Sample records for carbon disulphide impregnated

  1. Carbon disulphide promotes sprouting of potato minitubers

    NARCIS (Netherlands)

    Salimi, Kh.; Hosseini, M.B.; Struik, P.C.; Tavakkol Afshari, R.


    We investigated the effects of postharvest application of carbon disulphide (CS2) in various concentrations (0, 15, 25, 35, 45 and 55 ml m-3) and with different exposure duration (24, 48, 72 and 96 h) on breaking of dormancy and sprouting of potato (Solanum tuberosum L., cv. Marfona) minitubers of

  2. Electron irradiation of carbon dioxide-carbon disulphide ice analog ...

    Indian Academy of Sciences (India)

    Abstract. Carbon dioxide (CO2) and carbon disulphide (CS2) molecular ice mixture was prepared under low temperature (85 K) astrochemical conditions. The icy mixture irradiated with keV electrons simulates the irradiation environment experienced by icy satellites and Interstellar Icy Mantles (IIM). Upon electron irradi-.

  3. Spectrophotometric Determination of Carbon Disulphide in the Workplace Air

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    V. Pitschmann


    Full Text Available This papre describes a simple method of carbon disulphide determination in the air of working environment in the chemical companies and plants after its absorption into aprotic N,N-dimethylformamide solvent. Carbon disulphide absorbed into aprotic solvent was transformed by using ammonium hydroxide on sulphides which were determined by spectrophotometry. 5,5′-Dithiobis(2-nitrobenzoic acid and blue tetrazolium chloride were used as chromogenic sensing reagents. Colour-reducing products were measured at the wavelength of 500, respectively 520 nm. Detection limits for determination of carbon disulphide in the air are 0.2, respectively 0.4 mg·m−3.

  4. Impregnating Coal With Calcium Carbonate (United States)

    Sharma, Pramod K.; Voecks, Gerald E.; Gavalas, George R.


    Relatively inexpensive process proposed for impregnating coal with calcium carbonate to increase rates of gasification and combustion of coal and to reduce emission of sulfur by trapping sulfur in calcium sulfide. Process involves aqueous-phase reactions between carbon dioxide (contained within pore network of coal) and calcium acetate. Coal impregnated with CO2 by exposing it to CO2 at high pressure.

  5. Electron irradiation of carbon dioxide-carbon disulphide ice analog ...

    Indian Academy of Sciences (India)

    Upon electron irradiation the chemical composition was found to have altered and the new products from irradiation were found to be carbonyl sulphide (OCS), sulphur dioxide (SO2), ozone (O3), carbon trioxide (CO3), sulphur trioxide (SO3), carbon subsulphide (C3S2) and carbon monoxide (CO). Results obtained confirm ...

  6. Synthesis of silver impregnated carbon nanotubes and cyclodextrin ...

    African Journals Online (AJOL)

    Silver impregnated carbon nanotubes and cyclodextrin polymers were synthesised by first functionalising carbon nanotubes in a mixture of nitric and sulphuric acid before impregnating them with silver nanoparticles. The silver impregnated functionalised carbon nanotubes were then polymerised with β cyclodextrin using ...

  7. Fracture in Phenolic Impregnated Carbon Ablator (United States)

    Agrawal, Parul; Chavez-Garcia, Jose; Pham, John


    This paper describes the development of a novel technique to understand the failure mechanisms inside thermal protection materials. The focus of this research is on the class of materials known as phenolic impregnated carbon ablators. It has successfully flown on the Stardust spacecraft and is the thermal protection system material chosen for the Mars Science Laboratory and SpaceX Dragon spacecraft. Although it has good thermal properties, structurally, it is a weak material. To understand failure mechanisms in carbon ablators, fracture tests were performed on FiberForm(Registered TradeMark) (precursor), virgin, and charred ablator materials. Several samples of these materials were tested to investigate failure mechanisms at a microstructural scale. Stress-strain data were obtained simultaneously to estimate the tensile strength and toughness. It was observed that cracks initiated and grew in the FiberForm when a critical stress limit was reached such that the carbon fibers separated from the binder. However, both for virgin and charred carbon ablators, crack initiation and growth occurred in the matrix (phenolic) phase. Both virgin and charred carbon ablators showed greater strength values compared with FiberForm samples, confirming that the presence of the porous matrix helps in absorbing the fracture energy.

  8. Iron impregnated carbon materials with improved physicochemical characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Irfan; Adnan, Rohana, E-mail:; Wan Ngah, Wan Saime; Mohamed, Norita


    Highlights: • The morphology of raw AC was altered upon Fe impregnation and surface oxidation. • Surface modification had increased the pores diameter and surface functionalities. • Development of iron oxides have been expected on Fe impregnated carbon materials. • The M1, M2 and M3 have revealed magnetic susceptibility in applied magnetic field. • Dyes removal efficiency of M3 was notably higher (90–99%) than the raw AC (60–85%). - Abstract: This paper highlights the effect of iron impregnation and surface oxidation on the physicochemical characteristics of iron impregnated carbon materials. These materials were characterized by various techniques like surface area, pore size distribution, SEM/EDX, CHN, XRD, FTIR, TG/DT, VSM and XPS analyses. The increase in the surface functionalities and pores diameter (3.51–5.49 nm) of the iron-impregnated carbon materials was observed with the increase in iron contents and surface oxidation. The saturated magnetization values (0.029–0.034 emu/g) for the iron-impregnated carbon materials reflected the magnetic tendency due to the development of small size iron oxides on their surfaces. The XPS spectra revealed the existence of different oxidation states of the corresponding metals on the iron impregnated carbon materials. The percentage removal of model dyes (Methylene Blue and Methyl Orange) by iron-impregnated carbon materials was enhanced (>90%) with the increase in iron contents and pores diameters.


    Directory of Open Access Journals (Sweden)



    Full Text Available Biogas is one type of renewable energy which can be burnt to produce heat and electricity. However, it cannot be burnt directly due to the presence of hydrogen sulfide (H2S which is highly corrosive to gas engine. In this study, coconut shell activated carbon (CSAC was applied as a porous adsorbent for H2S removal. The effect of amount of activated carbon and flow rate of gas stream toward adsorption capacity were investigated. Then, the activated carbons were impregnated by three types of alkaline (NaOH, KOH and K2CO3 with various ratios. The effects of various types of alkaline and their impregnation ratio towards adsorption capacity were analysed. In addition, H2S influent concentration and the reaction temperature on H2S adsorption were also investigated. The result indicated that adsorption capacity increases with the amount of activated carbon and decreases with flow rate of gas stream. Alkaline impregnated activated carbons had better performance than unimpregnated activated carbon. Among all impregnated activated carbons, activated carbon impregnated by K2CO3 with ratio 2.0 gave the highest adsorption capacity. Its adsorption capacity was 25 times higher than unimpregnated activated carbon. The result also indicated that the adsorption capacity of impregnated activated carbon decreased with the increment of H2S influent concentration. Optimum temperature for H2S adsorption was found to be 50˚C. In this study, the adsorption of H2S on K2CO3 impregnated activated carbon was fitted to the Langmuir isotherm. The fresh and spent K2CO3 impregnated activated carbon were characterized to study the adsorption process.

  10. Performance of Conformable Phenolic Impregnated Carbon Ablator in Aerothermal Environments (United States)

    Thornton, Jeremy; Fan, Wendy; Stackpoole, Mairead; Kao, David; Skokova, Kristina; Chavez-Garcia, Jose


    Conformable Phenolic Impregnated Carbon Ablator, a cousin of Phenolic Impregnated Carbon Ablator (PICA), was developed at NASA Ames Research Center as a lightweight thermal protection system under the Fundamental Aeronautics Program. PICA is made using a brittle carbon substrate, which has a very low strain to failure. Conformable PICA is made using a flexible carbon substrate, a felt in this case. The flexible felt significantly increases the strain to failure of the ablator. PICA is limited by its thermal mechanical properties. Future NASA missions will require heatshields that are more fracture resistant than PICA and, as a result, NASA Ames is working to improve PICA's performance by developing conformable PICA to meet these needs. Research efforts include tailoring the chemistry of conformable PICA with varying amounts of additives to enhance mechanical properties and testing them in aerothermal environments. This poster shows the performance of conformable PICA variants in arc jets tests. Some mechanical and thermal properties will also be presented.

  11. Cyanate Ester and Phthalonitrile Impregnated Carbon Ablative TPS (United States)

    Boghozian, Tane; Stackpoole, Margaret M.; Gasch, Matt


    Phenolic resin has extensive heritage as a TPS (Thermal Protection Systems) material, however, alternative resin systems such as Cyanate Ester and Phthalonitrile may offer improved performance compared to state-of-the-art phenolic resin. These alternative resin systems may have higher char yield, higher char strength, lower thermal conductivity and improved mechanical properties. In current work at NASA Ames alternative resin systems were uniformly infused into fibrous substrates and preliminary properties characterized. The density of the cyanate ester infused in fibrous substrate ranged from 0.25-0.3 grams per cubic centimeter compared to PICA (Phenolic resin impregnated carbon ablative) having a density of approximately 0.25 grams per cubic centimeter. The density of Phthalonitrile varies from 0.22-0.25 grams per cubic centimeter. Initial formulations of these new resin systems were recently tested at the LARC HyMETs (Hypersonic Materials Environmental Test System) facility to evaluate their performance and data such as back face temperature, char yield, and recession are compared to PICA. Cyanate Ester and Phthalonitrile impregnated carbon ablative samples showed comparable performance to phenolic resin impregnated carbon ablative samples.

  12. Research on the melt impregnation of continuous carbon fiber reinforced nylon 66 composites (United States)

    Jia, M. Y.; Li, C. X.; Xue, P.; Chen, K.; Chen, T. H.


    Impregnation mold of continuous carbon fiber reinforced thermoplastic composites was designed and built in the article. Based on the theory of fluid mechanics and Darcy's law, a model of the melt impregnation was also established. The influences of fiber bundle width and impregnation pins’ diameter on the impregnation degree were studied by numerical simulation. Continuous carbon fiber reinforced nylon 66 composites were prepared. The effects of coated angle and impregnation mold temperature on the mechanical properties of the composites were also described.The agreement between the experimental data and prediction by the model was found to be satisfactory.

  13. Pressure Venting Tests of Phenolic Impregnated Carbon Ablator (PICA) (United States)

    Blosser, Max L.; Knutson, Jeffrey R.


    A series of tests was devised to investigate the pressure venting behavior of one of the candidate ablators for the Orion capsule heat shield. Three different specimens of phenolic impregnated carbon ablator (PICA) were instrumented with internal pressure taps and subjected to rapid pressure changes from near vacuum to one atmosphere and simulated Orion ascent pressure histories. The specimens vented rapidly to ambient pressure and sustained no detectable damage during testing. Peak pressure differences through the thickness of a 3-inch-thick specimen were less than 1 psi during a simulated ascent pressure history.

  14. Phenolic Impregnated Carbon Ablator (PICA) Gap Filler for Heat Shield Assemblies Project (United States)

    National Aeronautics and Space Administration — During this program, Fiber Materials, Inc. (FMI) will develop practical methods for preparing Phenolic Impregnated Carbon Ablator (PICA) materials for joining...

  15. Phenolic Impregnated Carbon Ablator (PICA) Gap Filler for Heat Shield Assemblies Project (United States)

    National Aeronautics and Space Administration — During this program Fiber Materials, Inc. (FMIREG) will develop practical methods for preparing Phenolic Impregnated Carbon Ablator (PICA) materials for joining...

  16. High performance asymmetric supercapacitor based on molybdenum disulphide/graphene foam and activated carbon from expanded graphite. (United States)

    Masikhwa, Tshifhiwa M; Madito, Moshawe J; Bello, Abdulhakeem; Dangbegnon, Julien K; Manyala, Ncholu


    Molybdenum disulphide which has a graphene-like single layer structure has excellent mechanical and electrical properties and unique morphology, which might be used with graphene foam as composite in supercapacitor applications. In this work, Molybdenum disulphide (MoS2)/graphene foam (GF) composites with different graphene foam loading were synthesized by the hydrothermal process to improve on specific capacitance of the composites. Asymmetric supercapacitor device was fabricated using the best performing MoS2/GF composite and activated carbon derived from expanded graphite (AEG) as positive and negative electrodes, respectively, in 6M KOH electrolyte. The asymmetric MoS2/GF//AEG device exhibited a maximum specific capacitance of 59Fg-1 at a current density of 1Ag-1 with maximum energy and power densities of 16Whkg-1 and 758Wkg-1, respectively. The supercapacitor also exhibited a good cyclic stability with 95% capacitance retention over 2000 constant charge-discharge cycles. The results obtained demonstrate the potential of MoS2/GF//AEG as a promising material for electrochemical energy storage application. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Antibacterial Carbon Nanotubes by Impregnation with Copper Nanostructures (United States)

    Palza, Humberto; Saldias, Natalia; Arriagada, Paulo; Palma, Patricia; Sanchez, Jorge


    The addition of metal-based nanoparticles on carbon nanotubes (CNT) is a relevant method producing multifunctional materials. In this context, CNT were dispersed in an ethanol/water solution containing copper acetate for their impregnation with different copper nanostructures by either a non-thermal or a thermal post-synthesis treatment. Our simple method is based on pure CNT in an air atmosphere without any other reagents. Particles without thermal treatment were present as a well-dispersed layered copper hydroxide acetate nanostructures on CNT, as confirmed by scanning and transmission (TEM) electron microscopies, and showing a characteristic x-ray diffraction peak at 6.6°. On the other hand, by thermal post-synthesis treatment at 300°C, these layered nanostructures became Cu2O nanoparticles of around 20 nm supported on CNT, as confirmed by TEM images and x-ray diffraction peaks. These copper nanostructures present on the CNT surface rendered antibacterial behavior to the resulting hybrid materials against both Staphylococcus aureus and Escherichia coli. These findings present for the first time a simple method for producing antibacterial CNT by direct impregnation of copper nanostructures.

  18. Investigation of Performance Envelope for Phenolic Impregnated Carbon Ablator (PICA) (United States)

    Agrawal, Parul; Prabhu, Dinesh; Milos, Frank S.; Stackpoole, Mairead


    The present work provides the results of a short exploratory study on the performance of Phenolic Impregnated Carbon Ablator, or PICA, at high heat flux and pressure in an arcjet facility at NASA Ames Research Center. The primary objective of the study was to explore the thermal response of PICA at cold-wall heat fluxes well in excess of 1500 W/cm (exp 2). Based on the results of a series of flow simulations, multiple PICA samples were tested at an estimated cold wall heat flux and stagnation pressure of 1800 W/cm (exp 2) and 130 kPa, respectively. All samples survived the test, and no failure was observed either during or after the exposure. The results indicate that PICA has a potential to perform well at environments with significantly higher heat flux and pressure than it has currently been flown.

  19. Impregnation of Ibuprofen into Polycaprolactone using supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Yoganathan, Roshan; Mammucari, Raffaella; Foster, Neil R, E-mail: [Supercritical Fluids Research Group, School of Chemical Sciences and Engineering, University of New South Wales, NSW 2052 (Australia)


    Polycaprolactone (PCL) is a Food and Drug Administration (FDA) approved biodegradable polyester used in tissue engineering applications. Ibuprofen is an anti-inflammatory drug which has good solubility in supercritical CO{sub 2} (SCCO{sub 2}). The solubility of CO{sub 2} in PCL allows for the impregnation of CO{sub 2}-soluble therapeutic agents into the polymer via a supercritical fluid (SCF) process. Polymers impregnated with bio-active compounds are highly desired for medical implants and controlled drug delivery. In this study, the use of CO{sub 2} to impregnate PCL with ibuprofen was investigated. The effect of operating conditions on the impregnation of ibuprofen into PCL was investigated over two pressure and two temperature levels, 150bar and 200bar, 35{sup 0}C and 40 {sup 0}C, respectively. Polycaprolactone with drug-loadings as high as 27% w/w were obtained. Impregnated samples exhibited controlled drug release profiles over several days.

  20. Synthesis of carbon nanofibers on impregnated powdered activated carbon as cheap substrate

    Directory of Open Access Journals (Sweden)

    A.A. Mamun


    Full Text Available The catalysis and characterization of carbon nanofibers (CNFs composite are reported in this work. Carbon nanofibers were produced on oil palm shell powdered activated carbon (PAC, which was impregnated with nickel. Chemical Vapor Deposition (CVD of C2H2 was used in the presence of hydrogen at ∼650 °C. The flow rates of carbon source and hydrogen were fixed. The CNFs formed directly on the surface of the impregnated PAC. Variable weight percentages (1%, 3%, 5%, 7% and 9% of the catalyst salt (Ni+2 were used for the impregnation. However, the best catalysis was observed on the substrate with 3% Ni+2. The product displayed a relatively high surface area, essentially constituted by the external surface. New functional groups also appeared compared to those in the PAC. Field Emission Scanning Microscopy (FESEM, Transmission Electron Microscopy (TEM, Fourier Transform Infrared (FTIR, BET surface area analysis and energy dispersive X-ray (EDX were used for the characterization of the new carbon nano product, which was produced through a clean novel process.

  1. Carbonization of heavy metal impregnated sewage sludge oriented towards potential co-disposal

    Energy Technology Data Exchange (ETDEWEB)

    Dou, Xiaomin [Thermal & Environmental Engineering Institute, Tongji University, Shanghai 201804 (China); Chen, Dezhen, E-mail: [Thermal & Environmental Engineering Institute, Tongji University, Shanghai 201804 (China); Hu, Yuyan; Feng, Yuheng [Thermal & Environmental Engineering Institute, Tongji University, Shanghai 201804 (China); Dai, Xiaohu [National Engineering Research Centre for Urban Pollution Control, Tongji University, Shanghai 200092 (China); College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)


    Highlights: • The carbonization of SS with externally impregnated heavy metals was investigated. • Externally impregnated heavy metals can be immobilized in the SSC. • Higher carbonization temperature help produce non-hazardous SSC. • Incineration FA can be kneaded into SS for co-disposal through co-carbonization. - Abstract: Sewage sludge (SS) is adopted as a stabilizer to immobilize externally impregnated heavy metals through carbonization oriented towards the co-disposal of SS and some hazardous wastes. Firstly Cu and Pb were impregnated into SS to ascertain the impregnating capacity and leaching behaviours of heavy metals in the resulting sewage sludge char (SSC). Meanwhile, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed to detect the heavy metal phase in the SSC. The results showed that within 400–800 °C and an impregnating concentration ≨0.5 wt%, more than 90% of the externally impregnated Cu and Pb were remained in the SSC and immobilized. And higher temperatures helped produce non-hazardous SSC. In addition, SEM and XRD analyses revealed that externally impregnated heavy metals could be converted into stable forms and evenly distributed throughout the SSC. In the second step municipal solid waste incineration fly ash (FA) was kneaded into SS and subjected to carbonization; it has been proved that the heavy metals in FA can be well immobilized in the resulting char when FA: SS mass ratio is 1:5. Those results show that sewage sludge can be co-carbonized with wastes contaminated with heavy metals to achieve co-disposal.

  2. Preparation of sulfurized powdered activated carbon from waste tires using an innovative compositive impregnation process. (United States)

    Yuan, Chung-Shin; Lin, Hsun-Yu; Wu, Chun-Hsin; Liu, Ming-Han; Hung, Chung-Hsuang


    The objective of this study is to develop an innovative compositive impregnation process for preparing sulfurized powdered activated carbon (PAC) from waste tires. An experimental apparatus, including a pyrolysis and activation system and a sulfur (S) impregnation system, was designed and applied to produce sulfurized PAC with a high specific surface area. Experimental tests involved the pyrolysis, activation, and sulfurization of waste tires. Waste-tire-derived PAC (WPAC) was initially produced in the pyrolysis and activation system. Experimental results indicated that the Brunauer-Emmett-Teller (BET) surface area of WPAC increased, and the average pore radius of WPAC decreased, as water feed rate and activation time increased. In this study, a conventional direct impregnation process was used to prepare the sulfurized PAC by impregnating WPAC with sodium sulfide (Na2S) solution. Furthermore, an innovative compositive impregnation process was developed and then compared with the conventional direct impregnation process. Experimental results showed that the compositive impregnation process produced the sulfurized WPAC with high BET surface area and a high S content. A maximum BET surface area of 886 m2/g and the S content of 2.61% by mass were obtained at 900 degrees C and at the S feed ratio of 2160 mg Na2S/g C. However, the direct impregnation process led to a BET surface area of sulfurized WPAC that decreased significantly as the S content increased.

  3. Carbon molecular sieves from carbon cloth: Influence of the chemical impregnant on gas separation properties (United States)

    Rodríguez-Blanco, G.; Giraldo, L.; Moreno-Piraján, J. C.


    Carbon materials with molecular sieve properties (CMS) were prepared by pyrolysis of cotton fabrics by chemical activation procedures. To evaluate the changes in the chemical and textural properties, the impregnants AlCl 3, ZnCl 2 and H 3PO 4 were used at 1123 K. The materials were characterized using adsorption of nitrogen and carbon dioxide, TPD, and immersion calorimetry in C 6H 6. Adsorption kinetics of O 2, N 2, CO 2, CH 4, C 3H 8 and C 3H 6 were measured in all the prepared materials to determine their behaviour as molecular sieves. The results confirm that the chemical used as impregnant has a significant effect on the resulting CMS separation properties. All materials exhibit microporosity and low oxygen surface group contents; however, the sample impregnated with zinc chloride, with an immersion enthalpy value of 66.4 J g -1 in benzene, exhibits the best performance in the separation of CH 4-CO 2 and C 3H 8-C 3H 6 at 273 K.

  4. Preparation of iron-impregnated granular activated carbon for arsenic removal from drinking water. (United States)

    Chang, Qigang; Lin, Wei; Ying, Wei-chi


    Granular activated carbon (GAC) was impregnated with iron through a new multi-step procedure using ferrous chloride as the precursor for removing arsenic from drinking water. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis demonstrated that the impregnated iron was distributed evenly on the internal surface of the GAC. Impregnated iron formed nano-size particles, and existed in both crystalline (akaganeite) and amorphous iron forms. Iron-impregnated GACs (Fe-GACs) were treated with sodium hydroxide to stabilize iron in GAC and impregnated iron was found very stable at the common pH range in water treatments. Synthetic arsenate-contaminated drinking water was used in isotherm tests to evaluate arsenic adsorption capacities and iron use efficiencies of Fe-GACs with iron contents ranging from 1.64% to 12.13% (by weight). Nonlinear regression was used to obtain unbiased estimates of Langmuir model parameters. The arsenic adsorption capacity of Fe-GAC increased significantly with impregnated iron up to 4.22% and then decreased with more impregnated iron. Fe-GACs synthesized in this study exhibited higher affinity for arsenate as compared with references in literature and shows great potential for real implementations. Copyright © 2010 Elsevier B.V. All rights reserved.

  5. Thermal Effect on the phosphoric Acid Impregnated Activated Carbon Fiber and Adsorption Properties Toward Isoprene

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Taek Sung; Lee, Jin Hyok; Kang, Kyung suk [Department of Chemical Engineering, College of Engineering, Chungnam National University, Taejon (Korea); Kim, Kwang Young [Ace Lab. Co. Ltd. Taejon (Korea); Rhee, Moon Soo [Korea Ginseng and Tobacoo Research Institute, Taejon (Korea)


    To introduce chemisorption property and improve adsorption capacities for isoprene, ACF (Activated Carbon Fiber) was impregnated by phosphoric acid. As the impregnated ACF was dried by programmed temperature from 300 degree C to 500 degree C, degree of impregnation, surface area, thermal stability and adsorption properties for isoprene were observed. The degree of impregnation of the ACF, dried at the 400 degree C, was 12.7 w/w% and surface area was 1148 m{sup 2}/g. Over the temperature range of 450 degree C to 700 degree C, there was one-step thermal degradation by the thermal decomposition of phosphonyl group. The adsorption rate of phosphoric acid on the impregnated ACF, which was dried at 400 degree C, was the fastest. The breakthrough time of ACF that was dried at 400 degree C was 18 min., and its adsorption capacity improved roughly 7.2 times in comparison to the pure ACF. In addition, it was observed the adsorption properties persisted even after the regeneration. The adsorption efficiency of regenerated ACF was 66 percent compared to the unused impregnated ACF. 21 refs., 7 figs., 3 tabs.

  6. Removal of bromide from surface waters using silver impregnated activated carbon. (United States)

    Chen, Chen; Apul, Onur Guven; Karanfil, Tanju


    The main objectives of this study were to develop an understanding of silver impregnated activated carbon (SIAC) preparation for enhanced bromide (Br - ) removal from water, and to investigate the impact of aqueous background composition on the Br - removal. Several SIACs were produced using various combinations of oxidation and silver impregnation procedures and powdered activated carbons (ACs). Regardless of the preparation procedure, SIACs showed significantly Br - uptakes than the virgin ACs. The Br - removal efficiency was affected by (i) the background water composition (e.g. Cl - and NOM competition reduced the Br - uptake), (ii) silver impregnation process (e.g. silver content, pre-oxidation of virgin AC; silver impregnation largely increased the Br - removal, and the pre-oxidation of AC prior to silver impregnation was found to be important), and (iii) AC characteristics (e.g. surface area, oxygen content; SIACs with higher silver contents and larger surface areas exhibited higher degrees of Br - removal). The Br - removal by SIAC reduced the formation of brominated THMs. Jar test results showed that coagulation did not have an impact on Br - removal by SIAC. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Enhanced Adsorption of Selenium Ions from Aqueous Solution Using Iron Oxide Impregnated Carbon Nanotubes. (United States)

    Bakather, Omer Y; Kayvani Fard, Ahmad; Ihsanullah; Khraisheh, Majeda; Nasser, Mustafa S; Atieh, Muataz Ali


    The aim of this research was to investigate the potential of raw and iron oxide impregnated carbon nanotubes (CNTs) as adsorbents for the removal of selenium (Se) ions from wastewater. The original and modified CNTs with different loadings of Fe2O3 nanoparticles were characterized using high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffractometer (XRD), Brunauer, Emmett, and Teller (BET) surface area analyzer, thermogravimetric analysis (TGA), zeta potential, and energy dispersive X-ray spectroscopy (EDS). The adsorption parameters of the selenium ions from water using raw CNTs and iron oxide impregnated carbon nanotubes (CNT-Fe2O3) were optimized. Total removal of 1 ppm Se ions from water was achieved when 25 mg of CNTs impregnated with 20 wt.% of iron oxide nanoparticles is used. Freundlich and Langmuir isotherm models were used to study the nature of the adsorption process. Pseudo-first and pseudo-second-order models were employed to study the kinetics of selenium ions adsorption onto the surface of iron oxide impregnated CNTs. Maximum adsorption capacity of the Fe2O3 impregnated CNTs, predicted by Langmuir isotherm model, was found to be 111 mg/g. This new finding might revolutionize the adsorption treatment process and application by introducing a new type of nanoadsorbent that has super adsorption capacity towards Se ions.

  8. Effect of tar impregnation on carbon monoxide disintegration resistance in refractory lining of torpedo ladle

    Energy Technology Data Exchange (ETDEWEB)

    Chien, Y.T.; Ko, Y.C.


    Investigates whether the Ludwig-Sorret effect could be used to cope with the lining disintegration caused by the deposition of carbon from carbon monoxide in torpedo ladles by impregnating with tar the aluminosilicate refractory brick which are not immune to carbon monoxide attack. Explains, on the basis of Ludwig-Sorret effect, that fluids diffuse from a region of higher temperature to that of lower temperature under the driving force of a temperature gradient; tar impregnated in torpedo ladle lining will flow toward the cold end during preheating and in service. Finds that the nondisintegration portion of the specimen contained neither carbon nor iron oxide-like substance. X-ray diffraction proved that an ironoxide-like substance, collected from the sites where carbon deposited, contained hematite and magnetite. Microscopic examination indicated that most residual carbon was found in the fine pores in the matrix. Concludes that it seems unlikely that tar impregnation for refractory brick that are not immune to carbon monoxide disintegration can significantly improve the disintegration resistance in torpedo ladles in service.

  9. Dielectric microwave absorbing material processed by impregnation of carbon fiber fabric with polyaniline

    Directory of Open Access Journals (Sweden)

    Luiza de Castro Folgueras


    Full Text Available It is a known fact that the adequate combination of components and experimental conditions may produce materials with specific requirements. This study presents the effect of carbon fiber fabric impregnation with polyaniline conducting polymer aiming at the radar absorbing material processing. The experiments consider the sample preparation with one and two impregnations. The prepared samples were evaluated by reflectivity measurements, in the frequency range of 8-12 GHz and scanning electron microscopy analyses. The correlation of the results shows that the quantity of impregnated material influences the performance of the processed microwave absorber. This study shows that the proposed experimental route provides flexible absorbers with absorption values of the incident radiation close to 87%.

  10. Influence of both the composition of impregnation solution and impregnation method on copper(II, chromium(VI and silver(I deposition on activated carbon

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    Ivanović Slavica


    Full Text Available The composition of a solution for impregnating activated carbon (AC for use in a gas filter was investigated. The solution components were tetraaminocop-per(II complex, chromium(VI, silver(l and carbonate ions. Two methods of impregnation were investigated: ion adsorption from aqueous solution in excess and the incipient wetness method. Copper, chromium and silver con-tents on AC Were determined by atomic absorption spectrometry. The largest copper contents (4.38 and 5.00 % (w/w for two AC samples were achieved at: c([Cu(NH34]2+ = 1.0 mol/L; M(Cu i M(Cr = 3.75: 1; M(Cu i M(Ag = 62: 1 and M(Cu: M(CO3 = 2: 1, using two fold impregnation by the incipient wetness method with 2.4 mL of solution per 3 g AC. The contents of chromium and silver on the same AC samples Were 1.06 and 0.0098 % for the first and 1.14 and 0.009 % for the second AC. A larger Cr content (1.57 % was achieved from an impregnation solution in excess (c([Cu(NH34]2+ = 1.25 mol/L; M(Cu i M(Cr = 3: 1; without Ag. The largest Ag content (0.17 % was obtained using two fold impregnation by the incipient wetness method (c([Cu(NH34]2+ = 0.8 mol/L; M(Cu: M(Cr = 3.75: 1<; M(Cu i M(Ag ( 80: 1 and M(Cu i M(CO3 = 1 i 1.32. Larger metal contents were obtained using two fold impregnation by the incipient wetness method. Further work is needed on the determination of the influence of carbonate ions both on the solution stability and metal deposition on AC.

  11. Silica-coated multi-walled carbon nanotubes impregnated with polyethyleneimine for carbon dioxide capture under the flue gas condition (United States)

    Lee, Min-Sang; Park, Soo-Jin


    In this study, silica-coated multi-walled carbon nanotubes impregnated with polyethyleneimine (PEI) were prepared via a two-step process: (i) hydrolysis of tetraethylorthosilicate onto multi-walled carbon nanotubes, and (ii) impregnation of PEI. The adsorption properties of CO2 were investigated using CO2 adsorption-desorption isotherms at 298 K and thermogravimetric analysis under the flue gas condition (15% CO2/85% N2). The results obtained in this study indicate that CO2 adsorption increases after impregnation of PEI. The increase in CO2 capture was attributed to the affinity between CO2 and the amine groups. CO2 adsorption-desorption experiments, which were repeated five times, also showed that the prepared adsorbents have excellent regeneration properties.

  12. Silica-coated multi-walled carbon nanotubes impregnated with polyethyleneimine for carbon dioxide capture under the flue gas condition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Min-Sang; Park, Soo-Jin, E-mail:


    In this study, silica-coated multi-walled carbon nanotubes impregnated with polyethyleneimine (PEI) were prepared via a two-step process: (i) hydrolysis of tetraethylorthosilicate onto multi-walled carbon nanotubes, and (ii) impregnation of PEI. The adsorption properties of CO{sub 2} were investigated using CO{sub 2} adsorption–desorption isotherms at 298 K and thermogravimetric analysis under the flue gas condition (15% CO{sub 2}/85% N{sub 2}). The results obtained in this study indicate that CO{sub 2} adsorption increases after impregnation of PEI. The increase in CO{sub 2} capture was attributed to the affinity between CO{sub 2} and the amine groups. CO{sub 2} adsorption–desorption experiments, which were repeated five times, also showed that the prepared adsorbents have excellent regeneration properties. - Graphical abstract: Fabrication and CO{sub 2} adsorption process of the S-MWCNTs impregnated with PEI. - Highlights: • Silica coated-MWCNT impregnated with PEI was synthesized. • Amine groups of PEI gave CO{sub 2} affinity sites on MWCNT surfaces. • The S-MWCNT/PEI(50) exhibited the highest CO{sub 2} adsorption capacity.

  13. The investigation of copper-based impregnated activated carbons prepared from water-soluble materials for broad spectrum respirator applications. (United States)

    Smith, J W H; Westreich, P; Abdellatif, H; Filbee-Dexter, P; Smith, A J; Wood, T E; Croll, L M; Reynolds, J H; Dahn, J R


    The preparation of impregnated activated carbons (IACs) from aqueous, copper-containing solutions for broad spectrum gas filtration applications is studied here. Several samples were studied to determine the effect that impregnant loading, impregnant distribution and impregnant recipe had on the overall performance. Dynamic flow testing was used to determine the gas filtration capacity of the IAC samples versus a variety of challenge gases. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) were used to characterize the impregnant distribution on the carbon as a function of impregnant loading. Oven tests were performed to determine the thermal stability of the IAC samples exposed to elevated temperatures. The role impregnant distribution plays in gas filtration capacity and the overall performance of the IAC samples is discussed. The IAC samples prepared in this work were found to have gas filtration capacities as good as or better than broad spectrum respirator carbon samples prepared from the patent literature. IACs impregnated with an aqueous 2.4 M Cu(NO(3))(2)/0.04 M H(3)PO(4).12MoO(3)/4M HNO(3) solution that were heated to 200 degrees C under argon were found to have the best overall performance of the samples studied in this work. Copyright 2010 Elsevier B.V. All rights reserved.

  14. Kinetic and equilibrium studies on fluoride removal by zirconium (IV: Impregnated groundnut shell carbon

    Directory of Open Access Journals (Sweden)

    Alagumuthu G.


    Full Text Available The carbonized ground nut shell (GNSC was impregnated with zirconium oxy chloride, and tested to determine its capacity and kinetics for fluoride adsorption from aqueous solutions. The analysis of the isotherm equilibrium data using the Langmuir, Freundlich and Redlich-Peterson equations by linear methods showed that the data fitted better with Freundlich model than the other two. Thermodynamic studies revealed that the spontaneous nature of fluoride adsorption with increase of entropy and an endothermic process. The kinetic data obtained for fluoride adsorption on zirconium impregnated ground nut shell carbon (ZIGNSC obeyed the pseudo-second order equation. X-ray diffraction (XRD studies confirmed the deposition of fluoride on material and Fourier transform infrared (FTIR studies also showed the involvement of adsorbate on the adsorbent surface in the adsorption interaction. The ZIGNSC provides a cost effective material to the defluoridation problem in the developing countries by its great potential application in the fluoride removal from water.

  15. Bioregeneration of spent mercury bearing sulfur-impregnated activated carbon adsorbent. (United States)

    Chen, Shen-Yi; Hsi, Hsing-Cheng; Shih, Min-Yu


    Among various adsorbents studied, sulfur-impregnated activated carbon is one of the most promising adsorbents for mercury removal from flue gas. However, a large amount of spent activated carbons containing high content of mercury are generated after adsorption. To make the adsorption a more viable option, the regeneration and reuse of the spent activated carbon should be considered. The purpose of this study is to develop a novel technique for bioregeneration of sulfur-impregnated activated carbons after adsorption of mercury from flue gases by sulfur-oxidizing bacteria. The optimal operating parameters for this bioregeneration process were studied using central composite design (CCD) and response surface methodology (RSM). Results showed that the sulfur oxidation rate was increased with increasing activated carbon dosage. Furthermore, the increase of inoculum size only caused a slight increase of sulfur oxidation rate in the bioregeneration. The maximum mercury removal efficiency of more than 50% was obtained at 10% (w/v) activated carbon dosage and 20% (v/v) inoculum size. After the bioregeneration process, Brunauer-Emmett-Teller (BET) surface area and micropore volume of spent activated carbon increased due to the bio-oxidation of mercury bearing sulfur on the surface of activated carbons.

  16. Production of activated carbons from pyrolysis of waste tires impregnated with potassium hydroxide. (United States)

    Teng, H; Lin, Y C; Hsu, L Y


    Activated carbons were produced from waste tires using a chemical activation method. The carbon production process consisted of potassium hydroxide (KOH) impregnation followed by pyrolysis in N2 at 600-900 degrees C for 0-2 hr. The activation method can produce carbons with a surface area (SA) and total pore volume as high as 470 m2/g and 0.57 cm3/g, respectively. The influence of different parameters during chemical activation, such as pyrolysis temperature, holding time, and KOH/tire ratio, on the carbon yield and the surface characteristics was explored, and the optimum preparation conditions were recommended. The pore volume of the resulting carbons generally increases with the extent of carbon gasified by KOH and its derivatives, whereas the SA increases with degree of gasification to reach a maximum value, and then decreases upon further gasification.

  17. Impregnation Nickel on Mesoporous ZSM-5 Templated Carbons as a Candidate Material for Hydrogen Storage

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    Ratna Ediati


    Full Text Available A series of carbon with ZSM-5 mesoporous (ZMC and Ni/ZMC ZSM-5 templates were synthesized and gravimetrically known its adsorption capacity to H2 gases. ZMC carbon was synthesized using a hard template method at a carbonation temperature of 900 oC with sucrose as a source of carbon. A mesoporous ZSM-5 template was synthesized by using a hydrothermal method at an aging and crystallization temperature of respectively 60oC and 150oC for as long as 24 hours. The characterized result of ZMC carbon using XRD powder has shown a diffracted pattern of amorphous carbon. Impregnating Ni with ZMC carbon each resulted in 5%, 15% and 25% of weight, which in turn also resulted in a diffractogram pattern of Ni/ZMC-5, Ni/ZMC-15, and Ni/ZMC-25, where each patterns were uniform and had no additional peaks. The results of SEM-EDAX showed that Ni had been successfully impregnated on the surface of ZMC carbon with a random morphology surface of ZMC carbon. The isothermal results of adsorption – desorption of N2 showed that the larger the Ni loading on the supporting ZMC carbon, the smaller the surface area of the ZMC specific carbon. The distribution of the pore size that was counted by using the BJH method, which was applied to all the samples, was as big as 3,8 nm. The adsorption capacity of H2 was measured by using the gravimetry method at ambient temperature for Ni/ZMC-5, Ni/ZMC-15, and Ni/ZMC-25, which each gave a weight percentage of 0,331%; 0,663% and 0,649% respectively, whilst the ZMC carbon has a weight of 2,18%.

  18. Novel Aluminum Oxide-Impregnated Carbon Nanotube Membrane for the Removal of Cadmium from Aqueous Solution

    Directory of Open Access Journals (Sweden)



    Full Text Available An aluminum oxide-impregnated carbon nanotube (CNT-Al2O3 membrane was developed via a novel approach and used in the removal of toxic metal cadmium ions, Cd(II. The membrane did not require any binder to hold the carbon nanotubes (CNTs together. Instead, the Al2O3 particles impregnated on the surface of the CNTs were sintered together during heating at 1400 °C. Impregnated CNTs were characterized using XRD, while the CNT-Al2O3 membrane was characterized using scanning electron microscopy (SEM. Water flux, contact angle, and porosity measurements were performed on the membrane prior to the Cd(II ion removal experiment, which was conducted in a specially devised continuous filtration system. The results demonstrated the extreme hydrophilic behavior of the developed membrane, which yielded a high water flux through the membrane. The filtration system removed 84% of the Cd(II ions at pH 7 using CNT membrane with 10% Al2O3 loading. A maximum adsorption capacity of 54 mg/g was predicted by the Langmuir isotherm model for the CNT membrane with 10% Al2O3 loading. This high adsorption capacity indicated that adsorption was the main mechanism involved in the removal of Cd(II ions.

  19. Vapor mercury uptake with sulphur impregnated active carbons derived using sulphur dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Tong, S.; Methta, H.; Ahmed, I.; Morris, E.; Fuentes de Maria, L. [Wuhan Univ. of Science and Technology, Wuhan, Hubei (China). Dept. of Chemical Engineering; Jia, C.Q. [Toronto Univ., ON (Canada). Dept. of Chemical Engineering and Applied Chemistry


    Active carbon adsorption is the primary technology used for removal of vapour mercury from flue gases in coal-fired power plants, municipal solid waste combustors, and other sources. It can be carried out using two different processes, notably injection of powder active carbon into flue gas streams upstream of the particulate collection devices, and filtration with a granular active carbon fixed bed downstream of the flue gas desulphurization units and/or particulate collectors. This paper presented an investigation of vapour mercury uptake performance of laboratory-made sulphur impregnated active carbons (SIACs) using a fixed bed reactor in a temperature range of 25 to 200 degrees Celsius. The materials and methods as well as the properties of activated carbons studied were presented. The experimental set-up was also described. The paper discussed the effects of initial concentration, the flow rate, the loading amount of SIACs, temperature, and the sulphur impregnation on the mercury uptake performance. The study showed that SIACs produced with sulphur dioxide exhibited a more complicated behaviour when temperature was varied, implying a mixed adsorption mechanism. 10 refs., 3 tabs., 8 figs.


    Directory of Open Access Journals (Sweden)

    Isil Isik-Gulsac

    Full Text Available Abstract The effects of relative humidity (RH, carbon dioxide (CO2, methane (CH4, oxygen (O2 presence and gas hourly space velocity (GHSV on H2S adsorption dynamics of KOH/CaO impregnated activated carbon are investigated in this study. X-ray diffraction (XRD, scanning electron microscopy with energy dispersive X-ray detector (SEM-EDX, thermogravimetric analysis (TGA, and Fourier Transform Infrared Spectroscopy (FTIR techniques are applied and nitrogen adsorption characteristics are determined for characterization. The presence of water, O2 and lower GHSV has beneficial effects on the activated carbon performance. CO2 decreases the adsorption capacity due to its acidic characteristics. Best adsorption capacity is obtained as 13 wt % in KOH/CaO impregnated activated carbon, in a CH4 (60%/CO2 (38%/O2 (2% gas atmosphere, at ambient temperature, RH 90 and 5000 h-1 GHSV. Sulphur species formation was verified with the help of SEM-EDX, XRD, TGA, FTIR and nitrogen adsorption analysis on the exhausted samples.

  1. Effect of impregnation pressure and time on the porosity, structure and properties of polyacrylonitrile-fiber based carbon composites (United States)

    Venugopalan, Ramani; Roy, Mainak; Thomas, Susy; Patra, A. K.; Sathiyamoorthy, D.; Tyagi, A. K.


    Carbon-carbon composites may find applications in critical parts of advanced nuclear reactors. A series of carbon-carbon composites were prepared using polyacrylonitrile (PAN) based carbon fibers. The materials were densified by impregnating two-dimensional (2D) preforms with liquid phenol formaldehyde resin at different pressures and for different periods of time and then carbonizing those by slowly heating at 1000 °C. Effects of the processing parameters on the structure of the composites were extensively studied. The study showed conclusively that open porosity decreased with increasing impregnation pressure, whereas impregnation time had lesser effect. Matrix-resin bonding also improved at higher pressure. d002 spacing decreased and ordering along c-axis increased with concomitant increase in sp2-carbon fraction at higher impregnation pressures. The fiber reinforced composites exhibited short range ordering of carbon atoms and satisfied structural conditions (d002 values) of amorphous carbon according to the turbostratic model for non-graphitic carbon materials. The composites had pellet-density of ˜85% of the theoretical value, low thermal expansion and negligible neutron-poisoning. They maintained structural integrity and retained disordered nature even on heat-treatment at ca. 1800 °C.

  2. O2 electrocatalysis in acid media on iron naphthalocyanine impregnations. Effect of nitric acid treatment on different carbon black supports

    NARCIS (Netherlands)

    Coowar, F.; Contamin, O.; Savy, M.; Scarbeck, G.; van den Ham, D.; Riga, J.; Verbist, J.J.


    O2 electrocatalysis on (2,3)FeNPc impregnations on different carbon blacks was investigated in H2SO4 medium. The effect of nitric acid treatment on the carbon black support is to enhance both the activity and stability of the catalyst. Moreover, as seen by XPS, the dissolution of iron is impeded by

  3. Application of activated carbon impregnated with metal oxides to the treatment of multi-contaminants. (United States)

    Yu, Mok-Ryun; Chang, Yoon-Young; Yang, Jae-Kyu


    In this study, as a novel technique for the simultaneous treatment of As(III) and phenol in a single column reactor, different ratios of manganese-impregnated activated carbon (Mn-AC) and iron-impregnated activated carbon (Fe-AC) were applied in a bench-scale column reactor. In this bench-scale test, the column system packed with both Mn-AC and Fe-AC (binary system) was identified as the best system due to the good oxidation efficiency of As(III) to As(V) by Mn-AC, which reasonably controlled the mobility of total arsenic through adsorption of As(V), along with efficient removal of phenol . When the pilot-scale column reactor, packed with equal amounts of Mn-AC and Fe-AC, was applied for the removal of As(III) and phenol, the oxidation of As(III) by 1 g of Mn-AC for up to 110 days and the removal of phenol by total 1 g of Mn-AC and Fe-AC for up to 100 days were 1.81 x 10(-4) g and 8.20 x 10(-4) g, respectively. Based on this work, Fe-AC and Mn-AC can be regarded as a promising filter material in the treatment of wastewater contaminated with organic compounds, such as phenol, and redox-sensitive ions, such as As(III).

  4. Dynamic Mechanical Properties of Aramid Fabrics Impregnated with Carbon Nanotube/Poly (Vinyl Butyral/Ethanol Solution

    Directory of Open Access Journals (Sweden)

    V. Obradović


    Full Text Available In this study six samples of polyurethane/p-aramid multiaxial fabric forms (Colon fabrics were coated with 10 wt.% poly (vinyl butyral (PVB/ethanol solution with the addition of multiwalled carbon nanotubes (MWCNT. The solution was impregnated on both sides of each of the fabrics. All composite samples consisted of four layers of the impregnated fabrics. The MWCNT/PVB content was 0, 0.1 and 1 wt.%. The three samples of the fabrics with different MWCNT/PVB content were coated with γ-aminopropyltriethoxysilane (AMEO silane/ethanol solution due to the surface modification. The mechanical properties of the prepared composite samples were studied by dynamic mechanical analysis (DMA. The 60% increase in storage modulus was achieved by addition of MWCNT and impregnation of aramid fabrics with AMEO silane. The pristine multiwalled carbon nanotubes (MWCNT were introduced in order to enhance additionally the mechanical properties of the materials for ballistic protection.

  5. Effects of sulfur impregnation temperature on the properties and mercury adsorption capacities of activated carbon fibers (ACFs) (United States)

    Hsi, H.-C.; Rood, M.J.; Rostam-Abadi, M.; Chen, S.; Chang, R.


    Laboratory studies were conducted to determine the role of sulfur functional groups and micropore surface area of carbon-based adsorbents on the adsorption of Hg0 from simulated coal combustion flue gases. In this study, raw activated carbon fibers that are microporous (ACF-20) were impregnated with elemental sulfur between 250 and 650 ??C. The resulting samples were saturated with respect to sulfur content. Total sulfur content of the sulfur impregnated ACF samples decreased with increasing impregnation temperatures from 250 and 500 ??C and then remained constant to 650 ??C. Results from sulfur K-edge X-ray absorption near-edge structure (S-XANES) spectroscopy showed that sulfur impregnated on the ACF samples was in both elemental and organic forms. As sulfur impregnation temperature increased, however, the relative amounts of elemental sulfur decreased with a concomitant increase in the amount of organic sulfur. Thermal analyses and mass spectrometry revealed that sulfur functional groups formed at higher impregnation temperatures were more thermally stable. In general, sulfur impregnation decreased surface area and increased equilibrium Hg0 adsorption capacity when compared to the raw ACF sample. The ACF sample treated with sulfur at 400 ??C had a surface area of only 94 m2/g compared to the raw ACF sample's surface area of 1971 m2/g, but at least 86% of this sample's surface area existed as micropores and it had the largest equilibrium Hg0adsorption capacities (2211-11343 ??g/g). Such a result indicates that 400 ??C is potentially an optimal sulfur impregnation temperature for this ACF. Sulfur impregnated on the ACF that was treated at 400 ??C was in both elemental and organic forms. Thermal analyses and CS2extraction tests suggested that elemental sulfur was the main form of sulfur affecting the Hg0 adsorption capacity. These findings indicate that both the presence of elemental sulfur on the adsorbent and a microporous structure are important properties for

  6. Resin-Impregnated Carbon Ablator: A New Ablative Material for Hyperbolic Entry Speeds (United States)

    Esper, Jaime; Lengowski, Michael


    Ablative materials are required to protect a space vehicle from the extreme temperatures encountered during the most demanding (hyperbolic) atmospheric entry velocities, either for probes launched toward other celestial bodies, or coming back to Earth from deep space missions. To that effect, the resin-impregnated carbon ablator (RICA) is a high-temperature carbon/phenolic ablative thermal protection system (TPS) material designed to use modern and commercially viable components in its manufacture. Heritage carbon/phenolic ablators intended for this use rely on materials that are no longer in production (i.e., Galileo, Pioneer Venus); hence the development of alternatives such as RICA is necessary for future NASA planetary entry and Earth re-entry missions. RICA s capabilities were initially measured in air for Earth re-entry applications, where it was exposed to a heat flux of 14 MW/sq m for 22 seconds. Methane tests were also carried out for potential application in Saturn s moon Titan, with a nominal heat flux of 1.4 MW/sq m for up to 478 seconds. Three slightly different material formulations were manufactured and subsequently tested at the Plasma Wind Tunnel of the University of Stuttgart in Germany (PWK1) in the summer and fall of 2010. The TPS integrity was well preserved in most cases, and results show great promise.

  7. Adsorption of Thiophenic Compounds from Model Diesel Fuel Using Copper and Nickel Impregnated Activated Carbons

    Directory of Open Access Journals (Sweden)

    Ramin Karimzadeh


    Full Text Available Adsorption of sulfur compoundsby porous materials is an effective way to produce cleaner diesel fuel.In this study, adsorption of refractory thiophenic sulfur compounds, i.e., benzothiophene (BT, dibenzothiophene (DBT, and 4,6-dimethyldibenzothiophene (4,6-DMDBT in single-solute systems from n-hexane solutions onto metal-impregnated activated carbons was investigated. A hydrogen-treated activated carbon fiber was selectively loaded with Ni, NiO, Cu, Cu2O, and CuO species to systematically assess the impact of each metal species on the adsorption of thiophenic compounds (TC. Metal-loaded adsorbents had the same total metal contents and similar microporosities, but contained different types of copper or nickel species. All metal-loaded adsorbents showed enhanced adsorption of tested TC. Cu2O- or NiO-loaded adsorbents exhibited the highest uptakes, due to more specific interactions between Cu+ or Ni2+ species and TC molecules. The theoretical monolyer coverage of TC on the exposed Cu+ sites was estimated and compared with that calculated from the experimental data. Results suggested catalytic conversion of TC molecules to other compounds on the Cu+ sites, followed by adsorption of reaction products onto the carbon surface or multilayer accumulation of TC molecules on the Cu+sites. TC adsorption uptake of the majority of adsorbents followed the order of: 4,6-DMDBT > DBT > BT due to higher intensity of specific and non-specific interactions of larger TC molecules with adsorbents.

  8. Capturing the Local Adsorption Structures of Carbon Dioxide in Polyamine-Impregnated Mesoporous Silica Adsorbents. (United States)

    Huang, Shing-Jong; Hung, Chin-Te; Zheng, Anmin; Lin, Jen-Shan; Yang, Chun-Fei; Chang, Yu-Chi; Deng, Feng; Liu, Shang-Bin


    Interactions between amines and carbon dioxide (CO2) are essential to amine-functionalized solid adsorbents for carbon capture, and an in-depth knowledge of these interactions is crucial to adsorbent design and fabrication as well as adsorption/desorption processes. The local structures of CO2 adsorbed on a tetraethylenepentamine-impregnated mesoporous silica SBA-15 were investigated by solid-state (13)C{(14)N} S-RESPDOR MAS NMR technique and theoretical DFT calculations. Two types of adsorption species, namely, secondary and tertiary carbamates as well as distant ammonium groups were identified together with their relative concentrations and relevant (14)N quadrupolar parameters. Moreover, a dipolar coupling of 716 Hz was derived, corresponding to a (13)C-(14)N internuclear distance of 1.45 Å. These experimental data are in excellent agreement with results obtained from DFT calculations, revealing that the distribution of surface primary and secondary amines readily dictates the CO2 adsorption/desorption properties of the adsorbent.

  9. Phenolic Impregnated Carbon Ablators (PICA) as Thermal Protection Systems for Discovery Missions (United States)

    Tran, Huy K.; Johnson, Christine E.; Rasky, Daniel J.; Hui, Frank C. L.; Hsu, Ming-Ta; Chen, Timothy; Chen, Y. K.; Paragas, Daniel; Kobayashi, Loreen


    This paper presents the development of the light weight Phenolic Impregnated Carbon Ablators (PICA) and its thermal performance in a simulated heating environment for planetary entry vehicles. The PICA material was developed as a member of the Light Weight Ceramic Ablators (LCA's), and the manufacturing process of this material has since been significantly improved. The density of PICA material ranges from 14 to 20 lbm/ft(exp 3), having uniform resin distribution with and without a densified top surface. The thermal performance of PICA was evaluated in the Ames arc-jet facility at cold wall heat fluxes from 375 to 2,960 BtU/ft(exp 2)-s and surface pressures of 0.1 to 0.43 atm. Heat loads used in these tests varied from 5,500 to 29,600 BtU/ft(exp 2) and are representative of the entry conditions of the proposed Discovery Class Missions. Surface and in-depth temperatures were measured using optical pyrometers and thermocouples. Surface recession was also measured by using a template and a height gage. The ablation characteristics and efficiency of PICA are quantified by using the effective heat of ablation, and the thermal penetration response is evaluated from the thermal soak data. In addition, a comparison of thermal performance of standard and surface densified PICA is also discussed.

  10. Catalytic activity of active carbons impregnated before activation of pinewood sawdust and nutshells to be used on the control of atmospheric emissions. (United States)

    Alvim-Ferraz, Maria da Conceição M; Gaspar, Carla Maria T B


    This work analyses the catalytic activity of metal oxides impregnated on activated carbons to be used for the complete oxidation of benzene present in atmospheric emissions. When the impregnation step is performed before CO2 activation, the knowledge about catalytic activity is as yet quite scarce, being the main objective of the study here reported. Pinewood sawdust and nutshells were recycled to produce the activated carbons. Non-expensive metal oxides (CoO, Co3O4 and CrO3) were impregnated. When the impregnation was performed before CO2 activation instead of after activation, at 523 K the kinetic constants were 3.6-4.3 times higher for sawdust carbons, and 2.1-2.7 times higher for nutshell carbons, due to a better metal oxide dispersion on higher mesopore areas and on wider micropores. With Co3O4 as catalyst, a benzene conversion of 90% was reached at a lower temperature than with CrO3 (472 and 558 K, respectively). The carbons impregnated before CO2 activation allowed very good conversions at temperatures that guarantee carbon stability (lower than 575 K). The results obtained led to the conclusion that activated carbon is a suitable support for metal oxide catalyst aiming the complete oxidation of benzene, mainly if an adequately porous texture is induced, proceeding to the impregnation before CO2 activation.

  11. Iron-impregnated granular activated carbon for arsenic removal from drinking water (United States)

    Chang, Qigang

    A new multi-step iron impregnation method was developed in this study to impregnate GAC with a high amount of iron that possesses desired characteristics: stable, even distribution, and high arsenic adsorption capacity. Research was carried out to investigate the impact of the amount of impregnated iron on arsenic adsorption properties: capacity, affinity, and kinetics. Fe-GACs were characterized in terms of the amount, stability, distribution, morphology, and species of impregnated iron. It was found that a high amount of iron was stably impregnated in GAC. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis demonstrated that the impregnated iron was evenly distributed on the internal surface of GAC. Impregnated iron formed nano-size particles and existed in both crystalline (akaganeite) and amorphous iron. Arsenic adsorption tests were conducted using Fe-GACs with iron content of 1.64--28.90% in a low arsenic concentration that is typical for drinking water treatment. The amount of impregnated iron affects arsenic maximum adsorption capacity (qm) but has little impact on the Langmuir constant h (the affinity of adsorbent for adsorbate). The qm for both As(V) and As(III) adsorptions increased significantly with increase of the amount of impregnated iron up to 13.59%. Further increase of iron amounts caused a gradual decrease of qm for As(V). BET analysis indicated impregnated iron possesses the highest surface area at iron content of 13.59%. A new second-order kinetic model was developed to investigate the impact of the amounts of impregnated iron on arsenic adsorption kinetics. With iron content increased from 1.64% to 28.90%, the intrinsic adsorption rate constants reduced from 4.6x10-2 1/hr to 1.18x10 -3 1/hr, which indicates that impregnated iron slows arsenic intraparticle diffusion rate in Fe-GAC. The decreased arsenic intraparticle diffusion rate was most likely caused by reduced pore size of Fe-GACs. Column tests were

  12. Adsorption of low concentration ceftazidime from aqueous solutions using impregnated activated carbon promoted by Iron, Copper and Aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xiang, E-mail: [College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Research Centre for Environmental Pollution Control and Resource Reuse Engineering of Beijing City, Beijing 100029 (China); Zhang, Hua [College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Research Centre for Environmental Pollution Control and Resource Reuse Engineering of Beijing City, Beijing 100029 (China); Sun, Zhirong, E-mail: [College of Environmental & Energy Engineering, Beijing University of Technology, Beijing 100124 (China)


    Graphical abstract: The graphic abstract describes the research that we used modified activated carbons impregnated with iron nitrate, copper nitrate and aluminium nitrate to adsorb ceftazidime from aqueous solution. The surface functional groups of the modified activated carbons were different, and thus resulted in the big difference in the adsorption performance of the modified activated carbons. The theory and the experiments both showed the preferable adsorption of ceftazidime could be achieved on modified activated carbons. - Highlights: • Three modified activated carbons were prepared by impregnating metal nitrate. • Characteristics of the modified activated carbons were analyzed. • Adsorption capacity of ceftazidime on modified activated carbons was improved. • The adsorption behavior of ceftazidime on modified activated carbons were revealed. • The nature of ceftazidime adsorption on modified activated carbons was elucidated. - Abstract: In this paper, three impregnated activated carbon IAC (AC-Cu, AC-Fe, and AC-Al) promoted by Iron, Copper and Aluminum were used for adsorption of ceftazidime. Iron(III), Copper(II) and Aluminum(III) nitrate were used as an impregnant. The IACs were characterized by scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET) surface area analyzer, Fourier transform infrared spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS).The influence of factors, such as ion strength, pH, temperature, initial concentration, and concentration of natural organic matter organic matter on the adsorption process were studied. The adsorption kinetics and isotherms of ceftazidime were studied for the three IACs. The results showed that the adsorption was accurately represented by pseudo-second order model. Under different temperature, the maximum adsorption quantity of ceftazidime on AC-Cu calculated by pseudo-second order kinetic model were 200.0 mg g{sup −1} (298 K), 196.1 mg g{sup −1} (303 K) and 185.2 mg g

  13. Excellent performance of cobalt-impregnated activated carbon in peroxymonosulfate activation for acid orange 7 oxidation. (United States)

    Huang, Tianyin; Chen, Jiabin; Wang, Zhongming; Guo, Xin; Crittenden, John C


    Cobalt-impregnated activated carbon (GAC/Co) was used to produce sulfate radical (SO4·-) from peroxymonosulfate (PMS) in aqueous solution (hereafter called PMS activation). We evaluated its effectiveness by examining the degradation of orange acid 7 (AO7). GAC/Co exhibited high activity to activate PMS to degrade AO7. The degradation efficiency of AO7 increased with increasing dosage of GAC/Co or PMS and elevated temperatures. pH 8 was most favorable for the degradation of AO7 by GAC/Co-activated PMS. The radical quenching experiments indicated that the reactions most likely took place both in the bulk solution and on the surface of GAC/Co. We found that SO4·- played a dominant role in AO7 degradation. Sodium chloride (NaCl) which presents in most dye wastewater had a significant impact on AO7 degradation. Low dosages (NaCl showed a slight inhibitory effect, whereas high dosages (0.8 M) increased the reaction rate. HOCl was confirmed as the main contributor for accelerating AO7 degradation with high concentration of NaCl. In a continuous-flow reaction with an empty-bed contact time of 1.35 min, AO7 was not detected in the effluent for 0 to 18.72 L of treated influent volume (156 h) and 85% removal efficiency was still observed after 40.32 L of treated volume (336 h). Finally, the azo bond and the naphthalene structure in AO7 were destroyed and the degradation pathway was proposed.

  14. Oxygen reduction in acid media: influence of the heat treatment on the FeNPc(1–20 isomer mixture impregnated on carbon blacks and active charcoals

    NARCIS (Netherlands)

    Biloul, A.; Coowar, F.; Contamin, O.; Scarbeck, G.; Savy, M.; van den Ham, D.; Riga, J.; Verbist, J.J.


    Oxygen reduction with the aid of a number of FeNPc(1–2) impregnated carbon supports in sulphuric acid solutions has been investigated. Loading of the carbon samples amounted to about 10 wt.%. After a 10 day stay in the aerated solutions the samples were investigated with rotating disk electrode and

  15. Adsorption of Carbon Dioxide onto Tetraethylenepentamine Impregnated PMMA Sorbents with Different Pore Structure

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Dong Hyun; Park, Cheonggi; Jung, Hyunchul; Kim, Sung Hyun [Korea University, Seoul (Korea, Republic of)


    Poly(methyl methacrylate) (PMMA) supports and amine additives were investigated to adsorb CO{sub 2}. PMMA supports were fabricated by using different ratio of pore forming agents (porogen) to control the BET specific surface area, pore volume and distribution. Toluene and xylene are used for porogens. Supported amine sorbents were prepared by wet impregnation of tetraethylenepentamine (TEPA) on PMMA supports. So we could identify the effect of the pore structure of supports and the quantity of impregnated TEPA on the adsorption capacity. The increased amount of toluene as pore foaming agent resulted in the decreased average pore diameter and the increased BET surface area. Polymer supports with huge different pore distribution could be fabricated by controlling the ratio of porogen. After impregnation, the support with micropore structure is supposed the pore blocking and filling effect so that it has low CO{sub 2} capacity and kinetics due to the difficulty of diffusing. Macropore structure indicates fast adsorption capacity and low influence of amine loading. In case of support with mesopore, it has high performance of adsorption capacity and kinetics. So high surface area and meso-/macro- pore structure is suitable for CO{sub 2} capture.

  16. Catalytic Oxidation of Propylene, Toluene, Carbon Monoxide, and Carbon Black over Au/CeO2 Solids: Comparing the Impregnation and the Deposition-Precipitation Methods (United States)

    Aboukaïs, Antoine; El-Ayadi, Houda; Skaf, Mira; Labaki, Madona; Cousin, Renaud; Abi-Aad, Edmond


    Au/CeO2 solids were prepared by two methods: deposition-precipitation (DP) and impregnation (Imp). The prepared solids were calcined under air at 400°C. Both types of catalysts have been tested in the total oxidation of propylene, toluene, carbon monoxide, and carbon black. Au/CeO2-DP solids were the most reactive owing to the high number of gold nanoparticles and Au+ species and the low concentration of Cl− ions present on its surface compared to those observed in Au/CeO2-Imp solids. PMID:24198730

  17. Adsorption of low concentration ceftazidime from aqueous solutions using impregnated activated carbon promoted by Iron, Copper and Aluminum (United States)

    Hu, Xiang; Zhang, Hua; Sun, Zhirong


    In this paper, three impregnated activated carbon IAC (AC-Cu, AC-Fe, and AC-Al) promoted by Iron, Copper and Aluminum were used for adsorption of ceftazidime. Iron(III), Copper(II) and Aluminum(III) nitrate were used as an impregnant. The IACs were characterized by scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET) surface area analyzer, Fourier transform infrared spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS).The influence of factors, such as ion strength, pH, temperature, initial concentration, and concentration of natural organic matter organic matter on the adsorption process were studied. The adsorption kinetics and isotherms of ceftazidime were studied for the three IACs. The results showed that the adsorption was accurately represented by pseudo-second order model. Under different temperature, the maximum adsorption quantity of ceftazidime on AC-Cu calculated by pseudo-second order kinetic model were 200.0 mg g-1 (298 K), 196.1 mg g-1 (303 K) and 185.2 mg g-1 (308 K). It was much higher than that of AC-Fe and AC-Al. And the process was controlled by both film diffusion and intra particle mass transport. The results also showed that, the Freundlich and Temkin isotherm fit the adsorption well.

  18. Prospective randomized study of carbon-impregnated polytetrafluoroethylene grafts for below-knee popliteal and distal bypass: results at 2 years. The Association Universitaire de Recherche en Chirurgie. (United States)

    Bacourt, F


    The purpose of this prospective randomized multicenter study is to compare patency for a new carbon-impregnated polytetrafluoroethylene (PTFE) graft and standard PTFE grafts. One hundred and sixty patients presenting severe chronic ischemia of the lower extremity were recruited at 17 centers of the French Association Universitaire de Recherche en Chirurgie. Eighty-one carbon-impregnated graft and 79 standard grafts were implanted. The procedure consisted of below-knee femoropopliteal bypass in 83 cases and femorodistal bypass in 77 cases. The minimum duration of the follow-up period was 2 years. Twenty-four patients died during the study. The actuarial primary patency rate, actuarial secondary patency rate, and limb salvage rate were 45%, 53%, and 57% respectively in the carbon-impregnated PTFE group and 35%, 36%, and 47% respectively in the standard PTFE group. The carbon-impregnated graft appeared to achieve better patency than the standard graft but the difference was not statistically significant. Since there was no difference up to 12 months, the study will be continued to determine if further follow-up confirms these findings. In this study we also assessed factors contributing to patency of below-knee prosthetic bypass grafts. Only two factors had a significant influence on patency, i.e., ankle/arm pressure difference greater than 0.25 as opposed to ankle/arm pressure difference less than 0.25 (p < 0.01) and below-knee femoropopliteal bypass as opposed to femorodistal bypass (p < 0.001).

  19. Oxygen reduction in an acid medium - electrocatalysis by CoNPc (1,2) impregnated on a carbon black support - effect of loading and heat treatment

    NARCIS (Netherlands)

    Biloul, A.; Coowar, F.; Contamin, O.; Scarbeck, G.; Savy, M.; van den Ham, D.; van den Ham, D.M.W.; Riga, J.; Verbist, J.J.


    O2 reduction in an acid medium has been investigated on a transition metal macrocycle, CoNPc(1,2), impregnated on a carbon black support with a high dibutylphthalate adsorption value, using a rotating disk electrode and voltammetry techniques described previously, combined with X-ray photoelectron

  20. Study of Fluoride Affinity by Zirconium Impregnated Walnut Shell Carbon in Aqueous Phase: Kinetic and Isotherm Evaluation

    Directory of Open Access Journals (Sweden)

    M. Rajan


    Full Text Available This paper examines the kinetics of fluoride removal from water by the adsorbent zirconium-impregnated walnut-shell carbon (ZIWSC, exploring the mechanisms involved. The dependence of the adsorption of fluoride on the pH of the solution has been studied to achieve the optimum pH value and a better understanding of the adsorption mechanism. The presence of bicarbonate ions in aqueous solution was found to affect the fluoride removal indicating that these anions compete with the sorption of fluoride on adsorbents. The kinetic profile has been modeled using pseudo-first-order model, pseudo-second-order model, and intraparticle diffusion model. The kinetic sorption profiles offered excellent fit with pseudo-second-order model. Adsorption isotherms have been modeled by Langmuir, Freundlich, and Temkin equations, and their constants were determined. The equilibrium adsorption data were fitted reasonably well for Freundlich isotherm model. XRD and SEM patterns of the ZIWSC were recorded to get better insight into the mechanism of adsorption process.

