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Acetaminophen (paracetamol, APAP) is a major component of Tylenol, Penzal Q, and Panpyrin, and is the most commonly used antipyretic analgesic in children. The conventional oral drug delivery systems of APAP are pills and tablets. However alternative drug delivery methods are desirable in case of pediatric or geriatric patients, especially for drugs like APAP that must be taken in large doses at once. Another requirement for a good drug delivery system is the rapid dissolution to ensure a rapid therapeutic action as pain reliever. In this study Acetaminophen (paracetamol, APAP) was encapsulated in a water-soluble polymer. After the preparation of the solid dispersion by encapsulating acetaminophen in polyvinylpyrrolidone, the resultant granules were used in three formulations: tablets, chewable tablets, and oral dissolving films (ODF). Solid dispersions and prepared formulations were evaluated by Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffractometer (XRD), and universal tensile machine (UTM), and the release behavior was compared. As a result, it was confirmed that the oral dissolving films can be taken easily because it has the advantages of both tablet and liquid dosage form accurate dosage, easy administration, easy swallowing, and fast bioavailability. Furthermore, the drug absorption rate can be effectively increased by changing the formulation.

The purpose of this study was to improve the processability of rice powder using fluidised-bed granulation technology. Bukkyungmi-rice granules were prepared by fluidised-bed granulation for 1 and 2 h using water, 5% lactose (w/v) and 5% dextrin (w/v) solutions as dispersants. The particle size of Bukkyungmi-rice granules increased from 574.83 to 728.07 μm. Granules were produced due to pore formation, and the produced particles could be dispersed easily without any entanglement. The water solubility of the produced rice granules is 1.91–6.74%, which reflects the improvement in their quality with increased treatment time. In particular, Bukkyungmi-rice granules processed in 5% dextrin showed excellent settleability. The enthalpy (ΔH) was found to be the highest for Bukkyungmi-rice granules processed in 5% dextrin for 2 h by differential scanning calorimetry. The results indicated that rice granules obtained by fluidised-bed granulation could be used in various types of rice-based foods.

This paper describes utilization of dielectric barrier discharge (DBD) plasma interaction with impregnated surface nano-particles for plasma applications. The plasma generation characteristics on DBD plasma actuator and packed-bed reactor are investigated with unexpected objects as impregnated catalysts. The streamer generation of DBD plasma is influenced by different surface nano-particles of the impregnated catalyst between the discharge gaps. The practical use of DBD plasma-catalyst interaction is discussed.

In this study, a sustainable air plasma-based nitrogen fixation into reactive nitrogen species in water (e.g. nitrate and nitrite) is presented, which mimics the lightning-based nitrogen fixation that occurs in nature. We report a hybrid plasma system that combines a dielectric barrier discharge (DBD) reactor (as an efficient ozone source) and an arc plasma reactor (as an efficient NOx source). This hybrid plasma system completely converts gaseous NOx and O-3 into NOx- in water with almost zero emissions (NOx and O-3). Gaseous outlets, in-liquid species, and electrical parameters were investigated. The energy cost for nitrate production via a single-pass reaction was extremely reduced to 8 MJ mol(-1), which enhanced the applicability of the direct one-step nitrogen fixation into NOx- in water for distributed fertilizer production to decrease the dependence on the Haber-Bosh process toward sustainable agricultural development.

Hydrogen energy is one of the key technologies that can help to prevent global warming. A water electrolysis process can be used to produce hydrogen, in which hydrogen is produced at one electrode of the electrochemical cell, and oxygen is produced at the other electrode. On the other hand, the oxygen evolution reaction (OER) requires multiple reaction steps and precious-metal-based catalysts (e.g., Ru/C, Ir/C, RuO2, and IrO2) as electrocatalysts to improve the reaction rate. Their high cost and limited supply, however, limit their applications to the mass production of hydrogen. In this study, boron, nitrogen-doped carbon incorporated with molybdenum carbide (MoC-BN/C) was synthesized to replace the precious-metal-based catalysts in the OER. B, N-doped carbon with nanosized molybdenum nanoparticles was fabricated by plasma engineering. The synthesized catalysts were heat-treated at 600, 700, and 800 &deg, C in nitrogen for one hour to enhance the conductivity. The best MoC-BN/C electrocatalysts (heated at 800 &deg, C) exhibited superior OER catalytic activity: 1.498 V (vs. RHE) and 1.550 V at a current density of 10 and 100 mA/cm2, respectively. The hybrid electrocatalysts even outperformed the noble electrocatalyst (5 wt.% Ru/C) with higher stability. Therefore, the hybrid electrocatalyst can replace expensive precious-metal-based catalysts for the upcoming hydrogen economy.

