Thin Conductive Wire Research Articles

Performance evaluation of cryogenic treated and untreated brass electrode in wire-EDM

ABSTRACT WEDM is regarded as a specialized thermo electric cutting process for precise machining in a wide range of materials with varied hardness and complex geometries that curtails utilization of conventional machining methods. The technology of WEDM process requires electricity to penetrate through a material with a thin conductive wire electrode as the tool. In this study, an untreated and deep cryogenic treated (196°C) brass wires are used to experiment with different machining variables such as peak current (IP), tension in the wire, pulse on time (TON), servo feed rate (SF), and pulse off time (TOFF). Monel 400 alloy, a work material that has high mechanical strength and corrosion-resistant properties, for which the output responses such as Surface Roughness (SR) and Material Removal Rate (MRR) are investigated. Taguchi L27 orthogonal array was selected to formulate the design of experiments and to inquire the response of each variable from the output responses. The most influencing parameters such as pulse-on time on MRR, pulse-off time as contributing parameter in surface roughness and wire tension playing a vital role in kerf width were determined by the analysis of variance. MRR is greater with untreated brass wire than cryogenic treated brass wire. Cryogenically treated brass wire provides leverage over untreated brass wire in Surface Roughness and Kerf width. Surface morphological study proves that workpiece machined by deep cryogenic treated wire electrode provides better surface finish over untreated wire electrode which has large pores, voids, and unevenly distributed re-solidified particles. Experimental results are provided to verify this approach, and conclusion is to be drawn on the wire electrode with most phenomenal aspects.

Magnetohydrodynamic levitation for high-performance flexible pumps

We use magnetohydrodynamic levitation as a means to create a soft, elastomeric, solenoid-driven pump (ESP). We present a theoretical framework and fabrication of a pump designed to address the unique challenges of soft robotics, maintaining pumping performance under deformation. Using a permanent magnet as a piston and ferrofluid as a liquid seal, we model and construct a deformable displacement pump. The magnet is driven back and forth along the length of a flexible core tube by a series of solenoids made of thin conductive wire. The magnet piston is kept concentric within the tube by Maxwell stresses within the ferrofluid and magnetohydrodynamic levitation, as viscous lift pressure is created due to its forward velocity. The centering of the magnet reduces shear stresses during pumping and improves efficiency. We provide a predictive model and capture the transient nonlinear dynamics of the magnet during operation, leading to a parametric performance curve characterizing the ESP, enabling goal-driven design. In our experimental validation, we report a shut-off pressure of 2 to 8 kPa and run-out flow rate of 50 to 320 mL⋅min-1, while subject to deformation of its own length scale, drawing a total of 0.17 W. This performance leads to the highest reported duty point (i.e., pressure and flow rate provided under load) for a pump that operates under deformation of its own length scale. We then integrate the pump into an elastomeric chassis and squeeze it through a tortuous pathway while providing continuous fluid pressure and flow rate; the vehicle then emerges at the other end and propels itself swimming.

On anomalous absorption of electromagnetic radiationby a subwave metal wire

Background: The effect of anomalously strong absorption, scattering and attenuation of microwave electromagnetic radiation by thin conductive wires is considered. The investigated effect can be used in the development of radio-absorbing and radio-masking materials for various purposes. The aim of the work is to clarify the physical nature of the effect. Materials and methods:. On the basis of the generalized Lorentz-Mi theory the mathematical model of diffraction interaction of microwave radiation with a cylindrical object which material is characterized by a complex refractive index is constructed. The case of normal incidence of a plane electromagnetic wave of E- and H-polarizations on a cylinder is considered. Numerical calculations of the field distribution were performed in the MathCard environment. Results: It is shown that for thick cylinders with a diameter greater than the wavelength, characteristic resonant peaks of absorption and scattering of wave energy are observed. For very thin cylinders, the diameter of which is much smaller than the wavelength, there are maxima of absorption and scattering of energy of incident radiation, which cannot be explained by resonant phenomena. Simplified analytical expressions for the efficiency coefficients of attenuation, absorption and scattering of electromagnetic radiation by thin cylinders are obtained. The field distributions inside and outside the dielectric and metal cylinders at different ratios of their diameter and wavelength of incident radiation are calculated. The efficiency of radiation absorption by a thin wire at different ratios of its diameter and skin-layer thickness for wire material has been studied. Conclusion: It was found that the effect of abnormally strong absorption of microwave radiation by very thin metal wires is due to the existence of a skin effect for conductive materials that interact with microwave radiation. It is obtained that the maximum efficiency of radiation absorption is achieved when the diameter of the wire is twice less than the thickness of the skin layer. The observed effect of anomalous absorption is nonresonant.

