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Autoclave is the most important equipment in the composite curing process, and its real-time condition has a direct impact on the quality of composite materials. Therefore, rapid and precise fault diagnosis reasoning is of great significance for the autoclave. To address the shortage of signed directed graph (SDG)-based fault diagnosis method, this paper proposes a fault diagnosis method based on digital twin (DT) enhanced SDG for autoclave. Firstly, the SDG model of autoclave temperature control system is constructed, and the model is improved and enhanced by pre-fault transition state identification, fuzzy confirmation of node states, and simplification of potential branch circuits by using DT. The effectiveness of the method in this paper is verified by fault diagnosis based on SDG and DT-SDG methods respectively. The experimental results show that the method proposed in this paper can improve the speed and resolution of fault diagnosis by reducing the number of potential fault propagation paths and the number of inferences. [ABSTRACT FROM AUTHOR]

This study optimised a novel autoclave-assisted Fe3O4 nanoparticle pre-treatment (NAAP) for the improvement of reducing sugar (RS) recovery from potato peel waste. The optimised NAAP was further assessed for other lignocellulosic substrates, recyclability, animal feed and bioethanol production. Maximum RS yield of 0.324 g/g was obtained with the optimised NAAP conditions. Recyclability resulted in an average RS yield of 0.254 g/g over three pre-treatment cycles. Moreover, the optimised NAAP for the pre-treatment of corn cob (0.021 g/g), cassava peels (0.242 g/g), bamboo stem (0.357 g/g), Amaranthus (0.428 g/g), sorghum leaves (0.867) and banana pseudostem (1.392 g/g) demonstrated its versatility. Furthermore, the potential of the optimised pre-treated biomass for animal feed waste valorisation and bioethanol production (22.82 g/L) was achieved. The present NAAP pre-treatment provides novel insights on the application of nanotechnology in lignocellulosic bioprocessing, which could eliminate chemical and enzyme usage, while reducing the process costs and its associated negative environmental impact. [ABSTRACT FROM AUTHOR]

Microgravity offers an enticing synthetic knob for materials scientists to explore—however, this environment creates major challenges in hardware development that can turn a simple 3-day experiment into a 3-year long nightmare. This paper provides an overview of engineering an autoclave, compatible with NASA's Solidification Using a Baffle in Sealed Ampoules (SUBSA) furnace, to enable microgravity hydrothermal synthesis—an acceleration-sensitive technique that processes aqueous samples above the boiling point of water. Hydrothermal synthesis is a universal chemical transformation technique that is used to produce a range of advanced materials with applications in alternative energy, healthcare, and the food industry. In this work, we use the synthesis of graphene hydrogel as a case study to verify our hardware design on Earth before launching to the International Space Station for microgravity testing. The design addresses pertinent challenges which include enabling thermal expansion while preventing air bubble formation in solution and implementing a pressure fail-safe above the maximum operating temperature. Our goal in presenting this autoclave design is to provide a step forward towards commercial-of-the-shelf microgravity hardware. [ABSTRACT FROM AUTHOR]

The method of chemical cleaning of the surface of blades of gas turbine units in a solution of orthophosphoric and sulfuric acids using a purpose-designed closed-type autoclave microwave system "Mars 5" and ultrasonic exposure in distilled water is described. The two-stage cleaning involves the chemical action of the acid solution in the autoclave and ultrasonic cleaning in the stage of washing. The effect of acid solutions of various concentrations on the degree of surface cleaning from metal oxides and microcracks in the gas turbine blades is studied. It is shown that when the samples of gas turbine blades are treated in the "Mars 5" autoclave with a solution of acids and with ultrasound in the washing stage, the residual oxygen content reflecting the presence of oxides on the surface of the samples is less than 1%. [ABSTRACT FROM AUTHOR]

Chlorella and Spirulina are the most used microalgae mainly as powder, tablets, or capsules. However, the recent change in lifestyle of modern society encouraged the emergence of liquid food supplements. The current work evaluated the efficiency of several hydrolysis methods (ultrasound-assisted hydrolysis UAH, acid hydrolysis AH, autoclave-assisted hydrolysis AAH, and enzymatic hydrolysis EH) in order to develop liquid dietary supplements from Chlorella and Spirulina biomasses. Results showed that, EH gave the highest proteins content (78% and 31% for Spirulina and Chlorella, respectively) and also increased pigments content (4.5 mg/mL of phycocyanin and 12 µg/mL of carotenoids). Hydrolysates obtained with EH showed the highest scavenging activity (95–91%), allowing us, with the other above features, to propose this method as convenient for liquid food supplements development. Nevertheless, it has been shown that the choice of hydrolysis method depended on the vocation of the product to be prepared. [ABSTRACT FROM AUTHOR]

Present investigation evaluated physicochemical and functional properties of Manila tamarind seed flour and seed protein isolate. Seed flour was defatted using petroleum ether (bp 40–60 °C) and used for preparation of protein isolate by alkaline extraction followed by isoelectric precipitation. Protein content in the seed flour was 32.59 ± 2.05% and 85.17 ± 0.31% in seed protein isolate. Protein isolates were treated with ultrasound (180W and 35 kHz) and autoclave (121℃ and 15psi) alone and in combination for 15 and 30 min, respectively. The autoclave treatment resulted in reduction of emulsification properties, protein solubility, and water and oil absorption capacity of the protein isolate but the same properties got enhanced with ultrasound treatment. Bulk density of samples increased with both treatments. The combination of treatments resulted in enhancement of all functional properties studied except bulk density and particle density. The values of protein solubility and water and oil absorption capacity of seed protein isolate increased from 64.11 ± 0.37% (native), 166.66 ± 2.51% (native), and 171.33 ± 1.52% (native) to 78.45 ± 1.04% (modified), 194 ± 1.73%, and 206 ± 4.00%, respectively, after autoclave and ultrasound treatments. Emulsifying activity and emulsion stability ranged between 56.47 ± 0.65% (native) to 78.19 ± 0.72% (modified) and 52.54 ± 0.80% (native) to 68.76 ± 0.81% (modified). SDS-PAGE pattern of the seed protein isolate (native and modified) revealed distinct dark bands between 50 and 90 kDa and certain fragmented bands in some of the modified samples. High molecular weight proteins were found to be stable towards the autoclave and ultrasound treatments, whereas low molecular weight proteins(~ 14–16 kDa and < 10 kDa) were slightly affected. [ABSTRACT FROM AUTHOR]

