A new electric field mill array with each of the mill’s rotor controlled precisely by a GPS module:Equipment and initial results

We have newly designed an electrostatic sensor,called an electric field mill(EFM),to simplify the estimation of the charge position and charge amount transferred by lightning discharges.It is necessary for this remote estimation of the transferred charge to measure electric field changes caused by charge loss at the time of a lightning strike at multiple locations.For multiple-station measurement of electric field changes,not only speed but also phase for exposure and shielding of the sensing plates inside each EFM of the array should be synchronized to maintain the sensitivities of the deployed instruments.Currently,there is no such EFM with specified speed and phase control performance of the rotary part.Thus,we developed a new EFM in which the rotary mechanism was controlled consistently to within 3%error by a GPS module.Five EFMs had been distributed in the Hokuriku area of Japan during the winter season of 2022-2023 for a test observation.Here we describe the design and a simple calibration method for our new EFM array.Data analysis method based on the assumption of a simple monopole charge structure is also summarized.For validation,locations of assumed point charges were compared with three-dimensional lightning mapping data estimated by radio observations in the MF-HF bands.Initial results indicated the validity to estimate transferred charge amounts and positions of winter cloud-to-ground lightning discharges with our new EFM array.

Deformation behaviors of magnesium alloy AZ31 sheet in cold deep drawing

To investigate how the popular magnesium alloy AZ31 sheet(aluminum 3%,zinc 1%)behaves in cold working,deep drawing experiments at room temperature,along with finite element(FE)simulation,were performed on the cold forming sheet of the AZ31 alloy after being annealed under various conditions.The activities were focused on the fracture pattern,limit drawing ratio(LDR),deformation load,thickness distribution,anisotropic effect,as well as the influences of the annealing conditions and tool configuration on them.The results display that punch shoulder radius instead of die clearance,has much influence on the thickness distribution.The anisotropy is remarkable in cold working,which adversely impacts the LDR.The fracture often happens on the side wall at an angle to axis of the deformed specimen.The results also imply that the LDR for the material under present experimental conditions is 1.72,and annealing the material at 450 ℃ for 1 h may be preferable for the cold deep drawing.

FEM Modeling of Crack Propagation in a Model Multiphase Alloy

In this paper, several widely applied fracture criteria were first numerically examined and the crack-tip-region Jntegral criterion was confirmed to be more applicable to predict fracture angle in an elastic-plastic multiphase material. Then, the crack propagation in an idealized an elastic-plastic finite element method. The variation dendritic two-phase AI-7%Si alloy was modeled using of crack growth driving force with crack extension was also demonstrated. It is found that the crack path is significantly influenced by the presence of α-phase near the crack tip, and the crack growth driving force varies drastically from place to place. Lastly, the simulated fracture path in the two-phase model alloy was compared with the experimentally observed fracture path.

Model of Maintenance Planning Based on Trend of Machines Failures with Two Priorities

In this article we are discussing the suggestion of planning maintenance in such situation that we have failures in database of failures and maintenance registered also according to type of failure— priority or non-priority. We are assuming that maintenance must be mainly oriented on avoiding major failures of machines. The effect of maintenance manifests with delay and is dependent on development of failures. We express this problem as linear programming task that is solvable with Solver-extension of application Excel. We demonstrate the suggested solution on example of failures of machines between years 2010 and 2012.

Fundamental Concept of Interdiffusion Problems

In accordance with the definition of diffusivity, the origin of coordinate system of the original diffusion equation is set at a point in the solvent material. Kirkendall revealed that Cu atoms, Zn atoms and vacancies move simultaneously in the interdiffusion region. This indicates that the original diffusion equation is a moving coordinate system for the experimentation system outside the diffusion region. The diffusion region space which means vacancies and interstices among atoms plays an important role in the diffusion phenomena. The theoretical equation of the Kirkendall effect is reasonably obtained as a shift between coordinate systems of the diffusion equation. The situation is similar to the well-known Doppler effect in the wave equation. Boltzmann transformed the original diffusion equation of a binary system into the nonlinear ordinary differential equation in accordance with the parabolic law. In the previous works, the solutions of the diffusion equation transformed by Boltzmann were analytically obtained and we found that the well-known Darken equation is mathematically wrong. In the present study, we found that the so-called intrinsic diffusivity corresponds in appearance to the physical solution obtained previously. However, the intrinsic diffusivity itself conceived in the diffusion research history is essentially nonexistent.

Effects of Bearing Type on Seismic Response of Small Base Isolation System Using Friction Bearings

In this study, dynamic characteristics of the small base isolation system using new friction bearings are investigated by excitation experiment, and compared to other one using previous bearings. Peak amplitude of the acceleration response waves on the small base isolation system is decreased to about 10%-25% compared to the input waves. Also root mean square amplitude is decreased to about 10%-40%. In case of the ball embedded a cylindrical sponge, the new bearing, the damping ratio increases with increasing width of the cylindrical sponge. The natural frequency does not change. On the other hand, in case of the marble plate that is previous bearing, the damping ratio increases with increasing curvature radius of the marble plate, the natural frequency also increases. Therefore, the small base isolation system using new friction bearing provides better performance. The responses of the base isolation system indicate nonlinier effects by friction force.

