粮堆声传播参数测量系统的研究

通过对颗粒介质的特征参数与堆积参数的测量,建立粮堆中声传播参数的测量系统,证实了粮堆中波动参数与粮堆密度、容重等堆积参数和水分、粒重等粮食的籽粒参数有密切关系,得到了小麦中声传播参数与小麦及其堆积参数与粮堆密度的回归模型。     

纺粘牵伸器牵伸机理研究(Ⅰ)

本文对NWT狭缝式牵伸器、STP和摩登管式牵伸器、莱芬文丘里式牵伸器进行了气流参数试算 ,研究了气体初始参数、牵伸器结构几何参数、纺丝参数等对牵伸器气流参数和单丝受力的影响 ,设计出一种整体狭缝式牵伸器 ,讨论了各种参数对牵伸器性能的影响 ,为建立各种参数与牵伸器气流参数之间的数学模型和优化设计牵伸器提供了理论依据。     

鞋博士信箱

Q请介绍运动学参数。A运动学参数有时间参数、空间参数、时空参数。1.时间参数(1)时刻:是人体位置的时间量度,是时间上的一个点。(2)时间:是运动结束时刻与运动开始时刻之差值,过程量。     

浅述6×25 Fi+IWR钢丝绳生产工艺

介绍6×25Fi+IWR钢丝绳结构参数的确定,工艺参数的选择,及按此结构参数和工艺参数生产的钢丝绳质量状况。     

基于Creo二次开发的外啮合圆柱齿轮优化设计

针对外啮合圆柱齿轮设计过程中繁琐的参数计算优化,在Creo上对其进行参数化建模与二次开发.以Creo的参数关系驱动的参数化技术为支撑,创建外啮合圆柱齿轮参数化模型,实现了模型的参数驱动与控制.通过VS2012、Pro/ToolKit建立可视化开发环境,开发了针对齿轮的顶切根切、滑动率、干涉检查等参数化交互设计界面.     

成熟度对渝甜糯蒸煮产品和烘烤产品品质的影响

对不同成熟度渝甜糯蒸煮产品和烘烤产品的品质进行质构分析和感官评定,并深入分析质构参数之间及质构参数与感官评定参数之间的相关性。结果表明,蒸煮产品质构参数与感官评定参数之间具有良好的相关性;烘烤产品质构参数与感官评定参数之间也具有良好的相关性;授粉后20d采收的渝甜糯适合生产蒸煮食品;授粉后30d采收的渝甜糯适合生产烘烤食品。     

螺栓头下圆角强化参数的理论计算模型研究

螺栓头下圆角强化是依靠滚压形成塑性形变使表面产生残余压应力实现强化效果,强化效果的关键是滚压参数的确定。参数确定常以正交试验法或仿真加试验验证的方法进行参数摸索验证,存在参数验证周期长、试验成本高及效率低下的问题。针对此问题,该文通过构建圆角理论模型并进行接触力学分析,给出强化参数的计算方法,再通过试验验证,提高强化参数确定的效率。     

用色度仪和质构仪对高蛋白挂面色泽和质地的研究

用色度仪和质构仪分别测定添加不同比例脱脂大豆粉挂面的色泽和质构参数,分析了挂面的色泽参数、质构参数与面条感官评分之间的相关关系。结果显示,感官评价指标中的色泽得分与色度仪的亮度参数L!高度正相关,质构参数与感官评价指标无显著相关。分析认为,用色度仪的亮度参数L!取代感官评分中的色泽指标是可行的,质构参数中的硬度和拉伸距离与口感指标相关度较高,有重要的参考价值。      

基于Rhino的服装原型参数化制版方法

为提高服装原型制版与服装私人化定制效率,解决制版师学习制作参数化制版系统高门槛的问题,以东华原型版为模型基础,采用参数化思路建立几何约束关系,选取人体身高与胸围为主要参数,肩宽、肩斜等9个细节尺寸为修正参数,结合上述参数采用Rhino软件构建服装原型参数化制版系统,分析修正参数对板片的影响。最后重构服装板片,实现二维衣片转三维模型,并在CLO3D软件中对身高170 cm,胸围80 cm的原型版进行面料应力分析。结果显示：基于Rhino的图形化服装原型参数化制版方法相对于语言类编程更为直观易懂,修正参数的优化使得板片修改更为简便,简化了参数化制版方法,降低了学习编程语言的门槛,可为后续服装参数化制版系统的制作与方法的推广提供参考。     

