Applications In Various Industrial Fields Research Articles

Application of Flux Method to the Fabrication of Ba5Ta4O15, Sr5Ta4O15, Sr2Ta2O7, and BaTaO2N Polycrystalline Films on Ta Substrates

The fabrication of high-quality crystal layers has been an active research topic in the field of modern materials chemistry with potential applications in various industrial fields. In particular, photocatalytic water splitting, in which hydrogen and oxygen molecules are directly dissociated from water using solar energy and visible-light-driven photocatalysts, is a potentially economical and green process for producing clean and renewable hydrogen energy. In this work, films of three crystalline oxides, Ba5Ta4O15, Sr5Ta4O15, and Sr2Ta2O7, and one crystalline oxynitride, BaTaO2N, were grown using the flux-coating technique in molten chloride salts (flux) at 1000 °C. The film growth was studied under several different conditions. In particular, we investigated the effect of three different atmospheres (air, nitrogen, and ammonia) on the growth behavior and composition of the polycrystalline layers grown from a BaCl2·2H2O flux. We found that the growth atmospheres were important in forming idiomorphic cryst...

Synthesis and characterization of a furan-based self-healing polymer

The extensive researches of self-healing polymer have been carried out for various applications in industrial fields. In this research, bio-based self-healing polymer was prepared using a cross-linking mechanism between polybutylene furanoate (PBF) and bismaleimide (BM) by Diels-Alder reactions, and it was blended with bio-based polyurethane (BPU) to improve the liquidity, elasticity, and mechanical properties. These self-healing polymer and BPU blended elastomer were made with different ratios of PBF, BM, and BPU. PBF-BM polymer has 6:1, 8:1, and 10:1 of PBF: BM ratios. Each polymer and BPU constitutes self-healing elastomer with 1:1, 1:1.5, and 1:2 ratios. Properties and self-healing ability of these elastomers were investigated by thermal, mechanical, and morphological analysis. On average, 6:1 of PBF: BM ratio shows the outstanding self-healing efficiency and 1:2 of PBF-BM polymer: BPU ratio has the highest mechanical properties with maintain its self-healing ability. Overall results indicated that BPU is a good reinforcement of the furan-based self-healing polymer with improving the self-healing ability and eco-friendly performance. Open image in new window

Brazilian Dioscoreaceas starches

Determination of the characteristics of native starches is crucial in order to select their best application in various industrial fields. Thus, two different types of non-traditional native starches from the Dioscoreaceas species (Dioscorea sp. and Dioscorea piperifolia Humb. var. Wild) were studied regarding their thermal, structural and rheological properties. The results were contrasted with traditional commercial starch sources (potato, cassava and corn). From the thermogravimetric results (TG/DTG), D. piperifolia starch obtained the highest thermal stability of the samples, except for potato starch. Furthermore, using differential scanning calorimetry and viscoamylograph profiles (RVA), it was found that the Dioscoreaceas starches presented a higher onset (To) temperature and susceptibility to retrogradation. They also showed lower values in relation to relative crystallinity, which was calculated from their X-ray patterns and tendency to white (L*) colour. The shapes of the Discoreaceas starch granules were determined using electron microscopy; it was found that as the potato starch the Dioscoreaceas starches showed a wide range of particle size.

Frequency control of sol–gel composite films fabricated by stencil printing for nondestructive testing applications

Ultrasonic transducers made of sol–gel composites have been developed for nondestructive testing (NDT) applications in various industrial fields. Stencil printing of sol–gel composite films has been developed for the reduction of fabrication time and cost. However, it was necessary to develop low frequency (<10 MHz) ultrasonic transducers for inspecting industrial structures under severe high-temperature conditions, because high-frequency components suffer attenuation effect caused by high temperature. To realize this, increasing the thickness of Pb(Zr,Ti)O3 (PZT)/PZT films fabricated by stencil printing was attempted in this study. The samples were fabricated by single-layer stencil printing with a thick stencil mask and multilayer pure stencil printing with prespraying and postspraying. The film thicknesses were 150–185 µm, and the center frequencies of ultrasonic responses were 6.0–6.4 MHz. Throughout three thermal cycles of up to 370 K, the ultrasonic performance was stable, and the frequency characteristics were not markedly different from the beginning to the end of the test. Therefore, low-frequency ultrasonic transducers were successfully manufactured using a stencil-printing-based technique.

