Magnetic Field-Dependent Reversal Effect of the Electromagnet- Induced Normal Stress of Magnetorheological Materials

Magnetorheological (MR) materials are a type of magnetoactive smart materials, whose physical or mechanical properties can be altered by applying a magnetic field. In usual, MR materials can be prepared by mixing magnetic particles into non-magnetic matrices. In this work, the electromagnet-induced (or non-uniform magnetic field-induced) normal stress of MR materials is studied. It shows that the stress does not vary monotonically along with the enhancement of the applied magnetic field. There exists a field-dependent reversal effect of the variation of the stress. The reversal effect is thought resulting from that the ratio of interparticle repellent of parallel magnetic particles to the particle-electromagnet attraction gets enlarged along with the enhancement of the field.

Synthesis and Photocatalytic Activity of Polyhedral BiVO4

<p>Polyhedral BiVO₄ was prepared by hydrothermal-calcination two-step method. The physicochemical properties of polyhedral BiVO₄ were characterized by XRD, TG/DTA, SEM and UV-vis DRS. The photocatalytic properties of the samples were investigated by using 10 mg/L methylene blue (MB) as the target degradant. The experimental results showed that the prepared polyhedral BiVO₄ is monoclinic. The morphology is about 10 μm polyhedral block. The pure phase BiVO₄ has strong visible light absorption capacity. Under visible light irradiation, the prepared BiVO₄ can degrade 90% of MB within 40 min. Moreover, the photocatalytic performance was further improved by forming a BiVO4/BiOCl heterojunction, and the kinetic reaction rate was 1.5 times that of the pure phase BiVO₄</p>

The Progress of Composites with High Thermal Conductivity and Electromagnetic Shielding

<p>As electronic components develop toward high power, high package density, and device size miniaturization, heat dissipation and electromagnetic interference between electronic components are becoming more and more serious. In order to solve the adverse elec tromagnetic waves and heat radiation generated by electronic devices, people have high hopes for electronic packaging materials with high thermal conductivity and electromagnetic interference resistance. This paper summa rizes the research status of high thermal conductivity composite materials and electromagnetic shielding composite materials. Finally, the latest research results of high thermal conductivity and electromagnetic shielding composites are introduced, and the future development trend of new materials for microelectronic packaging is prospected.</p>

Finite Element Analysis and Experimental Study of Atomized Gas Flow Field in Spray Forming

<p align="justify">During the spray forming process of die steel, the gas flow field of nozzle atomizer has an important influence on the atomization effect of metal solution and the shape and performance of deposited billet. In this paper, the finite element analysis method was used to study the flow field distribution of the annular slot type restricted nozzle. The results showed that the negative pressure area was formed at the front of the atomizing gas outlet of the nozzle; the negative pressure area was enlarged and the negative pressure value was increased with the increase of the extending position of the liquid guide pipe and the atomizing pressure; when the atomizing pressure was 0.5MPa and the extending position of the liquid guide pipe was 7mm, the negative pressure value of the front of the liquid guide pipe could reach-38650Pa and the gas flow rate could reach 191.4m/s; the back-injection could be effectively avoided by optimizing the appropriate process parameters. And the damage of atomizing nozzle could be reduced.</p><p align="justify"> </p>

Research on Health Effects of Environmental Chemicals Based on Structure and Gene Association Analysis

<p>China is a major producer and consumer of chemicals. The production and use of chemicals play a role in the development of the entire national economy. Therefore, effective chemical management has a huge impact on the development of the national economy. At present, chemical management guidelines have achieved a lot in chemical operations, but there are still many shortcomings. Relevant institutions should further improve the standard system, strengthen the coordination of subjective institutions, the supervision and management, establish information standards, complete information sharing, build a feedback system, strengthen the transformation of experimental results and trust training.</p>

Combustion Derived SrTiO3: Synthesis, Characterization and Evaluation of Electrochemical Behavior Towards Quantification of Hg(II) Ions

<p>In this work, we are reporting the synthesis of porous SrTiO3 nanoparticles by using solution combustion route employing strontium nitrate and titanium-peroxo complex as oxidizer. The results of physico-analytical techniques revealed that SrTiO3 have a relatively small particle size, good dispersibility and diminished agglomeration. Powder X-ray diffraction pattern shows cubic perovskite structure (space group Pm3m) and the morphology was observed using a scanning electron microscope. The band gap of 3.24 eV was calculated using the diffuse reflectance spectrum. The surface area (~26.51 m2/g) of SrTiO3 was measured by BET method. SrTiO3 nanoparticles show violet-blue-green photoluminescence emission spectrum at room temperature. The photocatalytic degradation was carried out to investigate the photocatalytic activity of SrTiO3 under UV-light and evaluated for the electrochemical quantification of Hg(II) ions in aqueous solution using differential pulse anodic stripping voltammetry. The results reveal that SrTiO3 nanoparticles show better quantification result for Hg(II) ions. </p>

