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This study was systematically conducted to investigate the dependence of mechanical behaviors of double-lap bi-material joints on various environmental conditions, including room temperature dry (R...

The development of biosorbents using carbon–neutral materials is expected to contribute to a sustainable environment in water purification. In this study, the biochar-alginate composite was selected as the core material of biosorbent and Cu(II) was set as the adsorption experimental model. In particular, in order to improve the insufficient mechanical strength of alginate, a melamine sponge (MS) was applied as a support to the biochar-alginate composite. As a result, the tensile strength was significantly improved about 4.3-fold compared to the alginate foam (without MS), and it can be manufactured in the shape required in the process. The Cu(II) adsorption capacity of the biosorbent was analyzed based on the adsorption equilibrium and kinetics. As a result, the pseudo-second-order model and the Langmuir isotherm model were most suitable, and the maximum adsorption capacity of Cu(II) was estimated to be 126.58 mg/g. In conclusion, the biochar-alginate composite on melamine sponge was an excellent material as a biosorbent for removing Cu(II) from wastewater.

This paper presents details of the mechanical properties related to the static and fatigue strength of carbon fiber reinforced polyetherketoneketone (CF/PEKK) thermoplastic induction-welded composite joints. To better understand the process parameters, the finite element modeling (FEM) of the heat distribution was analyzed based on the generator power, coil coupling distance, coil moving speed, frequency, compaction force, and coil geometry while maintaining the optimal coil speed. The temperature behavior calculated using the simulation model exhibited good agreement with experimental results. A microscopic inspection, non-destructive test (NDT) was conducted to check the morphology characteristics of the welded joints. To check the mechanical performance of the induction-welded specimens, single-lap shear strength (SLSS) tests under static and cyclical fatigue loading conditions were conducted to check the weld qualities from a practical perspective. The mechanical testing results indicated that the static and cyclical fatigue specimens were dominated by a cohesive failure mode with a light fiber tear (LFT). These results suggested that using the optimal process parameters based on multi-physics FEM simulation could potentially improve mechanical performance.

Lipid-bilayer nanodiscs (NDs) wrapped in membrane scaffold proteins (MSPs) have primarily been used to study membrane proteins of interest in a physiological environment. Recently, NDs have been employed in broader applications including drug delivery, cancer immunotherapy, bio-imaging, and therapeutic virucides. Here, we developed a method to synthesize a dimeric nanodisc, whose MSPs are circularly end-spliced, with long-term thermal stability and resistance to aggregation. The end-spliced nanodiscs (esNDs) were assembled using MSPs that were self-circularized inside the cytoplasm ofEscherichia colivia highly efficient protein trans-splicing. The esNDs demonstrated a consistent size and 4-5-fold higher stability against heat and aggregation than conventional NDs. Moreover, cysteine residues on trans-spliced circularized MSPs allowed us to modulate the formation of either monomeric nanodiscs (essNDs) or dimeric nanodiscs (esdNDs) by controlling the oxidation/reduction conditions and lipid-to-protein ratios. When the esdNDs were used to prepare an antiviral nanoperforator that induced the disruption of the viral membrane upon contact, antiviral activity was dramatically increased, suggesting that the dimerization of nanodiscs led to cooperativity between linked nanodiscs. We expect that controllable structures, long-term stability, and aggregation resistance of esNDs will aid the development of novel versatile membrane-mimetic nanomaterials with flexible designs and improved therapeutic efficacy.

Delamination failure commonly appears in composite structures, especially those with curved regions, where a relatively high through-thickness stress is generally created. This study examined the d...

Magnesium and its alloys are used in many applications due to their high strength-to-weight ratios. The poor formability which is caused by lack of available slip systems and the existence of twinning has been the major hindrance in expanding their usage to other new applications. In order to improve the formability of magnesium and its alloys, it is critical to understand the characteristics of the available slip and twin systems and the interactions among them. The slip activities occur due to dislocation motions, and twinning and dislocation motions interact with each other in order to reduce the overall plastic dissipation energy in deformation. Since the complex interaction hardening among slip and twin modes is not automatically realized by conventional standard CP (crystal plasticity) theories, additional measures must be included in the crystal plasticity constitutive theory to accurately represent the mechanical behavior of magnesium and its alloys. This paper takes into account interaction hardening among slip and twin modes by employing an interaction hardening model based on a physical property (saturation strength), which reduces trials and errors significantly in the stress–strain data fitting process. Taking into account elastic anisotropy, a twinning CP theory is proposed and an implicit time integration scheme for the proposed anisotropic elasticity twinning CP theory is derived in this study. The derived CP theory and the implicit time integration scheme are implemented into a large deformation FE code, and the single crystal channel-die compression tests and polycrystal uniaxial tension/compression tests of magnesium done in [1] are successfully reproduced by simulations. Using the anisotropic elasticity twinning CP FE code, the effects of strong elastic anisotropy on the convergence and stability of CP FE codes are investigated. Strong elastic anisotropy turns out to lower the stability and accuracy of CP FE codes, and the proposed implicit time integration scheme successfully overcomes these difficulties caused by strong elastic anisotropy.