This report proposes a method that uses plasma in combination with combustion to remove very low concentrations of volatile organic compounds (VOCs) that cannot be combusted with conventional burners. A burner with a fuel-rich pilot flame with an equivalence ratio of 1.5, 2, or 2.5 was formed, and a rotating arc plasma with a specific energy input (SEI) of 0–1.2 kJ/L was applied. When the plasma was used in the pilot flame, the temperature of the emitted gas increased, as did the concentration of combustible gas in the emitted gas, such that the selectivity reached a maximum of 0.8 (CO), 0.4 (H2), and 0.06 (C2H2). Lean VOC emission was simulated by preparing a mixture of propane and nitrogen with nitrogen content of 98% or 99% and this mixture was sprayed downstream from the plasma pilot flame to form the main flame. The combustion state of the main flame and exhaust gas was then analyzed to measure the hydrocarbon treatment ratio. The results showed that, when high-SEI plasma was employed in a high-equivalence-ratio pilot flame, NOx emission remained minimal and an HC treatment ratio close to 1 was obtainable. The use of this method for combustion enables the flow rates of treatable VOC mixtures to be specified such that the concentration of CO and NOx in the emitted gases is minimized.

This paper describes the performance degradation of impregnated catalyst in the dielectric barrier discharge (DBD) plasma-assisted methane conversion process. Mn and Ni mixed copper-zinc catalysts, and bare γ-Al2O3 support were exposed to the DBD plasma generated at 1 kHz and 9 kV under CH4 direct conversion for 4 hours. The performance degradation due to the surface damage of the catalyst by the plasma was investigated by SEM analysis.

Transition-metal-based catalysts are considered to be promising oxygen evolution reaction (OER) catalysts with lost capital cost and high durability. Herein, a core-double shell nanocubic γ-Fe2O3@FeS2@C with energy level matching was fabricated to regulate the electrochemical electronic structure and enable efficient charge transfer at the double-interface, which could effectively reduce the OER reaction barrier and activate fast OER kinetics. Although the concept of energy level matching has been widely applied in semiconductor, it was rarely studied in OER electrocatalyst. The γ-Fe2O3@FeS2@C catalyst displayed exceptional small overpotential (268 mV) at 10 mA/cm2 and Tafel slope (54 mV/dec), which was superior than that of the benchmark 20 wt% Ir/C catalyst (with an overpotential of 287 mV and a Tafel slope of 71 mV/dec). This work presented a novel approach for developing earth‐abundant and highly active OER electrocatalysts based on energy level matching and phase transformations for alkaline-based water electrolysis.

A novel concurrent process for CO2 reduction and plastic upcycling was successfully developed based on a rotating gliding arc plasma process, where CO2 gas and Low-density polyethylene (LDPE) powder were used as reactants for the process. Herein, the LDPE powder was regarded as an alternative of plastic waste, and the high temperature of the plasma jet thermochemically decomposed the plastic powder. Based on gas chromatography analyses, the yields of the C1 and C2 chemicals were confirmed, which demonstrated the possibility for the chemical upcycling of the plastic powder with CO2 plasma jet. At the same time, the conversion of CO2 at the exhaust gas increased with increasing electric power of the plasma jet. In addition, as the electric power further enhanced, the reverse reactions were efficiently suppressed by the chemical quenching process due to complete depletion of the oxygen by the light hydrocarbon gases generated from the pyrolysis of the plastic powder. Based on the molecular balance of C and O, the calculated syngas to CO2 ratio was achieved up to 32 % in a batch-type plasma reactor with a power supply of 1170 W. It is rational inference that the efficiency will be significantly improved if a plug-in type plasma reactor with higher power supply is implemented. In conclusion, this novel concurrent process would be a promising approach for an efficient and scalable technology of CO2 utilization.

Tissue engineered bone substitutes should mimic natural bone characteristics to be highly-suitable for treating bone defects in addition to its biocompatibility and good mechanical stability. In this study, we performed a detailed in vivo bone regeneration evaluation of 80 wt% duck’s feet collagen/poly(lactide-co-glycolide) scaffolds (DC/PLGA) fabricated by solvent casting/salt leaching strategy in a rat calvarial defect as model. We have already shown a strong influence of DC/ PLGA scaffolds on bone regeneration in terms of biomaterial cohesion, architecture, mechanical features, and in vitro biological properties. The as-fabricated scaffold has shown significant increase in osteogenesis, initial bone formation and differentiation, ascribed to the high percentage of DC in the 80 wt% DC/PLGA scaffold. The in vivo implanted scaffold was found be well-attached to the bone defect region and eventually gets integrated with the surrounding tissues without any pronounced inflammatory reactions. Compared to bare PLGA, an increased recovery in bone volume was observed at 8th week post-surgery. Thus, the 80 wt% DC/PLGA scaffold can be envisioned as a potential alternative bone graft in bone tissue engineering.

