Joint Conference : African Light Source, Pan African Conference on Crystallography, and African Physical Society

Africa/Johannesburg
Hosted by X-TechLab

Hosted by X-TechLab

by Zoom
, , ,
Description

The time zone is controlled by you as an Indico Setting (top right). The session times will therefore be shifted if you are not set to Central Africa Time (CAT) = GMT+2.

Welcome to the 2021 joint virtual meeting of the African Light Source (AfLS), the African Physical Society (AfPS), and Pan African Conference on Crystallography (ePCCr), co-convened with several other Pan African professional science societies, all hosted by X-TechLab.  We hope that you will join us as we communicate and celebrate Big Science and Big Goals for Africa!

ePCCr prizes

The winners of poster and speaker prizes, selected from participants in the ePCCr conference by a panel of judges, were announced at the conference closing ceremony. The winners are listed below.

All prize winners will receive a certificate and a USD200 prize. Thank you to all our generous sponsors.

Poster prizes

Crystal Growth & Design poster prizes

Akin Olaleru from Yaba college of Technology, Nigeria, Optimal conditions for preparation of perovskite crystals and thin film

Eddy F. Yusslee from the University Malyasia Sabah, Malaysia, Transformation of kalsilite from kaolinite via hydrothermal method

CCDC poster prizes

Tristan Theunissen from the University of Cape Town, South Africa, Silver(I) complexes with picoline derivative ligands: Synthesis, characterization, DFT and QTAIM calculation study

Hannah van Dyk from the University of the Free State, South Africa, The application of functionalized salicylidene Schiff base ligands in catalysis, luminescence, and radiopharmacy.

CrystEngComm poster prizes

Samantha Le Roux from Stellenbosch University, South Africa, Dithiadiazolyl radical co-crystal formation

Abraham Zigla Atour from theUniversity of Maroua, Cameroon,  Design, characterization and investigation of CO catalytic oxidation over Mg-modified Co3O4 catalyst

Speaker prizes

CrystEngComm speaker prizes

Cyrielle Dazem Fogou from the University of Yaounde 1, Cameroon, Topological diversity in Metal Oxalates and Structural Variability of Copper(II) oxalate anion associated with Pyridinium Derivatives Cations

Alan Eaby from Stellenbosch University, South Africa, Solvent-Mediated Elasticity in Flexible Single Crystals

ICDD speaker prize

Najlaa Hamdi from University Sidi Mohamed Ben Abdellah, Morocco, Crystal characterization and application of a new vanado-phosphate material

Participating Organisations

As advanced light sources support multiple disciplines, the AfLS conference formally includes participation by the following Pan African scientific societies, which we are proud to count as supporters and partners in our vision to establish an advanced light source on the African continent.

Programme Outline

The meeting program will cover a broad range of topics in four different tracks.

 Track 1 : AfLS : 14h00 - 19:00 CAT/GMT+2 Track 2 : ePCCr/AfCA : 09h00 - 17:00 CAT/GMT+2 Track 3 : AfPS : 09h00 - 19:00 CAT/GMT+2 Track 4 : Co-Convenors : 09h00 - 19:00 CAT/GMT+2

The format of this exciting virtual meeting will allow attendees to take full advantage of the overlap between the different participating organizations. All registrants will be able to attend sessions in any track with a single registration.

Contributed oral presentations and posters are welcome. Please identify the track of your participation at the registration and abstract submission phases.

Registrants will be sent the Zoom room links shortly before the conference. Each track will have its own Room within the same Zoom Session. All sessions will be lived streamed to YouTube.

The programme details, as they are updated, are available in the Timetable link on the left-hand menu.

Students and Early Career Scientists Welcome

There is a limited amount of financial support for students and early-career professionals for online data packages for the conference.  Applicants must first fully register and then apply using the link in the left panel.

Participation

The Joint Organizing Committee of this meeting observes the basic policy of non-discrimination and affirms the right and freedom of scientists to associate in international scientific activity without regard to factors such as ethnic origin, religion, citizenship, language, political stance, gender, sex or age, in accordance with the Statutes of the International Council for Science.

No barriers, which would prevent the participation of bona fide scientists, will exist at this meeting.

• Monday, 15 November
• 09:00 10:00
Gather.Town Meetings / Posters 1h
• 10:00 10:45
Opening Plenary: Address by Benin Minister (Prof. Eléonore Yayi Ladekan) / Session Chair: Marielle AGBAHOUNGBATA
1. AfLS Chair - 5 min
2. ePCCr Chair - 5 min
3. AfPS Chair - 5 min

Opening :
Ministry of Higher Education and Scientific Research

• 10:00
Welcome and Introduction 5m
Speaker: Marielle AGBAHOUNGBATA (Semi City)
• 10:05
Address by President of the AfLS 5m
Speaker: Simon Connell (University of Johannesburg)
• 10:10
Address by Chair of the ePCCr 4m
Speaker: Gift Mehlana (Zimbabwe Chemical Society)
• 10:15
Address by President of the AfPS 5m
Speaker: Ahmadou Wague (African Physical; Society)
• 10:20
Address - Ministry of Higher Education and Scientific Research (Prof. Eléonore Yayi Ladekan)) 25m
• 10:45 11:00
Gather Town

Meet informally in the Gather Town

• 11:00 12:00
Opening Plenary: (Scientific) by Dr. Thandeka Moyo-Gwete / Session Chair: Simon Connell
1. AfLS Chair - 5 min
2. ePCCr Chair - 5 min
3. AfPS Chair - 5 min

Opening :
Ministry of Higher Education and Scientific Research

• 11:00
Importance of structural biology in virology research: HIV, SARS-CoV-2 and beyond 1h

Understanding the structure-function relationship of viral proteins has aided in the discovery of vaccines and therapeutics for a range of infectious diseases. Although we still do not have an effective HIV vaccine, understanding the structure of rare broadly neutralizing antibodies (bNAbs) made in some individuals who are HIV-infected and how these antibodies interact with the HIV Envelope (Env) protein has shed light on how better to trigger these responses through immunization. The HIV Env protein is the sole target of bNAbs and the whole Env and subunits have been designed as immunogens. Structural biology has allowed for the understanding of which parts of the Env to focus on and how best to stabilize its structure. With the emergence of the COVID-19 global pandemic, there was an accelerated need for effective vaccines to prevent SARS-CoV-2 infection. Early in the pandemic, researchers solved the structure of the SARS-CoV-2 spike protein; the protein that is targeted by neutralizing antibodies. Within months, vaccines based on these spikes were being tested for safety and efficacy and then rolled out to the public. This could not have been possible without understanding the structure and function of the SARS-CoV-2 spike protein. Today, we still use this protein to understand the immune response that develops after SARS-CoV-2 infection and vaccination. Structural biology still plays an important role in the fight against various pathogens and will continue to be a powerful tool for future pandemics.

Speaker: Dr Thandeka Moyo-Gwete (National Institute for Communicable Diseases)
• 12:00 13:00
AfLS: None

Ceremonial African Speaking and Calling Sticks
Opening Plenary

• 12:00
Break / Gather.Town Meetings / Posters 1h
• 13:00 14:00
Gather Town: Break / Gather.Town Meetings / Posters

Meet informally in the Gather Town

• 14:00 15:00
Plenary: S. Reutzel-Edens
Convener: Gift Mehlana (Zimbabwe Chemical Society)
• 14:00
Inspiring Medicines Design through Solid-State Chemistry 1h

See attachment

Speaker: Susan Reutzel-Edens (Cambridge Crystallographic Data Centre)
• 15:00 16:00
AfLS Track: / Session Chair: Simon Connell
• 15:00
Transfer of the AfLS Calling Stick and Speaking Stick 10m
Speaker: Prof. Tabbetha Dobbins
• 15:10
Developing a Business Case for an International Research Infrastructure 25m

see attached file

Speaker: John Womersley (University of Oxford)
• 15:35
Mid-scale Instrumentation and Facilities for Materials Research 25m

[1] P. Lama, L. J. Barbour, J. Am. Chem. Soc. 2018, 140, 2145-2150.

Speaker: Shane de Beer (Stellenbosch University)
• 11:15
Synthesis and characterizationof Rhenium (I) tricarbonyl complexes with N,O-donor bidentate ligands on Re (I) metal center 15m

Over the years, the anticancer activity of inorganic compounds like metal complexes has been considered as one of their most important probable applications. The coordination complexes of platinum are the most widely used classes of drugs in cancer therapy and continue being the backbone of systematic cancer therapies since 1980. Although platinum-based drugs in cancer treatment routines are universal, several disadvantages exist which contribute to the need to explore and develop the potential of other organometallic complexes as chemotherapeutic agents. Tricarbonyl complexes with Rhenium (Re) as the central metal ion are of great interest to researchers and scientists due to their properties which are advantageous for the development of new anticancer drugs. The octahedral configurations of these Re (I) complexes are known to form high in vitro and in vivo stability and favorable pharmacokinetic properties. In this study, a range of Re(I) tricarbonyl complexes were synthesized using the '2+1' mixed ligand approach, and four crystal structures were obtained.

Speaker: Mabu Matlou (PCCr)
• 10:45 11:30
AfLS: None

Ceremonial African Speaking and Calling Sticks
Opening Plenary

• 11:00 11:45
ePCCr Track: Structural Chemistry & Crystal Engineering

Poster session will take place in GatherTown. You can access it by copying the link:
https://gather.town/app/txiF4xMdbAgSCtxJ/IndabaSpace

Convener: Dickson Andala (Multimedia University of Kenya)
• 11:00
The role of electrostatic interactions in maintaining three-dimensional networks in hybrid compounds based on nitrogen bases 15m
1. Introduction

Nucleobases are key structure directing agents due to their rich and diverse combination of hydrogen bond donor and acceptor positions. Their propensity to self-assemble through hydrogen-bonding interactions has led to a plethora of supramolecular structures. As a significant nucleobase of DNA, adenine is an important naturally occurring nitrogen heterocycle present in nucleic acids. Owing to its unique biological activity and multiple supramolecular interaction, adenine has been extensively studied in varieties of fields such as pharmacology [1] optoelectronics [2] and photovoltaic [3]. The different properties mentioned above are fundamentally correlated to the structural organizations and to the various intermolecular interactions that govern them

1. Results

The two adeninium based organic-inorganic hybrid compounds: adeninium hydrogen diselenite (I) and adeninium hydrogen selenite (II): were characterized by single- crystal XRD studies, and a well detailed structural study was illustrated.

