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Sample records for heat-resistant materials ii

  1. Heat-resistant materials 2. Conference proceedings of the 2. international conference on heat-resistant materials

    SciTech Connect

    Natesan, K.; Ganesan, P.; Lai, G.Y.

    1995-12-31

    The Second International Conference on Heat-Resistant Materials was held in Gatlinburg, Tennessee, September 11--14, 1995 and focused on materials performance in cross-cutting technologies where heat resistant materials play a large and sometimes life-and performance-limiting roles in process schemes. The scope of materials for heat-resistant applications included structural iron- and nickel-base alloys, intermetallics, and ceramics. The conference focused on materials development, performance of materials in simulated laboratory and actual service environments on mechanical and structural integrity of components, and state-of-the-art techniques for processing and evaluating materials performance. The three keynote talks described the history of heat-resistant materials, relationship between microstructure and mechanical behavior, and applications of these materials in process schemes. The technical sessions included alloy metallurgy and properties, environmental effects and properties, deformation behavior and properties, relation between corrosion and mechanical properties, coatings, intermetallics, ceramics, and materials for waste incineration. Seventy one papers have been processed separately for inclusion on the data base.

  2. Reaction synthesis of heat-resistant materials

    SciTech Connect

    Deevi, S.C.; Sikka, V.K.

    1995-12-31

    Exothermicity associated with the synthesis of aluminides can be utilized to obtain aluminides of transition metals. Combustion synthesis, extrusion, and hot pressing were utilized to obtain dense intermetallics and their composites. Composites were analyzed by X- ray diffraction and microscopy techniques, and tensile properties were measured on button-head and sheet specimens of intermetallics and their composites. Mechanical properties of intermetallics obtained by reaction synthesis and densification compare well with conventionally processed materials. Reaction-synthesis principles were also extended to weld overlays. Possible approaches to obtaining dense products by reaction synthesis and densification are summarized in a schematic illustration. 19 refs., 14 figs., 3 tabs.

  3. ASM specialty handbook{reg_sign}: Heat-resistant materials

    SciTech Connect

    Davis, J.R.

    1997-12-31

    This latest handbook brings together in one volume a comprehensive reference source of information on engineering metallic and nonmetallic heat-resistant materials. The volume covers the complete spectrum of technology dealing with heat-resistant materials, including high-temperature characteristics, effects of processing and microstructure on high-temperature properties, materials-selection guidelines for industrial applications and life-assessment methods. Materials covered include carbon, alloy and stainless steels; alloy cast irons; high-alloy cast steels; superalloys; titanium and titanium alloys; refractory metals and alloys; nickel-chromium and nickel-thoria alloys; structural intermetallics; structural ceramics, cermets, and cemented carbides; and carbon-carbon composites. Also included is information on property comparisons that allows ranking of alloy performance, effects of processing and microstructure on high-temperature properties, high-temperature oxidation and corrosion resistant coatings for superalloys, life-assessment methodology and design guidelines for applications involving creep and/or oxidation.

  4. Effect of Lipid Materials on Heat Resistance of Bacterial Spores

    PubMed Central

    Molin, N.; Snygg, B. G.

    1967-01-01

    The apparent heat resistance of spores of Bacillus megaterium, B. subtilis, B. cereus, B. stearothermophilus, and Clostridium botulinum type E in lipids was investigated and compared with the resistance of the spores in phosphate buffer solution. The most pronounced increase in heat resistance was noted for B. subtilis and C. botulinum type E, the increase varying with the type of lipid used. A high water content of the lipids used as heating menstruum lowered the heat resistance of the spores. Possible explanations for the high heat resistance of spores in lipids are discussed. PMID:16349757

  5. HEAT-RESISTANT MATERIAL WITH SILICON CARBIDE AS A BASE,

    DTIC Science & Technology

    A new high-temperature material, termed SG-60, is a silicon carbide -graphite composite in which the graphite is the thermostability carrier since it...is more heat-conducting and softer (heat conductivity of graphite is 0.57 cal/g-cm-sec compared with 0.02 cal/g-cm-sec for silicon carbide ) while... silicon carbide is the carrier of high-temperature strength and hardness. The high covalent bonding strength of the atoms of silicon carbide (283 kcal

  6. The Further Development of Heat-Resistant Materials for Aircraft Engines

    NASA Technical Reports Server (NTRS)

    Bollenrath, Franz

    1946-01-01

    The present report deals with the problems involved in the greater utilization and development of aircraft engine materials, and specifically; piston materials, cylinder heads, exhaust valves, and exhaust gas turbine blading. The blades of the exhaust gas turbine are likely to be the highest stressed components of modern power plants from a thermal-mechanical and chemical standpoint, even though the requirements on exhaust valves of engines with gasoline injection are in general no less stringent. For the fire plate in Diesel engines the specifications for mechanical strength and design are not so stringent, and the question of heat resistance, which under these circumstances is easier obtainable, predominates.

  7. Regularities pertinent to the cyclic heat resistance of the materials of gas-turbine blades

    NASA Astrophysics Data System (ADS)

    Nikitin, V. I.

    2008-02-01

    Long-term tests of 20 industry-grade nickel alloys were carried out, and it is established from their results that three periods are typical for their cyclic oxidation. Regularities of the processes through which oxidation develops and films are destroyed during each period, the effect the doping of alloys has on their cyclic heat resistance, and features pertinent to cyclic longevity of alloys are described.

  8. Electromagnetic property of SiO2-coated carbonyl iron/polyimide composites as heat resistant microwave absorbing materials

    NASA Astrophysics Data System (ADS)

    Wang, Hongyu; Zhu, Dongmei; Zhou, Wancheng; Luo, Fa

    2015-02-01

    Heat resistant microwave absorbing materials were prepared by compression molding method, using polyimide resin as matrix and SiO2 coated carbonyl iron (CI) as filler. The SiO2 coated CI particles were prepared by Stober process. The microwave absorbing properties and the effect of heat treatment on the electromagnetic properties of SiO2 coated CI/polyimide composites were investigated. When the content of SiO2 coated CI is 60 wt%, the value of minimum reflection loss decreases from -25 dB to -33 dB with the thickness increases from 1.5 mm to 2.1 mm. According to the thermal-gravimetric analyses (TGA) curves, the polyimide matrix can be used at 300 °C for long time. The complex permittivity of the composites slightly increases while the complex permeability almost keeps constant after heat treatment at 300 °C for 10 h, which indicating that the composites can be used at elevated temperature as microwave absorbing materials at the same time have good heat resistance and microwave absorption.

  9. Insulation Performance of Heat-Resistant Material for High-Speed Aircraft Under Thermal Environments

    NASA Astrophysics Data System (ADS)

    Wu, Dafang; Wang, Yuewu; Gao, Zhentong; Yang, Jialing

    2015-09-01

    Lightweight insulation materials are widely used to thermally protect high-speed aircraft, such as missiles. Thermal conductivity is an important parameter used to evaluate the efficiency of a material's thermal insulation performance. Since thermal conductivities provided from material handbooks or manufacturers are discrete data for different temperature ranges, there is a deviation between those and actual parameters in terms of continuous nonlinear variations. Therefore, this study measures the thermal conductivities of lightweight thermal insulation materials at high temperatures, and the relationship between the thermal conductivity and temperature is obtained. A finite element model of the thermal insulation materials is also established and applied to numerically calculate the thermal insulation properties for high-temperature ceramic fiber insulation materials using the experimentally obtained nonlinear relationship between thermal conductivity and temperature. Additionally, a transient aerodynamic heating experiment simulation system is used to thermally test the same materials; the calculated and experimental results for the same materials are compared, which exhibit good consistency that demonstrates that accurate results can be obtained from the numerical computation using the relationship established from the experimentally measured conductivity and temperature.

  10. Heat resistant materials and their feasibility issues for a space nuclear transportation system

    SciTech Connect

    Olsen, C.S.

    1991-01-01

    A number of nuclear propulsion concepts based on solid-core nuclear propulsion are being evaluated for a nuclear propulsion transportation system to support the Space Exploration Initiative (SEI) involving the reestablishment of a manned lunar base and the subsequent exploration of Mars. These systems will require high-temperature materials to meet the operating conditions with appropriate reliability and safety built into these systems through the selection and testing of appropriate materials. The application of materials for nuclear thermal propulsion (NTP) and nuclear electric propulsion (NEP) systems and the feasibility issues identified for their use will be discussed. Some mechanical property measurements have been obtained, and compatibility tests were conducted to help identify feasibility issues. 3 refs., 1 fig., 4 tabs.

  11. New materials in the aerospace industries. [emphasizing heat resistant and light alloys

    NASA Technical Reports Server (NTRS)

    Gangler, J. J.

    1973-01-01

    Trends in the development of new aerospace metals and alloys are reviewed, and applications of these advanced materials in nonaerospace fields are indicated. Emphasis is placed on the light metals and the high-temperature alloys. Attention is given to the properties and uses of the high-strength aluminum alloy 7050, alpha and beta titanium alloys, dispersion strengthened superalloys, metal-metal composites, eutectic superalloys, and coated columbium alloys.

  12. New materials in the aerospace industries. [emphasizing heat resistant and light alloys

    NASA Technical Reports Server (NTRS)

    Gangler, J. J.

    1973-01-01

    Trends in the development of new aerospace metals and alloys are reviewed, and applications of these advanced materials in nonaerospace fields are indicated. Emphasis is placed on the light metals and the high-temperature alloys. Attention is given to the properties and uses of the high-strength aluminum alloy 7050, alpha and beta titanium alloys, dispersion strengthened superalloys, metal-metal composites, eutectic superalloys, and coated columbium alloys.

  13. Research methods of plasma stream interaction with heat-resistant materials

    NASA Astrophysics Data System (ADS)

    Tyuftyaev, A. S.; Gadzhiev, M. Kh; Sargsyan, M. A.; Chinnov, V. F.; Demirov, N. A.; Kavyrshin, D. I.; Ageev, A. G.; Khromov, M. A.

    2016-11-01

    An experimental automated system was designed and constructed for studying the parameters and characteristics of non-stationary interacting system high-enthalpy-plasma stream-investigated sample: enthalpy of plasma in the incident stream; speed and temperature of plasma stream; temperature of electrons and heavy particles, ionic composition and their spatial distribution; heat flux incident on the sample (kW/cm2); surface temperature of the sample; ablation of the sample material, and others. Measurements of achievable plasma heat flux levels are carried out by calorimetry of plasma streams incident on the surface of multisection copper calorimeter. Determination of acceleration characteristics for profiled plasma torch nozzle, as well as the gas flow rate is produced by measuring the total pressure using the Pitot tube. Video visualization of interacting system is carried out using synchronized high-speed cameras. Micropyrometry of the selected zone on the sample surface is carried out by high-speed, three-wavelength pyrometer. To measure the rate of mass loss of the sample, in addition to the weighing method of evaluation the methods of laser knife and two-position stereoscopy are used. Plasma and sample emission characteristics are performed with two separate spectrometers.

  14. Occurrence and ecological distribution of Heat Resistant Moulds Spores (HRMS) in raw materials used by food industry and thermal characterization of two Talaromyces isolates.

    PubMed

    Tranquillini, Roberta; Scaramuzza, Nicoletta; Berni, Elettra

    2017-02-02

    In this study, screening of some raw materials used to produce pasteurized products was carried out to determine the occurrence and ecological distribution of heat-resistant fungi. The search for Heat Resistant Mould Spores (HRMS) resulted in the isolation of a limited number of fungal genera: Arthrinium, Aspergillus with either Eurotium-type or Neosartorya-type ascoma, Byssochlamys, Hyphodermella, Monascus, Penicillium, Rasamsonia, Talaromyces and Thermoascus. Sexual aspergilli constituted an overwhelming percentage of the mycobiota, totaling 93.5% of the heat-resistant fungi detected, and being the only fungi to be simultaneously detected in discrete concentrations on almost all matrices found positive for HRMS. Talaromyces spp., Penicillium spp. and Monascus sp. occurred at low percentages (up to 2.1%), though they were the most commonly occurring genera in lemon cells (Talaromyces, Monascus) and blueberries (Penicillium spp.). Among these isolates, two Talaromyces spp. (T. trachyspermus and T. bacillisporus) were tested for heat-resistance in both blueberry and grape juice or in buffered glucose solution, in order to assess their D- and z-values. Data obtained from thermal death curves and statistical elaboration of raw data showed that D-values of T. trachyspermus ranged between 50.0 and 90.9min at 75°C; 13.6 and 20.8min at 78°C; 5.1 and 12.4min at 80°C; 1.6 and 2.6min at 82°C. D values of T. bacillisporus ranged between 44.4 and 60.9min at 82°C; 11.9 and 15.5min at 85°C; 2.7 and 4.1min at 88°C and were equal to 1.2min at 91°C, depending on the medium. The heating times needed for inactivation were comparable to those applied to most heat-resistant species, but significantly lower than those applied to Talaromyces macrosporus or less common ascospore-forming fungal species such as Hamigera avellanea and Thermoascus crustaceus. Therefore, a traditional pasteurization process would be insufficient to avoid potential spoilage problems with T

  15. Effects of alpha-tocopherol addition to polymeric coatings on the UV and heat resistance of a fibrous collagen material--chrome-free leather

    USDA-ARS?s Scientific Manuscript database

    UV and heat resistance are very important qualities of leather because most leather products are constantly exposed to outdoor environments. In recent years, we have focused on using environmentally friendly antioxidants that will improve the UV and heat resistance of chrome-free leather. Tocopher...

  16. Heat Resistant Paint

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The racing car shown is one of many coated with an inorganic paint that protects "hot parts" of automotive vehicles. Developed and manufactured by Sperex Corporation, Gardena, California, the durable, heat-resistant paint is used on car and truck exhaust systems, firewalls, brake drums and engine manifolds. NASA technology contributed to development of the paint. Sperex was provided a technical support packa'ge detailing the research of Goddard Space Flight Center on long-life inorganic coatings. The information helped Sperex perfect its own formulations.

  17. Development and Study of Hard-Facing Materials on the Base of Heat-Resisting High-Hardness Steels for Plasma-Jet Hard- Facing in Shielding-Doping Nitrogen Atmosphere

    NASA Astrophysics Data System (ADS)

    Malushin, N. N.; Kovalev, A. P.; Valuev, D. V.; Shats, E. A.; Borovikov, I. F.

    2016-08-01

    The authors develop hard-facing materials on the base of heat-resisting highhardness steels for plasma-jet hard-facing in nitrogen atmosphere for manufacturing parts of mining and metallurgic equipment which significantly simplify the production process and effect a saving when producing bimetallic parts and tools.

  18. Heat resistant reduced activation 12% Cr steel of 16Cr12W2VTaB type-advanced structural material for fusion and fast breeder power reactors

    NASA Astrophysics Data System (ADS)

    Ioltukhovskiy, A. G.; Leonteva-Smirnova, M. V.; Solonin, M. I.; Chernov, V. M.; Golovanov, V. N.; Shamardin, V. K.; Bulanova, T. M.; Povstyanko, A. V.; Fedoseev, A. E.

    2002-12-01

    Heat resistant 12% Cr steels of the 16Cr12W2VTaB type (12Cr-2W-V-Ta-B-0.16C) provide a reduced activation material that can be used as a structural material for fusion and fast breeder reactors. The composition under study meets scientific and engineering requirements and has an optimal base element composition to provide a δ-ferrite content of no more than 20%. It also has a minimum quantity of low melting impurity elements and non-metallic inclusions. Short-term tensile properties for the steel tested to 700 °C are provided after the standard heat treatment (normalization, temper). Rupture strength and creep properties for the steel depending on the initial heat treatment conditions are also given. The microstructural stability of the 16Cr12W2VTaB type steel at temperatures up to 650 °C is predicted to be good, and the properties of the steel after irradiation in BOR-60 are demonstrated.

  19. Development of Heat-resistant XLPE Cable and Accessories

    NASA Astrophysics Data System (ADS)

    Yamada, Hiroyuki; Nakagawa, Shinichi; Murata, Yoshinao; Kishi, Kouji; Katakai, Shoshi

    We have developed heat-resistant XLPE cable and accessories that can be operated at 105°C as the maximum permissible conductor temperature in normal operation. Through this cable system, greater transmission capacity can be achieved using existing cable ducts and without increasing the conductor size of the cable. We have developed heat-resistant XLPE insulation material which has a higher melting point than that of conventional XLPE. The breakdown strength of heat-resistant XLPE cable at 105°C is almost the same as that of conventional XLPE cable at 90°C. The heat deformation of the new cable at 105°C is almost the same as that of conventional XLPE cable at 90°C. Conventional self-pressurized rubber joints can be applied to heat-resistant cable lines with the new waterproof joint compound with low heat resistivity.

  20. Heat resistant protective hand covering

    NASA Technical Reports Server (NTRS)

    Tschirch, R. P.; Sidman, K. R.; Arons, I. J. (Inventor)

    1984-01-01

    A heat-resistant aromatic polyamide fiber is described. The outer surface of the shell is coated with a fire-resistant elastomer and liner. Generally conforming and secured to the shell and disposed inwardly of the shell, the liner is made of a felt fabric of temperature-resistant aromatic polymide fiber.

  1. Study of rigid cross-linked PVC foams with heat resistance.

    PubMed

    Shi, Aihua; Zhang, Guangcheng; Zhao, Chenhui

    2012-12-13

    Three heat resistant cross-linked PVC foam plastics were prepared and their performances were compared with universal cross-linked PVC structural foam. The results show that these three heat resistant foams have higher glass transition temperatures (close to 100 °C) than universal structural foam (83.2 °C). Compared with the universal structural foam, the three heat resistant foams show much higher decomposition temperature and better chemical stability due to the crosslinking of PVC macromolecular chains. The heat distortion temperature (HDT) values of the three heat resistant foam plastics are just a little higher than that of universal structural foam. The three heat resistant foam plastics have good dimensional stability at 140 °C, and when used as core material can closely adhere to the face plates in medium temperature curing processes. Compared with universal structural foam, the three heat resistant foam plastics have slightly better mechanical properties.

  2. Heat resistant protective hand covering

    NASA Technical Reports Server (NTRS)

    Sidman, K. R.; Arons, I. J. (Inventor)

    1984-01-01

    The heat resistant, protective glove is made up of first and second shell sections which define a palm side and a backside, respectively. The first shell section is made of a twill wave fabric of a temperature-resistant aromatic polyamide fiber. The second shell section is made of a knitted fabric of a temperature-resistant aromatic polyamide fiber. The first and second shell sections are secured to one another, e.g., by sewing, to provide the desired glove configuration and an opening for insertion of the wearer's hand. The protective glove also includes a first liner section which is secured to and overlies the inner surface of the first shell section and is made of a felt fabric of a temperature-resistant aromatic polyamide fiber and has a flame resistant, elastomenic coating on the surface facing and overlying the inner surface of the first shell section.

  3. Identification of heat resistant Escherichia coli by qPCR for the locus of heat resistance.

    PubMed

    Ma, Angela; Chui, Linda

    2017-02-01

    Three qPCR assays targeting the locus of heat resistance to identify heat resistant clinical Escherichia coli isolates are described. Of 613 isolates, 3 (0.5%) possessed the locus. The assays are a rapid, highly sensitive and specific alternative to screening by heat shock and can be used in food safety surveillance.

  4. Testing Method for Heat Resistance Under Temperature Gradient

    NASA Astrophysics Data System (ADS)

    Takagi, K.; Kawasaki, A.; Itoh, Y.; Harada, Y.; Ono, F.

    2007-12-01

    “Testing Method for Heat Resistance under Temperature Gradient” is a Japanese Industrial Standard (JIS) newly established by the Minister of Economy, Trade and Industry, after deliberations by the Japanese Industrial Standards Committee, in accordance with the Industrial Standardization Law. This standard specified the testing method for heat resistance under temperature gradient of materials and coated members of equipment exposed to high temperature, such as aircraft engines, gas turbines, and so on. This paper introduces the principle and overview of the established standard. In addition, taking the heat cycle test using the burner rig for instance, we specifically illustrate the acquirable data and their analysis in the standard. Monitoring of the effective thermal conductivity and acoustic emission particularly enables to the non-destructive evaluation of failure cycle.

  5. Heat-resistant anemometers for fire research

    Treesearch

    John R. Murray; Clive M. Countryman

    1968-01-01

    Heat-resistant anemometers have been developed for measuring horizontal and vertical air flow in fire behavior studies. The anemometers will continue to produce data as long as the anemometer body is less than 650°F. They can survive brief immersion in flame without major damage. These air-flow sensors have aluminum bodies and rotor hubs and stainless steel...

  6. Method for producing heat-resistant semi-inorganic compounds

    NASA Technical Reports Server (NTRS)

    Yajima, S.; Okamura, K.; Shishido, T.; Hasegawa, Y.

    1983-01-01

    The method for producing a heat resistant, semi-inorganic compound is discussed. Five examples in which various alcohols, phenols, and aromatic carbonic acids are used to test heat resistance and solubility are provided.

  7. Evaluation of Heat Checking and Washout of Heat Resistant Superalloys and Coatings for Die inserts

    SciTech Connect

    David Schwam; John F. Wallace; Yulong Zhu; Edward Courtright; Harold Adkins

    2005-01-30

    This project had two main objectives: (1) To design, fabricate and run a full size test for evaluating soldering and washout in die insert materials. This test utilizes the unique capabilities of the 350 Ton Squeeze Casting machine available in the Case Meal Casting Laboratory. Apply the test to evaluate resistance of die materials and coating, including heat resistant alloys to soldering and washout damage. (2) To evaluate materials and coatings, including heat resistant superalloys, for use as inserts in die casting of aluminum alloys.

  8. Influence of Spore Moisture Content on the Dry-Heat Resistance of Bacillus subtilis var. niger

    PubMed Central

    Angelotti, Robert; Maryanski, James H.; Butler, Thomas F.; Peeler, James T.; Campbell, Jeptha E.

    1968-01-01

    The dry-heat resistance of Bacillus subtilis var. niger spores located in or on various materials was determined as D and z values in the range of 105 through 160 C. The systems tested included spores located on steel and paper strips, spores located between stainless-steel washers mated together under 150 inch-lb and 12 inch-lb of torque, and spores encapsulated in methylmethacrylate and epoxy plastics. D values for a given temperature varied with the test system. High D values were observed for the systems in which spores were encapsulated or under heavy torque, whereas lower D values were observed for the steel and paper strip systems and the lightly torqued system. Similar z values were obtained for the plastic and steel strip systems (zD = 21 C), but an unusually low z for spores on paper (zD = 12.9 C) and an unusually high z for spores on steel washers mated at 150 inch-lb of torque (zD = 32 C) were observed. The effect of spore moisture content on the D value of spores encapsulated in water-impermeable plastic was determined, and maximal resistance was observed for spores with a water activity (aw) of 0.2 to 0.4. Significantly decreased D values were observed for spores with moisture contents below aw 0.2 or above aw 0.4. The data indicate that the important factors to be considered when measuring the dry heat resistance of spores are (i) the initial moisture content of the spore, (ii) the rate of spore desiccation during heating, (iii) the water retention capacity of the material in or on which spores are located, and (iv) the relative humidity of the system at the test temperature. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 7 PMID:4968962

  9. Oxidation rates of some heat resistant alloys

    SciTech Connect

    Kelly, J.C.; Wilson, J.D.

    1995-12-31

    Cyclic oxidation testing of several heat resistant alloys was carried out at 1,093 and 1,149 C for times up to 3,000 hours. The quantitative results, coupled with extensive service history for the established alloys, provide a useful guide to anticipated performance of newly developed grades. Maximum practical use temperature is to some extent a function of section size, thin sheet being more quickly depleted of elements used to form the protective scale. Metallurgical factors influencing oxidation rate include grain size as well as the alloying elements silicon, manganese, molybdenum and columbium. Some comparisons are made between laboratory results and service performance.

  10. Genetic determinants of heat resistance in Escherichia coli

    PubMed Central

    Mercer, Ryan G.; Zheng, Jinshui; Garcia-Hernandez, Rigoberto; Ruan, Lifang; Gänzle, Michael G.; McMullen, Lynn M.

    2015-01-01

    Escherichia coli AW1.7 is a heat resistant food isolate and the occurrence of pathogenic strains with comparable heat resistance may pose a risk to food safety. To identify the genetic determinants of heat resistance, 29 strains of E. coli that differed in their of heat resistance were analyzed by comparative genomics. Strains were classified as highly heat resistant strains, exhibiting a D60-value of more than 6 min; moderately heat resistant strains, exhibiting a D60-value of more than 1 min; or as heat sensitive. A ~14 kb genomic island containing 16 predicted open reading frames encoding putative heat shock proteins and proteases was identified only in highly heat resistant strains. The genomic island was termed the locus of heat resistance (LHR). This putative operon is flanked by mobile elements and possesses >99% sequence identity to genomic islands contributing to heat resistance in Cronobacter sakazakii and Klebsiella pneumoniae. An additional 41 LHR sequences with >87% sequence identity were identified in 11 different species of β- and γ-proteobacteria. Cloning of the full length LHR conferred high heat resistance to the heat sensitive E. coli AW1.7ΔpHR1 and DH5α. The presence of the LHR correlates perfectly to heat resistance in several species of Enterobacteriaceae and occurs at a frequency of 2% of all E. coli genomes, including pathogenic strains. This study suggests the LHR has been laterally exchanged among the β- and γ-proteobacteria and is a reliable indicator of high heat resistance in E. coli. PMID:26441869

  11. Dry-heat resistance of selected psychrophiles.

    PubMed

    Winans, L; Pflug, I J; Foster, T L

    1977-08-01

    The dry-heat resistance characteristics of spores of psychrophilic organisms isolated from soil samples from the Viking spacecraft assembly areas at Cape Kennedy Space Flight Center, Cape Canaveral, Fla., were studied. Spore suspensions were produced, and dry-heat D values were determined for the microorganisms that demonstrated growth or survival under a simulated Martian environment. The dry-heat tests were carried out by using the planchet-boat-hot plate system at 110 and 125 degrees C with an ambient relative humidity of 50% at 22 degrees C. The spores evaluated had a relatively low resistance to dry heat. D(110 degrees C) values ranged from 7.5 to 122 min, whereas the D(123 degrees C) values ranged from less than 1.0 to 9.8 min.

  12. Frictional and heat resistance characteristics of coconut husk particle filled automotive brake pad

    NASA Astrophysics Data System (ADS)

    Bahari, Shahril Anuar; Chik, Mohd Syahrizul; Kassim, Masitah Abu; Som Said, Che Mohamad; Misnon, Mohd Iqbal; Mohamed, Zulkifli; Othman, Eliasidi Abu

    2012-06-01

    The objective of this study was to determine the friction and heat resistance characteristics of automotive brake pad composed with different sizes and percentages of coconut husk particle. The materials used were phenolic resin (phenol formaldehyde) as binder, copper, graphite and brass as friction producer/modifiers, magnesium oxide as abrasive material, steel and barium sulfate as reinforcement while coconut husk particle as filler. To obtain particle, the coconut husk was ground and dried to 3% moisture content. Then the coconut husk particle was screened using 80 mesh (to obtain coarse dust) and 100 mesh (to obtain fine dust). Different percentages of particle, such as 10 and 30% were used in the mixture of brake pad materials. Then the mixture was hot-pressed to produce brake pad. Chase machine was used to determine the friction coefficient in friction resistance testing, while thermogravimetric analyzer (TGA) machine was used to determine the heat decomposition values in heat resistance testing. Results showed that brake pad with 100 mesh and 10% composition of coconut husk particle showed the highest friction coefficient. For heat resistance, brake pad with 100 mesh and 30% composition of coconut husk dust showed the highest decomposition temperature, due to the high percentage of coconut husk particle in the composition, thus increased the thermal stability. As a comparison, brake pad composed with coconut husk particle showed better heat resistance results than commercial brake pad.

  13. A new class of bio-heat resisted polymer blend.

    NASA Astrophysics Data System (ADS)

    Pack, Seongchan; Kashiwagi, Takashi; Koga, Tadanori; Rafailovich, Miriam

    2009-03-01

    Increasing in oil prices and environmental concerns is a driving force to seek out alternative materials. A completely biodegradable starch is a candidate for the alternative materials. Since the starch is brittle, it must be mixed with other polymers. In order to make a thermoplastic starch (TPS), we need a bio-compatiblizer to increase a degree of compatibilization. The biocompatibilzer can be a small molecules or nanoparticles with the small molecules, which leads to improved material properties. In order to demonstrate a possible biocompatibilzer, we first developed a corn-based starch impregnated with non-halogenated flame retardant formulations. The starch was blended with Ecoflex, a biodegradable polymer. Using SAXS and USAXS we characterized structures of the compounds with different amount of Ecoflex by weight. Furthermore, the addition of 5% nanoparticles in the compounds increased the Young's Modulus and impact toughness significantly. The compounds also did flame test. It is indicated that the compound with the addition of the nanopaticles would pass with a UL-94V0 rating. Therefore, the procedure for producing these TPS compounds can be applied to any biodegradable polymers, manufacturing a new bio-heat resisted compound.

  14. BOOK REVIEW: Heterogeneous Materials I and Heterogeneous Materials II

    NASA Astrophysics Data System (ADS)

    Knowles, K. M.

    2004-02-01

    In these two volumes the author provides a comprehensive survey of the various mathematically-based models used in the research literature to predict the mechanical, thermal and electrical properties of hetereogeneous materials, i.e., materials containing two or more phases such as fibre-reinforced polymers, cast iron and porous ceramic kiln furniture. Volume I covers linear properties such as linear dielectric constant, effective electrical conductivity and elastic moduli, while Volume II covers nonlinear properties, fracture and atomistic and multiscale modelling. Where appropriate, particular attention is paid to the use of fractal geometry and percolation theory in describing the structure and properties of these materials. The books are advanced level texts reflecting the research interests of the author which will be of significant interest to research scientists working at the forefront of the areas covered by the books. Others working more generally in the field\

  15. Some Properties of Heat-Resistant and Heat-Sensitive Strains of Clostridium perfringens I. Heat Resistance and Toxigenicity1

    PubMed Central

    Weiss, Karl F.; Strong, Dorothy H.

    1967-01-01

    Heat resistance at 100 C (D-values), sporulating ratios, toxigenicity for mice, and lecithinase activity (as micrograms per milliliter of enzyme, ascertained by the lecithovitellin reaction) were determined for four strains of Clostridium perfringens. A definite inverse relationship between thermal resistance and toxigenicity was found. The D-values ranged from 17.6 for the most heat-resistant strain to 0.3 for the strain possessing the least heat resistance, with corresponding lecithinase activities from 25 to 133 μg/ml of enzyme. The sporulating ratios did not differ greatly between the strains. The heat stability of the toxin was greater at 100 C than at 75 C. There was a noticeable difference between the heat stabilities of the toxin in the culture fluids of the heat-sensitive and heat-resistant strains at pH 7.0 when the toxic filtrates were held at 100 C. At a holding temperature of 75 C, a similar but lesser difference was observed at pH 5.5. Heat resistance and lecithinase activity did not change when a substrain of the least heat-resistant parent strain was obtained through heat selection by a single transfer, or when the most heat-resistant strain was transferred serially 12 times. PMID:4289809

  16. Heat Resistance of Bacillus Spores at Various Relative Humidities

    PubMed Central

    Reyes, Antolin L.; Crawford, Ronald G.; Wehby, Albert J.; Peeler, James T.; Wimsatt, John C.; Campbell, Jeptha E.; Twedt, Robert M.

    1981-01-01

    The thermal resistance characteristics of spores from strains of five different Bacillus species were determined in phosphate buffer and at relative humidities ranging from <0.001 to 100% in a closed-can system. Spores tested in the closed-can system showed a marked increase in heat resistance over those in phosphate buffer, with the greatest increases occurring at relative humidities between 1 and 50%. When estimates of the time to reduce the initial spore concentration 99.99% (F value) at eight different relative humidities were plotted against temperature, three different types of heat resistance profiles were obtained, with maximum resistances at relative humidities of 1, 7, and 30%. When the various strains of spores were heated at the relative humidity of their maximum heat resistance, their relative order of heat resistance was different from that seen in buffer. Spores from the soil isolate were most resistant under these conditions (F121.1 = 99.5 h). PMID:16345868

  17. Significant effect of Ca2+ on improving the heat resistance of lactic acid bacteria.

    PubMed

    Huang, Song; Chen, Xiao Dong

    2013-07-01

    The heat resistance of lactic acid bacteria (LAB) has been extensively investigated due to its highly practical significance. Reconstituted skim milk (RSM) has been found to be one of the most effective protectant wall materials for microencapsulating microorganisms during convective drying, such as spray drying. In addition to proteins and carbohydrate, RSM is rich in calcium. It is not clear which component is critical in the RSM protection mechanism. This study investigated the independent effect of calcium. Ca(2+) was added to lactose solution to examine its influence on the heat resistance of Lactobacillus rhamnosus ZY, Lactobacillus casei Zhang, Lactobacillus plantarum P8 and Streptococcus thermophilus ND03. The results showed that certain Ca(2+) concentrations enhanced the heat resistance of the LAB strains to different extents, that is produced higher survival and shorter regrowth lag times of the bacterial cells. In some cases, the improvements were dramatic. More scientifically insightful and more intensive instrumental study of the Ca(2+) behavior around and in the cells should be carried out in the near future. In the meantime, this work may lead to the development of more cost-effective wall materials with Ca(2+) added as a prime factor. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  18. Poly(m-phenylene isophthalamide) separator for improving the heat resistance and power density of lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Zhang, Hong; Zhang, Yin; Xu, Tiange; John, Angelin Ebanezar; Li, Yang; Li, Weishan; Zhu, Baoku

    2016-10-01

    A microporous poly(m-phenylene isophthalamide) (PMIA) separator with high safety (high-heat resistance and self extinguishing), high porosity and excellent liquid electrolyte wettability was prepared by the traditional nonsolvent introduced phase separation process. Due to the high-heat resistance of PMIA material, the as-prepared separator exhibited a negligible thermal shrank ratio at 160 °C for 1 h. Meanwhile, benefiting from its high porosity and excellent wettability in liquid electrolyte, the liquid electrolyte uptake and the ionic conductivity of the separator were higher than that of the commercial PP-based separators. Furthermore, the cell assembled with this separator showed better cycling performance and superior rate capacity compared to those with PP-based separators. These results suggested that the PMIA separator is very attractive for high-heat resistance and high-power density lithium-ion batteries.

  19. Design and fabrication of heat resistant multilayers

    SciTech Connect

    Thorne, J.M.; Knight, L.V.; Peterson, B.G.; Perkins, R.T.; Gray, K.J.

    1986-01-01

    Many promising applications of multilayer x-ray optical elements subject them to intense radiation. This paper discusses the selection of optimal pairs of materials to resist heat damage and presents simulations of multilayer performance under extreme heat loadings.

  20. Bonding Heat-Resistant Fabric to Tile

    NASA Technical Reports Server (NTRS)

    Holt, J. W.; Smiser, L. W.

    1985-01-01

    Acid etching, densification, and silica cement ensure strong bond. Key step in preparation for bonding to glazed tile is etching quartz fabric and tile with acid. This increases adhesion of silica cement used to form bond. Procedures use high-temperature materials exclusively and therefore suitable for securing flexible seals and heat barriers around doors and viewing ports in furnaces and kilns.

  1. Structural Transformations in heat resistant coatings containing rare earth elements

    NASA Astrophysics Data System (ADS)

    Afanasiev, N. I.; Lepakova, O. K.; Kosova, N. I.

    2016-01-01

    Degradation of two-layered coatings and ZhS6U alloy microstructure were studied during long-term processes of high temperature annealing and creeping. It was shown that yttrium and zirconium oxides are promising as protective coatings for heat resistant nickel based alloy.

  2. Exploratory Development of Heat Resistant and Nonflammable Fibrous Materials

    DTIC Science & Technology

    1974-05-01

    fact that the government may have formulated , furnished, or in any way supplied the said drawings, specifications, or other data, is not to be...of repeated laundering was developed. providing retention ot stability through 15 wash-dry cycles in alkaline detergent . DO ♦ JAN Tl 1473... detergents . One project undertaken during the past year of the current contract was to study the effect of laundering on the thermal stability of treated

  3. Synthesis of Polyheteroarylenes for Highly Heat-Resistant Materials,

    DTIC Science & Technology

    1984-04-04

    conditions selected. Thus, fiber glass plastics based on the fabric TS-8/3-2500 and polymer POD-2 retained their ultimate strength during bending (d6S" at...oxolone, which is in the class of polybenzoxazoles . The most thermostable struc- .ure of oxolone is formed not in one stage, as that in POD-2, but in two...during the first stage, which transforms into polybenzoxazole during the second stage as a result of heat treatment under vacuum or in an inert medium

  4. Leather Coated with Mixtures of Humectant and Antioxidants to Improve UV and Heat Resistance

    USDA-ARS?s Scientific Manuscript database

    Ultraviolet (UV) and heat resistance are very important qualities for leather products. We recently developed an environmentally friendly finishing process for improving the UV- and heat resistance of automobile upholstery leather. We previously reported and demonstrated some promising results fro...

  5. Development of heat resistant polyphenol compounds applied to the spin-on carbon hardmask

    NASA Astrophysics Data System (ADS)

    Makinoshima, Takashi; Satou, Takashi; Horiuchi, Junya; Okada, Kana; Shimizu, Yoko; Echigo, Masatoshi

    2016-03-01

    In this paper, we report the development of a new polyphenol, NF7177, applied to the Spin-On Carbon Hardmask and the thermosetting properties. The new polyphenol derivatives were easily synthesized by the condensation of aldehydes and dihydroxybiphenyl compounds. We found new polyphenol NF7177 was showed the good applicability to the raw material for the Spin-On Carbon Hardmask [1]. It was indicated that the heat resistance of NF7177 was due to cross-linking based on dehydration reaction. Furthermore the thermosetting properties seem to be depend on the number and position of OH group.

  6. Production of Heat Resistant Composite based on Siloxane Elastomer and Multiwall Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Bessonov, I. V.; Karelina, N. V.; Kopitsyna, M. N.; Morozov, A. S.; Reznik, S. V.; Skidchenko, V. Yu.

    2016-02-01

    Development of a new generation of composite with unique thermal properties is an important task in the fields of science and technology where material is operated at high temperatures and exposure to a short-wave radiation. Recent studies show that carbon nanomaterials (fullerenes and carbon nanotubes) could improve the thermal, radiation and thermal-oxidative stability of the polymer matrix. In this article the development of a new heat resistant composite based on elastomer and carbon nanotubes (CNT) was performed and physicochemical properties of final product were evaluated.

  7. Incidence of heat-resistant fungi in Nsukka, southern Nigeria.

    PubMed

    Ugwuanyi, J O; Obeta, J A

    1991-06-01

    A total of 42 soil samples collected from different parts of Nsukka, Southern Nigeria, and 20 freshly plucked mango fruits were screened for the presence of heat-resistant fungi. Each soil sample, suspended in sterile water, and washings from each mango fruit were separately heated at 70 degrees C for 1 h before plating on double-strength potato dextrose agar containing chloramphenicol and incubating at approx. 28 degrees C. Approximately 98% of all soil samples and 17% of mango fruits contained heat-resistant fungi which were identified as Neosartorya fischeri, N. fischeri var. spinosa, Aspergillus flavus, Penicillium citrinum and Paecilomyces varioti which has not been reported in tropical soil. Neosartorya spp. were predominant and occurred in all positive samples. Fungal counts ranged from non-detectable to 200 colony-forming units per 10 g of soil. Most isolates appeared to grow faster at 35 degrees C than at 30 degrees C and 40 degrees C.

  8. Radiation and Heat Resistance of Moraxella-Acinetobacter in Meats

    DTIC Science & Technology

    1978-01-23

    growth 7 Vacuum packaging and impact on growth of resistant isolates .... 7 Effect of fat content of meat on radiation and heat resistance of...approximately 10 cells per ml. Storage for culture main- tenance after growth was at 3-5*C. Vacuum packaging and impact on growth of resistant isolates...sensitive to reduced oxygen occur- ring with vacuum packaging of foods (Maxcy et al., 1976). Furthermore, most of the radiation-resiscant M-A were

  9. Influence of lactic acid and post-treatment recovery time on the heat resistance of Listeria monocytogenes.

    PubMed

    Omori, Yasuo; Miake, Kiyotaka; Nakamura, Hiromi; Kage-Nakadai, Eriko; Nishikawa, Yoshikazu

    2017-09-18

    The aim of this study was to evaluate the effect of lactic acid (LA) with and without organic material at various post-treatment recovery times on the heat resistance of Listeria monocytogenes (Lm). LA decreased Lm numbers; however, the effect was remarkably attenuated by the presence of organic matter. Five strains of Lm were treated with LA and the listericidal effects were compared. The effect of LA varied depending on the strain, with ≥3.0% (w/w) LA required to kill the Lm strains in a short time. The heat resistance of Lm treated with LA was examined with respect to the time interval between the acid treatment and the subsequent manufacturing step. The heat resistance of Lm was shown to significantly increase during the post-treatment period. Heat tolerance (D value) increased up to 3.4-fold compared with the non-treated control bacteria. RNA sequencing and RT-PCR analyses suggested that several stress chaperones, proteins controlled by RecA and associated with high-temperature survival, were involved in the mechanism of enhanced heat resistance. These results are applicable to manufacturers when LA and heat treatment methods are utilized for the effective control of Lm in foods. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  10. Effect of Cu(II), Cd(II) and Zn(II) on Pb(II) biosorption by algae Gelidium-derived materials.

    PubMed

    Vilar, Vítor J P; Botelho, Cidália M S; Boaventura, Rui A R

    2008-06-15

    Biosorption of Pb(II), Cu(II), Cd(II) and Zn(II) from binary metal solutions onto the algae Gelidium sesquipedale, an algal industrial waste and a waste-based composite material was investigated at pH 5.3, in a batch system. Binary Pb(II)/Cu(II), Pb(II)/Cd(II) and Pb(II)/Zn(II) solutions have been tested. For the same equilibrium concentrations of both metal ions (1 mmol l(-1)), approximately 66, 85 and 86% of the total uptake capacity of the biosorbents is taken by lead ions in the systems Pb(II)/Cu(II), Pb(II)/Cd(II) and Pb(II)/Zn(II), respectively. Two-metal results were fitted to a discrete and a continuous model, showing the inhibition of the primary metal biosorption by the co-cation. The model parameters suggest that Cd(II) and Zn(II) have the same decreasing effect on the Pb(II) uptake capacity. The uptake of Pb(II) was highly sensitive to the presence of Cu(II). From the discrete model it was possible to obtain the Langmuir affinity constant for Pb(II) biosorption. The presence of the co-cations decreases the apparent affinity of Pb(II). The experimental results were successfully fitted by the continuous model, at different pH values, for each biosorbent. The following sequence for the equilibrium affinity constants was found: Pb>Cu>Cd approximately Zn.

  11. Systematic Assessment of Nonproteolytic Clostridium botulinum Spores for Heat Resistance

    PubMed Central

    Stringer, Sandra C.; Barker, Gary C.; Peck, Michael W.

    2016-01-01

    ABSTRACT Heat treatment is an important controlling factor that, in combination with other hurdles (e.g., pH, aw), is used to reduce numbers and prevent the growth of and associated neurotoxin formation by nonproteolytic C. botulinum in chilled foods. It is generally agreed that a heating process that reduces the spore concentration by a factor of 106 is an acceptable barrier in relation to this hazard. The purposes of the present study were to review the available data relating to heat resistance properties of nonproteolytic C. botulinum spores and to obtain an appropriate representation of parameter values suitable for use in quantitative microbial risk assessment. In total, 753 D values and 436 z values were extracted from the literature and reveal significant differences in spore heat resistance properties, particularly those corresponding to recovery in the presence or absence of lysozyme. A total of 503 D and 338 z values collected for heating temperatures at or below 83°C were used to obtain a probability distribution representing variability in spore heat resistance for strains recovered in media that did not contain lysozyme. IMPORTANCE In total, 753 D values and 436 z values extracted from literature sources reveal significant differences in spore heat resistance properties. On the basis of collected data, two z values have been identified, z = 7°C and z = 9°C, for spores recovered without and with lysozyme, respectively. The findings support the use of heat treatment at 90°C for 10 min to reduce the spore concentration by a factor of 106, providing that lysozyme is not present during recovery. This study indicates that greater heat treatment is required for food products containing lysozyme, and this might require consideration of alternative recommendation/guidance. In addition, the data set has been used to test hypotheses regarding the dependence of spore heat resistance on the toxin type and strain, on the heating technique used, and on the

  12. The locus of heat resistance (LHR) mediates heat resistance in Salmonella enterica, Escherichia coli and Enterobacter cloacae.

    PubMed

    Mercer, Ryan G; Walker, Brian D; Yang, Xianqin; McMullen, Lynn M; Gänzle, Michael G

    2017-06-01

    Enterobacteriaceae comprise food spoilage organisms as well as food-borne pathogens including Escherichia coli. Heat resistance in E. coli was attributed to a genomic island called the locus of heat resistance (LHR). This genomic island is also present in several other genera of Enterobacteriaceae, but its function in the enteric pathogens Salmonella enterica and Enterobacter cloacae is unknown. This study aimed to determine the frequency of the LHR in food isolates of E. coli, and its influence on heat resistance in S. enterica and Enterobacter spp. Cell counts of LHR-positive strains of E. coli, S. enterica and E. cloacae were reduced by less than 1, 1, and 4 log (cfu/mL), respectively, after exposure to 60 °C for 5 min, while cell counts of LHR-negative strains of the same species were reduced by more than 7 log (cfu/mL). Introducing an exogenous copy of the LHR into heat-sensitive enteropathogenic E. coli and S. enterica increased heat resistance to a level that was comparable to LHR-positive wild type strains. Cell counts of LHR-positive S. enterica were reduced by less than 1 log(cfu/mL) after heating to 60 °C for 5 min. Survival of LHR-positive strains was improved by increasing the NaCl concentration from 0 to 4%. Cell counts of LHR-positive strains of E. coli and S. enterica were reduced by less than 2 log (cfu/g) in ground beef patties cooked to an internal core temperature of 71 °C. This study indicates that LHR-positive Enterobacteriaceae pose a risk to food safety.

  13. Instructional Units for Industrial Materials, Vol. II.

    ERIC Educational Resources Information Center

    San Jose State Coll., CA.

    This second volume contains the remainder of the experiments and instructional material developed at the NDEA Institute. Included are seven units on polymers, three units on electronics, three units on graphic arts, 10 units on fuels and lubricants, and one unit on textiles. A list of reviewed films and source availability is appended. Volume I is…

  14. Polypeptide composition of urea- and heat-resistant mutants of poliovirus types 1 and 2.

    PubMed

    Fennell, R; Phillips, B A

    1974-10-01

    Five urea-resistant and two heat-resistant mutants of poliovirus types 1 and 2 were isolated and their structural and nonstructural polypeptides compared to those of their wild-type, parental strains in an attempt to correlate mutant phenotypes with alterations in specific capsid polypeptides. Four of the seven mutants were found to contain polypeptides which differed in molecular weight from their respective parental viruses. However, resistance of virions to heat- or urea-inactivation could not be attributed to changes in particular capsid polypeptides because alterations were detected in all but one of the capsid components. For two of the urea-resistant mutants and one heat-resistant mutant, no differences were found in the molecular weights of the capsid and noncapsid polypeptides. These results, and the fact that at least 12 selective treatments were required to obtain stable mutants, indicate that: (i) such phenotypes probably can be expressed by mutations affecting one or more of the larger capsid polypeptides, and (ii) such phenotypes reflect multiple mutational steps.

  15. Heat-resistant coatings for the high-pressure turbine blades of promising GTEs

    NASA Astrophysics Data System (ADS)

    Kablov, E. N.; Muboyadzhyan, S. A.

    2012-01-01

    Heat-resistant coatings are considered for the external surface of high-pressure turbine (HPT) single-crystal blades for promising gas turbine engines (GTEs) made from carbon-free nickel superalloys with rhenium or rhenium plus ruthenium. Nickel superalloys covered with heat-resistant coatings consisting of heat-resistant connecting layers and an external ZrO2-(7-8 wt %)Y2O3 ceramic layer are subjected to heat resistance and high-temperature tests. The test results are used to choose the heat-resistant layer that ensures the highest properties of a composition heat-resistant coating. The use of sequential chemical and physical deposition methods for coating layers is shown to be required to protect HPT blades in promising GTEs. Medium-frequency magnetron plasmachemical deposition of ceramic layers in heat-resistant coatings with a low thermal conductivity is found to be promising.

  16. Solubility of Structurally Complicated Materials: II. Bone

    NASA Astrophysics Data System (ADS)

    Horvath, Ari L.

    2006-12-01

    Bone is a structurally complex material, formed of both organic and inorganic chemicals. The organic compounds constitute mostly collagen and other proteins. The inorganic or bone mineral components constitute predominantly calcium, phosphate, carbonate, and a host of minor ingredients. The mineralized bone is composed of crystals which are closely associated with a protein of which collagen is an acidic polysaccharide material. This association is very close and the protein integrates into the crystalline structure. The mineralization involves the deposition of relatively insoluble crystals on an organic framework. The solubility process takes place when the outermost ions in the crystal lattice breakaway from the surface and become separated from the crystal. This is characteristic for ions dissolving in water or aqueous solutions at the specified temperature. The magnitude of solubility is temperature and pH dependent. Bone is sparingly soluble in most solvents. Enamel is less soluble than bone and fluoroapatite is the least soluble of all apatites in acid buffers. Collagen is less soluble in neutral salt solution than in dilute acid solutions at ambient temperatures. The solubility of collagens in solvents gradually decreases with increasing age of the bone samples.

  17. Heterogenous Material Integration and Band Engineering With Type II Superlattice

    DTIC Science & Technology

    2015-10-26

    AFRL-AFOSR-VA-TR-2015-0333 HETEROGENOUS MATERIAL INTEGRATION AND BAND ENGINEERING WITH TYPE II SUPERLATTICE Sanjay Krishna UNIVERSITY OF NEW MEXICO...REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE Final 3. DATES COVERED (From - To) 04/15/2010-10/14/2015 4. TITLE AND SUBTITLE "Heterogenous Material ...well as lowered size, weight, power and cost. However, despite extensive efforts on T2SL material growth, detector passivation, and fabrication, T2SL

  18. A Characterization Study of Several Heat Resistant Explosives

    DTIC Science & Technology

    1974-10-04

    explosives appear to be performing as expected. The velocities are of the same magnitude as other heat-resistant explosives such as HNS . They are lower than...the same shock sensitivity as HNS . UNCLASSIFIED 11 NOLTR 74-177 10- 10- 6 o CI1- w 0 10- 7 AH s (MOLAR) = 43.9 kCal/mole AH s (SPECIFIC) 61.5Cal/gm 10...BURNING, AND/OR EXPLOSION. [2 25 NOLTR 74 -177 TABLE I11 ELECTROSTATIC SPARK SENSITIVITY TEST RESULTS HNS -TEFLON 7C Y (ID11)TT(D182 N (D103 CAP. 90/10

  19. Heat resistant composite structure for shuttle applications (Ryton-B)

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A program was undertaken to characterize Ryton-B resin, develop graphite filament prepregs, undirectional laminates and determine the strength and heat resistance of the composite system. Through the use of a water soluble resin binder, high quality prepreg tape, three inches wide with 4 tows of HM-S were produced. The tape laminated to 0.00175 inch per ply. A wide range of properties in the cured resin and laminate were found using different curing conditions. The thermal stability and strength of molded laminates appears to be very dependent upon the cure cycle used for polymerization.

  20. Performance of a Heating Block System Designed for Studying the Heat Resistance of Bacteria in Foods.

    PubMed

    Kou, Xiao-Xi; Li, Rui; Hou, Li-Xia; Huang, Zhi; Ling, Bo; Wang, Shao-Jin

    2016-07-28

    Knowledge of bacteria's heat resistance is essential for developing effective thermal treatments. Choosing an appropriate test method is important to accurately determine bacteria's heat resistances. Although being a major factor to influence the thermo-tolerance of bacteria, the heating rate in samples cannot be controlled in water or oil bath methods due to main dependence on sample's thermal properties. A heating block system (HBS) was designed to regulate the heating rates in liquid, semi-solid and solid foods using a temperature controller. Distilled water, apple juice, mashed potato, almond powder and beef were selected to evaluate the HBS's performance by experiment and computer simulation. The results showed that the heating rates of 1, 5 and 10 °C/min with final set-point temperatures and holding times could be easily and precisely achieved in five selected food materials. A good agreement in sample central temperature profiles was obtained under various heating rates between experiment and simulation. The experimental and simulated results showed that the HBS could provide a sufficiently uniform heating environment in food samples. The effect of heating rate on bacterial thermal resistance was evaluated with the HBS. The system may hold potential applications for rapid and accurate assessments of bacteria's thermo-tolerances.

  1. Performance of a Heating Block System Designed for Studying the Heat Resistance of Bacteria in Foods

    NASA Astrophysics Data System (ADS)

    Kou, Xiao-Xi; Li, Rui; Hou, Li-Xia; Huang, Zhi; Ling, Bo; Wang, Shao-Jin

    2016-07-01

    Knowledge of bacteria’s heat resistance is essential for developing effective thermal treatments. Choosing an appropriate test method is important to accurately determine bacteria’s heat resistances. Although being a major factor to influence the thermo-tolerance of bacteria, the heating rate in samples cannot be controlled in water or oil bath methods due to main dependence on sample’s thermal properties. A heating block system (HBS) was designed to regulate the heating rates in liquid, semi-solid and solid foods using a temperature controller. Distilled water, apple juice, mashed potato, almond powder and beef were selected to evaluate the HBS’s performance by experiment and computer simulation. The results showed that the heating rates of 1, 5 and 10 °C/min with final set-point temperatures and holding times could be easily and precisely achieved in five selected food materials. A good agreement in sample central temperature profiles was obtained under various heating rates between experiment and simulation. The experimental and simulated results showed that the HBS could provide a sufficiently uniform heating environment in food samples. The effect of heating rate on bacterial thermal resistance was evaluated with the HBS. The system may hold potential applications for rapid and accurate assessments of bacteria’s thermo-tolerances.

  2. Performance of a Heating Block System Designed for Studying the Heat Resistance of Bacteria in Foods

    PubMed Central

    Kou, Xiao-xi; Li, Rui; Hou, Li-xia; Huang, Zhi; Ling, Bo; Wang, Shao-jin

    2016-01-01

    Knowledge of bacteria’s heat resistance is essential for developing effective thermal treatments. Choosing an appropriate test method is important to accurately determine bacteria’s heat resistances. Although being a major factor to influence the thermo-tolerance of bacteria, the heating rate in samples cannot be controlled in water or oil bath methods due to main dependence on sample’s thermal properties. A heating block system (HBS) was designed to regulate the heating rates in liquid, semi-solid and solid foods using a temperature controller. Distilled water, apple juice, mashed potato, almond powder and beef were selected to evaluate the HBS’s performance by experiment and computer simulation. The results showed that the heating rates of 1, 5 and 10 °C/min with final set-point temperatures and holding times could be easily and precisely achieved in five selected food materials. A good agreement in sample central temperature profiles was obtained under various heating rates between experiment and simulation. The experimental and simulated results showed that the HBS could provide a sufficiently uniform heating environment in food samples. The effect of heating rate on bacterial thermal resistance was evaluated with the HBS. The system may hold potential applications for rapid and accurate assessments of bacteria’s thermo-tolerances. PMID:27465120

  3. Heat-resistance of psychrotolerant Bacillus cereus vegetative cells.

    PubMed

    Guérin, Alizée; Dargaignaratz, Claire; Clavel, Thierry; Broussolle, Véronique; Nguyen-The, Christophe

    2017-06-01

    Spores of psychrotolerant strains of the foodborne pathogen Bacillus cereus can multiply during storage of cooked or pasteurized, refrigerated foods and can represent a risk if these cells are not eliminated during reheating of food product before consumption. We determined the heat-resistance of psychrotolerant B. cereus vegetative cells at different heating temperatures in laboratory medium and compared it with that of thermotolerant B. cereus vegetative cells. The z values, based on times for a 3 log10 reduction, of the vegetative cells of the three psychrotolerant phylogenetic groups of B. cereus varied between 3.02 °C and 4.84 °C. The temperature at which a 3 log10 reduction was achieved in 10 min varied between 47.6 °C and 49.2 °C for psychrotolerant vegetative cells and it was around 54.8 °C for thermotolerant vegetative cells. Moreover, 0.4 min at 60 °C would be sufficient for a 6 log10 CFU/ml reduction of the most heat resistant psychrotolerant B. cereus vegetative cells. These data clearly showed that psychrotolerant B. cereus vegetative cells can be rapidly eliminated by a mild heat treatment such as food reheating. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Photovoltaic module encapsulation design and materials selection. Volume II

    SciTech Connect

    Cuddihy, E.

    1984-06-01

    This is Volume II of Photovoltaic Module Encapsulation Design and Materials Selection: a periodically updated handbook of encapsulation technology, developed with the support of the Flat-Plate Solar Array Project (FSA), managed for the Department of Energy (DOE) by the Jet Propulsion Laboratory. Volume II describes FSA encapsulation technology developed between June 1, 1982, and January 1, 1984. Emphasis during this period shifted from materials development to demonstration of reliability and durability in an outdoor environment; the updated information in this volume reflects the developing technology base related to both reliability and encapsulation process improvements.

  5. Dry-heat resistance of Bacillus subtilis var. niger spores on mated surfaces.

    PubMed

    Simko, G J; Devlin, J D; Wardle, M D

    1971-10-01

    Bacillus subtilis var. niger spores were placed on the surfaces of test coupons manufactured from typical spacecraft materials (stainless steel, magnesium, titanium, and aluminum). These coupons were then juxtaposed at the inoculated surfaces and subjected to test pressures of 0, 1,000, 5,000, and 10,000 psi. Tests were conducted in ambient, nitrogen, and helium atmospheres. While under the test pressure condition, the spores were exposed to 125 C for intervals of 5, 10, 20, 50, or 80 min, with survivor data being subjected to a linear regression analysis that calculated decimal reduction times. Differences in the dry-heat resistance of the test organism resulting from pressure, atmosphere, and material were observed.

  6. Dry-Heat Resistance of Bacillus subtilis var. niger Spores on Mated Surfaces

    PubMed Central

    Simko, G. J.; Devlin, J. D.; Wardle, M. D.

    1971-01-01

    Bacillus subtilis var. niger spores were placed on the surfaces of test coupons manufactured from typical spacecraft materials (stainless steel, magnesium, titanium, and aluminum). These coupons were then juxtaposed at the inoculated surfaces and subjected to test pressures of 0, 1,000, 5,000, and 10,000 psi. Tests were conducted in ambient, nitrogen, and helium atmospheres. While under the test pressure condition, the spores were exposed to 125 C for intervals of 5, 10, 20, 50, or 80 min, with survivor data being subjected to a linear regression analysis that calculated decimal reduction times. Differences in the dry-heat resistance of the test organism resulting from pressure, atmosphere, and material were observed. Images PMID:5002136

  7. ECON 12: Student Materials. Unit II. Test Edition.

    ERIC Educational Resources Information Center

    Wiggins, Suzanne; Sperling, John

    This revision and expansion of the 1966 edition of the student materials, ED 040 101, is comprised of a student workbook and text for Unit II. It is a careful study of the structure and performance of the United States Market system including the aspects of how market competition between buyers and sellers affects resource allocation, what is…

  8. Integrated Thermal Protection Systems and Heat Resistant Structures

    NASA Technical Reports Server (NTRS)

    Pichon, Thierry; Lacoste, Marc; Glass, David E.

    2006-01-01

    In the early stages of NASA's Exploration Initiative, Snecma Propulsion Solide was funded under the Exploration Systems Research & Technology program to develop integrated thermal protection systems and heat resistant structures for reentry vehicles. Due to changes within NASA's Exploration Initiative, this task was cancelled early. This presentation provides an overview of the work that was accomplished prior to cancellation. The Snecma team chose an Apollo-type capsule as the reference vehicle for the work. They began with the design of a ceramic aft heatshield (CAS) utilizing C/SiC panels as the capsule heatshield, a C/SiC deployable decelerator and several ablators. They additionally developed a health monitoring system, high temperature structures testing, and the insulation characterization. Though the task was pre-maturely cancelled, a significant quantity of work was accomplished.

  9. Characterizing He II flow through porous materials using counterflow data

    NASA Technical Reports Server (NTRS)

    Maddocks, J. R.; Van Sciver, S. W.

    1991-01-01

    An empirical extension of the two-fluid model is used to characterize He II flow through porous materials. It is shown that four empirical parameters are necessary to describe the pressure and temperature differences induced by He II flow through a porous sample. The three parameters required to determine pressure differences are measured in counterflow and found to compare favorably with those for isothermal flow. The fourth parameter, the Gorter-Mellink constant, differs substantially from smooth tube values. It is concluded that parameter values determined from counterflow can be used to predict pressure and temperature differences in a variety of flows to an accuracy of about +/- 20 percent.

  10. Characterizing He II flow through porous materials using counterflow data

    NASA Technical Reports Server (NTRS)

    Maddocks, J. R.; Van Sciver, S. W.

    1991-01-01

    An empirical extension of the two-fluid model is used to characterize He II flow through porous materials. It is shown that four empirical parameters are necessary to describe the pressure and temperature differences induced by He II flow through a porous sample. The three parameters required to determine pressure differences are measured in counterflow and found to compare favorably with those for isothermal flow. The fourth parameter, the Gorter-Mellink constant, differs substantially from smooth tube values. It is concluded that parameter values determined from counterflow can be used to predict pressure and temperature differences in a variety of flows to an accuracy of about +/- 20 percent.

  11. Role of chelation and water binding of calcium in dormancy and heat resistance of bacterial endospores.

    PubMed

    Rajan, K S; Jaw, R; Grecz, N

    1978-06-01

    The possible relationship between the water binding by bacterial endospores and their dormancy and heat resistances has been examined in terms of the coordination characteristics of the spore-bound calcium. Stabilities of the calcium complexes of typical cytoplasmic and structural spore components were determined by potentiometric equilibrium pH measurements in model systems consisting of DPA, glycine, alanine, glutamic acid, alanyl-glutamic acid, triglycine, and tetraglycine. The Ca++-form and H+-form spores of Clostridium botulinum 33A were investigated in vivo with respect to their water sorption and heat-resistance characteristics. The results suggest that the complexing of calcium and Ca(II)-DPA may be biologically significant for spore resistance and dormancy at the following three levels: (1) complexing with spore cytoplasmic pool constituents consistent with the idea of a metal-chelate cross-linked cytoplasm or spore cement stabilizing the essential biological macromolecules, (2) complexing with structural components of the spore as indicated by the interaction with model peptides, and (3) coordination with water to produce an apparently dehydrated environment in the spore as evident from the much greater water-sorption capacity of the Ca++-form spores vs the much smaller water sorption of the H+-form spores. Interestingly enough, DPA itself, in the absence of metal ion, showed some interaction with di-, tri-, and tetrapeptides and a weak but detectable interaction with amino acids. Although the exact mode of the DPA-peptide interaction is not clear, it is attractive to speculate about its possible involvement in the control of spore dormancy and resistance.

  12. Heat Resistance of Native and Demineralized Spores of Bacillus subtilis Sporulated at Different Temperatures

    PubMed Central

    Palop, Alfredo; Sala, Francisco J.; Condón, Santiago

    1999-01-01

    Demineralization reduced heat resistance of B. subtilis spores, but the pattern and magnitude of the reduction depended on sporulation temperature and on heating menstruum pH. The differences in heat resistance of native spores caused by sporulation temperature almost disappeared after demineralization. Demineralized spores were still susceptible to the heat-sensitizing effect of acidic pH. PMID:10049900

  13. Polymeric Coatings Containing Antioxidants to Improve UV- and Heat Resistance of Chrome-Free Leather

    USDA-ARS?s Scientific Manuscript database

    For automotive upholstery leather, UV and heat resistance are very important qualities, particularly for non-chrome-tanned (chrome-free) leather. One of our research endeavors has focused on an environmentally friendly finishing process that will improve the UV and heat resistance of automobile uph...

  14. 46 CFR 128.210 - Class II vital systems-materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.210 Class II vital systems—materials... 46 Shipping 4 2010-10-01 2010-10-01 false Class II vital systems-materials. 128.210 Section 128... chapter, materials used in Class II vital piping-systems may be accepted by the cognizant OCMI or the...

  15. Viability and heat resistance of murine norovirus on bread.

    PubMed

    Takahashi, Michiko; Takahashi, Hajime; Kuda, Takashi; Kimura, Bon

    2016-01-04

    Contaminated bread was the cause of a large-scale outbreak of norovirus disease in Japan in 2014. Contamination of seafood and uncooked food products by norovirus has been reported several times in the past; however the outbreak resulting from the contamination of bread products was unusual. A few reports on the presence of norovirus on bread products are available; however there have been no studies on the viability and heat resistance of norovirus on breads, which were investigated in this study. ce:italic>/ce:italic> strain 1 (MNV-1), a surrogate for human norovirus, was inoculated directly on 3 types of bread, but the infectivity of MNV-1 on bread samples was almost unchanged after 5days at 20°C. MNV-1 was inoculated on white bread that was subsequently heated in a toaster for a maximum of 2min. The results showed that MNV-1 remained viable if the heating period was insufficient to inactivate. In addition, bread dough contaminated with MNV-1 was baked in the oven. Our results indicated that MNV-1 may remain viable on breads if the heating duration or temperature is insufficient. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Joule Heating Resistance Can Differ from Ohmic Resistance.

    NASA Astrophysics Data System (ADS)

    Saslow, Wayne M.

    1998-03-01

    For slow, steady discharge of a voltaic cell with more than one active charge-carrier, the cell's Joule heating resistance RJ differs from its Ohmic resistance R. Here RJ is determined by volume integration over the local rate of heating, J_1^2/σ1 + J_2^2/σ2 +dots (J1 is the part of the electric current due to carrier #1, σ1 is its conductivity). RJ involves only the current-carrying ions, whereas R=Δ V/I involves all of the ions because all ions contribute to the electric field and voltage Δ V across the cell. We explicitly study a well-charged lead-acid cell(W.M.Saslow, Phys.Rev.Lett. 76), 4849 (1996) and a Zn-Cu cell.(See Sect.8.1 of manuscript at http://physics.tamu.edu/ )saslow R/RJ can be greater than or less than unity.

  17. Computational design of precipitation strengthened austenitic heat-resistant steels

    NASA Astrophysics Data System (ADS)

    Lu, Qi; Xu, Wei; van der Zwaag, Sybrand

    2013-09-01

    A new genetic alloy design approach based on thermodynamic and kinetic principles is presented to calculate the optimal composition of MX carbonitrides precipitation strengthened austenitic heat-resistant steels. Taking the coarsening of the MX carbonitrides as the process controlling the life time for steels in high temperature use, the high temperature strength is calculated as a function of steel chemistry, service temperature and time. New steel compositions for different service conditions are found yielding optimal combinations of strength and stability of the strengthening precipitation for specific applications such as fire-resistant steels (short-time property guarantee) and creep-resistant steels (long-time property guarantee). Using the same modelling approach, the high temperature strength and lifetime of existing commercial austenitic creep-resistant steels were also calculated and a good qualitative agreement with reported experimental results was obtained. According to the evaluation parameter employed, the newly defined steel compositions may have higher and more stable precipitation strengthening factors than existing high-temperature precipitate-strengthened austenite steels.

  18. II-VI Materials-Based High Performance Intersubband Devices

    NASA Astrophysics Data System (ADS)

    Ravikumar, Arvind Pawan

    Mid-infrared (mid-IR) light is of vital technological importance because of its application in trace-gas absorption spectroscopy, imaging, free-space communication or infrared countermeasures. Thus the ability to generate and detect mid-IR light at low cost and preferably, at room temperature is of utmost importance. High performance quantum cascade (QC) lasers - mid-IR light sources based on optical transitions in thin quantum wells, and intersubband infrared detectors - namely the quantum well infrared photodetectors (QWIPs) and quantum cascade detectors (QCDs), have rapidly advanced, due to excellent material quality of III-V materials. In spite of this tremendous success, there lie challenges such as lack of efficient short-wavelength emitters or broadband detectors - challenges that arise from intrinsic materials properties. As a central theme in this thesis, we look at a new class of materials, the II-VI based ZnCdSe/ZnCdMgSe system, to close technological gaps and develop high performance infrared light sources and detectors in the entire mid-IR regime. To that end, we first demonstrate the flexibility that the combination of II-VI materials and band structure engineering allows by developing various QWIPs, QCDs and QC emitters at different wavelengths, not easily achieved by other materials. The performance of these first-of-their-kind detectors is already comparable to existing commercial solutions. To fully realize the potential of this new material system, we also developed a room-temperature broadband infrared detector detecting between 3 and 6 mum with record responsivity. With this technology, it is now possible to monolithically integrate high performance mid-IR lasers and detectors for on-chip applications. One of the challenges with all intersubband detectors is that they do not absorb normally incident light, like most conventional detectors. In order to make intersubband detectors attractive to commercial exploration, we develop a novel method to

  19. Heat-resistant protein expression during germination of maize seeds under water stress.

    PubMed

    Abreu, V M; Silva Neta, I C; Von Pinho, E V R; Naves, G M F; Guimarães, R M; Santos, H O; Von Pinho, R G

    2016-08-12

    Low water availability is one of the factors that limit agricultural crop development, and hence the development of genotypes with increased water stress tolerance is a challenge in plant breeding programs. Heat-resistant proteins have been widely studied, and are reported to participate in various developmental processes and to accumulate in response to stress. This study aimed to evaluate heat-resistant protein expression under water stress conditions during the germination of maize seed inbreed lines differing in their water stress tolerance. Maize seed lines 91 and 64 were soaked in 0, -0.3, -0.6, and -0.9 MPa water potential for 0, 6, 12, 18, and 24 h. Line 91 is considered more water stress-tolerant than line 64. The analysis of heat-resistant protein expression was made by gel electrophoresis and spectrophotometry. In general, higher expression of heat-resistant proteins was observed in seeds from line 64 subjected to shorter soaking periods and lower water potentials. However, in the water stress-tolerant line 91, a higher expression was observed in seeds that were subjected to -0.3 and -0.6 MPa water potentials. In the absence of water stress, heat-resistant protein expression was reduced with increasing soaking period. Thus, there was a difference in heat-resistant protein expression among the seed lines differing in water stress tolerance. Increased heat-resistant protein expression was observed in seeds from line 91 when subjected to water stress conditions for longer soaking periods.

