Internal migration and the condition of female construction workers: a study in Chittagong city

Women workers are found in certain activities traditionally falling within the male domain. This is particularly the case for landless women who largely belong to the hardcore poor group. It indicates growing economic pressure and erosion of familial support and traditional beliefs and norms regarding women's outside work. With the Bangladesh economy’s heavy dependence on imports Chittagong has traditionally played a very important role in the trading sectors and industrial centre of the country and also commercial capital of Bangladesh which is going through a massive phase of construction of new structures. The study employed triangulation method as a research strategy. The objective of the study is to know the reasons of internal migrations and conditions of female construction workers of Chittagong city. A good number of rural women are involved at urban construction work in Chittagong city where they faces different harmful condition like as long working hour, less salary, lack of women rights, sexual harassment, food expenditure, low health condition, hard working etc. From this rational discussion this papers examine internal migration and the condition of migrant female construction works in Chittagong city

Displacement and deplorable living conditions of slum dwellers: with special reference to Sylhet city

Environmental displacement has already become extreme in geographically and environmentally vulnerable areas in Bangladesh. Thus, climate induced migration to big cities is getting spontaneous over the last few decades. Increasing numbers of slums represent a major challenge to development. Displaced people living in urban slums are in search of better and secure life. But urban slums located mostly in low lying environmentally hazardous area coupled with inadequate facilities like food, shelter, sanitation, high rates of malnutrition, density of population, communicable diseases, exposure to violence, health care make their life even worse. In other words it refers to informal areas suffering from problems of accessibility, narrow streets, the absence of vacant land and open spaces, very high residential densities, insufficient infrastructure and services. The study is fully based on primary data that followed stratified sampling method with triangulation research design and reviewing some related literatures from past research reports. This paper examines that exploration of living conditions of slum dwellers, it is seen that the sketch of their social life is very different, deplorable, unorganized, poor health status, using different kinds of family planning methods, lack of proper water supply and sanitation, low income group with inadequate education, leading unhealthy environment, to enhanced poverty, under nutrition of Bangladeshi's inhabitants those are engaged in various sectors of economical activities. Their present scenario of social life is very pathetic and miserable because of having been deprived from education, employment and other basic facilities of human life and as a result they are being regarded as a reluctant Dwellers. They are far from touch of modernization, fully separated and alienated from the mainstream of society

Facile fabrication of binary g-C3N4/NH2-MIL-125(Ti) MOF nanocomposite with Z-scheme heterojunction for efficient photocatalytic H2 production and CO2 reduction under visible light

A binary g-C3N4/NH2-MIL-125(Ti) MOF nanocomposite was fabricated through a facile sonochemical-assisted thermal approach for enhanced photocatalytic H2 production and CO2 reduction under visible light. Compared to pure g-C3N4, the g-C3N4/MOF photocatalyst showed enhanced visible light absorption with promoted charge carrier separation which increased the H2 production rate and the CO2 reduction into CH4 and CO. This enhancement was attributed to the successfully constructed Z-scheme heterojunction in addition to the visible-active, large surface area and highly CO2 adsorbable NH2-MIL-125(Ti) MOF. The highest H2 production of 480 µmol g−1 was exhibited over the g-C3N4/NH2-MIL-125(Ti) nanocomposite with 20 wt% MOF. Similarly, the highest CO production rate of 338 µmol g−1 was achieved with 20 wt% MOF composite. However, for the CH4 product gas, it was observed that the highest production rate was attained with pure g-C3N4 which reveals the NH2-MIL-125(Ti) MOF selectivity towards CO production instead of CH4. Among all the investigated sacrificial agents for H2 production, methanol was the best. The performance of CO2 reduction process was found to be increasing with the pressure increase. Furthermore, the stability investigations revealed continuous productions of H2, CO and CH4 over the C3N4/MOF photocatalyst in multiple cyclic runs without any significant photocatalyst deactivation. This study provides new ideas for the fabrication of cheap, efficient and easy-synthesized nanomaterials for energy production and environmental remediation applications

