Effect of Mechanical Milling and Cold Pressing on Co Powder

Absract: Cobalt (Co) is a transition metal used in electronics, magnetic recording [1], and hard materials [2–4]. Through thermal [5] and mechanical treatment [6–9], Co metal undergoes the allotropic HCP to FCC phase transformation. The current literature shows that metastable FCC phase is induced by ball milling (BM) [6], cold pressing [10], and thermal treatments [11]. It has been shown in the previous investigations that Co milled with W, V, and C powders forms the complex FCC Co-rich carbide with large lattice parameters [12]. Apart from the FCC phase, Co-based alloys undergo amorphization via electrodeposition [13, 14] and mechanical alloying (MA) [15–17] and during irradiation processes [18, 19]. It is worth noting that in the case of milling, the XRD peaks of nonmetallic elements such as Si in a mixture with Co vanish rapidly when subjected to BM and ultimately lead to amorphization [17]. Similar behaviour occurs when a mixture of Co and metallic elements is subjected to milling [15, 16, 20]..

Effect of Mechanical Milling and Cold Pressing on Co Powder

Absract: Cobalt (Co) is a transition metal used in electronics, magnetic recording [1], and hard materials [2–4]. Through thermal [5] and mechanical treatment [6–9], Co metal undergoes the allotropic HCP to FCC phase transformation. The current literature shows that metastable FCC phase is induced by ball milling (BM) [6], cold pressing [10], and thermal treatments [11]. It has been shown in the previous investigations that Co milled with W, V, and C powders forms the complex FCC Co-rich carbide with large lattice parameters [12]. Apart from the FCC phase, Co-based alloys undergo amorphization via electrodeposition [13, 14] and mechanical alloying (MA) [15–17] and during irradiation processes [18, 19]. It is worth noting that in the case of milling, the XRD peaks of nonmetallic elements such as Si in a mixture with Co vanish rapidly when subjected to BM and ultimately lead to amorphization [17]. Similar behaviour occurs when a mixture of Co and metallic elements is subjected to milling [15, 16, 20]..

Comparison of metastable phases induced by heat treatment of unmilled and milled cobalt powders

Abstract The sintered and water quenched compact samples were prepared from unmilled and milled Co powders. Characterisation was performed by differential scanning calorimetry, scanning electron microscopy and X-ray diffraction techniques. Several metastable phases were obtained upon sintering and quenching. However, more metastable phases were induced on quenching the milled–sintered samples due to introduction of large number of defects in addition to those induced by milling. Micro hardness values for unmilled sintered samples were the lowest while those of 30 h milled-sintered samples were the highest. The current study reveals that the two FCC metastable phases obtained by quenching unmilled powder were similar to those found in milled–sintered samples

A Training Course for Psychologists: Learning to Assess (Alleged) Sexual Abuse Among Victims and Perpetrators Who Have Intellectual Disabilities

People with intellectual disabilities (ID) are at greater risk of being a victim of sexual abuse and may also be more predisposed to perpetrating sexual abuse. Although the prevalence of sexual abuse among people with ID is difficult to determine, it is clear that there are serious consequences for both victims and perpetrators, and professional support is needed. Psychologists play an important role in the assessment of sexual abuse in both victims and perpetrators and require specific knowledge and skills to execute the assessments. We therefore developed a training course for psychologists aimed at increasing their (applied) knowledge of sexual abuse and the related assessment process in people with ID. In a five-day training course, sessions focusing on theories about diagnostic models were combined with sessions focusing on the assessment of sexual abuse of victims and perpetrators. The effectiveness of the training course was determined in terms of (applied) knowledge via the administration of a study-specific questionnaire including a hypothetical case vignette before, immediately after, and six months after completion of the course. The results show that the knowledge of the psychologists related to sexual abuse and the assessment process for sexual abuse increased significantly, and remained above pre-test level at six-month follow-up. These results are promising, but more research is needed to see if the increased (applied) knowledge in turn leads to application in practice and better care for both victims and perpetrators

Establishing African genomics and bioinformatics programs through annual regional workshops

The African BioGenome Project (AfricaBP) Open Institute for Genomics and Bioinformatics aims to overcome barriers to capacity building through its distributed African regional workshops and prioritizes the exchange of grassroots knowledge and innovation in biodiversity genomics and bioinformatics. In 2023, we implemented 28 workshops on biodiversity genomics and bioinformatics, covering 11 African countries across the 5 African geographical regions. These regional workshops trained 408 African scientists in hands-on molecular biology, genomics and bioinformatics techniques as well as the ethical, legal and social issues associated with acquiring genetic resources. Here, we discuss the implementation of transformative strategies, such as expanding the regional workshop model of AfricaBP to involve multiple countries, institutions and partners, including the proposed creation of an African digital database with sequence information relating to both biodiversity and agriculture. This will ultimately help create a critical mass of skilled genomics and bioinformatics scientists across Africa.</p

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Link between structural and mechanical stablility of fcc- and bcc-based ordered Mg-Li alloys

The first principles pseudopotential calculations based on the Perdew-Burke-Ernzerhof (PBE) form of generalized gradient approximation (GGA) within density functional theory (DFT) have been utilized to investigate the structural and elastic properties of cubic-based Mg-Li alloys. The heats of formation and elastic moduli were used in predicting structural stability profile, and their results are consistent with each other. In terms of phase stability, an interesting correlation between the calculated tetragonal shear modulus (C) and formation energy of corresponding bcc and fcc ordered compounds relative to hcp Mg and Li lattices is drawn. The predicted stability trend due to structural energy difference was further confirmed by electronic structure calculations based on Jones-type analysis