  20. Genome-wide deficiency screen for the genomic regions responsible for heat resistance in Drosophila melanogaster

    PubMed Central

    2011-01-01

    Background Temperature adaptation is one of the most important determinants of distribution and population size of organisms in nature. Recently, quantitative trait loci (QTL) mapping and gene expression profiling approaches have been used for detecting candidate genes for heat resistance. However, the resolution of QTL mapping is not high enough to examine the individual effects of various genes in each QTL. Heat stress-responsive genes, characterized by gene expression profiling studies, are not necessarily responsible for heat resistance. Some of these genes may be regulated in association with the heat stress response of other genes. Results To evaluate which heat-responsive genes are potential candidates for heat resistance with higher resolution than previous QTL mapping studies, we performed genome-wide deficiency screen for QTL for heat resistance. We screened 439 isogenic deficiency strains from the DrosDel project, covering 65.6% of the Drosophila melanogaster genome in order to map QTL for thermal resistance. As a result, we found 19 QTL for heat resistance, including 3 novel QTL outside the QTL found in previous studies. Conclusion The QTL found in this study encompassed 19 heat-responsive genes found in the previous gene expression profiling studies, suggesting that they were strong candidates for heat resistance. This result provides new insights into the genetic architecture of heat resistance. It also emphasizes the advantages of genome-wide deficiency screen using isogenic deficiency libraries. PMID:21696597

  1. Influence of pH on heat resistance of Bacillus licheniformis in buffer and homogenised foods.

    PubMed

    Palop, A; Raso, J; Pagán, R; Condón, S; Sala, F J

    1996-02-01

    The influence of pH of heating menstruum (McIlvaine buffer) on the heat resistance of Bacillus licheniformis was investigated and compared with the heat resistance in homogenised tomato and asparagus at pH 7 and 4 in a wide range of temperatures. Heat resistance was in all mestrua smaller at acid pH. At 99 degrees C and pH 4, heat resistance was 1/20 lower than at pH 7. However, the magnitude of this effect decreased as heat treatment temperatures were increased almost disappearing at 120 degrees C. z values increased from 6.85 at pH 7, to 10.75 at pH 4. At 99 degrees C the effect of pH on heat resistance was constant along the range of pH's tested. The increase of one pH unit increased D99 by 180%. At pH 7 and 4, heat resistance was the same in buffer as in tomato and asparagus homogenates at all temperatures tested. The diminishing influence of the acidification of some foods on the heat resistance of B. licheniformis sterilisation temperatures should be taken into account when a raise in temperature is considered to shorten the duration of heat processes.

  2. Heat Resistance of Salmonella in Various Egg Products

    PubMed Central

    Garibaldi, J. A.; Straka, R. P.; Ijichi, K.

    1969-01-01

    The heat-resistance characteristics of Salmonella typhimurium Tm-1, a reference strain in the stationary phase of growth, were determined at several temperatures in the major types of products produced by the egg industry. The time required to kill 90% of the population (D value) at a given temperature in specific egg products was as follows: at 60 C (140 F), D = 0.27 min for whole egg; D = 0.60 min for whole egg plus 10% sucrose; D = 1.0 min for fortified whole egg; D = 0.20 min for egg white (pH 7.3), stabilized with aluminum; D = 0.40 min for egg yolk; D = 4.0 min for egg yolk plus 10% sucrose; D = 5.1 min for egg yolk plus 10% NaCl; D = 1.0 min for scrambled egg mix; at 55 C (131 F), D = 0.55 min for egg white (pH 9.2); D = 1.2 min for egg white (pH 9.2) plus 10% sucrose. The average Z value (number of degrees, either centigrade or fahrenheit, for a thermal destruction time curve to traverse one logarithmic cycle) was 4.6 C (8.3 F) with a range from 4.2 to 5.3 C. Supplementation with 10% sucrose appeared to have a severalfold greater effect on the heat stabilization of egg white proteins than on S. typhimurium Tm-1. This information should be of value in the formulation of heat treatments to insure that all egg products be free of viable salmonellae. Images PMID:4890741

  3. Dry-Heat Resistance of Bacterial Spores Recovered from Mariner-Mars 1969 Spacecraft

    PubMed Central

    Wardle, M. D.; Brewer, W. A.; Peterson, M. L.

    1971-01-01

    The dry-heat resistances of 70 bacterial spore isolates recovered from Mariner-Mars 1969 spacecraft were determined and expressed as D values (decimal reduction times). Fifty per cent of the spore isolates had D values of 60 min or less at 125 C. Of organisms with D values greater than 60 min, four were selected for a study of the effect of sporulation medium and suspension menstruum on dry-heat resistance. Both sporulation medium and suspension menstruum were found to affect significantly the dry-heat resistance of the bacterial spores tested. Images PMID:16349903

  4. Heat-resistant, electrically conducting joint between ceramic end plates and metallic conductors in solid oxide fuel cell

    SciTech Connect

    Wilkenhoener, R.; Buchkremer, H.P.; Stoever, D.; Stolten, D.; Koch, A.

    2000-07-01

    Ceramic parts made of doped lanthanum chromite are used as interconnects and end plates in stacks for several solid oxide fuel cell (SOFC) designs. Metallic conductors have to be attached to enable a low-resistance connection between individual stacks in each SOFC unit and to permit power to be drawn from the SOFC. The resistances of the metal-ceramic bond and the metallic conductors have to be stable under operating conditions, i.e., 1,000 C in air. Consequently, heat-resistant materials have to be used. A two-step process has been developed to connect commercially available, Ni- or Fe-based metallic conductors to ceramic SOFC end plates by vacuum furnace brazing. In the first step, a metallic sheet, which acts as the current collector, is brazed onto the ceramic end plate. Thereby, the much lower electrical conductivity of the ceramic part is compensated by that of the metal. The chromium alloy CrFe5Y{sub 2}O{sub 3}1 is suitable because it is heat-resistant, and its thermal expansion coefficient is close to that of lanthanum chromite. In the second step, metallic wires or strips are brazed on the current collector. Since this joint area is significantly smaller than that of the first joint, materials with a different thermal expansion coefficient can be used, such as conventional heat-resistant nickel alloys (Inconel 617) and ferritic stainless steels (FeCrAl 25 5). Filler alloys for both brazing steps with matching melting points have been found. Hence, both brazing steps can be performed cost-effectively in one heating step. Suitable parameters for vacuum furnace brazing of both joints are presented, and the composition of the filler alloys is given. Data concerning the long-term behavior of the joint resistances in air at 1,000 C are discussed.

  5. Ultrastructure and extreme heat resistance of spores from thermophilic Clostridium species.

    PubMed Central

    Hyun, H H; Zeikus, J G; Longin, R; Millet, J; Ryter, A

    1983-01-01

    The heat resistance and ultrastructural features of spore suspensions prepared from Clostridium thermocellum LQRI, Clostridium thermosulfurogenes 4B, and Clostridium thermohydrosulfuricum 39E were compared as a function of decimal reduction time. The decimal reduction times at 121 degrees C for strains LQRI, 4B, and 39E were 0.5, 2.5, and 11 min. The higher degree of spore heat resistance was associated with a spore architecture displaying a thicker cortex layer. Heat resistance of these spores was proportional to the ratio of spore cortex volume to cytoplasmic volume. These ratios for spores of strains LQRI, 4B, and 39E were 1.4, 1.6, and 6.6, respectively. The extreme heat resistance and autoclavable nature of C. thermohydrosulfuricum spores under routine sterilization procedures is suggested as a common cause of laboratory contamination with pure cultures of thermophilic, saccharide-fermenting anaerobes. Images PMID:6643392

  6. A study of the dry heat resistance of naturally occurring organisms widely dispersed on a surface

    NASA Technical Reports Server (NTRS)

    Garst, D. M.; Lindell, K. F.

    1971-01-01

    Although Bacillus subtilis var. niger is the standard test organism for NASA planetary quarantine sterilization studies, it was found that some naturally occurring soil organisms are more heat resistant. The separation of these organisms from soil particles is described. Experiments are discussed which were designed to show that the heat resistance is a natural characteristic of the organisms, rather than a condition induced by the clumping effect of agglomerated particles and organisms.

  7. Pasteurization of milk and the heat resistance of Mycobacterium avium subsp. paratuberculosis: a critical review of the data.

    PubMed

    Lund, Barbara M; Gould, Grahame W; Rampling, Anita M

    2002-07-25

    Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis) causes Johne's disease in ruminants (including cattle, sheep and goats) and other animals, and may contribute to Crohn's disease in humans. This possibility, and the fact that M. paratuberculosis may be present in raw milk, make it important to ensure that the heat treatment specified for pasteurization of milk will give acceptable inactivation of this bacterium, with an adequate margin of safety. Published studies of the heat resistance of this bacterium in milk have given widely differing results. Possible reasons for these differences, and the technical problems involved in the work, are reviewed. It is concluded that there is a need (i) for the adoption of an agreed Performance Criterion for pasteurization of milk in relation to this bacterium, (ii) a need for definitive laboratory experiments to understand and determine the heat resistance of M. paratuberculosis, and (iii) a need for an assessment of whether the minimum heat treatments specified at present for pasteurization of milk (Process Criteria) will meet the Performance Criterion for M. paratuberculosis. Measures are also required to ensure that commercial processes deliver continually the specified heat treatment, and to ensure that post-pasteurization contamination is avoided.

  8. Hybrid joining of polyamide and hydrogenated acrylonitrile butadiene rubber through heat-resistant functional layer of silane coupling agent

    NASA Astrophysics Data System (ADS)

    Sang, Jing; Sato, Riku; Aisawa, Sumio; Hirahara, Hidetoshi; Mori, Kunio

    2017-08-01

    A simple, direct adhesion method was developed to join polyamide (PA6) to hydrogenated acrylonitrile butadiene rubber (HNBR) by grafting a functional layer of a silane coupling agent on plasma functionalized PA6 surfaces. The functional layer of the silane coupling agent was prepared using a self-assembly method, which greatly improved the heat resistance of PA6 from 153 °C up to 325 °C and the resulting PA6/HNBR joints showed excellent adhesion properties with cohesive failure between PA6 and HNBR. X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and nanoscale infrared microscopy and chemical imaging (Nano-IR, AFM-IR) were employed to characterize the surfaces and interfaces. The Nano-IR analysis method was employed for the first time to analyze the chemical structures of the adhesion interfaces between different materials and to establish the interface formation mechanism. This study is of significant value for interface research and the study of adhesion between resins and rubbers. There is a promising future for heat-resistant functional layers on resin surfaces, with potential application in fuel hose composite materials for the automotive and aeronautical industries.

  9. Confined dense circumstellar material surrounding a regular type II supernova

    NASA Astrophysics Data System (ADS)

    Yaron, O.; Perley, D. A.; Gal-Yam, A.; Groh, J. H.; Horesh, A.; Ofek, E. O.; Kulkarni, S. R.; Sollerman, J.; Fransson, C.; Rubin, A.; Szabo, P.; Sapir, N.; Taddia, F.; Cenko, S. B.; Valenti, S.; Arcavi, I.; Howell, D. A.; Kasliwal, M. M.; Vreeswijk, P. M.; Khazov, D.; Fox, O. D.; Cao, Y.; Gnat, O.; Kelly, P. L.; Nugent, P. E.; Filippenko, A. V.; Laher, R. R.; Wozniak, P. R.; Lee, W. H.; Rebbapragada, U. D.; Maguire, K.; Sullivan, M.; Soumagnac, M. T.

    2017-02-01

    With the advent of new wide-field, high-cadence optical transient surveys, our understanding of the diversity of core-collapse supernovae has grown tremendously in the last decade. However, the pre-supernova evolution of massive stars, which sets the physical backdrop to these violent events, is theoretically not well understood and difficult to probe observationally. Here we report the discovery of the supernova iPTF 13dqy = SN 2013fs a mere ~3 h after explosion. Our rapid follow-up observations, which include multiwavelength photometry and extremely early (beginning at ~6 h post-explosion) spectra, map the distribution of material in the immediate environment (<~1015 cm) of the exploding star and establish that it was surrounded by circumstellar material (CSM) that was ejected during the final ~1 yr prior to explosion at a high rate, around 10-3 solar masses per year. The complete disappearance of flash-ionized emission lines within the first several days requires that the dense CSM be confined to within <~1015 cm, consistent with radio non-detections at 70-100 days. The observations indicate that iPTF 13dqy was a regular type II supernova; thus, the finding that the probable red supergiant progenitor of this common explosion ejected material at a highly elevated rate just prior to its demise suggests that pre-supernova instabilities may be common among exploding massive stars.

  10. Characterizing He II flow through porous materials using counterflow data

    NASA Technical Reports Server (NTRS)

    Maddocks, J. R., Jr.; Vansciver, Steven W.

    1990-01-01

    Proposed space applications, such as the cooling of infrared and x ray telescopes, have generated substantial interest in the behavior of He II flowing in porous materials. For design purposes, classical porous media correlations and room temperature data are often used to obtain order of magnitude estimates of expected pressure drops, while the attendant temperature differences are either ignored or estimated using smooth tube correlations. A more accurate alternative to this procedure is suggested by an empirical extension of the two fluid model. It is shown that four empirical parameters are necessary to describe the pressure and temperature differences induced by He II flow through a porous sample. The three parameters required to determine pressure differences are measured in counterflow and found to compare favorably with those for isothermal flow. The fourth parameter, the Gorter-Mellink constant, differs substantially from smooth tube values. It is concluded that parameter values determined from counterflow can be used to predict pressure and temperature differences in a variety of flows to an accuracy of about + or - 20 pct.

  11. A Ferroelectric Iron(II) Spin Crossover Material.

    PubMed

    Jornet-Mollá, Verónica; Duan, Yan; Giménez-Saiz, Carlos; Tang, Yuan-Yuan; Li, Peng-Fei; Romero, Francisco M; Xiong, Ren-Gen

    2017-09-07

    A dual-function material in which ferroelectricity and spin crossover coexist in the same temperature range has been obtained. Our synthetic strategy allows the construction of acentric crystal structures in a predictable way and is based on the high directionality of hydrogen bonds. The well-known iron(II) spin crossover complex [Fe(bpp)2 ](2+) (bpp=2,6-bis(pyrazol-3-yl)pyridine), a four-fold noncentrosymmetric H-bond donor, was combined with a disymmetric H-bond acceptor such as the isonicotinate (isonic) anion to afford [Fe(bpp)2 ](isonic)2 ⋅2 H2 O. This low-spin iron(II) compound crystallizes in the acentric nonpolar I4‾ space group and shows piezoelectricity and SHG properties. Upon dehydration, it undergoes a single-crystal to single-crystal structural rearrangement to a monoclinic polar Pc phase that is ferroelectric and exhibits spin crossover. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Microstructural characterization of dissimilar welds between alloy 800 and HP heat-resistant steel

    SciTech Connect

    Dehmolaei, R.; Shamanian, M. Kermanpur, A.

    2008-10-15

    In this study, dissimilar welds between HP heat-resistant steel and Incoloy 800 were made with four different filler materials including: 309 stainless steel and nickel-based Inconel 82, 182 and 617. The microstructure of the base metals, weld metals and their interfaces were characterized by utilizing optical and scanning electron microscopy. Grain boundaries migration in the weld metals was studied. It was found that the migration of grain boundaries in the Inconel 82 weld metal was very extensive. Precipitates of TiC and M{sub 23}C{sub 6} (M = Cr and Mo) in the Inconel 617 weld metal are identified. The necessary conditions for the formation of cracks close to the fusion line of the 309-HP joints are described. Furthermore unmixed zone near the fusion line between HP steel base metal and Inconel 82 weld metal is discussed. An epitaxial growth is characterized at the fusion line of the 309-Alloy 800 and Inconel 617-Alloy 800 joints.

  13. Some Like It Hot: Heat Resistance of Escherichia coli in Food

    PubMed Central

    Li, Hui; Gänzle, Michael

    2016-01-01

    Heat treatment and cooking are common interventions for reducing the numbers of vegetative cells and eliminating pathogenic microorganisms in food. Current cooking method requires the internal temperature of beef patties to reach 71°C. However, some pathogenic Escherichia coli such as the beef isolate E. coli AW 1.7 are extremely heat resistant, questioning its inactivation by current heat interventions in beef processing. To optimize the conditions of heat treatment for effective decontaminations of pathogenic E. coli strains, sufficient estimations, and explanations are necessary on mechanisms of heat resistance of target strains. The heat resistance of E. coli depends on the variability of strains and properties of food formulations including salt and water activity. Heat induces alterations of E. coli cells including membrane, cytoplasm, ribosome and DNA, particularly on proteins including protein misfolding and aggregations. Resistant systems of E. coli act against these alterations, mainly through gene regulations of heat response including EvgA, heat shock proteins, σE and σS, to re-fold of misfolded proteins, and achieve antagonism to heat stress. Heat resistance can also be increased by expression of key proteins of membrane and stabilization of membrane fluidity. In addition to the contributions of the outer membrane porin NmpC and overcome of osmotic stress from compatible solutes, the new identified genomic island locus of heat resistant performs a critical role to these highly heat resistant strains. This review aims to provide an overview of current knowledge on heat resistance of E. coli, to better understand its related mechanisms and explore more effective applications of heat interventions in food industry. PMID:27857712

  14. 46 CFR 128.220 - Class II non-vital systems-materials and pressure design.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SUPPLY VESSELS MARINE ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.220 Class II non-vital systems—materials and pressure design. (a) Except as provided by §§ 128.230, 128.240, and... 46 Shipping 4 2010-10-01 2010-10-01 false Class II non-vital systems-materials and pressure design...

  15. Type-II superlattice materials for mid-infrared detection

    NASA Astrophysics Data System (ADS)

    Brown, Gail J.; Haugan, Heather; Szmulowicz, Frank; Mahalingam, Krishnamur; Grazulis, L.; Houston, Shanee

    2005-03-01

    Type-II superlattices composed of alternating thin layers of InAs and GaSb, have been shown to be a highly flexible infrared materials system in which the energy band gap can be adjusted anywhere between 360 meV and 40 meV. These superlattices (SLs) are the III-V equivalent to the well established HgxCd1-xTe alloys used for infrared detection in the short, mid and long wavelength bands of the infrared spectrum. There are many possible designs for these superlattices that will produce the same narrow band gap by adjusting individual layer thicknesses and interface composition. Systematic growth and characterization studies were performed to determine optimum superlattice designs suitable for infrared detection in the 3 to 5 μm wavelength band. For these studies the individual layer thicknesses were less than 35Å. The effects of adding different thickness InSb-like interfaces were also studied. Through precision molecular beam epitaxy, design changes as small as 3Å to the SL layers could be studied. Significant changes were observed in the infrared photoresponse spectra of the various SL samples. The infrared properties of the various designs of these type-II superlattices were modeled using an 8-band Envelope Function Approximation. The infrared photoresponse spectra, combined with quantum mechanical modeling of predicted absorption spectra, were a key factor in the design optimization of the InAs/GaSb superlattices with band gaps in the range of 200 to 360 meV.

  16. American Material Culture: Investigating a World War II Trash Dump

    SciTech Connect

    Julie Braun

    2005-10-01

    The Idaho National Laboratory: An Historical Trash Trove Historians and archaeologists love trash, the older the better. Sometimes these researchers find their passion in unexpected places. In this presentation, the treasures found in a large historic dump that lies relatively untouched in the middle of the Idaho National Laboratory (INL) will be described. The U.S. military used the central portion of the INL as one of only six naval proving grounds during World War II. They dumped trash in dry irrigation canals during and after their wartime activities and shortly before the federal government designated this arid and desolate place as the nation’s nuclear reactor testing station in 1949. When read critically and combined with memories and photographs, the 60-year old trash provides a glimpse into 1940s’ culture and the everyday lives of ordinary people who lived and worked during this time on Idaho’s desert. Thanks to priceless stories, hours of research, and the ability to read the language of historic artifacts, the dump was turned from just another trash heap into a treasure trove of 1940s memorabilia. Such studies of American material culture serve to fire our imaginations, enrich our understanding of past practices, and humanize history. Historical archaeology provides opportunities to integrate inanimate objects with animated narrative and, the more recent the artifacts, the more human the stories they can tell.

  17. Heat resistance of an outbreak strain of Listeria monocytogenes in hot dog batter.

    PubMed

    Mazzotta, A S; Gombas, D E

    2001-03-01

    The heat resistance of a strain of Listeria monocytogenes responsible for a listeriosis outbreak in hot dogs was not higher than the heat resistance of other L. monocytogenes strains when tested in tryptic soy broth and in laboratory-prepared hot dog batter. For the thermal death time experiments, the cells were grown to stationary phase or were starved in phosphate-buffered saline, pH 7, for 6 h at 30 degrees C. Starvation increased the heat resistance of L. monocytogenes in broth but not in hot dog batter. D-values in hot dog batter were higher than in broth. For the hot dog formulation used in this study, cooking the hot dog batter for 30 s at 71.1 degrees C (160 degrees F), or its equivalent using a z-value of 6 degrees C (11 degrees F), would inactivate 5 logs of L. monocytogenes.

  18. Functional Analysis of Genes Comprising the Locus of Heat Resistance in Escherichia coli.

    PubMed

    Mercer, Ryan; Nguyen, Oanh; Ou, Qixing; McMullen, Lynn; Gänzle, Michael G

    2017-10-15

    The locus of heat resistance (LHR) is a 15- to 19-kb genomic island conferring exceptional heat resistance to organisms in the family Enterobacteriaceae, including pathogenic strains of Salmonella enterica and Escherichia coli The complement of LHR-comprising genes that is necessary for heat resistance and the stress-induced or growth-phase-induced expression of LHR-comprising genes are unknown. This study determined the contribution of the seven LHR-comprising genes yfdX1GI, yfdX2, hdeDGI, orf11, trxGI, kefB, and psiEGI by comparing the heat resistances of E. coli strains harboring plasmid-encoded derivatives of the different LHRs in these genes. (Genes carry a subscript "GI" [genomic island] if an ortholog of the same gene is present in genomes of E. coli) LHR-encoded heat shock proteins sHSP20, ClpKGI, and sHSPGI are not sufficient for the heat resistance phenotype; YfdX1, YfdX2, and HdeD are necessary to complement the LHR heat shock proteins and to impart a high level of resistance. Deletion of trxGI, kefB, and psiEGI from plasmid-encoded copies of the LHR did not significantly affect heat resistance. The effect of the growth phase and the NaCl concentration on expression from the putative LHR promoter p2 was determined by quantitative reverse transcription-PCR and by a plasmid-encoded p2:GFP promoter fusion. The expression levels of exponential- and stationary-phase E. coli cells were not significantly different, but the addition of 1% NaCl significantly increased LHR expression. Remarkably, LHR expression in E. coli was dependent on a chromosomal copy of evgA In conclusion, this study improved our understanding of the genes required for exceptional heat resistance in E. coli and factors that increase their expression in food.IMPORTANCE The locus of heat resistance (LHR) is a genomic island conferring exceptional heat resistance to several foodborne pathogens. The exceptional level of heat resistance provided by the LHR questions the control of pathogens by

  19. Heat-resistant fungi of importance to the food and beverage industry.

    PubMed

    Tournas, V

    1994-01-01

    Spoilage of pasteurized and canned fruit and fruit products caused by heat-resistant molds have been reported repeatedly in recent years. Species most commonly implicated in fruit and fruit product disintegration are Byssochlamys fulva, Byssochlamys nivea, Neosartorya fischeri, Talaromyces flavus, and Eupenicillium brefeldianum. These organisms are saprophytic rather than parasitic and usually contaminate fruits on or near the ground. They can survive heat treatments used for fruit processing and can grow and spoil the products during storage at room temperature, which results in great economic losses. Mold heat resistance is attributed to the formation of sexual spores, ascospores. Ascospores have a wide range of heat resistance, depending on species, strain, age of organism, heating medium, pH, presence of sugars, fats, and acids in heating medium, growth conditions, etc. The mechanism(s) of thermoresistance are not clear; probably some very stable compound(s) critical to germination and outgrowth are present in the heat-resistant ascospores. Besides spoilage, the heat-resistant molds produce a number of toxic secondary metabolites, such as byssotoxin A; byssochlamic acid; the carcinogen, patulin, the tremorgenic substances, fumitremorgin A and C, and verruculogen; fischerin, which caused fatal peritonitis in mice; and eupenifeldin, a compound possessing cytotoxicity as well as in vivo antitumor activity. Growth of heat-resistant fungi can be controlled by lowering the water activity, adding sulfur dioxide, sorbate, or benzoate; washing of fruits in hypochlorite solution before heat treatment reduces the number of ascospores and makes the heat destruction more successful. More research is needed to elucidate the mechanism(s) of thermoresistance and develop new methods for the complete inactivation of resistant ascospores.

  20. 46 CFR 128.210 - Class II vital systems-materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... chapter, materials used in Class II vital piping-systems may be accepted by the cognizant OCMI or the Commanding Officer, Marine Safety Center, if shown to provide a level of safety equivalent to materials in...

  1. 46 CFR 128.210 - Class II vital systems-materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... chapter, materials used in Class II vital piping-systems may be accepted by the cognizant OCMI or the Commanding Officer, Marine Safety Center, if shown to provide a level of safety equivalent to materials in...

  2. Heat-resistant metals in Mendeleev's periodic table

    NASA Astrophysics Data System (ADS)

    Podberezskaya, N. V.

    2012-11-01

    The data from the Inorganic Crystal Structure Database (ICSD, version 1.7.1, 2010-2) on refractory elements of Mendeleev's periodic table have been analyzed. Insight is gained into the current state of structural studies of simple materials, the number of polymorphs, and their symmetry.

  3. Recalling Prerequisite Material in a Calculus II Course to Improve Student Success

    ERIC Educational Resources Information Center

    Mokry, Jeanette

    2016-01-01

    This article discusses preparation assignments used in a Calculus II course that cover material from prerequisite courses. Prior to learning new material, students work on problems outside of class involving concepts from algebra, trigonometry, and Calculus I. These problems are directly built upon in order to answer Calculus II questions,…

  4. Recalling Prerequisite Material in a Calculus II Course to Improve Student Success

    ERIC Educational Resources Information Center

    Mokry, Jeanette

    2016-01-01

    This article discusses preparation assignments used in a Calculus II course that cover material from prerequisite courses. Prior to learning new material, students work on problems outside of class involving concepts from algebra, trigonometry, and Calculus I. These problems are directly built upon in order to answer Calculus II questions,…

  5. Mixed sulfidation/carburization attack on several heat-resistant alloys at 900 C

    SciTech Connect

    Harper, M.A.; Cotner, J.P.

    2000-06-01

    A sulfidation/carburization study of seven commercial heat-resistant alloys was carried out at 900 C in a H{sub 2}-25 vol.%CH{sub 4}-14.8N{sub 2}-4CO-0.6CO{sub 2}-0.6H{sub 2}S atmosphere. The equilibrium partial pressures for oxygen (O{sub 2}) and sulfur (S{sub 2}) were 1.1 x 10{sup {minus}22} and 4.1 x 10{sup {minus}8} atm, respectively, and the carbon activity for this system was unity. The time of exposure was 500 hr. Relatively thick, mixed sulfide scales were formed on all of the alloys tested. In addition, internal carburization occurred in all of the alloys. Using metal loss (i.e., the reduction in sample thickness) plus internal attack (internal sulfidation plus internal carburization) as a performance criterion, an alloy with a nominal composition of Ni-29 wt.%Co-28Cr-2.75Si performed the best, showing 0.71 mm of attack. An alloy with a nominal composition of Fe-20 wt.%Ni-25Cr performed the worst, being totally consumed by the test (>3.18 mm of attack). Alloys containing relatively high amounts of silicon (> 2.5%) showed a dramatic increase in their sulfidation resistance compared to the other alloys containing lower silicon contents. The amount of iron present within a given material played a dominant role in the carburization attack that occurred, with as expected, high-iron alloys showing significant internal carburization because of a high solubility and diffusivity of carbon in the matrix. The importance of the various alloying elements with respect to sulfidation and carburization resistance is discussed.

  6. Heat resistance of Alicyclobacillus acidocaldarius in water, various buffers, and orange juice.

    PubMed

    Palop, A; Alvarez, I; Raso, J; Condón, S

    2000-10-01

    The effect of the pH or the composition of the heating medium and of the sporulation temperature on the heat resistance of spores of a thermoacidophilic spore-forming microorganism isolated from a dairy beverage containing orange fruit concentrate was investigated. The species was identified as Alicyclobacillus acidocaldarius. The spores showed the same heat resistance in citrate-phosphate buffers of pH 4 and 7, in distilled water, and in orange juice at any of the temperatures tested (D120 degrees C = 0.1 min and z = 7 degrees C). A raise in 20 degrees C in the sporulation temperature (from 45 to 65 degrees C) increased the heat resistance eightfold (from D110 degrees C = 0.48 min when sporulated at 45 degrees C to 3.9 min when sporulated at 65 degrees C). The z-values remained constant for all sporulation temperatures. The spores of this strain of A. acidocaldarius were very heat resistant and could easily survive any heat treatment currently applied to pasteurize fruit juices.

  7. Microstructural stability of 9-12%Cr ferrite/martensite heat-resistant steels

    NASA Astrophysics Data System (ADS)

    Yan, Wei; Wang, Wei; Shan, Yi-Yin; Yang, Ke

    2013-03-01

    The microstructural evolutions of advanced 9-12%Cr ferrite/martensite heat-resistant steels used for power generation plants are reviewed in this article. Despite of the small differences in chemical compositions, the steels share the same microstructure of the as-tempered martensite. It is the thermal stability of the initial microstructure that matters the creep behavior of these heat-resistant steels. The microstructural evolutions involved in 9-12%Cr ferrite heat-resistant steels are elaborated, including (1) martensitic lath widening, (2) disappearance of prior austenite grain boundary, (32) emergence of subgrains, (4) coarsening of precipitates, and (5) formation of new precipitates, such as Laves-phase and Z-phase. The former three microstructural evolutions could be retarded by properly disposing the latter two. Namely improving the stability of precipitates and optimizing their size distribution can effectively exert the beneficial influence of precipitates on microstructures. In this sense, the microstructural stability of the tempered martensite is in fact the stability of precipitates during the creep. Many attempts have been carried out to improve the microstructural stability of 9-12%Cr steels and several promising heat-resistant steels have been developed.

  8. Quantifying variety-specific heat resistance and the potential for adaptation to climate change.

    PubMed

    Tack, Jesse; Barkley, Andrew; Rife, Trevor W; Poland, Jesse A; Nalley, Lawton Lanier

    2016-08-01

    The impact of climate change on crop yields has become widely measured; however, the linkages for winter wheat are less studied due to dramatic weather changes during the long growing season that are difficult to model. Recent research suggests significant reductions under warming. A potential adaptation strategy involves the development of heat resistant varieties by breeders, combined with alternative variety selection by producers. However, the impact of heat on specific wheat varieties remains relatively unstudied due to limited data and the complex genetic basis of heat tolerance. Here, we provide a novel econometric approach that combines field-trial data with a genetic cluster mapping to group wheat varieties and estimate a separate extreme heat impact (temperatures over 34 °C) across 24 clusters spanning 197 varieties. We find a wide range of heterogeneous heat resistance and a trade-off between average yield and resistance. Results suggest that recently released varieties are less heat resistant than older varieties, a pattern that also holds for on-farm varieties. Currently released - but not yet adopted - varieties do not offer improved resistance relative to varieties currently grown on farm. Our findings suggest that warming impacts could be significantly reduced through advances in wheat breeding and/or adoption decisions by producers. However, current adaptation-through-adoption potential is limited under a 1 °C warming scenario as increased heat resistance cannot be achieved without a reduction in average yields. © 2015 John Wiley & Sons Ltd.

  9. A summary of research on heat resistant fabrics for protective clothing

    SciTech Connect

    Brewster, E.P.; Barker, R.L.

    1983-02-01

    Reference is made to research on the performance of heat-resistant safety fabrics. General requirements for fabrics used for thermal protection are discussed, and laboratory methods of testing are summarized. A need is seen for a specific programme to evaluate the suitability of the variety of fabrics that might be used in industrial safety apparel.

  10. OTS Selective Bibliography. High Temperature Metallurgy and Heat Resistant Alloys

    DTIC Science & Technology

    1961-02-01

    Order from OTS at 75 cents PB 151083 thermite reactions were studies with regard to throt- tling materials (alumina versus kaolin , EPK), binders SELECTED...THERMODYNAMICS OF MOLTEN ALLOYS (Dilute solutions of metals - bibliography), by Goodwin and Ayton. sulphur in liquid tin and lead. Sn-Cu-S, Sn-Ag-S...1958, no. 6, p. 41-47. sulphur dioxide), by Makolkin. 1959. llp. Order as HB-4253 from HB at $4.90 59-14611 Trans. of Zhurnal Prikladnoy Khimii (USSR

  11. Chromium(II) Metal-Organic Polyhedra as Highly Porous Materials.

    PubMed

    Park, Jinhee; Perry, Zachary; Chen, Ying-Pin; Bae, Jaeyeon; Zhou, Hong-Cai

    2017-08-23

    Herein we report for the first time the synthesis of Cr(II)-based metal-organic polyhedra (MOPs) and the characterization of their porosities. Unlike the isostructural Cu(II)- or Mo(II)-based MOPs, Cr(II)-based MOPs show unusually high gas uptakes and surface areas. The combination of comparatively robust dichromium paddlewheel units (Cr2 units), cage symmetries, and packing motifs enable these materials to achieve Brunauer-Emmett-Teller surface areas of up to 1000 m(2)/g. Reducing the aggregation of the Cr(II)-based MOPs upon activation makes their pores more accessible than their Cu(II) or Mo(II) counterparts. Further comparisons of surface areas on a molar (m(2)/mol cage) rather than gravimetric (m(2)/g) basis is proposed as a rational method of comparing members of a family of related molecular materials.

  12. Biofilm Formation Potential of Heat-Resistant Escherichia coli Dairy Isolates and the Complete Genome of Multidrug-Resistant, Heat-Resistant Strain FAM21845

    PubMed Central

    Schmid, Michael; Kulli, Sandra; Schneeberger, Kerstin; Naskova, Javorka; Knøchel, Susanne; Ahrens, Christian H.

    2017-01-01

    ABSTRACT We tested the biofilm formation potential of 30 heat-resistant and 6 heat-sensitive Escherichia coli dairy isolates. Production of curli and cellulose, static biofilm formation on polystyrene (PS) and stainless steel surfaces, biofilm formation under dynamic conditions (Bioflux), and initial adhesion rates (IAR) were evaluated. Biofilm formation varied greatly between strains, media, and assays. Our results highlight the importance of the experimental setup in determining biofilm formation under conditions of interest, as correlation between different assays was often not a given. The heat-resistant, multidrug-resistant (MDR) strain FAM21845 showed the strongest biofilm formation on PS and the highest IAR and was the only strain that formed significant biofilms on stainless steel under conditions relevant to the dairy industry, and it was therefore fully sequenced. Its chromosome is 4.9 Mb long, and it harbors a total of five plasmids (147.2, 54.2, 5.8, 2.5, and 1.9 kb). The strain carries a broad range of genes relevant to antimicrobial resistance and biofilm formation, including some on its two large conjugative plasmids, as demonstrated in plate mating assays. IMPORTANCE In biofilms, cells are embedded in an extracellular matrix that protects them from stresses, such as UV radiation, osmotic shock, desiccation, antibiotics, and predation. Biofilm formation is a major bacterial persistence factor of great concern in the clinic and the food industry. Many tested strains formed strong biofilms, and especially strains such as the heat-resistant, MDR strain FAM21845 may pose a serious issue for food production. Strong biofilm formation combined with diverse resistances (some encoded on conjugative plasmids) may allow for increased persistence, coselection, and possible transfer of these resistance factors. Horizontal gene transfer may conceivably occur in the food production setting or the gastrointestinal tract after consumption. PMID:28550056

  13. Cu(II) and Zn(II) adsorption capacity of three different clay liner materials.

    PubMed

    Musso, T B; Parolo, M E; Pettinari, G; Francisca, F M

    2014-12-15

    Sorption of Cu(II) and Zn(II) on three natural clays meeting the international requirements for use as liners was evaluated by means of batch tests. The purpose of this research was to determine the retention capacities of the clays for metal cations commonly present in urban solid waste leachates. The pH and ionic strength conditions were set at values frequently found in real leachates. The changes observed in the XRD patterns and FTIR spectra upon adsorption can be considered an evidence of clay-metal electrostatic interaction. The Langmuir model was found to best describe the sorption processes, offering maximum sorption capacities from 8.16 to 56.89 mg/g for Cu(II) and from 49.59 to 103.83 mg/g for Zn(II). All samples remove more Zn(II) than Cu(II), which may be related to the different geometry of the hydrated Cu(II) cation. The total amount of metal sorption was strongly influenced by the total specific surface area, the presence of carbonates and the smectite content of the clays. In addition to their known quality as physical barriers, the adsorbed amounts obtained indicate the suitability of the tested clays to contribute to the retardation of Cu(II) and Zn(II) transport through clay liners.

  14. Integrated Thermal Protection Systems and Heat Resistant Structures

    NASA Technical Reports Server (NTRS)

    Pichon, Thierry; Lacoste, Marc; Barreteau, R.; Glass, David E.

    2006-01-01

    In the early stages of NASA's Exploration Initiative, Snecma Propulsion Solide was funded under the Exploration Systems Research & Technology program to develop a CMC heatshield, a deployable decelerator, and an ablative heat shield for reentry vehicles. Due to changes within NASA's Exploration Initiative, this task was cancelled in early FY06. This paper will give an overview of the work that was accomplished prior to cancellation. The Snecma team consisted of MT Aerospace, Germany, and Materials Research & Design (MR&D), NASA Langley, NASA Dryden, and NASA Ames in the United States. An Apollo-type capsule was chosen as the reference vehicle for the work. NASA Langley generated the trajectory and aerothermal loads. Snecma and MT Aerospace began the design of a ceramic aft heatshield (CAS) utilizing C/SiC panels as the capsule heatshield. MR&D led the design of a C/SiC deployable decelerator, NASA Ames led the characterization of several ablators, NASA Dryden led the development of a heath management system and the high temperature structures testing, and NASA Langley led the insulation characterization. Though the task was pre-maturely cancelled, a significant quantity of work was accomplished.

  15. Increasing the heat resistance of vanadium by siliciding

    SciTech Connect

    Lyutyi, E.M.; Tsvikilevich, O.S.; Shirokov, V.V.; Stepanishin, V.I.

    1988-01-01

    The purpose of this article was to evaluate the influence of modifier metals on the protective properties of silicide coatings in heating of vanadium in air and also on the mechanical properties of type VnM-2 unalloyed vanadium and VTsU alloy. Coatings were produced by diffusion impregnation from molten sodium with silicon or silicides of the modifying elements. The silicides of titanium, zirconium, hafnium, niobium, tantalum, molybdenum, chromium, tungsten, rhenium, and nickel were investigated using x-ray spectrometric and hardness investigations and x-ray diffractometric analysis. The protective properties of the coatings were determined from the relative change in weight of the samples with and without coatings during isothermal oxidation in air at 1073/sup 0/K and also by differential thermal analysis. The influence of the coating on the mechanical properties of the material was also investigated using a borosilicide coating. High-temperature vacuum annealing was assessed as a method for restoring the plastic properties and relieving the stresses of vanadium and VTsU alloy subsequent to coating.

  16. Synthesis, structure, and optoelectronic properties of II-IV-V2 materials

    DOE PAGES

    Martinez, Aaron D.; Fioretti, Angela N.; Toberer, Eric S.; ...

    2017-03-07

    II-IV-V2 materials offer the promise of enhanced functionality in optoelectronic devices due to their rich ternary chemistry. In this review, we consider the potential for new optoelectronic devices based on nitride, phosphide, and arsenide II-IV-V2 materials. As ternary analogs to the III-V materials, these compounds share many of the attractive features that have made the III-Vs the basis of modern optoelectronic devices (e.g. high mobility, strong optical absorption). Control of cation order parameter in the II-IV-V2 materials can produce significant changes in optoelectronic properties at fixed chemical composition, including decoupling band gap from lattice parameter. Recent progress has begun tomore » resolve outstanding questions concerning the structure, dopability, and optical properties of the II-IV-V2 materials. Furthermore, remaining research challenges include growth optimization and integration into heterostructures and devices.« less

  17. Nanoparticles of Ni(II) and Co(II) metallo-organic molecular materials

    NASA Astrophysics Data System (ADS)

    Heras Ojea, María José; Pons Balagué, Alba; Reta Mañeru, Daniel; Carolina Sañudo, E.

    2014-01-01

    Nanoparticles of a neutral fluorescent Co(II) ferromagnet and a high nuclearity coordination Ni(II) complex have been prepared. The stability in solution of the complexes has been studied by paramagnetic proton NMR. The formation of nanoparticles from 5 to 500 nm in size, depending on the synthetic conditions, has been checked by TEM, UV-Vis and fluorescence.

  18. EFFECTS OF RADIATION ON FERROELECTRIC AND FERRIMAGNETIC MATERIALS. PART II. FERRIMAGNETIC MATERIALS

    DTIC Science & Technology

    FERRITES , *FERROELECTRIC MATERIALS, *FERROMAGNETIC MATERIALS, *FERROMAGNETISM, *GARNET, *HYSTERESIS, *MAGNETIC MATERIALS, DIELECTRICS, FAST NEUTRONS... SAMARIUM , ARTIFICIAL SATELLITES, SHIELDING, SIMULATION, SPACE ENVIRONMENTS, SPACECRAFT, YTTRIUM COMPOUNDS.

  19. Heat-resistance of Hamigera avellanea and Thermoascus crustaceus isolated from pasteurized acid products.

    PubMed

    Scaramuzza, Nicoletta; Berni, Elettra

    2014-01-03

    Products containing sugar or fruit derivatives are usually subjected to a pasteurization process that can anyway be ineffective to kill ascospores from heat-resistant molds. Although the most occurring and economically relevant heat-resistant species belong to Byssochlamys, Neosartorya, Talaromyces, and Eupenicillium genera, an increasing number of uncommon heat-resistant isolates have been recently detected as spoiling microorganisms in such products. Since Hamigera spp. and Thermoascus spp. were those more frequently isolated at SSICA, heat resistance of Hamigera avellanea and Thermoascus crustaceus strains from pasteurized acid products was studied in apple juice, in blueberry and grape juice and in a buffered glucose solution. Data obtained from thermal death curves and statistical elaboration of raw data showed that D values of H. avellanea may vary between 11.11 and 66.67 min at 87°C, between 4.67 and 13.51 at 90°C, and between 0.43 and 1.52 min at 95°C. Similarly, D values of T. crustaceus may vary between 18.52 and 90.91 min at 90°C, between 2.79 and 19.23 at 93°C, and between 1.11 and 2.53 min at 95°C. For both strains studied, the z-values calculated from the decimal reduction time curves did not prove to be significantly influenced by the heating medium, that being 4.35°C, 5.39°C or 5.27°C for H. avellanea and 4.42°C, 3.69°C or 3.37°C for T. crustaceus, respectively in apple juice, in blueberry and grape juice or in the buffered glucose solution. Considering the pasteurization treatments industrially applied to fruit-based foods, the variation of thermal parameters does not seem to be a possible way to avoid product spoilage by these two species and only good practices applied to reduce the original load of heat-resistant fungi can help producers to prevent losses in contaminated finished products, as usually happens for other heat resistant molds. © 2013 Elsevier B.V. All rights reserved.

  20. TORO II simulations of induction heating in ferromagnetic materials

    SciTech Connect

    Adkins, D.R.; Gartling, D.K.; Kelley, J.B.; Kahle, P.M.

    1997-09-01

    TORO II is a finite element computer program that is used in the simulation of electric and magnetic fields. This code, which was developed at Sandia National Laboratories, has been coupled with a finite element thermal code, COYOTE II, to predict temperature profiles in inductively heated parts. The development of an effective technique to account for the nonlinear behavior of the magnetic permeability in ferromagnetic parts is one of the more difficult aspects of solving induction heating problems. In the TORO II code, nonlinear, spatially varying magnetic permeability is approximated by an effective permeability on an element-by-element basis that effectively provides the same energy deposition that is produced when the true permeability is used. This approximation has been found to give an accurate estimate of the volumetric heating distribution in the part, and predicted temperature distributions have been experimentally verified using a medium carbon steel and a 10kW industrial induction heating unit. Work on the model was funded through a Cooperative Research and Development Agreement (CRADA) between the Department of Energy and General Motors` Delphi Saginaw Steering Systems.

  1. 46 CFR 128.220 - Class II non-vital systems-materials and pressure design.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 128.320 of this subpart, a Class II non-vital piping-system need not meet the requirements for materials and pressure design of subchapter F of this chapter. (b) Piping for salt-water service must be...

  2. Plumbing Specialist II & III, 3-22. Military Curriculum Materials for Vocational and Technical Education.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    These military-developed curriculum materials consist of a course description, course chart, plan of instruction, lesson plans, study guides, and workbooks for use in training plumbing specialists II and III. Covered in the course blocks are building waste systems and exterior and interior supply systems. Course block II, on building waste…

  3. 46 CFR 128.220 - Class II non-vital systems-materials and pressure design.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 128.320 of this subpart, a Class II non-vital piping-system need not meet the requirements for materials and pressure design of subchapter F of this chapter. (b) Piping for salt-water service must be of... schedule in wall thickness. (c) Each Class II non-vital piping-system must be certified by the builder as...

  4. 46 CFR 128.220 - Class II non-vital systems-materials and pressure design.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 128.320 of this subpart, a Class II non-vital piping-system need not meet the requirements for materials and pressure design of subchapter F of this chapter. (b) Piping for salt-water service must be of... schedule in wall thickness. (c) Each Class II non-vital piping-system must be certified by the builder as...

  5. Influence of pH on heat resistance of spores of Bacillus coagulans in buffer and homogenized foods.

    PubMed

    Palop, A; Raso, J; Pagán, R; Condón, S; Sala, F J

    1999-02-18

    The influence of pH of heating menstruum (McIlvaine buffer) on the heat resistance of Bacillus coagulans spores has been investigated and compared with the heat resistance in homogenized tomato and asparagus at pH 7 and 4 at a wide range of temperatures. Spores were less heat resistant in all menstrua at acid pH. The magnitude of this effect was greatest at the lowest heating temperatures tested. z values in buffer increased from 8.9 degrees C at pH 7 to 10.5 degrees C at pH 4. pH of menstrua was the main influencing factor, but media composition also influenced heat resistance: at pH 7 heat resistance was similar in all menstrua (D111 degrees C = 1.6 min) but at pH 4 the heat resistance in homogenized foods (D111 degrees C = 0.26 min in tomato and D111 degrees C = 0.28 min in asparagus) was lower than in buffer (D111 degrees C = 0.49 min). The reduced influence of the acidification of media on the heat resistance of B. coagulans at higher temperatures should be taken into account when a rise in the temperature of treatment for canned vegetables is considered to shorten duration of heat processes.

  6. [Possible pathways of heat resistance induction in plant cells by exogenous nitrogen oxide].

    PubMed

    Karpets, Iu V; Kolupaev, Iu E; Iastreb, T O; Dmitriev, A P

    2012-01-01

    The mechanisms of influence of exogenous nitrogen oxide (NO) on heat resistance of wheat coleoptiles have been studied. The treatment of plant cells with nitrogen oxide donor (sodium nitroprusside) resulted in the increase of superoxide anion-radical (O2*-) generation already after 10 minutes. The inhibitor of protein biosynthesis cycloheximide did not inhibit the O2*- generation by coleoptiles caused with the NO donor whereas the inhibitor of phosphatidic acid formation (butanol-1) partially inhibited it. The treatment of coleoptiles with the calcium ionophore (A23187) or activator of inositol cycle (inositol) compensated the suppression of butanol-1 effect on NO-dependent O2*- formation. Butanol-1 has also leveled the induction of coleoptiles heat resistance caused by the NO donor, whereas calcium ionophore and inositol almost completely removed the butanol-1 effect. The possible mechanisms of participation of reactive oxygen species, phosphatidic acid and calcium ions in the realization of NO physiological effects are discussed.

  7. Enhanced microwave absorbing properties and heat resistance of carbonyl iron by electroless plating Co

    NASA Astrophysics Data System (ADS)

    Wang, Hongyu; Zhu, Dongmei; Zhou, Wancheng; Luo, Fa

    2015-11-01

    Co coated carbonyl iron particles (Co (CI)) are fabricated through electroless plating method, and the electromagnetic microwave absorbing properties are investigated in the frequencies during 8.2-12.4 GHz. The complex permittivity of CI particles after electroless plating Co is higher than that of raw CI particles due to improvment of the polarization process. Furthermore, according to the XRD and TG results, the Co layer can enhance the heat resistance of CI particles. The bandwidth below -10 dB can reach 3.9 GHz for the Co(CI) absorbent. The results indicate that the electroless plating Co not only enhances the absorbing properties but also improves the heat resistance of CI.

  8. Incidence of heat-resistant molds in eastern orchards and vineyards.

    PubMed

    Splittstoesser, D F; Kuss, F R; Harrison, W; Prest, D B

    1971-02-01

    Over 70% of the samples of fruit, vegetation, and soil obtained in surveys of New York orchards and vineyards were contaminated with heat-resistant molds. The counts generally were low, under one per gram. Byssochlamys fulva was the most common isolate. Other isolates were identified as B. nivea, Paecilomyces varioti, Aspergillus fischeri, A. fischeri var. spinosus, A. fumigatus, Penicillium vermiculatum, and P. ochro-chloron.

  9. Incidence and Diversity of Potentially Highly Heat-Resistant Spores Isolated at Dairy Farms

    PubMed Central

    Scheldeman, Patsy; Pil, Annelies; Herman, Lieve; De Vos, Paul; Heyndrickx, Marc

    2005-01-01

    The presence of highly heat-resistant spores of Bacillus sporothermodurans in ultrahigh-temperature or sterilized consumer milk has emerged as an important item in the dairy industry. Their presence is considered undesirable since they hamper the achievement of commercial sterility requirements. By using a selective 30-min heat treatment at 100°C, 17 Belgian dairy farms were screened to evaluate the presence, sources, and nature of potentially highly heat-resistant spores in raw milk. High numbers of these spores were detected in the filter cloth of the milking equipment and in green crop and fodder samples. About 700 strains were isolated after the selective heating, of which 635 could be screened by fatty acid methyl ester analysis. Representative strains were subjected to amplified ribosomal DNA restriction analysis, 16S rRNA gene sequencing, percent G+C content, and DNA-DNA reassociations for further identification. The strain collection showed a remarkable diversity, with representatives of seven aerobic spore-forming genera. Bacillus licheniformis and Bacillus pallidus were the most predominant species overall. Twenty-three percent of the 603 spore-forming isolates proved to belong to 18 separate novel species. These findings suggest that the selective heating revealed a pool of unknown organisms with a higher heat-resistant character. This study showed that high spore counts can occur at the dairy farm and that feed and milking equipment can act as reservoirs or entry points for potentially highly heat-resistant spores into raw milk. Lowering this spore load by good hygienic measures could probably further reduce the contamination level of raw milk, in this way minimizing the aerobic spore-forming bacteria that could lead to spoilage of milk and dairy products. Assessment and characterization of this particular flora are of great importance to allow the dairy or food industry to adequately deal with newly arising microbiological problems. PMID:15746351

  10. Incidence of Heat-Resistant Molds in Eastern Orchards and Vineyards 1

    PubMed Central

    Splittstoesser, D. F.; Kuss, F. R.; Harrison, Wanda; Prest, Dorothy B.

    1971-01-01

    Over 70% of the samples of fruit, vegetation, and soil obtained in surveys of New York orchards and vineyards were contaminated with heat-resistant molds. The counts generally were low, under one per gram. Byssochlamys fulva was the most common isolate. Other isolates were identified as B. nivea, Paecilomyces varioti, Aspergillus fischeri, A. fischeri var. spinosus, A. fumigatus, Penicillium vermiculatum, and P. ochro-chloron. PMID:5544294

  11. Dependence of heat resistance of Drosophila on ambient temperature and relationship of this property to mutation process

    SciTech Connect

    Tikhomirova, M.M.; Belyatskaya, O.Ya.

    1986-04-01

    It has been demonstrated that thermosensitvity of the gametes in Drosophila line T correlates with the heat resistance of the flies. This property of the gametes is determined during ontogenesis, depending on the temperature during development and not by genotypic preadaptation as such, i.e., affinity of the females to the heat resistance line T. The ability of females to acquire heat resistance during the adult phase (in the first three days after emergence), i.e., by acclimatization to a temperature different from the temperature during development does not change the response of the gametes to extreme temperature which had developed during ontogenesis under a particular temperature.

  12. Heat resistance of Listeria monocytogenes in vacuum packaged pasteurized fish fillets.

    PubMed

    Ben Embarek, P K; Huss, H H

    1993-11-01

    The heat resistance of two strains of Listeria monocytogenes in sous-vide cooked fillets of cod and salmon was investigated. Fish sticks of 5 g were inoculated, vacuum-packed and heated at different combinations of time and temperature (58-80 degrees C). Time-temperature combinations allowing survival and time-temperature combinations at which the bacteria were destroyed, were used to determine D- and z-values. D-values were in the range of what has been published for other food products. D60-values were between 1.95 and 4.48 min depending on the strain and the fish. Both strains were one-four-times more heat resistant in salmon than in cod, showing the importance of the heating menstruum. This difference may be due to the higher fat content in salmon as compared to cod. Z-values were calculated to be 5.65 and 6.4 degrees C, respectively, for the two strains. The suitability of methods for heat resistance experiments and the survival of L. monocytogenes in sous-vide cooked fish fillets are discussed.

  13. Heat Resistant Characteristics of Major Royal Jelly Protein 1 (MRJP1) Oligomer.

    PubMed

    Moriyama, Takanori; Ito, Aimi; Omote, Sumire; Miura, Yuri; Tsumoto, Hiroki

    2015-01-01

    Soluble royal jelly protein is a candidate factor responsible for mammiferous cell proliferation. Major royal jelly protein 1 (MRJP1), which consists of oligomeric and monomeric forms, is an abundant proliferative protein in royal jelly. We previously reported that MRJP1 oligomer has biochemical heat resistance. Therefore, in the present study, we investigated the effects of several heat treatments (56, 65 and 96°C) on the proliferative activity of MRJP1 oligomer. Heat resistance studies showed that the oligomer molecular forms were slightly maintained until 56℃, but the molecular forms were converted to macromolecular heat-aggregated MRJP1 oligomer at 65℃ and 96℃. But, the growth activity of MRJP1 oligomer treated with 96°C was slightly attenuated when compared to unheated MRJP1 oligomer. On the other hand, the cell proliferation activity was preserved until 96℃ by the cell culture analysis of Jurkat cells. In contrast, those of IEC-6 cells were not preserved even at 56°C. The present observations suggest that the bioactive heat-resistance properties were different by the origin of the cells. The cell proliferation analysis showed that MRJP1 oligomer, but not MRJP2 and MRJP3, significantly increased cell numbers, suggesting that MRJP1 oligomer is the predominant proliferation factor for mammiferous cells.

  14. Bark heat resistance of small trees in Californian mixed conifer forests: Testing some model assumptions

    USGS Publications Warehouse

    van Mantgem, Phillip J.; Schwartz, Mark

    2003-01-01

    An essential component to models of fire-caused tree mortality is an assessment of cambial damage. Cambial heat resistance has been traditionally measured in large overstory trees with thick bark, although small trees have thinner bark and thus are more sensitive to fire. We undertook this study to determine if current models of bark heat transfer are applicable to small trees (<20 cm diameter at breast height (dbh)). We performed this work in situ on four common species in the mixed conifer forests of the Sierra Nevada, California.The allometric relationship between bole diameter and bark thickness for each species was linear, even for very small trees (5 cm dbh). Heating experiments demonstrated that bark thickness was the primary determinant of cambial heat resistance. We found only slight, but statistically significant, among species differences in bark thermal properties. Our most significant finding was that small trees were more resistant to heating than expected from commonly used models of bark heat transfer. Our results may differ from those of existing models because we found smaller trees to have a greater proportion of inner bark, which appears to have superior insulating properties compared to outer bark. From a management perspective, growth projections suggest that a 50-year fire-free interval may allow some fire intolerant species to achieve at least some degree of cambial heat resistance in the Sierra Nevada.

  15. SIGNAL MEDIATORS AT INDUCTION OF HEAT RESISTANCE OF WHEAT PLANTLETS BY SHORT-TERM HEATING.

    PubMed

    Karpets, Yu V; Kolupaev, Yu E; Yastreb, T O

    2015-01-01

    The effects of functional interplay of calcium ions, reactive oxygen species (ROS) and nitric oxide (NO) in the cells of wheat plantlets roots (Triticum aestivum L.) at the induction of their heat resistance by a short-term influence of hyperthermia (heating at the temperature of 42 degrees C during 1 minute) have been investigated. The transitional increase of NO and H2O2 content, invoked by heating, was suppressed by the treatment of plantlets with the antagonists of calcium EGTA (chelator of exocellular calcium), lanthanum chloride (blocker of calcium channels of various types) and neomycin (inhibitor of phosphatidylinositol-dependent phospholipase C). The rise of hydrogen peroxide content, caused by hardening, was partially suppressed by the action of inhibitors of nitrate reductase (sodium wolframate) and NO-synthase (N(G)-nitro-L-arginine methyl ester--L-NAME), and the increasing of nitric oxide content was suppressed by the treatment of plants with the antioxidant ionol and with the scavenger of hydrogen peroxide (dimethylthiourea). These compounds and antagonists of calcium also partially removed the effect of the rise of plantlets' heat resistance, invoked by hardening heating. The conclusion on calcium's role in the activation of enzymatic systems, generating reactive oxygen species and nitric oxide, and on the functional interplay of these signal mediators at the induction of heat resistance of plantlets by hardening heating is made.

  16. Two distinct groups within the Bacillus subtilis group display significantly different spore heat resistance properties.

    PubMed

    Berendsen, Erwin M; Zwietering, Marcel H; Kuipers, Oscar P; Wells-Bennik, Marjon H J

    2015-02-01

    The survival of bacterial spores after heat treatment and the subsequent germination and outgrowth in a food product can lead to spoilage of the food product and economical losses. Prediction of time-temperature conditions that lead to sufficient inactivation requires access to detailed spore thermal inactivation kinetics of relevant model strains. In this study, the thermal inactivation kinetics of spores of fourteen strains belonging to the Bacillus subtilis group were determined in detail, using both batch heating in capillary tubes and continuous flow heating in a micro heater. The inactivation data were fitted using a log linear model. Based on the spore heat resistance data, two distinct groups (p < 0.001) within the B. subtilis group could be identified. One group of strains had spores with an average D120 °C of 0.33 s, while the spores of the other group displayed significantly higher heat resistances, with an average D120 °C of 45.7 s. When comparing spore inactivation data obtained using batch- and continuous flow heating, the z-values were significantly different, hence extrapolation from one system to the other was not justified. This study clearly shows that heat resistances of spores from different strains in the B. subtilis group can vary greatly. Strains can be separated into two groups, to which different spore heat inactivation kinetics apply.

  17. Heat Resistant Characteristics of Major Royal Jelly Protein 1 (MRJP1) Oligomer

    PubMed Central

    Moriyama, Takanori; Ito, Aimi; Omote, Sumire; Miura, Yuri; Tsumoto, Hiroki

    2015-01-01

    Soluble royal jelly protein is a candidate factor responsible for mammiferous cell proliferation. Major royal jelly protein 1 (MRJP1), which consists of oligomeric and monomeric forms, is an abundant proliferative protein in royal jelly. We previously reported that MRJP1 oligomer has biochemical heat resistance. Therefore, in the present study, we investigated the effects of several heat treatments (56, 65 and 96°C) on the proliferative activity of MRJP1 oligomer. Heat resistance studies showed that the oligomer molecular forms were slightly maintained until 56℃, but the molecular forms were converted to macromolecular heat-aggregated MRJP1 oligomer at 65℃ and 96℃. But, the growth activity of MRJP1 oligomer treated with 96°C was slightly attenuated when compared to unheated MRJP1 oligomer. On the other hand, the cell proliferation activity was preserved until 96℃ by the cell culture analysis of Jurkat cells. In contrast, those of IEC-6 cells were not preserved even at 56°C. The present observations suggest that the bioactive heat-resistance properties were different by the origin of the cells. The cell proliferation analysis showed that MRJP1 oligomer, but not MRJP2 and MRJP3, significantly increased cell numbers, suggesting that MRJP1 oligomer is the predominant proliferation factor for mammiferous cells. PMID:26020775

  18. Porphyrin photosensitivity in cell lines expressing a heat-resistant phenotype

    NASA Astrophysics Data System (ADS)

    Gomer, Charles J.; Rucker, Natalie; Wong, Sam

    1990-07-01

    In-vitro sensitivity to porphyrin mediated photodynamic therapy (PDT) has been examined in cell lines resistant to hyperthermia. Parental (HA-i) and heat resistant (3012) Chinese hamster fibroblasts as well as parental (RIF-i) and temperature resistant (TR-4, TR-5 and TR-iO) mouse radiation-induced fibrosarcoma cells were evaluated for thermal and PDT sensitivity. Quantitative survival curves were generated and porphyrin uptake properties were obtained for all cell lines. Significant resistance to hyperthermia (450C for varying exposure periods) was documented for the 3012 and TR cell strains when compared to 'the parent lines. However, normal and heat resistant clones exhibited comparable levels of porphyrin uptake and photosensitivity. Our results indicate that cross resistance between hyperthermia and PDT is not observed and that members of the 70 kD heat shock protein family (which are elevated in the thermal resistant cells and may be associated with the heat resistant phenotype) do not play a significant role in modulating PDT sensitivity. Mechanisms of in-vitro cytotoxicity appear to be different for PDT and hyperthermia even though possible subcellular targets (such as the plasma membrane) and types of damage (protein denaturation) may be similar for the two modalities.

  19. Agni's fungi: heat-resistant spores from the Western Ghats, southern India.

    PubMed

    Suryanarayanan, T S; Govindarajulu, M B; Thirumalai, E; Reddy, M Sudhakara; Money, Nicholas P

    2011-09-01

    This study concerns the thermotolerance of spores of mesophilic fungi isolated from a tropical semi-arid habitat subject to dry season fire in the Western Ghats, southern India. Among 25 species of Ascomycota isolated from leaf litter, nine were able to grow after incubation in a drying oven for 2h at 100°C; the spores of two of these species survived 2h incubation at 110°C, and one survived exposure to 115°C for 2h. The range of thermotolerance among mesophilic fungi isolated from the leaf litter was surprising: filamentous fungi from other habitats, including species that colonize scorched vegetation after fires and thermophilic forms occurring in self-heating plant composts, cannot survive even brief exposure to such high temperatures. It is possible that the exceptional heat resistance of the Indian fungi is related to adaptations to surviving fires. Genetic analysis of the physiological mechanisms of heat resistance in these fungi offers prospects for future biotechnological innovations. The discovery of extreme thermotolerance among common saprotrophs shows that this physiological trait may be more widespread than recognized previously, adding to concern about the evolution of opportunistic pathogens on a warmer planet. The fungi in this study are among the most heat-resistant eukaryotes on record and are referred to here as 'Agni's Fungi', after the Hindu God of Fire. Copyright © 2011 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  20. Unifying Type II Supernova Light Curves with Dense Circumstellar Material

    NASA Astrophysics Data System (ADS)

    Morozova, Viktoriya; Piro, Anthony L.; Valenti, Stefano

    2017-03-01

    A longstanding problem in the study of supernovae (SNe) has been the relationship between the Type IIP and Type IIL subclasses. Whether they come from distinct progenitors or they are from similar stars with some property that smoothly transitions from one class to another has been the subject of much debate. Here, using one-dimensional radiation-hydrodynamic SN models, we show that the multi-band light curves of SNe IIL are well fit by ordinary red supergiants surrounded by dense circumstellar material (CSM). The inferred extent of this material, coupled with a typical wind velocity of ∼ 10{--}100 {km} {{{s}}}-1, suggests enhanced activity by these stars during the last ~months to ∼years of their lives, which may be connected with advanced stages of nuclear burning. Furthermore, we find that, even for more plateau-like SNe, dense CSM provides a better fit to the first ∼ 20 days of their light curves, indicating that the presence of such material may be more widespread than previously appreciated. Here we choose to model the CSM with a wind-like density profile, but it is unclear whether this just generally represents some other mass distribution, such as a recent mass ejection, thick disk, or even inflated envelope material. Better understanding the exact geometry and density distribution of this material will be an important question for future studies.

  1. Type-II nodal loops: Theory and material realization

    NASA Astrophysics Data System (ADS)

    Li, Si; Yu, Zhi-Ming; Liu, Ying; Guan, Shan; Wang, Shan-Shan; Zhang, Xiaoming; Yao, Yugui; Yang, Shengyuan A.

    2017-08-01

    A nodal loop appears when two bands, typically one electronlike and one holelike, are crossing each other linearly along a one-dimensional manifold in reciprocal space. Here, we propose a type of nodal loop which emerges from the crossing between two bands which are both electronlike (or holelike) along a certain direction. Close to any point on such a loop (dubbed as a type-II nodal loop), the linear spectrum is strongly tilted and tipped over along one transverse direction, leading to marked differences in magnetic, optical, and transport responses compared with conventional (type-I) nodal loops. We show that the compound K4P3 is an example that hosts a pair of type-II nodal loops close to the Fermi level. Each loop traverses the whole Brillouin zone, and hence can only be annihilated in a pair when symmetry is preserved. The symmetry and topological protections of the loops as well as the associated surface states are discussed.

  2. Fair Play. A Bibliography of Nonstereotyped Materials. Volume II.

    ERIC Educational Resources Information Center

    Hulme, Marylin A., Comp.

    This resource bibliography lists and very briefly annotates non-sexist and non-racist printed materials (books, pamphlets, games and kits) suitable for elementary through secondary school rooms. Works are cited by level (K-3, 4-6, 7-9, 10-12 and teacher resources), and then subdivided into subject areas, with entries arranged alphabetically by…

  3. Centrifuge Crater Scaling Experiment II. Material Strength Effects

    DTIC Science & Technology

    1979-05-01

    materials; whereas for hypervelocity impact into water, Gault (1978) obtained cratering data that approaches quarter- root scaling--1/3.83. A second...either the explosive size or gravity is increased. For example, Nr!Kinnon and Melosh (1978) have shown for craters with vertical walls and flat...flatter crater ). It also has the largest value of the stability parameter, which probably acccunts for its unique flat profile. McKinnon and Melosh

  4. 10 CFR 76.115 - Special nuclear material of moderate strategic significance-Category II.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Special nuclear material of moderate strategic significance-Category II. 76.115 Section 76.115 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safeguards and Security § 76.115 Special nuclear material of...

  5. 46 CFR 128.210 - Class II vital systems-materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Class II vital systems-materials. 128.210 Section 128.210 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS MARINE... Commanding Officer, Marine Safety Center, if shown to provide a level of safety equivalent to materials...

  6. 10 CFR 76.115 - Special nuclear material of moderate strategic significance-Category II.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 2 2013-01-01 2013-01-01 false Special nuclear material of moderate strategic significance-Category II. 76.115 Section 76.115 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safeguards and Security § 76.115 Special nuclear material of moderate...

  7. 10 CFR 76.115 - Special nuclear material of moderate strategic significance-Category II.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 2 2014-01-01 2014-01-01 false Special nuclear material of moderate strategic significance-Category II. 76.115 Section 76.115 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safeguards and Security § 76.115 Special nuclear material of moderate...

  8. 10 CFR 76.115 - Special nuclear material of moderate strategic significance-Category II.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 2 2011-01-01 2011-01-01 false Special nuclear material of moderate strategic significance-Category II. 76.115 Section 76.115 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safeguards and Security § 76.115 Special nuclear material of moderate...

  9. 10 CFR 76.115 - Special nuclear material of moderate strategic significance-Category II.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 2 2012-01-01 2012-01-01 false Special nuclear material of moderate strategic significance-Category II. 76.115 Section 76.115 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safeguards and Security § 76.115 Special nuclear material of moderate...

  10. Draft Genome Sequences of 10 Bacillus subtilis Strains That Form Spores with High or Low Heat Resistance

    PubMed Central

    Berendsen, Erwin M.; Wells-Bennik, Marjon H. J.; Krawczyk, Antonina O.; de Jong, Anne; van Heel, Auke; Eijlander, Robyn T.

    2016-01-01

    Here, we report the draft genome sequences of 10 isolates of Bacillus subtilis, a spore forming Gram-positive bacterium. The strains were selected from food products and produced spores with either high or low heat resistance. PMID:26988043

  11. Aspergilli with Neosartorya-type ascospores: heat resistance and effect of sugar concentration on growth and spoilage incidence in berry products.

