Experimental Evaluation of Flexural Strength and Ductility of One-Way Concrete Slab Panels Reinforced with Welded Wires and Deformed Bars

This study evaluates the flexural strength and ductility of one-way concrete slab panels reinforced with deformed bar and welded wire under the application of pure bending. An experimental database of flexural strength and ductility for a set of three slab panels reinforced with 10 mm deformed bar, three panels with 6 mm welded wire reinforcement (WWR), and three panels with 8 mm WWR has been developed, with each slab panel having a dimension of 762 mm by 2286 mm. The deflection and ductility factors of the specimens are investigated. The results show that the slab panels reinforced with 6 mm WWR exhibit less vertical deflection at fracture in comparison to those with 8 mm WWR. Welded wire reinforced slab panels demonstrated uniformly distributed crack propagation in comparison to deformed bars. In addition, the slab panels with 8 mm WWR exhibit higher flexural strength than the 6 mm WWR reinforced panels. The 10 mm deformed bar-reinforced slab panels exhibited greater deflection at fracture compared to WWR specimens. The reason for the lower ductile behavior of slab panels with 6 mm WWR is due to the fact that 6 mm WWR, produced locally in Bangladesh, is manufactured by the cold-drawn method and has a lower ductility in compliance with BDS ISO 6935 Class A, which does not conform to ASTM A1064. Both 8 mm WWR and 10 mm deformed bars conform to BDS ISO 6935 Class D and ASTM A1064. Hence, the 6 mm WWR with Class A ductility is not recommended for reinforced concrete (RC) slab panels based on the experimental results conducted in this study, whereas the 8 mm WWR and the 10 mm deformed bar with Class D ductility are suitable for structural use as recommended in ACI 318

Application of Computer Vision and Mobile Systems in Education: A Systematic Review

The computer vision industry has experienced a significant surge in growth, resulting in numerous promising breakthroughs in computer intelligence. The present review paper outlines the advantages and potential future implications of utilizing this technology in education. A total of 84 research publications have been thoroughly scrutinized and analyzed. The study revealed that computer vision technology integrated with a mobile application is exceptionally useful in monitoring students’ perceptions and mitigating academic dishonesty. Additionally, it facilitates the digitization of handwritten scripts for plagiarism detection and automates attendance tracking to optimize valuable classroom time. Furthermore, several potential applications of computer vision technology for educational institutions have been proposed to enhance students’ learning processes in various faculties, such as engineering, medical science, and others. Moreover, the technology can also aid in creating a safer campus environment by automatically detecting abnormal activities such as ragging, bullying, and harassment

A 30-day follow-up study on the prevalence of SARS-COV-2 genetic markers in wastewater from the residence of COVID-19 patient and comparison with clinical positivity

Wastewater based epidemiology (WBE) is an important tool to fight against COVID-19 as it provides insights into the health status of the targeted population from a small single house to a large municipality in a cost-effective, rapid, and non-invasive way. The implementation of wastewater based surveillance (WBS) could reduce the burden on the public health system, management of pandemics, help to make informed decisions, and protect public health. In this study, a house with COVID-19 patients was targeted for monitoring the prevalence of SARS-CoV-2 genetic markers in wastewa-ter samples (WS) with clinical specimens (CS) for a period of 30 days. RT-qPCR technique was employed to target non-structural (ORF1ab) and structural-nucleocapsid (N) protein genes of SARS-CoV-2, according to a validated experimental protocol. Physiological, environmental, and biological parameters were also measured following the American Public Health Association (APHA) standard protocols. SARS-CoV-2 viral shedding in wastewater peaked when the highest number of COVID-19 cases were clinically diagnosed. Throughout the study period, 7450 to 23,000 gene copies/1000 mL were detected, where we identified 47 % (57/120) positive samples from WS and 35 % (128/360) from CS. When the COVID-19 patient number was the lowest (2), the highest CT value (39.4; i.e., lowest copy number) was identified from WS. On the other hand, when the COVID-19 patients were the highest (6), the lowest CT value (25.2 i.e., highest copy numbers) was obtained from WS. An advance signal of increased SARS-CoV-2 viral load from the COVID-19 patient was found in WS earlier than in the CS. Using customized primer sets in a traditional PCR approach, we confirmed that all SARS-CoV-2 variants identified in both CS and WS were Delta variants (B.1.617.2). To our knowledge, this is the first follow-up study to determine a temporal relationship be-tween COVID-19 patients and their discharge of SARS-CoV-2 RNA genetic markers in wastewater from a single house including all family members for clinical sampling from a developing country (Bangladesh), where a proper sewage system is lacking. The salient findings of the study indicate that monitoring the genetic markers of the SARS-CoV-2 virus in wastewater could identify COVID-19 cases, which reduces the burden on the public health system during COVID-19 pandemics.Peer reviewe

