Research of the influence of bias voltage on the structure and residual stress in Ta/W coatings applied on a copper substrate by inverted magnetron

This paper presents the results of studying the effect of the bias voltage on a copper tube substrate on the texture and residual stresses in 4-layer Ta/W/Ta/W coatings deposited with an inverted magnetron. It is shown that, in contrast to monolayer coatings of Ta and W, in which residual stresses exceeding 2 GPa are formed on the substrate at high voltages on the substrate, stress relaxations occur in the 4-layer coating in alternating layers differing in LTEC values and in the outer W-layer of stress practically absent.

Experimental Modeling of Large Diameter Holes Based on Materials of Bronze Age Stone Axes

In the Urals, there are more than a hundred products with large-diameter holes, some of which are made using a copper tube. Experiments on hollow drilling in the expedition of S. A. Semenov have shown great complexity of this method. In experiments on drilling it was planned to identify labor costs for the manufacture of copper tube, and also reveal various aspects of drilling techniques. The article presents the results of experiments on drilling different types of stone (soapstone, marble, serpentine and jade) with a copper tube. Experiments have shown that drilling with a brace is 1.5 times more effective than drilling with a borer. And using a copper tube as a drill increased the speed of making holes by 4–7 times. It also turned out that the abrasive used is very important for drilling efficiency. The most effective abrasive was emery, whose deposits are known in the southern Urals. The results obtained allow the authors to establish with great accuracy what drills and with application of what equipment stone axes of Bronze Age were drilled. A comparison of the experimental drills with bronze age drills shows that drilling with a copper tube was often, but not always, performed using a special machine tool. Labor-intensive making stone axes with large diameter holes especially made of strong row materials attest about high social status of their owners.

Manufacturing and Characterization of Tube-Filled ZA27 Metal Foam Heat Exchangers

This study investigates the heat transfer performance of a novel ZA27 metal foam heat exchanger. An open-celled metal foam is combined with a thin-walled copper tube in a single-step casting process. The heat transfer between two separated water streams flowing through the copper tube and foam, respectively, is measured and compared to an equivalent shell tube heat exchanger arrangement. Heat transfer enhancement of up to 71% and a heat transfer rate exceeding 30 kW are observed and attributed to the increased surface area of the metallic foam. However, overall performance was limited by the inefficient heat transfer between the internal mass stream and the copper tube.

Solar Dryer with Inbuilt Thermal Energy Storage Device

In the solar dryer is a device in which drying the substance with the help of only solar energy. In this system we observe that the time take to perform the operation high and the effectiveness is very low, and availability also low. With the help of thermal energy storage device, we update the solar dryer. In solar dryer with thermal energy storage device. The energy used is solar as well as thermal energy, availability is increase and effectiveness is also increase. When the blower switch is on the atmospheric air is drawn in the copper tube, surrounding of the copper tube is hot water is available. Hence the hot water is available the atmospheric air is exchange the heat the air get hot this hot air is hot water is move to container (vessel). Then the temperature of the container (vessel) increase. Hence the time take for the perform operation is decrease.

Investigation of the explosive type on the high strain forming of OFHC copper tube

The paper computationally investigates the explosive forming of the oxygen-free high thermal conductivity (OFHC) copper tube subjected to five different explosives. To investigate the effect of explosive type on the formability of OFHC copper tube, commonly used explosives, including C-4, TNT, HMX, Comp-B, and PBXN, was compared by using the finite element method. To verify the developed finite element model (FEM), the explosive forming experiments were carried out by using C-4. In the simulations, Coupled-Eulerian-Lagrangian (CEL) method to model the large deformations, Jones-Wilkins-Lee (JWL) equations of state (EOS) to define the explosive properties and Johnson-Cook (J-C) strength and damage models to specify the metal’s mechanical behavior were utilized. Besides, Hillerborg’s fracture energy was calculated with the Charpy impact test results and given as input to the FEM. The results of FEM were compared and verified using the results of explosive forming tests considering the mesh density and friction coefficient. The simulations revealed that the explosive type affected both the final shape and also the strain rate of the copper tube. When the simulation results for C-4 was taken as reference, HMX and PBX-N increased the strain rate as 110%, roughly. However, Comp-B and TNT reduced the strain rate by nearly 10% and 22%, respectively. Also, the explosive type changed the final hardness of the metal. OFHC Copper had the lowest hardness (112.7 HV) when the simulations were conducted with TNT. In contrast, the highest hardness value (129.5 HV) was reached when HMX was used in the simulations. In addition, simulations put forth that Hillerborg’s fracture energy criteria could be used in the explosive simulations to predict the damage on the metals.