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This paper concerns the kinetic approach to measuring glucose mineralization by planktonic bacteria in Whitson Lake, a moderately acidic lake. For all three samplings, plots of the amount of glucose mineralized vs time of incubation were linear at both high and low concentrations of added glucose. When sample water buffered around the in situ pH was used in these time studies, linear relationships were again evident, but there was a reduction in the rates of glucose mineralization activity. Nevertheless, the kinetic approach usually failed to generate the Michaelis—Menten response at the necessary level of statistical significance to justify calculations of turnover times and Vmax values. And, buffering the pH around the in situ pH did not insure that the Michaelis—Menten response would be obtained.These observations are discussed in the light of our earlier observations involving an extremely acid-stressed lake. 相似文献
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Sivakumar Palanivelu Wim Van PaepegemJoris Degrieck Bruno ReymenJean-Marie Ndambi John VantommeDimitrios Kakogiannis Jan WastielsDanny Van Hemelrijck 《Engineering Structures》2011,33(6):1966-1987
This article deals with the experimental and numerical blast study on a single empty recyclable metal beverage can. The idea is to make a macro-foam (sacrificial cladding structure) out of these cans to protect the main load bearing members of civil engineering structures from the air blast load. Close-range free air blast tests have been conducted to understand the crushing behaviour and the energy absorption of a single empty beverage can in detail. To conduct such an air blast test a special small-scale test set-up was designed and manufactured. The effect of skin plate surface area and its nature on the blast parameters is studied. Furthermore, the effect of inertia of the skin plate on the crushing performance of the beverage can is evaluated. Tests have been conducted with different plates (made of aluminium and sandwich composite materials) with different masses which represent the skin plate of the proposed sacrificial structure. The measured blast parameters from the experimental tests were compared with ConWep predicted data. Furthermore, the influence of the finite surface area of the skin plate on the clearing of the reflected pressure waves was also studied. The deformation behaviour and the corresponding energy absorption of empty beverage cans were captured. During the experimental blast tests it was observed that a part of the total reflected impulse (∼30%) was lost before it transfers to the non-sacrificial structure. Hence, in order to investigate this phenomenon Eulerian-Lagrangian coupled analyses were conducted using Hydrocodes. The results from these analyses showed that the diffraction and ground reflected pressure wave caused the loss in impulse. The results from the numerical studies have been compared and validated with the experimental results. 相似文献
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鲜榨果蔬汁、现磨咖啡、新式茶饮等现制饮料深受消费者的喜爱,然而由于原材料品质把控不严、加工过程操作不规范等,导致现制饮料存在微生物污染的风险。本文综述了我国现制饮料中微生物污染状况及行业监管现状,分析了现制饮料在加工过程中微生物污染的原因,找出关键控制点并提出干预措施,为促进我国现制饮料行业的健康发展提出了建议。 相似文献
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Public willingness to pay a premium for uni‐material beverage container in Korea: a contingent valuation study 下载免费PDF全文
The use of uni‐materials can reduce the total waste generation by a high recycling rate. This study assesses the public's willingness to pay (WTP) a premium for the uni‐material beverage container (UBC) in Korea using a specific case of bottled mineral water in polyethylene terephthalate (PET). For this purpose, a contingent valuation (CV) survey of 1000 consumers was conducted to derive the additional WTP for the mineral water in UBC instead of that in non‐UBC. Given that the average price of the mineral water (500 mL) in non‐UBC was KRW 1000 (USD 0.88), the mean additional WTP a premium for that in UBC was estimated to be KRW 107 (USD 0.09). This value amounts to 10.7% of price of the mineral water in non‐UBC and can be interpreted as the public value of the UBC. The consumers in Korea are ready to pay a significant premium for UBCs. 相似文献
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流砂过滤器/超滤工艺用于饮料厂中水回用工程 总被引:2,自引:0,他引:2
采用流砂过滤器/超滤工艺处理饮料厂污染程度低的部分生产废水,并进行中水回用.其中砂滤出水符合《城市污水再生利用城市杂用水水质》(GB/T 18920-2002),可回用于厂区绿化、景观、洗车、冲厕等非生产用水;超滤出水接近自来水水质标准,可回用于生产用水.该项目经过近一年的运行,系统稳定,可节约市政自来水量为1 880 m3/d,经济和环境效益显著. 相似文献
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在2 mol/L NaCl酸性溶液中,研究少量Sc对铸态Al-3Cu-1Li合金腐蚀行为的影响。通过XRD对铸态Al-3Cu-1Li-xSc(质量分数)合金进行相分析,用FE-SEM/EDS和TEM观察了Al-3Cu-1Li合金和Al-3Cu-1Li-0.5Sc合金的显微组织;采用极化曲线、电化学阻抗谱(EIS)、电化学噪声(EN)和浸泡法对合金的腐蚀行为进行了研究,并探讨腐蚀机制。结果表明:含Sc的Al-3Cu-1Li合金晶内富Cu球形相减少,晶界析出W相。随Sc含量的增加,合金腐蚀反应的活化能降低,阴极析氢速率增加,自腐蚀电流密度增加,合金的耐蚀性降低。添加Sc后,合金在空气中形成的表面膜保护作用减弱至消失,使含Sc合金的阻抗谱低频感抗弧逐渐消失。在EN测量期间,不含Sc和含0.1%Sc的合金表面处于“膜破裂-再钝化”状态;含0.3%Sc和0.5%Sc的合金发生严重的局部腐蚀(晶间腐蚀),且与W相有关。 相似文献
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建立了工作场所中硅胶管吸附空气中乙酸用丙酮解吸后酸性毛细管柱气相色谱( FID)测定乙酸的方法。通过测试该方法的精密度、准确度、解吸效率,结果令人满意,结果表明本方法适用于工作场所中空气中乙酸的测定。 相似文献