Conventional Thermal Processing Research Articles

The Influence of Ohmic Heating on Degradation of Food Bioactive Ingredients

Ohmic heating is an alternative thermal treatment considered to be less destructive to bioactive compounds compared with conventional thermal processes. Bioactive compounds are well recognized as an important group of ingredients due to their nutritional value and their contribution to human health. The retention of these constituents during a thermal process, e.g., blanching, pasteurization, and sterilization, is a big challenge in the food industry and relevant industries. Furthermore, Ohmic heating as a moderate heating method also seems to be a promising technique for extraction of bioactive compounds. In the present study, the effects of Ohmic heating on degradation of different bioactive compounds such as phenolics, carotenoids, and vitamins, along with their degradation kinetics, have been reviewed.

Investigation on breakage behaviour of oil shale with high grinding resistance: A comparison between microwave and conventional thermal processing

Co-processing (e.g. co-combustion) of oil shale with other fuels like coal to derive energy could mitigate environmental-related problems associated with oil shale whilst enhancing thermal efficiency. However, reducing the size of oil shale particles to that similar to coal for better handling and combustion is energy-intensive given its high grinding resistance. Therefore, it is essential to improve the grindability of oil shale. In this study, two Chinese oil shales were investigated. The sieved samples were pre-treated and crushed to study the failure mechanisms, as well as changes in uniaxial peak strength and specific breakage rate in comparison to that of untreated samples; and how chemical properties were affected after either conventional or microwave-enhanced thermal processing. Results show that the uniaxial compressive strength of oil shale was significantly reduced whilst the breakage rate increased after a short exposure to microwave irradiation. The improvement was approximately 50 % higher than that observed after conventional heating. Hence, results suggest that microwave processing could lead to a more significant and rapid improvement in oil shale milling compared to conventional pre-heating, and without adversely affecting fuel quality. The simple microwave pre-treatment can potentially widen the utilization of oil shale, particularly when homogeneity is necessary during co-processing.

Nitrogen Effects in Additively Manufactured Martensitic Stainless Steels: Conventional Thermal Processing and Comparison with Wrought.

The microstructures of additively manufactured (AM) precipitation-hardenable stainless steels 17-4 and 15-5 were investigated and compared to those of conventionally produced materials. The residual N found in N2-atomized 17-4 powder feedstock is inherited by the additively produced material, and has dramatic effects on phase stability, microstructure, and microstructural evolution. Nitrogen is a known austenite stabilizing element, and the as-built microstructure of AM 17-4 can contain up to 90 pct or more retained austenite, compared to the nearly 100 pct martensite structure of wrought 17-4. Even after homogenization and solutionization heat treatments, AM 17-4 contains 5 to 20 pct retained austenite. In contrast, AM 15-5 and Ar-atomized AM 17-4 contain<5 pct retained austenite in the as-built condition, and this level is further decreased following post-build thermal processing. Computational thermodynamics-based calculations qualitatively describe the observed depression in the martensite start temperature and martensite stability as a function of N-content, but require further refinements to become quantitative. A significant increase in the volume fraction of fine-scale carbide precipitates attributed to the high N-content of AM 17-4 is also hypothesized to give rise to additional activation barriers for the dislocation motion required for martensite nucleation and subsequent growth. An increase in the volume fraction of carbide/nitride precipitates is observed in AM 15-5, although they do not inhibit martensite formation to the extent observed in AM 17-4.

