End-Of-Life Textiles as Reinforcements in Biocomposites

A number of attempts have been made to recycle cotton/polyester blend woven fabrics after use; however, most of these fabrics are disposed of in landfills. Major part of these blend fabrics are not recycled due to complexity of the fibre arrangement and cannot be separated economically. This study shows that these discarded woven fabrics could be directly used as reinforcements in composites without fibre separation. Uniform alignment in the woven fabric provided consistent properties to the composites. The fabrics were reinforced by soybean-based-bioresins to produce biocomposites. The composites were analysed for mechanical, thermal, viscoelastic and morphological properties. Porosity and wettability of the composites were also evaluated. Results demonstrate that the tensile strength and modulus of over 100 and 10 MPa, respectively, can be obtained without any fibre treatment. Furthermore, impact strength over 70 kJ/m² was obtained without any chemical treatment on fibres. The porosity of the composites produced was less than 9 vol%. Additionally, the fabrics were treated with alkali in order to improve the fibre–matrix interface and the composite properties were studied. From the economical perspective, these composites can be produced at a low cost as the major component is available for free or low cost.     

Design and Characterization of PVA–Methacrylic Acid Based Smart Polymeric System for Controlled Release of Metoprolol

In the present work covalently crosslinked smart polymeric system of hydrogel based on poly vinyl alcohol (PVA) and methacrylic acid (MA) was designed by free radical polymerization with different compositions using glyoxal (40 % water solution) as crosslinker. It was observed that swelling of hydrogel had a pronounced enhancing effect on increasing the concentration of MA due to availability of more ionized carboxylic groups of MA but produced an opposite effect on increasing the concentration of glyoxal owing to less porous structure. As far as PVA is concerned, swelling did not show significant effect on increasing the concentration of PVA. Hydrophilic polymer PVA rich in hydroxyl group pertained to be highly interactive with water. It was examined that the release of metoprolol tartrate decreased with increased concentration of glyoxal, but increased with increase in concentration of MA. PVA/MA hydrogel was characterized by Fourier transform infrared spectroscopy and X-ray diffraction to study the structure and crystallinity of hydrogel respectively. Morphology was studied through scanning electron microscopy. Furthermore differential scanning calorimetry and thermogravimetric analysis were also performed to characterize thermal stability. It may be concluded that the mechanism of drug release was mainly non-Fickian diffusion.     

The invasion paradox: reconciling pattern and process in species invasions

The invasion paradox describes the co-occurrence of independent lines of support for both a negative and a positive relationship between native biodiversity and the invasions of exotic species. The paradox leaves the implications of native-exotic species richness relationships open to debate: Are rich native communities more or less susceptible to invasion by exotic species? We reviewed the considerable observational, experimental, and theoretical evidence describing the paradox and sought generalizations concerning where and why the paradox occurs, its implications for community ecology and assembly processes, and its relevance for restoration, management, and policy associated with species invasions. The crux of the paradox concerns positive associations between native and exotic species richness at broad spatial scales, and negative associations at fine scales, especially in experiments in which diversity was directly manipulated. We identified eight processes that can generate either negative or positive native-exotic richness relationships, but none can generate both. As all eight processes have been shown to be important in some systems, a simple general theory of the paradox, and thus of the relationship between diversity and invasibility, is probably unrealistic. Nonetheless, we outline several key issues that help resolve the paradox, discuss the difficult juxtaposition of experimental and observational data (which often ask subtly different questions), and identify important themes for additional study. We conclude that natively rich ecosystems are likely to be hotspots for exotic species, but that reduction of local species richness can further accelerate the invasion of these and other vulnerable habitats.     

Parameters effect on heterogeneous photocatalysed degradation of phenol in aqueous dispersion of TiO_2

In this study, photocatalytic degradation of phenol selected as model compound of organic pollutant had been investigated in aqueous titanium dioxide (TiO2) dispersion under UV irradiation. The effects of various parameters such as pH, catalyst concentration, phenol concentration, anions, metal ions, electron acceptors, and surfactants on the photocatalytic degradation of phenol were investigated. The degradation kinetics was determined by the change in phenol concentration employing UV-Vis spectrometry as a function of irradiation time. The degradation kinetics of phenol follows pseudo first-order kinetics. The results showed a significant dependence of the photocatalytic degradation of phenol on the functional parameters. The probable promising roles of the additives on the degradation process were discussed.     

