Thermal Compression Research Articles

Box–Behnken experimental design for optimization of chitosan foam materials reinforced with cellulose and zeolite

AbstractFoam materials produced from biopolymers stand out as a more environmentally friendly insulation material solution. This study presents a comprehensive investigation into the development and optimization of chitosan‐based foam materials using a Box–Behnken design. The foams were engineered using varying proportions of chitosan (0.5–3%), cellulose (0.5–3%), and zeolite (0.5–3%), targeting their application as thermal insulators. The physical and thermal properties of the foams that were produced were affected by the type and ratios of components, with density and thermal conductivity ranging from 0.0853 to 0.1915 g cm−3 and 0.0324 to 0.0921 W mK−1, respectively. Higher chitosan content improved insulation properties and mechanical strength whereas zeolite increments increased density and thermal conductivity. Using statistical analysis through the Box–Behnken design, we optimized the foam formulations, achieving minimum thermal conductivity and maximum compression strength at an averaged density, suggesting a strong potential for environmental sustainability applications. The recommended optimal chitosan:cellulose:zeolite composition ratio of 3:3:0.88 provides a valuable insight for tailored foam material formulation. This study shows the relationships between the composition of a composite material and its resultant properties, optimizing its preparation for industrial applicability in an environmentally conscious way within the context of insulation and construction. This investigation contributes to the field of material science by highlighting the versatility and potential of biopolymers but also aligns with the increasing need for green building materials.

Applications of Geothermal Energy for Desalination: A Review Technological Advancement and Water Security

Geothermal energy, harnessed through the Earth's thermal resources, emerges as an enduring and sustainable remedy to tackle the urgent concern of water scarcity through desalination. By harnessing the innate thermal reservoirs within the planet, geothermal energy provides a distinctive avenue for generating heat and electricity, particularly when synergistically aligned with desalination procedures. To understand the insights of the implications of geothermal energy for desalination, we conducted a comprehensive literature review analysis. Main objectives of the review are to (i.) disseminate insights into geothermal-driven desalination, (ii.) explore potentialities and obstacles of geothermal-driven desalination, and (iii.) evaluate forthcoming environmental, socio-economic predicaments associated with this approach. We selected 50 peer reviewed scholarly communications published using Google Scholar from 2000 to 2022, focusing on impactful English-language publications within esteemed scientific journals. We found multi-effect evaporation/distillation (MED); multi-stage flash distillation (MSF); thermal vapor compression (TVC) and mechanical vapor compression (MVC). Membrane processes include electrodialysis (ED), reverse osmosis (RO), and membrane desalination are the common techniques used across mainly in Australia, USA, UAE, Sub-Saharan and African nations, and Japan. The integration of innovative designs of these methods can enhance the efficacy and cost-efficiency of geothermal desalination systems. Furthermore, critical environmental, social, and economic concerns linked to geothermal-driven desalination were identified. We noted that high-capacity factor for stable heat supply, independent of seasonal changes, ideal temperatures (70-90° C) for low-temperature desalination, cost-effectiveness with simultaneous power and water production, environmentally friendly with no emissions, versatile to meet energy demand across scales are some of main advantages of selection of geothermal energy for desalination. Some studies showed that geothermal energy for desalination is practical and effective, especially in areas facing water scarcity, strengthening water security. However, challenges persist, necessitating inventive solutions encompassing the pursuit of robust materials designed for high-temperature operation and streamlining energy conversion and integration processes. Other foreseen difficulties include the potential environmental impacts on geothermal reservoirs and the necessity for careful resource management to maintain a fair socio-economic equilibrium. Thus, the future research direction should be mainly focus on harnessing geothermal heat to drive the process, significantly reducing energy consumption and mitigating carbon emissions to potentially be employed across the world.
 