The inspection of hydrogen bonding network in both compounds shows a direct hydrogen-bond interactions between the adeninium cations and the hydrogen (diselenite/selenite) anions. Furthermore, supramolecular homo and hetero-synthons found in (I) and (II) play an important role in shaping these supramolecular compounds. Moreover, the structural investigation shows that the 1H,9H-adeninium in both crystal structures generate cationic ribbons. In addition to the N—H •••N and C—H •••N hydrogen bonds connecting the purine bases in (I) and (II), weak stacking interactions are observed between the aromatic rings of the adeninium base in both compounds. The stacking of organic cations is stabilized in the crystal packing of (I) and (II) by the ionic bridges with the surrounding anions; indeed, anions play an important role in maintaining the three-dimensional network through hydrogen bonds and electrostatic charge-charge interactions. In (I) the anions exercise their role in solo while in (II) they do it as hexamers. Further, the connectivity between these hexamers in (II) generates a three-dimensional honeycomb-like inorganic framework. This effect should be considered as important in crystal engineering. There is an interesting electrostatic association, seen only in compound (I), between the SeOH oxygen electron lone pairs and the aromatic cation.

1. References

[1] H. Cai, S. Su, Y. Li, H. Zeng, Z. Zhu, J. Guo, et al. , J. Ethnopharmacol. 212 (2018) 153–165.
[2] I. Burneo, K.C. Stylianou, S. Rodríguez-Hermida, J. Juanhuix, X. Fontrodona, I. Imaz, D. Maspoch, Cryst. Growth. Des. 15 (2015) 3182–3189.
[3] H. Athmani, C. Kijatkin, R. Benali-Cherif, S. Pillet, D. Schaniel, M. Imlau, N. Benali-Cherif, E.-.E. Bendeif, Acta Cryst. A75 (2019) 107–114.

Speaker: Dr Rim Benali-Cherif (Abbes Laghrour Khenchela University)
• 11:15
Crystal Engineering of Co-crystal of Nicotinic acid and Pyrogallol: An Experimental and theoretical Electron density Analysis Alia Iqbala, Arshad Mehmoodb, Sajida Noureena, , Claude Lecomte,d, Maqsood Ahmeda 15m

Experimental electron density analysis by means of high resolution X-ray diffraction data up to sinθ/λmax=1.11Å-1 at 100(1) K has been performed to analyze the detailed structure and the strength of intermolecular interactions responsible for the formation of a new solid form of Nicotinic acid (NA), cocrystallized with Pyrogallol (PY) with two NA-PY units in the asymetyric unit. The refinement were carried out using the Hansen and Coppens multipolar formalism (program Mopro). The 2:2 cocrystal of NAPY exhibits a zig-zag, brick stone and sheet like layered structure along 3D and is stabilized by strong intra and inter-molecular hydrogen bonding through N¬-H‧‧‧O and O-H‧‧‧O bonds, some of them due to the zwitterion nature of NA as well as weak interactions between the PY molecules. Ranking these interactions via topological analysis of the electron density shows the leading role of the NA···NA sublattice which drives the cocrystals organization. These strong interactions between the NA zwitterions may explain why Z’=2 and why the NA substructure has a larger symmetry than that of the cocrystals .

Speaker: Claude Lecomte (CRM2 University of Lorraine)
• 11:30
Invited Lecture: Design, Describe, Disseminate: The use of Network Topology in MOFs & Related Materials and the role of IUPAC 15m
1. Why Metal-Organic Frameworks?
Water harvesting from desert air, biogas storage, drug delivery, catalysis, carbon capture, destruction of chemical
weapons, and more energy efficient air conditioners are but some potential applications of Metal-Organic
Frameworks, MOFs. The wide-ranging capabilities of these new materials are due to the tunability, high surface
area, porosity and large internal void spaces made possible by networks of single- or multi-metallic nodes

2. Why Topology?
The empty space inside the MOFs is controlled by the framework topology and the linker size, but network
topology is a much broader concept in solid state chemistry. I will describe how network topology analysis can
applied to different fields of solid-state chemistry. Its usefulness is demonstrated by examples from metal–organic
frameworks, group 14 allotropes and related compounds, ice polymorphs, zeolites, supramolecular (organic) solidstate
chemistry, Zintl phases, and cathode materials for Li-ion batteries.[2]

3. Why IUPAC and how do we collaborate in an equal and inclusive way?
I will also highlight how IUPAC has worked with topics related to MOFs,[3] and give some reflections on
international cooperation based on my experience from the Berkeley Global Science Institute and numerous
projects financed by the Swedish International Development Agency[4].

4. References
[1] L. Öhrström, F. M. Amombo Noa, Metal–Organic Frameworks DOI: 10.1021/acs.infocus.7e4004, American Chemical Society (2021)
[2] L. Öhrström, Chem. Eur. J., 22 (2016) 13758-13763
[3] (a) S. R. Batten, N. R. Champness, X. M. Chen, J. Garcia-Martinez, S. Kitagawa, L. Öhrström, M. O'Keeffe, M. P. Suh and J. Reedijk,
Pure and Appl. Chem., 85 (2013) 1715–1724, (b) C. Bonneau, M. O’Keeffe, D. M. Proserpio, V. A. Blatov, S. R. Batten, S. A. Bourne, M. S.
Lah, J.-G. Eon, S. T. Hyde, S. B. Wiggin and L. Öhrström, Cryst. Growth Des., 18 (2018) 3411-3418
[4] L. Öhrström, P. Weiderud, M. A. Youssef and O.M. Yaghi, Science & Diplomacy, 7 (2018)
https://www.sciencediplomacy.org/perspective/2018/global-engagement-in-science-universitys-fourth-mission

Speaker: Prof. Lars Öhrström (Chalmers University of Technology)
• 11:30 11:45
Gather Town

Meet informally in the Gather Town

• 11:45 13:00
AfLS: None

Ceremonial African Speaking and Calling Sticks
Opening Plenary

• 11:45 13:00
AfPS - Optics/Photonics
• 11:45
Dielectric Property Estimation of Paraffin Wax Solid from Signal Measurement of an Optical Fourier Domain Imaging System. 15m

Estimating the dielectric properties of materials help obtain useful information for characterization of materials. In this research, Kramers-Krogin relation and the Debye model is applied to an interferogram of paraffin wax solid as sample in an implemented Optical Fourier Domain Imaging (OFDI) System using microwave signals as source. The real (ϵ_1 ) and imaginary (ϵ_2 ) components of the dielectric constant is extrapolated as the frequency approaches zero (ω→0). A simple microwave experiment using Snell’s Law is performed and results obtained is compared to that from application of Kramers-Krogin relation and Debye Model to the signal measurement from the OFDI system with paraffin wax solid as sample.
Keywords: Optical Fourier Domain Imaging (OFDI), Kramers-Krogin relation (K-K relation)

Speaker: Rodney Abugre (University of Ghana)
• 12:00
Elastic and Magnetic Properties of Tb-MnO Based Thin Films 15m

Multiferroic materials are a class of materials exhibiting correlations in their ferroic orders. Light interaction with lattice vibrations is a powerful method to study the elastic properties of solids using surface Brillouin scattering (SBS). SBS is based on the inelastic scattering of photons by acoustic modes (phonons) to determine the elasticity of materials. In this work, ferroelastic and magnetic properties of rare-earth complex oxides thin films are investigated. The phonon velocities were measured at room temperature using a solid-state laser (λ=532 nm) at an incidence angle of 60o. The measured data was optimized and fitted with data simulated using surface elastodynamic Green’s function for discrete phonon dispersion in the k||d range of 0–5. By the least-squares fitting approach, we obtain the uncertainties of measurement from Taylor series expansion of the phonon phase velocity dependence on the primary elastic constants (C11 and C44), yielding the optimum values as C11 = 180±4.90 GPa, and C44 = 43±0.89 GPa. The films were isotropic and so using Cauchy’s relation (C12 = C11-2C44), C12 was obtained as 94 GPa. From this set of elastic constants, the derived moduli were obtained as follows: Young’s modulus (E) = 116 GPa, Shear modulus (G) = 43 GPa, Bulk modulus (B) = 123 GPa, Cauchy pressure (C12-C44) = 51 GPa Poisson’s ratio (v) = 0.34, and Pugh’s ratio (B/G) = 2.85. On the other hand, the magnetic properties of the films have been studied by vibrating sample magnetometry (VSM). The films have exhibited ferromagnetic ordering at T<150 K. A spin-glass-like behaviour associated with competing ferromagnetic and antiferromagnetic magnetic ordering has also been observed at T~50 K from isofield measurements.

Keywords: Multiferroics, phonon dispersion, ferromagnetism, spin-glass.

Speaker: Mr Geoffrey Mwendwa (School of Physics, Material Physics Research Institute, University of the Witwatersrand, Private Bag 3, 2050, South Africa)
• 12:15
Photonic Cooperativity & Coherence in Microtubule Architectures 15m

We investigate the photonic inner workings of the living cell by studying interactions of short-wavelength ultraviolet photons with extremely large networks of UV-absorbing chromophores acting as an open quantum system. The cytoskeleton provides the structural organization of the cell, as the supporting architecture for all eukaryotic forms of life. A major structural unit of this architecture is the cellular “microtubule,” a cylindrical body composed of individual units of the protein “tubulin” organized in an array of morphologically dynamic spirals. Recently, our group (www.quantumbiolab.com) has predicted that microtubules exhibit very useful quantum optical properties, supporting the myriad of already well-known structural features. In this work, we explore the role that electronic superradiance may play in facilitating coherent excitonic transport and signaling within the cellular architecture, from the cytoskeleton to the eukaryotic centriole—and beyond.