    PubMed

    Berni, Elettra; Tranquillini, Roberta; Scaramuzza, Nicoletta; Brutti, Andrea; Bernini, Valentina

    2017-10-03

    This study focused on four different heat resistant aspergilli: two strains of Aspergillus hiratsukae (≡Neosartorya hiratsukae), one strain of Aspergillus neoglaber (≡Neosartorya glabra), and one strain of Aspergillus thermomutatus (≡Neosartorya pseudofischeri), all isolated from spoiled pasteurized products. Their heat-resistance, the sugar concentration limiting their germination and growth in berry-based media, and a possible relation between the contamination levels of the raw materials used and the spoilage incidence in strawberry jams were assessed. Heat resistance data obtained from thermal death curves showed that the D values of the strains tested ranged between 3.7 and 13.5min at 87°C; 1.5 and 3.5min at 90°C; and 0.3 and 0.4min at 95°C in glucose solution. Similarly, D values ranged between 3.3 and 15.4min at 87°C; 1.3 and 4.3min at 90°C; and 0.3 and 0.6min at 95°C in strawberry-based formulation. For all strains, the corresponding z-values ranged between 5.7 and 8.3°C in glucose solution and from 5.7 to 8.4°C in strawberry formulation. With regard to the limitation of fungal germination and growth in fruit-based media, sucrose concentrations required to avoid growth varied between 45.0 and 55.0% for strawberry medium and between 42.5% and 50.0% for blueberry medium. Spore inactivation was observed below aw 0.88-0.91 for strawberries and aw 0.87-0.90 for blueberries; above 49.7-56.5°Bx for strawberries and 49.6-56.0°Bx for blueberries. The threshold optical refractometric residue proved strain-dependent, but substrate-independent, as for each strain the highest Brix degree value at which germination occurred was the same on both media, despite their different sucrose concentrations. With regard to the relation between contamination of raw materials by heat-resistant mould spores and spoilage incidence on final product, an equation was modelled to estimate the occurrence of fungal spoilage in strawberry jams for low contamination levels (26

  12. Organoapatites: materials for artificial bone. II. Hardening reactions and properties.

    PubMed

    Stupp, S I; Mejicano, G C; Hanson, J A

    1993-03-01

    This article reports on chemical reactions and the properties they generated in artificial bone materials termed "organoapatites." These materials are synthesized using methodology we reported in the previous article of this series. Two different processes were studied here for the transition from organoapatite particles to implants suitable for the restoration of the skeletal system. One process involved the hardening of powder compacts by beams of blue light derived from a lamp or a laser and the other involved pressure-induced interdiffusion of polymers. In both cases, the hardening reaction involved the formation of a polyion complex between two polyelectrolytes. In the photo-induced reaction an anionic electrolyte polymerizes to form the coulombic network and in the pressure-induced one, pressure forms the complex by interdiffusion of two polyions. Model reactions were studied using various polycations. Based on these results the organoapatite selected for the study was that containing dispersed poly(L-lysine) and sodium acrylate as the anionic monomer. The organomineral particles can be pressed at room temperature into objects of great physical integrity and hydrolytic stability relative to anorganic controls. The remarkable fact about these objects is that intimate molecular dispersion of only 2-3% by weight organic material provides integrity to the mineral network in an aqueous medium and also doubles its tensile strength. This integrity is essentially nonexistent in "anorganic" samples prepared by the same methodology used in organoapatite synthesis. The improvement in properties was most effectively produced by molecular bridges formed by photopolymerization. The photopolymerization leads to the "hardening" of pellets prepared by pressing of organoapatite powders. The reaction was found to be more facile in the microstructure of the organomineral, and it is potentially useful in the surgical application of organoapatites as artificial bone.

  13. The effect of lime-dried sewage sludge on the heat-resistance of eco-cement.

    PubMed

    Li, Wen-Quan; Liu, Wei; Cao, Hai-Hua; Xu, Jing-Cheng; Liu, Jia; Li, Guang-Ming; Huang, Juwen

    2016-01-01

    The treatment and disposal of sewage sludge is a growing problem for sewage treatment plants. One method of disposal is to use sewage sludge as partial replacement for raw material in cement manufacture. Although this process has been well researched, little attention has been given to the thermal properties of cement that has had sewage sludge incorporated in the manufacturing process. This study investigated the fire endurance of eco-cement to which lime-dried sludge (LDS) had been added. LDS was added in proportions of 0%, 3%, 6%, 9%, and 12% (by weight) to the raw material. The eco-cement was exposed to 200, 400, or 600 °C for 3 h. The residual strength and the microstructural properties of eco-cement were then studied. Results showed that the eco-cement samples suffered less damage than conventional cement at 600 °C. The microstructural studies showed that LDS incorporation could reduce Ca(OH)(2) content. It was concluded that LDS has the potential to improve the heat resistance of eco-cement products.

  14. Optimization and characterization of poly(phthalazinone ether ketone) (PPEK) heat-resistant porous fiberous mat by electrospinning

    NASA Astrophysics Data System (ADS)

    Shi, R.; Bin, Y. Z.; Yang, W. X.; Wang, D.; Wang, J. Y.; Jian, X. G.

    2016-08-01

    Poly(phthalazinone ether ketone) (PPEK) is noted for its outstanding heat-resistance property and mechanical strength. A one-step electrospinning method was conducted to produce PPEK micro-nano porous fibrous mat. We gave emphasis study on the spinnability, optimized conditions, fibers' morphology, surface science and fracture mechanism. The uniform electrospun fibrous mat resulted from PPEK/chloroform binary system indicated that PPEK would be a prospective material to be applied in electrospinning. Addition of a small amount of non-solvent (ethanol) turned out to be advantageous to the reduction of fiber diameter and the alleviation of choking during spinning process. Organic salt (benzyltrimethylammonium chloride) was employed to increase the conductivity of solution for the formation of thin fiber. After trials, PPEK/chloroform/ethanol system with salt and PPEK/NMP system were taken as two optimized systems. These two systems showed different pore fraction in N2 adsorption test, and displayed different mechanical behaviors in uniaxial tension test. The fibrous mat from PPEK/chloroform/ethanol system showed a feature of ductile fracture with relatively low fracture strength but long fracture deformation, while the fibrous mat from PPEK/NMP system showed a feature of brittle fracture with small deformation but quite large fracture strength of ca. 6 MPa. Finally thermogravimetric analysis indicated that the resultant PPEK fibrous mat did not decompose until the temperature reached 478 °C, which qualified the resultant fibrous mat as a promising material used under high-temperature condition.

  15. Modeling heat resistance of Bacillus weihenstephanensis and Bacillus licheniformis spores as function of sporulation temperature and pH.

    PubMed

    Baril, Eugénie; Coroller, Louis; Couvert, Olivier; Leguérinel, Ivan; Postollec, Florence; Boulais, Christophe; Carlin, Frédéric; Mafart, Pierre

    2012-05-01

    Although sporulation environmental factors are known to impact on Bacillus spore heat resistance, they are not integrated into predictive models used to calculate the efficiency of heating processes. This work reports the influence of temperature and pH encountered during sporulation on heat resistance of Bacillus weihenstephanensis KBAB4 and Bacillus licheniformis AD978 spores. A decrease in heat resistance (δ) was observed for spores produced either at low temperature, at high temperature or at acidic pH. Sporulation temperature and pH maximizing the spore heat resistance were identified. Heat sensitivity (z) was not modified whatever the sporulation environmental factors were. A resistance secondary model inspired by the Rosso model was proposed. Sporulation temperatures and pHs minimizing or maximizing the spore heat resistance (T(min(R)), T(opt(R)), T(max(R)), pH(min(R)) and pH(opt(R))) were estimated. The goodness of the model fit was assessed for both studied strains and literature data. The estimation of the sporulation temperature and pH maximizing the spore heat resistance is of great interest to produce spores assessing the spore inactivation in the heating processes applied by the food industry. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Does increased heat resistance result in higher susceptibility to predation? A test using Drosophila melanogaster selection and hardening.

    PubMed

    Hangartner, Sandra; Dworkin, Ian; DeNieu, Michael; Hoffmann, Ary A

    2017-04-07

    Heat resistance of ectotherms can be increased both by plasticity and evolution, but these effects may have trade-offs resulting from biotic interactions. Here we test for predation costs in Drosophila melanogaster populations with altered heat resistance produced by adult hardening and directional selection for increased heat resistance. In addition, we also tested for genetic trade-offs by testing heat resistance in lines that have evolved under increased predation risk. We show that while 35/37°C hardening increases heat resistance as expected, it does not increase predation risk from jumping spiders or mantids; in fact there was an indication that survival may have increased under predation following a triple 37°C compared to a single 35°C hardening treatment. Flies that survived a 39°C selection cycle showed lower survival under predation, suggesting a predation cost of exposure to a more severe heat stress. There was however no correlated response to selection because survival did not differ between control and selected lines after selection was relaxed for one or two generations. In addition, lines selected for increased predation risk did not differ in heat resistance. Our findings suggest independent evolutionary responses to predation and heat as measured in laboratory assays, and no costs of heat hardening on susceptibility to predation. This article is protected by copyright. All rights reserved.

  17. Experimental investigations of the influence of material and thickness on fracture under pure mode II loading

    NASA Astrophysics Data System (ADS)

    Dong, H.

    2010-06-01

    Experimental investigation to the effects of thickness and material on mode II fracture were performed. Tension-shear specimens made of aluminium alloy LC4CS and 7050-T7452 with thicknesses of 2, 4, 8 and 14 mm were used. All crack tip appearances and fracture profiles of the specimens were observed. Mode II fracture toughness were calculated. It is shown that material and thickness play an important role in mode II fracture. The fracture of LC4CS appears shear fracture under all kinds of thicknesses, however the fracture of 7050-T7452 is tensile fracture when thickness is larger or equal to 8mm, and shear initiation along the original crack plane, then turnaround and tensile failure when thickness is smaller than 8mm. Mode II fracture toughness is independent of thickness.

  18. Tungsten alloyed with rhenium as an advanced material for heat-resistant silicon ICs interconnects

    NASA Astrophysics Data System (ADS)

    Belov, A. N.; Chaplygin, Yu. A.; Golishnikov, A. A.; Kostyukov, D. A.; Putrya, M. G.; Safonov, S. O.; Shevyakov, V. I.

    2016-12-01

    This paper presents the results of comparative analysis of the electrical and mechanical characteristics of the tungsten and tungsten alloyed with rhenium films deposited on silicon, from the point of view of their use as interconnects in silicon ICs. W and W (Re-5%) alloyed with rhenium films were made by magnetron deposition. Sheet resistivity for W and W (Re- 5%) was 13 and 27 μOhm·cm respectively. Elemental composition the formed films was examined by Auger spectroscopy. To investigate the electromigration resistance of the conductors a methodology based on the accelerated electromigration testing at constant temperature was used. A comparative analysis of the mechanical stresses carried out in the W and W(Re - 5%) films. For this purpose was applied non-destructive method for optical laser scanning. At the same time, these films explored their ability of adhesion to silicon and silicon oxide. It is shown that the pull force of the W(Re - 5%) films was 1500 G/mm2, of the W films 700 G/mm2

  19. Characterization of a wild strain of Alicyclobacillus acidoterrestris: heat resistance and implications for tomato juice.

    PubMed

    Bevilacqua, Antonio; Corbo, Maria R

    2011-03-01

    This article reports the characterization of a wild strain of Alicyclobacillus acidoterrestris and describes the implications of the heat resistance of this microorganism in tomato juice. The strain (labeled as A. acidoterrestrisγ4) showed pH and temperature ranges for growth typical of the species (3.0 to 6.0 for the pH and 35 to 60 °C for the temperature); heat resistance in tomato juice was as follows: D(T) values of 40.65, 9.47, and 1.5 min (at 85, 90, and 95 °C, respectively) and z-value of 7 °C. A treatment at 70 °C for 15 min was found to be optimal for spore activation, whereas Malt Extract Agar, acidified to pH 4.5, showed good results for spore recovery. Concerning the implications of heat resistance of A. acidoterrestris on tomato juice, high temperatures required for spore inactivation determined a general decrease of the antioxidant activity (increase of the redox potential and reduction of the chain-breaking activity), but not the formation of brown compounds (namely, hydroxymethylfurfural), thus suggesting an effect on the secondary antioxidants (carotenoids and ascorbic acid) rather than on lycopene. Alicyclobacillus acidoterrestris is an emerging spore-forming microorganism, capable of causing spoilage in tomato juice. Due to their high thermal resistance, spores could be used as targets for the optimization of heat processing; this article reports on the assessment of thermal resistance of a wild strain of A. acidoterrestris, then focusing on the effect of the thermal treatment necessary to inactivate spores on the quality of tomato juice.

  20. Effect of aluminizing treatment on the oxidation properties of 12Cr heat resisting steel

    NASA Astrophysics Data System (ADS)

    Kim, Jae-Hwan; Wang, Jei-Pil; Kang, Chang-Yong

    2011-12-01

    In order to investigate the effect of aluminization on the oxidation properties of 12Cr martensitic heat resisting steel, a specimen was prepared by forging after centrifugal casting. After aluminizing treatment under various conditions, scanning electron microscopy observation, and hardness, line profile and x-ray diffraction analysis of the alloy layer were performed. The results confirmed that the thickness of the layer of Al13Fe4, with a Vickers hardness of over 880, increased with increasing aluminizing temperature and time. Moreover, it was concluded from the results of the oxidation experiment that the oxidation properties of the aluminized specimen were improved by up to approximately 30 %.

  1. Boron and Zirconium from Crucible Refractories in a Complex Heat-Resistant Alloy

    NASA Technical Reports Server (NTRS)

    Decker, R F; Rowe, John P; Freeman, J W

    1958-01-01

    In a laboratory study of the factors involved in the influence of induction vacuum melting on 55ni-20cr-15co-4mo-3ti-3al heat resistant alloy, it was found that the major factor was the type of ceramic used as the crucible. The study concluded that trace amounts of boron or zirconium derived from reaction of the melt with the crucible refactories improved creep-rupture properties at 1,600 degrees F. Boron was most effective and, in addition, markedly improved hot-workability.

  2. Mode II Interlaminar Fracture Toughness and Fatigue Characterization of a Graphite Epoxy Composite Material

    NASA Technical Reports Server (NTRS)

    O'Brien, T. Kevin; Johnston, William M.; Toland, Gregory J.

    2010-01-01

    Mode II interlaminar fracture toughness and delamination onset and growth characterization data were generated for IM7/8552 graphite epoxy composite materials from two suppliers for use in fracture mechanics analyses. Both the fracture toughness testing and the fatigue testing were conducted using the End-notched Flexure (ENF) test. The ENF test for mode II fracture toughness is currently under review by ASTM as a potential standard test method. This current draft ASTM protocol was used as a guide to conduct the tests on the IM7/8552 material. This report summarizes the test approach, methods, procedures and results of this characterization effort.

  3. Tensile deformation behavior of spray-deposited FVS0812 heat-resistant aluminum alloy sheet at elevated temperatures

    SciTech Connect

    Yan Qiqi; Fu Dingfa . E-mail: Fudingfa69@163.com; Deng Xuefeng; Zhang Hui; Chen Zhenhua

    2007-06-15

    The tensile deformation behavior of spray deposited FVS0812 heat-resistant aluminum alloy sheet was studied by uniaxial tension tests at temperatures ranging from 250 deg. C to 450 deg. C and strain rates from 0.001 to 0.1 s{sup -1}. The associated fracture surfaces were examined by scanning electron microscopy (SEM). The results show that the degree of work-hardening increases with decreasing temperature, and exhibits a small decrease with increasing strain rate; the strain rate sensitivity exponent increases with increasing temperature. The flow stress increases with increasing strain rate but decreases with increasing temperature. The total elongations to fracture increase not only with increasing temperature, but also with increasing strain rate, which is in marked contrast with the normal inverse dependence of elongation on the strain rate exhibited by conventional aluminum alloy sheets. The SEM fracture analysis indicates that the dependence of elongation on the strain rate may be due to the presence of a transition from plastic instability at lower strain rates to stable deformation at higher strain rates for fine-grained materials produced by spray deposition.

  4. The heat resistance of a polyurethane coating filled with modified nano-CaCO3

    NASA Astrophysics Data System (ADS)

    Li, Bin; Li, Song-Mei; Liu, Jian-Hua; Yu, Mei

    2014-10-01

    The modification of polyurethane coating by adding surface-modified CaCO3 nanoparticles (nano-CaCO3) was investigated in this paper. To improve interfacial interaction between the nano-CaCO3 and the polyurethane (PU) matrix, a silane coupling agent (KH560) was used to modify the nano-CaCO3. The grafting of KH560 on the nano-CaCO3 surfaces was characterized by the TEM, FTIR and TGA techniques. The modification of the nano-CaCO3 surfaces with KH560 was demonstrated to improve the dispersity of nano-CaCO3. FTIR, SEM and AFM were used to characterize the polyurethane coating. The FTIR spectrum indicated that the modification of nano-CaCO3 does not influence the chemical structure of the PU matrix. The roughness and gloss of the nanocomposite coatings containing various amount of nano-CaCO3 were evaluated using a roughness tester and a brightness meter. The heat resistance of the polyurethane coating containing various amounts of nano-CaCO3 was evaluated using the TGA technique. The results revealed that nano-CaCO3 treatment with KH560 improves the nanoparticle dispersion and heat-resistance of polyurethane coating.

  5. Phase composition of heat-resisting alloy modified by ageing and alloyed by rhenium

    NASA Astrophysics Data System (ADS)

    Koneva, Nina; Nikonenko, Elena; Popova, Natalya; Gibert, Ivan; Kozlov, Eduard

    2016-11-01

    The paper presents the transmission electron microscope (TEM) investigations of the structure of Ni-Al-Cr-based superalloy which is obtained by directional crystallization technique. The structural TEM investigations are carried out in two stages: 1) annealing at 1150°C for 1 h and 2) annealing at 1100°C for 480 h. The qualitative and quantitative analysis is given for the structure, phase composition and morphology of heat-resisting alloy additionally alloyed by rhenium Re both in the original state and after thermal treatment. The heat-resisting alloy comprises ˜70 at % Ni, ˜17 at % Al and ˜5 at % Cr. The total amount of the primary alloying elements of Mo, W, Ta, Ti, Co, La was ˜7 at % and 0.4 at % Re. It is shown that the structure of the superalloy is represented by (γ + γ')-phase mixture which has a morphologically correct crystallographic orientation and quasi-monocrystalline structure. σ-phase is formed in this superalloy due to rhenium. Since Re distribution in the alloy is not uniform, only a part of (γ + γ')-phase quasi-cuboids is distorted. It is shown that Re modification distorts the ideal structure of (γ + γ')-phase quasi-cuboids and results in the formation of β-, χ-and σ-phases.

  6. Modeling the influence of electron beam irradiation on the heat resistance of Bacillus cereus spores.

    PubMed

    Valero, M; Sarrías, J A; Alvarez, D; Salmerón, M C

    2006-06-01

    The effect of electron beam irradiation (EBI) on Bacillus cereus spore heat resistance was investigated. Irradiation with accelerated electrons had an important heat-sensitizing effect on distilled-water spore suspensions. After irradiation doses of 1.3, 3.1, or 5.7 kGy followed by heating at 90 degrees C, calculated D(90)-values for strains Escuela Politécnica Superior de Orihuela (EPSO)-41WR and EPSO-50UR were reduced more than 1.3, 2.4, and 4.6 times, respectively. Plots of calculated log D(T)-values versus irradiation doses (1.3, 3.1, and 5.7 kGy) yielded straight parallel lines for the 85-100 degrees C heating temperature range, which made it possible to develop an equation to predict the changes in heat sensitivity of B. cereus spores that occurred with changing irradiation dose. Radiation-induced heat-sensitivity was characterized by a z(EBI)-value which was determined as the irradiation dose that should be required to reduce the decimal reduction time (D(T)) by one log(10) cycle when log(10)D(T) was plotted against irradiation treatment. A model is proposed to describe the influence of a pre-irradiation treatment with electron beams followed by heating on the heat resistance of B. cereus spores. This study also suggests the potential use of EBI followed by heating for food preservation.

  7. Nanoemulsified D-Limonene Reduces the Heat Resistance of Salmonella Senftenberg over 50 Times

    PubMed Central

    Ros-Chumillas, María; Garre, Alberto; Maté, Javier; Palop, Alfredo; Periago, Paula M.

    2017-01-01

    Salmonella Senftenberg is a pathogen agent causative of foodborne disease and it is considered the most heat-resistant serovar within this genus. Food industries use heat treatment and chemical antimicrobials in order to eliminate this microorganism in food, but consumers prefer natural antimicrobials as essential oils and their components. This study evaluates the combined effect of thermal treatments and different concentrations of D-limonene nanoemulsion on the inactivation of Salmonella (S.) Senftenberg. The results showed an important effect of the nanoemulsified D-limonene on the heat resistance of S. Senftenberg. The δ50 °C value was reduced by 85%, 96% and 98% when 0.1, 0.5 and 1 mM of nanoemulsified D-limonene was added to the heating medium. The effect was kept along all the heating temperatures researched and the shape of the survival curves did not change with the addition of the antimicrobial. The results obtained in this research could be very useful for food industries for optimizing or improving heat treatments applied to food. PMID:28336899

  8. Heat-resistant organic molecular layer as a joint interface for metal reduction on plastics surfaces

    NASA Astrophysics Data System (ADS)

    Sang, Jing; Aisawa, Sumio; Hirahara, Hidetoshi; Kudo, Takahiro; Mori, Kunio

    2016-04-01

    Heat-resistant organic molecular layers have been fabricated by triazine-based silane coupling agent for metal reduction on plastic surfaces using adsorption method. These molecular layers were used as an interfacial layer between polyamide (PA6) and metal solution to reduce Ag+ ion to Ag0. The interfacial behaviors of triazine molecular layer at the interfaces between PA6 and Ag solution were investigated using quartz crystal microbalance (QCM). The kinetics of molecular adsorption on PA6 was investigated by using triazine-based silane coupling agent solutions at different pH and concentration. X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM), and local nano thermal analysis were employed to characterize the surfaces and interfaces. The nano thermal analysis results show that molecular layers of triazine-based silane coupling agent greatly improved heat resistance of PA6 resin from 170 °C up to 230 °C. This research developed an in-depth insight for molecular behaviors of triazine-based silane coupling agent at the PA6 and Ag solution interfaces and should be of significant value for interfacial research between plastics and metal solution in plating industry.

  9. Control of Byssochlamys and Related Heat-resistant Fungi in Grape Products

    PubMed Central

    King, A. Douglas; Michener, H. David; Ito, Keith A.

    1969-01-01

    Heat-resistant strains of Byssochlamys fulva, B. nivea, and other heat-resistant fungi were isolated from vineyard soil, grapes, grape-processing lines, and waste pomace. They are known to remain in grape juice occasionally and to grow in grape juice products. Ascospores of these fungi have a D value (decimal reduction time) of about 10 min at 190 F (88 C), but in the presence of 90 μliters of SO2 per liter (normally added to the juice) the D value was cut in half. Filtration through a commercial diatomaceous filter aid (also a common processing step) entrapped all but about 0.001% of experimentally added spores. Thus, heat in the presence of SO2 and filtration together can reduce the population of these spores by several orders of magnitude. Growth was also prevented by benzoate or sorbate in low concentrations. Oxygen must be reduced to extremely low levels before lack of oxygen limits growth. Images PMID:16349856

  10. Effect of pH on Thermoanaerobacterium thermosaccharolyticum DSM 571 growth, spore heat resistance and recovery.

    PubMed

    Mtimet, Narjes; Guégan, Stéphanie; Durand, Lucile; Mathot, Anne-Gabrielle; Venaille, Laurent; Leguérinel, Ivan; Coroller, Louis; Couvert, Olivier

    2016-05-01

    Thermophilic spore-forming bacteria are potential contaminants in several industrial sectors involving high temperatures (40-65 °C) in the manufacturing process. Among those thermophilic spore-forming bacteria, Thermoanaerobacterium thermosaccharolyticum, called "the swelling canned food spoiler", has generated interest over the last decade in the food sector. The aim of this study was to investigate and to model pH effect on growth, heat resistance and recovery abilities after a heat-treatment of T. thermosaccharolyticum DSM 571. Growth and sporulation were conducted on reinforced clostridium media and liver broth respectively. The highest spore heat resistances and the greatest recovery ability after a heat-treatment were obtained at pH condition allowing maximal growth rate. Growth and sporulation boundaries were estimated, then models using growth limits as main parameters were extended to describe and quantify the effect of pH on recovery of injured spores after a heat-treatment. So, cardinal values were used as a single set of parameters to describe growth, sporulation and recovery abilities. Besides, this work suggests that T. thermosaccharolyticum preserve its ability for germination and outgrowth after a heat-treatment at a low pH where other high resistant spore-forming bacteria like Geobacillus stearothermophilus are unable to grow.

  11. Transcriptome profiling of heat-resistant strain Bacillus licheniformis CGMCC3962 producing Maotai flavor.

    PubMed

    Wu, Qun; Xu, Yan

    2012-02-29

    Although Maotai flavor liquor is exclusive due to its soy sauce flavor, knowledge of its key compound and production mechanism is still scarce until now. To gain insight into the production mechanism of soy sauce flavor, a soy sauce flavor producing strain with high efficiency and heat-resistant capability was obtained, and the metabolic mechanism of the strain was investigated with the technique of microarray profiling. Because high temperature was a key factor for soy sauce flavor production, the global gene expression of this heat-resistant strain fermented at 55 °C was analyzed. Except for the responsive increase of heat shock proteins, which maintained cell survival during heat stress, biosynthesis of cysteine was also up-regulated. In addition, some metabolites were significantly increased when cysteine was added to the fermentation medium, such as 2,3-butanediol, 3-hydroxy-2-butanone, and tetramethylpyrazine, which were important flavor compounds in soy sauce flavor liquor and might be related with soy sauce flavor. The results indicated that cysteine might play an important role in the formation of soy sauce flavor compound, and it might act as an indirect precursor or stimulator of soy sauce flavor formation. This was the first use of the microarray profiling tool to investigate the fermentative strains for Chinese traditional liquor, which would allow a deeper insight into the mechanism of the formation of soy sauce flavor compound.

  12. Nanosized MX Precipitates in Ultra-Low-Carbon Ferritic/Martensitic Heat-Resistant Steels

    NASA Astrophysics Data System (ADS)

    Yin, Feng-Shi; Jung, Woo-Sang

    2009-02-01

    Nanosized MX precipitates in ultra-low-carbon ferritic/martensitic heat-resistant 9Cr-W-Mo-VNbTiN steels were characterized by transmission electron microscope (TEM) using carbon film replicas. The steels were prepared by vacuum induction melting followed by hot forging and rolling into plates. The plates were normalized at 1100 °C for 1 hour, cooled in air, and tempered at 700 °C for 1 hour. The results show that bimodal nanosized MX precipitates distribute densely and homogeneously in the matrix within martensitic lath after normalizing-and-tempering heat treatment. The larger nanosized MX precipitates with the size of 30 to 50 nm are rich in Nb, while the smaller ones with the size of about 10 nm contain less Nb but more V. Small addition of Ti causes an increase in the number of the larger nanosized MX precipitates. The total number density of the nanosized MX precipitates in the ultra-low-carbon ferritic/martensitic steels is measured to be over 300/ μm2, much higher than that in conventional ferritic/martensitic steels. Short-term creep test results show that the ultra-low-carbon ferritic/martensitic steels with high dense nanosized MX precipitates have much higher creep rupture strength than conventional ASME-P92 steel. The strength degradation of the ultra-low-carbon ferritic/martensitic heat-resistant steels during creep is also discussed in this article.

  13. Effect of heating rate on highly heat-resistant spore-forming microorganisms.

    PubMed

    Gómez-Jódar, Isabel; Ros-Chumillas, María; Palop, Alfredo

    2016-03-01

    Highly heat-resistant spore-forming Bacillus cause nonsterility problems in canned food and reduce the shelf life of many processed foods. The aim of this research was to evaluate the thermal inactivation of Bacillus sporothermodurans IIC65, Bacillus subtilis IC9, and Geobacillus stearothermophilus T26 under isothermal and nonisothermal conditions. The data obtained showed that B. sporothermodurans and B. subtilis were more heat resistant than G. stearothermophilus. The survival curves of B. sporothermodurans and B. subtilis showed shoulders, while the survival curves of G. stearothermophilus showed tails. Under nonisothermal treatment, at heating rates of 1 and 20 ℃/min, time needed to completely inactivate G. stearothermophilus was shorter than that required for B. sporothermodurans and B. subtilis. In complex heat treatments (heating-holding-cooling), the survival curves of B. sporothermodurans and B. subtilis showed the same activation shoulders than those obtained under isothermal treatments and the activation shoulders were again absent in the case of G. stearothermophilus. Predictions fitted quite well the data obtained for B. sporothermodurans. In contrast, the data for B. subtilis showed half a log cycle more survival than expected and in the case of G. stearothermophilus, the survival curve obtained showed much higher inactivation than expected.

  14. Developmental acclimation to low or high humidity conditions affect starvation and heat resistance of Drosophila melanogaster.

    PubMed

    Parkash, Ravi; Ranga, Poonam; Aggarwal, Dau Dayal

    2014-09-01

    Several Drosophila species originating from tropical humid localities are more resistant to starvation and heat stress than populations from high latitudes but mechanistic bases of such physiological changes are largely unknown. In order to test whether humidity levels affect starvation and heat resistance, we investigated developmental acclimation effects of low to high humidity conditions on the storage and utilization of energy resources, body mass, starvation survival, heat knockdown and heat survival of D. melanogaster. Isofemale lines reared under higher humidity (85% RH) stored significantly higher level of lipids and showed greater starvation survival hours but smaller in body size. In contrast, lines reared at low humidity evidenced reduced levels of body lipids and starvation resistance. Starvation resistance and lipid storage level were higher in females than males. However, the rate of utilization of lipids under starvation stress was lower for lines reared under higher humidity. Adult flies of lines reared at 65% RH and acclimated under high or low humidity condition for 200 hours also showed changes in resistance to starvation and heat but such effects were significantly lower as compared with developmental acclimation. Isofemale lines reared under higher humidity showed greater heat knockdown time and heat-shock survival. These laboratory observations on developmental and adult acclimation effects of low versus high humidity conditions have helped in explaining seasonal changes in resistance to starvation and heat of the wild-caught flies of D. melanogaster. Thus, we may suggest that wet versus drier conditions significantly affect starvation and heat resistance of D. melanogaster.

  15. Phototransduction genes are up-regulated in a global gene expression study of Drosophila melanogaster selected for heat resistance

    PubMed Central

    Nielsen, Morten Muhlig; Sørensen, Jesper Givskov; Kruhøffer, Mogens; Justesen, Just; Loeschcke, Volker

    2006-01-01

    The genetic architecture underlying heat resistance remains partly unclear despite the well-documented involvement of heat shock proteins (Hsps). It was previously shown that factors besides Hsps are likely to play an important role for heat resistance. In this study, gene expression arrays were used to make replicate measurements of gene expression before and up to 64 hours after a mild heat stress treatment, in flies selected for heat resistance and unselected control flies, to identify genes differentially expressed in heat resistance–selected flies. We found 108 genes up-regulated and 10 down-regulated using the Affymetrix gene expression platform. Among the up-regulated genes, a substantial number are involved in the phototransduction process. Another group of genes up-regulated in selected flies is characterized by also responding to heat shock treatment several hours after peak induction of known Hsps revert to nonstress levels. These findings suggest phototransduction genes to be critically involved in heat resistance, and support a role for components of the phototransduction process in stress-sensing mechanisms. In addition, the results suggest yet-uncharacterized genes responding to heat stress several hours after treatment to be involved in heat stress resistance. These findings mark an important increase in the understanding of heat resistance. PMID:17278881

  16. Career Options Research and Development. Materials From Phase II Final Report.

    ERIC Educational Resources Information Center

    YMCA of Metropolitan Chicago, IL. Career Options Research and Development (CORD).

    The Social Service Aide Project for the training and education of paraprofessionals is a part of the Career Options Research and Development project of the Young Men's Christian Association of Chicago. These materials from the Phase II Final Report include: (1) Fourth Quarterly Progress Report (July-September 1970)," (2) "Systems…

  17. Strand II: Sociological Health Problems. Prototype Curriculum Materials for the Elementary and Secondary Grades.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

    These publications contain three of the topics for Strand II, Sociological Health Problems, which have been prepared as part of the kindergarten through twelve health syllabus revision project. The material included is intended for use in grades four through twelve. The topics covered are alcohol education, drugs and narcotics, and smoking. The…

  18. Material Characterization methods in InAs/InAsSb Type-II superlattices

    SciTech Connect

    Kadlec, Emil Andrew

    2016-12-01

    This document presents a thesis proposal with three topics. It describes an in-depth comparison of lifetime measurement methods for material characterization of InAs/InAsSb type-II superlattices; develops a characterization method based on the 2nd harmonic of a modulated carrier density; and relates lifetime measurements to device performance.

  19. Teaching General and Systemic Pathology in a New Veterinary School. II. Materials and Costs

    ERIC Educational Resources Information Center

    Crowell, W. A.; And Others

    1976-01-01

    The amounts, types and costs of materials used to initiate a Year II (sophomore) pathology course in the L.S.U. School of Veterinary Medicine were tabulated. Use of the autotutorial method resulted in slightly greater costs than the traditional method, but this was offset by general satisfaction with it. (Author/LBH)

  20. Selection and Evaluation of Heat-Resistant Alloys for Planar SOFC Interconnect Applications

    SciTech Connect

    Yang, Z Gary; Weil, K. Scott; Paxton, Dean M.; Stevenson, Jeffry W.

    2002-11-21

    Over the past several years, the steady reduction in SOFC operating temperatures to the intermediate range of 700~850oC [1] has made it feasible for lanthanum chromite to be supplanted by metals or alloys as the interconnect materials. Compared to doped lanthanum chromite, metals or alloys offer significantly lower raw material and fabrication costs. However, to be a durable and reliable, a metal or alloy has to satisfy several functional requirements specific to the interconnect under SOFC operating conditions. Specifically, the interconnect metal or alloy should possess the following properties: (i) Good surface stability (resistance to oxidation, hot corrosion, and carburization) in both cathodic (air) and anodic (fuel) atmospheres; (ii) Thermal expansion matching to the ceramic PEN (positive cathode-electrolyte-negative anode) and seal materials (as least for a rigid seal design); (iii) High electrical conductivity through both the bulk material and in-situ formed oxide scales; (iv) Bulk and interfacial thermal mechanical reliability and durability at the operating temperature; (v) Compatibility with other materials in contact with interconnects such as seals and electrical contact materials.

  1. Guidelines for experimental design protocol and validation procedure for the measurement of heat resistance of microorganisms in milk.

    PubMed

    Condron, Robin; Farrokh, Choreh; Jordan, Kieran; McClure, Peter; Ross, Tom; Cerf, Olivier

    2015-01-02

    Studies on the heat resistance of dairy pathogens are a vital part of assessing the safety of dairy products. However, harmonized methodology for the study of heat resistance of food pathogens is lacking, even though there is a need for such harmonized experimental design protocols and for harmonized validation procedures for heat treatment studies. Such an approach is of particular importance to allow international agreement on appropriate risk management of emerging potential hazards for human and animal health. This paper is working toward establishment of a harmonized protocol for the study of the heat resistance of pathogens, identifying critical issues for establishment of internationally agreed protocols, including a harmonized framework for reporting and interpretation of heat inactivation studies of potentially pathogenic microorganisms.

  2. Heat-resistant variants of the Chinese hamster ovary cell: alteration of cellular structure and expression of vimentin.

    PubMed

    Lee, Y J; Hou, Z Z; Curetty, L; Armour, E P; al-Saadi, A; Bernstein, J; Corry, P M

    1992-04-01

    Three heat-resistant mutant cell lines (78-1, 78-2, 78-3) were previously selected from Chinese hamster ovary cells. In this study, we investigated whether the differences in intrinsic thermal sensitivity result from alteration of stress protein levels or cellular structural changes. Although there was no significant difference in the levels of stress proteins, i.e., constitutive HSP70 in wild type and three heat-resistant mutant strains, there were marked differences in the amounts of vimentin among the cell lines. Two-dimensional gel electrophoresis and Western blot showed a 2.3-2.9-fold increase in the level of vimentin in the mutant cells under normal growth conditions. Northern blot also revealed higher amounts of vimentin mRNA in the mutant cells. Electron microscopy and immunofluorescence suggest that increased amounts of the vimentin-containing intermediate filaments are correlated with the heat-resistant phenotypes.

  3. EFFECT OF SPORULATION MEDIUM ON HEAT RESISTANCE, CHEMICAL COMPOSITION, AND GERMINATION OF BACILLUS MEGATERIUM SPORES1

    PubMed Central

    Levinson, Hillel S.; Hyatt, Mildred T.

    1964-01-01

    Levinson, Hillel S. (U.S. Army Natick Laboratories, Natick, Mass.), and Mildred T. Hyatt. Effect of sporulation medium on heat resistance, chemical composition, and germination of Bacillus megaterium spores. J. Bacteriol. 87:876–886. 1964.—Bacillus megaterium spores, grown on variously supplemented media, had varying concentrations of P, Ca, Mn, or dipicolinic acid. Supplementation with CaCl2 yielded spores with increased heat resistance; addition of l-glutamate, l-proline, or increase of the phosphate concentration yielded spores with reduced heat resistance. Germination characteristics depended on both the sporulation medium and the germinant (glucose, l-alanine, l-leucine, or KNO3); pronounced differences were demonstrable with glucose and l-alanine, which trigger germination via different metabolic pathways. An increase in CaCl2 during sporulation yielded spores with increased germination in glucose but not in l-alanine. Germination in l-alanine was optimal with spores produced on media containing 0.1 mm MnCl2, but germination of such spores was minimal in glucose. An increase in the sporulation medium phosphate decreased the initial germination rate in glucose, but not in l-alanine. Spores produced in CaCl2-supplemented media had increased heat-activation requirements (increased dormancy) for germination induced by l-alanine, and decreased heat-shock requirements for glucose-induced germination. An increase of sporulation phosphate yielded spores with reduced dormancy for germination induced by l-alanine, but with unchanged dormancy on the other germinants. Spores produced with added l-glutamate had reduced dormancy for glucose-induced germination, and increased dormancy for germination induced by l-alanine. Addition of CaCl2 or l-glutamate to the sporulation medium yielded spores with increased sensitivity to “ionic germination” (with KI). Spores from synthetic medium were incapacitated for full postgerminative development, as shown by repression of

  4. Heat resistance of histamine-producing bacteria in irradiated tuna loins.

    PubMed

    Enache, Elena; Kataoka, Ai; Black, D Glenn; Weddig, Lisa; Hayman, Melinda; Bjornsdottir-Butler, Kristin

    2013-09-01

    Consumption of foods high in biogenic amines leads to an illness known as histamine, or scombrotoxin, poisoning. The illness is commonly associated with consumption of fish with high levels of histamine ( $ 500 ppm). The objective of this study was to determine and compare the heat resistance of five histamine-producing bacteria in irradiated albacore tuna loins. Heat-resistance parameters (D- and z-values) were determined for Morganella morganii, Raoultella planticola, Hafnia alvei, and Enterobacter aerogenes. D- or z-values were not determined for Photobacterium damselae, which was the most heat-sensitive organism in this study. P. damselae declined > 5.9 log CFU/g after a heat treatment of 50°C for 10 min, 54°C for 3 min, and 56°C for 0.5 min. M. morganii was the most heat-resistant histamine-producing bacteria in albacore tuna loins, followed by E. aerogenes, H. alvei, and R. planticola. M. morganii and E. aerogenes had the highest D(50°C), 49.7 ± 17.57 and 51.8 ± 17.38 min, respectively. In addition, M. morganii had the highest D-values for all other temperatures (54, 56, and 58°C) tested. D- and zvalues were also determined for M. morganii in skipjack tuna. While no significant (P > 0.05) difference was observed between D(54°C) and D(56°C) of M. morganii in either albacore or skipjack tuna, the D(58°C) (0.4 ± 0.17 min) was significantly lower (P < 0.05) in skipjack than in albacore (0.9 ± 0.24 min). The z-values for all organisms tested were in the range of 3.2 to 3.8°C. This study suggests that heat treatment designed to control M. morganii in tuna loins is sufficient for controlling histamine-producing bacteria in canned-tuna processing environments.

  5. Liquid Inclusions in Heat-Resistant Steel Containing Rare Earth Elements

    NASA Astrophysics Data System (ADS)

    Li, Yandong; Liu, Chengjun; Zhang, Tongsheng; Jiang, Maofa; Peng, Cheng

    2017-04-01

    Abundant thermodynamic data of pure substances were incorporated in the coupled thermodynamic model of inclusion precipitation and solute micro-segregation during the solidification of heat-resistant steel containing rare earth elements. The liquid inclusions Ce2 x Al2 y Si1- x-y O z (0 < x < 1, 0 < y < x and z = 1 - x - y) were first introduced to ensure the model more accurately. And the computational method for generation Gibbs free energy of liquid inclusions in molten steel was given. The accuracy of accomplished model was validated through plant trials, lab-scale experiments, and the data published in the literature. The comparisons of results calculated by FactSage with the model were also discussed. Finally, the stable area of liquid inclusions was predicted and the liquid inclusions with larger size were found in the preliminary experiments.

  6. Fire- and heat-resistant laminating resins based on maleimido-substituted aromatic cyclotriphosphazenes

    NASA Technical Reports Server (NTRS)

    Kumar, D.; Fohlen, G. M.; Parker, J. A.

    1983-01-01

    A novel class of flame- and heat-resistant polymers has been synthesized by the thermal polymerization of maleimido-substituted aromatic cyclotriphosphazenes. The polymer obtained from tris-(aminophenoxy)tris(maleimidophenoxy)cyclotriphosphazene has good thermal stability and is noteworthy for its high char yield, viz., 82 percent at 800 C in nitrogen and 81 percent at 700 C in air. Graphite-fabric laminates prepared with this polymer did not burn in pure oxygen, even at 300 C, and were tested for mechanical properties. Hexakis(4-maleimidophenoxy)cyclotriphosphazene and some fluorine-containing monomers have also been synthesized. The structures of these cyclic phosphazene precursors and polymers were characterized by FT IR spectrophotometry, H-1 NMR, F-19 NMR, and P-31 solid-state magic angle spinning NMR spectroscopy, and mass spectrometry. The curing behavior of the polymer precursors and the thermal stabilities of the polymers were evaluated by differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA).

  7. Heat-resistant fiber and/or fire retardant synthetic fiber

    SciTech Connect

    Sakurada, I.; Kaji, K.; Okada, T.

    1984-08-21

    A heat resistant and/or fire retardant synthetic fiber is obtained by a process comprising immersing a polyethylene fiber into a solution of acrylic acid or impregnating a polyethylene fiber with a solution of acrylic acid and irradiating the polyethylene fiber with an ionizing radiation to graft polymerize the polyethylene fiber with at least 15%, based on the weight of the polyethylene fiber, of acrylic acid, or a process comprising irradiating a polyethylene fiber with an ionizing radiation and then immersing the polyethylene fiber into a solution of acrylic acid or impregnating the polyethylene fiber with a solution of acrylic acid to graft polymerize the polyethylene fiber with at least 15%, based on the weight of the polyethylene fiber, of acrylic acid.

  8. The Z-Phase in 9Cr Ferritic/martensitic Heat Resistant Steel

    NASA Astrophysics Data System (ADS)

    Yin, Fengshi; Chen, Fuxia; Jiang, Xuebo; Xue, Bing; Zhou, Li; Jung, Woosang

    The precipitation behavior of Z-phase was investigated during long-term aging at 650°C in an ultra low carbon 9Cr ferritic/martensitic heat resistant steel. The steel was prepared by vacuum induction melting followed by hot forging and rolling into a plate. The plate was normalized at 1100°C for 1h, cooled in air and tempered at 700°C for 1h. Bimodal nano-sized MX precipitates distribute densely and homogeneously in the matrix within martensitic lath after normalizing-and-tempering heat treatment. After aging at 650°C for 1200h, the Z-phase was found to nucleate on the larger nano-sized MX. The Z-phase and MX have the following orientation relationship: <112>Z-phase//<001>MX and (1bar 10){Z-phase}//(200){MX} .

  9. Heat-resistant coatings for niobium and niobium-base alloys (review)

    SciTech Connect

    Dzyadykevich, Y.V.

    1986-06-01

    The author shows that it is possible to formulate the directions in developments whose purpose is to increase the heat resistance of niobium and niobium-base alloys. These include the creation of a barrier layer for retarding undesirable diffusion processes at the coating-base interface, the formation on niobium alloy parts of alloy silicide layers, the obtaining on parts operating at temperatures above 1300 C of a coating of molybdenum disilicide, the application to previously siliconized niobium alloys of a barrier layer of heterophase coatings, the matrix of which is a low-melting component and the filler refractory compounds, and the addition to the oxidizing gaseous medium of various additions increasing the service life of the protective coating.

  10. Scorpion Venom Heat-Resistant Peptide Protects Transgenic Caenorhabditis elegans from β-Amyloid Toxicity

    PubMed Central

    Zhang, Xiao-Gang; Wang, Xi; Zhou, Ting-Ting; Wu, Xue-Fei; Peng, Yan; Zhang, Wan-Qin; Li, Shao; Zhao, Jie

    2016-01-01

    Scorpion venom heat-resistant peptide (SVHRP) is a component purified from Buthus martensii Karsch scorpion venom. Our previous studies found SVHRP could enhance neurogenesis and inhibit microglia-mediated neuroinflammation in vivo. Here, we use the transgenic CL4176, CL2006, and CL2355 strains of Caenorhabditis elegans which express the human Aβ1-42 to investigate the effects and the possible mechanisms of SVHRP mediated protection against Aβ toxicity in vivo. The results showed that SVHRP-fed worms displayed remarkably decreased paralysis, less abundant toxic Aβ oligomers, reduced Aβ plaque deposition with respect to untreated animals. SVHRP also suppressed neuronal Aβ expression-induced defects in chemotaxis behavior and attenuated levels of ROS in the transgenic C. elegans. Taken together, these results suggest SVHRP could protect against Aβ-induced toxicity in C. elegans. Further studies need to be conducted in murine models and humans to analyze the effectiveness of the peptide. PMID:27507947

  11. Dry-heat resistance of selected psychrophiles. [Viking lander in spacecraft sterilization

    NASA Technical Reports Server (NTRS)

    Winans, L.; Pflug, I. J.; Foster, T. L.

    1977-01-01

    The dry-heat resistance characteristics of spores of psychrophilic organisms isolated from soil samples from the Viking spacecraft assembly areas at Cape Kennedy Space Flight Center, Cape Canaveral, Fla., were studied. Spore suspensions were produced, and dry-heat D values were determined for the microorganisms that demonstrated growth or survival under a simulated Martian environment. The dry-heat tests were carried out by using the planchet-boat-hot plate system at 110 and 125 C with an ambient relative humidity of 50% at 22 C. The spores evaluated had a relatively low resistance to dry heat. D (110 C) values ranged from 7.5 to 122 min, whereas the D (125 C) values ranged from less than 1.0 to 9.8 min.

  12. Water soluble and heat resistant polymers by free radical polymerization of lactic acid-based monomers

    NASA Astrophysics Data System (ADS)

    Tanaka, Hitoshi; Kibayashi, Tatsuya; Niwa, Miki

    2013-08-01

    Tactic heat resistant polymer was prepared by free radical polymerization of lactic acid-based monomers, i.e. chiral 2-isopropyl-5-methylene-1,3-dioxolan-4-ones (1). The polymerization of 1 proceeded smoothly without ring-opening to give a polymer with high isotacticity (mm) of 29.7~100% and glass transition temperature (Tg) of 172~213°C. 1 also showed high reactivity in the copolymerization with styrene and methyl methacrylate, and the incorporation of 1 unit in the copolymer structure increased Tg of each polymer. In addition, hydrolysis of poly(1) produced a new type of water soluble poly(lactic acid), i.e. poly(α-hydroxy acrylate), and poly(α-hydroxy acrylate-co-divinyl benzene) hydrogel absorbed water as high as 1000 times of the original polymer weight.

  13. Acute effects of heated resistance exercise in female and male power athletes.

    PubMed

    Casadio, Julia R; Storey, Adam G; Merien, Fabrice; Kilding, Andrew E; Cotter, James D; Laursen, Paul B

    2017-07-26

    To determine the effects of heated resistance exercise on thermal strain, neuromuscular function and hormonal responses in power athletes. Sixteen (n = 8 female; 8 male) highly trained power athletes completed a combined strength and power resistance exercise session in hot (HOT ~30 °C) and temperate (CON ~20 °C) conditions. Human growth hormone (hGH), cortisol and testosterone concentrations in plasma, peak power (counter-movement jump, CMJ) and peak force (isometric mid-thigh pull) were measured before and after each training session; thermoregulatory responses were monitored during training. Skin temperature, thermal sensation and thermal discomfort were higher in HOT compared with CON. Sweat rate was higher in HOT for males only. Compared with CON, HOT had trivial effects on core temperature and heart rate. During HOT, there was a possible increase in upper-body power (medicine ball throw) in females [3.4% (90% CL -1.5, 8.6)] and males [(3.3% (-0.1, 6.9)], while lower-body power (vertical jump) was enhanced in males only [3.2% (-0.4, 6.9)]. Following HOT, CMJ peak power [4.4% (2.5; 6.3)] and strength [8.2% (3.1, 13.6)] were enhanced in female athletes, compared with CON, while effects in males were unclear. Plasma hGH concentration increased in females [83% (18; 183)] and males [107% (-21; 444)] in HOT compared with CON, whereas differential changes occurred for cortisol and testosterone. Heated resistance exercise enhanced power and increased plasma hGH concentration in female and males power athletes. Further research is required to assess the ergogenic potential of resistance exercise in the heat.

  14. Microstructure Changing of P91 Heat Resistant Steel during Short-Term Creep at 873K

    NASA Astrophysics Data System (ADS)

    Jiaqiang, Gao; Qijiang, Wang; Yedong, Zhou

    The working temperature of main steam pipe in (ultra-)supercritical power generating units is 873K, and creep behavior of P91 was tested under this temperature with the stress of 140MPa for 5534h, and the minimum creep rate was 0.2μm/h. Then creep test for short period were conducted for 100h and 1800h, and samples considered as primary creep stage and steady-state creep stage respectively. These samples as well as initial state and creep ruptured samples were observed by transmission electronic microscope(TEM) mainly under scanning mode(STEM). The precipitates in P91 heat resistant steel at different states were studied in detail with two methods: carbon extraction replica and twin-jet thin foil. It was shown that microstructure of P91 heat resistant steel after creep was degraded, especially for accelerated stage. That means the density of dislocation decrease, and the width of martensitic lath as well as the size of sub-grain were coarsen. It can be seen that the mean size of precipitates was coarsen slightly too. There were Laves phases in sample of steady-state creep stage with the size of 150nm. While it was coarse easily to large size more than 500nm in creep-ruptured samples. It would exert strengthening effect by precipitating along lath boundaries and sub-grain boundaries in early stage of creep. But Laves phases were prone to coarsen, which would weaken their strengthening effect and become detrimental to long term creep.

  15. Surface texturing effect on crack suppression of SiO2 film formed by F2 laser-induced photochemical surface modification of silicone on polycarbonate under heat resistance test

    NASA Astrophysics Data System (ADS)

    Nojiri, Hidetoshi; Okoshi, Masayuki

    2017-08-01

    A crack-free SiO2 film was successfully fabricated on silicone-coated polycarbonate (PC) even under heat resistance tests at 100 and 120 °C for 3 h by an additional rubbing treatment with steel wool for use as an automobile window material. The SiO2 film was formed by 157 nm F2 laser-induced photochemical surface modification of silicone on PC. The modified SiO2 layer was also zoned with a mesh mask during the laser irradiation. The zoned SiO2 layer was effective for suppressing cracks during laser irradiation. However, even the zoned layer caused cracks under heat resistance tests. A mechanism of the cracking was analyzed on the basis of observations of sample surfaces by confocal laser microscopy. The rubbed samples showed high heat resistance. By atomic force microscopy, the surface of the modified SiO2 layer was clearly observed to be textured, which reduced the large difference in the thermal expansion coefficient between SiO2 and silicone on PC, thus maintaining optical transparency.

  16. Porous membrane with high curvature, three-dimensional heat-resistance skeleton: a new and practical separator candidate for high safety lithium ion battery

    PubMed Central

    Shi, Junli; Xia, Yonggao; Yuan, Zhizhang; Hu, Huasheng; Li, Xianfeng; Zhang, Huamin; Liu, Zhaoping

    2015-01-01

    Separators with high reliability and security are in urgent demand for the advancement of high performance lithium ion batteries. Here, we present a new and practical porous membrane with three-dimension (3D) heat-resistant skeleton and high curvature pore structure as a promising separator candidate to facilitate advances in battery safety and performances beyond those obtained from the conventional separators. The unique material properties combining with the well-developed structural characteristics enable the 3D porous skeleton to own several favorable properties, including superior thermal stability, good wettability with liquid electrolyte, high ion conductivity and internal short-circuit protection function, etc. which give rise to acceptable battery performances. Considering the simply and cost-effective preparation process, the porous membrane is deemed to be an interesting direction for the future lithium ion battery separator. PMID:25653104

  17. Porous membrane with high curvature, three-dimensional heat-resistance skeleton: a new and practical separator candidate for high safety lithium ion battery.

    PubMed

    Shi, Junli; Xia, Yonggao; Yuan, Zhizhang; Hu, Huasheng; Li, Xianfeng; Zhang, Huamin; Liu, Zhaoping

    2015-02-05

    Separators with high reliability and security are in urgent demand for the advancement of high performance lithium ion batteries. Here, we present a new and practical porous membrane with three-dimension (3D) heat-resistant skeleton and high curvature pore structure as a promising separator candidate to facilitate advances in battery safety and performances beyond those obtained from the conventional separators. The unique material properties combining with the well-developed structural characteristics enable the 3D porous skeleton to own several favorable properties, including superior thermal stability, good wettability with liquid electrolyte, high ion conductivity and internal short-circuit protection function, etc. which give rise to acceptable battery performances. Considering the simply and cost-effective preparation process, the porous membrane is deemed to be an interesting direction for the future lithium ion battery separator.

  18. Development of Simultaneous Corrosion Barrier and Optimized Microstructure in FeCrAl Heat-Resistant Alloy for Energy Applications. Part 1: The Protective Scale

    NASA Astrophysics Data System (ADS)

    Pimentel, G.; Aranda, M. M.; Chao, J.; González-Carrasco, J. L.; Capdevila, C.

    2015-09-01

    Coarse-grained Fe-based oxide dispersion-strengthened (ODS) steels are a class of advanced materials for combined cycle gas turbine systems to deal with operating temperatures and pressures of around 1100°C and 15-30 bar in aggressive environments, which would increase biomass energy conversion efficiencies up to 45% and above. This two-part paper reports the possibility of the development of simultaneous corrosion barrier and optimized microstructure in a FeCrAl heat-resistant alloy for energy applications. The first part reports the mechanism of generating a dense, self-healing α-alumina layer by thermal oxidation, during a heat treatment that leads to a coarse-grained microstructure with a potential value for high-temperature creep resistance in a FeCrAl ODS ferritic alloy, which will be described in more detail in the second part.

  19. Synthesis of amino functionalized magnetic graphenes composite material and its application to remove Cr(VI), Pb(II), Hg(II), Cd(II) and Ni(II) from contaminated water.

    PubMed

    Guo, Xiaoyao; Du, Bin; Wei, Qin; Yang, Jian; Hu, Lihua; Yan, Liangguo; Xu, Weiying

    2014-08-15

    In the present study, a kind of graphenes magnetic material (Fe3O4-GS) was prepared by compositing graphene sheet with ferroferric oxide, and shown to be effective for removing Cr(VI), Pb(II), Hg(II), Cd(II) and Ni(II) ions from aqueous solution. The synthesized sorbent was characterized by SEM, TEM, FTIR, XRD, XPS and BET, respectively. The pHZPC value of the sorbent was estimated to be 3.5 by alkaline-titration methods. Fe3O4-GS can be simply recovered from water with magnetic separation at low magnetic field within one minute. The sorption capacities of the metals were 17.29, 27.95, 23.03, 27.83 and 22.07 mg g(-1) for Cr(VI), Pb(II), Hg(II), Cd(II) and Ni(II), respectively. Kinetic data showed good correlation with pseudo-second-order equation and the Freundlich model was found to fit for the isotherm data of all the heavy metal ions. It was found that the metals sorption was accomplished mainly via chelation or ion exchange. The results of thermodynamic studies illustrate that the adsorption process was endothermic and spontaneous in nature.

  20. Luminescent liquid crystalline materials based on palladium(II) imine derivatives containing the 2-phenylpyridine core.

    PubMed

    Micutz, Marin; Iliş, Monica; Staicu, Teodora; Dumitraşcu, Florea; Pasuk, Iuliana; Molard, Yann; Roisnel, Thierry; Cîrcu, Viorel

    2014-01-21

    In this work we report our studies concerning the synthesis and characterisation of a series of imine derivatives that incorporate the 2-phenylpyridine (2-ppy) core. These derivatives were used in the cyclometalating reactions of platinum(II) or palladium(II) in order to prepare several complexes with liquid crystalline properties. Depending on the starting materials used as well as the solvents employed, different metal complexes were obtained, some of them showing both liquid crystalline behaviour and luminescence properties at room temperature. It was found that, even if there are two competing coordination sites, the cyclometalation process takes place always at the 2-ppy core with (for Pt) or without (for Pd) the imine bond cleavage. We successfully showed that it is possible to prepare emissive room temperature liquid crystalline materials based on double cyclopalladated heteroleptic complexes by varying the volume fraction of the long flexible alkyl tails on the ancillary benzoylthiourea (BTU) ligands.

  1. New hybrid materials as Zn(II) sorbents in water samples

    SciTech Connect

    Perez-Quintanilla, Damian

    2010-09-15

    Mesoporous silicas have been chemically modified with 5-mercapto-1-methyltetrazole (MTTZ) obtaining hybrid materials denominated MTTZ-MSU-2 and MTTZ-HMS. These materials were employed as Zn(II) sorbents from aqueous media at room temperature. The effect of several variables (stirring time, pH, presence of other metals) has been studied using batch and column techniques. Flame atomic absorption spectrometry (FAAS) was used to determinate Zn(II) concentration in the filtrate or in the eluted solution after the adsorption process. The results indicate that under pH 8, the maximum adsorption value was 0.94 {+-} 0.01 and 0.72 {+-} 0.01 mmol Zn(II)/g for MTTZ-MSU-2 and MTTZ-HMS, respectively. In tap water samples, a preconcentration factor of 200 was obtained. On the basis of these results, it can be concluded that it is possible to modify chemically MSU-2 and HMS with 5-mercapto-1-methyltetrazole and to use the resulting modified mesoporous silica as an effective adsorbent for Zn(II) in aqueous media.

  2. High power CO II lasers and their material processing applications at Centre for Advanced Technology, India

    NASA Astrophysics Data System (ADS)

    Nath, A. K.; Paul, C. P.; Rao, B. T.; Kau, R.; Raghu, T.; Mazumdar, J. Dutta; Dayal, R. K.; Mudali, U. Kamachi; Sastikumar, D.; Gandhi, B. K.

    2006-01-01

    We have developed high power transverse flow (TF) CW CO II lasers up to 15kW, a high repetition rate TEA CO II laser of 500Hz, 500W average power and a RF excited fast axial flow CO II laser at the Centre for Advanced Technology and have carried out various material processing applications with these lasers. We observed very little variation of discharge voltage with electrode gap in TF CO II lasers. With optimally modulated laser beam we obtained better results in laser piercing and cutting of titanium and resolidification of 3 16L stainless steel weld-metal for improving intergranular corrosion resistance. We carried out microstructure and phase analysis of laser bent 304 stainless steel sheet and optimum process zones were obtained. We carried out laser cladding of 316L stainless steel and Al-alloy substrates with Mo, WC, and Cr IIC 3 powder to improve their wear characteristics. We developed a laser rapid manufacturing facility and fabricated components of various geometries with minimum surface roughness of 5-7 microns Ra and surface waviness of 45 microns between overlapped layers using Colmonoy-6, 3 16L stainless steel and Inconel powders. Cutting of thick concrete blocks by repeated laser glazing followed by mechanical scrubbing process and drilling holes on a vertical concrete with laser beam incident at an optimum angle allowing molten material to flow out under gravity were also done. Some of these studies are briefly presented here.

  3. Effects of pulp capping materials on fracture resistance of Class II composite restorations

    PubMed Central

    Kucukyilmaz, Ebru; Yasa, Bilal; Akcay, Merve; Savas, Selcuk; Kavrik, Fevzi

    2015-01-01

    Objective: The aim of this study was to investigate the effect of cavity design and the type of pulp capping materials on the fracture resistance of Class II composite restorations. Materials and Methods: Sixty freshly extracted, sound molar teeth were selected for the study. A dovetail cavity on the mesio-occlusal and a slot cavity on disto-occlusal surfaces of each tooth were prepared, and the teeth were divided 4 groups which one of them as a control group. The pulp capping materials (TheraCal LC, Calcimol LC, Dycal) applied on pulpo-axial wall of each cavity, and the restoration was completed with composite resin. The teeth were subjected to a compressive load in a universal mechanical testing machine. The surfaces of the tooth and restoration were examined under a stereomicroscope. The data were analyzed using factorial analysis of variance and Tukey's test. Results: For pulp capping materials, the highest fracture load (931.15 ± 203.81 N) and the lowest fracture load (832.28 ± 245.75 N) were calculated for Control and Dycal group, respectively. However, there were no statistically significant differences among all groups (P > 0.05). The fracture load of the dovetail groups was significantly higher than those of the slot cavity groups (P < 0.05). Conclusion: Dovetail cavity design shows better fracture resistance in Class II composite restorations, independent of used or not used pulp capping materials. PMID:26038653

  4. Clinical Evaluation of Restorative Materials in Primary Teeth Class II Lesions.

    PubMed

    Sengul, F; Gurbuz, T

    2015-01-01

    The aim of this study was to evaluate clinical success of primary teeth class II lesions restored with different restorative materials [Hybrid Composite Resin (HCR), Resin Modified Glass Ionomer Cement (RMGIC), compomer, and Giomer Composite Resin (GCR)] followed up for 24 months. This study was carried out on 146 primary molars of 41 children in the age range of 5-7 years. The class II lesions in primary molars of a patient were restored using different restorative materials. Restorations were evaluated according to FDI-criteria and their survival rates were determined. Data were analysed with Pearson chi-square, Kaplan-Meier and Wilcoxon (Breslow) tests (α = 0.05). The failure rates of restorative materials were as follows: compomer 33.3%, RMGIC 28.1%, HCR 22.5% and GCR 21.1%. While the functional failure was the most important factor in restorative material failure, RMGIC was the most successful material in terms of biological evaluation criterion and GCR had the longest survival rate.

  5. An Overview of Materials Structures for Extreme Environments Efforts for 2015 SBIR Phases I and II

    NASA Technical Reports Server (NTRS)

    Nguyen, Hung D.; Steele, Gynelle C.

    2017-01-01

    Technological innovation is the overall focus of NASA's Small Business Innovation Research (SBIR) program. The program invests in the development of innovative concepts and technologies to help NASA's mission directorates address critical research and development needs for Agency projects. This report highlights innovative SBIR 2015 Phase I and II projects that specifically address areas in Materials and Structures for Extreme Environments, one of six core competencies at NASA Glenn Research Center. Each article describes an innovation, defines its technical objective, and highlights NASA applications as well as commercial and industrial applications. Ten technologies are featured: metamaterials-inspired aerospace structures, metallic joining to advanced ceramic composites, multifunctional polyolefin matrix composite structures, integrated reacting fluid dynamics and predictive materials degradation models for propulsion system conditions, lightweight inflatable structural airlock (LISA), copolymer materials for fused deposition modeling 3-D printing of nonstandard plastics, Type II strained layer superlattice materials development for space-based focal plane array applications, hydrogenous polymer-regolith composites for radiation-shielding materials, a ceramic matrix composite environmental barrier coating durability model, and advanced composite truss printing for large solar array structures. This report serves as an opportunity for NASA engineers, researchers, program managers, and other personnel to learn about innovations in this technology area as well as possibilities for collaboration with innovative small businesses that could benefit NASA programs and projects.

  6. Effect of cyclic loading on the bond strength of class II restorations with different composite materials.

    PubMed

    Cavalcanti, Andrea Nóbrega; Mitsui, Fabio Hiroyuki Ogata; Silva, Flávia; Peris, Alessandra Rezende; Bedran-Russo, Ana; Marchi, Giselle Maria

    2008-01-01

    This study evaluated the effect of cyclic loading on the bond strength of Class II restorations using different composite materials. Class II preparations with gingival margins located in dentin were performed on the mesial surface of 80 bovine incisors. The teeth were randomly allocated to eight groups (n=10) according to resin composite (Filtek Z250, Filtek Supreme, Tetric Ceram HB and Esthet-X) and use of cyclic loading. The restorations were bonded with the Single Bond adhesive system. Simulated aging groups were cyclic loaded for 200,000 cycles with 80N load (2Hz). The specimens were vertically sectioned (two slabs per restoration) and further trimmed into an hour-glass shape at the adhesive interface to obtain a final bonded area 1 mm2. Samples were placed in an apparatus and tested under tension using a universal testing machine. The data were analyzed using two-way ANOVA and Tukey test with a 95% confidence level. Aged groups presented significantly lower means when compared to the groups that were not aged (p=0.03). However, significant differences among composite materials were not observed (p=0.17). Regardless of the restorative composite material used, it could be concluded that the bond strength of Class II restorations at the gingival wall was affected by simulated cyclic loading.

  7. Turn Up the Heat—Food and Clinical Escherichia coli Isolates Feature Two Transferrable Loci of Heat Resistance

    PubMed Central

    Boll, Erik J.; Marti, Roger; Hasman, Henrik; Overballe-Petersen, Søren; Stegger, Marc; Ng, Kim; Knøchel, Susanne; Krogfelt, Karen A.; Hummerjohann, Joerg; Struve, Carsten

    2017-01-01

    Heat treatment is a widely used process to reduce bacterial loads in the food industry or to decontaminate surfaces, e.g., in hospital settings. However, there are situations where lower temperatures must be employed, for instance in case of food production such as raw milk cheese or for decontamination of medical devices such as thermo-labile flexible endoscopes. A recently identified locus of heat resistance (LHR) has been shown to be present in and confer heat resistance to a variety of Enterobacteriaceae, including Escherichia coli isolates from food production settings and clinical ESBL-producing E. coli isolates. Here, we describe the presence of two distinct LHR variants within a particularly heat resistant E. coli raw milk cheese isolate. We demonstrate for the first time in this species the presence of one of these LHRs on a plasmid, designated pFAM21805, also encoding type 3 fimbriae and three bacteriocins and corresponding self-immunity proteins. The plasmid was highly transferable to other E. coli strains, including Shiga-toxin-producing strains, and conferred LHR-dependent heat resistance as well as type 3 fimbriae-dependent biofilm formation capabilities. Selection for and acquisition of this “survival” plasmid by pathogenic organisms, e.g., in food production environments, may pose great concern and emphasizes the need to screen for the presence of LHR genes in isolates. PMID:28439262

  8. Draft Genome Sequences of 10 Bacillus subtilis Strains That Form Spores with High or Low Heat Resistance.

    PubMed

    Berendsen, Erwin M; Wells-Bennik, Marjon H J; Krawczyk, Antonina O; de Jong, Anne; van Heel, Auke; Eijlander, Robyn T; Kuipers, Oscar P

    2016-03-17

    Here, we report the draft genome sequences of 10 isolates of Bacillus subtilis, a spore forming Gram-positive bacterium. The strains were selected from food products and produced spores with either high or low heat resistance. Copyright © 2016 Berendsen et al.

  9. The SpmA/B and DacF proteins of Clostridium perfringens play important roles in spore heat resistance.

    PubMed

    Orsburn, Benjamin; Sucre, Katie; Popham, David L; Melville, Stephen B

    2009-02-01

    Strains of Clostridium perfringens that cause acute food poisoning have been shown to produce spores that are significantly more heat resistant than those of other strains. Previous studies demonstrated that the spore core density and the ratio of spore cortex peptidoglycan relative to the germ cell wall were factors that correlated with the heat resistance of a C. perfringens spore. To further evaluate these relationships, mutant strains of C. perfringens SM101 were constructed with null mutations in dacF, encoding a D,D-carboxypeptidase, and in the spmA-spmB operon, which is involved in spore core dehydration. The dacF mutant was shown to produce less spore cortex peptidoglycan and had a corresponding decrease in spore heat resistance. The spmA-spmB strain produced highly unstable spores with significantly lower core densities and increased heat sensitivity, which were easily destroyed during treatments affecting the spore coat layers. These results support the previous assertion that a threshold core density as well as a high ratio of cortex peptidoglycan relative to the germ cell wall contribute to the formation of a more heat-resistant spore in this species.

  10. Physiological quality and gene expression related to heat-resistant proteins at different stages of development of maize seeds.

    PubMed

    Andrade, T; Von Pinho, E V R; Von Pinho, R G; Oliveira, G E; Andrade, V; Fernandes, J S

    2013-09-13

    We quantified and characterized the expression of heat-resistant proteins during seed development of maize lines with distinct levels of tolerance to high drying temperature. A corn field was planted for multiplication of seeds of different lines, two tolerant and two non-tolerant to high drying temperatures. Harvest of the seeds was carried out at various stages of development and they were then subjected to tests of moisture content, germination, first count of germination, accelerated aging, and cold test. The seeds were stored in a freezer for later analysis of expression of heat-resistant proteins by means of real-time PCR, electrophoresis, and spectrophotometry. We observed that heat-resistant proteins are expressed in a differential manner in seeds from different lines and at different stages of development. The expression of heat-resistant proteins was earlier in lines tolerant to high drying temperatures. Greater germination and vigor values was found for seeds collected at the last stage of development.

  11. Draft Genome Sequences of Two Heat-Resistant Mutant Strains (A52 and B41) of the Photosynthetic Hydrogen-Producing Bacterium Rhodobacter capsulatus

    PubMed Central

    Gokce, Abdulmecit; Cakar, Zeynep Petek; Yucel, Meral; Ozcan, Orhan; Sencan, Sevde; Sertdemir, Ibrahim; Erguner, Bekir; Yuceturk, Betul; Sarac, Aydan; Yuksel, Bayram

    2016-01-01

    The draft genome sequences of two heat-resistant mutant strains, A52 and B41, derived from Rhodobacter capsulatus DSM 1710, and with different hydrogen production levels, are reported here. These sequences may help understand the molecular basis of heat resistance and hydrogen production in R. capsulatus. PMID:27284151

  12. Draft Genome Sequences of Two Heat-Resistant Mutant Strains (A52 and B41) of the Photosynthetic Hydrogen-Producing Bacterium Rhodobacter capsulatus.