 Keywords: Carbon emission mitigation, Desalination, Energy conservation, Geothermal Energy, Water security

Study on Hot Deformation Behavior and Processing Maps of Cobalt‐Based Superalloy GH5188

True stress–strain data are obtained through the thermal compression test of the cobalt‐based superalloy GH5188 at the temperature range of 1080–1180 °C and the strain rate of 0.1–10 s−1, and the Arrhenius constitutive equation considering the effects of temperature, strain rate, and strain is established. The microscopic deformation mechanism and the appropriate process range are proposed based on the analysis of the dynamic material model and electron backscattered diffraction (EBSD). The results show that the established constitutive equation exhibits predictive ability, and the calculated thermal activation energy Q value is 446.1054 KJ mol−1; when the strain is 0.7, the GH5188 superalloy undergoes dynamic recrystallization (DRX) at 1130 °C in the form of discontinuous DRX; when the temperature is 1180 °C, the degree of DRX is significantly improved, and evenly distributed equiaxed grains are obtained; when the strain is 0.2, 0.4, and 0.6, DRX is mainly affected by the degree of deformation, and its occurrence is accompanied by the generation of Σ3. Combined with the analysis of the processing maps and EBSD diagrams, the optimal thermal deformation parameters of GH5188 alloy are determined as follows: the strain is 0.7, the deformation temperature is about 1180 °C, and the strain rate is about 1 s−1.

Theoretical performance assessment of a multi-effect distillation system integrated with thermal vapour compression unit running on solar energy

Abstract Mathematical models can be successfully applied to predict the multi-effect distillation system integrated with thermal vapour compression unit (MED-TVC) performance under different operating conditions. In this work, a one-dimensional (1-D) mathematical model was developed to perform the theoretical analysis of a small-scale parallel feed MED-TVC desalination system driven by solar heat. A parametric study was conducted allowing the ejector motive steam temperature, first effect temperature, between effects temperature difference and ejector compression ratio to vary within an expectable range. The results showed that higher motive steam temperatures, had a positive impact on the water yield up to an optimal point. Any additional increase of driving steam temperature reduced water yield. Gain output ratio ($GOR$) was maximum at the highest considered motive temperature. It was found that the calculated specific heat transfer area does not depend on the motive temperature variation. Water yield, $GOR$ and specific heat transfer area decrease with the ejector compression ratio. The temperature difference between the evaporator effects had no effect on the water yield and $GOR$. It only decreases the specific heat transfer area. First effect temperature should be as low as possible with respect to operational constraints. Based on the parametric study, the optimal design operating conditions, corresponding to the maximum water yield is identified for a small-scale three-effect desalination system. The unit can produce up to 204 l/h drinking water with a gain output ratio of 8.6 and specific heat transfer area of 575 m2/kg/s using about 22 kW of solar heat.

Thermal deformation behavior investigation of Ti–10V–5Al-2.5fe-0.1B titanium alloy based on phenomenological constitutive models and a machine learning method

The two-phase titanium alloy Ti–10 V–5Al-2.5Fe-0.1 B was taken as the experimental material, and thermal compression experiments were carried out at a deformation temperature of 770–920 °C and a strain rate of 0.0005–0.5 s−1. An Arrhenius model, a modified Johnson-Cook model, and an improved BP neural network model based on the sparrow search algorithm (SSA-BP) model were established to predict the high temperature rheological stress of the alloy. A comparison of the prediction accuracy of the three models was made. When the partial random data in the rheological curves was used for model building and relatively independent data were used for predicting the rheological stress, the SSA-BP model had higher prediction accuracy, which exhibits the highest mean square correlation coefficient (R2) value of 0.9992 and the lowest root mean square error (RMSE) and average absolute relative error (AARE) values of 1.3031, and 2.0947 %, respectively. The ability of three models to predict the rheological stress for the new process parameters was verified. Results show that the SSA-BP model still has better prediction ability, which exhibits the highest mean square correlation coefficient (R2) value of 0.9720 and the lowest root mean square error (RMSE) and average absolute relative error (AARE) values of 5.0099, and 6.0382 %, respectively. The predicted values of SSA-BP for the rheological stress were used to construct the hot processing map. Results show that the trend of the power dissipation factor (η) value from the hot processing map predicted by SSA-BP can well agree with the microstructure evolution of the alloy.