Quaternary nanorod-type BaInSbSe5 semiconductor combined graphene-based conducting polymer (PPy) (BaInSbSe5-G-PPy, BNSGP) nanocomposites were prepared using a facile hydrothermal method. BNSGP nanocomposites were used to make up gas sensors to detect H2O2 and H2S at standard temperature condition. Morphologies, shape, and structures of BNSGP were specified by X-ray diffractometer (XRD), Scanning Electron Microscopy (SEM), Energy-dispersive X-ray elemental analyzer (EDX), transmission electron microscopy (TEM), high-resolution TEM (HRTEM) technique, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and diffuse reflectance spectroscopy (DRS). When examined with H2O2 and H2S concentrations as low as 10 ppb, the gas sensor using BNSGP nanocomposites showed a good reactivity and sensitivity of 1.25 V/K with real-time response/recovery effects of 234 and 76 s, respectively. It also showed a conspicuously high selectivity for H2O2 and H2S. However, it only showed insignificant response to any other reactance gases such as HCl, CH3OH, and C2H5OH. Its performance as a H2O2 and H2S sensor was estimated by CV meter (cyclic voltammeter). The fabricated sensor for H2O2 and H2S showed an extensive linear selectivity from 300 to 90 ppm with a low detection range of 300 ppm.

Knowing a material’s true stress-strain curve is essential for performing a nonlinear finite element analysis to solve an elastoplastic problem. This study presents a simple methodology to determine the true stress-strain curve of type 304 and 316 austenitic stainless steels in the full range of strain from a typical tensile test. Before necking, the true stress and strain values are directly converted from engineering stress and strain data, respectively. After necking, a true stress-strain equation is determined by iteratively conducting finite element analysis using three pieces of information at the necking and the fracture points. The Hockett-Sherby equation is proposed as an optimal stress-strain model in a non-uniform deformation region. The application to the stainless steel under different temperatures and loading conditions verifies that the strain hardening behavior of the material is adequately described by the determined equation, and the estimated engineering stress-strain curves are in good agreement with those of experiments. The presented method is intrinsically simple to use and reduces iterations because it does not require much experimental effort and adopts the approach of determining the stress-strain equation instead of correcting the individual stress at each strain point.

Densification in glassy networks has traditionally been described in terms of short-range structures, such as how atoms are coordinated and how the coordination polyhedron is linked in the second coordination environment. While changes in medium-range structures beyond the second coordination shells may play an important role, experimental verification of the densification beyond short-range structures is among the remaining challenges in the physical sciences. Here, a correlation NMR experiment for prototypical borate glasses under compression up to 9 GPa offers insights into the pressure-induced evolution of proximity among cations on a medium-range scale. Whereas amorphous networks at ambient pressure may favor the formation of medium-range clusters consisting primarily of similar coordination species, such segregation between distinct coordination environments tends to decrease with increasing pressure, promoting a more homogeneous distribution of dissimilar structural units. Together with an increase in the average coordination number, densification of glass accompanies a preferential rearrangement toward a random distribution, which may increase the configurational entropy. The results highlight the direct link between the pressure-induced increase in medium-range disorder and the densification of glasses under extreme compression.

Microelectronic devices (MEDs) that utilize functionalized single-walled carbon nanotubes (SWCNTs) for hydrazine (HZ) sensing applications were developed and investigated, demonstrating their selec...