Evaluation of toxicity and biodegradability of choline chloride based deep eutectic solvents

Deep eutectic solvents (DESs) have been dramatically expanding in popularity as a new generation of environmentally friendly solvents with possible applications in various industrial fields, but their ecological footprint has not yet been thoroughly investigated. In the present study, three choline chloride-based DESs with glucose, glycerol and oxalic acid as hydrogen bond donors were evaluated for in vitro toxicity using fish and human cell line, phytotoxicity using wheat and biodegradability using wastewater microorganisms through closed bottle test. Obtained in vitro toxicity data on cell lines indicate that choline chloride: glucose and choline chloride:glycerol possess low cytotoxicity (EC50>10mM for both cell lines) while choline chloride:oxalic acid possess moderate cytotoxicity (EC50 value 1.64mM and 4.19mM for fish and human cell line, respectively). Results on phytotoxicity imply that tested DESs are non-toxic with seed germination EC50 values higher than 5000mgl−1. All tested DESs were classified as′readily biodegradable′ based on their high levels of mineralization (68–96%). These findings indicate that DESs have a green profile and a good prospect for a wider use in the field of green technologies.

Synthesis and characterization of polysulfone based on poly(ethylene terephthalate) waste

The recycling process of Poly(ethylene terephthalate) (PET) wastes is commercially important since it converts a waste material into a value‐added product and also helps to alleviate environmental pollution. PET waste was depolymerized in the presence of ethylene glycol and manganese acetate as a catalyst. Bis(hydroxyethyl terephthalate), (BHET) and other oligomers are predominately the glycolyzed products (GP). These GP products were reacted with a prepared dichlorodiphenylsulfone (DCDPS) in presence of dried potassium carbonate. Two polysulfones (A &amp;B) with different number average molecular weights, 1787 and 3162 g/mol. were obtained, respectively. The chemical structures of the resulting two polysulfones were elucidated using 1HNMR and characterized by the known conventional analysis techniques (e.g. FTIR, GPC, DSC, TGA…). The prepared polysulfone (B) disclosed higher thermal stability with respect to the initial reactants. The originality of this study was derived from the use of waste materials to yield a product that has acceptable high thermal stability which provide many beneficial applications in various industrial fields. POLYM. ENG. SCI., 55:1671–1678, 2015. © 2014 Society of Plastics Engineers

Synthesis of Amphiphilic Polymers Based on Fatty Acids and Glycerol‐Derived Monomers – A Study of Their Self‐Assembly in Water

Amphiphilic polymers are synthesized from various biobased compounds involving telomerization of glycerin‐derived acrylate monomers with mercaptan‐modified fatty acids. The effects of the chemical structure of the saturated or unsaturated hydrophobic block are investigated. Dynamic and static light scattering measurements, transmission electronic microscopy, and atomic force microscopy observations show that these copolymers are capable of self‐assembling into nanosized spherical particles in aqueous solution, made from compound micelles. The critical micellar concentration of these polymers is in the range of 10–60 mg L−1 determined by fluorescence. These biobased polymers could have applications in various industrial fields, such as cosmetics and agrochemicals. image

Screening and Xylanase Production by Streptomyces sp. Grown on Lignocellulosic Wastes

Xylanases have raised interest because of their potential applications in various industrial fields, including the pulp and paper industries, bioethanol production, and the feed industry. In bioethanol production from lignocellulosic compounds, xylanase can improve the hydrolysis of cellulose into fermentable sugars, since the xylan restricts the cellulases from acting efficiently. In this work, a new thermophilic Streptomyces sp. was selected for its ability to produce xylanase. Carbon source selection is an important factor in the production of hemicellulases. The highest activity was obtained when Streptomyces sp. I3 was grown in the presence of wheat bran. Xylanase activity was partially characterized concerning the effect of pH and temperature on activity and thermostability, and the effects of different metal ions were also tested. The pH and temperature profile showed optimal activity at pH 6.0/70 °C. Zymogram analysis showed multiple xylanases (39, 21, 18, and 17 kDa). Xylanases studied in this work are thermophilic, thermostable, and active in a wide pH range; they have potential to be used in the development of new processes of biotechnological interest.

