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Sample records for shelled pecans definitions

  1. Safety studies conducted on pecan shell fiber, a food ingredient produced from ground pecan shells

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    Laurie Dolan

    Full Text Available Use of pecan shell fiber in human food is presently limited, but could increase pending demonstration of safety. In a 91-day rat study, pecan shell fiber was administered at dietary concentrations of 0 (control, 50 000, 100 000 or 150 000 ppm. There was no effect of the ingredient on body weight of males or females or food consumption of females. Statistically significant increases in food consumption were observed throughout the study in 100 000 and 150 000 ppm males, resulting in intermittent decreases in food efficiency (150 000 ppm males only that were not biologically relevant. All animals survived and no adverse clinical signs or functional changes were attributable to the test material. There were no toxicologically relevant changes in hematology, clinical chemistry or urinalysis parameters or organ weights in rats ingesting pecan shell fiber. Any macroscopic or microscopic findings were incidental, of normal variation and/or of minimal magnitude for test substance association. Pecan shell fiber was non-mutagenic in a bacterial reverse mutation test and non-clastogenic in a mouse peripheral blood micronucleus test. Based on these results, pecan shell fiber has an oral subchronic (13-week no observable adverse effect level (NOAEL of 150 000 ppm in rats and is not genotoxic at the doses analyzed. Keywords: Pecan shell, Fiber, Rat, Diet, Toxicity, Mutagenicity

  2. Safety studies conducted on pecan shell fiber, a food ingredient produced from ground pecan shells.

    Science.gov (United States)

    Dolan, Laurie; Matulka, Ray; Worn, Jeffrey; Nizio, John

    2016-01-01

    Use of pecan shell fiber in human food is presently limited, but could increase pending demonstration of safety. In a 91-day rat study, pecan shell fiber was administered at dietary concentrations of 0 (control), 50 000, 100 000 or 150 000 ppm. There was no effect of the ingredient on body weight of males or females or food consumption of females. Statistically significant increases in food consumption were observed throughout the study in 100 000 and 150 000 ppm males, resulting in intermittent decreases in food efficiency (150 000 ppm males only) that were not biologically relevant. All animals survived and no adverse clinical signs or functional changes were attributable to the test material. There were no toxicologically relevant changes in hematology, clinical chemistry or urinalysis parameters or organ weights in rats ingesting pecan shell fiber. Any macroscopic or microscopic findings were incidental, of normal variation and/or of minimal magnitude for test substance association. Pecan shell fiber was non-mutagenic in a bacterial reverse mutation test and non-clastogenic in a mouse peripheral blood micronucleus test. Based on these results, pecan shell fiber has an oral subchronic (13-week) no observable adverse effect level (NOAEL) of 150 000 ppm in rats and is not genotoxic at the doses analyzed.

  3. Safety studies conducted on pecan shell fiber, a food ingredient produced from ground pecan shells

    OpenAIRE

    Dolan, Laurie; Matulka, Ray; Worn, Jeffrey; Nizio, John

    2015-01-01

    Use of pecan shell fiber in human food is presently limited, but could increase pending demonstration of safety. In a 91-day rat study, pecan shell fiber was administered at dietary concentrations of 0 (control), 50 000, 100 000 or 150 000 ppm. There was no effect of the ingredient on body weight of males or females or food consumption of females. Statistically significant increases in food consumption were observed throughout the study in 100 000 and 150 000 ppm males, resulting in intermitt...

  4. Evaluation of sanitizers for inactivating Salmonella on in-shell pecans and pecan nutmeats.

    Science.gov (United States)

    Beuchat, Larry R; Mann, David A; Alali, Walid Q

    2012-11-01

    Chlorine, organic acids, and water extracts of inedible pecan components were tested for effectiveness in killing Salmonella on pecans. In-shell pecans and nutmeats (U.S. Department of Agriculture medium pieces) were immersion inoculated with a mixture of five Salmonella serotypes, dried to 3.7% moisture, and stored at 4°C for 3 to 6 weeks. In-shell nuts were immersed in chlorinated water (200, 400, and 1,000 μg/ml), lactic acid (0.5, 1, and 2%), and levulinic acid (0.5, 1, and 2%) with and without 0.05% sodium dodecyl sulfate (SDS), and a mixed peroxyacid sanitizer (Tsunami 200, 40 μg/ml) for up to 20 min at 21°C. The rate of reduction of free chlorine in conditioning water decreased as the ratio of in-shell nuts/water was increased. The rate of reduction was more rapid when nuts were not precleaned before treatment. The initial population of Salmonella on in-shell nuts (5.9 to 6.3 log CFU/g) was reduced by 2.8 log CFU/g after treating with chlorinated water (1,000 μg/ml). Treatment with 2% lactic acid plus SDS or 2% levulinic acid plus SDS reduced the pathogen by 3.7 and 3.4 log CFU/g, respectively. Lactic and levulinic acids (2%) without SDS were less effective (3.3- and 2.1-log CFU/g reductions, respectively) than acids with SDS. Treatment with Tsunami 200 resulted in a 2.4-log CFU/g reduction. In-shell nuts and nutmeats were immersed in water extracts of ground pecan shucks (hulls), shells, a mixture of shells and pith, and pith. The general order of lethality of extracts to Salmonella was shuck pecans before conditioning in chlorinated water and the need for sanitizers with increased effectiveness in killing Salmonella on pecans.

  5. Adsorption of volatile organic compounds by pecan shell- and almond shell-based granular activated carbons.

    Science.gov (United States)

    Bansode, R R; Losso, J N; Marshall, W E; Rao, R M; Portier, R J

    2003-11-01

    The objective of this research was to determine the effectiveness of using pecan and almond shell-based granular activated carbons (GACs) in the adsorption of volatile organic compounds (VOCs) of health concern and known toxic compounds (such as bromo-dichloromethane, benzene, carbon tetrachloride, 1,1,1-trichloromethane, chloroform, and 1,1-dichloromethane) compared to the adsorption efficiency of commercially used carbons (such as Filtrasorb 200, Calgon GRC-20, and Waterlinks 206C AW) in simulated test medium. The pecan shell-based GACs were activated using steam, carbon dioxide or phosphoric acid. An almond shell-based GAC was activated with phosphoric acid. Our results indicated that steam- or carbon dioxide-activated pecan shell carbons were superior in total VOC adsorption to phosphoric acid-activated pecan shell or almond shell carbons, inferring that the method of activation selected for the preparation of activated carbons affected the adsorption of VOCs and hence are factors to be considered in any adsorption process. The steam-activated, pecan shell carbon adsorbed more total VOCs than the other experimental carbons and had an adsorption profile similar to the two coconut shell-based commercial carbons, but had greater adsorption than the coal-based commercial carbon. All the carbons studied adsorbed benzene more effectively than the other organics. Pecan shell, steam-activated and acid-activated GACs showed higher adsorption of 1,1,1-trichloroethane than the other carbons studied. Multivariate analysis was conducted to group experimental carbons and commercial carbons based on their physical, chemical, and adsorptive properties. The results of the analysis conclude that steam-activated and acid-activated pecan shell carbons clustered together with coal-based and coconut shell-based commercial carbons, thus inferring that these experimental carbons could potentially be used as alternative sources for VOC adsorption in an aqueous environment.

  6. Thermogravimetric characterization and gasification of pecan nut shells.

    Science.gov (United States)

    Aldana, Hugo; Lozano, Francisco J; Acevedo, Joaquín; Mendoza, Alberto

    2015-12-01

    This study focuses on the evaluation of pecan nut shells as an alternative source of energy through pyrolysis and gasification. The physicochemical characteristics of the selected biomass that can influence the process efficiency, consumption rates, and the product yield, as well as create operational problems, were determined. In addition, the thermal decomposition kinetics necessary for prediction of consumption rates and yields were determined. Finally, the performance of a downdraft gasifier fed with pecan nut shells was analyzed in terms of process efficiency and exit gas characteristics. It was found that the pyrolytic decomposition of the nut shells can be modeled adequately using a single equation considering two independent parallel reactions. The performance of the gasification process can be influenced by the particle size and air flow rate, requiring a proper combination of these parameters for reliable operation and production of a valuable syngas. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Efficacy of antimicrobials extracted from organic pecan shell for inhibiting the growth of Listeria spp.

    Science.gov (United States)

    Babu, Dinesh; Crandall, Philip G; Johnson, Casey L; O'Bryan, Corliss A; Ricke, Steven C

    2013-12-01

    Growers and processors of USDA certified organic foods are in need of suitable organic antimicrobials. The purpose of the research reported here was to develop and test natural antimicrobials derived from an all-natural by-product, organic pecan shells. Unroasted and roasted organic pecan shells were subjected to solvent free extraction to produce antimicrobials that were tested against Listeria spp. and L. monocytogenes serotypes to determine the minimum inhibitory concentrations (MIC) of antimicrobials. The effectiveness of pecan shell extracts were further tested using a poultry skin model system and the growth inhibition of the Listeria cells adhered onto the skin model were quantified. The solvent free extracts of pecan shells inhibited Listeria strains at MICs as low as 0.38%. The antimicrobial effectiveness tests on a poultry skin model exhibited nearly a 2 log reduction of the inoculated cocktail mix of Listeria strains when extracts of pecan shell powder were used. The extracts also produced greater than a 4 log reduction of the indigenous spoilage bacteria on the chicken skin. Thus, the pecan shell extracts may prove to be very effective alternative antimicrobials against food pathogens and supplement the demand for effective natural antimicrobials for use in organic meat processing. © 2013 Institute of Food Technologists®

  8. Impact of pecan nut shell aqueous extract on the oxidative properties of margarines during storage.

    Science.gov (United States)

    Engler Ribeiro, Paula Cristina; de Britto Policarpi, Priscila; Dal Bo, Andrea; Barbetta, Pedro Alberto; Block, Jane Mara

    2017-07-01

    The oxidative properties of margarines supplemented with pecan nut shell extract, rosemary extract and butylated hydroxytoluene (BHT) were investigated. The extracts of pecan nut shell and rosemary showed a high content of total phenolics and condensed tannins (93 and 102.9 mg GAE g -1 and 46 and 38.9 mg CE g -1 respectively) as well as a high antioxidant activity (1257 and 2306 µmol TEAC g -1 and 293 and 856 mg TEAC g -1 by ABTS and DPPH methods respectively). Gallic acid, chlorogenic acid, p-hydroxybenzoic acid, epicatechin and epicatechin gallate were identified in the pecan nut shell extract. Peroxide and p-anisidine values of 3.75-4.43 meq kg -1 and 1.22-2.73 respectively, Totox values of 9.88-10.8 and specific extinction values of 4.38-4.59 and 0.92-0.94 at 232 and 268 nm respectively were observed after 8 months of storage in the studied samples. Margarines supplemented with pecan nut shell extract, rosemary extract or BHT during prolonged storage were found to be of equal quality within the degree of confidence limits. The extract of pecan nut shell may be considered as a natural product replacement for the synthetic antioxidant BHT. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  9. Survival and growth of salmonella in high-moisture pecan nutmeats, in-shell pecans, inedible nut components, and orchard soil.

    Science.gov (United States)

    Beuchat, Larry R; Mann, David A

    2010-11-01

    Outbreaks of salmonellosis associated with almonds have raised interest in better understanding the behavior of Salmonella on other tree nuts. We undertook a study to determine the survival and growth characteristics of Salmonella on high-moisture (water activity of 0.96 to 0.99) pecan nutmeats, in-shell pecans, and inedible components (shuck, shell, and middle septum tissue) of in-shell pecans. Salmonella did not grow on high-moisture nutmeat halves, pieces, or granules stored at 4°C for up to 48 h. Growth did occur, however, at 21, 30, and 37°C. Increases of 1.77 to 5.87 log CFU/g of nutmeats occurred within 48 h at 37°C; the order in which nutmeats supported growth was granules > pieces > halves. Populations of Salmonella on and in high-moisture in-shell pecans (kernel water activity of 0.94) stored at 4, 21, 30, and 37°C for 8 days decreased by 0.52 to 1.19 log CFU/g. The pathogen grew on the surface of high-moisture (water activity of 0.99) pecan shucks and shells but died on middle septum tissue stored at 21, 30, and 37°C for up to 6 days. Salmonella died in water extracts of shucks and in pecan orchard soil saturated with water or shuck extract, but survived well for at least 18 weeks in dry soil. The ability of the pathogen to grow on high-moisture nutmeats and some of the inedible components of pecans emphasizes the importance of controlling or limiting the time pecans are exposed to water in preharvest and postharvest environments.

  10. Hepatoprotective effects of pecan nut shells on ethanol-induced liver damage.

    Science.gov (United States)

    Müller, Liz Girardi; Pase, Camila Simonetti; Reckziegel, Patrícia; Barcelos, Raquel C S; Boufleur, Nardeli; Prado, Ana Cristina P; Fett, Roseane; Block, Jane Mara; Pavanato, Maria Amália; Bauermann, Liliane F; da Rocha, João Batista Teixeira; Burger, Marilise Escobar

    2013-01-01

    The hepatoprotective activity of the aqueous extract of the shells of pecan nut was investigated against ethanol-induced liver damage. This by-product of the food industry is popularly used to treat toxicological diseases. We evaluated the phytochemical properties of pecan shell aqueous extract (AE) and its in vitro and ex vivo antioxidant activity. The AE was found to have a high content of total polyphenols (192.4±1.9 mg GAE/g), condensed tannins (58.4±2.2 mg CE/g), and antioxidant capacity, and it inhibited Fe(2+)-induced lipid peroxidation (LP) in vitro. Rats chronically treated with ethanol (Et) had increased plasmatic transaminases (ALT, AST) and gamma glutamyl transpeptidase (GGT) levels (96%, 59.13% and 465.9%, respectively), which were effectively prevented (87; 41 and 383%) by the extract (1:40, w/v). In liver, ethanol consumption increased the LP (121%) and decreased such antioxidant defenses as glutathione (GSH) (33%) and superoxide dismutase (SOD) (47%) levels, causing genotoxicity in erythrocytes. Treatment with pecan shell AE prevented the development of LP (43%), GSH and SOD depletion (33% and 109%, respectively) and ethanol-induced erythrocyte genotoxicity. Catalase activity in the liver was unchanged by ethanol but was increased by the extract (47% and 73% in AE and AE+Et, respectively). Therefore, pecan shells may be an economic agent to treat liver diseases related to ethanol consumption. Copyright © 2011 Elsevier GmbH. All rights reserved.

  11. Antioxidant Properties of Pecan Nut [Carya illinoinensis (Wangenh.) C. Koch] Shell Infusion

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro do Prado, A. C.; Monalise Aragao, A.; Fett, R.; Block, J. M.

    2009-07-01

    The nutritional composition of Pecan nut [Ca rya illinoinensis (Wangenh.) C. Koch] shells and the total phenolic and condensed tannin contents of Pecan nut shell infusion were determined and the antioxidant activity of the infusion was evaluated through ABTS, DPPH and {beta}-carotene/linoleic acid systems. The shell presented high fiber content (48% {+-} 0.06), the total phenolic content ranged from 116 to 167 mg GAE/g and the condensed tannin content was between 35 and 48 mg CE/g. The antioxidant activity varied from 1112 and 1763 {mu}mol TEAC/g in the ABTS system. In the DPPH method, the antioxidant activity was from 305 to 488 mg TEAC/g (30 minutes reaction) and from 482 to 683 mg TEAC/g (24 h reaction). The oxidation inhibition percentage obtained in the {beta}-carotene/linoleic acid system varied from 70 to 96%. The results indicated the high phenolic content and antioxidant activity of Pecan nut shell infusion. (Author) 28 refs.

  12. Evaluation of Toxicological Effects of an Aqueous Extract of Shells from the Pecan Nut Carya illinoinensis (Wangenh.) K. Koch and the Possible Association with Its Inorganic Constituents and Major Phenolic Compounds.

    Science.gov (United States)

    Porto, Luiz Carlos S; da Silva, Juliana; Sousa, Karen; Ambrozio, Mariana L; de Almeida, Aline; Dos Santos, Carla Eliete I; Dias, Johnny F; Allgayer, Mariangela C; Dos Santos, Marcela S; Pereira, Patrícia; Ferraz, Alexandre B F; Picada, Jaqueline N

    2016-01-01

    Background. Industrial processing of the pecan nut Carya illinoinensis K. Koch generated a large amount of shells, which have been used to prepare nutritional supplements and medicinal products; however, the safe use of shells requires assessment. This study evaluated the toxic, genotoxic, and mutagenic effects of pecan shell aqueous extract (PSAE) and the possible contribution of phenolic compounds, ellagic and gallic acids, and inorganic elements present in PSAE to induce toxicity. Results. Levels of inorganic elements like K, P, Cl, and Rb quantified using the Particle-Induced X-Ray Emission method were higher in PSAE than in pecan shells, while Mg and Mn levels were higher in shells. Mice showed neurobehavioral toxicity when given high PSAE doses (200-2,000 mg kg(-1)). The LD50 was 1,166.3 mg kg(-1). However, PSAE (50-200 mg·kg(-1)) and the phenolic compounds (10-100 mg·kg(-1)) did not induce DNA damage or mutagenicity evaluated using the comet assay and micronucleus test. Treatment with ellagic acid (10-100 mg·kg(-1)) decreased triglyceride and glucose levels, while treatments with PSAE and gallic acid had no effect. Conclusion. Pecan shell toxicity might be associated with high concentrations of inorganic elements such as Mn, Al, Cu, and Fe acting on the central nervous system, besides phytochemical components, suggesting that the definition of the safe dose should take into account the consumption of micronutrients.

  13. Phenolic compounds and antioxidant activity of kernels and shells of Mexican pecan (Carya illinoinensis).

    Science.gov (United States)

    de la Rosa, Laura A; Alvarez-Parrilla, Emilio; Shahidi, Fereidoon

    2011-01-12

    The phenolic composition and antioxidant activity of pecan kernels and shells cultivated in three regions of the state of Chihuahua, Mexico, were analyzed. High concentrations of total extractable phenolics, flavonoids, and proanthocyanidins were found in kernels, and 5-20-fold higher concentrations were found in shells. Their concentrations were significantly affected by the growing region. Antioxidant activity was evaluated by ORAC, DPPH•, HO•, and ABTS•-- scavenging (TAC) methods. Antioxidant activity was strongly correlated with the concentrations of phenolic compounds. A strong correlation existed among the results obtained using these four methods. Five individual phenolic compounds were positively identified and quantified in kernels: ellagic, gallic, protocatechuic, and p-hydroxybenzoic acids and catechin. Only ellagic and gallic acids could be identified in shells. Seven phenolic compounds were tentatively identified in kernels by means of MS and UV spectral comparison, namely, protocatechuic aldehyde, (epi)gallocatechin, one gallic acid-glucose conjugate, three ellagic acid derivatives, and valoneic acid dilactone.

  14. The Antidiabetic and Antihypercholesterolemic Effects of an Aqueous Extract from Pecan Shells in Wistar Rats.

    Science.gov (United States)

    Porto, Luiz Carlos S; da Silva, Juliana; Ferraz, Alexandre B F; Ethur, Eduardo M; Porto, Caroline D L; Marroni, Norma P; Picada, Jaqueline N

    2015-12-01

    Pecan shell decoction has been used to treat diabetes and obesity-related diseases. In this study, the effects of a pecan shell aqueous extract (PSAE) were evaluated in diabetic and hypercholesterolemic Wistar rats, analyzing clinical signs and biochemical as well as genotoxic and mutagenic parameters, to assess its safe use and efficacy. Diabetes mellitus and hypercholesterolemia were induced with streptozotocin (STZ) and tyloxapol, respectively. Animals were orally administered PSAE (100 mg/kg body weight, b.w.) for 28 days. Biochemical analyses and genotoxicity were evaluated in blood samples and mutagenicity was evaluated in bone marrow. PSAE treatment decreased the blood glucose level and stabilized clinical signs of diabetes in diabetic rats. PSAE diminished the increase in total cholesterol and triglyceride levels in hypercholesterolemic rats. The urea levels were higher in diabetic rats than in treated ones; however, creatinine values were the same in all groups. Elevated transaminase levels were suggestive of liver injuries in diabetic rats, and were not altered by PSAE treatment. PSAE did not show genotoxic or mutagenic activities in diabetic and hypercholesterolemic rats, indicating its safe use at 100 mg/kg b.w. not only in healthy rats but also in rats with induced metabolic alterations. The findings on PSAE's efficacy may indicate that its successful and popular use is in accordance with our results. Thus, PSAE might be a potential candidate for medical purposes as a complementary treatment of diabetes and hypercholesterolemia.

  15. Pecan shell-based granular activated carbon for treatment of chemical oxygen demand (COD) in municipal wastewater.

    Science.gov (United States)

    Bansode, R R; Losso, J N; Marshall, W E; Rao, R M; Portier, R J

    2004-09-01

    The present investigation was undertaken to compare the adsorption efficiency of pecan shell-based granular activated carbon with the adsorption efficiency of the commercial carbon Filtrasorb 200 with respect to uptake of the organic components responsible for the chemical oxygen demand (COD) of municipal wastewater. Adsorption efficiencies for these two sets of carbons (experimental and commercial) were analyzed by the Freundlich adsorption model. The results indicate that steam-activated and acid-activated pecan shell-based carbons had higher adsorption for organic matter measured as COD, than carbon dioxide-activated pecan shell-based carbon or Filtrasorb 200 at all the carbon dosages used during the experiment. The higher adsorption may be related to surface area as the two carbons with the highest surface area also had the highest organic matter adsorption. These results show that granular activated carbons made from agricultural waste (pecan shells) can be used with greater effectiveness for organic matter removal from municipal wastewater than a coal-based commercial carbon. Copyright 2004 Elsevier Ltd.

  16. Antioxidant Properties of Pecan Nut [Carya illinoinensis (Wangenh. C. Koch] Shell Infusion

    Directory of Open Access Journals (Sweden)

    Fett, Roseane

    2009-09-01

    Full Text Available The nutritional composition of Pecan nut [Carya illinoinensis (Wangenh. C. Koch] shells and the total phenolic and condensed tannin contents of Pecan nut shell infusion were determined and the antioxidant activity of the infusion was evaluated through ABTS, DPPH and β-carotene/linoleic acid systems. The shell presented high fiber content (48% ± 0.06, the total phenolic content ranged from 116 to 167 mg GAE/g and the condensed tannin content was between 35 and 48 mg CE/g. The antioxidant activity varied from 1112 and 1763 μmol TEAC/g in the ABTS system. In the DPPH method, the antioxidant activity was from 305 to 488 mg TEAC/g (30 minutes reaction and from 482 to 683 mg TEAC/g (24 h reaction. The oxidation inhibition percentage obtained in the β-carotene/linoleic acid system varied from 70 to 96%. The results indicated the high phenolic content and antioxidant activity of Pecan nut shell infusion.La composición nutricional de la cáscara de nuez Pecana [Carya illinoinensis (Wangenh. C. Koch] y los contenidos de fenoles totales y de taninos condensados de la infusión de la cáscara de nuez Pecana se determinaron en este trabajo. La actividad antioxidante de la infusión se evaluó a través de los sistemas ABTS, DPPH y β-caroteno/ácido linoleico. La cáscara presentó un contenido elevado de fibras (48% ± 0,06, el contenido de fenoles totales varió de 116 a 167 mg GAE/g y el de taninos condensados se encontró entre 35 y 48 mg CE/g. La actividad antioxidante varió entre 1112 y 1763 μmol TEAC/g en el sistema ABTS. Por el método DPPH, la actividad antioxidante fue de 305 a 488 mg TEAC/g (30 minutos de reacción y de 482 a 683 mg TEAC/g (24 h de reacción. El porcentaje de inhibición de la oxidación que se obtuvo en el sistema β -caroteno/ácido linoleico varió de 70 a 96%. Los resultados indicaron un elevado contenido de fenoles y una elevada actividad antioxidante para la infusión de la cáscara de nuez Pecana.

  17. Influence of gamma irradiation on microbiological and chemical characteristics of shelled and unshelled stored pecan (carya illinoinsis)

    International Nuclear Information System (INIS)

    Abd El Wahab, S.A.E.; El Salhy, F.T.A.; Mahmoud, A.M.

    2010-01-01

    Shelled and unshelled pecan nuts were treated with 0,1.53 and 5 kGy of gamma irradiation . The irradiated and non-irradiated nuts were stored in polyethylene bags for 0,2,4,6, and 8 months at room temperature. Total bacterial count and total mold and yeast, proximate composition (moisture, protein, fat and ash content), total free amino acids, total fatty acids, reducing and non-reducing sugars, phosphorous and potassium of nuts were evaluated immediately after irradiation and after each storage period . The results indicated that gamma irradiation reduced total bacterial count and total fungal load of pecan. Irradiation doses did not cause any significant changes in proximate composition of pecan.

  18. Evaluation of Toxicological Effects of an Aqueous Extract of Shells from the Pecan Nut Carya illinoinensis (Wangenh. K. Koch and the Possible Association with Its Inorganic Constituents and Major Phenolic Compounds

    Directory of Open Access Journals (Sweden)

    Luiz Carlos S. Porto

    2016-01-01

    Full Text Available Background. Industrial processing of the pecan nut Carya illinoinensis K. Koch generated a large amount of shells, which have been used to prepare nutritional supplements and medicinal products; however, the safe use of shells requires assessment. This study evaluated the toxic, genotoxic, and mutagenic effects of pecan shell aqueous extract (PSAE and the possible contribution of phenolic compounds, ellagic and gallic acids, and inorganic elements present in PSAE to induce toxicity. Results. Levels of inorganic elements like K, P, Cl, and Rb quantified using the Particle-Induced X-Ray Emission method were higher in PSAE than in pecan shells, while Mg and Mn levels were higher in shells. Mice showed neurobehavioral toxicity when given high PSAE doses (200–2,000 mg kg−1. The LD50 was 1,166.3 mg kg−1. However, PSAE (50–200 mg·kg−1 and the phenolic compounds (10–100 mg·kg−1 did not induce DNA damage or mutagenicity evaluated using the comet assay and micronucleus test. Treatment with ellagic acid (10–100 mg·kg−1 decreased triglyceride and glucose levels, while treatments with PSAE and gallic acid had no effect. Conclusion. Pecan shell toxicity might be associated with high concentrations of inorganic elements such as Mn, Al, Cu, and Fe acting on the central nervous system, besides phytochemical components, suggesting that the definition of the safe dose should take into account the consumption of micronutrients.

  19. Physicochemical properties of carbons prepared from pecan shell by phosphoric acid activation.

    Science.gov (United States)

    Guo, Yanping; Rockstraw, David A

    2007-05-01

    Activated carbons were prepared from pecan shell by phosphoric acid activation. The pore structure and acidic surface groups of these carbons were characterized by nitrogen adsorption, Boehm titration and transmittance Fourier infrared spectroscopy (FTIR) techniques. The characterization results demonstrated that the development of pore structure was apparent at temperatures 250 degrees C, and reached 1130m(2)/g and 0.34cm(3)/g, respectively, at 500 degrees C. Impregnation ratio and soaking time at activation temperature also affected the pore development and pore size distribution of final carbon products. At an impregnation ratio of 1.5, activated carbon with BET surface area and micropore volume as high as 861m(2)/g and 0.289cm(3)/g was obtained at 400 degrees C. Microporous activated carbons were obtained in this study. Low impregnation ratio (less than 1.5) and activation temperature (less than 300 degrees C) are favorable to the formation of acidic surface functional groups, which consist of temperature-sensitive (unstable at high temperature) and temperature-insensitive (stable at high temperature) two parts. The disappearance of temperature-sensitive groups was significant at temperature 300 degrees C; while the temperature-insensitive groups are stable even at 500 degrees C. FTIR results showed that the temperature-insensitive part was mostly phosphorus-containing groups as well as some carbonyl-containing groups, while carbonyl-containing groups were the main contributor of temperature-sensitive part.

  20. Pecan drying with silica gel

    Energy Technology Data Exchange (ETDEWEB)

    Ghate, S.R.; Chhinnan, M.S.

    1983-07-01

    High moisture in-shell pecans were dried by keeping them in direct and indirect contact with silica gel to investigate their drying characteristics. In-shell pecans were also dried with ambient air from a controlled environment chamber and with air dehumidified by silica gel. Direct contact and dehumidified air drying seemed feasible approaches.

  1. Comparative study between two animal models of extrapyramidal movement disorders: prevention and reversion by pecan nut shell aqueous extract.

    Science.gov (United States)

    Trevizol, Fabiola; Benvegnú, Dalila M; Barcelos, Raquel C S; Pase, Camila S; Segat, Hecson J; Dias, Verônica Tironi; Dolci, Geisa S; Boufleur, Nardeli; Reckziegel, Patrícia; Bürger, Marilise E

    2011-08-01

    Acute reserpine and subchronic haloperidol are animal models of extrapyramidal disorders often used to study parkinsonism, akinesia and tardive dyskinesia. In humans, these usually irreversible and disabling extrapyramidal disorders are developed by typical antipsychotic treatment, whose pathophysiology has been related to oxidative damages development. So far, there is no treatment to prevent these problems of the psychiatric clinic, and therefore further studies are needed. Here we used the animal models of extrapyramidal disorders cited above, which were performed in two distinct experiments: orofacial dyskinesia (OD)/catalepsy induced by acute reserpine and subchronic haloperidol after (experiment 1) and before (experiment 2) oral treatment with pecan shell aqueous extract (AE), a natural and promissory antioxidant. When administered previously (exp.1), the AE prevented OD and catalepsy induced by both reserpine and haloperidol. When reserpine and haloperidol were administered before the extract (exp.2), the animals developed OD and catalepsy all the same. However, the orofacial parameter (but not catalepsy) in both animal models was reversed after 7 and 14 days of AE treatment. These results indicate that, acute reserpine and subchronic haloperidol administrations induced similar motor disorders, although through different mechanisms, and therefore are important animal models to study the physiopathology of extrapyramidal disorders. Comparatively, the pecan shell AE was able to both prevent and reverse OD but only to prevent catalepsy. These results reinforce the role of oxidative stress and validate the two animal models used here. Our findings also favor the idea of prevention of extrapyramidal disorders, rather than their reversal. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Aqueous extract of pecan nut shell (Carya illinoensis [Wangenh.] K. Koch) exerts protection against oxidative damage induced by cyclophosphamide in rat testis.

    Science.gov (United States)

    Benvegnu, Dalila M; Barcelos, Raquel C S; Roversi, Katiane; Boufleur, Nardelli; Pase, Camila S; Trevizol, Fabiola; Segat, Hecson J; Dias, Verônica T; Dolci, Geisa S; Antoniazzi, Caren T D; Reckziegel, Patricia; Lima, Fernanda; de Lima, Luiz A R; de Carvalho, Leandro M; da Silva Junior, Valdemiro A; Burger, Marilise E

    2013-01-01

    This study investigated the protective effect of pecan nut (Carya illinoensis) shell aqueous extract (AE) on the oxidative and morphological status of rat testis treated with cyclophosphamide (CP). Wistar rats received water or AE (5%) ad libitum for 37 days. On day 30, half of each group received a single intraperitoneal administration of vehicle or CP 200 mg/kg. After 7 days, the animals were killed and their testis removed. Rats treated with CP presented reduced levels of lactate dehydrogenase, vitamin C, and gluthatione, as well as decreased catalase activity, increased lipid peroxidation levels and superoxide dismutase activity, no alteration in carbonyl protein levels, and a loss of morphological testicular integrity. In contrast, cotreatment with pecan shell AE totally prevented the decrease of lactate dehydrogenase and vitamin C levels and catalase activity and partially prevented the depletion of gluthatione levels. Moreover, it totally prevented the increase in superoxide dismutase activity and lipid peroxidation levels and maintained testicular integrity. These findings show the protective role of pecan shell AE in CP-induced testicular toxicity. The use of this phytotherapy may be considered to minimize deleterious effects related to this chemotherapy.

  3. Evaluation of the antimicrobial activity of pecan nut [Carya illinoinensis (Wangenh C. Koch] shell aqueous extract on minimally processed lettuce leaves

    Directory of Open Access Journals (Sweden)

    Sabrina CAXAMBÚ

    2016-01-01

    Full Text Available Abstract Pecan nutshell is a residue from food industry that has potential to be used as biopreservative in foods. The objective of this study was to evaluate the antimicrobial activity of pecan nutshell aqueous extract in vitro and its effectiveness to inhibit spoilage microorganisms on lettuce leaves. The results indicate that the aqueous extract presents inhibitory activity against important foodborne pathogenic bacteria such as Listeria monocytogenes, Salmonella Enteritidis, Staphylococcus aureus, Bacillus cereus, Aeromonas hydrophila and Pseudomonas aeruginosa. Antimicrobial activity was not observed against Corynebacterium fimi, Clostridium perfringens, Escherichia coli, and the phytopathogenic fungi tested. When applied onto lettuce leaves, pecan nutshell extract reduced the counts of mesophilic and psychrotrophic bacteria in 2 and 4 log CFU/g, respectively, during storage of leafy for 5 days at refrigeration temperature (5 °C. The extract was not effective to inhibit yeast on lettuce leaves. Thus, the aqueous extract of pecan shell showed great potential to be used as a natural preservative in foods, acting mainly in the inhibition of spoilage and pathogenic bacteria.

  4. Efficacy of sanitizers in reducing Salmonella on pecan nutmeats during cracking and shelling.

    Science.gov (United States)

    Beuchat, Larry R; Mann, David A; Alali, Walid Q

    2013-05-01

    Studies were done to evaluate the efficacy of chlorine (200 to 1,000 μg/ml), lactic acid (0.5 to 2%), levulinic acid (0.5 to 2%), sodium dodecyl sulfate (SDS, 0.05%), lactic acid plus SDS, levulinic acid plus SDS, and a mixed peroxyacid sanitizer (Tsunami 200, 40 and 80 μg/ml) in killing Salmonella on or in immersion- and on surface-inoculated pecan nutmeats (U.S. Department of Agriculture medium pieces and mammoth halves). The addition of SDS to treatment solutions containing lactic acid or levulinic acid resulted in generally higher reductions of Salmonella, but differences in these reductions were not always significant. Lactic and levulinic acids (2%) containing SDS (0.05%) were equivalent in killing Salmonella on immersion-inoculated nutmeats. Tsunami 200 (40 μg/ml) was less lethal or equivalent to 1 or 2% lactic and levulinic acids, with or without 0.05% SDS. Reductions did not exceed 1.1 log CFU/g of immersion-inoculated pieces and halves, regardless of sanitizer concentration or treatment time (up to 20 min). Reductions on surface-inoculated pieces and halves were 0.7 to 2.6 log CFU/g and 1.2 to 3.0 log CFU/g, respectively. Treatment with 2% lactic acid plus SDS (0.05%) and Tsunami (80 μg/ml) was most effective in killing Salmonella on surface-inoculated pieces; treatment of halves with chlorine (1,000 μg/ml) or lactic acid (1 or 2%), with or without SDS, was most efficacious. Exposure of immersion-inoculated pecan pieces to chlorine (200 μg/ml), lactic acid (2%) and levulinic acid (2%) with or without SDS, and Tsunami (80 μg/ml) during intermittent vacuum (18 ± 2 mbar) and ambient atmospheric pressure treatments for up to 20 min reduced Salmonella by only 0.1 to 1.0 log CFU/g. These studies emphasize the importance of preventing contamination of pecan nutmeats with Salmonella. Once nuts are contaminated, the lethality of sanitizers tested in this study is minimal.

  5. 7 CFR 457.167 - Pecan revenue crop insurance provisions.

    Science.gov (United States)

    2010-01-01

    ... include selling through an on-farm or roadside stand, or a farmer's market, or permitting the general... of in-shell pecans grown during a crop year. Harvest—Collecting mature pecans from the orchard. Hedge...—Pecans as they are removed from the orchard with the nut-meats in the shell. Interplanted—Acreage on...

  6. Chemical Characterization and Release of Polyphenols from Pecan Nut Shell [Carya illinoinensis (Wangenh) C. Koch] in Zein Microparticles for Bioactive Applications.

    Science.gov (United States)

    Kureck, Itamara; Policarpi, Priscila de Brito; Toaldo, Isabela Maia; Maciel, Matheus Vinícius de Oliveira Brisola; Bordignon-Luiz, Marilde T; Barreto, Pedro Luiz Manique; Block, Jane Mara

    2018-05-03

    The pecan nut [Carya illinoinensis (Wangenh) C. Koch] is a natural source of polyphenols with antioxidant properties. In this study, the encapsulation of aqueous and hydroalcoholic extracts of pecan nut shell were evaluated for the release of bioactive compounds and antioxidant potential in order to explore food applications using zein as encapsulating agent. The extracts showed high contents of total phenolics, condensed tannins and high antioxidant activity. Concentrations of proanthocyanidins were 9-fold higher in hydroalcoholic extracts. The LC-DAD analysis showed that catechins were the major phenolic compounds in samples, with epigallocatechin levels up to 138.62 mg mL -1 . Zein microparticles loaded with aqueous extract released 2.3 times more phenolic compounds than the hydroalcoholic extracts and the DSC thermograms showed that extracts of pecan nut shell remained thermally stable up to 240 °C. The zein microcapsules obtained in this study were efficiently encapsulated and represent an interesting additive due its high antioxidant capacity, physicochemical characteristics and morphology. The use of zein microparticles combined with natural extracts constitute a step forward in the improvement of current technology for delivering phenolic compounds with applications in functional foods and nutraceuticals.

  7. Screening of commercial and pecan shell-extracted liquid smoke agents as natural antimicrobials against foodborne pathogens.

    Science.gov (United States)

    Van Loo, Ellen J; Babu, D; Crandall, Philip G; Ricke, Steven C

    2012-06-01

    Liquid smoke extracts have traditionally been used as flavoring agents, are known to possess antioxidant properties, and serve as natural alternatives to conventional antimicrobials. The antimicrobial efficacies of commercial liquid smoke samples may vary depending on their source and composition and the methods used to extract and concentrate the smoke. We investigated the MICs of eight commercial liquid smoke samples against Salmonella Enteritidis, Staphylococcus aureus, and Escherichia coli . The commercial liquid smoke samples purchased were supplied by the manufacturer as water-based or concentrated extracts of smoke from different wood sources. The MICs of the commercial smokes to inhibit the growth of foodborne pathogens ranged from 0.5 to 6.0% for E. coli, 0.5 to 8.0% for Salmonella, and 0.38 to 6% for S. aureus. The MIC for each liquid smoke sample was similar in its effect on both E. coli and Salmonella. Solvent-extracted antimicrobials prepared using pecan shells displayed significant differences between their inhibitory concentrations depending on the type of solvent used for extraction. The results indicated that the liquid smoke samples tested in this study could serve as effective natural antimicrobials and that their inhibitory effects depended more on the solvents used for extraction than the wood source.

  8. Selection of pecan shell-based activated carbons for removal of organic and inorganic impurities from water.

    Science.gov (United States)

    Niandou, Mohamed A S; Novak, Jeffrey M; Bansode, Rishipal R; Yu, Jianmei; Rehrah, Djaafar; Ahmedna, Mohamed

    2013-01-01

    Activated carbons are a byproduct from pyrolysis and have value as a purifying agent. The effectiveness of activated carbons is dependent on feedstock selection and pyrolysis conditions that modify their surface properties. Therefore, pecan shell-based activated carbons (PSACs) were prepared by soaking shells in 50% (v/v) HPO or 25 to 50% of KOH-NaHCO followed by pyrolysis at 400 to 700°C under a N atmosphere. Physically activated PSACs were produced by pyrolysis at 700°C under N followed by activation with steam or CO at 700 to 900°C. Physicochemical, surface, and adsorption properties of the PSACs were compared with two commercially available activated carbons. The average mass yield of PSACs with respect to the initial mass of the biomass was about 20 and 34% for physically activated and chemically activated carbons, respectively. Acid-activated carbons exhibited higher surface area, higher bulk density, and lower ash content compared with steam- or CO-activated carbons and the two commercial products. Base activation led to the development of biochar with moderate to high surface area with surface charges suitable for adsorption of anionic species. Regardless of the activation method, PSACs had high total surface area ranging from 400 to 1000 m g, better pore size distribution, and more surface charges than commercial samples. Our results also showed that PSACs were effective in removing inorganic contaminants such as Cu and NO as well as organic contaminants such as atrazine and metolachlor. This study showed that pyrolysis conditions and activation had a large influence on the PSAC's surface characteristics, which can limit its effectiveness as a custom sorbent for targeted water contaminants. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  9. Aqueous extract from pecan nut [Carya illinoinensis (Wangenh) C. Koch] shell show activity against breast cancer cell line MCF-7 and Ehrlich ascites tumor in Balb-C mice.

    Science.gov (United States)

    Hilbig, Josiane; Policarpi, Priscila de Britto; Grinevicius, Valdelúcia Maria Alves de Souza; Mota, Nádia Sandrine Ramos Santos; Toaldo, Isabela Maia; Luiz, Marilde Terezinha Bordignon; Pedrosa, Rozangela Curi; Block, Jane Mara

    2018-01-30

    In Brazil many health disorders are treated with the consumption of different varieties of tea. Shell extracts of pecan nut (Carya illinoinensis), which have significant amounts of phenolic compounds in their composition, are popularly taken as tea to prevent diverse pathologies. Phenolic compounds from pecan nut shell extract have been associated with diverse biological effects but the effect on tumor cells has not been reported yet. The aim of the current work was to evaluate the relationship between DNA fragmentation, cell cycle arrest and apoptosis induced by pecan nut shell extract and its antitumor activity. Cytotoxicity, proliferation, cell death and cell cycle were evaluated in MCF-7 cells by MTT, colony assay, differential coloring and flow cytometry assays, respectively. DNA damage effects were evaluated through intercalation into CT-DNA and plasmid DNA cleavage. Tumor growth inhibition, survival time increase, apoptosis and cell cycle arrest were assessed in Ehrlich ascites tumor in Balb/C mice. The cytotoxic effect of pecan nut shell extracts, the induction of cell death by apoptosis and also the cell cycle arrest in MCF-7 cells have been demonstrated. The survival time in mice with Ehrlich ascites tumor increased by 67%. DNA damage was observed in the CT-DNA, plasmid DNA and comet assays. The mechanism involved in the antitumor effect of pecan nut shell extracts may be related to the activation of key proteins involved in apoptosis cell death (Bcl-XL, Bax and p53) and on the cell cycle regulation (cyclin A, cyclin B and CDK2). These results were attributed to the phenolic profile of the extract, which presented compounds such as gallic, 4-hydroxybenzoic, chlorogenic, vanillic, caffeic and ellagic acid, and catechin, epicatechin, epigallocatechin and epicatechin gallate. The results indicated that pecan nut shell extracts are effective against tumor cells growth and may be considered as an alternative to the treatment of cancer. Copyright © 2017

  10. Evaluation of acute and subacute toxicity and mutagenic activity of the aqueous extract of pecan shells [Carya illinoinensis (Wangenh.) K. Koch].

