2,907 research outputs found

    Corrosion Prevention of Carbon Steel Using Tapioca Polysaccharides – Based Coating

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    Coating is widely used as corrosion prevention and also for aesthetic property. The composition of common industry coating consists of binder, pigment extender, solvent and additive. This coating composition is detrimental to the environment because it contains Volatile Organic Compound (VOC). Besides that, the synthetic polymers are neither renewable nor biodegradable which impact the sustainability of the nature. With an intention to provide alternative solution for global coating issues and highlight the application of green technology, the effectiveness of tapioca polysaccharides(TPS) based coating for corrosion prevention of carbon steel is evaluated. The basic performance can be determined by conducting standard coating testing with salt spray testing as per ASTM B117 and adhesion testing as per ASTM D3359. With 85% epoxy- 15% TPS biopolymer mixture, the coating showed satisfactory anti corrosive behaviour in protecting the carbon steel. The adhesion strength of the mixture was also passed the average pressure acceptance criteria used in industry. With the promising preliminary results, the potential of the epoxy-TPS biopolymer coating to contribute to green technology is positive. However, more tests should be conducted to characterize the formulatio

    Astringent Food Compounds and Their Interactions with Taste Properties

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    Astringency is traditionally thought to be induced by plant tannins in foods. Because of this current research concerning the mechanism of astringency is focused on tannin‐protein interactions and thus on precipitation, which may be perceived by mechanoreceptors. However, astringency is elicited by a wide range of different phenolic compounds, as well as, some non‐phenolic compounds in various foods. Many ellagitannins or smaller compounds that contribute to astringent properties do not interact with salivary proteins and may be directly perceived through some receptors. Generally, the higher degree of polymerization of proanthocyanidins can be associated with more intense astringency. However, the astringent properties of smaller phenolic compounds may not be directly predicted from the structure of a compound, although glycosylation has a significant role. The astringency of organic acids may be directly linked to the perception of sourness, and this increases along with decreasing pH. Astringency can be divided into different sub‐qualities, including even other qualities than traditional mouth‐drying, puckering or roughing sensations. Astringency is often accompanied by bitter or sour or both taste properties. The different sub‐qualities can be influenced by different astringent compounds. In general, the glycolysation of the phenolic compound results in more velvety and smooth mouthdrying astringency. Flavonol glycosides and other flavonoid compounds and ellagitannins contribute to this velvety mouthdrying astringency. Additionally, they often lack the bitter properties. Proanthocyanidins and phenolic acids elicit more puckering and roughing astringency with some additional bitter properties. Quercetin 3‐O‐rutinoside, along with other quercetin glycosides, is among the key astringent compounds in black tea and red currants. In foods, there are always various other additional attributes that are perceived at the same with astringency. Astringent compounds themselves may have other sensory characteristics, such as bitter or sour properties, or they may enhance or suppress other sensory properties. Components contributing to these other properties, such as sugars, may also have similar effects on astringent sensations. Food components eliciting sweetness or fattiness or some polymeric polysaccharides can be used to mask astringent subqualities. Astringency can generally be referred to as a negative contributor to the liking of various foods. On the other hand, perceptions of astringent properties can vary among individuals. Many genetic factors that influence perceptions of taste properties, such as variations in perceiving a bitter taste or variations in saliva, may also effect the perception of astringency. Individuals who are more sensitive to different sensations may notice the differences between astringent properties more clearly. This may not have effects on the overall perception of astringency. However, in many cases, the liking of astringent foods may need to be learned by repetitive exposure. Astringency is often among the key sensory properties forming the unique overall flavour of certain foods, and therefore it also influences whether or not a food is liked. In many cases, astringency may be an important sub‐property suppressed by other more abundant sensory properties, but it may still have a significant contribution to the overall flavour and thus consumer preferences. The results of the practical work of this thesis show that the astringent phenolic compounds are mostly located in the skin fractions of black currants, crowberries and bilberries (publications I–III). The skin fractions themselves are rather tasteless. However, the astringent phenolic compounds can be efficiently removed from these skin fractions by consecutive ethanol extractions. Berries contain a wide range of different flavonol glycosides, hydroxycinnamic acid derivatives and anthocyanins and some of them strongly contribute to the different astringent and bitterness properties. Sweetness and sourness are located in the juice fractions along with the majority of sugars and fruit acids. The sweet and sour properties of the juice may be used to mask the astringent and bitterness properties of the extracts. Enzymatic treatments increase the astringent properties and fermented flavour of the black currant juice and decrease sweetness and freshness due to the effects on chemical compositions (IV). Sourness and sweetness are positive contributors to the liking of crowberry and bilberry fractions, whereas bitterness is more negative (V). Some astringent properties in berries are clearly negative factors, whereas some may be more positive. The liking of berries is strongly influenced by various consumer background factors, such as motives and health concerns. The liking of berries and berry fractions may also be affected by genetic factors, such as variations in the gene hTAS2R38, which codes bitter taste receptors (V).Siirretty Doriast