Dietary fiber (DF) is referred to be the "seventh fundamental nutrient," but the natural availability of soluble dietary fiber (SDF) in fruits and vegetables is minimal. So, the attempt is made to convert insoluble dietary fibers (IDF) into SDF from waste orange peels using micronization, autoclave, and a newly created hybrid approach that combines two technologies (autoclave followed by micronization). The goal of this study is to evaluate and enhance the nutritional, physicochemical, and other properties of DFs using micronization (mechanical comminution), autoclave (hydrothermal treatment), and hybrid approaches. Micronization, autoclave, and hybrid techniques successfully increased SDF from 4.71 to 10.16, 25.44, and 23.69%, respectively. SDF enhancement in micronization is rather low; however, the greatest growth is observed in physicochemical properties such as water and oil retention capacity and water swelling capacity. Life cycle assessment (LCA) was used to examine the environmental effect by different midpoint indicators of three processes for a lab size life cycle inventory. Global warming potential of the micronization process is relatively low compared to other two processes, i.e., 1.54 kg CO2 equivalent. Aside from that, crystallinity and morphological studies of soluble dietary fiber concentrate (SDFC) were carried out utilizing X-ray diffraction (XRD) and scanning electron microscopy (SEM). [ABSTRACT FROM AUTHOR]

This study compares the optimization of microwave-assisted (MW) and steam-assisted autoclave (AC) pretreatments of fig (Ficus carica) to produce fermentable sugar. The central composite design response surface method was used for the optimization of process parameters. The independent variables for MW were particle diameter of dried fig (Dp = 200–375 µm), pH (3.00–5.00), and power (P = 250–670 W); the variables for AC were particle diameter (Dp = 200–375 µm), pH (3.00–5.00), temperature (T = 95–120 °C), and time (t = 30–50 min). The dependent variable was total sugar concentration (TSC) upon hydrolysis. Statistical analysis of the observed TSC indicated that all MW pretreatment parameters were significant. However, the temperature was the only significant parameter affecting fig hydrolysis in AC. Regression coefficients between observed and predicted values were in good agreement for AC (R2 = 0.90) and MW (R2 = 0.88) indicating model strength to the experimental data. The sum of ranking method (SRM) was done to test the similarity of observed and predicted TSC within the studied ranges of the independent variables. The optimum conditions for maximum sugar concentration by MW were determined as Dp = 370.72 µm, pH 4.96, and P = 253.67 W with TSC = 82.9 g/L. AC conditions were Dp = 263.19 µm, pH = 3.02, T = 120 °C, and t = 30.00 min with maximum sugar concentration of 70.0 g/L. A validation experiment was also conducted on MW and AC models and a good agreement between model prediction and observed responses was observed. This study demonstrated the effectiveness of MW and AC as potential pretreatment options for fig hydrolysis to yield the high sugar concentration that can be used as a substrate for biofuel production. [ABSTRACT FROM AUTHOR]

The work describes a method for recovery of phosphorus compounds from phosphorus-containing raw materials. The possibility of autoclave leaching of phosphorus from phosphorite in the form of a solution of sodium phosphates with an alkaline solution was experimentally tested. The optimal process parameters were determined (temperature 250–300°C, leaching time 3 h, NaOH concentration 150–300 kg m–3), under which calcium silicate with a unique nano-sized needle-shaped structure, widely used in many industries, is formed in the solid residue. The research results make it possible to involve raw materials with low phosphorus content in waste-free processing. [ABSTRACT FROM AUTHOR]

Nowadays, composite materials are widely used in high-strength and low-weight parts, such as airborne structures, military equipment, and sports devices. Since most of the serpentine pipe parts have the requirements of one-piece forming and high strength, the material of serpentine pipe parts is still mainly metal. However, the parts cannot be easily separated from the metal molds after autoclave curing is always a difficult problem in the manufacturing process, which results in failed products. The autoclave process is often long and expensive. Therefore, improving its manufacturing yield rate is very important. To solve this problem, this study employs a ceramic lost foam mold to replace the metal mold used in the autoclave process. By adjusting parameters of autoclave and modifying the curing processes in different experiments and experienced several failed experiments, workable manufacturing processes and parameters are finally obtained such that the composite material made serpentine pipe parts are successfully produced. This study investigates the causes of failed products and corresponding solutions. Moreover, the current study executed process reproducibility experiments to verify the reproducibility of the proposed method. Experimental results determine workable manufacturing processes and parameters. The results not only facilitate the production of composite material made serpentine pipe parts but also significantly reduce the production cost and increase the throughput. [ABSTRACT FROM AUTHOR]

Reaction of 5-hydrazinyl-substituted 1,2,4-triazines and 2,5-norbornadiene at elevated pressure and temperature (in autoclave) has been studied; the reaction yields 2-aminopyridines, 5-amino-1,2,4,-triazines, and 6-unsubstituted pyridines (formation of one of two latter products is dependent on the nature of substituent in the C3 position of triazine). [ABSTRACT FROM AUTHOR]

