Autoclave Method Research Articles

Surface modification of fumed silica by photo-dimerization reaction of cinnamyl alcohol and cinnamoyl chloride

The surface modification of silica particles by an organic functional group has been intensively studied, and the modified structure can be analyzed by various experiments and simulations. Cinnamyl alcohol and cinnamoyl chloride are well known for their photo-dimerization reactions. By introducing them on the fumed silica surface, it is possible to create a functional silica which can be aggregated by cross-linking under optical irradiation. For surface modification of the fumed silica, an autoclave method was used with the cinnamyl alcohol, while the reflux method was used for the cinnamoyl chloride. Fourier Transform Infrared Spectroscopy (FT-IR), a thermogravimetric analysis (TG) and the Bruneuer–Emmett–Teller (BET) method were used to evaluate the surface structure of the modified silica. In the case of modification with cinnamyl alcohol, the maximum amount of the modifier groups was 1.7-OR/nm2, and the modification degree could be controlled by varying the initial concentration of the modifier in the reaction. On the other hand, the maximum amount of the modifier groups was 0.33-OR/nm2 with cinnamoyl chloride, but it could be increased to 0.69-OR/nm2 when pyridine was used as the catalyst during the modification. The reaction process was evaluated by the MOPAC simulation, and the ultraviolet (UV) absorption based on the structure was calculated by ZINDO. In the photo-irradiation experiment, which used an extra high pressure mercury lamp as a spectral source, it was confirmed that the modifier on the silica surface formed α and β-dimer, the structure of which was decided by the intermolecular distance. In this study, it was confirmed that the cross-linking occurs on interparticle based on the results of the simulation and measurement of the UV absorption. However, a moderate density of the modifier is essential for initiating the interparticle cross-linking.

Получение стержневых структур карбида кремния капельным и автоклавным методами

Preparation of silicon carbide by traditional methods involves considerable energy and economic costs, so the search for alternative technologies of the synthesis is of the great interest. Carbon nanomaterials are actively investigated as a carbon source to reduce the temperature of synthesis. This paper presents the results of an experimental study of the morphology, elemental composition and crystal structure of structures obtained from colloidal solutions of short (l ~ 500 nm) carbon nanotubes and nano-sized (~ 7 nm) amorphous silicon dioxide by drying droplet and autoclave methods. The formation of rod-like structures was revealed at certain critical concentrations of initial components. It was found that the dynamic conditions of the drying droplets determine a synthesis of rod-like structures at room temperature at 2-3 times larger than at the autoclave at a temperature of about 180 °C. The elemental analysis of samples showed a high percentage of carbon and silicon atoms. The presence of the polytype 4-H SiC phase in the rod-like structures was revealed by the X-ray diffractometry. A model of the active charged center of short carbon nanotubes that provides the possibility of Si-C, Si-O-C and C-Si-O-C covalent bonds formation was offered based on numerical calculations. The drying droplet method is suitable for a quick (10-20 minutes) local synthesis of a small amount of rod-like structures with a minimum energy consumption. The autoclave allows to synthesize gram quantities for a long time (a few days). Both methods are low temperature in the comparison with the widely used in practice.

Evaluation of Mechanical and Physical Properties of Clinically Used and Recycled Superelastic NiTi Wires.