    Use of high-dimensional spectral data to evaluate organic matter, reflectance relationships in soils

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    Recent breakthroughs in remote sensing technology have led to the development of a spaceborne high spectral resolution imaging sensor, HIRIS, to be launched in the mid-1990s for observation of earth surface features. The effects of organic carbon content on soil reflectance over the spectral range of HIRIS, and to examine the contributions of humic and fulvic acid fractions to soil reflectance was evaluated. Organic matter from four Indiana agricultural soils was extracted, fractionated, and purified, and six individual components of each soil were isolated and prepared for spectral analysis. The four soils, ranging in organic carbon content from 0.99 percent, represented various combinations of genetic parameters such as parent material, age, drainage, and native vegetation. An experimental procedure was developed to measure reflectance of very small soil and organic component samples in the laboratory, simulating the spectral coverage and resolution of the HIRIS sensor. Reflectance in 210 narrow (10 nm) bands was measured using the CARY 17D spectrophotometer over the 400 to 2500 nm wavelength range. Reflectance data were analyzed statistically to determine the regions of the reflective spectrum which provided useful information about soil organic matter content and composition. Wavebands providing significant information about soil organic carbon content were located in all three major regions of the reflective spectrum: visible, near infrared, and middle infrared. The purified humic acid fractions of the four soils were separable in six bands in the 1600 to 2400 nm range, suggesting that longwave middle infrared reflectance may be useful as a non-destructive laboratory technique for humic acid characterization

