Thermal Technique Research Articles

Experimental evaluation and optimization of the heat pipes integrated thermoelectric generator using response surface methodology

In this study, integration of heat pipes with thermoelectric generators is proposed for the recovery of waste heat. Heat energy is transferred from a heat source to thermoelectric elements via heat pipes, enabling energy conversion. To dissipate excess heat from the system after conversion, additional heat pipes are positioned on the cold sides of thermoelectric elements. Cooling of the condenser sections of these heat pipes is facilitated using air flow provided by a fan. A novel approach in this study involves the innovative integration of heat pipes with thermoelectric generators. This integration provides a new pathway for optimizing waste heat recovery systems by combining advanced thermal management techniques with thermoelectric technology. Experiments conducted at different power inputs (12–42 W) and air velocities (0.4, 0.8, 1.2 m/s) determine the performance of the thermoelectric generator. Furthermore, a power usage efficiency analysis was conducted to discuss the applicability of the proposed method in electronics. At low air velocities, values below the ideal value of 1 were achieved. Experimental data were analyzed using response surface methodology to assess the impact of varying input parameters on the power output and efficiency of the thermoelectric generator. Optimization studies highlighted the importance of effectively cooling the cold side of thermoelectric elements. The highest power output and efficiency are achieved under conditions of 42 W power input, 1.2 m/s air velocity, and use of 4 heat sinks, yielding approximately 0.8 W and 2 %, respectively. Furthermore, the response surface methodology analysis indicated that the most significant effect on system outputs was the power input. Moreover, the results of this study lay the groundwork for future strategic advancements in thermoelectric generators, enhancing their role in sustainable energy solutions.

Single-use commercial bio-based plastics under environmental degradation conditions: Is their biodegradability and compostability a fact?

Evaluating compostability is increasingly essential for proving commercial bio-based cutlery or packaging since these materials must biodegrade under controlled conditions quickly. Utensils for eating represent Mexico's most popular consumer single-use materials, and Mexican regulations based on biodegradation or compostability are still vague and lack scientific evaluations. This study analyzed three bio-based polymeric materials (bags, dishes, and forks) from commercial brands following Mexican regulations and using various analytical techniques to verify their biodegradability and compostability. First, weight loss measurements, stress-strain tests, and topographic imaging were applied for preliminary observations at the macro scale up to 90 days of compostability. Besides, spectroscopy, microscopy, and thermal techniques indicate changes and behavior of the bio-based materials depending on the composition. The results suggest that bags exhibited the highest decomposition rate (80 %) compared to dishes and forks. Similarly, mechanical resistance indicates a reduction of 62 % for bags, 30 % for dishes, and almost none for forks. Texture image analysis revealed that the complexity and roughness of the materials increased over time, correlating with the physical changes observed. These results indicate minimal surface topography changes and higher stiffness for dishes and forks, indicating low biodegradability. SEM images supported these findings, showing surface degradation in bags and dishes but not in forks. FTIR and XRD analyses confirmed the presence of polyamide (bags) and polypropylene (dishes and forks). These results reduce biodegradation and differ from the claims made by manufacturers. The thermal analysis found similar results, indicating that the materials' thermal stability decreased after degradation, which is related to lower biodegradability and compostability. Overall, the study concluded only bags meet the criteria for compostability in national regulations. However, dishes and forks made of petroleum-derived polymers have higher resistance to natural and microbial degradation.

Carryover slag weight prediction under converter tapping process by applying attention-shifting infrared thermal mapping technique

The prediction model of actual slag weight under converter tapping process was constructed by applying attention-shifting infrared thermal mapping technique. Firstly, the linkage between programmable logic controller signal of the converter mechanical structure and the infrared thermal mapping detector image was realized to ensure the real-time monitoring of the whole tapping process. Images should be preprocessed to ensure a good distinction between the flowing liquid and background at the tapping beginning, furthermore to separated slag from liquid steel at the following process. Moreover, the use of attention-shifting block belonging to the infrared thermal detector was effect to obtain more accurate image distinction between the liquid steel and slag. Hence the gray degree threshold value was adjusted to 220–225 in the early stage, and the value was needed to be lowered to 170–176 in the end. After using the model, the slag weight was less than < 8.0kg/t when only slag-stopping awl was adopted in tapping process. The average weight of slag in converter was 7.3kg/t by using slag-stopping awl and sliding plate slag-blocking.