    Science.gov (United States)

    Porto, Luiz Carlos Santos; da Silva, Juliana; Ferraz, Alexandre de Barros Falcão; Corrêa, Dione Silva; dos Santos, Marcela Silva; Porto, Caroline Dalla Lana; Picada, Jaqueline Nascimento

    2013-09-01

    The infusion of pecan shells has been used to prevent and control hypercholesterolemia, diabetes and toxicological diseases. The aim of the present study was to evaluate toxicity and mutagenic effects of pecan shells aqueous extract (PSAE). Wistar rats were treated with a single dose of 300 or 2000 mg/kg of PSAE in the acute toxicity test. For the subacute test, the animals received 10 or 100 mg/kg of PSAE for 28 days. The mutagenicity was evaluated using Salmonella/microsome assay in TA1535, TA1537, TA98, TA100 and TA102 S. typhimurium strains in the presence and absence of metabolic activation (S9 mix) and micronucleus test in bone marrow. HPLC analyses indicated the presence of tannins, flavonoids, gallic and ellagic acids. Except for triglycerides, all treated groups presented normal hematological and biochemical parameters. Lower levels of triglycerides and weight loss were observed in the 100 mg/kg group. Mutagenic activities were not detected in S. typhimurium strains and by the micronucleus test. Based on these results, PSAE was not able to induce chromosomal or point mutations, under the conditions tested. The 100mg/kg dose showed significant antihyperlipidemic action, with no severe toxic effects. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Testing For Seasonal Cointegration and Error Correction: The U.S. Pecan Price-Inventory Relationship

    OpenAIRE

    Ibrahim, Mohammed; Florkowski, Wojciech J.

    2005-01-01

    Using time series data we examine behavior of pecan prices and inventories at zero and seasonal frequencies, given results of seasonal cointegration tests. Both, seasonally unadjusted and adjusted quarterly data are used (1991-2002). Results suggest that, first, shelled and total pecan inventories and shelled pecan prices have common unit roots at both the non-seasonal and seasonal frequencies; second, there is no long run equilibrium between pecan prices and shelled or total inventories when...

  12. Antinociceptive and antiedematogenic effect of pecan (Carya illinoensis) nut shell extract in mice: a possible beneficial use for a by-product of the nut industry.

    Science.gov (United States)

    Trevisan, Gabriela; Rossato, Mateus F; Hoffmeister, Carin; Müller, Liz G; Pase, Camila; Córdova, Marina M; Rosa, Fernanda; Tonello, Raquel; Hausen, Bruna S; Boligon, Aline A; Moresco, Rafael N; Athayde, Margareth L; Burguer, Marilise E; Santos, Adair R; Ferreira, Juliano

    2014-01-27

    Abstract Background: Interest in pecan (Carya illinoensis) nut shells, a by-product of the nut industry, has increased due to its anti-inflammatory and antioxidant activities. The goal of this study was to evaluate the antinociceptive and antiedematogenic activity and the mechanisms of the pecan shell aqueous extract (AE). Methods: First, we performed fingerprinting of C. illinoensis AE. The antinociceptive and antiedematogenic effects of AE intragastric (i.g.) administration in mice (male Swiss mice 20-30 g) were evaluated using the acetic acid test or after subcutaneous (s.c.) paw injection of diverse transient receptor potential ankyrin 1 (TRPA1) agonists, including hydrogen peroxide (H2O2), allyl isothiocyanate, or cinnamaldehyde. We also observed AE antinociceptive and antiedematogenic effects after carrageenan s.c. paw injection and measured H2O2 production. Moreover, we observed the development of adverse effects after AE i.g. treatment. Results: The high-performance liquid chromatography fingerprinting of AE showed the presence of rutin. AE or rutin i.g. treatment produced antinociception in the acetic acid test and reduced the nociception and edema mediated by H2O2 s.c. hind paw injection or nociception induced by other TRPA1 agonists. Moreover, AE or rutin reduced the hyperalgesia, edema, and H2O2 production induced by carrageenan s.c. paw injection. No motor, gastric, or toxicological alterations were observed after AE administration. Conclusions: Collectively, the present results show that AE and its constituent rutin produced antinociceptive and antiedematogenic action in models of acute and persistent inflammatory nociception and it seems to be related to the inhibition of TRPA1 receptor activation.

  13. Determining host suitability of pecan for stored-product insects.

    Science.gov (United States)

    Shufran, A A; Mulder, P G; Payton, M E; Shufran, K A

    2013-04-01

    A no-choice test was performed to determine survival and reproductive capacity of stored-product insect pests on pecan, Carya illinoensis (Wangenheim) Koch. Insects used were Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae); sawtoothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Cucujidae); red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae); lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae); and rusty grain beetle, Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae). Fifty adults of each beetle species or 10 reproductive pairs of P. interpunctella adults were placed in 0.5-liter containers with either whole-shell pecans, cracked-shell pecans, randomly selected in-shell pecans, pecan nutmeats, cracked wheat, or glass beads and held at 28 degrees C, 60-70% relative humidity, and 16:8 (L:D) photoperiod for 2, 4, 6, and 8 wk. Four replications of each insect-diet-interval combination were performed. Larvae of P. interpunctella, O. surinamensis, T. castaneum, C. ferrugineus, and adult P. interpunctella and O. surinamensis developed on cracked and nutmeat pecan diets. R. dominica did not complete reproduction on pecans. Knowledge that these pests can reproduce on stored pecan will assist pecan growers, accumulators, and storage facilities in preventing insect outbreaks on their product.

  14. Oxidative stress and anxiety-like symptoms related to withdrawal of passive cigarette smoke in mice: beneficial effects of pecan nut shells extract, a by-product of the nut industry.

    Science.gov (United States)

    Reckziegel, P; Boufleur, N; Barcelos, R C S; Benvegnú, D M; Pase, C S; Muller, L G; Teixeira, A M; Zanella, R; Prado, A C P; Fett, R; Block, J M; Burger, M E

    2011-09-01

    The present study evaluated the role of pecan nut (Carya illinoensis) shells aqueous extract (AE) against oxidative damage induced by cigarette smoke exposure (CSE) and behavioral parameters of smoking withdrawal. Mice were passively exposed to cigarette smoke for 3 weeks (6, 10, and 14 cigarettes/day) and orally treated with AE (25 g/L). CSE induced lipid peroxidation in brain and red blood cells (RBC), increased catalase (CAT) activity in RBC, and decreased plasma ascorbic acid levels. AE prevented oxidative damage and increased antioxidant defenses of mice exposed to cigarette smoke. In addition, AE reduced the locomotor activity and anxiety symptoms induced by smoking withdrawal, and these behavioral parameters showed a positive correlation with RBC lipid peroxidation. Our results showed the beneficial effects of this by-product of the pecan industry, indicating its usefulness in smoking cessation. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Double Shell Tank (DST) Process Waste Sampling Subsystem Definition Report

    International Nuclear Information System (INIS)

    RASMUSSEN, J.H.

    2000-01-01

    This report defines the Double-Shell Tank (DST) Process Waste Sampling Subsystem (PWSS). This subsystem definition report fully describes and identifies the system boundaries of the PWSS. This definition provides a basis for developing functional, performance, and test requirements (i.e., subsystem specification), as necessary, for the PWSS. The resultant PWSS specification will include the sampling requirements to support the transfer of waste from the DSTs to the Privatization Contractor during Phase 1 of Waste Feed Delivery

  16. Pecan cultivation: general aspects

    Directory of Open Access Journals (Sweden)

    Diniz Fronza

    2018-02-01

    Full Text Available ABSTRACT: Given the increasing investment in the pecan production in southern Brazil, it becomes necessary researches, assisting in solve problems and proposition of technical and methodology to enhance this production chain. Thus, the present review aimed to survey the existing information about the culture, both on the world and the Brazilian scene. Issues related to botany, climate and soil requirements, alignment and planting density, cultivars, pests and diseases, among other technical aspects of this culture will be addressed. Pecan nut presents nutraceutical properties that are beneficial to human health, which has increased its demand from consumers. However, there are few research results with pecan nut in Brazil and there are many gaps in scientific knowledge about this culture, especially as regards the management of pests and diseases control, irrigation and nutrition, in Brazilian conditions.

  17. Ultrasonic-assisted extraction combined with sample preparation and analysis using LC-ESI-MS/MS allowed the identification of 24 new phenolic compounds in pecan nut shell [Carya illinoinensis (Wangenh) C. Koch] extracts.

    Science.gov (United States)

    Hilbig, Josiane; Alves, Victor Rodrigues; Müller, Carmen Maria Olivera; Micke, Gustavo Amadeu; Vitali, Luciano; Pedrosa, Rozangela Curi; Block, Jane Mara

    2018-04-01

    Ultrasonic-assisted extraction combined with statistical tools (factorial design, response surface methodology and kinetics) were used to evaluate the effects of the experimental conditions of temperature, solid-to-solvent ratio, ethanol concentration and time for the extraction of the total phenolic content from pecan nut shells. The optimal conditions for the aqueous and hydroalcoholic extract (with 20% v/v of ethanol) were 60 and 80 °C; solid to solvent ratio of 30 mL·g -1 (for both) and extraction time of 35 and 25 min, respectively. Using these optimize extraction conditions, 426 and 582 mg GAE·g -1 of phenolic compounds, from the aqueous and hydroalcoholic phases respectively, were obtained. In addition, the analysis of the phenolic compounds using the LC-ESI-MS/MS system allowed the identification of 29 phenolic compounds, 24 of which had not been reported in literature for this raw material yet. Copyright © 2018. Published by Elsevier Ltd.

  18. Is the Texas Pecan Checkoff Program Working?

    OpenAIRE

    Moore, Eli D.; Williams, Gary W.

    2008-01-01

    The Texas Pecan Board was established in 1998 to administer the Texas Pecan Checkoff Program and is financed through a one-half cent per pound assessment on grower pecan sales. The Board spends the assessment collections on a variety of advertising campaigns in an attempt to expand demand for Texas pecans, both improved and native varieties, and increase the welfare of Texas pecan growers. This study presents an evaluation of the economic effectiveness of the Texas Pecan Checkoff Program in e...

  19. [Allergic responses to date palm and pecan pollen in Israel].

    Science.gov (United States)

    Waisel, Y; Keynan, N; Gil, T; Tayar, D; Bezerano, A; Goldberg, A; Geller-Bernstein, C; Dolev, Z; Tamir, R; Levy, I

    1994-03-15

    Date palm (Phoenix dactylifera) and pecan (Carya illinoensis) trees are commonly planted in Israel for fruit, for shade, or as ornamental plants. Pollen grains of both species are allergenic; however, the extent of exposure to such pollen and the incidence of allergic response have not been studied here. We therefore investigated skin-test responses to pollen extracts of 12 varieties of palm and 9 of pecan in 705 allergic patients living in 3 cities and 19 rural settlements. Sensitivity to the pollen extracts of both species was much higher among residents of rural than of urban communities. Moreover, there was a definite relationship between the abundance of these trees in a region and the incidence of skin responders to their pollen. Sensitivity was frequent in settlements rich in these 2 species, such as those with nearby commercial date or pecan plantations. In general, sensitivity to date pollen extracts was lower than to pecan. However, differences in skin responses to pollen extracts of various clones were substantiated. Air sampling revealed that pollen pollution decreased considerably with distance from the trees. At approximately 100 m from a source concentrations of airborne pollen were low. Since planting of male palm and pecan trees in population centers would increase pollen pollution, it should be avoided.

  20. Use of lignocellulosic wastes of pecan (Carya illinoinensis) in the cultivation of Ganoderma lucidum.

    Science.gov (United States)

    Ozcariz-Fermoselle, María Virginia; Fraile-Fabero, Raúl; Girbés-Juan, Tomás; Arce-Cervantes, Oscar; Oria de Rueda-Salgueiro, Juan Andrés; Azul, Anabela Marisa

    The wastes of pecan nut (Carya illinoinensis (Wangenh.) K. Koch) production are increasing worldwide and have high concentrations of tannins and phenols. To study the biodegradation of lignocellulosic wastes of pecan used as solid substrate for the cultivation of the white-rot fungus Ganoderma lucidum (Curtis) P. Karst. Six formulations of pecan wastes were used as solid substrate: pecan shells (PS100), pecan pericarp (PP100), pecan wood-chips (PB100), and the combinations PS50+PP50, PB50+PS50 and PB50+PP50. The substrates were inoculated with a wild strain of G. lucidum collected in the Iberian Peninsula. The biodegradation capability of G. lucidum was estimated by using the mycelial growth rate, the biological efficiency, the production and the dry biological efficiency. Notably, all solid substrates were suitable for G. lucidum growth and mushroom yield. The best performance in mushroom yield was obtained with PB100 (55.4% BE), followed by PB50+PP50 (31.7% BE) and PB50+PS50 (25.4% BE). The mushroom yield in the substrates containing pecan wood-chips (PB) was significantly higher. Our study is leading the way in attempting the cultivation of G. lucidum on lignocellulosic pecan waste. These results show an environmentally friendly alternative that increases the benefits for the global pecan industry, especially in rural areas, and transforms biomass into mushrooms with nutraceutical properties and biotechnological applications. Copyright © 2018 Asociación Española de Micología. Publicado por Elsevier España, S.L.U. All rights reserved.

  1. Double Shell Tank (DST) Monitor and Control Subsystem Definition Report

    International Nuclear Information System (INIS)

    BAFUS, R.R.

    2000-01-01

    The system description of the Double-Shell Tank (DST) Monitor and Control Subsystem establishes the system boundaries and describes the interface of the DST Monitor and Control Subsystem with new and existing systems that are required to accomplish the Waste Feed Delivery (WFD) mission

  2. Stovetop Earth Pecan Pie

    Science.gov (United States)

    Robin, C. M.

    2005-12-01

    Many fluid mechanical experiments with direct applications to Earth Science are performed with sugary syrups using conceptually straightforward procedures. Corn syrup has indeed proven to be a godsend for those studying convection and related non-linear phenomena. In addition, however, it gives experimentalists a deep physical intuition for the interior workings of hot planets. The basic concepts behind plate tectonics and mantle convection are not difficult; indeed, although they may not be aware of it, most students probably have a basic intuitive understanding of fluid mechanics gained in their daily life. However, the large size and long time scale of geophysical processes may be quite intimidating to young students. Even a simple geophysical experiment requires a complicated array of coolers, heaters and measuring and recording equipment. It is of interest to introduce students to the geodynamical concepts that can be visualized in a high-tech lab using familiar processes and equipment. Using a homemade apparatus and grocery store supplies, I propose using a 'Stove-top Earth pecan pie' to introduce simple geodynamic concepts to middle- and high-school students. The initially cold syrup heats up and the pecans begin to float (continent formation), the syrup begins to convect (mantle convection), and convection slows down after the heat is removed (secular cooling). Even Wilson cycles can be simulated by moving the pan to one side or the other of the stovetop or heating element. The activity formally introduces students to convection and its application to the earth, and makes them think about plate motion, heat transfer, scaling, and experimental procedures. As an added bonus, they can eat their experiments after recess!

  3. Particle film affects black pecan aphid (Homoptera: Aphididae) on pecan.

    Science.gov (United States)

    Cottrell, Ted E; Wood, Bruce W; Reilly, Charles C

    2002-08-01

    Three species of aphids attack pecan foliage, Carya illinoensis (Wang.) K. Koch, and cause economic damage. We tested a kaolin-based particle film against one of these aphid species, black pecan aphid, Melanocallis caryaefoliae (Davis). Effect of particle film on host selection, adult mortality, and production of nymphs by M. caryaefoliae was tested on seedling pecans in the laboratory. Fewer M. caryaefoliae adults selected treated foliage compared with untreated foliage. A higher percentage of adults that did select treated foliage were recovered from upper leaf surfaces compared with the percentage of adults recovered from upper leaf surfaces of untreated leaves. Observations with a microscope revealed an accumulation of particle film on aphid body parts, especially on tarsi, and strongly suggests that aphid mobility was restricted. Adult mortality was higher on treated foliage and led to an overall decrease in production of nymphs on those seedlings. In addition, we measured spectral properties of treated seedling pecan foliage. Light reflectance by treated foliage was increased and absorptance decreased compared with control foliage whereas transmittance of light through control and particle film-treated leaves was similar. We did not detect any phytotoxic effect on pecan due to application of particle film.

  4. New bacterial products for control of pecan pests

    Science.gov (United States)

    Pecans are economically the most important native nut crop in the USA. Among the major concerns are the pecan weevil (Curculio caryae), pecan aphids, and diseases such as pecan scab, Venturia effusa. These pests are generally controlled with broad spectrum chemicals. The chemical pesticides can be...

  5. Profitability of Irrigated Improved Pecan Orchards in the Southern Plains

    OpenAIRE

    Springer, Job D.; Swinford, Wyatt; Rohla, Charles

    2011-01-01

    The objective was to determine if an irrigated improved pecan orchard is economical relative to agronomic systems commonly implemented by producers that have access to irrigation. Results show that the improved pecan orchard is more profitable than competitive enterprises after a twenty year time frame, but is sensitive to pecan price, pecan yield and attitude toward risk.

  6. PECAN PRODUCTION AND PRICE TRENDS 1979-1995

    OpenAIRE

    Shafer, Carl E.

    1996-01-01

    Pecan production, stocks, trade and prices are described. Data on tree nuts believed to compete with pecans are also presented. Pecan production and prices became more volatile in the early 1990's. Prices reached exceptionally high levels during five of the six years 1990-1995. US pecan imports have increased significantly since the mid-1980's and clearly exceed exports. Production, cold storage stocks, and inflation explained most of the year-to-year changes in season average pecan price lev...

  7. Nonnegative definite EAP and ODF estimation via a unified multi-shell HARDI reconstruction.

    Science.gov (United States)

    Cheng, Jian; Jiang, Tianzi; Deriche, Rachid

    2012-01-01

    In High Angular Resolution Diffusion Imaging (HARDI), Orientation Distribution Function (ODF) and Ensemble Average Propagator (EAP) are two important Probability Density Functions (PDFs) which reflect the water diffusion and fiber orientations. Spherical Polar Fourier Imaging (SPFI) is a recent model-free multi-shell HARDI method which estimates both EAP and ODF from the diffusion signals with multiple b values. As physical PDFs, ODFs and EAPs are nonnegative definite respectively in their domains S2 and R3. However, existing ODF/EAP estimation methods like SPFI seldom consider this natural constraint. Although some works considered the nonnegative constraint on the given discrete samples of ODF/EAP, the estimated ODF/EAP is not guaranteed to be nonnegative definite in the whole continuous domain. The Riemannian framework for ODFs and EAPs has been proposed via the square root parameterization based on pre-estimated ODFs and EAPs by other methods like SPFI. However, there is no work on how to estimate the square root of ODF/EAP called as the wavefuntion directly from diffusion signals. In this paper, based on the Riemannian framework for ODFs/EAPs and Spherical Polar Fourier (SPF) basis representation, we propose a unified model-free multi-shell HARDI method, named as Square Root Parameterized Estimation (SRPE), to simultaneously estimate both the wavefunction of EAPs and the nonnegative definite ODFs and EAPs from diffusion signals. The experiments on synthetic data and real data showed SRPE is more robust to noise and has better EAP reconstruction than SPFI, especially for EAP profiles at large radius.

  8. Phenolic content and anti-hyperglycemic activity of pecan cultivars from Egypt.

    Science.gov (United States)

    El Hawary, Seham S; Saad, Soumaya; El Halawany, Ali Mahmoud; Ali, Zeinab Y; El Bishbishy, Mahitab

    2016-01-01

    Pecans are commonly used nuts with important health benefits such as anti-hyperglycemic and anti-hyperlipidemic effects. A comparative investigation of the antihyperglycemic and total phenolic content of the leaves and shells of four pecan cultivars growing in Egypt was carried out. The selected cultivars (cv.) were Carya illinoinensis Wangneh. K. Koch. cv. Wichita, cv. WesternSchely, cv. Cherokee, and cv. Sioux family Juglandaceae. Total phenolic and flavonoid contents of the leaves and shells of pecan cultivars were carried out using Folin-Ciocalteu's and aluminum chloride assays, respectively. Moreover, HPLC profiling of phenolic and flavonoid contents was carried out using RP-HPLC-UV. In addition, in vivo anti-hyperglycemic activity of the ethanolic extracts (125 mg/kg bw, p.o.) of C. illinoinensis cultivars was carried out using streptozotocin (STZ)-induced diabetes in Sprague-Dawley rats for 4 weeks. Phenolic contents were higher in shells than leaves in all studied cultivars, while flavonoids were higher in leaves. Leaves and shells of cv. Sioux showed the highest phenolics (251.7 µg gallic acid equivalent (GAE)/g), and flavonoid contents (103.27 µg rutin equivalent (RE)/g and 210.67 µg quercetin equivalent (QE)/g), respectively. The HPLC profiling of C. illinoinensis cultivars resulted in the identification of eight flavonoids (five of these compounds are identified for the first time from pecan), and 15 phenolic acids (six are identified for the first time from pecan). Leaves of cv. Sioux revealed the most potent decrease in blood glucose and glycated hemoglobin (HbA1c%) (194.9 mg/dl and 6.52%, respectively), among other tested cultivars. Moreover, leaves of cv. Sioux significantly elevated serum total antioxidant capacity (TAC) and reduced glutathione (GSH) (0.33 mMol/l and 30.68 mg/dl, respectively), and significantly suppressed the markers of both lipid peroxidation (malondialdehyde, MDA) and protein oxidation (protein carbonyl, PC

  9. Advances in organic insect pest management in pecan

    Science.gov (United States)

    Pecans are economically the most important native nut crop in the USA. The market for organic pecans has been growing. However, in the Southeastern USA, there are a number of insect pests and plant diseases that challenge the ability of growers to produce organic pecans in an economically sound ma...

  10. Radar Rainfall Statistics During PECAN

    Science.gov (United States)

    Romatschke, U.; Weckwerth, T.

    2017-12-01

    The Plains Elevated Convection At Night (PECAN) field campaign, based in Kansas, USA, took place from May to July 2015. It was designed to understand the causes and improve predictions of the central US nocturnal precipitation maximum. Over 100 instruments were utilized to sample the pre-convective and convective conditions within and around unorganized storms and Mesoscale Convective Systems (MCSs). We analyze quantitative precipitation estimates (QPEs) derived from a dense network of NEXRADs which, combined with S-Pol, cover an area extending from the eastern side of the Rocky Mountains over the Central Great Plains. As expected, precipitation maxima occurred during the afternoon and evening over the eastern Rocky Mountains and during the night over the plains. The precipitation over the mountains is almost exclusively associated with smaller scale storms which are triggered by solar heating over the elevated terrain. The mountain triggered storms quickly grow and merge to the size of MCSs and are then advected east over the plains. Storms are also initiated over the plains but at much lower frequency than over the mountains. The diurnal cycle of plain initiation is much less pronounced with a broad peak in the afternoon and evening but also significant convection initiation during the night. The nocturnal precipitation over the plains is primarily associated with the MCSs advected from the mountains which merge with the storms triggered over the plains. Some precipitation over the plains is generated by pristine storms triggered over the plains but their precipitation contribution is mostly secondary compared to the merged systems.

  11. New insight into pecan boron nutrition

    Science.gov (United States)

    Alternate bearing by individual pecan [Carya illinoinensis (Wangenh.) K. Koch] trees is problematic for nut producers and processors. There are many unknowns regarding alternate bearing physiology, such as the relationship between boron and fruit set, nutmeat quality, and kernel maladies. Evidence...

  12. DEMAND AND QUALITY UNCERTAINTY IN PECAN PURCHASING DECISIONS

    OpenAIRE

    Park, Timothy A.; Florkowski, Wojciech J.

    1996-01-01

    A generalized Heckman model of purchase decisions incorporating perceived consumer quality attributes, ease of purchase, and familiarity with marketing outlets as factors influencing pecan purchases is estimated. Marketing efforts that encourage consumers to expand expenditures on nut products increase both the probability of pecan purchases and the amount purchased. Consumers who use all types of nuts in a wider variety of foods tend to purchase pecans more frequently. A diverse set of marke...

  13. Control of Pecan Weevil With Microbial Biopesticides.

    Science.gov (United States)

    Shapiro-Ilan, David I; Cottrell, Ted E; Bock, Clive; Mai, Kim; Boykin, Debbie; Wells, Lenny; Hudson, William G; Mizell, Russell F

    2017-12-08

    The pecan weevil, Curculio caryae (Horn) (Coleoptera: Curculionidae), is a key pest of pecans Carya illinoinensis ([Wangenh.] K. Koch) (Fagales: Juglandaceae). Control recommendations rely on broad spectrum chemical insecticides. Due to regulatory and environmental concerns, effective alternatives for C. caryae control must be sought for pecan production in conventional and organic systems. We explored the use of microbial biopesticides for control of C. caryae in Georgia pecan orchards. Three experiments were conducted. The first investigated an integrated microbial control approach in an organic system at two locations. Three microbial agents, Grandevo (based on byproducts of the bacterium Chromobacterium subtsugae Martin, Gundersen-Rindal, Blackburn & Buyer), the entomopathogenic nematode Steinernema carpocapsae (Weiser), and entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin, were applied to each treatment plot (0.6 ha) at different times during the season. A second experiment compared the effects of S. carpocapsae and B. bassiana applied as single treatments relative to application of both agents (at different times); survival of C. caryae was assessed approximately 11 mo after larvae were added to pots sunk in an organic pecan orchard. In a conventional orchard (with 1.0 ha plots), the third experiment compared Grandevo applications to a commonly used regime of chemical insecticides (carbaryl alternated with a pyrethroid). All experiments were repeated in consecutive years. The combined pest management tactic (experiment 1) reduced C. caryae infestation relative to non-treated control plots in both locations in 2014 and one of the two locations in 2015 (the other location had less than 1% infestation). In experiment 2, no differences among combined microbial treatments, single-applied microbial treatments or different numbers of application were observed, yet all microbial treatments reduced C. caryae survival relative to the control. In the third

  14. Chlorotic feeding injury by the black pecan aphid (hemiptera: aphididae) to pecan foliage promotes aphid settling and nymphal development.

    Science.gov (United States)

    Cottrell, Ted E; Wood, Bruce W; Ni, Xinzhi

    2009-04-01

    The nature of the interaction between the black pecan aphid, Melanocallis caryaefoliae (Davis) (Hemiptera: Aphididae), and the chlorosis it causes to foliage of its pecan [Carya illinoinensis (Wangenh.) K. Koch)] host is poorly understood. Laboratory experiments were conducted on the settling behavior of the black pecan aphid, when provided chlorotic pecan leaf discs resulting from previous black pecan aphid feeding and nonchlorotic leaf discs, under a normal photoperiod and constant dark. Additionally, aphid development from the first instar to the adult stage was examined when nymphs were either allowed to feed on the same leaf disc or moved daily to a new, nondamaged, same age leaf disc. After 24 h, a significantly higher percentage of black pecan aphids settled on chlorotic than on nonchlorotic leaf discs, regardless of photoperiod. When starting from the first instar, nymphs that were prevented from inducing leaf chlorosis by moving daily to new, same-age leaf discs took approximately 5 d longer to complete development, had a shorter body length, and had higher mortality than when aphids remained on the same leaf disc. These results show that black pecan aphid-induced leaf chlorosis plays an important role in the interaction of the black pecan aphid with its pecan host.

  15. The rare-earth metallome of pecan and other Carya

    Science.gov (United States)

    The nutritional physiology of pecan [Carya illinoinensis (Wangenh.) K. Koch] and other Carya species remains to be fully understood; thus, presenting a substantial knowledge gap in the horticulture of pecan and similar species. There is an especial lack of knowledge regarding the metabolic, ecophys...

  16. Mycorrhizal inoculation of pecan seedlings with some marketable truffles

    Directory of Open Access Journals (Sweden)

    Gian M. Benucci

    2013-12-01

    Full Text Available Pecan is the common name of Carya illinoinensis (Wangenh. K. Koch, an ectomycorrhizal tree native to North America, also frequently known as hickory. Mycorrhizal inoculations of pecan seedlings with: Tuber aestivum Vittad., T. borchii Vittad., T. indicum Cooke & Massee, and T. lyonii Butters are described and discussed.

  17. Genetic recombination in Venturia effusa, causal agent of pecan scab

    Science.gov (United States)

    Venturia effusa causes pecan scab, the most prevalent disease of pecan in the southeastern USA. Mating type idiomorphs were recently characterized and the sexual stage was subsequently produced in vitro. To investigate sexual reproduction and recombination of traits in V. effusa, select isolates wer...

  18. Scab susceptibility of a provenance collection of pecan

    Science.gov (United States)

    Scab (caused by Fusicladium effusum) is the most economically destructive disease of pecan in the Southeast US. Epidemics are favored by rainfall and high humidity. A provenance collection of ~950 pecan trees from 19 locations representing the native range of the species is located in Byron, Georgia...

  19. Pecan scab – A retrospective, current status and future management

    Science.gov (United States)

    Pecan scab (caused by Fusicladium effusum) is the most economically destructive disease of pecan in the Southeast US. Wet, humid conditions typical of the Southeast are known to provide conditions conducive to epidemics. The history of the disease is described since its first discovery in the US. Me...

  20. Characterization of microsatellites in Fusicladium effusum, cause of pecan scab

    Science.gov (United States)

    Pecan scab, caused by the plant pathogenic fungus Fusicladium effusum, is the most destructive disease of pecan. Little is known of the population genetic diversity of this pathogen. In this study, microsatellites were mined from the F. effusum genome, and flanking primers were subsequently designed...

  1. Draft genome sequence of Fusicladium effusum, cause of pecan scab

    Science.gov (United States)

    Pecan scab, caused by the plant pathogenic fungus Fusicladium effusum, is the most destructive disease of pecan, an important specialty crop cultivated in several regions of the world. At this time, no other members of the family Venturiaceae (in which the pathogen resides) have been reported sequen...

  2. Vertical distribution of scab in large pecan trees

    Science.gov (United States)

    Pecan scab (caused by Fusicladium effusum) is a destructive disease of pecan (Carya illinoensis) grown in humid environments, such as the southeastern US. The disease can cause severe yield loss, and although much is known about the processes of dispersal and infection, there is no information on di...

  3. Protein energetic conformational analysis from NMR chemical shifts (PECAN) and its use in determining secondary structural elements

    Energy Technology Data Exchange (ETDEWEB)

    Eghbalnia, Hamid R.; Wang Liya; Bahrami, Arash [National Magnetic Resonance Facility at Madison, Biochemistry Department (United States); Assadi, Amir [University of Wisconsin-Madison, Mathematics Department (United States); Markley, John L. [National Magnetic Resonance Facility at Madison, Biochemistry Department (United States)], E-mail: eghbalni@nmrfam.wisc.edu

    2005-05-15

    We present an energy model that combines information from the amino acid sequence of a protein and available NMR chemical shifts for the purposes of identifying low energy conformations and determining elements of secondary structure. The model ('PECAN', Protein Energetic Conformational Analysis from NMR chemical shifts) optimizes a combination of sequence information and residue-specific statistical energy function to yield energetic descriptions most favorable to predicting secondary structure. Compared to prior methods for secondary structure determination, PECAN provides increased accuracy and range, particularly in regions of extended structure. Moreover, PECAN uses the energetics to identify residues located at the boundaries between regions of predicted secondary structure that may not fit the stringent secondary structure class definitions. The energy model offers insights into the local energetic patterns that underlie conformational preferences. For example, it shows that the information content for defining secondary structure is localized about a residue and reaches a maximum when two residues on either side are considered. The current release of the PECAN software determines the well-defined regions of secondary structure in novel proteins with assigned chemical shifts with an overall accuracy of 90%, which is close to the practical limit of achievable accuracy in classifying the states.

  4. Protein energetic conformational analysis from NMR chemical shifts (PECAN) and its use in determining secondary structural elements

    International Nuclear Information System (INIS)

    Eghbalnia, Hamid R.; Wang Liya; Bahrami, Arash; Assadi, Amir; Markley, John L.

    2005-01-01

    We present an energy model that combines information from the amino acid sequence of a protein and available NMR chemical shifts for the purposes of identifying low energy conformations and determining elements of secondary structure. The model ('PECAN', Protein Energetic Conformational Analysis from NMR chemical shifts) optimizes a combination of sequence information and residue-specific statistical energy function to yield energetic descriptions most favorable to predicting secondary structure. Compared to prior methods for secondary structure determination, PECAN provides increased accuracy and range, particularly in regions of extended structure. Moreover, PECAN uses the energetics to identify residues located at the boundaries between regions of predicted secondary structure that may not fit the stringent secondary structure class definitions. The energy model offers insights into the local energetic patterns that underlie conformational preferences. For example, it shows that the information content for defining secondary structure is localized about a residue and reaches a maximum when two residues on either side are considered. The current release of the PECAN software determines the well-defined regions of secondary structure in novel proteins with assigned chemical shifts with an overall accuracy of 90%, which is close to the practical limit of achievable accuracy in classifying the states

  5. A Robust Recognition System for Pecan Weevil using Artificial Neural Networks

    OpenAIRE

    Saleh Mufleh Al-Saqer

    2012-01-01

    Problem statement: Pecan Weevil is a widely found pest among pecan trees and these pests are known to cause significant damage to the pecan trees resulting in enormous annual losses to pecan growers. Traditional identification techniques for pecan weevil include traps with pheromones to detect the infestation of these pests. However, these traditional methods require expensive labor hours to set-up the traps and their monitoring. These techniques are also unreliable for early detection of pec...

  6. Fruit and nut weight in pecan trees canopies in relation to the severity of pecan scab at different heights

    Science.gov (United States)

    Fusicladium effusum is the cause of pecan scab, the most destructive disease of pecan in the southeastern US. This study addressed the distribution of scab and measures of yield in relation to sample height in tall trees (14 to 16 m tall) in three experiments in 2010 and 2011 with trees receiving fu...

  7. Establishing axenic cultures from mature pecan embryo explants on media with low water availability.

    Science.gov (United States)

    Obeidy, A A; Smith, M A

    1990-12-01

    Endophytic fungi associated with mature pecan (Carya illinoensis (Wangenh.) C. Koch) nuts prevented successful, contaminant-free in vitro culture of embryo expiants, even after rigorous surface disinfestation of the nuts and careful aseptic shelling. Disinfestation with sodium hypochlorite after shell removal was also unsuccessful, because even dilute concentrations which were ineffective against the fungal contaminants prevented subsequent growth from the embryo. Explanting media with low water availability which would not sustain growth of fungal contaminants, but supported growth from mature pecan embryos, were developed as an alternative disinfestation method. The explanting media were supplemented with 0.9-1.5% agar, and other media components were selectively omitted to test their influence on water availability and fungal growth. Disinfestation of up to 65% of the cultures was accomplished, depending on the medium formulation, compared to 100% loss to contamination on control medium (0.5% agar). A complete medium (containing sucrose, salts, vitamins, 18 μM BAP, and 5 μM IBA) with 1.5% agar provided control of contamination, and encouraged subsequent regeneration from the embryo expiants, which remained free of contaminant growth through subsequent subcultures.

  8. A simple, rapid, cost-effective and sensitive method for detection of Salmonella in environmental and pecan samples.

    Science.gov (United States)

    Dobhal, S; Zhang, G; Rohla, C; Smith, M W; Ma, L M

    2014-10-01

    PCR is widely used in the routine detection of foodborne human pathogens; however, challenges remain in overcoming PCR inhibitors present in some sample matrices. The objective of this study was to develop a simple, sensitive, cost-effective and rapid method for processing large numbers of environmental and pecan samples for Salmonella detection. This study was also aimed at validation of a new protocol for the detection of Salmonella from in-shell pecans. Different DNA template preparation methods, including direct boiling, prespin, multiple washing and commercial DNA extraction kits, were evaluated with pure cultures of Salmonella Typhimurium and with enriched soil, cattle feces and in-shell pecan each spiked individually with Salmonella Typhimurium. PCR detection of Salmonella was conducted using invA and 16S rRNA gene (internal amplification control) specific primers. The effect of amplification facilitators, including bovine serum albumin (BSA), polyvinylpyrrolidone (PVP), polyethylene glycol (PEG) and gelatin on PCR sensitivity, was also evaluated. Conducting a prespin of sample matrices in combination with the addition of 0·4% (w/v) BSA and 1% (w/v) PVP in PCR mix was the simplest, most rapid, cost-effective and sensitive method for PCR detection of Salmonella, with up to 40 CFU Salmonella per reaction detectable in the presence of over 10(9 ) CFU ml(-1) of background micro-organisms from enriched feces soil or pecan samples. The developed method is rapid, cost-effective and sensitive for detection of Salmonella from different matrices. This study provides a method with broad applicability for PCR detection of Salmonella in complex sample matrices. This method has a potential for its application in different research arenas and diagnostic laboratories. © 2014 The Society for Applied Microbiology.

  9. Double-Shell Tank (DST) Maintenance and Recovery Subsystem Definition Report

    International Nuclear Information System (INIS)

    SMITH, E.A.

    2000-01-01

    The description of the Double-Shell Tank (DST) Maintenance and Recovery Subsystem presented in this document was developed to establish its boundaries. The DST Maintenance and Recovery Subsystem consists of new and existing equipment and facilities used to provide tank farm operators logistic support and problem resolution for the DST System during operations. This support will include evaluating equipment status, performing preventive and corrective maintenance, developing work packages, managing spares and consumables, supplying tooling, and training maintenance and operations personnel

  10. Protective effects of a by-product of the pecan nut industry (Carya illinoensis) on the toxicity induced by cyclophosphamide in rats Carya illinoensis protects against cyclophosphamide-induced toxicity.

    Science.gov (United States)

    Benvegnú, D; Barcelos, R C S; Boufleur, N; Reckziegel, P; Pase, C S; Müller, L G; Martins, N M B; Vareli, C; Bürger, M E

    2010-01-01

    This study investigated the antioxidant effects of pecan nut (Carya illinoensis) shell aqueous extract (AE) on toxicity induced by cyclophosphamide (CP) in the heart, kidney, liver, bladder, plasma and erythrocytes of rats. Rats were treated with water or pecan shell AE (5%) ad libitum, replacing drinking water for 37 days up to the end of the experiment. On day 30, half of each group received a single administration of vehicle or CP 200 mg/kg-ip. After 7 days, the organs were removed. Rats treated with CP showed an increase in lipid peroxidation (LP) and decrease in reduced glutathione (GSH) levels in all structures. Catalase (CAT) activity was increased in the heart and decreased in liver and kidney. Besides, CP treatment decreased plasmatic vitamin C (VIT C) levels and induced bladder macroscopical and microscopical damages. In contrast, co-treatment with pecan shell AE prevented the LP development and the GSH depletion in all structures, except in the heart and plasma, respectively. CAT activity in the heart and liver as well as the plasmatic VIT C levels remained unchanged. Finally, AE prevented CP-induced bladder injury. These findings revealed the protective role of pecan shell AE in CP-induced multiple organ toxicity.

  11. First report of pecan bacterial leaf scorch caused by Xylella fastidiosa in pecan (Carya illinoinensis) in Arizona, New Mexico, California, and Texas

    Science.gov (United States)

    Pecan bacterial leaf scorch (PBLS) is a chronic disease that can cause major yield losses in pecan orchards. In the 2015-16 growing seasons, symptoms consistent with PBLS were observed in commercial pecan cultivars in AZ, NM, CA and TX. Symptoms included tan to light brown necrotic lesions, which ...

  12. Identification of pecan scab resistance gene candidates in a pecan provenance collection using a combined bulked segregant analysis and genotyping by sequencing approach

    Science.gov (United States)

    Pecan [Carya illinoinensis (Wangenh.) K. Koch] is an important horticultural crop in the USA worth over $560 million in 2015. Pecan is a diploid species endemic to the Mississippi River Valley. Pecan scab is caused by the fungus Fusicladium effusum and infection causes losses in nut yield and qualit...

  13. Seasonal Abundance of Aphids and Aphidophagous Insects in Pecan

    Directory of Open Access Journals (Sweden)

    Ghulam Abbas

    2012-12-01

    Full Text Available Seasonal occurrence of aphids and aphidophagous insects was monitored for six years (2006–2011 from full leaf expansion in May to leaf fall in October in “Desirable” variety pecan trees that were not treated with insecticides. Aphid outbreaks occurred two times per season, once in the spring and again in the late summer. Yellow pecan and blackmargined aphids exceeded the recommended treatment thresholds one time and black pecan aphids exceeded the recommended treatment levels three times over the six seasons. Increases in aphidophagous insect abundance coincided with aphid outbreaks in five of the six seasons. Among aphidophagous insects Harmonia axyridis and Olla v-nigrum were frequently collected in both the tree canopy and at the ground level, whereas, Coccinella septempunctata, Hippodamia convergens were rarely found in the tree canopy and commonly found at the ground level. Green lacewing abundance was higher in the ground level than in the tree canopy. Brown lacewings were more abundant in the tree canopy than at the ground level. Dolichopodid and syrphid fly abundance, at the ground level increased during peak aphid abundance in the tree canopy. Application of an aqueous solution of fermenting molasses to the pecan foliage during an aphid outbreak significantly increased the abundance of ladybeetles and lacewings and significantly reduced the abundance of yellow pecan, blackmargined and black pecan aphids.

  14. Analysis of pecan cultivars Mahan and Western in East China.

    Science.gov (United States)

    Luo, X; Li, Z; Sun, Z; Wan, X

    2016-09-16

    Pecan (Carya illinoensis) has been introduced to East China for over one hundred years, but its planting is still only occurring at a small scale. The key limiting factor is its low yield. To enhance the yield pecan in East China, two pecan cultivars, Mahan and Western, were examined. Twenty traits describing phasic development, yield, nut quality, and cultural practice were investigated. We found that pecan cultivar Mahan gives a higher yield and nut quality than cultivar Western. We recommend interplanting of cultivar Pawnee to act as a pollinator tree. Appropriate cultivation practices that can be implemented to enhance fruit yield of cultivars Mahan and Western include soil-applied paclobutrazol (PBZ) at certain concentrations, pinching, and supplementary pollination. For example, the addition of 1.25 g/m 2 of PBZ inhibits pecan branch growth and stimulates short bearing branches, which promotes fruit yield. We found that soil-applied PBZ reached optimal performance 82 days after application. A pinching length of 40 cm resulted in a fruit yield increase. In addition, grafting and transplantation may promote male flowering, but delays female flowering. These cultural practices may provide insights that can be used to improve pecan cultivation in East China.

  15. Seasonal Abundance of Aphids and Aphidophagous Insects in Pecan

    Science.gov (United States)

    Dutcher, James D.; Karar, Haider; Abbas, Ghulam

    2012-01-01

    Seasonal occurrence of aphids and aphidophagous insects was monitored for six years (2006–2011) from full leaf expansion in May to leaf fall in October in “Desirable” variety pecan trees that were not treated with insecticides. Aphid outbreaks occurred two times per season, once in the spring and again in the late summer. Yellow pecan and blackmargined aphids exceeded the recommended treatment thresholds one time and black pecan aphids exceeded the recommended treatment levels three times over the six seasons. Increases in aphidophagous insect abundance coincided with aphid outbreaks in five of the six seasons. Among aphidophagous insects Harmonia axyridis and Olla v-nigrum were frequently collected in both the tree canopy and at the ground level, whereas, Coccinella septempunctata, Hippodamia convergens were rarely found in the tree canopy and commonly found at the ground level. Green lacewing abundance was higher in the ground level than in the tree canopy. Brown lacewings were more abundant in the tree canopy than at the ground level. Dolichopodid and syrphid fly abundance, at the ground level increased during peak aphid abundance in the tree canopy. Application of an aqueous solution of fermenting molasses to the pecan foliage during an aphid outbreak significantly increased the abundance of ladybeetles and lacewings and significantly reduced the abundance of yellow pecan, blackmargined and black pecan aphids. PMID:26466738

  16. Changes of oxidase and hydrolase activities in pecan leaves elicited by black pecan aphid (Hemiptera: Aphididae) feeding.