Facile Synthetic Route to Atomically Thin Conductive Wires from Single-Species Molecules in One-Dimensionally Confined Space: Doped Conjugated Polymers inside Single-Walled Carbon Nanotubes.

A facile synthetic method for doped conjugated molecules by a heating process is demonstrated. Br-terminated terthiophene precursors are encapsulated in single-walled carbon nanotubes by a vapor-phase reaction, and additional heat treatment promotes the thermal condensation of the precursors. Transmission electron microscopy observations and optical measurements show the successful synthesis of sexithiophenes and their doping (oxidation) by Br dopants generated by the condensation reaction. This study provides a new strategy for the synthesis of the doped conjugated polymers from single-species molecules by only a heating process.

A Novel Flexible PCB Conductive Structure for Electrodynamic Bearings and Measurement in its Induced Voltage

This paper proposes the concept of FlexPCB(flexible Printed Circuit Board) conductive structure for electrodynamic bearings. It has three main advantages: easy printing of considerably thin conductive wires, resulting in potential reduction in stray eddy currents; realization of specific conductive configurations with high precision to optimize the eddy current flowing; simplicity in being wound to cylinders or hollow cylinders of different diameters. To verify this new concept, the FlexPCB conductive structure was manufactured, an axial electrodynamic bearing test rig was built and the conductive structure's induced voltage was measured along the axial displacements from 0mm to 56mm at three rotating speeds. The finite element method was used to calcuatlate the flux density of electrodynamic bearing and induced voltage of the FlexPCB conductive structure. The experimental results are compared with the results from the FEM calculation. It is concluded that the measured and calculated induced voltages have consistency in the middle part of the bearing.

Non Cooperative Radar Target Identification Using Exponential Single-Mode Extraction Pulse

We present a new contribution to the single-mode extraction pulse (S-pulse) technique. The S-pulse technique uses the natural frequencies of the target as discrimination features in such a way that the field scattered by a target after it passes through a S-pulse designed for this specific target has the form of a damped sinusoid. The S-pulses are usually constructed as a linear combination of cosine or polynomial basis functions, expressing a S-pulse function as a linear combination of these functions and fixing the linear parameters with conditions on the Laplace transform. The S-pulses are synthesized using complex exponential basis functions within which are extra parameters that can be used to tune their discrimination capabilities. The proposed S-pulses are compared with the ones in the literature using thin conductive wires as simulation targets and in this way we show that there is a distinct improvement in their discriminatory capacity.

Wire-in-a-Nozzle as a New Droplet-on-Demand Electrogenerator

Many engineering applications assume the generation of single spherical droplets on demand. Piezo and thermo droplet-on-demand (DOD) instruments are not able to produce droplets with a broad range of size distributions from the same nozzle. We show that this challenge can be resolved using the principles of electrostatic generation and capillarity. A thin conductive wire threaded through a needle can be used as the droplet electrogenerator (or DOD generator). By applying a weak-bias electric field, one can deliver a drop from the needle edge to the free wire tip. When the drop moves toward the wire tip, it leaves behind a thin coating film. The capillary pressure of this cylindrical film helps isolate the droplet from the liquid source: the film spontaneously thins, breaking the connection between the droplet and the liquid source. The detachment of a pendant drop from the wire is then achieved by applying a short voltage pulse. Using the wire-in-a-needle nozzle, we were able to produce single droplets ranging from 50 to 500 μm, and we were able to deposit them with controlled velocity in a prescribed position. Therefore, the proposed method offers new opportunities in fields dealing with the DOD applications.