Ultrases Uygulamasının Meyve Sularının Biyoaktif Bileşenleri Üzerine Etkisi

Geleneksel ısıl işlem uygulamalarının meyve suyu kalite özellikleri üzerindeki olumsuz etkileri sebebiyle, tüketicinin minimum işlenmiş, tazeye daha yakın özellikte gıda talebi, ısıl olmayan teknolojilerin uygulanması ile karşılanabilmektedir. Besin değerinde azalma, renk maddesi ve vitamin kayıpları ile istenmeyen lezzet ögelerinin oluşumunu düşük seviyelere indirmek ultrases uygulamasıyla mümkün olabilmektedir. Özellikle gıdanın biyoaktif bileşen içeriği gibi kalite parametrelerini koruması veya iyileştirmesi gibi avantajları, son yıllarda ultrases uygulamasına olan ilgiyi arttırmıştır. Bu çalışmada ultrases uygulamalarının meyve sularında bulunan biyoaktif bileşenler üzerine etkisi, askorbik asit, antosiyanin, flavonoid ve karotenoid içeriği üzerine etkileri olmak üzere ayrı ayrı derlenmiş ve değerlendirilmiştir. Çalışmalarda, ultrases uygulamasının meyve sularının biyoaktif bileşen içeriğinde artış, azalma ya da önemli düzeyde olmayan değişimlere neden olması, ultrases işlem parametrelerinin yanı sıra meyve suyu matriksindeki farklılıklardan kaynaklanabilmektedir. Bu nedenle, farklı meyve sularında ultrases teknolojisinin uygulanması ve her meyve suyu için işlem koşularının optimize edilmesinin oldukça önemli olduğu değerlendirilmiştir.

Microwave processing of carbon fibre polymer composites: a review

Microwave processing of carbon fibre-reinforced polymer (CFRP) composites is gaining increasing attention as an alternative to conventional thermal processing techniques. It has the potential to reduce part processing times and alleviate the bottleneck that often exists in composite component production. The present study reviews the current research and the state-of-the-art of microwave processing of CFRP composites. The benefits and limitations of microwave processing compared with traditional thermal processing methods are examined. The mechanical properties of microwave-cured composites are compared against conventionally-cured counterparts with varying levels of success. Current industrial microwave heating technologies are also examined. It is evident that microwave processing of polymer composites is promising but has notable limiting factors which have stunted its uptake in industry. Due to their prevalence in literature, CFRP composites with thermosetting matrices are the focus of this review. However, potential applications to carbon fibre-reinforced thermoplastics are also briefly described.

Effects of high-pressure processing on fungi spores: Factors affecting spore germination and inactivation and impact on ultrastructure.

Food contamination with heat-resistant fungi (HRF), and their spores, is a major issue among fruit processors, being frequently found in fruit juices and concentrates, among other products, leading to considerable economic losses and food safety issues. Several strategies were developed to minimize the contamination with HRF, with improvements from harvesting to the final product, including sanitizers and new processing techniques. Considering consumers' demands for minimally processed, fresh-like food products, nonthermal food-processing technologies, such as high-pressure processing (HPP), among others, are emerging as alternatives to the conventional thermal processing techniques. As no heat is applied to foods, vitamins, proteins, aromas, and taste are better kept when compared to thermal processes. Nevertheless, HPP is only able to destroy pathogenic and spoilage vegetative microorganisms to levels of pertinence for food safety, while bacterial spores remain. Regarding HRF spores (both ascospores and conidiospores), these seem to be more pressure-sensible than bacterial spores, despite a few cases, such as the ascospores of Byssochlamys spp., Neosartorya spp., and Talaromyces spp. that are resistant to high pressures and high temperatures, requiring the combination of both variables to be inactivated. This review aims to cover the literature available concerning the effects of HPP at room-like temperatures, and its combination with high temperatures, and high-pressure cycling, to inactivate fungi spores, including the main factors affecting spores' resistance to high-pressure, such as pH, water activity, nutritional composition of the food matrix and ascospore age, as well as the changes in the spore ultrastructure, and the parameters to consider regarding their inactivation by HPP.

