Textural Determination of 'Montmorency' Cherries Using Shear/Compression and Stone Removal Forces

Selection of firm tart cherry cultivars has traditionally been limited by instrumental limitations when measuring cherry texture. Current methods estimate cherry texture by evaluating skin strength and/or turgor pressure rather than pericarp firmness. An attachment to a Kramer Shear Press was designed and built to determine the force required for stone removal. Pericarp strength was measured by placing pitted cherries in a shear/compression cell and measuring shear, compression, and extrusion forces. Preliminary testing indicated stone removal force with shear/compression force may be useful for determining texture of tart cherries in cultivar screening studies.     

棉纺厂用新型纤维长度强力测试仪

在过去的三年里,Textechno公司发明了一种针对棉纺厂的新型测试设备.这个设备可用于纤维长度分配的绝对测定和切断短纤维强力或伸长率的检测.测试仪器既可用于测量棉条也可用于测量原棉.此处介绍了测量原理、操作方法以及新型束纤维的强力测试和长度测试.     

F-12芳纶织物输送带的制备及其性能

为提高F-12芳纶织物与橡胶之间的粘结性能,采用环氧树脂和偶联剂A187对F-12芳纶织物进行改性。通过成膜分析确定出环氧树脂的最佳用量;通过改性后F-12芳纶织物的浸水高度以及浸渍间苯二酚-甲醛树脂乳液后的拉伸强度和断裂强度测试,确定出偶联剂A187的最佳用量。在此基础上,对改性后的F-12芳纶织物进行硫化成型,测试织物与橡胶的剥离强度确定出最佳改性工艺。结果表明:环氧树脂用量为25%(o.w.f),偶联剂A187用量为1.2%(o.w.f)时,制备的F-12芳纶织物轻薄输送带的综合性能最佳;改性后浸水高度值最低的F-12芳纶织物制备的轻薄输送带的剥离强力达到最高,为12.1 N/mm,其剥离强度高于行业标准;制备的单层铺层输送带的扯断强力为6 495.25 N,断裂伸长率为13%,双层铺层输送带的扯断强力为14 493.25 N,断裂伸长率为14%。     

卫生纸抗张强度测量不确定度的评定

按照测量不确定度评定的基本方法和程序对卫生纸抗张强度测量结果的不确定度进行了评定,不确定度来源主要是抗张力F-的重复性测量,其次为电子万能试验机校准和试样宽度;卫生纸抗张强度测量结果的扩展不确定度是1.6N/m,包含因子为2;在卫生纸抗张强度测量过程中,应均匀取样,并提高操作者的熟练程度。     

原木材积自动化检测系统

提出了基于自动化测试技术与计算机视觉技术的原木检尺新方法，设计、研制了相应的自动化检尺系统。工控机控制高分辨率的工业CCD数字成像单元对一手原木端面成像，并把图像数据库传输到工控机。基于目前施行的国家标准，结合待识别对象的特点，设计、开发了相应的图像处理和识别软件。图像识别结果经必要的人工交互处理后按照国家标准进行计算，其结果存入专用数据库。数据库对自动化检尺过程与结果进行管理和监督。实测结果表明，自动化检尺系统的检尺方法符合国家标准，检尺结果稳定、可靠，检测误差小于1%。     

陶瓷结合剂对金刚石颗粒把持力检测的研究

针对陶瓷金刚石磨具结合剂对金刚石颗粒的把持力问题,文章分析了把持力的特征,提出了基于抗拉强度试验的把持力检测办法。通过对金刚石颗粒受力分析和理想化假设,建立了把持力计算的力学模型。推导得出把持力与磨具抗拉强度的关系的数学模型,通过系列实验的数据和计算机软件算出了结合剂对金刚石颗粒的把持力。     

单纤维强力与束纤维强力关系的探讨

为了探讨单纤维强力与束纤维强力的关系,对PBT改性涤纶和羊毛分别进行了单纤维强力和束纤维强力试验,通过分析试验结果,提出了主体强力、品质强力、平均强力、弱强纤维强力和超强纤维强力的纤维强力指标体系,认为纤维强力指标体系中各强力指标与各自的单纤维性能之间存在着一定的联系;另外,通过改变纤维束的根数,得出束纤维强力折算单纤维强力的"极限阶段"是理想的转化范围.     

