Insulator Sleeve Research Articles

Novel accurate steady-state thermal resistance model for power chips embedded in TTSVs heat dissipation array

a novel oblique pyramid equivalent heat dissipation model is proposed for theoretically analyzing heat dissipation capacity of power chips with embedded TTSVs. Extra carefully researching correction of oblique thermal resistance, additional lateral thermal resistance, and thermal resistance of TSV insulation sleeve, the accurate theoretical thermal resistance model was established. Setting the FEA simulating results based on COMSOL Multiphysics as benchmark, heat dissipation effects of variation of radius of TTSV (r), thickness of the power chip (H0), and side length of the single cell (L0) have been numerically investigated. The maximum temperature relative error of the proposed model with FEA simulated results is not more than 0.2 %, 1 %, and 0.5 % for variation of r, H0, and L0, respectively. The proposed model has been theoretically and numerically proven to be effective and accurate.

Design of a New Type of Electrochemical Ceramic Membrane Oxygen Production System

In order to solve the problem that the existing oxygen production technology cannot simultaneously produce pure oxygen, high-purity oxygen, ultra-pure oxygen, and the modular expansion of oxygen production capacity, a new type of electrochemical ceramic membrane oxygen production system was discussed and developed. Through the design of the ceramic membrane stack, airflow distributor, heater, double spiral exchanger, thermal insulation sleeve, control panel, control box and auxiliary system in the electrochemical ceramic membrane oxygen generator, a modular oxygen production system is formed. The modular design can produce pure oxygen, high-purity oxygen and ultra-pure oxygen to meet various oxygen consumption needs. The electrochemical ceramic membrane oxygen production system is a new type of oxygen production technology. The main components have no moving parts, no noise, and no pollution. It can produce pure oxygen, high-purity oxygen and ultra-pure oxygen on site, with small size, light weight, and module combination which is suitable for convenient expansion and installation of oxygen consumption.

Compaction technology development for ITER In-vessel coil joints

Two types of ITER In-vessel coils (IVCs) are installed inside the vacuum vessel inner wall, behind blanket shield modules (BSMs), and near the plasma, namely: edge localized mode (ELM) and vertical stabilization (VS) coils. Overall, 27 ELM coils are distributed around the vacuum vessel inner wall, while one VS coil each is mounted above and below the plasma. Moreover, 176 IVC joints are used for joining the IVC coils, feeders, and feedthroughs, while 144 and 32 joints are used for joining the 27 ELM and two VS coils, respectively.The joints, which constitute a stainless steel (SS) sleeve, MgO insulation, and copper tube, show comparable performance to that of the conductor and can thus withstand severe conditions. Furthermore, the minimum available space for joint manufacturing is limited to 60 mm, which is a major obstacle. In joint manufacturing, two adjacent copper conductors are first welded via tungsten inert gas (TIG) welding, then the MgO insulation and sleeve will be applied. To maintain the insulation performance, the MgO insulation and SS sleeve should be compacted. Since compaction is one of the most important processes for joint manufacturing, this paper elucidates the development of compaction technology for IVC joints.

Research on the detection of silica/phenolic composite surface cracks using instantaneous high-power xenon lamp-induced chirp-pulsed radar thermography

