Estimating the grain size of microgranular material using laser-induced breakdown spectroscopy combined with machine learning algorithms

Recent work has validated a new method for estimating the grain size of microgranular materials in the range of tens to hundreds of micrometers using laser-induced breakdown spectroscopy(LIBS).In this situation,a piecewise univariate model must be constructed to estimate grain size due to the complex dependence of the plasma formation environment on grain size.In the present work,we tentatively construct a unified calibration model suitable for LIBS-based estimation of those grain sizes.Specifically,two unified multivariate calibration models are constructed based on back-propagation neural network(BPNN)algorithms using feature selection strategies with and without considering prior information.By detailed analysis of the performances of the two multivariate models,it was found that a unified calibration model can be successfully constructed based on BPNN algorithms for estimating the grain size in the range of tens to hundreds of micrometers.It was also found that the model constructed with a priorguided feature selection strategy had better prediction performance.This study has practical significance in developing the technology for material analysis using LIBS,especially when the LIBS signal exhibits a complex dependence on the material parameter to be estimated.

Effect of Packing Materials and Other Parameters on the Air Stripping Process for the Removal of Ammonia from the Wastewater of Natural Gas Fertilizer Factory

Air-stripping method was used to remove ammonia from the wastewater collected from natural gas fertilizer factory. Different materials were used as packing materials for the air stripping system. The effect of pH over 10.5, air-water flow ratio, nature of packing materials, height of materials and initial influent concentration of ammonia on air stripping unit were investigated. An attempt has been made to find out the stripping con-stant. Stripping constant was found to be .001, 0014, .001 and .0009 for coal, plastic ring, stone chips and wood chips, respectively. Best result was found for plastic ring for its higher surface area. Wood chips did not give good result, because the chips amalgamate with each other and hence reduces the surface area.

Plasma-assisted ammonia synthesis in a packed-bed dielectric barrier discharge reactor:roles of dielectric constant and thermal conductivity of packing materials

In this article,plasma-assisted NH;synthesis directly from N;and H;over packing materials with different dielectric constants(BaTiO_(2),TiO_(2) and SiO_(2))and thermal conductivities(Be O,Al N and Al_(2)O_(2))at room temperature and atmospheric pressure is reported.The higher dielectric constant and thermal conductivity of packing material are found to be the key parameters in enhancing the NH;synthesis performance.The NH;concentration of 1344 ppm is achieved in the presence of BaTiO_(2),which is 106%higher than that of SiO_(2),at the specific input energy(SIE)of 5.4 k J·l^(-1).The presence of materials with higher dielectric constant,i.e.BaTiO_(2) and TiO_(2)in this work,would contribute to the increase of electron energy and energy injected to plasma,which is conductive to the generation of chemically active species by electron-impact reactions.Therefore,the employment of packing materials with higher dielectric constant has proved to be beneficial for NH;synthesis.Compared to that of Al_(2)O_(3),the presence of Be O and Al N yields 31.0%and 16.9%improvement in NH;concentration,respectively,at the SIE of5.4 k J·l^(-1).The results of IR imaging show that the addition of Be O decreases the surface temperature of the packed region by 20.5%to 70.3℃ and results in an extension of entropy increment compared to that of Al_(2)O_(3),at the SIE of 5.4 k J·l^(-1).The results indicate that the presence of materials with higher thermal conductivity is beneficial for NH;synthesis,which has been confirmed by the lower surface temperature and higher entropy increment of the packed region.In addition,when SIE is higher than the optimal value,further increasing SIE would lead to the decrease of energy efficiency,which would be related to the exacerbation in reverse reaction of NH;formation reactions.

Packing,compressibility,and crushability of rockfill materials with polydisperse particle size distributions and implications for dam engineering

In rockfill dam engineering,particle breakage of rockfill materials is one of the major factors resulting in dam settlement.In this study,one-dimensional compression tests on a series of coarse granular materials with artificially-graded particle size distributions(PSDs)were carried out.The tests focused on understanding the role of initial PSDs in the dense packing density,compressibility and crushability of coarse granular materials.The effects of fractal dimension(D)and size polydispersity(θ)of PSDs were quantitatively analyzed.Two different loading stages were identified from the logarithms of the stress-strain relationships,with the turning point marked as the yield stress.A similar effect of initial PSDs was observed on the packing density and low-pressure modulus of coarse granular materials.The packing density and low-pressure modulus increased monotonically withθ,and their peak values were attained at a D value of approximately 2.2.However,there was no unique correspondence between the dense packing density and low-pressure modulus.The particle breakage was influenced differently by the initial PSDs,and it decreased with the values of D andθ.The emergence of the unique ultimate state was also identified from both the compression curves and PSDs of the samples after the tests.The potential implications of the test results in the design of both low and high rockfill dams were also demonstrated.