Influence of Anodizing Parameters on the Morphological Characteristics of TNTAs

TiO2nanotubes arrays (TNTAs) were synthesized using the anodization method in ethylene glycol (EG)-based electrolyte with different percentages of ammonium fluoride (0.3, 0.4, and 0.5 wt.%) and water content (2.5, 5, and 7.5% vol%). All the samples were ultrasonically cleaned in acetone, ethanol, and deionized water, then dried in air and kept in an etching solution for a while before anodization. The two-step anodization was carried out, followed by thermal treatment at 450°C for the crystallization. The nanotube samples were characterized using FE-SEM analysis. The FE-SEM results showed that the largest tube diameter was 87.74±1.89 nm of the TNTAs prepared in the EG electrolyte with a composition of 7.5% water content and 0.5% ammonium fluoride. The longest tube length analyzed was around 5.3 μm of the TNTAs prepared in the ethylene glycol electrolyte with the composition of 2.5% water content and 0.4% ammonium fluoride percentage, exhibiting a highly ordered, compact honeycomb structure and thick single-walled structure

Latest progress on the influencing factors affecting the formation of TiO2 nanotubes (TNTS) in electrochemical anodization- A minireview

TiO2 nanotubes (TNTs) have drawn special attention for their wide range of applications in a variety of fields. In comparison to other TiO2 nanostructures, it is attracted much due to its high surface area and low fabrication cost. By using the electrochemical anodization approach, highly ordered TNT arrays can be produced with minimum cost compared to other synthesized methods. The nanotubes of the desired diameter, length and wall thickness can be tailored by adjusting anodization parameters. Here in this article, the effects of anodization parameters including type of electrolytes, electrolyte concentration, pH, temperature, aging, anodization voltage, time and type of electrodes on tube formation, tube diameters, length, thickness, organization, and formation mechanisms are reviewed. The collection methods of asproduced TNTs from Ti substrate also summarized in this review. Finally, the article concludes by outlining potential future research scope and challenges

Recent advances on synthesis and photocatalytic applications of MOF-derived carbon materials : A review

Owing to their exceptional advantages, MOF-derived carbon materials (MDCMs) have gained a great interest as promising nanomaterials for environmental and energy photocatalytic applications. Numerous research activities were stimulated accordingly which focused mainly on the properties, synthesis, classifications, structural modulation and applications of their based materials as potential photocatalysts. All these aspects were comprehensively covered and critically discussed in this review in a way that has not been presented previously. Initially, the review outlines the main fundamentals of the photocatalysis process through the utilization of MDCMs. Then, the main properties and characteristics of MDCMs are highlighted. Furthermore, the recent advances in the synthesis approaches and the structural modulation of MDCMs are discussed in depth. Moreover, the main applications of MDCMs including photocatalytic CO2 reduction, H2 production and degradation of pollutants are summarized, considering only the recent studies reported in the past decade. Eventually, the conclusions and future recommendations for the usage of MDCMs in the fields of energy and environmental remediation are presented

A comprehensive review on anodic TiO2 nanotube arrays (TNTAs) and their composite photocatalysts for environmental and energy applications: Fundamentals, recent advances and applications

Owing to their unique properties, the electrochemically self-organized TiO2 nanotube arrays (TNTAs) have attracted great attention as promising nanomaterials for energy and environmental photocatalytic applications. This has stimulated intensive research activities that focused on the synthesis, properties, modification and applications of these 1D nanomaterials as photocatalysts. In this review, all these aspects are fully covered in a comprehensive way that was not presented previously. The review starts with discussing the main fundamentals of the photocatalytic process using TNTAs. Then, the recent developments in the synthesis methods and modification strategies of TNTAs are presented in detail. The main photocatalytic applications of TNTAs including CO2 reduction, H2 and O2 production and pollutants degradation are also summarized, taking into consideration the research studies conducted in the last 10 years. Finally, the challenges and future recommendations for the use of TNTAs are highlighted. This review aims to provide an insightful step forward to a better understanding of TNTAs-based nanomaterials and their use as proficient photocatalysts in the future

Optimization of anodizing parameters for the morphological properties of TiO2 nanotubes based on response surface methodology