Characterization of Historical and Modern Leathers Using FTIR, XRD, SEM-EDX, and Thermal Techniques

Abstract A comprehensive study was conducted on four aged leather pieces of British origin that were utilized in book binding, dating back to the period between 1832 and 1860. The objective of this study was to characterize the thermal, structural, and deterioration properties of these historical leather fragments. Additionally, this study included two newly acquired leather samples of Indian provenance, proposed as potential replacements for this historical leather. The investigative process employed Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX). Through the FTIR analysis, distinct spectral shifts were identified in the amide A band, indicating a disruption of hydrogen bonding within the aged leather. XRD diffractograms revealed the presence of amorphous phases in the aged leather specimens, signifying the deterioration of their triple helical structure. Notably, DSC analysis provided insight into the denaturation of the collagen-tannin matrix inherent to the historical leather, underlining the transformative effects of time on this intricate material composition. Under SEM analysis, cracks, fibre deterioration, and a general weakening in structural integrity were observed in the aged leather fragments. The EDX data identified one of the new leather samples as chrome-tanned, while the remaining samples exhibited characteristics consistent with vegetable-tanned leather.

Detection of anti-personnel mines of the “leg breakers” type by analyzing thermographic images captured from a drone at different heights

A method for the detection of plastic anti-personnel mines called “ leg breakers ” is presented from images of the ground acquired remotely by a drone at heights between 1 and 5 m. The proposal achieved an accuracy of 92.13 % and a sensitivity of 82.4 % when evaluating the performance on 260 test images, a number higher than that used in previous works, and with mines buried in real terrain with the presence of vegetation. The above on images acquired on different dates with different environmental conditions and soil moisture. In addition, it was found that the method was adapted to three different thermographic cameras, being necessary only to adjust the gamma parameter associated with the thermal contrast enhancement technique used. It was corroborated that mines are easier to detect to the extent that they are buried more superficially, and when the flight height of the drone is between 1 and 2 m. Finally, it is highlighted that the proposal has the potential to be executed in processing systems onboard the drone, thanks to its algorithmic simplicity.

Novel environmentally-friendly 0D/3D TiO2@FeMoO4 binary composite with boosted photocatalytic performance: Structural analysis and Z-scheme interpretations

For efficient pollutant degradation under any extreme circumstances, TiO2-based photocatalyst being accessible and inexpensive will be a desirable engineering source satisfying excellent photocatalytic performance in an eco-friendly manner. Here, we report the unfolded way of designing the novel concept of Z-scheme heterojunction consisting of TiO2 and FeMoO4 via thermal techniques in which hydrothermal treatment was coupled sequentially by the calcination step. The well-aligned band structure of the developed composite, possessing numerous active sites, enhanced the separation of the generated charge carriers which in turn boosted the photocatalytic efficiency. The prepared photocatalysts were thoroughly investigated via different techniques like XRD, FTIR, XPS, SEM, TEM-EDS, Pl, UV-Vis diffuse reflectance, and Uv-Vis spectroscopy. The TiO2-8 wt.% FeMoO4 (TF 8%) photocatalyst displayed better photocatalytic performance for removing Basic Fuchsin dye (BF) in 20min than other counterparts under visible light irradiation. Furthermore, the probable photocatalytic mechanism was evidenced by XPS results and the trapping experiments. Trapping experiments revealed that •O2− and •OH radicals were the primary active species. The synthesized TF 8% photocatalyst has revealed outstanding durability after five successive recycles without change in the structural features which was confirmed by XRD analysis. This work could provide new perspectives into various environmental applications by utilizing highly efficient materials that have been strategically constructed.

