Walls Of Box Research Articles

Study on Square Conical Box NC Sheet Meta Incremental Forming

The principle of NC incremental sheet metal forming as well as the process planning, experiment of the square conical box forming are presented. Because the deformation of sheet metal only occurs around the tool head and the deformed region is subjected to stretch deformation and thins, and surface area increases. Sheet metal forming stepwise is to lead to the whole sheet metal deformation. The sine law indicates that the thickness of the square conical box wall is close to zero when the half-apex angle of the square conical box wall is close to zero. Therefore, we must know the forming limit half-apex angle to ensure that the forming can be carried out successfully, i.e., to ensure that the deformed region with a certain thickness will not fracture. It will succeed in square conical box incremental forming in a single tool-path if the forming is carried out with an angle which is larger than the forming limit half-apex angle. The fracture in the forming component can be avoided by these methods. A square conical box of uniform wall-thickness can be formed by NC incremental forming process. The thickness of deformation area is increased by increasing half-apex angle. The wrinkle in the forming component can be avoided by these methods.

The optimisation of the energy absorption of partially Al foam-filled commercial 1050H14 and 6061T4 Al crash boxes

Partially Alulight and Hydro Al closed-cell foam-filled commercial 1050H14 Al and 6061T4 Al crash boxes were optimised using the response surface methodology in order to maximise specific energy absorption (SEA). The quasi-static crushing of empty and filled crash boxes was simulated using LS-DYNA, and the results were further confirmed with experimental quasi-static crushing testing of empty and Alulight foam-filled commercial 1050H14 Al crash boxes. Results showed that partial foam filling of commercial crash boxes increased both SEA and mean load because of foam filler axial and lateral deformation in between the progressing folds of the crash box. Within the studied constraint range of box mean load, box wall thickness and foam filler density, the optimised Alulight and Hydro foam-filled 1050H14 and 6061T4 crash boxes resulted in 26%–40% increase in total energy absorption as compared with empty crash boxes. Considering the same weight basis, the use of a higher yield strength box wall material and higher plateau stresses of Al foam filler resulted in higher energy absorptions in partial foam-filled boxes at relatively low displacements.

Application of the particle in a box electronic circuit in a spread spectrum communication system

A spread spectrum communication system based on the electronic model of the particle in a box system is proposed. This electronic system allows a robust and simple electronic emulation of the mechanical behaviour of the collisions of a particle inside a box, exhibiting rich chaotic behaviour. The required non-linearity to emulate the box walls is implemented in a simple way when compared with other analogue electronic chaotic circuits. In this system, a stream of binary data is transformed in the frequency modulated signal by the binary frequency shift keying (BFSK) modulator. The chaotic signal of the particle in a box electronic circuit is used to generate a broadband signal in the voltage controlled oscillator (VCO) of the transmitter. The frequency hopping signal sent to receiver is generated by mixing the binary frequency shift keying and the broadband signal. The demodulation process is done when the VCOs of transmitter and receiver are synchronised by a phase locked loop (PLL) circuit. The performance of the demodulation process is verified through the eye pattern technique applied on the recovered bit stream. A binary data stream was sent through a transmission channel with the following lengths: 2,000 metres and 8,000 metres. The experimental results demonstrated that the particle in a box electronic circuit can be used in a spread spectrum communication system.

An optimum superconducting ultra-wideband bandpass filter at VHF band

A highly selective superconducting ultra-wideband filter with a passband from 125 to 260 MHz is designed and demonstrated using a microstrip structure. The filter is designed according to a circuit model for an optimum short-circuited stub transmission-line filter and consists of 10 shunt short-circuited stubs separated by connecting lines. The short-circuited stubs are quarter-wavelength long, and the connecting lines are half-wavelength long. The filter is realized on two 3-inch YBCO/LaAlO3 substrates, which are connected by two bonding wires. The short-circuited stubs are grounded via two grounding pads that are attached to the box wall by a number of SiAl bonding wires. The measured results exhibit a selective filtering characteristic equivalent to a 19-pole Chebyshev filter and a low insertion loss of less than 0.1 dB at center frequency without tuning. Furthermore, the experimental results of the filter are in good agreement with the simulated ones. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2639–2641, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25571

Measurements of plasma temperature in indirect drive targets from the shock wave velocity in aluminum in the Iskra-5 facility

Results are presented from the development of a method for measuring plasma temperature in indirect (X-ray) drive targets by recording the shock wave velocity in the Iskra-5 facility. The samples under investigation were irradiated by X-rays in a converter box, and the shock wave velocity was determined from the time at which the wave reached the back surface of the sample and the surface began to emit visible radiation. This emission, in turn, was detected by a streak camera. The results of experiments on the interaction of X radiation with a hot dense plasma, as well as the accompanying gas-dynamic processes in aluminum samples, are analyzed both theoretically and numerically. In experiments with Al and Pb samples, the shock wave velocity was measured to vary in the range U = 8–35 km/s, and the range of variation of the temperature of the box walls was measured to be Te = 140–170 eV.

