Temperature-sensitive Components Research Articles

Investigation of physics-informed deep learning for the prediction of parametric, three-dimensional flow based on boundary data

The placement of temperature sensitive and safety-critical components is crucial in the automotive industry. It is therefore inevitable, even at the design stage of new vehicles, that these components are assessed for potential safety issues. However, with increasing number of design proposals, risk assessment using Computational Fluid Dynamics (CFD) quickly becomes expensive. We therefore present a parameterized surrogate model for the prediction of three-dimensional flow fields in aerothermal vehicle simulations. The proposed physics-informed neural network (PINN) design is aimed at learning families of flow solutions according to a geometric variation. The novelty of our method compared to existing works in the field of PINN lies in the extension of parametric flow prediction to three-dimensional space by applying a mini-batch based Quasi-Newton optimization. We contribute a parametric minibatch training algorithm which enables the utilization of the large datasets necessary for the three-dimensional flow modeling. Further, we introduce a continuous resampling algorithm that allows to represent domain variations, while operating on one static dataset of reduced size. In scope of this work, we could show that our nondimensional, multivariate scheme can be efficiently extended to predict the velocity and pressure distribution in three-dimensional space for different design scenarios and geometric scales. Every feature of our methodology is tested individually and verified against conventional CFD simulations. Finally, we apply our proposed method in context of an exemplary real-world automotive application.

Thermal flux manipulation on the silicon photonic chip to suppress the thermal crosstalk

The integration density of silicon photonic integrated circuit (PIC) is ultimately constrained by various crosstalk mechanisms on the chip. Among them, the most prominent limiting factor is the thermal crosstalk due to the wide use of the thermo-optic effect. High-density silicon PICs strongly demand an advanced structure with better thermal crosstalk suppression ability than the traditional air isolation trench. Inspired by the thermal-metamaterial based on the scattering-cancellation method, we demonstrate a closed heat shield (CHS) structure on a silicon PIC chip, which can manipulate the thermal flux to bypass the temperature-sensitive silicon photonics components. The on-chip CHS structure is a bilayer cylindrical shell fabricated by the standard silicon photonics processing flow. Its outer and inner shell layers are formed by a 6-μm-wide interconnection metal and 4-μm-wide air trench, respectively. Plenty of temperature-sensitive micro-ring resonators inside the CHS are used to probe the temperature profile. The measurement results show that the CHS can reduce the local temperatures by 50%/44%/36% at the locations 29/41/83 μm away from the external heater. In contrast, the conventional air trench of the same dimension reduces the local temperatures by 32%/28%/21% at the same positions. In addition, the response time of the thermal field inside the CHS is around one-half of that in the conventional air trench. Furthermore, the simulation result indicates that if the outer shell of the CHS can contact with the silicon substrate by utilizing the through-silicon-via structure, the thermal crosstalk suppression ability can be improved significantly.

Low-Temperature Wafer-Level Bonding with Cu-Sn-In Solid Liquid Interdiffusion for Microsystem Packaging

This work demonstrates the potential use of Cu-Sn-In metallurgy for wafer-level low-temperature solid-liquid interdiffusion (LT-SLID) bonding process for microelectromechanical system (MEMS) packaging. Test structures containing seal-ring shaped SLID bonds were employed to bond silicon and glass wafers at temperatures as low as 170 °C. Scanning acoustic microscopy (SAM) was utilized to inspect the quality of as-bonded wafers. The package hermeticity was characterized by cap-deflection measurements and evaluated through finite element modelling. The results indicate the bonds are hermetic, but residual stresses limit the quantitative analysis of the hermeticity. The microstructural studies confirm the bonds contain a single-phase intermetallic Cu6(Sn,In)5 that remains thermally stable up to 500 °C. This work shows Cu-Sn-In based low-temperature bonding method as a viable packaging option for optical MEMS or other temperature-sensitive components.