Investigation on combining multi-effect distillation and double-effect absorption refrigeration cycle to recover exhaust heat of SOFC-GT system

This study introduces the double-effect absorption refrigeration cycle (D-ARC) and multi-effect distillation with thermal vapor compression unit (MED-TVC) technologies to recover exhaust heat from the SOFC-GT system. This scheme can efficiently utilize waste heat at various temperature levels while enabling large-capacity cooling and freshwater production. The supercritical CO2 Brayton cycle is employed to facilitate the reliable operation of D-ARC and MED-TVC within their preferred temperature zones while enhancing the power output of the entire system. The techno-economic-environmental evaluation, comparative analysis and sensitivity analysis are performed to explore the feasibility of its engineering implementation. The proposed system obtains thermal, exergic and electrical efficiencies of 78.56 %, 65.41 % and 65.77 % with the total cost rate being 18.53 $/h and freshwater production 829.30 ton/year under design conditions, respectively. Exergy analysis indicates that SOFC and afterburner exhibit the highest irreversibility with values of 21.60 kW and 26.02 kW among all the components. Comparative analysis reveals that the system has exceptional thermal efficiency while exhibiting competitive advantages in electrical and exergic efficiencies compared to similar systems. Sensitivity analysis demonstrates that the electrical efficiency and net power output stabilize at their respective maximum values within the SOFC inlet temperature range of 514.3℃-528.6℃. Moreover, it is a promising option by increasing SOFC operating pressure and GT isentropic efficiency to enhance system efficiency and reduce CO2 emission. This work contributes to the development and waste heat recovery of the SOFC-GT system and other prime power units with similar exhaust gas temperature levels.

Anisotropic thermo-mechanical response of layered hexagonal boron nitride and black phosphorus: application as a simultaneous pressure and temperature sensor.

Hexagonal boron nitride (hBN) and black phosphorus (bP) are crystalline materials that can be seen as ordered stackings of two-dimensional layers, which lead to outstanding anisotropic physical properties. Knowledge of the thermal equations of state of hBN and bP is of great interest in the field of 2D materials for a better understanding of their anisotropic thermo-mechanical properties and exfoliation mechanism towards the preparation of important single-layer materials like hexagonal boron nitride nanosheets and phosphorene. Despite several theoretical and experimental studies, important uncertainties remain in the determination of the thermoelastic parameters of hBN and bP. Here, we report accurate thermal expansion and compressibility measurements along the individual crystallographic axes, using in situ high-temperature and high-pressure high-resolution synchrotron X-ray diffraction. In particular, we have quantitatively determined the subtle variations of the in-plane and volumetric thermal expansion coefficients and compressibility parameters by subjecting these materials to hydrostatic conditions and by collecting a large number of data points in small pressure and temperature increments. In addition, based on the anisotropic behavior of bP, we propose the use of this material as a sensor for the simultaneous determination of pressure and temperature in the range of 0-5 GPa and 298-1700 K, respectively.

Highly oriented BN-based TIMs with high through-plane thermal conductivity and low compression modulus.

In the pursuit of effective thermal management for electronic devices, it is crucial to develop insulation thermal interface materials (TIMs) that exhibit exceptional through-plane thermal conductivity, low thermal resistance, and minimal compression modulus. Boron nitride (BN), given its outstanding thermal conduction and insulation properties, has garnered significant attention as a potential material for this purpose. However, previously reported BN-based composites have consistently demonstrated through-plane thermal conductivity below 10 W m-1 K-1 and high compression modulus, whilst also presenting challenges in terms of mass production. In this study, low molecular weight polydimethylsiloxane (PDMS) and large-size BN were utilized as the foundational materials. Utilizing a rolling-curing integrated apparatus, we successfully accomplished the continuous preparation of large-sized, high-adhesion BN films. Subsequent implementation of stacking, cold pressing, and vertical cutting techniques enabled the attainment of a remarkable BN-based TIM, characterized by an unprecedented through-plane thermal conductivity of up to 12.11 W m-1 K-1, remarkably low compression modulus (55 kPa), and total effective thermal resistance (0.16 °C in2 W-1, 50 Psi). During the TIMs performance evaluation, our TIMs demonstrated superior heat dissipation capabilities compared with commercial TIMs. At a heating power density of 40 W cm-2, the steady-state temperature of the ceramic heating element was found to be 7 °C lower than that of the commercial TIMs. This pioneering feat not only contributes valuable technical insights for the development of high-performance insulating TIMs but also establishes a solid foundation for widespread implementation in thermal management applications across a range of electronic devices.

