This present study deals with evaluating some available rice by-products, such as rice straw and rice husks, as a fiber component in manufacturing of high performance natural fiber polymer composites (NFPC). The utilization of these undesirable wastes will contribute to the reduction of the environmental impact of waste disposal by burning. Two matrices (thermoset and thermoplastic) were used. Optimization of manufacture conditions of polyester-based thermosetting polymer composites was carried out through examine the effects of fibers to polymer ratio, amounts of catalyzed and initiator, fraction size of fibers and substituting one fibers by another, as well as time, temperature and pressure of pressing. The possibility of styrene containing polyester solution on improving the fiber interface via in situ grafting and enhancing the strength and water resistance of the produced NFPC was also evaluated, in comparison with that produced from using thermoplastic matrix (polypropylene) in presence of coupling agent. The production of this valuable product (NFPC) by this simple procedure, which not needs special devices (twin extrusion with heater), and chemicals to improve the compatibility between fibers and polymer matrix, will ensure reasonable profits and direct impacts on the Egyptian economy in general and rice growers in particular. 相似文献
Ethyl alcohol, acetone, and petroleum ether extracts of three plant species belonging to three different botanical families [Strychnos nux-vomica (Loganiaceae), Euphorbia lathyrus (Euphorbiaceae), and Datura stramonlum (Solanaceae)], a chemical insecticide; profenofos and their combinations were tested against second and fourth instars of Spodoptera littoralis under lab conditions. Results revealed that the ethanol extract of S. nux-vomica was the most effective among all plant extracts, where the corrected mortality% were 92, 81, 58, and 27% to 2nd instar and 89, 74, 34, and 11% to 4th instar at concentrations 0.5, 0.25, 0.125, and 0.0625%, respectively. Calculated LC50's were 0.11, 0.22, and 0.34% to 2nd instar and 0.17, 0.37, and 0.52% to 4th instar for ethanol, petroleum ether, and acetone extracts, respectively. Acetone extracts of all plants were of lower effect. The chemical insecticide profenofos displayed higher efficacy than plant extracts (LC50 = 0.002 and 0.003% for S. littoralis 2nd and 4th larval instars, respectively). The co-toxicity factor reached 76 and 60 when mixing S. nux-vomica + profenofos and D. stramonlum + profenofos at ratio 1:1 against S. littoralis 2nd instar larvae, thus indicating a potentiating effect. While treatment of the 4th instar larvae by the same mixtures resulted in a co-toxicity factor below 20 at all mixing ratios indicating, only, an additive effect against this instar. 相似文献
Phenanthrene and methyl-phenanthrenes are major aromatic pollutants originating in particular from fuel oil. Phenanthrene is usually degraded faster than methyl-phenanthrenes under geological and environmental conditions. Here, we report a preferential and accelerated biodegradation of methyl-phenanthrenes versus phenanthrene in soil contaminated by fuel oil. The polluted soil was mixed with sawdust and sand to form a homogenized biopile. The biopile was continuously sprayed with microbial consortia isolated from crude oil?Ccontaminated soil and treated by biosurfactants and nutritive substances for biostimulation. During a 6-month bioremediation experiment, a steady increase in the relative abundance of phenanthrene compared to methyl-phenathrenes was observed by gas chromatography?Cmass spectrometry. The increase was the highest for trimethyl-phenanthrenes, with a phenanthrene/trimethyl-phenanthrenes ratio increasing from 0.42 to 2.45. By contrast, the control, non-stimulated samples showed a ratio decrease from 0.85 to 0.11. Moreover, the results showed that the level of degradability depends on the number of methyl groups. 相似文献
Microwave irradiation has been used to prepare Al, Fe-pillared clays from a natural Tunisian smectite from the El Hicha deposit (province of Gabes). Chemical analysis, XRD spectra and surface properties evidenced the success of pillaring process. The obtained solids present higher surface area and pore volume than conventionally prepared Al-Fe pillared clays. The main advantages of the microwave methodology are the considerable reduction of the synthesis time and the consumption of water. The microwave-derived Al-Fe pillared clays have been tested for catalytic wet air oxidation (CWAO) of phenol in a stirred tank at 160°C and 20 bar of pure oxygen pressure. These materials are efficient for CWAO of phenol and are highly stable despite the severe operating conditions (acidic media, high pressure, high temperature). The catalyst deactivation was also significantly hindered when compared to conventionally prepared clays. Al-Fe pillared clays prepared by microwave methodology are promising as catalysts for CWAO industrial water treatment.