Manufacturing of fiber reinforced polymer matrix composite materials is being done with various methods in recent days. But controlling the accuracy of manufacturing and begetting quality products is very challenging. Adopting single manufacturing techniques may not cater this purpose, but blended or unified technologies do. Artificial intelligence (AI) is an emerging technique that is highly reliable to be blended with current methods and caters to the needs of various composite manufacturers to the maximum possible extent. Accordingly, in this article, the primary focus is provided on the manufacturing sector and more particularly emphasis only on composite material manufacturing with the help of AI. The way the manufacturing is guided by digital technologies including AI is effective in terms of the quality of manufacturing composite materials. In most of the recent studies, AI techniques are used in autoclave manufacturing of composites to control temperature and pressure, curing of composites establishing control over the curing environment and also in flaw detection of composites. This article also focuses on using digital technologies for manufacturing simulation, hybridizing digital technologies and a few of its implications over Industry 4.0. [ABSTRACT FROM AUTHOR]

EVA is an important high-performance resin material obtained by the copolymerization of ethylene and vinyl acetate. In the present study, a comprehensive computational fluid dynamics (CFD) model was established to study the EVA free radical copolymerization process. The polymerization kinetic model was combined with the CFD model. The EVA copolymerization reaction mechanism was verified by comparing the simulation results with the experimental results. Detailed information of the flow field inside the industrial EVA autoclave reactor was obtained. With the increase of the impeller speed, both the axial and radial flows inside the autoclave reactor were enhanced. The high impeller speed improved the fluid mixing and the homogeneity of temperature distribution. The increase of the impeller speed improved the initiator dispersion near the inlets, thereby increasing the efficiency of the initiator. The influence of operating conditions on monomer conversion and specific initiator consumption per 1% of the monomer reacted was investigated. The simulation results give deep insight into the free radical copolymerization process inside the autoclave reactor and supply the guidelines for developing an industrial autoclave reactor. [ABSTRACT FROM AUTHOR]

Mine waters at the Reefton orogenic gold mine (active from 2007 to 2016) in southern New Zealand contained dissolved arsenic (As) and antimony (Sb) up to 5 mg/L during production of a sulfide concentrate that included arsenopyrite (FeAsS) and stibnite (Sb2S3). Ferric oxyhydroxide adsorption extracted As down to < 0.1 mg/L but dissolved Sb remained elevated due to adsorption competition with As. The Reefton sulfide concentrate was transported 700 km to the Macraes orogenic gold mine (active from 1990) for processing through a pressure oxidation autoclave at 225 °C. The Macraes ore has low Sb contents, so the temporary introduction of a Sb-rich component produced a short-term Sb signal in the autoclave system and tailings waters. Oxidation of stibnite occurred rapidly in the autoclave, in parallel with the As in the arsenopyrite, producing ferric antimonate (tentatively identified as As-bearing tripuhyite) and ferric arsenate (FeAsO4). Dissolved Sb in the Macraes tailings waters remained < 0.1 mg/L throughout the period of Reefton concentrate addition. The formation of tripuhyite in the high-temperature autoclave stabilised Sb in the Macraes tailings, so that dissolved Sb < As, in contrast to the low-temperature processes at Reefton where dissolved Sb > As. [ABSTRACT FROM AUTHOR]

Near-spherical niobium diboride nanoparticles with an average diameter of ~17 nm, crystallizing in the hexagonal system and belonging to the space group P6/mmm, were obtained by reacting NbCl5 with NaBH4 in ionic melts of alkali metal halides at 1073 K under an argon pressure of 4 MPa for 15 h in an autoclave. [ABSTRACT FROM AUTHOR]

The article presents a technique for process-induced residual strain modeling for thermoset composite material parts. The model takes into account the mechanical and thermal contact between the part and the mold. The technique is implemented in the ABAQUS software using user subroutines. Using the technique, it is possible to clarify the distribution of the heat transfer coefficient on the surface of the part and mold using the CFD method. Distribution of heat transfer coefficients are obtained in ANSYS CFX under the appropriate process conditions. The method is verified for the U-shaped sample. Also, the results of modeling the stringer-stiffened curved composite panel using the developed technique without taking into account the mold and heat transfer coefficient distribution are presented. [ABSTRACT FROM AUTHOR]

A majority of aircraft components are nowadays manufactured using autoclave processing. Essential for the quality of the component is the realization of an airtight vacuum bag on top of the component to be cured. Several ways of leakage detection methods are actually used in industrial processes. They will be dealt with in this paper. A special focus is put on a new approach using flow meters for monitoring the air flow during evacuation and curing. This approach has been successfully validated in different trials, which are presented and discussed. The main benefit of the method is that in case of a leakage, a defined limit is exceeded by the volumetric flow rate whose magnitude can be directly correlated to the leakage's size and position. In addition, the potential of this method for the localization of leakages has been investigated and is discussed. [ABSTRACT FROM AUTHOR]

Physical and chemical properties of Asian sea bass (Lates calcarifer) backbone subjected to high pressure heating (autoclaving, 121ºC) for different times (30 min; AT-30; 60 min; AT-60; 90 min; AT-90) were studied. As heating time augmented, the increases in protein, α-amino group and hydroxyproline contents in liquor were attained, while hardness was declined indicating that more organic compounds were leached out from the bone matrix. More pronounced XRD pattern was observed in backbone autoclaved for 90 min as a consequence of nano-hydroxyapatite crystals agglomeration. Extension of high-pressure heating time reduced the organic matters as elucidated by TGA and DTA data. Asian sea bass backbone heated at 121ºC for 90 min using autoclave had the lowered protein and lipid contents but increased ash content with highest calcium (29.65 ± 0.69%), phosphorus (15.80 ± 0.07%) and iron (15.10 ± 0.61 mg/kg) contents, compared to those with shorter heating time. Therefore, pre-heat treatment could reduce the organic compounds and decrease bone hardness for further process, especially for bio-calcium production. [ABSTRACT FROM AUTHOR]

