Effect of Silane Coupling Agent Concentration on Interfacial Properties of Basalt Fiber Reinforced Composites

The purpose of this study is to investigate the effect of the concentration of silane coupling solution on the tensile strength of basalt fiber and the interfacial properties of basalt fiber reinforced polymer composites.The surface treatment of basalt fibers was carried out using an aqueous alcohol solution method.Basalt fibers were subjected to surface treatment with 3-Methacryloxypropyl trimethoxy silane at 0.5 wt.%,1 wt.%,2 wt.%,4 wt.%and 10 wt.%.The basalt monofilament tensile tests were carried out to investigate the variation in strength with the concentration of the silane coupling agent.The microdroplet test was performed to examine the effect of the concentration of the silane coupling agent on interfacial strength of basalt reinforced polymer composites.The film was formed on the surface of the basalt fiber treated silane coupling agent solution.The tensile strength of basalt fiber increased because the damaged fiber surface was repaired by the firm of silane coupling agent.The firm was effective in not only the surface protection of basalt fiber but also the improvement on the interfacial strength of fiber-matrix interface.However,the surface treatment using the high concentration silane coupling agent solution has an adverse effect on the mechanical properties of the composite materials,because of causing the degradation of the interfacial strength of the composite materials.

Development of Glass Optical Fibers 1970-2020,Providing Us the Digitalized Communication World

New types of communication cables were found to be needed already during the 1960-decade,because the copper cables had,and still would have,too high attenuation and especially limited bandwidth,due to extremely high dispersion at communication signals above 2 Mbit/s.Already the first commercially available multimode optical fibers(1979),developed from pure silica glass with a Ge-doped core,had much lower attenuation at signal frequencies of the order of 2-9 Mbit/s and above it.However,fiber core,cladding and coating materials,cable structures and materials,as well as manufacturing-,measurements-and test methods have been needed to be developed much further to get the reliable fiber cable communication networks.The important development stages and solutions to the most significant childhood problems of the optical fibers and cables are described in this paper.Now over 500 million km of optical fibers are manufactured and installed worldwide for the communication networks.The understanding of how to make the fibers with the very good transmission,mechanical and reliability properties exists at the manufacturers of the fibers and cables.

Investigation and Benefits of the Use of Enzymes for Unbleached Kraft Recycling Wet Strength Paper at Lab and Industrial Scale

The deterioration of recycled fibers especially unbleached kraft with high wet strength resin content due to the irreversible structural changes caused by drying and added chemicals makes the raw material difficult to repulp.The mechanical effect in the pulper over time with chemical treatment has a negative impact on the recycled fibers.At lab scale,different compositions of enzymatic treatment C022L were under investigation to select the most efficient laccase Lacc1,Lacc2 or Lacc3 and to observe the impact of lipases during repulping at low and high consistencies.Pulp disintegration at different times was evaluated to define the level of rejects and to analyze the morphology of fibers after treatments.These results were more significant for Lacc2,by increasing the pulp consistency to 15%in the pulper.Combining lipases with CELODASE 022L appeared to decrease the efficiency of enzymes.The results showed a high reduction of energy power with the enzymatic treatment and a significant reduction of fines level in fibers’suspension.The most efficient version of C022L was used at industrial scale to compare directly with the standard conditions used in a paper mill.

Discussion on the Electron and Hole Effective Masses in Thermal Silicon

This review and research study provides conclusive discussion on the electron and hole effective masses in thermal silicon dioxide placing their values at 0.42m and 0.58m,where m is the free electron mass,correct to two decimal places.Only one of the masses needs to be determined as the electron and hole masses in materials add up to be equal to free electron mass with the hole effective mass being larger than the electron effective mass.The review also convinces the reader that the CBO(conduction band offset)or the Si-SiO2 barrier height at the oxide/silicon interface of a Si MOS(metal-oxide-semiconductor)device is 3.20 eV.

A Way to Determine the Maximum Inducible Residual Stresses in Steel by Mechanical Surface Treatment

The issue of determining the maximum compressive residual stress that can be induced through mechanical surface treatment is of great significance.There are two possible approaches,namely stress peening and stress rolling,both to determine the limit.Steel with high hardness may be under the yield strength,while for those with lower tensile strength,the hardness is increased,and the limit is above the tensile strength.