Role of growth temperature on microstructural and electronic properties of rapid thermally grown MoTe2 thin film for infrared detection

In the field of electronic and optoelectronic applications, two-dimensional materials are found to be promising candidates for futuristic devices. For the detection of infrared (IR) light, MoTe2possesses an appropriate bandgap for which p-MoTe2/n-Si heterojunctions are well suited for photodetectors. In this study, a rapid thermal technique is used to grow MoTe2thin films on silicon (Si) substrates. Molybdenum (Mo) thin films are deposited using a sputtering system on the Si substrate and tellurium (Te) film is deposited on the Mo film by a thermal evaporation technique. The substrates with Mo/Te thin films are kept in a face-to-face manner inside the rapid thermal-processing furnace. The growth is carried out at a base pressure of 2 torr with a flow of 160 sccm of argon gas at different temperatures ranging from 400 °C to 700 °C. The x-ray diffraction peaks appear around 2θ= 12.8°, 25.5°, 39.2°, and 53.2° corresponding to (002), (004), (006), and (008) orientation of a hexagonal 2H-MoTe2structure. The characteristic Raman peaks of MoTe2, observed at ∼119 cm-1and ∼172 cm-1, correspond to the in-plane E1gand out-of-plane A1gmodes of MoTe2, whereas the prominent peaks of the in-plane E12gmode at ∼234 cm-1and the out-of-plane B12gmode at ∼289 cm-1are also observed. Root mean square (RMS) roughness is found to increase with increasing growth temperature. The bandgap of MoTe2is calculated using a Tauc plot and is found to be 0.90 eV. Electrical characterizations are carried out using current-voltage and current-time measurement, where the maximum responsivity and detectivity are found to be 127.37 mA W-1and 85.21 × 107Jones for a growth temperature of 600 °C and an IR wavelength illumination of 1060 nm.

Ohmic heating parboiling as a novel pretreatment to enhance the milling properties of Kodo millet

Dehulling of Kodo millet is difficult due to compact husk and small size. Pretreatment before milling has been shown to increase grain hardness and minimize milling loss. Ohmic heating (OH), a novel thermal technique could be employed for parboiling of Kodo millet to enhance the milling properties of millet. A study was conducted to evaluate the effect of ohmic heating parboiling (OP) on milling, physical properties, and nutritional composition of Kodo millet and compared it with conventional parboiling (CP). Kodo millet was soaked at 50°C, 60°C, and 70°C for 5 h, 2.5 h, and 1.5 h respectively to attain a moisture content of 30%. The soaked millet was parboiled for 20 min at a voltage gradient of 14 V/cm. Results showed that this treatment when compared to CP, was found to have higher hardness, head grain yield (HGY), and dehulling efficiency. HGY increased by 22.69% in CP and 28.03 % in OP, however, with an increase in the soaking temperature, HGY increased by 5.19-5.49%. A significant decrease was observed in the broken percentage. OP affected the nutritional profile as it retained higher protein than CP. This indicates that OP is superior in enhancing the milling properties of parboiled millet.

An open-loop and closed loop based passive thermal management techniques applicable to photovoltaic systems

Photovoltaic (PV) technology adoption in recent years has experienced significant growth due to its inherent advantages over alternative technologies. Nevertheless, there is a concern regarding performance deterioration due to high operating temperatures. Various thermal management methods have been studied to address this issue, each having its own advantages and disadvantages. Hence, a comprehensive review aimed at developing effective passive cooling techniques was undertaken and two techniques were finalized for outdoor testing viz. natural circulation loop based cooling (PV-NCL) and evaporative cooling (PV-EVP). Though the former version could drop module temperature by 7.4 °C–13.9 °C (Power output increment in the range of 3.5 %–6.7 %), this improvement was not sustained throughout the day due to factors such as flow resistance within the loop and a lack of convective cooling in the vicinity of the cooler. Subsequent experiments confirmed that loop resistance played a dominant role in this phenomenon. Additionally, concerns about water circulation in PV-NCL were resolved through a comparison with water duct-integrated PV. On the other hand, the innovative gravity-assisted water flow for evaporation method (PV-EVP) yielded more promising results, with a power output enhancement ranging from 3.7 % to 11.5 %. However, considering the in-field operational issues, PV-NCL with a modified design will likely be the best technique.

