Filament Heating Research Articles

Experimental investigation of thermal runaway behavior and propagation inhibition of lithium-ion battery by immersion cooling

Understanding the impact of immersion cooling on thermal runaway (TR) behavior and its inhibitory effect on thermal runaway propagation (TRP) is crucial for its practical application. This study explores immersion cooling for individual cells and battery modules, examines the TR behavior of 18,650 single cells at various immersion depths and states of charge (SOC) using filament heating, and investigates TRP between cells. Immersion cooling with a depth of 70 mm significantly extends the interval between the rupture of the battery safety valve and the TR trigger from 70 s (at a 20 mm depth) to 312 s, while reducing the peak TR temperature to 306 °C. Additionally, cells with 100 %, 75 %, and 50 % SOC show that higher battery capacity increases the risk of TR and thermal hazards. TRP experiments demonstrate that immersion cooling can inhibit TRP between cells, though safety valves of adjacent cells in 100 %, 75 %, and 50 % SOC battery modules still ruptured, with peak temperatures reaching 118.2 °C, 121.4 °C, and 111.5 °C respectively, posing a potential TR risk. This study highlights the TR behavior of single cells at different immersion depths and confirms that immersion cooling can inhibit TRP, providing valuable insights for the future application of immersion cooling in lithium battery thermal management systems.

Effective gate length determination of AlGaN/GaN HEMTs from direct measurements of thermal signatures

Determining junction temperature and two-dimensional temperature profile is critical for high-power GaN-based high electron mobility transistors to optimize performance, improve device reliability, and better thermal management. Here, we have demonstrated that resistance temperature detectors of the same material as the gate contact delineated between gate-to-source and gate-to-drain regions can accurately profile the temperature along the channel. The temperature profile is asymmetric and skewed toward the drain side, and the degree of asymmetry is used to determine the effective gate length experimentally. A two-dimensional thermodynamic model along with drift-diffusion transport matches well with the experimental data, validating the temperature profile and effective channel length extraction under bias. The vertical depth profiling of the temperature is also determined by identifying the isothermal profile through the resistance temperature detectors. The isothermal lines are largely circular in the GaN region from isotropic two-dimensional heat diffusion, with the pinch-off region acting as a heating filament. The isothermal circular profile turns elliptical in the SiC substrate due to its higher thermal conductivity.

Low Energy Consumption GeTe Phase-Change Radio Frequency Switch With Direct Heating of Conductive Filament

Low Energy Consumption GeTe Phase-Change Radio Frequency Switch With Direct Heating of Conductive Filament

Exposure hazards of particles and volatile organic compounds emitted from material extrusion 3D printing: Consolidation of chamber study data

Ultrafine particles and volatile organic compounds (VOCs) have been detected from material extrusion 3D printing, which is widely used in non-industrial environments. This study consolidates data of 447 particle emission and 58 VOC emission evaluations from a chamber study using a standardized testing method with various 3D printing scenarios. The interquartile ranges of the observed emission rates were 109–1011 #/h for particles and 0.2–1.0 mg/h for total VOC. Print material contributed largely to the variations of particle and total VOC emissions and determined the most abundantly emitted VOCs. Printing conditions and filament specifications, included printer brand, print temperature and speed, build plate heating setup, filament brand, color and composite, also affected emissions and resulted in large variations observed in emission profiles. Multiple regression showed that particle emissions were more impacted by various print conditions than VOC emissions. According to indoor exposure modeling, personal and residential exposure scenarios were more likely to result in high exposure levels, often exceeding recommended exposure limits. Hazardous VOCs commonly emitted from 3D printing included aromatics, aldehydes, alcohols, ketones, esters and siloxanes, among which were various carcinogens, irritants and developmental and reproductive toxins. Therefore, 3D printing emits a complex mixture of ultrafine particles and various hazardous chemicals, exposure to which may exceed recommended exposure limits and potentially induce acute, chronic, or developmental health effects for users depending on exposure scenarios.