Partial Al foam filling of commercial 1050H14 Al crash boxes: The effect of box column thickness and foam relative density on energy absorption

The crushing behavior of partially Al closed-cell foam filled commercial 1050H14 Al crash boxes was determined at quasi-static and dynamic deformation velocities. The quasi-static and dynamic crushing of the boxes were simulated using the LS-DYNA. The results showed that partial foam filling tended to change the deformation mode of empty boxes from a non-sequential to a sequential folding mode. In general, the experimental and simulation results showed similar mean load values and deformation modes. The SEA values of empty, partially and fully foam filled boxes were predicted as function of box wall thickness between 1 and 3 mm and foam filler relative density between 0 and 0.2, using the analytical equations developed for the mean crushing loads. The analysis indicated that both fully and partially foam filled boxes were energetically more efficient than empty boxes above a critical foam filler relative density. Partial foam filling, however, decreases the critical foam filler density at increasing box wall thicknesses.

Hermetic Sealing of Stainless Steel Packages by Seam Seal Welding

Welded stainless steel packages offer a number of advantages relative to those fabricated from kovar or aluminum metals and braze sealed. They are highly resistant to corrosion, especially in aqueous or elevated temperature environments, are mechanically stronger, dramatically so at temperatures above 100°C, exhibit lower outgassing rates, and have better vibration characteristics. Since welded stainless steel packages do not require over plating to facilitate braze sealing, combined material and fabrication costs are lower than kovar or aluminum packages. Also, unlike kovar, stainless steel is nonmagnetic, which is advantageous in many electronic applications. For sealing stainless steel packages, we elected to use seam sealing rather than laser welding for two reasons. Seam sealing subjects the package contents to lower thermal excursions than laser welding because less material is melted to achieve a weld in seam sealing. Second, seam sealing confines the molten material between the cover and package, where as laser welding produces a surface filet. Consequently, there is more opportunity for molten metal to splatter or react with the atmosphere in laser welding than in seam sealing. We successfully developed a process to weld a 2 millimeter thick cover onto a box with dimensions of 75 mm long by 50 mm wide by 15 mm deep using a seam sealer. The box walls were 1 mm thick and were penetrated by a dozen glass insulated feedthrus on one side. Both cover and box were fabricated from 316L stainless steel. A combination of analytical and finite element modeling were used in conjunction with a designed experiment to optimize the process variables of roller angle, speed and pressure, weld current, pulse shape, duration and spacing, number of weld passes, and sealing atmosphere. Weld quality and seal integrity were evaluated by leak testing before and after environmental stressing, mechanical testing and metallographic cross sectioning. The effects of component dimensions and tolerances on seal integrity were also investigated. Particular attention was paid to cover flatness, flange thickness, and tightness of fit between the cover and box. The process development was concluded by conducting a qualification experiment that used the optimized process parameters with controlled variation about their nominal values. A 100% yield of sealed boxes was obtained. These test articles were then subjected to various environmental screening tests, which were all passed with no failures.

Prediction of swelling pressures of expansive soils using artificial neural networks

Swelling behavior of expansive soil is a complicated phenomenon. In order to cope with the complications in describing the swelling behavior of expansive soil, researchers developed alternative approaches. In this paper, the prediction model of transmitted lateral swelling pressure, and vertical swelling pressures on a retaining structure was developed using artificial neural network (ANN) approach. In the first stage of this study, the lateral and vertical swelling pressures were measured with different thicknesses of expanded polystyrene (EPS) geofoam placed between one of the vertical walls of the steel testing box and the expansive soil. Then, artificial neural network was trained using these pressures for prediction transmitted lateral swelling pressure, and vertical swelling pressures on a retaining structure. Results obtained from this study showed that neural network-based prediction models could satisfactorily be used in obtaining the swelling pressures of the expansive soils.