Electrical Performance and Degradation Analysis of Field-Aged PV Modules in Tropical Climates: A Comparative Experimental Study

Performance degradation is a prevalent phenomenon in solar photovoltaic systems globally, with varying aging profiles and effects depending on environmental and climatic conditions. This paper presents an extensive investigation of the electrical performance, aging mechanisms, and degradation analysis of field-aged PV modules under the tropical climate of Malaysia. Utilizing a combination of visual inspection, I-V curve measurement, and thermal imaging techniques, this research provides a comprehensive assessment of the electrical and thermal properties of field-aged PV modules from two locations in Malaysia over extended periods (8 years at UMPSA and 10 years at Pasir Mas). The multi-faceted approach of the study allows for a deeper understanding of the degradation process, offering insights into the causes and effects of higher current and lower voltage in aged modules. The study found the average annual degradation rates at UMPSA were 0.3% for open circuit voltage (Voc), 0.23% for short circuit current (Isc), 0.81% for maximum power (Pmax), and 0.35% for fill factor (FF) and at Pasir Mas, the average annual degradation rates were 1.124% for Voc, −0.166% for Isc, 1.276% for Pmax, and 0.43% for FF. The study also found that monocrystalline silicon (m-Si) panels experienced an average power degradation of 6.48%, while polycrystalline silicon (p-Si) panels showed a higher degradation of 12.76%. However, Thermal imaging revealed significant temperature variations across the modules, with hotspots reaching up to 11.2 °C above cooler areas in UMPSA panels and an even more pronounced 26.1 °C difference in Pasir Mas modules. These temperature disparities highlight the uneven heat distribution and potential performance issues in the panels. This research contributes to the understanding of PV module degradation in tropical climates and aligns with sustainable development, climate change mitigation efforts, and SDG 7 by promoting sustainable energy solutions.

Investigation of thermal diffusivity measurement technique based on photoacoustic signal response under the influence of three-dimesional heat transfer

In this study, we investigated the feasibility of measuring the thermal diffusivity of thermally thick solid material using the photoacoustic (PA) signal response in a three-dimensional heat diffusion state. For this purpose, we developed a heat conduction simulation model based on cylindrical coordinates to replicate the PA effect on three-dimensional heat diffusion. By numerical analysis, it was found that the phase of PA signal deviates from one-dimensional theory prediction when the lateral heat diffusion of the solid sample reaches the chamber wall of PA cell. Specifically, it was found that the phase lag inflects at the frequency where the sample’s thermal diffusion length μs is 0.91 mm at a chamber radius of 3 mm. By utilizing this correlation, the infection frequency can potentially provide the thermal diffusivity of the thermally thick sample. The experimental validation qualitatively confirmed that the phenomena observed in the numerical analysis occur in practice. However, quantitatively, the experimental results showed discrepancies from the numerical analysis, which is likely due to the influence of the radial distribution of laser intensity. Nonetheless, this issue can be resolved in practical applications through calibration using a reference sample. Numerical analysis suggested that for materials with thermal diffusivity lower than that of air, measuring thermal diffusivity could be seemingly impossible. However, the experimental results demonstrated that calibration with a reference sample having sufficiently lower thermal diffusivity than that of air effectively compensates for the influence of air’s thermal diffusion. The significant factor affecting the accuracy of thermal diffusivity determination with the proposed method is identifying the inflection frequency. It will be necessary to explore an appropriate method for determining the frequency by integrating multiple sources of information, such as simultaneously observing the amplitude of the PA signal.

Phosphorus-doped carbon nitride for enhanced supercapacitor performance and energy storage applications

Exploiting the advantages of graphitic carbon nitride doped with phosphorus (xP-CN) electrodes were designed for high-performance hybrid asymmetric supercapacitor via facile hydrothermal and thermal decomposition techniques. The structural, surface chemistry, functional and morphological characterizations evidence depict successful phosphorus incorporation in Carbon Nitride (CN). X-ray photoelectron spectroscopy analysis shows that phosphorus (P) atoms have replaced corner carbon atoms in the CN structure. These findings clearly demonstrate that the presence of phosphorus doping improves the electrochemical activity of the electrodes. The designed three-electrode system has a specific capacitance of 189.36 F/g with a current density of 1 A/g. Phosphorus doping has been discovered to play a significant role in improving both specific capacitance and cycling stability. The capacitance retention of the two-electrode solid-state device has 97.2 % after 5000 cycles. These electrochemical evaluations reveal that the xP-CN electrode exhibits superior electrochemical performances than pristine CN. This doping strategy for CN presents a novel and efficient approach for crafting high-performance supercapacitors.

