Extended Surface Area Research Articles

Signal amplification platform based on 2D MOF-on-MOF architectures-derived Co-decorated carbon@nitrogen-doped porous carbon for enhanced electrochemical acetaminophen sensing

Two-dimensional (2D) carbon-carbon hybrids derived from metal-organic frameworks (MOFs) are regarded as an intriguing type of electrode material in electrochemical sensing. In this work, a Co-decorated carbon@nitrogen-doped porous carbon heterostructure (Co/C@NC) was prepared via the simple calcination of 2D ZIF-L(Co)@ZIF-8. In this MOF-on-MOF precursor, the outer ZIF-8 layer not only prevents the collapse of ZIF-L(Co) during calcination but also endows the outer carbon an extended surface area and porous structure for more accessible active sites and a fast mass transfer process. Meanwhile, the formed CoNPs could facilitate the generation of graphitic carbon layers, which enhances electrocatalytic activity and boosted conductivity. Owing to these merits, the Co/C@NC-based sensor displays high electrochemical activity for acetaminophen (APAP) detection with a wide linear range (4 × 10-7 - 2 × 10-4 M) and a lower detection limit (8.2 × 10-8 M). The constructed sensor has been utilized for the analysis of APAP in real samples, yielding acceptable recovery between 96.6% and 104.0%. This work presents an efficient and convenient method for designing MOF-on-MOF-derived 2D carbon-carbon hybrids, which hold a promising prospect in electrochemical analysis.

Theoretical investigation of cobalt cluster size on adsorption kinetics in Fischer-Tropsch synthesis

In this study, the particles of cobalt with different sizes were simulated by Materials Studio software then the adsorption of H2, CO, and CH4 and its components (CH, CH2, CH3) as Fischer-Tropsch synthesis monomers were investigated using Density-functional theory. The results showed that the suitable sites for the adsorption of CO, H2 and monomers in Fischer-Tropsch synthesis are affected by the size of cobalt clusters. Increasing in the size of the cobalt cluster, the number of suitable sites for adsorption of the species decreases. In general, H2 adsorption energy decreases with increasing cobalt cluster size because larger clusters tend to have a less reactive surface due to increased coordination number and reduced surface charge density. On the other hand, CO adsorption energy tends to increase with cluster size because the larger clusters can accommodate the linear CO molecule more effectively due to their extended surface area. With considering the deformation of adsorbed species, Mulliken charge result, density of states and partial density of states, it could be stated that all species were chemically adsorbed on the surface of clusters, except CH4 that was adsorbed on Co-10 and Co-18 clusters is physically. Kinetic parameters for H2 and CO adsorption were calculated considering the change in cobalt cluster size.

Hierarchical nanoflowers of Bi/Fe-based selenide as a bifunctional electrocatalyst for alkaline water electrolysis

The current study presents a freestanding bifunctional electrocatalyst comprising hierarchically assembled Bi/Fe-based selenide with a nanoflower-like morphology on Ni foam for water electrolysis application. The impact of systematically adding Fe ions to Bi2Se3 on the phase and morphology is elaborately discussed. It is shown that tuning the Bi/Fe molar ratio governs the phase, electronic bandgap, and morphology, driven by the evolution of hetero-interfacial chemistry. The existence of multivalent metal ions, lattice defects, and an extended surface area remarkably improves the electrocatalytic activity. The optimized nanoflower-like composite electrode (1Bi1Fe-Se@NF) exhibits robust electrocatalytic efficacy with extremely low overpotentials of ∼53 mV and ∼230 mV at 10 mA cm−2 for hydrogen and oxygen evolution reactions, respectively. The symmetrical alkaline electrolyser, utilizing 1Bi1Fe-Se@NF electrodes (+,−), operates at a cell voltage of ∼1.52 V at 10 mA cm−2, lower than the device equipped with commercial Pt/C@NF (-) and RuO2@NF (+) (∼1.57 V). Even after 100 h of operation at 50 mA cm−2, the symmetrical cell maintains a stable voltage, highlighting the outstanding bifunctional catalytic activities of noble metal-free 1Bi1Fe-Se@NF for overall water electrolysis.

