微生物培养基的灭菌剂——β-丙酮内酯

为对微生物进行纯种培养,必须将其培育于没有杂菌的基质上。这种无菌基质可通过“热压”或“过滤”灭菌法制备。但以上二法均有一定的缺点。热压法通常是在加压及加温下进行,容导致培养基中某些热敏感成分的损失。据赫密尔发勃(P.Himmelfarb)等报告,0.1%葡萄糖溶液经121℃灭菌15分钟,竟降解了49.5%;并能引起不必要的物理变化,如增加色素等。当将含蛋白胨的基质在较高温度下灭菌后,会变成深红色,对发酵过程的考察有所影响。过滤法是将培养液通过过滤器灭菌,常用的如Seitz 滤器。此法仅适用于小量培养基的灭菌,而且部分营养成分常为过     

灭菌柜灭菌冷热点对灭菌有效性的影响

目的:保证灭菌工艺的有效性以及灭菌物品的安全性、完整性和稳定性,减少因灭菌点位不同造成的灭菌效果差异.方法:采用同一台脉动蒸汽灭菌柜对同一品种培养基灭菌,进行热穿透试验,利用温度验证仪(K仪)布点,对锅内进行全程温度监控,实时掌握各阶段温度状态及灭菌效果.结果:8次满载试验证明,灭菌过程中会因物品在锅内码放位置的不同而...     

湿热灭菌柜的性能验证

湿热灭菌柜是一种常见的消毒灭菌装置。该设备性能验证中,要选用合适的灭杀方法、选取适宜的灭菌阶段冷点,并保证空气过滤器的完整性和在线灭菌。     

无菌过滤方法的验证

验证是生产质量管理的核心。验证的内容包括生产方法、检验方法、设备、厂房设施以及一切原材物料。无菌过滤的验证具有特殊的重要意义。一些不适宜进行最后灭菌处理的溶液,无菌过滤就是一种常用的制备方法。无菌过滤的最大优点是既能保证产品的高度无菌,又能使产品不致受灭菌处理的分解。单独无菌过滤是没有实际意义的,经无菌过滤的溶液还必须在无菌条件下灌装,或在无菌条件下结晶,或在无菌条件下喷雾干     

5-羟甲基糠醛生成量与高压灭菌的关系

本文对葡萄糖注射液中5-羟甲基糠醛含量的检测中发现,其生成量与灭菌时间有关;与灭菌温度有关;与灭菌方法有关;与药液本身5-羟甲基糠醛的含量有关。     

门冬氨酸洛美沙星葡萄糖注射液处方工艺优化

为优化制备工艺,提高注射液的稳定性,采用正交设计法筛选门冬氨酸洛美沙星葡萄糖注射液制剂处方工艺。以门冬氨酸洛美沙星的含量和有关物质为考察指标,针对可能影响产品稳定性的因素开展实验研究。研究发现,最佳处方工艺是后加0.1%活性炭,以0.01%亚硫酸氢钠为稳定剂,采用115℃、灭菌30 min,并且灭菌后快速冷却至70℃以下。结果表明,优化后的处方工艺可明显提高制剂的稳定性。     

利巴韦林注射液处方工艺优化研究

通过对不同p H值条件下样品的有关物质、含量等质量情况的考察,确定了最佳p H值为5.2-5.4;通过对不同灭菌条件下样品有关物质、含量等质量情况的考察,确定了灭菌工艺为115℃×30min的湿热灭菌;通过对活性炭添加量的优化,确定了原料药100%理论标示量投料,活性炭加入质量与药液体积的比例为0.1%。优化后的处方工艺提高了利巴韦林注射液生产过程中的无菌保证能力,且随之使其生产方式由除菌过滤加无菌灌装转变为最终灭菌,降低了人员过程操作和生产环境控制的难度。     

吡拉西坦注射液的生产工艺研究

目的:研究吡拉西坦注射液的生产工艺。方法:对吡拉西坦注射液进行灭菌工艺研究,筛选并确定最佳工艺条件,并根据确定的工艺条件进行工艺验证。结果:吡拉西坦注射液采用湿热灭菌工艺,灭菌条件选择121℃灭菌12 min,F₀值≥12,制备的产品质量符合要求。结论:合理的制备工艺和条件,可以保证吡拉西坦注射液的质量。     