In this present study, the high-power instantaneous xenon lamp-induced chirp-pulsed radar thermography was introduced to detect the surface crack of the silicon/phenolic composite which was widely used in the engine nozzle insulation sleeve. Two crack defect specimens were artificially made and detected by chirp-pulsed radar thermography to verify the detection ability of this approach. The cracks of two specimens were made by the diamond scribing process and laser ablation respectively. The differences between them were analyzed by the crack defect detection experiment. The crack defect made by the diamond scratching method is more consistent with the real situation according to the experimental results. The chirp-pulsed radar signal was extracted by the time/frequency signal extraction algorithms [cross-correlation (CC) and dual-orthogonal demodulation algorithms (DOD)]. The influence of parameters such as the power of xenon lamps, excitation frequency, reference pulse width or pulse time, and reference signal delay time on the detection results is mainly investigated by quantitative detection experiments. The results demonstrated that the CC peak and DOD amplitude are more sensitive than the phase when detected the surface crack of silica/phenolic composites. Meanwhile, the reflective phenomenon of the specimen’s surface has a great impact on the detection results. The larger the excitation parameters (such as the excitation frequency and the signal pulse width), the larger the contrast of the crack defect and the smaller the signal-to-noise ratio (SNR). The delay time of the reference signal has a small impact on the SNR and contrast of crack detection. In summary, instantaneous high-power xenon lamp-induced chirp-pulsed radar thermography can realize the reliable quantitative detection of surface cracks of silicon/phenolic composite.

Experimental study of the effect of circuit inductance on pinch-time in plasma focus MTPF2.5 KJ .

This paper investigates the effect of circuit inductance on pinch-time of plasma focus. The dense plasma focus is a plasma discharge powered by a capacitor bank. The Mather type Dense Plasma Focus is constructed in cylindrical geometry and is made up of coaxial anodes and cathodes with varying radiuses. An insulator sleeve separates the electrodes, and the cathode rode forms circles around the anode tube. Different parameters, such as geometry and structure of the anode bar, and decreasing inductance are involved in the optimization of plasma focus. One way to increase the gain and optimization of pulsed plasma systems is to reduce the inductance of the circuit. For this purpose, we investigate the effect of different values of total circuit inductance on pinch formation time. Experimental and simulation results are compared. the proposed system shows a decent functionality that if the inductance reduces, the efficiency of the system will increase.

Study on Thermal Insulation Measures for Construction of Reinforcement Sleeve Grouting Connection in Winter

In this paper, the feasibility of winter construction of steel sleeve grouting connection is studied, and two technical schemes of thermal insulation measures for winter construction are provided. This paper mainly introduces the experimental research work of sleeve grouting by simulating winter construction, including test scheme, test operation flow, test equipment and test data collection and analysis. It is concluded that the thermal insulation measures of prefabricated wall panel covering electric heating blanket, XPS insulation board and sleeve outer wall winding electric companion heat preservation are feasible. Finally, according to the actual project case to verify the feasibility of thermal insulation measures, so that the project can progress smoothly, for similar projects in winter construction to provide reference and reference.

Experiment and Modelling of Triangular Holes Array by Non-traditional Machining Process

Triangular holes array is a common structure of the specially shaped holes that can be used for various products in aerospace vehicles. These are commonly produced in the electrochemical machining (ECM) process. The high-quality and accuracy of a triangular grid are closely related to the processing parameters of cathode structure and sidewall insulation sleeve, power supply, electrolyte flow rate, feed speed, and machining gap. Simulations have been carried out to consider the influence of parameters including structure and dimension of the cathode, initial machining gap, feed speed, and current on the homogeneity of the flow field in the machining gap. Consequently, the modeling can support the design of the cathode. The paper is divided into two parts. Firstly, the tool cathode is simulated and fabricated. Secondly, the triangular holes array is produced by using the designed cathode tool. It was found that higher feed speed and lower machining gap increase the stability, accuracy, and efficiency of the machining process and the quality of the triangular holes array.

Effect of insulator surface conditioning on the pinch dynamics and x-ray production of a Ne-filled dense plasma focus

