RESUMO
Informal incineration or open pit burning of waste materials is a common practice in the peripheral area of Dhaka, one of the fastest growing mega-cities in the world. This study deals with the effect of open pit burned (i.e. open burned) household waste bottom ash on ï¬red clay bricks. Between 0 to 50% (by weight) of open pit burned household waste bottom ash was mixed with clay to make bricks. The molded specimens were air-dried at room temperature for 24 h and then oven dried at 100 °C for another 24 h to remove the water. The raw bricks were fired in a muffle furnace to a designated temperature (800, 900 and 1000 °C, respectively). The firing behaviour (mechanical strength, water absorption and shrinkage) was determined. The microstructures, phase compositions and leachates were evaluated for bricks manufactured at different firing temperatures. These results demonstrate that open pit burned ash can be recycled in clay bricks. This study also presents physical observations of the incinerated ash particles and determination of the chemical compositions of the raw materials by wet analysis. Open pit burned ash can be introduced easily into bricks up to 20% wt. The concentrations of hazardous components in the leachates were below the standard threshold for inert waste category landfill and their environmental risk during their use-life step can be considered negligible.
Assuntos
Materiais de Construção/análise , Incineração , Reciclagem , Resíduos/análise , Silicatos de Alumínio/análise , Bangladesh , Cidades , Argila , Cinza de Carvão/análise , Estudos de ViabilidadeRESUMO
There is a great demand for biodegradable hydrogel, and cellulose enriched wastes materials are widely used to serve this purpose for various advance applications (e.g., biomedical and environmental). Sugarcane bagasse is cellulose-enriched agro-waste, abundantly grown in Bangladesh. This study aimed to treat sugarcane bagasse-based agro-waste using a sustainable and ecofriendly approach to produce hydrogel with super-swelling capacity for adsorption of copper, chromium, iron ions, methylene blue and drimaren red dyes. To increase the swelling property of hydrogels, copolymerization of hydrophilic monomers is an effective technique. Therefore, this study aimed to prepare hydrogel via free radical graft-copolymerization reaction among acrylamide, methyl methacrylate and treated bagasse in the presence of N,N-methylene-bis-acrylamide as a crosslinker and potassium persulphate as an initiator. To obtain maximum yield, reaction conditions were optimized. It was found that hydrogel obtained from chemically treated sugarcane bagasse showed maximum water absorption capacity of 228.0 g/g, whereas untreated bagassebased hydrogel could absorb ~50 g/g of water. Maximum adsorption capacity of 247.0 mg/g was found for copper ion. In addition, organic pollutant removal from industrial effluent also showed good performance, removing >90% of methylene blue and 62% of drimaren red dye, with shorter kinetics. The biodegradability study showed that after 90 days of exposure, the hydrogels degraded to about 43% of their own mass. Therefore, the produced hydrogel could be an alternative adsorbent to remove pollutants and also for other potential applications.
RESUMO
AIM: The aim of this research is to focus on gaining an insight into the knowledge, attitudes, behavioural practises (KAP), and psychological impact relating to COVID-19 among the people living with spinal cord injury receiving in-patient rehabilitation. METHODS: A prospective, cross-sectional survey of people with SCI (N = 207), who were in active in-patient rehabilitation from two tertiary SCI Rehabilitation Centres in Bangladesh. Data were collected via face-to-face interviews, after voluntary consent, using a pretested, language validated questionnaire on Knowledge, Attitude and Behavioural practises (KAP) and the Depression, Anxiety, Stress Scale (DASS-21). Ethical approval and trial registration were obtained prospectively. RESULTS: A total of 207 people with SCI responded, among which 87% were men and 13% were women, with a mean age of 34.18 ± 12.9 years. Within the sample group, people living with tetraplegia comprised 33.8%, and people living with paraplegia comprised 66.2%. Overall, 63.8% of the participants were diagnosed with an SCI categorised as ASIA-A. Overall, the "knowledge score" was 8.59 ± 2.3 out of 12, "depression" was 11.18 ± 8, "anxiety" was 7.72 ± 5.1, and "stress" was 9.32 ± 6.7 from a total of 21 scores each category. The strong correlation was between knowledge, DASS scores, and age (p < 0.05). In addition, there was a strong correlation between knowledge, gender (p < 0.05) and education (p < 0.01). Binary logistic regression found a stronger association of knowledge and DASS scores with gender, young age, illiteracy (p < 0.01), and rural residence (p < 0.05). A positive relationship was found between depression and anxiety scores (p < 0.01) and a moderate positive relationship was found between depression and stress scores (p < 0.01). A positive attitude was reported by the majority of participants (p < 0.05). In terms of behavioural practises, participants reported both self and caregiver had followed health advice with regard to consulting health professionals (65.7%), implementing isolation (63.8%), taking droplet precaution care (87.4%), and hygiene care (90.3%). CONCLUSION: Participants in this study reported high levels of knowledge, adoption of positive attitudes, and the practise of positive health advisory behaviours related to COVID-19 prevention procedures. However, high levels of depression, anxiety, and stress were also reported. Overall, women and younger participants were more likely to have high KAP, whereas those living in rural areas and with literacy challenges were less likely to report high knowledge scores.
RESUMO
The study aims to determine the level of Knowledge, Attitude, and Practice (KAP) related to COVID-19 preventive health habits and perception of fear towards COVID-19 in subjects living in Bangladesh. DESIGN: Prospective, cross-sectional survey of (n = 2157) male and female subjects, 13-88 years of age, living in Bangladesh. METHODS: Ethical approval and trial registration were obtained before the commencement of the study. Subjects who volunteered to participate and signed the informed consent were enrolled in the study and completed the structured questionnaire on KAP and Fear of COVID-19 scale (FCV-19S). RESULTS: Twenty-eight percent (28.69%) of subjects reported one or more COVID-19 symptoms, and 21.4% of subjects reported one or more co-morbidities. Knowledge scores were slightly higher in males (8.75± 1.58) than females (8.66± 1.70). Knowledge was significantly correlated with age (p < .005), an education level (p < .001), attitude (p < .001), and urban location (p < .001). Knowledge scores showed an inverse correlation with fear scores (p < .001). Eighty-three percent (83.7%) of subjects with COVID-19 symptoms reported wearing a mask in public, and 75.4% of subjects reported staying away from crowded places. Subjects with one or more symptoms reported higher fear compared to subjects without (18.73± 4.6; 18.45± 5.1). CONCLUSION: Bangladeshis reported a high prevalence of self-isolation, positive preventive health behaviors related to COVID-19, and moderate to high fear levels. Higher knowledge and Practice were found in males, higher education levels, older age, and urban location. Fear of COVID-19 was more prevalent in female and elderly subjects. A positive attitude was reported for the majority of subjects, reflecting the belief that COVID-19 was controllable and containable.