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.     

Nb5+掺杂对(Ca0.97Ba0.03)Cu3Ti4O12陶瓷结构与电性能的影响

该文利用固相反应法制备了(Ca0.97Ba0.03)Cu3Ti4-xNbxO12 (x=0,0.01,0.03,0.05,0.07,0.10,0.15,0.20， 摩尔分数)陶瓷。借助X线衍射仪及扫描电子显微镜研究了Nb5+的摩尔分数对(Ca0.97Ba0.03)Cu3Ti4O12陶瓷的相结构及表面微观形貌的影响，借助高低温介电测试系统和阻抗测试仪获得了(Ca0.97Ba0.03)Cu3Ti4-xNbxO12陶瓷电性能变化规律。结果表明，各组分(Ca0.97Ba0.03)Cu3Ti4-xNbxO12陶瓷均为单相立方钙钛矿结构；Nb5+摩尔分数的增加可抑制(Ca0.97Ba0.03)Cu3Ti4-xNbxO12陶瓷晶粒的生长并消除其晶粒异常长大；适量掺杂 Nb+能够有效提高(Ca0.97Ba0.03)Cu3Ti4-xNbxO12陶瓷的晶界电阻，从而降低其介电损耗，且可提高(Ca0.97Ba0.03)Cu3Ti4-xNbxO12陶瓷相对介电常数的温度稳定性。     

Deciphering the Origins of P1-Induced Power Losses in Cu(Inx,Ga1–x)Se2 (CIGS) Modules Through Hyperspectral Luminescence

In this report, we show that hyperspectral high-resolution photoluminescence mapping is a powerful tool for the selection and optimization of the laser ablation processes used for the patterning interconnections of subcells on Cu(In_x,Ga_1−x)Se₂ (CIGS) modules. In this way, we show that in-depth monitoring of material degradation in the vicinity of the ablation region and the identification of the underlying mechanisms can be accomplished. Specifically, by analyzing the standard P1 patterning line ablated before the CIGS deposition, we reveal an anomalous emission-quenching effect that follows the edge of the molybdenum groove underneath. We further rationalize the origins of this effect by comparing the topography of the P1 edge through a scanning electron microscope (SEM) cross-section, where a reduction of the photoemission cannot be explained by a thickness variation. We also investigate the laser-induced damage on P1 patterning lines performed after the deposition of CIGS. We then document, for the first time, the existence of a short-range damaged area, which is independent of the application of an optical aperture on the laser path. Our findings pave the way for a better understanding of P1-induced power losses and introduce new insights into the improvement of current strategies for industry-relevant module interconnection schemes.     

NiCrAlFe精密电阻合金中的L12有序结构研究

有序结构的形成是决定NiCrAlFe精密电阻合金电学性能的关键因素。本文利用第一性原理赝势平面波方法，计算了合金处于无序固溶体结构和形成L12型有序结构时的结合能、态密度、晶格常数等参数，并利用高分辨透射电子显微镜（HRTEM）对合金进行了结构表征，还测试了固溶态和时效态的电阻率。从结合能来看，该合金形成L12有序结构时比无序固溶体更加稳定；态密度以及部分态密度计算结果则表明，在L12有序结构中，Ni、Cr、Al、Fe会强烈成键而使得整个合金体系变得稳定；HRTEM分析结果证明固溶态合金经过和时效处理后出现了L12有序结构，而且该有序结构的晶格常数与计算值基本一致。对比无序固溶体与L12型有序结构费米能级处的态密度值发现，当形成L12有序结构时合金的导电能力较无序固溶体下降，电阻率升高，与实际测试结果吻合。     