The initial leveling and aligning phase has been simplified with the introduction of superelastic nickel-titanium archwires. The relatively high cost of these wires has prompted some of the clinicians to reuse them after sterilization. The quantitative changes in the surface properties of superelastic 'NiTi' wires after clinical application and recycling by autoclave method have not been established in earlier studies. To quantify the changes in mechanical and physical properties of four different commercially available superelastic nitinol (NiTi) archwires after clinical usage and recycling. The superelastic 'NiTi archwires obtained from four different manufacturers: Group I-GAC (McMinnville, USA); Group II- 3M Company (California, USA); Group III- G&H Company(Franklin, USA) and Group IV- American Orthodontics (AO) (Sheboygan, USA) were selected for the study. Each of the four groups comprised of 20 samples of wire with 10 of them selected randomly as control and remaining 10 as test specimen in each group. The experimental archwires were placed on selected patients for a period of three months followed by Standard Autoclave sterilization at 121°C and 15 to 20 psi pressure for 20 minutes and were retrieved. The tensile strength was evaluated by Instron-Universal Testing Machine. The quantification of changes in surface roughness was investigated by grid method using Scanning Electron Microscope (SEM). The Control Wires (C) were evaluated at initial time "T1" where as the Experimental sample of wires (T) were subjected to testing at an initial time 'T1' and after clinical usage and sterilization at 'T2'. Paired t-test was used for intra-group comparison and one way ANOVA and Post Hoc Tukey tests were used for inter-group comparison. There was significant decrease in tensile strength (p = 0.0015 to 0.001) and surface roughness (p< 0.001) between control and experimental arch wires within each group when properties at T1 and T2 were compared. The study suggests discouraging the use of clinically used and sterilized superelastic NiTi archwires.

THE EFFECT OF MICROWAVE, AUTOCLAVE AND HOT AIR OVEN STABILIZED WHEAT BRAN SUBSTITUTION ON NUTRITIONAL AND SENSORIAL PROPERTIES OF FLAT BREADS

The influence of stabilized wheat bran enrichment on the nutritional and sensorial properties of leavened and unleavened flat bread was studied. Wheat bran was stabilized with three applications (hot air oven, microwave and autoclave). The stabilization methods affected the physical characteristics of bazlama (thickness, spread factor) and yufka (diameter, thickness, spread factor) samples. In bazlama samples, substitution of stabilized wheat bran (SWB) lead to significant decrease in L* and increase in a* and b* values compared to the control bazlama. While autoclave and microwave stabilization methods are the most effective methods to decrease the phytic acid content for bazlama samples, for yufka samples; autoclave stabilization is the best. The mineral content (Ca, K, Mg, Mn, P, Fe and Zn) of bazlama and yufka samples significantly (p<0.05) increased with SWB substitution. Thus, autoclave stabilization could be used for wheat bran stabilization to improve the nutritional quality of bazlama and yufka samples.

Flight Test of Composite Speed Brake Manufactured by Out of Autoclave Methods. ―Flight Test Results and Cost Evaluation―

Flight Test of Composite Speed Brake Manufactured by Out of Autoclave Methods. ―Flight Test Results and Cost Evaluation―

Controlling microbial contamination during hydrolysis of AFEX-pretreated corn stover and switchgrass: effects on hydrolysate composition, microbial response and fermentation.

BackgroundMicrobial conversion of lignocellulosic feedstocks into biofuels remains an attractive means to produce sustainable energy. It is essential to produce lignocellulosic hydrolysates in a consistent manner in order to study microbial performance in different feedstock hydrolysates. Because of the potential to introduce microbial contamination from the untreated biomass or at various points during the process, it can be difficult to control sterility during hydrolysate production. In this study, we compared hydrolysates produced from AFEX-pretreated corn stover and switchgrass using two different methods to control contamination: either by autoclaving the pretreated feedstocks prior to enzymatic hydrolysis, or by introducing antibiotics during the hydrolysis of non-autoclaved feedstocks. We then performed extensive chemical analysis, chemical genomics, and comparative fermentations to evaluate any differences between these two different methods used for producing corn stover and switchgrass hydrolysates.ResultsAutoclaving the pretreated feedstocks could eliminate the contamination for a variety of feedstocks, whereas the antibiotic gentamicin was unable to control contamination consistently during hydrolysis. Compared to the addition of gentamicin, autoclaving of biomass before hydrolysis had a minimal effect on mineral concentrations, and showed no significant effect on the two major sugars (glucose and xylose) found in these hydrolysates. However, autoclaving elevated the concentration of some furanic and phenolic compounds. Chemical genomics analyses using Saccharomyces cerevisiae strains indicated a high correlation between the AFEX-pretreated hydrolysates produced using these two methods within the same feedstock, indicating minimal differences between the autoclaving and antibiotic methods. Comparative fermentations with S. cerevisiae and Zymomonas mobilis also showed that autoclaving the AFEX-pretreated feedstocks had no significant effects on microbial performance in these hydrolysates.ConclusionsOur results showed that autoclaving the pretreated feedstocks offered advantages over the addition of antibiotics for hydrolysate production. The autoclaving method produced a more consistent quality of hydrolysate, and also showed negligible effects on microbial performance. Although the levels of some of the lignocellulose degradation inhibitors were elevated by autoclaving the feedstocks prior to enzymatic hydrolysis, no significant effects on cell growth, sugar utilization, or ethanol production were seen during bacterial or yeast fermentations in hydrolysates produced using the two different methods.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-015-0356-2) contains supplementary material, which is available to authorized users.