  1. Thermal Degradation Behavior of Siloxane Elastomer Impregnated Carbon Nanotube Areogel Networks

    Energy Technology Data Exchange (ETDEWEB)

    Lewicki, J P; Worsley, M A


    A novel class of nanoporous graphitic carbon foams has been synthesized. Unprecedented properties - electrically conductive, thermally stable (> 1000 C), and mechanically robust. Improved transport properties (DWNT-CA, SWNT-CA) - greater than 100% enhancement in thermal conductivity, 100-400% improvement in electrical conductivity. Rich mechanical deformation behavior (SWNT-CA) - stiff ({approx}100% improvement of elastic modulus), energy dissipation, fracture toughness, and fatigue behavior. Implications for energy-related technologies - hydrogen storage, fusion and fission energy, catalysis, electrochemical energy storage, and composites with foam scaffolds.

  2. Preparation of fluorescence quenched libraries containing interchain disulphide bonds for studies of protein disulphide isomerases

    DEFF Research Database (Denmark)

    Spetzler, J C; Westphal, V; Winther, Jakob R.


    the quenching chromophore (Tyr(NO2)) and Cys(pNpys) activated for reaction with a second thiol. The formation and cleavage of the interchain disulphide bonds in the library were monitored under a fluorescence microscope. Substrates to investigate the properties of protein disulphide isomerase in solution were...

  3. Ionic liquid-impregnated activated carbon for biohydrogen purification in an adsorption unit (United States)

    Yusuf, N. Y.; Masdar, M. S.; Isahak, W. N. R. W.; Nordin, D.; Husaini, T.; Majlan, E. H.; Rejab, S. A. M.; Chew, C. L.


    Biological methods for hydrogen production (biohydrogen) are known as energy intensive and can be operated at ambient temperature and pressure; however, consecutive productions such as purification and separation processes still remain challenging in the industry. Various techniques are used to purify and separate hydrogen. These techniques include the use of sorbents/solvents, membranes and cryogenic distillation. In this study, carbon dioxide (CO2) was purified and separated from biohydrogen to produce high purity hydrogen gas. CO2 capture was studied using the activated carbon (AC) modified with the ionic liquid (IL) choline chloride as adsorbent. The physical and chemical properties of the adsorbents were characterized through XRD, FTIR, SEM-EDX, TGA, and BET analyses. The effects of IL loading, flow rate, temperature, and gas mixture were also investigated based on the absorption and desorption of CO2. The CO2 level in the biohydrogen composition was analyzed using a CO2 gas analyzer. The SEM image indicated that the IL homogeneously covered the AC surface. High IL dispersion inlet enhanced the capability of the adsorbent to capture CO2 gas. The thermal stability and presence of the functionalized group of ILs on AC were analyzed by TGA and FTIR techniques, respectively. CO2 adsorption experiments were conducted using a 1 L adsorber unit. Hence, adsorption technologies exhibit potential for biohydrogen purification and mainly affected by adsorbent ability and operating parameters. This research presents an improved biohydrogen technique based on adsorption technology with novel adsorbents. Two different types of commercial CO2 adsorbents were used in the experiment. Results show that the IL/AC exhibited properties suitable for CO2 adsorption. The IL/AC sample presented a high CO2 uptake of 30 wt. % IL when treated at 30 °C for 6 h under a flow rate of 1 L/min. The presence of IL increased the selectivity of CO2 removal during the adsorption process. This IL

  4. Carbon dioxide adsorption on amine-impregnated mesoporous materials prepared from spent quartz sand. (United States)

    Su, Yiteng; Peng, Lihong; Shiue, Angus; Hong, Gui-Bing; Qian, Zhang; Chang, Chang-Tang


    Mesoporous MCM-41 was synthesized using cetyltrimethyl ammonium bromide (CTAB) as a cationic surfactant and spent quartz sand as the silica source. Modification of the mesoporous structure to create an absorbent was then completed using 3-aminopropyltrimethoxysilane. Amine-Quartz-MCM (The A-Q-MCM) adsorbents were then characterized by N2 adsorption/desorption, elemental analysis (EA), X-ray fluorescence (XRF), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), as well as the carbon dioxide (CO2) adsorption/desorption performance. In this study, spent quartz sand was utilized to synthesize Quartz-MCM (Q-MCM) and the amine functionalized material, A-Q-MCM, which exhibited a higher uptake of CO2 at room temperature compared with the nongrafted material. The results showed that Q-MCM is similar to MCM-41 synthesized using commercial methods. The surface area, pore volume, and pore diameter were found to be as high as 1028 m2/g, 0.907 cm3/g, and 3.04 nm, respectively. Under the condition of CO2 concentration of 5000 ppm, retention time of 50 cc/min, and the dosage of 1 g/cm3, the mean adsorption capacity of CO2 onto A-Q-MCM was about 89 mg/g, and the nitrogen content of A-Q-MCM was 2.74%. The adsorption equilibrium was modeled well using a Freundlich isotherm. Implications: In this study, spent quartz sand was utilized to synthesize Q-MCM. The amine functionalized material exhibited a higher uptake of CO2 at room temperature compared with the nongrafted material. The results showed that Q-MCM is similar to MCM-41 synthesized using commercial methods. The adsorption equilibrium was modeled well using a Freundlich isotherm.

  5. Controlled synthesis of carbon-supported Pt{sub 3}Sn by impregnation-reduction and performance on the electrooxidation of CO and ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Rodriguez, S.; Pena, M.A.; Fierro, J.L.G.; Rojas, S. [Grupo Energia y Quimica Sostenibles, Instituto de Catalisis y Petroleoquimica, CSIC, C/Marie Curie 2, E-28049 Madrid (Spain)


    The paper discusses experimental features relevant to the synthesis of carbon-supported Pt{sub 3}Sn nanosized particles by impregnation-reduction of the salt precursors in carbon. Colloidal techniques are proposed as the most suitable ones for obtaining carbon-supported nanosized Pt{sub 3}Sn particles. In most cases, the electrocatalysts obtained have a wide range of Pt and Sn phases, including bimetallic ones. The synthesis of similar materials by impregnating readily available precursors such as SnCl{sub 2} and H{sub 2}PtCl{sub 6} yields Pt-enriched catalyst precursors. In order to obtain electrocatalysts with the desired Pt:Sn = 3 atomic stoichiometry, it is necessary to eliminate chloride ions prior to thermal treatments. Microscopy characterization and thermal stability studies of the fresh and treated bimetallic materials reveal that if such ions are present, Sn is eliminated as volatile SnCl{sub x} species at around 120-130 C. Chloride elimination is achieved by ageing the catalyst precursor in water to ensure the complete hydrolysis of the SnCl{sub 2} precursor. This treatment should be performed once SnCl{sub 2} has been deposited on the carbon to avoid the formation of large Sn-oxide aggregates. A further thermal treatment in hydrogen results in the formation of the desired Pt{sub 3}Sn intermetallic phase. The performance of the Pt{sub 3}Sn/C samples in the CO and ethanol electrooxidation reaction has been studied by means of electrochemical techniques. The electrocatalysts prepared by the impregnation-reduction approach match the performance of the state-of-the-art Pt{sub 3}Sn samples prepared by colloidal techniques. (author)

  6. Preparation of green alga-based activated carbon with lower impregnation ratio and less activation time by potassium tartrate for adsorption of chloramphenicol. (United States)

    Zhu, Xiuzhen; Gao, Yuan; Yue, Qinyan; Kan, Yujiao; Kong, Wenjia; Gao, Baoyu


    Potassium tartrate (C 4 H 6 K 2 O 7 ) was utilized as a novel activating agent to prepare activated carbon with relatively high specific surface area by using less activating agent and activation time from marine waste-green alga (Enteromorpha prolifera) for the first time. The influences of activation temperature, impregnation ratio and activation time on the pore structure were investigated to obtain the optimum conditions (activation temperature: 700°C, impregnation ratio: 1:1, and activation time: 30min). Meanwhile, the activation temperature was evaluated to be the essential factor that dominated the form of pore structure in activated carbon. The green alga-based activated carbon that was prepared under optimum conditions has shown the high surface area of 1692m 2 /g and total pore volume of 1.22cm 3 /g, which could be used as an effective adsorbent to remove chloramphenicol. The thermodynamic data of chloramphenicol were well fitted by Langmuir isotherm model and the green alga-based activated carbon has showed high adsorption capacity of 709.2mg/g towards chloramphenicol. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Optimization of process condition for the preparation of amine-impregnated activated carbon developed for CO2capture and applied to methylene blue adsorption by response surface methodology. (United States)

    Das, Dipa; Meikap, Bhim C


    The present research describes the optimal adsorption condition for methylene blue (MB). The adsorbent used here was monoethanol amine-impregnated activated carbon (MEA-AC) prepared from green coconut shell. Response surface methodology (RSM) is the multivariate statistical technique used for the optimization of the process variables. The central composite design is used to determine the effect of activation temperature, activation time and impregnation ratio on the MB removal. The percentage (%) MB adsorption by MEA-AC is evaluated as a response of the system. A quadratic model was developed for response. From the analysis of variance, the factor which was the most influential on the experimental design response has been identified. The optimum condition for the preparation of MEA-AC from green coconut shells is the temperature of activation 545.6°C, activation time of 41.64 min and impregnation ratio of 0.33 to achieve the maximum removal efficiency of 98.21%. At the same optimum parameter, the % MB removal from the textile-effluent industry was examined and found to be 96.44%.

  8. On the disulphide bonds of rhodopsins.


    Al-Saleh, S; Gore, M; Akhtar, M.


    Carboxymethylation using 14C- or 3H-labelled iodoacetic acid has been used to identify the cysteine residues in bovine rhodopsin involved in the formation of the two intramolecular disulphide bridges. Iodo[2-14C]acetic acid was used to modify 5.8-5.9 residues of cysteine under non-reducing conditions. After dialysis and reduction of disulphide bridges by 2-mercaptoethanol, iodo[2-3H]acetic acid was employed to covalently modify 3.3-3.6 residues of cysteine. Peptide purification and sequencing...

  9. Preparation and formation mechanism of porous carbon nanosheets by thermal decomposition of polyvinyl alcohol films impregnated with zinc (II) and nitrate ions (United States)

    Hattori, Yoshiyuki; Kojima, Rikio; Sagisaka, Kento; Umeda, Motoki; Tanaka, Toshihisa; Kondo, Atsushi; Iiyama, Taku; Kimura, Mutsumi; Fujimoto, Hiroyuki; Touhara, Hidekazu


    Porous carbon nanosheets (PCNS) with high surface areas were prepared by thermal decomposition of polyvinyl alcohol (PVA) films impregnated with Zn2+ and NO3-. Through this simple preparation method that required no additional activation processes, curved carbon nanosheets (1600 m2 g-1) and bimodal pore structure consisting of micropores and mesopores. Because of their unique structural properties, the PCNS are attractive for use as electrode materials. The electrode performance of the PCNS was investigated in 1-M tetraethylammonium tetrafluoroborate ((C2H5)4NBF4) in propylene carbonate. The PCNS electrodes displayed high specific capacitance (86 F g-1 for cations and 115 F g-1 for anions). They also showed exceptionally high rate performance with ∼90% capacitance retention at current densities up to 2 A g-1 because their nanosheet structure allowed the rapid diffusion of ions inside the electrode.

  10. Effects of Weathering on Impregnated Charcoal Performance. (United States)


    Penetration of 1 3 1 ICH3 at 21°C for new (not used) Coconut Shell Commercial Carbons (impregnated) With and Without Prehumidification... coconut charcoal to retain the krypton and xenon released during the operation of the Oak Ridge Homogeneous Test Reactor. The carbon was not...include both coconut shell and coal as source materials. The impregnations include a mixture of KI and elementary iodine and tertiary amines, either

  11. Exploring atomic defects in molybdenum disulphide monolayers

    KAUST Repository

    Hong, Jinhua


    Defects usually play an important role in tailoring various properties of two-dimensional materials. Defects in two-dimensional monolayer molybdenum disulphide may be responsible for large variation of electric and optical properties. Here we present a comprehensive joint experiment-theory investigation of point defects in monolayer molybdenum disulphide prepared by mechanical exfoliation, physical and chemical vapour deposition. Defect species are systematically identified and their concentrations determined by aberration-corrected scanning transmission electron microscopy, and also studied by ab-initio calculation. Defect density up to 3.5 × 10 13 cm \\'2 is found and the dominant category of defects changes from sulphur vacancy in mechanical exfoliation and chemical vapour deposition samples to molybdenum antisite in physical vapour deposition samples. Influence of defects on electronic structure and charge-carrier mobility are predicted by calculation and observed by electric transport measurement. In light of these results, the growth of ultra-high-quality monolayer molybdenum disulphide appears a primary task for the community pursuing high-performance electronic devices.

  12. Effects of first-row transition metals and impregnation ratios on the physicochemical properties of microwave-assisted activated carbons from wood biomass. (United States)

    Thue, Pascal S; Lima, Eder C; Sieliechi, Joseph M; Saucier, Caroline; Dias, Silvio L P; Vaghetti, Julio C P; Rodembusch, Fabiano S; Pavan, Flávio A


    First-row transition metals (Co, Ni, Cu and Zn) were successfully used in the preparation of activated carbons from wood biomass via microwave-assisted irradiation. Physical-chemical properties of the produced materials (MWAC) were studied by nitrogen adsorption-desorption curves, SEM, FTIR, UV-vis DRS and synchronous fluorescence spectroscopy, CHN elemental analysis, TGA/DTG, pHzpc, hydrophobic properties, and total acidity and basicity groups. Results showed that the metals were bound successfully in different amounts with surface functional groups of the wood biomass through ion exchange and surface complexation interaction during the impregnation step. Zn(2+) and Cu(2+) formed the most complexes. MWAC impregnated with Zn(2+) showed higher pore volumes and surface areas, followed by Cu(2+), Co(2+) and Ni(2+), independently of the ratio used. As the metal : biomass ratio was increased from 0.5 to 2, the surface area of MWAC increased from 300 to 620m(2)g(-1) for Co-MC, 260 to 381m(2)g(-1) for Ni-MC, 449 to 765m(2)g(-1) for Cu-MC and from 572 to 1780m(2)g(-1) for Zn-MC. The samples showed high values of carbon contents and oxygen-containing groups. An adsorption experiment revealed that samples prepared using ZnCl2 showed the highest sorption capacities (qe) for the tested adsorbates, followed by CuCl2, CoCl2 and NiCl2. These results matched with the surface areas and pore volumes trends, which were found to follow atomic number and melting point trends-Ni(II)phenol>bisphenol A>hydroquinone>4-nitro phenol>2-naphtol>paracetamol>caffeine>resorcinol. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Ácido giberélico, bissulfureto de carbono e ácido 2-4 cloroetil fosfônico e a dormência e produtividade de tubérculos de batata Giberellic acid, carbon-disulphide and 2-4 chloro-ethyl phosphonic and the dormancy and yield of potato tubers

    Directory of Open Access Journals (Sweden)

    Ricardo Antonio Ayub


    Full Text Available Com o objetivo de avaliar a eficiência do ácido giberélico, bissulfureto de carbono e ácido 2-4 cloroetil-fosfônico (EthrellR na quebra de dormência e na produção de batata, cv. "Marijke", foi conduzido um ensaio no período de 1990/ 91 em Piraí do Sul, PR . A superioridade do tratamento com o ácido 2-4-cloroetil-fosfônico em relação ao ácido giberélico e ao bissulfureto de carbono, aliada a sua facilidade de aplicação, justifica a sua recomendação com vistas a quebra de dormência de tubérculos do genótipo de batata em estudo, para a região de Piraí do Sul, PR, onde a dose de 842 mg.L-1 de EthrellR ocasionou a produção máxima de 23395 kg/ha.In order to evaluate the efficiency of giberellic acid, carbon-disulphide, and 2-4 chloro-ethyl phosphonic acid (EthrellR on dormancy breaking and yield of potato cv. 'Marijke', an essay was conducted at Piraí do Sul, PR, Brazil, during 1990/1991. The superiority of the EthrellR treatment over giberellic acid and carbon-disulphide, and its easy application, justify its use for dormancy breaking of potato tubers, for the studied genotype and location, at the rate of 842 mg.L-1, resulting in a potato yield of 23,395 kg/ha.

  14. Engineering and introduction of de novo disulphide bridges in ...

    Indian Academy of Sciences (India)

    In this study, Disulphide by Design software, homology modelling and moleculardynamics simulations were used to select appropriate amino acid pairs for the introduction of disulphide bridge toimprove protein thermostability. The thermostability of the wild-type and three selected mutant enzymes wereevaluated by half-life ...

  15. Adsorption Isotherm of Chromium (Vi) into Zncl2 Impregnated Activated Carbon Derived by Jatropha Curcas Seed Hull (United States)

    Mohammad, M.; Yakub, I.; Yaakob, Z.; Asim, N.; Sopian, K.


    Hexavalent chromium is carcinogenic and should be removed from industrial wastewater before discharged into water resources. Adsorption by using activated carbon from biomass is an economic and conventional way on removing the heavy metal ions from wastewater. In this research, activated carbon is synthesized from Jatropha curcas L. seed hull through chemical activation with ZnCl2 and carbonized at 800 °C (JAC/ZnCl2). The activated carbon has been characterized using FTIR, SEM-EDX, BET and CHNS-O analyzer. Adsorption isotherms have been analysed using Langmuir and Freundlich models to determine its removal mechanism. The maximum adsorption capacity of Cr (VI) metal ions onto JAC/ZnCl2 activated carbon is 25.189 mg/g and following Langmuir isotherm model which is monolayer adsorption.

  16. Hydrogen sorption and permeability of compacted LiBH4 nanoconfined into activated carbon nanofibers impregnated with TiO2 (United States)

    Sitthiwet, Chongsutthamani; Thiangviriya, Sophida; Thaweelap, Natthaporn; Meethom, Sukanya; Kaewsuwan, Dechmongkhon; Chanlek, Narong; Utke, Rapee


    Activated carbon nanofibers impregnated with titanium (IV) oxide (TiO2), denoted as ACNF-Ti are prepared by carbonization and activation of electrospun nanofibers of polyacrylonitrile (PAN)-titanium (IV) isopropoxide composite. Pristine LiBH4 and nanoconfined LiBH4 in ACNF-Ti, denoted as LiBH4-ACNF-Ti are compacted under the pressures of 434 and 868 MPa. Dehydrogenation temperature of compacted LiBH4 increases (up to 485 °C) with compaction pressure due to poor hydrogen permeability. In the case of compacted LiBH4-ACNF-Ti, major dehydrogenation temperature at 352-359 °C and hydrogen content liberated (74-76% of theoretical capacity) are obtained despite enhanced compaction pressure. Mechanical stability during cycling of compacted LiBH4-ACNF-Ti is achieved. Although hydrogen permeability of compacted LiBH4-ACNF-Ti improves with enhanced compaction pressure, detrimental kinetics and reversibility are detected. Since the fibrous structure of ACNF-Ti are brittle, the broken and/or shorten fibers are observed after compaction under high pressure. The latter results in not only inferior nanoconfinement of LiBH4 into ACNF-Ti, but also agglomeration of hydride materials upon cycling.

  17. Development of manufacturing process for large-diameter composite monofilaments by pyrolysis of resin-impregnated carbon-fiber bundles (United States)

    Bradshaw, W. G.; Pinoli, P. C.; Vidoz, A. E.


    Large diameter, carbon-carbon composite, monofilaments were produced from the pyrolysis of organic precursor resins reinforced with high-strenght carbon fibers. The mechanical properties were measured before and after pyrolysis and the results were correlated with the properties of the constituents. The composite resulting from the combination of Thornel 75 and GW-173 resin precursor produced the highest tensile strength. The importance of matching strain-to-failure of fibers and matrix to obtain all the potential reinforcement of fibers is discussed. Methods are described to reduce, within the carbonaceous matrix, pyrolysis flaws which tend to reduce the composite strength. Preliminary studies are described which demonstrated the feasibility of fiber-matrix copyrolysis to alleviate matrix cracking and provide an improved matrix-fiber interfacial bonding.

  18. Synthesis and Electrochemical Evaluation of Carbon Supported Pt-Co Bimetallic Catalysts Prepared by Electroless Deposition and Modified Charge Enhanced Dry Impregnation

    Directory of Open Access Journals (Sweden)

    John Meynard M. Tengco


    Full Text Available Carbon-supported bimetallic Pt-Co cathode catalysts have been previously identified as higher activity alternatives to conventional Pt/C catalysts for fuel cells. In this work, a series of Pt-Co/C catalysts were synthesized using electroless deposition (ED of Pt on a Co/C catalyst prepared by modified charge enhanced dry impregnation. X-ray diffraction (XRD and scanning transmission electron microscopy (STEM characterization of the base catalyst showed highly dispersed particles. A basic ED bath containing PtCl62− as the Pt precursor, dimethylamine borane as reducing agent, and ethylenediamine as stabilizing agent successfully targeted deposition of Pt on Co particles. Simultaneous action of galvanic displacement and ED resulted in Pt-Co alloy formation observed in XRD and energy dispersive X-ray spectroscopy (XEDS mapping. In addition, fast deposition kinetics resulted in hollow shell Pt-Co alloy particles while particles with Pt-rich shell and Co-rich cores formed with controlled Pt deposition. Electrochemical evaluation of the Pt-Co/C catalysts showed lower active surface but much higher mass and surface activities for oxygen reduction reaction compared to a commercial Pt/C fuel cell catalyst.

  19. Numerical analysis of the influence of the impregnation ratio on the microporous structure formation of activated carbons, prepared by chemical activation of waste biomass with phosphoric(V) acid (United States)

    Kwiatkowski, Mirosław; Kalderis, Dimitrios; Diamadopoulos, Evan


    This paper presents the results of the application of new mathematical adsorption models with the unique numerical fast multivariate identification procedure as the tool for analysing the influence of the impregnation ratio i.e. activator to the raw material mass ratio on the microporous structure development of the activated carbons, obtained from sugarcane bagasse and rice husk by chemical activation with phosphoric(V) acid.

  20. 2LiBH{sub 4}–MgH{sub 2} nanoconfined into carbon aerogel scaffold impregnated with ZrCl{sub 4} for reversible hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Utke, Rapee, E-mail: [School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Thiangviriya, Sophida [School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Javadian, Payam; Jensen, Torben R. [Center for Energy Materials, iNANO and Department of Chemistry, University of Aarhus, Aarhus C8000 (Denmark); Milanese, Chiara [Pavia Hydrogen Lab, C. S.G. I.–Department of Chemistry–Physical Chemistry Division, University of Pavia, Pavia 27100 (Italy); Klassen, Thomas; Dornheim, Martin [Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Geesthacht 21502 (Germany)


    Nanoconfinement of 2LiBH{sub 4}–MgH{sub 2} composite into carbon aerogel scaffold (CAS) impregnated with zirconium (IV) chloride (ZrCl{sub 4}) for reversible hydrogen storage is proposed. Nanoconfined samples prepared with hydride:ZrCl{sub 4}-doped CAS weight ratios of 1:1, 1:2, and 1:3 are prepared by melt infiltration technique. Successful nanoconfinement of all samples is confirmed and it is found that the sample with high content of hydride with respect to ZrCl{sub 4}-doped CAS (1:1 weight ratio) shows partial pore blocking. The most suitable hydride:ZrCl{sub 4}-doped CAS weight ratio providing the best performance based on dehydrogenation temperature and kinetics as well as hydrogen storage capacity is 1:2. Reduction of dehydrogenation temperature and faster kinetics are obtained after doping with ZrCl{sub 4}. Up to 97 and 93% of theoretical hydrogen storage capacity are released and reproduced after four cycles of nanoconfined sample with ZrCl{sub 4} (1:2 weight ratio). Deficient hydrogen content with respect to theoretical capacity can be due to partial dehydrogenation during melt infiltration and formation of thermally stable [B{sub 12}H{sub 12}]{sup 2-} phases during cycling. - Highlights: • Nanoconfined 2LiBH4–MgH2 in carbon aerogel scaffold (CAS) doped with ZrCl4. • Studies of hydride: ZrCl4-doped CAS weight ratio affecting on H2 desorption. • Reduction of H2 desorption temperature and faster kinetics after ZrCl4 doping. • Up to 97 and 93% of theoretical H2 capacity released and reproduced, respectively.

  1. Oil-Impregnated Polyethylene Films (United States)

    Mukherjee, Ranit; Habibi, Mohammad; Rashed, Ziad; Berbert, Otacilio; Shi, Shawn; Boreyko, Jonathan


    Slippery liquid-infused porous surfaces (SLIPS) minimize the contact angle hysteresis of a wide range of liquids and aqueous food products. Although hydrophobic polymers are often used as the porous substrate for SLIPS, the choice of polymer has been limited to silicone-based or fluorine-based materials. Hydrocarbon-based polymers, such as polyethylene, are cost effective and widely used in food packaging applications where SLIPS would be highly desirable. However, to date there have been no reports on using polyethylene as a SLIPS substrate, as it is considered highly impermeable. Here, we show that thin films of low-density polyethylene can be stably impregnated with carbon-based oils without requiring any surface modification. Wicking tests reveal that oils with sufficient chemical compatibility follow Washburn's equation. The nanometric effective pore size of the polyethylene does result in a very low wicking speed, but by using micro-thin films and a drawdown coater, impregnation can still be completed in under one second. The oil-impregnated polyethylene films promoted ultra-slippery behavior for water, ketchup, and yogurt while remaining durable even after being submerged in ketchup for over one month. This work was supported by Bemis North America (AT-23981).

  2. In Situ Densification Utilizing a Low-Viscosity Wetting Impregnant that Greating Reduces Processing Time to Produce Uniform Density Carbon-Carbon Composites

    National Research Council Canada - National Science Library

    Hoffman, Wesley


    ... (the process of graphitization). Despite these properties, however, the use of carbon-carbon composites has been limited both because of their high cost and their oxidation at elevated temperatures...

  3. In Situ Densification Utilizing a Low-Viscosity Wetting Impregnant that Greating Reduces Processing Time to Produce Uniform Density Carbon-Carbon Composites

    National Research Council Canada - National Science Library

    Hoffman, Wesley


    High-performance carbon-carbon (C-C) composites possess a unique set of properties that make them desirable materials for high-temperature structural uses such as in rocket propulsion components, hypersonic vehicles, and aircraft brakes...

  4. Diallyl disulphide as natural organosulphur friction modifier via the in-situ tribo-chemical formation of tungsten disulphide (United States)

    Rodríguez Ripoll, Manel; Totolin, Vladimir; Gabler, Christoph; Bernardi, Johannes; Minami, Ichiro


    The present work shows a novel method for generating in-situ low friction tribofilms containing tungsten disulphide in lubricated contacts using diallyl disulphide as sulphur precursor. The approach relies on the tribo-chemical interaction between the diallyl disulphide and a surface containing embedded sub-micrometer tungsten carbide particles. The results show that upon sliding contact between diallyl disulphide and the tungsten-containing surface, the coefficient of friction drops to values below 0.05 after an induction period. The reason for the reduction in friction is due to tribo-chemical reactions that leads to the in-situ formation of a complex tribofilm that contains iron and tungsten components. X-ray photoelectron spectroscopy analyses indicate the presence of tungsten disulphide at the contact interface, thus justifying the low coefficient of friction achieved during the sliding experiments. It was proven that the low friction tribofilms can only be formed by the coexistence of tungsten and sulphur species, thus highlighting the synergy between diallyl disulphide and the tungsten-containing surface. The concept of functionalizing surfaces to react with specific additives opens up a wide range of possibilities, which allows tuning on-site surfaces to target additive interactions.

  5. Alkaline direct ethanol fuel cell performance using alkali-impregnated polyvinyl alcohol/functionalized carbon nano-tube solid electrolytes (United States)

    Huang, Chien-Yi; Lin, Jia-Shiun; Pan, Wen-Han; Shih, Chao-Ming; Liu, Ying-Ling; Lue, Shingjiang Jessie


    This study investigates the application of a polyvinyl alcohol (PVA)/functionalized carbon nano-tubes (m-CNTs) composite in alkaline direct ethanol fuel cells (ADEFC). The m-CNTs are functionalized with PVA using the ozone mediation method, and the PVA composite containing the modified CNTs is prepared. Adding m-CNT into the PVA matrix enhances the alkaline uptake and the ionic conductivity of the KOH-doped electrolyte. Meanwhile, the m-CNT-containing membrane exhibited a lower swelling ratio and suppressed ethanol permeability compared to the pristine PVA film. The optimal condition for the ADEFC is determined to be under operation at an anode feed of 3 M ethanol in a 5 M KOH solution (at a flow rate of 5 cm3 min-1) with a cathode feed of moisturized oxygen (with a flow rate of 100 cm3 min-1) and the KOH-doped PVA/m-CNT electrolyte. We achieved a peak power density value of 65 mW cm-2 at 60 °C, which is the highest among the ADEFC literature data and several times higher than the proton-exchange direct ethanol fuel cells using sulfonated membrane electrolytes. Therefore, the KOH-doped PVA/m-CNT electrolyte is a suitable solid electrolyte for ADEFCs and has potential for commercialization in alkaline fuel cell applications.

  6. Removal of lead and bisphenol A using magnesium silicate impregnated palm-shell waste powdered activated carbon: Comparative studies on single and binary pollutant adsorption. (United States)

    Choong, Choe Earn; Ibrahim, Shaliza; Yoon, Yeomin; Jang, Min


    In this work, palm shell waste powder activated carbon coated by magnesium silicate (PPAC-MS) were synthesized by the impregnation of magnesium silicate (MgSiO3) using economical material (silicon dioxide powder) via mild hydrothermal approach for the first time. As an effective adsorbent, PPAC-MS simultaneously removes BPA and Pb(II) in single and binary mode. Surprisingly, PPAC-MS exhibited a homogeneous thin plate mesh-like structure, as well as meso- and macropores with a high surface area of 772.1m2g-1. Due to its specific morphological characteristics, PPAC-MS had adsorption capacities of Pb(II) as high as 419.9mgg-1 and 408.8mgg-1 in single mode and binary mode based on Freudliuch isotherm model while those for BPA by PPAC-MS were 168.4mgg-1 and 254.7mgg-1 for single mode and binary modes corresponding to Langmuir isotherm model. Experiment results also indicated that the synergistic removal of BPA occurred because the precipitation process of Pb(II) leads to the co-precipitation of BPA with Pb(OH)2 compound. PPAC-MS showed a good reusability for 5 regeneration cycles using Mg(II) solution followed by thermal treatment. Overall, PPAC-MS has a high potential in the treatment process for wastewater containing both toxic heavy metals and emerging pollutants due to its high sorption capacities and reusability. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Liquid-liquid extraction of cadmium(II by TIOACl (tri-iso-octylammonium chloride ionic liquid and its application to a TIOACl impregnated carbon nanotubes system

    Directory of Open Access Journals (Sweden)

    Alguacil, Francisco J.


    Full Text Available The extraction of cadmium(II by the ionic liquid (R3NH+Cl- (R: tri-iso-octyl in Exxsol D100 from hydrochloric acid solution has been investigated. The extraction reaction is exothermic. The numerical analysis of metal distribution data suggests the formation of R3NH+CdCl3− and (R3NH+2CdCl42− species in the organic phase. The results obtained for cadmium(II distribution have been implemented in an impregnated multi-walled carbon nanotubes system. The influence of aqueous solution stirring speed (250–2000 min−1, adsorbent dosage (0.05–0.2 g and temperature (20 °C–60 °C on cadmium adsorption have been investigated.Se ha estudiado la extracción de cadmio(II, de disoluciones en medio HCl, por el líquido iónico (R3NH+Cl- (R: tri-iso-octyl disuelto en Exxsol D100. La reacción de extracción tiene un carácter exotérmico. El análisis numérico de la distribución del metal sugiere la formación de las especies R3NH+CdCl3− y (R3NH+2CdCl42− en la fase orgánica. Estos resultados se han implementado en un sistema que utiliza nanotubos de carbono de pared múltiple impregnados con este líquido iónico. Se han investigado diversas variables experimentales: velocidad de agitación de la disolución acuosa (250–2000 min−1, adición del adsorbente (0,05–0,2 g y temperatura (20–60 °C.

  8. Thiol-disulphide oxidoreductase modules in the low-GC Gram-positive bacteria

    NARCIS (Netherlands)

    Kouwen, Thijs R. H. M.; van der Goot, Annemieke; Dorenbos, Ronald; Winter, Theresa; Antelmann, Haike; Plaisier, Marie-Claire; Quax, Wim J.; van Dijl, January Maarten; Dubois, Jean-Yves F.

    Disulphide bond formation catalysed by thioldisulphide oxidoreductases (TDORs) is a universally conserved mechanism for stabilizing extracytoplasmic proteins. In Escherichia coli, disulphide bond formation requires a concerted action of distinct TDORs in thiol oxidation and subsequent quinone

  9. Oxygen reduction in acid media: effect of iron substitution by cobalt on heat-treated naphthalocyanine impregnations supported on preselected carbon blacks

    NARCIS (Netherlands)

    Biloul, A.; Contamin, O.; Scarbeck, G.; Savy, M.; van den Ham, D.; Riga, J.; Verbist, J.J.


    FeNPc(1.2) impregnations were investigated at various loadings using a rotating-disk electrode, voltammetry and X-ray photoelectron spectroscopy (XPS) techniques. Optimal activity takes place at monolayer coverage, and major demetallation occurs after prolonged exposure to acid solution. The

  10. Investigation of thiol-disulphide balance in patients with acute urticaria and chronic spontaneous urticaria. (United States)

    Akbas, Ayse; Kilinc, Fadime; Sener, Sertac; Aktaş, Akın; Baran, Pervin; Ergin, Merve


    Thiol-disulphide balance plays a major role in health and diseases. This balance may be disrupted by various diseases. We aimed to determine status of the effect of thiol-disulphide balance in urticaria. We aimed to investigate the thiol-disulphide balance in patients with acute urticaria (AUP) and chronic spontaneous urticaria (CSU). Study included 53 AUP and 47 healthy controls plus 57 patients with chronic spontaneous urticaria (CSUP) and 57 healthy controls. Levels of native thiols, disulphides and total thiols were evaluated in plasma using a new and automated spectrophotometric method. Ratios of disulphides/total thiols, disulphides/native thiols and native thiols/total thiols were calculated. For AU, there was no statistical difference compared to control group in levels of native thiols, disulphides and total thiols. For CSU, however, there was an increase in levels of native thiols, disulphides and total thiols and the ratio of thiol/disulphide in favour of disulphide. Thiol-disulphide balance was not affected by AU but shifted towards to disulphide in CSU indicating the presence of oxidative stress (OS).

  11. Development of a Rapid Thermoplastic Impregnation Device

    NARCIS (Netherlands)

    Weustink, A.P.D.


    A melt impregnation device for rapid thermoplastic impregnation of fiber bundles has been developed through modeling and experiments. The basic principles behind the thermoplastic impregnation process are investigated and the properties needed for a successful thermoplastic impregnation device are

  12. Growth of molybdenum disulphide using iodine as transport material

    Indian Academy of Sciences (India)

    In the present paper an attempt has been made to describe the chemical vapor transport (CVT) technique used for the growth of molybdenum disulphide (MoS2) single crystals. Iodine (I2) is used as transporting material for this purpose. The energy dispersive analysis by X-ray (EDAX) confirmed the stoichiometry of the ...

  13. Growth of molybdenum disulphide using iodine as transport material

    Indian Academy of Sciences (India)

    Abstract. In the present paper an attempt has been made to describe the chemical vapor transport (CVT) technique used for the growth of molybdenum disulphide (MoS2) single crystals. Iodine (I2) is used as transporting material for this purpose. The energy dispersive analysis by X-ray (EDAX) confirmed the stoichiometry ...

  14. Flexible Phenolic Impregnated Felt Project (United States)

    National Aeronautics and Space Administration — During this program Fiber Materials, Inc. (FMI) will develop innovative yet practical methods for preparing Phenolic Impregnated Felt (PIF) materials for thermal...

  15. Gene regulation in response to protein disulphide isomerase deficiency

    DEFF Research Database (Denmark)

    Nørgaard, Per; Tachibana, Christine; Bruun, Anette W


    We have examined the activities of promoters of a number of yeast genes encoding resident endoplasmic reticulum proteins, and found increased expression in a strain with severe protein disulphide isomerase deficiency. Serial deletion in the promoter of the MPD1 gene, which encodes a PDI1-homologue...... element. The sequence (GACACG) does not resemble the unfolded protein response element. It is present in the upstream regions of the MPD1, MPD2, KAR2, PDI1 and ERO1 genes....

  16. Bandgap tunability at single-layer molybdenum disulphide grain boundaries

    KAUST Repository

    Huang, Yu Li


    Two-dimensional transition metal dichalcogenides have emerged as a new class of semiconductor materials with novel electronic and optical properties of interest to future nanoelectronics technology. Single-layer molybdenum disulphide, which represents a prototype two-dimensional transition metal dichalcogenide, has an electronic bandgap that increases with decreasing layer thickness. Using high-resolution scanning tunnelling microscopy and spectroscopy, we measure the apparent quasiparticle energy gap to be 2.40±0.05 eV for single-layer, 2.10±0.05 eV for bilayer and 1.75±0.05 eV for trilayer molybdenum disulphide, which were directly grown on a graphite substrate by chemical vapour deposition method. More interestingly, we report an unexpected bandgap tunability (as large as 0.85±0.05 eV) with distance from the grain boundary in single-layer molybdenum disulphide, which also depends on the grain misorientation angle. This work opens up new possibilities for flexible electronic and optoelectronic devices with tunable bandgaps that utilize both the control of two-dimensional layer thickness and the grain boundary engineering.

  17. Impregnated Metal-Organic Frameworks for the Removal of Toxic Industrial Chemicals (United States)


    enhance reactivity towards toxic chemicals. Typical impregnations of current materials, such as ASZM-TEDA, are done in an aqueous and/or ammoniacal ...ammonium hydroxide/ammonium carbonate/water solution (referred to as ammoniacal solution). Clearly, this solution would not be suitable for impregnation

  18. Protein-disulphide isomerase and prolyl isomerase act differently and independently as catalysts of protein folding. (United States)

    Lang, K; Schmid, F X


    Two enzymes are now known that catalyse slow steps in protein folding. Peptidyl-prolyl cis-trans isomerase catalyses the cis-trans isomerization of Xaa-Pro peptide bonds in oligopeptides and during the refolding of several proteins. The other enzyme, protein-disulphide isomerase, accelerates the reactivation of reduced proteins, presumably by catalysis of thiol-disulphide exchange reactions. Recent evidence indicates that the beta-subunit of prolyl 4-hydroxylase, an enzyme involved in collagen biosynthesis, is identical with disulphide isomerase. On the basis of this important finding, it was suggested that disulphide isomerase accelerates protein folding, not by 'reshuffling' incorrect disulphide bonds, but in the same way as prolyl isomerase by catalysing proline isomerization which is known to be important for the folding of collagen and other proteins. Here we show that the catalytic activities of these two enzymes are different. Disulphide isomerase accelerates the reformation of native disulphide bonds during protein reoxidation. We find no evidence that this enzyme can catalyse the isomerization of proline peptide bonds, a reaction efficiently accelerated by prolyl isomerase. When both enzymes are present simultaneously during protein folding, they act independently of one another.

  19. Thiol-disulphide homoeostasis as an oxidative stress marker in men with varicocele. (United States)

    Gul, M; Bugday, M S; Erel, O


    Oxidative stress is the most common factor leading to infertility in men with varicocele. Reactive oxygen species and other markers of oxidative stress are measured to predict the extent of oxidative stress. Thiol groups are important antioxidants and essential molecules protecting organism against the harmful effects of reactive oxygen species. Thiol-disulphide homoeostasis is a unique, easy and new method to demonstrate oxidative stress. The aim of this study was to determine thiol-disulphide homoeostasis as an oxidative stress marker in infertile men with varicocele. The hormonal profile and parameters of thiol-disulphide homoeostasis were studied in 46 infertile men with varicocele, 70 fertile men with varicocele and 37 fertile controls. Infertile men with varicocele had significantly higher disulphide concentrations and disulphide/native thiol, disulphide/total thiol and native/total thiol ratios than those of fertile men with varicocele and fertile controls. According to these results, the blood plasma of patients with varicocele contains excessive oxidative stress, even in men with normospermia, and therefore, thiol-disulphide homoeostasis may be useful as an oxidative stress marker in men with varicocele. © 2018 Blackwell Verlag GmbH.

  20. Optimization of chitosan gel preparation for supercritical impregnation of thymol

    Directory of Open Access Journals (Sweden)

    Milovanović Stoja L.


    Full Text Available The impregnation of differently prepared chitosan gels with thymol using supercritical carbon dioxide (scCO2 was studied in order to obtain new materials with added value without the use of organic solvents. The optimum conditions of supercritical impregnation (15 MPa, 35 °C and 24 h were defined based on previously investigated thymol solubility in scCO2. Cross-linkers formaldehyde and glutardialdehyde were used to prepare chitosan hydrogels. The obtained hydrogels of chitosan were converted in acetogels and then dried with air or by using scCO2 in order to obtain xerogels and aerogels. The best results, in terms of morphology and yield of impregnation with thymol, have been achieved for the aerogel of chitosan (11.30% which was obtained with cross-linker formaldehyde and dried with scCO2 at 15 MPa and 50 °C.

  1. Mn-Promoted Growth and Photoluminescence of Molybdenum Disulphide Monolayer

    Directory of Open Access Journals (Sweden)

    Shengzhong Jin


    Full Text Available Molybdenum disulphide (MoS2 monolayer is a two-dimensional semiconductor material with potential applications in nano electronic devices. However, it is still a challenge to reproducibly synthesize single layer MoS2 in high quality. Herein, we report the growth of monolayer of MoS2 on the SiO2/Si substrate with manganese heterogeneous nucleation. It was shown that the Mn promotes the growth of monolayer MoS2 via heterogeneous nucleation. The growth temperature range expanded two-fold, the nucleation density increased as well. The monolayer prepared in the presence of Mn exhibits a unique red emission peak at 732 nm at room temperature compared to the sample in the absence of Mn.

  2. Improved performance of electrodes based on carbonized olive stones/S composites by impregnating with mesoporous TiO2 for advanced Lisbnd S batteries (United States)

    Moreno, Noelia; Caballero, Álvaro; Morales, Julián; Rodríguez-Castellón, Enrique


    Carbons obtained from biomass have attracted a lot of attention for use as electrodes for Li-ion batteries. Less attention has been paid to their use in Lisbnd S batteries in spite of the higher energy densities. Here, we optimized the electrochemical properties of an activated carbon (OSAC) obtained from olive stones with the help of mesoporous TiO2. The OSAC@TiO2/S hybrid composite exhibited improved electrochemical performance compared with the OSAC/S composite. The presence of TiO2 increased the delivered capacity of the cell by more than 60%, and the rate capability was notably improved. The cell could operate at current densities of 3350 mA g-1 (2 C), releasing an average capacity of 500 mAh g-1 with a coulombic efficiency close to 100%. This improvement in the electrochemical performance is attributed to the sorbent properties of TiO2 towards Li polysulfides and its facility to insert Li, which enhances the electronic and ionic conductivity of the hybrid composite.

  3. Preparation of Surface Adsorbed and Impregnated Multi-walled Carbon Nanotube/Nylon-6 Nanofiber Composites and Investigation of their Gas Sensing Ability

    Directory of Open Access Journals (Sweden)

    Velmurugan Thavasi


    Full Text Available We have prepared electrospun Nylon-6 nanofibers via electrospinning, and adsorbed multi-walled carbon nanotubes (MWCNTs onto the surface of Nylon-6 fibers using Triton® X-100 to form a MWCNTs/Nylon-6 nanofiber composite. The dispersed MWCNTs have been found to be stable in hexafluoroisopropanol for several months without precipitation. A MWCNTs/Nylon-6 nanofiber composite based chemical sensor has demonstrated its responsiveness towards a wide range of solvent vapours at room temperature and only mg quantities of MWCNTs were expended. The large surface area and porous nature of the electrospun Nylon-6/MWCNT nanofibers facilitates greater analyte permeability. The experimental analysis has indicated that the dipole moment, functional group and vapour pressure of the analytes determine the magnitude of the responsiveness.

  4. Biodegradation of tetrahydrofuran by Pseudomonas oleovorans DT4 immobilized in calcium alginate beads impregnated with activated carbon fiber: mass transfer effect and continuous treatment. (United States)

    Chen, Dong-Zhi; Fang, Jun-Yi; Shao, Qian; Ye, Jie-Xu; Ouyang, Du-Juan; Chen, Jian-Meng


    A novel entrapment matrix, calcium alginate (CA) coupled with activated carbon fiber (ACF), was prepared to immobilize Pseudomonas oleovorans DT4 for degrading tetrahydrofuran (THF). The addition of 1.5% ACF increased the adsorption capacity of the immobilized bead, thus resulting in an enhanced average removal rate of 30.3mg/(Lh). The synergism between adsorption and biodegradation was observed in the hybrid CA-ACF beads instead of in the system comprising CA beads and freely suspended ACF. The effective diffusion coefficient of the CA-ACF bead was not significantly affected by bead size, but the bead's value of 1.14×10(-6)cm(2)/s (for the bead diameter of 0.4 cm) was larger than that of the CA bead by almost one order of magnitude based on the intraparticle diffusion-reaction kinetics analysis. Continuous treatment of the THF-containing wastewater was succeeded by CA-ACF immobilized cells in a packed-bed reactor for 54 d with a >90% removal efficiency. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Molybdenum disulphide and graphene quantum dots as electrode modifiers for laccase biosensor. (United States)

    Vasilescu, Ioana; Eremia, Sandra A V; Kusko, Mihaela; Radoi, Antonio; Vasile, Eugeniu; Radu, Gabriel-Lucian


    A nanocomposite formed from molybdenum disulphide (MoS2) and graphene quantum dots (GQDs) was proposed as a novel and suitable support for enzyme immobilisation displaying interesting electrochemical properties. The conductivity of the carbon based screen-printed electrodes was highly improved after modification with MoS2 nanoflakes and GQDs, the nanocomposite also providing compatible matrix for laccase immobilisation. The influence of different modification steps on the final electroanalytical performances of the modified electrode were evaluated by UV-vis absorption and fluorescence spectroscopy, scanning electron microscopy, transmission electron microscopy, X ray diffraction, electrochemical impedance spectroscopy and cyclic voltammetry. The developed laccase biosensor has responded efficiently to caffeic acid over a concentration range of 0.38-100µM, had a detection limit of 0.32µM and a sensitivity of 17.92nAµM(-1). The proposed analytical tool was successfully applied for the determination of total polyphenolic content from red wine samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Impregnation mode in wood plastic composite (United States)

    Mozaffar Husain, M.; Khan, Mubarak A.; Azam Ali, M.; Idriss Ali, K. M.; Mustafa, A. I.


    Bulk monomer MMA was impregnated into simul, a fuel wood of Bangladesh, under vacuum and under normal temperature and pressure conditions in order to compare the mode of impregnation and its effect on various characteristic parameters of wood plastic composites. Methanol (MeOH) was used as the swelling solvent with methylmethacrylate (MMA) at MMA: MeOH = 70:30, v/v. Impregnation of the bulk monomer was very high under vacuum compared to that at normal condition; but the difference of grafting of MMA to the wood cellulose under these two impregnating conditions was much lower as compared to that of the uptakes of impregnating solution MMA + MeOH under these two modes of impregnation. Incorporation of additives to MMA + MeOH has substantially enhanced grafting, tensile strength, bending strength and compression strength of thcomposite of such an extent that there is virtually very little difference between vacuum impregnation and normal impregnation. Considering the available data it is suggested that the impregnation under normal condition is preferable beacuse different substrates of various sizes and shapes can be suitably impregnated under normal condition while vacuum impregnation has several limitations in this respect.

  7. The change in serum Thiol/Disulphide homeostasis after transrectal ultrasound guided prostate biopsy. (United States)

    Tokgöz, Hüsnü; Taş, Selim; Giray, Özlem; Yalçınkaya, Soner; Tokgöz, Özlem; Koca, Cemile; Savaş, Murat; Erel, Özcan


    The aim of this prospective clinical study was to investigate variations in a novel oxidative stress marker (thiol/disulphide homeostasis) in men who underwent transrectal ultrasound guided prostate biopsy (TRUSB). A total of 22 men undergoing TRUSB of the prostate were enrolled in the study. Patients with abnormal digital rectal examination and/or total prostate specific antigen (PSA) over 4ng/mL underwent TRUSB with 12 cores. Serum samples were obtained before and just after the procedure to evaluate the possible changes in thiol/disulphide homeostasis. Mean age, total PSA and free PSA, prostate volume and histopathological data were also recorded. Mean age of the study population was 65.05±8.89 years. Significant decreases in native and total thiol levels were documented after the biopsy procedure. However, serum disulphide levels and disulphide/native thiol, disulphide/total thiol and native / total thiol ratios did not significantly change after TRUSB. No correlation was observed between oxidative parameters and total PSA and free PSA levels, prostate volume and histopathology of the prostate. However, mean patient age was significantly correlated with mean native and total thiol levels. Significant decreases in serum native and total thiol levels related to the prostate biopsy procedure suggest that TRUSB causes acute oxidative stress in the human body. Since our trial is the first in the current literature to investigate these oxidative stress markers in urology practice, additional studies are warranted. Copyright® by the International Brazilian Journal of Urology.

  8. [Construction and expression of disulphide stabilized anti-CD3/anti-Pgp diabody]. (United States)

    Su, Ye; Liu, Juanni; Gao, Yingdai; Qin, Li; Yang, Ming; Wang, Jinhong; Xu, Yuanfu; Shao, Xiaofeng; Ji, Qing; Xiong, Dongsheng; Yang, Chunzheng


    We constructed and expressed an anti-CD3/anti-Pgp (P-glycoprotein) diabody previously. However, the two chains of diabody are associated non-covalently, resulting in being capable of dissociating. The aim of this study is to enhance the stability of the diabody. We introduced cysteine residues into the CD3 or Pgp V-domain to covalently lock the two chains together. The disulphide crosslinked diabody were expressed by Escherichia coli (E. coli) 16C9 and purified by a cation exchange column and an anti-Etag affinity chromatography. The purified proteins were verified through SDS-PAGE. Flow cytometry (FCM) was used to analyse the binding properties, competitive binding capacity and stability in vitro. The dsPpg-diabody failed to form disulphide bond properly. The designed disulphide bridge between the different chains of dsCD3-diabody was formed correctly. FCM demonstrated the dsCD3-diabody has specific antigen binding activity, the same binding activity and competitive binding activity as its parent diabody. The dsCD3-diabody retained the full activity even after 72 h incubation at 37 degrees C in human serum, in contrast, the parent diabody began to lose activity after only 1 h and lose all its activity 24 hours later. The induced disulphide bond in the CD3 V-domain effectively enhanced the stability of anti-CD3/anti-Pgp diabody. The method of stabilizing a diabody by introducing a disulphide bond into is practical.

  9. Caracterização de um pré-impregnado aeronáutico por FT-IR e análise térmica Characterization of pre-impregnated of epoxy resin/carbon fiber

    Directory of Open Access Journals (Sweden)

    Vanesa C. G. M. Ferrari


    Full Text Available Este trabalho consiste na caracterização de um pré-impregnado ("prepreg" de resina epoxídica/fibra de carbono, usando-se espectroscopia no infravermelho com transformada de Fourier (FT-IR, análise termogravimétrica (TG, calorimetria exploratória diferencial (DSC e análise térmica dinâmico-mecânica (DMTA. A análise por FT-IR foi realizada nos modos de transmissão (pastilha de KBr, pirólise em bico de Bunsen e controlada e detecção fotoacústica (PAS. Os espectros de FT-IR de transmissão revelaram a presença de resina epoxídica, grupos ciano, amínicos e bisfenol A, que possibilitaram identificar o provável agente de cura:a cianoguanidina (ou dicianodiamida do sistema epoxídico. Os espectros de FT-IR/PAS permitiram acompanhar as alterações espectrométricas causadas pela cura. A análise térmica auxiliou na observação e compreensão dos eventos durante o processo de cura, etapas de gelificação e vitrificação, e da influência destas nas temperaturas de transição vítrea (Tg do material curado e na escolha do intervalo de temperatura de cura, que é um dos parâmetros mais importantes do processo produtivo.This work explores the characterization of pre-impregnated ("prepreg" materials made with an epoxy resin/carbon fiber, using FT-IR spectroscopy, thermogravimetry (TG, differential scanning calorimetry (DSC and dynamic mechanical thermal analysis (DMTA. FT-IR spectroscopy was used in the transmission mode (KBr pellets, pyrolysis without control and controlled pyrolysis and photoacoustic detection (FT-IR/PAS. The transmission FT-IR spectra revealed the presence of epoxy resin, cyano groups, amine and bisphenol A, which allowed us to identify the probable agent of cure: cyanoguanidine (or DCD. With FT-IR/PAS it was possible to monitor spectrometric changes caused by curing. The thermal analysis assisted in observing and understanding events during the curing process, including the gelation and vitrification steps. It

  10. The Effect of Water Repellent Surface Impregnation on Durability of Cement-Based Materials

    Directory of Open Access Journals (Sweden)

    Peng Zhang


    Full Text Available In many cases, service life of reinforced concrete structures is severely limited by chloride penetration until the steel reinforcement or by carbonation of the covercrete. Water repellent treatment on the surfaces of cement-based materials has often been considered to protect concrete from these deteriorations. In this paper, three types of water repellent agents have been applied on the surface of concrete specimens. Penetration profiles of silicon resin in treated concrete have been determined by FT-IR spectroscopy. Water capillary suction, chloride penetration, carbonation, and reinforcement corrosion in both surface impregnated and untreated specimens have been measured. Results indicate that surface impregnation reduced the coefficient of capillary suction of concrete substantially. An efficient chloride barrier can be established by deep impregnation. Water repellent surface impregnation by silanes also can make the process of carbonation action slow. In addition, it also has been concluded that surface impregnation can provide effective corrosion protection to reinforcing steel in concrete with migrating chloride. The improvement of durability and extension of service life for reinforced concrete structures, therefore, can be expected through the applications of appropriate water repellent surface impregnation.

  11. Impregnation quality of shredded semipreg after compression moulding (United States)

    Vincent, G.; Balakrishnan, V.; de Bruijn, T. A.; Wijskamp, S.; Abdul Rasheed, M. I.


    Manufacturing of thermoplastic composites (TPC) inherently generates scrap, mainly in the form of offcuts or rejected parts. The growth of TPC over recent decades has now reached a point where developing specific recycling solutions for TPC waste has become crucial. While looking at the various steps during which scrap is produced, the nesting of semipreg or prepreg appears to be critical. This work aims to develop a route for recycling semipreg offcuts, comprising shredding and compression moulding. This article focuses on an experimental study of the compression moulding step of carbon fibres reinforced PPS (C/PPS) to investigate the uniformity and impregnation quality of plates. These plates were realised in a picture frame while varying both the fibre volume content between 30% and 50% and the processing parameters. Visual inspection and cross-sectional microscopy were performed to assess the quality of each plate. As a first step, the influence of the type of added matrix (film, powder, pellets) and the type of pre-impregnation (film, powder) was studied. Stacking of polymer powder with shredded powder-coated semipreg gave the best impregnation quality. It was also shown that longer dwell time at melt leads to better consolidation quality. However, the difficulty in obtaining good impregnation comes from the disentangled shredded material, which is composed of three forms: semipreg flakes, dry bundles and pieces of matrix. When dry bundles reach the mould surfaces during the filling of the mould or when they are packed together, the consolidation cycle hardly impregnates them and they remain dry afterwards. Furthermore, large local variations of fibre fraction were noticed, resulting from a random mould filling. Therefore, the recycling solution for shredded semipreg is feasible when the fibre fraction is reduced but improvements on the part variability still have to be made.

  12. Deleting the first disulphide bond in an arenicin derivative enhances its expression in Pichia pastoris. (United States)

    Yang, N; Wang, X; Teng, D; Mao, R; Hao, Y; Feng, X; Wang, J


    The marine antimicrobial peptide NZ17074, a variant of arenicin-3 from Arenicola marina that has broad antimicrobial activity and high bioavailability, can be designed to treat bacterial and fungal diseases. To reduce the toxicity of NZ17074, N6 was designed by replacing a cysteine in positions 3 and 20 with alanine, fused to the C-terminus of the small ubiquitin-like modifier tag (SUMO), and expressed in yeast. SUMO-N6 yielded as much as 921 mg l-1 at 72 h after induction in a fermentor and increased 1·8-fold over SUMO-NZ17074. After cleavage with 30% formic acid and purification by a Sephadex G-25 column, 9·7 mg of the recombinant peptide N6 (rN6) was obtained from one-litre fermentation broth, increasing 1·4-fold over NZ17074. Compared to NZ17074, rN6 displayed almost identical antimicrobial activity with a minimal inhibitory concentration of 0·5, 0·25-0·5, 4, 0·25-16 and 16 μg ml-1 against Escherichia, Salmonella, Pseudomonas, Staphylococcus and Streptococcus strains. Our results indicate that the first disulphide bond, Cys3-Cys20, in NZ17074 is not necessary for antimicrobial activity and that its deletion might reduce toxicity to host cells. These findings may help design new antimicrobial peptides harbouring fewer disulphide bridges and may have more potent activity. Disulphide bond formation is an important step in the protein expression and can also influence protein secretion. A deletion of the first disulphide bond in NZ17074 increased the secreted level of target protein, and its antimicrobial activity was almost unaffected by the deletion of the first disulphide bond. The first disulphide bond in NZ17074 is favourable for correctly forming another disulphide bond during expression but not necessary for its activity. This may help design and produce a novel class of antimicrobial peptides harbouring fewer disulphide bridges to save the cost. © 2017 The Society for Applied Microbiology.

  13. Adsorption of mercury (II from liquid solutions using modified activated carbons

    Directory of Open Access Journals (Sweden)

    Hugo Soé Silva


    Full Text Available Mercury is one of the most toxic metals present in the environment. Adsorption has been proposed among the technologies for mercury abatement. Activated carbons are universal adsorbents which have been found to be a very effective alternative for mercury removal from water. The effectiveness with which a contaminant is adsorbed by the solid surface depends, among other factors, on the charge of the chemical species in which the contaminant is in solution and on the net charge of the adsorbent surface which depend on the pH of the adsorption system. In this work, activated carbon from carbonized eucalyptus wood was used as adsorbent. Two sulphurization treatments by impregnation with sulphuric acid and with carbon disulphide, have been carried out to improve the adsorption capacity for mercury entrapment. Batch adsorption tests at different temperatures and pH of the solution were carried out. The influence of the textural properties, surface chemistry and operation conditions on the adsorption capacity, is discussed.

  14. Disulphide production by Ero1a-PDI relay is rapid and effectively regulated

    DEFF Research Database (Denmark)

    Appenzeller-Herzog, Christian; Riemer, Jan; Zito, Ester


    The molecular networks that control endoplasmic reticulum (ER) redox conditions in mammalian cells are incompletely understood. Here, we show that after reductive challenge the ER steady-state disulphide content is restored on a time scale of seconds. Both the oxidase Ero1a and the oxidoreductase...

  15. A novel disulphide switch mechanism in Ero1 balances ER oxidation in human cells

    DEFF Research Database (Denmark)

    Appenzeller-Herzog, Christian; Riemer, Jan; Christensen, Brian


    Oxidative maturation of secretory and membrane proteins in the endoplasmic reticulum (ER) is powered by Ero1 oxidases. To prevent cellular hyperoxidation, Ero1 activity can be regulated by intramolecular disulphide switches. Here, we determine the redox-driven shutdown mechanism of Ero1 , the hou...

  16. Determination of thiol groups and disulphide bonds in wheat flour and dough

    NARCIS (Netherlands)

    Graveland, A.; Bosveld, P.; Marseille, J.P.


    A study was made of the conditions for determining all thiol (SH) groups and disulphide (S—S) bonds in wheat flour and dough. Thiol groups were determined by amperometric titration with Ag2SO4, the flour or dough which contains proteins and peptides being suspended in a solution of 6 m urea and 10−4

  17. Assignment of a single disulphide bridge in human alpha2-antiplasmin: implications for the structural and functional properties. (United States)

    Christensen, S; Valnickova, Z; Thogersen, I B; Olsen, E H; Enghild, J J


    Human alpha2-antiplasmin (alpha2AP) is a serpin involved in the regulation of blood coagulation. Most serpins, unlike smaller serine proteinase inhibitors, do not contain disulphide bridges. alpha2AP is an exception from this generalization and has previously been shown to contain four Cys residues organized into two disulphide bridges [Lijnen, Holmes, van Hoef, Wiman, Rodriguez and Collen (1987) Eur. J. Biochem. 166, 565-574]. However, we found that alpha2AP incorporates iodo[14C]acetic acid, suggesting that the protein contains reactive thiol groups. This observation prompted a re-examination of the state of the thiol groups, which revealed (i) a disulphide bridge between Cys43 and Cys116, (ii) that Cys76 is bound to a cysteinyl-glycine dipeptide, and (iii) and Cys125 exists as either a free thiol or in a mixed disulphide with another Cys residue. The disulphide identified between Cys43 and Cys116 appears to be conserved in orthologous proteins since the homologous Cys residues form disulphide bonds in bovine and possibly mouse alpha2AP. The conservation of this disulphide bridge suggests that it is important for functional aspects of alpha2AP. However, the structural and functional analysis described in this study does not support this conclusion. PMID:9169621

  18. Disulphide bridges of phospholipase C of Chlamydomonas reinhardtii modulates lipid interaction and dimer stability.

    Directory of Open Access Journals (Sweden)

    Mayanka Awasthi

    Full Text Available BACKGROUND: Phospholipase C (PLC is an enzyme that plays pivotal role in a number of signaling cascades. These are active in the plasma membrane and triggers cellular responses by catalyzing the hydrolysis of membrane phospholipids and thereby generating the secondary messengers. Phosphatidylinositol-PLC (PI-PLC specifically interacts with phosphoinositide and/or phosphoinositol and catalyzes specific cleavage of sn-3- phosphodiester bond. Several isoforms of PLC are known to form and function as dimer but very little is known about the molecular basis of the dimerization and its importance in the lipid interaction. PRINCIPAL FINDINGS: We herein report that, the disruption of disulphide bond of a novel PI-specific PLC of C. reinhardtii (CrPLC can modulate its interaction affinity with a set of phospholipids and also the stability of its dimer. CrPLC was found to form a mixture of higher oligomeric states with monomer and dimer as major species. Dimer adduct of CrPLC disappeared in the presence of DTT, which suggested the involvement of disulphide bond(s in CrPLC oligomerization. Dimer-monomer equilibrium studies with the isolated fractions of CrPLC monomer and dimer supported the involvement of covalent forces in the dimerization of CrPLC. A disulphide bridge was found to be responsible for the dimerization and Cys7 seems to be involved in the formation of the disulphide bond. This crucial disulphide bond also modulated the lipid affinity of CrPLC. Oligomers of CrPLC were also captured in in vivo condition. CrPLC was mainly found to be localized in the plasma membrane of the cell. The cell surface localization of CrPLC may have significant implication in the downstream regulatory function of CrPLC. SIGNIFICANCE: This study helps in establishing the role of CrPLC (or similar proteins in the quaternary structure of the molecule its affinities during lipid interactions.

  19. (PSLW) Activated Carbon

    African Journals Online (AJOL)



    Dec 2, 2017 ... ABSTRACT: Silver-impregnated carbon (SIC) and its precursor (un-impregnated) derived from an easily available low cost plant material Prosopis spicigera L. wood (PSLW) carbon was investigated for their ability to remove arsenic from aqueous solutions in batch and column experiments. Arsenic uptake ...

  20. The roles of protein disulphide isomerase family A, member 3 (ERp57) and surface thiol/disulphide exchange in human spermatozoa-zona pellucida binding. (United States)

    Wong, Chi-Wai; Lam, Kevin K W; Lee, Cheuk-Lun; Yeung, William S B; Zhao, Wei E; Ho, Pak-Chung; Ou, Jian-Ping; Chiu, Philip C N


    Are multimeric sperm plasma membrane protein complexes, ERp57 and sperm surface thiol content involved in human spermatozoa-zona pellucida (ZP) interaction? ERp57 is a component of a multimeric spermatozoa-ZP receptor complex involved in regulation of human spermatozoa-ZP binding via up-regulation of sperm surface thiol content. A spermatozoon acquires its fertilization capacity within the female reproductive tract by capacitation. Spermatozoa-ZP receptor is suggested to be a composite structure that is assembled into a functional complex during capacitation. Sperm surface thiol content is elevated during capacitation. ERp57 is a protein disulphide isomerase that modulates the thiol-disulphide status of proteins. The binding ability and components of protein complexes in extracted membrane protein fractions of spermatozoa were studied. The roles of capacitation, thiol-disulphide reagent treatments and ERp57 on sperm functions and sperm surface thiol content were assessed. Spermatozoa were obtained from semen samples from normozoospermic men. Human oocytes were obtained from an assisted reproduction programme. Blue native polyacrylamide gel electrophoresis, western ligand blotting and mass spectrometry were used to identify the components of solubilized ZP/ZP3-binding complexes. The localization and expression of sperm surface thiol and ERp57 were studied by immunostaining and sperm surface protein biotinylation followed by western blotting. Sperm functions were assessed by standard assays. Several ZP-binding complexes were isolated from the cell membrane of capacitated spermatozoa. ERp57 was a component of one of these complexes. Capacitation significantly increased the sperm surface thiol content, acrosomal thiol distribution and ERp57 expression on sperm surface. Sperm surface thiol and ERp57 immunoreactivity were localized to the acrosomal region of spermatozoa, a region responsible for ZP-binding. Up-regulation of the surface thiol content or ERp57 surface

  1. Thiol/disulphide exchange reaction: A key regulatory process in biological systems


    Chaudhuri, Amitabha


    Cysteine residues in proteins serve many important functions such as stabilizing and maintaining the three-dimensional conformation of many proteins(1), in enzyme catalysis, as a residue undergoing post-translational 2 and in the formation of DNA-binding modification domain of a class of transcriptional activators(3), It is also involved in biological redox coupling(4) and xenobiotic metabolism(5). Disulphide bonds formed by xenobiotic metabolism oxidation of cysteine residues have been used ...

  2. Role of the single disulphide bond of beta(2)-microglobulin in amyloidosis in vitro. (United States)

    Smith, D P; Radford, S E


    The aggregation of beta(2)-microglobulin (beta(2)m) into amyloid fibrils occurs in the condition known as dialysis-related amyloidosis (DRA). The protein has a beta-sandwich fold typical of the immunoglobulin family, which is stabilized by a highly conserved disulphide bond linking Cys25 and Cys80. Oxidized beta(2)m forms amyloid fibrils rapidly in vitro at acidic pH and high ionic strength. Here we investigate the role of the single disulphide bond of beta(2)m in amyloidosis in vitro. We show that reduction of the disulphide bond destabilizes the native protein such that non-native molecules are populated at neutral pH. These species are prone to oligomerization but do not form amyloid fibrils when incubated for up to 8 mo at pH 7.0 in 0.4 M NaCl. Over the pH range 4.0-1.5 in the presence of 0.4 M NaCl, however, amyloid fibrils of reduced beta(2)m are formed. These fibrils are approximately 10 nm wide, but are shorter and assemble more rapidly than those produced from the oxidized protein. These data show that population of non-native conformers of beta(2)m at neutral pH by reduction of its single disulphide bond is not sufficient for amyloid formation. Instead, association of one or more specific partially unfolded molecules formed at acid pH are necessary for the formation of beta(2)m amyloid in vitro. Further experiments will now be needed to determine the role of different oligomeric species of beta(2)m in the toxicity of the protein in vivo.