克林霉素磷酸酯注射液灭菌工艺研究

依照克林霉素磷酸酯注射液的质量标准要求,进一步研究克林霉素磷酸酯注射液生产工艺。配制不同p H值的克林霉素磷酸酯注射液,对其进行不同时间的灭菌试验,检测有关物质,筛选出适宜的p H值和灭菌时间。药品生产时采用无菌条件下的除菌过滤加100℃的辅助灭菌工艺,同时控制药液的p H值为6.1~6.3、灭菌时间不超过30min的生产方法,能较好的控制有关物质的升高,生产出质量更稳定,使用更安全的药品。     

呋塞米注射液的生产工艺研究

目的:研究呋塞米注射液的生产工艺。方法:对呋塞米注射液进行灭菌工艺研究,筛选并确定最佳工艺条件,并根据确定的工艺条件进行工艺验证。结果:呋塞米注射液采用湿热灭菌工艺,灭菌条件选择121℃灭菌15 min,F0值≥12,制备的产品质量符合要求。结论:合理的制备工艺和条件,可以保证呋塞米注射液的质量。     

Effects of heat and water transport on the performance of polymer electrolyte membrane fuel cell under high current density operation

Key challenges to the acceptance of polymer electrolyte membrane fuel cells (PEMFCs) for automobiles are the cost reduction and improvement in its power density for compactness. In order to get the solution, the further improvement in a fuel cell performance is required. In particular, under higher current density operation, water and heat transport in PEMFCs has considerable effects on the cell performance. In this study, the impact of heat and water transport on the cell performance under high current density was investigated by experimental evaluation of liquid water distribution and numerical validation. Liquid water distribution in MEA between rib and channel area is evaluated by neutron radiography. In order to neglect the effect of liquid water in gas channels and reactant species concentration distribution in the flow direction, the differential cell was used in this study. Experimental results suggested that liquid water under the channel was dramatically changed with rib/channel width. From the numerical study, it is found that the change of liquid water distribution was significantly affected by temperature distribution in MEA between rib and channel area. In addition, not only heat transport but also water transport through the membrane also significantly affected the cell performance under high current density operation.     

封堵高温裂隙的水泥基泡沫流体耐热性研究

煤岩体受热破坏形成的高温煤岩裂隙是煤田火区演化和蔓延的主要成因.水泥基泡沫流体作为一种新型的高温煤裂隙防控材料,其泡沫流体的耐热特性是其重要的技术参数.基于自制泡沫流体隔热性能测试系统,测试了不同支架高度(2 cm、7 cm、12 cm、17 cm、22 cm)和不同喷注厚度(20 mm、40 mm、60 mm、80 mm)情况下水泥基泡沫流体的隔热特性,得出随着测试时间的增加,20~80 mm各个喷注厚度的新鲜泡沫流体冷面温度都增加,在测试时间为0~90 s以内,温升曲线斜率较大;隔热温度空间分布整体在一个曲面上,进而拟合得到了隔热温度、喷注厚度、热面温度三者之间的关系式.受热情况下泡孔液膜微观形态变化表征显示泡沫流体在200 ℃出现失稳定,并从表面张力、液膜基质粘度、自由水含量三个方面分析了受热对液膜排液速度的影响.     

Effect of viscous dissipation on the temperature of the polymer during injection molding filling

During injection molding, viscous dissipation changes the temperature distribution by playing the role of an energy source, which affects heat transfer rates. Understanding the effect of the viscous dissipation assists the designing of the cooling system in injection molding process. In this article, the effect of the viscous dissipation on the temperature distribution throughout a rectangular channel for different polymers at different inlet velocities and temperatures is studied. A cross type rheological model depending on the temperature and pressure is assumed for polymer materials polystyrene (PS) and polypropylene (PP). The evolution of the flow velocity inside the channel is presented. The quantity of heat added due to viscous dissipation to the polymer is also calculated up to different positions through the channel. A numerical finite volume code for the simulation of polymer melt flow in a channel is used and a validation of this numerical code is presented. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.     

