Effect of cooling technique on physicochemical properties of ternary solid dispersion of manidipine hydrochloride prepared by melting method

Solid dispersion is an established concept for drug solubility and bioavailability enhancement but strongly dependent on the choice of an appropriate carrier and preparation technique[1,2].Ternary solid dispersion is one of the promising methods to increase the solubility of poorly-water soluble drug.The present work was conducted to increase the solubility of manidipine hydrochloride(MDP)using ternary solid dispersion prepared by melting and then solidifying at low temperature.The effect of cooling technique on the physicochemical properties of the developed system was investigated.

Kinetic parameter estimation for cooling crystallization process based on cell average technique and automatic differentiation

In this paper,a cell average technique(CAT)based parameter estimation method is proposed for cooling crystallization involved with particle growth,aggregation and breakage,by establishing a more efficient and accurate solution in terms of the automatic differentiation(AD)algorithm.To overcome the deficiency of CAT that demands high computation cost for implementation,a set of ordinary differential equations(ODEs)entailed from CAT based discretized population balance equation(PBE)are solved by using the AD based high-order Taylor expansion.Moreover,an AD based trust-region reflective(TRR)algorithm and another interior-point(IP)algorithm are established for estimating the kinetic parameters associated with particle growth,aggregation and breakage.As a result,the estimation accuracy can be further improved while the computation cost can be significantly reduced,compared to the existing algorithms.Benchmark examples from the literature are used to illustrate the accuracy and efficiency of the AD-based CAT,TRR and IP algorithms in comparison with the existing algorithms.Moreover,seeded batch cooling crystallization experiments ofβform L-glutamic acid are performed to validate the proposed method.

Case-Based Reasoning(CBR) Model for Ultra-Fast Cooling in Plate Mill

New generation thermo-mechanical control process（TMCP） based on ultra-fast cooling is being widely adopted in plate mill to product high-performance steel material at low cost. Ultra-fast cooling system is complex because of optimizing the temperature control error generated by heat transfer mathematical model and process parameters. In order to simplify the system and improve the temperature control precision in ultra-fast cooling process, several existing models of case-based reasoning（CBR） model are reviewed. Combining with ultra-fast cooling process, a developed R5 CBR model is proposed, which mainly improves the case representation, similarity relation and retrieval module. Certainty factor is defined in semantics memory unit of plate case which provides not only internal data reliability but also product performance reliability. Similarity relation is improved by defined power index similarity membership function. Retrieval process is simplified and retrieval efficiency is improved apparently by windmill retrieval algorithm. The proposed CBR model is used for predicting the case of cooling strategy and its capability is superior to traditional process model. In order to perform comprehensive investigations on ultra-fast cooling process, different steel plates are considered for the experiment. The validation experiment and industrial production of proposed CBR model are carried out, which demonstrated that finish cooling temperature（FCT） error is controlled within±25℃ and quality rate of product is more than 97%. The proposed CBR model can simplify ultra-fast cooling system and give quality performance for steel product.

Safety and efficacy of microwave ablation for periductal hepatocellular carcinoma with intraductal cooling of the central bile ducts through a percutaneous transhepatic cholangial drainage tube