The strength and stiffness of perimysial connective tissue isolated from cooked beef muscle

Thick transverse slices of bovine M. semitendinosus were cooked for 1 h at 50°–90° and then cooled. Perimysial connective tissue was dissected from the cooked meat and subjected to mechanical testing in a small-scale device. The initial ‘toe’ region of the J-shaped load-extension curve was progressively lost with increasing temperature, the curve becoming more nearly linear after cooking at 90°C. These effects are explained on the basis of the progressive straightening out of the crimps from the collagen fibres, the crimps becoming finally lost at approximately 70°C. The final stiffness of the perimysium at greater extensions was unchanged at higher temperatures. Breaking strength increased from raw to cooked at 50°C, thereafter decreasing at cooking temperatures up to 90°C. it is proposed that this technique of testing isolated perimysium gives a valuable means of directly measuring the effects of cooking, or other treatments, on the intrinsic properties of perimysial collagenous material. Quantitative knowledge of these will help to determine its contribution to the overall mechanical properties, and hence eating quality, of cooked meat.     

纺织品服装纽扣拉伸强力测试方法

纽扣拉伸强力是纺织品服装的重要服用性能之一,但目前还没有相关的检验标准出台。以不同类型的纽扣为研究对象,比较了断裂法和定负荷法对纽扣拉伸强力测定结果的影响。研究发现,断裂法可准确测定不同类型纺织品服装的纽扣拉伸强力;定负荷法可测定纽扣滑脱、纽扣与织物缝接处缝线断裂、织物破裂、纽扣破裂、拷纽分离脱落等状况。     

Tensile strength prediction of irregular fibres using diameter-dependent Weibull analysis

A modified Weibull model incorporating the within-fibre diameter variation is applied to examine the fibre diameter effect on the strength of single fibres. Australian Superfine Merino Wool (ASFW) and Inner Mongolia Cashmere (IMC) were used in the present work, since these animal fibres tend to have relatively large diameter variations. To determine single fibre strength, tensile measurements were carried out for fibres with diameters varying between 9 and 21?μm at a constant gauge length. It was found that an increase in the diameter disparity along the fibre reduces the strength of fibres. To validate this, the accuracy of predicting weak-link scaling was evaluated; the results showed that the application of modified Weibull distribution gives a better relationship with the empirical data than the standard Weibull model. The results suggest that the modified Weibull model is more accurate in predicting the size dependence and strength of single fibres with diameter variations.     

OSCILLATORY PROBE RHEOMETRY AS A TOOL FOR DETERMINING THE RHEOLOGICAL PROPERTIES OF STARCH-WATER SYSTEMS 1

An oscillatory probe rheometer was effective at measuring the viscosity of starch pastes and the viscoelastic properties of starch gels. Because low shear strains were applied, the integrity of the gel was not disrupted during the testing. As the starch concentration of the systems increased, the complex modulus (G*) and storage modulus (G′) increased. At 20°C, the strength of the resulting gels, as measured by log G′, was a linear function of starch concentration. Loss tangent values (G″/G′) could be used to determine the approximate temperature at which the sol became a gel. As the starch concentration of the systems increased, the temperature of the sol to gel transformation increased from approximately 35°C (5% starch) to 60°C (10% starch).     

Quality control of glulam: shear testing of bondlines

In quality control of glulam, shear testing of bondlines is required. However, in relevant standards the method of applying shear stress to the bondline is only exemplified by a principle schematic. Based on this schematic a considerable variety of test equipments is in use nowadays. Depending on the respective construction of the test equipment as well as on the execution of testing, the resulting stress in the bondline is not pure shear but rather a combination of shear and normal stresses. When the normal stresses are acting as tensile stresses perpendicular to the bondline, the registered shear strength values range considerably below the pure shear stress level, whereas compression stresses perpendicular to the grain lead to an overestimation of the shear strength of the bondline. To overcome this deficiency, a prototype of a modified shear test device was developed, which ensures a clearly defined state of shear loading of the specimens. Based on extensive comparative testing it is shown that by performing compression tests at an oblique angle to the grain of 14° the above mentioned problems can be avoided.     

