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In this work, two new mesomorphic bent-rod shape compounds containing bisoxadiazole rings are described. The relationship between the compound structure and the mesomorphic behavior as 3,3'-benzene-1,4-diylbis [5-(4-nitrophenyl)-1,2, 4-oxadiazole] and 3,3'-benzene-1,4-diylbis [5-(4-chlorophenyl)-1,2,4-oxadiazole] were established using different terminal groups (i.e., NO2, Cl). The mesomorphism was categorized using POM and DSC, while the compounds structure were characterized using FT-IR and ¹HNMR. [ABSTRACT FROM AUTHOR]

In this paper, we present research on the structural optimization of a rod in a 1-cylinder in-line thermal engine structure. To perform this optimization, we will use the finite element analysis program, ANSYS. We will parametrically model the connecting rod using ANSYS Design Modeler. Some geometrical dimensions, such as the radii of the connection, and the relief channels, we will consider as structural optimization parameters. The objective function of this optimization is to reduce stress concentrators, with the aim of increasing fatigue strength, but also to reduce connecting rod mass. We will present the results obtained, in the form of 3D graphs. We will present the optimal solution for the geometrical shape of the connecting rod. The study demonstrates the effectiveness of structural optimization programs to achieve optimal part design shapes effect. [ABSTRACT FROM AUTHOR]

This article represents research regarding use of pneumatic double acting cylinder with two in and out piston rods. A cylinder with two in and out piston rods in this paper is a pneumatic actuator. The cylinder with two in and out piston rods works only with compressed air. Besides, the compressed air usually has a pressure of between 2•105 Pa and 6•105 Pa. Cylinder with two in and out piston rods drive with solenoid can be used for various technical applications. In the paper all the circuits have cylinders with two in and out piston rods. These four circuits, simulate the operation of the cylinder with two in and out piston rods. We mention that the pneumatic and electro-pneumatic schemes given in this paper are made using FluidSim software from Festo. [ABSTRACT FROM AUTHOR]

Graphical abstract The effectiveness of filler metals in reducing the susceptibility of Al alloys 2024 and 6061 to solidification cracking was evaluated using the Transverse Motion Weldability (TMW) test, in which the lower sheet in lap welding is moved at the speed V in the transverse direction of welding to cause cracking in the weld. The speed V at which one weld edge moves away from the other during crack propagation is close to that in actual welding, thus suggesting the test results are realistic. For welding 2024 Al, filler metal 2319 Al was least effective and filler metals 4043 Al and 4145 Al were both very effective, especially 4145 Al. For welding 6061 Al, the new commercial filler metal 4349 Al designed to increase the weld strength was as effective as filler metal 4043 Al, which has been widely used for reducing solidification cracking in 6000-series Al alloys. Abstract The effectiveness of filler metals in reducing solidification cracking in welds of 2024 Al and 6061 Al was examined, these two Al alloys being highly susceptible to solidification cracking. The effectiveness was evaluated by the transverse motion weldability (TMW) test. 2024 Al was welded with filler metals 2319 Al, 4043 Al and 4145 Al. 4043 Al and 4145 Al both reduced cracking effectively, but 4145 Al was significantly better. 6061 Al was welded with filler metals 4043 Al and 4943 Al (a new alloy designed to increase the weld strength of the 6000-series alloys), and the effectiveness was similar. Micrographs and curves of temperature T vs. fraction solid f S of the weld metals were used to help explain the test results. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Twelve possible models of the researched interfaces were established. • Interfacial stability was influenced by termination structure and stacking sequence. • Interface energy of Ag-Cu-Ti/TiC interface is smaller than that of Ag-Cu-Ti/SiC one. • TiC layer plays the positive role on improving the reactive wettability. Abstract Interfacial properties of Ag (1 1 1)/SiC (1 1 1) interface and Ag (1 1 1)/TiC (1 1 1) interface were researched by first-principles calculations to investigate the reason that Ag-Cu-Ti filler metal shows the superior reactive wettability on SiC ceramic. The calculated results show that, 7 atom-layers Ag (1 1 1) surface, 11 atom-layer SiC (1 1 1) surface and 9 atom-layer TiC (1 1 1) surface can represent the Ag bulk, SiC bulk and TiC bulk, effectively. Ag (1 1 1)/SiC (1 1 1) interface and Ag (1 1 1)/TiC (1 1 1) interface with C-terminated structure and TL stacking sequence show the highest interfacial stability. Chemical bonds at Ag (1 1 1)/SiC (1 1 1) interface and Ag (1 1 1)/TiC (1 1 1) interface are mainly formed by the interaction between 1st layer C atoms in SiC (or TiC) slab and 1st layer Ag atoms in Ag slab. Interfacial energy of Ag (1 1 1)/SiC (1 1 1) interface is much larger than that of Ag (1 1 1)/TiC (1 1 1) interface, which indicates that the formed TiC reaction layer between Ag-Cu-Ti filler metal and SiC ceramic indeed plays the positive role on improving the wettability of Ag-Cu-Ti filler metal on SiC ceramic. [ABSTRACT FROM AUTHOR]