Background and aims:Biliary thermal injury caused by microwave ablation(MWA)for a hepatocellular carcinoma(HCC)close to the central bile ducts always results in severe complications and leads to mortality.Some studies have demonstrated that intraductal cooling of the biliary tract with chilled saline during thermal ablation can successfully prevent these complications.In this study,we present a novel bile duct cooling technique through a percutaneous transhepatic cholangial drainage(PTCD)tube for preventing biliary thermal injury caused by MWA,and compare the feasibility and safety of the intraductal cooling technique when performed with a PTCD tube and with an endoscopic nasobiliary drainage(ENBD)tube.Methods:Participants were randomly assigned to undergo MWA of HCC with intraductal chilled saline perfusion through a PTCD tube or an ENBD tube.The main study outcomes were bile duct complications related to MWA and local tumor recurrence,p value<0.05 was considered to indicate a statistically significant difference.Results:A total of 23 patients with an HCC(23 nodules)close to a central bile duct were enrolled in this study.Of these patients,12 had a PTCD tube and 11 had an ENBD tube placed into the hepatic duct close to the lesions.There were no PTCD-and ENBD-related mortality cases.There was no complication related to the PTCD procedure;however,3 patients(27.27%)developed acute pancreatitis and 1 patient(9.09%)had hemorrhage in the ENBD group(p=0.037).One patient(8.33%)in the PTCD group had bile leakage and 2 patients(18.18%)in the ENBD group developed a biloma.Within 5 years,1 patient in the PTCD group and 2 patients in the ENBD group had local recurrence.There was no significant difference in local recurrence,nonlocal hepatic recurrence,mortality rate,or median cumulative overall survival between the 2 groups.Conclusions:The intraductal cooling technique using a PTCD tube is a feasible and effective method for preventing bile duct thermal injury caused by MWA for an HCC close to the central bile ducts.It does not increase local recurrence and may be safer than intraductal cooling through an ENBD tube.

Microstructure and Mechanical Properties of Nb-B bearing Low Carbon Steel Plate: Ultrafast Cooling versus Accelerated Cooling

The microstructure and mechanical properties of low carbon bainite high strength steel plate were studied via different cooling paths at the pilot scale. There was a significant increase in mechanical properties, and notably, the yield strength, tensile strength, and toughness at-40 ℃ for the tested steel processed by ultra-fast cooling were 126 MPa, 98 MPa and 69 J, respectively, in relation to steel processed by accelerated cooling. The ultra-fast cooling rate not only refined the microstructure, precipitates, and martensiteaustenite（M/A） islands, but also contributed to the refinement of microstructure in thick plates. The large size M/A constituents formed at lower cooling rate experienced stress concentration and were potential sites for crack initiation, which led to deterioration of low-temperature impact toughness. In contrast, the acicular ferrite and lath bainite with high fraction of high-angle grain boundaries were formed in steel processed by ultra-fast cooling, which retarded cleavage crack propagation.

Mechanism Interpretation of the Biological Brain Cooling and Its Inspiration on Bionic Engineering

The brain is one of the most important organs in a biological body which can only work in a relatively stable temperature range. However, many environmental factors in biosphere would cause cerebral temperature fluctuations. To sustain and regulate the brain temperature, many mechanisms of biological brain cooling have been evolved, including Selective Brain Cooling （SBC）, cooling through surface water evaporation, respiration, behavior response and using special anatomical ap- pendages. This article is dedicated to present a summarization and systematic interpretation on brain cooling strategies devel- oped in animals by classifying and comparatively analyzing each typical biological brain cooling mechanism from the per- spective of bio-heat transfer. Meanwhile, inspirations from such cooling in nature were proposed for developing advanced bionic engineering technologies especially with two focuses on therapeutic hypothermia and computer chip cooling areas. It is expected that many innovations can be achieved along this way to find out new cooling methodologies for a wide variety of industrial applications which will be highly efficient, energy saving, flexible or even intelligent.

Nozzle Spray Diffusivity Changing Law for Ultra Fast Cooling in Hot Strip Mill

Slot nozzle and intensive nozzle can be used in ultra fast cooling equipment. The spray cooling method with higher water pressure can be taken in order to achieve ultra fast cooling for hot rolled strip. Water will be diffused after it is sprayed out from ultra fast cooling nozzle. Spray diffusivity will affect water velocity and penetrability of water into residual water layer on top of the strip,and then it will affect strip cooling effect. Water spraying process can be simulated by Fluent and some conclusions were obtained. Slot nozzle width and outlet velocity within setting range could not affect the length of potential core zone and the spray diffusivity. Intensive nozzle diameter and outlet velocity will affect the length of potential core zone and the spray diffusivity with different extent. These conclusions will provide referenced role for confirming ultra fast cooling nozzle size and distance between ultra fast cooling nozzle and hot rolled strip.