  3. Engineering and introduction of de novo disulphide bridges in organophosphorus hydrolase enzyme for thermostability improvement. (United States)

    Farnoosh, Gholamreza; Khajeh, Khosro; Latifi, Ali Mohammad; Aghamollaei, Hossein


    The organophosphorus hydrolase (OPH) has been used to degrade organophosphorus chemicals, as one of the most frequently used decontamination methods. Under chemical and thermal denaturing conditions, the enzyme has been shown to unfold. To utilize this enzyme in various applications, the thermal stability is of importance. The engineering of de novo disulphide bridges has been explored as a means to increase the thermal stability of enzymes in the rational method of protein engineering. In this study, Disulphide by Design software, homology modelling and molecular dynamics simulations were used to select appropriate amino acid pairs for the introduction of disulphide bridge to improve protein thermostability. The thermostability of the wild-type and three selected mutant enzymes were evaluated by half-life, delta G inactivation (ΔGi) and structural studies (fluorescence and far-UV CD analysis). Data analysis showed that half-life of A204C/T234C and T128C/E153C mutants were increased up to 4 and 24 min, respectively; however, for the G74C/A78C mutant, the half-life was decreased up to 9 min. For the T128C/E124C mutant, both thermal stability and Catalytic efficiency (kcat) were also increased. The half-life and ΔGi results were correlated to the obtained information from structural studies by circular dichroism (CD) spectrometry and extrinsic fluorescence experiments; as rigidity increased in A204C/T2234C and T128C/E153C mutants, half-life and ΔGi also increased. For G74C/A78C mutant, these parameters decreased due to its higher flexibility. The results were submitted a strong evidence for the possibility to improve the thermostability of OPH enzyme by introducing a disulphide bridge after bioinformatics design, even though this design would not be always successful.

  4. Novel roles for protein disulphide isomerase in disease states: a double edged sword?

    Directory of Open Access Journals (Sweden)

    Sonam eParakh


    Full Text Available Protein disulphide isomerase (PDI is a multifunctional redox chaperone of the endoplasmic reticulum (ER. Since it was first discovered 40 years ago the functions ascribed to PDI have evolved significantly and recent studies have recognized its distinct functions, with adverse as well as protective effects in disease. Furthermore, post translational modifications of PDI abrogate its normal functional roles in specific disease states. This review focusses on recent studies that have identified novel functions for PDI relevant to specific diseases.

  5. Impregnation of leather during "freeze-drying"

    DEFF Research Database (Denmark)

    Storch, Mikkel; Vestergaard Poulsen Sommer, Dorte; Hovmand, Ida


    Freeze-drying is a recognized method for the preservation of waterlogged objects. Naturally, freeze-drying has also been used for waterlogged archaeological leather often after treatment with Na2.EDTA and impregnation with PEG; but the treated leather sometimes suffers from “excessive drying......” becoming too stiff and brittle. The aim of this study was to examine the effect of a conventional freeze-drying method against an alternative freeze-drying method that preserves the natural moisture content of the leather. Both new and archaeological waterlogged leather were included in the study...... and the leather samples were treated in one of four ways: pre-treatment with Na2EDTA, impregnation with PEG 400, pre-treatment with Na2EDTA followed by impregnation with PEG 400 as well as no treatment. After the treatments, the leather samples were freeze-dried either by the conventional or by the alternative...

  6. Study on pyrolysis characteristics of lignocellulosic biomass impregnated with ammonia source. (United States)

    Li, Kai; Zhu, Changpeng; Zhang, Liqiang; Zhu, Xifeng


    The current study presents the pyrolysis characteristics of rice husk impregnated with different kinds of ammonia source (ammonium acetate, urea, ammonium sulfate and ammonium dihydrogen phosphate) in a fixed bed reactor. The introduction of ammonia source in pyrolysis process achieved the conversation from carbonyl compounds to nitrogenous heterocyclic compounds. The liquid product of urea-impregnated biomass has higher content of nitrogenous heterocyclic compounds (8.35%) and phenols (30.4%). For ammonium sulfate and ammonium dihydrogen phosphate-impregnated biomass, the quantity of compounds in liquid products reduces remarkably, and the gas products are rich in CO and H2. All the solid products of pyrolysis have great potential application in biochar-based fertilizer and activated carbon for their high N content. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Supercritical impregnation of cinnamaldehyde into polylactic acid as a route to develop antibacterial food packaging materials. (United States)

    Villegas, Carolina; Torres, Alejandra; Rios, Mauricio; Rojas, Adrián; Romero, Julio; de Dicastillo, Carol López; Valenzuela, Ximena; Galotto, María José; Guarda, Abel


    Supercritical impregnation was used to incorporate a natural compound with antibacterial activity into biopolymer-based films to develop active food packaging materials. Impregnation tests were carried out under two pressure conditions (9 and 12MPa), and three depressurization rates (0.1, 1 and 10MPamin(-1)) in a high-pressure cell at a constant temperature equal to 40°C. Cinnamaldehyde (Ci), a natural compound with proven antimicrobial activity, was successfully incorporated into poly(lactic acid) films (PLA) using supercritical carbon dioxide (scCO2), with impregnation yields ranging from 8 to 13% w/w. Higher pressure and slower depressurization rate seem to favor the Ci impregnation. The incorporation of Ci improved thermal, structural and mechanical properties of the PLA films. Impregnated films were more flexible, less brittle and more resistant materials than neat PLA films. The tested samples showed strong antibacterial activity against the selected microorganisms. In summary, this study provides an innovative route to the development of antibacterial biodegradable materials, which could be used in a wide range of applications of active food packaging. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Drug smuggling using clothing impregnated with cocaine. (United States)

    McDermott, Seán D; Power, John D


    A case study is presented where a woman travelling from South America to the Republic of Ireland was detained at Dublin Airport and articles of clothing she had in her luggage were found to be impregnated with cocaine. The study shows that the amount of powder recovered from the garments was approximately 14% of the total weight of the garments. The cocaine was in the form of cocaine hydrochloride and the purity was approximately 80%. An examination of the garments under filtered light highlighted the areas exposed to cocaine and indicated that the method of impregnation was by pouring liquid containing cocaine onto the clothing.

  9. Combustion properties of wood impregnated with commercial ...

    African Journals Online (AJOL)

    The objective of this study was to determine some combustion properties of Calabrian pine (Pinus brutia Ten.) wood specimens impregnated with aqueous solutions of commercial fertilizers. Ammonium sulphate (AS) and diammonium phosphate (DAP) were used as commercial fertilizers. Diammonium phosphate and ...

  10. Flammability studies of impregnated paper sheets (United States)

    Ivan Simkovic; Anne Fuller; Robert White


    Paper sheets impregnated with flame retardants made from agricultural residues and other additives were studied with the cone calorimeter. The use of sugar beet ethanol eluent (SBE), CaCl2, and ZnCl2 lowered the peak rate of heat release (PRHR) the most in comparison to water treated material. The average effective heat of...

  11. Mutation of yeast Eug1p CXXS active sites to CXXC results in a dramatic increase in protein disulphide isomerase activity

    DEFF Research Database (Denmark)

    Nørgaard, P; Winther, Jakob R.


    Protein disulphide isomerase (PDI) is an essential protein which is localized to the endoplasmic reticulum of eukaryotic cells. It catalyses the formation and isomerization of disulphide bonds during the folding of secretory proteins. PDI is composed of domains with structural homology to thiored...

  12. Graded Density Carbon Bonded Carbon Fiber (CBCF) Preforms for Lightweight Ablative Thermal Protection Systems (TPS) Project (United States)

    National Aeronautics and Space Administration — FMI currently manufactures Phenolic Impregnated Carbon Ablator (PICA) material for Thermal Protection Systems (TPS) systems, such as the Stardust Sample Return...

  13. Graded Density Carbon Bonded Carbon Fiber (CBCF) Preforms for Lightweight Ablative Thermal Protection Systems (TPS) Project (United States)

    National Aeronautics and Space Administration — FMI has developed graded density CBCF preforms for graded density phenolic impregnated carbon ablator (PICA) material to meet NASA's future exploration mission...

  14. Inorganic Nanoparticle-Modified Poly(Phenylene Sulphide/ Carbon Fiber Laminates: Thermomechanical Behaviour

    Directory of Open Access Journals (Sweden)

    Ana M. Díez-Pascual


    Full Text Available Carbon fiber (CF-reinforced high-temperature thermoplastics such as poly(phenylene sulphide (PPS are widely used in structural composites for aerospace and automotive applications. The porosity of CF-reinforced polymers is a very important topic for practical applications since there is a direct correlation between void content and mechanical properties. In this study, inorganic fullerene-like tungsten disulphide (IF-WS2 lubricant nanoparticles were used to manufacture PPS/IF-WS2/CF laminates via melt-blending and hot-press processing, and the effect of IF-WS2 loading on the quality, thermal and mechanical behaviour of the hybrid composites was investigated. The addition of IF-WS2 improved fiber impregnation, resulting in lower degree of porosity and increased delamination resistance, compression and flexural properties; their reinforcement effect was greater at temperatures above the glass transition (Tg. IF-WS2 contents higher than 0.5 wt % increased Tg and the heat deflection temperature while reduced the coefficient of thermal expansion. The multiscale laminates exhibited higher ignition point and notably reduced peak heat release rate compared to PPS/CF. The coexistence of micro- and nano-scale fillers resulted in synergistic effects that enhanced the stiffness, strength, thermal conductivity and flame retardancy of the matrix. The results presented herein demonstrate that the IF-WS2 are very promising nanofillers to improve the thermomechanical properties of conventional thermoplastic/CF composites.

  15. Inorganic Nanoparticle-Modified Poly(Phenylene Sulphide)/Carbon Fiber Laminates: Thermomechanical Behaviour (United States)

    Díez-Pascual, Ana M.; Naffakh, Mohammed


    Carbon fiber (CF)-reinforced high-temperature thermoplastics such as poly(phenylene sulphide) (PPS) are widely used in structural composites for aerospace and automotive applications. The porosity of CF-reinforced polymers is a very important topic for practical applications since there is a direct correlation between void content and mechanical properties. In this study, inorganic fullerene-like tungsten disulphide (IF-WS2) lubricant nanoparticles were used to manufacture PPS/IF-WS2/CF laminates via melt-blending and hot-press processing, and the effect of IF-WS2 loading on the quality, thermal and mechanical behaviour of the hybrid composites was investigated. The addition of IF-WS2 improved fiber impregnation, resulting in lower degree of porosity and increased delamination resistance, compression and flexural properties; their reinforcement effect was greater at temperatures above the glass transition (Tg). IF-WS2 contents higher than 0.5 wt % increased Tg and the heat deflection temperature while reduced the coefficient of thermal expansion. The multiscale laminates exhibited higher ignition point and notably reduced peak heat release rate compared to PPS/CF. The coexistence of micro- and nano-scale fillers resulted in synergistic effects that enhanced the stiffness, strength, thermal conductivity and flame retardancy of the matrix. The results presented herein demonstrate that the IF-WS2 are very promising nanofillers to improve the thermomechanical properties of conventional thermoplastic/CF composites. PMID:28811429

  16. The unfolded protein response and the role of protein disulphide isomerase in neurodegeneration.

    Directory of Open Access Journals (Sweden)

    Emma ePerri


    Full Text Available The maintenance and regulation of proteostasis is a critical function for post-mitotic neurons and dysregulation of proteostasis is increasingly implicated in neurodegenerative diseases. Despite having different clinical manifestations, these disorders share similar pathology; an accumulation of misfolded proteins in neurons and subsequent disruption to cellular proteostasis. The endoplasmic reticulum (ER is an important component of proteostasis, and when the accumulation of misfolded proteins occurs within the ER, this disturbs ER homeostasis, giving rise to ER stress. This triggers the unfolded protein response (UPR, distinct signalling pathways that whilst initially protective, are pro-apoptotic if ER stress is prolonged. ER stress is increasingly implicated in neurodegenerative diseases, and emerging evidence highlights the complexity of the UPR in these disorders, with both protective and detrimental components being described. Protein Disulphide Isomerase (PDI is an ER chaperone induced during ER stress that is responsible for the formation of disulphide bonds in proteins. Whilst initially considered to be protective, recent studies have revealed unconventional roles for PDI in neurodegenerative diseases, distinct from its normal function in the UPR and the ER, although these mechanisms remain poorly defined. However specific aspects of PDI function may offer the potential to be exploited therapeutically in the future. This review will focus on the evidence linking ER stress and the UPR to neurodegenerative diseases, with particular emphasis on the emerging functions ascribed to PDI in these conditions.

  17. Swelling kinetics and impregnation of PLA with thymol under supercritical CO2 conditions

    Directory of Open Access Journals (Sweden)

    Milovanović Stoja L.


    Full Text Available The present work was aimed to study swelling kinetics of polylactic acid (PLA and its impregnation with thymol in supercritical carbon dioxide (scCO2 medium. The influences of temperature and soaking time on the swelling kinetics and impregnation yield of PLA cylindrical disc and film were investigated. Swelling experiments were performed in a high pressure view cell at 10 MPa and temperatures of 40°C, 60°C and 75°C for 2 to 24 h. On the basis of swelling kinetics, pressure of 10 MPa and temperature of 40°C were chosen for supercritical solvent impregnation (SSI of the PLA samples during 2 to24 h. The highest swelling extent was observed for the PLA monolith after 24 h treatment with pure scCO2 (7.5% and scCO2 with thymol (118.3%. It was shown that sufficiently high amount of thymol can be loaded into both PLA monolith and film using SSI after only 2 h (10.0% and 6.6%, respectively. Monolith and film of PLA impregnated with thymol could be suitable for active food packaging and sterile medical disposables.

  18. Multi-impregnating pitch-bonded Egyptian dolomite refractory brick for application in ladle furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Rabah, M.; Ewais, E.M.M. [CMRDI, Cairo (Egypt)


    A method of preparation of multi-impregnated pitch-bonded Egyptian dolomite refractory brick for ladle furnace is described. Brick samples were prepared from blend of calcined dolomite mineral and coal tar pitch. The blend was hot mixed and pressed under a compression force up to 151 MPa. Green bricks were baked for 2 h at temperatures up to 1000 {sup o}C. Voids in the baked bodies were filled with carbon by multiple impregnations using low-softening point coal tar pitch. Each impregnation step (30 min) was followed by calcination at 1000 degrees C. Brick samples containing 8-12 wt.% coal tar pitch binder and pressed under 108-151 MPa acquired quantify crushing strength. However, multi-impregnating favored the mechanical strength of the baked brick samples and improved their hydration resistance (>45 days). Dolomite brick samples containing 10 wt.% coal tar pitch and pressed at 108 MPa gave high hydration resistance (more than 60 days in normal condition) compared to the hydration resistance of the commercial bricks (30 days). The prepared brick samples have acceptable density, chemical stability, outstanding resistance and good mechanical properties would meet the requirements of Ladle furnace (LF) for steel making industry. In addition, estimation of production cost of the brick indicates it is competitive with the market price based on durability and service life time aspects.

  19. Resonance enhanced multiphoton ionisation (REMPI) and REMPI-photoelectron spectroscopy of carbonyl sulphide and carbon disulphide

    NARCIS (Netherlands)

    Morgan, R.A.; Buma, W.J.; Baldwin, M.A.; Ascenzi, D.; Orr-Ewing, A.J.; Ashfold, M.N.R.; de Milan, J.B.; Scheper, C.R.; de Lange, C.A.


    The results of recent mass-resolved resonance enhanced multiphoton ionisation (REMPI) and REMPI-photoelectron spectroscopy (PES) studies of the sixteen valence electron molecules OCS and CS2 are used to illustrate some of the many opportunities offered by (and a few of the possible limitations

  20. The reaction of carbon disulphide with α-haloketones and primary ...

    Indian Academy of Sciences (India)

    35. Ramazani A, Mahyari A T, Rouhani M and Rezaei A. 2009 Tetrahedron Lett. 50 5625. 36. Zeinali Nasrabadi F, Ramazani A and Ahmadi Y 2011. Mol. Divers. 15 791. 37. Ramazani A, Ahmadi Y and Zeinali Nasrabadi F 2011 Z. Naturforsch. 66b 184. 38. Ramazani A and Souldozi A 2009 Phosphorus Sulfur. Silicon Relat.

  1. Biomass derived Ni(OH)2@porous carbon/sulfur composites synthesized by a novel sulfur impregnation strategy based on supercritical CO2 technology for advanced Li-S batteries (United States)

    Xia, Yang; Zhong, Haoyue; Fang, Ruyi; Liang, Chu; Xiao, Zhen; Huang, Hui; Gan, Yongping; Zhang, Jun; Tao, Xinyong; Zhang, Wenkui


    The rational design and controllable synthesis of sulfur cathode with high sulfur content, superior structural stability and fascinating electrochemical properties is a vital step to realize the large-scale application of rechargeable lithium-sulfur (Li-S) batteries. However, the electric insulation of elemental sulfur and the high solubility of lithium polysulfides are two intractable obstacles to hinder the success of Li-S batteries. In order to overcome aforementioned issues, a novel strategy combined supercritical CO2 fluid technology and biotemplating method is developed to fabricate Ni(OH)2 modified porous carbon microspheres as sulfur hosts to ameliorate the electronic conductive of sulfur and enhance simultaneously the physical and chemical absorptions of polysulfides. This elaborately designed Ni(OH)2@PYC/S composite cathode exhibits high reversible discharge capacity (1335 mAh g-1 at 0.1 C), remarkable cyclic stability (602 mAh g-1 after 200 cycles at 0.2 C) and superior rate capability, which is much better than its PYC/S counterpart. These results clearly demonstrate that the advanced porous carbon with good conductivity and the polar Ni(OH)2 coating layer with strong trapping ability of polysulfides are responsible for the enhanced electrochemical performance.

  2. Tanalith E 3494 impregnated wood: Characterisation and thermal behaviour


    Helsen, L.; Hardy, An; Van Bael, Marlies; Mullens, Jules


    Nowadays Tanalith (R) E 3494 (which is a copper azole based preservative) is the most widely used alternative wood preservative across Europe. In the present paper Tanalith (R) E 3494 impregnated wood is characterised through Fourier transform infrared spectroscopy (FTIR), revealing that carboxylic groups, phenolic groups and aromatic esters are the most active binding sites of copper during impregnation. Furthermore, the thermal behaviour of the Tanalith (R) E 3494 solution, the impregnated ...

  3. Mechanisms of Neuroprotection by Protein Disulphide Isomerase in Amyotrophic Lateral Sclerosis

    Directory of Open Access Journals (Sweden)

    Adam K. Walker


    Full Text Available Amyotrophic lateral sclerosis (ALS is a devastating neurodegenerative disease characterised by the progressive loss of motor neurons, leading to paralysis and death within several years of onset. Although protein misfolding is a key feature of ALS, the upstream triggers of disease remain elusive. Recently, endoplasmic reticulum (ER stress was identified as an early and central feature in ALS disease models as well as in human patient tissues, indicating that ER stress could be an important process in disease pathogenesis. One important chaperone induced by ER stress is protein disulphide isomerase (PDI, which is both upregulated and posttranslationally inhibited by S-nitrosylation in ALS. In this paper, we present evidence from studies of genetics, model organisms, and patient tissues which indicate an active role for PDI and ER stress in ALS disease processes.

  4. A disulphide-linked heterodimer of TWIK-1 and TREK-1 mediates passive conductance in astrocytes. (United States)

    Hwang, Eun Mi; Kim, Eunju; Yarishkin, Oleg; Woo, Dong Ho; Han, Kyung-Seok; Park, Nammi; Bae, Yeonju; Woo, Junsung; Kim, Donggyu; Park, Myeongki; Lee, C Justin; Park, Jae-Yong


    TWIK-1 is a member of the two-pore domain K(+) (K2P) channel family that plays an essential part in the regulation of resting membrane potential and cellular excitability. The physiological role of TWIK-1 has remained enigmatic because functional expression of TWIK-1 channels is elusive. Here we report that native TWIK-1 forms a functional channel at the plasma membrane of astrocytes. A search for TWIK-1-binding proteins led to the identification of TREK-1, another member of the K2P family. The TWIK-1/TREK-1 heterodimeric channel is formed via a disulphide bridge between residue C69 in TWIK-1 and C93 in TREK-1. Gene silencing demonstrates that surface expression of TWIK-1 and TREK-1 are interdependent. TWIK-1/TREK-1 heterodimers mediate astrocytic passive conductance and cannabinoid-induced glutamate release from astrocytes. Our study sheds new light on the diversity of K2P channels.

  5. Solution and solid state conformational preferences of a family of cyclic disulphide bridged tetrapeptides. (United States)

    Berger, Nadja; Li, Fee; Mallick, Bert; Brüggemann, J Thomas; Sander, Wolfram; Merten, Christian


    A set of cyclic tetrapeptides of the general form cyclo (Boc-Cys-Pro-X-Cys-OMe) with X being L-/D-Ala, L-/D-Val, and L-/D-Trp was synthesized. These peptides serve as model systems for structure elucidation in solution and feature a variety of structural motifs - namely a β-turn with intramolecular hydrogen bonding interactions, cis/trans isomerism, and a disulphide bond. In this work, we performed a comprehensive structural analysis focussing on their β-turn conformational preferences using NMR, VCD, and Raman spectroscopy. Our results provide evidence for a strong influence of a single stereocenter on the structures of the peptides whereas solvent polarity does not significantly affect them. Additionally, the solid state conformational preferences were studied by crystal structure analysis. Overall, a general trend for the conformational preferences of this set of peptides can be concluded from the results of the complementary investigations. © 2016 Wiley Periodicals, Inc.

  6. Multilayer Impregnated Fibrous Thermal Insulation Tiles (United States)

    Tran, Huy K.; Rasky, Daniel J.; Szalai, Christine e.; Hsu, Ming-ta; Carroll, Joseph A.


    The term "secondary polymer layered impregnated tile" ("SPLIT") denotes a type of ablative composite-material thermal- insulation tiles having engineered, spatially non-uniform compositions. The term "secondary" refers to the fact that each tile contains at least two polymer layers wherein endothermic reactions absorb considerable amounts of heat, thereby helping to prevent overheating of an underlying structure. These tiles were invented to afford lighter-weight alternatives to the reusable thermal-insulation materials heretofore variously used or considered for use in protecting the space shuttles and other spacecraft from intense atmospheric-entry heating.

  7. Impregnation of bentonite with cellulose as adsorbent of congo red

    Directory of Open Access Journals (Sweden)

    Monica Theresa


    Full Text Available The process of bentonite impregnation with cellulose has been studied. Cellulose extracted from rubber wood and clay from natural bentonite was activated. The impregnation process is performed using thiourea as impregnant agent. The impregnation results were characterized by using FT-IR spectrophotometer then the material was used as congo red dye adsorbent. Factors affecting the adsorption process were studied by kinetic parameters and thermodynamic parameters. The FTIR results indicate the impregnation process was succesfully conducted the characterization by FTIR indicated resources of typical absorption of the hydroxyl (OH and vibrational (-CH vibration function groups as specific groups of cellulose Appearing at wave numbers 3464.15 cm-1 and 2368.59 cm-1 from impregnated material. Vibration Si-O-Si and Al-O-Si as bentonite-specific strands groups Appear at 1465.9 cm-1 and 609.51 cm-1 wavenumbers in the impregnated spectra. The adsorption thermodynamic study showed that the adsorption and adsorption capacity of the cellulose-impregnated bentonite adsorbent reached the optimum point at 50 ° C at 43.47 mol / g and energy of 11.62 kJ mol. The optimum enthalpy (ΔH of cellulose bentonite was 143.13 kJ/mol and the minimum entropy (ΔS at concentration of 40 mg/L was 0.207 kJ/mol. Keywords: Bentonite, cellulose, impregnation; adsorption; Congo red

  8. Wood construction and magnetic characteristics of impregnated type magnetic wood (United States)

    Oka, Hideo; Hojo, Atsushi; Seki, Kyoushiro; Takashiba, Toshio


    The results of experiments involving the AC and DC magnetic characteristics of impregnated type magnetic wood were studied by taking into consideration the wood construction and fiber direction. The experimental results show that the sufficient amount of impregnated magnetic fluid varies depending on the fiber direction and length, and the grain face of the wood material. The impregnated type magnetic wood sample that is fully impregnated by magnetic fluid has a 60% saturation magnetization compared to the saturation magnetization of magnetic fluid. Samples for which the wood fiber direction was the same as the direction of the magnetic path had a higher magnetization intensity and permeability.

  9. Comparison of the compressive strength of impregnated and nonimpregnated eucalyptus subjected to two different pressures and impregnation times

    Directory of Open Access Journals (Sweden)

    Waldemir Rodrigues


    Full Text Available The durability of wood is affected by several factors. For this reason, much research has been done on a variety of chemical compounds for impregnating wood, aimed at preserving it while simultaneously improving its properties. Recent studies of the properties of impregnated wood have demonstrated the possibility of substantially improving its mechanical characteristics. Thus, the purpose of this work was to compare the strength to parallel compression of wooden fibers (Eucalyptus grandis, both nonimpregnated and impregnated with a monocomponent resin, from the standpoint of pressure and impregnation time, aiming at its structural utilization. The results demonstrate that the compressive strength of impregnated test specimens is greater than that of nonimpregnated ones, indicating that monocomponent polyurethane resin can be considered suitable for impregnating wood, since it increases the compressive strength of eucalyptus.

  10. Impact of impregnation with boron compounds on combustion ...

    African Journals Online (AJOL)

    This study examined the impacts of varnishing after impregnation with boron compounds on combustion properties of oriental beech. The test samples prepared from oriental beech (Fagus orientalis Lipsky) wood were impregnated according to ASTM D 1413–76–99 with boric acid (Ba) or borax (Bx) using a vacuum ...

  11. Impact of impregnation with boron compounds on combustion ...

    African Journals Online (AJOL)



    Apr 11, 2011 ... This study examined the impacts of varnishing after impregnation with boron compounds on combustion properties of oriental beech. The test samples prepared from oriental beech (Fagus orientalis Lipsky) wood were impregnated according to ASTM D 1413–76–99 with boric acid (Ba) or borax (Bx) using ...

  12. Polymer-impregnated bridge slabs : performance over 10 years. (United States)


    This report presents the results of a study to evaluate the performance over a 10-year period of slabs that were impregnated to a depth of about 1 in with a monomer that was subsequently polymerized (shallow polymer impregnation). The slabs were used...

  13. Effects of impregnation with boron compounds on the surface ...

    African Journals Online (AJOL)

    African Journal of Environmental Science and Technology ... Consequently, impregnation of wood material with boron compounds (boric acid: 3.677 Mpa and borax : 3.732 Mpa) showed increasing impact on the surface adhesion ... Key words: Adhesion strength, impregnation, boric acid, borax, varnishes, finishing, wood.

  14. Resin impregnation of cellulose nanofibril films facilitated by water swelling (United States)

    Yan Qing; Ronald Sabo; Zhiyong Cai; Yiqiang Wu


    Flexible composite films were produced by impregnating aqueous phenol formaldehyde (PF) resin into water-swollen cellulose nanofibril (CNF) films. CNF films were prepared using a pressurized filtration method in combination with freeze drying. The freeze-dried films were swollen with water then impregnated with PF resin by soaking in aqueous resin solutions of varying...

  15. Studies of properties of rubber wood with impregnation of polymer

    Indian Academy of Sciences (India)

    Impregnation of rubber wood has been carried out under different conditions by using styrene as grafting monomer and glycidyl methacrylate (GMA) as crosslinker. Properties such as dimensional stability, water absorption, hardness, tensile strength, flexural strength, etc of the impregnated wood have been checked and ...

  16. Effects of impregnation with boron compounds on the surface ...

    African Journals Online (AJOL)

    Liebl.) which met the requirements of ASTM D 358 were impregnated according to ASTM D 1413 with boric acid (Ba) and borax (Bx) by vacuum technique. After impregnation, surfaces were coated with cellulosic, synthetic, polyurathane, water-based, acrylic and acid hardening varnishes in accordance with ASTM D 3023 ...

  17. High-yield exfoliation of tungsten disulphide nanosheets by rational mixing of low-boiling-point solvents (United States)

    Sajedi-Moghaddam, Ali; Saievar-Iranizad, Esmaiel


    Developing high-throughput, reliable, and facile approaches for producing atomically thin sheets of transition metal dichalcogenides is of great importance to pave the way for their use in real applications. Here, we report a highly promising route for exfoliating two-dimensional tungsten disulphide sheets by using binary combination of low-boiling-point solvents. Experimental results show significant dependence of exfoliation yield on the type of solvents as well as relative volume fraction of each solvent. The highest yield was found for appropriate combination of isopropanol/water (20 vol% isopropanol and 80 vol% water) which is approximately 7 times higher than that in pure isopropanol and 4 times higher than that in pure water. The dramatic increase in exfoliation yield can be attributed to perfect match between the surface tension of tungsten disulphide and binary solvent system. Furthermore, solvent molecular size also has a profound impact on the exfoliation efficiency, due to the steric repulsion.

  18. Plasma impregnation of wood with fire retardants (United States)

    Pabeliña, Karel G.; Lumban, Carmencita O.; Ramos, Henry J.


    The efficacy of chemical and plasma treatments with phosphate and boric compounds, and nitrogen as flame retardants on wood are compared in this study. The chemical treatment involved the conventional method of spraying the solution over the wood surface at atmospheric condition and chemical vapor deposition in a vacuum chamber. The plasma treatment utilized a dielectric barrier discharge ionizing and decomposing the flame retardants into innocuous simple compounds. Wood samples are immersed in either phosphoric acid, boric acid, hydrogen or nitrogen plasmas or a plasma admixture of two or three compounds at various concentrations and impregnated by the ionized chemical reactants. Chemical changes on the wood samples were analyzed by Fourier transform infrared spectroscopy (FTIR) while the thermal changes through thermo gravimetric analysis (TGA). Plasma-treated samples exhibit superior thermal stability and fire retardant properties in terms of highest onset temperature, temperature of maximum pyrolysis, highest residual char percentage and comparably low total percentage weight loss.

  19. Co-expression of sulphydryl oxidase and protein disulphide isomerase in Escherichia coli allows for production of soluble CRM197. (United States)

    Roth, R; van Zyl, P; Tsekoa, T; Stoychev, S; Mamputha, S; Buthelezi, S; Crampton, M


    To investigate the production of soluble cross-reacting material 197 (CRM197 ) in Escherichia coli, a safe and effective T-cell-dependent protein carrier for polysaccharides used in the manufacture and application of multivalent conjugate vaccines. The use of co-expression of a sulphydryl oxidase (SOX) and protein disulphide isomerase for the production of soluble CRM197 in E. coli is described. CRM197 contains two disulphide bonds, which are normally unable to form in the reducing environment of the E. coli cytoplasm. It was found that co-expression yielded soluble CRM197 , at a production rate ~10% of the production of insoluble CRM197 , in equivalent small-scale cultures. Structural analysis of the purified CRM197 compared to CRM197 commercially produced in cultures of recombinant Pseudomonas fluorescens indicated that the E. coli soluble protein compares favourably on all structural levels. SOX and protein disulphide isomerase are enzymes involved in the formation of intra-protein disulphide bonds, and can influence the tertiary structure of the protein being produced, resulting in increased solubility due to the correct folding of the protein. Their use enabled the production of soluble untagged CRM197 in E. coli, which was previously unachievable. Previous literature reports have shown that CRM197 can be expressed in E. coli, though only in an insoluble form, or in soluble form as a fusion protein. It is currently commercially produced in cultures of recombinant P. fluorescens. The use of a widely used, well-characterized expression host such as E. coli, rather than P. fluorescens broadens the applicability of the production technology, and the production system described here is worthy of further investigation for scaled up manufacture of CRM197 . © 2017 The Society for Applied Microbiology.

  20. Protein Disulphide Isomerases: emerging roles of PDI and ERp57 in the nervous system and as therapeutic targets for ALS. (United States)

    Perri, Emma; Parakh, Sonam; Atkin, Julie


    There is increasing evidence that endoplasmic reticulum (ER) chaperones Protein Disulphide Isomerase (PDI) and ERp57 (endoplasmic reticulum protein 57) are protective against neurodegenerative diseases related to protein misfolding, including Amyotrophic Lateral Sclerosis (ALS). PDI and ERp57 also possess disulphide interchange activity, in which protein disulphide bonds are oxidized, reduced and isomerized, to form their native conformation. Recently, missense and intronic variants of PDI and ERp57 were associated with ALS, implying that PDI proteins are relevant to ALS pathology. Areas covered: Here, we discuss possible implications of the PDI and ERp57 variants, as well as recent studies describing previously unrecognized roles for PDI and ERp57 in the nervous system. Therapeutics based on PDI may therefore be attractive candidates for ALS. However, in addition to its protective functions, aberrant, toxic roles for PDI have recently been described. These functions need to be fully characterized before effective therapeutic strategies can be designed. Expert opinion: These disease-associated variants of PDI and ERp57 provide additional evidence for an important role for PDI proteins in ALS. However, there are many questions remaining unanswered that need to be addressed before the potential of the PDI family in relation to ALS can be fully realized.

  1. A study of electron and thermal transport in layered titanium disulphide single crystals (United States)

    Suri, Dhavala; Siva, Vantari; Joshi, Shalikram; Senapati, Kartik; Sahoo, P. K.; Varma, Shikha; Patel, R. S.


    We present a detailed study of thermal and electrical transport behavior of single crystal titanium disulphide flakes, which belong to the two dimensional, transition metal dichalcogenide class of materials. In-plane Seebeck effect measurements revealed a typical metal-like linear temperature dependence in the range of 85–285 K. Electrical transport measurements with in-plane current geometry exhibited a nearly T 2 dependence of resistivity in the range of 42–300 K. However, transport measurements along the out-of-plane current geometry showed a transition in temperature dependence of resistivity from T 2 to T 5 beyond 200 K. Interestingly, Au ion-irradiated TiS2 samples showed a similar T 5 dependence of resistivity beyond 200 K, even in the current-in-plane geometry. Micro-Raman measurements were performed to study the phonon modes in both pristine and ion-irradiated TiS2 crystals.

  2. Noise-like pulse generation in an ytterbium-doped fiber laser using tungsten disulphide (United States)

    Zhang, Wenping; Song, Yanrong; Guoyu, Heyang; Xu, Runqin; Dong, Zikai; Li, Kexuan; Tian, Jinrong; Gong, Shuang


    We demonstrated the noise-like pulse (NLP) generation in an ytterbium-doped fiber (YDF) laser with tungsten disulphide (WS2). Stable fundamental mode locking and second-order harmonic mode locking were observed. The saturable absorber (SA) was a WS2-polyvinyl alcohol film. The modulation depth of the WS2 film was 2.4%, and the saturable optical intensity was 155 MW cm-2. Based on this SA, the fundamental NLP with a pulse width of 20 ns and repetition rate of 7 MHz were observed. The autocorrelation trace of output pulses had a coherent spike, which came from NLP. The average pulse width of the spike was 550 fs on the top of a broad pedestal. The second-order harmonic NLP had a spectral bandwidth of 1.3 nm and pulse width of 10 ns. With the pump power of 400 mW, the maximum output power was 22.2 mW. To the best of our knowledge, this is the first time a noise-like mode locking in an YDF laser based on WS2-SA in an all normal dispersion regime was obtained.

  3. Degradation of dimethyl disulphide in soil with or without biochar amendment. (United States)

    Han, Dawei; Yan, Dongdong; Cao, Aocheng; Fang, Wensheng; Liu, Pengfei; Li, Yuan; Ouyang, Canbin; Wang, Qiuxia


    Dimethyl disulphide (DMDS) is a new and effective alternative to methyl bromide for soil fumigation. The effect of biochar on the fate of DMDS in soil is not fully understood. The objective of this study was to determine the degradation kinetics of DMDS in different soils and evaluate the effect of biochar amendment on DMDS degradation using incubation experiments. The degradation half-life of DMDS was between 1.05 and 6.66 days under non-sterile conditions, and 12.63 to 22.67 days under sterile conditions in five types of soil. Seven out of the eight tested biochar amendments (BC-2 to BC-8) delayed the degradation of DMDS in soil, increasing the half-life of DMDS in Fangshan soil from 1.05 to 1.16-5.87 days following amendment with 1% (w/w) biochar. The degradation rate of DMDS in Fangshan soil accelerated as the amendment rate of BC-1 increased, and decreased as the amendment rate of BC-7 increased. Biodegradation is an important degradation route for DMDS in soil, and DMDS degraded faster in alkaline soil. The effects of biochar amendments on DMDS degradation in soil are determined by complex multiple factors (such as surface area, pH and physicochemical composition), rather than by any single property of biochar. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  4. Tungsten disulphide for ultrashort pulse generation in all-fiber lasers. (United States)

    Liu, Wenjun; Pang, Lihui; Han, Hainian; Bi, Ke; Lei, Ming; Wei, Zhiyi


    Tungsten disulphide (WS2), which exhibits excellent saturable absorption properties, has attracted much attention in the applications of photonic devices. In this paper, WS2 is applied for the preparation of a saturable absorber (SA). Using the pulsed laser deposition (PLD) method, WS2 is deposited on the side surface of the tapered fiber. In order to obtain larger non-linearity of the SAs with evanescent wave interaction, the tapered fiber had a smaller waist diameter and longer fused zone. Gold film was deposited on the fiber-taper WS2 SAs to improve their reliability and avoid oxidation and corrosion. Employing the balanced twin-detector method, the modulation depth of the fiber-taper WS2 SAs was measured to be 17.2%. With the fiber-taper WS2 SA, a generated pulse with 246 fs duration and a 57 nm bandwidth was obtained at 1561 nm. The electrical signal to noise ratio was better than 92 dB. To our knowledge, the pulse duration was the shortest among the reported all-fiber lasers with transition metal dichalcogenide (TMD) SAs. These results indicate that fiber-taper WS2 SAs with smaller waist diameter and longer fused zone are promising photonic devices for ultrashort pulse generation in all-fiber lasers.

  5. High-throughput expression of animal venom toxins in Escherichia coli to generate a large library of oxidized disulphide-reticulated peptides for drug discovery. (United States)

    Turchetto, Jeremy; Sequeira, Ana Filipa; Ramond, Laurie; Peysson, Fanny; Brás, Joana L A; Saez, Natalie J; Duhoo, Yoan; Blémont, Marilyne; Guerreiro, Catarina I P D; Quinton, Loic; De Pauw, Edwin; Gilles, Nicolas; Darbon, Hervé; Fontes, Carlos M G A; Vincentelli, Renaud


    Animal venoms are complex molecular cocktails containing a wide range of biologically active disulphide-reticulated peptides that target, with high selectivity and efficacy, a variety of membrane receptors. Disulphide-reticulated peptides have evolved to display improved specificity, low immunogenicity and to show much higher resistance to degradation than linear peptides. These properties make venom peptides attractive candidates for drug development. However, recombinant expression of reticulated peptides containing disulphide bonds is challenging, especially when associated with the production of large libraries of bioactive molecules for drug screening. To date, as an alternative to artificial synthetic chemical libraries, no comprehensive recombinant libraries of natural venom peptides are accessible for high-throughput screening to identify novel therapeutics. In the accompanying paper an efficient system for the expression and purification of oxidized disulphide-reticulated venom peptides in Escherichia coli is described. Here we report the development of a high-throughput automated platform, that could be adapted to the production of other families, to generate the largest ever library of recombinant venom peptides. The peptides were produced in the periplasm of E. coli using redox-active DsbC as a fusion tag, thus allowing the efficient formation of correctly folded disulphide bridges. TEV protease was used to remove fusion tags and recover the animal venom peptides in the native state. Globally, within nine months, out of a total of 4992 synthetic genes encoding a representative diversity of venom peptides, a library containing 2736 recombinant disulphide-reticulated peptides was generated. The data revealed that the animal venom peptides produced in the bacterial host were natively folded and, thus, are putatively biologically active. Overall this study reveals that high-throughput expression of animal venom peptides in E. coli can generate large

  6. The cytotoxicity of garlic-related disulphides and thiosulfonates in WHCO1 oesophageal cancer cells is dependent on S-thiolation and not production of ROS. (United States)

    Smith, Muneerah; Hunter, Roger; Stellenboom, Nashia; Kusza, Daniel A; Parker, M Iqbal; Hammouda, Ahmed N H; Jackson, Graham; Kaschula, Catherine H


    Garlic has been used for centuries in folk medicine for its health promoting and cancer preventative properties. The bioactive principles in crushed garlic are allyl sulphur compounds which are proposed to chemically react through (i) protein S-thiolation and (ii) production of ROS. A collection of R-propyl disulphide and R-thiosulfonate compounds were synthesised to probe the importance of thiolysis and ROS generation in the cytotoxicity of garlic-related compounds in WHCO1 oesophageal cancer cells. A significant correlation (R(2)=0.78, Fcrit (7,1) α=0.005) was found between the cytotoxicity IC(50) and the leaving group pK(a) of the R-propyl disulphides and thiosulfonates, supporting a mechanism that relies on the thermodynamics of a mixed disulphide exchange reaction. Disulphide (1) and thiosulfonate (11) were further evaluated mechanistically and found to induce G(2)/M cell-cycle arrest and apoptosis, inhibit cell proliferation, and generate ROS. When the ROS produced by 1 and 11 were quenched with Trolox, ascorbic acid or N-acetyl cysteine (NAC), only NAC was found to counter the cytotoxicity of both compounds. However, NAC was found to chemically react with 11 through mixed disulphide formation, providing an explanation for this apparent inhibitory result. Cellular S-thiolation by garlic related disulphides appears to be the cause of cytotoxicity in WHCO1 cells. Generation of ROS appears to only play a secondary role. Our findings do not support ROS production causing the cytotoxicity of garlic-related disulphides in WHCO1 cells. Importantly, it was found that the popular ROS inhibitor NAC interferes with the assay. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Wood impregnation of yeast lees for winemaking. (United States)

    Palomero, Felipe; Bertani, Paolo; Fernández de Simón, Brígida; Cadahía, Estrella; Benito, Santiago; Morata, Antonio; Suárez-Lepe, José A


    This study develops a new method to produce more complex wines by means of an indirect diffusion of wood aromas from yeast cell-walls. An exogenous lyophilized biomass was macerated with an ethanol wood extract solution and subsequently dried. Different times were used for the adsorption of polyphenols and volatile compounds to the yeast cell-walls. The analysis of polyphenols and volatile compounds (by HPLC/DAD and GC-MS, respectively) demonstrate that the adsorption/diffusion of these compounds from the wood to the yeast takes place. Red wines were also aged with Saccharomyces cerevisiae lees that had been impregnated with wood aromas and subsequently dried. Four different types of wood were used: chestnut, cherry, acacia and oak. Large differences were observed between the woods studied with regards to their volatile and polyphenolic profiles. Sensory evaluations confirmed large differences even with short-term contact between the wines and the lees, showing that the method could be of interest for red wine making. In addition, the results demonstrate the potential of using woods other than oak in cooperage. Copyright © 2014 Elsevier Ltd. All rights reserved.





    The polymer matrix (PAD-400) was impregnated by diethyldithiophosphate and used for sorption of silver ions from solutions. The impregnated sorbents were characterized by FTIR, SEM and DTA data. It was established that silver ions have been sorbed from solutions with impregnated sorbents due to formation of the metal-impregnate surface complexes. The sorption process is described better with Freundlich equation.

  9. The effects of ozone on bacterial growth and thiol-disulphide homeostasis in vascular graft infection caused by MRSA in rats. (United States)

    Ozturk, Barcin; Kurtoglu, Tunay; Durmaz, Selim; Kozaci, Leyla Didem; Abacigil, Filiz; Ertugrul, Bulent; Erel, Ozcan


    To investigate the microbiological, inflammatory and oxidant effects of adjuvant ozone administration in experimental rat vascular graft infection model which has not been previously investigated. Forty adult Wistar rats were divided into Sham, Control, Vancomycin, Ozone, Vancomycin+Ozone groups. Grafts were inoculated with Methicillin-resistant Staphylococcus aureus (MRSA) strain and implanted subcutaneously. Rats were treated intraperitoneally with ozone and /or intramuscularly with vancomycin for 10 days. Grafts were evaluated by quantitative bacterial cultures. Blood samples were harvested for determination of thiol-disulphide and cytokine profiles. There was no significant difference in bacterial counts between Control and Ozone Groups. In the Ozone Group median colony count was significantly higher than the Vancomycin and Vancomycin+Ozone Groups. Total thiol and disulphide levels increased and disulphide/native thiol and disulphide/total thiol ratios decreased in Ozone Group significantly. Albumin levels decreased significantly in Vancomycin and Vancomycin+Ozone Groups compared to the Sham Group. IL-1 and TNF-alpha levels significantly increased in infected rats. Decreased levels of VEGF due to infection reversed by ozone therapy in control and vancomycin groups. We didn't observe any benefit of the agent on MRSA elimination in our model. Likewise, effects of ozone on thiol-disulphide homeostasis and inflammatory cytokines were contradictory.

  10. Al6061 Hybrid Metal Matrix Composite Reinforced with Alumina and Molybdenum Disulphide

    Directory of Open Access Journals (Sweden)

    G. Pitchayyapillai


    Full Text Available Aluminum Hybrid Reinforcement Technology is a response to the dynamic ever-increasing service requirement of industries such as transportation, aerospace, automobile, and marine, due to its attractive properties like high ductility, highly conductivity, light weight, and high strength to weight ratio. In this evolution, an attempt has been made to investigate the wear rate of Al6061 hybrid metal matrix composite reinforced with the hard ceramic alumina (4, 8, and 12 wt.% of Al2O3 and soft solid lubricant of molybdenum disulphide (2, 4, and 6 wt.% of MoS2 is fabricated by using stir casting method. The unlubricated pins on disc wear tests were conducted to examine the wear behaviour of Al6061/12 wt.% of Al2O3/MoS2 composites. The sliding wear tests were carried out at various loads of 15, 30, and 45 N, sliding velocity (1.25, 2.50, and 3.25 m/sec, and different MoS2 wt.% (2, 4, and 6 wt.%. In addition, the CNC turning experiments were conducted on Al6061/12 wt.% Al2O3/6 wt.% MoS2 using CNMG 120408 uncoated carbide cutting tool under cutting of 100, 150, and 200 m/min, feed of 0.1, 0.2, and 0.3 mm/rev, and depth of cut of 1, 1.5, and 2 mm.

  11. Morphology and thermal properties of biodegradable poly(hydroxybutyrate-co-hydroxyvalerate)/tungsten disulphide inorganic nanotube nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Silverman, Tyler [Escuela Técnica Superior de Ingenieros Industriales, Universidad Politécnica de Madrid (ETSII-UPM), José Gutiérrez Abascal 2, 28006 Madrid (Spain); Naffakh, Mohammed, E-mail: [Escuela Técnica Superior de Ingenieros Industriales, Universidad Politécnica de Madrid (ETSII-UPM), José Gutiérrez Abascal 2, 28006 Madrid (Spain); Marco, Carlos; Ellis, Gary [Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), Juan de la Cierva 3, 28006 Madrid (Spain)


    Promising biodegradable and renewable poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) nanocomposites based on tungsten disulphide inorganic nanotubes (INT-WS{sub 2}) were efficiently prepared by a simple solution blending method. The structure, morphology, thermal stability and crystallization behavior of the nanocomposites were investigated by ultra-high field-emission scanning electron microscope (FESEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS) and polarized optical microscopy (POM) techniques. As previously observed in poly(3-hydroxybutyrate) (PHB) hybrid systems, the dispersion, morphology and thermal properties of PHBV/INT-WS{sub 2} nanocomposites could be tuned by the introduction of small amounts of INT-WS{sub 2}. The results revealed that a good dispersion of INT-WS{sub 2} in the PHBV matrix influenced the morphology and non-isothermal crystallization behavior of PHBV that depends on both the INT-WS{sub 2} concentration and the cooling rate. A significant enhancement in thermal stability of PHBV and a highly efficient nucleating effect of the INT-WS{sub 2} comparable to specific nucleating agents or other nano-sized fillers was observed. These observations are of importance for extending the practical applications of these biopolymer nanocomposites towards eco-friendly (e.g. sustainable packaging) and biomedical (e.g. bone tissue engineering) applications. - Highlights: • Environmentally-friendly INT-WS{sub 2} is used to produce advanced PHBV NCPs. • Novel INT-WS{sub 2} improve the thermal stability of PHBV. • INT-WS{sub 2} is effective to accelerate the crystallization of PHBV. • Ring-banded spherulites of PHBV are observed at low INT-WS{sub 2} contents. • The benefits of using INTs compared to other nanoscale fillers are highlighted.

  12. A Model for Tow Impregnation and Consolidation for Partially Impregnated Thermoset Prepregs

    Energy Technology Data Exchange (ETDEWEB)

    John J. Gangloff Jr; Shatil Sinha; Suresh G. Advani


    The formation and transport of voids in composite materials remains a key research area in composite manufacturing science. Knowledge of how voids, resin, and fiber reinforcement propagate throughout a composite material continuum from green state to cured state during an automated tape layup process is key to minimizing defects induced by void-initiated stress concentrations under applied loads for a wide variety of composite applications. This paper focuses on modeling resin flow in a deforming fiber tow during an automated process of partially impregnated thermoset prepreg composite material tapes. In this work, a tow unit cell based model has been presented that determines the consolidation and impregnation of a thermoset prepreg tape under an input pressure profile. A parametric study has been performed to characterize the behavior of varying tow speed and compaction forces on the degree of consolidation. Results indicate that increased tow consolidation is achieved with slower tow speeds and higher compaction forces although the relationship is not linear. The overall modeling of this project is motivated to address optimization of the 'green state' composite properties and processing parameters to reduce or eliminate 'cured state' defects, such as porosity and de-lamination. This work is partially funded by the Department of Energy under Award number DE-EE0001367.

  13. Fracture Resistance of Composite Fixed Partial Dentures Reinforced with Pre-impregnated and Non-impregnated Fibers

    Directory of Open Access Journals (Sweden)

    Ramin Mosharraf


    Full Text Available Background and aims. The mechanical properties of fiber-reinforced composite fixed partial dentures (FPDs are affected by fiber impregnation. The aim of this in vitro study was to compare the fracture resistance of composite fixed partial dentures reinforced with pre-impregnated and non-impregnated fibers. Materials and methods. Groups (n=5 of three-unit fiber-reinforced composite FPDs (23 mm in length from maxillary second premolar to maxillary second molar were fabricated on two abutments with pontic width of 12 mm. One group was fabricated as the control group with composite (Gradia and the other two groups were fabricated with composite (Gradia reinforced with pre-impregnated fiber (Fibrex ribbon and non-impregnated fiber (Fiber braid, respectively. The specimens were stored in distilled water for one week at 37°C and then tested in a universal testing machine by means of a three-point bending test. Statistical analysis consisted of one-way ANOVA and a post hoc Scheffé’s test for the test groups (α=0.05. Results. Fracture resistance (N differed significantly between the control group and the other two groups (P<0.001, but there were no statistically significant differences between the pre-impregnated and non-impregnated groups (P=0.565. The degree of deflection measured (mm did not differ significantly between the three groups (P=0.397, yet the mean deflection measured in pre-impregnated group was twice as that in the other two groups. Conclusion. Reinforcement of composite with fiber might considerably increase the fracture resistance of FPDs; however, the type of the fiber used resulted in no significant difference in fracture resistance of FPD specimens.

  14. Disulphide trapping of the GABAA receptor reveals the importance of the coupling interface in the action of benzodiazepines (United States)

    Hanson, Susan M; Czajkowski, Cynthia


    BACKGROUND AND SIGNIFICANCE Although the functional effects of benzodiazepines (BZDs) on GABAA receptors have been well characterized, the structural mechanism by which these modulators alter activation of the receptor by GABA is still undefined. EXPERIMENTAL APPROACH We used disulphide trapping between engineered cysteines to probe BZD-induced conformational changes within the γ2 subunit and at the α1/γ2 coupling interface (Loops 2, 7 and 9) of α1β2γ2 GABAA receptors. KEY RESULTS Crosslinking γ2Loop 9 to γ2β-strand 9 (via γ2S195C/F203C and γ2S187C/L206C) significantly decreased maximum potentiation by flurazepam, suggesting that modulation of GABA-induced current (IGABA) by flurazepam involves movements of γ2Loop 9 relative to γ2β-strand 9. In contrast, tethering γ2β-strand 9 to the γ2 pre-M1 region (via γ2S202C/S230C) significantly enhanced potentiation by both flurazepam and zolpidem, indicating γ2S202C/S230C trapped the receptor in a more favourable conformation for positive modulation by BZDs. Intersubunit disulphide bonds formed at the α/γ coupling interface between α1Loop 2 and γ2Loop 9 (α1D56C/γ2L198C) prevented flurazepam and zolpidem from efficiently modulating IGABA. Disulphide trapping α1Loop 2 (α1D56C) to γ2β-strand 1 (γ2P64C) decreased maximal IGABA as well as flurazepam potentiation. None of the disulphide bonds affected the ability of the negative modulator, 3-carbomethoxy-4-ethyl-6,7-dimethoxy-β-carboline (DMCM), to inhibit IGABA. CONCLUSIONS AND IMPLICATIONS Positive modulation of GABAA receptors by BZDs requires reorganization of the loops in the α1/γ2 coupling interface. BZD-induced movements at the α/γ coupling interface likely synergize with rearrangements induced by GABA binding at the β/α subunit interfaces to enhance channel activation by GABA. PMID:20942818

  15. Effects of a dehydrating agent on the carbonization of wood (United States)

    Kim, Dae-Young; Kang, Kyu-Young


    The carbonization of sulfuric acid impregnated wood meal and wood block was studied by using thermogravimetry (TG) and scanning electron microscopy (SEM). The samples were carbonized up to 800 °C at a heating rate of 10 °C/min under nitrogen. Improvement of the char yield was observed to be similar to the case of cellulose. Without sulfuric acid impregnation, the wood blocks significantly shrank on carbonization, and the shrinkage was strongly anisotropic. The degree of shrinkage was in the order of tangential > radial > longitudinal directions. Sulfuric acid impregnated wood blocks largely retained the size and cell wall morphology. The nitrogen adsorption surface area of wood meal char prepared with sulfuric acid impregnation was greater than that of the control. Thus, the carbonization of wood with sulfuric acid impregnation was found to be advantageous in mass yield and preservation of size and shape.

  16. Toluene removal by sequential adsorption-plasma catalytic process: Effects of Ag and Mn impregnation sequence on Ag-Mn/γ-Al2O3. (United States)

    Qin, Caihong; Huang, Xuemin; Dang, Xiaoqing; Huang, Jiayu; Teng, Jingjing; Kang, Zhongli


    A series of Ag-Mn/γ-Al2O3 were prepared under different Ag/Mn impregnation sequence and tested in the sequential adsorption-plasma catalytic removal of toluene. When Mn was impregnated first, the resulting catalyst, Ag-Mn(F)/γ-Al2O3, had longer breakthrough time, gave less emission of toluene, had higher CO2 selectivity, and had better carbon balance and COx yield compared to catalysts prepared via other impregnation sequences. After 120 min of NTP treatment, the carbon balance of Ag-Mn(F)/γ-Al2O3 was 91%, with 87% as COx contributions. A Brunauer-Emmett-Teller (BET) analysis and X-ray photoelectron spectroscopy (XPS) results show that, the impregnation sequence impacts the BET surface area and the ratio and existing state of Ag on the surface of the catalysts. The longer breakthrough time when using Ag-Mn(F)/γ-Al2O3 as catalyst is attributed to the large amount of Ag(+) on the surface. Ag(+) is a new active site for toluene adsorption. When Ag was impregnated first (Ag(F)-Mn/γ-Al2O3) or Ag and Mn co-impregnated (Ag-Mn-C/γ-Al2O3), the predominant specie was Ag(+). Both Ag(0) and Ag(+) species were detected on Ag-Mn(F)/γ-Al2O3. Ag(0) cooperation with MnOx may promote the migration of surface active oxygen. This would facilitate the oxidation of adsorbed toluene with CC bond already weakened by Ag(+) and would result in higher CO2 selectivity and better carbon balance as seen in the Ag-Mn(F)/γ-Al2O3 system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Identification of thioredoxin h-reducible disulphides in proteornes by differential labelling of cysteines: Insight into recognition and regulation of proteins in barley seeds by thioredoxin h

    DEFF Research Database (Denmark)

    Maeda, Kenji; Finnie, Christine; Svensson, Birte


    , thioredoxin h-reducible disulphide bonds in individual target proteins are identified using a novel strategy based on differential alkylation of cysteine thiol groups by iodoacetamide and 4-vinylpyridine. This method enables the accessible cysteine side chains in the thiol form (carbamidomethylated...... alpha-amylase/subtilisin inhibitor (BASI) by barley thioredoxin h isoform 1 was analysed. Furthermore, the method was coupled with two-dimensional electrophoresis for convenient thioredoxin h-reducible disulphide identification in barley seed extracts without the need for protein purification...

  18. Degradation Free Vacuum Epoxy Impregnated short REBCO Undulator Magnets (United States)

    Kesgin, I.; Hasse, Q.; Ivanyushenkov, Y.; Welp, U.


    The source of high–brilliance, hard x-ray radiation in light sources and free electron lasers are undulator insertion devices. Recently, REBCO-based superconductors have been demonstrated to be a potential candidate to enhance the performance of the undulator insertion devices. Epoxy impregnation remained as one of the steps which is crucial to fully realize this technology. Epoxy impregnation of magnets is required because it prevents the motion of the wire and provides conduction cooling to the winding layers. Up until now, most of the impregnated REBCO coils/magnets showed some degree of degradation after cold cycles. We developed a vacuum impregnation technique that does not degrade the performance of the short REBCO prototype undulator magnets after cold cycles. The results showed that in order to prevent degradation, a bumper layer between the magnet winding stacks and the epoxy/powder mixture is required. Microstructure images of vacuum impregnated coil packs showed homogenously-spaced REBCO winding layers and very thin epoxy fillings between the layers, which is important for the overall performance of the device.

  19. Iron-impregnated biochars as effective phosphate sorption materials. (United States)

    Micháleková-Richveisová, Barbora; Frišták, Vladimír; Pipíška, Martin; Ďuriška, Libor; Moreno-Jimenez, Eduardo; Soja, Gerhard


    A new post-treatment method was applied for improving the sorption efficiency of biochar-based sorbents for anionic forms of phosphorus. The Fe-impregnation through direct hydrolysis of Fe(NO3)3 was used to produce impregnated corn cob- (IBC A), garden wood waste- (IBC B), and wood chip-derived biochars (IBC C). The qualitative and quantitative effects of impregnation process on biochars were confirmed by SEM-EDX, FTIR, and ICP-MS. The analyses revealed increased concentrations of N and thus potential NO3(-) participation in the phosphate sorption process. Biochar surface area showed a significant decrease after the impregnation process due to the filling of micro- and mesopores with Fe maximum sorption capacity (Q max) increased by a factor of 12-50. The sorption processes of phosphates by IBC A, IBC B, and IBC C were dependent on pH, initial concentration, and time. Speciation analysis and pH-study confirmed the range of pH 4.5-5.5 as optimum values at which most of phosphorus is present in form of mononuclear H2PO4(-). Batch sorption experiments showed a significant increase in the sorption capacity for phosphates by Fe impregnation of biochar as well as effectiveness and stability of this treatment. These findings indicate an option for utilizing engineered biochars as tools for the recovery of phosphorus from the aquatic environment.

  20. Atomistic Simulations of Defect Nucleation and Intralayer Fracture in Molybdenum Disulphide During Nanoindentation (United States)

    Stewart, James A., Jr.

    Molybdenum disulphide (MoS2) is a layered, hexagonal crystal that has a very low coefficient of friction. Due to this low coefficient of friction, MoS2 has become a well-known solid lubricant and liquid lubricant additive. As such, nanoparticles of MoS2 have been proposed as an additive to traditional liquid lubricants to provide frictional properties that are sensitive to different temperature and pressure regimes. However, to properly design these MoS2 nanoparticles to be sensitive to different temperature and pressure regimes, it is necessary to understand the mechanical response of crystalline MoS2 under mechanical loading. Specifically, the fundamental mechanism associated with the nucleation and interaction of defects as well as intralayer fracture. This thesis addressed the mechanical response of crystalline MoS2 via contact deformation (nanoindentation) simulations, which is representative of the loading conditions experienced by these nanoparticles during synthesis and application. There are two main tasks to this thesis. First, a Mo-S interatomic potential (a combination of the reactive empirical bond-order (REBO) interatomic potential and the Lennard-Jones 12-6 interatomic potential) that has been parameterized specifically to investigate the tribological properties of MoS2 was implemented into the classical molecular simulation package, LAMMPS, and refined to provide improved predictions for the mechanical properties of MoS 2 via molecular statics calculations. Second, using this newly implemented interatomic potential, molecular statics calculations were performed to investigate the mechanical response of MoS2 via nanoindentation with specific focus on the nucleation of defects. Nanoindentation force - displacement curves were compared to the Hertzian contact theory prediction. It was shown that MoS2 does not follow the Hertzian prediction due it anisotropic nature. In addition, it was shown that the initial sudden force drop event in the force

  1. Susceptibility towards intramolecular disulphide-bond formation affects conformational stability and folding of human basic fibroblast growth factor. (United States)

    Estapé, D; van den Heuvel, J; Rinas, U


    The conformational stability and the folding properties of the all-beta-type protein human basic fibroblast growth factor (hFGF-2) were studied by means of fluorescence spectroscopy. The results show that the instability of the biological activity of hFGF-2 is also reflected in a low conformational stability of the molecule. The reversibility of the unfolding and refolding process was established under reducing conditions. Determination of the free-energy of unfolding in the presence of reducing agents revealed that the conformational stability of hFGF-2 (DeltaGH2Oapp congruent with21 kJ. mol-1, 25 degreesC) is low compared with other globular proteins under physiological conditions (20-60 kJ.mol-1). However, the conformational stability of hFGF-2 is particularly low under non-reducing conditions. This instability is attributed to intramolecular disulphide-bond formation, rendering the molecule more susceptible to denaturant-induced unfolding. In addition, denaturant-induced unfolding of hFGF-2 renders the protein more susceptible to irreversible oxidative denaturation. Experimental evidence is provided that the irreversibility of the unfolding and refolding process in the absence of reducing agents is linked to the formation of an intramolecular disulphide bond involving cysteines 96 and 101. PMID:9761733

  2. The Role of S-Nitrosylation and S-Glutathionylation of Protein Disulphide Isomerase in Protein Misfolding and Neurodegeneration

    Directory of Open Access Journals (Sweden)

    M. Halloran


    Full Text Available Neurodegenerative diseases involve the progressive loss of neurons, and a pathological hallmark is the presence of abnormal inclusions containing misfolded proteins. Although the precise molecular mechanisms triggering neurodegeneration remain unclear, endoplasmic reticulum (ER stress, elevated oxidative and nitrosative stress, and protein misfolding are important features in pathogenesis. Protein disulphide isomerase (PDI is the prototype of a family of molecular chaperones and foldases upregulated during ER stress that are increasingly implicated in neurodegenerative diseases. PDI catalyzes the rearrangement and formation of disulphide bonds, thus facilitating protein folding, and in neurodegeneration may act to ameliorate the burden of protein misfolding. However, an aberrant posttranslational modification of PDI, S-nitrosylation, inhibits its protective function in these conditions. S-nitrosylation is a redox-mediated modification that regulates protein function by covalent addition of nitric oxide- (NO- containing groups to cysteine residues. Here, we discuss the evidence for abnormal S-nitrosylation of PDI (SNO-PDI in neurodegeneration and how this may be linked to another aberrant modification of PDI, S-glutathionylation. Understanding the role of aberrant S-nitrosylation/S-glutathionylation of PDI in the pathogenesis of neurodegenerative diseases may provide insights into novel therapeutic interventions in the future.

  3. Identification of Candida albicans wall mannoproteins covalently linked by disulphide and/or alkali-sensitive bridges. (United States)

    Caminero, Antonio; Calvo, Enrique; Valentín, Eulogio; Ruiz-Herrera, José; López, Juan A; Sentandreu, Rafael


    This paper describes the results obtained by analysing the human pathogen Candida albicans cell wall subproteome by mass spectrometry, using extraction procedures aimed at releasing proteins bound by disulphide bridges (RAE-CWP) or alkali-labile ester linkages (ALS-CWP). Ten of the total proteins released from the wall by β-ME and/or NaOH contained a potential signal peptide, lacked a GPI cell wall hydrophobic C-terminal domain and were identified as true wall proteins by in silico analysis, whereas four additional proteins were identified as bound to the plasma membrane. The results surprisingly demonstrated that, in addition to the expected RAE-CWP and ALS-CWP proteins, 16 GPI proteins were bound to the wall by disulphide or alkali-sensitive bonds, since they were released by β-ME and/or NaOH. The biological significance of these results is discussed in relation to the added complexity of the organization of the proteins in the C. albicans cell wall. Copyright © 2014 John Wiley & Sons, Ltd.

  4. Three-dimensional printing of continuous-fiber composites by in-nozzle impregnation (United States)

    Matsuzaki, Ryosuke; Ueda, Masahito; Namiki, Masaki; Jeong, Tae-Kun; Asahara, Hirosuke; Horiguchi, Keisuke; Nakamura, Taishi; Todoroki, Akira; Hirano, Yoshiyasu


    We have developed a method for the three-dimensional (3D) printing of continuous fiber-reinforced thermoplastics based on fused-deposition modeling. The technique enables direct 3D fabrication without the use of molds and may become the standard next-generation composite fabrication methodology. A thermoplastic filament and continuous fibers were separately supplied to the 3D printer and the fibers were impregnated with the filament within the heated nozzle of the printer immediately before printing. Polylactic acid was used as the matrix while carbon fibers, or twisted yarns of natural jute fibers, were used as the reinforcements. The thermoplastics reinforced with unidirectional jute fibers were examples of plant-sourced composites; those reinforced with unidirectional carbon fiber showed mechanical properties superior to those of both the jute-reinforced and unreinforced thermoplastics. Continuous fiber reinforcement improved the tensile strength of the printed composites relative to the values shown by conventional 3D-printed polymer-based composites.

  5. Starch-modified magnetite nanoparticles for impregnation into cartilage (United States)

    Soshnikova, Yulia M.; Roman, Svetlana G.; Chebotareva, Natalia A.; Baum, Olga I.; Obrezkova, Mariya V.; Gillis, Richard B.; Harding, Stephen E.; Sobol, Emil N.; Lunin, Valeriy V.


    The paper presents preparation and characterization of starch-modified Fe3O4 nanoparticles (NPs) in aqueous dispersion after impregnation into healthy and damaged types of cartilage. We show that starch-modified dispersion has a narrower size distribution than a non-stabilized one. The average hydrodynamic radius of magnetite NPs in a dispersion used for impregnation into cartilage is (48 ± 1) nm with the width of the distribution from 5 to 200 nm. We investigate stability of aqueous magnetite NPs dispersions during storage and with increase in temperature (up to 70 °C). We find that polydisperse magnetite NPs can penetrate into cartilage and the size and concentration of impregnated particles depend on the organization of the tissue structure. The results confirm the possibility of application of magnetite NPs in diagnostics and laser treatment of degenerative cartilage deceases.

