Search

The fabrication of freestanding bendable films without polymer substrates is demonstrated as a capacitive humidity-sensing material. The bendable and porous SiO2/Si films are simply prepared by electrochemical-assisted stripping, metal-assisted chemical etching, followed by oxidation procedures. The capacitive humidity-sensing properties of the fabricated porous SiO2/Si film are characterized as a function of the relative humidity and frequency. The remarkable sensing performance is demonstrated in the wide RH range from 13.8 to 79.0%. The sensing behavior of the porous SiO2/Si film is studied by electrochemical impedance spectroscopy analysis. Additionally, the reliability of the porous SiO2/Si sensing material is confirmed by cyclic and long-term sensing tests.

This paper describes steering returnability by analyzing forces applied to kingpin axis in limit cornering conditions. The steering returnability is related to forces applied to kingpin axis. These forces are classified by its source: Tire force and steering force. Tire force is generated from tire such as longitudinal, lateral, vertical force, and residual self-aligning torque. Steering force consists of friction force and assist force. These forces are vectorized by suspension geometry and calculated with respect to kingpin axis. The simulation results are compared with measurement data and verifies that steering returnability can be formulated by tire forces and steering forces. Using these relations, this paper proposes new steering control logics at limit driving conditions. This logic is verified by simulation model to check performance and confirmed in various test conditions for robustness.

The extremely thermophilic eubacterium Fervidobacterium islandicum AW-1 produces low molecular weight (LMW; < 1 kDa) keratin peptides (KPs) from poultry feathers at 70°C. However, detection and quantification of feather hydrolysate-derived peptides is needed for optimizing fermentation and down-stream processes. Herein, we developed a large-scale fermentation and purification of skin anti-aging LMW KPs from recalcitrant feathers using fluorescence-based quantification of N-terminal prolinecontaining KPs derivatized with 3,4-dihydroxybenzoic acid to yield fluorescent adducts. Fluorescent products were correlated with bioactive KP concentrations in keratin fractions and cosmetic formulations. Subsequent anaerobic fermentative keratinolysis and large-scale purification achieved 4.4 g/L LMW KPs from 8 g/L native feathers in a 5 L batch bioreactor, generating 0.8 g/L purified MMP-1 suppressive KPs (yield = 1.2%). This demonstrated the feasibility of industrial-scale anaerobic feather digestion and purification of LMW KPs to produce skin anti-aging peptides from keratin hydrolysates in a more environmentally sustainable manner.

Electric arc furnace oxidizing slag (EOS), in the fine aggregate form, can effectively be utilized as a construction material. However, its engineering properties vary with the manufacturing processes employed and the producing district, thereby causing observed differences in material performance. In this study, EOS was obtained from steel manufacturing plants in South Korea, and engineering properties of standalone EOS, as well as in combination with cement mortar were separately evaluated. Test results demonstrate that EOS primarily comprises CaO, SiO2, and FeO in combination with 18.2% larnite, which possesses β-C2S crystal structure with a similar cement mineral. The EOS mortar combination demonstrated increasing compressive strength with an increase in EOS content due to the effect of a considerable amount of β-C2S present in EOS. The EOS-based mortar with electric arc furnace reduction slag (ERS) demonstrated unsatisfactory results in accordance with a criterion set for the length rate of change. This implies that more consideration is required toward the use of mixed ERS and EOS in cement mortars due to the swelling effect of ERS on dimensional stability.

Calcined hwangtoh is a pozzolanic material that is increasingly being used as a mineral admixture in the concrete industry. This study shows a hydration model for cement–hwangtoh blends and evaluates the various properties of hwangtoh-blended concrete using reaction degrees of binders. First, a kinetic reaction model is proposed for analyzing the pozzolanic reaction of hwangtoh. The reaction of hwangtoh includes three processes: the initial dormant period, boundary reaction process, and diffusion process. The mutual interactions between the binary reactions of cement and hwangtoh are thought to be in line with the items in capillary water and calcium hydroxide. Second, the reaction degrees of cement and hwangtoh are determined based on a blended hydration model. Furthermore, the chemical (chemically combined water and calcium hydroxide contents), mechanical (compressive strength), thermal (hydration heat), and durability aspects (carbonation depth) of hwangtoh-blended concrete are systematically predicted. The results show good agreement with experimental results.