Desulfurization Of The Dibenzothiophene (DBT) By Using Imidazolium-Based Ionic Liquids(Ils)

In this work we examined the industrial scale extraction process of ultra-low sulfur diesel with the help of simulation software ASPEN Plus®. This work focuses on the [Cnmim] [BF4] (imidazolium-based) ionic liquid and employed it in the extractive desulfurization of the dibenzothiophene (DBT) from the model diesel fuel under a very mild process condition. UNIFAC (uniquasi functional activity) was chosen as the thermodynamic method to model the ionic liquid on ASPEN Plus® and different physical and chemical properties were then taken from the literature to be incorporated in the simulation model. Different parametric analysis was studied for the removal of thiophene-based compounds from the model diesel. The results acquired shows the significance of imidazolium-based ionic liquids (ILs) for the extraction of S-contents from the liquid fuels at an optimal process conditions of 40 ℃ and 2 bar pressure with the 2.8: 1 ratio of ionic liquid and model diesel which validates the experimental results obtained previously in the literature.

Role of Oxygen Pressure on the Surface Properties of Polycrystalline Cu2O Films Deposited By Thermal Evaporator

<p>Polycrystalline cuprous oxide (P-Cu2O) films are deposited on Cu substrates for various (0.2, 0.3 and 0.4 mbar) oxygen pressures (OP) by thermal evaporator. The XRD pattern shows the development of Cu (200), Cu2O (200) and Cu2O (311) diffraction planes which confirms the deposition of P-Cu2O films. The intensity of Cu2O (200) and Cu2O (311) planes is associated with the increase of OP. The crystallite size and microstrains developed in (200) and (311) planes are found to be 19.31, 21.18, 11.32 nm; 22.04, 23.11, 12.08 nm and 0.113, 0.103, 0.193; 0.099, 0.096, 0.181 with increasing OP respectively. The d-spacing and lattice constant are found to be 0.210, 0.128 nm and 0.421, 0.425 nm respectively. The bond length of P-Cu2O film is found to be 0.255 nm. The crystallites/unit area of these planes is found to be 12.21, 7.46, 45.16 nm-2 and 8.21, 5.75, 37.16 nm-2 respectively. The texture coefficients of these planes are found to be 1.22, 1.26, 1.11 and 0.78, 0.74 and 0.56 with increasing OP respectively. The O and Cu contents are found to be 5.31, 5.92, 6.94 wt % and 83.01, 82.44, 80.65 wt % respectively. The thickness and growth rate of P-Cu2O films are found to be 87.9, 71.9, 65.5 nm and 17.6, 14.2, 13.1 (nm/min) with increasing OP respectively. The SEM micro-structures reveal the formations of patches of irregular shapes, rounded nano-particles, clouds of nano-particles and their distribution depend on the increasing OP. The refractive index and energy band gap of P-Cu2O films are found to be 1.96, 1.89, 1.92 and 2.47, 2.44 and 2.25 eV with increasing OP respectively.<br /><br /></p>

Investigation of Metal Air-Cooling Process as An Element of Thermal Processing

<p>Background: Nowadays on metal tempering and annealing its air cooling (AC) is realized inside furnace with forced coolant delivery. Scientific tools lack for metal AC study and design is substantiated. The aim of this work is to investigate technological and design furnace parameters influence on metal AC duration, as well as disclosure of metal AC heat engineering regularities. Materials and method: For study mathematical model of metal AC is used. It bases on solving the differential non-stationary heat conductivity equation in one-dimensional form for cylindrical ingots and lining. Results: For three lining design types and different technological parameters operation acceleration possibility due to lining design change was studied. It is found that with ceramic fibers on walls and roof acceleration is 31-45% and with all lining made of ceramic fiber it is 44-52% as compared with fireclay brick lining. For a furnace with hearth of fireclay bricks and ceramic fiber on the walls and roof, convective component varies from 10 to 30%; for lining completely consisting of ceramic fibers it is 10 - 25%. When using fireclay brick lining parts their inner temperature is higher than for ceramic fiber up to 50 °C. Conclusions: Significant furnace lining materials type influence on metal AC intensity is proved. Heat removal mechanism on metal AC in furnace is disclosed, by establishing heat proportion directly removed from metal by convection. It is found that radiant heat transfer between metal and fireclay brick part of lining goes less intensively than with ceramic fiber part. </p>

Investigation of Mechanical Properties of Friction-welded AISI 304 with AISI 430 Dissimilar Steels

In this paper, standard SS304 austenitic stainless steel and SS430 ferritic steel cylindrical rods were fabricated by friction welding process by varying the frictional pressure and forge pressure in order to understand the effect of process parameter. The tensile strength and Vickers micro hardness tests were conducted for each fabricated joint to evaluate the mechanical properties of the welded specimen. It was found that sample S5 with friction pressure of 90 MPa and forging Pressure of 120 MPa has the high tensile strength value of 637 MPa and 372HV at the interface region. A detailed microstructural analysis was performed at the interface to reveal interconnecting of dissimilar metals.