On body e-shaped patch antenna for biomedical application

An E-shaped micro strip patch antenna is designed and analyzed in this paper which operates in MICS (402.0-406.0MHz) band. The Performance has been observed on a body of human phantom model as well as in free space with different conducting material for the designed antenna. The height of this antenna is taken 1.5mm from the ground plane. At resonance frequency of 405 MHz the S11 parameter is obtained in free space is -23.26dB for conducting material of aluminum and -17.96dB is measured on human phantom body at 405 MHz of resonance frequency. FR4 is used as substrate material. The Specific Absorption Rate (SAR) is found to be 0.3562 W/kg by placing the antanna on human phantom model. VSWR and directivity has been analyzed also

Assessment of Construction Productivity in the Context of Khulna City of Bangladesh

This paper examines the current state of construction productivity in Khulna, Bangladesh and major factors that influence productivity. A questionnaire survey was distributed to various stakeholders and construction projects in Khulna city. Ten projects in Khulna were selected for productivity assessment and a total of 100 respondents participated for ranking the influencing factors. The data were then used to calculate the productivity and relative important index which enabled the factors to be ranked. Factors influencing construction productivity were analyzed using an RII method. The average productivity of formwork, concrete work, brickwork, and plastering work in the Khulna construction industry is 3.40 sqft/hr, 4.98 cft/hr, 1.82 cft/hr, and 8.16 sqft/hr respectively. Analysis of these factors showed that the top five ranked factors affecting construction productivity are labor supervision, skilled labor, availability of materials, availability of equipments and scheduling of work. Therefore, focus should be targeted on these factors to make the construction firms profitable as well as improving the progress in construction works

Techno-Economic Performance and Sensitivity Analysis of an Off-Grid Renewable Energy-Based Hybrid System: A Case Study of Kuakata, Bangladesh

Hybrid renewable energy sources (HRES) are increasingly being utilized to meet global energy demands, particularly in rural areas that rely on diesel generators and are disconnected from the utility grid, due to their environmental and human health benefits. This study investigates the performance of an off-grid, hybrid PV/diesel generator/battery system for a decentralized power plant in Kuakata, Bangladesh, meeting a load demand of 3000 kWh/day with a 501.61 kW peak load demand. HOMER Pro (hybrid optimization model for electric renewable) software (version 3.11) was used to simulate and optimize system operations utilizing real-time solar radiation and load profile data from that location. This study also includes a sensitivity analysis of the off-grid HRES system under different electrical load demands, project longevity, and derating variables. The results reveal that CO2 emissions have potentially decreased by more than 30% and over 10 tons per year, respectively, when compared to traditional power plants. The optimized system’s net present cost (NPC) was determined to be around USD 5.19 million, with a cost of energy (COE) of USD 0.367 per kWh per unit with a 100% renewable component. Furthermore, the current study’s findings are compared to previous research that has resulted in an economical hybrid renewable energy system with an affordable COE. The hybrid energy system under consideration might also be applicable to other parts of the world with comparable climate conditions