绿豆饮料添加稳定剂的响应面法优化

【目的】以绿豆为原料,添加不同的稳定剂优化绿豆饮料的稳定性。【方法】以绿豆饮料离心沉淀率为指标,在调查羧甲基纤维素钠(CMC-Na)、三聚磷酸钠(STPP)、六偏磷酸钠(SHMP)3个单体稳定剂影响绿豆饮料稳定性单因素试验结果的基础上,采用响应面分析确定最佳稳定剂配比。【结果】结果表明,当复合稳定剂CMC-Na、STPP和SHMP的添加量分别为0.02%、0.10%、0.06%时,绿豆饮料的离心沉淀率最小值为9.19%。【结论】降低沉淀率,部分解决绿豆饮料沉淀问题,为绿豆饮料生产提供参考。     

Excess River Sedimentation at Bridges in the Raya Graben (Northern Ethiopia)

This study investigates the temporal variability and effects of bio‐climatic factors and bridges on local hydro‐geomorphic conditions that cause excess sedimentation and flood hazard in ephemeral rivers of the Raya graben (northern Ethiopia). Normalized difference vegetation index (NDVI) was analyzed using Landsat imageries of 1972, 1986, 2000, 2005, 2010, and 2014. Daily rainfall data of three meteorological stations were considered to analyze the temporal trends and return time intervals of rainfall intensity in 24 h. Stream‐bed gradient and bed material grain size were measured in 20 river reaches. Results show that the maximum NDVI values were recorded in the time interval from 2000 to 2014. Nevertheless, during this decade, the study bridges experienced the largest excess sedimentation, in some bridges up to 1·6 m. Different factors to account for it are discussed as no evidence of rainfall pattern, accountable for an increase in sediment delivery from the headwaters, is found. The field data show that channel narrowing at bridges is the main cause of thick upstream sedimentation and of increasing frequency of overbank flows during the last 15 years. A simple hydraulic approach is presented to explain the variability of sediment deposition at bridges and change in bed material grain size between the main stem and the reach right upstream of the bridge. Copyright © 2016 John Wiley & Sons, Ltd.     

Gully Head Retreat in the Sub‐Humid Ethiopian Highlands: The Ene‐Chilala Catchment

In the northern highlands of Ethiopia, gully erosion is severe. Despite many efforts to implement gully prevention measures, controlling gully erosion remains a challenge. The objective is to better understand the regional gully erosion processes and to prevent gully head retreat. The study was conducted in the Ene‐Chilala catchment in the sub‐humid headwaters of the Birr River located southwest of Bahir Dar, Ethiopia. Twelve gully heads were monitored during the 2014 and 2015 rainy monsoon phase. We measured gully head morphology and retreat length, soil shear strength, ground water table levels, and catchment physical characteristics. Two active gully head cuts were treated in 2014 and an additional three head cuts in 2015 by regrading their slope to 45° and covering them with stone riprap. These treatments halted the gully head advance. The untreated gullies were actively eroding due to groundwater at shallow depths. The largest head retreat was 22.5 m, of which about half occurred in August of the first year when the surrounding soil was fully saturated. Lowering both the water table and protecting the gully heads can play a key role in reducing gully expansion and soil loss due to gully erosion in the Ethiopian highlands. Copyright © 2016 John Wiley & Sons, Ltd.     

Sediment Yield Deduction from Check–dams Deposition in the Weathered Sandstone Watershed on the North Loess Plateau,China

As the basic unit of erosion and sediment yield, it was critical to determine the amount of soil erosion and sediment yield in the small watersheds for sustaining a reasonable water resource and sediment regulation system. In this study, we determined the sediment yield from the dams‐controlled watershed on the North Loess Plateau. Three check dams in the watershed were investigated by drilling ten‐hole sedimentation cores. The corresponding flood couplets were dated according to thickness of deposition layers, distribution of sediment particle size and historical erosive rainfall events. On the basis of the check dams capacity curve, the soil bulk density and the thickness of couplets, the deposit mass of check dams, and then the sediment yield of watershed at different temporal and spatial scale were deducted. In total of the 33, 60 and 55 couplets were corresponded to individual flood events in the dam MH1# from 1976 to 1984, the dam MH2# from 1985 to 2007, and the dam MH4# from 1981 to 2009, respectively. The specific sediment yield for flood events was 1,188.5–11,527.9 Mg km⁻², 1,278.6–17,136.7 Mg km⁻², and 3,395.9–33,698.5 Mg km⁻², and the annual average sediment yield was 10,728.6 Mg (km² · a)⁻¹, 12,662.9 Mg (km² · a)⁻¹, and 16,753.3 Mg (km² · a)⁻¹ in dam MH1#, MH2# and MH4# controlled watershed, respectively. The sediment yields were inversely proportional to the dams – controlled areas. For the whole watershed, the annual average sediment yield was 14,011.1 Mg (km² · a)⁻¹ from 1976 to 2009. There were large amounts of sediments (42.3–50.5%) were intercepted gradually along the way from small watersheds to the river channel. And the minimum rainfall for sediment deposited in the dams was greater than 20 mm in this watershed. The results of this study suggested that the sediments retained behind check dams were helpful to quantifying the amount of erosion sediment yield and understanding the soil erosion evolution in the small and ungauged watersheds. Copyright © 2016 John Wiley & Sons, Ltd.     