The dense plasma focus (DPF) can be an intense source of x rays, wherein the insulator sleeve strongly dictates the electrical breakdown, which subsequently affects the formation of a plasma sheath and a collapse phase. Experiments on a 25 kJ DPF (operated at 4.4 kJ) are carried out to demonstrate the influence of insulator surface morphology on the pinch structure, dynamics, and x-ray yield using a Ne fill. Two borosilicate insulators are directly compared, one with a smooth finish and the other machined with four circumferential grooves traversing the perimeter of the exterior insulator surface. Comparisons are made through same-shot imaging diagnostics of the evolving plasma sheath during breakdown, rundown, and at the pinch in addition to the time-resolved measurements of emitted x rays via filtered photodiodes. The presence of structures on the insulator sleeve reduces x-ray production across all fill pressures by a factor of 2.8 ± 2.4 on average and reduces the highest x ray producing shots by a factor of 5.5 ± 1.8. Observations of sheath asymmetry and inhomogeneity at lift-off are observed and correlated with subsequent observations of off-axis radial collapse. Taken together, this suggests that local variations in the insulator surface decrease the spatial uniformity of the sheath, leading to an azimuthally asymmetric focus, reduced electron densities, and, ultimately, degraded x-ray production.

Study on Thermal Insulation Measures for Construction of Reinforcement Sleeve Grouting Connection in Winter

<p>In this paper, the feasibility of winter construction of steel sleeve grouting connection is studied, and two technical schemes of thermal insulation measures for winter construction are provided. This paper mainly introduces the experimental research work of sleeve grouting by simulating winter construction, including test scheme, test operation flow, test equipment and test data collection and analysis. It is concluded that the thermal insulation measures of prefabricated wall panel covering electric heating blanket, XPS insulation board and sleeve outer wall winding electric companion heat preservation are feasible. Finally, according to the actual project case to verify the feasibility of thermal insulation measures, so that the project can progress smoothly, for similar projects in winter construction to provide reference and reference.</p>

Improvement of Electrochemical Trepanning by Using a Pictographic Insulation Sleeve

Improvement of Electrochemical Trepanning by Using a Pictographic Insulation Sleeve

Experimental investigation of the effect of insulator sleeve length on the time to pinch and multipinch formation in the plasma focus facility

The length of insulator sleeve is varied to investigate its effect on the pinch formation in the plasma focus facility. In this paper, the effect of insulator length on the time to pinch at various pressures and working voltages in the 1.15 kJ Mather type plasma focus is investigated. The results show that with 4.5 cm insulator length the time to pinch at all pressures is minimum. Other results also confirm that with increasing of pressure the time to pinch is increased. Moreover, with increasing working voltage the time to pinch is decreased. Pictures, captured using a digital single lens reflex (DSLR) Canon EOS 7D system, show that multipinch phenomenon is formed.

Influence of Krypton Seeding on DD Fusion Neutron Production: Evaluation Methodology for Plasma Focus Optimization

A sub-kilo-Joule plasma focus device (FMPF-3, 14 kV/235 J) was operated with deuterium–krypton admixtures (of 1, 2 and 5 % Kr by volume) to study the influence of admixture ratio on neutron yield (Yn). Experiments were performed for different insulator sleeve lengths and cathode geometries. The results reveal that for a carefully optimized electrode geometry the highest average neutron yield is obtained with pure deuterium as the operating gas, whereas krypton seeding leads to a reduction in Yn. We argue that the electrode geometry and electrical coupling play critical roles in determining the influence of gas admixtures; and that for an optimized plasma focus device D2-Kr admixtures may give little or no neutron yield enhancement relative to pure D2 operation and so the admixture operation is an evaluation methodology to determine the level of optimization of device geometry.

Insects are electrified in an electric field by deprivation of their negative charge