    Science.gov (United States)

    Chen, Yigen; Ni, Xinzhi; Cottrell, Ted E; Wood, Bruce W; Buntin, G David

    2009-06-01

    The black pecan aphid, Melanocallis caryaefoliae (Davis) (Hemiptera: Aphididae), is a foliar feeder of pecan, Carya illinoinensis (Wangenh.) K. Koch (Juglandaceae). The pest causes chlorosis of leaflet lamina, physiological damage to foliage and trees, and commonly limits the profitability of commercial pecan orchard enterprises. However, key aspects of this host-pest interaction are poorly understood. We report here the effects of M. caryaefoliae feeding on the foliar activity of oxidative (i.e., catalase, lipoxygenase [LOX]-1 and 3, and peroxidase) and hydrolytic (i.e., esterase) enzymes in relation to the degree of aphid resistance among pecan varieties. The 2-yr study showed that M. caryaefoliae-infested foliage exhibited elevated peroxidase activity only in susceptible ('Desirable', 'Sumner', and 'Schley'), but not in resistant ('Cape Fear', 'Gloria Grande', and 'Money Maker') genotypes. Susceptible genotypes also exhibited more severe leaf chlorosis in response to M. caryaefoliae feeding than the resistant genotypes; however, the aphid feeding did not influence catalase or esterase activity in all varieties, except the increase of esterase activity in Desirable and Gloria Grande. Melanocallis caryaefoliae feeding also influences activity of two lipoxygenase isozymes, with LOX3 being more frequently induced than LOX1. Foliar LOX3 activity was more frequently induced by M. caryaefoliae feeding in the moderately resistant 'Oconee' and highly resistant Money Maker and Cape Fear than in the susceptible genotypes. Therefore, the elevation of peroxidase is likely to be associated with aphid susceptibility and contributed to the severe leaf chlorosis, whereas the increase of LOX3 activity might be associated with aphid resistance in pecan. These findings contribute to our understanding of the etiology of M. caryaefoliae-elicited leaf chlorosis on pecan foliage. Such information may also be used to develop enzyme markers for identifying black pecan aphid resistance

  17. 78 FR 33690 - Common Crop Insurance Regulations; Pecan Crop Insurance Provisions; Correction

    Science.gov (United States)

    2013-06-05

    ...-0008] RIN 0563-AC35 Common Crop Insurance Regulations; Pecan Crop Insurance Provisions; Correction... FR 13454-13460). The regulation pertains to the insurance of Pecans. DATES: Effective Date: June 5...: [[Page 33691

  18. Determining the Pollinizer for Pecan Cultivars

    Directory of Open Access Journals (Sweden)

    Fereidoon Ajamgard

    2017-05-01

    Full Text Available This study was conducted to determine the best pollinizer for five selected pecan cultivars in southwest of Iran at Safiabad Agricultural Research Center in 2014-2015. The cultivars included: 'GraTex', '10J', 'Wichita 6J', 'GraKing', 'Choctaw' as pollinated cultivars (♀ and 'GraTex', 'Peruque', 'Comanche 4M', '10J', 'Wichita 6J', 'Mohawk', 'Mahan', 'Stuart 2J', '3J', 'Stuart 4J', 'GraKing', 'Choctaw', 'Apache', '6M', 'Wichita 7J' and 'Comanche 5M.' as pollinizer cultivars (♂. In the first step, a pollination chart of cultivars was determined in two years. The pollination chart of cultivars showed that all the cultivars investigated during this study were dichogamous and also protogynous except for the 'Peruque'. ‘GraKing’ had the longest duration of shedding pollen. Pollination chart showed that 'Peruque', ‘GraKing’, and 'Stuart 2J' had flowering overlap with the selected cultivars. Pollen germination test showed that the germination ability was different among the cultivars. It was 45% for 'GraKing' and 35% for 'Peruque', which were both recommended as pollinizers in this study. '6M', 'GraTex' and 'Stuart 4J' cultivars had the highest pollen germination percentage of 65%, 60% and 60%, respectively. The results of controlled pollinationtest showed that different pollen sources had no significant effect on nuts per cluster but self-pollinated all of the cultivars significantly reduced fruit set in first and second years. Based on the present research, pollination in pecan orchard was necessary for adequate yield. Also, 'Peruque', 'GraKing' and 'Stuart 2J' were the best pollinizers for five selected cultivars in southwest of Iran.

  19. Pecan Street Grid Demonstration Program. Final technology performance report

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2015-02-10

    This document represents the final Regional Demonstration Project Technical Performance Report (TPR) for Pecan Street Inc.’s (Pecan Street) Smart Grid Demonstration Program, DE-OE-0000219. Pecan Street is a 501(c)(3) smart grid/clean energy research and development organization headquartered at The University of Texas at Austin (UT). Pecan Street worked in collaboration with Austin Energy, UT, Environmental Defense Fund (EDF), the City of Austin, the Austin Chamber of Commerce and selected consultants, contractors, and vendors to take a more detailed look at the energy load of residential and small commercial properties while the power industry is undergoing modernization. The Pecan Street Smart Grid Demonstration Program signed-up over 1,000 participants who are sharing their home or businesses’s electricity consumption data with the project via green button protocols, smart meters, and/or a home energy monitoring system (HEMS). Pecan Street completed the installation of HEMS in 750 homes and 25 commercial properties. The program provided incentives to increase the installed base of roof-top solar photovoltaic (PV) systems, plug-in electric vehicles with Level 2 charging, and smart appliances. Over 200 participants within a one square mile area took advantage of Austin Energy and Pecan Street’s joint PV incentive program and installed roof-top PV as part of this project. Of these homes, 69 purchased or leased an electric vehicle through Pecan Street’s PV rebate program and received a Level 2 charger from Pecan Street. Pecan Street studied the impacts of these technologies along with a variety of consumer behavior interventions, including pricing models, real-time feedback on energy use, incentive programs, and messaging, as well as the corresponding impacts on Austin Energy’s distribution assets.The primary demonstration site was the Mueller community in Austin, Texas. The Mueller development, located less than three miles from the Texas State Capitol

  20. Incidence-severity relationships for scab on foliage and fruit of pecan

    Science.gov (United States)

    Venturia effusa is the causal agent of pecan scab, the most prevalent disease of pecan in the southeastern US. Venturia effusa is currently only known to reproduce asexually, yet the genetic diversity among populations of pecan scab suggest it is a sexually reproducing pathogen. Analysis of the mati...

  1. In vitro evidence for sexual reproduction in Venturia effusa, causal agent of pecan scab

    Science.gov (United States)

    Venturia effusa is the causal agent of pecan scab, the most prevalent disease of pecan in the southeastern US. Venturia effusa is currently only known to reproduce asexually, yet the genetic diversity among populations of pecan scab suggest it is a sexually reproducing pathogen. Analysis of the mati...

  2. 76 FR 71276 - Common Crop Insurance Regulations; Pecan Revenue Crop Insurance Provisions

    Science.gov (United States)

    2011-11-17

    ...-0008] RIN 0563-AC35 Common Crop Insurance Regulations; Pecan Revenue Crop Insurance Provisions AGENCY... Corporation (FCIC) proposes to amend the Common Crop Insurance Regulations, Pecan Revenue Crop Insurance... Regulations (7 CFR part 457) by revising Sec. 457.167 Pecan Revenue Crop Insurance Provisions, to be effective...

  3. Scab susceptibility of a provenance collection of pecan in in the southeastern USA

    Science.gov (United States)

    Pecan scab is the most economically destructive disease of pecan in the Southeast US. It is spread in rain and is widespread in the Southeast where conditions conducive to epidemics. A provenance collection of pecan from 19 locations representing the native range of the tree is located in Byron, Geo...

  4. The role of phosphites in scab management and residues in pecan kernels

    Science.gov (United States)

    Phosphite fungicides are used to manage pecan scab (caused by Fusicladium effusum), the most economically destructive disease of pecan in the Southeast US. The EU has imposed a minimum residue limit (MRL) on these fungicides in pecan kernels. Data shows that the phosphite residue exceeds the 2 ppm M...

  5. Insecticide assays against the brown stink bug feeding on pecan

    Science.gov (United States)

    The brown stink bug, Euschistus servus (Say) (Hemiptera: Pentatomidae), is an economic pest of pecan, Carya illinoinensis (Wangenh) K. Koch (Juglandaceae), and other agronomic crops across the southeastern U.S. Management of this pest is mainly via insecticides. Many commercial products indicate o...

  6. Influence of fungicides on gas exchange of pecan foliage

    Science.gov (United States)

    There are several fungicide chemistries used for disease control on pecan (Carya illinoinensis), but there is little or no knowledge of subtle short- or long-term side-effects of these chemistries on host physiological processes, including photosynthesis (Pn). This study quantifies the impact of se...

  7. Sucrose metabolic pathways in sweetgum and pecan seedlings

    Science.gov (United States)

    S.S. Sung; P.P. Kormanik; D.P. Xu; C.C. Black

    1989-01-01

    Sucrose metabolism and glycolysis were studied in one- to two-year-old seedlings of sweetgum (Liquidambar styraciflua L.) and pecan (Carya illinoinensis (Wangenh.) C. Koch). The sucrose synthase pathway was identified as the dominant sucrose metabolic activity in sucrose sink tissues such as terminal buds and the root cambial...

  8. Synthesis of Pisolithus Ectomycorrhizae on Pecan Seedlings in Fumigated Soil

    Science.gov (United States)

    Donald H. Marx

    1979-01-01

    Curtis variety of pecan (Carya illinoensis) seedlings were grown for 8 months in fumigated soil infested at sowing with mycelial inoculum of Pisolithus tinctorius. Pisolithus ectomycorrhizae were formed on all inoculated seedlings and significantly improved their growth over control seedlings. Inoculated and control seedlings also formed ectomycorrhizae with naturally...

  9. Meloidogyne partityla on Pecan Isozyme Phenotypes and Other Host

    Science.gov (United States)

    Starr, J. L.; Tomaszewski, E. K.; Mundo-Ocampo, M.; Baldwin, J. G.

    1996-01-01

    Meloidogyne sp. from five pecan (Carya illinoensis) orchards in Texas were distinctive in host range and iszoyme profiles from common species of Meloidogyne but were morphologically congruent with Meloidogyne partityla Kleynhans, a species previously known only in South Africa. In addition to pecan, species of walnut (Juglans hindsii and J. regia) and hickory (C. ovata) also were hosts. No reproduction was observed on 15 other plant species from nine families, including several common hosts of other Meloidogyne spp. Three esterase phenotypes and two malate dehydrogenase phenotypes of M. partityla were identified by polyacrylamide gel electrophoresis. Each of these isozyme phenotypes was distinct from those of the more common species M. arenaria, M. hapla, M. incognita, and M. javanica. PMID:19277175

  10. Meloidogyne partityla on Pecan Isozyme Phenotypes and Other Host.

    Science.gov (United States)

    Starr, J L; Tomaszewski, E K; Mundo-Ocampo, M; Baldwin, J G

    1996-12-01

    Meloidogyne sp. from five pecan (Carya illinoensis) orchards in Texas were distinctive in host range and iszoyme profiles from common species of Meloidogyne but were morphologically congruent with Meloidogyne partityla Kleynhans, a species previously known only in South Africa. In addition to pecan, species of walnut (Juglans hindsii and J. regia) and hickory (C. ovata) also were hosts. No reproduction was observed on 15 other plant species from nine families, including several common hosts of other Meloidogyne spp. Three esterase phenotypes and two malate dehydrogenase phenotypes of M. partityla were identified by polyacrylamide gel electrophoresis. Each of these isozyme phenotypes was distinct from those of the more common species M. arenaria, M. hapla, M. incognita, and M. javanica.

  11. Shell Venster

    International Nuclear Information System (INIS)

    De Wit, P.; Looijesteijn, B.; Regeer, B.; Stip, B.

    1995-03-01

    In the bi-monthly issues of 'Shell Venster' (window on Shell) attention is paid to the activities of the multinational petroleum company Shell Nederland and the Koninklijke/Shell Groep by means of non-specialist articles

  12. Severity of scab and its effects on fruit weight in mechanically hedge-pruned and topped pecan trees

    Science.gov (United States)

    Scab is the most damaging disease of pecan in the southeastern USA. Pecan trees can attain 44 m in height, so managing disease in the upper canopy is a problem. Fungicide is ordinarily applied using ground-based air-blast sprayers. Although mechanical hedge-pruning and topping of pecan is done for s...

  13. Control of key pecan insect pests using biorational pesticides.

    Science.gov (United States)

    Shapiro-Ilan, David I; Cottrell, Ted E; Jackson, Mark A; Wood, Bruce W

    2013-02-01

    Key pecan insect pests include the black pecan aphid, Melanocallis caryaefoliae (Davis), pecan weevil, Curculio caryae (Horn), and stink bugs (Hemiptera: Pentatomidae). Alternative control tactics are needed for management of these pests in organic and conventional systems. Our objective was to evaluate the potential utility of several alternative insecticides including three plant extract formulations, eucalyptus extract, citrus extract-8.92%, and citrus extract-19.4%, and two microbial insecticides, Chromobacterium subtsugae (Martin et al.) and Isaria fumosorosea (Wize). In the laboratory, eucalyptus extract, citrus extract-8.92%, citrus extract-19.4%, and C. subtsugae caused M. caryaefoliae mortality (mortality was reached approximately 78, 83, and 96%, respectively). In field tests, combined applications of I. fumosorosea with eucalyptus extract were synergistic and caused up to 82% mortality in M. caryaefoliae. In laboratory assays focusing on C. caryae suppression, C. subtsugae reduced feeding and oviposition damage, eucalyptus extract and citrus extract-19.4% were ineffective, and antagonism was observed when citrus extract-19.4% was combined with the entomopathogenic nematode, Steinernema carpocapsae (Weiser). In field tests, C. subtsugae reduced C. caryae damage by 55% within the first 3d, and caused 74.5% corrected mortality within 7 d posttreatment. In the laboratory, C. subtsugae and eucalyptus extract did not cause mortality in the brown stink bug, Euschistus servus (Say). Applications of C. subtsugae for suppression of C. caryae, and eucalyptus extract plus I. fumosorosea for control of M. caryaefoliae show promise as alternative insecticides and should be evaluated further.

  14. Mobile Disdrometer Observations of Nocturnal Mesoscale Convective Systems During PECAN

    Science.gov (United States)

    Bodine, D. J.; Rasmussen, K. L.

    2015-12-01

    Understanding microphysical processes in nocturnal mesoscale convective systems (MCSs) is an important objective of the Plains Elevated Convection At Night (PECAN) experiment, which occurred from 1 June - 15 July 2015 in the central Great Plains region of the United States. Observations of MCSs were collected using a large array of mobile and fixed instrumentation, including ground-based radars, soundings, PECAN Integrated Sounding Arrays (PISAs), and aircraft. In addition to these observations, three mobile Parsivel disdrometers were deployed to obtain drop-size distribution (DSD) measurements to further explore microphysical processes in convective and stratiform regions of nocturnal MCSs. Disdrometers were deployed within close range of a multiple frequency network of mobile and fixed dual-polarization radars (5 - 30 km range), and near mobile sounding units and PISAs. Using mobile disdrometer and multiple-wavelength, dual-polarization radar data, microphysical properties of convective and stratiform regions of MCSs are investigated. The analysis will also examine coordinated Range-Height Indicator (RHI) scans over the disdrometers to elucidate vertical DSD structure. Analysis of dense observations obtained during PECAN in combination with mobile disdrometer DSD measurements contributes to a greater understanding of the structural characteristics and evolution of nocturnal MCSs.

  15. A degree-day model initiated by pheromone trap captures for managing pecan nut casebearer (Lepidoptera: Pyralidae) in pecans.

    Science.gov (United States)

    Knutson, Allen E; Muegge, Mark A

    2010-06-01

    Field observations from pecan, Carya illinoinensis (Wangenh.) Koch, orchards in Texas were used to develop and validate a degree-day model of cumulative proportional adult flight and oviposition and date of first observed nut entry by larvae of the first summer generation of the pecan nut casebearer, Acrobasis nuxvorella Nuenzig (Lepidoptera: Pyralidae). The model was initiated on the date of first sustained capture of adults in pheromone traps. Mean daily maximum and minimum temperatures were used to determine the sum of degree-days from onset to 99% moth flight and oviposition and the date on which first summer generation larvae were first observed penetrating pecan nuts. Cumulative proportional oviposition (y) was described by a modified Gompertz equation, y = 106.05 x exp(-(exp(3.11 - 0.00669 x (x - 1), with x = cumulative degree-days at a base temperature of 3.33 degrees C. Cumulative proportional moth flight (y) was modeled as y = 102.62 x exp(- (exp(1.49 - 0.00571 x (x - 1). Model prediction error for dates of 10, 25, 50, 75, and 90% cumulative oviposition was 1.3 d and 83% of the predicted dates were within +/- 2 d of the observed event. Prediction error for date of first observed nut entry was 2.2 d and 77% of model predictions were within +/- 2 d of the observed event. The model provides ample lead time for producers to implement orchard scouting to assess pecan nut casebearer infestations and to apply an insecticide if needed to prevent economic loss.

  16. Effects of 1,1-Dimethylpiperidinium Chloride on the Pests and Allelochemicals of Cotton and Pecan.

    Science.gov (United States)

    P. A. Hedin; J. N. Jenkins; J. C. McCarty; J. E. Mulrooney; W. L. Parrott; A. Borazjani; C. H. Graves; T. H. Filer

    1984-01-01

    The growth regulator, PIX (mepiquat chloride - 1,1-dimethyl-piperdinium chloride), when applied to cotton (Gossypium hirsutum L.) and pecan (Carya illinoensis Koch), caused internode shortening. PIX did not elicit an increase in resistance in cotton to the tobacco budworm (Heliothis virescens (Fab.)], or in pecan...

  17. The distribution of scab in pecan trees in relation to fruit weight

    Science.gov (United States)

    Pecan scab, caused by Fusicladium effusum is the most destructive disease of pecan in Georgia and elsewhere in the southeastern US. We describe the distribution of scab and measures of yield in relation to sample height in tall trees. Control trees had significantly more severe disease on fruit lowe...

  18. Scab severity in relation to hedge pruning pecan trees in the Southeastern USA

    Science.gov (United States)

    Scab is the most damaging disease of pecan in the Southeastern USA. Pecan trees are tall (up to 30+ m), and managing disease in the upper canopy is problematic. Hedge pruning trees to ~12 m is being explored to facilitate efficacy of ground-based fungicide sprays, but resulting vigorous shoot growth...

  19. [Bromatological characteristics of pecan nuts (Carya illinoensis Koch) cultivated in Brazil].

    Science.gov (United States)

    de Carvalho, V D

    1975-01-01

    The A. studied pecan nuts cultivated in Brazil: two samples represented North American varieties and three others Brazilian hybrids. The comparison between physical classification and chemical composition, specially amino acid contents pointed to non significant differences, all beeing useful for commercial purposes. The A. stresses the importance of the culture of pecan nuts in Brazil.

  20. Estimating water use of mature pecan orchards: A six stage crop growth curve approach

    CSIR Research Space (South Africa)

    Ibraimo, NA

    2016-11-01

    Full Text Available previous study in New Mexico, revealed that a six stage crop coefficient curve should be considered for pecans, together with higher mid-season crop coefficient (K(subc)) values for mature orchards. More accurate estimates of monthly ET for mature pecan...

  1. Discovery and small RNA profile of Pecan mosaic-associated virus, a novel potyvirus of pecan trees.

    Science.gov (United States)

    Su, Xiu; Fu, Shuai; Qian, Yajuan; Zhang, Liqin; Xu, Yi; Zhou, Xueping

    2016-05-26

    A novel potyvirus was discovered in pecan (Carya illinoensis) showing leaf mosaic symptom through the use of deep sequencing of small RNAs. The complete genome of this virus was determined to comprise of 9,310 nucleotides (nt), and shared 24.0% to 58.9% nucleotide similarities with that of other Potyviridae viruses. The genome was deduced to encode a single open reading frame (polyprotein) on the plus strand. Phylogenetic analysis based on the whole genome sequence and coat protein amino acid sequence showed that this virus is most closely related to Lettuce mosaic virus. Using electron microscopy, the typical Potyvirus filamentous particles were identified in infected pecan leaves with mosaic symptoms. Our results clearly show that this virus is a new member of the genus Potyvirus in the family Potyviridae. The virus is tentatively named Pecan mosaic-associated virus (PMaV). Additionally, profiling of the PMaV-derived small RNA (PMaV-sRNA) showed that the most abundant PMaV-sRNAs were 21-nt in length. There are several hotspots for small RNA production along the PMaV genome; two 21-nt PMaV-sRNAs starting at 811 nt and 610 nt of the minus-strand genome were highly repeated.

  2. Early Holocene pecan, Carya illinoensis, in the Mississippi River Valley near Muscatine, Iowa

    Science.gov (United States)

    Bettis, E. Arthur; Baker, R.G.; Nations, B.K.; Benn, D.W.

    1990-01-01

    A fossil pecan, Carya illinoensis (Wang.) K. Koch, from floodplain sediments of the Mississippi River near Muscatine, Iowa, was accelerator-dated at 7280 ?? 120 yr B.P. This discovery indicates that pecan was at or near its present northern limit by that time. Carya pollen profiles from the Mississippi River Trench indicate that hickory pollen percentages were much higher in the valley than at upland locations during the early Holocene. Pecan, the hickory with the most restricted riparian habitat, is the likely candidate for producing these peaks in Carya pollen percentages. Therefore, pecan may have reached its northern limit as early as 10,300 yr B.P. Its abundance in Early Archaic archaeological sites and the co-occurrence of early Holocene Carya pollen peaks with the arrival of the Dalton artifact complex in the Upper Mississippi Valley suggest that humans may have played a role in the early dispersal of pecan. ?? 1990.

  3. Early Holocene pecan, Carya illinoensis, in the Mississippi River Valley near Muscatine, Iowa*1

    Science.gov (United States)

    Bettis, E. Arthur; Baker, Richard G.; Nations, Brenda K.; Benn, David W.

    1990-01-01

    A fossil pecan, Carya illinoensis (Wang.) K. Koch, from floodplain sediments of the Mississippi River near Muscatine, Iowa, was accelerator-dated at 7280 ± 120 yr B.P. This discovery indicates that pecan was at or near its present northern limit by that time. Carya pollen profiles from the Mississippi River Trench indicate that hickory pollen percentages were much higher in the valley than at upland locations during the early Holocene. Pecan, the hickory with the most restricted riparian habitat, is the likely candidate for producing these peaks in Carya pollen percentages. Therefore, pecan may have reached its northern limit as early as 10,300 yr B.P. Its abundance in Early Archaic archaeological sites and the co-occurrence of early Holocene Carya pollen peaks with the arrival of the Dalton artifact complex in the Upper Mississippi Valley suggest that humans may have played a role in the early dispersal of pecan.

  4. Semiochemicals released by pecan alleviate physiological suppression in overwintering larvae of Acrobasis nuxvorella (Lepidoptera: Pyralidae).

    Science.gov (United States)

    Vargas-Arispuro, I; Corella-Madueño, M A G; Harris, M K; Martínez-Téllez, M A; Gardea, A A; Fu-Castillo, A; Orozco-Avitia, A

    2013-10-01

    Acrobasis nuxvorella Neunzig (pecan nut casebearer) is a monophagous herbivore of Carya illinoinensis (Wang.) K. Koch (pecan); both are indigenous to North America, where Carya has evolved for ≈60 million years. We hypothesized that this close association may have resulted in a parallel evolution allowing casebearer to use pecan volatiles to synchronize seasonality. Casebearer overwinters in diapause as a first-instar larva in a hibernaculum attached to a dormant pecan bud. Larval emergence from this structure after diapause or postdiapause quiescence coincides with the onset of pecan bud growth in the spring, and this interaction was the subject of this study. Dormant pecan twigs with hibernacula-infested buds were exposed to a water control or pecan volatiles from 'Western Schley' cultivar, and monitored to observe larval response by using a microcalorimeter. Initial testing showed that metabolic heat produced by overwintering larvae remained low and unchanged when exposed to water vapor and significantly increased within a few hours after exposure to volatiles from new pecan foliage. This shows that these larvae in hibernacula are in a physiologically suppressed state of diapause or postdiapause quiescence, from which they detect and respond to these pecan volatiles. Further studies to quantify larval responses showed that 90 and 80% of the larvae became active and emerged from their hibernacula ≈6 d after exposure to Western Schley and 'Wichita' volatiles, respectively. Mixtures of 13 sesquiterpenes from those pecan volatiles were identified to induce physiological activity within larvae after hours of exposure, followed some days later by larval emergence from hibernacula. Host volatiles, to our knowledge, have not previously been reported to induce early instar larvae in hibernacula to rouse from a state of physiological arrest to resume normal growth and development. This also has potential for use in pest management.

  5. Mycorrhization of pecan (Carya illinoinensis) with black truffles: Tuber melanosporum and Tuber brumale.

    Science.gov (United States)

    Marozzi, Giorgio; Sánchez, Sergio; Benucci, Gian Maria Niccolò; Bonito, Gregory; Falini, Leonardo Baciarelli; Albertini, Emidio; Donnini, Domizia

    2017-04-01

    Pecan, Carya illinoinensis, is an economically important nut producing tree that can establish ectomycorrhizal symbiosis with a high diversity of fungi. In the southern USA, truffles (Tuber spp.) sometimes fruit prolifically in cultivated pecan orchards and regularly associate with pecan roots as ectomycorrhizae (ECMs). It has been demonstrated that some valuable European truffle species (e.g., Tuber borchii and Tuber aestivum) can form ECMs with pecan seedlings in nursery conditions. Thus, pecan may represent an attractive alternative host to forest trees for truffle growers given the potential for co-cropping truffles and pecans. To further explore the capacity of pecan to host truffle symbionts, pecan seedlings were inoculated with species of black truffles that are economically important in Europe, T. melanosporum and T. brumale. Ectomycorrhizae were characterized molecularly and their morphology was described in detail. Mycorrhization rates on pecan roots were assessed over a 2-year period. Tuber melanosporum and T. brumale produced well-formed ECMs with a level of root colonization in the first year of 37.3 and 34.5%, respectively. After 24 months, the level of mycorrhization increased for T. brumale (49.4%) and decreased for T. melanosporum (10.5%) inversely to that of non-target ECM greenhouse contaminants (e.g., Sphaerosporella brunnea, Trichophaea woolhopeia, Pulvinula constellatio). To assess whether mating types segregated in T. melanosporum as been reported for other host species, we amplified the mating-type locus from single T. melanosporum ECM belonging to different seedlings over a 2-year period. The two mating idiomorphs were nearly equally represented along the 2-year time span: MAT 1-1-1 decreased from 59.4% in the first year to 48.5% in the second year after inoculation. Data reported in this study add to knowledge on the mycorrhization of pecan trees with commercial truffles and has application to truffle and nut co-cropping systems.

  6. A Comparison of Flavor Differences between Pecan Cultivars in Raw and Roasted Forms.

    Science.gov (United States)

    Magnuson, Shelby M; Kelly, Brendan; Koppel, Kadri; Reid, William

    2016-05-01

    The objective of this research was to explore sensory differences among 8 different pecan cultivars ("Pawnee," "Witte," "Kanza," "Major," "Lakota," "Giles," "Maramec," "Chetopa") in raw and roasted forms. The cultivars were collected from 2 growing seasons (2013 and 2014) and evaluated separately. Trained panelists evaluated each cultivar from each season in raw and roasted forms, measuring intensities of 20 flavor attributes using descriptive analysis. The intensities of 10 of the 20 flavor attributes were higher for the roasted pecans across all cultivars. These included pecan ID, overall nutty, nutty-woody, nutty-grainlike, nutty-buttery, brown, caramelized, roasted, overall sweet, and sweet. The cultivars exhibited significant differences from one another for 8 attributes: pecan ID, nutty-buttery, caramelized, acrid, woody, oily, astringent, and bitter. Each of the cultivars displayed unique flavor profiles with some demonstrating extremes of certain attributes, for example the high astringency of "Lakota" or the buttery characteristics of "Pawnee." These results may help pecan growers and pecan product manufacturers understand flavor differences between different varieties of pecans, both in raw and roasted states, and the changes that occur during this process. © 2016 Institute of Food Technologists®

  7. Lidar Profiling In the lower Troposphere: experience from PECAN

    Science.gov (United States)

    Demoz, Belay B.; Delgado, Ruben; Caroll, Brian; Vermeesch, Kevin; Whiteman, David N.; Sakai, Ricardo; Tesfay, Sium; Cooper, Lorenza

    2018-04-01

    Results from the PECAN (Plains Elevated Convection at Night) campaign are discussed. In particular, the utility of simple backscatter lidars/ceilometers in quantifying atmospheric dynamics parameters and variables as well as evolution of the lower tropospheric dynamics are made. Cases of bore wave dynamics and the potential of these events in lofting of low level, moist, airmass and its consequence in thunderstorm initiation are made. A suite of thermodynamic profiling instruments are combined and compared to describe and visualize lower tropospheric dynamic evolution.

  8. Germination and development of pecan cultivar seedlings by seed stratification

    Directory of Open Access Journals (Sweden)

    Igor Poletto

    2015-12-01

    Full Text Available Abstract: The objective of this work was to evaluate the effect of seed stratification on germination rate, germination speed, and initial development of seedlings of six pecan (Carya illinoinensis cultivars under subtropical climatic conditions in southern Brazil. For stratification, the seeds were placed in boxes with moist sand, in a cold chamber at 4°C, for 90 days. In the fourteenth week after sowing, the emergence speed index, total emergence, plant height, stem diameter, and number of leaves were evaluated. Seed stratification significantly improves the germination potential and morphological traits of the evaluated cultivars.

  9. Gap probability - Measurements and models of a pecan orchard

    Science.gov (United States)

    Strahler, Alan H.; Li, Xiaowen; Moody, Aaron; Liu, YI

    1992-01-01

    Measurements and models are compared for gap probability in a pecan orchard. Measurements are based on panoramic photographs of 50* by 135 view angle made under the canopy looking upwards at regular positions along transects between orchard trees. The gap probability model is driven by geometric parameters at two levels-crown and leaf. Crown level parameters include the shape of the crown envelope and spacing of crowns; leaf level parameters include leaf size and shape, leaf area index, and leaf angle, all as functions of canopy position.

  10. Lidar Profiling In the lower Troposphere: experience from PECAN

    Directory of Open Access Journals (Sweden)

    Demoz Belay B.

    2018-01-01

    Full Text Available Results from the PECAN (Plains Elevated Convection at Night campaign are discussed. In particular, the utility of simple backscatter lidars/ceilometers in quantifying atmospheric dynamics parameters and variables as well as evolution of the lower tropospheric dynamics are made. Cases of bore wave dynamics and the potential of these events in lofting of low level, moist, airmass and its consequence in thunderstorm initiation are made. A suite of thermodynamic profiling instruments are combined and compared to describe and visualize lower tropospheric dynamic evolution.

  11. Dormancy overcome and seedling quality of pecan in nursery

    Directory of Open Access Journals (Sweden)

    Tales Poletto

    Full Text Available ABSTRACT: This study evaluated the efficiency of methods to overcome seed dormancy in different storage periods in the production of pecan seedlings. Seeds were submitted to the following treatments: T1, T4 and T7 - control treatments (seeds with no treatment, stored at room temperature for 30, 60 and 90 days, respectively, T2, T5 and T8 - stratification (seeds were distributed in boxes with wet sand maintained at a temperature of 4°C for 30, 60 and 90 days, respectively, T3, T6 and T9 - scarification + stratification (seeds scarified with sandpaper n.80 and stratified by 30, 60 and 90 days, respectively, in completely random experimental design. Plant height, stem diameter, number of leaves, full emergence and emergence speed index (ESI were evaluated after 14 weeks of sowing. The best development of pecan 'plants, their emergence, and ESI were observed in the stratification treatment for 90 day as well as in the scarification + stratification treatment for 90 day. Storing seeds in uncontrolled environment reduced their viability.

  12. Transformation of pecan and regeneration of transgenic plants.

    Science.gov (United States)

    McGranahan, G H; Leslie, C A; Dandekar, A M; Uratsu, S L; Yates, I E

    1993-09-01

    A gene transfer system developed for walnut (Juglans regia L.) was successfully applied to pecan (Carya illinoensis [Wang] K. Koch). Repetitively embryogenic somatic embryos derived from open-pollinated seed of 'Elliott', 'Wichita', and 'Schley' were co-cultivated with Agrobacterium strain EHA 101/pCGN 7001, which contains marker genes for beta-glucuronidase activity and resistance to kanamycin. Several modifications of the standard walnut transformation techniques were tested, including a lower concentration of kanamycin and a modified induction medium, but these treatments had no measurable effect on efficiency of transformation. Nineteen of the 764 viable inoculated embryos produced transgenic subclones; 13 of these were from the line 'Elliott'6, 3 from 'Schley'5/3, and 3 from 'Wichita'9. Transgenic embryos of 'Wichita'9 germinated most readily and three subclones were successfully micropropagated. Three transgenic plants of one of these subclones were obtained by grafting the tissue cultured shoots to seedling pecan rootstock in the greenhouse. Gene insertion, initially detected by GUS activity, was confirmed by detection of integrated T-DNA sequences using Southern analysis.

  13. Toxicity to Chicks of Aspergillus and Penicillium Species Isolated from Moldy Pecans 1

    Science.gov (United States)

    Doupnik, Ben; Bell, D. K.

    1971-01-01

    Isolates of Aspergillus chevalieri, A. flavus, A. ochraceus, A. repens, and Penicillium funiculosum and complexes of P. citrinum-P. implicatum isolated from moldy pecan meats were toxic to chicks. PMID:5564681

  14. Suppressive effects of metabolites from Photorhabdus spp. and Xenorhabdus spp. on phytopathogens of peach and pecan

    Science.gov (United States)

    Our objective was to determine the suppressive abilities of bacterial metabolites derived from Photorhabdus and Xenorhabdus spp. on Glomerella cingulata, Phomopsis sp., Phytophthora cactorum, and Fusicladosporium effusum, which are fungal or oomycete pathogens of pecan, and Monilinia fructicola, a f...

  15. Are simple empirical crop coefficient approaches for determining pecan water use readily transferrable across a wide range of conditions?

    CSIR Research Space (South Africa)

    Taylor, NJ

    2017-02-01

    Full Text Available , such as the United States of America, Mexico, South Africa and Australia (INC, 2011), the majority of pecan research has been conducted in the USA. Studies conducted in New Mexico suggest that seasonal crop evapotranspiration (ET) of flood irrigated... coefficient modelling approach to estimate water use of pecans Evapotranspiration was estimated using a pecan specific model from New Mexico (Samani et al., 2011) which relates crop coefficients and orchard water use to canopy cover as follows...

  16. Expression, purification and crystallization of pecan (Carya illinoinensis) vicilin.

    Science.gov (United States)

    Lee, BoRam; Zhang, Renhao; Du, Wen-Xian; Grauke, Larry J; McHugh, Tara H; Zhang, Yu-Zhu

    2014-08-01

    Tree nuts are responsible for many cases of severe food allergies. The 7S seed storage protein vicilin has been identified as a food allergen in many kinds of tree nuts. The vicilin protein consists of an N-terminal low-complexity region with antimicrobial activity and a C-terminal domain that forms a trimeric structure that belongs to the cupin superfamily. In this study, vicilin from pecan (Carya illinoinensis) was isolated and was expressed in bacteria for the first time. The cupin structural core of the protein, residues 369-792, was purified by metal-affinity and gel-filtration chromatography to high purity. Vicilin crystals were obtained and the best crystal diffracted to 2.65 Å resolution in space group P212121.

  17. 7 CFR 983.29 - Shelled pistachios.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Shelled pistachios. 983.29 Section 983.29 Agriculture... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE PISTACHIOS GROWN IN CALIFORNIA, ARIZONA, AND NEW MEXICO Definitions § 983.29 Shelled pistachios. Shelled pistachios means pistachio...

  18. 7 CFR 981.6 - Shelled almonds.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Shelled almonds. 981.6 Section 981.6 Agriculture... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ALMONDS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 981.6 Shelled almonds. Shelled almonds mean raw or roasted almonds after...

  19. Genetic Diversity and Identification of Chinese-Grown Pecan Using ISSR and SSR Markers

    Directory of Open Access Journals (Sweden)

    Zhong-Ren Guo

    2011-12-01

    Full Text Available Pecan is an important horticultural nut crop originally from North America and now widely cultivated in China for its high ecological, ornamental and economic value. Currently, there are over one hundred cultivars grown in China, including introduced American cultivars and Chinese seedling breeding cultivars. Molecular markers were used to assess the genetic diversity of these cultivars and to identify the pedigrees of fine pecan plants with good characteristics and no cultivar-related data. A total of 77 samples grown in China were studied, including 14 introduced cultivars, 12 domestic seedling breeding cultivars, and 49 fine pecan plants with no cultivar data, together with Carya cathayensis and Juglans nigra. A total of 77 ISSR and 19 SSR primers were prescreened; 10 ISSR and eight SSR primers were selected, yielding a total of 94 amplified bands (100% polymorphic in the range of 140–1,950 bp for the ISSR and 70 amplified bands (100% polymorphic in the range of 50–350 bp for SSR markers. Genetic diversity analyses indicated Chinese-grown pecan cultivars and fine plants had significant diversity at the DNA level. The dengrograms constructed with ISSR, SSR or combined data were very similar, but showed very weak grouping association with morphological characters. However, the progeny were always grouped with the parents. The great diversity found among the Chinese cultivars and the interesting germplasm of the fine pecan plants analyzed in this study are very useful for increasing the diversity of the pecan gene pool. All 77 accessions in this study could be separated based on the ISSR and SSR fingerprints produced by one or more primers. The results of our study also showed that ISSR and SSR techniques were both suitable for genetic diversity analyses and the identification of pecan resources.

  20. Genetic diversity and identification of Chinese-grown pecan using ISSR and SSR markers.

    Science.gov (United States)

    Jia, Xiao-Dong; Wang, Tao; Zhai, Min; Li, Yong-Rong; Guo, Zhong-Ren

    2011-12-06

    Pecan is an important horticultural nut crop originally from North America and now widely cultivated in China for its high ecological, ornamental and economic value. Currently, there are over one hundred cultivars grown in China, including introduced American cultivars and Chinese seedling breeding cultivars. Molecular markers were used to assess the genetic diversity of these cultivars and to identify the pedigrees of fine pecan plants with good characteristics and no cultivar-related data. A total of 77 samples grown in China were studied, including 14 introduced cultivars, 12 domestic seedling breeding cultivars, and 49 fine pecan plants with no cultivar data, together with Carya cathayensis and Juglans nigra. A total of 77 ISSR and 19 SSR primers were prescreened; 10 ISSR and eight SSR primers were selected, yielding a total of 94 amplified bands (100% polymorphic) in the range of 140-1,950 bp for the ISSR and 70 amplified bands (100% polymorphic) in the range of 50-350 bp for SSR markers. Genetic diversity analyses indicated Chinese-grown pecan cultivars and fine plants had significant diversity at the DNA level. The dengrograms constructed with ISSR, SSR or combined data were very similar, but showed very weak grouping association with morphological characters. However, the progeny were always grouped with the parents. The great diversity found among the Chinese cultivars and the interesting germplasm of the fine pecan plants analyzed in this study are very useful for increasing the diversity of the pecan gene pool. All 77 accessions in this study could be separated based on the ISSR and SSR fingerprints produced by one or more primers. The results of our study also showed that ISSR and SSR techniques were both suitable for genetic diversity analyses and the identification of pecan resources.

  1. Transcriptome Analysis of Genes Involved in Lipid Biosynthesis in the Developing Embryo of Pecan (Carya illinoinensis).

    Science.gov (United States)

    Huang, Ruimin; Huang, Youjun; Sun, Zhichao; Huang, Jianqin; Wang, Zhengjia

    2017-05-24

    Pecan (Carya illinoinensis) is an important woody tree species because of the high content of healthy oil in its nut. Thus far, the pathways and key genes related to oil biosynthesis in developing pecan seeds remain largely unclear. Our analyses revealed that mature pecan embryo accumulated more than 80% oil, in which 90% was unsaturated fatty acids with abundant oleic acid. RNA sequencing generated 84,643 unigenes in three cDNA libraries prepared from pecan embryos collected at 105, 120, and 165 days after flowering (DAF). We identified 153 unigenes associated with lipid biosynthesis, including 107 unigenes for fatty acid biosynthesis, 34 for triacylglycerol biosynthesis, 7 for oil bodies, and 5 for transcription factors involved in oil synthesis. The genes associated with fatty acid synthesis were the most abundantly expressed genes at 120 DAF. Additionally, the biosynthesis of oil began to increase while crude fat contents increased from 16.61 to 74.45% (165 DAF). We identified four SAD, two FAD2, one FAD6, two FAD7, and two FAD8 unigenes responsible for unsaturated fatty acid biosynthesis. However, FAD3 homologues were not detected. Consequently, we inferred that the linolenic acid in developing pecan embryos is generated by FAD7 and FAD8 in plastids rather than FAD3 in endoplasmic reticula. During pecan embryo development, different unigenes are expressed for plastidial and cytosolic glycolysis. Plastidial glycolysis is more relevant to lipid synthesis than cytosolic glycolysis. The 18 most important genes associated with lipid biosynthesis were evaluated in five stages of developing embryos using quantitative PCR (qPCR). The qPCR data were well consistent with their expression in transcriptomic analyses. Our data would be important for the metabolic engineering of pecans to increase oil contents and modify fatty acid composition.

  2. Mycorrhization of pecan trees (Carya illinoinensis) with commercial truffle species: Tuber aestivum Vittad. and Tuber borchii Vittad.