A Superconducting Microstrip Ultra-Wideband (UWB) Bandpass Filter at VHF-Band

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A compact superconducting ultra-wideband filter with a passband from 125 to 260 MHz is demonstrated. The filter consists of ten shunt short-circuited stubs separated by connecting lines. The short-circuited stubs are grounded via a grounding strip that is attached to the box wall by a number of SiAl bonding wires. The filter is realized on two 2 in <formula formulatype="inline"> <tex Notation="TeX">${\rm YBCO/LaAlO}_{3}$</tex></formula> substrates, which are connected by two bonding wires. The measured results demonstrate an insertion loss of less than 0.08 dB and a return loss of better than 21 dB without tuning. Furthermore, the experimental results of the filter are in good agreement with the simulated ones. </para>

Experimental investigation of turbulent flow through spacer grids in fuel rod bundles

This paper contains experimental data of pressure, velocity and turbulence intensity in a 24-rod fuel bundle with spacer grids. Detailed pressure measurements inside the spacer grid have been obtained by use of a sliding pressure-sensing rod. Laser Doppler Velocimetry technique was used to measure the local axial velocity and its fluctuating component upstream and downstream of the spacer grid in sub-channels with different blockage ratios. The measurements show a changing pattern in function of radial position in the cross-section of the fuel bundle. For sub-channels close to the box wall, the turbulence intensity suddenly increases just downstream of the spacer and then gradually decays. In inner sub-channels, however, the turbulence intensity downstream of the spacer decreases below its upstream value and then gradually increases until it reaches the maximum value at approximately two spacer heights. The present study reveals that spacer effects, such as local pressure distribution and turbulence intensity enhancement, not only depend exclusively on the local geometry details, but also on the location in the cross-section of the rod bundle.

Spread Spectrum Communication System with Particle in a Box Electronic Circuit

A spread spectrum communication system based on the electronic model of the particle in a box system is proposed. This circuit allows a robust and simple electronic emulation of the mechanical behavior of the collisions of a particle inside a box, exhibiting rich chaotic behavior. The required nonlinearity to emulate the box walls is implemented in a simple way when compared with other analog electronic chaotic circuits. In this system, binary data stream information is transformed in the frequency modulated signal by the binary frequency shift keying (BFSK) modulator. The chaotic signal of the particle in a box electronic circuit is used to generate a broadband signal in the voltage controlled oscillator (VCO) of the transmitter. The frequency hopping signal send to receiver is generated by mixing the binary frequency shift keying and the broadband signal. The demodulation process is done when the VCOs of transmitter and receiver are synchronized by a phase lock loop (PLL) circuit. The performance of the demodulation process is verified through the eye pattern technique applied on the recovered bit stream. A binary data stream information was sent through a transmission channel with the following lengths: 1000 meters and 5000 meters. The experimental results demonstrated that the particle in a box electronic circuit can be used in a spread spectrum communication system.

The influence of talonavicular versus double arthrodesis on load dependent motion of the midtarsal joint

Today the most frequently used operative procedures in advanced arthritis of the hindfoot joints are isolated talonavicular arthrodesis and double arthrodesis (involving the talonavicular and calcaneocuboid joints, i.e. the Chopart joint). This in vitro study investigates whether the fusion of the talonavicular joint alone can provide the hindfoot, as well as a midfoot, with comparable biomechanical stability as the double arthrodesis does. Hence with the less-invasive intervention the same benefit in terms of pain reduction and better functionality could be achieved. In a series of ten fresh cadaver feet without any radiological pathologies, we measured the range of motion of different tarsal bones in three planes under axial stress. Every foot was loaded without arthrodesis, after talonavicular and after double arthrodesis, by charging tibia and fibula with a force of 350 N using a calibrated Instron® load frame. Each tarsal bone was marked with a K-wire and its motion was measured by registering the movement of the wire’s shade that was projected onto the surrounding walls of the trial box. Both operative procedures led to a considerable reduction of the motion of every marked bone to a mean of 18% of the preoperative value. In direct comparison of the two simulated arthrodeses we found for every bone and in every plane only minimal differences of the mean excursions of 1.0 mm on average. Both fusions lead to equal residual tarsal bone motion postoperatively, and provide the midtarsal joint as well as the subtalar joint with comparable biomechanical stability. Isolated talonavicular arthrodesis is a useful and effective alternative to double arthrodesis. It is the less complicated, less-invasive and functionally equivalent operative option for arthritic alterations of the hindfoot and transverse tarsal joint.