Supernanoporous SnO2 particles and spheres as sustainable solar cell constituents

This study presents the synthesis and a comparative report of the properties of supernanoporous SnO2 particles SNSP (0D) supernanoporous SnO2 spheres SNSS (3D) formed with an assembly of SNSP with a view to examine their application as effectual photoanodes in sustainable solar energy conversion. Porosity imposed nanoparticles with extended surface area improve photon interaction and charge transfer by increasing the absorption of light, hence addressing the existing efficiency hurdles in solar cells. SNSP with particle size of ∼23 nm and SNSS with particle size and sphere size of ∼26 nm and ∼800 nm, respectively, were synthesized by treating SnCl4 via solvothermal process at different experimental conditions. Important aspects of the as-synthesized SNSP and SNSS samples, such as the crystal structure, particle size, optical behaviour, identification of elements present, were characterized by powder X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Ultra Violet Diffuse Reflectance Spectroscopy (UV-DRS) and Energy Dispersive Analysis X-ray (EDAX) Spectroscopy techniques. Field dependent dark and photoconductivity studies reveal significant rise in the photoconducting nature, opto-electrical and surface properties of SNSP and SNSS. Pore size distribution and specific surface area of SnO2 particles and spheres were measured by Brunauer-Emmett-Teller (BET) analysis. High Resolution Transmission Electron Microscopy (HRTEM) is performed to analyze the size and shape of the porous SnO2 particles and spheres and further to correlate the data derived from FESEM. From other prevailing applications of porosity imposed nanomaterials such as gas sensing, catalytic and photodegradation the innovation of this work is to depict the novelty of porous SnO2 particle and sphere with highlighting thermal stability to instigate into the charge transport property suitable for solar cell application. The results were analyzed evincing the photovoltaic properties of spheres over particles and hence the PSC constituent among SNSP and SNSS with better proficiency was identified as appropriate photoconducting medium for fabrication of sustainable photovoltaic cells.

Unveiling the Potential of Covalent Organic Frameworks for Energy Storage: Developments, Challenges, and Future Prospects

AbstractCovalent organic frameworks (COFs) are porous structures emerging as promising electrode materials due to their high structural diversity, controlled and wide pore network, and amenability to chemical modifications. COFs are solely composed of periodically arranged organic molecules, resulting in lightweight materials. Their inherent properties, such as extended surface area and diverse framework topologies, along with their high proclivity to chemical modification, have positioned COFs as sophisticated materials in the realm of electrochemical energy storage (EES). The modular structure of COFs facilitates the integration of key functions such as redox‐active moieties, fast charge diffusion channels, composite formation with conductive counterparts, and highly porous network for accommodating charged energy carriers, which can significantly enhance their electrochemical performance. However, ascribing intricate porosity and redox‐active functionalities to a single COF structure, while maintaining long‐term electrochemical stability, is challenging. Efforts to overcome these hurdles embrace strategies such as the implementation of reversible linkages for structural flexibility, stimuli‐responsive functionalities, and incorporating chemical groups to promote the formation of COF heterostructures. This review focuses on the recent progress of COFs in EES devices, such as batteries and supercapacitors, through a meticulous exploration of the latest strategies aimed at optimizing COFs as advanced electrodes in future EES technologies.

Cyanide-Isolated Cobalt Catalyst for Ultraefficient Advanced Oxidation Treatment.

Catalyst design with a "Co-N-C" structure at the atomic level has shown great interest for peroxymonosulfate (PMS) activation toward advanced oxidation water treatment. Here, we present an innovative way of producing cobalt hexacyanocobaltate (Co-HCC) with an abundance of atomically isolated CoII-NC sites at the outer surface. This material allows ultraefficient PMS activation to generate plenty of sulfate and hydroxyl radicals, with a turnover frequency much higher than those of most cobalt-based catalysts reported so far and even the homogeneous catalysis by Co2+ ions. We gained fundamental insights on its unprecedently high catalytic performance based on experimental results and computational study. Then, we controlled the growth of Co-HCC on a ceramic membrane to form a confined oxidation environment that utilizes the extended surface area and maximal exposure of short-lived radicals for a fast removal of organic pollutants that enter the pores. As a result, this catalytic membrane achieves complete disruption of micropollutants under a water flux up to 10,000 LMH (merely 0.2 s retention time) and further >90% mineralization of organic pollutants in complex industrial wastewater matrices (<100 s retention time), together with the merits of operational simplicity and great longevity (2 weeks continuous run). Our study elicits a new milestone in "Co-N-C" catalyst structure design for PMS activation and highlights the great interest of producing catalytic membranes for a confined treatment of organic pollutants from partial oxidation to complete mineralization as a new benchmark.