Hot processing map and high temperature deformation behaviour of TB17 Ti alloy

The thermal compression experiments of TB17 titanium alloy under different thermal deformation process parameters were carried out using a thermal simulation compressor. The high-temperature plastic flow behaviour of the alloy was studied. It was found that with the decrease of the deforming temperature and the increase of the strain rate, the flow stress increased, and the discontinuous yield phenomenon occurred in hot deformation. The larger the strain rate, the more obvious the discontinuous yield phenomenon. The thermal activation energy Q decreased with the increase of strain, and the average value of activation energy Q is 209.54 KJ / mol. The constitutive equation of high-temperature plastic flow of TB17 titanium alloy was established. The predicted values of this equation are in good agreement with the experimental values. The average error is 3.987 %, and the correlation coefficient is 0.9972, which has high accuracy. Based on the Prasad criterion, the hot processing map of TB17 titanium alloy was constructed. It was found that the flow instability zone was mainly concentrated in the high strain rate region. The flow instability zone was determined to be 795 °C ~ 895 °C, 0.046s-1 ~ 1s-1, and the stable deformation zone was mainly located in the region with high temperature and low strain rate. The optimum processing parameter range is 860 °C ~ 895 °C, 0.001 s-1 ~ 0.025 s-1.

Ultralow-cost piezoelectric sensor constructed by thermal compression bonding for long-term biomechanical signal monitoring in chronic mental disorders.

Wearable bioelectronic devices, which circumvent issues related to the large size and high cost of clinical equipment, have emerged as powerful tools for the auxiliary diagnosis and long-term monitoring of chronic psychiatric diseases. Current devices often integrate multiple intricate and expensive devices to ensure accurate diagnosis. However, their high cost and complexity hinder widespread clinical application and long-term user compliance. Herein, we developed an ultralow-cost poly(vinylidene fluoride)/zinc oxide nanofiber film-based piezoelectric sensor in a thermal compression bonding process. Our piezoelectric sensor exhibits remarkable sensitivity (13.4 mV N-1), rapid response (8 ms), and exceptional stability over 2000 compression/release cycles, all at a negligibly low fabrication cost. We demonstrate that pulse wave, blink, and speech signals can be acquired by the sensor, proposing a single biomechanical modality to monitor multiple physiological traits associated with bipolar disorder. This ultralow-cost and mass-producible piezoelectric sensor paves the way for extensive long-term monitoring and immediate feedback for bipolar disorder management.

Relaxation temperature and storage stability of the functionalized cell wall material residue from lemon peel

Lemon peel cell wall material (CWM) residue obtained after acid pectin extraction can be functionalized into a texturizing ingredient using mechanical treatments such as high-pressure homogenization. The application of CWM as a texturizing ingredient is most likely through a dry powder and thus the stability of its functionality (rheological property) during storage becomes an obvious question. However, studies on the glass transition properties of this CWM residue and it's relation to storage stability are largely lacking. This study aims to first evaluate the potential of two methods, i.e. DSC analysis and combined TMCT-DMTA (thermal mechanical compression test – dynamic mechanical thermal analysis) to measure the Tg and relaxation temperature of lemon peel CWM and subsequently relate the results to the stability of the material's rheological property. The results showed that DSC-based Tg measurements may not be the most appropriate indicator for storage stability of the lemon peel CWM residue, despite being the most commonly used method to explain state transition in materials. On the other hand, the structural relaxation phenomena elucidated by the change in mechanical properties measured by TMCT-DMTA correlated with the results of storage stability of the material. To ensure the stability of the CWM residue, storage should be carried out at conditions (temperature and moisture content) before the onset of tan δ curve change. In conclusion, relaxation phenomena observed through the measurement of mechanical properties, in particular the tan δ curve from DMTA, provides a suitable starting point for inferring the stability of the functionalized CWM residue.

Hot Compression of Calcium Chloride and Sodium Carbonate Modifies Wood for Tsoongiodendron odorum

To enhance the density and properties of Tsoongiodendron odorum and expand its range of applications, the physical and mechanical characteristics, such as density and hardness, were investigated after impregnating a solution of sodium carbonate and calcium chloride to generate calcium carbonate filler within the wood, followed by thermal compression. The results showed that the surface density of wood was significantly increased by 86.4%. The rate of weight gain gradually increased with sodium carbonate concentration, reaching a maximum of 55.67%. Hardness increased by 85.3%. The optimal treatment process is a compression rate of 5%, a pressing temperature of 170 °C, and a hot-pressing time of 30 min. Microscopic observations revealed that the calcium carbonate was predominantly distributed on the surfaces of wood, while the surface cells exhibited deformation upon compression. Conversely, the cells in the innermost region of the wood remained largely unaltered, thereby achieving a stratified compression effect. Impregnation and compression treatment increases the hardness and bending strength of Tsoongiodendron odorum, but spring-back may occur, and the dimensional stability measures necessitate further investigation and analysis.