Tough mechanical properties are generally required for tissue substitutes used in regeneration of damaged tissue, as these substitutes must be able to withstand the external physical force caused by stretching. Gelatin, a biopolymer derived from collagen, is a biocompatible and cell adhesive material, and is thus widely utilized as a component of biomaterials. However, the application of gelatin hydrogels as a tissue substitute is limited owing to their insufficient mechanical properties. Chemical cross-linking is a promising method to improve the mechanical properties of hydrogels. We examined the potential of the chemical cross-linking of gelatin hydrogels with carboxy-group-modified polyrotaxanes (PRXs), a supramolecular polymer comprising a poly(ethylene glycol) chain threaded into the cavity of &alpha, cyclodextrins (&alpha, CDs), to improve mechanical properties such as stretchability and toughness. Cross-linking gelatin hydrogels with threading &alpha, CDs in PRXs could allow for freely mobile cross-linking points to potentially improve the mechanical properties. Indeed, the stretchability and toughness of gelatin hydrogels cross-linked with PRXs were slightly higher than those of the hydrogels with the conventional chemical cross-linkers 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS). In addition, the hysteresis loss of gelatin hydrogels cross-linked with PRXs after repeated stretching and relaxation cycles in a hydrated state was remarkably improved in comparison with that of conventional cross-linked hydrogels. It is considered that the freely mobile cross-linking points of gelatin hydrogels cross-linked with PRXs attenuates the stress concentration. Accordingly, gelatin hydrogels cross-linked with PRXs would provide excellent mechanical properties as biocompatible tissue substitutes exposed to a continuous external physical force.

Porous zinc oxide (ZnO) spheres were synthesized by facile low temperature solution route. The as-synthesized porous ZnO spheres were characterized in detail in terms of their morphological, structural, optical and photocatalytic properties using field-emission scanning electron microscopy (FESEM, equipped with energy dispersive spectroscopy (EDS)), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), X-ray diffractometer (XRD), UV–visible spectroscopy and Raman-scattering measurements. Nitrogen adsorption-desorption analysis was performed to determine pore size distribution from the adsorption isotherm curves using the Barrett-Joyner-Halenda (BJH) method. Morphological and structural characterizations showed porous nature of ZnO spheres with high surface area, good crystallinity, wurtzite hexagonal phase and good optical features. Next, ZnO spheres were studied as photocatalyst for photodegradation of harmful dye, methyl orange (MO). Under ultraviolet light irradiation, the decrease in MO dye concentration was monitored by UV–visible spectroscopy at different time intervals until the dye was completely degraded to colorless end product. Rapid MO dye decomposition was observed with a degradation rate of ~ 96.3% within the initial 120 min, which is attributed to the porous nature, large specific surface area (114.6 m2 g− 1), narrow pore size distribution (~ 2.5 to 25 nm) evaluated from N2 adsorption-desorption isotherms analysis and excellent electron accepting features of the engineered porous ZnO spheres.

In this study, we have designed scaffold by mixing collagen extracted from the duck’s flippers with poly(vinyl alcohol) (DC/PVA) via freeze-thawing and the as-prepared scaffold were evaluated for skin regeneration. The physical and chemical properties of the scaffolds were characterized using FTIR, SEM, compressive strength, degree of swelling, etc. The in vitro behavior (cell proliferation) was examined after cultured with fibroblasts through the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay. The in vivo results demonstrated that the scaffolds implanted in rat induced full-thickness defect, confirmed by histological staining. Encompassing all results, the DC/PVA scaffolds can be anticipated as efficient platforms for skin regeneration facilitating required cell adhesion, growth and proliferation.

The JSNS$^{2}$ (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source) experiment will search for neutrino oscillations over a 24 m short baseline at J-PARC. The JSNS$^{2}$ inner detector will be filled with 17 tons of gadolinium-loaded liquid scintillator (LS) with an additional 31 tons of unloaded LS in the intermediate $\gamma$-catcher and outer veto volumes. JSNS$^{2}$ has chosen Linear Alkyl Benzene (LAB) as an organic solvent because of its chemical properties. The unloaded LS was produced at a refurbished facility, originally used for scintillator production by the RENO experiment. JSNS$^{2}$ plans to use ISO tanks for the storage and transportation of the LS. In this paper, we describe the LS production, and present measurements of its optical properties and long term stability. Our measurements show that storing the LS in ISO tanks does not result in degradation of its optical properties., Comment: 7 pages, 4 figures