Bio-inspired wettability patterning for flexible and wearable electrochemical immunosensors utilizing PDMS-TiO2 coating

The electrochemical sensor strip presented in this work, designed for low-volume point-of-care immunosensing applications and demonstrated using prostate-specific antigen as an example, exhibits remarkable efficiency by requiring only around 2 μL of sample volume. The decrease in sample amount required is facilitated through the application of nature inspired wettability patterning technique using PDMS-TiO2 nanocomposite coating, which incorporates distinct super-hydrophilic and super-hydrophobic regions on the electrode surface. This surface modification facilitates a highly sensitive antigen detection in minimal sample volumes. The sensor strip demonstrates a linear detection range spanning from 0.0001 to 100 ng mL-1, with a limit of detection of 0.0001 ng mL-1. Additionally, the sensor performance remains consistent across varying inclinations of the sensor strip, ensuring its applicability in the field of wearable sensing. Moreover, the incorporation of the PDMS-TiO2 coating enhances the electrochemical performance of the sensor by providing an extended surface area without introducing electrical interference. A wide range of electrochemical methods, such as cyclic voltammetry, linear sweep voltammetry, chronoamperometry, and electrochemical impedance spectroscopy, have been utilized. In support of these experimental findings, simulation studies have explored droplet spreading dynamics upon variation of the droplet size and electrode surface inclination. The developed sensor strip can serve as a promising candidate for practical point-of-care testing applications, expanding its applicability to a broad spectrum of immunosensing applications targeting diverse antigens.

New pressure drop and heat transfer correlations for turbulent forced convection in internally channeled tube heat exchanger ducts

In our previous paper, a novel heat exchanger concept, the so-called internally channeled tube (ICT) was suggested, based on a tubular geometry fitted with specially designed curved channels along the tube length. The enhanced heat transfer in the ICT results from extended surface area between two contacting fluids. To facilitate industrial application, ICT design methods must be developed. This work provides new equations for thermo-hydraulic characterization of ICT under turbulent flow conditions. In particular, new friction factor and Nusselt number correlations are derived based on the validated CFD simulations performed over a wide range of Reynolds numbers and geometrical parameters.

Chromophore appended DPA-based copper(II) complexes with a diimine motif towards DNA binding and fragmentation studies.

Mixed ligand copper(II) complexes [Cu(L1)(bpy)](ClO4)21 and [Cu(L2)(bpy)](ClO4)22 (where L1 = 1-(anthracen-9-yl)-N,N-bis(pyridin-2-ylmethyl)methanamine, L2 = 1-(pyren-1-yl)-N,N-bis(pyridin-2-ylmethyl)methanamine and bpy = 2,2'-bipyridine) were synthesised and characterised thoroughly via different analytical and spectroscopic techniques i.e., UV-vis spectroscopy, fluorescence spectroscopy, FT-IR spectroscopy, HRMS and EPR spectroscopy. The molecular structures of the synthesised complexes were obtained using the single-crystal X-ray diffraction technique. Both complexes exhibited penta-coordinated and acquired distorted square pyramidal geometry. The redox behaviour of complexes 1 and 2 was investigated by employing cyclic voltammetry. The DNA binding study was carried out by UV-vis spectrophotometry using double-stranded salmon sperm DNA (ds-ss-DNA). The binding constant (Kb) values of 1 and 2 were 0.11 × 104 M-1 and 1.05 × 104 M-1, respectively, which indicates that 2 has better binding ability than 1. This might be due to the higher conjugative abilities with the extended surface area of the aromatic pyrene ring compared to the anthracene moiety. The fluorescence quenching experiments were also performed with EB bound DNA (EB-DNA) and Stern-Volmer constant (KSV) values were calculated as 1.23 × 105 M-1 and 1.39 × 105 M-1 for 1 and 2, respectively, suggesting that 2 showed stronger interaction with ss-DNA than 1. The molecular docking data support the DNA-binding studies, with the sites and mode of interactions against B-DNA varying with 1 and 2. Evaluation of the DNA binding properties of the complexes to linearized plasmid DNA indicated that 2 had modest DNA binding properties, which is a pre-requisite for a genotoxic agent. The effect of 1 and 2 on cell survival was analysed using HeLa cells by MTT assay and it was observed that the IC50 values of 1 and 2 were 43.7 μM and 18.6 μM, respectively. Our study paves the way for the designing of bio-inspired novel mixed metal complexes, which shows promising results for further exploration of molecular and mechanistic studies towards the development of non-platinum based economical metallodrugs.

