新型立式马铃薯连续去皮机仿真设计

随着时代的发展,人们对食品加工业越来越重视。基于Solid Works的马铃薯连续去皮机三维仿真设计,分析以往立式去皮机的工作原理及去皮效果,在原有传统型去皮工序基础上,设计新型马铃薯立式去皮机。该去皮机将马铃薯准备、清洗、去皮加工、再清洗及卸料工序形成一整套循环系统,大大减少了人工环节,提高了去皮效率。并运用三维软件Solid Works完成马铃薯去皮机仿真试验。     

一种新型食用甘蔗自动去皮装置的设计与研究

为解决目前甘蔗人工去皮效率低、劳动强度大、安全性低等问题,设计了新型食用甘蔗自动去皮装置.动力源通过传动机构将动力分路传递给去皮执行机构和甘蔗旋转控制机构,电控系统检测去皮机构位置并控制其往复切削运动.甘蔗旋转控制机构实现甘蔗的间歇性旋转,通过与去皮执行机构的运动协调,完成甘蔗去皮.通过对关键机构的设计、仿真分析和试验,表明所设计的装置能够有效进行甘蔗去皮工作,结构设计合理,达到设计要求.     

TQLZ型自衡振动筛动力学之模态分析

以国内某机械厂生产的TQLZ2000自衡振动筛为研究对象,针对该振动筛筛箱侧板易于断裂,使用寿命相对较短等问题,利用有限元分析方法,对该振动筛筛箱进行了模态分析。结果表明,该振动筛在工作时避开了载荷频率,不会发生共振,符合动态设计要求,但在振动筛开始工作和停止工作时的瞬间会发生短时共振,由于时间短,对振动筛结构及振动性质影响不会太大。为进行结构动力学分析奠定了基础,同时为该类机械的设计提供参考。     

青核桃块状去皮机的研制

结合当前青核桃去皮机械存在脱皮后会将青皮打成液汁状的问题,对青核桃去皮原理进行研究,设计一种经济实用型青核桃块状去皮机,对内滚圆筒、青皮剥离机构、分离机构等进行设计,设计的青核桃去皮机结构简单,操作方便,经济安全,青核桃去皮效率达到98.33%,破损率2%,减少了去皮过程青皮汁液对机器腐蚀和环境污染的问题,有很好的开发前景。     

振动电机激振的振动筛运动分析及主参数设计

从振动筛的振动体系组成出发，分析了筛体的运动，提出了振动筛设计的理论基础和主参数设计计算方法。     

往复振动筛运动参数的优化设计

本文根据往复振动筛筛选分级的要求及特点,建立了往复振动筛运动参数优化设计的数学模型,计算结果表明,采用本文建立的优化数学模型设计出的运动参数与进口振动筛实际选用参数基本吻合。     

TQLZ自衡振动筛疲劳分析

以TQLZ自衡振动筛为研究对象,针对该振动筛在使用过程中筛箱经常出现的疲劳断裂问题,利用有限元分析方法,对该振动筛筛箱进行了静力分析和疲劳分析等。通过静力分析,得到静态应力分布情况,结果表明筛箱满足材料强度设计要求,之后进行疲劳分析,发现在该振动筛筛箱的最大应力处,其损坏值已经达到366,远远超过了1,表明该筛箱疲劳寿命低,与工程实际基本相符。为该振动筛下一步进行结构优化设计奠定了理论基础,同时为该类机械的设计提供参考。     

基于运动控制器的甘蔗去皮机设计

设计一种基于运动控制器的甘蔗去皮机,可实现入料、去皮、出料整个过程的自动化。该机入料和出料采取两套机构,针对甘蔗的特性设计弹性去皮刀具,并采用运动控制器作为控制系统的核心单元。经实验验证:该样机设计的功率最大为1kW,最大去皮直径为50 mm,最小去皮直径为20mm,最大切削速度可以达到250kg/h,相同时间可节约电量约30%,可保证甘蔗去皮的均匀性与一致性。     