There is a significant rise in the bone grafts demand worldwide to treat bone defects owing to continuous increase in conditions such as injury, trauma, diseases, or infections. Therefore, development of three-dimensional scaffolds has evolved as a reliable technology to address the current limitations for bone tissue regeneration. Mimicking the natural bone, in this study, we have designed a silk fibroin/hydroxyapatite scaffold inlaid with a bioactive phytochemical (quercetin) at different concentrations for promoting osteogenesis, especially focusing on quercetin ability for enhancing bone health. Characterization of the quercetin/silk fibroin/hydroxyapatite (Qtn/SF/HAp) scaffolds showed an increased pore size and irregular porous microstructure with good mechanical strength. The Qtn (low-content)/SF/HAp scaffold was found to be an efficient cell carrier facilitating cellular growth, osteogenic differentiation, and proliferation as compared to SF/HAp and Qtn (high-content)/SF/HAp scaffolds. However, Qtn (high-content)/SF/HAp was observed to inhibit cell proliferation without any effects on cell viability. In vitro and in vivo outcomes studied using bone marrow-derived mesenchymal stem cells (rBMSCs) confirm the cytocompatibility, osteogenic differentiation ability, and prominent upregulation of the bone-specific gene expressions for the rBMSCs-seeded Qtn/SF/HAp scaffolds. In particular, the implanted Qtn (low-content)/SF/HAp scaffolds at the bone defect site were found to be well-attached and amalgamated with the surrounding tissues with approximately 80% bone volume recovery at 6 weeks after surgery as compared with other groups. Based on the aforementioned observations highlighting the quercetin efficiency for bone regeneration, the as-synthesized Qtn (low-content)/SF/HAp scaffolds can be envisioned to provide a biomimetic bone-like microenvironment promoting rBMSCs differentiation into osteoblast, thus suggesting a potential alternative graft for high-performance regeneration of bone tissues.

This paper describes modification of catalyst surface from interaction between catalysts and dielectric barrier discharge (DBD) plasma. Ru/γ–Al₂O₃ catalyst was exposed to DBD plasma for CO₂ methanation and CH₄ direct conversion reactions. Parameters related to the modification of catalyst surface were investigated by SEM and EDS analysis.

This study was conducted to examine the physicochemical properties and micro-encapsulation process of rice fermented with Bacillus subtilis CBD2. The viable bacterial cell, pH, and amylase activity of the rice liquid culture were 7.61 log CFU/mL, pH 5.08 and 159.43 units/mL, respectively. The micro-encapsulated rice liquid culture was manufactured via spray drying with different forming agents: i.e., alginic acid 1.0% and chitosan 0.3%, 0.5%, and 1.0%. The moisture contents of the spray-dried powders were approximately 2.90~3.68%. The color of the L and a value decreased whereas that of the b and ΔE value increased. The particle size and outer topology of the spray-dried rice liquid culture were 48.13~68.48 μm and globular, respectively. The water absorption index of the spray-dried powder (2.40~2.65) was lower than that of the freeze-dried powder (2.66). The water solubility index of the spray-dried powder (9.17~10.89%) was higher than that of the freeze-dried powder (7.12%). The in vitro dissolution was measured for five hours in pH 1.2 simulated gastric fluid, and pH 6.8 and pH 7.4 simulated intestinal fluids, using a dissolution tester at 37°C with 50 rpm agitation. The amylase survival in the fermented rice was 85.93% through the spray-drying and it was very effectively controlled.

One of the environmental issues in semiconductor and flat panel manufacturing industries is to reduce emission of perfluorocarbons(PFCs) used in etching process and cleaning CVD chambers [1]. At present, several types of PFCs abatement device are already installed in the industries, which are incinerator, catalytic combustor, and plasma treatment systems. Removal of CF 4 has been tried via catalytic reaction of CF 4 decomposition. This study exploits a possible way of plasma-catalyst combination for the removal of CF 4 . Rotating arc reactor that can produceone of thermal plasma [2] and following catalyst bed has been applied. In this configuration, arc plasma itself destroys CF 4 and also provides heat required for the catalytic reaction. From experiments, the removal rate of CF 4 was estimated by plasma only and plasma-catalyst combination system. The quantity of water vapor which can prevent reverse reaction of decomposed CF 4 was also considered to present optimal quantity of water in CF4 removal reaction.From this work, the feasibility of the combination of plasma and catalyst is confirmed and further studies are needed to realize this hybrid system in an optimal way for real applications.

Accelerated global warming resulted in diverse regulations for possible removal of greenhouse gases. N2O is one of global warming gases that is produced in the course of combustion process and incomplete reduction of NOx. Removal of N2O has been tried via catalytic reaction of N2O decomposition1. This study exploits possible way of plasma-catalytic removal of N2O. MnO2/Al2O3 and Ru/Al2O3 are considered as a catalyst for plasma-catalysis2. Thermal plasma and following catalyst bed has been applied. In this configuration, arc plasma itself destroys N2O and also provides heat required for the catalytic reaction. In the experiment that adopted Ru/Al2O3 as catalyst showed good removal efficiency. As byproducts, small amount of NO2 that can be removed by a scrubber is measured, but NO is not detected. From this work, the feasibility of the combination of plasma and catalyst is confirmed and further studies are needed to realize this hybrid system in an optimal way for real applications.