    Selluloosan talteenotto viherlevistÀ tekstiilien valmistamista varten

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    This thesis investigated if the cellulose from algal species Cladophora glomerata could be used as a feedstock for manufacturing textile fibers using the Ioncell-F process in a sustainable way. To achieve sustainability, it was investigated if the current methods for isolating algal cellulose could be replaced with more environmentally benign processes. The current literature available on the biorefining and fractionation of algal biomass was reviewed, and it was concluded that a major issue in the field is that most of the studies cannot readily be compared with each other, making it difficult to review and compare different fractionation options. To address this issue this thesis suggests that existing knowledge on the biological categorization of algae could be used as a basis for producing more systematic information on algal fractionation. The fractionation of the green algae, Cladophora glomerata, biomass was investigated by a two-stage fractionation process, and the composition of the original feedstock and the fractionation products were characterized in detail. Three different fractionation schemes were tested: 1) autohydrolysis + low-concentration alkali treatment 2) low-concentration acid treatment + low-concentration alkali treatment 3) acid treatment + alkali treatment. It was found that these treatments were not as effective as existing methods in isolating algal cellulose as the literature methods. Ultimate cellulose purity of 63 % was achieved using the methods tested in this thesis. The cellulose produced by the fractionation study was subjected to an acid degradation to decrease its degree of polymerization (DP) to make it more suitable for textile production. It was observed to be much more resistant towards acid degradation than terrestrial celluloses, and to have leveling-off degree of polymerization of 940, which is approximately 3 times higher than that of terrestrial cellulose sources. A small amount of textile fibers was produced from this DP-adjusted material and their properties were compared with Ioncell-F fibers made from more conventional feedstocks. The produced algal fibers were observed to have slightly worse technical properties than the more conventional prehydrolysis kraft pulp-based fibers. This thesis demonstrated the first ever production of cellulosic textile fibers made purely out of algal raw material. This result was achieved with relatively impure cellulose and it is clear that there is still much that can be done for improving this process. However, as a proof-of-concept demonstration, this thesis implies that green algae, a highly abundant and an under-utilized natural resource, can be used as a raw material for high-value cellulosic products.TĂ€mĂ€ diplomityö tutki voitaisiinko Cladophora glomerata – viherlevĂ€n selluloosasta valmistaa tekstiilikuituja kĂ€yttĂ€mĂ€llĂ€ Ioncell-F teknologiaa. LisĂ€ksi diplomityössĂ€ pyrittiin korvaamaan nykyisiĂ€ levĂ€selluloosan talteenottometodeja ympĂ€ristöystĂ€vĂ€llisemmillĂ€ prosesseilla. TyössĂ€ arvioitiin levĂ€biomassan biojalostamiseen ja fraktiointiin liittyvĂ€n tieteellisen kirjallisuuden nykytilaa ja todettiin ettĂ€ kyseisen alan keskeisenĂ€ ongelmana on, ettei suurin osa tehdystĂ€ tutkimuksesta ole vertailukelpoista muiden alan tutkimusten kanssa. Ratkaisuna tĂ€hĂ€n ongelmaan tĂ€mĂ€ työ ehdottaa, ettĂ€ olemassa olevaa tietoa levien biologisesta luokittelusta voitaisiin kĂ€yttÀÀ pohjana levien fraktiointiin liittyvĂ€n tiedon uudelleenjĂ€rjestĂ€miseen systemaattisemmaksi kokonaisuudeksi. Cladophora glomerata – viherlevĂ€n fraktiontia tutkittiin kĂ€yttĂ€mĂ€llĂ€ kaksivaiheista fraktiontiprosessia. SekĂ€ LevĂ€biomassan alkuperĂ€inen, ettĂ€ fraktionaatiotuotteiden kemiallinen koostumus selvitettiin yksityiskohtaisesti. TyössĂ€ testattiin kolmea erilaista fraktionaatioskeemaa: 1) Autohydrolyysi + Keitto laimeassa emĂ€ksessĂ€ 2) Keitto laimeassa hapossa + Keitto laimeassa emĂ€ksessĂ€ 3) Keitto hapossa + Keitto emĂ€ksessĂ€. TyössĂ€ todettiin etteivĂ€t nĂ€mĂ€ kĂ€sittelyt olleet yhtĂ€ tehokkaita kuin olemassaolevat kirjallisuudessa esitetyt metodit levĂ€selluloosan talteenottamiseksi. Työn fraktiontimetodeilla tuotettua selluloosaa kĂ€siteltiin edelleen, jotta se soveltuisi paremmin tekstiilituotantoon Ioncell-F menetelmĂ€llĂ€. LevĂ€selluloosan polymerisaatioastetta pienennettiin happohydrolyysillĂ€, mutta sen huomattiin olevan huomattavasti vastustuskykyisempi happohydrolyysiĂ€ vastaan kuin maa-kasveista perĂ€isin oleva selluloosa. LisĂ€ksi levĂ€selluloosan polymerisaatioasteen tasaantuminen tapahtui 940 yksikön polymerisaatioasteessa, mikĂ€ on noin 3 kertaa korkeampi arvo kuin maa-kasveista perĂ€isin olevalla selluloosalla. TyössĂ€ tuotettiin pieni mÀÀrĂ€ tekstiilikuituja tĂ€stĂ€ polymerisaatio-aste sÀÀdetystĂ€ materiaalista, ja tuotettujen tekstiilikuitujen ominaisuuksia verrattiin liukosellusta valmistettuihin Ioncell-F kuituihin. Tuotettujen levĂ€tekstiili-kuitujen tekniset ominaisuudet olivat hieman heikompia kuin konventionaalisten liukosellusta valmistettujen Ioncell-F kuitujen. TĂ€ssĂ€ diplomityössĂ€ valmistettiin ensimmĂ€istĂ€ kertaa koskaan selluloosapohjaisia tekstiilikuituja puhtaasti levĂ€pohjaisesta raaka-aineesta. NĂ€mĂ€ kuidut kyettiin valmistamaan verrattain epĂ€puhtaasta selluloosasta, ja on selvÀÀ, ettĂ€ valmistustekniikkaa kyettĂ€isiin vielĂ€ kehittĂ€mÀÀn. TĂ€mĂ€ työ kuitenkin kykeni osoittamaan demonstraatioluonteisesti, ettĂ€ viherlevĂ€t, jotka ovat erittĂ€in yleinen, mutta alikĂ€ytetty luonnonvara, soveltuvat arvokkaiden selluloosatuotteiden raaka-aineeksi

