982 resultados para Mmineral dust
Resumo:
A procedure has been worked out to (hot) smoke eel fillets. Some of the important factors such as size of the fillets, brining, pre-drying, source of smoke, smoking period, final drying have been studied. Best quality of smoked product is obtained on smoking eel fillets with a mixture of coconut-husk and sag saw-dust in 1:1 proportion for 15 hours. Optimum moisture level of the final product was fixed in the range of 30 to 35% and it had a storage life of about 8 months at room temperature.
Resumo:
Following the global stringent legislations regulating the wastes generated from the drilling process of oil exploration and production activities, the management of hazardous drill cuttings has become one of the pressing needs confronting the petroleum industry. Most of the prevalent treatment techniques adopted by oil companies are extremely expensive and/or the treated product has to be landfilled without any potential end-use; thereby rendering these solutions unsustainable. The technique of stabilisation/solidification is being investigated in this research to treat drill cuttings prior to landfilling or for potential re-use in construction products. Two case studies were explored namely North Sea and Red Sea. Given the known difficulties with stabilising/solidifying oils and chlorides, this research made use of model drill cutting mixes based on typical drill cutting from the two case studies, which contained 4.2% and 10.95% average concentrations of hydrocarbons; and 2.03% and 2.13% of chlorides, by weight respectively. A number of different binders, including a range of conventional viz. Portland cement (PC) as well as less-conventional viz. zeolite, or waste binders viz. cement kiln dust (CKD), fly ash and compost were tested to assess their ability to treat the North Sea and Red Sea model drill cuttings. The dry binder content by weight was 10%, 20% and 30%. In addition, raw drill cuttings from one of the North Sea offshore rigs were stabilised/solidified using 30% PC. The characteristics of the final stabilised/solidified product were finally compared to those of thermally treated cuttings. The effectiveness of the treatment using the different binder systems was compared in the light of the aforementioned two contaminants only. A set of physical tests (unconfined compressive strength (UCS)), chemical tests (NRA leachability) and micro-structural examinations (using scanning electron microscopy (SEM), and X-ray diffraction (XRD)) were used to evaluate the relative performance of the different binder mixes in treating the drill cuttings. The results showed that the observed UCS covered a wide range of values indicating various feasible end-use scenarios for the treated cuttings within the construction industry. The teachability results showed the reduction of the model drill cuttings to a stable non-reactive hazardous waste, compliant with the UK acceptance criteria for non-hazardous landfills: (a) by most of the 30% and 20% binders for chloride concentrations, and (b) by the 20% and 30% of compost-PC and CKD-PC binders for the Red Sea cuttings. The 20% and 30% compost-PC and CKD-PC binders successfully reduced the leached oil concentration of the North Sea cuttings to inert levels. Copyright 2007, Society of Petroleum Engineers.
Resumo:
Portland cement is the most commonly and widely used binder in ground improvement soil stabilisation applications. However, many changes are now affecting the selection and application of stabilisation additives. These include the significant environmental impacts of Portland cement, increased use of industrial by-products and their variability, increased range of application of binders and the development of alternative cements and novel additives with enhanced environmental and technical performance. This paper presents results from a number of research projects on the application of a number of Portland cement-blended binders, which offer sustainability advantages over Portland cement alone, in soil stabilisation. The blend materials included ground granulated blastfurnace slag, pulverised fuel ash, cement kiln dust, zeolite and reactive magnesia and stabilised soils, ranging from sand and gravel to clay, and were assessed based on their mechanical performance and durability. The results are presented in terms of strength and durability enhancements offered by those blended binders.
Resumo:
A method is reported for smoke curing of oil sardine (Sardinella longiceps) by dry salting in the ratio of 1:6 (salt to fish), followed by smoking in the traditional smoke chamber in two stages, (1) at 45°C for 3h hand (2) at 75°C for 2h with smoke generated from coconut husk, wood shavings and saw dust in 2:2:1 proportion. The product obtained had good odour, flavour, golden yellow colour and a shelf-life of 8 weeks at room temperature (26 to 28°C)
Resumo:
A method has been standardised for the production of smoke cured mackerel by dry salting in the ratio of 1:8 salt to fish followed by smoking in a traditional smoke chamber at 70±5°C for 5h. The smoke was generated by burning moist coconut husk and saw dust. The product obtained by this method had shelf-lives of 105, 95 and 6 days in chilled storage (0 to 2°C) refrigerated storage (10±2°C) and at room temperature (29±2°C) respectively.
