Oxidation Kinetics of Aluminum Powders in a Gas Fluidized Bed Reactor in the Potential Application of Surge Arresting Materials

In this technical paper, the oxidation mechanism and kinetics of aluminum powders are discussed in great details. The potential applications of spherical aluminum powders after oxidation to be part of the surging arresting materials are discussed. Theoretical calculations of oxidation of spherical aluminum powders in a typical gas fluidization bed are demonstrated. Computer software written by the author is used to carry out the basic calculations of important parameters of a gas fluidization bed at different temperatures. A mathematical model of the dynamic system in a gas fluidization bed is developed and the analytical solution is obtained. The mathematical model can be used to estimate aluminum oxide thickness at a defined temperature. The mathematical model created in this study is evaluated and confirmed consistently with the experimental results on a gas fluidization bed. Detail technical discussion of the oxidation mechanism of aluminum is carried out. The mathematical deviations of the mathematical modeling have demonstrated in great details. This mathematical model developed in this study and validated with experimental results can bring a great value for the quantitative analysis of a gas fluidization bed in general from a theoretical point of view. It can be applied for the oxidation not only for aluminum spherical powders, but also for other spherical metal powders. The mathematical model developed can further enhance the applications of gas fluidization technology. In addition to the development of mathematical modeling of a gas fluidization bed reactor, the formation of oxide film through diffusion on both planar and spherical aluminum surfaces is analyzed through a thorough mathematical deviation using diffusion theory and Laplace transformation. The dominant defects and their impact to oxidation of aluminum are also discussed in detail. The well-controlled oxidation film on spherical metal powders such as aluminum and other metal spherical powders can potentially become an important part of switch devices of surge arresting materials, in general.

A Review: On Smart Materials Based on Some Polysaccharides;within the Contextual Bigger Data, Insiders, “Improvisation” and Said Artificial Intelligence Trends

Smart Materials are along with Innovation attributes and Artificial Intelligence among the most used “buzz” words in all media. Central to their practical occurrence, many talents are to be gathered within new contextual data influxes. Has this, in the last 20 years, changed some of the essential fundamental dimensions and the required skills of the actors such as providers, users, insiders, etc.? This is a preliminary focus and prelude of this review. As an example, polysaccharide materials are the most abundant macromolecules present as an integral part of the natural system of our planet. They are renewable, biodegradable, carbon neutral with low environmental, health and safety risks and serve as structural materials in the cell walls of plants. Most of them are used, for many years, as engineering materials in many important industrial processes, such as pulp and papermaking and manufacture of synthetic textile fibres. They are also used in other domains such as conversion into biofuels and, more recently, in the design of processes using polysaccharide nanoparticles. The main properties of polysaccharides (e.g. low density, thermal stability, chemical resistance, high mechanical strength…), together with their biocompatibility, biodegradability, functionality, durability and uniformity, allow their use for manufacturing smart materials such as blends and composites, electroactive polymers and hydrogels which can be obtained 1) through direct utilization and/or 2) after chemical or physical modifications of the polysaccharides. This paper reviews recent works developed on polysaccharides, mainly on cellulose, hemicelluloses, chitin, chitosans, alginates, and their by-products (blends and composites), with the objectives of manufacturing smart materials. It is worth noting that, today, the fundamental understanding of the molecular level interactions that confer smartness to polysaccharides remains poor and one can predict that new experimental and theoretical tools will emerge to develop the necessary understanding of the structure-property-function relationships that will enable polysaccharide-smartness to be better understood and controlled, giving rise to the development of new and innovative applications such as nanotechnology, foods, cosmetics and medicine (e.g. controlled drug release and regenerative medicine) and so, opening up major commercial markets in the context of green chemistry.

Technical Note and Brief Overview of the Materials Science and Technology along with Designing Aspects for Development of Spintronic Devices with Optimum Efficiency

One of the major challenges in designing and fabricating Spintronic devices is the choice of both, Materials and the Technology, along with understanding the intricacies of the Designing aspects. In this communication, we have attempted to briefly discuss these factors, with an aim to draw the attention of the Materials Scientists and Technologists to this serious challenge, in the direction of which, though a lot of research and development work has been done, still needs more concerted efforts to be made in order to make the Spintronic devices that can offer good efficiency for maximizing their usefulness.

