Transient responses of double-curved sandwich two-layer shells resting on Kerr's foundations with laminated three-phase polymer/GNP/fiber surface and auxetic honeycomb core subjected to the blast load

This work uses refined first-order shear theory to analyze the free vibration and transient responses of double-curved sandwich two-layer shells made of auxetic honeycomb core and laminated three-phase polymer/GNP/fiber surface subjected to the blast load.Each of the two layers that make up the double-curved shell structure is made up of an auxetic honeycomb core and two laminated sheets of three-phase polymer/GNP/fiber.The exterior is supported by a Kerr elastic foundation with three characteristics.The key innovation of the proposed theory is that the transverse shear stresses are zero at two free surfaces of each layer.In contrast to previous first-order shear deformation theories,no shear correction factor is required.Navier's exact solution was used to treat the double-curved shell problem with a single title boundary,while the finite element technique and an eight-node quadrilateral were used to address the other boundary requirements.To ensure the accuracy of these results,a thorough comparison technique is employed in conjunction with credible statements.The problem model's edge cases allow for this kind of analysis.The study's findings may be used in the post-construction evaluation of military and civil works structures for their ability to sustain explosive loads.In addition,this is also an important basis for the calculation and design of shell structures made of smart materials when subjected to shock waves or explosive loads.

Effect of heat input and filler metals on weld strength of gas tungsten arc welding of AISI 316 weldments

The present work investigates the effect of filler metals and heat input on weld bead geometry and mechanical properties of alloy316 welded by using GTAW.ER309 L,ER316 L and ERNi Cr Mo-3 filler metals,are applied to study their effect on the weldment.Weld defects are examined using radiographic testing.The mechanical properties of welds are evaluated through uniaxial testing,hardness measuring,and bending test.The mechanical properties and cooling rate decrease with increasing heat input.Tensile strength,yield stress and percentage elongation of weldments using three fillers are determined.Best results are obtained using ERNi Cr Mo-3.Besides,weld nugget area,cooling time and solidification time increases with increasing heat input.Finally,applying bending test on weld samples,cracks,tearing and surface defects are not observed.

Grain refinement of bronze alloy by equal-channel angular pressing(ECAP) and its effect on corrosion behaviour

The corrosion behaviour of bronze alloy prepared by equal channel angular pressing(ECAP) was investigated in 3.5 wt. % Na Cl solution.Immersion corrosion tests and different electrochemical techniques were carried out. The results showed that ECAPed bronze samples exhibited higher corrosion resistance compared with the as-cast alloy and the passive current density decreased with increasing number of passes. Moreover,the morphology of alloys indicated that the corrosion damage on the surface of ECAPed bronze was smooth and uniform while the as-cast alloy suffered from selective corrosion.

Prediction of tensile strength of friction stir welded 6061 Al plates

The present paper investigates the prediction of tensile strength after friction stir welding(FSW)using artificial neural network(ANN)in the MATLAB program.The experimental results are used to develop the mathematical model.The combined influence of welding speed,rotation speed,and axial force on the tensile strength of 6061 Al plates is simulated.Results of the tensile test are used to train and test the ANN model.A multi-layer solution is developed using the ANN model to predict tensile strength.Back propagation(BP)method is initially trained using 80%of the experimental data,then,testing is performed with the rest of the data.Results indicate that predicted values are close to the corresponding measured values.

Effect of Alumina Particles Addition on Physico-Mechanical Properties of AL-Matrix Composites

Metal-matrix composites (MMCs) are attracting considerable interest worldwide because of their superior mechanical and tribological properties. This study describes multifactor-based experiments that were applied to research and investigates Aluminum matrix composite reinforced with 5, 10 & 15 wt% Alumina particles. Mechanical mixing technique was used for fabrication. Sintering was carried out in a vacuum furnace at 600°C for 1 hr. The effects of Alumina percentage on the density, microstructure, both electrical & thermal conductivities, hardness and compression strength was investigated. The results showed that sample containing 5 wt% Alumina is near-fully dense. Also it has the highest hardness and compression strength.