One-step fabrication of thermal sprayed polymer coating on metals

This study presents the polymer coating onto metal-based structures by the thermal spray process. The deposition of polymers onto metal substrate has been developed by controlling the temperature in conventional thermal spray process. Properties of final polymer coating are investigated, such as microstructural, crystallization, mechanical, friction and corrosion properties. The objective of this is to deposit a polymer coating by controlling temperature in conventional thermal spray process and evaluate the coating properties for specific applications such as polymer coating on vacuum pump screws as abrasion resistant coating and on Kevlar fabric to provide strength for bullet proof soft armor vest for defense application. This study reports that as-sprayed coating can be used without post processing like annealing and filing. As-sprayed PEEK coating has a considerable hardness and adhesion strength found to be 17 ± 5 HV, 16 ± 3.0 MPa, respectively. However, post annealing treatment may introduce further improvements in wear and friction resistant properties of the final polymer coating system. The microhardness value has increased from 17 HV to 29 HV in average. The annealed semi-crystalline coatings exhibit the slightly lower friction coefficient than amorphous coating (as-sprayed); 0.31 in average versus 0.36. The wear rate of annealed coating is lower than the as-sprayed coating, decreased by approx 50% (10.5 in average versus 20.5 × 10− 6 mm3 N−1 m−1). The PEEK coating protects the base metal against corrosion and life against corrosion is found to be 25.4 μm.y−1; 81.75% efficiency in reduction of corrosion with respect to steel exposed in 5% NaCl solution.

Dielectric Properties and Heating Properties of Aniseed Powder with Radio Frequency Heating

Microbial contamination is currently a major safety issue in low moisture foods. Current sterilization and pasteurization practices, such as conventional thermal processing involving conductive heat transfer to inactivate pathogens, appear inadequate to address the contamination problem in low-moisture foods, which require long time heating, leading to quality deterioration with significant loss of colour and flavour. Radio Frequency (RF) heating has great potential in pasteurization of low moisture foods and offers the possibility to rapidly inactivate microorganisms while maintaining the food quality. Aniseed powder as one of typical low moisture foods possesses significant risk of microbial contamination. This study was to develop RF heating process to inactivate microorganisms in aniseed powder. The dielectric properties (i.e. dielectric constant (ε') and dielectric loss factor (ε'')) of aniseed powder, the influences of processing conditions on heating properties and the inactivation of microorganisms in aniseed powder were all studied in this research. Results showed that ε' and ε'' of aniseed powder decreased with an increase in frequency from 6.78 MHz to 47.46 MHz but then fluctuated between 300 and 2745 MHz. The overall change of ε' and ε'' ultimately exhibited a downward trend. Under a constant frequency treatment, ε' and ε'' of aniseed powder increased with an increase in moisture content, whereas the penetration depth decreased. Particle size showed no significant effects on the dielectric properties, heating rate and penetration depth. With an increase in RF processing time, the heating rate of the sample increased and adding the rolling-over operation step helped to improve the uniformity of RF heating. After processing for 100 s, the temperature of aniseed powder could increase to 60 °C, and the number of microorganism in aniseed powder was reduced by 6.18 logs when time extended to 150 s.

Preparation of carbon nanostructures from medium and high ash Indian coals via microwave-assisted pyrolysis

This study is focused on valorizing low value and low quality Indian coals via microwave pyrolysis to produce good quality carbon nanostructures in the heat-treated coal char. The effects of operating conditions such as coal type, coal:susceptor (Fe) mass ratio, and microwave power on product yield and quality are evaluated. The quality of the heat-treated coal char was assessed using different characterization techniques such as electron microscopy, porosimetry, X-ray diffraction, and Raman spectroscopy. The addition of Fe enhanced the heating rates, and led to the formation of carbon nanotubes and nanoparticles. Increasing the proportion of Fe resulted in increase in size of nanotubes and nanoparticles, which is attributed to the fusion of small tubes and particles caused by enhanced localized heating. The yield of carbon nanostructures was more from medium ash (~45%) than from high ash coal (~37%) due to the high fixed carbon and low ash content in the former. In addition to char, coal tar and non-condensable gases were characterized. The major compounds in the coal tar were aromatic hydrocarbons, simple phenols and aliphatic hydrocarbons. Hydrogen and methane were the major gases from medium ash coal, while hydrogen, methane and CO were produced in significant quantities from high ash coal. Microwave-assisted pyrolysis is shown to be a promising process to produce carbon nanostructures in a short time period as compared to conventional thermal processes.