    Science.gov (United States)

    Benucci, Gian Maria Niccolò; Bonito, Gregory; Baciarelli Falini, Leonardo; Bencivenga, Mattia

    2012-07-01

    Pecan (Carya illinoinensis) is an economically important nut tree native to the Mississippi basin and cultivated worldwide. In North America, species of truffles are regularly found fruiting in productive pecan orchards and the truffle genus Tuber appears to be abundant in pecan ectomycorrhizal (EM) communities. As an initial step to determine the feasibility of co-cropping European truffle species with pecan, we evaluated whether mycorrhizae of highly esteemed European truffle species (Tuber aestivum Vittad. T. borchii and T. macrosporum) could be formed on pecan seedlings. Seedlings were inoculated with truffle spores and were grown in a greenhouse for 10 months. Levels of EM colonization were estimated visually and quantified by counting EM tips. Ectomycorrhizae were identified both morphologically and molecularly with species-specific amplification and by sequencing of the ITS region of the nuclear ribosomal DNA (nrDNA). Both T. borchii and T. aestivum spores produced well-formed ectomycorrhizae on pecan seedlings with average root colonization levels of about 62% and 42%, respectively, whereas no ectomycorrhizae of T. macrosporum were formed. The anatomy and morphology of these truffle ectomycorrhizae on pecan was characterized. The co-cropping of T. aestivum and T. borchii may hold promise as an additional stream of revenue to pecan growers, although, further studies are needed to assess whether this symbiosis is maintained after planting in the field and whether truffle production can be supported by this host species.

  3. Changes in ultraviolet-B and visible optical properties and absorbing pigment concentrations in pecan leaves during a growing season

    Science.gov (United States)

    Yadong Qi; Shuju Bai; Gordon M. Heisler

    2003-01-01

    UV-B (280-320 nm) and visible (400-760 nm) spectral reflectance, transmittance, and absorptance; chlorophyll content; UV-B absorbing compound concentration; and leaf thickness were measured for pecan (Carya illinoensis) leaves over a growing season (April-October). Leaf samples were collected monthly from a pecan plantation located on the Southern...

  4. Establishment and early development of 'Kanza', 'Peruque', and other pecan cultivars in northern U.S. growing regions

    Science.gov (United States)

    Most pecan (Carya illinoensis) nut production in the northern range of the species (Missouri, Kansas, Northern Arkansas) is from managed wild trees. Orchards of trees grafted to improved cultivars are slowly being established in the region as economic opportunities improve. Pecan cultivars that are ...

  5. Effects of entomopathogenic fungus species, and impact of fertilizers, on biological control of pecan weevil (Coleoptera: Curculionidae)

    Science.gov (United States)

    The pecan weevil, Curculio caryae (Horn), is a key pest of pecan. Prior research indicated potential to use Hypocreales fungi for suppression of C. caryae. In this study, we first compared the efficacy of two fungal spp. Beauveria bassiana (GHA strain) and Metarhizium brunneum (F52) in ability to ...

  6. Identification and Characterization of a New Pecan [Carya illinoinensis (Wangenh.) K. Koch] Allergen, Car i 2.

    Science.gov (United States)

    Zhang, Yuzhu; Lee, BoRam; Du, Wen-Xian; Lyu, Shu-Chen; Nadeau, Kari C; Grauke, Larry J; Zhang, Yan; Wang, Shuo; Fan, Yuting; Yi, Jiang; McHugh, Tara H

    2016-05-25

    The 7S vicilin and 11S legumin seed storage globulins belong to the cupin protein superfamily and are major food allergens in many foods from the "big eight" food allergen groups. Here, for the first time, pecan vicilin was found to be a food allergen. Western blot experiments revealed that 30% of 27 sera used in this study and 24% of the sera from 25 patients with double-blind, placebo controlled clinical pecan allergy contained IgE antibodies specific to pecan vicilin. This allergen consists of a low-complexity region at its N-terminal and a structured domain at the C-terminal that contains two cupin motifs and forms homotrimers. The crystal structure of recombinant pecan vicilin was determined. The refined structure gave R/Rfree values of 0.218/0.262 for all data to 2.65 Å. There were two trimeric biological units in the crystallographic asymmetric unit. Pecan vicilin is also a copper protein. These data may facilitate the understanding of the nutritional value and the allergenicity relevance of the copper binding property of seed storage proteins in tree nuts.

  7. Interaction of Concurrent Populations of Meloidogyne partityla and Mesocriconema xenoplax on Pecan

    Science.gov (United States)

    Wood, B. W.

    2008-01-01

    The effect of the interaction between Meloidogyne partityla and Mesocriconema xenoplax on nematode reproduction and vegetative growth of Carya illinoinensis ‘Desirable’ pecan was studied in field microplots. Meloidogyne partityla suppressed reproduction of M. xenoplax, whereas the presence of M. xenoplax did not affect the population density of M. partityla second-stage juveniles in soil. Above-ground tree growth, as measured by trunk diameter 32 months following inoculation, was reduced in the presence of M. partityla alone or in combination with M. xenoplax as compared with the uninoculated control trees. The interaction between M. partityla and M. xenoplax was significant for dry root weight 37 months after inoculation. Results indicate that the presence of the two nematode species together caused a greater reduction in root growth than M. xenoplax alone, but not when compared to M. partityla alone. Mouse-ear symptom severity in pecan leaves was increased in the presence of M. partityla compared with M. xenoplax and the uninoculated control. Infection with M. partityla increased severity of mouse-ear symptoms expressed by foliage. The greater negative impact of M. partityla on vegetative growth of pecan seedlings in field microplots indicates that it is likely a more detrimental pathogen to pecan than is M. xenoplax and is likely an economic pest of pecan. PMID:19440263

  8. Ectomycorrhizal fungal diversity in orchards of cultivated pecan (Carya illinoinensis; Juglandaceae).

    Science.gov (United States)

    Bonito, Gregory; Brenneman, Timothy; Vilgalys, Rytas

    2011-10-01

    Carya illinoinensis (pecan) belongs to the Juglandaceae (walnut family) and is a major economic nut crop in the southern USA. Although evidence suggests that some species in the Juglandaceae are ectomycorrhizal, investigations on their ectomycorrhizal fungal symbionts are quite limited. Here we assessed the ectomycorrhizal fungal diversity in cultivated orchards of C. illinoinensis. Five pecan orchards in southern Georgia, USA, were studied, three of which were known to fruit the native edible truffle species Tuber lyonii. We sequenced rDNA from single ectomycorrhizal root tips sampled from a total of 50 individual trees. Mycorrhizae were identified by ITS and LSU rDNA sequence-based methods. Forty-four distinct ectomycorrhizal taxa were detected. Sequestrate taxa including Tuber and Scleroderma were particularly abundant. The two most abundant sequence types belonged to T. lyonii (17%) and an undescribed Tuber species (~20%). Because of our interest in the ecology of T. lyonii, we also conducted greenhouse studies to determine whether this species would colonize and form ectomycorrhizae on roots of pecan, oak, or pine species endemic to the region. T. lyonii ectomycorrhizae were formed on pecan and oak seedlings, but not pine, when these were inoculated with spores. That oak and pecan seedling roots were receptive to truffle spores indicates that spore slurry inoculation could be a suitable method for commercial use and that, ecologically, T. lyonii may function as a pioneer ectomycorrhizal species for these hosts. © Springer-Verlag 2011

  9. Effects of combining microbial and chemical insecticides on mortality of the Pecan Weevil (Coleoptera: Curculionidae).

    Science.gov (United States)

    Shapiro-Ilan, David I; Cottrell, Ted E; Wood, Bruce W

    2011-02-01

    The pecan weevil, Curculio caryae (Horn), is a key pest of pecan [Carya illinoinensis (Wangenh.) K. Koch]. Current control recommendations are based on chemical insecticide applications. Microbial control agents such as the entomopathogenic nematode, Steinernema carpocapsae (Weiser) and the fungus Beauveria bassiana (Balsamo) Vuillemin occur naturally in southeastern U.S. pecan orchards and have shown promise as alternative control agents for C. caryjae. Conceivably, the chemical and microbial agents occur simultaneously within pecan orchards or might be applied concurrently. The objective of this study was to determine the interactions between two chemical insecticides that are used in commercial C. caryae control (i.e., carbaryl and cypermethrin applied below field rates) and the microbial agents B. bassiana and S. carpocapsae. In laboratory experiments, pecan weevil larval or adult mortality was assessed after application of microbial or chemical treatments applied singly or in combination (microbial + chemical agent). The nature of interactions (antagonism, additivity, or synergy) in terms of weevil mortality was evaluated over 9 d (larvae) or 5 d (adults). Results for B. bassiana indicated synergistic activity with carbaryl and antagonism with cypermethrin in C. caryae larvae and adults. For S. carpocapsae, synergy was detected with both chemicals in C. caryae larvae, but only additive effects were detected in adult weevils. Our results indicate that the chemical-microbial combinations tested are compatible with the exception of B. bassiana and cypermethrin. In addition, combinations that exhibited synergistic interactions may provide enhanced C. caryae control in commercial field applications; thus, their potential merits further exploration.

  10. Chasing the long tail of environmental data: PEcAn is nuts about Brown Dog

    Science.gov (United States)

    Dietze, M.; Cowdery, E.; Desai, A. R.; Gardella, A.; Kelly, R.; Kooper, R.; LeBauer, D.; Mantooth, J.; McHenry, K.; Serbin, S.; Shiklomanov, A. N.; Simkins, J.; Viskari, T.; Raiho, A.

    2015-12-01

    The Predictive Ecosystem Analyzer (PEcAn) is a ecological modeling informatics system that manages the flows of information in and out of terrestrial biosphere models, provenance tracking, visualization, analysis, and model-data fusion. We are in the process of scaling the PEcAn system from one that currently supports a handful of models and system nodes to one that aims to provide bottom-up connectivity across much of the model-data integration done by the terrestrial biogeochemistry community. This talk reports on the current state of PEcAn, it's data processing workflows, and the near- and long-term challenges faced. Particular emphasis will be given to the tools being developed by the Brown Dog project to make unstructured, un-curated data more accessible: the Data Access Proxy (DAP) and the Data Tilling Service (DTS). The use of the DAP to process meteorological data and the DTS to read vegetation data will be demonstrated and other Brown Dog environmental case studies will be briefly touched on. Beyond data processing, facilitating data discovery and import into PEcAn and distributing analyses across the PEcAn network (i.e. bringing models to data) are key challenges moving forward.

  11. Antigenic stability of pecan [Carya illinoinensis (Wangenh.) K. Koch] proteins: effects of thermal treatments and in vitro digestion.

    Science.gov (United States)

    Venkatachalam, Mahesh; Teuber, Suzanne S; Peterson, W Rich; Roux, Kenneth H; Sathe, Shridhar K

    2006-02-22

    Rabbit polyclonal antibody-based inhibition ELISA as well as immunoblotting analyses of proteins extracted from variously processed pecans (cv. Desirable) indicate that pecan proteins are antigenically stable. Pecan antigens were more sensitive to moist heat than dry heat processing treatments. SDS-PAGE and immunoblotting analysis of the native and heat-denatured proteins that were previously subjected to in vitro simulated gastric fluid digestions indicate that stable antigenic peptides were produced. Both enzyme-to-substrate ratio and digestion time were influential in determining the stability of pecan polypeptides. The stable antigenic polypeptides may serve as useful markers in developing assays suitable for the detection of trace amounts of pecans in foods.

  12. Detecting moisture status of pecan orchards and the potential of remotely-sensed surface reflectance data

    Science.gov (United States)

    Othman, Yahia Abdelrahman

    Demand for New Mexico's limited water resources coupled with periodic drought has increased the need to schedule irrigation of pecan orchards based on tree water status. The overall goal of this research was to develop advanced tree water status sensing techniques to optimize irrigation scheduling of pecan orchards. To achieve this goal, I conducted three studies in the La Mancha and Leyendecker orchards, both mature pecan orchards located in the Mesilla Valley, New Mexico. In the first study, I screened leaf-level physiological changes that occurred during cyclic irrigation to determine parameters that best represented changes in plant moisture status. Then, I linked plant physiological changes to remotely-sensed surface reflectance data derived from Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM+). In the second study, I assessed the impact of water deficits that developed during the flood irrigation dry-down cycles on photosynthesis (A) and gas exchange and established preliminary water deficit thresholds of midday stem water potential (Psi smd) critical to A and gas exchange of pecans. In a third study, I investigated whether hyperspectral data obtained from a handheld spectroradiometer and multispectral remotely-sensed data derived from Landsat 7 ETM+ and Landsat 8 Operational Land Imager (OLI) could detect moisture status in pecans during cyclic flood irrigations. I conducted the first study simultaneously in both orchards. Leaf-level physiological responses and remotely-sensed surface reflectance data were collected from trees that were either well watered or in water deficit. Midday stem water potential was the best leaf-level physiological response to detect moisture status in pecans. Multiple linear regression between Psismd and vegetation indices revealed a significant relationship (R 2 = 0.54) in both orchards. Accordingly, I concluded that remotely-sensed multispectral data form Landsat TMETM+ holds promise for detecting the moisture

  13. Movement and degradation of indaziflam in a Pecan Orchrad

    Science.gov (United States)

    Shukla, M. K.; Gonzalez, A.; Ashigh, J.

    2015-12-01

    Indaziflam is a new preemergence herbicide to control annual grass and broadleaf weeds in orchards. Currently there is limited information on its dissipation under field conditions. This study was conducted in a pecan orchard where some trees showed sporadic injury symptoms about four months after applying indaziflam. The objectives of this study were to evaluate the movement of indaziflam due to flood irrigation and determine the rates of degradation of indaziflam. Soil samples were collected at 0-15, 15-30 and 30-46 cm depth 26, 63, 90 and 126 days after treating impacted and unimpacted areas with 0, 36.5 and 73.1 g a.i. ha-1. Indaziflam was detected in soil samples collected at each depth from areas treated with 0, 36.5 and 73.1 g a.i. ha-1 suggesting that indaziflam moved both horizontally and vertically. Average half-life of indaziflam was obtained as 40±11 days and indaziflam concentrations consistently decreased with increasing soil depth and time. Indaziflam concentrations were greater in the unimpacted area than in the impacted area and mass recoveries were greater in plots treated with 36.5 g a.i. ha-1 compared with those treated with 73.1 g a.i. ha-1. This is the first field study to evaluate the indaziflam dissipation in future, phytotoxic effects of indaziflam should be studied under field conditions.

  14. Effects of oil content on the sensory, textural, and physical properties of pecan butter (Carya illinoinensis).

    Science.gov (United States)

    Wagener, Emily A; Kerr, William L

    2017-10-20

    It has been difficult to produce acceptable pecan butters as the high oil content results in a product that flows and separates too easily. The objective of this work was to create pecan butters with varying oil levels (50-70%) and determine which would give the most acceptable product. Consumers rated pecan butters with 55-60% oil the most acceptable, whether roasted or not. Acceptability varied most in terms of texture and spreadability, but not flavor. Under large deformation firmness varied from 51.8 g (70% oil) to 4,880 g (50%) oil, while "spreadability" ranged from 19.2 to 7748 (g/s). Samples with 70% oil had the lowest viscosity and were Newtonian. Pecan butters with 50-55% oil had high viscosity and were shear thinning. Yield stress decreased with oil content, ranging from 0.014 to 500 Pa. The storage modulus (G') increased from ∼7 Pa for samples with 70% oil up to 260,000 Pa for those with 50% oil. In conjunction, tan δ decreased from 1 to 0.07, showing the products take on much more solid-like behavior as oil is removed. In conclusion, the rheological properties of pecan butter were quite sensitive to the amount of oil in the product. Differences in acceptability were primarily due to "texture" and "spreadability," suggesting there is a limited range of firmness and spreadability that consumers will deem acceptable. There has been considerable demand for butters and spreads made from a variety of culinary nuts. Pecans generally have too much oil (∼70%) to make a product with proper consistency and stability. In this study, some of the oil was removed to overcome this problem. It was found that pecan butter with 55-60% oil was most acceptable to consumers and with the level of firmness, yield stress, and spreadability most similar to commercial nut butters. The oil was relatively simple to remove from unroasted nuts, thus manufacturers could easily produce more acceptable pecan butter for the market. © 2017 Wiley Periodicals, Inc.

  15. Bidirectional reflectance effects derived from ASAS imagery of a pecan orchard

    Science.gov (United States)

    Staenz, Karl; Gauthier, Robert P.; Teillet, Phil M.; Williams, Daniel J.

    1993-09-01

    Bidirectional reflectance factors (BRF) for a pecan orchard have been studied using Advanced Solid-State Array Spectrometer (ASAS) data acquired in the solar principal plane at altitudes of 2300 m and 5300 m above ground. In particular, the angular dependency of the BRF of different targets such as sunlit and shaded portions of the pecan tree, orchard floor, and soil (road) have been studied for viewing directions between -45 degrees and +45 degrees. The results indicate in general an increasing reflectance from the forward scattering direction to the backscattering direction. In addition, an increase in pixel size has significant effects on the surface BRFs.

  16. Dyson shells: a retrospective

    Science.gov (United States)

    Bradbury, Robert J.

    2001-08-01

    More than 40 years have passed since Freeman Dyson suggested that advanced technological civilizations are likely to dismantle planets in their solar systems to harvest all of the energy their stars wastefully radiate into space. Clearly this was an idea that was ahead of its time. Since that time, dozens of SETI searches have been conducted and almost all of them have focused their attention on stars which by definition cannot be the advanced civilizations that Dyson envisioned. I will review the data that created the confusion between Dyson spheres and Dyson shells. The sources that disprove Dyson spheres while still allowing Dyson shells will be discussed. The use of outmoded ideas that have biased the few searches for Dyson Shells that have occurred will be pointed out. An update of the concept of Dyson shells to include our current knowledge of biotechnology, nanotechnology and computer science will be explored. Finally, an approach to setting limits on the abundance of Dyson shells in our galaxy using existing optical astronomical data and future optical satellites will be proposed.

  17. Transcriptome analysis of pecan seeds at different developing stages and identification of key genes involved in lipid metabolism.

    Science.gov (United States)

    Xu, Zheng; Ni, Jun; Shah, Faheem Afzal; Wang, Qiaojian; Wang, Zhaocheng; Wu, Lifang; Fu, Songling

    2018-01-01

    Pecan is an economically important nut crop tree due to its unique texture and flavor properties. The pecan seed is rich of unsaturated fatty acid and protein. However, little is known about the molecular mechanisms of the biosynthesis of fatty acids in the developing seeds. In this study, transcriptome sequencing of the developing seeds was performed using Illumina sequencing technology. Pecan seed embryos at different developmental stages were collected and sequenced. The transcriptomes of pecan seeds at two key developing stages (PA, the initial stage and PS, the fast oil accumulation stage) were also compared. A total of 82,155 unigenes, with an average length of 1,198 bp from seven independent libraries were generated. After functional annotations, we detected approximately 55,854 CDS, among which, 2,807 were Transcription Factor (TF) coding unigenes. Further, there were 13,325 unigenes that showed a 2-fold or greater expression difference between the two groups of libraries (two developmental stages). After transcriptome analysis, we identified abundant unigenes that could be involved in fatty acid biosynthesis, degradation and some other aspects of seed development in pecan. This study presents a comprehensive dataset of transcriptomic changes during the seed development of pecan. It provides insights in understanding the molecular mechanisms responsible for fatty acid biosynthesis in the seed development. The identification of functional genes will also be useful for the molecular breeding work of pecan.

  18. Long-term above-ground biomass production in a red oak-pecan agroforestry system

    Science.gov (United States)

    Agroforestry systems have widely been recognized for their potential to foster long-term carbon sequestration in woody perennials. This study aims to determine the above-ground biomass in a 16-year-old red oak (Quercus rubra) - pecan (Carya illinoinensis) silvopastoral planting (141 and 53 trees ha-...

  19. Phenological responses of juvenile pecan and white oak on an upland site

    Science.gov (United States)

    Pecan (Carya illinoiensis) and white oak (Quercus alba) produce multiple products and wildlife values, but their phenological responses to N fertilization have not been well characterized in an mixed species agroforestry practice. We compared tree height at planting and for six consecutive growing ...

  20. Efficacy of Bordeaux mixture to control pecan scab in large-plot experiments

    Science.gov (United States)

    Venturia effusa causes scab, the most important disease on pecan in the southeastern USA. Organic fungicides have not been widely tested for efficacy against scab on susceptible cultivars. A large-plot experiment was used to test the efficacy of the traditionally-used fungicide against scab, Bordeau...

  1. Evidence for sexual reproduction in Venturia effusa, causal agent of pecan scab

    Science.gov (United States)

    Pecan scab caused by Venturia effusa is widespread across southwest USA and epidemics can result in catastrophic yield loss. Venturia effusa reproduces asexually during the active phase of the disease cycle (spring through summer) with no evidence of a sexual cycle. Yet, genetic diversity among popu...

  2. Phenological responses of juvenile pecan and white oak on an upland site

    Science.gov (United States)

    D. M. Burner; D. K. Brauer; J. L. Snider; C. A. Harrington; P. A. Moore

    2014-01-01

    Pecan (Carya illinoiensis) and white oak (Quercus alba) produce multiple products and wildlife values, but their phenological responses to N fertilization have not been well characterized. We compared tree growth at planting and for six consecutive growing seasons during establishment (2003–2008, Test 1), and determined if...

  3. Application of plant growth regulators mitigates chlorotic foliar injury by the black pecan aphid (Hemiptera: Aphididae).

    Science.gov (United States)

    Cottrell, Ted E; Wood, Bruce W; Ni, Xinzhi

    2010-11-01

    Black pecan aphid, Melanocallis caryaefoliae (Davis) (Hemiptera: Aphididae), feeding elicits localized chlorotic injury to pecan foliage [Carya illinoinensis (Wangenh.) K Koch] and apparent acceleration of leaf senescence and defoliation. The ability of certain plant growth regulators (PGRs) (forchlorfenuron, gibberellic acid and aviglycine) to prevent M. caryaefoliae from triggering pecan leaf chlorosis and senescence-like processes was evaluated on two dates in both 2006 and 2007. Treatments were applied to orchard foliage and used in laboratory leaf-disc bioassays to assess possible reduction in aphid-elicited chlorosis and concomitant effects on aphid mortality and development. Foliage pretreated with forchlorfenuron + gibberellic acid prior to being challenged with aphids resulted in significantly less aphid-elicited chlorosis than did control or aviglycine-treated leaf discs. No PGR affected aphid mortality; however, development time was increased by forchlorfenuron + gibberellic acid in 2006 and by aviglycine + gibberellic acid on one date in 2007. Certain PGRs possess the potential for usage on pecan to protect foliar canopies from M. caryaefoliae via changes in the susceptibility of the host leaf to senescence-like factors being introduced by feeding aphids. This protective effect on host foliage and the associated suppressive effect on development of feeding aphids might also be relevant to pest management programs on other aphid-crop systems in which aphid-elicited chlorosis and senescence-like processes can limit profitability. Published 2010 by John Wiley & Sons, Ltd.

  4. Comparing protection afforded by different organic alternatives to conventional fungicides for reducing scab on pecan

    Science.gov (United States)

    Pecan scab (Venturia effusa) is the major yield-limiting disease in the southeastern USA. Although conventional fungicides are available to manage the disease, there is no comparison of organic methods (organically produced nuts attract a higher price). In 2011, 2012, 2014, 2015 and 2016 trees of cv...

  5. Pecan Research and Outreach in New Mexico: Logic Model Development and Change in Communication Paradigms

    Science.gov (United States)

    Sammis, Theodore W.; Shukla, Manoj K.; Mexal, John G.; Wang, Junming; Miller, David R.

    2013-01-01

    Universities develop strategic planning documents, and as part of that planning process, logic models are developed for specific programs within the university. This article examines the long-standing pecan program at New Mexico State University and the deficiencies and successes in the evolution of its logic model. The university's agricultural…

  6. Growth and foliar nitrogen concentrations of interplanted native woody legumes and pecan

    Science.gov (United States)

    J.W. Van Sambeek; Nadia E. Navarrete-Tindall; Kenneth L. Hunt

    2008-01-01

    The interplanting and underplanting of nodulated nitrogen-fixing plants in tree plantings can increase early growth and foliage nitrogen content of hardwoods, especially black walnut and pecan. Recent studies have demonstrated that some non-nodulated woody legumes may be capable of fixing significant levels of atmospheric nitrogen. The following nine nurse crop...

  7. Characterization of Extruded Poly(lactic acid/Pecan Nutshell Biocomposites

    Directory of Open Access Journals (Sweden)

    C. R. Álvarez-Chávez

    2017-01-01

    Full Text Available Pecan nutshells are a solid form of waste obtained from the pecan nut production and they have been explored as an inexpensive filler for incorporation by melt blending into the poly(lactic acid (PLA matrix. The pecan nutshells contain polyphenols, proteins, tannins, sugars, and lipids; some of these components must be released in order to improve adhesion with a polymeric matrix. The physicochemical characterization of the extruded biocomposites of pecan nutshell powder (PNSP at 0, 5, and 7.5% wt. with two treatments (untreated and defatted into PLA is presented in this work. The incorporation of PNSP into the PLA matrix caused a variation in color and density and increased the water absorption. However, some mechanical and thermal parameters of the biocomposites showed a significant decrease. The morphological analysis showed good dispersion and adhesion of the PNSP to the PLA matrix. Based on the results of the characterization, biocomposites formulated with defatted PNSP have a potential to be used as sustainable fillers in PLA biocomposites. These biocomposites have a potential application as food containers, packaging trays, or disposable items.

  8. Challenges of managing disease in tall orchard trees – pecan scab, a case study

    Science.gov (United States)

    Managing disease in tall orchard trees presents unique issues not found in relatively shorter horticultural and agronomic crops, simply due to height. Pecan scab (caused by Fusicladium effusum [G. Winter] Seyran et al.) is used as an example of a major disease of one of the tallest orchard crops in ...

  9. Flavonoids, alkali earth and rare earth elements affect germination of pecan pollen

    Science.gov (United States)

    The factors regulating pecan [Carya illinoinensis (Wangenh.) K. Koch] pollen grain germination on receptive stigmatic flower surfaces in vivo or in vitro in pollen viability assays are poorly understood. While there are many potential regulating factors, there is evidence for involvement of flavonol...

  10. The PEcAn Project: Model-Data Ecoinformatics for the Observatory Era

    Science.gov (United States)

    Dietze, M. C.; LeBauer, D. S.; Davidson, C. D.; Desai, A. R.; Kooper, R.; McHenry, K.; Mulrooney, P.

    2011-12-01

    The fundamental questions about how terrestrial ecosystems will respond to climate change are straightforward and well known, yet a small number of important gaps separate the information we have gathered from the understanding required to inform policy and management. A critical gap is that no one data source provides a complete picture of the terrestrial biosphere, and therefore multiple data sources must be integrated in a sensible manner. Process-based models represent an ideal framework for this synthesis, but to date model-data synthesize has only made use of a subset of the available data types, and remains inaccessible to much of the scientific community, largely due to the daunting ecoinformatics challenges. The Predictive Ecosystem Analyzer (PEcAn) is an open-source scientific workflow system and ecoinformatics toolbox that manages the flow of information in and out of regional-scale terrestrial biosphere models, facilitates formal data assimilation, and enables more effective feedbacks between models and field research. PEcAn makes complex analyses transparent, repeatable, and accessible to a diverse array of researchers. PEcAn is not model specific, but rather encapsulates any ecosystem model within a set of standardized input and output modules. Herein we demonstrate PEcAn's ability to automate many of the tasks involved in modeling by gathering and processing a diverse arrays of data sets, initiating ensembles of model runs, visualizing output, and comparing models to observations. PEcAn employs a fully Bayesian approach to model parameterization and the estimation of ecosystem pools and fluxes that allows a straightforward propagation of uncertainties into analyses and forecasts. This approach also makes possible the synthesis of a diverse array of data types operating at different spatial and temporal scales and to easily update predictions as new information becomes available. We also demonstrate PEcAn's ability to iteratively synthesize

  11. Shell supports

    DEFF Research Database (Denmark)

    Almegaard, Henrik

    2004-01-01

    A new statical and conceptual model for membrane shell structures - the stringer system - has been found. The principle was first published at the IASS conference in Copenhagen (OHL91), and later the theory has been further developed (ALMO3)(ALMO4). From the analysis of the stringer model it can...... be concluded that all membrane shells can be described by a limited number of basic configurations of which quite a few have free edges....

  12. Microrganismos associados a frutos de diferentes cultivares de noz Pecan Microorganisms associated with fruits of different cultivars of Pecan nut

    Directory of Open Access Journals (Sweden)

    Nádia Izumi Terabe

    2008-04-01

    Full Text Available O conhecimento do comportamento natural da nogueira Pecan às principais doenças é de suma importância para o estabelecimento do planejamento da implantação da cultura. O controle fitossanitário e tratos culturais devem ser realizados de modo a não comprometerem a qualidade do produto final, as amêndoas. Foram avaliadas nozes produzidas na safra de 2005 e oriundas de Uraí-PR, pelas cultivares Burkett, Frotscher e Moneymaker, para identificar e quantificar os microrganismos associados à amêndoas e cascas dos frutos, bem como observar diferenças entre organismos colonizadores das cultivares. Os frutos foram avaliados na pós-colheita, aos trinta dias de armazenamento em ambiente, através da metodologia do papel de filtro, sendo submetidos ou não à assepsia superficial. O fungo Cladosporium caryigenum, promotor da rancificação das amêndoas foi observado, em amêndoas e cascas, nas cultivares Burkett, Frotscher e Moneymaker; Fusarium sp., foi encontrado em porcentuais elevados, tanto em amêndoas quanto em cascas das três cultivares estudadas; Cephalothecium roseum, causador do mofo róseo em amêndoas, na cultivar Frotscher. Aspergillus sp. e Penicillium sp., causadores de emboloramento e produtores de aflotoxinas foram observados em porcentuais representativos, em amêndoas da cultivar Frotscher e em amêndoas e cascas das cultivares Frotscher, Burkett e Moneymaker, respectivamente. Os maiores porcentuais de perda do rendimento foram observados na cultivar Burkett, por causa da incidência de Colletotrichum sp., causador da antracnose em amêndoas, que acarreta escurecimento e deterioração do produto final, levando-o ao descarte.The knowledgement of the natural behavior of the main diseases of Pecan nut is of utmost importance for the stablishment of an implantation plan for that culture. The phytosanitary control and cultural treatments should be performed in order not to change the quality of the final product. Nuts harvest

  13. Cloning and characterization of an 11S legumin, Car i 4, a major allergen in pecan.

    Science.gov (United States)

    Sharma, Girdhari M; Irsigler, Andre; Dhanarajan, Pushparani; Ayuso, Rosalia; Bardina, Luda; Sampson, Hugh A; Roux, Kenneth H; Sathe, Shridhar K

    2011-09-14

    Among tree nut allergens, pecan allergens remain to be identified and characterized. The objective was to demonstrate the IgE-binding ability of pecan 11S legumin and characterize its sequential IgE-binding epitopes. The 11S legumin gene was amplified from a pecan cDNA library and expressed as a fusion protein in Escherichia coli. The native 11S legumin in pecan extract was identified by mass spectrometry/mass spectrometry (MS/MS). Sequential epitopes were determined by probing the overlapping peptides with three serum pools prepared from different patients' sera. A three-dimensional model was generated using almond legumin as a template and compared with known sequential epitopes on other allergenic tree nut homologues. Of 28 patients tested by dot blot, 16 (57%) bound to 11S legumin, designated Car i 4. MS/MS sequencing of native 11S legumin identified 33 kDa acidic and 20-22 kDa basic subunits. Both pecan and walnut seed protein extracts inhibited IgE binding to recombinant Car i 4, suggesting cross-reactivity with Jug r 4. Sequential epitope mapping results of Car i 4 revealed weak, moderate, and strong reactivity of serum pools against 10, 5, and 4 peptides, respectively. Seven peptides were recognized by all three serum pools, of which two were strongly reactive. The strongly reactive peptides were located in three discrete regions of the Car i 4 acidic subunit sequence (residues 118-132, 208-219, and 238-249). Homology modeling of Car i 4 revealed significant overlapping regions shared in common with other tree nut legumins.

  14. Population Genetic Structure of Venturia effusa, Cause of Pecan Scab, in the Southeastern United States.

    Science.gov (United States)

    Bock, Clive H; Hotchkiss, Michael W; Young, Carolyn A; Charlton, Nikki D; Chakradhar, Mattupalli; Stevenson, Katherine L; Wood, Bruce W

    2017-05-01

    Venturia effusa is the most important pathogen of pecan in the southeastern United States. Little information exists on the population biology and genetic diversity of the pathogen. A hierarchical sampling of 784 isolates from 63 trees in 11 pecan orchards in the southeastern United States were screened against a set of 30 previously characterized microsatellite markers. Populations were collected from Georgia (n = 2), Florida (n = 1), Alabama (n = 2), Mississippi (n = 1), Louisiana (n = 1), Illinois (n = 1), Oklahoma (n = 1), Texas (n = 1), and Kansas (n = 1). Clonality was low in all orchard populations (≤10.1% of isolates), and there were consistently high levels of genotypic diversity (Shannon-Weiner's index = 3.49 to 4.59) and gene diversity (Nei's measure = 0.513 to 0.713). Analysis of molecular variance showed that, although 81% of genetic diversity occurred at the scale of the individual tree, 16% occurred between orchards and only 3% between trees within orchards. All populations could be differentiated from each other (P = 0.01), and various cluster analyses indicated that some populations were more closely related compared with other pairs of populations. This is indicative of some limited population differentiation in V. effusa in the southeastern United States. Bayesian and nearest-neighbor methods suggested eight clusters, with orchards from Georgia and Florida being grouped together. A minimum spanning tree of all 784 isolates also indicated some isolate identification with source population. Linkage disequilibrium was detected in all but one population (Kansas), although 8 of the 11 populations had pecan and pecan scab, which is that V. effusa became an issue on cultivated pecan in the last approximately 120 years (recent population expansion). Recently reported mating type genes and the sexual stage of this fungus may help explain the observed population characteristics, which bear a strong resemblance to those of other well

  15. Cloning and characterization of 2S albumin, Car i 1, a major allergen in pecan.

    Science.gov (United States)

    Sharma, Girdhari M; Irsigler, Andre; Dhanarajan, Pushparani; Ayuso, Rosalia; Bardina, Luda; Sampson, Hugh A; Roux, Kenneth H; Sathe, Shridhar K

    2011-04-27

    Although pecans are associated with IgE-mediated food allergies, the allergens responsible remain to be identified and characterized. The 2S albumin gene was amplified from the pecan cDNA library. Dot-blots were used to screen the recombinant protein with pecan allergic patients' serum. The affinity purified native protein was analyzed by Edman sequencing and mass spectrometry/mass spectrometry (MS/MS) analysis. Cross-reactivity with walnut was determined by inhibition enzyme-linked immunosorbent assay (ELISA). Sequential epitopes were determined by probing the overlapping peptides with three different patients' serum pool. The 3-dimensional homology model was generated, and the locations of the pecan epitopes were compared with those of known sequential epitopes on other allergenic tree nut homologues. Of 28 patients tested by dot-blot, 22 (79%) bound to 2S albumin, designated as Car i 1. Edman sequencing and the MS/MS sequencing of native 2S albumin confirmed the identity of recombinant (r) Car i 1. Both pecan and walnut protein extracts inhibited the IgE-binding to rCar i 1. Sequential epitope mapping indicated weak, moderate, and strong reactivity against 12, 7, and 5 peptides, respectively. Of the 11 peptides recognized by all serum pools, 5 peptides were strongly reactive and located in 3 discrete regions of the Car i 1 (amino acids 43-57, 67-78, and 106-120). Three-dimensional modeling revealed IgE-reactive epitopes to be solvent accessible and share significant homology with other tree nuts providing a possible basis for previously observed cross-reactivity.

  16. Biochemical characterization of soluble proteins in pecan [Carya illinoinensis (Wangenh.) K. Koch].

    Science.gov (United States)

    Venkatachalam, Mahesh; Roux, Kenneth H; Sathe, Shridhar K

    2008-09-10

    Pecans (cv. Desirable) contained approximately 10% protein on a dry weight basis. The minimum nitrogen solubility (5.9-7.5%) at 0.25-0.75 M trichloroacetic acid represented the nonprotein nitrogen. Among the solvents assessed for protein solubilization, 0.1 M NaOH was the most effective, while borate saline buffer (pH 8.45) was judged to be optimal for protein solubilization. The protein solubility was minimal in the pH range of 3-7 and significantly increased on either side of this pH range. Increasing the NaCl concentration from 0 to 4 M significantly improved ( approximately 8-fold increase) protein solubilization. Following Osborne protein fractionation, the alkali-soluble glutelin fraction (60.1%) accounted for a major portion of pecan proteins followed by globulin (31.5%), prolamin (3.4%), and albumin (1.5%), respectively. The majority of pecan polypeptides were in the molecular mass range of 12-66 kDa and in the pI range of 4.0-8.3. The pecan globulin fraction was characterized by the presence of several glycoprotein polypeptides. Lysine was the first limiting essential amino acid in the defatted flour, globulin, prolamin, and alkaline glutelin fractions. Leucine and tryptophan were the first limiting essential amino acids in albumin and acid glutelin fractions, respectively. Rabbit polyclonal antibodies detected a range of pecan polypeptides in the 12-60 kDa range, of which the globulin fraction contained the most reactive polypeptides.

  17. Evidence for the presence of an endosymbiont in the Pecan Scab pathogen Venturia effusa (basyonym: Fusicladium effusum)

    Science.gov (United States)

    Aims: To determine whether Venturia effusa (basyonym: Fusicladium effusum) the causative fungal agent of Pecan Scab harbors a bacterial symbiont. Methods and Results: Beginning with monoconidial isolates, V. effusa was maintained on potato dextrose agar amended with antibiotics (chloramphenicol 10...

  18. One-step multiplex PCR method for the determination of pecan and Brazil nut allergens in food products.

    Science.gov (United States)

    Hubalkova, Zora; Rencova, Eva

    2011-10-01

    A one-step polymerase chain reaction (PCR) method for the simultaneous detection of the major allergens of pecan and Brazil nuts was developed. Primer pairs for the amplification of partial sequences of genes encoding the allergens were designed and tested for their specificity on a range of food components. The targeted amplicon size was 173 bp of Ber e 1 gene of Brazil nuts and 72 bp of vicilin-like seed storage protein gene in pecan nuts. The primer pair detecting the noncoding region of the chloroplast DNA was used as the internal control of amplification. The intrinsic detection limit of the PCR method was 100 pg mL(-1) pecan or Brazil nuts DNA. The practical detection limit was 0.1% w/w (1 g kg(-1)). The method was applied for the investigation of 63 samples with the declaration of pecans, Brazil nuts, other different nut species or nuts generally. In 15 food samples pecans and Brazil nuts allergens were identified in the conformity with the food declaration. The presented multiplex PCR method is specific enough and can be used as a fast approach for the detection of major allergens of pecan or Brazil nuts in food. Copyright © 2011 Society of Chemical Industry.

  19. Influence of Pecan Nut Pretreatment on the Physical Quality of Oil Bodies

    Directory of Open Access Journals (Sweden)

    Pujuan Zhang

    2017-01-01

    Full Text Available A supply of pure, intact oil bodies is essential for carrying out morphological and biochemical studies of these plant organelles and exploring their application. Preparation requires a carefully controlled breakage of plant cells, followed by separation of the oil bodies from cytoplasm and cell debris. This paper focuses on the recovery and characterisation of oil bodies from pecan nuts where no work has been published to date. The results showed that soaking softens the nut tissue and appears to reduce the damage to oil bodies during grinding and centrifugal force must be carefully selected to minimise oil bodies damage on recovery. A 24 h soaking time coupled with a 5500 RCF recovery force allows for the recovery of intact pecan nut oil bodies.

  20. Pecan Street Smart Grid Extension Service at the University of Texas

    Energy Technology Data Exchange (ETDEWEB)

    McCracken, Brewster [Pecan Street Project, Inc., Austin, TX (United States)

    2014-02-11

    Through funding from the Department of Energy’s Electricity Delivery and Reliability Office, Pecan Street Inc., in partnership with Austin Energy and Oncor, developed and tested third- party data access platforms and services for Green Button offerings and for other home energy use data providers. As more utilities seek to offer Green Button-compliant data to their customers, the question continually arises of how this data can be used to help customers better manage their energy use.

  1. Nickel deficiency disrupts metabolism of ureides, amino acids, and organic acids of young pecan foliage.

    Science.gov (United States)

    Bai, Cheng; Reilly, Charles C; Wood, Bruce W

    2006-02-01

    The existence of nickel (Ni) deficiency is becoming increasingly apparent in crops, especially for ureide-transporting woody perennials, but its physiological role is poorly understood. We evaluated the concentrations of ureides, amino acids, and organic acids in photosynthetic foliar tissue from Ni-sufficient (Ni-S) versus Ni-deficient (Ni-D) pecan (Carya illinoinensis [Wangenh.] K. Koch). Foliage of Ni-D pecan seedlings exhibited metabolic disruption of nitrogen metabolism via ureide catabolism, amino acid metabolism, and ornithine cycle intermediates. Disruption of ureide catabolism in Ni-D foliage resulted in accumulation of xanthine, allantoic acid, ureidoglycolate, and citrulline, but total ureides, urea concentration, and urease activity were reduced. Disruption of amino acid metabolism in Ni-D foliage resulted in accumulation of glycine, valine, isoleucine, tyrosine, tryptophan, arginine, and total free amino acids, and lower concentrations of histidine and glutamic acid. Ni deficiency also disrupted the citric acid cycle, the second stage of respiration, where Ni-D foliage contained very low levels of citrate compared to Ni-S foliage. Disruption of carbon metabolism was also via accumulation of lactic and oxalic acids. The results indicate that mouse-ear, a key morphological symptom, is likely linked to the toxic accumulation of oxalic and lactic acids in the rapidly growing tips and margins of leaflets. Our results support the role of Ni as an essential plant nutrient element. The magnitude of metabolic disruption exhibited in Ni-D pecan is evidence of the existence of unidentified physiological roles for Ni in pecan.

  2. Silicon ribbon technology assessment 1978-1986 - A computer-assisted analysis using PECAN

    Science.gov (United States)

    Kran, A.

    1978-01-01

    The paper presents a 1978-1986 economic outlook for silicon ribbon technology based on the capillary action shaping technique. The outlook is presented within the framework of two sets of scenarios, which develop strategy for approaching the 1986 national energy capacity cost objective of $0.50/WE peak. The PECAN (Photovoltaic Energy Conversion Analysis) simulation technique is used to develop a 1986 sheet material price ($50/sq m) which apparently can be attained without further scientific breakthrough.

  3. Networked Thermodynamic Boundary Layer Profiling with AERIs during the PECAN Field Campaign

    Science.gov (United States)

    Gero, P. J.; Turner, D. D.; Hackel, D.; Phillips, C.; Smith, N.; Wagner, T.