Evaluation of Inocula and Packing Material for Acceleration of Start-Up in Biofilters

Several strategies with different combination of inocula and packing material were investigated to obtain the optimal start-up time and elimination capacity (EC) in toluene biofiltration. The inocula contained the activated sludge and toluene degrading bacteria, and the packing material consisted of different mixing ratios of peat and wood chips. A final toluene load of 21.2 g/(m3·h) was attained step by step in four parallel biofilters. A shortest start-up time of 15 days and a highest EC of 17.0 g/(m3·h) were observed in the biofilter B-4, which was inoculated with a special microbial consortium consisting of three strains of toluene degrading bacteria and was packed with the mixture of peat and wood chips at a ratio of 80:20 (w/w). These results indicated that inoculating pre-acclimatized microbes dramatically shortened the start-up time, and such a composition of packing material could maintain an appropriate environment (with the bed porosity and water content equating to 0.45 and 1.96, respectively) for the growth of dominant toluene degrading bacteria in the biofilter.

Application and Care of Two Kinds of Sphenoid Sinus Packing Materials after Pituitary Tumor Resection with the Transnasal Endoscopic Approach

Background: Neuroendoscopic transsphenoidal approach for resection of pituitary adenomas has the advantages of less damage, fewer complications, and a faster recovery than the traditional approach and has beening favored by neurosurgeons. However, there has no standard method of selecting suitable packing materials after the operation to relieve pain in patients and achieve the ideal hemostatic effect. We compared the postoperative complications and treatment effects of two different packing materials in patients with pituitary adenomas. Objective: To investigate the advantages and disadvantages of using a catheter balloon and iodoform gauze for hemostasis in patients undergoing pituitary tumor resection by neuroendoscopic transsphenoidal approach. Materials and Methods: We retrospectively analyzed these data of 48 cases treated with pituitary adenoma resection by the single nasal approach from January 2018 to October 2019 in Sun Yat-sen University Cancer Center. According to the type of sphenoid sinus packing material used, these patients were divided into balloon tamponade oppression group (24 cases) and tela iodoformum oppression group (24 cases), respectively. The balloon tamponade oppression group received catheter balloon tamponade oppression hemostasis, and the tela iodoformum oppression group underwent tela iodoformum oppression hemostasis. The outcomes and complications were compared between the two groups in which two kinds of sphenoid sinus packing materials were used for hemostasis after tumor resection by transnasal endoscopic approach. For the catheter balloon compression hemostasis method, on account of the plasticity of the balloon, the volume of water in the balloon can be adjusted according to the size of the patient’s own sphenoid cavity. The amount of bleeding and several complications in terms of discomfort during placement and removal of the packing material, rebleeding after removal of the packing, cerebrospinal fluid rhinorrhea and electrolyte disturbance are compared between the two groups. Results: 48 patients were enrolled. The two groups’ data of patients were similar in age structure, sex ratio, tumor size at baseline and so on. No complications, such as abscess formation, were found in both groups. The success rate in the compression with catheter balloon group was 100% (24 of 24 patients);and in the iodoform gauze group 83.33% (20 of 24 patients). A catheter balloon was more successful in stopping bleeding at early stage than iodoform gauze. There were no statistically significant differences in the hospitalization stay time, operating day to discharge day and tampon indwelling time (P > 0.05). There were also no significant differences in pairwise comparison between the catheter balloon group and iodoform gauze groups in the incidence of cerebrospinal fluid rhinorrhea or electrolyte disturbance between the two groups (P > 0.05). The incidence of headache in the catheter balloon group was statistically significantly lower than that in the iodoform gauze group (P < 0.05). Conclusion: In patients undergoing endoscopic pituitary tumor resection, compression and hemostasis by means of catheterization expansion lead to lower rates of injury and complications and have a good effect, so this method is worthy of being recommended for clinical practice.