The transversely isotropic behaviour of thermal sprayed aluminium and zinc coating has been investigated based on a combination of nanoindentation experimental data and microporomechanics theory. A recently developed strength homogenisation approach comprises of the solid and porous medium is adopted to investigate the morphology properties of thermal sprayed aluminum and zinc coating. The finding of this paper demonstrates that the individual aluminum and zinc phases in the coating have a characteristic packing density close to the theoretical highest spherical packing ratio for face-centred cubic and hexagonal close packed. Also, the plasticity properties of solid particles in both aluminum and zinc are found to have a significant transversely isotropic condition, while the elasticity properties are close to isotropic. These findings led to the conclusion that the anisotropic condition of the coating is dominantly affected by the plasticity properties, in terms of cohesion and friction coefficient.

In this study,Al–Zn and Al–Mg coatings were deposited on steel substrates by an arc thermal spray process.X-ray diffraction and scanning electron microscopy were used to characterize the deposited coatings and corrosion products.Open circuit potential（OCP）,electrochemical impedance spectroscopy,and potentiodynamic studies were used to assess the corrosion characteristics of these coatings after exposure according to the Society of Automotive Engineers（SAE）J2334 solution of varying durations.This solution simulates an industrial environment and contains chloride and carbonate ions that induce corrosion of the deposited coatings.However,the Al–Mg alloy coating maintained an OCP of approximately-0.911 V versus Ag/Ag Cl in the SAE J2334 solution even after 792 h of exposure.This indicates that it protects the steel sacrificially,whereas the Al–Zn coating provides only barrier-type protection through the deposition of corrosion products.The Al–Mg coating acts as a self-healing coating and provides protection by forming Mg6Al2（OH）16CO3（Al–Mg layered double hydroxides）.Mg6Al2（OH）16CO3has interlocking characteristics with a morphology of plate-like nanostructures and an ion-exchange ability that can improve the corrosion resistance properties of the coating.The presence of Zn in the corrosion products of the Al–Zn coating allows dissolution,but,at the same time,Zn5（OH）6（CO3）2and Zn6Al2（OH）16CO3are formed and act to reduce the corrosion rate.

A new technique was accepted to fill the porosity of Al coating applied by arc thermal spray process to enhance corrosion resistance performance in artificial ocean water. The porosity is the inherent property of arc thermal spray coating process. In this study, applied coating was treated with different concentrations of ammonium phosphate mono basic (NH4H2PO4: AP) solution thereafter dried at room temperature and kept in humidity chamber for 7d to deposit uniform film. The corrosion resistance of Al coating and treated samples have been evaluated using electrochemical impedance spectroscopy (EIS) and potentiodynamic techniques with exposure periods in artificial ocean water. Electrochemical techniques, X-ray diffraction (XRD), Raman spectroscopy, atomic force microscopy (AFM) and field emission-scanning electron microscopy (FE-SEM) indicated that phosphate ion would have been retarding corrosion of Al coating effectively. The formation of AHP (Ammonium Aluminum Hydrogen Phosphate Hydrate: NH4)3Al5H6(PO4)8.18H2O) on Al coating surface after treatment with AP is nano sized, crystalline and uniformly deposited but after exposure them in artificial ocean water, they form AHPH (Aluminum hydroxide phosphate hydrate Al3(PO4)2(OH)3(H2O)5) that is very protective, adherent, uniform and plate like morphology of corrosion products. The AHPH is sparingly soluble and adherent to surface and imparted improved corrosion resistance.