    Optimization of the production of bioethanol from duckweed (Lemna minor)

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    This project has investigated the production of bioethanol from duckweed (Lemna minor) biomass. The project includes four main sections: firstly, analysis of the chemical characteristics of duckweed, particularly the polysaccharides of the cell wall; secondly, exploration of suitable commercial enzymes for degrading duckweed biomass to fermentable sugars; thirdly, optimisation of pretreatments and enzymatic saccharification; finally, fermentation and optimisation of the ethanol yield. Pond-grown L. minor contained 51.2 % carbohydrate (w/w dry matter) of which 77 % (including glucose, galactose and xylose) is fermentable. A series of enzymatic hydrolyses was used to evaluate the commercial enzymes and optimise conditions for their use in the saccharification of duckweed biomass. Celluclast 1.5L (CE) and Novozyme 188 (BG) were identified as suitable for hydrolysing duckweed cell walls (prepared as alcohol insoluble residues). The additional use of thermophysical pretreatment (steam explosion) results in a dramatic decrease in the amount of enzyme required for quantitative saccharification. A more advanced commercial cellulase cocktail (CellicÂź CTec 2; CTec 2) is likely to further reduce the enzyme cost. Methods for the simultaneous saccharification, using CTec 2 and BG, and fermentation of steam exploded duckweed were developed. These resulted in an 80 % ethanol yield at a diluted substrate concentration (1 % w/v). However the ethanol yield decreased dramatically at higher substrate concentrations (to 18 % at 20 % w/v substrate concentration, which is a highly viscous suspension). Further studies involved the development of approaches to address this: (i) increasing the yeast titre in the inoculum or (ii) growing the inoculum on steam-exploded duckweed. These approaches facilitated an ethanol yield of up to 70 % (w/w) at a substrate concentration of 20 % (w/v). Maximising the final ethanol yield is of great importance in reducing the costs of production. The optimized ethanol production process indicates the technical potential for industrial ethanol production from duckweed. Operating costs have also been estimated and are discussed in relation to the potential exploitation of protein as a co-product

    Separation and Extraction of Proteins and Polysaccharides from the Seaweed Palmaria Palmata using Enzyme Digestion