Experimental Investigation of the Cooling Capacity of Gaseous Carbon Dioxide in Free Jet Expansion for Use in Portable Air-Cooling Systems

This paper investigates the possibility of using the free expansion of gaseous CO2 in portable air-cooling systems. The cooling capacity of the gaseous CO2 free jet expansion was calculated using three different approaches and the results showed that the simplified calculations would give approximated cooling values with an 11.6% maximum error. The mass flow rate, upstream pressure and cooling capacity of the gaseous CO2 decreased with time. A maximum 48.5 watts of cooling was recorded at minute 4 and a minimum value of 10.4 watts at the end of the test. The drop in cooling capacity is due to the evaporation of the liquid CO2 inside the small cylinder which cools the two-phase CO2 mixture and causes a pressure drop (from 6 MPa to 2.97 MPa), which also affects the mass flow rate of gaseous CO2 exiting the orifice (from 0.56 g/s to 0.24 g/s). If this cooling technique is to be considered in portable compact-cooling systems, the mass, pressure and cooling capacity drop with time must be solved. One of the solutions could be to cover the cylinder with a heating coat to compensate for the heat absorbed by the evaporation of the liquid CO2.

基于DIC及CPG技术的热冷循环后花岗岩Ⅰ型断裂特性

深部储层岩石的热力学特性,尤其是循环热冷作用下损伤破坏特性,对于增强型地热系统井壁稳定性分析及地热开采效率评估具有重要意义。针对中心直裂纹半圆盘(NSCB)花岗岩试样,首先进行不同热冷循环处理(加热温度400℃,最高循环次数13次),然后开展3点弯Ⅰ型断裂韧度特性试验。基于裂纹扩展计(CPG)和数字图像相关(DIC)测试技术,研究了热冷循环作用下花岗岩Ⅰ型断裂韧度、断裂过程区(FPZ)、裂纹扩展速率及断裂轮廓特征的影响规律。试验结果表明:当热冷循环次数达到10次以上,花岗岩试样脆性明显减弱,而峰前软化特性和峰后延性增强;花岗岩的断裂过程区由裂缝尖端开始逐步孕育,断裂过程区长度随荷载增大呈先增大后减小的趋势,Ⅰ型断裂韧度、最大断裂过程区长度及裂纹平均扩展速度随热冷循环次数增大而指数减小,Ⅰ型断裂面随热冷循环次数增大越来越不平整。最后,基于X-ray衍射(XRD)和扫描电镜(SEM)等微观测试技术,研究了热冷循环作用对花岗岩矿物成分及微观结构的影响规律,结果表明花岗岩4种矿物成分的峰值衍射强度及矿物质量分数均随热冷循环次数增大而降低,而微裂纹大小及数量随热冷循环次数增大而增大。热冷循环作用下花岗岩的损伤劣化机理包含了多次高温热损伤、水冷冲击及水弱化等3方面的联合作用结果。

泰顺三杯香绿茶加工关键技术研究

为了提高三杯香绿茶产品竞争力,规范茶叶加工,研究通过对泰顺三杯香绿茶传统工艺的调研,结合当前市场对于绿茶品质风味的需求,从冷却回潮、揉捻、滚炒提香三个工序进行试验改进,通过感官审评进行比较研究,优化了当前三杯香绿茶加工工艺及参数,提高了三杯香绿茶的干茶绿度、成条率及香气品质。研究旨在规范三杯香绿茶加工,提高产品市场竞争力。

基于光纤复合测量技术的涡轮叶片气膜孔检测

为了解决航空发动机涡轮叶片气膜孔几何特征参数有效检测手段缺乏、测量结果一致性差的问题,设计并搭建了基于光纤复合测量技术的涡轮叶片气膜孔检测系统,提出了利用该系统对涡轮叶片气膜孔进行测量的方法,通过试验进行了方法验证。搭建的系统为多传感器测量系统,具备叶片接触与非接触测量、空间姿态定位及3D投影能力,实现了涡轮叶片全范围气模孔的测量。在试验中,选取高压涡轮叶片作为被测物体,应用该测量系统对叶片上的气膜孔进行了测量,计算得到了气膜孔直径、轴线角度及位置度的准确信息。结果表明:通过测量不确定度的分析评定可知,该系统对气膜孔直径、位置度的测量不确定度均小于0.01 mm,完全满足设计公差对测量仪器的精度要求,可以用于涡轮叶片气膜孔工程化测量。