Matching a Bluetooth headset antenna on a small system ground by using a conductive wire

AbstractIn this article, a simple, yet effective method for matching a compact planar inverted‐F antenna (PIFA) on a small system circuit board for Bluetooth headset applications is presented. The antenna is perpendicular to and extends along the top and right sides of the system ground, making it possible for the antenna to occupy almost no limited board space. Results have shown that by introducing a thin conductive wire soldered to the bottom corner of the system ground, good input matching over the 2400–2484 MHz band can easily be achieved for the PIFA mounted on a small ground of length less than a quarter wavelength at 2440 MHz. Radiation measurements of the proposed design in a real headset attached to a standard head phantom are also taken. Details of the obtained experimental and simulation results are given and discussed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2802–2805, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24755

Formation of complex features using electron-beam direct-write decomposition of palladium acetate

A focused electron beam has been used to selectively decompose thin films of palladium acetate, (Pd–Ac), resulting in the formation of ≤50 nm wide conductive Pd-rich features. The formation of features from various film thicknesses of Pd–Ac has been investigated using a wide range of electron energies. Monte Carlo simulations of electron energy loss distributions in Pd–Ac films were calculated over a wide range of film thicknesses and electron energies. The Monte Carlo calculations were used to predict the volume over which the energy of the electron beam is deposited within the films. Thin conductive wires having profiles from high aspect ratio to almost circular cross sections produced by varying the electron beam energy were in agreement with the Monte Carlo predictions. Complex multilayer Pd–Ac features were then fabricated by performing overlapping exposures of Pd–Ac films with differing electron beam energies.

Irregular field-shaping for 60Co teletherapy.

With the revival of interest in en bloc, large-field, supervoltage template or “mantle” radiotherapy, especially in the treatment of Hodgkin's disease and the malignant lymphomas (6), there have arisen a concern and a need for idealized and individualized treatment-planning, utilizing accurately reproducible irregular field-shaping devices. Most shielding systems described in the literature, whether vertical or horizontal, employ separate lead or lead-equivalent blocks cut or poured into the desired contour and placed upon a stationary or movable fixation device or platform in order to shield critical or non-tumor-bearing areas (1–4). Such systems are generally time-consuming and relatively crude, and many suffer from the basic defect of not insuring day-to-day reproducibility of grossly irregular fields. During the past year we have developed at the Radiotherapy Center of the University of Wisconsin Hospitals a modified method of irregular field-shaping for cobalt teletherapy. The technic, based upon one described by Thomas (7), is characterized by great flexibility, relative low cost, and ease of day-today reproducibility. Description of Method A diagnostic roentgenogram of the proposed treatment area (Fig. 1, a) is exposed at the desired source-skin treatment distance (SSD). The central axis of the diagnostic beam is indicated on the entrance surface of the patient and thus on the film also by a crossed copper wire of appropriate thickness. The target (source)-film distance is then recorded. The desired areas to be shielded, i.e., lung parenchyma, larynx, etc., are then indicated by the radiotherapist on the processed roentgenograms. From this prepared roentgenogram the central ray crossing and areas to be shielded are transferred, preserving scale, onto white onion-skin paper. This “template” is then positioned (Fig. 1, b), centered below a point equivalent to the target of the diagnostic x-ray tube at the previously determined target (source)-film distance. A Styrofoam block measuring usually 3 X 12 X 12 inches is centered with the undersurface at a predetermined and fixed distance over the treatment area as indicated on the template. We have arbitrarily selected 78 cm for our cases. A thin conductive wire is extended from a point corresponding to the focus (or source) through a hole drilled in the Styrofoam (previously determined to lie within the area to be shielded) and extended to a stylus which just touches the prepared template. When the wire is heated by applying a 10-volt A.C. between points A and B, it cuts through the Styrofoam block in a pattern duplicating in reduced scale the contour of the irregular field-shaping indicated on the roentgenogram and transferred to the template. This is done for each discontinuous area of the template which is to be shielded.

Technique of Measuring Gas Stream Velocity by means of Electric Discharge

A new measuring technique of gas stream velocity, based on the phenomena that the path of electric discharge moves downstream under influence of gas stream, has been developed. A probe, a thin conductive wire grounded by a resistor, is placed at a distance l downstream from electrodes. When the discharge path arrives at the probe, the probe voltage rises rapidly. By means of measuring the time interval τ, elapsing between the beginning of spark and the rising of probe voltage, the stream velocity w can be determined by the formula, w=kl/τ, where k is a constant, independent of distance l, intensity of turbulence, temperature and pressure of flowing gases. The value of k depends only on electrode spacing. Digital measurement of τ can be made easily. This technique can be applied to not only steady but pulsating flow such as suction flow of internal combustion engines.