Water quality in rice-growing watersheds in a Mediterranean climate

Rice (Oryza sativa L.) agriculture is estimated to cover 161 million ha of land on Earth, with 10% grown in temperate regions. Currently there are strong concerns about surface water nutrient pollution, and the purpose of this study was to determine the impacts of temperate rice cultivation on nutrient dynamics at the small watershed scale. Over the course of the 2008 growing season (May through September), bi-weekly grab samples were collected from outlets of 11 agricultural subwatersheds in California. Samples were analyzed for NO₃-N, NH₄-N, PO₄-P, K, and dissolved organic nitrogen (DON) concentrations, and the average values across all subwatersheds and sampling dates were 0.22, 0.031, 0.047, 1.36, and 0.32 mg L⁻¹, respectively. Linear mixed effects analysis was used to evaluate the magnitude of relationships between nutrient concentration and flux and subwatershed characteristics (i.e. percent soil clay and organic matter, percent rice area, irrigation water reuse, subwatershed discharge, irrigated area, and time, measured as the day in the growing season). For all nutrients, flux decreased over time and increased with discharge. Concentrations of K and DON were highest at the start and end of the growing season. Concentrations of NH₄-N were near non-detect levels, with the exception of a peak in mid-July, which corresponds to when many growers top-dress rice fields with N fertilizer. Nitrate-N concentration and flux decreased with percent rice area, whereas PO₄-P concentrations increased with percent rice area, indicating that rice area should be considered in future watershed-scale studies of nutrient discharge. In all subwatersheds, the discharge loads of K were smaller than surface water input loads, while NO₃-N, NH₄-N, PO₄-P, and DON discharge loads exceeded input loads when total growing season discharge was greater than 3500-6600 m³ ha⁻¹. This implies that the management of subwatershed discharge can be used to control nutrient export from rice-growing areas.     

Impacts of continuously regenerating trap and particle oxidation catalyst on the NO2 and particulate matter emissions emitted from diesel engine

Two continuously regenerating diesel particulate filter (CRDPF) with different configurations and one particles oxidation catalyst (POC) were employed to perform experiments in a controlled laboratory setting to evaluate their effects on NO₂, smoke and particle number emissions. The results showed that the application of the after-treatments increased the emission ratios of NO₂/NO_x significantly. The results of smoke emissions and particle number (PN) emissions indicated that both CRDPFs had sufficient capacity to remove more than 90% of total particulate matter (PM) and more than 97% of solid particles. However, the POC was able to remove the organic components of total PM, and only partially to remove the carbonaceous particles with size less than 30 nm. The negligible effects of POC on larger particles were observed due to its honeycomb structure leads to an inadequate residence time to oxidize the solid particles or trap them. The particles removal efficiencies of CRDPFs had high degree of correlations with the emission ratio of NO₂/NO_x. The PN emission results from two CRDPFs indicated that more NO₂ generating in diesel oxidation catalyst section could obtain the higher removal efficiency of solid particles. However this also increased the risk of NO₂ exposure in atmosphere.     

"草原110"

为进一步增强牧区社会治安整体防控能力,不断提高公安机关接警、出警、处警快速反应能力,切实解决牧区报警难等问题,2004年内蒙古阿鲁科尔沁旗综合办在全旗8个苏木镇、27个嘎查启动了“草原110”报警、巡逻防范体系,并分南北两片在道德镇和罕苏木举行了“草原110”启动仪式。目前这支队伍共有126人,35辆巡逻车。昼夜活动在牧区的各嘎查村和放牧点。上岗仅一个月,这支联防队伍在巡逻、守候、     

蒙古族的射箭

射箭,在中国的蒙古族有着悠久的历史。在蒙元时期,成吉思汗曾规定：“每个战士必须带有下列武器：弓二张至三张,其中至少有一张好弓,三个装满箭的大箭筒”。     

Monitoring of growth and physiological activities of biofilm during succession on polystyrene from activated sludge under aerobic and anaerobic conditions

The present research work monitored the successive biofilm development and its catabolic role in the degradation of polystyrene (PS). PS material was artificially colonized with biofilm by incubating it with activated sludge under aerobic and anaerobic conditions. Biofilm formation was monitored by gravimetric weight analysis, spectrophotometric absorbance technique, heterotrophic plate count, and scanning electron microscopy under aerobic and anaerobic conditions. The wet weight (1.59 and 1.17 g) and dry weight (0.41 and 0.08 g) of a biofilm showed a significant constant increase under aerobic and anaerobic conditions, respectively, from first till 9 weeks of incubation. Plate count of the selected bacteria (Escherichia coli, Salmonella typhimurium, Shigella dysenteriae, Pseudomonas aeruginosa) considerably declined (90–99 %) in the biofilm after seventh and fifth weeks of incubation under aerobic and anaerobic conditions, respectively, indicating a positive shift from pathogenic to beneficial microbial community. While most probable number index of fecal coliforms and E. coli in the sludge showed more reduction (98 and 99 %) under aerobic as compare to anaerobic conditions (86 and 91 %) after 9 weeks of biofilm formation on PS cubes. Correspondingly, the decreasing levels of chemical oxygen demand and biochemical oxygen demand (up to 73 %) showed signs of sludge digestion. Scanning electron microscope coupled with energy dispersive X-ray spectroscope revealed nature of PS media containing high carbon content. However, biofilm development proved to be involved in the biochemical transformation of the PS medium as indicated by Fourier transform infrared spectroscopy.