Poly(ester‐amine) hyperbranched polymer as toughening and co‐curing agent for epoxy/clay nanocomposites

AbstractThe marriage between hardness and flexibility of epoxy resins (improved toughness) is a desired feature, which broads their application in various industrial fields, especially for high impact resistance purposes. Accordingly, this work aims to improve toughness properties of epoxy resin (Epon‐828)/Ancamine (curing agent) system using amino‐terminated hyperbranched poly(ester‐amine) [Poly(PEODA‐NPA)] (HP) as toughening and/or co‐curing agent, in presence of organo‐modified Montmorillonite clay (OMMT) as a reinforcing filler. HP was synthesized via Michael addition reaction of poly(ethylene glycol) diacrylate (PEODA) to N‐methyl‐1,3‐propanediamine (NPA). Chemical structure and molecular weight of HP were elucidated using infrared (FTIR) spectroscopy and gel permeation chromatography (GPC) techniques, respectively. Epoxy/OMMT nanocomposites toughened with HP (at different concentrations) showed remarkable improvement in their toughness without any adverse effect on the other physico‐mechanical properties. The optimum concentration of HP and OMMT was found to be 20 wt % and 1–3 wt% of the epoxy resin, respectively. The extent of exfoliation and dispersion of OMMT platelets within the epoxy cured films was assessed by X‐ray diffraction (XRD) and transmission electron microscopy (TEM) measurements. In addition, thermal gravimetric analyses (TGA‐DTA) of epoxy/OMMT nanocomposites toughened with HP showed a slight increase in their decomposition temperature, particularly at low OMMT loading. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

Trends in Particle Formation of Bioactive Compounds Using Supercritical Fluids and Nanoemulsions

This review discusses the recent developments in the application of supercritical fluid technologies for the production of composites or encapsulates of bioactive compounds. Various supercritical particle formation technologies are briefly described, including processes in which the supercritical fluid acts as a solute, solvent, and antisolvent. The main features and mechanisms of antisolvent techniques that contribute to the understanding of the fundamentals of the Supercritical Fluid Extraction of Emulsions (SFEE) process are described. The published literature on SFEE, including the results and perspectives of its application in various industrial fields, are discussed. This article is the first comprehensive review specifically focused on the formation of particles using the SFEE technique.

Superhydrophobic surfaces fabricated by surface modification of alumina particles

The fabrication of superhydrophobic surfaces has attracted intense interest because of their widespread potential applications in various industrial fields. Recently, some attempts have been carried out to prepare superhydrophobic surfaces using metal oxide nanoparticles. In the present work, superhydrophobic surfaces were fabricated with low surface energy material on alumina particles with different sizes. It was found that particle size of alumina is an important factor in achieving stable superhydrophobic surface. It was possible to obtain alumina surface with water contact angle (WCA) of 156° and a sliding angle of <2°. Superhydrophobicity of the modified alumina is attributed to the combined effect of the micro-nanostructure and low surface energy of fatty acid on the surface. The surface morphology of the alumina powder and coatings was determined by FESEM. The stability of the coatings was assessed by conducting water immersion test. Effect of heat treatment on WCA of the coating was also studied. The transition of alumina from hydrophilic to superhydrophobic state was explained using Wenzel and Cassie models. The method is shown to have potential application for creating superhydrophobic surface on cotton fabrics.

New Biological Functions and Applications of High‐Molecular‐Mass Poly‐γ‐glutamic Acid

Ultra-high-molecular-weight poly-gamma-glutamic acid (gamma-PGA) is a most promising biodegradable polymer that is produced by Bacillus subtilis (chungkookjang). Attractive properties of gamma-PGA are that it is water soluble, anionic, biodegradable, and edible. Development of gamma-PGA has pursued in terms of cosmetics/skin care, bone care, nanoparticle for drug delivery system, hydrogel, and so on. Very recently, our research has shown that gamma-PGA can be used as an immune-stimulating agent, especially at high molecular weight. This review presents the synthesis and production of high-molecular-weight gamma-PGA and its various applications in industrial fields.

Effect of infrared pulsated laser on the dielectric properties of polycarbonate

Makrofol-De polycarbonate is a class of polymeric solid state nuclear track detector which has many applications in various industrial fields. A study of the modification possibility of the dielectric properties of a Makrofol polymer using laser irradiation has been carried out. In the present work, Makrofol samples were irradiated using different fluences between 0.47 and 10.4 J/cm2 of 5 W infrared laser. The modifications in the laser irradiated Makrofol samples have been studied as a function of fluence using dielectric constant ϵ′, dielectric loss ϵ″, and AC conductivity σAC measurements. The frequency dependencies (100 Hz–5 MHz) of ϵ′, ϵ″ and σAC at 35 °C were investigated. The dielectric constant ϵ′, dielectric loss ϵ″ and AC conductivity σAC were also found to increase on heating up to 100 °C. The results indicate that ϵ′, ϵ″ and σAC depend not only on the frequency and temperature but also on the laser fluence.