Speaker: Nathan Babcock (Quantum Biology Laboratory, Howard University)
• 12:30
The LAM Network an instrument for panafricain cooperation in optical sciences 30m

The LAM network an instrument for pan African cooperation in optical Sciences
A. Wague
African Physical Society

Since its creation on May 1992 in Dakar the African laser Atomic molecular and optical science network(LAM network), the LAM network immediately oriented his activities for scientific cooperation between African scientists in the field of laser sciences and applications. The first instrument in establishing the links between scientists from different countries was the immediate collaborative actions between Senegal Ghana Zimbabwe Cote d'Ivoire and Sudan in strong cooperation with ICTP in the field of laser spectroscopy with applications in Agriculture and environment. Other activities was oriented since 1993 in organization of international workshops in laser and
applications and also in organization of school in optics with handsome experiments in all the 5 region in Africa together with the establishment of exchange of student and staff for training programs..
In IUPAP Congress in Berlin in 2002 the activities of the LAM constituted the main presentation of C13 commission on physics for development . The LAM contributed strongly in development of laser sciences in many places in West Africa Central Africa East North and South Africa by organizing schools and workshops. The LAM network was among the founding member of African laser Centre based in Pretoria. In the launching speech of African Laser Centre in 2003 in Pretoria the president of LAM strongly underlined the necessity for Africa to have heavy laser infrastructures in many nodal points in the Continent. The LAM have also established strong collaborative actions with ICTP and international societies in optics a and with university of Lund and university of Uppsala in the framework of SIDA and ISP programs in Africa. Today the lam is an international society Member of ICO and through the activities of the LAM the African physical society was lunched in Senegal in 2010 and the African Optics and Photonics Society was also launched in Dakar in 2014. The LAM was also in other different activities like celebration of international year of light in 2015 in Paris, Ghana, in Senegal. the LAM is continuing his road with outreach programs with student’s science clubs at National Academy of Science and Techniques in Senegal . With ICTP and ICO the LAM is participating to TSOSA program for the organization of ICTP winter college in optics .
The LAM is also working with African Physical Society and other international optical societies for the development of optical sciences in Africa.

Speaker: Ahmadou Wague (African Physical; Society)
• 11:45 12:30
ePCCr Track: No Talks Scheduled

Poster session will take place in GatherTown. You can access it by copying the link:
https://gather.town/app/txiF4xMdbAgSCtxJ/IndabaSpace

• 12:30 13:00
ePCCr Track: ePCCr Poster Session on GatherTown

Poster session will take place in GatherTown. You can access it by copying the link:
https://gather.town/app/txiF4xMdbAgSCtxJ/IndabaSpace

• 13:00 14:00
Gather Town: Break / Gather.Town Meetings / Posters

Meet informally in the Gather Town

• 13:00 14:00
Plenary: Plenary: S. Abdel-Aal
Convener: Prof. Andreas Roodt (University of the Free State)
• 14:00 15:00
Plenary: by Prof Francesco Petruccione / Session chair : Onime Clement
• 14:00
Recent developments in the African Theoretical, Computational and Quantum Sciences Research space 1h

During the Covid-19 pandemic, two exciting developments in the South African research space occurred: The South African Quantum Technology Initiative (SA QuTI) and the new National Institute for Theoretical and Computational Sciences (NITheCS) started their activities.

I will present the two initiatives and stress their relevance and opportunities for the African scientific community in the talk.

Speaker: Francesco Petruccione (UKZN)
• 15:00 16:00
AfLS Track: Universities and Light Sources / Session chair : Tabbetha Dobbins
• 15:00 16:00
AfPS-AMRS-ANNS
• 15:00
Overview PETRA III and outlook to PETRA IV 15m

In the presentation a brief overview about the beamline portfolio and research infrastructure at the Synchrotron Radiation Source PETRA III including selected scientific highlights and details about the user operation during the Corona pandemic will be given. This will be followed by a brief outlook to the envisaged upgrade of the machine to the 4th generation source PETRA IV.

Speaker: Dr Hans-Christian Wille (Deutsches Elektronen-Synchrotron)
• 15:15
Short Antimicrobial peptides: Small-angle X-ray Scattering as a tool to study membrane interactions on bacterial membrane models 15m

The increased prevalence of multi antibiotic-resistant pathogens has been listed by the World Health Organisation (WHO) as one of the biggest threats to modern day healthcare, food security and development.1 It is essential to drive the discovery of new alternate antimicrobials now, due to the time taken to for molecules to undergo clinical trials, and the rate in which multiple drug resistant strains are arising.

Here I will discuss small angle x-ray scattering to study membrane interactions of different antimicrobial peptides with membrane models based on different bacterial species and how this information can be used to increase design tunability when designing membrane disrupting AMPs.

Speaker: Charlotte Edwards-Gayle (Diamond Light Source)
• 15:30
The structures of the C146A variant of the amidase from Pyrococcus horikoshii bound to glutaramide and acetamide suggest the basis of amide recognition 15m

S. Makumire, S. Su, B.W. Weber, J.D. Woodward, S.W. Kimani, R. Hunter and B.T. Sewell
DEPARTMENT OF INTEGRATIVE BIOMEDICAL SCIENCES, AARON KLUG CENTRE FOR IMAGING AND ANALYSIS, UNIVERSITY OF CAPE TOWN

The nitrilase superfamily enzyme from Pyrococcus horikoshii is an amidase that binds to and hydrolyzes several different amides. Amide substrate docking studies on the wild type and C146A variant P. horikoshii amidase suggest a sequence in which the incoming amide substrate initially hydrogen bonds to the amino group of Lys-113 and the backbone carbonyl of Asn-171. When steric hindrance is relieved by replacing the cysteine with alanine, the amide then docks such that the amino group of Lys-113 and the backbone amide of Phe-147 are hydrogen-bonded to the substrate carbonyl oxygen, while the backbone carbonyl oxygen of Asn-171 and the carboxyl oxygen of Glu-42 are hydrogen-bonded to the amino group of the substrate. We confirmed the location of the acetamide and glutaramide ligands experimentally in well-resolved crystal structures of the C146A mutant of the enzyme from P. horikoshii. This ligand location suggests that there is no direct interaction between the substrate amide and the other active site glutamate, Glu-120, and supports an active-site geometry leading to the formation of the thioester intermediate via an attack on the si-face of the amide by the sulfhydryl of the active site cysteine.

Speaker: Stanley Makumire
• 15:45
ForMAX – a new beamline for multi-scale structural characterization of hierarchical materials 15m

Joaquín González, Vahid Haghighat, Samuel A. McDonald, Kim Nygård

MAX IV Laboratory, Lund University, Sweden

ForMAX is a new beamline initiative at the MAX IV Laboratory, combining small- and wide-angle x-ray scattering (SWAXS), scanning SWAXS imaging, and full-field microtomography for multi-scale structural characterization of hierarchical materials from nm to mm length scales, with temporal resolution to study materials processes in situ under specific environments. ForMAX is funded by industrial partners and private foundations to advance research and development of novel materials and specialty chemicals from renewable forest raw materials, but the beamline will also be open for general users. Here we will describe the beamline concept, focusing on the novel combination of SWAXS and full-field tomography. ForMAX is presently in construction phase, with commissioning expected to commence in early 2022.

Speaker: Dr Kim Nygård (MAX IV Laboratory)
• 15:00 15:45
ePCCr Track: Large Facilities and Equipment

Poster session will take place in GatherTown. You can access it by copying the link:
https://gather.town/app/txiF4xMdbAgSCtxJ/IndabaSpace

Convener: Dickson Andala (Multimedia University of Kenya)
• 15:00
How to manage a modern X-ray scattering lab – a modest example 15m
1. Introduction

A good laboratory organization can help address the reproducibility crisis in science, and easily multiply the scientific output of a laboratory, while greatly elevating the quality of the measurements. We have demonstrated this for small- and wide-angle X-ray scattering in the MOUSE project (Methodology Optimization for Ultrafine Structure Exploration) [1]. In the MOUSE, we have combined: a) a comprehensive laboratory workflow with b) a heavily modified, highly automated X-ray scattering instrument. This combination allows us to collect fully traceable scattering data, with a well-documented data flow (akin to what is found at the more automated beamlines). With two full-time researchers, the lab collects and interprets thousands of datasets, on hundreds of samples for dozens of projects per year, supporting many users along the entire process from sample selection and preparation, to the analysis of the resulting data.

While these numbers do not light a candle to those achieved by our hardworking compatriots at the synchrotron beamlines, the laboratory approach does allow us to continually modify and fine-tune the integral methodology. So for the last three years, we have incorporated e.g. FAIR principles, traceability, automated processing, data curation strategies, as well as a host of good scattering practices into the MOUSE system. We have concomitantly expanded our purview as specialists to include an increased responsibility for the entire scattering aspect of the resultant publications. This ensures full exploitation of the data quality, whilst avoiding common pitfalls.

1. Talk scope

This talk will present the MOUSE project as implemented to date, and will introduce foreseeable upgrades and changes. These upgrades include better pre-experiment sample scattering predictions to filter projects on the basis of their suitability, exploitation of the measurement database for detecting long-term changes and automated flagging of datasets, extending the measurement range through an Ultra-SAXS module [2], and enhancing MC fitting [3] with sample scattering simulations for better matching of odd-shaped scatterers.

1. References

[1] Smales, G. J., and Pauw, B. R. The MOUSE project: a meticulous approach for obtaining traceable, wide-range X-ray scattering information. Journal of Instrumentation. 16, P06034 (2021). DOI: 10.1088/1748-0221/16/06/P06034
[2] B. R. Pauw, A. J. Smith, T. Snow, O. Shebanova, J. P. Sutter, J. Ilavsky, D. Hermida-Merino, G. J. Smales, N. J. Terrill, A. F. Thünemann and W. Bras: Extending synchrotron SAXS instrument ranges through addition of a portable, inexpensive USAXS module with vertical rotation axes. Journal of Synchrotron Radiation 28 (3). DOI: 10.1107/S1600577521003313
[3] I. Breßler, B. R. Pauw, A. F. Thünemann, McSAS: A package for extracting quantitative form-free distributions, Journal of Applied Crystallography 48: 962-969, DOI: 10.1107/S1600576715007347

Speaker: Brian Richard Pauw (German Federal Institute for Materials Research and Testing (BAM))
• 15:15
COMSTECH-IUCr Collaboration to Enhance Capacity Building in Emerging Sciences Related to X-ray Crystallography 15m

OIC, The Organization of the Islamic Conference is comprised of 57 Muslim nations and representing the second largest international organization after the United Nations. Including several oil- and gas-producing nations of Middle East, the OIC nations also include some of the world’s poorest countries as well as large middle-income countries with regions of great poverty along with highest infection rates and endemicity of the neglected tropical diseases (NTDs) including leishmaniasis, schistosomiasis, ascariasis, trichuriasis, hookworm, trachoma, chagas, malaria, HIV, etc.
COMSTECH (http://www.comstech.org/) is a Ministerial Standing Committee on Scientific and Technological Cooperation of the Organization of Islamic Cooperation (OIC) that was brought into existence by the Third Islamic Summit Conference held in Makkah al Mukarramah/Taif in January 1981. The President of the Islamic Republic of Pakistan is its Chairman. The Committee is entrusted with the follow up of the implementation of resolutions adopted by the Islamic Summit in the fields of science and technology, examining all possible means of strengthening cooperation among the OIC member states in those areas of science and technology that are crucial for the scientific development of the OIC region, and putting forward programs and proposals likely to improve the scientific and technological capabilities of the OIC member states.
Given that the charter of the both COMSTECH and IUCr includes scientific cooperation, and capacity building, the cooperation of both networks to build capacity of Developing world in the emerging areas of science.