Preparation and nanofiltration properties of thin supported meso-porous ceria membranes

Thin film meso-porous ceria membranes were prepared by colloidal deposition of ceria precursor nanoparticles on ~2 mm thick macro-porous α-Al2O3 supports, followed by rapid thermal processing at 600 °C or conventional thermal processing at 500 °C. Stable ceria precursor nanoparticles with a diameter of 4–6 nm were made by ultrasound-assisted precipitation and stabilization with bicine. The ceria precursor concentration, poly-vinyl alcohol concentration in the deposition dispersion, and the coating times were varied to obtain the optimum membrane deposition. The effect was investigated of deposition conditions on membrane thickness, water permeation and salt rejection at ambient circumstances. Meso-porous ceria membranes made on monolithic macro-porous α-Al2O3 supports with a bulk pore size of 100 nm and a porosity of 30% exhibited high salt rejection for aqueous solutions with low salt concentrations. For instance at a pH of 4 and a trans-membrane pressure of 0.68 MPa, a ceria membrane had stable maximum rejections of 83% and >95% for 1 mol/m3 NaCl and CaCl2, respectively. At a concentration of 1 mol/m3, >81% Na2SO4 was rejected at a pH of 10. These salt-rejections are caused by surface charging of the porous ceria membrane structure by chemi-sorption of H+, Ca2+ and SO42−. Ceria membrane structures with just monolithic α-Al2O3 supports had a volumetric water permeance of 5.9 L/(m2 h bar). To increase the overall permeance, a ceria membrane was deposited onto a ~10 μm thick macroporous α-Al2O3 layer, in turn supported by a 2 mm thick and more permeable macroporous α-Al2O3 support. With this three-layer structure a salt rejection of 73% was obtained for 1 mol/m3 NaCl at pH = 4 and 25 °C with an overall volumetric water permeance of 43 L/(m2 h bar). During the experiments no obvious changes in transport properties occurred while the membranes were also fully stable during 6 weeks exposure to ultrapure water at 60 °C. This indicates a complete stability in aqueous solutions at room temperature and moderate pH.

Machine-based learning of predictive models in organic solvent nanofiltration: Pure and mixed solvent flux

During the last decades, the interest in organic solvent nanofiltration (OSN), both in academia and industry, increased substantially. OSN provides great potential for an energy-efficient separation of complex chemical mixtures with dissolved solutes in the range of 200–1000 Dalton. In contrast to conventional thermal separation processes, the pressure-driven membrane separation operates at mild temperatures without energy intensive phase transition. However, the complex interaction of different phenomena in the mass transfer through the membrane complicate the prediction of membrane performance severely, such that OSN is virtually not considered as an option in conceptual process design. Several attempts have been made to determine predictive models, which allow the determination of at least pure solvent flux through a given membrane. While these models correlate different important physical properties of the solvents and are derived from physical understanding, they provide a limited accuracy and not all of their parameters are identifiable based on available data. In contrast to previous approaches, this work presents a machine learning based approach for the identification of membrane-specific models for the prediction of solvent permeance. The data-driven approach, which is based on genetic programming, generates predictive models that show superior results in terms of accuracy and parameter precision when compared to previously proposed models. Applied to two respective sets of permeation data, the developed models were able to describe the permeance of various solvents with a mean percentage error below 9% and to predict different solvents with a mean percentage error of 15%. Further, the method was applied to solvent mixtures successfully.

Upgrading of Venezuela extra-heavy oil vacuum residue by two-step thermal treatment

A two-step thermal treatment approach (TSTT), composed by mild thermal treatment and deep thermal cracking, is proposed to upgrade the Venezuela extra-heavy oil vacuum residue. In comparison to the conventional one-step thermal processing, the use of TSTT increased the liquid yield by 4.4 wt% and reduced the coke yield by 4.0 wt%. The cycle of light gas-oil as hydrogen donor significantly enhanced the percentage of diesel subfraction (200–350 °C) in the liquid product.

Effects of electrotechnologies on enzymes in foods and food model systems

Electrotechnologies gained increased popularity as non-thermal processing of foods as they offer many advantages over conventional thermal processing. These technologies effectively inactivate microorganisms, enhance the processing efficacy at lower treatment intensity (e.g. pressing, pre-treatment for drying, extraction etc.) with preservation of nutritional, functional and sensory characteristics of processed foods. Moreover, these technologies can be applied for targeted and controlled enzymatic treatments. Structural and conformational changes under these treatments may influence enzymatic inactivation, but also activate enzymes or enhance their activity. Therefore, the enzyme characteristics and treatment conditions could be finely tuned toward desirable properties and effects in food production and processing.