Effect of Dynamic Strain Aging on Hardness in the Heat-Affected Zone of SUS316 Steel Welds

DSA(dynamic strain aging)phenomenon in SUS316 steel was investigated using isothermal and non-isothermal tensile tests of simulated HAZ(heat-affected zone)thermal cycles.Isothermal tensile tests were performed on SUS316 in the peak temperature range of 20-700°C,with strain rates varying from 4.2×10^(-3)to 4.2×10^(-5)s^(-1).Based on the appearance of discontinuous plastic flows,expressed as serrations,and the hardening phenomenon of the tensile samples,the conditions for the occurrence of DSA in the SUS316 steel were investigated.Furthermore,the extent of hardening due to DSA was evaluated by comparing the hardness values of the SUS316 and SUS316EHP steels after the tensile tests.To confirm the effect of DSA on hardness in the HAZ of the welded SUS316 steel,non-isothermal tensile tests of the simulated HAZ thermal cycles were performed using a Thermec Master.The relationship between the increase in Vickers hardness due to DSA and the strain in the HAZ was determined;the effect of DSA on hardness in the HAZ could be predicted.The DSA in SUS316 steel was found to be mainly attributed to the dynamic interaction of dislocations with C and N interstitial atoms during high-temperature deformation.

Enhancing the Activity of N/C Catalyst for Oxygen Reduction Reaction by Fluorination

The synthesis of non-metal carbon catalysts with high catalytic activity for ORR(oxygen reduction reaction)in acidic media is a great challenge in the field of PEMFC(proton exchange membrane fuel cells).In this research,N-and F-codoped carbon catalyst with high performance was synthesized from ZIF-8 and NH4F,which are easily prepared structure and common chemical,respectively.The as-prepared catalyst has a high surface area of 789 m2/g and micro-porosity of~2 nm,facilitating more active sites to the ORR and O2 mass transfer in the diffusion of the catalyst matrix,respectively.The prepared N/C(NH4F)catalyst exhibited an onset potential of 0.94 V(vs.RHE)and a half-wave potential of 0.65 V in 0.1 M HClO4 solution.It also showed excellent durability in the cycling test of 10,000 times and a degradation shift of half-wave potential 70 mV was observed.Its diffusion-limiting current reached 5.85 mA/cm2 next to the theoretic value of 6 mA/cm2,suggesting that it has plenty of active sites for ORR,which could be attributed to fluorine introduction into the N/C catalyst.It proved that the introduction of fluorine into the structure of the N/C catalyst fine-tunes the Lewis basic sites of the carbon atoms adjacent to pyridinic and graphitic nitrogen species,facilitating the adsorption of oxygen molecules in the initial step of the ORR.The correlation between the N/C catalyst activity and the fluorination provides new insight into the ORR catalyst design.

Evaluation of Mechanical Properties of Highly Filled Jute Fiber Reinforced Composites

This study aims for development of highly filled jute fiber reinforced composites that contains jute fiber over fiber weight fraction 60%,and jute fiber reinforced composite was fabricated by the hot-pressing method.The molding temperature was changed from 175°C to 230°C,to investigate the effect of molding temperature on the mechanical properties of jute fiber reinforced composites.The effect of surface treatment of jute fiber on the mechanical properties of jute fiber reinforced composites was also investigated.As a result,the jute fiber reinforced composites using surface treated fiber has low porosity,and the jute fiber reinforced composite having low porosity has high flexural strength and modulus.The jute fiber reinforced composite using acetone treated fiber molded at 200°C has the maximum flexural strength and modulus.

Precious Metals Identification in Computer Motherboards

Elements can be classified into metals,nonmetals,or metalloids based on their chemical and physical properties.Precious metals are rare and expensive.There are ten known precious metals,three of which are of interest to investors,silver,gold,and platinum.The goal is to find physical methods to identify the presence of precious metals,silver,and gold in the metal components of the computer motherboard,and to confirm its presence by chemical methods for its use and its selling to the jewelry industry after it is physically separated from the computer motherboards.Physical and chemical tests were identified.Physical tests include inscription test,magnet test and specific gravity test for both silver and gold metal pieces and chemical tests include bleach test,nitric acid test,test karat solution kit,and jewelry test kits.