Transdermal drug delivery system (TDDS) was prepared with temperature-responsive hydrogel. The graphite was oxidized and incorporated into hydrogel matrix to improve the thermal response of hydrogel. The micro heater was fabricated to control the temperature precisely by adopting a joule heating method. The drug in hydrogel was delivered through a hairless mouse skin by controlling temperature. The efficiency of drug delivery was improved obviously by incorporation of graphite oxide due to the excellent thermal conductivity and the increased interfacial affinity between graphite oxide and hydrogel matrix. The fabricated micro heater was effective in controlling the temperature over lower critical solution temperature of hydrogel precisely with a small voltage less than 1 V. The cell viability test on graphite oxide composite hydrogel showed enough safety for using as a transdermal drug delivery patch. The performance of TDDS could be improved noticeably based on temperature-responsive hydrogel, thermally conductive graphite oxide, and efficient micro heater.

A plasma-assisted staged combustor that can reduce NOx generation is introduced. This combustor is based on a commercial combustor. Only the internal structure of the commercial combustor head was ...

The Because of its high thermal efficiency, the direct injection (DI) diesel engine has emerged as a promising potential candidate in the field of transportation. However, the amount of nitrogen oxides (NOx) increases in the local high-temperature regions and that of particulate matter (PM) increases in the diffusion flame region during diesel combustion. In the de-NOx system the Lean NOx Trap (LNT) catalyst is used, which absorbs NOx under lean exhaust gas conditions and releases it in rich conditions. This technology can provide a high NOx-conversion efficiency, but the right amount of reducing agent should be supplied to the catalytic converter at the right time. In this research, the emission characteristics of a diesel engine equipped with a micro-reformer that acts as a reductants-supplying equipment were investigated using an LNT system, and the effects of the exhaust-gas temperature were also studied.

The stretch breaking process has been useful in the cotton industry because long staple fibers such as wool need to be shortened so that they can be spun in the cotton spinning system with its higher production rate. The blending of wool with other fibers such as wool/cotton, wool/ micro-fiber and several wool-blended yarns produces diverse wool products. In the present study, the distribution functions of the fiber length after the stretch breaking process have been newly derived after considering the fiber's recovery function. The number and mean length of the fibers after the stretch breaking process have been investigated by the computer simulation according to variables such as the roller gauge, the breaking strain of the fiber, and the standard deviation of the fiber length.

Iron carbide Fe 3 C nanoparticles were fabricated by a chemical vapor condensation (CVC), and their structural and magnetic properties were investigated. It was found that the formation of iron carbide nanoparticles strongly depended on reaction temperature and pressure. The iron carbide was formed only above 650 °C at 101 kPa (760 Torr) but never formed in vacuum (1.33 Pa) regardless of reaction temperature. The fabricated iron carbide nanoparticles were spherical with T c of about 240 °C. While the particles formed at 650 °C (∼30 nm) possessed a typical core–shell structure, those formed at 800 °C (∼50 nm) did not have such structure. The nanoparticles fabricated at 650 °C and 800 °C at 101 kPa, exhibited M s of ∼125 A m 2 /kg whereas i H c of the former was slightly higher (∼63 kA/m) than that of the latter (∼40 kA/m).

A preplated frame (PPF) consisting of Au/Pd/Cu-Sn/Cu substrate, i.e., preplated with a Cu-Sn alloy instead of Ni commercially used, was fabricated by electroplating and then the feasibility of the frame as an alternative PPF was investigated. The wettability of the Cu-Sn alloy was better than that of Ni, resulting in excellent contact with the substrate and smoother surface on the upper Au/Pd protective layer. By XPS analyses, it was confirmed that Cu atoms in the Cu-Sn alloy layer did not diffuse through the thin protective layer to the surface at temperatures used in IC assembly. The wire pull-strength and solderability of the Cu-Sn alloy PPF were almost equivalent to those of the Ni PPF. However, the former showed much better corrosion resistance than the latter.

Short wool fibers obtained by the stretch breaking process can be blended with cotton fibers and processed in a cotton spinning system, which has a high production rate. For the structural property of the wool fiber after stretch breaking, the diameter and length of the wool fiber were measured as a function of time. The diameter of the broken fibers was finer than the diameter of untreated fibers. The fiber diameter at the break point was the finest and was more irregular than the original fiber. The broken fiber showed mechanical properties of increased modulus, decreased breaking strain, and increased breaking strength.