Following COMSTECH- NTD network joint activities will be conducted for capacity building of researchers / scientists of Muslim world to address the growing issue of leishmaniasis from the plate form of COMSTECH.

1. Workshops for Capacity Building
2. Virtual lecture series on basic and advanced techniques to use for research related to X-ray crystallography
Speaker: Prof. M. Iqbal Choudhary (COMSTECH)
• 15:30
The new D8 QUEST ECO – chemical crystallography for all 15m

The D8 QUEST ECO is an affordable and robust instrument for chemical crystallography in research and teaching. The bright, long-life molybdenum X-ray source is ideal for a wide range of crystal types analysed in chemistry, geosciences and materials research laboratories. The new D8 QUEST ECO is now equipped with the PHOTON III 7 photon-counting detector that combines the key features of a large active area, photon-counting and zero readout deadtime. The new D8 QUEST ECO is run by the new software suite, APEX4. APEX4 features the most advanced automation utilised A.I. and machine learning to ensure that even occasional users can be confident of collecting the right data to correctly solve molecular structures.
The D8 QUEST ECO is an investment that can grow with your research. Based on the same platform as the D8 QUEST, the ECO can be upgraded to increase research output or access a wide variety of specialised or challenging measurements.

Speaker: Dr Vernon Smith (Bruker AXS)
• 15:45 16:00
Break 15m
• 16:00 17:00
Plenary: R. Garrett
Convener: Prof. Catharine Esterhuysen (Stellenbosch University)
• 16:00
Protein crystallography off the beaten track: Septin filaments, their role in disease and the importance of access to large facilities 1h
1. Introduction

Septins are GTP-binding proteins which are taken to be the fourth filamentous component of the cytoskeleton and play a fundamental role in cell division. In humans there are 13 different septins, one of which has been recently described to be an off-target substrate for the Zika virus protease. The C-terminal cleavage of septin 2 leads to deficient cell division in neuroprogenitor cells which is believed to be at least partly responsible for microcephaly in new-born infants.

1. Results

For the last 15 years we have been attempting to dissect the structure of septins and thereby shed light on their roles in both physiological and pathological processes. Our crystallographic studies have been supported by a plethora of biophysical techniques using research infrastructure from around the world and culminating in the determination of the first 3D structure of a hexameric septin complex solved by cryo-electron microscopy.

The hexamer is one of the basic building blocks of the mature filaments and its structure, together with the isolated C-terminal fragment, has allowed us to rationalize how cleavage by the viral protease affects filament assembly. Our studies have also provided insight into how nucleotide binding and hydrolysis affect filament shrinkage and expansion, how filaments bend and recognize membrane curvature and how cross-bridges are formed during filament bundling. All of the events are important for septin function and will be described in detail during the talk.

Speaker: RIchard Garratt (University of São Paulo)
• 17:00 17:15
Gather Town

Meet informally in the Gather Town

• 17:15 19:00
AfLS Track: Academies, Partners and Stakeholders / Session chair : Igle Gledhill
• 17:15 19:00
AfPS-AMRS-ANNS
• 17:15
Simulating X-ray Spectroscopy using a Many-Body Representation based on Kohn-Sham Density Functional Theory 15m

There is an increase in the use and study of X-ray spectroscopy of materials in order to understand their electronic structure. Computational studies can aid in these investigations. Starting from electronic structure obtained using DFT, our work simulates the spectrum of benzene molecules and that of solid graphene by incorporating the core-hole effects with the single-particle full core-hole (FCH)approach and Many-Body X-Ray Absorption Spectroscopy (MBXAS) [1,2]. MBXAS uses the determinant approach to calculate the core-hole spectra of systems, taking eigenvalues and eigenstates from DFT calculations. MBXAS computes the transition dipole-moment corresponding to X-ray absorption by approximating the final (initial) state as a Slater determinant constructed using Kohn-Sham orbitals obtained in the presence (absence) of the core electron. A comparison of the electronic band structure calculated with and without the core-hole, respectively, reveals a significant core-hole binding effect, i.e., excitons, for both the molecular benzene and the extended two-dimensional system, graphene. Furthermore, this approach provides direct access to the spatial distribution of the excited state orbitals for the purpose of analysis of XAS spectral peaks. This permitted us to draw parallels between the X-ray excited states of benzene and graphene which share certain local symmetries in atomic arrangement and corresponding electronic structure. Density of states analysis reveals the energies of excitonic peaks and their relationship with the initial-state band structure.

[1] Yufeng Liang, John Vinson, Sri Pemmaraju, Walter Drisdell, Eric L. Shirley, and David Prendergast. Accurate X-ray Absorption Predictions for Transition Metal Oxides: An Advanced Self-Consistent-Field Approach Inspired by Many-Body Perturbation Theory. Phys. Rev. Lett. 118, 096402 (2017).
[2] Yufeng Liang, David Prendergast. Quantum Many-Body Effects in X-Ray Spectra Efficiently Computed using a Basic Graph Algorithm, Physical Review B 97, 205127 (2018).

Speaker: Olaiya OLOKUNBOYO (ICTP-EAIFR, University of Rwanda)
• 17:30
INFUENCE DE LA TEMPERATURE SUR LA VISCOSITE DES SOLS ARGILEUX DE LA COMMUNE DE HOUEYOGBE 15m

De nombreuses catastrophes naturelles dont nous pouvons citer entre autres le glissement de terrain, les coulées de boue ainsi que les phénomènes de retrait-gonflement des sols argileux ont pour conséquence l’état délabré des différentes infrastructures ; ce qui handicape leur pérennité de même que la sécurité de leurs usagés. Ces phénomènes s’exhibent plus dans la dépression de la Lama au Bénin en occurrence dans la commune de HOUEYOGBE. Il requiert donc de chercher comment les températures saisonnières influent sur la viscosité de ces sols argileux. Cette étude a été menée sur des boues de sols argileux de concentration volumiques 30%. D’après les résultats, la viscosité dynamique de la boue argileuse diminue avec l’augmentation de la température.

Speaker: Mr Zodier Virtus TOHOUNGBA (Ecole Doctorale des Sciences de l'Ingénieur (ED-SDI))
• 17:45
Radiations hardness of nanocrystalline nickel under 450 keV protons 15m

This contribution reports on the effects of 450 keV proton irradiation within the 1015–
1017H+/cm2 fluence range on nano-crystalline Ni thin films. The surface and in-volume
induced damages were investigated by grazing incidence X-rays diffraction, atomic force
microscopy, Rutherford backscattering as well as four-point probe resistivity measurements.
Within such a type of H+ irradiation, a significant surface roughening and amorphization of
the external parts of the Ni crystallites for the lowest fluence (1015 H+/cm2 and a recrystallization for higher fluences (1016–1017 H+/cm2) was observed.

Speaker: Prof. Malik Maaza (Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation)
• 18:00
Zinc zirconate (ZnZrO3) nanocomposites bimetallic designed by green synthesis via Moringa Olefeira extract for high-performance electrochemical applications 15m

In this work, we report a simple and eco-friendly method of synthesizing ZnZrO3 nanocomposites by green approach method using Moringa Oleifera natural plant extract that acted as both capping and reducing agent via their photochemical. The proposed mechanism towards the formation of ZnZrO3 nanocomposites in view of understanding the interaction of Zn (II) and Zr (IV) ions through biological compounds of Moringa Oleifera extract was designed from FTIR analysis. The physical and electrochemical properties were characterized using different techniques such as High Resolve Transmission Electron Microscope (HRTEM) Energy Dispersive X-ray Spectroscopy (EDS) X-ray diffraction (XRD) Fourier transform infrared (FT-IR) Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrochemical analysis clearly revealed redox peaks at around peak potentials of 0.075 (peak III) and - 0.563 V (peak IV) during the cathodic cycle, due to the reduction and around - 0.252 (peak I) and 0.207 (Peak II), corresponding to the oxidation of ZnZrO3 nanocomposites. The excellent electrochemical performances suggest that ZnZrO3 nanocomposites are highly suitable for electrochemical applications due to their good voltammetric response, high electro-activity, and good electrochemical kinetics.

Speaker: Dr Nolubabalo Matinise (University of South Africa)
• 18:15
Ternary MnxNi1-xCo2O4 spinel oxides for oxygen reduction and supercapacitor applications; the role of carbon support and tunning metal compositions 15m

In this study, a systematic investigation of ternary spinel oxides MnxNi1-xCo2O4 (x = 0, 0.3, 0.5, 0.7, and 1) was carried out to understand the effect of metal compositions and the role of carbon support on the structural and electrocatalytic properties. Characterizations using XRD, Raman, N2 adsorption/desorption, XPS, TEM, and SEM were done to get an insight into the structural, morphological, and surface properties of the materials. The electrocatalytic and supercapactive properties were performed using potentiostat/galvanostat and RDE techniques.

Speaker: Dr Tarekegn Heliso Dolla (Wollaita Sodo University)
• 18:30
Quantification of nano-dispersion in polymer nanocomposites: A thermodynamic analogy 15m

Nanoparticles in solution are characterized by colloidal thermodynamics such as the second virial coefficient and Debye charge screening. We have found that this approach can be adapted to kinetic mixing in Banbury mixers, twin screw and single screw extruders. An analogy is made between thermal dispersion and kinetic dispersion. This allows adaptation of the van der Waals model to describe nanoscale dispersion in terms of enthalpic interactions and excluded volume. Enthalpic interactions can be in the form of specific interactions that lead to correlated nanoparticles or mean field interactions that result in disordered particles. Specific Coulombic interactions display Debye screening that can result in a critical concentration where a transition between specific and mean field behavior is observed. In many situations, such as elastomer reinforcement, nano-scale dispersion is not optimal since agglomeration on the nano-scale can enable the formation of a network on macroscopic scales associated with properties such as tear resistance.

