干冰喷射技术在油罐清污中的应用

油罐内壁被油品严重污染,需要处理.介绍了干冰喷射清洗的机理及应用该技术彻底清除油污的情况,并对其应用优势进行了分析.     

冰蓄冷中央空调技术的应用

结合西北某机场制冷站工程,介绍了冰蓄冷中央空调技术的实际应用,分别阐述了冰蓄冷系统的工艺原理,结构组成及施工工艺,并通过经济性分析,总结了冰蓄冷中央空调技术的优点,指出该技术前景广阔,值得推广。     

Code performance with improved two-group interfacial area concentration correlation for one-dimensional forced convective two-phase flow simulation

In gas–liquid two-phase flow simulation for reactor safety analysis, interfacial momentum transfer in two-fluid model plays an important role in predicting void fraction. Depending on flow conditions, a shape of the two-phase interface complicatedly evolves. One of the proposed approaches is to quantify the gas–liquid interface information using interfacial area transport equation. On the other hand, a more simplified and robust approach is to classify bubbles into two-groups based on their transport characteristics and utilize constitutive equations for interfacial area concentration for each group. In this paper, interfacial drag model based on the two-group interfacial area concentration correlations is implemented into system analysis code, and void fractions were calculated for the evaluation of numerical behaviors. The present analysis includes (1) comparison of one-group and two-group relative velocity models, (2) comparison with separate effect test database, (3) uncertainty evaluation of drag coefficient, (4) numerical stability assessment in flow regime transition, and (5) transient analysis for simulating the prototypic condition. Results showed that utilization of interfacial drag force term using constitutive equations of two-group interfacial area concentration yields satisfactory void fraction calculation results. The proposed solution technique is practical and advantageous in view of reducing the computational cost and simplifying the solution scheme.     

EXPERIMENTS OF SEA ICE SIMULATION

As a substitute for the original displaced pole grids, a simple rotated spherical coordinate system was intro duced into the Community Sea Ice Model version 4（CSIM4）, which is a component of the Community Climate System Model（CCSM） of the American National Center of Atmospheric Researeh（NCAR）, to deal with the ＂pole problems＂. In the new coordinates, both the geographical North Pole and South Pole lie in the model equator and grid sizes near the polar region are more uniform. With reanalysis dataset of American National Centers for Environment Prediction （NCEP） and Levitus dataset without considering sub-mixed layer heat flux, the model was integrated for 100 years with thermodynamics proce.ss involved only in the former 49 years and both dynamic and thermodynamic processes involved in the left time. Inner consistency of model results was checked with no contradiction found. The results of last 10 years＇ model output were analyzed and it is shown that the simulated sea ice seasonal variation is rational whereas sea ice extent in the Barcnts Sea in winter is larger than that of observation, Numerical experiment on influence of sub-mixed layer heat flux was also carried out and it is shown that the sub-mixed layer heat flux can modulate seasonal variation of sea ice greatly. As a model component, the sea ice model with rotated spherical coordinates was coupled with other models （the oceanic general cir culation model is the LASG/IAP Climate System Ocean Model （LICOM） with reduced grid, other models are components of NCAR CCSM2） forming a climate system model and its preliminary results were also given briefly.     

Antifreeze Proteins: Novel Applications and Navigation towards Their Clinical Application in Cryobanking

Antifreeze proteins (AFPs) or thermal hysteresis (TH) proteins are biomolecular gifts of nature to sustain life in extremely cold environments. This family of peptides, glycopeptides and proteins produced by diverse organisms including bacteria, yeast, insects and fish act by non-colligatively depressing the freezing temperature of the water below its melting point in a process termed thermal hysteresis which is then responsible for ice crystal equilibrium and inhibition of ice recrystallisation; the major cause of cell dehydration, membrane rupture and subsequent cryodamage. Scientists on the other hand have been exploring various substances as cryoprotectants. Some of the cryoprotectants in use include trehalose, dimethyl sulfoxide (DMSO), ethylene glycol (EG), sucrose, propylene glycol (PG) and glycerol but their extensive application is limited mostly by toxicity, thus fueling the quest for better cryoprotectants. Hence, extracting or synthesizing antifreeze protein and testing their cryoprotective activity has become a popular topic among researchers. Research concerning AFPs encompasses lots of effort ranging from understanding their sources and mechanism of action, extraction and purification/synthesis to structural elucidation with the aim of achieving better outcomes in cryopreservation. This review explores the potential clinical application of AFPs in the cryopreservation of different cells, tissues and organs. Here, we discuss novel approaches, identify research gaps and propose future research directions in the application of AFPs based on recent studies with the aim of achieving successful clinical and commercial use of AFPs in the future.     