How pulse energy affects ignition efficiency of DBD plasma-assisted combustion

This work aims to find how coupled energy per pulse influences the ability of a pulsed dielectric barrier discharge (DBD) plasma to ignite fuel-lean methane–air flow. For that, experiments are performed on a custom-built DBD flow reactor with a variable dielectric thickness and the discharge is operated by bursts of 10 ns duration pulses at 3 kHz repetition rate. With an increase in dielectric thickness, we observe that the coupled energy per pulse decreases even though applied voltage conditions are similar and so more pulses are required to ignite the lean mixture. Interestingly, we observe a significant increase in the minimum ignition energy (MIE) with an increase in the thickness beyond 3 mm. Moreover, the ignition kernel growth rate is much slower in the thicker dielectric cases even though total energy coupling per burst is similar. This phenomenon is investigated further by evaluating plasma parameters using electrical and optical diagnostics. Effective dielectric capacitance, discharge current, and voltage drop across the gas gap are derived from an equivalent circuit analysis, whereas plasma gas temperature and effective reduced electric field ( E/N ) are estimated from optical emission spectroscopy. From these analyses, we conclude that a thicker dielectric limits the discharge current and so the plasma filament temperature. For more than 3 mm thick dielectric cases, the filament heating per pulse is too low to achieve strong enough plasma pulse-to-pulse coupling which eventually leads to higher MIE and slower ignition kernel growth rate or the inability to ignite at all.

Mechanisms involved in the antinociceptive and anti-inflammatory effects of xanthotoxin.

Xanthotoxin (XAT) is a natural furanocoumarin clinically used in the treatment of skin diseases such as vitiligo and psoriasis. Recent studies have also investigated its effects on anti-inflammatory, anti-cognitive dysfunction, and anti-amnesia as a guideline for clinic application. However, little is known about its effects on pain relief. Here, we tested the analgesic effects of XAT in serious acute pain and chronic pain models. For acute pain, we used hot-, capsaicin- and formalin-induced paw licking. Nociceptive threshold was measured by mechanical stimuli with von Frey filaments. For chronic pain, we injected complete Freund's adjuvant (CFA) into the mice's plantar surface of the hind paw to induce inflammatory pain. Heat and mechanical hyperalgesia were evaluated by radiant heat and von Frey filament tests, respectively. To investigate the mechanisms underlying the analgesic effect of XAT, we used calcium imaging and western blot to assess transient receptor potential vanilloid 1 (TRPV1) activity and expression in isolated L4-L6 dorsal root ganglion (DRG) neurons. Haematoxylin and eosin (HE) staining, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA) were used to examine immune cell recruitment and proinflammatory factor release from skin tissue from paw injection sites. Our results demonstrated that XAT not only reduced acute pain behaviors generated by hot, capsaicin, and formalin but also attenuated CFA-induced heat and mechanical hyperalgesia. The analgesic activity of XAT may be achieved by controlling peripheral inflammation, lowering immune cell infiltration at the site of inflammatory tissue, reducing inflammatory factor production, and therefore inhibiting TRPV1 channel sensitization and expression.

Thermally robust and highly stable method for splicing silica glass fiber to crystalline sapphire fiber.

This research reports an advancement in splicing silica glass fiber to sapphire single-crystal optical fiber (SCF) using a specialized glass processing device, including data that demonstrate the thermal stability of the splice to 1000°C. A filament heating process was used to produce a robust splice between the dissimilar fibers. A femtosecond laser is used to inscribe a fiber Bragg gratings sensor into the SCF to measure the high-temperature capabilities and signal attenuation characteristics of the splice joint. The experimental results demonstrate that the proposed splicing method produces a splice joint that is robust, stable, repeatable, and withstands temperatures up to 1000°C with a low attenuation of 0.5dB. The proposed method allows placement of SCF-based sensors in the extreme environments encountered in various engineering fields, such as nuclear, chemical, aviation, and metals manufacturing, to enable improvements in process monitoring, product quality, and production efficiency.

Heating filament with Self-Regulation Temperature by Coating a Metallic Yarn with a Conductive Polymer Composite