高密度油基泥浆串联离心机固控系统设计分析

针对低速离心机无法回收利用高密度油基泥浆中的重晶石粉,高速离心机处理量低且容易堵塞的问题,设计了低速-高速离心机串联固控系统。通过计算及分析,得到泥浆中固相颗粒在离心力作用下的运动规律。结合试验结果,分析了离心机转速对分离固相粒径的影响规律,确定了高、低速离心机的最佳转速。串联的低、高速离心机分别分离出钻井液中的10～50 μm颗粒,1～10 μm颗粒,既实现重晶石的回收利用、降低含油固相排放率,又提高了高速离心机去除小颗粒有害固相的效率。该系统已在南川某平台4号井应用,在泥浆密度1.5～1.6 g/cm³的条件下,节省重晶石用量150 t,含油固相排放率降低38.6%。     

Numerical study of strain development in high-density polyethylene geomembrane liner system in landfills using a new constitutive model for municipal solid waste

Tensile strain development in high-density polyethylene (HDPE) geomembrane (GMB) liner systems in landfills was numerically investigated. A new constitutive model for municipal solid waste (MSW) that incorporates both mechanical creep and biodegradation was employed in the analyses. The MSW constitutive model is a Cam-Clay type of plasticity model and was implemented in the finite difference computer program FLAC?. The influence of the friction angle of the liner system interfaces, the biodegradation of MSW, and the MSW filling rate on tensile strains were investigated. Several design alternatives to reduce the maximum tensile strain under both short- and long-term waste settlement were evaluated. Results of the analyses indicate that landfill geometry, interface friction angles, and short- and long-term waste settlement are key factors in the development of tensile strains. The results show that long-term waste settlement can induce additional tensile strains after waste placement is complete. Using a HDPE GMB with a friction angle on its upper interface that is lower than the friction angle on the underlying interface, increasing the number of benches, and reducing the slope inclination are shown to mitigate the maximum tensile strain caused by waste placement and waste settlement.     

Microstructure and electrical conductivity of La0.9Sr0.1 Ga0.8Mg0.2O2.85-Ce0.8Gd0.2O1.9 composite electrolytes for SOFCs

(100-x) wt.% La_0.9Sr_0.1 Ga_0.8Mg_0.2O_2.85 - x wt.% Ce_0.8Gd_0.2O_1.9 (x = 0, 5, 10, 20) electrolytes were prepared by solid-state reaction. The composition, microstructure, and electrical conductivity of the samples were investigated. At 300 ~ 600°C, the pure La_0.9Sr_0.1 Ga_0.8Mg_0.2O_2.85 electrolyte has a higher conductivity compared to the composite electrolytes, but at 650 ~ 800°C the 95 wt.% La_0.9Sr_0.1 Ga_0.8Mg_0.2O_2.85 - 5 wt.% Ce_0.8Gd_0.2O_1.9 composite electrolyte presents the highest conductivity, reaching 0.035 S cm⁻¹ at 800°C. The cell performances based on La_0.9Sr_0.1 Ga_0.8Mg_0.2O_2.85-Ce_0.8Gd_0.2O_1.9 electrolytes were measured using Sr₂CoMoO₆-La_0.9Sr_0.1 Ga_0.8Mg_0.2O_2.85 as anode and Sr₂Co_0.9Mn_0.1NbO₆ -La_0.9Sr_0.1 Ga_0.8Mg_0.2O_2.85 as cathode, respectively. At 800°C, the measured open-circuit voltages are higher than 1.08 V, and the maximum power density and current density of the fuel cell prepared with 95 wt.% La_0.9Sr_0.1 Ga_0.8Mg_0.2O_2.85 - 5 wt.% Ce_0.8Gd_0.2O_1.9 electrolyte reach 192 mW cm⁻² and 720 mA cm⁻², respectively.     

Semiconductor‐ionic materials could play an important role in advanced fuel‐to‐electricity conversion

Functional semiconductor‐ionic materials can be used to realize a single component or so‐called “three‐in‐one” fuel cell design. Such materials integrate the functionalities of fuel cell's anode, electrolyte, and cathode into one component. The underlying principle of a single‐component fuel cell design combines material band structures with ionic species/transport. The performance values of such devices could exceed that of traditional fuel cells. This could represent a major progress in fuel cell science and technology and lies grounds for a new direction of fuel cell R&D and commercialization.