Characterization of a β-xylosidase produced by a mutant derivative of Humicola lanuginosa in solid state fermentation

The production of extracellular β-xylosidase by a newly isolated mutant derivative of Humicola lanuginosa M7D on lignocellulosic substrates and xylan was maximized in solid state fermentation by adopting a search technique varying one parameter at a time. The H. lanuginosa mutant achieved maximum production of β-xylosidase (728 IU g−1 substrate, YP/S) when grown on Vogel’s medium containing xylan, followed by medium containing corncobs (669 IU g−1) supplemented with corn steep liquor (initial pH 6.5, moisture level 75%) at 45°C. Purified mutant- and parent-derived enzyme exhibited Km values of 1.8 and 2.0 mM, respectively. Both enzymes were optimally active at pH 8.5 and a temperature of 60°C. Both enzymes displayed high thermostability, with a half-life of 2.9 and 0.9 min, enthalpy of denaturation (ΔH*) of 102.1 and 110.10 kJ mol−1, entropy of denaturation (ΔS*) of −38.5 and −4.5 J/mol K, and free energy of denaturation (ΔG*) of 115.7 and 111.7 kJ/mol at 80°C for the mutant- and parent organism-derived enzymes, respectively. The kinetic and thermodynamic properties suggest that the β-xylosidases from both strains are superior to several previously reported enzymes from other thermophilic species, and may have potential applications in various industrial fields.

Dynamic light scattering and atomic force microscopy techniques for size determination of polyurethane nanoparticles

Nanoparticles have applications in various industrial fields principally in drug delivery. Nowadays, there are several processes for manufacturing colloidal polymeric systems and methods of preparation as well as of characterization. In this work, Dynamic Light Scattering and Atomic Force Microscopy techniques were used to characterize polyurethane nanoparticles. The nanoparticles were prepared by miniemulsion technique. The lipophilic monomers, isophorone diisocyanate (IPDI) and natural triol, were emulsified in water containing surfactant. In some formulations the poly(ethylene glycol) was used as co-monomer to obtain the hydrophilic and pegylated nanoparticles. Polyurethane nanoparticles observed by atomic force microscopy (AFM) were spherical with diameter around 209 nm for nanoparticles prepared without PEG. From AFM imaging two populations of nanoparticles were observed in the formulation prepared with PEG (218 and 127 nm) while dynamic light scattering (DLS) measurements showed a monodisperse size distribution around 250 nm of diameters for both formulations. The polydispersity index of the formulations and the experimental procedures could influence the particle size determination with these techniques.

Mechanism of cytotoxic action of perfluorinated acids.: I. Alteration in plasma membrane potential and intracellular pH level

Perfluorinated (aliphatic) acids (PFAs) and congeners have many applications in various industrial fields and household for decades. Years later they have been detected in wildlife and this has spurred interest in environmental occurrence as well as influencing living organisms. PFAs were established as peroxisome proliferators and hepatocarcinogens. Amphipatic structure suggests that they may alter cell membrane potential (mbΔΨ) and/or induce changes in cytosolic pH (pHi). The aim of this study was to examine the correlation between changes of above parameters and PFAs structure (CF 6–CF 12) in human colon carcinoma HCT116 cells. mbΔΨ and pHi were measured by flow cytometry using fluorescence polarization of the plasma membrane probe 3,3′-dipentyloxacarbocyanine (DiOC 5(3)) and fluorescein diacetate (FDA), respectively. Dose- and time-dependent manner analysis revealed relatively fast depolarization of plasma membrane and acidification of cytosol both positively correlated with fluorocarbon chain length. mbΔΨ depletion after 4 h of incubation reached 8.01% and 30.08% for 50 μM PFOA and 50 μM PFDoDA, respectively. Prolonged treatment (72 h) led to dramatic dissipation of membrane potential up to 21.65% and 51.29% and strong acidification to pHi level at 6.92 and 6.03 at the presence of above compounds, respectively. The data demonstrate that PFAs can alter plasma membrane protonotrophy with the mode dependent on the compound hydrophobicity.