Structural and Optical Characterization of Cu2Se0.8S0.2 Thin Films Deposited by Thermal Evaporation

Abstract A simple cost thermal evaporation deposition technique was used to prepare of Cu2SeS thin films on the substrates made of glass at RT with thickness ( 500 + − 20 ) nm . Structural, and optical properties of these films were investigated. The films were structurally characterized using X-ray diffraction XRD analyses, the film samples were morphologically characterized using atomic force microscopy (AFM), and optical UV-Vis spectroscopy was also to characterize the samples. The films have been treated at deferent temperatures (403, 453 &503) K for 1 hour, X-ray diffraction (XRD-with wavelength 1.54 A) study the structure properties of this films suggest a cubic structure and have prominent (111) orientation. AFM analysis, it is evident that Cu2SeS film is polycrystalline in nature, and that crystallite size and average grain size for films after annealing were increasing. The optical absorption coefficient (α) of the film was evaluated using absorbance spectra in the wavelength range (400-1100) nm. The direct band gap of about 2.2 eV, decrease by increasing annealing temperature, The structure and the optical characteristics of these films may have practical applications in renewable energy.

Thermal modeling and its role in management of bifurcation aneurysms and associated ischemic complications in the middle cerebral artery

Bifurcated aneurysm of cerebral artery is a common cerebrovascular disease, which can easily lead to serious ischemic complications. Traditional treatments face challenges of risk and effectiveness. Therefore, it is particularly important to explore new therapeutic strategies. In recent years, the application of thermal modeling techniques in medical biological systems has provided a new perspective for the analysis of hemodynamics and tissue thermal response. The purpose of this study was to investigate the role of heat model in the treatment of bifurcated cerebral artery aneurysms and their associated ischemic complications, and to evaluate its potential value in understanding disease mechanisms and optimizing treatment protocols. In this study, a three-dimensional thermal model was used to simulate the heat conduction and blood flow characteristics of the bifurcated parts of cerebral arteries. Combined with the clinical data of patients, the influence of the thermal model on the formation mechanism of aneurysms and the prognosis evaluation of ischemic complications were analyzed through numerical calculation and experimental verification. Compare the performance of different treatment methods in thermal models. The thermal model shows that the temperature distribution at the aneurysm site is closely related to the blood flow velocity, and the local temperature increase may promote thrombosis and lead to ischemic complications. The treatment regimen optimized by the thermal model showed significant improvement in the simulation, reducing the risk of complications and improving hemodynamic parameters. Heat model can reveal the dynamic relationship between blood flow and temperature in the study of cerebral artery bifurcation aneurysm, and provide theoretical support for clinical treatment.

Cold Sprayed Copper-Diamond Composites for Thermal Management of Semiconductor Packages

Thermal management is key to enabling increasingly powerful chips and heterogeneous integrated 2.5D/3-D systems. Composite materials with high thermal conductivities that can be placed at different levels of proximity to the die provide new solutions for heat dissipation. Here we report the fabrication of thick copper-diamond composite films using cold spray, which is a high-throughput, low-thermal-budget deposition technology. In cold spray, feedstock micro powder is accelerated in a specially designed nozzle by a heated pressurized gas and adheres to the substrate upon high-speed impingement. This process achieves higher deposition rates than other methods used in semiconductor manufacturing (such as electroplating). It also produces films that are denser and much less porous than ones produced by conventional thermal spray techniques. In this work, we first use process and thermal simulations to determine the requirements of the micro diamond powder feedstock, including the diamond core size, metal-clad thickness, core-clad interfacial resistance, and volume fraction to enable the cold spray of copper-diamond composites with thermal conductivities that are higher than copper. Subsequently, we perform a systematic characterization of the diamond powders from several suppliers, including the purity, metal oxygen content, particle morphology, and metal-clad adhesion. This characterization reveals the challenges of meeting all the specs using currently available diamond powders. Finally, we cold spray copper-diamond composite films on a variety of substrates with tunable thicknesses between 100 mm and 2 mm, achieving a thermal conductivity that is approximately 10% higher than cold-sprayed pure copper. Further improvement of the thermal properties relies on continued innovation in powder surface modification and powder storage/shipping methods.