3D printing of customized lignocellulose nanofibril aerogels for efficient thermal insulation

Thermal insulation aerogel holds great promise in the transportation, storage, and use of temperature-sensitive electronic components under different environmental conditions. Due to their low density, high thermal stability, superior UV resistance, and low thermal conductivity, lignocellulose nanofibrils (LCNFs) aerogels meet the thermal insulation needs perfectly. However, the preparation of LCNFs aerogels with customizable size and high precision remains challenging. Herein, we report the following: (1) the preparation of LCNFs with tunable physicochemical properties from unbleached poplar pulp through the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation and ultrasonication approach, and (2) the 3D printing of customized thermal insulation materials using LCNFs as viscoelastic gelatinous inks. In addition to the chlorine-free bleaching merit, the LCNF inks exhibit much lower yield stress compared to cellulose nanofibrils (CNFs) inks, thereby facilitating the smooth extrusion of filament under a much lower printing pressure. Furthermore, the residual lignin endows LCNFs aerogels with superior moisture tolerance, mechanical protection, UV resistance, and thermal insulation performance for temperature sensitive electronic components such as chips and batteries. This work opens a promising avenue for the rapid manufacturing of customizable thermal insulation materials in a sustainable, cost-effective, and eco-friendly manner.

An Overview of Multilevel Inverters Lifetime Assessment for Grid-Connected Solar Photovoltaic Applications

Nowadays, due to advancements in power electronic devices as well as the rise in consumer awareness of the need to protect the environment on a global scale, many people are turning to the use of solar photovoltaic (PV) technology in the distributed power generation side. In the field of power electronics, manufacturers need to develop products that have high lifespans. Power electronic device reliability is important for the maintenance of the device and may be scheduled under that information. Rather than preventing failures, reliability can be improved by predicting them. Even though some research has been conducted over the past few years to investigate the reliability of power electronic devices, the reliability is many common circuits has not been investigated and this leads to a big challenge for researchers. In this review paper, an overview of the grid-connected multilevel inverters for PV systems with motivational factors, features, assessment parameters, topologies, modulation schemes of the multilevel inverter, and the selection process for specific applications are presented. In this paper, the findings of a comprehensive reliability analysis of fundamental multilevel inverters are studied. To evaluate the reliability of three basic multilevel inverters, a calculation is made using each component’s mean time before its failure. Two techniques of computation approximate and exact were used to arrive at the final result. To calculate power losses in temperature-sensitive components such as diodes and switches, MATLAB Simulink is employed. In addition, the concept of oversizing photovoltaic (PV) arrays is presented in this study. This concept proposes that energy output may be increased by increasing the size of the PV array under conditions of poor solar irradiation. Finally, the mission-profile-based and Monte Carlo simulation-based methods process flows are discussed for the accurate lifetime prediction and reliability assessments of PV inverters in a real-time scenario, followed by a conclusion with future work.

MICROELECTRONIC AUTOGENERATOR TEMPERATURE SENSORS

Microelectronic autogenerator temperature sensors based on transistor structures with differential negative resistance with primary parametric thermosensitive elements based on bipolar and field-effect transistors are proposed, moreover, primary parametric thermosensitive elements are active components of the circuits of parametric autogenerator temperature sensors, which greatly simplifies the design of the device. Based on the consideration of physical processes in primary parametric temperature-sensitive components and autogenerators of temperature sensors, mathematical models of autogenerator temperature sensors were developed, on the basis of which analytical expressions were obtained to determine the parametric dependences of sensitivity functions and transformation functions. It is shown that the main contribution to the conversion and sensitivity functions is made by a change in the ambient temperature, which causes a change in the equivalent capacitance and negative differential resistance of parametric autogenerator temperature sensors, which, accordingly, changes the output frequency of the device. The sensitivity of the sensor with a thermally sensitive bipolar transistor is from 11.25 kHz/°C to 21.5 kHz/°C, and the sensor with a thermally sensitive field-effect transistor is from 2.77 kHz /°C to 4.25 kHz/°C in the range of ambient temperature change 0 оС up to 100 оС. The obtained parametric dependences of the sensitivity and conversion functions show the possibility of easier calculation of the main characteristics of parametric autogenerator sensors, and also clearly demonstrate the influence of each component of parametric transducers and elements of parametric self-oscillating sensors on the output frequency of devices in comparison with the calculations of sensitivity and conversion functions from nonlinear equivalent circuits basis for solving the Kirchhoff equations.

