基于模糊建模的混炼胶粘度测量     

樊绍胜  王耀南 《湖南农业大学学报(自然科学版)》2004,31(3)

提出了一种在线测量混炼胶粘度的新方法．该方法以模糊建模技术为基础，综合考虑混炼过程各因素对胶料粘度的影响，建立起胶料粘度的在线测量模型．在模糊建模中，采用T-S模型描述胶料粘度变化的非线性过程，提出了一种基于相似性判别的模糊聚类算法以自动确定合适的聚类组数目，并用实数编码的遗传算法优化全局参数，从而获得了规则简化的、具有较高精度的模糊模型．根据此方法，设计了测量装置，并进行了现场试验．试验结果表明模糊模型输出与实验室测量值基本一致，平均误差较低且最大误差未超过1门尼．该方法较大地提高了橡胶混炼的生产效率，为粘度最优控制奠定了基础．  相似文献   

Different biological behaviour of Waldenström macroglobulinemia in two dogs     

F. Gentilini  C. Calzolari  A. Buonacucina  M. Di Tommaso  G. Militerno  P. Famigli Bergamini 《Veterinary and comparative oncology》2005,3(2):87-97

Waldenström Macroglobulinemia is a low‐grade immunosecretory disorder associated with lymphoid tumours, which is rarely reported in veterinary medicine. In this study, we describe two clinical cases of this rare syndrome in dogs, each characterized by a different onset and clinical course. In one case, a hyperacute onset and aggressive behaviour of the neoplasm was observed. Absolute serum viscosity (SV) was retrospectively evaluated in order to explain clinical findings. Rotational viscosimetry showed good precision in measuring SV. Both dogs had SV values higher than a control groups of healthy dogs although only one subject developed hyperviscosity symptoms and complications. At high paraprotein concentrations, a slight reduction of the M‐component was associated with a marked decrease in SV. Thus, this work suggests that SV assessment is a relevant tool for managing monoclonal gammopathies, whose usefulness should be further confirmed in larger cohorts of dogs.  相似文献   

不同粘度矿物油助剂对除草剂活性的影响   总被引：5，自引：1，他引：5  

王金信  张新  肖斌 《农药学学报》2002,4(1):58-63

室内及温室内测定了10种不同粘度矿物油助剂对除草剂防除苘麻和稗草药效的影响及对玉米苗期的安全性。结果表明,10种矿物油助剂均不同程度地增加了氰草津和烟嘧磺隆防除两种杂草的活性。其中粘度为46 mm2/s (40℃)的矿物油乳剂(MOC46)对供试除草剂药效的增强作用最为明显,其次为粘度32 mm2/s (40℃)的矿物油乳剂。10种助剂对氰草津药效的增强作用大于对烟嘧磺隆。MOC46对除草剂活性的增加由高到低依次为:莠去津、氰草津＞莠去津+氰草津、莠去津+烟嘧磺隆、氰草津+烟嘧磺隆＞烟嘧磺隆;对玉米苗期安全性依次为:莠去津、烟嘧磺隆、莠去津+烟嘧磺隆＞莠去津+氰草津、氰草津+烟嘧磺隆＞氰草津。氰草津与MOC46混用对玉米苗期药害较重。  相似文献   

The evolution and application of enzymes in the animal feed industry: the role of data interpretation     

Michael R. Bedford 《British poultry science》2018,59(5):486-493

ABSTRACT

1. Enzymes have been used commercially for nearly 40 years and save significant costs through sparing of expensive nutrients but the mechanism by which this is achieved is still debated.

2. The research focused on non-starch polysaccharidase (NSPase) enzymes is used as an example of where greater progress could have been made if the details of the work had been described more fully and the analysis of the data generated had been broader in scope and more critical.

3. Lack of standardisation of the details presented in the materials and methods has been identified as a significant barrier to meaningful retrospective analysis and thus limits advances in the understanding of the mode of action of these enzymes.

4. The identity of the enzyme employed and its activity is often lacking, and more importantly the purity is rarely disclosed. Contaminant activities which are neither listed nor assayed could play a significant role in the responses observed.

5. The dose optimum of most enzymes is often considerably higher than that employed in most studies. Thus studies claiming synergy between two ‘activities’ should ensure that the response is not related to each enzyme simply augmenting the dose of just one activity in the finished feed. This is a common problem, and coupled with the lack of factorial experiments to justify the presence of each enzyme in a multi-enzyme product, it is not surprising that there is still debate as to whether single or multi-enzymes are best suited poultry rations.

6. The three proposed mechanisms for NSPases (viscosity, cell wall and prebiotic) are discussed, and along with their strengths and weaknesses it is suggested that a re-evaluation of each is needed. Viscosity may have to be re-evaluated as being a function not only of the cereal being fed, but of the age of the animal as well. The cell wall theory as described is poorly modelled in vitro and hence the validity of these data is questioned. The prebiotic theory may need significant modification as it appears that the quantities of oligomers produced are insufficient to generate the additional volatile fatty acids (VFA)’s reported. It is likely that all three mechanisms play a role in the responses observed, but the prebiotic mechanism probably plays by far the most important part in low viscosity diets.

