Low-Velocity Impact, Vibration and Shock Response of Unstitched/Stitched E- And S- Glass/Vinyl Ester Composites

In this study, the effects of through-thickness stitching on the dynamic properties, low-velocity impact and shock responses of stitched and unstitched E- and S- Glass/Vinyl Ester composites have been investigated. The stiffness and loss factor (inherent damping) properties are obtained from impulse-frequency response experiments using the hammer excitation method. Drop weight impact testing machine was used to carry out low-velocity punch shear tests on the composite specimens following ASTM D3763 Standard, and shock tube apparatus was used to determine center point deflection under blast loading. The stitching increased the dynamic flexural modulus by 13% for E- and 8% for S- Glass/Vinyl Ester composites but had minimal change in the case of loss factor. The stitching also demonstrated approximately 20% increase in total energy absorption and approximately 40% increase in fracture energy for E- Glass/Vinyl Ester while showing approximately 12% increase in total energy absorption and approximately 30% increase in fracture energy for S- Glass/Vinyl Ester. Under shock loading, the stitched E- Glass/Vinyl Ester specimens exhibited lowest center point deflection of 3.7 mm center point displacement, indicating greater resistance while the rest had values within the range of 4 mm to 4.5 mm. The average energy absorption up to the point of maximum deflection was higher for the unstitched specimens compared to their stitched counterparts

Overlapped-MIMO Radar Waveform Design for Coexistence With Communication Systems

This paper explores an overlapped-multiple-input multiple-output (MIMO) antenna architecture and a spectrum sharing algorithm via null space projection (NSP) for radar-communications coexistence. In the overlapped-MIMO architecture, the transmit array of a collocated MIMO radar is partitioned into a number of subarrays that are allowed to overlap. Each of the antenna elements in these subarrays have signals orthogonal to each other and to the elements of the other subarrays. The proposed architecture not only improves sidelobe suppression to reduce interference to communications system, but also enjoys the advantages of MIMO radar without sacrificing the main desirable characteristics. The radar-centric spectrum sharing algorithm then projects the radar signal onto the null space of the communications system's interference channel, which helps to avoid interference from the radar. Numerical results are presented which show the performance of the proposed waveform design algorithm in terms of overall beampattern and sidelobe levels of the radar waveform and finally shows a comparison of the proposed system with existing collocated MIMO radar architectures.Comment: accepted at IEEE WCN

Off-grid electrification with solar home systems: An appraisal of the quality of components

Solar home systems (SHS) are seen as an attractive option for off-grid electrification in rural areas in developing countries. The combined effect of declining photovoltaic module costs and success in micro-finance has resulted in increased SHS installations in emerging economies in Asia such as Bangladesh. Majority of the SHS components are now manufactured locally with the exception of PV cells. Considering the role of component quality in SHS performance, technical quality of four key SHS components: solar panel, battery, charge controller and lamp circuit (inverter) from market-leading manufacturers were evaluated in this study in laboratory settings, against national and international standards. All of the tested components met some evaluation criteria in their respective categories but none met all. Key performance failures were found to be related to inverter efficiency, reverse polarity protection in charge controllers and battery capacity, which are critical for optimum performance of the system. Findings in this study point towards an ineffective regulatory mechanism for quality assurance and the protection of consumer rights, which needs to be rectified for maintaining public confidence and sustaining the growth of SHS based off-grid electrification

Enhancing the Stretchability of Two-Dimensional Materials through Kirigami: A Molecular Dynamics Study on Tungsten Disulfide

In recent years, the 'kirigami' technique has gained significant attention for creating meta-structures and meta-materials with exceptional characteristics, such as unprecedented stretchability. These properties, not typically inherent in the original materials or structures, present new opportunities for applications in stretchable electronics and photovoltaics. However, despite its scientific and practical significance, the application of kirigami patterning on a monolayer of tungsten disulfide (WS2), a van der Waals material with exceptional mechanical, electronic, and optical properties, has remained unexplored. This study utilizes molecular dynamics (MD) simulations to investigate the mechanical properties of monolayer WS2 with rectangular kirigami cuts. We find that, under tensile loading, the WS2 based kirigami structure exhibits a notable increase in tensile strain and a decrease in strength, thus demonstrating the effectiveness of the kirigami cutting technique in enhancing the stretchability of monolayer WS2. Additionally, increasing the overlap ratio enhances the stretchability of the structure, allowing for tailored high strength or high strain requirements. Furthermore, our observations reveal that increasing the density of cuts and reducing the length-to-width ratio of the kirigami nanosheet further improve the fracture strain, thereby enhancing the overall stretchability of the proposed kirigami patterned structure of WS2.Comment: 19 pages, 5 figure

In-vitro antioxidant activities, anti-nociceptive and neuropharmacological activities of Polygonum hydropiper

