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Sample records for brazilian silica rice

  1. Silica Derived from Burned Rice Hulls

    Directory of Open Access Journals (Sweden)

    M.F. de Souza

    2002-10-01

    Full Text Available Three new processes to obtain silica having high specific surface area from burned pre-treated rice hulls are presented and discussed. These procedures allow for the simultaneous recovery of biomass energy and the production of high quality silica at thermoelectric plants, without the risk of using corrosive substances in the burning process. The first method involves treatment of the hull with hot organic acid solutions before burning, the second with boiling water, both using an autoclave at temperatures close to150 °C, while the third method renders the hull fragile by treating it at 250 °C and reducing it to a fine powder before burning. The first two methods result in white amorphous silica that can show 500 m²/g of specific surface area. The third method, which does not remove the alkaline elements from the hull, produces an amorphous gray carbon-free powder whose specific surface area can be as high as 250 m²/g. An investigation of the specific surface area of the prepared silica indicates the alkaline elements are not mixed with silica in the hulls or combined as insoluble compounds. A comparison is made of these processes and the dissolution of silica by sodium hydroxide solutions is discussed.

  2. Preparation of High Grade Silica from Rice Husk for Zeolite ...

    African Journals Online (AJOL)

    ABSTRACT: Silica powder with approximately 96% purity was extracted from rice husk (RH) and used as a silica source for the synthesis of zeolite Y ... produced commercially, the ones produced from plant origins such as rice husks have ... About 1.7g sodium hydroxide pellets were dissolved in. 7.5ml deionized water and ...

  3. Genetic base of Brazilian irrigated rice cultivars

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    Hudson de Oliveira Rabelo

    2015-08-01

    Full Text Available The aim of this study was to estimate the genetic base of Brazilian irrigated rice cultivars released in the period from 1965 to 2012. The genealogies of the cultivars were obtained based on information from marketing folders, websites, crossings records, and scientific articles. The following factors were calculated: relative genetic contribution (RGC, accumulated genetic contribution (AGC, frequency (in percentage of each ancestor in the genealogy (FAG, number of ancestors that constitute each cultivar (NAC,number of ancestors responsible for 60%, 70%, 80% and 90% of the genetic base (NAGB, and average number of ancestor per cultivar (ANAC. The cultivars were also grouped based on the period of release (1965-1980, 1981-1990, 1991-2000 and 2001-2012. For each grouping, the previously described factors were also estimated. A total of 110 cultivars were studied and it was concluded that the genetic base of Brazilian irrigated rice cultivars is narrow.

  4. Soil Incorporation of Silica-Rich Rice Husk Decreases Inorganic Arsenic in Rice Grain.

    Science.gov (United States)

    Seyfferth, Angelia L; Morris, Andrew H; Gill, Rattandeep; Kearns, Kelli A; Mann, Jessica N; Paukett, Michelle; Leskanic, Corey

    2016-05-18

    Arsenic decreases rice yield, and inorganic grain As threatens human health; thus, strategies to decrease rice As are critically needed. Increased plant-available silica (Si) can decrease rice As, yet the source of Si matters. Rice husk, an underutilized and Si-rich byproduct of rice production that contains less labile C and an order of magnitude less As than rice straw, may be an economically viable Si resource to decrease rice As, yet the impact of rice husk incorporation on As in the rice-soil nexus has not been reported. This proof-of-concept study shows that rice husk incorporation to soil (1% w/w) decreases inorganic grain As by 25-50% without negatively affecting grain Cd, yield, or dissolved CH4 levels. Rice husk is a critical yet perhaps overlooked resource to improve soil quality through enhanced nutrient availability and attenuate human health risks through consumption of As-laden grain.

  5. Microbial Activity and Silica Degradation in Rice Straw

    Science.gov (United States)

    Kim, Esther Jin-kyung

    Abundantly available agricultural residues like rice straw have the potential to be feedstocks for bioethanol production. Developing optimized conditions for rice straw deconstruction is a key step toward utilizing the biomass to its full potential. One challenge associated with conversion of rice straw to bioenergy is its high silica content as high silica erodes machinery. Another obstacle is the availability of enzymes that hydrolyze polymers in rice straw under industrially relevant conditions. Microbial communities that colonize compost may be a source of enzymes for bioconversion of lignocellulose to products because composting systems operate under thermophilic and high solids conditions that have been shown to be commercially relevant. Compost microbial communities enriched on rice straw could provide insight into a more targeted source of enzymes for the breakdown of rice straw polysaccharides and silica. Because rice straw is low in nitrogen it is important to understand the impact of nitrogen concentrations on the production of enzyme activity by the microbial community. This study aims to address this issue by developing a method to measure microbial silica-degrading activity and measure the effect of nitrogen amendment to rice straw on microbial activity and extracted enzyme activity during a high-solids, thermophilic incubation. An assay was developed to measure silica-degrading enzyme or silicase activity. This process included identifying methods of enzyme extraction from rice straw, identifying a model substrate for the assay, and optimizing measurement techniques. Rice straw incubations were conducted with five different levels of nitrogen added to the biomass. Microbial activity was measured by respiration and enzyme activity. A microbial community analysis was performed to understand the shift in community structure with different treatments. With increased levels of nitrogen, respiration and cellulose and hemicellulose degrading activity

  6. Characterisation of silica derived from rice husk (Muar, Johor, Malaysia) decomposition at different temperatures

    Science.gov (United States)

    Azmi, M. A.; Ismail, N. A. A.; Rizamarhaiza, M.; W. M. Hasif. A. A., K.; Taib, H.

    2016-07-01

    Rice husk was thermally decomposed to yield powder composed of silica (SiO2). Temperatures of 700°C and 1000°C were chosen as the decomposition temperatures. X-Ray Diffraction (XRD), X-Ray Florescence (XRF), Fourier Transform Infrared (FTIR), and Field Emission Scanning Electron Microscope (FESEM) analyses were conducted on a synthetic silica powder (SS-SiO2) and the rice husk ash as for the comparative characterisation study. XRD analyses clearly indicated that the decomposed rice husk yielded silica of different nature which are Crystalline Rice Husk Silica (C-RHSiO2) and Amorphous Rice Husk Silica (A-RHSiO2). Moreover, it was found that SS-SiO2 was of Quartz phase, C-RHSiO2 was of Trydimite and Cristobalite. Through XRF detection, the highest SiO2 purity was detected in SS-SiO2 followed by C-RHSiO2 and A-RHSiO2 with purity percentages of 99.60%, 82.30% and 86.30% respectively. FTIR results clearly indicated silica (SiO2) bonding 1056, 1064, 1047, 777, 790 and 798 cm-1) increased as the crystallinity silica increased. The Cristobalite phase was detected in C-RH SiO2 at the wavelength of 620 cm-1. Morphological features as observed by FESEM analyses confirmed that, SS-SiO2 and C-RH SiO2 showed prominent coarse granular morphology.

  7. Synthesis, characterization and catalytic activity of carbon-silica hybrid catalyst from rice straw

    Science.gov (United States)

    Janaun, J.; Safie, N. N.; Siambun, N. J.

    2016-07-01

    The hybrid-carbon catalyst has been studied because of its promising potential to have high porosity and surface area to be used in biodiesel production. Silica has been used as the support to produce hybrid carbon catalyst due to its mesoporous structure and high surface area properties. The chemical synthesis of silica-carbon hybrid is expensive and involves more complicated preparation steps. The presence of natural silica in rice plants especially rice husk has received much attention in research because of the potential as a source for solid acid catalyst synthesis. But study on rice straw, which is available abundantly as agricultural waste is limited. In this study, rice straw undergone pyrolysis and functionalized using fuming sulphuric acid to anchor -SO3H groups. The presence of silica and the physiochemical properties of the catalyst produced were studied before and after sulphonation. The catalytic activity of hybrid carbon silica acid catalyst, (H-CSAC) in esterification of oleic acid with methanol was also studied. The results showed the presence of silica-carbon which had amorphous structure and highly porous. The carbon surface consisted of higher silica composition, had lower S element detected as compared to the surface that had high carbon content but lower silica composition. This was likely due to the fact that Si element which was bonded to oxygen was highly stable and unlikely to break the bond and react with -SO3H ions. H-CSAC conversions were 23.04 %, 35.52 % and 34.2 7% at 333.15 K, 343.15 K and 353.15 K, respectively. From this research, rice straw can be used as carbon precursor to produce hybrid carbon-silica catalyst and has shown catalytic activity in biodiesel production. Rate equation obtained is also presented.

  8. Influence of roasting-quenching pretreatment on the rice husk silica prepared by calcination method

    Science.gov (United States)

    Maksum, Ahmad; Rustandi, Andi; Permana, Sulaksana; Soedarsono, Johny Wahyuadi

    2017-03-01

    Calcination is a simple method to produce silica from rice husk (RH). One of the key to obtain higher purity silica from rice husk by calcination method is the effectiveness of impurities removal, especially potassium, from RH surface before calcination process. So, in the present study, an attempt has been made to produce high purity silica powder by using calcination method with the combination of roasting-quenching and acid leaching as a pretreatment to eliminate metal impurities, especially potassium, detected by using inductively coupled plasma mass spectrometry (ICP-MS). Finally, the high purity silica, 99.928% was obtained by roasting and calcination temperature of 300°C and 650°C, respectively. However, by considering less energy usage and silica purity achievement, the combination of 300°C roasting-quenching, 1M hydrochloric acid leaching, and calcination at the temperature of 600°C was the best route.

  9. Modification of Silica Rice Husk Ash to Solid Ammonium Sulphate for Second Generation Biofuels Productions

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    Kasim Mohammed Hello

    2014-01-01

    Full Text Available A new approach has been demonstrated for the synthesis of solid ammonium sulphate attached to silica rice husk ash. The 3-(aminopropyltriethoxysilane was immobilized onto silica at room temperature to functionalize the silica with ammine end groups (–NH2. The amine group was sulphated with sulphuric acid to produce a novel micro-rod-like shaped acidic catalyst (as seen with TEM designated RHNH3SO4H (RH = rice husk. The TGA analysis shows that the catalyst is stable at temperatures below 200°C. The acidity measurement of the catalyst indicates that it has Brønsted acid sites. Cellulose extracted from waste of rice husk and cellulose extracted from office paper were hydrolysed to glucose in 6 h, and the glucose was hydrolysed afterwards to other products within 13 h. The catalyst is reusable many times without a significant loss of catalytic activity.

  10. Covalent immobilization of oxylipin biosynthetic enzymes on nanoporous rice husk silica for production of cis(+)-12-oxophytodienoic acid.

    Science.gov (United States)

    Le, Thu Bao; Han, Chong Soo; Cho, Kyoungwon; Han, Oksoo

    2017-09-11

    Soybean lipoxygenase, recombinant rice allene oxide synthase-1 and rice allene oxide cyclase were covalently immobilized on nanoporous rice husk silica using two types of linkers: glutardialdehyde and polyethylene glycol. The immobilization efficiency achieved using glutardialdehyde-linked rice husk silica was higher than that achieved using polyethylene glycol-linked rice husk silica (50-92% and 25-50%, respectively). Immobilization on both types of matrices significantly decreased the specific activities of the immobilized enzymes. Solid-phase reaction yields of the enzymes were determined relative to the yields observed for the solution-phase reactions. Yields of the solid-phase reactions catalyzed by immobilized soybean lipoxygenase, rice allene oxide synthase-1, and rice allene oxide cyclase ranged from 50% to 230% and were dependent on both the enzymes and linkers used. Production of cis(+)-12-oxophytodienoic acid from α-linolenic acid by consecutive reactions using all three enzymes in a co-immobilization system resulted in 83.6% and 65.1% yields on glutardialdehyde-linked and epichlorohydrin-polyethylene glycol-linked rice husk silica, respectively. Our results suggest that immobilization of biosynthetic enzymes of the octadecanoid pathway on rice husk silica may be an efficient method for the in vitro production of oxylipins. Additionally, enzyme immobilizations on rice husk silica matrices may be more broadly applicable for producing physiologically important compounds in other biosynthetic pathways.

  11. Reinforcement of natural rubber hybrid composites based on marble sludge/Silica and marble sludge/rice husk derived silica

    Science.gov (United States)

    Ahmed, Khalil; Nizami, Shaikh Sirajuddin; Riza, Nudrat Zahid

    2013-01-01

    A research has been carried out to develop natural rubber (NR) hybrid composites reinforced with marble sludge (MS)/Silica and MS/rice husk derived silica (RHS). The primary aim of this development is to scrutinize the cure characteristics, mechanical and swelling properties of such hybrid composite. The use of both industrial and agricultural waste such as marble sludge and rice husk derived silica has the primary advantage of being eco-friendly, low cost and easily available as compared to other expensive fillers. The results from this study showed that the performance of NR hybrid composites with MS/Silica and MS/RHS as fillers is extremely better in mechanical and swelling properties as compared with the case where MS used as single filler. The study suggests that the use of recently developed silica and marble sludge as industrial and agricultural waste is accomplished to provide a probable cost effective, industrially prospective, and attractive replacement to the in general purpose used fillers like china clay, calcium carbonate, and talc. PMID:25685484

  12. Reinforcement of natural rubber hybrid composites based on marble sludge/Silica and marble sludge/rice husk derived silica

    Directory of Open Access Journals (Sweden)

    Khalil Ahmed

    2014-03-01

    Full Text Available A research has been carried out to develop natural rubber (NR hybrid composites reinforced with marble sludge (MS/Silica and MS/rice husk derived silica (RHS. The primary aim of this development is to scrutinize the cure characteristics, mechanical and swelling properties of such hybrid composite. The use of both industrial and agricultural waste such as marble sludge and rice husk derived silica has the primary advantage of being eco-friendly, low cost and easily available as compared to other expensive fillers. The results from this study showed that the performance of NR hybrid composites with MS/Silica and MS/RHS as fillers is extremely better in mechanical and swelling properties as compared with the case where MS used as single filler. The study suggests that the use of recently developed silica and marble sludge as industrial and agricultural waste is accomplished to provide a probable cost effective, industrially prospective, and attractive replacement to the in general purpose used fillers like china clay, calcium carbonate, and talc.

  13. Hexavalent chromium removal in a tannery industry wastewater using rice husk silica

    OpenAIRE

    Sivakumar, D

    2015-01-01

    Present study dealt the removal of Cr(VI) in a tannery industry wastewater using rice husk silica powder as an adsorbent.The experimental investigations have been carried out by using rice husk silica powder for different adsorption dosage, different contact time and different pH against the initial Cr(VI) concentration of 292 mg/L. The maximum percentage removal of Cr(VI) in the tannery industrial wastewater (88.3 %) was found at an optimum adsorbent dosage of 15 g, contact time of 150 min.,...

  14. Rice Husk Ash-Derived Silica Nanofluids: Synthesis and Stability Study.

    Science.gov (United States)

    Zhang, Zhiliang; He, Wenxiu; Zheng, Jianzhong; Wang, Guangquan; Ji, Jianbing

    2016-12-01

    Nanofluids, colloidal suspensions consisting of base fluids and nanoparticles, are a new generation of engineering working fluids. Nanofluids have shown great potential in heat/mass transfer applications. However, their practical applications are limited by the high production cost and low stability. In this study, a low-cost agricultural waste, rice husk ash (RHA), was used as a silicon source to the synthesis of silica nanofluids. First, silica nanoparticles with an average size of 47 nm were synthesized. Next, by dispersing the silica nanoparticles in water with ultrasonic vibration, silica nanofluids were formed. The results indicated that the dispersibility and stability of nanofluids were highly dependent on sonication time and power, dispersant types and concentrations, as well as pH; an optimal experiment condition could result in the highest stability of silica nanofluid. After 7 days storage, the nanofluid showed no sedimentation, unchanged particle size, and zeta potential. The results of this study demonstrated that there is a great potential for the use of RHA as a low-cost renewable resource for the production of stable silica nanofluids. Graphical Abstract Rice husk ash was used as a low-cost renewable resource for production of silica nanofluids with high stability.

  15. Rice Husk Ash as a Renewable Source for the Production of Value Added Silica Gel and its Application: An Overview

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    Ram Prasad

    2012-06-01

    Full Text Available In recent years, silica gels have developed a lot of interest due to their extraordinary properties and their existing and potential applications in science and technology. Silica gel has a wide range of applications such as a desiccant, as a preservation tool to control humidity, as an adsorbent, as a catalyst and as a cata-lyst support. Silica gel is a rigid three-dimensional network of colloidal silica, and is classified as: aqua-gel, alco-gel, xero-gel and aero-gel. Out of all known solid porous materials, aero-gels are particularly known for their high specific surface area, high porosity, low bulk density, high thermal insulation value, ultra low dielectric constant and low index of refraction. Because of these extraordinary properties silica aero-gel has many commercial applications such as thermal window insulation, acoustic barriers, super-capacitors and catalytic supports. However, monolithic silica aero-gel has been used extensively in high energy physics in Cherenkov radiation detectors and in shock wave studies at high pressures, inertial confinement fusion (ICF radio-luminescent and micrometeorites. Silica gel can be prepared by using various sol gel precursors but the rice husk (RH is considered as the cheapest source for silica gel production. Rice husk is a waste product abundantly available in rice producing countries during milling of rice. This review article aims at summarizing the developments carried out so far in synthesis, properties, characterization and method of determination of silica, silica gel, silica aero-gel and silica xero-gel. The effect of synthesis parameters such as pH, temperature of burning the rice husk, acid leaching prior to formation of rice husk ash (RHA on the properties of final product are also described. The attention is also paid on the application of RH, RHA, sil-ica, silica aero-gel and silica xero-gel. Development of economically viable processes for getting rice husk silica with specific

  16. Consecutively Preparing D-Xylose, Organosolv Lignin, and Amorphous Ultrafine Silica from Rice Husk

    Science.gov (United States)

    Zhang, Hongxi; Ding, Xuefeng; Wang, Zichen; Zhao, Xu

    2014-01-01

    Rice husk is an abundant agricultural by-product reaching the output of 80 million tons annually in the world. The most common treatment method of rice husk is burning or burying, which caused serious air pollution and resource waste. In order to solve this problem, a new method is proposed to comprehensively utilize the rice husk in this paper. Firstly, the D-xylose was prepared from the semicellulose via dilute acid hydrolysis. Secondly, the lignin was separated via organic solvent pulping from the residue. Finally, the amorphous ultrafine silica was prepared via pyrolysis of the residue produced in the second process. In this way, the three main contents of rice husk (semicellulose, lignin, and silica) are consecutively converted to three fine chemicals, without solid waste produced. The yields of D-xylose and organosolv lignin reach 58.2% and 58.5%, respectively. The purity and specific surface of amorphous ultrafine silica reach 99.92% and 225.20 m2/g. PMID:25140120

  17. Performance at high temperature of alkali-activated slag pastes produced with silica fume and rice husk ash based activators

    National Research Council Canada - National Science Library

    Bernal, S. A; Rodríguez, E. D; Mejía de Gutiérrez, R; Provis, J. L

    2015-01-01

    This study assessed the mechanical properties, and structural changes induced by high temperature exposure, of alkali-silicate activated slag cements produced with sodium silicates derived from silica fume (SF) and rice husk ash (RHA...

  18. Investigation of silica from rice husk ash wastes as an alternative material for microwave absorbers

    Science.gov (United States)

    Sudiana, I. Nyoman; Mitsudo, Seitaro; Firihu, Muhammad Zamrun; Aba, La; Ngkoimani, La Ode; Arsana, Made Widana; Aripin, Haji

    2017-01-01

    An attempt was made to produce silica from an agricultural waste, i.e. rice husk ash (RHA), for a microwave absorber. The high percentage of silica content from RHA was used as a silica source for sodium silica solutions. Different heating temperatures, times and acid treatments were studied for silica extractions. The composite was characterized and its microwave properties were investigated after sintering from 400 to 1200 °C. The results showed that the existing phases in all compositions at 1200 °C were mullite, cristobalite and Al2O3. The intensities of cristobalite peaks gradually decreased with increased compositions of Al2O3, while the intensities of mullite peaks increased with the increased compositions of Al2O3. Compositions with higher amounts of amorphous silica xerogel showed a lower degree of Al2O3 peaks when compared to other compositions, while the peaks of cristobalite were found to be with greater intensities. A correlation between the structural changes and the microwave properties of the samples in frequencies ranging from 8.2 to 12.4 GHz has been found and discussed. The calculated values showed that the reflection losses decreased as t he sintering temperatures were increased up to 1200 °C. The increasing degree of crystallinity was identified as the main reason for the decrease of the reflection losses since the silica xerogel glass ceramic becomes more transparent to microwaves.

  19. Preparation of an efficient humidity indicating silica gel from rice ...

    Indian Academy of Sciences (India)

    Administrator

    Typically, 5 g dry ash was boiled in 100 ml 1 M. NaOH solution for 1h under reflux condition to dissolve amorphous silica as sodium silicate. The solution was then filtered to separate residue. After cooling to room temperature, the sodium silicate solution was added drop wise into 1 N HCl solution with constant stirring condi-.

  20. Properties of silica from rice husk and rice husk ash and their utilization for zeolite y synthesis

    Directory of Open Access Journals (Sweden)

    Jan-Jezreel F. Saceda

    2011-01-01

    Full Text Available This study compared properties of silica (SiO2 from rice husk (RH and rice husk ash (RHA extracted by acid- and heat-treatment. The SiO2 from RH was in amorphous phase with nearly 100% purity while that from RHA was in crystalline phase with 97.56% purity. Both extracted SiO2 were used in the synthesis of zeolite NaY but that from RH was better due to the efficiency in product recovery and simplicity of extraction. After the NaY was exchanged to NH4Y and calcined to convert to HY, the product did not carry over the textural properties of the parent NaY and NH4Y.

  1. Selectivity of the Cd2+/Ca2+ exchange on modified rice hull silica.

    Science.gov (United States)

    Sánchez-Flores, Norma A; Solache, Marcos; Olguín, M Teresa; Fripiat, José J; Pacheco-Malagón, Graciela; Saniger, José M; Bulbulian, Silvia

    2009-03-01

    The rice hull ash is composed by 94% of SiO2, an agricultural waste that can be recovered and purified by a depolymerization reaction yielding an organo-silicic gel. The purpose of this paper is to show that this silica can be used to fix Cd2+ from aqueous solution. The pH of hydrolysis of the organo-silicic gel is the main factor modifying the distribution between the solid and the solution. The contact time between the Cd2+ solution and the solid was studied to optimize the sorption conditions. The equilibrium measurements were performed after 40 hours at room temperature. The competition with Ca2+ ions in the solutions was also studied in order to evaluate the selectivity of the Cd2+ fixation. It was found that the rice hull ash has a higher capacity to fix Cd2+ than the rice hull derivatives.

  2. Synthesis of belite cement from nano-silica extracted from two rice husk ashes.

    Science.gov (United States)

    Sinyoung, Suthatip; Kunchariyakun, Kittipong; Asavapisit, Suwimol; MacKenzie, Kenneth J D

    2017-04-01

    Nano-silicas extracted from a pure rice husk ash calcined in the laboratory (RHA) and ash from an impure industrial rice husk waste (BRHA), were used to form belite cement by firing with two different calcium sources (calcium carbonate and calcium nitrate). The nano-silica extracted from RHA was highly reactive due to its high pore volume and low activation energy of dehydration. The formation of belite cement from both nano-silicas was studied by firing with two different calcium sources, Ca(NO3)2 and CaCO3 at 800-1100 °C. Both nano-silicas formed the principal phase in belite cement (larnite or β-C2S) at temperatures as low as 800 °C, especially with calcium nitrate as the calcium source. Thus, highly impure BRHA is shown to be very suitable as a starting material for the low-temperature production of belite cement, especially in conjunction with calcium nitrate as the calcium source. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Synthesis and Characterization of Microwave Sintered Silica Xerogel Produced from Rice Husk Ash

    Science.gov (United States)

    Sudiana, I. N.; Mitsudo, S.; Nishiwaki, T.; Susilowati, P. E.; Lestari, L.; Firihu, M. Z.; Aripin, H.

    2016-08-01

    Silica xerogel ceramic produced from rice husk ash (RHA) taken from South East Sulawesi Indonesia has been successfully sintered by using a millimeter waves (MMW) heating system with a 28 GHz gyrotron as radiation source. The ceramic was also sintered by using an electric furnace where served as a comparison. Densification, microstructural, and morphological characterization of the silica were then investigated by using an Archimedes densification measurement method device, a X-ray diffraction (XRD) and a Scanning Electron Microscopy (SEM), respectively. Effect of microwave energy on the properties of silica xerogel ceramic were evaluated and discussed and compared to conventionally sintered results. The notably different densification and microstructure of sintered samples after sintering were found. The results suggest that microwave radiation provides a microwave effect during sintering.

  4. Genetic diversity of high performance cultivars of upland and irrigated Brazilian rice.

    Science.gov (United States)

    Coelho, G R C; Brondani, C; Hoffmann, L V; Valdisser, P A M R; Borba, T C O; Mendonça, J A; Rodrigues, L A; de Menezes, I P P

    2017-09-21

    The objective of this study was to analyze the diversity and discrimination of high-performance Brazilian rice cultivars using microsatellite markers. Twenty-nine rice cultivars belonging to EMBRAPA Arroz e Feijão germplasm bank in Brazil were genotyped by 24 SSR markers to establish their structure and genetic discrimination. It was demonstrated that the analyzed germplasm of rice presents an expressive and significant genetic diversity with low heterogeneity among the cultivars. All 29 cultivars were differentiated genetically, and were organized into two groups related to their upland and irrigated cultivation systems. These groups showed a high genetic differentiation, with greater diversity within the group that includes the cultivars for irrigated system. The genotyping data of these cultivars, with the morphological e phenotypical data, are valuable information to be used by rice breeding programs to develop new improved cultivars.

  5. Occurrence of Aspergillus section Flavi and aflatoxins in Brazilian rice: From field to market.

    Science.gov (United States)

    Katsurayama, Aline M; Martins, Ligia M; Iamanaka, Beatriz T; Fungaro, Maria Helena P; Silva, Josué J; Frisvad, Jens C; Pitt, John I; Taniwaki, Marta H

    2018-02-02

    The guarantee of the high quality of rice is of utmost importance because any toxic contaminant may affect consumer health, especially in countries such as Brazil where rice is part of the daily diet. A total of 187 rice samples, from field, processing and market from two different production systems, wetland from the state of Rio Grande do Sul, dryland, from the state of Maranhão and market samples from the state of São Paulo, were analyzed for fungi belonging to Aspergillus section Flavi and the presence of aflatoxins. Twenty-three soil samples from wetland and dryland were also analyzed. A total of 383 Aspergillus section Flavi strains were isolated from rice and soil samples. Using a polyphasic approach, with phenotypic (morphology and extrolite profiles) and molecular data (beta-tubulin gene sequences), five species were identified: A. flavus, A. caelatus, A. novoparasiticus, A. arachidicola and A. pseudocaelatus. This is the first report of these last three species from rice and rice plantation soil. Only seven (17%) of the A. flavus isolates produced type B aflatoxins, but 95% produced kojic acid and 69% cyclopiazonic acid. Less than 14% of the rice samples were contaminated with aflatoxins, but two of the market samples were well above the maximum tolerable limit (5μg/kg), established by the Brazilian National Health Surveillance Agency. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Can rice field channels contribute to biodiversity conservation in Southern Brazilian wetlands?

    Science.gov (United States)

    Maltchik, Leonardo; Rolon, Ana Silvia; Stenert, Cristina; Machado, Iberê Farina; Rocha, Odete

    2011-12-01

    Conservation of species in agroecosystems has attracted attention. Irrigation channels can improve habitats and offer conditions for freshwater species conservation. Two questions from biodiversity conservation point of view are: 1) Can the irrigated channels maintain a rich diversity of macrophytes, macroinvertebrates and amphibians over the cultivation cycle? 2) Do richness, abundance and composition of aquatic species change over the rice cultivation cycle? For this, a set of four rice field channels was randomly selected in Southern Brazilian wetlands. In each channel, six sample collection events were carried out over the rice cultivation cycle (June 2005 to June 2006). A total of 160 taxa were identified in irrigated channels, including 59 macrophyte species, 91 taxa of macroinvertebrate and 10 amphibian species. The richness and abundance of macrophytes, macroinvertebrates and amphibians did not change significantly over the rice cultivation cycle. However, the species composition of these groups in the irrigation channels varied between uncultivated and cultivated periods. Our results showed that the species diversity found in the irrigation channels, together with the permanence of water enables these man-made aquatic networks to function as important systems that can contribute to the conservation of biodiversity in regions where the wetlands were converted into rice fields. The conservation of the species in agriculture, such as rice field channels, may be an important alternative for biodiversity conservation in Southern Brazil, where more than 90% of wetland systems have already been lost and the remaining ones are still at high risk due to the expansion of rice production.

  7. Extraction of Pb2+ using Silica from Rice Husks Ash (RHA – Chitosan as Solid Phase

    Directory of Open Access Journals (Sweden)

    Hanandayu Widwiastuti

    2013-03-01

    Full Text Available The existence of lead (Pb compounds in waters can be caused of waste pollution from industrial activities such as dye and battery industries. Lead has toxic characteristic and is able to causing deseases. The levels of Cr(VI can be decreased by methods such as electroplating, oxidation, reduction, and membrane separation. But this methods require high cost and produce a lot of waste. Furthermore, those methods cannot determine the small concentration of Pb2+. Therefore, solid phase extraction is used because it’s a simple method and can be used to preconcentrate Pb2+ ion. The aim of this study is to create solid phase from nature material as an alternative method to determine Pb2+ in water samples. The solid phase is silica from rice husks ash (RHA that was modified using chitosan. To achieve that aim, the optimization of silica : chitosan composition was done. The influence of Pb2+ concentration and citric acid concentration was studied to obtain optimum recovery of Pb2+. Interaction between Pb2+ ion and solid phase silica – chitosan could be estimated based on the result. The result showed the optimum composition of silica : chitosan is 65% silica : 35% chitosan with Cation Exchange Capacity (CEC 0.00455 mek/g. Mass Adsorbed Pb2+for 1 g silica : chitosan 65% is 9.715 mg/g. Optimum recovery of Pb2+ on solid phase extraction is reached at concentration of Pb2+ 10 ppm and citric acid concentration 0.05 M (88.25 % and 81.18 %. This result showed that solid phase extraction using silica – chitosan can be used as an alternative method to determine Pb2+ in water.

  8. Lignin isolation process from rice husk by alkaline hydrogen peroxide: Lignin and silica extracted

    Science.gov (United States)

    Ma'ruf, Anwar; Pramudono, Bambang; Aryanti, Nita

    2017-03-01

    Biomass is one of abundance resources in the world. Biomass consists of three main materials such as cellulose, hemicelluloses and lignin. Therefore, biomass can be referred to lignocellulosic material. Both the cellulose and hemicelluloses fractions are polymers of sugars, and thereby a potential source of fermentable sugars, or other processes that convert sugars into products. Lignin is a polymer compound which contains of phenolic compounds. Rice husk is one of biomass, which has high contain of lignin. Rice husk has special characteristics because of silica content. The aim of this paper is to analyze lignin and silica extracted during lignin isolation process of rice husk using alkaline hydrogen peroxide. Three main variables such as solvent/solid ratio, concentration of hydrogen peroxide and pH of the mixture are studied. The optimum conditions for lignin isolation are at solvent/solid ratio 9:1 ml/gr, hydrogen peroxide concentration of 1.5%v and pH of the mixture of 11.

  9. Fabrication of Silica Glass from Rice Husk Ash with Spodumene Additions

    Science.gov (United States)

    Wasanapiarnpong, T.; Vorajesdarom, B.; Rujirakamort, E.; Nilpairach, S.; Mongkolkachit, C.

    2011-10-01

    Silica glass is an interesting material due to its low thermal expansion coefficient, high chemical inertness, and transparency. In this study, low cost rice husk ash waste containing mainly amorphous silica phase was used as a starting raw material. Formation of cristrobalite caused product damage during cooling down was suppressed by an addition of some sintering aids. Spodumene was selected to use as the sintering aid due to its ability to promote the sinterability of the rice husk ash by liquid phase forming. Lithium carbonate and aluminum nitrate were mixed with the rice husk ash as starting chemicals for spodumene forming. To investigate the effects of spodumene addition on densification, physical properties and thermal expansion coefficient, 25 and 50 mass% of spdumene were added to the mixture. Mixed powders were dry pressed into pellet shapes and sintered at 1000-1250 °C for 30 min in an electric furnace. It was found that 50 mass% addition of spodumene enhanced the densification of the specimens sintered at the temperature higher than 1250 °C. Water absorption was reduced to 1.11 % with bulk density of 2.12 g/cm3. Low thermal expansion coefficient of 2.70×10-6 /°C was achieved with only the petalite phase detection.

  10. Fabrication of Silica Glass from Rice Husk Ash with Spodumene Additions

    Energy Technology Data Exchange (ETDEWEB)

    Wasanapiarnpong, T; Vorajesdarom, B; Rujirakamort, E [Research Unit of Advanced Ceramics, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok (Thailand); Nilpairach, S [Metallurgy and Materials Science Research Institute, Chulalongkorn University, Bangkok (Thailand); Mongkolkachit, C, E-mail: thanakorn.w@chula.ac.t [National Metal and Materials Technology Center, Pathumthani (Thailand)

    2011-10-29

    Silica glass is an interesting material due to its low thermal expansion coefficient, high chemical inertness, and transparency. In this study, low cost rice husk ash waste containing mainly amorphous silica phase was used as a starting raw material. Formation of cristrobalite caused product damage during cooling down was suppressed by an addition of some sintering aids. Spodumene was selected to use as the sintering aid due to its ability to promote the sinterability of the rice husk ash by liquid phase forming. Lithium carbonate and aluminum nitrate were mixed with the rice husk ash as starting chemicals for spodumene forming. To investigate the effects of spodumene addition on densification, physical properties and thermal expansion coefficient, 25 and 50 mass% of spdumene were added to the mixture. Mixed powders were dry pressed into pellet shapes and sintered at 1000-1250 deg. C for 30 min in an electric furnace. It was found that 50 mass% addition of spodumene enhanced the densification of the specimens sintered at the temperature higher than 1250 deg. C. Water absorption was reduced to 1.11 % with bulk density of 2.12 g/cm{sup 3}. Low thermal expansion coefficient of 2.70x10{sup -6} /deg. C was achieved with only the petalite phase detection.

  11. Rhizopus oryzae lipase immobilized on hierarchical mesoporous silica supports for transesterification of rice bran oil.

    Science.gov (United States)

    Ramachandran, Prashanth; Narayanan, Guru Krupa; Gandhi, Sakthivel; Sethuraman, Swaminathan; Krishnan, Uma Maheswari

    2015-03-01

    The tunable textural properties of self-oriented mesoporous silica were investigated for their suitability as enzyme immobilization matrices to support transesterification of rice bran oil. Different morphologies of mesoporous silica (rod-like, rice-like, and spherical) were synthesized and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption-desorption isotherms. The surface area, pore size, and ordered arrangement of the pores were found to influence the immobilization and activity of the enzyme in the mesopores. The immobilization in rod-like silica was highest with an immobilization efficiency of 63 % and exhibited minimal activity loss after immobilization. Functionalization of the mesoporous surface with ethyl groups further enhanced the enzyme immobilization. The free enzyme lost most of its activity at 50 °C while the immobilized enzyme showed activity even up to 60 °C. Transesterified product yield of nearly 82 % was obtained for 24 h of reaction with enzyme immobilized on ethyl-functionalized SBA-15 at an oil:methanol ratio of 1:3. Fourier transform infrared spectroscopy (FT-IR) and Gas chromatography-mass spectrometry (GC-MS) were used to characterize the transesterified product obtained. The reusability of the immobilized enzyme was studied for 3 cycles.

  12. Pozzolanic Reactivity of Silica Fume and Ground Rice Husk Ash as Reactive Silica in a Cementitious System: A Comparative Study.

    Science.gov (United States)

    Xu, Weiting; Lo, Tommy Yiu; Wang, Weilun; Ouyang, Dong; Wang, Penggang; Xing, Feng

    2016-03-01

    This study comparably assessed the pozzolanic effect of silica fume (SF) and ground rice husk ash (RHA) as supplementary cementing materials on the properties of blended cement pastes and concretes. A commonly commercial silica fume (SF) and locally-produced rice husk ash (RHA) samples with two finenesses (one with larger size than cement and the other with smaller size than cement) were used in this study. Material properties of SF and RHA were experimentally characterized. Hydration and mechanical properties of cement pastes incorporating SF and RHA were determined by thermogravimetric analysis (TGA) and compressive strength tests, respectively. Properties of concretes regarding workability, mechanical property, durability, and microstructure were evaluated. Results showed that, although the finely ground RHA used in this study possessed lower SiO₂ content and higher particle size compared to SF, it exhibited comparable pozzolanic reactivity with SF due to the nano-scale pores on its each single particle, leading to a higher specific surface area. The optimal replacement levels of SF and RHA were 10% by weight of cement in pastes and concretes. Although addition of SF and RHA led to a significant reduction in slump for the fresh mixtures, inclusion of up to 30% of SF or 15% of ground RHA did not adversely affect the strength of concretes. At the same mix, incorporation of finely-ground RHA in cement composites provided comparable mechanical properties, hydration degree, and durability with SF blended cement composites, owing to the porous structure and high specific surface area of RHA particles. Microstructure morphology analysis of concretes explored by scanning electron microscopy (SEM) further validated the strength and the durability test results.

  13. Pozzolanic Reactivity of Silica Fume and Ground Rice Husk Ash as Reactive Silica in a Cementitious System: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Weiting Xu

    2016-03-01

    Full Text Available This study comparably assessed the pozzolanic effect of silica fume (SF and ground rice husk ash (RHA as supplementary cementing materials on the properties of blended cement pastes and concretes. A commonly commercial silica fume (SF and locally-produced rice husk ash (RHA samples with two finenesses (one with larger size than cement and the other with smaller size than cement were used in this study. Material properties of SF and RHA were experimentally characterized. Hydration and mechanical properties of cement pastes incorporating SF and RHA were determined by thermogravimetric analysis (TGA and compressive strength tests, respectively. Properties of concretes regarding workability, mechanical property, durability, and microstructure were evaluated. Results showed that, although the finely ground RHA used in this study possessed lower SiO2 content and higher particle size compared to SF, it exhibited comparable pozzolanic reactivity with SF due to the nano-scale pores on its each single particle, leading to a higher specific surface area. The optimal replacement levels of SF and RHA were 10% by weight of cement in pastes and concretes. Although addition of SF and RHA led to a significant reduction in slump for the fresh mixtures, inclusion of up to 30% of SF or 15% of ground RHA did not adversely affect the strength of concretes. At the same mix, incorporation of finely-ground RHA in cement composites provided comparable mechanical properties, hydration degree, and durability with SF blended cement composites, owing to the porous structure and high specific surface area of RHA particles. Microstructure morphology analysis of concretes explored by scanning electron microscopy (SEM further validated the strength and the durability test results.

  14. The impact of wood biochar as a soil amendment in aerobic rice systems of the Brazilian Savannah

    NARCIS (Netherlands)

    Carvalho, M.T.M.

    2015-01-01

    Abstract Keywords: tropical Savannah, biochar, soil fertility, aerobic rice, grain yield, N2O emission Márcia Thaís de Melo Carvalho (2015). The impact of wood biochar as a soil amendment in aerobic rice systems of the Brazilian Savannah. PhD thesis, Wageningen

  15. Hexavalent chromium removal in a tannery industry wastewater using rice husk silica

    Directory of Open Access Journals (Sweden)

    D. Sivakumar

    2015-01-01

    Full Text Available Present study dealt the removal of Cr(VI in a tannery industry wastewater using rice husk silica powder as an adsorbent.The experimental investigations have been carried out by using rice husk silica powder for different adsorption dosage, different contact time and different pH against the initial Cr(VI concentration of 292 mg/L. The maximum percentage removal of Cr(VI in the tannery industrial wastewater (88.3 % was found at an optimum adsorbent dosage of 15 g, contact time of 150 min., and pH of 4.  Further, the experimental data on removal of Cr(VI from tannery industry wastewater was validated with the Cr(VI aqueous solution of same initial concentration of tannery industry waster against the optimum process parameters. The results of the validation experiment showed that the experiments conducted for the removal of Cr(VI in a tannery industry wastewater may be reproducing capability for analyzing various parameters along with Cr(VI based water and industry wastewater.  The experimental data were fitted to Langmuir and Freundlich isotherm models.  Isotherm models result indicated that the equilibrium data fitted well with the Langmuir isotherm than Freundlich isotherm, because of higher correlation created between dependent and independent variables. Thus, the adsorption method using rice husk silica powder was used effectively for removing Cr(VI in the tannery industrial wastewater, seems to be an economical and worthwhile alternative over other conventional methods, because of their abundant source, low price, multi-purposes and antimicrobial properties.

  16. ACIDITY OF MODIFIED MORDENITES SYNTHESIZED FROM RICE HUSK SILICA AND CATALYTIC TRANSFORMATION OF METHYLBUTYNOL

    Directory of Open Access Journals (Sweden)

    Sittichai Kulawong

    2015-02-01

    Full Text Available Mordenite (MOR was synthesized using rice husk silica and modified by base (B, acid (A or acid-base (AB and converted to H-form. The modification did not destroy the MOR structure but increased surface area and generated mesopores. Lewis acidity of the parent and modified MOR samples investigated by aluminum NMR and NH3-TPD showed a decrease in the following order: HMOR > BMOR > ABMOR > AMOR. For the catalytic transformation of methylbutynol, ABMOR provided the highest conversion and selectivity of products from acid sites.

  17. Characterization of silica distribution in rice husk using Synchrotron Radiation µCT and its implications for archaeological interpretation.

    Science.gov (United States)

    Wu, Yan; Yang, Yimin; Xiao, Tiqiao; Gu, Zhou; Hill, David V; Wang, Changsui

    2014-10-01

    This article reports the results of a pilot project using Synchrotron Radiation µCT (computer-aided tomography) to examine the distribution of silica within phytoliths from rice husks. Experiments indicate that computed tomography can be used to show how silica accumulates and is distributed in a distinctive zigzag pattern of long epidermal cells that are characteristic of phytoliths from rice husks. This method will help us to understand why the dry ashing method produced much more zigzag pattern of long cells phytoliths from rice husk than did the acid extraction method. Besides, the zigzag morphological pattern exhibited by long epidermal cells is characteristic of this species which makes it useful in the identification of rice husks from archaeological contexts and indicating heating process. © 2014 Wiley Periodicals, Inc.

  18. Improvement of physical and chemical properties of concrete with brazilian silica rice husk (SRH La mejora de propiedades físicas y químicas de hormigón con silice de cáscara de arroz (SRH brasileña

    Directory of Open Access Journals (Sweden)

    Fernanda Giannotti da Silva

    2008-04-01

    Full Text Available The use of industrial and agricultural waste substitutions for Portland cement has greatly contributed to sustainable development practices. The increase in cement demand will be met by the use of supplementary cementing materials, in order to minimize the clinker consumption. In this study, the effects of silica extracted from rice husk (SRH as a partial replacement of cement in concretes with low water/binder are reported. The properties investigated include compressive strength, splitting tensile strength, water absorption by immersion, water absorption by capillarity and resistance to chloride ion penetration. The research indicates that SRH is an effective mineral addition for designing durable concrete presenting an optimal performance when the replacement ratio of Portland cement is around 10%El uso de desechos industriales y agrícolas como segmento en la producción de cemento Portland ha contribuido de manera importante en la práctica de desarrollo sustentable. El aumento en la demanda de cemento coincide con el uso de materiales aglomerantes suplementarios para minimizar el consumo de clinker. En este estudio, se informan los efectos de la sustitución parcial de cemento Portland por sílice extraído de la cascara de arroz (SRH en hormigones con baja relación agua/materiales cementicios. Las propiedades investigadas incluyen resistencia a la compresión, resistencia a la tracción, absorción de agua por inmersión, absorción de agua por capilaridad y resistencia a la penetración de iones de cloruro. La investigación indica que SRH es una adición mineral eficaz para el diseño de hormigones durables que presenta una actuación óptima cuando la proporción del reemplazo de cemento de Portland está alrededor de 10%

  19. The impact of wood biochar as a soil amendment in aerobic rice systems of the Brazilian Savannah

    OpenAIRE

    CARVALHO, M. T. de M.

    2015-01-01

    Abstract Keywords: tropical Savannah, biochar, soil fertility, aerobic rice, grain yield, N2O emission Márcia Thaís de Melo Carvalho (2015). The impact of wood biochar as a soil amendment in aerobic rice systems of the Brazilian Savannah. PhD thesis, Wageningen University, The Netherlands, with summaries in English, Dutch and Portuguese,  160 pp. Rice is a staple food for 3 billion people in the world. In Brazil, rice is a traditional staple food mostly cultivated by smallh...

  20. Comparison between rice husk ash and commercial silica as filler in polymeric composites; Comparacao de cinza de casca de arroz e silica comercial como carga em compositos polimericos

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, I.J.; Calheiro, D.; Santos, E.C.A. dos; Oliveira, R.; Rocha, T.L.A.C.; Moraes, C.A.M., E-mail: ijk.fernandes@gmail.com [Universidade do Vale do Rio dos Sinos (UNISINOS), Sao Leopoldo, RS (Brazil). Pos-Graduacao em Engenharia Civil

    2014-07-01

    The use of rice husk ash (RHA) as filler in polymeric materials has been studied in different polymers. Research reported that RHA may successfully replace silica. The silica production process using ore demands high energy input and produces considerable amounts of waste. Therefore, the replacement of silica by RHA may be economically and environmentally advantageous, reducing environmental impact and adding value to a waste material. In this context, this study characterizes and compares RHA of different sources (travelling grate reactor and fluidized bed reactor) with commercially available silicas to assess performance as filler in polymeric materials. Samples were characterized by X-ray fluorescence, loss on ignition, X-ray diffraction, grain size, specific surface area and specific weight. The results show that RHA may be used as a filler in several polymeric materials.(author)

  1. A new method of utilizing rice husk: consecutively preparing D-xylose, organosolv lignin, ethanol and amorphous superfine silica.

    Science.gov (United States)

    Zhang, Hongxi; Ding, Xuefeng; Chen, Xue; Ma, Yuejia; Wang, Zichen; Zhao, Xu

    2015-06-30

    Rice husk is an abundant agricultural by-product with the annual output of 120 and 40 million tons in the world and China, respectively. The common disposal method of rice husk in China has caused the pollution. This manuscript deals with a new method of comprehensively utilizing rice husk, by which hazardous materials are avoided to release. 100.3, 219.4, 50.1 and 170.5 g of D-xylose, organosolv lignin, ethanol and superfine silica are consecutively prepared from 1000 g of rice husk. This new method is helpful to resolving the problem of pollution and waste aroused by rice husk. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Exogenous application of calcium and silica alleviates cadmium toxicity by suppressing oxidative damage in rice seedlings.

    Science.gov (United States)

    Srivastava, Rajneesh Kumar; Pandey, Poonam; Rajpoot, Ritika; Rani, Anjana; Gautam, Arti; Dubey, R S

    2015-07-01

    The present study was undertaken to examine the possible roles of calcium (Ca(2+)) and silica (Si) in protection against oxidative damage due to Cd(2+) toxicity in rice (Oryza sativa L.) seedlings grown in hydroponics. Rice seedlings raised for 12 days in hydroponics containing Cd(NO3)2 (75 μM) showed reduced growth; increase in the level of reactive oxygen species (ROS) (O2 (·-) and H2O2), thiobarbituric acid reactive substances (TBARSs) and protein carbonylation; and increase in the activity of antioxidant enzymes-superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (GPX) compared to untreated controls. Exogenously added Ca(2+) (2 mM) and Si (200 μM) significantly alleviated negative effect of Cd(2+) by restoration of growth of the seedlings, suppression of Cd(2+) uptake and restoration of root plasma membrane integrity. The levels of O2 (·-), H2O2, lipid peroxidation and protein carbonyls were much lower when Ca(2+) and Si were added in the growth medium along with Cd(2+) as compared to Cd-alone-treated seedlings. Ca(2+) and Si lowered Cd-induced increase in SOD, GPX and APX activities while they elevated Cd-induced decline in CAT activity. Using histochemical staining of O2 (·-) and H2O2 in leaf tissues, it was further confirmed that added Ca(2+) and Si suppressed Cd-induced accumulation of O2 (·-) and H2O2 in the leaves. The results suggest that exogenous application of Ca(2+) and Si appears to be advantageous for rice plants in alleviating Cd(2+) toxicity effects by reducing Cd(2+) uptake, decreasing ROS production and suppressing oxidative damage. The observations indicate that Ca(2+) and Si treatments can help in reducing Cd(2+) toxicity in rice plants.

  3. Characterization of anatomical features and silica distribution in rice husk using microscopic and micro-analytical techniques

    Energy Technology Data Exchange (ETDEWEB)

    Park, B.-D.; Wi, S.G.; Lee, K.H.; Singh, A.P.; Yoon, T.-H.; Kim, Y.S

    2003-09-01

    Rice husk is a by-product of rice milling process, and a great resource as a raw biomass material for manufacturing value-added composite products. One of the potential applications is to use rice husk as filler for manufacturing lignocellulosic fiber-thermoplastic composites. This study was conducted to examine the silica distribution in rice husk in preparation to use it as reinforcing filler for thermoplastic polymers. Microscopic techniques, such as light microscopy, scanning electron microscopy and field-emission SEM (FE-SEM) were used to observe the surface and internal structure of rice husk. Microscopic examination showed that two main components of husk, lemma and palea consisted of outer epidermis, layers of fibers, vascular bundles, parenchyma cells, and inner epidermis, in sequence from the outer to the inner surface. Histochemical staining showed that epidermal and fiber cell walls were lignified, and the walls of parenchyma and lower epidermal cells were not lignified. The outer epidermal walls were extremely thick, highly convoluted and lignified. The outer surface of both lemma and palea were conspicuously ridged. The energy dispersive X-ray micro-analysis attached to the FE-SEM provided information on the distribution of silica in the husk. Most of the silica was present in the outer epidermal cells, being particularly concentrated in the dome-shaped protrusions. These observations provided valuable background information on the organization of husk tissues and the distribution of silica, which will help optimize processes related to the use of rice husk for making lignocellulosic fiber-thermoplastic composites in our future work.

  4. Rice Husk Silica-Derived Nanomaterials for Battery Applications: A Literature Review.

    Science.gov (United States)

    Shen, Yafei

    2017-02-08

    Silica-rich rice husk (RH) is an abundant and sustainable agricultural waste. The recovery of value-added products from RH or its ash to explore an economic way for the valorization of agricultural wastes has attracted wide attention. For instance, RH can be converted to biofuels and biochars simultaneously via thermochemical processes. In general, the applications of RH biochars include soil remediation, pollutant removal, silicon battery materials, and so forth. This review concludes recent progress in the synthesis of RH-derived silicon materials for lithium-ion battery (LIB) applications. Silica nanomaterials produced from RH are initially discussed. RH amorphous silica can also be fabricated to crystal silicon used for battery materials via widely used magnesiothermic reduction. However, the RH-derived Si nanoparticles suffer from a low Coulombic efficiency in the initial charge/discharge and limited cycle life as anode materials due to high surface reactions and low thermodynamic stability. The synthesis of Si materials with nano/microhierarchical structure would be an ideal way to improve their electrochemical performances. Embedding nano-Si into 3D conductive matrix is an effective way to improve the structural stability. Among the Si/carbon composite materials, carbon nanotubdes (CNTs) are a promising matrix due to the wired morphology, high electronic conductivity, and robust structure. Additionally, CNTs can easily form 3D cross-linked conducting networks, ensuring effective electron transportation among active particles. Si nanomaterials with microhierarchical structures in which CNTs are tightly intertwined between the RH-derived Si nanoparticles have been proven to be ideal LIB anode materials.

  5. Biochar improves fertility of a clay soil in the Brazilian Savannah: short term effects and impact on rice yield

    Directory of Open Access Journals (Sweden)

    Marcia Thais de Melo Carvalho

    2013-12-01

    Full Text Available The objective of this study was to report single season effects of wood biochar (char application coupled with N fertilization on soil chemical properties, aerobic rice growth and grain yield in a clayey Rhodic Ferralsol in the Brazilian Savannah. Char application effected an increase in soil pH, K, Ca, Mg, CEC, Mn and nitrate while decreasing Al content and potential acidity of soils. No distinct effect of char application on grain yield of aerobic rice was observed. We believe that soil properties impacted by char application were inconsequential for rice yields because neither water, low pH, nor the availability of K or P were limiting factors for rice production. Rate of char above 16 Mg ha^(−1 reduced leaf area index and total shoot dry matter by 72 days after sowing. The number of panicles infected by rice blast decreased with increasing char rate. Increased dry matter beyond the remobilization capacity of the crop, and high number of panicles infected by rice blast were the likely cause of the lower grain yield observed when more than 60 kg N ha^(−1 was applied. The optimal rate of N was 46 kg ha^(−1 and resulted in a rice grain yield above 3 Mg ha^(−1.

  6. Effect of leaching with 5-6 N H2SO4 on thermal kinetics of rice husk during pure silica recovery.

    Science.gov (United States)

    Ali, Muhammad; Ul Haq, Ehsan; Abdul Karim, Muhammad R; Ahmed, Sajjad; Ibrahim, Ather; Ahmad, Waheed; Baig, Waqas M

    2016-01-01

    Rice husk is a potential source for renewable energy and silica. To extract the maximum amount of silica, usually the rice husk is treated with strong acids that burn the organic part leaving behind a black residue. In this research, sulfuric acid is used as an oxidizing agent. Efforts are focused to find out more about the behavior of acid-treated rice husk by using thermal exposure, and results are compared with results for raw rice husk which is thermally exposed but not acid treated. Reaction ratio of rice husk combustion and energy of activation were calculated using the thermogravimetric data. Acid treatment was found influential in initiating degradation earlier compared to raw husk and an overall increase in value of activation energy was observed when heating rate was increased.

  7. Effect of leaching with 5–6 N H2SO4 on thermal kinetics of rice husk during pure silica recovery

    Science.gov (United States)

    Ali, Muhammad; Ul Haq, Ehsan; Abdul Karim, Muhammad R.; Ahmed, Sajjad; Ibrahim, Ather; Ahmad, Waheed; Baig, Waqas M.

    2015-01-01

    Rice husk is a potential source for renewable energy and silica. To extract the maximum amount of silica, usually the rice husk is treated with strong acids that burn the organic part leaving behind a black residue. In this research, sulfuric acid is used as an oxidizing agent. Efforts are focused to find out more about the behavior of acid-treated rice husk by using thermal exposure, and results are compared with results for raw rice husk which is thermally exposed but not acid treated. Reaction ratio of rice husk combustion and energy of activation were calculated using the thermogravimetric data. Acid treatment was found influential in initiating degradation earlier compared to raw husk and an overall increase in value of activation energy was observed when heating rate was increased. PMID:26843969

  8. SYNTHESIS OF ZEOLITE SOCONY MOBIL FROM BLUE SILICA GEL AND RICE HUSK ASH AS CATALYSTS FOR HYDROTHERMAL LIQUEFACTION

    Directory of Open Access Journals (Sweden)

    SUYITNO

    2015-08-01

    Full Text Available Renewable biofuels produced by the hydrothermal liquefaction of rice husks have received much attention because of rapid increases in fuel consumption and corresponding declines in fossil fuel resources. To increase biofuel yields, template-free syntheses of Zeolite Socony Mobil (ZSM catalysts based on blue silica gel and rice husk ash as silica sources were studied. After ZSM synthesis in a closed reactor at 170°C, the crystallinity and crystalline diameters of the products were determined by X-ray diffraction, affording values of 56.33%– 65.81% and 64.3–68.5 nm, respectively. The hydrothermal liquefaction of rice husks with or without a catalyst was conducted in a closed reactor (1200 mm length × 100 mm diameter at 275°C for 45 min. The light biofuel was separated from the ethanol solvent and heavy biofuel via vacuum evaporation. The ZSM catalysts increased the biofuel yields by 2.9%–6.0%. The light biofuels exhibited heating values, flash points, and viscosities of approximately 4.2–4.3 kcal·g−1, 19°C, and 1.48–1.52 cSt, respectively. However, further studies are required to enhance the activity of the ZSMs and increase the quality of the biofuels.

  9. RICE HUSK SILICA-COATED MAGNETIC PARTICLES AS A LOW COST SUPPORT MATERIAL FOR CRUDE Pseudomonas aeruginosa LIPASE IMMOBILIZATION

    Directory of Open Access Journals (Sweden)

    Noor Hindryawati

    2016-11-01

    Full Text Available In this research, lipase produced from the bacteria Pseudomonas aeruginosa was immobilized on rice husk silica-coated Fe3O4 nanoparticles. The process included the following steps: preparation of magnetic ferosoferic oxide nanoparticles (NP, coating NP with silica from rice husk ash, activation with glutaraldehyde and covalent immobilization of lipase on the support. The synthesis of the nanoparticle was followed by characterization through FT-IR, XRD, and FE-SEM. The hydrolysis kinetics (using 4-Nitrophenyl palmitate as a substrate of the immobilized lipase followed Michaelis-Menten model with a Vmax and a Km value of 4.0 mM.s-1 and 0.63 mM, respectively. The immobilized lipase showed better tolerance to extreme temperature and pH compared to free lipase. About 60% of enzyme remained immobilized after ten cycles of reuse and 68.13% of it were stable until 49 days. Thus the silica-coated Fe3O4 nanoparticles appeared to be a potential support material for lipase immobilization applications.

  10. Transesterification of used cooking oil over alkali metal (Li, Na, K supported rice husk silica as potential solid base catalyst

    Directory of Open Access Journals (Sweden)

    Noor Hindryawati

    2014-06-01

    Full Text Available Investigation was conducted on three alkali metals (Li, Na, and K supported by rice husk silica as catalysts for methyl esters production. A simple pseudo-heterogeneous transesterification process of used cooking oil with methanol was conducted to produce methyl esters using calcined alkali metal supported rice husk silica as a solid catalyst. Alkali metal silicate catalysts showed longer lasting activity than the traditional alkali catalysts. The optimum conditions for the process were: alkali metals silicate calcination temperature 500 °C, time 3 h; catalyst amount 3%; methanol to oil molar ratio 9:1; and a reaction temperature of 65 °C. The process was able to transesterify oil to methyl esters in the range of 96.5–98.2% in 1 h for all series. The catalyst is able to tolerant free fatty acid and moisture up to 1.25% and 1.75%, respectively. The catalyst was easily separated from the reaction mixture by filtration and able to reuse six times. The final product met the selected biodiesel fuel properties in accordance with European Standard (EN 14214.

  11. Synthesis of Si/MgO/Mg2SiO4 Composite from Rice Husk-Originated Nano-Silica

    Directory of Open Access Journals (Sweden)

    Maryam Azadeh

    2016-12-01

    Full Text Available Silica exists in Rice husk, an agriculture waste, as a naturally occurring phase. In first step, acidic pre-treatment and calcination of the rice husk were performed to obtain nano-silica, in which various sizes of the nano-silica, totally with sizes under 80 nm, were achieved. Second, to reduce nano-silica to elemental Si and subsequently formation of the composite, Mg used as the reducing agent. In this work, the as-obtained composite mainly is the product of magnesiothermic reduction reaction of the nano-silica, which finally resulted in formation of elemental Si (silicon, MgO (magnesia and Mg2SiO4 (magnesium silicate. The as-synthesized composite can be used as anode in lithium ion batteries. The products in each step were characterized using X-ray powder diffraction (XRD and scanning electron microscopy (FESEM and HRSEM techniques. X-ray powder diffraction patterns confirmed the formation of almost amorphous silica while the FE-SEM images were representing the spherical silica particles at various calcination temperatures. After the magnesiothermic reduction process, HRSEM micrographs indicated the formation of Si-MgO-Mg2SiO4 composite with particle sizes of 180-300 nm. The phase composition analysis was calculated by Rietveld method The electrical response of the Si/MgO/Mg2SiO4 composite was measured to be of 6×108 Ω.m resulted from I-V measurement.

  12. Can rice field channels contribute to biodiversity conservation in Southern Brazilian wetlands?

    Directory of Open Access Journals (Sweden)

    Leonardo Maltchik

    2011-12-01

    species in agroecosystems has attracted attention. Irrigation channels can improve habitats and offer conditions for freshwater species conservation. Two questions from biodiversity conservation point of view are: 1 Can the irrigated channels maintain a rich diversity of macrophytes, macroinvertebrates and amphibians over the cultivation cycle? 2 Do richness, abundance and composition of aquatic species change over the rice cultivation cycle? For this, a set of four rice field channels was randomly selected in Southern Brazilian wetlands. In each channel, six sample collection events were carried out over the rice cultivation cycle (June 2005 to June 2006. A total of 160 taxa were identified in irrigated channels, including 59 macrophyte species, 91 taxa of macroinvertebrate and 10 amphibian species. The richness and abundance of macrophytes, macroinvertebrates and amphibians did not change significantly over the rice cultivation cycle. However, the species composition of these groups in the irrigation channels varied between uncultivated and cultivated periods. Our results showed that the species diversity found in the irrigation channels, together with the permanence of water enables these man-made aquatic networks to function as important systems that can contribute to the conservation of biodiversity in regions where the wetlands were converted into rice fields. The conservation of the species in agriculture, such as rice field channels, may be an important alternative for biodiversity conservation in Southern Brazil, where more than 90% of wetland systems have already been lost and the remaining ones are still at high risk due to the expansion of rice production. Rev. Biol. Trop. 59 (4: 1895-1914. Epub 2011 December 01.

