Experimental study of forced convective boiling for non-azeotropic refrigerant mixtures R-22/R-124 in horizontal smooth tube

In this article, the experiment is carried out with four stages of test section and new experimental data of non-azeotropic refrigerant mixtures R-22/R-124 are presented. Existing correlations are analysed and new ones are proposed for pure refrigerants. The nucleate boiling correlation of the refrigerant mixtures is modified so as to obtain the evaporation heat transfer coefficient of the refrigerant mixtures in a smooth tube. The result shows that the majority of the predictions fall within ±30% of the experiments.     

Artificial immune system for optimal design of composite hydrogen storage vessel

Based on the clonal selection principle in the biological immunology, an artificial immune system (AIS) is proposed to optimize the weight of Al-carbon fiber/epoxy composite hydrogen storage vessels under burst pressure constraint. The AIS simulates the generation of the antigens, the combination of the antigens and antibodies, and the selection, cloning and hypermutation of B cells, the maintenance of diverse antibody cells, the generation of the memory cells with high affinities and the death of the antibody cells with low affinities. Effects of the antibody size and the iterative number on the optimization results are explored. By comparison, the AIS shows higher search velocity and precision than the genetic algorithm and simulated annealing.     

Synthesis and characterization of Y_2O_2S:Eu~(3+),Mg~(2+),Ti~(4+) nanorods via a solvothermal routine

Y2O2S:Eu3+,Mg2+,Ti4+ nanorods were prepared by a solvothermal procedure.Rod-like Y(OH)3 was firstly synthesized by hydrothermal method to serve as the precursor.Y2O2S:Eu3+,Mg2+,Ti4+ powders were obtained by calcinating the precursor at CS2 atmosphere.The Y2O2S:Eu3+,Mg2+,Ti4+ phosphor with diameters of 30-50 nm and lengths up to 200-400 nm inherited the rod-like shape from the precursor after calcined at CS2 atmosphere.The Y2O2S:Eu3+,Mg2+,Ti4+ nanorods showed hexagonal pure phase,good dispersion and exhibite...     

Shield tunneling and environment protection in Shanghai soft ground

Large scale and intensive metro construction through dense urban area increases sharply the impaction on risk control and environment protection. Three typical cases of shield crossing building above ground (SCBA), shield crossing tunnel from above (SCTA) and shield crossing tunnel from below (SCTB) are studied, respectively, based on field measurements and site investigations of actual projects in Shanghai soft ground. The risks of shield crossing sensitive buildings and subways, ground movement prediction and its control regulations, the settings of shield driving parameters such as earth pressure, driving speed, postures and grouting are demonstrated and summarized in detail. It is proposed that stringent stipulations on controlling ground volume loss (GVL) ratio (GVLR) and strengthened monitoring measures are necessary and substantial for eliminating/reducing potential construction risks. It is urgently decisive to improve the performance of shield machine and to make it more flexible for counteracting complications of geology and environment, as refer to the present status of shields in Shanghai, most of them being overused or out of date.     

价值最大化下裂解原料优化选择的探讨

广州石化在炼油改扩建投产后，裂解原料较为丰富，可选择范围广。通过对生产数据的统计分析，确定了原料优化的选择原则，取得了产值最大化的目标。     

Implications of sensor location in steam reformer temperature control

Hydrogen can be produced via steam reformation of many feedstocks. External heat sources provide the thermal energy required by the endothermic steam reformation reactions. Temperature control of the steam reformation reactor is critical to reactor performance and catalyst life. Closed-loop control systems are typically used to modulate the heat input rate based on a comparison between a set point temperature and a temperature measurement. The location of the temperature sensor relative to the heat input location is a choice made during reactor design that can have significant impact on reactor temperature control.     

Degradation behaviour of methamidophos and chlorpyrifos in apple juice treated with pulsed electric fields

Apple juice (13 °Brix) spiked with methamidophos and chlorpyrifos (2–3 mg/l of each compound) was treated by pulsed electric fields (PEF), and pesticide residues were quantified by gas chromatography with flame photometric detection (GC-FPD). Results showed that electric field strength (8–20 kV/cm) and pulse number (6–26 pulses) have significant effects on the degradation of methamidophos and chlorpyrifos. PEF treatment is effective for the degradation of methamidophos and chlorpyrifos residues in apple juice, and chlorpyrifos is much more labile to PEF than methamidophos. An increase in either pulse number or electric field strength could speed the degradation of methamidophos and chlorpyrifos, and the kinetics equations and related parameters quantitatively characterized the degradation behavior of the pesticides. The exponential model better fits the experimental data for all treatments than the linear model.     

Using TDR Cables and GPS for Landslide Monitoring in High Mountain Area

Time domain reflectometry (TDR) is performed as a complement to the monitoring methods in subsurface deformation in slope together with the global positioning system (GPS) to monitor ground deformation of high-altitude landslides in Li-shan. Four TDR cables were installed in drill holes near the monitoring stations in the landslide area. According to the recorded TDR waveforms, there were shear and tensile zones under the B-5, B-9, C-1, and C-2 stations. A comparison of the TDR waveforms with the monitored data and boring log revealed that the subsurface sliding occurred between layers of colluvium and strongly weathered slate. Three GPS receivers were installed to measure ground displacement in the landslide area. The results from the GPS were compared with the surface extensometers data on-site. The two initial baseline lengths were 451,188.10 and 908,212.4?mm, respectively. The optimal data reduction achieved used a 3?h session with moving average for each hour’s GPS data. The standard deviation values of the GPS were 2.16 and 2.44?mm, respectively, on-site. The results of TDR and GPS measurements showed their applicability in the deformation monitoring of high-mountain landslides.     

Do they see eye to eye? Management and employee perspectives of high-performance work systems and influence processes on service quality.

Extant research on high-performance work systems (HPWSs) has primarily examined the effects of HPWSs on establishment or firm-level performance from a management perspective in manufacturing settings. The current study extends this literature by differentiating management and employee perspectives of HPWSs and examining how the two perspectives relate to employee individual performance in the service context. Data collected in three phases from multiple sources involving 292 managers, 830 employees, and 1,772 customers of 91 bank branches revealed significant differences between management and employee perspectives of HPWSs. There were also significant differences in employee perspectives of HPWSs among employees of different employment statuses and among employees of the same status. Further, employee perspective of HPWSs was positively related to individual general service performance through the mediation of employee human capital and perceived organizational support and was positively related to individual knowledge-intensive service performance through the mediation of employee human capital and psychological empowerment. At the same time, management perspective of HPWSs was related to employee human capital and both types of service performance. Finally, a branch's overall knowledge-intensive service performance was positively associated with customer overall satisfaction with the branch's service. (PsycINFO Database Record (c) 2010 APA, all rights reserved)