Journal of Polymers and the Environment - The aim of this study is to investigate the effect of fiber length and loading on physico-mechanical and flammability properties of Cyrtostachys renda (CR)... 相似文献
Journal of Polymers and the Environment - A Green nanomaterial synthesis could be considered as an alternative bio-controller source of insect pest management as well as saving the environment.... 相似文献
Journal of Material Cycles and Waste Management - In this study, a mechanochemical activation technique to effectually extract lead from the funnel glass of cathode ray tube (CRT) is proposed. A... 相似文献
Natural hazard analysis involves mapping and identifying future hazardous zones through the analysis of the controls influencing
hazard initiation and occurrence. One of such natural hazard is the landslide. Landslides are amongst the most costly and
damaging natural hazards especially in mountain regions and are triggered mainly by seismic activity and/or rainfall. The
aim of the present study is to integrate Remote Sensing (RS) and Geographic Information System (GIS) tools to create thematic
layers for assessment and the estimation of landslide hazard zones in and surrounding the Wadi Watier area, South Sinai, Egypt.
Various factors, variables and/or parameters can be derived from thematic layers such as lithology, structural lineaments,
land-cover/land-use, terrain analysis and earthquakes. Intensity risk layers were created by using ERDAS Imagine 9.2, ARC
GIS 9.2 and ARC INFO 7.2.1 software. Enhanced Thematic Mapper (ETM+7) Landsat satellite images were used to discriminate and
extract structural lineaments, lithology and land-use/land-cover variables for the study area. The Digital Elevation Model
(DEM) was generated from digitized topographic maps to produce terrain analysis maps such as; slope, aspect, height elevation,
and 3D. The weighting score rating system based on the relative importance of various causal factors derived from RS data
and other thematic layers was used for landslide hazard zonation (LHZ). Based on these data, a simple algorithm was created
to classify the area into different risk zones. By overlaying all hazard layers a final landslide hazard map was produced.
Using trial and error and statistical methods the weight score rating values have been readjusted. GIS integration with RS
data can greatly facilitate classifying landslide hazard zones into low risk, moderate risk and high risk by using a slicing
operation. Seismic data are integrated with final the LHZ to generate a LHZ scenario map for the future and to draw up an
action plan of mitigation measures to avoid the damage, loss of life and socio-economic impacts in the study area. 相似文献
Analysis of both the crash count and the severity of injury are required to provide the complete picture of the safety situation of any given roadway. The randomness of crashes, the one-way dependency of injury on crash occurrence and the difference in response types have typically led researchers into developing independent statistical models for crash count and severity classification. The Genetic Programming (GP) methodology adopts the concepts of evolutionary biology such as crossover and mutation in effectively giving a common heuristic approach to model the development for the two different modeling objectives. The chosen GP models have the highest hit rate for rear-end crash classification problem and the least error for function fitting (regression) problems. Higher Average Daily Traffic (ADT) is more likely to result in more crashes. Absence of on-street parking may result in diminished severity of injuries resulting from crashes as they may provide “soft” crash barrier in contrast to fixed road side objects. Graphical presentation of the frequency of crashes with varying input variables shed new light on the results and its interpretation. Higher friction coefficient of roadways result in reduced frequency of crashes during the morning peak hours, with the trend being reversed during the afternoon peak hours. Crash counts have been observed to be at a maximum at a surface width of 30 ft. Sensitivity analysis results reflect that ADT is responsible for the largest variation in crash counts on urban arterials. 相似文献