TiO2 nanotube (TNT) morphology is crucial for applications in a variety of fields. In this paper, response surface methodology (RSM) has been utilized to optimize the anodizing parameters i.e., electrolyte concentration (C), anodization voltage (V), and time (t) for morphology (e.g., nanotube diameter and length) of TNTs. Ethylene glycol (EG) based electrolyte has been used for anodization employing ammonium fluoride (NH4F) as a source of fluoride ion (F–) with 2.5 vol% H2O. Reliable regression models have been developed between the input variables and the corresponding responses, namely tube diameter and length with multiple regression coefficients of 0.9649 and 0.9253, respectively, revealing a trustworthy association between the actual and those predicted values using the quadratic model. The predicted values of C (0.31 wt%), V (38.44 V), and t (69.37 min) were found to be the optimum anodization condition preceding a TiO2 nanotubes diameter of 99.31 nm and length of 4572.64 nm. It was observed that the nanotubes diameter and length are more affected by anodizing voltage and time, and less sensitive to NH4F concentration. Therefore, RMS could be an appropriate technique to optimize anodizing parameters for producing TiO2 nanotubes with good morphology

A comprehensive review on advances in TiO2 nanotube (TNT)-based photocatalytic CO2 reduction to value-added products

The photocatalytic reduction of CO2 into solar fuels by using semiconductor photocatalysts is one of the most promising approaches in terms of pollution control as well as renewable energy sources. One of the crucial challenges for the 21st century is the development of potential photocatalysts and techniques to improve CO2 photoreduction efficiency. TiO2 nanotubes (TNTs) have recently attracted a great deal of research attention for their potential to convert CO2 into useful compounds. Researchers are concentrating more on CO2 reduction due to the rising trend in CO2 emissions and are striving to improve the rate of CO2 photoreduction by modifying TNTs with the appropriate configuration. In order to portray the potential applications of TNTs, it is imperative to critically evaluate recent developments in synthesis and modification methodologies and their capability to transform CO2 into value-added chemicals. The current review provides an insightful understanding of TNT production methods, surface modification strategies used to enhance CO2 photoreduction, and major findings from previous research, thereby revealing research gaps and upcoming challenges. Stability, reusability, and the improved performance of TNT photocatalysts under visible light as well as the selection of optimized modification methods are the identified barriers for CO2 photoreduction into valuable products. Higher rates of efficacy and product yield can be attained by synthesizing suitable photocatalysts with addressing the limitations of TNTs and designing an optimized photoreactor in terms of the proper utilization of photocatalysts, incident lights, and the partial pressure of reactants

Recent progress in TiO2-Based photocatalysts for conversion of CO2 to hydrocarbon fuels: A systematic review

Photocatalytic conversion of CO2 by using sunlight and TiO2 photocatalysts is a promising approach which produce hydrocarbon fuels to meet the future energy demands with hardly affecting the environment. This systematic review aims to provide rigorous overview of recent progress in TiO2-based CO2 photoreduction to produce hydrocarbon fuels along with future challenges. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method was adopted to perform this systematic review. It uses explicit systematic approaches that are chosen to prevent bias, resulting in accurate data collection which helps to draw reliable conclusions. Peer-reviewed articles published in English language between year 2018–2022 were chosen from two main databases, namely Web of Science and Scopus. Depending on the search criteria 62 articles were selected for reviewing critically. Literature suggests that TiO2-based photocatalysts have been increasingly used for reducing CO2 to hydrocarbon fuels. Morphological alterations and surface modification techniques have been widely utilized to improve the photocatalytic performance and minimize limitations of pure TiO2. Despite extensible efforts in this field, the utilization of hydrocarbon fuels still far away from practical applications. There are some challenges need to be addressed like environment friendly low-cost synthesis and modification method development, maximum visible light utilization, design of photoreactor with suitable product selectivity and kinetic model development for CO2 reduction. This study portrays increased clarity regarding the advances and way forwards of crucial topics TiO2-based CO2 photoreduction. Such systematic review is crucial for researchers and academicians for setting future planning