Lithium-Ion Supercapacitor Using Vertically-Aligned Carbon Nanotubes From Direct Growth Technique, And Its Electrochemical Characteristics

This paper reports the fabrication of a lithium ion supercapacitor from vertically-aligned carbon nanotubes (VACNTs) directly grown on a conductive substrate (SUS 310S alloy), using alcohol catalytic chemical vapour deposition technique. CNTs direct growth technique on an electrically conducting foil simplifies the electrode assembly, thus reducing the fabrication process, because the foil can directly act as a current collector. With the VACNT direct growth technique, the supercapacitor electrode was easily prepared and assembled with a non-aqueous 1 M LiPF6 electrolyte. Experimental results show that CNTs (multi-walled type structures of good quality) were perpendicularly grown to the substrate. This device demonstrates a specific capacitance of up to 101 F g-1 (at a scan rate of 1 mVs-1), and a high-rate capability, up to a scan rate of 1000 mVs-1. The VACNT electrode electrochemical performance was also measured by galvanostatic charge-discharge and electrochemical impedance spectroscopy. The effect of free standing CNTs direct growth on the current collector makes insulating binder material unnecessary, thus producing better ion accessibilities to its surface. This also contributes to the good and reliable electrochemical supercapacitor performance

Contribution of glia cells specifically astrocytes in the pathology of depression: immunohistochemical study in different brain areas

Background: The contribution of glial cells to the pathophysiology of depression is an emerging research purpose. This study investigated the deficits in glial cells, specifically astrocytes in various brain regions, after the development of depression and then after voluntary running in depressed rats. Materials and methods: Forty-five adult male Wistar rats aged 8–10 weeks were used in the study. A depression model was generated through a forced swimming programme; voluntary running was allowed on rat running wheels; and brain sections were taken from the hippocampus, dentate gyrus (DG), medial prefrontal cortex (mPFC) and cerebellar cortex. After immunostaining with specific antibodies immuno-stain, the astrocytes, oligodendroglia and microglial cells were counted, and certain indices relating astrocytes to other glial cells were calculated. Astrocytic morphology was studied, and the optical density (OD) of glial fibrillary acidic protein (GFAP) immuno-expression was measured in different groups. Results: Compared to the control group, animals in the depression group exhibited significant decreases in the mean astrocyte count in all studied brain areas, significant decreases in GFAP OD values in all areas and significantly reduced values for all glial astrocyte indices in the hippocampus, DG and mPFC. Compared to the rats in the depression group, those in the depression/exercise group exhibited significantly elevated mean astrocyte and oligodendroglia counts in all studied areas, significantly elevated GFAP OD values in all studied areas, and non-significant differences in glial astrocyte indices in the hippocampus, mPFC and cerebellar cortex. Conclusion: Astrocytes, rather than other glia, constitute a basis for the development and/or relief of depression

Male Partners Involvement in Spousal Contraceptive Use: A Perspective of a Contemporary African Setting

Background: Contraceptive use by women is one of the tools used for promoting family health and slowing population growth. Evidence has suggested that contraceptive use in Nigeria is below acceptable levels in spite of the fact that family planning services are readily available, accessible and affordable. The involvement and participation of males in spousal contraceptive use is seen as the driver to achieving better reproductive outcomes. Hence, this study aimed to determine the level of male involvement in spousal contraceptive use so as to provide evidence based and people oriented information on the available male partner support system for contraceptive use and factors influence it.Methodology: This was a cross sectional study conducted among 80 male partners between April and May, 2017 using quantitative method of data collection and SPSS version 20 was used for data analysis.nbsp Crude and adjusted odds ratios as well asnbsp 95% confidence interval were used in this study with a p-value of le 0.05 considered statistically significant.Results: The mean age of the respondents in the study was 40.0 plusmn 10 years with only 13 (16.3%) of the respondents adjudged as being involved in their spousal contraceptive use. Currently use of male contraceptive method was found to significantly influence involvement in spousal contraceptive use (AOR = 7.1 95% CI = 2.1092 ndash 10.5818 P = 0.015). Conclusion: This study has demonstrated a low level of male involvement in spousal contraceptive use hence, relevant male educational intervention on contraception is required

Prevalence of Muscle Dysmorphia and Associated Health Activities in Male Medical Students in Karachi, Pakistan

Background: Muscle Dysmorphia (MD) is a subtype of body dysmorphic disorder (BDD) and is currently classified under anxiety disorders (subheading: Obsessive-compulsive disorder) in DSM 5. MD is hypothesized to affect the self-esteem and social outlook of the younger generation. MD shows a higher rate in males and may influence their self-confidence rendering them more prone towards using steroids, supplementary proteins and other drugs to alter their physical outlooks as shown in previous studies. This problem has been on the rise lately due to revolutionary advancement in the media and film industry and the abrupt changes about the standards of physical good looks and body shapes. With the lack of studies done in our population, our study will be helpful to consider the prevalence of the disease in our setting and increase awareness in the general public and clinicians. We hope to help clinicians/ therapists find better options in managing the disease. Materials: We performed a cross-sectional study with a sample size of 246 medical school students in Karachi to collect data through self-administered questionnaires. We used the DSM 5 criteria for the diagnosis of BDD and additional questions on the presence of MD. Nutritional habits, exercise routines, use of supplements and drugs were also obtained for exploratory analysis. Results: Our study predicted the prevalence of MD to be 25%. Other main findings included statistical significant associations between MD and the thoughts and practice of steroid use for muscularity. Conclusion: MD is an underdiagnosed and often unrecognized disease that we believe has significant consequences for the young male population. Further work is needed on this in our part of the world. Our research, we believe, can be a stepping stone for further studies that would incorporate wider populations