    PubMed

    Gokce, Abdulmecit; Cakar, Zeynep Petek; Yucel, Meral; Ozcan, Orhan; Sencan, Sevde; Sertdemir, Ibrahim; Erguner, Bekir; Yuceturk, Betul; Sarac, Aydan; Yuksel, Bayram; Ozturk, Yavuz

    2016-06-09

    The draft genome sequences of two heat-resistant mutant strains, A52 and B41, derived from Rhodobacter capsulatus DSM 1710, and with different hydrogen production levels, are reported here. These sequences may help understand the molecular basis of heat resistance and hydrogen production in R. capsulatus. Copyright © 2016 Gokce et al.

  13. The Heat Resistance of Microbial Cells Represented by D Values Can be Estimated by the Transition Temperature and the Coefficient of Linear Expansion.

    PubMed

    Nakanishi, Koichi; Kogure, Akinori; Deuchi, Keiji; Kuwana, Ritsuko; Takamatsu, Hiromu; Ito, Kiyoshi

    2015-01-01

    We previously developed a method for evaluating the heat resistance of microorganisms by measuring the transition temperature at which the coefficient of linear expansion of a cell changes. Here, we performed heat resistance measurements using a scanning probe microscope with a nano thermal analysis system. The microorganisms studied included six strains of the genus Bacillus or related genera, one strain each of the thermophilic obligate anaerobic bacterial genera Thermoanaerobacter and Moorella, two strains of heat-resistant mold, two strains of non-sporulating bacteria, and one strain of yeast. Both vegetative cells and spores were evaluated. The transition temperature at which the coefficient of linear expansion due to heating changed from a positive value to a negative value correlated strongly with the heat resistance of the microorganism as estimated from the D value. The microorganisms with greater heat resistance exhibited higher transition temperatures. There was also a strong negative correlation between the coefficient of linear expansion and heat resistance in bacteria and yeast, such that microorganisms with greater heat resistance showed lower coefficients of linear expansion. These findings suggest that our method could be useful for evaluating the heat resistance of microorganisms.

  14. Effects of pulp capping materials on fracture resistance of Class II composite restorations.

    PubMed

    Kucukyilmaz, Ebru; Yasa, Bilal; Akcay, Merve; Savas, Selcuk; Kavrik, Fevzi

    2015-01-01

    The aim of this study was to investigate the effect of cavity design and the type of pulp capping materials on the fracture resistance of Class II composite restorations. Sixty freshly extracted, sound molar teeth were selected for the study. A dovetail cavity on the mesio-occlusal and a slot cavity on disto-occlusal surfaces of each tooth were prepared, and the teeth were divided 4 groups which one of them as a control group. The pulp capping materials (TheraCal LC, Calcimol LC, Dycal) applied on pulpo-axial wall of each cavity, and the restoration was completed with composite resin. The teeth were subjected to a compressive load in a universal mechanical testing machine. The surfaces of the tooth and restoration were examined under a stereomicroscope. The data were analyzed using factorial analysis of variance and Tukey's test. For pulp capping materials, the highest fracture load (931.15 ± 203.81 N) and the lowest fracture load (832.28 ± 245.75 N) were calculated for Control and Dycal group, respectively. However, there were no statistically significant differences among all groups (P > 0.05). The fracture load of the dovetail groups was significantly higher than those of the slot cavity groups (P < 0.05). Dovetail cavity design shows better fracture resistance in Class II composite restorations, independent of used or not used pulp capping materials.

  15. Dimensional and material characteristics of direct deposited tool steel by CO II laser

    NASA Astrophysics Data System (ADS)

    Choi, J.

    2006-01-01

    Laser aided direct metalimaterial deposition (DMD) process builds metallic parts layer-by-layer directly from the CAD representation. In general, the process uses powdered metaUmaterials fed into a melt pool, creating fully dense parts. Success of this technology in the die and tool industry depends on the parts quality to be achieved. To obtain designed geometric dimensions and material properties, delicate control of the parameters such as laser power, spot diameter, traverse speed and powder mass flow rate is critical. In this paper, the dimensional and material characteristics of directed deposited H13 tool steel by CO II laser are investigated for the DMD process with a feedback height control system. The relationships between DMD process variables and the product characteristics are analyzed using statistical techniques. The performance of the DMD process is examined with the material characteristics of hardness, porosity, microstructure, and composition.

  16. The Energy Materials in-Situ Laboratory Berlin (EMIL) at BESSY II

    NASA Astrophysics Data System (ADS)

    Follath, R.; Hävecker, M.; Reichardt, G.; Lips, K.; Bahrdt, J.; Schäfers, F.; Schmid, P.

    2013-03-01

    The Helmholtz Center Berlin (HZB) and the Max-Planck Society (MPG) strengthen their research in renewable energies with the implementation of the joint Energy Material in-Situ Lab Berlin (EMIL) at the third generation light source BESSY II. The new facility is dedicated to the in-situ and in-system x-ray analysis of materials and devices for photovoltaic applications, (photo-) catalytic processes, energie conversion and storage. To obtain a comprehensive understanding of the involved materials, spectroscopic methods with x-rays from the soft- up to the hard x-ray regime reveal an almost complete picture of their chemical and electronic properties. The contribution presents the layout of the x-ray beamlines and their performance in terms of photon flux, energy resolution and spot sizes.

  17. 49 CFR 173.202 - Non-bulk packagings for liquid hazardous materials in Packing Group II.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Non-bulk packagings for liquid hazardous materials... Hazardous Materials Other Than Class 1 and Class 7 § 173.202 Non-bulk packagings for liquid hazardous materials in Packing Group II. (a) When § 172.101 of this subchapter specifies that a liquid hazardous...

  18. 49 CFR 173.202 - Non-bulk packagings for liquid hazardous materials in Packing Group II.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Non-bulk packagings for liquid hazardous materials... Hazardous Materials Other Than Class 1 and Class 7 § 173.202 Non-bulk packagings for liquid hazardous materials in Packing Group II. (a) When § 172.101 of this subchapter specifies that a liquid hazardous...

  19. 49 CFR 173.202 - Non-bulk packagings for liquid hazardous materials in Packing Group II.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Non-bulk packagings for liquid hazardous materials... Hazardous Materials Other Than Class 1 and Class 7 § 173.202 Non-bulk packagings for liquid hazardous materials in Packing Group II. (a) When § 172.101 of this subchapter specifies that a liquid hazardous...

  20. Type II strained layer superlattice: a potential infrared sensor material for space

    NASA Astrophysics Data System (ADS)

    Zheng, L.; Tidrow, M. Z.; Novello, A.; Weichel, H.; Vohra, S.

    2008-02-01

    The Missile Defense Agency's Advanced Technology Office is developing advanced passive electro-optical and infrared sensors for future space-based seekers by exploring new infrared detector materials. A Type II strained layer superlattice, one of the materials under development, has shown great potential for space applications. Theoretical results indicate that strained layer superlattice has the promise to be superior to current infrared sensor materials, such as HgCdTe, quantum well infrared photodetectors, and Si:As. Strained layer superlattice-based infrared detector materials combine the advantages of HgCdTe and quantum well infrared photodetectors. The bandgap of strained layer superlattice can be tuned for strong broadband absorption throughout the short-, mid-, long-, and very long wavelength infrared bands. The electronic band structure can be engineered to suppress Auger recombination noise and reduce the tunneling current. The device structures can be easily stacked for multicolor focal plane arrays. The III-V semiconductor fabrication offers the potential of producing low-defect-density, large-format focal plane arrays with high uniformity and high operability. A current program goal is to extend wavelengths to longer than 14 μm for space applications. This paper discusses the advantages of strained layer superlattice materials and describes efforts to improve the material quality, device design, and device processing.

  1. Removal of Cu(II) from leachate using natural zeolite as a landfill liner material.

    PubMed

    Turan, N Gamze; Ergun, Osman Nuri

    2009-08-15

    All hazardous waste disposal facilities require composite liner systems to act as a barrier against migration of contaminated leachate into the subsurface environment. Removal of copper(II) from leachate was studied using natural zeolite. A serial of laboratory systems on bentonite added natural zeolite was conducted and copper flotation waste was used as hazardous waste. The adsorption capacities and sorption efficiencies were determined. The sorption efficiencies increased with increasing natural zeolite ratio. The pseudo-first-order, the pseudo-second-order, Elovich and the intra-particle diffusion kinetic models were used to describe the kinetic data to estimate the rate constants. The second-order model best described adsorption kinetic data. The results indicated that natural zeolite showed excellent adsorptive characteristics for the removal of copper(II) from leachate and could be used as very good liner materials due to its high uptake capacity and the abundance in availability.

  2. Comparison of pressure and heat resistance of Clostridium botulinum and other endospores in mashed carrots.

    PubMed

    Margosch, Dirk; Ehrmann, Matthias A; Gänzle, Michael G; Vogel, Rudi F

    2004-11-01

    Inactivation of bacterial endospores in food requires a combination of pressure and moderate heat. Endospore resistance of seven Clostridium botulinum strains was compared with those of Bacillus spp. (B. cereus, B. subtilis, B. licheniformis, B. smithii, B. amyloliquefaciens) and Thermoanaerobacterium thermosaccharolyticum with respect to pressure (600 to 800 MPa) and temperature (80 to 116 degrees C) treatments in mashed carrots. A large variation was observed in the pressure resistance of C. botulinum spores. Their reduction after treatments with 600 MPa at 80 degrees C for 1 s ranged from more than 5.5 log units to no reduction. Spores of the proteolytic C. botulinum TMW 2.357 exhibited a greater resistance to pressure than spores from all other bacteria examined, with the exception of B. amyloliquefaciens. Heat resistance of spores did not correlate with pressure resistance, either within strains of C. botulinum or when C. botulinum spores were compared with spores of T. thermosaccharolyticum. A quantitative release of dipicolinic acid was observed from C. botulinum spores on combined pressure and temperature treatments only after inactivation of more than 99.999% of the spores. Thus, dipicolinic acid is released by a physicochemical rather than a physiological process. The resistance of spores to combined pressure and temperature treatments correlated with their ability to retain dipicolinic acid. B. amyloliquefaciens, a mesophilic organism that forms highly pressure-resistant spores is proposed as a nonpathogenic target organism for high-pressure process development.

  3. Polyphasic taxonomy of the heat resistant ascomycete genus Byssochlamys and its Paecilomyces anamorphs.

    PubMed

    Samson, R A; Houbraken, J; Varga, J; Frisvad, J C

    2009-06-01

    Byssochlamys and related Paecilomyces strains are often heat resistant and may produce mycotoxins in contaminated pasteurised foodstuffs. A comparative study of all Byssochlamys species was carried out using a polyphasic approach to find characters that differentiate species and to establish accurate data on potential mycotoxin production by each species. Phylogenetic analysis of the ITS region, parts of the beta-tubulin and calmodulin genes, macro- and micromorphological examinations and analysis of extrolite profiles were applied. Phylogenetic analyses revealed that the genus Byssochlamys includes nine species, five of which form a teleomorph, i.e. B. fulva, B. lagunculariae, B. nivea, B. spectabilis and B. zollerniae, while four are asexual, namely P. brunneolus, P. divaricatus, P. formosus and P. saturatus. Among these, B. nivea produces the mycotoxins patulin and byssochlamic acid and the immunosuppressant mycophenolic acid. Byssochlamys lagunculariae produces byssochlamic acid and mycophenolic acid and thus chemically resembles B. nivea. Some strains of P. saturatus produce patulin and brefeldin A, while B. spectabilis (anamorph P. variotii s.s.) produces viriditoxin. Some micro- and macromorphological characters are valuable for identification purposes, including the shape and size of conidia and ascospores, presence and ornamentation of chlamydospores, growth rates on MEA and CYA and acid production on CREA. A dichotomous key is provided for species identification based on phenotypical characters.

  4. Mechanically alloyed Ni-base alloys for heat-resistant applications

    SciTech Connect

    Wilson, R.K.; Fischer, J.J.

    1995-12-31

    INCONEL alloys MA 754 and MA 758 are nickel-base oxide dispersion-strengthened (ODS) alloys made by mechanical alloying (MA). Commercial use of Ma Ni-base alloys to date has been predominantly in aerospace applications of alloy MA 754 as turbine engine vanes. Both alloys are suitable for industrial heat treating components and other heat resistant alloy applications. Field trials and commercial experience in such applications of MA alloys are being gained while high temperature property characterization and new product form development continue. Hot isostatic pressing (HIP) is the standard consolidation method for billets from which large bar and plate are produced for industrial applications of MA. This paper describes production of standard mill shapes from HIP billets, and it presents information on current and potential uses of MA alloys in applications such as: skid rails for use in high temperature walking beam furnaces, heat treating furnace components, components for handling molten glass, and furnace tubes. The paper includes comparison of the properties obtained in alloy MA 754 (20% Cr) and alloy MA 758 (30% Cr).

  5. New candidate genes for heat resistance in Drosophila melanogaster are regulated by HSF.

    PubMed

    Jensen, Louise Toft; Nielsen, Morten Muhlig; Loeschcke, Volker

    2008-01-01

    The cellular heat stress response is well studied in Drosophila in respect to the role of heat shock proteins (Hsp). Hsps are molecular chaperones, highly expressed during and after exposure to numerous stress types. Hsps are all regulated by a common transcription factor, the heat shock factor (HSF), and it is known that HSF is controlling other, so far uncharacterised, heat-responsive genes. In this study, we investigate whether novel candidate genes for heat resistance, identified by microarray experiments, are regulated by HSF. The microarray experiments recently identified several strongly upregulated genes in response to a short, non-lethal heat treatment in Drosophila melanogaster. To test whether or not a subset of these genes are HSF-induced, we studied 11 currently unannotated genes using quantitative polymerase chain reaction on HSF mutant flies with a non-functional HSF at elevated temperatures. We found indication of HSF regulation in most of the studied genes, suggesting a role of these unknown genes in heat tolerance. Surprisingly, some of the genes seemed to be upregulated independent of HSF function. The high induction in response to heat, which mimics the expression profile of Hsps, implies a role in the cellular heat response of these genes as well.

  6. Failure Mechanism of a Stellite Coating on Heat-Resistant Steel

    NASA Astrophysics Data System (ADS)

    Wang, Dong; Zhao, Haixing; Wang, Huang; Li, Yuyan; Liu, Xia; He, Guo

    2017-09-01

    The Stellite 21 coating on the heat-resistant steel X12CrMoWVNbN10-1-1 (so-called COSTE) used in a steam turbine valve was found to be fatigue broken after service at around 873 K (600 °C) for about 8 years. In order to investigate the failure mechanism, a fresh Stellite 21 coating was also prepared on the same COSTE steel substrate by using the similar deposition parameters for comparison. It was found that the Stellite 21 coating was significantly diluted by the steel, resulting in a thin Fe-rich layer in the coating close to the fusion line. Such high Fe concentration together with the incessant Fe diffusion from the steel substrate to the coating during the service condition (about 873 K (600 °C) for long time) induced the eutectoid decomposition of the fcc α-Co(Fe,Cr,Mo) solid solution, forming an irregular eutectoid microstructure that was composed of the primitive cubic α'-FeCo(Cr,Mo) phase and the tetragonal σ-CrCo(Fe,Mo) phase. The brittle nature of such α'/ σ eutectoid microstructure contributed to the fatigue fracture of the Stellite 21 coating, resulting in an intergranular rupture mode.

  7. Response of Two Heat Shock Genes to Selection for Knockdown Heat Resistance in Drosophila Melanogaster

    PubMed Central

    McColl, G.; Hoffmann, A. A.; McKechnie, S. W.

    1996-01-01

    To identify genes involved in stress resistance and heat hardening, replicate lines of Drosophila melanogaster were selected for increased resistance to knockdown by a 39° heat stress. Two selective regimes were used, one with and one without prior hardening. Mean knockdown times were increased from ~5 min to >20 min after 18 generations. Initial realized heritabilities were as high as 10% for lines selected without hardening, and crosses between lines indicated simple additive gene effects for the selected phenotypes. To survey allelic variation and correlated selection responses in two candidate stress genes, hsr-omega and hsp68, we applied denaturing gradient gel electrophoresis to amplified DNA sequences from small regions of these genes. After eight generations of selection, allele frequencies at both loci showed correlated responses for selection following hardening, but not without hardening. The hardening process itself was associated with a hsp68 frequency change in the opposite direction to that associated with selection that followed hardening. These stress loci are closely linked on chromosome III, and the hardening selection established a disequilibrium, suggesting an epistatic effect on resistance. The data indicate that molecular variation in both hsr-omega and hsp68 contribute to natural heritable variation for hardened heat resistance. PMID:8844150

  8. High-Temperature Low-Cycle Fatigue Property of Heat-Resistant Ductile-Cast Irons

    NASA Astrophysics Data System (ADS)

    Kim, Yoon-Jun; Jang, Ho; Oh, Yong-Jun

    2009-09-01

    This study examined the high-temperature degradation behavior of two types of heat-resistant Si-Mo ductile cast iron (Fe-3.4C-3.7Si-0.4Mo and Fe-3.1C-4.5Si-1.0Mo) with particular attention paid to the mechanical properties and overall oxidation resistance. Tension and low-cycle fatigue properties were examined at 600 °C and 800 °C. The mechanical tests and metallographic and fractographic analyses showed that cast iron containing higher Si and Mo contents had a higher tensile strength and longer fatigue life at both temperatures than cast iron with lower levels due to the phase transformations of pearlite and carbide. The Coffin-Manson type equation was used to assess the fatigue mechanism suggesting that the higher Si-Mo alloy was stronger but less ductile than the lower Si-Mo alloy at 600 °C. However, similar properties for both alloys were observed at 800 °C because of softening and oxidation effects. Analysis of the isothermal oxidation behavior at those temperatures showed that mixed Fe2SiO4 layers were formed and the resulting scaling kinetics was much faster for low Si-Mo containing iron. With increasing temperature, subsurface degradation such as decarburization, voids, and cracks played a significant role in the overall oxidation resistance.

  9. Structural transformations in heat-resistant protective coatings on nickel alloys

    SciTech Connect

    Veksler, Yu.G.; Lesnikov, V.P.; Paleeva, S.Ya.; Lesnikova, E.G.; Myal'nitsa, G.F.

    1987-09-01

    In this work a comprehensive metallophysical study was carried out for two aluminosilicide slip coatings of the systems Al-Si and Al-Nb-Si and an electron-beam Co-Cr-Al-Y coating on alloy EP-539 (17...19% Cr, 4...6% Co, 2.5...4% W, 4.5...6.5% Mo, 2...3% Ti, 3...4% Al, 1.4...2% Nb, balance Ni) after high-temperature testing. The protective properties of the coatings were evaluated from the results of laboratory tests for heat resistance at 1000/sup 0/C in the combustion products of diesel fuel with added sulfur at 970, 1000, and 1060/sup 0/C for 100 h and after full-scale tests for 150, 250, 400, and 700 h. Metallographic, hardness, x-ray, and micro x-ray studies of the coating were carried out. Layer-by-layer phase composition and the lattice spacing of the main phases were determined. X-ray analysis was carried out in an a DRON-1 diffractometer in copper K/sub ..-->../-radiation, and x-ray microanalysis was carried out in a MS-46 Cameca microanalyzer

  10. Tracking heat-resistant, cold-thriving fluid milk spoilage bacteria from farm to packaged product.

    PubMed

    Huck, J R; Sonnen, M; Boor, K J

    2008-03-01

    Control of psychrotolerant endospore-forming spoilage bacteria, particularly Bacillus and Paenibacillus spp., is economically important to the dairy industry. These microbes form endospores that can survive high-temperature, short-time pasteurization; hence, their presence in raw milk represents a major potential cause of milk spoilage. A previously developed culture-dependent selection strategy and an rpoB sequence-based subtyping method were applied to bacterial isolates obtained from environmental samples collected on a New York State dairy farm. A total of 54 different rpoB allelic types putatively identified as Bacillus (75% of isolates), Paenibacillus (24%), and Sporosarcina spp. (1%) were identified among 93 isolates. Assembly of a broader data set, including 93 dairy farm isolates, 57 raw milk tank truck isolates, 138 dairy plant storage silo isolates, and 336 pasteurized milk isolates, identified a total of 154 rpoB allelic types, representing an extensive diversity of Bacillus and Paenibacillus spp. Our molecular subtype data clearly showed that certain endospore-forming bacterial subtypes are present in the dairy farm environment as well as in the processing plant. The potential for entry of these ubiquitous heat-resistant spoilage organisms into milk production and processing systems, from the dairy farm to the processing plant, represents a considerable challenge that will require a comprehensive farm-to-table approach to fluid milk quality.

  11. Failure Mechanism of a Stellite Coating on Heat-Resistant Steel

    NASA Astrophysics Data System (ADS)

    Wang, Dong; Zhao, Haixing; Wang, Huang; Li, Yuyan; Liu, Xia; He, Guo

    2017-07-01

    The Stellite 21 coating on the heat-resistant steel X12CrMoWVNbN10-1-1 (so-called COSTE) used in a steam turbine valve was found to be fatigue broken after service at around 873 K (600 °C) for about 8 years. In order to investigate the failure mechanism, a fresh Stellite 21 coating was also prepared on the same COSTE steel substrate by using the similar deposition parameters for comparison. It was found that the Stellite 21 coating was significantly diluted by the steel, resulting in a thin Fe-rich layer in the coating close to the fusion line. Such high Fe concentration together with the incessant Fe diffusion from the steel substrate to the coating during the service condition (about 873 K (600 °C) for long time) induced the eutectoid decomposition of the fcc α-Co(Fe,Cr,Mo) solid solution, forming an irregular eutectoid microstructure that was composed of the primitive cubic α'-FeCo(Cr,Mo) phase and the tetragonal σ-CrCo(Fe,Mo) phase. The brittle nature of such α'/σ eutectoid microstructure contributed to the fatigue fracture of the Stellite 21 coating, resulting in an intergranular rupture mode.

  12. Heat resistance of viable but non-culturable Escherichia coli cells determined by differential scanning calorimetry.

    PubMed

    Castro-Rosas, Javier; Gómez-Aldapa, Carlos Alberto; Villagómez Ibarra, José Roberto; Santos-López, Eva María; Rangel-Vargas, Esmeralda

    2017-10-16

    Several reports have suggested that the viable but non-culturable (VBNC) state is a resistant form of bacterial cells that allows them to remain in a dormant form in the environment. Nevertheless, studies on the resistance of VBNC bacterial cells to ecological factors are limited, mainly because techniques that allow this type of evaluation are lacking. Differential scanning calorimetry (DSC) has been used to study the thermal resistance of culturable bacteria but has never been used to study VBNC cells. In this work, the heat resistance of Escherichia coli cells in the VBNC state was studied using the DSC technique. The VBNC state was induced in E. coli ATCC 25922 by suspending bacterial cells in artificial sea water, followed by storage at 3 ± 2°C for 110 days. Periodically, the behaviour of E. coli cells was monitored by plate counts, direct viable counts and DSC. The entire bacterial population entered the VBNC state after 110 days of storage. The results obtained with DSC suggest that the VBNC state does not confer thermal resistance to E. coli cells in the temperature range analysed here. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Heat shock applied early in sporulation affects heat resistance of Bacillus megaterium spores.

    PubMed

    Sedlák, M; Vinter, V; Adamec, J; Vohradský, J; Voburka, Z; Chaloupka, J

    1993-12-01

    Cells of Bacillus megaterium 27 were challenged by a 30-min heat shock at 45 degrees C during various sporulation stages and then shifted back to a temperature permissive for sporulation (27 degrees C), at which they developed spores. Heat shock applied at 120 min after the end of the exponential phase induced synthesis of heat shock proteins (HSPs) in the sporangia and delayed the inactivation of spores at 85 degrees C. Several HSPs, mainly HSP 70, could be detected in the cytoplasm of these spores. An analogous HSP, the main HSP induced by increased temperature during growth, belongs to the GroEL group according to its N-terminal sequence. The identity of this protein was confirmed by Western blot (immunoblot) analysis with polyclonal antibodies against B. subtilis GroEL. Sporangia treated by heat shock immediately or 240 min after exponential phase also synthesized HSPs, but none of them could be detected in the spores in an appreciable amount. These spores showed only a slightly increased heat resistance.

  14. Novel Solar Energy Conversion Materials by Design of Mn(II) Oxides

    SciTech Connect

    Lany, S.; Peng, H.; Ndione, P.; Zakutayev, A.; Ginley, D. S.

    2013-01-01

    Solar energy conversion materials need to fulfill simultaneously a number of requirements in regard of their band-structure, optical properties, carrier transport, and doping. Despite their desirable chemical properties, e.g., for photo-electrocatalysis, transition-metal oxides usually do not have desirable semiconducting properties. Instead, oxides with open cation d-shells are typically Mott or charge-transfer insulators with notoriously poor transport properties, resulting from large effective electron/hole masses or from carrier self-trapping. Based on the notion that the electronic structure features (p-d interaction) supporting the p-type conductivity in d10 oxides like Cu2O and CuAlO2 occurs in a similar fashion also in the d5 (high-spin) oxides, we recently studied theoretically the band-structure and transport properties of the prototypical binary d5 oxides MnO and Fe2O3 [PRB 85, 201202(R)]. We found that MnO tends to self-trap holes by forming Mn+III, whereas Fe2O3 self-traps electrons by forming Fe+II. However, the self-trapping of holes is suppressed by when Mn is tetrahedrally coordinated, which suggests specific routes to design novel solar conversion materials by considering ternary Mn(II) oxides or oxide alloys. We are presenting theory, synthesis, and initial characterization for these novel energy materials.

  15. The EBR-II materials-surveillance program. 4: Results of SURV-4 and SURV-6

    SciTech Connect

    Ruther, W.E.; Hayner, G.O.; Carlson, B.G.; Ebersole, E.R.; Allen, T.R.

    1998-01-01

    In March of 1965, a set of surveillance (SURV) samples was placed in the EBR-II reactor to determine the effect of irradiation, thermal aging, and sodium corrosion on reactor materials. Eight subassemblies were placed into row 12 positions of EBR-II to determine the effect of irradiation at 370 C. Two subassemblies were placed into the primary sodium basket to determine the effect of thermal aging at 370 C. For both the irradiated and thermally aged samples, one half of all samples were exposed to primary system sodium while one half were sealed in capsules with a helium atmosphere. Fifteen different structural materials were tested in the SURV program. In addition to the fifteen types of metal samples, graphite blocks were irradiated in the SURV subassemblies to determine the effect of irradiation on the graphite neutron shield. In this report, the properties of these materials irradiated at 370 C to a total fluence of 2.2 x 10{sup 22} n/cm{sup 2} (over 2,994 days) are compared with those of similar specimens thermally aged at 370 C for 2,994 days in the storage basket of the reactor. The properties analyzed were weight, density, microstructure, hardness, tensile and yield strength, impact strength, and creep.

  16. On the heat flux vector for flowing granular materials--part II: derivation and special cases

    SciTech Connect

    Massoudi, Mehrdad

    2006-09-10

    Heat transfer plays a major role in the processing of many particulate materials. The heat flux vector is commonly modelled by the Fourier's law of heat conduction and for complex materials such as non-linear fluids, porous media, or granular materials, the coefficient of thermal conductivity is generalized by assuming that it would depend on a host of material and kinematical parameters such as temperature, shear rate, porosity or concentration, etc. In Part I, we will give a brief review of the basic equations of thermodynamics and heat transfer to indicate the importance of the modelling of the heat flux vector. We will also discuss the concept of effective thermal conductivity (ETC) in granular and porous media. In Part II, we propose and subsequently derive a properly frame-invariant constitutive relationship for the heat flux vector for a (single phase) flowing granular medium. Standard methods in continuum mechanics such as representation theorems and homogenization techniques are used. It is shown that the heat flux vector in addition to being proportional to the temperature gradient (the Fourier's law), could also depend on the gradient of density (or volume fraction), and D (the symmetric part of the velocity gradient) in an appropriate manner. The emphasis in this paper is on the idea that for complex non-linear materials it is the heat flux vector which should be studied; obtaining or proposing generalized form of the thermal conductivity is not always appropriate or sufficient.

  17. Alkali metal protective garment and composite material

    SciTech Connect

    Ballif, J.L.; Yuan, W.W.

    1980-09-16

    A protective garment and composite material providing satisfactory heat resistance and physical protection for articles and personnel exposed to hot molten alkali metals, such as sodium are described. Physical protection is provided by a continuous layer of nickel foil. Heat resistance is provided by an underlying backing layer of thermal insulation. Overlying outer layers of fireproof woven ceramic fibers are used to protect the foil during storage and handling.

  18. Alkali metal protective garment and composite material

    DOEpatents

    Ballif, III, John L.; Yuan, Wei W.

    1980-01-01

    A protective garment and composite material providing satisfactory heat resistance and physical protection for articles and personnel exposed to hot molten alkali metals, such as sodium. Physical protection is provided by a continuous layer of nickel foil. Heat resistance is provided by an underlying backing layer of thermal insulation. Overlying outer layers of fireproof woven ceramic fibers are used to protect the foil during storage and handling.

  19. Study of the influence of sporulation conditions on heat resistance of Geobacillus stearothermophilus used in the development of biological indicators for steam sterilization.

    PubMed

    Guizelini, Belquis P; Vandenberghe, Luciana P S; Sella, Sandra Regina B R; Soccol, Carlos Ricardo

    2012-12-01

    Biological indicators are important tools in infection control via sterilization process monitoring. The use of a standardized spore crop with a well-defined heat resistance will guarantee the quality of a biological indicator. Ambient factors during sporulation can affect spore characteristics and properties, including heat resistance. The aim of this study is to evaluate the main sporulation factors responsible for heat resistance in Geobacillus stearothermophilus, a useful biological indicator for steam sterilization. A sequence of a three-step optimization of variables (initial pH, nutrient concentration, tryptone, peptone, beef extract, yeast extract, manganese sulfate, magnesium sulfate, calcium chloride and potassium phosphate) was carried out to screen those that have a significant influence on heat resistance of produced spores. The variable exerting greatest influence on G. stearothermophilus heat resistance during sporulation was found to be the initial pH. Lower nutrient concentration and alkaline pH around 8.5 tended to enhance decimal reduction time at 121 °C (D(121°C)). A central composite design enabled a fourfold enhancement in heat resistance, and the model obtained accurately describes positive pH and negative manganese sulfate concentration influence on spore heat resistance.

  20. Adhesive ability of a heat-resistant double-chain polymer and the strength of CFRP based on it

    NASA Astrophysics Data System (ADS)

    Gorbatkina, Yu. A.; Ivanova-Mumjieva, V. G.; Kuperman, A. M.; Ponomarev, I. I.; Sidorenko, V. I.

    2008-07-01

    The adhesive ability of a heat-resistant polyiminoquinazolindione (PIQD) binder, based on a double-chain polymer, and the physicomechanical characteristics of unidirectional CFRPs made with it are investigated. It is shown that, at room temperature, the strength of model adhesive joints (PIQD-steel wire) and of the CFRPs in shear and bending is rather low — about half of that of similar specimens based on an epoxy binder. At the same time, all their mechanical characteristics, to a large measure (50%), are retained at temperatures up to 450°C, which considerably exceeds the heat resistance of all polymer matrices used at the present time. The elastic modulus of the CFRPs in bending practically remains the same up to 450°C.

  1. Formation of high heat resistant coatings by using gas tunnel type plasma spraying.

    PubMed

    Kobayashi, A; Ando, Y; Kurokawa, K

    2012-06-01

    Zirconia sprayed coatings are widely used as thermal barrier coatings (TBC) for high temperature protection of metallic structures. However, their use in diesel engine combustion chamber components has the long run durability problems, such as the spallation at the interface between the coating and substrate due to the interface oxidation. Although zirconia coatings have been used in many applications, the interface spallation problem is still waiting to be solved under the critical conditions such as high temperature and high corrosion environment. The gas tunnel type plasma spraying developed by the author can make high quality ceramic coatings such as Al2O3 and ZrO2 coating compared to other plasma spraying method. A high hardness ceramic coating such as Al2O3 coating by the gas tunnel type plasma spraying, were investigated in the previous study. The Vickers hardness of the zirconia (ZrO2) coating increased with decreasing spraying distance, and a higher Vickers hardness of about Hv = 1200 could be obtained at a shorter spraying distance of L = 30 mm. ZrO2 coating formed has a high hardness layer at the surface side, which shows the graded functionality of hardness. In this study, ZrO2 composite coatings (TBCs) with Al2O3 were deposited on SS304 substrates by gas tunnel type plasma spraying. The performance such as the mechanical properties, thermal behavior and high temperature oxidation resistance of the functionally graded TBCs was investigated and discussed. The resultant coating samples with different spraying powders and thickness are compared in their corrosion resistance with coating thickness as variables. Corrosion potential was measured and analyzed corresponding to the microstructure of the coatings. High Heat Resistant Coatings, Gas Tunnel Type Plasma Spraying, Hardness,

  2. Development of 3D modeling technology for manufacturing finned ribbons from heat-resistant steels

    NASA Astrophysics Data System (ADS)

    Lyashkov, A. A.; Vasil'ev, E. V.; Popov, A. Y.

    2017-06-01

    The process of shaping a workpiece by a tool using the rolling method is, from the geometric point of view, a process of interaction of two conjugate surfaces. The technology of rolling finned stainless steel ribbons is close to the technology of shaping details by cutting. However, the problems of its practical implementation in the well-known papers analyzing this issue are practically not considered. As a result of the analysis of conjugate surfaces profiling methods in relation to the problem, it was concluded that it seems urgent to develop a methodology for the formation of corrugated ribbon based on 3D modeling use. The implementation of this methodology includes the creation of solid models of the product and the tool, as well as computer simulation of their shaping processes using rolling method. So, at the first stage, a 3D model of finned ribbon was developed, which was then used to produce a profile of a rolling tool. The modeling of this profile was carried out on the basis of the proposed software package in the CAD environment. The created theoretical model of the tool profile was replaced from the technological point of view by a rectilinear profile. To carry out the analysis of the obtained results, the inverse shaping problem was solved - according to the corrected profile of the tool, real profile of the corrugated ribbon is obtained. Computer modeling of extruded volumes in the process of shaping was performed. The analysis of qualitative and quantitative parameters of the extruded volumes made it possible to give recommendations on setting the increment of the tool motion parameter. Based on the results of the studies, profile parameters of the roller are assigned for its practical implementation. The proposed methodology, based on 3D-modeling, allowed to develop a technology for manufacturing finned ribbons from heat-resistant steels by rolling with high productivity, accuracy and stability of the sizes obtained.

  3. Efficacy of Traditional Almond Decontamination Treatments and Electron Beam Irradiation against Heat-Resistant Salmonella Strains.

    PubMed

    Cuervo, Mary P; Lucia, Lisa M; Castillo, Alejandro

    2016-03-01

    Two outbreaks of salmonellosis were linked to the consumption of raw almonds from California in 2001 and 2004. As a result, federal regulations were developed, which mandate that all almonds grown in California must be treated with a process that results in a 4-log reduction of Salmonella. Because most of the technologies approved to treat almonds rely on the application of heat to control Salmonella, an evaluation of alternative technologies for inactivating heat-resistant Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W was needed. In this study, almonds were inoculated with Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W and then treated with an electron beam (e-beam) or by blanching or oil roasting. The irradiation D10-values for Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W treated with e-beam were 0.90 and 0.72 kGy, respectively. For heat treatments, thermal D10-values for Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W strains were 15.6 and 12.4 s, respectively, when subjected to blanching at 88°C and 13.2 and 10.9 s, respectively, when roasted in oil at 127 ± 2°C. No significant differences in irradiation and thermal treatment results were observed between Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W (P > 0.05), indicating that e-beam irradiation may be a feasible technology for reducing Salmonella in almonds. However, the sensory changes resulting from irradiating at the doses used in this study must be evaluated before e-beam irradiation can be used as a nonthermal alternative for decontamination of almonds.

  4. Sulfidation/carburization resistance of several heat-resistant alloys at 900 C

    SciTech Connect

    Harper, M.A.; Barnes, J.E.

    1998-12-31

    The results of high temperature sulfidation plus carburization testing on seven different commercial heat resistant alloys are reported in this paper. The test environment consisted of a H{sub 2}-25vol%CH{sub 4}-14.8N{sub 2}-4CO-0.6H{sub 2}S gas at 1650 F (9OO C) and the time of exposure was 500 hours. Relatively thick, mixed sulfide scales were formed on all of the alloys tested. Also, internal carburization occurred within all of the alloys. The use of x-ray diffraction allowed the phases constituting the scales to be identified, and these phases were in agreement with previous work published on the testing of various alloys in high temperature low oxygen activity, high sulfur and carbon activity atmospheres. Using metal loss (i.e. the reduction in sample thickness) plus internal attack (internal sulfidation plus internal carburization) as a performance criterion, an alloy with a nominal composition of Ni-29wt%Co-28Cr-2.75Si performed the best, showing 28 mils (0.71 mm) of attack, and an alloy with a nominal composition of Fe-20wt%Ni-25Cr performed the worst, being totally consumed by the test (>125 mils/3.18 mm of attack). The sulfidation plus carburization resistance of the Ni-Co-Cr-Si alloy is attributed to its high chromium plus silicon content, both of which are known to be beneficial in sulfidizing and carburizing environments, and its low iron/high nickel content, which results in a low solubility and diffusivity of carbon in the matrix.

  5. Study of the adsorption of mercury (II) on lignocellulosic materials under static and dynamic conditions.

    PubMed

    Arias Arias, Fabian E; Beneduci, Amerigo; Chidichimo, Francesco; Furia, Emilia; Straface, Salvatore

    2017-08-01

    WHO has declared mercury as one of the most dangerous pollutants for human health. Unfortunately, several cases of rivers and aquifers contaminated by mercury inevitably poses the problem on how to remediate them. Considerable efforts are being addressed to develop cost-effective methodologies, among which the use of low-cost adsorbing materials. In this paper, the adsorption performances of an alternative lignocellulosic material derived from the Spanish broom plant, are presented. This plant is widely diffused in the world and its usage for Hg(II) removal from water in real working conditions requires only minimal pretreatment steps. A thoroughly investigation on the kinetics and thermodynamics of Hg(II) adsorption on Spanish broom is presented, by using Hg(II) polluted aqueous solutions specifically prepared in order to simulate typical groundwater conditions. Several batch experiments, under static conditions, were carried out in order to evaluate the effect of pH, contact time, adsorbent dosage, initial concentration, temperature. A maximum adsorption capacity of 20 mg L(-1) can be obtained at pH 5, following a pseudo second order kinetics. Moreover, adsorption experiments in dynamic conditions were carried out using Spanish broom filters. Interestingly, a systematic, unconventional double S-shape breakthrough curve was observed under different experimental conditions, revealing the occurrence of two adsorption processes with different time scales. This behavior has been fitted by a bimodal Thomas model which, unlike the single Thomas fitting, gives satisfactory results with the introduction of a new parameter related to the fraction of surface active sites involved in the adsorption processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Genetic Characterization of the Exceptionally High Heat Resistance of the Non-toxic Surrogate Clostridium sporogenes PA 3679

    PubMed Central

    Butler, Robert R.; Schill, Kristin M.; Wang, Yun; Pombert, Jean-François

    2017-01-01

    Clostridium sporogenes PA 3679 is a non-toxic endospore former that is widely used as a surrogate for Clostridium botulinum by the food processing industry to validate thermal processing strategies. PA 3679 produces spores of exceptionally high heat resistance without botulinum neurotoxins, permitting the use of PA 3679 in inoculated pack studies while ensuring the safety of food processing facilities. To identify genes associated with this heat resistance, the genomes of C. sporogenes PA 3679 isolates were compared to several other C. sporogenes strains. The most significant difference was the acquisition of a second spoVA operon, spoVA2, which is responsible for transport of dipicolinic acid into the spore core during sporulation. Interestingly, spoVA2 was also found in some C. botulinum species which phylogenetically cluster with PA 3679. Most other C. sporogenes strains examined both lack the spoVA2 locus and are phylogenetically distant within the group I Clostridium, adding to the understanding that C. sporogenes are dispersed C. botulinum strains which lack toxin genes. C. sporogenes strains are thus a very eclectic group, and few strains possess the characteristic heat resistance of PA 3679. PMID:28421047

  7. Identification and characterization of a heat-resistant protease from Serratia liquefaciens isolated from Brazilian cold raw milk.

    PubMed

    Machado, Solimar Gonçalves; Heyndrickx, Marc; De Block, Jan; Devreese, Bart; Vandenberghe, Isabel; Vanetti, Maria Cristina Dantas; Van Coillie, Els

    2016-04-02

    The cold storage of raw milk before heat treatment in dairy industry promotes the growth of psychrotrophic microorganisms, which are known for their ability to produce heat-resistant proteolytic enzymes. Although Pseudomonas is described as the main causative genus for high proteolytic spoilage potential in dairy products, Serratia liquefaciens secretes proteases and may be found in raw milk samples as well. However, at the present there is no information about the proteolytic spoilage potential of S. liquefaciens in milk after heat-treatment. The main aim of this research was to assess the proteolytic spoilage potential of S. liquefaciens isolated from Brazilian raw milk and to characterize the involved protease. S. liquefaciens was shown to secrete one heat-resistant spoilage metalloprotease of, approximately, 52 kDa encoded by the ser2 gene. The heat-resistance of Ser2 was similar to the aprX encoded metalloprotease produced by Pseudomonas. Although the ser2 gene was detected in all S. liquefaciens isolates tested in this study, the proteolytic activity of the isolates in milk was highly heterogeneous. Since nucleotide and deduced amino acid sequences of ser2 of all tested isolates are identical, this heterogeneity may be attributed to differences in enzyme expression levels or post-translational modifications.

  8. Sporulation environment of emetic toxin-producing Bacillus cereus strains determines spore size, heat resistance and germination capacity.

    PubMed

    van der Voort, M; Abee, T

    2013-04-01

    Heat resistance, germination and outgrowth capacity of Bacillus cereus spores in processed foods are major factors in causing the emetic type of gastrointestinal disease. In this study, we aim to identify the impact of different sporulation conditions on spore properties of emetic toxin-producing B. cereus strains. Spore properties of eight different emetic toxin-producing strains were tested, with spores produced in five different sporulation conditions: aerated liquid cultures, air-liquid biofilms, 1.5% agar plates, 0.75% agar plates and swarming colonies. Model food studies revealed spores from emetic toxin-producing strains to germinate efficiently on meat broth- and milk-based agar plates, whereas germination on rice-based agar plates was far less efficient. Notably, spores of all strains germinated efficiently when 0.1% meat broth was added to the rice plates. Analysis of spores derived from different environments revealed large diversity and showed biofilm spores for the strains tested to be the largest in size, the most heat resistant and with the lowest germination capacity. Sporulation in complex conditions such as biofilms and surface swarming colonies increases heat resistance and dormancy of spores. The results obtained imply the importance of sporulation conditions on spore properties of emetic toxin-producing B. cereus strains, as occur for instance in food processing. © 2012 The Society for Applied Microbiology.

  9. Occurrence of molds on laminated paperboard for aseptic packaging, selection of the most hydrogen peroxide- and heat-resistant isolates and determination of their thermal death kinetics in sterile distilled water.

    PubMed

    Delgado, Denise Aparecida; de Souza Sant'ana, Anderson; de Massaguer, Pilar Rodriguez

    2012-07-01

    This study aimed at enumerating molds (heat-labile and heat-resistant) on the surface of paperboard material to be filled with tomato pulps through an aseptic system and at determining the most heat- and hydrogen peroxide-resistant strains. A total of 118 samples of laminated paperboard before filling were collected, being 68 before and 50 after the hydrogen peroxide bath. Seven molds, including heat-resistant strains (Penicillium variotii and Talaromyces flavus) with counts ranging between 0.71 and 1.02 CFU/cm(2) were isolated. P. variotii was more resistant to hydrogen peroxide than T. flavus and was inactivated after heating at 85 °C/15 min. When exposed to 35 % hydrogen peroxide at 25 °C, T. flavus (F5E2) and N. fischeri (control) were less resistant than P. variotti (F1A1). P. citrinum (F7E2) was shown to be as resistant as P. variotti. The D values (the time to cause one logarithmic cycle reduction in a microbial population at a determined temperature) for spores of P. variotii (F1A1) and N. fischeri (control) with 4 months of age at 85 and 90 °C were 3.9 and 4.5 min, respectively. Although the contamination of packages was low, the presence of heat- and chemical-resistant molds may be of concern for package sterility and product stability during shelf-life. To our knowledge, this is the first report that focuses on the isolation of molds, including heat-resistant ones, contaminating paperboard packaging material and on estimating their resistance to the chemical and physical processes used for packaging sterilization.

  10. Adsorption of Cd(II) and Pb(II) by a novel EGTA-modified chitosan material: kinetics and isotherms.

    PubMed

    Zhao, Feiping; Repo, Eveliina; Yin, Dulin; Sillanpää, Mika E T

    2013-11-01

    In this study, a novel adsorbent was synthesized by functionalizing chitosan with ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA) ligands. The adsorption capability of EGTA-modified chitosan was investigated by the removal of Cd(II) and Pb(II) from aqueous solutions. The adsorption and regeneration studies were performed by batch techniques. The effects of pH, contact time, and initial metal concentration were studied. Metal uptake by EGTA-chitosan was 0.74 mmol g(-1) for Cd(II) and 0.50 mmol g(-1) for Pb(II). The adsorption mechanism, that the adsorbent formed octahedral chelate structures with bivalent metal ions, was proposed tentatively based on the experimental results of FTIR and the theoretically calculated data of point charges. The kinetics of Cd(II) and Pb(II) on EGTA-chitosan complied with the pseudo-second-order model and the adsorption rate was also influenced by intra-particle diffusion. BiLangmuir isotherm model was well fitted to the experimental data of one-component adsorption suggesting the surface heterogeneity of the novel adsorbent. The extended form of the BiLangmuir model was tested for the modeling of two-component adsorption equilibrium of Cd(II) and Pb(II) on EGTA-chitosan. In the two-component solution, both competitive adsorption and positive synergy of chelation between metal ions occurred and the novel adsorbent showed higher affinity toward Cd(II). Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Effect of pre-treatment and supporting media on Ni(II), Cu(II), Al(III) and Fe(III) sorption by plant root material.

    PubMed

    Araújo, G C L; Lemos, S G; Ferreira, A G; Freitas, H; Nogueira, A R A

    2007-06-01

    In this work Paspalum notatum root material was used to elucidate the influence of acid leaching pre-treatment and of sorption medium on metal adsorption. Ground P. notatum root was leached with 0.14M HNO(3). Leached root material (LRM) and non-leached root material (NLRM) were employed to flow sorption of Ni(II), Cu(II), Al(III) and Fe(III) in 0.5M CH(3)COONH(4) medium at pH 6.5. For LRM the sorption was also studied in 0.5M KNO(3) medium. The acid pre-treatment increased the sorption capacity (SC) for all ions studied. For the KNO(3) medium, Cu(II) and Fe(III) sorption was higher than in CH(3)COONH(4) and the type of the Ni(II) isotherm's model changed. The Freundlich model was the most representative isotherm model to describe metallic ions sorption. The (1)H NMR spectra showed differences between LRM and NLRM and the acid-basic potentiometric titration elucidated that acid-leaching procedure affected the root material sorption sites once only two predominant sorption sites were found for LRM (phenolic and amine, both able cations sorption) and five sorption sites (two carboxylic, amine and two phenolic) were founded for NLRM.

  12. Communications for Lifelong Success I and II (Tech Prep English I and II). Pilot Test Materials for Pendleton High School, Pendleton, South Carolina. Draft.

    ERIC Educational Resources Information Center

    Turlington, Anita; And Others

    These instructional materials include six supplementary units for Tech Prep English I (grade 9) and six assignments for Tech Prep English II (grade 10). The Tech Prep English I units have these components: unit objectives, introduction, and follow-up exercises. Topics include goal setting, problem solving and decision making, listening and reading…

  13. Modifications in membrane fatty acid composition of Salmonella typhimurium in response to growth conditions and their effect on heat resistance.

    PubMed

    Alvarez-Ordóñez, Avelino; Fernández, Ana; López, Mercedes; Arenas, Ricardo; Bernardo, Ana

    2008-04-30

    The effects of growth temperature (in the range 10-45 degrees C) and acidification up to pH 4.5 of the culture medium (Brain Heart Infusion, BHI) with different organic acids (acetic, citric and lactic) and hydrochloric acid on membrane fatty acid composition and heat resistance of Salmonella typhimurium CECT 443 were studied. The heat resistance was maximal in cells grown at 45 degrees C (cells grown in non-acidified BHI showed a D58-value of 0.90 min) and decreased with decreasing growth temperature up to 10 degrees C (D58-value of 0.09 min). The growth of cells in acidified media caused an increase in their heat resistance. In general, acid adapted cells showed D-values of between 1.5 and 2 times higher than the corresponding for non-acid adapted control cells. This cross-protection response, which has important implications in food processing, was not dependent on the pH value and the acid used to acidify the growth medium. A membrane adaptation corresponding to an increase in the unsaturated to saturated fatty acids ratio (UFA/SFA) and membrane fluidity was observed at low growth temperature. Moreover, the acidification of the growth medium caused a decrease in UFA/SFA ratio and in the C18:1 relative concentration, and an increase in cyclopropane fatty acids (CFA) content mainly due to the increase in cyc19 relative concentration. Thus, acid adapted cells showed CFA levels 1.5 times higher than non-acid adapted control cells. A significant proportion of unsaturated fatty acids were converted to their cyclopropane derivatives during acid adaptation. These changes in membrane fatty acid composition result in cells with decreased membrane fluidity. A clear relation between membrane fatty acid composition and heat resistance was observed. In general, D-values were maximum for cells with low UFA/SFA ratio, and, consequently, with low membrane fluidity. Moreover, CFA formation played a major role in protecting acid adapted cells from heat inactivation. However

  14. FISPACT-II: An Advanced Simulation System for Activation, Transmutation and Material Modelling

    NASA Astrophysics Data System (ADS)

    Sublet, J.-Ch.; Eastwood, J. W.; Morgan, J. G.; Gilbert, M. R.; Fleming, M.; Arter, W.

    2017-01-01

    Fispact-II is a code system and library database for modelling activation-transmutation processes, depletion-burn-up, time dependent inventory and radiation damage source terms caused by nuclear reactions and decays. The Fispact-II code, written in object-style Fortran, follows the evolution of material irradiated by neutrons, alphas, gammas, protons, or deuterons, and provides a wide range of derived radiological output quantities to satisfy most needs for nuclear applications. It can be used with any ENDF-compliant group library data for nuclear reactions, particle-induced and spontaneous fission yields, and radioactive decay (including but not limited to TENDL-2015, ENDF/B-VII.1, JEFF-3.2, JENDL-4.0u, CENDL-3.1 processed into fine-group-structure files, GEFY-5.2 and UKDD-16), as well as resolved and unresolved resonance range probability tables for self-shielding corrections and updated radiological hazard indices. The code has many novel features including: extension of the energy range up to 1 GeV; additional neutron physics including self-shielding effects, temperature dependence, thin and thick target yields; pathway analysis; and sensitivity and uncertainty quantification and propagation using full covariance data. The latest ENDF libraries such as TENDL encompass thousands of target isotopes. Nuclear data libraries for Fispact-II are prepared from these using processing codes PREPRO, NJOY and CALENDF. These data include resonance parameters, cross sections with covariances, probability tables in the resonance ranges, PKA spectra, kerma, dpa, gas and radionuclide production and energy-dependent fission yields, supplemented with all 27 decay types. All such data for the five most important incident particles are provided in evaluated data tables. The Fispact-II simulation software is described in detail in this paper, together with the nuclear data libraries. The Fispact-II system also includes several utility programs for code-use optimisation

  15. Composite Materials

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Langley Research Center researchers invented an advanced polymer, a chemical compound formed by uniting many small molecules to create a complex molecule with different chemical properties. The material is a thermoplastic polyimide that resists solvents. Other polymers of this generic type are soluble in solvents, thus cannot be used where solvents are present. High Technology Services (HTS), Inc. licensed technology and is engaged in development and manufacture of high performance plastics, resins and composite materials. Techimer Materials Division is using technology for composite matrix resins that offer heat resistance and protection from radiation, electrical and chemical degradation. Applications of new polymer include molding resins, adhesives and matrix resins for fiber reinforced composites.

  16. Reduced heat resistance of mutant spores after cloning and mutagenesis of the Bacillus subtilis gene encoding penicillin-binding protein 5.

    PubMed Central

    Todd, J A; Roberts, A N; Johnstone, K; Piggot, P J; Winter, G; Ellar, D J

    1986-01-01

    Part of the gene encoding penicillin-binding protein 5 from Bacillus subtilis 168 was cloned in Escherichia coli with a synthetic oligonucleotide as a hybridization probe. The gene was designated dacA by analogy with E. coli. The nucleotide sequence was determined, and the predicted molecular mass was 45,594 daltons (412 amino acids). A comparison of the predicted amino acid sequence with that of the E. coli penicillin-binding protein 5 indicated that these enzymes showed about 25% identity. The B. subtilis dacA gene was mutated by integration of a plasmid into the structural gene by homologous recombination. A comparison of the mutant and control strains revealed that (i) the mutant lacked detectable penicillin-binding protein 5, (ii) the D-alanine carboxypeptidase activity of membranes isolated from the mutant was only 5% of that measured in membranes from the control strain, (iii) the mutant cells showed apparently normal morphology only during exponential growth, and after the end of exponential phase the cells became progressively shorter, (iv) the mutant sporulated normally except that the forespore occupied about two-thirds of the mother cell cytoplasm and, during its development, migrated towards the center of the mother cell, and (v) purified mutant spores were 10-fold less heat resistant but possessed normal refractility and morphology. Preliminary chemical analysis indicated that the structure of the cortex of the mutant was different. Images PMID:3087956

  17. Heat Resistance of Histidine Decarboxylase from Gram-Negative Histamine-Producing Bacteria in Seafood.

    PubMed

    Bjornsdottir-Butler, K; Bencsath, F A; McCarthy, S; Benner, R A

    2017-08-01

    Precooking of tuna is a potential critical control point (CCP) in the commercial manufacturing of canned tuna. To assess the efficacy of precooking as a CCP, an understanding of the thermal properties of histamine-producing bacteria (HPB) and their histidine decarboxylase (HDC) enzymes is required. The thermal properties of many HPB have been determined, but the thermal resistances of the HDC enzymes are unknown. The purpose of this study was to determine the D- and z-values of selected HDC enzymes to evaluate the CCP of precooking during the canning process and provide scientific data to support U.S. Food and Drug Administration guidelines. HDC (hdc) genes from three strains each of Morganella morganii, Enterobacter aerogenes, Raoultella planticola, and Photobacterium damselae were cloned, expressed, and purified using the Champion pET Directional TOPO Expression System, pET100 cloning vector, and HisPur Cobalt resin. The heat resistances of all enzymes were compared at 50°C, and the D- and z-values from one strain of each HPB were determined at 50 to 60°C. To evaluate the heat inactivation of HDC enzymes during canned tuna processing, tuna tissue was inoculated with HDCs and heated to 60°C in a water bath set at 65 and 100°C. The D-values for the HDC enzymes from M. morganii, E. aerogenes, R. planticola, and P. damselae ranged from 1.6 to 4.1, 1.6 to 6.3, 1.9 to 4.3, and 1.6 to 2.9 min, respectively, at 50 to 60°C. The z-values for M. morganii, E. aerogenes, R. planticola, and P. damselae were 19.2, 18.0, 22.0, and 13.3°C, respectively. The HDCs from all HPB except E. aerogenes showed no significant activity after being heated to 60°C. The data generated in this study will help refine current guidelines for the thermal destruction of the HDC enzymes.

  18. An Overview of 2014 SBIR Phase I and Phase II Materials Structures for Extreme Environments

    NASA Technical Reports Server (NTRS)

    Nguyen, Hung D.; Steele, Gynelle C.; Morris, Jessica R.

    2015-01-01

    NASA's Small Business Innovation Research (SBIR) program focuses on technological innovation by investing in development of innovative concepts and technologies to help NASA mission directorates address critical research needs for Agency programs. This report highlights nine of the innovative SBIR 2014 Phase I and Phase II projects that emphasize one of NASA Glenn Research Center's six core competencies-Materials and Structures for Extreme Environments. The technologies cover a wide spectrum of applications such as high temperature environmental barrier coating systems, deployable space structures, solid oxide fuel cells, and self-lubricating hard coatings for extreme temperatures. Each featured technology describes an innovation, technical objective, and highlights NASA commercial and industrial applications. This report provides an opportunity for NASA engineers, researchers, and program managers to learn how NASA SBIR technologies could help their programs and projects, and lead to collaborations and partnerships between the small SBIR companies and NASA that would benefit both.

  19. Removal of copper(II) from aqueous solution by Jordanian pottery materials.

    PubMed

    Khazali, Omar; Abu-El-Halawa, Rajab; Al-Sou'od, Khaldoun

    2007-01-02

    The aim of this work was to assess the possibility of removing some heavy metals from water by a low-cost adsorbent, like Jordanian raw pottery. Five types of raw and modified pottery materials have been investigated. The effects of initial metal concentration, agitation time, pH and temperature on the removal of Cu(II) were studied. A pseudo-first order was used to test the adsorption kinetics. In order to investigate the sorption isotherm, two equilibrium models, the Freundlich and Langmuir isotherms, were analyzed. The effect of solution pH on the adsorption onto pottery was studied in the pH range 1-5. The adsorption was exothermic at ambient temperature and the computation of the parameters, DeltaH, DeltaS and DeltaG, indicated the interactions to be thermodynamically favorable.

  20. SNMSP II: A system to fully automate special nuclear materials accountability reporting for electric utilities

    SciTech Connect

    Pareto, V.; Venegas, R.

    1987-07-01

    The USNRC requires each licensee who is authorized to possess Special Nuclear Materials (SNM) to prepare and submit reports concerning SNM received, produced, possessed, transferred, consumed, disposed of, or lost. These SNM accountability reports, which need to be submitted twice a year, contain detailed information on the origin, quantity, and type of SNM for several locations. The amount of detail required makes these reports very time consuming and error prone when prepared manually. Yankee Atomic is developing an IBM PC-based computer code that fully automates the process of generating SNM accountability reports. The program, called SNMSP II, prints a number of summaries including facsimiles of the NRC/DOE-741, 742, 742C, and RW-859 reports in a format that can be submitted directly to the NRC/DOE. SNMSP II is menu-driven and is especially designed for people with little or no computer training. Input can be either from a mainframe-based corporate data base or manually through user-friendly screens. In addition, extensive quality assurance features are available to ensure the security and accuracy of the data. This paper discusses the major features of the code and describes its implementation at Yankee.

  1. Atomistic simulation of nanoporous layered double hydroxide materials and their properties. II. Adsorption and diffusion

    NASA Astrophysics Data System (ADS)

    Kim, Nayong; Harale, Aadesh; Tsotsis, Theodore T.; Sahimi, Muhammad

    2007-12-01

    Nanoporous layered double hydroxide (LDH) materials have wide applications, ranging from being good adsorbents for gases (particularly CO2) and liquid ions to membranes and catalysts. They also have applications in medicine, environmental remediation, and electrochemistry. Their general chemical composition is [M1-xIIMxIII(OH-)2]x+[Xn/mm -•nH2O], where M represents a metallic cation (of valence II or III), and Xn/mm - is an m-valence inorganic, or heteropolyacid, or organic anion. We study diffusion and adsorption of CO2 in a particular LDH with MII=Mg, MIII=Al, and x ≃0.71, using an atomistic model developed based on energy minimization and molecular dynamics simulations, together with a modified form of the consistent-valence force field. The adsorption isotherms and self-diffusivity of CO2 in the material are computed over a range of temperature, using molecular simulations. The computed diffusivities are within one order of magnitude of the measured ones at lower temperatures, while agreeing well with the data at high temperatures. The measured and computed adsorption isotherms agree at low loadings, but differ by about 25% at high loadings. Possible reasons for the differences between the computed properties and the experimental data are discussed, and a model for improving the accuracy of the computed properties is suggested. Also studied are the material's hydration and swelling properties. As water molecules are added to the pore space, the LDH material swells to some extent, with the hydration energy exhibiting interesting variations with the number of the water molecules added. The implications of the results are discussed.

  2. Irradiation and compatibility testing of Li/sub 2/O materials at EBR-II

    SciTech Connect

    Porter, D.L.; Krsul, J.R.; Laug, M.T.; Tetenbaum, M.; Walters, L.C.

    1982-12-01

    A study was made of the neutron-irradiation behavior of /sup 6/Li-enriched Li/sub 2/O material in EBR-II. In addition, a stress corrosion study was performed ex-reactor to test compatibility of Li/sub 2/O materials with a variety of stainless steels. Results of the irradiation testing showed that tritium and helium retention in the Li/sub 2/O (approx. 89% dense) lessened with neutron exposure. Helium tritium retention appeared to approach steady-state after approx. 1% /sup 6/Li burnup. The effect was likely caused by the formation of open porosity in the pellets. The stress corrosion studies, using a 316 stainless steel (Ti-modified) and a 35% Ni alloy, showed that stress does not enhance the corrosion, and that dry Li/sub 2/O is not significantly corrosive, the LiOH content producing the corrosive effects. Corrosion, in general, was not severe as a passivation in sealed capsules seemed to occur after a time greatly reducing corrosion rates.

  3. Hydramite II screening tests of potential bremsstrahlung converter debris shield materials

    SciTech Connect

    Reedy, E.D. Jr.; Hedemann, M.A.; Stark, M.A.

    1986-03-01

    Results of a brief test series aimed at screening a number of potential bremsstrahlung converter debris shield materials are reported. These tests were run on Sandia National Laboratories' Hydramite II accelerator using a diode configuration which produces a pinched electron beam. The materials tested include: (1) laminated Kevlar 49/polyester and E-glass/polyester composites, (2) a low density laminated Kevlar 49 composite, and (3) two types of through-the-thickness reinforced Kevlar 49 composites. As expected, tests using laminated Kevlar 49/polyester shields showed that shield permanent set (i.e., permanent deflection) increased with increasing tantalum conversion foil thickness and decreased with increasing shield thickness. The through-the-thickness reinforced composites developed localized, but severe, back surface damage. The laminated composites displayed little back surface damage, although extensive internal matrix cracking and ply delaminations were generated. Roughly the same degree of permanent set was produced in shields made from the low density Kevlar 49 composite and the Kevlar 49/polyester. The E-glass reinforced shields exhibited relatively low levels of permanent set.

  4. Characterization of LWIR diodes on InAs/GaSb Type-II superlattice material

    NASA Astrophysics Data System (ADS)

    Rhiger, David R.; Kvaas, Robert E.; Harris, Sean F.; Hill, Cory J.

    2009-11-01

    Long wavelength infrared (LWIR) focal plane arrays (FPAs) built on Type-II strained layer InAs/GaSb superlattice materials are emerging as an alternative to LWIR HgCdTe. We have made progress in the development of this technology in a collaborative effort between Raytheon Vision Systems and Jet Propulsion Laboratory, resulting in successful devices with LWIR cutoff wavelengths. We report here two investigations related to wafer processing and superlattice material characteristics. The critical interface between the superlattice and the silicon dioxide passivation was examined at the atomic scale by high resolution transmission electron microscopy (HRTEM), showing a conformal coating on an InAs/GaSb mesa sidewall, which undulates with the superlattice periodicity due to differential etching. Electron energy loss spectroscopy (EELS) showed that oxides of the superlattice elements were present but minimal, and some occasional arsenic precipitates were observed at the passivation interface. Our previous analysis of the current-voltage curves was extended further to reveal the minority carrier lifetimes responsible for producing the generation-recombination (GR) and the diffusion dark currents. Lifetimes at 78 K were found to be 6 and 20 ns in the GR and diffusion processes, respectively. Lifetimes from both mechanisms track together with temperature. A HgCdTe diode was analyzed in the same manner for comparison.

  5. The Biodiversity of the Microbiota Producing Heat-Resistant Enzymes Responsible for Spoilage in Processed Bovine Milk and Dairy Products

    PubMed Central

    Machado, Solimar G.; Baglinière, François; Marchand, Sophie; Van Coillie, Els; Vanetti, Maria C. D.; De Block, Jan; Heyndrickx, Marc

    2017-01-01

    Raw bovine milk is highly nutritious as well as pH-neutral, providing the ideal conditions for microbial growth. The microbiota of raw milk is diverse and originates from several sources of contamination including the external udder surface, milking equipment, air, water, feed, grass, feces, and soil. Many bacterial and fungal species can be found in raw milk. The autochthonous microbiota of raw milk immediately after milking generally comprises lactic acid bacteria such as Lactococcus, Lactobacillus, Streptococcus, and Leuconostoc species, which are technologically important for the dairy industry, although they do occasionally cause spoilage of dairy products. Differences in milking practices and storage conditions on each continent, country and region result in variable microbial population structures in raw milk. Raw milk is usually stored at cold temperatures, e.g., about 4°C before processing to reduce the growth of most bacteria. However, psychrotrophic bacteria can proliferate and contribute to spoilage of ultra-high temperature (UHT) treated and sterilized milk and other dairy products with a long shelf life due to their ability to produce extracellular heat resistant enzymes such as peptidases and lipases. Worldwide, species of Pseudomonas, with the ability to produce these spoilage enzymes, are the most common contaminants isolated from cold raw milk although other genera such as Serratia are also reported as important milk spoilers, while for others more research is needed on the heat resistance of the spoilage enzymes produced. The residual activity of extracellular enzymes after high heat treatment may lead to technological problems (off flavors, physico-chemical instability) during the shelf life of milk and dairy products. This review covers the contamination patterns of cold raw milk in several parts of the world, the growth potential of psychrotrophic bacteria, their ability to produce extracellular heat-resistant enzymes and the consequences for

  6. Heat-resistant, extended-spectrum β-lactamase-producing Klebsiella pneumoniae in endoscope-mediated outbreak.

    PubMed

    Jørgensen, S B; Bojer, M S; Boll, E J; Martin, Y; Helmersen, K; Skogstad, M; Struve, C

    2016-05-01

    We describe an outbreak with an extended-spectrum β-lactamase-producing Klebsiella pneumoniae strain in an intensive care unit in a secondary care hospital in Norway. The outbreak source was a fibreoptic intubation endoscope in which the outbreak strain survived despite chemothermal disinfection in a decontaminator designated for such use. The genetic marker clpK, which increases microbial heat resistance, has previously been described in K. pneumoniae outbreak strains. To investigate the role of clpK in biofilm formation and heat-shock stability in the outbreak strain. The outbreak investigation was done by review of clinical records, screening of patients and culture from intubation endoscopes and bronchoscopes. Amplified fragment length polymorphism was used to identify the outbreak strain. clpK detection was performed by polymerase chain reaction, followed by mutant construction and heat-shock assays. Five patients and one intubation endoscope contained K. pneumoniae with the same amplified fragment length polymorphism pattern. The outbreak strain contained the clpK genetic marker, which rendered the strain its increased heat resistance. The survival rate of the strain grown as biofilm following heat treatment was also strongly dependent on clpK. Although clpK has been associated with clinical isolates of K. pneumoniae in earlier outbreaks, this is the first time that a ClpK-producing strain has been isolated from an environmental outbreak source. Heat resistance of certain K. pneumoniae strains may facilitate survival in biofilms on medical equipment and hence increase the potential of those strains to persist and disperse in the hospital environment. Copyright © 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  7. The Biodiversity of the Microbiota Producing Heat-Resistant Enzymes Responsible for Spoilage in Processed Bovine Milk and Dairy Products.

    PubMed

    Machado, Solimar G; Baglinière, François; Marchand, Sophie; Van Coillie, Els; Vanetti, Maria C D; De Block, Jan; Heyndrickx, Marc

    2017-01-01

    Raw bovine milk is highly nutritious as well as pH-neutral, providing the ideal conditions for microbial growth. The microbiota of raw milk is diverse and originates from several sources of contamination including the external udder surface, milking equipment, air, water, feed, grass, feces, and soil. Many bacterial and fungal species can be found in raw milk. The autochthonous microbiota of raw milk immediately after milking generally comprises lactic acid bacteria such as Lactococcus, Lactobacillus, Streptococcus, and Leuconostoc species, which are technologically important for the dairy industry, although they do occasionally cause spoilage of dairy products. Differences in milking practices and storage conditions on each continent, country and region result in variable microbial population structures in raw milk. Raw milk is usually stored at cold temperatures, e.g., about 4°C before processing to reduce the growth of most bacteria. However, psychrotrophic bacteria can proliferate and contribute to spoilage of ultra-high temperature (UHT) treated and sterilized milk and other dairy products with a long shelf life due to their ability to produce extracellular heat resistant enzymes such as peptidases and lipases. Worldwide, species of Pseudomonas, with the ability to produce these spoilage enzymes, are the most common contaminants isolated from cold raw milk although other genera such as Serratia are also reported as important milk spoilers, while for others more research is needed on the heat resistance of the spoilage enzymes produced. The residual activity of extracellular enzymes after high heat treatment may lead to technological problems (off flavors, physico-chemical instability) during the shelf life of milk and dairy products. This review covers the contamination patterns of cold raw milk in several parts of the world, the growth potential of psychrotrophic bacteria, their ability to produce extracellular heat-resistant enzymes and the consequences for

  8. Assessment of heat resistance of bacterial spores from food product isolates by fluorescence monitoring of dipicolinic acid release.

    PubMed

    Kort, Remco; O'Brien, Andrea C; van Stokkum, Ivo H M; Oomes, Suus J C M; Crielaard, Wim; Hellingwerf, Klaas J; Brul, Stanley

    2005-07-01

    This study is aimed at the development and application of a convenient and rapid optical assay to monitor the wet-heat resistance of bacterial endospores occurring in food samples. We tested the feasibility of measuring the release of the abundant spore component dipicolinic acid (DPA) as a probe for heat inactivation. Spores were isolated from the laboratory type strain Bacillus subtilis 168 and from two food product isolates, Bacillus subtilis A163 and Bacillus sporothermodurans IC4. Spores from the lab strain appeared much less heat resistant than those from the two food product isolates. The decimal reduction times (D values) for spores from strains 168, A163, and IC4 recovered on Trypticase soy agar were 1.4, 0.7, and 0.3 min at 105 degrees C, 120 degrees C, and 131 degrees C, respectively. The estimated Z values were 6.3 degrees C, 6.1 degrees C, and 9.7 degrees C, respectively. The extent of DPA release from the three spore crops was monitored as a function of incubation time and temperature. DPA concentrations were determined by measuring the emission at 545 nm of the fluorescent terbium-DPA complex in a microtiter plate fluorometer. We defined spore heat resistance as the critical DPA release temperature (Tc), the temperature at which half the DPA content has been released within a fixed incubation time. We found Tc values for spores from Bacillus strains 168, A163, and IC4 of 108 degrees C, 121 degrees C, and 131 degrees C, respectively. On the basis of these observations, we developed a quantitative model that describes the time and temperature dependence of the experimentally determined extent of DPA release and spore inactivation. The model predicts a DPA release rate profile for each inactivated spore. In addition, it uncovers remarkable differences in the values for the temperature dependence parameters for the rate of spore inactivation, DPA release duration, and DPA release delay.