The material 36MnVS4 is the second generation of connecting rod fracture-split material. However, it generates more quality defects during the fracture-split process. To investigate the causes of defects that occurred, the material properties and fracture-split performance of the 36MnVS4 are researched and compared with C70S6. The fracture-split easily-induced defects are also analyzed. By finite element simulation and experimental analysis, the results show that the 36MnVS4 has lower carbon content and more ferrite, therefore the fracture surface of the 36MnVS4 connecting rod is more prone to tears and the plastic deformation range is greater. The fracture speed of the 36MnVS4 connecting rod is 20% lower than that of the C70S6 connecting rod. The slower fracture separation rate increases the possibility of defects generation. The crack initiation position of the 36MnVS4 connecting rod is random, scattered, and unstable, and the 36MnVS4 has higher gap sensitivity. Therefore, the 36MnVS4 connecting rod is more prone to produce quality defects in the fracture-split process. By changing the cross-section design, the outer edge of the joint surface is changed to arc-shaped, which can improve the fracture-split process of the 36MnVS4 connecting rod and reduce the processing defects. [ABSTRACT FROM AUTHOR]

The goal of this paper is to develop a highly accurate and efficient numerical method for the solution of a time-dependent partial differential equation with a piecewise constant coefficient, on a finite interval with periodic boundary conditions. The resulting algorithm can be used, for example, to model the diffusion of heat energy in one space dimension, in the case where the spatial domain represents a medium consisting of two homogeneous materials. The resulting model has, to our knowledge, not yet been solved in closed form through analytical methods, and is difficult to solve using existing numerical methods, thus suggesting an alternative approach. The approach presented in this paper is to represent the solution as a linear combination of wave functions that change frequencies at the interfaces between different materials. It is demonstrated through numerical experiments that using the Uncertainty Principle to construct a basis of such functions, in conjunction with a spectral method, a mathematical model for heat diffusion through different materials can be solved much more efficiently than with conventional time-stepping methods. [ABSTRACT FROM AUTHOR]

The continuing high level of demand for lightweight structural materials is the reason for the ever-growing interest in aluminum alloys. The main areas of application for aluminum alloys products are the aerospace and automotive industries. Production of profiles and structural elements from lightweight alloys gives possibility to reduce the curb weight of construction, which directly translates into among other reduction of fuel consumption and lower amount of generated exhaust gas. Determination of heat treatment and plastic working parameters to obtain the required mechanical properties of the manufactured products is a complex process that requires among others knowledge of the material behavior during the deformation process. To carry out the study the torsion plastometer STD 812 was used. On the basis of obtained results of the research the value of the yield stress, formability limit and the thermal effect of the deformed 7xxx series aluminum alloy were specified for different schemes and conditions of deformation. [ABSTRACT FROM AUTHOR]

The drill bit consists of: heavy rods, drill rods, drive rod, reducers and fittings. After a certain number of operating hours for a subassembly, some parts, more difficult to request, have an advanced state of wear, which makes it impossible to continue functioning of the respective assembly. In the tubular bases, the rods brought from the yard are identified, sorted and pre-directed. If they are clogged, they are cleaned with very long drills. For a good cleaning, the rods are left for a time in a room containing a solution of detergents and caustic soda. Then the rods are washed on the outside and inside, with water jets and rotary plastic fiber brushes. Afterwards, they are dried with hot air. After correcting their rectilinearity, with hydraulic presses, the actual control begins. Measure the length, outer diameter, wall thickness and, using the methods below, detect any operating defects. [ABSTRACT FROM AUTHOR]