Wastewater-based epidemiological surveillance to monitor the prevalence of SARS-CoV-2 in developing countries with onsite sanitation facilities

Wastewater-based epidemiology (WBE) has emerged as a valuable approach for forecasting disease outbreaks in developed countries with a centralized sewage infrastructure. On the other hand, due to the absence of well-defined and systematic sewage networks, WBE is challenging to implement in developing countries like Bangladesh where most people live in rural areas. Identification of appropriate locations for rural Hotspot Based Sampling (HBS) and urban Drain Based Sampling (DBS) are critical to enable WBE based monitoring system. We investigated the best sampling locations from both urban and rural areas in Bangladesh after evaluating the sanitation infrastructure for forecasting COVID-19 prevalence. A total of 168 wastewater samples were collected from 14 districts of Bangladesh during each of the two peak pandemic seasons. RT-qPCR commercial kits were used to target ORF1ab and N genes. The presence of SARS-CoV-2 genetic materials was found in 98% (165/168) and 95% (160/168) wastewater samples in the first and second round sampling, respectively. Although wastewater effluents from both the marketplace and isolation center drains were found with the highest amount of genetic materials according to the mixed model, quantifiable SARS-CoV-2 RNAs were also identified in the other four sampling sites. Hence, wastewater samples of the marketplace in rural areas and isolation centers in urban areas can be considered the appropriate sampling sites to detect contagion hotspots. This is the first complete study to detect SARS-CoV-2 genetic components in wastewater samples collected from rural and urban areas for monitoring the COVID-19 pandemic. The results based on the study revealed a correlation between viral copy numbers in wastewater samples and SARS-CoV-2 positive cases reported by the Directorate General of Health Services (DGHS) as part of the national surveillance program for COVID-19 prevention. The findings of this study will help in setting strategies and guidelines for the selection of appropriate sampling sites, which will facilitate in development of comprehensive wastewater-based epidemiological systems for surveillance of rural and urban areas of low-income countries with inadequate sewage infrastructure.This research was supported by Water Aid Bangladesh, North South University, Dhaka, COVID-19 Diagnostic Lab, Department of Microbiology, Noakhali Science and Technology University (NSTU), Noakhali, Bangladesh, the International Training Network of Bangladesh University of Engineering and Technology (ITN-BUET) - Centre for Water Supply and Waste Management, and KTH Royal Institute of Technology, Sweden. We acknowledge the sincere help and support of the staff and volunteers of NSTU-COVID-19 Diagnostic Lab, Noakhali Science and Technology University, Bangladesh during the different phases of the study. PB and MTI acknowledge the Life Science Technology Platform, Science for Life Laboratory for the seed funding to initiate the wastewater-based epidemiological studies for SARS-CoV-2 in Bangladesh. We would also like to acknowledge the two anonymous reviewers for their critical comments as well as their thoughtful insights, which has significantly improved the manuscript.Peer reviewe

A feasibility study of a wi-fi-based vehicular ad hoc network in the Westfield Shopping Mall parking lot using field trial measurements and simulation

Vehicular Ad Hoc Networks (VANETs) play an important role in reducing car accidents on the road as well as in the parking lots of large shopping malls. Providing connectivity as well exchanging warning messages among the vehicles in the parking areas could potentially reduce car accidents. An empirical study using radio propagation measurements to get an insight into the performance of a VANET system in the shopping mall environment is required to assist the efficient design and deployment of such systems. In this thesis, an empirical investigation using field trial measurements (i.e. propagation measurements) to study the performance of an IEEE 802.11n-based VANET in the parking lot of the West City Auckland shopping mall is described and its results are reported. In the investigation, received signal strength, packet send/receipt and response times were measured between two experimental vehicles equipped with 802.11n cards. Received signal strengths were found to have ranged from -45 dBm to -92 dBm in the parking lot. The distance coverage between two experimental vehicles where warning messages were sent successfully were up to 57 m, 17.5 m, 9.4 m, and 68 m at parking levels 1, 2, 3, and the roadside, respectively. Simulations were performed to generalize the measurement results. This thesis also investigates a closest match between the propagation models and measurements. Finally, the thesis provides guidelines for network planners for the deployment of 802.11-based VANET in the parking lot of a large shopping mall

A novel approach to combine the hierarchical and iterative techniques for solving capacitated location-routing problem

This study focuses on the capacitated location-routing problem (CLRP), which is a combination of capacitated facility location problem and capacitated vehicle routing problem. We propose a novel approach to find solutions for CLRP, a common version of location routing problem, founded in the literature. We have proposed an enhanced version of particle swarm optimization (PSO), a swarm inspired metaheuristic to handle CLRP. The proposed approach consists of unique assignment techniques of the customers to the opened depots and a tri-fold PSO based searching strategy which combines the influence of both hierarchical and iterative techniques in order to find near optimal solutions to a CLRP. Two folds of PSO are for maintaining the global view of clustering the nodes and the remaining PSO fold keeps the local nature of prioritizing route construction cost while making a complete solution of CLRP, thus proposed approach preserves the influence of both hierarchical and iterative methods. Experimental performance evaluation of the proposed approach is compared to other particle swarm optimization based methods to solve benchmark instances available in literature which show better performance of the proposed method