动力电池直冷板漏率转化及测试方法

文章研究了动力电池直冷板制冷剂液态工质漏率到检漏气体气密检测漏率的转化关系,通过对直冷板泄漏的机理研究,推导出漏率转化公式,并与试验数据进行了对比。研究结果表明,直冷板在2 MPa、20℃的使用工况下,根据提出的理论计算公式可知,氦气检测时的泄漏值为1.504×10^(-5) Pa•m^(3)/s,试验直冷板的泄漏值在10-5 Pa•m^(3)/s量级,与理论计算结果非常接近,证明该公式能有效地计算直冷板漏率,可以指导工业应用。

Studying the Role Played by Evaporative Cooler on the Performance of GE Gas Turbine Existed in Shuaiba North Electric Generator Power Plant

It’s well known that the performance of a gas turbine (efficiency, heat rate and power generated) is largely dependent on mass flow rate of air, inlet air temperature and turbine inlet temperature (TIT). As turbine inlet temperature is dependent on quantity of burned fuel so that this factor is dropped out from this paper. It’s also known that gas turbines are constant volume machines i.e. at a given shaft speed they always move the same volume of air, but the power out-put of a turbine depends on the flow of mass through it. This is precisely the reason why on hot days, when air is less dense, power output falls off. A rise of one degree Centigrade temperature of inlet air decreases the power output by 1% and at the same time heat rate of the turbine also goes up. This is a matter of great concern to power producers. Many techniques have been developed to cool the inlet air to gas turbine. Some of these techniques to decrease the inlet air temperature are discussed here. The evaporative cooling technique is taken as a case study in this paper. A comparative studying is carried out between a unit using this technique and the same unit when the evaporative cooler is idle. The results advert to an increase in power output by 11.07% and a decrease in heat rate by approximately 4% when inlet air temperature drops from 50°C to 26°C.

含蜡原油及其乳状液体系微观结构观测的新方法

基于流变-原位显微同步测量技术和改进的复合型光源,构建了对含蜡原油及其乳状液体系微观结构观测的新方法。实际观测结果表明:新构建的显微观测方法观测到的蜡晶数量比偏光显微镜观测到的蜡晶数量高出70%,并且在识别微小尺寸蜡晶方面具有更高精度,与常规偏光显微观测结果相比,识别出的1~3μm范围内的蜡晶数量要多150%,刻画的1~2μm范围内蜡晶分形维数要高15%,使得新构建的显微观测方法对恶化初始冷却温度下形成的致密型蜡晶具有更为突出的观测优势。此外,新观测方法识别出的恶化和较优初冷温度下的蜡晶边缘间距差值更大,约是常规显微观测结果的2倍,更能体现出不同初冷温度下的蜡晶结构差异,与原油流变性的关联性也更显著。动态剪切条件下的蜡晶微观形貌受流场影响显著,随剪切速率增大,蜡晶形态和排列与流场的协同性增强。相比于离线观测,原位显微观测获得的蜡晶微观形貌与原油流变性的关联性更显著,更有利于从微观尺度阐释含蜡原油的流变性机制。新观测方法可以实现对原油乳状液中蜡晶和乳化水滴的同时观测,在识别两者相互作用和形成聚集结构方面具有更好的识别质量。

基于联合冷却计算模型的9HA.02燃气轮机冷却空气量预测及参数分析

采用集成零维半经验模型和准一维模型的联合冷却计算模型对GE公司最新型的9HA.02燃气轮机透平一级静叶进行计算,并回带到准一维模型中进行验证和关键参数校核,以减少经验参数选取带来的不确定性。然后进行参数分析,获得9HA.02燃气轮机的冷却技术水平参数Z和叶片统一温度Tbu以及给定主燃气入口温度条件下单个叶片排的冷却空气量的取值,并与计算得到的PG9351FA燃气轮机的冷却参数进行对比。由于9HA.02燃气轮机透平一级静叶采用新型定向凝固单晶合金材料,推算得到透平一级静叶和冷却透平段叶片最高容许温度差值达200℃,一级静叶的叶片最高容许温度为1090℃,相比于F级燃气轮机大幅提高。计算结果表明,H级燃气轮机冷却技术水平较F级燃气轮机明显提升;9HA.02燃气轮机透平的一级静叶冷却空气约占总冷却空气的1/4,明显低于F级燃气轮机的1/3。

