影响农机购买的因素

购买农机的用户可分为集团购买和个人购买.集团购买农机时主要考虑的因素为产品的技术参数、性能特点、售后服务、价格等.农民个人购买农机除了考虑以上的因素外,他们还把品牌的社会影响力以及周围农机户的口碑也作为重要的因素.尽管有人认为集团购买更为理性,个人购买时感性的成分更多一些,但实际上所有的购买行为都会受到决策者心理因素的影响.     

分解MP3：一种节俭的收听装置技术

在我买了一个激光打印机碳粉盒之后,一张“赠送价值75美元物品”优惠券还给我家带来了一台O D-128MP3,也就是人们熟知的MP3-818便携式数字音频播放器。这个价格在我听来如同音乐,特别是考虑到OfficeDe-pot对这种播放器的正常标价是69.99美元。它的特性也不算太平庸:对MP3和WMA(     

领会无成本之路

之前,EDN分析了一个削价至20美元(原价为50美元)的USB音频外设。这次我们继续对ABS打折后的NW-203-RT 802．11g与四端口开关式路由器进行财务分析。在这个淡紫色塑料壳内都有些什么东西?卖20美元ABS还赚钱吗?     

Mathematical Models of Flavor Release from Liquid Emulsions

The penetration theory of interfacial mass transfer was used to model flavor release from liquid emulsions. The model was used to predict the rates of release and partitioning properties of two volatiles, one hydrophilic (diacetyl) and the other hydrophobic (heptan-2-one), as a function of the oil volume fraction. In general the initial rates of release were faster for emulsions of lower oil content, whereas the equilibrium concentrations depended on the nature of the flavor compound and the volume fraction of oil in the emulsion. Experimental in vitro results suggested that the rate limiting step for flavor release was the resistance to mass transport across the emulsion-gas interface.     

AN EXPERIMENTAL STUDY OF POLYMER DIFFUSION IN CONCENTRATED SOLUTION: IMPLICATIONS FOR DIFFUSION IN POLYMERIZATION

The Trommsdorf or gel effect in free radical polymerization is due to the fact that the termination reaction becomes strongly diffusion controlled above a critical concentration associated with the onset of molecular entanglements. Therefore, an understanding of polymer self-diffusion in entangled systems becomes essential to understanding the Trommsdorf effect. Our group has previously proposed a molecular model for the gel effect which uses a specific theory for polymer diffusion (reptution). The present work represents an experimental attack on the same problem Experimental studies of polymer self-diffusion in entangled systems are scarce. Quasielastic light scattering from ternary systems composed of solvent(l)-polymer(2)-polymer(3), in which species (3) is isorefractive to the solvent (i.e. 0n/0c ₃ = 0), offers an attractive way to study the tracer diffusion coefficient of species (2) in a binary mixture of composition c ₃. In regimes of low momentum transfer (qR _G < 1,) where q is the scattered wave vector and R _G is the polymer radius of gyration, we have shown that the correlation function of the scattered electric field should decay with a single exponential decay time, given by (D₂₂ q ²)^?1 where D ₂₂(c ₂, c ₃) is the main ternary diffusion coefficient of component (2). Extrapolation to zero concentration of 2) at fixed concentration of (3) yields the tracer diffusion coefficient of (2) in the binary mixture of (1) and (3). The systems toluene(l)-polystyrene(2)-polymethylmethacrylate(3) (0n/0c ₃ ≈ 0.007 at 25°C) and toluene(l)-polystyrene(2)-polyvinylmethylether (3) (0n/0c ₃ ≈ 0.012 at 60°C) very nearly satisfy the above criteria. In both systems, we have found that the tracer diffusion coefficient of the polystyrene decreases with increasing concentration of the isorefractive polymer. Further studies have focused upon the dependence of the tracer diffusion coefficient upon polystyrene molecular weight, and upon the effect of incomplete index matching.     

Sensory Detection and Population Thresholds for Sodium Tripolyphosphate in Cooked Ground Turkey Patties

Sodium tripolyphosphate (STP) at levels of 0.1, 0.2, 0.3, 0.4, and 0.5% by weight was added to ground turkey meat to determine if a flavor difference could be detected when STP was present. Detection thresholds for STP in ground turkey meat were determined for 30 female respondents. Two population thresholds were determined using information from the detection thresholds. Two-thirds of the respondents detected a difference between samples with no STP and those with 0.5% STP or less. STP added at less than 0.3% was undetected by more than 50% of the tested population.     

Microbiological Evaluation of Alaska Shore-based Surimi Production

Two shore-based surimi plants in Alaska were investigated to determine microbial conditions of Alaska pollock flesh during processing. Median aerobic plate count (APC) was 2.0 × 10³/g after mincing, 2.3 × 10³/g after washing/screening, 4.2 × 10⁴/g after refining and 1.6 × 10⁴/g after dewatering. Reprocessing, needed for nonanalog grade surimi, resulted in APC of 1.2 × 10⁵/g after a second refining and 3.0 × 10⁵/g after a second dewatering. The APC for analog grade surimi was 5.5 × 10⁴/g and 2.0 × 10⁶/g for nonanalog grade surimi. Highest total coliform most probable number (MPN) of > 1100/g was determined from a nonanalog grade surimi sample and from a mince that had been refined twice. Highest Escherichia coli MPN of 460/g was determined from two minces.     

WASTE FLOW ALLOCATION PLANNING THROUGH A GREY FUZZY QUADRATIC PROGRAMMING APPROACH

This paper proposes a grey fuzzy quadratic programming (GFQP) approach as a means for optimization analysis under uncertainty. The method combines the ideas of grey fuzzy linear programming (GFLP) and fuzzy quadratic programming (FQP) within a general optimization famework. It improves upon the previous GFLP method by using n grey control variables, ® (A,j (i = 1,2,..., n), for n constraints instead of one ® (X) for n constraints in order to incorporate the independent properties of the stipulation uncertainties; it also improves upon the FQP method by further introducing grey numbers for coefficients in A and C to effectively reflect the lefthand side uncertainties. Compared with the GFLP method, the GFQP approach is helpful for better satisfying model objective/constraints and providing grey solutions with higher system certainty and lower system cost; compared with the FQP method, more information of the independent uncertain features of not only the stipulations but also the lefthand side coefficients are effectively reflected in the GFQP method.

The GFQP modelling approach is applied to a hypothetical case study of waste flow allocation planning under uncertainty, with the input model stipulations fluctuating within wide intervals and having independent uncertain characteristics. The results indicated that reasonable solutions have been generated. Comparisons between the GFQP and FQP/GFLP solutions are also provided, which demonstrate that the GFQP method could better reflect system uncertainties and provide more realistic and applicable solutions with lower system uncertainties and higher system benefits.     

A NEW LOOK AT THE OPTIMUM DIMENSIONS OF CONVECTIVE SPINES

The optimum dimensions of spines of various profiles are reexamined by taking into account the profile curvature effects. Simple working formulas for the optimum dimensions are proposed. When the ratio of spine width to length, δ₀/b₀, is set equal to zero, the present results are reduced to the earlier findings which are obtained on the basis of employing the length-of-arc assumption.