Fiber Optic Voltage Sensor Based on Capacitance Current Measurement With Temperature and Wavelength Error Correction Capability

Traditional optical voltage transformers (OVTs) based on electro-optical and inverse piezoelectric effects are gradually exposing their accuracy and reliability issues. In contrast, fibers for measuring electricity have unique properties and significant advantages in the high-voltage power industry, especially fiber optic current sensor (FOCS), which has been widely used in the field of high-voltage measurement. As a result, a novel fiber optical voltage sensor (FOVS) is proposed, which uses FOCS to measure the current flowing through the capacitive voltage divider (CVD) and then calculates the primary voltage proportional to it. In order to solve the inherent temperature- and wavelength -dependent errors and achieve high accuracy, a novel closed-loop signal processing method, which aims to minimize the influence of temperature-sensitive components such as CVD, quarter waveplate, and sensing fiber on the measurement accuracy of the system, is presented. A 110-kV FOVS prototype with a rated voltage of 110/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$({3})^{1/2}$ </tex-math></inline-formula> kV and a rated frequency of 50 Hz is developed and tested. The results show that after temperature and wavelength correction, the accuracy reaches the metering class of 0.2% and protection class of 3P specified in GB/T20840.7-2007

Thermal control of temperature-sensitive electronic components using a vapor chamber integrated with a straight fins heat sink: An experimental investigation

Cooling temperature-sensitive appliances, such as electronic components, has recently become essential in their design and development to reduce the negative effect of excessive temperature rise on performance. The current experiment focuses on passive cooling of electronic devices utilizing an innovative vapor chamber with a cylindrical cross-section that is integrated with a straight fins heat sink. Therefore, a fabricated system is attached to an electric heater to imitate the heat dissipation from electronic devices. Several experiments are conducted to investigate the effect of two working fluids (Ethyl alcohol and water), seven varied charge ratios (ranging from 20% to 65%), different system orientations (ranging from 0° to 180° in 45° intervals), and seven distinct heat load values on overall system performance. The performance of the integrated vapor chamber-straight fins (VC-SF) heat sink is then compared to those of two conventional heat sinks, a straight fins (SF) heat sink and a solid copper plate (SCP) heat sink. The results reveal that using the integrated vapor chamber-straight fins (VC-SF) heat sink significantly reduces the average front wall temperature associated with the electronic component when compared to other heat sinks, and this effect holds true throughout all operating scenarios. Furthermore, when compared to other working fluids and charging ratios, the system filled with pure water as the working fluid and a charge ratio of 25% performs better for all operating conditions. Finally, at an inclination angle of 0°, the minimal hot wall temperature associated with the electronic component's operating temperature can be reached, resulting in the greatest performance. In contrast, the highest hot wall temperature is attained at an inclination angle of 180°, regardless of the applied heat load or charging ratio.

Influence of surface preheating and pretreatment on the adhesion of laser-melted PEEK to aluminum substrates

The high-performance polymer Polyether ether ketone (PEEK) is commonly used as friction-reducing coating in many areas of mechanical engineering. However, the coating of temperature-sensitive components is only possible to a limited extent due to the high hardness loss of the component during conventional oven processing at elevated temperatures to melt the PEEK layers. Alternatively, laser radiation can be used to melt the particulate PEEK layers and simultaneously reduce the thermal load on the substrate. A key challenge of these processes, however, lies in ensuring sufficient adhesion between the molten PEEK layer and the metal substrate. This study addresses the laser pretreatment of EN AW 6082 aluminum and investigates how the surface topography and preheating temperature of the substrate affect the adhesion behavior of the PEEK layer after laser-based melting as well as the hardness loss of the substrate during laser melting.

Ultrahigh efficient emulsification with drag-reducing liquid gating interfacial behavior

Emulsification is a crucial technique for mixing immiscible liquids into droplets in numerous areas ranging from food to medicine to chemical synthesis. Commercial emulsification methods are promising for high production, but suffer from high energy input. Here, we report a very simple and scalable emulsification method that employs the drag-reducing liquid gating structure to create a smooth liquid-liquid interface for the reduction of resistance and tunable generation of droplets with good uniformity. Theoretical modeling and experimental results demonstrate that our method exhibits ultrahigh efficiency, which can reach up to more than 4 orders of magnitude greater energy-saving compared to commercial methods. For temperature-sensitive biological components, such as enzymes, proteins, and bacteria, it can offer a comfortable environment to avoid exposure to high temperatures during emulsifying, and the interface also enables the suppression of fouling. This unique drag-reducing liquid gating interfacial emulsification mechanism promotes the efficiency of droplet generation and provides fresh insight into the innovation of emulsifications that can be applied in many fields, including the food industry, the daily chemical industry, biomedicine, material fabrication, the petrochemical industry, and beyond.