Novel derivatives of 3D woven T-shaped composites with improved performance

Conventional 3D woven T-shaped preforms were modified for improving joint/ peel off strength of associated T-shaped polymeric composites. Preforms were modified at weaving level by preferred yarns orientations for better performance in associated composites. Major modifications studied are; the addition of supporting layer, single or double-crossing in joint layers and crossing along with supporting layer (in a single sample). Novel derivatives were compared with conventionally used (on-loom and off-loom) T-shaped 3D woven composites. Microscopic analysis was also carried out to analyze the orientation of yarns and analysis of samples from failure point after testing. By combined variation of crossing and supporting layers improvement of 47.37% in peel off strength and 70.37% in impact strength was observed. Modified T shapes can serve to be a good replacement for conventional T-shaped stiffener (used to avoid folding under loads) and in joints.     

Development and Characteristics of Modified Agar Gels

Icing formulations that are being used in bakery and confectionary industries have a lot of post storage problems. The use of stabilizers like agar involves a high cost due to the dissolving process. This study involved the development of freeze-dried and drum-dried agars which are soluble in warm water (55°C). The two modified products were compared with the unmodified one to determine differences in gel formation, gel strength, viscosity and micro structure. The agar modified by drum drying dissolved at 55°C and its gel had characteristics similar to the gel made with unmodified agar heated to 100°C.     

Intrumentierung eines Pendelschlagwerkes für die Holzprüfung

The results of the conventional impact bending test with the pendulum hammer according to DIN 52 189 show the impact strength (shock resistance), which is defined as the energy of impact as related to the cross-section of the specimen. To obtain more information about fracture mechanics, a pendulum hammer was prepared with a load indicating system, using strain gauges for measuring the power as a function of time. The data are registered by an oscilloscope and documented by anx-y-recorder, or are transferred to a computer for further data processing. The results show the suitability of the testing system and permit first interpretations of the graphs.     

纱线和织物的弯曲刚度

归纳了纱线和织物弯曲刚度已有的测量方法特征及意义，并简要地阐述了改进单纤维电子强力仪测纱线弯曲性能的方法和实验结果，。同时对影响纱线和织物弯曲刚度的因素分别进行了详细的讨论，提出了解决纱线弯曲性能与织物弯曲性能对应测量方法和建立其间理论关系的重要性。     

蜂窝微孔改性涤纶针织物服用性能测试与分析

使用蜂窝微孔改性涤纶纱、莫代尔纱、天丝A100纱及棉纱开发了3种针织物,分别测试它们的顶破性能、抗起球性能、悬垂性能、毛细管效应、导湿性能、透湿性能和透气性能。测试结果表明:蜂窝微孔改性涤纶针织物具有优异的抗起球性能、透湿性能和透气性能;顶破强力、悬垂性能、毛细芯吸高度和导湿性能介于改性涤纶与棉合股编织织物,改性涤纶与莫代尔、天丝A100纱合股编织织物之间。     

Festigkeitsuntersuchungen an Flächeneckverbindungen im Korpusmöbelbau

Corner-joints of two different particleboards, as they are used in the manufacture of case-type furniture, were prepared in 13 variations, fixed and detachable. These corner-jointed test specimens were subjected to various load tests to determine the failure under bending, as well as their angular stiffness. It became evident that the strength of the joints is influenced by the type of joint and by the particle-board quality. Especially in the case of mitre-jointing, the strength also depends on the loading method. The knowledge of these strength data ist necessary for predeterming the suitability of furniture desings, as well as for establishing standards for furniture testing.     

Comparative analysis of thermally modified and native spruce loaded perpendicular to the grain

The aim of this work was to analyse the material behaviour of thermally modified and native spruce by load applied perpendicularly to the grain. Therefore, thermally modified and native samples were prepared for bending tests with the load in tangential direction. The bending strength in radial direction decreases significantly with the thermal treatment. The fracture surfaces in the tangential section of the bending samples after testing were analysed with a scanning electron microscope. For native samples, the typical failure was found in the intercellular area. For thermally modified samples, failure of the entire cell wall was observed. The material behaviour is more brittle, as demonstrated by the load-deflection curves, but also by anatomical studies of the fracture surfaces.     

变性淀粉浆料共性质量指标对上浆的影响

对纺织用变性淀粉浆料的水分、灰分、蛋白质、pH值等各项共性质量指标进行了分析，探讨了各项共性质量指标对上浆和浆纱质量的影响，并对变性淀粉浆料粘度的测试仪器进行了调研，对测试方法和测试时的浆液浓度进行了研究，提出了测定粘度时有关浆液浓度的修正建议。