Thin Iron Plates Research Articles

Vibration control device having variable moment of inertia by MR fluid inside a flywheel

An inertia effect is proportional to acceleration and mass as a negative force, keeps own situation of a body during movement under inertia law. It is obvious that the inertia mass effect is available to decrease own natural frequency and arise anti-resonance which can be shut down vibration in a special case. In previous paper the authors updated a vibration control device which was having variable moment of inertia by Magneto-Rheological fluid inside a flywheel. Ferrite particles of the MR fluid are clustered when magnetic field is applied by 8 electromagnets to the flywheel. It was clear that the inertia mass effect was varied as higher current, and vibration control effect under the earthquake was confirmed numerically and experimentally. If inertia mass effect can be switched depending on anti-resonance, vibration may be able to be suppressed under the earthquake. Recently some researchers focus reinforcement learning to decrease vibration. Therefore, to switch mass inertia effect, reinforcement learning is adopted. In this paper firstly the vibration control device with thin iron plate attached inside the flywheel is updated from prototype in order to get more inertia effect. Secondly, Deep Deterministic Policy Gradient (DDPG) which is a part of reinforcement algorithm is adopted in order to decrease vibration by inertia mass effect, and vibration tests of one degree-of-freedom were carried out.

The Yarm Helmet

THE YARM HELMET, unearthed in the 1950s by workmen at Yarm (North Yorkshire, England), is a composite construction ‘crested’ helmet of riveted, undecorated, thin iron plates. Without close parallel at the time it was found, it could not be confidently attributed to a specific date or culture. This paper records, analyses and reassesses the helmet, demonstrating that it is not a later copy, but an original 9th–11th-century helmet, comparable with the helmet at Gjermundbu (Norway). Its materials and construction speak to the growing pragmatism of arms and armour production, which was necessary to supply the increasing numbers of armed warriors present in this period.

Numerical modeling and characterization of the laser–matter interaction during high-power continuous wave laser perforation of thin metal plates

The phenomena occurring during laser–metal interaction depend on a variety of parameters such as laser wavelength, intensity, and thermophysical and optical properties of the irradiated material. This work comprises a detailed study of the perforation process of thin iron and steel plates under CW laser radiation at a wavelength of 1.07 μm. Experiments were carried out over a wide range of intensities between 0.1 and 100 kW/cm2, and with beam radii in the millimeter and centimeter range. Additionally, we describe a method applying contact-free radiative temperature measurements, which allows the measurement of melt-through times without an exact knowledge of the plate's spectral surface emissivity. A detailed numerical model is presented and employed to analyze, interpret, and predict data gathered from the experiments. The model is shown to produce accurate predictions and is in good agreement with experimental data. Furthermore, our results indicate that in the investigated regime perforation is governed by gravitational and surface forces. Based on this hypothesis, a criterion for the onset of the perforation explaining the observed local minimum in the perforation time versus beam radius curve is presented.

Flexible superior electrode architectures based on three-dimensional porous spinous α-Fe2O3 with a high performance as a supercapacitor.

Flexible supercapacitors have recently attracted increasing attention as they show unique promising advantages, such as flexibility and shape diversity, and they are light-weight and so on. Herein, we designed a series of 3D porous spinous iron oxide materials synthesized on a thin iron plate through a facile method under mild conditions. The unique nanostructural features endow them with excellent electrochemical performance. The electrochemical properties of the integrated electrodes as active electrode materials for supercapacitors have been investigated using different electrochemical techniques including cyclic voltammetry, and galvanostatic charge-discharge in Na2SO4 and LiPF6/EC : DEC electrolyte solutions. These integrated electrodes showed high specific capacitance (as high as 524.6 F g(-1) at the current density of 1 A g(-1)) in 1.0 M Na2SO4 (see Table S1). Moreover, the integrated electrodes also show high power densities and high energy densities in a LiPF6/EC : DEC electrolyte solution; for example, the energy densities were 319.3, 252.5, 152.1, 74.13 and 38.6 W h kg(-1) at different power densities of 8.81, 21.59, 56.65, 92.09 and 152.64 kW kg(-1), respectively. Additionally, the flexible superior electrode exhibited excellent stability with capacitance retention of 92.9% after 5000 cycles. Therefore, such flexible integrated devices might be used in smart and portable electronics.