SYNTHESIS OF INTERFERON-α_A MONOCLONAL ANTIBODY PACKING MATERIAL IN HIGH-PERFORMANCE AFFINITY CHROMATOGRAPHY AND PURIFICATION OF RECOMBINANT HUMAN INTERFERON-α_A

A new way for the synthesis of human interferon—α_A monoclonal antibody (IFN-α_A-McAb) bound to silica gel packing material in high-performance affinity chromatography (HPAFC) has been developed. The high coupling efficiency and specific activity of IFN—α_A-McAb can be obtained by activated diol-silica gel with activating agent. After purification using this packing material in HPAFC, the specific activity of recombinant human interferon-α_A (rIFN-α_A) rose up to 1.03×10~7IU/mg protein and the purification efficiency is appoximately 100 times.

The Effects of the Particle Size Ratio on the Behaviors of Binary Granular Materials

The particle size ratio(PSR)is an important parameter for binary granular materials,which may aect the microstructure and macro behaviors of granular materials.However,the eect of particle ratio on granular assemblies with dierent arrangements is still unclear.To explore and further clarify the eect of PSR in dierent packing structures,three types of numerical samples with regular,layered,and random packing are designed.Numerical results show that PSR has signi􀀀cant eects on binary granular samples with regular packing.The larger the PSR,the stronger the strength,the larger the modulus,and the smaller the angle between the shear band and the load direction.And a theoretical solution of the peak stress ratio vs.PSR is obtained for regular packing,and the results by DEM are in good agreement with the theoretical solution.Under layered packing,PSR has little eect on peak stress ratio due to similar microstructure obtained with the changing of PSR.The modulus slightly increased with the increase of PSR.Under random packing with small grain content of 50%,PSR has little eect in the range of 0.5–0.9,but in a larger range,larger PSR leads to greater modulus.

Understanding the influence of crystal packing density on electrochemical energy storage materials

Crystal structure determines electrochemical energy storage characteristics;this is the underlying logic of material design.To date,hundreds of electrode materials have been developed to pursue superior performance.However,it remains a great challenge to understand the fundamental structure–performance relationship and achieve quantitative crystal structure design for efficient energy storage.In this review,we introduce the concept of crystal packing factor(PF),which can quantify crystal packing density.We then present and classify the typical crystal structures of attractive cathode/anode materials.Comparative PF analyses of different materials,including polymorphs,isomorphs,and others,are performed to clarify the influence of crystal packing density on energy storage performance through electronic and ionic conductivities.Notably,the practical electronic/ionic conductivities of energy storage materials are based on their intrinsic characteristics related to the PF yet are also affected by extrinsic factors.The PF provides a novel avenue for understanding the electrochemical performance of pristine materials and may offer guidance on designing better materials.Additional approaches involve size regulation,doping,carbon additives,and other methods.We also propose extended PF concepts to understand charge storage and transport behavior at different scales.Finally,we provide our insights on the major challenges and prospective solutions in this highly exciting field.

Study on the Adsorption of Preservatives by Eyeliner Pen Packaging Materials

In order to study adsorption of preservatives by eyeliner pen package,the chemical compositions of the commercially available Eyeliner package were analyzed by infrared spectrometer.It was found that these package components were PP,PET,modified PP,modified PET,ABS,nylon,PU and so on.The adsorption effects of these components on three preservatives,i.e.phenoxyethanol,Methyl paraben and Propyl paraben have been further studied by high performance liquid chromatography.The results demonstrated that the four chemical materials PET,PP,modified PP and ABS had no adsorption on the above three preservatives.However,the component named of water diversion core which was composed of modified PET,and nylon-made cotton head have been observed of slight adsorption in this study.And components as the function of preventing liquid leakage,which was made of PU,have presented the most serious adsorption on these three preservatives,with the adsorption order as Propyl Paraben>Methyl Paraben>phenoxyethanol.