Results are given for research to develop scientifically based process solutions to improve quality characteristics of rolled coils cooled in a two-stage Stelmor line ensuring effective metal microstructure and processing properties for wire and wire products. An increase in welding rod ductility is achieved by limiting the steel's strengthening element content, effective application of the boron to nitrogen ratio, and optimization of two-stage cooling, ensuring the formation of large ferrite grain size with rolling heat during isothermal soaking, thereby minimizing the formation of non-ductile structural components (bainite and martensite). For high-carbon wire rod used in the manufacture of concrete sleepers, it is necessary to achieve the fine pearlite structure of point 1 (GOST 8233-56) that is provided by alloying steel with boron, vanadium, and/or chromium, and also use of fan cooling. This structure is the optimum from the point of view of metal ductility and strength. [ABSTRACT FROM AUTHOR]

The problem of heat conductivity in arc and electron beam welding of rings and bars (parallelepiped) with a rectangular cross section with and without rapid cooling of the surface is investigated. The problem is solved analytically taking into account the dimensions of the component and welding technology (welding conditions and the sequence of making sections of the multilayer welded joint). A method is proposed for the determination of the welding conditions taking into account restrictions for the maximum temperature of heating the reference zone of the component. It is shown possible to replace the large-scale ring by a small-scale parallelepiped when investigating temperature fields in fusion welding. [ABSTRACT FROM PUBLISHER]

Experiments were carried out on 2 mm thick 304 stainless steel to verify the feasibility of Bypass Current Double Sided Arc Welding (BC-DSAW) for high-speed welding of thin plates. A high-speed camera was utilized to monitor the metal transfer process and the arc behaviour. The current density distribution of the MIG–TIG coupling arc was measured with the probe method. The bypass current increased the melting efficiency of the filler wire and reduced the heat input of the base metal; the current density at the arc centre was decreased by 30% with bypass current added. Owing to the preheating effect of the bypass arc on the filler wire, the metal transfer mode was altered from short circuiting transfer to globular transfer and the droplet growing time was shortened to increase the transfer frequency by 50%. [ABSTRACT FROM AUTHOR]

Replacement of copper during production of current-conducting busbars by aluminium clad with a thin layer of copper allows reducing metal intensity of products preserving the high electric conductivity. The technology of manufacture of coaxial copper-aluminium current-conducting rods using explosion welding and drawing was offered. The modes of heat treatment of rods after drawing were experimentally selected providing the required mechanical properties at a minimum number of forming intermetallics. The methods of calculation of sizes of initial billets providing obtaining the required geometric parameters of a product were described. The possibility of application of explosion reduction of billets instead of explosion welding is shown. [ABSTRACT FROM AUTHOR]

In the paper some results concerning the exact kinematics analysis of the mechanism of some sucker rod pumping units are presented. The analysis is realized using the method of the projection of the independent contours. The positional and cinematic parameters are determined in an analytical form depending on the angle of the driving cranks, using the powerful functions for symbolical calculus integrated in Maple program. Special attention was given to the variation of the acceleration of the end of the polished rod. Finally, some interesting simulation results in the case of the Lufkin pumping units: C-1280D-427-192, RM-1280D-427-192, M-1280D-427-192 and A-1280D-427-192 are presented. [ABSTRACT FROM AUTHOR]

Analysis of the particulates eliminated from typical mild steel 6010 welding rods during handling has been undertaken by scanning electron microscopy (SEM) with associated energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Upon breaking, the rod coating particles are released in the size range of 1-100 μm, which include over 60% of the particles that can be transported into the lower bronchial and alveolar regions. The composition of the particles is representative of the component of the flux coating. [ABSTRACT FROM AUTHOR]

The results of the pulsed-arc welding and the analysis of deposit welding technological features are discussed. It is established that pulse feeding ensuring electrode metal controllable transfer considerably influences the output performance of the welding process, decreasing 1.3-1.8 times expenditure of electric power. [ABSTRACT FROM AUTHOR]

