Thin Metal Strips Research Articles

Composite manufacturing of metal porous thin strip with metal wire mesh and powder

Porous metal materials are applied in various industries, among which powder rolling is the most widely used process for preparing porous metal materials. Then, metal porous materials prepared solely from powder as raw materials have the disadvantage of low mechanical properties, while wire mesh as reinforcement can effectively improve tensile strength. The preparation process of wire mesh powder composite is complex and requires the addition of adhesives. In this article, the mechanical properties of thin metal strips prepared by powder and wire mesh composite vertical rolling were much higher than those prepared by pure powder. Moreover, this thin strip had porous characteristics, and the preparation process was simple and easy to promote. This research could provide a reference for the powder metallurgy field, especially for the preparation of metal porous materials by vertical rolling.

Uniplanar printed four‐port MIMO antenna with self‐coupling‐self‐decoupling mechanism

SummaryThe proposed research is primarily investigated with a new methodology of utilizing parasitic constrictors (PCs) as self‐coupling‐self‐decoupling (SCSD) mechanism which has been strategically implemented in multiple‐input multiple‐output (MIMO) antenna design. The design asserts an uniplanar printed four‐port MIMO antenna configuration in a confined footprint of 0.6 0.6 0.015 ( = lowest operating wavelength at 2.9 GHz), where the radiator and reflector act as an effective SCSD invoking spatial diversity. The orthogonally oriented radiators are composed of 4 circular disc with a 45° tilt and cutaway for reducing near‐field condensed currents and improve 10‐dB impedance matching. The antennas are assisted with a uniquely designed coplanar wave guides as SCSD, with rotationally symmetric PC. The PC has coplanar slots and a thin metallic strip that connects to a center‐fed annular disc as intrinsic current neturalizer. A pair of inverted L‐shaped symmetric strips is introduced in the coplanar slots to effectively couple the near‐field currents for self‐induced resonance mechanism as well as self‐decoupled for isolation improvement. To validate the rational counterparts, a prototype antenna has been simulated, fabricated, and experimented to operate from (2.9–5.45) GHz. The potential outcomes show good convergence in simulated and experimental results, with effective 10‐dB IBW, isolation, and diversity parameters, and demonstrate its prospective in C‐band (5G) applications.

Metal threads in Qing Dynasty Chinese ‘silk and metal carpets’

Chinese ‘silk and metal carpets,’ mainly made by imperial workshops during the Qing Dynasty (1644–1911), are very luxurious and until now have not scientifically and technically been investigated. From the point of view of materials, a typical feature is the presence of metal threads which embellish backgrounds or details with a precious and golden appearance. Metal threads from a wide number of Chinese carpets were non-destructively investigated by XRF, while an in-depth characterization by SEM-EDS was performed on samples from few carpets.Although copper is always the main constituent of very thin metallic strips wound around a core of silk, the obtained results showed three types of strips, different in terms of materials and/or methods of making. The most frequent typology, covering over 85% of the investigated carpets, derives from the drawing of brass-plated copper wires.The obtained results are read and interpreted according to geographical and historical context, pertaining to the metallurgy and the making of metal threads, extending the comparisons also to other contexts in eastern and western world, during the ages.

Unexpected flange crippling of a newly built cyclist bridge

AbstractEncouragement of cycling is an effective way to reduce energy consumption by traffic. Cycling lanes will, to the greatest extent practicable, be built close to currently used traffic roads in order to establish new, swift lanes that require little space. Building near railroads appears acceptable for the latter, preferably by cantilevered structures atop existing bridges. In the event that this is not acceptable, separate bicycle bridges may be constructed next to the railroad bridges. On the Brussels Ring Highway, close to the Zaventem Airport, the latter was the situation. The oblique bearing points at the extremities of the straight‐ended sections, used to construct this bicycle bridge experienced torsional moments during installation. This resulted in distinct folds in the bottom flange of the closed cross‐section of one of the six bridge decks. Both global FE‐models and more detailed models were created to explain this. None could adequately account for the observed flange crippling. The crippling can only be explained by an unintentionally increased torsion, which may have occurred during the manipulation of the bridge's component elements. Additional thin metal strips have been added to this section of the bicycle bridge to restore its bearing capacity.