Fuel-flexible aircraft propulsion systems using compression ignition engines will require novel strategies for reducing the ignition delay of low-reactivity fuels to feasible timescales. Hot surface ignition of fuel sprays has been implemented in some practical situations, but the complex nature of flame formation within the spray structure poses significant challenges. In order to design next-generation ignition devices, the capacity of hot surface heating elements to promote fuel spray ignition must be investigated. In this study, a rapid compression machine (RCM) was used to examine the ignition process of a single kerosene-based F-24 jet fuel spray with a cylindrical heating element inserted into the spray periphery. The experiments, performed with moderately high injection pressures of 40 MPa, have demonstrated two modes of ignition governed by surface temperature and insertion depth of the heating element. There exists an optimal position where the heating element tip is located in the fuel vapor cone around the liquid spray. For this configuration, a critical surface temperature was identified (∼1250 K), above which short ignition delays associated with a “spray ignition” mode are consistently achieved. In this case, a local ignition flame kernel propagates downstream to the flame lift-off length before full ignition of the spray. In comparison, below the critical temperature a slower “volumetric” mode results. The extended ignition delays associated with this mode may be impractical for compression ignition engines operating at high speeds and increased altitude.

Influenza, one of the most contagious and infectious diseases, is predominantly transmitted through aerosols, leading to the development of filter-based protective equipment. Though the currently available filters are effective at removing submicron-sized particulates, filter materials with enhanced virus-capture efficiency are still in demand. Coating or chemically modifying filters with molecules capable of binding influenza viruses has received attention as a promising approach for the production of virus-capturing filters. For this purpose, tannic acid (TA), a plant-derived polyphenol, is a promising molecule for filter functionalization because of its antiviral activities and ability to serve as a cost-efficient adhesive for various materials. This study demonstrates the facile preparation of TA-functionalized high-efficiency particulate air (HEPA) filter materials and their efficiency in influenza virus capture. Polypropylene HEPA filter fabrics were coated with TA via a dipping/washing process. The TA-functionalized HEPA filter (TA-HF) exhibits a high in-solution virus capture efficiency of up to 2,723 pfu/mm2 within 10 min, which is almost two orders of magnitude higher than that of non-functionalized filters. This result suggests that the TA-HF is a potent anti-influenza filter that can be used in protective equipment to prevent the spread of pathogenic viruses.

During nearly 2 centuries of history in graphene researches, numerous researches were reported to synthesize graphene oxide (GO) and build a proper graphene assembly. However, tons of research prevail without verifying the reproducibility of GO that can be sensitively attributed by the graphite nature, and chemical processes. Here, the structure and chemistry of GO products were analyzed by considering parent graphite sources, and three different oxidation methods based on Hummer's method and the addition of H3PO4. The oxidation level of GO was characterized by monitoring the C/O and sp2 carbon ratio from X-ray photoelectroscopy (XPS) spectra. It was observed that the oxidant intercalation behavior was dependent on the morphological differences of graphite; synthetic and natural flake graphite were compared based on their origins in shape and size from different suppliers. Thermal reduction and exfoliation were applied to GO powders to prepare thermally expanded graphene oxide (TEGO) as a graphene assembly. Gas releases from the reduction of oxygen functional groups split layered GO structure and build a porous structure that varied specific surface area regarding oxidation degrees of GO.

This paper reports the facile synthesis and characterization of carbon supported Pd nanowires with low Ru contents (nRuPd/C). An anti-galvanic replacement reaction involving the reduction of Ru(iii) ions by nanoporous Pd nanowires to form nRuPd alloy nanowires was observed. A series of nRuPd/C materials with various Ru/Pd ratios were prepared by the spontaneous deposition of a Ru cluster on a Pd nanowire core using different Ru precursor concentrations (RuCl

The effects of blending ratio on mixtures of an alcohol-to-jet (ATJ) fuel and a conventional petroleum-derived fuel on first stage ignition and overall ignition delay are examined at engine-relevant ambient conditions. Experiments are conducted in a high-temperature pressure vessel that maintains a small flow of dry air at the desired temperature (825 K and 900 K) and pressure (6 MPa and 9 MPa) for fuel injections from a custom single-hole, axially-oriented injector, representing medium (7.5 mg) and high (10 mg) engine loading. Formaldehyde, imaged using planar laser-induced fluorescence, is measured at discrete time steps throughout the first and second stage ignition process and is used as a marker of unburned short-chain hydrocarbons formed after the initial breakdown of the fuel. The formaldehyde images are used to calculate the first stage ignition delay for each ambient and fuel loading condition. Chemiluminescence imaging of excited hydroxyl radical at 75 kHz is used to determine the overall ignition delay. At all conditions, increased volume fraction of ATJ resulted in longer, but non-linearly increasing, overall ignition delay. Across all of the blends, first stage ignition delay accounted for about 15% of the increase in overall ignition delay compared to the military's aviation kerosene, F-24, which is Jet A with additives, while extended first stage ignition duration accounted for 85% of the increase. It is observed that blends consisting of 0–60% by volume of the low cetane number ATJ fuel produced nearly identical first stage ignition delays. These results will inform the development of ignition models that can capture the non-linear effects of fuel blending on ignition processes.