Augmenting the Heat Sink for Better Heat Dissipation

Heat sinks were invented to absorb heat from an electronic circuit conduct, and then to dissipate or radiate this heat to the surrounding supposedly, ventilated space, at a rate equal to or faster than that of its buildup. Ventilation was not initially recognized as an essential factor to thermal dispersion. However, as electronic circuit-boards continued to heat up, circuit failure became a problem, forcing the inclusion of miniaturized high speed fans. Later, heat sinks with fins and quiet fans were incorporated in most manufactured circuits. Now heat sinks come in the form of a fan with fans made to function as fins to disperse heat. Heat sinks absorb and radiate excess heat from circuit-boards in order to prolong the circuit’s life span. The higher the thermal conductivity of the material used the more efficient and effective the heat sink is. This paper is an attempt to theoretically design a heat sink with a temperature gradient lower than that of the circuit board’s excess heat.

Neural network-based model for prediction of permanent deformation of unbound granular materials

Several available mechanistic-empirical pavement design methods fail to include predictive model for permanent deformation(PD)of unbound granular materials(UGMs),which make these methods more conservative.In addition,there are limited regression models capable of predicting the PD under multistress levels,and these models have regression limitations and generally fail to cover the complexity of UGM behaviour.Recent researches are focused on using new methods of computational intelligence systems to address the problems,such as artificial neural network(ANN).In this context,we aim to develop an artificial neural model to predict the PD of UGMs exposed to repeated loads.Extensive repeated load triaxial tests(RLTTs)were conducted on base and subbase materials locally available in Victoria,Australia to investigate the PD properties of the tested materials and to prepare the database of the neural networks.Specimens were prepared over different moisture contents and gradations to cover a wide testing matrix.The ANN model consists of one input layer with five neurons,one hidden layer with twelve neurons,and one output layer with one neuron.The five inputs were the number of load cycles,deviatoric stress,moisture content,coefficient of uniformity,and coefficient of curvature.The sensitivity analysis showed that the most important indicator that impacts PD is the number of load cycles with influence factor of 41%.It shows that the ANN method is rapid and efficient to predict the PD,which could be implemented in the Austroads pavement design method.

Non Destructive 3D, 4D Microscopy and Mineral Phase Characterization in Industrial Minerals, Composites to Construction Materials

Conventional electron and optical microscopy techniques require the sample to be sectioned, polished or etched to expose the internal surfaces for imaging. However, such sample preparation techniques have traditionally prevented the observation of the same sample over time, under realistic three-dimensional geometries and in an environment representative of real-world operating conditions. X-ray microscopy (XRM) is a rapidly emerging technique that enables non-destructive evaluation of buried structures within hard to soft materials in 3D, requiring little to no sample preparation. Furthermore in situ and 4D quantification of microstructural evolution under controlled environment as a function of time, temperature, chemistry or stress can be done repeatable on the same sample, using practical specimen sizes ranging from tens of microns to several cm diameter, with achievable imaging resolution from submicron to 50 nm. Many of these studies were reported using XRM in synchrotron beamlines. These include crack propagation on composite and construction materials; corrosion studies; microstructural changes during the setting of cement; flow studies within porous media to mention but a few.

Discussion on the Source of Ore-forming Materials of the Yinan Gold Deposit,Shandong

Based on the main characteristics of the tectonic -magmatic evolution of region and Tanlu fault zone,we have discussed ore-bearing magmatic rocks petrochemistry,strontium and lead isotope,and the source of ore-forming materials in Yinan skarn deposit in this paper.The petrochemical features show that the ore-bearing magmatic rocks are calc-alkaline rocks of sub-alkaline series formed during

In situ atomic-scale observation of size-dependent (de) potassiation and reversible phase transformation in tetragonal FeSe anodes