7. Future research would be improved if it considered all potential mechanisms when designing a trial. Significant failings are apparent as a result of adherence to tenets in explanation of the results. Most importantly, it should be emphasised that a hypothesis is there to be tested, not defended.  相似文献   

Effect of process conditions and amylose/amylopectin ratio on the pasting behavior of maize starch: A modeling approach     

《Journal of Cereal Science》2020

The effects of different process conditions on the pasting behavior of the 14%, w/w suspensions of high amylose, waxy and normal maize starches at mixing speeds of 50, 160 and 250 rpm with the heating rates of 2.5, 5 and 10 °C/min were investigated. In addition, the impact of the starch mixture with an amylose-amylopectin ratio of 0–70% at 160 rpm and a heating rate of 5 °C/min on the pasting parameters was studied. According to the results, when stirring speed decreased from 250 rpm to 50 rpm, the peak viscosity dramatically increased. Furthermore, both heating and stirring rates significantly affected the pasting properties (p < 0.05). The amylose content of maize starch had a negative correlation with peak viscosity, trough viscosity, breakdown viscosity, final viscosity, and setback viscosity. Besides, syneresis values decreased as amylose content decreased from 70% to 0%. According to the kinetic modelling of pasting curves, starch coefficients were found to be higher than 1 for all starches, indicating that the penetration of water into starch granules increased granule swelling rate. The findings of the present study confirmed that both process conditions and amylose/amylopectin ratio can be optimized without necessity of starch modification to obtain the products with the desired quality.  相似文献   

Thermal and rheological properties of brown flour from Indica rice     

《Journal of Cereal Science》2016

The thermal, paste and rheological properties of brown flours from four Indica rice subspecies with different amylose content were examined using Differential scanning calorimetry (DSC), Brabender Viscometer and rheometer. Peak, final and setback viscosities (p < 0.05) increased with increasing amylose content from Brabender micro Visco-Amylo-Graph (MVA), but the phase transition temperatures of brown rice flour from DSC (p < 0.05) decreased with increasing amylose content. Rheological properties were determined by steady shear, small amplitude oscillatory shear (SAOS) and thixotropic experiments. SAOS results showed a gel-like viscoelastic behavior with G′ higher than G″. Steady-shear results showed that the brown rice flour exhibited a non-Newtonian shear-thinning behavior and the flow curves can be well described by the Herschel-Bulkley model. The upward-downward rheograms showed that brown rice flour gel, except IR-1, had a hysteresis loop, indicating a strong thixotropic behavior.  相似文献   

不同水分,温度条件下CO2浓度对大米品质的影响   总被引：5，自引：2，他引：5  

高影  杨建新 《粮食储藏》1997,26(1):3-14

试验选用当年新收获的稻谷加工成的水分为１３．９％、１４．７％和１６．０％的大米，在２３℃和３３℃的恒温室中，将７种不同浓度的ＣＯ２经减压调湿后通入粮堆。定期取样，测定大米的脂肪酸、水溶酸、还原糖、非还原糖、粘度和过氧化物酶活性的变化。试验结果表明：１３．９％水分的大米在２３℃下储藏，各种浓度ＣＯ２对大部分品质指标影响不显著，ＣＯ２的保质作用不明显；１４．７％水分的大米在２３℃储藏，ＣＯ２对个别品质  相似文献   

Research on Optimum System of Slag Making of ANYANG Iron & Steel CO.BF     

Wen Guangyuan Peng Henian 《保鲜与加工》1997,(6):30-35

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Experiments on Forced Convective Heat Transfer of Oil in Tubesw with twisted-Tape Inserts     

Wu Shuangying  Xin Mingdao 《保鲜与加工》1995,(1):113-117

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浑浊型饲用微生态菌剂悬浮剂的制备及稳定性研究     

浑浊型饲用微生态菌剂悬浮剂的制备及稳定性研究 《畜牧与饲料科学》2021,42(6):13-17

[目的] 建立一种浑浊型微生态菌剂悬浮剂的制备方法,并对其稳定性进行评价。[方法] 以黄原胶和羧甲基纤维素钠为稳定剂,以饲用微生态菌剂干粉为悬浮成分,制备微生物水悬浮体系。对制备的悬浮剂进行稳定性评价,测定指标包括稳定系数、黏度、存放稳定性、冷贮存稳定性和活菌总数。[结果] 随着稳定剂添加比例的增加,悬浮剂的稳定系数逐渐增加。添加0.20%稳定剂,体系的稳定系数达到91.38%,极显著（P<0.01）高于空白对照组。悬浮体系的黏度随着稳定剂添加量的增加和贮存温度的降低而增大,当稳定剂添加比例为0.20%时,体系不出现分层现象,达到稳定状态。经过24 h冷贮存（4 ℃）后,添加0.10%稳定剂的悬浮剂活菌数出现下降,添加0.10%~0.25%稳定剂显著（P<0.05）低于空白对照组,但仍维持在10⁹ CFU/mL以上。[结论] 稳定剂添加量为0.20%时,饲用微生态菌剂悬浮剂无分层现象出现,无论常温还是冷贮存24 h后,制成的悬浮剂中活菌数均保持在10⁹ CFU/mL以上,能够保证饲用微生态菌剂的有效活菌数。  相似文献