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401.
Extruded Cornstarch-Glycerol-Polyvinyl Alcohol Blends: Mechanical Properties, Morphology, and Biodegradability 总被引:3,自引:0,他引:3
Lijun Mao Syed Imam Sherald Gordon Patrizia Cinelli Emo Chiellini 《Journal of Polymers and the Environment》2000,8(4):205-211
Elongation properties of extruded cornstarch were improved by blending with glycerol. Further blending of starch-glycerol with polyvinyl alcohol (PVOH) resulted in significant improvements in both tensile strength (TS) and elongation at break. Samples of starch-glycerol without PVOH equilibrated at 50% relative humidity had a TS of 1.8 MPa and elongation of 113%, whereas those containing PVOH had a TS and elongation of 4 MPa and 150%, respectively. Dynamic mechanical analysis (DMA) of starch-glycerol-PVOH blends showed that decreases in glass transition temperatures (T
g values) were proportional to glycerol content. Scanning electron microscopy (SEM) of fractured surfaces revealed numerous cracks in starch-glycerol (80:20) samples. Cracks were absent in starch-glycerol (70:30) samples. In both blends, many starch granules were exposed at the surface. No exposed starch granules were visible in blends with added PVOH. Starch-glycerol samples incubated in compost lost up to 70% of their dry weight within 22 days. Addition of PVOH lowered both the rate and extent of biodegradation. 相似文献
402.
403.
微电解预处理提高酒精废水可生化性的试验研究 总被引:13,自引:2,他引:11
经厌氧生物处理后的酒精废水COD浓度为 650 0mg/L ,B/C比 0 .33 ,可生化性较低。为了改善该废水的可生化性 ,提高后续好氧处理效果 ,将酒精废水消化液进行铁屑—活性炭微电解预处理。结果表明 ,该废水COD去除率达 50 %左右 ,其B/C比提高为 0 .55左右 ,提升幅度高达 67% ,为后续好氧处理创造了有利条 相似文献
404.
405.
灰色系统理论在城市交通噪声预测和绝对关联度分析中的应用 总被引:18,自引:0,他引:18
运用灰色系统理论的动态建模方法,根据最近7年的时间序列数据,建立了城市道路交通噪声的灰色预测模型。本模型经检验为一极模型,进行中、短期预测精度高,残差仅±0.7%。对某市未来几年交通噪声变化的趋势进行了预测。同时对影响城市交通噪声变化的8个相关因素进行了绝对关联度分析,确定了城市人口、车流量及机动车数量变化为影响交通噪声变化的优势因素。为交通噪声污染防治提供了科学依据。 相似文献
406.
废水中乙醛的化学发光法测定 总被引:3,自引:0,他引:3
乙醛发光分析法的检出限为8×10~(-11)g/ml,线性范围为5×10~(-10)g/ml-1×10~(-6)g/ml.对近30种常见无机物和有机物对乙醛测定的影响进行了试验,表明该方法具有良好的选择性.用于有机化工和印染废水中乙醛的测定,其回收率为94%~100%,变异系数为1.6%—6.4%。 相似文献
407.
高效液相色谱-电感耦合等离子体质谱联用测水中有机汞 总被引:1,自引:1,他引:0
建立了高效液相色谱-电感耦合等离子体质谱联用技术(HPLC-ICP-MS)测定水样中甲基汞、乙基汞、苯基汞等3种有机汞的分析方法。采用醋酸铵-L-半胱氨酸缓冲盐及甲醇体系组成的流动相按一定比例进行梯度洗脱,Agilent Zorbax Plus C18柱分离,经前处理的水样在液相色谱中分离后,进入电感耦合等离子体质谱检测其甲基汞、乙基汞、苯基汞的浓度。3种有机汞化合物均在0.50~50.0μg/L范围内呈良好的线性关系,线性相关系数均大于0.999 5。仪器检出限为0.09~0.12μg/L,方法检出限为0.4×10-6~0.6×10-6mg/L,3种有机汞样品加标的RSD均小于11.3%,2个水平的加标回收率为74.4%~83.2%。 相似文献
408.
Identification of the leakage of hazardous gases plays an important role in the environment protection, human health and safety of industry production. However, lots of current optimization algorithms, such as particle swarm optimization (PSO) and Grey Wolf Optimizer (GWO), suffer from poor global optimization capability and estimation accuracy. In this work, a hybrid differential evolutionary and GWO (DE-GWO) algorithm is proposed. Tested by simulation cases and Prairie Grass emission experimental data, DE-GWO shows higher estimation accuracy than GWO. Compared with the other four optimization algorithms, DE-GWO exhibits finer robust stability under different population sizes, fewer iterations, as well as higher estimation accuracy with fewer search agents. Importantly, simulation results demonstrate that DE-GWO is more suitable to apply in the scene with a small number of sensors. Therefore, the proposed in this paper outperforms other optimization algorithms for the gas emission inverse problem. DE-GWO can provide reliable estimation towards gas emission identification and positioning, which shows huge potential as the data analysis module of real-time monitoring and early warning system. 相似文献
409.
Simplified creation of polyester fabric supported Fe-based MOFs by an industrialized dyeing process: Conditions optimization, photocatalytics activity and polyvinyl alcohol removal 下载免费PDF全文
MIL-53(Fe) was successfully prepared and deposited on the surface carboxylated polyester (PET) fiber by an optimized conventional solvothermal or industrialized high temperature pressure exhaustion (HTPE) process to develop a PET fiber supported MIL-53(Fe) photocatalyst ([email protected]) for the degradation of polyvinyl alcohol (PVA) in water under light emitting diode (LED) visible irradiation. On the basis of several characterizations, [email protected] was tested for the photocalytic ability and degradation mechanism. It was found that temperature elevation significantly enhanced the formation and deposition of MIL-53(Fe) with better photocatalytic activity. However, higher temperature than 130°C was not in favor of its photocatalytic activity. Increasing the number of surface carboxyl groups of the modified PET fiber could cause a liner improvement in MIL-53(Fe) loading content and photocatalytic ability. High visible irradiation intensity also dramatically increased photocatalytic ability and PVA degradation efficiency of [email protected] Na2S2O8 was used to replace H2O2 as electron acceptor for further promoting PVA degradation in this system. [email protected] prepared by HTPE process showed higher MIL-53(Fe) loading content and slightly lower PVA degradation efficiency than that prepared by solvothermal process at the same conditions. These findings provided a practical strategy for the large-scale production of the supported MIL-53(Fe) as a photocatalyst in the future. 相似文献
410.
对拟负刚度阻尼减振结构的动力特性与减振效果进行了研究。首先,证明了采用拟负刚度控制方法时,结构响应与外荷载之间满足齐次性;其次,对拟负刚度阻尼减振结构的加速度放大系数和位移放大系数进行了研究,并与粘滞阻尼减振结构的加速度放大系数和位移放大系数进行了比较;最后,对地震荷载作用下拟负刚度阻尼减振结构的减振效果进行了分析。研究结果表明:当外荷载与结构的频率比大于1或结构的周期较长时,拟负刚度控制对结构绝对加速度的控制效果要好于粘滞阻尼减振结构的控制效果,对结构位移的控制效果要差于粘滞阻尼减振结构的控制效果。 相似文献