  6. Supercritical CO2 impregnation of polyethylene components for medical purposes

    Directory of Open Access Journals (Sweden)

    Gamse Thomas


    Full Text Available Modem hip and knee endoprosthesis are produced in titanium and to reduce the friction at the contact area polymer parts, mainly ultra-high molecular weight polyethylene (UHMW-PE, are installed. The polyethylene is impregnated with a-tocopherol (vitamin E before processing for remarkable decrease of oxidative degradation. Cross linked UHMW-PE offers much higher stability, but a-tocopherol cannot be added before processing, because a-tocopherol hinders the cross linking process accompanied by a heavy degradation of the vitamin. The impregnation of UHMW-PE with a-tocopherol has to be performed after the cross linking process and an accurate concentration has to be achieved over the cross section of the whole material. In the first tests UHMW-PE-cubes were stored in pure a-tocopherol under inert atmosphere at temperatures from 100 to 150 °C resulting in a high mass fraction of a-tocopherol in the edge zones and no constant concentration over the cross section. For better distribution and for regulating the mass fraction of a-tocopherol in the cross linked UHMW-PE material supercritical CO2 impregnation tests were investigated. Again UHMW-PE-cubes were impregnated in an autoclave with a-tocopherol dissolved in supercritical CO2 at different pressures and temperatures with variable impregnation times and vitamin E concentrations. Based on the excellent results of supercritical CO2 impregnation standard hip and knee cups were stabilized nearly homogeneously with varying mass fraction of a-tocopherol.

  7. UV-light exposure of insulin: pharmaceutical implications upon covalent insulin dityrosine dimerization and disulphide bond photolysis.

    Directory of Open Access Journals (Sweden)

    Manuel Correia

    Full Text Available In this work we report the effects of continuous UV-light (276 nm, ~2.20 W.m(-2 excitation of human insulin on its absorption and fluorescence properties, structure and functionality. Continuous UV-excitation of the peptide hormone in solution leads to the progressive formation of tyrosine photo-product dityrosine, formed upon tyrosine radical cross-linkage. Absorbance, fluorescence emission and excitation data confirm dityrosine formation, leading to covalent insulin dimerization. Furthermore, UV-excitation of insulin induces disulphide bridge breakage. Near- and far-UV-CD spectroscopy shows that UV-excitation of insulin induces secondary and tertiary structure losses. In native insulin, the A and B chains are held together by two disulphide bridges. Disruption of either of these bonds is likely to affect insulin's structure. The UV-light induced structural changes impair its antibody binding capability and in vitro hormonal function. After 1.5 and 3.5 h of 276 nm excitation there is a 33.7% and 62.1% decrease in concentration of insulin recognized by guinea pig anti-insulin antibodies, respectively. Glucose uptake by human skeletal muscle cells decreases 61.7% when the cells are incubated with pre UV-illuminated insulin during 1.5 h. The observations presented in this work highlight the importance of protecting insulin and other drugs from UV-light exposure, which is of outmost relevance to the pharmaceutical industry. Several drug formulations containing insulin in hexameric, dimeric and monomeric forms can be exposed to natural and artificial UV-light during their production, packaging, storage or administration phases. We can estimate that direct long-term exposure of insulin to sunlight and common light sources for indoors lighting and UV-sterilization in industries can be sufficient to induce irreversible changes to human insulin structure. Routine fluorescence and absorption measurements in laboratory experiments may also induce changes

  8. Simple fabrication of Ag nanoparticle-impregnated electrospun ...

    Indian Academy of Sciences (India)

    A facile method for the fabrication of electrospun polyurethane (PU) nanofibres impregnated with Ag nanoparticles (NPs) as an efficient and free-standing ... of Technology, Sydney, Broadway NSW 2007, Australia; Division of Mechanical Design Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756, Korea ...

  9. Studies of properties of rubber wood with impregnation of polymer

    Indian Academy of Sciences (India)


    Studies of properties of rubber wood with impregnation of polymer. RASHMI R DEVI and T K MAJI*. Department of ... solvents used in this study were of analytical grade. 2.2 Methods. 2.2a Sample preparation: The ... successive experiments were performed at that level of vacuum. 4.2 Variation of catalyst concentration and ...

  10. Properties of carbonisation products obtained from impregnated coal

    Czech Academy of Sciences Publication Activity Database

    Plevová, Eva; Šugárková, Věra; Kaloč, M.; Vaculíková, Lenka

    -, - (2008), s. 52-61. ISBN 978-80-248-1939-6 Grant - others:GA CŘ(CZ) GA105/00/1698 Institutional research plan: CEZ:AV0Z30860518 Keywords : chlorides * impregnation * coal Subject RIV: CC - Organic Chemistry

  11. Effects of impregnation with boron compounds on the surface ...

    African Journals Online (AJOL)


    The aim of this study was to determine the effects of impregnation with boron compounds on the surface adhesion strength of varnishes used woods. For this purpose, the test specimens prepared from Oriental beech (Fagus orientalis Lipsky) and European oak (Quercus petreae (Matt.) Liebl.) which met the requirements of ...

  12. Leaching of Silver from Silver-Impregnated Food Storage Containers (United States)

    Hauri, James F.; Niece, Brian K.


    The use of silver in commercial products has proliferated in recent years owing to its antibacterial properties. Food containers impregnated with micro-sized silver promise long food life, but there is some concern because silver can leach out of the plastic and into the stored food. This laboratory experiment gives students the opportunity to…

  13. Impregnation of LSM Based Cathodes for Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Højberg, Jonathan; Søgaard, Martin


    Composites cathodes consisting of strontium doped lanthanum manganite (LSM) and yttria stabilized zirconia have been impregnated with the nitrates corresponding to the nominal compositions: La0.75Sr0.25Mn1.05O3 +/-delta (LSM25), Ce0.8Sm0.2O2 (SDC) and a combination of both (dual). The latter...

  14. X-ray initiated polymerization of wood impregnants (United States)

    Cleland, Marshall R.; Galloway, Richard A.; Berejka, Anthony J.; Montoney, Daniel; Driscoll, Mark; Smith, Leonard; Scott Larsen, L.


    X-rays, derived from a high energy, high-current electron beam (EB), initiated in-situ polymerization of a unique class of monomers that were found to penetrate the cell walls of wood. X-rays initiated an auto-catalytic acrylic polymerization and penetrated through thick pieces of wood. The final cured product having the polymerizate, a polymer, both in the wood cell lumens and in the cell walls is called wood impregnated with a wood-polymer penetrant (WPP). The controlled lower dose rate of X-rays overcame disproportionation encountered when using higher dose-rate electron beam initiation. With X-rays, the in-situ polymerization took place in one exposure of modest dose. With EB, multiple passes were needed to avoid excessive heat build-up and monomer volatilization. Having entered the cell walls of the wood and then being polymerized within the cell walls, these radiation-cured unique monomers imparted outstanding dimensional stability upon exposure of the impregnated wood to humidity cycling. The preferred monomer system was also chemically modified prior to impregnation with agents that would remain in the wood and prevent the growth of fungi and other microbials. This technique differs from historic uses of monomers that merely filled the lumens of the wood (historic wood-polymer composites), which are only suitable for indoor use. The WPP impregnated wood that was either X-ray cured or EB cured demonstrated enhanced structural properties, dimensional stability, and decay resistance.

  15. Fire Resistance of Wood Impregnated with Soluble Alkaline Silicates


    Andrea Marisa Pereyra; Carlos Alberto Giudice


    The aim of this paper is to determine the fire performance of wood panels (Araucaria angustifolia) impregnated with soluble alkaline silicates. Commercial silicates based on sodium and potassium with 2.5/1.0 and 3.0/1.0 silica/alkali molar ratios were selected; solutions and glasses ...

  16. Textile impregnation with thermoplastic resin - models and application

    NARCIS (Netherlands)

    Loendersloot, Richard; Grouve, Wouter Johannes Bernardus; Lamers, E.A.D.; Wijskamp, Sebastiaan; Kelly, P.A.; Bickerton, S.; Lescher, P.; Govignon, Q.


    One of the key issues of the development of cost-effective thermoplastic composites for the aerospace industry is the process quality control. A complete, void free impregnation of the textile reinforcement by the thermoplastic resin is an important measure of the quality of composites. The

  17. Solvent impregnated resins for the recovery of gold from gold(I)thiourea solutions


    Fitzpatrick, Fiona


    Solvent Impregnated Resins (SIRs) are high surface area, macroporous, polymeric resins which have been physically impregnated with an organic solvent. In this research, three resins have been impregnated with Di-2- ethylhexyl phosphoric acid, a solvent which has shown selectivity to gold. The ability of the resins to recover gold(I)thiourea perchlorate from solution has been investigated. The resins have been studied both bare and when impregnated with the solvent and their efficiency was...

  18. Impairment of dynamic thiol-disulphide homeostasis in patients with idiopathic Parkinson's disease and its relationship with clinical stage of disease. (United States)

    Vural, Gonul; Gumusyayla, Sadiye; Bektas, Hesna; Deniz, Orhan; Alisik, Murat; Erel, Ozcan


    The aim of this study was to investigate dynamic thiol-disulphide homeostasis in patients with idiopathic Parkinson's disease and to determine its relationship with the clinical stage as assessed by the modified Hoehn and Yahr scale. Fifty-two patients with Parkinson's disease (PD), diagnosed according to the United Kingdom Brain Bank Criteria for idiopathic PD, and 41 healthy individuals were included in the study. Clinical staging of patients was performed according to the Hoehn and Yahr scale. Peripheral blood samples were taken from all participants, and their native thiol and total thiol concentrations were measured using the newly developed automated method. In addition, their amount of disulphide bonds, disulphide/native thiol, disulphide/total thiol and native thiol/total thiol ratios were calculated. Considering the data obtained from Parkinson's patients and the control group, both native thiol (-SH) and total thiol (-SH+-S-S) levels were found significantly lower in patients with Parkinson's disease. A negative and statistically significant relationship was found between both disease duration and disease stage and native thiol (-SH), total thiol (-SH+-S-S) levels and -SH/(-SH+-S-S-) ratio. A positive and statistically significant relationship was found between both disease duration and stage and -S-S-/-SH and -S-S-/(-SH+-S-S-) ratios. In patients with Parkinson's disease, dynamic thiol-disulphide homeostasis is disrupted, according to disease stage and duration. This balance, easily measured by using the newly developed automated method, can be used in monitoring disease progression. To our knowledge, our study will be the first report in the literature. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Exposure to creosote in the impregnation and handling of impregnated wood. (United States)

    Heikkilä, P R; Hämeilä, M; Pyy, L; Raunu, P


    The major components of vapors and polycyclic aromatic hydrocarbons in particulate matter were identified and quantified in two creosote impregnation plants and in the handling of treated wood. The vapors were collected on XAD-2 resin (recovery in the range of 82-102%) and analyzed by gas chromatography. Particulate polycyclic aromatic hydrocarbons were collected on glass fiber filters and analyzed with high-pressure liquid chromatography with a fluorescence detector. The main components of the vapors were naphthalene, methyl naphthalenes, indene, phenol, and its methyl homologues, benzothiophene, diphenyl, acenaphthene and fluorene. The exposure of the workers to vapors varied between 0.1 and 11 mg/m3. The concentrations of particulate polycyclic aromatic hydrocarbons varied between 0.2 and 46 micrograms/m3. The benzo(a)pyrene concentration was under 0.03 micrograms/m3, except in manual metal-arc welding and in the boring of railroad ties, where it was 0.24-0.89 micrograms/m3. In the measurement of creosote vapors, naphthalene could be used as an indicator agent.

  20. Activated carbon fibers and engineered forms from renewable resources (United States)

    Baker, Frederick S


    A method of producing activated carbon fibers (ACFs) includes the steps of providing a natural carbonaceous precursor fiber material, blending the carbonaceous precursor material with a chemical activation agent to form chemical agent-impregnated precursor fibers, spinning the chemical agent-impregnated precursor material into fibers, and thermally treating the chemical agent-impregnated precursor fibers. The carbonaceous precursor material is both carbonized and activated to form ACFs in a single step. The method produces ACFs exclusive of a step to isolate an intermediate carbon fiber.

  1. Activated carbon fibers and engineered forms from renewable resources (United States)

    Baker, Frederick S.


    A method of producing activated carbon fibers (ACFs) includes the steps of providing a natural carbonaceous precursor fiber material, blending the carbonaceous precursor material with a chemical activation agent to form chemical agent-impregnated precursor fibers, spinning the chemical agent-impregnated precursor material into fibers, and thermally treating the chemical agent-impregnated precursor fibers. The carbonaceous precursor material is both carbonized and activated to form ACFs in a single step. The method produces ACFs exclusive of a step to isolate an intermediate carbon fiber.

  2. The edible cocktail: the effect of sugar and alcohol impregnation on the crunchiness of fruit

    NARCIS (Netherlands)

    Scholten, E.; Peters, M.M.J.P.


    Vacuum impregnation is seen as a valuable technique for flavor pairing in the catering industry. One of the applications of this technique is the creation of edible cocktails by impregnating of fruits with liquors, leading to an interplay of different flavors. However, the effect of the impregnation

  3. The electrochemical modification of clenbuterol for biosensors of dopamine, norepinephrine, adrenalin, ascorbic acid and uric acid at paraffin-impregnated graphite electrode. (United States)

    Jin, Guan-Ping; Peng, Xia; Ding, Yan-Feng


    The electrochemical modification of clenbuterol (CLB) was studied at paraffin-impregnated graphite electrode (WGE) in two potential ranges of 0.0-1.6V and -1.2 to 1.2V. Various methods including X-ray photoelectron spectroscopy (XPS), UV-spectroelectrochemistry, infrared (IR) spectra and electrochemical techniques have been used to characterizing the modification. Clenbuterol can be modified at the electrode surface by carbon-nitrogen linkage or carbon-carbon linkage in 0.0-1.6V or -1.2 to 1.2V, respectively. The electrochemical behaviors of dopamine (DA), norepinephrine (NE), adrenalin (EP), ascorbic acid (AA) and uric acid (UA) were studied at clenbuterol-modified paraffin-impregnated graphite electrode (CLB/WGE), and it was found that all these compounds could be detected successfully.

  4. Modification of oil palm wood using acetylation and impregnation process (United States)

    Subagiyo, Lambang; Rosamah, Enih; Hesim


    The purpose of this study is chemical modification by process of acetylation and impregnation of oil palm wood to improve the dimensional stability. Acetylation process aimed at substituting the hydroxyl groups in a timber with an acetyl group. By increasing the acetyl groups in wood is expected to reduce the ability of wood to absorb water vapor which lead to the dimensions of the wood becomes more stable. Studies conducted on oil palm wood (Elaeis guineensis Jacq) by acetylation and impregnation method. The results showed that acetylated and impregnated wood oil palm (E. guineensis Jacq) were changed in their physical properties. Impregnation with coal ashfly provide the greatest response to changes in weight (in wet conditions) and after conditioning (dry) with the average percentage of weight gain of 198.16% and 66.41% respectively. Changes in volume indicates an increase of volume in the wet condition (imbibition) with the coal ashfly treatment gave highest value of 23.04 %, whereas after conditioning (dry) the highest value obtained in the treatment of gum rosin:ethanol with a volume increase of 13:44%. The highest changes of the density with the coal ashfly impregnation in wet condition (imbibition) in value of 142.32% and after conditioning (dry) of 57.87%. The result of reduction in water absorption (RWA) test showed that in the palm oil wood samples most stable by using of gum rosin : ethanol of 0.97%, whereas the increase in oil palm wood dimensional stability (ASE) is the best of 59.42% after acetylation with Acetic Anhydride: Xylene.

  5. Increasing operational life of brush-contact device in the turbine generator due to using lubricating molybdenum disulphide brushes (United States)

    Izotov, A. I.; Fominykh, A. A.; Nikulin, S. V.; Prokoshev, D. K.; Legoti, A. B.; Timina, N. V.


    A way of reducing irregular current distribution in multi-brush systems of sliding current transfer with its wear reduction due to installing lubricating molybdenum disulphide brushes on slip rings to ensure a greasing nano-sized cover on the slip ring surface is proposed. The authors give the results of industrial tests estimated on the performance effectiveness of lubricating brushes on slip rings of the TBB-320-2UZ-type turbine generator. The results showed that the lubricating brushes reduce a) the wear of 6110 OM+M and EG2AF+M brushes by 1.2 and 2.1 times respectively, b) current distribution irregularity in parallel operating brushes due to stabilizing the contact arc, and c) the temperature of the electrical brush-contact device due to the friction reduction in brushes.

  6. ER Stress and Unfolded Protein Response in Amyotrophic Lateral Sclerosis – A Controversial Role of Protein Disulphide Isomerase

    Directory of Open Access Journals (Sweden)

    Merja eJaronen


    Full Text Available Accumulation of proteins in aberrant conformation occurs in many neurodegenerative diseases. Furthermore, dysfunctions in protein handling in endoplasmic reticulum (ER and the following ER stress have been implicated in a vast number of diseases, such as amyotrophic lateral sclerosis (ALS. During excessive ER stress unfolded protein response (UPR is activated to return ER to its normal physiological balance. The exact mechanisms of protein misfolding, accumulation and the following ER stress could lead to neurodegeneration and the question whether UPR is a beneficial compensatory mechanism slowing down the neurodegenerative processes are of interest. Protein disulphide isomerase (PDI is a disulfide bond-modulating ER chaperone, which can also facilitate the ER-associated degradation (ERAD of misfolded proteins. In this review we discuss the recent findings of ER stress, UPR and especially the role of PDI in ALS.

  7. Use of insecticide-impregnated mosquito nets and other impregnated materials for malaria control in the Americas

    Directory of Open Access Journals (Sweden)

    R. H. Zimmerman


    Full Text Available This article reviews the current status of the use of insecticide-impregnated mosquito nets and other impregnated materials in the Americas. Studies from Brazil, Colombia, Ecuador, Guatemala, Peru, Suriname, and Venezuela are examined. It is concluded that most studies have suffered from experimental design errors, short duration problems, and/or inadequate measurement of health indicators. The review brings out the great difficulty of conducting scientific studies that attempt to measure the impact of insecticide-treated materials on malaria incidence. In particular, the low incidence of malaria in the Americas, the high prevalences of P. vivax and relapsing cases, and the relationship between human activity patterns and the crepuscular biting patterns of certain malaria vectors stand in the way of easy experimental design and execution. The utilization of impregnated mosquito nets or other impregnated materials as a major component of an integrated malaria control program would be premature at this time. However, it is recommended that well-conceived large-scale trials and interventions be considered when they are based on a thorough understanding of the dynamics of malaria transmission in the area of study.

  8. Use of insecticide-impregnated mosquito nets and other impregnated materials for malaria control in the Americas. (United States)

    Zimmerman, R H; Voorham, J


    This article reviews the current status of the use of insecticide-impregnated mosquito nets and other impregnated materials in the Americas. Studies from Brazil, Colombia, Ecuador, Guatemala, Peru, Suriname, and Venezuela are examined. It is concluded that most studies have suffered from experimental design errors, short duration problems, and/or inadequate measurement of health indicators. The review brings out the great difficulty of conducting scientific studies that attempt to measure the impact of insecticide-treated materials on malaria incidence. In particular, the low incidence of malaria in the Americas, the high prevalences of P. vivax and relapsing cases, and the relationship between human activity patterns and the crepuscular biting patterns of certain malaria vectors stand in the way of easy experimental design and execution. The utilization of impregnated mosquito nets or other impregnated materials as a major component of an integrated malaria control program would be premature at this time. However, it is recommended that well-conceived large-scale trials and interventions be considered when they are based on a thorough understanding of the dynamics of malaria transmission in the area of study.

  9. {alpha}' Subunit of soybean {beta}-conglycinin forms complex with rice glutelin via a disulphide bond in transgenic rice seeds. (United States)

    Motoyama, Takayasu; Maruyama, Nobuyuki; Amari, Yoshiki; Kobayashi, Kanna; Washida, Haruhiko; Higasa, Takahiko; Takaiwa, Fumio; Utsumi, Shigeru


    The alpha' and beta subunits of soybean beta-conglycinin were expressed in rice seeds in order to improve the nutritional and physiological properties of rice as a food. The alpha' subunit accumulated in rice seeds at a higher level than the beta subunit, but no detectable difference in mRNA transcription level between subunits was observed. Sequential extraction results indicate that the alpha' subunit formed one or more disulphide bonds with glutelin. Electron microscopic analysis showed that the alpha' subunit and the beta subunit were transported to PB-II together with glutelin. In mature transgenic seeds, the beta subunit accumulated in low electron density regions in the periphery of PB-II, whereas the alpha' subunit accumulated together with glutelin in high-density regions of the periphery. The subcellular localization of mutated alpha' subunits lacking one cysteine residue in the N-terminal mature region (alpha'DeltaCys1) or five cysteine residues in the pro and N-terminal mature regions (alpha'DeltaCys5) were also examined. Low-density regions were formed in PB-II in mature seeds of transgenic rice expressing alpha'DeltaCys 5 and alpha'DeltaCys1. alpha'DeltaCys5 was localized only in the low-density regions, whereas alpha'DeltaCys1 was found in both low- and high-density regions. These results suggest that the alpha' subunit could make a complex via one or more disulphide bonds with glutelin and accumulate together in PB-II of transgenic rice seeds.

  10. Preparation and characterization of activated carbon produced from pomegranate seeds by ZnCl 2 activation (United States)

    Uçar, Suat; Erdem, Murat; Tay, Turgay; Karagöz, Selhan


    In this study, pomegranate seeds, a by-product of fruit juice industry, were used as precursor for the preparation of activated carbon by chemical activation with ZnCl 2. The influence of process variables such as the carbonization temperature and the impregnation ratio on textural and chemical-surface properties of the activated carbons was studied. When using the 2.0 impregnation ratio at the carbonization temperature of 600 °C, the specific surface area of the resultant carbon is as high as 978.8 m 2 g -1. The results showed that the surface area and total pore volume of the activated carbons at the lowest impregnation ratio and the carbonization temperature were achieved as high as 709.4 m 2 g -1 and 0.329 cm 3 g -1. The surface area was strongly influenced by the impregnation ratio of activation reagent and the subsequent carbonization temperature.

  11. Reduction of Bromate by Cobalt-Impregnated Biochar Fabricated via Pyrolysis of Lignin Using CO2 as a Reaction Medium. (United States)

    Cho, Dong-Wan; Kwon, Gihoon; Ok, Yong Sik; Kwon, Eilhann E; Song, Hocheol


    In this study, pyrolysis of lignin impregnated with cobalt (Co) was conducted to fabricate a Co-biochar (i.e., Co/lignin biochar) for use as a catalyst for bromate (BrO3-) reduction. Carbon dioxide (CO2) was employed as a reaction medium in the pyrolysis to induce desired effects associated with CO2; (1) the enhanced thermal cracking of volatile organic compounds (VOCs) evolved from the thermal degradation of biomass, and (2) the direct reaction between CO2 and VOCs, which resulted in the enhanced generation of syngas (i.e., H2 and CO). This study placed main emphases on three parts: (1) the role of impregnated Co in pyrolysis of lignin in the presence of CO2, (2) the characterization of Co/lignin biochar, and (3) evaluation of catalytic capability of Co-lignin biochar in BrO3- reduction. The findings from the pyrolysis experiments strongly evidenced that the desired CO2 effects were strengthened due to catalytic effect of impregnated Co in lignin. For example, the enhanced generation of syngas from pyrolysis of Coimpregnated lignin in CO2 was more significant than the case without Co impregnation. Moreover, pyrolysis of Coimpregnated lignin in CO2 led to production of biochar of which surface area (599 m2 g-1) is nearly 100 times greater than the biochar produced in N2 (6.6 m2 g-1). Co/lignin biochar produced in CO2 also showed a great performance in catalyzing BrO3- reduction as compared to the biochar produced in N2.

  12. Heatshield material selection for advanced ballistic reentry vehicles. [rayon fiber cloth impregnated with phenolic resin (United States)

    Legendre, P. J.; Holtz, T.; Sikra, J. C.


    The Performance of staple rayon fiber and AVTEX continuous rayon fiber was evaluated as precursor materials for heatshields. The materials studied were referenced to the IRC FM5055A heatshield materials flown during the past decade. Three different arc jet facilities were used to simulate portions of the reentry environment. The IRC FM5055A and the AVTEX FM5055G, both continuous rayon fiber woven materials having the phenolic impregnant filled with carbon particles were compared. The AVTEX continuous fiber, unfilled material FM5822A was also examined to a limited extent. Test results show that the AVTEX FM5055G material provided a close substitute for the IRC FM5055A material both in terms of thermal protection and roll torque performance.

  13. Adsorption of arsenic, phosphorus and chromium by bismuth impregnated biochar: Adsorption mechanism and depleted adsorbent utilization. (United States)

    Zhu, Ningyuan; Yan, Tingmei; Qiao, Jun; Cao, Honglei


    Bismuth impregnated biochar were synthesized to deal with wastewater pollution. Nitrogen adsorption-desorption isotherms, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to determine the characteristics of adsorbents and explore the main adsorption mechanism. Results showed that bismuth particle was carried successfully within the biochar matrix, making contributions to creating micropore and boost specific surface area. The loaded bismuth, served as the adsorption site, rather than the specific surface area played an important role in arsenic and phosphorus adsorption. Batch adsorption experiments demonstrated a fit Langmuir model for arsenic (As) and phosphorus (P) and a suitable Freundlich model for chromium (Cr). Thermodynamic parameters depicted the endothermic nature and the spontaneous process for phosphate and arsenic adsorption. Besides, this contaminant-loaded carbon adsorbent was further applied for the removal of methylene blue from aqueous solution. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Calcite-impregnated defluidization structures in littoral sands of mono lake, california. (United States)

    Cloud, P; Lajoie, K R


    Associated locally with well-known tufa mounds and towers of Mono Lake, California, are subvertical, concretionary sand structures through which fresh calcium-containing artesian waters moved up to sites of calcium carbonate precipitation beneath and adjacent to the lake. The structures include closely spaced calcite-impregnated columns, tubes, and other configurations with subcylindrical to bizarre cross sections and predominantly vertical orientation in coarse, barely coherent pumice sands along the south shore of the lake. Many structures terminate upward in extensive calcareous layers of caliche and tufa. Locally they enter the bases of tufa mounds and towers. A common form superficially resembles root casts and animal burrows except that branching is mostly up instead of down. Similar defluidization structures in ancient sedimentary rocks have been mistakenly interpreted as fossil burrows.

  15. Biaxial flexural modulus of antibiotic-impregnated orthopedic bone cement. (United States)

    Leone, James; Johnson, Amy; Ziada, Samir; Hashemi, Ata; Adili, Anthony; de Beer, Justin


    Previously reported antibiotic-impregnated cement strengths have been based on uniaxial and fatigue testing methodologies. These methods may not provide an accurate characterization of bone cement's true load-bearing capacity in total joint replacement (TJR). The present study utilized biaxial testing to report on the properties of antibiotic-impregnated cement. Test groups included: PMMA mixed with Vancomycin, Gentamicin, Tobramycin, or no antibiotic (control). In comparison to the control group, PMMA samples mixed with powdered gentamicin resulted in an increase in the mean elastic modulus by 6.50% versus a drop noted with powdered vancomycin and tobramycin by 2.65 and 1.37% respectively. The mean elastic modulus in samples containing liquid gentamicin dropped by 11.6%. This study supports the continued use of powdered antibiotics when clinically indicated, but suggest caution in the use of liquid gentamicin in TJR.

  16. Performance characterization of PCM impregnated gypsum board for building applications


    Shukla, N; Fallahi, A.; Kosny, J.


    Previous research studies conducted on building components containing a phase-change material (PCM) have shown a great potential for direct and indirect energy and cost savings in the building envelopes. In particular, PCM impregnated gypsum boards, one of the most popular application of PCMs in buildings, have been reported to reduce building cooling loads by 7-20%. However, in order to best design and optimize the PCM-enhanced building materials, it is critical to accurately characterize th...

  17. Study on quality improvement of palm trunk by thermoplastic impregnation (United States)

    Rosli, F.; Ghazali, C. M. R.; Abdullah, M. M. A. B.; Hussin, K.


    Due to abundance of palm trunk waste, palm trunk can be used as alternative raw material of wood composites to replace future timber. However, the morphological of palm trunk is not truly woody material, so the quality improvement was studied by thermoplastic impregnation at different soaking time. The effect of thermoplastic resin impregnation on the morphological, physical and mechanical was investigated in this study. It was found that the amount of resin uptake to the palm trunk ranged from 3.85% to 6.25%. The density, thickness swelling and water absorption of treated palm trunk significantly improved. While, the modulus of rupture (MOR) and modulus of elasticity (MOE) of treated palm trunk was greater than untreated. This findings in this study indicated that thermoplastic resin would be considered alternative to formaldehyde-based resin to improved properties of palm trunk. At the request of all authors and with the approval of the proceedings editor, article 020268 titled, "Study on Quality Improvement of Palm Trunk by Thermoplastic Impregnation," is being retracted from the public record due to the fact that it is a duplication of article 020153 published in the same volume.

  18. Stannic chloride impregnated chitosan for defluoridation of water. (United States)

    Kahu, Shashikant; Shekhawat, Anita; Saravanan, D; Jugade, Ravin


    Chitosan, a potent amino polysaccharide, has been impregnated with Sn(IV) chloride for effective adsorption of fluoride from water. The Sn(IV) chloride impregnated chitosan was synthesized using microwave assisted technique. The material was thoroughly characterized using FTIR, SEM, EDX and XRD. The decrease in surface area and pore volume has been revealed from BET studies. Enhanced thermal stability of this material was ascertained by TGA-DTA studies. This Sn(IV) chloride impregnated chitosan(Sn-Ch) has been exploited for its defluoridation property. Various parameters like pH, amount of adsorbent, adsorption time etc have been optimized to achieve maximum defluoridation efficiency. Under optimum conditions, Sn-Ch was found to have adsorption capacity of 17. 63mg/g. The equilibrium studies showed that the data fits well with Freundlich isotherm model. Thermodynamics and kinetics parameters have been evaluated. The material has been applied for the defluoridation of real water sample. It was found to be recyclable material and can be regenerated and reused multiple times adding a greener dimension. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Synthesis, Characterisation, and Evaluation of a Cross-Linked Disulphide Amide-Anhydride-Containing Polymer Based on Cysteine for Colonic Drug Delivery

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    Vuanghao Lim


    Full Text Available The use of disulphide polymers, a low redox potential responsive delivery, is one strategy for targeting drugs to the colon so that they are specifically released there. The objective of this study was to synthesise a new cross-linked disulphide-containing polymer based on the amino acid cysteine as a colon drug delivery system and to evaluate the efficiency of the polymers for colon targeted drug delivery under the condition of a low redox potential. The disulphide cross-linked polymers were synthesised via air oxidation of 1,2-ethanedithiol and 3-mercapto-N-2-(3-mercaptopropionamide-3-mercapto propionic anhydride (trithiol monomers using different ratio combinations. Four types of polymers were synthesised: P10, P11, P151, and P15. All compounds synthesised were characterised by NMR, IR, LC-MS, CHNS analysis, Raman spectrometry, SEM-EDX, and elemental mapping. The synthesised polymers were evaluated in chemical reduction studies that were performed in zinc/acetic acid solution. The suitability of each polymer for use in colon-targeted drug delivery was investigated in vitro using simulated conditions. Chemical reduction studies showed that all polymers were reduced after 0.5–1.0 h, but different polymers had different thiol concentrations. The bacterial degradation studies showed that the polymers were biodegraded in the anaerobic colonic bacterial medium. Degradation was most pronounced for polymer P15. This result complements the general consensus that biodegradability depends on the swellability of polymers in an aqueous environment. Overall, these results suggest that the cross-linked disulphide-containing polymers described herein could be used as coatings for drugs delivered to the colon.

  20. A study of the mechanism of fluoride adsorption from aqueous solutions onto Fe-impregnated chitosan. (United States)

    Zhang, Jing; Chen, Nan; Tang, Zheng; Yu, Yang; Hu, Qili; Feng, Chuanping


    The adsorption of fluoride from aqueous solutions onto an Fe-impregnated chitosan (Fe-CTS) granular adsorbent was studied, and the adsorption capacity was determined to be 1.9736 mg g(-1) at an initial fluoride concentration of 10 mg L(-1). The effects of the initial fluoride concentration, dosage, and temperature were investigated using factorial design and analysis. The results indicated that high initial fluoride concentrations, low dosages, and low temperatures could enhance the fluoride adsorption capacity. In addition, Fe-CTS exhibited high selectivity for fluoride removal in the presence of high levels of several coexisting anions (nitrate, chloride, bicarbonate, and phosphate), except carbonate and sulfate. The adsorption process followed the Langmuir model at low fluoride concentrations and the Freundlich model at high initial fluoride concentrations. The data also fit the pseudo-second-order model. Scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, and extended X-ray absorption fine-structure (EXAFS) spectroscopy were used to elucidate the adsorption mechanism. The FTIR and EXAFS analyses revealed that Fe was chelated with -NH2 and -OH groups on the CTS, and fluoride adsorption on the Fe-CTS occurred due to ion exchange between chloride and fluoride. a granular Fe-impregnated chitosan (Fe-CTS) adsorbent was synthesized via chelation of Fe ions to -OH and -NH2 groups of CTS. The Fe-CTS granular adsorbent exhibited high performance for the adsorption of fluoride. The mechanism of fluoride adsorption on Fe-CTS was elucidated using EXAFS and FTIR analyses. Fluoride adsorption on Fe-CTS occurred via ion exchange between chloride and fluoride.

  1. Assignment of disulphide bridges in Par j 2.0101, a major allergen of Parietaria judaica pollen. (United States)

    Amoresano, Angela; Pucci, Piero; Duro, Giovanni; Colombo, Paolo; Costa, Maria A; Izzo, Vincenzo; Lamba, Doriano; Geraci, Domenico


    Par j 2.0101, a major allergen of the Parietaria judaica pollen, was expressed in E. coli, purified to homogeneity and fully characterised both at the structural and the functional level. The recombinant rPar j 2.0101 protein showed an allergenic activity in histamine release, skin prick tests and capacity to bind IgE, almost identical to that of the native allergens purified from aqueous pollen extract. The complete pattern of S-S bridges of rPar j 2.0101 was determined by enzymatic digestion with endoproteinase Lys-C followed by mass spectrometric analysis of the resulting peptide mixtures. The eight cysteines occurring in the allergenic protein were found to be paired into the following four disulphides: Cys35-Cys83, Cys45-Cys60, Cys61-Cys106 and Cys81-Cys121. This structural information probes Par j 2.0101 to attain a 3-D fold consistent with that of the non-specific lipid transfer protein (ns-LTP) family and it represents an effective molecular basis to develop modified antigens by selective site-directed mutagenesis for immunotherapy.

  2. Impact of high energy ball milling on the nanostructure of magnetite–graphite and magnetite–graphite–molybdenum disulphide blends

    Energy Technology Data Exchange (ETDEWEB)

    Österle, W., E-mail: [BAM Federal Institute for Materials Research and Testing, 12200 Berlin (Germany); Orts-Gil, G.; Gross, T.; Deutsch, C. [BAM Federal Institute for Materials Research and Testing, 12200 Berlin (Germany); Hinrichs, R. [Instituto de Geociências, UFRGS, P.O. Box 15001, 91501-970 Porto Alegre (Brazil); Vasconcellos, M.A.Z. [Instituto de Física, UFRGS, P.O. Box 15051, 91501-970 Porto Alegre (Brazil); Zoz, H.; Yigit, D.; Sun, X. [Zoz Group, 57482 Wenden (Germany)


    Different, partly complementary and partly redundant characterization methods were applied to study the transition of magnetite, graphite and MoS{sub 2} powders to mechanically alloyed nanostructures. The applied methods were: Transmission electron microscopy (TEM), Mössbauer spectroscopy (MS), Raman spectroscopy (RS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The main objective was to prepare a model material providing the essential features of a typical tribofilm forming during automotive braking, and to assess the impact of different constituents on sliding behaviour and friction level. Irrespective of the initial grain size, the raw materials were transferred to a nanocrystalline structure and mixed on a nanoscopic scale during high energy ball milling. Whereas magnetite remained almost unchanged, graphite and molybdenum disulphide were transformed to a nanocrystalline and highly disordered structure. The observed increase of the coefficient of friction was attributed to a loss of lubricity of the latter ingredient due to this transformation and subsequent oxidation. - Highlights: • Characterization of microstructural changes induced by high energy ball milling • Assessment of the potential of different characterization methods • Impact of mechanical alloying on tribological performance revealed by tests • Preparation of an artificial third body resembling the one formed during braking.

  3. Wear resistance and friction reduction in acrylo nitrile butadiene rubber through hybrid combination of graphite flakes and nano tungsten disulphide

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, Neha, E-mail: [Defence Material Store Research Development and Establishment (DMSRDE), DRDO, GT Road, Kanpur 208013, U.P (India); Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra (India); Pandey, Akanksha; Parihar, A. S.; Mishra, A. K.; Mukhopadhyay, K.; Prasad, N. E. [Defence Material Store Research Development and Establishment (DMSRDE), DRDO, GT Road, Kanpur 208013, U.P (India); Gandhi, M. N.; Bhattacharyya, A. R. [Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra (India)


    Friction and wear have considerable role in the life span of two interacting parts. Incorporation of nanofillers in polymers/elastomers matrix causes commendable changes in its tribologicalproperties. The main purpose of this work is to reduce the coefficient of friction and wear rate of Acrylo Nitrile Butadiene rubber (NBR). To achieve such objective traditionally well knownlubricants graphite(G), tungsten disulphide (WS{sub 2}) and there hybrid combination was incorporated in NBR matrix. Effect of applied load (force) and concentration of fillers on tribological properties of NBR had been studied. The filler incorporation enhanced the hardnessby 8%, showed resistance to hydraulic oil and aging effect also got improved significantly. A particular optimized concentration of NBR with hybrid combination of 2% WS{sub 2} and 4% Graphite showed minimum coefficient of friction as well as wear rate. A hypothesis could be attributed that similar lamellar structure of WS{sub 2} and Graphite along with formation of a stable nanoscale disulfide tribofilmcould result in lowering of friction. These substantially improved properties of nanoreinforced rubber materials would definitely pave promising path for plethora of potential technological applications.

  4. Fire Resistance of Wood Impregnated with Soluble Alkaline Silicates

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Giudice


    Full Text Available The aim of this paper is to determine the fire performance of wood panels (Araucaria angustifolia impregnated with soluble alkaline silicates. Commercial silicates based on sodium and potassium with 2.5/1.0 and 3.0/1.0 silica/alkali molar ratios were selected; solutions and glasses were previously characterized. Experimental panels were tested in a limiting oxygen chamber and in a two-foot tunnel. Results displayed a high fire-retardant efficiency using some soluble silicates.

  5. Differences and commonalities impregnation of dry and wet sand

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    Full Text Available The article is devoted to research new methods of physic-chemical methods of preventing deflation to protect railways and highways from such phenomena as exogenous sand drifts. In particular, first studied the possibility of using binders in sand wet state. Results can significantly extend the scope of the method, and identified with particular impregnation maintaining stability requirements protective cover reduces both the concentration previously recommended binders, and their costs, thereby securing implementation in practice of shifting sands resource-saving technology.

  6. Porous solid backbone impregnation for electrochemical energy conversion systems

    KAUST Repository

    Boulfrad, Samir


    An apparatus and method for impregnating a porous solid backbone. The apparatus may include a platform for holding a porous solid backbone, an ink jet nozzle configured to dispense a liquid solution onto the porous solid backbone, a positioning mechanism configured to position the ink jet nozzle proximate to a plurality of locations of the porous solid backbone, and a control unit configured to control the positioning mechanism to position the ink jet nozzle proximate to the plurality of locations and cause the ink jet nozzle to dispense the liquid solution onto the porous solid backbone.

  7. The effect of type and mixture of resin on the properties of impregnated paper

    Directory of Open Access Journals (Sweden)

    hossein Kermanian


    Full Text Available This study was carried out in order to investigate the effects of different types of resins and also their mixtures on the impregnated paper properties. In this regard, pure urea resin (100%, mixture of melamine and urea resins with various combinations (60/40 and 70/30 and 50/50, mixture of nano-fiber cellulose ratios of 1, 2 and 3 percent with urea resin and pure PVA (100% were used to impregnate of newsprint basic paper of Mazandaran wood and paper industries. Immersion of samples in the impregnation step were done in two time of 5 and 10 seconds. Next, melamine resin was used for surface coating and then absorption of resin in the impregnation and coating process measured. Results showed that in the impregnation step with pure urea (100%, in the respect of absorption rate and surface properties of melamine paper, the best time of impregnation was obtained 10 seconds. In the combined treatment, adding up to 30% melamine to urea resin, as impregnation step resin, offers better properties in terms of stain resistance, cigarette resistance, resistance to cracking and resistance to hot water steam for impregnatedmade paper. By adding nanocellulose up to 1% in impregnation resin, better properties is obtained for melamine paper. Also, PVA as impregnation resin, can be offer similar quality to pure urea in the resulting melamine papers.

  8. Drop transport and positioning on lubricant-impregnated surfaces. (United States)

    Hui Guan, Jian; Ruiz-Gutiérrez, Élfego; Xu, Ben Bin; Wood, David; McHale, Glen; Ledesma-Aguilar, Rodrigo; George Wells, Gary


    We demonstrate the transport and positioning of water droplets on macro-patterned lubricant-impregnated surfaces. The macro-patterning produces menisci features in the impregnating liquid layer which interact with a droplet via a capillary mechanism similar to the Cheerios effect. These interactions control the droplet motion and positioning on an otherwise completely slippery surface. We present experimental results using a V-shape channel geometry as a model system. The interaction between deformations on the lubricant layer induced by the droplet and the underlying V-shape geometry leads to both local and global equilibrium positions for the droplet within the channel. We present a mathematical model to quantify the transition from local equilibrium states to the global equilibrium state and show that the latter can be described on the basis of a force balance along the apparent contact line of the droplet. We highlight possible applications where lubricated macro-patterned surfaces can be used to control the motion and localisation of droplets.

  9. Bone impregnated hip screw in femoral neck fracture Clinicoradiological results

    Directory of Open Access Journals (Sweden)

    P K Sundar Raj


    Full Text Available Background: Femoral neck fractures are treated either by internal fixation or arthroplasty. Usually, cannulated cancellous screws are used for osteosynthesis of fracture neck of femur. The bone impregnated hip screw (BIHS is an alternative implant, where osteosyntehsis is required in femoral neck fracture. Materials and Methods: The BIHS is a hollow screw with thread diameter 8.3 mm, shank diameter 6.5 mm and wall thickness 2.2 mm and holes in the shaft of the screw with diameter 2 mm, placed in a staggered fashion. Biomechanical and animal experimental studies were done. Clinical study was done in two phases: Phase 1 in a group of volunteers, only with BIHS was used in a pilot study and phase 2 comparative study was done in a group with AO cannulated screws and the other group treated with BIHS. Results: In the phase 1 study, out of 15 patients, only one patient had delayed union. In phase 2, there were 78 patients, 44 patients in BIHS showed early union, compared to the rest 34 cases of AO cannulated screws Out of 44 patients with BIHS, 41 patients had an excellent outcome, 2 had nonunions and one implant breakage was noted. Conclusions: Bone impregnated hip screw has shown to provide early solid union since it incorporates the biomechanical principles and also increases the osteogenic potential and hence, found superior to conventional cannulated cancellous screw.

  10. Investigating conformational stability of bovine pancreatic phospholipase A2: a novel concept in evaluating the contribution of the 'native-framework' of disulphides to the global conformational stability of proteins. (United States)

    Singh, R Rajesh; Chang, Jui-Yoa


    Bovine pancreatic PLA(2) (phospholipase A(2)) is a 14 kDa protein whose structure is highly cross-linked by seven disulphide bonds. We investigated the structural stability of this enzyme by the method of 'disulphide-scrambling' with denaturants such as urea, GdmCl (guanidine hydrochloride), GdmSCN (guanidine thiocyanate) and at high temperatures in the presence of 2-mercaptoethanol (0.2 mM) as thiol initiator. Reverse-phase HPLC was used to follow denaturation. To denature 50% of the native protein, 1.25 M GdmSCN, approx. 3 M GdmCl and higher than 8 M urea were required. Only 20% of the protein was denatured after 2 h at 60 degrees C, whereas complete denaturation was seen after 2 h at 70 degrees C and within 30 min at 80 degrees C. A distinct enhancement of stability was observed when denaturation was conducted in the presence of 10 mM calcium chloride, which has not been reported previously. CD studies of GdmCl denaturation of bovine PLA(2) showed that 2.5 M GdmCl was required to denature 50% of the protein in the presence of 0.2 mM 2-mercaptoethanol (in agreement with the HPLC analysis), whereas 6.4 M GdmCl was necessary to denature 50% of the protein in the absence of a thiol initiator. Conformational stability (Delta G (water)) was estimated to be 8.7 kcal/mol (1 cal=4.184 J) by 'disulphide-intact' denaturation (where 'native' disulphide framework was unaffected) and 2.5 kcal/mol by 'disulphide-scrambling' denaturation (involved breaking of native disulphides and formation of 'non-native' ones). The difference, Delta(Delta G (water)), of 6.2 kcal/mol was the conformational stability contributed by the 'native-framework' of seven disulphides. Using bovine PLA(2) as an example, we have demonstrated a novel comparative technique, where the conformational stability study of a disulphide-containing protein, with a common denaturant, in both the presence and absence of catalytic amounts of a thiol initiator can be used as a convenient method to estimate selectively

  11. D-penicillamine prevents ram sperm agglutination by reducing the disulphide bonds of a copper-binding sperm protein. (United States)

    Leahy, T; Rickard, J P; Aitken, R J; de Graaf, S P


    Head-to-head agglutination of ram spermatozoa is induced by dilution in the Tyrode's capacitation medium with albumin, lactate and pyruvate (TALP) and ameliorated by the addition of the thiol d-penicillamine (PEN). To better understand the association and disassociation of ram spermatozoa, we investigated the mechanism of action of PEN in perturbing sperm agglutination. PEN acts as a chelator of heavy metals, an antioxidant and a reducing agent. Chelation is not the main mechanism of action, as the broad-spectrum chelator ethylenediaminetetraacetic acid and the copper-specific chelator bathocuproinedisulfonic acid were inferior anti-agglutination agents compared with PEN. Oxidative stress is also an unlikely mechanism of sperm association, as PEN was significantly more effective in ameliorating agglutination than the antioxidants superoxide dismutase, ascorbic acid, α-tocopherol and catalase. Only the reducing agents cysteine and DL-dithiothreitol displayed similar levels of non-agglutinated spermatozoa at 0 h compared with PEN but were less effective after 3 h of incubation (37 °C). The addition of 10 µM Cu(2+) to 250 µM PEN + TALP caused a rapid reversion of the motile sperm population from a non-agglutinated state to an agglutinated state. Other heavy metals (cobalt, iron, manganese and zinc) did not provoke such a strong response. Together, these results indicate that PEN prevents sperm association by the reduction of disulphide bonds on a sperm membrane protein that binds copper. ADAM proteins are possible candidates, as targeted inhibition of the metalloproteinase domain significantly increased the percentage of motile, non-agglutinated spermatozoa (52.0% ± 7.8) compared with TALP alone (10.6% ± 6.1). © 2016 Society for Reproduction and Fertility.

  12. Phase Transformation in Monolayer Molybdenum Disulphide (MoS2) with and without Defects under Tension Predicted by Atomistic Simulations (United States)

    Dillon, Keith

    In addition to its use as a solid lubricant, molybdenum disulphide (MoS 2) has gained recent attention as a possible substitute for silicon as it is increasingly difficult to keep shrinking down electronic devices made of silicon, the conventional electronic material. When thinned down to atomic thickness, monolayer MoS2 possesses very unique and promising electronic and electrical properties. Unlike electronic and electrical properties, knowledge of the mechanical properties and role of structural defects on these properties of monolayer MoS2 is unexplored. For this thesis, the two main objectives are (1) to gain insight about the failure mechanism of monolayer MoS2 by modeling nanoindentation performed on suspended free standing membrane with comparison to experiment and (2) to explore the influence of structural defects on the mechanical properties of monolayer MoS2 by modelling monolayer MoS2 membranes with defects and simulating the same nanoindentation process as in part (1). It is shown that the force required for fracture of the MoS2 monolayer increases with increasing indenter diameter. This relationship and the magnitudes of the breaking forces computed in this work are consistent with experiments presented in the literature. A phase transformation, caused by an abrupt drop in the S-S intralayer Z dimension, is observed prior to failure during both defect-free and defect-containing membrane simulations. This phase transformation is also observed in uniaxial tension simulations. Analysis suggests that structural defects alter the failure mechanisms of monolayer MoS2 and thus reduce its mechanical performance. For point defects, the phase transformation initiates from accumulated vacancies away from the center of the membrane and accelerates the new phase propagation process. For grain boundary structures, it was found that their fracture strength is independent of the grain boundary energy.

  13. Modelling of the disulphide-swapped isomer of human insulin-like growth factor-1: implications for receptor binding. (United States)

    Gill, R; Verma, C; Wallach, B; Ursø, B; Pitts, J; Wollmer, A; De Meyts, P; Wood, S


    Insulin-like growth factor-1 (IGF-1) is a serum protein which unexpectedly folds to yield two stable tertiary structures with different disulphide connectivities; native IGF-1 [18-61,6-48,47-52] and IGF-1 swap [18-61,6-47, 48-52]. Here we demonstrate in detail the biological properties of recombinant human native IGF-1 and IGF-1 swap secreted from Saccharomyces cerevisiae. IGF-1 swap had a approximately 30 fold loss in affinity for the IGF-1 receptor overexpressed on BHK cells compared with native IGF-1. The parallel increase in dose required to induce negative cooperativity together with the parallel loss in mitogenicity in NIH 3T3 cells implies that disruption of the IGF-1 receptor binding interaction rather than restriction of a post-binding conformational change is responsible for the reduction in biological activity of IGF-1 swap. Interestingly, the affinity of IGF-1 swap for the insulin receptor was approximately 200 fold lower than that of native IGF-1 indicating that the binding surface complementary to the insulin receptor (or the ability to attain it) is disturbed to a greater extent than that to the IGF-1 receptor. A 1.0 ns high-temperature molecular dynamics study of the local energy landscape of IGF-1 swap resulted in uncoiling of the first A-region alpha-helix and a rearrangement in the relative orientation of the A- and B-regions. The model of IGF-1 swap is structurally homologous to the NMR structure of insulin swap and CD spectra consistent with the model are presented. However, in the model of IGF-1 swap the C-region has filled the space where the first A-region alpha-helix has uncoiled and this may be hindering interaction of Val44 with the second insulin receptor binding pocket.

  14. Diallyl disulphide and lovastatin: effects on energy and protein utilisation in, as well as methane emission from, sheep. (United States)

    Klevenhusena, Fenja; Duval, Stephane; Zeitz, Johanna O; Kreuzer, Michael; Soliva, Carla R


    Currently research on feed supplementation with natural compounds to improve energy and protein utilisation and to mitigate the greenhouse gas methane in ruminants is intensively pursued. Two compounds, diallyl disulphide (DADS), an important component of garlic oil, and lovastatin, an inhibitor of a key enzyme of methanogenic Archaea, were selected on the basis of their in vitro anti-methanogenic potential. In three 23-day experimental runs, six sheep received hay and concentrate in a duplicate 3 x 3 Latin square design. The concentrate was either not supplemented or supplemented with either 4 g DADS or 80 mg lovastatin per kg of total dietary dry matter. There were no refusals of concentrate for any treatment. Respiratory measurements were conducted on experimental days 7/8 (Period 1) and days 17/18 (Period 2). Relative to the control, digestibility of neutral detergent fibre (NDF) tended to increase (p = 0.09) with DADS by 14%. This was associated with an increased (p = 0.07) body energy retention of the animals. Effects on nitrogen balance and ruminal fermentation traits were never significant. No influence of supplements or period was found on total daily CH4 production which averaged at 28.6 g per sheep. However, across both periods the amount of CH4 produced per kg NDF digested was lower (-8%; p = 0.02) with DADS than without supplementation, and the lovastatin treatment ranged in between. In conclusion, the study demonstrated a certain potential of DADS to improve fibre digestion and body energy retention and to limit CH4 formation in relation to digestible fibre intake, while lovastatin remained ineffective.

  15. Impregnation of mesoporous silica for catalyst preparation studied with differential scanning calorimetry

    NARCIS (Netherlands)

    Eggenhuisen, T.M.|info:eu-repo/dai/nl/313959498; van Steenbergen, M.J.|info:eu-repo/dai/nl/304839302; Talsma, H.|info:eu-repo/dai/nl/08138212X; de Jongh, P.E.|info:eu-repo/dai/nl/186125372; de Jong, K.P.|info:eu-repo/dai/nl/06885580X


    Aqueous impregnation of mesoporous silica as a first step in catalyst preparation was studied to investigate the distribution of the metal-precursor solution over the support. The degree of pore-filling after impregnation was determined using the freezing point depression of confined liquids. A

  16. Biomonitoring in wearers of permethrin impregnated battle dress uniforms in Afghanistan and Germany. (United States)

    Kegel, Peter; Letzel, Stephan; Rossbach, Bernd


    To analyse differences in uptake of the insecticide permethrin in wearers of non-impregnated and permethrin impregnated battle dress uniforms (BDU) in Afghanistan and Germany. In two separate studies, in April 2003-January 2004 (study I, n=549) and in February-April 2005 (study II, n=195), healthy female and male members of the German Federal Armed Forces were equipped with permethrin impregnated BDU (two sub-cohorts in Germany and one in Afghanistan) while members equipped with non-impregnated uniforms served as a control group. Human biomonitoring was conducted before, during and after wearing the uniforms by measuring permethrin metabolites in urine samples via GC-MS. Subjects of the Afghan and German control groups had permethrin levels in the range of the German general population. In contrast, subjects wearing impregnated BDU had about 200-fold higher exposure levels. Within this group, subjects located in Afghanistan and smokers had significantly higher exposure levels. Internal exposure decreased with increasing duration of use of impregnated BDU. There is no evidence for a higher background permethrin contamination in military bases located in Afghanistan compared to Germany. Daily use of permethrin impregnated BDU is associated with significantly higher permethrin uptake compared to the general population. Hand-mouth contact by smoking can increase uptake which also seems to be influenced by the duration of use of impregnated BDU.

  17. Kl-impregnated Oyster Shells as a Solid Catalyst for Soybean Oil Transesterificaton (United States)

    Research on inexpensive and green catalysts is needed for economical production of biodiesel. The goal of the research was to test KI-impregnated oyster shell as a solid catalyst for transesterification of soybean oil. Specific objectives were to characterize KI-impregnated oyster shell, determine t...

  18. 21 CFR 529.1003 - Flurogestone acetate-impregnated vaginal sponge. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Flurogestone acetate-impregnated vaginal sponge. 529.1003 Section 529.1003 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS CERTAIN OTHER DOSAGE FORM NEW ANIMAL DRUGS § 529.1003 Flurogestone acetate-impregnate...

  19. Modification of fast-growing Chinese Fir wood with unsaturated polyester resin: Impregnation technology and efficiency (United States)

    Ma, Qing; Zhao, Zijian; Yi, Songlin; Wang, Tianlong

    In this study, Chinese Fir was impregnated with unsaturated polyester resin to enhance its properties. Samples 20 mm × 20 mm × 20 mm in size were split into different sections with epoxy resin and tinfoil and subjected to an impregnation experiment under various parameters. Vacuum degree was -0.04 MPa, -0.06 MPa or -0.08 MPa and vacuum duration was 15 min, 30 min, or 45 min. The results indicated that impregnation weight percent gain is linearly dependent on curing weight percent gain. Vacuum duration appears to have less influence on the curing weight percent gain than vacuum degree, and impregnation was most successful at the transverse section compared to other sections. The optimal impregnation parameters were 30 min modification under -0.08 MPa vacuum followed by 120 min at atmospheric pressure for samples 200 mm × 100 mm × 20 mm in size. Uneven distribution of weight percent gain and cracking during the curing process suggested that 30 min post-processing at -0.09 MPa vacuum was the most effective way to complete the impregnation process. The sample's bending strength and modulus of elasticity increased after impregnation treatment. Bending strength after impregnation without post-processing reached 112.85%, but reached 71.65% with vacuum-processing; modulus of elasticity improved 67.13% and 58.28% without and with post-processing, respectively.

  20. Impregnation of bio-oil from small diameter pine into wood for moisture resistance (United States)

    Thomas J. Robinson; Brian K. Via; Oladiran Fasina; Sushil Adhikari; Emily Carter


    Wood pyrolysis oil consists of hundreds of complex compounds, many of which are phenolic-based and exhibit hydrophobic properties. Southern yellow pine was impregnated with a pyrolysis oil-based penetrant using both a high pressure and vacuum impregnation systems, with no significant differences in retention levels. Penetrant concentrations ranging from 5-50% pyrolysis...

  1. The sampling of sulfur dioxide in air with impregnated filter paper

    NARCIS (Netherlands)

    Huygen, C.


    A method is suggested for the sampling of sulfur dioxide in air with impregnated filter paper instead of bubblers. The best aqueous impregnating solution contained potassium hydroxide with glycerol or triethanolamine. The possibilities and limitations of the method are discussed. High collection

  2. Effect of disulphide bond position on salt resistance and LPS-neutralizing activity of α-helical homo-dimeric model antimicrobial peptides. (United States)

    Nan, Yong Hai; Shin, Song Yub


    To investigate the effects of disulphide bond position on the salt resistance and lipopolysaccharide (LPS)-neutralizing activity of α-helical homo-dimeric antimicrobial peptides (AMPs), we synthesized an α-helical model peptide (K6L4W1) and its homo-dimeric peptides (di-K(6)L(4)W(1)-N, di-K(6)L(4)W(1)-M, and di-K(6)L(4)W(1)-C) with a disulphide bond at the N-terminus, the central position, and the C-terminus of the molecules, respectively. Unlike (6)L(4)W(1) and di-K(6)L(4)W(1)-M, the antimicrobial activity of di-K(6)L(4)W(1)-N and di-K(6)L(4)W(1)-C was unaffected by 150 mM NaCl. Both di-K(6)L(4)W(1)-N and di-K(6)L(4)W(1)-C caused much greater inhibitory effects on nitric oxide (NO) release in LPS-induced mouse macrophage RAW 264.7 cells, compared to di-K(6)L(4)W(1)-M. Taken together, our results indicate that the presence of a disulphide bond at the N- or C-terminus of the molecule, rather than at the central position, is more effective when designing salt-resistant α-helical homo-dimeric AMPs with potent antimicrobial and LPS-neutralizing activities. [BMB reports 2011; 44(11): 747-752].

  3. Carbon Materials Research (United States)


    wt% polyvinyl alcohol (Airvol 2005 PVA,Air Products andChemicals,Allentown, PA). The mixture was uniaxially pressed into bars (11 mm long × 9.9 mm...process. First, carbon fibers, which carry the mechanical load, are woven, braided, felted, or filament wound into a preform which has the shape of the... filaments , injection of brake preforms, and in fab- rication of anode materials for lithium ion batteries. The principle behind the impregnation with in

  4. Preparation of Highly Conductive Yarns by an Optimized Impregnation Process (United States)

    Amba Sankar, K. N.; Mohanta, Kallol


    We report the development of the electrical conductivity in textile yarns through impregnation and post-treatment of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The conductive polymer is deposited on fibers, which fills the gap space within the hierarchical structure of the yarns. Organic nonpolar solvents act as reducing agent to increase the density of PEDOT moieties on the yarns, galvanizing increment in conductivity values. Post-treatment by ethylene glycol transforms the resonance configuration of the conductive moieties of conjugated polymer, which helps in further enhancement of electrical conductivity of the yarns. We have optimized the method in terms of loading and conformal change of the polymer to have a lesser resistance of the coated conductive yarns. The minimum resistance achieved has a value of 77 Ωcm-1. This technique of developing conductivity in conventional yarns enables retaining the flexibility of yarns and feeling of softness which would find suitable␣applications for wearable electronics.

  5. Impregnation of silver nanoparticles into polysaccharide substrates and their properties. (United States)

    Hassabo, Ahmed G; Nada, Ahmed A; Ibrahim, Hassan M; Abou-Zeid, N Y


    A method to impregnate silver nanoparticles (AgNPs) into different polysaccharides substrates (cellulose powder (CP), microcrystalline cellulose (MCC), carboxymethyl cellulose (CMC) and chitosan (Chit)) by using glucose as reducing agent, is presented. X-ray diffraction analyses of polysaccharides coated with AgNPs showed the formation of silver particle sizes in the range of 3.7-5.6 nm and have almost spherical shape. The entire prepared composite shows antimicrobial effect. The antibacterial activity of polysaccharides loaded with silver nanoparticles was evaluated against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) bacteria. The results suggest excellent antibacterial activity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Fiber ceramic structures based on liquid impregnation technique (United States)

    Krenkel, W.; Schanz, P.

    For future reentry vehicles ceramic matrix composites (CMC) are very favorable materials for hot structures and thermal protection systems. This paper describes the fabrication and evaluation of CMC-components manufactured by the liquid impregnation technique. This process offers the potential for a low-cost CMC production for all components which can be fabricated by resin transfer molding (RTM) or other techniques for reinforcing polymers. The two main fabrication steps, the component shaping and the matrix conversion to ceramics, are described in detail. Experimental data on infiltration parameters as well as mechanical properties and oxidation resistance of the produced fiber ceramics were determined. Emphasis was given on manufacturing real components like panels with integrated stringers to demonstrate the feasibility of the process.

  7. Preparation of Highly Conductive Yarns by an Optimized Impregnation Process (United States)

    Amba Sankar, K. N.; Mohanta, Kallol


    We report the development of the electrical conductivity in textile yarns through impregnation and post-treatment of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The conductive polymer is deposited on fibers, which fills the gap space within the hierarchical structure of the yarns. Organic nonpolar solvents act as reducing agent to increase the density of PEDOT moieties on the yarns, galvanizing increment in conductivity values. Post-treatment by ethylene glycol transforms the resonance configuration of the conductive moieties of conjugated polymer, which helps in further enhancement of electrical conductivity of the yarns. We have optimized the method in terms of loading and conformal change of the polymer to have a lesser resistance of the coated conductive yarns. The minimum resistance achieved has a value of 77 Ωcm-1. This technique of developing conductivity in conventional yarns enables retaining the flexibility of yarns and feeling of softness which would find suitable applications for wearable electronics.

  8. Carbon-Supported Iron Oxide Particles

    DEFF Research Database (Denmark)

    Meaz, T.; Mørup, Steen; Koch, C. Bender


    A carbon black ws impregnated with 6 wt% iron using an aqueous solution of iron nitrate. The impregnated carbon was initially dried at 125 C. The effect of heating of the iron oxide phase was investigated at temperatures between 200 and 600 C using Mossbauer spectroscopy. All heat treatments were...... done in an oxygen-containing atmosphere. Ferrihydrite is formed and is stable at and below a temperature of 300 C. At 600 C small particles of maghemite is the dominant iron oxide. A transformation reaction is suggested....

  9. Development and Evaluation of Carbon-Carbon Threaded Fasteners for High Temperature Applications


    Juhi Kushwaha; V. Pawan Kumar; K.H. Sinnur


    Carbon-Carbon (C-C) threaded fasteners have been developed for joining C-C composites experiencing temperature above 1500 ˚C. The fasteners were fabricated from spun yarn graphitized carbon fabric through resin route and from needle punched carbon felt through pitch route techniques. The preforms were processed with multiple cycles of impregnation, carbonisation, and graphitisation up to densities of 1.78 gcm-3 and 1.90 gcm-3. Densification process cycles were repeated to obtain compos...

  10. the optimum value index in the yield of carbon through continuous

    African Journals Online (AJOL)

    Dr Obe

    carbon composites is achieved by the impregnation of fibre tows, weaves or skeletons (3-D structures of felts) with the thermosetting resins or by chemical vapour infiltration with gaseous hydrocarbons. All of these processes are slow, expensive and.

  11. Differential labelling of cysteines for simultaneous identification of thioredoxin h-reducible disulphides in native protein extracts: insight into recognition and regulation of proteins in barley seeds by thioredoxin h

    DEFF Research Database (Denmark)

    Maeda, Kenji; Finnie, Christine; Svensson, Birte


    , thioredoxin h-reducible disulphide bonds in individual target proteins are identified using a novel strategy based on differential alkylation of cysteine thiol groups by iodoacetamide and 4-vinylpyridine. This method enables the accessible cysteine side chains in the thiol form (carbamidomethylated......-amylase/subtilisin inhibitor (BASI) by barley thioredoxin h isoform 1 was analysed. Furthermore, the method was coupled with twodimensional electrophoresis for convenient thioredoxin h-reducible disulphide identification in barley seed extracts without the need for protein purification or production of recombinant proteins...

  12. The modification of activated carbon cloth by alumina deposition


    Hayes, Robert Andrew


    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. The impregnation of mesoporous carbon cloth with alumina has been studied. The most successful method of impregnation resulted from preparation of the alumina phase by a sol/gel route. This method involves a boehmite intermediate, and the heating environment for the thermal transition of boehmite to the final alumina was investigated. Heat treatment of the boehmite intermediate under flowing...

  13. Preparation and in vitro characterization of gentamycin-impregnated biodegradable beads suitable for treatment of osteomyelitis. (United States)

    Meyer, J D; Falk, R F; Kelly, R M; Shively, J E; Withrow, S J; Dernell, W S; Kroll, D J; Randolph, T W; Manning, M C


    A new method for preparing poly(L-lactide) (PLA) biodegradable beads impregnated with an ionic aminoglycoside, gentamycin, is described. The process employs hydrophobic ion pairing to solubilize gentamycin in a solvent compatible with PLA, followed by precipitation with a compressed antisolvent (supercritical carbon dioxide). The resulting precipitate is a homogeneous dispersion of the ion-paired drug in PLA microspheres. The microspheres are approximately 1 microm in diameter and can be compressed into beads (3-6 mm in diameter) strung on surgical sutures for implantation. The bead strings exhibit no significant change in release kinetics upon sterilization with a hydrogen peroxide plasma (Ster-Rad). The kinetics of gentamycin release from the PLA beads are consistent with a matrix-controlled diffusion mechanism. While nonbiodegradable poly(methyl methacrylate) (PMMA) beads initially release gentamycin in a similar manner, the drug release from PMMA ceases after 8 or 9 weeks, while the PLA beads continue to release drug for over 4 months. Moreover, only 10% of the gentamycin is released from the PMMA beads, while PLA beads release more than 60% of their load, if serum is present in the release medium. The PLA system displays improved release kinetics relative to PMMA, is biodegradable, is unaltered by gas sterilization, can be used for a range of antibiotics, and can be manipulated without disintegration. These are all desirable properties for an implantable drug delivery system for the prevention or treatment of osteomyelitis.

  14. Preparation of Palladium-Impregnated Ceria by Metal Complex Decomposition for Methane Steam Reforming Catalysis

    Directory of Open Access Journals (Sweden)

    Worawat Wattanathana


    Full Text Available Palladium-impregnated ceria materials were successfully prepared via an integrated procedure between a metal complex decomposition method and a microwave-assisted wetness impregnation. Firstly, ceria (CeO2 powders were synthesized by thermal decomposition of cerium(III complexes prepared by using cerium(III nitrate or cerium(III chloride as a metal source to form a metal complex precursor with triethanolamine or benzoxazine dimer as an organic ligand. Palladium(II nitrate was consequently introduced to the preformed ceria materials using wetness impregnation while applying microwave irradiation to assist dispersion of the dopant. The palladium-impregnated ceria materials were obtained by calcination under reduced atmosphere of 10% H2 in He stream at 700°C for 2 h. Characterization of the palladium-impregnated ceria materials reveals the influences of the metal complex precursors on the properties of the obtained materials. Interestingly, the palladium-impregnated ceria prepared from the cerium(III-benzoxazine dimer complex revealed significantly higher BET specific surface area and higher content of the more active Pdδ+ (δ > 2 species than the materials prepared from cerium(III-triethanolamine complexes. Consequently, it exhibited the most efficient catalytic activity in the methane steam reforming reaction. By optimization of the metal complex precursors, characteristics of the obtained palladium-impregnated ceria catalysts can be modified and hence influence the catalytic activity.