The friction stir welding (FSW) process is capable of joining all aluminium alloys, especially 2xxx and 7xxx aerospace alloys, with good joint properties. Successful weld quality was obtained for a dissimilar joint 2050-T3 Al-Cu-Li alloy/7449-TAF Al-Mg-Zn-Cu alloy at 20 mm thickness thanks to pulsation of the advancing speed. This FSW dissimilar joint was post-weld heat treated: 2050-T8/7449-T79. The joint ultimate tensile strength (UTS) was 336 MPa, similar to a 7449 bead on plate with the same thickness. Moreover, the fracture location takes place in the 7449 heat affected zone (HAZ), the weakest point indicated by the microhardness profile. The 'pulsed' process induces an improved stirring based on alternation of dark and light bands, whose chemical composition is close to 2050 and 7449 respectively. [ABSTRACT FROM AUTHOR]

Friction stir welding (FSW) is a low distortion, high quality solid welding. There is no melting during the welding process, which results in improved welding quality. Ductile iron has the advantages of being low cost, of excellent castability, and of being good mechanically. Therefore, it is generally used in many structural engineering parts. In this study, ferritic ductile iron and low carbon steel were used to explore the qualities of dissimilar metal welding under different conditions. The FSW process, changes in the microstructure of the welding area and the mechanical properties of joints were explored. According to the research, we found that when dissimilar metal welding is conducted at 982 rev min-1 with a travelling speed of 72 mm min-1, flawless welding quality can be obtained if the stir rod rotates counterclockwise with carbon steel fixed in the advancing side and with ductile iron in the retreating side. FSW successfully provided defect free welds. However, fine pearlite and martensite structures appear in the stir zone, which result in mechanical property degradation of weldments. The stir zone in the weldments is very hard due to martensitic transformation. After heat treatment, the tensile strength improves, and the fracture site appears in the base metal of the carbon steel. However, the welding nugget is not completely filled when the stir rod directs ferritic ductile iron to the advancing side in the clockwise direction and carbon steel in the retreating side, which results in defects and lower welding quality. [ABSTRACT FROM AUTHOR]

Near-equiatomic NiTi S-shape rods of 400 mm long, which are used for surgical correction of scoliosis, are treated by nitrogen plasma immersion ion implantation (PIII) to reduce leaching of harmful Ni ions into the human body. To accomplish this purpose, a TiN barrier is created by Pill on the S-shape bars using different experimental setups. Our results reveal that the special quasi-direct-current Pill process can improve the efficacy of the process. In this technique, the reliability is improved by using a grounded Al housing and stainless steel mesh surrounding the specimen. The color uniformity is improved, and the maximum applicable voltage can be increased with reduced arcing and minimal changes in the shape memory effects of the materials. [ABSTRACT FROM AUTHOR]

The Green function theory was used to determine the temporal behavior of the two dimensional temperature distribution in a cylindrical rod placed in the focal axis of a cylinder of elliptical cross-section where in the other axis a flash lamp was mounted to pump the rod. The rod which was subjected in axial direction to a laser radiation to be amplified was assumed to be heated from the volume absorption of both the pump radiation and the laser radiation. Mathematical expression for the temperature distribution was obtained considering linear behavior of the rod, different focusing configuration of the pump beam and different radii of the laser radiation. As an illustrative example computation was carried out on a Ruby rod. [ABSTRACT FROM AUTHOR]

The article discusses the special features of welding steels by pulsed electrode wire feed. It states that it is an expeditious method of managing the formation of the welded joint in carbon dioxide welding in different spatial positions with short-circuiting of the welding gap of steels with a wide range of thickness. It notes that the major effects found in welding with it is the large widening of the range of the stable conditions of the procedure.