  13. Analysis and risk estimates to workers of Brazilian granitic industries and sandblasters exposed to respirable crystalline silica and natural radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Estellita, L. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal Milton Tavares de Souza, s/n, Gragoata, 24210-340 Niteroi, RJ (Brazil); Santos, A.M.A. [Fundacao Jorge Duprat Figueiredo de Seguranca e Medicina do Trabalho, Fundacentro, C.P. 11484, 05499-970 Sao Paulo, SP (Brazil); Anjos, R.M., E-mail: meigikos@if.uff.b [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal Milton Tavares de Souza, s/n, Gragoata, 24210-340 Niteroi, RJ (Brazil); Yoshimura, E.M. [Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, 05314-970 Sao Paulo, SP (Brazil); Velasco, H. [Grupo de Estudios Ambientales - IMASL. Universidad Nacional de San Luis / CONICET. Ej. de los Andes 950, D5700HHW San Luis (Argentina); Silva, A.A.R. da [Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, 05314-970 Sao Paulo, SP (Brazil); Aguiar, J.G. [Fundacao Jorge Duprat Figueiredo de Seguranca e Medicina do Trabalho, Fundacentro, C.P. 11484, 05499-970 Sao Paulo, SP (Brazil)

    2010-02-15

    Occupational exposure to respirable crystalline silica and to radiation emitted by natural radionuclides present both in rocks and sands was studied in the Brazilian extractive process and granite product manufacture. Respirable airborne dust samples were collected in working environments, where workers perform different tasks with distinct commercial granites types, and also in places where sandblasters work with sands from different origins. The free crystalline silica contents were determined using X-ray diffraction of the respirable particulate fraction of each sample. Dust samples from granite cutting and sandblasting ambient had the natural radionuclides concentrations measured by gamma spectrometry. Dust concentrations in the workplaces were quite variable, reaching values up to 10 times higher than the respirable particle mass threshold limit value (TLV) set by the American Conference for Governmental Industrial Hygienists of 3 mg m{sup -3}. Also the free crystalline silica concentrations were high, reaching values up to 48 times the TLV of 0.025 mg m{sup -3}. Additionally, our results suggest that the risk of radiation-induced cancer in the granite or marble industries is negligible. However, the combined exposure to dust, gamma radiation, and radon daughter products could result in the enhancement of lung cancer risks associated to sandblasting activities.

  14. Catalytic performance of organically templated nano nickel incorporated-rice husk silica in hydroconversion of cyclohexene and dehydrogenation of ethanol

    Directory of Open Access Journals (Sweden)

    Salah A. Hassan

    2013-06-01

    Full Text Available Rice husk silica (RHS was extracted from local rice husk by acid digestion and burning at 650 °C. RHS-Ni catalyst was prepared by dissolving RHS in 1 N NaOH and titrating with 3 N HNO3 containing 10 wt.% Ni2+. The organic modifiers, either p-amino benzoic acid (A or p-phenylenediamine (PDA were incorporated in 5 wt.% and reduced in H2 flow. Investigation of the three catalysts, (RHS-NiR350, (RHS-Ni–AR350 and (RHS-Ni–PDAR350, confirmed good dispersion of Ni nanoparticles; all catalysts were amorphous. The BET surface areas increased in the order: (RHS-NiR350  150 °C, the backward dehydrogenation pathway was more favored, due to unavailability of H2; the process became structure-sensitive. In ethanol conversion, the prevailing dehydrogenation activity of organically modified catalyst samples was encouraged by improved homogeneous distribution of Ni nanoparticles and created micropre system.

  15. Preparation and characterization of electron-beam treated HDPE composites reinforced with rice husk ash and Brazilian clay

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, A.V., E-mail: angelortiz@ipen.br [Nuclear and Energy Research Institute, IPEN-CNEN/SP Av. Prof. Lineu Prestes 2242, São Paulo, SP 05508-000 (Brazil); Teixeira, J.G.; Gomes, M.G.; Oliveira, R.R. [Nuclear and Energy Research Institute, IPEN-CNEN/SP Av. Prof. Lineu Prestes 2242, São Paulo, SP 05508-000 (Brazil); Díaz, F.R.V. [Metallurgical and Materials Engineering Department, Polytechnic School, University of São Paulo Av. Prof. Mello de Morais 2463, São Paulo, SP 05508-900 (Brazil); Moura, E.A.B. [Nuclear and Energy Research Institute, IPEN-CNEN/SP Av. Prof. Lineu Prestes 2242, São Paulo, SP 05508-000 (Brazil)

    2014-08-15

    Highlights: • We examine changes in HDPE properties when waste and clay are used as reinforcement. • The addition of only 3% of clay leads to important gains in HDPE properties. • The use of electron-beam contributes to greater improvements in material properties. • We observe 85% of cross-linking degree for the HDPE when treated with e-beam. - Abstract: This work evaluates the morphology, mechanical and thermo-mechanical properties of high density polyethylene (HDPE) composites. HDPE reinforced with rice husk ashes (80:20 wt%), HDPE reinforced with clay (97:3 wt%) and HDPE reinforced with both rice husk ashes and clay(77:20:3 wt%) were obtained. The Brazilian bentonite chocolate clay was used in this study. This Brazilian smectitic clay is commonly used to produce nanocomposites. The composites were produced by melting extrusion process and then irradiation was carried out in a 1.5 MeV electron-beam accelerator (room temperature, presence of air). Comparisons using the irradiated and non-irradiated neat polymer, and the irradiated and non-irradiated composites were made. The materials obtained were submitted to tensile, flexural and impact tests. Additionally HDT, SEM and XRD analyses were carried out along with the sol–gel analysis which aimed to assess the cross-linking degree of the irradiated materials. Results showed great improvement in most HDPE properties and a high cross-linking degree of 85% as a result of electron-beam irradiation of the material.

  16. A Tribal Story Written in Silica: Using Phytoliths to Research the Effects of Mining on Past Wild Rice (Zizania palustris) Abundance in Sandy Lake, Minnesota

    Science.gov (United States)

    Clarke, I. R.; Jones, M. A.; Yost, C. L.; Drake, C.; Ladwig, J. L.; Myrbo, A.; Howes, T.

    2014-12-01

    Wild rice (Zizania palustris, manoomin) is an emergent aquatic plant that grows annually in the northern Great Lakes region of North America. This region is also rich in iron ore deposits and correspondingly has an extensive history of mining activities. Wild rice no longer grows in some areas where it was previously abundant. Sandy Lake, located in St. Louis County on federally protected lands that are ceded territory of the Fond du Lac Band of Lake Superior Chippewa in Minnesota and downstream of the nearby U.S. Steel Minntac mine, was selected as a test site. This lake has a history of ricing activities by the Ojibwe (Chippewa) People, for whom manoomin has cultural importance. Lake cores were taken on June 17, 2014 by LacCore and FDLRM staff and samples were obtained. This project used phytolith analysis to answer the question of past wild rice presence and abundance in Sandy Lake. Phytoliths are microscopic opal silica deposits produced in some plants. Zizania palustris produces phytolith morphotypes that are unequivocally diagnostic of this species in this region. Microscopic slides were prepared and analyzed for wild rice phytoliths. Concentration values ranged from 25 to 4379 phytoliths per cm3/year, and wild rice accumulation figures ranged from 7 to 789 phytoliths/cm2/year, the maximum values of which occurred in the 1920s and generally declined to the current lowest levels observed. Mining has likely impacted wild rice populations by causing increased sulfate levels and possibly contributing to higher lake levels.

  17. Occurrence of Aspergillus section Flavi and aflatoxins in Brazilian rice: From field to market

    DEFF Research Database (Denmark)

    Katsurayama, Aline M.; Martins, Ligia Manoel; Iamanaka, Beatriz T.

    2018-01-01

    The guarantee of the high quality of rice is of utmost importance because any toxic contaminant may affect consumer health, especially in countries such as Brazil where rice is part of the daily diet. A total of 187 rice samples, from field, processing and market from two different production...... systems, wetland from the state of Rio Grande do Sul, dryland, from the state of Maranhão and market samples from the state of São Paulo, were analyzed for fungi belonging to Aspergillus section Flavi and the presence of aflatoxins. Twenty-three soil samples from wetland and dryland were also analyzed....... A total of 383 Aspergillus section Flavi strains were isolated from rice and soil samples. Using a polyphasic approach, with phenotypic (morphology and extrolite profiles) and molecular data (beta-tubulin gene sequences), five species were identified: A. flavus, A. caelatus, A. novoparasiticus, A...

  18. Rice husk ash as a source of silica in alkali-activated fly ash and granulated blast furnace slag systems

    Directory of Open Access Journals (Sweden)

    Mejía, J. M.

    2013-09-01

    Full Text Available This study assesses the viability of using an agro-industrial by-product, rice husk ash (RHA from a Colombian rice company’s combustion facility, as a total replacement for the commercial sodium silicate ordinarily used in alkaliactivated binders. Fly ash (FA, granulated blast furnace slag (GBFS and binary 50FA:50GBFS blended pastes were activated with a mix of sodium hydroxide and either sodium silicate or one of two types of RHA. The pastes were characterised for strength, mineralogy and microstructure. The findings showed that the agro-industrial by-product can be used to yield alkali-activated materials with 7-day mechanical strengths on the order of 42 MPa. The study confirmed that both amorphous silica and part of the crystalline silica present in RHA participate in the alkaline activation process, providing the alkalinity is suitably adjusted.Este estudio evalúa la viabilidad de utilizar un subproducto agroindustrial, la ceniza de cascarilla de arroz (RHA proveniente de un equipo combustor de una empresa Arrocera en Colombia, como reemplazo total de la sílice aportada por el silicato de sodio comercial en sistemas cementicios activados alcalinamente. Se prepararon pastas de ceniza volante (FA, de escoria de alto horno (GBFS y un sistema binario 50FA:50GBFS, que fueron activadas por una mezcla de silicato de sodio e hidróxido de sodio, y por dos tipos de RHA. Las mezclas se caracterizaron mecánica, mineralógica y microestructuralmente. Los resultados demuestran que es posible obtener materiales activados alcalinamente con resistencias mecánicas del orden de 42 MPa, a 7 días de curado, utilizando el subproducto agroindustrial. Este estudio corrobora que tanto la sílice amorfa como parte de la sílice cristalina presente en RHA tienen la posibilidad de participar en el proceso de activación alcalina, siempre y cuando las condiciones de alcalinidad estén adecuadamente ajustadas.

  19. Nano Silica with High Surface Area from Rice Husk as a Support for 12-Tungstophosphoric Acid: An Efficient Nano Catalyst in Some Organic Reactions%Nano Silica with High Surface Area from Rice Husk as a Support for 12-Tungstophosphoric Acid:An Efficient Nano Catalyst in Some Organic Reactions

    Institute of Scientific and Technical Information of China (English)

    Ezzat RAFIEE; Shabnam SHAHEBRAHIMI

    2012-01-01

    Nano silica was prepared from rice husk with high surface area.X-ray diffraction (XRD) pattern showed that the amorphous form of silica was produced.Chemical composition of the nano silica was estimated by X-ray fluorescence spectroscopy and CHN analysis.The nano silica was used as a support for H3PW12O40.The nano silica and nano silica supported H3PW12O40were characterized by inductively coupled plasma,XRD,transmission electron microscopy (TEM),N2 adsorption-desorption,and Fourier transform infrared spectroscopy.TEM images of nano silica as well as the supported catalyst displayed average size of 6 and 7 nm,respectively.The catalyst showed excellent activity in some important organic reactions including Biginelli,Hantzsch,Mannich,and Claisen-Schmidt reactions with good reusability.Catalytic activity of this nano catalyst is an improvement over the commercially available silica that is used to support H3PW12O40.

  20. Physicochemical and microbiological characterization of chicha, a rice-based fermented beverage produced by Umutina Brazilian Amerindians.

    Science.gov (United States)

    Puerari, Cláudia; Magalhães-Guedes, Karina Teixeira; Schwan, Rosane Freitas

    2015-04-01

    Chicha is a traditional, fermented rice beverage produced by the indigenous Umutina people in Brazil. Culture-dependent and independent approaches were used to investigate the microbial community dynamic. The bacterial population ranged from 0.1 to 6.83 log mL(-1). Lactic acid bacteria (LAB) and Bacillus dominated throughout the fermentation process. Representative colonies were grouped by Repetitive Extragenic Palindromic and Polymerase Chain Reaction (Rep-PCR) and by biochemical features. Genera of Lactobacillus, Bacillus, Leuconostoc, Enterococcus, Streptomyces, Enterobacter, Acinetobacter, Escherichia, Cronobacter, and Klebsiella were identified by partial 16S rRNA gene sequence. As shown by Polimerase and Denaturing Gradient Gel Electrophoresis (PCR-DGGE) analysis, uncultivable Bifidobacterium and Propioniobacterium were found throughout fermentation. Uncultured fungi composed the fungal PCR-DGGE profile. The pH values decreased from 5.2 (time 0) to 3.9 at 36 h of fermentation. Ethanol was not found. The lactic acid concentration increased rapidly throughout fermentation until it reached a high final value (1.4 g L(-1)) and the average glycerol content in the beverage was 0.425 g L(-1). Chicha fermentation might be described by the following phenomena: (i) increasing bacterial population, with lactic acid bacteria (LAB) as the largest group detected; (ii) increasing concentrations of lactic and citric acids; and (iii) the final product is characterized by a high content of acids and the absence of ethanol, therefore characterizing rice chicha an acidic and nonalcoholic beverage. First, this study characterizes the microbial population involved in the nonalcoholic fermentation of chicha, which is produced from rice by Amerindians in Brazil. This study is important for promoting the appreciation of and safeguarding this Brazilian indigenous beverage as an immaterial cultural heritage. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Ceria and titania incorporated silica based catalyst prepared from rice husk: adsorption and photocatalytic studies of methylene blue.

    Science.gov (United States)

    Adam, Farook; Muniandy, Lingeswarran; Thankappan, Radhika

    2013-09-15

    Titania and ceria incorporated rice husk silica based catalyst was synthesized via sol-gel method using CTAB and glycerol as surface directing agents at room temperature and labeled as RHS-50Ti10Ce. The catalyst was used to study the adsorption and photodegradation of methylene blue (MB) under UV irradiation. The powder XRD pattern of RHS-50Ti10Ce was much broader (2θ=25-30°) than that of the parent RHS (2θ=22°). The catalyst exhibited type IV isotherm with H3 hysteresis loop, and the TEM images showed partially ordered pore arrangements. The TGA-DTG thermograms confirmed the complete removal of the templates after calcination at 500°C. RHS-50Ti10Ce exhibited excellent adsorption capability with more than 99% removal of MB from a 40 mg L(-1) solution in just 15 min. It also decolorized an 80 mg L(-1) MB solution under UV irradiation in 210 min, which was comparable with the commercialized pure anatase TiO2. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Preparation of TiO2/MCM-41 photocatalyst using rice husk ash as silica source

    Science.gov (United States)

    Fatimah, Is; Sopia, Lusi

    2017-03-01

    This work aimed to prepare TiO2/MCM-41 from rice husk ash (RHA) agricultural waste and its application as photocatalyst in dye degradation. The preparation was conducted by two main steps; preparation of MCM-41 and titanium immobilization onto MCM-41. Sol gel method using CTMABr as templating agent was applied in MCM-41 synthesis and as TiO2 precursor, titanium isopropoxide was utilized. The study of physicochemical character change was performed by by X-ray diffraction, IR spectroscopy, BET method and thermogravimetric analysis (TGA). Photocatalytic activity of material was tested in methylene blue photodegradation system. According to the results, it is found that TiO2/MCM-41 has been successfully prepared and shows photocatalytic activity. Kinetic study of the reaction is discussed in this paper.

  3. Crystallization kinetic study of the lithium-disilicate bioceramic obtained from rice-husk silica starting powder; Estudo cinetico da cristalizacao da bioceramica de dissilicato de litio obtida atraves da silica da casca de arroz

    Energy Technology Data Exchange (ETDEWEB)

    Santos, F.A.; Santos, C.; Pinatti, D.G., E-mail: elipeantunes@usp.br [Universidade de Sao Paulo (EEL/USP), Lorena, SP (Brazil). Escola de Engenharia; Lazar, D.R.R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Davim, E.; Fernandes, M.H.F.V. [Universidade de Aveiro, Campos Universitario de Santiago, Aveiro (Portugal)

    2011-07-01

    In this work, the study of crystallization of the lithium disilicate glass-ceramic produced for alternative source (rice husk silica), and comparatively by commercial source (commercial silica) it was carried through. The stoichiometry 66%.mol SiO{sub 2}: 33%.mol LiO{sub 2} was used. The kinetic studies of crystallization and calculations had been carried through thermal analysis (DTA), and were possible to study the behavior of the curves in accordance with the variation of taxes (5; 10; 15; e 20°C/min), of the granulometries 63 μm, 250μm and 1mm), and for the influence of the substitution commercial SiO{sub 2} by rice husk. The structural characterization was carried through by X-Ray diffractometry (DRX) and scanning electron microscopy (MEV), for chemical characterization used X-Ray fluorescence (FRX). The preliminary results show that the substitution of the silica source is sufficiently promising, since the gotten properties are similar. (author)

  4. DNA tagging of blast resistant gene(s in three Brazilian rice cultivars

    Directory of Open Access Journals (Sweden)

    S.S. Sandhu

    2003-12-01

    Full Text Available Rice blast is the most important fungal disease of rice and is caused by Pyricularia oryzae Sacc. (Telomorph Magnoporthe grisea Barr.. Seven randomly amplified polymorphic DNA (RAPD markers OPA5, OPG17, OPG18, OPG19, OPF9, OPF17 and OPF19 showed very clear polymorphism in resistant cultivar lines which differed from susceptible lines. By comparing different susceptible lines, nine DNA amplifications of seven primers (OPA5(1000, OPA5(1200, OPG17(700, OPG18(850, OPG19(500, OPG19(600, OPF9(600, OPF17(1200 and OPF19(600 were identified as dominant markers for the blast resistant gene in resistant cultivar lines. These loci facilitate the indirect scoring of blast resistant and blast susceptible genotypes. The codomine RAPDs markers will facilitate marker-assisted selection of the blast resistant gene in two blast resistant genotypes of rice (Labelle and Line 11 and will be useful in rice breeding programs.

  5. Synthesis of biogenic silicon/silica (Si/SiO2) nanocomposites from rice husks and wheat bran through various microorganisms

    Science.gov (United States)

    Kaur, Taranjot; Pal Singh, Gurwinder; Kaur, Gurneet; Kaur, Sukhvir; Gill, Prabhjot Kaur

    2016-08-01

    Biosilification is an economically viable, energy saving and green approach for the commercial scale synthesis of oxide nanomaterials. The room temperature synthesis of oxide nanocomposites from cost effective agro-based waste is a particular example of biosilification. In this study, synthesis of Si/SiO2 nanocomposites from inexpensive agro-based waste material i.e. rice husks (RH) and wheat bran (WB) has been carried out by means of various eukaryotic microorganisms, i.e. Actinomycete, Fusarium oxysporum, Aspergillus niger, Trichoderma sp. and Penicillium sp., under ambient conditions. The XRD diffrectrograms represents that the synthesized nanomaterials exhibits silicon, amorphous silica and other crystal arrays such as cristobalite, trydimite and quartz, depending upon the type microorganism and time period used for extraction. All of the aforesaid microorganism bio transformed the naturally occurring amorphous silica to crystalline structures within the period of 24 h. However, the Actinomycete and Trichoderma sp. took 48 h in case of rice husks for biotransformation of naturally occurring plant silica to crystalline nanocomposite. While in case of wheat bran, Actinomycete and Trichoderma sp. took 24 h for biotransformation. The extracted nanocomposites exhibits band edge in the range 230-250 nm and blue emission. The procedure described in study can be used for commercial level production of Si/SiO2 nanocomposites from agro based waste materials.

  6. A Comparative Evaluation of Dried Activated Sludge and Mixed Dried Activated Sudge with Rice Husk silica to Remove Hydrogen Sulfide

    Directory of Open Access Journals (Sweden)

    Seyed Mahmoud Mehdinia

    2013-03-01

    Full Text Available The aim of this study was to investigate the effectiveness of dried activated sludge (DAS and mixed dried activated sludge with rice husk silica (DAS & RHS for removal of hydrogen sulfide (H2S. Two laboratory-scale filter columns (packed one litter were operated. Both systems were operated under different conditions of two parameters, namely different inlet gas concentrations and different inlet flow rates. The DAS & RHS packed filter showed more than 99.96% removal efficiency (RE with empty bed residence time (EBRT of 45 to 90 s and 300 mg/L inlet concentration of H2S. However, the RE decreased to 96.87% with the EBRT of 30 s. In the same condition, the DAS packed filter showed 99.37% RE. Nonetheless, the RE was shown to have dropped to 82.09% with the EBRT of 30 s. The maximum elimination capacity (EC was obtained in the DAS & RHS packed filter up to 52.32 g/m3h, with the RE of 96.87% and H2S mass loading rate of 54 g/m3h. The maximum EC in the DAS packed filter was obtained up to 44.33 g/m3h with the RE of 82.09% and the H2S mass loading rate of 54 g/m3h. After 53 days of operating time and 54 g/m3h of loading rates, the maximum pressure drop reached to 3.0 and 8.0 (mm H2O for the DAS & RHS packed and DAS packed filters, respectively. Based on the findings of this study, the DAS & RHS could be considered as a more suitable packing material to remove H2S.

  7. Performance at high temperature of alkali-activated slag pastes produced with silica fume and rice husk ash based activators

    Directory of Open Access Journals (Sweden)

    Bernal, S. A.

    2015-06-01

    Full Text Available This study assessed the mechanical properties, and structural changes induced by high temperature exposure, of alkali-silicate activated slag cements produced with sodium silicates derived from silica fume (SF and rice husk ash (RHA. Similar reaction products were identified, independent of the type of silicate used, but with subtle differences in the composition of the C-S-H gels, leading to different strength losses after elevated temperature exposure. Cements produced with the alternative activators developed higher compressive strengths than those produced with commercial silicate. All samples retained strengths of more than 50 MPa after exposure to 600 °C, however, after exposure to 800 °C only the specimens produced with the RHA-based activator retained measurable strength. This study elucidated that silicate-activated slag binders, either activated with commercial silicate solutions or with sodium silicates based on SF or RHA, are stable up to 600 °C.Este estudio evaluó las propiedades mecánicas, y cambios estructurales inducidos por exposición a temperaturas elevadas, de cementos de escoria activada alcalinamente producidos con silicatos sódicos derivados de humo de sílice (SF y ceniza de cascarilla de arroz (RHA. Se identificaron productos de reacción similares, independiente del tipo de silicato utilizado, pero con diferencias menores en la composición de las geles C-S-H, lo cual indujo diferentes pérdidas de resistencia posterior a exposición a temperaturas elevadas. Los cementantes producidos con los activadores alternativos desarrollaron resistencias a la compresión más altas que aquellos producidos con silicato comercial. Todas las muestras retuvieron resistencias de más de 50 MPa posterior a la exposición a 600 °C, sin embargo, posterior a la exposición a 800 °C únicamente muestras producidas con activadores de RHA retuvieron resistencias medibles. Este estudio elucidó que cementantes de escoria activada con

  8. Adsorption of Pb(II) using silica gel composite from rice husk ash modified 3-aminopropyltriethoxysilane (APTES)-activated carbon from coconut shell

    Science.gov (United States)

    Yusmaniar, Purwanto, Agung; Putri, Elfriyana Awalita; Rosyidah, Dzakiyyatur

    2017-03-01

    Silica gel modified by 3-aminopropyltriethoxysilane (APTES) was synthesized from rice husk ash combined with activated carbon from coconut shell yielded the composite adsorbent. The composite was characterized by Fourier Transform Infra Red spectroscopy (FT-IR), Electron Dispersive X-Ray (EDX), Surface Area Analyzer (SAA) and adsorption test by Atomic Absorption Spectrometry (AAS). This composite adsorbent has been used moderately for the removal of lead ions from metal solutions and compared with silica gel modified APTES and activated carbon. The adsorption experiments of Pb -ions by adsorbents were performed at different pH and contact time with the same metal solutions concentration, volume solution, and adsorbent dosage. The optimum pH for the adsorption was found to be 5.0 and the equilibrium was achieved for Pb with 20 min of contact time. Pb ions adsorption by composite silica gel modified APTES-activated carbon followed by Langmuir isotherm model with qmax value of 46.9483 mg/g that proved an adsorbent mechanism consistent to the mechanism of monolayer formation.

  9. High-throughput transformation pipeline for a Brazilian japonica rice with bar gene selection.

    Science.gov (United States)

    Dedicova, B; Bermudez, C; Prias, M; Zuniga, E; Brondani, C

    2015-07-01

    The goal of this work was to establish a transformation pipeline for upland Curinga rice (Oryza sativa L. ssp. japonica) with bar gene selection employing bialaphos and phosphinothricin as selection agents. The following genes of interest: AtNCED3, Lsi1, GLU2, LEW2, PLD-alpha, DA1, TOR, AVP1, and Rubisco were cloned into the binary vector p7i2x-Ubi and were transferred into Agrobacterium strain EHA 105. Embryogenic calli derived from the mature embryos were transformed, and transgenic cells and shoots were selected on the medium supplemented with bialaphos or phosphinothricin (PPT) using a stepwise selection scheme. Molecular analyses were established using polymerase chain reaction and Southern blot for the bar gene and the NOS terminator. Overall, 273 putative transgenic plants were analyzed by Southern blot with 134 events identified. In total, 77 events had a single copy of the transgene integrated in the plant genome while 29 events had two copies. We tested backbone integration in 101 transgenic plants from all constructs and found 60 transgenic plants having no additional sequence integrated in the plant genome. The bar gene activity was evaluated by the chlorophenol red test and the leaf painting test using phosphinothricin with several transgenic plants. The majority of T0 plants carrying the single copy of transgene produced T1 seeds in the screen house.

  10. Effect of sintering temperature on mechanical behaviour and bioactivity of sol-gel synthesized bioglass-ceramics using rice husk ash as a silica source

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, J.P., E-mail: jyotiprakash_nitrkl@rediffmail.com [Department of Ceramic Engineering, National Institute of Technology, Rourkela, Odisha 769008 (India); Bera, J., E-mail: bera@rediffmail.com [Department of Ceramic Engineering, National Institute of Technology, Rourkela, Odisha 769008 (India)

    2010-11-01

    Bioglass-ceramics with SiO{sub 2}-Na{sub 2}O-CaO composition was prepared by sol-gel method using rice husk ash as a silica source. Material was sintered at different temperatures ranging from 900 to 1050 deg. C for 2 h. Phase-formation behaviour, densification characteristics, and mechanical strength of glass-ceramics were investigated. The material sintered at 1000 deg. C showed a good mechanical strength. Mechanical properties were correlated with microstructural features. Both in vitro bioactivity and biodegradability of sintered material were investigated by incubating in simulated body fluid and Tris buffer solution, respectively. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction were used to investigate the surface deposition during body fluid incubation. Both bioactivity and degradability decreased with increase in sintering temperature.

  11. Effect of sintering temperature on mechanical behaviour and bioactivity of sol-gel synthesized bioglass-ceramics using rice husk ash as a silica source

    Science.gov (United States)

    Nayak, J. P.; Bera, J.

    2010-11-01

    Bioglass-ceramics with SiO2-Na2O-CaO composition was prepared by sol-gel method using rice husk ash as a silica source. Material was sintered at different temperatures ranging from 900 to 1050 °C for 2 h. Phase-formation behaviour, densification characteristics, and mechanical strength of glass-ceramics were investigated. The material sintered at 1000 °C showed a good mechanical strength. Mechanical properties were correlated with microstructural features. Both in vitro bioactivity and biodegradability of sintered material were investigated by incubating in simulated body fluid and Tris buffer solution, respectively. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction were used to investigate the surface deposition during body fluid incubation. Both bioactivity and degradability decreased with increase in sintering temperature.

  12. Rice husks as a sustainable silica source for hierarchical flower-like metal silicate architectures assembled into ultrathin nanosheets for adsorption and catalysis.

    Science.gov (United States)

    Zhang, Shouwei; Gao, Huihui; Li, Jiaxing; Huang, Yongshun; Alsaedi, Ahmed; Hayat, Tasawar; Xu, Xijin; Wang, Xiangke

    2017-01-05

    Metal silicates have attracted extensive interests due to their unique structure and promising properties in adsorption and catalysis. However, their applications were hampered by the complex and expensive synthesis. In this paper, three-dimensional (3D) hierarchical flower-like metal silicate, including magnesium silicate, zinc silicate, nickel silicate and cobalt silicate, were for the first time prepared by using rice husks as a sustainable silicon source. The flower-like morphology, interconnected ultrathin nanosheets structure and high specific surface area endowed them with versatile applications. Magnesium silicate was used as an adsorbent with the maximum adsorption capacities of 557.9, 381.3, and 482.8mg/g for Pb2+, tetracycline (TC), and UO22+, respectively. Ni nanoparticles/silica (Ni NPs/SiO2) exhibited high catalytic activity and good stability for 4-nitrophenol (4-NP) reduction within only ∼160s, which can be attributed to the ultra-small particle size (∼6.8nm), good dispersion and high loading capacity of Ni NPs. Considering the abundance and renewability of rice husks, metal silicate with complex architecture can be easily produced at a large scale and become a sustainable and reliable resource for multifunctional applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Adsorption of Ca(II, Mg(II, Zn(II, and Cd(II on Chitosan Membrane Blended with Rice Hull Ash Silica and Polyethylene Glycol

    Directory of Open Access Journals (Sweden)

    F. Widhi Mahatmanti

    2016-03-01

    Full Text Available In this research, chitosan based membrane blended with rice hull ash (RHA silica and polyethylene glycol (PEG has been applied as adsorbent of Ca(II, Mg(II, Zn(II and Cd(II in an aqueous solution. Membrane was synthesized by blending RHA silica and polyethylene glycol into chitosan. Silica and polyethylene glycol blended into the chitosan to improve the mechanical properties and the membrane porous. The membrane was characterized using Fourier Transform infrared (FTIR spectroscopy, X-Ray Diffraction (XRD, Scanning Electron Microscopy (SEM, and swelling degree analyzer. Adsorption of metal ions investigated was conducted in a batch system with variation of pH, initial ion concentration and contact time. Thermodynamics and kinetics of adsorption were evaluated based on the adsorption data at initial metal ion concentration and contact time variations, respectively. Results showed that the optimum condition of adsorption was at pH 9.0 for Ca(II, 6.0 for both Mg(II and Zn(II and 5.5 for Cd(II, and contact time of 24 h for all ions investigated. Kinetics of all investigated metal ion adsorption followed a kinetic model of pseudo-second-order. Adsorption of Ca(II and Mg(II on the membrane fitted to Freundlich model with the affinity of 1.266 and 1.099, respectively; and Zn(II and Cd(II fitted to Langmuir one with the capacity of 182 and 106 µmol/g, respectively.

  14. Effect of sintering temperature variations on fabrication of 45S5 bioactive glass-ceramics using rice husk as a source for silica.

    Science.gov (United States)

    Leenakul, Wilaiwan; Tunkasiri, Tawee; Tongsiri, Natee; Pengpat, Kamonpan; Ruangsuriya, Jetsada

    2016-04-01

    45S5 bioactive glass is a highly bioactive substance that has the ability to promote stem cell differentiation into osteoblasts--the cells that create bone matrix. The aim of this work is to analyze physical and mechanical properties of 45S5 bioactive glass fabricated by using rice husk ash as its silica source. The 45S5 bioactive glass was prepared by melting the batch at 1300 °C for 3h. The samples were sintered at different temperatures ranging from 900 to 1050 °C with a fixed dwell-time of 2h. The phase transitions, density, porosity and microhardness values were investigated and reported. DTA analysis was used to examine the crystallization temperatures of the glasses prepared. We found that the sintering temperature had a significant effect on the mechanical and physical properties of the bioactive glass. The XRD showed that when the sintering temperature was above 650 °C, crystallization occurred and bioactive glass-ceramics with Na2Ca2Si3O9, Na2Ca4(PO4)2SiO4 and Ca3Si2O7 were formed. The optimum sintering temperature resulting in maximum mechanical values was around 1050 °C, with a high density of 2.27 g/cm(3), 16.96% porosity and the vicker microhardness value of 364HV. Additionally, in vitro assay was used to examine biological activities in stimulated body fluid (SBF). After incubation in SBF for 7 days, all of the samples showed formations of apatite layers indicating that the 45S5 bioactive glasses using rice husk as a raw material were also bioactive. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Caracterização de cinza de casca de arroz para uso como matéria-prima na fabricação de refratários de sílica Characterization of rice husk ash for use as raw material in the manufacture of silica refractory

    Directory of Open Access Journals (Sweden)

    Viviana Possamai Della

    2001-12-01

    Full Text Available The characterization of rice husk ash, a deriving by-product of the burning of the rice husk during the rice processing is the object of this study. This by-product, for being rich in silica, can be an important raw material for the production of siliceous ceramics, such as thermal insulators and refractory. A combination of surface analysis, thermal analysis and microscopy analysis techniques was used for the characterization. The characterized by-product presented as main component the silica, under amorphous form, with a maximum content of alkalis around 1%, features that become it potentially interesting for the production of ceramic materials.

  16. ENCAPSULATION OF HORSERADISH PEROXIDASE-GLUCOSE OXIDASE (HRP-GOx IN SILICA AQUAGEL SYNTHESIZED FROM RICE HULL ASH FOR ENZYMATIC REACTION OF GLUCOSE

    Directory of Open Access Journals (Sweden)

    Nuryono Nuryono

    2010-06-01

    Full Text Available In recent years, the sol-gel technique has attracted increasing interest as a unique approach to immobilize biomolecules for bioanalytical applications as well as biochemical and biophysical studies. In this research, encapsulation of Horseradish peroxidase-Glucose oxidase (HRP-GOx enzymes in silica aquagel from rice hull ash by sol-gel process has been carried out. In addition, the effect of several parameters (weight ratio of HRP to GOx, pH, temperature, sodium ion concentration on enzyme activity was studied, as well. Rice hull ash, which was produced by ashing at 700 °C, was extracted it's silika by NaOH solution 1 M at 100 °C for two hours to produce sodium silikate (Na2SiO3 solution. The Na2SiO3 solution with pH of 13 was added with a strong cation exchanger resin, to produce sol solution with the pH of 4. Encapsulation was emphasized by mixing sol solution and phosphate buffer pH 7 containing HRP-GOx solution at volume ratio of buffer to sol solution 1:5. The mixture was transferred into 96-microwell plate and was aged for 24 hours. Enzymatic reaction was carried out by adding chromogenic solution of phenol and 4-aminoantipyrine (4-AAP and b-D-glucose solution (as substrate into the microwell. Enzymatic activity was examined by measuring absorbance of product solution at 490 nm with ELISA reader. Result of enzymatic activity for encapsulated enzymes (SGE was compared to that for free enzymes (EB. Results showed that at the investigated condition, HRP-GOx enzymes gave high activity at weight ratio of HRP to GOx 10:1 and pH 7 for both SGE and EB. Encapsulation caused the enzymes activity decrease to 53.0±0.2 %. However, SGE was observed to be more stable on pH and temperature changes than EB. Study on the effect of sodium concentration showed that the increase of sodium concentration from 0.10 to 0.37 M decreased the enzymatic activity to 56±0.2%. Reusability test showed that the synthesized SGE was reusable with activity decrease of 60

  17. ADSORPTION OF Ca(II, Pb(II AND Ag(I ON SULFONATO-SILICA HYBRID PREPARED FROM RICE HULL ASH

    Directory of Open Access Journals (Sweden)

    Siti Sulastri

    2011-12-01

    Full Text Available In this research, adsorption of Ca(II, Pb(II and Ag(I in aqueous solution onto sulfonato-silica hybrid (SSH prepared from rice hull ash (RHA has been studied. The preparation of SSH adsorbent was carried out by oxidation of mercapto-silica hybrid (MSH with hydrogen peroxide (H2O2 solution 33%. MSH was prepared, via sol-gel process, by adding 3 M hydrochloric acid solution to mixture of sodium silicate (Na2SiO3 solution and 3(trimethoxysilyl-1-propanthiol (MPTS to reach pH of 7.0. Solution of Na2SiO3 was generated from destruction of RHA with sodium hydroxide solution followed with heating at 500 °C for 30 min. The SSH produced was characterized with Fourier transform infrared (FTIR spectroscopy, X-ray diffraction (XRD analyzer, energy dispersive X-ray (EDX spectroscopy and determination of ion-exchange capacity for sodium ion (Na+. The adsorption of Ag(I and Ca(II were conducted in a batch system in various concentrations for one hour. The adsorbent ion was calculated based on difference of concentrations before and after adsorption process determined using atomic absorbance spectrophotometric (AAS method. The adsorption character was evaluated using model of isotherm Langmuir and Freundlich adsorption to calculate the capacity, constants and energy of adsorption. Result of characterization by EDX and FTIR showed qualitatively that SSH has been successfully synthesized which were indicated by appearance of characteristic absorbance of functional group namely silanol (Si-OH, siloxane (Si-O-Si, methylene (-CH2- and disappearance of mercapto group (SH. The XRD data showed amorphous structure of SSH, similar to silica gel (SG and MSH. The study of adsorption thermodynamics showed that oxidation of MSH into SSH increases the ion-exchange capacity for Na+ from 0.123 to 0.575 mmol/g. The change in functional group from silanol to mercapto and from mercapto to sulfonato increases the adsorption capacity of Ca(II. However, the capacity order of

  18. THE USE OF THE RIETVELD METHOD TO STUDY THE PHASE COMPOSITION OF CORDIERITE (Mg2Al4Si5O18 CERAMICS PREPARED FROM RICE HUSK SILICA

    Directory of Open Access Journals (Sweden)

    Simon Sembiring

    2011-04-01

    Full Text Available This research presents the use of the Rietveld method to study the phase composition of cordierite (MG2AL4SI5O18 ceramics prepared from rice husk silica, after the samples were sintered at 1300, 1400 and 1500 °C. The formation of cordierite is temperature-dependent as indicated by the relative phase composition obtained from x-ray diffraction patterns for the cordierite and spinel increased markedly with increasing temperature, i.e, from 38.98 to 54.15 wt% and from 11.81 to 17.99 wt % following the increase in temperature from 1300-1500 °C, respectively. The above values were obtained with the aid of the Rietveld method, carried out until the goodness of fit values (GoF reached below 2, which is considered a satisfactory value to reveal the real phase composition. Different plots produced by refinement using the Rietveld method also reveal a reasonable fit between the observed and the calculated plot, demonstrating the usefulness of the method for calculating the quantity of phase composition in the sintering process

  19. Trace gas fluxes from intensively managed rice and soybean fields across three growing seasons in the Brazilian Amazon

    Science.gov (United States)

    R.C. Oliveira Junior; Michael Keller; P. Crill; T. Beldini; J. Van Haren; P. Camargo

    2015-01-01

    The emission of gases that may potentially intensify the greenhouse effect has received special attention due to their ability to raise global temperatures and possibly modify conditions for life on earth. The objectives of this study were the quantification of trace gas flux (N2O, CO2 and CH4) in soils of the lower Amazon basin that are planted with rice and soybean,...

  20. Diversity of bacteria and yeast in the naturally fermented cotton seed and rice beverage produced by Brazilian Amerindians.

    Science.gov (United States)

    Ramos, Cíntia Lacerda; de Almeida, Euziclei Gonzaga; Freire, Ana Luiza; Freitas Schwan, Rosane

    2011-10-01

    Microorganisms associated with the fermentation of cotton seed and rice were studied using a combination of culture-dependent and -independent methods. Samples of the cotton seed and rice beverage were collected every 8 h during the fermentation process for analysis of the microbiota present over 48 h. The lactic acid bacteria (LAB) population reached values of approximately 8.0 log cfu/mL. A total of 162 bacteria and 81 yeast isolates were identified using polyphasic methods. LAB (Lactobacillus plantarum, Lactobacillus vermiforme, Lactobacillus paracasei) were the most frequently isolated bacteria. Bacillus subtilis was present from 16 h until the end of the fermentation process. A decrease in pH value from 6.92 (0 h) to 4.76 (48 h) was observed, and the concentration of lactic acid reached 24 g/L at the end of the fermentation process. DGGE (denaturing gradient gel electrophoresis) was performed to determine the dynamics of the communities of bacteria and yeast, and the analysis revealed a predominance of LAB throughout the fermentation process. No changes were observed in the yeast community. The yeast species detected were Candida parapsilosis, Candida orthopsilosis, Clavispora lusitaniae and Rhodotorula mucilaginosa. Our studies indicate that the DGGE technique combined with a culture-dependent method is required to discern the dynamics in the fermentation of cotton seed and rice. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. removal of heavy metal ions from aqueous solution using rice husks ...

    African Journals Online (AJOL)

    User

    ABSTRACT. This study reports on the preparation and characterization of rice husks-based adsorbents and their application in the removal of heavy metal ions from aqueous solution. Three different adsorbents were developed: rice husks ash (RHA), rice husks ash-derived silica (RHS) and triaminopropyl-silica hybrid ...

  2. Silica deposition and rate the nitrogen is silicon in riceDeposição de sílica e teor de nitrogênio e silício em arroz

    Directory of Open Access Journals (Sweden)

    Munir Mauad

    2013-09-01

    Full Text Available The nitrogen fertilization is an important practice to reach high productivity, however, nitrogen high level can cause lodging and make the plants more sensitive to disease. Numerous studies has demonstrate that a lot of grasses accumulate silicon at its tissues, and the biggest part of this element is deposited on the leaf, that would work like a mechanical barrier to diseases come in. However, high levels of nitrogen can reduce the silica deposition at the plants. The objective of this study was to evaluate silicon and nitrogen content in shoot and silica deposition in upland rice leaf as a result of Si and N levels. The experimental design used was completely randomized in factorial schema 3 x 2 with five replications. The treatments consisted from levels of N (5, 75 and 150 mg dm-3 of soil in urea form and two levels of SiO2 (0 e 400 mg dm-3 in calcium silicate form (Wollastonita. The increased of urea fertilization reduced the silicon content of rice plants and the silica deposition at the external cells wall the epidermal rice leafs. A adubação nitrogenada é pratica importante para alcançar altas produtividades, entretanto doses elevadas de nitrogênio podem causar tombamento e tornar as plantas mais suscetíveis a doenças. Numerosos estudos têm demonstrado que muitas gramíneas acumulam silício em seus tecidos, e que a maior parte deste elemento é depositado na folha, o que funcionária como uma barreira mecânica a entrada de doenças. Entretanto elevadas doses de nitrogênio podem diminuir a deposição de sílica nas plantas. O objetivo deste trabalho foi avaliar o teor de nitrogênio e silício na parte aérea, e a deposição de sílica em folhas de plantas de arroz de terras altas em função das doses de Si e N. O delineamento experimental utilizado foi inteiramente casualizado, em esquema fatorial 3 x 2, com cinco repetições. Os tratamentos foram constituídos por três doses de N (5, 75 e 150 mg dm-3 de N tendo como

  3. Obtenção de mulita porosa a partir da sílica da casca de arroz e do acetato de alumínio Porous mullite obtained using silica from rice husk and aluminum acetate

    Directory of Open Access Journals (Sweden)

    R. R. Menezes

    2008-06-01

    Full Text Available O grande volume de produção de arroz no mundo gera uma enorme quantidade de rejeito na forma de cascas e de cinzas oriundas da queima da casca. Esses resíduos são fontes de poluição e contaminação, podendo agredir diretamente a saúde da população. Assim, esse trabalho tem por objetivo a obtenção de mulita porosa a partir da sílica da casca de arroz e do acetato de alumínio. O resíduo foi física e quimicamente caracterizado e em seguida misturado com acetato de alumínio para a produção do precursor da mulita. O material precursor foi caracterizado termicamente e com base nos resultados foi calcinado a 850 ºC e 1200 ºC. Os corpos de prova foram queimados a 1500 ºC e 1600 ºC e caracterizados pela determinação de sua porosidade aparente, absorção de água e densidade aparente e por difração de raios X e microscopia eletrônica de varredura. Os resultados indicaram que a sílica é constituída por material amorfo e aglomerados micrométricos de partículas submicrométricas e nanométricas. Com base nos resultados conclui-se que a sílica obtida da casca de arroz e o acetato de alumínio podem ser utilizados com sucesso para a produção de corpos mulíticos porosos com porosidades superiores a 48%.The production of rice around the world generates large amounts of waste in the form of husks and ashes from husks burning, which are sources of environmental contamination and pollution. The aim of this work was obtain porous mullite bodies using the silica from the rice husk and aluminum acetate. The waste material was physically and chemically characterized. The mullite precursor was produced mixing the waste and aluminum acetate. The thermal behavior of mullite precursor was described. The precursor was fired at 850 ºC and 1200 ºC and sample bodies were sintered at 1500 and 1600 ºC. Sintered samples were characterized to determine their apparent porosity, water absorption, apparent density, and microstructurally

  4. influence of addition of rice husk ash on porcelain composition

    African Journals Online (AJOL)

    ABSTRACT. Rice husk ash (RHA) has long been known to possess high silica content. The abundance of rice husk as agricultural waste makes it the most promising to be used as a supplementary cementations and ceramic material. In this study RHA was used as an additive material on porcelain body. The rice husk was ...

  5. Influence of Addition of Rice Husk Ash on Porcelain Composition ...

    African Journals Online (AJOL)

    Rice husk ash (RHA) has long been known to possess high silica content. The abundance of rice husk as agricultural waste makes it the most promising to be used as a supplementary cementations and ceramic material. In this study RHA was used as an additive material on porcelain body. The rice husk was subjected to ...

  6. Recycling rice husks for high-capacity lithium battery anodes.

    Science.gov (United States)

    Jung, Dae Soo; Ryou, Myung-Hyun; Sung, Yong Joo; Park, Seung Bin; Choi, Jang Wook

    2013-07-23

    The rice husk is the outer covering of a rice kernel and protects the inner ingredients from external attack by insects and bacteria. To perform this function while ventilating air and moisture, rice plants have developed unique nanoporous silica layers in their husks through years of natural evolution. Despite the massive amount of annual production near 10(8) tons worldwide, so far rice husks have been recycled only for low-value agricultural items. In an effort to recycle rice husks for high-value applications, we convert the silica to silicon and use it for high-capacity lithium battery anodes. Taking advantage of the interconnected nanoporous structure naturally existing in rice husks, the converted silicon exhibits excellent electrochemical performance as a lithium battery anode, suggesting that rice husks can be a massive resource for use in high-capacity lithium battery negative electrodes.

  7. Silica Nephropathy

    Directory of Open Access Journals (Sweden)

    N Ghahramani

    2010-06-01

    Full Text Available Occupational exposure to heavy metals, organic solvents and silica is associated with a variety of renal manifestations. Improved understanding of occupational renal disease provides insight into environmental renal disease, improving knowledge of disease pathogenesis. Silica (SiO2 is an abundant mineral found in sand, rock, and soil. Workers exposed to silica include sandblasters, miners, quarry workers, masons, ceramic workers and glass manufacturers. New cases of silicosis per year have been estimated in the US to be 3600–7300. Exposure to silica has been associated with tubulointerstitial disease, immune-mediated multisystem disease, chronic kidney disease and end-stage renal disease. A rare syndrome of painful, nodular skin lesions has been described in dialysis patients with excessive levels of silicon. Balkan endemic nephropathy is postulated to be due to chronic intoxication with drinking water polluted by silicates released during soil erosion. The mechanism of silica nephrotoxicity is thought to be through direct nephrotoxicity, as well as silica-induced autoimmune diseases such as scleroderma and systemic lupus erythematosus. The renal histopathology varies from focal to crescentic and necrotizing glomerulonephritis with aneurysm formation suggestive of polyarteritis nodosa. The treatment for silica nephrotoxicity is non-specific and depends on the mechanism and stage of the disease. It is quite clear that further research is needed, particularly to elucidate the pathogenesis of silica nephropathy. Considering the importance of diagnosing exposure-related renal disease at early stages, it is imperative to obtain a thorough occupational history in all patients with renal disease, with particular emphasis on exposure to silica, heavy metals, and solvents.

  8. Species diversity, pathogenicity and toxigenicity of Fusarium associated with rice seeds in Brazil

    Science.gov (United States)

    Fusarium is commonly reported in association with rice seeds in Brazil, but knowledge on the species diversity and toxigenic potential is lacking. Such information is critical because maximum limits for Fusarium mycotoxins were set for Brazilian rice in 2011. Ninety-eight rice seed samples from the ...

  9. Palm Ash as an Alternative Source for Silica Production

    Directory of Open Access Journals (Sweden)

    Pa Faizul Che

    2016-01-01

    Full Text Available Agricultural wastes such as palm ash and rice husk have a possibility to be used as a useful renewable source for the production of silica (SiO2. Extensive researches have been carried out to extract silica from agricultural wastes such as rice husk, due to silica as a useful raw material for industrial application. In this study, the environmentally benign and economically effective process to produce SiO2 materials from palm ash has been established by using citric acid leaching, not the conventional strong acids. Results showed that silica can be extracted from palm ash using the citric acid leaching method under the optimum extracting conditions with 700 °C of solution temperature, 60 minutes of reaction time and concentration of citric acid of more than 2 %. The purity of silica extracted is more than 90 %.

  10. Using rice straw to manufacture ceramic bricks

    Directory of Open Access Journals (Sweden)

    Gorbunov German Ivanovich

    2014-12-01

    Full Text Available In the article, the co-authors offer their advanced and efficient methodologies for the recycling of the rice straw, as well as the novel approaches to the ceramic brick quality improvement through the application of the rice straw as the combustible additive and through the formation of amorphous silica in the course of the rice straw combustion. The co-authors provide characteristics of the raw materials, production techniques used to manufacture ceramic bricks, and their basic properties in the article. The co-authors describe the simulated process of formation of amorphous silica. The process in question has two independent steps (or options: 1 rice straw combustion and ash formation outside the oven (in the oxidizing medium, and further application of ash as the additive in the process of burning clay mixtures; 2 adding pre-treated rice straw as the combustible additive into the clay mixture, and its further burning in compliance with the pre-set temperature mode. The findings have proven that the most rational pre-requisite of the rice straw application in the manufacturing of ceramic bricks consists in feeding milled straw into the clay mixture to be followed by molding, drying and burning. Brick samples are highly porous, and they also demonstrate sufficient compressive strength. The co-authors have also identified optimal values of rice straw and ash content in the mixtures under research.

  11. Bioethanol production from rice straw: An overview.

    Science.gov (United States)

    Binod, Parameswaran; Sindhu, Raveendran; Singhania, Reeta Rani; Vikram, Surender; Devi, Lalitha; Nagalakshmi, Satya; Kurien, Noble; Sukumaran, Rajeev K; Pandey, Ashok

    2010-07-01

    Rice straw is an attractive lignocellulosic material for bioethanol production since it is one of the most abundant renewable resources. It has several characteristics, such as high cellulose and hemicelluloses content that can be readily hydrolyzed into fermentable sugars. But there occur several challenges and limitations in the process of converting rice straw to ethanol. The presence of high ash and silica content in rice straw makes it an inferior feedstock for ethanol production. One of the major challenges in developing technology for bioethanol production from rice straw is selection of an appropriate pretreatment technique. The choice of pretreatment methods plays an important role to increase the efficiency of enzymatic saccharification thereby making the whole process economically viable. The present review discusses the available technologies for bioethanol production using rice straw. Copyright 2009 Elsevier Ltd. All rights reserved.

  12. Rice Nutrition

    Science.gov (United States)

    This chapter presents the symptoms of deficiency and toxicity of the major and minor mineral nutrients in rice, as well as a current synopsis of nutrient transporters and their regulation. The availability of sequences from the recently completed rice genome has furthered the knowledge of how plants...

  13. Effect of Nano Silica on the Physical Property of Porous Concrete Pavement

    Science.gov (United States)

    Yusak, Mohd Ibrahim Mohd; Ezree Abdullah, Mohd; Putra Jaya, Ramadhansyah; Rosli Hainin, Mohd; Ibrahim, Mohd Haziman Wan

    2017-08-01

    Rice husk can be categorized as an organic waste material from paddy industries. Silica is a major inorganic element of the rice husk. The aim of present study is to evaluate the effect of Nano silica on the physical properties of porous concrete pavement. Rice husk has been burned in the furnace (650°C for 6 hours) and ground for four different grinding times (33, 48, 63 and 81 hours). Five types of mixes were prepared to evaluate the different Nano silica grinding time. A Nano silica dosage of 10% by weight of binder was used throughout the experiments. The physical properties were examined through compressive strength, transmission electron microscopy and x-ray fluorescence. The experimental results indicate that the different Nano size gives a different effect to porous concrete strength. Based on the results obtained, Nano silica ground for 63 hours (65.84nm) gives the best result and performance to porous concrete pavement specimens.

  14. Studies on development of new functional natural materials from agricultural products - Technology developments for ceramic powders and materials from rice phytoliths

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Dae Kap; Kim, Yong Ik [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Yoon, Nang Kyu; Seong, Seo Yong [Myongseong Ceramics Com., Taejon (Korea, Republic of); Ryu, Sang Eun [Bae Jae Univ., Taejon (Korea, Republic of); Lee, Jae Chun [Myungji Univ., Seoul (Korea, Republic of)

    1995-08-01

    Based on an estimation of annual rice production of 5.2 million tons, rice husks by-production reaches to 1.17 million tons per year in Korea. Distinguished to other corns, rice contains a lot of Si; 10-20% by weight in rice husks calculated as silica. The aim of this research project is to develop technologies for ceramic powders and materials utilizing the silica in rice husks called phytoliths. In this first year research, researches of the following subjects were performed; material properties of rice husks, milling of rice husks, acid treatments, oxidations at low and high temperatures, sintering and crystalization of amorphous silica, low temperature carburization, formation of silicon carbide whiskers, and brick lightening method using milled rice husks. 11 tabs., 49 figs., 75 refs. (Author).

  15. Antimicrobial Activity of UV-Induced Phenylamides from Rice Leaves

    Directory of Open Access Journals (Sweden)

    Hye Lin Park

    2014-11-01

    Full Text Available Rice produces a wide array of phytoalexins in response to pathogen attacks and UV-irradiation. Except for the flavonoid sakuranetin, most phytoalexins identified in rice are diterpenoid compounds. Analysis of phenolic-enriched fractions from UV-treated rice leaves showed that several phenolic compounds in addition to sakuranetin accumulated remarkably in rice leaves. We isolated two compounds from UV-treated rice leaves using silica gel column chromatography and preparative HPLC. The isolated phenolic compounds were identified as phenylamide compounds: N-trans-cinnamoyltryptamine and N-p-coumaroylserotonin. Expression analysis of biosynthetic genes demonstrated that genes for arylamine biosynthesis were upregulated by UV irradiation. This result suggested that phenylamide biosynthetic pathways are activated in rice leaves by UV treatment. To unravel the role of UV-induced phenylamides as phytoalexins, we examined their antimicrobial activity against rice fungal and bacterial pathogens. N-trans-Cinnamoyltryptamine inhibited the growth of rice brown spot fungus (Bipolaris oryzae. In addition to the known antifungal activity to the blast fungus, sakuranetin had antimicrobial activity toward B. oryzae and Rhizoctonia solani (rice sheath blight fungus. UV-induced phenylamides and sakuranetin also had antimicrobial activity against rice bacterial pathogens for grain rot (Burkholderia glumae, blight (Xanthomonas oryzae pv. oryzae and leaf streak (X. oryzae pv. oryzicola diseases. These findings suggested that the UV-induced phenylamides in rice are phytoalexins against a diverse array of pathogens.

  16. Study on the blackbird (Agelaius ruficapillus Viellot- Emberizidae, Aves) in the rice production areas of Southern Rio Grande do Sul, Brazil : basis for a population control management program

    NARCIS (Netherlands)

    Silva, da J.J.C.

    1999-01-01

    Rice is one of the main components of the Brazilian diet. The State of Rio Grande do Sul produces approximately 4,6 millions tons per year - more than 54% of total Brazilian rice production. The average production in Southern Brazil is 5,2 tons per ha, with yields of 10 tons per ha being

  17. Potassium hydroxide pulping of rice straw in biorefinery initiatives.

    Science.gov (United States)

    Jahan, M Sarwar; Haris, Fahmida; Rahman, M Mostafizur; Samaddar, Purabi Rani; Sutradhar, Shrikanta

    2016-11-01

    Rice straw is supposed to be one of the most important lignocellulosic raw materials for pulp mill in Asian countries. The major problem in rice straw pulping is silica. The present research is focused on the separation of silica from the black liquor of rice straw pulping by potassium hydroxide (KOH) and pulp evaluation. Optimum KOH pulping conditions of rice straw were alkali charge 12% as NaOH, cooking temperature 150°C for 2h and material to liquor ratio, 1:6. At this condition pulp yield was 42.4% with kappa number 10.3. KOH pulp bleached to 85% brightness by D0EpD1 bleaching sequences with ClO2 consumption of 25kg/ton of pulp. Silica and lignin were separated from the black liquor of KOH pulping. The amount of recovered silica, lignin and hemicelluloses were 10.4%, 8.4% and 13.0%. The papermaking properties of KOH pulp from rice straw were slightly better than those of corresponding NaOH pulp. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. the suitability of lime rice husk ash cement as construction material

    African Journals Online (AJOL)

    NIJOTECH

    potassium oxide and sodium oxide in the Portland cement to the values found in the rice husk ash a new product, "Artificial Lime Rice ... successful reduction of the high percentage of silica, potassium oxide and sodium oxide to the level present in ordinary ..... cement shows a unique trend of strength increase with time and ...

  19. Microstructure and tensile properties of various varieties of rice husk.

    Science.gov (United States)

    Chen, Ziyong; Xu, Yangzi; Shivkumar, Satya

    2017-07-19

    Rice husk is a complex hierarchical assembly of hollow fibers consisting of cellulose, hemicellulose and lignin. In addition, it can also contain pectin and significant amounts of silica. Rice husk can be used in diverse applications and generally in the form of rice husk powder. This study aimed to investigate the structural features and mechanical properties of various varieties of whole rice husks. Rice husk consists of three sections: epidermis, sub-hypodermis and hypodermis. The thickness of these layers, the diameters of the hollow fibers and the wall thickness vary with the variety of rice husk. The elastic modulus is typically between 0.3 and 2.6 GPa, and the ultimate tensile strength varies from 19 to 135 MPa depending on the variety of rice husk. Rice husk has a unique hierarchical structure in which the fibers exhibit a staggered perpendicular arrangement and the entire fiber sections are covered by an external shell. The tensile properties vary with the variety of rice husk. The wide range in these tensile properties may be attributed to the size and orientation of the fibers. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  20. Production of micro- and nanosilica from soil inhabiting Folsomia candida fed with treated rice husk.

    Science.gov (United States)

    Moreno-Murguía, Barbara; Soto-Mercado, Jorge R; Morales-Malacara, Juan B; Castaño, Victor M

    2015-08-01

    Rice husk was employed as a source for producing silica micro- and nanoparticles through its digestion by soil fauna. Although many physicochemical methods for producing nanostructures have been studied, the biological processes remain mostly unexplored. Alkaline hydrogen peroxide with continuous control of reaction pH allowed removal of lignin bonds while preserving most of the cell wall and the silica present in the rice husk. The accessibility of lignocellulose was achieved without removing appreciable amounts of lignin, so this agricultural byproduct can be employed as feeding material for microarthropods Folsomia candida (Collembola). When these microarthropods are placed on a substrate of treated rice husk, more than 85% of degraded material is obtained, as compared to the untreated rice husk substrate, while the silica particles obtained show a slight decrease in average size.

  1. Comparison between rice husk ash grown in different regions for stabilizing fly ash from a solid waste incinerator.

    Science.gov (United States)

    Benassi, L; Bosio, A; Dalipi, R; Borgese, L; Rodella, N; Pasquali, M; Depero, L E; Bergese, P; Bontempi, E

    2015-08-15

    The Stabilization of heavy metals from municipal solid waste incineration (MSWI) fly ash by rice husk ash (RHA) is under intense study as an effective strategy to recover and reuse industrial and agricultural waste together. We compare the metal entrapment performances of RHA from different Asian rice sources – namely from Japonica rice grown in Italy and Indica rice grown in India – Physicochemical and morphological characterization of the final stabilized material show that the same thermal treatment may result in marked structural differences in the silica contained in the two RHA. Remarkably, one of them displays a crystalline silica content, although obtained by a thermal treatment below 800 °C. We also find that the presence of an alkali metal ion (potassium) in the rice husk plays a crucial role in the attainment of the final silica phase. These physicochemical differences are mirrored by different stabilization yields by the two RHA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Phylogenetic diversity and relationships among 40 rice accessions ...

    African Journals Online (AJOL)

    RAPDs were highly polymorphic, more discriminatory and informative as they were able to differentiate more pairs of accessions than the botanical descriptors. IITA rice accessions TOX 3052-46-3-3-2-1 and TOX 3027-44-1-E4-2-2 and Brazilian accessions (CL SELECCION 3B and 450) that performed better than checks ...

  3. THE COMPRESSIVE AND FLEXURAL STRENGTHS OF SELF-COMPACTING CONCRETE USING RAW RICE HUSK ASH

    Directory of Open Access Journals (Sweden)

    MD NOR ATAN

    2011-12-01

    Full Text Available This study investigates the compressive and flexural strengths of self-compacting concrete incorporating raw rice husk ash, individually and in combination with other types of mineral additives, as partial cement replacement. The additives paired with raw rice husk ash were fine limestone powder, pulverized fuel ash and silica fumes. The mix design was based on the rational method where solid constituents were fixed while water and superplasticizer contents were adjusted to produce optimum viscosity and flowability. All mixes were designed to achieve SF1 class slump-flow with conformity criteria ≥ 520 mm and ≤ 700 mm. Test results show that 15% replacement of cement using raw rice husk ash produced grade 40 concrete. It was also revealed that 30% and 45% cement replacements using raw rice husk ash combined with limestone powder and raw rice husk ash combined with limestone powder and silica fume respectively, produced comparable compressive strength to normal concrete and improved flexural strengths.

  4. Silica extraction from geothermal water

    Science.gov (United States)

    Bourcier, William L; Bruton, Carol J

    2014-09-23

    A method of producing silica from geothermal fluid containing low concentration of the silica of less than 275 ppm includes the steps of treating the geothermal fluid containing the silica by reverse osmosis treatment thereby producing a concentrated fluid containing the silica, seasoning the concentrated fluid thereby producing a slurry having precipitated colloids containing the silica, and separating the silica from the slurry.

  5. Brazilian Firms

    Directory of Open Access Journals (Sweden)

    Vicente Lima Crisóstomo

    2016-01-01

    Full Text Available This work makes an analysis of the determinants of Corporate Social Responsibility (CSR of Brazilian firms, as proxied by firm membership of the ISE Index of BM&FBOVESPA. Besides other proposed determinants of CSR present in the literature (firm size, profitability, growth opportunities, the work examines ownership concentration and the persistence on CSR status. Logit regression estimates have been run for a sample of 1649 firm-year observations in the period 2006-2011. The findings show that CSR of Brazilian firms is inversely correlated to its ownership concentration indicating that controlling voting shareholders may not see social concerns as a priority. Besides, firms tend to maintain their present CSR status. The results also indicate that leading CSR firms are larger, face more growth opportunities, and are persistent in their superior CSR situation.