Shear horizontal wave propagation on a piezoelectric semiconductor substrate under slight ridge or thin metal strip gratings

In the present work, analytical solutions for shear horizontal (SH) waves propagating in an n-type piezoelectric semiconductor (PSC) substrate under periodic slight ridge or thin metal strip gratings are obtained. The solutions of the various physical fields can be expressed as a summation of infinite harmonic waves by using the Bloch–Floquet theorem due to the existence of the periodic ridge or metal grating. Based on the numerical calculations, the effects of the width, height and shape of the ridge, the doping density of the PSC substrate and the material properties of the metal grating on the dispersion and attenuation curves of the SH waves are investigated. The results show that both the periodic ridge and metal grating have evident effects on the propagation characteristics and displacement mode shapes of the SH waves and the effects are closely related with the ratio of the wavelength to the structure period. In addition, the metal gratings can better control the propagation characteristics of SH waves than the ridges, namely, the effects of the metal gratings are more obvious and flexible than that of the ridges.

Design and Analysis of Microstrip Patch Antennas for Narrow Band Communication Applications

Abstract- Microstrip antennas are low-profile antennas. A metal patch mounted at a ground level with a dielectric material in between constitutes a Microstrip or Patch Antenna. These are very low- size antennas having low radiation. The patch antennas are popular for low-profile applications at frequencies above 100 MHz, these antennas consist of a very thin metallic strip placed on a ground plane with a dielectric material in-between. Usually, the antennas are chosen to be circular or rectangular in shape for ease of analysis and fabrication. These antennas are employed at ultra-high frequencies and higher frequencies. This paper aims to design and analysis of microstrip patch antennas for Narrowband Communication Applications by the analysis on antenna parameters such as Voltage Standing Wave Ratio (VSWR), S11 Parameters, Radiation Pattern and Gain. Dielectric materials FR4 Epoxy, RT Duroid 5880, RT Duroid 6006 and RT Duroid 6010 are considered whose permittivity is 4.4, 2.2, 6.15 and 10.2. The antennas are simulated at 900 MHz frequency using Ansys Electromagnetic Suite (HFSS) software and the resultant graphical analyses of the parameters are plotted. The antennas are also fabricated with the above dielectric materials and are tested for practical values using a network analyser using Midas software. The results show that RT-Duriod 6006 gives better values when compared to the other substrate materials. The gain observed is 12.6 dB with a VSWR of 1.65. From the obtained results, it can be concluded that the antenna made from this substrate material (RT-Duriod 6006) are best suited for narrow band communication applications.

Broadband tunable mid-infrared absorber based on conductive strip-like meta-atom elements

A metamaterial composed of thin metallic strips as an efficient broadband absorber in the mid- infrared spectrum is investigated. Here the matching between dielectric and geometrical properties of the individual elements is critical to ensure high absorption. Detailed theoretical analysis based on the electric dipole approximation is performed to characterize the absorption and scattering properties of the individual elements of the unit cell and the results are used to design the metamaterial composed of such configurations. The absorption cross-section of a strip-shaped element can exceed its longitudinal geometrical cross-section area by 17 times. It was shown that the absorptance of the Ni-based metal-insulator-metal (MIM) metamaterial structure can exceed 90% in ~8.2 – 18 µm spectrum. The broadband absorption is associated with the excitation of the low-Q-factor dipole modes of the strips. Such an absorber demonstrates good polarization and incident angle tolerance for transverse-electric (TE) waves. The absorption spectrum can be tuned by varying individual element parameters.