  9. High-Level Heat Resistance of Spores of Bacillus amyloliquefaciens and Bacillus licheniformis Results from the Presence of a spoVA Operon in a Tn1546 Transposon

    PubMed Central

    Berendsen, Erwin M.; Koning, Rosella A.; Boekhorst, Jos; de Jong, Anne; Kuipers, Oscar P.; Wells-Bennik, Marjon H. J.

    2016-01-01

    Bacterial endospore formers can produce spores that are resistant to many food processing conditions, including heat. Some spores may survive heating processes aimed at production of commercially sterile foods. Recently, it was shown that a spoVA operon, designated spoVA2mob, present on a Tn1546 transposon in Bacillus subtilis, leads to profoundly increased wet heat resistance of B. subtilis spores. Such Tn1546 transposon elements including the spoVA2mob operon were also found in several strains of Bacillus amyloliquefaciens and Bacillus licheniformis, and these strains were shown to produce spores with significantly higher resistances to wet heat than their counterparts lacking this transposon. In this study, the locations and compositions of Tn1546 transposons encompassing the spoVA2mob operons in B. amyloliquefaciens and B. licheniformis were analyzed. Introduction of these spoVA2mob operons into B. subtilis 168 (producing spores that are not highly heat resistant) rendered mutant 168 strains that produced high-level heat resistant spores, demonstrating that these elements in B. amyloliquefaciens and B. licheniformis are responsible for high level heat resistance of spores. Assessment of growth of the nine strains of each species between 5.2°C and 57.7°C showed some differences between strains, especially at lower temperatures, but all strains were able to grow at 57.7°C. Strains of B. amyloliquefaciens and B. licheniformis that contain the Tn1546 elements (and produce high-level heat resistant spores) grew at temperatures similar to those of their Tn1546-negative counterparts that produce low-level heat resistant spores. The findings presented in this study allow for detection of B. amyloliquefaciens and B. licheniformis strains that produce highly heat resistant spores in the food chain. PMID:27994575

  10. High-Level Heat Resistance of Spores of Bacillus amyloliquefaciens and Bacillus licheniformis Results from the Presence of a spoVA Operon in a Tn1546 Transposon.

    PubMed

    Berendsen, Erwin M; Koning, Rosella A; Boekhorst, Jos; de Jong, Anne; Kuipers, Oscar P; Wells-Bennik, Marjon H J

    2016-01-01

    Bacterial endospore formers can produce spores that are resistant to many food processing conditions, including heat. Some spores may survive heating processes aimed at production of commercially sterile foods. Recently, it was shown that a spoVA operon, designated spoVA(2mob), present on a Tn1546 transposon in Bacillus subtilis, leads to profoundly increased wet heat resistance of B. subtilis spores. Such Tn1546 transposon elements including the spoVA(2mob) operon were also found in several strains of Bacillus amyloliquefaciens and Bacillus licheniformis, and these strains were shown to produce spores with significantly higher resistances to wet heat than their counterparts lacking this transposon. In this study, the locations and compositions of Tn1546 transposons encompassing the spoVA(2mob) operons in B. amyloliquefaciens and B. licheniformis were analyzed. Introduction of these spoVA(2mob) operons into B. subtilis 168 (producing spores that are not highly heat resistant) rendered mutant 168 strains that produced high-level heat resistant spores, demonstrating that these elements in B. amyloliquefaciens and B. licheniformis are responsible for high level heat resistance of spores. Assessment of growth of the nine strains of each species between 5.2°C and 57.7°C showed some differences between strains, especially at lower temperatures, but all strains were able to grow at 57.7°C. Strains of B. amyloliquefaciens and B. licheniformis that contain the Tn1546 elements (and produce high-level heat resistant spores) grew at temperatures similar to those of their Tn1546-negative counterparts that produce low-level heat resistant spores. The findings presented in this study allow for detection of B. amyloliquefaciens and B. licheniformis strains that produce highly heat resistant spores in the food chain.

  11. Predicting critical temperatures of iron(II) spin crossover materials: Density functional theory plus U approach

    NASA Astrophysics Data System (ADS)

    Zhang, Yachao

    2014-12-01

    A first-principles study of critical temperatures (Tc) of spin crossover (SCO) materials requires accurate description of the strongly correlated 3d electrons as well as much computational effort. This task is still a challenge for the widely used local density or generalized gradient approximations (LDA/GGA) and hybrid functionals. One remedy, termed density functional theory plus U (DFT+U) approach, introduces a Hubbard U term to deal with the localized electrons at marginal computational cost, while treats the delocalized electrons with LDA/GGA. Here, we employ the DFT+U approach to investigate the Tc of a pair of iron(II) SCO molecular crystals (α and β phase), where identical constituent molecules are packed in different ways. We first calculate the adiabatic high spin-low spin energy splitting ΔEHL and molecular vibrational frequencies in both spin states, then obtain the temperature dependent enthalpy and entropy changes (ΔH and ΔS), and finally extract Tc by exploiting the ΔH/T - T and ΔS - T relationships. The results are in agreement with experiment. Analysis of geometries and electronic structures shows that the local ligand field in the α phase is slightly weakened by the H-bondings involving the ligand atoms and the specific crystal packing style. We find that this effect is largely responsible for the difference in Tc of the two phases. This study shows the applicability of the DFT+U approach for predicting Tc of SCO materials, and provides a clear insight into the subtle influence of the crystal packing effects on SCO behavior.

  12. Towards an accurate and computationally-efficient modelling of Fe(II)-based spin crossover materials.

    PubMed

    Vela, Sergi; Fumanal, Maria; Ribas-Arino, Jordi; Robert, Vincent

    2015-07-07

    The DFT + U methodology is regarded as one of the most-promising strategies to treat the solid state of molecular materials, as it may provide good energetic accuracy at a moderate computational cost. However, a careful parametrization of the U-term is mandatory since the results may be dramatically affected by the selected value. Herein, we benchmarked the Hubbard-like U-term for seven Fe(ii)N6-based pseudo-octahedral spin crossover (SCO) compounds, using as a reference an estimation of the electronic enthalpy difference (ΔHelec) extracted from experimental data (T1/2, ΔS and ΔH). The parametrized U-value obtained for each of those seven compounds ranges from 2.37 eV to 2.97 eV, with an average value of U = 2.65 eV. Interestingly, we have found that this average value can be taken as a good starting point since it leads to an unprecedented mean absolute error (MAE) of only 4.3 kJ mol(-1) in the evaluation of ΔHelec for the studied compounds. Moreover, by comparing our results on the solid state and the gas phase of the materials, we quantify the influence of the intermolecular interactions on the relative stability of the HS and LS states, with an average effect of ca. 5 kJ mol(-1), whose sign cannot be generalized. Overall, the findings reported in this manuscript pave the way for future studies devoted to understand the crystalline phase of SCO compounds, or the adsorption of individual molecules on organic or metallic surfaces, in which the rational incorporation of the U-term within DFT + U yields the required energetic accuracy that is dramatically missing when using bare-DFT functionals.

  13. Examining mechanisms of groundwater Hg(II) treatment by reactive materials: an EXAFS study.

    PubMed

    Gibson, Blair D; Ptacek, Carol J; Lindsay, Matthew B J; Blowes, David W

    2011-12-15

    Laboratory batch experiments were conducted to examine mechanisms of Hg(II) removal by reactive materials proposed for groundwater treatment. These materials included granular iron filings (GIF), 1:1 (w/w) mixtures of metallurgical granular Fe powder + elemental S (MGI+S) and elemental Cu + elemental S (Cu+S), granular activated carbon (GAC), attapulgite clay (ATP), ATP treated with 2-amino-5-thiol-1,3,4-thiadiazole (ATP-a), and ATP treated with 2,5-dimercapto-1,3,4-thiadiazole (ATP-d). Following treatment of simulated groundwater containing 4 mg L(-1) Hg for 8 or 16 days, the solution pH values ranged from 6.8 to 8.8 and Eh values ranged from +400 to -400 mV. Large decreases in aqueous Hg concentrations were observed for ATP-d (>99%), GIF (95%), MGI+S (94%), and Cu+S (90%). Treatment of Hg was less effective using ATP (29%), ATP-a (69%), and GAC (78%). Extended X-ray absorption fine structure (EXAFS) spectra of Hg on GIF, MGI+S, and GAC indicated the presence of an Hg-O bond at 2.04-2.07 Å, suggesting that Hg was bound to GIF corrosion products or to oxygen complexes associated with water sorbed to activated carbon. In contrast, bond lengths ranging from 2.35 to 2.48 Å were observed for Hg in Cu+S, ATP-a, and ATP-d treatments, suggesting the formation of Hg-S bonds.

  14. Predicting critical temperatures of iron(II) spin crossover materials: Density functional theory plus U approach

    SciTech Connect

    Zhang, Yachao

    2014-12-07

    A first-principles study of critical temperatures (T{sub c}) of spin crossover (SCO) materials requires accurate description of the strongly correlated 3d electrons as well as much computational effort. This task is still a challenge for the widely used local density or generalized gradient approximations (LDA/GGA) and hybrid functionals. One remedy, termed density functional theory plus U (DFT+U) approach, introduces a Hubbard U term to deal with the localized electrons at marginal computational cost, while treats the delocalized electrons with LDA/GGA. Here, we employ the DFT+U approach to investigate the T{sub c} of a pair of iron(II) SCO molecular crystals (α and β phase), where identical constituent molecules are packed in different ways. We first calculate the adiabatic high spin-low spin energy splitting ΔE{sub HL} and molecular vibrational frequencies in both spin states, then obtain the temperature dependent enthalpy and entropy changes (ΔH and ΔS), and finally extract T{sub c} by exploiting the ΔH/T − T and ΔS − T relationships. The results are in agreement with experiment. Analysis of geometries and electronic structures shows that the local ligand field in the α phase is slightly weakened by the H-bondings involving the ligand atoms and the specific crystal packing style. We find that this effect is largely responsible for the difference in T{sub c} of the two phases. This study shows the applicability of the DFT+U approach for predicting T{sub c} of SCO materials, and provides a clear insight into the subtle influence of the crystal packing effects on SCO behavior.

  15. Predicting critical temperatures of iron(II) spin crossover materials: density functional theory plus U approach.

    PubMed

    Zhang, Yachao

    2014-12-07

    A first-principles study of critical temperatures (T(c)) of spin crossover (SCO) materials requires accurate description of the strongly correlated 3d electrons as well as much computational effort. This task is still a challenge for the widely used local density or generalized gradient approximations (LDA/GGA) and hybrid functionals. One remedy, termed density functional theory plus U (DFT+U) approach, introduces a Hubbard U term to deal with the localized electrons at marginal computational cost, while treats the delocalized electrons with LDA/GGA. Here, we employ the DFT+U approach to investigate the T(c) of a pair of iron(II) SCO molecular crystals (α and β phase), where identical constituent molecules are packed in different ways. We first calculate the adiabatic high spin-low spin energy splitting ΔE(HL) and molecular vibrational frequencies in both spin states, then obtain the temperature dependent enthalpy and entropy changes (ΔH and ΔS), and finally extract T(c) by exploiting the ΔH/T - T and ΔS - T relationships. The results are in agreement with experiment. Analysis of geometries and electronic structures shows that the local ligand field in the α phase is slightly weakened by the H-bondings involving the ligand atoms and the specific crystal packing style. We find that this effect is largely responsible for the difference in T(c) of the two phases. This study shows the applicability of the DFT+U approach for predicting T(c) of SCO materials, and provides a clear insight into the subtle influence of the crystal packing effects on SCO behavior.

  16. Examining Mechanisms of Groundwater Hg(II) Treatment by Reactive Materials: An EXAFS Study

    SciTech Connect

    Gibson, Blair D.; Ptacek, Carol J.; Lindsay, Matthew B.J.; Blowes, David W.

    2012-02-07

    Laboratory batch experiments were conducted to examine mechanisms of Hg(II) removal by reactive materials proposed for groundwater treatment. These materials included granular iron filings (GIF), 1:1 (w/w) mixtures of metallurgical granular Fe powder + elemental S (MGI+S) and elemental Cu + elemental S (Cu+S), granular activated carbon (GAC), attapulgite clay (ATP), ATP treated with 2-amino-5-thiol-1,3,4-thiadiazole (ATP-a), and ATP treated with 2,5-dimercapto-1,3,4-thiadiazole (ATP-d). Following treatment of simulated groundwater containing 4 mg L{sup -1} Hg for 8 or 16 days, the solution pH values ranged from 6.8 to 8.8 and Eh values ranged from +400 to -400 mV. Large decreases in aqueous Hg concentrations were observed for ATP-d (>99%), GIF (95%), MGI+S (94%), and Cu+S (90%). Treatment of Hg was less effective using ATP (29%), ATP-a (69%), and GAC (78%). Extended X-ray absorption fine structure (EXAFS) spectra of Hg on GIF, MGI+S, and GAC indicated the presence of an Hg-O bond at 2.04-2.07 {angstrom}, suggesting that Hg was bound to GIF corrosion products or to oxygen complexes associated with water sorbed to activated carbon. In contrast, bond lengths ranging from 2.35 to 2.48 {angstrom} were observed for Hg in Cu+S, ATP-a, and ATP-d treatments, suggesting the formation of Hg-S bonds.

  17. Heat resistance of Salmonella enterica is increased by pre-adaptation to peanut oil or sub-lethal heat exposure.

    PubMed

    Fong, Karen; Wang, Siyun

    2016-09-01

    Cross-protection represents a considerable challenge in the food industry where hurdled interventions are often employed to reduce Salmonella contamination. The heat resistance of Salmonella strains from five serotypes (i.e., Typhimurium, Enteritidis, Tennessee, Thompson and Hartford) at 70 °C was determined by measurement of viable cell populations before and after adaptation to two common stresses employed in low-water activity food processing, desiccation and sub-lethal heat treatment. Survival of Salmonella at 70 °C significantly increased (p < 0.05) following the six-day incubation in peanut oil (aw 0.52 ± 0.00) and/or the exposure to a sub-lethal heat treatment at 45 °C for 3 min. Quantitative PCR revealed upregulation of two desiccation stress-related genes, fadA and otsB, following the peanut oil incubation, whereas heat treatment induced upregulation of a heat-resistance gene, dnaK. Invasion gene invA and alternative sigma factor rpoE were downregulated following either of the treatments. Interestingly, different Salmonella strains yielded different transcriptional profiles. The strain-specific resistance phenotypes and transcriptional profiles provided further insights into the mechanisms employed to tolerate desiccation and heat stresses in the food industry.

  18. Dependence of Precipitation Behavior and Creep Strength on Cr Content in High Cr Ferritic Heat Resistant Steels

    NASA Astrophysics Data System (ADS)

    Murata, Yoshinori; Yamashita, Koji; Morinaga, Masahiko; Hara, Toru; Miki, Kazuhiro; Azuma, Tsukasa; Ishiguro, Toru; Hashizume, Ryokichi

    It is known that high temperature tensile strength increases with increasing Cr content in Cr containing heat resistant steels. Recently, however, it was found that long-term creep strength decreased with increasing Cr content in the heat resistant steels containing 8.5-12%Cr. In this study, precipitation behavior of M23C6 carbide and the Z phase after creep tests was investigated using two kinds of high Cr ferritic steels (9Cr and 10.5Cr). As a result, 10.5Cr steel exhibited larger average particle size of M23C6 than 9Cr steel irrespective of creep stress levels, but the amount of M23C6 carbide was almost the same in both steels. On the other hand, the amount of the Z phase became large in 10.5Cr steel compared with 9Cr steel. These experimental results indicate that high level of Cr content accelerates precipitation and coalescence rate of both M23C6 carbide and the Z phase, resulting in degradation of long term creep strength in 10.5 Cr steel compared to 9Cr steel.

  19. Peculiar features of boron distribution in high temperature fracture area of rapidly quenched heat-resistant nickel alloy

    SciTech Connect

    Shulga, A. V.

    2016-12-15

    This article comprises the results of comprehensive study of the structure and distribution in the high temperature fracture area of rapidly quenched heat-resistant superalloy of grade EP741NP after tensile tests. The structure and boron distribution in the fracture area are studied in detail by means of direct track autoradiography in combination with metallography of macro- and microstructure. A rather extensive region of microcracks generation and intensive boron redistribution is detected in the high temperature fracture area of rapidly quenched nickel superalloy of grade EP741NP. A significant decrease in boron content in the fracture area and formation of elliptically arranged boride precipitates are revealed. The mechanism of intense boron migration and stability violation of the structural and phase state in the fracture area of rapidly quenched heat-resistant nickel superalloy of grade EP741NP is proposed on the basis of accounting for deformation occurring in the fracture area and analysis of the stressed state near a crack.

  20. Extreme Heat Resistance of Food Borne Pathogens Campylobacter jejuni, Escherichia coli, and Salmonella typhimurium on Chicken Breast Fillet during Cooking

    PubMed Central

    de Jong, Aarieke E. I.; van Asselt, Esther D.; Zwietering, Marcel H.; Nauta, Maarten J.; de Jonge, Rob

    2012-01-01

    The aim of this research was to determine the decimal reduction times of bacteria present on chicken fillet in boiling water. The experiments were conducted with Campylobacter jejuni, Salmonella, and Escherichia coli. Whole chicken breast fillets were inoculated with the pathogens, stored overnight (4°C), and subsequently cooked. The surface temperature reached 70°C within 30 sec and 85°C within one minute. Extremely high decimal reduction times of 1.90, 1.97, and 2.20 min were obtained for C. jejuni, E. coli, and S. typhimurium, respectively. Chicken meat and refrigerated storage before cooking enlarged the heat resistance of the food borne pathogens. Additionally, a high challenge temperature or fast heating rate contributed to the level of heat resistance. The data were used to assess the probability of illness (campylobacteriosis) due to consumption of chicken fillet as a function of cooking time. The data revealed that cooking time may be far more critical than previously assumed. PMID:22389647

  1. Increased heat resistance in mycelia from wood fungi prevalent in forests characterized by fire: a possible adaptation to forest fire.

    PubMed

    Carlsson, Fredrik; Edman, Mattias; Holm, Svante; Eriksson, Anna-Maria; Jonsson, Bengt Gunnar

    2012-10-01

    Forest fires have been the major stand-replacing/modifying disturbance in boreal forests. To adapt to fire disturbance, different strategies have evolved. This study focuses on wood fungi, and a specific adaptation to forest fire: increased heat resistance in their mycelia. Fifteen species of wood fungi were selected and a priori sorted in two groups according to their prevalence in fire-affected environments. The fungi were cultivated on fresh wood and exposed to 100, 140, 180, 220 °C for 5, 10, 15, 20 and 25 min. under laboratory conditions. A clear difference was found among the two groups. Species prevalent in fire-affected habitats had a much higher survival rate over all combinations of time and temperature compared to species associated with other environments. Thus, the results indicate that fire adaptation in terms of increased heat resistance in mycelia occurs in some species of wood fungi. Such adaptation will influence the ecology and population dynamics of wood fungi, as well as having implications for best practices during restoration fires. Copyright © 2012 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  2. Effect of NaCl on heat resistance, antibiotic susceptibility, and Caco-2 cell invasion of Salmonella.

    PubMed

    Yoon, Hyunjoo; Park, Beom-Young; Oh, Mi-Hwa; Choi, Kyoung-Hee; Yoon, Yohan

    2013-01-01

    This study evaluated the effects of NaCl on heat resistance, antibiotic susceptibility, and Caco-2 cell invasion of Salmonella. Salmonella typhimurium NCCP10812 and Salmonella enteritidis NCCP12243 were exposed to 0, 2, and 4% NaCl and to sequential increase of NaCl concentrations from 0 to 4% NaCl for 24 h at 35°C. The strains were then investigated for heat resistance (60°C), antibiotic susceptibility to eight antibiotics, and Caco-2 cell invasion efficiency. S. typhimurium NCCP10812 showed increased thermal resistance (P < 0.05) after exposure to single NaCl concentrations. A sequential increase of NaCl concentration decreased (P < 0.05) the antibiotic sensitivities of S. typhimurium NCCP10812 to chloramphenicol, gentamicin, and oxytetracycline. NaCl exposure also increased (P < 0.05) Caco-2 cell invasion efficiency of S. enteritidis NCCP12243. These results indicate that NaCl in food may cause increased thermal resistance, cell invasion efficiency, and antibiotic resistance of Salmonella.

  3. Interpretation of high-temperature tensile properties by thermodynamically calculated equilibrium phase diagrams of heat-resistant austenitic cast steels

    NASA Astrophysics Data System (ADS)

    Jung, Seungmun; Sohn, Seok Su; Choi, Won-Mi; Lee, Byeong-Joo; Oh, Yong-Jun; Jang, Seongsik; Lee, Sunghak

    2017-01-01

    High-temperature tensile properties of three heat-resistant austenitic cast steels fabricated by varying W, Mo, and Al contents were interpreted by thermodynamically calculated equilibrium phase diagrams of austenite, ferrite, and carbides as well as microstructural analyses. A two-step calculation method was adopted to cast steel microstructures below the liquid dissolution temperature because the casting route was not an equilibrium state. Thermodynamically calculated fractions of equilibrium phases were well matched with experimentally measured fractions. Ferrites existed at room and high temperatures in both equilibrium phase diagrams and actual microstructures, which has not been reported in previous researches on austenitic cast steels. In the W2Mo1Al1 steel, 38% and 12% of ferrite existed in the equilibrium phase diagram and actual microstructure, respectively, and led to the void initiation and coalescence at ferrites and consequently to the serious deterioration of high-temperature strengths. The present equilibrium phase diagrams, besides detailed microstructural analyses, effectively evaluated the high-temperature performance by estimating high-temperature equilibrium phases, and provided an important idea on whether ferrite were formed or not in the heat-resistant austenitic cast steels.

  4. Heat Resistance in Liquids of Enterococcus spp., Listeria spp., Escherichia coli, Yersinia enterocolitica, Salmonella spp. and Campylobacter spp

    PubMed Central

    Sörqvist, S

    2003-01-01

    The aim of the work was to collect, evaluate, summarize and compare heat resistance data reported for Campylobacter, Enterococcus, Escherichia, Listeria, Salmonella and Yersinia spp. The work was limited to resistance in liquids with pH values 6–8. Results obtained under similar experimental conditions were sought. Thermal destruction lines for the various bacterial groups studied were constructed using log10 D values and treatment temperatures. There was a good linear relationship between log10 D and temperature with Escherichia coli, listerias and salmonellas. For campylobacters, enterococci and yersinias the relationships were weaker but, nevertheless, present. Using the slopes of the lines and their 95% confidence limits, z values and their 95% confidence limits were calculated. z values were compared with z values obtained from reports. The equations for the lines were also used for calculation of predicted means of D values at various treatment temperatures. 95% confidence limits on predicted means of D values and on predicted individual D values were also calculated. Lines and values are shown in figures and tables. Differences in heat resistance noted between and within the bacterial groups studied are discussed. PMID:14650540

  5. Doorways II: Community Counselor Reference Materials. On School-Related Gender-Based Violence Prevention and Response

    ERIC Educational Resources Information Center

    US Agency for International Development, 2009

    2009-01-01

    The Doorways training program was designed by the U.S. Agency for International Development (USAID)-funded Safe Schools Program (Safe Schools) to enable teachers, community members and students to prevent and respond to school-related gender-based violence (SRGBV). This booklet, "Doorways II: Community Counselor Reference Materials on…

  6. Role of minerals in thermal alteration of organic matter--II: a material balance.

    PubMed

    Tannenbaum, E; Huizinga, B J; Kaplan, I R

    1986-09-01

    Pyrolysis experiments were performed on Green River and Monterey Formation kerogens (Types I and II, respectively) with and without calcite, illite, or montmorillonite at 300 degrees C for 2 to 1,000 hours under dry and hydrous conditions. Pyrolysis products were identified and quantified, and a material balance of product and reactants resulted. Significant differences were found in the products generated by pyrolysis of kerogens with and without minerals. Both illite and montmorillonite adsorb a considerable portion (up to 80%) of the generated bitumen. The adsorbed bitumen is almost exclusively composed of polar compounds and asphaltenes that crack to yield low molecular weight compounds and insoluble pyrobitumen during prolonged heating. Montmorillonite shows the most pronounced adsorptive and catalytic effects. With calcite however, the pyrolysis products are similar to those from kerogen heated alone, and bitumen adsorption is negligible. Applying these results to maturation of organic matter in natural environments, we suggest that a given type of organic matter associated with different minerals in source rocks will yield different products. Furthermore, the different adsorption capacities of minerals exert a significant influence on the migration of polar and high molecular weight compounds generated from the breakdown of kerogen. Therefore, the overall accumulated products from carbonate source rocks are mainly heavy oils with some gas, whereas light oils and gases are the main products from source rocks that contain expandable clays with catalytic and adsorptive properties.

  7. Carbonaceous material obtained from exhausted coffee by an aqueous solution combustion process and used for cobalt (II) and cadmium (II) sorption.

    PubMed

    Serrano-Gómez, J; López-González, H; Olguín, M T; Bulbulian, S

    2015-06-01

    New carbonaceous materials were obtained using a fast aqueous solution combustion process from mixtures of exhausted coffee, ammonium nitrate (oxidizer) and urea (fuel) heated at 600, 700, 800 or 900 °C. The resulting powders were effective adsorbents for removing Co(II) and Cd(II) from aqueous solutions. Exhausted coffee was also calcined at different temperatures and compared. The products were characterized, and the obtained carbons had BET specific surface areas of 114.27-390.85 m(2)/g and pore diameters of 4.19 to 2.44 nm when the temperature was increased from 600 to 800 °C. Cobalt and cadmium adsorption by the carbonaceous materials was correlated with the maximum adsorption capacities and specific surface areas of the materials. The method reported here is advantageous because it only required 5 min of reaction to improve the textural properties of carbon obtained from exhausted coffee, which play an important role in the material's cobalt and cadmium adsorption capacities.

  8. I: Hydrodynamic-focusing microreactor II: Mechanically interlocked molecules for functional materials

    NASA Astrophysics Data System (ADS)

    Coti, Karla Karina

    I: Microreactors, a class of microfluidics, offer numerous benefits -- such as small sample requirement, short analysis times and automations -- and have been used to study reactions of chemical and biological reagents. In order to understand the relationship between fast mixing, product regioselectivity, as well as the ability to separate, in time and space, the nanoparticle (NP) formation stages, a microreactor capable of fast and controllable mixing was developed (Chapter 1) based on multi-lamination and hydrodynamic-focusing. By taking advantage of the fast and controllable mixing properties of this novel microreactor one can control the time when chemical reactions commence inside the microchannels. These properties of the microreactor can be exploited to improve the product regioselectivity of a diazo-coupling reaction to attain a product distribution of monoazo to diazo product of ˜1:99, a selectivity unprecedented in both conventional, macroscopic reactors and other microfluidic systems. Additionally, the ability to separate different stages during the NP formation process inside the microreactor, allowed us to study the aggregation of polypyrrole NPs. II: Supramolecular actuators and molecular interlocked molecules, such as catenanes and rotaxanes, have attracted considerable attention because of their sophisticated topology and their application in functional molecular devices. The blending of supramolecular and mechanostereochemistry with mesoporous silica NPs has proven to be a powerful combination, leading to the development of a new class of materials -- mechanized silica nanoparticles ( Chapter 2). These new hybrid materials are designed to release their content in response to an external stimuli and their development is being driven by the need to improve current drug delivery technologies. In an effort to explore how the stimuli-controlled mechanical movement of switchable, bistable [2]rotaxanes -- based on a cyclobis(paraquat-p-phenylene) ring

  9. 1-(3,5-Dinitro-1H-pyrazol-4-yl)-3-nitro-1H-1,2,4-triazol-5-amine (HCPT) and its energetic salts: highly thermally stable energetic materials with high-performance.

    PubMed

    Li, Chuan; Zhang, Man; Chen, Qishan; Li, Yingying; Gao, Huiqi; Fu, Wei; Zhou, Zhiming

    2016-11-28

    A novel energetic heat-resistant explosive, 1-(3,5-dinitro-1H-pyrazol-4-yl)-3-nitro-1H-1,2,4-triazol-5-amine (HCPT), has been synthesized along with its salts. An intensive characterization of the compounds is given, including (1)H and (13)C NMR spectroscopy, IR spectroscopy, and elemental analysis. The crystal structures of neutral HCPT (3), its triaminoguanidinium salt (10), 3,4,5-triamino-1,2,4-triazolium salt (12), and copper(ii) complex (16) were determined by single-crystal X-ray diffraction. The physicochemical properties of the compounds, such as density, thermal stability, and sensitivity towards impact and friction were evaluated; all energetic compounds exhibited excellent thermal stabilities with decomposition temperatures ranging from 215 °C to 340 °C, and high positive heats of formation between 622.8 kJ mol(-1) and 1211.7 kJ mol(-1). The detonation pressures and velocities for the energetic compounds were calculated using EXPLO5 (V6.01) based on experimental densities and calculated heats of formation, and the corresponding values were in the ranges of 26.5 GPa to 37.8 GPa and 8236 m s(-1) to 9167 m s(-1). Based on thermal stability values and energetic parameters, compounds 3 and 7 were superior to those of all of the commonly used heat-resistant explosives, which may find potential application as heat-resistant energetic materials.

  10. Organometallic acetylides of Pt(II), Au(I) and Hg(II) as new generation optical power limiting materials.

    PubMed

    Zhou, Gui-Jiang; Wong, Wai-Yeung

    2011-05-01

    Within the scope of nonlinear optics, optical power limiting (OPL) materials are commonly regarded as an important class of compounds which can protect the delicate optical sensors or human eyes from sudden exposure to damaging intense laser beams. Recent efforts have been devoted to developing organometallic acetylide complexes, dendrimers and polymers as high performance OPL materials of the next generation which can favorably optimize the optical limiting/transparency trade-off issue. These metallated materials offer a new avenue towards a new family of highly transparent homo- and heterometallic optical limiters with good solution processability which outperform those of current state-of-the-art visible-light-absorbing competitors such as fullerenes, metalloporphyrins and metallophthalocyanines. This critical review aims to provide a detailed account on the recent advances of these novel OPL chromophores. Their OPL activity was shown to depend strongly on the electronic characters of the aryleneethynylene ligand and transition metal moieties as well as the conjugation chain length of the compounds. Strategies including copolymerization with other transition metals, change of structural geometry, use of a dendritic platform and variation of the type and content of transition metal ions would strongly govern their photophysical behavior and improve the resulting OPL responses. Special emphasis is placed on the structure-OPL response relationships of these organometallic acetylide materials. The research endeavors for realizing practical OPL devices based on these materials have also been presented. This article concludes with perspectives on the current status of the field, as well as opportunities that lie just beyond its frontier (106 references).

  11. New Methods of Simulation of Mn(II) EPR Spectra: Single Crystals, Polycrystalline and Amorphous (Biological) Materials

    NASA Astrophysics Data System (ADS)

    Misra, Sushil K.

    Biological systems exhibit properties of amorphous materials. The Mn(II) ion in amorphous materials is characterized by distributions of spin-Hamiltonian parameters around mean values. It has a certain advantage over other ions, being one of the most abundant elements on the earth. The extent to which living organisms utilize manganese varies from one organism to the other. There is a fairly high concentration of the Mn(II) ion in green plants, which use it in the O2 evolution reaction of photosynthesis (Sauer, 1980). Structure-reactivity relationships in Mn(II)-O2 complexes are given in a review article by Coleman and Taylor (1980). Manganese is a trace requirement in animal nutrition; highly elevated levels of manganese in the diet can be toxic, probably because of an interference with iron homeostasis (Underwood, 1971). On the other hand, animals raised with a dietary deficiency of manganese exhibit severe abnormalities in connective tissue; these problems have been attributed to the obligatory role of Mn(II) in mucopolysaccharide metabolism (Leach, 1971). Mn(II) has been detected unequivocally in living organisms.

  12. Assessment of Heat Resistance of Bacterial Spores from Food Product Isolates by Fluorescence Monitoring of Dipicolinic Acid Release

    PubMed Central

    Kort, Remco; O'Brien, Andrea C.; van Stokkum, Ivo H. M.; Oomes, Suus J. C. M.; Crielaard, Wim; Hellingwerf, Klaas J.; Brul, Stanley

    2005-01-01

    This study is aimed at the development and application of a convenient and rapid optical assay to monitor the wet-heat resistance of bacterial endospores occurring in food samples. We tested the feasibility of measuring the release of the abundant spore component dipicolinic acid (DPA) as a probe for heat inactivation. Spores were isolated from the laboratory type strain Bacillus subtilis 168 and from two food product isolates, Bacillus subtilis A163 and Bacillus sporothermodurans IC4. Spores from the lab strain appeared much less heat resistant than those from the two food product isolates. The decimal reduction times (D values) for spores from strains 168, A163, and IC4 recovered on Trypticase soy agar were 1.4, 0.7, and 0.3 min at 105°C, 120°C, and 131°C, respectively. The estimated Z values were 6.3°C, 6.1°C, and 9.7°C, respectively. The extent of DPA release from the three spore crops was monitored as a function of incubation time and temperature. DPA concentrations were determined by measuring the emission at 545 nm of the fluorescent terbium-DPA complex in a microtiter plate fluorometer. We defined spore heat resistance as the critical DPA release temperature (Tc), the temperature at which half the DPA content has been released within a fixed incubation time. We found Tc values for spores from Bacillus strains 168, A163, and IC4 of 108°C, 121°C, and 131°C, respectively. On the basis of these observations, we developed a quantitative model that describes the time and temperature dependence of the experimentally determined extent of DPA release and spore inactivation. The model predicts a DPA release rate profile for each inactivated spore. In addition, it uncovers remarkable differences in the values for the temperature dependence parameters for the rate of spore inactivation, DPA release duration, and DPA release delay. PMID:16000762

  13. Relationship between membrane fatty acid composition and heat resistance of acid and cold stressed Salmonella senftenberg CECT 4384.

    PubMed

    Alvarez-Ordóñez, Avelino; Fernández, Ana; López, Mercedes; Bernardo, Ana

    2009-05-01

    This study evaluates the adaptative response to heat (63 degrees C) and the modifications in membrane fatty acid composition of Salmonella senftenberg after its growth in an acidified medium and after its exposure to combinations of acid and cold stresses. Cells were grown in Brain Heart Infusion (BHI) buffered at pH 7.0 and acidified up to pH 4.5 (fresh cultures) and kept at refrigeration temperature (4 degrees C) for 7 days (refrigerated cultures). The results indicate that previous adaptation to a low pH increased the bacterial heat resistance, but combinations of sublethal stresses reduced S. senftenberg heat tolerance, specially when the growth medium pH was decreased. Acid-adapted cells showed D(63)-values ranging from 3.10 to 6.27 min, while non-acid-adapted cells showed D(63)-values of 1.07 min. As pH decreased, over the pH range studied (7.4-4.5), D(63)-values of the resulting cells increased. However, refrigerated acid-adapted cells showed lower D(63)-values, which ranged from 0.95 to 0.49 min. A linear relationship between the thermotolerance of S. senftenberg cells and the previous growth medium pH was found in both fresh and refrigerated cultures, which allowed us to predict changes in heat resistance of S. senftenberg that occur at any pH value within the range used in the present study in which most foodstuffs are included. Both acidification of the growth medium and refrigeration storage of cells induced modifications in membrane fatty acid composition, which were clearly linked to their heat resistance. Acid-adapted cells, regardless of the pH value of the growth medium, showed the lowest UFA/SFA ratio and a CFA content 1.5-2-fold higher than that observed for non-acid-adapted cells. On the other hand, the UFA/SFA ratio found for S. senftenberg cells exposed to a cold stress was 1.2-1.8-fold higher than that observed for non-refrigerated cultures. This increase in the UFA/SFA ratio was specially high for acid-adapted cells. The highest

  14. PIREX II — A new irradiation facility for testing fusion first wall materials

    NASA Astrophysics Data System (ADS)

    Marmy, P.; Daum, M.; Gavillet, D.; Green, S.; Green, W. V.; Hegedus, F.; Proennecke, S.; Rohrer, U.; Stiefel, U.; Victoria, M.

    1990-03-01

    A new irradiation facility, PIREX II (Proton Irradiation Experiment), became operational in March 1987. It is located on a dedicated beam line split from the main beam of the 590 MeV proton accelerator at the Paul Scherrer Institute (PSI). Irradiation with protons of this energy introduces simultaneously displacement damage, helium and other impurities. Because of the penetration range of 590 MeV protons, both damage and impurities are homogeneously distributed in the target material. The installation has its own beam line optics that can support a proton current of up to 50 μA. At a typical beam density of 4 {μA}/{mm 2}, the damage rate in steel is 0.7 × 10 -5{dpa}/{s} (dpa: displacements per atom), and the helium production rat He/dpa. Both flat tensile specimens of up to 0.4 mm thickness and tubular fatigue samples of 3 mm diameter can be irradiated. Cooling of the sample is performed by flowing pressurized helium gas over the sample. Irradiation temperatures can be controlled between 100 ° C and 800 ° C. Installation of an in situ low cycle fatigue device is foreseen. Beams of up to 20 μA have been obtained, the beam having an approximately Gaussian distribution of elliptical cross section with 4σ xbetween 0.8 and 8 nun by 4σ y of up to 10 mm. Irradiations for a dosimetry program have been completed on samples of Al, Cu, Fe, Ni, Au, W, and 1.4914 ferritic steel. The evaluation of results allows the correct choice of reactions to be used for determining total dose, from the standpoint of half life and gamma energy. A program of irradiations on candidate materials for the Next European Torus (NET) design (Cu and Cu alloys, 1.4914 ferritic martensitic steel, W and W-Re alloys and Mo and Mo alloys), where the above mentioned characteristics of this type of irradiation can be used advantageously, is now under way.

  15. Adsorbent materials from paper industry waste materials and their use in Cu(II) removal from water.

    PubMed

    Méndez, A; Barriga, S; Fidalgo, J M; Gascó, G

    2009-06-15

    This paper deals with the removal of Cu(2+) from water using adsorbent materials prepared from paper industry waste materials (one de-inking paper sludge and other sludge from virgin pulp mill). Experimental results showed that de-inking paper sludge leads to mesoporous materials (V(mic)/V(T)=0.13 and 0.14), whereas the sludge from virgin pulp mill produces high microporous adsorbents (V(mic)/V(T)=0.39 and 0.41). Adsorbent materials were then used for Cu(2+) removal from water at acid pH. During water treatment, heavy metals lixiviation from adsorbent materials was not produced. However, important Ca and Mg leaching was observed. Final pH significantly increases after treatment of water with adsorbent materials probably due to their elevated CaCO(3) content. In general, highest Cu(2+) removal was obtained using adsorbent materials from de-inking paper sludge. This result could be due to their higher content in oxygenated surface groups, high average pore diameter, elevated superficial charge density, high CaCO(3) amount and high Ca and Mg exchange content.

  16. Sol-gel encapsulation of binary Zn(II) compounds in silica nanoparticles. Structure-activity correlations in hybrid materials targeting Zn(II) antibacterial use.

    PubMed

    Halevas, E; Nday, C M; Kaprara, E; Psycharis, V; Raptopoulou, C P; Jackson, G E; Litsardakis, G; Salifoglou, A

    2015-10-01

    In the emerging issue of enhanced multi-resistant properties in infectious pathogens, new nanomaterials with optimally efficient antibacterial activity and lower toxicity than other species attract considerable research interest. In an effort to develop such efficient antibacterials, we a) synthesized acid-catalyzed silica-gel matrices, b) evaluated the suitability of these matrices as potential carrier materials for controlled release of ZnSO4 and a new Zn(II) binary complex with a suitably designed well-defined Schiff base, and c) investigated structural and textural properties of the nanomaterials. Physicochemical characterization of the (empty-loaded) silica-nanoparticles led to an optimized material configuration linked to the delivery of the encapsulated antibacterial zinc load. Entrapment and drug release studies showed the competence of hybrid nanoparticles with respect to the a) zinc loading capacity, b) congruence with zinc physicochemical attributes, and c) release profile of their zinc load. The material antimicrobial properties were demonstrated against Gram-positive (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus) and negative (Escherichia coli, Pseudomonas aeruginosa, Xanthomonas campestris) bacteria using modified agar diffusion methods. ZnSO4 showed less extensive antimicrobial behavior compared to Zn(II)-Schiff, implying that the Zn(II)-bound ligand enhances zinc antimicrobial properties. All zinc-loaded nanoparticles were less antimicrobially active than zinc compounds alone, as encapsulation controls their release, thereby attenuating their antimicrobial activity. To this end, as the amount of loaded zinc increases, the antimicrobial behavior of the nano-agent improves. Collectively, for the first time, sol-gel zinc-loaded silica-nanoparticles were shown to exhibit well-defined antimicrobial activity, justifying due attention to further development of antibacterial nanotechnology.

  17. Pb(II) adsorption by a novel activated carbon - alginate composite material. A kinetic and equilibrium study.

    PubMed

    Cataldo, Salvatore; Gianguzza, Antonio; Milea, Demetrio; Muratore, Nicola; Pettignano, Alberto

    2016-11-01

    The adsorption capacity of an activated carbon - calcium alginate composite material (ACAA-Ca) has been tested with the aim of developing a new and more efficient adsorbent material to remove Pb(II) ion from aqueous solution. The study was carried out at pH=5, in NaCl medium and in the ionic strength range 0.1-0.75molL(-1). Differential Pulse Anodic Stripping Voltammetry (DP-ASV) technique was used to check the amount of Pb(II) ion removed during kinetic and equilibrium experiments. Different kinetic (pseudo first order, pseudo second order and Vermuelen) and equilibrium (Langmuir and Freundlich) models were used to fit experimental data, and were statistically compared. Calcium alginate (AA-Ca) improves the adsorption capacity (qm) of active carbon (AC) in the ACAA-Ca adsorbent material (e.g., qm=15.7 and 10.5mgg(-1) at I=0.25molL(-1), for ACAA-Ca and AC, respectively). SEM-EDX and thermogravimetric (TGA) measurements were carried out in order to characterize the composite material. The results of the speciation study on the Pb(II) solution and of the characterization of the ACAA-Ca and of the pristine AA-Ca and AC were evaluated in order to explain the specific contribution of AC and AA-Ca to the adsorption of the metal ion. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Possibility of enhancement of the high-temperature strength and the heat resistance of a nickel aluminide-based structural intermetallic alloy

    NASA Astrophysics Data System (ADS)

    Bazyleva, O. A.; Shestakov, A. V.; Arginbaeva, E. G.; Turenko, E. Yu.

    2016-01-01

    The assimilation of a number of rare-earth metals (REM = praseodymium, neodymium, erbium) in a cast high-temperature nickel aluminide-based intermetallic alloy and the effect of REM alloying of the alloy on the critical temperatures, the high-temperature strength, and the heat resistance (time to failure) of the structural alloy are studied. It is shown that the heat resistance and the time to failure of the alloy at 1200°C can be increased by microalloying of the intermetallic alloy with REM.

  19. Short communication: Heat-resistant Escherichia coli as potential persistent reservoir of extended-spectrum β-lactamases and Shiga toxin-encoding phages in dairy.

    PubMed

    Marti, Roger; Muniesa, Maite; Schmid, Michael; Ahrens, Christian H; Naskova, Javorka; Hummerjohann, Jörg

    2016-11-01

    Here we report the isolation of heat-resistant Escherichia coli from raw milk cheeses. Detection of the heat-resistance markers clpK and orfI by PCR was followed by phenotypical confirmation of increased heat-resistance. These strains were Shiga toxin-negative and, although several were found to be multidrug resistant, no plasmids encoding extended-spectrum β-lactamases (ESBL) were found in any of the isolates. The aim of this study was to assess the potential of these strains to acquire ESBL plasmids and a modified Shiga toxin-encoding phage. Only 4 ESBL-encoding, heat-sensitive E. coli strains were isolated from 1,251 dairy samples (2/455 raw milk and 2/796 raw milk cheese samples). One incompatibility group FII plasmid (CTX-M-14, 79.0 kb) and 3 incompatibility group I1 plasmids (CTX-M-15, 95.2, 96.1, and 97.8 kb) were fully sequenced and de novo assembled. All 4 plasmids are readily transferred to heat-resistant E. coli isolates in plate matings (9.7×10(-5) to 3.7×10(-1) exconjugants per recipient) and, to a lesser extent, in milk (up to 7.4×10(-5) exconjugants per recipient). Importantly, the plasmids are stably maintained during passaging in liquid media without antimicrobial pressure. The heat-resistant isolate FAM21805 was also shown to be capable of acting as donor of all 4 ESBL plasmids. In addition, 3 of 11 tested ESBL exconjugants of heat-resistant strains were lysogenized by the modified Shiga toxin-encoding phage 933W ∆stx::gfp::cat. The higher fraction of heat-resistant E. coli (93 of 256 isolates) compared with the estimated 2% previously predicted based on genomic prevalence of heat resistance genes seems to indicate a selection advantage in the raw milk cheese production environment. The combination of 2 factors may lead to said advantage: increased survival during thermization of raw milk (heating to subpasteurization temperatures) and increased survival rates during cheese ripening. Should these strains acquire ESBL-encoding plasmids, Shiga

  20. Microstructural Evolution and Mechanical Properties of Short-Term Thermally Exposed 9/12Cr Heat-Resistant Steels

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Yan, Wei; Sha, Wei; Shan, Yiyin; Yang, Ke

    2012-11-01

    The microstructural evolution during short-term (up to 3000 hours) thermal exposure of three 9/12Cr heat-resistant steels was studied, as well as the mechanical properties after exposure. The tempered martensitic lath structure, as well as the precipitation of carbide and MX type carbonitrides in the steel matrix, was stable after 3000 hours of exposure at 873 K (600 °C). A microstructure observation showed that during the short-term thermal exposure process, the change of mechanical properties was caused mainly by the formation and growth of Laves-phase precipitates in the steels. On thermal exposure, with an increase of cobalt and tungsten contents, cobalt could promote the segregation of tungsten along the martensite lath to form Laves phase, and a large size and high density of Laves-phase precipitates along the grain boundaries could lead to the brittle intergranular fracture of the steels.

  1. Effect of thymol in heating and recovery media on the isothermal and non-isothermal heat resistance of Bacillus spores.

    PubMed

    Esteban, Maria-Dolores; Conesa, Raquel; Huertas, Juan-Pablo; Palop, Alfredo

    2015-06-01

    Members of the genus Bacillus include important food-borne pathogen and spoilage microorganisms for food industry. Essential oils are natural products extracted from herbs and spices, which can be used as natural preservatives in many foods because of their antibacterial, antifungal, antioxidant and anti-carcinogenic properties. The aim of this research was to explore the effect of the addition of different concentrations of thymol to the heating and recovery media on the thermal resistance of spores of Bacillus cereus, Bacillus licheniformis and Bacillus subtilis at different temperatures. While the heat resistance was hardly reduced when thymol was present in the heating medium, the effect in the recovery medium was greater, reducing the D100 °C values down to one third for B. subtilis and B. cereus when 0.5 mM thymol was added. This effect was dose dependent and was also observed at other heating temperatures.

  2. Heat Shock Proteins in Two Lines of Zea mays L. That Differ in Drought and Heat Resistance 1

    PubMed Central

    Ristic, Zoran; Gifford, David J.; Cass, David D.

    1991-01-01

    Synthesis of heat shock proteins (HSPs) in the leaves of a drought- and heat-resistant (line ZPBL 1304), and a drought- and heat-sensitive (line ZPL 389) line of maize (Zea mays L.) was studied under two environmental stress treatments: (a) soil drying and high temperature and (b) high temperature. In the first treatment 13-day-old plants were exposed to 7-day soil drying followed by high temperature stress (45°C), and in the second treatment 20-day-old plants were exposed to high temperature stress (45°C). Second leaves were labeled with [35S]methionine. During the labeling period line ZPBL 1304 showed no signs of leaf dehydration under soil drying and high temperature stress conditions. In contrast, line ZPL 389 was dehydrated 23%, as determined by relative water content. Incorporation of [35S]methionine into protein was greater in the resistant than in the sensitive line in both treatments. The pattern of synthesis of HSPs in the two lines was similar in treatments 1 and 2. Both lines synthesized a high molecular mass set and a low molecular mass set of HSPs. Proteins from both sets from both lines of maize appeared similar to each other, with respect to the molecular mass. Heated plants of the drought- and heat-resistant line ZPBL 1304 synthesized a band of HSP(s) of approximately 45 kilodaltons which was not found in heated plants of the drought and heat sensitive line ZPL 389. This is the first report on qualitative intraspecific difference in the synthesis of HSPs in maize. ImagesFigure 2Figure 3 PMID:16668567

  3. Effect of Water Activities of Heating and Recovery Media on Apparent Heat Resistance of Bacillus cereus Spores

    PubMed Central

    Coroller, Louis; Leguérinel, Ivan; Mafart, Pierre

    2001-01-01

    Spores of Bacillus cereus were heated and recovered in order to investigate the effect of water activity of media on the estimated heat resistance (i.e., the D value) of spores. The water activity (ranging from 0.9 to 1) of the heating medium was first successively controlled with three solutes (glycerol, glucose, and sucrose), while the water activity of the recovery medium was kept near 1. Reciprocally, the water activity of the heating medium was then kept at 1, while the water activity of the recovery medium was controlled from 0.9 to 1 with the same depressors. Lastly, in a third set of experiments, the heating medium and the recovery medium were adjusted to the same activity. As expected, added depressors caused an increase of the heat resistance of spores with a greater efficiency of sucrose with respect to glycerol and glucose. In contrast, when solutes were added to the recovery medium, under an optimal water activity close to 0.98, a decrease of water activity caused a decrease in the estimated D values. This effect was more pronounced when sucrose was used as a depressor instead of glycerol or glucose. When the heating and the recovery media were adjusted to the same water activity, a balancing effect was observed between the protective influence of the solutes during heat treatment and their negative effect during the recovery of injured cells, so that the overall effect of water activity was reduced, with an optimal value near 0.96. The difference between the efficiency of depressors was also less pronounced. It may then be concluded that the overall protective effect of a decrease in water activity is generally overestimated. PMID:11133461

  4. Determination of emissivity coefficient of heat-resistant super alloys and cemented carbide

    NASA Astrophysics Data System (ADS)

    Kieruj, Piotr; Przestacki, Damian; Chwalczuk, Tadeusz

    2016-12-01

    This paper presents the analysis of emissivity engineering materials according to temperature. Experiment is concerned on difficult to machine materials, which may be turned with laser assisting. Cylindrical samples made of nickel-based alloys Inconel 625, Inconel 718, Waspaloy and tungsten-carbides based on cobalt matrix were analyzed. The samples' temperature in contact method was compared to the temperature measured by non-contact pyrometers. Based on this relative, the value of the emissivity coefficient was adjusted to the right indication of pyrometers.

  5. Using coal fly ash as a support for Mn(II), Co(II) and Ni(II) and utilizing the materials as novel oxidation catalysts for 4-chlorophenol mineralization.

    PubMed

    Deka, Bharati; Bhattacharyya, K G

    2015-03-01

    In this work, Mn(II), Co(II) and Ni(II) were incorporated into waste coal fly ash used as a catalyst support by refluxing with the appropriate aqueous salt solution. The materials were calcined at 773-873 K for 5 h and the amount of divalent cations entering into the fly ash was determined by AAS measurements. Further characterization included estimation of oxides by XRF, structural properties by XRD, topographical features by SEM, surface functional groups by FT-IR, surface area and pore dimensions by BET N2-adsorption isotherms. The efficiency of the materials as environmental oxidation catalysts were tested with respect to destruction of 4-chlorophenol (4-CP) in water in the presence of hydrogen peroxide. Considered as one of the most persistent, toxic and largely applied organic compound, 4-CP enters water from the effluents of petrochemical, plastic, pesticide, kraft mill and other organochemical industries and research centers. Wet oxidation of 4-CP was tested by varying the mole ratio of 4-CP and H2O2, catalyst load, temperature, reaction time, 4-CP concentration and pH. Oxidation of 4-CP (5 × 10(-3) M or 643 mg L(-1)) was 51.1% for Mn(II)-fly ash, 58.3% for Co(II)-fly ash and 61.0% for Ni(II)-fly ash after 180 min at 323 K with 4-CP: H2O2 mole ratio of 1:1. COD load of the reaction mixture (4-CP: 5 × 10(-3) M, H2O2: 5 × 10(-3) M, catalyst load: 1.0 g L(-1), temperature 323 K, reaction time 0-240 min) decreased from 1480 to 620, 380, and 140 mg L(-1) respectively after oxidation with Mn(II)-fly ash, Co(II)-fly ash and Ni(II)-fly ash (overall COD reduction was 58.0, 74.3 and 90.5% respectively). The oxidation followed second order kinetics with the average rate coefficient of 7.9, 1.3 and 1.2 L mol(-1) min(-1) for Mn(II)-, Co(II)- and Ni(II)-fly ash. Increase in H2O2: 4-CP mole ratio from 1:1 to 20:1 (reaction time 300 min, catalyst load 1.0 g L(-1)) enhanced destruction from 52.1 to 95.6% for Mn(II)-fly ash, 58.3-95.6% for Co(II)-fly ash and from 60.4 to

  6. Design and characterization of a composite material based on Sr(II)-loaded clay nanotubes included within a biopolymer matrix.

    PubMed

    Del Buffa, Stefano; Bonini, Massimo; Ridi, Francesca; Severi, Mirko; Losi, Paola; Volpi, Silvia; Al Kayal, Tamer; Soldani, Giorgio; Baglioni, Piero

    2015-06-15

    This paper reports on the preparation, characterization, and cytotoxicity of a hybrid nanocomposite material made of Sr(II)-loaded Halloysite nanotubes included within a biopolymer (3-polyhydroxybutyrate-co-3-hydroxyvalerate) matrix. The Sr(II)-loaded inorganic scaffold is intended to provide mechanical resistance, multi-scale porosity, and to favor the in-situ regeneration of bone tissue thanks to its biocompatibility and bioactivity. The interaction of the hybrid system with the physiological environment is mediated by the biopolymer coating, which acts as a binder, as well as a diffusional barrier to the Sr(II) release. The degradation of the polymer progressively leads to the exposure of the Sr(II)-loaded Halloysite scaffold, tuning its interaction with osteogenic cells. The in vitro biocompatibility of the composite was demonstrated by cytotoxicity tests on L929 fibroblast cells. The results indicate that this composite material could be of interest for multiple strategies in the field of bone tissue engineering. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Lightweight inflatable material with low permeability

    NASA Technical Reports Server (NTRS)

    White, E. C.; Matthews, F. R.

    1973-01-01

    Material features combination of Mylar, for strength, and Saran, for impermeable qualities. Second lamination of Mylar prevents blocking, adds strength, and increases barrier rating. Different combinations of laminations produce variety of thicknesses and barrier ratings. Material can be metallized for increased barrier reliability and radar reflectivity, and can be treated with a heat-resistant coating.

  8. Evaluation of H2 Getter Materials for Use in the TRUPACT-II

    SciTech Connect

    Livingston, R.R.

    1999-11-15

    Savannah River Site (SRS) has many waste drums containing Pu-238 that exceed the currently allowed wattage for transportation in the Transuranic Package Transporter-II (TRUPACT-II). By eliminating layers of confinement in waste drums and using getters to remove hydrogen gas, the TRUPACT-II waste loading can be increased significantly, with the potential of reaching the package''s 40-watt thermal limit. The cost savings associated with increasing the waste loading are enormous, and can be measured by reduced numbers of shipments, required processing facilities, and years of effort. To support the decision-making process and provide a good starting point for future development efforts at SRTC, the design requirements for a getter system to be used in the TRUPACT-II were compiled and are discussed in detail in the Appendix.

  9. Adsorption of Azo-Dye Orange II from Aqueous Solutions Using a Metal-Organic Framework Material: Iron- Benzenetricarboxylate

    PubMed Central

    Rojas García, Elizabeth; López Medina, Ricardo; May Lozano, Marcos; Hernández Pérez, Isaías; Valero, Maria J.; Maubert Franco, Ana M.

    2014-01-01

    A Metal-Organic Framework (MOF), iron-benzenetricarboxylate (Fe(BTC)), has been studied for the adsorptive removal of azo-dye Orange II from aqueous solutions, where the effect of various parameters was tested and isotherm and kinetic models were suggested. The adsorption capacities of Fe(BTC) were much higher than those of an activated carbon. The experimental data can be best described by the Langmuir isotherm model (R2 > 0.997) and revealed the ability of Fe(BTC) to adsorb 435 mg of Orange II per gram of adsorbent at the optimal conditions. The kinetics of Orange II adsorption followed a pseudo-second-order kinetic model, indicating the coexistence of physisorption and chemisorption, with intra-particle diffusion being the rate controlling step. The thermodynamic study revealed that the adsorption of Orange II was feasible, spontaneous and exothermic process (−25.53 kJ·mol−1). The high recovery of the dye showed that Fe(BTC) can be employed as an effective and reusable adsorbent for the removal of Orange II from aqueous solutions and showed the economic interest of this adsorbent material for environmental purposes. PMID:28788289

  10. A core-shell structured nanocomposite material for detection, adsorption and removal of Hg(II) ions in water.

    PubMed

    Li, Le; Tang, Shuangyang; Ding, Dexin; Hu, Nan; Yang, Shengyuan; He, Shuya; Wang, Yongdong; Tan, Yan; Sun, Jing

    2012-11-01

    In this paper, a core-shell structured nanocomposite material was prepared for the detection, adsorption and removal of Hg(ll) ions in aqueous solution. The core was made from Fe3O4 nanoparticles with superparamagnetic behavior and the outer shell was made from amorphous silica modified with pyrene-based sensing-probes. The material could detect and adsorb Hg(II) ions in aqueous solution due to its surface being modified with pyrene-based sensing-probes, and could easily be removed from the solution by magnetic force because of its core being made from magnetic Fe3O4 nanoparticles. This multifunctional core-shell structure was confirmed and characterized by TEM, IR spectra, TGA, XRD and N2 adsorption/desorption isotherms. Experiments were conducted on its functions of detection, adsorption and removal of Hg(II) ions in aqueous solution. The experimental results showed that this composite material had high sensitivity and unique selectivity to Hg(II), and that it could easily be removed from the solution.

  11. Inactivation of chemical and heat-resistant spores of Bacillus and Geobacillus by nitrogen cold atmospheric plasma evokes distinct changes in morphology and integrity of spores.

    PubMed

    van Bokhorst-van de Veen, Hermien; Xie, Houyu; Esveld, Erik; Abee, Tjakko; Mastwijk, Hennie; Nierop Groot, Masja

    2015-02-01

    Bacterial spores are resistant to severe conditions and form a challenge to eradicate from food or food packaging material. Cold atmospheric plasma (CAP) treatment is receiving more attention as potential sterilization method at relatively mild conditions but the exact mechanism of inactivation is still not fully understood. In this study, the biocidal effect by nitrogen CAP was determined for chemical (hypochlorite and hydrogen peroxide), physical (UV) and heat-resistant spores. The three different sporeformers used are Bacillus cereus a food-borne pathogen, and Bacillus atrophaeus and Geobacillus stearothermophilus that are used as biological indicators for validation of chemical sterilization and thermal processes, respectively. The different spores showed variation in their degree of inactivation by applied heat, hypochlorite, hydrogen peroxide, and UV treatments, whereas similar inactivation results were obtained with the different spores treated with nitrogen CAP. G. stearothermophilus spores displayed high resistance to heat, hypochlorite, hydrogen peroxide, while for UV treatment B. atrophaeus spores are most tolerant. Scanning electron microscopy analysis revealed distinct morphological changes for nitrogen CAP-treated B. cereus spores including etching effects and the appearance of rough spore surfaces, whereas morphology of spores treated with heat or disinfectants showed no such changes. Moreover, microscopy analysis revealed CAP-exposed B. cereus spores to turn phase grey conceivably because of water influx indicating damage of the spores, a phenomenon that was not observed for non-treated spores. In addition, data are supplied that exclude UV radiation as determinant of antimicrobial activity of nitrogen CAP. Overall, this study shows that nitrogen CAP treatment has a biocidal effect on selected Bacillus and Geobacillus spores associated with alterations in spore surface morphology and loss of spore integrity. Copyright © 2014 Elsevier Ltd. All

  12. A Characterization Study of Several Heat Resistant Explosives in Mild Detonating Cords

    DTIC Science & Technology

    1976-08-30

    formation of 2,i*,6-tripicryltriazine (TPT) was determined by combustion calorimetry , using a platinum-lined rotating- bomb calorimeter. A mixture...were conducted on TPT with several solvents in a Parr stationary adiabatic- bomb calorimeter to determine the heat auxiliary material to use with...TPT. Also, the proper weight ratios to approximate the heat released for initial temperature settings on the rotating bomb , and to test for

  13. Ultrastrong Polyoxyzole Nanofiber Membranes for Dendrite-Proof and Heat-Resistant Battery Separators.

    PubMed

    Hao, Xiaoming; Zhu, Jian; Jiang, Xiong; Wu, Haitao; Qiao, Jinshuo; Sun, Wang; Wang, Zhenhua; Sun, Kening

    2016-05-11

    Polymeric nanomaterials emerge as key building blocks for engineering materials in a variety of applications. In particular, the high modulus polymeric nanofibers are suitable to prepare flexible yet strong membrane separators to prevent the growth and penetration of lithium dendrites for safe and reliable high energy lithium metal-based batteries. High ionic conductance, scalability, and low cost are other required attributes of the separator important for practical implementations. Available materials so far are difficult to comply with such stringent criteria. Here, we demonstrate a high-yield exfoliation of ultrastrong poly(p-phenylene benzobisoxazole) nanofibers from the Zylon microfibers. A highly scalable blade casting process is used to assemble these nanofibers into nanoporous membranes. These membranes possess ultimate strengths of 525 MPa, Young's moduli of 20 GPa, thermal stability up to 600 °C, and impressively low ionic resistance, enabling their use as dendrite-suppressing membrane separators in electrochemical cells. With such high-performance separators, reliable lithium-metal based batteries operated at 150 °C are also demonstrated. Those polyoxyzole nanofibers would enrich the existing library of strong nanomaterials and serve as a promising material for large-scale and cost-effective safe energy storage.

  14. Development and Exchange of Instructional Resources in Water Quality Control Programs, II: Instructional Materials Available.

    ERIC Educational Resources Information Center

    Austin, John H.

    This document is one in a series of reports which reviews instructional materials and equipment for water and wastewater treatment plant personnel. Approximately 900 items are listed in this document along with guidelines for the production of instructional materials. Information is provided regarding the source, type of material, intended…

  15. Development and Exchange of Instructional Resources in Water Quality Control Programs, II: Instructional Materials Available.

    ERIC Educational Resources Information Center

    Austin, John H.

    This document is one in a series of reports which reviews instructional materials and equipment for water and wastewater treatment plant personnel. Approximately 900 items are listed in this document along with guidelines for the production of instructional materials. Information is provided regarding the source, type of material, intended…

  16. Predictive model for the reduction of heat resistance of Listeria monocytogenes in ground beef by the combined effect of sodium chloride and apple polyphenols

    USDA-ARS?s Scientific Manuscript database

    We investigated the combined effect of three internal temperatures (57.5, 60, and 62.5C) and different concentrations (0 to 3.0 wt/wt %) of sodium chloride (NaCl) and apple polyphenols (APP), individually and in combination, on the heat-resistance of a five-strain cocktail of Listeria monocytogenes ...

  17. A low dose pre-irradiation induces radio- and heat-resistance via HDM2 and NO radicals, and is associated with p53 functioning

    NASA Astrophysics Data System (ADS)

    Takahashi, A.; Ohnishi, T.

    2009-04-01

    The aim of this work was to clarify the effect of low dose pre-irradiation on radio- and heat-sensitivity. Wild-type (wt) p53 and mutated (m) p53 cells derived from the human lung cancer H1299 cell line were used. The parental H1299 cell line is p53-null. Cellular sensitivities were determined with a colony-forming assay. When wtp53 cells were exposed to a low dose X-irradiation, induction of radio- and heat-resistance was observed only in the absence of RITA (an inhibitor of p53-HDM2 interactions), aminoguanidine (an iNOS inhibitor) and c-PTIO (an NO radical scavenger). In contrast, the induced radio- and heat-resistance was not observed under similar conditions in mp53 cells. Moreover, heat-resistance as well as radio-resistance developed when wtp53 cells were treated with ISDN (an NO generating agent) alone. These findings suggest that NO radicals are an initiator of radio- and heat-resistance, and function through the activation of HDM2 and the depression of p53 accumulation.

  18. Comparative clinical evaluation of removable partial dentures made of two different materials in Kennedy Applegate class II partially edentulous situation

    PubMed Central

    Hundal, Maninder; Madan, Rajesh

    2015-01-01

    Background Cast Chromium Cobalt alloy has been the material of choice for fabricating Removable Partial Dentures (RPDs) but has certain drawbacks. Newer materials like the flexible Nylon based Super Polyamide have been introduced to overcome these drawbacks. The present study has compared the above two materials for nine clinical parameters. Method The study was carried out on 30 patients presenting with a Kennedy Applegate class II partially edentulous situation who were divided into two equal groups and clinically assessed. Result Statistically significant results were obtained in favor of flexible RPDs, in the parameters of ‘aesthetics’ and ‘overall patient satisfaction’. Both groups showed more or less similar values for ‘frequency of fracture of the prosthesis during usage’ with the incidence being slightly higher for patients wearing the cast RPDs. The clinical parameters of ‘oral soft tissue tolerance’, ‘gingival health’, ‘periodontal health’ and ‘adaptability in areas with undercut’ were statistically at par for all the 30 patients thus suggesting the comparable biocompatibility of the two materials. The highlight of this study was the relative ease in fabrication of the flexible RPDs as compared to the cast RPDs. Conclusion Based on the favorable clinical results of this study, it can be summarized that the flexible RPDs is a viable alternative to cast RPDs in Kennedy Applegate class II partially edentulous situation in the short term. PMID:26843744

  19. Fire and heat resistant laminating resins based on maleimido substituted aromatic cyclotriphosphazene polymer

    NASA Technical Reports Server (NTRS)

    Kumar, Devendra (Inventor); Fohlen, George M. (Inventor); Parker, John A. (Inventor)

    1987-01-01

    4-Aminophenoxy cyclotriphosphazenes are reacted with maleic anhydride to produce maleamic acids which are converted to the maleimides. The maleimides are polymerized. By selection of starting materials (e.g., hexakis amino or trisaminophenoxy trisphenoxy cyclotriphosphazenes), selection of molar proportions of reactants, use of mixtures of anhydrides and use of dianhydrides as bridging groups a variety of maleimides and polymers are produced. The polymers have high limiting oxygen indices, high char yields and other useful heat and fire resistant properties making them useful as, for example, impregnants of fabrics.

  20. Dry-heat Resistance of Bacillus Subtilis Var. Niger Spores on Mated Surfaces

    NASA Technical Reports Server (NTRS)

    Simko, G. J.; Devlin, J. D.; Wardle, M. D.

    1971-01-01

    Bacillus subtilis var. niger spores were placed on the surfaces of test coupons manufactured from typical spacecraft materials including stainless steel, magnesium, titanium, and aluminum. These coupons were then juxtaposed at the inoculated surfaces and subjected to test pressures of 0, 1000, 5000, and 10,000 psi. Tests were conducted in ambient, nitrogen, and helium atmospheres. While under the test pressure condition, the spores were exposed to 125 C for intervals of 5, 10, 20, 50, or 80 min. Survivor data were subjected to a linear regression analysis that calculated decimal reduction times.

  1. A 31 mW, 280 fs passively mode-locked fiber soliton laser using a high heat-resistant SWNT/P3HT saturable absorber coated with siloxane.

    PubMed

    Ono, Takato; Hori, Yuichiro; Yoshida, Masato; Hirooka, Toshihiko; Nakazawa, Masataka; Mata, Junji; Tsukamoto, Jun

    2012-10-08

    We report a substantial increase in the heat resistance in a connector-type single-wall carbon nanotube (SWNT) saturable absorber by sealing SWNT/P3HT composite with siloxane. By applying the saturable absorber to a passively mode-locked Er fiber laser, we successfully demonstrated 280 fs, 31 mW pulse generation with a fivefold improvement in heat resistance.

  2. Robust, heat-resistant and multifunctional superhydrophobic coating of carbon microflowers with molybdenum trioxide nanoparticles.