  6. Brazilian energy

    Energy Technology Data Exchange (ETDEWEB)

    O`Shaughnessy, H.

    1997-04-01

    Brazilian Energy provides all the information necessary for energy companies to invest and operate in Brazil, including: a review of Brazil`s natural resources; an assessment of privatisation strategies at the federal, state and regional level; an analysis of the electricity industry and the future for Electrobras; an analysis of the oil industry and, in particular, Petrobras; a discussion of the fuel alcohol industry; the discovery of local natural gas, its prospects and the involvement of the auto industry; an assessment of the problems facing the coal industry and its future; a discussion of the regulatory framework for the newly privatised companies; the importance of intra-regional energy links and the booming membership of Mercosur; the difficulties experienced by foreign investors doing business in Brazil; brief profiles of the key energy companies; profiles of key people influencing the privatisation process in Brazil. Brazilian energy is essential reading for those wishing to advise and assist Brazil in this period of change and development, as well as those who wish to invest or become key players in the Brazilian energy sector. (author)

  7. The effectiveness of commercial desiccants and uncooked rice in removing moisture from hearing aids.

    Science.gov (United States)

    Nelson, Lauri H; White, Karl R; Baker, Dirk V; Hayden, Angela; Bird, Scott

    2017-04-01

    In many low- and middle-income countries, the availability of hearing technology is limited, with few options for hearing aid repairs. Minimising moisture damage to hearing aid electronics improves function and longevity; however, desiccants that absorb moisture from hearing aid components are unavailable in many regions. This study compared the effectiveness of uncooked white rice and seven commercial silica gel desiccants in removing moisture from hearing aids. Relative humidity measurements in a test chamber were obtained from a water-saturated BTE hearing aid prior to and after placement in uncooked white rice and seven different silica gel desiccants. Two BTE hearing aids, seven silica gel desiccants and white rice comprised the study sample. All desiccants and the white rice were effective in removing moisture from hearing aids, with Hal Hen Super Dri Aid showing the largest mean reduction in relative humidity. Based on analysis of covariance results, white rice was statistically similar to several of the commercial desiccants. White rice shows promise as an effective alternative to commercial desiccants in reducing moisture in hearing aids when silica gel products are unavailable. As this study was conducted in a relatively dry region, additional research may be needed.

  8. UTILIZATION OF RICE HUSK AS RAW MATERIAL IN SYNTHESIS OF MESOPOROUS SILICATES MCM-41

    Directory of Open Access Journals (Sweden)

    Suyanta Suyanta

    2011-12-01

    Full Text Available The research about synthesis and characterization of MCM-41 from rice husk has been done. Silica (SiO2 was extracted from rice husk by refluxing with 3M hydrochloric solution at 80 °C for 3 h. The acid-leached rice husk was filtered, washed, dried and calcined at 650 °C for 6 h lead the rough powder of rice husk silica with light brown in color. Characterization was carried out by X-ray diffraction (XRD and FTIR spectroscopy method. Rice husk silica was dissolved into the sodium hydroxide solution leading to the solution of sodium silicate, and used as silica source for the synthesis of MCM-41. MCM-41 was synthesized by hydrothermal process to the mixture prepared from 29 g of distilled water, 8.67 g of cetyltrimethyl ammonium bromide (CTMAB, 9.31 g of sodium silicate solution, and amount mL of 1 M H2SO4. Hydrothermal process was carried out at 100 °C in a teflon-lined stainless steel autoclave heated in the oven for 36 h. The solid phase was filtered, then washed with deionised water, and dried in the oven at 100 °C for 2 h. The surfactant CTMAB was removed by calcination at 550 °C for 10 h with heating rate 2 °C/min. The as-synthesized and calcined crystals were characterized by using FTIR spectroscopy, X-ray diffraction and N2 physisorption methods. In order to investigate the effect of silica source, the same procedure was carried out by using pure sodium silicate as silica source. It was concluded that silica extracted from rice husk can be used as raw materials in the synthesis of MCM-41, there is no significant difference in crystallinity and pore properties when was compared to material produced from commercial sodium silicate.

  9. SÍNTESE DA PENEIRA MOLECULAR MCM-41 DERIVADA DA CINZA DA CASCA DO ARROZ/SYNTHESIS OF MCM-41 MOLECULAR SIEVE DERIVED FROM RICE HUSK ASH

    National Research Council Canada - National Science Library

    R M Braga; N M Teodoro; F M Aquino; J M F Barros; D M A Melo; J C O Freitas

    2013-01-01

    .... In this article, MCM-41 was synthesized from rice husk ash, natural and chemically treated, as alternative sources of silica, called CCA-MCM-41 and CCAL-MCM-41, respectively, with the aim of reusing...

  10. Microporous silica membranes

    DEFF Research Database (Denmark)

    Boffa, Vittorio; Yue, Yuanzheng

    2012-01-01

    Hydrothermal stability is a crucial factor for the application of microporous silica-based membranes in industrial processes. Indeed, it is well established that steam exposure may cause densification and defect formation in microporous silica membranes, which are detrimental to both membrane...... permeability and selectivity. Numerous previous studies show that microporous transition metal doped-silica membranes are hydrothermally more stable than pure silica membranes, but less permeable. Here we present a quantitative study on the impact of type and concentration of transition metal ions...... on the microporous structure, stability and permeability of amorphous silica-based membranes, providing information on how to design chemical compositions and synthetic paths for the fabrication of silica-based membranes with a well accessible and highly stabile microporous structure....

  11. Preparation of porous bio-char and activated carbon from rice husk by leaching ash and chemical activation.

    Science.gov (United States)

    Ahiduzzaman, Md; Sadrul Islam, A K M

    2016-01-01

    Preparation porous bio-char and activated carbon from rice husk char study has been conducted in this study. Rice husk char contains high amount silica that retards the porousness of bio-char. Porousness of rice husk char could be enhanced by removing the silica from char and applying heat at high temperature. Furthermore, the char is activated by using chemical activation under high temperature. In this study no inert media is used. The study is conducted at low oxygen environment by applying biomass for consuming oxygen inside reactor and double crucible method (one crucible inside another) is applied to prevent intrusion of oxygen into the char. The study results shows that porous carbon is prepared successfully without using any inert media. The adsorption capacity of material increased due to removal of silica and due to the activation with zinc chloride compared to using raw rice husk char. The surface area of porous carbon and activated carbon are found to be 28, 331 and 645 m(2) g(-1) for raw rice husk char, silica removed rice husk char and zinc chloride activated rice husk char, respectively. It is concluded from this study that porous bio-char and activated carbon could be prepared in normal environmental conditions instead of inert media. This study shows a method and possibility of activated carbon from agro-waste, and it could be scaled up for commercial production.

  12. Rice peasants and rice research in Colombia

    NARCIS (Netherlands)

    Spijkers, P.A.N.M.

    1983-01-01

    Rice has been grown as a food crop in Latin America from early colonial times. In Colombia rice became a prominent subsistence crop especially on the north coast where it has been grown since the 17th century, sometimes also as a commercial crop. During the last twenty years there has been a sharp

  13. A new parameter-free soft-core potential for silica and its application to simulation of silica anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Izvekov, Sergei, E-mail: sergiy.izvyekov.civ@mail.mil; Rice, Betsy M. [Weapons and Materials Research Directorate, U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005 (United States)

    2015-12-28

    A core-softening of the effective interaction between oxygen atoms in water and silica systems and its role in developing anomalous thermodynamic, transport, and structural properties have been extensively debated. For silica, the progress with addressing these issues has been hampered by a lack of effective interaction models with explicit core-softening. In this work, we present an extension of a two-body soft-core interatomic force field for silica recently reported by us [S. Izvekov and B. M. Rice, J. Chem. Phys. 136(13), 134508 (2012)] to include three-body forces. Similar to two-body interaction terms, the three-body terms are derived using parameter-free force-matching of the interactions from ab initio MD simulations of liquid silica. The derived shape of the O–Si–O three-body potential term affirms the existence of repulsion softening between oxygen atoms at short separations. The new model shows a good performance in simulating liquid, amorphous, and crystalline silica. By comparing the soft-core model and a similar model with the soft-core suppressed, we demonstrate that the topology reorganization within the local tetrahedral network and the O–O core-softening are two competitive mechanisms responsible for anomalous thermodynamic and kinetic behaviors observed in liquid and amorphous silica. The studied anomalies include the temperature of density maximum locus and anomalous diffusivity in liquid silica, and irreversible densification of amorphous silica. We show that the O–O core-softened interaction enhances the observed anomalies primarily through two mechanisms: facilitating the defect driven structural rearrangements of the silica tetrahedral network and modifying the tetrahedral ordering induced interactions toward multiple characteristic scales, the feature which underlies the thermodynamic anomalies.

  14. Crystalline Silica Primer

    Science.gov (United States)

    ,

    1992-01-01

    Crystalline silica is the scientific name for a group of minerals composed of silicon and oxygen. The term crystalline refers to the fact that the oxygen and silicon atoms are arranged in a threedimensional repeating pattern. This group of minerals has shaped human history since the beginning of civilization. From the sand used for making glass to the piezoelectric quartz crystals used in advanced communication systems, crystalline silica has been a part of our technological development. Crystalline silica's pervasiveness in our technology is matched only by its abundance in nature. It's found in samples from every geologic era and from every location around the globe. Scientists have known for decades that prolonged and excessive exposure to crystalline silica dust in mining environments can cause silicosis, a noncancerous lung disease. During the 1980's, studies were conducted that suggested that crystalline silica also was a carcinogen. As a result of these findings, crystalline silica has been regulated under the Occupational Safety and Health Administration's (OSHA) Hazard Communication Standard (HCS). Under HCS, OSHAregulated businesses that use materials containing 0.1% or more crystalline silica must follow Federal guidelines concerning hazard communication and worker training. Although the HCS does not require that samples be analyzed for crystalline silica, mineral suppliers or OSHAregulated

  15. Cooked rice texture and rice flour pasting properties; impacted by rice temperature during milling

    OpenAIRE

    Saleh, Mohammed; Meullenet, Jean-Francois

    2013-01-01

    Rice milling plays a key factor in determining rice quality and value. Therefore accurate quality assessments are critical to the rice industry. This study was undertaken to assess the effect of exposing rice to elevated temperatures during milling, on cooked rice texture and rice flour pasting properties. Two long (Cybonnett and Francis) and one medium (Jupiter) rice (oryzae sativa L.) cultivars were milled using McGill laboratory mill for 30 and 40 s after warmed up the mill before milling....

  16. Silica, Silicosis and Autoimmunity.

    Directory of Open Access Journals (Sweden)

    Kenneth Michael Pollard

    2016-03-01

    Full Text Available Inhalation of dust containing crystalline silica is associated with a number of acute and chronic diseases including systemic autoimmune diseases. Evidence for the link with autoimmune disease comes from epidemiological studies linking occupational exposure to crystalline silica dust with the systemic autoimmune diseases SLE, SSc and RA. Although little is known regarding the mechanism by which silica exposure leads to systemic autoimmune disease, there is a voluminous literature on silica exposure and silicosis that may help identify immune processes that precede development of autoimmunity. The pathophysiology of silicosis consists of deposition of silica particles in the alveoli of the lung. Ingestion of these particles by macrophages initiates an inflammatory response which stimulates fibroblasts to proliferate and produce collagen. Silica particles are encased by collagen leading to fibrosis and the nodular lesions characteristic of the disease. The steps in the development of silicosis, including acute and chronic inflammation and fibrosis, have different molecular and cellular requirements suggesting that silica-induced inflammation and fibrosis may be mechanistically separate. Significantly, it is unclear whether silica-induced inflammation and fibrosis contribute similarly to the development of autoimmunity. Nonetheless, the findings from human and animal model studies are consistent with an autoimmune pathogenesis that begins with activation of the innate immune system leading to proinflammatory cytokine production, pulmonary inflammation leading to activation of adaptive immunity, breaking of tolerance, autoantibodies and tissue damage. The variable frequency of these immunological features following silica exposure suggests substantial genetic involvement and gene/environment interaction in silica-induced autoimmunity. However numerous questions remain unanswered.

  17. pozzolanicity and some engineering properties of rice husk ash

    African Journals Online (AJOL)

    HON

    (Neville, 1996). Rice Husks have been found to contain very high silica content, slow firing at a room temperature of 500 to 700 degrees Celsius. (Roy, 1987). The resulting ash is amorphous with a porous structure (Massazza, 1979). The ash has a specific surface as high as 50,000m2/kg and a specific gravity of 1.9 to 2.4 ...

  18. Conversion of rice hull ash into soluble sodium silicate

    OpenAIRE

    Edson Luiz Foletto; Ederson Gratieri; Leonardo Hadlich de Oliveira; Sérgio Luiz Jahn

    2006-01-01

    Sodium silicate is used as raw material for several purposes: silica gel production, preparation of catalysts, inks, load for medicines, concrete hardening accelerator, component of detergents and soaps, refractory constituent and deflocculant in clay slurries. In this work sodium silicate was produced by reacting rice hull ash (RHA) and aqueous sodium hydroxide, in open and closed reaction systems. The studied process variables were time, temperature of reaction and composition of the reacti...

  19. Growth and physiological responses of maize (Zea mays L.) to porous silica nanoparticles in soil

    Energy Technology Data Exchange (ETDEWEB)

    Suriyaprabha, R.; Karunakaran, G.; Yuvakkumar, R.; Prabu, P.; Rajendran, V., E-mail: veerajendran@gmail.com [K. S. Rangasamy College of Technology, Centre for Nano Science and Technology (India); Kannan, N. [K. S. Rangasamy College of Arts and Science, Department of Biotechnology (India)

    2012-12-15

    The present study aims to explore the effect of high surface area (360.85 m{sup 2} g{sup -1}) silica nanoparticles (SNPs) (20-40 nm) extracted from rice husk on the physiological and anatomical changes during maize growth in sandy loam soil at four concentrations (5-20 kg ha{sup -1}) in comparison with bulk silica (15-20 kg ha{sup -1}). The plant responses to nano and bulk silica treatments were analyzed in terms of growth characteristics, phyto compounds such as total protein, chlorophyll, and other organic compounds (gas chromatography-mass spectroscopy), and silica accumulation (high-resolution scanning electron microscopy). Growth characteristics were much influenced with increasing concentration of SNPs up to 15 kg ha{sup -1} whereas at 20 kg ha{sup -1}, no significant increments were noticed. Silica accumulation in leaves was high at 10 and 15 kg ha{sup -1} (0.57 and 0.82 %) concentrations of SNPs. The observed physiological changes show that the expression of organic compounds such as proteins, chlorophyll, and phenols favored to maize treated with nanosilica especially at 15 kg ha{sup -1} compared with bulk silica and control. Nanoscale silica regimes at 15 kg ha{sup -1} has a positive response of maize than bulk silica which help to improve the sustainable farming of maize crop as an alternative source of silica fertilizer.

  20. Rice that Filipinos Grow and Eat

    OpenAIRE

    de Leon, John C.

    2011-01-01

    This paper introduces rice to the reader and analyzes the changes it has gone through these past 100 years in the shaping hands of varietal improvement science. Here, the richness of the crop as a genetic material and resource is revealed. Landrace rice, pureline selection rice, crossbred rice, semidwarf rice, hybrid rice, new plant type rice, designer rice - from the traditional to modern to futuristic - rice becomes all of these while traversing time in the Philippines. There is rice for th...

  1. Evaluation of rice husk ash as filler in tread compounds

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, M. R. S., E-mail: monica.fernandes@lanxess.com [Lanxess Elastômeros do Brasil S.A., Brasil and Instituto de Química, Universidade do Estado do Rio de Janeiro (UERJ) (Brazil); Furtado, C. R. G., E-mail: russi@globo.com, E-mail: ana.furtado.sousa@gmail.com; Sousa, A. M. F. de, E-mail: russi@globo.com, E-mail: ana.furtado.sousa@gmail.com [Instituto de Química, Universidade do Estado do Rio de Janeiro (UERJ) (Brazil)

    2014-05-15

    Rice which is one of the largest agriculture crops produces around 22% of rice rusk during its milling process. This material is mainly used as fuel for energy generation, which results in an ash, which disposal represents an environmental issue. The rice husk ash (RHA) contains over than 70% of silica in an amorphous form and a lot of applications is being developed for it all over the world. The use of silica as a filler in the tire industry is growing since it contributes significantly to the reduction of fuel consumption of the automobiles, allowing at the same time better traction (safety). This paper presents an evaluation of the use of RHA as filler in rubber tread compounds prepared in lab scale and compares its performance with compounds prepared with commercial silica and carbon black, the fillers normally used in tire industry. Mechanical and rheological properties are evaluated, with emphasis for tan delta as an indicator of tread performance related with rolling resistance (fuel consumption) and wet grip/traction (safety)

  2. Silica from Ash

    Indian Academy of Sciences (India)

    Chemical. Tech.) ... waste disposal but also recovers a valuable silica product, together with certain useful associate recoveries. ... (consisting of residue digested ash, sodium-silicate, water and free sodium hydroxide). In the second step of the ...

  3. What Is Crystalline Silica?

    Science.gov (United States)

    ... carcinogen. Additionally, breathing crystalline silica dust can cause silicosis , which in severe cases can be disabling, or ... take in oxygen. There is no cure for silicosis. Since silicosis affects lung function, it makes one ...

  4. The improvement of rice straw quality by urea-molasses treatment

    Directory of Open Access Journals (Sweden)

    Tambak Manurung

    1996-03-01

    Full Text Available A study was conducted in Balai Penelitian Temak Bogor to evaluate the effect of urea-molasses treatment on the quality of rice straw . Five levels of urea were 0%, 0.5%, 1%, 1 .5% and 2% and 4 levels of molasses were 0%, I%, 2% and 3%. The study was conducted based on factorial completely randomized design with 3 replications . Urea and molasses were mixed with 5 kg chopped rice straw and stored for 21 days in plastic bag . Parameters observed were dry matter, organic matter, crude protein, crude fibre, and silica contents . Nutritive value of rice straw was measured by proximate analysis and its nutrient digestibility by in-vitro using rumen liquid of fistulated Ongole-crossed cattle . The results showed that urea and molasses treatment on rice straw decreased the dry matter and silica contents but increased the crude protein content of rice straw (P<0 .01. Dry matter and organic matter digestibility of rice straw didn't show the significant different among urea treatment but highly significant increased (P<0.01 by the molasses treatment. It was concluded that urea and molasses treatment on rice straw could improve the quality so that by the levels of 1 .5% urea and 3% molasses produced the similar quality with napier grass .

  5. Fermentation Quality and Additives: A Case of Rice Straw Silage

    Science.gov (United States)

    Oladosu, Yusuff; Magaji, Usman; Hussin, Ghazali; Ramli, Asfaliza; Miah, Gous

    2016-01-01

    Rice cultivation generates large amount of crop residues of which only 20% are utilized for industrial and domestic purposes. In most developing countries especially southeast Asia, rice straw is used as part of feeding ingredients for the ruminants. However, due to its low protein content and high level of lignin and silica, there is limitation to its digestibility and nutritional value. To utilize this crop residue judiciously, there is a need for improvement of its nutritive value to promote its utilization through ensiling. Understanding the fundamental principle of ensiling is a prerequisite for successful silage product. Prominent factors influencing quality of silage product include water soluble carbohydrates, natural microbial population, and harvesting conditions of the forage. Additives are used to control the fermentation processes to enhance nutrient recovery and improve silage stability. This review emphasizes some practical aspects of silage processing and the use of additives for improvement of fermentation quality of rice straw. PMID:27429981

  6. Diazotrophic bacteria isolated from wild rice Oryza glumaepatula (Poaceae in the Brazilian Amazon Bacterias diazotróficas aisladas de arroz silvestre Oryza glumaepatula (Poaceae en la Amazonia brasileña

    Directory of Open Access Journals (Sweden)

    Paulo Ivan Fernandes Júnior

    2013-06-01

    Full Text Available The association of wild grasses with diazotrophic bacteria in Brazilian biomes is poorly understood. The isolation and characterization of bacteria associated with wild grasses can contribute to understand the diazotrophic ecology as well as to identify bacteria with biotechnological applications. In this study, we isolated and characterized diazotrophic bacterial isolates from Oryza glumaepatula collected in Cerrado and Forest areas of the Amazon in Roraima State, Brazil. Healthy O. glumepatula plants were collected at five sampling sites at Forest and seven at Cerrado, respectively. The plants were collected at the Cerrado areas in September 2008 while the Forest plants were collected in June/2008 and April/2009. The plants and the soil adhering to the roots were transferred to pots and grown for 35 days in greenhouse conditions. During the harvest, the shoots and the roots were crushed separately in a saline solution; the suspension was diluted serially and inoculated in Petri dishes containing Dyg’s medium. All distinct bacterial colonies were purified in the same medium. The diazotrophic capacity of each bacterium in microaerophilic conditions was assessed in semisolid BMGM medium. In addition, the pellicles forming bacterial isolates were also evaluated by PCR amplification for nifH gene. The diversity of nifH+ bacteria was analyzed by Box-PCR fingerprinting. For selected strains, the growth promoting capacity of O. sativa as a model plant was also evaluated. A total of 992 bacterial isolates were obtained. Fifty- one bacteria were able to form pellicles in the semisolid medium and 38 also positively amplified the 360bp nifH gene fragment. Among the 38 nifH+ isolates, 24 were obtained from the shoots, while 14 originated from the roots. The Box-PCR profiles showed that the bacterial isolates obtained in this study presented a low similarity with the reference strains belonging to the Herbaspirillum, Azospirillum and Burkholderia genus

  7. Valorization of rice straw waste: an alternative ceramic raw material

    Directory of Open Access Journals (Sweden)

    Á. Guzmán A

    2015-03-01

    Full Text Available In the production of rice a large amount of solid residue is produced, for which alternative utilizations are scarce or are not commonly applied in industry. Rice straw (RS is a waste product of rice harvest that is generated in equal or greater quantities than the rice itself. RS is frequently burned in open air, which makes it a significant source of pollution. In the search for possible uses of RS, it should be noted that its ash (RSA is particularly rich in silica, alkaline and alkaline earth metals and may be used as a source of alkalis and silica for the production of triaxial ceramics. The present research work proposes the production of a ceramic raw material from RS for its use in the fabrication of ceramic materials for the construction industry. Based on the chemical and mineralogical composition of RSA created under different thermal conditions, the most suitable RSA for this purpose was that obtained from treating RS at a temperature of 800 ºC for a time of 2 h. The resulting RSA presented high contents of SiO2 (79.62%, alkaline oxides (K2O (10.53% and alkaline earth oxides (CaO (2.80%. It is concluded that RSA is a new alternative ceramic raw material that can be used as a replacement for the fluxing (mainly feldspar and inert (quartz materials that are used in the production of triaxial ceramics.

  8. High-performance silica/silica fiber for endoscopic applications

    Science.gov (United States)

    McCann, Brian P.

    1993-05-01

    Silica-core/silica-clad fibers have become very popular tools for a variety of therapeutic and diagnostic applications. Two types of conventional silica/silica fibers having acrylate and polyimide coatings are reviewed. The properties of dual-waveguide silica/silica fiber are discussed; and the superior bend performance with this design is presented. Silicone/nylon and hard-fluoropolymer/TefzelTM dual-coated fibers are included as the dual-waveguide samples. Sample fibers of each of the four coating types were manufactured into 400/440 micrometers size, 0.22 NA fiber.

  9. Determinants for grading Malaysian rice

    Science.gov (United States)

    ChePa, Noraziah; Yusoff, Nooraini; Ahmad, Norhayati

    2016-08-01

    Due to un-uniformity of rice grading practices in Malaysia, zones which actively producing rice in Malaysia are using their own way of grading rice. Rice grading is important in determining rice quality and its subsequent price in the market. It is an important process applied in the rice production industry with the purpose of ensuring that the rice produced for the market meets the quality requirements of consumer. Two important aspects that need to be considered in determining rice grades are grading technique and determinants to be used for grading (usually referred as rice attributes). This article proposes the list of determinants to be used in grading Malaysian rice. Determinants were explored through combination of extensive literature review and series of interview with the domain experts and practitioners. The proposed determinants are believed to be beneficial to BERNAS in improving the current Malaysian rice grading process.

  10. Synthesis of SiC from rice husk in a plasma reactor

    Indian Academy of Sciences (India)

    Unknown

    The plasma treated sample was found to be green in colour and fragile in nature, thus could easily ground in a mortar and pestle. The sample was then characterized by XRD (Philips ADP 1700) for phase analysis and SEM (JEOL 35 CF and JEOL JSM 5800). 3. Results and discussion. Rice husk contains silica in hydrated ...

  11. Mercury uptake by biogenic silica modified with L-cysteine.

    Science.gov (United States)

    Chaves, Marcia R M; Valsaraj, Kalliat T; DeLaune, Ronald D; Gambrell, Robert P; Buchler, Pedro M

    2011-10-01

    Contaminated sediments provide the main source of mercury for methylation by bacteria in lakes and waterways. In situ capping has been used to remediate these sediments, but traditional reactive materials have very low affinity for Hg(II). This study investigated the mercury uptake by biogenic silica modified with L-cysteine, as a potential material to be used for in situ remediation technologies. The adsorbent was obtained from rice hull ash by extraction as sodium silicate and acid hydrolysis through the sol-gel process; it was then modified with L-cysteine by impregnation from aqueous solution. The unmodified and modified biogenic silica showed structural and chemical properties suitable for mercury sorption from aqueous medium. The cysteine affected the structural properties of the unmodified silica, decreasing the specific surface area and pore volume by eightfold. On the other hand, cysteine increased the silica adsorption capacity, resulting in mercury uptake similar to that of the unmodified silica. The Hg(ll) specific adsorption by unmodified and modified silica was 0.20 mmol/g and 0.19 mmol/g SiO2, respectively, from an aqueous solution of 1 mmol/L Hg(II). The pH range of 3-7did not have an effect on Hg(II) adsorption. However, the presence of chlorine, added as HgCl2, seems to have limited the mercury adsorption, especially at high concentrations of Hg(II). The mercury adsorbed on the silica surface could not be recovered using HCl even from concentrated solutions.

  12. Incidence of toxigenic fungi and zearalenone in rice grains from Brazil.

    Science.gov (United States)

    Savi, Geovana D; Piacentini, Karim C; Rocha, Liliana O; Carnielli-Queiroz, Lorena; Furtado, Bianca G; Scussel, Rahisa; Zanoni, Elton Torres; Machado-de-Ávila, Ricardo A; Corrêa, Benedito; Angioletto, Elidio

    2018-02-03

    Rice (Oryza sativa L.) is one of the most important food crops worldwide. In Brazil, the southern region is the area with the highest production of rice in the country and also has a high average daily intake of rice by the population. The mycoflora, mainly toxigenic Aspergillus and Fusarium species, the presence of AFB 1 , DON and ZEA in rice grains, as well as daily intake estimates for the Southern Brazilian population were evaluated. The rice grain samples were collected during the 2017 crop from different harvest periods. According to the mycological tests, the samples presented a high count of fungal colonies in the pre and post-harvest, where the incidence of the F. graminearum species complex (52%) was significantly predominant. This group can be responsible for ZEA production, as found in this study in parboiled rice, mainly because most of the isolated strains were producers of high ZEA levels in the pre-harvest (77%) and post-harvest after natural (79%) and artificial (75%) drying of the rice. Only ZEA showed significant results in the rice grain analyzed (60%) at levels of 90.56 to 126.31 μg/kg, where 36% of the samples were significantly higher than the current maximum limit stipulated in Brazilian regulations and by the European Commission. Despite this, the dietary exposure of ZEA estimated for the southern Brazilian population was below the provisional maximum tolerable daily intake level of 0.5 μg/kg body weight/day set at international regulations. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Rice (Oryza) hemoglobins

    Science.gov (United States)

    Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice (Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a sin...

  14. economics of rice production

    African Journals Online (AJOL)

    ABSTRACT. Local rice production is being promoted in Ghana to reduce the' dependence on im- ports, ensure stable low-prices food for the population and also create employment. This paper examines three rice production systems; Upland, Valley Bottom and Irri- gated, in the Upper East Region of Ghana with a view to ...

  15. Rice Water use efficiency and yield under continuous and intermittent irrigation

    Science.gov (United States)

    In the Brazilian state of Rio Grande do Sul, rice (Oryza sativa L.) is predominantly grown using continuous fl ood irrigation, which requires large quantities of fresh water. Due to increasing scarcity and demand for water, modern agricultural systems need to produce more food with less water. Th e ...

  16. Ocorrência de aflatoxinas em arroz consumido por militares do Exército Brasileiro por cromatografia em camada delgada e cromatografia líquida de alta eficiência Incidence of aflatoxins in rice to be consumed by militaries in the brazilian army by thin layer chromatography and high performance liquid chromatography methods

    Directory of Open Access Journals (Sweden)

    Jader Oliveira da Silva

    2008-08-01

    Full Text Available Fungos do gênero Aspergillus como A. flavus e A. parasiticus são capazes de produzir metabólitos secundários tóxicos denominados aflatoxinas. Estas espécies podem se desenvolver rapidamente em cereais sob condições favoráveis. A partir do conhecimento dos riscos à saúde decorrentes da presença de aflatoxinas em alimentos, foi realizado um levantamento para avaliar a presença de aflatoxinas em arroz beneficiado polido tipo I, destinado ao consumo dos militares do Exército Brasileiro. As amostras foram coletadas no armazém do 5º Batalhão de Suprimento do Exército Brasileiro, Curitiba-PR no período de novembro de 2003 a fevereiro de 2004 e avaliada a ocorrência de aflatoxinas B1, B2, G1 e G2, utilizando-se as técnicas de Cromatografia em Camada Delgada (CCD e Cromatografia Líquida de Alta Eficiência (CLAE. Objetivou-se, neste trabalho, contribuir com o controle de qualidade dos alimentos consumidos pelos militares da 5º Região Militar do Exército Brasileiro, no que se refere ao controle dos níveis de aflatoxinas e comparar as técnicas de CCD e CLAE. Do total de 30 amostras analisadas por cromatografia em camada delgada, não foi verificada em nenhuma a presença de aflatoxinas. De 26 amostras analisadas por cromatografia líquida de alta eficiência, seis (23,07% apresentaram positividade para aflatoxina B1 (AFB1, com níveis entre 0,54 e 2,04µg/kg e uma (3,84% apresentou presença de aflatoxina B2 (AFB2 com 1,84µg/kg.Aspergillus are fungal species like a A flavus and A parasiticus and they are able to develop secondary metabolites called mycotoxins. They grow quickly under ideal conditions. From the moment one discovered its danger for health resulted from the presence of aflatoxins in foods, an achievement was carried out to evaluate the presence of a mycotoxins lifiting in benefited polished rice type 1, used by Brazilian army. The samples were collected at " 5º Batalhão de Suprimento" (army departament from

  17. Kinetics of silica polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Weres, O.; Yee, A.; Tsao, L.

    1980-05-01

    The polymerization of silicic acid in geothermal brine-like aqueous solutions to produce amorphous silica in colloidal form has been studied experimentally and theoretically. A large amount of high quality experimental data has been generated over the temperature rang 23 to 100{sup 0}C. Wide ranges of dissolved silica concentration, pH, and sodium chloride concentration were covered. The catalytic effects of fluoride and the reaction inhibiting effects of aluminum and boron were studied also. Two basic processes have been separately studied: the formation of new colloidal particles by the homogeneous nucleation process and the deposition of dissolved silica on pre-existing colloidal particles. A rigorous theory of the formation of colloidal particles of amorphous silica by homogeneous nucleation was developed. This theory employs the Lothe-Pound formalism, and is embodied in the computer code SILNUC which quantitatively models the homogeneous nucleation and growth of colloidal silica particles in more than enough detail for practical application. The theory and code were extensively used in planning the experimental work and analyzing the data produced. The code is now complete and running in its final form. It is capable of reproducing most of the experimental results to within experimental error. It is also capable of extrapolation to experimentally inaccessible conditions, i.e., high temperatures, rapidly varying temperature and pH, etc.

  18. Dark septate endophyte decreases stress on rice plants

    Directory of Open Access Journals (Sweden)

    Silvana Gomes dos Santos

    Full Text Available Abstract Abiotic stress is one of the major limiting factors for plant development and productivity, which makes it important to identify microorganisms capable of increasing plant tolerance to stress. Dark septate endophytes can be symbionts of plants. In the present study, we evaluated the ability of dark septate endophytes isolates to reduce the effects of water stress in the rice varieties Nipponbare and Piauí. The experiments were performed under gnotobiotic conditions, and the water stress was induced with PEG. Four dark septate endophytes were isolated from the roots of wild rice (Oryza glumaepatula collected from the Brazilian Amazon. Plant height as well as shoot and root fresh and dry matter were measured. Leaf protein concentrations and antioxidant enzyme activity were also estimated. The dark septate endophytes were grown in vitro in Petri dishes containing culture medium; they exhibited different levels of tolerance to salinity and water stress. The two rice varieties tested responded differently to inoculation with dark septate endophytes. Endophytes promoted rice plant growth both in the presence and in the absence of a water deficit. Decreased oxidative stress in plants in response to inoculation was observed in nearly all inoculated treatments, as indicated by the decrease in antioxidant enzyme activity. Dark septate endophytes fungi were shown to increase the tolerance of rice plants to stress caused by water deficiency.

  19. Dark septate endophyte decreases stress on rice plants.

    Science.gov (United States)

    Santos, Silvana Gomes Dos; Silva, Paula Renata Alves da; Garcia, Andres Calderin; Zilli, Jerri Édson; Berbara, Ricardo Luis Louro

    Abiotic stress is one of the major limiting factors for plant development and productivity, which makes it important to identify microorganisms capable of increasing plant tolerance to stress. Dark septate endophytes can be symbionts of plants. In the present study, we evaluated the ability of dark septate endophytes isolates to reduce the effects of water stress in the rice varieties Nipponbare and Piauí. The experiments were performed under gnotobiotic conditions, and the water stress was induced with PEG. Four dark septate endophytes were isolated from the roots of wild rice (Oryza glumaepatula) collected from the Brazilian Amazon. Plant height as well as shoot and root fresh and dry matter were measured. Leaf protein concentrations and antioxidant enzyme activity were also estimated. The dark septate endophytes were grown in vitro in Petri dishes containing culture medium; they exhibited different levels of tolerance to salinity and water stress. The two rice varieties tested responded differently to inoculation with dark septate endophytes. Endophytes promoted rice plant growth both in the presence and in the absence of a water deficit. Decreased oxidative stress in plants in response to inoculation was observed in nearly all inoculated treatments, as indicated by the decrease in antioxidant enzyme activity. Dark septate endophytes fungi were shown to increase the tolerance of rice plants to stress caused by water deficiency. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  20. Epoxy Grout With Silica Thickener

    Science.gov (United States)

    Mcclung, C. E.

    1984-01-01

    Grout cures quickly, even in presence of hydraulic oil. Grout is mixture of aggregate particles, finely-divided silica, epoxy resin, and triethylenetetramine curing agent, with mixture containing about 85 percent silica and aggregate particle sand 15 percent resin and curing agent. Silica is thickening agent and keeps grout from sagging.

  1. Evaluation of the occluded carbon within husk phytoliths of 35 rice cultivars

    Science.gov (United States)

    Sun, Xing; Liu, Qin; Gu, Jie; Chen, Xiang; Zhu, Keya

    2016-12-01

    Rice is a well-known silicon accumulator. During its periods of growth, a great number of phytoliths are formed by taking up silica via the plant roots. Concurrently, carbon in those phytoliths is sequestrated by a mechanism of long-term biogeochemical processes within the plant. Phytolith occluded C (PhytOC) is very stable and can be retained in soil for longer than a millennium. In this study, we evaluated the carbon biosequestration within the phytoliths produced in rice seed husks of 35 rice cultivars, with the goal of finding rice cultivars with relatively higher phytolith carbon sequestration efficiencies. The results showed that the phytolith contents ranged from 71.6 mg•g‒1 to 150.1 mg•g‒1, and the PhytOC contents ranged from 6.4 mg•g‒1 to 38.4 mg•g‒1, suggesting that there was no direct correlation between the PhytOC content and the content of rice seed husk phytoliths ( R = 0.092, p>0.05). Of all rice cultivars, six showed a higher carbon sequestration efficiency in phytolith seed husks. Additionally, the carbon biosequestration within the rice seed husk phytoliths was approximately 0.45‒3.46 kg-e-CO2•ha‒1•yr‒1. These rates indicate that rice cultivars are a potential source of carbon biosequestration which could contribute to the global carbon cycle and climate change.

  2. Aniline incorporated silica nanobubbles

    Indian Academy of Sciences (India)

    Stearic acid functionalization allows the materials to be handled just as free molecules, for dissolution, precipitation, storage etc. The methodology adopted involves adsorption of aniline on the surface of gold nanoparticles with subsequent growth of a silica shell through monolayers, followed by the selective removal of the ...

  3. Technology development for ceramic powders and materials from rice phytoliths. A study on the separation process and production of silicon compound powder by catalytic reaction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Chun; Shin, Kyung Suk; Shim, Sun Ja; Oh, Sung Jin; Lee, Duck Yong; Kim, Byung Gyun [Myongji University, Seoul (Korea, Republic of)

    1995-07-01

    From rice hulls without catalyst and contained 14 wt% silica, about 7% of silicon carbide powder was obtained by carbon-thermal reaction at 1430{approx}1473 degree. under flowing argon. Addition of silica and Pt catalyst to the rice hull yielded about 10% of silicon carbide powder, and resulted in 40% increase in the yield of the powder. Treatment of the pyrolyzed products by hydrofluoric acid solution showed that silica content of the product was on an average 20%. Straight line shape whiskers of 0.1{mu}m in diameter and 20{mu}m in length were obtained from rice hulls with Pt catalyst, while addition of Ni, Co, or Fe yielded twisted whiskers. Recovery yield of silicon carbide and silica powder was about 7.8% by selective flocculation-liquid extraction recovery process. This result is comparable with the one obtained by burning pyrolyzed products to remove unreacted carbon in rice hull, which shows the yield of 7%. To increase the yield of silicon carbide powder and to produce straight line type silicon carbide whisker, it is recommended that pyrolysis temperature must be above 1430 degree, and Pt catalyst and silica may be added simultaneously to rice hull. (author). 22 refs., 39 figs., 16 tabs.

  4. Hydrothermal stability of silica, hybrid silica and Zr-doped hybrid silica membranes

    NARCIS (Netherlands)

    ten Hove, Marcel; Luiten-Olieman, Mieke W.J.; Huiskes, Cindy; Nijmeijer, Arian; Winnubst, Louis

    2017-01-01

    Hybrid silica membranes have demonstrated to possess a remarkable hydrothermal stability in pervaporation and gas separation processes allowing them to be used in industrial applications. In several publications the hydrothermal stability of pure silica or that of hybrid silica membranes are

  5. Cambodia Rice Sector Review

    OpenAIRE

    World Bank Group

    2015-01-01

    Cambodia’s rice harvests have been rising significantly since 2005, powered by improved and expanded irrigation and attractive farm gate prices. In 2010, the Cambodian government announced an export target of 1.0 million tons of milled rice by 2015. This analysis, which updates reports prepared in 2009 and 2011, seeks to identify short-term policy measures that can assist Cambodian exporte...

  6. Brazilian antidoping public policy.

    Science.gov (United States)

    Almeida, Claudio Bispo de; Rodrigues, Deyvis Nascimento

    2014-07-01

    Doping, used to improve sports performance, is legally prohibited. This paper describes Brazilian regulations, resolutions, and Federal laws addressing the issue of doping and antidoping which were collected in 2012 from official websites. We conclude that Brazilian laws have constrained doping, and have been updated over the years to conform to worldwide legal guidelines. Study limitations are noted.

  7. ERICA: intake of macro and micronutrients of Brazilian adolescents

    Directory of Open Access Journals (Sweden)

    Amanda de Moura Souza

    2016-02-01

    Full Text Available ABSTRACT OBJECTIVE To describe food and macronutrient intake profile and estimate the prevalence of inadequate micronutrient intake of Brazilian adolescents. METHODS Data from 71,791 adolescents aged from 12 to 17 years were evaluated in the 2013-2014 Brazilian Study of Cardiovascular Risks in Adolescents (ERICA. Food intake was estimated using 24-hour dietary recall (24-HDR. A second 24-HDR was collected in a subsample of the adolescents to estimate within-person variability and calculate the usual individual intake. The prevalence of food/food group intake reported by the adolescents was also estimated. For sodium, the prevalence of inadequate intake was estimated based on the Tolerable Upper Intake Level (UL. The Estimated Average Requirement (EAR method used as cutoff was applied to estimate the prevalence of inadequate nutrient intake. All the analyses were stratified according to sex, age group and Brazilian macro-regions. All statistical analyses accounted for the sample weight and the complex sampling design. RESULTS Rice, beans and other legume, juice and fruit drinks, breads and meat were the most consumed foods among the adolescents. The average energy intake ranged from 2,036 kcal (girls aged from 12 to 13 years to 2,582 kcal (boy aged from14 to 17 years. Saturated fat and free sugar intake were above the maximum limit recommended ( 50.0%. Sodium intake was above the UL for more than 80.0% of the adolescents. CONCLUSIONS The diets of Brazilian adolescents were characterized by the intake of traditional Brazilian food, such as rice and beans, as well as by high intake of sugar through sweetened beverages and processed foods. This food pattern was associated with an excessive intake of sodium, saturated fatty acids and free sugar.

  8. scale rice farmers in nigeria

    African Journals Online (AJOL)

    Admin

    of world rice, with China and India accounting for over half of the world's output. Worldwide, rice production has ... reported that rice indeed is no longer a luxury food in. Nigeria, and that it has become a major source of ... declined in China and Japan but this trend is not observed in other Asian countries; instead, the share ...

  9. Conversion of rice husk ash to zeolite beta.

    Science.gov (United States)

    Prasetyoko, Didik; Ramli, Zainab; Endud, Salasiah; Hamdan, Halimaton; Sulikowski, Bogdan

    2006-01-01

    White rice husk ash (RHA), an agriculture waste containing crystalline tridymite and alpha-cristobalite, was used as a silica source for zeolite Beta synthesis. The crystallization of zeolite Beta from RHA at 150 degrees C in the presence of tetraethylammonium hydroxide was monitored by XRD, FTIR and (29)Si MAS NMR techniques. It was found that zeolite Beta started to form after 12h and the complete crystallization of zeolite Beta phase was achieved after 2d. XRD, (29)Si MAS NMR and solid yield studies indicate that the transformation mechanism of silica present in RHA to zeolite Beta involves dissolution of the ash, formation of an amorphous aluminosilicate after 6h of crystallization, followed by dissolution in the mother liquor and final transformation to pure zeolite Beta crystals.

  10. Conversion of rice hull ash into soluble sodium silicate

    Directory of Open Access Journals (Sweden)

    Edson Luiz Foletto

    2006-09-01

    Full Text Available Sodium silicate is used as raw material for several purposes: silica gel production, preparation of catalysts, inks, load for medicines, concrete hardening accelerator, component of detergents and soaps, refractory constituent and deflocculant in clay slurries. In this work sodium silicate was produced by reacting rice hull ash (RHA and aqueous sodium hydroxide, in open and closed reaction systems. The studied process variables were time, temperature of reaction and composition of the reaction mixture (expressed in terms of molar ratios NaOH/SiO2 and H2O/SiO2. About 90% silica conversion contained in the RHA into sodium silicate was achieved in closed system at 200 °C. The results showed that sodium silicate production from RHA can generate aggregate value to this residue.

  11. Hydrothermal stability of microporous silica and niobia-silica membranes

    NARCIS (Netherlands)

    Boffa, V.; Blank, David H.A.; ten Elshof, Johan E.

    2008-01-01

    The hydrothermal stability of microporous niobia–silica membranes was investigated and compared with silica membranes. The membranes were exposed to hydrothermal conditions at 150 and 200 °C for 70 h. The change of pore structure before and after exposure to steam was probed by single-gas permeation

  12. A lucrative chemical processing of bamboo leaf biomass to synthesize biocompatible amorphous silica nanoparticles of biomedical importance

    Science.gov (United States)

    Rangaraj, Suriyaprabha; Venkatachalam, Rajendran

    2017-06-01

    Synthesis of silica nanoparticles from natural resources/waste via cost effective route is presently one of the anticipating strategies for extensive applications. This study reports the low-cost indigenous production of silica nanoparticles from the leftover of bamboo (leaf biomass) through thermal combustion and alkaline extraction, and examination of physico-chemical properties and yield percentage using comprehensive characterization tools. The outcome of primed silica powder exhibits amorphous particles (average size: 25 nm) with high surface area (428 m2 g-1) and spherical morphology. Despite the yield percentage of silica nanoparticles from bamboo leave ash is 50.2%, which is less than rice husk ask resources (62.1%), the bamboo waste is only an inexpensive resource yielding high purity (99%). Synthesis of silica nanoparticles from natural resources/waste with the help of lucrative route is at present times one of the anticipating strategies for extensive applications. In vitro study on animal cell lines (MG-63) shows non-toxic nature of silica nanoparticles up to 125 µg mL-1. Hence, this study highlights the feasibility for the mass production of silica nanoparticles from bamboo leave waste rather using chemical precursor of silica for drug delivery and other medical applications.

  13. Brazilian Consensus on Photoprotection

    Science.gov (United States)

    Schalka, Sérgio; Steiner, Denise; Ravelli, Flávia Naranjo; Steiner, Tatiana; Terena, Aripuanã Cobério; Marçon, Carolina Reato; Ayres, Eloisa Leis; Addor, Flávia Alvim Sant'anna; Miot, Helio Amante; Ponzio, Humberto; Duarte, Ida; Neffá, Jane; da Cunha, José Antônio Jabur; Boza, Juliana Catucci; Samorano, Luciana de Paula; Corrêa, Marcelo de Paula; Maia, Marcus; Nasser, Nilton; Leite, Olga Maria Rodrigues Ribeiro; Lopes, Otávio Sergio; Oliveira, Pedro Dantas; Meyer, Renata Leal Bregunci; Cestari, Tânia; dos Reis, Vitor Manoel Silva; Rego, Vitória Regina Pedreira de Almeida

    2014-01-01

    Brazil is a country of continental dimensions with a large heterogeneity of climates and massive mixing of the population. Almost the entire national territory is located between the Equator and the Tropic of Capricorn, and the Earth axial tilt to the south certainly makes Brazil one of the countries of the world with greater extent of land in proximity to the sun. The Brazilian coastline, where most of its population lives, is more than 8,500 km long. Due to geographic characteristics and cultural trends, Brazilians are among the peoples with the highest annual exposure to the sun. Epidemiological data show a continuing increase in the incidence of non-melanoma and melanoma skin cancers. Photoprotection can be understood as a set of measures aimed at reducing sun exposure and at preventing the development of acute and chronic actinic damage. Due to the peculiarities of Brazilian territory and culture, it would not be advisable to replicate the concepts of photoprotection from other developed countries, places with completely different climates and populations. Thus the Brazilian Society of Dermatology has developed the Brazilian Consensus on Photoprotection, the first official document on photoprotection developed in Brazil for Brazilians, with recommendations on matters involving photoprotection. PMID:25761256

  14. Climate Change Implications to Irrigated Rice Production in Southern Brazil: A Modelling Approach

    Science.gov (United States)

    Dos Santos, Thiago

    Rice is one of the staple foods for more than three billion people worldwide. When cultivated under irrigated conditions (i.e. lowland rice), rice is one of the most intensive water consumer crops globally. Therefore, representation of rice growth should be integrated into the latest land surface models to allow studies on food security and to ensure that accurate simulations of the bidirectional feedbacks between the land surface and atmosphere take place. In this study, I present a new process-based model for rice fields that includes rice growth and rice irrigation as modules within the Agro-IBIS dynamic agro-ecosystem model. The model includes a series of equations, agricultural management parameters and an irrigation scheme that are specifically tailored for rice crops. The model was evaluated against leaf area index and biomass observations, obtained for one growing season in Rio Grande do Sul state (southern Brazil), and in Los Banos, Philippines. The model accurately captured the temporal dynamics of leaf area index in both the Brazilian and the Philippine sites, and predicted end-of-season biomass with an error of between -9.5% and 11.3% depending on the location and the plant organ. Rice phenology is predicted by the model based on experimentally-derived growth rates, and was evaluated by comparing simulated and observed durations of the four growth phases considered by the model. Agro-IBIS showed a tendency to overestimate the duration of the growth stages between 3% and 16%, but underestimated by 8% the duration of the panicle formation phase in one growing season. The new irrigation model is based on the water balance at the surface and applies irrigation in order to keep the water layer at the paddy field always in the optimum level. A set of climate projections from global climate models under two emission scenarios, and excluding and considering CO2 fertilizations effects, was used to drive the updated Agro-IBIS to estimate the effects of climate

  15. Silica Fillers for elastomer Reinforement

    Energy Technology Data Exchange (ETDEWEB)

    Kohls, D.J.; Schaefer, D.W. (UCIN)

    2012-09-10

    This article summarizes recent work on the structure of precipitated silica used in the reinforcement of elastomers. Silica has a unique morphology, consisting of multiple structural levels that can be controlled through processing. The ability to control and characterize the multiple structures of precipitated silica is an example of morphological engineering for reinforcement applications. In this summary of some recent research efforts using precipitated silica, small-angle scattering techniques are described and their usefulness for determining the morphology of silica in terms of primary particles, aggregates, and agglomerates are discussed. The structure of several different precipitated silica powders is shown as well as the mechanical properties of elastomers reinforced with these silica particles. The study of the mechanical properties of filled elastomer systems is a challenging and exciting topic for both fundamental science and industrial application. It is known that the addition of hard particulates to a soft elastomer matrix results in properties that do not follow a straightforward rule of mixtures. Research efforts in this area have shown that the properties of filled elastomers are influenced by the nature of both the filler and the matrix, as well as the interactions between them. Several articles have reviewed the influence of fillers like silica and carbon black on the reinforcement of elastomers. In general, the structure-property relationships developed for filled elastomers have evolved into the following major areas: Filler structure, hydrodynamic reinforcement, and interactions between fillers and elastomers.

  16. Silica Fillers for elastomer Reinforement

    Energy Technology Data Exchange (ETDEWEB)

    Kohls, D.J.; Schaefer, D.W. (UCIN)

    2009-08-26

    This article summarizes recent work on the structure of precipitated silica used in the reinforcement of elastomers. Silica has a unique morphology, consisting of multiple structural levels that can be controlled through processing. The ability to control and characterize the multiple structures of precipitated silica is an example of morphological engineering for reinforcement applications. In this summary of some recent research efforts using precipitated silica, small-angle scattering techniques are described and their usefulness for determining the morphology of silica in terms of primary particles, aggregates, and agglomerates are discussed. The structure of several different precipitated silica powders is shown as well as the mechanical properties of elastomers reinforced with these silica particles. The study of the mechanical properties of filled elastomer systems is a challenging and exciting topic for both fundamental science and industrial application. It is known that the addition of hard particulates to a soft elastomer matrix results in properties that do not follow a straightforward rule of mixtures. Research efforts in this area have shown that the properties of filled elastomers are influenced by the nature of both the filler and the matrix, as well as the interactions between them. Several articles have reviewed the influence of fillers like silica and carbon black on the reinforcement of elastomers. In general, the structure-property relationships developed for filled elastomers have evolved into the following major areas: Filler structure, hydrodynamic reinforcement, and interactions between fillers and elastomers.

  17. Silica reinforced triblock copolymer gels

    DEFF Research Database (Denmark)

    Theunissen, E.; Overbergh, N.; Reynaers, H.

    2004-01-01

    The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has been investigated. Different types of chemically modified silica have been compared in order...... to evaluate the influence of the compatibility between gel and filler. Time-resolved SANS and small-angle X-ray scattering (SAXS) shows that the presence of silica particles affects the ordering of the polystyrene domains during gelsetting. The scattering pattern of silica-reinforced gels reveals strong...... scattering at very low q, but no structure and formfactor information. However, on heating above the viscoelastic to plastic transition, the 'typical' scattering pattern of the copolymer gel builds-up. All reinforced gels are strengthened by the addition of the reinforcing agent. The transitions from...

  18. 78 FR 14540 - Cyromazine, Silica Silicates (Silica Dioxide and Silica Gel), Glufosinate Ammonium, Dioctyl...

    Science.gov (United States)

    2013-03-06

    ... herbicide that acts by inhibiting glutamine synthetase, which leads to poisoning in plants via the...). Silica silicates, silicon dioxide and silica gel, are insecticides and acaracides used in controlling insects at indoor and outdoor sites including a variety of crops. Silicon dioxide is diatomaceous earth, a...

  19. HMG-CoA Reductase Inhibitors from Monascus-Fermented Rice

    Directory of Open Access Journals (Sweden)

    Xuemei Li

    2013-01-01

    Full Text Available Seven compounds were isolated from Monascus-fermented rice by column chromatography with silica gel and semiprep HPLC. Their structures were elucidated by extensive spectroscopic methods. All compounds displayed HMG-CoA reductase inhibitory potential, among them compound 7 exhibited strong inhibition with IC50 value comparable with lovastatin. In this study, two compounds (1 and 2 were obtained from natural source for the first time.

  20. Indigenous Brazilian Management Practices

    Directory of Open Access Journals (Sweden)

    Zandra Balbinot

    2012-12-01

    Full Text Available The present research seeks to understand to what extent companies in emerging countries, specifically, Brazilian, adopt dominant management practices, the so-called Euro-American practices, possess their one, or show a syncretism between the two. Methods: Mixed research. One phase was to collect data using a survey about cultural dimensions adopted from GLOBE (House 1998 management practices and also from Brazilian academy. Another was to collect data through interviews, which were analyzed in parallel. Results: Of the seven dominant cultural dimensions, indigenous practices influenced two. Another three were influenced by dominant management practices. Two of the local dimensions, even with internationalization, merged practices with Brazilian cultural traits. Even so, the practices derived from Jeitinho diminished relative to the international relations and experience of managers. Conclusions: The paper shows the existence of powerful Brazilian Indigenous Managerial Practices such as personalism and formalism. These practices have great influence on international business negotiations. On the other hand, it also shows that there are still dominant managerial practices specially in the case of more internationalized Brazilian managers

  1. Release of potassium accompanying the dissolution of rice straw phytolith.

    Science.gov (United States)

    Nguyen, Minh Ngoc; Dultz, Stefan; Picardal, Flynn; Bui, Anh Thi Kim; Pham, Quang Van; Schieber, Juergen

    2015-01-01

    In rice, Si assimilated from the soil solution is deposited in inter- and intracellular spaces throughout the leaf and stems to form silicified structures (so-called phytoliths). Because K is also present in significant concentrations in rice stems and leaves, the question arises if K is immobilized in the mineralized silica during the precipitation of Si. This work determined whether desilification of the phytolith is a factor regulating K release by implementing batch experiments. Solubility of Si and K of the rice straw heated at different temperatures were examined to identify effect of pretreatment. Analyses of phytoliths using SEM-EDX and X-ray tomographic microscopy in conjunction with the results from batch experiments revealed that K might co-exist with occluded organic matter inside the phytolith structure. In the kinetic experiments, corresponding increases of K and Si concentrations in the supernatants were observed which suggested that desilification of the phytolith is a main factor regulating K release. The extent of heat pretreatment of the rice straw is of significant importance with respect to dissolution of the phytolith by affecting organic removal and surface modification. At temperatures lower than 600 °C, corresponding increases of the soluble Si and K with heating temperature have been obviously observed. In contrast, the solubility of Si and K gradually decreased at temperatures above 600 °C. This work provides insights into factors that control release of K and Si from phytolith and a practical recommendation for practices of burning rice straw that may maximize subsequent release of Si and K for crops. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Defense Responses in Rice Induced by Silicon Amendment against Infestation by the Leaf Folder Cnaphalocrocis medinalis.

    Science.gov (United States)

    Han, Yongqiang; Li, Pei; Gong, Shaolong; Yang, Lang; Wen, Lizhang; Hou, Maolin

    2016-01-01

    Silicon (Si) amendment to plants can confer enhanced resistance to herbivores. In the present study, the physiological and cytological mechanisms underlying the enhanced resistance of plants with Si addition were investigated for one of the most destructive rice pests in Asian countries, the rice leaf folder, Cnaphalocrocis medinalis (Guenée). Activities of defense-related enzymes, superoxide dismutase, peroxidase, catalase, phenylalanine ammonia-lyase, and polyphenol oxidase, and concentrations of malondialdehyde and soluble protein in leaves were measured in rice plants with or without leaf folder infestation and with or without Si amendment at 0.32 g Si/kg soil. Silicon amendment significantly reduced leaf folder larval survival. Silicon addition alone did not change activities of defense-related enzymes and malondialdehyde concentration in rice leaves. With leaf folder infestation, activities of the defense-related enzymes increased and malondialdehyde concentration decreased in plants amended with Si. Soluble protein content increased with Si addition when the plants were not infested, but was reduced more in the infested plants with Si amendment than in those without Si addition. Regardless of leaf folder infestation, Si amendment significantly increased leaf Si content through increases in the number and width of silica cells. Our results show that Si addition enhances rice resistance to the leaf folder through priming the feeding stress defense system, reduction in soluble protein content and cell silicification of rice leaves.

  3. Defense Responses in Rice Induced by Silicon Amendment against Infestation by the Leaf Folder Cnaphalocrocis medinalis.

    Directory of Open Access Journals (Sweden)

    Yongqiang Han

    Full Text Available Silicon (Si amendment to plants can confer enhanced resistance to herbivores. In the present study, the physiological and cytological mechanisms underlying the enhanced resistance of plants with Si addition were investigated for one of the most destructive rice pests in Asian countries, the rice leaf folder, Cnaphalocrocis medinalis (Guenée. Activities of defense-related enzymes, superoxide dismutase, peroxidase, catalase, phenylalanine ammonia-lyase, and polyphenol oxidase, and concentrations of malondialdehyde and soluble protein in leaves were measured in rice plants with or without leaf folder infestation and with or without Si amendment at 0.32 g Si/kg soil. Silicon amendment significantly reduced leaf folder larval survival. Silicon addition alone did not change activities of defense-related enzymes and malondialdehyde concentration in rice leaves. With leaf folder infestation, activities of the defense-related enzymes increased and malondialdehyde concentration decreased in plants amended with Si. Soluble protein content increased with Si addition when the plants were not infested, but was reduced more in the infested plants with Si amendment than in those without Si addition. Regardless of leaf folder infestation, Si amendment significantly increased leaf Si content through increases in the number and width of silica cells. Our results show that Si addition enhances rice resistance to the leaf folder through priming the feeding stress defense system, reduction in soluble protein content and cell silicification of rice leaves.

  4. A practicable detection system for genetically modified rice by SERS-barcoded nanosensors.

    Science.gov (United States)

    Chen, Kun; Han, Heyou; Luo, Zhihui; Wang, Yanjun; Wang, Xiuping

    2012-04-15

    Since the global cultivation of genetically modified crops constantly expands, it remains a high demand to establish different ways to sort food and feed that consist or contain genetically modified organisms. Surface-enhanced Raman scattering (SERS) spectroscopy is a flexible tool for biological analysis due to its excellent properties for detecting wide varieties of target biomolecules including nucleic acids. In the present study, a SERS-barcoded nanosensor was developed to detect Bacillus thuringiensis (Bt) gene-transformed rice expressing insecticidal proteins. The barcoded sensor was designed by encapsulation of gold nanoparticles with silica and conjugation of oligonucleotide strands for targeting DNA strands. The transition between the cry1A(b) and cry1A(c) fusion gene sequence was used to construct a specific SERS-based detection method with a detection limit of 0.1 pg/mL. In order to build the determination models to screen transgene, a series mixture of Bt rice and normal rice were prepared for SERS assay, and the limit of detection was 0.1% (w/w) transgenic Bt rice relative to normal rice. The sensitivity and accuracy of the SERS-based assay was comparable with real-time PCR. The SERS-barcoded analytical method would provide precise detection of transgenic rice varieties but also informative supplement to avoid false positive outcomes. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  5. Accelerated Solvent Extraction of Insecticides from Rice Hulls, Rice Bran, and Polished Rice Grains.

    Science.gov (United States)

    Teló, Gustavo Mack; Senseman, Scott Allen; Marchesan, Enio; Camargo, Edinalvo Rabaioli; Carson, Katherine

    2017-03-01

    Analysis of pesticide residues in irrigated rice grains is important for food security. In this study, we analyzed accelerated solvent extraction (ASE) conditions for the extraction of thiamethoxam and chlorantraniliprole insecticides from rice hulls, rice bran, and polished rice grains. Several variables, including extraction solvent, extraction temperature, extraction pressure, cell size, static extraction time, and sample concentration, were investigated. The average recoveries of the three matrixes were between 89.7 and 109.7% at the fortification level of 0.75 mg/kg. The optimum ASE operating conditions were acetonitrile (100%) as extraction solvent, extraction temperature of 75°C for rice hulls and 100°C for rice bran and polished rice grains, extraction cell pressure of 10.3 MPa, 22 mL cell size, and two extraction cycles. The total extraction time was approximately 25 min. The extracted volume was evaporated to dryness and the residues were redissolved in 2 mL acetonitrile after 1 min of vortex-shaking. Thiamethoxam and chlorantraniliprole were analyzed by ultra-HPLC with tandem MS. In conclusion, ASE in rice hulls, rice bran, and polished rice grains offers the possibility of a fast and simple method for obtaining a quantitative extraction of the studied pesticides.

  6. 21 CFR 182.1711 - Silica aerogel.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Silica aerogel. 182.1711 Section 182.1711 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN....1711 Silica aerogel. (a) Product. Silica aerogel as a finely powdered microcellular silica foam having...

  7. 21 CFR 582.1711 - Silica aerogel.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Silica aerogel. 582.1711 Section 582.1711 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1711 Silica aerogel. (a) Product. Silica aerogel as a finely powdered microcellular silica foam having...