Automated system for design and calculation of heating devices for hot die forging

Methods of mathematical modeling, basic technologies and methods of modeling in various design systems of the stamping process are considered. The canonical equations of temperature stresses are obtained, which make it possible to obtain a picture of the temperature distribution over the workpiece area during heating. A mathematical model has been developed for a thin metal strip during heating; thermal stresses arising in it due to uneven heating have been described. Numerical modeling has been carried out on the basisof field data, which will allow verification of the automated environment for the selection of functional and design schemes and the calculation of the parameters of heating devices in hot volumetric stamping of workpieces in terms of speed, energy efficiency, heating quality: accuracy of achieving specified temperatures and maximum heating uniformity. By areas, ease of use and readjustment, resource, reliability and maintainability. The proposed system will include the following CAD elements: databases and rules for operating with them, calculation modules, modules for selecting and matching options.

Isolation enhanced compact dual-band quad-element MIMO antenna with simple parasitic decoupling elements

In this work, a simple parasitic decoupling structure integrated compact dual-band quad-element Multiple-Input Multiple-Output (MIMO) configuration with improved isolation is proposed for 3.5 and 5.8 GHz bands of Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Local Area Network (WLAN) applications. The lower and higher frequency bands accomplish an impedance bandwidth of 400 MHz (3.35 – 3.75 GHz) and 450 MHz (5.6 – 6.05 GHz), respectively. A slot integrated curve-shaped compact (11 × 20 mm2) dual-band monopole antenna is explored to implement the proposed compact MIMO configuration. A parasitic decoupling structure comprising T and inverted L-shaped thin metal strips is introduced between the orthogonally placed antenna elements. It exhibits dual stopband characteristics to enhance the isolation significantly at the targeted frequency bands despite the compact footprint (34 × 34 mm2) of the MIMO geometry.The optimized decoupling structure improves the isolation between the elements by 31.5 and 32 dB in the lower and higher bands than the MIMO geometry without decoupling elements. The antenna provides good radiation characteristics with peak gains of 4.18 and 3.62 dBi within the bands. The computed diversity metrics, such as envelope correlation coefficient (< 0.01), diversity gain (> 9.93 dB), mean effective gain ratio (-0.13 to 0.16 dB), channel capacity loss (< 0.4 b/s/Hz), and total active reflection coefficient (< -10 dB), ensures good diversity performance. The fair agreement between the simulated results using HFSS EM solver and the measured results on the fabricated prototype validated the proposed MIMO configuration.

Stray-Capacitance As a Simple Tool for Monitoring and Locating Heat Generation Demonstrated in Three Superconducting Magnets

Real-time monitoring of heat loads in cryogenic systems is critical for many applications, particularly high field magnets. We demonstrated that by monitoring changes in the capacitance of local probes consisting of thin metal strips with a porous glass fiber dielectric, boiling helium from as little as 0.1 J of deposited heat can be located by an analysis of the response speed and amplitude in nearby probes. We further implemented stray-capacitance monitoring of a magnet's metal support structures, a more global probe of the magnet volumes, in three high temperature superconducting Bi-2212 magnet types. Global structural stray-capacitance monitoring was evaluated for a single racetrack coil, a common coil dipole, and a canted cosine theta winding, showing a quench response comparable to voltage signals without inductive effects. The response of the local and global probes was compared in the single racetrack coil with well-known quench properties. Monitoring the cool-down of the common coil dipole demonstrated the added benefit of the global stray-capacitance as a liquid level monitor. This simple method of monitoring the capacitance has proven to be a versatile and robust technique for monitoring and locating heat.