An electric field screen (EF‐screen) is a physical device for excluding pest insects from greenhouses and warehouses to protect crops during their production and storage periods. In this study, a simple version of the EF‐screen, an insulated conductor iron wire (ICW) paralleled to an earthed net, was constructed to effectively observe the attraction of test insects in relation to their electricity release. The ICW was negatively charged to dielectrically polarise the insulator sleeve of the ICW: negatively on the outer surface and positively on the inner conductor wire surface of the sleeve. The negative surface charge of the ICW caused an electrostatic induction in the earthed net and a resultant positive charge at the ICW‐side surface of the net. An electric field formed between the ICW (negative pole) and earthed net (positive pole). Insects were attracted to the ICW when they were placed onto the earthed net. A vital step for the attraction was the creation of a transient bioelectric discharge from an insect. During this discharge, an electric charge of the insect was transferred to the earthed net. Eventually, the insect became net positive and was then attracted to the ICW. The magnitude of the current increased in direct proportion to the increase in voltage applied to the ICW, and the attraction force was directly proportional to the increase in the electric current. Larger voltages were necessary to attract much larger insects because larger insects were stronger and therefore more able to escape from the ICW attraction. Similar results were obtained for a wide range of pest insects belonging to different taxonomic groups (8 orders and 15 families). This study demonstrated that transient bioelectric discharge is common in insects and can be utilised to create an electrostatic force capable of moving insects in a generated electric field.

Influence of Pyrex Insulator Thickness and it’s Length on Hard X-Ray Intensity in APF Plasma Focus Device

In order to improve the HXR emission from APF plasma focus device we have investigated the effect of insulator sleeve outer diameter (O.D.) and its length. Fourteen different insulator sleeve geometries at three different filling gas pressures of 6, 7 and 8 Torr of neon are used in the present investigation. The average HXR yield, measured using scintillation detector, has been found to increase with the increase in insulator sleeve O.D. from 31 to 34 mm. Further increase in insulator sleeve diameter to 37 mm, however, decreased the HXR yield. The highest magnitude of 234.5 kA was achieved for 34 mm O.D. of sleeve at filling gas pressure of 7 Torr and voltage of 12 kV.

A newly devised electric field screen for avoidance and capture of cigarette beetles and vinegar flies

A bifunctional electric field screen was proposed to physically exclude insect pests from warehouses. The screen consists of insulated iron wires (ICW) arranged in parallel and two earthed conductor nets placed on both sides of the ICW. A negative charge (0.1–8.0 kV) was applied to the insulated wires with a voltage generator to polarize an insulator sleeve used to cover the wire, negatively on the outer surface and positively on the inner conductor wire surface of the sleeve. The negative surface charge of the ICW caused an electrostatic induction in the earthed nets and an opposite charge on the net surfaces facing the ICW. An electric field formed in a space between the ICW and the earthed net, and the field strength increased in direct proportion to increasing voltages applied to the ICW. Adults of the test insects (cigarette beetle ( Lasioderma serricorne) and vinegar fly ( Drosophila melanogaster)) reaching the outer surface of the earthed net were deterred from entering the inside of the charged screen, whereas all insects immediately passed through the screen when the ICW was not charged. This avoidance was directly proportional to the increase in the voltage. In addition, the capability of the screen to capture insects that enter inside the screen was proven by introducing insects into the space between the ICW and the earthed net. Strong capture was observed when the ICW was negatively charged with more than 4.1 kV, under which conditions a short-term electric current (peaking at 0.3–0.6 μA, for 3 min) occurred transiently. This electric current was due to the release of electricity from the insects, giving a net overall positive charge to the insects, which therefore were attracted more strongly to the negatively charged ICW. A test using an attractant-set chamber showed that the insects were completely prevented from passing through the charged screen, in contrast to a rapid transfer of all insects when the screen was not charged. Thus, the present results show that the described screen is a promising physical tool for controlling insect pests in warehouses.

Effect of insulator sleeve material on the x-ray emission from a plasma focus device

The effect of insulator sleeve material on x-ray emission from a 2.3 kJ Mather type plasma focus device operated in argon-hydrogen mixture is investigated. The time and space resolved x-ray emission characteristics are studied by using a three channel p-i-n diode x-ray spectrometer and a multipinhole camera. The x-ray emission depends on the volumetric ratio of argon-hydrogen mixture as well as the filling pressure and the highest x-ray emission is observed for a volumetric ratio 40% Ar to 60% H2 at 2.5 mbar filling pressure. The fused silica insulator sleeve produces the highest x-ray emission whereas nonceramic insulator sleeves such as nylon, Perspex, or Teflon does not produce focus or x-rays. The pinhole images of the x-ray emitting zones reveal that the contribution of the Cu Kα line is weak and plasma x-rays are intense. The highest plasma electron temperature is estimated to be 3.3 and 3.6 keV for Pyrex glass and fused silica insulator sleeves, respectively. It is speculated that the higher surface resistivity of fused silica is responsible for enhanced x-ray emission and plasma electron temperature.