  8. Evaluation of metal ions in rice samples: extraction and direct determination by ICP OES

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Andrea; Cadore, Solange, E-mail: cadore@iqm.unicamp.br [Instituto de Quimica, Universidade Estadual de Campinas, Campinas-SP (Brazil); Baccan, Nivaldo [Faculdade de Paulinia, Paulinia-SP (Brazil)

    2012-05-15

    A method for extraction of metal ions present in rice samples using ammoniacal EDTA solution, pH = 10, as extractor agent is proposed under the following optimized conditions: 0.20 g of rice sample and 5.00 mL of ammoniacal EDTA (ethylenediaminetetraacetic acid) solution, with 5 min of ultrasound exposure time. Using robust ICP OES (inductively coupled plasma atomic emission spectrometry) conditions, direct analysis of the extraction solution was allowed, and the recovery values obtained were above 90% for most of the studied elements (P, K, Mg, Ca, Zn, Mn, Cu and Mo) with RSD < 5%. The results were in good agreement with those obtained by microwave assisted extraction and for the reference material of rice flour (NIST SRM 1568a). The limits of detection of method were in the range of 0.007 mg kg{sup -1} (Mn) - 48.68 mg kg{sup -1} (K), showing adequate detectability for the determination of the analytes. The analysis of different samples indicated that Brazilian 'integral' rice contains higher contents of the constituents studied, followed by 'parboiled' rice, and the 'agulhinha' rice a long and thin grain type. (author)

  9. Fuels and chemicals from rice straw in Egypt

    Energy Technology Data Exchange (ETDEWEB)

    Stahl, R. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Technische Chemie; Ramadan, A.B. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Technische Chemie]|[Atomic Energy Authority (AEA), Cairo (Egypt). National Centre for Nuclear Safety and Radiation Control

    2007-10-15

    separated before use. The pyrolysis process was studied on laboratory and PDU (process demonstration unit) scale. During pyrolysis lignin gave the main contribution to the char formation. TGA pyrolysis experiments showed about 60% of volatiles, 20% fixed carbon and 20% of ash on the average (dry). These results were very close to the results of fast pyrolysis experiments in a PDU with a twin-screw reactor. The chlorine was focussed in the pyrolysis char up to a temperature of {proportional_to}500 C. If the pyrolysis temperature exceeded 500 C the chlorine was released and its concentration in the chars decreased. The outside of the rice straw stems was completely covered with silica forming a close protection layer. SEM-studies show that the pyrolysis took place only at the inner sides of the stems. Therefore rice straw had to be chopped very carefully in order to brake up short stem pieces and to split them up. Additionally the SEM pictures confirmed the volatility of chlorine at temperatures above 500 C.

  10. Silica/Polymer and Silica/Polymer/Fiber Composite Aerogels

    Science.gov (United States)

    Ou, Danny; Stepanian, Christopher J.; Hu, Xiangjun

    2010-01-01

    Aerogels that consist, variously, of neat silica/polymer alloys and silica/polymer alloy matrices reinforced with fibers have been developed as materials for flexible thermal-insulation blankets. In comparison with prior aerogel blankets, these aerogel blankets are more durable and less dusty. These blankets are also better able to resist and recover from compression . an important advantage in that maintenance of thickness is essential to maintenance of high thermal-insulation performance. These blankets are especially suitable as core materials for vacuum- insulated panels and vacuum-insulated boxes of advanced, nearly seamless design. (Inasmuch as heat leakage at seams is much greater than heat leakage elsewhere through such structures, advanced designs for high insulation performance should provide for minimization of the sizes and numbers of seams.) A silica/polymer aerogel of the present type could be characterized, somewhat more precisely, as consisting of multiply bonded, linear polymer reinforcements within a silica aerogel matrix. Thus far, several different polymethacrylates (PMAs) have been incorporated into aerogel networks to increase resistance to crushing and to improve other mechanical properties while minimally affecting thermal conductivity and density. The polymethacrylate phases are strongly linked into the silica aerogel networks in these materials. Unlike in other organic/inorganic blended aerogels, the inorganic and organic phases are chemically bonded to each other, by both covalent and hydrogen bonds. In the process for making a silica/polymer alloy aerogel, the covalent bonds are introduced by prepolymerization of the methacrylate monomer with trimethoxysilylpropylmethacrylate, which serves as a phase cross-linker in that it contains both organic and inorganic monomer functional groups and hence acts as a connector between the organic and inorganic phases. Hydrogen bonds are formed between the silanol groups of the inorganic phase and the

  11. Nicaragua - Rice and Banana Farmers

    Data.gov (United States)

    Millennium Challenge Corporation — This report is an impact evaluation of two components of the Rural Business Development Program (RBD) in Nicaragua, specifically the components benefitting rice and...

  12. Injection molded plastic helical gear filled with carbon powder made from rice hull

    Science.gov (United States)

    Chen, Yen Chu; Itagaki, Takayoshi; Takahashi, Hideo; Takahashi, Mikio

    2017-07-01

    Natural materials are focused on the ecological responsibility, all over the world. The rice-hull contains natural silica about 20 wt.%. Therefore, a carbonized rice-hull; Rice-Hull-Silica-Carbon (RHSC) is focused as effective utilization of the discarded rice hull. In this study, test plastic helical gears were made form polyacetal copolymer filled with RHSC powder by injection molding. Test helical gears were operated on endurance test. The bulk temperature and noise of test gears were measured during gears operation. Then, the tooth damage of test gears were investigated by using optical microscope. It is clarified that difference of tooth damage by kind of test gears. Moreover, the transition of gear bulk temperature and noise during operation are investigated. Based on these results, the effect of RHSC powder is discussed. From the discussions, it seems reasonable to conclude : (1) The heat resistance of plastic gear is improved by adding the RHSC powder. (2) The fatigue life of plastic gear is improved by adding suitable amount of the RHSC powder. (3) The sound pressure level of plastic gear is reduced by adding the smaller median grain diameter of RHSC powder.

  13. Silica-Immobilized Enzyme Reactors

    Science.gov (United States)

    2007-08-01

    metal affinity binding between the ‘his- tag’ and a metal coating (cobalt) upon the agarose packing material. The peptide forms silica in situ and...the metabolism of p-nitrophenol and testosterone .[78] Similarly, β-glucuronidase was immobilized to a monolithic silica based column and used to...environmental conditions. The combination of a metal and a biocatalyst, for example, would ordinarily not be feasible due to the disparate reaction conditions

  14. Crystalline silica-induced inflammation

    OpenAIRE

    2010-01-01

    M. Tech. The persistent presence of neutrophils is associated with a wide range of inflammatory diseases. Resolution of inflammation in these diseases is also associated with the ingestion of apoptotic neutrophils by macrophages. Inflammation and apoptosis of inflammatory cells are common known features observed in the lung following exposure to crystalline silica. What is not known is how well these apoptotic cells are cleared by macrophages in the presence of crystalline silica? To inves...

  15. Prevalence of Rice Yellow Mottle Virus (RYMV) on Rice Plants ...

    African Journals Online (AJOL)

    Z. variegatus 1. 0.688. 1.037. Locust. L. migratoides. 1. 1.023. 1.037. Discussion. Viral disease due to RYMV had been a major challenge in rice production in Nigeria since 1976 when it was reported by Rossel et al. (1982). Areas of rice production in Nigeria where the virus had been detected included. Badeggi, Ibadan ...

  16. Use of heterogeneous CaO and SnO{sub 2} catalysts supported on rice husk ash to produce biodiesel; Emprego de catalisadores heterogeneos de CaO e SnO{sub 2} suportados em cinza de casca de arroz na obtencao de biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Ana Brigida [Instituto Federal do Espirito Santo, Vitoria, ES (Brazil); Silva, Paulo Roberto Nagipe da; Stumbo, Alexandre Moura, E-mail: nagipe@uenf.br [Laboratorio de Ciencias Quimicas, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ (Brazil); Freitas, Jair C.C. [Departamento de Fisica, Centro de Ciencias Exatas, Universidade Federal do Espirito Santo, Vitoria, ES (Brazil)

    2012-07-01

    Silica obtained from rice husk after acid leaching and calcination was compared to commercial silica as a catalyst support. CaO and SnO{sub 2} catalysts were prepared by impregnation and tested in the transesterification of soybean oil and the esterification of oleic acid. CaO catalysts showed basic character and were the most active for transesterification, whereas SnO{sub 2} catalysts were acid and the most effective for esterification. In both cases the performances of the catalysts prepared with rice husk ash and commercial silica were similar. These results demonstrate that rice husk is a cost-effective and environmentally-friendly source of silica that can be used as a catalyst support. (author)

  17. The Haitian Rice Tariff

    Directory of Open Access Journals (Sweden)

    Mats Lundahl

    2016-04-01

    Full Text Available Se ha argumentado que los problemas agríco-las de Haití derivan de la tarifa del arroz de a mediados de los años noventa. Antes, supues-tamente, Haití fue autosuficiente, abastecida por su producción doméstica. Después de la reducción, el mercado haitiano se inundó en importaciones de arroz barato de los EEUU, lo cual despojó a los campesinos de sus fincas, convirtiendolos en migrantes internos, hacia los empleos de bajo pago de las ciudades. El artículo rechaza ese argumento y demuestra que es falso. La malnutrición fue un fenómeno extendido en Haití mucho antes de la reducción de la tarifa del arroz, la cual tampoco tuvo un gran impacto en la importación y la producción doméstica del arroz. Lo que sí impulsó el aumento de las importaciones fue el crecimiento de la población. También el artículo argumenta que un aumento de la tarifa del arroz no solucionará el problema de la alimentación que sufre Haití. English: It has been argued that Haiti’s agricultural problems derive from the reduction of the rice tariff in the mid-1990s. Before that Haiti was allegedly able to meet its food needs by domestic production. After the reduction the Haitian market was swamped by imports of cheap American rice which drove the farmers off their lands and forced them to migrate to low-wage industrial jobs in the cities. The article demonstrates that the argument is false. Malnutrition was widespread in Haiti long before the rice tariff reduction, and the latter did not have much of an impact on rice imports and domestic production. Instead, the main driving force behind imports appears to be population growth. It is also shown that an increase of the rice tariff will not solve Haiti’s food problem.

  18. Solid silica nanoparticles: applications in molecular imaging.

    Science.gov (United States)

    Shirshahi, Vahid; Soltani, Madjid

    2015-01-01

    Silica and silica-based nanoparticles have been widely used for therapeutic and diagnostic applications in cancer mainly through delivery of drugs, genes and contrast agents. Development of synthesis methods has provided the possibility of fabricating silica nanoparticles with different sizes in nanometer ranges as well as silica-based multimodal nanoparticles with many innovative properties and intriguing applications in biomedicine. The surface of silica particles facilitates different methods of surface modifications and allows conjugation of various biomolecules such as proteins and nucleic acids. In this review, different methods of fabrication of silica and silica-based nanoparticles, their surface modification and the application of these nanoparticles in molecular imaging are discussed. Overall, the aim of this review is to address the development of silica and silica-based multifunctional nanoparticles that are introduced mainly for molecular imaging applications using optical, magnetic (MRI), X-ray (computed tomography) and multimodal imaging techniques. Copyright © 2014 John Wiley & Sons, Ltd.

  19. Hydrothermal Synthesis of High Crystalline Silicalite from Rice Husk Ash

    Directory of Open Access Journals (Sweden)

    Chaiwat Kongmanklang

    2015-01-01

    Full Text Available The objective of this research work was to evaluate the hydrothermal synthesis of silicalite with high crystallinity within a small particle size. The current study focused on investigating the effects of silica sources such as rice husk ash (RHA and silica gel (SG, crystallization time, and ratios of NaOH/SiO2, H2O/NaOH, and SiO2/TPABr. The crystallinity, particle size, and morphology were characterized by FT-IR, XRD, particle size analyser, and SEM. The conclusion of the main findings indicated that the XRD patterns of these samples clearly showed a pure phase of MFI structure corresponding to FT-IR spectra with vibration mode at 550 and 1223 cm−1. The highest crystallinity was obtained at reaction time only 6 hours with the mole ratios of NaOH/SiO2, H2O/NaOH and SiO2/TPABr as 0.24, 155, and 30, respectively. When SG was used as a silica source, it was found that the particle size was smaller than that from RHA. The morphologies of all silicalite samples were coffin and cubic-like shape.

  20. Impact of volunteer rice infestation on yield and grain quality of rice.

    Science.gov (United States)

    Singh, Vijay; Burgos, Nilda R; Singh, Shilpa; Gealy, David R; Gbur, Edward E; Caicedo, Ana L

    2017-03-01

    Volunteer rice (Oryza sativa L.) grains may differ in physicochemical traits from cultivated rice, which may reduce the quality of harvested rice grain. To evaluate the effect of volunteer rice on cultivated rice, fields were surveyed in Arkansas in 2012. Cropping history that included hybrid cultivars in the previous two years (2010 and 2011) had higher volunteer rice infestation (20%) compared with fields planted previously with inbred rice (5.5%). The total grain yield of rice was reduced by 0.4% for every 1% increase in volunteer rice density. The grain quality did not change in fields planted with the same cultivar for three years. Volunteer rice density of at least 7.6% negatively impacted the head rice and when infestation reached 17.7%, it also reduced the rice grain yield. The protein and amylose contents of rice were not affected until volunteer rice infestation exceeded 30%. Crop rotation systems that include hybrid rice are expected to have higher volunteer rice infestation than systems without hybrid rice. It is predicted that, at 8% infestation, volunteer rice will start to impact head rice yield and will reduce total yield at 18% infestation. It could alter the chemical quality of rice grain at >30% infestation. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  1. Gas Separation through Bilayer Silica, the Thinnest Possible Silica Membrane.

    Science.gov (United States)

    Yao, Bowen; Mandrà, Salvatore; Curry, John O; Shaikhutdinov, Shamil; Freund, Hans-Joachim; Schrier, Joshua

    2017-12-05

    Membrane-based gas separation processes can address key challenges in energy and environment, but for many applications the permeance and selectivity of bulk membranes is insufficient for economical use. Theory and experiment indicate that permeance and selectivity can be increased by using two-dimensional materials with subnanometer pores as membranes. Motivated by experiments showing selective permeation of H2/CO mixtures through amorphous silica bilayers, here we perform a theoretical study of gas separation through silica bilayers. Using density functional theory calculations, we obtain geometries of crystalline free-standing silica bilayers (comprised of six-membered rings), as well as the seven-, eight-, and nine-membered rings that are observed in glassy silica bilayers, which arise due to Stone-Wales defects and vacancies. We then compute the potential energy barriers for gas passage through these various pore types for He, Ne, Ar, Kr, H2, N2, CO, and CO2 gases, and use the data to assess their capability for selective gas separation. Our calculations indicate that crystalline bilayer silica, which is less than a nanometer thick, can be a high-selectivity and high-permeance membrane material for 3He/4He, He/natural gas, and H2/CO separations.

  2. Red yeast rice for dysipidemia.

    Science.gov (United States)

    Shamim, Shariq; Al Badarin, Firas J; DiNicolantonio, James J; Lavie, Carl J; O'Keefe, James H

    2013-01-01

    Red yeast rice is an ancient Chinese food product that contains monacolins, chemical substances that are similar to statins in their mechanisms of action and lipid lowering properties. Several studies have found red yeast rice to be moderately effective at improving the lipid profile, particularly for lowering the low-density lipoprotein cholesterol levels. One large randomized controlled study from China found that red yeast rice significantly improved risk of major adverse cardiovascular events and overall survival in patients following myocardial infarction. Thus, red yeast rice is a potentially useful over-the-counter cholesterol-lowering agent. However, many red yeast rice formulations are non-standardized and unregulated food supplements, and there is a need for further research and regulation of production.

  3. Removal of copper (II) ion from aqueous solution using zeolite Y synthesized from rice husk ash: Equilibrium and kinetic study

    Science.gov (United States)

    Tuyen, Nguyen Thi Kim; Nhan, Do Nguyen Thanh; Nhat, Trieu Thi; An, Ngo Thanh; Long, Nguyen Quang

    2017-09-01

    Zeolite Y was synthesized from silica of rice-husk ash using hydrothermal process. The crystalline structure FAU of zeolite Y was characterized by X-ray diffraction (XRD). Surface's area of the catalyst was determined by physic-adsorption method using BET model. The zeolite was examined for possibility of Cu2+ adsorbent by an ion-exchange mechanism. Various adsorption isotherm models, such as Langmuir, Freundlich and Dubinin-Radushkevich were tested for equilibrium study. The integration method was applied to find out the possible kinetic equation of the Cu2+ adsorption on the zeolite Y which obtained from cheap and locally available rice husk ash.

  4. Non-nutritive mineral effects on rice

    Science.gov (United States)

    The study of the responses of rice to non-nutritive minerals has numerous benefits. Rice is the current model plant for genomic studies of crops and with the sequencing of the rice genome, information obtained from rice can be extended to other organisms, which has been particularly valuable regard...

  5. Pumping Iron and Silica Bodybuilding

    Science.gov (United States)

    Mcnair, H.; Brzezinski, M. A.; Krause, J. W.; Parker, C.; Brown, M.; Coale, T.; Bruland, K. W.

    2016-02-01

    The availability of dissolved iron influences the stoichiometry of nutrient uptake by diatoms. Under nutrient replete conditions diatoms consume silicic acid and nitrate in a 1:1 ratio, this ratio increases under iron stress. Using the tracers 32Si and PDMPO, the total community and group-specific silica production rates were measured along a gradient of dissolved iron in an upwelling plume off the California coast. At each station, a control (ambient silicic acid) and +20 µM silicic acid treatment were conducted with each tracer to determine whether silicic acid limitation controlled the rate of silica production. Dissolved iron was 1.3 nmol kg-1 nearshore and decreased to 0.15 nmol kg-1 offshore. Silicic acid decreased more rapidly than nitrate, it was nearly 9 µM higher in the nearshore and 7 µM lower than nitrate in the middle of the transect where the iron concentration had decreased. The rate of diatom silica production decreased in tandem with silicic acid concentration, and silica production limitation by low silicic acid was most pronounced when iron concentrations were >0.4 nmol kg-1. The composition of the diatom assemblage shifted from Chaetoceros spp. dominated nearshore to a more sparse pennate-dominated assemblage offshore. Changes in taxa-specific silica production rates will be reported based on examination of PDMPO labeled cells using confocal microscopy.

  6. Exposure to crystalline silica in abrasive blasting operations where silica and non-silica abrasives are used.

    Science.gov (United States)

    Radnoff, Diane L; Kutz, Michelle K

    2014-01-01

    Exposure to respirable crystalline silica is a hazard common to many industries in Alberta but particularly so in abrasive blasting. Alberta occupational health and safety legislation requires the consideration of silica substitutes when conducting abrasive blasting, where reasonably practicable. In this study, exposure to crystalline silica during abrasive blasting was evaluated when both silica and non-silica products were used. The crystalline silica content of non-silica abrasives was also measured. The facilities evaluated were preparing metal products for the application of coatings, so the substrate should not have had a significant contribution to worker exposure to crystalline silica. The occupational sampling results indicate that two-thirds of the workers assessed were potentially over-exposed to respirable crystalline silica. About one-third of the measurements over the exposure limit were at the work sites using silica substitutes at the time of the assessment. The use of the silica substitute, by itself, did not appear to have a large effect on the mean airborne exposure levels. There are a number of factors that may contribute to over-exposures, including the isolation of the blasting area, housekeeping, and inappropriate use of respiratory protective equipment. However, the non-silica abrasives themselves also contain silica. Bulk analysis results for non-silica abrasives commercially available in Alberta indicate that many contain crystalline silica above the legislated disclosure limit of 0.1% weight of silica per weight of product (w/w) and this information may not be accurately disclosed on the material safety data sheet for the product. The employer may still have to evaluate the potential for exposure to crystalline silica at their work site, even when silica substitutes are used. Limited tests on recycled non-silica abrasive indicated that the silica content had increased. Further study is required to evaluate the impact of product recycling

  7. Pore Water Arsenic Dynamics in Rice Paddies Under Projected Future Climates

    Science.gov (United States)

    Plaganas, M.; Wang, T.; Muehe, E. M.; Fendorf, S. E.

    2016-12-01

    Rice is one of the staple crops in the world, with 50% of the global population eating rice daily. Many rice-producing regions of the world are irrigated with groundwater contaminated with arsenic (As), and in particular South and Southeast Asia, where geogenic As is leached into the groundwater. Use of groundwater pervasively high in As leads to subsequent accumulation in paddy soils. Arsenic, a toxic metalloid, also decreases rice productivity and further jeopardizes food security. Hence, rice agriculture is concerned with its productivity in a climate change impacted future and the particular impacts of arsenic on yields. However, past studies do not address the prevalence of As in paddy soils or its fate in the rhizosphere and ultimate impact on the plant. The objective of our study was to determine changes in pore water As dynamics in the rhizosphere of rice plants grown on As-contaminated paddy soil under climate conditions projected for the end of the century. In order to address this objective, we designed greenhouse chambers with today's climate and projected climate conditions for the year 2100, specifically 5°C increase in temperature and doubled concentration of atmospheric CO2. We hypothesize that the effects of climate change with these conditions will increase the mobility of As in the rhizosphere, and thus, decrease rice growth in As-bearing paddies more than, so far, expected. We examined pore water geochemistry including pH and As concentrations, and correlate that to the height of the plants. Furthermore, the dynamics of other elements in the pore water such as carbon, iron, sulfur, manganese, and silica are further evaluated for their effects on rice growth. Arsenic will have an impact on rice production and conditions induced by future climatic conditions need to be considered for food security. Considering that climate change will decrease the global agricultural output, we should urgently consider adapting our agricultural practices to aid

  8. The rice genome project in Japan

    OpenAIRE

    Sasaki, Takuji

    1998-01-01

    Since 1991, the Rice Genome Research Program in Japan has carried out rice genomics, such as large-scale cDNA analysis, construction of a fine-scale restriction fragment length polymorphism map, and physical mapping of the rice genome with yeast artificial chromosome clones. These studies have made a great impact on research into grass genomes and made rice a model plant for other cereal crop research. Starting in 1998, the Rice Genome Research Program will step in...

  9. Thermoelectric properties and nanostructures of materials prepared from rice husk ash

    Energy Technology Data Exchange (ETDEWEB)

    Pukird, S.; Tipparach, U.; Kasian, P. [Ubon Ratchathani Univ., Ubon Ratchathani (Thailand). Dept. of Physics; Limsuwan, P. [King Mongkut' s Univ. of Technology Thonburi, Bangkok (Thailand). Dept. of Physics

    2009-07-01

    Thailand produces large amounts of agricultural residues such as rice husk and coconut shells. Rice husk is considered to be a potential source for solar grade silicon. Studies have shown that reasonably pure polycrystalline silicon can be prepared from rice husk white ash by a metallothermic reduction process. This paper reported on a study that investigated the thermoelectric properties of ceramic material prepared by mixing silica from rice husk ash and carbon obtained from coconut shell charcoal. The thermoelectric properties of the materials were examined along with their microstructures. The materials were made from burning rice husk ash and coconut shell at different temperatures and then doped with metal oxides. Pellets were heated at temperature of 700 degrees C for 1-3 hours. The voltage on both sides of the pellets was observed. The electromotive force was found when different temperatures were applied on both sides of the pellet specimens. The Seebeck coefficient was then calculated. The results showed that these materials can be used as thermoelectric devices. Scanning electron microscope (SEM) and energy dispersive X-rays (EDX) were used to investigate the source of materials and the products on the substrates. The images of SEM and EDX showed nanostructures of materials such as nanowires, nanorods and nanoparticles of the products and sources. 22 refs., 2 tabs., 9 figs.

  10. The Brazilian School Principals

    Directory of Open Access Journals (Sweden)

    Ângelo Ricardo de Souza

    2007-09-01

    Full Text Available This article discusses the policy nature of school principal, considering the thoughts of many authors about school administration and the debate about politics, power and burocracy. The study still presents a profile of Brazilian school principals with the data of Basic Education Evaluation System – SAEB, of 2003, specially comparing elements about gender, experience and formation of school principals, and aspects linked with methodology to provide/indicate the school principal and its possible democratic vocation.

  11. Brazilian Trichoptera Checklist II

    Directory of Open Access Journals (Sweden)

    Henrique Paprocki

    2014-10-01

    Full Text Available A second assessment of Brazilian Trichoptera species records is presented here. A total of 625 species were recorded for Brazil. This represents an increase of 65.34% new species recorded during the last decade. The Hydropsychidae (124 spp., followed by the Hydroptilidae (102 spp. and Polycentropodidae (97 spp., are the families with the greatest richness recorded for Brazil. The knowledge on Trichoptera biodiversity in Brazil is geographically unequal. The majority of the species is recorded for the southeastern region.

  12. BRAZILIAN NEWS PORTALS CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    Heloiza G. Herckovitz

    2011-02-01

    Full Text Available A content analysis of four Brazilian news media portals found that economic news dominated the top headlines with little attention paid to education, the environment and welfare. Other trends included a focus on local events and national news sources, reliance on few sources, mostly official ones, and a low percentage of news that fitted the concept of newsworthiness (a combination of both social significance and deviance concepts. Other findings of a study of 432 top news stories published by UOL, Estadão, iG and Terra during a 15-day period between February and March 2008 indicate that the top portions of the portals’ front pages carry news that lacks story depth, editorial branding, and multimedia applications. The results suggest that online news portals are in their infancy although Brazil has the largest online population of Latin America. This study hopes to shed light on the gatekeeping process in Brazilian news portals. Brazilian media portals have yet to become a significant editorial force able to provide knowledge about social issues and public affairs in a socially responsible fashione.

  13. Oxidative damage and photosynthetic impairment in tropical rice cultivars upon exposure to excess iron

    Directory of Open Access Journals (Sweden)

    Samuel de Souza Pinto

    2016-06-01

    Full Text Available ABSTRACT Iron plays a pivotal role in the redox reactions of photosynthesis and metabolic processes such as chlorophyll synthesis. Iron availability in waterlogged soils can reach toxic levels and promote oxidative stress. Fe toxicity is the most concerning of stresses for rice in many lowland environments around the world and may cause severe impairments in rice photosynthesis. This study aimed to investigate the extension of oxidative stress after excess Fe exposure and its effects on the photosynthesis of rice cultivars with differential sensitivity. Three Brazilian rice cultivars (EPAGRI 107, BRSMG SELETA and BR IRGA 409 were grown in Hoagland nutrient solution (pH 4.0 with two Fe-EDTA doses corresponding to excess Fe (7 mM and control (0.009 mM treatments. After just three days of excess Fe exposure, there was a significant increase in iron concentration in the shoots. The BR IRGA 409 cultivar exhibited higher Fe accumulation in its shoots, and the EPAGRI 107 cultivar recorded the lowest values, which were below the critical toxicity level, as a resistance strategy. Impairment in light energy partitioning and oxidative damage became evident before changes in stomatal resistance, chlorophyll content, maximal PSII quantum yield or visual symptoms for the most sensitive cultivar (BR IRGA 409. The photosynthesis limitations, in addition to the impairment of excess energy dissipation in rice from iron toxicity, are the results of oxidative damage.

  14. Silica Aerogel: Synthesis and Applications

    Directory of Open Access Journals (Sweden)

    Jyoti L. Gurav

    2010-01-01

    Full Text Available Silica aerogels have drawn a lot of interest both in science and technology because of their low bulk density (up to 95% of their volume is air, hydrophobicity, low thermal conductivity, high surface area, and optical transparency. Aerogels are synthesized from molecular precursors by sol-gel processing. Special drying techniques must be applied to replace the pore liquid with air while maintaining the solid network. Supercritical drying is most common; however, recently developed methods allow removal of the liquid at atmospheric pressure after chemical modification of the inner surface of the gels, leaving only a porous silica network filled with air. Therefore, by considering the surprising properties of aerogels, the present review addresses synthesis of silica aerogels by the sol-gel method, as well as drying techniques and applications in current industrial development and scientific research.

  15. Living bacteria in silica gels

    Science.gov (United States)

    Nassif, Nadine; Bouvet, Odile; Noelle Rager, Marie; Roux, Cécile; Coradin, Thibaud; Livage, Jacques

    2002-09-01

    The encapsulation of enzymes within silica gels has been extensively studied during the past decade for the design of biosensors and bioreactors. Yeast spores and bacteria have also been recently immobilized within silica gels where they retain their enzymatic activity, but the problem of the long-term viability of whole cells in an inorganic matrix has never been fully addressed. It is a real challenge for the development of sol-gel processes. Generic tests have been performed to check the viability of Escherichia coli bacteria in silica gels. Surprisingly, more bacteria remain culturable in the gel than in an aqueous suspension. The metabolic activity of the bacteria towards glycolysis decreases slowly, but half of the bacteria are still viable after one month. When confined within a mineral environment, bacteria do not form colonies. The exchange of chemical signals between isolated bacteria rather than aggregates can then be studied, a point that could be very important for 'quorum sensing'.

  16. Physisorbed Water on Silica at Mars Temperatures

    Science.gov (United States)

    Sutter, B.; Sriwatanapongse, W.; Quinn, R.; Klug, C.; Zent, A.

    2002-01-01

    The usefulness of nuclear magnetic resonance spectroscopy in probing water interactions on silica at Mars temperatures is discussed. Results indicate that two types of water occur with silica at Mars temperatures. Additional information is contained in the original extended abstract.

  17. The efficiency of biosynthesis silica nanoparticles at removal of heavy metals Cr and Cu from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Sayadi

    2017-05-01

    Full Text Available Background and Aim: Nanotechnology considered as one of the main management strategy in reducing negative effects of water pollution, which leads to treating of water inexpensive and more effective. This study aimed to investigate the removal of Cr and Cu from aqueous solutions using nano-silicate which is synthesized by rice husk. Materials and Methods: In the present study, functionalized nano-silica with rice husk was fabricated and characterized by FT-IR، TEM, SEM and XRD. The effect of adsorbent dosage, initial concentration and equilibrium of chromium and copper and contact time in removal of mentioned heavy metals were investigated. Finally, the adsorption isotherms were analyzed. Results: The silica nanoparticles had nearly spherical morphology with a uniform size of about 80 nm. However, the obtained functionalized silica nanoparticles were spherical (about 90 nm in diameter. Results showed that optimum adsorption of Cr and Cu contaminant obtained at 100 minutes, while the optimum amount of adsorbent for Cr and Cu were 125 and 100 mg respectively. The optimal concentration of Cr and Cu was 2 mg/l. The correlation coefficients of adsorption isotherms of Cr (R2Langmuir =0.9946 and Cu (R2Langmuir =0.999 showed the good agreement between the adsorption data and Langmuir model. Conclusion: The study showed that the silica nanoparticles can be produced using agricultural waste as a inexpensive and environmentally friendly method and can be used to removing of contaminants from the aquatic environment.

  18. Silica Precursors Derived From TEOS

    Science.gov (United States)

    Philipp, Warren H.

    1993-01-01

    Two high-char-yield polysiloxane polymers developed. Designated as TEOS-A and TEOS-B with silica char yields of 55% and 22%, respectively. These free-flowing polymers are Newtonium liquids instead of thick gels. Easily synthesized by controlled hydrolysis of inexpensive tetraethoxysilane (TEOS). Adhesive properties of TEOS-A suggest its use as binder for fabrication of ceramic articles from oxide powders. Less-viscous and more-fluid lower-molecular-weight TEOS-B used to infiltrate already-formed porous ceramic compacts to increase densities without effecting shrinkage. Also used as paint to coat substrate with silica, and to make highly pure silicate powders.

  19. Optothermal nonlinearity of silica aerogel

    CERN Document Server

    Braidotti, Maria Chiara; Fleming, Adam; Samuels, Michiel C; Di Falco, Andrea; Conti, Claudio

    2016-01-01

    We report on the characterization of silica aerogel thermal optical nonlinearity, obtained by z-scan technique. The results show that typical silica aerogels have nonlinear optical coefficient similar to that of glass $(\\simeq 10^{-12} $m$^2/$W), with negligible optical nonlinear absorption. The non\\-li\\-near coefficient can be increased to values in the range of $10^{-10} $m$^2/$W by embedding an absorbing dye in the aerogel. This value is one order of magnitude higher than that observed in the pure dye and in typical highly nonlinear materials like liquid crystals.

  20. Effects of Slag-Based Silicon Fertilizer on Rice Growth and Brown-Spot Resistance

    Science.gov (United States)

    Ning, Dongfeng; Song, Alin; Fan, Fenliang; Li, Zhaojun; Liang, Yongchao

    2014-01-01

    It is well documented that slag-based silicon fertilizers have beneficial effects on the growth and disease resistance of rice. However, their effects vary greatly with sources of slag and are closely related to availability of silicon (Si) in these materials. To date, few researches have been done to compare the differences in plant performance and disease resistance between different slag-based silicon fertilizers applied at the same rate of plant-available Si. In the present study both steel and iron slags were chosen to investigate their effects on rice growth and disease resistance under greenhouse conditions. Both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to examine the effects of slags on ultrastructural changes in leaves of rice naturally infected by Bipolaris oryaze, the causal agent of brown spot. The results showed that both slag-based Si fertilizers tested significantly increased rice growth and yield, but decreased brown spot incidence, with steel slag showing a stronger effect than iron slag. The results of SEM analysis showed that application of slags led to more pronounced cell silicification in rice leaves, more silica cells, and more pronounced and larger papilla as well. The results of TEM analysis showed that mesophyll cells of slag-untreated rice leaf were disorganized, with colonization of the fungus (Bipolaris oryzae), including chloroplast degradation and cell wall alterations. The application of slag maintained mesophyll cells relatively intact and increased the thickness of silicon layer. It can be concluded that applying slag-based fertilizer to Si-deficient paddy soil is necessary for improving both rice productivity and brown spot resistance. The immobile silicon deposited in host cell walls and papillae sites is the first physical barrier for fungal penetration, while the soluble Si in the cytoplasm enhances physiological or induced resistance to fungal colonization. PMID:25036893

  1. Against the grain: safeguarding rice from rice blast disease.

    Science.gov (United States)

    Skamnioti, Pari; Gurr, Sarah J

    2009-03-01

    Rice is the staple diet of more than three billion people. Yields must double over the next 40 years if we are to sustain the nutritional needs of the ever-expanding global population. Between 10% and 30% of the annual rice harvest is lost due to infection by the rice blast fungus Magnaporthe oryzae. Evaluation of genetic and virulence diversity of blast populations with diagnostic markers will aid disease management. We review the M. oryzae species-specific and cultivar-specific avirulence determinants and evaluate efforts towards generating durable and broad-spectrum resistance in single resistant cultivars or mixtures. We consider modern usage of fungicides and plant defence activators, assess the usefulness of biological control and categorize current approaches towards blast-tolerant genetically modified rice.

  2. Niobia-silica and silica membranes for gas separation

    NARCIS (Netherlands)

    Boffa, V.

    2008-01-01

    This thesis describes the development of ceramic membranes suitable for hydrogen separation and CO2 recovery from gaseous streams. The research work was focused on the three different parts of which gas selective ceramic membranes are composed, i.e., the microporous gas selective silica layer, the

  3. Silica coated ionic liquid templated mesoporous silica nanoparticles ...

    African Journals Online (AJOL)

    Analysis indicates that the particles obtained were in spherical shape with decreasing size as the alkyl chain length of ionic liquid increases. The materials also show increase of BET surface value as the alkyl chain length increases from the range 19 m2/g to 23 m2/g. Keywords: mesoporous silica; ionic liquid, pyridinium; ...

  4. Polyethyleneimine-loaded bimodal porous silica as low-cost and high-capacity sorbent for CO{sub 2} capture

    Energy Technology Data Exchange (ETDEWEB)

    Witoon, Thongthai, E-mail: fengttwi@ku.ac.th [National Center of Excellence for Petroleum, Petrochemicals and Advance Material, Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10900 (Thailand); Center for Advanced Studies in Nanotechnology and Its Applications in Chemical Food and Agricultural Industries, Kasetsart University, Bangkok 10900 (Thailand)

    2012-11-15

    In this work, bimodal (meso-macro) porous silicas with different mesopore diameters synthesized by using rice husk ash as a low-cost silica source and chitosan as a natural template were used as a polyethyleneimine (PEI) support for CO{sub 2} capture. Unimodal porous silica supports with equivalent mesopore diameters to bimodal porous silica supports have been prepared for purpose of comparison. Effects of different PEI contents (10, 20, 30, 40 and 50 wt%) on CO{sub 2} sorption capacity have been systematically investigated. The porous silica supports and the PEI-loaded porous silica supports were characterized by N{sub 2}-sorption analysis, scanning electron microscopy, Fourier transform infrared spectroscopy and thermal gravimetric analysis. CO{sub 2} sorption measurements of all PEI-loaded porous silica supports were performed at different adsorption temperatures (60, 75, 85, 90, 95 and 105 Degree-Sign C). At low PEI contents (10-20 wt%), the CO{sub 2} sorption of all adsorbents was found to decrease as a function of adsorption temperature, which was a characteristic of a thermodynamically-controlled regime. A transition from the thermodynamically-controlled regime to a kinetically-controlled regime was found when the PEI content was increased up to 30 wt% for PEI-loaded unimodal porous silicas and 40 wt% for PEI-loaded bimodal porous silicas. At high PEI contents (40-50 wt%), the CO{sub 2} capturing efficiency of the PEI-loaded bimodal porous silicas was found to be considerably greater than that of the PEI-loaded unimodal porous silicas, indicating that most of the amine groups of PEI molecules loaded on the unimodal porous silica supports was useless, and thus the appeared macroporosity of the bimodal porous silica supports could provide a higher effective amine density to adsorb CO{sub 2}. Highlights: Black-Right-Pointing-Pointer PEI-impregnated bimodal porous silica as low-cost sorbent for CO{sub 2} capture. Black-Right-Pointing-Pointer Macropores enhances

  5. Rice Husk Filled Polymer Composites

    National Research Council Canada - National Science Library

    Arjmandi, Reza; Hassan, Azman; Majeed, Khaliq; Zakaria, Zainoha

    2015-01-01

      Natural fibers from agricultural wastes are finding their importance in the polymer industry due to the many advantages such as their light weight, low cost and being environmentally friendly. Rice husk (RH...

  6. Red Yeast Rice: An Introduction

    Science.gov (United States)

    ... mg twice daily) in patients with previous statin intolerance . American Journal of Cardiology . 2010;105:198–204. ... to Avoid Red Yeast Rice Products Promoted on Internet as Treatments for High Cholesterol: Products Found to ...

  7. Rice vaikib salavanglaist / Tõnis Erilaid

    Index Scriptorium Estoniae

    Erilaid, Tõnis, 1943-

    2005-01-01

    Euroopasse visiidile sõitev USA välisminister Condoleezza Rice külastab Saksamaad, Rumeeniat, Ukrainat ja Belgiat. Süüdistusi CIA lennukite maandumiste ja salavanglate kohta ei olevat tal kavas kommenteerida

  8. Caracterização de cinza obtida por combustão de casca de arroz em reator de leito fluidizado Characterization of ash from combustion of rice husk in a fluidized bed reactor

    Directory of Open Access Journals (Sweden)

    Juan Daniel Martínez Angel

    2009-01-01

    Full Text Available The rice husk combustion in a bubbling and atmospheric fluidized bed reactor was investigated. This paper presents the rice husk ash characterization employing the techniques of X-ray diffraction (XRD, X-ray fluorescence (XRF, and scanning electron microscopy (SEM among others. After combustion, a rice husk ash containing 93% amorphous silica and <3% unburned char was produced. Methods usually applied to fixed bed considering external sources of energy and high reaction times were employed. Thus, the potential of this type of reactors with respect to speed, continuity and self-sufficiency energy of the process was shown.

  9. Functionalized silica materials for electrocatalysis

    Indian Academy of Sciences (India)

    Electrocatalysis is an important phenomenon which is utilized in metal–air batteries, fuel cells, electrochemical sensors, etc. ... Owing to the uniform dispersion of electrocatalysts (metal complex and/or metal nanoparticles (NPs)) on the functionalized and non-functionalized silica, an enormous increase in the redox current ...

  10. Ultimate Porous Material - silica aerogel -

    OpenAIRE

    片桐, 成人; 安達, 信泰; 太田, 敏孝

    2014-01-01

    Aerogel is an ultra-porous material derived from a gel, in which the liquid component of the gel has been replaced with air. Usually, it is prepared by a supercritical drying using carbon dioxide. In this review, we introduce how to make silica aerogel as the most typical aerogel.

  11. Bioinspired synthesis of mesoporous silicas

    NARCIS (Netherlands)

    Sun, QY; Vrieling, E G; van Santen, RA; Sommerdijk, NAJM

    Recent years have witnessed rapid growth in the number of new investigations at the interface of materials chemistry and biology. This review highlights the recent developments in the studies of protein-mediated silica biomineralization in diatoms and the "downscaling" and "upscaling" models derived

  12. Catalytic esterification via silica immobilized p-phenylenediamine and dithiooxamide solid catalysts

    Directory of Open Access Journals (Sweden)

    Thana Jaafar Al-Hasani

    2017-02-01

    Full Text Available The p-phenylenediamine (PDA and dithiooxamide (DTO were immobilized onto silica from rice husk ash (RHA using 3-chloropropyltriethoxyilane (CPTES to form a solid catalyst denoted as RHAPDA and RHADTO, respectively. BET measurements of the catalysts showed the surface area to be 145 and 9.7 m2 g−1 with an average pore diameter of 9.8 and 10.9 nm, respectively. The catalytic performance of RHAPDA and RHADTO was tested in the esterification of ethyl alcohol with acetic acid. A conversion of 48% and 69% was achieved, respectively with 100% selectivity toward ethyl acetate.

  13. Further notes on Brazilian Conidae

    NARCIS (Netherlands)

    Mol, van J.-J.; Tursch, B.; Kempf, M.

    1971-01-01

    Since the publication of a survey of brazilian Conidae (Van Moll et al., 1967) new extensive dredgings effected by one of us (M.K.) along considerable portions of the Brazilian coast have brought a rich material allowing us to add to the previous work and to correct certain opinions therein

  14. Highly asymmetric rice genomes

    Directory of Open Access Journals (Sweden)

    Chen Jian-Qun

    2007-06-01

    Full Text Available Abstract Background Individuals in the same species are assumed to share the same genomic set. However, it is not unusual to find an orthologous gene only in small subset of the species, and recent genomic studies suggest that structural rearrangements are very frequent between genomes in the same species. Two recently sequenced rice genomes Oryza sativa L. var. Nipponbare and O. sativa L. var. 93-11 provide an opportunity to systematically investigate the extent of the gene repertoire polymorphism, even though the genomic data of 93-11 derived from whole-short-gun sequencing is not yet as complete as that of Nipponbare. Results We compared gene contents and the genomic locations between two rice genomes. Our conservative estimates suggest that at least 10% of the genes in the genomes were either under presence/absence polymorphism (5.2% or asymmetrically located between genomes (4.7%. The proportion of these "asymmetric genes" varied largely among gene groups, in which disease resistance (R genes and the RLK kinase gene group had 11.6 and 7.8 times higher proportion of asymmetric genes than housekeeping genes (Myb and MADS. The significant difference in the proportion of asymmetric genes among gene groups suggests that natural selection is responsible for maintaining genomic asymmetry. On the other hand, the nucleotide diversity in 17 R genes under presence/absence polymorphism was generally low (average nucleotide diversity = 0.0051. Conclusion The genomic symmetry was disrupted by 10% of asymmetric genes, which could cause genetic variation through more unequal crossing over, because these genes had no allelic counterparts to pair and then they were free to pair with homologues at non-allelic loci, during meiosis in heterozygotes. It might be a consequence of diversifying selection that increased the structural divergence among genomes, and of purifying selection that decreased nucleotide divergence in each R gene locus.

  15. [Biotoxicology and biodynamics of silica nanoparticle].

    Science.gov (United States)

    Xue, Zhi-gang; Zhu, Shai-hong; Pan, Qian; Liang, De-sheng; Li, Yu-mei; Liu, Xiong-hao; Xia, Kun; Xia, Jia-hui

    2006-02-01

    To investigate the toxicology and biodynamics of silica nanoparticle. The silica nanoparticles were injected into mice through tail vein, and the mice were amphimixised, the urine was collected in different time, variations of pathology in organs and tissues of the mice were detected. At the same time, the silica nanoparticles' distribution in the tissues was observed through electron microscope. The silica nanoparticles were detected in all tissues and urine of the mice. The injected mice can reproduce as normal. The silica nanoparticles do not have toxicity and can be used in vivo.

  16. Silica-Coated Liposomes for Insulin Delivery

    Directory of Open Access Journals (Sweden)

    Neelam Dwivedi

    2010-01-01

    Full Text Available Liposomes coated with silica were explored as protein delivery vehicles for their enhanced stability and improved encapsulation efficiency. Insulin was encapsulated within the fluidic phosphatidylcholine lipid vesicles by thin film hydration at pH 2.5, and layer of silica was formed above lipid bilayer by acid catalysis. The presence of silica coating and encapsulated insulin was identified using confocal and electron microscopy. The native state of insulin present in the formulation was evident from Confocal Micro-Raman spectroscopy. Silica coat enhances the stability of insulin-loaded delivery vehicles. In vivo study shows that these silica coated formulations were biologically active in reducing glucose levels.

  17. Diet Quality and Adequacy of Nutrients in Preschool Children: Should Rice Fortified with Micronutrients Be Included in School Meals?

    Science.gov (United States)

    Della Lucia, Ceres M; Rodrigues, Kellen Cristina C; Rodrigues, Vivian Cristina C; Santos, Laura Luiza M; Cardoso, Leandro M; Martino, Hércia S D; Franceschini, Sylvia C C; Pinheiro-Sant'Ana, Helena Maria

    2016-05-14

    Feeding is indicative of the nutritional status of children, however micronutrient deficiency is common in this age group. We evaluated the impact of inclusion of rice (Ultra Rice(®) (UR(®))) fortified with iron, zinc, thiamin and folic acid on laboratory measurements and the nutrient intake of children. Ninety-nine preschoolers (2-6 years; 42.6% male) from two preschools participated, one of which received UR(®) added to polished rice as part of school meals (test preschool) and the other received only polished rice (control preschool). Biochemical evaluations were performed before and after four months of intervention. Feeding was assessed by direct weighing of food, complemented by 24-h recalls, and the diet was assessed by the Healthy Eating Index (HEI) adapted to the Brazilian reality. The fortified rice improved the levels of zinc (p < 0.001), thiamine (p < 0.001), folic acid (p = 0.003), mean corpuscular hemoglobin (p < 0.001) and mean corpuscular hemoglobin concentration (p < 0.001). The inadequacy percentages of thiamine, folic acid and iron were lower among preschoolers from the test preschool. This study demonstrated the effectiveness of using UR(®) on laboratory measurements of children. The inadequate intake of thiamine, folic acid and iron was also reduced, making the fortified rice an interesting strategy in school feeding programs.

  18. Diet Quality and Adequacy of Nutrients in Preschool Children: Should Rice Fortified with Micronutrients Be Included in School Meals?

    Directory of Open Access Journals (Sweden)

    Ceres M. Della Lucia

    2016-05-01

    Full Text Available Feeding is indicative of the nutritional status of children, however micronutrient deficiency is common in this age group. We evaluated the impact of inclusion of rice (Ultra Rice® (UR® fortified with iron, zinc, thiamin and folic acid on laboratory measurements and the nutrient intake of children. Ninety-nine preschoolers (2–6 years; 42.6% male from two preschools participated, one of which received UR® added to polished rice as part of school meals (test preschool and the other received only polished rice (control preschool. Biochemical evaluations were performed before and after four months of intervention. Feeding was assessed by direct weighing of food, complemented by 24-h recalls, and the diet was assessed by the Healthy Eating Index (HEI adapted to the Brazilian reality. The fortified rice improved the levels of zinc (p < 0.001, thiamine (p < 0.001, folic acid (p = 0.003, mean corpuscular hemoglobin (p < 0.001 and mean corpuscular hemoglobin concentration (p < 0.001. The inadequacy percentages of thiamine, folic acid and iron were lower among preschoolers from the test preschool. This study demonstrated the effectiveness of using UR® on laboratory measurements of children. The inadequate intake of thiamine, folic acid and iron was also reduced, making the fortified rice an interesting strategy in school feeding programs.

  19. Realistic Simulation of Rice Plant

    Directory of Open Access Journals (Sweden)

    Wei-long DING

    2011-09-01

    Full Text Available The existing research results of virtual modeling of rice plant, however, is far from perfect compared to that of other crops due to its complex structure and growth process. Techniques to visually simulate the architecture of rice plant and its growth process are presented based on the analysis of the morphological characteristics at different stages. Firstly, the simulations of geometrical shape, the bending status and the structural distortion of rice leaves are conducted. Then, by using an improved model for bending deformation, the curved patterns of panicle axis and various types of panicle branches are generated, and the spatial shape of rice panicle is therefore created. Parametric L-system is employed to generate its topological structures, and finite-state automaton is adopted to describe the development of geometrical structures. Finally, the computer visualization of three-dimensional morphologies of rice plant at both organ and individual levels is achieved. The experimental results showed that the proposed methods of modeling the three-dimensional shapes of organs and simulating the growth of rice plant are feasible and effective, and the generated three-dimensional images are realistic.

  20. Effect of silica nanoparticles and BTCA on physical properties of cotton fabrics

    Directory of Open Access Journals (Sweden)

    Gobi Nallathambi

    2011-12-01

    Full Text Available Silica nanoparticles particles were synthesized from rice hulls and characterized. The particles were found to be amorphous in nature, ranging in size from 50 to 100 nm. The concentration of silica nanoparticles, pH and curing time were taken as independent variables to design the experiment. Box-Behnken method has been used to derive the experimental plan and fifteen experiments were conducted. Regression equations have been formed with the dependent and independent variables and the results of all possible combinations have been derived. The combination of optimized concentration of BTCA and SHP were used as crosslinking agent and catalyst respectively and silica nano particles were used to enhance the physical properties of the cotton fabric. The effect of pH and curing time on physical properties were analysed by FTIR studies. By ranking method the best combination of process parameters were identified. From this study, it was observed that higher concentration of silica nanoparticles with BTCA improve the crease recovery angle and tensile strength. FTIR studies revealed that the increase of pH and curing time increases the ester carbonyl band intensity ratio.

  1. Silica binding and toxicity in alveolar macrophages.

    Science.gov (United States)

    Hamilton, Raymond F; Thakur, Sheetal A; Holian, Andrij

    2008-04-01

    Inhalation of the crystalline form of silica is associated with a variety of pathologies, from acute lung inflammation to silicosis, in addition to autoimmune disorders and cancer. Basic science investigators looking at the mechanisms involved with the earliest initiators of disease are focused on how the alveolar macrophage interacts with the inhaled silica particle and the consequences of silica-induced toxicity on the cellular level. Based on experimental results, several rationales have been developed for exactly how crystalline silica particles are toxic to the macrophage cell that is functionally responsible for clearance of the foreign particle. For example, silica is capable of producing reactive oxygen species (ROS) either directly (on the particle surface) or indirectly (produced by the cell as a response to silica), triggering cell-signaling pathways initiating cytokine release and apoptosis. With murine macrophages, reactive nitrogen species are produced in the initial respiratory burst in addition to ROS. An alternative explanation for silica toxicity includes lysosomal permeability, by which silica disrupts the normal internalization process leading to cytokine release and cell death. Still other research has focused on the cell surface receptors (collectively known as scavenger receptors) involved in silica binding and internalization. The silica-induced cytokine release and apoptosis are described as the function of receptor-mediated signaling rather than free radical damage. Current research ideas on silica toxicity and binding in the alveolar macrophage are reviewed and discussed.

  2. Dietary arsenic exposure in Brazil: The contribution of rice and beans.

    Science.gov (United States)

    Ciminelli, Virginia S T; Gasparon, Massimo; Ng, Jack C; Silva, Gabriela C; Caldeira, Claudia L

    2017-02-01

    The human health risk associated with arsenic in food in Southeast Brazil was quantified. Based on the most commonly consumed food types in the Brazilian diet, the maximum inorganic As (iAs) daily intake from food (0.255 μg kg(-1) body weight per day) is approximately 9% of the Benchmark Dose Lower Limit (BMDL0.5) of 3 μg kg(-1) body weight per day set by the World Health Organization (WHO) and Food and Agriculture Organization (FAO) Joint Expert Committee in Food Additives (JECFA). When water is included, the contribution of food to the total intake varies from 96.9% to 39.7%. Rice and beans, the main Brazilian staple food, contribute between 67 and 90% of the total As intake from food (46-79% from rice and 11-23% from beans). The substantial contribution of beans to total As food intake is reported for the first time. The broad range of As concentrations in rice and beans highlights the variable and potentially large contribution of both to As food intake in places where diet consists largely of these two food categories. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Silicon isotope fractionation between rice plants and nutrient solution and its significance to the study of the silicon cycle

    Science.gov (United States)

    Ding, T. P.; Tian, S. H.; Sun, L.; Wu, L. H.; Zhou, J. X.; Chen, Z. Y.

    2008-12-01

    The silicon isotope fractionation between rice plant and nutrient solution was studied experimentally. Rice plants were grown to maturity with the hydroponic culture in a naturally lit glasshouse. The nutrient solution was sampled for 14 times during the whole rice growth period. The rice plants were collected at various growth stages and different parts of the plants were sampled separately. The silica contents of the samples were determined by the gravimetric method and the silicon isotope compositions were measured using the SiF 4 method. In the growth process, the silicon content in the nutrient solution decreased gradually from 16 mM at starting stage to 0.1-0.2 mM at harvest and the amount of silica in single rice plant increased gradually from 0.00013 g at start to 4.329 g at harvest. Within rice plant the SiO 2 fraction in roots reduced continuously from 0.23 at the seedling stage, through 0.12 at the tiller stage, 0.05 at the jointing stage, 0.023 at the heading stage, to 0.009 at the maturity stage. Accordingly, the fraction of SiO 2 in aerial parts increased from 0.77, through 0.88, 0.95, 0.977, to 0.991 for the same stages. The silicon content in roots decreased from the jointing stage, through the heading stage, to the maturity stage, parallel to the decrease of silicon content in the nutrient solution. At the maturity stage, the silicon content increased from roots, through stem and leaves, to husks, but decreased drastically from husks to grains. These observations show that transpiration and evaporation may play an important role in silica transportation and precipitation within rice plants. It was observed that the δ30Si of the nutrient solution increased gradually from -0.1‰ at start to 1.5‰ at harvest, and the δ30Si of silicon absorbed by bulk rice plant increased gradually from -1.72‰ at start to -0.08‰ at harvest, reflecting the effect of the kinetic silicon isotope fractionation during silicon absorption by rice plants from nutrient

  4. Applications of silica supports in affinity chromatography.

    Science.gov (United States)

    Schiel, John E; Mallik, Rangan; Soman, Sony; Joseph, Krina S; Hage, David S

    2006-04-01

    The combined use of silica-based chromatographic supports with immobilized affinity ligands can be used in many preparative and analytical applications. One example is the use of silica-based affinity columns in HPLC, giving rise to a method known as high-performance affinity chromatography (HPAC). This review discusses the role that silica has played in the development of affinity chromatography and HPAC and the applications of silica in these methods. This includes a discussion of the types of ligands that have been employed with silica and the methods by which these ligands have been immobilized. Various formats have also been presented for the use of silica in affinity chromatographic methods, including assays involving direct or indirect analyte detection, on-line or off-line affinity extraction, and chiral separations. The use of silica-based affinity columns in studies of biological systems based on zonal elution and frontal analysis methods will also be considered.

  5. The Pozzolanic reaction of silica fume

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede

    2012-01-01

    Silica fume is a very important supplementary cementitious binder in High-Performance and Ultra High-Performance Concretes. Through its pozzolanic reaction the silica fume densifies the concrete micro-structure, in particular it strengthens the paste-aggregate interfacial transition zone. In the ......Silica fume is a very important supplementary cementitious binder in High-Performance and Ultra High-Performance Concretes. Through its pozzolanic reaction the silica fume densifies the concrete micro-structure, in particular it strengthens the paste-aggregate interfacial transition zone....... In the present paper different aspects of the pozzolanic reaction of silica fume are investigated. These include chemical shrinkage, isothermal heat development and strength development. Key data for these are given and compared with theoretical calculations, and based on presented measurements the energy...... of activation of the pozzolanic reaction of silica fume is estimated. The results show that the pozzolanic reaction of silica fume has notable differences from Portland cement hydration....

  6. Potential of silica bodies (phytoliths) for nanotechnology.

    Science.gov (United States)

    Neethirajan, Suresh; Gordon, Richard; Wang, Lijun

    2009-08-01

    Many plant systems accumulate silica in solid form, creating intracellular or extracellular silica bodies (phytoliths) that are essential for growth, mechanical strength, rigidity, predator and fungal defence, stiffness and cooling. Silica is an inorganic amorphous oxide formed by polymerization processes within plants. There has been much research to gain new insights into its biochemistry and to mimic biosilicification. We review the background on plant silica bodies, silica uptake mechanisms and applications, and suggest possible ways of producing plant silica bodies with new functions. Silica bodies offer complementary properties to diatoms for nanotechnology, including large-scale availability from crop wastes, lack of organic impurities (in some), microencapsulation and microcrystalline quartz with possibly unique optical properties.

  7. Effect of silica sources in nanoporous silica synthesis on releasing behavior of indigo carmine

    Directory of Open Access Journals (Sweden)

    Chanatip Samart

    2009-11-01

    Full Text Available Nanoporous silica was applied in controlled releasing experiments. Different physical properties of the nanoporous silica, related to variations of the silica sources, affected the releasing behaviour. Two different silica precursors in nanoporous silica synthesis were investigated, tetraethoxysilane and sodium silicate. The nanoporous silica, which was obtained by tetraethoxysilane, gave the highest surface area (800 m2/g and pore volume (1.2 cc/g. On the other hand, the nanoporous silica obtaining from sodium silicate showed the largest pore size (9 nm. The nanoporous silica with larger pore volume can load a higher amount of indigo carmine, which resulted in a fast release due to the large driving force between the silicaparticle and media solution. However, the releasing rate was not only affected by the pore volume, but also by the interactionbetween the silanol groups on the silica surface and molecules of indigo carmine.

  8. Effect of hydrophobic nano-silica on the thermal insulation of fibrous silica compacts

    Directory of Open Access Journals (Sweden)

    Tseng-Wen Lian

    2017-06-01

    Full Text Available The particle’s surface property plays an important role on controlling the thermal insulation performance of fibrous silica compacts. In the present study, the effect of addition of hydrophobic silica on the thermal conductivity of the fibrous silica compacts is investigated. The measurement was conducted using laser flash method and differential scanning calorimeter (DSC method. The thermal conductivity of fibrous silica compacts is only 0.042 W/m K. The addition of 5% hydrophobic silica further reduces the thermal conductivity of fibrous silica compacts to 0.033 W/m K. The thermal conductivity reaches a constant value with higher hydrophobic silica content. The flexural strength decreases with the increase of hydrophobic silica content. A compromise between the thermal insulation and strength is needed. The performance of fibrous silica compacts shows strong dependence on the surface structure of glass fibers.

  9. Grain quality of upland rice cultivars in response to cropping systems in the Brazilian tropical savanna Qualidade de grãos de cultivares de arroz de terras altas em função do sistema de cultivo na região do cerrado brasileiro

    Directory of Open Access Journals (Sweden)

    Carlos Alexandre Costa Crusciol

    2008-01-01

    Full Text Available The industrial quality of grain is an important parameter to determine the commercial value of rice and can be influenced by water availability and type of cultivar. The present study aimed to evaluate the milling yield as well as the protein and nutrient contents of polished grains originated from two upland rice cultivars grown under rainfed and sprinkler-irrigated conditions. A randomized block design was used in a split-plot arrangement with eight replicates. Plots consisted of two cropping systems (rainfed and sprinkler-irrigated with subplots consisting of two cultivars recommended for upland ecosystems (IAC 201 and Carajás. The sprinkler irrigation system increased upland rice milling (8.0% and head rice yield (23.7%, for years with hot and dry weather spells occurring during the reproductive and maturation stages. Under conditions of lower water availability, the Carajás cultivar showed a milled yield value 5.1% higher than that of cultivar IAC 201. Lower water availability provided increases in protein, N, P, Ca, Mg, Fe, and Zn contents but reductions in S and Cu in the polished grains. Cultivars IAC 201 and Carajás had similar nutrient contents in the polished grains.A qualidade industrial do grão beneficiado é parâmetro importante para determinar o valor de comercialização do arroz e pode estar relacionada com a disponibilidade hídrica e o cultivar utilizado. O trabalho teve como objetivo avaliar o rendimento de engenho e teores de nutrientes e proteínas nos grãos brunidos provenientes de dois cultivares de arroz de terras altas conduzidos sob condições de sequeiro e irrigados por aspersão. O delineamento experimental utilizado foi o de blocos ao acaso, em esquema de parcela subdividida, com oito repetições. As parcelas foram constituídas por dois sistemas de cultivo (sequeiro e irrigado por aspersão e as subparcelas por dois cultivares indicados para o ecossistema de terras altas (IAC 201 e Carajás. A irriga

  10. 7 CFR 868.310 - Grades and grade requirements for the classes Long Grain Milled Rice, Medium Grain Milled Rice...

    Science.gov (United States)

    2010-01-01

    ... and objectionable seeds (number in 500 grams) Red rice and damaged kernels (singly or combined... Grain Milled Rice, Medium Grain Milled Rice, Short Grain Milled Rice, and Mixed Milled Rice. (See also Â... Milled Rice Principles Governing Application of Standards § 868.310 Grades and grade requirements for the...

  11. Brazilian Nanotechnology Initiative

    Science.gov (United States)

    Fazzio, Adalberto

    2015-03-01

    In Brazil there is intense research activity in nanotechnology, most of these developed in universities and research institutes. The Brazilian Nanotechnology Initiative (BNI) aims to integrate government actions to promote the competitiveness of the Brazilian industry. This initiative is founded on support for research and development in the laboratories of the National Laboratories for Nanotechnology (SisNANO), starting from an improvement in infrastructure and opening of laboratories for users of academia and business, promoting interaction and transfer knowledge between academia and business. Country currently has 26 thematic networks of nanotechnology, 16 -Virtual-National Institutes of Technology, seven National- Laboratories and 18 Associate Laboratories, which comprise the SisNANO. Seeking to expand and share governance with other government actors, the Interministries Committee for Nanotechnology was set up, composed of 10 ministries, and has the task of coordinating the entire program of the Federal Government Nanotechnology.Cooperation activities are an important part of BNI. Currently Brazil has cooperation programs with U.S., China, Canada and European Union among others. Recently, Brazil decided to join the European NanoReg program where 60 research groups are joining efforts to provide protocols and standards that can help regulatory agencies and governments.