소독멸균 방법에 따른 초음파 스케일링 팁에 부착된 세균의 양상

Objectives: The purpose of the study was to investigate the bacterial morphology attached on ultrasonic scaler tips using no cleansing solution, alcohol cotton, liquid chemical disinfecting agent, and autoclave method. Methods: Scaling tip was applied to the mouth and the ultrasonic scaler tips were assigned to four groups. Group 1 was control group with no cleansing solution. Group 2 was treated with alcohol cotton. Group 3 was treated with 2% green Y-Na solution in liquid chemical disinfecting agent, and Group 4 was sterilized by autoclave method. Live bacteria were observed by phase contrast microscopy. The scanning electron microscopy(SEM) revealed the morphological characteristics of scaler surface. The type of attached bacteria were analyzed using SPSS 21.0 program. The data were analyzed by one-way analysis of variance(ANOVA) and Tukey's post-hoc test. Results: The types of sterilization methods had influences on the bacterial viability. The numbers of cocci, bacilli, spiral form bacteria, and filamentous bacteria was observed in <TEX>$89.00{\pm}3.60%$</TEX>, <TEX>$29.67{\pm}3.51%$</TEX>, <TEX>$3.33{\pm}0.57%$</TEX> and <TEX>$1.67{\pm}0.57%$</TEX> in control group, <TEX>$31.67{\pm}3.51%$</TEX>, <TEX>$63.33{\pm}4.04%$</TEX>, <TEX>$2.00{\pm}1.00%$</TEX> and <TEX>$1.67{\pm}0.57%$</TEX> in alcohol cotton group, <TEX>$69.67{\pm}4.50%$</TEX>, <TEX>$12.33{\pm}2.51%$</TEX>, 0% and 0% in liquid chemical disinfecting agent group, and 0.0%, 0.0%, 0.0% and 0.0% in autoclave method group. The clean surface of ultrasonic scaler tip was shown on SEM by autoclave method. Conclusions: The most effective sterilization method of ultrasonic scaler tip was the autoclave method. Autoclave method is the most effective sterilization method and can reduce the cross-infection in the dental clinic.

The effect of graphene oxide and its oxidized debris on the cure chemistry and interphase structure of epoxy nanocomposites

The influence of graphene oxide (GO) and its surface oxidized debris (OD) on the cure chemistry of an amine cured epoxy resin has been investigated by Fourier Transform Infrared Emission Spectroscopy (FT-IES) and Differential Scanning Calorimetry (DSC). Spectral analysis of IR radiation emitted at the cure temperature from thin films of diglycidyl ether of bisphenol A epoxy resin (DGEBA) and 4,4'-diaminodiphenylmethane (DDM) curing agent with and without GO allowed the cure kinetics of the interphase between the bulk resin and GO to be monitored in real time, by measuring both the consumption of primary (1°) amine and epoxy groups, formation of ether groups as well as computing the profiles for formation of secondary (2°) and tertiary (3°) amines. OD was isolated from as-produced GO (aGO) by a simple autoclave method to give OD-free autoclaved GO (acGO). It has been found that the presence of OD on the GO prevents active sites on GO surfaces fully catalysing and participating in the reaction of DGEBA with DDM, which results in slower reaction and a lower crosslink density of the three-dimensional networks in the aGO-resin interphase compared to the acGO-resin interphase. We also determined that OD itself promoted DGEBA homopolymerization. A DSC study further confirmed that the aGO nanocomposite exhibited lower Tg while acGO nanocomposite showed higher Tg compared to neat resin because of the difference in crosslink densities of the matrix around the different GOs.

