Cold chain database development and application as a tool for the cold chain management and food quality evaluation

Cold chain management can optimize freshness and safety to the consumer end. Within FRISBEE European project (http://frisbee-project.eu) a web-based platform was developed for temperature conditions data collection throughout the chilled and frozen food supply chain. Data including all cold chain stages (industry, distributors, retailers and consumers), were collected. This extensive database comprising more than 14,000 time-Temperature (t–T) profiles can serve as a valuable Cold Chain Management tool. The user can define a sequence of cold chain stages for selected food products. The Cold Chain Predictor (CCP) software based on the Cold Chain Database (CCD) allows calculation of product shelf-life status at different cold chain stages based on existing or user defined kinetic data. Conducted field tests expanded the Cold Chain Database and validated the software. The developed tools offer the potential to run simulation scenarios based on real cold chain data and contribute to effective cold chain improvement and management.     

A novel Temperature–Humidity–Time defrosting control method based on a frosting map for air-source heat pumps

To improve the defrosting accuracy and the energy efficiency of the air-source heat pump (ASHP) under frosting and defrosting conditions, a novel Temperature–Humidity–Time (T–H–T) defrosting control method, based on a frosting map for the ASHP unit, is proposed in this paper. A field test was conducted for two heating seasons, to verify the feasibility and applicability of the T–H–T method. The advantages of the T–H–T method, compared to the conventional Temperature–Time (T–T) defrosting control method, are presented. In total, eight cases are shown in this paper. Cases 1 to 4 were chosen to reveal the T–H–T performance under different frosting conditions. It was found that no matter what kind of frosting conditions, defrosting was always initiated in a similar situation: ∼90% of the outdoor coil surface was covered by frost; the temperature difference between the compressor suction and discharge increased by ∼20%; and the heating capacity decreased by ∼30%. These results indicate that the T–H–T method can make an accurate decision under different frosting conditions. Cases 5a, 5b and Cases 6a, 6b were two groups of cases to compare the advantages of the T–H–T method against the conventional T–T method. Cases 5a and 5b were chosen for the non-frosting condition. It was found that the T–T method initiated the defrosting operation 31 times within 24 h. However, none of the defrosting operations was conducted for the T–H–T method. Cases 6a and 6b were chosen to compare these two methods under consecutive and variable frosting conditions. For the T–T method, 63% of the defrosting processes were found to be executed under conditions where defrosting was not necessary. However, for the T–H–T method, all the defrosting controls were found to be accurate and reasonable. These results indicated that the novel T–H–T method is suitable for the defrosting control of the ASHP, and has a more competitive performance than the conventional T–T method.     

水溶性菁染料与类脂物混合单分子膜中J-聚集体形成的研究

报道了具有相同发色团,并有不同电荷的二种菁染料单分子膜中J-聚集体的形成。测定了单分子膜的π/A,△V/A曲线,反射光谱及吸收光谱。从实验结果得出:带正电荷的染料与花生酸混合形成单分子膜后,膜中染料的二聚体与J-聚集体随着表面压力改变存在着一个平衡。而带负电荷的染料与二十烷基胺成膜后,即使在很低的表面压下也有J-聚集体形成。同时染料分子在水面上的取向是各向异性。     

Comparison of the refrigerants HFC 134a and CFC 12

A comparison of the refrigerants HFC 134a and CFC 12 has been carried out and the results from a theoretical analysis and from tests with an open piston compressor are reported in this paper. The results indicate that the tested compressor will give a greater refrigerating capacity with HFC 134a than with CFC 12 for certain operating conditions. However, the results also indicate an increased operating power for the compressor over the entire temperature range. As a result the coefficient of performance is decreased. Another noticeable result is dependency of the compressor's isentropic efficiency on temperature when using HFC 134a. This might be explained by the properties of the polyalkene glycol oil which is used with HFC 134a. The increased cost of using HFC 134a is justified if the environmental aspects are considered and the practical problems, such as the influence on the material in the refrigeration cycle, can be solved.     

How does Government Procurement Law affect bidding price competition in Taiwan?

To conform with the requirements of the international Government Procurement Agreement and the regulations of the World Trade Organization, the Taiwan Government Procurement Law (GPL) was enacted in 1999. The main points of the agreement and barriers affecting price competition are illustrated. Award prices for subcentral government civil engineering projects are compared before and after the law went into effect. The result suggests that civil engineering prices have decreased significantly since the introduction of the law, that the transparent and open-tendering system enforced by the law has led to an increase in competition, and that tender prices decreased during the initial period. During the same period, construction companies' average rate of profit on sales moved from positive to negative. It is concluded that severe bidding competition is expected after Taiwan completes accession to the agreement.     

一种有效的违章车辆抓拍方法

在道路监控系统中，违章车辆的抓拍是至关重要的一环，抓拍效果的好坏直接影响后续处理的进行。文章提出一种较有效的违章车辆的抓拍方法。实践证明，该方法实时性好。准确度高，具有较高的实用价值。     

用800nm表面态方法和低温方法结合吸收区的半导体可饱和吸收镜实现掺钛蓝宝石激光克尔镜锁模

研制了一种新型的80 0 nm布拉格反射镜型半导体可饱和吸收镜,其吸收区是低温方法和表面态方法相结合.用该吸收体实现了氩离子激光器泵浦的掺钛蓝宝石激光器被动锁模,脉冲宽度达到4 0 fs,光谱带宽为5 6 nm,后者意味着它可以支持2 0 fs的锁模.脉冲序列的重复率为97.5 MHz,泵浦源为4 .4 5 W下平均输出功率为30 0 m W.     

刀片系列化对可转位球头立铣刀加工精度的影响

在可转位球头立铣刀的设计中 ,为了减少刀片规格和利于刀片的标准化 ,要将理论上求得的刀片圆弧半径圆整成整数 ,本文分析和计算了由此而产生的加工表面形状误差