  12. Pharmacogenetics in the Brazilian population

    Directory of Open Access Journals (Sweden)

    Guilherme eSuarez-Kurtz

    2010-10-01

    Full Text Available Brazil is the 5th largest country in the world and its present population, in excess of 190 million, is highly heterogeneous, as a result of centuries of admixture between Amerindians, Europeans and Sub-Saharan Africans. The estimated individual proportions of biogeographical ancestry vary widely and continuously among Brazilians, most individuals - irrespective of self-identification as White, Brown or Black, the major categories of the Brazilian Census race/color system - having significant degrees of European and African ancestry, while a sizeable number display also Amerindian ancestry. These features have important pharmacogenetic (PGx implications: first, extrapolation of PGx data from relatively well-defined ethnic groups is clearly not applicable to the majority of Brazilians; second, the frequency distribution of polymorphisms in pharmacogenes (e.g. CYP3A5, CYP2C9, GSTM1, ABCB1, GSTM3, VKORC, etc varies continuously among Brazilians and is not captured by race/color self-identification; third, the intrinsic heterogeneity of the Brazilian population must be acknowledged in the design and interpretation of PGx studies in order to avoid spurious conclusions based on improper matching of study cohorts. The peculiarities of PGx in Brazilians are illustrated with data for different therapeutic groups, such as anticoagulants, HIV-protease inhibitors and nonsteroidal antinflammatory drugs, and the challenges and advantages created by population admixture for the study and implementation of PGx are discussed. PGx data for Amerindian groups and Brazilian-born, first generation Japanese are presented to illustrate the rich diversity of the Brazilian population. Finally, I introduce the reader to the Brazilian Pharmacogenetic Network or Refargen (www.refargen.org.br, a nationwide consortium of research groups, with the mission to provide leadership in PGx research and education in Brazil, with a population health impact.

  13. Dietary exposure of Brazilian consumers to dithiocarbamate pesticides--a probabilistic approach.

    Science.gov (United States)

    Caldas, E D; Tressou, J; Boon, P E

    2006-09-01

    A probabilistic estimation of the exposure of the Brazilian population to the dithiocarbamate pesticides was performed using the Monte Carlo Risk Assessment program (MCRA 3.5). Residue data, as CS2, for 3821 samples were obtained from the Brazilian national monitoring program on pesticide residues and from the monitoring program conducted in the Distrito Federal on rice, beans and nine fruits and vegetables. Food consumption data were obtained from a Brazilian household budget survey conducted between 2002 and 2003. Processing factors for washing, peeling or cooking were applied to the residues found in the crops. Daily intakes at the highest percentiles for the general population reached a maximum of 2.0 microg CS2/kg body weight per day (upper band of the 95% confidence interval at P99.99). Tomato, rice, apple and lettuce were the commodities which contributed most to the intake. Based on the registered uses and the toxicological profile of dithiocarbamates, the risk from exposure was evaluated assuming that all residues came from the use of ethylene-bis-dithiocarbamate (EBDC) or that a fraction of it came from the use of propineb. For this last scenario, a cumulative risk assessment was conducted. In the first scenario, the highest intake reached up to 11.9% EBDC ADI for the general population and up to 31.1% ADI for children. When 30% of the residues were considered as coming from propineb use, the values were 15.2% and 39.7% ADI, respectively.

  14. Silicosis in silica flour workers.

    Science.gov (United States)

    Banks, D E; Morring, K L; Boehlecke, B A; Althouse, R B; Merchant, J A

    1981-10-01

    In July 1979, the health of 86 current and ex-workers at 2 silica mining and milling operations in southern Illinois was examined using a respiratory questionnaire, spirometry, and chest radiographs. None of 25 current workers with less than 1 yr of exposure to silica dust had radiographic evidence of silicosis. For 61 current workers and ex-workers with 1 or more yr of exposure, chest radiographs showed 16 (26%) with simple silicosis and 7 (11%) with progressive massive fibrosis. Of these 23, 8 with simple silicosis and 3 with progressive massive fibrosis began work after the first Mine Safety and Health Administration inspection in 1973. These data and a review of federal dust inspection results between 1973 and 1979 showed that these cases of silicosis could have been prevented by effecting compliance with the existing dust standard.

  15. The rise of Brazilian agriculture

    DEFF Research Database (Denmark)

    Jensen, Hans Grinsted; Vink, Nick; Sandrey, Ron

    2014-01-01

    The purpose of this article is to explore some of the possible lessons for South African agriculture from the Brazilian experience. To this end, the article discusses the performance of Brazilian agriculture in terms of land and labour use, production, and exports. This is followed by aspects...... of Brazilian agricultural policies, namely farmer support, the research and technology transfer system and land issues. The implications for South African agriculture can be summarized as the recognition that history, geography, the development path and agricultural policies all matter. The article...... then identifies five important lessons for agricultural development in South Africa....

  16. Elemental composition of Malawian rice.

    Science.gov (United States)

    Joy, Edward J M; Louise Ander, E; Broadley, Martin R; Young, Scott D; Chilimba, Allan D C; Hamilton, Elliott M; Watts, Michael J

    2017-08-01

    Widespread potential dietary deficiencies of calcium (Ca), iron (Fe), iodine (I), selenium (Se) and zinc (Zn) have been identified in Malawi. Several deficiencies are likely to be compounded by high phytic acid (PA) consumption. Rice (Oryza sativa) is commonly consumed in some Malawian populations, and its mineral micronutrient content is important for food security. The considerable irrigation requirements and flooded conditions of paddy soils can also introduce or mobilise potentially toxic elements including arsenic (As), cadmium (Cd) and lead (Pb). The aim of this study was to determine the mineral composition of rice sampled from farmers' fields and markets in Malawi. Rice was sampled from 18 extension planning areas across Malawi with 21 white (i.e. polished) and 33 brown samples collected. Elemental composition was determined by inductively coupled plasma-mass spectrometry (ICP-MS). Arsenic speciation was performed using high-performance liquid chromatography (HPLC)-ICP-MS. Concentration of PA was determined using a PA-total phosphorus assay. Median total concentrations (mg kg-1, dry weight) of elements important for human nutrition in brown and white rice, respectively, were: Ca = 66.5 and 37.8; Cu = 3.65 and 2.49; Fe = 22.1 and 7.2; I = 0.006 and elements (mg kg-1, dry weight) in brown and white rice samples, respectively, were: As = 0.030 and 0.006; Cd  ≤ 0.002 and 0.006; Pb = 0.008 and 0.008. Approximately 95 % of As was found to be inorganic As, where this could be quantified. Malawian rice, like the more widely consumed staple grain maize, contains inadequate Ca, I, Se or Zn to meet dietary requirements. Biofortification strategies could significantly increase Se and Zn concentrations and require further investigation. Concentrations of Fe in rice grain varied greatly, and this was likely due to contamination of rice samples with soil. Risk of As, Cd or Pb toxicity due to rice consumption in Malawi appears to be minimal.

  17. Chemical substitution in silica polymorph

    Science.gov (United States)

    Smith, J. V.; Steele, I. M.

    1984-01-01

    Ion and electron probe analyses are presented for trace elements (Al, Na, K, Li, Ti) in quartz, tridymite, cristobalite and melanophlogite. Quartz and melanophlogite show low levels of trace elements relative to tridymite and cristobalite. The previously determined alpha-beta inversion temperature decreases as the Al content of quartz increases. For all silica polymorphs, Al is greater than or equal to Na + K + Li on an atom basis, with the excess Al probably balanced by H.

  18. Brazilian Space Weather Program

    Science.gov (United States)

    Padilha, Antonio; Takahashi, Hisao; de Paula, Eurico; Sawant, Hanumant; de Campos Velho, Haroldo; Vitorello, Icaro; Costa, Joaquim; Souza, Jonas; Cecatto, José; Mendes, Odim; Gonzalez Alarcon, Walter Demétrio

    A space weather program is being initiated at the Brazilian National Institute for Space Research (INPE) to study events from their initiation on the sun to their impacts on the earth, including their effects on space-based and ground-based technological systems. The program is built on existing capabilities at INPE, which include scientists with a long tradition and excellence in the observation, analysis and modeling of solar and solar-terrestrial phenomena and an array of geophysical instruments that spans all over the Brazilian territory from the north to south of the magnetic dip equator. Available sensors include solar radio frequency receivers and telescopes, optical instruments and solar imagers, GNSS receivers, ionosondes, radars, allsky imagers, magnetometers and cosmic ray detectors. In the equatorial region, ionosphere and thermosphere constitute a coupled system with electrodynamical and plasma physical processes being responsible for a variety of peculiar phenomena. The most important of them are the equatorial electrojet current system and its instabilities, the equatorial ionization anomaly, and the plasma instabilities/irregularities of the night-time ionosphere (associated with the plasma bubble events). In addition, space weather events modify the equatorial ionosphere in a complex and up to now unpredictable manner. Consequently, a main focus of the program will be on monitoring the low, middle and upper atmosphere phenomena and developing a predictive model of the equatorial ionosphere through data assimilation, that could help to mitigate against the deleterious effects on radio communications and navigation systems. The technological, economic and social importance of such activities was recognized by the Brazilian government and a proposal for funding was approved for the period 2008-2011. New ground instruments will be installed during this period allowing us to extend our current capability to provide space weather observations, accurate

  19. Red Yeast Rice

    Directory of Open Access Journals (Sweden)

    Thu Nguyen

    2017-03-01

    Full Text Available Red yeast rice (RYR, produced by the fermentation of the Monascus purpureus mold, has been used for a long time in Asian cuisine and traditional medicine. It consists of multiple bioactive substances, including monacolins, which potentially can be used as a nutraceutical. Monacolin K, which is chemically identical to lovastatin, has been recognized as responsible for the cholesterolreducing effect of this compound. While the European Food Safety Authority maintains that the use of monacolin K from RYR preparations of at least 10 mg can produce a normal blood cholesterol level, the United States Food and Drug Administration considers monacolin K, due to its similarity with lovastatin, an unapproved drug, and therefore marketing of products that label the monacolin content is prohibited. This mini-review summarizes the benefit of RYR in hyperlipidemia, maintains RYR use as a food, and addresses the importance of regulation regarding RYR and the need for clinical data and clear label information for consumers with reference to a toxin-free, nonaugmented, standardized amount of monacolins.

  20. Red Yeast Rice.

    Science.gov (United States)

    Nguyen, Thu; Karl, Mitchell; Santini, Antonello

    2017-03-01

    Red yeast rice (RYR), produced by the fermentation of the Monascus purpureus mold, has been used for a long time in Asian cuisine and traditional medicine. It consists of multiple bioactive substances, including monacolins, which potentially can be used as a nutraceutical. Monacolin K, which is chemically identical to lovastatin, has been recognized as responsible for the cholesterolreducing effect of this compound. While the European Food Safety Authority maintains that the use of monacolin K from RYR preparations of at least 10 mg can produce a normal blood cholesterol level, the United States Food and Drug Administration considers monacolin K, due to its similarity with lovastatin, an unapproved drug, and therefore marketing of products that label the monacolin content is prohibited. This mini-review summarizes the benefit of RYR in hyperlipidemia, maintains RYR use as a food, and addresses the importance of regulation regarding RYR and the need for clinical data and clear label information for consumers with reference to a toxin-free, nonaugmented, standardized amount of monacolins.

  1. Arsenic in rice: A cause for concern

    DEFF Research Database (Denmark)

    Hojsak, Iva; Braegger, Christian; Bronsky, Jiri

    2015-01-01

    Inorganic arsenic intake is likely to affect long-term health. High concentrations are found in some rice-based foods and drinks widely used in infants and young children. In order to reduce exposure we recommend avoidance of rice drinks for infants and young children. For all rice products, strict...

  2. implications for smallholder rice production in

    African Journals Online (AJOL)

    backdrop of macro-economic policy framework of free market where trade liberalization allows for the free flow of goods and services will severe implication for the rice industry. This paper discusses trade liberalization policy effects on rice imports in. Ghana and the implications for smallholder rice. farmers in North-.

  3. 21 CFR 137.350 - Enriched rice.

    Science.gov (United States)

    2010-04-01

    ... 1,000 milligrams of calcium (Ca). Calcium carbonate derived from the use of this substance in milling rice, when present in quantities that furnish less than 500 milligrams of calcium (Ca) per pound... enriched rice unless such enriched rice is labeled to show it contains the optional ingredient calcium...

  4. Structural and functional analysis of rice genome

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 83; Issue 1. Structural and functional analysis of rice genome ... Abstract. Rice is an excellent system for plant genomics as it represents a modest size genome of 430 Mb. It feeds more than half the population of the world. Draft sequences of the rice genome, derived by ...

  5. Arsenic in rice: a cause for concern

    NARCIS (Netherlands)

    Hojsak, Iva; Braegger, Christian; Bronsky, Jiri; Campoy, Cristina; Colomb, Virginie; Decsi, Tamas; Domellöf, Magnus; Fewtrell, Mary; Mis, Nataša Fidler; Mihatsch, Walter; Molgaard, Christian; van Goudoever, Johannes

    2015-01-01

    Inorganic arsenic intake is likely to affect long-term health. High concentrations are found in some rice-based foods and drinks widely used in infants and young children. In order to reduce exposure, we recommend avoidance of rice drinks for infants and young children. For all of the rice products,

  6. Nanostructured silicon nitride from wheat and rice husks

    Energy Technology Data Exchange (ETDEWEB)

    Qadri, S. B.; Rath, B. B.; Gorzkowski, E. P.; Wollmershauser, J. A.; Feng, C. R. [Materials Science and Component Technology Directorate, Naval Research Laboratory, Washington, D.C. 20375 (United States)

    2016-04-07

    Nanoparticles, submicron-diameter tubes, and rods of Si{sub 3}N{sub 4} were synthesized from the thermal treatment of wheat and rice husks at temperatures at and above 1300 °C in a nitrogen atmosphere. The whole pattern Rietveld analysis of the observed diffraction data from treatments at 1300 °C showed the formation of only hexagonal α-phase of Si{sub 3}N{sub 4} with an R-factor of 1%, whereas samples treated at 1400 °C and above showed both α- and β-phases with an R-factor of 2%. Transmission electron microscopy showed the presence of tubes, rods, and nanoparticles of Si{sub 3}N{sub 4}. In a two-step process, where pure SiC was produced first from rice or wheat husk in an argon atmosphere and subsequently treated in a nitrogen atmosphere at 1450 °C, a nanostructured composite material having α- and β-phases of Si{sub 3}N{sub 4} combined with cubic phase of SiC was formed. The thermodynamics of the formation of silicon nitride is discussed in terms of the solid state reaction between organic matter (silica content), which is inherently present in the wheat and rice husks, with the nitrogen from the furnace atmosphere. Nanostructures of silicon nitride formed by a single direct reaction or their composites with SiC formed in a two-step process of agricultural byproducts provide an uncomplicated sustainable synthesis route for silicon nitride used in mechanical, biotechnology, and electro-optic nanotechnology applications.

  7. Late Cretaceous origin of the rice tribe provides evidence for early diversification in Poaceae.

    Science.gov (United States)

    Prasad, V; Strömberg, C A E; Leaché, A D; Samant, B; Patnaik, R; Tang, L; Mohabey, D M; Ge, S; Sahni, A

    2011-09-20

    Rice and its relatives are a focal point in agricultural and evolutionary science, but a paucity of fossils has obscured their deep-time history. Previously described cuticles with silica bodies (phytoliths) from the Late Cretaceous period (67-65 Ma) of India indicate that, by the latest Cretaceous, the grass family (Poaceae) consisted of members of the modern subclades PACMAD (Panicoideae-Aristidoideae-Chloridoideae-Micrairoideae-Arundinoideae-Danthonioideae) and BEP (Bambusoideae-Ehrhartoideae-Pooideae), including a taxon with proposed affinities to Ehrhartoideae. Here we describe additional fossils and show that, based on phylogenetic analyses that combine molecular genetic data and epidermal and phytolith features across Poaceae, these can be assigned to the rice tribe, Oryzeae, of grass subfamily Ehrhartoideae. The new Oryzeae fossils suggest substantial diversification within Ehrhartoideae by the Late Cretaceous, pushing back the time of origin of Poaceae as a whole. These results, therefore, necessitate a re-evaluation of current models for grass evolution and palaeobiogeography.

  8. Facile catalytic combustion of rice husk and burning temperature dependence of the ashes.

    Science.gov (United States)

    Xiong, Liangming; Sekiya, Edson H; Wada, Shigetaka; Saito, Kazuya

    2009-11-01

    In this work, it was discovered and demonstrated that the combustion of rice husk is a catalytic process by the thermoanalytical technique. The catalyst involves the oxides of such transition metals as Mn, Fe, and Cu, which are mainly formed in the initial stage of rice husk combustion and remain in the rice husk ash as an impurity. Mn(2+) ions of various concentrations were reloaded into the HCl-washed husk for cocombustion. As a result, the complete combustion temperature of the husk was decreased exponentially depending on the Mn(2+) concentration. By the facile Mn loading technique using a 0.5 M solution, the combustion temperature can be decreased by approximately 100 degrees C, and the resulting ashes themselves can be a good catalyst in the complete combustion of many other organic compounds. The physicochemical properties and amorphous structure of the ashes from both the raw and HCl-washed husks were found to be strongly dependent on the burning temperature. A decreased complete rice husk combustion temperature can be beneficial in preparing porous amorphous silica with high surface area, high densification, and small Si-O-Si band angles.

  9. brazilian subsidiaries of multinationals

    Directory of Open Access Journals (Sweden)

    Felipe Mendes Borini

    2012-01-01

    Full Text Available The theme of corporate social responsibility (CSR has not been widely examined in the context of multinationals. This dearth is even greater with respect to subsidiaries, particularly the subject of reverse transfer of practices, that is, the transfer of practices developed in subsidiaries back to the parent company. Because of this theoretical gap, the present article investigates the factors involved on reverse transfer of CSR practices. The research hypotheses test the importance of developing nonlocation-bound capabilities, of integration between subsidiaries and parent and of institutional distance. The data were obtained by a survey of the main foreign subsidiaries in Brazil. All told, we analyzed 150 Brazilian subsidiaries of multinationals, by applying multiple linear regression. The results indicate that the reverse transfer of CSR depends on the development of nonlocation-bound capabilities of the subsidiaries and integration between the parent company and its foreign subsidiaries.

  10. Brazilian Eratosthenes Project

    Science.gov (United States)

    Langhi, R.; Vilaça, J.

    2014-10-01

    The objective of Brazilian Eratosthenes Project is the development and application of teaching training actions according the ``docent autonomy" concept to basic Astronomy Education. Argentina coordinates the project in South America, but Brazil works in this project since 2010 with the theme ``Projeto Eratóstenes Brasil" in the homepage: http://sites.google.com/site/projetoerato. Two schools measure a sticks shadow and communicate their results. After, they calculate an average radius of Earth. The stick (gnomon) should stay in vertical position in the leveled ground. Since 2010, the project received hundreds of Brazilian schools with different experiments that were constructed with autonomy, because our site doesn't show some itinerary pre-ready to elaborate the experiments. To collect data for our research, we will use interviews via Skype with the teachers. These data are useful to researches about Science Education area and the Teaching Formation. Teaching professional practice could change and we see modifications in the teachers work, what depends of their realities and context. This project intents to respect the docent autonomy. This autonomy to responsible modifications during continued formation is called ``activist formative model" according Langhi & Nardi (Educação em Astronomia: repensando a formação de professores. São Paulo: Escrituras Editora, 2012). This project discusses about researches in Astronomy Education - still extreme rare in Brazil, when we compare with other areas in Science Education. We believe that actions like this could motivate the students to learn more Astronomy. Furthermore, this national action can be a rich source of data to investigations about teaching formation and scientific divulgation.

  11. Non-occupational exposure to silica dust.

    Science.gov (United States)

    Bhagia, L J

    2012-09-01

    Occupational exposure to silica occurs at workplaces in factories like quartz crushing facilities (silica flour milling), agate, ceramic, slate pencil, glass, stone quarries and mines, etc., Non-occupational exposure to silica dust can be from industrial sources in the vicinity of the industry as well as non-industrial sources. Recently, public concern regarding non-occupational or ambient exposure to crystalline silica has emerged making it important to gather information available on non-occupational exposures to silica dust and non-occupational silicosis. This paper reviews various non-occupational exposures reported in literature including some studies by the author. Methodology used in assessment of non-occupational exposures, standards for non-occupational exposures to silica dust and indirect estimation of cumulative risk % are also discussed.

  12. Toxicity assessment of silica nanoparticles, functionalised silica nanoparticles, and HASE-grafted silica nanoparticles.

    Science.gov (United States)

    Clément, Laura; Zenerino, Arnaud; Hurel, Charlotte; Amigoni, Sonia; Taffin de Givenchy, Elisabeth; Guittard, Frédéric; Marmier, Nicolas

    2013-04-15

    Numerous nanomaterials have recently been developed, and numerous practical applications have been found in water treatment, medicine, cosmetics, and engineering. Associative polymers, such as hydrophobically modified alkali-soluble emulsion (HASE) systems are involved in several applications and have been extensively studied due to their ability to form three-dimensional networked gels. However, the data on the potential environmental effects of this polymers are scarce. The aim of this study is to assess the effect of functionalisation of silica nanoparticles, and coupling of functionalised silica nanoparticles to the associative polymer HASE on their toxicity. Thus, acute and chronic toxicity tests included a modified acute test (72 h) using daphnies, algae, and plants as model organisms. Gradient of toxicity varied with the tested organisms. Our results revealed that the functionalised nanoparticules and NP grafted polymer cause a global decrease in toxicity compared to commercial nanoparticule and HASE polymer. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. INNOVATION IN BRAZILIAN SMALL COMPANIES

    Directory of Open Access Journals (Sweden)

    Tonny Kerley de Alencar Rodrigues

    2015-03-01

    Full Text Available This study aims to identify the interfaces and boundaries of innovation orientation of Brazilian MSEs because despite the importance of innovation for Brazilian MSEs, a thorough analysis of such initiatives in Brazil still has not actually happened. The search was developed from a quantitative approach, of applied nature and descriptive. For that a structured questionnaire was used where were interviewed 700 MSEs using a probabilistic sampling. The study offers two important conclusions. The challenges for innovation can be perceived along three dimensions: design innovation, the implementation of innovation and functional area of innovation. And the data confirms that small Brazilian companies generally have difficulties to sell their innovations. The study offers two important conclusions. The challenges for innovation can be perceived along three dimensions: design innovation, the implementation of innovation and functional area of innovation. And the data confirms that small Brazilian companies generally have difficulties to sell their innovations.

  14. Ultrasonic and conventional synthesis of NaA zeolite from rice husk ash

    Science.gov (United States)

    Farías, T.; de Ménorval, LC; Picazo, O.; Jordán, R.

    2017-01-01

    In the present work, a simple synthetic route for the production of single phase NaA zeolite is demonstrated. Rice husk ash (RHA) as alternative silica source was employed for the synthesis by conventional hydrothermal and non-conventional ultrasound methods. The zeolite was also synthesized using commercially available silicate for comparison. The effect of the reaction time (2, 4 and 6 h) at a fixed temperature of 70 °C was investigated. The elemental, structural and morphological characterization of the ashes and the synthesized zeolites was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and thermogravimetric analysis (TG/DSC).

  15. Silica binding and toxicity in alveolar macrophages

    OpenAIRE

    Hamilton, Raymond F.; Thakur, Sheetal A.; Holian, Andrij

    2007-01-01

    Inhalation of the crystalline form of silica is associated with a variety of pathologies from acute lung inflammation to silicosis, in addition to autoimmune disorders and cancer. Basic science researchers looking at the mechanisms involved with the earliest initiators of disease are focused on how the alveolar macrophage (AM) interacts with the inhaled silica particle and the consequences of silica-induced toxicity on the cellular level. Based on experimental results, several rationales have...

  16. Iron biofortification of Myanmar rice

    Directory of Open Access Journals (Sweden)

    May Sann Aung

    2013-05-01

    Full Text Available Iron (Fe deficiency causes elevates human mortality rates, especially in developing countries. In Myanmar, the prevalence of Fe-deficient anemia in children and pregnant women are 75% and 71%, respectively. Myanmar people have one of the highest per capita rice consumption rates globally. Consequently, production of Fe-biofortified rice would likely contribute to solving the Fe-deficiency problem in this human population. To produce Fe-biofortified Myanmar rice by transgenic methods, we first analyzed callus induction and regeneration efficiencies in 15 varieties that are presently popular because of their high yields and/or qualities. Callus formation and regeneration efficiency in each variety was strongly influenced by types of culture media containing a range of 2,4-dichlorophenoxyacetic acid concentrations. The Paw San Yin variety, which has a high Fe content in polished seeds, performed well in callus induction and regeneration trials. Thus, we transformed this variety using a gene expression cassette that enhanced Fe transport within rice plants through overexpression of the nicotianamine synthase gene HvNAS1, Fe flow to the endosperm through the Fe(II-nicotianamine transporter gene OsYSL2, and Fe accumulation in endosperm by the Fe storage protein gene SoyferH2. A line with a transgene insertion was successfully obtained. Enhanced expressions of the introduced genes OsYSL2, HvNAS1, and SoyferH2 occurred in immature T2 seeds. The transformants accumulated 3.4-fold higher Fe concentrations, and also 1.3-fold higher zinc concentrations in T2 polished seeds compared to levels in non-transgenic rice. This Fe-biofortified rice has the potential to reduce Fe-deficiency anemia in millions of Myanmar people without changing food habits and without introducing additional costs.

  17. Innovation in brazilian small companies

    OpenAIRE

    Tonny Kerley de Alencar Rodrigues; Átila de Melo Lira; Irenilza Alencar Naas

    2015-01-01

    This study aims to identify the interfaces and boundaries of innovation orientation of Brazilian MSEs because despite the importance of innovation for Brazilian MSEs, a thorough analysis of such initiatives in Brazil still has not actually happened. The search was developed from a quantitative approach, of applied nature and descriptive. For that a structured questionnaire was used where were interviewed 700 MSEs using a probabilistic sampling. The study offers two important conclusions. The ...

  18. Characterization, treatment and utilization of rice husk ash in production processes of the industrial branch; Caracterizacao, tratamento e aproveitamento das cinzas da casca do arroz em processos produtivos do ramo industrial

    Energy Technology Data Exchange (ETDEWEB)

    Stracke, Marcelo Paulo; Schmidt, Julia Isabel; Steffen, Ana Cristina; Sokolovicz, Boris; Kieckow, Flavio, E-mail: stracke@santoangelo.uri.br [Universidade Regional Integrada do Alto Uruguai e das Missoes (URI), Santo Angelo, RS (Brazil)

    2016-07-01

    The rice husk ash (CCA) is a black powder rich in silica (contents above 90%) with many industrial applications. The ash was obtained from a rice processing industry in the state of Rio Grande do Sul. In this work the purpose is to characterize the rice husk ash and eliminate the residual carbon by methods such as acid leaching. The white ash is obtained by a chemical process followed by heating between 600 and 800 °C. The results were analyzed in DR-X, TGA and DSC. The DR-X analysis showed that the samples present high levels of silica in the crystalline form of quartz, cristobalite and tridymite. The white ash was obtained with high purity and presented a good result in the manufacture of paints. (author)

  19. Thermal, structural and morphological properties of High Density Polyethylene matrix composites reinforced with submicron agro silica particles and Titania particles

    Directory of Open Access Journals (Sweden)

    Oluyemi O. Daramola

    2017-07-01

    Full Text Available HDPE—based composites samples filled with 2, 4, 6, 8 and 10 wt.% submicron agro-waste silica particles extracted from rice husk ash (RHA at constant 0.3 wt.% Titania loading were prepared using rapra single screw extruder at temperature of 200–230 °C. The extrudates were compressed with a laboratory carver press at a temperature of 230 °C for 10 min under applied pressure of 0.2 kPa and water cooled at 20 °C min−1. Thermal, structural and morphological properties of the composites were studied. The results of the thermogravimetric analysis (TGA revealed that the composites with 10 wt.% SiO2 have the best maximum thermal degradation temperature of 438.73 °C. The crystal structure of neat HDPE, and the siliceous composites developed revealed two obvious diffractive peaks of about 21.3° and 23.7° corresponding to typical crystal plane (1 1 0 and (2 0 0 of orthorhombic phase respectively. The diffractive peaks do not shift with the addition of silica particles; this clearly indicates that the addition of silica particles did not exert much effect on the crystalline structure of HDPE. There is no much difference in the interplanar distance (d-value. Lamellar thickness (L of HDPE increases with the addition of silica particles, which implies that silica particles aid the formation of more perfect crystals. Scanning electron microscopy studies indicated that there were chains inter diffusion and entanglement between HDPE matrix and the silica particles at lower weight fraction (2–4 wt.% of submicron silica particles which resulted into homogeneous dispersion of the particles within the matrix.

  20. Nanoporous silica membranes with high hydrothermal stability

    DEFF Research Database (Denmark)

    Boffa, Vittorio; Magnacca, Giualiana; Yue, Yuanzheng

    Despite the use of sol-gel derived nanoporous silica membranes in substitution of traditional separation processes is expected leading to vast energy savings, their intrinsic poor steam-stability hampers their application at an industrial level. Transition metal ions can be used as dopant...... to improve the stability of nanoporous silica structure. This work is a quantitative study on the impact of type and concentration of transition metal ions on the microporous structure and stability of amorphous silica-based membranes, which provides information on how to design chemical compositions...... and synthetic paths for the fabrication of silica-based membranes with a well accessible and highly stabile nanoporous structure...

  1. Practical Hydrogen Loading of Air Silica Fibres

    DEFF Research Database (Denmark)

    Sørensen, Henrik Rokkjær; Jensen, Jesper Bevensee; Jensen, Jesper Bo Damm

    2005-01-01

    A method for hydrogen-loading air-silica optical fibres has been developed allowing out-diffusion times comparable to standard step-index fibres. Examples of the first grating written in Ge-doped air-silica fibres using a 266nm UV-laser are shown.......A method for hydrogen-loading air-silica optical fibres has been developed allowing out-diffusion times comparable to standard step-index fibres. Examples of the first grating written in Ge-doped air-silica fibres using a 266nm UV-laser are shown....

  2. Cellular membrane trafficking of mesoporous silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Fang, I-Ju [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    This dissertation mainly focuses on the investigation of the cellular membrane trafficking of mesoporous silica nanoparticles. We are interested in the study of endocytosis and exocytosis behaviors of mesoporous silica nanoparticles with desired surface functionality. The relationship between mesoporous silica nanoparticles and membrane trafficking of cells, either cancerous cells or normal cells was examined. Since mesoporous silica nanoparticles were applied in many drug delivery cases, the endocytotic efficiency of mesoporous silica nanoparticles needs to be investigated in more details in order to design the cellular drug delivery system in the controlled way. It is well known that cells can engulf some molecules outside of the cells through a receptor-ligand associated endocytosis. We are interested to determine if those biomolecules binding to cell surface receptors can be utilized on mesoporous silica nanoparticle materials to improve the uptake efficiency or govern the mechanism of endocytosis of mesoporous silica nanoparticles. Arginine-glycine-aspartate (RGD) is a small peptide recognized by cell integrin receptors and it was reported that avidin internalization was highly promoted by tumor lectin. Both RGD and avidin were linked to the surface of mesoporous silica nanoparticle materials to investigate the effect of receptor-associated biomolecule on cellular endocytosis efficiency. The effect of ligand types, ligand conformation and ligand density were discussed in Chapter 2 and 3. Furthermore, the exocytosis of mesoporous silica nanoparticles is very attractive for biological applications. The cellular protein sequestration study of mesoporous silica nanoparticles was examined for further information of the intracellular pathway of endocytosed mesoporous silica nanoparticle materials. The surface functionality of mesoporous silica nanoparticle materials demonstrated selectivity among the materials and cancer and normal cell lines. We aimed to determine

  3. Oil absorption in mesoporous silica particles

    Directory of Open Access Journals (Sweden)

    Radislav Filipović

    2010-12-01

    Full Text Available Mesoporous silica particles were prepared from highly basic sodium silicate solutions, having different silica modulus and SiO2 concentrations, by adding sulphuric acid at different temperatures. Pore structure of prepared silica particles (aggregates is strongly influenced by processing conditions and easy controllable in broad range of the specific surface area, pore size, pore volume and size distribution. It is shown that there is a clear correlation between volume of absorbed oil and processing parameters used in preparation of silica aggregates. Thus, oil absorption is higher in the samples prepared from sodium silicate solution with higher SiO2 concentration and at higher synthesis temperature.

  4. Objective evaluation of whiteness of cooked rice and rice cakes using a portable spectrophotometer.

    Science.gov (United States)

    Goto, Hajime; Asanome, Noriyuki; Suzuki, Keitaro; Sano, Tomoyoshi; Saito, Hiroshi; Abe, Yohei; Chuba, Masaru; Nishio, Takeshi

    2014-03-01

    The whiteness of cooked rice and rice cakes was evaluated using a portable spectrophotometer with a whiteness index (WI). Also, by using boiled rice for measurement of Mido values by Mido Meter, it was possible to infer the whiteness of cooked rice without rice cooking. In the analysis of varietal differences of cooked rice, 'Tsuyahime', 'Koshihikari' and 'Koshinokaori' showed high whiteness, while 'Satonoyuki' had inferior whiteness. The whiteness of rice cakes made from 'Koyukimochi' and 'Dewanomochi' was higher than the whiteness of those made from 'Himenomochi' and 'Koganemochi'. While there was a significant correlation (r = 0.84) between WI values and whiteness scores of cooked rice by the sensory test, no correlation was detected between the whiteness scores and Mido values, indicating that the values obtained by a spectrophotometer differ from those obtained by a Mido Meter. Thus, a spectrophotometer may be a novel device for measurement of rice eating quality.

  5. RiceAtlas, a spatial database of global rice calendars and production.

    Science.gov (United States)

    Laborte, Alice G; Gutierrez, Mary Anne; Balanza, Jane Girly; Saito, Kazuki; Zwart, Sander J; Boschetti, Mirco; Murty, M V R; Villano, Lorena; Aunario, Jorrel Khalil; Reinke, Russell; Koo, Jawoo; Hijmans, Robert J; Nelson, Andrew

    2017-05-30

    Knowing where, when, and how much rice is planted and harvested is crucial information for understanding the effects of policy, trade, and global and technological change on food security. We developed RiceAtlas, a spatial database on the seasonal distribution of the world's rice production. It consists of data on rice planting and harvesting dates by growing season and estimates of monthly production for all rice-producing countries. Sources used for planting and harvesting dates include global and regional databases, national publications, online reports, and expert knowledge. Monthly production data were estimated based on annual or seasonal production statistics, and planting and harvesting dates. RiceAtlas has 2,725 spatial units. Compared with available global crop calendars, RiceAtlas is nearly ten times more spatially detailed and has nearly seven times more spatial units, with at least two seasons of calendar data, making RiceAtlas the most comprehensive and detailed spatial database on rice calendar and production.

  6. The Glycemic Index of Rice and Rice Products: A Review, and Table of GI Values.

    Science.gov (United States)

    Kaur, Bhupinder; Ranawana, Viren; Henry, Jeyakumar

    2016-01-01

    Rice is the principle staple and energy source for nearly half the world's population and therefore has significant nutrition and health implications. Rice is generally considered a high glycemic index (GI) food, however, this depends on varietal, compositional, processing, and accompaniment factors. Being a major contributor to the glycemic load in rice eating populations, there is increasing concern that the rising prevalence of insulin resistance is as a result of the consumption of large amounts of rice. Devising ways and means of reducing the glycemic impact of rice is therefore imperative. This review gathers studies examining the GI of rice and rice products and provides a critical overview of the current state of the art. A table collating published GI values for rice and rice products is also included.

  7. Weedy (red) rice: an emerging constraint to global rice production

    NARCIS (Netherlands)

    Ziska, L.H.; Gealy, D.R.; Burgos, N.; Caicedo, A.L.; Gressel, J.; Lawton-Rauh, A.L.; Avila, L.A.; Theisen, Giovani; Norsworthy, J.; Ferrero, A.; Vidotto, F.; Johnson, D.E.; Ferreira, F.G.; Marchesan, E.; Menezes, V.; Cohn, M.A.; Linscombe, S.; Carmona, L.; Tang, R.; Merotto, A.

    2015-01-01

    Ongoing increases in the human population necessitate that rice will continue to be a critical aspect of food security for the twenty-first century. While production must increase in the coming decades to meet demand, such increases will be accompanied by diminished natural resources and rising

  8. Can herbicide safeners allow selective control of weedy rice infesting rice crops?

    Science.gov (United States)

    Busi, Roberto; Nguyen, Nghia K; Chauhan, Bhagirath S; Vidotto, Francesco; Tabacchi, Maurizio; Powles, Stephen B

    2017-01-01

    Rice is a major field crop of paramount importance for global food security. However, the increased adoption of more profitable and resource-efficient direct-seeded rice (DSR) systems has contributed to greater weed infestations, including weedy rice, which has become a severe problem in several Asian regions. In this study we have developed a conceptually novel method to protect rice plants at high doses of clomazone and triallate. The insecticide phorate applied to rice seeds provided a substantial level of protection against the herbicides clomazone or triallate. A quantity of 15 kg phorate ha(-1) significantly increased the LD50 values, which were more than twofold greater than for rice plants treated only with clomazone. A quantity of 20 kg phorate ha(-1) in combination with 2000 g triallate ha(-1) safened rice plants (80% survival) with LD50 >3.4-fold greater than in phorate-untreated rice. Weed control efficacy was not lowered by the presence of phorate-treated rice seeds. Weedy rice is one of the most damaging global weeds and a major threat to DSR systems. In this study we have developed a proof-of-concept method to allow selective weedy rice control in rice crops. We call for herbicide discovery programmes and research to identify candidate safener and herbicide combinations to achieve selective herbicide control of weedy rice and alleviate weed infestations in global rice crops. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  9. Silica cubes with tunable coating thickness and porosity : From hematite filled silica boxes to hollow silica bubbles

    NARCIS (Netherlands)

    Castillo, Sonja I R; Ouhajji, Samia; Fokker, Sander; Erné, Ben H.; Schneijdenberg, Chris T W M; Thies - Weesie, Dominique; Philipse, Albert P.; Thies - Weesie, Dominique

    2014-01-01

    We investigate the material properties of micron-sized silica coated cubic colloids, focusing on the coating thickness and porosity. The thickness of the silica coating of core-shell α-Fe2O3@SiO2 cubes and their corresponding hollow cubes can be tuned between 20 and 80 nm, spanning the range of

  10. Hunger, food and drink in Brazilian popular music: a brief overview.

    Science.gov (United States)

    de Vasconcelos, Francisco de Assis Guedes; Vasconcelos, Mariana Perrelli; de Vasconcelos, Iris Helena Guedes

    2015-01-01

    The article reflects on how the themes of hunger, consumption of soft drinks and consumption of beans and rice are addressed in Brazilian popular music. We investigate the years of military dictatorship (1964-1985). The focus of the analysis is on the so-called protest song, a musical genre characterized by aesthetic, cultural, political, ideological and social criticism to military rule. The study of the ideology and philosophy of language of Mikhail Bakhtin is the theoretical reference; especially his concepts of "ideological sign" and "word." Analysis reveals that the protest song portrayed elements of the economic, political and social contexts and led to the diffusion of healthy or unhealthy eating habits or ideologies, contributing to the construction of the Brazilian dietary identity.

  11. Rice brans, rice bran oils, and rice hulls: composition, food and industrial uses, and bioactivities in humans, animals, and cells.

    Science.gov (United States)

    Friedman, Mendel

    2013-11-13

    Rice plants produce bioactive rice brans and hulls that have been reported to have numerous health-promoting effects in cells, animals, and humans. The main objective of this review is to consolidate and integrate the widely scattered information on the composition and the antioxidative, anti-inflammatory, and immunostimulating effects of rice brans from different rice cultivars, rice bran oils derived from rice brans, rice hulls, liquid rice hull smoke derived from rice hulls, and some of their bioactive compounds. As part of this effort, this paper also presents brief summaries on the preparation of health-promoting foods including bread, corn flakes, frankfurters, ice cream, noodles, pasta, tortillas, and zero-trans-fat shortening as well as industrial products such bioethanol and biodiesel fuels. Also covered are antibiotic, antiallergic, anticarcinogenic, antidiabetic, cardiovascular, allelochemical, and other beneficial effects and the mechanisms of the bioactivities. The results show that food-compatible and safe formulations with desirable nutritional and biological properties can be used to develop new multifunctional foods as well as bioethanol and biodiesel fuel. The overlapping aspects are expected to contribute to a better understanding of the potential impact of the described health-promoting potential of the rice-derived brans, oils, and hulls in food and medicine. Such an understanding will enhance nutrition and health and benefit the agricultural and industrial economies.

  12. Agriculture Education. Soybeans and Rice.

    Science.gov (United States)

    Stuttgart Public Schools, AR.

    This curriculum guide is designed for group instruction of secondary students enrolled in one or two semester-long courses in agricultural education. The guide presents units of study in the following areas: (1) soybeans, (2) rice, and (3) orientation. Each of the 17 units of instruction follows a typical format: terminal objective, specific…

  13. Antiviral Sulfoquinovosyldiacylglycerols (SQDGs from the Brazilian Brown Seaweed Sargassum vulgare

    Directory of Open Access Journals (Sweden)

    Erwan Plouguerné

    2013-11-01

    Full Text Available Total lipids from the Brazilian brown seaweed Sargassum vulgare were extracted with chloroform/methanol 2:1 and 1:2 (v/v at room temperature. After performing Folch partition of the crude lipid extract, the lipids recovered from the Folch lower layer were fractionated on a silica gel column eluted with chloroform, acetone and methanol. The fraction eluted with methanol, presented a strong orcinol-positive band characteristic of the presence of sulfatides when examined by TLC. This fraction was then purified by two successive silica gel column chromatography giving rise to fractions F4I86 and F4II90 that exhibited strong activity against herpes simplex virus type 1 and 2. The chemical structures present in both fractions were elucidated by ESI-MS and 1H/13C NMR analysis HSQC fingerprints based on their tandem–MS behavior as Sulfoquinovosyldiacylglycerols  (SQDGs. The main SQDG present in both fractions and responsible for the anti-herpes activity observed was identified as 1,2-di-O-palmitoyl-3-O-(6-sulfo-α-d-quinovopyranosyl-glycerol.

  14. Silica gel matrix immobilized Chlorophyta hydrodictyon africanum ...

    African Journals Online (AJOL)

    Aghomotsegin

    2015-08-05

    Aug 5, 2015 ... Chlorophyta hydrodictyon africanum was immobilized on a silica gel matrix to improve its mechanical properties. The algae-silica gel adsorbent was used for batch sorption studies of a cationic dye, methylene blue (MB). Optimum adsorption was obtained with a dosage of 0.8 g bio sorbent. Results.

  15. Biomimetic silica encapsultation of living cells

    Science.gov (United States)

    Jaroch, David Benjamin

    Living cells perform complex chemical processes on size and time scales that artificial systems cannot match. Cells respond dynamically to their environment, acting as biological sensors, factories, and drug delivery devices. To facilitate the use of living systems in engineered constructs, we have developed several new approaches to create stable protective microenvironments by forming bioinspired cell-membrane-specific silica-based encapsulants. These include vapor phase deposition of silica gels, use of endogenous membrane proteins and polysaccharides as a site for silica nucleation and polycondensation in a saturated environment, and protein templated ordered silica shell formation. We demonstrate silica layer formation at the surface of pluripotent stem-like cells, bacterial biofilms, and primary murine and human pancreatic islets. Materials are characterized by AFM, SEM and EDS. Viability assays confirm cell survival, and metabolite flux measurements demonstrate normal function and no major diffusion limitations. Real time PCR mRNA analysis indicates encapsulated islets express normal levels of genetic markers for β-cells and insulin production. The silica glass encapsulant produces a secondary bone like calcium phosphate mineral layer upon exposure to media. Such bioactive materials can improve device integration with surrounding tissue upon implantation. Given the favorable insulin response, bioactivity, and long-term viability observed in silica-coated islets, we are currently testing the encapsulant's ability to prevent immune system recognition of foreign transplants for the treatment of diabetes. Such hybrid silica-cellular constructs have a wide range of industrial, environmental, and medical applications.

  16. Magnetic core-shell silica particles

    NARCIS (Netherlands)

    Claesson, E.M.

    2007-01-01

    This thesis deals with magnetic silica core-shell colloids and related functionalized silica structures. Synthesis routes have been developed and optimized. The physical properties of these colloids have been investigated, such as the magnetic dipole moment, dipolar structure formation and

  17. Synthesis of silica nanosphere from homogeneous and ...

    Indian Academy of Sciences (India)

    WINTEC

    Abstract. Silica nanosphere was synthesized using homogeneous and heterogeneous systems, respectively. In homogeneous system, silica spheres were synthesized without cetyltrimethylammonium bromide (CTABr), which gave bimodal particle size and lower yield (77%). To improve the yield, CTABr was added and ...

  18. Tuning the mechanical properties of silica microcapsules

    NARCIS (Netherlands)

    Zhang, L.; D'Acunzi, M.; Kappl, M.; Imhof, A.; van Blaaderen, A.; Butt, H. -J; Graf, R.; Vollmer, D.

    2010-01-01

    Heat treatment is a standard method to increase the hardness of silica in various applications. Here, we tested the effect of high temperature annealing on the mechanical properties of silica microcapsules by force spectroscopy under point loads applied to the particle shell. The Young's modulus of

  19. Silica gel matrix immobilized Chlorophyta hydrodictyon africanum ...

    African Journals Online (AJOL)

    Chlorophyta hydrodictyon africanum was immobilized on a silica gel matrix to improve its mechanical properties. The algae-silica gel adsorbent was used for batch sorption studies of a cationic dye, methylene blue (MB). Optimum adsorption was obtained with a dosage of 0.8 g bio sorbent. Results from sorption studies ...

  20. Chemical immobilisation of humic acid on silica

    NARCIS (Netherlands)

    Koopal, L.K.; Yang, Y.; Minnaard, A.J.; Theunissen, P.L.M.; Riemsdijk, W.H. van

    1998-01-01

    Immobilisation of purified Aldrich humic acid (PAHA) on aminopropyl silica and glutaraldehyde-activated aminopropyl silica has been investigated. In general the humic acid is bound to the solid by both physical and chemical bonds. The physically adsorbed HA can be released to a large extent at high

  1. Vitronectin protects alveolar macrophages from silica toxicity.

    Science.gov (United States)

    Wisniowski, P E; Spech, R W; Wu, M; Doyle, N A; Pasula, R; Martin, W J

    2000-08-01

    Silicosis is an interstitial lung disease caused by the inhalation of crystalline silicon dioxide. Current concepts suggest that a crucial step in the development of silicosis is silica-induced injury of alveolar macrophages (AM). The adhesive protein vitronectin is a natural constituent of the lung, in which its function is largely unexplored. This study investigated a possible role for vitronectin in protecting AM from silica exposure. In this study, the concentration of vitronectin was shown to be increased in the bronchoalveolar lavage fluid of silica-treated rats. Vitronectin affinity for silica was shown both in vitro and in vivo by immunostaining. Vitronectin reduced silica-induced injury to cultured AM as determined with the (51)Cr release assay. Vitronectin reduced silica-induced free radical production as determined with a cell-free thiobarbituric acid assay. Additionally, vitronectin reduced the silica-induced respiratory burst in AM as determined with chemiluminescence. This study suggests that vitronectin may protect AM during the initial exposure to silica.

  2. A comparative study of competitiveness between different genotypes of weedy rice (Oryza sativa) and cultivated rice.

    Science.gov (United States)

    Dai, Lei; Dai, Weimin; Song, Xiaoling; Lu, Baorong; Qiang, Sheng

    2014-01-01

    Competition from weedy rice can cause serious yield losses to cultivated rice. However, key traits that facilitate competitiveness are still not well understood. To explore the mechanisms behind the strong growth and competitive ability, replacement series experiments were established with six genotypes of weedy rice from different regions and one cultivated rice cultivar. (1) Weedy rice from southern China had the greatest impact on growth and yield of cultivated rice throughout the entire growing season. Weedy rice from the northeast was very competitive during the early vegetative stage while the competitive effects of eastern weedy rice were more detrimental at later crop-growth stages. (2) As the proportion of weedy rice increased, plant height, tillers, above-ground biomass, and yield of cultivated rice significantly declined; the crop always being at disadvantage regardless of proportion. (3) Weedy biotypes with greater diversity as estimated by their Shannon indexes were more detrimental to the growth and yield of cultivated rice. Geographic origin (latitude) of weedy rice biotype, its mixture proportion under competition with the crop and its genetic diversity are determinant factors of the outcome of competition and the associated decline in the rice crop yield. © 2013 Society of Chemical Industry. © 2013 Society of Chemical Industry.

  3. Rice production in relation to soil quality under different rice-based cropping systems

    Science.gov (United States)

    Tran Ba, Linh; Sleutel, Steven; Nguyen Van, Qui; Thi, Guong Vo; Le Van, Khoa; Cornelis, Wim

    2016-04-01

    Soil quality of shallow paddy soils may be improved by introducing upland crops and thus a more diverse crop cultivation pattern. Yet, the causal relationship between crop performance and enhanced soil traits in rice-upland crop rotations remains elusive. The objectives of this study were to (i) find correlations among soil properties under different rice-upland crop systems and link selected soil properties to rice growth and yield, (ii) present appropriate values of soil parameters for sustainable rice productivity in heavy clay soil, (iii) evaluate the effect of rotating rice with upland crops on rice yield and economic benefit in a long-term experiment. A rice-upland crop rotational field experiment in the Vietnamese Mekong delta was conducted for 10 years using a randomized complete block design with four treatments and four replications. Treatments were: (i) rice-rice-rice (control - conventional system as farmers' practice), (ii) rice-maize-rice, (iii) rice-mung bean-rice, and (iv) rice-mung bean-maize. Soil and plant sampling were performed after harvest of the rice crop at the end of the final winter-spring cropping season (i.e. year 10). Results show differences in rice growth and yield, and economic benefit as an effect of the crop rotation system. These differences were linked with changes in bulk density, soil porosity, soil aggregate stability index, soil penetration resistance, soil macro-porosity, soil organic carbon, acid hydrolysable soil C and soil nutrient elements, especially at soil depth of 20-30 cm. This is evidenced by the strong correlation (P < 0.01) between rice plant parameters, rice yield and soil properties such as bulk density, porosity, penetration resistance, soil organic carbon and Chydrolysable. It turned out that good rice root growth and rice yield corresponded to bulk density values lower than 1.3 Mg m-3, soil porosity higher than 50%, penetration resistance below 1.0 MPa, and soil organic carbon above 25 g kg-1. The optimal

  4. Amazon, priority for Brazilian National Defense Policy

    National Research Council Canada - National Science Library

    Pereira, Sergio

    2000-01-01

    .... The Brazilian national defense policy, issued in 1996, the first in the history of the country, established directives to orient the Brazilian military strategic planning as well as diplomatic...

  5. Does vitreous silica contradict the toxicity of the crystalline silica paradigm?

    Science.gov (United States)

    Ghiazza, Mara; Polimeni, Manuela; Fenoglio, Ivana; Gazzano, Elena; Ghigo, Dario; Fubini, Bice

    2010-03-15

    "Vitreous silica" is a particular form of amorphous silica, much neglected in experimental studies on silica toxicity. In spite of the incorrect term "quartz glass", often employed, this material is fully amorphous. When reduced in powdered form by grinding, the particulate appears most close to workplace quartz dust but, opposite to quartz, is not crystalline. As silicosis and lung cancer are also found among workers exposed to "quartz glass", the question arises of whether crystallinity is the prerequisite feature that makes a silica dust toxic. We compare here the behavior of comminuted quartz, vitreous silica, and monodispersed silica spheres, as it concerns surface reactivity and cellular responses involved in the accepted mechanisms of silica toxicity. Care was taken to choose samples of extreme purity, to avoid any effect due to trace contaminants. Quartz and vitreous silica, opposite to silica spheres, show irregular particles with sharp edges, stable surface radicals, and sustained release of HO(*) radicals via a Fenton-like mechanism. The evolution of the heat of adsorption of water as a function of coverage shows with quartz and vitreous silica a similar pattern of strong hydrophilic sites, nearly absent on the other silica specimen. When tested on a macrophage cell line (MH-S), vitreous silica and pure quartz, but not the monodispersed silica spheres, showed a remarkable potency in cytotoxicity, nitric oxide synthase activation and release of nitrite, and tumor necrosis factor-alpha production, suggesting a common behavior in inducing an oxidative stress. All of the above features appear to indicate that crystallinity might not be a necessary prerequisite to make a silica particle toxic.

  6. A silica nanoparticle based ionic material

    Science.gov (United States)

    Fernandes, Nikhil; Azad, Zubair; Giannelis, Emmanuel

    2011-03-01

    We report an ionic fluid consisting of silica nanoparticles as the anion, and amine-terminated polyethylene glycol as the cation. Unlike previous work that has required chemical functionalization of the silica surface, the charge on the nanoparticle anion is carried by the intrinsic surface hydroxyls, simplifying the synthesis, and thus making this a simple test system to probe the physics of these nanoscale ionic materials. Charge and steric factors result in excellent dispersion of the nanoparticles in the polymer matrix. The resulting material is a soft glass that has thermal and rheological properties that depend on the silica:polymer ratio. In particular, at a critical silica:polymer ratio, the ionic material shows a significant depression of the normalized heat of melting and the melting temperature compared to samples with higher or lower silica content (showing eutectic-like behaviour), and to controls without the ionic interaction between the polymer and the particle. Funded by KAUST-CU.

  7. Characteristics of Portland blast-furnace slag cement containing cement kiln dust and active silica

    Directory of Open Access Journals (Sweden)

    A. Abdel Rahman

    2016-09-01

    Full Text Available This investigation dealt with the effect of active silica, silica fume (SF or rice husk ash (RHA, on the mechanical and physico-chemical characteristics of the hardened blended cement pastes made of Portland blast-furnace slag cement (PSC containing cement kiln dust (CKD cured under normal conditions. Two blends made of PSC and CKD, improved by SF and two blends made of PSC and CKD improved by RHA were investigated. Hardened blended cement pastes were prepared from each cement blend by using water/cement ratio (W/C of 0.30 by weight and hydrated for various curing ages of 1, 3, 7, 28 and 90 days at the normal curing conditions under tap water at room temperature. Each cement paste was tested for its physico-chemical and mechanical characteristics; these characteristics include: compressive strength and kinetics of hydration. The phase composition of the formed hydration products was identified using X-ray diffraction (XRD and differential thermal analysis (DTA. It was found that the partial substitution of PSC by 10% and 15% of CKD is associated with an increase in the rate of hydration and a subsequent improvement of compressive strength of hardened PSC–CKD pastes. In addition, the replacement of PSC, in PSC–CKD blends, by 5% active silica was accompanied by further improvement of the physico-mechanical characteristics of the hardened PSC–CKD pastes.

  8. Fire effects on silica fractionation

    Science.gov (United States)

    Unzué-Belmonte, Dácil; Schaller, Jörg; Vandevenne, Floor; Barao, Lúcia; Struyf, Eric; Meire, Patrick

    2015-04-01

    Fire events are expected to increase due to climate change, both in number and intensity Effects range from changes in soil biogeochemistry up to the whole ecosystem functioning and morphology. While N, P and C cycling have received quite some attention, little attention was paid to fire effects on the biogeochemical Si cycle and the consequences after a fire event. The Si cycle is a globally important biogeochemical cycle, with strong connections to other biogeochemical cycles, including C. Dissolved silica is taken up by plants to form protective structures called phytoliths, which become a part of the soil and contribute strongly to soil Si cycling upon litter burial. Different silica fractions are found in soils, with phytoliths among the most easily soluble, especially compared to silicate minerals. A whole set of secondary non-biogenic fractions exist, that also have a high reactivity (adsorbed Si, reactive secondary minerals…). Biogenic and other pedogenic secondary Si stocks form an important filter between weathering of mineral silicates and eventual transport of dissolved Si to rivers and the coastal zone. We used a new method to analyze the different reactive fractions of silica in the litter layer of 3 ecosystems after different fire treatments. Using a continuous extraction of Si and Al in 0.5M NaOH at 85°C, biogenic and non-biogenic alkaline reactive Si fractions can be separated based on their Si/Al ratios and their reactivity. We analyzed the silica fractionation after two burning treatments (no heating, 350°C and 550°C) from three types of litter (spruce forest, beech forest and Sphagnum peat). Reactive Si from litter of spruce and beech forest was purely biogenic, based on the observed Si/Al ratio. Beech litter (~2.2 % BSi) had two different biogenic silica pools, one reactive and one more refractory. Spruce litter (~1.5% BSi) showed only one fraction of biogenic Si. There was negligible biogenic Si present in the peat samples (<0.1%). While

  9. Tier I Rice Model - Version 1.0 - Guidance for Estimating Pesticide Concentrations in Rice Paddies

    Science.gov (United States)

    Describes a Tier I Rice Model (Version 1.0) for estimating surface water exposure from the use of pesticides in rice paddies. The concentration calculated can be used for aquatic ecological risk and drinking water exposure assessments.

  10. The TIGR Rice Genome Annotation Resource: improvements and new features

    National Research Council Canada - National Science Library

    Ouyang, Shu; Zhu, Wei; Hamilton, John; Lin, Haining; Campbell, Matthew; Childs, Kevin; Thibaud-Nissen, Françoise; Malek, Renae L; Lee, Yuandan; Zheng, Li; Orvis, Joshua; Haas, Brian; Wortman, Jennifer; Buell, C Robin

    2007-01-01

    In The Institute for Genomic Research Rice Genome Annotation project (http://rice.tigr.org), we have continued to update the rice genome sequence with new data and improve the quality of the annotation...

  11. Environmentally-Friendly Dense and Porous Geopolymers Using Fly Ash and Rice Husk Ash as Raw Materials

    Directory of Open Access Journals (Sweden)

    Daniele Ziegler

    2016-06-01

    Full Text Available This paper assesses the feasibility of two industrial wastes, fly ash (FA and rice husk ash (RHA, as raw materials for the production of geopolymeric pastes. Three typologies of samples were thus produced: (i halloysite activated with potassium hydroxide and nanosilica, used as the reference sample (HL-S; (ii halloysite activated with rice husk ash dissolved into KOH solution (HL-R; (iii FA activated with the alkaline solution realized with the rice husk ash (FA-R. Dense and porous samples were produced and characterized in terms of mechanical properties and environmental impact. The flexural and compressive strength of HL-R reached about 9 and 43 MPa, respectively. On the contrary, the compressive strength of FA-R is significantly lower than the HL-R one, in spite of a comparable flexural strength being reached. However, when porous samples are concerned, FA-R shows comparable or even higher strength than HL-R. Thus, the current results show that RHA is a valuable alternative to silica nanopowder to prepare the activator solution, to be used either with calcined clay and fly ash feedstock materials. Finally, a preliminary evaluation of the global warming potential (GWP was performed for the three investigated formulations. With the mix containing FA and RHA-based silica solution, a reduction of about 90% of GWP was achieved with respect to the values obtained for the reference formulation.

  12. Synthesis of zeolite from rice husk ash waste of brick industries as hydrophobic adsorbent for fuel grade ethanol purification

    Science.gov (United States)

    Purnomo, A.; Alhanif, M.; Khotimah, C.; Zuhra, UA; Putri, BR; Kumoro, AC

    2017-11-01

    A lot of researchers have devoted on ethanol utilization as renewable energy to substitute petroleum based gasoline. When ethanol is being used as a new fuel candidate, it should have at least of 99.5% purity. Usually produced via sugar fermentation process, further purification of ethanol from other components in fermentation broth to obtain its fuel grade is a crucial step. The purpose of this research is to produce synthetic zeolite as hydrophobic adsorbent from rice husk ash for ethanol-water separation and to investigate the influence of weight, adsorption time and initial ethanol concentration on zeolite adsorption capacity. This research consisted of rice husk silica extraction, preparation of hydrophobic zeolite adsorbent, physical characterization using SEM, EDX and adsorption test for an ethanol-water solution. Zeolite with highest adsorption capacity was obtained with 15: 1 alumina silica composition. The best adsorption condition was achieved when 4-gram hydrophobic zeolite applied for adsorption of 100 mL of 10% (v/v) ethanol-water solution for 120 minutes, which resulted in ethanol with 98.93% (v/v) purity. The hydrophobic zeolite from rice husk ash is a potential candidate as an efficient adsorbent to purify raw ethanol into fuel grade ethanol. Implementation of this new adsorbent for ethanol production in commercial scale may reduce the energy consumption of that usually used for the distillation processes.

  13. Brazilian medical publications: citation patterns for Brazilian-edited and non-Brazilian literature

    Directory of Open Access Journals (Sweden)

    J.R. Cunha-Melo

    2006-08-01

    Full Text Available Today, the quality of a scientific article depends on the periodical in which it is published and on the number of times the article is cited in the literature. In Brazil, the criteria for the evaluation of this scientific production are improving. However, there is still some resistance, with authors arguing that Brazilian publications must be preferentially addressed to the national readers and, therefore, they should ideally be written in Portuguese. In order to determine the kind of scientific journals cited in the reference lists of articles published in medical periodicals edited in Brazil, in the present study we determine the rate of Portuguese/English citations. Three issues of 43 periodicals (19 indexed in SciELO, 10 in PubMed, 10 in LILACS, and 4 in the ISI-Thompson base of different medical specialties were analyzed, and the number of both Portuguese and English citations in the reference list of each article was recorded. The results showed that in Brazilian-edited journals the mean number of citations/article was 20.9 ± 6.9 and the percentage of citations of international non-Brazilian periodicals was 86.0 ± 11.2%. Of the latter, 94.4 ± 7.0 are indexed by ISI-Thompson. Therefore, we conclude that Brazilian medical scientists cite the international non-Brazilian periodicals more than the national journals, and most of the cited papers are indexed by ISI-Thompson.

  14. The role of momilactones in rice allelopathy.

    Science.gov (United States)

    Kato-Noguchi, Hisashi; Peters, Reuben J

    2013-02-01

    Large field screening programs and laboratory experiments in many countries have indicated that rice is allelopathic and releases allelochemical(s) into its environment. A number of compounds, such as phenolic acids, fatty acids, phenylalkanoic acids, hydroxamic acids, terpenes, and indoles, have been identified as potential rice allelochemicals. However, the studies reviewed here demonstrate that the labdane-related diterpenoid momilactones are the most important, with momilactone B playing a particularly critical role. Rice plants secrete momilactone B from their roots into the neighboring environments over their entire life cycle at phytotoxic levels, and momilactone B seems to account for the majority of the observed rice allelopathy. In addition, genetic studies have shown that selective removal of the momilactones only from the complex mixture found in rice root exudates significantly reduces allelopathy, demonstrating that these serve as allelochemicals, the importance of which is reflected in the presence of a dedicated momilactone biosynthetic gene cluster in the rice genome.