The elastic properties of unidirectional bamboo fibre reinforced epoxy composites

Natural fibres such as kenaf, jute, bamboo, flax and wood have been the subject of intensive researches in the area of fibre reinforced composite due to their environmental advantages of being renewable, biodegradable and sustainable. Bamboo fibre can be a good choice of natural fibre reinforcement for structural applications due to its excellent strength to weight ratio that is comparable to that of mild steel. In this study, mechanical properties of both continuous and short bamboo fibre reinforced composites are predicted using micromechanical approaches. The finite element method was used where three-dimensional micromechanical representative volume element with square and hexagonal packing geometry was implemented. The results were then compared with the findings from analytical approach that includes the rule of mixture and the Halpin-Tsai model. It was found that for all properties, the FEM and analytical methods give comparable trends of property on volume fraction plots. Furthermore, the longitudinal modulus given by all models are in excellent agreement as it increases linearly with the increase in bamboo fibre volume fraction

Observation of reduced thermal conductivity in a metal-organic framework due to the presence of adsorbates

Whether the presence of adsorbates increases or decreases thermal conductivity in metal-organic frameworks (MOFs) has been an open question. Here we report observations of thermal transport in the metal-organic framework HKUST-1 in the presence of various liquid adsorbates: water, methanol, and ethanol. Experimental thermoreflectance measurements were performed on single crystals and thin films, and theoretical predictions were made using molecular dynamics simulations. We find that the thermal conductivity of HKUST-1 decreases by 40 – 80% depending on the adsorbate, a result that cannot be explained by effective medium approximations. Our findings demonstrate that adsorbates introduce additional phonon scattering in HKUST-1, which particularly shortens the lifetimes of low-frequency phonon modes. As a result, the system thermal conductivity is lowered to a greater extent than the increase expected by the creation of additional heat transfer channels. Finally, we show that thermal diffusivity is even more greatly reduced than thermal conductivity by adsorption

Covariant and Heavy Quark Symmetric Quark Models

There exist relativistic quark models (potential or MIT-bag) which satisfy the heavy quark symmetry (HQS) relations among meson decay constants and form factors. Covariant construction of the momentum eigenstates, developed here, can correct for spurious center-of-mass motion contributions.Proton form factor and M1 transitions in quarkonia are calculated. Explicit expression for the Isgur-Wise function is found and model determined deviations from HQS are studied. All results depend on the model parameters only. No additional ad hoc assumptions are needed.Comment: 34 pages (2 figures not included but avaliable upon request), LATEX, (to be published in Phys.Rev.D

Three-dimensional CFD simulations with large displacement of the geometries using a connectivity-change moving mesh approach

This paper deals with three-dimensional (3D) numerical simulations involving 3D moving geometries with large displacements on unstructured meshes. Such simulations are of great value to industry, but remain very time-consuming. A robust moving mesh algorithm coupling an elasticity-like mesh deformation solution and mesh optimizations was proposed in previous works, which removes the need for global remeshing when performing large displacements. The optimizations, and in particular generalized edge/face swapping, preserve the initial quality of the mesh throughout the simulation. We propose to integrate an Arbitrary Lagrangian Eulerian compressible flow solver into this process to demonstrate its capabilities in a full CFD computation context. This solver relies on a local enforcement of the discrete geometric conservation law to preserve the order of accuracy of the time integration. The displacement of the geometries is either imposed, or driven by fluid–structure interaction (FSI). In the latter case, the six degrees of freedom approach for rigid bodies is considered. Finally, several 3D imposed-motion and FSI examples are given to validate the proposed approach, both in academic and industrial configurations

Thermal performance of cooling strategies for asphalt pavement: a state-of-the-art review

Asphalt pavements absorb and store more heat than natural surfaces. Thus, high temperatures are emitted from conventional asphalt pavements, subsequently releasing heat into the atmosphere and contributing to the urban heat island (UHI) phenomenon. Several cool pavement strategies, including the provision of additives and materials, surface coating and layer design, have been introduced to reduce the impact of UHI. This article provides a detailed review of the thermal properties of these mitigation measures in the context of cool asphalt pavements. The literature can be divided into three segments. The first segment discusses the impact of pavements on UHI and heat transfer mechanisms in pavements. The second segment focuses on various thermo physical properties that play an important role in mitigation measures; these properties include albedo (α), emissivity (ε), solar reflective index, thermal conductivity (k), specific heat capacity (Cp) and thermal diffusivity. The third segment discusses cool asphalt pavement strategies which specifically cover the ability of the pavement to absorb and reflect solar energy on the basis of the materials and treatments used. The literature reveals that cooling strategies that deal with the pavement surface are important due to its direct incident solar effect, which depends on surface colour, material, shape and roughness. By using high-albedo and high-emissivity surfaces, the pavement can store less heat and lower the surface temperature. These results can also be achieved by designing the materials and pavement layers with low thermal conductivity and high specific heat capacity to reduce thermal diffusivity and pavement temperature and thus combat the heat radiated by the asphalt pavement