基于离散元法的玉米颗粒振动筛分过程模拟研究

为了探究玉米颗粒在直线振动筛面上的运动情况,课题组以散体力学为基础,依据离散单元法分析玉米颗粒振动筛分机理。通过建立直线振动筛三维模型,分析玉米颗粒在振动筛面上的运动,应用可视化离散元模拟软件EDEM分析振动筛面在上下直线运动的情况下,玉米颗粒速度变化情况得出以玉米圆颗粒为基础模型,直线振动筛相关的一些参数的变化对筛分过程中颗粒速度和位置的影响。仿真结果表明:不同形状的筛孔、不同下落高度和不同形状颗粒都对筛分效果产生影响。课题组的研究为设计和优化直线振动筛提供了参考。     

胡萝卜复合磷酸盐去皮试验研究

试验通过正交设计L9(34),采用复合磷酸盐去皮法对胡萝卜去皮工艺进行了研究,结果表明,以含4%磷酸钠、0.5%磷酸氢二钠和0.5%焦磷酸钠的混合液,95℃热烫3min去皮效果最好,去皮率达100%,且胡萝卜色泽良好,果肉无腐蚀。     

Viscoelastic Properties of Tomato Juice: Applicability of the Cox–Merz Rule

Tomato is one of the most important vegetables for the food industry. Rheological characterization of food is important for products, equipments, and unit operations design and evaluation. It is necessary for process optimization and high-quality products assurance. However, the works in literature present variable data, and some rheological characterization, as viscoelastic properties, are still scarce. The present work has evaluated the viscoelastic properties of tomato juice, as well as the applicability of the Cox–Merz rule. Tomato juice has shown dominant elastic properties rather than the viscous ones and could be classified as a weak gel (storage modulus higher then loss modulus). Moreover, due to the low pulp content, it has shown low viscoelastic behavior, with small dependency of oscillatory of the storage modulus. The rheological oscillatory and steady-state shear rheological properties of tomato juice were then correlated by two linear modifications on the Cox–Merz rule. The obtained values are in agreement with those described in the literature for other food products. The obtained data are potentially useful for future studies on food properties and process design.     

Validation of a large amplitude oscillatory shear protocol

Oscillatory shear rheology plays a valuable role in assessing rheological properties of viscoelastic materials. In the linear viscoelastic region (LVR), the stress response to a strain input comprises only the first harmonic. Beyond the LVR, higher-order harmonics have significant contributions, which are not accounted for in the traditional calculation of viscoelastic moduli. Previous study has developed a mathematical framework that accounted for higher-order harmonics during large amplitude oscillatory shear (LAOS), yielding a physical interpretation to nonlinear data. However, this protocol was not formally validated with model elastic and viscous systems. To that end, a model elastic solid and viscous liquid were tested using LAOS to compare the protocol to standard oscillatory data and the known nonlinear properties of both systems. Good agreement (α = 0.05) was shown between first-order harmonic viscoelastic moduli data for both systems in the linear region. The protocol correctly indicated linear-to-nonlinear transitions of the elastic system, strain-independent linear behavior of the viscous system, and strain-hardening behavior of the elastic system in the nonlinear region. These results indicate the validity of the protocol, which may be applied to food systems to give valuable insights into nonlinear behavior and elucidate structural keys to texture design.     

Oscillatory water sorption dynamics of bread crust

Step-wise and oscillatory gravimetric sorption experiments were used to study the equilibrium and dynamic water sorption behavior of bread crust. Water uptake kinetics is strongly related to crispness retention of composite products consisting of a dry crispy part and a more humid and soft part. We show that oscillatory sorption experiments of bread crusts could be very well described by a Fickian diffusion model. Many essential features, such as the shape of the oscillatory sorption curves, and the dependency of water sorption rates on time, time-interval between successive step-wise changes in relative humidity, and particle size are understood now to a great detail.     

Oscillatory Sorption Tests for Determining the Water-transport Properties of Chitosan-based Edible Films

ABSTRACT: A new approach based on the use of the oscillatory sorption tests is proposed for determining the water-transport properties of chitosan-based edible films. Stepwise sorption tests, oscillatory sorption tests, and water-permeation tests were conducted at 25 °C on chitosan edible films to elucidate the advantage of using the proposed approach. A mathematical model, which accounts for the superposition of polymer relaxation and stochastic diffusion, was used to fit and to predict the experimental data. Results suggest that wherever water-sorption kinetic is controlled by polymer relaxation, oscillatory sorption tests should be used instead of stepwise sorption tests to determine the relationship between water-diffusion coefficient and the local water concentration.     