Unveiling the Microstructural Features during Compression of a High-Modulus Mg-15Gd-8Y-6Al-0.3Mn Alloy Reinforced by a Large Volume of Al2RE Phases

Magnesium alloys with a high volume fraction of secondary phases exhibit inferior formability. Therefore, investigating their thermal deformation characteristics is critical for optimizing thermal processing techniques. In this work, isothermal compression experiments were performed on a Mg-15Gd-8Y-6Al-0.3Mn alloy with an elastic modulus of 51.3 GPa with a substantial volume of aluminum-rare earth (Al2RE) phases. The rheological behavior and microstructural evolution of the material were systematically investigated at varying temperatures (350–500 °C) and strain rates (0.001–1.000 s−1). The calculated thermal processing diagram indicates that the unstable region gradually enlarges with increased strain, and all unstable regions appear within the high-strain-rate, low-temperature domain. The ideal thermal processing range of the alloy is 350–500 °C at strain rates ranging from 0.001 to 0.016 s−1. Particle-stimulated nucleation and discontinuous dynamic recrystallization are both verified to be responsible for the recrystallized microstructure of the alloy. The recrystallized grains exhibit a relatively random crystallographic orientation. As recrystallization proceeds, the texture gradually transitions from a typical [0001] texture in the compression direction to a random texture accompanied by decreased texture intensity. This work sheds new light on the thermo-mechanical processing of high-modulus Mg alloys, which could help design suitable processing techniques for related materials.

Advances in Adenomyosis Treatment: High-Intensity Focused Ultrasound, Percutaneous Microwave Therapy, and Radiofrequency Ablation.

Background/Objectives: Adenomyosis is a debilitating gynecologic condition that affects both multiparous older women and nulliparous younger women, inducing a variety of symptoms such as dysmenorrhea, menorrhagia, and infertility. Thermal ablation techniques are new procedures that have been proposed for the treatment of adenomyosis. They include high-intensity focused ultrasound (HIFU), percutaneous microwave ablation (PMWA), and radiofrequency ablation (RFA). Because thermal ablation techniques are minimally invasive or noninvasive, fertility is not impaired while symptoms improve. In addition, hospital stays and financial costs are generally reduced, increasing the interest in these alternative management options. Methods: In this narrative review, we conducted a thorough literature search of PubMed/Medline from the database inception to September 2022. In our search, we focused on noninvasive treatment methods such as HIFU ablation, RFA ablation, and PMWA as well as adenomyosis-specific terms and noninvasive techniques (ultrasonography, ultrasound, or magnetic resonance imaging). The queries were a combination of MeSH terms and keywords. The search was limited to the English language. Abstracts were screened according to their content, and relevant articles were selected. Results: Overall, the results showed that the above-mentioned ablation techniques are effective and safe in providing adenomyosis treatment. Lesion size and uterus volume are reduced, leading to considerable symptom alleviation with all three methods. Positive results concerning safety and fertility preservation have been described as well. Conclusions: Nonetheless, more research is required in this field to compare the efficacy and safety of different ablation techniques with traditional therapies. Such research will help improve these procedures and their associated decision-making processes.

Cryoablation of osteoid osteomas: Is it a valid treatment option?