  15. Preparation and Properties of Moisture-absorbing Film Impregnated with Polyacrylic Acid Partial Sodium Salt Material

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youn Suk; Park, Insik [Yonsei University, Wonju (Korea, Republic of); Choi, Hong Yeol [CJ Cheiljedang, Seoul (Korea, Republic of)


    Moisture is a major factor causing the deteriorative physical change, microbial growth, and chemical reaction of the products. In this study, the moisture absorbing composite films have been prepared with moisture absorbing material of polyacrylic acid partial sodium salt (PAPSS) impregnated on LLDPE polymer for the functional packaging applications. The results showed that PAPSS impregnated film illustrated uniformly dispersed PAPSS particles in the LLDPE polymer matrix. The transparency of the PAPSS impregnated film decreased slightly at higher PAPSS concentrations. An increase in the PAPSS content for moisture-absorbing films showed a similar decrease in tensile strength, percent elongation at break, and tear strength. Their values of films impregnated with PAPSS of 0.5, 1, and 2% showed no significant difference. Meanwhile, 4% PAPSS films significantly decreased the values of mechanical properties compared to the films impregnated with different PAPSS levels. Values of the oxygen permeability and water vapor permeability for PAPSS impregnated films decreased significantly with greater PAPSS. The results indicate that 4% PAPSS impregnated in LLDPE films had high affinity of moisture absorbencies compared to the other films. The mathematical equation that best described the moisture sorption isotherm of each film sample was the GAB equation at 25 .deg. C. The crystallization and melting temperatures of PAPSS films were influenced by the addition of PAPSS material, but showed good thermal stability.

  16. Preparation and Characterisation of Activated Carbon From Pumpkin Seed Shell Using H3PO4


    DEMIRAL, Ilknur; AYDIN ŞAMDAN, Canan


    In this study, activated carbons were produced from pumpkin seed shell by chemical activation. In chemical activation, H3PO4 was used as chemical agent. The effects of impregnation ratio (IR) and activation temperature were investigated. Activation temperatures and impregnation ratios were selected in the range of 400–600 °C and 1–3, respectively. The surface area, pore volumes, pore size distribution and average pore diameter of the activated carbons were characterized by N2 adsorption at 77...

  17. In vivo assessment of antimicrobial efficacy of silver-impregnated contact lens storage cases. (United States)

    Dantam, Jaya; Zhu, Hua; Willcox, Mark; Ozkan, Jerome; Naduvilath, Thomas; Thomas, Varghese; Stapleton, Fiona


    To evaluate microbial contamination in silver-impregnated contact lens (CL) storage cases while establishing the effect of "wet " and "dry " case maintenance and to determine its association with clinical signs, symptoms, and compliance. Two noncontemporaneous prospective studies were conducted. Regular storage cases in study 1 (n = 40) and silver-impregnated cases in study 2 (n = 41) were used in conjunction with CL solution and CLs (balafilcon A). Cases were replaced monthly and collected at 1, 3, and 4 (for silver-impregnated cases only) months. Regular cases and the fourth-month silver-impregnated cases were maintained dry, and the other cases were maintained wet between uses. At collection, storage cases were sampled and cultured for microbial identification and enumeration. Ocular clinical findings, subjective responses to CL wear, and compliance were recorded at each visit. The percentages of microbial contamination for silver-impregnated and regular cases were 71% and 82% respectively. There were significantly (P < 0.005) fewer organisms in silver-impregnated cases (1.7 log CFU per well) than in regular cases (4.1 log CFU per well). In particular, silver-impregnated cases showed lower levels of Gram-negative bacteria (P = 0.04), Gram-positive bacilli (P = 0.03), and fungi (P = 0.006). Maintaining the silver-impregnated cases wet resulted in a lower percentage of contamination (71%; P < 0.01) than maintaining them dry (94%). There was no association between any clinical signs, symptoms, or compliance and microbial contamination of storage cases. More than 70% of the storage cases used in daily wear CL care for a month was contaminated irrespective of the types of cases. However, silver-impregnated cases were colonized by reduced levels of Gram-negative bacteria.

  18. Carbon Nanotube-Enhanced Carbon-Phenenolic Ablator Material (United States)

    Kikolaev, P.; Stackpoole, M.; Fan, W.; Cruden, B. A.; Waid, M.; Moloney, P.; Arepalli, S.; Arnold, J.; Partridge, H.; Yowell, L.


    This viewgraph presentation reviews the use of PICA (phenolic impregnated carbon ablator) as the selected material for heat shielding for future earth return vehicles. It briefly reviews the manufacturing of PICA and the advantages for the use of heat shielding, and then explains the reason for using Carbon Nanotubes to improve strength of phenolic resin that binds carbon fibers together. It reviews the work being done to create a carbon nanotube enhanced PICA. Also shown are various micrographic images of the various PICA materials.

  19. The Insulation Properties of Oil-Impregnated Insulation Paper Reinforced with Nano-TiO2


    Ruijin Liao; Cheng Lv; Lijun Yang; Yiyi Zhang; Weiqiang Wu; Chao Tang


    Oil-impregnated insulation paper has been widely used in transformers because of its low cost and desirable physical and electrical properties. However, research to improve the insulation properties of oil-impregnated insulation paper is rarely found. In this paper, nano-TiO2 was used to stick to the surface of cellulose which was used to make insulation paper. After oil-impregnated insulation paper reinforced by nano-TiO2 was prepared, the tensile strength, breakdown strength, and dielectric...


    Directory of Open Access Journals (Sweden)

    A. A. Ennan


    Full Text Available The present review is dedicated to the analysis of scientific works carried out in Physico- Chemical Institute of Environment and Human Protection (Odessa, Ukrainie and directed to the development of import-substituting sorption-filtering materials for respiratory purposes – impregnated fibrous chemisorbents (IFCS of acid gases, which are manufactured using standard equipment, as well as affordable and inexpensive chemical reagents and carriers of domestic origin. The process of chemisorption of sulphur dioxide by hexamethylenetetramine (HMTA modified nonwoven fibrous material resulted acid-catalyzed hydrolysis of HMTA to form aminomethanesulfonic acid and toxic formaldehyde. The IFCS with HMTA carried was recommended to use for air purification only from SiF4, HF, HCl and Cl2. Chemisorption of sulphur dioxide by fibrous materials impregnated by ethanolamines (monoethanolamine, diethanomamine, triethanomamine and N-methylethanolamine and polyethylenepolyamine (PEPA occurs only in the presence of “free” water with formation of “onium” sulphites, hydrosulphites and pyrosulphites. IFCS-PEPA (dynamic activity is 1,38 mmol(SO2/g are not inferior to the protective characteristics of IFCS with Na2CO3, HMTA, ethanolamines and the best foreign ionexchange fibrous chemisorbents brand VION and FIBAN (dynamic activity is 0,263 ÷0,422 mmol(SO2/g under conditions of respirators actual use (jAGM = 60 ÷ 90 %, TAGM = 297 K, VAGM = 2,0 sm/s, СSO2 = 20 ÷ 1000 mg/g3, QPEPA = 3,45 mmol/g. It is recommended to use the condensation products of primary alkylamines with formaldehyde (with large molar masses than the bases, complex compounds of amines with 3d-metals (Ni(II and Cu(II, salts of amine with aminoacids (glycine and polybasic acids (orthophosphoric acid (pKa1 = 2,12 and citric acid (pKa1 = 3,13 for manufacturing of IFCS of acid gases The IFCS with indication of dynamic absorptive capacity “wearing” (IVKS-I was developed.

  1. Investigation of alternative materials for impregnation of $Nb_{3}$ Sn magnets

    CERN Document Server

    Chichili, D R; Zlobin, A V


    Insulation is one of the most important elements of magnet design, which determines the electrical, mechanical, and thermal performance as well as lifetime of the magnet. The exposure to high radiation loads especially for the proposed LHC second-generation interaction region Nb/sub 3/Sn quadrupoles further limits the choices of the insulation materials. Traditionally Nb/sub 3/Sn magnets were impregnated with epoxy to improve both the mechanical and electrical properties. However, the acceptable radiation limit for epoxy is low which reduces the lifetime of the magnet. The paper presents the results of the feasibility study to replace epoxy with high radiation-resistant material during vacuum impregnation. The mechanical, thermal and electrical properties of samples impregnated with Matrimid were measured and compared with epoxy-impregnated samples. (9 refs).

  2. Strength and durability of concrete modified by sulfur-based impregnating compounds

    Directory of Open Access Journals (Sweden)

    MASSALIMOV Ismail Alexandrovich


    Full Text Available The aim of the research was to determine how sulfur-containing compound impregnation influences on concrete compressive strength and the impact resistance of concrete tiles. The results of these studies indicate that impregnation of vibropressed concrete paving tiles and concrete samples of dif-ferent strength classes with aqueous solutions based on calcium polysulfide leads to a significant increase of compressive strength and impact resistance. These data show that the strength of the products can be controlled by varying duration and frequency of the impregnation and by using pre-vacuum method. Impregnation with a solution of calcium polysulfide density of 1,23 g/cm³ can be recommended to increase strength of concrete products that are exposed to intense hydration and mechanical stress.

  3. A Mathematical Model of Repeated Impregnation of Porous Bodies with Solutions of Polymers

    Directory of Open Access Journals (Sweden)

    I. V. Glebov


    Full Text Available The paper describes basic methods of impregnating porous bodies with solutions of polymers and their use to manufacture prepregs. It also describes the existing methods of manufacturing multilayer prepregs to produce aerospace coating of the spacecraft "Soyuz". It is shown that these prepregs have to meet high requirements for the content of the polymer, as compared with other composite materials, about 35 - 40% of the mass. Methods used for their manufacturing are long-term and non-controllable. The assumption is made that using the vacuum impregnation technology of a woven material will allow to accelerate the manufacturing process of these prepregs and improve their quality.In reviewing the technical literature have been found works on modeling the processes of impregnation, but they are aimed only at studying the speed of the woven material impregnation by various fluids and determining the time of impregnation. There were no models found to define prepreg parameters during the process of multiple impregnations. The aim of this work is to develop the simple mathematical model, which enables us to predict the polymer content of volatile products in the prepreg after each cycle of multiple impregnation of woven material with a solution of the polymer.To consider the vacuum impregnation method are used the prepregs based on silica and silica-nylon stitch-bonding fabric and bakelite varnish LBS-4 containing 50 - 60% of phenol resin and the solvent with minor impurities of pure phenol and water, as an example. To describe the process of vacuum impregnation of the porous work-piece is developed a mathematical description of the process of filling the porous space of the material with a varnish. It is assumed that the varnish components fill the porous space of the material in the same proportion as they are contained in the varnish.It is shown that a single impregnation cannot ensure the content of phenol resin in the prepreg over 32%, which does

  4. Advanced Examination Techniques Applied to the Assessment of Vacuum Pressure Impregnation (VPI) of ITER Correction Coils

    CERN Document Server

    Sgobba, Stefano; Samain, Valerie; Libeyre, Paul; Cecillon, Alexandre; Dawid, J


    The ITER Magnet System includes a set of 18 superconducting correction coils (CC) which are used to compensate the error field modes arising from geometrical deviations caused by manufacturing and assembly tolerances. The turn and ground insulation are electrically insulated with a multi-layer fiberglass polyimide interleaved composite, impregnated with epoxy resin using vacuum pressure impregnation (VPI). Adequate high voltage insulation (5 kV), mechanical strength and rigidity of the winding pack should be achieved after impregnation and curing of the insulation system. VPI is an effective process to avoid defects such dry spots and incomplete wet out. This insulation technology has also been developed since several years for application to large superconducting coils and more recently to ITER CC. It allows the coils to be impregnated without impacting on their functional characteristics. One of the critical challenges associated with the construction of the CC is the qualification of the VPI insulation. Se...

  5. Technology for improving the wear resistance of aggregates by materials impregnation (United States)


    The use of impregnation as a means of improving the wear resistance of natural aggregates was investigated. A series of tests were conducted using four aggregates of varying quality, selected from a sampling of 40 different aggregates. Tests performe...

  6. Effects of impregnated metal ions on air/CO2-gasification of woody biomass. (United States)

    Hurley, Scott; Li, Hanning; Xu, Chunbao Charles


    Several impregnated metal ions (Fe (III), Co (II), Ni (II), and Ru (IV)) and a raw iron ore (natural limonite) were examined as catalysts for gasification of pine sawdust in air/CO(2) at 700 and 800 degrees C. The yields of char and tar both increased with increasing CO(2) content in the feed gas. All the impregnated metal ions, in particular Ni (II), Co (II) and Ru (IV), were very effective for promoting biomass gasification in CO(2), leading to greatly reduced yields of tar and char accompanied by significantly enhanced formation of CO and H(2). At 800 degrees C, the impregnation of Fe (III), Ni (II), Co (II) or Ru (IV) led to almost complete conversion of the solid biomass into gas/liquid products, producing an extremely low char yield (tar yield reduced from 32.1 wt.% without catalyst to 19-27 wt.% with the impregnated metal ions. 2010 Elsevier Ltd. All rights reserved.

  7. Oxidative dehydration of glycerol to acrylic acid over vanadium-impregnated zeolite beta

    Energy Technology Data Exchange (ETDEWEB)

    Pestana, Carolina F.M.; Guerra, Antonio C.O.; Turci, Cassia C. [Universidade Federal do Rio de Janeiro, RJ (Brazil). Inst. de Quimica; Ferreira, Glaucio B. [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Inst. de Quimica; Mota, Claudio J.A., E-mail: [INCT Energia e Ambiente, Universidade Federal do Rio de Janeiro, RJ (Brazil)


    The oxidative dehydration of glycerol to acrylic acid was studied over vanadium-impregnated zeolite Beta. Catalysts were prepared by wet impregnation of ammonium metavanadate over ammonium-exchanged zeolite Beta, followed by air calcination at 823 K. Impregnation reduced the specific surface area, but did not significantly affected the acidity (Bronsted and Lewis) of the zeolites. The catalytic evaluation was carried out in a fixed bed flow reactor using air as the carrier and injecting glycerol by means of a syringe pump. Acrolein was the main product, with acetaldehyde and hydroxy-acetone (acetol) being also formed. Acrylic acid was formed with approximately 25% selectivity at 548 K over the impregnated zeolites. The result can be explained by XPS (X-ray photoelectron spectroscopy) measurements, which indicated a good dispersion of the vanadium inside the pores. (author)

  8. Theoretical impact of insecticide-impregnated school uniforms on dengue incidence in Thai children

    National Research Council Canada - National Science Library

    Massad, Eduardo; Amaku, Marcos; Coutinho, Francisco Antonio Bezerra; Kittayapong, Pattamaporn; Wilder-Smith, Annelies


    ...; hence strategies that reduce human-mosquito contact to protect against the day-biting habits of Aedes mosquitoes at schools, such as insecticide-impregnated uniforms, could be an effective prevention strategy...

  9. Olive fruits and vacuum impregnation, an interesting combination for dietetic iron enrichment

    National Research Council Canada - National Science Library

    Zunin, Paola; Turrini, Federica; Leardi, Riccardo; Boggia, Raffaella


    In this study vacuum impregnation (VI) was employed for the iron enrichment of olive fruits, which are very interesting as food vehicle for VI mineral supplementation for the porosity of their pulp...

  10. Research Data Supporting "Impregnation and encapsulation of lightweight aggregates for self-healing concrete"


    Alghamri, R.; Kanellpoulos, A.; Al-Tabbaa, A.


    The data supports the findings and discussion on the field of impregnation and encapsulation of lightweight aggregates for self-healing concrete. Yousef Jameel Foundation through Cambridge Commonwealth, European & International Trust

  11. Expression, Purification and Characterization of GMZ2'.10C, a Complex Disulphide-Bonded Fusion Protein Vaccine Candidate against the Asexual and Sexual Life-Stages of the Malaria-Causing Plasmodium falciparum Parasite

    NARCIS (Netherlands)

    Mistarz, U.H.; Singh, S.K; Nguyen, T.; Roeffen, W.; Lissau, C.; Madsen, S.M.; Vrang, A.; Tiendrebeogo, R.W.; Kana, I.H.; Sauerwein, R.W.; Theisen, M.; Rand, K.D.


    PURPOSE: Production and characterization of a chimeric fusion protein (GMZ2'.10C) which combines epitopes of key malaria parasite antigens: glutamate-rich protein (GLURP), merozoite surface protein 3 (MSP3), and the highly disulphide bonded Pfs48/45 (10C). GMZ2'.10C is a potential candidate for a

  12. The Effects of Natural Weathering on Color Stability of Impregnated and Varnished Wood Materials


    Turkay Turkoglu; Ergun Baysal; Hilmi Toker


    The aim of this study was to investigate effects of natural weathering on color stability of Scots pine (Pinus sylvestris L.) and Oriental beech (Fagus orientalis L.) impregnated with some chemicals [tanalith-E (TN-E), adolit-KD5 (AD-KD5), and chromated copper arsenate (CCA)] and then varnished [synthetic varnish (SV) and polyurethane varnish (PV)]. While applying varnish increased lightness, impregnation decreased lightness of the wood specimens before natural weathering. Natural weathering ...

  13. The Insulation Properties of Oil-Impregnated Insulation Paper Reinforced with Nano-TiO2

    Directory of Open Access Journals (Sweden)

    Ruijin Liao


    Full Text Available Oil-impregnated insulation paper has been widely used in transformers because of its low cost and desirable physical and electrical properties. However, research to improve the insulation properties of oil-impregnated insulation paper is rarely found. In this paper, nano-TiO2 was used to stick to the surface of cellulose which was used to make insulation paper. After oil-impregnated insulation paper reinforced by nano-TiO2 was prepared, the tensile strength, breakdown strength, and dielectric properties of the oil-impregnated insulation paper were investigated to determine whether the modified paper had a better insulation performance. The results show that there were no major changes in tensile strength, and the value of the breakdown strength was greatly improved from 51.13 kV/mm to 61.78 kV/mm. Also, the values of the relative dielectric constant, the dielectric loss, and conductivity declined. The discussion reveals that nano-TiO2 plays a major role in the phenomenon. Because of the existence of nano-TiO2, the contact interface of cellulose and oil was changed, and a large number of shallow traps were produced. These shallow traps changed the insulation properties of oil-impregnated insulation paper. The results show that the proposed solution offers a new method to improve the properties of oil-impregnated insulation paper.

  14. Effects of impregnation methods and drying conditions on quinoline hydrodenitrogenation over Ni-W based catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Fang; Qiu, Zegang; Zhao, Liangfu; Xiang, Hongwei [Institute of Coal Chemistry, Chinese Academy of Sciences (China); Guo, Shaoqing [Taiyuan University of Science and Technology (China)


    The effects of impregnation methods (co-impregnation and sequential impregnation) and drying conditions (air and vacuum) on the structure and catalytic behavior of MCM-41 supported Ni-W catalysts were investigated. The catalysts were characterized by powder X-ray diffraction (XRD) analysis, Fourier-transform infrared spectroscopy (FT-IR), diffuse reflectance UV-Vis absorbance spectroscopy (DRS), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and pyridine adsorbed infrared spectroscopy (Py-IR) techniques. They were tested for hydrodenitrogenation (HDN) of quinoline at temperatures of 300-400 deg C. The HDN results showed that the catalysts prepared by co-impregnation were more active than the catalysts prepared by sequential impregnation and the catalysts prepared by drying under vacuum were more active than the catalysts dried in air. Characterization revealed that the co-impregnation method and drying under vacuum promoted the dispersion of W, the formation of the active phases, and the formation of acidic sites on the catalysts. (author)


    National Research Council Canada - National Science Library

    Karen Peña; Liliana Giraldo; Juan Carlos Moreno


      Activated carbons are prepared by pyrolysis of orange peel, lignocellulosic wastes by chemical activation by impregnation with phosphoric acid at different concentrations (32 %, 36 %, 40 % and 48 % w/V...

  16. Production and characterization of activated carbon from a ...

    African Journals Online (AJOL)

    In this study, the use of a bituminous coal for the production of activated carbons with chemical activation was investigated. The effects of process variables such as chemical reagents, activation temperature, impregnation ratio and carbonization temperature were investigated to optimize these parameters. The resultant ...

  17. Gene design, fusion technology and TEV cleavage conditions influence the purification of oxidized disulphide-rich venom peptides in Escherichia coli. (United States)

    Sequeira, Ana Filipa; Turchetto, Jeremy; Saez, Natalie J; Peysson, Fanny; Ramond, Laurie; Duhoo, Yoan; Blémont, Marilyne; Fernandes, Vânia O; Gama, Luís T; Ferreira, Luís M A; Guerreiro, Catarina I P I; Gilles, Nicolas; Darbon, Hervé; Fontes, Carlos M G A; Vincentelli, Renaud


    Animal venoms are large, complex libraries of bioactive, disulphide-rich peptides. These peptides, and their novel biological activities, are of increasing pharmacological and therapeutic importance. However, recombinant expression of venom peptides in Escherichia coli remains difficult due to the significant number of cysteine residues requiring effective post-translational processing. There is also an urgent need to develop high-throughput recombinant protocols applicable to the production of reticulated peptides to enable efficient screening of their drug potential. Here, a comprehensive study was developed to investigate how synthetic gene design, choice of fusion tag, compartment of expression, tag removal conditions and protease recognition site affect levels of solubility of oxidized venom peptides produced in E. coli. The data revealed that expression of venom peptides imposes significant pressure on cysteine codon selection. DsbC was the best fusion tag for venom peptide expression, in particular when the fusion was directed to the bacterial periplasm. While the redox activity of DsbC was not essential to maximize expression of recombinant fusion proteins, redox activity did lead to higher levels of correctly folded target peptides. With the exception of proline, the canonical TEV protease recognition site tolerated all other residues at its C-terminus, confirming that no non-native residues, which might affect activity, need to be incorporated at the N-terminus of recombinant peptides for tag removal. This study reveals that E. coli is a convenient heterologous host for the expression of soluble and functional venom peptides. Using the optimal construct design, a large and diverse range of animal venom peptides were produced in the µM scale. These results open up new possibilities for the high-throughput production of recombinant disulphide-rich peptides in E. coli.

  18. One-electron oxidation pathway of thiols by peroxynitrite in biological fluids: bicarbonate and ascorbate promote the formation of albumin disulphide dimers in human blood plasma. (United States)

    Scorza, G; Minetti, M


    Recent studies have shown that peroxynitrite oxidizes thiol groups through competing one- and two-electron pathways. The two-electron pathway is mediated by the peroxynitrite anion and prevails quantitatively over the one-electron pathway, which is mediated by peroxynitrous acid or a reactive species derived from it. In CO2-containing fluids the oxidation of thiols might follow a different mechanism owing to the rapid formation of a different oxidant, the nitrosoperoxycarbonate anion (ONOOCO2(-)). Here we present evidence that in blood plasma peroxynitrite induces the formation of a disulphide cross-linked protein identified by immunological (anti-albumin antibodies) and biochemical criteria (peptide mapping) as a dimer of serum albumin. The albumin dimer did not form in plasma devoid of CO2 and its formation was enhanced by ascorbate. However, analysis of thiol groups showed that reconstituting dialysed plasma with NaHCO3 protected protein thiols against the oxidation mediated by peroxynitrite and that the simultaneouspresence of ascorbate provided further protection. Ascorbate alone did not protect thiol groups from peroxynitrite-mediated oxidation. ESR spin-trapping studies with N-t-butyl-alpha-phenylnitrone (PBN) revealed that peroxynitrite induced the formation of protein thiyl radicals and their intensity was markedly decreased by plasma dialysis and restored by reconstitution with NaHCO3. PBN completely inhibited the formation of albumin dimer. Moreover, the addition of iron-diethyldithiocarbamate to plasma demonstrated that peroxynitrite induced the formation of protein S-nitrosothiols and/or S-nitrothiols. Our results are consistent with the hypothesis that NaHCO3 favours the one-electron oxidation of thiols by peroxynitrite with formation of thiyl radicals, ;NO2, and RSNOx. Thiyl radicals, in turn, are involved in chain reactions by which thiols are oxidized to disulphides. PMID:9425126

  19. The subtilisin-like protease AprV2 is required for virulence and uses a novel disulphide-tethered exosite to bind substrates.

    Directory of Open Access Journals (Sweden)

    Ruth M Kennan

    Full Text Available Many bacterial pathogens produce extracellular proteases that degrade the extracellular matrix of the host and therefore are involved in disease pathogenesis. Dichelobacter nodosus is the causative agent of ovine footrot, a highly contagious disease that is characterized by the separation of the hoof from the underlying tissue. D. nodosus secretes three subtilisin-like proteases whose analysis forms the basis of diagnostic tests that differentiate between virulent and benign strains and have been postulated to play a role in virulence. We have constructed protease mutants of D. nodosus; their analysis in a sheep virulence model revealed that one of these enzymes, AprV2, was required for virulence. These studies challenge the previous hypothesis that the elastase activity of AprV2 is important for disease progression, since aprV2 mutants were virulent when complemented with aprB2, which encodes a variant that has impaired elastase activity. We have determined the crystal structures of both AprV2 and AprB2 and characterized the biological activity of these enzymes. These data reveal that an unusual extended disulphide-tethered loop functions as an exosite, mediating effective enzyme-substrate interactions. The disulphide bond and Tyr92, which was located at the exposed end of the loop, were functionally important. Bioinformatic analyses suggested that other pathogenic bacteria may have proteases that utilize a similar mechanism. In conclusion, we have used an integrated multidisciplinary combination of bacterial genetics, whole animal virulence trials in the original host, biochemical studies, and comprehensive analysis of crystal structures to provide the first definitive evidence that the extracellular secreted proteases produced by D. nodosus are required for virulence and to elucidate the molecular mechanism by which these proteases bind to their natural substrates. We postulate that this exosite mechanism may be used by proteases produced by

  20. Efficiency of Silver Impregnated Porous Pot (SIPP) filters for production of clean potable water. (United States)

    Mahlangu, Oranso; Mamba, Bhekie; Momba, Maggie


    The Silver Impregnated Porous Pot (SIPP) filter is a product of the Tshwane University of Technology manufactured for the production of safe drinking water at a household (home) level. Two SIPP devices were assessed for the reduction efficiency of chemical contaminants such as calcium, magnesium, iron, arsenic, fluorides and total organic carbon (TOC) as well as microbial contaminants from environmental samples. Turbidity change after filtration, together with correlation between chlorophyll a in the feed water and SIPP's flow rates were also evaluated in order to give comprehensive guidelines on the quality of intake water that could be filtered through the filter without causing a significant decrease in flow rate. The SIPP filters removed contaminants from environmental water samples as follows: 70% to 92% iron, 36% to 68% calcium, 42% to 82% arsenic, 39% to 98% magnesium, 39% to 95% fluorides, 12% to 35% TOC and 45% to 82% turbidity. The SIPP filters had initial flow rates of 1 L/h to 4 L/h but the flow rates dropped to 0.5 L/h with an increase in cumulative volume of intake water as the filter was used. Turbidity and chemical contaminant reduction rates decreased with accumulating volume of intake water but the filter removed Ca, Fe and Mg to levels that comply with the South African National Standards (SANS 241) and the World Health Organization (WHO) guideline values. However, the SIPP filters cannot produce enough water to satisfy the daily drinking water requirement of a typical household (25 L/p·d). Chlorophyll a was associated with a decrease in the flow rate through the SIPP filters.

  1. Efficiency of Silver Impregnated Porous Pot (SIPP Filters for Production of Clean Potable Water

    Directory of Open Access Journals (Sweden)

    Bhekie Mamba


    Full Text Available The Silver Impregnated Porous Pot (SIPP filter is a product of the Tshwane University of Technology manufactured for the production of safe drinking water at a household (home level. Two SIPP devices were assessed for the reduction efficiency of chemical contaminants such as calcium, magnesium, iron, arsenic, fluorides and total organic carbon (TOC as well as microbial contaminants from environmental samples. Turbidity change after filtration, together with correlation between chlorophyll a in the feed water and SIPP’s flow rates were also evaluated in order to give comprehensive guidelines on the quality of intake water that could be filtered through the filter without causing a significant decrease in flow rate. The SIPP filters removed contaminants from environmental water samples as follows: 70% to 92% iron, 36% to 68% calcium, 42% to 82% arsenic, 39% to 98% magnesium, 39% to 95% fluorides, 12% to 35% TOC and 45% to 82% turbidity. The SIPP filters had initial flow rates of 1 L/h to 4 L/h but the flow rates dropped to 0.5 L/h with an increase in cumulative volume of intake water as the filter was used. Turbidity and chemical contaminant reduction rates decreased with accumulating volume of intake water but the filter removed Ca, Fe and Mg to levels that comply with the South African National Standards (SANS 241 and the World Health Organization (WHO guideline values. However, the SIPP filters cannot produce enough water to satisfy the daily drinking water requirement of a typical household (25 L/p·d. Chlorophyll a was associated with a decrease in the flow rate through the SIPP filters.

  2. Durability of Pinus elliottii Wood Impregnated with Quebracho Colorado (Schinopsis balansae) Bio-Protectives Extracts and CCA


    Bernardi,Aldo C; Popoff, Orlando


    Some wood preservatives have a warning due to environmental restrictions and risks to man health. The aim of this study is to determine the performance of non impregnated and impregnated wood with a CCA salt and a bio-protective made from "quebracho colorado", when facing the action of fungi responsible for white rot decay by Pycnoporus sanguineus and brown rot attack by Gloeophyllum sepiarium. Wood samples were impregnated with different solutions by vacuum-pressure method. The design was in...

  3. Silicon Composite Anode Materials for Lithium Ion Batteries Based on Carbon Cryogels and Carbon Paper (United States)

    Woodworth, James; Baldwin, Richard; Bennett, William


    A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nanofoams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

  4. Carbon Cryogel and Carbon Paper-Based Silicon Composite Anode Materials for Lithium-Ion Batteries (United States)

    Woodworth, James; Baldwin, Richard; Bennett, William


    A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 6 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-5 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

  5. Cryogenic properties of epoxy resins applied for matrix or impregnating materials; Epokishikei matorikkusu mataha ganshizai no gokuteion tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Kashima, T.; Yamanaka, A.; Takasugi, T. [Toyobo, Ltd., Osaka (Japan); Wake, M.; Nakayama, S. [High Energy Accelerator Research Organization, Tsukuba (Japan); Sugawara, K. [Ship and Ocean Foundation, Tokyo (Japan)


    We use the epoxy resin as matrix of the FRP and impregnant for the conductor fixation of superconducting coil used in the very low temperature field. However, we have not always clarified the relationship between low-temperature dependence of the FRP and stability of the coil and impregnation-ness of epoxy and resin composition. We examined impregnation-ness for ultra-high powerful polyethylene fiber and Nb{sub 3}Sn conductor using epoxy of the composition, which differed in this paper variously, and the cold-resistance of the FRP and impregnation conductor was examined. (NEDO)

  6. NOx conversion on LSM15-CGO10 cell stacks with BaO impregnation

    DEFF Research Database (Denmark)

    Traulsen, Marie Lund; Andersen, Kjeld Bøhm; Kammer Hansen, Kent


    The electrochemical conversion of NOx on non-impregnated and BaO-impregnated LSM15-CGO10 (La0.85Sr0.15MnO3-Ce0.9Gd0.1O1.95) porous cell stacks has been investigated, and extensive impedance analysis have been performed to identify the effect of the BaO on the electrode processes. The investigation...... was conducted in the temperature range 300-500 degrees C, a polarisation range from 3 V to 9 V and in atmospheres containing 1000 ppm NO, 1000 ppm NO + 10% O-2 and 10% O-2. On the non-impregnated cell stacks no NOx conversion was observed under any of the investigated conditions. However, BaO impregnation...... greatly enhanced the NOx conversion and at 400 degrees C and 9 V polarisation a BaO-impregnated cell stack showed 60% NOx conversion into N-2 with 8% current efficiency in 1000 ppm NO + 10% O-2. This demonstrates high NOx conversion can be achieved on an entirely ceramic cell without expensive noble...

  7. Molecular dimensions and surface diffusion assisted mechanically robust slippery perfluoropolyether impregnated mesoporous alumina interfaces (United States)

    Rowthu, Sriharitha; Balic, Edin E.; Hoffmann, Patrik


    Accomplishing mechanically robust omniphobic surfaces is a long-existing challenge, and can potentially find applications in bioengineering, tribology and paint industries. Slippery liquid impregnated mesoporous α-Al2O3 interfaces are achieved with water, alkanes, water based and oil based high viscosity acrylic paints. Incredibly high abrasion-resistance (wear coefficients ≤10‑8 mm3 N‑1 m‑1) and ultra-low friction coefficients (≥0.025) are attained, attributing to the hard alumina matrix and continuous replenishment of perfluoropolyether aided by capillarity and surface diffusion processes. A variety of impregnating liquids employed suggest that large molecules, faster surface diffusion and lowest evaporation rate generate the rare combination of high wear-resistance and omniphobicity. It is noteworthy that these novel liquid impregnated Al2O3 composites exhibit outstanding load bearing capacity up to 350 MPa; three orders of magnitude higher than achievable by the state of the art omniphobic surfaces. Further, our developed thermodynamic calculations suggest that the relative thermodynamic stability of liquid impregnated composites is linearly proportional to the spreading coefficient (S) of the impregnating liquid with the matrix material and is an important tool for the selection of an appropriate matrix material for a given liquid.

  8. Adsorptive desulfurization of kerosene and diesel oil by Zn impregnated montmorollonite clay

    Directory of Open Access Journals (Sweden)

    Waqas Ahmad


    Full Text Available In the present research work, desulfurization of kerosene and diesel oil has been carried out by selective adsorption through metals impregnated montmorollonite clay (MMT. Different metals were impregnated on MMT by wet impregnation method which included Fe, Cr, Ni, Co, Mn, Pb, Zn and Ag. The adsorption study was carried out in batch operation initially for 1 h time and at room temperature (25 °C. The results show that high desulfurization was brought about by Zn-MMT. In the case of kerosene highest desulfurization of 76% and in the case of diesel maximum desulfurization of 77% was achieved with adsorption through Zn-MMT. Conditions were also optimized for the desulfurization process. Highest yield of desulfurization was obtained at 1-h stirring period, at room temperature (25 °C and using oil to adsorbent ratio of 20:1.5. Under optimized conditions the adsorbent was found to adsorb about 81% of DBT from the model oil containing 1000 ppm DBT dissolved in cyclohexane. EDX, Surface characterization and SEM analysis of the adsorbents used in the study were conducted to evaluate their mineralogical nature and textural behavior. Results show that the surface area, pore size and pore volume of the MMT has been found to be increased many fold with Zn impregnation. Also the surface morphology of the MMT has also been improved with Zn impregnation.

  9. Sorption and desorption of chromate by wood shavings impregnated with iron or aluminum oxide. (United States)

    Kuo, S; Bembenek, R


    This study examined the impregnation of hybrid poplar shavings with Fe or Al oxide and their reactivity with Cr(VI). The shavings were impregnated with an average of 1.24+/-0.18 mmol Fe g(-1) or 1.51+/-0.17 mmol Al g(-1), and the impregnated Fe or Al oxide was highly amorphous. Capacity of Cr(VI) sorption by impregnated shavings was high and rate of the sorption was rapid. While the freshly sorbed Cr on the Fe oxide-shavings was readily desorbed in 0.1M NaOH, nine weeks of ageing reduced the desorbability to only 6.5% of the sorbed Cr. Extraction with 0.1M NaOH remained feasible to recover most sorbed Cr from the Al oxide-shavings over the same ageing period. Impregnation of the shavings with Fe or Al oxide turns the wood waste into a product for removing Cr(VI) or other oxyanions from wastewater.

  10. Incorporation of Hyperbranched Supramolecules into Nafion Ionic Domains via Impregnation and In-Situ Photopolymerization

    Directory of Open Access Journals (Sweden)

    Hiruto Kudo


    Full Text Available Nafion membranes were impregnated with photocurable supramolecules, viz., hyperbranched polyester having pendant functional carboxylic acid groups (HBPEAc-COOH by swelling in methanol and subsequently photocured in-situ after drying. Structure-property relationships of the HBPEAc-COOH impregnated Nafion membranes were analyzed on the basis of Fourier transform infrared (FTIR spectroscopy, solid-state nuclear magnetic resonance (SSNMR and dynamic mechanical analysis (DMA. FTIR and SSNMR investigations revealed that about 7 wt % of HBPEAc-COOH was actually incorporated into the ionic domains of Nafion. The FTIR study suggests possible complexation via inter-species hydrogen bonding between the carboxylic groups of HBPEAc-COOH and the sulfonate groups of Nafion. The α-relaxation peak corresponding to the glass transition temperature of the ionic domains of the neat Nafion-acid form was found to increase from ~100 to ~130 °C upon impregnation with enhanced modulus afforded by the cured polyester network within the ionic domains. The AC impedance fuel cell measurement of the impregnated membrane exhibited an increasing trend of proton conductivity with increasing temperature, which eventually surpassed that of neat Nafion above 100 °C. Of particular importance is that the present paper is the first to successfully incorporate polymer molecules/networks into the Nafion ionic domains by means of impregnation with hyperbranched supramolecules followed by in-situ photopolymerization.

  11. Controllable Impregnation Via Inkjet Printing for the Fabrication of Solid Oxide Cell Air Electrodes

    KAUST Repository

    Da'as, E. H.


    The impregnation method has been considered as one of the most successful techniques for the fabrication of highly efficient electrodes for solid oxide fuel and electrolysis cells (SOCs) at the lab scale. However, because the impregnation is usually performed manually, its irreproducibility remains a major problem that can be solved by using controllable techniques, such as inkjet printing. In this paper, lanthanum strontium manganite (LSM)/yttria stabilized zirconia (YSZ) air electrodes were prepared by infiltrating YSZ porous bodies with LSM precursor solution using inkjet printing, followed by annealing at 800°C for 2 hours. XRD analysis confirmed the formation of the LSM phase, which was in the form of nanoparticles with size in the 50-70 nm range on the YSZ walls, as revealed by FEG-SEM observations. The effect of printing parameters on the distribution of the impregnated phase was investigated and discussed.

  12. Development of nitrocellulose membrane filters impregnated with different biosynthesized silver nanoparticles applied to water purification. (United States)

    Fernández, Jorge G; Almeida, César A; Fernández-Baldo, Martín A; Felici, Emiliano; Raba, Julio; Sanz, María I


    Bactericidal water filters were developed. For this purpose, nitrocellulose membrane filters were impregnated with different biosynthesized silver nanoparticles. Silver nanoparticles (AgNPs) from Aspergillus niger (AgNPs-Asp), Cryptococcus laurentii (AgNPs-Cry) and Rhodotorula glutinis (AgNPs-Rho) were used for impregnating nitrocellulose filters. The bactericidal properties of these nanoparticles against Escherichia coli, Enterococcus faecalis and Pseudomona aeruginosa were successfully demonstrated. The higher antimicrobial effect was observed for AgNPs-Rho. This fact would be related not only to the smallest particles, but also to polysaccharides groups that surrounding these particles. Moreover, in this study, complete inhibition of bacterial growth was observed on nitrocellulose membrane filters impregnated with 1 mg L(-1) of biosynthesized AgNPs. This concentration was able to reduce the bacteria colony count by over 5 orders of magnitude, doing suitable for a water purification device. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Elution of platinum from carboplatin-impregnated calcium sulfate hemihydrate beads in vitro. (United States)

    Tulipan, Rachel J; Phillips, Heidi; Garrett, Laura D; Dirikolu, Levent; Mitchell, Mark A


    OBJECTIVE To characterize the elution of platinum from carboplatin-impregnated calcium sulfate hemihydrate (CSH) beads in vitro. SAMPLE 60 carboplatin-impregnated CSH beads and 9 CSH beads without added carboplatin (controls). PROCEDURES Carboplatin-impregnated CSH beads (each containing 4.6 mg of carboplatin [2.4 mg of platinum]) were placed into separate 10-mL plastic tubes containing 5 mL of PBSS in groups of 1, 3, 6, or 10; 3 control beads were placed into a single tube of PBSS at the same volume. Experiments were conducted in triplicate at 37°C and a pH of 7.4 with constant agitation. Eluent samples were collected at 1, 2, 3, 6, 12, 24, and 72 hours. Samples were analyzed for platinum content by inductively coupled plasma-mass spectrometry. RESULTS The mean concentration of platinum released per carboplatin-impregnated bead over 72 hours was 445.3 mg/L. Cumulative concentrations of platinum eluted increased as the number of beads per tube increased. There was a significant difference in platinum concentrations over time, with values increasing over the first 12 hours and then declining for all tubes. There was also a significant difference in percentage of total incorporated platinum released into tubes with different numbers of beads: the percentage of eluted platinum was higher in tubes containing 1 or 3 beads than in those containing 6 or 10 beads. CONCLUSIONS AND CLINICAL RELEVANCE Carboplatin-impregnated CSH beads eluted platinum over 72 hours. Further studies are needed to determine whether implantation of carboplatin-impregnated CSH beads results in detectable levels of platinum systemically and whether the platinum concentrations eluted locally are toxic to tumor cells.

  14. Characterization of impregnated GDC nano structures and their functionality in LSM based cathodes

    DEFF Research Database (Denmark)

    Klemensø, Trine; Chatzichristodoulou, Christodoulos; Nielsen, Jimmi


    Porous composite cathodes of LSM–YSZ (lanthanum strontium manganite and yttria stabilized zirconia) were impregnated with GDC (gadolinia doped ceria) nano particles. The impregnation process was varied using none or different surfactants (Triton X-45, Triton X-100, P123), and the quantity...... on the LSM phase and the LSM grain boundaries. The observations suggest that the improved performance associated with GDC nano particles is related to the particles placed near the TPB (triple phase boundary) zone. The GDC extends the TPB by creating an ionic conducting network on top of the LSM particles...

  15. Impact of KCl impregnation on single particle combustion of wood and torrefied wood

    DEFF Research Database (Denmark)

    Lu, Zhimin; Jian, Jie; Jensen, Peter Arendt


    In this work, single particle combustion of raw and torrefied 4 mm wood particles with different potassium content obtained by KCl impregnation and washing was studied experimentally under a condition of 1225 °C, 3.1% O2 and 26.1% H2O. The ignition time and devolatilization time depended almost......, and unchanged by torrefaction. Compared to the raw wood particle, the char conversion time was increased by torrefaction, decreased by washing, and almost unchanged by KCl impregnation due to its promoting effect on both char yield and reactivity....

  16. A Combined Electro-Thermal Breakdown Model for Oil-Impregnated Paper

    Directory of Open Access Journals (Sweden)

    Meng Huang


    Full Text Available The breakdown property of oil-impregnated paper is a key factor for converter transformer design and operation, but it is not well understood. In this paper, breakdown voltages of oil-impregnated paper were measured at different temperatures. The results showed that with the increase of temperature, electrical, electro-thermal and thermal breakdown occurred successively. An electro-thermal breakdown model was proposed based on the heat equilibrium and space charge transport, and negative differential mobility was introduced to the model. It was shown that carrier mobility determined whether it was electrical or thermal breakdown, and the model can effectively explain the temperature-dependent breakdown.

  17. A Binder Viscosity Effect on the Wet-Wounded Composite Porosity in the Impregnating Bath

    Directory of Open Access Journals (Sweden)

    M. A. Komkov


    Full Text Available The aim of this work is to define experimentally an impregnation rate of VM-1 glass fibers and CBM aramid bundles with the epoxy binder EDB-10 using wet method of winding. During the impregnation process of the fibrous fillers by the liquid binder, air is displaced from the interfiber space of fiber and bundle. With the composite product winding a fiber impregnation process is short. That is why gas inclusions or pores are formed in the polymer-fiber compositeThe impregnation rate or porosity of wound material will depend directly on the binder viscosity. To reduce an epoxy binder viscosity temporarily is possible by two ways. The first is to heat a liquid epoxy composition EDB-10 to the maximum possible temperature during the winding process of the product. The second method is to dilute the binder by a solvent, such as acetone or alcohol. However, the solvent reduces its strength.The paper presents experimental data to show the volumetric content of pores in the wound composite affected only by the viscosity of the epoxy binder. Heating a binder allowed us to regulate a changing conditional viscosity of the binder in the impregnating bath for the normal conditions of impregnation. Other impacts on the impregnation and filament-winding processes, such as filler kinks, squeeze, vacuuming binder, highly tensioned winding, and others were not used.Experimentally obtained dependences of the porosity value of wound composite on the conditional viscosity of binder are nonlinear and can be used to design heaters for impregnating devices of winders. The research technique and results can be used in development of technological processes to manufacture composite structures by winding from the other reinforcing fibrous fillers and thermo-active binders.The results show that the volumetric content of pores can significantly vary within 8 - 14 % of material volume. Therefore, to reduce the number of pores in the wound composite to 1-2 %, auxiliary

  18. The effect of type and mixture of resin on the properties of impregnated paper


    hossein Kermanian; sedigheh rafiei; esmaeil Rasooly Garmaroody3; omid ramezani


    This study was carried out in order to investigate the effects of different types of resins and also their mixtures on the impregnated paper properties. In this regard, pure urea resin (100%), mixture of melamine and urea resins with various combinations (60/40 and 70/30 and 50/50), mixture of nano-fiber cellulose ratios of 1, 2 and 3 percent with urea resin and pure PVA (100%) were used to impregnate of newsprint basic paper of Mazandaran wood and paper industries. Immersion of samples in th...

  19. Out-of-Plane Self-Propulsion of Droplets on Heated Lubricant-Impregnated Surfaces (United States)

    Dash, Susmita; de Ruiter, Jolet; Varanasi, Kripa


    In this work, we investigate droplet motion on lubricant-impregnated surfaces that are stable at high temperatures. Water droplets on such surfaces demonstrate in-plane hopping motion and out-of-plane self-propulsion at temperatures far below the typical Leidenfrost temperatures. While the in-plane motion of the droplet is on the order of 10 mm/s, the droplet is propelled vertically upwards at a velocity of approximately 200 mm/s. We present the mechanics underlying this behavior of droplets, which is specific to lubricant-impregnated surfaces.

  20. Protection from avian influenza H5N1 virus infection with antibody-impregnated filters

    Directory of Open Access Journals (Sweden)

    Tsukamoto Masaya


    Full Text Available Abstract There is worldwide concern over the possibility of a new influenza pandemic originating from the highly pathogenic avian H5N1 influenza viruses. We herein demonstrate that functional air filters impregnated with ostrich antibodies against the hemagglutinin of the H5N1 virus protect chickens from death by H5N1 transmission. These results suggest that the use of ostrich antibody-impregnated filters might be a powerful way to prevent the transmission of H5N1.

  1. Influence of impregnation by inorganic substances on the yield of pyrolysis products

    Energy Technology Data Exchange (ETDEWEB)

    Shevkoplyas, V.N.; Saranchuk, V.I. [AN Ukrainskoj SSR, Donetsk (Ukraine). Inst. Fiziko-Organicheskoj Khimii i Uglekhimii


    In papers was shown that fossil coals impregnation by aqueous solution of inorganic substances with a subsequent pyrolysis leads to the rise of the rate and depth of its organic mass destruction into liquid and gaseous products. This is, apperently, conditioned by changes in coals structure already on the stage of treatment. But, there are few papers that study an activating effect of inorganic reactants upon natural coals structure and their behaviour at pyrolysis. One of the methods which allows to judge structural transformation in coals at their impregnation by inorganic substances is an X-ray analysis. (orig.)

  2. Comparison of Surface and Structural Properties of Carbonaceous Materials Prepared by Chemical Activation of Tomato Paste Waste: The Effects of Activator Type and Impregnation Ratio

    Directory of Open Access Journals (Sweden)

    Nurgul Ozbay


    Full Text Available Activated carbons were prepared by carbonization of tomato paste processing industry waste at 500°C followed by chemical activation with KOH, K2CO3, and HCl in N2 atmosphere at low temperature (500°C. The effects of different activating agents and impregnation ratios (25, 50, and 100 wt.% on the materials’ characteristics were examined. Precursor, carbonized tomato waste (CTW, and activated carbons were characterized by using ultimate and proximate analysis, thermogravimetric analysis (TG/DTG, Fourier transform-infrared (FT-IR spectroscopy, X-ray fluorescence (XRF spectroscopy, point of zero charge measurements (pHPZC, particle size analyzer, scanning electron microscopy (SEM, energy dispersive X-ray (EDX spectroscopy, nitrogen adsorption/desorption isotherms, and X-ray diffraction (XRD analysis. Activation process improved pore formation and changed activated carbons’ surface characteristics. Activated carbon with the highest surface area (283 m3/g was prepared by using 50 wt.% KOH as an activator. According to the experimental results, tomato paste waste could be used as an alternative precursor to produce low-cost activated carbon.

  3. Investigation of the metabolic consequences of impregnating spinach leaves with trehalose and applying a pulsed electric field

    NARCIS (Netherlands)

    Dymek, Katarzyna; Panarese, Valentina; Herremans, Els; Cantre, Dennis; Schoo, Rick; Torano, Javier Sastre|info:eu-repo/dai/nl/304840424; Schlupmann, Henriette|info:eu-repo/dai/nl/304827819; Wadso, Lars; Verboven, Pieter; Nicolai, Bart M.; Dejmek, Petr; Galindo, Federico Gomez


    The impregnation of leafy vegetables with cryoprotectants using a combination of vacuum impregnation (VI) and pulsed electric fields (PEF) has been proposed by our research group as a method of improving their freezing tolerance and consequently their general quality after thawing. In this study, we

  4. Nanoscale zero-valent iron impregnation of covalent organic polymer grafted activated carbon for water treatment

    DEFF Research Database (Denmark)

    Mines, Paul D.; Uthuppu, Basil; Thirion, Damien


    , the effectiveness of nZVI has its limitations, due to its high reactivity and subsequent loss of degradative ability. Therefore, nZVI must be stabilized in a matrix allowing for the maintaining of reactivity, as well as the protection from the effects of the surrounding environment. By employing a nanoporous...

  5. Ecological risks of an old wood impregnation mill: application of the triad approach.

    NARCIS (Netherlands)

    Karjalainen, A.-M.; Kilpi-Koski, J.; Väisänen, A.O.; Penttinen, S.; van Gestel, C.A.M.; Penttinen, O.-P.


    Although many studies deal with the distribution and mobility of chromated copper arsenate (CCA) metals in soil, the ecotoxicity of CCA-contaminated soils is rarely studied. The Triad approach was applied to determine the ecological risks posed by a CCA mixture at a decommissioned wood impregnation

  6. Computational analysis of the interaction between impregnation, forming and curing in pultrusion

    NARCIS (Netherlands)

    Carlone, Pierpaolo; Baran, Ismet; Akkerman, Remko; Palazzo, Gaetano S.


    Numerical and analytical models dealing with different physics involved in pultrusion are combined in the optic of an integrated analysis of the process. The impregnation stage is simulated by means of a CFD multiphase model, evaluating the pressure and velocity field in the liquid resin. Composite


    Directory of Open Access Journals (Sweden)

    G.V. Bezprozvannych


    Full Text Available Correlation between parameters characterizing mechanical and thermal ageing of paper-impregnated insulation of medium voltage power cables is revealed. On the basis of linear and exponential regression analysis at confidence coefficient of 0.95, critical values of dielectric loss tangent of wrapping and phase insulation corresponding to the cable life termination are found.

  8. Impacts of impregnation with boric acid and borax on the red colour ...

    African Journals Online (AJOL)

    This study was performed to determine the impacts of impregnation with boric acid and borax on the red colour tone of some hardwoods and varnishes. For this purpose, the test specimens prepared from Oriental beech ( Fagus orientalis Lipsky) and European oak (Quercus petraea Liebl.) wood which met the requirements ...

  9. Impregnated membranes for direct methanol fuel cells at high methanol concentrations

    NARCIS (Netherlands)

    Yildirim, M.H.; Schwarz, Alexander; Stamatialis, Dimitrios; Wessling, Matthias


    Sulfonated poly(phthalazinone ether ketone) (SPPEK) impregnated Solupor® microporous film (SPPEK–PE) and pure SPPEK membranes with two different ion-exchange capacities (IECs) were prepared and characterized for use in DMFC applications. Swelling, proton conductivity, diffusion and DMFC experiments

  10. Impacts of impregnation with boric acid and borax on the red colour ...

    African Journals Online (AJOL)



    Aug 18, 2009 ... After impregnation, surfaces were coated by cellulosic, synthetic, polyurethane ... coated only with paint and varnish have surface protec- tion only for two .... Control (Co). Boric acid (Ba). Borax (Bx). 14.46 A. 12.05 C. 13.38 B. Varnishes***. Colour (red)a. Cellulosic (Cv). Synthetic (Sn). Polyurethane (Pu).

  11. Bacterial Adhesion Forces to Ag-Impregnated Contact Lens Cases and Transmission to Contact Lenses

    NARCIS (Netherlands)

    Qu, Wenwen; Busscher, Henk J.; van der Mei, Henny C.; Hooymans, Johanna M. M.

    Purpose: To measure adhesion forces of Pseudomonas aeruginosa, Staphylococcus aureus, and Serratia marcescens to a rigid contact lens (CL), standard polypropylene, and Ag-impregnated lens cases using atomic force microscopy and determine bacterial transmission from lens case to CL. Methods: Adhesion

  12. The Effects of Natural Weathering on Color Stability of Impregnated and Varnished Wood Materials

    Directory of Open Access Journals (Sweden)

    Turkay Turkoglu


    Full Text Available The aim of this study was to investigate effects of natural weathering on color stability of Scots pine (Pinus sylvestris L. and Oriental beech (Fagus orientalis L. impregnated with some chemicals [tanalith-E (TN-E, adolit-KD5 (AD-KD5, and chromated copper arsenate (CCA] and then varnished [synthetic varnish (SV and polyurethane varnish (PV]. While applying varnish increased lightness, impregnation decreased lightness of the wood specimens before natural weathering. Natural weathering caused greenish, bluish, and dark color tones of the wood surface. Total color change was increased with increasing exposure times in natural weathering. Untreated (control wood specimens exhibited higher color changes than the other wood specimens in all the stages of natural weathering. The total color changes of untreated Oriental beech specimens were less than untreated Scots pine specimens. The color stability of impregnated and varnished wood specimens gave better results than untreated and solely varnished wood specimens after natural weathering. The best color stability was obtained from both Oriental beech and Scots pine wood impregnated with TN-E before PV coating.

  13. Electrochemical in-situ impregnation of wood using a copper nail as source for copper

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Block, Thomas; Nymark, Morten


    A new method for copper impregnation of wood in structures was suggested and tested in laboratory scale with specimen of new pine sapwood. A copper nail and a steel screw were placed in the wood, and an electric direct current field was applied, so the copper nail was anode and the screw...

  14. Removal of lanthanum and gadolinium from nitrate medium using Aliquat-336 impregnated onto Amberlite XAD-4. (United States)

    El-Sofany, E A


    Aliquat-336 in benzene was supported on Amberlite XAD-4 crosslinked polystyrene resin. The use of XAD-4 impregnated with Aliquat-336 resin for removal of lanthanum(III) and gadolinium(III) from nitrate medium was carried out using batch technique. Various parameters affecting the uptake of these metal ions such as contact time, metal ion concentrations, V/m and pH value were separately studied. Effect of temperature on the equilibrium distribution values has been studied to evaluate the changes in standard thermodynamic quantities. A comparison of kinetic models applied to the adsorption rate data was evaluated for Lagergren first order, the pseudo second order and Morris-Weber kinetic models. From the results, both pseudo second order and intraparticle diffusion models were found to best correlate the experimental rate data. The capacity of the impregnated resin for both lanthanum(III) and gadolinium(III) was found to be 4.73 and 4.44 mg/g. From the results, impregnation of Aliquat-336 onto Amberlite XAD-4 provides an efficient impregnated resin for the removal of lanthanum(III) and gadolinium(III) from 0.1M nitrate aqueous solution.

  15. Techno-economic evaluation of solvent impregnated particles in a bioreactor

    NARCIS (Netherlands)

    Berg, C. van den; Boon, F.; Roelands, C.P.M.; Bussmann, P.J.Th.; Goetheer, E.L.V.; Verdoes, D.; Wielen, L.A.M.


    Most fermentation products have a feedback inhibiting effect on the host organism. In situ product recovery (ISPR) can be a means to overcome this product inhibition in fermentations. Particles such as solvent impregnated resins or capsules can be valuable tools for product recovery based on

  16. Iron oxide impregnated filter paper (Pi test): a review of its development and methodological research

    NARCIS (Netherlands)

    Chardon, W.J.; Menon, R.G.; Chien, S.H.


    Iron oxide impregnated filter paper (FeO paper) has been used to study the availability of phosphorus (P) to plants and algae, P desorption kinetics and P dynamics in the field. Since its initial development a number of differences in the method of preparation of the paper and its application have

  17. Phosphate adsorption on aluminum-impregnated mesoporous silicates : surface structure and behavior of adsorbents (United States)

    Eun Woo Shin; James S. Han; Min Jang; Soo-Hong Min; Jae Kwang Park; Roger M. Rowell


    Phosphorus from excess fertilizers and detergents ends up washing into lakes, creeks, and rivers. This overabundance of phosphorus causes excessive aquatic plant and algae growth and depletes the dissolved oxygen supply in the water. In this study, aluminum-impregnated mesoporous adsorbents were tested for their ability to remove phosphate from water. The surface...

  18. Weed Control and Seedling Performance Using Oust, Velpar, and Velpar+Oust Impregnated Diammonium Phosphate (United States)

    J.L. Yeiser


    Technology that combines herbicide and fertilizer into one treatment thereby reducing application costs while enhancing growth is needed. Four clean and well-prepared sites in TX, MS, and AL were tested. Study objectives were to evaluate the effectiveness of diammonium phosphate (DAP) impregnated with Oust, Velpar, or Velpar+Oust for herbaceous weed control and newly...

  19. Catalytic flash pyrolysis of oil-impregnated-wood and jatropha cake using sodium based catalysts

    NARCIS (Netherlands)

    Ali Imran, A.; Bramer, Eduard A.; Seshan, Kulathuiyer; Brem, Gerrit


    Catalytic pyrolysis of wood with impregnated vegetable oil was investigated and compared with catalytic pyrolysis of jatropha cake making use of sodium based catalysts to produce a high quality bio-oil. The catalytic pyrolysis was carried out in two modes: in-situ catalytic pyrolysis and post

  20. Sorption kinetics for the removal of aldehydes from aqueous streams with extractant impregnated resins

    NARCIS (Netherlands)

    Babic, K.; van der Ham, Aloysius G.J.; de Haan, A.B.


    The sorption kinetics for the removal aldehydes from aqueous solutions with Amberlite XAD-16 and MPP particles impregnated with Primene JM-T was investigated. A model, accounting for the simultaneous mass transfer and chemical reaction, is developed to describe the process. It is based on the

  1. Efficacy of dental floss impregnated with chlorhexidine on reduction of supragingival biofilm: a randomized controlled trial. (United States)

    Muniz, F W M G; Sena, K S; de Oliveira, C C; Veríssimo, D M; Carvalho, R S; Martins, R S


    The use of a toothbrush has a limited ability to control the dental biofilm in interproximal areas. Therefore, specialized devices, such as dental floss, may be useful for these specific areas. This study aimed to investigate the efficacy of dental floss impregnated with 5% chlorhexidine gluconate on the reduction of the supragingival biofilm. This research was parallel, single-blind, controlled and randomized, and contained a sample of thirty dental students from the Faculty of Pharmacy, Dentistry and Nursing of the Federal University of Ceará, Brazil, who were divided equally into three groups. The negative control group (NC) did not utilize any kind of interproximal cleaning; the positive control group (PC) used waxed floss without impregnation twice a day; and the test group (T) used the same dental floss, which was impregnated with 5% chlorhexidine gluconate, twice a day. For all groups, this study lasted for 15 days. The presence of a biofilm was evaluated on four surfaces (mesiobuccal, distobuccal, mesiolingual and distolingual) by the Quigley-Hein Index, resulting in four scores for each tooth. Group T had the lowest plaque scores, showing a significant difference compared to group NC (P dental floss impregnated with 5% chlorhexidine gluconate resulted in additional reductions in the supragingival biofilm relative to the results achieved with conventional waxed floss on the anterior teeth of a well-motivated and well-instructed population. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Study on Leaching of Copper Nanoparticles in Combined Impregnation- Densification Treatments of wood after Accelerated Aging

    Directory of Open Access Journals (Sweden)

    Aisona Talaei


    Full Text Available This study was performed to evaluate the leaching rate of copper nanoparticles in combined impregnation-densification treated poplar and spruce wood after accelerated aging. Specimens were prepared by impregnation with 200 and 400 ppm nano-copper suspensions, followed by pre-steam treatment and densification. Impregnation was done in a sealed vessel with 4 bar pressure in 20 minutes. Half of the specimens were oven-dried and steamed at 150°C for 2 hours and immediately densified under the hot press at 170°C for 3 hours to reach to the 33% compression rate. All specimens were exposed to the 6 steps accelerated aging procedure according to ASTM D-1037. Leaching test was performed according to EN84 standard (1997 for a period of 14 days. The leached residues were investigated in the Mineral Exploration and Geological Center by atomic absorption method. Results showed that nano-copper particles in impregnated specimens had no leaching; but the pre-steaming and densification treatments led to leaching the nano-copper particles from the treated wood.

  3. Fast, versatile x-ray fluorescence method for measuring tin in impregnated wood

    DEFF Research Database (Denmark)

    Drabæk, I.; Christensen, Leif Højslet


    The present paper describes an energy-dispersive x-ray fluorescence method for measuring tin in bis(tri-n-butyl)tin-oxide impregnated wood. The proposed method is of the backscatter/fundamental parameter type. Its versatility, precision, and accuracy is demonstrated by analyses of eleven samples...


    Directory of Open Access Journals (Sweden)

    Nurwati Hadjib


    Full Text Available The disadvantage of  fast-growing species is  that they have inferior physical and mechanical properties. Polystyrene impregnation can be applied to improve physical and mechanical properties. Wood samples, which were dried  until 10% moisture content were put into impregnating tank and vacuum pressured  at 20-mm Hg  for  two hours. During  the gradual release of  vacuum, styrene monomers,  vinyl acetate  monomers  and  terburyl-peroxide catalyst was streamed  into  the tank. Afterwards, the pressure inside the tank was allowed to decrease to 500 mm Hg and kept for 60 minutes. Wood samples which had been impregnated were subsequently immersed in water, then wrapped in aluminum foils and put in the oven for 24 hours at 60°C. The samples were then tested for the polymer loading and their physical and mechanical properties. The results showed that the polymer loadings in wood plastics with the species  of origin (i.e. consecutively sengon, pine and rubber wood were 118%, 72% and 44%, respectively. Impregnation with polystyrene  (copolymer of styrene and vinyl acetate monomers could improve the physical and mechanical properties of wood plastics, i.e.  specific gravity, moisture content, water absorption,  shrinkage/ swelling, compression parallelto the wood grain, MOR and MOE. Greater  use of vinyl acetate decreased physical and mechanical properties.

  5. Infrared Spectroscopic Study on the Modified Mechanism of Aluminum-Impregnated Bone Charcoal

    Directory of Open Access Journals (Sweden)

    Hao Li


    Full Text Available Fluoride contamination in drinking water is a prominent and widespread problem in many parts of the world. Excessive ingestion of fluoride through water can lead to the high risk of fluorosis in human body. Bone charcoal, with the principal active component of hydroxyapatite, is a frequently used adsorbent for fluoride removal. Many laboratory experiments suggest that the aluminum-impregnated bone charcoal is an effective adsorbent in defluoridation. However, the mechanisms underlying this modification process are still not well understood, which in turn greatly impedes the further studies on other different modified adsorbents. To address this issue, we used the infrared spectroscopy to examine the bone charcoal and the aluminum-impregnated bone charcoal, respectively. The comparative results show that the −OH peak of infrared spectroscopy has been intensified after modification. This significant change helped speculate the modified mechanism of the aluminum-impregnated bone charcoal. In addition, it is found that the hydroxide ion dissociates from hydroxyapatite in the modification process. Such finding implies that the tetrahydroxoaluminate can be combined with the hydroxyapatite and the aluminum ion can be impregnated onto the bone char surface.

  6. Impacts of impregnation with boric acid and borax on the red colour ...

    African Journals Online (AJOL)



    Aug 18, 2009 ... polyurethane varnish. Consequently, impregnation of wood material with boron compounds show decreasing impact on the red colour tone. This impact might be taken into consideration in the applications where red color tone values of hardwood are important. Key words: Red colour tone, boric acid, ...

  7. An in vitro Method for Predicting Inhalation Toxicity of Impregnation Spray Products

    DEFF Research Database (Denmark)

    Sørli, Jorid B.; Hansen, Jitka S.; Nørgaard, Asger Wisti


    Impregnation spray products are used for making surfaces water and dirt repellent. The products are composed of one or more active film-forming components dissolved or suspended in an appropriate solvent mixture. Exposure to impregnation spray products may cause respiratory distress and new cases...... of the inhalation toxicity of impregnation spray products and thus may reduce the need for animal testing....... of this study was to evaluate whether disruption of the pulmonary surfactant film can be used as a predictor of the toxic effects in vivo. Nine impregnation products with various chemical compositions were selected for testing and the main constituents of each product, e.g., solvents, co-solvents and film...... and in vivo. The true positive rate of the in vitro method was 100%, i.e. the test could correctly identify all products with toxic effects in vivo, the true negative rate was 40%. Investigation of inhibition of the pulmonary surfactant system, e.g. by capillary surfactometry, was found useful for evaluation...

  8. Anti-biofilm and cytotoxicity activity of impregnated dressings with silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Velázquez-Velázquez, Jorge Luis [Laboratorio de Microbiología, Facultad de Ciencias Químicas, UASLP (Mexico); Santos-Flores, Andrés; Araujo-Meléndez, Javier [Servicio de Epidemiología del Hospital Central “Dr. Ignacio Morones Prieto”, San Luis Potosí (Mexico); Sánchez-Sánchez, Roberto; Velasquillo, Cristina [Laboratorio de Biotecnología, Instituto Nacional de Rehabilitación (Mexico); González, Carmen [Laboratorio de Fisiología Celular, Facultad de Ciencias Químicas, UASLP (Mexico); Martínez-Castañon, Gabriel [Maestría en Ciencias Odontológicas Facultad de Estomatología, UASLP (Mexico); Martinez-Gutierrez, Fidel, E-mail: [Laboratorio de Microbiología, Facultad de Ciencias Químicas, UASLP (Mexico)


    Infections arising from bacterial adhesion and colonization on chronic wounds are a significant healthcare problem. Silver nanoparticles (AgNPs) impregnated in dressing have attracted a great deal of attention as a potential solution. The goal of the present study was to evaluate the anti-biofilm activities of AgNPs impregnated in commercial dressings against Pseudomonas aeruginosa, bacteria isolated of chronic wounds from a hospital patient. The antimicrobial activity of AgNPs was tested within biofilms generated under slow fluid shear conditions using a standard bioreactor. A 2-log reduction in the number of colony-forming units of P. aeruginosa was recorded in the reactor on exposure to dressing impregnated with 250 ppm of AgNPs, diameter 9.3 ± 1.1 nm, and also showed compatibility to mammalian cells (human fibroblasts). Our study suggests that the use of dressings with AgNPs may either prevent or reduce microbial growth in the wound environment, and reducing wound bioburden may improve wound-healing outcomes. - Highlights: • Biological activities of silver nanoparticles for wound-healing purposes • Characterization of the silver nanoparticles impregnated in dressings • Reduction in the P. aeruginosa biofilm formation was statistically significant. • Compatibility to human dermal fibroblasts as the main cell type involved in the reparation • AgNPs covering the surfaces would provide great potential for prevention and treatment.