Enhancement of polarization purity in square dielectric resonator antenna using coaxial feed with metal strip loading for point-to-point communication applications

In this paper, a simple technique to enhance the polarization purity in a square dielectric resonator antenna (SDRA) using metal strip loading on the probe feed is presented for point-to-point communication applications. Coaxial feed placed at the commonly used offset location adjacent to the DRA has been studied in this regard. Cross polarized (XP) fields scattered from the feed into the air are found to be one of the reasons behind the deterioration of polarization purity in SDRA. When a thin metal strip is loaded on the probe feed using liquid solder to control these XP fields, the measured result shows an XP isolation of 47 dB at the boresight, 42 dB and 29 dB at the angular region of ±30°in the E-plane and H-plane, respectively. The proposed technique helps to overcome many unavoidable fabrication errors associated with complex machining and drilling processes involved in contemporary DRA designs for XP suppression. The proposed SDRA design offering good XP isolation performance and simple fabrication technique is highly suitable for low cost and high precision applications.

Switchable Micro-Strip Pin Diode Patch Antenna With Slot Changing Method for Wide Band Frequency Applications

A novel microstrip rectangular patch antenna adopting a quarter-wave transformer feed with switchable resonant frequency capability. Switchable (Reconfigurable) antennas symbolize innovation in antenna design that transforms the classical fixed-form, fixed-function antennas to modifiable (Changeable) structures that can be adapted to the provisions of a time-varying system. Advances in microwave semiconductor processing technologies have thereby enabled the use of compact, ultrahigh quality RF and microwave switches in innovative aspects of antenna design. The creation of dynamic radiating structures that can be reconfigured during the operation is new tools that were made possible to design through the High quality, miniature RF switches (e.g. PIN Diode) provided to the antenna designer. The proposed antenna design is obtained by using a C shaped slot cut on the reference patch that is linked by a thin metallic strip incorporating one PIN diodes to obtain the dual-frequency transection. By dominant the PIN diode prejudice voltage potential (-9 Volts for reverse bias & +9 Volts for forwarding bias), the aerial possibly interchanged separating two dissimilar frequencies. It is indicated through the Simulation results that without any additional matching elements, the proposed. Antenna demonstrates an extremely excellent input coincide designed two resonant frequencies of 3.66GHz and 6.5 GHz. These two resonant frequencies depend on the operation of the diode.

Transparent capacitive micromachined ultrasonic transducer (CMUT) arrays for real-time photoacoustic applications.

Photoacoustic imaging has shown great potential for non-invasive high-resolution deep-tissue imaging. Minimizing the optical and acoustic paths for excitation and detection could significantly increase the signal-to-noise ratio. This could be accomplished by transparent transducers permitting through-transducer illumination. However, most ultrasound transducers are not optically transparent. Capacitive micromachined ultrasound transducer (CMUT) technology has compelling properties compared to piezoelectric transducers such as wide bandwidth and high receive sensitivity. Here, we introduce transparent CMUT linear arrays with high transparency in the visible and near-infrared range. To fabricate the devices, we used an adhesive wafer bonding technique using photosensitive benzocyclobutene (BCB) as both a structural and adhesive layer with a glass-indium-tin-oxide (ITO) substrate. Silicon nitride is used as the membrane material ensuring hermiticity and optical transparency. Our fabricated transducer arrays consist of 64 and 128 elements with immersion operation frequency of 8 MHz, enabling high-resolution imaging. ITO, along with thin metal strips, are used as a conductive layer for the top electrodes with minimal impact on device transparency. Fabricated devices have shown average transparency of 70% in the visible wavelength range that goes up to 90% in the near-infrared range. Arrays are wire-bonded to interfacing electronics and connected to a research ultrasound platform for phantom imaging. Arrays exhibited signal-to-noise (SNR) of 40 dB with 30V bias voltage and laser fluence of 13.5 mJ/cm2. Arrays with 128 channels provided lateral and axial resolutions of 234 µm and 220 µm, respectively.