Enhanced Anti-inflammatory Effects of γ-irradiated Pig Placenta Extracts.

Porcine placenta extract (PPE) is known to possess anti-inflammatory properties owing to its high concentration of bioactive substances. However, the need to eliminate blood-borne infectious agents while maintaining biological efficacy raises concerns about the optimal method for sterilizing PPE. Therefore, the objective of this study was to compare the effects of the standard pressurized heat (autoclaving) method of sterilization with γ-irradiation on the anti-inflammatory effects of PPE. The anti-inflammatory actions of these two preparations of PPE were evaluated by measuring their inhibitory effects on the production of NO, the expression of iNOS protein, and the expression of iNOS, COX2, TNF-α, IL-1β, and IL-6 mRNA in lipopolysaccharide-stimulated RAW 264.7 cells. Compared with autoclaved PPE, γ-irradiated PPE showed significantly greater inhibition of NO production and iNOS protein expression, and produced a greater reduction in the expression of iNOS, COX2, TNF-α, IL-1β, and IL-6 mRNA. These results provide evidence that the sterilization process is crucial in determining the biological activity of PPE, especially its anti-inflammatory activity. Collectively, our data suggest that γ-irradiated PPE acts at the transcriptional level to effectively and potently suppresses the production of NO and the expression of pro-inflammatory cytokines.

Synthesis and Characterization of Ca and Na Zeolites (Non-Pozzolanic Materials) Obtained From Fly Ash–Ca(OH)2 Interaction

Abstract The conventional method for alkali activation of fly ash utilizes Ca(OH)2 and NaOH for the formation of pozzolanic material and fly ash zeolites, respectively. Sodium-based fly ash zeolites (say, Na-zeolite) mostly employ NaOH (the high-grade mineralizer and alkali) for activation of fly ash before its application as an absorbent. However, the Na-zeolites as absorbents (in agro- and aqua-culture) result in sodicity (i.e., excess of Na, present as impurity in the zeolite), which in turn reduces their holding capacity of moisture, nutrient [i.e., nitrogen, phosphorous, and potassium (NPK fertilizers)], microorganisms (viz., microbial spores), or heavy metals and negatively affect the growth of plant and aquatic life. To resolve such problems, the present study is focused on synthesis of agro-grade blend (dominated by Ca-zeolite) of zeolites by using Ca(OH)2 as major alkali and two well-established mineralizers, NaOH and NaCl, used in the trace quantity. To monitor activation of the fly ash in two different conditions, the synthesis of zeolites could be carried out by employing (1) conventional (the open hydrothermal system), and (2) autoclaving (the closed hydrothermal system) methods. The main attributes that control the entire study include temperature and reaction times for both methods. In addition, the present study demonstrates (1) effectiveness of Ca(OH)2 in creation of blend of zeolites with considerable cation exchange capacity when an optimum chemical composition (comparable to a pure agro- and aqua-grade zeolite 4A), and (2) suitability of the conventional hydrothermal method over autoclave method in synthesizing the blend of Ca- and Na-zeolites possessing a cation exchange capacity up to 394 meq/100 g. The formation of needle/star/spherule/small cube-shaped crystals (i.e., Na-P1, the Na-zeolite) and prismatic/cuboidal shaped crystals (i.e., heulandite, the Ca-zeolite), confirms suitability of the end product as a good sorbent and manure.