  9. Gentamycin-impregnated calcium phosphate cement for calcaneal osteomyelitis: a case report. (United States)

    Iwakura, Takashi; Lee, Sang Yang; Niikura, Takahiro; Miwa, Masahiko; Sakai, Yoshitada; Nishida, Kotaro; Kuroda, Ryosuke; Kurosaka, Masahiro


    We report a case of chronic calcaneal osteomyelitis in a diabetic patient who was successfully treated with radical debridement and gentamycin-impregnated calcium phosphate cement. At 1.5-year follow-up, the patient could walk without any assistance. Calcium phosphate cement is an effective local antibiotic delivery system and a biocompatible material for filling the debrided space to facilitate bone formation.

  10. Molecular Dimensions and Surface Diffusion Assisted Mechanically Robust Slippery Perfluoropolyether Impregnated Mesoporous Alumina Interfaces. (United States)

    Rowthu, Sriharitha; Balic, Edin E; Hoffmann, Patrik


    Accomplishing mechanically robust omniphobic surfaces is a long-existing challenge, and can potentially find applications in bioengineering, tribology and paint industries. Slippery liquid impregnated mesoporous α-Al2O3 interfaces are achieved with water, alkanes, water based and oil based high viscosity acrylic paints. Incredibly high abrasion-resistance (wear coefficients ≤ 10-8 mm3.N-1.m-1) and ultra-low friction coefficients (≤ 0.025) are attained, attributing to the hard alumina matrix and continuous replenishment of perfluoropolyether aided by capillarity and surface diffusion processes. A variety of impregnating liquids employed suggest that large molecules, faster surface diffusion and lowest evaporation rate generate the rare combination of high wear-resistance and omniphobicity. It is noteworthy that these novel interfaces exhibit outstanding load bearing capacity up to 350 MPa; 3 orders of magnitude higher than achievable by the state of the art omniphobic surfaces. Further, our developed thermodynamic calculations suggest that the relative thermodynamic stability of liquid impregnated composites is linearly proportional to the spreading coefficient (S) of the impregnating liquid with the matrix material and is an important tool for the selection of an appropriate matrix material. © 2017 IOP Publishing Ltd.

  11. Two-dimensional bismuth oxybromide coupled with molybdenum disulphide for enhanced dye degradation using low power energy-saving light bulb. (United States)

    Lee, W P Cathie; Wong, Fhu-Hin; Attenborough, Nicole K; Kong, Xin Ying; Tan, Lling-Lling; Sumathi, S; Chai, Siang-Piao


    In the present work, two-dimensional bismuth oxybromide (BiOBr) was synthesized and coupled with co-catalyst molybdenum disulphide (MoS 2 ) via a simple hydrothermal process. The photoactivity of the resulting hybrid photocatalyst (MoS 2 /BiOBr) was evaluated under the irradiation of 15 W energy-saving light bulb at ambient condition using Reactive Black 5 (RB5) as model dye solution. The photo-degradation of RB5 by BiOBr loaded with 0.2 wt% MoS 2 (MoBi-2) exhibited more than 1.4 and 5.0 folds of enhancement over pristine BiOBr and titanium dioxide (Degussa, P25), respectively. The increased photocatalytic performance was a result of an efficient migration of excited electrons from BiOBr to MoS 2 , prolonging the electron-hole pairs recombination rate. A possible charge transfer diagram of this hybrid composite photocatalyst, and the reaction mechanism for the photodegradation of RB5 were proposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Large Scale Solid Phase Synthesis of Peptide Drugs: Use of Commercial Anion Exchange Resin as Quenching Agent for Removal of Iodine during Disulphide Bond Formation

    Directory of Open Access Journals (Sweden)

    K. M. Bhaskara Reddy


    Full Text Available The S-acetamidomethyl (Acm or trityl (Trt protecting groups are widely used in the chemical synthesis of peptides that contain one or more disulfide bonds. Treatment of peptides containing S-Acm protecting group with iodine results in simultaneous removal of the sulfhydryl protecting group and disulfide formation. However, the excess iodine needs to be quenched or adsorbed as quickly as possible after completion of the disulfide bond formation in order to minimize side reactions that are often associated with the iodination step. We report here a simple method for simultaneous quenching and removal of iodine and isolation of disulphide bridge peptides. The use of excess inexpensive anion exchange resin to the oxidized peptide from the aqueous acetic acid/methanol solution affords quantitative removal of iodine and other color impurities. This improves the resin life time of expensive chromatography media that is used in preparative HPLC column during the purification of peptide using preparative HPLC. Further, it is very useful for the conversion of TFA salt to acetate in situ. It was successfully applied commercially, to the large scale synthesis of various peptides including Desmopressin, Oxytocin, and Octreotide. This new approach offers significant advantages such as more simple utility, minimal side reactions, large scale synthesis of peptide drugs, and greater cost effectiveness.

  13. Large Scale Solid Phase Synthesis of Peptide Drugs: Use of Commercial Anion Exchange Resin as Quenching Agent for Removal of Iodine during Disulphide Bond Formation. (United States)

    Reddy, K M Bhaskara; Kumari, Y Bharathi; Mallikharjunasarma, Dokka; Bulliraju, Kamana; Sreelatha, Vanjivaka; Ananda, Kuppanna


    The S-acetamidomethyl (Acm) or trityl (Trt) protecting groups are widely used in the chemical synthesis of peptides that contain one or more disulfide bonds. Treatment of peptides containing S-Acm protecting group with iodine results in simultaneous removal of the sulfhydryl protecting group and disulfide formation. However, the excess iodine needs to be quenched or adsorbed as quickly as possible after completion of the disulfide bond formation in order to minimize side reactions that are often associated with the iodination step. We report here a simple method for simultaneous quenching and removal of iodine and isolation of disulphide bridge peptides. The use of excess inexpensive anion exchange resin to the oxidized peptide from the aqueous acetic acid/methanol solution affords quantitative removal of iodine and other color impurities. This improves the resin life time of expensive chromatography media that is used in preparative HPLC column during the purification of peptide using preparative HPLC. Further, it is very useful for the conversion of TFA salt to acetate in situ. It was successfully applied commercially, to the large scale synthesis of various peptides including Desmopressin, Oxytocin, and Octreotide. This new approach offers significant advantages such as more simple utility, minimal side reactions, large scale synthesis of peptide drugs, and greater cost effectiveness.

  14. Impregnated central venous catheters for prevention of bloodstream infection in children (the CATCH trial): a randomised controlled trial. (United States)

    Gilbert, Ruth E; Mok, Quen; Dwan, Kerry; Harron, Katie; Moitt, Tracy; Millar, Mike; Ramnarayan, Padmanabhan; Tibby, Shane M; Hughes, Dyfrig; Gamble, Carrol


    Impregnated central venous catheters are recommended for adults to reduce bloodstream infections but not for children because there is not enough evidence to prove they are effective. We aimed to assess the effectiveness of any type of impregnation (antibiotic or heparin) compared with standard central venous catheters to prevent bloodstream infections in children needing intensive care. We did a randomised controlled trial of children admitted to 14 English paediatric intensive care units. Children younger than 16 years were eligible if they were admitted or being prepared for admission to a participating paediatric intensive care unit and were expected to need a central venous catheter for 3 or more days. Children were randomly assigned (1:1:1) to receive a central venous catheter impregnated with antibiotics, a central venous catheter impregnated with heparin, or a standard central venous catheter with computer generated randomisation in blocks of three and six, stratified by method of consent, site, and envelope storage location within the site. The clinician responsible for inserting the central venous catheter was not masked to allocation, but allocation was concealed from patients, their parents, and the paediatric intensive care unit personnel responsible for their care. The primary outcome was time to first bloodstream infection between 48 h after randomisation and 48 h after central venous catheter removal with impregnated (antibiotic or heparin) versus standard central venous catheters, assessed in the intention-to-treat population. Safety analyses compared central venous catheter-related adverse events in the subset of children for whom central venous catheter insertion was attempted (per-protocol population). This trial is registered with ISRCTN number, ISRCTN34884569. Between Nov 25, 2010, and Nov 30, 2012, 1485 children were recruited to this study. We randomly assigned 502 children to receive standard central venous catheters, 486 to receive

  15. Visualising impregnated chitosan in Pinus radiata early wood cells using light and scanning electron microscopy. (United States)

    Singh, Adya P; Singh, Tripti; Rickard, Catherine L


    Chitosan, a deacetylated product of an abundant naturally occurring biopolymer chitin, has been used in a range of applications, particularly in food and health areas, as an antimicrobial agent. In the work reported here Pinus radiata wood was impregnated with chitosan as an environmentally compatible organic biocide (Eikenes et al., 2005a,b) to protect wood against wood deteriorating microorganisms and to thus prolong the service life of wooden products. We developed sample preparation techniques targeted to visualise impregnated chitosan within wood tissues using light microscope and field-emission scanning electron microscope (FE-SEM). Sections were viewed with the light microscope without staining with a dye as well as after staining with the dye toluidine blue. Light microscopy was also undertaken on sections that had been stained with 1% aqueous osmium tetroxide (OsO(4)). For SEM observations, the sections were treated with OsO(4) and then examined with the FE-SEM, first in the secondary electron imaging mode (SEI) and then in the backscattered electron imaging (BEI) mode, imaging the same areas of a section in both SEI and BEI modes. The preparation techniques employed and the combined use of light and scanning electron microscopy provided valuable complementary information, revealing that chitosan had penetrated into the cavities (cell lumens, intercellular spaces) of all sizes present within wood tissues and had also impregnated early wood cell walls. The information obtained is discussed in relation to its importance in further development of chitosan formulations and refinement of impregnation technologies to optimise chitosan impregnation into and distribution within wood tissues as well as in assessing chitosan efficacy. Copyright 2009 Elsevier Ltd. All rights reserved.

  16. Clinical evaluation of a silver impregnated foam dressing in paediatric partial-thickness burns. (United States)

    Glat, P M; Zhang, S H; Burkey, B A; Davis, W J


    MepilexAg, a silver-impregnated foam dressing, was introduced to our institution in 2007 and our outcomes in the treatment of paediatric burns were observed to improve significantly. In order to confirm these observations, we wanted to evaluate the results of using the silver-impregnated foam dressing in partial-thickness paediatric burns.Method: In this retrospective, study, the St. Christopher's Hospital burn registry was used to identify subjects, who were otherwise in excellent health at baseline, over an 18-month period,. Outcomes included length of stay, intravenous narcotic use, and time to healing. No direct comparative studies were performed. This was followed by a non-comparative prospective study involving 22 paediatric patients, aged 1-4 years, with partial-thickness burns. This was a sub-study of a larger randomized controlled trial involving adults with partial-thickness burns, comparing the silver-impregnated foam dressing with Silvadene. In the retrospective part of the study, the silver-impregnated foam dressing was used successfully for the treatment of partial-thickness paediatric burns, with few complications and infections, allowing a shorter hospital stay, fewer dressings, and less pain medication than for historical controls. In the non-comparative prospective study, of 22 paediatric patients 50% healed completely within I week of treatment. The mean length of stay was 3.77 days and the mean number of dressings used was 1.64.Aithough narcotic usage was not assessed, patient surveys showed stinging or burning to be recorded as 'never' in 13 patients, 'rarely' in 8 patients, and 'sometimes' in I patient. The silver-impregnated foam dressing is effective and safe for use in partial-thickness paediatric burns, eliminating the need for daily dressings.


    Safdar, Nasia; O’Horo, John C.; Ghufran, Aiman; Bearden, Allison; Didier, Maria Eugenia; Chateau, Dan; Maki, Dennis G.


    Background Catheter related bloodstream infections (CRBSI) are associated with significant morbidity and mortality and effective methods for their prevention are needed. Objective To assess the efficacy of a chlorhexidine-impregnated dressing for prevention of central venous catheter-related colonization and CRBSI using meta-analysis. Data Sources Multiple computerized database searches supplemented by manual searches including relevant conference proceedings. Study Selection Randomized controlled trials (RCT) evaluating the efficacy of a chlorhexidine-impregnated dressing compared with conventional dressings for prevention of catheter colonization and CRBSI. Data Extraction Data were extracted on patient and catheter characteristics and outcomes. Data Synthesis Pooled estimates of the relative risk (RR) and 95% confidence intervals (CI) were obtained using the DerSimonian and Laird random effects model and the Mantel-Haenszel fixed effects model. Heterogeneity was assessed using the Cochran Q statistic and I2. Subgroup analyses were used to explore heterogeneity. Results Nine RCTs met the inclusion criteria. Use of a chlorhexidine-impregnated dressing resulted in a reduced incidence of CRBSI (random effects RR 0.57, 95% CI 0.42–0.79, P=0.002). The incidence of catheter colonization was also markedly reduced in the chlorhexidine-impregnated dressing group (random effects RR 0.51, 95% CI 0.39–0.67, Pchlorhexidine-impregnated dressing is beneficial in preventing catheter colonization and, more importantly, CRBSI and warrants routine use in patients at high risk of CRBSI and CVC or arterial catheter colonization in ICUs. PMID:24674924

  18. Carbon Cryogel Silicon Composite Anode Materials for Lithium Ion Batteries (United States)

    Woodworth James; Baldwin, Richard; Bennett, William


    A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 10 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-4,9 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

  19. Synthesis of polysiloxane with quaternized N-halamine moieties for antibacterial coating of polypropylene via supercritical impregnation technique (United States)

    Chen, Yong; Yu, Panwei; Feng, Chunyan; Wang, Yuyu; Han, Qiuxia; Zhang, Qiang


    Development of polymers with enhanced biocidal ability to coated surfaces by a simple and versatile approach is very desirable in biomaterial area. A polysiloxane containing both quaternary ammonium and N-halamine was synthesized by silane alcoholysis between poly(methylhydrosiloxane) (PMHS) and 3-bromo-1-propanol, subsequent quaternization with 3-(3-(dimethylamino)propyl)-5,5-dimethylhydantoin (DMAPDMH), and chlorination with tert-butyl hypochlorite. The quaternized N-halamine polysiloxane was impregnated into polypropylene (PP) in supercritical carbon dioxide (scCO2) and formed an antibacterial coating layer of 61 nm. The synthetic procedures and coating results were characterized using FTIR, NMR, XPS, and SEM. The polysiloxane layer showed enhanced synergetic antibacterial ability, providing a total kill of a 7-log S. aureus and E. coli within 10 min of contact. The rechargability and stability of the coating layer toward washing cycles, storage, and UV irradiation were good. This coating procedure uses environmentally benign CO2 as solvent and affords a general method to functionalize inert polymers with biocidal capability.

  20. Process for preparing tapes from thermoplastic polymers and carbon fibers (United States)

    Chung, Tai-Shung (Inventor); Furst, Howard (Inventor); Gurion, Zev (Inventor); McMahon, Paul E. (Inventor); Orwoll, Richard D. (Inventor); Palangio, Daniel (Inventor)


    The instant invention involves a process for use in preparing tapes or rovings, which are formed from a thermoplastic material used to impregnate longitudinally extended bundles of carbon fibers. The process involves the steps of (a) gas spreading a tow of carbon fibers; (b) feeding the spread tow into a crosshead die; (c) impregnating the tow in the die with a thermoplastic polymer; (d) withdrawing the impregnated tow from the die; and (e) gas cooling the impregnated tow with a jet of air. The crosshead die useful in the instant invention includes a horizontally extended, carbon fiber bundle inlet channel, means for providing melted polymer under pressure to the die, means for dividing the polymeric material flowing into the die into an upper flow channel and a lower flow channel disposed above and below the moving carbon fiber bundle, means for applying the thermoplastic material from both the upper and lower channels to the fiber bundle, and means for withdrawing the resulting tape from the die.

  1. Synthesis of carbon-encapsulated metal nanoparticles from wood char (United States)

    Yicheng Du; Chuji Wang; Hossein Toghiani; Zhiyong Cai; Xiaojian Liu; Jilei Zhang; Qiangu Yan


    Carbon-encapsulated metal nanoparticles were synthesized by thermal treatment of wood char, with or without transition metal ions pre-impregnated, at 900ºC to 1,100ºC. Nanoparticles with concentric multilayer shells were observed. The nanoparticles were analyzed by scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction...

  2. Effect of citrate ions on the softening of root crops prepared with freeze-thaw impregnation of macerating enzymes. (United States)

    Nakatsu, Sayaka; Shimoda, Mitsuya; Shibata, Kenya; Kajihara, Ryo; Ishihara, Masako; Sakamoto, Koji


    Freeze-thaw impregnation is a technique used for the rapid impregnation of substances into foodstuffs. Freeze-thaw impregnation with macerating enzymes has been applied to soften foodstuffs, while retaining their original shapes and flavors. In this study, we found that co-impregnation with citrate ions and macerating enzymes significantly facilitated the softening of root crops. When burdock roots were processed by the impregnating solution at pH 4.0-5.0, co-impregnated burdock roots exhibited 1/6-1/3 firmness values compared with burdock roots impregnated with only enzymes. The impregnation with citrate ions alone at pH 4.0 to 5.0 did not soften burdock roots. The firmness of burdock roots was positively correlated with the amount of water-insoluble calcium in the samples. The results suggested that the degradation of pectins by pectinolytic activities could promote contact with citrate to bridging-calcium ions interacting with the pectin chains. Therefore, the softening by the synergistic effect of citrate ions and macerating enzymes was related to the amount of pectins contained in root crops. That is, the synergistic effect was significant with burdock roots and carrots (from which 50% of polysaccharides are pectins) unlike with lotus rhizomes and bamboo shoots (from which 30% and 10% of polysaccharides are pectins, respectively). Freeze-thaw impregnation with macerating enzymes and citrate ions can be applied for the production of care foods which can be eaten without chewing. The softened products induce the pleasure of eating for consumers because their original shapes and flavors are retained. © 2014 Institute of Food Technologists®

  3. The effect of silanated and impregnated fiber on the tensile strength of E-glass fiber reinforced composite retainer

    Directory of Open Access Journals (Sweden)

    Niswati Fathmah Rosyida


    Full Text Available Background: Fiber reinforced composite (FRC is can be used in dentistry as an orthodontic retainer. FRC  still has a limitations because of to  a weak bonding between fibers and matrix. Purpose: This research was aimed to evaluate the effect of silane as coupling agent and fiber impregnation on the tensile strength of E-glass FRC. Methods: The samples of this research were classified into two groups each of which consisted of three subgroups, namely the impregnated fiber group (original, 1x addition of silane, 2x addition of silane and the non-impregnated fiber group (original, 1x addition of silane, 2x addition of silane. The tensile strength was measured by a universal testing machine. The averages of the tensile strength in all groups then were compared by using Kruskal Wallis and Mann Whitney post hoc tests. Results: The averages of the tensile strength (MPa in the impregnated fiber group can be known as follow; original impregnated fiber (26.60±0.51, 1x addition of silane (43.38±4.42, and 2x addition of silane (36.22±7.23. The averages of tensile strength (MPa in the non-impregnated fiber group can also be known as follow; original non-impregnated fiber (29.38±1.08, 1x addition of silane (29.38±1.08, 2x addition of silane (12.48±2.37. Kruskal Wallis test showed that there was a significant difference between the impregnated fiber group and the non-impregnated fiber group (p<0.05. Based on the results of post hoc test, it is also known that the addition of silane in the impregnated fiber group had a significant effect on the increasing of the tensile strength of E-glass FRC (p<0.05, while the addition of silane in the non-impregnated fiber group had a significant effect on the decreasing of the tensile strength of E-glass FRC. Conclusion: It can be concluded that the addition of silane in the non-silanated fiber group can increase the tensile strength of E-glass FRC, but the addition of silane in the silanated fiber group can

  4. Endocrine alterations around the time of abortion in mares impregnated with donkey or horse semen. (United States)

    Boeta, M; Zarco, L


    The objective of this study was to monitor and compare the concentrations of equine chorionic gonadotropin (eCG), progesterone and estrone sulphate during normal and failed pregnancies of mares impregnated with donkey or horse semen, relating their individual endocrine profiles to the time of pregnancy loss, and to the histopathologic findings in the aborted fetuses and placenta. Mares (n=54) were used, 32 of them impregnated with donkey semen and 22 impregnated with horse semen. Blood samples were taken twice a week from Day 35 to 120 of pregnancy. Ultrasonographic observations of the fetus were carried out twice a week. The incidence of abortion in mares impregnated with donkey semen (30%) was greater (P<0.05) than the 5% observed in mares impregnated with horse semen. From Week 8 to the end of the sampling period, the mean progesterone concentrations of mares with normal mule pregnancies were less (P<0.05) than those of mares with normal pregnancies with equine fetuses. The concentrations of eCG were less (P<0.05) in mule pregnancies from Week 6. Estrone sulphate concentrations were only different (P<0.05) between types of pregnancy on Weeks 13 and 14, being in this case greater with the mule pregnancies. Most of the abortions of mule fetuses were associated with lesser progesterone concentrations than the average for mares with successful mule pregnancies. Four of the abortions of mule fetuses and the only abortion of horse fetus occurred in mares with lesser progesterone and very low eCG concentrations, and were classified as caused by luteal impairment secondary to eCG deficiency; estrone sulphate concentrations were less than normal or absent before these abortions. Two mares aborted after several weeks of low progesterone concentrations in the presence of eCG concentrations that were normal for mule pregnancies, suggesting primary luteal deficiency. In three mares carrying a mule fetus, the concentrations of progesterone and estrone sulphate decreased

  5. Two-dimensional molybdenum disulphide nanosheet-covered metal nanoparticle array as a floating gate in multi-functional flash memories (United States)

    Han, Su-Ting; Zhou, Ye; Chen, Bo; Zhou, Li; Yan, Yan; Zhang, Hua; Roy, V. A. L.


    Semiconducting two-dimensional materials appear to be excellent candidates for non-volatile memory applications. However, the limited controllability of charge trapping behaviors and the lack of multi-bit storage studies in two-dimensional based memory devices require further improvement for realistic applications. Here, we report a flash memory consisting of metal NPs-molybdenum disulphide (MoS2) as a floating gate by introducing a metal nanoparticle (NP) (Ag, Au, Pt) monolayer underneath the MoS2 nanosheets. Controlled charge trapping and long data retention have been achieved in a metal (Ag, Au, Pt) NPs-MoS2 floating gate flash memory. This controlled charge trapping is hypothesized to be attributed to band bending and a built-in electric field ξbi between the interface of the metal NPs and MoS2. The metal NPs-MoS2 floating gate flash memories were further proven to be multi-bit memory storage devices possessing a 3-bit storage capability and a good retention capability up to 104 s. We anticipate that these findings would provide scientific insight for the development of novel memory devices utilizing an atomically thin two-dimensional lattice structure.Semiconducting two-dimensional materials appear to be excellent candidates for non-volatile memory applications. However, the limited controllability of charge trapping behaviors and the lack of multi-bit storage studies in two-dimensional based memory devices require further improvement for realistic applications. Here, we report a flash memory consisting of metal NPs-molybdenum disulphide (MoS2) as a floating gate by introducing a metal nanoparticle (NP) (Ag, Au, Pt) monolayer underneath the MoS2 nanosheets. Controlled charge trapping and long data retention have been achieved in a metal (Ag, Au, Pt) NPs-MoS2 floating gate flash memory. This controlled charge trapping is hypothesized to be attributed to band bending and a built-in electric field ξbi between the interface of the metal NPs and MoS2. The metal

  6. Expression of hypoallergenic Der f 2 derivatives with altered intramolecular disulphide bonds induces the formation of novel ER-derived protein bodies in transgenic rice seeds. (United States)

    Yang, Lijun; Hirose, Sakiko; Suzuki, Kazuya; Hiroi, Takachika; Takaiwa, Fumio


    House dust mites (HDM) are the most common source of indoor allergens and are associated with allergic diseases worldwide. To benefit allergic patients, safer and non-invasive mucosal routes of oral administration are considered to be the best alternative to conventional allergen-specific immunotherapy. In this study, transgenic rice was developed expressing derivatives of the major HDM allergen Der f 2 with reduced Der f 2-specific IgE reactivity by disrupting intramolecular disulphide bonds in Der f 2. These derivatives were produced specifically as secretory proteins in the endosperm tissue of seeds under the control of the endosperm-specific glutelin GluB-1 promoter. Notably, modified Der f 2 derivatives aggregated in the endoplasmic reticulum (ER) lumen and were deposited in a unique protein body (PB)-like structure tentatively called the Der f 2 body. Der f 2 bodies were characterized by their intracellular localization and physico-chemical properties, and were distinct from ER-derived PBs (PB-Is) and protein storage vacuoles (PB-IIs). Unlike ER-derived organelles such as PB-Is, Der f 2 bodies were rapidly digested in simulated gastric fluid in a manner similar to that of PB-IIs. Oral administration in mice of transgenic rice seeds containing Der f 2 derivatives encapsulated in Der f 2 bodies suppressed Der f 2-specific IgE and IgG production compared with that in mice fed non-transgenic rice seeds, and the effect was dependent on the type of Der f 2 derivative expressed. These results suggest that engineered hypoallergenic Der f 2 derivatives expressed in the rice seed endosperm could serve as a basis for the development of viable strategies for the oral delivery of vaccines against HDM allergy.

  7. Long-Lasting Permethrin-Impregnated Clothing Protects against Mosquito Bites in Outdoor Workers (United States)

    Londono-Renteria, Berlin; Patel, Jaymin C.; Vaughn, Meagan; Funkhauser, Sheana; Ponnusamy, Loganathan; Grippin, Crystal; Jameson, Sam B.; Apperson, Charles; Mores, Christopher N.; Wesson, Dawn M.; Colpitts, Tonya M.; Meshnick, Steven R.


    Outdoor exposure to mosquitoes is a risk factor for many diseases, including malaria and dengue. We have previously shown that long-lasting permethrin-impregnated clothing protects against tick and chigger bites in a double-blind randomized controlled trial in North Carolina outdoor workers. Here, we evaluated whether this clothing is protective against mosquito bites by measuring changes in antibody titers to mosquito salivary gland extracts. On average, there was a 10-fold increase in titer during the spring and summer when mosquito exposure was likely to be the highest. During the first year of the study, the increase in titer in subjects wearing treated uniforms was 2- to 2.5-fold lower than that of control subjects. This finding suggests that long-lasting permethrin-impregnated clothing provided protection against mosquito bites. PMID:26195460

  8. Waveguiding, absorption and emission properties of dye-impregnated oxidized porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Navarro-Urrios, D. [Nanoscience Laboratory, Department of Physics, University of Trento (Italy); Dpto. de Fisica Basica, University of La Laguna, Tenerife (Spain); Ghulinyan, M.; Riboli, F.; Pavesi, L. [Nanoscience Laboratory, Department of Physics, University of Trento (Italy); Capuj, N.E.; Oton, C.J. [Dpto. de Fisica Basica, University of La Laguna, Tenerife (Spain); Martin, I.R. [Dpto. de Fisica Fund. y Exp. Electr. y Sist., University of La Laguna, Tenerife (Spain)


    The waveguiding, absorption and emission properties of oxidised porous silicon waveguides when impregnated with Nile Blue have been studied. We present m-line measurements before and after the impregnation showing that the effective indices of the modes remain the same. When performing guided luminescence experiments, a structured emission band is measured. Using the refractive index profile extracted from m-line measurements it has been possible to simulate the emission lineshape assuming the observation of an interference pattern formed across the waveguide. We demonstrate that these oscillations appear because in the first hundreds of nanometers the dye concentration is several orders of magnitude higher than in the rest of the sample. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Fluorescence Sensing of Nitrite Ions on Polyvinylpyrrolidone/Zinc Oxide Composites Prepared by Impregnation Method (United States)

    Yuliati, L.; So'ad, S. Z. M.; Alim, N. S.; Lintang, H. O.


    A series of polyvinylpyrrolidone/zinc oxide (PVP/ZnO) composites with different loading amounts of PVP was prepared by an impregnation method. Successful formation of the composites was analyzed by the Fourier transform infrared (FTIR), diffuse reflectance ultraviolet-visible (DR UV-Vis) and fluorescence spectroscopies. Prepared composites were then further tested as fluorescence sensors by conducting quenching studies in the presence of nitrite ions (NO2 -). Among the prepared composites, the ZnO with 1% PVP exhibited the highest sensing performance for the NO2 -detection (Ksv = 0.07 µM-1). The efficiency of the composite was ca. 1.7 and 1.4 times higher than the bare ZnO and the best composite prepared by the physical mixing method, respectively. These results suggested that impregnation method is a suitable method to prepare the PVP/ZnO composites as fluorescence sensor for the NO2 -detection.

  10. Influence of the aluminium impregnation [ Al(NO33] in the beta zeolite over its acidity

    Directory of Open Access Journals (Sweden)

    Francisco José Sánchez Castellanos


    Full Text Available Beta zeolite was impregnated with [ Al(NO33], increasing the aluminium content in increments of 0.05% from 0.00% to 0.25%. A parallel treatment with 0.05% sulphuric acid was also performed; in both cases, methanol was used as solvent (disperse phase. Cation exchange capacity (CEC, ammonia chemisorption, infrared spectroscopy (FIT-IR, scanning electronic microscopy (SEM, X-Ray powder diffraction (XRD, atomic absorption spectroscopy (AAS, titration with sodium hydroxide and nitrogen physisorption at 77K were used to carry out the physical and chemical characterization of the catalysts. Futhermore, the catalysts were employed in the esterification of ethanol with acetic acid, to quantify the effect of aluminium impregnation over the beta zeolite.

  11. Polymer-Based Carbon Monoxide Sensors (United States)

    Homer, M. L.; Shevade, A. V.; Zhou, H.; Kisor, A. K.; Lara, L. M.; Yen, S.-P. S.; Ryan, M. A.


    Polymer-based sensors have been used primarily to detect volatile organics and inorganics; they are not usually used for smaller, gas phase molecules. We report the development and use of two types of polymer-based sensors for the detection of carbon monoxide. Further understanding of the experimental results is also obtained by performing molecular modeling studies to investigate the polymer-carbon monoxide interactions. The first type is a carbon-black-polymer composite that is comprised of a non-conducting polymer base that has been impregnated with carbon black to make it conducting. These chemiresistor sensors show good response to carbon monoxide but do not have a long lifetime. The second type of sensor has a non-conducting polymer base but includes both a porphyrin-functionalized polypyrrole and carbon black. These sensors show good, repeatable and reversible response to carbon monoxide at room temperature.





    An experiment was performed to synchronize estrus in goats by locally prepared progesterone-impregnated sponges and to determine the time of onset and duration of estrus alongwith subsequent fertility rate. The study was conducted from May to December, 2007 at NIAB (Nuclear Institute for Agriculture and Biology), Faisalabad. Polyurethane sponges were prepared with medroxyprogesterone acetate (MAP: 60 mg) and inserted intra-vaginally in a lot of 8 female postpartum goats (Beetal x Dwarf). Two ...

  13. Ageing and Partial Discharge Patterns in Oil-Impregnated Paper and Pressboard Insulation at High Temperature


    R. H. Khawaja; T. R. Blackburn; M. Rehan Arif


    The power transformer is the most expensive, indispensable and arguably the most important equipment item in a power system Insulation failure in transformers can cause long term interruption to supply and loss of revenue and the condition assessment of the insulation is thus an important maintenance procedure. Oil-impregnated transformer insulation consists of mainly organic materials including mineral oil and cellulose-base paper and pressboard. The operating life of cellulose-based insulat...

  14. Isolation of Trichoderma harzianum (Rifai) growing on ferric hydroxide mud impregnated with gas oil

    Energy Technology Data Exchange (ETDEWEB)

    Gudin, C. (Lavera Refinery, France); Chater, K.W.A.


    In northern France, gas oil-impregnated ferric hydroxide mud was found to support fungal growth. The fungus was identified by the Commonwealth Mycological Institute, Kew, with whom a reference culture has been registered. Experiments indicated that its growth resulted from the biodegradation of the gas oil. It is believed that, in this unusual situation, contaminating hydrocarbons may be removed from the environment by microbial activity.

  15. Critical Rate of Thermal Decomposition of Pure and Impregnated Lignocellulosic Materials (United States)

    Chrebet, Tomáš; Balog, Karol


    Contribution deals with monitoring the impact of airflow velocity around the sample, the oven temperature during thermal decomposition and nature of the sample for the minimum mass flux rate needed to initiate flame combustion. We used the samples of lignocellulosic materials, particularly spruce wood, pure cellulose, flax, cellulose impregnated by 5%, 10%, 15% water solution of KHCO3 and by 5%, 10%, 15% water solution of (NH4)2HPO4.

  16. Advances in understanding of osmotic dehydration and vacuum impregnation of fruits


    Tylewicz, Urszula


    Osmotic Dehydration and Vacuum Impregnation are interesting operations in the food industry with applications in minimal fruit processing and/or freezing, allowing to develop new products with specific innovative characteristics. Osmotic dehydration is widely used for the partial removal of water from cellular tissue by immersion in hypertonic (osmotic) solution. The driving force for the diffusion of water from the tissue is provided by the differences in water chemical potential between ...

  17. Impregnated Cobalt, Nickel, Copper and Palladium Oxides on Magnetite: Nanocatalysts for Organic Synthesis


    Pérez Galera, Juana María


    In this manuscript, the application of different nanocatalysts derived from metal oxides impregnated on the surface of the magnetite in different reaction of general interest in Organic Chemistry is described. In the First Chapter, a cobalt derived catalyst was used to study the hydroacylation reaction of azodicarboxylates with aldehydes. In the Second Chapter, a catalyst derived from copper was used to perform different reactions, including homocoupling of terminal alkynes and the subsequent...

  18. Negative plates for dry-charged lead storage batteries. [higher charging capacity when impregnated with tannin solution

    Energy Technology Data Exchange (ETDEWEB)

    Fiedler, V.; Malikova, V.; Weber, H.


    Impregnation of negative plates with acid solutions of sulfomethylated tannins was found to improve the charging properties at low temperatures. Methods for synthesizing tannins are described. Charging capacity at 0/sup 0/ was 7.3A. (RWR)

  19. Effects of tanalith-e impregnation substance on bending strengths and modulus of elasticity in bending of some wood types

    Directory of Open Access Journals (Sweden)

    Hakan Keskin


    Full Text Available The aim of this study was to investigate the effects of impregnation with Tanalith-E on the bending strengths and modulus of elasticity in bending of some wood types. The test samples prepared from beech, oak, walnut, poplar, ash and pine wood materials - that are of common use in the forest products industry of TURKEY - according to TS 345, were treated with according to ASTM D 1413-76 substantially. Un-impregnated samples according to impregnated wood materials, the bending strengths in beech to 6.83%, 5.12% in ash, 5.93% in pine, the elasticity module values to 7.15% in oak and ash, at a rate of 6.58% in the higher were found. The highest values of bending strengths and modulus of elasticity in bending were obtained in beech and ash woods impregnated with Tanalith-E, whereas the lowest values were obtained in the poplar wood.

  20. Prevalent material parameters governing spalling of a slag-impregnated refractory

    Energy Technology Data Exchange (ETDEWEB)

    Blond, E.; Schmitt, N.; Arnould, O.; Hild, F. [LMT-Cachan (ENS de Cachan / CNRS-UMR 8535 / Univ. Paris 6), Cachan (France); Blumenfeld, P. [CRDM / ARCELOR Grande Synthe, Dunkerque (France); Poirier, J. [CRDM / ARCELOR Grande Synthe, Dunkerque (France); CRMHT-CNRS, Orleans (France)


    In steel ladle linings, bauxite refractories in contact with iron and steel slag are subjected to complex loadings. To identify the causes of degradation in different reactor linings, a coupling diagram made up of three poles is established: namely, slag impregnation (I), Thermomechanics (TM) and phase transformations (P). The variation of the microstructure and the gradient of the chemical composition resulting from the (I-P) coupling are characterized by microprobe analyses; a natural impregnation tracer is identified. The (I-T) coupling is studied by modeling the refractory lining behavior subjected to a cyclic thermal loading within the framework of the mechanics of porous continua. Parameters governing the location and amplitude of the maximum pore pressure are obtained and their influences are studied. The analysis of the (TM) pole leads to the identification of a thermo-elasto-viscoplastic model for bauxite in various states of slag impregnation. Numerical simulations show that the stress state developed during the heating stages can induce spalling, probably generated by a localized over-pressure of slag. (orig.)

  1. Impregnation of β-tricalcium phosphate robocast scaffolds by in situ polymerization. (United States)

    Martínez-Vázquez, Francisco J; Perera, Fidel H; van der Meulen, Inge; Heise, Andreas; Pajares, Antonia; Miranda, Pedro


    Ring-opening polymerization of ε-caprolactone (ε-CL) and L-lactide (LLA) was performed to impregnate β-tricalcium phosphate (β-TCP) scaffolds fabricated by robocasting. Concentrated colloidal inks prepared from β-TCP commercial powders were used to fabricate porous structures consisting of a 3D mesh of interpenetrating rods. ε-CL and LLA were in situ polymerized within the ceramic structure by using a lipase and stannous octanoate, respectively, as catalysts. The results show that both the macropores inside the ceramic mesh and the micropores within the ceramic rods are full of polymer in either case. The mechanical properties of scaffolds impregnated by in situ polymerization (ISP) are significantly increased over those of the bare structures, exhibiting similar values than those obtained by other, more aggressive, impregnation methods such as melt-immersion (MI). ISP using enzymatic catalysts requires a reduced processing temperature which could facilitate the incorporation of growth factors and other drugs into the polymer composition, thus enhancing the bioactivity of the composite scaffold. The implications of these results for the optimization of the mechanical and biological performance of scaffolds for bone tissue engineering applications are discussed. Copyright © 2013 Wiley Periodicals, Inc.

  2. Effect of preceramic and Zr coating on impregnation behaviors of SiC ceramic composite (United States)

    Jung, Yang-Il; Kim, Sun-Han; Kim, Hyun-Gil; Park, Jeong-Yong; Koo, Yang-Hyun


    SiC fiber-reinforced ceramic composites were fabricated using a polymer impregnation and pyrolysis process. To develop the low temperature process, the pyrolysis was conducted at 600 °C in air. Both a microstructural observation and a mechanical test were utilized for the evaluation of the impregnation. For the impregnation, two kinds of polycarbosilane having a different degree of cross-linking were used. The level of cross-linking affected the ceramic yield of the composites. The cross-linking under oxygen containing atmosphere resulted in a dense matrix and high density of filling. However, tight bonding between the matrix and fibers in the fully dense composite samples, which was obtained using a cross-linking agent of divinylbenzene, turned out to be deteriorative on the mechanical properties. The physical isolation of fibers from matrix phase in the composites was very important to attain a mechanical ductility. The brittle fracture was alleviated by introducing an interphase coating with metallic Zr. The combination of forming the dense matrix and interphase coating should be a necessary condition for the SiCf/SiC fiber-reinforce composite, and it is practicable by controlling the process parameters.

  3. Are interpretations of other people's arguments value-impregnated? A pilot study among medical students. (United States)

    Juth, Niklas; Nilsonne, Åsa; Lynöe, Niels


    Analogously to Kuhn's and Hanson's understanding of observation as theory-impregnated, we try to test the hypothesis that observation and interpretation might also be value-impregnated. We use a written examination task for medical students who were asked to read and interpret a text where the authors provide arguments pro et contra euthanasia. Afterwards the students were asked to provide their own reflected opinion on the issue. We found that medical students who were against and indecisive provided interpretations of the text which accorded with their own reflected opinions (P = 0.02), indicating that their interpretations were influenced by their own values. When including those who were pro euthanasia, the association was no longer significant. Although the present investigation was a small pilot-study, we obtained partial support for our hypothesis and have adjusted it to read as follows: observations and interpretations might be value-impregnated for respondents who have rather strong value-based attitudes. We think the adjusted hypothesis deserves to be further examined.

  4. Honey in combination with vacuum impregnation to prevent enzymatic browning of fresh-cut apples. (United States)

    Jeon, M; Zhao, Y


    This study evaluated the antioxidative capacity of 13 US Northwest honeys from different floral sources and their anti-browning effect on fresh-cut apples. The inhibitory effect of honey on enzymatic browning of fresh-cut apples were studied by simply immersing apple slices in 10% honey solution for 30 min or vacuum impregnating (vacuum at 75 mmHg for 15 min followed with 30 min restoration at atmospheric pressure) in the same honey solution. The 10% diluted high-fructose corn syrup solution was used as a comparison. The surface color of the apple slices was monitored during 14 days of storage at 3 degrees C and 90% relative humidity. Physicochemical properties of the apples immediately after treatment were also evaluated. Wildflower honey had the darkest color and the highest antioxidative capacity among all test honeys. Vacuum impregnation with honey was more effective in controlling browning discoloration than that of simple immersion treatment. Honey in combination with vacuum impregnating operation may have a great potential for developing high-quality fresh-cut fruits.

  5. Effects of heat treatment on sound absorption coefficients in nanosilver-impregnated and normal solid woods. (United States)

    Esmailpour, Ayoub; Taghiyari, Hamid Reza; Zolfaghari, Habib


    Effects of impregnation with silver nano-suspension as well as heat-treatment on sound absorption coefficients (AC) were studied in tangential direction of five different solid woods based on their importance. AC was measured at two frequencies of 250 and 500 Hz. A 400 ppm nanosuspension was used for the impregnation; silver nanoparticles had a size range of 30-80 nm. Based on the obtained results, the species reacted significantly different in absorbing sound at the two frequencies. Impregnation with nano-suspension substantially decreased AC at the lower frequency of 250 Hz; it did not show any particular trend when AC was measured at the frequency of 500 Hz. Heat treatment significantly increased AC at the frequency of 250 Hz. ACs of mulberry tended to be similar at the two frequencies; in the other four species though, ACs were significantly different. High significant correlations were found in the hardwoods between the ACs measured at the two frequencies.

  6. Study of Volcanic-Ash-Impregnated-Bacteria Filler to the Compressive Strength of Concrete

    Directory of Open Access Journals (Sweden)

    Purwanto Hendry Anjar


    Full Text Available Technology of concrete has been advanced recently to improve the properties of concrete. Utilization of ash as the substitute of cement or filler of concrete also indicates good result in compressive strength concrete in certain amount. Harnessing the bacteria for self-healing concrete has also been successfully performed in order to maintain the destruction of the concrete by itself. Past research indicated that bacteria can be beneficiary to improve the compressive strength, absorption, permeability, and so on. In this paper, Bacillus Altitudinis was extracted from the karst (source from the limestone mountain and bred through liquid media to be impregnated inside the volcanic ash. The impregnated bacteria in volcanic ash were used as the filler to the concrete mixture with the proportion of filler varied from 1%, 1.5% and 2% to the weight of cement. Mechanical properties of the concrete specimen showed that the compressive strength reached its best when the filler proportion was 1.5%. The absorption referred analogously to the increment of compressive strength due to the success of filling the void inside the concrete. Based on compression test to all the concrete specimens, there was enhancement about 18% and the average absorption can be abated around 23%. Future research due to some drawbacks turning up is the need of developing another media for bacteria to live and making sure the exact amount of bacteria impregnated to the media so that the desired advance of concrete compressive strength can be acquired.

  7. Theoretical impact of insecticide-impregnated school uniforms on dengue incidence in Thai children. (United States)

    Massad, Eduardo; Amaku, Marcos; Coutinho, Francisco Antonio Bezerra; Kittayapong, Pattamaporn; Wilder-Smith, Annelies


    Children carry the main burden of morbidity and mortality caused by dengue. Children spend a considerable amount of their day at school; hence strategies that reduce human-mosquito contact to protect against the day-biting habits of Aedes mosquitoes at schools, such as insecticide-impregnated uniforms, could be an effective prevention strategy. We used mathematical models to calculate the risk of dengue infection based on force of infection taking into account the estimated proportion of mosquito bites that occur in school and the proportion of school time that children wear the impregnated uniforms. The use of insecticide-impregnated uniforms has efficacy varying from around 6% in the most pessimistic estimations, to 55% in the most optimistic scenarios simulated. Reducing contact between mosquito bites and human hosts via insecticide-treated uniforms during school time is theoretically effective in reducing dengue incidence and may be a valuable additional tool for dengue control in school-aged children. The efficacy of this strategy, however, is dependent on the compliance of the target population in terms of proper and consistent wearing of uniforms and, perhaps more importantly, the proportion of bites inflicted by the Aedes population during school time.

  8. Theoretical impact of insecticide-impregnated school uniforms on dengue incidence in Thai children

    Directory of Open Access Journals (Sweden)

    Eduardo Massad


    Full Text Available Background: Children carry the main burden of morbidity and mortality caused by dengue. Children spend a considerable amount of their day at school; hence strategies that reduce human–mosquito contact to protect against the day-biting habits of Aedes mosquitoes at schools, such as insecticide-impregnated uniforms, could be an effective prevention strategy. Methodology: We used mathematical models to calculate the risk of dengue infection based on force of infection taking into account the estimated proportion of mosquito bites that occur in school and the proportion of school time that children wear the impregnated uniforms. Principal findings: The use of insecticide-impregnated uniforms has efficacy varying from around 6% in the most pessimistic estimations, to 55% in the most optimistic scenarios simulated. Conclusions: Reducing contact between mosquito bites and human hosts via insecticide-treated uniforms during school time is theoretically effective in reducing dengue incidence and may be a valuable additional tool for dengue control in school-aged children. The efficacy of this strategy, however, is dependent on the compliance of the target population in terms of proper and consistent wearing of uniforms and, perhaps more importantly, the proportion of bites inflicted by the Aedes population during school time.


    Directory of Open Access Journals (Sweden)

    N. Marchitan


    Full Text Available This work describes an investigation of the process of reactive ion-exchange separation of tartaric acid from model systems with macroreticular resin AmberliteXAD2 impregnated with liquid ion-exchanger Amberlite LA-2 in batch equipment.The condition of Amberlite XAD2 impregnation process was investigated. Freudlichand Langmuir equations were verified and values of enthalpy, entropy and Gibbs energy were calculated. This article is an extended abstract of a communicationpresented at the Conference Ecological Chemistry 2012.

  10. Expression, Purification and Characterization of GMZ2'.10C, a Complex Disulphide-Bonded Fusion Protein Vaccine Candidate against the Asexual and Sexual Life-Stages of the Malaria-Causing Plasmodium falciparum Parasite

    DEFF Research Database (Denmark)

    Mistarz, Ulrik H; Singh, Susheel K; Nguyen, Tam T T N


    PURPOSE: Production and characterization of a chimeric fusion protein (GMZ2'.10C) which combines epitopes of key malaria parasite antigens: glutamate-rich protein (GLURP), merozoite surface protein 3 (MSP3), and the highly disulphide bonded Pfs48/45 (10C). GMZ2'.10C is a potential candidate...... for a multi-stage malaria vaccine that targets both transmission and asexual life-cycle stages of the parasite. METHODS: GMZ2'.10C was produced in Lactococcus lactis and purified using either an immunoaffinity purification (IP) or a conventional purification (CP) method. Protein purity and stability...

  11. Investigation of the metabolic consequences of impregnating spinach leaves with trehalose and applying a pulsed electric field. (United States)

    Dymek, Katarzyna; Panarese, Valentina; Herremans, Els; Cantre, Dennis; Schoo, Rick; Toraño, Javier Sastre; Schluepmann, Henriette; Wadso, Lars; Verboven, Pieter; Nicolai, Bart M; Dejmek, Petr; Gómez Galindo, Federico


    The impregnation of leafy vegetables with cryoprotectants using a combination of vacuum impregnation (VI) and pulsed electric fields (PEF) has been proposed by our research group as a method of improving their freezing tolerance and consequently their general quality after thawing. In this study, we have investigated the metabolic consequences of the combination of these unit operations on spinach. The vacuum impregnated spinach leaves showed a drastic decrease in the porosity of the extracellular space. However, at maximum weight gain, randomly located air pockets remained, which may account for oxygen-consuming pathways in the cells being active after VI. The metabolic activity of the impregnated leaves showed a drastic increase that was further enhanced by the application of PEF to the impregnated tissue. Impregnating the leaves with trehalose by VI led to a significant accumulation of trehalose-6-phosphate (T6P), however, this was not further enhanced by PEF. It is suggested that the accumulation of T6P in the leaves may increase metabolic activity, and increase tissue resistance to abiotic stress. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Inkjet Impregnation for Tailoring Air Electrode Microstructure to Improve Solid Oxide Cells Performance

    KAUST Repository

    Da’as, Eman H.


    The urge to lower the operating temperature of solid oxide cells (SOCs) to the intermediate ranges between 500-700°C motivated the research into impregnation processes, which offer highly efficient SOC air electrodes at low operating temperatures. Lack of controllability and reproducibility of this technique in the conventional way is still considered as an inadequacy for industrialization since it is performed manually. Therefore, inkjet-printing technology was proposed as an adequate approach to perform scalable and controllable impregnation for SOC air electrodes, which in turn leads to low operating temperatures. Composite LSM-ionic conductive air electrodes of weight ratio 1:2 were fabricated by inkjet impregnation of lanthanum strontium manganite (La0.8Sr0.2MnO3) precursor nitrates onto a porous ionic conductive backbone structure. First, porous yttria stabilized zirconia (8YSZ) substrates prepared by tape casting were used to study the influence of the printing parameters on the lateral dispersion and penetration of LSM ink inside the pores. XRD analysis confirmed the formation of LSM phase after calcination at 800°C for 2 h, while SEM revealed the formation of LSM nanostructures. It has been found by optical microscope observations that the spacing between the drops and the substrate temperature have a significant role in controlling the printing process. Next, the optimized printing parameters were applied in the inkjet impregnation of the LSM ink into porous YSZ electrodes that were spin coated on both sides of dense YSZ layers. LSM-YSZ composite air electrodes achieved an area specific resistance (ASR) of around 0.29 Ω.cm2 at 700°C. The performance of LSM-YSZ composite electrodes was influenced by the microstructure and the thickness, and by the electrode/electrolyte interface characteristics. As a result, the enhancement in LSM-YSZ composite electrode performance was observed due to the better percolation in LSM, YSZ and oxygen diffusion. Finally

  13. Long-lasting permethrin impregnated uniforms: A randomized-controlled trial for tick bite prevention. (United States)

    Vaughn, Meagan F; Funkhouser, Sheana Whelan; Lin, Feng-Chang; Fine, Jason; Juliano, Jonathan J; Apperson, Charles S; Meshnick, Steven R


    Because of frequent exposure to tick habitats, outdoor workers are at high risk for tick-borne diseases. Adherence to National Institute for Occupational Safety and Health-recommended tick bite prevention methods is poor. A factory-based method for permethrin impregnation of clothing that provides long-lasting insecticidal and repellent activity is commercially available, and studies are needed to assess the long-term effectiveness of this clothing under field conditions. To evaluate the protective effectiveness of long-lasting permethrin impregnated uniforms among a cohort of North Carolina outdoor workers. A double-blind RCT was conducted between March 2011 and September 2012. Subjects included outdoor workers from North Carolina State Divisions of Forestry, Parks and Recreation, and Wildlife who worked in eastern or central North Carolina. A total of 159 volunteer subjects were randomized, and 127 and 101 subjects completed the first and second years of follow-up, respectively. Uniforms of participants in the treatment group were factory-impregnated with long-lasting permethrin whereas control group uniforms received a sham treatment. Participants continued to engage in their usual tick bite prevention activities. Incidence of work-related tick bites reported on weekly tick bite logs. Study subjects reported 1,045 work-related tick bites over 5,251 person-weeks of follow-up. The mean number of reported tick bites in the year prior to enrollment was similar for both the treatment and control groups, but markedly different during the study period. In our analysis conducted in 2013, the effectiveness of long-lasting permethrin impregnated uniforms for the prevention of work-related tick bites was 0.82 (95% CI=0.66, 0.91) and 0.34 (95% CI=-0.67, 0.74) for the first and second years of follow-up. These results indicate that long-lasting permethrin impregnated uniforms are highly effective for at least 1 year in deterring tick bites in the context of typical tick bite

  14. Fe-Impregnated Mineral Colloids for Peroxide Activation: Effects of Mineral Substrate and Fe Precursor. (United States)

    Li, Yue; Machala, Libor; Yan, Weile


    Heterogeneous iron species at the mineral/water interface are important catalysts for the generation of reactive oxygen species at circumneutral pH. One significant pathway leading to the formation of such species arises from deposition of dissolved iron onto mineral colloids due to changes in redox conditions. This study investigates the catalytic properties of Fe impregnated on silica, alumina, and titania nanoparticles (as prototypical mineral colloids). Fe impregnation was carried out by immersing the mineral nanoparticles in dilute Fe(II) or Fe(III) solutions at pH 6 and 3, respectively, in an aerobic environment. The uptake of iron per unit surface area follows the order of nTiO2 > nAl2O3 > nSiO2 for both types of Fe precursors. Impregnation of mineral particles in Fe(II) solutions results in predominantly Fe(III) species due to efficient surface-mediated oxidation. The catalytic activity of the impregnated solids to produce hydroxyl radical (·OH) from H2O2 decomposition was evaluated using benzoic acid as a probe compound under dark conditions. Invariably, the rates of benzoic acid oxidation with different Fe-laden particles increase with the surface density of Fe until a critical density above which the catalytic activity approaches a plateau, suggesting active Fe species are formed predominantly at low surface loadings. The critical surface density of Fe varies with the mineral substrate as well as the aqueous Fe precursor. Fe impregnated on TiO2 exhibits markedly higher activity than its Al2O3 and SiO2 counterparts. The speciation of interfacial Fe is analyzed with diffuse reflectance UV-vis analysis and interpretation of the data in the context of benzoic oxidation rates suggests that the surface activity of the solids for ·OH generation correlates strongly with the isolated (i.e., mononuclear) Fe species. Therefore, iron dispersed on mineral colloids is a significant form of reactive iron surfaces in the aquatic environment.

  15. Industrial grade 2D molybdenum disulphide (MoS2): an in vitro exploration of the impact on cellular uptake, cytotoxicity, and inflammation (United States)

    Moore, Caroline; Movia, Dania; Smith, Ronan J.; Hanlon, Damien; Lebre, Filipa; Lavelle, Ed C.; Byrne, Hugh J.; Coleman, Jonathan N.; Volkov, Yuri; McIntyre, Jennifer


    The recent surge in graphene research, since its liquid phase monolayer isolation and characterization in 2004, has led to advancements which are accelerating the exploration of alternative 2D materials such as molybdenum disulphide (MoS2), whose unique physico-chemical properties can be exploited in applications ranging from cutting edge electronic devices to nanomedicine. However, to assess any potential impact on human health and the environment, the need to understand the bio-interaction of MoS2 at a cellular and sub-cellular level is critical. Notably, it is important to assess such potential impacts of materials which are produced by large scale production techniques, rather than research grade materials. The aim of this study was to explore cytotoxicity, cellular uptake and inflammatory responses in established cell-lines that mimic different potential exposure routes (inhalation, A549; ingestion, AGS; monocyte, THP-1) following incubation with MoS2 flakes of varying sizes (50 nm, 117 nm and 177 nm), produced by liquid phase exfoliation. Using high content screening (HCS) and Live/Dead assays, it was established that 1 µg ml-1 (for the three different MoS2 sizes) did not induce toxic effects on any of the cell-lines. Confocal microscopy images revealed a normal cellular morphology in all cases. Transmission electron microscopy (TEM) confirmed the uptake of all MoS2 nanomaterials in all the cell-lines, the MoS2 ultimately locating in single membrane vesicles. At such sub-lethal doses, inflammatory responses are observed, however, associated, at least partially, with the presence of lipopolysaccharide endotoxin in nanomaterial suspensions and surfactant samples. Therefore, the inflammatory response of the cells to the MoS2 or endotoxin contamination was interrogated using a 10-plex ELISA which illustrates cytokine production. The experiments carried out using wild-type and endotoxin hyporesponsive bone marrow derived dendritic cells confirmed that the

  16. Comparison of the Acidity of Heteropolyacids Encapsulated in or Impregnated on SBA-15

    Directory of Open Access Journals (Sweden)

    Pinto Teresa


    Full Text Available Heteropolyacids (HPA immobilized onto SBA-15 silica were prepared by two different ways using either impregnation or encapsulation methodologies. Two Keggin-type HPA, H3PW12O40 and H4SiW12O40 were considered in this study. The resulting hybrid materials were fully characterized by N2 adsorption-desorption isotherms, XRD, FT-IR, Raman, diffuse reflectance UV-Vis spectroscopies and 31P MAS NMR. All characterization methods showed that at room temperature the catalysts contained well-dispersed and intact Keggin units throughout the solid. The catalytic activity of these solids was investigated in the isomerization of n-hexane. The impregnated and encapsulated phosphotungstic catalysts performed similarly in catalysis showing that the amount of active sites was nearly the same in both catalysts. On the contrary, the tungstosilicic encapsulated material was completely inactive while its impregnated counterpart was even more active than the phosphotungstic derived catalysts. The acidity of the solids was measured by various methods: microcalorimetry of ammonia adsorption, ammonia desorption followed by Temperature Programmed Desorption (TPD and DRIFT/GC-MS and pyridine adsorption followed by infrared spectroscopy. Only pyridine adsorption and ammonia desorption followed by DRIFT/GC-MS agreed with the catalytic data. Ammonia adsorption followed by microcalorimetry was not able to differentiate between the four catalysts while the TPD experiments led to unreliable results, as not only the evolved ammonia but also other molecules such as water were taken into account in the measurements. The behavior difference between the encapsulated silico- and phosphotungstic acids was explained by a more pronounced encapsulation in the case of silicon.

  17. Flexural Strength Comparison of Silorane- and Methacrylate-Based Composites with Pre-impregnated Glass Fiber. (United States)

    Doozandeh, Maryam; Alavi, Ali Asghar; Karimizadeh, Zahra


    Sufficient adhesion between silorane/methacrylate-based composites and methacrylate impregnated glass fiber increases the benefits of fibers and enhances the mechanical and clinical performance of both composites. The aim of this study was to evaluate the compatibility of silorane and methacrylate-based composites with pre-impregnated glass fiber by using flexural strength (FS) test. A total of 60 bar specimens were prepared in a split mold (25×2×2 mm) in 6 groups (n=10). In groups 1 and 4 (control), silorane-based (Filtek P90) and nanohybrid (Filtek Z350) composites were placed into the mold and photopolymerized with a high-intensity curing unit. In groups 2 and 5, pre-impregnated glass fiber was first placed into the mold and after two minutes of curing, the mold was filled with respective composites. Prior to filling the mold in groups 3 and 6, an intermediate adhesive layer was applied to the glass fiber. The specimens were stored in distilled water for 24 hours and then their flexural strength was measured by 3 point bending test, using universal testing machine at the crosshead speed of 1 mm/min. Two-way ANOVA and post-hoc test were used for analyzing the data (pglass fiber, and application of intermediate adhesive layer .The lowest FS was obtained in Filtek P90 alone. Cohesive failure in composite was the predominant failure in all groups, except group 5 in which adhesive failure between the composite and fiber was exclusively observed. Significant improvement in FS was achieved for both composites with glass fiber. Additional application of intermediate adhesive layer before composite build up seems to increase FS. Nanohybrid composite showed higher FS than silorane-based composite.

  18. Development of a New Environment-conscious Transformer Impregnated with Palm Fatty Acid Ester (PFAE) (United States)

    Hikosaka, Tomoyuki; Yamazaki, Akina; Hatta, Yasunori; Koide, Hidenobu; Kanoh, Takaaki; Suzuki, Takashi; Yamada, Junichi; Uemura, Shingo

    We have developed a new environment-conscious transformer impregnated with vegetable based insulating oil which called PFAE (Palm Fatty Acid Ester). PFAE has 0.6 times less viscosity and 1.3 times higher dielectric constant compared to mineral oil. This means that a PFAE immersed transformer has better cooling efficiency and better insulating performance in paper-and-oil composite insulation systems, resulting in size reduction in comparison to conventional mineral oil immersed transformers. In this paper, insulating performance of lead to plane electrode models, cooling performance of a PFAE immersed transformer, and the result of analytical study of dissolved gas for abnormal diagnosis are described.

  19. A new resin system for the impregnation and bonding of large magnet coils

    CERN Document Server

    Evans, D


    ATLAS is an instrument which forms part of the Large Hadron Collider, a high energy physics experiment which is under construction at CERN, Geneva, Switzerland. The properties of the candidate resin systems developed for the impregnation of the Atlas End Cap Toroid magnets are presented. The resin systems contain a blend of two resins; a low viscosity Bisphenol F resin, with a long chain aliphatic epoxide resin. An aromatic amine curing agent was used. It was found that increased additions of the long chain aliphatic epoxide resin resulted in longer useable life, lower glass transition temperature, lower modulus, higher toughness and higher bond strength at 4 K. (4 refs).

  20. Iodine-impregnated incision drape and bacterial recolonization in simulated total knee arthroplasty

    DEFF Research Database (Denmark)

    Milandt, Nikolaj; Nymark, Tine; Jørn Kolmos, Hans


    bacteria in the surgical field of an arthroplasty, and surgery in general, may increase the infection risk. We investigated whether IIID use increases bacterial recolonization compared to no drape use under conditions of simulated total knee arthroplasty (TKA). Methods - 20 patients scheduled for TKA were......Background and purpose - Iodine-impregnated incision drapes (IIIDs) are used to prevent surgical site infection (SSI). However, there is some evidence to suggest a potential increase in SSI risk as a result of IIID use, possibly from promotion of skin recolonization. A greater number of viable...

  1. Cluster Classification of Partial Discharges in Oil-impregnated Paper Insulation

    Directory of Open Access Journals (Sweden)

    SURESH, S. D. R.


    Full Text Available Recognition of multiple partial discharge (PD sources in high voltage equipment has been a challenging task until now. The work reported here, aims to recognize multiple PD sources in oil-impregnated paper using Cluster Analysis (CA and Fuzzy Logic (FL. The typical sources of PD in transformer are identified and the corresponding single source PD defect laboratory models are fabricated. From the measured PD signals, the necessary statistical parameters are extracted by applying CA for classification. A Fuzzy based algorithm has been developed to recognize single source PDs. The developed algorithm has also been applied to recognize multiple PD sources.

  2. Elaboration of nickel-impregnated over hexagonal mesoporous materials and their catalytic application

    Directory of Open Access Journals (Sweden)

    M. Laribi


    Full Text Available Hexagonal mesoporous silicas with different nickel contents have been synthesized and characterized by several techniques such as N2 physical adsorption, elemental analysis, XRD, TEM and temperature programmed reduction (TPR. In fact, the nickel-impregnated over hexagonal mesoporous silicas showed both high activity and high selectivity for Friedel–Crafts alkylations of benzene with benzyl chloride. The kinetics of the reaction over these catalysts have been investigated and the reaction has been extended to other substrates like toluene, p-xylene, anisole, naphthalene and methylnaphthalene.

  3. Improvement of operational properties of shell limestone building materials by polysulfide solution impregnation

    Directory of Open Access Journals (Sweden)

    MASSALIMOV Ismail Alexandrovich


    Full Text Available The data of studies on the effectiveness of impregnation with polysulfide solutions of shell limestone used as facing and wall material, as well as for the manufacture of road products are presented. Modification of the limestone with the impregnating composition «Akvastat» created by the authors which is sulfur-containing water-based solution of calcium polysulfide containing alcohols and surfactants, can significantly reduce water absorption and increase durability of limestone. Impregnating composition on the basis of calcium polysulfide possesses density of 1.22–1.24 g/cm3, the infiltrant penetrates into the pore structure of limestone to a depth of 4 cm or more, depending on the density and structure of the sample. While the material is drying, sulfur nanoparticles are crystallized from the polysulfide solution in its pores. They partially fill pore space and form protective durable insoluble hydrophobic coating that impedes the penetration of water into the pores of the limestone, but preserves its vapor permeability, which is important for wall and decoration materials. The evaluation of protective coatings was performed with laser particle size analyzer, scanning probe microscope and a diffractometer. It showed that the average size of the particles forming the protective coating is in the range of 20–25 nm, the particles shape is spherical, the particles are elemental sulfur with orthorhombic structure of the crystal lattice. The processing of shell limestone with calcium polysulphide solution provides formation of coating based on nanosized sulfur on the surface of stone pores. The coating partially fills the pore space and, as it is hydrophobic, reduces the water absorption of the samples by a factor of 5–8, increases their average density by 22–27%, strength in 1,2–1,3 times, the softening factor by 6–19%, that makes possible to predict the increase of the durability of building materials based on shell limestone to 1

  4. Biocidal efficacy of silver-impregnated contact lens storage cases in vitro. (United States)

    Dantam, Jaya; Zhu, Hua; Stapleton, Fiona


    Silver-impregnated contact lens (CL) storage cases are designed to reduce microbial contamination during use, but there are limited data on their effectiveness. This study evaluated early antimicrobial activity of silver-impregnated CL cases and silver-release characteristics in vitro. Three silver-impregnated CL storage cases-MicroBlock (CIBA Vision, Atlanta, GA), i-clean (Sauflon Pharmaceuticals Ltd., London, UK), and Nano-case (Marietta Vision, Marietta, GA)-were evaluated. Test organisms included the ISO14729 panel and two clinical isolates, Delftia acidovorans and Stenotrophomonas maltophilia. Each well of the case was challenged with 2 mL of the organism in phosphate-buffered saline at 10(3), 10(4), 10(5), and 10(6) CFU/mL. Survivors were recovered after 6, 10, and 24 hours' incubation at 25°C. Inductively coupled plasma mass spectrometry was used to quantify the release of silver from the cases for similar incubation conditions and for time points up to 28 days. Significant differences in antimicrobial activity were observed between cases (P ≤ 0.001). Activity was apparent only after 24 hours. MicroBlock showed the highest activity against Pseudomonas aeruginosa (2.4 ± 0.5 log reduction at 10(6)), Serratia marcescens (3.3 ± 0.9 log reduction at 10(6)), D. acidovorans (2.8 ± 0.1 log reduction at 10(3)), and Fusarium solani (0.5 ± 0.2 at 10(3)). The i-clean case was most effective against Staphylococcus aureus (5.4 ± 1.1 log reduction), whereas Nano-case showed the greatest activity against S. maltophilia (0.2 ± 0.3 log reduction at 10(3)). MicroBlock was the only case to demonstrate silver release over 28 days. Current silver-impregnated CL storage cases show variation in their in vitro antimicrobial activity. Broadly, the MicroBlock case demonstrated robust activity against most Gram-negative bacteria, whereas the i-clean case was more effective against S. aureus. Silver-release data suggest different modes of action for different cases.

  5. Impregnation of Scots pine and beech with tannin solutions: effect of viscosity and wood anatomy in wood infiltration. (United States)

    Tondi, G; Thevenon, M F; Mies, B; Standfest, G; Petutschnigg, A; Wieland, S

    The impregnation process of Scots pine and beech samples with tannin solutions was investigated. The two materials involved in the process (impregnation solution and wood samples) are studied in depth. Viscosity of mimosa tannin solutions and the anatomical aspect of beech and Scots pine were analysed and correlated. The viscosity of tannin solutions presents a non-newtonian behaviour when its pH level increases, and in the case of addition of hexamine as a hardener, the crosslinking of the flavonoids turns out to be of great importance. During the impregnation of Scots pine (Pinus sylvestris L.) and beech (Fagus sylvatica L.), the liquid and solid uptakes were monitored while taking into consideration the different conditions of the impregnation process. This method allowed to identify the best conditions needed in order to get a successful preservative uptake for each wooden substrate. The penetration mechanism within the wood of both species was revealed with the aid of a microscopic analysis. Scots pine is impregnated through the tracheids in the longitudinal direction and through parenchyma rays in the radial direction, whereas in beech, the penetration occurs almost completely through longitudinal vessels.