Speaker: Greg Beaucage (Department of Chemical and Materials Engineering, University of Cincinnati)
• 18:45
Biosynthesis of Adansonia Digitata Leaves' Mediated TiO2 Nanoparticles 15m

High purity Titanium dioxide TiO2 nanoparticles are bio-synthesized for the first time via a natural extract of the African indigenous Adansonia digitata leaves. The nanoparticles are thermally oxidized in air for 2 hours at annealing temperatures of 700, 800 and 900°C.
Subsequently, the nanoparticles are characterized for their functional groups identification, morphological and optical properties. The XRD patterns showed well-defined peaks of anatase and rutile phases, while the FTIR revealed peaks at 498 and 753 cm-1 assigned to vibrational modes of the Ti-O and the Ti-O-Ti groups respectively. TEM analysis revealed spherical shape nanoparticles with averaged grain size estimated as 3.94, 29.15, and 45.4 nm for TiO2 700, TiO2 _800 and TiO2 _900°C respectively. Furthermore, the Adansonia digitata leaves assisted TiO2 nanoparticles showed an excellent photodegradation ability of 92 % towards methylene blue dye within120 minute.
Keywords: Photocatalyse Activity; Biosynthesis; Titanium Dioxide Nanoparticles; Adansonia Digitata; Leaves Extract

Speaker: Mr Adama FALL (University of South Africa (UNISA))
• 19:00 19:30
Gather Town

Meet informally in the Gather Town

• Friday, 19 November
• 08:00 09:00
Gather Town

Meet informally in the Gather Town

• 09:00 11:00
AfLS: None

Ceremonial African Speaking and Calling Sticks
Opening Plenary

• 09:00 10:00
AfPS-FASBMB
• 09:00
Structural and functional characterization of the secreted adhesion EtpA of enterotoxigenic Escherichia coli 15m

Toxin delivery in enterotoxigenic Escherichia coli (ETEC) is preceded by bacterial adherence and colonization of the host small intestine. The secreted adhesin EtpA is thought to promote adherence by binding to the tips of ETEC flagellae. EtpA is part of a two-partner secretion system (TPS), used to secrete large virulence factors in Gram-negative bacteria. TPSs consist of a secretory passenger protein (TpsA) and a membrane-integral transporter (TpsB) that secretes TpsA across the outer bacterial membrane. TpsAs are high molecular weight proteins characterized by repeat sequences that share a conserved, N-terminal TPS domain of ~250 residues for secretion and folding.
EtpA is an example of a TpsA. Four consecutive 228 amino acid repeats of unknown function constitute the C-terminal region of EtpA, with additional repeats within each 228 residue repeat. We separated the N-terminal TPS domain (residues 68-447) and the C-terminal repeat domain (residues 448-1767) of EtpA, and simplified the latter by centrally removing three of the four repeats. We characterized both N- and C-terminal fragments by circular dichroism and solved the crystal structure of the N-terminal domain at 1.76 Å resolution. The structure reveals a right-handed parallel β-helix consisting of two hairpins, an extra-helical motif and an N-terminal region capped by β-strands (Fig 1). As with other TPS domains, the conserved β-helix is presumably critical for secretion and folding of EtpA. A structural model by AlphaFold of the C-terminal region indicates another β-helix with distinct continuity between the domains. Thermal unfolding assays by circular dichroism spectroscopy indicated that both N- and C-terminal domains have similar melting temperatures of between 55 and 60°C. Chemical unfolding with urea, by contrast, revealed N-terminal domain unfolding to be reversible. This was not observed for the C-terminal domain. This would imply that the EtpA N-terminal domain is able to autonomously fold during secretion, providing a template for the folding of the C-terminal domain by extending the common -helix. Attempts to purify full-length EtpA were discontinued due rapid degradation and low solubility of the protein. Unexpectedly, molecular pulldown assays with both N- and C-terminal domains of EtpA failed to show any interaction with flagellin implying that other factors may be involved.

Speaker: Clifford Manyo Ntui (University of Pretoria)
• 09:15
Broad-band luminescence involving fluconazole antifungal drug in a lead-free bismuth iodide perovskite: Combined experimental and computational insights 15m

The synthesis and characterization of a lead-free perovskite-type material, (C13H14N6F2O)2Bi2I10 is reported. It exhibits a zero-dimensional (0D) Bi2I104- octahedral unit, surrounded by a flexible tripodal antifungal ligand (H2Fluconazole)2+. The several intermolecular interactions of the independent cation and the bismuth iodide octahedra were tested via the Hirshfeld surface analysis. The detailed interpretation of the vibrational modes was
carried out. The band gap (Eg) of 2.10 eV agrees with the theoretical values. Upon photoexcitation, the crystals exhibit a broadband green emission peaked at 534 nm, which originates from electronic transitions within the inorganic cluster [Bi2I10]4-. The theoretical calculations were carried out using DFT and TD-DFT methods to appraise the molecular geometry, vibrational spectra, electronic absorption spectra, frontier molecular orbitals (FOMs) and global reactivity descriptors. Calculations reveal that the energy gap (Eg) and other chemical reactivity descriptors are primarily linked to the inorganic anion and the triazolium rings (A and B) of the organic cation reflecting their importance in the activity and the antioxidant ability of the molecule

Speaker: Dr Ferjani Hela (Imam Ibn Saud Islamic University)
• 09:30
Regulation of actin dynamics by phosphoinositides 15m

The actin cytoskeleton powers membrane deformation during many cellular processes. Here, we applied biochemical assays and atomistic molecular dynamics simulations to uncover the molecular principles by which ABPs interact with phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], one of the phosphoinositides. We reveal that these proteins demonstrate large differences in the affinities and dynamics of membrane interactions, and in the ranges of PI(4,5)P2 densities that they sense. Profilin and cofilin show transient, low-affinity interactions with PI(4,5)P2-containing membranes, whereas actin assembly factors Dia2 and N-WASP reside on PI(4,5)P2-containing membranes for longer periods to perform their functions. Ezrin and moesin, which link the actin cytoskeleton to the plasma membrane, bind membranes with high affinity and slow dissociation dynamics. Unlike profilin, cofilin, Dia2, and N-WASP, they do not require high ‘stimulus-responsive’ PI(4,5)P2 density for membrane binding. Together, these findings suggest that membrane-interaction mechanisms of ABPs evolved to precisely fulfill their specific functions in cytoskeletal dynamics.

Speaker: Dr Yosuke Senju
• 09:00 10:00
ePCCr Track: No Activities Scheduled

Poster session will take place in GatherTown. You can access it by copying the link:
https://gather.town/app/txiF4xMdbAgSCtxJ/IndabaSpace

• 10:00 11:00
AfPS-AMRS-ANNS
• 10:00
Chemical Bath (CBD) Synthesized Transition Metals/GO Composites Oxides Nanomaterials for Supercapacitive Electrodes 15m

CBD synthesized electrodes were produced for usages in supercapacitors. Graphene oxide (GO) was incorporated in the nanocomposites used for electrodes synthesis due to its great surface area and electrical conductivity. The synergistic alliance among these composites and GO enhance electrodes performance, life span and stability. The structural properties as obtained from the X-ray diffraction (XRD) results suggest that nanocomposites are crystalline in nature. The morphological studies indicated that the nanocomposites have platelet nanoparticles with some agglomerations. The energy bandgaps estimated for the Co3O4/GO, MnO2/GO, NiO/GO and Co3O4/MnO2/NiO/GO were 2.38eV, 2.05 eV, 2.50 eV and 2.33 eV respectively. The electrochemical studies provided highest specific capacitance from CV using 10 mV/s scan rates and GCD using 1.0 A/g current density were 765, 1215, 1518, 1674 and 975, 1358, 1432, 1718 F/g for Co3O4/GO, MnO2/GO, NiO/GO and Co3O4/MnO2/NiO/GO respectively. These results obviously indicate that composites perform better than single transition metal oxide and the addition of graphene oxide enhanced electrodes performance.

Speakers: Prof. M Maaza (University of South Africa) , Mrs Ebere Nsude (University of Nigeria, Nsukka) , Mr Edwin Onoh (University of Nigeria, Nsukka)
• 10:15
High light absorption in Biosynthesized Nickel Oxide nanocoatings from Cactus plant extract 15m

In this paper, nickel oxide (NiO) nanoparticles using a novel green chemistry method that
involved the application of Ethiopian cactus plant extract (Euphorbia Abyssinica) was
synthesized. The green synthesized NiO nanoparticles was then spin-coated on Cu substrate
at rotational speed (RS) of 1500 rpm. The microstructure, elementals composition, surface
morphology, of NiO nanocoating were investigated. The XRD pattern studies revealed that
the NiO Nanocoating has a face-centered cubic (FCC) structure. SEM confirm NiO
Nanocoating are uniformly distributed Nano sphere-like structure with an average particle
size of 35 – 40 nm range. AFM showed a homogeneous hillock-like structure NiO Nanocoating
with a surface roughness of 15.3 nm. Optical investigation reveals an optical band gap of
3.42 eV estimated from Tauc’s plot of UV–Vis absorption spectra. While the reflectance,
refractive index, and extinction coefficient are increased with increasing wavelength, the
absorbance value designates NiO nanocoating absorbs ~95% of the incoming solar radiation
in the UV and decreases with increasing wavelength. The bandgap energy (Eg) obtained
and the high absorptivity of the prepared nanocoatings revealed that NiO nanocoating is
more suitable for solar radiation harvesting in solar cell applications.

Speaker: Henok Gebretinsae (UNESCO UNISA ITLABS-NRF Africa Chair in Nanosciences & Nanotechnoly(U2ACN2) and NANOsciences AFrican NETwork (NANOAFNET))
• 10:30
Annealing Optimization of Graphitized Hierarchical Co3O4@CuO@NiO for Supercapacitor Electrodes 15m

Recently, carbon derivatives addition in electrodes fabrication enhanced performance of newly fabricated electrodes applied in energy storages electrode materials. We formed a composite of Co3O4@CuO@NiO and graphene oxide (GO) using hydrothermal technique. Annealed synthesized electrodes at different temperatures and examine various electrodes for supercapacitor application using three-electrode system. The Co3O4@CuO@NiO composite electrode annealed at 100 ºC demonstrates better performance compared to pristine and other temperatures. The results presented a specific capacitance of the Co3O4@CuO@NiO electrode annealed 100 ºC at 1312 F/g from cyclic voltammetry (CV) testing using 10.0 mV/s scan rate and 1258 F/g from galvanostatic charge discharge (GCD) at 1.0 A/g current density. Electrode annealed at 100 ºC also exhibited higher cycling stability of 92.5 % after 10, 000 cycles showing that annealing at 100 ºC improved electrodes properties.