    2015-12-01

    The Plains Elevated Convection at Night (PECAN) campaign was a large-scale field experiment in the Great Plains region of the U.S. that was conducted in June-July 2015. Nocturnal storms provide the majority of the precipitation in the Great Plains, yet the initiation and evolution of nocturnal convection is not understood to the same level as daytime surface-based convection, and thus provides significant challenges for operational weather forecasters. PECAN's objectives were to study elevated nocturnal convection initiation and the lifecycle of nocturnal convection. Specific research areas that were studied were the evolution of mesoscale convective systems, the structure and evolution of nocturnal low-level jets, atmospheric bores, and elevated convection initiation. A broad range of fixed and mobile observing systems were deployed by several agencies and organizations in a domain centered around Kansas. The Atmospheric Emitted Radiance Interferometer (AERI) is a ground-based instrument that measures downwelling infrared radiance from the atmosphere. AERI observations can be used to obtain vertical profiles of tropospheric temperature and water vapor in the lowest 3 km of the troposphere, as well as measurements of the concentration of various trace gases and microphysical and optical properties of clouds and aerosols. A network of eight AERIs was deployed in the domain during PECAN, with six at fixed sites and two in mobile facilities. One of the goals of the campaign was a demonstration of the use of real-time high-temporal-resolution boundary layer profiles from the network of AERIs for characterizing the mesoscale environment and its evolution during the weather events sampled during PECAN. If successful, a future network could be implemented across CONUS and thermodynamic profiles in the boundary layer data assimilated to help improve numerical weather prediction. We present an overview of the AERI deployments, a summary of the technique used to retrieve

  4. Zinc deficiency in field-grown pecan trees: changes in leaf nutrient concentrations and structure.

    Science.gov (United States)

    Ojeda-Barrios, Dámaris; Abadía, Javier; Lombardini, Leonardo; Abadía, Anunciación; Vázquez, Saúl

    2012-06-01

    Zinc (Zn) deficiency is a typical nutritional disorder in pecan trees [Carya illinoinensis (Wangenh.) C. Koch] grown under field conditions in calcareous soils in North America, including northern Mexico and south-western United States. The aim of this study was to assess the morphological and nutritional changes in pecan leaves affected by Zn deficiency as well as the Zn distribution within leaves. Zinc deficiency led to decreases in leaf chlorophyll concentrations, leaf area and trunk cross-sectional area. Zinc deficiency increased significantly the leaf concentrations of K and Ca, and decreased the leaf concentrations of Zn, Fe, Mn and Cu. All nutrient values found in Zn-deficient leaves were within the sufficiency ranges, with the only exception of Zn, which was approximately 44, 11 and 9 µg g(-1) dry weight in Zn-sufficient, moderately and markedly Zn-deficient leaves, respectively. Zinc deficiency led to decreases in leaf thickness, mainly due to a reduction in the thickness of the palisade parenchyma, as well as to increases in stomatal density and size. The localisation of Zn was determined using the fluorophore Zinpyr-1 and ratio-imaging technique. Zinc was mainly localised in the palisade mesophyll area in Zn-sufficient leaves, whereas no signal could be obtained in Zn-deficient leaves. The effects of Zn deficiency on the leaf characteristics of pecan trees include not only decreases in leaf chlorophyll and Zn concentrations, but also a reduction in the thickness of the palisade parenchyma, an increase in stomatal density and pore size and the practical disappearance of Zn leaf pools. These characteristics must be taken into account to design strategies to correct Zn deficiency in pecan tree in the field. Copyright © 2012 Society of Chemical Industry.

  5. Numerical Modeling of Water Fluxes in the Root Zone of Irrigated Pecan

    Science.gov (United States)

    Shukla, M. K.; Deb, S.

    2010-12-01

    Information is still limited on the coupled liquid water, water vapor, heat transport and root water uptake for irrigated pecan. Field experiments were conducted in a sandy loam mature pecan field in Las Cruces, New Mexico. Three pecan trees were chosen to monitor diurnal soil water content under the canopy (approximately half way between trunk and the drip line) and outside the drip line (bare spot) along a transect at the depths of 5, 10, 20, 40, and 60 cm using TDR sensors. Soil temperature sensors were installed at an under-canopy locations and bare spot to monitor soil temperature data at depths of 5, 10, 20, and 40 cm. Simulations of the coupled transport of liquid water, water vapor, and heat with and without root water uptake were carried out using the HYDRUS-1D code. Measured soil hydraulic and thermal properties, continuous meteorological data, and pecan characteristics, e.g. rooting depth, leaf area index, were used in the model simulations. Model calibration was performed for a 26-day period from DOY 204 through DOY 230, 2009 based on measured soil water content and soil temperature data at different soil depths, while the model was validated for a 90-day period from DOY 231 through DOY 320, 2009 at bare spot. Calibrated parameters were also used to apply the model at under-canopy locations for a 116-day period from DOY 204 to 320. HYDRUS-1D simulated water contents and soil temperatures correlated well with the measured data at each depth. Numerical assessment of various transport mechanisms and quantitative estimates of isothermal and thermal water fluxes with and without root water uptake in the unsaturated zone within canopy and bare spot is in progress and will be presented in the conference.

  6. Contact dermatitis following sustained exposure to pecans (Carya illinoensis): a case report.

    Science.gov (United States)

    Joyce, Kathleen M; Boyd, Jason; Viernes, Jay L

    2006-04-01

    Type I hypersensitivity reactions following ingestion of peanuts and tree nuts are well characterized. Cutaneous hypersensitivity reactions are less well characterized, yet they remain the second most common reaction pattern to contact with or ingestion of such nuts. We present a case of a patient who experienced an acute vesicular cutaneous reaction after prolonged contact with pecans. This case illustrates the salient features of contact dermatitis and serves as a reminder that contact with allergenic foods can lead to hypersensitivity reactions.

  7. Estimating the actual ET from a pecan farm using the OPEC energy-balance and Penman- Monteith methods

    Science.gov (United States)

    Debele, B.; Bawazir, S. A.

    2006-12-01

    Accurate estimation of ET from field crops/orchards is the basis for better irrigation water management. In areas like Mesilla Valley, NM, where water is scarce, it is even more important to precisely determine the crop ET. An OPEC energy balance system was run for 117 days (June 22 October 14, 2001) in a matured pecan farm at Mesilla Valley, NM. The actual evapotranspiration (ET) from pecan orchards was determined from the surface energy balance as a residual, having measured the net radiation, soil heat flux, and sensible heat components using the OPEC method. Since pecans are large trees, we have also examined the effect of including thermal energies stored in the air (Ga) and plant canopy (Gc), on top of the commonly used thermal energy stored in the soil (Gs), on surface energy balance, and hence ET. The results indicate that incorporating thermal energies stored in the air and canopy has a significant effect on total energy storage for shorter temporal resolutions, such as 30-minutes and an hour. Conversely, for longer temporal resolutions (e.g., diurnal and monthly averages), the effect of including thermal energies stored in the air and vegetation on total thermal energy storage is negligible. Our results also showed that the bulk of the total thermal energy storage (G = Gs + Ga + Gc) in the surface energy balance was stored in the soil (Gs). In addition, we have also determined the crop coefficient (Kc) of pecan by combining the actual ET obtained from the OPEC method and potential ET (ET0) calculated using weather data in the surrounding area. Our average pecan Kc values were comparable with the ones reported by other researchers using different methods. We conclude that the OPEC energy balance method can be used to calculate Kc values for pecan whereby farmers and extension agents use the calculated Kc values in combination with ET0 to determine the consumptive use of pecan trees.

  8. Morphological and molecular characterization of Fusarium spp pathogenic to pecan tree in Brazil.

    Science.gov (United States)

    Lazarotto, M; Milanesi, P M; Muniz, M F B; Reiniger, L R S; Beltrame, R; Harakava, R; Blume, E

    2014-11-11

    The occurrence of Fusarium spp associated with pecan tree (Carya illinoinensis) diseases in Brazil has been observed in recent laboratory analyses in Rio Grande do Sul State. Thus, in this study, we i) obtained Fusarium isolates from plants with disease symptoms; ii) tested the pathogenicity of these Fusarium isolates to pecan; iii) characterized and grouped Fusarium isolates that were pathogenic to the pecan tree based on morphological characteristics; iv) identified Fusarium spp to the species complex level through TEF-1α sequencing; and v) compared the identification methods used in the study. Fifteen isolates collected from the inflorescences, roots, and seeds of symptomatic plants (leaf necrosis or root rot) were used for pathogenicity tests. Morphological characterization was conducted using only pathogenic isolates, for a total of 11 isolates, based on the mycelial growth rate, sporulation, colony pigmentation, and conidial length and width variables. Pathogenic isolates were grouped based on morphological characteristics, and molecular characterization was performed by sequencing TEF-1α genes. Pathogenic isolates belonging to the Fusarium chlamydosporum species complex, Fusarium graminearum species complex, Fusarium proliferatum, and Fusarium oxysporum were identified based on the TEF-1α region. Morphological characteristics were used to effectively differentiate isolates and group the isolates according to genetic similarity, particularly conidial width, which emerged as a key morphological descriptor in this study.

  9. Chemical Characterization of Major and Minor Compounds of Nut Oils: Almond, Hazelnut, and Pecan Nut

    Directory of Open Access Journals (Sweden)

    Gabriel D. Fernandes

    2017-01-01

    Full Text Available The aim of this work was to characterize the major and minor compounds of laboratory-extracted and commercial oils from sweet almond, hazelnut, and pecan nut. Oils from sweet almond, hazelnut, and pecan nut were obtained by means of an expeller system, while the corresponding commercial oils were provided from Vital Âtman (BR. The contents of triacylglycerols, fatty acids, aliphatic and terpenic alcohols, desmethyl-, methyl-, and dimethylsterols, squalene, and tocopherols were determined. Oleic, palmitic, and linoleic acids were the main fatty acids. Desmethylsterols were the principal minor compounds with β-sitosterol being the most abundant component. Low amounts of aliphatic and terpenic alcohols were also found. The major tocopherol in hazelnut and sweet almond oils was α-tocopherol, whereas γ-tocopherol prevailed in pecan nut oil. Principal component analysis made it possible for us to differentiate among samples, as well as to distinguish between commercial and laboratory-extracted oils. Heatmap highlighted the main variables featuring each sample. Globally, these results have brought a new approach on nut oil characterization.

  10. Pecan growth under different soil preparation and hole sizes: coleopterans as bioindicators

    Directory of Open Access Journals (Sweden)

    Jardel Boscardin

    2017-12-01

    Full Text Available The study aimed to evaluate the effects of different soil preparation and hole sizes in an orchard of Carya illinoinensis pecan (Wangenh. K. Koch (Juglandaceae by the Order Coleoptera fauna. A pecan orchard was established in spacing 7 m x 7 m, in Santa Maria, Rio Grande do Sul State, Brazil in randomized block design, with five blocks and four treatments, using: small pit 20 m x 60 cm (Cp; more harrowing subsoiler and small pit (Scp; rotary hoe and small pit (Ecp; and large pit 40 m x 60 cm (Cg. From March 2014 to November 2015, eight samples were taken from Coleoptera fauna, one per season, with four pitfall traps distributed in each treatment and the surrounding area, totaling 100 samples per collection. The Ecp treatment had the lowest diversity values and evenness for Coleoptera fauna, while the Cp and Cg treatments presented the highest indices. The species Diloboderus abderus (Sturm was as very common. It was concluded that Cg treatment does not interfere with coleopteran and promotes the highest growth in diameter of pecan plants.

  11. The pecan provenance collection at Byron GA – a unique resource for the long-term survival of the US industry

    Science.gov (United States)

    Pecan scab, caused by Fusicladium effusum is the most destructive disease of pecan in Georgia and elsewhere in the southeastern US. Understanding patterns of natural variation is vital for improving any crop species. It is the natural variation that provides traits of potential value to a crop and t...

  12. A brief review of some pathology research supported by the Georgia Commodity Commission for Pecans at the USDA-ARS, Byron

    Science.gov (United States)

    With the changes currently taking place nationally in the pecan industry, and the production issues faced specifically by growers in Georgia and elsewhere in the southeastern region, the pathology research projects funded by the Georgia Commodity Commission for Pecans (CC) are reviewed. The results ...

  13. Cumulative impact of a clover cover crop on the persistance and efficancy of Beauveria bassiana in suppressing the pecan weevil (Coleoptera: Curculionidae)

    Science.gov (United States)

    Curculio caryae (Horn), is a key pest of pecans. Endemic levels of the entomopathogenic fungus Beauveria bassiana can occur in pecan orchards and contribute to natural control of C. caryae. Commercial formulations of the fungus can also be applied for suppression of C. caryae. We hypothesized tha...

  14. The PEcAn Project: Accessible Tools for On-demand Ecosystem Modeling

    Science.gov (United States)

    Cowdery, E.; Kooper, R.; LeBauer, D.; Desai, A. R.; Mantooth, J.; Dietze, M.

    2014-12-01

    Ecosystem models play a critical role in understanding the terrestrial biosphere and forecasting changes in the carbon cycle, however current forecasts have considerable uncertainty. The amount of data being collected and produced is increasing on daily basis as we enter the "big data" era, but only a fraction of this data is being used to constrain models. Until we can improve the problems of model accessibility and model-data communication, none of these resources can be used to their full potential. The Predictive Ecosystem Analyzer (PEcAn) is an ecoinformatics toolbox and a set of workflows that wrap around an ecosystem model and manage the flow of information in and out of regional-scale TBMs. Here we present new modules developed in PEcAn to manage the processing of meteorological data, one of the primary driver dependencies for ecosystem models. The module downloads, reads, extracts, and converts meteorological observations to Unidata Climate Forecast (CF) NetCDF community standard, a convention used for most climate forecast and weather models. The module also automates the conversion from NetCDF to model specific formats, including basic merging, gap-filling, and downscaling procedures. PEcAn currently supports tower-based micrometeorological observations at Ameriflux and FluxNET sites, site-level CSV-formatted data, and regional and global reanalysis products such as the North American Regional Reanalysis and CRU-NCEP. The workflow is easily extensible to additional products and processing algorithms.These meteorological workflows have been coupled with the PEcAn web interface and now allow anyone to run multiple ecosystem models for any location on the Earth by simply clicking on an intuitive Google-map based interface. This will allow users to more readily compare models to observations at those sites, leading to better calibration and validation. Current work is extending these workflows to also process field, remotely-sensed, and historical

  15. Dynamic Changes in Phenolics and Antioxidant Capacity during Pecan (Carya illinoinensis Kernel Ripening and Its Phenolics Profiles

    Directory of Open Access Journals (Sweden)

    Xiaodong Jia

    2018-02-01

    Full Text Available Pecan (Carya illinoinensis kernels have a high phenolics content and a high antioxidant capacity compared to other nuts—traits that have attracted great interest of late. Changes in the total phenolic content (TPC, condensed tannins (CT, total flavonoid content (TFC, five individual phenolics, and antioxidant capacity of five pecan cultivars were investigated during the process of kernel ripening. Ultra-performance liquid chromatography coupled with quadruple time-of-flight mass (UPLC-Q/TOF-MS was also used to analyze the phenolics profiles in mixed pecan kernels. TPC, CT, TFC, individual phenolics, and antioxidant capacity were changed in similar patterns, with values highest at the water or milk stages, lowest at milk or dough stages, and slightly varied at kernel stages. Forty phenolics were tentatively identified in pecan kernels, of which two were first reported in the genus Carya, six were first reported in Carya illinoinensis, and one was first reported in its kernel. The findings on these new phenolic compounds provide proof of the high antioxidant capacity of pecan kernels.

  16. Comparison of Oil Content and Fatty Acids Profile of Western Schley, Wichita, and Native Pecan Nuts Cultured in Chihuahua, Mexico

    Directory of Open Access Journals (Sweden)

    L. R. Rivera-Rangel

    2018-01-01

    Full Text Available Two different extraction processes, Soxhlet and ultrasound, were used to obtain the oil extracts of Western Schley, Wichita, and Native pecan nuts cultured in Chihuahua, Mexico. The aspects evaluated in this study were the extraction yield of the processes and fatty acids’ profile of the resulting extracts. Gas chromatography coupled with mass spectrometry (GC-MS was used to identify and determine the composition percentage of fatty acids present in pecan nuts oils extracted. The results obtained show that higher oil extraction yields were obtained by Soxhlet method with hexane (69.90% in Wichita varieties. Wichita, Western Schley, and Native pecan nuts from Chihuahua are rich in PUFA (polyunsaturated fatty acids and MUFA (monounsaturated fatty acids and have low levels of SFA (saturated fatty acids. The predominant fatty acid present in all pecan nuts oils was linoleic acid followed by oleic acid. Myristic acid, palmitic acid, and linolenic acid were also identified in representative quantities. The results from this study suggest that there are statistically significant differences in the chemical composition of the pecan nuts oils extracted from the varieties cultured in Chihuahua, Mexico, and those cultivated in other regions of the world.

  17. A Pecan-Rich Diet Improves Cardiometabolic Risk Factors in Overweight and Obese Adults: A Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Diane L. McKay

    2018-03-01

    Full Text Available Evidence from observational and intervention studies has shown a high intake of tree nuts is associated with a reduced risk of cardiovascular disease (CVD, mortality from type 2 diabetes (T2DM, and all-cause mortality. However, there is limited data regarding their effects on indicators of cardiometabolic risk other than hypercholesterolemia, and little is known about the demonstrable health benefits of pecans (Carya illinoensis (Wangenh. K.Koch. We conducted a randomized, controlled feeding trial to compare the effects of a pecan-rich diet with an isocaloric control diet similar in total fat and fiber content, but absent nuts, on biomarkers related to CVD and T2DM risk in healthy middle-aged and older adults who are overweight or obese with central adiposity. After 4 weeks on a pecan-rich diet, changes in serum insulin, insulin resistance (HOMA-IR and beta cell function (HOMA-β were significantly greater than after the control diet (p < 0.05. Pecan consumption also lowered the risk of cardiometabolic disease as indicated by a composite score reflecting changes in clinically relevant markers. Thus, compared to the control diet, the pecan intervention had a concurrent and clinically significant effect on several relevant markers of cardiometabolic risk.

  18. A Pecan-Rich Diet Improves Cardiometabolic Risk Factors in Overweight and Obese Adults: A Randomized Controlled Trial.

    Science.gov (United States)

    McKay, Diane L; Eliasziw, Misha; Chen, C Y Oliver; Blumberg, Jeffrey B

    2018-03-11

    Evidence from observational and intervention studies has shown a high intake of tree nuts is associated with a reduced risk of cardiovascular disease (CVD), mortality from type 2 diabetes (T2DM), and all-cause mortality. However, there is limited data regarding their effects on indicators of cardiometabolic risk other than hypercholesterolemia, and little is known about the demonstrable health benefits of pecans ( Carya illinoensis (Wangenh.) K.Koch). We conducted a randomized, controlled feeding trial to compare the effects of a pecan-rich diet with an isocaloric control diet similar in total fat and fiber content, but absent nuts, on biomarkers related to CVD and T2DM risk in healthy middle-aged and older adults who are overweight or obese with central adiposity. After 4 weeks on a pecan-rich diet, changes in serum insulin, insulin resistance (HOMA-IR) and beta cell function (HOMA-β) were significantly greater than after the control diet ( p Pecan consumption also lowered the risk of cardiometabolic disease as indicated by a composite score reflecting changes in clinically relevant markers. Thus, compared to the control diet, the pecan intervention had a concurrent and clinically significant effect on several relevant markers of cardiometabolic risk.

  19. Comparison of Oil Content and Fatty Acids Profile of Western Schley, Wichita, and Native Pecan Nuts Cultured in Chihuahua, Mexico

    Science.gov (United States)

    Rivera-Rangel, L. R.; Aguilera-Campos, K. I.; García-Triana, A.; Ayala-Soto, J. G.; Chavez-Flores, D.

    2018-01-01

    Two different extraction processes, Soxhlet and ultrasound, were used to obtain the oil extracts of Western Schley, Wichita, and Native pecan nuts cultured in Chihuahua, Mexico. The aspects evaluated in this study were the extraction yield of the processes and fatty acids' profile of the resulting extracts. Gas chromatography coupled with mass spectrometry (GC-MS) was used to identify and determine the composition percentage of fatty acids present in pecan nuts oils extracted. The results obtained show that higher oil extraction yields were obtained by Soxhlet method with hexane (69.90%) in Wichita varieties. Wichita, Western Schley, and Native pecan nuts from Chihuahua are rich in PUFA (polyunsaturated fatty acids) and MUFA (monounsaturated fatty acids) and have low levels of SFA (saturated fatty acids). The predominant fatty acid present in all pecan nuts oils was linoleic acid followed by oleic acid. Myristic acid, palmitic acid, and linolenic acid were also identified in representative quantities. The results from this study suggest that there are statistically significant differences in the chemical composition of the pecan nuts oils extracted from the varieties cultured in Chihuahua, Mexico, and those cultivated in other regions of the world. PMID:29610686

  20. Dynamic Changes in Phenolics and Antioxidant Capacity during Pecan (Carya illinoinensis) Kernel Ripening and Its Phenolics Profiles.

    Science.gov (United States)

    Jia, Xiaodong; Luo, Huiting; Xu, Mengyang; Zhai, Min; Guo, Zhongren; Qiao, Yushan; Wang, Liangju

    2018-02-16

    Pecan ( Carya illinoinensis ) kernels have a high phenolics content and a high antioxidant capacity compared to other nuts-traits that have attracted great interest of late. Changes in the total phenolic content (TPC), condensed tannins (CT), total flavonoid content (TFC), five individual phenolics, and antioxidant capacity of five pecan cultivars were investigated during the process of kernel ripening. Ultra-performance liquid chromatography coupled with quadruple time-of-flight mass (UPLC-Q/TOF-MS) was also used to analyze the phenolics profiles in mixed pecan kernels. TPC, CT, TFC, individual phenolics, and antioxidant capacity were changed in similar patterns, with values highest at the water or milk stages, lowest at milk or dough stages, and slightly varied at kernel stages. Forty phenolics were tentatively identified in pecan kernels, of which two were first reported in the genus Carya , six were first reported in Carya illinoinensis , and one was first reported in its kernel. The findings on these new phenolic compounds provide proof of the high antioxidant capacity of pecan kernels.

  1. Comparison of Oil Content and Fatty Acids Profile of Western Schley, Wichita, and Native Pecan Nuts Cultured in Chihuahua, Mexico.

    Science.gov (United States)

    Rivera-Rangel, L R; Aguilera-Campos, K I; García-Triana, A; Ayala-Soto, J G; Chavez-Flores, D; Hernández-Ochoa, L

    2018-01-01

    Two different extraction processes, Soxhlet and ultrasound, were used to obtain the oil extracts of Western Schley, Wichita, and Native pecan nuts cultured in Chihuahua, Mexico. The aspects evaluated in this study were the extraction yield of the processes and fatty acids' profile of the resulting extracts. Gas chromatography coupled with mass spectrometry (GC-MS) was used to identify and determine the composition percentage of fatty acids present in pecan nuts oils extracted. The results obtained show that higher oil extraction yields were obtained by Soxhlet method with hexane (69.90%) in Wichita varieties. Wichita, Western Schley, and Native pecan nuts from Chihuahua are rich in PUFA (polyunsaturated fatty acids) and MUFA (monounsaturated fatty acids) and have low levels of SFA (saturated fatty acids). The predominant fatty acid present in all pecan nuts oils was linoleic acid followed by oleic acid. Myristic acid, palmitic acid, and linolenic acid were also identified in representative quantities. The results from this study suggest that there are statistically significant differences in the chemical composition of the pecan nuts oils extracted from the varieties cultured in Chihuahua, Mexico, and those cultivated in other regions of the world.

  2. Pecan walnut (Carya illinoinensis (Wangenh.) K. Koch) oil quality and phenolic compounds as affected by microwave and conventional roasting.

    Science.gov (United States)

    Juhaimi, Fahad Al; Özcan, Mehmet Musa; Uslu, Nurhan; Doğu, Süleyman

    2017-12-01

    In this study, the effects of conventional and microwave roasting on phenolic compounds, free acidity, peroxide value, fatty acid composition and tocopherol content of pecan walnut kernel and oil was investigated. The oil content of pecan kernels was 73.78% for microwave oven roasted at 720 W and 73.56% for conventional oven roasted at 110 °C. The highest free fatty acid content (0.50%) and the lowest peroxide value (2.48 meq O 2 /kg) were observed during microwave roasting at 720 W. The fatty acid profiles and tocopherol contents of pecan kernel oils did not show significant differences compared to raw samples. Roasting process in microwave oven at 720 W caused the reduction of some phenolic compounds, while the content of gallic acid exhibited a significant increase.

  3. Effects of entomopathogenic fungus species, and impact of fertilizers, on biological control of pecan weevil (Coleoptera: Curculionidae).

    Science.gov (United States)

    Shapiro-Ilan, David I; Gardner, Wayne A; Wells, Lenny; Cottrell, Ted E; Behle, Robert W; Wood, Bruce W

    2013-04-01

    The pecan weevil, Curculio caryae (Horn), is a key pest of pecan, Carya illinoinensis (Wangenh.) K. Koch. Prior research indicated the potential for use of Hypocreales fungi to suppress C. caryae. We compared the efficacy of two fungal spp., Beauveria bassiana (GHA strain) and Metarhizium brunneum (F52), in their ability to cause C. caryae mortality. The fungus, B. bassiana, was applied to trunks of pecan trees (a method previously shown to be effective in C. caryae suppression) and efficacy was compared with M. brunneum applied to the ground or to the trunk with or without SoyScreen Oil as an ultraviolet protecting agent. Results indicated B. bassiana to be superior to M. brunneum regardless of application method; consequently, the potential for applying B. bassiana to control C. caryae was explored further. Specifically, the impact of different fertilizer regimes (as used by pecan growers) on the persistence of B. bassiana (GHA) in soil was determined. B. bassiana was applied to soil in a pecan orchard after one of several fertilizer treatments--i.e., ammonium nitrate, crimson clover, poultry litter, clover plus poultry litter, and a no-fertilizer control. B. bassiana persistence up to 49 d in 2009 and 2010 was assessed by plating soil onto selective media and determining the number of colony forming units, and by baiting soil with a susceptible host, Galleria mellonella (L.). Fertilizer treatments did not impact B. bassiana persistence. We conclude that standard fertilizers for nitrogen management, when applied according to recommended practices, are unlikely to negatively impact survival of B. bassiana in pecan orchards when the fungus is applied for C. caryae suppression during weevil emergence. Additional research on interactions between entomopathogenic fungi and fertilizer amendments (or other tree nutrition or soil management practices) is merited.

  4. The effects of gamma irradiation on the vitamin E content and sensory qualities of pecan nuts (Carya illinoensis)

    Energy Technology Data Exchange (ETDEWEB)

    Taipina, Magda S. [Nuclear and Energy Research Institute, IPEN-CNEN/SP, Av. Prof. L. Prestes 2242, 05508-000 Sao Paulo (Brazil); Lamardo, Leda C.A.; Rodas, Maria A.B. [Instituto Adolfo Lutz, Av. Dr. Arnaldo 355, 01246-902 Sao Paulo, SP (Brazil); Mastro, Nelida L. del [Nuclear and Energy Research Institute, IPEN-CNEN/SP, Av. Prof. L. Prestes 2242, 05508-000 Sao Paulo (Brazil)], E-mail: nlmastro@ipen.br

    2009-07-15

    Pecan nuts (Carya illinoensis) were treated with gamma irradiation and evaluated for changes in vitamin E content and sensory properties. Irradiation at 1 and 3 kGy resulted in no changes in vitamin E content measured as {alpha}-tocopherol equivalents by a colorimetric method. A trained sensory panel found that irradiation at 1 kGy produced no significant changes in appearance, aroma, texture and flavor attributes. The vitamin E content of irradiated pecan nuts remained stable, but from the point of view of sensory quality a dose of merely 1 kGy can be considered as recommendable.

  5. The effects of gamma irradiation on the vitamin E content and sensory qualities of pecan nuts (Carya illinoensis)

    International Nuclear Information System (INIS)

    Taipina, Magda S.; Lamardo, Leda C.A.; Rodas, Maria A.B.; Mastro, Nelida L. del

    2009-01-01

    Pecan nuts (Carya illinoensis) were treated with gamma irradiation and evaluated for changes in vitamin E content and sensory properties. Irradiation at 1 and 3 kGy resulted in no changes in vitamin E content measured as α-tocopherol equivalents by a colorimetric method. A trained sensory panel found that irradiation at 1 kGy produced no significant changes in appearance, aroma, texture and flavor attributes. The vitamin E content of irradiated pecan nuts remained stable, but from the point of view of sensory quality a dose of merely 1 kGy can be considered as recommendable.

  6. The effects of gamma irradiation on the vitamin E content and sensory qualities of pecan nuts ( Carya illinoensis)

    Science.gov (United States)

    Taipina, Magda S.; Lamardo, Leda C. A.; Rodas, Maria A. B.; del Mastro, Nelida L.

    2009-07-01

    Pecan nuts ( Carya illinoensis) were treated with gamma irradiation and evaluated for changes in vitamin E content and sensory properties. Irradiation at 1 and 3 kGy resulted in no changes in vitamin E content measured as α-tocopherol equivalents by a colorimetric method. A trained sensory panel found that irradiation at 1 kGy produced no significant changes in appearance, aroma, texture and flavor attributes. The vitamin E content of irradiated pecan nuts remained stable, but from the point of view of sensory quality a dose of merely 1 kGy can be considered as recommendable.

  7. 7 CFR 51.1441 - Half-kernel.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Half-kernel. 51.1441 Section 51.1441 Agriculture... Standards for Grades of Shelled Pecans Definitions § 51.1441 Half-kernel. Half-kernel means one of the separated halves of an entire pecan kernel with not more than one-eighth of its original volume missing...

  8. Inactivation of Salmonella on pecan nutmeats by hot air treatment and oil roasting.

    Science.gov (United States)

    Beuchat, Larry R; Mann, David A

    2011-09-01

    Studies were done to determine the effectiveness of hot air drying, dry roasting, and oil roasting in killing Salmonella on pecan nutmeats. Pecan halves and pieces were inoculated by immersion in a five-serotype suspension of Salmonella or by surface application of powdered chalk containing the pathogen. Hot air treatment of low-moisture (2.8 to 4.1%) and high-moisture (10.5 to 11.2%) immersion-inoculated nutmeats (initial population, 6.18 to 7.16 log CFU/g) at 120°C for 20 min reduced the number of Salmonella by 1.18 to 1.26 and 1.89 to 2.04 log CFU/g, respectively. However, regardless of the moisture content, hot air treatment of pecan halves containing 0.77 log CFU/g at 120°C for 20 min failed to eliminate Salmonella. Reductions were >7 log CFU/g when dry pieces were dry roasted at 160°C for 15 min. Treatment of halves at 140°C for 20 min, 150°C for 15 min, or 170°C for 10 min reduced Salmonella by 5 log CFU/g. The pathogen was slightly more heat resistant in immersion-inoculated nutmeats than on surface-inoculated nutmeats. Exposure of immersion-inoculated pieces to peanut oil at 127°C for 1.5 min or 132°C for 1.0 min reduced the number of Salmonella by 5 log CFU/g. Treatment of halves at 138°C for 2.0 min reduced Salmonella by 5 log CFU/g; treatment at 132°C for 2.5 to 4.0 min did not always achieve this reduction. Hot air treatment cannot be relied upon to reduce Salmonella by 5 log CFU/g of raw pecan nutmeats without changing sensory qualities. Treatment temperatures and times typically used to oil roast nutmeats appear to be sufficient to reduce Salmonella by 5 log CFU/g.

  9. 7 CFR 51.2547 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... Standards for Grades of Pistachio Nuts in the Shell § 51.2547 Definitions. (a) Well dried means the kernel... to nuts, or any substance other than pistachio shells or kernels. Glass, metal or live insects shall... inch round opening. (5) Undersize means pistachio nuts in the shell which fall through a 30/64 inch...

  10. Growth and mortality of pin oak and pecan reforestation in a constructed wetland: analysis with management implications

    Science.gov (United States)

    D.E. Henderson; P. Botch; J. Cussimanio; D. Ryan; J. Kabrick; D. Dey

    2009-01-01

    Pin oak (Quercus palustris Muenchh.) and pecan (Carya illinoensis (Wangenh.) K. Koch) trees were planted on reforestation plots at Four Rivers Conservation Area in west-central Missouri. The study was conducted to determine survival and growth rates of the two species under different production methods and environmental variables....

  11. Analysis of pecan nut (Carya illinoinensis) unsaponifiable fraction. Effect of ripening stage on phytosterols and phytostanols composition.

    Science.gov (United States)

    Bouali, Intidhar; Trabelsi, Hajer; Herchi, Wahid; Martine, Lucy; Albouchi, Ali; Bouzaien, Ghaith; Sifi, Samira; Boukhchina, Sadok; Berdeaux, Olivier

    2014-12-01

    Changes in 4-desmethylsterol, 4-monomethylsterol, 4,4-dimethylsterol and phytostanol composition were quantitatively and qualitatively investigated during the ripening of three varieties of Tunisian-grown pecan nuts (Mahan, Moore and Burkett). These components have many health benefits, especially in lowering LDL-cholesterol and preventing heart disease. The phytosterol composition of whole pecan kernel was quantified by Gas Chromatography-Flame Ionisation Detection (GC-FID) and identified by Gas Chromatography-Mass Spectrometry (GC-MS). Fifteen phytosterols and one phytostanol were quantified. The greatest amount of phytosterols (2852.5mg/100g of oil) was detected in Mahan variety at 20 weeks after the flowering date (WAFD). Moore had the highest level of phytostanols (7.3mg/100g of oil) at 20 WAFD. Phytosterol and phytostanol contents showed a steep decrease during pecan nut development. Results from the quantitative characterisation of pecan nut oils revealed that β-sitosterol, Δ5-avenasterol, and campesterol were the most abundant phytosterol compounds at all ripening stages. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Sustainable Application of Pecan Nutshell Waste: Greener Synthesis of Pd-based Nanocatalysts for Electro-oxidation of Methanol

    Science.gov (United States)

    Palladium-based electrocatalysts are widely used in alkaline direct alcohol fuel cells. Thesynthesis and characterization of carbon-supported bimetallic nanoparticles (NP) of AuPdand AgPd is described using pecan nutshell extract (Carya illinoinensis) which serves asboth, reducin...

  13. Characterization of pecan nut expeller cake and effect of storage on its microbiological and oxidative quality

    International Nuclear Information System (INIS)

    Marchetti, L.; Romero, L.; Andrés, S.C.; Califano, A.N.

    2017-01-01

    Pecan nut expeller cake (PNEC), a by-product of pecan oil extraction, was characterized and the effect of packaging and storage conditions was investigated. Samples were packaged under vacuum or in normal atmosphere and stored (10 or 20 ºC) for 12 months. Its composition, water and oil absorption, fatty acids profile, lipid oxidation (thiobarbituric acid reactive substances, TBARS), antioxidant activity [Diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl] radical, DPPH● and [(2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)] radical cation, ABTS●+), and microbiological quality were analyzed. PNEC showed high lipid and fiber contents (51.4 and 21.6 g/100g, respectively) with good water and oil absorption capacity. Vacuum storage at 10 ºC preserved antioxidant capacity (TBARS: malondialdehyde= 0.23 mg/kg, IC50 DPPH = 9.0 mg/mL, and IC50 ABTS = 21 mg/mL after one year storage). Extremely low mold and yeast levels were found in PNEC in low permeability vacuum packages, regardless of the storage temperature. Thus, PNEC could retain suitable quality attributes for up to 12 months using the right combination of packaging and temperature. [es

  14. Transcriptomic Analysis Provides Insights into Grafting Union Development in Pecan (Carya illinoinensis).

    Science.gov (United States)

    Mo, Zhenghai; Feng, Gang; Su, Wenchuan; Liu, Zhuangzhuang; Peng, Fangren

    2018-02-05

    Pecan ( Carya illinoinensis ), as a popular nut tree, has been widely planted in China in recent years. Grafting is an important technique for its cultivation. For a successful grafting, graft union development generally involves the formation of callus and vascular bundles at the graft union. To explore the molecular mechanism of graft union development, we applied high throughput RNA sequencing to investigate the transcriptomic profiles of graft union at four timepoints (0 days, 8 days, 15 days, and 30 days) during the pecan grafting process. After de novo assembly, 83,693 unigenes were obtained, and 40,069 of them were annotated. A total of 12,180 differentially expressed genes were identified between by grafting. Genes involved in hormone signaling, cell proliferation, xylem differentiation, cell elongation, secondary cell wall deposition, programmed cell death, and reactive oxygen species (ROS) scavenging showed significant differential expression during the graft union developmental process. In addition, we found that the content of auxin, cytokinin, and gibberellin were accumulated at the graft unions during the grafting process. These results will aid in our understanding of successful grafting in the future.

  15. Characterization of pecan nut expeller cake and effect of storage on its microbiological and oxidative quality

    Directory of Open Access Journals (Sweden)

    L. Marchetti

    2018-01-01

    Full Text Available Pecan nut expeller cake (PNEC, a by-product of pecan oil extraction, was characterized and the effect of packaging and storage conditions was investigated. Samples were packaged under vacuum or in normal atmosphere and stored (10 or 20 ºC for 12 months. Its composition, water and oil absorption, fatty acids profile, lipid oxidation (thiobarbituric acid reactive substances, TBARS, antioxidant activity [Diphenyl-1-(2,4,6-trinitrophenylhydrazyl] radical, DPPH● and [(2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid] radical cation, ABTS●+, and microbiological quality were analyzed. PNEC showed high lipid and fiber contents (51.4 and 21.6 g/100g, respectively with good water and oil absorption capacity. Vacuum storage at 10 ºC preserved antioxidant capacity (TBARS: malondialdehyde= 0.23 mg/kg, IC50 DPPH = 9.0 mg/mL, and IC50 ABTS = 21 mg/mL after one year storage. Extremely low mold and yeast levels were found in PNEC in low permeability vacuum packages, regardless of the storage temperature. Thus, PNEC could retain suitable quality attributes for up to 12 months using the right combination of packaging and temperature.

  16. Morphological and molecular characterization of Cladosporium cladosporioides species complex causing pecan tree leaf spot.

    Science.gov (United States)

    Walker, C; Muniz, M F B; Rolim, J M; Martins, R R O; Rosenthal, V C; Maciel, C G; Mezzomo, R; Reiniger, L R S

    2016-09-16

    The objective of this study was to characterize species of the Cladosporium cladosporioides complex isolated from pecan trees (Carya illinoinensis) with symptoms of leaf spot, based on morphological and molecular approaches. Morphological attributes were assessed using monosporic cultures on potato dextrose agar medium, which were examined for mycelial growth, sporulation, color, and conidia and ramoconidia size. Molecular characterization comprised isolation of DNA and subsequent amplification of the translation elongation factor 1α (TEF-1α) region. Three species of the C. cladosporioides complex were identified: C. cladosporioides, Cladosporium pseudocladosporioides, and Cladosporium subuliforme. Sporulation was the most important characteristic differentiating species of this genus. However, morphological features must be considered together with molecular analysis, as certain characters are indistinguishable between species. TEF-1αcan be effectively used to identify and group isolates belonging to the C. cladosporioides complex. The present study provides an important example of a methodology to ascertain similarity between isolates of this complex causing leaf spot in pecan trees, which should facilitate future pathogenicity studies.

  17. Trap Height Affects Capture of Lady Beetles (Coleoptera: Coccinellidae) in Pecan Orchards.

    Science.gov (United States)

    Cottrell, T E

    2017-04-01

    There is scarce information regarding the vertical stratification of predaceous Coccinellidae in tall trees. Although numerous studies have been done in orchards and forests, very few studies have assessed the occurrence of predaceous Coccinellidae high in tree canopies. The objective of this study was to examine the abundance of Coccinellidae at different heights in mature pecan, Carya illinoinensis (Wangenh.) K. Koch, orchards with tall trees. From spring through late fall during 2013 and 2014, yellow pyramidal Tedders traps were suspended in the pecan canopy at 6.1 and 12.2 m, in addition to being placed on the ground (0 m). The exotic species Harmonia axyridis and Coccinella septempunctata accounted for a high percentage of trap capture during this study. Except for Olla v-nigrum, low numbers of native species (Hippodamia convergens, Coleomegilla maculata, Cycloneda munda, Scymnus spp., and Hyperaspis spp.) were captured. However, significantly more were captured in ground traps rather than in canopy traps with the exception of O. v-nigrum. Similar to most native species, significantly more C. septempunctata were captured in ground traps than canopy traps. This contrasts sharply with H. axyridis captured similarly at all trap heights. The ability to exploit resources across vertical strata, unlike many intraguild predators, may be an underestimated factor helping to explain the invasiveness of H. axyridis. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by a US Government employee and is in the public domain in the US.

  18. Pecan (Carya illinoinensis/Wangenh./K. Koch: A new species of the Allochthonous dendroflora in Serbia

    Directory of Open Access Journals (Sweden)

    Bobinac Martin

    2014-01-01

    Full Text Available This paper presents the alien species Carya illinoinensis (Wangenh. K. Koch, carya-pecan, (Juglandaceae A. Richard ex Kunth that has not been mentioned so far in the dendroflora of Serbia. One tree was recorded within the first Serbian sugar factory in Čukarica that is now a protected cultural property in the City of Belgrade. The tree is about 35 years old and about 20 m high. The length of the trunk without branches is 6.0 m and the diameter at breast height is 57 cm. Carya-pecan is a native species of the southeastern part of North America, and is grown in Europe for edible fruits and quality wood. The recorded tree in Belgrade is fruitful and characterized by good vitality and rapid growth. Due to its special characteristics, it can have multiple practical application in the territory of Serbia for decoration in urban areas, for forest plantations and in orchards. [Projekat Ministarstva nauke Republike Srbije, br. 31041: Šumski zasadi u funkciji povećanja pošumljenosti Srbije

  19. Transcriptomic Analysis Provides Insights into Grafting Union Development in Pecan (Carya illinoinensis

    Directory of Open Access Journals (Sweden)

    Zhenghai Mo

    2018-02-01

    Full Text Available Pecan (Carya illinoinensis, as a popular nut tree, has been widely planted in China in recent years. Grafting is an important technique for its cultivation. For a successful grafting, graft union development generally involves the formation of callus and vascular bundles at the graft union. To explore the molecular mechanism of graft union development, we applied high throughput RNA sequencing to investigate the transcriptomic profiles of graft union at four timepoints (0 days, 8 days, 15 days, and 30 days during the pecan grafting process. After de novo assembly, 83,693 unigenes were obtained, and 40,069 of them were annotated. A total of 12,180 differentially expressed genes were identified between by grafting. Genes involved in hormone signaling, cell proliferation, xylem differentiation, cell elongation, secondary cell wall deposition, programmed cell death, and reactive oxygen species (ROS scavenging showed significant differential expression during the graft union developmental process. In addition, we found that the content of auxin, cytokinin, and gibberellin were accumulated at the graft unions during the grafting process. These results will aid in our understanding of successful grafting in the future.

  20. RNA-Seq Analysis of Developing Pecan (Carya illinoinensis) Embryos Reveals Parallel Expression Patterns among Allergen and Lipid Metabolism Genes.