Experimental Study of Current Discharge Behavior and Hard X-ray Anisotropy by APF Plasma Focus Device

Amirkabir (APF) is a new Mather-type plasma focus device (16 kV, 36 μf, and 115 nH). In this work we present some experimental results as variation of discharge current signal respect to applied voltage at the optimum pressure, focusing time of plasma versus gas pressure, and variations of current discharge with different insulator sleeve dimensions. As we prospected optimum pressure tending to increase as we tried to higher voltage levels. The time taken by the current sheath to lift-off the insulator surface and therefore quality of pinched plasma depends on the length of the insulator sleeve. The results show that the insulator diameter can influence on pinch quality. Behavior of hard X-ray (HXR) signals with the pressure and also anisotropy of HXR investigated by the use of two scintillation detectors. The distribution of HXR intensity shows a large anisotropy with a maximum intensity between 22.5° and 45° and also between −22.5° and −67.5°.

An electric dipolar screen with oppositely polarized insulators for excluding whiteflies from greenhouses

A new electrostatic insect-proof screen (electric dipolar screen) was developed using insulated conductor wire. Copper conductor wire is encased in a flexible transparent vinyl insulator sleeve and charged with an electrostatic voltage generator. Paired insulated conductor wires were placed in parallel with 5 mm of separation and oppositely charged with 15 kV DC using separate electrostatic voltage generators. A negatively charged conductor wire polarizes the insulator negatively at the outer surface and positively on the conductor side, and a positively charged conductor wire polarizes vice versa. A pair of insulated conductor wires with opposite surface charges was used as an electric dipole. An electric dipole creates an electrostatic force from positive to negative poles. This force was harnessed to trap whiteflies entering greenhouses. Dipolar wires were attached in parallel to a frame to construct an electric dipolar screen that could be fitted to greenhouse windows. The screen prevented adult whiteflies from passing through spaces (up to 30 mm) between the wires of the screen, and tomato plants inside remained free of whiteflies throughout the entire 3-week experiment, in contrast to heavy infestation of all plants in the uncharged area. Thus, the electric dipolar screen is a promising tool to physically exclude flying whiteflies from greenhouses.

Effect of the insulator length on Mather-type plasma focus devices

Abstract Plasma focus devices were studied in order to identify the design parameters and logical relationships that exist among device components. A quantitative parameter has been defined as the ratio of insulator sleeve length to the radial distance between the electrodes, “ L ins / ( b − a ) ”. It is demonstrated that the Mather-type plasma focus device, operated in the optimum regimes, has a remarkably low sensitivity to this parameter which relates the insulator length to the electrodes geometry. A modification factor for the axial velocity in different PF devices has been introduced to maintain the value of the “ q ” parameter within the range of zero to one.

Depleted uranium (U23892) induced preionization for enhanced and reproducible x-ray emission from plasma focus

The effect of preionization induced by depleted uranium (U23892) around the insulator sleeve on the x-ray emission of (2.3–3.9kJ) plasma focus device is investigated by employing Quantrad Si p-i-n diodes and a multipinhole camera. X-ray emission in 4π geometry is measured as a function of charging voltage with and without preionization. It is found that the preionization enhances CuKα and total x-ray yield about 100%, broadens the x-ray emission pressure range and x-ray pulse width, and improves shot to shot reproducibility of plasma focus operation. The pinhole images of x-ray emitting zones indicate that dominant x-ray emission is from the anode tip.