Speaker: Dr Obodo Raphael Mmaduka (University of Nigeria, Nsukka)
• 10:45

F.T. Thema•1,2,3, M. Maaza1,2,

1 Botswana University of Agriculture & Natural Sciences, Gaborone-Botswana,
2 UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate
Studies, Muckleneuk ridge, PO Box 392, Pretoria, South Africa,
3 Nanosciences African Network (NANOAFNET), iThemba LABS-National Research
Foundation, 1 Old Faure Road, Somerset West, Western Cape 7129, PO Box 722, South Africa.

Corresponding author•: ftthema@gmail.com

Abstract
A simple and economical approach to synthesize Graphene Nanosheets (GNSs) via the exfoliation and intercalation of natural graphite flake material into graphene oxide (GO) following a γ-irradiation process is demonstrated. The GO forms stable colloidal dispersion in polar aprotic solvent and in suspension in N, N-dimethyl formamide (DMF) and in a homogenous phase is reduced by γ-ray induced reduction method which is environmentally friendly and cost effective. The reduction is due to the
electrons generated during the radiolysis of DMF. In this study, we report on the physical/chemical characteristics of the γ-ray induced reduced graphene oxide (γ –r GO) suspension adhered on glass substrates.

2021 International conference of the African Physical Society,
15-19 November 2021, Kigali-Rwanda

Speaker: Force Tefo Thema (N/A)
• 10:00 11:00
ePCCr Track: Keynote Lecture: B. Jones

Poster session will take place in GatherTown. You can access it by copying the link:
https://gather.town/app/txiF4xMdbAgSCtxJ/IndabaSpace

Convener: Prof. Delia Haynes (Stellenbosch University)
• 10:00
Methods of crystallization & disappearing polymorphs 1h

Numerous properties of organic molecular crystals are of interest to the solid state chemist and in particular to those interested in pharmaceutical materials science. Often the nature of polymorphism for the particular system is fundamental to development since the physical and chemical properties of each polymorph is likely to vary. Hence reproducible methods of crystallisation yielding reproducibly the same polymorph (or even an amorphous form) is essential. This is sometimes an issue when going from lab-scale methods to larger manufacturing volumes. A possibly worrying aspect is in the sometimes difficulty in reproducing a previous polymorph by what is believed to be the same experimental protocol. Is this irreproducibility a result of careless experiment, a lack of appreciation as to how accurately the essential experimental details were established or are we missing some key factors to determine which “polymorphs” may be susceptible to disappearance? I cannot at this moment promise a definitive answer to these questions! I will, however, describe what we now know – starting from the seminal review of Dunitz & Bernstein (ref. 1) published in 1995 and the more event review by Bucar, Lancaster & Bernstein (ref. 2) and some of our published work on mechanochemical observations of disappearing polymorphs for the cocrystal system of caffeine and citric acid. (ref. 3)

1. Dunitz, J. D., & Bernstein, J. (1995).Disappearing Polymorphs. Accounts of Chemical Research, 28(4), 193–200.
2. Bučar, D.-K., Lancaster, R. W., & Bernstein, J. (2015). Disappearing Polymorphs Revisited. Angewandte Chemie International Edition, 54(24), 6972–6993.
3. Hasa, D., Marosa, M., Bučar, D.-K., Corpinot, M. K., Amin, D., Patel, B., & Jones, W. (2020). Mechanochemical Formation and “Disappearance” of Caffeine–Citric-Acid Cocrystal Polymorphs. Crystal Growth & Design, 20(2), 1119–1129.
Speaker: Prof. Bill Jones (University of Cambridge)
• 11:00 11:30
AfLS: None

Ceremonial African Speaking and Calling Sticks
Opening Plenary

• 11:00 11:30
AfPS-FAMPO
• 11:00
Primary dose components of three 6 MV photon beams 15m

It is a common technique in radiotherapy treatment planning systems to simplify the calculations by splitting the radiation beam into two components: namely the primary and scattered components. The primary component is the radiation which arrives at the point of interest without having had any interactions. The scattered component is the radiation which arrives at the point of interest having undergone at least one interaction. The contributions of the two components are evaluated separately and then summed to give the dose at the point of interest. It is of vital importance to determine these components as accurately as possible, as any error will have an impact on the dose the patient receives. Usually the primary dose is obtained experimentally by extrapolating the ionization measured within the medium to zero field size. This approach offers the opportunity to obtain the primary component of dose without the need for an uncertain non-linear extrapolation.

Speaker: Christoph Trauernicht (Tygerberg Hospital and Stellenbosch University)
• 11:15
Experimental determination of the average energy and dose rate constant of the OncoSeed 6711 I-125 seed through the use of a measured spectrum 15m

I-125 seeds are regularly used in low dose-rate brachytherapy implants.
Dose calculations are done according to a protocol recommended by the American Association of Physicists in Medicine. One of the required quantities is the dose rate constant, which is defined as the ratio of the dose rate at the reference position and the air kerma strength.
In this presentation the dose rate constant was obtained through the use of a measured spectrum.

Speaker: Christoph Trauernicht (Tygerberg Hospital and Stellenbosch University)
• 11:00 11:30
ePCCr Track: Crystal Engineering

Poster session will take place in GatherTown. You can access it by copying the link:
https://gather.town/app/txiF4xMdbAgSCtxJ/IndabaSpace

Convener: Prof. Delia Haynes (Stellenbosch University)
• 11:00
DO IONIC CHARACTERS HAVE AN IMPACT ON THE QUALITY OF MOLECULAR ORGANIC CRYSTALS? 15m

The importance of organic crystals in drug development, technology advancement, and the development of materials owing to their unique properties cannot be over-emphasized. But growing good-quality crystals has been a challenge, particularly since the invention of X-ray crystallography due to the complexity that surrounds crystal formation. Synthetic chemists often have an intuitive feeling that if they use a particular molecule as a co-crystallising agent during the crystallisation process, they will get good crystals. In fact, Etter et al. state in their paper on crystal growth strategies for molecular crystals1 that inorganic salts with charged ions grow larger and higher quality crystals than neutral organic molecules. Similarly, there is an expectation that salts of organic compounds will give better crystals than their neutral counterparts. In this project, we investigate multi-component crystals (salts and co-crystals) to assess the link (if any) between the ionic characters of the components and the quality of crystals obtained experimentally.
The study reveals that the interaction energies between components in salts are greater than co-crystals, suggesting that salts are more stable than co-crystals. A similar observation was obtained for the lattice energies, the free energy of interactions, electrostatic nature, polarisation energy, and the strengths of hydrogen bond donor and hydrogen bond acceptor, which means the presence of ionic components makes these interactions stronger and thereby stabilise the multi-component crystals. However, the strength of these interactions in salts does not automatically translate into a good-quality crystal, as we observed both good and poor-quality crystals of salts and co-crystals. The mosaicity, which is an indication of a crystal’s quality, is used to classify crystals according to quality. The lattice energy, which is often used to predict the stability of crystal structure, does not correlate with the quality of crystals obtained experimentally either. So, the quality of crystals is not necessarily associated with the strength of interactions in salts or the ionic nature of the components of salts but rather a combination of different factors.

Speaker: Oluwatoyin Akerele (Stellenbosch University)
• 11:15
Crystal Engineering and Solid-Solutions: from Precessional Motion to Binary and Ternary Solid Solutions of Ionic Plastic Crystals 15m

In this talk, I will show two examples concerning the solid-state dynamic behavior and phase transition of supramolecular salts made up of globular cations and halides as counterions, and how it is possible to modulate their order-disorder transitions through the formation of crystalline solid solutions. Given the structural similarities between the salts, binary and ternary solid solutions have been thus obtained. Furthermore, the composition-dependent field of stability of the order-disorder transitions has been studied by a combination of XRD, calorimetric (TGA and DSC), and solid-state-NMR techniques.

Speaker: simone dagostino (University of Bologna)
• 11:30 11:45
Gather Town

Meet informally in the Gather Town

• 11:45 13:00
AfLS: None

Ceremonial African Speaking and Calling Sticks
Opening Plenary

• 11:45 13:00
AfPS-AMRS-ANNS
• 11:45
Brownian motion effect in nanofluids’ thermal conductivity enhancement 15m

N. Tandjigoral
1,2,•, M. Maaza1-2
1 UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate
Studies, Muckleneuk ridge, PO Box 392, Pretoria, South Africa
2 Nanosciences African Network (NANOAFNET), iThemba LABS-National Research
Foundation, 1 Old Faure Road, Somerset West, Western Cape 7129, PO Box 722, South Africa
•Corresponding author: Nene Tandjigora / sakho-nene@hotmail.fr
Abstract
•Pioneered by Choi from the US Department of Energy (DoE), nanofluids are dilute suspension
of nanoparticles in a host standard heat transfer fluid. At first glance, and because, the
additive nature of the thermal conductivity from thermodynamic viewpoint, the low thermal
conductivity of standard heat transfer fluids (mineral oil, Ethylene Glycol, water,..) not
exceeding 1 Wm−1 K−1 can be enhanced by incorporating nanoscaled particles of metals or
their oxides. Such an enhancement of thermal conductivity was predicted as early as 1906
by Maxwell followed by several theoretical models. Although these models got in some point
correct predictions, they cannot be used on nanofluids because they neglect pivotal
phenomena such as Brownian motion, Van Der Waals attractive forces of nanoparticle that
have tendency to agglomerate, the size of nanoparticles, large volume of surrounding liquid
that are not taking by these classical models. Thus, as a result the effective thermal
conductivity, keff,. This contribution reports on the critical part of the Brownian motion in the
thermal conductivity enhancement.

Keywords: Nanofluids; thermal conductivity enhancement; Brownian motion;
2021 International conference of the African Physical Society,
15-19 November 2021, Kigali-Rwanda

Speaker: Nene Tandjigora (UNISA/iThemba LABS)
• 12:00
GONFLEMENT ET TASSEMENT DES SOLS ARGILEUX DE HOUEYOGBE DANS LA DEPRESSION DE LA LAMA 15m

Les sols gonflants sont des sols de consistance variable en fonction de leur teneur en eau ; Ils créent de ce fait l’instabilité des structures qui y sont érigées. La présente étude est une contribution à l’étude du comportement mécanique des sols argileux de la commune de Houéyogbé faisant parti de la dépression de la Lama au Bénin. Elle porte sur l’influence du gonflement des argiles sur leur tassement. A cet effet, des essais œdométriques à incrément successif de charges et des essais de gonflement libre à l’œdomètre ont été réalisés sur des échantillons intacts prélevés afin de déterminer respectivement le tassement et le gonflement libre. De l’analyse des résultats des essais effectués, il ressort que les sols étudiés sont des argiles plastiques à très plastiques, surconsolidées et moyennement gonflantes. Le gonflement libre des sols influence très peu la valeur du tassement final obtenu à l’œdomètre.
Mots clés : Sols argileux, dépression de la Lama, essai œdométrique, gonflement libre.