Effects of self-cleaning technique and nanofluid cooling on performance of photovoltaic solar unit employing sinusoidal surfaces

The urgent need for electricity generation for both commercial and residential uses can be satisfied by photovoltaic units, but the serious flaws of these units arise from the negative effects of environmental factors like dust, shadow, radiation, and wind on their performance. The present study examines how PV panels operate under dusty conditions, using ANSYS FLUENT software and focusing on steady-state and laminar conditions. This study aims to numerically examine a three-dimensional (3-D) photovoltaic thermal (PV-T) unit with sinusoidal walls (PV-T-SW). The testing fluids examined in current paper are Al2O3-H2O nanofluid and H2O. Under the same initial and boundary conditions, three configurations were tested: a PV module, a straight channel PV-T unit, and the PV-T-SW, which are numerically compared and examined. An important element that declines the power generation efficiency is the deposition of dust on photovoltaic panels. The key novelty of the current study is that it provides a numerical modeling of the impact of dust in the presence and absence of a self-cleaning coating on a photovoltaic thermal system, as well as the optimal cooling mode and configuration. First, suitable temperature management systems are critical for achieving high-efficiency solar photovoltaics, and in heat exchange devices, the employment of corrugated structures has proven to be a helpful strategy because of the benefits of extended surface area. Finally, the electrical (ηele) and thermal (ηth) efficiency are assessed by taking into account the optical properties of dust deposition and hydrophobic coating. The factors evaluated are the impacts of varying nanofluid concentration, inlet flow Reynolds number (ranging from 500 to 1500), wavy channel amplitude, and wavelengths on cooling performance. The findings revealed that using 4 % water-aluminum oxide as an operating fluid instead of H2O improved the coefficients of heat transfer in the channel by 15.7 %. In addition, at the next step, when water-aluminum oxide was used as a coolant and the sinusoidal channel was examined with different geometrical characteristics, it was discovered that the 9 mm wavelength and 0.8 mm amplitude channel, in comparison to the simple form of the system, had superior heat transfer performance. Furthermore, the obtained data indicate that the ηele decreased by 40 % as the dust deposition happens, and it was discovered that the coating reduced that negative effect on the glass used to cover solar cells. Because of rising environmental issues and the expense of energy, thermal control of sources of energy that are renewable is becoming more and more important. The findings of this investigation can be used for future PV cooling innovation unit development and optimization.

Assessment of single- and dual-PUF-containing passive air samplers for the collection of atmospheric PAHs

