Interfacial control of donor and acceptor molecular conformations in bulk heterojunction active layers for improved power conversion efficiency in organic solar cells

Organic photovoltaics is currently considered a promising source of low-cost, high-performance, and flexible emerging renewable energy technology. With the ongoing research and development efforts, it holds the potential for future commercial applications. However, to improve photovoltaic performances, one of the significant aspects is to control the thin film molecular morphology. Among several strategies such as complex donor, acceptors synthesis, thin film processing, heat treatments for regulating the bulk heterojunction molecular conformations, interface controlled active layer crystal orientation, growth and its impact on the photovoltaics performance hasn’t been addressed mostly. Enhanced chemical interaction between the electron transport layer and the active layer can greatly regulate the crystal conformations of the donor acceptors active layer. Here in this thesis, we investigated non-fullerene-based donor acceptors BHJ active layer crystal confirmations regulation with novel electron transport layers and its impact on the improvement of device performance. We utilized different donor acceptors systems (PTB7-Th: IEICO-4F, PTB7-Th: ITIC-4F, PM6: Y6) with chemically modified electron transport layers, where different advanced analytical techniques such as synchrotron-based wide-angle X-ray scattering techniques, near edge X-ray absorption fine structure, X-ray photoemission spectroscopy, Time of flight- secondary ion mass spectrometry were used to understand the interaction between the layers. We showed the in-depth correlation between the interface-controlled molecular morphology and the device performance. The overall insights achieved during this work are highly significant in organic photovoltaic technology

Design, analysis and control of solar heating system with seasonal thermal energy storage

The majority of the electricity consumption in Canadian single-family house is for space heating and water heating. Currently, around 99% house in Canada using the conventional grid electricity for those purposes. To utilize the sun’s free energy for space heating and domestic water heating, first a sessional solar thermal energy storage system (SSTES) has been designed and investigated to determine their thermal and electrical performance of a house consists of four persons in the Canadian climate environment. The detailed mathematical formulation and sizing of each SSTES system component have been developed. Similarly, the components mathematical modelling, sizing of solar collector-based TES system, a hybrid solar Photovoltaic thermal (PV/T) based TES system, a Photovoltaic based TES system has been designed. To validate the feasibility and numerical studies of the developed STES configurations, all configurations have been simulated in a professional thermal simulation software named as PolySun, and only solar collector-based TES system has been designed and simulated at MATLAB/Simulink environment packages. The proposed TES system performance have been compared with the existing conventional system. All configurations have been tested using the solar radiation and other weather data of St. John’s city/NL city in Canada. The main objective to design a suitable TES system for space heating and water heating so that the residence can save high monthly electricity bill. For experimental validation, an open source IoT platform named openHAB smart home automation is used as a home server, an ESP32 Thing microcontroller board has been used as Microcontroller unit where all sensors and output devices (relays, thermostat settings channels) are connected for data acquisition and control. The proposed setup is able to monitor the TES system parameters, and able to control locally/remotely and manually/automatically. The proposed system is the low cost, low power consumption prototype which will be a commercial solution of TES system monitoring and remote control

Coordinated Control of Interconnected Microgrid and Energy Storage System

Several microgrids can be interconnected together to enhance the grid reliability and reduce the cost of supplying power to an island area where conventional power grid cannot be connected. Source and load demand do not properly balance always. Besides that, sometimes power and frequency fluctuation has occurred in MG at island mode. Need to design a special control for maintaining the state of charge (SoC) of energy storage system. This paper proposes a new power supply system for an island area that interconnects two microgrids with a single energy storage system (ESS). An algorithm has been proposed that control the microgrids energy storage system for spinning reserve and load power/frequency regulation purpose. The minimum loading constraints of diesel engine generator (DEG) is considered and the SOC of the ESS is properly maintained

Load analysis of RUET, ECE building and design of a rooftop PV system to meet all its energy needs

In this research, Rajshahi University of Engineering & Technology (RUET), Electrical and Computer Engineering (ECE) building load is used to design an isolated PV system. Building yearly electrical load data and available roof area was collected. The system sizing is done using Homer Pro. The designed system consists of complete photovoltaic mini-grid systems. The total installment cost, operating and maintenance cost, and the complete system design and analysis are presented in the paper. The designed system dynamic simulations using Simulink are also included in the paper. A detailed analysis shows that the designed system can provide all the electrical needs of that ECE university building

Econometric Analysis of Production Behavior in the Chemical Industry of Bangladesh: A Panel Data Framework