    Science.gov (United States)

    Mattison, Christopher P; Rai, Ruhi; Settlage, Robert E; Hinchliffe, Doug J; Madison, Crista; Bland, John M; Brashear, Suzanne; Graham, Charles J; Tarver, Matthew R; Florane, Christopher; Bechtel, Peter J

    2017-02-22

    The pecan nut is a nutrient-rich part of a healthy diet full of beneficial fatty acids and antioxidants, but can also cause allergic reactions in people suffering from food allergy to the nuts. The transcriptome of a developing pecan nut was characterized to identify the gene expression occurring during the process of nut development and to highlight those genes involved in fatty acid metabolism and those that commonly act as food allergens. Pecan samples were collected at several time points during the embryo development process including the water, gel, dough, and mature nut stages. Library preparation and sequencing were performed using Illumina-based mRNA HiSeq with RNA from four time points during the growing season during August and September 2012. Sequence analysis with Trinotate software following the Trinity protocol identified 133,000 unigenes with 52,267 named transcripts and 45,882 annotated genes. A total of 27,312 genes were defined by GO annotation. Gene expression clustering analysis identified 12 different gene expression profiles, each containing a number of genes. Three pecan seed storage proteins that commonly act as allergens, Car i 1, Car i 2, and Car i 4, were significantly up-regulated during the time course. Up-regulated fatty acid metabolism genes that were identified included acyl-[ACP] desaturase and omega-6 desaturase genes involved in oleic and linoleic acid metabolism. Notably, a few of the up-regulated acyl-[ACP] desaturase and omega-6 desaturase genes that were identified have expression patterns similar to the allergen genes based upon gene expression clustering and qPCR analysis. These findings suggest the possibility of coordinated accumulation of lipids and allergens during pecan nut embryogenesis.

  1. Electromagnetic properties of off-shell particles and gauge invariance

    NARCIS (Netherlands)

    Nagorny, S. I.; Dieperink, A. E. L.

    1998-01-01

    Abstract: Electromagnetic properties of off-shell particles are discussed on the basis of a purely electromagnetic reaction: virtual Compton scattering off a proton. It is shown that the definition of off-shell electromagnetic form factors is not gauge invariant and that these cannot be investigated

  2. PECAN: library-free peptide detection for data-independent acquisition tandem mass spectrometry data

    Energy Technology Data Exchange (ETDEWEB)

    Ting, Ying S.; Egertson, Jarrett D.; Bollinger, James G.; Searle, Brian C.; Payne, Samuel H.; Noble, William Stafford; MacCoss, Michael J.

    2017-08-07

    Data-independent acquisition (DIA) is an emerging mass spectrometry (MS)-based technique for unbiased and reproducible measurement of protein mixtures. DIA tandem mass spectrometry spectra are often highly multiplexed, containing product ions from multiple cofragmenting precursors. Detecting peptides directly from DIA data is therefore challenging; most DIA data analyses require spectral libraries. Here we present PECECAN (http://pecan.maccosslab.org), a library-free, peptide-centric tool that robustly and accurately detects peptides directly from DIA data. PECECAN reports evidence of detection based on product ion scoring, which enables detection of low-abundance analytes with poor precursor ion signal. We demonstrate the chromatographic peak picking accuracy and peptide detection capability of PECECAN, and we further validate its detection with data-dependent acquisition and targeted analyses. Lastly, we used PECECAN to build a plasma proteome library from DIA data and to query known sequence variants.

  3. Wideband propagation measurements at 30.3 GHz through a pecan orchard in Texas

    Science.gov (United States)

    Papazian, Peter B.; Jones, David L.; Espeland, Richard H.

    1992-09-01

    Wideband propagation measurements were made in a pecan orchard in Texas during April and August of 1990 to examine the propagation characteristics of millimeter-wave signals through vegetation. Measurements were made on tree obstructed paths with and without leaves. The study presents narrowband attenuation data at 9.6 and 28.8 GHz as well as wideband impulse response measurements at 30.3 GHz. The wideband probe (Violette et al., 1983), provides amplitude and delay of reflected and scattered signals and bit-error rate. This is accomplished using a 500 MBit/sec pseudo-random code to BPSK modulate a 28.8 GHz carrier. The channel impulse response is then extracted by cross correlating the received pseudo-random sequence with a locally generated replica.

  4. Fertilización de base en un cultivo inicial de pecan con dos marcos de plantación de alta densidad Effect of different fertilization strategies on pecan growth parameters under two high density plantation frames

    Directory of Open Access Journals (Sweden)

    Lidia Giuffré

    2011-07-01

    Full Text Available El pecán, Carya illinoensis Koch, es una especie cuyo fruto es reconocido como un alimento altamente saludable. Su cultivo se encuentra en expansión en la Argentina pero existen muy pocas investigaciones sobre fertilización y sistemas de plantación. Los objetivos del trabajo fueron caracterizar algunas propiedades físico-químicas y químicas de un suelo en el que se inicia un cultivo de pecán, y comparar tratamientos de fertilización de base (FB en dos marcos de plantación de alta densidad (MP. Se realizó una plantación de pecán en Villanueva (provincia de Buenos Aires, sobre un suelo Hapludol taptoárgico, con dos marcos de plantación: 10 x 10 m (marco real: MR y 8 x 8 m (tresbolillo: TR. El diseño del experimento fue en parcelas divididas con cuatro repeticiones. La parcela principal fueron los dos marcos de plantación, y las subparcelas fueron los distintos tratamientos de fertilización base: Compost (C, Fósforo (P, Nitrógeno (N y Control sin fertilización base (T. Las determinaciones para evaluar el crecimiento de las plantas de pecán fueron: la altura de las plantas y el diámetro del tronco. Con respecto a la fertilidad del suelo, la fertilización fosforada y el agregado de compost permitieron aumentar significativamente los niveles de P-Bray. El tratamiento con fertilización orgánica: compost, presentó un incremento significativo en altura de los pecanes en el marco de plantación 8 x 8 m, que no se manifestó en ningún caso en los diámetros del tronco, con una interacción MP x FB significativa (P=0,01 para la variación de altura al primer año. La variación del volumen del árbol durante el año de experimentación no presentó efectos significativos según el marco de plantación ni la fertilización base aplicada.The fruit of the pecan tree, Carya illinoensis Koch, is considered a very healthy food. In Argentina, pecan cultivation has been expanding rapidly but very little research has been conducted on

  5. Salinity management using an anionic polymer in a pecan field with calcareous-sodic soil.

    Science.gov (United States)

    Ganjegunte, Girisha K; Sheng, Zhuping; Braun, Robert J

    2011-01-01

    Soil salinity and sodicity have long been recognized as the major concerns for irrigated agriculture in the Trans-Pecos Basin, where fields are being flood irrigated with Rio Grande River water that has elevated salinity. Reclamation of these salt-affected lands is difficult due to fine-texture, high shrink-swell soils with low permeability. Conventional practice of subsoiling to improve soil permeability is expensive and has had limited success on the irrigated soils that have appreciable amounts of readily weatherable Ca minerals. If these native Ca sources can be effectively used to counter sodicity, it can improve soil permeability and reduce amelioration costs. This study evaluated the effects of 3 yr of polyacrylamide (PAM) application at 10 mg L concentration during the first irrigation of the season to evaluate soil permeability, in situ Ca mineral dissolution, and leaching of salts from the effective root zone in a pecan field of El Paso County, TX. Results indicated that PAM application improved water movement throughout the effective root zone that resulted in Na leaching. Polymer application significantly decreased CaCO (estimated based on inorganic C analysis) concentrations in the top 45 cm compared with baseline levels, indicating solubilization and redistribution of calcite. The PAM application also reduced soil electrical conductivity (EC) in the top 60 cm (4.64-2.76 dS m) and sodium adsorption ratio (SAR) from 13.1 to 5.7 mmol L in the top 75-cm depths. As evidence of improved soil conditions, pecan nut yields increased by 34% in PAM-treated fields over the control. Results suggested that PAM application helped in effective use of native Ca sources present in soils of the study site and reduced Na by improving soil permeability. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  6. ARM Support for the Plains Elevated Convection at Night (AS-PECAN) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Turner, D. D. [National Oceanic and Atmospheric Administration (NOAA), Silver Spring, MD (United States); Geerts, B. [Univ. of Wyoming, Laramie, WY (United States)

    2016-04-01

    The Plains Elevated Convection at Night (PECAN) field campaign was a large multi-agency/multi-institutional experiment that targeted nighttime convection events in the central plains of the United States in order to better understand a range of processes that lead to the initiation and upscale growth of deep convection. Both weather and climate models struggle to properly represent the timing and intensity of precipitation in the central United States in their simulations. These models must be able to represent the interactions between the nocturnal stable boundary layer (SBL), the nocturnal low-level jet (LLJ), and a reservoir of convectively available potential energy (CAPE) that frequently exists above the SBL. Furthermore, a large fraction of the nocturnal precipitation is due to the organization of mesoscale convective systems (MCSs). In particular, there were four research foci for the PECAN campaign: •The initiation of elevated nocturnal convection focus seeks to elucidate the mesoscaleenvironmental characteristics and processes that lead to convection initiation (CI) and provide baseline data on the early evolution of mesoscale convective clusters. •The dynamics and internal structure and microphysics of nocturnal MCSs focus will investigatethe transition from surface-based to elevated storm structure, the interaction of cold pools generated by MCSs with the nocturnal stable boundary layer, and how the organization and evolution of elevated convection is influenced by the SBL and the vertical profile of wind and stability above the LLJ. •The bores and wave-like disturbances focus seeks to advance knowledge of the initiation of boredisturbances by convection, how the vertical profile of stability and winds modulate bore structure, the role of these disturbances in the initiation, maintenance, and organization of deep convection, and their impact on the LLJ and SBL. •The LLJ focus seeks to understand the processes that influence the spatial and

  7. Nickel Deficiency Disrupts Metabolism of Ureides, Amino Acids, and Organic Acids of Young Pecan Foliage[OA

    Science.gov (United States)

    Bai, Cheng; Reilly, Charles C.; Wood, Bruce W.

    2006-01-01

    The existence of nickel (Ni) deficiency is becoming increasingly apparent in crops, especially for ureide-transporting woody perennials, but its physiological role is poorly understood. We evaluated the concentrations of ureides, amino acids, and organic acids in photosynthetic foliar tissue from Ni-sufficient (Ni-S) versus Ni-deficient (Ni-D) pecan (Carya illinoinensis [Wangenh.] K. Koch). Foliage of Ni-D pecan seedlings exhibited metabolic disruption of nitrogen metabolism via ureide catabolism, amino acid metabolism, and ornithine cycle intermediates. Disruption of ureide catabolism in Ni-D foliage resulted in accumulation of xanthine, allantoic acid, ureidoglycolate, and citrulline, but total ureides, urea concentration, and urease activity were reduced. Disruption of amino acid metabolism in Ni-D foliage resulted in accumulation of glycine, valine, isoleucine, tyrosine, tryptophan, arginine, and total free amino acids, and lower concentrations of histidine and glutamic acid. Ni deficiency also disrupted the citric acid cycle, the second stage of respiration, where Ni-D foliage contained very low levels of citrate compared to Ni-S foliage. Disruption of carbon metabolism was also via accumulation of lactic and oxalic acids. The results indicate that mouse-ear, a key morphological symptom, is likely linked to the toxic accumulation of oxalic and lactic acids in the rapidly growing tips and margins of leaflets. Our results support the role of Ni as an essential plant nutrient element. The magnitude of metabolic disruption exhibited in Ni-D pecan is evidence of the existence of unidentified physiological roles for Ni in pecan. PMID:16415214

  8. Influence of yield on in vitro accumulation of aflatoxins in pecan (Carya illinoensis (Wang.) K. Koch) nutmeats.

    Science.gov (United States)

    McMeans, J L

    1983-02-01

    Pecans were harvested from trees (Carya illinoensis (Wang.) K. Koch) in November of 1977 through 1979. Kernel meals from high-, medium-, and low-yielding trees were inoculated with a spore suspension of Aspergillus parasiticus and incubated for 7 days at 25 degrees C. Significant differences in aflatoxin accumulation were found among the three substrates, with a direct correlation between high aflatoxin concentration and tree yield.

  9. Influence of yield on in vitro accumulation of aflatoxins in pecan (Carya illinoensis (Wang.) K. Koch) nutmeats.

    OpenAIRE

    McMeans, J L

    1983-01-01

    Pecans were harvested from trees (Carya illinoensis (Wang.) K. Koch) in November of 1977 through 1979. Kernel meals from high-, medium-, and low-yielding trees were inoculated with a spore suspension of Aspergillus parasiticus and incubated for 7 days at 25 degrees C. Significant differences in aflatoxin accumulation were found among the three substrates, with a direct correlation between high aflatoxin concentration and tree yield.

  10. Effect of pecan phenolics on the release of nitric oxide from murine RAW 264.7 macrophage cells.

    Science.gov (United States)

    Robbins, Katherine S; Greenspan, Phillip; Pegg, Ronald B

    2016-12-01

    Inflammation is linked to numerous chronic disease states. Phenolic compounds have attracted attention because a number of these compounds possess anti-inflammatory properties. A phenolic crude extract was prepared from pecans and separated by Sephadex LH-20 column chromatography into low- and high-molecular-weight (LMW/HMW) fractions. Anti-inflammatory properties of these fractions were assessed in LPS-stimulated RAW 264.7 murine macrophage cells. NO and reactive oxygen species (ROS) production was monitored after 3 different experimental protocols: (1) pre-treatment with Escherichia coli O111:B4 lipopolysaccharide (LPS); (2) pre-treatment with a pecan crude extract and its fractions; and (3) co-incubation of LPS with a pecan crude extract and its fractions. The LMW fraction displayed a dose-dependent decrease in NO production and a significant decrease from the LPS control in ROS production when cells were either co-incubated with or pre-treated with LPS. The phenolics were characterized by HPLC to help identify those responsible for the observed effect. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. LASE measurements of water vapor and aerosol profiles during the Plains Elevated Convection at Night (PECAN) field experiment

    Science.gov (United States)

    Nehrir, A. R.; Ferrare, R. A.; Kooi, S. A.; Butler, C. F.; Notari, A.; Hair, J. W.; Collins, J. E., Jr.; Ismail, S.

    2015-12-01

    The Lidar Atmospheric Sensing Experiment (LASE) system was deployed on the NASA DC-8 aircraft during the Plains Elevated Convection At Night (PECAN) field experiment, which was conducted during June-July 2015 over the central and southern plains. LASE is an active remote sensor that employs the differential absorption lidar (DIAL) technique to measure range resolved profiles of water vapor and aerosols above and below the aircraft. The DC-8 conducted nine local science flights from June 30- July 14 where LASE sampled water vapor and aerosol fields in support of the PECAN primary science objectives relating to better understanding nocturnal Mesoscale Convective Systems (MCSs), Convective Initiation (CI), the Low Level Jet (LLJ), bores, and to compare different airborne and ground based measurements. LASE observed large spatial and temporal variability in water vapor and aerosol distributions in advance of nocturnal MCSs, across bores resulting from MCS outflow boundaries, and across the LLJ associated with the development of MCSs and CI. An overview of the LASE data collected during the PECAN field experiment will be presented where emphasis will be placed on variability of water vapor profiles in the vicinity of severe storms and intense convection in the central and southern plains. Preliminary comparisons show good agreement between coincident LASE and radiosonde water vapor profiles. In addition, an advanced water vapor DIAL system being developed at NASA Langley will be discussed.

  12. Differences in bacterial diversity of host-associated populations of Phylloxera notabilis Pergande (Hemiptera: Phylloxeridae) in pecan and water hickory.

    Science.gov (United States)

    Medina, R F; Nachappa, P; Tamborindeguy, C

    2011-04-01

    Host-associated differentiation (HAD) is the presence of genetically divergent, host-associated populations. It has been suggested that microbial symbionts of insect herbivores may play a role in HAD by allowing their insect hosts to use different plant species. The objective of this study was to document if host-associated populations of Phylloxera notabilis Pergande (Hemiptera: Phylloxeridae) in pecan and water hickory corresponded with differences in the composition of their associated bacteria. To test this hypothesis, we characterized the symbionts present in P. notabilis associated with these two tree species through metagenomic analyses using 454 sequencing. Differences in bacterial diversity were found between P. notabilis populations associated with pecan and water hickory. The bacteria, Pantoea agglomerans and Serratia marcescens, were absent in the P. notabilis water hickory population, whereas both species accounted for more than 69.72% of bacterial abundance in the pecan population. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

  13. Coal option. [Shell Co

    Energy Technology Data Exchange (ETDEWEB)

    1978-01-01

    This paper notes the necessity of developing an international coal trade on a very large scale. The role of Shell in the coal industry is examined; the regions in which Shell companies are most active are Australia, Southern Africa, Indonesia; Europe and North America. Research is being carried out on marketing and transportation, especially via slurry pipelines; coal-oil emulsions; briquets; fluidized-bed combustion; recovery of coal from potential waste material; upgrading of low-rank coals; unconventional forms of mining; coal conversion (the Shell/Koppers high-pressure coal gasification process). Techniques for cleaning flue gas (the Shell Flue Gas Desulfurization process) are being examined.

  14. Shell-like structures

    CERN Document Server

    Altenbach, Holm

    2011-01-01

    In this volume, scientists and researchers from industry discuss the new trends in simulation and computing shell-like structures. The focus is put on the following problems: new theories (based on two-dimensional field equations but describing non-classical effects), new constitutive equations (for materials like sandwiches, foams, etc. and which can be combined with the two-dimensional shell equations), complex structures (folded, branching and/or self intersecting shell structures, etc.) and shell-like structures on different scales (for example: nano-tubes) or very thin structures (similar

  15. Randomized branch sampling to estimatefruit production in Pecan trees cv. ‘Barton’

    Directory of Open Access Journals (Sweden)

    Filemom Manoel Mokochinski

    Full Text Available ABSTRACT: Sampling techniques to quantify the production of fruits are still very scarce and create a gap in crop development research. This study was conducted in a rural property in the county of Cachoeira do Sul - RS to estimate the efficiency of randomized branch sampling (RBS in quantifying the production of pecan fruit at three different ages (5,7 and 10 years. Two selection techniques were tested: the probability proportional to the diameter (PPD and the uniform probability (UP techniques, which were performed on nine trees, three from each age and randomly chosen. The RBS underestimated fruit production for all ages, and its main drawback was the high sampling error (125.17% - PPD and 111.04% - UP. The UP was regarded as more efficient than the PPD, though both techniques estimated similar production and similar experimental errors. In conclusion, we reported that branch sampling was inaccurate for this case study, requiring new studies to produce estimates with smaller sampling error.

  16. Microbial Lipid Production from Enzymatic Hydrolysate of Pecan Nutshell Pretreated by Combined Pretreatment.

    Science.gov (United States)

    Qin, Lizhen; Qian, Hanyu; He, Yucai

    2017-12-01

    Biodiesel is a fuel composed of monoalkyl esters of long-chain fatty acids derived from renewable biomass sources. In this study, biomass waste pecan nutshell (PS) was attempted to be converted into microbial oil. For effective utilization of PS, sequential pretreatment with ethylene glycol-H 2 SO 4 -water (78:2:20, wt:wt:wt) at 130 °C for 30 min and aqueous ammonia (25 wt%) at 50 °C for 24 h was used to enhance its enzymatic saccharification. Significant linear correlation was obtained about delignification-saccharification (R 2  = 0.9507). SEM and FTIR results indicated that combination pretreatment could effectively remove lignin and xylan in PS for promoting its enzymatic saccharification. After 72 h, the reducing sugars from the hydrolysis of 50 g/L pretreated PS by combination pretreatment could be obtained at 73.6% yield. Using the recovered PS hydrolysates containing 20 g/L glucose as carbon source, microbial lipids produced from the PS hydrolysates by Rhodococcus opacus ACCC41043. Four fatty acids including palmitic acid (C16:0; 23.1%), palmitoleic acid (C16:1; 22.4%), stearic acid (C18:0; 15.3%), and oleic acid (C18:1; 23.9%) were distributed in total fatty acids. In conclusion, this strategy has potential application in the future.

  17. Identification and characterization of pathogenic Pestalotiopsis species to pecan tree in Brazil

    Directory of Open Access Journals (Sweden)

    Marília Lazarotto

    2014-06-01

    Full Text Available The objective of this work was to characterize and cluster isolates of Pestalotiopsis species and to identify those that are pathogenic to pecan, based on morphological and molecular characters. Pestalotiopsis spp. isolates were identified by sequencing the internal transcribed spacer (ITS and β?tubulin regions. Identification methods were compared to indicate the key morphological characters for species characterization. Thirteen isolates were used for the pathogenicity tests. Morphological characterization was performed using the following variables: mycelial growth rate, sporulation, colony pigmentation, and conidial length and width. Ten pathogenic isolates were identified, three as -tubulin regions. Identification methods were compared to indicate the key morphological characters for species characterization. Thirteen isolates were used for the pathogenicity tests. Morphological characterization was performed using the following variables: mycelial growth rate, sporulation, colony pigmentation, and conidial length and width. Ten pathogenic isolates were identified, three as Pestalotiopsis clavispora and three as P. cocculi. The other isolates remained as an undefined species. The morphological characters were efficient for an initial separation of the isolates, which were grouped according to differences at species level, mainly colony diameter, which was identified as an important morphological describer. Beta-tubulin gene sequencing was less informative than the ITS region sequencing for species identification.

  18. Comparative study of volatile oil content and antimicrobial activity of pecan cultivars growing in Egypt.

    Science.gov (United States)

    El Hawary, Seham S; Zaghloul, Soumaya S; El Halawany, Ali M; El Bishbishy, Mahitab H

    2013-11-01

    The volatile oils obtained from the leaves of four pecan cultivars growing in Egypt were evaluated for their chemical composition and antimicrobial activity. The selected cultivars (cv.) were Carya illinoinensis (Wangneh.) K. Koch. cv. Wichita, C. illinoinensis cv. Western Schley, C. illinoinensis cv. Cherokee, and C. illinoinensis cv. Sioux. The gas chromatography-mass spectrometry analyses revealed that the volatile oils from samples of the different cultivars differ in composition and percentage of their components. β-Curcumene was found as the major constituent of the cv. Wichita oil, whereas germacrene D was the major component of cv. Sioux, cv. Cherokee, and cv. Western Schley. The antimicrobial activity was assayed using the Kirby-Bauer Method by measuring the zone of inhibition of growth. All volatile oils displayed an antimicrobial activity against the tested bacterial strains. On the other hand, only the volatile oil of cv. Wichita showed an antifungal effect on Aspergillus flavus. This work has identified candidates of volatile oils for future in vivo studies to develop antibiotic substitutes for the diminution of human and animal pathogenic bacteria. Nevertheless, the variations of the volatile oil components and antimicrobial potencies of the different studied cultivars, necessitate identifying the cultivars used in future studies.

  19. Effect of Entomopathogenic Nematodes on Mesocriconema xenoplax Populations in Peach and Pecan

    Science.gov (United States)

    Nyczepir, A. P.; Shapiro-Ilan, D. I.; Lewis, E. E.; Handoo, Z. A.

    2004-01-01

    The effect of Steinernema riobrave and Heterorhabditis bacteriophora on population density of Mesocriconema xenoplax in peach was studied in the greenhouse. Twenty-one days after adding 112 M. xenoplax adults and juveniles/1,500 cm³ soil to the soil surface of each pot, 50 infective juveniles/cm² soil surface of either S. riobrave or H. bacteriophora were applied. Another entomopathogenic nematode application of the same density was administered 3 months later. The experiment was repeated once. Mesocriconema xenoplax populations were not suppressed (P ≤ 0.05) in the presence of either S. riobrave or H. bacteriophora 180 days following ring nematode inoculation. On pecan, 200 S. riobrave infective-stage juveniles/cm² were applied to the soil surface of 2-year-old established M. xenoplax populations in field microplots. Additional applications of S. riobrave were administered 2 and 4 months later. This study was terminated 150 days following the initial application of S. riobrave. Populations of M. xenoplax were not suppressed in the presence of S. riobrave. PMID:19262805

  20. Effect of Entomopathogenic Nematodes on Mesocriconema xenoplax Populations in Peach and Pecan.

    Science.gov (United States)

    Nyczepir, A P; Shapiro-Ilan, D I; Lewis, E E; Handoo, Z A

    2004-06-01

    The effect of Steinernema riobrave and Heterorhabditis bacteriophora on population density of Mesocriconema xenoplax in peach was studied in the greenhouse. Twenty-one days after adding 112 M. xenoplax adults and juveniles/1,500 cm(3) soil to the soil surface of each pot, 50 infective juveniles/cm(2) soil surface of either S. riobrave or H. bacteriophora were applied. Another entomopathogenic nematode application of the same density was administered 3 months later. The experiment was repeated once. Mesocriconema xenoplax populations were not suppressed (P pecan, 200 S. riobrave infective-stage juveniles/cm(2) were applied to the soil surface of 2-year-old established M. xenoplax populations in field microplots. Additional applications of S. riobrave were administered 2 and 4 months later. This study was terminated 150 days following the initial application of S. riobrave. Populations of M. xenoplax were not suppressed in the presence of S. riobrave.

  1. 7 CFR 810.401 - Definition of corn.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Definition of corn. 810.401 Section 810.401... GRAIN United States Standards for Corn Terms Defined § 810.401 Definition of corn. Grain that consists of 50 percent or more of whole kernels of shelled dent corn and/or shelled flint corn (Zea mays L...

  2. 7 CFR 51.2560 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... Standards for Grades of Shelled Pistachio Nuts § 51.2560 Definitions. (a) Well dried means the kernel is... than pistachio kernels. No allowable tolerances for metal or glass. (d) Whole kernel means 3/4 of a...

  3. Shell coal gasification process

    Energy Technology Data Exchange (ETDEWEB)

    Hennekes, B. [Shell Global Solutions (US) Inc. (United States). Technology Marketing

    2002-07-01

    The presentation, on which 17 slides/overheads are included in the papers, explained the principles of the Shell coal gasification process and the methods incorporated for control of sulfur dioxide, nitrogen oxides, particulates and mercury. The economics of the process were discussed. The differences between gasification and burning, and the differences between the Shell process and other processes were discussed.

  4. Wrinkling of Pressurized Elastic Shells

    KAUST Repository

    Vella, Dominic; Ajdari, Amin; Vaziri, Ashkan; Boudaoud, Arezki

    2011-01-01

    We study the formation of localized structures formed by the point loading of an internally pressurized elastic shell. While unpressurized shells (such as a ping-pong ball) buckle into polygonal structures, we show that pressurized shells

  5. Inner-shell couplings in transiently formed superheavy quasimolecules

    Energy Technology Data Exchange (ETDEWEB)

    Verma, P [Kalindi College, University of Delhi, New Delhi 110008 (India); Mokler, P H [Max-Planck-Institut fuer Kernphysik, 69117 Heidelberg (Germany); Braeuning-Demian, A; Kozhuharov, C; Braeuning, H; Bosch, F; Hagmann, S; Liesen, D [GSI Helmholzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Anton, J; Fricke, B [Universitaet Kassel, 34109 Kassel (Germany); Stachura, Z [Institute for Nuclear Physics, Cracow PL 31342 (Poland); Wahab, M A, E-mail: p.verma.du@gmail.com [Jamia Millia Islamia, Jamia Nagar, New Delhi 110025 (India)

    2011-06-15

    The inner-shell couplings for U{sup q+}-ions (73{<=}q{<=}91) moving moderately slow at {approx}69 MeV u{sup -1} and bombarding thin Au targets have been investigated. Having established the definite survival probability of incoming projectile K vacancies in these targets in an earlier publication, the transfer of these vacancies to the target K-shell due to inner-shell couplings has been studied. As the system is in the quasiadiabatic collision regime for the K-shell of collision partners, advanced SCF-DFS (self-consistent field-Dirac-Fock-Slater) multielectron level diagrams have been used for interpretation. Using a simple model, the L-K shell coupling interaction distance has been estimated and compared with level diagram calculations.

  6. Evidence for Sexual Reproduction: Identification, Frequency, and Spatial Distribution of Venturia effusa (Pecan Scab) Mating Type Idiomorphs.

    Science.gov (United States)

    Young, Carolyn A; Bock, Clive H; Charlton, Nikki D; Mattupalli, Chakradhar; Krom, Nick; Bowen, Joanna K; Templeton, Matthew; Plummer, Kim M; Wood, Bruce W

    2018-05-10

    Venturia effusa (syn. Fusicladium effusum), causal agent of pecan scab, is the most prevalent pathogen of pecan (Carya illinoinensis), causing severe yield losses in the southeastern United States. V. effusa is currently known only by its asexual (conidial) stage. However, the degree and distribution of genetic diversity observed within and among populations of V. effusa are typical of a sexually reproducing fungal pathogen, and comparable with other dothideomycetes with a known sexual stage, including the closely related apple scab pathogen, V. inaequalis. Using the mating type (MAT) idiomorphs from V. inaequalis, we identified a single MAT gene, MAT1-1-1, in a draft genome of V. effusa. The MAT1-1-1 locus is flanked by two conserved genes encoding a DNA lyase (APN2) and a hypothetical protein. The MAT locus spanning the flanking genes was amplified and sequenced from a subset of 14 isolates, of which 7 contained MAT1-1-1 and the remaining samples contained MAT1-2-1. A multiplex polymerase chain reaction screen was developed to amplify MAT1-1-1, MAT1-2-1, and a conserved reference gene encoding β-tubulin, and used to screen 784 monoconidial isolates of V. effusa collected from 11 populations of pecan across the southeastern United States. A hierarchical sampling protocol representing region, orchard, and tree allowed for analysis of MAT structure at different spatial scales. Analysis of this collection revealed the frequency of the MAT idiomorphs is in a 1:1 equilibrium of MAT1-1:MAT1-2. The apparent equilibrium of the MAT idiomorphs provides impetus for a renewed effort to search for the sexual stage of V. effusa. [Formula: see text] Copyright © 2018 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

  7. Molluscan shell colour.

    Science.gov (United States)

    Williams, Suzanne T

    2017-05-01

    The phylum Mollusca is highly speciose, and is the largest phylum in the marine realm. The great majority of molluscs are shelled, including nearly all bivalves, most gastropods and some cephalopods. The fabulous and diverse colours and patterns of molluscan shells are widely recognised and have been appreciated for hundreds of years by collectors and scientists alike. They serve taxonomists as characters that can be used to recognise and distinguish species, however their function for the animal is sometimes less clear and has been the focus of many ecological and evolutionary studies. Despite these studies, almost nothing is known about the evolution of colour in molluscan shells. This review summarises for the first time major findings of disparate studies relevant to the evolution of shell colour in Mollusca and discusses the importance of colour, including the effects of visual and non-visual selection, diet and abiotic factors. I also summarise the evidence for the heritability of shell colour in some taxa and recent efforts to understand the molecular mechanisms underpinning synthesis of shell colours. I describe some of the main shell pigments found in Mollusca (carotenoids, melanin and tetrapyrroles, including porphyrins and bile pigments), and their durability in the fossil record. Finally I suggest that pigments appear to be distributed in a phylogenetically relevant manner and that the synthesis of colour is likely to be energetically costly. © 2016 Cambridge Philosophical Society.

  8. Nuclear shell theory

    CERN Document Server

    de-Shalit, Amos; Massey, H S W

    1963-01-01

    Nuclear Shell Theory is a comprehensive textbook dealing with modern methods of the nuclear shell model. This book deals with the mathematical theory of a system of Fermions in a central field. It is divided into three parts. Part I discusses the single particle shell model. The second part focuses on the tensor algebra, two-particle systems. The last part covers three or more particle systems. Chapters on wave functions in a central field, tensor fields, and the m-Scheme are also presented. Physicists, graduate students, and teachers of nuclear physics will find the book invaluable.

  9. 78 FR 13454 - Common Crop Insurance Regulations; Pecan Revenue Crop Insurance Provisions

    Science.gov (United States)

    2013-02-28

    ... meaning of the definition to allow a choice of either four or six years of sales records to be used to... adding ``2014'' in its place; 0 b. In section 1 by: 0 i. Revising the definitions of ``approved average... Provisions for the 2013 crop year by changing the definition of two-year coverage module to one crop year...

  10. Fine scale population genetic structure and within tree distribution of mating types of Venturia effusa, cause of pecan scab in the USA

    Science.gov (United States)

    Scab (caused by Venturia effusa) is the major disease of pecan in the southeastern USA. There is no information available on the fine scale population genetic diversity. Four cv. Wichita trees (populations) were sampled hierarchically. Within each tree canopy, 4 approximately evenly spaced terminals...

  11. Structural Characteristics of Nocturnal Mesoscale Convective Systems in the U.S. Great Plains as Observed During the PECAN Field Campaign

    Science.gov (United States)

    Bodine, D. J.; Dougherty, E.; Rasmussen, K. L.; Torres, A. D.

    2015-12-01

    During the summer in the U.S. Great Plains, some of the heaviest precipitation falls from large thunderstorm complexes known as Mesoscale Convective Systems (MCSs). These frequently occurring MCSs are often nocturnal in nature, so the dynamics associated with these systems are more elusive than those in the daytime. The Plains Elevated Convection at Night (PECAN) field campaign was launched over a 7-week period as an endeavor to better understand nocturnal MCSs occurring in the Great Plains. PECAN featured a dense array of ground-based and airborne instruments to observe nocturnal MCS, including dual-polarization radars at multiple frequencies, mobile mesonets, and sounding units. Our role in PECAN involved deploying Ott Parsivel disdrometers to gain information on drop size distributions (DSDs) and fall speeds. Analysis of disdrometer data in conjunction with radar data presented using Contour Frequency by Altitude Diagrams (CFADs) and high-resolution radiosonde data allows for a structural comparison of PECAN MCS cases to previously identified MCS archetypes. Novel insights into the structural evolution of nocturnal MCSs in relation to their synoptic, mesoscale, and thermodynamic environments are presented, using data collected from dense and numerous observation platforms. Understanding the environmental conditions that result in different nocturnal MCS configurations is useful for gaining insight into precipitation distributions and potential severe weather and flooding hazards in the Great Plains.

  12. The pecan nut (Carya illinoinensis) and its oil and polyphenolic fractions differentially modulate lipid metabolism and the antioxidant enzyme activities in rats fed high-fat diets.

    Science.gov (United States)

    Domínguez-Avila, Jesús A; Alvarez-Parrilla, Emilio; López-Díaz, José A; Maldonado-Mendoza, Ignacio E; Gómez-García, María Del Consuelo; de la Rosa, Laura A

    2015-02-01

    Tree nuts such as pecans (Carya illinoinensis) contain mostly oil but are also a source of polyphenols. Nut consumption has been linked to a reduction in serum lipid levels and oxidative stress. These effects have been attributed to the oil while overlooking the potential contribution of the polyphenols. Because the evidence regarding each fraction's bioactivity is scarce, we administered high-fat (HF) diets to male Wistar rats, supplementing them with pecan oil (HF+PO), pecan polyphenols (HF+PP) or whole pecans (HF+WP), and analysed the effects of each fraction. The HF diet increased the serum leptin and total cholesterol (TC) with respect to the control levels. The HF+WP diet prevented hyperleptinemia and decreased the TC compared with the control. The HF+WP diet upregulated the hepatic expression of apolipoprotein B and LDL receptor mRNAs with respect to the HF levels. The HF+PO diet reduced the level of triacylglycerols compared with the control. The HF+PP diet stimulated the hepatic expression of liver X receptor alpha mRNA. The HF+WP diet increased the activities of hepatic catalase, glutathione peroxidase and glutathione S transferase compared with the control, and decreased the degree of lipid peroxidation compared with the HF diet. The most bioactive diet was the WP diet. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. A comparison of ground-based air-blast sprayer and aircraft application of fungicides to manage scab in tall pecan trees

    Science.gov (United States)

    Scab (caused by Venturia effusa) is the most destructive disease of pecan in the southeastern USA. The most widely used method to apply fungicide is air-blast (AB) sprayers. Aerially (A) applied sprays are also used, but the disease distribution and spray coverage of these two methods has not been c...

  14. Characteristics of spray coverage from an air-blast sprayer, and why this is of concern for disease control in tall pecan trees

    Science.gov (United States)

    Application of fungicide sprays to pecan trees is challenging due to the height of the canopy above ground and the limitations of the ground-based spray application equipment (usually orchard air-blast sprayers). We describe results of experiments at the USDA, Byron, GA that were aimed to characteri...

  15. Shell Buckling Knockdown Factors

    Data.gov (United States)

    National Aeronautics and Space Administration — The Shell Buckling Knockdown Factor (SBKF) Project, NASA Engineering and Safety Center (NESC) Assessment #: 07-010-E, was established in March of 2007 by the NESC in...

  16. Shells and Patterns

    Science.gov (United States)

    Sutley, Jane

    2009-01-01

    "Shells and Patterns" was a project the author felt would easily put smiles on the faces of her fifth-graders, and teach them about unity and the use of watercolor pencils as well. It was thrilling to see the excitement in her students as they made their line drawings of shells come to life. For the most part, they quickly got the hang of…

  17. The theory of spherically symmetric thin shells in conformal gravity

    Science.gov (United States)

    Berezin, Victor; Dokuchaev, Vyacheslav; Eroshenko, Yury

    The spherically symmetric thin shells are the nearest generalizations of the point-like particles. Moreover, they serve as the simple sources of the gravitational fields both in General Relativity and much more complex quadratic gravity theories. We are interested in the special and physically important case when all the quadratic in curvature tensor (Riemann tensor) and its contractions (Ricci tensor and scalar curvature) terms are present in the form of the square of Weyl tensor. By definition, the energy-momentum tensor of the thin shell is proportional to Diracs delta-function. We constructed the theory of the spherically symmetric thin shells for three types of gravitational theories with the shell: (1) General Relativity; (2) Pure conformal (Weyl) gravity where the gravitational part of the total Lagrangian is just the square of the Weyl tensor; (3) Weyl-Einstein gravity. The results are compared with these in General Relativity (Israel equations). We considered in detail the shells immersed in the vacuum. Some peculiar properties of such shells are found. In particular, for the traceless ( = massless) shell, it is shown that their dynamics cannot be derived from the matching conditions and, thus, is completely arbitrary. On the contrary, in the case of the Weyl-Einstein gravity, the trajectory of the same type of shell is completely restored even without knowledge of the outside solution.

  18. Survival of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes on raw peanut and pecan kernels stored at -24, 4, and 22°C.

    Science.gov (United States)

    Brar, Pardeepinder K; Proano, Lisseth G; Friedrich, Loretta M; Harris, Linda J; Danyluk, Michelle D

    2015-02-01

    Cocktails of lawn-collected cells were used to determine the survival of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes on the surface of raw peanut and pecan kernels. Kernels were inoculated with mixtures of four to five strains at 3 or 6 log CFU/g, dried at room temperature, and then stored at -24 ± 1, 4 ± 2, and 22 ± 1°C for 28 or 365 days. In most cases, rates of decline of the pathogens did not differ significantly between the two inoculum concentrations in the 28-day study. At 6 log CFU/g, populations of all pathogens were reduced by 0.5 to 1.6 log CFU/g during an initial 3-day drying period on both peanuts and pecans. The moisture content of peanuts and pecans remained stable at -24 ± 1 and 22 ± 1°C; at 4 ± 2°C, the moisture content increased from 3.8 to 5.6% on peanuts and from 2.6 to 3% on pecans over 365 days. Pathogen populations were stable on pecans stored under frozen and refrigerated conditions, except for L. monocytogenes, which declined at a rate of 0.03 log CFU/g/30 days at 4 ± 2°C. Salmonella populations were stable on peanuts stored at -24 ± 1 and 4 ± 2°C, but E. coli O157:H7 and L. monocytogenes declined at rates of 0.03 to 0.12 log CFU/g/30 days. At 22 ± 1°C, Salmonella, E. coli O157:H7, and L. monocytogenes declined at a rate of 0.22, 0.37, and 0.59 log CFU/g/30 days, respectively, on peanuts, and at 0.15, 0.34, and 1.17 log CFU/g/30 days, respectively, on pecans. Salmonella counts were above the limit of detection (0.30 log CFU/g) throughout the study. In most cases during storage, counts obtained from pecans were higher than from peanuts.

  19. Off-shell CHY amplitudes

    Energy Technology Data Exchange (ETDEWEB)

    Lam, C.S., E-mail: Lam@physics.mcgill.ca [Department of Physics, McGill University, Montreal, Q.C., H3A 2T8 (Canada); Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Yao, York-Peng, E-mail: yyao@umich.edu [Department of Physics, The University of Michigan Ann Arbor, MI 48109 (United States)

    2016-06-15

    The Cachazo–He–Yuan (CHY) formula for on-shell scattering amplitudes is extended off-shell. The off-shell amplitudes (amputated Green's functions) are Möbius invariant, and have the same momentum poles as the on-shell amplitudes. The working principles which drive the modifications to the scattering equations are mainly Möbius covariance and energy momentum conservation in off-shell kinematics. The same technique is also used to obtain off-shell massive scalars. A simple off-shell extension of the CHY gauge formula which is Möbius invariant is proposed, but its true nature awaits further study.

  20. The development of the super-biodiesel production continuously from Sunan pecan oil through the process of reactive distillation

    Science.gov (United States)

    Yohana, Eflita; Yulianto, Moh. Endy; Ikhsan, Diyono; Nanta, Aditya Marga; Puspitasari, Ristiyanti

    2016-06-01

    In general, a vegetable oil-based biodiesel production commercially operates a batch process with high investments and operational costs. Thus, it is necessary to develop super-biodiesel production from sunan pecan oil continuously through the process of reactive distillation. There are four advantages of the reactive distillation process for the biodiesel production, as follows: (i) it incorporates the process of transesterification reaction, and product separation of residual reactants become one stage of the process, so it saves the investment and operation costs, (ii) it reduces the need for raw materials because the methanol needed corresponds to the stoichiometry, so it also reduces the operation costs, (iii) the holdup time in the column is relatively short (5±0,5 minutes) compared to the batch process (1-2 hours), so it will reduce the operational production costs, and (iv) it is able to shift the reaction equilibrium, because the products and reactants that do not react are instantly separated (based on Le Chatelier's principles) so the conversion will be increased. However, the very crucial problem is determining the design tools and process conditions in order to maximize the conversion of the transesterification reaction in both phases. Thus, the purpose of this research was to design a continuous reactive distillation process by using a recycled condensate to increase the productivity of the super-biodiesel from sunan pecan oil. The research was carried out in three stages including (i) designing and fabricating the reactive distillation equipment, (ii) testing the tool performance and the optimization of the biodiesel production, and (iii) biodiesel testing on the diesel engine. These three stages were needed in designing and scaling-up the process tools and the process operation commercially. The reactive distillation process tools were designed and manufactured with reference to the design system tower by Kitzer, et.al. (2008). The manufactured

  1. NIF Double Shell outer/inner shell collision experiments

    Science.gov (United States)

    Merritt, E. C.; Loomis, E. N.; Wilson, D. C.; Cardenas, T.; Montgomery, D. S.; Daughton, W. S.; Dodd, E. S.; Desjardins, T.; Renner, D. B.; Palaniyappan, S.; Batha, S. H.; Khan, S. F.; Smalyuk, V.; Ping, Y.; Amendt, P.; Schoff, M.; Hoppe, M.