Concrete contains cement, which is known to emit large amounts of CO2 in production, absorbs a certain amount of CO2 by triggering a carbonation reaction with atmospheric CO2. However, this CO2 absorption is generally neglected when evaluating the CO2 emission from concrete. Thus, it is necessary to discover and consider ways to quantitatively evaluate the CO2 absorbed by concrete. To this end, a carbonation model that can accurately predict the carbonation depth of concrete is necessary. However, the existing carbonation prediction equation is a simple regression equation that merely considers factors such as water–cement ratio and CO2 concentration, and has a drawback as the results vary considerably form one researcher to another. Meanwhile, currently the use of fly ash, which is effective in reducing both of hydration heat and CO2 emission and enhancement of long-age strength, is increasing. Thus, in the present study, a method for measuring CO2 absorption by fly-ash-blended concrete structures using a carbonation model based on fly-ash-blended hydration was developed and evaluated. An apartment complex in which fly-ash-blended concrete was used is evaluated for its CO2 absorption by using the developed method in this study. As a result, carbonation depth, amounts of CO2 emission and absorption of fly-ash-blended concrete structure by design strength was obtained. The CO2 absorbed by service life is approximately 3.79–8.47 % of the CO2 emitted during the manufacturing of the concrete structure.

Simvastatin is an inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, which catalyzes the conversion of HMG-CoA to mevalonate, an early and rate-limiting step in the biosynthesis of cholesterol. Simvastatin has good permeability, but it also has low solubility (BCS class II), which reduces its bioavailability. To overcome this problem, a solid dispersion is formed using a spray-dryer with polymeric material carrier to potentially enhance the dissolution rate and extend drug absorption. As carriers for solid dispersion, Gelucire(R) 44/14 and Gelucire(R) 50/13 are semisolid excipients that greatly improve the bioavailability of poorly-soluble drugs. To avoid any toxic effects of an organic solvent, we used aqueous medium to melt Tween(R)80 and distilled water. The structural behaviors of the raw materials and the solid dispersion were analyzed by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM). The DSC and PXRD data indicated that the crystalline structure of simvastatin was transformed to an amorphous structure through solid dispersion. Then, solid dispersion-based tablets containing 20 mg simvastatin were prepared with excipients. Dissolution tests were performed in distilled water and artificial intestinal fluid using the USP paddle II method. Compared with that of the commercial tablet (Zocor(R) 20 mg), the release of simvastatin from solid dispersion based-tablet was more efficient. Although the stability study is not complete, this solid dispersion system is expected to deliver poorly water-soluble drugs with enhanced bioavailability and less toxicity.

Finding an alternative fuel and reducing environmental pollution are the main goals for future internal combustion engines. Hydrogenmethane (HCNG) is now considered an alternative fuel due to its low emission and high burning rate. An experimental study was carried out to obtain fundamental data for the combustion and emission characteristics of pre-mixed hydrogen and methane in a constant volume chamber (CVC) with various fractions of hydrogen-methane blends. A pre-mixed chamber was used to obtain a good mixture of these gases. Exhaust emissions were measured using a Horiba exhaust gas analyzer for various fractions of hydrogen-methane blends. The results showed that the rapid combustion duration was shortened, and the rate of heat release elevated as the hydrogen fraction in the fuel blend was increased. Moreover, the maximum mean gas temperature and the maximum rate of pressure rise also increased. These phenomena were attributed to the burning velocity, which increased exponentially with the increased hydrogen fraction in the fuel blend. Exhaust HC and CO2 concentrations decreased, while NOX emission increased with an increase in the hydrogen fraction in the fuel blend. Our results could facilitate the application of hydrogen and methane as a fuel in the current fossil hydrocarbon-based economy and the strict emission regulations in internal combustion engines.