数据误差对飞机气动参数评估的影响研究

飞机在设计过程中,为了获得飞机真实准确的气动参数,通过对飞机试飞数据进行参数评估获取精确气动参数是一种有效的手段。但由于试验测试仪器的因素,试飞数据的误差影响了参数评估的精度。文章通过对已知气动参数的飞机纵向动力学模型进行模拟飞行,分别记录了三组不同控制输入的参数评估所需的时间历程数据,然后分别在高度、速度、迎角、姿态角、角速度、法向过载、轴向过载和升降舵等测量参数的时间历程数据上人为叠加灵敏度、零偏和延时三种误差,利用最小二乘评估法对气动参数进行评估,研究各参数的三种误差对评估结果的影响。结论显示各参数的误差对结果影响量差异明显,延时误差的影响呈非线性。     

Encapsulation of food ingredients

Microencapsulation is a relatively new technology that is used for protection, stabilization, and slow release of food ingredients. The encapsulating or wall materials used generally consist of starch, starch derivatives, proteins, gums, lipids, or any combination of them. Methods of encapsulation of food ingredients include spraydrying, freeze‐drying, fluidized bed‐coating, extrusion, cocrystallization, molecular inclusion, and coacervation. This paper reviews techniques for preparation of microencapsulated food ingredients and choices of coating material. Characterization of microcapsules, mechanisms of controlled release, and efficiency of protection/ stabilization of encapsulated food ingredients are also presented.     

Depth of concussion in cattle shot by penetrating captive bolt

The prevalence of shallow depth of concussion following captive bolt shooting was assessed in 1608 cattle at an abattoir. Depth of concussion was determined in each animal from physical collapse, presence or absence of corneal reflex, normal rhythmic breathing, eyeball rotation, and whether the animal was re-shot. The presence of nystagmus and the absence of tongue protrusion were also monitored as potential indicators of a shallow depth of concussion, and simultaneous noise measurements assessed whether loudness of gun discharge was linked to concussion depth. The prevalence of a shallow depth of concussion was 8% for all cattle and 15% for young bulls. Nystagmus was associated with other indicators of a shallow depth of concussion. Absence of tongue protrusion was not associated with depth of concussion, but could serve as a useful indicator of jaw relaxation and insensibility following exsanguination. Soft-sounding shots (111 dB) when using 4.5 gr cartridges were associated with shallow depth of concussion.     

39—THE FLOW OF LIQUID FROM A JET THROUGH A COMPRESSIBLE POROUS LAYER. PART III: THE CHARACTERISTICS OF LIQUID FLOW THROUGH A COMPRESSIBLE LAYER OF LOOSE WOOL

The effects on the conditions of flow of the surface and configurational properties of the fibres in a compressible porous layer are discussed. The characteristics of a layer of wool are evaluated, and its compressibility is determined. It is shown that, when a liquid of initial uniform pressure flows through a compressible porous medium, the pressure gradient within the medium increases with the distance of flow. The resulting pressure drop is found to depend on a function of the ratio of the downstream to the upstream porosity of the compressible medium. Experimental results are reported for permeable flow through various layers of loose wool; these indicate that, when the flow is disturbed turbulent, the pressure drop through the layers is proportional to the square of the filter velocity. This result is not readily apparent from the graphs of pressure drop against filter velocity because of the compressibility of the fibres.     

21—THE ACETYLATION OF COTTON

An account is given of a study of the effect of the amount of activating agent, the temperature, the catalyst, and the diluents used in the acetylation of cotton with perchloric acid as catalyst. Sulphuric acid was compared with perchloric acid as a catalyst. The effects of traces of water, the amount of acetyl chloride, and the rate of acetylation were studied in the acetylation of cotton with acetyl chloride and pyridine. The conditions in all cases were such that the acetylated cotton retained its fibrous form.     