In this study, atmospheric polycyclic aromatic hydrocarbons (PAHs) were determined in fifteen individual, consecutive sampling events conducted in a semi-urban area of Bursa between June 2021 and February 2022 using passive air samplers (PASs). In this study, PASs containing single and dual PUF disks were used simultaneously and side by side. The aim of this study was to compare the results obtained from PASs containing single and dual PUF disks in terms of mass and number of PAH compounds. To our knowledge, the use of PASs containing dual PUF disks was applied for the first time in the literature. Because of the extended surface area, dual PUFs containing PAS can sample and detect more atmospheric PAHs. PAH masses in both samplers had a decreasing relationship with temperature. During the sampling period, the total masses of PAHs (∑16 PAH) were calculated as 1058 ± 1042 ng (117–3380 ng) on single-PUF disks and 1930 ± 1749 ng (279–5640 ng) on dual-PUF disks. The ratio of the dual-PUF value to the single-PUF value for ∑16 PAH in the samples varied between 1.41 and 3.45 (1.99 ± 0.50). Moreover, when the single and dual PUF mass results were evaluated on a compound basis, high correlation results were obtained. The sampling characteristics of both samplers were interpreted with the effect of possible PAH sources. It was determined that both samplers were affected by the same sources in the region due to the high similarities in diagnostic ratios. The main sources of PAHs were primarily residential heating and vehicle emissions.

Augmented Catalytic Performance of PVA- Assisted Fe2O3 Nano Catalyst for Water Treatment Synthesized via Green Route

Abstract Metal oxides (MO) are widely preferred for removing various effluents from water and air; however due to poor utilization of visible light, the application of MO nanoparticles for water treatments is hindered. This work reports the synthesis of ring-structured PVA-assisted Fe2O3 (P-Fe2O3) nanocomposite through a green route synthesis, for the elimination of methylene blue via sunlight triggered photocatalyst. FTIR spectroscopy confirmed the presence of desired functional groups in novel ring-structured Fe2O3 and PVA-assisted Fe2O3 (P-Fe2O3) nanocomposite. The crystallinity of Fe2O3 was also studied through XRD. Surface topography of Fe2O3 was examined through FE-SEM, that reveals a central hole with extended surface area of Fe2O3. UV-vis-spectroscopy is used to evaluate photocatalytic efficiency which shows, pristine Fe2O3 exhibited 37% degradation in stipulated time intervals of 30~120 mins. The photocatalytic efficiency of augmented P-Fe2O3 nanocomposite expelled 82% of the methylene blue in span of just 02 hours. The stability of the developed nanocomposite in the effluent medium was investigated through FTIR by observing the change in carboxyl adsorption band produced during degradation of PVA, that manifests the fact that no degradation was witnessed for PVA even after 120 min, that makes P-Fe2O3 a promising material for the degradation of AZO dyes.

One-pot decoration of CdS and CdMoO4 nanoparticles on g-C3N4 nanoplates: Boosted photocatalytic degradation of tetracycline

Photocatalytic water detoxification has been a hot-spot research field in recent years. In this regard, CdS and CdMoO4 nanoparticles were decorated on g-C3N4 nanoplates via a one-pot hydrothermal route. The morphology, structure, phase, surface properties, electrochemical, and optical properties of the resultant materials were identified by XRD, FT-IR, UV–vis DRS, FESEM, TEM, HRTEM, XPS, EDX, EIS, BET, BJH, and PL analyses. The optimum ternary nanocomposite exhibited boosted activity for degradation of tetracycline (TC), Congo red (CR), methylene blue (MB), methyl orange (MO), and malachite green (MG) upon visible light, which was 41.6, 29.0, 16.1, 27.4, and 38.2 times higher than pristine g-C3N4. The UV–vis DRS, EIS, PL, and BET analyses attributed the boosted activity to the generation of more charge carriers, promoted segregation and transfer of charges, and extended surface area. The quenching experiments confirmed the crucial role of holes and superoxide anion radicals in the degradation reaction. Eventually, based on the outcomes, a probable mechanism for the boosted photocatalytic ability was discussed.

