133 research outputs found
Engineered Material from Natural Fibre for Interior Design Applications
Some natural fibres including jute, flax, hemp, kenaf and sisal have been found very promising for potential applications as reinforcement in engineered composite materials. The environmental drivers, such as ability to absorb CO2 during production in contrary to synthetic materials and having non-toxic characteristics, have made them ideal candidates for incorporation into composites for industrial and technical applications that do not require very high mechanical resistance, for examples, window and doorframes, indoor furniture panels, automotive panels and upholstery, parcel shelves, noise insulating panels etc. This paper discusses fabrication and mechanical performance testing of multi-layered jute fabrics reinforced thermoplastic composite material. Jute hessian fabrics were sandwiched in 0° orientation into several layers of High Density Polyethylene (HDPE) polymeric sheets and pressed at high temperature and pressure to form composite laminates. Microscopic analysis revealed that the fibre and yarn orientation of fabrics within composite remained intact and no visible void was identified. Mechanical performance of the composites having a small percentage of fibre content was found to have improved significantly when compared to the pure HDPE laminates. The tensile and flexural strength of the laminate composite with optimum number of layers (6-layer makes a weight fraction of 18.50%) were improved by more than 50%, while flexural modulus was also increased significantly. Fracture morphology of the composite investigated by a Scanning Electron Microscope (SEM) showed good adhesion of the jute fabrics with the polymer matrices
Development and characterisation of multilayer jute fabric reinforced HDPE composites
The bast fibres, a subgroup of natural fibre family, have emerged as a strong competitor of widely used man-made glass fibre for use as fillers or reinforcing materials in certain types of composite materials, which do not require very high mechanical resistance. This paper investigates manufacturing of multi-layered jute fabric reinforced thermoplastic composite and its mechanical performance. Hessian jute fabrics in 2, 4 and 6 layers without any pre-treatment were sandwiched in 0° orientation into seven layers of High-Density Polyethylene (HDPE) sheets and pressed at high temperature and pressure to form composite laminates having three different structural designs. The laminates with 2, 4 and 6 layers contain approximately 6.70 wt%, 12.90 wt%, and 18.50 wt% of jute fibres respectively. Mechanical performance of the composite laminates having 4 and 6 layers of jute fabric was found to have improved significantly when compared to the pure HDPE laminates. Within a given sample thickness of 6.5 mm, the laminate with 6-layers of jute fabric exhibited the best mechanical performance. Optical microscopic analysis revealed that the yarn orientation of the fabrics within the composites remained stable and there was no visible void in the laminate structure. Fracture morphology of the composite investigated by a Scanning Electron Microscope (SEM) showed good adhesion of the jute fabrics with the HDPE matrix
Current development and future perspective on natural jute fibers and their biocomposites
The increasing trend of the use of synthetic products may result in an increased level of pollution affecting both the environment and living organisms. Therefore, from the sustainability point of view, natural, renewable and biodegradable materials are urgently needed to replace environmentally harmful synthetic materials. Jute, one of the natural fibers, plays a vital role in developing composite materials that showed potential in a variety of applications such as household, automotive and medical appliances. This paper first reviews the characterization and performance of jute fibers. Subsequently, the main focus is shifted towards research advancements in enhancing physical, mechanical, thermal and tribological properties of the polymeric materials (i.e., synthetic or biobased and thermoplastic or thermoset plastic) reinforced with jute fibers in a variety of forms such as particle, short fiber or woven fabric. It is understood that the physio-mechanical properties of jute-polymer composites largely vary based on the fiber processing and treatment, fiber shape and/or size, fabrication processes, fiber volume fraction, layering sequence within the matrix, interaction of the fiber with the matrix and the matrix materials used. Furthermore, the emerging research on jute fiber, such as nanomaterials from jute, bioplastic packaging, heavy metal absorption, electronics, energy device or medical applications and development of jute fiber composites with 3D printing, is explored. Finally, the key challenges for jute and its derivative products in gaining commercial successes have been highlighted and potential future directions are discussed
Framework for Environmentally Sustainable Fashion and Textile Production to achieve United Nation (UN) Sustainable Development Goal (SDG) 12
A framework with three key actions - identify (I), act (A), and evaluate (E) to achieve complete environmental sustainability in fashion and textile production in line with SDG 12– has been developed as a part of a Global Challenge Research Fund (GCRF) project. Called as the ‘I-A-E framework’, it emphasises more on zero or near-zero waste generation at source and incorporating sustainability thinking in material and process selections, rather than post-production waste management after generating huge amounts of wastes and effluents. The first step involves ‘identifying’ present scenarios and points of action in context of resource consumption, air pollution and greenhouse gas emissions, water pollution, and solid waste generation in product development and production. The next step is to ‘act’ for sustainable development, which includes - incorporating a zero-waste philosophy during production, incorporating sustainability thinking into material selection and incorporating sustainability into production process, incorporating sustainability in resource and waste management. The third component of the framework is to ‘evaluate’ to celebrate and move forward by checking the eco-indices to amend targets or set new ones. This new framework was validated through stakeholders’ workshops and roundtable discussion. It is an easy-to-follow toolkit that the fashion and textile industry will be able to implement into their product development and production activities
Assessing Mechanical Properties of Jute, Kenaf, and Pineapple Leaf Fiber-Reinforced Polypropylene Composites: Experiment and Modelling