Nowadays, the heating textiles are used in many fields of applications as medicine or comfort. The heating property for the most part of these textiles was ensured by electrical conductive fiber as metallic yarn thanks to Joule Effect. A challenge for heating textile is to have an electrical conductive fiber which has a temperature self-regulation at the comfort temperature. Thanks to this temperature self-regulation, the heating textile reaches more autonomy. To develop this kind of textile, conductive polymer composite (CPC), which is the combination between an insulating polymer and electrical conductivity nanofillers [1], is made by melt spinning. The temperature self-regulation is provided by the positive temperature coefficient (PTC) effect, which allows switching between an electrical conductivity state and an insulating state when the CPC is close to a transition phase temperature (glass transition temperature or melt temperature). However, when the PTC effect can take place at the melting point, the mechanical properties are not involved. So to maintain the final product an immiscible polymer blend was used: one polymer was the CPC and the second polymer was an insulating polymer with a higher melting point than the target temperature. In fact, the CPC involve the electrical conductivity and the PTC effect, whereas the insulating polymer involves the mechanical properties. However, a high electrical conductivity is necessary to reach the comfort temperature (defined around 42°) by Joule Effect. So to reach this temperature, the coating on a metallic yarn by the conductive immiscible polymer blend was used. The electrical conductivity of this product was improved by the metallic yarn and the self-regulating temperature by the PTC effect of the immiscible polymer blend (figure 1). In this paper the immiscible polymer blend used is a polycaprolactone (PCL) filled with multiwall carbon nanotubes (MWCNT) and a polypropylene (PP). In fact, in a previous paper the co-continuity and the selective localisation of the fillers in the PCL for this blend was studied [2]. The influence of the thickness CPC coating and the influence of the structure of metallic yarn were studied on the electrical conductivity, the Joule Effect and PTC effect.

Fabrication and Testing of an Electric Oven

This research was carried out with the aim to fabricate and test an electric oven from locally available materials, with the objectives to fabricate electric oven for baking and cooking, electric oven that will be affordable compare to the ones obtainable in the market and to discourage deforestation in our communities. The materials used were metal plate 6.543mm, iron rod 12mm, welding electrodes, electric heat filament, mesh wires, connecting wires 4mm, temperature controlling device (analogue). The iron rods were used to construct electric oven frame in the form of a box with the provisions of inner walls where lagging materials was installed and finally electric welding was used to join the metal plates and the frame. The fabricated electric oven was tested and it was observed that it works with effectiveness and high performance from the result obtained.

Deposition of titanium on steel using hot-filament metal deposition technique

There was highly need to coat the structural steel 1018 with thin layer of Titanium. The conventional method of coating thin layers is spattering but it was very difficult to layer thickness with some nanometres. Spattering method used for hours to deposition nearly about 50 nm of Titanium at very high voltages of target reach to 1250 V. Thin layer of titanium film was successfully deposited on steel substrate. The layer thickness of titanium could reach up to 500 nm with filament heating temperature of 1400 °C and heating time of 45 min which is superior compared to DC sputtering and faster in thickness of coating about twenty times. The deposited layer was investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The resulted phases were evaluated using x-rays diffraction (XRD). The adhesion force was up to 200 psi.

Pain-relieving effects of Lawsonia inermis on neuropathic pain induced by chronic constriction injury.

The aim of this study was to determine the role of Lawsonia inermis (L. inermis) extract in the chronic constriction injury (CCI)-induced neuropathic pain. Following CCI surgery, L. inermis extract (250mg/kg and 500mg/kg) and gabapentin (100mg/kg) were administered intraperitoneally for 14 consecutive days. Heat hyperalgesia and allodynia were assessed by radiant heat, aceton drop, and von frey filament tests, respectively. Rat pain behaviors were evaluated on -1sh, 3rd, 5th, 7th, 10th and 14th days post CCI surgery. At the end of the study, the spinal levels of malondialdehyde (MDA), total thiol, IL1-β, and TNF-α were estimated. Treatment of L. inermis extract reversed the decreased level of thiol and the elevation of MDA level in the spinal cord of CCI rats. Besides, L. inermis extract treatment decreased the elevation of inflammatory markers including IL1-β, and TNF-α in the spinal cord of CCI rats. These results indicated that L. inermis has potential neuroprotective effects against CCI induced neuropathic pain due to its anti-oxidant, and anti-inflammatory effects.

Monitoring of Particulate Matter Emissions from 3D Printing Activity in the Home Setting.

Consumer-level 3D printers are becoming increasingly prevalent in home settings. However, research shows that printing with these desktop 3D printers can impact indoor air quality (IAQ). This study examined particulate matter (PM) emissions generated by 3D printers in an indoor domestic setting. Print filament type, brand, and color were investigated and shown to all have significant impacts on the PM emission profiles over time. For example, emission rates were observed to vary by up to 150-fold, depending on the brand of a specific filament being used. Various printer settings (e.g., fan speed, infill density, extruder temperature) were also investigated. This study identifies that high levels of PM are triggered by the filament heating process and that accessible, user-controlled print settings can be used to modulate the PM emission from the 3D printing process. Considering these findings, a low-cost home IAQ sensor was evaluated as a potential means to enable a home user to monitor PM emissions from their 3D printing activities. This sensing approach was demonstrated to detect the timepoint where the onset of PM emission from a 3D print occurs. Therefore, these low-cost sensors could serve to inform the user when PM levels in the home become elevated significantly on account of this activity and furthermore, can indicate the time at which PM levels return to baseline after the printing process and/or after adding ventilation. By deploying such sensors at home, domestic users of 3D printers can assess the impact of filament type, color, and brand that they utilize on PM emissions, as well as be informed of how their selected print settings can impact their PM exposure levels.