Conflict Urbanism,Aleppo: Mapping Urban Damage

One of the oldest continuously inhabited cities on the planet, Aleppo now lies in tatters. This devastation of a designated World Heritage Site is a poignant example of the human and cultural cost of armed conflict – in this case the Syrian Civil War. A project run by the Center for Spatial Research at the Graduate School of Architecture, Planning and Preservation of New York's Columbia University is analysing satellite imagery and reports from the ground to assess the damage and casualties caused there by barrel bombs. Associate Professor Laura Kurgan describes the initiative and its sometimes puzzling findings.     

Three-dimensional time-averaged void fraction distribution measurement technique for BWR thermal hydraulic conditions using an X-ray CT system

We have developed a void fraction distribution measurement technique using the three-dimensional (3D) time-averaged X-ray computed tomography (CT) system to understand two-phase flow behavior inside a fuel bundle for boiling water reactor (BWR) thermal hydraulic conditions of 7.2 MPa and 288 °C. As a first step, we measured the 3D void fraction distribution in a vertical square (5?×?5) rod array that simulated a BWR fuel bundle in the air–water test. A comparison of the volume-averaged void fractions evaluated by the developed X-ray CT system with those evaluated by a differential pressure transducer showed satisfactory agreement within a difference of 0.03. Thus, we confirmed that the developed system could be used to get 3D imaging of the vertical square rod array used in the test under the BWR operating pressure condition. In the next step, we did a verification test using the vertical pipe (11.3 mm ID) for BWR thermal hydraulic conditions. A comparison of the cross-sectional-averaged void fractions evaluated by the X-ray CT system with those evaluated by the drift-flux model showed good agreement within a difference of 0.05. We confirmed that the evaluated void fraction distribution forms in the horizontal cross section changed with the quality in response to the flow regime transition.     

Hydroxyl Group Separation Distances in Anti-Freeze Compounds and Their Effects on Ice Nucleation

Since the discovery of biological antifreeze glycoproteins (AFGPs), which can inhibit ice nucleation, there has been considerable interest in understanding their mechanisms and mimicking them in synthetic polymers. In this study, we used molecular dynamics simulations of modified polyvinyl alcohol (PVA) compounds to show that the hydroxyl (OH) group distance is a key factor in whether certain compounds promote or inhibit ice nucleation. A hydroxyl distance smaller than ~2.8 Å but greater than ~7.1 Å in modified PVA (MPVA) compounds was associated with the promotion of ice nucleation, while a hydroxyl group separation distance of approximately ~5.0 Å was correlated with a delay in ice nucleation, owing to changes in the energy of the system. Thus, these results may help explain some of the mechanisms of current known anti-freeze compounds and may have implications for designing new anti-freeze compounds in the future.     

酸奶冰淇淋的研制

研制以鲜奶为主要原料,先将其中一部分加入乳酸菌进行发酵,然后再和其它配料混合,按照常规冰淇淋加工工艺进行加工,研制出风味独特、酸甜适中,集酸奶和冰淇淋优点于一身,达到冰淇淋各项指标要求的酸奶冰淇淋。实验对酸奶添加量、添加剂的使用量、均质压力等工艺参数进行研究。     

南方地区电网覆冰事故分析及应对措施研究

根据2008年初中国南方地区电网遭受冰害事故统计和调研情况,从覆冰机理、电网设施本身出发,分析了造成这次大面积冰害事故的原因。将国内外有关输电线高度订正系数的算法进行了比较分析,并对高度、线径系数进行了细化以便实现较好的经济技术效应。结合本次电网冰害事故所反映出的问题,提出了输电线路覆冰事故防治措施。