In this study we have attempted to consider the relationship between the gross output and few explanatory variables in the form of Cobb-Douglas production function model of different firms of Chemical industry of Bangladesh using panel data framework. For analysis purpose we have used data for 4 sub-sectors of chemical industry namely, PVC pipe, Paper, Sanitary ware and Insulator for the period 1999 to 2009.However, for our study purpose we have considered only fixed effect model version of panel data. In this study we consider only four possible cases of fixed effect model which are (1) all coefficients constant across time and individuals, (2) slope coefficients constant over individuals and time but intercept varies across individuals, (3) slope coefficients constant over individuals and time but intercept varies over individuals and time, (4) all coefficients varies across individuals. To stay in the competitive market we have to invest as much possible. Total cost has positive effect on the production. We have considered economies of scale. Results indicate the necessity for appropriate policies at the national level for raising production to increase contribution of chemical industry to GDP

Outcome of classical and reversal stapedotomy in otosclerosis

Classical and reversal stapedotomy both are exclusively done in otosclerosis but definite information regarding surgical advances, postoperative results, complications and information about how and in which patients these surgical techniques should exclusively be used are a source of continuous discussions. This prospective observational study was conducted in the Department of Otolaryngology-Head & Neck Surgery, Bangabandhu Sheikh Mujib Medical University, Shahbagh, Dhaka from July 2019 to December 2020 o compare the outcomes of classical and reversal stapedotomy in patients with otosclerosis. Total 28 cases of otosclerosis who underwent stapedotomy were divided in to two groups i.e. Group A (classical stapedotomy) & Group B (reversal stapedotomy) with 14 patients in each group. All patients were followed up post-operatively up to 3 months with Pure-tone audiometry (PTA). There is no significant difference between classical and reversal stapedotomy approach in terms of hearing improvement and complications. Chorda tympani injury was the main complication in both the groups. Regarding hearing gain and complications there was no significant difference between classical and reversal stapedotomy approach. BSMMU J 2022; 15(2): 121-12

MyD88 TIR domain higher-order assembly interactions revealed by microcrystal electron diffraction and serial femtosecond crystallography.

MyD88 and MAL are Toll-like receptor (TLR) adaptors that signal to induce pro-inflammatory cytokine production. We previously observed that the TIR domain of MAL (MALTIR) forms filaments in vitro and induces formation of crystalline higher-order assemblies of the MyD88 TIR domain (MyD88TIR). These crystals are too small for conventional X-ray crystallography, but are ideally suited to structure determination by microcrystal electron diffraction (MicroED) and serial femtosecond crystallography (SFX). Here, we present MicroED and SFX structures of the MyD88TIR assembly, which reveal a two-stranded higher-order assembly arrangement of TIR domains analogous to that seen previously for MALTIR. We demonstrate via mutagenesis that the MyD88TIR assembly interfaces are critical for TLR4 signaling in vivo, and we show that MAL promotes unidirectional assembly of MyD88TIR. Collectively, our studies provide structural and mechanistic insight into TLR signal transduction and allow a direct comparison of the MicroED and SFX techniques

MyD88 TIR domain higher-order assembly interactions revealed by microcrystal electron diffraction and serial femtosecond crystallography.

MyD88 and MAL are Toll-like receptor (TLR) adaptors that signal to induce pro-inflammatory cytokine production. We previously observed that the TIR domain of MAL (MALTIR) forms filaments in vitro and induces formation of crystalline higher-order assemblies of the MyD88 TIR domain (MyD88TIR). These crystals are too small for conventional X-ray crystallography, but are ideally suited to structure determination by microcrystal electron diffraction (MicroED) and serial femtosecond crystallography (SFX). Here, we present MicroED and SFX structures of the MyD88TIR assembly, which reveal a two-stranded higher-order assembly arrangement of TIR domains analogous to that seen previously for MALTIR. We demonstrate via mutagenesis that the MyD88TIR assembly interfaces are critical for TLR4 signaling in vivo, and we show that MAL promotes unidirectional assembly of MyD88TIR. Collectively, our studies provide structural and mechanistic insight into TLR signal transduction and allow a direct comparison of the MicroED and SFX techniques

A Comparison of Solar Photovoltaic and Solar Thermal Collector for Residential Water Heating and Space Heating System

Almost all single-family detached houses in Canada consume enormous electrical energy for space heating and domestic hot water (DHW) purposes. There are many possibilities to design an energy-efficient house. A solar water heating system can be used for domestic water and space heating. Water temperature can be kept constant always by connecting a heat pump or oil burner to the main tank because solar energy is intermittent. The sizing of solar photovoltaic and collector, tank, heat pump is essential to design an effective system based on the system energy consumption. The existing house is just a conventional house where space and water heating are provided by the grid electricity only. In this research, two possible ways of thermal energy storage systems have been designed for a residential single-family house with solar collector and solar photovoltaic. It is proved that the proposed PV based energy storage system is highly suitable considering lower cost, high output power, flexibility, and easy installation