Construction and characterisation of a modular microfluidic system: coupling magnetic capture and electrochemical detection

This work presents the fabrication and characterisation of a versatile lab-on-a-chip system that combines magnetic capture and electrochemical detection. The system comprises a silicon chip featuring a series of microband electrodes, a PDMS gasket that incorporates the microfluidic channels, and a polycarbonate base where permanent magnets are hosted; these parts are designed to fit so that wire bonding and encapsulation are avoided. This system can perform bioassays over the surface of magnetic beads and uses only 50 μL of bead suspension per assay. Following detection, captured beads are released simply by sliding a thin iron plate between the magnets and the chip. Particles are captured upstream from the detector and we demonstrate how to take further advantage of the system fluidics to determine enzyme activities or concentrations, as flow velocity can be adjusted to the rate of the reactions under study. We used magnetic particles containing β-galactosidase and monitored the enzyme activity amperometrically by the oxidation of 4-aminophenol, enzymatically produced from 4-aminophenyl-β-d-galactopyranoside. The system is able to detect the presence of enzyme down to approximately 50 ng mL−1.

Gating system design to cast thin wall ductile iron plates

The present study describes the development of a horizontal and a vertical mould designed to produce thin ductile iron plates of 1·5–4 mm thickness. Both moulds used a non-pressurised configuration. The horizontal mould design was based on empirical rules, while the vertical mould was based on numerical simulations of fluid flow and thermal field, carried out using the software NovaFlow&Solid. The aim of both designs was to produce sound ductile iron plates that were large enough to make tensile test samples. The results show that the adoption of empirical rules and a non-pressurised configuration were not enough to guarantee proper filling. An optimised design was obtained through the use of mathematical modelling.

3D computer simulation of melt flow and heat transfer in the lost foam casting process

AbstractA new mathematical model has been developed to simulate mould filling in the lost foam casting process, using the finite difference method. The simulation of molten flow and track of free surfaces is based on the SOLA‐VOF numerical technique. An algorithm was developed to calculate the gas pressure of the evaporated foam during the mould filling. The effect of backpressure on the filling behaviour was modelled with an experimental function by adding three‐dimensions 3DVOF functions. In order to verify the computational results, a thin grey iron plate was poured into a transparent mould. Cavity filling, foam depolymerization and gap formation were recorded with a 16mm high‐speed camera. A good agreement was achieved for simulation results of filling sequences with those from experiments. Copyright © 2003 John Wiley & Sons, Ltd.

The LHCb hadron calorimeter

Abstract The Hadron Calorimeter (HCAL) is designed for the LHCb experiment. The main purpose of the detector is to provide data for the L0 hadron trigger. The HCAL is designed as consisting of two symmetric movable parts of about 500 ton in total getting in touch in operation position without non-instrumented zones. The lateral dimensions of an active area are X=8.4 m width, Y=6.8 m height, and is distanced from the interaction point at Z=13.33 m . Both halves are assembled from stacked up modules. An internal structure consisting of thin iron plates interspaced with scintillating tiles has been chosen. Attention is paid to optimize the detector according to the requirements of the experiment, reducing the spending needed for its construction. Different construction technologies are being discussed. The calorimeter properties have been extensively studied with a variety of prototype on the accelerator beam. The calibration with a radioactive source and module-0 construction experience is discussed.

Investigation for the design of electromagnet for the levitation of thin iron plate.

The thin iron plate is needed to be transported without the degradation of the quality of surface, and magnetic levitation technology is one of the solutions to satisfy these requirements. Magnetic saturation in the objective, however, is a severe problem for the levitation of the thin iron plate. Design and evaluation method of the electromagnet is studied to avoid the saturation. In this paper, the shape of the electromagnet is studied to design the electromagnet shape for the levitation of the thin iron plate. The magnetic saturation occurs in the iron plate especially when plate is very thin. Therefore, the preferable shape of electromagnet should be investigated to secure the large cross sectional area of flux path in the plate. The authors suggest the evaluation factor. The evaluation factor of magnet shape for thin iron plate is studied experimentally. In conclusion, the evaluation factor of magnet shape, however, is not sufficient to decided the optimum shape of electromagnet for thin plate levitation. Thus the another evaluation factor is the electric power consumption. The design of the electromagnet shape for levitation of the thin iron plate is possible by evaluation factor of magnet shape and the power consumption.