    PubMed

    Wu, Yang; Zhao, Meiyun; Guo, Zhiguang

    2017-11-15

    Superhydrophobic materials have triggered large interest due to their widespread applications, such as self-cleaning, corrosion resistance, anti-icing, and oil/water separation. However, suffering from weak mechanical strength, plenty of superhydrophobic materials are limited in practical application. Herein, we prepared hierarchical carbon microflowers (CMF) dispersed with molybdenum trioxide (MoO3) nanoparticles (MoO3/CMF) via a two-step preparation method. Taking advantage of high-adhesion epoxy resin and the modification with 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PDES), the modified MoO3/CMF (PDES-MoO3/CMF) coating on various substrates shows great waterproof ability, excellent chemical stability, good mechanical durability, and self-cleaning property. More significantly, the prepared PDES-MoO3/CMF powder with high thermal stability (250°C) can be used for oil/water separation due to its special flower-like structure and superhydrophobicity/superoleophilicity. All of these advantages endow the superhydrophobic powders with huge potential in the practical applications. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Preparation and characterization of trihydroxamic acid functionalized carbon materials for the removal of Cu(II) ions from aqueous solution

    NASA Astrophysics Data System (ADS)

    Godino-Salido, M. Luz; Santiago-Medina, Antonio; López-Garzón, Rafael; Gutiérrez-Valero, María D.; Arranz-Mascarós, Paloma; López de la Torre, M. Dolores; Domingo-García, María; López-Garzón, F. Javier

    2016-11-01

    The main objective of this study is to prepare and characterize two functionalizated carbon materials with enhanced adsorptive properties for Cu(II). Thus, two novel hybrid materials have been prepared by a non-covalent functionalization method based on the adsorption of a pyrimidine-desferrioxamine-B conjugate compound (H4L) on two activated carbons, ACs (labelled Merck and F). The adsorption of H4L on the ACs is pH-dependent and highly irreversible. This is due to strong π-π interactions between the arene centers of the ACs and the pyrimidine moiety of H4L. The textural characterization of the AC/H4L hybrids shows large decreases of their surface areas. Thus the values of Merck and F are 1031 and 1426 m2/g respectively, while these of Merck/H4L and F/H4L hybrids are 200 and 322 m2/g. An important decrease in the micropore volumes is also found, due to the blockage of narrow porosity produced by the adsorption of H4L molecules. The ACs/H4L hybrids show larger adsorption capacities for Cu(II) (0.105(4) and 0.13(2) mmol/g, at pH 2.0, and 0.20(3) and 0.242(9) mmol/g, at pH 5.5, for Merck/H4L and F/H4L, respectively) than those of the ACs (0.024(6) and 0.096(9) mmol/g, at pH 2.0, and 0.10(2) and 0.177(8) mmol/g, at pH 5.5, for Merck and F respectively), which is explained on the basis of the complexing ability of the trihydroxamic acid functions. The desorption of Cu(II) from the ACs/H4L/Cu(II) materials in acid solution allows the regeneration of most active sites (78.5% in the case of Merck/H4L/Cu(II) and 83.0% in the case of F/H4L/Cu(II)).

  4. Accelerated Sorption Diffusion for Cu(II) Retention by Anchorage of Nano-zirconium Dioxide onto Highly charged Polystyrene Material

    PubMed Central

    Zhang, Qingrui; Du, Qing; Jiao, Tifeng; Teng, Jie; Sun, Qina; Peng, Qiuming; Chen, Xinqing; Gao, Faming

    2015-01-01

    The development of nanocomposite with strong adsorption ability exhibits great potential applications for environmental remediation. However, the pore blocking in preparation frequently constrains sorption diffusion, resulting in low utilization efficiency. Here we synthesized a new nano-ZrO2/Polystyrene (NZO-PS) material tailored with a specific fixed SO3-Na group to enhance Cu(II) removal. The NZO-PS exhibits efficient Cu(II) sequestration in a wide pH range (3.0–6.5) and preferential sorption performances. The efficient kinetic behavior and column applicability suggest the blocked pore channel is not a matter when presence of negatively charged moiety, which accelerates Cu(II) sorption diffusion and enrichment toward target active site. Moreover, the exhausted NZO-PS can be readily regenerated through HCl-NaCl binary solution. The preparation route can be extended to synthesize other functional composited materials. Simultaneously, the characteristics of simplicity, high-yield and regeneration provide some promising industrial merits. PMID:26184921

  5. Removal of Cd (II) from synthetic wastewater by alginate-Ayous wood sawdust (Triplochiton scleroxylon) composite material.

    PubMed

    Njimou, Jacques Romain; Măicăneanu, Andrada; Indolean, Cerasella; Nanseu-Njiki, Charles Péguy; Ngameni, Emmanuel

    2016-01-01

    The biosorption characteristics of Cd (II) ions from synthetic wastewater using raw Ayous wood sawdust (Triplochiton scleroxylon), r-AS, immobilized by sodium alginate were investigated with respect to pH, biomass quantity, contact time, initial concentration of heavy metal, temperature and stirring rate. The experimental data fitted well with the Langmuir isotherm, suggesting that monolayer adsorption of the cadmium ions onto alginate-Ayous sawdust composite (a-ASC). The obtained monolayer adsorption capacity of a-ASC for Cd (II) was 6.21 mg/g. From the Dubinin-Radushkevich isotherm model, a 5.39 kJ/mol value for the mean free energy was calculated, indicating that Cd (II) biosorption could include an important physisorption stage. Thermodynamic calculations showed that the Cd (II) biosorption process was feasible, endothermic and spontaneous in nature under examined conditions. The results indicated that a-ASC could be an alternative material replacing more costly adsorbents used for the removal of heavy metals.

  6. Multiply fully recyclable carbon fibre reinforced heat-resistant covalent thermosetting advanced composites.

    PubMed

    Yuan, Yanchao; Sun, Yanxiao; Yan, Shijing; Zhao, Jianqing; Liu, Shumei; Zhang, Mingqiu; Zheng, Xiaoxing; Jia, Lei

    2017-03-02

    Nondestructive retrieval of expensive carbon fibres (CFs) from CF-reinforced thermosetting advanced composites widely applied in high-tech fields has remained inaccessible as the harsh conditions required to recycle high-performance resin matrices unavoidably damage the structure and properties of CFs. Degradable thermosetting resins with stable covalent structures offer a potential solution to this conflict. Here we design a new synthesis scheme and prepare a recyclable CF-reinforced poly(hexahydrotriazine) resin matrix advanced composite. The multiple recycling experiments and characterization data establish that this composite demonstrates performance comparable to those of its commercial counterparts, and more importantly, it realizes multiple intact recoveries of CFs and near-total recycling of the principal raw materials through gentle depolymerization in certain dilute acid solution. To our best knowledge, this study demonstrates for the first time a feasible and environment-friendly preparation-recycle-regeneration strategy for multiple CF-recycling from CF-reinforced advanced composites.

  7. Heat treating of a lamellar eutectic alloy (gamma/gamma prime + delta). [heat resistant alloys

    NASA Technical Reports Server (NTRS)

    Tewari, S. N.; Dreshfield, R. L.

    1976-01-01

    Eutectic superalloys are being developed at several laboratories for application as aircraft gas turbine airfoils. One such alloy was subjected to several heat treatments to determine if its mechanical properties could be improved. It was found that by partially dissolving the alloy at 1210 C and then aging at 900 C the tensile strength can be increased about 12 percent at temperatures up to 900 C. At 1040 C no change in tensile strength was observed. Times to rupture were measured between 760 and 1040 C and were essentially the same or greater than for as-grown material. Tensile and rupture ductility of the alloy are reduced by heat treatment. Photographs of the microstructure are shown.

  8. Multiply fully recyclable carbon fibre reinforced heat-resistant covalent thermosetting advanced composites

    NASA Astrophysics Data System (ADS)

    Yuan, Yanchao; Sun, Yanxiao; Yan, Shijing; Zhao, Jianqing; Liu, Shumei; Zhang, Mingqiu; Zheng, Xiaoxing; Jia, Lei

    2017-03-01

    Nondestructive retrieval of expensive carbon fibres (CFs) from CF-reinforced thermosetting advanced composites widely applied in high-tech fields has remained inaccessible as the harsh conditions required to recycle high-performance resin matrices unavoidably damage the structure and properties of CFs. Degradable thermosetting resins with stable covalent structures offer a potential solution to this conflict. Here we design a new synthesis scheme and prepare a recyclable CF-reinforced poly(hexahydrotriazine) resin matrix advanced composite. The multiple recycling experiments and characterization data establish that this composite demonstrates performance comparable to those of its commercial counterparts, and more importantly, it realizes multiple intact recoveries of CFs and near-total recycling of the principal raw materials through gentle depolymerization in certain dilute acid solution. To our best knowledge, this study demonstrates for the first time a feasible and environment-friendly preparation-recycle-regeneration strategy for multiple CF-recycling from CF-reinforced advanced composites.

  9. Novel heat-resistance UV curable waterborne polyurethane coatings modified by melamine

    NASA Astrophysics Data System (ADS)

    Fang, Z. H.; Duan, H. Y.; Zhang, Z. H.; Wang, J.; Li, D. Q.; Huang, Y. X.; Shang, J. J.; Liu, Z. Y.

    2011-03-01

    Novel UV curable waterborne polyurethane coatings (UVWPU) modified by melamine was prepared using isophorone diisocyanate (IPDI), polyethylene glycol (PEG), α,α-dimethylol propionic acid (DMPA), hydroxyethyl acrylate (HEA) as main materials. Copolymer structure was verified using Fourier transform infrared spectroscopy (FT-IR). Performance of the coatings was evaluated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), and mechanical tests such as pencil hardness and resistance to water. The results showed that the modified UVWPU film had the good thermal resistance, water resistance and mechanical properties. The optimum melamine dosage was 4.70 wt.%, the glass transition temperature ( Tg) of the modified film increased by 20.4 °C and 5% weight-loss temperature (253 °C) increased by 105 °C. No change color, crinkle, desquamate, dehisce and frothy were found after the modified film dried at 130 °C for 2 h.

  10. Multiply fully recyclable carbon fibre reinforced heat-resistant covalent thermosetting advanced composites

    PubMed Central

    Yuan, Yanchao; Sun, Yanxiao; Yan, Shijing; Zhao, Jianqing; Liu, Shumei; Zhang, Mingqiu; Zheng, Xiaoxing; Jia, Lei

    2017-01-01

    Nondestructive retrieval of expensive carbon fibres (CFs) from CF-reinforced thermosetting advanced composites widely applied in high-tech fields has remained inaccessible as the harsh conditions required to recycle high-performance resin matrices unavoidably damage the structure and properties of CFs. Degradable thermosetting resins with stable covalent structures offer a potential solution to this conflict. Here we design a new synthesis scheme and prepare a recyclable CF-reinforced poly(hexahydrotriazine) resin matrix advanced composite. The multiple recycling experiments and characterization data establish that this composite demonstrates performance comparable to those of its commercial counterparts, and more importantly, it realizes multiple intact recoveries of CFs and near-total recycling of the principal raw materials through gentle depolymerization in certain dilute acid solution. To our best knowledge, this study demonstrates for the first time a feasible and environment-friendly preparation-recycle-regeneration strategy for multiple CF-recycling from CF-reinforced advanced composites. PMID:28251985

  11. Industry to Education Technical Transfer Program & Composite Materials. Composite Materials Course. Fabrication I Course. Fabrication II Course. Composite Materials Testing Course. Final Report.

    ERIC Educational Resources Information Center

    Massuda, Rachel

    These four reports provide details of projects to design and implement courses to be offered as requirements for the associate degree program in composites and reinforced plastics technology. The reports describe project activities that led to development of curricula for four courses: composite materials, composite materials fabrication I,…

  12. Project Care Phase II: A Case Study in the Evaluation of Communication and Learning Materials.

    ERIC Educational Resources Information Center

    Williams, Frederick; And Others

    Phase II was a field evaluation of a communication and learning system package of films, simulation games, discussion questions, and posters designed to promote career awareness in junior high school children. It was proposed that this evaluation serves as a prototype for the assessment of the effects of learning systems on the affective and…

  13. Restoration of non-carious cervical lesions Part II. Restorative material selection to minimise fracture.

    PubMed

    Ichim, I P; Schmidlin, P R; Li, Q; Kieser, J A; Swain, M V

    2007-12-01

    It is still largely unknown as to what material parameter requirements would be most suitable to minimise the fracture and maximising the retention rate of the restoration of cervical non-carious lesions (NCCL). The present paper, as a first of its kind, proposes a radical approach to address the problems of material improvement, namely: numerical-based, fracture and damage mechanics materials optimisation engineering. It investigates the influence of the elastic modulus (E) on the failure of cervical restorative materials and aims to identify an E value that will minimise mechanical failure under clinically realistic loading conditions. The present work relies on the principle that a more flexible restorative material would partially buffer the local stress concentration. We employ a "most favourable" parametric analysis of the restorative's elastic modulus using a fracture mechanics model embedded into finite element method. The advanced numerical modelling adopts a Rankine and rotating crack material fracture model coupled to a non-linear analysis in an explicit finite element framework. The present study shows that the restorative materials currently used in non-carious cervical lesions are largely unsuitable in terms of resistance to fracture of the restoration and we suggest that the elastic modulus of such a material should be in the range of 1GPa. We anticipate that the presented methodology would provide more informative guidelines for the development of dental restorative materials, which could be tailored to specific clinical applications cognisant of the underlying mechanical environment.

  14. INFORMATION: Inspection Report on "Removal of Categories I and II Special Nuclear Material from Sandia National Laboratories-New Mexico"

    SciTech Connect

    2010-01-01

    The Department of Energy's (DOE's) Sandia National Laboratories-New Mexico (Sandia) develops science-based technologies in support of national security in areas such as nuclear weapons, nonproliferation, military technologies, and homeland security. Sandia's primary mission is ensuring that the U.S. nuclear arsenal is safe, secure, and reliable and can fully support the Nation's deterrence policy. Part of this mission includes systems engineering of nuclear weapons; research, design, and development of non-nuclear components; manufacturing of non-nuclear weapons components; the provision of safety, security, and reliability assessments of stockpile weapons; and the conduct of high-explosives research and development and environmental testing. Sandia Corporation, a subsidiary of Lockheed Martin Corporation, operates Sandia for the National Nuclear Security Administration (NNSA). On May 7, 2004, the Secretary announced that the Department would evaluate missions at DOE sites to consolidate Special Nuclear Material (SNM) in the most secure environments possible. The Administrator of the NNSA said that this effort was a key part of an overall plan to transform the nuclear weapons complex into a smaller, safer, more secure, and more efficient national security enterprise. In February 2008, Sandia was the first site to report it had reduced its on-site inventory of nuclear material below 'Categories I and II' levels, which require the highest level of security to protect material such as plutonium and highly enriched uranium. The Office of Inspector General initiated an inspection to determine if Sandia made appropriate adjustments to its security posture in response to the removal of the Categories I and II SNM. We found that Sandia adjusted its security posture in response to the removal of Categories I and II SNM. For example, security posts were closed; unneeded protective force weapons and equipment were excessed from the site; and, Sandia's Site Safeguards and

  15. Population and Family Education. Book II. Draft Sample Instructional Materials. Social Studies.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Bangkok (Thailand). Regional Office for Education in Asia and Oceania.

    Produced by participants at the Unesco Regional workshop on Population and Family Education held in Bangkok, Thailand, in October 1970, the instructional materials intended for elementary and secondary students are to be considered sample first-draft materials usable for reference purposes by groups responsible for designing population education…

  16. Hydrated silica exterior produced by biomimetic silicification confers viral vaccine heat-resistance.

    PubMed

    Wang, Guangchuan; Wang, Hong-Jiang; Zhou, Hangyu; Nian, Qing-Gong; Song, Zhiyong; Deng, Yong-Qiang; Wang, Xiaoyu; Zhu, Shun-Ya; Li, Xiao-Feng; Qin, Cheng-Feng; Tang, Ruikang

    2015-01-27

    Heat-lability is a key roadblock that strangles the widespread applications of many biological products. In nature, archaeal and extremophilic organisms utilize amorphous silica as a protective biomineral and exhibit considerable thermal tolerance. Here we present a bioinspired approach to generate thermostable virus by introducing an artificial hydrated silica exterior on individual virion. Similar to thermophiles, silicified viruses can survive longer at high temperature than their wild-type relatives. Virus inactivation assays showed that silica hydration exterior of the modified virus effectively prolonged infectivity of viruses by ∼ 10-fold at room temperature, achieving a similar result as that obtained by storing native ones at 4 °C. Mechanistic studies indicate that amorphous silica nanoclusters stabilize the inner virion structure by forming a layer that restricts molecular mobility, acting as physiochemical nanoanchors. Notably, we further evaluate the potential application of this biomimetic strategy in stabilizing clinically approved vaccine, and the silicified polio vaccine that can retain 90% potency after the storage at room temperature for 35 days was generated by this biosilicification approach and validated with in vivo experiments. This approach not only biomimetically connects inorganic material and living virus but also provides an innovative resolution to improve the thermal stability of biological agents using nanomaterials.

  17. Elastico-mechanoluminescence and crystal-structure relationships in persistent luminescent materials and II-VI semiconductor phosphors

    NASA Astrophysics Data System (ADS)

    Chandra, B. P.; Chandra, V. K.; Jha, Piyush

    2015-04-01

    Elastico-mechanoluminescence (EML) has recently attracted the attention of a large number of researchers because of its potential in different types of mechano-optical devices. For understanding the mechanism of EML the relationships between elastico-mechanoluminescence (EML) and crystal-structure of a large number of persistent luminescent materials and II-VI semiconductor phosphors known to date are investigated. It is found that, although most of the non-centrosymmetric crystals exhibit EML, certain non-centrosymmetric crystals do not show EML. Whereas, many centrosymmetric crystals do not exhibit EML, certain centrosymmetric crystals exhibit EML. Piezoelectric ZnS:Cu,Cl single crystals do not show EML, but piezoelectric ZnS:Cu,Cl microcrystalline phosphors show very intense EML. Piezoelectric single crystals of undoped ZnS do not show EML. It seems that EML is related to local piezoelectrification near the impurities in crystals where piezoelectric constant is high. Suitable piezoelectric field near the local piezoelectric region and stable charge carriers in traps are required for appearance of EML. The EML of persistent luminescent materials and II-VI semiconductor phosphors can be understood on the basis of piezoelectrically-induced trap-depth reduction model of EML. Using suitable dopants both in non-centrosymmetric and centrosymmetric crystals intense elastico-mechanoluminescent materials emitting desired colours can be tailored, which may find applications in several mechano-optical devices.

  18. Copper(I) and copper(II) uranyl heterometallic hybrid materials.

    PubMed

    Weng, Zhehui; Zhang, Zhi-hui; Olds, Travis; Sterniczuk, Marcin; Burns, Peter C

    2014-08-04

    Two copper-uranium heterometallic compounds, [(UO2)3Cu(II)O2(C6NO2)5] (1) and [(UO2)Cu(I)(C6NO2)3] (2), have been synthesized by the reaction of uranyl acetate with copper salts in the presence of isonicotinic acid. Both compounds have been characterized by single-crystal X-ray diffraction, IR, Raman, and UV-vis spectroscopy. In compound 1, interactions between copper and uranium centers occur and result in a three-dimensional pillar layered structure. Compound 1 is also the first example of a heterometallic uranyl organic framework with a trinuclear U3O18 building block. Compound 2 is the first uranyl organic framework that contains monovalent copper, which arises from the reaction of Cu(II) chloride and is assumed to be due to the oxidation of chloride at low pH.

  19. Novel type-II material system for laser applications in the near-infrared regime

    PubMed Central

    Berger, C.; Möller, C.; Hens, P.; Fuchs, C.; Stolz, W.; Koch, S. W.; Ruiz Perez, A.; Hader, J.; Moloney, J. V.

    2015-01-01

    The design and experimental realization of a type-II “W”-multiple quantum well heterostructure for emission in the λ > 1.2 μm range is presented. The experimental photoluminescence spectra for different excitation intensities are analyzed using microscopic quantum theory. On the basis of the good theory–experiment agreement, the gain properties of the system are computed using the semiconductor Bloch equations. Gain values comparable to those of type-I systems are obtained. PMID:25874159

  20. Phosphorous and aluminum gettering in Silicon-Film{trademark} Product II material

    SciTech Connect

    Cotter, J.E.; Barnett, A.M.; Hall, R.B.

    1995-08-01

    Gettering processes are being developed for the Silicon-Film{trademark} Product II solar cell structure. These processes have been developed specifically for films of silicon grown on dissimilar substrates with barrier layers. Gettering with both phosphorous- and aluminum-based processing sequences has resulted in enhancement of minority carrier diffusion length. Long diffusion lengths have allowed the characterization of light trapping in thin films of silicon grown on barrier-coated substrates.

  1. Evaluation of cavity wall adaptation of bulk esthetic materials to restore class II cavities in primary molars.

    PubMed

    Gaintantzopoulou, Maria D; Gopinath, Vellore K; Zinelis, Spiros

    2017-05-01

    The purpose of the study was to assess the cavity wall adaptation and gap formation of a bulk fill composite resin and reinforced conventional glass ionomer cement and a resin-modified glass ionomer cement in class II restorations on primary molars. Standardized class II slot cavity preparations were prepared in exfoliating primary molars. Teeth were restored with one of the three tested materials (n = 10): SonicFill bulk fill composite resin (SF), EQUIA Fil conventional reinforced glass ionomer cement (EQF), and Vitremer resin-reinforced glass ionomer cement (VT). Cavity wall adaptation of the restorations was investigated by computerized X-ray micro-tomography and the percentage void volume fraction (%VVF) was calculated. Same specimens were sectioned and the interfaces were evaluated by reflection optical microscopy to measure the percentage linear length (%LD) of the interfacial gaps. Samples were further evaluated by environmental scanning electron microscopy (ESEM). EQF and SF showed significantly lower %VVF and %LD values than VT (p < 0.05). This was in accordance with ESEM findings where VT illustrated extended interfacial gaps. SF and EQF showed better cavity wall adaptation than VT in class II restorations on primary molars. High-strength conventional glass ionomer cement (GIC EQF) and bulk fill composite SF requiring fewer application steps and reduced operating time than the traditional composite resin materials showed good cavity wall adaptation. Short operating time and good cavity wall adaptation are advantages of the materials in restorative and pediatric dentistry, especially while working on children with limited attention span.

  2. Materials Science and Technology, Volume 17B, Processing of Ceramics Part II

    NASA Astrophysics Data System (ADS)

    Brook, Richard J.

    1996-12-01

    Progress in the processing of ceramics has made these materials very important for current and future technologies. Internationally renowned experts have contributed to this second of two volumes which provide a wealth of information indispensable for materials scientists and engineers. Contents of Volume B: Riedel: Advanced Ceramics from Inorganic Polymers. Calvert: Biomimetic Processing. Eisele: Sintering and Hot Pressing. Kwon: Liquid-Phase Sintering. Leriche/Cambier: Vitrification. Larker/Larker: Hot Isostatic Pressing. Harmer/Chan: Fired Microstructures and Their Charactzerization. Subramanian: Finishing. Nicholas: Joining of Ceramics. Hirai: Functional Gradient Materials.

  3. Maturation of Released Spores Is Necessary for Acquisition of Full Spore Heat Resistance during Bacillus subtilis Sporulation ▿

    PubMed Central

    Sanchez-Salas, Jose-Luis; Setlow, Barbara; Zhang, Pengfei; Li, Yong-qing; Setlow, Peter

    2011-01-01

    The first ∼10% of spores released from sporangia (early spores) during Bacillus subtilis sporulation were isolated, and their properties were compared to those of the total spores produced from the same culture. The early spores had significantly lower resistance to wet heat and hypochlorite than the total spores but identical resistance to dry heat and UV radiation. Early and total spores also had the same levels of core water, dipicolinic acid, and Ca and germinated similarly with several nutrient germinants. The wet heat resistance of the early spores could be increased to that of total spores if early spores were incubated in conditioned sporulation medium for ∼24 h at 37°C (maturation), and some hypochlorite resistance was also restored. The maturation of early spores took place in pH 8 buffer with Ca2+ but was blocked by EDTA; maturation was also seen with early spores of strains lacking the CotE protein or the coat-associated transglutaminase, both of which are needed for normal coat structure. Nonetheless, it appears to be most likely that it is changes in coat structure that are responsible for the increased resistance to wet heat and hypochlorite upon early spore maturation. PMID:21821751

  4. Sustainable, heat-resistant and flame-retardant cellulose-based composite separator for high-performance lithium ion battery

    PubMed Central

    Zhang, Jianjun; Yue, Liping; Kong, Qingshan; Liu, Zhihong; Zhou, Xinhong; Zhang, Chuanjian; Xu, Quan; Zhang, Bo; Ding, Guoliang; Qin, Bingsheng; Duan, Yulong; Wang, Qingfu; Yao, Jianhua; Cui, Guanglei; Chen, Liquan

    2014-01-01

    A sustainable, heat-resistant and flame-retardant cellulose-based composite nonwoven has been successfully fabricated and explored its potential application for promising separator of high-performance lithium ion battery. It was demonstrated that this flame-retardant cellulose-based composite separator possessed good flame retardancy, superior heat tolerance and proper mechanical strength. As compared to the commercialized polypropylene (PP) separator, such composite separator presented improved electrolyte uptake, better interface stability and enhanced ionic conductivity. In addition, the lithium cobalt oxide (LiCoO2)/graphite cell using this composite separator exhibited better rate capability and cycling retention than that for PP separator owing to its facile ion transport and excellent interfacial compatibility. Furthermore, the lithium iron phosphate (LiFePO4)/lithium cell with such composite separator delivered stable cycling performance and thermal dimensional stability even at an elevated temperature of 120°C. All these fascinating characteristics would boost the application of this composite separator for high-performance lithium ion battery. PMID:24488228

  5. Reduction of Intergranular Cracking Susceptibility by Precipitation Control in 2.25Cr Heat-Resistant Steels

    NASA Astrophysics Data System (ADS)

    Sung, Hyun Je; Heo, Nam Hoe; Kim, Sung-Joon

    2017-03-01

    This research is performed to decrease reheat cracking susceptibility in the T/P23 heat-resistant steels (2.25Cr1.5WVNbTi), in other words, to reduce phosphorus and sulfur segregation concentration at the prior austenite grain boundary/carbide interfaces (GCIs) and the carbide-free prior austenite grain boundaries (carbide-free PAGBs) causing intergranular cracking. The increase of bulk vanadium content reduces the amount of M23C6 carbides consuming carbon atoms which can repulse phosphorus and sulfur from interfaces, but promotes the precipitation reaction of V-rich MX carbo-nitrides. Such a precipitation reaction results in the lower segregation concentration of phosphorus or no sulfur at the GCIs and the carbide-free PAGBs. This is because the carbon atoms remaining after precipitation reaction segregates to the interfaces and repels phosphorus and sulfur. Also, tungsten segregation can increase the cohesive grain boundary strength as one of the grain boundary strengtheners. Consequently, the lower segregation concentration of the impurities and the segregation of tungsten atoms lower the intergranular cracking susceptibility.

  6. Isolation and characterization of heat resistant enterotoxigenic Staphylococcus aureus from a food poisoning outbreak in Indian subcontinent.

    PubMed

    Nema, Vijay; Agrawal, Ranu; Kamboj, Dev Vrat; Goel, Ajay Kumar; Singh, Lokendra

    2007-06-10

    Outbreaks of staphylococcal food poisoning (SFP) are very common across the world; however, there is hardly any report of SFP from the Indian subcontinent. An outbreak occurred in the state of Madhya Pradesh (India) after the consumption of a snack called "Bhalla" made up of potato balls fried in vegetable oil. More than 100 children and adults who ate the snack suffered from the typical symptoms of SFP and required hospitalization. Food and clinical samples were found to contain a large number of enterotoxigenic Staphylococcus aureus. All enterotoxigenic isolates produced a combination of SEB and SED enterotoxins and were sensitive to oxacillin and vancomycin. Isolates were characterized by molecular biology tools, viz., SDS-PAGE, amplified ribosomal DNA restriction analysis (ARDRA), randomly amplified polymorphic DNA (RAPD) and nucleotide sequencing of seb, sed, and 16S rDNA genes. Results of these studies suggested that the isolates, irrespective of their isolation from food or clinical samples, were clonal in origin. Further, seb gene sequence of isolates showed nucleotide variations at multiple sites when compared with other sequences available in the database. Representative isolates, one each from food and clinical samples, were found to be highly heat resistant (D(60) approximately 15-16 min). Isolates obtained in the current outbreak need to be further studied to find out the impact on food safety guidelines with respect to thermal processing.

  7. Sustainable, heat-resistant and flame-retardant cellulose-based composite separator for high-performance lithium ion battery

    NASA Astrophysics Data System (ADS)

    Zhang, Jianjun; Yue, Liping; Kong, Qingshan; Liu, Zhihong; Zhou, Xinhong; Zhang, Chuanjian; Xu, Quan; Zhang, Bo; Ding, Guoliang; Qin, Bingsheng; Duan, Yulong; Wang, Qingfu; Yao, Jianhua; Cui, Guanglei; Chen, Liquan

    2014-02-01

    A sustainable, heat-resistant and flame-retardant cellulose-based composite nonwoven has been successfully fabricated and explored its potential application for promising separator of high-performance lithium ion battery. It was demonstrated that this flame-retardant cellulose-based composite separator possessed good flame retardancy, superior heat tolerance and proper mechanical strength. As compared to the commercialized polypropylene (PP) separator, such composite separator presented improved electrolyte uptake, better interface stability and enhanced ionic conductivity. In addition, the lithium cobalt oxide (LiCoO2)/graphite cell using this composite separator exhibited better rate capability and cycling retention than that for PP separator owing to its facile ion transport and excellent interfacial compatibility. Furthermore, the lithium iron phosphate (LiFePO4)/lithium cell with such composite separator delivered stable cycling performance and thermal dimensional stability even at an elevated temperature of 120°C. All these fascinating characteristics would boost the application of this composite separator for high-performance lithium ion battery.

  8. Screening foods for processing-resistant bacterial spores and characterization of a pressure- and heat-resistant Bacillus licheniformis isolate.

    PubMed

    Ahn, Juhee; Balasubramaniam, V M

    2014-06-01

    This study was carried out to isolate pressure- and heat-resistant indicator spores from selected food matrices (black pepper, red pepper, garlic, and potato peel). Food samples were processed under various thermal (90 to 105°C) and pressure (700 MPa) combination conditions, and surviving microorganisms were isolated. An isolate from red pepper powder, Bacillus licheniformis, was highly resistant to pressure-thermal treatments. Spores of the isolate in deionized water were subjected to the combination treatments of pressure (0.1 to 700 MPa) and heat (90 to 121°C). Compared with the thermal treatment, the combined pressure-thermal treatments considerably reduced the numbers of B. licheniformis spores to less than 1.0 log CFU/g at 700 MPa plus 105°C and at 300 to 700 MPa plus 121°C. The inactivation kinetic parameters of the isolated B. licheniformis spores were estimated using linear and nonlinear models. Within the range of the experimental conditions tested, the pressure sensitivity (zP) of the spores decreased with increasing temperature (up to 121°C), and the temperature sensitivity (zT) was maximum at atmospheric pressure (0.1 MPa). These results will be useful for developing a combined pressure-thermal inactivation kinetics database for various bacterial spores.

  9. Precipitation behavior and martensite lath coarsening during tempering of T/P92 ferritic heat-resistant steel

    NASA Astrophysics Data System (ADS)

    Xu, Lin-qing; Zhang, Dan-tian; Liu, Yong-chang; Ning, Bao-qun; Qiao, Zhi-xia; Yan, Ze-sheng; Li, Hui-jun

    2014-05-01

    Tempering is an important process for T/P92 ferritic heat-resistant steel from the viewpoint of microstructure control, as it facilitates the formation of final tempered martensite under serving conditions. In this study, we have gained deeper insights on the mechanism underlying the microstructural evolution during tempering treatment, including the precipitation of carbides and the coarsening of martensite laths, as systematically analyzed by optical microscopy, transmission electron microscopy, and high-resolution transmission electron microscopy. The chemical composition of the precipitates was analyzed using energy dispersive X-ray spectroscopy. Results indicate the formation of M3C (cementite) precipitates under normalized conditions. However, they tend to dissolve within a short time of tempering, owing to their low thermal stability. This phenomenon was substantiated by X-ray diffraction analysis. Besides, we could observe the precipitation of fine carbonitrides (MX) along the dislocations. The mechanism of carbon diffusion controlled growth of M23C6 can be expressed by the Zener's equation. The movement of Y-junctions was determined to be the fundamental mechanism underlying the martensite lath coarsening process. Vickers hardness was estimated to determine their mechanical properties. Based on the comprehensive analysis of both the micro-structural evolution and hardness variation, the process of tempering can be separated into three steps.

  10. Influence of high temperature pre-deformation on the dissolution rate of delta ferrites in martensitic heat-resistant steels

    NASA Astrophysics Data System (ADS)

    Li, Junru; Liu, Jianjun; Jiang, Bo; Zhang, Chaolei; Liu, Yazheng

    2017-03-01

    The dissolution process of delta ferrites and the influence of high temperature pre-deformation on the dissolution rate of delta ferrites in martensitic heat-resistant steel 10Cr12Ni3Mo2VN were studied by isothermal heating and thermal simulation experiments. The precipitation temperature of delta ferrites in experimental steel is about 1195 °C. M23C6-type carbides incline to precipitate and coarsen at the boundaries of delta ferrites below 930 °C, and can be rapidly dissolved by heating at 1180 °C. The percentage of delta ferrites gradually decreases with heating time. And a Kolmogorov-Johnson-Mehl-Avrami equation was established to describe the dissolution process of delta ferrites at 1180 °C. High temperature pre-deformation can markedly increase the dissolution rate of delta ferrites. Pre-deformation can largely increase the interface area between delta ferrite and matrix and thus increase the unit-time diffusing quantities of alloying elements between delta ferrites and matrix. In addition, high temperature pre-deformation leads to dynamic recrystallization and increases the number of internal grain boundaries in the delta ferrites. This can also greatly increase the diffusing rate of alloying elements. In these cases, the dissolution of delta ferrites can be promoted.

  11. Reduction of Intergranular Cracking Susceptibility by Precipitation Control in 2.25Cr Heat-Resistant Steels

    NASA Astrophysics Data System (ADS)

    Sung, Hyun Je; Heo, Nam Hoe; Kim, Sung-Joon

    2017-01-01

    This research is performed to decrease reheat cracking susceptibility in the T/P23 heat-resistant steels (2.25Cr1.5WVNbTi), in other words, to reduce phosphorus and sulfur segregation concentration at the prior austenite grain boundary/carbide interfaces (GCIs) and the carbide-free prior austenite grain boundaries (carbide-free PAGBs) causing intergranular cracking. The increase of bulk vanadium content reduces the amount of M23C6 carbides consuming carbon atoms which can repulse phosphorus and sulfur from interfaces, but promotes the precipitation reaction of V-rich MX carbo-nitrides. Such a precipitation reaction results in the lower segregation concentration of phosphorus or no sulfur at the GCIs and the carbide-free PAGBs. This is because the carbon atoms remaining after precipitation reaction segregates to the interfaces and repels phosphorus and sulfur. Also, tungsten segregation can increase the cohesive grain boundary strength as one of the grain boundary strengtheners. Consequently, the lower segregation concentration of the impurities and the segregation of tungsten atoms lower the intergranular cracking susceptibility.

  12. Influence of high temperature pre-deformation on the dissolution rate of delta ferrites in martensitic heat-resistant steels

    NASA Astrophysics Data System (ADS)

    Li, Junru; Liu, Jianjun; Jiang, Bo; Zhang, Chaolei; Liu, Yazheng

    2017-02-01

    The dissolution process of delta ferrites and the influence of high temperature pre-deformation on the dissolution rate of delta ferrites in martensitic heat-resistant steel 10Cr12Ni3Mo2VN were studied by isothermal heating and thermal simulation experiments. The precipitation temperature of delta ferrites in experimental steel is about 1195 °C. M23C6-type carbides incline to precipitate and coarsen at the boundaries of delta ferrites below 930 °C, and can be rapidly dissolved by heating at 1180 °C. The percentage of delta ferrites gradually decreases with heating time. And a Kolmogorov-Johnson-Mehl-Avrami equation was established to describe the dissolution process of delta ferrites at 1180 °C. High temperature pre-deformation can markedly increase the dissolution rate of delta ferrites. Pre-deformation can largely increase the interface area between delta ferrite and matrix and thus increase the unit-time diffusing quantities of alloying elements between delta ferrites and matrix. In addition, high temperature pre-deformation leads to dynamic recrystallization and increases the number of internal grain boundaries in the delta ferrites. This can also greatly increase the diffusing rate of alloying elements. In these cases, the dissolution of delta ferrites can be promoted.

  13. Montmorillonite-Cu(II)/Fe(III) oxides magnetic material as adsorbent for removal of humic acid and its thermal regeneration.

    PubMed

    Peng, Xianjia; Luan, Zhaokun; Zhang, Hongmei

    2006-04-01

    In this work, the adsorption features of montmorillonite and the magnetic properties of Cu(II)/Fe(III) oxides were combined in a material to produce magnetic adsorbent, which can be separated from the medium by a simple magnetic process after adsorption. The magnetic material is effective for the removal of humic acid. At pH 6.1, 96% removal was observed from 4.4 mg l(-1) humic acid solution containing 0.02 M NaCl. The adsorption is pH and ionic strength dependent. Adsorption is favored at lower pH values and dissolved NaCl can enhance the adsorption. The adsorption mechanism of humic acid to the magnetic material was suggested to be the ligand exchange reaction between carboxylic groups of humic acid molecules and the magnetic material surface. The magnetic material can be thermally regenerated. The temperature and time required to achieve good regeneration efficiency were determined to be 300 degrees C and 3 h, respectively. The regenerated adsorbent is still magnetic and approximately has as high specific saturation magnetization and good adsorption capacities as the as-prepared adsorbent.

  14. (Docket A-93-02) Category II-F: Interagency Review Materials

    EPA Pesticide Factsheets

    This Index lists Interagency review materials related to the decision to certify that DOE had met the compliance criteria established by EPA in 40 CFR Part 194 and the disposal regulations set by EPA in 40 CFR Part 191.

  15. In-cell welding fixture. Remote welder assembly, Model II (Engineering Materials)

    SciTech Connect

    Not Available

    1985-02-01

    The remote welder assembly provides the mechanical apparatus for remotely welding cylindrical, metallic capsules containing radioactive materials. It consists of a rotating chuck and welding electrode with positioning controls operable by master-slave manipulators.

  16. Characterizing Materials Sources and Sinks; Current Approaches: Part II. Chemical and Physical Characterization

    EPA Science Inventory

    The paper discusses methods for characterizing chemical emissions from material sources, including laboratory, dynamic chamber, and full-scale studies. Indoor sources and their interaction with sinks play a major role in determining indoor air quality (IAQ). Techniques for evalua...

  17. Magnetic materials based on iron dispersed in graphitic matrices II. High temperatures and mesophase pitch

    NASA Astrophysics Data System (ADS)

    Dyakonov, Alexander J.; Jack McCormick, B.; Kahol, Pawan K.; Hamdeh, Hussein H.

    1997-03-01

    Ferromagnetic materials based on iron incorporated into pitch were synthesized, and characterized by magnetic methods (Faraday), Mössbauer spectroscopy, SEM, and XRD. A graphitic-type structure was observed to form at 350-1650°C. The important role of a mesophase structure of a pitch-precursor in the iron carbonyl absorption and anisotropic structure of the resulting iron containing material was found.

  18. 30 CFR 57.22222 - Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines). 57.22222 Section 57.22222 Mineral Resources MINE SAFETY AND HEALTH....22222 Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines). Brattice cloth and...

  19. 30 CFR 57.22222 - Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines). 57.22222 Section 57.22222 Mineral Resources MINE SAFETY AND HEALTH....22222 Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines). Brattice cloth and...

  20. 30 CFR 57.22222 - Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines). 57.22222 Section 57.22222 Mineral Resources MINE SAFETY AND HEALTH....22222 Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines). Brattice cloth and...

  1. 30 CFR 57.22222 - Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines). 57.22222 Section 57.22222 Mineral Resources MINE SAFETY AND HEALTH....22222 Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines). Brattice cloth and...

  2. 30 CFR 57.22222 - Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines). 57.22222 Section 57.22222 Mineral Resources MINE SAFETY AND HEALTH....22222 Ventilation materials (I-A, I-B, I-C, II-A, III, V-A, and V-B mines). Brattice cloth and...

  3. Coordination Nanosheets Based on Terpyridine-Zinc(II) Complexes: As Photoactive Host Materials.

    PubMed

    Tsukamoto, Takamasa; Takada, Kenji; Sakamoto, Ryota; Matsuoka, Ryota; Toyoda, Ryojun; Maeda, Hiroaki; Yagi, Toshiki; Nishikawa, Michihiro; Shinjo, Naoaki; Amano, Shuntaro; Iokawa, Tadashi; Ishibashi, Narutaka; Oi, Tsugumi; Kanayama, Koshiro; Kinugawa, Rina; Koda, Yoichiro; Komura, Toshiyuki; Nakajima, Shuhei; Fukuyama, Ryota; Fuse, Nobuyuki; Mizui, Makoto; Miyasaki, Masashi; Yamashita, Yutaro; Yamada, Kuni; Zhang, Wenxuan; Han, Ruocheng; Liu, Wenyu; Tsubomura, Taro; Nishihara, Hiroshi

    2017-04-04

    Photoluminescent coordination nanosheets (CONASHs) comprising three-way terpyridine (tpy) ligands and zinc(II) ions are created by allowing the two constitutive components to react with each other at a liquid/liquid interface. Taking advantage of bottom-up CONASHs, or flexibility in organic ligand design and coordination modes, we demonstrate the diversity of the tpy-zinc(II) CONASH in structures and photofunctions. A combination of 1,3,5-tris[4-(4'-2,2':6',2″-terpyridyl)phenyl]benzene (1) and Zn(BF4)2 affords a cationic CONASH featuring the bis(tpy)Zn complex motif (1-Zn), while substitution of the zinc source with ZnSO4 realizes a charge-neutral CONASH with the [Zn2(μ-O2SO2)2(tpy)2] motif [1-Zn2(SO4)2]. The difference stems from the use of noncoordinating (BF4(-)) or coordinating and bridging (SO4(2-)) anions. The change in the coordination mode alters the luminescence (480 nm blue in 1-Zn; 552 nm yellow in 1-Zn2(SO4)2). The photophysical property also differs in that 1-Zn2(SO4)2 shows solvatoluminochromism, whereas 1-Zn does not. Photoluminescence is also modulated by the tpy ligand structure. 2-Zn contains triarylamine-centered terpyridine ligand 2 and features the bis(tpy)Zn motif; its emission is substantially red-shifted (590 nm orange) compared with that of 1-Zn. CONASHs 1-Zn and 2-Zn possess cationic nanosheet frameworks with counteranions (BF4(-)), and thereby feature anion exchange capacities. Indeed, anionic xanthene dyes were taken up by these nanosheets, which undergo quasi-quantitative exciton migration from the host CONASH. This series of studies shows tpy-zinc(II) CONASHs as promising potential photofunctional nanomaterials.

  4. Growth, spectral and thermal studies of an efficient NLO material: Diaquadicinnamatocadmium(II)

    SciTech Connect

    Roy, Sunalya M.; Sudarsanakumar, M. R.; Dhanya, V. S.

    2014-01-28

    A nonlinear metal–organic crystal, diaquadicinnamatocadmium(II) has been grown by controlled gel diffusion technique. Sodium metasilicate was used to prepare the gel. The chemical composition of the crystal has been determined by CHN analysis. Powder X-ray diffraction studies confirm the crystalline nature of the grown crystal. Functional groups present in the compound were identified by FT-IR spectral analysis. The thermal decomposition of the compound was studied using thermogravimetry (TG). The optical transparency range and the lower cut-off wavelength were identified from the UV-Visible-NIR spectrum. The NLO activity of the grown crystal was confirmed using Kurtz and Perry powder test.

  5. Biological induced corrosion of materials II: New test methods and experiences from mir station

    NASA Astrophysics Data System (ADS)

    Klintworth, R.; Reher, H. J.; Viktorov, A. N.; Bohle, D.

    1999-09-01

    During previous long-term manned missions, more than 100 species of microorganisms have been identified on surfaces of materials (bacteria and fungi). Among them were potentially pathogenic ones (saprophytes) which are capable of active growth on artificial substrates, as well as technophilic bacteria and fungi causing damages (destruction and degradation) to various materials (metals and polymers), resulting in failures and disruptions in the functioning of equipment and hardware. Aboard a space vehicle some microclimatic parameters are optimal for microorganism growth: the atmospheric fluid condensate with its specific composition, chemical and/or antropogenic contaminants (human metobolic products, etc.) all are stimulating factors for the development of bacteria and mould fungi on materials of the interior and equipment of an orbital station during its operational phase(s). Especially Russian long-term missions (SALJUT, MIR) have demonstrated that uncontrolled interactions of microorganisms with materials will ultimately lead to the appearence of technological and medical risks, significantly influencing safety and reliability characteristics of individual as well as whole systems and/ or subsystems. For a first conclusion, it could be summarized, that countermeasures and anti-strategies focussing on Microbial Contamination Management (MCM) for the International Space Station (ISS, next long-term manned mission) at least require a new materials test approach. Our respective concept includes a combined age-ing/biocorrosion test sequence. It is represented here, as well as current status of MCM program, e.g. continuous monitoring (microbiological analyses), long-term disinfection, frequent cleaning methods, mathematical modeling of ISS, etc.

  6. Optimisation of integrated biodiesel production. Part II: a study of the material balance.

    PubMed

    Vicente, Gemma; Martínez, Mercedes; Aracil, José

    2007-07-01

    A study was made of the material balance for the fatty acid methyl ester (biodiesel) synthesis from sunflower oil using potassium hydroxide as the catalyst. A factorial design of experiments and a central composite design have been used to evaluate the influence of operating conditions on the process material balance. The responses chosen were the biodiesel yield and the yield losses due to triglyceride saponification and methyl ester dissolution in glycerol, while the variables studied were temperature, initial catalyst concentration and the methanol:vegetable oil molar ratio. The biodiesel yield increased and therefore the yield losses decreased by decreasing catalyst concentration and temperature. However, the methanol:sunflower oil molar ratio did not affect the material balance variables significantly. Second-order models were obtained to predict the biodiesel yield and both yield losses. Within the experimental range studied, these models largely matched the results from the experiments.

  7. Pyrolysis of municipal plastic wastes II: Influence of raw material composition under catalytic conditions

    SciTech Connect

    Lopez, A.

    2011-09-15

    Highlights: > ZSM-5 zeolite catalytic pyrolysis transforms municipal plastic waste into liquids and gases useful as fuels or source of chemicals. > The composition of the waste sample plays an important role on the catalyst activity and the products obtained. > ZSM-5 zeolite is somehow deactivated when high proportions of fine inorganic materials are present in the sample. > When the sample contains cellulose-based materials, the formation of a two-phase liquid fraction can be avoided by a low temperature step. - Abstract: In this work, the results obtained in catalytic pyrolysis of three plastic waste streams which are the rejects of an industrial packing wastes sorting plant are presented. The samples have been pyrolysed in a 3.5 dm{sup 3} reactor under semi-batch conditions at 440 {sup o}C for 30 min in nitrogen atmosphere. Commercial ZSM-5 zeolite has been used as catalyst in liquid phase contact. In every case, high HHV gases and liquids which can be useful as fuels or source of chemicals are obtained. A solid fraction composed of the inorganic material contained in the raw materials and some char formed in the pyrolysis process is also obtained. The zeolite has shown to be very effective to produce liquids with great aromatics content and C3-C4 fraction rich gases, even though the raw material was mainly composed of polyolefins. The characteristics of the pyrolysis products as well as the effect of the catalyst vary depending on the composition of the raw material. When paper rich samples are pyrolysed, ZSM-5 zeolite increases water production and reduces CO and CO{sub 2} generation. If stepwise pyrolysis is applied to such sample, the aqueous liquid phase can be separated from the organic liquid fraction in a first low temperature step.

  8. Small clusters of II-VI materials: ZniOi, i=1-9

    NASA Astrophysics Data System (ADS)

    Matxain, Jon M.; Fowler, Joseph E.; Ugalde, Jesus M.

    2000-11-01

    Improvements in the characterization of II-VI compound-based solar cells, and the recent experimental characterization of small clusters and nanoparticles, make the study of small II-VI clusters very interesting. In this work, the ground states of small ZniOi clusters are studied, where i=1-9. Ringlike structures have been found to be the global minima for clusters as large as i=7, and three-dimensional spheroid structures for larger ones, where i=8 and 9. This is due to the stability of obtuse O-Zn-O angles in the first case, and to the stability gained from higher coordination in the second case. Three-dimensional structures may be envisioned as being built from Zn2O2 and Zn3O3 rings, as was the case for ZnS three-dimensional global minima and other ZnO calculations. Calculated natural orbital charges become larger as the cluster size increases, showing a tendency toward bulk charges.

  9. Small clusters of II-VI materials: ZniSi, i=1-9

    NASA Astrophysics Data System (ADS)

    Matxain, Jon M.; Fowler, Joseph E.; Ugalde, Jesus M.

    2000-05-01

    The improvements in the characterization of II-VI compound-based solar cells and the recent experimental characterization of small clusters and nanoparticles make the study of small II-VI clusters very interesting. In this work, the ground states of small ZniSi clusters are studied, i=1-9. Ringlike structures have been found to be the global minima in the case of the smaller studied clusters, i.e., i=1-5, and three-dimensional spheroid structures for larger ones, i=6-9. This is due to the stability of obtuse S-Zn-S angles in the first case, and to the stability gained from higher coordination in the second case. The three-dimensional structures may be envisioned as being built from Zn2S2 and Zn3S3 rings, the last ring being the building block of the zinc-sulfide crystal structures, both zinc blende and wurtzite. As cluster size increases, the geometry of the Zn3S3 rings is closer to the one of bulk. Moreover, this structural tendency produces trends to bulklike properties in other properties such as cohesive energy and atomic charges.

  10. Platinum(II) Metallomesogens: New External-Stimuli-Responsive Photoluminescence Materials.

    PubMed

    Cuerva, Cristián; Campo, José A; Cano, Mercedes; Lodeiro, Carlos

    2016-07-11

    New dicatenar isoquinoline-functionalized pyrazoles, [Hpz(R(n,n)iq) ] (R(n,n)=C6 H3 (OCn H2n+1 )2 ; n=4, 6, 8, 10, 12, 14, 16, 18), have been strategically designed and synthesized to induce mesomorphic and luminescence properties into the corresponding bis(isoquinolinylpyrazolate)platinum(II) complexes [Pt(pz(R(n,n)iq) )2 ]. Thermal studies reveal that all platinum(II) compounds exhibit columnar mesophases over an exceptionally wide temperature range, above 300 °C in most cases. The photophysical behavior was also investigated in solution and in the solid state. As a consequence of the formation of Pt⋅⋅⋅Pt interactions, the weak greenish emission of the platinum derivatives turns bright orange in the mesophase. Additionally, the complexes are sensitive to a great variety of external inputs, such as temperature, mechanical grinding, pressure, solvents, and vapors. On this basis, they are used as dopant agents of a polyvinylpyrrolidone or poly(methyl methacrylate) polymer matrix to achieve stimuli-responsive thin films.

  11. Economic evaluation of closure CAP barrier materials Volume I and Volume II

    SciTech Connect

    Serrato, M.G.; Bhutani, J.S.; Mead, S.M.

    1993-09-01

    This study prepared by the Site Geotechnical Services (SGS) and Environmental Restoration (ER) departments of the WSRC evaluates a generic closure cover system for a hazardous waste site, using 10 different surface areas, ranging from 0.1 acre to 80 acres, and 12 barrier materials. This study presents a revision to the previous study (Rev. 0) published in June 1993, under the same title. The objective of this study was to revise the previous study by incorporating four additional site sizes into the evaluation process and identifying the most cost-effective barrier material for a given closure cover system at the SRS.

  12. Gas adsorption and structural diversity in a family of Cu(II) pyridyl-isophthalate metal-organic framework materials

    NASA Astrophysics Data System (ADS)

    Gould, Jamie A.; Athwal, Harprit Singh; Blake, Alexander J.; Lewis, William; Hubberstey, Peter; Champness, Neil R.; Schröder, Martin

    2017-01-01

    A family of Cu(II)-based metal-organic frameworks (MOFs) has been synthesized using three pyridyl-isophthalate ligands, H2L1 (4'-(pyridin-4-yl)biphenyl-3,5-dicarboxylic acid), H2L2 (4''-(pyridin-4-yl)-1,1':4',1''-terphenyl-3,5-dicarboxylic acid) and H2L3 (5-[4-(pyridin-4-yl)naphthalen-1-yl]benzene-1,3-dicarboxylic acid). Although in each case the pyridyl-isophthalate ligands adopt the same pseudo-octahedral [Cu2(O2CR)4N2] paddlewheel coordination modes, the resulting frameworks are structurally diverse, particularly in the case of the complex of Cu(II) with H2L3, which leads to three distinct supramolecular isomers, each derived from Kagomé and square nets. In contrast to [Cu(L2)] and the isomers of [Cu(L3)], [Cu(L1)] exhibits permanent porosity. Thus, the gas adsorption properties of [Cu(L1)] were investigated with N2, CO2 and H2, and the material exhibits an isosteric heat of adsorption competitive with leading MOF sorbents for CO2. [Cu(L1)] displays high H2 adsorption, with the density in the pores approaching that of liquid H2. This article is part of the themed issue 'Coordination polymers and metal-organic frameworks: materials by design'.

  13. Fracture strength and elastic modulus as a function of porosity for hydroxyapatite and other brittle materials, Part II

    SciTech Connect

    Fan, Xiaofeng; Case, Eldon D; Ren, Fei; Shu, Yutian; Baumann, Melissa

    2012-01-01

    Part I of this paper discussed the Weibull modulus m, versus porosity P behavior of brittle materials, including HA. While the Weibull modulus m deals with the scatter in fracture strength data, this paper (Part II) focuses on two additional key mechanical properties of porous materials, namely the average fracture strength f , and Young s modulus E, for P in the interval from P zero to P PG (the porosity of the unfired compacts). The f versus P data for HA from this study and the literature data for alumina, yttria stabilized zirconia (YSZ) and silicon nitride are describedwell by functions of , where = 1 P/PG = the degree of densification. A similar function of applies to the E versus P behavior of HA from this study and data from the literature for alumina, titanium and YSZ. All of the data analyzed in this study (Part II) are based on partially and fully sintered powder compacts (excluding green powder compacts), thus the f / 0 versus and E /E0 versus relationships may apply only to such specimens.

  14. Gas adsorption and structural diversity in a family of Cu(II) pyridyl-isophthalate metal-organic framework materials.

    PubMed

    Gould, Jamie A; Athwal, Harprit Singh; Blake, Alexander J; Lewis, William; Hubberstey, Peter; Champness, Neil R; Schröder, Martin

    2017-01-13

    A family of Cu(II)-based metal-organic frameworks (MOFs) has been synthesized using three pyridyl-isophthalate ligands, H2L(1) (4'-(pyridin-4-yl)biphenyl-3,5-dicarboxylic acid), H2L(2) (4''-(pyridin-4-yl)-1,1':4',1''-terphenyl-3,5-dicarboxylic acid) and H2L(3) (5-[4-(pyridin-4-yl)naphthalen-1-yl]benzene-1,3-dicarboxylic acid). Although in each case the pyridyl-isophthalate ligands adopt the same pseudo-octahedral [Cu2(O2CR)4N2] paddlewheel coordination modes, the resulting frameworks are structurally diverse, particularly in the case of the complex of Cu(II) with H2L(3), which leads to three distinct supramolecular isomers, each derived from Kagomé and square nets. In contrast to [Cu(L(2))] and the isomers of [Cu(L(3))], [Cu(L(1))] exhibits permanent porosity. Thus, the gas adsorption properties of [Cu(L(1))] were investigated with N2, CO2 and H2, and the material exhibits an isosteric heat of adsorption competitive with leading MOF sorbents for CO2 [Cu(L(1))] displays high H2 adsorption, with the density in the pores approaching that of liquid H2This article is part of the themed issue 'Coordination polymers and metal-organic frameworks: materials by design'. © 2016 The Author(s).

  15. Development of a Laser Induced Fluorescence (LIF) system on the Plasma Material Interaction System (PLAMIS-II) device

    NASA Astrophysics Data System (ADS)

    Kang, I. J.; Lee, K. Y.; Lee, K. I.; Choi, Y.-S.; Cho, S. G.; Bae, M. K.; Lee, D.-H.; Hong, S. H.; Lho, T.; Chung, K.-S.

    2015-12-01

    A laser induced fluorescence (LIF) system has been developed for the plasma material interaction system (PLAMIS-II) device, which is equipped with a unique plasma gun composed of a LaB6 cathode and two anodes with electromagnets to generate a focused dense plasma. PLAMIS-II simulates the interactions of plasma with different materials and is to be used for the test of plasma facing components of fusion devices. The LIF system is composed of a seed laser with Littmann/Metcalf cavity and a master oscillator power amplifier to pump 3d4F7/2 metastable argon ion to 4p4D5/2 level at the wavelength of 668.61 nm, which has the following input parameters: laser power = 20 mW, line width < 100 kHz, and a mode-hop free tuning range > 70 GHz. For in-situ measurement of laser wavelength, the wavelength spectrum of an iodine cell was measured by a photo-transistor during LIF measurement. To measure argon ion temperature (Ti) and drift velocity (vd) in PLAMIS-II, the fluorescence light with the wavelength of 442.72 nm, emitted from 4p4D5/2 level to 4s4P3/2 level and passing through 1 nm band-width filter, was collected by the photomultiplier tube combined with a lock-in amplifier and a chopper with frequency of 3 kHz. Initial data of Ti and vd were analysed in terms of gas flow rate and applied power.

  16. Modeling the combined effect of pH and temperature on the heat resistance of Bacillus stearothermophilus spores heated in a multicomponent food extract.

    PubMed

    Tejedor, W; Rodrigo, M; Martínez, A

    2001-10-01

    The combined effect of pH and temperature on the heat resistance of Bacillus stearothermophilus spores heated in an extract of complex food was studied. The results showed that, in general, reducing the pH reduced the heat resistance of the spores. Similarly, the value for the D parameter in the nonacidified extract was between 30 and 70% lower than the one obtained with double-distilled water. This result once again shows the importance of the substrate in inactivation studies of microorganisms. The experimental data were used to carry out a comparison of two predictive mathematical models of inactivation, one based on a multiparametric regression obtained in this study and the other obtained from the bibliography and based on a linear-Bigelow equation. Both models predict reasonably well, although the multiparametric model presented a slightly better accuracy factor (1.11) than the one obtained with the linear-Bigelow equation (1.13).

  17. Masonry Specialist I & II, 3-19. Military Curriculum Materials for Vocational and Technical Education.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    These military-developed curriculum materials consist of a course description, plan of instruction, study guides, and workbooks for use in training masonry specialists. Covered in the course blocks are an introduction to masonry and rigid concrete structures. The introduction to masonry, course block I, deals with safety, mathematics and…

  18. Aviation Machinist's Mate Phase II, 2-6. Military Curriculum Materials for Vocational and Technical Education.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    These teacher and student materials, the second section of a two phase secondary/postsecondary-level course on aviation machinists, make up one of a number of military-developed curriculum packages selected for adaptation to vocational instruction and curriculum development in a civilian setting. The purpose of the course is to train students to…

  19. Construction Mechanic Part II, 8-6. Military Curriculum Materials for Vocational and Technical Education.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This course, adapted from military curriculum materials for use in vocational and technical education, is the second of a two-course series that teaches students to maintain and repair automotive and construction equipment using either gasoline or diesel engines. It covers basic chassis and power train troubleshooting, diagnosis, and adjustment…

  20. Newspaper Bargains: Food I and II. Teacher's Guide [and] Student Materials.

    ERIC Educational Resources Information Center

    Kenne, Linda

    The document contains student materials and teacher's guides for two units in which students analyze grocery advertisements in newspapers. The units are appropriate for language arts and mathematics classes in grades 4-6. Objectives for Unit I include discriminating between an advertisement and a news article, identifying foods for sale in ads,…

  1. Supplemental Driver Safety Program Development Volume II--Pilot and Field Test Module Materials. Final Report.

    ERIC Educational Resources Information Center

    McPherson, Kenard; Weidman, James R.

    This volume contains materials to supplement existing driver education programming offered by high schools to youthful (16- to 18-year old) drivers. Section I contains three drinking/driving modules: an information-only module, a self-image module, and a three-unit peer intervention module. An instructor's guide provided for each module includes…

  2. Performance Oriented Packaging Testing of Container, CNU-125/E for Packing Group II Solid Hazardous Material.

    DTIC Science & Technology

    1991-08-21

    Shipping and Storage Container Type: 1A2 Container P/N or NSN: 8E 8140 - 01 -006-0503 Specification Number: Material: 30003-2603387 Steel Cylinder Gross...report is interim, final, etc. If DOD - See DoDD 5230.24, "Distribution applicable, enter inclusive report dates (e.g. 10 Seenon Technial Jun 87 - 30 Jun

  3. Bilingual Education Instructional and Training Materials. Field Test Results and Final Phase II Report.

    ERIC Educational Resources Information Center

    Mahone, Alicia

    The report describes a federally funded project for the development of an innovative approach to bilingual curriculum and instruction and inservice teacher training. A needs assessment and research process resulted in development and field testing of a set of bilingual Spanish-English instructional materials for limited-English-speaking urban…

  4. Electronic Principles II, 7-6. Military Curriculum Materials for Vocational and Technical Education.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This second of 10 blocks of student and teacher materials for a secondary/postsecondary level course in electronic principles comprises one of a number of military-developed curriculum packages selected for adaptation to vocational instruction and curriculum development in a civilian setting. A prerequisite is the previous block. This block on AC…

  5. Buffalo Skins, Corn, Wampum, and Money. Part I and II. Teacher's Guide [and] Student Materials.

    ERIC Educational Resources Information Center

    Anderson, Judith K.

    This unit, designed for elementary school social studies classes, contains student materials and teacher's guide for exploring different means of exchanging goods and services. The unit is divided into two parts and designed around a learning center approach. In Part I the student uses pictures, games, and activity sheets to distinguish between…

  6. Biological induced corrosion of materials II: new test methods and experiences from MIR station.

    PubMed

    Klintworth, R; Reher, H J; Viktorov, A N; Bohle, D

    1999-01-01

    During previous long-term manned missions, more than 100 species of microorganisms have been identified on surfaces of materials (bacteria and fungi). Among them were potentially pathogenic ones (saprophytes) which are capable of active growth on artificial substrates, as well as technophilic bacteria and fungi causing damages (destruction and degradation) to various materials (metals and polymers), resulting in failures and disruptions in the functioning of equipment and hardware. Aboard a space vehicle some microclimatic parameters are optimal for microorganism growth: the atmospheric fluid condensate with its specific composition, chemical and/or anthropogenic contaminants (human metabolic products, etc.) all are stimulating factors for the development of bacteria and mould fungi on materials of the interior and equipment of an orbital station during its operational phase(s). Especially Russian long-term missions (SALYUT, MIR) [correction of SALJUT] have demonstrated that uncontrolled interactions of microorganisms with materials will ultimately lead to the appearance of technological and medical risks, significantly influencing safety and reliability characteristics of individual as well as whole systems and/or subsystems. For a first conclusion, it could be summarized, that countermeasures and anti-strategies focusing on Microbial Contamination Management (MCM) for the International Space Station (ISS, next long-term manned mission) at least require a new materials test approach. Our respective concept includes a combined aging/biocorrosion test sequence. It is represented here, as well as current status of MCM program, e.g. continuous monitoring (microbiological analyses), long-term disinfection, frequent cleaning methods, mathematical modeling of ISS, etc.

  7. Numerical simulations of granular dynamics II: Particle dynamics in a shaken granular material

    NASA Astrophysics Data System (ADS)

    Murdoch, Naomi; Michel, Patrick; Richardson, Derek C.; Nordstrom, Kerstin; Berardi, Christian R.; Green, Simon F.; Losert, Wolfgang

    2012-05-01

    Surfaces of planets and small bodies of our Solar System are often covered by a layer of granular material that can range from a fine regolith to a gravel-like structure of varying depths. Therefore, the dynamics of granular materials are involved in many events occurring during planetary and small-body evolution thus contributing to their geological properties. We demonstrate that the new adaptation of the parallel N-body hard-sphere code pkdgrav has the capability to model accurately the key features of the collective motion of bidisperse granular materials in a dense regime as a result of shaking. As a stringent test of the numerical code we investigate the complex collective ordering and motion of granular material by direct comparison with laboratory experiments. We demonstrate that, as experimentally observed, the scale of the collective motion increases with increasing small-particle additive concentration. We then extend our investigations to assess how self-gravity and external gravity affect collective motion. In our reduced-gravity simulations both the gravitational conditions and the frequency of the vibrations roughly match the conditions on asteroids subjected to seismic shaking, though real regolith is likely to be much more heterogeneous and less ordered than in our idealised simulations. We also show that collective motion can occur in a granular material under a wide range of inter-particle gravity conditions and in the absence of an external gravitational field. These investigations demonstrate the great interest of being able to simulate conditions that are to relevant planetary science yet unreachable by Earth-based laboratory experiments.

  8. Syntheses, crystal structures, thermal stabilities and luminescence of six M(II)-hydroxyphosphonoacetate materials

    SciTech Connect

    Fu, Ruibiao; Hu, Shengmin; Wu, Xintao

    2011-04-15

    Hydrothermal reactions of Zn{sup II}, Ba{sup II} or Co{sup II} ion with 2-hydroxyphosphonoacetic acid (H{sub 3}L) afforded six metal phosphonates, namely, [Zn{sub 5}(O{sub 3}PCH(OH)CO{sub 2}){sub 4}(C{sub 6}H{sub 9}N{sub 2}){sub 2}] (1), [(C{sub 4}H{sub 12}N{sub 2})Zn{sub 5}(O{sub 3}PCH(OH)CO{sub 2}){sub 4}(H{sub 2}O){sub 2}] (2), [(C{sub 3}H{sub 12}N{sub 2}){sub 0.5}Zn{sub 5}(HO{sub 3}PCH(OH)CO{sub 2})(O{sub 3}PCH(OH)CO{sub 2}){sub 3}(H{sub 2}O){sub 2}].0.75H{sub 2}O (3), [BaZn{sub 2}(O{sub 3}P CH(OH)CO{sub 2}){sub 2}] (4), [Ba(HO{sub 3}PCH(OH)CO{sub 2})] (5) and [(NH{sub 4}){sub 2}Co{sub 7}(HO{sub 3}PCH(OH) CO{sub 2}){sub 6}(HPO{sub 4}){sub 2}(H{sub 2}O){sub 6}].4H{sub 2}O (6). In 1, zinc tetrahedra ([ZnO{sub 4}]) and octahedra ([ZnO{sub 5}N], [ZnO{sub 6}]) are bridged by 2-hydroxyphosphonoacetate with penta- and hexadendate modes into a hybrid layer, which is further pillared by the 3-picolylamines to form a 3D structure through Zn-N bonds and hydrogen bondings. Both 2 and 3 are 3D framework encapsulating piperazine and 1,2-propanediamine cations, respectively. In solids 4-6, the cross-linkages of [ZnO{sub 4}], [BaO{sub 10}] and [CoO{sub 6}] polyhedral with 2-hydroxyphosphonoacetate form 3D frameworks. Solids 3 and 4 behave thermally stable up to 250 and 300 {sup o}C under air atmosphere, respectively. It is interesting that the peak emission of solid 3 displays a 10 nm red-shift after simple heat-treatment. -- Graphical abstract: Six new metal phosphonates exhibit layered or 3D frameworks based on 2-hydroxyphosphonoacetate with five new coordination modes. Display Omitted Research highlights: {yields} Metal phosphonates are layered or 3D frameworks. {yields} Metal phosphonates are stable up to 250-300 {sup o}C under air atmosphere. {yields} 2-Hydroxyphosphonoacetate displays five new coordination modes.

  9. Solute Transport Proteins and the Outer Membrane Protein NmpC Contribute to Heat Resistance of Escherichia coli AW1.7▿

    PubMed Central

    Ruan, Lifang; Pleitner, Aaron; Gänzle, Michael G.; McMullen, Lynn M.

    2011-01-01

    This study aimed to elucidate determinants of heat resistance in Escherichia coli by comparing the composition of membrane lipids, as well as gene expression, in heat-resistant E. coli AW1.7 and heat-sensitive E. coli GGG10 with or without heat shock. The survival of E. coli AW1.7 at late exponential phase was 100-fold higher than that of E. coli GGG10 after incubation at 60°C for 15 min. The cytoplasmic membrane of E. coli AW1.7 contained a higher proportion of saturated and cyclopropane fatty acids than that of E. coli GGG10. Microarray hybridization of cDNA libraries obtained from exponentially growing or heat-shocked cultures was performed to compare gene expression in these two strains. Expression of selected genes from different functional groups was quantified by quantitative PCR. DnaK and 30S and 50S ribosomal subunits were overexpressed in E. coli GGG10 relative to E. coli AW1.7 upon heat shock at 50°C, indicating improved ribosome stability. The outer membrane porin NmpC and several transport proteins were overexpressed in exponentially growing E. coli AW1.7. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of membrane properties confirmed that NmpC is present in the outer membrane of E. coli AW1.7 but not in that of E. coli GGG10. Expression of NmpC in E. coli GGG10 increased survival at 60°C 50- to 1,000-fold. In conclusion, the outer membrane porin NmpC contributes to heat resistance in E. coli AW1.7, but the heat resistance of this strain is dependent on additional factors, which likely include the composition of membrane lipids, as well as solute transport proteins. PMID:21398480

  10. Heat resistance and salt hypersensitivity in Lactococcus lactis due to spontaneous mutation of llmg_1816 (gdpP) induced by high-temperature growth.

    PubMed

    Smith, William M; Pham, Thi Huong; Lei, Lin; Dou, Junchao; Soomro, Aijaz H; Beatson, Scott A; Dykes, Gary A; Turner, Mark S

    2012-11-01

    During construction of several gene deletion mutants in Lactococcus lactis MG1363 which involved a high-temperature (37.5°C) incubation step, additional spontaneous mutations were observed which resulted in stable heat resistance and in some cases salt-hypersensitive phenotypes. Whole-genome sequencing of one strain which was both heat resistant and salt hypersensitive, followed by PCR and sequencing of four other mutants which shared these phenotypes, revealed independent mutations in llmg_1816 in all cases. This gene encodes a membrane-bound stress signaling protein of the GdpP family, members of which exhibit cyclic dimeric AMP (c-di-AMP)-specific phosphodiesterase activity. Mutations were predicted to lead to single amino acid substitutions or protein truncations. An independent llmg_1816 mutant (Δ1816), created using a suicide vector, also displayed heat resistance and salt hypersensitivity phenotypes which could be restored to wild-type levels following plasmid excision. L. lactis Δ1816 also displayed improved growth in response to sublethal concentrations of penicillin G. High-temperature incubation of a wild-type industrial L. lactis strain also resulted in spontaneous mutation of llmg_1816 and heat-resistant and salt-hypersensitive phenotypes, suggesting that this is not a strain-specific phenomenon and that it is independent of a plasmid integration event. Acidification of milk by the llmg_1816-altered strain was inhibited by lower salt concentrations than the parent strain. This study demonstrates that spontaneous mutations can occur during high-temperature growth of L. lactis and that inactivation of llmg_1816 leads to temperature resistance and salt hypersensitivity.