Nanofriction of diamond coatings obtained by flame process

With its noteworthy physical and chemical properties, diamond is expected to find many applications in various industrial fields, particularly with the expansion of the new nanotechnologies. In order to optimise their use in these specific conditions, it is essential to better understand the very complex tribological behaviour of diamond coatings. This latest is studied from a macroscopic point of view, but essential facts which occur at a nanoscopic scale are still not well known. The mechanisms involved not only in the nucleation and growth of the diamond crystals, but also in the nanofriction of the coatings, must be understood. One way to reach this purpose is to analyse the crystals morphology and behaviour at a very small scale : atomic force microscopy (AFM) seems to be a suitable technique for this work.The crystals morphology is initially studied in tapping mode; the first observations indicated that secondary growth happened on the facets. Experiments in contact mode are then carried out : the observed behaviours are different on a facet, on a crystal, or on a part of the coating. The load applied to the tip seems to have an influence too as the friction force increases when the contact load becomes higher; moreover, these variations are clearly linked to the topography of the scanned surfaces. The purpose of this nano-experimental work is to get information to better understand the friction properties of the diamond coatings at a nanoscopic scale, and to establish, if possible, a potential correlation between the behaviour noticed at the macroscopic scale, and the one obtained with AFM measurements.

Characterization of a Novel Glucoamylase from the Thermoacidophilic Archaeon Picrophilus torridus Heterologously Expressed in E. coli

AbstractThere is an interest in the production of heat‐ and acid‐stable enzymes due to their potential application in various industrial fields, particularly in the food, brewery, and textile industries. Microorganisms living in extreme habitats are a good source for such enzymes as they enable to perform biotransformation reactions under non‐conventional conditions. After the complete genome analysis of the thermoacidophilic archaeon Picrophilus torridus (optimal growth at pH 0.7 and 60 °C) a number of genes were identified that encode for amylolytic enzymes, proteases, and esterases. A gene encoding an intracellular glucoamylase from P. torridus was cloned and successfully expressed in E. coli. The recombinant enzyme was purified to homogeneity with a yield of 37 % by heat treatment, anion exchange, and gel filtration chromatography. As revealed by non‐denaturating PAGE, the active enzyme forms a homotetramer (73 kDa/subunit). The recombinant glucoamylase shows activity between 30 °C and 65 °C and a pH of between 4.5 and 6.5. Interestingly, the enzyme shows unique substrate specificity compared to already known glucoamylases. In addition to the hydrolysis of branched and linear α‐glucans, the purified enzyme preferentially attacks maltotriose. The Vmax for maltotriose (10 U/mg) is even higher than the Vmax for starch (8 U/mg). The high maltotriose preference of this archaeal enzyme is unique among all glucoamylases described so far.

A monoclonal antibody to cyclomaltoheptaose (beta-cyclodextrin): Characterization and use for immunoassay of beta-cyclodextrin and its derivatives.

Cyclomaltoheptaose (beta-cyclodextrin, beta-CD) is a promising compound for application in various industrial fields because of its ability to entrap various compounds into its hydrophobic cavity. A monoclonal antibody (A7) to beta-CD was generated by using a conjugate of glucosaminylmaltosyl-beta-CD and bovine serum albumin as an antigen. The A7 monoclonal antibody was IgM/kappa and reacted with beta-CD with high specificity. The epitope recognized by the A7 monoclonal antibody seemed to be located on the secondary hydroxyl groups of the rim side of the beta-CD molecule. The dissociation constant of the complex of beta-CD and the immobilized A7 monoclonal antibody was determined to be 1.2 x 10(-4) M. A competitive ELISA using the A7 monoclonal antibody enabled determination of beta-CD and its derivatives with a detection limit of 0.05 muM. This immunoassay was useful to determine beta-CD in biological fluids such as human plasma and urine after appropriate pretreatment of the samples.

Some characteristics of polyoxyethylene sorbitol tetra‐oleate: Oligomer type emulsifier

AbstractPolyoxyethylene (P) sorbitol tetra‐oleates with molecular weights of 2000 to 4000 were synthesized. They may be regarded as tetramers of those ordinary surfactants that consist of one hydrophilic and one hydrophobic group. Some emulsifying properties of the tetrameric surfactants were investigated including the phase inversion temperature (PIT, HLB‐temperature). These surfactants are effective at relatively low concentration, they are stable for coalescence, and they are less irritating than conventional surfactants. Specifically, they proved to be good emulsifiers for unsaturated triglycerides such as olive oil. The mean droplet diameter of the emulsion was small, 1.5 microns. The emulsifying activity of these oligomer type surfactants for olive oil was improved markedly by the addition of 0.2–0.9 wt % of sodium oleate. Such effective performances of these surfactants have not been recognized in ordinary surfactants. It is expected that these oligomer type surfactants may find applications in various industrial fields.