Effect of Microwave and Conventional Autoclave Post-Curing on the Mechanical and Micro-structural Properties of Particulate Reinforced Polymer Matrix Composites

The application of polymer matrix composites has found valuable in many engineering fields like electrical, marine, aerospace, electronics and microelectronics. Thus, a new technique like microwave through electromagnetic energy was explored for processing of polymer matrix composite. The roles of microwave in the post curing of polymer matrix composites cannot be underestimated, as it has the capacity to improve the mechanical and micro-structural properties of the composite produced. The aim of the study is to investigate the effect of microwave post curing on the mechanical and micro-structural properties of particulate reinforced polymer matrix composites. These effects were compared with composites post cured using conventional autoclave oven with the objective of investigating the significance of microwave curing on the tensile strength and structural qualities in terms of defects of the produced composites. A specific study comprising of aluminum filled polyester based composite and carbon black filled polyester based composite were investigated using two different composite curing methods (microwave oven and conventional autoclave oven). The investigation, through experimentation was based on mechanical property (tensile strength) and micro-structural quality (defects) of the produced composites. Comparing the results of the post-curing of the composites using microwave and conventional methods, there is direct relationship between the tensile strength and the percentage weight fraction of the fillers with respect to the post curing methods. 30% aluminium filled, post cured in microwave has 0.01 MPa tensile strength, 20% aluminium filled (microwave) has 0.0076MPa while 30% aluminium filled (conventional oven curing) has 0.0092MPa and 20% aluminium filled (conventional oven curing) has 0.0068MPa. Also, composites post-cured with microwave show less voids defect compared to that post-cured by conventional autoclave oven. It was shown in this paper that post-curing of the particulate composites through microwave was able to improve the tensile strength and minimize defects better as compared to conventional autoclave method.

306 データ同化を利用したCFRPの加熱硬化状態の推定

Recently, with the aim of low cost and high cycle "out-of-autoclave method" is proposed. However, since out-of-autoclave method of forming a vacuum pressure, imperfect moldings such as voids are likely to occur. Therefore, compared to the autoclave method, it is quite inferior in terms of the molding quality. In the past, the smart manufacturing technique has been studies to perform efficient molding by forecasting the molding state using the numerical simulation based on the information obtained by monitoring the molding process. But there is a problem that the modeling quality is degraded by the sensors embedded in the interlaminar of CFRP. In this study, by using data assimilation technique to integrate the forecast value by numerical simulation with the observed value by measurement, we constructed the model state estimation technique with high accuracy and we proposed that the technique of estimating the internal state of CFRP without embedding a sensor. In this technique, we estimate the whole internal temperature distribution of CFRP from observed values of the surface of CFRP by using an ensemble kalman filter, which is one of data assimilation techniques. In addition, we confirmed that the thermal conductivity distribution could be estimated simultaneously.

Comparism of Cure Modeling of Unsaturated Polyester Based Composites Using Microwave and Autoclave Assisted Hand Lay-Up Process in Cylinderical Mould

Modeling of composite curing process is required prior to composite production as this would help in establishing correct production parameter and method of curing thereby eliminating costly trial and producing an effective method of curing a particular polymeric composite. The main objective of this work is to compare the difference between modeled microwave and conventional autoclave heating methods in producing polyester-aluminum and polyester- carbon black composites. This will establish the effectiveness of a curing method in the production of a particular polymer composite i. e, prediction of best possible trends during microwave and conventional autoclave heating with regards to effect of heating rate on degree of cure of the composites. The numerical models were constructed by taking into account heat transferred by electromagnetic energy (microwave) and heat transferred by conduction (conventional autoclave) through the resin/filler mixture, as well as kinetic heat generated by cure reaction. The numerical solution of the mathematical models presented were discretized using forward finite differences of the RungeKuta method and finally solved using MATLAB® Computer programming language. It was observed that curing of the samples was achieved faster in microwave than conventional autoclave method as microwave heat transfer by electromagnetic energy produces volumetric heat flow as compared to conventional autoclave whose heat transfer by conduction generates transverse heat flow to the samples. This implies that in the production process of polymer-matrix composites, electromagnetic energy through microwave was able to produce faster heating rate; thus, an effective method of curing in the production process of polymer-metal composites.