  11. Stress-Induced Evolution of Heat Resistance and Resuscitation Speed in Escherichia coli O157:H7 ATCC 43888.

    PubMed

    Gayán, Elisa; Cambré, Alexander; Michiels, Chris W; Aertsen, Abram

    2016-11-15

    The development of resistance in foodborne pathogens to food preservation techniques is an issue of increasing concern, especially in minimally processed foods where safety relies on hurdle technology. In this context, mild heat can be used in combination with so-called nonthermal processes, such as high hydrostatic pressure (HHP), at lower individual intensities to better retain the quality of the food. However, mild stresses may increase the risk of (cross-)resistance development in the surviving population, which in turn might compromise food safety. In this investigation, we examined the evolution of Escherichia coli O157:H7 strain ATCC 43888 after recurrent exposure to progressively intensifying mild heat shocks (from 54.0°C to 60.0°C in 0.5°C increments) with intermittent resuscitation and growth of survivors. As such, mutant strains were obtained after 10 cycles of selection with ca. 10(6)-fold higher heat resistance than that for the parental strain at 58.0°C, although this resistance did not extend to temperatures exceeding 60.0°C. Moreover, these mutant strains typically displayed cross-resistance against HHP shock and displayed signs of enhanced RpoS and RpoH activity. Interestingly, additional cycles of selection maintaining the intensity of the heat shock constant (58.5°C) selected for mutant strains in which resuscitation speed, rather than resistance, appeared to be increased. Therefore, it seems that resistance and resuscitation speed are rapidly evolvable traits in E. coli ATCC 43888 that can compromise food safety.

  12. Modeling the thermal inactivation kinetics of heat-resistant Salmonella Enteritidis and Oranienburg in 10 percent salted liquid egg yolk.

    PubMed

    Gurtler, Joshua B; Marks, Harry M; Jones, Deana R; Bailey, Rebecca R; Bauer, Nathan E

    2011-06-01

    There is no suitable model for predicting thermal inactivation kinetics of Salmonella spp. for many types of liquid egg products, including salted liquid egg yolk, for use in updating U.S. Department of Agriculture (USDA) pasteurization guidelines. This is because, in part, of the variations in Salmonella strains and the changes in the processing of liquid egg products over the past 40 years. The objectives of the present study were to determine the thermal inactivation kinetics and to create a general thermal inactivation kinetics model that can be used for estimating log reductions of salmonellae in 10% salted liquid egg yolk for temperatures between 62.2 and 69°C. This model can be used by processors to help ensure adequate pasteurization. This was accomplished by studying the inactivation kinetics of a three-strain composite of heat-resistant Salmonella serovars Enteritidis and Oranienburg, inoculated into commercially processed 10% salted liquid egg yolk. The survival curves were convex, with asymptotic D-values. From these curves, a general model was developed to predict log reductions for given times at specified temperatures. For example, at a temperature of 67.3°C (153.1°F) for 3.5 min, our model predicts a 5-log reduction would be obtained, whereas with the current USDA minimum required pasteurization regimen (63.33°C [146°F] for 3.5 min), our model predicts that a reduction of only 2.7 log would be obtained. The results of this study provide information that can be used by processors to aid in producing safe, pasteurized egg yolk products, and for satisfying USDA pasteurization performance standards and developing industry guidance.

  13. Formation Mechanism of Type IV Failure in High Cr Ferritic Heat-Resistant Steel-Welded Joint

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Tsukamoto, S.; Shirane, T.; Abe, F.

    2013-10-01

    The mechanism of type IV failure has been investigated by using a conventional 9Cr ferritic heat-resistant steel Gr.92. In order to clarify the main cause of type IV failure, different heat treatments were performed on the base metal in order to change the prior austenite grain (PAG) size and precipitate distribution after applying the heat-affected zone (HAZ) simulated thermal cycle at the peak temperature of around A c3 ( A c3 HAZ thermal cycle) and postweld heat treatment (PWHT). The microstructural evolution during the A c3 HAZ thermal cycle and PWHT was investigated by means of scanning electron microscope (SEM), electron backscatter diffraction (EBSD), electron probe microanalysis (EPMA), and transmission electron microscope (TEM). It was found that M23C6 carbides were scarcely precipitated at the newly formed fine PAG, block, and lath boundaries in A c3 HAZ-simulated Gr.92, because the carbide forming elements such as Cr and C were segregated at the former PAG and block boundaries of the base metal. On the other hand, if all the boundaries were covered by sufficient M23C6 carbides by homogenization of the alloying elements prior to applying the HAZ thermal cycle, the creep strength was much improved even if the fine PAG was formed. From these results, it is concluded that fine-grained microstructure cannot account for the occurrence of type IV failure, and it only has a small effect during long-term creep. The most important factor is the precipitate formation behavior at various boundaries. Without sufficient boundary strengthening by precipitates, the microstructure of A c3 HAZ undergoes severe changes even during PWHT and causes premature failure during creep.

  14. Molecular characterization of heat shock protein 70 (HSP 70) promoter in Japanese flounder (Paralichthys olivaceus), and the association of Pohsp70 SNPs with heat-resistant trait.

    PubMed

    Qi, Jie; Liu, Xudong; Liu, Jinxiang; Yu, Haiyang; Wang, Wenji; Wang, Zhigang; Zhang, Quanqi

    2014-08-01

    Ambient temperature is one of the major abiotic environmental factors determining the main parameters of fish vital activity. HSP70 plays an essential role in heat response. In this investigation, the promoter and structure of Paralichthys olivaceus hsp70 (Pohsp70) gene was cloned and predicted. 2558 bp upstream regulatory region of Pohsp70 was annotated with four potential promoter elements and four putative binding sites of transcription factors heat shock elements (HSE, nGAAn) in the upstream of the transcription start site. In addition, one intron with 454 bp in the 5'-noncoding region was found. Quantitative Real Time PCR analysis indicated that the transcript level of Pohsp70 was raised markedly after 1 h by heat shocked. Furthermore, 25 SNPs were identified in Pohsp70 by resequencing, seven of which was associated with heat resistance. In addition, two of the seven SNPs, namely SNP14 and SNP16, were observed in strong linkage disequilibrium. The haplotype with association analysis showed TAGGAG haplotype was more represented in heat susceptible group while (DEL/T) GAATA haplotype was more frequent in heat resistant group. The heat resistant SNPs and haplotype could be candidate markers potentially serving for selective breeding programs of Japanese flounder aimed at improving anti-stress and production.

  15. Seasonal influence on heat-resistant proteolytic capacity of Pseudomonas lundensis and Pseudomonas fragi, predominant milk spoilers isolated from Belgian raw milk samples.

    PubMed

    Marchand, Sophie; Heylen, Kim; Messens, Winy; Coudijzer, Katleen; De Vos, Paul; Dewettinck, Koen; Herman, Lieve; De Block, Jan; Heyndrickx, Marc

    2009-02-01

    Psychrotolerant bacteria and their heat-resistant proteases play a major role in the spoilage of UHT-processed dairy products. Summer and winter raw milk samples were screened for the presence of such bacteria. One hundred and three proteolytic psychrotolerant bacteria were isolated, characterized by API tests, rep-PCR fingerprint analysis and evaluated for heat-resistant protease production. Twenty-nine strains (representing 79% of the complete collection) were further identified by 16S rRNA gene sequencing, rpoB gene sequencing and DNA-DNA hybridizations. A seasonal inter- and intra-species influence on milk spoilage capacity (e.g. growth rate and/or protease production) was demonstrated. Moreover, this polyphasic approach led to the identification of Pseudomonas fragi and Pseudomonas lundensis (representing 53% of all isolates) as predominant producers of heat-resistant proteases in raw milk. The role of Pseudomonas fluorescens, historically reported as important milk spoiler, could not unequivocally be established. The use of more reliable identification techniques and further revision of the taxonomy of P. fluorescens will probably result in a different perspective on its role in the milk spoilage issue.

  16. Effect of Carbon Content on Microstructure and Mechanical Properties of 9 to 12 pct Cr Ferritic/Martensitic Heat-Resistant Steels

    NASA Astrophysics Data System (ADS)

    Yin, Feng-Shi; Tian, Li-Qian; Xue, Bing; Jiang, Xue-Bo; Zhou, Li

    2012-07-01

    Two heats of 9 to 12 pct Cr ferritic/martensitic heat-resistant steels were prepared. One has an ultralow carbon content of 0.01 wt pct, whereas another heat has a normal carbon content of 0.09 wt pct. The effect of carbon content on microstructure and mechanical properties of 9 to 12 pct Cr ferritic/martensitic heat-resistant steels was studied. The results show that the ultralow-carbon steel contains bimodal, nanosized MX precipitates with high density in the matrix but few M23C6 carbide particles in the normalized-and-tempered state. The smaller nanosized MX precipitates have two kinds of typical morphology: One is cubic and another is rectangular. The cubic MX precipitate contains Nb, Ti, and V, whereas the rectangular one only contains Nb and V. The normal carbon steel has abundant M23C6 carbide particles along the grain and lath boundaries and much less density of nanosized MX precipitates after the same heat treatments. After long-term aging at 923 K (650 °C) for 10,000 hours, the stress rupture properties of the ultralow carbon content steel degrades more significantly. The strength degradation mechanism of the 9 to 12 pct Cr ferritic/martensitic heat-resistant steels is discussed in this article.

  17. Effect of the medium characteristics and the heating and cooling rates on the nonisothermal heat resistance of Bacillus sporothermodurans IC4 spores.

    PubMed

    Esteban, María-Dolores; Huertas, Juan-Pablo; Fernández, Pablo S; Palop, Alfredo

    2013-05-01

    In recent years, highly thermo-resistant mesophilic spore-forming bacteria belonging to the species Bacillus sporothermodurans have caused non-sterility problems in industrial sterilization processes. The aim of this research was to evaluate the effect of the heating medium characteristics (pH and buffer/food) on the thermal inactivation of B. sporothermodurans spores when exposed to isothermal and non-isothermal heating and cooling treatments and the suitability of non-linear Weibull and Geeraaerd models to predict the survivors of these thermal treatments. Thermal treatments were carried out in pH 3, 5 and 7 McIlvaine buffer and in a courgette soup. Isothermal survival curves showed shoulders that were accurately characterized by means of both models. A clear effect of the pH of the heating medium was observed, decreasing the D120 value from pH 7 to pH 3 buffer down to one third. Differences in heat resistance were similar, regardless of the model used and were kept at all temperatures tested. The heat resistance in courgette soup was similar to that shown in pH 7 buffer. When the heat resistance values obtained under isothermal conditions were used to predict the survival in the non-isothermical experiments, the predictions estimated the experimental data quite accurately, both with Weibull and Geeraerd models.

  18. A finite element method for the thermochemical decomposition of polymeric materials. II - Carbon phenolic composites

    NASA Technical Reports Server (NTRS)

    Sullivan, R. M.; Salamon, N. J.

    1992-01-01

    A previously developed formulation for modeling the thermomechanical behavior of chemically decomposing, polymeric materials is verified by simulating the response of carbon phenolic specimens during two high temperature tests: restrained thermal growth and free thermal expansion. Plane strain and plane stress models are used to simulate the specimen response, respectively. In addition, the influence of the poroelasticity constants upon the specimen response is examined through a series of parametric studies.

  19. Perspiration Poisoning of Protective Clothing Materials. Part II. Mathematical Model for a Complex Adsorption Bed

    DTIC Science & Technology

    1974-06-01

    long-time objective of the grant that funded this research is to remedy this "poisoning" problem; therefore, the modeling work considersthe different...chni-al ewt MATERIALS. "THEMATICAL MODEL FORE"ORMING RPoRT E A COMPLEX ADSORF 1ION .ED-.--L 7- --AU .LO - -/- 8. CONTRACT QR GRATNUMBER(.) J...AREA & WORK 14qITUMBERS Department of Chemical Engineering North Carolina State University % 62105A Raleigh, North Carolina 27607 - TI62105AH8 102107 I

  20. Reference materials (RMs) for analysis of the human factor II (prothrombin) gene G20210A mutation.

    PubMed

    Klein, Christoph L; Márki-Zay, János; Corbisier, Philippe; Gancberg, David; Cooper, Susan; Gemmati, Donato; Halbmayer, Walter-Michael; Kitchen, Steve; Melegh, Béla; Neumaier, Michael; Oldenburg, Johannes; Leibundgut, Elisabeth Oppliger; Reitsma, Pieter H; Rieger, Sandra; Schimmel, Heinz G; Spannagl, Michael; Tordai, Attilia; Tosetto, Alberto; Visvikis, Sophie; Zadro, Renata; Mannhalter, Christine

    2005-01-01

    The Scientific Committee of Molecular Biology Techniques (C-MBT) in Clinical Chemistry of the IFCC has initiated a joint project in co-operation with the European Commission, Joint Research Centre, Institute of Reference Materials and Measurements to develop and produce plasmid-type reference materials (RMs) for the analysis of the human prothrombin gene G20210A mutation. Although DNA tests have a high impact on clinical decision-making and the number of tests performed in diagnostic laboratories is high, issues of quality and quality assurance exist, and currently only a few RMs for clinical genetic testing are available. A gene fragment chosen was produced that spans all primer annealing sites published to date. Both the wild-type and mutant alleles of this gene fragment were cloned into a pUC18 plasmid and two plasmid RMs were produced. In addition, a mixture of both plasmids was produced to mimic the heterozygous genotype. The present study describes the performance of these reference materials in a commutability study, in which they were tested by nine different methods in 13 expert laboratories. This series of plasmid RMs are, to the best of our knowledge, the first plasmid-type clinical genetic RMs introduced worldwide.

  1. Seminar on the Acquisition of Latin American Library Materials (13th, Lawrence, Kansas, June 20-22, 1968). Final Report and Working Papers. Vol. II.

    ERIC Educational Resources Information Center

    Jordan, Alma; Rovira, Carmen

    The eight working papers used as documentation for the Thirteenth Seminar are included in volume II. They are: (1) "Progress Report on the Seminars on the Acquisition of Latin American Library Materials, 1968;" (2) "Significant Acquisitions of Latin American Material by U.S. Libraries, 1967/68;" (3) "A Report of…

  2. Seminar on the Acquisition of Latin American Library Materials (13th, Lawrence, Kansas, June 20-22, 1968). Final Report and Working Papers. Vol. II.

    ERIC Educational Resources Information Center

    Jordan, Alma; Rovira, Carmen

    The eight working papers used as documentation for the Thirteenth Seminar are included in volume II. They are: (1) "Progress Report on the Seminars on the Acquisition of Latin American Library Materials, 1968;" (2) "Significant Acquisitions of Latin American Material by U.S. Libraries, 1967/68;" (3) "A Report of…

  3. Theoretical Design and Material Growth of Type-II Antimonide-based Superlattices for Infrared Detection and Imaging

    NASA Astrophysics Data System (ADS)

    Nguyen, Binh-Minh

    The goal of this PhD thesis is to investigate quantum properties of the superlattice system, design appropriate device architectures and experimentally fabricate infrared detectors which can outperform currently existing devices. In parallel, efforts in material growth using molecular beam epitaxy (MBE) have resulted in higher material quality and vastly improved growth conditions of III-V compounds as compared to previous work. Superlattices as thick as 15mum were realized without growth defects or dislocations, narrow X-ray diffraction peaks and small surface roughness. Many ternary and quaternary layers such as InAsSb, AlAsSb, GaAlAsSb were routinely used in new design architectures to enhance the electrical performance of the devices. Advances in theoretical calculations and material growth have allowed this work to continue with comprehensive studies of photodetector device architectures. Fundamental parameters affecting the performance of infrared detectors were investigated. We have experimentally pointed out the difference in the collection of photocurrent generated in the n-type and p-type regions. By forcing the device's active region to have an appropriate p-doped concentration, and by assuring long diffusion carrier lengths with high material quality, the quantum efficiency of Type-II superlattice photodiodes have been demonstrated in excess 50% in front side illumination configuration and 75% in back side illumination configuration. In an attempt to optimize the electrical performance, basic mechanisms of the dark current have been thoroughly analyzed. By intentionally doping the active region, the diffusion and generation-recombination currents were reduced until they were overwhelmed by the tunneling current. The device performance was then further enhanced due to the suppression of the tunneling current using the hetero-design of the M-structure superlattice. This optimization scheme can be repeated iteratively to lower all bulk-components of the

  4. Collision of a vortex ring on granular material. Part II. Erosion of the granular layer

    NASA Astrophysics Data System (ADS)

    Yoshida, Junya; Masuda, Naoya; Ito, Boku; Furuya, Takayoshi; Sano, Osamu

    2012-02-01

    In our previous paper (part I), an experimental result was presented on the normal impact of a vortex ring on the granular layer (glass beads of diameter 0.10 mm), which was placed at a specified distance from the outlet of the vortex ring generator. The Reynolds number of the vortex ring ranged from 1000 to 6000, whereas the traveling distance ranged from 2 to 13 times of the diameter of the vortex ring generator nozzle. In part I, the deformation of the vortex ring impacting on the granular layer and the development of the secondary vortex ring were focused. In this paper (part II), the erosion of the granular surface by the vortex ring is described. Various patterns were found depending on the Reynolds number of the vortex ring and the traveling distance. Two patterns, one (grooves) which has radial striations from the central depressed region to the outer edge of the rim and the other (dimples) which is characterized by isolated small depressions around the outer edge of the rim, are examined in detail. The formation processes of these patterns are elucidated in terms of the deformation of the vortex ring.

  5. Tailoring of ZnO with selected group-II elements for LED materials

    NASA Astrophysics Data System (ADS)

    Saleem, Murtaza; Manzoor, Adnan; Zaffar, Mohammed; Hussain, Syed Zajif; Anwar, M. Sabieh

    2016-06-01

    The semiconductor ZnO is a promising candidate for its applications in light-emitting diodes. In this study ZnO nanostructures tailored with selected group-II elements were synthesized using sol-gel-based fuel-agent-assistive chemical technique. Structural studies from X-ray diffraction analysis revealed the presence of wurtzite hexagonal crystal structure in all compositions confirming the stability of the Mg-doped structure while indicating presence of some traces of un-reacted and oxides of Sr and Ba in other compositions. Lattice parameters, crystallite size, lattice strain, density, and cell volume were extracted from X-ray diffraction data. Morphology and elemental composition analysis showed exact correlation with structural arrangements. The size of particles was also observed with dynamic light-scattering measurements. Absorbance and electrical transport studies were performed using UV-Vis spectrophotometry and four-probe measurements, respectively; the former was used to estimate the band gap of nanostructures. Energy-dispersive X-ray analysis was employed for confirming the substitution of Mg, Sr, and Ba atoms at Zn and O sites. Band gap values show strong dependence upon the tailored ZnO compositions.

  6. Structural Dimensions, Fabrication, Materials, and Operational History for Types I and II Waste Tanks

    SciTech Connect

    Wiersma, B.J.

    2000-08-16

    Radioactive waste is confined in 48 underground storage tanks at the Savannah River Site. The waste will eventually be processed and transferred to other site facilities for stabilization. Based on waste removal and processing schedules, many of the tanks, including those with flaws and/or defects, will be required to be in service for another 15 to 20 years. Until the waste is removed from storage, transferred, and processed, the materials and structures of the tanks must maintain a confinement function by providing a leak-tight barrier to the environment and by maintaining acceptable structural stability during design basis event which include loading from both normal service and abnormal conditions.

  7. Ceramic Thermal Protection Materials - How Far Can We Go? (Part II)

    NASA Astrophysics Data System (ADS)

    Hilfer, G.

    2002-01-01

    A space vehicle re-entering the earth's atmosphere is exposed to severe environmental conditions. In particular, certain surface areas of the vehicle such as the stagnation point area or exposed control surfaces have to withstand extraordinary thermal and oxidative loads. These loads that have to be taken by a thermal protection system (TPS) are driven mainly by the geometry of the vehicle, its mass and its re-entry path. As a consequence, small vehicles like the X-38 demonstrator of a re-usable crew return vehicle (CRV) need TPS components capable of withstanding temperatures of 1800°C accompanied by severe aerodynamic and chemical loads. Currently, the only promising materials having the potential of re-usability in such an environment are Si-based ceramics and related derivatives such as C-C/SiC. These materials have an extended oxidation regime leading to the formation of an oxidation-inhibiting SiO2-layer. Nevertheless, a number of parameters may turn this so-called passive oxidation mode into a different oxidation mode which can be characterized by the release of gaseous SiO. This is the so-called active oxidation mode which induces massive degradation of the material. Based on a long-term experimental and theoretical investigation performed on the constituents of SiC and its most important derivatives and oxidation products, a mechanism was proposed describing the relevant parameters which govern the transition from passive to active oxidation of SiC in a re-entry type environment. The crucial reaction process related to this transition was found to be the interaction of SiO and SiO2 with atomic and molecular oxygen, i.e. In a previous publication this mechanism was derived by a thorough study of a large number of related elementary reaction steps and the analysis of experimental findings [1]. In the course of the investigation, however, many other results have been obtained which could not be published within the frame of the above publication. Therefore

  8. Advanced Composite Substrate Development of CD-Based-II-VI Materials for IR Applications

    DTIC Science & Technology

    2004-12-01

    set of these quarternary layers. Finally, both CdTe and CdSe layers were grown to establish baseline parameters and properties. Structural...increasing to unity. Since the CdTe binary compound is a zincblende crystal while the CdSe binary compound is a wurtzite crystal, it is reasonable...to expect a phase change in crystal structure at some Se composition within the CdSexTe1-x material system as we go from CdTe (x = 0) to CdSe (x = 1

  9. Effect of PVC and iron materials on Mn(II) deposition in drinking water distribution systems.

    PubMed

    Cerrato, José M; Reyes, Lourdes P; Alvarado, Carmen N; Dietrich, Andrea M

    2006-08-01

    Polyvinyl chloride (PVC) and iron pipe materials differentially impacted manganese deposition within a drinking water distribution system that experiences black water problems because it receives soluble manganese from a surface water reservoir that undergoes biogeochemical cycling of manganese. The water quality study was conducted in a section of the distribution system of Tegucigalpa, Honduras and evaluated the influence of iron and PVC pipe materials on the concentrations of soluble and particulate iron and manganese, and determined the composition of scales formed on PVC and iron pipes. As expected, total Fe concentrations were highest in water from iron pipes. Water samples obtained from PVC pipes showed higher total Mn concentrations and more black color than that obtained from iron pipes. Scanning electron microscopy demonstrated that manganese was incorporated into the iron tubercles and thus not readily dislodged from the pipes by water flow. The PVC pipes contained a thin surface scale consisting of white and brown layers of different chemical composition; the brown layer was in contact with the water and contained 6% manganese by weight. Mn composed a greater percentage by weight of the PVC scale than the iron pipe scale; the PVC scale was easily dislodged by flowing water. This research demonstrates that interactions between water and the infrastructure used for its supply affect the quality of the final drinking water.

  10. FLASH SPECTROSCOPY: EMISSION LINES FROM THE IONIZED CIRCUMSTELLAR MATERIAL AROUND <10-DAY-OLD TYPE II SUPERNOVAE

    SciTech Connect

    Khazov, D.; Yaron, O.; Gal-Yam, A.; Manulis, I.; Rubin, A.; Ofek, E. O.; Horesh, A.; Kulkarni, S. R.; Kasliwal, M. M.; Cao, Y.; Perley, D.; Arcavi, I.; Howell, D. A.; Sollerman, J.; Sullivan, M.; Filippenko, A. V.; Nugent, P. E.; Cenko, S. B.; Silverman, J. M.; Ebeling, H.; and others

    2016-02-10

    Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra (≤10 days after the explosion), owing to recombination of the CSM ionized by the shock-breakout flash. From such spectra (“flash spectroscopy”), we can measure various physical properties of the CSM, as well as the mass-loss rate of the progenitor during the year prior to its explosion. Searching through the Palomar Transient Factory (PTF and iPTF) SN spectroscopy databases from 2009 through 2014, we found 12 SNe II showing flash-ionized (FI) signatures in their first spectra. All are younger than 10 days. These events constitute 14% of all 84 SNe in our sample having a spectrum within 10 days from explosion, and 18% of SNe II observed at ages <5 days, thereby setting lower limits on the fraction of FI events. We classified as “blue/featureless” (BF) those events having a first spectrum that is similar to that of a blackbody, without any emission or absorption signatures. It is possible that some BF events had FI signatures at an earlier phase than observed, or that they lack dense CSM around the progenitor. Within 2 days after explosion, 8 out of 11 SNe in our sample are either BF events or show FI signatures. Interestingly, we found that 19 out of 21 SNe brighter than an absolute magnitude M{sub R} = −18.2 belong to the FI or BF groups, and that all FI events peaked above M{sub R} = −17.6 mag, significantly brighter than average SNe II.

  11. Flash Spectroscopy: Emission Lines From the Ionized Circumstellar Material Around 10-Day-Old Type II Supernovae

    NASA Technical Reports Server (NTRS)

    Khazov, D.; Yaron, O.; Gal-Yam, A.; Manulis, I.; Rubin, A.; Kulkarni, S. R.; Arcavi, I.; Kasliwal, M. M.; Ofek, E. O.; Cao, Y.; hide

    2016-01-01

    Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra (< or =10 days after the explosion), owing to recombination of the CSM ionized by the shock-breakout flash. From such spectra ("flash spectroscopy"), we can measure various physical properties of the CSM, as well as the mass-loss rate of the progenitor during the year prior to its explosion. Searching through the Palomar Transient Factory (PTF and iPTF) SN spectroscopy databases from 2009 through 2014, we found 12 SNe II showing flash-ionized (FI) signatures in their first spectra. All are younger than 10 days. These events constitute 14% of all 84 SNe in our sample having a spectrum within 10 days from explosion, and 18% of SNe II observed at ages <5 days, thereby setting lower limits on the fraction of FI events. We classified as "blue/featureless" (BF) those events having a first spectrum that is similar to that of a blackbody, without any emission or absorption signatures. It is possible that some BF events had FI signatures at an earlier phase than observed, or that they lack dense CSM around the progenitor. Within 2 days after explosion, 8 out of 11 SNe in our sample are either BF events or show FI signatures. Interestingly, we found that 19 out of 21 SNe brighter than an absolute magnitude M(sub R) = -18.2 belong to the FI or BF groups, and that all FI events peaked above M(sub R) = -17.6 mag, significantly brighter than average SNe II.

  12. Flash Spectroscopy: Emission Lines from the Ionized Circumstellar Material Around <10-Day-Old Type II Supernovae

    SciTech Connect

    Khazov, Daniel; Yaron, O.; Gal-Yam, A.; Manulis, I.; Rubin, A.; Kulkarni, S. R.; Arcavi, I.; Kasliwal, M. M.; Ofek, E. O.; Cao, Y.; Perley, D.; Sollerman, J.; Horesh, A.; Sullivan, M.; Filippenko, A. V.; Nugent, P. E.; Howell, D. A.; Cenko, S. B.; Silverman, J. M.; Ebeling, H.; Taddia, F.; Johansson, J.; Laher, R. R.; Surace, J.; Rebbapragada, U. D.; Wozniak, Przemyslaw R.; Matheson, T.

    2016-02-02

    Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra (≤10 days after the explosion), owing to recombination of the CSM ionized by the shock-breakout flash. From such spectra ("flash spectroscopy"), we can measure various physical properties of the CSM, as well as the mass-loss rate of the progenitor during the year prior to its explosion. In this paper, by searching through the Palomar Transient Factory (PTF and iPTF) SN spectroscopy databases from 2009 through 2014, we found 12 SNe II showing flash-ionized (FI) signatures in their first spectra. All are younger than 10 days. These events constitute 14% of all 84 SNe in our sample having a spectrum within 10 days from explosion, and 18% of SNe II observed at ages <5 days, thereby setting lower limits on the fraction of FI events. We classified as "blue/featureless" (BF) those events having a first spectrum that is similar to that of a blackbody, without any emission or absorption signatures. It is possible that some BF events had FI signatures at an earlier phase than observed, or that they lack dense CSM around the progenitor. Within 2 days after explosion, 8 out of 11 SNe in our sample are either BF events or show FI signatures. Finally and interestingly, we found that 19 out of 21 SNe brighter than an absolute magnitude MR = -18.2 belong to the FI or BF groups, and that all FI events peaked above MR = -17.6 mag, significantly brighter than average SNe II.

  13. Flash Spectroscopy: Emission Lines from the Ionized Circumstellar Material Around <10-Day-Old Type II Supernovae

    DOE PAGES

    Khazov, Daniel; Yaron, O.; Gal-Yam, A.; ...

    2016-02-02

    Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra (≤10 days after the explosion), owing to recombination of the CSM ionized by the shock-breakout flash. From such spectra ("flash spectroscopy"), we can measure various physical properties of the CSM, as well as the mass-loss rate of the progenitor during the year prior to its explosion. In this paper, by searching through the Palomar Transient Factory (PTF and iPTF) SN spectroscopy databases from 2009 through 2014, we found 12 SNe II showing flash-ionized (FI) signatures in their first spectra. All are younger thanmore » 10 days. These events constitute 14% of all 84 SNe in our sample having a spectrum within 10 days from explosion, and 18% of SNe II observed at ages <5 days, thereby setting lower limits on the fraction of FI events. We classified as "blue/featureless" (BF) those events having a first spectrum that is similar to that of a blackbody, without any emission or absorption signatures. It is possible that some BF events had FI signatures at an earlier phase than observed, or that they lack dense CSM around the progenitor. Within 2 days after explosion, 8 out of 11 SNe in our sample are either BF events or show FI signatures. Finally and interestingly, we found that 19 out of 21 SNe brighter than an absolute magnitude MR = -18.2 belong to the FI or BF groups, and that all FI events peaked above MR = -17.6 mag, significantly brighter than average SNe II.« less

  14. Three-Dimensional Metal-Organic Framework as Super Heat-Resistant Explosive: Potassium 4-(5-Amino-3-Nitro-1H-1,2,4-Triazol-1-Yl)-3,5-Dinitropyrazole.

    PubMed

    Li, Chuan; Zhang, Man; Chen, Qishan; Li, Yingying; Gao, Huiqi; Fu, Wei; Zhou, Zhiming

    2017-01-31

    A new super heat-resistant explosive, potassium 4-(5-amino-3-nitro-1H-1,2,4-triazol-1-yl)-3,5-dinitropyrazole (KCPT, 1), featuring a three-dimensional (3D) energetic metal-organic framework (MOF) was synthesized and fully characterized. The new 3D MOF was found to be extremely heat-resistant, having a high decomposition temperature of 323 °C. In addition, KCPT exhibits the best calculated detonation performance (vD =8457 m s(-1) , p=32.5 GPa) among the reported super heat-resistant explosives or energetic potassium salts while retaining a suitable impact sensitivity of 7.5 J, which makes it one of the most promising heat-resistant explosives.

  15. New textile composite materials development, production, application

    NASA Technical Reports Server (NTRS)

    Mikhailov, Petr Y.

    1993-01-01

    New textile composite materials development, production, and application are discussed. Topics covered include: super-high-strength, super-high-modulus fibers, filaments, and materials manufactured on their basis; heat-resistant and nonflammable fibers, filaments, and textile fabrics; fibers and textile fabrics based on fluorocarbon poylmers; antifriction textile fabrics based on polyfen filaments; development of new types of textile combines and composite materials; and carbon filament-based fabrics.

  16. Stress-Induced Evolution of Heat Resistance and Resuscitation Speed in Escherichia coli O157:H7 ATCC 43888

    PubMed Central

    Gayán, Elisa; Cambré, Alexander; Michiels, Chris W.

    2016-01-01

    ABSTRACT The development of resistance in foodborne pathogens to food preservation techniques is an issue of increasing concern, especially in minimally processed foods where safety relies on hurdle technology. In this context, mild heat can be used in combination with so-called nonthermal processes, such as high hydrostatic pressure (HHP), at lower individual intensities to better retain the quality of the food. However, mild stresses may increase the risk of (cross-)resistance development in the surviving population, which in turn might compromise food safety. In this investigation, we examined the evolution of Escherichia coli O157:H7 strain ATCC 43888 after recurrent exposure to progressively intensifying mild heat shocks (from 54.0°C to 60.0°C in 0.5°C increments) with intermittent resuscitation and growth of survivors. As such, mutant strains were obtained after 10 cycles of selection with ca. 106-fold higher heat resistance than that for the parental strain at 58.0°C, although this resistance did not extend to temperatures exceeding 60.0°C. Moreover, these mutant strains typically displayed cross-resistance against HHP shock and displayed signs of enhanced RpoS and RpoH activity. Interestingly, additional cycles of selection maintaining the intensity of the heat shock constant (58.5°C) selected for mutant strains in which resuscitation speed, rather than resistance, appeared to be increased. Therefore, it seems that resistance and resuscitation speed are rapidly evolvable traits in E. coli ATCC 43888 that can compromise food safety. IMPORTANCE In this investigation, we demonstrated that Escherichia coli O157:H7 ATCC 43888 rapidly acquires resistance to mild heat exposure, with this resistance yielding cross-protection to high hydrostatic pressure treatment. In addition, mutants of E. coli ATCC 43888 in which resuscitation speed, rather than resistance, appeared to be improved were selected. As such, both resistance and resuscitation speed seem to be

  17. Numerical study of one-dimensional compression of granular materials. II. Elastic moduli, stresses, and microstructure

    NASA Astrophysics Data System (ADS)

    Khalili, Mohamed Hassan; Roux, Jean-Noël; Pereira, Jean-Michel; Brisard, Sébastien; Bornert, Michel

    2017-03-01

    The elastic moduli of a transversely isotropic model granular material, made of slightly polydisperse elastic-frictional spherical beads, in equilibrium along a one-dimensional (oedometric) compression path, as described in the companion paper [M. H. Khalili et al., Phys. Rev. E 95, 032907 (2017)], 10.1103/PhysRevE.95.032907, are investigated by numerical simulations. The relations of the five independent moduli to stresses, density, coordination number, fabric and force anisotropies are studied for different internal material states along the oedometric loading path. It is observed that elastic moduli, as in isotropic packs, are primarily determined by the coordination number, with anomalously small shear moduli in poorly coordinated systems, whatever their density. Such states also exhibit faster increasing moduli in compression, and larger off-diagonal moduli and Poisson ratios. Anisotropy affects the longitudinal moduli C11 in the axial direction and C22 in the transverse directions, and the shear modulus in the transverse plane C44, more than the shear modulus in a plane containing the axial direction C55. The results are compared to available experiments on anisotropic bead packs, revealing, despite likely differences in internal states, a very similar range of stiffness level (linked to coordination), and semiquantitative agreement as regards the influence of anisotropy. Effective medium theory (the Voigt approach) provides quite inaccurate predictions of the moduli. It also significantly underestimates ratios C11/C22 (varying between 1 and 2.2) and C55/C44 (varying from 1 to 1.6), which characterize elastic anisotropy, except in relatively weakly anisotropic states. The bulk modulus for isotropic compression and the compliance corresponding to stress increments proportional to the previous stress values are the only elastic coefficients to be correctly estimated by available predictive relations. We discuss the influences of fabric and force anisotropies

  18. Behavior of particulate materials during iron fertilization experiments in the Western Subarctic Pacific (SEEDS and SEEDS II)

    NASA Astrophysics Data System (ADS)

    Aramaki, Takafumi; Nojiri, Yukihiro; Imai, Keiri

    2009-12-01

    During two mesoscale iron-enrichment studies in the northwestern subarctic Pacific (SEEDS in 2001 summer and SEEDS II in 2004 summer), particulate materials from the iron-induced phytoplankton bloom in the upper water column were monitored to analyze the export processes beneath the upper mixed layer, mainly with drifting sediment traps. We could not observe the total downward export process of the high accumulation of particulate organic carbon from the mixed layer induced by the large diatom bloom of SEEDS [e.g., Tsuda, A., Takeda, S., Saito, H., Nishioka, J., Nojiri, Y., Kudo, I., Kiyosawa, H., Shiomoto, A., Imai, K., Ono, T., Shimamoto, A., Tsumune, D., Yoshimura, T., Aono, T., Hinuma, A., Kinugasa, M., Suzuki, K., Sohrin, Y., Noiri, Y., Tani, H., Deguchi, Y., Tsurushima, N., Ogawa, H., Fukami, K., Kuma, K., Saino, T., 2003. A mesoscale iron enrichment in the western subarctic Pacific induces large centric diatom bloom. Science 300, 958-961] because the 2-week observation period was too short to examine the decline phase of the bloom. In contrast, in SEEDS II, the particulate organic carbon and particulate organic nitrogen were accumulated 123 and 23 mmol m -2, respectively, in the mixed layer until day-15 (days from iron-enrichment), and then ca. 90% were removed from the mixed layer by day-25. The sediment traps at 40 m depth between day-15 and day-25 accounted for at least more than 35% of these particles. There was no large variation in chemical composition in settling particles above 100 m depth throughout the experimental periods both in SEEDS and SEEDS II. The content of biogenic opal remained more than 50% of all settling particles during SEEDS, while the content of biogenic calcium carbonate was relatively high, with a low biogenic opal content of consistently less than 30% during SEEDS II. These results suggest that high standing stock of seed population of diatoms before the iron fertilization, indicated by low C/Si ratio of particulate matter, is an

  19. ZERODUR for stressed mirror polishing II: improved modeling of the material behavior

    NASA Astrophysics Data System (ADS)

    Jedamzik, Ralf; Kunisch, Clemens; Westerhoff, Thomas; Müller, Ulrich; Daniel, Jay

    2012-09-01

    In the preceding part I of this paper stressed mirror polishing was stated as one of the processes assumed for the polishing of non-axisymmetric mirror blanks like those for the two ELT projects (the ESO E-ELT and the TMT). For this process it is important to have a precise knowledge of the elastic behavior of the glass ceramic mirror substrate materials. In reality glasses and glass ceramics do not react instantaneously to stresses at room temperature. This effect is called "delayed elasticity". It was shown that the delayed elasticity effect of ZERODUR is small in size (less than approximately 1% of the applied deformation) and fully reversible in time. A mathematical model on the relaxation of shear modulus and bulk modulus of ZERODUR has been introduced to predict the delayed elasticity at room temperature and different load cases. This second paper is focusing on an updated model approach with the target to improve the model prediction accuracy. The model results will be compared to measurements of the effect on a 1.5 m E-ELT mirror blank at L-3 Communications, Tinsley.

  20. Intercalation compounds of layered materials for drug delivery use. II. Diclofenac sodium.

    PubMed

    Suzuki, N; Nakamura, Y; Watanabe, Y; Kanzaki, Y

    2001-08-01

    Intercalation compounds of ternary layered inorganic materials, synthetic mica (Na-TSM), with diclofenac sodium (DFS) and its drug release characteristics were investigated. Hygroscopic DFS was selected as a model drug to verify the anti-humidity and anti-oxidation of the intercalation compounds. Na-TSM powder was first mixed with the reduced-type phosphatidylcholine (H-PC) solution of chloroform or ethanol. DFS was then mixed with these solutions and heated at 37 degrees C to prepare the ternary Na-TSM/H-PC/DFS compound. A remarkable phenomenon was observed in the drug release study. The net amount of DFS from the DFS powder decreased apparently after 20 min arising from the decomposition of DFS in acidic medium. On the other hand, the net amount of the released DFS from the intercalation compound was invariant. Thermal analyses study indicated that DFS powder was hygroscopic and a significant endothermic peak was observed accompanied by a large weight loss due to the dehydration of adsorbed water from 40 to 90 degrees C. On the other hand, no significant dehydration reaction was observed in the intercalation compounds even in the sample stored under humid conditions. The present results indicated that the ternary intercalation compound was resistant to acid in addition to anti-humidity.

  1. Dynamically driven phase transformations in heterogeneous materials. II. Applications including damage

    NASA Astrophysics Data System (ADS)

    Plohr, JeeYeon N.; Clements, B. E.; Addessio, F. L.

    2006-12-01

    A model, developed for heterogeneous materials undergoing dynamically driven phase transformations in its constituents, has been extended to include the evolution of damage. Damage is described by two mechanisms: interfacial debonding between the constituents and brittle failure micro-crack growth within the constituents. The analysis is applied to silicon carbide-titanium (SiC-Ti) unidirectional metal matrix composites that undergo the following phenomena: Ti has a yield stress of approximately 0.5 GPa and above a pressure of about 2 GPa undergoes a solid-solid phase transformation. The inelastic work from plastic dissipation contributes to the temperature and pressure rise in the Ti. SiC behaves elastically below a critical stress, above which it is damaged by microcrack growth. Finally, under tensile loading, the interface between Ti and SiC debonds according to an interfacial decohesion law. Each process is first examined independently in order to understand how its characteristic behavior is manifested in the stress-strain response of the composite. The complex interplay between loading states, viscoplasticity, damage, and solid-solid phase transformations is then studied at both the micromechanics and macromechanics levels.

  2. Quality of dredged material in the river Seine basin (France). II. Micropollutants.

    PubMed

    Carpentier, S; Moilleron, R; Beltran, C; Hervé, D; Thévenot, D

    2002-11-01

    Dredging rivers is needed to ensure safe navigable waters, rivers and waterways. To anticipate the management of dredged materials in the case of the river Seine basin, the quality of the sediments in the river is checked every 3 years before dredging operations. The river Seine Basin is heavily submitted to pollution pressure from nearby industrial activities and urban expansion of Paris and its region. Here, the micropollutant content of the sediment sampled in 1996, 1999 and 2000 before dredging is discussed compared to regulatory standards. The results indicate that most of the sediment samples from the river Seine basin are lightly to moderately contaminated with organic and inorganic micropollutants (heavy metals, PAH, PCB), which makes the management after dredging easier. This pollution is strongly correlated with the organic matter content and to the fine fraction (<50 microm) of the sediment. These results can lead to other management options than the ones already used in the river Seine basin: (1) dumping of lightly to moderately polluted sediments in quarries; and (2) physical treatment (sieving, hydrocycloning) of contaminated sediments issued from 'hot spots'.

  3. Control of Bacillus licheniformis spores isolated from dairy materials in yogurt production.

    PubMed

    Tanaka, Takashi; Ito, Akiko; Kamikado, Hideaki

    2012-01-01

    To determine the effects of sporulation temperature and period on Bacillus licheniformis spore heat resistance, B. licheniformis strain No.25 spores were sporulated at 30, 37, 42, or 50°C for 11 d and at 50°C for 1.7, 4, 7, or 11 d. The heat resistance of B. licheniformis strain No.25 spores at 110°C increased with an increase in the sporulation temperature. Spores sporulated at 50°C were 1.4-fold more heat resistant than those sporulated at 30°C. Furthermore, the heat resistance of B. licheniformis strain No.25 spores at 110°C increased with an increase in the sporulation period. Spores sporulated for 11 d were 5.3-fold more heat resistant than those sporulated for 1.7 d. The heat resistance of B. licheniformis strain No.25 spores at 110°C increased with increases in the sporulation temperature and sporulation period. The results presented in this study can be applied to the pasteurization process to control B. licheniformis spores. Pasteurization at 110°C for about 60sec. is effective in controlling B. licheniformis spores isolated from dairy materials in yogurt production.

  4. High temperature range recuperator. Phase II. Prototype demonstration and material and analytical studies. Final report

    SciTech Connect

    1980-04-01

    A summary of the work performed to fully evaluate the commercial potential of a unique ceramic recuperator for use in recovering waste heat from high temperature furnace exhaust gases is presented. The recuperator concept being developed consists of a vertical cylindrical heat exchange column formed from modular sections. Within the column, the gasketed modules form two helical flow passages - one for high temperature exhaust gases and one for pre-heating combustion air. The column is operated in a counterflow mode, with the exhaust gas entering at the bottom and the combustion air entering at the top of the column. Activities included design and procurement of prototype recuperator modules, construction and testing of two prototype recuperator assemblies, exposure and mechanical properties testing of candidate materials, structural analysis of the modules, and assessment of the economic viability of the concept. The results of the project indicated that the proposed recuperator concept was feasible from a technical standpoint. Economic analysis based upon recuperator performance characteristics and module manufacturing costs defined during the program indicated that 3 to 10 years (depending upon pre-heat temperature) would be required to recover the capital cost of the system in combustion air preheat applications. At this stage in the development of the recuperator, many factors in the analysis had to be assumed. Significant changes in some of the assumptions could dramatically affect the economics. For example, utilizing $2.85 per mcf for the natural gas price (as opposed to $2.00 per mcf) could reduce the payback period by more than half in certain cases. In addition, future commercial application will depend upon ceramic component manufacturing technique advances and cost reduction.

  5. A novel cellulose-manganese oxide hybrid material by in situ soft chemical synthesis and its application for the removal of Pb(II) from water.

    PubMed

    Maliyekkal, Shihabudheen M; Lisha, Kinattukara P; Pradeep, T

    2010-09-15

    We report an in situ soft chemical synthesis of a novel hybrid material, cellulose-nanoscale-manganese oxide composite (C-NMOC), and its application for Pb(II) removal from aqueous solutions. For comparison, detailed Pb(II) adsorption studies were also performed with nanoscale-manganese oxide powder (NMO), prepared through a similar route. Various spectroscopic and microscopic techniques were used to characterize the as-synthesized materials. X-ray photoelectron spectroscopic (XPS) measurements confirmed the existence of Mn(IV) phase in NMO whereas C-NMOC showed largely the Mn(III) phase. The existence and uniform distribution of manganese oxide in cellulose fiber materials was confirmed by SEM and EDAX analyses. The adsorption studies reveal that the Pb(II) uptake onto C-NMOC is a fast process and >90% of the uptake occurred within the first 10 min contact time. The Sips isotherm predicted the equilibrium data well and the maximum Pb(II) uptake capacity of C-NMOC (4.64% Mn loading) was estimated to be 80.1 mg g(-1). The Pb(II) adsorption capacity of C-NMOC (per gram of Mn present) was several times higher than commercial manganese oxide (beta-MnO2) and at least twice larger than NMO. The experimental evidence reveals that physisorption plays a dominant role in Pb(II) adsorption by both NMO and C-NMOC.

  6. 11% efficiency solid-state dye-sensitized solar cells with copper(II/I) hole transport materials

    PubMed Central

    Cao, Yiming; Saygili, Yasemin; Ummadisingu, Amita; Teuscher, Joël; Luo, Jingshan; Pellet, Norman; Giordano, Fabrizio; Zakeeruddin, Shaik Mohammed; Moser, Jacques -E.; Freitag, Marina; Hagfeldt, Anders; Grätzel, Michael

    2017-01-01

    Solid-state dye-sensitized solar cells currently suffer from issues such as inadequate nanopore filling, low conductivity and crystallization of hole-transport materials infiltrated in the mesoscopic TiO2 scaffolds, leading to low performances. Here we report a record 11% stable solid-state dye-sensitized solar cell under standard air mass 1.5 global using a hole-transport material composed of a blend of [Cu (4,4′,6,6′-tetramethyl-2,2′-bipyridine)2](bis(trifluoromethylsulfonyl)imide)2 and [Cu (4,4′,6,6′-tetramethyl-2,2′-bipyridine)2](bis(trifluoromethylsulfonyl)imide). The amorphous Cu(II/I) conductors that conduct holes by rapid hopping infiltrated in a 6.5 μm-thick mesoscopic TiO2 scaffold are crucial for achieving such high efficiency. Using time-resolved laser photolysis, we determine the time constants for electron injection from the photoexcited sensitizers Y123 into the TiO2 and regeneration of the Y123 by Cu(I) to be 25 ps and 3.2 μs, respectively. Our work will foster the development of low-cost solid-state photovoltaic based on transition metal complexes as hole conductors. PMID:28598436

  7. Growth and characterization of Bis(L-threonine) copper (II) monohydrate single crystals: A semiorganic second order nonlinear optical material

    NASA Astrophysics Data System (ADS)

    Subhashini, R.; Sathya, D.; Sivashankar, V.; Latha Mageshwari, P. S.; Arjunan, S.

    2016-12-01

    Highly transparent solitary nonlinear semiorganic optical material Bis(L-threonine) copper (II) monohydrate [BLTCM], was synthesized by a conventional slow evaporation solution growth technique. The grown crystals were subjected to structural, optical, electrical, thermal, mechanical, SHG and Laser damage threshold studies. Single crystal XRD shows that the material crystallizes in monoclinic system with noncentrosymmetric space group P21. FT-IR and FT-RAMAN analyses confirm the various functional groups present in the grown crystal. The transparency range of BLTCM was determined by UV-vis-NIR studies and various optical constants such as extinction coefficient (K), refractive index, optical conductivity and electric susceptibility with real and imaginary parts of dielectric constant were calculated using the transmittance data which have applications in optoelectronic devices. Dielectric studies of the crystal were carried out at different frequencies and temperatures to analyze the electrical properties. TGA and DSC analyses were performed to study the thermal behaviour of the sample. The hardness stability of the grown specimen was investigated by Vickers microhardness test. The output intensity of second harmonic generation was confirmed using the Kurtz and Perry powder method. The laser induced surface damage threshold of the crystal was measured using Nd:YAG laser.

  8. 11% efficiency solid-state dye-sensitized solar cells with copper(II/I) hole transport materials

    NASA Astrophysics Data System (ADS)

    Cao, Yiming; Saygili, Yasemin; Ummadisingu, Amita; Teuscher, Joël; Luo, Jingshan; Pellet, Norman; Giordano, Fabrizio; Zakeeruddin, Shaik Mohammed; Moser, Jacques-E.; Freitag, Marina; Hagfeldt, Anders; Grätzel, Michael

    2017-06-01

    Solid-state dye-sensitized solar cells currently suffer from issues such as inadequate nanopore filling, low conductivity and crystallization of hole-transport materials infiltrated in the mesoscopic TiO2 scaffolds, leading to low performances. Here we report a record 11% stable solid-state dye-sensitized solar cell under standard air mass 1.5 global using a hole-transport material composed of a blend of [Cu (4,4',6,6'-tetramethyl-2,2'-bipyridine)2](bis(trifluoromethylsulfonyl)imide)2 and [Cu (4,4',6,6'-tetramethyl-2,2'-bipyridine)2](bis(trifluoromethylsulfonyl)imide). The amorphous Cu(II/I) conductors that conduct holes by rapid hopping infiltrated in a 6.5 μm-thick mesoscopic TiO2 scaffold are crucial for achieving such high efficiency. Using time-resolved laser photolysis, we determine the time constants for electron injection from the photoexcited sensitizers Y123 into the TiO2 and regeneration of the Y123 by Cu(I) to be 25 ps and 3.2 μs, respectively. Our work will foster the development of low-cost solid-state photovoltaic based on transition metal complexes as hole conductors.

  9. 11% efficiency solid-state dye-sensitized solar cells with copper(II/I) hole transport materials.

    PubMed

    Cao, Yiming; Saygili, Yasemin; Ummadisingu, Amita; Teuscher, Joël; Luo, Jingshan; Pellet, Norman; Giordano, Fabrizio; Zakeeruddin, Shaik Mohammed; Moser, Jacques-E; Freitag, Marina; Hagfeldt, Anders; Grätzel, Michael

    2017-06-09

    Solid-state dye-sensitized solar cells currently suffer from issues such as inadequate nanopore filling, low conductivity and crystallization of hole-transport materials infiltrated in the mesoscopic TiO2 scaffolds, leading to low performances. Here we report a record 11% stable solid-state dye-sensitized solar cell under standard air mass 1.5 global using a hole-transport material composed of a blend of [Cu (4,4',6,6'-tetramethyl-2,2'-bipyridine)2](bis(trifluoromethylsulfonyl)imide)2 and [Cu (4,4',6,6'-tetramethyl-2,2'-bipyridine)2](bis(trifluoromethylsulfonyl)imide). The amorphous Cu(II/I) conductors that conduct holes by rapid hopping infiltrated in a 6.5 μm-thick mesoscopic TiO2 scaffold are crucial for achieving such high efficiency. Using time-resolved laser photolysis, we determine the time constants for electron injection from the photoexcited sensitizers Y123 into the TiO2 and regeneration of the Y123 by Cu(I) to be 25 ps and 3.2 μs, respectively. Our work will foster the development of low-cost solid-state photovoltaic based on transition metal complexes as hole conductors.

  10. Restricted accessed material-copper(II) ion imprinted polymer solid phase extraction combined with inductively coupled plasma-optical emission spectrometry for the determination of free Cu(II) in urine and serum samples.

    PubMed

    Cui, Chao; He, Man; Chen, Beibei; Hu, Bin

    2013-11-15

    A novel restricted accessed material (RAM)-Cu(II) ion imprinted polymer (IIP) was synthesized by the surface imprinted-emulsion method, and possessed a high selectivity to Cu(II) and good macromolecules exclusion property. And a novel method of RAM-IIP packed microcolumn solid phase extraction (SPE) combined with inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed for the determination of trace free Cu(II) in human body fluids. Under the optimized conditions, the adsorption capacity of RAM-IIP for Cu(II) was 15.9 mg g(-1). With a preconcentration factor of 30, the limit of detection was 0.17 µg L(-1), and the relative standard deviation was 2.2% (n=7, c=1 µg L(-1)). The developed method was validated by the analysis of two Certified Reference Materials, and the determined values were in good agreement with the certified values. This method was also successfully applied for the direct analysis of free Cu(II) in human urine and serum samples. While the total Cu can be determined by the proposed method after microwave digestion. The concentrations of free Cu(II) were much lower than that of total Cu, indicating that Cu is mainly coordinated with macromolecules in these biological samples. From this point of view, the developed method exhibits application potential in speciation of free metal ions and metallic complex molecules in biological samples. © 2013 Elsevier B.V. All rights reserved.

  11. The World-Wide-Failure-Exercises-I and -II for UD Materials- Valuable Attempts to Validate Failure Theories on Basis of More or Less Applicable Test Data Materials

    NASA Astrophysics Data System (ADS)

    Cuntze, Ralf

    2014-06-01

    There was a lack of really validated 2D and 3D strength failure conditions (SFC) for unidirectional (UD) laminas. In the World-Wide-Failure-Exercises WWFE-I (2D stress states) and II (3D stress states), organized by QinetiQ (UK) in the past 20 years, it was extensively attempted to fill this gap. The author participated in both these exercises with a set of 'modal' failure conditions for the brittle behaving, transversely-isotropic UD lamina material composed of endless fibre-reinforced polymers. These conditions base on his so-called Failure Mode Concept (FMC). In the paper the provided, more or less applicable or even not reliable test data sets - provided for the Test Cases (TC) - are discussed with the aim of a better exploitation. There are no further data sets available. Therefore the interested designer must get sufficient knowledge about the quality of the data sets. With a better understanding the designer will be able to perform design verification with a remaining minimum amount of costly test work. To achieve this, the author presents his personal WWFE assessments, provides lessons learnt and draws conclusions.

  12. Performance Oriented Packaging Testing of Tank, Cartridge, 3 in/50, Mk 5 Mods 0, 1, 2 for Packing Group II Solid Hazardous Materials

    DTIC Science & Technology

    1993-01-01

    Mods 0 , 1, 2 for Packing Group II Solid Hazardous Materials 6. AUTHORIS) Karen McDonnell 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8...design, size, and weight, this test is considered representative of qualifica- tion testing for the Mk 5 Mods 0 , 2 3"/50 Cartridge Tanks as per the...PERFORMANCE ORIENTED PACKAGING TESTING OF TANK, CARTRIDGE, 3"/50, MK 5 MODS 0 , 1, 2 FOR PACKING GROUP II SOLID HAZARDOUS MATERIALS Author: Karen

  13. The Effect of Contrast Material on Radiation Dose at CT: Part II. A Systematic Evaluation across 58 Patient Models.

    PubMed

    Sahbaee, Pooyan; Abadi, Ehsan; Segars, W Paul; Marin, Daniele; Nelson, Rendon C; Samei, Ehsan

    2017-06-01

    Purpose To estimate the radiation dose as a result of contrast medium administration in a typical abdominal computed tomographic (CT) examination across a library of contrast material-enhanced computational patient models. Materials and Methods In part II of this study, first, the technique described in part I of this study was applied to enhance the extended cardiac-torso models with patient-specific iodine-time profiles reflecting the administration of contrast material. Second, the patient models were deployed to assess the patient-specific organ dose as a function of time in a typical abdominal CT examination using Monte Carlo simulation. In this hypothesis-generating study, organ dose refers to the total energy deposited in the unit mass of the tissue inclusive of iodine. Third, a study was performed as a strategy to anticipate the biologically relevant dose (absorbed dose to tissue) in highly perfused organs such as the liver and kidney. The time-varying organ-dose increment values relative to those for unenhanced CT examinations were reported. Results The results from the patient models subjected to the injection protocol indicated up to a total 53%, 30%, 35%, 54%, 27%, 18%, 17%, and 24% increase in radiation dose delivered to the heart, spleen, liver, kidneys, stomach, colon, small intestine, and pancreas, respectively. The biologically relevant dose increase with respect to the dose at an unenhanced CT examination was in the range of 0%-18% increase for the liver and 27% for the kidney across 58 patient models. Conclusion The administration of contrast medium increases the total radiation dose. However, radiation dose, while relevant to be included in estimating the risk associated with contrast-enhanced CT, may still not fully characterize the total biologic effects. Therefore, given the fact that many CT diagnostic decisions would be impossible without the use of iodine, this study suggests the need to consider the effect of iodinated contrast material

  14. Predictive model for the reduction of heat resistance of Listeria monocytogenes in ground beef by the combined effect of sodium chloride and apple polyphenols.

    PubMed

    Juneja, Vijay K; Altuntaş, Evrim Güneş; Ayhan, Kamuran; Hwang, Cheng-An; Sheen, Shiowshuh; Friedman, Mendel

    2013-06-03

    We investigated the combined effect of three internal temperatures (57.5, 60, and 62.5°C) and different concentrations (0 to 3.0 wt/wt.%) of sodium chloride (NaCl) and apple polyphenols (APP), individually and in combination, on the heat-resistance of a five-strain cocktail of Listeria monocytogenes in ground beef. A complete factorial design (3×4×4) was used to assess the effects and interactions of heating temperature, NaCl, and APP. All 48 combinations were tested twice, to yield 96 survival curves. Mathematical models were then used to quantitate the combined effect of these parameters on heat resistance of the pathogen. The theoretical analysis shows that compared with heat alone, the addition of NaCl enhanced and that of APP reduced the heat resistance of L. monocytogenes measured as D-values. By contrast, the protective effect of NaCl against thermal inactivation of the pathogen was reduced when both additives were present in combination, as evidenced by reduction of up to ~68% in D-values at 57.5°C; 65% at 60°C; and 25% at 62.5°C. The observed high antimicrobial activity of the combination of APP and low salt levels (e.g., 2.5% APP and 0.5% salt) suggests that commercial and home processors of meat could reduce the salt concentration by adding APP to the ground meat. The influence of the combined effect allows a reduction of the temperature of heat treatments as well as the salt content of the meat. Meat processors can use the predictive model to design processing times and temperatures that can protect against adverse effects of contaminated meat products. Additional benefits include reduced energy use in cooking, and the addition of antioxidative apple polyphenols may provide beneficial health affects to consumers.

  15. Explorations of new second-order nonlinear optical materials in the K(I)-M(II)-I(V)-O systems.

    PubMed

    Li, Pei-Xin; Hu, Chun-Li; Xu, Xiang; Wang, Rui-Yao; Sun, Chuan-Fu; Mao, Jiang-Gao

    2010-05-17

    Explorations of new second-order nonlinear optical (NLO) materials in the K(I)-M(II) -I(V)-O systems led to four novel mixed metal iodates, namely, K(2)M(IO(3))(4)(H(2)O)(2) (M = Mn, Co, Zn, Mg). The four compounds are isostructural and crystallize in space group I2 which is in the chiral and polar crystal class 2. Their structure features zero-dimensional {M(IO(3))(4)(H(2)O)(2)}(2-) anions that are separated by K(+) cations. The M(II) centers are ligated by two aqua ligands in trans fashion and four monodentate iodate anions. The K(+) cation is eight-coordinated by two iodate anions in bidentate chelating fashion and four other iodates in a unidentate fashion. Second harmonic generation (SHG) measurements indicate that K(2)Zn(IO(3))(4)(H(2)O)(2) and K(2)Mg(IO(3))(4)(H(2)O)(2) display moderate SHG responses that are approximately 2.3 and 1.4 times of KH(2)PO(4) (KDP), respectively, and they are also phase-matchable. The SHG response of K(2)Co(IO(3))(4)(H(2)O)(2) is much weaker (about 0.3 x KDP), and no obvious SHG signal was detected for K(2)Mn(IO(3))(4)(H(2)O)(2). Results of optical property calculations for the Zn and Mg phases revealed SHG responses of approximately 5.3 and 4.7 times of KDP, respectively, the order of Zn > Mg is in good agreement with the experiment data.

  16. Tetrahydrocannabinol (THC) alters synthesis and release of surfactant-related material in isolated fetal rabbit type II cells.

    PubMed

    Cherlet, T; Scott, J E

    2002-05-01

    to induce release of surfactant related material was also examined. In cells prelabelled with [3H]choline, THC induced release of [3H]DSPC in both cultured and freshly isolated fetal type II cells. These results suggest THC reduces formation of surfactant DSPC, probably through alterations in membrane dynamics. However, intracellular THC may actually increase formation of DSPC through an effect on the rate-limiting enzyme. THC also increases release of previously formed surfactant-related material.

  17. Stable optical oxygen sensing materials based on click-coupling of fluorinated platinum(II) and palladium(II) porphyrins—A convenient way to eliminate dye migration and leaching

    PubMed Central

    Koren, Klaus; Borisov, Sergey M.; Klimant, Ingo

    2012-01-01

    Nucleophilic substitution of the labile para-fluorine atoms of 2,3,4,5,6-pentafluorophenyl groups enables a click-based covalent linkage of an oxygen indicator (platinum(II) or palladium(II) 5,10,15,20-meso-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin) to the sensor matrix. Copolymers of styrene and pentafluorostyrene are chosen as polymeric materials. Depending on the reaction conditions either soluble sensor materials or cross-linked microparticles are obtained. Additionally, we prepared Ormosil-based sensors with linked indicator, which showed very high sensitivity toward oxygen. The effect of covalent coupling on sensor characteristics, stability and photophysical properties is studied. It is demonstrated that leaching and migration of the dye are eliminated in the new materials but excellent photophysical properties of the indicators are preserved. PMID:23576845

  18. Comparative study of the shear bond strength of various veneering materials on grade II commercially pure titanium.

    PubMed

    Lee, Eun-Young; Jun, Sul-Gi; Wright, Robert F; Park, Eun-Jin

    2015-02-01

    To compare the shear bond strength of various veneering materials to grade II commercially pure titanium (CP-Ti). Thirty specimens of CP-Ti disc with 9 mm diameter and 10 mm height were divided into three experimental groups. Each group was bonded to heat-polymerized acrylic resin (Lucitone 199), porcelain (Triceram), and indirect composite (Sinfony) with 7 mm diameter and 2 mm height. For the control group (n=10), Lucitone 199 were applied on type IV gold alloy castings. All samples were thermocycled for 5000 cycles in 5-55℃ water. The maximum shear bond strength (MPa) was measured with a Universal Testing Machine. After the shear bond strength test, the failure mode was assessed with an optic microscope and a scanning electron microscope. Statistical analysis was carried out with a Kruskal-Wallis Test and Mann-Whitney Test. The mean shear bond strength and standard deviations for experimental groups were as follows: Ti-Lucitone 199 (12.11 ± 4.44 MPa); Ti-Triceram (11.09 ± 1.66 MPa); Ti-Sinfony (4.32 ± 0.64 MPa). All of these experimental groups showed lower shear bond strength than the control group (16.14 ± 1.89 MPa). However, there was no statistically significant difference between the Ti-Lucitone 199 group and the control group, and the Ti-Lucitone 199 group and the Ti-Triceram group. Most of the failure patterns in all experimental groups were adhesive failures. The shear bond strength of veneering materials such as heat-polymerized acrylic resin, porcelain, and indirect composite to CP-Ti was compatible to that of heatpolymerized acrylic resin to cast gold alloy.

  19. Title II Elementary and Secondary Education Act (Public Law 89-10) as Amended. Annual Report, Fiscal Year 1972, School Library Resources, Textbooks, and Other Instructional Materials.

    ERIC Educational Resources Information Center

    Office of Education (DHEW), Washington, DC.

    Title II of the Elementary and Secondary Education Act (ESEA) of 1965 (Public Law 89-10) as amended, provides direct Federal assistance for the acquisition of school library resources, textbooks, and other instructional materials for the use of children and teachers in public and private elementary and secondary schools. Its purpose is to improve…

  20. A More Perfect Union: The American Government. Materials for Using American Issues Forum in the American History Classroom, Topic IV, Part II.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

    This booklet presents a set of secondary-level classroom strategies for examining American history in light of the issues identified by the American Issues Forum. Emphasis is on examination of the role and actions of the President of the United States. These materials, called modules, form Part II of the topic, "A More Perfect Union: The…

  1. Marginal leakage in class II-restorations after use of ceramic-inserts luted with different materials.

    PubMed

    Hahn, P; Schaller, H G; Müllner, U; Hellwig, E

    1998-08-01

    The efficiency of using prefabricated ceramic inlays to prevent microleakage has been discussed in different investigations. The purpose of this study was to evaluate the marginal microleakage of a new glass ceramic inlay system in combination with two different composite luting materials and one polyacid-modified composite, respectively. Standardized class II cavities (n = 60) were filled with (1) Empress inlays fixed with a highly viscous luting composite as a control group, and with glass ceramic inlays (Cerana) in combination with (2) a highly viscous luting composite, (3) a low-viscous luting composite and (4) a polyacid-modified composite, respectively. After thermocycling the marginal quality was analysed with scanning electron microscopy, and the dye penetration along the cavity walls was measured. The use of the Cerana inlays with a polyacid-modified composite resin did not reveal a good marginal adaptation. However, the combination of the Cerana and the Empress inlays with the highly viscous composite exhibited a comparable marginal fit. Within the limitations of an in vitro study it is concluded that the combination of the new glass ceramic inlays with a polyacid-modified composite cannot be recommended for clinical use.

  2. Structural and chemical disorder in semiconductors under pressure: Evidence in II-VI’s, role of photoactive defects, material predictions

    NASA Astrophysics Data System (ADS)

    Weinstein, Bernard A.; Lindberg, George P.; Gross, Nelson

    2017-05-01

    Hydrostatic pressure can sometimes generate structural and chemical disorder within crystals. We review pressure-Raman experiments on ZnSe, ZnTe, and CdSe showing evidence for these phenomena. In ZnSe and ZnTe Raman spectra recorded with low laser flux show only pre-transition structural disorder on approaching the lowest pressure transition, as is typical for first-order phase changes. Spectra recorded with higher laser flux (sub-band-gap) observe precipitation of anion nanocrystals. This behavior is absent in CdSe. A model is developed that considers the role of crystal defects. The defects promote plastic deformation assisted by photoexcitation of Jahn-Teller distortions. Nanocrystals can precipitate on dislocations in deformed regions under energetically favorable conditions. Model calculations based on theories for precipitation in metals account for the influence of pressure on the nanocrystal formation in ZnSe and ZnTe, and explain its absence in CdSe. Material maps are constructed to predict the tendencies for similar precipitation in III-V, II-VI, I-VII, and chalcopyrite crystals.

  3. Fiberglass material specification II

    SciTech Connect

    Frame, B.J.; Janke, C.J.

    1991-10-01

    This report describes the requirements for composite parts to be furnished to Martin Marietta Energy Systems, Inc. Topics discussed include: Part Fabrication Requirements, Scope, and Applicable Documents.

  4. Materialism.

    PubMed

    Melnyk, Andrew

    2012-05-01

    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website.

  5. Effects of N/C Ratio on Solidification Behaviors of Novel Nb-Bearing Austenitic Heat-Resistant Cast Steels for Exhaust Components of Gasoline Engines

    NASA Astrophysics Data System (ADS)

    Zhang, Yinhui; Li, Mei; Godlewski, Larry A.; Zindel, Jacob W.; Feng, Qiang

    2017-03-01

    In order to comply with more stringent environmental and fuel consumption regulations, novel Nb-bearing austenitic heat-resistant cast steels that withstand exhaust temperatures as high as 1,323 K (1,050 °C) is urgently demanded from automotive industries. In the current research, the solidification behavior of these alloys with variations of N/C ratio is investigated. Directional solidification methods were carried out to examine the microstructural development in mushy zones. Computational thermodynamic calculations under partial equilibrium conditions were performed to predict the solidification sequence of different phases. Microstructural characterization of the mushy zones indicates that N/C ratio significantly influenced the stability of γ-austenite and the precipitation temperature of NbC/Nb(C,N), thereby altering the solidification path, as well as the morphology and distribution of NbC/Nb(C,N) and γ-ferrite. The solidification sequence of different phases predicted by thermodynamic software agreed well with the experimental results, except the specific precipitation temperatures. The generated data and fundamental understanding will be helpful for the application of computational thermodynamic methods to predict the as-cast microstructure of Nb-bearing austenitic heat-resistant steels.

  6. Effects of N/C Ratio on Solidification Behaviors of Novel Nb-Bearing Austenitic Heat-Resistant Cast Steels for Exhaust Components of Gasoline Engines

    NASA Astrophysics Data System (ADS)

    Zhang, Yinhui; Li, Mei; Godlewski, Larry A.; Zindel, Jacob W.; Feng, Qiang

    2017-01-01

    In order to comply with more stringent environmental and fuel consumption regulations, novel Nb-bearing austenitic heat-resistant cast steels that withstand exhaust temperatures as high as 1,323 K (1,050 °C) is urgently demanded from automotive industries. In the current research, the solidification behavior of these alloys with variations of N/C ratio is investigated. Directional solidification methods were carried out to examine the microstructural development in mushy zones. Computational thermodynamic calculations under partial equilibrium conditions were performed to predict the solidification sequence of different phases. Microstructural characterization of the mushy zones indicates that N/C ratio significantly influenced the stability of γ-austenite and the precipitation temperature of NbC/Nb(C,N), thereby altering the solidification path, as well as the morphology and distribution of NbC/Nb(C,N) and γ-ferrite. The solidification sequence of different phases predicted by thermodynamic software agreed well with the experimental results, except the specific precipitation temperatures. The generated data and fundamental understanding will be helpful for the application of computational thermodynamic methods to predict the as-cast microstructure of Nb-bearing austenitic heat-resistant steels.