Granulated slag from metal industries and fly ash from the combustion of coal are among the industrial by-products and have been widely used as mineral admixtures in normal and high strength concrete. Due to the reaction between calcium hydroxide and fly ash or slag, compared with Portland cement, the hydration of concrete containing fly ash or slag is much more complex. In this paper, by considering the producing of calcium hydroxide in cement hydration and the consumption of it in the reaction of mineral admixtures, a numerical model is proposed to simulate the hydration of concrete containing fly ash or slag. The heat evolution rate of fly ash or slag blended concrete is determined from the contribution of both cement hydration and the reaction of mineral admixtures. Furthermore, a temperature rise in blended concrete is evaluated based on the degree of hydration of cement and mineral admixtures. The proposed model is verified with experimental data on the concrete with different water-to-cement ratios and mineral admixtures substitution ratios.

This study was carried out to investigate quantitatively the relationship between the degree of reinforcement corrosion and the mechanical properties of reinforcement. In the experiment, the tensile test of corroded reinforcement was conducted at different stage of reinforcement corrosion. As a result, it was found that the chloride-induced corrosion caused the pitting and the corrosion using electrical current caused the uniformed corrosion. As the degree of reinforcement corrosion increased, the nominal yield point and nominal elastic modulus decreased. Also, there were very high correlations between the degree of reinforcement corrosion and the mechanical properties of reinforcement. We could make the material constitutive laws for the mechanical properties of reinforcement as a function of the degree of corrosion. Also, it is possible to analyze the strength of damaged RC members with reinforcement corrosion using constitutive laws of reinforcement by the FEM.

Silica fume (SF) has been used since long as a mineral admixture to improve durability and produce high strength and high performance concrete. Due to the pozzolanic reaction between calcium hydroxide and silica fume, compared with ordinary Portland cement, the carbonation of concrete containing silica fume is much more complex. In this paper, based on a multi-component concept, a numerical model is built which can predict the carbonation of concrete containing silica fume. The proposed model starts with the mix proportions of concrete and considers both Portland cement hydration reaction and pozzolanic reaction. The amount of hydration products which are susceptible to carbonate, such as calcium hydroxide (CH) and calcium silicate hydrate (CSH), as well as porosity can be obtained as associated results of the proposed model during the hydration period. The influence of water-binder ratio and silica fume content on carbonation is considered. The predicted results agree well with experimental results.

For larger proteins, and proteins not amenable to expression in bacterial hosts, it is difficult to deduce structures using NMR methods based on uniform (13)C, (15)N isotopic labeling and observation of just nuclear Overhauser effects (NOEs). In these cases, sparse labeling with selected (15)N enriched amino acids and extraction of a wider variety of backbone-centered structural constraints is providing an alternate approach. A limitation, however, is the absence of resonance assignment strategies that work without uniform (15)N, (13)C labeling or preparation of numerous samples labeled with pairs of isotopically labeled amino acids. In this paper an approach applicable to a single sample prepared with sparse (15)N labeling in selected amino acids is presented. It relies on correlation of amide proton exchange rates, measured from data on the intact protein and on digested and sequenced peptides. Application is illustrated using the carbohydrate binding protein, Galectin-3. Limitations and future applications are discussed.

Using a high degree of automation, the Southeast Collaboratory for Structural Genomics (SECSG) has developed high throughput pipelines for protein production, and crystallization using a two-tiered approach. Primary, or tier-1, protein production focuses on producing proteins for members of large Pfam families that lack a representative structure in the Protein Data Bank. Target genomes are Pyrococcus furiosus and Caenorhabditis elegans. Selected human proteins are also under study. Tier-2 protein production, or target rescue, focuses on those tier-1 proteins, which either fail to crystallize or give poorly diffracting crystals. This two tier approach is more efficient since it allows the primary protein production groups to focus on the production of new targets while the tier-2 efforts focus on providing additional sample for further studies and modified protein for structure determination. Both efforts feed the SECSG high throughput crystallization pipeline, which is capable of screening over 40 proteins per week. Details of the various pipelines in use by the SECSG for protein production and crystallization, as well as some examples of target rescue are described.