3D SCANNING INSPECTION OF THE COMPOSITE STRUCTURES

Wide range of different visual measurement techniques, which are used nowadays, shows the need of the development of geometry description possibilities. New applications of advanced materials require measurement methods, which can be used in the areas of reverse engineering, FEA modelling validation, rapid prototyping and analysis of structure deformations. Light and laser-based techniques such as photogrammetry, laser triangulation, Moire and optical coherence tomography allow for analysing geometry of the specimens. Widely used optical methods take into account the global and local coordinate translation, sensitivity, resolution, and measurement uncertainty. They are used in the respect to research trends such as direct shape measurement from surfaces, system calibration and optimization methods. In this paper, composite specimens’ geometries with artificial delamination inside and structures without delamination are analysed. Rectangular, curved and cylindrical shapes are investigated by 3D scanning technique. The measured composite structures are manufactured with autoclave and vacuum bag methods. Results presented in this paper, shows geometries different between composites manufactured by using these methods. Inspection process was executed in two steps. First, virtual models of the composite specimens are used to determine main geometry dimensions. Second, their curvatures and GD&T are determined. Additional, the thickness change connected with delamination is revealed. Used method gives an opportunity of observing specimens curving radius and manufacturing defects. Presented results shows that use of additional aluminum plate in vacuum bag method allowed to get specimens with high level of flatness and parallelism in the case of rectangular structures and cylindricity in case of the curved shells. Presented methodology of the inspection is simply, give multidimensional results and its application are not limited to laboratory conditions.

Synergetic reduction of graphene oxide by sodium hydroxide and microwave irritation

Graphene oxide was prepared by a modified Hummers method in a Teflon-lined autoclave and then reduced by two different approaches. Alkaline reduction by sodium hydroxide as the control and synergetic reduction which combined sodium hydroxide and microwave irritation were conducted. The products were characterised by transmission electron microscopy, X-ray diffraction, thermo-gravimetric analysis, Fourier transform infrared spectroscopy and by atomic force microscopy. Results showed that the synergetic method possessed higher efficiency. Moreover, the as-prepared samples were monolayers (about 0.8 nm) and could decrease the solubility of ethyl cellulose in ethanol.

Feasibility of stabilizing expanding property of furnace slag by autoclave method

Furnace slag was stabilized in an autoclave environment and then transformed into a mortar bar for the autoclave test. The expansion capacity of the slag mortar bar was observed to evaluate the feasibility of stabilizing slag expansion through the autoclave method. Results showed that the pretreatment of furnace slag by autoclave method is effective in stabilizing slag. The required time for stabilizing furnace slag is related to the property of the slag itself. Slag is completely stabilized when the expansion capacity of the slag mortar bar does not exceed 0.052% after three hours of autoclave at 215.7°C.

α-Fe2O3/Graphene Nanocomposite as Anode Material for Sodium-Ion Batteries with Enhanced Capacity Retention

Among the different energy storage systems, rechargeable lithium-ion batteries (LIBs) have been widely applied in various portable electronic devices due to their high energy densities, long cycle life, and lack of significant memory effect [1]. For wide-scale implementation of renewable energy, LIBs, however, face challenges related to their safety, lifetime, and cost. Based on the wide availability and low cost of sodium, sodium-ion batteries (SIBs) have the potential for meeting the demands of large-scale and sustainable applications. Many cathode materials have been proposed, whereas only a few anode materials have been investigated for SIBs [2]. The sodium ion (1.02 Å) has a larger ionic radius than the lithium ion (0.76 Å), so that graphite cannot be used as anode for SIBs [3]. There is less choice of anode materials for SIBs. Transition metal oxides have been investigated as possible negative electrodes, relying on insertion of Na+ at low voltages. Valvo et al. reported that the electrochemical sodiation of nanostructured Fe2O3 is reversible with the voltage range of 0.05-3.0 V vs. Na+/Na, and its specific capacity is 350 mAh g-1 over 30 cycles at 40 mA g-1 [4, 5]. Fe2O3 requires further modifications, however, to overcome its limitations for SIBs, such as poor electronic conductivity, volume variations, and related cycling issues. To improve the electronic conductivity and capacity retention, we prepared α-Fe2O3/Graphene nanocomposite using the ultrafast and environmentally friendly microwave autoclave method [6].The α-Fe2O3/Graphene nanocomposite was analysed by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) to determine their morphology and structural properties. Graphene contents in the composites were determined by thermogravimetric analysis (TGA). α-Fe2O3 nanoparticles are embedded in conductive and interconnected graphene networks [Fig 1(a)]. This nano-architecture increases the electronic conductivity and buffers volume change in α-Fe2O3/Graphene nanocomposite electrode. It can be observed in the XRD pattern in Fig. 1 that the α-Fe2O3/Graphene nanocomposite has more broad peaks than the α-Fe2O3 [Fig 1(b)]. The electrochemical results show that the composite electrode containing 10 wt.% graphene has higher initial capacity recovery (69 %) than the pure Fe2O3 electrode (59 %) [Fig 1(c)] [4]. Moreover, the composite shows better capacity retention than in the reported results in the literature, retaining 401 mAh g-1 at current density of 40 mA g-1 after 30 cycles in the range of 0.05-2.60 V vs. Na+/Na [Fig 1(d)] [3, 4].