We synthesize monodisperse selenium (Se) colloidal rods, and the suspensions exhibit the smectic phase at a particle volume fraction () of 0.28. Side-by-side rod clustering occurs at > 0.04. Cluster-size distributions and persistence times are determined for various . In dense suspensions ( > 0.1), individual rods reveal characteristic fundamental motions, e.g., reptation and synchronized rotation. Mean-square displacements of the rods suggest a cage trapping and escape. Estimated translational and rotational diffusion coefficients show a large difference from predictions by computer simulations. [ABSTRACT FROM AUTHOR]

Tetragonal (t-)ZrO2 rods and spheres were prepared by simple and time-saving low-temperature synthesis and characterized by X-ray diffraction, Raman spectroscopy and scanning electron microscopy. The morphology of the product can be changed from rods to spheres by changing the reaction conditions slightly. The t-ZrO2 rods (0.5–0.1mm approximately) were obtained by topotactic reaction. The work illustrates the utility of Raman spectroscopy as a powerful characterization tool when XRD is not able to conclusively identify the phases. [Copyright &y& Elsevier]

Recent studies report that exposure to manganese (Mn), an essential component of welding electrodes and some steels, results in neurotoxicity and/or Parkinson's disease (PD) in welders. This "state-of-the-science" review presents a critical analysis of the published studies that were conducted on a variety of Mn-exposed occupational cohorts during the last 100 yr, as well as the regulatory history of Mn and welding fumes. Welders often perform a variety of different tasks with varying degrees of duration and ventilation, and hence, to accurately assess Mn exposures that occurred in occupational settings, some specific information on the historical work patterns of welders is desirable. This review includes a discussion of the types of exposures that occur during the welding process - for which limited information relating airborne Mn levels with specific welding activities exists - and the human health studies evaluating neurological effects in welders and other Mn-exposed cohorts, including miners, millers, and battery workers. Findings and implications of studies specifically conducted to evaluate neurobehavioral effects and the prevalence of PD in welders are also discussed. Existing exposure data indicate that, in general, Mn exposures in welders are less than those associated with the reports of clinical neurotoxicity (e.g., "manganism") in miners and smelter workers. It was also found that although manganism was observed in highly exposed workers, the scant exposure-response data available for welders do not support a conclusion that welding is associated with clinical neurotoxicity. The available data might support the development of reasonable "worst-case" exposure estimates for most welding activities, and suggest that exposure simulation studies would significantly refine such estimates. Our review ends with a discussion of the data gaps and areas for future research. [ABSTRACT FROM AUTHOR]

The article offers information on the investigations carried out to study the effects of welding materials and shielding gas composition in the reduction of spatter generation during gas shielded arc welding. It focuses on the mode of spatter formation, and the reduction of spatter by the use of a mixed shielding gas. It also focuses on the effects of wire composition upon the quantity of spatter generation during gas shielded arc welding using solid wire and flux cored wires.

The article offers information on the welding methods to reduce the quantity of fume formed during gas shielded arc welding with a view to prevent hazards to health. It focuses on the mechanisms of fume generation during arc welding, the fume concentration in the welding operation environment, and the chemical compositions of the welding fume. It also focuses on an investigation into the effects of various factors such as wire composition upon the quantity of fume generated during welding.

The article focuses on the process of controlling the transfer of electrode metal in welding by the application of the pulsed feed of welding wire in order to reduce the splashing of electrode metal. It mentions that the splashing of electrode metal in carbon dioxide welding increases the consumption of electrode wire and gas, leading to an increase in the cost of welded structures. It describes how the pulsed feed of the electrode wire results in a large decrease of the degree of splashing.

Examines the role of inertia tensor, static moment and mass in perceiving the length and heaviness of hand-wielded rods. Design of the rods; Correlation between perceived rod length on inertia tensor; Relation between static moment and the eigenvalues of the inertia tensor.

The paper gives recommendations on improvement of coated electrode manufacture through the entire sequence of technological process, including direct grinding of coating components, preparation of liquid glasses and electrode rods, coating mixture preparation, electrode extrusion and heat treatment. [ABSTRACT FROM AUTHOR]

The article discusses the investigation on welding method called percussion capacitor discharge welding. It says that this process can be used in producing welded joints on body component-rod type made of dissimilar materials and for forging effect. It mentions the use of magnetic pressure to enable heating and high-intensity deformation during a discharge of a capacitor bank. It also cites several advantages of the method such as cleaned welded surfaces due to electric erosion mechanism.