    2017-10-01

    Double shell capsules are a potential low convergence path to substantial alpha-heating and ignition on NIF, since they are predicted to ignite and burn at relatively low temperatures via volume ignition. Current LANL NIF double shell designs consist of a low-Z ablator, low-density foam cushion, and high-Z inner shell with liquid DT fill. Central to the Double Shell concept is kinetic energy transfer from the outer to inner shell via collision. The collision determines maximum energy available for compression and implosion shape of the fuel. We present results of a NIF shape-transfer study: two experiments comparing shape and trajectory of the outer and inner shells at post-collision times. An outer-shell-only target shot measured the no-impact shell conditions, while an `imaging' double shell shot measured shell conditions with impact. The `imaging' target uses a low-Z inner shell and is designed to perform in similar collision physics space to a high-Z double shell but can be radiographed at 16keV, near the viable 2DConA BL energy limit. Work conducted under the auspices of the U.S. DOE by LANL under contract DE-AC52-06NA25396.

  2. Sidewall coring shell

    Energy Technology Data Exchange (ETDEWEB)

    Edelman, Ya A; Konstantinov, L P; Martyshin, A N

    1966-12-12

    A sidewall coring shell consists of a housing and a detachable core catcher. The core lifter is provided with projections, the ends of which are situated in another plane, along the longitudinal axis of the lifter. The chamber has corresponding projections.

  3. Phenolic compounds and antioxidant activity of Pecan [Carya illinoinensis (Wangenh. C. Koch] kernel cake extracts obtained by sequential extraction

    Directory of Open Access Journals (Sweden)

    Block, Jane Mara

    2009-12-01

    Full Text Available The total phenolic and condensed tannin contents of different Pecan kernel cake extracts (ether, acetone, alcohol and distilled water were estimated and their antioxidant activities were evaluated through ABTS, DPPH and ß-carotene/linoleic acid systems. Color variations of the Pecan kernel cake were determined through an instrumental analysis using the CIE Lab system. Significantly higher levels (p El contenido de taninos condensado y fenoles totales de diferentes extractos de tortas de almendra de pecana (éter, acetona, alcohol y agua destilada fueron estimados y sus actividades antioxidantes fueron evaluadas mediantes los métodos con ABTS, DPPH y el sistema ß-caroteno/ácido linoleico. Las variaciones de color de la torta de almendra de pecana fueron determinadas mediante análisis instrumental usando el sistema CIE Lab. Los contenidos de fenoles totales, taninos condensados y actividad antioxidante, medida mediante los métodos con ABTS Y DPPH (30 min y 24 h, fueron significativamente más altos (p < 0.05 con el extracto de acetona (16.4 mg GAE/g; 31.2 mg CE/g; 235.3 μmol TEAC/g and 68.6 and 100.3 mg TEAC/g, respectivamente. El porcentaje de inhibición de la oxidación en el sistema ß-caroteno/ ácido linoleico vario desde 37.9 a 93.1% con el extracto de acetona a 300 ppm, mostrando resultados significativamente superiores. Las muestras con una mayor tendencia a tonos rojos presento los niveles más altos de taninos condensados.

  4. Stability of charged thin shells

    International Nuclear Information System (INIS)

    Eiroa, Ernesto F.; Simeone, Claudio

    2011-01-01

    In this article we study the mechanical stability of spherically symmetric thin shells with charge, in Einstein-Maxwell and Einstein-Born-Infeld theories. We analyze linearized perturbations preserving the symmetry, for shells around vacuum and shells surrounding noncharged black holes.

  5. Temporal structures in shell models

    DEFF Research Database (Denmark)

    Okkels, F.

    2001-01-01

    The intermittent dynamics of the turbulent Gledzer, Ohkitani, and Yamada shell-model is completely characterized by a single type of burstlike structure, which moves through the shells like a front. This temporal structure is described by the dynamics of the instantaneous configuration of the shell...

  6. Market analysis of food products for detection of allergenic walnut (Juglans regia) and pecan (Carya illinoinensis) by real-time PCR.

    Science.gov (United States)

    López-Calleja, Inés María; de la Cruz, Silvia; González, Isabel; García, Teresa; Martín, Rosario

    2015-06-15

    Two real-time polymerase chain reaction (PCR)-based assays for detection of walnut (Juglans regia) and pecan (Carya illinoinensis) traces in a wide range of processed foods are described here. The method consists on a real-time PCR assay targeting the ITS1 region, using a nuclease (TaqMan) probe labeled with FAM and BBQ. The method was positive for walnut and pecan respectively, and negative for all other heterologous plants and animals tested. Using a series of model samples with defined raw walnut in wheat flour and heat-treated walnut in wheat flour with a range of concentrations of 0.1-100,000 mg kg(-1), a practical detection limit of 0.1 mg kg(-1) of walnut content was estimated. Identical binary mixtures were done for pecan, reaching the same limit of detection of 0.1 mg kg(-1). The assay was successfully trialed on a total of 232 commercial foodstuffs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Four-loop relation between the MS and on-shell quark mass

    International Nuclear Information System (INIS)

    Marquard, Peter; Smirnov, Alexander V.; Smirnov, Vladimir A.; Steinhauser, Matthias

    2016-01-01

    In this contribution we discuss the four-loop relation between the on-shell and MS definition of heavy quark masses which is applied to the top, bottom and charm case. We also present relations between the MS quark mass and various threshold mass definitions and discuss the uncertainty at next-to-next-to-next-to-leading order.

  8. Shells on elastic foundations

    International Nuclear Information System (INIS)

    Das, Y.C.; Kedia, K.K.

    1977-01-01

    No realistic analytical work in the area of Shells on Elastic Foundations has been reported in the literature. Various foundation models have been proposed by several authors. These models involve one or more than one parameters to characterise the foundation medium. Some of these models cannot be used to derive the basic equations governing the behaviour of shells on elastic foundations. In the present work, starting from an elastic continuum hypothesis, a mathematical model for foundation has been derived in curvilinear orthogonal coordinates by the help of principle of virtual displacements, treating one of the virtual displacements as known to satisfy certain given conditions at its edge surfaces. In this model, several foundation parameters can be considered and it can also be used for layered medium of both finite and infinite thickness. (Auth.)

  9. Buckling strength of spherical shells under combined loads

    International Nuclear Information System (INIS)

    Nagashima, H.; Kokubo, K.; Takayanagi, M.; Hayasaka, Y.; Kume, T.; Nagata, T.

    1995-01-01

    Many studies on buckling of cylindrical shells have been conducted, and many buckling evaluation equations have been proposed for actual plant designs; however, buckling of spherical shells under combined horizontal and vertical loads cannot be evaluated due to insufficient data. There is a particular lack of buckling data for spherical shells under lateral loads. To establish a method for estimating the buckling strength of spherical shells, we investigate the interactions between horizontal and vertical (compressive tensile) loads by conducting buckling tests. Applying several combinations of these loads in tests and using computer linear analysis, we obtain interaction curves. This study reports on the buckling tests conducted using spherical shell 1120 mm in dia., 0.7 mm thick and 696 mm high, which are shaped individually by press-forming and finally joined together by four meridional welds, using a specially made jig. Initial imperfections before testing and local deformations after each loading increment during testing are measured with special measuring equipment, and the interaction curve of horizontal and vertical loads and effect of imperfection on the buckling strength of spherical shells are obtained. Nonlinear FEM programs are developed using an 8-node isoparametric shell element and a four-node quadrilateral element of C 0 type with reduced integration based upon a Mindlin-Reissner theory which includes transverse shear. Actual initial imperfections are generally in irregular patterns. Thus, there may be several definitions of the equivalent magnitudes of initial imperfections related to buckling loads. Equivalent magnitudes have no practical meaning unless they can be obtained easily not only for small structures such as test shells but also for large actual structures. In the present study, we define the equivalent magnitude of initial imperfections as the maximum local ruggedness measured radially from a circular temperature having a radius equal

  10. Wrinkling of Pressurized Elastic Shells

    KAUST Repository

    Vella, Dominic

    2011-10-01

    We study the formation of localized structures formed by the point loading of an internally pressurized elastic shell. While unpressurized shells (such as a ping-pong ball) buckle into polygonal structures, we show that pressurized shells are subject to a wrinkling instability. We study wrinkling in depth, presenting scaling laws for the critical indentation at which wrinkling occurs and the number of wrinkles formed in terms of the internal pressurization and material properties of the shell. These results are validated by numerical simulations. We show that the evolution of the wrinkle length with increasing indentation can be understood for highly pressurized shells from membrane theory. These results suggest that the position and number of wrinkles may be used in combination to give simple methods for the estimation of the mechanical properties of highly pressurized shells. © 2011 American Physical Society.

  11. Seismic analysis of axisymmetric shells

    International Nuclear Information System (INIS)

    Jospin, R.J.; Toledo, E.M.; Feijoo, R.A.

    1984-01-01

    Axisymmetric shells subjected to multiple support excitation are studied. The shells are spatialy discretized by the finite element method and in order to obtain estimates for the maximum values of displacements and stresses the response spectrum tecnique is used. Finally, some numerical results are presented and discussed in the case of a shell of revolution with vertical symmetry axis, subjected to seismic ground motions in the horizontal, vertical and rocking directions. (Author) [pt

  12. Creep analysis of orthotropic shells

    International Nuclear Information System (INIS)

    Mehra, V.K.; Ghosh, A.

    1975-01-01

    A method of creep analysis of orthotropic cylindrical shells subjected to axisymmetric loads has been developed. A general study of creep behaviour of cylindrical shells subjected to a uniform internal pressure has been conducted for a wide range of values of anisotropy coefficients and creep law exponent. Analysis includes determination of stress re-distribution, strain rates, stationary state stresses. Application of reference stress technique has been extended to analysis of shells. (author)

  13. The direct manipulation shell

    International Nuclear Information System (INIS)

    Allen, M.E.; Christiansen, M.

    1992-01-01

    Accelerator controls systems provide parameter display pages which allow the operator to monitor and manipulate selected control points in the system. Display pages are generally implemented as either hand-crafted, purpose-built programs; or by using a specialized display page layout tool. These two methods of display page development exhibit the classic trade-off between functionality vs. ease of implementation. In the Direct Manipulation Shell we approach the process of developing a display page in a manifestly object-oriented manner. This is done by providing a general framework for interactively instantiating and manipulating display objects. (author)

  14. Plate shell structures of glass

    DEFF Research Database (Denmark)

    Bagger, Anne

    to their curved shape. A plate shell structure maintains a high stiffness-to-weight ratio, while facilitating the use of plane structural elements. The study focuses on using laminated glass panes for the load bearing facets. Various methods of generating a plate shell geometry are suggested. Together with Ghent......, such as facet size, imperfections, and connection characteristics. The critical load is compared to that of a similar, but smoothly curved, shell structure. Based on the investigations throughout the study, a set of guidelines for the structural design of plate shells of glass is proposed....

  15. Dossier Shell Eco-Marathon; Dossier Shell Eco-Marathon

    Energy Technology Data Exchange (ETDEWEB)

    Matla, P.

    2012-05-15

    Three articles address subjects concerning the annual race with highly energy efficient cars: the Shell Eco-Marathon. [Dutch] In 3 artikelen wordt aandacht besteed aan de ontwerpen voor de jaarlijkse race met superzuinige auto's, de Shell Eco-Marathon.

  16. Hi shells, supershells, shell-like objects, and ''worms''

    International Nuclear Information System (INIS)

    Heiles, C.

    1984-01-01

    We present photographic representations of the combination of two Hi surveys, so as to eliminate the survey boundaries at Vertical BarbVertical Bar = 10 0 . We also present high-contrast photographs for particular velocities to exhibit weak Hi features. All of these photographs were used to prepare a new list of Hi shells, supershells, and shell-like objects. We discuss the structure of three shell-like objects that are associated with high-velocity gas, and with gas at all velocities that is associated with radio continuum loops I, II, and III. We use spatial filtering to find wiggly gas filaments: ''worms'': crawling away from the galactic plane in the inner Galaxy. The ''worms'' are probably parts of shells that are open at the top; such shells should be good sources of hot gas for the galactic halo

  17. The performance and emissions of diesel engines with biodiesel of sunan pecan seed and diesel oil blends

    Science.gov (United States)

    Ariani, F.; Sitorus, T. B.; Ginting, E.

    2017-12-01

    An observation was performed to evaluate the performance of direct injection stationary diesel engine which used a blends of biodiesel of Sunan pecan seed. The experiments were done with diesel oil, B5, B10, B15 and B20 in the engine speed variety. Results showed that the values of torque, power and thermal efficiency tend to decrease when the engine is using B5, B10, B15 and B20, compared to diesel oil. It also shown that the specific fuel consumption is increased when using B5, B10, B15 and B20. From the results of experiments and calculations, the maximum power of 3.08 kW, minimum specific fuel consumption of 189.93 g/kWh and maximum thermal efficiency of 45.53% when engine using diesel oil. However, exhaust gases were measured include opacity, carbon monoxide and hydrocarbon when the engine using biodiesel B5, B10, B15 and B20 decreased.

  18. Characterization of macadamia and pecan oils and detection of mixtures with other edible seed oils by Raman spectroscopy

    Directory of Open Access Journals (Sweden)

    Carmona, M. A.

    2015-09-01

    Full Text Available Authenticating fats and detecting their adulteration with substantially cheaper fats can pose major problems for producers of high-value oils for nutritional and cosmetic use. In this work, we used Raman spectroscopy to discriminate macadamia and pecan oils from other, cheaper vegetable oils including corn and sunflower oils. This technique additionally allows one to detect and assess the adulteration of macadamia oil with another vegetable oil.La autentificación de grasas para detectar su adulteración con otras grasas más baratas es uno de los principales problemas a los que se enfrentan los productores de aceites de alto valor, ya sea para uso alimentario o para uso cosmético. En este trabajo se emplea la espectroscopia Raman, por un lado, para caracterizar los aceites de macadania y de nuez pecanera, de alto valor y diferenciarlos de otros más baratos, como los de maíz y de girasol, y por otro, para detectar mezclas del aceite de macadamia con estos aceites vegetales más baratos.

  19. Evidence for the presence of a bacterial endosymbiont in the pecan scab pathogen Venturia effusa (basyonym: Fusicladium effusum).

    Science.gov (United States)

    Medrano, E G; Grauke, L J; Stanford, R L; Thompson, T E

    2017-08-01

    To determine whether Venturia effusa, the causative fungal agent of pecan scab, harbours a bacterial symbiont. Venturia effusa isolates were maintained on potato dextrose agar amended with antibiotics (chloramphenicol (100 μg ml -1 ) and tetracycline 100 (μg ml -1 )). Genomic DNA extracted from mycelia was used to target eubacterial 16S rDNA. A 1·4-kbp PCR amplified product using 16S rDNA degenerate primers was cloned, sequenced and found to have 99% identities with Actinobacteria representatives. Attempts to culture the detected bacteria apart from the fungus following agitation and fungal cell lysis were unsuccessful using standard bacteriological media under either aerobic or anaerobic conditions. Fungal structures were visualized using scanning electron microscopy and putative bacterial formations associated with the fungal mycelia were observed. Fluorescence in situ hybridization using 16S rDNA oligonucleotides illuminated spores and portions of the hyphae. This is the first report to provide both molecular microbiological and microscopic evidence in support of the hypothesis that V. effusa harbours endosymbiotic bacteria. Findings from this research contribute fundamental information regarding the biology of the fungus that may ultimately lead to identifying a target of the pathogen for use in management and/or avoidance strategies. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  20. Pecan nutshell as biosorbent to remove Cu(II), Mn(II) and Pb(II) from aqueous solutions.

    Science.gov (United States)

    Vaghetti, Julio C P; Lima, Eder C; Royer, Betina; da Cunha, Bruna M; Cardoso, Natali F; Brasil, Jorge L; Dias, Silvio L P

    2009-02-15

    In the present study we reported for the first time the feasibility of pecan nutshell (PNS, Carya illinoensis) as an alternative biosorbent to remove Cu(II), Mn(II) and Pb(II) metallic ions from aqueous solutions. The ability of PNS to remove the metallic ions was investigated by using batch biosorption procedure. The effects such as, pH, biosorbent dosage on the adsorption capacities of PNS were studied. Four kinetic models were tested, being the adsorption kinetics better fitted to fractionary-order kinetic model. Besides that, the kinetic data were also fitted to intra-particle diffusion model, presenting three linear regions, indicating that the kinetics of adsorption should follow multiple sorption rates. The equilibrium data were fitted to Langmuir, Freundlich, Sips and Redlich-Peterson isotherm models. Taking into account a statistical error function, the data were best fitted to Sips isotherm model. The maximum biosorption capacities of PNS were 1.35, 1.78 and 0.946mmolg(-1) for Cu(II), Mn(II) and Pb(II), respectively.

  1. A classification system for pressure vessel shell failures

    International Nuclear Information System (INIS)

    Harrop, L.P.

    1989-01-01

    A system for classifying failures of the shells of pressure vessels is presented. The classification system is based on the way a failure physically manifests itself and not on imputed economic or safety significance. It is believed the described way of classifying the failures is useful for transferring information from one situation to another. In assigning names to types of failure, the intention has been to adopt explicit definitions rather than supposed colloquial usage. (author)

  2. Shell Trumpets from Western Mexico

    Directory of Open Access Journals (Sweden)

    Robert Novella

    1991-11-01

    Full Text Available Marine shells have been used as musical instruments in almost all parts of the world (Izikowitz 1935, including Mesoamerica, where large univalves, also called conch shells in the literature, had a utilitarian function as trumpets. Their use is well documented in most cultural areas of Mesoamerica, as in Western Mexico, through their various occurrences in archaeological contexts and museums collections.

  3. Cylindrical thin-shell wormholes

    International Nuclear Information System (INIS)

    Eiroa, Ernesto F.; Simeone, Claudio

    2004-01-01

    A general formalism for the dynamics of nonrotating cylindrical thin-shell wormholes is developed. The time evolution of the throat is explicitly obtained for thin-shell wormholes whose metric has the form associated with local cosmic strings. It is found that the throat collapses to zero radius, remains static, or expands forever, depending only on the sign of its initial velocity

  4. Shell model and spectroscopic factors

    International Nuclear Information System (INIS)

    Poves, P.

    2007-01-01

    In these lectures, I introduce the notion of spectroscopic factor in the shell model context. A brief review is given of the present status of the large scale applications of the Interacting Shell Model. The spectroscopic factors and the spectroscopic strength are discussed for nuclei in the vicinity of magic closures and for deformed nuclei. (author)

  5. Conventional shell model: some issues

    International Nuclear Information System (INIS)

    Vallieres, M.; Pan, X.W.; Feng, D.H.; Novoselsky, A.

    1997-01-01

    We discuss some important issues in shell-model calculations related to the effective interactions used in different regions of the periodic table; in particular the quality of different interactions is discussed, as well as the mass dependence of the interactions. Mention is made of the recently developed Drexel University shell-model (DUSM). (orig.)

  6. Expert system development (ESD) shell

    International Nuclear Information System (INIS)

    Padmini, S.; Diwakar, M.P.; Rathode, N.C.; Bairi, B.R.

    1991-01-01

    An Expert System Development (ESD) Shell design implementation is desribed in detail. The shell provides high-level generic facilities for Knowledge Representation (KR) and inferencing and tools for developing user interfaces. Powerful set of tools in the shell relieves much of the programming burden in the ES development. The shell is written in PROLOG under IBM PC/AT. KR facilities are based on two very powerful formalisms namely, frames and rules. Inference Engine (IE) draws most of its power from unification and backward reasoning strategy in PROLOG. This basic mechanism is enhanced further by incorporating both forward and backward chaining of rules and frame-based inferencing. Overall programming style integrates multiple paradigms including logic, object oriented, access-oriented and imperative programming. This permits ES designer a lot of flexibility in organizing inference control. Creation and maintainance of knowledge base is a major activity. The shell, therefore, provides number of facilities to simplify these tasks. Shell design also takes note of the fact that final success of any system depends on end-user satisfaction and hence provides features to build use-friendly interfaces. The shell also provides a set of interfacing predicates so that it can be embedded within any PROLOG program to incorporate functionalilty of the shell in the user program. (author). 10 refs., 8 figs

  7. Dynamic centering of liquid shells

    International Nuclear Information System (INIS)

    Tsamopoulos, J.A.; Brown, R.A.

    1987-01-01

    The moderate-amplitude axisymmetric oscillations of an inviscid liquid shell surrounding an incompressible gas bubble are calculated by a multiple-time-scale expansion for initial deformations composed of two-lobed perturbations of the shell and a displacement of the bubble from the center of mass of the liquid. Two types of small-amplitude motion are identified and lead to very different nonlinear dynamic interactions, as described by the results valid up to second order in the amplitude of the initial deformation. In the ''bubble mode,'' the oscillations of the captive bubble and the liquid shell are exactly in phase and the bubble vibrates about its initial eccentric location. The bubble moves toward the center of the drop when the shell is perturbed into a ''sloshing mode'' of oscillation where both interfaces move out of phase. These results explain the centering of liquid shells observed in several experiments

  8. Absorption of SO/sub 2/ by pecan (Carya illinoensis (Wang) K. Koch) and alfalfa (Medicago sativa L. ) and its effect on net photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Sisson, W.B.; Booth, J.A.; Throneberry, G.O.

    1981-06-01

    Absorption rates of SO/sub 2/ by pecan (Carya illinoensis (Wang) K. Koch) leaflets exposed to 2.6, 5.2, and 7.8 mg SO/sub 2/ m/sup -3/ were measured over a 2 h period. SO/sub 2/ was rapidly absorbed by the leaflets in all treatments during the initial 30-50 min; the rate of uptake decreased to a rather constant level thereafter. Total SO/sub 2/ absorbed during the 2 h period was 15.6, 25.6, and 38.9 nmol cm/sup -2/ for the low, medium, and high SO/sub 2/ concentrations, respectively. Reductions in net photosynthetic rates were proportional to ambient SO/sub 2/ concentrations and total SO/sub 2/ absorbed. Partial photosynthetic recovery occurred in all treatments during a 2 hr post-treatment period and full recovery occurred during a 12 h dark period. Exposure to SO/sub 2/ resulted in slight increases in stomatal and boundary layer resistances to CO/sub 2/ and substantial increases in residual resistances. Absorption rates of SO/sub 2/ by alfalfa (Medicago sativa L.) exposed to 5.2 mg SO/sub 2/ m/sup -3/ for 1 h were approximately double those of pecan exposed to the same ambient SO/sub 2/ concentration. Alfalfa net photosynthetic rates were reduced 74% after 1 h exposure to 5.2 mg SO/sub 2/ m/sup -3/ while a depression of 42% occurred in pecan.

  9. Molluscan shell evolution with review of shell calcification hypothesis

    Czech Academy of Sciences Publication Activity Database

    Furuhashi, T.; Schwarzinger, C.; Mikšík, Ivan; Smrž, Miloslav; Beran, A.

    2009-01-01

    Roč. 154, č. 3 (2009), s. 351-371 ISSN 1096-4959 Institutional research plan: CEZ:AV0Z50110509 Keywords : mollusca * shell * biomineralization Subject RIV: CE - Biochemistry Impact factor: 1.607, year: 2009

  10. MicroShell Minimalist Shell for Xilinx Microprocessors

    Science.gov (United States)

    Werne, Thomas A.

    2011-01-01

    MicroShell is a lightweight shell environment for engineers and software developers working with embedded microprocessors in Xilinx FPGAs. (MicroShell has also been successfully ported to run on ARM Cortex-M1 microprocessors in Actel ProASIC3 FPGAs, but without project-integration support.) Micro Shell decreases the time spent performing initial tests of field-programmable gate array (FPGA) designs, simplifies running customizable one-time-only experiments, and provides a familiar-feeling command-line interface. The program comes with a collection of useful functions and enables the designer to add an unlimited number of custom commands, which are callable from the command-line. The commands are parameterizable (using the C-based command-line parameter idiom), so the designer can use one function to exercise hardware with different values. Also, since many hardware peripherals instantiated in FPGAs have reasonably simple register-mapped I/O interfaces, the engineer can edit and view hardware parameter settings at any time without stopping the processor. MicroShell comes with a set of support scripts that interface seamlessly with Xilinx's EDK tool. Adding an instance of MicroShell to a project is as simple as marking a check box in a library configuration dialog box and specifying a software project directory. The support scripts then examine the hardware design, build design-specific functions, conditionally include processor-specific functions, and complete the compilation process. For code-size constrained designs, most of the stock functionality can be excluded from the compiled library. When all of the configurable options are removed from the binary, MicroShell has an unoptimized memory footprint of about 4.8 kB and a size-optimized footprint of about 2.3 kB. Since MicroShell allows unfettered access to all processor-accessible memory locations, it is possible to perform live patching on a running system. This can be useful, for instance, if a bug is

  11. Comparison of Ground- and Space-based Radar Observations with Disdrometer Measurements During the PECAN Field Campaign

    Science.gov (United States)

    Torres, A. D.; Rasmussen, K. L.; Bodine, D. J.; Dougherty, E.

    2015-12-01

    Plains Elevated Convection At Night (PECAN) was a large field campaign that studied nocturnal mesoscale convective systems (MCSs), convective initiation, bores, and low-level jets across the central plains in the United States. MCSs are responsible for over half of the warm-season precipitation across the central U.S. plains. The rainfall from deep convection of these systems over land have been observed to be underestimated by satellite radar rainfall-retrieval algorithms by as much as 40 percent. These algorithms have a strong dependence on the generally unmeasured rain drop-size distribution (DSD). During the campaign, our group measured rainfall DSDs, precipitation fall velocities, and total precipitation in the convective and stratiform regions of MCSs using Ott Parsivel optical laser disdrometers. The disdrometers were co-located with mobile pod units that measured temperature, wind, and relative humidity for quality control purposes. Data from the operational NEXRAD radar in LaCrosse, Wisconsin and space-based radar measurements from a Global Precipitation Measurement satellite overpass on July 13, 2015 were used for the analysis. The focus of this study is to compare DSD measurements from the disdrometers to radars in an effort to reduce errors in existing rainfall-retrieval algorithms. The error analysis consists of substituting measured DSDs into existing quantitative precipitation estimation techniques (e.g. Z-R relationships and dual-polarization rain estimates) and comparing these estimates to ground measurements of total precipitation. The results from this study will improve climatological estimates of total precipitation in continental convection that are used in hydrological studies, climate models, and other applications.

  12. Effect of Soil Moisture and a Surfactant on Entomopathogenic Nematode Suppression of the Pecan Weevil, Curculio caryae

    Science.gov (United States)

    Shapiro-Ilan, David I.; Cottrell, Ted E.; Brown, Ian; Gardner, Wayne A.; Hubbard, Robert K.; Wood, Bruce W.

    2006-01-01

    Our overall goal was to investigate several aspects of pecan weevil, Curculio caryae, suppression with entomopathogenic nematodes. Specifically, our objectives were to: 1) determine optimum moisture levels for larval suppression, 2) determine suppression of adult C. caryae under field conditions, and 3) measure the effects of a surfactant on nematode efficacy. In the laboratory, virulence of Heterorhabditis megidis (UK211) and Steinernema carpocapsae (All) were tested in a loamy sand at gravimetric water contents of negative 0.01, 0.06, 0.3, 1.0, and 15 bars. Curculio caryae larval survival decreased as moisture levels increased. The nematode effect was most pronounced at –0.06 bars. At –0.01 bars, larval survival was ≤5% regardless of nematode presence, thus indicating that intense irrigation alone might reduce C. caryae populations. Overall, our results indicated no effect of a surfactant (Kinetic) on C. caryae suppression with entomopathogenic nematodes. In a greenhouse test, C. caryae larval survival was lower in all nematode treatments compared with the control, yet survival was lower in S. carpocapsae (Italian) and S. riobrave (7–12) treatments than in S. carpocapsae (Agriotos), S. carpocapsae (Mexican), and S. riobrave (355) treatments (survival was reduced to approximately 20% in the S. riobrave [7–12] treatment). A mixture of S. riobrave strains resulted in intermediate larval survival. In field experiments conducted over two consecutive years, S. riobrave (7–12) applications resulted in no observable control, and, although S. carpocapsae (Italian) provided some suppression, treatment effects were generally only detectable one day after treatment. Nematode strains possessing both high levels of virulence and a greater ability to withstand environmental conditions in the field need to be developed and tested. PMID:19259466

  13. Instant Windows PowerShell

    CERN Document Server

    Menon, Vinith

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. A practical, hands-on tutorial approach that explores the concepts of PowerShell in a friendly manner, taking an adhoc approach to each topic.If you are an administrator who is new to PowerShell or are looking to get a good grounding in these new features, this book is ideal for you. It's assumed that you will have some experience in PowerShell and Windows Server, as well being familiar with the PowerShell command-line.

  14. Patterning of the turtle shell.

    Science.gov (United States)

    Moustakas-Verho, Jacqueline E; Cebra-Thomas, Judith; Gilbert, Scott F

    2017-08-01

    Interest in the origin and evolution of the turtle shell has resulted in a most unlikely clade becoming an important research group for investigating morphological diversity in developmental biology. Many turtles generate a two-component shell that nearly surrounds the body in a bony exoskeleton. The ectoderm covering the shell produces epidermal scutes that form a phylogenetically stable pattern. In some lineages, the bones of the shell and their ectodermal covering become reduced or lost, and this is generally associated with different ecological habits. The similarity and diversity of turtles allows research into how changes in development create evolutionary novelty, interacting modules, and adaptive physiology and anatomy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. 40 Years of Shell Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-02-15

    Shell has been using scenario planning for four decades. During that time these scenarios have helped the company and governments across the world to make better strategic choices. Scenarios provide lenses that help see future prospects more clearly, make richer judgments and be more sensitive to uncertainties. Discover how the Shell Scenarios team has helped guide decision makers at major moments in history and get a peek at the team future focus, including the intricate relationship between energy, water and food.

  16. Electron-beam irradiation effects on phytochemical constituents and antioxidant capacity of pecan kernels [ Carya illinoinensis (Wangenh.) K. Koch] during storage.

    Science.gov (United States)

    Villarreal-Lozoya, Jose E; Lombardini, Leonardo; Cisneros-Zevallos, Luis

    2009-11-25

    Pecans kernels (Kanza and Desirable cultivars) were irradiated with 0, 1.5, and 3.0 kGy using electron-beam (E-beam) irradiation and stored under accelerated conditions [40 degrees C and 55-60% relative humidity (RH)] for 134 days. Antioxidant capacity (AC) using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) assays, phenolic (TP) and condensed tannin (CT) content, high-performance liquid chromatography (HPLC) phenolic profile, tocopherol content, peroxide value (PV), and fatty acid profiles were determined during storage. Irradiation decreased TP and CT with no major detrimental effects in AC. Phenolic profiles after hydrolysis were similar among treatments (e.g., gallic and ellagic acid, catechin, and epicatechin). Tocopherol content decreased with irradiation (>21 days), and PV increased at later stages (>55 days), with no change in fatty acid composition among treatments. Color lightness decreased, and a reddish brown hue developed during storage. A proposed mechanism of kernel oxidation is presented, describing the events taking place. In general, E-beam irradiation had slight effects on phytochemical constituents and could be considered a potential tool for pecan kernel decontamination.

  17. Penetration of UV-A, UV-B, blue, and red light into leaf tissues of pecan measured by a fiber optic microprobe system

    Science.gov (United States)

    Qi, Yadong; Bai, Shuju; Vogelmann, Thomas C.; Heisler, Gordon M.

    2003-11-01

    The depth of light penetration from the adaxial surfaces of the mature leaves of pecan (Carya illinoensis) was measured using a fiber optic microprobe system at four wavelengths: UV-B (310nm), UV-A (360 nm), blue light (430nm), and red light (680nm). The average thickness of the leaf adaxial epidermal layer was 15um and the total leaf thickness was 219um. The patterns of the light attenuation by the leaf tissues exhibited strong wavelength dependence. The leaf adaxial epidermal layer was chiefly responsible for absorbing the UV-A UV-B radiation. About 98% of 310 nm light was steeply attenuated within the first 5 um of the adaxial epidermis; thus, very little UV-B radiation was transmitted to the mesophyll tissues where contain photosynthetically sensitive sites. The adaxial epidermis also attenuated 96% of the UV-A radiation. In contrast, the blue and red light penetrated much deeper and was gradually attenutated by the leaves. The mesophyll tissues attenuated 17% of the blue light and 42% of the red light, which were available for photosynthesis use. Since the epidermal layer absorbed nearly all UV-B light, it acted as an effective filter screening out the harmful radiation and protecting photosynthetically sensitive tissues from the UV-B damage. Therefore, the epidermal function of the UV-B screening effectiveness can be regarded as one of the UV-B protection mechanisms in pecan.

  18. Isogeometric shell formulation based on a classical shell model

    KAUST Repository

    Niemi, Antti

    2012-09-04

    This paper constitutes the first steps in our work concerning isogeometric shell analysis. An isogeometric shell model of the Reissner-Mindlin type is introduced and a study of its accuracy in the classical pinched cylinder benchmark problem presented. In contrast to earlier works [1,2,3,4], the formulation is based on a shell model where the displacement, strain and stress fields are defined in terms of a curvilinear coordinate system arising from the NURBS description of the shell middle surface. The isogeometric shell formulation is implemented using the PetIGA and igakit software packages developed by the authors. The igakit package is a Python package used to generate NURBS representations of geometries that can be utilised by the PetIGA finite element framework. The latter utilises data structures and routines of the portable, extensible toolkit for scientific computation (PETSc), [5,6]. The current shell implementation is valid for static, linear problems only, but the software package is well suited for future extensions to geometrically and materially nonlinear regime as well as to dynamic problems. The accuracy of the approach in the pinched cylinder benchmark problem and present comparisons against the h-version of the finite element method with bilinear elements. Quadratic, cubic and quartic NURBS discretizations are compared against the isoparametric bilinear discretization introduced in [7]. The results show that the quadratic and cubic NURBS approximations exhibit notably slower convergence under uniform mesh refinement as the thickness decreases but the quartic approximation converges relatively quickly within the standard variational framework. The authors future work is concerned with building an isogeometric finite element method for modelling nonlinear structural response of thin-walled shells undergoing large rigid-body motions. The aim is to use the model in a aeroelastic framework for the simulation of flapping wings.

  19. Creep buckling of shells

    International Nuclear Information System (INIS)

    Stone, C.M.; Nickell, R.E.

    1977-01-01

    Because of the characteristics of LMFBR primary piping components (thin-walled, low pressure, high temperature), the designer must guard against creep buckling as a potential failure mode for certain critical regions, such as elbows, where structural flexibility and inelastic response may combine to concentrate deformation and cause instability. The ASME Boiler and Pressure Vessel Code, through its elevated temperature Code Case 1592 (Section III, Division 1) provides design rules for Class 1 components aimed at preventing creep buckling during the design life. A similar set of rules is being developed for Class 2 and 3 components at this time. One of the original concepts behind the creep buckling rules was that the variability in creep properties (especially due to the effects of prior heat treatment), the uncertainty about initial imperfections, and the lack of confirmed accuracy of design analysis meant that conservatism would be difficult to assure. As a result, a factor of ten on service life was required (i.e. analysis must show that, under service conditions that extrapolate the life of the component by ten times, creep buckling does not occur). Two obvious problems with this approach are that: first, the creep behavior must also be extrapolated (since most creep experiments are terminated at a small fraction of the design life, extrapolation of creep data is already an issue, irrespective of the creep buckling question); second the nonlinear creep analysis, which is very nearly prohibitively expensive for design life histograms, becomes even more costly. Analytical results for an aluminum cylindrical shell subjected to axial loads at elevated temperatures are used to examine the supposed equivalence of two types of time-dependent buckling safety factors - a factor of ten on service life and a factor of 1.5 on loading

  20. LD Definition.

    Science.gov (United States)

    Learning Disability Quarterly, 1987

    1987-01-01

    The position paper (1981) of the National Joint Committee on Learning Disabilities presents a revised definition of learning disabilities and identifies issues and concerns (such as the limitation to children and the exclusion clause) associated with the definition included in P.L. 94-142, the Education for All Handicapped Children Act. (DB)

  1. Foam shell project: Progress report

    International Nuclear Information System (INIS)

    Overturf, G.; Reibold, B.; Cook, B.; Schroen-Carey, D.

    1994-01-01

    The authors report on their work to produce a foam shell target for two possible applications: (1) as liquid-layered cryogenic target on Omega Upgrade, and (2) as a back-up design for the NIF. This target consists of a roughly 1 mm diameter and 100 μm thick spherical low-density foam shell surrounding a central void. The foam will be slightly overfilled with liquid D 2 or DT, the overfilled excess being symmetrically distributed on the inside of the shell and supported by thermal gradient techniques. The outside of the foam is overcoated with full density polymer which must be topologically smooth. The technology for manufacturing this style of foam shell involves microencapsulation techniques and has been developed by the Japanese at ILE. Their goal is to determine whether this technology can be successfully adapted to meet US ICF objectives. To this end a program of foam shell development has been initiated at LLNL in collaboration with both the General Atomics DOE Target Fabrication Contract Corporation and the Target Fabrication Group at LLE

  2. The evolution of mollusc shells.

    Science.gov (United States)

    McDougall, Carmel; Degnan, Bernard M

    2018-05-01

    Molluscan shells are externally fabricated by specialized epithelial cells on the dorsal mantle. Although a conserved set of regulatory genes appears to underlie specification of mantle progenitor cells, the genes that contribute to the formation of the mature shell are incredibly diverse. Recent comparative analyses of mantle transcriptomes and shell proteomes of gastropods and bivalves are consistent with shell diversity being underpinned by a rapidly evolving mantle secretome (suite of genes expressed in the mantle that encode secreted proteins) that is the product of (a) high rates of gene co-option into and loss from the mantle gene regulatory network, and (b) the rapid evolution of coding sequences, particular those encoding repetitive low complexity domains. Outside a few conserved genes, such as carbonic anhydrase, a so-called "biomineralization toolkit" has yet to be discovered. Despite this, a common suite of protein domains, which are often associated with the extracellular matrix and immunity, appear to have been independently and often uniquely co-opted into the mantle secretomes of different species. The evolvability of the mantle secretome provides a molecular explanation for the evolution and diversity of molluscan shells. These genomic processes are likely to underlie the evolution of other animal biominerals, including coral and echinoderm skeletons. This article is categorized under: Comparative Development and Evolution > Regulation of Organ Diversity Comparative Development and Evolution > Evolutionary Novelties. © 2018 Wiley Periodicals, Inc.

  3. Creep buckling of shell structures

    International Nuclear Information System (INIS)

    Miyazaki, Noriyuki; Hagihara, Seiya

    2015-01-01

    The present article contains a review of the literatures on the creep buckling of shell structures published from late 1950's to recent years. In this article, the creep buckling studies on circular cylindrical shells, spherical shells, partial cylindrical shells and other shells are reviewed in addition to creep buckling criteria. Creep buckling is categorized into two types. One is the creep buckling due to quasi-static instability, in which the critical time for creep buckling is determined by tracing a creep deformation versus time curve. The other is the creep buckling due to kinetic instability, in which the critical time can be determined by examining the shape of total potential energy in the vicinity of a quasi-static equilibrium state. Bifurcation buckling and snap-through buckling during creep deformation belong to this type of creep buckling. A few detailed descriptions are given to the bifurcation and snap-through type of creep buckling based on the present authors' works. (author)

  4. Charged shells in Lovelock gravity: Hamiltonian treatment and physical implications

    International Nuclear Information System (INIS)

    Dias, Goncalo A. S.; Gao, Sijie; Lemos, Jose P. S.

    2007-01-01

    interior, it is proved that the cosmic censorship is definitely upheld. Physical implications of the dynamics of such shells in a large extra dimension world scenario are also drawn. One concludes that, if such a large extra dimension scenario is correct, one can extract enough information from the outcome of those collisions as to know, not only the actual dimension of spacetime, but also which particular Lovelock gravity, general relativity or any other, is the correct one at these scales, in brief, to know d and k

  5. Core-Shell-Corona Micelles with a Responsive Shell.

    Science.gov (United States)

    Gohy, Jean-François; Willet, Nicolas; Varshney, Sunil; Zhang, Jian-Xin; Jérôme, Robert

    2001-09-03

    A reactor for the synthesis of gold nanoparticles is one of the uses of a poly(styrene)-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) triblock copolymer (PS-b-P2VP-b-PEO) which forms core-shell-corona micelles in water. Very low polydispersity spherical micelles are observed that consist of a PS core surrounded by a pH-sensitive P2VP shell and a corona of PEO chains end-capped by a hydroxyl group. The corona can act as a site for attaching responsive or sensing molecules. © 2001 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.

  6. Dominant thermogravimetric signatures of lignin in cashew shell as compared to cashew shell cake.

    Science.gov (United States)

    Gangil, Sandip

    2014-03-01

    Dominant thermogravimetric signatures related to lignin were observed in cashew shell as compared to these signatures in cashew shell cake. The phenomenon of weakening of lignin from cashew shell to cashew shell cake was explained on the basis of changes in the activation energies. The pertinent temperature regimes responsible for the release of different constituents of both the bio-materials were identified and compared. The activation energies of cashew shell and cashew shell cake were compared using Kissinger-Akahira-Sunose method. Thermogravimetric profiling of cashew shell and cashew shell cake indicated that these were different kinds of bio-materials. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Relativistic Bose-Einstein condensates thin-shell wormholes

    Science.gov (United States)

    Richarte, M. G.; Salako, I. G.; Graça, J. P. Morais; Moradpour, H.; Övgün, Ali

    2017-10-01

    We construct traversable thin-shell wormholes which are asymptotically Ads/dS applying the cut and paste procedure for the case of an acoustic metric created by a relativistic Bose-Einstein condensate. We examine several definitions of the flare-out condition along with the violation or not of the energy conditions for such relativistic geometries. Under reasonable assumptions about the equation of state of the matter located at the shell, we concentrate on the mechanical stability of wormholes under radial perturbation preserving the original spherical symmetry. To do so, we consider linearized perturbations around static solutions. We obtain that dS acoustic wormholes remain stable under radial perturbations as long as they have small radius; such wormholes with finite radius do not violate the strong/null energy condition. Besides, we show that stable Ads wormhole satisfy some of the energy conditions whereas unstable Ads wormhole with large radii violate them.

  8. Shell model Monte Carlo methods

    International Nuclear Information System (INIS)

    Koonin, S.E.; Dean, D.J.; Langanke, K.

    1997-01-01

    We review quantum Monte Carlo methods for dealing with large shell model problems. These methods reduce the imaginary-time many-body evolution operator to a coherent superposition of one-body evolutions in fluctuating one-body fields; the resultant path integral is evaluated stochastically. We first discuss the motivation, formalism, and implementation of such Shell Model Monte Carlo (SMMC) methods. There then follows a sampler of results and insights obtained from a number of applications. These include the ground state and thermal properties of pf-shell nuclei, the thermal and rotational behavior of rare-earth and γ-soft nuclei, and the calculation of double beta-decay matrix elements. Finally, prospects for further progress in such calculations are discussed. (orig.)

  9. Cask for concrete shells transportation

    International Nuclear Information System (INIS)

    Labergri, F.