Effects of surface defect distribution on flame instability during flame-surface interaction are experimentally investigated. To examine chemical quenching phenomenon which is caused by radical adsorption and recombination processes on the surface, thermally grown silicon oxide plates with well-defined defect density were prepared. ion implantation technique was used to control the number of defects, i.e. oxygen vacancies. In an attempt to preferentially remove oxygen atoms from silicon dioxide surface, argon ions with low energy level from 3keV to 5keV were irradiated at the incident angle of . Compositional and structural modification of induced by low-energy ion irradiation has been characterized by Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). It has been found that as the ion energy is increased, the number of structural defect is also increased and non-stoichiometric condition of is enhanced.

In order to realize a stably propagating flame in a narrow channel, flame instabilities resulting from flame-wall interaction should be avoided. In particular flame quenching is a significant issue in micro combustion devices; quenching is caused either by excessive heat loss or by active radical adsorptions at the wall. In this paper, the relative significance of thermal and chemical effects on flame quenching is examined by means of quenching distance measurement. Emphasis is placed on the effects of surface defect density on flame quenching. To investigate chemical quenching phenomenon, thermally grown silicon oxide plates with well-defined defect distribution were prepared. ion implantation technique was used to control defect density, i.e. the number of oxygen vacancies. It has been found that when the surface temperature is under , the quenching distance is decreased on account of reduced heat loss; as the surface temperature is increased over , however, quenching distance is increased despite reduced heat loss effect. Such abberant behavior is caused by heterogeneous surface reactions between active radicals and surface defects. The higher defect density, the larger quenching distance. This result means that chemical quenching is governed by radical adsorption that can be parameterized by oxygen vacancy density on the surface.

Nanocrystalline Nd-Fe-B powder was synthesized by a new thermochemical process that combined with past reduction-diffusion process and spray-dry process. In this process, Ca reduction process is vary important due to formation of hard magnetic phase from various oxides by Ca powder. Therefore, the final products are essentially affected a shape, size, and composition etc. of the Ca reduced powders. Ca reduction was performed to way that raw powders just mixed with Ca powder in proper ratio unlike to compress into compact. The powders after mixture-type Ca reduction mainly composited with phase even relativily low reaction temperature () and all particle size of powder were distributed less than 1 except for powder after Ca oxides as magnetic properties of powders after cake-type Ca reduction, with the consequence that high magnetic properties has been expected. The magnetic properties of powders prepared by mixture-type Ca ruduction, with the conseqence that high magnatic properties has been expected. The magnetic properties of powders prepared by mixture-type Ca reduction process showed

Combustion Characteristics and quenching criteria of micro combustor in various condition was exploited experimentally. Two different gases were used, and various geometric matrixes were considered to figure out quenching characteristic of micro combustor. The micro combustor studied in this study was constant volume, and has cylindrical shape. Geometric parameter of combustor was defined to be combustor height and diameter. The effect of height was exploited parametrically as 1 mm, 2mm and 3mm and the effect of diameter was parameterized to be 7.5mm and 15mm. Three different combustibles. (1) Stoichiometric mixture of methane and are, (2) Stoichiometric mixture of hydrogen and air and (3) Mixture of hydrogen and air with fuel stoichiometry of two were used. Pressure transition during combustion process was recovered. The ratio of maximum pressure to initial pressure responded favorably with the change of height of combustor and the initial pressure, the maximum pressure was also increased. The flame propagation was observed only when a specific condition was satisfied. From the experiment the condition that guarantees stable propagation of flame was tabulated. The tabulated results includes criteria of quenching according to combustor height, combustor diameter, species of fuel and initial pressure.

In this paper research on micro solid propellant thruster is reported. Micro solid propellant thruster has four basic components; micro combustion chamber, micro nozzle, solid propellant and micro igniter. In this research igniter, solid propellant and combustion chamber are focused. Micro igniter was fabricated through typical micromachining and the effect of geometry was evaluated. The characteristic of solid propellant was investigated to observe burning characteristic and to obtain burning velocity. Change of thrust force and the amount of energy loss following scale down at micro combustion chamber were estimated by numerical simulation based on empirical data and through the calculation normalized specific impulses were compared to figure out the efficiency of combustion chamber.

Experiment study on a down scaled two-phase catalytic reactor is presented. As a preliminary step for the development of catalytic reactor, nano-particulate catalyst was prepared. Perovskite La0.8/Sr0.2/CoOis chosen and synthesized as a catalyst considering superior catalytic performance in reduction and oxidation process where oxygen is involved among the reagent. Reactor that has a scale of 21025mm was made by machining of A1 block as a layered structure considering further extension to micro-machining. Hydrogen peroxide of 70wt% was adopted as reactant and was provided to the reactor loaded with 1.5 g of catalyst. Reactant flow rate was varied by precision pump with a range of 0.15cc/min to 17.2cc/min. Temperature distribution within reactor was recorded by 3 thermocouples and total amount of liquid product was measured. Temperature distribution and factors that affect temperature were observed and relation between temperature distribution and production rate was also analyzed. Relative time scale plays a significant role in the performance of the reactor. To obtain steady state operation, appropriate ratio of flow rate, catalyst mass and reactor geometry is required and furthermore to get more efficient production rate temperature distribution should be evenly distributed. The database obtained by the experiment will be used as a design parameter for micro reactor.