Control of Plasma Parameters by Hot Ionizing Electrons Using a Mesh Grid

In this article, we are reporting about the effect of energy and number density of hot primary electrons on plasma parameters in a new experimental configuration of a double plasma device. Here, we have controlled the plasma parameters in two plasma regions by a single discharge circuit. The discharge voltage is applied between hot filaments and a mesh grid. The energy of the hot primary electrons is increased by increasing the discharge voltage, and their number density is increased by increasing the filament heating voltage. It has been observed that the variations in plasma parameters are significant when the number density of primary electrons is increased.

Development of a small-scale reactor for upgraded biofuel pellets

The comprehensive investigation of a pyrolysis reactor has been conducted on the basis of thermal engineering design. The gas dynamics, thermodynamic, and psychrometric behaviour of the producer gas have been thoroughly assessed. The pilot-scale reactor has been programmed to operate at the temperature 973 K in the absence of an inert medium. The concentric casing of the heating filament has been used as an external source of energy. The experimental task is divided into two parts: upgradation of biomass and the decomposition of pellets in a developed small-scale pyrolysis unit for the possible gas, char, and pyrolysis oil generation. The fuel upgradation is performed via quasi-static torrefaction of pine pellets using Joule heating in the presence of nitrogen gas. The volumetric gas of nitrogen flowing across the improvised furnace is 0.70 L·min−1. The obtained results are compared with the wood pellets. The unsaturated producer gas has been found to vary accordingly to the following gas equation pv0.25=C and pv−0.69=C for the processed pine pellets and wood pellets, respectively. A relative increase of 21.00% has been seen while running the reactor with the processed pine pellets. The percentage yield of the pyrolytic oil for the processed pine and wood pellets is 10.48% and 30.00% respectively. The flame temperature and adiabatic flame temperature of the producer gas (processed pine) is lowered by 8.10% and 17.00% respectively. The energy yield of processed pinechar is found to be 122.58% higher than that of wood char.

Extinguishment of hot cathode discharges by space-charge and surface magnetic effects

Emission characteristics of a directly heated, rod-shaped LaB6 hot cathode has been studied in a multi-dipole confinement device. It is found that contrary to predictions from the conventional space-charge limited emission theory, emission current is not simply limited to a maximum value but eventually extinguished by space-charge related effects. In addition, directional preference of electron emission towards the positive lead of the applied heating voltage can be visibly observed. Results suggest that thermionically emitted electrons trapped in the virtual cathode are pumped towards the high voltage lead of the applied heating, and that the magnetic effects for filament heating currents exceeding 50 A may be the underlying mechanism of extinguishment; that is, the gyromotion of surface emitted electrons for sufficiently great heating currents may prevent electrons from escaping the virtual cathode. Geometrical effects are also briefly discussed.

Combination of Filament-Heating and Cavity-Driven Circuit With Gain-Frequency Regulation Control for Magnetrons

This article proposes the combination of filament-heating and cavity-driven circuit with gain-frequency regulation control for magnetrons. This article is motivated because some existent magnetron-driven systems often adopted two resonant circuits individually for filament heating and cavity driving, resulting in limited flexibility of power delivery and modulation. Therefore, this article develops an integrated resonant power circuit that excels at the capability improvement of filament heating and cavity driving in the same time such that the design process and power conversion can be simplified while the output power is effectively induced. Meanwhile, by considering that the microwave source emission in the magnetron is often affected by the variation of internal impedance, this article includes a gain-frequency tracking control. Through this way of controller design, both heating power and cavity power are found to be well regulated and the constant-power operation can be better achieved. To confirm the effectiveness of this magnetron-driven design, both circuit simulation and hardware realization are accomplished. Analysis results and experimental outcome support the practicality of the approach, benefiting the realization of microwave energy applications.