RESEARCH ON SEDIMENTATION TECHNOLOGY OF CHEVRON-SHAPED TUBE

Research results show that chevron-shaped tube has adva-ntages of better hydraulic condition needed for sedimentation and adapta-bility for treatment of raw water turbidity.This paper points out the wayto select the construction parameters of chevron-shaped tube.The contrastresearch between chevron-shaped tube and honeycomb-shaped tube has beendone.The formula of hydraulic characteristic parameter of chevron-shapedtube is given.This formula sets out a theoretic base for practical applicationof chevron-shaped tube.     

Sedimentation law research and transportationfeasibility study of backfilling slurry

Through the analysis of movement forms of backfilling slurry in the pipeline self-flowing transportation system and the sedimentation law of backfilling aggregate granule, it is known that the transportation stability of backfilling slurry is related to transportation speed and the length of horizontal pipeline. Combined with the characteristics of gangue paste-like slurry in Suncun Mine, the pipeline transport process of slurry is simulated by Fluent, which is a well-known fluid analysis software, and also the self-flowing transportation feasibility of paste-like slurry with gangue as main backfilling aggregate is researched in theory. The research shows that the self-flowing pressure can overcome the resistance loss in the way of the transmission pipeline. When the horizontal pipe transmission speed is 3.82 m/s, the vertical pulsating velocity component of slurry (Sv) can reach 38.3 cm/s and the interfering sedimentation speed of gangue (Vgg) is just 0.99 cm/s, it can know that Sv > Vgg. Therefore, paste-like slurry can arrive at the mined-area by self-flowing transportation.     

非粘性均匀沙群体沉降运动沉速公式的研究

从相对运动的观点出发,将非粘性均匀泥沙群体沉降运动概化为上升水流在悬浮颗粒层内的运动,通过量纲分析和动平衡状态受力分析,建立了泥沙群体沉降运动中阻力系数和雷诺数的表达式,并分别建立了层流区和紊流区均匀沙群体沉速的理论公式,其结构形式与目前常用的经验公式较为一致。应用实测资料对公式进行验证的结果表明,应用该理论公式的计算值与实测值吻合程度较好。同时通过分析讨论,提出了非均匀沙群体沉降速度问题的解决途径。     

小型污水处理厂工艺初步诊断方法及改进研究

我国小型污水处理厂在设备、工艺和运行等方面,都普遍存在一些有待于进一步改进的共性技术.本文对包头市的一个小型污水处理厂的污水处理工艺进行了初步诊断,结果显示其旋流沉砂池水力负荷较大、初沉池和二沉池沉降效果较差、生物池污泥浓度低和泥龄短是该厂处理工艺存在的主要问题,同时由于进水污染物浓度较高,也导致了出水氨氮和总磷超标率较高.在此基础上,提出了开展进一步的系统化工艺诊断、优化溶氧浓度和污泥浓度、利用混凝加药试验寻求最佳组合方式的改进思路,以提高污染物去除效果,降低运行成本.并建立污水厂信息管理系统,实现数字化管理,为提高运行管理水平提供了技术手段和理论依据.     

新型异向流沉沙池泥沙沉降特性试验与机理分析

为了探明二级泥沙处理设施--新型异向流沉沙池的泥沙沉降特性及其沉沙机理,该研究开展了不同流量和不同含沙浓度的系列试验,并对泥沙运动过程进行了力学分析,建立并求解了新型异向流沉沙池双向倾斜薄板上泥沙运动的一阶非线性微分方程。研究结果表明,对于中值粒径为0.021 mm的细颗粒泥沙的含沙水流,长96 cm、宽10 cm、高110 cm的新型异向流沉沙池对流量为45～360 L/h的泥沙截除率为40%～88.53%,约为相同体积的底板倾斜和底板水平的条形沉沙池的1.2～2倍;单位时间沉降至集沙箱的泥沙量是底板倾斜条形沉沙池的1.3～2.3倍;不同时刻双向倾斜薄板上的泥沙运动速度和加速度均大于单向倾斜斜板,倾角为锐角时,角度越大,速度越大。工程设计时,若地形高差满足要求,双向倾斜薄板的倾角（<90°）越大越有利于提高沉降效率,若高差不满足,倾角应不小于泥沙休止角。研究结果可为新型异向流沉沙池结构优化及应用提供参考。     

微量沉淀值和麦谷蛋白亚基组成对面包烘烤品质的效应

为快速高效地改良中国小麦品种的面包烘烤品质,将72份冬小麦品种(系)于2000～2001年度分别种植于河南郑州和山东济南,分析了它们的蛋白质品质和面包烘烤品质,评价了蛋白质含量、微量沉淀值及高、低分子量麦谷蛋白亚基组成对面包烘烤品质的作用.结果表明,总体上中国冬小麦品种的蛋白质含量和微量沉淀值中等偏高,面包烘烤品质则较差,品种间差别较大.高、低分子量麦谷蛋白亚基的等位变异与面包烘烤品质密切相关,Glu-Dl位点具有5 10亚基和Glu-B3位点具有h亚基的品种,其面包各烘烤品质参数均显著优于具有其他亚基的品种,而Glu-B3j亚基(即1B/1R易位)对微量沉淀值、比沉淀值和面包体积、颈高、外观、质地、结构、色泽、评分等品质参数均具有较大的负向作用.沉淀值对非1B/1R易位系面包体积和评分的作用远大于蛋白质含量的贡献,而单位蛋白质含量的沉淀值即比沉淀值对1B/1R易位系的面包体积和评分更重要.在育种中应针对非1B/1R易位系和1B/1R易位系采用不同的品质改良策略,对非1B/1R易位系可考虑通过提高沉淀值,对1B/1R易位系则应考虑通过提高比沉淀值来改良面包烘烤品质.