A highly crystalline pomegranate-like base-acid bifunctional beta zeolite was successfully synthesized by the steam-assisted crystallization method using a basic nitrided N-beta as the starting material. The secondary crystal growth of a beta zeolite generating acid functionality occurred over the outer surface and intercrystalline void spaces of the N-beta zeolite. The pomegranate-like N-beta@H-beta zeolite had a high surface area and base-acid dual functionality because of the well-connected framework topologies of the H-beta and N-beta crystallites. The N-beta@H-beta zeolite exhibited a superior yield of benzylidenemalononitrile during the tandem deacetalization-Knoevenagel condensation of benzaldehyde dimethyl acetal and malononitrile compared to H-beta, N-beta, and their physical mixture. This is likely due to the isolated and balanced activity of the base- and acid-catalyzed reactions.

In this study, we have developed a thin film adhesion evaluation system for diamond coating tool, which is mainly used for CFRP processing, which is widely used in aviation and automobile industries. Carbon fiber reinforced plastic (CFRP), which is a composite material is widely used for high efficiency and light weight in the aerospace industry and automobile industry. CFRP has a low specific gravity and a high specific strength. However, it has difficulty in processing because it has difficulty property. In order to cope with this problem, CFRP is processed using a diamond coating tool with a higher surface hardness. Because of the high surface hardness of the diamond coating tool, it is difficult to evaluate the adhesive strength of the tool, and it is difficult to quantitatively evaluate the existing adhesion force evaluation method and it is costly. This study has developed an evaluation method to measure the adhesive force based on the data of the grinding process using a low cost polishing pad. When the frictional force and the shearing force are applied to the specimen by the sanding belt, friction is continuously generated between the coating layer and the belt, and peeling occurs at the moment when a specific load is applied. Acceleration, load, and torque values that occur during each experiment are collected through acceleration sensors, load cells, and torque sensors. The data obtained through the experiments are subjected to FFT processing and analysis. As a result, the peeling point and the critical load value at this point are identified and referred to as the adhesion force of the coating layer.

Organic semiconductor (OSC)-based gas detection has attracted considerable attention due to the facile manufacturing process and effective contact with target chemicals at room temperature. However, OSCs intrinsically suffer from inferior sensing and recovery capability due to lack of functional sites and deep gas penetration into the film. Here, we describe an interpenetrating polymer semiconductor nanonetwork (IPSN) channel possessing unreacted silanol (Si-OH) groups on its surface to overcome bottlenecks that come from OSC-based chemodetection. On the top of the IPSN, moreover, we introduced electron-donating amine (NH2) groups as a chemical receptor because they strongly interact with the electron-withdrawing nature of NO2 gas. The NH2-IPSN-based field-effect transistor exhibited high-performance chemodetection such as ultrasensitivity (990% ppm-1 at 5 ppm) and excellent NO2 selectivity against other toxic gases. Impressively, the gas recovery was significantly improved because the NH2 chemical receptors anchored on the surface of the IPSN suppress deep gas penetration into the film. This work demonstrates that our NO2 chemodetection is expected to provide inspiration and guideline for realization of practical gas sensors in various industries and daily life.

A shield made of barium sulfate for interventional angiography was analyzed for X-ray spectrum transmission and radiation dose rate using an anthropomorphic phantom to evaluate radiation dose reduc...