The Development of Using Elevators in Different Buildings

Elevators are one of the most important elements of vertical communication used in buildings.Especially in recent times,where high and high rise buildings have become a modern architectural phenomenon and the spread of architecture has become a feature of the age.Hence,the research discusses the technique of installing elevators in buildings.A general introduction to elevators and their types will be discussed,as well as a historical overview of the beginning of the idea of the elevator and the first buildings that were used.The technique of installing the elevator inside the building explained with the images shown components elevator.Also it will mention several speeds of modern elevators used in buildings,the world’s fastest elevator,ultra-rope technology and the reasons for choosing this technique in elevator components in high-rise buildings which may be used in the space elevator that will connect earth and space.As well it shows features of the wire used in the elevators of the Burj-Khalifa,the highest skyscraper in the world.Then it mentions a number of the most recent and newest elevators in the world,then research results and references.

Enhancing the Creep Resistance of Sn-9.0Zn-0.5Al Lead-Free Solder Alloy by Small Additions of Sb Element

The creep phenomenon is considered as one of the most important deformation mechanisms under working conditions. The present study has examined the microstructure and creep properties of Sn-9.0Zn-0.5Al solder alloy after adding a small amount of Antimony (Sb). Nominal compositions of Sb additions were chosen to be 0, 0.5, 1.0, and 1.5 wt.%. The minimum strain rate was reduced for the Sb containing solder alloy. The stress exponents, n, were found to be around 3.7 for all soldiers at 130°C. The stress exponent increases as the temperature drops from 100°C to 50°C, except for the 1.0% Sb alloy, where n 5.3 - 6.1 at all the temperature range (T = 50°C, 100°C and 130°C). The results reveal that the Sb-containing solder alloys have better creep resistance with greater ductility than the Sb-free alloy due to solid solution strengthening, and intermetallic compound SnSb particle hardening.

Influence of Reaction Conditions on Sol-Gel Process Producing SiO₂and SiO_2-P₂O₅Gel and Glass

The effect of H2O and the slow thermal annealing on the properties of pure silica (SiO2) and phosphosilicate (SiO2-P2O5) gel-glasses are presented. The monolithic samples have been prepared via sol-gel process using tetraethorthosilicate (TEOS), Si(C2H5O)4 and Triethylphosphate (TEP) (C2H5O)3P(O) as SiO2 and P2O5 precursors. Phosphate incorporates into the silicate network by substituting Si atoms and consequently, we observed changes in structural and spectroscopic properties for these systems. The structures of prepared samples were examined by observed weight loss, XRD and FTIR. It has been found that in the structure of pure silica and phosphosilicate glasses there are formed domains characterized by certain degree of ordering of the units present in their composition, while the structure of pure silica is still amorphous of these glasses. The changing character of domains structure may be the reason of different chemical activities of phosphosilicate glass.

Fabrication, Microstructure, Thermal and Electrical Properties of Copper Heat Sink Composites

Copper as well as copper base composites reinforced with coated and uncoated 1 wt% diamond, graphite particles or short carbon fibers are prepared by powder metallurgy process. The reinforcement particles were encapsulated with silver as well as copper layer by using the electroless deposition technique to investigate the influence of the reinforcement surface coating on the microstructure, density, electrical and thermal properties of the sintered samples. The coated and the uncoated powders were cold compacted at 600 MPa, and then sintered at 1173 K (900°C) for 2 h under hydrogen atmosphere. The phase composition, morphology and microstructure of the prepared powders as well as the copper base sintered composites were investigated using X-ray diffraction analysis (XRD) and Scanning Electron Microscope (SEM) equipped with an Energy Dispersive Spectrometer (EDS) respectively. The density of the sintered composites was measured by Archimedes method. The copper base consolidated composites had a density up to 96% and the reinforcement coated particles were distributed uniformly within the copper matrix better than the uncoated one. The electrical resistivity at room temperature and the heat transfer conduction of the produced samples were measured in a temperature range between 323 K (50°C) and 393 K (120°C). The results observed that the sintered materials prepared from the coated powder have lower electrical resistivity than the sintered materials prepared from the mixed powders. On the other hand the thermal conductivity values were calculated using the heat transfer conduction values by means of the Fourier formula. The results observed that the thermal conductivity of copper is (391 W/m·K), 1 wt% diamond/Cu is (408 W/m·K), 1 wt% graphite coated silver/Cu is (393 W/m·K), 1 wt% Cu coated short carbon fiber/Cu is (393 W/m·K), graphite/Cu is (383 W/m·K) and short carbon fiber/Cu is (382 W/m·K). The obtained composites are expected to be suitable for heat sink applications. The heat transfer testing experiments were done. The forced convection of the present work was done and compared with the previous work in the literature, and satisfactory agreement was achieved.