The application of natural fibers is increasing rapidly in the polymer-based composites. This study investigates manufacturing and characterization of polypropylene (PP) based composites reinforced with three different natural fibers: jute, kenaf, and pineapple leaf fiber (PALF). In each case, the fiber weight percentages were varied by 30 wt.%, 35 wt.%, and 40 wt.%. Mechanical properties such as tensile, flexural, and impact strengths were determined by following the relevant standards. Fourier transform infrared (FTIR) spectroscopy was employed to identify the chemical interactions between the fiber and the PP matrix material. Tensile strength and Izod impact strength of the composites significantly increased for all the composites with different fiber contents when compared to the pure PP matrix. The tensile moduli of the composites were compared to the values obtained from two theoretical models based on the modified “rule of mixtures” method. Results from the modelling agreed well with the experimental results. Tensile strength (ranging from 43 to 58 MPa), flexural strength (ranging from 53 to 67 MPa), and impact strength (ranging from 25 to 46 kJ/m2) of the composites significantly increased for all the composites with different fiber contents when compared to the pure PP matrix having tensile strength of 36 MPa, flexural strength of 53 Mpa, and impact strength of 22 kJ/m2. Furthermore, an improvement in flexural strength but not highly significant was found for majority of the composites. Overall, PALF-PP displayed better mechanical properties among the composites due to the high tensile strength of PALF. In most of the cases, T98 (degradation temperature at 98% weight loss) of the composite samples was higher (532–544 °C) than that of 100% PP (500 °C) matrix. Fractured surfaces of the composites were observed in a scanning electron microscope (SEM) and analyses were made in terms of fiber matrix interaction. This comparison will help the researcher to select any of the natural fiber for fiber-based reinforced composites according to the requirement of the final product
Ambient particle inhalation and the cardiovascular system: potential mechanisms
Well-documented air pollution episodes throughout recent history have led to deaths among individuals with cardiovascular and respiratory disease. Although the components of air pollution that cause the adverse health effects in these individuals are unknown, a small proportion by mass but a large proportion by number of the ambient air particles are ultrafine, i.e., less than 100 nm in diameter. This ultrafine component of particulate matter with a mass median aerodynamic diameter less than 10 microm (PM(10) may mediate some of the adverse health effects reported in epidemiologic studies and for which there is toxicologic evidence to support this contention. The exact mechanism by which ultrafine particles have adverse effects is unknown, but these particles have recently been shown to enhance calcium influx on contact with macrophages. Oxidative stress is also to be anticipated at the huge particle surface; this can be augmented by oxidants generated by recruited inflammatory leukocytes. Atheromatous plaques form in the coronary arteries and are major causes of morbidity and death associated epidemiologically with particulate air pollution. In populations exposed to air pollution episodes, blood viscosity, fibrinogen, and C-reactive protein (CRP) were higher. More recently, increases in heart rate in response to rising air pollution have been described and are most marked in individuals who have high blood viscosity. In our study of elderly individuals, there were significant rises in CRP, an index of inflammation. In this present review, we consider the likely interactions between the ultrafine particles the acute phase response and cardiovascular disease
The burden of diseases and risk factors in Bangladesh, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019
Background: Bangladesh has made substantial progress in improving socioeconomic and health indicators over the past 50 years, but data on national disease burden are scarce. We used data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to estimate the burden of diseases and risk factors in Bangladesh from 1990 to 2019. / Methods: For this systematic analysis, we analysed data from vital registration systems, surveys, and censuses using multistage modelling processes to estimate life expectancy at birth, mortality rate, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs). Additionally, we compared the health status of Bangladesh with that of the other countries in the GBD south Asia region—Bhutan, India, Nepal, and Pakistan. / Findings: Life expectancy at birth in Bangladesh increased from 58·2 years (95% uncertainty interval 57·1–59·2) in 1990 to 74·6 years (72·4–76·7) in 2019. Between 1990 and 2019, the age-standardised mortality rate decreased from 1509·3 (1428·6–1592·1) to 714·4 (604·9–838·2) deaths per 100 000 population. In 2019, non-communicable diseases represented 14 of the top 20 causes of death; the leading three causes were stroke, ischaemic heart disease, and chronic obstructive pulmonary disease. High blood pressure, high fasting plasma glucose, and smoking were the top three risk factors. From 1990 to 2019, the rate of all-cause DALYs decreased by 54·9% (48·8–60·4). In 2019, the leading causes of DALYs and YLLs were neonatal disorders, stroke, and ischaemic heart disease, whereas musculoskeletal disorders, depressive disorders, and low back pain were the leading causes of YLDs. Bangladesh has the lowest age-standardised rates of mortality, YLDs, and YLLs and the highest life expectancy at birth in south Asia. / Interpretation: Over the past 30 years, mortality rates have reduced by more than half in Bangladesh. Bangladesh must now address the double burden of communicable and non-communicable diseases. Cost-effective, multisectoral efforts are needed to prevent and control non-communicable diseases, promote healthy lifestyles, and prevent premature mortality and disabilities. / Funding: Bill & Melinda Gates Foundation. / Translation: For the Bangla translation of the abstract see Supplementary Materials section
XMIAR: X-ray medical image annotation and retrieval
The huge development of the digitized medical image has been steered
to the enlargement and research of the Content Based Image Retrieval (CBIR)
systems. Those systems retrieve and extract the images by their own low level
features, like texture, shape and color. But those visual features did not aloe the
users to request images by the semantic meanings. The image annotation or
classification systems can be considered as the solution for the limitations of the
CBIR, and to reduce the semantic gap, this has been aimed annotating or to make
the classification of the image with few controlled keywords. In this paper, we
suggest a new hierarchal classification for the X-ray medical image using the
machine learning techniques, which are called the Support Vector Machine
(SVM) and k-Nearest Neighbour (k-NN). Hierarchy classification design was
proposed based on the main body region. Evaluation was conducted based on
ImageCLEF2005 database. The obtained results in this research were improved
compared to the previous related studies
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