Potassium-ion batteries(PIBs)are considered promising alternatives to lithium-ion batteries owing to cost-effective potassium resources and a suitable redox potential of-2.93 V(vs.-3.04 V for Li+/Li).However,the exploration of appro-priate electrode materials with the correct size for reversibly accommodating large K+ions presents a significant challenge.In addition,the reaction mecha-nisms and origins of enhanced performance remain elusive.Here,tetragonal FeSe nanoflakes of different sizes are designed to serve as an anode for PIBs,and their live and atomic-scale potassiation/depotassiation mechanisms are revealed for the first time through in situ high-resolution transmission electron micros-copy.We found that FeSe undergoes two distinct structural evolutions,sequen-tially characterized by intercalation and conversion reactions,and the initial intercalation behavior is size-dependent.Apparent expansion induced by the intercalation of K+ions is observed in small-sized FeSe nanoflakes,whereas unexpected cracks are formed along the direction of ionic diffusion in large-sized nanoflakes.The significant stress generation and crack extension originating from the combined effect of mechanical and electrochemical interactions are elucidated by geometric phase analysis and finite-element analysis.Despite the different intercalation behaviors,the formed products of Fe and K_(2)Se after full potassiation can be converted back into the original FeSe phase upon depotassiation.In particular,small-sized nanoflakes exhibit better cycling perfor-mance with well-maintained structural integrity.This article presents the first successful demonstration of atomic-scale visualization that can reveal size-dependent potassiation dynamics.Moreover,it provides valuable guidelines for optimizing the dimensions of electrode materials for advanced PIBs.

Exploration of Ideological and Political Materials for the Course of Inorganic and Analytical Chemistry for Environmental and Ecological Engineering Major

Integrating ideological and political theories teaching into the whole process of classroom teaching construction is a new requirement for implementing the fundamental task of cultivating people by virtue and playing the role of collaborative education.In order to realize the seamless integration of inorganic and analytical chemistry courses and ideological and political education,this paper summarizes the current situation of ideological and political research on inorganic and analytical chemistry courses in three major databases in China(VIP,CNKI and Wanfang),and sorts out the knowledge points,ideological and political elements and educational goals according to the content of the course chapters,to provide a basic guarantee for the ideological and political education construction of the course.

有限宽板孔边弹塑性变形测试

测量应变集中区域的弹塑性变形,对于研究材料损伤或微裂纹的产生,以预防宏观裂纹的产生及扩展具有重要的意义。为给航空发动机轮盘的损伤容限设计研究提供相关材料的力学实验参数,做了两个有限宽中心带孔试件的拉伸试验。试验中,采用单调逐级加、卸载的循环加载方式,并应用自动网格法和数字图像相关技术测量了孔周的全场位移分布。再应用最小二乘法将离散的位移分量拟合成二元多项式函数,求解出拉伸方向的应变分布,并给出孔边应力σ与孔边应变εy的关系曲线。

秦岭山地民居墙体构造技术

中国传统民居建筑起源和发展于经济技术落后的农业和手工业社会,历经千百年来自然与社会变革的影响,逐步演变进化成为地域特征强烈的乡土居住建筑体系。从与资源和环境的关系来审示,传统民居具备结构简洁、就地取材和施工建造方便等优点;从与气候的关系来看,具有适应地区气候、冬暖夏凉的生态性能;从以人对居住的需求来看,能够满足基本的舒适和健康标准要求。目前我国每年乡镇新建住宅已逾10亿m2,应该将传统民居中的生态建筑经验在新建住宅中得以继承。本文针对传统民居的代表之一———秦岭山地夯土墙民居建筑墙体材料、裂缝、防水、稳定性等问题,通过实验室试验和理论分析,得出其构造技术体系上的一些量化结论和定性做法。这对有地域代表的民居给予了技术上的肯定,对于民居的建造具有指导意义(已用于当地民居建造),同时将为我国乡土民居相关设计标准的建立提供科学依据。

La_(1-x)Ca_xFeO_(3-δ)系阴极材料的GNP法合成及电性能研究

采用甘氨酸鄄硝酸盐(GNP)法合成了LaFeO3及La1-xCaxFeO3-δ(x=0.1￣0.5)系列粉体,用TG鄄DTA、XRD、TEM、SEM等对产物形成过程及微结构进行了表征。结果表明,所合成的系列样品均形成钙钛矿结构的单相固溶体。在x≤20mol%的Ca含量范围内,产物为正交钙钛矿结构;当x>30mol%时,转变为立方钙钛矿相。相同条件下产物的衍射峰强度、晶胞体积及晶粒尺寸都随Ca含量的增大而减小。采用直流四端子法测量了烧结体在中温(450￣800℃)区的电导率。掺杂使样品导电能力显著增强,电导率随Ca2+掺入量的增大先增大后减小,La0.6Ca0.4FeO3-δ样品的电导率最高。在低温段,各样品的导电行为符合小极化子导电机制,导电活化能为13.67￣22.70kJ·mol-1。