钛沉积工艺制备TiN/cBN和TiC/金钢石涂层颗粒(英文)

用钛熔盐沉积及热处理工艺分别制备碳化钛涂覆的立方碳化硼颗粒(TiN/cBN)及碳化钛涂覆的金刚石颗粒(TiC/金刚石)。将cBN或金刚石颗粒分别与钛粉和KCl、NaCl和K2TiF6熔盐混合。将所得混合物在Ar气氛中加热至900°C,然后在H2气氛中于1000°C进行热处理。采用扫描电镜、X射线衍射和聚焦离子束技术对所制得颗粒进行表征。结果表明:cBN和金刚石颗粒表面已覆盖了纳米钛层。对Ti/cBN和TiC/金刚石涂层颗粒进行热处理后,颗粒表面沉积的Ti层与cBN和金刚石颗粒发生了原位化学反应,分别转化为钛化合物TiN和TiC。

铁对粉末冶金法制备铝基复合材料微观组织和力学性能及磁学性能的影响(英文)

研究铁对粉末冶金法制备铝基复合材料微观组织、力学性能及磁学性能的影响。利用机械混合制备含0,5%,10%和15%Fe(质量分数)的铝基复合材料。Al-Fe混合粉末经压制后在真空炉中600°C烧结1 h。XRD结果表明:在含有5%和10%Fe的试样中只有Fe和Al的衍射峰,而含有15%Fe的试样中则存在Al和Al13Fe4的衍射峰。实验结果表明:随着Fe含量的增加,材料的致密度和导热性变差。复合材料中的Fe可以提高其强度和硬度。材料的强化机制包括基体的晶粒细化,Fe颗粒的均匀分布以及Al13Fe4金属间化合物的形成。含有5%Fe试样的磁化强度为0.3816×10-3A·m2/g,对于含有10%Fe的试样,其磁化强度增加至0.6597×10-3A·m2/g,而对于含有15%Fe试样,其磁化强度降低至0.0702×10-3A·m2/g。这是由于在高铁试样中形成了反磁性的Al13Fe4金属间化合物导致磁化强度降低。

An Active-Only Temperature-Insensitive Current-Mode Biquad Filter Based on Differentiator Structures Employing CCCCTAs

This article presents an active-only current-mode universal biquad filter performing three standard functions: low-pass, high-pass and band-pass function, which can be readily modified to achieve the rest functions (band-stop and all-pass). The circuit principle is based on active-only circuit designed by using differentiators which are constructed from current controlled current conveyor transconductance amplifier (CCCCTA) cooperating with an internally frequency compensated operational amplifier (OA). The features of the circuit are that: the pole frequency and quality factor can be independently tuned via the input bias currents and it is ideally temperature-insensitive, its circuit description is very simple, consisting of 3 CCCCTAs and 2 operational amplifiers, and the proposed circuit is very appropriate for further developing into integrated circuit architecture. The PSpice simulation results are shown. The given results agree well with the theoretical anticipation.