Empirical Ratio of Higher Optical Transitions in Semiconducting SWCNTs

In this work, the ‘ratio problem’ among higheroptical transition energies (4th, 5th and 6th transitions) ofsemiconducting single-wall carbon nanotube is discussed. Anumber of semiconducting single-wall carbon nanotubes having(n – m) familyrange 2 to 32 with mod (n-m, 3) ≠0 and havingdiameter range 1.48nm to 3.44nm are considered. Higher opticaltransition energies of all those tubes are recorded from variousexperimental reports based on fluorescence and Ramanspectroscopy. Based on that observation, ratio betweenconsecutive higher transition energies for all semiconducting tubeis expressed empirically through some empirical expressions interms of diameter, (n- m) family and mod value. The empiricalratio matched very well with experiment ratio over the fulldiameter range. The proposed empirical way to expressing thisratio may greatly help in finding the proper ratio of higheroptical transitions without depending on experimental values ofthese transitions.The generated pattern from the plot of thisempirical ratio can also help in Photoluminescence basedchirality assignment

Starting up and operating an apparel brand in Bangladesh

The study was on the ready-to-wear clothing industry in Bangladesh in order to deter-mine what kinds of commercial opportunities are available to business people who want to launch a new company and satisfy the requirements of all of their target customers at the same time. As a direct consequence of the epidemic, many people suffered huge financial losses in their businesses. Some of these individuals are still exerting a great deal of effort in order to make up for the money that they have lost. In light of the recent adjustments, a new firm that opens in the ready-made garment sector of Bangladesh's economy may have problems effectively competing if the required processes are not followed. In the process of composing this thesis, a qualitative method is used. The findings obtained from the qualitative interviews conducted for the thesis demonstrated that Bangladesh is a market that offers lucrative potential for the creation of a clothing brand. There is a potential that new business owners who start their compa-nies during or after the epidemic may be liable to harsh repercussions. This is a possi-bility since there is a possibility. The new company has set as one of its long-term goals the accomplishment of firmly establishing itself as a prominent participant in the world of corporations

Deploying a Low-Cost Wi-Fi-Based Vehicular Ad Hoc Network in a Shopping Mall Parking Lot: An Empirical Study

Vehicular ad hoc networks (VANETs) have the potential to reduce car accidents by facilitating connectivity and warning message exchange between vehicles, both on roads and in parking lots. This research endeavored to accomplish three primary goals: conducting a field measurement in the parking lot of a large shopping mall in Auckland, developing an OPNET-based simulation model to analyze and validate the system performance, and analyzing the compatibility between five selected radio propagation models (Free-space, Shadowing Path-loss, Egli, Hata, and COST231). These models were selected based on their popularity and relevance to our study. We found that the “Free Space” model outperforms in the scenario in which measurements were conducted from the Level-1 car park to the Roadside. The received signal strengths in the parking lot ranged from −45 dBm to −92 dBm. This research also examines the coverage distance for the successful transmission of warning messages, achieving up to 57 m, 17.5 m, 9.4 m, and 68 m at parking levels 1, 2, 3, and the roadside, respectively. Research findings reveal that a low-cost Wi-Fi-based VANET system can be utilized to prevent car accidents in parking lots. Finally, we provide guidelines for network planners to deploy Wi-Fi-based VANET systems in parking lots

Comprehensive Performance Analysis of Zigbee Communication: An Experimental Approach with XBee S2C Module

The recent development of wireless communications has prompted many diversified applications in both industrial and medical sectors. Zigbee is a short-range wireless communication standard that is based on IEEE 802.15.4 and is vastly used in both indoor and outdoor applications. Its performance depends on networking parameters, such as baud rates, transmission power, data encryption, hopping, deployment environment, and transmission distances. For optimized network deployment, an extensive performance analysis is necessary. This would facilitate a clear understanding of the trade-offs of the network performance metrics, such as the packet delivery ratio (PDR), power consumption, network life, link quality, latency, and throughput. This work presents an extensive performance analysis of both the encrypted and unencrypted Zigbee with the stated metrics in a real-world testbed, deployed in both indoor and outdoor scenarios. The major contributions of this work include (i) evaluating the most optimized transmission power level of Zigbee, considering packet delivery ratio and network lifetime; (ii) formulating an algorithm to find the network lifetime from the measured current consumption of packet transmission; and (iii) identifying and quantizing the trade-offs of the multi-hop communication and data encryption with latency, transmission range, and throughput