A feasibility study of continuous grain refinement of sheet metal

Various severe plastic deformation (SPD) techniques have been used to develop ultrafine-grained (UFG) materials to enhance material properties. Equal channel angular extrusion/pressing (ECAE/ECAP) is an effective technique to severely deform material and refine grains, however, the drawback is that a continuous process on sheet metal is confined due to the process mechanism. Equal channel angular drawing (ECAD), a continuous strip drawing process, has limitations in achieving grain refinement because drawing is a stretching phenomenon contrary to an extrusion or pressing process. In the present work, experiments were conducted on interstitial-free (IF) steel to demonstrate that grain refinement of thin sheets can be achieved through pack extrusion; and while there was shear deformation, ECAD failed to produce UFG microstructure. The finite element analysis showed the sheet metals have distinctive stress-strain states after ECAE and ECAD. The feasibility of combining ECAE and ECAD to approach the stress-strain state of the sheet metal in pack extrusion for grain refinement was investigated. Simulation results showed that with proper loading conditions, continuous grain refinement of thin metal strips is sufficiently possible.

Temperature Control for Induction Heating of Thin Strips

In this work, a model-based temperature controller for an induction heating system for moving thin metal strips is developed. The most significant disturbance of the system is an uncertain air gap geometry caused by flatness defects of the metal strip. A computationally expensive calculation of the electromagnetic field is avoided by using an equivalent circuit model and the energy balance. A thermal model of the moving strip is derived in the form of a convection-reaction equation and simplified to a linear time-invariant model. A 2-degrees-of-freedom controller is designed based on the simplified model and tested using a finite-element simulation model of the induction heating system. The simulations demonstrate that the proposed controller clearly outperforms standard feedback control strategies.

Dual-Polarized Multi-Resonance Antennas With Broad Bandwidths and Compact Sizes for Base Station Applications

In this paper, a novel design method for dual-polarized multi-resonance antennas is presented for base station applications. The radiator of the antenna is configured as cross-dipoles with four thin metal strips connected to the adjacent dipole arms. The attached strips create multiple current paths and introduce additional resonant points. As a result, the bandwidth of the antennas is broadened while maintaining a very compact size. Based on this working mechanism, two multi-resonance antennas are designed, fabricated, and tested. The antennas achieve bandwidths of 46.7% and 66.7% respectively, with excellent matching capabilities. The antennas also exhibit high port isolation levels and stable radiation performances. The promising wideband performances with compact physical sizes make the antennas highly suitable for the base station applications.

Hierarchical shape optimization of one-sided transverse flux heating induction coil

Purpose The transverse flux heating (TFH) concept offers very high electrical efficiency in combination with unique technological flexibility. Numerous advantages make this method beyond competition to be applied in e.g. processing lines. However, all potential advantages of TFH can be realized in practice only by optimal design of the inductor shape using numerical modelling and optimization techniques. This paper aims to describe a hierarchical approach to the optimal design of a one-sided induction coil, which will be used for one-sided TFH of continuous moving thin metal strip to achieve a homogeneous temperature distribution along the strip width. Design/methodology/approach Depending on the design step, 2D or 3D FEM simulations using ANSYS® Mechanical including the electromagnetics package are used. The harmonic electromagnetic solution is coupled to a transient thermal model which takes the strip movement into account. All models use the symmetries of the inductor workpiece arrangement to keep the calculation times as low as possible. Findings Due to the geometry of a TFH coil, the models can image a quarter or half of the arrangement. Preliminary investigations of different inductor head shapes can be carried out quickly and then further improved on more complex models in combination with the use of optimization algorithms. Practical implications Using hierarchical structure for designing a one-sided TFH coil, offers an efficient and quick way to create a coil which is adapted to the application. Originality/value The one-sided inductor design is considered, and the results are generally valid.