不同冷却方式对激光加工CFRP的影响研究

为了探索不同冷却方式对激光加工的影响,采用水、气体以及水气复合3种不同冷却方式辅助激光加工碳纤维复合材料进行了对比研究,同时采用单因素实验研究了不同工艺条件对加工质量的影响,并分析了作用机理。结果表明,在3种冷却方式下,热影响区、槽深均随着功率、频率的降低而降低,随着扫描速率的增加而降低;在相同工艺参数下,水气复合辅助激光加工产生的热影响区最小,气体辅助激光加工产生的热影响区次之,水辅助激光加工产生的热影响区最大;当激光功率为2250 W、频率为1200 Hz、速率为120 mm/s时,水、气体以及水气复合3种不同冷却方式的热影响区分别为378μm,283μm,196μm,槽深分别为401μm,789μm,647μm;采用水气复合辅助激光加工可以在加工过程中实现较好的冷热平衡,获得最好的加工质量。该研究为更好地实现碳纤维复合材料低损伤加工提供了参考。

Effect of Ultra-Fast Cooling on Microstructure of Large Section Bars of Bearing Steel

The ultra-fast cooling technology of large section bars and the microstrueture for different cooling patterns were studied by optical microscope, transmission electron microscope and energy spectrometer. The results indicated that the large section bars were passed through the zone of secondary carbide precipitation quickly by ultra-fast cooling technology （UFC） at instantaneous cooling rate of about 200 ℃/s and the finishing cooling temperature was higher than Ms. The lamellar spacing of pearlite decreased and the microhardness increased with decreasing the rereddening temperature. The precipitation of network carbide was restrained when re-reddening temperature was 690 ℃. And fine laminated pearlite was obtained through transformation of pseudopearlition that induced the reduction of the diameter of pearlite grain and refinement of the lamellar spacing of pearlite, so ideal microstructures of promoting spheroidizing annealing were obtained.

Hot Rolled Strip Re-reddening Temperature Changing Law during Ultra-fast Cooling

Temperature deviation between surface and the center of hot rolled strip is formed during ultra-fast cooling （UFC）. Surface temperature would rise when temperature deviation goes up to an extent, and strip re-reddening phenomenon will appear. Strip re-reddening affects the stability of strip microstructure, property and temperature control precision. Thus, it is necessary to conduct research on re-reddening temperature changing law to improve strip property and temperature control precision. Strip temperature trends for various strip thicknesses and ultra-fast cooling rates were obtained by numerical calculation method. Re-reddening temperature, temperature deviation between surface and center, and boundary layer position changing law were obtained. By comparison, some conclusions were obtained： UFC re-reddening temperature and laminar cooling （LC） re-reddening temperature were linear to ultra-fast cooling rate respectively. Ultra-fast cooling rate affected UFC re-reddening temperature greatly, but it had little effect on LC re-reddening temperature. Equations which were used to calculate UFC re-reddening temperature, LC re-reddening temperature and maximum temperature deviation were obtained. The position of boundary layer stayed in 1/4 strip thickness.

变压器风冷控制系统时间继电器的设计

变电站中的风冷控制系统对变压器的散热至关重要,风机的启停依据变压器的运行温度与设定的时间间隔。以单片机为主控器设计了一种智能时间继电器,具有四种工作模式,每种工作模式的延时范围可在一定范围内任意调节,经Proteus仿真验证,该系统运行可靠,具有一定的应用价值。

CPU散热技术的最新研究进展

随着芯片集成度的不断提高,为CPU提供有效的散热方案成为电子行业的重要研究课题.针对CPU热障问题,着重讨论了热管、微通道和制冷芯片3种新型微冷却方式的发展现状、传热原理以及应用前景,分析了它们各自的优缺点和有待解决的问题,并对这一领域的发展前景作了展望.