  7. Polymeric material prepared from Schiff base based on O-carboxymethyl chitosan and its Cu(II) and Pd(II) complexes

    NASA Astrophysics Data System (ADS)

    Baran, Talat; Menteş, Ayfer

    2016-07-01

    In this study, a new eco-friendly Schiff base based on O-carboxymethyl chitosan ([OCMCS-7a]) and its copper(II) and palladium(II) complexes were synthesized. Characterizations of [OCMCS-7a] and its metal complexes were conducted using FTIR, 1H NMR, 13C NMR, TG/DTG, XRD, SEM-EDAX, ICP, UV-VIS, GC-MS, elemental analysis, magnetic moment and molar conductivity measurements. The degree of substitution (DS) of [OCMCS-7a] was determined by elemental analysis to be 0.44. It was shown by the solubility test that [OCMCS-7a] was completely soluble in water. Surface images of chitosan, [OCMCS-7a] and its Cu(II) and Pd(II) complexes were investigated using the SEM-EDAX technique. Their thermal behaviors and crystallinities of the synthesized complexes were determined by TG/DTG and X-ray powder diffraction techniques, respectively. The metal contents of the obtained complexes were determined using an ICP-OES instrument. From the analyses, it was noted that the thermal stabilities and crystallinities of [OCMCS-7a] and its complexes decreased compared to chitosan. As a consequence of surface screening, it was also noted that the surface structure of the chitosan was smoother than that of the obtained compounds.

  8. Novel chelating resin with cyanoguanidine group: useful recyclable materials for Hg(II) removal in aqueous environment.

    PubMed

    Ma, Xiaojie; Li, Yanfeng; Ye, Zhengfang; Yang, Liuqing; Zhou, Lincheng; Wang, Liyuan

    2011-01-30

    A novel chelating resin containing cyanoguanidine moiety has been successfully prepared by the functionalizing reaction of a macroporous bead based on chloromethylated copolymer of styrene-divinylbenzene (CMPS) with dicyandiamide (DCDA) in the presence of phase transfer catalyst. The Fourier transform-infrared spectra (FT-IR) and scanning electron microscopy (SEM) were employed in the characterization of the resulting chelating resin, meanwhile, the adsorption properties of the resin for Hg(II) were investigated by batch and column methods. The results indicated that the resin displayed a marked advantage in Hg(II) binding capacity, and the saturated adsorption capacity estimated from the Langmuir model was dramatically up to 1077 mg g(-1) at 45 °C. Furthermore, it was found that the resin was able to selectively separate Hg(II) from multicomponent solutions with Zn(II), Cu(II), Pb(II) and Mg(II). The desorption process of Hg(II) was tested with different eluents and the ratio of the highest recovery reached to 96% under eluting condition of 1M HCl+10% thiourea. Consequently, the resulting chelating resin would provide a potential application for treatment process of Hg(II) containing wastewater.

  9. Analysis of chlorthalidone polymorphs in raw materials and tablets and the effect of forms I and II on the dissolution properties of drug products.

    PubMed

    Bonfilio, Rudy; Leal, Jockastta S; Santos, Olímpia M M; Pereira, Gislaine R; Doriguetto, Antônio C; de Araújo, Magali B

    2014-01-01

    Chlorthalidone (CTD) is an antihypertensive drug and exhibits four crystalline forms: I, II, III and IV. In this paper, the incidence of CTD polymorphs in raw materials and in tablets as well as the solubility and dissolution properties of forms I and II have been studied. Raw materials were named as A, B, C, D, and E and tablets as Reference, G1, G2 and S. Using powder X-ray diffraction and infrared spectroscopy analyses we found that A, B, E, Reference and G1 contain CTD form I; C, D and S contain predominantly form II; and G2 contain a mixture of both forms. Solubility experiments showed that form II is up to 49% more soluble than form I and dissolution studies showed a significantly effect of the polymorphism on the dissolution of CTD from tablets. Based on these results, it was concluded that only the CTD form I is acceptable for preparation of tablet form. Moreover, we proposed the polymorphic quality control of CTD raw materials and tablets.

  10. GREAT II. Great River Environmental Action Team II. Upper Mississippi River. Guttenberg, Iowa to Saverton, Missouri. Dredged Material Uses Work Group. Appendix.

    DTIC Science & Technology

    1980-12-01

    0 ) (n M IC E an LL> 3 -OL Lu W W.D a) Q a) (v a) 4J~4 4-) >- 4 I- IV L .0 .0 -0 .0 0 S- 0- 0.- 0. . 0. -4-) 4-) 4- 4-) 4.)4. (.0 w L ( (A (A (n) co...dredged material and as such have not tried to find uses for it. c. Road Sanding - Ice Control Channel maintenance dredged material has been used success...with a sewage sludge and sawdust 29 compost in order to create a useful soil additive from waste materials. As stated in their Appendix the study

  11. Experimental study of the thermal stability of materials in high temperature oxygen-containing media

    NASA Technical Reports Server (NTRS)

    Abaltusov, Y. Y.; Bagramyan, A. R.; Grishin, A. M.; Yukhvid, V. I.

    1986-01-01

    An experimental study is made of the interaction of several materials with a high temperature medium containing oxygen. The temperature of the surface was measured as a function of time. It is found that the higher the velocity of mass removal from the surface, the more effective is the material from the viewpoint of heat resistance.

  12. The wet-heat resistance of Bacillus weihenstephanensis KBAB4 spores produced in a two-step sporulation process depends on sporulation temperature but not on previous cell history.

    PubMed

    Baril, E; Coroller, L; Postollec, F; Leguerinel, I; Boulais, C; Carlin, F; Mafart, P

    2011-03-15

    While bacterial spores are mostly produced in a continuous process, this study reports a two-step sporulation methodology. Even though spore heat resistance of numerous spore-forming bacteria is known to be dependent on sporulation conditions, this approach enables the distinction between the vegetative cell growth phase in nutrient broth and the sporulation phase in specific buffer. This study aims at investigating whether the conditions of growth of the vegetative cells, prior to sporulation, could affect spore heat resistance. For that purpose, wet-heat resistance of Bacillus weihenstephanensis KBAB4 spores, produced via a two-step sporulation process, was determined from vegetative cells harvested at four different stages of the growth kinetics, i.e. early exponential phase, late exponential phase, transition phase or early stationary phase. To assess the impact of the temperature on spore heat resistance, sporulation was performed at 10 °C, 20 °C and 30 °C from cells grown during a continuous or a discontinuous temperature process, differentiating or not the growth and sporulation temperatures. Induction of sporulation seems possible for a large range of growth stages. Final spore concentration was not significantly affected by the vegetative cell growth stage while it was by the temperature during growing and sporulation steps. The sporulation temperature influences the heat resistance of B. weihenstephanensis KBAB4 spores much more than growth temperature prior to sporulation. Spores produced at 10 °C were up to 3 times less heat resistant than spores produced at 30 °C.

  13. Effect of the Fine-Grained Structure on the Fatigue Properties of the Heat-Resistant Nickel-Iron Alloy Inconel 718

    NASA Astrophysics Data System (ADS)

    Mukhtarov, Sh. Kh.; Shakhov, R. V.

    2015-10-01

    It is well known that ultrafine-grained nickel alloys with average grain sizes d = 0.1-1 μm possess improved hot workability and can be used for superplastic forming or rolling. However, microstructure refinement can worsen some performance characteristics of the alloy, for example, heat-resistant or fatigue properties. In the present work, fatigue characteristics of the fine-grained alloy Inconel 718 are investigated. Ultrafine-grained alloys with average grain sizes d = 0.1-1 μm were manufactured by multiple forging with stage-by-stage deformation temperature decrease. During standard heat treatment of the alloy performed to obtain the desired properties, the γ-grain size was controlled by precipitations of δ-phase particles along the boundaries. Results of low-cycle fatigue tests of the fine-grained alloy at room and elevated temperatures are compared with the properties of the coarse-grained alloy.

  14. Fire and heat resistant laminating resins based on maleimido and citraconimido substituted 1-(diorgano oxyphosphonyl) methyl -2,4- and -2,6- diaminobenzenes

    NASA Technical Reports Server (NTRS)

    Mikroyannidis, John A. (Inventor); Kourtides, Demetrius A. (Inventor)

    1987-01-01

    A class of fire and heat resistant bisimide resins prepared by thermal polymerization of maleimido or citraconimido substituted 1-((dialkoxyphosphonyl) methyl)-2-4 and -2,6-diaminobenzenes are described. The polymer precursors are prepared by reacting 1-((diorganooxyphosphonyl) methyl)-2-4 and -2,6-diaminobenzenes with maleic anhydride or citraconic anhydride in a mole ratio 1:2. Chain extension of the monomers is achieved by reacting the mono-N-maleimido derivatives of 1-((diorganooxyphosphonyl) methyl)-2,4 and -2,6-diaminobenzenes with aryl tetracarboxylic dianhydrides, such as benzophenone tetracarbocylic dianhydride, or aryl diisocyanates, such as methylenebis (4-phenylisocyanate), in a mole ratio 2:1. The polymerization of the monomers is studied by differential scanning calorimetry (DSC) and the thermal stability of the polymers is ascertained by thermogravimetric analysis (TGA).

  15. Fire and heat resistant laminating resins based on malemeido and citraconimido substituted 1 -2,4- and -2,6- diaminobenzenes

    NASA Technical Reports Server (NTRS)

    Mikroyannidis, John A.; Kourtides, Demetrius A. (Inventor)

    1987-01-01

    A novel class of fire and heat resistant bisimide resins prepared by thermal polymerization of maleimido or citraconimido substituted 1-(dialkox phosphonyl) methyl-2-4 and -2,6-diamino benzenes was presented. The polymer precursors are prepared by reacting 1-(diorgano oxyphosphonyl) methyl-2-4- and -2,6-diamino benzenes with maliec anhydride or citraconic anhydride in a mole ratio 1:2. Chain extension of the monomers is achieved by reacting the mono-N-maleimido derivaties of 1 (diorgano oxyphosphonyl) methyl -2,4- and -2,6-diamino benzenes with aryl tetracarboxylic dianhydrides, such as benzophenone tetracarboxylic dianhydride, or aryl diisocyanates, such as methylene bis(4-phenyl isocyanate), in a mole ratio 2:1. The polymerization of the monomers is studied by diferential scanning calorimetry and the thermal stability of the polymers is ascertained by thermogravimetric analysis.

  16. Effect of welding thermal cycles on the oxidation resistance of 9 wt.% Cr heat resistant steels in 550 °C lead-bismuth eutectic

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Rong, Lijian; Li, Dianzhong; Lu, Shanping

    2016-12-01

    The oxidation resistance for the heat affected zone (HAZ) and base metal of 9 wt.% Cr heat resistant steel in 550 °C lead-bismuth eutectic has been investigated. The oxide film presents a three-layer structure. The outer layer is Fe3O4 while the inner layer is mainly FeCr2O4. The oxide film thickness becomes thinner and thinner in turns of the coarse grained HAZ, fine grained HAZ, inter-critical HAZ and base metal. The oxygen diffusion is the rate determining step during the oxidation process. The Cr-enriched M23C6 plays a significant role on the oxidation rate at the initial stage of oxidation. Increasing the carbon content is a useful method to improve the oxidation resistance.

  17. Mechanism of competitive grain growth in a curvilinear channel of crystal-sorter during the orientational solidification of nickel-based heat-resistant alloy

    NASA Astrophysics Data System (ADS)

    Monastyrskiy, V. P.; Pozdnyakov, A. N.; Ershov, M. Yu.; Monastyrskiy, A. V.

    2017-07-01

    Using numerical simulation in the ProCAST program complex, the conditions of the solidification of heat-resistant nickel alloy in curvilinear channels of a ceramic mold have been investigated. It has been shown that, in practically important cases, the vector of the temperature gradient is oriented along the axis of the curvilinear channel. In a spiral crystal selector, a cyclic change in the preferred direction of growth occurs because of the cyclic change in the direction of the vector of the temperature gradient. The fact that the vector of the temperature gradient is almost always directed along the axis of the curvilinear channel makes it possible to govern the orientation of the vector of the temperature gradient in space and, therefore, to obtain a grain with the preferred crystallographic orientation. Based on the results of this investigation, a method of the grain selection with a desired azimuthal orientation is proposed.

  18. Creep Behavior at 1273 K (1000 °C) in Nb-Bearing Austenitic Heat-Resistant Cast Steels Developed for Exhaust Component Applications

    NASA Astrophysics Data System (ADS)

    Zhang, Yinhui; Li, Mei; Godlewski, Larry A.; Zindel, Jacob W.; Feng, Qiang

    2016-07-01

    A series of Nb-bearing austenitic heat-resistant cast steels with variations of N/C ratios were investigated, and the morphological change of Nb(C,N) from faceted blocks, mixed flake-blocks to "Chinese-script" was observed as N/C ratios decreased. The creep behavior of these alloys was studied at 1273 K (1000 °C), and the longest creep life and lowest creep rate occurred in model alloys with script Nb(C,N). Residual δ-ferrites and (Cr,Fe)23C6 were adverse to creep properties. This work indicates that the control of N/C ratio is required for the as-cast microstructural strengthening.

  19. Development of carbon nanotubes/CoFe2O4 magnetic hybrid material for removal of tetrabromobisphenol A and Pb(II).

    PubMed

    Zhou, Lincheng; Ji, Liqin; Ma, Peng-Cheng; Shao, Yanming; Zhang, He; Gao, Weijie; Li, Yanfeng

    2014-01-30

    Multi-walled carbon nanotubes (MWCNTs) coated with magnetic amino-modified CoFe2O4 (CoFe2O4-NH2) nanoparticles (denoted as MNP) were prepared via a simple one-pot polyol method. The MNP composite was further modified with chitosan (CTS) to obtain a chitosan-functionalized MWCNT/CoFe2O4-NH2 hybrid material (MNP-CTS). The obtained hybrid materials were characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectrogram (FT-IR) Analysis and X-ray Photoelectron Spectroscopy (XPS) Analysis, Vibrating Sample Magnetometer (VSM) Analysis and the Brunauer-Emmett-Teller (BET) surface area method, respectively. The composites were tested as adsorbents for tetrabromobisphenol A (TBBPA) and Pb(II), and were investigated using a pseudo-second-order model. The adsorption of TBBPA was well represented by the Freundlich isotherm; the Langmuir model better described Pb(II) absorption. MNP-CTS adsorbed both TBBPA and Pb(II) (maximum adsorption capacities of 42.48 and 140.1mgg(-1), respectively) better than did MNP without CTS. Magnetic composite particles with adsorbed TBBPA and Pb(II) could be regenerated using 0.2M NaOH solution and were separable from liquid media using a magnetic field.

  20. Heat resistance of Escherichia coli O157:H7 in a nutrient medium and in ground beef patties as influenced by storage and holding temperatures.

    PubMed

    Jackson, T C; Hardin, M D; Acuff, G R

    1996-03-01

    Stationary-phase cultures of Escherichia coli O157:H7 were inoculated into tryptic soy broth, sealed in vials, and stored at -18 degrees C for 1, 8, and 15 days, or 3 or 15 degrees C for 3, 6, and 9 h. Thermal resistance was determined at 55 degrees C. Each storage treatment was repeated with additional holding at 23 or 30 degrees C for 1, 2, 3, or 4 h prior to heating to simulate potential temperature abuse during handling. Cultures under treatments enabling the growth of E. coli O157:H7 were generally more heat sensitive than those held at temperatures which restricted growth or enabled growth to stationary phase. Cultures stored frozen (-18 degrees C) without holding at elevated temperatures had greater heat resistance than those stored under refrigeration (3 degrees C) or at 15 degrees C. Subsequent holding of frozen cultures at 23 or 30 degrees C resulted in a decrease in heat resistance. To determine whether these responses would be observed under typical commercial preparation procedures, ground beef patties were inoculated with E. coli O157:H7 and stored at 3 or 15 degrees C for 9 h or at -18 degrees C for 8 d and then held at 21 or 30 degrees C for 0 or 4 h. Patties were grilled to an internal temperature of 54.4 degrees C (130 degrees F), 62.8 degrees C (145 degrees F), or 68.3 degrees C (155 degrees F). Cultures were most resistant in frozen patties, while cultures in patties stored at 15 degrees C were the most heat sensitive. Holding patties at 21 or 30 degrees C prior to grilling resulted in increased sensitivity. Storage and holding temperatures similar to those encountered in food service may influence the ability of E. coli O157:H7 to survive heat treatments.

  1. Effect of sporulation medium on wet-heat resistance and structure of Alicyclobacillus acidoterrestris DSM 3922-type strain spores and modeling of the inactivation kinetics in apple juice.

    PubMed

    Molva, Celenk; Baysal, Ayse Handan

    2014-10-17

    Alicyclobacillus acidoterrestris is a spoilage bacterium in fruit juices leading to high economic losses. The present study evaluated the effect of sporulation medium on the thermal inactivation kinetics of A. acidoterrestris DSM 3922 spores in apple juice (pH3.82±0.01; 11.3±0.1 °Brix). Bacillus acidocaldarius agar (BAA), Bacillus acidoterrestris agar (BATA), malt extract agar (MEA), potato dextrose agar (PDA) and B. acidoterrestris broth (BATB) were used for sporulation. Inactivation kinetic parameters at 85, 87.5 and 90°C were obtained using the log-linear model. The decimal reduction times at 85°C (D85°C) were 41.7, 57.6, 76.8, 76.8 and 67.2min; D87.5°C-values were 22.4, 26.7, 32.9, 31.5, and 32.9min; and D90°C-values were 11.6, 9.9, 14.7, 11.9 and 14.1min for spores produced on PDA, MEA, BATA, BAA and BATB, respectively. The estimated z-values were 9.05, 6.60, 6.96, 6.15, and 7.46, respectively. The present study suggests that the sporulation medium affects the wet-heat resistance of A. acidoterrestris DSM 3922 spores. Also, the dipicolinic acid content (DPA) was found highest in heat resistant spores formed on mineral containing media. After wet-heat treatment, loss of internal volume due to the release of DPA from spore core was observed by scanning electron microscopy. Since, there is no standardized media for the sporulation of A. acidoterrestris, the results obtained from this study might be useful to determine and compare the thermal resistance characteristics of A. acidoterrestris spores in fruit juices. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Performance Oriented Packaging Testing of Tank, Cartridge, 3 IN/50, Mk 5 Mods 0, 1, 2 for Packing Group II Solid Hazardous Materials.

    DTIC Science & Technology

    1993-04-01

    NUMBERS Performance Oriented Packaging Testing of Tank, D I k T Cartridge, 3*/50, Mk 5 Mods 0 , 1, 2 for Packing Group 11t~~c Solid Hazardous Materials r...due to their similarities in design, size, and weight, this test is considered representative of qualifica- tion testing for the Mk 5 Mods 0 , 2 3"/50...TANK, CARTRIDGE, 3"/50, MK 5 MODS 0 , 1, 2 FOR PACKING GROUP II SOLID HAZARDOUS MATERIALS Author: Karcn McDonnell Mechanical Engineer Performing

  3. Water decontamination via the removal of Pb (II) using a new generation of highly energetic surface nano-material: Co(+2)Mo(+6) LDH.

    PubMed

    Mostafa, Mohsen S; Bakr, Al-Sayed A; El Naggar, Ahmed M A; Sultan, El-Sayed A

    2016-01-01

    CoMo(CO3(2-)) layered double hydroxide of a highly energetic surface, as a new LDH consisting of divalent and hexavalent cations (M(+2)/M(+6)-LDH), was prepared by a homogeneous co-precipitation method. The structure and morphology of the prepared material was confirmed by several analytical techniques namely; X-ray diffraction analysis (XRD), X-ray fluorescence (XRF), Fourier transform infra-red (FT-IR) spectroscopy, differential scanning calorimetry and thermal gravimetric analysis (DSC-TGA), N2 adsorption-desorption isotherm and scanning electron microscope (SEM). The highly energetic surface of the prepared LDH was demonstrated via the X-ray photoelectron spectroscopy (XPS). The surface energy is due to the formation of +4 surface charges in the brucite layer between Co(+2) and Mo(+6). The prepared LDH was applied as a novel adsorbent for the removal of Pb (II) from its aqueous solution at different experimental conditions of time, temperature and initial Pb (II) concentrations. The change of the Pb (II) concentrations; due to adsorption, was monitored by atomic absorption spectrophotometer (AAS). The maximum uptake of Pb (II) by the Co Mo LDH was (73.4 mg/g) at 298 K. The Pb (II) adsorption was found to follow Langmuir isotherm and pseudo second order model. The adsorption process was spontaneous and endothermic. The interference of other cations on the removal of the Pb (II) was studied. Na(+) and K(+) were found to increase the adsorption capacity of the Co Mo LDH toward Pb (II) while it was slightly decreased by the presence of Mn(+2) and Cu(+2). The synthesized LDH showed a great degree of recoverability (7 times) while completely conserving its parental morphology and adsorption capacity. The mechanism of the lead ions removal had exhibited more reliability through a surface adsorption by the coordination between the Mo(+6) of the brucite layers and the oxygen atoms of the nitrates counter ions.

  4. Effects of Cryogenic Treatment on the Strength Properties of Heat Resistant Stainless Steel (07X16H6)

    NASA Astrophysics Data System (ADS)

    Nadig, D. S.; Bhat, M. R.; Pavan, V. K.; Mahishi, Chandan

    2017-09-01

    Cryogenic treatment on metals is a well known technology where the materials are exposed to cryogenic temperature for prolonged time duration. The process involves three stages viz. slow cooling, holding at cryogenic temperature and warming to room temperature. During this process, hard and micro sized carbide particles are released within the steel material. In addition, soft and unconverted austenite of steel changes to strong martensite structure. These combined effects increase the strength and hardness of the cryotreated steel. In this experimental study, the effects of cryogenic treatment, austenitising and tempering on the mechanical properties of stainless steel (07X16H6) have been carried. After determining the strength properties of the original material, the specimens were cryotreated at 98K for 24 hours in a specially developed cryotreatment system. The effects of austenitising prior to cryogenic treatment and tempering post cryotreatment on the mechanical properties of steel samples have been experimentally determined and analysed.

  5. A study of the static and dynamic adsorption of Zn(II) ions on carbon materials from aqueous solutions.

    PubMed

    Alvarez-Merino, Miguel A; López-Ramón, Victoria; Moreno-Castilla, Carlos

    2005-08-15

    The effect of surface oxidation, solution pH, and ionic strength on the adsorption of Zn(II) ions from aqueous solution under static conditions was studied using commercial activated carbons in the form of grains and cloth. In addition, the effects of surface oxidation and the presence of dissolved natural organic matter (tannic acid) were studied under dynamic conditions using activated carbon cloth column beds. Under static conditions, surface oxidation largely increased Zn2+ uptake and two H+ ions were displaced from the oxidized carbon surface per Zn(II) ion adsorbed. It is proposed that adsorption of Zn(II) on the as-received basic carbons was due to C(pi)-cation interactions. An increase in solution pH in the range 3-6 increased Zn(II) uptake, whereas an increase in ionic strength decreased Zn(II) uptake because of the screening effect of the added salt. In the experiments carried out with carbon column beds, the oxidized activated carbon cloth was also more effective than the as-received carbon to remove Zn(II) ions. In this case, the presence of tannic acid decreased the efficiency of the oxidized activated carbon cloth bed to remove Zn(II) ions. An increase in the tannic acid initial concentration had a greater effect on the removal of tannic acid than on the removal of Zn(II) by the column bed. This may be a consequence of the greater size of tannic acid molecules and their low affinity for oxidized carbon surfaces.

  6. BEATRIX-II Program: ANNEX-III to IEA implementing agreement for a programme of research and development on radiation damage in fusion materials

    SciTech Connect

    Slagle, O.D.; Hollenberg, G.W.

    1992-12-01

    The BEATRIX-II experiment is an International Energy Agency (IEA) sponsored collaborative experiment between Japan, Canada, and the United States. This is an in situ tritium recovery experiment conducted to evaluate the performance of ceramic solid breeder materials in a fast neutron environment to high burnup levels. The experiment was carried out in the Fast Flux Test Facility (FFTF), located on the Hanford site near Richland, Washington, and was operated by Westinghouse Hanford Company (WHC). Pacific Northwest Laboratory, Richland (PNL), Richland, Washington, together with the Japan Atomic Energy Research Institute (JAERI) and Atomic Energy of Canada Limited (AECL) Research are conducting the experiment. The objective of the BEATRIX-II experiment is to design, conduct, and evaluate the in situ recovery of tritium from solid breeder materials during neutron irradiation in the FFTF. During the experiment, the performance of candidate solid breeder materials is continuously monitored with respect to temperature stability and tritium release. The phase I experiment was irradiated to lithium burnups of 5% while the goal for Phase II was to irradiate to burnups as high as 8%.

  7. Preliminary plans to move the special nuclear material supporting category I and II missions from TA-18 to the device assembly facility

    SciTech Connect

    Haag, William Earl; Nicholas, N. J.; Mann, P.

    2004-01-01

    In December 2002, the National Nuclear Security Agency (NNSA) issued a Record of Decision announcing its intent to relocate safeguards Category I and II missions and associated special nuclear materials (SNM) from Los Alamos National Laboratory (LANL) Technical Area 18 (TA-18) to the Device Assembly Facility (DAF) at the Nevada Test Site (NTS). The Cat I and II missions support nuclear criticality safety, nuclear emergency response, nuclear nonproliferation, and homeland security. TA-18 is the sole remaining facility in the United States with the capability to perform general-purpose nuclear materials handling experiments and training. Hands-on and remote control experiments, measurements, and training with special materials and devices are conducted. The conceptual design for modifying the DAF to house these Cat I and II missions includes plans for packaging and transporting the SNM inventory associated with the missions. This paper discusses these preliminary packaging and transporting plans, including how they fit into the plans for transitioning the relevant TA- 18 missions to DAF while ensuring that mission, cost, and schedule requirements are met.

  8. Tunable PhoXonic Band Gap Materials from Self-Assembly of Block Copoliymers and Colloidal Nanocrystals (NBIT Phase II)

    DTIC Science & Technology

    2011-05-06

    interaction with photons and phonons. Concerning this, we seek to develop methods and understanding to create both periodically structured materials ...this, we seek to develop methods and understanding to create both periodically structured materials (Bragg gap materials ) and non-periodically...Final Report for AOARD Grant 1014069 “Tunable PhoXonic Band Gap Materials from Self-Assembly of Block Copoliymers and Colloidal Nanocrystals

  9. Removal of Cu(II) in aqueous media by biosorption using water hyacinth roots as a biosorbent material.

    PubMed

    Zheng, Jia-Chuan; Feng, Hui-Min; Lam, Michael Hon-Wah; Lam, Paul Kwan-Sing; Ding, Yan-Wei; Yu, Han-Qing

    2009-11-15

    Water hyacinth roots were employed as a biosorbent to remove Cu(II) in aqueous media. Nitrogen adsorption/desorption analysis revealed that the biosorbent was mesoporous with a relatively small surface area. Equilibrium biosorption isotherms showed that the water hyacinth roots possessed a high affinity and sorption capacity for Cu(II) with a monolayer sorption capacity of 22.7 mg g(-1) at initial pH 5.5. Kinetics study at different temperatures revealed that the sorption was a rapid and endothermic process. The activation energy for Cu(II) sorption was estimated to be 30.8 kJ mol(-1), which is typical of activated chemisorption processes. The sorption mechanism was investigated by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, effect of pH and calcium release. These analyses suggested that the biosorption mainly involved the ion exchange of Cu(II) with cations and complex formation with functional groups on the surface of the roots. All the results showed that water hyacinth roots are an alternative low-cost biosorbent for the removal of Cu(II) from aqueous media.

  10. Fractionally distilled SRC-I, SRC-II, EDS, H-Coal and ITSL direct coal liquefaction process materials: a comparative summary of chemical analysis and biological testing

    SciTech Connect

    Wright, C.W.; Later, D.W.; Dauble, D.D.; Wilson, B.W.

    1985-07-01

    This document reports and compares the results compiled from chemical analyses and biological testing of coal liquefaction process materials which were fractionally distilled, after production, into various comparable boiling-point range cuts. Comparative analyses were performed on solvent refined coal (SRC)-I, SRC-II, H-Coal, EDS an integrated two-stage liquefaction (ITSL) distillate materials. Mutagenicity and carcinogenicity assays were conducted in conjunction with chromatographic and mass spectrometric analyses to provide detailed, comparative, chemical and biological assessments. Where possible, results obtained from the distillate cuts are compared to those from coal liquefaction materials with limited boiling ranges. Work reported here was conducted by investigators in the Biology and Chemistry Department at the Pacific Northwest Laboratory (PNL), Richland, WA. 38 refs., 16 figs., 27 tabs.

  11. Role of general stress-response alternative sigma factors σ(S) (RpoS) and σ(B) (SigB) in bacterial heat resistance as a function of treatment medium pH.

    PubMed

    Ait-Ouazzou, A; Mañas, P; Condón, S; Pagán, R; García-Gonzalo, D

    2012-02-15

    This investigation aimed to determine the role of general stress-response alternative sigma factors σ(S) (RpoS) and σ(B) (SigB) in heat resistance and the occurrence of sublethal injuries in cell envelopes of stationary-phase Escherichia coli BJ4 and Listeria monocytogenes EGD-e cells, respectively, as a function of treatment medium pH. Given that microbial death followed first-order inactivation kinetics (R(2)>0.95) the traditional D(T) and z values were used to describe the heat inactivation kinetics. Influence of rpoS deletion was constant at every treatment temperature and pH, making a ΔrpoS deletion mutant strain approximately 5.5 times more heat sensitive than its parental strain for every studied condition. Furthermore, the influence of the pH of the treatment medium on the reduction of the heat resistance of E. coli was also constant and independent of the treatment temperature (average z value=4.9°C) in both parental and mutant strains. L. monocytogenes EGD-e z values obtained at pH 7.0 and 5.5 were not significantly different (p>0.05) in either parental or the ∆sigB deletion mutant strains (average z value=4.8°C). Nevertheless, at pH 4.0 the z value was higher (z=8.4°C), indicating that heat resistance of both L. monocytogenes strains was less dependent on temperature at pH 4.0. At both pH 5.5 and 7.0 the influence of sigB deletion was constant and independent of the treatment temperature, decreasing L. monocytogenes heat resistance approximately 2.5 times. In contrast, the absence of sigB did not decrease the heat resistance of L. monocytogenes at pH 4.0. The role of RpoS in protecting cell envelopes was more important in E. coli (4 times) than SigB in L. monocytogenes (1.5 times). Moreover, the role of σ(S) in increasing heat resistance seems more relevant in enhancing the intrinsic resilience of the cytoplasmic membrane, and to a lesser extent, outer membrane resilience. Knowledge of environmental conditions related to the activation of

  12. Comparative evaluation of microleakage in Class II restorations using open vs. closed centripetal build-up techniques with different lining materials

    PubMed Central

    Sawani, Shefali; Arora, Vipin; Jaiswal, Shikha; Nikhil, Vineeta

    2014-01-01

    Background: Evaluation of microleakage is important for assessing the success of new restorative materials and methods. Aim and Objectives: Comparative evaluation of microleakage in Class II restorations using open vs. closed centripetal build-up techniques with different lining materials. Materials and Methods: Standardized mesi-occlusal (MO) and distoocclusal (DO) Class II tooth preparations were preparedon 53 molars and samples were randomly divided into six experimental groups and one control group for restorations. Group 1: Open-Sandwich technique (OST) with flowable composite at the gingival seat. Group 2: OST with resin-modified glass ionomer cement (RMGIC) at the gingival seat. Group 3: Closed-Sandwich technique (CST) with flowable composite at the pulpal floor and axial wall. Group 4: CST with RMGIC at the pulpal floor and axial wall. Group 5: OST with flowable composite at the pulpal floor, axial wall, and gingival seat. Group 6: OST with RMGIC at the pulpal floor, axial wall, and gingival seat. Group 7: Control — no lining material, centripetal technique only. After restorations and thermocycling, apices were sealed and samples were immersed in 0.5% basic fuchsin dye. Sectioning was followed by stereomicroscopic evaluation. Results: Results were analyzed using Post Hoc Bonferroni test (statistics is not a form of tabulation). Cervical scores of control were more than the exprimental groups (P < 0.05). Less microleakage was observed in CST than OST in all experimental groups (P < 0.05). However, insignificant differences were observed among occlusal scores of different groups (P > 0.05). Conclusion: Class II composite restorations with centripetal build-up alone or when placed with CST reduces the cervical microleakage when compared to OST. PMID:25125847

  13. Evaluation of a single cell and candidate materials with high water content hydrogen in a generic solid oxide fuel cell stack test fixture, Part II: materials and interface characterization

    SciTech Connect

    Chou, Y. S.; Stevenson, Jeffry W.; Choi, Jung-Pyung

    2013-01-01

    A generic solid oxide fuel cell (SOFC) test fixture was developed to evaluate candidate materials under realistic conditions. A commerical 50 mm x 50 mm NiO-YSZ anode supported thin YSZ electrolyte cell with lanthanum strontium manganite (LSM) cathode was tested to evaluate the stability of candidate materials. The cell was tested in two stages at 800oC: stage I of low (~3% H2O) humidity and stage II of high (~30% H2O) humidity hydrogen fuel at constant voltage or constant current mode. Part I of the work was published earlier with information of the generic test fixture design, materials, cell performance, and optical post-mortem analysis. In part II, detailed microstructure and interfacial characterizations are reported regarding the SOFC candidate materials: (Mn,Co)-spinel conductive coating, alumina coating for sealing area, ferritic stainless steel interconnect, refractory sealing glass, and their interactions with each other. Overall, the (Mn,Co)-spinel coating was very effective in minimizing Cr migration. No Cr was identified in the cathode after 1720h at 800oC. Aluminization of metallic interconnect also proved to be chemically compatible with alkaline-earth silicate sealing glass. The details of interfacial reaction and microstructure development are discussed.

  14. Ignition of nonmetallic materials by impact of high-pressure oxygen. II - Evaluation of repeatability of pneumatic impact test

    NASA Technical Reports Server (NTRS)

    Schmidt, Naomi; Moffett, Gary E.; Pedley, Michael D.; Linley, Larry J.

    1989-01-01

    The gaseous oxygen pneumatic impact test is used to evaluate the suitability of nonmetallic materials for use in high-pressure oxygen systems. The test was evaluated by testing the reactivity of four materials over a range of impact pressures. The evaluation also investigated the effect of valve opening time and other test variables on the frequency of reaction. The variability of the data obtained for each test material was too large for the test method to be capable of distinguishing other than gross differences in the reactivity of materials. No relation was found between this variability and changes in valve opening time and other test variables. The materials studied were found to be unacceptable for use as reference standards. Because of the high variability of the test data, it is recommended that new methods be developed for evaluating the suitability of materials for use in high-pressure oxygen systems.

  15. Ignition of nonmetallic materials by impact of high-pressure oxygen. II - Evaluation of repeatability of pneumatic impact test

    NASA Technical Reports Server (NTRS)

    Schmidt, Naomi; Moffett, Gary E.; Pedley, Michael D.; Linley, Larry J.

    1989-01-01

    The gaseous oxygen pneumatic impact test is used to evaluate the suitability of nonmetallic materials for use in high-pressure oxygen systems. The test was evaluated by testing the reactivity of four materials over a range of impact pressures. The evaluation also investigated the effect of valve opening time and other test variables on the frequency of reaction. The variability of the data obtained for each test material was too large for the test method to be capable of distinguishing other than gross differences in the reactivity of materials. No relation was found between this variability and changes in valve opening time and other test variables. The materials studied were found to be unacceptable for use as reference standards. Because of the high variability of the test data, it is recommended that new methods be developed for evaluating the suitability of materials for use in high-pressure oxygen systems.

  16. Control of charge transfer in a series of Ru2(II,II)/TCNQ two-dimensional networks by tuning the electron affinity of TCNQ units: a route to synergistic magnetic/conducting materials.

    PubMed

    Miyasaka, Hitoshi; Motokawa, Natsuko; Matsunaga, Satoshi; Yamashita, Masahiro; Sugimoto, Kunihisa; Mori, Tatsuya; Toyota, Naoki; Dunbar, Kim R

    2010-02-10

    The isostructural series of two-dimensional (2-D) fishnet-type network compounds, [{Ru(2)(O(2)CCF(3))(4)}(2)(TCNQR(x))] x n(solv) (R(x) = H(4), 1; Br(2), 2; Cl(2), 3; F(2), 4; F(4), 5), has been synthesized from the reactions of a paddlewheel diruthenium(II, II) complex, [Ru(2)(II,II)(O(2)CCF(3))(4)], and neutral TCNQ derivatives (TCNQR(x) = 2,3,5,6- or 2,5-halogen-substituted 7,7,8,8-tetracyanoquinodimethane) under anaerobic conditions. Corresponding Rh compounds 1-Rh-5-Rh, which are diamagnetic and redox-inactive, were also synthesized for the purpose of comparison with 1-5. According to the electron affinity of TCNQR(x), which is related to its first reduction potential, the Ru(2) series (1-5) has the requisite driving force for charge transfer from [Ru(2)(II,II)(O(2)CCF(3))(4)] to TCNQR(x), which can lead to a mixed-valence state of [{Ru(2)(4.5+)}-(TCNQR(x)(*-))-{Ru(2)(4.5+)}] for the 2-D network. Such a charge (or electron) transfer results in magnetic exchange interactions between [Ru(2)] units (S = 1 for [Ru(2)(II,II)] and S = 3/2 for [Ru(2)(II,III)](+)) via TCNQR(x)(*-) S = 1/2 radicals that lead to long-range magnetic ordering in the layer. In the present series, only 5 demonstrated the full electron transfer (1-e(-) transfer) to the mixed-valence state, whereas other members are essentially in the state [{Ru(2)(4+)}-(TCNQR(x)(0))-{Ru(2)(4+)}]. Whereas 1-4 are paramagnetic, 5 is a metamagnet undergoing 3-D long-range antiferromagnetic ordering at 95 K (= T(N)) and reverts to a magnetic-field-induced ferromagnetic state exhibiting coercivity up to 60 K. This result is consistent with the fact that TCNQF(4) has the strongest electron affinity among the TCNQR(x) molecules. Even in neutral forms, however, 1-4 can be observed to undergo thermally and/or field-activated charge transfers from [Ru(2)(II,II)] to TCNQR(x) to give semiconductors with an activation energy of 200-300 meV, which is a driving force to transport electrons over the lattice. As determined

  17. A Fast, Versatile Nanoprobe for Complex Materials: The Sub-micron Resolution X-ray Spectroscopy Beamline at NSLS-II (491st Brookhaven Lecture)

    SciTech Connect

    Thieme, Juergen

    2014-02-06

    Time is money and for scientists who need to collect data at research facilities like Brookhaven Lab’s National Synchrotron Light Source (NSLS), “beamtime” can be a precious commodity. While scanning a complex material with a specific technique and standard equipment today would take days to complete, researchers preparing to use brighter x-rays and the new sub-micron-resolution x-ray spectroscopy (SRX) beamline at the National Synchrotron Light Source II (NSLS-II) could scan the same sample in greater detail with just a few hours of beamtime. Talk about savings and new opportunities for researchers! Users will rely on these tools for locating trace elements in contaminated soils, developing processes for nanoparticles to deliver medical treatments, and much more. Dr. Thieme explains benefits for next-generation research with spectroscopy and more intense x-rays at NSLS-II. He discusses the instrumentation, features, and uses for the new SRX beamline, highlighting its speed, adjustability, and versatility for probing samples ranging in size from millimeters down to the nanoscale. He will talk about complementary beamlines being developed for additional capabilities at NSLS-II as well.

  18. High Tc ferrimagnetic organic-inorganic hybrid materials with MnII-L-MnII and MnII-NC-NbIV linkages (L=pyrazine, pyrazine-N,N'-dioxide, bipyrimidine).

    PubMed

    Podgajny, Robert; Pinkowicz, Dawid; Korzeniak, Tomasz; Nitek, Wojciech; Rams, Michał; Sieklucka, Barbara

    2007-11-26

    A series of heterobimetallic, cyano-bridged 3D inorganic-organic hybrid networks with MnII-L-MnII and MnII-NC-NbIV linkages are reported. Reaction of [Mn(H2O)6]2+ with [Nb(CN)8]4- in the presence of organic linker L (pyrazine (pyz), pyrazine-N,N'-dioxide (pzdo), and 2,2'-bipyrimidine (bpym)) in H2O affords {MnII2(pz)2(H2O)4[NbIV(CN)8]}.pz.3H2O (1), {MnII2(pzdo)(H2O)4[NbIV(CN)8]}.5H2O (2), and {MnII2(bpym)(H2O)2[NbIV(CN)8]} (3), respectively. 1-3 were examined by X-ray crystallography and vibrational and magnetochemical studies. 1 is characterized by the coexistence of 3D inorganic cyano-bridged and 1D organic [Mn-(micro-pyz)]n2n+ sublattices along with the presence of monocoordinated and crystallization molecules of pyrazine. Assemblies 2 and 3 exhibit dimeric {MnII2-(micro-L)}4+ coordination motifs. The magnetic behavior of heterobimetallic 1-3 complexes is dominated by antiferromagnetic coupling between MnII and NbIV centers mediated by cyano bridges, resulting in long-range ferrimagnetic ordering with a high TC of 27 (1), 37 (2), and 50 K (3). The magneto-structural correlation leads to the conclusion that the magnitude of TC is related to the type of coordination polyhedra of [Nb(CN)8] moieties (SAPR (1), intermediate between SAPR and DD (2), and DD (3)), the relative number of cyano bridges per Mn2Nb unit, and coexistence of inorganic and organic connectivity. FC/ZFC responses appear to be sensitive to the degree of organic connectivity. The discussion of magneto-structural correlation is based on the spin-density properties of adequate heterobimetallic systems containing octacyanometalates.

  19. Multi-scale defect interactions in high-rate failure of brittle materials, Part II: Application to design of protection materials

    NASA Astrophysics Data System (ADS)

    Tonge, Andrew L.; Ramesh, K. T.

    2016-01-01

    Micromechanics based damage models, such as the model presented in Part I of this 2 part series (Tonge and Ramesh, 2015), have the potential to suggest promising directions for materials design. However, to reach their full potential these models must demonstrate that they capture the relevant physical processes. In this work, we apply the multiscale material model described in Tonge and Ramesh (2015) to ballistic impacts on the advanced ceramic boron carbide and suggest possible directions for improving the performance of boron carbide under impact conditions. We simulate both dynamic uniaxial compression and simplified ballistic loading geometries to demonstrate that the material model captures the relevant physics in these problems and to interrogate the sensitivity of the simulation results to some of the model input parameters. Under dynamic compression, we show that the simulated peak strength is sensitive to the maximum crack growth velocity and the flaw distribution, while the stress collapse portion of the test is partially influenced by the granular flow behavior of the fully damaged material. From simulations of simplified ballistic impact, we suggest that the total amount of granular flow (a possible performance metric) can be reduced by either a larger granular flow slope (more angular fragments) or a larger granular flow timescale (larger fragments). We then discuss the implications for materials design.

  20. Fabrication of Transparent Nanohybrids with Heat Resistance Using High-Density Amorphous Formation and Uniform Dispersion of Nanodiamond.

    PubMed

    Al Mamun, Muhammad Abdullah; Soutome, Youichi; Kasahara, Yusuke; Meng, Qi; Akasaka, Shuichi; Fujimori, Atsuhiro

    2015-08-19

    A new technology for the production of transparent material using a "crystalline" polymer is proposed in the present study. Further, transparent and flexible crystalline polymer nanohybrid film containing well-dispersed nanodiamond filler was fabricated. Partially fluorinated crystalline polymer with switchboard-type lamellae results in high transparency as a consequence of the formation of a high-density amorphous structure based on high-temperature drawing just below the melting point at 110 °C. Although the formation of nanohybrid materials composed of fluorinated-polymer/organo-modified nanocarbon is generally difficult, we confirmed the formation, via melt-compounding, using atomic force microscopy and wide-angle X-ray diffraction. Even though the polymer matrix/nanodiamond hybrid has remarkable aggregation properties, a well-dispersed state was achieved because of improvement in wettability obtained through surface modification of filler. The resulting nanohybrid demonstrates transparency, increased thermal degradation temperature, and enhanced mechanical properties, which seem to be derived from the nucleation effect caused by the adsorption of the terminal polymer chain onto the organic modifier.

  1. Materials

    NASA Technical Reports Server (NTRS)

    Glaessgen, Edward H.; Schoeppner, Gregory A.

    2006-01-01

    NASA Langley Research Center has successfully developed an electron beam freeform fabrication (EBF3) process, a rapid metal deposition process that works efficiently with a variety of weldable alloys. The EBF3 process can be used to build a complex, unitized part in a layer-additive fashion, although the more immediate payoff is for use as a manufacturing process for adding details to components fabricated from simplified castings and forgings or plate products. The EBF3 process produces structural metallic parts with strengths comparable to that of wrought product forms and has been demonstrated on aluminum, titanium, and nickel-based alloys to date. The EBF3 process introduces metal wire feedstock into a molten pool that is created and sustained using a focused electron beam in a vacuum environment. Operation in a vacuum ensures a clean process environment and eliminates the need for a consumable shield gas. Advanced metal manufacturing methods such as EBF3 are being explored for fabrication and repair of aerospace structures, offering potential for improvements in cost, weight, and performance to enhance mission success for aircraft, launch vehicles, and spacecraft. Near-term applications of the EBF3 process are most likely to be implemented for cost reduction and lead time reduction through addition of details onto simplified preforms (casting or forging). This is particularly attractive for components with protruding details that would require a significantly large volume of material to be machined away from an oversized forging, offering significant reductions to the buy-to-fly ratio. Future far-term applications promise improved structural efficiency through reduced weight and improved performance by exploiting the layer-additive nature of the EBF3 process to fabricate tailored unitized structures with functionally graded microstructures and compositions.

  2. Developing and Testing Simulated Occupational Experiences for Distributive Education Students in Rural Communities: Volume II: Curriculum Materials: Final Report.

    ERIC Educational Resources Information Center

    Virginia Polytechnic Inst. and State Univ., Blacksburg.

    Volume 2 of a three-volume final report presents curriculum materials developed as part of a research project which pilot tested a distributive education program for rural schools utilizing a retail store simulation plan. The materials for the two-year curriculum consist of "Competency Area Packets" (addressed to the student) for the following…

  3. Nontrivial Berry phase and type-II Dirac transport in the layered material PdT e2

    NASA Astrophysics Data System (ADS)

    Fei, Fucong; Bo, Xiangyan; Wang, Rui; Wu, Bin; Jiang, Juan; Fu, Dongzhi; Gao, Ming; Zheng, Hao; Chen, Yulin; Wang, Xuefeng; Bu, Haijun; Song, Fengqi; Wan, Xiangang; Wang, Baigeng; Wang, Guanghou

    2017-07-01

    We report on a systematic study of type-II Dirac fermions in a layered crystal of PdT e2 . De Haas-van Alphen oscillations show a small Fermi-surface pocket with a cross section of 0.077 n m-2 with a nontrivial Berry phase. First-principles calculation reveals that the nontrivial Berry phase originates from a hole pocket formed by the tilted Dirac cone. In addition, the band dispersion measured with angle-resolved photoemission spectroscopy is found to be consistent with that of a type-II Dirac cone dispersion. We propose that PdT e2 is an improved platform to host topological superconductors.

  4. Comparative evaluation of microleakage in Class II restorations using open vs. closed centripetal build-up techniques with different lining materials.

    PubMed

    Sawani, Shefali; Arora, Vipin; Jaiswal, Shikha; Nikhil, Vineeta

    2014-07-01

    Evaluation of microleakage is important for assessing the success of new restorative materials and methods. Comparative evaluation of microleakage in Class II restorations using open vs. closed centripetal build-up techniques with different lining materials. Standardized mesi-occlusal (MO) and distoocclusal (DO) Class II tooth preparations were preparedon 53 molars and samples were randomly divided into six experimental groups and one control group for restorations. Group 1: Open-Sandwich technique (OST) with flowable composite at the gingival seat. Group 2: OST with resin-modified glass ionomer cement (RMGIC) at the gingival seat. Group 3: Closed-Sandwich technique (CST) with flowable composite at the pulpal floor and axial wall. Group 4: CST with RMGIC at the pulpal floor and axial wall. Group 5: OST with flowable composite at the pulpal floor, axial wall, and gingival seat. Group 6: OST with RMGIC at the pulpal floor, axial wall, and gingival seat. Group 7: Control - no lining material, centripetal technique only. After restorations and thermocycling, apices were sealed and samples were immersed in 0.5% basic fuchsin dye. Sectioning was followed by stereomicroscopic evaluation. Results were analyzed using Post Hoc Bonferroni test (statistics is not a form of tabulation). Cervical scores of control were more than the exprimental groups (P < 0.05). Less microleakage was observed in CST than OST in all experimental groups (P < 0.05). However, insignificant differences were observed among occlusal scores of different groups (P > 0.05). Class II composite restorations with centripetal build-up alone or when placed with CST reduces the cervical microleakage when compared to OST.

  5. Compatibility of refrigerants and lubricants with motor materials under retrofit conditions. Final report, Volume II - data tables, high pressure refrigerants

    SciTech Connect

    Doerr, R.G.; Waite, T.D.

    1996-10-01

    Compatibility tests were conducted on motor materials to determine if exposure to the original refrigerant/mineral oil would affect compatibility of the motor materials after retrofit to the alternative refrigerant/lubricant. The motor materials were exposed at elevated temperature to the original refrigerant and mineral oil for 500 hours, followed by exposure to the alternative refrigerant and lubricant for 500 hours. Measurements were also taken after 168 and 336 hours. As a control, some samples were exposed to the original refrigerant/mineral oil for a total of 1000 hours.

  6. Tetra methyl substituted Cu(II) phthalocyanine as alternative hole transporting material for organometal halide perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Sfyri, Georgia; Kumar, Challuri Vijay; Wang, Yu-Long; Xu, Zong-Xiang; Krontiras, C. A.; Lianos, Panagiotis

    2016-01-01

    Copper phthalocyanine is a promising hole transporting material, which can be employed with solid state perovskite solar cells. Tetra methyl substituted copper phthalocyanine was presently studied as a hole transporting material and demonstrated improved performance with respect to unsubstituted copper phthalocyanine. This material shows a strong absorption in the Visible and Near IR part of the electromagnetic spectrum contributing to the absorption of photons. Its LUMO and HOMO level are favourably positioned for injecting electrons and scavenging holes. Methyl substitution facilitates closer molecular packing leading to a stronger extinction coefficient, stronger Ͽ⿿Ͽ interaction and higher charge carrier mobility.

  7. Development of a new heat resistant austenitic stainless steel ``NAR-AH-4'' for power generation equipment

    SciTech Connect

    Kajigaya, Ichiro; Namba, Kazuo; Nishiyama, Yoshitaka; Sawaragi, Yoshiatsu

    1999-07-01

    New austenitic stainless steel, NAR-AH-4, which consists of low Si-23 mass %Cr-11.5 %Ni-0.2%N-B-REM (Rare Earth metal) has been developed for the application of high temperature components (up to 1,000 C) in thermal power plants and chemical plants. The corrosion and erosion resistance of developed steel with high content of chromium and slight amount of REM is excellent in forming adherent chromia oxide film on a surface. The creep rupture strength is considerably higher than that of Type 310S(24Cr-20Ni) and Alloy 800H(20Cr032Ni-Al,Ti) due to the addition of nitrogen and boron. The resistance to weld hot cracking sensitivity of this steel is better than Type 310S and high silicon content (0.3%) and optimum ratio of chromium equivalent to nickel equivalent. In addition, this steel has an economical advantage over Type 310S and Alloy 800H. These results indicate that this steel is expected to be widely utilized as a candidate material for high temperature components.

  8. BEATRIX-II Program, January 1989--December 1989: ANNEX-III to IEA implementing agreement for a programme of research and development on radiation damage in fusion materials

    SciTech Connect

    Slagle, O.D.; Hollenberg, G.W.

    1990-10-01

    BEATRIX-II is an International Energy Agency (IEA) sponsored collaborative experiment among Japan, Canada, and the United States. The purpose of the experiment is to evaluate the performance of ceramic solid breeder materials in a fast neutron environment. To do this, an in-situ tritium recovery experiment is being conducted in the Fast Flux Test Facility (FFTF), located on the Hanford site near Richland, Washington, and operated by Westinghouse Hanford Company (WHC). The Pacific Northwest Laboratory (PNL), Richland, Washington, together with the Japan Atomic Energy Research Institute (JAERI) and Atomic Energy of Canada Limited (AECL) are responsible for conducting the experiment.

  9. Non-aggregated Zn(ii)octa(2,6-diphenylphenoxy) phthalocyanine as a hole transporting material for efficient perovskite solar cells.

    PubMed

    Javier Ramos, F; Ince, M; Urbani, M; Abate, Antonio; Grätzel, M; Ahmad, Shahzada; Torres, T; Nazeeruddin, Mohammad Khaja

    2015-06-21

    A non-aggregated Zn(ii)octa(2,6-diphenylphenoxy) phthalocyanine (coded as TT80) has been used as a hole-transporting material for perovskite solar cells. The cells were fabricated under three different configurations by changing the uptake solvent (chlorobenzene or toluene) and incorporating additives (bis(trifluoromethane) sulfonimide lithium salt (LiTFSI) and 4-tert-butylpyridine (TBP). A power conversion efficiency of 6.7% (AM1.5G standard conditions) was achieved for the best cell under optimized configuration.

  10. Theoretical design and material growth of Type-II Antimonide-based superlattices for multi-spectral infrared detection and imaging

    NASA Astrophysics Data System (ADS)

    Hoang, Anh Minh

    Infrared detectors find applications in many aspects of life, from night vision, target tracking for homeland security and defense, non-destructive failure detection in industry, chemical sensing in medicine, and free-space communication. Currently, the dominant technologies of photodetectors based upon HgCdTe and InSb are experiencing many limitations. Under this circumstance, the Type-II InAs/GaSb/AlSb superlattices which have been intensively studied recently appear to be an excellent candidate to give breakthroughs in the infrared technology. The Type-II SLs with theirs advantages such as great flexibility in bandgap engineering, high carrier effective mass, Auger recombination suppression and high uniformity have shown excellent device performance from MWIR to VLWIR. In the era of the third generation for infrared cameras, Type-II SLs are entering the new phase of development with high performance and multi-spectral detection. The goal of this work is to investigate quantum properties of the superlattice system, design appropriate device architectures and experimentally fabricate infrared detectors which can push further the limit of this material system and outperform existing competing technologies. The binary-binary InAs/GaSb superlattice has gone through much transformation over the years. Incorporating compounds lattice matched to the 6.1A family has invited more possibilities to band engineer the Type-II SLs. For the first time, by employing all three members of this material system, we have designed a new superlattice structure and demonstrated shortwavelength infrared (SWIR) photodiodes based on Type-II InAs/GaSb/AlSb with high electrical and optical performance. The photodiodes exhibited a quantum efficiency of 60% with very low dark current, can be operated at room temperature. In addition to the range of MWIR to VLWIR, a new channel of detection has been added to the GaSb based type-II SL material system. The new realization of SWIR photodiodes has

  11. Material transport from the near shore to the basinal environment in the southern Baltic Sea. II: Synthesis of data on origin and properties of material

    NASA Astrophysics Data System (ADS)

    Emeis, K.; Christiansen, C.; Edelvang, K.; Jähmlich, S.; Kozuch, J.; Laima, M.; Leipe, T.; Löffler, A.; Lund-Hansen, L. C.; Miltner, A.; Pazdro, K.; Pempkowiak, J.; Pollehne, F.; Shimmield, T.; Voss, M.; Witt, G.

    2002-07-01

    The Pomeranian Bight (southern Baltic Sea) is a mixing zone between waters of the Baltic Proper and the river Oder, which drains a densely populated and highly industrialised catchment of central Europe. The bight is a nondepositional area, and all material produced in its water column, from erosion of strata at the seafloor and cliffs, and delivered by rivers, is transported near the seafloor to the depositional areas of the Arkona, Bornholm and Gdansk basins. In this contribution, we assess the origin, transformation and mass fluxes of material through the bight based on an integrated field study conducted in the period 1996-1998. The transport mechanism is by wave- and current-induced resuspension and settling cycles, which effectively enrich organic-rich material and associated substances (organic pollutants, heavy metals) in deeper water; the estimated transport time is less than 6 months. The phases in which the material is transported are suspended matter in the water column, a particle- and aggregate-rich benthic boundary layer of <1 m above the seafloor and a layer of fluffy material fed from the two other sources that covers the sandy near-shore sediments as a discrete phase; it collects up to 130 g m -2 of particulate material after quiescent periods lasting several days. It is easily resuspended at shear velocities around 5 cm s -1 and is recycled into the suspended matter and benthic boundary layer pools of material. In deeper waters (>20 m water depth), the fluffy layer is not readily distinguished from the underlying soft, organic-rich sediment and the change in physical and chemical properties is gradual. The organic matter passing through the coastal zone in the southern Baltic is unaffected by biological or chemical modifications in composition. We find no evidence for a preferential removal of nitrogen or phosphorus, even if the speciation of phosphorus changes from biological compounds to minerals. The compositional changes which we see, i

  12. Well wrapped eggs: effects of egg shell structure on heat resistance and hatchling mass in the invasive land snail Cornu aspersum.

    PubMed

    Nicolai, Annegret; Vernon, Philippe; Lenz, Roman; Le Lannic, Joseph; Briand, Valérie; Charrier, Maryvonne

    2013-02-01

    In ectotherms, the temperature changes that accompany climate shifts, microhabitat changes, and species range extensions can have profound effects on the performance of organisms. The aim of this laboratory study on the terrestrial invasive gastropod Cornu aspersum was to investigate the effect of dietary calcium source on egg shell structure and heat resistance of eggs in two populations from different climatic regions of France (Western Atlantic and Mediterranean). To date no literature is known about heat stress in calcified ectothermic eggs while exposed to heat peaks using fluctuating thermal regimes and optimal humidity. In snails from the Mediterranean population fed exclusively with CaCO(3) from limestone we found the thinnest egg shells and the smallest hatchlings. Limestone represents the most accessible calcium source for snails, but is, however, responsible for thinner and more mineralized egg shells (higher ash content). Hence thicker egg shells result from a low mineralized mucopolysaccharide-glycoprotein matrix that could play a nutritional role for hatchlings. Exposed to heat peaks, eggs in both populations had lower incubation time variability at the detriment of hatching rate. This study highlights the need for functional studies in this invasive species to understand the effects on population dynamics of interacting biotic and abiotic environmental factors under climate and anthropic habitat changes. Copyright © 2013 Wiley Periodicals, Inc.

  13. Fat and fibre interfere with the dramatic effect that nanoemulsified d-limonene has on the heat resistance of Listeria monocytogenes.

    PubMed

    Maté, Javier; Periago, Paula M; Ros-Chumillas, María; Grullón, Coralin; Huertas, Juan Pablo; Palop, Alfredo

    2017-04-01

    The application of d-limonene in form of nanoemulsion has been proved to reduce dramatically the thermal resistance of Listeria monocytogenes in culture media. The present research shows very promising results on the application in food products. The thermal resistance of L. monocytogenes was reduced 90 times when 0.5 mM nanoemulsified d-limonene was added to apple juice. This is the biggest reduction in the heat resistance of a microorganism caused by an antimicrobial described ever. However, no effect was found in carrot juice. A carrot juice system was prepared in an attempt to unravel which juice constituents were responsible for the lack of effect. When fat and fibre were not included in the carrot juice system formulation, the thermal resistance of L. monocytogenes was, again, dramatically reduced in presence of nanoemulsified d-limonene, so these components were shown to interfere with the effect. Once this interaction with food constituents becomes solved, the addition of nanoemulsified antimicrobials would allow to reduce greatly the intensity of the thermal treatments currently applied in the food processing industry.

  14. Effect of aging temperature on the microstructures and mechanical properties of ZG12Cr9Mo1Co1NiVNbNB ferritic heat-resistant steel

    NASA Astrophysics Data System (ADS)

    Yang, Xue; Sun, Lan; Xiong, Ji; Zhou, Ping; Fan, Hong-yuan; Liu, Jian-yong

    2016-02-01

    The effect of aging on the mechanical properties and microstructures of a new ZG12Cr9Mo1Co1NiVNbNB ferritic heat resistant steel was investigated in this work to satisfy the high steam parameters of the ultra-supercritical power plant. The results show that the main precipitates during aging are Fe(Cr, Mo)23C6, V(Nb)C, and (Fe2Mo) Laves in the steel. The amounts of the precipitated phases increase during aging, and correspondingly, the morphologies of phases are similar to be round. Fe(Cr, Mo)23C6 appears along boundaries and grows with increasing temperature. In addition, it is revealed that the martensitic laths are coarsened and eventually happen to be polygonization. The hardness and strength decrease gradually, whereas the plasticity of the steel increases. What's more, the hardness of this steel after creep is similar to that of other 9%-12%Cr ferritic steels. Thus, ZG12Cr9Mo1Co1NiVNbNB can be used in the project.

  15. Kinetics of the Formation of Intermetallic Phases in HP-Type Heat-Resistant Alloys at Long-Term High-Temperature Exposure

    NASA Astrophysics Data System (ADS)

    Kondrat'ev, Sergey Yu.; Anastasiadi, Grigoriy P.; Petrov, Sergey N.; Ptashnik, Alina V.

    2017-01-01

    The kinetics of formation and morphology of the intermetallic phases in the structure of heat-resistant as-cast HP40NbTi alloys in the course of long high-temperature exposure have been studied with the help of light and electron microscopy, electron microprobe, and X-ray diffraction. During exposure of 2 to 1000 hours at 1423 K (1150 °C), intermetallic phase with conditional formula Cr7Ni5Si3N3FeNb is formed in the alloy. The analysis of the kinetics of intermetallic phase's growth for an impact assessment of certain metal substitutional elements (niobium, chromium, silicon) on the size of the formed particles was performed. Formation and growth of the intermetallic phases with high silicon content in the alloy structure on the boundaries between niobium and chromium carbides (NbC and M23C6) and matrix γ-phase provide a diffusion barrier for oxygen in oxidizing environment. This may create partial protection against oxidation of hardening carbide phases in the structure and promote increasing of the serviceability of the HP series alloys under operating conditions in the petrochemical industry.

  16. Fire and heat resistant laminating resin based on maleimido and citraconimido substituted 1-(diorganooxyphosphonyl-methyl)-2,4- and -2,6-diaminobenzenes

    NASA Technical Reports Server (NTRS)

    Beggs, James M. (Inventor); Mikroyannidis, John A. (Inventor); Kourtides, Demetrius A. (Inventor)

    1988-01-01

    The subject invention pertains to a novel class of fire-and heat-resistant bisimide resins prepared by thermal polymerization of maleimido or citraconimido substituded 1-(dialkoxyphosphonyl)-methyl-2-4 and -2,6-diaminobenzenes. Typical polymer presursors have the chemical structure wherein R is alkyl, substituted alkyl or aryl, and R sup 1 is hydrogen or lower alkyl. The polymer precursors are prepared by reacting 1-(diorganooxyphosphonyl)methyl-2-4 and -2,6-diaminobenzenes with maleic anhydride or citraconic anhydride in a mole ratio 1:2. Chains extension of the monomers is achieved by reacting the mono-N-maleimido derivatives of 1-(diorganooxyphosphonyl)methyl-2,4 and -2,6-diaminobenzenes with aryl tetracarboxylic dianhydrides, such as benzophenone tetracarboxylic diandydride, or aryl diisocyanates, such as methylenebis (4-phenylisocyanate), in a mole ratio 2:1. The polymerization of the monomers is studied by differential scanning calorimetry (DSC) and the thermal stability of the polymers is ascertained by thermogravimetric analysis (TGA).

  17. Comparison of Chemical Sensitivity of Fresh and Long-Stored Heat Resistant Neosartorya fischeri Environmental Isolates Using BIOLOG Phenotype MicroArray System

    PubMed Central

    Panek, Jacek; Frąc, Magdalena; Bilińska-Wielgus, Nina

    2016-01-01

    Spoilage of heat processed food and beverage by heat resistant fungi (HRF) is a major problem for food industry in many countries. Neosartorya fischeri is the leading source of spoilage in thermally processed products. Its resistance to heat processing and toxigenicity makes studies about Neosartorya fischeri metabolism and chemical sensitivity essential. In this study chemical sensitivity of two environmental Neosartorya fischeri isolates were compared. One was isolated from canned apples in 1923 (DSM3700), the other from thermal processed strawberry product in 2012 (KC179765), used as long-stored and fresh isolate, respectively. The study was conducted using Biolog Phenotype MicroArray platforms of chemical sensitivity panel and traditional hole-plate method. The study allowed for obtaining data about Neosartorya fischeri growth inhibitors. The fresh isolate appeared to be much more resistant to chemical agents than the long-stored isolate. Based on phenotype microarray assay nitrogen compounds, toxic cations and membrane function compounds were the most effective in growth inhibition of N. fischeri isolates. According to the study zaragozic acid A, thallium(I) acetate and sodium selenate were potent and promising N. fischeri oriented fungicides which was confirmed by both chemical sensitivity microplates panel and traditional hole-plate methods. PMID:26815302

  18. [Reactive oxygen forms and Ca ions as possible intermediaries under the induction of heat resistance of plant cells by jasmonic acid].

    PubMed

    Karpets, Iu V; Kolupaev, Iu E; Iastreb, T O; Oboznyĭ, A I; Shvidenko, N V; Lugovaia, A A; Vaĭner, A A

    2013-01-01

    The participation of reactive oxygen species (ROS) and calcium ions in realization of influence of exogenous jasmonic acid (JA) on the heat resistance of wheat coleoptiles has been investigated. Influence of 1 microM JA caused the transitional intensifying of generation of superoxide anion-radical (O2*-) and hydrogen peroxide in coleoptiles with the maximum within 15-30 minutes after the treatment beginning. Within the first hour after the beginning of coleoptiles treatment with JA the increase of superoxide dismutase (SOD) activity was noted. Later on (within 5-24 hours after the treatment beginning) there was the lowering of ROS generation by coleoptiles of experimental variant, and the SOD activity approached the control value. Intensifying of generation of superoxide radical induced by JA was suppressed by the antioxidant ionol and was partially levelled by imidazole (inhibitor of NADPH-oxidase), EGTA (chelator of extracellular calcium) and lanthanum chloride (calcium channels blocker). Pretreatment of coleoptiles with the ionol, imidazole, EGTA and LaC3l3 also partially removed the effect of increase of their resistance to the damaging heating caused by exogenous JA. It is supposed that the ROS generated with participation NADPH-oxidase, which activity depends on the receipt of calcium ions from extracellular space in the cytosol, are involved in realization of physiological effects of JA.

  19. Ani s 11-Like Protein Is a Pepsin- and Heat-Resistant Major Allergen of Anisakis spp. and a Valuable Tool for Anisakis Allergy Component-Resolved Diagnosis.

    PubMed

    Carballeda-Sangiao, Noelia; Rodríguez-Mahillo, Ana I; Careche, Mercedes; Navas, Alfonso; Caballero, Teresa; Dominguez-Ortega, Javier; Jurado-Palomo, Jesús; González-Muñoz, Miguel

    2016-01-01

    Anisakis simplex is a fish parasite responsible for gastrointestinal and allergic symptoms in humans. The Ani s 11-like protein has been proposed as an Anisakis allergen because its primary structure is similar to that of Ani s 11. The aims of this work were to analyse the frequency of detection of the Ani s 11-like protein and assess its diagnostic value. rAni s 11-like protein, rAni s 5 and rAni s 4 were expressed in Escherichia coli and rAni s 1 was produced in Pichia pastoris. Recombinant allergen detection patterns in 37 Anisakis-sensitised patients were determined. The stability to pepsin digestion and heat treatment of rAni s 11-like protein was also analysed by IgE immunoblotting. Ani s 11-like protein is a major allergen detected by 78% of Anisakis-allergic patients, and 13.5% of patients detect only the rAni s 11-like allergen. This allergen is heat stable because it retains its capability of binding IgE after boiling for 30 min and it is resistant to pepsin digestion for 120 min. These data indicate that the Ani s 11-like protein is a pepsin- and heat-resistant major allergen (Ani s 11.0201) of Anisakis spp. and a valuable tool for Anisakis allergy component-resolved diagnosis. © 2016 S. Karger AG, Basel.

  20. Comparison of Chemical Sensitivity of Fresh and Long-Stored Heat Resistant Neosartorya fischeri Environmental Isolates Using BIOLOG Phenotype MicroArray System.

    PubMed

    Panek, Jacek; Frąc, Magdalena; Bilińska-Wielgus, Nina

    2016-01-01

    Spoilage of heat processed food and beverage by heat resistant fungi (HRF) is a major problem for food industry in many countries. Neosartorya fischeri is the leading source of spoilage in thermally processed products. Its resistance to heat processing and toxigenicity makes studies about Neosartorya fischeri metabolism and chemical sensitivity essential. In this study chemical sensitivity of two environmental Neosartorya fischeri isolates were compared. One was isolated from canned apples in 1923 (DSM3700), the other from thermal processed strawberry product in 2012 (KC179765), used as long-stored and fresh isolate, respectively. The study was conducted using Biolog Phenotype MicroArray platforms of chemical sensitivity panel and traditional hole-plate method. The study allowed for obtaining data about Neosartorya fischeri growth inhibitors. The fresh isolate appeared to be much more resistant to chemical agents than the long-stored isolate. Based on phenotype microarray assay nitrogen compounds, toxic cations and membrane function compounds were the most effective in growth inhibition of N. fischeri isolates. According to the study zaragozic acid A, thallium(I) acetate and sodium selenate were potent and promising N. fischeri oriented fungicides which was confirmed by both chemical sensitivity microplates panel and traditional hole-plate methods.