Distributions of Fines during Percolation Segregation for Varying Bed Depths in Binary Size Mixtures of Potash

The distribution profiles of percolated fines in binary size mixtures of blended fertilizer were evaluated during shear motion. Of the three main constituents used for preparing fertilizer blends, urea (near spherical shape), phosphate (somewhat aspherical), and potash (angular), potash was selected for experimentation because it is much more prone to segregation due to its angular shape. Based on particle size distribution of low analysis blends (such as 10-10-10), which are known to segregate, two absolute coarse size ranges of potash 3,500–4,000 μm and 2,800–3,500 μm, and three fine size ranges 2,000–2,360 μm, 1,700–2,000 μm, and 1,400–1,700 μm, were used to prepare binary mixtures. In all three different mixing proportions (coarse:fine = 67:33, 50:50, and 33:67) by weight of size ratios (coarse:fine particle size) 2.4, 2.0, 1.7, and 1.4 were formulated. The binary mixtures were tested for three bed depths (85 mm, 65 mm, and 42 mm) using the second-generation primary segregation shear cell (PSSC-II) at two strains (6% and 2%). At both strains, for all the size ratios and bed depths, the majority of segregated fines were concentrated near the moving walls of the shear box of PSSC-II. For size ratio of 2.4 at 6% strain, the segregated fines were most uniformly distributed for a bed depth of 85 mm and mixing ratio of 33:67 based on ANOVA and variance metrics analyses. Similar results were obtained for other size ratios at both strains.

Chaotic Communication Based on the Particle-in-a-Box Electronic Circuit

A secure communication system based on the error-feedback synchronization of the electronic model of the particle-in-a-box system is proposed. This circuit allows a robust and simple electronic emulation of the mechanical behavior of the collisions of a particle inside a box, exhibiting rich chaotic behavior. The required nonlinearity to emulate the box walls is implemented in a simple way when compared with other analog electronic chaotic circuits. A master/slave synchronization of two circuits exhibiting a rich chaotic behavior demonstrates the potentiality of this system to secure communication. In this system, binary data stream information modulates the bifurcation parameter of the particle-in-a-box electronic circuit in the transmitter. In the receiver circuit, this parameter is estimated using Pecora-Carroll synchronization and error-feedback synchronization. The performance of the demodulation process is verified through the eye pattern technique applied on the recovered bit stream. During the demodulation process, the error-feedback synchronization presented better performance compared with the Pecora-Carroll synchronization. The application of the particle-in-a-box electronic circuit in a secure communication system is demonstrated.

An experimental and numerical crashworthiness investigation of thermoplastic composite crash boxes

Dynamic crash tests are performed in order to determine the crash behavior of thermoplastic composite crash boxes. The specimens are made from woven fiberglass/polyamide plates. Recently developed thermoforming and welding methods are used to construct the crash boxes. The crash experiments show that the tubes are crushed in progressive manner start from one end of the tubes and delamination takes place between the layers. To better understand details of the crash process, the LS-DYNA explicit finite element code is used. Thin shell elements are used to model the walls of the crash box. To simulate the delamination between the composite layers, the tube walls are modeled as multi layer shell elements. An adequate contact algorithm is implemented to model the adhesion between the layers. Finally the multi design optimization MDO technique is implemented to find an optimum composite crash box that absorbs the most energy and has minimum weight. The crash performance of the optimum composite crash box is compared with an optimum aluminum tube.

Cotton Balls as an Oviposition Substrate for Laboratory Rearing of Phytophagous Stink Bugs (Heteroptera: Pentatomidae)

Studies were conducted to test the suitability of absorbent cotton as an oviposition substrate for phytophagous stink bugs (Heteroptera: Pentatomidae). In confined boxes, >80% of total egg masses of Euschistus heros (F.), Dichelops melacanthus (Dallas), and Thyanta perditor (F.) were laid on cotton; for Piezodorus guildinii (Westwood) and Chinavia impicticornis (Stal), >60%. However, Nezara viridula (L.) and Edessa meditabunda (F.) did not oviposit on cotton balls, but instead on the box walls, on filter paper, or on food. Newly hatched nymphs successfully (>95%) left the eggshells despite the presence of cotton fibers around the egg masses.

EM-Component-Based Design of Planar Circuits

In this article, the author starts with a quick tutorial about the ports used in EM analysis and how they are calibrated. Then, the paper discussed a new development -perfect internal port calibration. Finally, it concludes with a few examples illustrating the impact that perfect internal port calibration will have on microwave design.The author have also introduced a lot of new concepts in this article: perfectly calibrated box wall ports, perfectly calibrated (cocalibrated) internal ports, floating ground references, global ground references, several new component-based design methodologies, and baseline versus test structure validation.