The effects of conventional thermal, microwave heating, and thermosonication treatments on the quality of sugarcane juice

The present work describes the effects of three different heat treatments to extend the shelf life and quality of sugarcane juice. Freshly extracted sugarcane juice samples were thermally treated by microwave heating; thermosonication, and conventional thermal processing to evaluate their effects on microbial loads, physicochemical properties, color changes, and quality parameters such as total phenolic content, antioxidant activity, and reducing sugars. Among all treatments, low power microwave was shown to be the best treatment by completely reducing the microbial loads to nondetection. The treatment was also able to preserve the total phenolic content (3.53), antioxidant activity (21.58), maintain the quality of physicochemical attributes, and minimize the overall color changes (ΔE* 4.76) as compared to other treatments. Overall, the present work provides an overview of alternative sugarcane juice treatments which could also be combined with hurdle technology that can further improve the quality and global market of the juice. PRACTICAL APPLICATIONS: The present work seeks to improve the acceptance, quality, and shelf life of sugarcane juice by comparing conventional heating, microwave heating, and thermosonication. Currently, there are limited studies that emphasize to improve its quality as sugarcane juice is easily spoiled. The treatments proposed in this study are effective, cheap, more practical, and sustainable to be upscale for the larger production of sugar cane juice. This treatment could also be combined with hurdle technology or packaging technology that can further improve the quality, shelf life, and marketability of the juice.

Role of plasma properties in controlling crystallinity and phase in oxide films grown by plasma-enhanced atomic layer epitaxy

Plasma-enhanced atomic layer epitaxy (PEALE) is a cyclic atomic layer deposition process that incorporates plasma-generated species into one of the cycle substeps to achieve layer-by-layer crystalline growth. The addition of plasma generally provides unique gas phase chemistries and a substantially reduced growth temperature compared to thermal approaches. Indeed, when properly configured, PEALE systems can deliver high-quality crystalline films with structural characteristics that rival those grown by conventional thermal equilibrium growth processes such as molecular beam epitaxy or metalorganic chemical vapor deposition. However, the inclusion of plasma also adds a complex array of reaction pathways that can be challenging to understand and control. This work focuses on the use of plasma diagnostics to inform the choice of process conditions for PEALE. Optical emission and vacuum ultraviolet emission spectroscopy, as well as spatially resolved Langmuir probe measurements, are employed to characterize an inductively coupled plasma source used for the growth of epitaxial TiO2 and Ga2O3 films on sapphire. Under plasma conditions with large concentrations of atomic oxygen and significant ion energy (30–50 eV), highly crystalline TiO2 and Ga2O3 films were grown, indicating that both reactive neutral chemistry and ion energy are important in these processes.

Effect of thermal and non-thermal techniques for microbial safety in food powder: Recent advances.

Food powders are appreciated worldwide, as it enables food to be preserved for an extended period without significant loss of quality, even under the ambient storage condition. However, it is evidenced that the development of resistant microbial spore and viable microbial cells is a matter of concern even in low moisture foods like food powders. For microbial inactivation, the strategy generally applied is the implication of conventional preservation methods, such as heat treatment which is greatly accompanied by degradation of nutritional organoleptic properties. To overcome the shortcomings of conventional thermal processing, a set of advanced or emerging technologies are being developed which can inactivate the microbial spores and viable microbial cells capable of surviving with maximum retention in the nutritional or organoleptic profile. The examples include infrared heating, microwave heating, radiofrequency heating, instant control pressure drop technology, high-pressure processing, pulsed electric field, pulsed light, ozone processing, and cold plasma. In this review, the potential of different advanced thermal and non-thermal technologies towards the inactivation of spores and viable cells of microorganisms in food powders has been highlighted precisely along with their mechanism of action. The summary of the literature encompassing the use of different processing techniques will help the readers to understand the underlying mechanism of microbial inactivation associated with each processing techniques applied to powders. Eventually, this information will help them to select the suitable technique (individual or in combination with another counterpart) to inactivate spores and viable cells in a specific food powder.