Cure shrinkage of the polymer matrix during the composite manufacturing process leads to residual stresses, which can adversely affect the structural integrity and dimensional stability of composite structures. In this paper, a novel approach is developed for measuring the resin shrinkage and strain evolution of an epoxy resin (EPON-862) in the composite manufacturing environment. The resin is cured in a custom designed autoclave with borosilicate viewports, while digital image correlation (DIC) is used to analyze the strain evolution throughout the cure cycle. These processing induced strains are correlated to the cure-state using differential scanning calorimetery (DSC). The different mechanisms involved in the polymer strain evolution during composite processing are discussed. [ABSTRACT FROM AUTHOR]

An investigation of the effect of simultaneous thermal and mechanical loads on the compaction-creep-thickness recovery response of uncured prepreg system is essential to have a better understanding of the conditions applied during autoclave and out-of-autoclave processes. Compaction response mimics the mold closure effect, creep response mimics the dwell effect and thickness recovery response of the prepregs mimics the spring-back effect. However, there are almost no studies available to compare the void transport within prepregs for pristine (before compaction) and compacted (after spring-back) states using X-ray computed tomography (XCT) aided geometrical models. This study aims to analyze the thermo-mechanical compaction-creep-recovery response of 4- and 8-layers glass fiber uncured prepreg system. The target compaction pressures used were 0.1 and 0.3 MPa, applied at four different temperatures (25, 50, 80 and 100°C). The thickness of the specimens was measured at different time and based on these values, percentage of compaction, creep and permanent deformation were determined. XCT aided geometrical models were generated for the pristine and tested states to determine the void volume ratio and void counts. The decrease in thickness values at the target load is observed to be lower at 25°C than at 100°C, which confirms the higher initial compaction occurs at high temperatures. At room temperature, 4-layer specimens showed higher creep percentage at both pressures and offered more fibrous level changes compared to 8-layers. The creep percentage was found to decrease as the number of layers increased at low temperatures whereas the opposite trend was found at higher temperatures. Void maps indicated that friction between the fabric layers increases at higher temperatures (80 and 100°C) during resin bleed out which leads to low creep percentage in the 4-layer specimens as compared to 8-layer specimens. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to elucidate the effect of preheat-treatments and bleaching agents on molecular characteristics and bioavailability of obtained bio-calcium. Methods: Bio-calcium from Asian sea bass backbone was prepared using different preheat-treatment methods (boiling at 100 °C for 30 min or autoclaving at 121 °C for 90 min). Subsequent bleaching was carried out using 2.5% sodium hypochlorite, followed by 2.5% hydrogen peroxide or using 2.5% hydrogen peroxide alone. Results: Bio-calcium powder from autoclaved bone had higher calcium content (35.9 ± 0.2%) than that produced from boiled bone (25.7 ± 1.2%). Particle size of bio-calcium from autoclaved bone (16.71 ± 16.71 µm) was lower than that from boiled bone (52.85 ± 43.16 µm). Highest whiteness index (92.26 ± 0.21) was observed for autoclaved bone bio-calcium when hydrogen peroxide alone was used as bleaching agent. FTIR study confirmed that Ca-hydroxyapatite was present in both bio-calcium from boiled and autoclaved bones but the amount was higher in the latter. Conclusion: Boiling or boiling/autoclaving could be alternative pre-treatment for bio-calcium production to reduce chemical or alkali used and to soften the bone. However, solubility of autoclaved bone bio-calcium was lower than boiled bone counterpart. Enhancement of solubility is still needed to improve bio-availability of bio-calcium from Asian sea bass backbone. [ABSTRACT FROM AUTHOR]

8-Hydroxy(methoxy)-substituted 2-[6-(1-methylindol-3-yl)pyridin-2-yl]quinoline ligands were synthesized by means of combination of SNH reaction between 8-methoxy-substituted 2-(6-aryl-1,2,4-triazin-3-yl)quinolones and indole and aza-Diels–Alder reaction of the obtained 1,2,4-triazines with 2,5-norbornadiene. The demethylation of quinoline moiety of 1,2,4-triazine precursor during aza-Diels–Alder reaction in autoclave was demonstrated. [ABSTRACT FROM AUTHOR]

A new metal-organic framework {Zn4(BDC)3(OAc)2(DMF)4} (BDC = terephthalate anion) was synthesized under solvothermal conditions in a 3D-printed polypropylene autoclave. The product was isolated in a pure state and characterized by elemental analysis and X-ray diffraction (CIF file CCDC no. 2025811). The formation of this product, instead of the expected {Zn4O(BDC)3} (MOF-5), was probably due to a change in the conditions of solvothermal synthesis caused by disruption of the integrity of the polypropylene autoclave. This is a drawback of this method of screening of metal-organic frameworks, which, however, in some cases givs rise to new representatives of this class of crystalline materials. [ABSTRACT FROM AUTHOR]

For large composite parts manufactured by autoclave curing process, temperature uniformity of the mold is essential to ensure final part quality. This paper aims to investigate the influence of mold placement variation in autoclave on heating performance of a large framed mold and find the optimal mold placement parameters for improving the temperature uniformity and heating rate. Firstly, a computational fluid dynamics (CFD) based autoclave simulation model is established and validated, which offers reliable prediction of the mold temperature field and flow distribution in autoclave. Then, numerical experiments are performed based on the autoclave simulation model and response surface methodology (RSM) to establish relations between mold placement variables and responses including temperature uniformity and heating rate. Finally, using the established regression model, multi-objective optimization is conducted considering both temperature uniformity and heating rate. The optimal mold placement parameters are obtained successfully which improves the temperature uniformity significantly with little change in heating rate comparing to the commonly adopted mold placement approach. The strategies provided by mold placement optimization can be applied for various large framed molds in composite manufacturing improving the autoclave curing process. [ABSTRACT FROM AUTHOR]

