Numerical Analysis of Refrigerant/Oil Mixture in a Vertical U-tube

EES software was used to simulate the flow of refrigerant and oil in underground U-tube of the Direct Expansion Ground Source Heat Pump. The results show that: the pressure of refrigerant/oil mixture first increases and then decreases along the U-tube;the temperature of refrigerant/oil mixture increases firstly and then decreases, in superheat region, the temperature rises sharply; the refrigerant/oil mixture exits in U-tube mainly as annular flow; the minimum refrigerant/oil return velocity is increasing when the U-tube diameter increases; comparing the simulation results with the experimental results find that the oil in the U-tube of the experimental system can return normally

Combination of nitrogen and organic fertilizers reduce N2O emissions while increasing winter wheat grain yields and quality in China

Wheat grain yields, quality, and nitrous oxide (N2O) emissions were controlled through the type and application rate of nitrogen (N) fertilizer. Here, we investigated the optimal management of N fertilization by examining the combined effects of organic and N fertilizers on wheat yields, quality, and N2O emissions. Field trials under six treatments were located on campus farms at Anhui Science and Technology University, including farmer’s common practice (270 kg N ha-1, N270), 2/3 reduction in N270 (90 kg N ha-1, N90), organic fertilizer with equal N270 (OF270), 2/3 reduction in OF270 (OF90), 4/5 reduction OF270 + 1/5 reduction N270 (20% OF270 + 80% N270), and 4/5 reduction OF90 + 1/5 reduction N90 (20% OF90 + 80% N90) were applied to winter wheat. The plots were arranged in a randomized complete block experimental design. The N2O emissions were quantified under different fertilization measures in the peak wheat growing season during sowing, jointing, and grain filling stages, respectively. Compared with N270 and N90 treatments, N2O emissions were significantly decreased by 18.6% and 27.2%, respectively, under 20% OF270 + 80% N270% and 20% OF90 + 80% N90 (p < 0.05). Further, N2O emissions in N270 were increased by 50.8% relative to N90. Wheat yields increased significantly under 20% OF90 + 80% N90 by 27.6% (N270) and 16.4% (N90), and were considerably enhanced under 20% OF270 + 80% N270 by 40.6% (N270) and 12.7% (N90) in contrast to OF270 and N270 (p < 0.05). Compared with N90, the content of wet gluten, protein and starch under 20% OF90 + 80% N90 treatment significantly increased by 7.7%, 13.8% and 7.9%, and enhanced by 7.6%, 4.8%, 8.0% relative to OF90, respectively (p < 0.05). The starch content increased significantly by 2.0%, whereas the settlement value decreased considerably by 2.9% under 20% OF270 + 80% N270 (p < 0.05), and there was no notable difference in the wet gluten and protein contents (p > 0.05). Our findings indicated that organic fertilizer mixed with N fertilizer can effectively reduce N2O emissions, increase both the grain yields and quality in wheat field compared with N fertilizer alone

Magnetic Properties of Oxygen-doping Fe-Co-based Nanocrystalline Alloy Films for High Frequency Application

Conference Name:IUMRS International Conference in Asia (ICA). Conference Address: Taipei, TAIWAN. Time:SEP 19-22, 2011.The effects of the introduction of oxygen were studied on the Fe62Co32Cr6-O alloy films synthesized by magnetron co-sputtering. The as-deposited films exhibited a high saturation magnetization and a suitable in-plane uniaxial anisotropy field at an optimized condition of an oxygen gas flow ratio of 1.3%. Also, a high real permeability of similar to 200 at frequency up to 3.3 GHz was obtained from the microwave permeability measurement at the optimized condition above. The combination of high saturation magnetization, adjustable in-plane uniaxial magnetic anisotropy field, and high resistivity makes the Fe62Co32Cr6-O films become a promising candidate for the high-frequency applications. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of MRS-Taiwa

Improvement in oil resistance of room temperature-vulcanized polysiloxane rubber via blending with self-synthetic fluorosilicone

In this work, different contents of vinyl-terminated fluorosilicone oil (VFS oil) were blended with room temperature-vulcanized (RTV) polydimethylsiloxane (PDMS). Via rheological detection, the addition of VFS oil could increase the viscosities of VFS/PDMS/silicon dioxide (SiO2) blends, probably due to the interaction between incorporated fluorine atom and silanol on the surfaces of SiO2. The additional “structuring effect” was reduced by enhancing the shearing rate of the mixed gums containing VFS oil and the obvious shear-thinning property was helpful for enhancing the processability. The curing process and cross-linking degree test of VFS/PDMS/SiO2 blends suggested that the VFS oil could reduce the curing time and the induction time, but did not play a positive role in the cure depth using a platinum catalyst. Mechanical property tests showed that the VFS oil did not increase the tensile strength and elongation at break, and the hardness slightly decreased with increasing VFS oil content. The oil resistance property test showed that the oil resistance of the polysiloxane rubber was well improved by the incorporation of the VFS oil containing the functional group –CH2CH2CF3. </jats:p