Hydrogen refueling station synergistically driven by liquid hydrogen pump and thermal compression

The energy consumption of conventional 70-MPa hydrogen refueling stations (HRS) with liquid hydrogen (LH2) pumps remains at a high level due to the low efficiency of LH2 pumps working at extremely high pressures, up to nearly 90 MPa. This paper presents a novel HRS with significantly lower energy consumption, based on a step-by-step compression strategy enabled by a highly-efficient 50-MPa LH2 pump for low-pressure compression and a subsequent thermal compression module for high-pressure compression driven by thermal energy. The performance of the cryogenic pressure vessels in the HRS process is analyzed via a numerical model, and then several improvements to the HRS process are proposed for large-scale refueling requirements. Finally, the techno-economic performance of the HRS is compared with the conventional HRSs and the HRS with pure thermal compression. Compared to the conventional HRSs with 90-MPa LH2 pumps, the capital cost of the proposed 400-kg/day HRS is reduced to $1.52M from $1.80M, while its energy consumption is reduced to 0.3 kWh/kgH2 from 1.3 kWh/kgH2. This work provides a new solution for low-energy-consumption hydrogen refueling which would be beneficial for reducing the overall cost of the hydrogen supply chain.

Study of the effect of dual-phase transformation on the processing map of Al0.9FeCoNiCr high-entropy alloys under peak stress conditions

ABSTRACT Single-pass thermal compression simulation experiments were performed on a dual-phase Al0.9FeCoNiCr high-entropy alloy at strain rates of 1–0.001 s−1, temperatures of 850–1050°C (true strain of 0.916). According to a model of the dynamic DMM processing map proposed by Prasad et al, the hot-deformation behaviour of the alloy was analysed. The flow-instability regions were obtained as follows: temperature 850–1040°C with a strain rate 1–0.1 s−1 and 850–900°C with a strain rate of 1–0.001 s−1. The microstructure was obtained by EBSD characterisation. It was found that under certain strain-rate conditions, the FCC phase in the dual-phase Al0.9FeCoNiCr high-entropy alloy did not change significantly at low temperatures but increased significantly when the temperature was over 1000°C. The hot-working properties of the alloy are affected when the FCC phase exceeds 80%.

Nanoporous Cu-Sn Intermetallic Material for Interconnects in Electronic Packaging

Nanostructured and nanoparticulate Cu-based materialshave emerged as viable replacements of conventional solder materials for realizing high-performing and reliable interconnection in today's 2.5D/3D electronic packaging. Unlike the traditional interconnects, those materials offer better compliance during the overall packaging routines. Owing to their highly developed surface area resulting of their uniform interconnected porosity, said nanomaterials also enable joint formation by sintering by thermal compression realized at high pressure and at much lower temperatures compared to bulk counterparts. Recently, sintering of nanoporous (np) Cu was demonstrated under high pressure and temperature after initial pre-treatment in acid for surface oxide removal. Separately, other studies have been focused on the attachment of Cu pillars to pads by using nanoparticulate Cu pastes as sintering material. The ultimate goal is to develop materials that facilitate a highly effective and durable chip-to-substrate interconnection.In this report, we discuss the development and use of nanoporous uniform and continuous CuSn films for low-temperature joint formation. The novelty of this work is realized through the introduction of tin (Sn) to work along with the np-Cu structure for ensuring lower sintering temperatures with a goal of producing packaging interconnects based on CuSn intermetallic compound (IMC). The addition of Sn to the np-Cu system is performed using a bottom-up, all-electrochemical synthetic approach (see Figure 1). The method is founded on the initial synthesis of thin films of np-Cu by dealloying of Cu-Zn alloys, followed by a conformal coating with a thin layer of Sn. The main goal of the proposed approach is to form a np-CuSn composite that upon sintering at high temperature and pressure, transitions into a densely compressed Cu3Sn IMC bonding material. Realized accordingly as interconnect layer, said material ensures good stability at high current densities (greater than 1×105 A ⋅ cm2 ) and low electrical resistivity (equal or less than 8.5 µΩ ⋅ cm).The synthetic details and then the applicability of the Cu-Sn nanomaterials obtained using the approach for synthesis of a low-temperature joint formation material are also discussed. The Sn-coating process was administered by galvanic pulse plating, which was optimized to provide a conformal Sn coating and thus, to retain the initial np-Cu overall porous structure. Another optimization effort was made for ensuring a Sn atomic fraction that allows for the formation of Cu6Sn5 IMC. After the optimization process for determining the necessary plating conditions for reaching mostly Cu6Sn5 composition ratio, the material was subjected to sintering at temperatures in the range from 300ºC to 200oC, and at a pressure of 20 MPa. We found that the joints formed were heavily densified and consisted mainly of Cu3Sn IMC. The report presents the new approach as a facile and cost-effective method for synthesizing nanostructured Cu-Sn films as viable candidates for a new-generation of interconnect materials together with the demonstration of assembly processes that optimize robustness and reliability. The discussion also shows the proposed approach’s applicability by realization of low-temperature sintering of nanostructured CuSn films in pre-designed fine pitch assemblies. Figure 1: Schematic representation demonstrating key steps of the approach for synthesis of np-CuSn composites. Figure 1