In this study, boron nitride nanosheets (BN–NS) were prepared through exfoliation of bulk BN powder and efficacious incorporation of Ni (dopant material) was achieved using hydrothermal methodology. Hexagonal phase of BN (h-BN) was detected using x-ray difractometer (XRD). The presence of used chemicals was identified by functional group analysis through fourier transform infrared spectroscope (FTIR), which indicated strong vibrations for B–N and B–N–B. Optical examination carried out through absorption spectra extracted from UV–vis. spectroscopy point out absorption at deep UV state. Raman spectra were obtained to affirm structural molecular fingerprints of BN. Excitons behavior was studied using photoluminescence (PL) spectroscope. Scanning (SEM) and transmission electron microscopes (TEM) were used to investigate morphological and microstructural features while interlayer spacing was evaluated using HRTEM micrographs. Purity of the obtained product was studied by means of EDS analysis. Catalytic activity was undertaken to inspect dye degradation which was evaluated spectrophotometrically. This study provides experimental validation to the use of two-dimensional materials, especially BN–NS, for rapid and enhanced degradation of dyes. [ABSTRACT FROM AUTHOR]

We developed a set of in-situ Micro-Raman spectroscopy system for autoclave experimental apparatus because of the scientific significance of in-situ Micro-Raman spectroscopy system under the high-pressure hydrothermal condition. We used this system to measure the Raman spectrum of water-fluid and quartz crystal at the temperature ranging from 125 to 420 °C. The signal-to-noise ratio of the Raman signal is good. [ABSTRACT FROM AUTHOR]

The early Solar System comprised a broad area of abiotically created organic compounds, including interstellar organics which were integrated into planetesimals and parent bodies of meteorites, and eventually delivered to the early Earth. In this study, we simulated interstellar complex organic compounds synthesized by proton irradiation of a gas mixture of CO, NH3, and H2O, which are known to release amino acids after acid hydrolysis on the basis of Kobayashi et al. (1999) who reported that at the first stage of chemical evolution, the main compounds formed abiotically are complex organic compounds with high molecular weights. We examined their possible hydrothermal alteration and stabilities as amino acid precursors under high temperature and pressure conditions simulating parent bodies of meteorites by using an autoclave. We reported that all samples treated at 200–300 °C predominantly released glycine and alanine, followed by α-aminobutyric acid, and serine. After heating, amino acid concentrations decreased in general; however, the recovery ratios of γ-aminobutyric acid increased with temperature. The interstellar complex organic analog could maintain as amino acid precursors after being treated at high temperature (200–300 °C) and pressure (8–14 MPa). However, the molecular structures were altered during heating to form organic compounds that are more stable and can survive in elevated hydrothermal conditions. [ABSTRACT FROM AUTHOR]

Sugarcane cultivation is of great economic and social importance worldwide. In vitro cloning using temporary immersion systems is an option to produce vitroplants of high genetic and phytosanitary quality to establish stock seedbeds. However, the sterilization of culture media through autoclaving increases production costs and limits the efficiency of temporary immersion systems. For that reason, the objective of this study was to evaluate the morphological and physiological changes caused by Vitrofural® in sugarcane plants under temporary immersion. We compared two types of culture media sterilization: chemical sterilization using Vitrofural® and autoclaving using Temporary Immersion Bioreactors. After four weeks of cultivation, we evaluated morphological (number of shoots, shoot length, and number of leaves per shoot) and physiological indicators (soluble and bound phenolics, and phenolics excreted to the culture medium). As well as chlorophyll-a, -b and total chlorophyll content. The results show that when Vitrofural® was added to culture medium, a higher number of shoots per explant, length of the shoots and number of leaves were observed in comparison with the shoots obtained in autoclaved sterilized medium. Furthermore, a reduced the amount of phenolics compounds were found in Vitrofural® treatent.In addition, the use of the Vitrofural® increased the synthesis of photosynthetic pigments respect to autoclaving. In conclusion, Vitrofural® has a positive effect in morphological and physiological of sugarcane cultured in vitro and is a low-cost alternative for the commercial micropropagation of sugarcane. Key message: Vitrofural® produced a positive effect on the growth, content of photosynthetic pigments and compounds phenols during in vitro culture of sugar cane. [ABSTRACT FROM AUTHOR]

Background: Fused deposition modeling 3D printing is used in medicine for diverse purposes such as creating patient-specific anatomical models and surgical instruments. For use in the sterile surgical field, it is necessary to understand the mechanical behavior of these prints across 3D printing materials and after autoclaving. It has been previously understood that steam sterilization weakens polylactic acid, however, annealing heat treatment of polylactic acid increases its crystallinity and mechanical strength. We aim to identify an optimal and commercially available 3D printing process that minimizes distortion after annealing and autoclaving and to quantify mechanical strength after these interventions. Methods: Thirty millimeters cubes with four different infill geometries were 3D printed and subjected to hot water-bath annealing then immediate autoclaving. Seven commercially available 3D printing materials were tested to understand their mechanical behavior after intervention. The dimensions in the X, Y, and Z axes were measured before and after annealing, and again after subsequent autoclaving. Standard and strength-optimized Army-Navy retractor designs were printed using the 3D printing material and infill geometry that deformed the least. These retractors were subjected to annealing and autoclaving interventions and tested for differences in mechanical strength. Results: For both the annealing and subsequent autoclaving intervention, the material and infill geometry that deformed the least, respectively, was Essentium PLA Gray and "grid". Standard retractors without intervention failed at 95 N +/− 2.4 N. Annealed retractors failed at 127.3 N +/− 10 N. Autoclave only retractors failed at 15.7 N +/− 1.4 N. Annealed then autoclaved retractors failed at 19.8 N +/− 3.1 N. Strength-optimized retractors, after the annealing then autoclaving intervention, failed at 164.8 N +/− 12.5 N. Conclusion: For 30 mm cubes, the 3D printing material and infill geometry that deformed the least, respectively, was Essentium PLA and "grid". Hot water-bath annealing results in increased 3D printed model strength, however autoclaving 3D prints markedly diminishes strength. Strength-optimized 3D printed PLA Army-Navy retractors overcome the strength limitation due to autoclaving. [ABSTRACT FROM AUTHOR]