  15. Novel transgenic rice-based vaccines.

    Science.gov (United States)

    Azegami, Tatsuhiko; Itoh, Hiroshi; Kiyono, Hiroshi; Yuki, Yoshikazu

    2015-04-01

    Oral vaccination can induce both systemic and mucosal antigen-specific immune responses. To control rampant mucosal infectious diseases, the development of new effective oral vaccines is needed. Plant-based vaccines are new candidates for oral vaccines, and have some advantages over the traditional vaccines in cost, safety, and scalability. Rice seeds are attractive for vaccine production because of their stability and resistance to digestion in the stomach. The efficacy of some rice-based vaccines for infectious, autoimmune, and other diseases has been already demonstrated in animal models. We reported the efficacy in mice, safety, and stability of a rice-based cholera toxin B subunit vaccine called MucoRice-CTB. To advance MucoRice-CTB for use in humans, we also examined its efficacy and safety in primates. The potential of transgenic rice production as a new mucosal vaccine delivery system is reviewed from the perspective of future development of effective oral vaccines.

  16. DETERMINATION OF SPATIAL INTEGRATION AND SUBSTITUTION OF FOREIGN RICE FOR LOCAL RICE IN GHANA

    Directory of Open Access Journals (Sweden)

    Philip Kofi ADOM

    2014-11-01

    Full Text Available This study tested for spatial integration in the rice market and the substitution of imported rice for local rice in Ghana. It is established that the markets for domestic imported rice are well-integrated, but not complete. The imperfect spatial integration of domestic foreign rice markets implies that the market provides opportunities for arbitrage. Price leadership roles are found to be determined by the kind of sub-inter-regional-trade network defined. However, in all, the Accra market emerged as a dominant market leader in the domestic foreign rice market. There is evidence of significant regional substitution of foreign rice for local rice in the long run, but the result is mixed in the short run. The result that local rice is not a perfect substitute for imported rice implies that price disincentive measures such as increasing the import tariffs on foreign rice will only produce a mild effect on increasing the producer price faced by local rice farmers, but aggravate the burden on households’ budget.

  17. Relative competitive ability of rice with strawhull and blackhull red rice biotypes

    Science.gov (United States)

    Weed interference depends largely upon the species composition of the weed community and an ability to compete with the cultured crop. Weedy red rice is a major weed pest of rice in the southern U.S. The focus of this study was to evaluate the competitive ability of rice against common, genetically ...

  18. Characterizing irrigation water requirements for rice production from the Arkansas Rice Research Verification Program

    Science.gov (United States)

    This study investigated rice irrigation water use in the University of Arkansas Rice Research Verification Program between the years of 2003 and 2011. Irrigation water use averaged 747 mm (29.4 inches) over the nine years. A significant 40% water savings was reported for rice grown under a zero gr...

  19. Reaction of rice cultivars to a virulent Rice Yellow Mottle Virus strain ...

    African Journals Online (AJOL)

    has long been an important food staple for many traditional rice growing communities. Key developments in efforts to improve rice ... Appropriate sources of resistance to RYMV should be identified and characterised in order to pyramid genes for both complete and partial resistance. In this study, reaction of nine (9) rice ...

  20. RiceAtlas, a spatial database of global rice calendars and production

    NARCIS (Netherlands)

    Laborte, Alice G.; Gutierrez, Mary Anne; Balanza, Jane Girly; Saito, Kazuki; Zwart, Sander J.; Boschetti, Mirco; Murty, M. V.R.; Villano, Lorena; Aunario, Jorrel Khalil; Reinke, Russell; Koo, Jawoo; Hijmans, Robert J.; Nelson, Andrew

    2017-01-01

    Knowing where, when, and how much rice is planted and harvested is crucial information for understanding the effects of policy, trade, and global and technological change on food security. We developed RiceAtlas, a spatial database on the seasonal distribution of the world's rice production. It

  1. Effect of volunteer rice infestation on grain quality and yield of rice

    Science.gov (United States)

    Volunteer rice (Oryza sativa L.) plants arise from shattered seeds of the previous crop, which could reduce the yield of cultivated rice and the commercial value of harvested grain. Volunteer rice plants from a cultivar other than the current crop produce grains that may differ in physico-chemical t...

  2. Mycotoxin Contamination of Rice in China.

    Science.gov (United States)

    Sun, Xiang Dong; Su, Ping; Shan, Hong

    2017-03-01

    Mycotoxin contamination in rice is generally lower than in other cereals such as corn or wheat. However, over 65% of the population in China consumes rice as a staple food. Due to the diversity of the climate across China, the southern region is characterized by high temperatures and humidities, especially in rainy season. Such conditions are optimal for the growth of fungi. The accumulative and transferrable characteristics of fungi mycotoxins pose a great potential threat as confirmed by high incidences of liver cancer in the Yangtze delta region. Major mycotoxins identified in China are aflatoxins and ochratoxin A, as well as fumonisins. The contents of aflatoxin B1 (AFB1 ) in rice are varied among different provinces and regions and generally less than 5 μg/kg. Although high incidences of positive aflatoxins samples have widely been detected, few samples were detected as exceeding the national's maximum residue limit (10 μg/kg). Limited information is available on risk assessment of human health hazards of mycotoxins in rice, children should be paid more attention to due to their having the highest mycotoxins exposure level, although the risks are generally at low levels from rice. Mycotoxins are mainly distributed in the outer layer of the paddy rice (also called rough rice, referring to whole rice grain with the hulls), and the AFB1 content in bran is 8.4 times greater than that in brown rice (hulled rice). Further investigation should focus on isolation and identification of mycotoxins-producing fungal strains, especially unknown mycotoxigenic fungal strains determination. Infection resistant rice breeding of mycotoxigenic fungal species may be a fundamental approach to guaranteeing rice safety in China. © 2017 Institute of Food Technologists®.

  3. Guyana Rice Supply Chain Risk Assessment

    OpenAIRE

    World Bank

    2011-01-01

    This report is the outcome of assessment and is intended as an advisory note to the Ministry of Agriculture (MoA) and Guyana Rice Development Board (GRDB) to enable them to identify a strategy and potential public investments to improve current risk-management practices in the rice supply chain. This report identifies the major risks facing the rice supply chain, ranks them in terms of the...

  4. Cropping system diversification for food production in Mindanao rubber plantations: a rice cultivar mixture and rice intercropped with mungbean

    National Research Council Canada - National Science Library

    Rosa Fe Hondrade; Edwin Hondrade; Lianqing Zheng; Francisco Elazegui; Jo-Anne Lynne Joy E Duque; Christopher C Mundt; Casiana M Vera Cruz; Karen A Garrett

    2017-01-01

    .... We evaluated the potential for planting rice, mungbean, rice cultivar mixtures, and rice intercropped with mungbean in young rubber plantations in experiments in the Arakan Valley of Mindanao in the Philippines...

  5. Metal-silica sol-gel materials

    Science.gov (United States)

    Stiegman, Albert E. (Inventor)

    2002-01-01

    The present invention relates to a single phase metal-silica sol-gel glass formed by the co-condensation of a transition metal with silicon atoms where the metal atoms are uniformly distributed within the sol-gel glass as individual metal centers. Any transition metal may be used in the sol-gel glasses. The present invention also relates to sensor materials where the sensor material is formed using the single phase metal-silica sol-gel glasses. The sensor materials may be in the form of a thin film or may be attached to an optical fiber. The present invention also relates to a method of sensing chemicals using the chemical sensors by monitoring the chromatic change of the metal-silica sol-gel glass when the chemical binds to the sensor. The present invention also relates to oxidation catalysts where a metal-silica sol-gel glass catalyzes the reaction. The present invention also relates to a method of performing oxidation reactions using the metal-silica sol-gel glasses. The present invention also relates to organopolymer metal-silica sol-gel composites where the pores of the metal-silica sol-gel glasses are filled with an organic polymer polymerized by the sol-gel glass.

  6. Preparation and Characterization of Silica Aerogel Microspheres.

    Science.gov (United States)

    Chen, Qifeng; Wang, Hui; Sun, Luyi

    2017-04-20

    Silica aerogel microspheres based on alkali silica sol were synthesized using the emulsion method. The experimental results revealed that the silica aerogel microspheres (4-20 µm in diameter) were mesoporous solids with an average pore diameter ranging from 6 to 35 nm. The tapping densities and specific surface areas of the aerogel microspheres are in the range of 0.112-0.287 g/cm³ and 207.5-660.6 m²/g, respectively. The diameter of the silica aerogel microspheres could be tailored by varying the processing conditions including agitation rate, water/oil ratio, mass ratio of Span 80: Tween 80, and emulsifier concentration. The effects of these parameters on the morphology and textural properties of the synthesized silica aerogel microspheres were systematically investigated. Such silica aerogel microspheres can be used to prepare large-scale silica aerogels at an ambient pressure for applications in separation and high efficiency catalysis, which requires features of high porosity and easy fill and recovery.

  7. Study of rice. gamma. -irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lien, J.J.; Chau, R.S.; Chen, S.C.; Chu, S.L.; Fu, Y.K.; Fang, C.K.; Fu, Y.H.

    1981-03-01

    The purpose of this experiment was to investigate whether the /sup 60/Co gamma-irradiated milled rice packed in economic and practical sealed bags could be preserved in common granaries in Taiwan for more than one year rather than slightly over one month without quality deterioration. As a result of this experiment we found that during the preservation of over a period of 18 months, the contents, such as moisture, ash, protein and fiber, of Tainan-5 Bon-Lai (Japonica Type) rice irradiated with 20 and 40 krad doses were quite stable, whereas reducing sugar showed slight fluctuations but did not vary significantly either. The fat, vitamin B/sub 1/ and niacin contents were found being reduced, while the increase in fatty acid content was an inevitable phenomenon along with the proceeding of the preservation.

  8. Bioethanol production from rice straw residues

    Directory of Open Access Journals (Sweden)

    Elsayed B. Belal

    2013-01-01

    Full Text Available A rice straw -cellulose utilizing mold was isolated from rotted rice straw residues. The efficient rice straw degrading microorganism was identified as Trichoderma reesei. The results showed that different carbon sources in liquid culture such as rice straw, carboxymethyl cellulose, filter paper, sugar cane bagasse, cotton stalk and banana stalk induced T. reesei cellulase production whereas glucose or Potato Dextrose repressed the synthesis of cellulase. T. reesei cellulase was produced by the solid state culture on rice straw medium. The optimal pH and temperature for T. reesei cellulase production were 6 and 25 ºC, respectively. Rice straw exhibited different susceptibilities towards cellulase to their conversion to reducing sugars. The present study showed also that, the general trend of rice straw bioconversion with cellulase was more than the general trend by T. reesei. This enzyme effectively led to enzymatic conversion of acid, alkali and ultrasonic pretreated cellulose from rice straw into glucose, followed by fermentation into ethanol. The combined method of acid pretreatment with ultrasound and subsequent enzyme treatment resulted the highest conversion of lignocellulose in rice straw to sugar and consequently, highest ethanol concentration after 7 days fermentation with S. cerevisae yeast. The ethanol yield in this study was about 10 and 11 g.L-1.

  9. Wheat products as acceptable substitutes for rice.

    Science.gov (United States)

    Yu, B H; Kies, C

    1993-07-01

    The objective of the study was to compare the acceptability to semi-trained US American and Asian palatability panelist, of four wheat products processed to be possible replacers of rice in human diets. Products evaluated using rice as the control standard of excellence were steamed whole wheat, couscous (steamed, extracted wheat flour semolina), rosamarina (rice shaped, extracted wheat flour pasta), and bulgar (steamed, pre-cooked partly debranned, cracked wheat). Using a ten point hedonic rating scale, both groups of panelists gave rosamarina closely followed by couscous, most favorable ratings although these ratings were somewhat lower than that of the positive control, steamed polished rice. Bulgar wheat was given the lowest evaluation and was, in general, found to be an unacceptable replacement for rice by both American and Asian judges because of its dark, 'greasy' color and distinctive flavor. In their personal dietaries, judges included rice from 0.25 to 18 times per week with the Asian judges consuming rice significantly more times per week than did the American judges (10.8 +/- 4.71 vs 1.75 +/- 1.65, p < 0.01). However, rice consumption patterns, nationality, race, or sex of the judges was not demonstrated to affect scoring of the wheat products as rice replacers.

  10. Controlled silica synthesis inspired by diatom silicon biomineralization

    NARCIS (Netherlands)

    Vrieling, EG; Sun, QY; Beelen, TPM; Hazelaar, S; Gieskes, WWC; van Santen, RA; Sommerdijk, NAJM

    Silica becomes increasingly used in chemical, pharmaceutical, and (nano)technological processes', resulting in an increased demand for well-defined silicas and silica-based materials. The production of highly structured silica from cheap starting materials and under ambient conditions, which is a

  11. Rice Multi-Gene Analysis

    Indian Academy of Sciences (India)

    gdyang

    Maps of all the intronic MIR genes analyzed using MPSS database in rice. Click here for a legend that explains the icons and colors in the image below. Click here to jump in the page below to the specific gene. osa-MIR159f osa-MIR399i osa-MIR418 osa-MIR437 osa-MIR439b osa-MIR439j osa-MIR440 osa-MIR442.

  12. The formation of helical mesoporous silica nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Wan Xiaobing; Pei Xianfeng; Zhao Huanyu; Chen Yuanli; Guo Yongmin; Li Baozong; Yang Yonggang [Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry and Chemical Engineering, Suzhou (Soochow) University, Suzhou 215123 (China); Hanabusa, Kenji [Department of Functional Polymer Science, Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567 (Japan)], E-mail: ygyang@suda.edu.cn

    2008-08-06

    Three chiral cationic gelators were synthesized. They can form translucent hydrogels in pure water. These hydrogels become highly viscous liquids under strong stirring. Mesoporous silica nanotubes with coiled pore channels in the walls were prepared using the self-assemblies of these gelators as templates. The mechanism of the formation of this hierarchical nanostructure was studied using transmission electron microscopy at different reaction times. The results indicated that there are some interactions between the silica source and the gelator. The morphologies of the self-assemblies of gelators changed gradually during the sol-gel transcription process. It seems that the silica source directed the organic self-assemblies into helical nanostructures.

  13. Proteomics of Rice Seed Germination

    Directory of Open Access Journals (Sweden)

    Dongli eHe

    2013-07-01

    Full Text Available Seed is a condensed form of plant. Under suitable environmental conditions, it can resume the metabolic activity from physiological quiescent status, and mobilize the reserves, biosynthesize new proteins, regenerate organelles and cell membrane, eventually protrude the radicle and enter into seedling establishment. So far, how these activities are regulated in a coordinated and sequential manner is largely unknown. With the availability of more and more genome sequence information and the development of mass spectrometry (MS technology, proteomics has been widely applied in analyzing the mechanisms of different biological processes, and proved to be very powerful. Regulation of rice seed germination is critical for rice cultivation. In recent years, a lot of proteomic studies have been conducted in exploring the gene expression regulation, reserves mobilization and metabolisms reactivation, which brings us new insights on the mechanisms of metabolism regulation during this process. Nevertheless, it also invokes a lot of questions. In this mini-review, we summarized the progress in the proteomic studies of rice seed germination. The current challenges and future perspectives were also discussed, which might be helpful for the following studies.

  14. Variability in contents of thiamine and riboflavin in brown rice, crude oil in brown rice and bran-polish, and silicon in hull of IR rices.

    Science.gov (United States)

    Villareal, C P; Juliano, B O

    1989-09-01

    Among 30 IR varieties, variety had greater effect on thiamine content of brown rice than season. Both season and variety affected riboflavin content. Purple- and red-pericarped Philippines rices had higher riboflavin and crude protein contents than IR rices. Crude oil contents of brown rice and bran-polish of 19 IR rices were significantly affected by variety, but only brown rice oil content was significantly affected by season. Bran-polish of waxy rice IR29 had the highest oil content. Silicon content of hull of 16 IR rices showed significant variation due to variety and season and tended to be higher in the dry season crop. Variety rankings in nutrient composition were not consistent for the two crops. The levels of nutrients of IR rices were within the range of values reported for other rices.

  15. Ultrastructure of the wild rice Oryza grandiglumis (Gramineae in Costa Rica

    Directory of Open Access Journals (Sweden)

    Ethel Sánchez

    2006-06-01

    Full Text Available Oryza grandiglumis is a wild species of rice endemic to tropical America. This species was first found in 1998 in the wetlands of Caño Negro, located in the northern part of Costa Rica. Twenty five plants of O. grandiglumis were processed for scanning electron microscope. An ultrastructural description of the leaf blade, ligule, auricles, spikelet and caryopsis, with an emphasis on structures of taxonomic value. The leaf blade has a characteristic cuticular wax pattern, composed of dense rod-like structures, and is surrounded by papillae, zipper- like silica cells, abundant bulky prickle trichomes, and hooked trichomes. The blade’s edge has three rows of hooked prickle trichomes of various sizes. The auricles wrapped the culm, with long attenuated trichomes at the edges; the base was surrounded by oblong cells. The ligule is a blunt membrane covered by short prickle trichomes. Spikelet morphology is characteristic of the Poaceae family, but the sterile lemmas were nearly as long as the fertile lemmas, and they have an unique crown-like structure of lignified spines between the rachilla and the fertile lemmas. Comparison with Brazilian specimens of O. grandiglumis revealed little differences in the ultrastructural characteristics. Rev. Biol. Trop. 54(2: 377-385. Epub 2006 Jun 01.El arroz silvestre Oryza grandiglumis es endémico de América. Se localiza en la zona norte de Costa Rica, principalmente en el humedal de Caño Negro y del Río Medio Queso. Es una planta vigorosa y grande. Su nombre deriva del gran tamaño de las lemas estériles (glumas. Presentamos una descripción ultraestructural de la lámina foliar, lígula, aurículas, espiguilla y cariópside, con énfasis en las estructuras de valor taxonómico, usando el microscopio electrónico de barrido. La lámina foliar se caracteriza por presentar un patrón de cera cuticular en forma de densos bastoncillos. Presenta estomas rodeados de papilas, células de sílice en forma crenada

  16. Comparison of frailty among Japanese, Brazilian Japanese descendants and Brazilian community-dwelling older women.

    Science.gov (United States)

    Sampaio, Priscila Yukari Sewo; Sampaio, Ricardo Aurélio Carvalho; Yamada, Minoru; Ogita, Mihoko; Arai, Hidenori

    2015-06-01

    To investigate frailty in Japanese, Brazilian Japanese descendants and Brazilian older women. The collected data included sociodemographic and health-related characteristics, and the frailty index Kihon Checklist. We analyzed the differences between the mean scores of Kihon Checklist domains (using ancova) and the percentage of frail women (using χ(2)-test). We carried out a binary logistic regression with Kihon Checklist domains. A total of 211 participants (Japanese n = 84, Brazilian Japanese descendants n = 55, Brazilian n = 72) participated in this research. The Brazilian participants had the highest total Kihon Checklist scores (more frail), whereas the Brazilian Japanese descendants had the lowest scores (P Brazilian group had more participants with oral dysfunction (P Brazilian women were likely to be more frail than the participants in other groups. More than the environment itself, the lifestyle and sociodemographic conditions could affect the frailty of older Brazilian women. © 2014 Japan Geriatrics Society.

  17. Porous Silica Particles As Chromatographic Separation Media: A Review

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Won Jo [Inha University, Incheon (Korea, Republic of)

    2014-09-15

    Porous silica particles are the most prevailing raw material for stationary phases of liquid chromatography. During a long period of time, various methodologies for production of porous silica particles have been proposed, such as crashing and sieving of xerogel, traditional dry or wet process preparation of conventional spherical particles, preparation of hierarchical mesoporous particles by template-mediated pore formation, repeated formation of a thin layer of porous silica upon nonporous silica core (core-shell particles), and formation of specific silica monolith followed by grinding and calcination. Recent developments and applications of useful porous silica particles will be covered in this review. Discussion on sub-3 µm silica particles including nonporous silica particles, carbon or metal oxide clad silica particles, and molecularly imprinted silica particles, will also be included. Next, the individual preparation methods and their feasibilities will be collectively and critically compared and evaluated, being followed by conclusive remarks and future perspectives.

  18. Amorphous silica biomineralizations in Schoenoplectus californicus (Cyperaceae): their relation with maturation stage and silica availability

    OpenAIRE

    Fernández Honaine, Mariana; Borrelli, Natalia Lorena; Osterrieth, Margarita Luisa; del Río, Laura Sombra

    2015-01-01

    The factors involved on the silicification process in Cyperaceae are scarcely known. In this study we analyse the effect of maturation stage and silica availability on the production of amorphous silica biomineralizations in culms of Schoenoplectus californicus. Young and senescent culms were collected from ponds with different silica availability. Two complementary methodologies (calcination and staining techniques), light and scanning electron microscopy and EDS were applied for amorpho...

  19. INNOVATION IN BRAZILIAN SMALL COMPANIES

    National Research Council Canada - National Science Library

    Rodrigues, Tonny Kerley de Alencar; Lira, Átila De Melo; Naas, Irenilza De Alencar

    2015-01-01

    .... And the data confirms that small Brazilian companies generally have difficulties to sell their innovations. Keywords: innovation, small enterprises, patents. 1. INTRODUCTION Companies worldwide are looking to technological innovation as feasible for your market expansion (BURNS; STALKER, 1961; NELSON, 1993) alternative. In Brazil, the change an...

  20. BRAZILIAN EXPORTS OF MANUFACTURED WOOD

    Directory of Open Access Journals (Sweden)

    Rafael de Azevedo Calderon

    2010-08-01

    Full Text Available The present work deals with the Brazilian exports of sawnwood of non-coniferous, veneer sheets and plywood, from 1961 to 2002. The data regarding the three studied products, sawnwood of non-coniferous, veneer sheets and plywood, were joined through the method of Fisher so that an econometric evaluation of the market of the three products could be carried out. Supply and demand models of the Brazilian exports were specified. The results were satisfactory and they match with the literature. The supply of exports presented a positive answer in relation to the exporter's remuneration, to the production, to the use of the installed capacity (cycles of domestic economical activity and to the tendency, and negative in relation to the internal demand. The demand for the Brazilian exports was influenced positively by the world income, participation index and tendency, and negatively for the relative price. The low elasticity-price of the found demand can have implications in the conservation of the Brazilian forest resources because the exporters can increase the prices, reduce the amounts and still increase the incomes.

  1. Deforestation in the Brazilian Amazon

    NARCIS (Netherlands)

    Boekhout van Solinge, T.|info:eu-repo/dai/nl/156696207

    2015-01-01

    This essay takes a (green) criminological and multidisciplinary perspective on deforestation in the Brazilian Amazon, by focusing on the crimes and damages that are associated with Amazonian deforestation. The analysis and results are partly based on longer ethnographic stays in North Brazil (Amazon

  2. Interfacial interaction between the epoxidized natural rubber and silica in natural rubber/silica composites

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tiwen [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Jia, Zhixin, E-mail: zxjia@scut.edu.cn [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Luo, Yuanfang; Jia, Demin [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Peng, Zheng [Agricultural Product Processing Research Institute, Chinese Academy of Tropical Agriculture Sciences, Zhanjiang 524001 (China)

    2015-02-15

    Highlights: • Substantiate the ring open reaction between Si-OH of silica and epoxy groups of ENR. • ENR can act as a bridge between NR and silica to enhance the interfacial interaction. • As a modifier, ENR gets the potential to be used in the tread of green tire for improving the wet skid resistance apparently. - Abstract: The epoxidized natural rubber (ENR) as an interfacial modifier was used to improve the mechanical and dynamical mechanical properties of NR/silica composites. In order to reveal the interaction mechanism between ENR and silica, the ENR/Silica model compound was prepared by using an open mill and the interfacial interaction of ENR with silica was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and stress–strain testing. The results indicated that the ring-opening reaction occurs between the epoxy groups of ENR chains and Si-OH groups on the silica surfaces and the covalent bonds are formed between two phases, which can improve the dispersion of silica in the rubber matrix and enhance the interfacial combination between rubber and silica. The ring-opening reaction occurs not only in vulcanization process but also in mixing process, meanwhile, the latter seems to be more important due to the simultaneous effects of mechanical force and temperature.

  3. Benthic macroinvertebrates in Italian rice fields

    Directory of Open Access Journals (Sweden)

    Daniela Lupi

    2013-02-01

    Full Text Available Rice fields can be considered man-managed temporary wetlands. Five rice fields handled with different management strategies, their adjacent channels, and a spring were analysed by their benthic macroinvertebrate community to i evaluate the role of rice agroe- cosystem in biodiversity conservation; ii find indicator species which can be used to compare the ecological status of natural wetlands with rice agroecosystems; and iii find the influence of environmental variables on biodiversity. Different methods of data analysis with increasing degree of complexity – from diversity index up to sophisticated multivariate analysis – were used. The investigation provided a picture of benthic macroinvertebrates inhabiting rice agroecosystems where 173 taxa were identified, 89 of which detected in rice paddies. Among them, 4 phyla (Mollusca, Annelida, Nematomorpha, and Arthropoda, 8 classes (Bivalvia, Gastropoda, Oligochaeta, Hirudinea, Gordioida, Insecta, Branchiopoda, and Malacostraca, 24 orders, 68 families, 127 genera and 159 species have been found. Ten threatened and 3 invasive species were detected in the habitats examined. The information obtained by the different methods of data analysis allowed a more comprehensive view on the value of the components of rice agroecosystems. Data analyses highlighted significant differences between habitats (feeding channel and rice field, with higher diversity observed in channels, and emphasised the role of the water chemical-physical parameters. The period of water permanence in rice fields resulted to be only one of the factors influencing the community of benthic macroinvertebrates. The presence of rare/endangered species allowed characterising some stations, but it was less informative about management strategies in rice paddies because most of these species were absent in rice fields.

  4. Feasibility study on estimation of rice weevil quantity in rice stock using near-infrared spectroscopy technique

    Directory of Open Access Journals (Sweden)

    Puttinun Jarruwat

    2014-07-01

    Full Text Available Thai rice is favored by large numbers of consumers of all continents because of its excellent taste, fragrant aroma and fine texture. Among all Thai rice varieties, Thai Hommali rice is the most preferred. Classification of rice as premium quality requires that almost all grain kernels of the rice be perfectly whole with only a small quantity of foreign particles. Of all the foreign particles found in rice, rice weevils can wreck severest havoc on the quality and quantity of rice such that premium grade rice is transformed into low grade rice. It is widely known that rice millers adopt the "overdose" fumigation practice to control the birth and propagation of rice weevils, the practice of which inevitably gives rise to pesticide residues on rice which end up in the body of consumers. However, if population concentration of rice weevils could be approximated, right amounts of chemicals for fumigation would be applied and thereby no overdose is required. The objective of this study is thus to estimate the quantity of rice weevils in both milled rice and brown rice of Thai Hommali rice variety using the near infrared spectroscopy (NIRS technique. Fourier transforms near infrared (FT-NIR spectrometer was used in this research and the near-infrared wavelength range was 780–2500 nm. A total of 20 levels of rice weevil infestation with an increment of 10 from 10 to 200 mature rice weevils were applied to 1680 rice samples. The spectral data and quantity of weevils are analyzed by partial least square regression (PLSR to establish the model for prediction. The results show that the model is able to estimate the quantity of weevils in milled Hommali rice and brown Hommali rice with high $R_{\\rm val}^{2}$ of 0.96 and 0.90, high RPD of 6.07 and 3.26 and small bias of 2.93 and 2.94, respectively.

  5. Rice Blast Resistance of Transgenic Rice Plants with Pi-d2 Gene

    Directory of Open Access Journals (Sweden)

    De-xi CHEN

    2010-09-01

    Full Text Available Resistance to rice blast of transgenic rice lines harboring rice blast resistance gene Pi-d2 transformed from three different expression vectors of pCB6.3kb, pCB5.3kb and pZH01-2.72kb were analyzed. Nine advanced-generation transgenic rice lines with Pi-d2 gene displayed various resistance to 39 rice blast strains, and the highest disease-resistant frequency reached 91.7%. Four early-generation homozygous transgenic lines with Pi-d2 gene exhibited resistance to more than 81.5% of 58 rice blast strains, showing the characteristic of wide-spectrum resistance. The transgenic embryonic calli selected by the crude toxin of rice blast fungus showed that the callus induction rate of immature embryo from transgenic rice plants decreased as the concentration of crude toxin in the culture medium increased. When the concentration of crude toxin reached 40%, the callus induction rate of immature embryo from transgenic lines was 49.3%, and that of the receptor control was 5%. The disease incidence of neck blast of the transgenic rice lines in fields under induction was 0% to 50%, indicating that the rice blast resistance of transgenic rice lines is much higher than that of the receptor control.

  6. Anomalous enthalpy relaxation in vitreous silica

    DEFF Research Database (Denmark)

    Yue, Yuanzheng

    2015-01-01

    It is a challenge to calorimetrically determine the glass transition temperature (Tg) of vitreous silica. Here, we demonstrate that this challenge mainly arises from the extremely high sensitivity of the Tg to the hydroxyl content, but also from decrease of the Tg with repeating the calorimetric...... scans. It is known that the liquid fragility (i.e., the speed of the viscous slow-down of a supercooled liquid at its Tg during cooling) has impact on enthalpy relaxation in glass. Here, we find that vitreous silica (as a strong system) exhibits striking anomalies in both glass transition and enthalpy...... relaxation compared to fragile oxide systems. The anomalous enthalpy relaxation of vitreous silica is discovered by performing the hyperquenching-annealing-calorimetry experiments. We argue that the strong systems like vitreous silica and vitreous Germania relax in a structurally cooperative manner, whereas...

  7. Microscopic polyangiitis secondary to silica exposure.

    Science.gov (United States)

    Vega Miranda, Juliana; Pinto Peñaranda, Luis Fernando; Márquez Hernández, Javier Darío; Velásquez Franco, Carlos Jaime

    2014-01-01

    There is sufficient evidence of the capacity of silica to induce autoimmunity in patients with some type of genetic susceptibility. There are several autoimmune diseases related to this exposure (rheumatoid arthritis, Sjögren's syndrome, sarcoidosis, systemic sclerosis). Nodular silicosis (clinical expression of this exposure in lungs) generates apoptosis, inflammation, loss of tolerance and a respiratory burst. There is evidence that relates silica with induction of antineutrophil cytoplasmic antibodies, but, until it is better explained, the reports of systemic vasculitis secondary to silica exposure are inconclusive. We describe a case of a patient with a history of occupational exposure to silica who developed microscopic polyangiitis. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  8. Application of agrometeorological spectral model in rice area in southern Brazil

    Science.gov (United States)

    Leivas, Janice F.; de C. Teixeira, Antonio Heriberto; Andrade, Ricardo G.; de C. Victoria, Daniel; Bayma-Silva, Gustavo; Bolfe, Edson L.

    2015-10-01

    The southern region is responsible for 70% of rice production in Brazil. In this study, rice areas of Rio Grande do Sul were selected, using the land use classification, scale 1: 100,000, provided by Brazilian Institute of Geography and Statistics (IBGE). MODIS Images were used and meteorological data, available by National Institute of Meteorology (INMET). The period of analysis was crop season 2011/2012, October to March. To obtain evapotranspiration was applied agrometeorological-spectral model SAFER (Simple Algorithm For Retrieving Evapotranspiration). From the analysis of the results, on planting and cultivation period , the average evapotranspiration (ET) daily was 1.93 +/- 0.96 mm.day-1. In the vegetative development period of rice, the daily ET has achieved 4.94 mm.day-1, with average value 2,31+/- 0.97 mm.day-1. In the period of harvest, evapotranspiration daily average was 1.84 +/- 0.80 mm.day-1. From results obtained, the estimation of evapotranspiration from satellite images may assist in monitoring the culture during the cycle, assisting in estimates of water productivity and crop yield.

  9. Microbial, physical and chemical properties of irrigation water in rice fields of Southern Brazil

    Directory of Open Access Journals (Sweden)

    MARIA HELENA L.R. RECHE

    2016-03-01

    Full Text Available ABSTRACT This paper presents the results of the statistical analysis of microbiological, physical and chemical parameters related to the quality of the water used in rice fields in Southern Brazil. Data were collected during three consecutive crop years, within structure of a comprehensive monitoring program. The indicators used were: potential hydrogen, electrical conductivity, turbidity, nitrogen, phosphorus, potassium, calcium, total and fecal coliforms. Principal Component and Discriminant Analysis showed consistent differences between the water irrigation and drainage, as the temporal variation demonstrated a clear reduction in the concentration of most of the variables analyzed. The pattern of this reduction is not the same in the two regions - that is, the importance of each of the different variables in the observed differentiation is modified in two locations. These results suggested that the variations in the water quality utilized for rice irrigation was influenced by certain specific aspects of each rice region in South Brazilian - such as anthropic action or soil/climate conditions in each hydrographic basin.

  10. A 400-year phytolith-based reconstruction of wild rice (Zizania palustris) abundance from Mud Lake core sediments, Fond du Lac Band of Lake Superior Chippewa Reservation, Minnesota, USA.

    Science.gov (United States)

    Munoz, R.; Caylor, E.; Yost, C. L.; Drake, C.; Ladwig, J. L.; Myrbo, A.; Howes, T.

    2014-12-01

    Wild rice (Zizania palustris L.) is an aquatic grass with spiritual and subsistence significance to Native people of the Great Lakes region of North America. Mud Lake (Mashkiigwaagamaag), located on the Fond du Lac Band of Lake Superior Chippewa Reservation in Carlton County, Minnesota, USA, once supported an extensive population of wild rice (manoomin). However, early 20th century attempts to ditch and drain surrounding wetlands for landuse intensification severely altered the natural hydrological system that supports wild rice. Fond du Lac Resource Management (FDLRM) technicians are currently working to increase the wild rice population in Mud Lake. As part of these efforts, this phytolith study was undertaken to better understand how wild rice abundance has fluctuated over the past 400 years, with particular emphasis on the 19th and 20th centuries. Phytoliths are microscopic opal silica plant remains that are incorporated into soils and lake sediments after the plant-parts that contain them decay. Wild rice produces phytolith morphotypes that are unequivocally diagnostic. Mud Lake core MNMN-MUD11-1C-1P-1 (46°43'38.39"N, 92°42'2.45"W) was piston cored by LacCore (National Lacustrine Core Facility) and FDLRM technicians on 24 May 2011. Initial core descriptions, multi-sensor core logging, phytolith sampling and phytolith extractions were completed during the summer of 2014 at LacCore. Wild rice phytolith identification and quantification was conducted on twelve samples using brightfield microscopy at 400x magnification. Wild rice phytolith concentration values ranged from 68 to 2,300 phytoliths/cm3. Wild rice accumulation rates ranged from 9 to 383 phytoliths/ cm2/yr, peaking in 1952 AD. Wild rice abundance in Mud Lake appears to be influenced by a complex set of variables that include anthropogenic disturbance, climatic events and aquatic plant community succession.

  11. Synthesis and Gas Transport Properties of Hyperbranched Polyimide–Silica Hybrid/Composite Membranes

    OpenAIRE

    Masako Miki; Hideki Horiuchi; Yasuharu Yamada

    2013-01-01

    Hyperbranched polyimide–silica hybrids (HBPI–silica HBDs) and hyperbranched polyimide–silica composites (HBPI–silica CPTs) were prepared, and their general and gas transport properties were investigated to clarify the effect of silica sources and preparation methods. HBPI–silica HBDs and HBPI–silica CPTs were synthesized by two-step polymerization of A2 + B3 monomer system via polyamic acid as precursor, followed by hybridizing or blending silica sources. Silica components were incorporated b...

  12. The Effect of Commercial Rice Husk Ash Additives on the Porosity, Mechanical Properties, and Microstructure of Alumina Ceramics

    Directory of Open Access Journals (Sweden)

    Mohammed Sabah Ali

    2017-01-01

    Full Text Available A porous ceramic is made from composite materials which consist of alumina and commercial rice husk ash. This type of ceramics is obtained by mixing the commercial rice husk ash as a source of silica (SiO2 and a pore forming agent with alumina (Al2O3 powder. To obtain this type of ceramic, a solid-state technique is used with sintering at high temperature. This study also investigated the effects of the rice husk ash ratios on the mechanical properties, porosity, and microstructure. The results showed that, by increasing the content of the rice husk ash from 10 to 50 wt%, there is an increase in the porosity from 42.92% to 49.04%, while the mechanical properties decreased initially followed by an increase at 30 wt% and 50 wt%; the hardness at 20 wt% of the ash content was recorded at 101.90 HV1. When the ash content was increased to 30 wt% and 50 wt%, the hardness was raised to 150.92 HV1 and 158.93 HV1, respectively. The findings also revealed that the tensile and compressive strengths experienced a decrease at 10 wt% of the ash content and after that increase at 30 wt% and 50 wt% of rice husk ash. XRD analysis found multiple phases of ceramic formation after sintering for the different rice husk ash content.

  13. Modified Silica Nanofibers with Antibacterial Activity

    OpenAIRE

    Ivana Veverková; Irena Lovětinská-Šlamborová

    2016-01-01

    This study is focused on development of functionalized inorganic-organic nanofibrous material with antibacterial activity for wound dressing applications. The nanofibers combining poly(vinyl alcohol) and silica were produced by electrospinning from the sol and thermally stabilized. The PVA/silica nanofibers surface was functionalized by silver and copper nanoparticles to ensure antibacterial activity. It was proven that quantity of adsorbed silver and copper nanoparticles depends on process t...

  14. Distribution of arsenic and oxidative stress in mice after rice ingestion.

    Science.gov (United States)

    Souza, Juliana Maria Oliveira; Grotto, Denise; Batista, Bruno Lemos; Barbosa, Fernando

    2017-12-01

    This study evaluated the effects of rice naturally contaminated with arsenic (As) and the same As-species added as solubilized-salt on the redox state and the As distribution in male mice. The total As amount in the Brazilian polished rice used in this study was 169.81±6.12ngg-1. Indeed, the concentrations of As species were 40.77ngg-1 (arsenite, As3+), 65.71ngg-1 (dimethylarsinic acid, DMA), 11.90ngg-1 (monomethylarsonic acid, MMA), and 25.96ngg-1 (arsenate, As5+). In this sense, animals were randomly divided into seven groups with six mice per group: I) control: habitual food; II) rice I: diet containing 10% of rice naturally containing As (4.08μg As3+/kg diet, 6.57μg DMA/kg diet, 1.19μg MMA/kg diet, and 2.60μg As5+/kg diet); III) rice II: diet containing 20% of rice naturally containing As (8.15μg As3+/kg diet, 13.14μg DMA/kg diet, 2.38μg MMA/kg diet, and 5.19μg As5+/kg diet); IV) rice III: diet containing 40% of rice naturally containing As (16.31μg As3+/kg diet, 26.28μg DMA/kg diet, 4.76μg MMA/kg diet, and 10.38μg As5+/kg diet); V) spiked feed I: diet containing As species as solubilized-salt (concentration equivalent to group II); VI) spiked feed II: diet containing As species as solubilized-salt (concentration equivalent to group III); VII) spiked feed III: diet containing As species as solubilized-salt (concentration equivalent to group IV). The time of treatment was 100days. After euthanasia, it was observed an increase in total As concentration in tissue samples of groups treated with diet containing rice naturally contaminated and diet containing As species. For instance, the highest As concentrations (higher than 330ngg-1) was observed in the bladder of animals belonging to Rice II and III and spiked feed III groups. Furthermore, it was verified the highest As concentrations in bladder > hair > lung > kidney > liver > blood. We also observed the presence of DMA and As5+ in liver and kidneys. Regarding oxidative stress biomarkers, we

  15. Australian wild rice reveals pre-domestication origin of polymorphism deserts in rice genome.

    Science.gov (United States)

    Krishnan S, Gopala; Waters, Daniel L E; Henry, Robert J

    2014-01-01

    Rice is a major source of human food with a predominantly Asian production base. Domestication involved selection of traits that are desirable for agriculture and to human consumers. Wild relatives of crop plants are a source of useful variation which is of immense value for crop improvement. Australian wild rices have been isolated from the impacts of domestication in Asia and represents a source of novel diversity for global rice improvement. Oryza rufipogon is a perennial wild progenitor of cultivated rice. Oryza meridionalis is a related annual species in Australia. We have examined the sequence of the genomes of AA genome wild rices from Australia that are close relatives of cultivated rice through whole genome re-sequencing. Assembly of the resequencing data to the O. sativa ssp. japonica cv. Nipponbare shows that Australian wild rices possess 2.5 times more single nucleotide polymorphisms than in the Asian wild rice and cultivated O. sativa ssp. indica. Analysis of the genome of domesticated rice reveals regions of low diversity that show very little variation (polymorphism deserts). Both the perennial and annual wild rice from Australia show a high degree of conservation of sequence with that found in cultivated rice in the same 4.58 Mbp region on chromosome 5, which suggests that some of the 'polymorphism deserts' in this and other parts of the rice genome may have originated prior to domestication due to natural selection. Analysis of genes in the 'polymorphism deserts' indicates that this selection may have been due to biotic or abiotic stress in the environment of early rice relatives. Despite having closely related sequences in these genome regions, the Australian wild populations represent an invaluable source of diversity supporting rice food security.

  16. Comparative Study between Direct and Pseudomorphic Transformation of Rice Husk Ash into MFI-Type Zeolite.

    Science.gov (United States)

    Alyosef, Hallah Ahmad; Roggendorf, Hans; Schneider, Denise; Inayat, Alexandra; Welscher, Julia; Schwieger, Wilhelm; Münster, Tom; Kloess, Gert; Ibrahim, Suzan; Enke, Dirk

    2017-12-21

    Pre-shaped mesoporous amorphous rice husk ash (RHA) and MCM-41 derived from RHA as a silica source were transformed into MFI-type zeolites using two different structure-directing agents. Tetrapropylammonium hydroxide (TPAOH) was utilized as an alkali source for silica dissolution and structure control during the direct transformation of RHA into zeolite. A monopropylamine (PA)-containing alkaline solution (NaOH) was used for the pseudomorphic transformation of RHA or MCM-41 into zeolite. The hydrothermal conversion of RHA or MCM-41 into MFI-type zeolites was investigated as a function of reaction time at 175 °C. With PA as template, the crystallization took place inside and on the outer surface of RHA or MCM-41 without losing the original shape of the initial silica sources, while TPAOH led to the formation of conventional MFI-type zeolite crystals due to the complete dissolution of RHA. The final products were characterized by X-ray diffraction, nitrogen adsorption, scanning electron microscopy, and optical emission spectroscopy.

  17. Grassy Silica Nanoribbons and Strong Blue Luminescence

    Science.gov (United States)

    Wang, Shengping; Xie, Shuang; Huang, Guowei; Guo, Hongxuan; Cho, Yujin; Chen, Jun; Fujita, Daisuke; Xu, Mingsheng

    2016-09-01

    Silicon dioxide (SiO2) is one of the key materials in many modern technological applications such as in metal oxide semiconductor transistors, photovoltaic solar cells, pollution removal, and biomedicine. We report the accidental discovery of free-standing grassy silica nanoribbons directly grown on SiO2/Si platform which is commonly used for field-effect transistors fabrication without other precursor. We investigate the formation mechanism of this novel silica nanostructure that has not been previously documented. The silica nanoribbons are flexible and can be manipulated by electron-beam. The silica nanoribbons exhibit strong blue emission at about 467 nm, together with UV and red emissions as investigated by cathodoluminescence technique. The origins of the luminescence are attributed to various defects in the silica nanoribbons; and the intensity change of the blue emission and green emission at about 550 nm is discussed in the frame of the defect density. Our study may lead to rational design of the new silica-based materials for a wide range of applications.

  18. Grazers: biocatalysts of terrestrial silica cycling.

    Science.gov (United States)

    Vandevenne, Floor Ina; Barão, Ana Lúcia; Schoelynck, Jonas; Smis, Adriaan; Ryken, Nick; Van Damme, Stefan; Meire, Patrick; Struyf, Eric

    2013-12-07

    Silica is well known for its role as inducible defence mechanism countering herbivore attack, mainly through precipitation of opaline, biogenic silica (BSi) bodies (phytoliths) in plant epidermal tissues. Even though grazing strongly interacts with other element cycles, its impact on terrestrial silica cycling has never been thoroughly considered. Here, BSi content of ingested grass, hay and faeces of large herbivores was quantified by performing multiple chemical extraction procedures for BSi, allowing the assessment of chemical reactivity. Dissolution experiments with grass and faeces were carried out to measure direct availability of BSi for dissolution. Average BSi and readily soluble silica numbers were higher in faeces as compared with grass or hay, and differences between herbivores could be related to distinct digestive strategies. Reactivity and dissolvability of BSi increases after digestion, mainly due to degradation of organic matrices, resulting in higher silica turnover rates and mobilization potential from terrestrial to aquatic ecosystems in non-grazed versus grazed pasture systems (2 versus 20 kg Si ha(-1) y(-1)). Our results suggest a crucial yet currently unexplored role of herbivores in determining silica export from land to ocean, where its availability is linked to eutrophication events and carbon sequestration through C-Si diatom interactions.

  19. Microporous Silica Based Membranes for Desalination

    Directory of Open Access Journals (Sweden)

    João C. Diniz da Costa

    2012-09-01

    Full Text Available This review provides a global overview of microporous silica based membranes for desalination via pervaporation with a focus on membrane synthesis and processing, transport mechanisms and current state of the art membrane performance. Most importantly, the recent development and novel concepts for improving the hydro-stability and separating performance of silica membranes for desalination are critically examined. Research into silica based membranes for desalination has focussed on three primary methods for improving the hydro-stability. These include incorporating carbon templates into the microporous silica both as surfactants and hybrid organic-inorganic structures and incorporation of metal oxide nanoparticles into the silica matrix. The literature examined identified that only metal oxide silica membranes have demonstrated high salt rejections under a variety of feed concentrations, reasonable fluxes and unaltered performance over long-term operation. As this is an embryonic field of research several target areas for researchers were discussed including further improvement of the membrane materials, but also regarding the necessity of integrating waste or solar heat sources into the final process design to ensure cost competitiveness with conventional reverse osmosis processes.

  20. Functional genomics strategies with transposons in rice

    NARCIS (Netherlands)

    Greco, R.

    2003-01-01

    Rice is a major staple food crop and a recognizedmonocotylenedousmodel plant from which gene function discovery is projected to contribute to improvements in a variety of cereals like wheat and maize. The recent release of rough drafts of the rice genome sequence for public

  1. PICTORIAL INTERLUDES Flake-shaped rice bodies

    African Journals Online (AJOL)

    1. Cheung HS, Ryan LM, Kozin F, McCarty DJ. Synovial origins of rice bodies in joint fluid. Arthritis. Rheum 1980;23:72-76. 2. Popert AJ, Scott DL, Wainwright AC, Walton KW, Williamson N, Chapman JH. Frequency of occur- rence, mode of development, and significance of rice bodies in rheumatoid joints. Ann Rheum Dis.

  2. Influence of intermittent irrigation, red rice biotype, and rice grain type on outcrossing between red rice and imidazolinone-resistant rice

    Science.gov (United States)

    Whether outcrossing rates between red rice and imazethapyr resistant rice are affected as a function of irrigation management is unclear. Potentially, differences between conventionally-flooded (CNV) and intermittently flooded (INT) systems could affect plant water deficits, as well as vegetative a...

  3. Transgenic strategies for improving rice disease resistance

    African Journals Online (AJOL)

    STORAGESEVER

    2009-05-04

    May 4, 2009 ... Review. Transgenic strategies for improving rice disease resistance. Huijuan Zhang, Guojun Li, Wei Li and Fengming Song*. State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University-Huajiachi Campus, Hangzhou,. Zhejiang 310029, P.R. .... In RTBV-ODs2 line, RTBV DNA.

  4. Adoption of Recommended Rice Production Practices among ...

    African Journals Online (AJOL)

    User

    influenced adoption of recommended rice production practices by women rice farmers in the study area. Constraints hindering adoption of. RRPPs were unavailability of credit facilities, poor marketing system and unstable price, and inadequate extension contacts. It was recommended that government should ensure that ...

  5. Novel gene expression tools for rice biotechnology

    Science.gov (United States)

    Biotechnology is an effective and important method of improving both quality and agronomic traits in rice. We are developing novel molecular tools for genetic engineering, with a focus on developing novel transgene expression control elements (i.e. promoters) for rice. A suite of monocot grass promo...

  6. FLUORIDE LEVELS IN COMMERCIALLY AVAILABLE RICE IN ...

    African Journals Online (AJOL)

    Preferred Customer

    2013-05-05

    May 5, 2013 ... shattering-prone Oryza glaberrima. It contains 2% more protein than their African or Asian parents. It is taller than most rice, making harvesting easier, pest resistant and tolerant to drought and infertile soils better than Asian varieties [18]. Rice is a cereal foodstuff which forms an important part of the diet of ...

  7. Grain Unloading Of Arsenic Species In Rice

    Science.gov (United States)

    Rice (Oryza sativa) is the staple food for over half the world's population yet may represent a significant dietary source of inorganic arsenic (As), a nonthreshold, class 1 human carcinogen. Rice grain As is dominated by the inorganic species, and the organic species dim...

  8. Rice aroma and flavor: a literature review.

    Science.gov (United States)

    Descriptive sensory analysis has identified over a dozen different aromas and flavors in rice. Instrumental analyses have found over 200 volatile compounds present in rice. However, after over 30 years of research, little is known about the relationships between the numerous volatile compounds and a...

  9. Soil quality assessment in rice production systems

    NARCIS (Netherlands)

    Rodrigues de Lima, A.C.

    2007-01-01

    In the state of Rio Grande do Sul, Brazil, rice production is one of the most important regional activities. Farmers are concerned that the land use practices for rice production in the Camaquã region may not be sustainable because of detrimental effects on soil quality. The study presented in this

  10. Impact of Colloidal Silica on Silicone Oil-Silica Mixed Antifoams

    Science.gov (United States)

    Yuan, Zheng

    Antifoams are utilized as an industrial additive to control undesired foam during processing. This study focuses on the impact of silica on the antifoam stability. Antifoam stability refers to the ability to maintain efficiency in foam destruction after prolonged shelf storage. Common antifoams are a mixture of hydrophobic silica particles and silicone oil. Based on the general mechanisms of antifoam action discussed in Chapter 1, silica particles play a significant role in foam destruction. Silica particles contribute to foam control by facilitating the entry and the penetration depth of oil-silica globules into surfactant-water films (foam bubble walls). The size, morphology and hydrophobicity of silica can be manipulated to generate optimal antifoam globules. For example, the two silicas with good shelf life performance (8375 and 9512) had the largest silica particles and both showed a tendency to aggregate in toluene solution. We conclude that improved shelf life is related to the propensity of PDMS oil to adsorb on silica, which leads to aggregation and particle size increase. We measured the time-evolution of dynamic light scattering (DLS) from 3-vol% antifoam dissolved in toluene (Chapter 2). For the sample with the largest hydrodynamic radius (9512) the scattered intensity decreased significantly after applying ultrasonic dispersion. Decreasing intensity also occurred for 8375 albeit at later times. The decrease of intensity is attributed to the growth and precipitation of oil-silica globules. The concentration dependence of light scattering confirmed the growth-precipitation hypothesis. FT-IR (Chapter 3) was consistent with precipitation due to oil adsorption, but the data were not definitive. Chapter 4 examines the time-evolution of silica structures by static light scattering and X-ray scattering. The combined data are consistent with a hierarchical structure for silica. Agglomeration occurred fastest for 9512, which is consistent with DLS observations

  11. Transport of colloidal silica in unsaturated sand: Effect of charging properties of sand and silica particles.

    Science.gov (United States)

    Fujita, Yosuke; Kobayashi, Motoyoshi

    2016-07-01

    We have studied the transport of colloidal silica in various degrees of a water-saturated Toyoura sand column, because silica particles are widely used as catalyst carriers and abrasive agents, and their toxicity is reported recently. Since water-silica, water-sand, and air-water interfaces have pH-dependent negative charges, the magnitude of surface charge was controlled by changing the solution pH. The results show that, at high pH conditions (pH 7.4), the deposition of colloidal silica to the sand surface is interrupted and the silica concentration at the column outlet immediately reaches the input concentration in saturated conditions. In addition, the relative concentration of silica at the column outlet only slightly decreases to 0.9 with decreasing degrees of water saturation to 38%, because silica particles are trapped in straining regions in the soil pore and air-water interface. On the other hand, at pH 5 conditions (low pH), where sand and colloid have less charge, reduced repulsive forces result in colloidal silica attaching onto the sand in saturated conditions. The deposition amount of silica particles remarkably increases with decreasing degrees of water saturation to 37%, which is explained by more particles being retained in the sand column associated with the air-water interface. In conclusion, at higher pH, the mobility of silica particles is high, and the air-water interface is inactive for the deposition of silica. On the other hand, at low pH, the deposition amount increases with decreasing water saturation, and the particle transport is inhibited. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Image - Rice Grain Scanner: a three-dimensional fully automated assessment of grain size and quality traits

    Directory of Open Access Journals (Sweden)

    Rubens Marschalek

    2016-12-01

    Full Text Available The Image is a scanner developed as a grain classifier for quality control at the rice industry based on Brazilian official norms. It orders the dehulled grains ensuring that each grain would pass individually, in free fall, while the grain is analysed from different sides, covering its whole surface. It ensures a precise three-dimensional measurement of grain size, chalkiness, defects of the grain, milling quality, given out a total of 39 traits/classes/defects/values, which are sent to a excel Microsoft spreadsheet. This is managed through a digital platform which analysis routine and layout were developed and designed by Selgron and Epagri to fit the needs of research. The scanner and its software reach outputs that enhance rice breeding efficiency for grain quality, performing it faster, precisely and with a high-throughput phenotyping than ever before, especially interesting in very early breeding generations.

  13. Dinitrogen fixation of rice-Klebsiella associations

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, I.D.; Fujii, T.; Sano, Y.; Komagata, K.; Yoneyama, T.; Iyama, S.; Hirota, Y.

    N/sub 2/ fixation by Klebsiella oxytoca strain NG13, isolated from the rhizosphere of a rice (Oryza sativa L.) plant, in association with Indica type rice strain, C5444 is reported. The C/sub 2/H/sub 2/-reduction assays, biomass measurements, N content determinations, and /sup 15/N isotopic dilution assays indicated that inoculation of C5444 with NG13 resulted in a 6% increase of total plant+soil N content, and a 19% /sup 15/N isotopic dilution of plant N after 120 days of cultivation. Our results demonstrated significant levels of N/sub 2/ fixation by K. oxytoca when associated with rice. By optimizing such rice plant-bacterial N/sub 2/ fixation capacity, the N uptake by rice could be enhanced.

  14. Rice epigenomics and epigenetics: challenges and opportunities.

    Science.gov (United States)

    Chen, Xiangsong; Zhou, Dao-Xiu

    2013-05-01

    During recent years rice genome-wide epigenomic information such as DNA methylation and histone modifications, which are important for genome activity has been accumulated. The function of a number of rice epigenetic regulators has been studied, many of which are found to be involved in a diverse range of developmental and stress-responsive pathways. Analysis of epigenetic variations among different rice varieties indicates that epigenetic modification may lead to inheritable phenotypic variation. Characterizing phenotypic consequences of rice epigenomic variations and the underlining chromatin mechanism and identifying epialleles related to important agronomic traits may provide novel strategies to enhance agronomically favorable traits and grain productivity in rice. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Silica ecosystem for synergistic biotransformation

    Science.gov (United States)

    Mutlu, Baris R.; Sakkos, Jonathan K.; Yeom, Sujin; Wackett, Lawrence P.; Aksan, Alptekin

    2016-06-01

    Synergistical bacterial species can perform more varied and complex transformations of chemical substances than either species alone, but this is rarely used commercially because of technical difficulties in maintaining mixed cultures. Typical problems with mixed cultures on scale are unrestrained growth of one bacterium, which leads to suboptimal population ratios, and lack of control over bacterial spatial distribution, which leads to inefficient substrate transport. To address these issues, we designed and produced a synthetic ecosystem by co-encapsulation in a silica gel matrix, which enabled precise control of the microbial populations and their microenvironment. As a case study, two greatly different microorganisms: Pseudomonas sp. NCIB 9816 and Synechococcus elongatus PCC 7942 were encapsulated. NCIB 9816 can aerobically biotransform over 100 aromatic hydrocarbons, a feat useful for synthesis of higher value commodity chemicals or environmental remediation. In our system, NCIB 9816 was used for biotransformation of naphthalene (a model substrate) into CO2 and the cyanobacterium PCC 7942 was used to provide the necessary oxygen for the biotransformation reactions via photosynthesis. A mathematical model was constructed to determine the critical cell density parameter to maximize oxygen production, and was then used to maximize the biotransformation rate of the system.

  16. Rice water in treatment of infantile gastroenteritis.

    Science.gov (United States)

    Wong, H B

    1981-07-11

    In Singapore the World Health Organization's (WHO's) oral electrolyte solution for the treatment of infantile gastroenteritis has been used for 6 years and rice water has been used for 8 years. The rice water is the water used in preparing boiled rice or congee and is a slightly starchy solution. As the impression was that rice water was as effective as or even better than the oral electrolyte solution, a trial was conducted of the 2 solutions in babies with gastroenteritis admitted to the Department of Pediatrics of the National University of Singapore. Alternate cases were assigned consecutively to the oral electrolyte solution or to rice water. There were 63 patients on oral electrolyte and 67 on rice water. Milk was totally withdrawn for 24 hours after admission and the babies were put on 1 or the other oral solution. Intravenous 3.75% glucose and 0.23% saline was given at the same time to babies considered to be more dehydrated. On day 2, quarter strength powdered milk was given, followed by half strength on day 3, three-quarters strength on day 4, and full strength on day 5. Electrolyte and urea values were compared, both for "drip" versus "no drip" within oral treatment groups and between electrolyte solution and rice water groups (20 comparisons altogether). There were only 3 significant differences, and these might be explained by the intravenous drip and by the better water absorption from rice water than from the oral electrolyte solution. The most obvious difference in the 2 groups was in the effect on diarrhea (stools/day). Rice water cut down the number of stools more effectively than did oral electrolyte solution. No patient died, and there were no pathological sequelae in any of the 130 patients. Rice water can be tried as a more practical alternative to oral electrolyte solutions since there are problems with providing oral elecrolyte solutions to all babies with diarrhea in the developing countries and ensuring sterility.

  17. Determinants of adoption and productivity of improved rice varieties ...

    African Journals Online (AJOL)

    The study examines the status of adoption of improved rice varieties and its impact on rice production among smallholder farmers in southwestern Nigeria. Data for this study were generated from a farm survey of rice farmers selected by multi-stage sampling technique in two of the rice producing states of the region.

  18. Signatures of adaptation in the weedy rice genome

    Science.gov (United States)

    Weedy rice is a common problem of by product of domestication that has evolved multiple times from cultivated and wild rice relatives. Here we use whole genome sequences to examine the origin and adaptation of the two major US weedy red rice strains, with a comparison to Chinese weedy red rice. We f...

  19. Rice Genome Research: Current Status and Future Perspectives

    OpenAIRE

    Bin Han; Qifa Zhang

    2008-01-01

    Rice ( L.) is the leading genomics system among the crop plants. The sequence of the rice genome, the first cereal plant genome, was published in 2005. This review summarizes progress made in rice genome annotations, comparative genomics, and functional genomics researches. It also maps out the status of rice genomics globally and provides a vision of future research directions and resource building.

  20. Cooking and Eating Quality of Rice Yellow Mottle Virus Resistant ...

    African Journals Online (AJOL)

    physico-chemical behaviour of the rice grain. Physical characteristics .... combined influence of the different rating parameters of the seven rice ... Cooking and Eating Quantity of Rice Yellow Mottle 197. Table 1: Grain quality characteristics of the tested rice genotypes. Line / Parent. Grain. Length/. Opacity. Amylose. Gel. Gel.

  1. Does African catfish ( Clarias gariepinus ) affect rice in integrated ...

    African Journals Online (AJOL)

    An experiment was conducted for 98 days in the Lake Victoria Basin to investigate the interactions of fish and rice growth performance in rice paddies. The experiment was laid out in a split-plot design, with rice cultivar as the main plot and method of rice-fish culture as the sub-plot. Treatments consisted of two levels of ...

  2. Economic survey of rice marketing in Anambra state, Nigeria ...

    African Journals Online (AJOL)

    The results of the analysis show that old people who are mostly illiterate but highly experienced engaged in rice marketing business. Furthermore, there is a significant difference in the marketing prices of processed and unprocessed rice as well as stored and unstored rice. However, a greater percentage of rice marketers ...

  3. Significance of rice sheath photosynthesis: Yield determination by ...

    African Journals Online (AJOL)

    Using high-yielding hybrid rice Liangyopeijiu (LYP9), its male parent 9311 and hybrid rice Shanyou 63 (SY63) as the experimental materials, the photosynthesis of rice sheath was studied by 14C radio-autography. The results showed that rice sheath could trap sunlight and produce photosynthates, and these ...

  4. Golden Rice is an effective source for vitamin A

    Science.gov (United States)

    Genetically engineered "Golden Rice" contains up to 35 ug Beta-carotene per gram of rice. It is important to determine the vitamin A equivalency of Golden Rice Beta-carotene to project the potential effect of this biofortified grain in rice-consuming populations that commonly exhibit low vitamin A s...

  5. Identification of Some Degradation Products of Golden Rice Beta- carotene

    Science.gov (United States)

    Golden Rice (GR2) is genetically modified rice, which can contain as high as 37 ug of beta-carotene per g of dry rice. It was developed to combat vitamin A deficiency (VAD), a major malnutrition problem in many parts of the developing world, especially in South and South Eastern Asia, where rice is ...

  6. The economic power of the Golden Rice opposition

    NARCIS (Netherlands)

    Wesseler, J.H.H.; Zilberman, D.

    2014-01-01

    Vitamin A enriched rice (Golden Rice) is a cost-efficient solution that can substantially reduce health costs. Despite Golden Rice being available since early 2000, this rice has not been introduced in any country. Governments must perceive additional costs that overcompensate the benefits of the

  7. Rice field for the treatment of pond aquaculture effluents | Wang ...

    African Journals Online (AJOL)

    We conducted an experiment to evaluate the efficiency of rice fields in treating pond aquaculture effluent and its responses to different fertilizer treatments. Four treatments was considered in the experiment: no rice planted as the control (CT); rice planted and no fertilizer input (RE); rice planted and a rate of approximately ...