Continuous high-temperature/short-time sterilization of liquid foods with steam-injection heating

The continuous high-temperature/short-time sterilization of liquid foods is investigated. A steam-injection, which is frequently used in industrial sterilization processes, is considered. The non-Newtonian power-law model is employed to characterize the liquid food flow and an energy balance to calculate the temperature distribution in the cooling section. Well-established kinetics is adopted to model the microorganism (Cl. botulinum) destruction and nutrient (vitamin B₁₂) denaturation. The total length of sterilizer is determined for different sterility requirements, process temperatures and pseudoplastic indices.     

Numerical Investigation of the Heating Process of the Walls in Steam Sterilizers

The basic principle of steam sterilization is based on high heat transfer rates from the steam to the medical device. In order to carry out this process as well as possible, the walls of the pressure chamber must be preheated. One way is to heat it with steam from the inside. To investigate this process, a three-phase CFD model was developed, which can be used to determine the saturation temperature as a function of the partial pressure using a user-defined function. For validation, the pressure, temperature (fluid and solid) and condensate content were measured. Results show that the model is excellently suited for predicting all relevant variables.     

两种灭菌方式对医用级聚丙烯结构与性能的影响

将三种不同聚丙烯(PP-1、PP-2、PP-3)的注塑样条分别进行湿热灭菌和辐照灭菌处理,与未经灭菌的聚丙烯进行性能对比,了解灭菌处理后产品是否符合医用标准的要求,并探究产生差异的原因。结果表明:PP-1和PP-2中存在α晶型和γ晶型,PP-3只存在α晶型,两种灭菌方式均不会改变三种PP的晶型,经灭菌处理后PP的结晶度增大,拉伸强度、弯曲强度与弯曲模量增大,但冲击强度下降,PP-1和PP-2的力学性能可达到医用标准;紫外吸光度值可以评定材料中产生水溶性有机物的含量,通过测试紫外吸光度值发现,辐照灭菌后只有PP-1不符合医用安全标准。     

Elimination of biological fouling in seawater reverse osmosis desalination plants

The main trouble in the RO method of seawater desalination is biological fouling (bio-fouling) from microorganism growth. In this work, the growth rate of microorganisms in the Red Sea and sterilization by chlorine injection were measured and quantified. Furthermore, actual demonstration of RO pilot tests using cellulose tri-acetate (CTA) RO membranes with chlorine resistance was performed in RO plants where bio-fouling actually occurred. By carrying out direct chlorine sterilization of the RO membrane with an intermittent chlorine injection method, bio-fouling was eliminated. The combination of the CTA membrane and chlorine injection successfully prevented increases of differential pressure and stabilized product water quantity and quality.     

Three-dimensional numerical modelling of interactions between a gas–liquid jet and a fluidized bed

This paper presents the development of a novel mathematical model that describes spray injection and spreading into a fluidized bed of solid particles. The model also includes the gas–liquid flow through the nozzle followed by the gas-assisted atomization. An Eulerian approach that is independent of the nature of the continuous phase is adopted for all phases, which are gas (or bubbles), liquid (or droplets), and solid particles that may be covered with a liquid layer. Variation in sizes of bubbles and droplets is represented by the particle number density approach that takes into account both break-up and coalescence. The atomization is considered as a catastrophic phase inversion triggered by a critical local volume fraction. New relationships were obtained for liquid spreading due to wet particle collisions and for heat conduction between a solid particle and a surrounding liquid layer. The model is applied to simulate liquid injection into the fluidized bed for conditions that were previously experimentally studied and published. The comparison reveals a reasonable agreement in prediction of the cumulative liquid distribution for two experimental cases. In addition, we evaluated a jet penetration distance with the model to compare it with the one measured in another set of experiments. This comparison also yields a good qualitative agreement. Finally, we evaluated the influence of the fluidization velocity on liquid distribution in the bed.     

影响水平管降膜蒸发传热性能的因素

影响水平管降膜蒸发传热性能的因素齐和发，沈吟秋（大连理工大学化工学院）关键词水平管降膜；传热膜系数；浓度１引言水平管降膜蒸发器是二十余年发展起来的一种高效节能型蒸发器。目前，这种蒸发器已广泛应用于海水淡化、医药、食品、化工和致冷等工业中［１］。影响水...