Analysis model for the two-phase catalytic reactor is presented. With the progress in development of micro thermofluidic devices, needs fur understanding of the phenomena in two phase reaction in cm scale has been arisen. To investigate thermal and reactive performance of down scaled two phase reactor simple analysis model that is a kind of lumped flow model is proposed. Analysis model presented is based on the experiment on mm scale model reactor. Target experiment is catalytic decomposition of 70wt％ hydrogen peroxide with existence of perovskite L S Co catalyst. It is composed of balance equations of mass and energy. Each phase is considered to be a species fur the simplicity. Axial diffusion and transversal distribution of properties are neglected. Two phase catalytic reaction is modeled as successive gasification of liquid lump around catalyst and reaction in gas phase. Heat transfer is modeled by model function ofNu number. Modeled Nu is expressed as Nu

In the present study, a numerical simulation of flame propagation and extinction in a micro combustor that is subject to excessive heat loss to the wall, particularly during flame propagation, is described. Heat loss to the wall was empirically modeled from measurement data on a similarly configured micro combustor. A PISO based numerical scheme was used for differencing the conservation equations. An H2-air reaction mechanism involving 16 species and 10 reaction steps was used to approximate the combustion process. A cylindrical computation domain was used to simulate the experiments. The combustor volume has a small height to radius ratio and an axial gradient of properties can be significant. In the present study, however, axial gradients were ignored, leaving radius as the only spatial coordinate. Instead of evaluating heat transfer from the temperature gradient near the wall surface, an empirical bulk heat transfer coefficient was used to approximate heat loss to the wall. A comparison of the computa...

In this study, expanded starch/poly(vinyl alcohol) (PVA) blends for packing material were prepared by using calcium carbonate as the expansion inhibitor to investigate the degradability and the structural and mechanical properties of expanded starch/PVA/calcium carbonate blends (ESPCs). The structure of ESPCs became more compact with increasing CaCO3 content and at least 2 parts of CaCO3 were required to obtain the sufficient inhibiting effect on the expansion. As CaCO3 content increased from 1 to 4 parts, tensile strength more than doubled from 70 to 180 KPa, while elongation at break increased about 1.5-fold. The moduli of ESPCs also increased with increasing CaCO3 content, but they decreased continuously with exposure to UV radiation over all periods of exposure and remained in the range of 10–15 KPa after exposure for 7 weeks. The weight loss of ESPCs due to exposure to soil environment increased with exposure time and the final weight loss after the 5-week exposure was about 25–30%. Specifically, the degradability of ESPC with 20 parts of PVA was 5% higher than that of ESPC with 30 parts of PVA. The water solubility of ESPC with 30 parts of PVA was somewhat higher than that of ESPC with 20 parts of PVA. Furthermore, most of ESPCs began to be degraded thermally at 292°C. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 911–919, 2004

A numerical simulation of flame propagation in a micro combustor was carried out. Combustor has a sub -millimeter depth cylindrical internal volume and axisymmetric one-dimensional was used to simplify the geometry. Semi-empirical heat transfer model was used to account for the heat loss to the walls during the flame propagation. A detailed chemical kinetics model of with 10 species and 16 reaction steps was used to calculate the combustion. An operator-splitting PISO scheme that is non-iterative, time-dependent, and implicit was used to solve the system of transport equations. The computation was validated for adiabatic flame propagation and showed good agreement with existing results of adiabatic flame propagation. A full simulation including the heat loss model was carried out and results were compared with measurements made at corresponding test conditions. The heat loss that adds its significance at smaller value of combust or height obviously affected the flame propagation speed as final temperature of the burnt gas inside the combustor. Also, the distribution of gas properties such as temperature and species concentration showed wide variation inside the combustor, which affected the evaluation of total work available of the gases.