Osteoid osteoma is a benign bone tumor with characteristic clinical symptomatology. The selected method for its treatment is percutaneous radiofrequency ablation. However, percutaneous cryoablation is an alternative method with certain advantages. To evaluate percutaneous computed tomography (CT)-guided cryoablation for the treatment of osteoid osteoma in young patients and adults. A total of 25 patients were treated with percutaneous CT- guided cryoablation for osteoid osteomas between October 2020 and March 2023 at a single institution. All patients were above 14-years-old (mean age, 24-years-old), and all procedures were performed under local anesthesia. Of the 25 patients, 8 were female and 17 were male. Tumor sites included the femur (n = 9), medial malleolus (n = 4), sacral ala (n = 4), facets (n = 4), humerus (n = 3), and tibia (n = 1). One cryoprobe was used in each procedure and, when possible, the lesion was covered by the ice-ball using an extraosseous position without penetrating the nidus. All necessary thermal protective techniques were used depending on the anatomical structure at risk. All patients treated had complete response (100% clinical success rate) starting on the day of the procedure. Technical success was achieved in all cases. Visual analog scale (VAS) scores at 1 year were 0, compared to a mean VAS score of 8.5 ± 1 (SD) before the procedure. No recurrences were reported at the 1-year follow-up and no complications were observed. In 11/25 cases, an extraosseous position of the cryoprobe was used with less procedural time achieving technical and clinical success and no complications with less patient discomfort. All patients were discharged from the hospital on the same day as the procedure. Cryoablation of osteoid osteomas is an efficacious and safe procedure with durable clinical results. Its greatest advantage is that the procedure can be performed under local anesthesia using an extraosseous position of the cryoprobe when possible.

Optimizing microchannel heat sink performance: Effect of step-gap design and contraction on flow boiling stability and heat transfer

Liquid cooling with cold plates (microchannels) is an advanced thermal management technique used in high-performance electronics and computing systems. Conventional microchannels have a straight fin array that shows instabilities during two-phase flow boiling. The present experimental investigation continues previous studies to explore the effects of combining the contraction before the microchannels (CBM) and a step gap above the microchannels (SGAM) in the enclosed cover of the heat sink to improve two-phase convective boiling performance. The microchannel heat sink is sized at 49 mm × 52 mm, featuring a channel width of 200 μm and a height of 3 mm, with a fin thickness of 200 μm. Dielectric fluid HFE-7000 was used as the working fluid, and the mass flux ranges from 30 to 260 kg/m2·s, with concentrated heat flux varying from 50 to 156 W/cm2. The results reveal that the combination configuration significantly reduces pressure drop by approximately 23–56 % lower than that of the plain (Conventional) configuration. This combination of configurations is especially effective at a high heat flux above 100 W/cm2. Experimental results indicate that the combination configuration lowers wall superheat temperatures compared to the plain sample, therefore enhancing the overall heat transfer coefficient by 30–154 % across the tested mass flux range. These findings underscore the potential of combining contraction before microchannels (CBM) and step gap above microchannels (SGAM) configurations to significantly enhance flow boiling stability and heat transfer performance while incurring a much lower pressure drop penalty.

Unearthing waste resources: Nano‐adsorbents from complex packaging waste for fluoride detoxification of water

AbstractThis study investigates the synthesis and characterization of Al2O3 nanoparticles derived from multilayered packaging (MLP) waste, specifically postconsumer coffee capsules, and evaluates their efficacy in fluoride adsorption from aqueous solutions. The nanoparticles were synthesized using a facile thermal degradation technique followed by leaching and precipitation processes. Characterization techniques, including inductively coupled plasma‐mass spectroscopy, XRF, Fourier transform infrared spectroscopy, X‐ray diffraction, and transmission electron microscope, confirmed the formation of γ‐Al2O3 nanoparticles with a cubic crystal structure. The adsorption process was found to be endothermic and spontaneous, with a maximum adsorption capacity of 9.60 mg/g. Kinetic studies revealed that the pseudo‐second order model best described the adsorption process, indicating a complex multistep mechanism involving both physisorption in the initial rapid adsorption and chemisorption in the latter slower phase. The Freundlich–Langmuir isotherm provided the best fit for equilibrium data suggesting a complex adsorption mechanism involving both homogeneous and heterogeneous surface interactions. The presence of competing anions, particularly carbonate and phosphate, significantly affected the adsorption efficiency. This research demonstrates the potential of upcycling MLP waste into valuable adsorbents for wastewater treatment applications, offering both environmental and economic benefits.