(Invited) 3D Conformal Printing of High-Performance and Flexible Thermoelectric Devices Using Colloidal Nanocrystals

The flexible thermoelectric generator (f-TEG) is a very promising technology for energy harvesting to enable self-powered wireless sensors and wearable devices, an area of exponential growth. Here, we present a scalable and cost-effective additive manufacturing process to fabricate f-TEGs using colloidal nanocrystals, and an innovative and highly efficient photonic sintering method to sinter large areas of printed films using pulsed light. Flexible TE films and devices were printed using screen printing and aerosol jet printing, followed by pulsed photonic sintering process. The pulsed sintering confines the delivered thermal energy within the printed film region without over heating the substrate, enabling TE film sintering on flexible polymer based substrates with relatively low melting point. In addition, the pulsed sintering limits grain size growth due to an ultrafast heating and cooling process, and lower thermal conductivity can be achieved than films sintered by conventional thermal processing. The p-type and n-type printed films demonstrate peak ZTs of 1 and 0.43 near room temperature along with superior flexibility, which is among the highest reported ZT values in flexible thermoelectric materials. A flexible thermoelectric device fabricated using the printed films produces a high power density above 19 mW/cm2 with 80 ºC temperature difference between the hot side and cold side. The additive printing and photonic sintering can enable a highly scalable and low-cost roll-to-roll manufacturing process to transform high-efficiency colloidal nanocrystals into high-performance and flexible TEG devices for widespread applications.

Fundamental Understanding of Redox Characteristics of Defect-Rich Holey Graphene for Lithium Ion Energy Storage Devices

Graphene has received intensive research interest as a promising electrode material for energy storage applications because of its unique combination of properties including high intrinsic electrical conductivity, good mechanical flexibility, exceptional theoretical surface area and capacitance. The approaches to engineer graphene-based materials mostly involve functionalization, structural modification for the porous structure with abundant defective sites or incorporating other redox-active substances as the composite. Among various oxygen functional groups on graphene oxide, carbonyl group is regarded as the most active group to provide reversible redox reactions with Li ions.[1] The conservation of the redox-active carbonyl group during conventional chemical and thermal reduction processes of graphene oxide has so far shown only limited effect. Thus, the selective reduction process of oxygen functional groups on graphene oxide is a particularly promising strategy to enhance the charge storage performance on highly porous nanostructures. In this study, we prepared reduced holey graphene oxide with a combination of chemical etching and selective reduction processes, proposing a high performance cathode material for rechargeable lithium ion batteries. In addition, in order to further enhance the charge storage performance, a redox-active organic compound is introduced onto the holey graphene oxide structure. References T. Y. Liu, K. C. Kim, R. Kavian, S. S. Jang, S. W. Lee, Chem. Mater. 27, 3291-3298 (2015).

(Invited) Low-Energy Plasma Enhanced Chemical Vapor Deposition and In-Situ Doping for Junction Formation in Group-IV Semiconductor Devices