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    Vetenskapliga artiklar föreslÄr att xylan Àr delvis bundet till proteinerna i dulse. Detta kan leda till minskad tillgÀnglighet av proteinerna och leda till svÄrigheter att smÀlta dessa i tarmen. Denna rapport har för avsikt att hitta och optimera metoder för extraktion av proteiner och metoder för att separera de proteiner och polysackarider som förekommer i dulse. Metoderna som anvÀnds Àr hydrolys med proteaser och hydrolys av xylan med xylanase. De analytiska metoderna som anvÀnds för att utvÀrdera nÀringsinnehÄllet i proverna Àr SDS-PAGE, Bradfordmetoden, fenolsvavelsyrametoden, TLC och HPEAC-PAD. Hydrolys med proteaser hade begrÀnsad framgÄng, endast en liten ökning i proteininnehÄllet i provet erhölls (totalt 46.6%) nÀr hydrolys med Umamizyme utfördes. Hydrolys med xylanase visade sig ha bÀst potential med en proteinkoncentration pÄ 53.4% i provet. Vidare optimering av denna metod, kan bidra med vÀrdefull kunskap inom mat- och foderindustrin.Seaweed has a great potential within human food and animal feed industry. Palmaria palmata (P. palmata) or more commonly dulse, is a type of red seaweed which has a high protein content (8-35%), rich in minerals such as iodine and iron and contain high levels of dietary fibers. The main polysaccharide in dulse is xylan. It has been suggested that the xylans are linked to the proteins in the seaweed. This may decrease the accessibility and the digestion of the proteins present in dulse. This paper intends to find and optimize methods for extraction of the proteins and separation of the proteins and polysaccharides in dulse. The methods used to treat dulse, includes protease hydrolysis, hydrolyse of xylan with xylanase. The analytical methods to analyze the nutritional content includes SDS-PAGE, Bradford assay, phenol-sulfuric acid method, TLC and HPEAC-PAD. Hydrolysis with proteases showed limited success, only a small increase in protein content (total 46.6%) was found when hydrolysing with Umamizyme. Hydrolysis with xylanase showed greater success with a protein concentration of 53.4%. Hydrolyse with xylanase showed best potential when separating polysaccharides from proteins and extracting proteins in dulse. Further optimization of this method could generate valuable knowledge which can be utilized within human food and animal feed industries

    Extraction of plant biopolymers and their use in gas sensitive hybrid materials

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    Biopolymers have spurred interest because of their outstanding properties, such as waterproofing, antimicrobial activity and resistance, as well as the ability to help form hybrid materials with stimuli-responsive properties. With this purpose, extractions of suberin from cork (Quercus suber) and white potato skin (Solanum tuberosum L. cv. Monalisa), and cutin from tomato skin (Solanum lycopersicum) have been achieved through a novel process based on cholinium hexanoate’s selective cleavage of acylglycerol ester bonds, allowing the partially intact recovery of the biopolymers mentioned. The extraction of suberin from cork resulted in yields ranging from ≈2-20%, using extraction periods of 30 minutes, 1 hour and 2 hours, while 2-hour extraction from white potato peels yielded ≈4% suberin and 2-hour extraction from both natural and enzymatically digested tomato skin yielded ≈6% and ≈1% cutin, respectively. The application of the extracted biopolymers as sensing materials for an electronic nose (E-Nose) under development was tested by combining the biopolymers suberin and cutin with water and the liquid crystal 2-cyano-4-pentylbiphenyl (5CB). The hybrid materials obtained were processed as thin films and further exposed to five volatile organic compounds (VOCs) with different polarities – hexane, toluene, dichloromethane, ethanol and acetone. An optical response was recorded upon VOC exposure and the results revealed a tendency from suberin-based films to higher optical responses to toluene, dichloromethane and acetone and maintenance of their yield and morphology after exposure, while cutin-based films disintegrated after exposure to toluene and revealed much lower optical responses to all VOCs. No film gave an optical signal in the presence of ethanol or hexane in the E-Nose. These findings strengthen the interest in exploiting plant biopolymers, specifically the polyester suberin, as valuable components for the production of hybrid materials with stimuli responsive properties