Resumo:
To investigate the occupational exposure levels to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs), indoor dust (n = 3) in workshops and hair samples from male workers (n = 64) were collected at two electrical and electronic equipment waste (E-waste) dismantling factories located in the LQ area in east China in July 11-13, 2006. Pre- and postworkshift urines (64 of each) were also collected from the workers to study oxidative damage to DNA using 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a biomarker. The concentrations of PCDD/Fs, PCDD/F-WHO-TEQs, PBDEs, PCBs and PCB-WHO-TEQs were (50.0 +/- 8.1) x 10(3), 724.1 +/- 249.6, (27.5 +/- 5.8) x 10(6), (1.6 +/- 0.4) x 10(9), (26.2 +/- 3.0) x 10(3) pg/g dry weight (dw) in dust, and (2.6 +/- 0.6) x 10(3), 42.4 +/- 9.3, (870.8 +/- 205.4) x 10(3), (1.6 +/- 0.2) x 10(6), 41.5 +/- 5.5 pg/g dw in hair, respectively. The homologue and congener profiles in the samples demonstrated that high concentrations of PCDD/Fs, PBDEs, and PCBs were originated from open burning of E-waste. The 8-OHdG levels were detected at 6.40 +/- 1.64 mu mol/mol creatinine in preworkshift urines. However, the levels significantly increased to 24.55 +/- 5.96 mu mol/mol creatinine in postworkshift urines (p < 0.05). Then, it is concluded that there is a high cancer risk originated from oxidative stress indicated by the elevated 8-OHdG levels in the E-waste dismantling workers exposed to high concentrations of PCDD/Fs, PBDEs, and PCBs.
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Four filamentous cyanobacteria, Microcoleus vaginatus, Phormidium tenue, Scytonema javanicum (Kutz.) and Nostoc sp., and a single-celled green alga, Desmococcus olivaceus, all isolated from Shapotou (Ningxia Hui Autonomous Region of China), were batch cultured and inoculated onto unconsolidated sand in greenhouse and field experiments. Their ability to reduce wind erosion in sands was quantified by using a wind tunnel laboratory. The major factors related to cohesion of algal crusts, such as biomass, species, species combinations, bioactivity, niche, growth phase of algae, moisture, thickness of the crusts, dust accretion (including dust content and manner of dust added) and other cryptogams (lichens, fungi and mosses) were studied. The best of the five species were M. vaginatus and P. tenue, while the best mix was a blend of 80% M. vaginatus and 5% each of P. tenue, S. javanicum, Nostoc sp. and D. olivaceus. The threshold friction velocity was significantly increased by the presence of all of the cyanobacterial species, while the threshold impact velocity was notably increased only by the filamentous species. Thick crusts were less easily eroded than thin crusts, while biomass was more effective than thickness. Dust was incorporated best into Microcoleus crust when added in small amounts over time, and appeared to increase growth of the cyanobacterium as well as strengthen the cohesion of the crust. Microbial crust cohesion was mainly attributed to algal aggregation, while lichens, fungi and mosses affected more the soil structure and physico-chemical properties.
Resumo:
本文以沈阳市城市森林为研究对象,定量研究不同树种、不同结构城市森林的滞尘能力及城市森林滞尘效益,并设计最佳的城市森林滞尘模式,为城市森林树种选择及配置模式提供科学依据。1.通过对沈阳市51种主要绿化树种滞尘能力的研究,表明不同树木滞尘力不同,决定植物滞尘能力的主要因素有,叶表面结构、叶表面积的大小,口一卜片生物量,及树木的叶面积绿量。其中计卜表面结构决定单位叶面积滞尘能力。2.单位生物量滞尘能力较强的落叶乔木有:大叶朴、紫锻、元宝械,黄金树、山里红、暴马丁香、假色械、小叶朴,糠锻,国槐;灌木或藤本类有:地锦、锦带花、重瓣黄刺玫、欧洲英迷、水蜡、金银忍冬、珍珠梅、金银花、大花水娅木。3,单位面积滞尘量最大的乔木有:辽东栎、元宝械,稠李、大叶朴、暴马丁香、山里红、枫杨、小叶朴、糠锻、紫锻。灌木有:紫丁香、水蜡、重瓣黄刺玫、东北连翘、金银忍冬、锦带花。4,通过对不同树木的单株滞尘量的测定,得出树木单株滞尘能力强的乔木有:糠锻、辽东栎、枫杨、国槐、小叶朴、元宝械、加拿大杨、大叶朴、旱柳、紫锻、蒙古栋、榆、刺槐、稠李。滞尘能力强的灌木有:紫丁香、水蜡、金银忍冬、榆计卜梅、大花水娅木、东北连翘、锦带花、红瑞木、山梅花、风箱果、重瓣黄刺玫、金银花。5.不同树种的滞尘能力与其叶表面形状和结构密切相关,通过对75种树木叶表面超微结构的观察及其与滞尘能力的对比,得出滞尘能力强的叶片表面呈凹形的并且质地较硬、较厚;叶表面有毛;叶表面细胞与细胞之间有沟谷:叶表面有凹槽;叶表面细胞上有脊状突起。滞尘能力较差的树种阶卜片表面较光滑,叶表面细胞平滑,细胞与细胞间排列整齐。6.根据树木单株滞尘量计算沈阳市城市森林总滞尘量,沈阳市城市森林主要树种的滞尘量429701.67t/年,沈阳市城市森林的滞尘量为605554.75t/年,绿化滞尘效益为4886万元/年。7.通过对滞尘后树木生理抗性的研究,结果表明不同树木滞尘后生理抗性不同,其中对粉尘污染抗性较强的树种有:榆树、榆叶梅、丁香和东北红豆杉。8,根据不同城市森林群落组成的滞尘能力及城市森林主要树种的滞尘能力研究,设计出沈阳市不同功能类型的城市森林滞尘模式。