Green synthesis, characterization and catalytic activity of palladium nanoparticles by xanthan gum

Here, we report the synthesis, characterization and catalytic evaluation of palladium nanoparticles (PdNPs) using xanthan gum, acting as both reducing and stabilizing agent without using any synthetic reagent. The uniqueness of our method lies in its fast synthesis rates using hydrothermal method in autoclave at a pressure of 15 psi and at 120 °C temperature by 10 min time. The formation and size of the PdNPs were characterized by UV–visible spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy. The catalytic activity of PdNPs was evaluated on the reduction of 4-nitrophenol to 4-aminophenol by sodium borohydride using spectrophotometry.

Tetradecanol/expanded graphite composite form-stable phase change material for thermal energy storage

Natural flake graphite was chemically intercalated to prepare expandable graphite. The expandable graphite was then expanded by means of microwave irradiation to obtain expanded graphite (EG). Tetradecanol (TD)/EG composite form-stable phase change materials (PCMs) were prepared by mixing TD with EG through an autoclave method. The highest loading of TD in the composite form-stable PCMs with good form-stability was 93wt%. The composite form-stable PCMs exhibited excellent thermal energy storage capacity. The melting enthalpy (ΔHm) and crystallization enthalpy (ΔHc) of the composite form-stable PCM containing 93wt% TD were 202.6 and 201.2J/g, respectively. However, the solid–solid phase transition of TD in the composite form-stable PCMs was hindered as TD was strongly absorbed by EG. As a result, the ΔHm and ΔHc of the composite form-stable PCMs were slightly lower than the theoretical value. The thermal conductivity of the composite form-stable PCMs was greatly enhanced by EG and was increased with the increasing of EG loading. The thermal conductivity of the composite form-stable PCM containing 7wt% EG attained 2.76W/mK. Besides, effects of the prepared EG on properties of the composite form-stable PCMs were compared with those of EG derived from commercially obtained expandable graphite.

가압가열 및 Microwave 처리가 생면의 품질에 미치는 영향

Abstract This study was conducted to determine the effects of physical treatments for quality of wet noodles. Noodles were being tried with a microwave (for 1 min), an autoclave (for 30 or 50 min), and both autoclave and microwave (for 30/1 min or 50/1 min). The results showed that the pH levels were slightly decreased after treatments of autoclave and autoclave/ microwave. The moisture contents were considerably decreased as compared to the control except autoclave (50 min). After all treatments, the lightness was decreased in all samples, but, redness was increased (except microwave) and the yellowness was increased after autoclave (50 min) and autoclave/microwave (50/1 min). Texture was increased as compared to the control except microwave. In the sensory evaluation, the noodles treated with microwave, autoclave (50 min), and autoclave/ microwave (50/1 min) showed a high score in overall preference. From these results, both the autoclave and microwave methods can be applied to the wet noodles without diminishing its quality to a great extent. Key words: autoclave, microwave, noodle, quality