Properties of a MOS Device on Single Layer Molybdenum Disulfide

The properties of a metal-oxide-semiconductor device on a single layer MoS_(2)(molybdenum disulfide)semiconductor are determined theoretically utilizing the concept of physics that the carrier effective masses in materials are related to the intrinsic Fermi energy levels in materials by the universal mass-energy equivalence equation given as dE/E=dm/m,where E is the energy and m is the mass of the free electron.The known parameters of electron effective mass of 0.48 m and the direct bandgap of 1.8 eV for monolayer MoS_(2) semiconductor are utilized to determine the properties of the MOS(metal-oxide-semiconductor)device,with the given previous research consequence that the threshold for electron heating in SiO_(2) is 2 MV/cm-eV.

Creep Deformation of Mg-PSZ under Compressive Loading

Mg-PSZ(magnesia-partially-stabilized zirconia)has been studied under compressive loading at room temperature.Mechanical strain was recorded continuously using strain gauges while the sample phase composition and microstructure has been recorded at regular intervals on the ENGIN-X pulsed-neutron facility at the Rutherford-Appleton Laboratory in Didcot,England.Diffraction pattern analysis has been accomplished using the GSAS II software.The observed mechanical strain is time dependent,and a correlation is established between the mechanical creep strain and the phase and microstructural changes observed.Deformation and associated microstructural changes have been observed for all applied loads but were most marked for the highest load which was-1,200 MPa.It is suggested that the ongoing deformation and microstructural changes after unloading the specimen,are on account of a stress within the sample.

Three-Point Bending Test and Crack Detection by Acoustic Emission on Different Spring Steel Wires with Different Crystallographic Textures

In the production of compression springs,high forming velocities and grades of deformation during winding and setting may induce cracks that can lead to failure causing risks of an accident and damage.The AE(acoustic emission)technology,a non-destructive monitoring method,can detect acoustic signals reflected from cracks.To establish this method in the production of technical springs,it was necessary,to find out whether the AE signal is influenced by material properties,phase fractions distribution from tempered martensite,retained austenite,and microstructure including crystallographic texture.In addition,it was investigated to what extent the detected AE signal can be useful to separate between an actual crack and other material responses.Within an in-situ three-point bending test with the AE technology,macro-and micro-crack-typical AE signals were detected for five different spring steel wires(SH,VDSiCr,and FDSiCr according to EN-10270-1 and EN-10270-2).The relative energy related to the initiation,propagation,and growth of cracks caused by mechanical stress was measured using a piezoelectric sensor.If a crack AE signal appeared for the first time,the bending tests were stopped immediately.The results show that the frequency spectrum combined with the intensity of the acoustic signals generated during crack growth depends on the material properties and the crystallographic texture.Furthermore,it could be shown that it is possible to differentiate between micro-crack-typical AE signals and other signals that result from different material responses.

催化剂刻蚀方式对制备高质量碳纳米管的影响

对催化剂薄膜进行预处理是制备高质量定向碳纳米管必不可少的工艺环节。本文采用等离子体刻蚀和热刻蚀两种方法封Fe-Ni/Ti催化剂薄膜进行预处理，以确定哪种刻蚀方式封制备高质量定向碳纳米管更为有利。SEM观察和Raman光谱分析结果表明，热刻蚀比等离子体刻蚀更有利于制备出高质量的碳纳米管。

过程控制剂对机械合金化制备Cu-Cr纳米晶的影响

采用机械合金化工艺制备了Cu一5％Cr（质量分数）纳米晶粉末，运用激光粒度仪、X射线衍射（XRD）、扫描电镜（SEM）、透射电镜（TEM）和显微硬度计等实验手段研究了不同过程控制剂封机械合金化过程中粉末粒度，微观形貌，组织结构和显微硬度的影响。结果表明：当采用液体过程控制剂－无水乙醇和溶剂汽油时，所制备的粉末粒度与硬脂酸作为过程控制剂时相比较小，但由于液体过程控制剂增加了磨球运动时的阻力，从而导致了粉末晶粒细化效果减弱，同时晶格畸变减轻和显微硬度降低。在以硬脂酸为过程控制剂，球磨40小时，粉末晶粒达到11．2nm，晶格畸变为0．293％，微观硬度达到352HV。采用溶剂汽油为遏程控制剂时，由于存在较强的静电排斥力，有利于球磨过程中粉末的分散，封粉末粒度的细化效果优于无水乙醇。

