Aramid Fiber Reinforced Polymer (AFRP) composites provide a companionable and beneficial technique to strengthen structures and noticeable advantages in terms of fire and heat resistance and vapor ...permeability. AFRP also improves the corrosion resistivity of the structural members, and it delays the buckling. These characteristics of AFRP materials have been catching attention of the technical community to study the mechanical behavior to define comprehensive strengthening design guidelines. This research work studied the effect of AFRP on a steel beam with five types of strengthening and without strengthening pattern. Several tests were carried out to find the compressive and flexural behavior of structure considering with strengthening and without strengthening. From the experimental result, it can be concluded that the load carrying capacity and stiffness of structure considerably enhanced due to external bonding of normal modulus AFRP. The wrapping of AFRP effectively delayed the local buckling and punching for the compressive and flexural loading, respectively. Then, the beam was modeled by using ANSYS 16.0 to authenticate the experimental results and the numerical results such as deflection and maximum load carrying capacity for the different patterns of strengthening quite agreed with the experimental results. Finally, this study concluded with showing different experimental failure modes and comparison made with the numerical results. It is expected that the outcome of this research will be of significant help for the strengthening of the structure.
An efficient way through borohydride synthesis route using NaBH4 was performed to prepare pure zirconia nanopowders via three different conditions such as gelation, precipitation, and constant pH. ...Zirconia powders prepared through constant pH route show highest activation energy of crystallization (Ea = 260 kJ/mol) or higher exothermic peak temperature (717°C), when compared with gelation or precipitation route due to its controlled growth of smaller crystallites. The released huge amount of H2 gas bubbles during borohydride synthesis via constant pH route play a major role for formation of loose smaller crystallites and thus enhances the activation energy of crystallization of pure zirconia. So, the as‐prepared zirconia powders prepared through constant pH route remain amorphous up to 600°C and pure t‐ZrO2 (~20 nm) was stable up to 800°C.
Abstract
Selection of gastropod shells as shelter by hermit crabs in controlled experiments would provide useful information on the utility of these shells in nature. In this study, shell size and ...species preferences of Diogenes alias from the northeastern Arabian Sea were quantified by free choice experiments. Males of D. alias, prefer Indothais lacera and Tibia curta, when choice was given; no differences were found for other demographic groups. All hermit crabs occupied larger shells than the shells they occupied in nature. The best correlation was observed between internal volume, weight, and aperture width of the shell with the size of the hermit crab. This pattern has also been reported for other species (i.e., Clibanarius albidigitus, Calcinus tibicen, and C. obscurus). Furthermore, the present study highlights the importance of optimal resources in a scarce environment.
The COVID-19 pandemic has caused increased anxiety among medical students due to the uncertainty of the long-term effects on the future of medical education. There are currently insufficient studies ...aimed at investigating the changes in the mental health and studying habits of medical students during public health emergencies such as this pandemic, as well as methods that can be incorporated to appropriately manage anxiety effectively. To investigate the psychological impact and associated factors on medical students during the pandemic. This retrospective, cross-sectional study consisted of 291 medical students of the faculty of medical sciences at the university of the West Indies, St. Augustine campus, Trinidad and Tobago. The mental health and study habits of said students were assessed with the use of questionnaires via an online survey platform. Data of our study showed that 56% of the students were experiencing increased stress and anxiety. Students of 82.8% experienced irregular sleeping habits and 76.3% of participants experienced a change in eating habits brought on by the pandemic. Participants of 67.4% studied less than 4 hrs. a day, 61.5% were less productive, 62.2% showed an inability to focus and avoid distractions in their study environment during the COVID-19 pandemic. There is a need for proper supportive strategies to assist students in effectively managing anxiety and depression during public health emergencies such as COVID-19. It is suggested that all universities, colleges and education bodies alike implement a pandemic preparedness course as well as an accessible online support forum.
We report on the effect of low substrate temperature on the correlation between structure, magnetic properties, and micromagnetic behavior of Fe 70 Ga 30 thin films. The enhanced grain size and the ...decrease in the number of pinning centers are in correlation with the enhanced saturation magnetization and domain size (~0.2-<inline-formula> <tex-math notation="LaTeX">0.5~\mu \text{m} </tex-math></inline-formula>), respectively. Estimated effective magnetic anisotropy energy (<inline-formula> <tex-math notation="LaTeX">K_{\mathrm {eff}} </tex-math></inline-formula>) is found to increase with substrate temperature from <inline-formula> <tex-math notation="LaTeX">7.5 \times 10^{5} </tex-math></inline-formula> J/m 3 (room temperature) to <inline-formula> <tex-math notation="LaTeX">13.6 \times 10^{5} </tex-math></inline-formula> J/m 3 (350 °C). The coercivity variation from the object-oriented micromagnetic framework (OOMMF) simulation is in line with respect to experimental values. Spin structure from simulation also indicates multiple-domain configuration when there is a magnetization reversal.
