The control of paracetamol particle size and surface morphology through crystallisation in a spray dryer

The parameters governing the crystallisation of paracetamol using various conventional techniques has been extensively studied, however the factors influencing the drug crystallisation using spray drying is not as well understood. The aim of this work was to investigate the crystallisation of an active pharmaceutical ingredient through evaporative crystallisation using a spray dryer to study the physicochemical properties of the drug and to use semi-empirical equations to gain insight into the morphology and particle size of the dried powder. Paracetamol solutions were spray dried at various inlet temperatures ranging from 60 °C to 120 °C and also from a series of inlet feed solvent compositions ranging from 50/50% v/v ethanol/water to 100% ethanol and solid-state characterisation was done. The size and morphology of the dried materials were altered with a change in spray drying parameters, with an increase in inlet temperature leading to an increase in particle Sauter mean diameter (from 3.0 to 4.4 µm) and a decrease in the particle size with an increase in ethanol concentration in the feed (from 4.6 to 4.4 µm) as a result of changes in particle density and atomised droplet size. The morphology of the dried particles consisted of agglomerates of individual crystallites bound together into larger semi-spherical agglomerates with a higher tendency for particles having crystalline ridges to form at higher ethanol concentrations of the feed.     

高准确度静态质量法液体流量标准装置及其不确定度评价

本文介绍了一种高准确度质量法液体流量标准装置的设计方法,为对市场中出现的高准确度科里奥利质量流量计的量值传递提供了可能。文中介绍了装置设计过程中,为提高装置准确度用到的电动换向、衡器自校准、蒸馏水代替自来水等方法。试验证明,上述方法的应用使装置达到了预期的不确定度水平。文章还着重介绍了高准确度静态质量法液体流量标准装置不确定度的评价要点,对装置的不确定度水平进行了评定。     

液晶显示技术的进展

通过实地考察,介绍美国、日本和欧洲的液晶显示技术,着重叙述有源矩阵液晶显示技术、制备关键工艺、新型液晶显示器件的开发以及夏普公司在LCD领域中的领先水平.     

浅议工程机械液压系统的使用与维护

分析了常用工程机械液压系统维护不当而对其造成的危害，探讨了如何正确使用与维护液压系统，以保证工程机械液压系统正常良好的技术状况，有效延长机械使用寿命。     

使用液氮回收LNG加气站BOG的可行性分析

介绍常用的LNG加气站BOG回收方法及BOG排放量计算,探讨使用液氮回收LNG加气站内BOG的工艺流程和液氮量计算。将使用液氮回收BOG与常用的BOG回收方法进行对比,分析使用液氮回收BOG的优势。     

振动管式液体密度传感器数学模型研究

本文介绍了振动管式液体密度计的数学模型,推导了其在出厂标定与发生系统漂移后一对重要参数的比例关系,优化了被测液体密度与振动管谐振周期的对应关系,结果证明,本方法所得曲线不仅拟合精确,还能有效消除系统漂移对测量结果带来的影响.     

驱水型挡风玻璃清洗剂的研制

采用乙醇、水、抗菌剂、驱水剂等添加剂进行复配,研制出具有较好驱水效果的挡风玻璃清洗剂。该清洗剂p H值接近中性,具有较好的驱水性能、清洗能力、橡胶相容性、树脂相容性和抑制金属腐蚀性能,适用于汽车挡风玻璃、反光镜、车窗玻璃的清洗,驱水效果明显。     

Structural and ion transport properties of [(AgI)x(AgBr)0.4−x](LiPO3)0.6 and (AgBr)x(LiPO3)(1−x) solid electrolytes

The (AgBr)_x(LiPO₃)_(1−x) (x=0.4 and 0.5) and [(AgI)_x(AgBr)_0.4−x](LiPO₃)_0.6 (x=0.1, 0.2, and 0.3) superionic electrolytes have been prepared by conventional melt quenching using a twin roller. These electrolytes are characterized by X-ray diffraction, SEM, and energy dispersive X-ray analysis (EDAX) for structural investigation. Electrical characterizations have been carried out by the AC impedance analysis. The conductivity of LiPO₃ glassy system at room temperature is improved by doping with the silver bromide (AgBr)_x(LiPO₃)_(1−x) and the mixture of silver iodide, silver bromide (AgI-AgBr-LiPO₃ system) up to 10⁻⁵ and 10⁻³ Ω⁻¹ cm⁻¹, respectively (improvements by four or five orders of magnitude). The frequency response of ionic conductivity has been analyzed by universal dynamic response model (Jonscher's law) and AC conductivity data are fitted using the Jonscher's power law. The conductivity values obtained by the power law and impedance plots are comparable. The frequency exponent (n) has a value between 0 and 1. The AgI-AgBr-LiPO₃ system shows the mixed alkali effect. Summerfield scaling master curve is temperature dependent, which may be due to the contribution of the both lithium and silver ions to ionic conduction.     

Rapid Carbonation for Calcite from a Solid-Liquid-Gas System with an Imidazolium-Based Ionic Liquid

Aqueous carbonation of Ca(OH)₂ is a complex process that produces calcite with scalenohedral calcite phases and characterized by inadequate carbonate species for effective carbonation due to the poor dissolution of CO₂ in water. Consequently, we report a solid-liquid-gas carbonation system with an ionic liquid (IL), 1-butyl-3-methylimidazolium bromide, in view of enhancing the reaction of CO₂ with Ca(OH)₂. The use of the IL increased the solubility of CO₂ in the aqueous environment and enhanced the transport of the reactive species (Ca²⁺ and CO₃²⁻) and products. The presence of the IL also avoided the formation of the CaCO₃ protective and passivation layer and ensured high carbonation yields, as well as the production of stoichiometric rhombohedral calcite phases in a short time.     

20英尺低温液体罐式集装箱的结构强度计算

根据《集装箱检验规范》(中国船级社)和IMDG CODE《国际海运危险货物规则》中的有关要求,进行了20英尺低温液体罐式集装箱的结构强度计算,分析时选取了板壳单元和梁单元,4个箱角刚性固定,将各个运动方向上的惯性力转化为动压力叠加到设计压力上,分别进行计算,计算结果满足规范要求。