Swelling soils are soils of variable consistency depending on their water
content; They have established the instability of the structures that are
erected there. The present study is a contribution to the study of the
mechanical behavior of clay soils of the Benin Lama depression. It is carried
out on the clay soils of the commune of Houéyogbé being part of the
depression. It deals with the influence of the swelling of clays on their
settlement. For this purpose, oedometric tests with successive increments of
charges and tests of free swelling at the oedometer were carried out on intact
samples taken by the National Center for Study and Research of Public Works
(CNERTP) in order to determine respectively settlement and free swelling.
From the analysis of the results of the tests carried out, it appears that the
studied soils of the commune of Houéyogbé are plastic clays with very plastic,
overconsolidated and moderately swelling. The free swelling of soils has very
little influence on the value of the final settlement at the oedometer.

Speaker: Mr Zodier Virtus TOHOUNGBA (Ecole Doctorale des Sciences de l'Ingénieur (ED-SDI))
• 12:15
Sustainable energy future with materials for solar collection, conversion and storage 30m

Abstract
The transition to a sustainable energy future is dependent on a clean and efficient power supply. Solar power is the most attractive clean energy source due to its abundance and numerous ways of harnessing it. Solar energy harvesting involves the use of a wide range of materials including metal oxides and halide perovskites (HaP) for conversion into hydrogen and electricity via photoelectrochemical (PEC) water splitting and photovoltaic technologies, respectively. Hematite has emerged as one of the most suitable metal oxide photocatalysts for solar hydrogen production due to their small bandgap (̴ 2.0 eV) and stability in solution. However, the major challenge limiting the use of haematite in PEC water splitting include their low conductivity, poor charge separation, and short charge carrier lifetime. Also, HaP solar cells are the fastest emerging photovoltaic technology in terms power conversion efficiency. However, their instability, and toxicity of lead and solvents are major bottlenecks blocking the commercialization of the technology. This chapter reviews the strategies that have been engaged towards overcoming the limitations of using hematite and HaP for direct conversion of solar energy into hydrogen fuels and electricity, respectively. The simultaneous engagement of strategies such as nanostructuring, doping, the formation of heterostructures, the use of co-catalyst, and plasmonic enhancement effects have shown great promise in improving the photocatalytic water splitting capabilities of hematite. Vapor methods for preparing HaP have the potential for improving their stability and eliminate the use of toxic solvents during fabrication. More research will be required for the eventual commercialization of solar hydrogen production and photovoltaic technologies using hematite and halide perovskites, respectively.

Speaker: Prof. Mmantsae Diale (University of Pretoria)
• 11:45 13:00
ePCCr Track: Inorganic Materials

Poster session will take place in GatherTown. You can access it by copying the link:
https://gather.town/app/txiF4xMdbAgSCtxJ/IndabaSpace

Convener: Seham Abdel-Aal (Cairo University, Egypt)
• 11:45

DECTRIS develops and manufactures the most accurate X-ray detectors to spark scientific breakthroughs around the world. DECTRIS systems have revolutionized X-ray detection at synchrotron beamlines with their outstanding data quality, high performance and simple operation.
Our leading synchrotron technology is also available for laboratory applications. Direct detection of X-rays in a solid-state sensor achieves the sharpest signals and the highest resolution. Eliminating dark current and readout noise enables DECTRIS detectors to reach unsurpassed signal-to-noise ratios and outperform other laboratory detector technologies.
This presentation will give an overview of the available DECTRIS X-ray detectors and their unique advantages. You will also learn how these advantages can help you in your research.

Speaker: Dr Marcus Müller (DECTRIS Ltd)
• 12:00
Characterization of the clay of SEHOUE- MASSI used for chemicall purification : case of the ponds of GBAGO ( Porto-Novo. Republic of Benin) 15m

Characterization of the clay of SEHOUE-MASSI to reduce chemical pollution of ponds

Speaker: Dr Romuald Arthur CAKPO (Faculté des Sciences et Techniques (FAST) . Université d'Abomey-Calavi (UAC). République du Bénin)
• 12:15
Effect of Cr-Bi substitution on the structural, optical, electrical and magnetic properties of strontium hexaferrites 15m

M-type hexagonal ferrite, SrFe12−2xCrxBixO19 (x=0.0{0.2) was prepared using
sol-gel auto combustion technique. X-ray diffraction (XRD), Fourier transform infra-red
(FTIR), feld emission scanning electron microscopy (FESEM), UV{Vis{NIR spectroscopy,
vibrating sample magnetometer (VSM) and impedance analyzer were respectively used to
investigate the structural, optical, electrical and magnetic properties of the synthesized materials. XRD analysis reveals the formation of single phase of M-type hexaferrite with crystallite size ranging from 33 to 42 nm. The presence of peaks at 441, 552, and 598 cm−1 in the
FTIR spectra indicate the formation of hexaferrite phase. FESEM images shows agglomerated particles having almost hexagonal shapes. The band gap of the material lies between
1.71 and 1.96 eV. The saturation magnetization and remanence enhances with increasing
Cr3+-Bi3+ concentration. The dielectric constant and dielectric loss tangent decrease with
increase in frequency while AC conductivity shows an increase at higher frequencies.

Speaker: Dr Carol Trudel Tchouank Tekou (Lovely Professional University)
• 12:30
Crystal characterization and application of a new vanado-phosphate material 15m

A new vanadium phosphate, Li(C4N2H11)2[(PO4)4(VO)3], has been hydrothermally synthesized and structurally characterized by single crystal x-ray diffraction. The hybrid compound crystallizes in the orthorhombic system, space group Pna21, with the following parameters (Å): a=14.6207, b=8.709, c=17.6208. The crystal packing, consisting of layers parallel to bc plane, is made of alternating rings of VO5, VO6 and PO4 polyhedral sharing vertices via oxygen atoms. The Li-ions are located in the eight membered rings, exactly at the opening window of the layers, while the protonated organic molecules reside between the interlayer space and interact with the inorganic moiety via hydrogen bonds in a three-dimensional arrangement. its thermal behavior consists mainly of the loss of the organic part leading thus to the formation of vanadium pyrophosphate system. The hybrid material exhibits efficiency in catalytic oxidation and degradation of methylene blue dye.

Speaker: Najlaa Hamdi (FSDM)
• 12:45
Local structure of energy materials and beyond with synchrotron data 15m

Devices for sustainable energy applications are notoriously complex in structure, with heterogeneities and structures on different lengthscales. This requires characterization tools that can study material structure on different lengthscales with high precision. This is possible with intense x-rays and advanced computational and data analytical methods. I will describe with examples some recent developments in local structure analysis that gives critical information about catalysts for solar fuel conversion, battery electrode materials and even pharmaceuticals

Speaker: Simon Billinge (Columbia University)
• 13:00 14:00
Gather Town

Meet informally in the Gather Town

• 14:00 15:00
Plenary: by Dr. Bjorn von der Heyden & Dr. Julien Benoit / Session chair : Prosper Ngabonziza
• 14:00
Earth sciences at an African Light Source 30m

The Earth Sciences represent a broad array of sub-disciplines, all of which can be advanced significantly through dedicated studies utilising synchrotron X-rays. The present conference submission provides a review of how synchrotron X-rays have been used in previous studies of African earth science samples, and provides suggestions of what the synchrotron needs are for African earth science community.

Speaker: Bjorn von der Heyden (Stellenbosch University)
• 14:30
How SRCT shed light on the brain, sense organs and physiology of our pre-mammalian ancestors 30m

All modern mammals are descended from the pre-mammalian therapsids, colloquially referred to as "mammal-like reptiles". It has long been assumed that these mammalian ancestors were essentially reptilian in their biology and behaviour, and one of the most influential and pioneering papers on their palaeoneurology stated in 2011 that they "possessed low-resolution olfaction, poor vision, insensitive hearing, coarse tactile sensitivity, and unrefined motor coordination". The use of Synchrotron scanning by our team at the University of the Witwatersrand has brought new data that nuances this view.
Our research has brought new evidence that palaeoneurological and behavioural traits previously considered as typically mammalian, such as whiskers, nocturnality, enhanced olfaction, lactation, complex social interactions and an enlarged brain evolved before the very origin of mammals. Others, such as a coiled cochlea, already started evolving in cynodonts, the most direct ancestors of mammals among "mammal-like reptiles".
Refined sense organs likely predated the origin of mammaliaforms by millions of years, possibly in correlation with the evolution of endothermy and adaptation to nocturnality as the archosaurs were becoming dominant over terrestrial ecosystems.

Speaker: Julien Benoit (Evolutionary Studies Institute, WITS, Johannesburg)
• 15:00 16:00
AfLS Track: Round Table Discussion on “Paving the way for an Africa-SESAME Partnership” / Session Chair: Christine Darve
• 15:00
Round Table Discussion on “Paving the way for an Africa-SESAME Partnership” 1h

The SESAME synchrotron radiation facility in the Middle East has been in operation since 2017. Two new state-of-the-art beamlines for micro-tomography (BEATS) and soft X-ray science (HESEB) will be added in 2022 almost doubling the existing portfolio of three operational beamlines. SESAME as an operational facility will bring strong opportunities in research and training to the African scientific communities to boost the pan-African Light Source initiative AfLS. We therefore propose a round table discussion as a special session during the 2021 joint AfLS virtual meeting to review these opportunities and to discuss how an Africa-SESAME partnership could be forged.
Suggested round table panelists (all panelists tbc):
• Simon Connell, Chair of the Executive Committee, AfLS
• Andrea Lausi, SESAME
• Ed Mitchell, ESRF
• Kirsi Lorenz, Cyprus Institute
• Gihan Kamel, SESAME

Speakers: Dr Andrea Lausi (SESAME) , Dr Edward Mitchell (ESRF) , Dr Gihan Kamel (SESAME Light Source) , Prof. Simon Connell (University of Johannesburg) , Dr Christine Darve (European Spallation Source)
• 15:00 16:00
AfPS-AMRS-ANNS
• 15:00
Thermal conductivity of Chalcogenides Alloys for energy and non-volatile memory applications 15m

Chalcogenide alloys continue to receive widespread interest due to their excellent correlated properties essential for thermoelectric and energy storage in non-volatile based memory devices. In this work we present attempts at determination of the thermal conductivity using Surface Brillouin scatter and Time domain thermal reflectance in the various structural phases. Thin films of chalcogenide alloys formed from the Pseudo-binary tie line and eutectic phases have been grown using RF magnetron sputtering on (001) Si substrates. Using the procedure of Cahill’s random walk model on the acoustic phonon velocities we estimate the minimum thermal conductivity of the disorder phase to be k < 0.5 W/m.K. Our values are in close agreement with those measured by TDTR in the disordered phase. A low thermal conductivity value is essential for thermal management in Phase change random access memory as well as for thermoelectric applications.