Headspace solid‐phase microextraction analysis of artificial flavors

Using a non‐equilibrated solid‐phase microextraction/gas chromatography/mass spectrometry technique, differentiation between a wide variety of types and examples of artificial flavors has been demonstrated. Addition of an internal standard to the samples, as received, allowed for the calculation of yields on a µg g^?1 basis for the majority of headspace volatiles. The relative standard deviation values expressed as percentages were between 3 and 5%. The precise nature of the approach coupled with the compound identification capacity of the mass spectrometer afforded the capability to easily differentiate between multiple sources of artificial flavors. With a total analysis time of approximately 30 min and the absence of solvent, this approach has the capability of detecting and quantifying the presence of the low‐molecular‐weight solvents often used in the preparation of artificial flavors. Such a capability represents a distinct advantage over more conventional methods of solvent dilution. Results from conventional gas chromatography/mass selective detector analyses are contrasted and compared with the results obtained from the headspace SPME approach. Copyright © 2005 Society of Chemical Industry     

Biodegradation of genetically modified seeds and plant tissues during composting

BACKGROUND: The increasing global market of genetically modified (GM) crops amplifies the potential for unintentional contamination of food and feed with GM plants. Methods proposed for disposal of crop residues should be assessed to prevent unintended distribution of GM materials. Composting of organic material is inexpensive and location‐independent. The objective of this study was to determine the effectiveness of composting for disposal of GM plants in terms of reducing seed viability and promoting the degradation of endogenous as well as transgenic DNA. RESULTS: Duplicate samples of corn kernels, alfalfa leaves, and GM canola seeds, meal and pellets were sealed in porous nylon bags and implanted in duplicate 85 000 kg (initial weight) feedlot manure compost piles. Samples were collected at intervals over 230 days of composing. Canola seeds and corn kernels were not viable after 14 days of composting with temperatures in the piles exceeding 50 °C. In all samples, PCR analyses revealed that plant endogenous and transgenic fragments were substantially degraded after 230 days of composting. Southern blotting of genomic DNA isolated from canola seeds identified differences in the persistence of endogenous, transgenic, and bacterial DNA. CONCLUSION: Composting GM and non‐GM plant materials with manure rendered seeds non‐viable, and resulted in substantial, although not complete, degradation of endogenous and transgenic plant DNA. This study demonstrates that composting could be effective for disposing of GM crops in the event of their inadvertent entry into the food or feed chain. Copyright © 2010 Crown in the right of Canada. Published by John Wiley & Sons, Ltd     

The inhibitory effect of some amphoteric surfactants on the irritation potential of alkylsulphates

The physico-chemical and biological properties of an amphoteric/anionic system and its behaviour against a proteinic support have been thoroughly investigated. A considerable inhibition of adsorption of SLS (sodium lauryl sulphate) on human callus caused by the presence of definite amounts of AABet (alkyl-amido-betaines) in the treatment bath is observed. These physico-chemical results are in agreement with those obtained by some in vivo biological tests. A mechanism of the process via the formation of mixed micelles is postulated emphasizing the stability of such systems as a function of pH, the influence of the chain length of the amphoteric surfactant and the molar relative ratio SLS/AABet. Consequently, our work offers the possibility of a wide applicability of the synergic mixtures of both types of surfactants to inhibit considerably skin irritation of cosmetic finished products.     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Some Textile Applications of Finite-element Analysis Part I: Finite Elements for Aligned Fibre Assemblies

A new approach to the application of finite elements to aligned-fibre-assembly problems is introduced. This more rigorous application of finite-element analysis will allow the solution of a range of problems that have been impossible to solve by using previous approaches. Difficulties with non-linear material properties and large-scale deformations are overcome by defining the element stiffness matrix in a co-ordinate system based on the energy modes of the element deformation. It is shown how algorithms can be used to supply non-linear relationships for various types of deformation, simplifying the task of using complex material properties. The transformation of the element properties back to a conventional co-ordinate system to allow assembly of all of the elements in the structure is presented.

A two-dimensional element is developed to model aligned fibre assemblies. To maintain fibre continuity between finite elements, twelve degrees of freedom are required for each element. The deformation modes of this element are derived in terms of the conventional co-ordinate system. The results from the finite-element analysis are compared favourably with measurements taken from a deformed array of springs.

This paper is the first part of a series of two papers. Part II will investigate the application of finite elements to yarn mechanics.