High-speed PMSM thermal analysis of totally enclosed fan cooled axial ventilation for centrifugal blower application

A temperature rise occurs when an electrical machine is fully loaded. The winding insulations of high-speed permanent magnet synchronous machines (PMSMs) are the most temperature-sensitive components, which can impact the machine’s longevity. Thus, recently, prediction for high-speed PMSM winding temperature has been given more and more attention. Thermal analysis by numerical (computational fluid dynamics (CFD) and finite element method (FEM)) and analytical lumped parameter thermal network (LPTN) methods have been widely used to estimate the temperature of totally enclosed fan cooled axial ventilation system (TEFCAVS) machines. Although numerical methods have more accuracy, their computation wastes time. Therefore, LPTN is being utilized in this paper due to the fastness of its computation. Firstly, estimated losses of high-speed PMSM with TEFCAVS via electromagnetic analysis, including copper, iron, permanent magnet (PM) eddy current, sleeve eddy current, and mechanical, are coupled to the LPTN model, which acts as heat sources for temperature prediction. Moreover, analysis shows that slot windings’ maximum temperature exceeds the winding insulation class with initial cooling configuration. Secondly, in order to mitigate slot winding temperature, the sensitivity study for liner conductivity, air gap’s heat transfer and lamination to housing’s contact is conducted by LPTN to identify which thermal parameter has more influence on mitigating the maximum temperature of the slot winding. Investigation shows that improving an air gap’s heat transfer has more influence than other parameters for mitigating slot winding maximum temperature below its insulation class. Lastly, the machine is designed and tested with the best thermal-sensitive parameters. Then test results for the maximum temperature of the winding are compared with estimated results to ensure the proposed LPTN correctness, and the calibration process confirms LPTN accuracy.

Numerical investigation of thermomechanical response of multiscale porous Ultra-High Temperature Ceramics

Recent advances in Ultra-High Temperature Ceramics (UHTC) manufacturing have permitted the development of multiscale porous UHTC microstructures. Within the target application of hypersonic vehicles, dense UHTCs are suitable for thermal protection on leading edges, whereas porous UHTCs may find a role in providing thermally insulated interfaces for temperature-sensitive interior components. Designing vehicles incorporating porous UHTCs requires a characterization of their thermomechanical properties across the full range of expected operating temperatures spanning −20 °C–2500 °C. This work represents a preliminary study in performing this characterization. Several numerical experiments are performed using a coupled thermomechanical implementation of the Material Point Method to determine the temperature dependence of effective material properties both with and without damage. Furthermore, complex time-dependent boundary conditions derived from known hypersonic flight profiles are simulated in order to probe the various couplings between deformation, damage and heat transfer. It is shown that the model reveals the importance of micro-buckling in determining effective material stiffness and thermal conductivity.

Temperature Correction and Result Evaluation of Lunar Mineralogical Spectrometer for Chang’E-5 Mission

The lunar mineralogical spectrometer (LMS) is the primary scientific payload of the Chang’E-5 mission of the China Lunar Exploration Program. The LMS is responsible for the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ</i> spectral detection and analysis of the sampling areas of interest on the Moon’s surface. The LMS needs to adapt to a wide range of temperature conditions, varying between the lunar morning to noon, based on the time, location, and work process of the LMS. Thus, ensuring consistency in the spectral data obtained at high temperatures and a wide range of operating environments is a major challenge. In this study, a thermal analysis model of the LMS is built, and the temperature variation of the LMS during its operation on the lunar surface is simulated using the instrument workflow that is based on the simulation results. Independent experiments were also carried out for the temperature-sensitive components in the LMS, and subsequently, the temperature correction model and model coefficients for each temperature-sensitive component were obtained. The final correction result was a quantitative assessment of the ground test data and the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ</i> lunar detection data. For the ground tests at different temperatures, the average errors were found to be 0.57% and 1.2% for the short- and medium-wave data, respectively, after applying the temperature correction. When the LMS was operating on the lunar surface, the average errors for the short- and medium-ware data after the temperature correction were calculated to be 0.59% and 0.8%, respectively.