The known metal-organic framework {Zn4O(BDC)3} (MOF-5 (I), where BDC is terephthalate anion) is synthesized by the solvothermal method in autoclaves prepared by 3D printing from polypropylene. The synthesized polymer is isolated in the individual state and characterized by elemental analysis and powder X-ray diffraction analysis. The crystal structures of MOF-5 and another coordination polymer based on zinc(II) terephthalate {Zn4O(BDC)3} · (ZnO)0.125 (SUMOF-2 (II)) obtained as a by-product of the solvothermal synthesis are confirmed by X-ray diffraction analysis (СIF files ССDС nos. 1920366 (I) and 1926136 (II)). [ABSTRACT FROM AUTHOR]

Composite materials are demonstrating the ability to face the challenge of competitive markets where high-performance, low costs, and reduced manufacturing time are mandatory. Vacuum bagging with autoclave curing is one of the most used manufacturing methods for carbon fiber composite parts. However, it shows some limitations, mainly due to manual operations and long processing time. Out-of-autoclave (OOA) methods, such as pressure bag molding (PBM), can lead to a strong reduction of the manufacturing time through the simplification of lay-up and curing phases. In this paper, a comparative analysis between the autoclave and the PBM processes has been performed, jointly considering both the economic and environmental aspects. An evaluation of the environmental impacts has been carried out following the standardized life cycle assessment (LCA) methodology. In addition, costs related to these two manufacturing techniques have been estimated through a parametric approach and successively compared. Different scenarios have been considered to take into account various production batches, mold manufacturing techniques, and end of life alternatives. The analyses show conflicting results demonstrating that a global optimum scenario does not exist and, depending on the chosen indicator and production batch, the best alternative varies. Considering only the environmental indicators, the autoclave process can be considered the most sustainable option, due to the lower consumption of energy. [ABSTRACT FROM AUTHOR]

Silica sols modified with a silver compound are applied onto textile substrates to realize its antibacterial properties. As textile substrates, cotton fabrics are used. The liquid sol recipes are applied by a padding process onto the textiles. Afterwards, a microwave-assisted heating process is applied for drying of the silica sol coating and to form elementary silver nanoparticles. The microwave process is done in a closed autoclave system with process temperatures in the range of 80–140 °C. The process duration is only 5 min short, compared to traditional hydrothermal processes. The coating forming process is strongly determined by the applied process temperature, probably due to boiling and evaporation processes. Lower process temperatures and temperature development used lead to a regular distribution of the silica sol coating on the textile substrates. All prepared coated samples exhibit significant antibacterial properties against the bacteria S. aureus and E. coli. The antibacterial effectiveness increases as a function of silver content and with increasing process temperature of the microwave process. This first experimental set-up can act as first proof-of- concept for effective and fast functionalization of substrates by using microwave technology. Highlights: Direct formation of silver particles from silver nitrate on textile surfaces is possible during a microwave-assisted-solvothermal process. The developed process is of short process duration of only 5 min. With higher process temperature an irregular coating formation occurs related to fast boiling and evaporation processes during the microwave heating. The determined antimicrobial properties are significant. [ABSTRACT FROM AUTHOR]

Results of experiments on autoclave leaching of rare earth metals (REM) from hydroxide precipitate, obtained after alkaline atmospheric leaching ores of Tomtor deposit, are presented. It is established that autoclave leaching in the presence of oxygen makes it possible to increase the efficiency and selectivity of the process and to increase REM extraction by up to 10-13%. The main parameters of autoclave nitric acid leaching are as follows: initial HNO3 concentration 350 g/dm3; temperature 120°C; oxygen partial pressure 0.3 MPa; L:S = 5.0 (wt.); time 2 hours. In the optimum regime selected, 98.0-98.5% of REM is extracted into solution. [ABSTRACT FROM AUTHOR]

The present article concentrates on the fabrication of square tube by utilizing high strength carbon fabric epoxy resin prepreg through low cost pressure bag molding technique. In this process vacuum bag which was used has excellent expansion and high thermal stability. The manufactured carbon-epoxy prepreg square tube was evaluated on the basis of fiber volume fraction and mechanical properties such as longitudinal, transverse direction tensile strength. Further, carbon epoxy prepreg composite was manufactured by autoclave technique and compared the mechanical properties fabricated with pressure bag molding as square tube products can be obtained majorly by this technique. The results concluded that, the overall properties of composites manufactured by both the process are almost the same especially tensile strength. However, the specimens manufactured by pressure bag molding process have voids compared to the specimens manufactured by autoclave technique due to vacuum. Nonetheless, pressure bag molding technique can be satisfactorily considered to replace the autoclave technique molding technique and can eventually be applied to manufacture various industrial products such as yacht mast, bicycle frame, tennis racket etc. with low cost. [ABSTRACT FROM AUTHOR]

Due to the important scientific significance of the interaction between alkaline feldspar and high-temperature and high-pressure fluids. We have conducted a series of autoclave experiments of feldspar dissolution and secondary mineral precipitation in conditions of 250-500 °C, 8-50 MPa, and pH = 3.0 and 5.5. Based on the interaction experiments between alkaline feldspar and fluid of high-temperatures and high-pressures, we get the main results as follows: (1) The law that people have grasped below the critical point about the influence of temperature, pressure, and pH value on the alkaline feldspar dissolution behavior is still held above the critical point. (2) Due to the experimental techniques of autoclave flip 180°-sharp quenching and based on electron microprobe analysis of mineral new formed, theoretical analysis has determined that the new altered minerals distributed on the island dissolution surface of feldspar are products of precipitation on a feldspar surface after saturation of the relative ion concentration in water fluid. [ABSTRACT FROM AUTHOR]