(Invited) Direct Bonding and Its Interface for High-Density Integration of Superconducting Qubits

Superconducting qubits are one of the intensive approaches to fabricate quantum computing (QC). Qubits can be manufactured by the current Si-based semiconductor manufacturing processes. However, circuits should be superconducting material such as Nb (Tc=9.29 K), Al (Tc=1.18 K), Pb (Tc=7.2 K), In (Tc=3.4 K) , etc. In current technology, qubits are arranged in planar geometry in a chip, and each qubit should wire to control and read signal lines in the same plane. When a large number of qubits are integrated, these wires would be too constrained, and several problems would be actualized, such as wiring for qubits located at the chip center, crosstalk among wiring, and so on. The signal integrity for the QC devices is much better to have qubits at short distances from the control circuitry. Therefore, 3D wiring is required for a large-scale qubit integration. 3D integration of qubits with interposer chips by flip-chip bonding is the proof-of-concept of the large-scale qubit integration. The 3D integration approaches for qubit- based devices are the same as conventional electronic devices, including the through silicon via (TSV) process for interposers and micro bump flip-chip bonding. However, they use superconducting metals instead of copper and other non-superconducting materials. Most flip-chip microbump bonding processes require thermal compression at over 170 °C. Superconducting elements are easily degraded by heat. Consequently, we apply surface activated bonding (SAB) to a superconducting metal as a low-temperature bonding process for superconducting circuits.The test element group (TEG) for the current-voltage (I-V) measurement of the bonded interface was bonded by SAB method, and at the Nb SAB interface layer is a 2- to 3-nm-thick amorphous layer and the layer consist of Si-rich interfacial layer compared to the Nb bulk area. The bonding specimens were activated on jigs made of Si during the bonding process; then the Si sputtered by FAB was redeposited on the bonding surfaces. Furthermore, the bonded specimen was wired using Al wire to a chip carrier with a stage installed into a 0.3-K cryostat. As a result, the Tc of this path is 9.3 K, which is very similar to that of Nb bulk (9.2 K). However, a small step of the Tc at 9.1-9.4 K was also observed. (Fig.1) [1]In this study, we discuss the superconducting interface of direct bonded Nb-Nb by Tc, and also the interfacial structure measured by polarized neutron reflectometry (PNR). The results show clear spin asymmetry in the superconducting state, as splitting is observed in the fringes of the parallel neutron (neutron spins parallel to the external magnetic field 0.1 T) reflection R+ and the antiparallel (neutron spins antiparallel to it) reflection R−, where the latter has become larger. This well-known effect is related to the flux penetration in the superconducting state. Therefore, unique information about the superconducting state of the buried thin film can be measured by using the polarized neutron beam. For this project the major advantage of PNR will be to characterize the superconducting state at the deeply buried Nb interfaces, sandwiched between the two substrate wafers, which would be infeasible using alternate techniques.[1] M. Fujino, et. al., J. Appl. Phys., 133, 015301, 2023 Figure 1

Artificial dermis combined with split-thickness skin autograft in the treatment of hand thermal compression wounds: a single center case-control study.