    Supramolecular Biopolymeric Composite Materials: Green Synthesis, Characterization and Applications

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    Macrocycles, such as crown ethers (CRs) and resorcinarenes (RESs), exhibit selective complexation of heavy metal ions and organic pollutants respectively. Consequently, they have been investigated for their suitability in adsorbing these aqueous pollutants. However, they are difficult to handle and recycle for reuse because, by themselves, they can only be fabricated in powder form. To alleviate this challenge, we developed a method to encapsulate these macrocycles into film-forming polysaccharides--cellulose (CEL) and chitosan (CS). This was achieved by using a green and recyclable solvent, an ionic liquid, to dissolve both macrocycles and polysaccharides and regenerate corresponding composites in water. Resultant composites were characterized by FTIR, UV-Visible, X-ray powder diffraction and scanning electron microscopy. These polysaccharides are attractive because they are naturally abundant, biodegradable and biocompatible. The composites retained desirable properties of their individual constituents, namely superior mechanical strength (from CEL), excellent adsorption capability for cadmium and zinc ions (from CRs and CS) and organic solutes (from RESs and CS). Specifically, increasing the concentration of CEL from 50% to 90% in [CEL+CR] resulted in almost 2X increase in tensile strength. Adding 40% benzo 15-crown-5 ether (B15C5) to CS led to a 4X enhancement in the amount of cadmium ions adsorbed by [CS+B15C5]. Interestingly, RES-based composites exhibited selectivity amongst dinitrobenzene (DNB) isomers. For example, one g of [CEL+RES] adsorbed more 1,2-DNB (5.37±0.05 mol L-1) than 1,3-DNB (4.52±0.03 mol L-1) and 1,4-DNB (2.74±0.04 mol L-1). These results help to extend the potential applications of supramolecular composites in water remediation. We also successfully synthesized hydroxyapatite (HAp) in situ by alternately soaking [CEL+CS] composite films in calcium and phosphate salt solutions. These composites will be expected to be osteoconductive (due to HAp), thereby necessitating their use in bone tissue engineering. In another related study, we developed a simple, one step process to encapsulate an antibiotic, ciprofloxacin (CPX) in composites containing various proportional concentrations of CEL, CS, and keratin (KER). KER was found to slow down the release of CPX from the composites. These results clearly indicate that the release of CPX can be controlled by judicious adjustment of the concentrations of KER in the composites

    Corrosion Prevention of Carbon Steel Using Tapioca Polysaccharides – Based Coating

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    Coating is widely used as corrosion prevention and also for aesthetic property. The composition of common industry coating consists of binder, pigment extender, solvent and additive. This coating composition is detrimental to the environment because it contains Volatile Organic Compound (VOC). Besides that, the synthetic polymers are neither renewable nor biodegradable which impact the sustainability of the nature. With an intention to provide alternative solution for global coating issues and highlight the application of green technology, the effectiveness of tapioca polysaccharides(TPS) based coating for corrosion prevention of carbon steel is evaluated. The basic performance can be determined by conducting standard coating testing with salt spray testing as per ASTM B117 and adhesion testing as per ASTM D3359. With 85% epoxy- 15% TPS biopolymer mixture, the coating showed satisfactory anti corrosive behaviour in protecting the carbon steel. The adhesion strength of the mixture was also passed the average pressure acceptance criteria used in industry. With the promising preliminary results, the potential of the epoxy-TPS biopolymer coating to contribute to green technology is positive. However, more tests should be conducted to characterize the formulatio

    SciTech News Volume 71, No. 1 (2017)

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    Columns and Reports From the Editor 3 Division News Science-Technology Division 5 Chemistry Division 8 Engineering Division Aerospace Section of the Engineering Division 9 Architecture, Building Engineering, Construction and Design Section of the Engineering Division 11 Reviews Sci-Tech Book News Reviews 12 Advertisements IEEE
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