Hexagonal close-packed (HCP) metals show highly anisotropic mechanical responses due to twinning, slip and the interaction among various slip and twin systems. Each HCP metal shows different sets of activated slip and twin systems. The interaction among slip and twin systems causes highly nonlinear and rapidly changing hardening behaviors in the critical resolved shear stress (CRSS) of each slip/twin system. To accurately understand the anisotropic mechanical response of HCP metals, both single-crystal and polycrystal tests must be performed. The interaction among different slip and twin systems shows different behaviors in the single-crystal and polycrystal settings since the interacting environments are different. The fitting process of the single crystal and polycrystal stress–strain data involves a series of trials and errors to find the correct interaction patterns among various slip and twin systems. The fitting procedures used in previous researches take a lot of times of trials and errors and are not guided by any physical property. Therefore, this study employs a recently proposed new fitting procedure, which is based on a physical property, the saturation strength of the material, to fit magnesium experimental data more efficiently with a less number of trials and errors. Compared to the slip process, twinning is computationally more difficult to take into account due to the directionality of the twin process, i.e., twinning occurs only in one direction, not in the opposite direction unlike the slip process. The rapidly changing highly nonlinear interaction hardening behaviors among various slip and twin systems are computationally challenging. Both of the above computational difficulties require a more robust and accurate numerical scheme than previously used ones to obtain accurate representations of experimental data. Therefore, this study proposes a more accurate and robust numerical scheme for the hardening strengths (CRSS) of twin/slip systems and interaction hardening. The newly proposed scheme is based upon implicit time integration, which enhances accuracy and stability. Using the proposed fitting procedure and the implicit integration scheme for hardening strength (CRSS) and interaction hardening, the experimental stress–strain data of polycrystal magnesium shown in Kelley and Hosford (The plastic deformation of magnesium. Technical report, 1967, Trans Metall Soc AIME 242:5–13, 1968) are successfully reproduced.

This paper presents an electromagnetic-mechanical repair patch (EMRP) to restore the mechanical and electromagnetic (EM) wave absorption performance of a radar-absorbing structure (RAS) damaged by lightning strike. Several researchers have primarily focused on ensuring high repair efficiency, particularly in terms of the primary load-bearing properties of repaired fiber-reinforced plastics. However, no study has proposed a practical repair approach that considers the multi-functionality of the radar-absorbing structure. The EMRP method can be used to repair lightning strike damage in a radar-absorbing structure with electroless nickel-plated glass fabric, considering the need to maintain structural integrity and electrical continuity to achieve a high repair efficiency. Damage due to an artificial lightning strike was assessed in terms of area and depth of the damage using image processing, ultrasonic C-scan, and micro X-ray inspection. The EM characteristics of one-dimensional return loss scanning and the echo radar-cross-section level were measured to verify the stealth performance of the repaired radar absorber in the X-band. In addition, the tensile test results demonstrated that the repaired radar absorber had a high recovery rate of 93% compared to the pristine radar absorber. The experimental results obtained in this study validate the use of the proposed EMRP method in repairing radar-absorbing structures.

Understanding ion intercalation at electrode--electrolyte interfaces is key to the development of energy storage and water desalination. In this work, we investigate the Li$^{+}$ kinetics at a prot...

Sulfonated poly(phenylene) oxide (sPPO) polymer is coated in a dopamine hydrochloride solution to prepare a highly durable, low-price polymer membrane for vanadium redox flow batteries (VRFBs). The polydopamine (PDA) coating on the sPPO membrane is confirmed using SEM and EDX analysis. sPPO coated with PDA exhibits decreased proton conductivity due to high resistance. However, VO+2 reducibility tests shows that the chemical stability is improved due to the introduction of the PDA coating layer on the sPPO membrane, which has a chemical structure with poor durability in VO+2 solution under the operating conditions of a VRFB. These results show that this polymer electrolyte membrane based on PDA-coated sPPO is a candidate for application in the long-term operation of VRFBs.

The yttria stabilized zirconia (YSZ) ceramic coating of feed rollers exposed to the high temperature environment used in the floating process for display panel glass manufacturing has high hardness, low porosity and no cracking in the high temperature environment. To obtain such properties, which are necessary for glass panel manufacture, analysis of various parameters such as powder particle size, plasma nozzle diameter, powder feeding rate, and coating distance, was carried out. The results demonstrated a hardness of about 800–1019 Hv 0.1, 150 % higher than the general YSZ coating film. It was possible to obtain a dense coated film with a porosity of 1.4 to 3.0 %, which is 50 % lower than the general porosity. The condition where no cracks occur after an 850 °C thermal shock was also found.