Body armour-New materials, new systems

This is a very timely review of body armour materials and systems since new test standards are currently being written, or reviewed, and new, innovative products released. Of greatest importance, however, is the recent evolution, and maturity, of the Ultra High Molecular Weight Polyethylene fibres enabling a completely new style of system to evolve e a stackable system of Hard Armour Plates. The science of body armour materials is quickly reviewed with emphasis upon current understanding of relevant energy-absorbing mechanisms in fibres, fabrics, polymeric laminates and ceramics. The trend in ongoing developments in ballistic fibres is then reviewed, analysed and future projections offered. Weaknesses in some of the ceramic grades are highlighted as is the value of using cladding materials to improve the robustness, and multi-strike performance, of Hard Armour Plates. Finally, with the drive for lighter, and therefore smaller, soft armour systems for military personnel the challenges for armour designers are reported, and the importance of the relative size of the Hard Armour Plate to the Soft Armour Insert is strongly emphasised.

A Multi-Criteria Decision Support System for the Selection of Low-Cost Green Building Materials and Components

The necessity of having an effective computer-aided decision support system in the housing construction industry is rapidly growing alongside the demand for green buildings and green building products. Identifying and defining financially viable low-cost green building materials and components, just like selecting them, is a crucial exercise in subjectivity. With so many variables to consider, the task of evaluating such products can be complex and discouraging. Moreover, the existing mode for selecting and managing, often very large information associated with their impacts constrains decision-makers to perform a trade-off analysis that does not necessarily guarantee the most environmentally preferable material. This paper introduces the development of a multi-criteria decision support system (DSS) aimed at improving the understanding of the principles of best practices associated with the impacts of low-cost green building materials and components. The DSS presented in this paper is to provide designers with useful and explicit information that will aid informed decision-making in their choice of materials for low-cost green residential housing projects. The prototype MSDSS is developed using macro-in-excel, which is a fairly recent database management technique used for integrating data from multiple, often very large databases and other information sources. This model consists of a database to store different types of low-cost green materials with their corresponding attributes and performance characteristics. The DSS design is illustrated with particular emphasis on the development of the material selection data schema, and application of the Analytical Hierarchy Process (AHP) concept to a material selection problem. Details of the MSDSS model are also discussed including workflow of the data evaluation process. The prototype model has been developed with inputs elicited from domain experts and extensive literature review, and refined with feedback obtained from selected expert builder and developer companies. This paper further demonstrates the application of the prototype MSDSS for selecting the most appropriate low-cost green building material from among a list of several available options, and finally concludes the study with the associated potential benefits of the model to research and practice.

Effect of vertical stress rest period on deformation behaviour of unbound granular materials:Experimental and numerical investigations

Repeated load triaxial test is used to assess the deformation behaviour of unbound granular materials(UGMs) in flexible road pavements. Repeated load pulse characteristics(i.e. shape, loading period and rest period) are the stress configurations used in the experimental set-up to simulate the passing axle loads. Some researchers and standard testing protocols suggest a rest period of varying durations after a loading phase. A thorough review of existing literature and practises has revealed that there is no agreement about the effect of the rest period of vertical stress pulse on the deformation behaviour of the UGMs. Therefore,the main objective of this study is to investigate the effect of repeated stress rest period on the deformation behaviour of UGMs experimentally. Experiments are conducted, both with and without rest period, using basalt and granite crushed rocks from Victoria, Australia. Furthermore, in order to gain insight into the effect of the rest period, finite element modelling is also developed. Both the experimental and modelling results show that the rest period has a noticeable effect on both resilient and permanent deformation behaviours of UGMs. It is, therefore, recommended to take extra precautions while adopting a particular standard testing protocol and to supplement the results by additional tests with different loading configurations.

Simple Modifications to Standard TRIzol®Protocol Allow High-Yield RNA Extraction from Cells on Resorbable Materials

Resorbable bioceramics are attractive for medical applications such as bone substitution. Biochemical analysis on cells cultured on these biomaterials is vital to predict the impact of the materials in vivo and RNA extraction is an essential step in gene expression study using RT-qPCR. In this study, we describe simple modifications to the TRIzol? RNA extraction protocol widely used in biology and these allow high-yield extraction of RNA from cells on resorbable calcium phosphates. Without the modifications, RNA is trapped in the co-precipitated calcium compounds, rendering TRIzol? extraction method infeasible. Among the modifications, the use of extra TRIzol? to dilute the lysate before the RNA precipitation step is critical for extraction of RNA from porous ?-tricalcium phosphate (?-TCP) discs. We also investigate the rationale behind the undesirable precipitation so as to provide clues about the modifications required for other resorbable materials with high application potential in bone tissue engineering.