Shear horizontal wave propagation along a periodic metal grating surface of a magneto-electro-elastic substrate

This paper analyzes shear horizontal (SH) waves propagating in thin metal strips deposited periodically onto the surface of a magneto-electro-elastic (MEE) substrate. The MEE substrate is assumed to be a transversely isotropic crystal with 6 mm symmetry or a hexagonal (6 mm) crystal. A field analysis method, which is based on the Bloch–Floquet theory and the coupled equations of wave motion, is employed to derive the dispersion equations and wave mode shapes. Numerical examples are presented for an MEE composite (PZT4/CoFe2O4) and an aluminum (Al) strip. For comparison, different constituent ratios of PZT4/CoFe2O4 are considered. The effect of the ratios of strip height and width to grating periodicity on frequencies, phase velocities, as well as wave mode shapes is discussed in detail. The results show that there is a bandgap at the resonance condition when the grating periodicity matches the wavelength of the SH surface wave. This metal grating surface can trap SH surface waves by slowing the SH waves. The wave mode shapes indicate that the SH surface waves are trapped mainly on these metal strips. As the ratio of strip height to grating periodicity increases, the trapping effect is more pronounced and the gap becomes wider. The ratio of strip width to grating periodicity significantly affects the behavior of SH surface waves. The present results are relevant in the application of MEE surface acoustic wave resonators.

Electrical and Exergy Analysis of a Simple Pass Photovoltaic–Thermal (PV/T) Air Heater with Slats Under Weather Conditions of the Far Nord Region, Cameroon

In this paper, a simple pass photovoltaic-thermal air heater system with slats has been considered to study its electrical and exergy performance by theoretical and numerical analysis. The collector has been modeled in such a way that the absorber plate is totally covered by photovoltaic modules. The climatic data (solar irradiation, ambient temperature) of the Far Nord region of Cameroon have been used. Thin metallic strips called slats have been attached longitudinally at the bottom side of the absorber plate of the system. The first and second laws of thermodynamics have been applied to write the equations describing the functioning of the system. These equations have been solved by numerical computation using the gradient conjugate method. The influences of some operating parameters on the electrical and overall exergy efficiencies were investigated. It was found that (i) it is of great importance to use slats as an integral part of the absorber surface in order to achieve better efficiencies of single pass photovoltaic-thermal systems and (ii) the instantaneous overall electrical and overall exergy efficiencies of a simple pass hybrid (PV/T) solar air heater varies between 9-12% and 11,5-18,5% respectively.

Experimental study of rotating convection in the presence of bi-directional thermal gradients with localized heating

We conduct experiments on the convective dynamics of a rotating fluid in a novel configuration, which comprises of a cylindrical annulus with peripheral spot heating at the bottom on the outer edge and uniform cooling on the inner edge. This system naturally provides an additional vertical gradient on the outer edge of the annulus, along with a radial gradient, thereby mimicking the thermal gradient patterns encountered in a real atmosphere. Localized heating is carried out at the bottom using a thin annular metal strip of thickness, h=5 mm. Water is used as the working fluid. Once the system reaches a statistically steady state, localized temperature measurements are carried out at various radial locations along the vertical fluid height. We measure time series of the temperature at several locations and visualize the flow structures over a range of Taylor number Ta (spanning 6.5 × 108- 2.7 × 109) and Rayleigh number Ra (spanning 2.2 × 108- 6.2 × 108). Temperature time series data at different heights, z, near the outer edge, along with two point correlations of temperature data indicate that, in the presence of rotation, columnar convective plumes (CCP) exist above the heating zone that aid in the vertical transport of heat. Qualitative flow field and temperature measurements in the bulk fluid also indicate the existence of baroclinic waves, which aid in the horizontal transport of cold and hot fluids between the annuli. The two point temperature correlations show that these waves break into eddies as the value of Ta increases. Overall, it is speculated that heat transport in this new configuration is governed by the co-existence and interplay of convective plumes and baroclinic waves/eddies, which closely simulates the dynamics of geophysical motions. It is found that the heat transport near the outer edge and in the fluid bulk is a strong function of Ra and Ta. For the highest value of Ra=6.2 × 108, the radial heat transport was most effective at Ta=0. However, at lower values of Ra, the radial heat transport in the outer and bulk regions was highest at Ta=1.5 × 109. These results indicate that an optimum value of Ra and Ta exists at which the convection driven radial heat transport is most energetic through the interaction of CCP and baroclinic waves/eddies.