Critical heat flux and heat transfer behaviors on aged RPV outer wall surface in flow boiling under IVR conditions

Critical Heat Flux (CHF) plays an important role in the nuclear power plant safety strategy both during normal operation and under accident conditions. During normal operation, the outside wall is exposed to high-temperature environment. The surface is oxidized by air, which is so-called “aged surface”. To specify the characteristics of aged surface and the effect on CHF, the specimen aging experiments and flow boiling experiments under External Reactor Vessel Cooling (ERVC) were conducted. The results of specimen aging experiments show that surface characteristics get steady after 500 h aging and the oxide layer is the Fe-Fe2O3-Fe3O4 mixture. After aging, the surface gets rougher and has better hydrophily. In the flow boiling experiments, characteristics of heat transfer and CHF are studied. Heat transfer is enhanced by extended surface area and increased nucleation sites at lower angle. The influence of capillary suction is not obvious and the enhancement of CHF is limited. As the inclination angle increases, the departure of bubbles is more frequent and capillary suction is dominant to assist liquid supply into the liquid sublayer and delay the boiling process. At higher angle, CHF is more obviously enhanced but heat transfer gets worse. Overall, CHF of RPV outer wall is increased after surface aging, and it is beneficial to improving the safety margin of IVR mitigation measures.

Myeloprotection with activated carbon in doxorubicin-treated rats

Chemotherapy can often cause a variety of side effects including bone marrow (BM) suppression, termed as myelosuppression. Accordingly, facile and effective management of chemotherapy-induced myelosuppression is currently a pivotal task for experimental pathologists and oncologists. Here, we chose to use activated carbon (AC) with an extensive surface area for studying its possible protective effectiveness with respect to BM in doxorubicin (DOX)-treated rats. Spherical AC with an extended surface area up to 4490 m2/g was prepared for per os (p/o) delivery, whereas for intraperitoneal (i/p) delivery we used the powdered form of AC that was derived from the aforementioned spherical AC. During the monthly treatment of animals with AC and DOX these two components were delivered alternately (not in the same day). After treatment, BM cells were isolated from femurs of sacrificed animals, stained with acridine orange (AO) and analyzed by flow cytometry. Regardless of the route of AC delivery (p/o or i/p), apparent myeloprotection with a possible regenerative effect was observed in animals that received DOX, as evidenced by recovery of the populations of total nucleated cells (TNC) and polychromatic (immature) erythrocytes accompanied by a considerable reduction of the number of apoptotic/dead cells among TNC (≤2.0%). Moreover, as a result of AC administrations, there was a significant increase of AO green and far-red fluorescence intensities in the population of TNC, which is suggestive of the ongoing quantitative and conformational changes in DNA and RNA associated with cell recovery and proliferation. Thus, AC preparations under the present experimental conditions can effectively tackle DOX-induced myelosuppression via mechanisms not necessarily associated with adsorptive detoxification.

S-scheme CeO2-x/AgFeO2/Ag photocatalysts with impressive activity in degradation of different antibiotics under visible light

In the recent decades, along with human consumption, antibiotics are widely used in animal feed to prevent and treat infectious diseases in livestock. Accordingly, to eliminate these compounds, the developing photocatalytic systems based on visible-light exposure can be a step forward. In the present study, CeO2 with oxygen vacancies (CeO2-x) was utilized for the facile fabrication of plasmonic CeO2-x/Ag/AgFeO2 photocatalysts. Interestingly, photocatalytic activity of CeO2-x/Ag/AgFeO2 (20%) nanocomposite in degradation of tetracycline hydrochloride, azithromycin, metronidazole, and cephalexin was promoted 55.7, 49.1, 76.2, and 71.5-folds as much as CeO2 and 10.2, 10.5, 21.1, and 47.6-folds in comparison with CeO2-x, respectively. The surface area of CeO2-x/Ag/AgFeO2 (20%) photocatalyst was enhanced 4.41 times compared to the pristine CeO2. Moreover, the band gaps of CeO2-x and CeO2-x/Ag/AgFeO2 (20%) were 2.69 and 1.90 eV, respectively. The impressive activity was ascribed to the production of a large number of electron/hole pairs, facile segregation and transfer of charges, and extended surface area. Finally, the fabricated plasmonic CeO2-x/Ag/AgFeO2 (20%) photocatalyst retained most of its activity after five photocatalytic runs.