  8. genetic analysis of resistance to rice bacterial blight in uganda

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    Advances in rice genetics. Supplement to rice genetics IV. Proceedings of the Fourth. International Rice Genetics Symposium, 22-. 27 October 2000. IRRI. Los Baños, Philippines. Lee, K.S., Rasabandith, S., Angeles, E.R. and. Khush, G.S. 2003. Inheritance of resistance to bacterial blight in 21cultivars of rice. Phytopathology ...

  9. Microstructure Assessment of Metakaolin Based-Geopolymers Produced with Alternative Silica Sources Exposed to High Temperatures

    Directory of Open Access Journals (Sweden)

    Villaquirán-Caicedo Mónica Alejandra

    2015-01-01

    Full Text Available Ceramic materials more environment friendly and with similar or even better performance than traditional ones can be produced by alkali activation of natural minerals, wastes or industrial by-products. The present study assesses the effect of exposure at 600° and 1200°C of a MK-based geopolymers. Rice husk ash (RHA and silica fume were modified chemically in order to obtain an alternative alkali activator. Exposure to elevated temperatures leads to dehydration of the reaction products and structural reorganization associated with the crystallization of the gel to leucite (KAlSi2O6 and kalsilite (KAlSiO4. The structural changes associated with the thermal treatment also promote a densification and reduction of porosity. The unreacted MK particles embedded into the geopolymeric gel lead to the formation of mullite (2Al2O3 × SiO2 after the thermal treatment at 1200°C.

  10. Effects of silica content on the formation and morphology of ENR/PVC/Silica composites beads

    Science.gov (United States)

    Abdullah, Nurul Amni; Tahiruddin, Nordiana Suhada Mohmad; Othaman, Rizafizah

    2017-05-01

    The effects of silica content in preparing silica-filled epoxidized natural rubber/polyvinyl chloride (ENR/PVC) beads were investigated. ENR/PVC matrix blend used was of composition 60% (ENR50) and 40% (PVC) by weight. The matrix blend was then dissolved in tetrahydrofuran (THF) by sol-gel technique prior to addition of silica fume as filler at varying amounts up to 25 wt% of the matrix mass. The composites beads were formed via phase inversion method by dropping the polymeric solution into a non-solvent. The size and shape were improved by adding in an increased amount of silica. Morphological studies showed distinct features of beads' surface in terms of homogeneity of silica particle distribution and presence of agglomerations and voids within the ENR/PVC matrix. Formation of silica network was apparent on the bead at 25 wt% silica content. The bead formation was found to be significantly affected by the silica loading in the ENR/PVC solution.

  11. The Management of Silica in Los Alamos National Laboratory Tap Water - A Study of Silica Solubility

    Energy Technology Data Exchange (ETDEWEB)

    Wohlberg, C.; Worland, V.P.; Kozubal, M.A.; Erickson, G.F.; Jacobson, H.M.; McCarthy, K.T.

    1999-07-01

    Well water at Los Alamos National Laboratory (LANL) has a silica (SiO{sub 2}) content of 60 to 100 mg/L, with 4 mg/L of magnesium, 13 mg/L calcium and lesser concentrations of other ions. On evaporation in cooling towers, when the silica concentration reaches 150 to 220 mg/L, silica deposits on heat transfer surfaces. When the high silica well water is used in the reprocessing of plutonium, silica remains in solution at the end of the process and creates a problem of removal from the effluent prior to discharge or evaporation. The work described in this Report is divided into two major parts. The first part describes the behavior of silica when the water is evaporated at various conditions of pH and in the presence of different classes of anions: inorganic and organic. In the second part of this work it was found that precipitation (floccing) of silica was a function of solution pH and mole ratio of metal to silica.

  12. RPAN: rice pan-genome browser for ∼3000 rice genomes.

    Science.gov (United States)

    Sun, Chen; Hu, Zhiqiang; Zheng, Tianqing; Lu, Kuangchen; Zhao, Yue; Wang, Wensheng; Shi, Jianxin; Wang, Chunchao; Lu, Jinyuan; Zhang, Dabing; Li, Zhikang; Wei, Chaochun

    2017-01-25

    A pan-genome is the union of the gene sets of all the individuals of a clade or a species and it provides a new dimension of genome complexity with the presence/absence variations (PAVs) of genes among these genomes. With the progress of sequencing technologies, pan-genome study is becoming affordable for eukaryotes with large-sized genomes. The Asian cultivated rice, Oryza sativa L., is one of the major food sources for the world and a model organism in plant biology. Recently, the 3000 Rice Genome Project (3K RGP) sequenced more than 3000 rice genomes with a mean sequencing depth of 14.3×, which provided a tremendous resource for rice research. In this paper, we present a genome browser, Rice Pan-genome Browser (RPAN), as a tool to search and visualize the rice pan-genome derived from 3K RGP. RPAN contains a database of the basic information of 3010 rice accessions, including genomic sequences, gene annotations, PAV information and gene expression data of the rice pan-genome. At least 12 000 novel genes absent in the reference genome were included. RPAN also provides multiple search and visualization functions. RPAN can be a rich resource for rice biology and rice breeding. It is available at http://cgm.sjtu.edu.cn/3kricedb/ or http://www.rmbreeding.cn/pan3k. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  13. Can the co-cultivation of rice and fish help sustain rice production?

    Science.gov (United States)

    Hu, Liangliang; Zhang, Jian; Ren, Weizheng; Guo, Liang; Cheng, Yongxu; Li, Jiayao; Li, Kexin; Zhu, Zewen; Zhang, Jiaen; Luo, Shiming; Cheng, Lei; Tang, Jianjun; Chen, Xin

    2016-06-01

    Because rice feeds half of the world’s population, a secure global food supply depends on sustainable rice production. Here we test whether the co-cultivation of rice and fish into one “rice-fish system” (RFS; fish refers to aquatic animals in this article) could help sustain rice production. We examined intensive and traditional RFSs that have been widely practiced in China. We found that rice yields did not decrease when fish yield was below a threshold value in each intensive RFS. Below the thresholds, moreover, fish yields in intensive RFSs can be substantially higher than those in traditional RFS without reducing rice yield. Relative to rice monoculture, the use of fertilizer-nitrogen and pesticides decreased, and the farmers’ net income increased in RFSs. The results suggest that RFSs can help sustain rice production, and suggest that development of co-culture technologies (i.e. proper field configuration for fish and rice) is necessary to achieve the sustainability.

  14. Physicochemical and Antioxidant Properties of Rice Bran Oils Produced from Colored Rice Using Different Extraction Methods.

    Science.gov (United States)

    Mingyai, Sukanya; Kettawan, Aikkarach; Srikaeo, Khongsak; Singanusong, Riantong

    2017-06-01

    This study investigated the physicochemical and antioxidant properties of rice bran oil (RBO) produced from the bran of three rice varities; Khao Dawk Mali 105 (white rice), Red Jasmine rice (red rice) and Hom-nin rice (black rice) using three extraction methods including cold-press extraction (CPE), solvent extraction (SE) and supercritical CO2 extraction (SC-CO2). Yields, color, acid value (AV), free fatty acid (FFA), peroxide value (PV), iodine value (IV), total phenolic compound (TPC), γ-oryzanol, α-tocopherol and fatty acid profile were analyzed. It was found that the yields obtained from SE, SC-CO2 and CPE extractions were 17.35-20.19%, 14.76-18.16% and 3.22-6.22%, respectively. The RBO from the bran of red and black rice samples exhibited high antioxidant activities. They also contained higher amount of γ-oryzanol and α-tocopherol than those of white rice sample. In terms of extraction methods, SC-CO2 provided better qualities of RBO as evidenced by their physicochemical and antioxidant properties. This study found that RBO produced from the bran of black rice samples using SC-CO2 extraction method showed the best physicochemical and antioxidant properties.

  15. Passages on Brazilian scientific cinema.

    Science.gov (United States)

    de Almeida, Jane; da Silva, Cicero Inacio; Suppia, Alfredo; Stalbaum, Brett

    2017-07-01

    The article examines the conditions of production and recognition of scientific cinema in Brazil by comparing three distinct moments and contexts: the first moment takes place in the nineteenth century, and it is related to the contribution of a Brazilian astronomer otherwise little known to Brazilian film scholars, the second addresses Benedito Junqueira Duarte's voluminous mid-twentieth-century filmography, and the third moment documents recent scientific film experiences within ultra high resolution movies transmitted over photonic networks. Future trajectories for aesthetic concerns and practical issues such as the archiving of ultra high definition cinema are usefully informed by these histories of scientific cinema, even as a current generation of multidisciplinary teams including scientists, filmmakers, computer scientists, and network engineers reinvent, rediscover, and necessarily expand the scientific cinema toward concerns of real time collaboration and teaching.

  16. Comparative Investigation on Thermal Insulation of Polyurethane Composites Filled with Silica Aerogel and Hollow Silica Microsphere.

    Science.gov (United States)

    Liu, Chunyuan; Kim, Jin Seuk; Kwon, Younghwan

    2016-02-01

    This paper presents a comparative study on thermal conductivity of PU composites containing open-cell nano-porous silica aerogel and closed-cell hollow silica microsphere, respectively. The thermal conductivity of PU composites is measured at 30 degrees C with transient hot bridge method. The insertion of polymer in pores of silica aerogel creates mixed interfaces, increasing the thermal conductivity of resulting composites. The measured thermal conductivity of PU composites filled with hollow silica microspheres is estimated using theoretical models, and is in good agreement with Felske model. It appears that the thermal conductivity of composites decreases with increasing the volume fraction (phi) when hollow silica microsphere (eta = 0.916) is used.

  17. Synthesis and Characterization of Bionanoparticle-Silica Composites and Mesoporous Silica with Large Pores

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Z.; Yang, L.; Kabisatpathy, S.; He, J.; Lee, A.; Ron, J.; Sikha, G.; Popov, B.N.; Emrick, T.; Russell, T. P.; Wang. Q.

    2009-03-24

    A sol-gel process has been developed to incorporate bionanoparticles, such as turnip yellow mosaic virus, cowpea mosaic virus, tobacco mosaic virus, and ferritin into silica, while maintaining the integrity and morphology of the particles. The structures of the resulting materials were characterized by transmission electron microscopy, small angle X-ray scattering, and N{sub 2} adsorption-desorption analysis. The results show that the shape and surface morphology of the bionanoparticles are largely preserved after being embedded into silica. After removal of the bionanoparticles by calcination, mesoporous silica with monodisperse pores, having the shape and surface morphology of the bionanoparticles replicated inside the silica, was produced,. This study is expected to lead to both functional composite materials and mesoporous silica with structurally well-defined large pores.

  18. Silica-based cationic bilayers as immunoadjuvants

    Directory of Open Access Journals (Sweden)

    Carmona-Ribeiro Ana M

    2009-01-01

    Full Text Available Abstract Background Silica particles cationized by dioctadecyldimethylammonium bromide (DODAB bilayer were previously described. This work shows the efficiency of these particulates for antigen adsorption and presentation to the immune system and proves the concept that silica-based cationic bilayers exhibit better performance than alum regarding colloid stability and cellular immune responses for vaccine design. Results Firstly, the silica/DODAB assembly was characterized at 1 mM NaCl, pH 6.3 or 5 mM Tris.HCl, pH 7.4 and 0.1 mg/ml silica over a range of DODAB concentrations (0.001–1 mM by means of dynamic light scattering for particle sizing and zeta-potential analysis. 0.05 mM DODAB is enough to produce cationic bilayer-covered particles with good colloid stability. Secondly, conditions for maximal adsorption of bovine serum albumin (BSA or a recombinant, heat-shock protein from Mycobacterium leprae (18 kDa-hsp onto DODAB-covered or onto bare silica were determined. At maximal antigen adsorption, cellular immune responses in vivo from delayed-type hypersensitivity reactions determined by foot-pad swelling tests (DTH and cytokines analysis evidenced the superior performance of the silica/DODAB adjuvant as compared to alum or antigens alone whereas humoral response from IgG in serum was equal to the one elicited by alum as adjuvant. Conclusion Cationized silica is a biocompatible, inexpensive, easily prepared and possibly general immunoadjuvant for antigen presentation which displays higher colloid stability than alum, better performance regarding cellular immune responses and employs very low, micromolar doses of cationic and toxic synthetic lipid.

  19. Consumer Preferences and Buying Criteria in Rice: A Study to Identify Market Strategy for Thailand Jasmine Rice Export

    NARCIS (Netherlands)

    Suwannaporn, P.; Linnemann, A.R.

    2008-01-01

    Rice consumption per capita in many Asian countries decreased, but it is consumed more in non-rice-eating countries. This study aimed to investigate consumer preferences and attitudes toward Jasmine rice among consumers in target rice export countries to identify opportunities and strategic

  20. Brands Repositioning: Brazilian case studies

    OpenAIRE

    Serralvo, Francisco Antonio; Furrier, Márcio Tadeu

    2008-01-01

    Based on the assumption of the increasing relevance of both brand positioning and equity in the context of marketing management in competitive environments, the objective of this work was to deepen the existing knowledge on the brand repositioning process. Four theoretical models of reference obtained after literature review supported the empiric verification represented by content analysis of six reports (cases) of Brazilian brands repositioning experiences awarded with the “Top of Marketing...

  1. Brazilian Participation in World War II

    Science.gov (United States)

    2006-12-15

    internal rebellions and secessionist movements such as the Canudos rebellion in 1897 and 1898 in Bahia province. As a 2 result, the Brazilian Army...Brazilian Army would play an important role in ending this dictatorship. Brazil had accepted large numbers of Italian and German immigrants for more than...including the Brazilian Armed Forces. They had a significant influence on decision makers. In the 1930s, German immigrants numbered more than 900,000 and

  2. Brazilian Studies Then and Now

    Directory of Open Access Journals (Sweden)

    Anthony Pereira

    2012-09-01

    Full Text Available In 1912 the Brazilian diplomat and scholar Manuel de Oliveira Lima gave six lectures at Stanford University that encapsulated his views of what we now call Brazilian Studies. This article summarizes Oliveira Lima’s lectures. It then points out three aspects of Oliveira Lima’s worldview that are problematic from the perspective of the twenty-first century: his Eurocentrism; the unproblematic nature of the nation-state in his thinking; and his largely negative view of Brazil’s racial heritage. The third part of the essay analyzes three aspects of Oliveira Lima’s lectures that are still contemporary. These are the need to establish an adequate comparative context for the study of Brazil; the difficulty of justifying an academic discipline that revolves around the study of a single country; and the challenge of uniting disparate and specialized disciplines in order to appreciate Brazil’s complexity and trajectory in the modern world. In the conclusion, some guidelines for maintaining Brazilian Studies as a vibrant field are suggested.

  3. Seed wintering and deterioration characteristics between weedy and cultivated rice

    OpenAIRE

    Baek, Jung-Sun; Chung, Nam-Jin

    2012-01-01

    Background Incidences of weedy rice continuously occurred in paddy fields because its shattering seeds were able to over-winter. In this research, the seed deterioration of weedy rice was investigated compared with cultivated rice, and the wintering characteristics of these two types of rice were investigated with the field wintering test, freezing resistance test, and accelerated aging test. Results For the wintering test, the seeds of weedy rice were placed on the soil surface of a paddy wi...

  4. COMPARATIVE PERFORMANCE OF A LOCALLY DEVELOPED VOTEX RICE FAN THRESHER

    OpenAIRE

    Dauda, S.M.; A. U. Dzivama

    2008-01-01

    The efforts to discover and make optimal and effective use of locally developed rice thresher as substitute for imported rice threshers form the focus of this paper. A locally developed rice thresher was compared with an imported Votex rice fan fromHolland.  The study was based on threshing efficiency, cleaning efficiency, total grain losses, grain recovery range, capacity utilization and threshing intensity. Three popular rice varieties, Faro 51, Faro 29 and Faro 21 were used to evaluate the...

  5. Structural Analysis of Alkaline Pretreated Rice Straw for Ethanol Production

    Directory of Open Access Journals (Sweden)

    Paripok Phitsuwan

    2017-01-01

    Full Text Available Rice straw (RS is an abundant, readily available agricultural waste, which shows promise as a potential feedstock for Asian ethanol production. To enhance release of glucose by enzymatic hydrolysis, RS was pretreated with aqueous ammonia (27% w/w at two pretreatment temperatures: room temperature and 60°C. Statistical analysis indicated similarity of enzymatic glucose production at both pretreatment temperatures after 3-day incubation. Chemical composition, FTIR, and EDX analyses confirmed the retention of glucan and xylan in the pretreated solid, but significant reduction of lignin (60.7% removal and silica. SEM analysis showed the disorganized surfaces and porosity of the pretreated RS fibers, thus improving cellulose accessibility for cellulase. The crystallinity index increased from 40.5 to 52.3%, indicating the higher exposure of cellulose. With 10% (w/v solid loadings of pretreated RS, simultaneous saccharification and fermentation yielded a final ethanol concentration of 24.6 g/L, corresponding to 98% of maximum theoretical yield. Taken together, aqueous ammonia pretreatment is an effective method to generate highly digestible pretreated RS for bioethanol production and demonstrates potential application in biorefinery industry.

  6. Characterization of materials formed by rice husk for construction

    Science.gov (United States)

    Portillo-Rodríguez, A. M.

    2013-11-01

    This review article delves into the use of agro-industrial wastes, which in construction field provides alternatives for environmental problems with the use of them. This fact enables development and lower costs for new options in the brick, cluster, mortar and concrete industry, what represents benefits for environment, housing and generally everything related to construction, looking for sustainability. For that reason a literature review is made to support the theme focusing on the use of rice husk in its natural, ground or ash state for manufacturing elements with clay masonry, precast and optimization of concrete and mortars. The technique used is based on scientific articles and researches found in reliable databases that were analyzed and integrated into a synthesized structure, which summarized the objectives, analysis processes, the physical and mechanical properties and finally the results. The conclusions are focused on potentiality of elements production in the construction development based on the high effectiveness like thermal insulation, low density and various benefits offered by high silica content pozzolanic properties, etc.

  7. [Safety of rice grains and mycotoxins - a historical review of yellow rice mycotoxicoses].

    Science.gov (United States)

    Udagawa, Shun-ichi; Tatsuno, Takashi

    2004-01-01

    Aflatoxins, the most powerful mycotoxins, were brought to the attention fo the people in the early 1960s with the outbreak of the turkey "X" disease in England. However, the history of mycotoxin research in Japan began 100 years ago. In 1891, Sakaki demonstrated that moldy, unpolished rice was fatal to experimental animals, with symptoms indicating paralysis of the central nervous system (Shoshin-kakke). In 1920, Prof. I. Miyake and Dr. Takada first reported that Penicillium commune, which was known as a causal agent of "Mossy diseased rice" was found to be toxic to experimental animals by feeding the moldy rice to rabbits and rats.With such a historical background, taking the idea of "rice, fungus and toxin" as a working hypothesis, Miyake and his co-workers discovered the first sample of yellow rice grains from Taiwanese and domestic rice, from which was isolated a species of Penicillium and later identified it with P. citreonigrum (=P. toxicarium). The fungus produced a highly toxic metabolite, citreoviridin. Unfortunately because this study was published during wartime, it failed to alert the world to the potential or actual dangers of the toxicity of common molds. After World War II, Japanese people suffered for some years from a shortage in domestic rice production and depended on foreign countries to supply rice, which led to the toxicological screening on fungal isolates from polluted rice grains by Dr. Tsunoda and his co-workers. AMong the isolates from imported rice, there were two species of Penicillium which were particularly associated with high toxicity; P. islandicum responsible for brownish discolored rice, and P. citrinum responsible for yellowish rice. P. islandicum produces two hepatotoxic metabolites: luteoskyrin and cyclochlorotine, while a nephrotoxic of P. citrinum is citrinin. These toxicological characters, including the induction of cancer and chemical structures, were studied by Profs. uraguchi, Saito, Shibata, Tatsuno and their co

  8. Evaluation of Heavy Metals Contamination from Environment to Food Matrix by TXRF: The Case of Rice and Rice Husk

    Directory of Open Access Journals (Sweden)

    Fabjola Bilo

    2015-01-01

    Full Text Available This paper is devoted to the chemical analysis of contaminated soils of India and the rice grown in the same area. Total reflection X-ray fluorescence spectroscopy is a well-established technique for elemental chemical analysis of environmental samples, and it can be a useful tool to assess food safety. Metals uptake in rice crop grown in soils from different areas was studied. In this work soil, rice husk and rice samples were analyzed after complete solubilization of samples by microwave acid digestion. Heavy metals concentration detected in rice samples decreases in the following order: Mn > Zn > Cu > Ni > Pb > Cr. The metal content in rice husk was higher than in rice. This study suggests, for the first time, a possible role of heavy metals filter played by rice husk. The knowledge of metals sequestration capability of rice husk may promote some new management practices for rice cultivation to preserve it from pollution.

  9. Rice Husk Filled Polymer Composites

    Directory of Open Access Journals (Sweden)

    Reza Arjmandi

    2015-01-01

    Full Text Available Natural fibers from agricultural wastes are finding their importance in the polymer industry due to the many advantages such as their light weight, low cost and being environmentally friendly. Rice husk (RH is a natural sheath that forms around rice grains during their growth. As a type of natural fiber obtained from agroindustrial waste, RH can be used as filler in composites materials in various polymer matrices. This review paper is aimed at highlighting previous works of RH filled polymer composites to provide information for applications and further research in this area. Based on the information gathered, application of RH filled composites as alternative materials in building and construction is highly plausible with both light weight and low cost being their main driving forces. However, further investigations on physical and chemical treatment to further improve the interfacial adhesion with polymeric matrix are needed as fiber-polymer interaction is crucial in determining the final composite properties. Better understanding on how the used polymer blends as the matrix and secondary fillers may affect the properties would provide interesting areas to be explored.

  10. Use of nitrogen from fertilizer and cover crops by upland rice in an Oxisol under no-tillage in the Cerrado

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Edson Cabral da; Muraoka, Takashi; Bendassolli, Jose Alberto, E-mail: edsoncabralsilva@gmail.com, E-mail: muraoka@cena.usp.br, E-mail: jab@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil); Franzini, Vinicius Ide, E-mail: vinicius.franzini@embrapa.br [Embrapa Amazonia Oriental, Belem, PA (Brazil); Sakadevan, Karuppan, E-mail: K.Sakadevan@iaea.org [Joint FAO/IAEA, Division of Nuclear Techniques in Food and Agriculture, Soil and Water Management and Crop Nutrition Subprogram, Vienna International Centre, Vienna (Austria); Buzetti, Salatier; Arf, Orivaldo, E-mail: sbuzetti@agr.feis.unesp.br, E-mail: arf@agr.feis.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Ilha Solteira, SP (Brazil). Faculdade de Engenharia; Soares, Frederico Antonio Loureiro, E-mail: fredalsoares@hotmail.com [Instituto Federal Goiano, Rio Verde, GO (Brazil)

    2016-06-15

    The objective of this work was to evaluate the effects of cover crops on the yield of upland rice (Oryza sativa) grown under no-tillage system, in the presence and absence of N fertilizer, as well as to quantify, in the field, the use efficiency of N from urea and cover crops by upland rice, through the {sup 15}N isotope dilution technique. The field experiment was carried out in the municipality of Selviria, in the state of Mato Grosso do Sul, Brazil, in an Oxisol (Rhodic Hapludox) in the Cerrado (Brazilian savanna) region. The experimental design was a randomized complete block with 15 treatments and four replicates, in a 5 x 3 factorial arrangement. The treatments were four cover crops (Crotalaria juncea, Cajanus cajan, Mucuna pruriens, and Pennisetum glaucum) + spontaneous vegetation (fallow in off-season), combined with three forms of N fertilization: control treatment, without N fertilizer application; 20 kg ha{sup -1} N at sowing; and 20 kg ha{sup -1} N at sowing plus 60 kg ha{sup -1} N as topdressing. Rice is not affected by N fertilizer application as topdressing, when legume cover crops are used. The use of legume cover crops provides higher grain yield and use of fertilizer-N by rice than that of millet or fallow. Legume cover crops promote an effect equivalent to that of the application of 60 kg ha{sup -1} N as urea on rice yield. (author)

  11. Response of aerobic rice to Piriformospora indica.

    Science.gov (United States)

    Das, Joy; Ramesh, K V; Maithri, U; Mutangana, D; Suresh, C K

    2014-03-01

    Rice cultivation under aerobic condition not only saves water but also opens up a splendid scope for effective application of beneficial root symbionts in rice crop unlike conventional puddled rice cultivation where water logged condition acts as constraint for easy proliferation of various beneficial soil microorganisms like arbuscular mycorrhizal (AM) fungi. Keeping these in view, an in silico investigation were carried out to explore the interaction of hydrogen phosphate with phosphate transporter protein (PTP) from P. indica. This was followed by greenhouse investigation to study the response of aerobic rice to Glomusfasciculatum, a conventional P biofertilizer and P. indica, an alternative to AM fungi. Computational studies using ClustalW tool revealed several conserved motifs between the phosphate transporters from Piriformospora indica and 8 other Glomus species. The 3D model of PTP from P. indica resembling "Mayan temple" was successfully docked onto hydrogen phosphate, indicating the affinity of this protein for inorganic phosphorus. Greenhouse studies revealed inoculation of aerobic rice either with P. indica, G. fasciculatum or both significantly enhanced the plant growth, biomass and yield with higher NPK, chlorophyll and sugar compared to uninoculated ones, P. indica inoculated plants being superior. A significantly enhanced activity of acid phosphatase and alkaline phosphatase were noticed in the rhizosphere soil of rice plants inoculated either with P. indica, G. fasciculatum or both, contributing to higher P uptake. Further, inoculation of aerobic rice plants with P. indica proved to be a better choice as a potential biofertilizer over mycorrhiza.

  12. Silica Synthesis by Sponges: Unanticipated Molecular Mechanism

    Science.gov (United States)

    Morse, D. E.; Weaver, J. C.

    2001-12-01

    Oceanic diatoms, sponges and other organisms synthesize gigatons per year of silica from silicic acid, ultimately obtained from the weathering of rock. This biogenic silica exhibits a remarkable diversity of structures, many of which reveal a precision of nanoarchitectural control that exceeds the capabilities of human engineering. In contrast to the conditions of anthropogenic and industrial manufacture, the biological synthesis of silica occurs under mild physiological conditions of low temperatures and pressures and near-neutral pH. In addition to the differentiation between biological and abiotic processes governing silica formation, the biomolecular mechanisms controlling synthesis of these materials may offer insights for the development of new, environmentally benign routes for synthesis of nanostructurally controlled silicas and high-performance polysiloxane composites. We found that the needle-like silica spicules made by the marine sponge, Tethya aurantia, each contain an occluded axial filament of protein composed predominantly of repeating assemblies of three similar subunits we named "silicateins." To our surprise, analysis of the purified protein subunits and the cloned silicatein DNAs revealed that the silicateins are highly homologous to a family of hydrolytic enzymes. As predicted from this finding, we discovered that the silicatein filaments are more than simple, passive templates; they actively catalyze and spatially direct polycondensation to form silica, (as well as the phenyl- and methyl-silsesquioxane) from the corresponding silicon alkoxides at neutral pH and low temperature. Catalytic activity also is exhibited by the silicatein subunits obtained by disaggregation of the protein filaments and those produced from recombinant DNA templates cloned in bacteria. This catalytic activity accelerates the rate-limiting hydrolysis of the silicon alkoxide precursors. Genetic engineering, used to produce variants of the silicatein molecule with

  13. Generation of crystalline silica from sugarcane burning.

    Science.gov (United States)

    Le Blond, Jennifer S; Horwell, Claire J; Williamson, Ben J; Oppenheimer, Clive

    2010-07-08

    Sugarcane leaves contain amorphous silica, which may crystallise to form crystalline silica polymorphs (cristobalite or quartz), during commercial sugarcane harvesting where sugarcane plants are burned. Respirable airborne particulate containing these phases may present an occupational health hazard. Following from an earlier pilot study (J. S. Le Blond, B. J. Williamson, C. J. Horwell, A. K. Monro, C. A. Kirk and C. Oppenheimer, Atmos. Environ., 2008, 42, 5558-5565) in which experimental burning of sugarcane leaves yielded crystalline silica, here we report on actual conditions during sugarcane burning on commercial estates, investigate the physico-chemical properties of the cultivated leaves and ash products, and quantify the presence of crystalline silica. Commercially grown raw sugarcane leaf was found to contain up to 1.8 wt% silica, mostly in the form of amorphous silica bodies (with trace impurities e.g., Al, Na, Mg), with only a small amount of quartz. Thermal images taken during several pre-harvest burns recorded temperatures up to 1056 degrees C, which is sufficient for metastable cristobalite formation. No crystalline silica was detected in airborne particulate from pre-harvest burning, collected using a cascade impactor. The sugarcane trash ash formed after pre-harvest burning contained between 10 and 25 wt% SiO(2), mostly in an amorphous form, but with up to 3.5 wt% quartz. Both quartz and cristobalite were identified in the sugarcane bagasse ash (5-15 wt% and 1-3 wt%, respectively) formed in the processing factory. Electron microprobe analysis showed trace impurities of Mg, Al and Fe in the silica particles in the ash. The absence of crystalline silica in the airborne emissions and lack of cristobalite in trash ash suggest that high temperatures during pre-harvest burning were not sustained long enough for cristobalite to form, which is supported by the presence of low temperature sylvite and calcite in the residual ash. The occurrence of quartz and

  14. Silica-Rich Soil Found by Spirit

    Science.gov (United States)

    2007-01-01

    NASA's Mars Exploration Rover Spirit has found a patch of bright-toned soil so rich in silica that scientists propose water must have been involved in concentrating it. The silica-rich patch, informally named 'Gertrude Weise' after a player in the All-American Girls Professional Baseball League, was exposed when Spirit drove over it during the 1,150th Martian day, or sol, of Spirit's Mars surface mission (March 29, 2007). One of Spirit's six wheels no longer rotates, so it leaves a deep track as it drags through soil. Most patches of disturbed, bright soil that Spirit had investigated previously are rich in sulfur, but this one has very little sulfur and is about 90 percent silica. This image is a approximately true-color composite of three images taken through different filters by Spirit's panoramic camera on Sol 1,187 (May 6). The track of disturbed soil is roughly 20 centimeters (8 inches) wide. Spirit's miniature thermal emission spectrometer, which can assess a target's mineral composition from a distance, examined the Gertrude Weise patch on Sol 1,172 (April 20). The indications it found for silica in the overturned soil prompted a decision to drive Spirit close enough to touch the soil with the alpha particle X-ray spectrometer, a chemical analyzer at the end of Spirit's robotic arm. The alpha particle X-ray spectrometer collected data about this target on sols 1,189 and 1,190 (May 8 and May 9) and produced the finding of approximately 90 percent silica. Silica is silicon dioxide. On Earth, it commonly occurs as the crystalline mineral quartz and is the main ingredient in window glass. The Martian silica at Gertrude Weise is non-crystalline, with no detectable quartz. In most cases, water is required to produce such a concentrated deposit of silica, according to members of the rover science team. One possible origin for the silica could have been interaction of soil with acidic steam produced by volcanic activity. Another could have been from water in a hot

  15. Silica-Rich Soil in Gusev Crater

    Science.gov (United States)

    2007-01-01

    NASA's Mars Exploration Rover Spirit has found a patch of bright-toned soil so rich in silica that scientists propose water must have been involved in concentrating it. The silica-rich patch, informally named 'Gertrude Weise' after a player in the All-American Girls Professional Baseball League, was exposed when Spirit drove over it during the 1,150th Martian day, or sol, of Spirit's Mars surface mission (March 29, 2007). One of Spirit's six wheels no longer rotates, so it leaves a deep track as it drags through soil. Most patches of disturbed, bright soil that Spirit had investigated previously are rich in sulfur, but this one has very little sulfur and is about 90 percent silica. Spirit's panoramic camera imaged the bright patch through various filters on Sol 1,158 (April 6). This approximately true-color image combines images taken through three different filters. The track of disturbed soil is roughly 20 centimeters (8 inches) wide. Spirit's miniature thermal emission spectrometer, which can assess a target's mineral composition from a distance, examined the Gertrude Weise patch on Sol 1,172 (April 20). The indications it found for silica in the overturned soil prompted a decision to drive Spirit close enough to touch the soil with the alpha particle X-ray spectrometer, a chemical analyzer at the end of Spirit's robotic arm. The alpha particle X-ray spectrometer collected data about this target on sols 1,189 and 1,190 (May 8 and May 9) and produced the finding of approximately 90 percent silica. Silica is silicon dioxide. On Earth, it commonly occurs as the crystalline mineral quartz and is the main ingredient in window glass. The Martian silica at Gertrude Weise is non-crystalline, with no detectable quartz. In most cases, water is required to produce such a concentrated deposit of silica, according to members of the rover science team. One possible origin for the silica could have been interaction of soil with acidic steam produced by volcanic activity

  16. A convenient method for rapid determination of proteins in rices and rice products

    OpenAIRE

    光永, 俊郎; 安藤, ひとみ

    1990-01-01

    [Author abstract]In the biuret determination of protein in rices and rice products, starch and lipids extractable with an alkaline solution such as biuret reagent were found to interfere with the biuret method. Comparative evaluation of their effects revealed that starch, a major component of rice, has the most significant effect on the biuret method. In the presence of starch, the correlation between Kjeldahl protein and the optical density of biuret was poor. It was found that several perha...

  17. Chemical Looping Combustion of Rice Husk

    OpenAIRE

    Rashmeet Singh Monga; Ganesh R. Kale

    2015-01-01

    A thermodynamic investigation of direct chemical looping combustion (CLC) of rice husk is presented in this paper. Both steam and CO2 are used for gasification within the temperature range of 500–1200˚C and different amounts of oxygen carriers. Chemical equilibrium model was considered for the CLC fuel reactor. The trends in product compositions of the fuel reactor, were determined. Rice husk gasification using 3 moles H2O and 0 moles CO2 per mole carbon (in rice husk) at 1 bar pr...

  18. Feeding behavior of rice bug Leptocorisa chinensis (Dallas) (Heteroptera: Alydidae) nymphs on rice panicles and rice plant extract

    National Research Council Canada - National Science Library

    Ishizaki, Mami; Yasuda, Tetsuya; Watanabe, Tomonari

    2007-01-01

    .... The nymphs showed typical behavioral phases towards the rice panicles: antennation, extension of the rostrum, repeated dabbing with the labium, rostrum placing on the plant surface, stylet penetration and continuous sucking...

  19. Impact of milling and water-to-rice ratio on cooked rice and wastewater properties.

    Science.gov (United States)

    Altheide, M C; Morawicki, R O; Hager, T J

    2012-06-01

    Due to the environmental concerns and expense associated with the disposal of wastewater after industrial cooking of rice, the purpose of this study was to evaluate the extent of leaching, water uptake and volumetric expansion of rice during cooking at various milling durations and water-to-rice ratios. Two cultivars of Arkansas rice, a long grain (Francis) and a medium grain (Jupiter), were milled for 10, 20, and 30 s with a laboratory mill. Samples were cooked in aluminum foil covered beakers at water-to-rice ratios of 10:1, 15:1, and 20:1. After 20 min, rice was weighed for water uptake and measured for volumetric expansion using hexane displacement. The excess cooking water was evaluated for total solids, amylose, and protein to determine the extent of leaching. Water uptake and volumetric expansion significantly increased with milling duration in both cultivars. Leached solids increased as the water-to-rice ratio increased in Francis and increased with milling duration in Jupiter; however, the amylose content of leached solids was unaffected by the water-to-rice ratio in both cultivars. Thus, shorter milling durations may limit the extent of leaching during cooking, as observed with Jupiter, while a lower water-to-rice ratio may reduce wastewater contamination for cultivars similar to Francis.

  20. Characterization of Volatile Flavor Compounds in Chinese Rice Wine Fermented from Enzymatic Extruded Rice.

    Science.gov (United States)

    Xu, Enbo; Long, Jie; Wu, Zhengzong; Li, Hongyan; Wang, Fang; Xu, Xueming; Jin, Zhengyu; Jiao, Aiquan

    2015-07-01

    Enzymatic extrusion, instead of traditional steam cooking, to treat rice is an efficient and alternative pretreatment for Chinese rice wine fermentation. In order to determine the formation of volatiles in enzymatic extrusion-processed rice wine (EE), and to confirm its characteristic flavor compounds, headspace solid-phase micro-extraction followed by GC-MS was used. A total of 66 volatile compounds were identified in EE. During fermentation, most volatiles generated from enzymatic extruded rice had the similar trends with those from steam-cooked rice, but the differences in the concentration of volatiles indicated a changed balance of flavors release caused by enzymatic extrusion. Besides, the concentrations and sorts of volatiles in EEs fermented from different rice particle sizes, were not dramatically different. By principal component analysis, EE could be distinctly separated from other traditional Chinese rice wines according to its characteristic volatiles, namely, 2-heptanol, 1-octen-3-ol, ethyl 4-hydroxybenzoate, methylpentyl 2-propenoate, γ-hexalactone, and 4-vinylguaiacol. Enzymatic extrusion liquefaction has been a popular thermal treatment for cereals, and gradually being applied in fermentation and liquor-making industry all over the world. The characterization of volatile flavor compounds in Chinese rice wine processed by enzymatic extrusion liquefaction pretreatment, might be made use not only for a better understanding of this new-type rice wine, but for the further utilization of enzymatic extrusion in other wine or alcohol production as well. © 2015 Institute of Food Technologists®

  1. Surfactant removal and silica condensation during the photochemical calcination of thin film silica mesophases.

    Science.gov (United States)

    Dattelbaum, Andrew M; Amweg, Meri L; Ruiz, Julia D; Ecke, Laurel E; Shreve, Andrew P; Parikh, Atul N

    2005-08-04

    The evolution of photochemical surfactant removal and silica condensation from organically templated thin film silica nanocomposites with mesoscopic ordering has been probed using a combined application of Fourier transform infrared (FT-IR) spectroscopy and single wavelength ellipsometry. Thin films of silica nanocomposites were prepared by a previously reported evaporation-induced self-assembly process. Specifically, oxidized silicon and gold substrates were withdrawn at 25 mm/min from a subcritical micelle concentration solution containing an ethylene oxide surfactant as a structure-directing agent and tetraethyl orthosilicate as a silica precursor. Real-time grazing incidence difference FT-IR spectra of the nanocomposite films on gold taken during exposure to short-wavelength ultraviolet light (184-257 nm) show that surfactant removal and silica condensation occur gradually and concomitantly. Surfactant removal and silica reconstructions were found to be nearly complete after 90 min of exposure. Further, a transient feature was observed in the FT-IR spectra around 1713 cm(-1) during the UV exposure process and was assigned to a carbonyl (C=O) stretching mode absorption, reflecting the transient formation of a partially oxidized surfactant intermediate. From these data we propose a stepwise model for surfactant removal from the nanocomposite films. Ellipsometrically determined index of refraction values collected as a function of UV exposure are also shown to support such a stepwise mechanism of surfactant removal from the ordered nanocomposite silica thin film mesophases studied here.

  2. Surface treatment of silica nanoparticles for stable and charge-controlled colloidal silica.

    Science.gov (United States)

    Kim, Kyoung-Min; Kim, Hye Min; Lee, Won-Jae; Lee, Chang-Woo; Kim, Tae-il; Lee, Jong-Kwon; Jeong, Jayoung; Paek, Seung-Min; Oh, Jae-Min

    2014-01-01

    An attempt was made to control the surface charge of colloidal silica nanoparticles with 20 nm and 100 nm diameters. Untreated silica nanoparticles were determined to be highly negatively charged and have stable hydrodynamic sizes in a wide pH range. To change the surface to a positively charged form, various coating agents, such as amine containing molecules, multivalent metal cation, or amino acids, were used to treat the colloidal silica nanoparticles. Molecules with chelating amine sites were determined to have high affinity with the silica surface to make agglomerations or gel-like networks. Amino acid coatings resulted in relatively stable silica colloids with a modified surface charge. Three amino acid moiety coatings (L-serine, L-histidine, and L-arginine) exhibited surface charge modifying efficacy of L-histidine > L-arginine > L-serine and hydrodynamic size preservation efficacy of L-serine > L-arginine > L-histidine. The time dependent change in L-arginine coated colloidal silica was investigated by measuring the pattern of the backscattered light in a Turbiscan™. The results indicated that both the 20 nm and 100 nm L-arginine coated silica samples were fairly stable in terms of colloidal homogeneity, showing only slight coalescence and sedimentation.

  3. Interfacial interaction between the epoxidized natural rubber and silica in natural rubber/silica composites

    Science.gov (United States)

    Xu, Tiwen; Jia, Zhixin; Luo, Yuanfang; Jia, Demin; Peng, Zheng

    2015-02-01

    The epoxidized natural rubber (ENR) as an interfacial modifier was used to improve the mechanical and dynamical mechanical properties of NR/silica composites. In order to reveal the interaction mechanism between ENR and silica, the ENR/Silica model compound was prepared by using an open mill and the interfacial interaction of ENR with silica was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and stress-strain testing. The results indicated that the ring-opening reaction occurs between the epoxy groups of ENR chains and Si-OH groups on the silica surfaces and the covalent bonds are formed between two phases, which can improve the dispersion of silica in the rubber matrix and enhance the interfacial combination between rubber and silica. The ring-opening reaction occurs not only in vulcanization process but also in mixing process, meanwhile, the latter seems to be more important due to the simultaneous effects of mechanical force and temperature.

  4. Functional Films from Silica/Polymer Nanoparticles

    Directory of Open Access Journals (Sweden)

    Tânia Ribeiro

    2014-05-01

    Full Text Available High performance functional coatings, based on hybrid organic/inorganic materials, are being developed to combine the polymer flexibility and ease of processing with the mechanical properties and versatility of inorganic materials. By incorporating silica nanoparticles (SiNPs in the polymeric matrices, it is possible to obtain hybrid polymer films with increased tensile strength and impact resistance, without decreasing the flexural properties of the polymer matrix. The SiNPs can further be used as carriers to impart other functionalities (optical, etc. to the hybrid films. By using polymer-coated SiNPs, it is possible to reduce particle aggregation in the films and, thus, achieve more homogeneous distributions of the inorganic components and, therefore, better properties. On the other hand, by coating polymer particles with silica, one can create hierarchically structured materials, for example to obtain superhydrophobic coatings. In this review, we will cover the latest developments in films prepared from hybrid polymer/silica functional systems.

  5. Silica exposure and silicosis in Alberta, Canada.

    Science.gov (United States)

    Lappi, Vernon G; Radnoff, Diane L; Karpluk, Phil F

    2014-10-01

    To study potential exposures to crystalline silica and the number of work-related cases of silicosis occurring in Alberta. Exposure data comprising 343 occupational samples were collected at 40 worksites across 13 industries. To assess silicosis reporting, cases reported to the Alberta government, claims accepted by the Workers' Compensation Board for work-related silicosis, and billings to Alberta Health for medical services with a diagnostic code for silicosis during a similar time period were compared. Workers potentially over-exposed to airborne respirable crystalline silica were identified at most of the worksites evaluated. There were large discrepancies in the number of silicosis cases found. Many Alberta workers may be over-exposed to airborne respirable crystalline silica, and the incidence of work-related silicosis in Alberta may not be adequately represented by the official statistics.

  6. Vanadia-silica aerogels from vanadylacetylacetonate

    Energy Technology Data Exchange (ETDEWEB)

    Klett, U.; Fricke, J. [Bavarian Center for Applied Energy Research (ZAE)/Physikalisches Institut der Universitaet Wuerzburg, Am Hubland, D-97074 Wuerzburg (Germany)

    1998-04-15

    For the preparation of vanadium pentoxide doped silica gels, vanadium(V) oxide trialkoxides are the precursors of choice as they possess already the desired oxidation number. In vanadylacetylacetonate, the oxidation number of vanadium is only +4 instead of +5. However, vanadylacetylacetonate is less reactive with water and thus easier to handle, less toxic and cheaper than vanadium(V) oxide triisopropoxide. Gels were prepared using vanadylacetylacetonate, tetramethoxysilane, methanol and water containing HCl or NH{sub 3} as catalyst. After supercritical drying with respect to CO{sub 2} and heat treatment in air, vanadia doped silica aerogels show the same colour change upon adsorption of water molecules as vanadium(V) oxide triisopropoxide doped silica xerogels. Structural properties were investigated by N{sub 2}-absorption and SAXS measurements

  7. Fused silica windows for solar receiver applications

    Science.gov (United States)

    Hertel, Johannes; Uhlig, Ralf; Söhn, Matthias; Schenk, Christian; Helsch, Gundula; Bornhöft, Hansjörg

    2016-05-01

    A comprehensive study of optical and mechanical properties of quartz glass (fused silica) with regard to application in high temperature solar receivers is presented. The dependence of rupture strength on different surface conditions as well as high temperature is analyzed, focussing particularly on damage by devitrification and sandblasting. The influence of typical types of contamination in combination with thermal cycling on the optical properties of fused silica is determined. Cleaning methods are compared regarding effectiveness on contamination-induced degradation for samples with and without antireflective coating. The FEM-aided design of different types of receiver windows and their support structure is presented. A large-scale production process has been developed for producing fused silica dome shaped windows (pressurized window) up to a diameter of 816 mm. Prototypes were successfully pressure-tested in a test bench and certified according to the European Pressure Vessel Directive.

  8. The effect of silica toward polymer membrane for water separation process

    Science.gov (United States)

    Jamalludin, Mohd Riduan; Rosli, M. U.; Ishak, Muhammad Ikman; Khor, C. Y.; Shahrin, Suhaimi; Ismail, Ras Izzati; Lailina N., M.; Leng Y., L.; Jahidi, H.

    2017-09-01

    The aim of this present work was to investigate the effect of different percentage rice husk silica (RHS) particles composition towards polymer mixed matrix membrane microstructure and performance in water separation process. The polymer membranes were prepared by a phase inversion method using polysulfone (PSf), N-methyl-2-pyrrolidone (NMP) as solvent, distilled water as non-solvent and fixed RHS at 400°C as an additive. The microstructures of PSf/PEG/RHS sample were characterized by performing scanning electron microscope (SEM). The performance was measured by using pure water flux and humic acid for the rejection test. The analyzed result of SEM analysis revealed that the addition of RHS obviously improved the microstructure of the membrane especially at the top and sub layer at the range of 1 until 3 wt. %. This was proven by the pure water flux (PWF) value measured from 114.47 LMH to 154.04 LMH and rejection from value 83% to 96% at this specified range substantially higher than the mixed matrix membrane with synthetic silica. In fact, the presence of RHS particles not only improved the properties and performance of membrane but also possess biodegradable properties which can minimize the pollution and provide a membrane green technology system.

  9. Glass fiber and silica reinforced rigid polyurethane foams

    National Research Council Canada - National Science Library

    M W Kim; S H Kwon; H Park; B K Kim

    2017-01-01

    Ternary composites of rigid polyurethane foam (RPUF)/glass fiber/silica as well as RPUF/glass fiber have been fabricated from glass fiber, silica, polymeric 4,4'-di-phenylmethane diisocyanate (PMDI...

  10. Synthesis of very small diameter silica nanofibers using sound waves.

    Science.gov (United States)

    Datskos, Panos; Chen, Jihua; Sharma, Jaswinder

    2014-07-14

    Silica nanofibers of an average diameter ≈30 nm and length ≈100 μm have been synthesized using an unprecedented strategy: sound waves. A new phenomenon, spinning off the nanofibers at silica rod tips, is also observed.

  11. silica nanoparticles as a highly efficient catalyst for the one

    African Journals Online (AJOL)

    )-2-aryl acetamide derivatives via a three-component reaction of an isocyanide, dibenzylamine and a phthalaldehyde derivative in the presence of silica nanoparticles (silica NPs, ca. 42 nm) as a catalyst under solvent free conditions at room.

  12. Adsorption of mercury ions by mercapto-functionalized amorphous silica

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Quintanilla, Damian; Hierro, Isabel del; Fajardo, Mariano; Sierra, Isabel [Universidad Rey Juan Carlos, Departamento de Tecnologia Quimica y Ambiental, E.S.C.E.T, Mostoles, Madrid (Spain); Carrillo-Hermosilla, Fernando [Universidad de Castilla-La Mancha, Departamento de Quimica Inorganica, Organica y Bioquimica, Facultad de Quimicas, Ciudad Real (Spain)

    2006-02-01

    Amorphous silicas have been functionalized by two different methods. In the heterogeneous route the silylating agent, 3-chloropropyltriethoxysilane, was initially immobilized onto the silica surface to give the chlorinated silica Cl-Sil. In a second reaction, multifunctionalized N,S donor compounds were incorporated to obtain the functionalized silicas, which are denoted as L-Sil-Het (where L=mercaptothiazoline, mercaptopyridine or mercaptobenzothiazole). In the homogeneous route, the functionalization was achieved through a one-step reaction between the silica and an organic ligand containing the chelating functions; this gave the modified silicas denoted as L-Sil-Hom. The functionalized silicas were characterized by elemental analysis, IR spectroscopy and thermogravimetry. These materials were employed as adsorbents for mercury cations from aqueous and acetone solutions at room temperature. The results indicate that, in all cases, mercury adsorption was higher in the modified silicas prepared by the homogeneous method. (orig.)

  13. Respiratory health effects of exposure to crystalline silica epidemiology.

    CSIR Research Space (South Africa)

    Hnzido, E

    1999-01-01

    Full Text Available The present report describes two additional studies of exposure-response relationship between respiratory disease and silica dust in gold mines. Section 3 describes a study of pulmonary tuberculosis in relation to silica dust, and section 4...

  14. Infrared Reflectance Spectroscopy of Porous Silicas

    Science.gov (United States)

    Guiton, Theresa Anne

    Fourier transform infrared (FTIR) specular reflectance spectroscopy was used to examine the fundamental phonon behavior of a series of porous silicas including porous Vycor, xerogels, aerogels, and colloidal solids. The spectra were deconvoluted using Kramers-Kronig analysis techniques, and the corresponding optical constants were determined via the Fresnel equations. The resulting spectra represent the first compilation of such data for low density silicas. The porous silicas revealed unique resonance modes for the imaginary dielectric function and energy loss function. A key distinction amongst the spectra was the change in the band shape of the antisymmetric Si-O-Si stretching modes. For instance, as the porosity level of the particulate systems increased, the peak maxima of the imaginary dielectric functions shifted to higher frequencies while the peak maxima of the associated energy loss function shifted to lower frequencies. In essence, with increasing porosity, the peak maxima of the imaginary dielectric functions and the energy loss functions were converging towards frequencies intermediate to the transverse optical and longitudinal optical modes of fused silica. A similar trend was not observed for the semi-continuous silica matrices. Maxwell Garnett effective medium modeling verified that these modes were a function of the porous microstructure and can be attributed to surface phonon modes. The effect of surface phonon modes was also evident in the absorption coefficient data. However, contrary to the traditional view that changes in the absorption spectra of porous silicas are strictly due to molecular structure, this study has demonstrated that variations can be attributed--both qualitatively and quantitatively--to electrostatic screening effects of finite particles.

  15. Vacuum arc on the polycrystalline silica cathode

    Directory of Open Access Journals (Sweden)

    D. V. Duhopel'nikov

    2014-01-01

    Full Text Available Thin films of silica and its compounds are used in modern technology to produce Li-ion batteries, wear-resistant and protective coatings, thin-films insulators, etc. This coating is produced with CVD methods, with magnetron sputtering systems or with electron-beam evaporation. The vacuum arc evaporation method, presently, is not used.The paper demonstrates a possibility for a long-term operation of vacuum arc evaporator with polycrystalline silica-aluminum alloy (90% of silica cathode and with magnetic system to create a variable form of arch-like magnetic field on the cathode surface. It was shown that archlike configuration of magnetic field provides a stable discharge and uniform cathode spots moving with the velocities up to 5 m/s with magnetic fields induction about 10 mT. Thus, there is no local melting of the cathode, and this provides its long-term work without chips, cracks and destruction. Cathodes spots move over the cathode surface leaving t big craters with melted edges on its surface. The craters size was 150-450μm. The cathode spot movement character and the craters on the cathode surface were like the spots movement, when working on the copper or aluminum cathodes. With the magnetic field induction less than 1 mT, the cathode spots movement was the same as that of on the silica mono-crystal without magnetic field. Thus, the discharge volt-ampere characteristics for different values of magnetic fields were obtained. Voltampere characteristics were increasing and were shifted to the higher voltage with increasing magnetic field. The voltage was 18.7-26.5 V for the arc current 30-140 A.So, it was confirmed that vacuum arc evaporation method could be used for effective evaporation of silica and silica-based alloys and for thin films deposition of this materials.

  16. Silica-scaled chrysophytes of Lake Baikal

    Directory of Open Access Journals (Sweden)

    A. Yu. Bessudova

    2017-12-01

    Full Text Available The list of silica-scaled chrysophytes of Lake Baikal has been enlarged using electron microscopy. It has been supplemented with 12 species and 2 forms. Spiniferomonas takahashii has been observed for the first time in the water bodies of Russia. According to our data, the list of silica-scaled chrysophytes of Lake Baikal includes 25 species and intra-species taxa: Chrysosphaerella – 3, Paraphysomonas – 2, Clathromonas – 1, Spiniferomonas – 7, Mallomonas – 8 and Synura – 4. We have also analyzed their seasonal dynamics and observed algal species that are dominant in spring, summer and autumn.

  17. Olefin metathesis over UV-irradiated silica

    Science.gov (United States)

    Tanaka, Tsunehiro; Matsuo, Shigehiro; Maeda, Takashi; Yoshida, Hisao; Funabiki, Takuzo; Yoshida, Satohiro

    1997-11-01

    Photoirradiated silica evacuated at temperatures higher than 800 K was found to be active for olefin metathesis reactions. The analysis of products shows that the metalacyclobutane intermediate is likely. The instantaneous response of the reaction to the irradiation and the activity change with various UV filter showed that the reaction is induced by UV-excitation of silica. The correlation between the evacuation temperature and the activity showed that the surface free from water molecules plays a role in the reaction and the removal of isolated OH groups strongly relates to the generation of active sites.

  18. Ordered mesoporous silica materials with complicated structures

    KAUST Repository

    Han, Yu

    2012-05-01

    Periodically ordered mesoporous silicas constitute one of the most important branches of porous materials that are extensively employed in various chemical engineering applications including adsorption, separation and catalysis. This short review gives an introduction to recently developed mesoporous silicas with emphasis on their complicated structures and synthesis mechanisms. In addition, two powerful techniques for solving complex mesoporous structures, electron crystallography and electron tomography, are compared to elucidate their respective strength and limitations. Some critical issues and challenges regarding the development of novel mesoporous structures as well as their applications are also discussed. © 2011 Elsevier Ltd.

  19. ESR of vitreous silica containing hydroxyl

    Energy Technology Data Exchange (ETDEWEB)

    Shendrik, A.V. (Latvijskij Gosudarstvennyj Univ., Riga (USSR))

    1981-09-16

    H(II) centers in vitreous silica containing Al or Ge were investigated by ESR measurements at 77 K. Vitreous silica samples were melted in an electric resistance furnace in hydrogen atmosphere or by SiCl/sub 4/ vapor oxidation in the flame of an oxyhydrogen burner and irradiated with /sup 60/Co-gamma doses of 5 x 10/sup 7/ rad at 300 K. It was found that hydrogen atoms are localized at the H(II) center near the non-bridging oxygen of the germanium-oxygen structural unit.

  20. Measurement of muonium emission from silica aerogel

    CERN Document Server

    Bakule, P; Contreras, D; Esashi, M; Fujiwara, Y; Fukao, Y; Hirota, S; Iinuma, H; Ishida, K; Iwasaki, M; Kakurai, T; Kanda, S; Kawai, H; Kawamura, N; Marshall, G M; Masuda, H; Matsuda, Y; Mibe, T; Miyake, Y; Okada, S; Olchanski, K; Olin, A; Onishi, H; Saito, N; Shimomura, K; Strasser, P; Tabata, M; Tomono, D; Ueno, K; Yokoyama, K; Yoshida, S

    2013-01-01

    Emission of muonium ($\\mu^{+}e^{-}$) atoms from silica aerogel into vacuum was observed. Characteristics of muonium emission were established from silica aerogel samples with densities in the range from 29 mg cm$^{-3}$ to 178 mg cm$^{-3}$. Spectra of muonium decay times correlated with distances from the aerogel surfaces, which are sensitive to the speed distributions, follow general features expected from a diffusion process, while small deviations from a simple room-temperature thermal diffusion model are identified. The parameters of the diffusion process are deduced from the observed yields.

  1. Lithium-Niobate-Silica Hybrid Whispering-Gallery-Mode Resonators.

    Science.gov (United States)

    Bo, Fang; Wang, Jie; Cui, Jiao; Ozdemir, Sahin Kaya; Kong, Yongfa; Zhang, Guoquan; Xu, Jingjun; Yang, Lan

    2015-12-22

    Lithium-niobate-silica hybrid resonators with quality factors higher than 10(5) are fabricated by depositing a layer of polycrystalline lithium niobate on the flat top surfaces of inverted-wedge silica microdisk resonators. All-optical modulation with improved performance over silica-only resonators and electro-optic modulation not achievable in silica-only resonators are realized in the hybrid resonators. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Synthesis of Various Silica Nanoparticles for Foam Stability

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Suk Bon; Yoon, Inho; Jung, Chonghun; Kim, Chorong; Choi, Wangkyu; Moon, Jeikwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    The synthesis of the non-porous silica nanoparticles with uniform sizes has been reported through the Sto ber method, the synthesis of meso porous silica nanoparticles with a specific morphology such as core-shell, rod-like, and hexagonal shapes is not so common. As a synthetic strategy for controlling the particle size, shape, and porosity, the synthesis of core-shell silicas with meso porous shells formed on silica particle cores through the self-assembly of silica precursor and organic templates or spherical meso porous silicas using modified Sto ber method was also reported. Recently, in an effort to reduce the amount of radioactive waste and enhance the decontamination efficiency during the decontamination process of nuclear facilities contaminated with radionuclides, a few research for the preparation of the decontamination foam containing solid nanoparticles has been reported. In this work, the silica nanoparticles with various sizes, shapes, and structures were synthesized based on the previous literatures. The resulting silica nanoparticles were used to investigate the effect of the nanoparticles on the foam stability. In a study on the foam stability using various silica nanoparticles, the results showed that the foam volume and liquid volume in foam was enhanced when using a smaller size and lower density of the silica nanoparticles. Silica nanoparticles with various sizes, shapes, and structures such as a non-porous, meso porous core-shell, and meso porous silica were synthesized to investigate the effect of the foam stability. The sizes and structural properties of the silica nanoparticles were easily controlled by varying the amount of silica precursor, surfactant, and ammonia solution as a basic catalyst. The foam prepared using various silica nanoparticles showed that foam the volume and liquid volume in the foam were enhanced when using a smaller size and lower density of the silica nanoparticles.

  3. Template directed synthesis of highly organized functional biomimetic silica nanostructures

    OpenAIRE

    Kind, Lucy

    2009-01-01

    Silica is an important mineral in technological and biological applications. Many protocols have been developed for the synthesis of complex silica architectures. Most prominent is the silicification approach, where polymers build up the templates for the revealed polymer/silica structures. The current thesis demonstrates that star-shaped polymers and block copolymers are efficient templates for the fabrication of silica particles with spherical or raspberry-like morphology....

  4. 36th Brazilian Workshop on Nuclear Physics

    CERN Document Server

    Brandão de Oliveira, José Roberto; Barbosa Shorto, Julian Marco; Higa, Renato

    2014-01-01

    The Brazilian Workshop on Nuclear Physics (RTFNB, acronym in Portuguese) is organized annually by the Brazilian Physics Society since 1978, in order to: promote Nuclear Physics research in the country; stimulate and reinforce collaborations among nuclear physicists from around the country; disseminate advances in nuclear physics research and its applications; disseminate, disclose and evaluate the scientific production in this field.

  5. The new Brazilian national forest inventory

    Science.gov (United States)

    Joberto V. de Freitas; Yeda M. M. de Oliveira; Doadi A. Brena; Guilherme L.A. Gomide; Jose Arimatea Silva; < i> et al< /i>

    2009-01-01

    The new Brazilian national forest inventory (NFI) is being planned to be carried out through five components: (1) general coordination, led by the Brazilian Forest Service; (2) vegetation mapping, which will serve as the basis for sample plot location; (3) field data collection; (4) landscape data collection of 10 x 10-km sample plots, based on high-resolution...

  6. Brazilian Studies and Brazilianists: Conceptual remarks

    Directory of Open Access Journals (Sweden)

    Vinicius Mariano de Carvalho

    2017-01-01

    Full Text Available This article discusses the concept of Brazilian Studies. It does not intend to outline a defence for a new discipline, or to propose paradigms for that elusive field called ‘area studies’. It will, bring some reflections on epistemological and methodological issues realted to what it is been called Brazilian Studies.

  7. Types and myths in Brazilian thought

    Directory of Open Access Journals (Sweden)

    Octavio Ianni

    2005-01-01

    Full Text Available "Ideal types" elaborated by different authors and that have become emblematic, notorious or even definitive, sometimes representing myths are quite frequent in Brazilian thought. That is the case of the bandeirantes (colonial crusaders, the gaúcho, Jeca Tatu, Macunaíma, cordial man and others. It is worth contemplating this aspect of Brazilian culture and thought.

  8. Sociocultural Influences on Brazilian Children's Drawings.

    Science.gov (United States)

    Stokrocki, Mary

    2000-01-01

    Reports on insights about sociocultural influences on Brazilian children's drawings, using visual anthropology to examine children's drawings that depicted what they like to do. Discusses visual anthropology, provides information on Brazilian educational influences, and presents the context and findings of the study. (CMK)

  9. Rice saabus Euroopat taltsutama / Tõnu Prei

    Index Scriptorium Estoniae

    Prei, Tõnu, 1950-

    2005-01-01

    USA välisminister Condolezza Rice alustas ringreisi Euroopas, eesmärgiks anda vastulöök USA-d tabanud kriitikale sõjavangide kohtlemise ja teistes riikides oma luuretalituse salavanglate pidamise pärast

  10. Hunting Plan : Rice Lake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The objectives of this hunting plan for Rice Lake NWR are to: provide a method of removing white-tailed deer from the area population to maintain the general health...

  11. Reciprocating Internal Combustion Engines (RICE) | New ...

    Science.gov (United States)

    2017-05-25

    RICE use pistons that alternatively move back and forth to convert pressure into rotating motion. They're commonly used at power and manufacturing plants to generate electricity and to power pumps and compressors.

  12. [Red yeast rice: An unsafe food supplement?

