109 research outputs found

    Correlations between Work Environment, Affective, Normative, and Continuance Commitments of Library Personnel in Public University Libraries in South-West Nigeria

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    Abstract Personnel commitment to their organisations on an emotional, normative, and long-term basis is crucial to achieving organisational goals and objectives. Working circumstances for employees in any business, particularly university libraries are crucial to achieving these levels of dedication. The impact of the work environment on the affective, normative, and long-term commitments of library staff in Nigeria\u27s South-West area was investigated in this paper. A total of 427 people participated in the study. The findings revealed that the work environment is related to affective commitment (R2 =.014; p.05), normative commitment (R2 =.004; p.05), continuance commitment (R2 =.033; p.05), and the entirety of organisational commitment (R2 =.021; p.05) of library personnel in government-owned university libraries in Nigeria\u27s South-West. As a result, the discussion concluded that the work environment is critical in ensuring and maintaining library personnel\u27s dedication to their university libraries. It was suggested that the management of the libraries offer a pleasant working environment for library employees. As a result, organisational commitment would improve a positive working environment in all aspects

    Performance Improvement of Air-cooled Battery Thermal Management System using Sink of Different Pin-Fin Shapes

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    One of the most important influences on battery safety, capacity, and cell ageing is heat generation and temperature inhomogeneity, which cause unbalanced ageing, resulting in cell performance decline. A well-developed temperature management module is required to avoid such undesirable actions. In this study, an air-cooled temperature management module was developed by coupling a unique heat sink of different pin-fin geometries/shapes to prismatic Li-ion cells and a 3D transient analysis was conducted to simulate the cooling performance of this heat sink under the effect of inlet airflow velocities and temperatures at a discharge rate of 2C for three cases. The results in the form of maximum temperature and temperature homogeneity inside the battery were derived and compared to the commonly used circular pin-fin heat sink. The overall result indicates that case 2, which consists of uniform height, shows better promise than others, taking into consideration the geometry employed. After 600 s and at a constant inlet air velocity of 0.412 m/s across a range of 20 oC to 35 oC, it was found that this heat sink performed better, providing an average of 1.87% and 1.93% improvement in temperature homogeneity and battery maximum temperature, respectively. Also, at a constant inlet air temperature of 27 oC across the range of inlet air velocity of 0.206 m/s to 0.824 m/s, this heat sink provides an average of 1.77% and 0.27% improvement in temperature homogeneity and battery maximum temperature, respectively. Doi: 10.28991/ESJ-2022-06-04-013 Full Text: PD

    YPL260W, a high-copy suppressor of a copper-sensitive phenotype in yeast, is linked to DNA repair and proteasome function

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    The ubiquitin–proteasome system directly impacts the metabolism of heavy metals and yeast has become an important model in understanding this interplay. We demonstrate that yeast mutants with defects in proteasome function are able to tolerate elevated levels of copper. In the course of our analysis, we isolate a yeast mutant that not only negates this copper tolerance in proteasome mutants, but renders yeast exquisitely sensitive to this metal. To better understand the nature of the defect, we carry out a plasmid-based genetic screen to identify high-copy suppressors of this strong copper sensitivity. We identify four genes not previously known to be associated with copper metabolism: CDC53, PSP1, YNL200C, and YPL260W. The latter is a highly conserved fungal gene of no known function. Here, we undertake the first characterization of YPL260W. We demonstrate YPL260W to have a role in bleomycin tolerance with links to DNA repair and proteasome function

    RELATIONSHIP BETWEEN DEBT RATIO AND FINANCIAL PERFORMANCE OF NIGERIAN QUOTED COMPANIES

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    This study examined the relationship between debt ratio and financial performance of selected Nigerian quoted. This research work also examined whether asset turnover is related firm financial performance as well as whether asset tangibility is related firm financial performance. Data for the period of five years (2011-2015), sourced from the annual reports of the quoted companies was used in carrying out the analysis. The variable used werey debt ratio , assets turnover, assets tangibility, and financial performance (i.e. profitability) is proxied by return on assets.STATA software was engaged in performing the correlation and regression analysis. The study detected that from the regression analysis that debt ratio and financial performance are positively and significantly related. The result also revealed that asset turnover and financial performance are negaitively and but not significantly related whlie assets tangibility and financial performance are positively and significantly related

    A comprehensive study on compositional and structural changes in 45S5 bioglass products exposed to simulated body fluid

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    The interaction of fully dense 45S5‐bioglass derived samples produced by Spark Plasma Sintering (SPS) with simulated body fluid (SBF) solution was investigated in detail taking advantage of the Rietveld refinement method to quantitatively evidence the corresponding microstructural and compositional changes. It is observed that, when the original amorphous nature is mostly (75 wt%) preserved in the material during sintering (550°C, 2 minutes), the resulting specimens dissolve faster and determine relatively higher pH increase and ions release in the SBF solution. Correspondingly, a relatively lower amount of hydroxycarbonate apatite (HCA) is formed on their surface. In contrast, a more extensive apatite layer with trabecular structure is generated within 3 days storage on the surface of fully crystallized samples obtained at 600°C by SPS, which only consists of Na–Ca silicate grains (20 nm). Moreover, as the sintering temperature and dwell time were increased to 700°C and 20 minutes, respectively, a rhenanite‐like phase was also formed (about 15 wt%), other than crystallites growth to 90 nm. Interestingly, the presence of rhenanite provides a beneficial contribution for the production of the HCA layer, which was found the largest for this system when considering storage periods of 7 and 14 days, respectively.Regione Autonoma della Sardegna (Italy). Grant Number: CUP n. F71J1100107000