(K,Na)NbO3 (KNN) thin films are promising lead-free piezoelectric materials for microelectromechanical systems (MEMS) devices. However, the origin of the strong piezoelectric properties of KNN thin films remains unclear because crystallographic deformation by piezoelectric effects is not clear in detail. We used synchrotron X-ray diffraction (XRD) to explore the origin of the piezoelectricity of polycrystalline (K0.45Na0.55)NbO3 (KNN) thin films, which led to the observation of large crystal deformation originating from the piezoelectric effects. The peak shifts of the XRD patterns indicated changes in both the out-of-plane and in-plane lattice parameters of KNN. In addition, an electric field-induced phase transition under an applied electric field was observed. The microscopic piezoelectric coefficients (e31,f) were estimated from the in situ XRD results and subsequently compared with the macroscopic piezoelectric coefficients estimated from the converse piezoelectric effect by the cantilever method. The macroscopic |e31,f| coefficients based on the converse piezoelectric effect were in the range of 6.3–11.1 C/m2, whereas the microscopic |e31,f| values based on the in situ XRD results were in the range of 1.2–1.5 C/m2. However, the macroscopic piezoelectric coefficients from the direct piezoelectric effect were 1.6–2.0 C/m2, which were similar to those obtained from the in situ XRD results. The results suggest that the large macroscopic piezoelectric properties associated with the converse piezoelectric effect arise from the observed electric field-induced phase transition. This study demonstrates the main factors associated with the macroscopic piezoelectric properties in lead-free KNN thin films.

In this study, material performance was analyzed depending on the cooling method of concrete damaged by fire. Various non-destructive and destructive tests were conducted for material performance analysis. Further, the influence of cooling methods was assessed according to each test. As a result of the evaluation, it was confirmed that the residual performance of the concrete was significantly different according to the cooling method (air cooling and water cooling), and the performance difference according to the cooling method was also observed depending on the exposure temperature. Through this study, it was possible to understand the impact of water used in firefighting on fire-damaged RC structures, and it is deemed necessary to further study various concrete mixing models.

Orodispersible films (ODF) were prepared with mixtures of hyaluronic acid (HA) and carboxymethyl cellulose (CMC), and the effect of CMC addition on the disintegration and mechanical properties of the composite films were examined. Low molecular weight HA (10 kDa) appeared more acceptable for ODF than high molecular weight HA (800 kDa) because of its rapid disintegration in the oral cavity. The composite films appeared similar to pullulan film with excellent transparency and surface smoothness. The disintegration time as well as mechanical properties of the films such as tensile strength and elongation at break were increased by the addition of CMC. Overall, the CMC addition, up to 35%, improved the mechanical properties of low molecular weight HA film within a proper range of disintegration time for ODF.

A new multi-location soot sampling method is used to enhance the knowledge about the structural evolution of in-flame particles in a light-duty optical diesel engine. Through thermophoresis-based particle sampling performed at multiple in-bowl locations, the soot structures are shown for both early formation stage and later stage from the same combustion event. Three different jet-spacing angles of 45°, 90° and 180° were studied to analyse how different levels of jet–jet interaction impact the soot particle morphology and internal structure. One selected jet–jet interaction condition was further analysed to show differences in soot structures between the up-swirl side and down-swirl side of the wall jets. From transmission electron microscopes (TEM) images of the sampled soot particles and their statistical size analysis, it was found soot particles initially formed within 45∘ separated jet–jet interaction region have un-solidified premature aggregates due to limited carbonisation in the locally fuel-rich mixtures. When these soot particles travelled on the down-swirl side of the jets, they became solidified and carbonised while the oxidation was evident from the smaller soot primary particle and longer carbon-layer fringe and lower tortuosity. The higher mixing on the up-swirl side of the jets further enhanced the soot oxidation, resulting in even smaller soot primary particle, fragmentation of large soot aggregates, and even longer and less curved carbon-layer fringes. Regarding jet–jet interaction, the 180° jet spacing angle created no jet–jet interaction condition on the soot sampler locations. For smaller jet-spacing angles, the increase in jet–jet interaction promoted the soot formation as evidenced by larger and more complex soot aggregates formed due to more active soot aggregation and agglomeration. The soot oxidation became limited at higher jet–jet interaction conditions, which led to more amorphous soot internal structures.