  6. Antibiotic-Impregnated Central Venous Catheters Do Not Change Antibiotic Resistance Patterns. (United States)

    Turnbull, Isaiah R; Buckman, Sara A; Horn, Christopher B; Bochicchio, Grant V; Mazuski, John E


    Antibiotic-impregnated central venous catheters (CVCs) decrease the incidence of infection in high-risk patients. However, use of these catheters carries the hypothetical risk of inducing antibiotic resistance. We hypothesized that routine use of minocycline and rifampin-impregnated catheters (MR-CVC) in a single intensive care unit (ICU) would change the resistance profile for Staphylococcus aureus. We reviewed antibiotic susceptibilities of S. aureus isolates obtained from blood cultures in a large urban teaching hospital from 2002-2015. Resistance patterns were compared before and after implementation of MR-CVC use in the surgical ICU (SICU) in August 2006. We also compared resistance patterns of S. aureus obtained in other ICUs and in non-ICU patients, in whom MR-CVCs were not used. Data for rifampin, oxacillin, and clindamycin were available for 9,703 cultures; tetracycline resistance data were available for 4,627 cultures. After implementation of MR-CVC use in the SICU, rifampin resistance remained unchanged, with rates the same as in other ICU and non-ICU populations (3%). After six years of use of MR-CVCs in the SICU, the rate of tetracycline resistance was unchanged in all facilities (1%-3%). The use of MR-CVCs was not associated with any change in S. aureus oxacillin-resistance rates in the SICU (66% vs. 60%). However, there was a significant decrease in S. aureus clindamycin resistance (59% vs. 34%; p resistance of S. aureus isolates to rifampin or tetracyclines.

  7. The effect of loading and particle size on the oxygen reaction in CGO impregnated Pt electrodes

    DEFF Research Database (Denmark)

    Lund, Anders; Hansen, Karin Vels; Jacobsen, Torben


    Porous platinum electrodes impregnated with Gd x Ce1−x O2−δ (CGO) are investigated to characterise how nano-sized CGO grains affect the oxygen reaction. Impedance measurements were performed at temperatures between 450 and 750 °C and at oxygen partial pressures of 0.2 and 5 × 10−5 bar for electro......Porous platinum electrodes impregnated with Gd x Ce1−x O2−δ (CGO) are investigated to characterise how nano-sized CGO grains affect the oxygen reaction. Impedance measurements were performed at temperatures between 450 and 750 °C and at oxygen partial pressures of 0.2 and 5 × 10−5 bar...... for electrodes with various CGO loadings and electrodes annealed at various temperatures. The morphology was characterised by scanning electron microscopy and the CGO grain size was determined from X-ray diffraction peak broadening. The results showed that the polarisation resistance decreased with increasing...... CGO loading and increasing annealing temperature. CGO facilitates transport of oxygen ions thereby increasing the effective triple-phase boundary....

  8. Steady state performance of copper impregnated Ni/PTFE gas diffusion electrode in alkaline fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Al-Saleh, M.A.; Gultekin, S.; Al-Zakri, A.S.; Khan, A.A.A. [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Dept. of Chemical Engineering


    The steady-state polarization measurements on a Raney nickel gas diffusion electrode impregnated with copper oxide were carried out in a half-cell setup with 25% KOH electrolyte solution. Pure hydrogen gas was used at a pressure of 1.2 bars in the temperature range of 25-75{sup o}C. The results were compared with almost the same electrode without copper. There was an improvement in the performance of the electrode impregnated with about 8 wt% Cu. This improvement is much more pronounced at higher temperatures and higher current densities. The spherical Raney catalyst grain model was used to determine the kinetic parameters such as exchange current density (i{sub o}) and charge transfer coefficient ({alpha}) for the electrode. The values found for the exchange current densities at various temperatures were 6.6 x 10{sup -6} -3.1 x 10{sup -4} mA cm{sup -2} and for the charge transfer coefficient was about 0.6. The exchange current density followed an exponential relation with temperature. The apparent activation energy for the electrode reaction at zero mV overvoltage was found to be lower (28 kJ mol{sup -1}) than that reported in the literature (32 kJ mol{sup -1}). The higher values for the exchange current densities and lower values for the activation energies are indication of better performance of the electrode used in this study. (Author)

  9. Antiseptic-impregnated central venous catheters: their evaluation in burn patients. (United States)

    Ramos, G; Bolgiani, A; Patiño, O; Prezzavento, G; Guastavino, P; Durlach, R; Fernandez Caniggia, L; Benaim, F


    Central venous catheter-related infections are an important source of morbidity and mortality in burn patients. Antiseptic impregnated catheters have been recommended to prevent infections related to central venous lines in high-risk patients who require short-term catheters. This prospective, randomized, and controlled study compared the efficacy of standard and antiseptic devices in reducing catheter-related infections in burn patients. Twenty-two patients were included in the study with an average age of 47.6 yr and an average burned total body surface area of 38.7%. Thirty-eight silver-sulphadiazine, chlorhexidine catheters were compared with 40 non-antiseptic catheters. No differences in bacteraemia or colonization rates were observed between standard and antiseptic-coated catheters. Antiseptic catheters were more effective in reducing S. epidermidiscolonization than standard catheters (4% vs 31%, p < 0.01). However, Gram-negative bacilli were responsible more often than Gram-positive cocci for catheter tip colonization (53% vs 46%) and they were responsible for all the bacteraemias (5.1%) related to catheters in the present study. We conclude that antiseptic-impregnated catheters could be more effective for Gram-positive cocci and could therefore be less effective in patients with high Gram-negative bacilli bloodstream infection prevalence, as burn patients are.

  10. Theoretical simulation of CO2 capture in organic cage impregnated with polyoxometalates. (United States)

    Gao, Jingyuan; Li, Wenliang; Zhang, Jingping


    To explore the adsorption and separation properties of CO2 in a novel material consisting of a series of polyoxometalates (POMs) impregnated within supramolecular porous catenane (shorted as SPC), grand canonical Monte Carlo (GCMC) simulations and ab initio calculations were used. GCMC simulations showed this impregnation can enhance CO2 /CH4 (or CO2 /N2 ) selectivity almost 30 times compared to the bare SPC due to the strong interaction of CO2 with the nPOMs@SPC structures. And, the loading of CO2 inhibits the adsorption of CH4 (or N2 ) as CO2 occupying the preferred adsorption sites. Furthermore, the effect of number, mass, and volume of POMs inserted in SPC on CO2 /CH4 (or CO2 /N2 ) selectivity over large pressure range was investigated in detail. Additionally, the accurate ab initio calculations further confirmed our GCMC simulations. As a result, the proposed nPOMs@SPC structures are promising candidates for CO2 /N2 and CO2 /CH4 separations. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  11. Highly fluorescent peptide nanoribbon impregnated with Sn-porphyrin as a potent DNA sensor. (United States)

    Parayil, Sreenivasan Koliyat; Lee, Jooran; Yoon, Minjoong


    Highly fluorescent and thermo-stable peptide nanoribbons (PNRs) were fabricated by solvothermal self-assembly of a single peptide (D,D-diphenyl alanine peptides) with Sn-porphyrin (trans-dihydroxo[5,10,15,20-tetrakis(p-tolyl)porphyrinato] Sn(IV) (SnTTP(OH)2)). The structural characterization of the as-prepared nanoribbons was performed by transmitting electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM), FT-IR and Raman spectroscopy, indicating that the lipophilic Sn-porphyrins are impregnated into the porous surface formed in the process of nanoribbon formation through intermolecular hydrogen bonding of the peptide main chains. Consequently the Sn-porphyrin-impregnated peptide nanoribbons (Sn-porphyrin-PNRs) exhibited typical UV-visible absorption spectrum of the monomer porphyrin with a red shifted Q-band, and their fluorescence quantum yield was observed to be enhanced compared to that of free Sn-porphyrin. Interestingly the fluorescence intensity and lifetimes of Sn-porphyrin-PNRs were selectively affected upon interaction with nucleotide base sequences of DNA while those of free Sn-porphyrins were not affected by binding with any of the DNA studied, indicating that DNA-induced changes in the fluorescence properties of Sn-porphyrin-PNRs are due to interaction between DNA and the PNR scaffold. These results imply that Sn-porphyrin-PNR will be useful as a potent fluorescent protein analogue and as a biocompatible DNA sensor.

  12. Electron microscopy studies of natural and synthetic zeolites impregnated with uranyl dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Acosta, Dwight R.; T-Olguin, Maria; Solache, Marcos; Bosch, Pedro; Bulbulian, Silvia [Universidad Nacional Autonoma de Mexico, Mexico City (Mexico). Inst. de Fisica; Asomoza, Max [Instituto Nacional de Investigaciones Nucleares, Mexico City (Mexico). Dept. de Quimica Nuclear


    Full text. The use of Y zeolite and erionite to remove uranyl dioxide ions from aqueous solution is focussed on catalysis and energy transfer problems but it can be oriented to recovery uranyl dioxide ions, among other radioactive compounds. The samples impregnated with uranyl dioxide at several concentrations and contact times were studied using conventional, high resolution and scanning electron microscopy in order to detect changes as consequence of contact with a radioactive material and to verify mechanical stability of zeolites. Also X ray diffraction, thermal analysis, neutron activation were used to characterize the samples at several steps of treatment. The crystallinity of zeolites was maintained only when using dilute uranyl nitrate solution (up to 0.0100 N for y zeolite and 0.0300 N for erionite). The samples impregnated with highest nitrate concentrations partially lost their crystallinity. From selected area electron diffraction pattern, lattice parameter variations were detected and from high resolution electron microscopy localization of uranyl ions in and on zeolite structure was determined. Surface modification in zeolites was observed by scanning electron microscopy just for samples with long contact time with radioactive solutions. (author)

  13. Influence of impregnation method on metal retention of CCB-treated wood in slow pyrolysis process. (United States)

    Kinata, Silao Espérance; Loubar, Khaled; Bouslamti, Amine; Belloncle, Christophe; Tazerout, Mohand


    In the present work, the effects of copper, chromium and boron on the pyrolysis of wood and their distribution in the pyrolysis products were investigated. For this, the wood has been impregnated with chromium-copper-boron (CCB). In addition, to describe the effects of impregnation method, vacuum-pressure and dipping methods were also conducted. Thermogravimetric analysis (TGA) results show that an increase in the final residue and decrease in degradation temperature on both methods of treated wood compared to untreated wood. Then, slow pyrolysis experiments were carried out in a laboratory reactor. The mass balance of pyrolysis products is confirmed by TGA. Furthermore, the concentration of metals in the final residue is measured by inductively coupled plasma mass spectroscopy (ICP-MS). The results show that the final residue contains more than 45% of the initial amount of metal present in the treated wood. The phenomenon is more pronounced with vacuum-pressure treated wood. The heating values of pyrolysis products were analyzed. The heating value of charcoal obtained from treated and untreated wood is approximately same. But the heating value of tar from untreated wood is higher than the heating value of the tar from treated wood. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Removal of arsenic from toxic ash after combustion of impregnated wood (United States)

    Ottosen, L. M.; Pedersen, A. J.; Kristensen, I. V.; Ribeiro, A. B.


    ln the next ten years the amounts of waste wood impregnated with Cu, Cr and As (CCA) is expected to increase dramatically. Mixed with municipal solid waste for incineration the wood constitutes a problem because As emission is not hindered through common flue gas treatment. Furthermore the ashes will contain higher concentrations of Cu, Cr and As. In different countries initiatives has been taken or are implemented to sort the impregnated wood from other waste and handle the wood separately. This handling can involve combustion in special plants. This paper deals with electrodialytic treatment of ash from combustion of CCA treated wood. The total concentrations in the ash were very high: 69gCu/kg, 62gCr/kg and 35gAs/kg. A SEM/EDX analysis showed that Cr was mainly build into the matrix structure of the ash. Cu, too, but some Cu was also precipitated on the surface of the particles. As, on the other hand, was only found associated with Ca and thus probably in a soluble form. As is the main problem of the ash due to the high toxicity and mobility and thus the treatment aims at removing this element. It was shown that during 5 days of electrodialytic treatment 92% As could be removed.

  15. Wood impregnated with metal chelates dissolved in organic media tested for termite resistance

    Directory of Open Access Journals (Sweden)

    Lara Maistrello


    Full Text Available Wood manufactured products are subjected to biological decay due to fungi and insects. The use of copper chelates as biocides was proposed, due to their high stability which minimizes copper leaching into the environment. Considering the remarkable effectiveness showed by copper chelates on brown rot fungi, zinc and copper salicylate complexes were prepared in order to have metal chelates soluble in organic media available. The present study aimed at evaluating these metal chelates complexes as preservative agents for wood treatment against termites. Trials were performed on Reticulitermes lucifugus (Rossi and Kalotermes flavicollis (Fabricius. Results showed that in both termite species wood consumption was significantly lower on Cu-chelates treated samples compared to untreated wood, whereas the wood slices impregnated with Zn-chelates and the organic media alone gave an intermediate response. Interestingly, in one case solvent-impregnated wood was significantly more attractive than untreated wood for both species and further investigations are being carried out to clarify this behaviour.

  16. Occupational exposure to chromium, copper and arsenic during work with impregnated wood in joinery shops. (United States)

    Nygren, O; Nilsson, C A; Lindahl, R


    CCA-impregnated timber contains copper, chromium and arsenic (CCA), and occupational exposure to wood dust as well as the CCA compounds may occur in work with such timber. Dust from commercially available impregnated wood has been found to contain hexavalent chromium, which is regarded as a carcinogen. Apart from determinations of the total amounts of the CCA compounds, specific determination of hexavalent chromium is therefore essential. Selective methods have been applied for control of the work environment in six joinery shops. The mean exposure to wood dust was found to be below 1 mg m-3. The mean airborne concentration of arsenic around various types of joinery machines was in the range from 0.54 to 3.1 micrograms m-3. No hexavalent chromium was detected in any samples and no increased concentrations of arsenic were found in urine from the workers. The presence of arsenic in the work-room air must be considered for appropriate assessment of the occupational environment in joinery shops.

  17. Interphase formation of a resin transfer molded silica phenolics composites subjected to dynamic impregnation process (United States)

    Wang, Baichen; Huang, Yudong


    In this study interphase formation of a resin transfer molded (RTMed) silica-phenolics composites subjected to dynamic impregnation process was investigated. The solvent effect on the interphase formation of silica fiber-phenolics composites was evaluated. UV-vis spectra, XPS and electron paramagnetic resonance (EPR) techniques were used to characterize the competitive adsorption of the components of phenolics solution onto silica reinforcement surfaces. Interlaminar shear strength (ILSS) and void content of silica-phenolics composites were also measured. It has been found that phenolics forms distribution gradient over RTM mold with respect to isomeric composition under the effect of solvent, which result, to varying extent, in the inhomogeneity of void content and thus ILSS of a final product. For the first time, it has been shown that the RTM process of silica-phenolics composites is highly solvent-dependent. Our work gives an insight into the role of organic solvent in a RTM solution impregnation processing and provides useful information and trends relating microscopic to macroscopic behavior.

  18. Preparation, characterization and antimicrobial study of a hydrogel (soft contact lens) material impregnated with silver nanoparticles. (United States)

    Fazly Bazzaz, Bibi Sedigheh; Khameneh, Bahman; Jalili-Behabadi, Mohammad-mehdi; Malaekeh-Nikouei, Bizhan; Mohajeri, Seyed Ahmad


    Contact lenses that incorporate antimicrobial properties may reduce the risk for microbial-associated adverse events for lens wearers. The aim of this study was to assess the antimicrobial effects of silver nanoparticles (NP) when impregnated in a hydrogel material. Hydrogel disks, used as a proxy for soft contact lenses, were prepared with silver NPs to add an antimicrobial effect to the polymer. Six groups of disks were created, each with a different concentration of silver NPs. The antimicrobial effect of the hydrogels against Pseudomonas aeruginosa (ATCC15442) and Staphylococcus aureus (ATCC6538) was evaluated at 6, 24, 48 and 72 h. Silver NP concentrations ranged from 20.71 to 98.06 μg/disk. All groups demonstrated excellent antibacterial effects against P. aeruginosa at each time point. After 6h all disks didn't exhibit desirable antibacterial activity against S. aureus; whereas except those with 20.71 μg silver NPs showed antibacterial activity at 24h and only the disks with 57.13 and 98.06 μg silver NPs showed antimicrobial activity at 48 and 72 h. The development of contact lenses made of a silver NP-impregnated hydrogel material may bring antimicrobial effects sufficient to decrease the risk of microbial-related adverse events for lens wearers. Copyright © 2013 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  19. Mechanical properties of composites made of hybrid fabric impregnated with silica nanoparticles and epoxy resin (United States)

    Kordani, N.; Alizadeh, M.; Lohrasby, F.; Khajavi, R.; Baharvandi, H. R.; Rezanejad, M.; Ahmadzadeh, M.


    In this study, the mechanical properties of composites will be examined which were made from Kenaf and hybrid fabric with a simple structure that was coated with epoxy resin and nano silica particles. This fabric cotton has a different situation in terms of yarn score and the type of fiber that is used in textiles. Nano silica particles of 200 nm, polyethylene glycol with 200 molecular weights and ethanol with mechanical weight molecular with ratio of 6:1 will be mixed. Suspension of 60% was chosen according to the silica particles. The D6264 standard test for concentrated force was carried out through the cone edge to determine the strength of each of the samples. Increasing of resistance against penetration in the Kenaf samples from the raw until impregnated with the shear thickening fluid is less than the hybrid samples. Slippage of the fibers with the change of round edge indenter to cone edge indenter has changed. Penetration by cone edge to the cloth is done with lower force and it shows the effect of slippage of fibers on the resistance of the penetration. Samples impregnated with the shear thickening fluid in comparison with epoxy resin have lower resistance. Slippage of natural fibers in comparison with synthetic fibers is lower and on the other hand the average of friction between fibers in the natural fibers is more than synthetic fibers.

  20. Applicability of Vacuum Impregnation to Modify Physico-Chemical, Sensory and Nutritive Characteristics of Plant Origin Products—A Review (United States)

    Radziejewska-Kubzdela, Elżbieta; Biegańska-Marecik, Róża; Kidoń, Marcin


    Vacuum impregnation is a non-destructive method of introducing a solution with a specific composition to the porous matrices of fruit and vegetables. Mass transfer in this process is a result of mechanically induced differences in pressure. Vacuum impregnation makes it possible to fill large volumes of intercellular spaces in tissues of fruit and vegetables, thus modifying physico-chemical properties and sensory attributes of products. This method may be used, e.g., to reduce pH and water activity of the product, change its thermal properties, improve texture, color, taste and aroma. Additionally, bioactive compounds may be introduced together with impregnating solutions, thus improving health-promoting properties of the product or facilitating production of functional food. PMID:25244012

  1. Synthesis H-Zeolite catalyst by impregnation KI/KIO3 and performance test catalyst for biodiesel production (United States)

    Widayat, W.; Rizky Wicaksono, Adit; Hakim Firdaus, Lukman; Okvitarini, Ndaru


    The objective of this research is to produce H-catalyst catalyst that was impregnated with KI/KIO3. The catalyst was analyzed about surface area, X-Ray Diffraction (XRD) and performance test of catalyst for biodiesel production. An H-Zeolite catalyst was synthesized from natural zeolite with chemical treatment processing, impregnation KI/KIO3 and physical treatment. The results shows that the surface area of the catalyst by 27.236 m2/g at a concentration of 5% KI. XRD analysis shows peak 2-θ at 23.627o indicating that KI was impregnated on H-zeolite catalyst. The catalyst was tested in production of biodiesel using palm oil with conventional methods for 3 hour at temperature of 70-80 oC. The result for conversion Fatty Acid Methyl Ester (FAME) reached maximum value on 87.91% under production process using catalyst 5% KIO3-H zeolite.

  2. Platinum incorporation in the Na Y zeolite through impregnation method, and characterization by XRD, FTIR and nitrogen adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, A.S.; Sousa, B.V.; Andrade, A.C.C.; Rodrigues, M.G.F. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Centro de Ciencias e Tecnologia. Unidade Academica de Engenharia Quimica], e-mail:, e-mail:, e-mail:; Rangel, M.C. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Estudos em Cinetica e Catalise


    Supported metal catalysts are widely used in petroleum refining, chemical and petroleum industries. These catalysts are important in ammonia synthesis, conversion of hydrocarbons with water vapor to synthesis gas, reforming, hydrocracking, ... Platinum has long been used in cracking, hydrogenation and dehydrogenation processes. The aim of this project is the Na Y zeolitic sample preparation through impregnation for incipient humidity, with 0,5% concentration of platinum, aiming its use as a catalyst in the steam reforming reaction. The characterization techniques used were: X Rays Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR) and Nitrogen Adsorption (BET Method). From the obtained results through the techniques mentioned previously it is possible to evidence that the platinum impregnation process did not change the Na Y zeolite structure. Through the superficial specific area (BET) it was possible to observe that the platinum impregnation process caused a decrease in the specific area due to the reduction to the accessibility to the micropores of the zeolitic structure. (author)

  3. Effects of acid impregnated steam explosion process on xylose recovery and enzymatic conversion of cellulose in corncob. (United States)

    Fan, Xiaoguang; Cheng, Gang; Zhang, Hongjia; Li, Menghua; Wang, Shizeng; Yuan, Qipeng


    Corncob residue is a cellulose-rich byproduct obtained from industrial xylose production via dilute acid hydrolysis processes. Enzymatic hydrolysis of cellulose in acid hydrolysis residue of corncob (AHRC) is often less efficient without further pretreatment. In this work, the process characteristics of acid impregnated steam explosion were studied in conjunction with a dilute acid process, and their effects on physiochemical changes and enzymatic saccharification of corncob residue were compared. With the acid impregnated steam explosion process, both higher xylose recovery and higher cellulose conversion were obtained. The maximum conversion of cellulose in acid impregnated steam explosion residue of corncob (ASERC) reached 85.3%, which was 1.6 times higher than that of AHRC. Biomass compositional analysis showed similar cellulose and lignin content in ASERC and AHRC. XRD analysis demonstrated comparable crystallinity of ASERC and AHRC. The improved enzymatic hydrolysis efficiency was attributed to higher porosity in ASERC, measured by mercury porosimetry. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. [Potentially toxic antibiotics concentrations after administration using impregnated dressing in a severe burned patient: A case report]. (United States)

    Dupouey, Julien; Wiramus, Sandrine; Albanese, Jacques; Guilhaumou, Romain; Blin, Olivier


    Severe burned patients present high risk of skins infections, frequently due to Pseudomonas aeruginosa. Impregnated dressings with amikacin or colistin could be a good alternative to obtain effective concentration directly at the infected site. Therapeutic drug monitoring for these antibiotics is currently recommended after an intravenous administration to obtain effective and non-toxic plasmatic concentrations. However, data are lacking about systemic exposition and risk of toxicity after an administration with impregnated dressings. We report the case of a severe burned patient with cutaneous infection treated with amikacin and colistin impregnated dressings, for which plasmatic pharmacokinetic profiles were performed. Copyright © 2016 Société française de pharmacologie et de thérapeutique. Published by Elsevier Masson SAS. All rights reserved.

  5. Impact of impregnation time and chip size on sugar yield in pretreatment of softwood for ethanol production. (United States)

    Monavari, Sanam; Galbe, Mats; Zacchi, Guido


    Efficient pretreatment is necessary to make the wood-to-ethanol process more feasible. In this study, chips of different sizes were impregnated with SO(2) and steam-pretreated. Dilute-acid pretreatment together with subsequent enzymatic hydrolysis resulted in solubilization of between 69% and 73% of the fermentable sugars (glucose and mannose) in the raw material for the combinations of impregnation times and chip sizes investigated. Shorter impregnation times resulted in slightly lower mannose yields for the larger chips, probably due to poor diffusion of the catalyst. Small differences in glucose yield after enzymatic hydrolysis showed that the overall glucose yield was slightly higher for the smaller chips, however, whether the increased energy demand and cost of size reduction is compensated for by the higher yield, requires techno-economical evaluations.

  6. Esthetic rehabilitation of severely decayed primary incisors using glass impregnated fiber post as post and core: A treatment option

    Directory of Open Access Journals (Sweden)

    Ajay Kumar Kapoor


    Full Text Available Restoration of primary incisors, which have been severely damaged by extensive caries or trauma, is a difficult task for the pediatric dentist. Primary teeth dictate the physical appearance, and their structural affects leads to loss of esthetics compromised mastication, poor phonetics, development of aberrant habits, neuromuscular imbalance, and difficulty in social and psychological adjustment of the child. Case description: This case report discusses the restoration of severely decayed primary maxillary incisors using composite resin restoration reinforced with glass impregnated post in anterior teeth in a 4-year-old male patient. The use of intracanal posts in endodontically treated teeth improves the retention of a eventual restoration. The use of impregnated fiberglass post together with flowable composite offers an alternative where all components are bonded together to form a firmly attached restoration. This technique of glass impregnated composite resin post and core has shown promising results and has presented pediatric dentists with an additional treatment option.

  7. Antimicrobial-impregnated central venous catheters for prevention of catheter-related bloodstream infection in newborn infants. (United States)

    Balain, Munisha; Oddie, Sam J; McGuire, William


    Central venous catheter-related bloodstream infection is an important cause of mortality and morbidity in newborn infants cared for in neonatal units. Potential strategies to prevent these infections include the use of central venous catheters impregnated with antimicrobial agents. To determine the effect of antimicrobial-impregnated central venous catheters in preventing catheter-related bloodstream infection in newborn infants. We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 8), MEDLINE (1966 to September 2015), EMBASE (1980 to September 2015), CINAHL (1982 to September 2015), conference proceedings and previous reviews. Randomised or quasi-randomised controlled trials comparing central venous catheters impregnated or coated with any antibiotic or antiseptic versus central venous catheters without antibiotic or antiseptic coating or impregnation in newborn infants. We extracted data using the standard methods of the Cochrane Neonatal Group, with independent evaluation of risk of bias and data extraction by two review authors. We found only one small trial (N = 98). This trial found that silver zeolite-impregnated umbilical venous catheters reduced the incidence of bloodstream infection in very preterm infants (risk ratio 0.11, 95% confidence interval 0.01 to 0.87; risk difference -0.17, 95% CI -0.30 to -0.04; number needed to treat for benefit 6, 95% CI 3 to 25]. Although the data from one small trial indicates that antimicrobial-impregnated central venous catheters might prevent catheter-related bloodstream infection in newborn infants, the available evidence is insufficient to guide clinical practice. A large, simple and pragmatic randomised controlled trial is needed to resolve on-going uncertainty.

  8. Infection rates of rifampin/gentamicin-coated Titan Coloplast penile implants. Comparison with Inhibizone-impregnated AMS penile implants. (United States)

    Dhabuwala, Chirpriya; Sheth, Sheila; Zamzow, Brent


    It is a common practice to soak Titan(®) Coloplast penile implants in antibiotic solution prior to implantation. Experience with Inhibizone impregnation suggests that rifampin coating significantly reduces infection rates of penile implant surgery. In this article we describe the results of coating Titan Coloplast penile implants with rifampin/gentamicin solution. To compare infection rates of Titan(®) Coloplast penile implants coated with vancomycin/gentamycin, rifampin/gentamicin, and Inhibizone-impregnated American Medical Systems (AMS) penile implants. Chart review was done for all Mentor/Coloplast and AMS implant surgeries performed at our center between the dates January 1, 2002 and February 8, 2010. Infection rates for Titan(®) Coloplast penile implants coated with vancomycin/gentamycin, rifampin/gentamicin, and Inhibizone-impregnated (AMS) penile implants were compared. Infection rates for penile implants coated with different antibiotics. Infection rates for Titan(®) Coloplast penile implants coated with vancomycin/gentamycin and Inhibizone-impregnated (AMS) penile implants was 4.4% and 1.3%, respectively (P = 0.05). None of the rifampin/gentamicin-coated Titan(®) Coloplast penile implants have developed infection. Rifampin is the common antibiotic both in rifampin/gentamicin-coated Coloplast implants and Inhibizone(®) . The infection rate in this combined rifampin/gentamicin-coated Titan Coloplast implants and Inhibizone-coated AMS implants group was 0.63% (P = 0.03). Both rifampin/gentamicin-coated Titan(®) Coloplast penile implants and Inhibizone-impregnated (AMS) penile implants appear to have lower infection rates compared with vancomycin/gentamycin-coated Titan(®) Coloplast penile implants The present study does not suggest superiority of rifampin/gentamicin-coated Titan(®) Coloplast penile implants or Inhibizone-impregnated (AMS) penile implants but we strongly suggest that all Titan(®) Coloplast penile implants should be coated with

  9. Electromagnetic Properties of Multifunctional Composites Based on Glass Fiber Prepreg and Ni/Carbon Fiber Veil


    Silveira, Daniel Consoli; Gomes, Newton; Rezende, Mirabel Cerqueira; Botelho, Edson Cocchieri


    ABSTRACT: Multifunctional composites combine structural and other physicochemical properties, with major applications in aeronautical, space, telecommunication, automotive, and medical areas. This research evaluates electromagnetic properties of multifunctional composites based on glass fiber woven fabric pre-impregnated with epoxy resin laminated together carbon fiber non-woven veil metalized with Ni. In this way, searching for possible application as radar absorbing structures or electromag...

  10. Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures (United States)

    Aines, Roger D.


    A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

  11. Cavitation as a Precursor to Breakdown of Mass-Impregnated HVDC Cables

    Energy Technology Data Exchange (ETDEWEB)

    Evenset, Gunnar


    Thermal cycling has proven to be a critical test for mass-impregnated HVDC cables. The dielectric strength of the insulation is significantly reduced during the first part of the cooling. This decrease of the dielectric strength limits the development of mass-impregnated cables for higher operating voltages and higher power transfer capacities. The decrease of the dielectric strength during cooling has been assumed to be caused by formation of cavities in the mass because the thermal contraction of the mass is larger than that of the paper. Cavities have previously been observed in thermally cycled cables, but their actual formation and growth have not been studied. The fact that breakdown usually occurs a few hours into the cooling period indicates that the dynamics of the growth is important. This work studies the dynamic phenomena occurring in mass-impregnated cables during thermal cycling. In experiments on a system of mass and insulating paper, cavities were observed near the paper surface, probably caused by heterogeneous nucleation. Knowing the tensile stress at cavity formation is important because it controls the size of the cavities and the distance between independently formed cavities in a cable insulation. A test cell was designed to investigate cavitation in models of lapped insulation. The formation, growth and collapse of the cavities could be visually observed while the insulation was electrically stressed and partial discharges were measured. The first cavity generally formed in one of the butt gaps and grew both along the butt gap and into the mass layers between the papers towards adjacent butt gaps. When the cavity between the papers grew into an adjacent butt gap, the gas/vapour filled channel connecting the butt gaps was closed. In this way, one cavity grew into several butt gaps. The extent of cavities between the papers was observed to depend on the interfacial pressure. Considerable less tension is required to suck the menisci of a cavity

  12. Application of Boron Oxide as a Protective Surface Treatment to Decrease the Air Reactivity of Carbon Anodes

    Directory of Open Access Journals (Sweden)

    Ramzi Ishak


    Full Text Available The oxidation of a carbon anode with air and CO2 occurs during the electrolysis of alumina in Hall-Héroult cells, resulting in a significant overconsumption of carbon and dusting. Boron is well known to decrease the rate of this reaction for graphite. In this work, the application of boron oxide has been investigated to evaluate its inhibition effect on the air oxidation reaction, and to provide an effective protection for anodes. Different methods of impregnation coating have been explored. Impregnated anode samples were gasified under air at 525 °C according to the standard measurement methods. X-ray tomography was used to obtain the microstructural information of the samples before and after air-burning tests. The impregnated samples showed a very low oxidation reaction rate and dust generation.

  13. Effects of Carbonization Temperature and Component Ratio on Electromagnetic Interference Shielding Effectiveness of Woodceramics

    Directory of Open Access Journals (Sweden)

    Yubo Tao


    Full Text Available Woodceramics were fabricated in a vacuum through carbonization of wood powder impregnated with phenol formaldehyde (PF resin. The effects of carbonization temperature and mass ratio of wood/resin on electromagnetic interference (EMI shielding effectiveness (SE and morphology of woodceramics were explored. The PF resin made wood cell walls have the characteristics of glassy carbon. Wood axial tracheid and ray cells were filled with more glassy carbon by increasing addition of PF resin. Moreover, the increase of carbonization temperature was beneficial to improving SE. Woodceramics (mass ratio 1:1 obtained at 1000 °C presented a medium SE level between 30 MHz and 1.5 GHz.

  14. Densification Behavior and Performances of C/C Composites Derived from Various Carbon Matrix Precursors (United States)

    Shao, H. C.; Xia, H. Y.; Liu, G. W.; Qiao, G. J.; Xiao, Z. C.; Su, J. M.; Zhang, X. H.; Li, Y. J.


    Three types of carbon/carbon (C/C) composites were manufactured by densifying the needled carbon fiber preform through resin and pitch impregnation/carbonization repeatedly, as well as propylene pyrolysis by chemical vapor infiltration plus carbonization after the resin impregnation/carbonization. The densification behavior and performances (involving electric, thermal, and mechanical properties, as well as impurity) of the C/C composites were investigated systematically. The results show that besides the processing and testing conditions, the electric resistivity, thermal conductivity (TC), coefficient of thermal expansion (CTE), strength, and fracture, as well as impurity content and composition of the C/C composites were closely related to the fiber orientation, interfacial bonding between carbon fiber and carbon matrix, material characteristics of the three precursors and the resulting matrix carbons. In particular, the resin-carbon matrix C/C (RC/C) composites had the highest electric resistivity, tensile, and flexural strength, as well as impurity content. Meanwhile, the pitch-carbon matrix C/C (PC/C) composites possessed the highest TC and CTE in the parallel and vertical direction. And most of the performances of pyro-carbon/resin carbon matrix C/C composites were between those of the RC/C and PC/C composites except the impurity content.

  15. Development and Characterization of Novel Polyurethane Films Impregnated with Tolfenamic Acid for Therapeutic Applications (United States)

    Sheraz, Muhammad Ali; Rehman, Ihtesham ur


    The present study deals with the preparation of polyurethane (PU) films impregnated with a nonsteroidal anti-inflammatory drug, tolfenamic acid (TA). Solvent evaporation technique has been employed for the preparation of TA-PU films in two different ratios of 1 : 2 and 1 : 5 in Tetrahydrofuran (THF) or THF-ethanol mixtures. The prepared films were characterized using X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and release studies. The results indicate transformation of crystalline TA to its amorphous form. The degree of crystallinity changes both by increasing the polymer concentration and solvent used for the film preparations. The release profiles of TA were also found to be affected, showing a decrease from approximately 50% to 25% from 1 : 2 to 1 : 5 ratios, respectively. PMID:24073394

  16. The split calvarial bone graft donor site: the effects of surgicel and hydroxyapatite impregnated with collagen. (United States)

    Thaller, S R; Kim, S; Tesluk, H; Kawamoto, H


    Surgicel, which is commonly used as a hemostatic agent in clinical practice, is basically composed of oxidized regenerated cellulose. Skoog followed by Thilander and Stenstrom are credited with initially describing the use of Surgicel as a subperiosteal implant that could stimulate new bone formation in the closure of secondary palatal fistulae. Encouraged by these previous studies, we decided to investigate the effect of Surgicel and a new implant material, hydroxyapatite impregnated with collagen, on the split calvarial bone graft donor site. To do this, we used adult New Zealand White rabbits as our experimental model. Our study demonstrated histological evidence of both an increased quantity and earlier bony reformation, eventually reconstituting the surgical defect in the split calvarial bone graft donor site treated with Surgicel. Additionally, we found that this alloplastic implant material has potential in the reconstruction of the donor defect in selected patients.

  17. Nanostructured Wood Hybrids for Fire-Retardancy Prepared by Clay Impregnation into the Cell Wall. (United States)

    Fu, Qiliang; Medina, Lilian; Li, Yuanyuan; Carosio, Federico; Hajian, Alireza; Berglund, Lars A


    Eco-friendly materials need "green" fire-retardancy treatments, which offer opportunity for new wood nanotechnologies. Balsa wood (Ochroma pyramidale) was delignified to form a hierarchically structured and nanoporous scaffold mainly composed of cellulose nanofibrils. This nanocellulosic wood scaffold was impregnated with colloidal montmorillonite clay to form a nanostructured wood hybrid with high flame-retardancy. The nanoporous scaffold was characterized by scanning electron microscopy and gas adsorption. Flame-retardancy was evaluated by cone calorimetry, whereas thermal and thermo-oxidative stabilities were assessed by thermogravimetry. The location of well-distributed clay nanoplatelets inside the cell walls was confirmed by energy-dispersive X-ray analysis. This unique nanostructure dramatically increased the thermal stability because of thermal insulation, oxygen depletion, and catalytic charring effects. A coherent organic/inorganic charred residue was formed during combustion, leading to a strongly reduced heat release rate peak and reduced smoke generation.

  18. In vivo diabetic wound healing potential of nanobiocomposites containing bamboo cellulose nanocrystals impregnated with silver nanoparticles. (United States)

    Singla, Rubbel; Soni, Sourabh; Patial, Vikram; Kulurkar, Pankaj Markand; Kumari, Avnesh; S, Mahesh; Padwad, Yogendra S; Yadav, Sudesh Kumar


    In diabetes, hyperglycemic state immensely hinders the wound healing. Here, nanobiocomposites (NCs) developed by impregnation of in situ prepared silver nanoparticles in the matrix of bamboo cellulose nanocrystals were investigated for their ability to hasten the progress of healing events in streptozotocin induced diabetic mice model. Wounds treated with topically applied NCs (hydrogels) showed full recovery (98-100%) within 18days post wounding in contrast to the various control groups where incomplete healing (88-92%) was noticed. Biochemical estimations documented a marked decrease in the levels of pro-inflammatory cytokines IL-6 and TNF-α leading to decreased inflammation in NCs treated mice. Significantly increased expression of collagen and growth factors (FGF, PDGF, VEGF) upon NCs treatment resulted in improved re-epithelialization, vasculogenesis and collagen deposition as compared to control groups. Hence, developed nanobiocomposites showcased potential to serve as highly effective and biocompatible wound dressings for diabetic patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Ecosystem protection by effluent bioremediation: silver nanoparticles impregnation in a textile fabrics process (United States)

    Durán, Nelson; Marcato, Priscyla D.; Alves, Oswaldo L.; Da Silva, João P. S.; De Souza, Gabriel I. H.; Rodrigues, Flávio A.; Esposito, Elisa


    This work studied a bioremediation process of silver nanoparticles with the bacterium Chromobacterium violaceum. These nanoparticles were obtained from several washes of cotton fabrics impregnated with silver nanoparticles produced by the fungus Fusarium oxysporum. The optimized growth of C. violaceum for silver nanoparticles bioremediation was obtained. The effluents of wash process of the cotton fabric were efficiently treated with C. violaceum. This treatment was based on biosorption which was very efficient for the elimination of silver nanoparticles remaining in the wash water. The bacteria after biosorption were morphologically transformed, but the normal morphology after a new culture was completely restored. The process also allowed the recovery of silver material that was leached into the effluent for a reutilization avoiding any effect to the eco-environment.

  20. System and method for preventing stator permanent magnet demagnetization during vacuum pressure impregnation

    Energy Technology Data Exchange (ETDEWEB)

    Raminosoa, Tsarafidy; Alexander, James Pellegrino; EL-Refaie, Ayman Mohamed Fawzi


    A permanent magnet electrical machine includes a stator having conductive windings wound thereon and one or more permanent magnets embedded in the stator. A magnetic keeper element is positioned on the stator so as to form a magnetic flux path with the permanent magnets, with the magnetic keeper element closing the magnetic flux path of the permanent magnets by providing a low reluctance flux path to magnetic flux generated by the permanent magnets. A vacuum pressure impregnation (VPI) process is performed on the stator to increase a thermal conductivity of the windings, with the VPI process including a curing step that is performed at a selected temperature. The magnetic keeper element sets an operating point of the permanent magnets to an internal flux density level above a demagnetization threshold associated with the selected temperature at which the curing step is performed.

  1. Comparison among Different pH Values of Rhodamine B Solution Impregnated into Mesoporous Silica

    Directory of Open Access Journals (Sweden)

    Juliana Jorge


    Full Text Available We studied the behavior of different pH values of Rhodamine B solution impregnated into pores of mesoporous silica, through structural characterization techniques, such as scanning electron microscopy and porosity measurements, and spectroscopic characterization techniques, such as infrared and luminescence spectroscopy; in order to applications in luminescence. Because, Rhodamine B is an interesting xanthene dye whose optical properties depend of many factors, dye concentration and pH values. MSU-4 type mesoporous silica has been synthesized with Tween 60 surfactant as directing-structure agent and tetraethyl orthosilicate (Si(OEt4, TEOS as silica source. The mesoporous structures doped with dyes are promissory materials for several applications, for example, optical sensors and biomarkers.

  2. Plasma-assisted reduction of silver ions impregnated into a natural zeolite framework (United States)

    Osonio, Airah P.; Vasquez, Magdaleno R.


    A green, dry, and energy-efficient method for the fabrication of silver-zeolite (AgZ) composite via 13.56 MHz radio-frequency plasma reduction is demonstrated. Impregnation by soaking and ion-exchange deposition were performed to load the silver ions (Ag+) into the sodium-zeolite samples. Characterization was performed by optical emission spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller analyses. Results indicate the successful reduction of Ag+ to its metallic state on the surface of the zeolite with a mean diameter of 165 nm. This plasma-induced reduction technique opens possibilities in several areas including catalysis, adsorption, water treatment, and medicine.

  3. Ecosystem protection by effluent bioremediation: silver nanoparticles impregnation in a textile fabrics process

    Energy Technology Data Exchange (ETDEWEB)

    Duran, Nelson, E-mail:; Marcato, Priscyla D. [Universidade Estadual de Campinas, Biological Chemistry Laboratory, Instituto de Quimica (Brazil); Alves, Oswaldo L. [Universidade Estadual de Campinas, Solid State Chemistry Laboratory, Instituto de Quimica (Brazil); Silva, Joao P. S. Da; Souza, Gabriel I. H. De [Universidade de Mogi das Cruzes, Biological Chemistry and Biotechnology Laboratory, Environmental Sciences Center (Brazil); Rodrigues, Flavio A. [Universidade de Mogi das Cruzes, Material Chemistry Laboratory, Biochemical Research Center (Brazil); Esposito, Elisa [Universidade de Mogi das Cruzes, Biological Chemistry and Biotechnology Laboratory, Environmental Sciences Center (Brazil)


    This work studied a bioremediation process of silver nanoparticles with the bacterium Chromobacterium violaceum. These nanoparticles were obtained from several washes of cotton fabrics impregnated with silver nanoparticles produced by the fungus Fusarium oxysporum. The optimized growth of C. violaceum for silver nanoparticles bioremediation was obtained. The effluents of wash process of the cotton fabric were efficiently treated with C. violaceum. This treatment was based on biosorption which was very efficient for the elimination of silver nanoparticles remaining in the wash water. The bacteria after biosorption were morphologically transformed, but the normal morphology after a new culture was completely restored. The process also allowed the recovery of silver material that was leached into the effluent for a reutilization avoiding any effect to the eco-environment.

  4. Crystal deposition patterns from evaporating sessile drops on superhydrophobic and liquid impregnated surfaces (United States)

    McBride, Samantha; Dash, Susmita; Varanasi, Kripa; Varanasi Group Team


    Accelerated corrosion and scale buildup near oceans is partially due to deposition of salty sea mist onto ships, cars, and building structures. Many corrosion preventative measures are expensive, time intensive, and/or have negative impacts on the environment. One solution is the use of specific surfaces that are engineered for scale resistance. In this work, we show that we can delay crystallization and reduce scale adhesion on specifically engineered liquid impregnated surfaces (LIS). The low contact angle hysteresis of the LIS results in a sliding contact line of the saline droplet during evaporation, and the elevated energy barrier of the smooth liquid interface delays crystallization. Experiments conducted on surfaces with different wettability also demonstrate the corresponding influence in controlling salt crystal polymorphism.

  5. Development and Characterization of Novel Polyurethane Films Impregnated with Tolfenamic Acid for Therapeutic Applications

    Directory of Open Access Journals (Sweden)

    Hilal Istanbullu


    Full Text Available The present study deals with the preparation of polyurethane (PU films impregnated with a nonsteroidal anti-inflammatory drug, tolfenamic acid (TA. Solvent evaporation technique has been employed for the preparation of TA-PU films in two different ratios of 1 : 2 and 1 : 5 in Tetrahydrofuran (THF or THF-ethanol mixtures. The prepared films were characterized using X-Ray Diffraction (XRD, Differential Scanning Calorimetry (DSC, Fourier Transform Infrared Spectroscopy (FTIR, Scanning Electron Microscopy (SEM, and release studies. The results indicate transformation of crystalline TA to its amorphous form. The degree of crystallinity changes both by increasing the polymer concentration and solvent used for the film preparations. The release profiles of TA were also found to be affected, showing a decrease from approximately 50% to 25% from 1 : 2 to 1 : 5 ratios, respectively.

  6. The Effect of the Melt Viscosity and Impregnation of a Film on the Mechanical Properties of Thermoplastic Composites

    Directory of Open Access Journals (Sweden)

    Jong Won Kim


    Full Text Available Generally, to produce film-type thermoplastic composites with good mechanical properties, high-performance reinforcement films are used. In this case, films used as a matrix are difficult to impregnate into tow due to their high melt viscosity and high molecular weight. To solve the problem, in this paper, three polypropylene (PP films with different melt viscosities were used separately to produce film-type thermoplastic composites. A film with a low melt viscosity was stacked so that tow was impregnated first and a film with a higher melt viscosity was then stacked to produce the composite. Four different composites were produced by regulating the pressure rising time. The thickness, density, fiber volume fraction (Vf, and void content (Vc were analyzed to identify the physical properties and compare them in terms of film stacking types. The thermal properties were identified by using differential scanning calorimetry (DSC and dynamical mechanical thermal analysis (DMTA. The tensile property, flexural property, interlaminar shear strength (ILSS, and scanning electron microscopy (SEM were performed to identify the mechanical properties. For the films with low molecular weight, impregnation could be completed fast but showed low strength. Additionally, the films with high molecular weight completed impregnation slowly but showed high strength. Therefore, appropriate films should be used considering the forming process time and their mechanical properties to produce film-type composites.

  7. Detection of antibodies to human immunodeficiency virus (HIV) in eluates from whole blood impregnated filter paper discs

    DEFF Research Database (Denmark)

    Lindhardt, B O; Bygbjerg, Ib Christian; Ulrich, K


    A method for elution of HIV antibodies from whole blood or serum impregnated filter paper discs was developed. The results from testing of 73 eluates in an enzyme linked immunosorbent assay and the immunoblotting test agreed with the results obtained by ordinary serum testing. Significant loss...

  8. Bacterial transmission from lens storage cases to contact lenses - Effects of lens care solutions and silver impregnation of cases

    NARCIS (Netherlands)

    Vermeltfoort, Pit B. J.; Hooymans, Johanna M. M.; Busscher, Henk J.; van der Mei, Henny C.


    The killing efficacies of multipurpose lens care solutions on planktonic and biofilm bacteria grown in polypropylene contact lens storage cases with and without silver impregnation and effects on bacterial transmission from storage cases to silicone hydrogel contact lenses were investigated. For

  9. Influence of vacuum impregnation and pulsed electric field on the freezing temperature and ice propagation rates of spinach leaves (United States)

    Efforts are currently directed towards improving the quality of sensitive tissues of fruits and vegetables after freezing and thawing. One of the methods under investigation is the combination of vacuum impregnation (VI) with cryoprotectants and pulsed electric field (PEF) applied to the plant tiss...

  10. Effect of PF impregnation and surface densification on the mechanical properties of small-scale wood laminated poles (United States)

    Huaqiang Yu; Chung Y. Hse; Zehui Jiang


    The wood poles in the United States are from high-valued trees that are becoming more expensive and less available. Wood laminated composite poles (LCP) are a kind of alternative to solid poles. Considerable interest has developed in last century in the resin impregnation and wood surface densification to improve its physical and mechanical properties. In this...

  11. Characterisation of the Polyethylene Glycol Impregnation of the Swedish Warship Vasa and one of the Danish Skuldelev Viking Ships

    DEFF Research Database (Denmark)

    Mortensen, M.N.; Egsgaard, Helge; Hvilsted, Søren


    The Swedish l7th century warship Vasa and the Danish Skuldelev Viking ships from the 1 lth century were impregnated with polyethylene glycol (PEG) in the 1960s. The molecular weight, amount and integrity of this PEG were investigated at a range of depths below the wood surface. Large amounts of P...... is hygroscopic....

  12. Reducing the moisture effect on the creep deformation of wood by an irradiation-induced polymer impregnation method (United States)

    Chia, L. H. L.; Boey, F. Y. C.; Teoh, S. H.

    This paper reports an attempt to reduce the sensitivity of creep deformation to moisture adsorption by impregnating a tropical wood with methyl-methacrylate and subsequent polymerization by γ-irradiation. Beam specimens both of untreated wood and polymer impregnated wood were subjected to a three-point bend creep test under a constant load of 300 N at 23 ± 1°C, at three different humidity levels of 50 ± 5, 65 ± 5 and 85 ± 5%. A Norton-Bailey (power law) mathematical model successfully described the creep behaviour, with the creep components determined by a non-linear regression analysis. A significant reduction in the sensitivity of creep deformation to the humidity level was attained for the polymer impregnated wood. This could be explained by the ability of the impregnated polymer to form a strongly adhesive interface with the wood cell material, thereby acting as a physical barrier to reduce the movement of water to and from the wood cell material.

  13. Leaching and antimicrobial properties of silver nanoparticles loaded onto natural zeolite clinoptilolite by ion exchange and wet impregnation

    CSIR Research Space (South Africa)

    Missengue, RNM


    Full Text Available This study aimed to compare the leaching and antimicrobial properties of silver that was loaded onto the natural zeolite clinoptilolite by ion exchange and wet impregnation. Silver ions were reduced using sodium borohydride (NaBH(sub4...

  14. A modified gold chloride technique for optimal impregnation of nerves within corneal whole mounts and dura of the albino rat. (United States)

    Silverberg, K R; Ogilvy, C S; Borges, L F


    Ranvier's method of staining tissue whole mounts with gold chloride to visualize nerve fibers was modified by lengthening the incubation time in gold chloride and reducing the time in acidulated water. These simple modifications of an old technique give consistent impregnation of nerve fibers with light background staining in whole mounts of cornea and dura.

  15. Carbon xerogels as catalyst supports for PEM fuel cell cathode

    Energy Technology Data Exchange (ETDEWEB)

    Job, Nathalie; Lambert, Stephanie [Laboratoire de Genie chimique, Universite de Liege, Institut de Chimie B6a, Sart-Tilman, B-4000 Liege (Belgium); Marie, Julien; Berthon-Fabry, Sandrine; Achard, Patrick [Ecole des Mines de Paris, Centre Energetique et Procedes, BP 207, F-06904 Sophia-Antipolis Cedex (France)


    Carbon xerogels with various pore textures were prepared by evaporative drying and pyrolysis of resorcinol-formaldehyde gels, and used as supports for Pt catalysts in PEM fuel cell cathodes. The goal of this study was to determine whether carbon xerogels could replace the carbon aerogels which were previously used as Pt catalyst supports in the same electrochemical system, and to determine how the pore texture influences the cell performances. Pt catalysts were prepared by impregnation of carbon supports with aqueous H{sub 2}PtCl{sub 6} solution followed by reduction in aqueous phase with NaBH{sub 4}. Fuel cell measurements show that the metal surface actually available for the oxygen reduction reaction and the voltage losses due to diffusion phenomena strongly depend on the carbon pore texture. Finally, some carbon xerogels yield similar performance than carbon aerogels. (author)

  16. Lightweight Ceramic Composition of Carbon Silicon Oxygen and Boron (United States)

    Leiser, Daniel B. (Inventor); Hsu, Ming-Ta (Inventor); Chen, Timothy S. (Inventor)


    Lightweight, monolithic ceramics resistant to oxidation in air at high temperatures are made by impregnating a porous carbon preform with a sol which contains a mixture of tetraethoxysilane, dimethyldiethoxysilane and trimethyl borate. The sol is gelled and dried on the carbon preform to form a ceramic precursor. The precursor is pyrolyzed in an inert atmosphere to form the ceramic which is made of carbon, silicon, oxygen and boron. The carbon of the preform reacts with the dried gel during the pyrolysis to form a component of the resulting ceramic. The ceramic is of the same size, shape and form as the carbon precursor. Thus, using a porous, fibrous carbon precursor, such as a carbon felt, results in a porous, fibrous ceramic. Ceramics of the invention are useful as lightweight tiles for a reentry spacecraft.

  17. Processing of thermo-structural carbon-fiber reinforced carbon composites

    Directory of Open Access Journals (Sweden)

    Luiz Cláudio Pardini


    Full Text Available The present work describes the processes used to obtain thermostructural Carbon/Carbon composites. The processing of these materials begins with the definition of the architecture of the carbon fiber reinforcement, in the form of stacked plies or in the form of fabrics or multidirectional reinforcement. Incorporating fiber reinforcement into the carbon matrix, by filling the voids and interstices, leads to the densification of the material and a continuous increase in density. There are two principal processing routes for obtaining these materials: liquid phase processing and gas phase processing. In both cases, thermal processes lead to the formation of a carbon matrix with specific properties related to their precursor. These processes also differ in terms of yield. With liquid phase impregnation the yield is around 45 per cent, while gas phase processing yields around 15 per cent.

  18. Adsorption of Carbon Dioxide, Ammonia, Formaldehyde, and Water Vapor on Regenerable Carbon Sorbents (United States)

    Wojtowicz, Marek A.; Cosgrove, Joseph E.; Serio, Michael A.; Wilburn, Monique


    Results are presented on the development of reversible sorbents for the combined carbon dioxide, moisture, and trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the long-term objective is to replace the above three modules with a single one. Furthermore, the current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is nonregenerable, and the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. In this study, several carbon sorbents were fabricated and tested for simultaneous carbon dioxide, ammonia, formaldehyde, and water sorption. Multiple adsorption/vacuum-regeneration cycles were demonstrated at room temperature, and also the enhancement of formaldehyde sorption by the presence of ammonia in the gas mixture.

  19. Catalytic flash pyrolysis of oil-impregnated-wood and jatropha cake using sodium based catalysts

    KAUST Repository

    Imran, Ali


    Catalytic pyrolysis of wood with impregnated vegetable oil was investigated and compared with catalytic pyrolysis of jatropha cake making use of sodium based catalysts to produce a high quality bio-oil. The catalytic pyrolysis was carried out in two modes: in-situ catalytic pyrolysis and post treatment of the pyrolysis vapors. The in-situ catalytic pyrolysis was carried out in an entrained flow reactor system using a premixed feedstock of Na2CO3 and biomass and post treatment of biomass pyrolysis vapor was conducted in a downstream fixed bed reactor of Na2CO3/γ-Al2O3. Results have shown that both Na2CO3 and Na2CO3/γ-Al2O3 can be used for the production of a high quality bio-oil from catalytic pyrolysis of oil-impregnated-wood and jatropha cake. The catalytic bio-oil had very low oxygen content, water content as low as 1wt.%, a neutral pH, and a high calorific value upto 41.8MJ/kg. The bio-oil consisted of high value chemical compounds mainly hydrocarbons and undesired compounds in the bio-oil were either completely removed or considerably reduced. Increasing the triglycerides content (vegetable oil) in the wood enhanced the formation of hydrocarbons in the bio-oil. Post treatment of the pyrolysis vapor over a fixed bed of Na2CO3/γ-Al2O3 produced superior quality bio-oil compared to in-situ catalytic pyrolysis with Na2CO3. This high quality bio-oil may be used as a precursor in a fractionating process for the production of alternative fuels. © 2015 Elsevier B.V.

  20. Silver-Impregnated Occlusive Dressing Reduces Rates of Acute Periprosthetic Joint Infection After Total Joint Arthroplasty. (United States)

    Grosso, Matthew J; Berg, Ari; LaRussa, Samuel; Murtaugh, Taylor; Trofa, David P; Geller, Jeffrey A


    Commercial silver-impregnated occlusive dressings (such as Aquacel Ag Surgical wound dressing) have been touted as antimicrobial dressings to be used following total joint arthroplasty. Given the increased cost of an Aquacel dressing over a standard dressing for total joint arthroplasty, the objective of this study was to determine whether Aquacel surgical dressing is effective in reducing the rates of acute periprosthetic joint infection (PJI) compared to standard sterile dressing. We retrospectively reviewed the charts of 1173 consecutive patients who underwent a total knee or total hip arthroplasty between 2007 and 2015 by 1 surgeon. The surgeon switched from using a standard xeroform/gauze dressing to an Aquacel dressing in June 2011, with no other major changes in antimicrobial management. Charts were reviewed for evidence of acute PJI (within 3 months of surgery). There were a total of 11 cases of acute PJI in this patient cohort (0.94%). The incidence of acute PJI for patients managed with a sterile xeroform dressing was 1.58% (9 of 568 patients), compared to 0.33% (2 of 605 patients) with the use of Aquacel dressing. Univariate analysis showed this to be statistically significant (P = .03), and a multiple logistic regression model supported Aquacel surgical dressing as a protective factor with an odds ratio of 0.092 (95% confidence interval, 0.017-0.490; P = .005). This 4-fold decrease in acute PJI with the use of Aquacel dressing supports the use of silver-impregnated occlusive dressings for the reduction of acute PJI. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Feasibility of coupling dehydration-impregnation by soaking treatment of meat with fermentation by Lactobacillus sakei. (United States)

    Bros, Manuela; Arnaud, Elodie; Loiseau, Gérard; Talon, Régine; Collignan, Antoine


    This study examined the feasibility of coupling dehydration-impregnation by soaking (DIS) with a subsequent lactic fermentation in the treatment of meat. A series of beef fillets were subjected to 3 different DIS treatments. The resulting DIS-treated fillets had 3 different characteristics in terms of water activity, salt, and fermentable sugars contents. Fillets treated with the DIS with the shortest immersion time (5 h) and the highest salt concentration in the DIS bath (100 g/L) were inoculated with Lactobacillus sakei. A control group was left without inoculation. After 24 h incubation at 25 °C, only inoculated fillets showed signs of lactic fermentation. At 24 h, these fillets had a d-lactic acid content of 68 μmol/g dry basis and a high population of L. sakei revealed by methods of plate count and quantitative PCR. DIS could therefore be compatible with a subsequent fermentation step by L. sakei. Traditional meat preservation processes often combine unit operations such as salting, smoking, fermentation, and drying. In tropical countries, high temperatures and high relative humidity, poor infrastructure, and improper slaughterhouse practices explain the need for more drastic processes (more salt, more water loss) for meat preservation. Dehydration-impregnation by soaking (DIS) could be used as a rapid pretreatment of meat, in order to counteract tropical conditions. This study validates a novel approach whereby DIS is coupled with lactic fermentation by surface inoculation with Lactobacillus sakei. With a final drying step this process could be used for the treatment of whole meat pieces. © 2012 Institute of Food Technologists®

  2. Acceptability of impregnated school uniforms for dengue control in Thailand: a mixed methods approach

    Directory of Open Access Journals (Sweden)

    Natasha Murray


    Full Text Available Background: As current dengue control strategies have been shown to be largely ineffective in reducing dengue in school-aged children, novel approaches towards dengue control need to be studied. Insecticide-impregnated school uniforms represent an innovative approach with the theoretical potential to reduce dengue infections in school children. Objectives: This study took place in the context of a randomised control trial (RCT to test the effectiveness of permethrin-impregnated school uniforms (ISUs for dengue prevention in Chachoengsao Province, Thailand. The objective was to assess the acceptability of ISUs among parents, teachers, and principals of school children involved in the trial. Methodology: Quantitative and qualitative tools were used in a mixed methods approach. Class-clustered randomised samples of school children enrolled in the RCT were selected and their parents completed 321 self-administered questionnaires. Descriptive statistics and logistic regression were used to analyse the quantitative data. Focus group discussions and individual semi-structured interviews were conducted with parents, teachers, and principals. Qualitative data analysis involved content analysis with coding and thematic development. Results: The knowledge and experience of dengue was substantial. The acceptability of ISUs was high. Parents (87.3%; 95% CI 82.9–90.8 would allow their child to wear an ISU and 59.9% (95% CI 53.7–65.9 of parents would incur additional costs for an ISU over a normal uniform. This was significantly associated with the total monthly income of a household and the educational level of the respondent. Parents (62.5%; 95% CI 56.6–68.1 indicated they would be willing to recommend ISUs to other parents. Conclusions: Acceptability of the novel tool of ISUs was high as defined by the lack of concern along with the willingness to pay and recommend. Considering issues of effectiveness and scalability, assessing acceptability of ISUs

  3. Efficient defluoridation of water using reusable nanocrystalline layered double hydroxides impregnated polystyrene anion exchanger. (United States)

    Cai, Jianguo; Zhang, Yanyang; Pan, Bingcai; Zhang, Weiming; Lv, Lu; Zhang, Quanxing


    Water decontamination from fluoride is still a challenging task of global concern. Recently, Al-based layered double hydroxides (LDHs) have been extensively studied for specific fluoride adsorption from water. Unfortunately, they cannot be readily applied in scaled-up application due to their ultrafine particles as well as the regeneration issues caused by their poor stability at alkaline pHs. Here, we developed a novel (LDH)-based hybrid adsorbent, i.e., LALDH-201, by impregnating nanocrystalline Li/Al LDHs (LADLH) inside a commercial polystyrene anion exchanger D201. TEM image and XRD spectra of the resultant nanocomposite confirmed that the LDHs particles were nanosized inside the pores of D201 of highly crystalline nature and well-ordered layer structure. After impregnation, the chemical and mechanical stability of LALDH were significantly improved against pH variation, facilitating its application at a wide pH range (3.5-12). Fluoride adsorption onto LALDH-201 was compared to D201 and activated alumina, evidencing the preferable removal fluoride of LALDH-201. Fluoride adsorption onto LALDH-201 followed pseudo-second-order model, with the maximum capacity (62.5 mg/g from the Sips model) much higher than the other two adsorbents. Fixed-bed adsorption run indicated the qualified treatable volume of the fluoride contaminated groundwater (4.1 mg/L initially) with LALDH-201 was about 11 times as much as with the anion exchanger D201 when the breakthrough point was set as 1.5 mg/L. The capacity of LALDH-201 could be effectively refreshed for continuous column operation without observable loss by using the mixed solution of 0.01 M NaOH + 1 M NaCl. The above results suggested that the hybrid adsorbent LALDH-201 is very promising for water defluoridation in scaled-up application. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. HZSM-5 Catalyst for Cracking Palm Oil to Gasoline: A Comparative Study with and without Impregnation

    Directory of Open Access Journals (Sweden)

    Achmad Roesyadi


    Full Text Available It is important to develop a renewable source of energy to overcome a limited source fossil energy. Palm oil is a potential alternative and environmental friendly energy resource in Indonesia due to high production capacity of this vegetable oil. The research studied effect of catalyst to selectivity of biofuel product from cracking of palm oil. The catalyst consisted of HZSM-5 catalyst with or without impregnation. The research was conducted in two steps, namely catalyst synthesized and catalytic cracking process. HZSM-5 was synthesized using Plank methods. The characterization of the synthesized catalysts used AAS (Atomic Absorption Spectroscopy and BET (Brunaueur Emmet Teller. The cracking was carried out in a fixed bed microreactor with diameter of 1 cm and length of 16 cm which was filled with 0.6 gram catalyst. The Zn/HZSM-5 catalyst was recommended for cracking palm oil for the high selectivity to gasoline. © 2013 BCREC UNDIP. All rights reserved.(Selected Paper from International Conference on Chemical and Material Engineering (ICCME 2012Received: 28th September 2012; Revised: 19th November 2012; Accepted: 20th December 2012[How to Cite: A. Roesyadi, D. Hariprajitno, N. Nurjannah, S.D. Savitri, (2013. HZSM-5 Catalyst for Cracking Palm Oil to Gasoline: A Comparative Study with and without Impregnation. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (3: 185-190.(doi:10.9767/bcrec.7.3.4045.185-190][Permalink/DOI: ] View in  |

  5. Acceptability of impregnated school uniforms for dengue control in Thailand: a mixed methods approach. (United States)

    Murray, Natasha; Jansarikij, Suphachai; Olanratmanee, Phanthip; Maskhao, Pongsri; Souares, Aurélia; Wilder-Smith, Annelies; Kittayapong, Pattamaporn; Louis, Valérie R


    As current dengue control strategies have been shown to be largely ineffective in reducing dengue in school-aged children, novel approaches towards dengue control need to be studied. Insecticide-impregnated school uniforms represent an innovative approach with the theoretical potential to reduce dengue infections in school children. This study took place in the context of a randomised control trial (RCT) to test the effectiveness of permethrin-impregnated school uniforms (ISUs) for dengue prevention in Chachoengsao Province, Thailand. The objective was to assess the acceptability of ISUs among parents, teachers, and principals of school children involved in the trial. Quantitative and qualitative tools were used in a mixed methods approach. Class-clustered randomised samples of school children enrolled in the RCT were selected and their parents completed 321 self-administered questionnaires. Descriptive statistics and logistic regression were used to analyse the quantitative data. Focus group discussions and individual semi-structured interviews were conducted with parents, teachers, and principals. Qualitative data analysis involved content analysis with coding and thematic development. The knowledge and experience of dengue was substantial. The acceptability of ISUs was high. Parents (87.3%; 95% CI 82.9-90.8) would allow their child to wear an ISU and 59.9% (95% CI 53.7-65.9) of parents would incur additional costs for an ISU over a normal uniform. This was significantly associated with the total monthly income of a household and the educational level of the respondent. Parents (62.5%; 95% CI 56.6-68.1) indicated they would be willing to recommend ISUs to other parents. Acceptability of the novel tool of ISUs was high as defined by the lack of concern along with the willingness to pay and recommend. Considering issues of effectiveness and scalability, assessing acceptability of ISUs over time is recommended.

  6. Efficacy of gentamycin-impregnated resorbable hydroxyapatite cement in treating osteomyelitis in a rat model. (United States)

    Solberg, B D; Gutow, A P; Baumgaertner, M R


    To test the effectiveness of a self-setting hydroxyapatite cement (HAC) as a carrier of gentamycin for the treatment of chronic osteomyelitis in a rat model by using a void-fill placement technique. Osteomyelitis of the tibia was created with Staphylococcus aureus (ATCC 49230) in sixty retired female breeder Sprague-Dawley rats by using the model by Korkusuz et al. (J Bone Joint Surg 1993;75B:111-114). At seven weeks after infection, all animals demonstrated clinical and radiographic signs of osteomyelitis and were debrided and divided into four treatment groups: A, debridement only; B, debridement and daily intraperitoneal gentamycin (0.2 milligram per kilogram per day); C, debridement and gentamycin-impregnated HAC in a void-fill model (1.0 milligram per kilogram of gentamycin); and D, debridement and gentamycin-impregnated polymethylmethacrylate (PMMA) beads (1.0 milligram per kilogram of gentamycin). Tibiae were harvested at zero weeks (control, n = 6), three weeks (n = 3 per group), five weeks (n = 4 per group), and seven weeks (n = 4 per group) and analyzed with quantitative bacteriologic analysis. Qualitative bacteriologic analysis was performed by using serial dilution plating of homogenized tissue samples on standard soy trypticase agar plates. Reexamination by phage typing was performed to exclude contamination. The quantitative counts for Groups C (HAC) and D (PMMA) were significantly less (p gentamycin) at all time points after time zero. There was no difference between Groups C and D at any time point. HAC is an effective adjuvant in treating chronic osteomyelitis in a rat model when using a void-fill placement technique.

