DC SQUID based on the mesoscopic multiterminal Josephson junction

A theory is offered for a novel device, mesoscopic four-terminal SQUID. The studied system consists of a mesoscopic four-terminal junction, one pair of terminals of which is incorporated in a superconducting ring and the other one is connected with a transport circuit. The nonlocal weak coupling between the terminals leads to effects of phase dragging and magnetic flux transfer. The behaviour of a four-terminal SQUID, controlled by the external parameters, the applied magnetic flux and the transport current is investigated. The critical current and the current voltage characteristics as functions of magnetic flux are calculated. In the nonlocal mesoscopic case they depend not only on the magnitude of the applied flux but also on its sign, allowing measurement of the direction of the external magnetic field.Comment: 11 pages, 4 figures, presented at the EUCAS 2001 conferenc

Selection of cemented carbide turning tools using EMF and optimization criteria

Tool life and quality of surface finish of the workpiece influence production rate and production cost. Cemented carbide tools have found wide application in the production arena of Bangladesh. In the absence of any testing facility in the country for the selection of cost-effective tools, poor quality carbide tools are frequently imported. A testing method and a selection criteria were developed for testing carbide tools of different shapes and sizes and for selecting the most cost-effective tool. For each tool cutting tests were performed to generate tool life data under different cutting conditions. Mild steel served as the work material. The relationship between tool life and cutting speed was developed using a curve-fitting software on a PC. From these relationships the values of the constants of the Taylor’s equation were determined. The cost equation was then derived for each tool for a given amount of work in a cutting speed range. Finally, the most cost-effective tool was selected on the basis of the relative location of the cost curves of the tools tested

Multi-criteria optimization in end milling of AISI D2 hardened steel using coated carbide inserts

This paper proposes a multi-criteria optimization technique using the mathematical models developed by the response surface methodology (RSM) for the target responses combined with desirability indices for the determining the optimum cutting parameters in end milling of AISI D2 hardened steels. Different responses may require different targets either being maximized or minimized. Simultaneous achievement of the optimized (maximum or minimum) values of all the responses is very unlikely. In machining operations tool life and volume metal removed are targeted to be maximized whereas the machined surface roughness need to be at minimum level. Models showing the combined effect of the three control factors such as cutting speed, feed, and depth of cut are developed. However, a particular combination of parameter levels appears to be optimum for a particular response but not for all. Thus adoption of the method of consecutive searches with higher desirability values is found to be appropriate. In this study the desirability index reaches to a maximum value of 0.889 after five consecutive solution searching. At this stage, the optimum values of machining parameters - cutting speed, depth of cut and feed were determined as 44.27 m/min, 0.61 mm, 0.065 mm/tooth respectively. Under this set condition of machining operations a surface roughness of 0.348 μm and volume material removal of 7.45 cm3 were the best results compared to the rest four set conditions. However, the tool life would be required to compromise slightly from the optimum value

Cost Model for end-milling of AISI D2 tool steel

In this research paper, user-friendly and accurate mathematical model for estimating the cost of end-milling of AISI D2 tool steel using Polycrystalline Cubic Boron Nitride (PCBN) cutting tool inserts is developed. Initially, the different components of machining cost were identified, followed by establishment of equations to determine their values. Then, the required experimental and non-experimental data were collected and the bottom-up approach was adopted for evaluating the cost of machining corresponding to each of fifteen experimental runs. The Response Surface Methodology (RSM) was used to develop the model in which the cost of machining is given as a function of the machining parameters; cutting speed, feed per tooth, and depth of cut, and expressed in Ringgit Malaysia per cubic cm (RM per cm)3. Analysis of Variance (ANOVA) was utilized to check the adequacy of the developed model. The developed model was found to be statistically adequate

Multi-Terminal Superconducting Phase Qubit

Mesoscopic multi-terminal Josephson junctions are novel devices that provide weak coupling between several bulk superconductors through a common normal layer. Because of the nonlocal coupling of the superconducting banks, a current flow between two of the terminals can induce a phase difference and/or current flow in the other terminals. This "phase dragging" effect is used in designing a new type of superconducting phase qubit, the basic element of a quantum computer. Time-reversal symmetry breaking can be achieved by inserting a pi-phase shifter into the flux loop. Logical operations are done by applying currents. This removes the necessity for local external magnetic fields to achieve bistability or controllable operations.Comment: 7 pages, 3 figure

MANAGEMENT STATUS OF MACKAREL (RASTRELLIGER SP.) RESOURCES IN THE FISH RESOURCES DOMAIN OF REMBANG DISTRICT, CENTRAL JAVA PROVINCE OF INDONESIA, AS A PART OF ECOSYSTEM APPROACH OF FISHERIES MANAGEMENT

