Effect of extrusion cooking temperature on the microstructure of extruded pellets

ABSTRACT:   The microstructure of extruded pellets (EP) for fish under various extrusion cooking temperatures was studied by using a twin-shaft extruder. As the extrusion cooking temperature increased, the expansion rate increased and the bulk density of EP decreased. The liquefaction of the material started because of the increase in inner material temperature, the decrease in inner material pressure, and the decrease in main motor amperage. Thus, the microstructure of EP changed depending on the extrusion cooking conditions, that is, the extrusion cooking temperature effected greatly the liquefaction of the material. Generally, when the extrusion cooking temperature increased, the expansion rate increased, but a suitable temperature was found for a maximum expansion rate. The microstructure of the EP was caused by the liquefaction of the material and the microstructure effects on the function of EP. For example, the water holding capacity was affected by the inner bubble structure of an EP. These functions affect the character of the feed. EP produced under suitable conditions can have additional functions for feed.     

生物质燃料常温变径成型锥头研究

针对生物质常温闭式成型机的不足,本文引入了开式成型的概念,并在原有闭式成型机液压驱动设备的基础上,改进了成型腔.通过对生物质原料的力学分析,设计了开式成型的变径成型锥头.并使用小刨花、锯末等材料进行验证,探讨了对生物质常温变径成型机成型效果的影响因素,同时确定了较高成型质量时成型腔的压缩比范围.     

0#柴油和原油的水溶性成分对小球藻(Chlorella vulgaris)生长的影响

采用室内培养方法,研究了不同浓度0#柴油和原油的水溶性成分(Water accommodated fraction,WAF)对小球藻(Chlorella vulgaris)的生长影响及其差异.结果显示,低浓度的0#柴油WAF(0.30、0.10 mg/L)和原油WAF(1.17、0.58 mg/L)能够促进小球藻的生长,且0#柴油WAF的0.10 mg/L实验组和原油WAF的0.58 mg/L实验组在96h时,小球藻细胞密度显著高于对照组(P＜0.05);而高浓度的0#柴油WAF(8.10、2.70、0.90 mg/L)和原油WAF(9.36、4.68、2.34 mg/L)会抑制小球藻的生长.0#柴油和原油WAF对小球藻的96 h-EC50分别为3.34、6.54 mg/L,NOEC分别为0.30、1.71 mg/L,LOEC分别为0.90、2.34 mg/L.0#柴油WAF的毒性高于原油WAF,0#柴油和原油水溶性成分的组分差异是影响二者毒性强弱的主要因素.     

Basic handling characteristics of wood fuels: Angle of repose,friction against surfaces and tendency to bridge for different assortments

Basic handling characteristics were measured for sawdust, fuel pellets, fuel chips, hog fuel and chunkwood. The aim was to find relations between the basic handling characteristics and easily measurable fuel properties to facilitate the design of feeding systems in heating plants. The angle of repose was 25–55° and increased with the increasing ratio of particle length to thickness and with the increasing content of hooked or long particles. The angle of static friction, 10–40°, was affected more by the kind of surface than the fuel and followed the ascending order: coated plywood, urethane rubber, particle board, stainless steel, concrete and rubber belt conveyor. The tendency to bridge varied considerably and increased with greater content of hooked or long particles, a deeper fuel bed depth over the opening and a higher moisture content. The results indicate that more attention should be paid to the particle shape.     

不同饲料饲喂断奶仔猪对比试验研究

为了给断奶仔猪选择合适的饲料类型,采用2种类型的饲料对60头35日龄断奶的仔猪进行饲养试验。试验分为2组,即颗粒饲料组和粉状饲料组,每组三个重复,经30 d的饲养试验,结果表明：颗粒饲料组仔猪体质量每日增加数、日头均耗料量明显高于粉状饲料组（P〈0.05）,且颗粒饲料组的经济效益要高于粉状饲料组,而饲料转化效率没有明显差异（P〉0.05）,说明颗粒饲料比粉状饲料更适合饲喂断奶仔猪.     

Fuel consumption as indicator of the economics in mechanization

After a brief discussion of production functions as models for input/output relations in forest work operations, studies of the cost of machine use are reviewed. It is suggested that the fuel consumption of a forest machine can be used as a parameter for assessing the true, total cost of using a machine, exclusively the wage of the operator. Fuel then is not only an input but also represents all other cost items such as capital (depreciation, interest), repairs and maintenance. This has the advantage that all machines in a system can be aggregated and their costs assessed by an easily quantified parameter. Capital (in the form of machines) in production functions, through which the optimum mix of labour and machines for minimizing the cost per unit of production is determined, can be substituted by fuel. It is also suggested that fuel consumption can be used in management as an aggregate indicator in planning, control, remuneration of work and forecasting.     

Treatment of cow-waste slurry by a microbial fuel cell and the properties of the treated slurry as a liquid manure

Resource recycling and the proper treatment of animal waste to reduce its environmental impact are currently important issues for the livestock industry. A microbial fuel cell (MFC), a new type of bioreactor, is expected to play roles in both waste‐water purification and energy recovery. However, the generation of electricity from cow waste has not yet been examined. In this study, using an MFC, we examined the possibility of generating electricity from dairy‐cow waste slurry, and analyzed the properties of the treated slurry as liquid manure for resource recycling. The MFC treatment of the slurry generated electricity in a dose‐dependent manner, and the maximum power output by the MFC from a 1 g of chemical oxygen demand/L slurry was 0.34 mW/m². After the MFC treatment, 84% of the biological oxygen demand in the slurry was removed and three essential fertilizer elements (nitrogen, phosphorus, and potassium) were retained at 84, 70, and 91% levels, respectively. The amount of ammonia nitrogen in the slurry, as an element of fast‐release fertilizer, was increased by 1.9‐fold. Although the treated slurry displayed properties that made it preferable as liquid manure, further studies to improve the electrical power output by the MFC are required for practical use.     

Effect of Freezing Snow Disaster on Forest Fuel and Fire Behavior in Southern China

After freezing snow disaster,stands of Pinus massoniana,Cunninghamia lanceolata. Liquidambar formosana,Cinnamomum camphora and Phyllostachys pubescens and new burned areas in Hunan Province were surveyed by setting field plots.Moisture content and fuel load were measured by sampling and fire behavior(such as rate of fire spread) was calculated.The results showed that fuel load got doubled instantly,fuel thickness enhanced,fuel continuity swelled and water content of fuel decreased as shrubs and herbs die...     

YL2208CW型农用运输车主传动比的模糊优化

作者在建立Ｙ１２２０８ＣＷ型农用运输车动力性与燃油经济性模拟计算方法的基础上，应用模糊数学方法优化农用运输车的主传动器速比，获得了最佳燃油经济性。