Influence of stack structure on porosity of composite materials at different modes of autoclave molding was studied. To reduce porosity of composite materials, specific stack structure and molding mode are recommended. [ABSTRACT FROM AUTHOR]

A comparative study of the trends in ion exchange of NaX zeolite (molar ratio Si/Al = 1.34) pelletized without binder has been performed using successive treatment with calcium, lanthanum, and ammonium nitrate solutions at 80°C with intermediate calcination after each ion exchange stage or by ion exchange in an autoclave at 180°C with calcium nitrate and lanthanum and ammonium nitrate solutions without intermediate calcinations. It has been found that for the complete replacement of sodium cations in the zeolite framework (less than 1 wt % residual sodium oxide), a fourfold ion exchange at 80°C with vigorous stirring and intermediate calcinations or a twofold ion exchange at 180°C in an autoclave without intermediate calcinations is required. Comparison of the physicochemical and catalytic properties of the obtained catalyst samples with almost identical chemical composition has shown a significant advantage of ion exchange in the autoclave, since the zeolite retains its initial structural characteristics. [ABSTRACT FROM AUTHOR]

Ply thickness is one of the main drivers of the structural performance of a composite part. For stress analysis calculations (e.g., finite element analysis), composite plies are commonly considered to have a constant thickness compared to the reality (coefficients of variation up to 9% of the mean ply thickness). Unless this variability is taken into account reliable property predictions cannot be made. A modelling approach of such variations is proposed using parameters obtained from a 16-ply quasi-isotropic CFRP plate cured in an autoclave. A discrete Fourier transform algorithm is used to analyse the frequency response of the observed ply and plate thickness profiles. The model inputs, obtained by a mathematical representation of the ply thickness profiles, permit the generation of a representative stratification considering the spatial continuity of the thickness variations that are in good agreement with the real ply profiles spread over the composite part. A residual deformation FE model of the composite plate is used to illustrate the feasibility of the approach. [ABSTRACT FROM AUTHOR]

Nd-Fe-B permanent magnets doped with CuZn powders were prepared via conventional sintered method. The effects of CuZn contents on magnetic properties and corrosion resistance of the magnets were systematically studied. It shows that the remanence, coercivity, and maximum energy product decrease gradually with the increase in CuZn doping content. The magnet's corrosion kinetics in autoclaves environment and its electrochemical properties in electrolytes were also examined. It is interesting to see that the weight loss of 3.5 wt% and 4.5 wt% CuZn powders doping magnets is only 1 and 0 mg·cm after autoclaves test at 121 °C, 2 × 10 Pa for 500 h, respectively, which is much lower than that of the magnets without CuZn doping. Electrochemical results show that the CuZn powders doping magnets display more positive corrosion potential ( E ) and lower corrosion current density ( I ) than those of the original magnets without CuZn doping in sulphuric acid electrolyte and distilled water. It is, therefore, concluded that doping CuZn powders is a promising way to enhance the corrosion resistance of sintered Nd-Fe-B magnets. [ABSTRACT FROM AUTHOR]

The multiphase reaction process of pressure leaching is mainly carried out in the liquid phase. Therefore, gas holdup is essential for the gas-liquid-solid phase reaction and the extraction rate of valuable metals. In this paper, a transparent quartz autoclave, a six blades disc turbine-type agitator, and a high-speed camera were used to investigate the gas holdup of the pressure leaching process. Furthermore, experiments determining the effects of agitation rate, temperature, and oxygen partial pressure on gas holdup were carried out. The results showed that when the agitation rate increased from 350 to 600 r/min, the gas holdup increased from 0.10% to 0.64%. When the temperature increased from 363 to 423 K, the gas holdup increased from 0.14% to 0.20%. When the oxygen partial pressure increased from 0.1 to 0.8 MPa, the gas holdup increased from 0.13% to 0.19%. A similar criteria relationship was established by Homogeneous Principle and Buckingham's theorem. Comprehensively, empirical equation of gas holdup was deduced on the basis of experimental data and the similarity theory, where the criterion equation was determined as ε = 4.54 × 10 n T P . It can be seen from the formula that agitation rate made the most important impact on gas holdup in the pressure leaching process using the mixed-flow agitator. [ABSTRACT FROM AUTHOR]

Most of the resources used for energy have a fossil origin and they are non-renewable materials. Using mixtures of waste materials with the currently used non-renewable materials can improve the renewability of the energy production. The goal of this work was to explore the effect of waste tire addition on a hydrovisbreaking process at low temperature. Four tests were carried out at 300 °C in H with different feedstocks: (1) vacuum residue; (2) tires; (3) 37.5wt% tires + 62.5wt% vacuum residue; (4) 15wt% tires + 85wt% vacuum residue. Dynamic viscosity, simulated distillation, density, elemental analysis (C, H, N, S% content) by ICP and analysis of gaseous products by GC-MS were carried out for all products. Content of insoluble compounds in hexane was estimated for the products from test (1) and vacuum residue. TGA analyses of the tires were carried out. The addition of tires to the vacuum residue brought a positive effect to increasing the yield of lighter products in the final liquid product. Densities and composition determinated by elemental analyses were similar for feedstock and products. The dynamic viscosity (60 °C) decreased from 24,550 to 17,700 mPa s for test (1) and to 1640 mPa s for test (3). [ABSTRACT FROM AUTHOR]