Combustion measurement in a cylindrical micro combustor, the construction procedureand test run of a MEMS reciprocating device are described. The sizing of the MEMSdevice was based on the findings of combustion measurements. Thermodynamic analysisof the pressure measurement resulted in available work up to 2.4 Joules in a combustorheight of 2 mm and more with combustion efficiency of 0.6;0.7. With combustor heightless than 2 mm, combustion was incomplete due to excessive heat loss to the wall. In orderto achieve the chamber height imposed by the combustion measurement, a fabricationprocess and wafer material that allow deeper etching was used.@DOI: 10.1115/1.1565095#Keywords: Combustion, Combustors, Heat Transfer, Internal, Microscale, Reacting

Investigation of the combustion phenomena in a constant volume microcombustor was carried out on a constant volume microcombustor that is subject to significant heat loss to the wall in order to estimate the effects of combustor dimension on flame propagation. A cylindrical combustor of a variable height that is comparable to quenching limit of the combustible mixture of H2 and air was built. Flame visualization and measurement of transient pressure during the flame propagation were made. Measurements were made at the chamber height ranging from 0.67 mm to 3 mm. A simple theoretical model that takes into account the heat loss to the wall during flame propagation was used to derive available work of the burnt gas from the pressure measurements. For a chamber depth of less than 1 mm, the pressure increase by combustion was negligible and the sensible heat in the burnt gas was not adequate to be converted to mechanical power. For a chamber height greater than 2 mm, however, the amount of heat generated by co...

Micro engine that includes Micro scale combustor is fabricated. Design target was focused on the observation of combustion driven actuation in MEMS scale. Combustor design parameters are somewhat less than the size recommended by feasibility test. The engine structure is fabricated by isotropic etching of the photosensitive glass wafers. Electrode formed by electroplating of the Nickel. Photosensitive glass can be etched isotropically with almost vertical angle. Bonding and assembly of structured photosensitive glass wafer form the engine. Combustor size was determined to be 1 mm scale. Movable piston is engraved inside the wafer. Ignition was done by nickel spark plug which was electroplated with thickness of 40 . The wafers were bonded by epoxy that resists high temperature. In firing test due to the bonding method and design tolerance pressure buildup by reaction was not confirmed. But ignition, flame propagation and actuation of micro structure from the reaction was observed. From the result basement of design and fabrication technology was obtained.

Micro engine that includes Micro scale combustor is fabricated. Design target was focused on the observation of combustion driven actuation in MEMS scale. Combustor design parameters are somewhat less than the size recommended by feasibility test. The engine structure is fabricated by isotropic etching of the photosensitive glass wafers. Electrode is formed by electroplating of the Nickel. Photosensitive glass can be etched isotropically with almost vertical angle. Bonding and assembly of structured photosensitive glass wafer from the engine. Combustor size was determined to be 1mn scale. Piston in cylinder moves by fuel injection and reaction. In firing test, adequate engine operation including ignition, flame propagation and piston motion was observed. Present study warrants further application research on MEMS scale internal combustion power units.

Down scaled combustor undergoes increased heat loss that results in incomplete combustion or quenching of the flame as a consequence. Therefore, effect of enhanced heat loss should be understood to design a MEMS scale combustion devices. Existing combustion models are inadequate for micro combustors because they were developed for analysis of regular scale combustor where heat loss can be ignored during the flame propagation. In this research a combustion model is proposed in order to estimate the heat loss and predict quenching limit of flame in a down scaled combustor. Heat loss in the burned region is expressed in a convective form as a product of wall surface area, heat transfer coefficient and temperature difference. Comparison to the measurements showed satisfactory agreement of the pressure and temperature drop. Quenching is accounted for by introducing a correlation of quenching parameter and heat loss. The present model predicted burnt fraction of gases with reasonable accuracy and proved to be applicable in thermal design of a micro combustor.

Effects of gas species on charging induced tungsten plug corrosion during post metal etch process have been investigated. It was found that the O2 plasma in the dry strip process induces considerable charge build-up, which subsequently results in the tungsten plug corrosion in the solvent with pH value larger than 4.0. Experiments were performed in various strip chambers in order to find effective methods to avoid the charging by the O2 plasma. Adding H2 or H2O to the O2 plasma during the strip process or additional H2O plasma treatment right after the O2 plasma strip process were proven to be an effective way to prevents the charge build-up by the O2 plasma. Mechanisms for the charge build-up by the O2 plasma and the drastic reduction of the charging by H-related compounds are discussed.

Summary form only given. In a gliding arc reactor, the arc string moves two dimensionally. On the other hand, in a rotating arc reactor the arc string moves three dimensionally by using a swirl motion of arc gas. This results in volumetric high-temperature environment, which is favorable for the thermal decomposition and oxidation reaction. For gaseous waste treatment, arc reactors should satisfy four conditions: 1) volumetric high-temperature region, 2) long electrode lifetime, 3) use of diverse reactant gases, and 4) high treatment efficiency. This study is focused on the electrode lifetime. The electrode lifetime working in air is compared among tungsten (W), zirconium (Zr), oxygen free copper (OFC), and copper-tungsten (Cu-W) alloy at the same flow rate (100 l/min) and power (15 kW). Temporal change in voltage-current values is monitored, and electrode weight loss and erosion shape are compared after 8 hr operation. Optimum material for long electrode lifetime is selected based on this experiment. With respect to the selected material, the erosion rate is further evaluated by varying the power.