Poster session

The Nightingale Hospital North West (NHNW) was a temporary field Hospital, built and run in collaboration between the NHS and the military. The Hospital was assembled in record time to combat the additional pressures placed on the NHS during the COVID-19 global pandemic. Due to the distance of the NHNW from Oxford Road Campus (ORC), the Transfusion service was asked to supply on-site O D Negative red cells for emergency blood provision on the 8th of April 2020. We needed a quick, creative and safe way to bring the blood closer to the patients. After seeing the already successful collaboration between the NHS and the military, it was decided what better way to support the war on COVID-19, but to respond as the military would. This solution came in the form of Golden HourTM Technology, Credo Cube;this technology was originally designed for the military to protect temperature sensitive components in the battlefield. Validation was carried out in a staggered approach to ensure a Credo Cube was on site as soon as possible. Each Credo Cube was validated for up to 120 hours. Variations on user preparation, packaging and stability meant we decided to adopt a 72 hour change over with the NHNW to fit in with our current workload. Continuous temperature monitoring was achieved by utilising small microchip temperature devices, to aid early detection of any problems and protect the quality of the emergency units issued. Each Credo Cube was truly-'Emergency Blood Provision in a Box'. The Cube contained giving sets and all documentation and information for the NHNW staff, including guidance on transfusion, traceability, transfer and investigation of transfusion reactions. The blood was on site by the 20th of April 2020, this was an extremely short time frame and a true collaboration between Wythenshawe Hospital and Oxford Road Campus. Our success was measured by the availability of emergency units to the NHNW patients, safeguarding against a Major Haemorrhage and supporting transfer of the critical patients back to A&E. This gave our users re-assurance that all patients within our care had the safest blood available for their needs.

10‐2: Study of an Ultra‐fast Photonic Soldering Technology without Thermal Damage in Display Module Package

An ultra‐fast photonic soldering approach to be introduced in the display module package, which has great advantages in soldering low temperature and heat sensitive components, was demonstrated. The soldering and heat conduction process was verified. As a result, flexible substrate was successfully interconnected on the display panel by photonic soldering.

Dual-responsive graphene hybrid structural color hydrogels as visually electrical skins

Stimuli-responsive materials have been experiencing explosive developments, which are functionally integrated with multi-signals in response to external environment variations. Here, we present a novel dual-responsive graphene hybrid structural color film as electronic skins. The film is fabricated by adding conductive reduced graphene oxide (rGO)-poly(N-isopropylacrylamide) (PNIPAM) filler into a poly(ethyleneglycol) diacrylate (PEGDA) inverse opal scaffold. The inverse opal scaffold imparts the film with brilliant structural color and the addition of rGO endows the hybrid film with excellent conductivity. Because of the temperature response adjustability of the PNIPAM polymer, the resultant film is capable of changing volume or internal nanostructure under temperature stimuli. In addition, benefiting from the extraordinary near-infrared (NIR) photo-thermal transformation property of rGO, such hybrid films with temperature-sensitive polymer components could be introduced with photo-responsive properties. Based on these features, the hybrid film could not only feed electrical signals back, but also exhibit color changes visually when responding to the temperature and NIR stimuli. Furthermore, the value of the hybrid film on electro-thermal conversions has been explored. These features indicate that the hybrid conductive structural color films possess the promising application prospects in flexible electronics.

Modification of Silver Nanowire Coatings with Intense Pulsed Ion Beam for Transparent Heaters.

In this report, an improvement of the electrical performance and stability of a silver nanowire (AgNW) transparent conductive coating (TCC) is presented. The TCC stability against oxidation is achieved by coating the AgNWs with a polyvinyl alcohol (PVA) layer. As a result, a UV/ozone treatment has not affected the morphology of the AgNWs network and the PVA protection layer, unlike non-passivated TCC, which showed severe degradation. The irradiation with an intense pulsed ion beam (IPIB) of 200 ns duration and a current density of 30 A/cm2 is used to increase the conductivity of the AgNWs network without degradation of the temperature-resistant PVA coating and decrease in the TCC transparency. Simulations have shown that, although the sample temperature reaches high values, the ultra-high heating and cooling rates, together with local annealing, enable the delicate thermal processing. The developed coatings and irradiation strategies are used to prepare and enhance the performance of AgNW-based transparent heaters. A single irradiation pulse increases the operating temperature of the transparent heater from 92 to 160 °C at a technologically relevant voltage of 12 V. The proposed technique shows a great promise in super-fast, low-temperature annealing of devices with temperature-sensitive components.