In the present study in-vitro antioxidant activities, anti-nociceptive assessment and neuropharmacological study of the leaf extract of Polygonum hydropiper was performed. In-vitro antioxidant activity of the extracts of P. hydropiper was performed using DPPH free radical scavenging, cupric reducing antioxidant capacity, total antioxidant capacity, total phenol and total flavonoid content determination assays; anit-nociceptive activity was done by using acetic acid induced writhing method and neuropharmacological activities were assessed by  open field test and swimming test. The plant’s leaf extracts exhibit potent antioxidant activities; significant anti-nociceptive activity and neuropharmacological activity. Keywords: Polygonum hydropiper, in-vitro antioxidant activities, anti-nociceptive activity, neuropharmacological activities

Puff or pass: do social media and social interactions influence smoking behaviour of university students? A cross-sectional mixed methods study from Dhaka, Bangladesh.

OBJECTIVE: To determine whether the odds of being a smoker differ based on social media use and social interactions among urban university students in Bangladesh. HYPOTHESIS: Social media use and social interactions influence the smoking behaviour of Bangladeshi university students, particularly in starting and maintaining cigarette smoking. DESIGN AND SETTING: A cross-sectional study using mixed methods on 600 student smokers and non-smokers recruited from two public and two private universities in Dhaka, Bangladesh, a lower middle-income country with limited resources. Exclusion criteria were those who did not use any form of social media and PhD students. RESULTS: Odds of smoking were significantly higher for those who socialised more than 4 hours/day (p<0.05; OR 1.75; 95% CI 1.12 to 2.75) and typically at night (p<0.05; OR 2.80; 95% CI 1.95 to 4.00). Odds of smoking were also higher for those who liked (p<0.05; OR 4.85; 95% CI 3.32 to 7.11), shared (p<0.05; OR 20.50; 95% CI 13.02 to 32.26) and followed (p<0.05; OR 2.88; 95% CI 1.36 to 6.11) tobacco-related content on social media. Qualitative analysis resulted in emergent themes of smokers imitating tobacco-related photos or videos seen on social media and peers as an influence for smoking initiation. CONCLUSION: This study suggests social media and social interactions may influence smoking behaviour in university students in Dhaka, Bangladesh. Future research should continue to investigate the roles social media and social interaction have on smoking in order to explore social media-based smoking cessation interventions or dissemination of smoking health hazards through social media

Processed Radio Frequency towards Pancreas Enhancing the Deadly Diabetes Worldwide

Diabetes is a chronic and debilitating disease, which is associated with a range of complications putting tremendous burden on medical, economic and socio-technological infrastructure globally. Yet the higher authorities of health services are facing the excruciating cumulative reasons of diabetes as a very imperative worldwide issue in the 21st century. The study aims to relook at the misapplication of the processed radio frequency that frailties in the pancreas within and around the personal body boundary area. The administered sensor data were obtained at laboratory experiments from the selected specimens on dogs and cats in light and dark environments. The study shows the frequent urine flow speed varies with sudden infection due to treated wireless sensor networks in active open eyes. The overweight and obese persons are increasingly affected in diabetes with comprehensive urinary pressure due to continuous staying at dark environment. The findings replicate the increasing tide of diabetes globally. The study also represents the difficulties of physicians to provide adequate diabetic management according to their expectancy due to insecure personal area network control unit.Dynamic sensor network is indispensable for healthcare but such network is at risk to health security due to digitalized poisoning within GPS positions. The study recommends the anti-radiation integrated system policy with user’s security alternative approach to inspire dealing with National Health Policy and Sustainable Development Goals 2030

IoT-based emergency vehicle services in intelligent transportation system

Emergency Management System (EMS) is an important component of Intelligent transportation systems, and its primary objective is to send Emergency Vehicles (EVs) to the location of a reported incident. However, the increasing traffic in urban areas, especially during peak hours, results in the delayed arrival of EVs in many cases, which ultimately leads to higher fatality rates, increased property damage, and higher road congestion. Existing literature addressed this issue by giving higher priority to EVs while traveling to an incident place by changing traffic signals (e.g., making the signals green) on their travel path. A few works have also attempted to find the best route for an EV using traffic information (e.g., number of vehicles, flow rate, and clearance time) at the beginning of the journey. However, these works did not consider congestion or disruption faced by other non-emergency vehicles adjacent to the EV travel path. The selected travel paths are also static and do not consider changing traffic parameters while EVs are en route. To address these issues, this article proposes an Unmanned Aerial Vehicle (UAV) guided priority-based incident management system to assist EVs in obtaining a better clearance time in intersections and thus achieve a lower response time. The proposed model also considers disruption faced by other surrounding non-emergency vehicles adjacent to the EVs’ travel path and selects an optimal solution by controlling the traffic signal phase time to ensure that EVs can reach the incident place on time while causing minimal disruption to other on-road vehicles. Simulation results indicate that the proposed model achieves an 8% lower response time for EVs while the clearance time surrounding the incident place is improved by 12%