In this paper, techniques for machining and micro-structuring dimples and grooves on the interior of cylinders using an active rotating tool are discussed. Microscopic dimples and grooves patterned on the inner surface of a cylinder act as lubrication and reduce friction. The active rotating tool presented here is equipped with a gap sensor that can measure the distance between the tool, workpiece, and machining tip so that micron-scale dimples and grooves can be patterned and connected to piezoelectric actuators. Electronic control and power connections are made to the external controller via a slip ring. Accurate measurements of the distance between the tool and workpiece were used to increase the lubrication effect by machining patterns with uniform size and depth. It is difficult to accurately measure errors in cylinders of various shapes using a single gap sensor; thus, we employed two gap sensors to ensure accurate assessment of cylinder shape, and a least mean square algorithm was implemented to compensate for the measured runout errors, which were tracked and compensated using the gap sensor. The method presented here reduces errors on the inner face of a cylinder, and produces a uniform pattern.

Developing efficient and stable electrocatalysts is crucial for the electrochemical production of pure and clean hydrogen. For practical applications, an economical and facile method of producing catalysts for the hydrogen evolution reaction (HER) is essential. Here, we report ruthenium (Ru) nanoparticles uniformly deposited on multi-walled carbon nanotubes (MWCNTs) as an efficient HER catalyst. The catalyst exhibits the small overpotentials of 13 and 17 mV at a current density of 10 mA cm–2 in 0.5 M aq. H2SO4 and 1.0 M aq. KOH, respectively, surpassing the commercial Pt/C (16 mV and 33 mV). Moreover, the catalyst has excellent stability in both media, showing almost “zeroloss” during cycling. In a real device, the catalyst produces 15.4% more hydrogen per power consumed, and shows a higher Faradaic efficiency (92.28%) than the benchmark Pt/C (85.97%). Density functional theory calculations suggest that Ru–C bonding is the most plausible active site for the HER., To efficiently produce pure and clean H2 through electrochemical processes, an efficient and durable catalyst is essential. Here, authors report ruthenium nanoparticles anchored on multi-walled carbon nanotubes as an efficient catalyst for H2 evolution in both acidic and alkaline media.

A functionally effective compatibilizer for PET/PPE blends is highly necessary to fabricate white opaque polyester film having high reflectance through drawing process. In this study, the effects of three different compatibilizers (SAN-g-MAH, SMA-16 and polystyrene-g-oxazoline PS-g-OXA) on the morphological, thermal, mechanical, and rheological properties in the PET/PPE (70/30, wt%) blend system were investigated. For the morphological studies, upon the addition of 7 part(s) per hundreds by weight (phr) of PS-g-OXA, the smallest domain size was observed among the three types used as a compatibilizer. Similarly, for the mechanical and rheological studies, upon the addition of 7 phr of PS-g-OXA, the optimal properties among three different compatibilizers were demonstrated due to the increased tensile strength and complex viscosity. For the thermal study, when the amount of PS-g-OXA added as a compatibilizer exceeded the threshold of the blend system, the Tg of the polyphenylene ether (PPE) was exhausted. In the morphological studies, the compatibilization effect was observed in the surface roughness of the film after stretching. It was concluded that PS-g-OXA was the effective compatibilizer for improving the reflectivity to make white opaque polyester film in PET/PPE blend system. It was concluded that this was due to compatibilization effects. Based on the results, the changes in properties were observed for biaxially oriented polyethylene terephthalate (PET)/PPE (70:30, wt%) blend films.

Prediction of microporosity (microshrinkage) formation in casting alloys continues to be a subject of high interest to metalcasters because failure to avoid this defect results in many instances in rejection of the casting with associated financial loss. It is a complex problem involving multiple material and process variables. Spheroidal graphite (SG) iron castings are particularly vulnerable to this type of defects because of the low mushy zone permeability associated with the late phases of solidification of this iron. A previously developed model that captures some important elements of the physics of the problem, including gas evolution in the melt with increasing fraction of solid and decreasing mushy zone permeability during solidification, was used to calculate the porosity distribution in L-shaped SG iron castings. The calculation results compared well with experimental observation on L-shaped castings. Some disagreements between calculations and experiments are attributed to gas pore migration during solidification, a phenomenon that is not included in the physics described by the model.