    Science.gov (United States)

    Steffen, Christian

    2017-03-01

    Red yeast rice is the fermentation product of the mould Monascus ruber and is traditionally used in East Asia to dye and conserve food. Its main pharmacologically active compound, monakolin K, was isolated from red yeast rice and is used as an inhibitor of cholesterol synthesis under the INN lovastatin. Lovastatin and several other statins are marketed as drugs whereas red yeast rice is offered as a food supplement. As statins can cause severe side effects, such as muscle damage and kidney failure, the dosing and information about interactions with drugs and food is essential for the use of these products. Furthermore, red yeast rice can contain the mycotoxin citrinin and several other substances that are not yet toxicologically evaluated.

  13. USING RICE BRAN IN LAYING HEN DIETS

    Directory of Open Access Journals (Sweden)

    H ERSIN SAMLI

    2006-10-01

    Full Text Available Rice bran is an energy and protein rich ingredient used in poultry feeding. To balance energy and protein requirements. The purpose of this study is to examine the effects of rice bran on performance and egg quality during peak production of a commercial White laying strain of 22 week of age. Dietary treatments were consisted by inclusion of rice bran at 0, 5, 10 and 15% levels. Each treatment had 6 reps in which 12 birds were randomly assigned in wired fl oor battery cages equipped with nipple drinkers and through feeders. Layers accessed to feed and water freely. Lighting regimen was adjusted to 16h light/8h dark. The experiment lasted for 10 weeks. Overall results of the present experiment indicated that rice bran could be included up to 10% without any adverse affect on laying performance, egg quality and digestive organs.

  14. The Origin of Flooded Rice Cultivation

    Directory of Open Access Journals (Sweden)

    Hiroshi IKEHASHI

    2007-09-01

    Full Text Available Rice cultivation has long been considered to have originated from seeding of annual types of wild rice somewhere in subtropics, tropics or in the Yangtze River basin. That idea, however, contains a fatally weak point, when we consider the tremendous difficulty for primitive human to seed any cereal crop in the warm and humid climate, where weed thrives all year round. Instead of the accepted theory, we have to see a reality that vegetative propagation of edible plants is a dominant form of agriculture in such regions. The possibility is discussed that Job's tears and rice, two cereal crops unique to the region, might have been developed via vegetative propagation to obtain materials for medicine or herb tea in backyard gardens prior to cereal production. This idea is supported by the fact that rice in temperate regions is still perennial in its growth habit and that such backyard gardens with transplanted taro can still be seen from Yunnan Province of China to Laos. Thanks to detailed survey of wild rice throughout China for 1970–1980, it is now confirmed that a set of clones of wild rice exist in shallow swamps in Jiangxi Province, an area with severe winter cold. In early summer ancient farmers may have divided the sprouting buds and spread them by transplanting into flooded shallow marsh. Such way of propagation might have faster improved less productive rice through a better genetic potential for response to human interference than quick fixation in seed propagation, because vegetative parts are heterogeneous. Obviously, such a primitive manner of rice cultivation did include the essential parts of rice farming, i.e., nursery bed, transplanting in flooded field of shallow marsh like. Transfer from the primitive nursery to true nursery by seed may have later allowed rice cultivation to be extended to northern regions. In thus devised flooded cultivation there were a series of unique advantages, i.e.; continuous cropping of rice in a same

  15. improved performance of silica membranes for gas separation

    NARCIS (Netherlands)

    de Vos, R.M.; Verweij, H.

    1998-01-01

    Silica membranes with extremely low defect concentrations have been prepared using sol–gel synthesis starting from tetraethyl orthosilicate (TEOS). An asymmetric structure is obtained by applying two silica layers on top of a γ-Al2O3 layer, supported by an α-Al2O3 support. The selective silica top

  16. 78 FR 3449 - Silica Bricks and Shapes From China

    Science.gov (United States)

    2013-01-16

    ... COMMISSION Silica Bricks and Shapes From China Determination On the basis of the record \\1\\ developed in the... China of silica bricks and shapes, provided for in subheading 6902.20.10 of the Harmonized Tariff... injury by reason of LTFV imports of silica bricks and shapes from China. Accordingly, effective November...

  17. High export of dissolved silica from the Greenland Ice Sheet

    NARCIS (Netherlands)

    Meire, L.; Meire, P.; Struyf, E.; Krawczyk, D.W.; Arendt, K.E.; Yde, J.C.; Juul-Pedersen, T.; Hopwood, M.J.; Rysgaard, S.; Meysman, F.J.R.

    2016-01-01

    Silica is an essential element for marine life and plays a key role in the biogeochemistry of the ocean. Glacial activity stimulates rock weathering, generating dissolved silica that is exported to coastal areas along with meltwater. The magnitude of the dissolved silica export from large glacial

  18. Characterization of paralogous protein families in rice

    Directory of Open Access Journals (Sweden)

    Zhu Wei

    2008-02-01

    Full Text Available Abstract Background High gene numbers in plant genomes reflect polyploidy and major gene duplication events. Oryza sativa, cultivated rice, is a diploid monocotyledonous species with a ~390 Mb genome that has undergone segmental duplication of a substantial portion of its genome. This, coupled with other genetic events such as tandem duplications, has resulted in a substantial number of its genes, and resulting proteins, occurring in paralogous families. Results Using a computational pipeline that utilizes Pfam and novel protein domains, we characterized paralogous families in rice and compared these with paralogous families in the model dicotyledonous diploid species, Arabidopsis thaliana. Arabidopsis, which has undergone genome duplication as well, has a substantially smaller genome (~120 Mb and gene complement compared to rice. Overall, 53% and 68% of the non-transposable element-related rice and Arabidopsis proteins could be classified into paralogous protein families, respectively. Singleton and paralogous family genes differed substantially in their likelihood of encoding a protein of known or putative function; 26% and 66% of singleton genes compared to 73% and 96% of the paralogous family genes encode a known or putative protein in rice and Arabidopsis, respectively. Furthermore, a major skew in the distribution of specific gene function was observed; a total of 17 Gene Ontology categories in both rice and Arabidopsis were statistically significant in their differential distribution between paralogous family and singleton proteins. In contrast to mammalian organisms, we found that duplicated genes in rice and Arabidopsis tend to have more alternative splice forms. Using data from Massively Parallel Signature Sequencing, we show that a significant portion of the duplicated genes in rice show divergent expression although a correlation between sequence divergence and correlation of expression could be seen in very young genes. Conclusion

  19. Mycotoxin production on rice, pulses and oilseeds

    Science.gov (United States)

    Begum, Fouzia; Samajpati, N.

    Mycotoxin-producing fungi were isolated from contaminated grains of rice, pulses and oilseeds sold in the local markets of Calcutta for human consumption. It was found that aflatoxin B1 was produced by Aspergillus flavus and Aspergillus parasiticus, aflatoxin G1 by A. flavus, ochratoxin by Aspergillus ochraceous, sterigmatocystin by Aspergillus japonicus and citrinin by Penicillium citrinum. Aflatoxin B1 (333-10416μg/kg) was produced by Aspergillus spp. in rice, pulses and oilseeds.

  20. Polyamines and Anaerobic Elongation of Rice Coleoptile

    OpenAIRE

    Remo, Reggiani; Alejandro, Hochkoeppler; Alcide, Bertani; Istituto Biosintesi Vegetali, C. N. R.; Istituto Biosintesi Vegetali, C. N. R.; Istituto Biosintesi Vegetali, C. N. R.

    1989-01-01

    The role of polyamines in the anaerobic elongation of rice (Oryza sativa L.) coleoptiles was studied. The reduced growth of rice coleoptiles under anoxic conditions was accompanied by a massive accumulation of free putrescine. Putrescine was synthesized from arginine in a reaction catalyzed by arginine decarboxylase (ADC). The anoxic titer of putrescine was closely correlated with elongation of coleoptiles. In experiments in which putrescine and inhibitors [a-difluoromethylarginine (DFMA) and...

  1. The Potency of White Rice (Oryza sativa), Black Rice (Oryza sativa L. indica), and Red Rice (Oryza nivara) as Antioxidant and Tyrosinase Inhibitor

    Science.gov (United States)

    Batubara, I.; Maharni, M.; Sadiah, S.

    2017-04-01

    Rice is known to have many beneficial biological activities and is often used as “bedak dingin”, a face powder. The content of vitamins, minerals, fiber, and several types of antioxidants, such as ferulic acid, phytic acid, tocopherol, and oryzanols [1-2] are predicted to be potential as a tyrosinase inhibitor. The purpose of this study is to determine the potency of extracts from there types of rice, namely white, red, and black rice as an antioxidant and tyrosinase inhibitor. The rice was extracted with three different solvents, n-hexane, ethyl acetate, and methanol. The results showed that the highest antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl method was found in the methanol extract of black rice (IC50 290 μg/mL). Meanwhile, ethyl acetate extract of white rice has the highest antioxidant activity withphosphomolybdic acid method (41 mmol α-tocopherol equivalents/g sample). Thus, methanol extract of black rice and ethyl acetate extract of white rice are potential as an antioxidant. For tyrosinase inhibitor, n-hexane extract of red rice (IC50 3156 μg/mL) was the most active extract. The active component for radical scavenging is polar compound and for antioxidant by phosphomolybdate method is less polar compounds in black rice methanol extract based on TLC bioautogram. In conclusion, the black rice is the most potent in antioxidant while red rice is for tyrosinase inhibition.

  2. The Brazilian Synchrotron Light Source

    CERN Document Server

    Tavares, P F

    2005-01-01

    The Brazilian Synchrotron Radiation Laboratory has been operating the only light source in the southern hemisphere since July 1997. Over this 7 year period, approximately 22000 hours of beam time were delivered to users from all over Brazil as well as from 10 other countries. In this article, we report on the present configuration of the 1.37 GeV electron storage ring and associated instrumentation, describe recent improvements to the light source and analyze future prespectives including the installation of insertion devices and additional beamlines.

  3. Elementary education in brazilian legislation

    OpenAIRE

    Veronese, Josiane Rose Petry; Vieira, Cleverton Elias

    2003-01-01

    The education was a present subject, directly or indirectly, in every Brazilian Constitutions. In the Federal Constitution of 1988, two aspects about education can be detached: the participation of the civil society in the elaboration of devices that regulate the national education and the treatment given to basic education, raised to the category of subjective public right. Child and Adolescent Statute practically repeats the devices of the&n...

  4. Transcriptional profiling of rice early response to Magnaporthe oryzae identified OsWRKYs as important regulators in rice blast resistance.

    Directory of Open Access Journals (Sweden)

    Tong Wei

    Full Text Available Rice blast disease is a major threat to rice production worldwide, but the mechanisms underlying rice resistance to the causal agent Magnaporthe oryzae remain elusive. Therefore, we carried out a transcriptome study on rice early defense response to M. oryzae. We found that the transcriptional profiles of rice compatible and incompatible interactions with M. oryzae were mostly similar, with genes regulated more prominently in the incompatible interactions. The functional analysis showed that the genes involved in signaling and secondary metabolism were extensively up-regulated. In particular, WRKY transcription factor genes were significantly enriched among the up-regulated genes. Overexpressing one of these WRKY genes, OsWRKY47, in transgenic rice plants conferred enhanced resistance against rice blast fungus. Our results revealed the sophisticated transcriptional reprogramming of signaling and metabolic pathways during rice early response to M. oryzae and demonstrated the critical roles of WRKY transcription factors in rice blast resistance.

  5. Three geographically separate domestications of Asian rice.

    Science.gov (United States)

    Civáň, Peter; Craig, Hayley; Cox, Cymon J; Brown, Terence A

    2015-11-02

    Domesticated rice (Oryza sativa L.) accompanied the dawn of Asian civilization(1) and has become one of world's staple crops. From archaeological and genetic evidence various contradictory scenarios for the origin of different varieties of cultivated rice have been proposed, the most recent based on a single domestication(2,3). By examining the footprints of selection in the genomes of different cultivated rice types, we show that there were three independent domestications in different parts of Asia. We identify wild populations in southern China and the Yangtze valley as the source of the japonica gene pool, and populations in Indochina and the Brahmaputra valley as the source of the indica gene pool. We reveal a hitherto unrecognized origin for the aus variety in central India or Bangladesh. We also conclude that aromatic rice is a result of a hybridization between japonica and aus, and that the tropical and temperate versions of japonica are later adaptations of one crop. Our conclusions are in accord with archaeological evidence that suggests widespread origins of rice cultivation(1,4). We therefore anticipate that our results will stimulate a more productive collaboration between genetic and archaeological studies of rice domestication, and guide utilization of genetic resources in breeding programmes aimed at crop improvement.

  6. Drought Monitoring for Rice Production in Cambodia

    Directory of Open Access Journals (Sweden)

    Nyda Chhinh

    2015-10-01

    Full Text Available Rice production underpins the national economy and the most rural livelihoods in Cambodia, but it is negatively impacted by repeated droughts. The research reported on in this paper focuses on relationships between drought occurrences in Cambodia’s most drought-prone province (Kampong Speu and (i damage to the annual rice harvest between 1994 and 2011, and (ii the Niño 3.4 index. Droughts were identified using the Standardised Precipitation Index (SPI. In seven of the years between 1994 and 2006 droughts damaged >1000 ha of rice in the Kampong Speu province. Furthermore, in 11 years >200 ha of rice were damaged. A critical success index of 0.66 obtained for an analysis of SPI-defined drought and area rice damage in the province indicates a strong statistical relationship. A statistically significant correlation (r = −0.455 was achieved between Niño 3.4 and 12-month SPI values lagged by three months, this indicates the importance of ENSO linkages in explaining drought in this region. Late season droughts lead to greater rice damage than early- and mid-season droughts.

  7. Rice bran oil an alternate bakery shortening.

    Science.gov (United States)

    Kaur, Amarjeet; Jassal, Vishaldeep; Thind, S S; Aggarwal, Poonam

    2012-02-01

    Studies were carried out to replace bakery shortening with refined rice bran oil in bread preparation. Physico-chemical properties of bakery shortening and rice bran oil were studied. Rice bran oil was found to have a higher content of essential fatty acid linoleic acid (34.98%) as compared to that of bakery shortening (5.14%). Chemical composition of wheat flour used was also evaluation. Bread samples were prepared by replacing bakery shortening with rice bran oil at 0, 25, 50, 75 and 100% levels. Breads were examined for bread making quality i.e. loaf weight, loaf height, loaf volume and specific volume and organoleptic quality i.e. appearance, crust colour, crumb colour, aroma, texture, taste and overall acceptability on a 9 point hedonic scale. Statistical analysis regarding bread making quality and organoleptic quality of bread revealed that bread making and organoleptic quality of breads prepared after replacing bakery shortening with rice bran oil at 50% level varied significantly from that of control. Statistically significant variations were observed in the texture of breads prepared with shortening from that prepared after replacing bakery shortening with rice bran oil at 50% level.

  8. The structure of rice weevil pectin methylesterase.

    Science.gov (United States)

    Teller, David C; Behnke, Craig A; Pappan, Kirk; Shen, Zicheng; Reese, John C; Reeck, Gerald R; Stenkamp, Ronald E

    2014-11-01

    Rice weevils (Sitophilus oryzae) use a pectin methylesterase (EC 3.1.1.11), along with other enzymes, to digest cell walls in cereal grains. The enzyme is a right-handed β-helix protein, but is circularly permuted relative to plant and bacterial pectin methylesterases, as shown by the crystal structure determination reported here. This is the first structure of an animal pectin methylesterase. Diffraction data were collected to 1.8 Å resolution some time ago for this crystal form, but structure solution required the use of molecular-replacement techniques that have been developed and similar structures that have been deposited in the last 15 years. Comparison of the structure of the rice weevil pectin methylesterase with that from Dickeya dandantii (formerly Erwinia chrysanthemi) indicates that the reaction mechanisms are the same for the insect, plant and bacterial pectin methylesterases. The similarity of the structure of the rice weevil enzyme to the Escherichia coli lipoprotein YbhC suggests that the evolutionary origin of the rice weevil enzyme was a bacterial lipoprotein, the gene for which was transferred to a primitive ancestor of modern weevils and other Curculionidae. Structural comparison of the rice weevil pectin methylesterase with plant and bacterial enzymes demonstrates that the rice weevil protein is circularly permuted relative to the plant and bacterial molecules.

  9. Fungicide and insecticide residues in rice grains

    Directory of Open Access Journals (Sweden)

    Gustavo Mack Teló

    2017-01-01

    Full Text Available The objective of this study was to analyse residues of fungicides and insecticides in rice grains that were subjected to different forms of processing. Field work was conducted during three crop seasons, and fungicides and insecticides were applied at different crop growth stages on the aerial portion of the rice plants. Azoxystrobin, difenoconazole, propiconazole, tebuconazole, and trifloxystrobin fungicides were sprayed only once at the R2 growth stage or twice at the R2 and R4 growth stages; cypermethrin, lambda-cyhalothrin, permethrin, and thiamethoxam insecticides were sprayed at the R2 growth stage; and permethrin was sprayed at 5-day intervals from the R4 growth stage up to one day prior to harvest. Pesticide residues were analysed in uncooked, cooked, parboiled, polished and brown rice grains as well as rice hulls during the three crop seasons, for a total of 1458 samples. The samples were analysed by gas chromatography with electron capture detection (GC-ECD using modified QuEChERS as the extraction method. No fungicide or insecticide residues were detected in rice grain samples; however, azoxystrobin and cypermethrin residues were detected in rice hull samples.

  10. Pathways of Rice Diversification across Asia

    Directory of Open Access Journals (Sweden)

    Dorian Q Fuller

    2016-12-01

    Full Text Available The archaeology of rice has made important methodological advances over the past decade that have contributed new data on the domestication process, spread and ecology of cultivation. Growing evidence from spikelet bases indicates that non-shattering, domesticated forms evolved gradually in the Yangtze basin and that there were at least two distinct processes around the Middle Yangtze region pre-dating 6000 BC, and the in the Lower Yangtze region between 6000 and 4000 BC. Early rice cultivation in these areas was based on wet field ecologies, in contrast to rainfed rice that is indicated among the earliest systems in India. When rice first spread north it was not entirely suited to shorter temperate summer growth seasons, and we are able to infer from high levels of apparently green-harvested spikelets that genetic adaptations to temperate conditions evolved after 2000 BC. When rice first spread south, to mainland Southeast Asia, after 2500 BC, it was grown in rainfed, dry ecologies that were less labour- demanding and less-productive. More productive and intensive irrigated rice then redeveloped in Southeast Asia around 2000 years ago, supporting growing population densities and social complexity.

  11. Biomass saccharification is largely enhanced by altering wall polymer features and reducing silicon accumulation in rice cultivars harvested from nitrogen fertilizer supply.

    Science.gov (United States)

    Zahoor; Sun, Dan; Li, Ying; Wang, Jing; Tu, Yuanyuan; Wang, Yanting; Hu, Zhen; Zhou, Shiguang; Wang, Lingqiang; Xie, Guosheng; Huang, Jianliang; Alam, Aftab; Peng, Liangcai

    2017-11-01

    In this study, two rice cultivars were collected from experimental fields with seven nitrogen fertilizer treatments. All biomass samples contained significantly increased cellulose contents and reduced silica levels, with variable amounts of hemicellulose and lignin from different nitrogen treatments. Under chemical (NaOH, CaO, H2SO4) and physical (hot water) pretreatments, biomass samples exhibited much enhanced hexoses yields from enzymatic hydrolysis, with high bioethanol production from yeast fermentation. Notably, both degree of polymerization (DP) of cellulose and xylose/arabinose (Xyl/Ara) ratio of hemicellulose were reduced in biomass residues, whereas other wall polymer features (cellulose crystallinity and monolignol proportion) were variable. Integrative analysis indicated that cellulose DP, hemicellulosic Xyl/Ara and silica are the major factors that significantly affect cellulose crystallinity and biomass saccharification. Hence, this study has demonstrated that nitrogen fertilizer supply could largely enhance biomass saccharification in rice cultivars, mainly by reducing cellulose DP, hemicellulosic Xyl/Ara and silica in cell walls. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Health hazards due to the inhalation of amorphous silica.

    Science.gov (United States)

    Merget, R; Bauer, T; Küpper, H U; Philippou, S; Bauer, H D; Breitstadt, R; Bruening, T

    2002-01-01

    Occupational exposure to crystalline silica dust is associated with an increased risk for pulmonary diseases such as silicosis, tuberculosis, chronic bronchitis, chronic obstructive pulmonary disease (COPD) and lung cancer. This review summarizes the current knowledge about the health effects of amorphous (non-crystalline) forms of silica. The major problem in the assessment of health effects of amorphous silica is its contamination with crystalline silica. This applies particularly to well-documented pneumoconiosis among diatomaceous earth workers. Intentionally manufactured synthetic amorphous silicas are without contamination of crystalline silica. These synthetic forms may be classified as (1) wet process silica, (2) pyrogenic ("thermal" or "fumed") silica, and (3) chemically or physically modified silica. According to the different physicochemical properties, the major classes of synthetic amorphous silica are used in a variety of products, e.g. as fillers in the rubber industry, in tyre compounds, as free-flow and anti-caking agents in powder materials, and as liquid carriers, particularly in the manufacture of animal feed and agrochemicals; other uses are found in toothpaste additives, paints, silicon rubber, insulation material, liquid systems in coatings, adhesives, printing inks, plastisol car undercoats, and cosmetics. Animal inhalation studies with intentionally manufactured synthetic amorphous silica showed at least partially reversible inflammation, granuloma formation and emphysema, but no progressive fibrosis of the lungs. Epidemiological studies do not support the hypothesis that amorphous silicas have any relevant potential to induce fibrosis in workers with high occupational exposure to these substances, although one study disclosed four cases with silicosis among subjects exposed to apparently non-contaminated amorphous silica. Since the data have been limited, a risk of chronic bronchitis, COPD or emphysema cannot be excluded. There is no study

  13. Preparation and characterization of clay bonded high strength silica refractory by utilizing agriculture waste

    Directory of Open Access Journals (Sweden)

    Aman Bhardwaj

    2017-11-01

    Full Text Available Clay bonded silica refractory was prepared by utilizing agriculture waste called rice husk ash (RHA and refractory grog. Various samples were prepared with different compositions based upon partial replacement of quartz by RHA. Rectangular samples were prepared by following semi dry process prior to pressing in a uniaxial hydraulic press and sintering at a temperature of 1200 °C in air atmosphere. Various physical, mechanical and thermal characterizations were done like X-ray diffraction (XRD, scanning electron microscope (SEM, apparent porosity (AP, bulk density (BD, cold crushing strength (CCS, refractoriness and thermal conductivity measurement. The sample utilizing 30% of RHA was considered most optimum composition which produced cold crushing strength of 38 MPa and thermal conductivity of 2.08 W/m K at 800 °C with a considerable good refractoriness. Enhancement in the mechanical as well as thermal properties may be considered as attributed to the amorphous silica which has reacted more easily and efficiently with other material surrounding giving rise to the densification and produced stable crystalline phase to the refractory material. These promising characteristics suggests that the RHA may lead to be used as a potential material for the preparation of clay bonded high strength silica refractories. Resumen: Se preparó sílice refractaria unida a arcilla con residuos agrícolas conocidos como ceniza de cascarilla de arroz (rice husk ash [RHA] y grog refractario. Se prepararon varias muestras con diferentes composiciones basadas en la sustitución parcial de cuarzo por RHA. Las muestras rectangulares se prepararon siguiendo un proceso semiseco antes de prensarlas en una prensa hidráulica uniaxial y sinterizarlas a una temperatura de 1.200 °C en atmósfera de aire. Se realizaron diversas caracterizaciones físicas, mecánicas y térmicas, como la difracción de rayos X, el microscopio electrónico de barrido, la porosidad

  14. Effect of red rice interference in fourth densities of commercial rice.

    Directory of Open Access Journals (Sweden)

    Jorge García de la Osa

    2011-12-01

    Full Text Available Field trials were carried out in The Regional Research Grain Station “Sur del Jíbaro”, Sancti Spíritus, in order to study the infestation effect of 0, 12, 25, 50, 100 and 200 red rice plants per square meter (m2 on growth and yields of commercial variety J-104, seeded at 50, 100, 200 and 300 plants/m². Yield of J-104 rice variety decreased with the increase in red rice density. Crop yield decrease in the dry season ranged from 10.7 to 94.8% with infestations of 12 and 200 red rice plants /m², respectively; while in the wet season changed from 11.4 to 91.5 % with similar level in infestations. In both seasons 12 red rice plants were enough to cause a significant reduction in commercial rice yields in relation to the control treatment (without red rice infestation. The lost in crop yield was due to the decreased in panicles/ m² and filled grains per panicle, caused by the interference with red rice.

  15. evaluation of rice cultivars for resistance to rice yellow mottle virus ...

    African Journals Online (AJOL)

    ACSS

    2018-02-08

    Feb 8, 2018 ... H. KAM, M.-N. NDJIONDJOP1, N. OUEDRAOGO, M.D. LAING2 and A. GHESQUIERE3. Environmental and Agricultural Research Institute (INERA), 01 910 Bobo - Dioulasso, Burkina Faso. 1Africa Rice Center (AfricaRice), 01 BP 2551 Bouaké, Côte d'Ivoire. 2University of KwaZulu-Natal (UKZN), School of ...

  16. Rice-eating quality among consumers in different rice grain preference countries

    NARCIS (Netherlands)

    Suwannaporn, P.; Linnemann, A.R.

    2008-01-01

    More rice is eaten nowadays in traditionally nonrice-eating countries. This study investigated consumer eating quality preferences among consumers in target rice export countries to identify opportunities and strategic implications. A quantitative study with 1,128 consumers of target nationalities

  17. The Potential of System of Rice Intensification (SRI) to Increase Rice ...

    African Journals Online (AJOL)

    SRI practice for planting space of 25x25 to 30x30 cm, wetting and drying interval of three days, and younger seedling of 8-12 days are recommended as good combinations for SRI practice in Mkindo area, Morogoro region. Key words: Climate change, rice productivity, System of Rice Intensification (SRI), alternate wetting ...

  18. Complexity of rice Hsp100 gene family: lessons from rice genome ...

    Indian Academy of Sciences (India)

    2007-03-29

    Mar 29, 2007 ... Home; Journals; Journal of Biosciences; Volume 32; Issue 3. Complexity of rice Hsp100 gene family: lessons from rice genome sequence data. Gaurav Batra ... Elucidation of genome sequence provides an excellent platform to understand detailed complexity of the various gene families. Hsp100 is an ...

  19. Development and characterization of emulsions containing purple rice bran and brown rice oils

    Science.gov (United States)

    The aims of this study were to characterize purple rice bran oil (PRBO) as extracted from the bran, and to produce and characterize a nano-emulsion containing purple rice bran oil. An emulsion was prepared using PRBO (10%), sodium caseinate (5%) and water (85%). The mixture was sonicated followed ...

  20. Simultaneous rough rice drying and rice bran stabilization using infrared radiation heating

    Science.gov (United States)

    The objective of this study was to develop a new rice drying method by using IR heating followed by tempering. Freshly harvested medium grain rice (M206) samples with different initial moisture contents (IMCs) were used in this study. The samples were dried for one- and two-passes by using a catalyt...

  1. Silica sand resources in the Netherlands

    NARCIS (Netherlands)

    Meulen, M.J. van der; Westerhoff, W.E.; Menkovic, A.; Gruijters, S.H.L.L.; Dubelaar, C.W.; Maljers, D.

    2009-01-01

    Silica sand, (almost) pure quartz sand, is a valuable and scarce mineral resource within the shallow Dutch subsurface. High-grade deposits are exploited in the southeastemmost part of the country, as raw material for the glass, ceramic, chemical and other process industries. Dutch land-use policy

  2. Anisotropic silica mesostructures for DNA encapsulation

    Indian Academy of Sciences (India)

    The encapsulation of biomolecules in inert meso or nanostructures is an important step towards controlling drug delivery agents. Mesoporous silica nanoparticles (MSN) are of immense importance owing to their high surface area, large pore size, uniform particle size and chemical inertness. Reverse micellar method with ...

  3. High effective silica fume alkali activator

    Indian Academy of Sciences (India)

    Unknown

    ⋅03; C2S–27⋅90; C4AF–10⋅21. Figure 1. Development of compressive strength of mortars depending on the alkali activator used and the composition of the binder and the time of hardening. 1. Slag + NaOH; 2. Silica fume activator + slag; 3.

  4. Mesoporous silica nanoparticles for active corrosion protection.

    Science.gov (United States)

    Borisova, Dimitriya; Möhwald, Helmuth; Shchukin, Dmitry G

    2011-03-22

    This work presents the synthesis of monodisperse, mesoporous silica nanoparticles and their application as nanocontainers loaded with corrosion inhibitor (1H-benzotriazole (BTA)) and embedded in hybrid SiOx/ZrOx sol-gel coating for the corrosion protection of aluminum alloy. The developed porous system of mechanically stable silica nanoparticles exhibits high surface area (∼1000 m2·g(-1)), narrow pore size distribution (d∼3 nm), and large pore volume (∼1 mL·g(-1)). As a result, a sufficiently high uptake and storage of the corrosion inhibitor in the mesoporous nanocontainers was achieved. The successful embedding and homogeneous distribution of the BTA-loaded monodisperse silica nanocontainers in the passive anticorrosive SiOx/ZrOx film improve the wet corrosion resistance of the aluminum alloy AA2024 in 0.1 M sodium chloride solution. The enhanced corrosion protection of this newly developed active system in comparison to the passive sol-gel coating was observed during a simulated corrosion process by the scanning vibrating electrode technique (SVET). These results, as well as the controlled pH-dependent release of BTA from the mesoporous silica nanocontainers without additional polyelectrolyte shell, suggest an inhibitor release triggered by the corrosion process leading to a self-healing effect.

  5. Silica incorporated membrane for wastewater based filtration

    Science.gov (United States)

    Fernandes, C. S.; Bilad, M. R.; Nordin, N. A. H. M.

    2017-10-01

    Membrane technology has long been applied for waste water treatment industries due to its numerous advantages compared to other conventional processes. However, the biggest challenge in pressure driven membrane process is membrane fouling. Fouling decreases the productivity and efficiency of the filtration, reduces the lifespan of the membrane and reduces the overall efficiency of water treatment processes. In this study, a novel membrane material is developed for water filtration. The developed membrane incorporates silica nanoparticles mainly to improve its structural properties. Membranes with different loadings of silica nanoparticles were applied in this study. The result shows an increase in clean water permeability and filterability of the membrane for treating activated sludge, microalgae solution, secondary effluent and raw sewage as feed. Adding silica into the membrane matrix does not significantly alter contact angle and membrane pore size. We believe that silica acts as an effective pore forming agent that increases the number of pores without significantly altering the pore sizes. A higher number of small pores on the surface of the membrane could reduce membrane fouling because of a low specific loading imposed to individual pores.

  6. Anisotropic silica mesostructures for DNA encapsulation

    Indian Academy of Sciences (India)

    ca nanostructures for DNA encapsulation studies and observed a loading capacity of ∼8 μg mg−1 of the sample. On functionalizing the pores of silica with amine group, the amount of DNA loaded on the rods decreases which is due to a reduction in the pore size upon grafting of amine groups. Keywords. Surfactant; reverse ...

  7. Test of a silica aerogel Cerenkov counter

    CERN Document Server

    Basile, M; Cifarelli, L; Genovese, F; Giusti, P; Massam, Thomas; Massera, F; Palmonari, F; Romeo, G C; Valenti, G; Zichichi, A

    1977-01-01

    The authors have been able to produce samples of silica aerogels. The results of a systematic study of a sample with 4.5 cm diameter and 1.8 cm thickness and refractive index n=1.029+or-0.002 are reported. (5 refs).

  8. Nanostructured Mesoporous Silicas for Bone Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    Isabel Izquierdo-Barba

    2008-01-01

    Full Text Available The research on the development of new biomaterials that promote bone tissue regeneration is receiving great interest by the biomedical scientific community. Recent advances in nanotechnology have allowed the design of materials with nanostructure similar to that of natural bone. These materials can promote new bone formation by inducing the formation of nanocrystalline apatites analogous to the mineral phase of natural bone onto their surfaces, i.e. they are bioactive. They also stimulate osteoblast proliferation and differentiation and, therefore, accelerate the healing processes. Silica-based ordered mesoporous materials are excellent candidates to be used as third generation bioceramics that enable the adsorption and local control release of biological active agents that promote bone regeneration. This local delivery capability together with the bioactive behavior of mesoporous silicas opens up promising expectations in the bioclinical field. In this review, the last advances in nanochemistry aimed at designing and tailoring the chemical and textural properties of mesoporous silicas for biomedical applications are described. The recent developed strategies to synthesize bioactive glasses with ordered mesopore arrangements are also summarized. Finally, a deep discussion about the influence of the textural parameters and organic modification of mesoporous silicas on molecules adsorption and controlled release is performed.

  9. Optical recording in copper–silica nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Dmitruk, Igor, E-mail: igor_dmitruk@univ.kiev.ua [Femtosecond Laser Complex, Institute of Physics, National Academy of Sciences of Ukraine, 46 Prospect Nauky, 03028 Kyiv (Ukraine); Faculty of Physics, Taras Shevchenko National University of Kyiv, 60 Volodymyrska Street, 01601 Kyiv (Ukraine); Blonskiy, Ivan; Korenyuk, Petro; Kadan, Viktor; Zubrilin, Mykola; Dmytruk, Andriy [Femtosecond Laser Complex, Institute of Physics, National Academy of Sciences of Ukraine, 46 Prospect Nauky, 03028 Kyiv (Ukraine); Yeshchenko, Oleg [Faculty of Physics, Taras Shevchenko National University of Kyiv, 60 Volodymyrska Street, 01601 Kyiv (Ukraine); Alexeenko, Alexandr [P. O. Sukhoi State Technical University of Gomel, 48, Pr.Octiabria, 246746 Gomel (Belarus); Kotko, Andriy [I. M. Frantsevich Institute for Problems of Materials Science, 3, Krzhizhanovsky Str., 03680 Kyiv (Ukraine)

    2014-05-01

    The application of field enhancement effect, which takes place when light, interacts with surface plasmon, for optical recording has been suggested. Copper–silica nanocomposite demonstrates possibility of optical writing and erasing under irradiation by second harmonic (400 nm) and fundamental wavelength (800 nm) of femtosecond titanium–sapphire laser, respectively.

  10. Adsorption of Cadmium By Silica Chitosan

    Directory of Open Access Journals (Sweden)

    Moftah Ali

    2013-03-01

    Full Text Available The adsorption process depends on initial concentration of Cd2+ and ratio of  chitosan in adsorbent. The present study deals with the competitive adsorption of Cd2+ ion onto silica graft with chitosan. Batch adsorption experiments were performed at five different initial Cd2+ concentrations (5, 10, 15, 20 and 25 ppm, on five different proportion from silica to chitosan (100%, 95%, 85%, 75% and 65% as adsorbent at pH 5. In the recovery process, the high recovery at 0.5 mg and observed the recovery decrease with increasing the initial concentration of Cd2+, and the low recovery at 0.25 mg from Cd2+. In this study, the adsorption capacity of Cd2+ in regard to the ratio of silica and chitosan hybrid adsorbents are examined in detail. The aim of this study to explore effects of initial concentrations of Cd2+, and the ratio of silica to chitosan on the adsorption and recovery of Cd2+.

  11. Photo darkening of rare earth doped silica

    DEFF Research Database (Denmark)

    Mattsson, Kent Erik

    2011-01-01

    The photo darkening (PD) absorption spectra from unseeded amplifier operation (by 915 nm pumping) of ytterbium/aluminum and codoped silica fibers is after prolonged operation observed to develop a characteristic line at 2.6 eV (477 nm). This line is proposed to be due to inter center excitation t...

  12. Performance Characteristics of Silane Silica Modified Asphalt

    Directory of Open Access Journals (Sweden)

    Xuedong Guo

    2016-01-01

    Full Text Available At present there are many kinds of fillers and modifier used for modified asphalt, but the effect of modifier differs in thousands of ways; most of them can increase the high temperature performance of asphalt, but the modified effect of low-temperature crack resistance, water stability, and antifatigue performance is different. Aiming at the subsistent problems, this paper innovatively puts forward the idea of taking the silane silica (nanosilica modified with silane coupling agent as filler to develop one kind of modified asphalt concrete which has excellent comprehensive performance based on the idea of enhance the whole performance of asphalt concrete and interface consolidation strength between aggregate and asphalt at the same time. The best mixing amount of silane silica and the production process of modified asphalt were conducted by contrasting the test date as penetration, viscosity, and softening point; the aging of asphalt and modified asphalt was analyzed by TG test, the superiority of silane silica modified asphalt is more clearly understandable by chemical analysis results. Meanwhile it is proved that silane silica has positive effect to improve the mixture of high and low temperature performance, water stability, and aging resistance through a series of road performance tests.

  13. hydrophobic silica membranes for gas separation

    NARCIS (Netherlands)

    de Vos, R.M.; Maier, Wilhelm F.; Verweij, H.

    1999-01-01

    The synthesis and properties of hydrophobic silica membranes are described. These membranes show very high gas permeance for small molecules, such as H2, CO2, N2, O2, and CH4, and permselectivities of 20–50 for these gases with respect to SF6 and larger alkanes like C3H8 and i-C4H10. The membranes

  14. Mass transport in thin supported silica membranes

    NARCIS (Netherlands)

    Benes, Nieck Edwin

    2000-01-01

    In this thesis multi-component mass transport in thin supported amorphous silica membranes is discussed. These membranes are micro-porous, with pore diameters smaller than 4Å and show high fluxes for small molecules (such as hydrogen) combined with high selectivities for these molecules with respect

  15. Comparison of postmenopausal endogenous sex hormones among Japanese, Japanese Brazilians, and non-Japanese Brazilians

    Directory of Open Access Journals (Sweden)

    Maciel Maria

    2011-02-01

    Full Text Available Abstract Background Differences in sex hormone levels among populations might contribute to the variation in breast cancer incidence across countries. Previous studies have shown higher breast cancer incidence and mortality among Japanese Brazilians than among Japanese. To clarify the difference in hormone levels among populations, we compared postmenopausal endogenous sex hormone levels among Japanese living in Japan, Japanese Brazilians living in the state of São Paulo, and non-Japanese Brazilians living in the state of São Paulo. Methods A cross-sectional study was conducted using a control group of case-control studies in Nagano, Japan, and São Paulo, Brazil. Participants were postmenopausal women older than 55 years of age who provided blood samples. We measured estradiol, estrone, androstenedione, dehydroepiandrosterone sulfate (DHEAS, testosterone and free testosterone by radioimmunoassay; bioavailable estradiol by the ammonium sulfate precipitation method; and sex hormone-binding globulin (SHBG by immunoradiometric assay. A total of 363 women were included for the present analyses, comprising 185 Japanese, 44 Japanese Brazilians and 134 non-Japanese Brazilians. Results Japanese Brazilians had significantly higher levels of estradiol, bioavailable estradiol, estrone, testosterone and free testosterone levels, and lower SHBG levels, than Japanese. Japanese Brazilians also had significantly higher levels of bioavailable estradiol, estrone and DHEAS and lower levels of SHBG and androstenedione than non-Japanese Brazilians. Levels of estradiol, testosterone and free testosterone, however, did not differ between Japanese Brazilians and non-Japanese Brazilians. These differences were observed even after adjustment for known breast cancer risk factors. We also found an increase in estrogen and androgen levels with increasing body mass index, but no association for most of the other known risk factors. Conclusions We found higher levels of

  16. Alkali-activated binder containing wastes: a study with rice husk ash and red ceramic

    Directory of Open Access Journals (Sweden)

    R. H. Geraldo

    Full Text Available Abstract In addition to several positive aspects in technical properties, geopolymeric binders have considerable advantages in the environmental point of view, with lower energy consumption and lower CO2 emission. In this study, it was conducted an overview about the utilized materials by some Brazilian researchers in geopolymers production, and also an experiment employing two types of wastes (red ceramic waste and rice husk ash. The compressive strength of the resulting material developed very fast, reaching a value of 11 MPa after one day. The microstructure was evaluated by scanning electron microscopy, revealing a compact microstructure and the presence of starting materials from the red ceramic waste that not completely reacted. The results indicated the feasibility of producing geopolymeric material without using commercial sodium silicate and cured at room temperature, showing an option for building materials production with lower environmental impacts.

  17. The phylogeography of African Brazilians.

    Science.gov (United States)

    Gonçalves, Vanessa F; Carvalho, Cláudia M B; Bortolini, Maria Cátira; Bydlowski, Sérgio P; Pena, Sérgio D J

    2008-01-01

    Approximately four million Africans were taken as slaves to Brazil, where they interbred extensively with Amerindians and Europeans. We have previously shown that while most White Brazilians carry Y chromosomes of European origin, they display high proportions of African and Amerindian mtDNA lineages, because of sex-biased genetic admixture. We studied the Y chromosome and mtDNA haplogroup structure of 120 Black males from Sao Paulo, Brazil. Only 48% of the Y chromosomes, but 85% of the mtDNA haplogroups were characteristic of sub-Saharan Africa, confirming our previous observation of sexually biased mating. We mined literature data for mtDNA and Y chromosome haplogroup frequencies for African native populations from regions involved in Atlantic Slave Trade. Principal Components Analysis and Bayesian analysis of population structure revealed no genetic differentiation of Y chromosome marker frequencies between the African regions. However, mtDNA examination unraveled considerable genetic structure, with three clusters at Central-West Africa, West Africa and Southeast Africa. A hypothesis is proposed to explain this structure. Using these mtDNA data we could obtain for the first time an estimate of the relative ancestral contribution of Central-West (0.445), West (0.431) and Southeast Africa (0.123) to African Brazilians from Sao Paulo. These estimates are consistent with historical information. Copyright 2008 S. Karger AG, Basel.

  18. Rice bran: a novel functional ingredient.

    Science.gov (United States)

    Sharif, Mian Kamran; Butt, Masood Sadiq; Anjum, Faqir Muhammad; Khan, Saima Hafiz

    2014-01-01

    Rice (Oryza sativa) is the most important staple food for a large part of the world's human population, especially in East and South Asia, the Middle East, Latin America, and the West Indies. It provides more than one fifth of the calories consumed worldwide by the human. It is the second leading cereal crop and staple food of half of the world's population. It is grown in at least 114 countries with global production of 645 million tons; share of Asian farmers is about 90% of the total produce. Rice bran, brown outer layer of rice kernel, is mainly composed of pericarp, aleurone, subaleurone layer, and germ. It contains appreciable quantities of nutrients like protein, fat, and dietary fiber. Furthermore, it contains substantial amount of minerals like K, Ca, Mg, and Fe. Presence of antioxidants like tocopherols, tocotrienols, and γ-oryzanol also brighten prospects of rice bran utilization for humans as functional ingredient to mitigate the life-threatening disorders. Moreover, in the developing countries, budding dilemma of food crisis, arising due to lower crop yields and escalating population, needs to utilize each pent of available resources. To provide enough food to all people, there is the holistic approach of using the by-products generated during food processing and preparations. Rice is being processed in well-established industry, but the major apprehension is the utilization of its by-products; rice bran (5-8%) and polishing (2-3%) that are going as waste. Rice processing or milling produces several streams of materials including milled rice, bran, and husk. In developing countries, rice bran is considered as a by-product of the milling process and commonly used in animal feed or discarded as a waste. The potential of producing rice bran at the global level is 29.3 million tons annually, whereas the share of Pakistan is worked out to be 0.5 million tons. In present paper, attempt has been made to highlight the significance of these valuable but

  19. Effect of Temperature on Chinese Rice Wine Brewing with High Concentration Presteamed Whole Sticky Rice

    Science.gov (United States)

    Zhang, Hong-Tao; Xiong, Weili; Hu, Jianhua; Xu, Baoguo; Lin, Chi-Chung; Xu, Ling; Jiang, Lihua

    2014-01-01

    Production of high quality Chinese rice wine largely depends on fermentation temperature. However, there is no report on the ethanol, sugars, and acids kinetics in the fermentation mash of Chinese rice wine treated at various temperatures. The effects of fermentation temperatures on Chinese rice wine quality were investigated. The compositions and concentrations of ethanol, sugars, glycerol, and organic acids in the mash of Chinese rice wine samples were determined by HPLC method. The highest ethanol concentration and the highest glycerol concentration both were attained at the fermentation mash treated at 23°C. The highest peak value of maltose (90 g/L) was obtained at 18°C. Lactic acid and acetic acid both achieved maximum values at 33°C. The experimental results indicated that temperature contributed significantly to the ethanol production, acid flavor contents, and sugar contents in the fermentation broth of the Chinese rice wines. PMID:24672788

  20. Can rice field channels contribute to biodiversity conservation in Southern Brazilian wetlands?

    Directory of Open Access Journals (Sweden)

    Leonardo Maltchik

    2011-12-01

    Full Text Available La conservación de especies en los agroecosistemas ha llamado la atención. Los canales de riego pueden mejorar los hábitats y ofrecer condiciones para la conservación de especies de agua dulce. Desde el punto de vista de conservación de la biodiversidad surgen dos preguntas: 1 ¿Pueden los canales de riego mantener una rica diversidad de vegetación acuática, invertebrados y anfibios en el ciclo de cultivo del arroz? 2 ¿Puede la riqueza, abundancia y composición de especies acuáticas cambiar durante el ciclo de cultivo del arroz? Para ello, en el Condado Mostardas, Brazil un grupo de cuatro canales de los campos de arroz fue seleccionado al azar. En cada canal, se llevaron a cabo seis muestreos durante el ciclo de cultivo del arroz (junio 2005 hasta junio 2006. Un total de 160 táxones fueron identificados en los canales de riego, que incluyen 59 especies de macrófitos, 91 táxones de macroinvertebrados y 10 especies de anfibios. La riqueza y la abundancia de vegetación acuática, invertebrados y anfibios no cambió significativamente durante el ciclo de cultivo del arroz. Sin embargo, la composición de las especies de estos grupos en los canales de riego varía entre períodos no cultivados y cultivados. Nuestros resultados muestran que la diversidad de especies en los canales de riego, junto con la permanencia del agua permite que estas redes acuáticas provocadas por el ser humano puedan funcionar como sistemas importantes que contribuyan con la conservación de la biodiversidad en las regiones donde los humedales se han convertido en campos de arroz. La conservación de las especies en la agricultura, tales como los campos de los canales de arroz, que pueden ser una alternativa importante para la conservación de la biodiversidad en el sur de Brasil, donde más del 90% de los sistemas de humedales ya se han perdido y los restantes aún se encuentran en alto riesgo debido a la expansión de la producción de arroz.

  1. Development of Ozone Technology Rice Storage Systems (OTRISS) for Quality Improvement of Rice Production

    Science.gov (United States)

    Nur, M.; Kusdiyantini, E.; Wuryanti, W.; Winarni, T. A.; Widyanto, S. A.; Muharam, H.

    2015-06-01

    This research has been carried out by using ozone to address the rapidly declining quality of rice in storage. In the first year, research has focused on the rice storage with ozone technology for small capacity (e.g., household) and the medium capacity (e.g., dormitories, hospitals). Ozone was produced by an ozone generator with Dielectric Barrier Discharge Plasma (DBDP). Ozone technology rice storage system (OTRISS) is using ozone charateristic which is a strong oxidizer. Ozone have a short endurance of existence and then decompose, as a result produce oxygen and radicals of oxygen. These characteristics could kill microorganisms and pests, reduce air humidity and enrich oxygen. All components used in SPBTO assembled using raw materials available in the big cities in Indonesia. Provider of high voltage (High Voltage Power Supply, 40-70 kV, 23 KH, AC) is one of components that have been assembled and tested. Ozone generator is assembled with 7 reactors of Dielectric Barrier Discharge Plasma (DBDP). Rice container that have been prepared for OTRISS have adjusted so can be integrated with generator, power supply and blower to blow air. OTRISS with a capacity of 75 kg and 100 kg have been made and tested. The ability of ozone to eliminate bacteria and fungi have been tested and resulted in a decrease of microorganisms at 3 log CFU/g. Testing in food chemistry showed that ozone treatment of rice had not changed the chemical content that still meet the standard of chemical content and nutritional applicable to ISO standard milled rice. The results of this study are very likely to be used as an alternative to rice storage systems in warehouse. Test and scale-up is being carried out in a mini warehouse whose condition is mimicked to rice in National Rice Storage of Indonesia (Bulog) to ensure quality. Next adaptations would be installed in the rice storage system in the Bulog.

  2. Integrated rice-duck farming mitigates the global warming potential in rice season.

    Science.gov (United States)

    Xu, Guochun; Liu, Xin; Wang, Qiangsheng; Yu, Xichen; Hang, Yuhao

    2017-01-01

    Integrated rice-duck farming (IRDF), as a mode of ecological agriculture, is an important way to realize sustainable development of agriculture. A 2-year split-plot field experiment was performed to evaluate the effects of IRDF on methane (CH4) and nitrous oxide (N2O) emissions and its ecological mechanism in rice season. This experiment was conducted with two rice farming systems (FS) of IRDF and conventional farming (CF) under four paddy-upland rotation systems (PUR): rice-fallow (RF), annual straw incorporating in rice-wheat rotation system (RWS), annual straw-based biogas residues incorporating in rice-wheat rotation system (RWB), and rice-green manure (RGM). During the rice growing seasons, IRDF decreased the CH4 emission by 8.80-16.68%, while increased the N2O emission by 4.23-15.20%, when compared to CF. Given that CH4 emission contributed to 85.83-96.22% of global warming potential (GWP), the strong reduction in CH4 emission led to a significantly lower GWP of IRDF as compared to CF. The reason for this trend was because IRDF has significant effect on dissolved oxygen (DO) and soil redox potential (Eh), which were two pivotal factors for CH4 and N2O emissions in this study. The IRDF not only mitigates the GWP, but also increases the rice yield by 0.76-2.43% compared to CF. Moreover, compared to RWS system, RF, RWB and RGM systems significantly reduced CH4 emission by 50.17%, 44.89% and 39.51%, respectively, while increased N2O emission by 10.58%, 14.60% and 23.90%, respectively. And RWS system had the highest GWP. These findings suggest that mitigating GWP and improving rice yield could be simultaneously achieved by the IRDF, and employing suitable PUR would benefit for relieving greenhouse effect. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Effect of silica particle size on macrophage inflammatory responses.

    Directory of Open Access Journals (Sweden)

    Toshimasa Kusaka

    Full Text Available Amorphous silica particles, such as nanoparticles (<100 nm diameter particles, are used in a wide variety of products, including pharmaceuticals, paints, cosmetics, and food. Nevertheless, the immunotoxicity of these particles and the relationship between silica particle size and pro-inflammatory activity are not fully understood. In this study, we addressed the relationship between the size of amorphous silica (particle dose, diameter, number, and surface area and the inflammatory activity (macrophage phagocytosis, inflammasome activation, IL-1β secretion, cell death and lung inflammation. Irrespective of diameter size, silica particles were efficiently internalized by mouse bone marrow-derived macrophages via an actin cytoskeleton-dependent pathway, and induced caspase-1, but not caspase-11, activation. Of note, 30 nm-1000 nm diameter silica particles induced lysosomal destabilization, cell death, and IL-1β secretion at markedly higher levels than did 3000 nm-10000 nm silica particles. Consistent with in vitro results, intra-tracheal administration of 30 nm silica particles into mice caused more severe lung inflammation than that of 3000 nm silica particles, as assessed by measurement of pro-inflammatory cytokines and neutrophil infiltration in bronchoalveolar lavage fluid of mice, and by the micro-computed tomography analysis. Taken together, these results suggest that silica particle size impacts immune responses, with submicron amorphous silica particles inducing higher inflammatory responses than silica particles over 1000 nm in size, which is ascribed not only to their ability to induce caspase-1 activation but also to their cytotoxicity.

  4. Nanometer Sized Silver Particles Embedded Silica Particles—Spray Method

    Directory of Open Access Journals (Sweden)

    Karunagaran B

    2009-01-01

    Full Text Available Abstract Spherical shaped, nanometer to micro meter sized silica particles were prepared in a homogeneous nature by spray technique. Silver nanoparticles were produced over the surface of the silica grains in a harmonized manner. The size of silver and silica particles was effectively controlled by the precursors and catalysts. The electrostatic repulsion among the silica spheres and the electro static attraction between silica spheres and silver particles make the synchronized structure of the synthesized particles and the morphological images are revealed by transmission electron microscope. The silver ions are reduced by sodium borohydride. Infra red spectroscopy and X-ray photoelectron spectroscopy analysis confirm the formation of silver–silica composite particles. Thermal stability of the prepared particles obtained from thermal analysis ensures its higher temperature applications. The resultant silver embedded silica particles can be easily suspended in diverse solvents and would be useful for variety of applications.

  5. Water Vapor Effects on Silica-Forming Ceramics

    Science.gov (United States)

    Opila, E. J.; Greenbauer-Seng, L. (Technical Monitor)

    2000-01-01

    Silica-forming ceramics such as SiC and Si3N4 are proposed for applications in combustion environments. These environments contain water vapor as a product of combustion. Oxidation of silica-formers is more rapid in water vapor than in oxygen. Parabolic oxidation rates increase with the water vapor partial pressure with a power law exponent value close to one. Molecular water vapor is therefore the mobile species in silica. Rapid oxidation rates and large amounts of gases generated during the oxidation reaction in high water vapor pressures may result in bubble formation in the silica and nonprotective scale formation. It is also shown that silica reacts with water vapor to form Si(OH)4(g). Silica volatility has been modeled using a laminar flow boundary layer controlled reaction equation. Silica volatility depends on the partial pressure of water vapor, the total pressure, and the gas velocity. Simultaneous oxidation and volatilization reactions have been modeled with paralinear kinetics.

  6. Brazilian scientific production on herbal medicines used in dentistry

    OpenAIRE

    R.D. Castro; J.A. Oliveira; Vasconcelos,L.C.; Maciel,P.P.; Brasil,V.L.M.

    2014-01-01

    The objective of this study was to critically analyze the scientific production published in specialized Brazilian journals concerning the use of medicinal plants in dentistry. A literature review was carried out using an indirect documentation technique by means of a bibliographical study. Four examiners performed independent searches in Brazilian journals of medicinal plants indexed in the database SciELO (Brazilian Journal of Pharmacognosy; Brazilian Journal of Medicinal Plants; Brazilian ...

  7. Genome-wide analysis of Dongxiang wild rice (Oryza rufipogon Griff.) to investigate lost/acquired genes during rice domestication.

    Science.gov (United States)

    Zhang, Fantao; Xu, Tao; Mao, Linyong; Yan, Shuangyong; Chen, Xiwen; Wu, Zhenfeng; Chen, Rui; Luo, Xiangdong; Xie, Jiankun; Gao, Shan

    2016-04-26

    It is widely accepted that cultivated rice (Oryza sativa L.) was domesticated from common wild rice (Oryza rufipogon Griff.). Compared to other studies which concentrate on rice origin, this study is to genetically elucidate the substantially phenotypic and physiological changes from wild rice to cultivated rice at the whole genome level. Instead of comparing two assembled genomes, this study directly compared the Dongxiang wild rice (DXWR) Illumina sequencing reads with the Nipponbare (O. sativa) complete genome without assembly of the DXWR genome. Based on the results from the comparative genomics analysis, structural variations (SVs) between DXWR and Nipponbare were determined to locate deleted genes which could have been acquired by Nipponbare during rice domestication. To overcome the limit of the SV detection, the DXWR transcriptome was also sequenced and compared with the Nipponbare transcriptome to discover the genes which could have been lost in DXWR during domestication. Both 1591 Nipponbare-acquired genes and 206 DXWR-lost transcripts were further analyzed using annotations from multiple sources. The NGS data are available in the NCBI SRA database with ID SRP070627. These results help better understanding the domestication from wild rice to cultivated rice at the whole genome level and provide a genomic data resource for rice genetic research or breeding. One finding confirmed transposable elements contribute greatly to the genome evolution from wild rice to cultivated rice. Another finding suggested the photophosphorylation and oxidative phosphorylation system in cultivated rice could have adapted to environmental changes simultaneously during domestication.

  8. Evaluating Welfare Effects of Rice Import Quota in Japan: Based on Measuring Non-Tariff Barriers of SBS Rice Imports

    Directory of Open Access Journals (Sweden)

    Qianhui Gao

    2016-08-01

    Full Text Available The principal objective of this study is to analyze welfare effects of Japan’s rice import quota focusing on the simultaneous buy and sell (SBS of the rice importation minimum access (MA policy. Based on the utility function specified in this study, the constructed model is adopted to measure consumption patterns through estimating elasticity of substitution between imported rice and Japan’s domestic rice, and consumers’ preference parameters for different kinds of rice. The results showed that Japanese households prefer domestic rice to the imported rice. Besides, three scenarios of adjusting rice quota volumes were carried out to examine the changes in consumer prices of imported rice and Japanese consumers’ welfares. The results revealed that tariff equivalents of the SBS import quota almost doubled the scale of the mark-up, and the intervention by the Ministry of Agriculture of Japan did cause non-tariff barriers to trade (NTBs. Finally, if the SBS rice quota quantity was fixed at or larger than 180 thousand tons every fiscal year, the consumer prices of imported rice in Japan’s market would decrease to be less than the prices of Japan’s domestic rice, and therefore the imported rice would have more price advantages in this scenario.

  9. Decreasing Rice Supply as the Impact Of The Government’s Policy on Rice Grain Purchasing Price

    Directory of Open Access Journals (Sweden)

    Retno Lantarsih

    2015-02-01

    Full Text Available This research aimed at examining: (1 rice supply adjustment for the long-term equilibrium (2 the impact of the government’s policies on rice grain purchasing price to the rice supply, (3 and factors influencing the long-term and short-term rice supply in the rice-producing regions in Indonesia. This research used the panel data regression with the error correction model approach. The data were the yearly time series data of 1987 through 2008. The results showed that (1 the rice supply adjustment for the long-term equilibrium was at 68%, (2 in the long term, the government’s policies on rice grain purchasing price reduced the rice supply, (3 in the long term, the rice retail price, the rain fall, and the technology had a positive influence on the rice supply, while the cassava and soybean prices had a negative influence. In the short term, the rice retail price and technology had a positive influence, while the cassava and soybean prices and the monetary crisis dummy had a negative influence to the rice supply in the rice-producing regions in Indonesia.

  10. Mutant Resources for the Functional Analysis of the Rice Genome

    National Research Council Canada - National Science Library

    Nili Wang Tuan Long Wen Yao Lizhong Xiong Qifa Zhang Changyin Wu

    2013-01-01

    .... In order to systematically assign functions to all predicted genes in the rice genome, a large number of rice mutant lines, including those created by T-DNA insertion, Ds/dSpm tagging, Tos17 tagging...

  11. Analysis of Energy Characteristics of Rice and Coffee Husks Blends

    National Research Council Canada - National Science Library

    Cuthbert F. Mhilu

    2014-01-01

    .... This paper reports work done to determine energy characteristics of rice and coffee husks. The results show that coffee husks have better energy quality than rice husks, while heating values of coffee are 18.34 MJ/kg...

  12. Phylogenetic diversity and relationships among 40 rice accessions ...

    African Journals Online (AJOL)

    SERVER

    , there is the need to diversify the genetic base of improved rice varieties, and the first step towards this is to evaluate and characterise available rice germplasm or genotypes at both the morphological and molecular levels. This is because the.

  13. Why Is Golden Rice Golden (Yellow) Instead of Red?

    National Research Council Canada - National Science Library

    Patrick Schaub; Salim Al-Babili; Rachel Drake; Peter Beyer

    2005-01-01

    The endosperm of Golden Rice (Oryza sativa) is yellow due to the accumulation of β-carotene (provitamin A) and xanthophylls. The product of the two carotenoid biosynthesis transgenes used in Golden Rice, phytoene synthase...

  14. Fisheries Management Plan: Rice Lake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Rice Lake National Wildlife Refuge provides a sport fishery on three of the four refuge lakes. Fishing is restricted to designated areas. Rice Lake, though not open...

  15. CHEMICAL COMPOSITION AND FUNCTIONAL PROPERTIES OF RICE PROTEIN CONCENTRATES

    National Research Council Canada - National Science Library

    V. V. Kolpakova; D. N. Lukin; L. V. Chumikina; L. V. Shevyakova

    2015-01-01

    .... The task of this study was a comparative research of nutrition and biological value and functional properties of protein and protein-calcium concentrates produced from rice flour milled from white and brown rice...

  16. 7 CFR 457.141 - Rice crop insurance provisions.

    Science.gov (United States)

    2010-01-01

    ... (Appropriate title for insurance provider) Both FCIC and Reinsured Policies Rice Crop Provisions If a conflict... Standards for Rice including, but not limited to, protein and oil content or milling quality will not be...

  17. THE BENTHIC COMMUNITIES COMPARISON BETWEEN ORGANIC AND CONVENTIONAL RICE FIELDS.

    Science.gov (United States)

    Kasamesiri, P; Thaimuangphol, W

    2015-01-01

    Rice fields are temporary wetlands prone to contamination from agricultural chemicals which affect their ecotoxicology and benthic community composition. The diversity of benthic fauna in both organic and conventional rice fields in Kalasin Province, Thailand was investigated. Benthos samples were collected by grab sampling from 20 stations in organic and conventional rice fields during one successive crop in August 2014. The number of benthic organisms found at each sampling station ranged from 16-518 and 24-137 individuals for organic and conventional rice fields, respectively. The benthic fauna in organic rice fields were dominated by crustaceans 41%, insects 31%, annelids 26%, and gastropods 2%. The conventional rice fields benthic fauna was composed of insects 51%, annelids 41%, and gastropods 8%. The abundance and composition of the benthic fauna demonstrated that organic rice farming practices are beneficial to sustaining the biodiversity in rice field ecosystems.

  18. Simulating rice yields under climate change scenarios using the ...

    African Journals Online (AJOL)

    %. Simulations demonstrate that the effects of planting dates cannot be overlooked in finding measures to increase rice yield under climate change mitigations. The effects of climate change on rice yield of will depend on the actual patterns of ...

  19. Comparative Economic Analysis of Rice Production by Adopters and ...

    African Journals Online (AJOL)

    adopters of improved rice varieties among farmers in Paikoro Local Area of Niger State. Primary data were collected using a structured questionnaire administered to 90 respondents, which consist of 45 adopters of improved rice variety and 45 ...

  20. Assessment of protection and comparative advantage in rice ...

    African Journals Online (AJOL)

    added rice as well as analyze the comparative advantage and competitiveness of rice processing in Nigeria. The extent of policy distortion and agricultural protection was also determined by the study. The data were collected from Ebonyi State, ...