Nasal packing材料与传统鼻腔填塞材料治疗顽固性鼻出血的临床比较

目的：比较Nasalpacking（NP）鼻腔填塞材料与传统鼻腔填塞材料对顽固性鼻出血治疗的疗效。方法：制定顽固性鼻出血的诊断标准，并以此标准对312例鼻出血病人随机分为两组，分别用NP材料和传统鼻腔填塞进行止血处理。结果：NP材料在治愈率和好转率上与传统材料有统计学的差异（P＜0.05）。结论：NP材料与传统鼻腔填塞材料对顽固性鼻出血均有良好疗效。而NP材料具有操作简便、病人痛苦、并发症少等特点。可作为治疗顽固性鼻出血的首选填塞材料。

Properties and interfacial microstructure of cement-based materials with composite micro-grains

Silica fume, fly ash and nano-fiber mineral materials (NR powder) are employed to incorporate into cement-based materials. According to the grain grading mathematical model of cement-based materials, two packing systems, namely, spherical grading system and nano-fiber reinforced system were designed. Properties and interfacial microstructure of the two systems were studied according to secondary interface theory. It was shown that nano-fiber mineral materials can improve the grain grading of the admixture, increase the density of the system, improve the microstructure of the interface and the hardened paste, and enhance the uniformity of cement-based materials mixed with composite micro-grains and greatly increase their wearable rigidity and flexure strength. In this paper, two kinds of interface models, including spherical grain model and nano-fiber reinforced interface model of the cement-based materials mixed with composite micro-grains, were brought forward.

阴离子密堆二次电池正极材料中离子宿住迁移与能量存蓄机制晶体化学新探索

在二次电池电极材料中,有一类性能优良的材料具有阴离子密堆或近密堆方式构筑的晶体结构。宿住阳离子在密堆留下的空隙空间中宿住、迁移,从而实现能量转换与存储。相关过程微观机理的研究由于涉及原子尺度的微观结构辨析和电子层面的分析,实验研究难度较大。因此,更多是通过晶体学理论分析与晶体场理论和量子力学第一性原理计算结合展开。已有的理论从过渡金属配位体晶体场分析展开,但宿住离子宿住迁移中电子相互作用关注相对不足。本文根据已有的实验事实,在精准描述最具代表性的阴离子(氧离子)面心立方紧密堆积(FCC)结构中空隙空间准确形态和微分几何方法准确解析空腔真实体积的基础上,结合空隙空腔独特形态,对经典晶体学中Pauling第一规则的分析方法作了拓展。根据新的理解,提出了宿住阳离子在空隙空腔宿住和徒迁拓扑形变新模式,及其可能拥有的电子形态学新特征,提出了空隙空腔中宿住阳离子体积与密堆阴离子半径间的新关系。为了进一步说明住宿离子电子形态特征,通过第一性原理计算获得了典型FCC结构LiMn_(2)O_(4)尖晶石中电子密度等势图,构造了锂离子宿住四面体空隙空腔的电子密度等势特征分布的三维形态,与晶体学分析中获得的电子形态新特征变化一致。通过夹在两个密排面间的{110}面族电子云密度分布分析,首次清晰地揭示了LiMn_(2)O_(4)中锂离子的“S”形徒迁途径,及其对附近锰离子配位多面体电子云密度分布的影响。依据宿住离子脱/嵌新特征,提出阴离子拓扑多面体晶体场对宿住阳离子电子云压缩发生拓扑变形实现能量转换储蓄的新思路,据此计算了典型紧密堆积构造的电极材料新的理论能量密度,并和传统方法计算的理论值进行了比较,二者十分接近,为从晶体学和量子力学理解二次电池能量储存提供了新视角。

Estimation of Grain Size in Randomly Packed Granular Material Using Laser-Induced Breakdown Spectroscopy

Grain size is one of the most important physical parameters for randomly packed granular(RPG)materials.Its estimation,especially in situ,plays a key role in many natural and industrial processes.Here,the application of laser-induced breakdown spectroscopy(LIBS)was investigated experimentally to estimate the grain size in RPG materials.The experiment was performed by taking sieved copper microspheres with discrete median diameters ranging from 53 to 357μm as examples and by measuring the plasma emissions induced by 1064 nm laser pulses with a duration of 7 ns in an air environment(see Fig.1).