B2O3 and Li2O (B/L)-added Ba0.6Sr0.4TiO3 (BST) ceramics sintered at 940 °C exhibited a dense microstructure with large grains. The amount of B/L additive was 4.5 wt% with a B/L ratio of 1.5:1. The B/L-related liquid phase assisted the densification of the BST ceramics. This BST ceramic displayed a large dielectric constant (er) of 2834 with a low dielectric loss (tan δ) of 0.21% at 1.0 MHz. It also displayed a large tunability (28.2% at 10 kV/cm) and a high figure of merit (FOM) of 134. BST thick-films were synthesized using the tape casting method. The thick-film densified at 940 °C exhibited a large tunability of 18.7% at 10.0 kV/cm and an FOM of 208; these are higher than the values reported in the literature. Multilayer ceramics (MLCs) consisting of five layers of 40-μm-thick BST thick-films and Ag electrodes were also fabricated at 940 °C. No diffusion occurred between the Ag electrode and BST thick-film. A large tunability of 67.6% at 52 kV/cm with a high FOM of 294 was obtained from this MLC. This verified that the B/L-added BST ceramic is effective for application in tunable multilayer devices.

This study investigates the impact of the fuel cetane number on the ignition and combustion dynamics of a high-pressure jet fuel spray under realistic diesel engine conditions. Under the desirable ...

This study analyzed variations of tensile strength and the failure mode of composite bonded scarf joint in various thermal environments. A total of 70 scarf bonded joints were manufactured using se...

LED operating under high-temperature condition badly affects reliability. To reduce junction temperature of LED is crucial. In this paper, luminous intensity and photo conversion efficient with respect to electrical power are discussed. Moreover, three arrangements for LED module are suggested, and design parameters are discussed in terms of the number of LEDs and distance between each LED. In order to evaluate thermal performance of designed the module, computer simulation was conducted. Distance between each LED is selected by 7.6, 9.6, and 13.3mm for 80, 128, and 240 LEDs, respectively and unit heat flux is calculated to be 0.47W/mm2 , 0.29W/mm2 , 0.16W/mm2 for 80, 128, and 240 LEDs, respectively. In this case, Maximum temperature on the PCB was 67.8C, 62.5C, and 57.1C for 80, 128, and 240 LEDs, respectively. The Maximum temperature and unit heat flux was reduced by 15.7% and 66%, respectively, when the number of LEDs are increased by three times. We found that the temperature between LEDs can be reduced if unit heat flux can be reduced.

The unitized regenerative fuel cell (URFC) is a useful electrochemical energy conversion/storage device, in which catalysts for the dual-function (oxygen reduction reaction, ORR, and oxygen evoluti...

The nonlinear rheological response to extensional flows in entangled polymers is related to the segmental chain stretching and to the chemical identity of the monomeric units. The latter has a strong effect on the drag coefficients, and therefore, quantification of molecular conformation changes in the subnanometer scale (at the monomer level) are crucial to fully understand nonlinear viscoelastic behavior in polymer melts. We report in situ time-resolved extensional rheo-small-angle neutron scattering (tEr-SANS) and wide-angle X-ray scattering (tEr-WAXS) during startup of uniaxial flow on a monodisperse polystyrene melt. Flow-induced segmental alignment was quantified with tEr-SANS, whereas local alignment of the backbone-backbone and phenyl-phenyl interactions were measured with tEr-WAXS. Linear relations between the three alignment factors and stress were observed at low stresses, which confirmed the validity of simple stress-SANS and stress-WAXS rules (SSR and SWR, respectively). Significant differences in SSR and SWR coefficients, as well as the stress values for failure of the two rules suggest very different correlations between global (at the segmental level) and local (at the monomer level) conformations with stress.

A new lead-free piezoelectric film consisting of Sr2NaNb4O13− (SNNO−) and TiNbO5− (TNO−) nanosheets was fabricated via electrophoresis. SNNO and TNO films display paraelectric polarization versus electric field (P-E) loops. However, a new film composed of a mix of SNNO− and TNO− (S/T) nanosheets displayed a ferroelectric P-E hysteresis loop with large maximum polarization (18.7 μC/cm2), remnant polarization (7.7 μC/cm2), and a coercive electric field (86 kV/cm). The interfaces formed between the SNNO and TNO layers induced ferroelectric properties in the S/T film through the occurrence of polar distortion and octahedral tilting in the film. Ferroelectric properties were also observed in piezoelectric force microscopy images of the S/T film, which showed 90° domains after the removal of the applied electric field. The dielectric constant of the S/T film was 70, which is higher than those of SNNO and TNO films, indicating that the S/T film is a ferroelectric material. The piezoelectric strain constant of the S/T film was 156 p.m./V and promising insulating properties were observed therein. The growth temperature of the S/T film was low (300 °C), suggesting that the S/T film can be used for flexible electronic devices.