Transportation technique for magnetically levitated thin iron plates

In motorcar factories, there is a growing need for a high surface quality of iron plate. Conventional contact suspensions, such as the roller or arm types, have many surface problems in the processing of thin iron plates. To solve these problems, a magnetically levitated suspension is proposed and demonstrated with a simplified model apparatus which consists of an iron plate levitated by two electromagnets. >

57Fe Mössbauer spectroscopic study on surface products of thin iron plates exposed to ambient atmosphere as a means of environmental monitoring

Conversion electron and transmission Mössbauer spectroscopy were applied to the analysis of thin iron plates exposed to the ambient atmosphere. The degree of corrosion of the iron plates was classified into three categories according to the kind and thickness of rust evaluated by Mössbauer spectra. The severe corrosion took place in seaside and roadside areas. The medium corrosion was observed in urban areas, and the weak corrosion occurred in suburban and mountainous areas. This fact implies that the surface products of iron plates can successfully reflect the ambient atmosphere to which the plates were exposed.

Magnetic Field Distribution of Shadow Mask having a Magnetic Circuit around a Frame Periphery and its Affection to the Electron Beam Trajectory

The shadow mask in a color CRT is a soft thin iron plate which regulates the electron beam path. The mask may be magnetized by ambient magnetic fields, and the magnetization may change the beam path. As a result of the mask magnetization, the CRT screen may show color changes. We introduced magnetic circuits on the periphery of a shadow mask frame in order to decrease the mask and frame magnetization. The magnetic field distribution around the shadow mask was measured, and the effect of the circuits was evaluated through calculations of the change in electron trajectory. The addition of a magnetic circuit may be effective for decreasing the color change in CRT screens.

Different finite element formulations of 3D magnetostatic fields

Several finite-element formulations of three-dimensional magnetostatic fields are reviewed. Both nodal and edge elements are considered. The aim is to suggest remedies to some shortcomings of widely used methods. Various formulations are compared based on results for Problem No. 13 of the TEAM Workshops, a nonlinear magnetostatic problem involving thin iron plates.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Line element for efficient computation of the magnetic field created by thin iron plates

The problem of computing the magnetic anomaly created by iron ships in the Earth's field is considered. From a modeling point of view, one of the major characteristics of this problem is the external and uniform magnetic source (the Earth's field). A good way of taking this into account is to simulate infinity and to use the reduced scalar potential as the state function. The major difficulty in modeling ships is the presence of sophisticated 3-D geometries due to the disproportion between the global size of a ship and the thickness of the iron plates. The modeling of the thin iron plates is examined, and it is shown that an efficient method is to use line elements in 2-D and surface elements in 3-D. The authors present the finite-element formulations used, applied to scalar potentials (reduced or total). The formulations using line elements have been successfully applied, even to a magnetic region with small permeability values. Results in 2-D and comparisons with analytical solutions and actual measurements are presented. >

Fem af Bahrains hundrede tusinde gravhøje

Fem af Bahrains hundrede tusinde gravhøje

Observations of Maximum and Minimum Sea-Temperatures by Continuous Immersion

WHEN the Scotch Meteorological Society was instituted, now nearly twenty years ago, observations on sea-temperature were set on foot at the suggestion of the late Prof. Fleming, and have since been continued. These observations were made by the immersion of thermometers with small cisterns attached, and were taken at the surface and at a depth of 6 feet. Besides these, special observations were made for me on the temperature of the flood and ebb tide at depths extending to 50 feet in the Pentland Frith,* and hourly observations continued at intervals during four years ending in 1863 by Capt. Thomas, R.N., at depths extending to 60 feet.† Such occasional observations seemed to me to be insufficient to show properly the changes in temperature to which the sea is subject, and in August 1872 I suggested to my friend, Prof. Wyville Thomson, the propriety of ascertaining, on his exploring voyage, maximum and minimum temperatures by means of thermometers constantly immersed in the sea. For this purpose a thin malleable iron plate of an oval shape, as shown in Fig. 1, is fixed to the outside skin of the ship so as to form a small cell into which the sea-water finds ready ingress through numerous perforations. This cell, which need not project more than two inches, so as not to cause any appreciable obstruction to the speed of the vessel, should extend so far under the smooth water level as to prevent its lower end from rising above the trough of the sea, or an upright pipe might be placed within the vessel. In sailing ships there might be a cell on each side so as to secure constant immersion while the ship “is on a wind.” In this cell a frame carrying a maximum and minimum thermometer slides in checks so as to be capable of being raised above water to the level of the cabin or the deck, where there should be a porthole to admit of the instruments being read and the indices being readjusted.