Mackerel is an economically high and dominant fish caught in the waters of Rembang District. Its production volume is the third largest in 2017, by 2,013 tons. Mackerel is commonly caught using a small pelagic – one boat operated purse seine with a 30 GT boat down. Intensive fishing efforts will endanger the population of this fish, so management is needed so that fish resources can be sustainable. The study was conducted in Rembang District to see the status of mackerel (Rastrelliger sp.) resource management in the domain of fish resources with an ecosystem approach. It lasted from December 2018 to February 2019. It employed a survey method. The indicators used in the domain of fish resource are standard CPUE, trends in fish size, proportion of juvenile fish caught, catch species composition, range collapse of fish resources, and ETP species. The results showed that standard CPUE, trends in fish size, catch species composition, proportion of juvenile fish caught, and ETP species are in good condition with a score of 3 (green modeling flag). While the range collapse of fish resources is in a moderate condition, with a score of 2 (yellow modeling flag). The composite score of 97 shows that management status of Mackerel resources in the domain of fish resource in Rembang District is in very good condition (dark green flag modeling)

Prediction of surface roughness in hard milling of AISI D2 tool steel

This paper presents a study of the development of a surface roughness model in end milling of hardened steel AISI D2 using PVD TiAIN coated carbide cutting tool. The hardness of AISI D2 tool lies within the range of 56-58 HRe. The independent variables or the primary machining parameters selected for this experiment were the cutting speed, feed, and depth of cut. First and second order models were developed using Response Surface Methodology (RSM). Experiments were conducted within specified ranges of the parameters. Design-Expert 6.0 software was used to develop the surface roughness equations as the predictive models. Analysis of variance (ANOVA) with 95% confidence interval has indicated that the models are valid in predicting the surface roughness of the part machined under specified condition

Development of mathematical cost model for room temperature end-milling of AISI D2 tool steel

In this research paper, reliable mathematical model for estimating the cost of room temperature end-milling of AISI D2 tool steel using TiAlN coated carbide tool inserts is developed. Initially, the different components of machining cost were identified, followed by establishment of equations to determine their values. Then, the required experimental and non-experimental data were collected and the bottom-up approach was adopted for evaluating the cost of machining corresponding to each of fifteen experimental runs. The Response Surface Methodology (RSM) was used to develop the model in which the cost of machining is given as a function of the machining parameters: cutting speed, feed per tooth, and depth of cut, and expressed in RM per cm3. ANOVA output was utilized to check the adequacy of the developed model. The developed model was found to be statistically adequate and this was confirmed by the small prediction errors made by the mode

Surface roughness models for end milling titanium alloy TI-6AL-4V under room temperature and preheated machining

This paper presents an approach in developing the first and second-order surface roughness models at 95% confidence level for end milling of titanium alloy Ti-6AI-4V using PCD inserts. The surface roughness models developed were for room temperature machining and preheated experiments. The cutting parameters for room temperature machining were the cutting speed, axial depth of cut, and feed while those for preheated machining experiments were cutting speed, feed, and preheating temperature. Vertical Machining Centre (VMC) was used for conducting the end milling operations using PCD inserts. High frequency induction heating was utilized for preheated experiments. Surface roughness values were measured using a surface roughness measuring instrument Mitutoyo Surftest Model SV-500. Design expert package software was used to establish the surface roughness models and the adequacy of the models were verified using analysis of variance at 95% of confidence interval

Development of mathematical cost model for preheated end-milling of AISI D2 tool steel

Mohamed Elhadie1, A. N. Mustafizul Karim1, A. K. M. Nurul Amin1 Department of Manufacturing and Materials Engineering International Islamic University Malaysia, Gombak, Kuala Lumpur 53100, Malaysia M. A. Lajis2 Faculty of Mechanical and Manufacturing Engineering Universiti Tun Hussein Onn Malaysia, Batu Pahat, Johor Bahru 86400, Malaysia Abstract In this research paper, reliable mathematical model for estimating the cost of preheated end-milling of AISI D2 tool steel using TiAlN coated carbide tool inserts is developed. Initially, the different components of machining cost were identified, followed by establishment of equations to determine their values. Then, the required experimental and non-experimental data were collected and the bottom-up approach was adopted for evaluating the cost of machining corresponding to each of fifteen experimental runs. The Response Surface Methodology (RSM) was used to develop the model in which the cost of machining is given as a function of the machining parameters; cutting speed, feed per tooth, and preheating temperature, and expressed in RM per cm3. ANOVA output was utilized to check the adequacy of the developed model. The developed model was found to be statistically adequate and this was confirmed by the small prediction errors made by the model. Keywords: machinin