A reaction of activated silicon with alcohols in an autoclave at 240-270 °C was studied. It was found that primary alcohols form tetraalkoxysilanes Si(OR) with high selectivity (up to 97%), while the secondary PrOH gave a mixture of compounds HSi(OPr), Si(OPr), HSi(OPr)OSi(OPr)H, HSi(OPr)OSi(OPr), and Si(OPr)OSi(OPr) with the predominance of trialkoxysilane (up to 67%). Carrying out the reaction under the indicated conditions has the advantage of experimental simplicity, reagent availability, high conversion of silicon, good isolated yields of products. [ABSTRACT FROM AUTHOR]

Radiochemically pure [ReX(CO)] ( X = Cl, Br, and I) were prepared for the first time by high-pressure carbonylation of ReO with carbon monoxide in an aqueous solution in the presence of halide ions at 210 °C. The complexes were isolated at the n.c.a. level from the reaction mixture by gas-phase transport with carbon monoxide at a high pressure. The procedure allows obtaining the target compounds in any appropriate solvent (aqueous and nonaqueous), which may open new synthetic prospects for the development of novel therapeutic radiopharmaceuticals. [ABSTRACT FROM AUTHOR]

The results of studying the structure and properties of composite ceramic coatings produced by microarc oxidation (MAO) on zirconium alloy E110 are presented. To form the coatings, a suspension electrolyte is used with the addition of aluminum-hydroxide nanopowder. It is shown that the addition of the nanopowder results in a substantial increase in the growth rate and thickness of the coating compared with coatings obtained in the same amount of time without the addition of nanopowder to the electrolyte. A decrease in the porosity of coatings with increasing time of microarc oxidation is also revealed. It is found that samples with MAO coatings have a greater resistance to corrosion in an autoclave as compared to uncoated samples. [ABSTRACT FROM AUTHOR]

Background: The increasing use of nanoparticles and nanocomposite in pharmaceutical and processed food industry have increased the demand for nontoxic and inert metallic nanostructures. Chemical and physical method of synthesis of nanostructures is most popular in industrial production, despite the fact that these methods are labor intensive and/or generate toxic effluents. There has been an increasing demand for rapid, ecofriendly and relatively cheaper synthesis of nanostructures. Methods: Here, we propose a strategy, for one-minute green synthesis of AgNPs and a one-pot one-minute green synthesis of Au-Ag nanocomposite, using Melia azedarach bark aqueous extract as reducing agent. The hydrothermal mechanism of the autoclave technology has been successfully used in this study to accelerate the nucleation and growth of nano-crystals. Results: The study also presents high antimicrobial potential of the synthesized nano solutions against common food and water born pathogens. The multistep characterization and analysis of the synthesized nanomaterial samples, using UV-visible spectroscopy, ICP-MS, FT-IR, EDX, XRD, HR-TEM and FE-SEM, also reveal the reaction dynamics of AgNO3, AuCl3 and plant extract in synthesis of the nanoparticles and nanocomposite. Conclusions: The antimicrobial effectiveness of the synthesized Au-Ag nanocomposite, with high gold to silver ratio, reduces the dependency on the AgNPs, which is considered to be environmentally more toxic than the gold counterpart. We hope that this new strategy will change the present course of green synthesis. The rapidity of synthesis will also help in industrial scale green production of nanostructures using Melia azedarach. [ABSTRACT FROM AUTHOR]

The article focuses on a study on the association of jarosite solid solution with arsenic-rich mine waters in the Macraes Mine in New Zealand. In the study, more than 100 samples of mineral scales were examined from the collected material. The mineral samples were examined and mineral content was determined by X-ray diffraction. Many samples contain minerals were hydrated.

Results are given for studying combined leaching of bauxite, bauxite cake, and sintering section electrostatic precipitator dust. Experiments are performed within the following limiting conditions: temperature 220-260°C, leaching time 30-90 min, return solution concentration 315-280 g/dm NaO. It is proven that alumina extraction into solution with combined leaching of bauxite, cake, and electrostatic precipitator dust is higher than with standard bauxite leaching by the Bayer process. A favorable effect is achieved due to forming alumino-ferruginous hydrogarnets during leaching. An increase in leaching temperature makes it possible to improve alumina leaching under stable uniform conditions. [ABSTRACT FROM AUTHOR]

In the present study, an attempt has been made to recover autoclave heat by exploiting the pyrite oxidation in presence of sodium carbonate during alkali leaching of lean grade uranium ore. From the studies it was observed that feed to the auto calve contains about 1.6 % pyrite and heat evolved during the exothermic reaction was controlled by modification of heat recovery circuit. From this modification, it was possible to maintain a self-sustaining temperature at 140 °C in the autoclave without any external heating. [ABSTRACT FROM AUTHOR]

The object of investigation is an autoclave cake of the refractory gold-containing flotation concentrate prepared using a pilot plant. The influence of heat treatment (HT) on the chemical composition and recovery of gold is investigated for this material in a temperature range of 100-500°C. Due to the HT, it is possible to acquire high recovery of gold up to 98%. This is attained due to deep removal during the HT of organic carbon, which passivated gold during the autoclave oxidation. Arsenic is situated in a stable nontoxic form of iron arsenate, which undergoes no variations in the content and remains in the cake at the HT stage throughout the temperature range under study. The possibility in principle to process the double refractory concentrate with the help of a complex technology of autoclave oxidation and subsequent HT is shown. [ABSTRACT FROM AUTHOR]

Removal of pathological lesions from the mandible can leave a disfiguring appearance in addition to compromising the function of speech and mastication. It therefore becomes imperative to replace the lost part with bone grafts. Autogenous bone grafts-vascularised and non-vascularised, have been in vogue for the same. The probability of using the same resected bone after removal of all pathology has been done for a long time with mixed results in terms of uptake and viability. This paper presents a case of the use of autoclaved resected bone being used for reconstructing the mandible. [ABSTRACT FROM AUTHOR]