EFFECT OF SHEAR ON THE NEMATIC MESOPHASE OF THE WHEAT STORAGE PROTEIN A-GLIADIN

The nematic mesophase of A-gliadin exhibits rheopectic properties under oscillatory shear but not under unidirectional shear. The solutions change from a viscous sol to a stable gel after 28 cycles of oscillatory shear at 0.17 Hz, 22°C. The interaction energy between A-gliadin fibrils is estimated as 10.2 Kcal mole below 35°C and 6.25 Kcal/mole above 35°C with the change in interaction energy coinciding with a known change in the tertiary structure of the molecule. It is suggested that the different response of the solutions to oscillatory shear versus unidirectional shear results from the asymmetric tactoids present in the solutions and that any system which forms nematic tactoidal solutions would exhibit similar properties.     

对乙酰氨基酚-KBrO_3-H_2SO_4体系化学振荡反应的研究

本文主要研究在CSTR(连续搅拌反应器)条件下一些因素对化学振荡的影响,得到该非催化振荡的最佳条件和振荡范围,以及反应总活化能。BZ型反应催化剂对非催化振荡有不同的影响。本文发现除Mn~(2+),Ce~(3+)之外,{Fe(phen)_3}~(2+)也能使停振的非催化振荡复活。当BZ催化剂加入到非催化振荡体系中。整个体系转变成非催化和催化振荡的藕合体系。实验事实说明:非催化振荡的有机产物是随后催化振荡反应物。在CSTR中利用铂电极和分光光度计同时检测出{Fe(phen)_3}~(2+)的振荡行为。     

Measurement of Gelpoint Temperature and Modulus of Pectin Gels

Methods which permit the measurement of gelpoint (setting) temperature (T_gel) and rigidity modulus (G) of pectin gels were improved. Gel development on cooling was determined with an oscillatory pressure testing device capable of detecting a modulus as low as 3 Pa and strain values no greater than 5∞10^?3. Sample was set in a glass “U” tube during pressure oscillatory assay for T_gel determination, and transferred after gelling in the same tube for G modulus determination with modified Saunders-Ward apparatus. Results confirmed rheological behavior reported for these kinds of gels and compared favorably with small amplitude oscillatory measurements performed with a stress controlled rheometer using cone and plate (4°, dia = 4 cm) geometry at different frequencies (0.5 to 1.5 Hz) and cooling rates (1 to 3°C/min).     

Comparison of rheological and colorimetric measurements to determine α-amylase activity for malt used for the beverage Bozo

In the current study, rheological and colorimetric methods were compared for determination of α-amylase activity of grain malt, used for Kyrgyz traditional fermented beverage Bozo. The highest α-amylase activity determined by colorimetric method was found in barley malt (32.83 A), followed by wheat (32.09 A), and was lowest in millet malt (10.82 A) and maize malt (10.76 A). Rheological parameters of millet porridge without and with malt were studied. The liquefaction effect of millet porridge after addition of malt was determined with rotational and oscillatory measurements. Results from statistical analysis (partial least squares regression) revealed that oscillatory rheological parameters (yield stress τ, deformation γ, and storage modulus G′) could be an effective indicator to predict the α-amylase activity of the investigated malt with R² = 0.9572. Consequently, rheological oscillatory measurements were recommended as an alternative tool to determine α-amylase activity of grain malt.     

金属—半导体界面附近的空位电子态

本文用紧束缚模型发展了金属—半导体界面附近的空位理论。研究结果发现:空位对它附近区域的态密度有一定影响;空位的生成能随空位-界面间距的变化是一个振荡函数;空位趋向于朝界面处吸引。当系统中同时存在两个空位时,由于介质极化,空位之间要发生间接相互作用,其间接相互作用能随空位-空位间距的改变发生振荡。