To explore the clinical effect of artificial dermis combined with split-thickness skin autograft in treating hand thermal compression wounds. Forty-two patients in our hospital from January 2016 to October 2022 with thermal compression wounds were divided into two groups. The survival rate of autologous skin grafts seven days after skin grafting, the number of operations, total hospital stay, total hospitalization cost, and bacterial culture results of secretions were recorded. The visual analog scale was used to evaluate the wound pain. The condition of skin graft rupture was recorded and the scar status of the donor site was evaluated by the Vancouver Scar Scale. It showed combination of artificial dermis, split-thickness skin autograft, and vacuum sealing drainage improves the treatment of hand thermal compression wounds by enhancing the survival rate of skin grafting (95.24% > 66.67%), reducing the number of operations (P < 0.001), relieving wound pain (P < 0.001), effectively controlling wound infection (4.76% < 9.52%), and reducing the skin graft rupture rate after surgery (4.8% < 28.6%). There was no evident scar hyperplasia in the donor (P = 0.003) and skin graft areas (P < 0.001), which had a good recovery of hand function (P = 0.037); however, this treatment strategy may prolong the hospital stay (P = 0.030) and increase the total hospitalization cost (P = 0.030). The composite transplantation of artificial dermis and split-thickness skin combined with the VSD significantly improves treatment and aesthetic outcomes in patients with thermal compression wounds to the hand, which is worth promoting and applying in clinical practice.

Addition of ceramic waste for the preparation of VA-based alkali-activated material with high temperature resistance

This study prepares volcanic ash (VA)-blast furnace slag (S) based alkali-activated materials (AAM) with the addition of ceramic waste for exposure to high temperatures (1000 °C). The temperature resistance of alkali-activated materials were described by measuring their surface morphology, gel structure and thermal damage degree, through NMR and UPV tests. At calcination temperature of 800 °C, the VA-based alkali-activated materials with ceramic waste shows ultrasonic velocity of 1962 m/s and a porosity of 17.30 %, indicating the prevention from gel structural collapse. As low calcination temperatures (≤600 °C), ceramic waste only functions as filler materials and reduces compressive strength of the alkali-activated materials. While at calcination temperature of 800 °C, there is an activity generated by the transformation of crystalline phases into amorphous phases in the ceramic waste, thus participates the alkali-activated reaction and increases compressive strength of the alkali-activated materials. At 1000 °C, the collapse of skeleton of the alkali-activated material is induced by thermal incompatibility of the matrix and thermal compression.

Optimizing solar-driven multi-generation systems: A cascade heat recovery approach for power, cooling, and freshwater production

The pursuit of an optimal solution for performance is essential in ensuring that a solar-driven multi-generation system functions efficiently. Due to the vast amount of solar power received by such systems, the production of significant waste heat ensues. Therefore, this study aims to propose and optimize a new cascade heat recovery method for a solar system that generates power, cooling, and freshwater. The designed configuration encompasses a parabolic trough solar collector to supply the required input energy of integration of a dual-pressure organic Rankine cycle with an ejector refrigeration cycle and an integration of a steam power cycle with a thermal vapor compression- multi-effect desalination. Employing both thermodynamic and economic assessments leads to attaining the performance indexes, which are involved in the optimization procedure. The outcomes of the simulation reveal that the net power, cooling, and freshwater productions are attainted at about 12.56 MW, 2.01 MW, and 138.3 kg/s. Also, the mass fraction 0.5–0.5 is an ideal composition for the highest values of net power and exergy efficiency, and these indexes are highly sensitive to changes in the temperature of vapor generator 3. The optimal operation mode provides an exergy efficiency of 14.76 % and a payback period of 5.49 years. In conclusion, the proposed cascade heat recovery method not only enhances the overall efficiency of the solar-driven multi-generation system but also demonstrates economic viability with a reasonable payback period.

Low-loss and broadband wafer-scale optical interposers for large-scale heterogeneous integration.

We design, fabricate, and demonstrate a low-loss and broadband optical interposer with high misalignment tolerance for large-scale integration of many chips using thermal compression flip-chip bonding. The optical interposer achieves flip-chip integration with photonic integrated circuit die containing evanescent couplers with inter-chip coupling loss of 0.54dB and ±3.53μm 3-dB misalignment tolerance. The loss measurement spectrum indicated wavelength-insensitive loss across O-band and C-band with negligible spectral dependence. Further, we demonstrate 1 to 100 wafer-scale equal power splitting using equal power splitters (EPS) and a path length matching design fabricated using a wafer-scale fabrication technique.