Statistical analysis of wind speed for electrical power generation in some selected sites in northern Nigeria

In this paper, statistical analysis is carried out to determine the accurate frequency distribution that fits wind speed data. The frequency distributions used include Weibull, Rayleigh and Gamma distribution functions. The performances of the probability distributions are based on the error evaluations between the predicted and the theoretical wind power densities of the site. The Results show that Weibull distribution modelled the wind speed better compared to other distribution functions. According to the European Wind Energy Association, most of the sites are suitable for the generation of electrical energy. Also, the results have shown that Jos, Kano and Minna fall in class 4 and therefore suitable for both off grid and grid connected modes. In addition, the effects of c and k parameters on the probability distribution functions have been presented.Keywords: Wind speed - probability - density function – wind energy conversion system- statistical analyse

Crystal structure and spectral of new hydrazine-pyran-dione derivative: DFT enol↔hydrazone tautomerization via zwitterionic intermediate, hirshfeld analysis and optical activity studies

A novel functionalized Schiff base derivative, (E)-3-(1-(2-(9H-fluoren-9-ylidene)hydrazineyl)ethylidene)-6-methyl-2H-pyran-2,4(3H)-dione, was synthesized via subsequent condensation/tautomerization processes in a high yield. The product was fully characterized using NMR, FT-IR, and single-crystal XRD; the results of DFT simulations were in respectable agreement with crystallographic data. To elucidate the isomerization, the enol↔hydrazinium tautomerism has been pursued theoretically, suggesting an intramolecular single proton transfer (SPT) from enol (O ….H) to the closest NC unit, giving the hydrazine (N–H) via [N+—H ….O−] S (6) zwitterionic intermediate. The results of Hirshfeld surface analysis (HSA) and Molecular electronic potential (MEP) were matching the experimental XRD results. Since a number of hydrogen bonding groups, C–H …. π, and π …. π-stacking interactions were detected experimentally. The optical properties of the desired compound were experimentally and theoretically figure out.The authors acknowledge the Algerian Directorate General for Scientific Research and Technological Development and the Algerian Ministry of Higher Education and Scientific Research, for support of this work. Researchers Supporting Project (RSP-2020/78), King Saud University, Riyadh, Saudi Arabia

Ab initio Calculations of Multilayer Relaxations of Stepped Cu Surfaces

We present trends in the multilayer relaxations of several vicinals of Cu(100) and Cu(111) of varying terrace widths and geometry. The electronic structure calculations are based on density functional theory in the local density approximation with norm-conserving, non-local pseudopotentials in the mixed basis representation. While relaxations continue for several layers, the major effect concentrates near the step and corner atoms. On all surfaces the step atoms contract inwards, in agreement with experimental findings. Additionally, the corner atoms move outwards and the atoms in the adjacent chain undergo large inward relaxation. Correspondingly, the largest contraction (4%) is in the bond length between the step atom and its bulk nearest neighbor (BNN), while that between the corner atom and BNN is somewhat enlarged. The surface atoms also display changes in registry of upto 1.5%. Our results are in general in good agreement with LEED data including the controversial case of Cu(511). Subtle differences are found with results obtained from semi-empirical potentials.Comment: 21 pages and 3 figure

Design and field procedures for the clinical reappraisal of the Composite International Diagnostic Interview version 3.3 in Qatar's national mental health study

Background The Composite International Diagnostic Interview (CIDI) has been clinically reappraised in several studies conducted mainly in the US and Europe. This report describes the methodology used to conduct one of the Middle East's largest clinical reappraisal studies. The study was carried out in conjunction with the World Mental Health Qatar—the first national psychiatric epidemiological study of common mental disorders in the country. This study aimed to evaluate the diagnostic consistency of core modules of the newly translated and adapted Arabic version of the CIDI 5.0 against the independent clinical diagnoses based on the Structured Clinical Interview for DSM-5 (SCID-5). Methods Telephone follow-up interviews were administered by trained clinicians using the latest research edition of the SCID for DSM-5. Telephone administered interviews were key in the data collection, as the study took place during the COVID-19 pandemic. Results Overall, within 12 months, 485 interviews were completed. The response rate was 52%. Quality control monitoring documented excellent adherence of clinical interviews to the rating protocol. Conclusions The overall methods used in this study proved to be efficient and effective. For future research, instrument cultural adaptation within the cultural context is highly recommended