不同pH下水合Al2O3纳米流体的稳定性和导热性实验研究

本文利用两步法制备了Al2O3水合纳米流体，测试了不同pH值下，不同体积分数的Al2O3纳米流体的zeta电位、粒径和导热系数，实验结果表明：对不同体积分数的Al2O3纳米流体，pH存在一个优化值对应zeta电位的最大绝对值和颗粒最小粒径；同样随着pH的变化，也存在一个最优值对应于Al2O3纳米流体的导热系数增加到最大值；在相同的pH下导热系数随纳米粒子体积分数增加而增大。因此实验结果表明，对Al2O3纳米颗粒来说，要得到稳定分散和高导热系数的纳米流体pH值应在8．5左右为最佳；纳米流体的稳定性和导热性与pH值有密切的关系，此结论与文献[5]和[13]中的结论一致。

表面修饰对磁性纳米复合微球的影响

用硅烷偶联剂封Fe3O4磁微粒子进行了表面修饰。并利用SEM、IR、古埃磁天平等手段封其结构与性能进行了表徵。分析了偶联剂用量对磁性纳米复合微球性能的影响。研究结果表明，经硅烷偶联剂修饰後的微球表面可带有多种有机功能基团，随着修饰剂用量的增大，微球表面包覆的功能基团也增多。当硅烷用量较少时，随着用量的增加，磁性能随之提高；而当硅烷用量达到一定值之後，继续增加用量，则会使磁性能降低。磁性纳米复合微球的分散性随着偶联剂用量的增加呈现先增加而后几乎不变的趋势。

新型含咪唑环的聚烷基芴电致发光材料的合成及性能研究

合成了一种新型的主链含咪唑环的聚烷基芴电致发光材料。目标聚合物热分解温度（Yd）为387°C，玻璃化温度（Tg）为169°C，具有良好的热稳定性。该聚合物主链含咪唑环，具有良好的电子传输性能，能有效提高器件的电致发光性能。用该聚合物为发光层作的结构为ITO／PEDOT（40nm）／PVK（40nm）／pO]ymer（80nm）／Ba（4nm）／A]（]60nm）的聚合物发光二极管（PLED）启亮电压为6．1v，最大亮度为224cdm^2。

自密实活性粉末混凝土的配制及其力学性能

利用聚羧酸盐减水剂配制了自密实活性粉末混凝土；采用砂浆坍落扩展度考察了减水剂掺量、水胶比、粉煤灰替代水泥比例、硅灰替代石英粉比例封活性粉末混凝土自密实性能的影响；同时也考察了这些因素对自密实活性粉末混凝土抗压、抗折强度的影响。研究表明，当聚羧酸盐减水剂用量为胶凝材料质量的2．5—3．0％，可配制出坍落扩展度在255mm以上，标准养护条件下28d抗压强度和抗折强度分别超过105MPa和16mPa的自密实活性粉末混凝土。

T5-15-3合金热变形固溶显微组织的多重分形研究

本文以T1-15-3（Ti-15V-3Cr-3Sn一3Al）合金热变形固溶再结晶显微组织的金相照片作为研究对象，基于Matlab．软件平台，自行开发了图像处理及多重分形分析程序，实现了从材料组织结构形貌图像土提取其相应的概率测度和标度指数的功能，并计算了多重分形谱。结果表明，在当前的观测尺度范围内，Ti一15—3合金热变形固溶再结晶显微组织具有多重分形特徵。且随着再结晶晶粒尺寸的增大和形变晶粒尺寸的减小，多重分形谱宽△α减小，表明显微组织分布越均匀。另外，在再结晶晶粒尺寸相差不大时，随着再结晶百分数的增大，最大最小概率子集维数的差值△f增加，再结晶晶粒为主导分布，显微组织更为细化均匀。这些研究为材料组织结构的定量表徵提供了新的思路。

朗道理论对铁氮相变的研究

应用朗道理论，通过引入序参量η，即单位体积中位矢（1／2，1／2，1／2）处晶格位置上被氮原子占有几率，将热力学势函数按η展开，讨论了η和温度T之间的关系。研究了αFe－γ｀Fe4N相变的位相关系并预测了相变过程申含有亚稳相出现。还应用点群理论推导了γ｀FenN相的形状。