Waste heat water pumping model with direct contact cooling

The performance of a patented water pumping model with steam-air power was presented, which operates automatically by direct contact cooling method. The main objective was to study feasibility of a pumping model for underground water. In this model, a heater installed within the heat tank represented sources of waste heat as energy input for finding appropriate conditions of the 10 L pump model. The system operation had five stages: heating, pumping, vapor flow, cooling, and water suction. The overall water heads of 3, 4.5, 6 and 7.5 m were tested. At the same time, it was found that the pump with 50% air volume is sufficient for pumping water to a desired level. In the experiment, the temperatures in the heating and pumping stages were 100-103 °C and 80-90 °C, respectively. The pressure in the pumping stage was 12-18 kPa, and the pressure in the suction stage was about-80 kPa, sufficient for the best performance. It could pump 170 L of water at a 2 m suction head, 120 L at a 3.5 m suction head, 100 L at a 5 m suction head, and 65 L at a 6.5 m suction head in 2 h. A mathematical model for larger pumps was also presented, which operates nearly the same as the present system. Economic analysis of the 10 L pump was also included.

The fractional coupled KdV equations: Exact solutions and white noise functional approach

Variable coefficients and Wick-type stochastic fractional coupled KdV equations are investigated. By using the mod- ified fractional sub-equation method, Hermite transform, and white noise theory the exact travelling wave solutions and white noise functional solutions are obtained, including the generalized exponential, hyperbolic, and trigonometric types.

Opto-Video Encryption Based on Logistic Adjusted Sine map in FrFT

In the last few years,videos became the most common form of information transmitted over the internet,and a lot of the traffic is confidential and must be protected and delivered safely to its intended users.This introduces the challenges of presenting encryption systems that can encode videos securely and efficiently at the same time.This paper presents an efficient opto-video encryption system using Logistic Adjusted Sine map(LASM)in the Fractional Fourier Transform(FrFT).In the presented opto-video LASM-based FrFT scheme,the encoded video is split into distinct frames and transformed into optical signals utilizing an optical supply.Each of the developed optical video frames is ciphered by utilizing the LASM in optical FrFT system using two-phase modulation forms on the video frame,the first in the time-domain and the second in the FrFT domain.In the end,the ciphervideo frame is spotted utilizing a CCD digital camera and transformed into a digital structure that can be managed using a computer.We test the proposed opto-video LASM-based FrFT scheme using various security tools.The outcomes demonstrate that the presented scheme can effectively encrypt and decrypt video signals.In addition,it encrypts videos with a high level of encryption qualitywithout sacrificing its resistance to noise immunity.Finally,the test outcomes demonstrate that the presented scheme is immune to known attacks.

Efficient Approach for Monitoring and Controlling Water Parameters Utilizing Integrated Treatment Based on WSNs

Research works of Wireless Sensor Networks (WSNs) applications and its constraints solutions occupy wide area around the world and attract many researchers. In this paper, an important one of environmental WSN applications is presented that is the water monitoring applications. An efficient approach for monitoring and controlling water parameters in real-time is implemented utilizing merging between WSN and designed simple workstation. For implementation simplicity, two water parameters (pH and temperature) are monitored and controlled in the proposed approach. Most of past work of water monitoring presented different proposed monitoring scenarios for different water parameters only. This research work utilizes the concept of interactive WSN nodes. The interactive nodes interact with the monitored water parameters to control its value. In the base station, the collected data is analyzed and the real-time value of the monitored parameters appears on the designed Graphic User Interface (GUI). The GUI is designed using the Matlab program. Through the GUI, the operator can switch the control between automatic and manual. ZigBee module is used for implementing the wireless communications between the nodes and the workstation. Due to the cost and simplicity, two sensors only are used in the proposed approach. Different real-time experiments are performed to test and measure the effectiveness and performance of the presented approach. These experiments reveal that the presented approach is effective for water treatment and efficient more than the past proposed water monitoring scenarios.

Analytical Approach to Exact Solutions for the Wick-Type Stochastic Space-Time Fractional KdV Equation

This study is devoted to giving an analytical approach to exact solutions for the Wick-type stochastic spacetime fractional KdV equation. By means of Hermite transform, white noise theory, and the fractional Riccati equation method, we derive white noise functional solutions for the Wick-type stochastic space-time fractional KdV equations. Exact traveling wave solutions for the variable coefficients space-time fractional KdV equations are given by using the fractional Riccati equation method. The obtained results include soliton-like, periodic, and rational solutions.