DCM 직렬 공진형 컨버터 기반의 필라멘트 전원 장치의 설계

For the magnetron, gyrotron and electron beam welder, which is the applications of the technology applying high voltage to thermal electrons, the power supply is required to heat filament for emission of thermal electrons. This paper describes the design of filament power supply, whose maximum output voltage is 17 V and maximum output current is 10 A based on the series resonant converter(SRC) operating in discontinuous conduction mode(DCM). The design and operating characteristics were verified by the PSPICE simulation and experimental results with resistor load. Also experimental results with a simulated load, which simulates characteristic of filament load whose impedance increases with increasing temperature, confirmed characteristics of the current source that has a constant output current on the fluctuated load condition.

Hybrid Control over the State of a 3D Printer

The tools for soft computational technologies are based on the fuzzy systems, models of fuzzy neural networks, genetic algorithms, etc., which have advantages and drawbacks. In this paper, these tools are considered as applied to a 3D printer. From the point of view of control theory, a 3D printer is a complex nonlinear object, the mathematical description of which is a priori known, with one input and several outputs. During the operation of a 3D printer, it is required to provide continuous monitoring of such parameters as temperature of filament heating, rotation speed of a dc motor for feeding the filament to the extruder, and linear replacement of the carriage of a 3D printer. The operation of circuits is regulated by the controller of state, which, by analyzing the deviations of parameters, synchronously logically continuously controls the temperature of filament heating, feeding the filament to the extruder, and linear replacement of the carriage. The target function for all the circuits takes a given value of the adjustable parameters. The hybrid (fuzzy-neural) control over a 3D printer is based on the designing of a state controller using the special fuzzifier with the use of asymmetric sigmoid functions and the formation of layers to carry out fuzzy implication. The conversion of fuzzy information into determined information is carried out in a converter (decoder) that controls the printer voltage within the given range.

PID Modeling and Experiment of the Hot Test of Gyrotron Traveling Wave Tubes

The establishment of an automatic hot test platform is one of the important conditions to ensure the safe and stable operation for the gyrotron traveling wave tubes (gyro-TWTs). In order to verify the reliability of the controlling strategies used in the long period hot test of a high peak/average power gyro-TWT, the control process of the cathode-anode beam voltage and current is described by a mathematical model based on a proportional—integral—derivative (PID) controller. The beam voltage is controlled by the high-voltage power supply and the beam current is regulated by the high-voltage power supply and filament heating power. A mathematical model of the PID controller is developed and evaluated by the MATLAB to analyze the performance of the system. The comparison between the experimental and modeling results show that the second-order inertia model with time delay can express the control process of the beam voltage and current well. The PID controlling theory can be used to model the control process of the hot test of a gyro-TWT with digital signal, so that the damage of the immature strategy is prevented.

Activation of spinal Extacellular Signal‐Regulated Kinases and c‐jun N‐terminal kinase signaling pathways contributes to morphine‐induced acute and chronic hyperalgesia in mice

This study investigated the activation of mitogen-activated protein kinases in the spinal dorsal horn to explore the mechanisms underlying morphine-induced acute and chronic hyperalgesia in mice. Male adult mice were given a single subcutaneous injection (SC) of morphine (1 μg/kg) or twice-daily administration of morphine (10 mg/kg/day) for 8 days. Thermal hyperalgesia and mechanical allodynia were assessed using the radiant heat and von Frey filament test. Levels of phospho (p)-extracellular signal-regulated kinases (p-ERK), p-c-Jun N-terminal kinase (p-JNK), p-p38, p-PKCγ, N-methyl-d-aspartate receptor (NMDAr), and c-Fos protein in the spinal dorsal horn were examined by Western blot assays. A single ultra-low dose or repeated administration of morphine induced hyperalgesia in mice and caused a significant increase in the levels of p-ERK and p-JNK, but not p-p38, in the spinal dorsal horn. The level of c-Fos protein was significantly elevated following administration of morphine. The protein levels of p-PKCγ and NMDAr subunits (NR2B and NR2A) were also altered. Pretreatment with the NMDAr antagonist MK-801 or the protein kinase C (PKC) inhibitor calphostin C (CC) suppressed the morphine-induced increase in p-ERK, p-JNK, and c-Fos. Administration of MK-801 and CC also relieved morphine-induced hyperalgesia. These findings suggest that activation of the spinal ERK and JNK signaling pathways contribute to morphine-induced acute and chronic hyperalgesia in mice.