    Assessment of chemical species of lead accumulated in tidemarks of human articular cartilage by X-ray absorption near-edge structure analysis

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    Lead is a toxic trace element that shows a highly specific accumulation in the transition zone between calcified and non-calcified articular cartilage, the so-called ‘tidemark’. Excellent agreement has been found between XANES spectra of synthetic Pb-doped carbonated hydroxyapatite and spectra obtained in the tidemark region and trabecular bone of normal human samples, confirming that in both tissues Pb is incorporated into the hydroxyapatite crystal structure of bone. During this study the µ-XANES set-up at the SUL-X beamline at ANKA was tested and has proven to be well suited for speciation of lead in human mineralized tissue samples

    A mineralogical study in contrasts: highly mineralized whale rostrum and human enamel

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    The outermost enamel of the human tooth and the rostrum of the whale Mesoplodon densirostris are two highly mineralized tissues that contain over 95wt.% mineral, i.e., bioapatite. However, the same mineral type (carbonated hydroxylapatite) does not yield the same material properties, as revealed by Raman spectroscopy, scanning electron microscopy, electron microprobe analysis, and synchrotron X-ray diffraction analysis. Overall, the outermost enamel of a tooth has more homogeneous physical and chemical features than the rostrum. Chemical comparison of rostrum and enamel shows bioapatite in the rostrum to be enriched in Na, Mg, CO3, and S, whereas the outermost enamel shows only a slightly enriched Cl concentration. Morphologically, mineral rods (at tens of μm scale), crystallites and prisms (at μm and sub-μm scale), and platelets (at tens of nm scale) all demonstrate less organized texture in the rostrum than in enamel. Such contrasts between two mineralized tissues suggest distinct pathways of biomineralization, e.g., the nature of the equilibrium between mineral and body fluid. This study illustrates the remarkable flexibility of the apatite mineral structure to match its chemical and physical properties to specific biological needs within the same animal or between species.The work was partially funded by NIH grant 1R21AR055184-01A2 and SRF for ROCS, SEM

    Evaluation of a hybrid solar power system as a potential replacement for urban residential and medical economic activity areas in southern Nigeria

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    A hybrid solar power system (HSPS) is an alternate method of supplying electricity that can reduce fuel usage while maintaining power supply security. In this study, the efficiency of HSPS, which consists of Grid Supply (GS), Diesel Power Generation (DPG), Solar-Photovoltaic (SPV), and Battery Storage (BS) systems, was evaluated in two economic activity areas (EAAs) in Southern Nigeria. The cross-sectional research design was used, and the research was based on Behera's energy-led growth theory. Urban-residential and Health were the EAAs considered and chosen using a stratified random sample technique. Southern Nigerian states of Oyo and Lagos provided the samples, which were combined and used for the study. Electricity consumption was calculated using electricity load demand for the two EAAs from 2008 to 2017. For each EAA, an Integrated Renewable Energy Mini/Microgrid Model (IREMMM) based on power load demand and solar irradiation was constructed. Levelized Cost of Electricity (LCOE) (/kWh), and Net Present Cost (NPC) (M) were calculated for one hybrid configuration, SPV-DPG-BS-GS, and two standalone configurations, DPG and SPV-BS. Configurations with SPV integrated had lower LCOEs than DPGs in both EAAs. In Southern Nigeria, solar PV combinations with battery storage provided the highest performance for a hybrid power system. In the medical contexts, a hybrid power system achieves higher overall performance

    A comparison of the physical and chemical differences between cancellous and cortical bovine bone mineral at two ages

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    To assess possible differences between the mineral phases of cortical and cancellous bone, the structure and composition of isolated bovine mineral crystals from young (1–3 months) and old (4–5 years) postnatal bovine animals were analyzed by a variety of complementary techniques: chemical analyses, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and 31P solid-state magic angle spinning nuclear magnetic resonance spectroscopy (NMR). This combination of methods represents the most complete physicochemical characterization of cancellous and cortical bone mineral completed thus far. Spectra obtained from XRD, FTIR, and 31P NMR all confirmed that the mineral was calcium phosphate in the form of carbonated apatite; however, a crystal maturation process was evident between the young and old and between cancellous and cortical mineral crystals. Two-way analyses of variance showed larger increases of crystal size and Ca/P ratio for the cortical vs. cancellous bone of 1–3 month than the 4–5 year animals. The Ca/(P + CO3) remained nearly constant within a given bone type and in both bone types at 4–5 years. The carbonate and phosphate FTIR band ratios revealed a decrease of labile ions with age and in cortical, relative to cancellous, bone. Overall, the same aging or maturation trends were observed for young vs. old and cancellous vs. cortical. Based on the larger proportion of newly formed bone in cancellous bone relative to cortical bone, the major differences between the cancellous and cortical mineral crystals must be ascribed to differences in average age of the crystals
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