聚吡咯/SiO_2作导电助剂的水性环氧抗静电涂料的制备

以导电性聚吡咯/二氧化硅(PPy/SiO2)复合材料作导电助剂,与环氧树脂乳液混合,经聚酰胺X-650固化后,制备了电导率在10-9～10-4S·cm-1之间的水性环氧抗静电涂料。结果表明:PPy/SiO2用量为环氧乳液的2%(质量分数,下同)时,环氧涂层的电导率可从10-16S·cm-1提高到1.2×10-9S·cm-1,而且PPy/SiO2用量低于8%时,涂层具有良好的综合性能,对玻璃和马口铁附着力为1级,耐冲击性大于50cm,铅笔硬度H,耐水性和柔韧性优良。SEM观察结果表明:PPy/SiO2在环氧涂层中具有良好的分散性,且与环氧基体结合比较紧密。

Development of Specialized Courses and Establishment of Teaching Materials in Nursing of Integrated Chinese and Western Medicine

Since the Third Plenary Session of the 11 thCentral Committee of the Communist Party of China( CPC),with the promotion and development of traditional Chinese medicine(TCM),the pace of TCM nursing work has been accelerated in nationwide,and a group of integrated Chinese and western medicine nurses have been cultivated preliminarily. However,professional nurses of integrated Chinese and western medicine are still deficient extremely. The target of talent cultivation,based on the theory of "focusing on humanism,expanding diathesis,and enhancing practice to highlight the accommodation and integration of nurses of integrated traditional Chinese and western medicine",is to cultivate competent,practical and interdisciplinary senior nursing talents with strong professional basis,skilled operations,rich humanistic literacy,and sharp innovative spirit who not only master modern nursing knowledge and skills,but also can perform comprehensive nursing under the guidance of TCM theory of holistic concept and syndrome differentiation and nursing. This study,through investigating and analyzing the settings of3-year nursing professional courses in about 20 senior medical colleges,including senior nursing education of TCM,reformed the development of professional nursing courses of integrated Chinese and western medicine and the establishment of educational materials according to the course settings and educational work modes,so as to analyze the current status of nursing education of integrated Chinese and western medicine,determine course targets,and establish course system and educational work modes.

一种新的宏、细观变形全场测量方法(英文)

基于光学干涉和衍射理论,提出了一种新的用于宏、细观面内变形测量的光学方法。利用三束准直相干光之间的干涉,分别得到面内位移U+V和U-V的两幅耦合条纹图。借助于FFT相移技术,直接计算出全场的U和V分布。本实验系统中包含有长距离显微镜,三光束系统,数字图像采集和处理系统等。它具有光路简单,避开条纹级次的确定,直接计算得到U、V场等优点。将它用于热塑性复合材料 56层板AS4/PEEK[0/±45/90]7S三点弯曲梁位移场的宏、细观测量。得到了层间的变形规律。本文还利用三维各向异性弹性有限元法对AS4/PEEK[0/±45/90]7S三点弯曲梁进行了数值计算,得到了自由表面的位移场和应变场的数值解。定量分析了层间的变形传递规律,有助于进一步分析AS4/PEEK[0/±45/90]7S层合板宏、细观变形。

界面反射P-SV波转型超声散斑统计特性

对超声P波入射至强散射粗糙界面上时,反射声场中的转型SV波散斑的统计特性进行研究。根据Frensel-Huygens理论和自相关原理,得到了SV波散斑振幅概率密度函数的Rayleigh分布形式以及散斑平均横向尺寸的计算公式。进而又得到了,在使用具有一定尺寸孔径的横波探头时,所接收的SV波散斑的归一化声强的概率密度函数表达式,它与横波探头内接收到的平均散斑个数有关。在实验中,应用了两种不同孔径尺寸的横波探头对SV波的散斑声强进行测量。对测量所得的散斑合强度的数据进行统计分析的结果表明,实验值与理论值有较好的一致性。由此证实,上述理论分析的结果是正确的。