In novel semiconductor devices, such as a tunnel field-effect transistor (TFET) [1,2], a resonant-tunneling device [3-5] and a semiconductor spin qubit [6], energy-band modulation in group -IV semiconductors using nanometer-scale heterostructure and local doping [7] with suppressed intermixing is a key technology. Additionally, 2-dimensional (2D) nanosheet semiconductor materials (e.g. graphene, silicene, tungsten disulfide and so on) are aggressively investigated [8]. In such a trend, as well as conventional low-temperature thermal processes, utilizing a low-energy plasma process has been explored. We have clarified that low-energy Ar plasma irradiation effectively induces surface reaction and epitaxy of Si-based group-IV semiconductor on Si(100) [9-19]. Our efforts in development of such material processing utilizing low-energy Ar plasma process will be presented. Without substrate heating, low-energy electron-cyclotron-resonance (ECR) Ar plasma chemical-vapor deposition (CVD) process has enabled epitaxy of strained/unstrained films of group-IV materials (Si, Ge, Si-Ge alloy and Si-C alloy) with in-situ doping and an atomic-layer (AL) doped structure (Fig. 1) [9-19]. Especially in the TFET, sub-nanometer-order (atomic-order) abrupt profile control of impurities (B or P) concentration will be examined in epitaxy and in-situ doping. As a typical issue in our plasma CVD, it is considered that surface segregation of impurity during Si deposition occurs and degrades the profile abruptness near the interface. However, it has been demonstrated that the abruptness can be improved by atomic-layer doping technique [14,18]. Additionally, it is found that electrical activity of B doped in Si tends to be lowered especially at higher concentration than 1019 cm-3, while higher-energy plasma irradiation effectively improves the activity. These imply that semiconductor device process can be performed at lower temperatures where unexpected thermal diffusion and reactions are effectively suppressed. Our recent challenge is penta-silicene formation from epitaxial Si nanosheet. We believe that 2D materials as a novel semiconductor will be obtained not only by atomically-controlled epitaxy of heterostructures but also by reconstruction of atomic arrangement at surface. Here, our target is penta-silicene transformed from a 3-atomic-layer-thick Si nanosheet, which is different from the diamond structure. Our concept is crystal structure transformation in the Si nanosheet, and this is based on long-range coordinated and double-sided surface reconstruction on Si(100) to form the penta-silicene (Fig. 2) [15]. Because penta-silicene has a 3-dimensional structure composed of 3 atomic layers (similar to tungsten disulfide), it is expected to be more stiff and stable physically than monolayer of hexa-silicene. Realization methods of the penta-silicene on Si wafer for large-scale integration of the penta-silicene devices are now in progress. After formation of penta-silicene, control of interface structure between the penta-silicene and gate insulator will be one of the important issues to control interface structure. From the view-point of material science and control of the interfaces in semiconductor, development of process technology must be proceeded further. Such efforts will encourage smart electronic devices for enabling artificial intelligence and higher security in the next-generation information society. Acknowledgements This work was partly supported by Grant-in-Aid for Challenging Exploratory Research (No. 18K18987) from the JSPS in Japan and the Cooperative Research Project Program of the Research Institute of Electrical Communication, Tohoku University.

QbD approached comparison of reaction mechanism in microwave synthesized gold nanoparticles and their superior catalytic role against hazardous nirto‐dye

Microwave irradiation (MI) process characteristically enables extremely rapid “in‐core” heating of dipoles and ions, in comparison to conventional thermal (conductance) process of heat transfer. During the process of nanoparticles synthesis, MI both modulates functionality behaviors as well as dynamic of reaction in favorable direction. So, MI providing a facile, favorable and alternative approach during nanoparticles synthesis nanoparticles with enhanced catalytic performances.Although, conventionally used reducing and capping reagents of synthetic origin, are usually environmentally hazardous and toxic for living organism. But, in absence of suitable capping agent; stability, shelf life and catalytic activity of metallic nanoparticles adversely affected. However, polymeric templates which emerged as suitable choice of agent for both reducing and capping purposes; bearing additional advantages in terms of catalyst free one step green synthesis process with high degree of biosafety and efficiency.Another aspect of current works was to understand role of process variables in growth mechanism and catalytic performances of microwave processed metallic nanoparticles, as well as comparison of these parameters with conventional heating method. However, due to poor prediction ability with previously published architect OFAT (One factor at a time) design with these nanoparticles as well as random selection of process variables with their different levels, such comparison couldn't be possible.Hence, using gum Ghatti (Anogeissus latifolia) as a model bio‐template and under simulated reaction conditions; architect of QbD design systems were integrated in microwave processed nanoparticles to establish mechanistic role these variables. Furthermore, in comparison to conventional heating; we reported well validated mathematical modeling of process variables on characteristic of nanoparticles as well as synthesized gold nanoparticles of desired and identical dimensions, in both thermal and microwave‐based processes. Interestingly, despite of identical dimension, MI processed gold nanoparticles bearing higher efficiency (kinetic rate) against remediation of hazardous nitro dye (4‐nitrophenol), into safer amino (4‐aminophenol) analogues.