New Analytical Method of Interdiffusion Problems

The nonlinear diffusion equation for a binary system interdiffusion was analytically solved in the previous work. The theoretical relation of Kirkendall effect was also derived in the previous work. These new results have not yet been concretely applied to actual diffusion problems. In the present work, it is revealed that the previous results reproduce the experimental concentration profile by taking account of the movement of diffusion region space. It is thus actually confirmed that any problems of binary system interdiffusion can be solved by the new analytical method if even diffusivities of self-diffusion and impurity diffusion in the materials concerned are given. The method for solving interdiffusion problems of many elements system, which is extremely important for the development of new useful materials, is also reasonably discussed. Further, it is revealed that the concept of intrinsic diffusion is unsuitable for the diffusion theory. The fundamental theory of diffusion discussed here will be useful for analyzing actual diffusion problems in future.

Blockchain in Smart Grid for Sustainable Management of Environmental Resources Usage

Blockchain is a distributed database that is shared among the nodes of a computer network.Blocks have certain storage capacity and,when filled,they are closed,and linked to the previously filled block,forming a chain.Blockchains are typically managed by a peer-to-peer method where nodes collectively adhere to a consensus algorithm protocol to add and validate new transaction blocks.The author makes a review of Blockchain applications in different areas,considerable challenges,her own experience with Blockchain in Smart Grid and other researchers`contributions.The paper presents the first stage of project“Smart Grid for Sustainable Management of Environmental Resources Usage”-describing Managed Objects classes for selected functional areas of Blockchain life cycle:Configuration,Security,and Performance.The author uses the life cycle of telecommunication networks as a reference.The models are designed for user interface developers,university professors,and students.

Martensitic stabilization and defects induced by deformation in TiNi shape memory alloys

Martensitic stabilization caused by deformation in a TiNi shape memory alloy was studied.Special attention was paid to the deformed microstructures to identify the cause of martensitic stabilization.Martensitic stabilization was demonstrated by differential scanning calorimetry for the tensioned TiNi shape memory alloy.Transmission electron microscopy revealed that antiphase boundaries were formed because of the fourfold dissociation of [110]B19＇ super lattice dislocations and were preserved after reverse transformation due to the lattice correspondence.Martensitic stabilization was attributed to dislocations induced by deformation,which reduced the ordering degree of the microstructure,spoiled the reverse path from martensite to parent phase compared with thermoelastic transformation,and imposed resistance on phase transformation through the stress field.

A MPCC-NLP Approach for an Electric Power Market Problem

The electric power market is changing-it has passed from a regulated market, where the government of each country had the control of prices, to a deregulated market economy. Each company competes in order to get more cli.e.nts and maximize its profits. This market is represented by a Stackelberg game with two firms, leader and follower, and the leader anticipates the reaction of the follower. The problem is formulated as a Mathematical Program with Complementarity Constraints (MPCC). It is shown that the constraint qualifications usually assumed to prove convergence of standard algorithms fail to hold for MPCC. To circumvent this, a reformulation for a nonlinear problem (NLP) is proposed. Numerical tests using the NEOS server platform are presented.

Deformation Mechanism and Stabilization of Martensite in TiNi Shape Memory Alloy

The deformed microstructures of a TiNi shape memory alloy were investigated in present study to clarify the deformation mechanism.It is found that the stress-strain curve was divided into three stages based on the deformation modes.The cause of martensitic stabilization effect was also interpreted by paying special attention to the deformed microstructures.Transmission electron microscopic examination revealed that at the early stage of deformation martensitic reorientation and compound twinning relieved some of the elastic strain energy stored in martensite,and this contributes to the martensitic stabilization effect.However,when deformation strain became larger,the density of dislocations increased correspondingly.Antiphase boundaries were also found.The degree of ordering was therefore decreased due to dislocations and antiphase boundaries.So disordering was another cause of martensitic stabilization effect.In the middle stage of deformation martensitic stabilization was attributed to the two reasons above.

Numerical Study of Interaction of Propagated Shock with Boundary Layer Behind Contact Surface in Ducts

The interactions of the shock with the boundary layer of the cold gas behind the contact in many different conditions.i.e. three kinds of test gases and three kinds of sound speed ratios across the contact,were explored by numerical study.The trajectories of the transmitted shock in cold gas flow and the development of shock bifurcation in the process of interaction with boundary layer are illustrated by many kinds of figures(e.g.the time-distance diagrams of the acoustic impedance contours on the axis,the pressure and density contours and the static pressure distributions on the axis.).

Numerical Study of the Effects of the Secondary Diaphragm and Contact Surface in Expansion Tubes

The interaction of the shock reflected at a secondary diaphragm with the primary contact in six cases, i.e. the strengths and shapes of the contact surface are different, were explored by numerical study. The influences of the strength and shape of the contact on the developing wave pattern and the quality of the test gas are illustrated by many kinds of figures (e.g. the time-distance diagrams of the acoustic impedance contours on the axis, the acoustic impedance contours, and the time histories of pilot and static pressures).

Classification methodology for spare parts management combining maintenance and logistics perspectives

Spare parts management is a function of maintenance management that aims to support maintenance activities,giving real-time information on the available quantities of each spare part and adopting the inventory policies that ensure their availability when required,minimizing costs.The classification of spare parts is crucial to control the vast number of parts that have different characteristics and specificities.Spare parts management involves mainly two areas,maintenance and logistics.Therefore,the integration of both input information is recommended to make decisions.This paper presents a multicriteria classification methodology combining maintenance and logistics perspectives that intends to differentiate and group spare parts to,subsequently,define the most appropriate stock management policy for each group.The methodology was developed based on a case study carried out in a multinational manufacturing company and is intended to be included in its computerized maintenance management system to support decision-making.