Influence of extended surface area of heatsink on heat transfer: design and analysis

PurposeLight emitting diode (LED) has been the best resource for commercial and industrial lighting applications. However, thermal management in high power LEDs is a major challenge in which the thermal resistance (Rth) and rise in junction temperature (TJ) are critical parameters. The purpose of this work is to evaluate the Rth and Tj of the LED attached with the modified heat transfer area of the heatsink to improve thermal management.Design/methodology/approachThis paper deals with the design of metal substrate for heatsink applications where the surface area of the heatsink is modified. Numerical simulation on heat distribution proved the influence of the design aspects and surface area of heatsink.FindingsTJ was low for outward step design when compared to flat heatsink design (ΔT ∼ 38°C) because of increase in surface area from 1,550 mm2 (flat) to 3,076 mm2 (outward step). On comparison with inward step geometry, the TJ value was low for outward step configuration (ΔTJ ∼ 6.6°C), which is because of efficient heat transfer mechanism with outward step design. The observed results showed that outward step design performs well for LED testing by reducing both Rth and TJ for different driving currents.Originality/valueThis work is authors’ own design and also has the originality for the targeted application. To the best of the authors’ knowledge, the proposed design has not been tried before in the electronic or LED applications.

Experimental and simulation approach of cooling system in 3-phase inverter using extended surface

Overheating is a failure mode that significantly affects the reliability of electronic devices. All electronic devices, including a 3-phase inverter driving a traction motor, produce heat dissipation. Heat dissipation needs to be controlled with cooling to prevent overheating. Overheating can be avoided by increasing cooling or reducing heat dissipation. Heat dissipation in the 3-phase inverter is caused by the internal resistance of the metal–oxide–semiconductor field-effect transistor (MOSFET), switching loss, and other factors. Cooling for the 3-phase inverter can use water coolant or air coolant. The cooling system is based on the amount of heat dissipation produced. Cooling of a 3-phase inverter can use air coolant with the addition of an extended surface area in the heat sink. The heat sink uses aluminum material, often called pin fin. There are kinds of aluminum available in the market. We calculated heat generation based on the MOSFET's internal resistance, switching loss, and other factors. We validated the simulation results experimentally using a thermal camera. Thus, we could find an optimal number, dimensions, and aluminum type of fin for the cooling system in the 3-phase inverter.

Force Sensor Chip With High Lateral Resolution for Artificial Skin and Surgical Applications

The growing interest in artificial skin-based tactile systems requires sufficiently accurate, stretchable, low-power mechanical sensors. In this study, we present a novel capacitive device and an evaluation method capable of retrieving the force vector and determining the position of the loading point on an extended area without the application of a large matrix of individual sensors. With this tool, we can simultaneously increase the extractable information from an extended surface area and reduce the complexity, thereby the power consumption of the system. Thus, an alternative path is opened toward robotic tactile sensing by using a small array of sensors but covering a relatively large receptive field. Even a single sensor can meet the requirements of specific devices—for example, in catheters—to detect tissue hardness, bending, or narrowing of the arteries or veins. Apart from the medical and robotic applications, the flexibility in processing the Flex2Rigid platform enables the mimicry of human fingers or hands with integrated sensors and driving circuits.

Polymerization-Pyrolysis Assisted Construction of Multiscale Porous Carbon for High-Performance Supercapacitors

High energy density combined with rapid mass transport is highly desired for carbon-based electrical double-layer capacitors. Here, multiscale porous carbon has been constructed by an efficient polymerization-pyrolysis strategy. The resorcinol-formaldehyde polymer anchored with Fe3+ is firstly prepared, and the in situ formed Fe3O4 nanoparticles act as mesoporous template during the pyrolysis process. The resultant hierarchically porous carbon achieves an extended surface area of 2260.3 m2 g−1 and wide pore size distributions including micro-, meso-, and macropores. The synergism of large surface area, high conductivity, and interconnected ion transport channels leads to superior energy storage performances of prepared multiscale porous carbon electrode. It delivers a high specific capacitance of 271.7 F g−1 at 0.5 A g−1 in KOH electrolyte, accompanied with a prominent capacitance retention of 88.5% when the current density is 10.0 A g−1. Besides, the assembled symmetric supercapacitor using organic electrolyte exhibits a maximum energy density of 54.0 Wh kg−1 at the power density of 750.0 W kg−1, as well as the superior cyclic stability with a capacitance retention of 88.2% after 10000 cycles.