Speaker: Daniel Wamwangi (School of Physics, Materials Physics Research Institute, University of the Witwatersrandersity)
• 15:15
Room Temperature Hydrogen gas sensing of nanoscaled 1-D VO2 15m

Mott-type VO2 oxide nanobelts are demonstrated to be effective hydrogen gas sensors at
room temperature. These nanobelts, synthesized by hydrothermal process and exhibiting the
VO 2 (A) crystallographic phase, display room temperature H 2 sensitivity as low as 0.17 ppm.
The nanobelts (ultralong belt-like) nanostructures could be an ideal system for fully
understanding dimensionally confined transport phenomena in functional oxides and for
building functional devices based on individual nanobelts.

Speaker: BOITUMELO MABAKACHABA (UWC/ ITHEMBA LABS)
• 15:30
Smart nanomaterials for green air conditioning & concentrated solar power applications 15m

M. Maaza1-2
1UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, PO Box 392,
Muchleuneuck, College of Graduate Studies, University of South Africa, Pretoria-South Africa ,
2Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation,
PO Box 722, Somerset West, Western Cape Province, South Africa
Prof. Malik Maaza: Maaza@tlabs.ac.za
Abstract
•The Global energy demand for air conditioning is expected to triple by 2050, requiring new
electricity capacity the equivalent to the combined electricity capacity of the US, the EU
and Japan today. The global stock of air conditioners in buildings is expected to grow to 5.6
billion by 2050, up from the current1.6 billion which almost corresponds to 10 new ACs sold
every second for the next 30 years. In line with the SDGs, Smart nano coatings such as those
based on thermochromic VO2 could assist in addressing such a challlenge in minimizing the
energy load. Biomimicking the Gemsbock heat management approach, this family of VO2
based nanomaterials exhibit 1st order Mott phase transition. They are semiconductor and
metallic at low & high temperature respectively. Hence Infrared transparent & infrared
opaque at low & high temperatures respectively. Consequentially, Solar heat dynamic
windows coated with such VO2 temperature responsive solar heat nanocoatings allow smart
active solar heat management & green air-conditioning. Likewise, it is demonstrated that
such VO2 materials are multifunctional with potential applications in ultrafast optoelectronics
and femtosecond nanophotonics.In addition, in form of nanosuspensions i.e nanofluids can
exhibit an enhanced thermal conductivity allowing an improved thermal transfer of the
coolant fluid in Concentrated Solar Power (CSP) based systems and henceforth working in
tandem with CSP Selective Solar Absorbers.This contribution is intending to highlight the
versatility of theVO2 based smart nanocoatings for green air-condioning & novel approach
for the engineering of nanofluids & selective solar absorbers for CSP technolo

Speaker: Prof. Maaza Malik (UNESCO UNISA ITLABS/NRF Africa Chair in Nanosciences & Nanotechnologies)
• 15:45
Molecular dynamics simulation of Ti32 cluster 15m

There has been a renewed interest in the experimental and theoretical studies of atomic molecular clusters. Small clusters exhibit physical and chemical properties that are often different from the bulk phase due to the large fraction of surface atoms. However, not much has been done on the thermal agitation of the smaller transition metal clusters particularly, smaller clusters of titanium metal. Molecular dynamics simulations were carried out for Ti32 cluster using Gupta potentials for metal-metal interactions potentials. The classical molecular dynamics simulation software (DL_POLY) was used to investigate the thermal agitation on Ti32 metal cluster. The dynamical properties were interrogated by subjecting the clusters to various temperature range of 300K – 2400K. The radial distribution functions (RDFs), diffusion coefficient, density profiles and Mean square displacement (MSD) were examined to investigate the structural changes as the temperature is increased. It was found that the solid-solid phase transitions reasonably correspond with the experimental data. The potential energy displayed liquid-like features at 2000 K. Furthermore, the RDFs and density profile peaks decreases as the temperature is increased. The density profiles depicted the solid-like features indicated by the distinct peaks at lower temperatures.

Speaker: Mr Tshegofatso Michael Phaahla (University of Limpopo)
• 15:00 15:45
ePCCr Track: Structural Chemistry & Inorganic Materials

Poster session will take place in GatherTown. You can access it by copying the link:
https://gather.town/app/txiF4xMdbAgSCtxJ/IndabaSpace

Convener: Bernard Owaga (University of KwaZulu-Natal)
• 15:00
The guanidinium t-diaqua-bis(oxalato) chromate(III) dihydrate complex: synthesis, crystal structure, EPR spectroscopy and magnetic properties 15m

A new salt (CH6N3)[t-Cr(C2O4)2(H2O)2]•2H2O (1) (CH6N3+ = guanidinium cation) has been synthesized and characterized by single-crystal X-ray diffraction, FT-IR and UV–Vis spectroscopies, elemental and thermogravimetric analyses. In the crystal structure of (1), the chromate(III) ion lies on an inversion center in the form of an elongated octahedron. The coordination sphere consists of four oxygen atoms of two chelating oxalato ligands in the equatorial plane and two axial oxygen atoms of water ligands. The structural feature of focal interest in the structure of (1) is the formation of pillars of [Cr(C2O4)2(H2O)2]− complex anions and CH6N3+ guanidinium cations, with the next-neighbor cations rotated by an angle of 60° relative to each other. O–H•••O and N–H•••O hydrogen bonds play an important role in the construction of the three-dimensional network. The electron paramagnetic resonance (EPR) and magnetic properties of (1) have also been investigated.

Speaker: idelle KAMGA NONO
• 15:15
Structural, magnetic and optical properties study of tellurium–based: Sr3-xPbxFe2TeO9 (0 ≤ x ≤ 2.25) double perovskites 15m

Materials family of A3B’2B’’O9 (A = alkaline–earth metal ions with valence +2, B’ and B’’= transition metal ions with valences +3 and +6 respectively) were subjected to extensive studies, and have attracted significant interest owing to their physical properties and technological applications. The discovery of colossal magnetoresistance (CMR) in the ordered A2B’B’’O6 double perovskite oxides has given rise to many recent research [1–3].
Polycrystalline samples of the series of triple perovskites Sr3−xPbxFe2TeO9 (0 ≤ x ≤ 2.25) were synthesized using solid state reaction [4]. These materials have been studied by a combination of XRPD, Mössbauer spectrometry, Raman and UV–Vis spectroscopies. The crystal structures were resolved by the Rietveld refinement method, and revealed that this Sr3−xPbxFe2TeO9 (0 ≤ x ≤ 2.25) system shows one space group change from tetragonal I4/m (0 ≤ x ≤ 1) to another tetragonal form I4/mmm (1.25 ≤ x ≤ 1.88) and a second transition to hexagonal R-3m (2.08 ≤ x ≤ 2.25). The valence state of iron in the Fe site was determined to be Fe(III) by Mössbauer spectrometry, which also revealed two sites in a concordance with the XRPD measurements. 57Fe Mössbauer spectra measurements show paramagnetic and magnetic ordering behaviors. The observed Raman spectra as a function of composition show obvious changes on the positions (wavenumbers), the FWHM and the intensities of the modes confirming the phase transformations observed by the XRPD results. These structural transitions led to a distinct change in the optical band gap energy, varying from 2.14 to 1.85 eV.
References:
[1] K.I. Kobayashi, T. Kimura, H. Sawada, K. Terakura, Y. Tokura. Nature, 1998, 395, 677–680.
[2] M. García–Hernández, J.L. Martínez, M.J. Martínez–Lope, et al., Phys. Rev. Lett., 2001, 86, 2443.
[3] W.R. Branford, S.K. Clowes, Y.V. Bugoslavsky, et al., J. Appl. Phys., 2003, 94(7), 4714–4716.
[4] A. El Hachmi, F. El Bachraoui, S. Louihi, Y. Tamraoui, S. Benmokhtar, et al., J. Inorg. Organomet. Polym., 30, 1990–2006 (2020). https://doi.org/10.1007/s10904-020-01446-4
Keywords: Phase transitions; X-ray diffraction; Mössbauer spectrometry; Raman spectroscopy; UV– Vis spectroscopy

Speaker: Dr Abdelhadi El Hachmi (Laboratoire Rayonnement Matière et Instrumentation, S3M, FST, University Hassan 1er, 26000 Settat, Morocco)
• 15:30
X-ray and Electron diffraction instruments from Rigaku Oxford Diffraction 15m

The latest range of Rigaku Oxford Diffraction instrument configurations for Chemistry and structural biology will be summarised, and illustrated with a number of particular example applications.
The XtaLAB Synergy platform with microfocus or rotating anode sources on one side and a series of Hybrid Photon Counting (HPC) X-ray area detectors on the other side of the four-circle goniometer allows for versatile configurations perfectly adapted to the researcher’s needs. These systems can be further equipped with the sample changing robot (XtaLAB Synergy Flow), an Intelligent Gonoimeter Head (IGH) for automated crystal centering, the plate scanning device XtalCheck-S.
Furthermore, our X-ray diffraction instruments are complemented by the new XtaLAB Synergy-ED – a fully integrated electron diffractometer, creating a seamless workflow from data collection to structure determination of three-dimensional molecular structures. The XtaLAB Synergy-ED is the result of an innovative collaboration to synergistically combine our core technologies: Rigaku’s high-speed, high-sensitivity photon-counting detector (HyPix-ED) and state-of-the-art instrument control and single crystal analysis software platform (CrysAlisPro for ED), and JEOL’s long-term expertise and market leadership in designing and producing transmission electron microscopes.

Speaker: James Gordon (Rigaku SE)
• 15:45 16:00
Break 15m
• 16:00 17:00
Plenary: Closing Plenary / Session chair : Tabbetha Dobbins
• 16:00
XTechLab 30m

Virtual Tour of XTechLab

Speaker: Marielle AGBAHOUNGBATA (Semi City)
• 16:30
Closure 30m

Prizes

Three wise sages (1 / track)
1. Wise Young person.
2. Wise Gentleman