Direct ink writing of polycaprolactone / polyethylene oxide based 3D constructs

There has been increasing interest over recent years in the application of three-dimensional (3D) printing technologies in the biomedical field. One such method is Direct Ink Writing (DIW); this approach has the potential advantage of allowing room-temperature deposition of materials, presented as an ink, to build complex architectures. DIW offers the ability to process biomaterials containing temperature-sensitive components. Due to the fabrication principles of DIW, there are specific rheological requirements that the ink must exhibit for the 3D construction. For this reason, hydrogel-based liquid feed stocks have been the focal point of ink development. As a consequence, studies based on inks comprising hydrophobic biomaterials, which are insoluble in water and hence unsuited to the hydrogel approach, have been limited.In this study, we investigate novel inks that utilize polycaprolactone (PCL), a hydrophobic polymer, as the primary constituent by dissolving the polymer in solvent systems based on dichloromethane (DCM) and acetone (ACE). Moreover, polyethylene oxide (PEO) was incorporated into the PCL systems in order to extend the range of hydrophilicity of the systems. The rheological properties of the inks were investigated as a function of polymer composition and solvent system. Woodpile constructs of PCL and PCL/PEO were fabricated using DIW method and were assessed by a series of material characterisation. The type of solvent system had a noticeable impact on the ink rheology, which ultimately affected the surface properties. The incorporation of PEO particularly enhanced the roughness and wettability of the constructs. Our results support the use of DIW as a new means to process hydrophobic polymers for biomedical applications.

Effect of Temperature on Electromagnetic Performance of Active Phased Array Antenna

Active phased array antennas (APAAs) can suffer from the effects of harsh thermal environments, which are caused by the large quantity of power generated by densely packed T/R modules and external thermal impacts. The situation may be worse in the case of limited room and severe thermal loads, due to heat radiation and a low temperature sink. The temperature field of the antenna can be changed. Since large numbers of temperature-sensitive electronic components exist in T/R modules, excitation current output can be significantly affected and the electromagnetic performance of APAAs can be seriously degraded. However, due to a lack of quantitative analysis, it is difficult to directly estimate the effect of temperature on the electromagnetic performance of APAAs. Therefore, this study investigated the electromagnetic performance of APAAs as affected by two key factors—the uniformly distributed temperature field and the temperature gradient field—based on different antenna shapes and sizes, to provide theoretical guidance for their thermal design.

Organic fragments newly released from heat-treated peat soils create synergies with dissolved organic carbon to enhance Cr(VI) removal.

Surface fires occur naturally or anthropogenically and can raise the temperature at the soil surface up to 600°C. The heat derived from the surface fire can be subsequently transferred into CO2-enriched subsoils. As a result, the chemical compositions of soil organic matter (SOM) may be altered in fire-impacted anaerobic environments, indirectly influencing the redox transformations of pollutants, such as Cr(VI). In this study, a peat soil was heated up to 600°C with limited air flow to simulate the effects of heat on the SOM during surface fire events. Then, Cr(VI) removal, including reduction and sorption, by the heat-treated peat soils was determined in relation to changes in the soil organic components. The results showed that the amount of O-containing functional groups, -CH2/-CH3 units of aliphatic groups, and dissolved organic carbon (DOC) in the SOM gradually decreased with an increase in the heating temperature. The removal of 0.1932mM Cr(VI) did not exhibit a consistent decline along with the changes in these soil components. The heating temperatures of 200 and 250°C were the thresholds that led to the decomposition of temperature-sensitive soil organic components such as lignin and other labile SOM. Such newly released organic fragments synergized lignin-like substances and carboxyl groups, resulting in up to 99% removal of the initially added Cr(VI). As the heating temperatures were increased from 300 to 600°C, Cr(VI) reduction decreased from 66% to 20%. The black carbon-like materials and/or aromatic-containing moieties were the major components responsible for Cr(VI) reduction in 600°C-treated peat soils.