Postnatal behavioral and physiological responses of piglets from gilts housed individually or in groups during gestation

Gestational housing of sows remains a controversial issue that may affect the well-being of both sows and piglets. Therefore, 2 types of gestational housing were used to evaluate the stress imposed on pregnant gilts by each system and the effects on the offspring by comparing production, physiology, and behavioral measures of the piglets. Forty-eight Landrace x Yorkshire gilts were randomly assigned to groups (G) of 4 per pen (n = 8 pens; 3.9 m x 2.4 m) or to individual stalls (S; n = 16 stalls; 2.21 m x 0.61 m). Gilts were moved into individual farrowing crates 5 d before the expected farrowing date. Piglets were weighed at birth, d 14, and d 35. Two barrows from each litter were weaned at d 14 (early weaning) and housed together in pens. Maintenance behaviors (head in feeder, drinking, lying, eating mash) were videotaped and observed for the first 3 d after weaning using a 10-min interval scan sampling. Belly nosing and play/fight interactions were recorded from video observations for 3 d postweaning. An isolation test (30-min duration) was performed on one piglet from each pen of barrows on d 35. Time spent lying, the number of jumps against test box walls, and grunts and squeals were recorded in real time. Salivary cortisol was collected at 30-min intervals from baseline, and 0, 30, 60, and 90 min posttest. Jugular blood was collected from 2 barrows from each litter on d 1, 7, 14, 17, 21, and 28. Plasma TNF-alpha was analyzed by ELISA, and haptoglobin, alpha1-acid glycoprotein, and immunoglobulin G were analyzed by radial immunodiffusion. More piglets from the S treatment needed to be fed a liquid feed at weaning and drank more frequently on d 2 postweaning (P < 0.05). Additionally, by d 35 piglets from S gilts had a lighter BW (10.3 kg) than G piglets (12.8 kg; P < 0.01). Piglets from S gilts also grunted more during the 30-min isolation test (number of grunts = 356) than G piglets (number of grunts = 138; P < 0.01). Salivary cortisol and immune measures were not different. These data show some behavioral and production differences between piglets from individually stalled gilts and group-housed gilts. Therefore, there may be production advantages to housing first parity gilts in groups.

A high-temperature superconducting bandpass filter with microstrip quarter-wavelength spiral resonators

A high-temperature superconducting bandpass filter at 408 MHz using microstrip quarter-wavelength spiral resonators is demonstrated. The quarter-wavelength spiral resonators were shorted to ground, as in a combline filter, via a grounding strip that is attached to the box wall by a number of aluminum bonding wires. The introduction of the normal metal wires does not introduce a measurable attenuation. The filter achieves a symmetrical quasi-elliptic characteristic by using two cross-coupling links. The experimental results of the filter are in very good agreement with the simulated ones.

Application of Conditioner Solution by Subsurface Emitters for Stabilizing the Surrounding Soil

Poor uniformity of water application by subsurface drip irrigation has been examined and some explanations are suggested in this paper. Use of soil conditioners for soil structure stabilization around subsurface drip irrigation pipes was suggested by the authors and tested in the laboratory. The conditioners preserve the structure of existing aggregated and may effectively reduce soil clogging. A silt loam soil was uniformly packed in a 13 0.83 0.15 m box. Two holes were dilled in the box wall through which two emitters were inserted, one for applying solution of soil conditioner and one as a control. Stabilization was achieved by applying two types of polymer solutions differing by their molecular weights through an emitter buried in a silt loam soil. A measured water volume was injected through the emitters into the soil and, after 48 h following irrigation, the box was dismantled. Gravimetric soil moisture content and aggregate water stability were measured in vertical and horizontal distances from the emitter. The highest stabilizing effectiveness was obtained with a volume of 1.5 L polymer solution at 5 g / L concentration, which was applied to the soil at an initial moisture content of 13%. The volume of stabilized soil increased with the volume of applied solution, but the volume ratio of stabilized soil to applied solution decreased with the increase in solution volume. A polymer of relatively low molecular weight was found less effective since a large portion of the solution was consumed by fast penetration into soil aggregates without improving the soil structure. The proposed method offers a simple and easy means for preparing a stabilized soil envelope around subsurface drip irrigation pipes, which may improve the long-term performance and uniformity of the application of these systems. Yet for some of these aspects, further field evaluation is needed, since the results of the study are from a laboratory experiment limited to one soil only.