Summary
Novel direct‐acting antivirals (DAAs) are now the standard of care for the management of hepatitis C virus (HCV) infection. Branded DAAs are associated with high sustained virological ...response at 12 weeks post‐completion of therapy (SVR12), but are costly. We aimed to assess the efficacy of generic oral DAAs in a real‐life clinical scenario. Consecutive patients with known HCV infection who were treated with generic‐oral DAA regimens (May 2015 to January 2017) were included. Demographic details, prior therapy and SVR12 were documented. Four hundred and ninety patients (mean age: 38.9 ± 12.7 years) were treated with generic DAAs in the study time period. Their clinical presentations included chronic hepatitis (CHC) in 339 (69.2%) of cases, compensated cirrhosis in 120 (24.48%) cases and decompensated cirrhosis in 31 (6.32%) cases. Genotype 3 was most common (n = 372, 75.9%) followed by genotype 1 (n = 97, 19.8%). Treatment naïve and treatment‐experienced (defined as having previous treatment with peginterferon and ribavirin) were 432 (88.2%) and 58 (11.8%), respectively. Generic DAA treatment regimens included sofosbuvir in combination with ribavirin (n = 175), daclatasvir alone (n = 149), ribavirin and peginterferon (n = 80), ledipasvir alone (n = 43), daclatasvir and ribavirin (n = 37), and ledipasvir and ribavirin (n = 6). Overall SVR12 was 95.9% (470/490) for all treatment regimens. SVR12 for treatment naïve and experienced patients was 97.0% (419/432) and 87.9% (51/58), respectively, P = .005. High SVR12 was observed with various regimens, irrespective of genotype and underlying liver disease status. There were no differences in SVR12 with 12 or 24 weeks therapy. No major adverse event occurred requiring treatment stoppage. Generic oral DAAs are associated with high SVR rates in patients with HCV infection in a real‐life clinical scenario.
The work reported in this paper is focused on the performance of a thermoacoustic refrigerator under various operating conditions. The experiments were conducted with various stack geometries ...fabricated with epoxy glass and Mylar material. Four stacks with different pore sizes are used to evaluate the performance of the refrigerator. Stack 1 has parallel plates of Mylar material 0.12 mm thick spaced 0.36 mm apart. Stacks 2, 3 and 4 are made of epoxy glass with pores of circular cross-section having 1, 2 and 3 mm diameter, respectively. The entire resonator system was constructed from aluminium material coated with polyurethane material from inside to reduce conduction heat losses. Helium gas was used as a working fluid. The experiments were conducted with different drive ratios ranging from 1.6% to 2% with varying cooling load from 2 to 10 W. For the experiments, operating frequencies from 200 to 600 Hz with mean pressure varying from 2 to 10 bar in steps of 2 bar each were considered. The temperatures of the hot end and cold end of the heat exchangers were recorded using RTDs and a data acquisition system under various operating conditions. The coefficient of performance (COP) and relative COP (COPR) are evaluated. Results show that COP of the refrigerator rises with increase of cooling load and decreases at higher drive ratio. It was also observed that the temperature difference between the hot end and cold end of the stack is higher at 2 W cooling load for 400 Hz operating frequency. The temperature difference between the hot end and cold end of the stack was observed to be 19.4, 17.2, 14 and 12.4°C for stacks 1, 2, 3 and 4, respectively, for 10 bar mean pressure and 2 W cooling load. The temperature difference and COP of the parallel plate stack are better compared with other stack geometries.
Diabetic neuropathy is a disorder that affects various regions of the nervous system and there is no specific treatment available for it. This study evaluated the protective effect of molsidomine in ...diabetic neuropathy in rats. Diabetes was induced in male Wistar rats by administrating streptozotocin (52 mg/kg ip). Diabetic rats were treated with molsidomine 5 mg/kg po and 10 mg/kg po. After 8 weeks of treatment, motor coordination, mechanical allodynia, mechanical hyperalgesia, nerve conduction velocity, and glycosylated hemoglobin were assessed. Thereafter, animals were killed and the sciatic nerve was isolated for measurement of reduced glutathione and lipid peroxidation, and histopathological analysis. Treatment with molsidomine significantly improved motor coordination, paw withdrawal threshold, mechanical threshold, and nerve conduction velocity. Furthermore, molsidomine treatment also reduced malondialdehyde levels and prevented depletion of reduced glutathione in the sciatic nerve homogenate. Histopathology revealed that molsidomine treatment maintained normal architecture of the sciatic nerve. The results of our study strengthen the alternative use of molsidomine in diabetic neuropathy.
The Ganges Dolphin needs uninterrupted water sources in order to both communicate and to locate its food. Ever-increasing activities in the rivers, especially from motorized vessels, are likely to ...add noise to the soundscape used by this animal and may affect its ability to locate its prey or to sense its environment. Although efforts have been made to improve the quality and flow of the water passing through the Ganga River system, a coordinated effort among policymakers, local implementing authorities, researchers, and funding agencies is needed to achieve the desired goal of restoring the habitat of dolphins, stopping their accidental deaths, increasing their number by captive breeding, and reinstating the biodiversity of aquatic organisms that are passively or actively linked to them. While passive restoration plans such as improving water quality, increasing water volume, and habitat reclamation may work well, the developmental needs along the river exert constant pressure on these plans. These plans may not be effective without the strict enforcement of guidelines, an understanding of the requirements of the plans by all the stakeholders, and the awareness of the population living along the rivers. Therefore, conservation efforts, along with ongoing passive restoration processes aimed at improving the dolphin's living ecosystem by providing enough quality water cover and prey, should focus on increasing the population of these animals by propagating them in captivity through biological or biotechnological means, the success of which needs strong scientific research backing. A scientometric analysis of 20 years (2001–2020) on this animal shows that scientific studies are confined to the ecology of the animals and very little is known either of their biology or their genetics. During the study period, India occupied fourth spot in number of publications on river dolphins, with the Indian Institute of Technology as leading institute. Advance biology techniques may allow us to breed the animal in captivity and even clone the animal. However, the research towards this requires creating the necessary basic infrastructure, funding, and policy support, and developing human resources for research and management.
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