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

XRD/HSA, noncovalent interactions and influence of solvent polarity on spectral properties of dithiocarbazate schiff base and its cis-Cu(II) complex: Experimental and theoretical studies

A N,S-bidentate ligand (LH) was synthesized via the condensation of S-benzyldithiocarbazate with acetophenone. The produced Schiff base ligand was reacted with a copper(II) salt to yield a neutral cis-Cu(II) complex. The influence of solvent polarity on spectral properties were demonstrated for the new complex in different organic solvents. The global reactivity parameters were estimated by means of energy values of the frontier molecular orbitals. Both the desired LH and its complex have been characterized by XRD-crystal analysis. In solid state the LH exists in a thione tautomeric form, while the deprotonated form of is chelated to the Cu(II) center through neutral nitrogen of azomethine and ionic sulfur of thiol, giving rise to tetrahedrally distorted square planar geometry around the metal center, in which the two ligands coordinated in cis-configuration. The noncovalent interactions were evaluated via Hirshfeld surface analysis (HSA), reflecting the presence of four position of short contacts for both the free ligand and its complex. Moreover, the formation of hydrogen bonds of the types NH⸱⸱⸱S=C and CH⸱⸱⸱S=C were observed in the ligand structure, while H⸱⸱⸱Caromatic interactions were perceived in both structures of the ligand and complex, approved by the XRD-packing results

Effect of loading methods on the performance of hierarchical porous carbon/sulfur composites in lithium sulfur batteries

Lithium-sulfur batteries have shown increasing promise for high energy densities and reduced costs. Facile sulfur loading techniques demonstrate a critical way to achieving high dispersions of sulfur in the host's matrix, improving conductivity and simultaneously decreasing the active mass loss from the cathode. Here we investigate the effect of sulfur loading methods on the electrochemical performance of porous carbon/sulfur composites containing approximately 70 wt% sulfur. Three different loading techniques are tested, including one-step molten sulfur impregnation (155°C), two-step molten sulfur impregnation (155°C + 300°C) and a sulfur organic solution impregnation, in which the entire microporous volume of carbon is filled by sulfur. It is found that the simple sulfur organic solution impregnation method is the most effective in enhancing the electrochemical performance of the hierarchical porous carbon/sulfur composite cathode in the lithium-sulfur battery system, due to the weaker interaction occurring between the sulfur and microporous carbon. Our work demonstrates the impact of sulfur loading method on the electrochemical performance of lithium-sulfur batteries, which offers new insights into the preparation technology of electrodes

Synthesis, physicochemical, thermal, and XRD/HSA interactions of mixed [Cu(Bipy)(Dipn)](X)2 complexes: DNA binding and molecular docking evaluation

Two water-soluble dicationic complexes, [Cu(bipy)(dipn)](BF4)2 (1) and [Cu(bipy)(dipn)](NO3)2 (2) (bipy = 2.2-bipyridine and dipn = dipropylenetriamine), were synthesized in high yields. The desired complexes were characterized by CHN-EA, UV–Vis, SEM, EDS, FT-IR, TGA, and XRD. The single-crystal XRD of [Cu(bipy)(dipn)](BF4)2 reflected that Cu(II) complex is formed in a distorted square pyramid configuration. The Hirshfeld surface analysis (HSA) confirmed more powerful atom–atom interaction, the hydrogen bonding in H…F, supporting the outcome of XRD. The influences of the CT-DNA/complexes were gathered by viscosity, CV, and electronic absorption measurements. The estimated binding constants (Kb) for 1 and 2 were 4.5 × 104 and 3.4 × 104 M−1, respectively. Complex 2 revealed slightly poorer DNA binding capability than 1. Eventually, the molecular docking of [Cu(bipy)(dipn)]+2 species was evaluated and demonstrated employing 1BNA-DNA segment.The authors appreciate the Deanship of Scientific Research at King Saud University for funding this research work through grant # RG-1440-141