注水站高压注水泵盘根盒压帽断裂分析

中原油田高压注水泵盘根盒压帽出现多起断裂事故,给安全生产带来较大风险隐患。通过现场基本情况、压帽化学成分、硬度和金相组织的分析,再加上断口的宏观形貌、微观形貌分析等方法,查找压帽发生断裂原因。结果表明,压帽断裂原因一是由于铸造材质疏松,且存在缺陷;二是由于注水泵高压波动对断裂起到了关键性破坏作用,属于“材质因素和力学因素”共同作用导致的断裂。

复合材料包装箱模块化设计与成型技术研究

目的为了满足复合材料包装箱在交通运输方面的更多需求,本文研究出一种轻质、高强、耐腐蚀、防霉、安装轻便快捷的复合材料包装箱制造技术。方法本文通过包装箱设计与仿真分析、产品表征等工序开展研究,将包装箱设计成4种16块单元面板,通过材料筛选、模具设计、单元件成型工艺研究,完成面板制作,并进行单元件质量称量、力学性能表征试验。结果包装箱总质量较同规格金属箱子质量减少70%以上,力学测试结果显示实际弯曲强度较理论值高85.41%,泡沫加强筋平拉强度较理论值高出15.08%。结论研究结果表明模块化复合材料包装箱满足设计要求。

仿生葫芦储热单元潜热蓄热堆积床数值研究

在碳达峰与碳中和的“双碳”能源背景下,传统封装相变材料(PCM)的储热单元与潜热储热堆积床(LHTES)系统无法满足当前的储热需求,而仿生学在储热领域的应用,可以为二者储热效率的提升提供一种全新的思路。为此,提出一种仿生葫芦结构的新型储热单元以增加传热面积,提高LHTES系统的热性能。优化仿生葫芦单元结构的尺寸参数对单元熔融特性的影响,确定最优熔融特性的尺寸参数。分析传统球形和仿生葫芦LHTES的温度分布、液相率、蓄热能力等性能指标的影响。结果表明,葫芦结构可提升14.5%的单元换热面积,与传统模型相比,仿生模型液相率和储热完成率最大可分别提升12.67%和6.2%。在此基础上,分析入口温度和流速对系统性能的影响,结果表明,进口温度对系统的储热性能影响较大,进口温度增大15 K,堆积床系统的储热时间比原来缩短59.6%。该研究可为优化LHTES系统、提高实际条件下的热性能提供参考。

基于圆柱封装单元的水合盐相变储热填充床的储释特性实验研究

水合盐相变储热技术具有储热密度高、成本低等优势,在清洁供暖中具有广阔应用前景。本研究设计并搭建了以三水合乙酸钠作为储热材料,以圆柱形相变材料封装单元作为基础单元的填充床相变储热装置。通过实验研究填充床储热装置的运行特性,研究了流量和储热温度对装置的储释热用时、出口温度、热效率及储热密度的影响。实验结果表明:提高储热温度和增大流量可缩短储热用时、提升热效率和储热密度。储热装置的热效率可达94.73%,储能密度可达71.77 kW·h/m^(3)。

黄麻可降解包装材料制备及性能研究

研究一种基于黄麻、粘胶、水性聚氨酯和羧甲基纤维素钠(CMC)的可降解包装材料的制备。采用非织造生产工艺,以可降解的黄麻和粘胶为原料,纤维梳理成网后,经针刺机针刺,再将水性聚氨酯和CMC溶于水中,形成悬浮液均匀喷洒至纤维网,烘干后热压成型得到生物可降解包装材料。对比聚乳酸、水性聚氨酯、CMC的成本及力学性能,探究材料混比对黄麻/粘胶/水性聚氨酯/CMC包装材料断裂强力和断裂伸长率的影响,并通过干燥和湿润试样的强力对比,探究了黄麻/粘胶/水性聚氨酯/CMC包装材料的耐水性能。结果表明,当黄麻/粘胶/水性聚氨酯/CMC混比为40/40/15/5,面密度为100 g/m^(2)时,所得样品纵、横向断裂强力分别为155.5 N、52.6 N,将样品浸渍于水中1 h后取出,其纵、横向的湿态强力保留率分别为49.9%、69.2%,可满足包装袋力学性能的要求。

基于Cape Pack的军用物资单元包装优化研究

探讨了现代后勤对军用物资单元包装的要求,介绍了Cape Pack包装决策支持软件的主要功能,提出了基于该软件对军用物资单元包装优化的设计方案,最后通过案例演示了优化设计过程并对其结果进行分析,为军用物资单元包装优化提出了新的思路。