  7. Stimulated myoblast differentiation on graphene oxide-impregnated PLGA-collagen hybrid fibre matrices. (United States)

    Shin, Yong Cheol; Lee, Jong Ho; Jin, Linhua; Kim, Min Jeong; Kim, Yong-Joo; Hyun, Jung Keun; Jung, Tae-Gon; Hong, Suck Won; Han, Dong-Wook


    Electrospinning is a simple and effective method for fabricating micro- and nanofiber matrices. Electrospun fibre matrices have numerous advantages for use as tissue engineering scaffolds, such as high surface area-to-volume ratio, mass production capability and structural similarity to the natural extracellular matrix (ECM). Therefore, electrospun matrices, which are composed of biocompatible polymers and various biomaterials, have been developed as biomimetic scaffolds for the tissue engineering applications. In particular, graphene oxide (GO) has recently been considered as a novel biomaterial for skeletal muscle regeneration because it can promote the growth and differentiation of myoblasts. Therefore, the aim of the present study was to fabricate the hybrid fibre matrices that stimulate myoblasts differentiation for skeletal muscle regeneration. Hybrid fibre matrices composed of poly(lactic-co-glycolic acid, PLGA) and collagen (Col) impregnated with GO (GO-PLGA-Col) were successfully fabricated using an electrospinning process. Our results indicated that the GO-PLGA-Col hybrid matrices were comprised of randomly-oriented continuous fibres with a three-dimensional non-woven porous structure. Compositional analysis showed that GO was dispersed uniformly throughout the GO-PLGA-Col matrices. In addition, the hydrophilicity of the fabricated matrices was significantly increased by blending with a small amount of Col and GO. The attachment and proliferation of the C2C12 skeletal myoblasts were significantly enhanced on the GO-PLGA-Col hybrid matrices. Furthermore, the GO-PLGA-Col matrices stimulated the myogenic differentiation of C2C12 skeletal myoblasts, which was enhanced further under the culture conditions of the differentiation media. Taking our findings into consideration, it is suggested that the GO-PLGA-Col hybrid fibre matrices can be exploited as potential biomimetic scaffolds for skeletal tissue engineering and regeneration because these GO-impregnated

  8. Simultaneous removal of ammonium and phosphate by alkaline-activated and lanthanum-impregnated zeolite. (United States)

    He, Yinhai; Lin, Hai; Dong, Yingbo; Liu, Quanli; Wang, Liang


    Simultaneous ammonium and phosphate removal characteristics and mechanism, as well as the major influencing factors, such as pH, temperature and co-existing ions, onto NaOH-activated and lanthanum-impregnated zeolite (NLZ) were investigated. The phosphate adsorption increases from 0.2 mg g-1 for natural zeolite up to 8.96 mg g-1 for NLZ, while only a slight decrease on the ammonium adsorption capacity from 23.9 mg g-1 for NaOH-activated zeolite to 21.2 mg g-1 for NLZ was observed. The ammonium and phosphate adsorption showed little pH dependence in the range from pH 3 to 7, while it decreased sharply with the pH increased above pH 7. Adsorption of ammonium and phosphate could be well described by the pseudo-second-order model and the process was mainly governed by intra-particle diffusion. The Langmuir and Freundlich model can be acceptably applied to fit the experimental data, which suggested that adsorption was caused by both the monolayer and homogeneous coverage at specific and equal affinity sites available NLZ. The underlying mechanism for the specific adsorption of phosphate by NLZ was revealed with the aid of SEM-EDS, XPS, and FTIR analysis, and the formation of (LaO)(OH)PO2 was verified to be the dominant pathway for selective phosphate adsorption by lanthanum-impregnated zeolite. While the removal mechanism of ammonium could be well interpreted by SEM-EDS, FTIR and ICP analysis, and ion-exchange was expected to be the main removal process for ammonium. The results indicate that NLZ could efficiently and simultaneously remove low concentration of ammonium and phosphate from contaminated waters. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. A comparative synthesis and physicochemical characterizations of Ni/Al2O3-MgO nanocatalyst via sequential impregnation and sol-gel methods used for CO2 reforming of methane. (United States)

    Aghamohammadi, Sogand; Haghighi, Mohammad; Karimipour, Samira


    Carbon dioxide reforming of methane is an interesting route for synthesis gas production especially over nano-sized catalysts. The present research deals with catalyst development for dry reforming of methane with the aim of reaching the most stable catalyst. Effect of preparation method, one of the most significant variables, on the properties of the catalysts was taken in to account. The Ni/Al2O3-MgO catalysts were prepared via sol-gel and sequential impregnation methods and characterized with XRD, FESEM, EDAX, BET and FTIR techniques. The reforming reactions were carried out using different feed ratios, gas hourly space velocities (GHSV) and reaction temperatures to identify the influence of operational variables. FESEM images indicate uniform particle size distribution for the sample synthesized with sol-gel method. It has been found that the sol-gel method has the potential to improve catalyst desired properties especially metal surface enrichment resulting in catalytic performance enhancement. The highest yield of products was obtained at 850 degrees C for both of the catalysts. During the 10 h stability test, CH4 and CO2 conversions gained higher values in the case of sol-gel made catalyst compared to impregnated one.

  10. Benzene Removal by Iron Oxide Nanoparticles Decorated Carbon Nanotubes

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    Aamir Abbas


    Full Text Available In this paper, carbon nanotubes (CNTs impregnated with iron oxide nanoparticles were employed for the removal of benzene from water. The adsorbents were characterized using scanning electron microscope, X-ray diffraction, BET surface area, and thermogravimetric analysis. Batch adsorption experiments were carried out to study the adsorptive removal of benzene and the effect of parameters such as pH, contact time, and adsorbent dosage. The maximum removal of benzene was 61% with iron oxide impregnated CNTs at an adsorbent dosage 100 mg, shaking speed 200 rpm, contact time 2 hours, initial concentration 1 ppm, and pH 6. However, raw CNTs showed only 53% removal under same experimental conditions. Pseudo-first-order kinetic model was found well to describe the obtained data on benzene removal from water. Initial concentration was varied from 1 to 200 mg/L for isotherms study. Langmuir isotherm model was observed to best describe the adsorption data. The maximum adsorption capacities were 987.58 mg/g and 517.27 mg/g for iron oxide impregnated CNTs and raw CNTs, respectively. Experimental results revealed that impregnation with iron oxide nanoparticles significantly increased the removal efficiency of CNTs.

  11. Carbon-based air electrodes carrying MnO 2 in zinc-air batteries (United States)

    Wei, Zidong; Huang, Wenzhang; Zhang, Shengtao; Tan, Jun

    Catalysts prepared from the carbon black impregnated with manganous nitrate solution and then heated at temperature from 270°C to 450°C were investigated. It was found that the impregnated catalysts heated at temperature of 340°C exhibited the best catalytic activity for oxygen reduction in alkaline electrolyte. It was also found that the XRD spectra of pyrolytic MnO 2 from manganous nitrate over 340°C were different from those below 340°C. The enhanced catalysis of air electrodes was ascribed to the formation of MnO 2 crystal with d-value of 2.72 Å as the impregnated-catalysts was heated at temperature of 340°C. The other factors in preparation of air electrodes were also discussed.

  12. Pelletization of catalysts supported on activated carbon. A Case Study : clean synthesis of dimethyl carbonate from methanol and CO2


    Orrego Romero, Andrés Felipe; Arbeláez Pérez, Oscar Felipe; Bustamante Londoño, Felipe; Villa Holguín, Aída Luz


    The synthesis of Cu-Ni bimetallic catalyst supported on pellets of activated carbon using carboxymethylcellulose (CMC) as a binder is reported. The effect of preparation conditions, such as binder concentration, AC/binder ratio, temperature, and pyrolysis heating rate on the surface area of the pellets, was evaluated. Cu and Ni metals were incorporated on the pellets by conventional incipient wetness impregnation. The support and the synthesized catalysts were characterized using N2 adsorptio...

  13. Design of Pt/Carbon Xerogel Catalysts for PEM Fuel Cells

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    Nathalie Job


    Full Text Available The design of efficient catalytic layers of proton exchange membrane fuel cells (PEMFCs requires the preparation of highly-loaded and highly-dispersed Pt/C catalysts. During the last few years, our work focused on the preparation of Pt/carbon xerogel electrocatalysts, starting from simple impregnation techniques that were further optimized via the strong electrostatic adsorption (SEA method to reach high dispersion and a high metal weight fraction. The SEA method, which consists of the optimization of the precursor/support electrostatic impregnation through an adequate choice of the impregnation pH with regard to the support surface chemistry, leads to very well-dispersed Pt/C samples with a maximum 8 wt.% Pt after drying and reduction under H2. To increase the metal loading, the impregnation-drying-reduction cycle of the SEA method can be repeated several times, either with fresh Pt precursor solution or with the solution recycled from the previous cycle. In each case, a high dispersion (Pt particle size ~3 nm is obtained. Finally, the procedure can be simplified by combination of the SEA technique with dry impregnation, leading to no Pt loss during the procedure.

  14. Importance of post-translational modifications for functionality of a chloroplast-localized carbonic anhydrase (CAH1 in Arabidopsis thaliana.

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    Stefan Burén

    Full Text Available BACKGROUND: The Arabidopsis CAH1 alpha-type carbonic anhydrase is one of the few plant proteins known to be targeted to the chloroplast through the secretory pathway. CAH1 is post-translationally modified at several residues by the attachment of N-glycans, resulting in a mature protein harbouring complex-type glycans. The reason of why trafficking through this non-canonical pathway is beneficial for certain chloroplast resident proteins is not yet known. Therefore, to elucidate the significance of glycosylation in trafficking and the effect of glycosylation on the stability and function of the protein, epitope-labelled wild type and mutated versions of CAH1 were expressed in plant cells. METHODOLOGY/PRINCIPAL FINDINGS: Transient expression of mutant CAH1 with disrupted glycosylation sites showed that the protein harbours four, or in certain cases five, N-glycans. While the wild type protein trafficked through the secretory pathway to the chloroplast, the non-glycosylated protein formed aggregates and associated with the ER chaperone BiP, indicating that glycosylation of CAH1 facilitates folding and ER-export. Using cysteine mutants we also assessed the role of disulphide bridge formation in the folding and stability of CAH1. We found that a disulphide bridge between cysteines at positions 27 and 191 in the mature protein was required for correct folding of the protein. Using a mass spectrometric approach we were able to measure the enzymatic activity of CAH1 protein. Under circumstances where protein N-glycosylation is blocked in vivo, the activity of CAH1 is completely inhibited. CONCLUSIONS/SIGNIFICANCE: We show for the first time the importance of post-translational modifications such as N-glycosylation and intramolecular disulphide bridge formation in folding and trafficking of a protein from the secretory pathway to the chloroplast in higher plants. Requirements for these post-translational modifications for a fully functional native

  15. Enhanced photocatalytic activity of TiO2-impregnated with MgZnAl mixed oxides obtained from layered double hydroxides for phenol degradation (United States)

    de Almeida, Marciano Fabiano; Bellato, Carlos Roberto; Mounteer, Ann Honor; Ferreira, Sukarno Olavo; Milagres, Jaderson Lopes; Miranda, Liany Divina Lima


    A series of TiO2/MgZnAl photocatalysts were successfully synthesized from ternary (Mg, Zn and Al) layered double hydroxides impregnated with TiO2 nanoparticles by the co-precipitation method at variable pH with different Zn2+/Mg2+ molar ratios. The composite photocatalysts were calcined at 500 °C resulting in the incorporation of oxide zinc, in the calcined MgZnAl LDH structure. Synergistic effect between ZnO and TiO2 lead to significant enhancement of TiO2/MgZnAl photocatalytic activity. Composite photocatalysts were characterized by ICP-MS, N2 adsorption-desorption, XRD, SEM, EDS, IR and UV-vis DRS. Phenol in aqueous solution (50 mg/L) was used as a model compound for evaluation of UV-vis (filter cut-off for λ > 300 nm) photocatalytic activity. The most efficient photocatalyst composite was obtained at a 5% Zn2+/Mg2+ molar ratio, in the catalyst identified as TiO2/MgZnAl-5. This composite catalyst had high photocatalytic activity, completely destroying phenol and removing 80% of total organic carbon in solution after 360 min. The TiO2/MgZnAl-5 catalyst remained relatively stable, presenting a 15% decrease in phenol degradation efficiency after five consecutive photocatalytic cycles.

  16. CATheter Infections in CHildren (CATCH): a randomised controlled trial and economic evaluation comparing impregnated and standard central venous catheters in children. (United States)

    Harron, Katie; Mok, Quen; Dwan, Kerry; Ridyard, Colin H; Moitt, Tracy; Millar, Michael; Ramnarayan, Padmanabhan; Tibby, Shane M; Muller-Pebody, Berit; Hughes, Dyfrig A; Gamble, Carrol; Gilbert, Ruth E


    Impregnated central venous catheters (CVCs) are recommended for adults to reduce bloodstream infection (BSI) but not for children. To determine the effectiveness of impregnated compared with standard CVCs for reducing BSI in children admitted for intensive care. Multicentre randomised controlled trial, cost-effectiveness analysis from a NHS perspective and a generalisability analysis and cost impact analysis. 14 English paediatric intensive care units (PICUs) in England. Children aged managing BSIs in PICUs with standard BSI rates of > 1.2 per 1000 CVC-days. The primary outcome did not differ between impregnated and standard CVCs. However, antibiotic-impregnated CVCs significantly reduced the risk of BSI compared with standard and heparin CVCs. Adoption of antibiotic-impregnated CVCs could be beneficial even for PICUs with low BSI rates, although uncertainty remains whether or not they represent value for money to the NHS. Limitations - inserting clinicians were not blinded to allocation and a lower than expected event rate meant that there was limited power for head-to-head comparisons of each type of impregnation. Future work - adoption of impregnated CVCs in PICUs should be considered and could be monitored through linkage of electronic health-care data and clinical data on CVC use with laboratory surveillance data on BSI. NCT01029717. This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 18. See the NIHR Journals Library website for further project information.

  17. Ultrasonic impregnation of MnO2/CeO2and its application in catalytic sono-degradation of methyl orange. (United States)

    Zhang, Nan; Zhang, Guangming; Chong, Shan; Zhao, He; Huang, Ting; Zhu, Jia


    MnO 2 /CeO 2 catalyst was prepared by ultrasonic impregnation method. The traditional and stirring impregnation methods were used as control. Results showed that ultrasonic impregnation was the best synthesis method. The impregnation time was shortened from 120 min (traditional method) to 20 min, the specific surface area of catalyst was three times larger, and the catalytic activity of catalyst was also the highest. Furthermore, MnO 2 had crystalline structure and distributed uniformly on the support, CeO 2 . The preparing conditions were further examined and the optimal conditions were found to be: 20 min of ultrasonic impregnation, 4.3 mol/L of manganese nitrate concentration and 450 °C of calcination temperature. The so prepared catalyst removed 94% of methyl orange in 30 min with a dosage of 0.5 g/L. The efficiency was 77.7% and 85.9% for traditional and stirring impregnation method under the same experimental conditions. The reaction process involved two stages: adsorption-dominated and degradation-dominated stages. The reaction rate constant of adsorption-dominated stage had little difference. However, compared with traditional impregnation, the reaction rate constant of degradation-dominated stage improved from 0.01 to 0.14 min -1 by ultrasonic impregnation. Mechanism analysis showed that the activity of ultrasonic impregnation MnO 2 /CeO 2 was improved by the effects of acoustic cavitation and ultrasound oscillation on solid-liquid transport and distribution status. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. A quantitative electron tomography study of ruthenium particles on the interior and exterior surfaces of carbon nanotubes

    NARCIS (Netherlands)

    Friedrich, H.|info:eu-repo/dai/nl/304837350; Guo, S.; de Jongh, P.E.|info:eu-repo/dai/nl/186125372; Pan, X.; Bao, X.|info:eu-repo/dai/nl/371576679; de Jong, K.P.|info:eu-repo/dai/nl/06885580X


    The efficiency of filling carbon nanotubes (CNTs) by ultrasound-assisted wet impregnation is quantified by electron tomography (ET). For image analysis, a method that combines edge detection with single-value thresholding is proposed and validated. A high proportion (80 wt %) of the ruthenium was

  19. Production of activated carbon from a new precursor: Molasses (United States)

    Legrouri, K.; Ezzine, M.; Ichcho, S.; Hannache, H.; Denoyel, R.; Pailler, R.; Naslain, R.


    Activated carbon has been prepared from molasses, a natural precursor of vegetable origin resulting from the sugar industry in Morocco. The preparation of the activated carbon from the molasses has been carried out by impregnation of the precursor with sulfuric acid, followed by carbonization. The adsorption capacity, the BET surface area, and the pore volume of the activated carbon were determined. The micropore volume was assessed by Dubinin- Radushkevich (DR) equation. The activated materials are mainly microporous and show the type I isotherm of the Brunauer classification for nitrogen adsorption. The activation in steam yielded a carbon that contains both micropores and supermicropores. Analysis of the nitrogen isotherm by BET and DR methods established that most of obtained carbons are highly microporous, with high surface areas (≥ 1200 m2/g) and very low mesoporosity.

  20. Electron-beam-initiated polymerization of poly(ethylene glycol)-based wood impregnants. (United States)

    Trey, Stacy M; Netrval, Julia; Berglund, Lars; Johansson, Mats


    The current study demonstrates that methacrylate and acrylate poly(ethylene glycol) (PEG) functional oligomers can be effectively impregnated into wood blocks, and cured efficiently to high conversions without catalyst by e-beam radiation, allowing for less susceptibility to leaching, and favorable properties including higher Brinell hardness values. PEG based monomers were chosen because there is a long history of this water-soluble monomer being able to penetrate the cell wall, thus bulking it and decreasing the uptake of water which further protects the wood from fungal attack. Diacrylate, dimethacrylate, and dihydroxyl functional PEG of M(w) 550-575, of concentrations 0, 30, 60, and 100 wt % in water, were vacuum pressure impregnated into Scots Pine blocks of 15 × 25 × 50 mm in an effort to bulk the cell wall. The samples were then irradiated and compared with nonirradiated samples. It was shown by IR, DSC that the acrylate polymers were fully cured to much higher conversions than can be reached with conventional methods. Leaching studies indicated a much lower amount of oligomer loss from the cured vinyl functional PEG chains in comparison to hydroxyl functional PEG indicating a high degree of fastening of the polymer in the wood. The Brinell hardness indicated a significant increase in hardness to hardwood levels in the modified samples compared to the samples of hydroxyl functional PEG and uncured vinyl PEG samples, which actually became softer than the untreated Scots Pine. By monitoring the dimensions of the sample it was found by weight percent gain calculations (WPG %) that water helps to swell the wood structure and allow better access of the oligomers into the cell wall. Further, the cure shrinkage of the wood samples demonstrated infiltration of the oligomers into the cell wall as this was not observed for methyl methacrylate which is well-documented to remain in the lumen. However, dimensional stability of the vinyl polymer modified blocks when

  1. Sustaining Phenolic Impregnated Carbon Ablator (PICA) for Future NASA Robotic Science Missions Including NF-4 and Discovery (United States)

    Venkatapathy, E.; Stackpoole, M.; Violette, S.


    Sustainability of PICA for the upcoming NF-4 and future Discovery to Flag missions required us to evaluate new source of domestic rayon as the current rayon supplier has discontinued manufacturing. This poster presents results from our investigation.

  2. Wood-polymer composite: physical and mechanical properties of some wood species impregnated with styrene and methyl methacrylate

    Directory of Open Access Journals (Sweden)

    Denise Ortigosa Stolf


    Full Text Available This study aimed to demonstrate the feasibility of obtaining wood-polymer composites (WPC displaying a performance superior to that of untreated wood from reforested genera. To this end, wood samples of Pine (Pinus caribaea and Eucalyptus (Eucalyptus grandis, whose density is compatible with this process, were impregnated with the polymeric monomers styrene and methyl methacrylate, using benzoyl peroxide to initiate the polymerization process forming free radicals. The vacuum-pressure method was used to impregnate the samples with monomer-initiator solution. The results indicated a significant improvement of all the properties investigated, including dimensional stability, for the Pine-WPC, while Eucalyptus-WPC, owing to the wood's low permeability, showed only increased values of hardness parallel and perpendicular to grain.

  3. Supercritical impregnation of polymer matrices spatially confined in microcontainers for oral drug delivery: Effect of temperature, pressure and time

    DEFF Research Database (Denmark)

    Marizza, Paolo; Pontoni, L.; Rindzevicius, Tomas


    The present study is aimed to enhance the oral bioavailability of ketoprofen by inserting it into the matrixof poly(vinylpyrrolidone) (PVP) K10 spatially confined into microcontainers, by means of supercriticalCO2-aided impregnation. Microcontainers are cylindrical reservoirs, with typical sizes...... sol-ubility in water. In a previous study we introduced a novel technique for drug loading of microcontainers,based on inkjet printing and supercritical impregnation (SCI). We showed that SCI produces accurate andreproducible drug loading for large arrays of microcontainers. In the attempt...... parameters(temperature, pressure, time, drug concentration in the supercritical phase) was elucidated with respectto the loading capacity. The microcontainer filling was observed by means of optical macroimaging, X-ray microtomography and scanning electron microscopy. The physical state of the drug...

  4. Can Teicoplanin Be an Effective Choice for Antibiotic-Impregnated Cement Spacer in Two-Stage Revision Total Knee Arthroplasty? (United States)

    Buyuk, Abdul Fettah; Sofu, Hakan; Camurcu, Ismet Yalkin; Ucpunar, Hanifi; Kaygusuz, Mehmet Akif; Sahin, Vedat


    The main purpose of this study was to evaluate the clinical results of two-stage revision total knee arthroplasty using a teicoplanin-impregnated cement spacer for infected primary total knee replacements. Twenty-five patients operated between 2005 and 2012 were included in this study. At the clinical status analysis, rate of infection eradication was assessed, physical examination was performed, Knee Society Score (KSS) was noted, isolated microorganisms were recorded, and the radiographic evaluation was performed. The mean KSS improved from 40 (range, 25-69) preoperatively to 77 (range, 32-96) at the latest follow-up (p Teicoplanin was found to be an effective choice for antibiotic-impregnated cement spacer applied for the eradication of the infection. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  5. Achieving Amphibious Superprotonic Conductivity in a CuI Metal-Organic Framework by Strategic Pyrazinium Salt Impregnation. (United States)

    Khatua, Sajal; Bar, Arun Kumar; Sheikh, Javeed Ahmad; Clearfield, Abraham; Konar, Sanjit


    Treatment of a pyrazine (pz)-impregnated CuI metal-organic framework (MOF) ([1⊃pz]) with HCl vapor renders an interstitial pyrazinium chloride salt-hybridized MOF ([1⊃pz⋅6 HCl]) that exhibits proton conductivity over 10-2  S cm-1 both in anhydrous and under humid conditions. Framework [1⊃pz⋅6 HCl] features the highest anhydrous proton conductivity among the lesser-known examples of MOF-based materials exhibiting proton conductivity under both anhydrous and humid conditions. Moreover, [1⊃pz] and corresponding pyrazinium sulfate- and pyrazinium phosphate-hybridized MOFs also exhibit superprotonic conductivity over 10-2  S cm-1 under humid conditions. The impregnated pyrazinium ions play a crucial role in protonic conductivity, which occurs through a Grotthuss mechanism. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. [Resolution of clenbuterol hydrochloride enantiomers by thin-layer chromatography on silica gel impregnated with beta-cyclodextrin]. (United States)

    Yu, Jingang; Huang, Kelong; Jiao, Feipeng; Peng, Xiahui


    The resolution of clenbuterol hydrochloride enantiomers was achieved by thin-layer chromatography on silica gel GF254 plates impregnated w ith beta-cyclodextrin. The effect of stereoselective auxiliary (acetonitrile and alcohol) was investigated. Resolution of clenbuterol hydrochloride enantiomers could be attained by using alcohols of butanol, 2-butanol or tert-butanol together with acetonitrile as developing solvent. The optimal conditions of resolution were determined as follows: a plate prepared with 15.00 g silica gel GF254 impregnated with 1.00 g beta-cyclodextrin, acetonitrile-2-butanol (20:80, v/v) as developing solvent and developed at room temperature. Under these conditions, Rf of the two isomers of clenbuterol hydrochloride enantiomers were 0.34 and 0.72 respectively. The resolution was 4.09 with baseline separation and the spots in chromatogram were almost of the same size.

  7. Selective disruption of disulphide bonds lowered activation energy and improved catalytic efficiency in TALipB from Trichosporon asahii MSR54: MD simulations revealed flexible lid and extended substrate binding area in the mutant. (United States)

    Singh, Yogesh; Gupta, Namita; Verma, Ved Vrat; Goel, Manisha; Gupta, Rani


    TALipB (33 kDa) is a solvent stable, enantioselective lipase from Trichosporon asahii MSR54. It is cysteine-rich and shows activation in presence of thiol reducing agents. DIANNA server predicted three disulphide bridges C53-C195 (S1), C89-C228 (S2) and C164-C254 (S3) in the enzyme. Selective disruption of disulphide bonds by cysteine to alanine mutations at Cys53 and Cys89 of S1 and S2 bonds resulted in enzyme activation. Mutant mTALipB (S1+S2) showed increase in specific activity by ∼4-fold (834 mM/mg) and improved Vmax of 6.27 μmol/ml/min at 40 °Con pNP caprate. Temperature optima of mTALipB shifted from 50 to 40 °C and activation energy decreased by 0.7 kcal mol(-1). However, the mutant was less thermostable with a t1/2 of 18 min at 60 °C as compared to t1/2 of 38 min for the native enzyme. Mutant also displayed an improved activity on all pNP esters and higher enantiomeric excess (61%) during esterification of (±) 1-phenylethanol. Far-UV CD analysis showed significant changes in secondary structure after S-S bridge disruption with 7.16% decrease in α-helices and 1.31% increase in β-sheets. In silico analysis predicted two lids (α5 and α9) in TALipB. Molecular dynamic simulations at 40 °C and 50 °C revealed that in the mTALipB, both the lids opened at 40 °C with clockwise and anticlockwise rotations in Lid1 and Lid2, respectively. In the native protein, however, the lid was only partially open even at 50 °C. Concomitant to lid flexibility, there was an extension of accessible catalytic triad surface area resulting in improved catalytic efficiency of the mutant enzyme. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Mechanical and Thermal Properties of Epoxy Composites Containing Zirconium Oxide Impregnated Halloysite Nanotubes

    Directory of Open Access Journals (Sweden)

    Moon il Kim


    Full Text Available Liquid epoxy resins have received much attention from both academia and the chemical industry as eco-friendly volatile organic compound (VOC-free alternatives for applications in coatings and adhesives, especially in those used in households. Epoxy resins show high chemical resistance and high creep resistance. However, due to their brittleness and lack of thermal stability, additional fillers are needed for improving the mechanical and thermal properties. Halloysite nanotubes (HNTs are naturally abundant, inexpensive, and eco-friendly clay minerals that are known to improve the mechanical and thermal properties of epoxy composites after suitable surface modification. Zirconium is well known for its high resistance to heat and wear. In this work, zirconium oxide-impregnated HNTs (Zr/HNTs were added to epoxy resins to obtain epoxy composites with improved mechanical and thermal properties. Zr/HNTs were characterized by field-emission transmission electron microscopy, transmission electron microscopy with energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Changes in the thermal properties of the epoxy composites were characterized by thermo mechanical analysis and differential scanning calorimetry. Furthermore, flexural properties of the composites were analyzed using a universal testing machine.

  9. An Improved Impregnated-filter Method for Measuring Low-levelConcentrations of Toluene

    Energy Technology Data Exchange (ETDEWEB)

    Mahanama, K.R.R.; Hodgson, A.T.


    An improved method was developed and validated for measuring low-level concentrations of toluene diisocyanates (TDls) in air. The method is based on OSHA Method 42 for industrial applications. Airborne TDls were trapped on a 25-mm glass-fiber filter impregnated with 50 pg of 1-(2-pyridy1)piperazine. A filter holder was constructed to minimize contamination and losses of the analytes. The derivatized TDls were extracted by immersion of the filter in a small volume of solvent. The analysis was performed with a high performance liquid chromatograph equipped with a fluorescence detector and a CIB base-deactivated silica column. The modified method has a lower limit of quantitation of 0.02 ppb in 15 L of air for both 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI), which is about a fifteen-fold enhancement over Method 42. The recovery efficiencies and 95% confidence intervals for vapor-spiked filters were 77 {+-} 6 percent for 2,4-TDI and 69 {+-} 10 percent for 2,6-TDI. The precision of replicate analyses was ten percent or better. The method was used to screen flexible polyurethane foam for emissions of unreacted TDls.

  10. Product analysis of partial discharge damage to oil-impregnated insulation paper (United States)

    Yan, Jiaming; Liao, Ruijin; Yang, Lijun; Li, Jian; Liu, Bin


    Surface products of oil-impregnated insulation paper during the damage process caused by partial discharge (PD), as well as gas within the cavity, were studied. An optical microscope and a scanning electron microscope (SEM) were used to investigate surface morphology, while an infrared spectroscopy (IR) and an X-ray photoelectron spectroscopy (XPS) were used to study surface products and their components. The volume variation in cavity gas was also analyzed. Furthermore, gas constituents and their relevant contents were studied using a gas chromatography-mass spectrometer (GC-MS). The study results reveal the following: during the PD damage process, the total gas volume and the content of electronegative gasses alternately decline and increase, while discharge types alternate between pulse type and pseudo-glow type (or glow type); “surface droplets” and “crystalline solids” appear on the insulation surface one after another; surface droplets mainly consist of (Cdbnd O)-group-containing compounds, whereas crystalline solids are mainly carboxylic acids, with carboxyl groups also found in cellulose chains; and the discharge type related to the oxidization of decomposition products is the main factor that determines the state (liquid or solid) of the surface products.

  11. Quantum dot impregnated-chitosan film for heavy metal ion sensing and removal. (United States)

    Jaiswal, Amit; Ghsoh, Siddhartha Sankar; Chattopadhyay, Arun


    We report the use of biopolymer-stabilized ZnS quantum dots (Q-dots) for cation exchange reaction-based easy sensing and removal of heavy metal ions such as Hg(2+), Ag(+), and Pb(2+) in water. Chitosan-stabilized ZnS Q-dots were synthesized in aqueous medium and were observed to have been converted to HgS, Ag(2)S, and PbS Q-dots in the presence of corresponding ions. The transformed Q-dots showed characteristic color development, with Hg(2+) being exceptionally identifiable due to the visible bright yellow color formation, while brown coloration was observed in other metal ions. The cation exchange was driven by the difference in the solubility product of the reactant and the product Q-dots. The cation exchanged Q-dots preserved the morphology of the reactant Q-dots and displayed volume increase based on the bulk crystal lattice parameters. The band gap of the transformed Q-dots showed a major increase from the corresponding bulk band gap of the material, demonstrating the role of quantum confinement. Next, we fabricated ZnS Q-dot impregnated chitosan film which was used to remove heavy metal ions from contaminated water as measured using atomic absorption spectroscopy (AAS). The present system could suitably be used as a simple dipstick for elimination of heavy metal ion contamination in water.

  12. Thermal conductivity of bulk boron nitride nanotube sheets and their epoxy-impregnated composites

    Energy Technology Data Exchange (ETDEWEB)

    Jakubinek, Michael B.; Kim, Keun Su; Simard, Benoit [Security and Disruptive Technologies, Division of Emerging Technologies, National Research Council Canada, Ottawa, ON (Canada); Niven, John F. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS (Canada); Johnson, Michel B. [Institute for Research in Materials, Dalhousie University, Halifax, NS (Canada); Ashrafi, Behnam [Aerospace, Division of Engineering, National Research Council Canada, Montreal, QC (Canada); White, Mary Anne [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS (Canada); Institute for Research in Materials, Dalhousie University, Halifax, NS (Canada); Department of Chemistry, Dalhousie University, Halifax, NS (Canada)


    The thermal conductivity of bulk, self-supporting boron nitride nanotube (BNNT) sheets composed of nominally 100% BNNTs oriented randomly in-plane was measured by a steady-state, parallel thermal conductance method. The sheets were either collected directly during synthesis or produced by dispersion and filtration. Differences between the effective thermal conductivities of filtration-produced BNNT buckypaper (∝1.5 W m{sup -1} K{sup -1}) and lower-density as-synthesized sheets (∝0.75 W m{sup -1} K{sup -1}), which are both porous materials, were primarily due to their density. The measured results indicate similar thermal conductivity, in the range of 7-12 W m{sup -1} K{sup -1}, for the BNNT network in these sheets. High BNNT-content composites (∝30 wt.% BNNTs) produced by epoxy impregnation of the porous BNNT network gave 2-3 W m{sup -1} K{sup -1}, more than 10 x the baseline epoxy. The combination of manufacturability, thermal conductivity, and electrical insulation offers exciting potential for electrically insulating, thermally conductive coatings and packaging. Thermal conductivity of free-standing BNNT buckypaper, buckypaper composites, and related materials at room temperature. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. In vitro biocompatibility tests of glass ionomer cements impregnated with collagen or bioactive glass to fibroblasts. (United States)

    Subbarao, C; Neelakantan, P; Subbarao, C V


    To evaluate the biocompatibility of glass ionomer cement (GIC) impregnated with collagen or bioactive glass to BHK-21 fibroblasts in vitro. Mineral Trioxide Aggregate was used as the standard for comparison. Human maxillary central incisors (n = 70) were instrumented with a rotary NiTi system and filled. Following resection of the apical 3mm, root end cavities were prepared and restored with conventional GIC (group 1) or GIC with 0.01%, 0.1% or 1% collagen (groups 2, 3, 4 respectively) or, 10%, 30% or 50% bioactive glass (groups 5, 6, 7 respectively), or Mineral Trioxide Aggregate (group 8). The root slices were incubated in tissue culture plates with BHK-21 fibroblast cell line. Phase contrast and scanning electron microscopes were used to score cell quantity, morphology and cell attachment. The data were statistically analyzed by one way ANOVA with Post Hoc Tukey HSD test (p = 0.05). Group 5 showed the highest scores which was significantly higher than all other groups (p 0.05). Glass ionomer cement with 10% bioactive glass showed better adhesion and spreading of cells than glass ionomer cement with 0.01% collagen. The biocompatibility of collagen and bioactive glass was concentration dependent. The addition of bioactive glass improved the biocompatibility of glass ionomer cement to fibroblasts better than addition of collagen.

  14. Preparation, characterization and evaluation of biocomposite films containing chitosan and sago starch impregnated with silver nanoparticles. (United States)

    Arockianathan, P Marie; Sekar, S; Kumaran, B; Sastry, T P


    The positive attributes of excellent biocompatibility and biodegradability of biopolymers with versatile biological activities have provided ample opportunities for further development of functional biomaterials of high potential in various fields. The biopolymers used in this study, i.e. chitosan and sago starch are abundantly available in nature and can be used in various biomedical applications. In the present study, the composite films of chitosan (Ch) and sago starch (SG) impregnated with silver nanoparticles (AgNP) with and without antibiotic gentamicin (G) were prepared by solvent casting method. The films prepared were characterized for their physic-chemical properties using conventional methods. The results obtained showed that with the increase of chitosan content in the composite results in decrease in its water absorption capacity. The FTIR and SEM studies have shown the composite nature of the films prepared. Ch-SG-AgNP and Ch-SG-AgNP-G composites were used as wound dressing materials in experimental wounds of rats. The healing pattern of the wounds was evaluated by planimetric studies, macroscopic observations, biochemical studies and histopathological observations. The results have shown faster healing pattern in the wounds treated with Ch-SG-AgNP and Ch-SG-AgNP-G composites compared to untreated control. This study suggests that Ch-SG-AgNP film may be a potential candidate as a dressing material for wound healing applications. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Effect of drying conditions on the physical properties of impregnated orange peel

    Directory of Open Access Journals (Sweden)

    K. Manjarres-Pinzon


    Full Text Available Orange peel represents approximately 30-40 g/100g of the fresh fruit weight and could be used to develop value-added products. Hence, this study aims to evaluate the effects of drying conditions on the physical properties of orange peel impregnated with sucrose solution. The response surface method (RSM was used to optimize two parameters: drying temperature (35-55 ºC and air flow rate (2-3 m/s. The measured responses used to determine the effect of dying process conditions were: moisture content. drying time. total soluble solids. color and hardness. The dried orange peels from the optimal process were subjected to a sensory test by 60 consumers. The optimum conditions for the drying of orange peels were determined to obtain minimum hardness, moisture content and drying time for a w values below 0.6. The optimum conditions were found to be a dying temperature of 52.3 ºC and air flow rate of 2.0 m/s. At this point, drying time, hardness and moisture content were found to be 20 h, 78.4 N and 7.6%, respectively. The sensory results showed that consumers aged over 30 years old accepted well the dried orange peel.

  16. Removal of heavy metals in wastewater by using zeolite nano-particles impregnated polysulfone membranes. (United States)

    Yurekli, Yilmaz


    In this study, the adsorption and the filtration processes were coupled by a zeolite nanoparticle impregnated polysulfone (PSf) membrane which was used to remove the lead and the nickel cations from synthetically prepared solutions. The results obtained from X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis indicated that the synthesized zeolite nanoparticles, using conventional hydrothermal method, produced a pure NaX with ultrafine and uniform particles. The performance of the hybrid membrane was determined under dynamic conditions. The results also revealed that the sorption capacity as well as the water hydraulic permeability of the membranes could both be improved by simply tuning the membrane fabricating conditions such as evaporation period of the casting film and NaX loading. The maximum sorption capacity of the hybrid membrane for the lead and nickel ions was measured as 682 and 122 mg/g respectively at the end of 60 min of filtration, under 1 bar of transmembrane pressure. The coupling process suggested that the membrane architecture could be efficiently used for treating metal solutions with low concentrations and transmembrane pressures. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Indicator-Impregnated Agarose Films for Colorimetric Measurement of pH. (United States)

    Pathak, Abhishek; Borana, Jayant; Adhikari, Jayesh Vasudeva; Gorthi, Sai Siva


    In this article, we report on the development of indicator-impregnated agarose sensor films for colorimetric estimation of the pH of different standard buffer solutions and urine samples. In contrast to the conventional paper-based dipstick method, the presented method employs dried agarose that was infused with a chemical indicator, which when exposed to the test sample results in an appropriate chromogenic outcome. The color change was then quantified by the smart camera system. The divulged instrument has been calibrated with standard buffers and also tested with clinical urine samples. The systematic study was conducted to characterize the performance of the presented technique, such as interplate variations, time variations, volume variations, and shelf life study of agarose sensor films for the commercial viability of such a technique. The employed method is competent enough to bring a change in the paradigm of dipstick method from being qualitative estimation to quantitative, manual detection to automated, and a subjective approach of diagnosis to an objective one. The technique presented here has potential application in the field of point-of-care diagnostics with high fidelity, multiplexing, and robust quantitative estimation.

  18. Exceptional Anti-Icing Performance of Self-Impregnating Slippery Surfaces. (United States)

    Stamatopoulos, Christos; Hemrle, Jaroslav; Wang, Danhong; Poulikakos, Dimos


    A heat exchange interface at subzero temperature in a water vapor environment exhibits high probability of frost formation due to freezing condensation, a factor that markedly decreases the heat transfer efficacy due to the considerable thermal resistance of ice. Here we report a novel strategy to delay ice nucleation on these types of solid-water vapor interfaces. With a process-driven mechanism, a self-generated liquid intervening layer immiscible to water is deposited on a textured superhydrophobic surface and acts as a barrier between the water vapor and the solid substrate. This liquid layer imparts remarkable slippery conditions resulting in high mobility of condensing water droplets. A large increase of the ensuing ice coverage time is shown compared to the cases of standard smooth hydrophilic or textured superhydrophobic surfaces. During deicing of these self-impregnating surfaces we show an impressive tendency of ice fragments to skate expediting defrosting. Robustness of such surfaces is also demonstrated by operating them under subcooling for at least 490 h without a marked degradation. This is attributed to the presence of the liquid intervening layer, which protects the substrate from hydrolyzation, enhancing longevity and sustaining heat transfer efficiency.


    Directory of Open Access Journals (Sweden)

    S. Komeili


    Full Text Available A series of MAl2O4 (M=Ni, Zn, and Cu aluminates were prepared by using impregnation method; the metal content of the products was ranged between 5wt% to 25wt%. The samples were characterized by x-ray diffraction (XRD, Brunauer Emmett Teller (BET surface area, NH3 temperature-programmed desorption (NH3-TPD, and inductively coupled argon plasma (ICP. The specific surface areas of zinc, nickel and copper aluminates were in the ranges of 47-77m2/g, 63-87m2/g and 1.6-3m2/g, respectively. The surface acidity decreased in the order of CuAl2O4<< NiAl2O4< ZnAl2O4<< Al2O3. By increasing the amount of metals in the samples, the number of acidic sites decreased, but their strength did not significantly change. Ni-aluminates have fewer acidic sites than Zn-aluminates, particularly in strong acid sites

  20. Isothermal relaxation current and microstructure changes of thermally aged polyester films impregnated by epoxy resin (United States)

    Jiang, Xiongwei; Sun, Potao; Peng, Qingjun; Sima, Wenxia


    In this study, to understand the effect of thermal aging on polymer films degradation, specimens of polyester films impregnated by epoxy resin with different thermal aging temperatures (80 and 130 °C) and aging times (500, 1600, 2400 and 3000 h) are prepared, then charge de-trapping properties of specimens are investigated via the isothermal relaxation current (IRC) measurement, the distributions of trap level and its corresponding density are obtained based on the modified IRC model. It is found that the deep trap density increases remarkably at the beginning of thermal aging (before 1600 h), but it decreases obviously as the aging degree increases. At elevated aging temperature and, in particular considering the presence of air gap between two-layer insulation, the peak densities of deep traps decrease more significant in the late period of aging. It can be concluded that it is the released energy from de-trapping process leads to the fast degradation of insulation. Moreover, after thermal aging, the microstructure changes of crystallinity and molecular structures are analyzed via the x-ray diffraction experiment and Fourier transform infrared spectrometer. The results indicate that the variation of the deep trap density is closely linked with the changes of microstructure, a larger interface of crystalline/amorphous phase, more defects and broken chains caused by thermal aging form higher deep trap density stored in the samples.

  1. Chronic osteomyelitis in children: treatment by intramedullary reaming and antibiotic-impregnated cement rods. (United States)

    Bar-On, Elhanan; Weigl, Daniel M; Bor, Noam; Becker, Tali; Katz, Kalman; Mercado, Eyal; Livni, Gilat


    Chronic osteomyelitis (CO) is rarely encountered in developed countries and is especially rare in children and adolescents. However, on occurrence, it can pose a difficult therapeutic challenge necessitating a combination of aggressive surgical treatment and prolonged antibiotic administration. Four patients were treated for CO in the Pediatric Orthopaedic Unit at Schneider Children's Medical Center between June 2005 and December 2006 and were reviewed retrospectively. Surgical treatment consisted of debridement and lavage, reaming of the intramedullary canal and insertion of gentamycin-impregnated polymetamethacrylate rods into the canal and beads around the infection site. At rod removal reaming and lavage were repeated. Antibiotic treatment was initiated with intravenous cephalothin, followed by prolonged oral treatment according to bacterial sensitivity. Cement rods and beads were removed 16 to 62 days after insertion. Intravenous antibiotics were continued for 6 weeks (3-13) and total antibiotic treatment length was 16 weeks (10-37). Total treatment time from presentation to full resolution averaged 8 months (2-18). One patient sustained a fracture requiring osteotomy and correction. At mean follow-up of 41 months from rod removal (36-46), all patients are asymptomatic and fully functional with no clinical signs of infection. C-reactive protein is within normal limits in all 4 patients. The method presented combining reaming, lavage and local and systemic antibiotic treatment was found to be safe and effective in the treatment of CO, eradicating the infection and preventing further tissue loss. Therapeutic study, clinical case series: level IV.

  2. Kenaf Bast Fibers—Part II: Inorganic Nanoparticle Impregnation for Polymer Composites

    Directory of Open Access Journals (Sweden)

    Jinshu Shi


    Full Text Available The objective of this study was to investigate an inorganic nanoparticle impregnation (INI technique to improve the compatibility between kenaf bast fibers and polyolefin matrices. The Scanning Electron Microscopy (SEM was used to examine the surface morphology of the INI-treated fibers showing that the CaCO3 nanoparticle crystals grew onto the fiber surface. Energy-dispersive X-ray spectroscopy (EDS was used to verify the CaCO3 nanoparticle deposits on the fiber surface. The tension tests of the individual fiber were conducted, and the results showed that the tensile strength of the fibers increased significantly (more than 20% after the INI treatments. Polymer composites were fabricated using the INI-treated fiber as reinforcement and polypropylene (PP as the matrix. The results showed that the INI treatments improved the compatibility between kenaf fibers and PP matrix. The tensile modulus and tensile strength of the composites reinforced with INI-treated fibers increased by 25.9% and 10.4%, respectively, compared to those reinforced with untreated kenaf fibers.

  3. The study of cellulosic fabrics impregnated with porphyrin compounds for use as photo-bactericidal polymers

    Energy Technology Data Exchange (ETDEWEB)

    Rahimi, Rahmatollah, E-mail: [Bioinorganic Chemistry Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran 16846-13114 (Iran, Islamic Republic of); Fayyaz, Fatemeh [Bioinorganic Chemistry Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran 16846-13114 (Iran, Islamic Republic of); Rassa, Mehdi [Department of Biology, Faculty of Science, University of Guilan, Rasht (Iran, Islamic Republic of)


    In the present work, we report on the preparation of cellulosic fabrics bearing two types of photo-sensitizers in order to prepare efficient polymeric materials for antimicrobial applications. The obtained porphyrin-grafted cellulosic fabrics were characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, diffuse reflectance UV–Vis (DRUV) spectroscopy, thermo-gravimetric analysis (TG) and scanning electron microscopy (SEM). Antimicrobial activity of the prepared porphyrin-cellulose was tested under visible light irradiation against Staphylococcus aureus, Pseudomunas aeroginosa and Escherichia coli. In addition, the effect of two parameters on photo-bactericidal activity of treated fibers was studied: illumination time and concentration of photosensitizers (PS). - Highlights: • Cellulosic fabrics were impregnated with various concentrations of porphyrins (TAPP and its zinc ion complex). • The products were characterized by ATR-FTIR, DRUV, SEM and TG. • The photo-antibacterial activity of products was determined against S. aureus, P. aeroginosa and E. coli. • The effect of two parameters were studied on photoinactivation of treated fibers: illumination time and concentration of PS.

  4. Mechanical, dielectric, and physicochemical properties of impregnating resin based on unsaturated polyesterimides (United States)

    Fetouhi, Louiza; Petitgas, Benoit; Dantras, Eric; Martinez-Vega, Juan


    This work aims to characterize the dielectric and the mechanical properties of a resin based on an unsaturated polyesterimide diluted in methacrylate reactive diluents used in the impregnation of rotating machines. The broadband dielectric spectrometry and the dynamic mechanical analysis were used to quantify the changes in dielectric and mechanical properties of the network PEI resin, as a function of temperature and frequency. The network characterizations highlight the presence of two main relaxations, α and α', confirmed by the differential scanning calorimetry analysis, showing the complexity of the chemical composition of this resin. The dielectric spectroscopy shows a significant increase in the dielectric values due to an increase of the material conductivity, while the mechanical spectroscopy shows an important decrease of the polymer rigidity and viscosity expressed by an important decrease in the storage modulus. The PEI resin shows a high reactivity when it is submitted in successive heating ramps, which involves in a post-cross-linking reaction. Contribution to the topical issue "Electrical Engineering Symposium (SGE 2016)", edited by Adel Razek

  5. Development of a Tool Condition Monitoring System for Impregnated Diamond Bits in Rock Drilling Applications (United States)

    Perez, Santiago; Karakus, Murat; Pellet, Frederic


    The great success and widespread use of impregnated diamond (ID) bits are due to their self-sharpening mechanism, which consists of a constant renewal of diamonds acting at the cutting face as the bit wears out. It is therefore important to keep this mechanism acting throughout the lifespan of the bit. Nonetheless, such a mechanism can be altered by the blunting of the bit that ultimately leads to a less than optimal drilling performance. For this reason, this paper aims at investigating the applicability of artificial intelligence-based techniques in order to monitor tool condition of ID bits, i.e. sharp or blunt, under laboratory conditions. Accordingly, topologically invariant tests are carried out with sharp and blunt bits conditions while recording acoustic emissions (AE) and measuring-while-drilling variables. The combined output of acoustic emission root-mean-square value (AErms), depth of cut ( d), torque (tob) and weight-on-bit (wob) is then utilized to create two approaches in order to predict the wear state condition of the bits. One approach is based on the combination of the aforementioned variables and another on the specific energy of drilling. The two different approaches are assessed for classification performance with various pattern recognition algorithms, such as simple trees, support vector machines, k-nearest neighbour, boosted trees and artificial neural networks. In general, Acceptable pattern recognition rates were obtained, although the subset composed by AErms and tob excels due to the high classification performances rates and fewer input variables.

  6. Removal of heavy metals in wastewater by using zeolite nano-particles impregnated polysulfone membranes

    Energy Technology Data Exchange (ETDEWEB)

    Yurekli, Yilmaz, E-mail:


    Highlights: • NaX addition significantly enhanced water hydraulic permeability of the membrane. • Metal exchange capacity of the membrane increased with the NaX content. • Hybrid membrane was efficient for the solutions with low metal concentrations - Abstract: In this study, the adsorption and the filtration processes were coupled by a zeolite nanoparticle impregnated polysulfone (PSf) membrane which was used to remove the lead and the nickel cations from synthetically prepared solutions. The results obtained from X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis indicated that the synthesized zeolite nanoparticles, using conventional hydrothermal method, produced a pure NaX with ultrafine and uniform particles. The performance of the hybrid membrane was determined under dynamic conditions. The results also revealed that the sorption capacity as well as the water hydraulic permeability of the membranes could both be improved by simply tuning the membrane fabricating conditions such as evaporation period of the casting film and NaX loading. The maximum sorption capacity of the hybrid membrane for the lead and nickel ions was measured as 682 and 122 mg/g respectively at the end of 60 min of filtration, under 1 bar of transmembrane pressure. The coupling process suggested that the membrane architecture could be efficiently used for treating metal solutions with low concentrations and transmembrane pressures.

  7. The effect of a hydroxyapatite impregnated PCL membrane in rat subcritical calvarial bone defects. (United States)

    Groppo, Monica Feresini; Caria, Paulo Henrique; Freire, Alexandre Rodrigues; Figueroba, Sidney R; Ribeiro-Neto, Wilson Alves; Bretas, Rosario Elida Suman; Prado, Felippe Bevilacqua; Haiter-Neto, Francisco; Aguiar, Flavio Henrique; Rossi, Ana Claudia


    The present study evaluated the effect of polymeric-nanofibers membranes impregnated with microparticulate hydroxyapatite (HA) in the subcritical calvarial bone defects (SCBD) healing. PCL membranes with and without HA were obtained by electrospinning. SCBD were perforated (3.3mm) in left and right sides of 36 rat calvarias. The right-side SBCD of 18 animals was filled with HA mixed with blood clot and blood clot at the contralateral side. The remaining animals received PCL+HA membrane at the right-side SCBD and PCL membrane at the contralateral side. Animals were killed after 30, 60 and 90days after surgery. Bone defect volume (in mm3) was measured by tomography (CBCT). Qualitative histological analysis and SBCD area (in mm2) were measured. Quantitative data were submitted to Kruskal-Wallis/Dunn tests. Reduction of SBCD volume was observed in all treatments but PCL. Association with HA significantly improved bone healing induced by PCL and blood clot. PCL+HA induced the lowest SBCD volume at 60 and 90days. Complete bone healing was not observed even at 90days in SCBD treated with blood clot. In every period, more bone formation was observed for SCBD treated with membranes. We concluded that both PCL membrane and HA were able to improve bone healing. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Fabrication of porous chitosan films impregnated with silver nanoparticles: a facile approach for superior antibacterial application. (United States)

    Vimala, K; Mohan, Y Murali; Sivudu, K Samba; Varaprasad, K; Ravindra, S; Reddy, N Narayana; Padma, Y; Sreedhar, B; MohanaRaju, K


    The present investigation involves the synthesis of porous chitosan-silver nanocomposite films in view of their increasing areas of application in wound dressing, antibacterial application, and water purification. The entire process consists of three-steps including silver ion-poly(ethylene glycol) matrix preparation, addition of chitosan matrix, and removal of poly(ethylene glycol) from the film matrix. Uniform porous and brown colour chitosan films impregnated with silver nanoparticles (AgNPs) were successfully fabricated by this facile approach. Both, poly(ethylene glycol) (PEG) and chitosan (CS) played vital roles in the reduction of metal ions into nanoparticles (NPs) as well as provided good stability to the formed nanoparticles. The developed porous chitosan-silver nanocomposite (PCSSNC) films were characterized by UV-vis and FTIR spectroscopy, and thermogravimetric analysis for the confirmation of nanoparticles formation. The morphology of silver nanoparticles in nanocomposite films was tested by optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The embedded AgNPs were clearly observed throughout the film in SEM and the extracted AgNPs from the porous chitosan-silver nanocomposite showed approximately 12nm in TEM. Improved mechanical properties were observed for porous chitosan-silver nanocomposite than for chitosan blend (CSB) and chitosan-silver nanocomposite (CSSNC) films. Further, the examined antibacterial activity results of these films revealed that porous chitosan-silver nanocomposite films exhibited superior inhibition.

  9. Air-Impregnated Nanoporous Anodic Aluminum Oxide Layers for Enhancing the Corrosion Resistance of Aluminum. (United States)

    Jeong, Chanyoung; Lee, Junghoon; Sheppard, Keith; Choi, Chang-Hwan


    Nanoporous anodic aluminum oxide layers were fabricated on aluminum substrates with systematically varied pore diameters (20-80 nm) and oxide thicknesses (150-500 nm) by controlling the anodizing voltage and time and subsequent pore-widening process conditions. The porous nanostructures were then coated with a thin (only a couple of nanometers thick) Teflon film to make the surface hydrophobic and trap air in the pores. The corrosion resistance of the aluminum substrate was evaluated by a potentiodynamic polarization measurement in 3.5 wt % NaCl solution (saltwater). Results showed that the hydrophobic nanoporous anodic aluminum oxide layer significantly enhanced the corrosion resistance of the aluminum substrate compared to a hydrophilic oxide layer of the same nanostructures, to bare (nonanodized) aluminum with only a natural oxide layer on top, and to the latter coated with a thin Teflon film. The hydrophobic nanoporous anodic aluminum oxide layer with the largest pore diameter and the thickest oxide layer (i.e., the maximized air fraction) resulted in the best corrosion resistance with a corrosion inhibition efficiency of up to 99% for up to 7 days. The results demonstrate that the air impregnating the hydrophobic nanopores can effectively inhibit the penetration of corrosive media into the pores, leading to a significant improvement in corrosion resistance.

  10. Antibacterial property of Ag nanoparticle-impregnated N-doped titania films under visible light (United States)

    Wong, Ming-Show; Chen, Chun-Wei; Hsieh, Chia-Chun; Hung, Shih-Che; Sun, Der-Shan; Chang, Hsin-Hou


    Photocatalysts produce free radicals upon receiving light energy; thus, they possess antibacterial properties. Silver (Ag) is an antibacterial material that disrupts bacterial physiology. Our previous study reported that the high antibacterial property of silver nanoparticles on the surfaces of visible light-responsive nitrogen-doped TiO2 photocatalysts [TiO2(N)] could be further enhanced by visible light illumination. However, the major limitation of this Ag-TiO2 composite material is its durability; the antibacterial property decreased markedly after repeated use. To overcome this limitation, we developed TiO2(N)/Ag/TiO2(N) sandwich films in which the silver is embedded between two TiO2(N) layers. Various characteristics, including silver and nitrogen amounts, were examined in the composite materials. Various analyses, including electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and ultraviolet-visible absorption spectrum and methylene blue degradation rate analyses, were performed. The antibacterial properties of the composite materials were investigated. Here we revealed that the antibacterial durability of these thin films is substantially improved in both the dark and visible light, by which bacteria, such as Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus, and Acinetobacter baumannii, could be efficiently eliminated. This study demonstrated a feasible approach to improve the visible-light responsiveness and durability of antibacterial materials that contain silver nanoparticles impregnated in TiO2(N) films.

  11. Electrochemical Removal of NOx-Gasses by Use of LSM-Cathodes Impregnated with a NOx Storage Compound

    DEFF Research Database (Denmark)

    Traulsen, Marie Lund; Kammer Hansen, Kent


    Electrochemical decomposition of NO on La0.85Sr0.15MnO3-- Ce0.90Gd0.10O1.95electrodes with and without KNO3 impregnation is investigated. The KNO3 is added as this compound is expected to work as a NOx-storage compound. Measurements are made in the temperature range 300-400 degree C and in three ...

  12. Study on Surface Damage and Performance Degradation of Impregnated Catalyst in Dielectric Barrier Discharge Plasma-Assisted Methane Conversion Processes. (United States)

    Lee, Chung Jun; Lee, Dae Hoon; Kim, Taegyu


    This paper describes the performance degradation of impregnated catalyst in the dielectric barrier discharge (DBD) plasma-assisted methane conversion process. Mn and Ni mixed copper-zinc catalysts, and bare γ-Al2O3 support were exposed to the DBD plasma generated at 1 kHz and 9 kV under CH4 direct conversion for 4 hours. The performance degradation due to the surface damage of the catalyst by the plasma was investigated by SEM analysis.

  13. Managing Coil Epoxy Vacuum Impregnation Systems at the Manufacturing Floor Level To Achieve Ultimate Properties in State-of-the-Art Magnet Assemblies

    CERN Document Server

    Hubrig, Jeffrey G


    Liquid epoxy resin impregnation systems remain a state-of-the-art polymer material for vacuum and vacuum/pressure impregnation applications in the manufacture of both advanced and conventional coil winding configurations. Epoxy resins inherent latitude in processing parameters accounts for their continued popularity in engineering applications, but also for the tendency to overlook or misinterpret the requisite processing parameters on the manufacturing floor. Resin system impregnation must be managed in detail in order to achieve device life cycle reliability. This closer look reveals how manufacturing floor level management of material acceptance, handling and storage, pre- and post- impregnation processing and cure can be built into a manufacturing plan to increase manufacturing yield, lower unit cost and ensure optimum life cycle performance of the coil.

  14. Study of the efficacy of a Wheaton coated bottle with permethrin and deltamethrin in laboratory conditions and a WHO impregnated paper with bendiocarb in field conditions

    Directory of Open Access Journals (Sweden)

    Nazaire Aïzoun


    Conclusions: The day storage and the number of times that a WHO impregnated paper and a CDC coated bottle maintained their efficacy are useful in the assessment of insecticide vectors susceptibility tests.

  15. TiO2-Impregnated Porous Silica Tube and Its Application for Compact Air- and Water-Purification Units

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Ochiai


    Full Text Available A simple, convenient, reusable, and inexpensive air- and water-purification unit including a one-end sealed porous amorphous-silica (a-silica tube coated with TiO2 photocatalyst layers has been developed. The porous a-silica layers were formed through outside vapor deposition (OVD. TiO2 photocatalyst layers were formed through impregnation and calcination onto a-silica layers. The resulting porous TiO2-impregnated a-silica tubes were evaluated for air-purification capacity using an acetaldehyde gas decomposition test. The tube (8.5 mm e.d. × 150 mm demonstrated a 93% removal rate for high concentrations (ca. 300 ppm of acetaldehyde gas at a single-pass condition with a 250 mL/min flow rate under UV irradiation. The tube also demonstrated a water purification capacity at a rate 2.0 times higher than a-silica tube without TiO2 impregnation. Therefore, the tubes have a great potential for developing compact and in-line VOC removal and water-purification units.

  16. Silanization of silica and glass slides for DNA microarrays by impregnation and gas phase protocols: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Phaner-Goutorbe, Magali, E-mail: [Universite de Lyon, Institut des Nanotechnologies de Lyon UMR 5270, Ecole Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully (France); Dugas, Vincent, E-mail: [Universite de Lyon, Universite Claude Bernard Lyon 1, Laboratoire des sciences analytiques UMR 5180, 43, bd du 11 Novembre 1918, 69622 Villeurbanne cedex (France); Chevolot, Yann, E-mail: [Universite de Lyon, Institut des Nanotechnologies de Lyon UMR 5270, Ecole Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully (France); Souteyrand, Eliane, E-mail: [Universite de Lyon, Institut des Nanotechnologies de Lyon UMR 5270, Ecole Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully (France)


    Surface immobilization of oligonucleotide probes (oligoprobes) is a key issue in the development of DNA-chips. The immobilization protocol should guarantee good availability of the probes, low non-specific adsorption and reproducibility. We have previously reported a silanization protocol with tert-butyl-11-(dimethylamino)silylundecanoate performed by impregnation (Impregnation Protocol, IP) of silica substrates from dilute silane solutions, leading to surfaces bearing carboxylic groups. In this paper, the Impregnation protocol is compared with a Gas phase Protocol (GP) which is more suited to industrial requirements such as reliable and robust processing, cost efficiency, etc.... The morphology of the oligoprobe films at the nanoscale (characterized by Atomic Force Microscopy) and the reproducibility of subsequent oligoprobes immobilization steps have been investigated for the two protocols on thermal silica (Si/SiO{sub 2}) and glass slide substrates. IP leads to smooth surfaces whereas GP induces the formation of islands features suggesting a non-continuous silane layer. The reproducibility of the overall surface layer (18.75 mm{sup 2}) has been evaluated through the covalent immobilization of a fluorescent oligoprobes. Average fluorescent signals of 6 (a.u.) and 4 (a.u.) were observed for IP and GP, respectively, with a standard deviation of 1 for both protocols. Thus, despite a morphological difference of the silane layer at the nanometer scale, the density of the immobilized probes remained similar.

  17. Knockdown and repellent effect of permethrin-impregnated army uniform cloth against Aedes aegypti after different cycles of washings. (United States)

    Sukumaran, D; Sharma, Ajay Kumar; Wasu, Yogesh H; Pandey, Pratibha; Tyagi, Varun


    Personnel protection is one of the methods for protection from bites of mosquitoes and other arthropod vectors transmitting many dreadful diseases. Insect repellents and other plant products are normally used to ward off mosquitoes. Application of synthetic pyrethroid permethrin on cloth is adopted for repelling arthropod vectors in many countries for military and civil purposes. In the present study, attempt has been made to impregnate permethrin in the army uniform cloth and to evaluate for its knockdown and repellency against unfed female Aedes aegypti mosquitoes in laboratory condition. WHO protocols were adopted for impregnation of permethrin on cloth and evaluation for its knockdown and repellency after different cycles of washing. Results showed that 93.33% of mosquitoes were knocked down within 1 h after the first washing while its efficacy reduced gradually till the fifty-fifth washing. Landing of mosquitoes on the permethrin-treated cloth was found to increase with respect to number of washings as compared to the untreated cloth. Within 24 h, 100% mortality of all the mosquitoes exposed to permethrin-impregnated cloth was observed. SEM-EDX studies on the texture of untreated cloth and permethrin-treated cloth after different cycles of washing also revealed presence of permethrin on treated cloth.

  18. Tunable aqueous polymer-phase impregnated resins-technology-a novel approach to aqueous two-phase extraction. (United States)

    van Winssen, F A; Merz, J; Schembecker, G


    Aqueous Two-Phase Extraction (ATPE) represents a promising unit operation for downstream processing of biotechnological products. The technique provides several advantages such as a biocompatible environment for the extraction of sensitive and biologically active compounds. However, the tendency of some aqueous two-phase systems to form intensive and stable emulsions can lead to long phase separation times causing an increased footprint for the required mixer-settler devices or the need for additional equipment such as centrifuges. In this work, a novel approach to improve ATPE for downstream processing applications called 'Tunable Aqueous Polymer-Phase Impregnated Resins' (TAPPIR(®))-Technology is presented. The technology is based on the immobilization of one aqueous phase inside the pores of a solid support. The second aqueous phase forms the bulk liquid around the impregnated solids. Due to the immobilization of one phase, phase emulsification and phase separation of ATPE are realized in a single step. In this study, a biodegradable and sustainable aqueous two-phase system consisting of aqueous polyethylene glycol/sodiumcitrate solutions was chosen. The impregnation of different macroporous glass and ceramic solids was investigated and could be proven to be stable. Additionally, the separation of the dye Patent blue V was successfully performed with the TAPPIR(®)-Technology. Thus, the "proof of principle" of this technology is presented. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Eucalyptus oil nanoemulsion-impregnated chitosan film: antibacterial effects against a clinical pathogen, Staphylococcus aureus, in vitro. (United States)

    Sugumar, Saranya; Mukherjee, Amitava; Chandrasekaran, Natarajan


    Eucalyptus oil (Eucalyptus globulus) nanoemulsion was formulated using low-and high-energy emulsification methods. Development of nanoemulsion was optimized for system parameters such as emulsifier type, emulsifier concentration, and emulsification methods to obtain a lower droplet size with greater stability. The minimized droplet diameter was achieved using the high-energy method of ultrasonication. Tween 80 was more effective in reducing droplet size and emulsion appearance when compared to Tween 20. Stable nanoemulsion was formulated with Tween 80 as a surfactant, and the particle size was found to be 9.4 nm (1:2 v/v). The eucalyptus oil nanoemulsion was impregnated into chitosan (1%) as a biopolymer in varying concentrations. Further, the film was characterized by moisture content, microscopic study, X-ray diffraction, and Fourier transform infrared spectroscopy. Also, the film with and without nanoemulsion was evaluated against Staphylococcus aureus. The nanoemulsion-impregnated chitosan film showed higher antibacterial activity than chitosan film. These results support the inclusion of nanoemulsion-impregnated chitosan film in wound management studies.

  20. Feeding preference of Coptotermes formosanus (Isoptera: Rhinotermitidae) for gamma-irradiated wood impregnated with benzoylphenylurea compounds under laboratory conditions. (United States)

    Katsumata, Noriaki; Tsunoda, Kunio; Toyoumi, Aya; Yoshimura, Tsuyoshi; Imamura, Yuji


    The feeding preference of Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) for 200-kGy gamma-irradiated Cryptomeria japonica D. Don (Japanese cedar) sapwood impregnated with benzoylphenylurea compounds such as hexaflumuron and noviflumuron was examined by three laboratory tests. Although termites were not deterred from feeding on gamma-irradiated wood samples that had been impregnated with hexaflumuron or noviflumuron, termite mortality was significantly higher compared with solvent controls in the no-choice test. All live termites were transferred to paper disks immediately after the no-choice test to investigate changes in mortality with time, and this test also confirmed the effects of hexaflumuron and noviflumuron on worker termites, which showed a significant feeding preference for gamma-irradiated wood. Only the 1480 ppm noviflumuron-impregnated gamma-irradiated wood specimens showed significant differences in mortality in the two-choice test. These results suggest that gamma-irradiated C. japonica wood, which is locally abundant in Japan, may have potential as a bait substrate for benzoylphenylurea compounds.