    2001-01-01

    Nowadays, nuclear plant radioactive waste are conditioned in situ into concrete shells. Most of them enter in the industrial waste category defined by the regulations of radioactive material transportation. However, the content of a few ones exceeds the limits set for low specific activity substances. Thus, these shells must be transported into type B packagings. To this end, Robatel has undertaken, for EDF (Electricite de France), the development of a container, named ROBATEL TM R68, for further licensing. The particularity of this packaging is that the lid must have a wide opening to allow the usual handling operations of the concrete shells. This leads to a non-conventional conception, and makes the package more vulnerable to drop test solicitations. In order to define a minimal drop test program on a reduced scale model, we use a simple method to find the most damageable drop angle. (author)

  10. Shell model Monte Carlo methods

    International Nuclear Information System (INIS)

    Koonin, S.E.

    1996-01-01

    We review quantum Monte Carlo methods for dealing with large shell model problems. These methods reduce the imaginary-time many-body evolution operator to a coherent superposition of one-body evolutions in fluctuating one-body fields; resultant path integral is evaluated stochastically. We first discuss the motivation, formalism, and implementation of such Shell Model Monte Carlo methods. There then follows a sampler of results and insights obtained from a number of applications. These include the ground state and thermal properties of pf-shell nuclei, thermal behavior of γ-soft nuclei, and calculation of double beta-decay matrix elements. Finally, prospects for further progress in such calculations are discussed. 87 refs

  11. Evaluation of remaining life of the double-shell tank waste systems

    International Nuclear Information System (INIS)

    Schwenk, E.B.

    1995-01-01

    A remaining life assessment of the DSTs (double-shell tanks) and their associated waste transfer lines, for continued operation over the next 10 years, was favorable. The DST assessment was based on definition of significant loads, evaluation of data for possible material degradation and geometric changes and evaluation of structural analyses. The piping assessment was based primarily on service experience

  12. Evaluation of remaining life of the double-shell tank waste systems

    Energy Technology Data Exchange (ETDEWEB)

    Schwenk, E.B.

    1995-05-04

    A remaining life assessment of the DSTs (double-shell tanks) and their associated waste transfer lines, for continued operation over the next 10 years, was favorable. The DST assessment was based on definition of significant loads, evaluation of data for possible material degradation and geometric changes and evaluation of structural analyses. The piping assessment was based primarily on service experience.

  13. Windows PowerShell 20 Bible

    CERN Document Server

    Lee, Thomas; Schill, Mark E; Tanasovski, Tome

    2011-01-01

    Here's the complete guide to Windows PowerShell 2.0 for administrators and developers Windows PowerShell is Microsoft's next-generation scripting and automation language. This comprehensive volume provides the background that IT administrators and developers need in order to start using PowerShell automation in exciting new ways. It explains what PowerShell is, how to use the language, and specific ways to apply PowerShell in various technologies. Windows PowerShell is Microsoft's standard automation tool and something that every Windows administrator will eventually have to understand; this b

  14. Learning Shell scripting with Zsh

    CERN Document Server

    Festari, Gaston

    2014-01-01

    A step-by-step tutorial that will teach you, through real-world examples, how to configure and use Zsh and its various features. If you are a system administrator, developer, or computer professional involved with UNIX who are looking to improve on their daily tasks involving the UNIX shell, ""Learning Shell Scripting with Zsh"" will be great for you. It's assumed that you have some familiarity with an UNIX command-line interface and feel comfortable with editors such as Emacs or vi.

  15. Goal Definition

    DEFF Research Database (Denmark)

    Bjørn, Anders; Laurent, Alexis; Owsianiak, Mikołaj

    2018-01-01

    The goal definition is the first phase of an LCA and determines the purpose of a study in detail. This chapter teaches how to perform the six aspects of a goal definition: (1) Intended applications of the results, (2) Limitations due to methodological choices, (3) Decision context and reasons...... for carrying out the study, (4) Target audience , (5) Comparative studies to be disclosed to the public and (6) Commissioner of the study and other influential actors. The instructions address both the conduct and reporting of a goal definition and are largely based on the ILCD guidance document (EC...

  16. Isogeometric shell formulation based on a classical shell model

    KAUST Repository

    Niemi, Antti; Collier, Nathan; Dalcí n, Lisandro D.; Ghommem, Mehdi; Calo, Victor M.

    2012-01-01

    The authors future work is concerned with building an isogeometric finite element method for modelling nonlinear structural response of thin-walled shells undergoing large rigid-body motions. The aim is to use the model in a aeroelastic framework for the simulation of flapping wings.

  17. Activated carbons prepared from hazelnut shells, walnut shells and peanut shells for high CO2 adsorption

    Directory of Open Access Journals (Sweden)

    Lewicka Katarzyna

    2017-06-01

    Full Text Available Research treats about producing activated carbons for CO2 capture from hazelnut shells (HN, walnut shells (WN and peanut shells (PN. Saturated solution of KOH was used as an activating agent in ratio 1:1. Samples were carbonized in the furnace in the range of temperatures 600°C–900°C. Properties of carbons were tested by N2 adsorption method, using BET equation, DFT method and volumetric CO2 adsorption method. With the increase of carbonization temperature specific surface area of studied samples increased. The largest surface area was calculated for samples carbonized at 900°C and the highest values of CO2 adsorption had samples: PN900 at 0°C (5.5 mmol/g and WN900 at 25°C (4.34 mmol/g. All of the samples had a well-developed microporous structure.

  18. Scope Definition

    DEFF Research Database (Denmark)

    Bjørn, Anders; Owsianiak, Mikołaj; Laurent, Alexis

    2018-01-01

    The scope definition is the second phase of an LCA. It determines what product systems are to be assessed and how this assessment should take place. This chapter teaches how to perform a scope definition. First, important terminology and key concepts of LCA are introduced. Then, the nine items...... making up a scope definition are elaborately explained: (1) Deliverables. (2) Object of assessment, (3) LCI modelling framework and handling of multifunctional processes, (4) System boundaries and completeness requirements, (5) Representativeness of LCI data, (6) Preparing the basis for the impact...... assessment, (7) Special requirements for system comparisons, (8) Critical review needs and (9) Planning reporting of results. The instructions relate both to the performance and reporting of a scope definition and are largely based on ILCD....

  19. Indentation of Ellipsoidal and Cylindrical Elastic Shells

    KAUST Repository

    Vella, Dominic; Ajdari, Amin; Vaziri, Ashkan; Boudaoud, Arezki

    2012-01-01

    Thin shells are found in nature at scales ranging from viruses to hens' eggs; the stiffness of such shells is essential for their function. We present the results of numerical simulations and theoretical analyses for the indentation of ellipsoidal

  20. Adaptative mixed methods to axisymmetric shells

    International Nuclear Information System (INIS)

    Malta, S.M.C.; Loula, A.F.D.; Garcia, E.L.M.

    1989-09-01

    The mixed Petrov-Galerkin method is applied to axisymmetric shells with uniform and non uniform meshes. Numerical experiments with a cylindrical shell showed a significant improvement in convergence and accuracy with adaptive meshes. (A.C.A.S.) [pt

  1. Tube in shell heat exchangers

    International Nuclear Information System (INIS)

    Hayden, O.; Willby, C.R.; Sheward, G.E.; Ormrod, D.T.; Firth, G.F.

    1980-01-01

    An improved tube-in-shell heat exchanger to be used between liquid metal and water is described for use in the liquid metal coolant system of fast breeder reactors. It is stated that this design is less prone to failures which could result in sodium water reactions than previous exchangers. (UK)

  2. Shell theorem for spontaneous emission

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst; Mortensen, Jakob Egeberg; Lodahl, Peter

    2013-01-01

    and therefore is given exactly by the dipole approximation theory. This surprising result is a spontaneous emission counterpart to the shell theorems of classical mechanics and electrostatics and provides insights into the physics of mesoscopic emitters as well as great simplifications in practical calculations....

  3. Nonlinear theory of elastic shells

    International Nuclear Information System (INIS)

    Costa Junior, J.A.

    1979-08-01

    Nonlinear theory of elastic shells is developed which incorporates both geometric and physical nonlinearities and which does not make use of the well known Love-Kirchhoff hypothesis. The resulting equations are formulated in tensorial notation and are reduced to the ones of common use when simplifying assumptions encountered in the especific litterature are taken. (Author) [pt

  4. Shell energy scenarios to 2050

    International Nuclear Information System (INIS)

    2008-01-01

    Shell developed two scenarios that describe alternative ways the energy future may develop. In the first scenario (Scramble) policymakers pay little attention to more efficient energy use until supplies are tight. Likewise, greenhouse gas emissions are not seriously addressed until there are major climate shocks. In the second scenario (Blueprints) growing local actions begin to address the challenges of economic development, energy security and environmental pollution. A price is applied to a critical mass of emissions giving a huge stimulus to the development of clean energy technologies, such as carbon dioxide capture and storage, and energy efficiency measures. The result is far lower carbon dioxide emissions. Both these scenarios can help Shell to test their strategy against a range of possible developments over the long-term. However, according to Shell, the Blueprints' outcomes offer the best hope for a sustainable future, whether or not they arise exactly in the way described. However, with the right combination of policy, technology and commitment from governments, industry and society globally, Shell believes it can be realized. But achieving the targets will not be easy, and time is short. Clear thinking, huge investment, and effective leadership are required

  5. Collapse analysis of toroidal shell

    International Nuclear Information System (INIS)

    Pomares, R.J.

    1990-01-01

    This paper describes a study performed to determine the collapse characteristics of a toroidal shell using finite element method (FEM) analysis. The study also included free drop testing of a quarter scale prototype to verify the analytical results. The full sized toroidal shell has a 24-inch toroidal diameter with a 24-inch tubal diameter. The shell material is type 304 strainless steel. The toroidal shell is part of the GE Model 2000 transportation packaging, and acts as an energy absorbing device. The analyses performed were on a full sized and quarter scaled models. The finite element program used in all analyses was the LIBRA code. The analytical procedure used both the elasto-plastic and large displacement options within the code. The loading applied in the analyses corresponded to an impact of an infinite rigid plane oriented normal to the drop direction vector. The application of the loading continued incrementally until the work performed by the deforming structure equalled the kinetic energy developed in the free fall. The comparison of analysis and test results showed a good correlation

  6. Studies of dust shells around stars

    International Nuclear Information System (INIS)

    Bedijn, P.J.

    1977-01-01

    This thesis deals with some aspects of circumstellar dust shells. This dust shell, emitting infrared radiation, is described by way of its absorptive and emissive properties as well as by the transfer of radiation through the dust shell itself. Model calculations are compared to experimental results and agree reasonably well. The author also discusses the dynamics of the extended shells of gas and dust around newly formed stars

  7. Thin-shell wormholes in dilaton gravity

    International Nuclear Information System (INIS)

    Eiroa, Ernesto F.; Simeone, Claudio

    2005-01-01

    In this work we construct charged thin-shell Lorentzian wormholes in dilaton gravity. The exotic matter required for the construction is localized in the shell and the energy conditions are satisfied outside the shell. The total amount of exotic matter is calculated and its dependence with the parameters of the model is analyzed

  8. Shell film- and video catalogue 1996

    International Nuclear Information System (INIS)

    1996-01-01

    An overview is given of films and videos that are available through 'Shell Nederland Filmcentrale' (Shell Netherlands Film Center), subdivided into the subjects (1) About Shell; (2) Health, Safety and Environment; (3) Science and Technology; (4) The History of Car(racing); and (5) Historical Overview. 5 ills

  9. A finite element for plates and shells

    International Nuclear Information System (INIS)

    Muller, A.; Feijoo, R.A.; Bevilacqua, L.

    1981-08-01

    A simple triangular finite element for plates and shells, is presented. Since the rotation fields are assumed independent of the displacement fields, the element allows one to solve thick shells problems. In the limit for thin shell, the Kirchoff-Love hypothesis is automatically satisfied, thus enlarging its range of application. (Author) [pt

  10. Vibrations of Thin Piezoelectric Shallow Shells

    Indian Academy of Sciences (India)

    Abstract. In this paper we consider the eigenvalue problem for piezoelectric shallow shells and we show that, as the thickness of the shell goes to zero, the eigensolutions of the three-dimensional piezoelectric shells converge to the eigensolutions of a two-dimensional eigenvalue problem.

  11. Extensions to a nonlinear finite-element axisymmetric shell model based on Reissner's shell theory

    International Nuclear Information System (INIS)

    Cook, W.A.

    1981-01-01

    Extensions to shell analysis not usually associated with shell theory are described in this paper. These extensions involve thick shells, nonlinear materials, a linear normal stress approximation, and a changing shell thickness. A finite element shell-of-revolution model has been developed to analyze nuclear material shipping containers under severe impact conditions. To establish the limits for this shell model, the basic assumptions used in its development were studied; these are listed in this paper. Several extensions were evident from the study of these limits: a thick shell, a plastic hinge, and a linear normal stress

  12. Design aids for stiffened composite shells with cutouts

    CERN Document Server

    Sahoo, Sarmila

    2017-01-01

    This book focuses on the free vibrations of graphite-epoxy laminated composite stiffened shells with cutout both in terms of the natural frequencies and mode shapes. The dynamic analysis of shell structures, which may have complex geometry and arbitrary loading and boundary conditions, is solved efficiently by the finite element method, even including cutouts in shells. The results may be readily used by practicing engineers dealing with stiffened composite shells with cutouts. Several shell forms viz. cylindrical shell, hypar shell, conoidal shell, spherical shell, saddle shell, hyperbolic paraboloidal shell and elliptic paraboloidal shell are considered in the book. The dynamic characteristics of stiffened composite shells with cutout are described in terms of the natural frequency and mode shapes. The size of the cutouts and their positions with respect to the shell centre are varied for different edge constraints of cross-ply and angle-ply laminated composite shells. The effects of these parametric variat...

  13. Pressure Shell Approach to Integrated Environmental Protection

    Science.gov (United States)

    Kennedy, Kriss J.

    2011-01-01

    The next generation of exploration mission human systems will require environmental protection such as radiation protection that is effective and efficient. In order to continue human exploration, habitat systems will require special shells to protect astronauts from hostile environments. The Pressure Shell Approach to integrated environmental (radiation) protection is a multi-layer shell that can be used for multifunctional environmental protection. Self-healing, self-repairing nano technologies and sensors are incorporated into the shell. This shell consists of multiple layers that can be tailored for specific environmental protection needs. Mainly, this innovation focuses on protecting crew from exposure to micrometeorites, thermal, solar flares, and galactic cosmic ray (GCR) radiation. The Pressure Shell Approach consists of a micrometeoroid and secondary ejecta protection layer; a thin, composite shell placed in between two layers that is non-structural; an open cavity layer that can be filled with water, regolith, or polyethylene foam; a thicker composite shell that is a structural load bearing that is placed between two layers; and a bladder coating on the interior composite shell. This multi-layer shell creates an effective radiation protection system. Most of its layers can be designed with the materials necessary for specific environments. In situ materials such as water or regolith can be added to the shell design for supplemental radiation protection.

  14. Indentation of Ellipsoidal and Cylindrical Elastic Shells

    KAUST Repository

    Vella, Dominic

    2012-10-01

    Thin shells are found in nature at scales ranging from viruses to hens\\' eggs; the stiffness of such shells is essential for their function. We present the results of numerical simulations and theoretical analyses for the indentation of ellipsoidal and cylindrical elastic shells, considering both pressurized and unpressurized shells. We provide a theoretical foundation for the experimental findings of Lazarus etal. [following paper, Phys. Rev. Lett. 109, 144301 (2012)PRLTAO0031-9007] and for previous work inferring the turgor pressure of bacteria from measurements of their indentation stiffness; we also identify a new regime at large indentation. We show that the indentation stiffness of convex shells is dominated by either the mean or Gaussian curvature of the shell depending on the pressurization and indentation depth. Our results reveal how geometry rules the rigidity of shells. © 2012 American Physical Society.

  15. Double containment shell for nuclear power plants

    International Nuclear Information System (INIS)

    Sykora, D.

    1977-01-01

    A double containment shell is proposed for nuclear power plants, especially those equipped with pressurized water reactors. The shell offers increased environmental protection from primary circuit accidents. The inner shell is built of steel or concrete while the outer shell is always built of concrete. The space between the two shells is filled with water and is provided with several manholes and with stiffeners designed for compensation for load due to the water hydrostatic pressure. Water serves the airtight separation of the containment shell inside from the environment and the absorption of heat released in a primary circuit accident. In case the inner shell is made of concrete, it is provided with heat-removal tubes in-built in its walls ensuring rapid heat transfer from the inside of the containment to the water in the interwall space. (Z.M.)

  16. Recent developments in anisotropic heterogeneous shell theory

    CERN Document Server

    Grigorenko, Alexander Ya; Grigorenko, Yaroslav M; Vlaikov, Georgii G

    2016-01-01

    This volume focuses on the relevant general theory and presents some first applications, namely those based on classical shell theory. After a brief introduction, during which the history and state-of-the-art are discussed, the first chapter presents the mechanics of anisotropic heterogeneous shells, covering all relevant assumptions and the basic relations of 3D elasticity, classical and refined shell models. The second chapter examines the numerical techniques that are used, namely discrete orthogonalization, spline-collocation and Fourier series, while the third highlights applications based on classical theory, in particular, the stress-strain state of shallow shells, non-circular shells, shells of revolution, and free vibrations of conical shells. The book concludes with a summary and an outlook bridging the gap to the second volume.

  17. Atomic inner-shell physics

    International Nuclear Information System (INIS)

    Crasemann, B.

    1985-01-01

    This book discusses: relativistic and quantum electrodynamic effects on atomic inner shells; relativistic calculation of atomic transition probabilities; many-body effects in energetic atomic transitions; Auger Electron spectrometry of core levels of atoms; experimental evaluation of inner-vacancy level energies for comparison with theory; mechanisms for energy shifts of atomic K-X rays; atomic physics research with synchrotron radiation; investigations of inner-shell states by the electron energy-loss technique at high resolution; coherence effects in electron emission by atoms; inelastic X-ray scattering including resonance phenomena; Rayleigh scattering: elastic photon scattering by bound electrons; electron-atom bremsstrahlung; X-ray and bremsstrahlung production in nuclear reactions; positron production in heavy-ion collisions, and X-ray processes in heavy-ion collisions

  18. Slow pyrolysis of pistachio shell

    Energy Technology Data Exchange (ETDEWEB)

    Apaydin-Varol, Esin; Putun, Ersan; Putun, Ayse E [Anadolu University, Eskisehir (Turkey). Department of Chemical Engineering

    2007-08-15

    In this study, pistachio shell is taken as the biomass sample to investigate the effects of pyrolysis temperature on the product yields and composition when slow pyrolysis is applied in a fixed-bed reactor at atmospheric pressure to the temperatures of 300, 400, 500, 550, 700{sup o}C. The maximum liquid yield was attained at about 500-550{sup o}C with a yield of 20.5%. The liquid product obtained under this optimum temperature and solid products obtained at all temperatures were characterized. As well as proximate and elemental analysis for the products were the basic steps for characterization, column chromatography, FT-IR, GC/MS and SEM were used for further characterization. The results showed that liquid and solid products from pistachio shells show similarities with high value conventional fuels. 31 refs., 9 figs., 1 tab.

  19. Shell trips over its reserves

    International Nuclear Information System (INIS)

    Jemain, A.

    2004-01-01

    Some mistakes in the evaluation of the proven reserves of Royal Dutch Shell group, the second world petroleum leader, will oblige the other oil and gas companies to be more transparent and vigilant in the future. The proven reserves ('P90' in petroleum professionals' language) are the most important indicators of the mining patrimony of companies. These strategic data are reported each year in the annual reports of the companies and are examined by the security exchange commission. The evaluation of reserves is perfectly codified by the US energy policy and conservation act and its accountable translation using the FAS 69 standard allows to establish long-term cash-flow forecasts. The revision announced by Shell on January 9 leads to a 20% reduction of its proven reserves. Short paper. (J.S.)

  20. Læren fra Shell

    DEFF Research Database (Denmark)

    Ørding Olsen, Anders

    2017-01-01

    Hvad kan afsløringerne om Shells mere end 25 år gamle viden om klimaforandringer lære virksomheder om disruption og strategi? Først og fremmest at undgå at se disruption som en mulig trussel, men i stedet som en fremtidig realitet og chance for vækst......Hvad kan afsløringerne om Shells mere end 25 år gamle viden om klimaforandringer lære virksomheder om disruption og strategi? Først og fremmest at undgå at se disruption som en mulig trussel, men i stedet som en fremtidig realitet og chance for vækst...

  1. The shell coal gasification process

    Energy Technology Data Exchange (ETDEWEB)

    Koenders, L.O.M.; Zuideveld, P.O. [Shell Internationale Petroleum Maatschappij B.V., The Hague (Netherlands)

    1995-12-01

    Future Integrated Coal Gasification Combined Cycle (ICGCC) power plants will have superior environmental performance and efficiency. The Shell Coal Gasification Process (SCGP) is a clean coal technology, which can convert a wide range of coals into clean syngas for high efficiency electricity generation in an ICGCC plant. SCGP flexibility has been demonstrated for high-rank bituminous coals to low rank lignites and petroleum coke, and the process is well suited for combined cycle power generation, resulting in efficiencies of 42 to 46% (LHV), depending on choice of coal and gas turbine efficiency. In the Netherlands, a 250 MWe coal gasification combined cycle plant based on Shell technology has been built by Demkolec, a development partnership of the Dutch Electricity Generating Board (N.V. Sep). The construction of the unit was completed end 1993 and is now followed by start-up and a 3 year demonstration period, after that the plant will be part of the Dutch electricity generating system.

  2. Nested shell superconducting magnet designs

    International Nuclear Information System (INIS)

    Bromberg, L.; Williams, J.E.C.; Titus, P.

    1992-01-01

    A new concept for manufacturing the toroidal field coil is described in this paper. Instead of structural plates, the magnet is wound in interlocking shells. The magnet configuration is described and the advantages explored. Structural analysis of the concept is performed using the ARIES tokamak reactor parameters. The effectiveness of a structural cap, placed above and below the toroidal field coils and used only to balance opposing torques generated in different places of the coil, is quantified

  3. Shell Models of Superfluid Turbulence

    International Nuclear Information System (INIS)

    Wacks, Daniel H; Barenghi, Carlo F

    2011-01-01

    Superfluid helium consists of two inter-penetrating fluids, a viscous normal fluid and an inviscid superfluid, coupled by a mutual friction. We develop a two-fluid shell model to study superfluid turbulence and investigate the energy spectra and the balance of fluxes between the two fluids in a steady state. At sufficiently low temperatures a 'bottle-neck' develops at high wavenumbers suggesting the need for a further dissipative effect, such as the Kelvin wave cascade.

  4. Plastic buckling of cylindrical shells

    International Nuclear Information System (INIS)

    Bandyopadhyay, K.; Xu, J.; Shteyngart, S.; Eckert, H.

    1994-01-01

    Cylindrical shells exhibit buckling under axial loads at stresses much less than the respective theoretical critical stresses. This is due primarily to the presence of geometrical imperfections even though such imperfections could be very small (e.g., comparable to thickness). Under internal pressure, the shell regains some of its buckling strength. For a relatively large radius-to-thickness ratio and low internal pressure, the effect can be reasonably estimated by an elastic analysis. However, for low radius-to-thickness ratios and greater pressures, the elastic-plastic collapse controls the failure load. in order to quantify the elastic-plastic buckling capacity of cylindrical shells, an analysis program was carried out by use of the computer code BOSOR5 developed by Bushnell of Lockheed Missiles and Space Company. The analysis was performed for various radius-to-thickness ratios and imperfection amplitudes. The purpose of the analytical program was to compute the buckling strength of underground cylindrical tanks, that are used for storage of nuclear wastes, for realistic geometric imperfections and internal pressure loads. This paper presents the results of the elastic-plastic analyses and compares them with other available information for various pressure loads

  5. Buckling shells are also swimmers

    Science.gov (United States)

    Quilliet, Catherine; Dyfcom Bubbleboost Team

    We present an experimental and numerical study on the displacement of shells undergoing deformations in a fluid. When submitted to cycles of pressure difference between outside and inside, a shell buckles and debuckles, showing a succession of shapes and a dynamics that are different during the two phases. Hence such objects are likely to swim, including at low Reynolds (microscopic scale). We studied the swimming of buckling/debuckling shells at macroscopic scale using different approaches (force quantization, shape recording, displacement along a frictionless rail, study of external flow using PIV), and showed that inertia plays a role in propulsion, even in situations where dimensionless numbers correspond also to microswimmers in water. Different fluid viscosities were explored, showing an optimum for the displacement. Interestingly, the most favorable cases lead to displacements in the same direction and sense during both motor stroke (buckling phase) and recovery stroke (de-buckling phase). This work opens the route for the synthesis with high throughput of abusively simple synthetic swimmers, possibly gathered into nanorobots, actuated by a scalar field such as the pressure in echographic devices. Universite Grenoble Alpes, CNRS, European Research Council.

  6. The Mg - SST relationship in mollusc shells: is there a rule? Examples from three tropical species

    Science.gov (United States)

    Lazareth, C. E.; Guzmán, N.; Lecornec, F.; Cabioch, G.; Ortlieb, L.

    2009-04-01

    The geochemistry of mollusc shells is currently viewed as a powerful tool for paleoenvironmental reconstructions. Indeed, molluscs are ubiquitous animals, with a worldly geographical and environmental distribution, providing various environmental records. Moreover, mollusc shells are abundantly found in fossil and archaeological settings. In the paleoclimatic reconstructions, the sea-surface temperatures (SST) are a key parameter. If shell stable oxygen isotope signatures can provide accurate SST records, this proxy is also influenced by the water isotopic composition. To find another tracer which would depend on the SST solely, the relationship between Mg content changes in mollusc shell and SST has been investigated for a few years. Nevertheless, if the reliability of shell Mg as SST tracer has been proven in some species, this is clearly not a "universal" and definitive rule. To reconstruct the past tropical SSTs, Mg calibration studies were undertaken on Concholepas concholepas (gastropod, South America), Protothaca thaca (bivalve, South America) and Tridacna squamosa (bivalve, New Caledonia). The very high-resolution (infra-daily) analyses of the C. concholepas gastropod revealed a significant metabolism control, at the nyctemeral scale, on the Mg incorporation into the calcite shell layer. Over a two months period, the Mg fluctuations in C. concholepas shell do not match with the SST instrumental measurements. Mg content changes along the aragonitic shell growth axis of several living P. thaca from a same Peruvian site are significantly different indicating no relationship between Mg and SST. The Mg variations measured in a Chilean P. thaca shell are, surprisingly, similar to variations of the instrumental SST. Unless this quite reliable relationship between P. thaca shell and SST is confirmed, and that the inter-site difference in Mg response to environmental forcing is understood, P. thaca shell Mg cannot be used as SST proxy. Lastly, a preliminary work

  7. Mussel Shell Impaction in the Esophagus

    Directory of Open Access Journals (Sweden)

    Sunmin Kim

    2013-03-01

    Full Text Available Mussels are commonly used in cooking around the world. The mussel shell breaks more easily than other shells, and the edge of the broken mussel shell is sharp. Impaction can ultimately cause erosion, perforation and fistula. Aside from these complications, the pain can be very intense. Therefore, it is essential to verify and remove the shell as soon as possible. In this report we describe the process of diagnosing and treating mussel shell impaction in the esophagus. Physicians can overlook this unusual foreign body impaction due to lack of experience. When physicians encounter a patient with severe chest pain after a meal with mussels, mussel shell impaction should be considered when diagnosing and treating the patient.

  8. Vibration of liquid-filled thin shells

    International Nuclear Information System (INIS)

    Kalnins, A.

    1979-01-01

    This paper describes the analysis of free and forced vibration of a thin, axisymmetric shell, which contains some liquid. The axis of symmetry is vertical. Only such vibration is considered which can be produced by a horizontal movement of the base of shell. The objective of this paper is to examine the response of the coupled shell-liquid system for a frequency range lying between zero and the lowest natural sloshing frequency of the liquid. The mass of the liquid is modeled by a stationary and one or more sloshing masses. It is shown how the stationary mass can be incorporated in the vibration analysis of the shell and how to natural frequency of the coupled shell-liquid system can be obtained from a simple formula, if the lowest natural frequency of the shell, plus the stationary mass of the liquid, can be determined. A numerical example is given. (orig.)

  9. Ancient shell industry at Bet Dwarka island

    Digital Repository Service at National Institute of Oceanography (India)

    Gaur, A.S.; Sundaresh; Patankar, V.

    for the manufacture of beads, bangles, etc. 12 . Shell species found at the sites include T. pyrum (cha nk), Chicoreus ramosus , Fasciolaria trapezium , Cypraea (cowries), Arabica arabica (cowries), Babylonia spirata , dentalium, mussel and Arca... muscles are attached. Average length of a shell can be up to 15 to 20 cm and width 10 ? 15 cm 8 . It provides a unique structure for the manufacture of several bangles from a single shell. The organ ism living inside is also edible...

  10. Integrable structure in discrete shell membrane theory.

    Science.gov (United States)

    Schief, W K

    2014-05-08

    We present natural discrete analogues of two integrable classes of shell membranes. By construction, these discrete shell membranes are in equilibrium with respect to suitably chosen internal stresses and external forces. The integrability of the underlying equilibrium equations is proved by relating the geometry of the discrete shell membranes to discrete O surface theory. We establish connections with generalized barycentric coordinates and nine-point centres and identify a discrete version of the classical Gauss equation of surface theory.

  11. Local shell-to-shell energy transfer via nonlocal interactions in fluid ...

    Indian Academy of Sciences (India)

    However, the shell-to-shell energy transfer rate is found to be local and forward. .... interaction was strong, but the energy exchange occurred predominantly between ..... The wave-number range considered is in the inverse cascade regime.

  12. Statistics and the shell model

    International Nuclear Information System (INIS)

    Weidenmueller, H.A.

    1985-01-01

    Starting with N. Bohr's paper on compound-nucleus reactions, we confront regular dynamical features and chaotic motion in nuclei. The shell-model and, more generally, mean-field theories describe average nuclear properties which are thus identified as regular features. The fluctuations about the average show chaotic behaviour of the same type as found in classical chaotic systems upon quantisation. These features are therefore generic and quite independent of the specific dynamics of the nucleus. A novel method to calculate fluctuations is discussed, and the results of this method are described. (orig.)

  13. Electron Shell as a Resonator

    International Nuclear Information System (INIS)

    Karpeshin, F. F.

    2002-01-01

    Main principles of the resonance effect arising in the electron shells in interaction of the nuclei with electromagnetic radiation are analyzed and presented in the historical aspect. Principles of NEET are considered from a more general position, as compared to how this is usually presented. Characteristic features of NEET and its reverse, TEEN, as internal conversion processes are analyzed, and ways are offered of inducing them by laser radiation. The ambivalent role of the Pauli exclusion principles in NEET and TEEN processes is investigated.

  14. Carbon isotopes in mollusk shell carbonates

    Science.gov (United States)

    McConnaughey, Ted A.; Gillikin, David Paul

    2008-10-01

    Mollusk shells contain many isotopic clues about calcification physiology and environmental conditions at the time of shell formation. In this review, we use both published and unpublished data to discuss carbon isotopes in both bivalve and gastropod shell carbonates. Land snails construct their shells mainly from respired CO2, and shell δ13C reflects the local mix of C3 and C4 plants consumed. Shell δ13C is typically >10‰ heavier than diet, probably because respiratory gas exchange discards CO2, and retains the isotopically heavier HCO3 -. Respired CO2 contributes less to the shells of aquatic mollusks, because CO2/O2 ratios are usually higher in water than in air, leading to more replacement of respired CO2 by environmental CO2. Fluid exchange with the environment also brings additional dissolved inorganic carbon (DIC) into the calcification site. Shell δ13C is typically a few ‰ lower than ambient DIC, and often decreases with age. Shell δ13C retains clues about processes such as ecosystem metabolism and estuarine mixing. Ca2+ ATPase-based models of calcification physiology developed for corals and algae likely apply to mollusks, too, but lower pH and carbonic anhydrase at the calcification site probably suppress kinetic isotope effects. Carbon isotopes in biogenic carbonates are clearly complex, but cautious interpretation can provide a wealth of information, especially after vital effects are better understood.

  15. Electrochemical characterization of supercapacitors based on carbons derived from coffee shells

    Energy Technology Data Exchange (ETDEWEB)

    Jisha, M.R.; Hwang, Yun Ju [Department of Hydrogen and Fuel cells Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Shin, Jae Sun [School of Nanosemiconductor display, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Nahm, Kee Suk [Department of Hydrogen and Fuel cells Engineering, Chonbuk National University and School of Chemical Engineering and Technology, Jeonju 561-756 (Korea, Republic of)], E-mail: nahmks@chonbuk.ac.kr; Prem Kumar, T.; Karthikeyan, K.; Dhanikaivelu, N.; Kalpana, D.; Renganathan, N.G.; Stephan, A. Manuel [Central Electro Chemical Research Institute, Karaikudi 630006 (India)

    2009-05-15

    Carbons derived by pyrolysis of coffee shells treated with ZnCl{sub 2} were used as electrode materials in symmetric electrochemical supercapacitors. Scanning electron microscopy showed that the carbon from the porogen-free shells show a flake-like structure, while those from the ZnCl{sub 2}-treated coffee shells have a loose, disjointed structure with no definite shape. X-ray diffraction studies indicated the presence of small domains of coherent and parallel stacking of the graphene sheets. The average surface area of the carbon was 842 m{sup 2} g{sup -1}, with an average micropore area of 400 m{sup 2} g{sup -1}. Cyclic voltammetric studies suggested a specific capacitance of about 150 F g{sup -1}. Self-discharge studies on the devices showed a large retention time.

  16. Development and application of General Purpose Data Acquisition Shell (GPDAS) at advanced photon source

    International Nuclear Information System (INIS)

    Chung, Youngjoo; Kim, Keeman.

    1991-01-01

    An operating system shell GPDAS (General Purpose Data Acquisition Shell) on MS-DOS-based microcomputers has been developed to provide flexibility in data acquisition and device control for magnet measurements at the Advanced Photon Source. GPDAS is both a command interpreter and an integrated script-based programming environment. It also incorporates the MS-DOS shell to make use of the existing utility programs for file manipulation and data analysis. Features include: alias definition, virtual memory, windows, graphics, data and procedure backup, background operation, script programming language, and script level debugging. Data acquisition system devices can be controlled through IEEE488 board, multifunction I/O board, digital I/O board and Gespac crate via Euro G-64 bus. GPDAS is now being used for diagnostics R ampersand D and accelerator physics studies as well as for magnet measurements. Their hardware configurations will also be discussed. 3 refs., 3 figs

  17. Characterization of pecan nut expeller cake and effect of storage on its microbiological and oxidative quality; Caracterización de la torta prensada de nuez de pecan y efecto del almacenamiento sobre su calidad microbiológica y oxidativa

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, L.; Romero, L.; Andrés, S.C.; Califano, A.N.

    2017-07-01

    Pecan nut expeller cake (PNEC), a by-product of pecan oil extraction, was characterized and the effect of packaging and storage conditions was investigated. Samples were packaged under vacuum or in normal atmosphere and stored (10 or 20 ºC) for 12 months. Its composition, water and oil absorption, fatty acids profile, lipid oxidation (thiobarbituric acid reactive substances, TBARS), antioxidant activity [Diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl] radical, DPPH● and [(2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)] radical cation, ABTS●+), and microbiological quality were analyzed. PNEC showed high lipid and fiber contents (51.4 and 21.6 g/100g, respectively) with good water and oil absorption capacity. Vacuum storage at 10 ºC preserved antioxidant capacity (TBARS: malondialdehyde= 0.23 mg/kg, IC50 DPPH = 9.0 mg/mL, and IC50 ABTS = 21 mg/mL after one year storage). Extremely low mold and yeast levels were found in PNEC in low permeability vacuum packages, regardless of the storage temperature. Thus, PNEC could retain suitable quality attributes for up to 12 months using the right combination of packaging and temperature. [Spanish] La torta de prensada de nuez de pecan (PNEC), un sub-producto dela extracción de aceite de pecan, fue caracterizado y se investigó el efecto del embalaje y condiciones de almacenamiento. Las muestras fueron envasadas con y sin vacío y almacenadas (10 o 20ºC) durante 12 meses. Se analizó la composición, absorción de agua y aceite, perfiles de ácidos grasos, oxidación lipídica (sustancias reactivas al ácido tiobarbitúrico, TBARS), actividad antioxidante [radical (difenil-1-(2,4,6-trinitrofenil) hidracilo] DPPH● y catión radical [ácido (2,2′-azinobis-(3-etilbenzotiazolin-6-sulfónico)], ABTS●+) y calidad microbiológica. El PNEC mostró altos contenidos de lípidos y fibra (51.4 y 21.6 g/100g, respectivamente) con buenas capacidades de absorción de agua y aceite. El almacenamiento bajo vacío a 10º

  18. A design chart for long vacuum pipes and shells

    International Nuclear Information System (INIS)

    Krempetz, K.; Grimson, J.; Kelly, P.

    1986-01-01

    This paper presents a design chart to aid designers in the selection of a wall thickness for long cylindrical shells having atmospheric pressure outside the shell and a pressure less than atmospheric inside the shell. The chart indicates a conservative value for the minimum wall thickness for a given shell diameter and material when the shell is completely evacuated

  19. Composted oyster shell as lime fertilizer is more effective than fresh oyster shell.

    Science.gov (United States)

    Lee, Young Han; Islam, Shah Md Asraful; Hong, Sun Joo; Cho, Kye Man; Math, Renukaradhya K; Heo, Jae Young; Kim, Hoon; Yun, Han Dae

    2010-01-01

    Physio-chemical changes in oyster shell were examined, and fresh and composted oyster shell meals were compared as lime fertilizers in soybean cultivation. Structural changes in oyster shell were observed by AFM and FE-SEM. We found that grains of the oyster shell surface became smoother and smaller over time. FT-IR analysis indicated the degradation of a chitin-like compound of oyster shell. In chemical analysis, pH (12.3+/-0.24), electrical conductivity (4.1+/-0.24 dS m(-1)), and alkaline powder (53.3+/-1.12%) were highest in commercial lime. Besides, pH was higher in composted oyster shell meal (9.9+/-0.53) than in fresh oyster shell meal (8.4+/-0.32). The highest organic matter (1.1+/-0.08%), NaCl (0.54+/-0.03%), and moisture (15.1+/-1.95%) contents were found in fresh oyster shell meal. A significant higher yield of soybean (1.33 t ha(-1)) was obtained by applying composted oyster shell meal (a 21% higher yield than with fresh oyster shell meal). Thus composting of oyster shell increases the utility of oyster shell as a liming material for crop cultivation.

  20. Transitional nuclei near shell closures

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, G. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064 (India); Pai, H. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064, India and Present Address: Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstrasse 9, 64289 Darmstadt (Germany)

    2014-08-14

    High spin states in Bismuth and Thallium nuclei near the Z = 82 shell closure and Cesium nuclei near the N = 82 shell closure in A = 190 and A = 130 regions, respectively, have been experimentally investigated using heavy-ion fusion evaporation reaction and by detecting the gamma rays using the Indian National Gamma Array (INGA). Interesting shape properties in these transitional nuclei have been observed. The results were compared with the neighboring nuclei in these two regions. The total Routhian surface (TRS) calculations have been performed for a better understanding of the observed properties. In mass region A = 190, a change in shape from spherical to deformed has been observd around neutron number N = 112 for the Bi (Z = 83) isotopes with proton number above the magic gap Z = 82, whereas, the shape of Tl (Z = 81) isotopes with proton number below the magic gap Z = 82 remains stable as a function of neutron number. An important transition from aplanar to planar configuration of angular momentum vectors leading to the occurance of nuclar chirality and magnetic rotation, respectively, has been proposed for the unique parity πh{sub 11/2}⊗νh{sub 11/2} configuration in Cs isotopes in the mass region A ∼ 130 around neutron number N = 79. These results are in commensurate with the TRS calculations.

  1. Evolution of shell gaps with neutron richness

    International Nuclear Information System (INIS)

    Basu, Moumita Ray; Ray, I.; Kshetri, Ritesh; Saha Sarkar, M.; Sarkar, S.

    2006-01-01

    In the present work, an attempt has been made to coordinate the recent data available over the periodic table, specially near the shell gaps and studied the evolution of the shell gaps as function of neutron numbers and/or other related quantities

  2. Microsoft Exchange Server PowerShell cookbook

    CERN Document Server

    Andersson, Jonas

    2015-01-01

    This book is for messaging professionals who want to build real-world scripts with Windows PowerShell 5 and the Exchange Management Shell. If you are a network or systems administrator responsible for managing and maintaining Exchange Server 2013, you will find this highly useful.

  3. Shell effects in the nuclear deformation energy

    International Nuclear Information System (INIS)

    Ross, C.K.

    1973-01-01

    A new approach to shell effects in the Strutinsky method for calculating nuclear deformation energy is evaluated and the suggestion of non-conservation of angular momentum in the same method is resolved. Shell effects on the deformation energy in rotational bands of deformed nuclei are discussed. (B.F.G.)

  4. Intershell correlations in photoionization of outer shells

    Energy Technology Data Exchange (ETDEWEB)

    Amusia, M.Ya. [The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel); A.F. Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation); Chernysheva, L.V. [A.F. Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation); Drukarev, E.G. [National Research Center “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute, St. Petersburg 188300 (Russian Federation)

    2016-02-15

    We demonstrate that the cross sections for photoionization of the outer shells are noticeably modified at the photon energies close to the thresholds of ionization of the inner shells due to correlations with the latter. The correlations may lead to increase or to decrease of the cross sections just above the ionization thresholds.

  5. Strength Calculation of Locally Loaded Orthotropic Shells

    Directory of Open Access Journals (Sweden)

    Yu. I. Vinogradov

    2015-01-01

    Full Text Available The article studies laminated orthotropic cylindrical, conic, spherical, and toroidal shells, which are often locally loaded in the aircraft designs over small areas of their surfaces.The aim of this work is to determine stress concentration in shells versus structure of orthotropic composite material, shell form and parameters, forms of loading areas, which borders do not coincide with lines of main curvatures of shells. For this purpose, an analytical computing algorithm to estimate strength of shells in terms of stress is developed. It enables us to have solution results of the boundary value problem with a controlled error. To solve differential equations an analytical method is used. An algorithm of the boundary value problem solution is multiplicative.The main results of researches are graphs of stress concentration in the orthotropic shells versus their parameters and areas of loading lineated by circles and ellipses.Among the other works aimed at determination of stress concentration in shells, the place of this one is defined by the analytical solution of applied problems for strength estimation in terms of shell stresses of classical forms.The developed effective analytical algorithm to solve the boundary value problem and received results are useful in research and development.

  6. Radiometric measuring method for egg shells

    Energy Technology Data Exchange (ETDEWEB)

    Forberg, S; Svaerdstroem, K

    1973-02-01

    A description is given of a fast nondestructive radiometric method for registration of the thickness of egg shells of the tawny owl, hen, osprey, and Canada goose. Certain errors are discussed. Measurement of the thickness of egg shells (mineral content per cm/sup 2/) with an accuracy better than 1% is possible in less than one minute under field conditions. (auth)

  7. Statistical Mechanics of Thin Spherical Shells

    Directory of Open Access Journals (Sweden)

    Andrej Košmrlj

    2017-01-01

    Full Text Available We explore how thermal fluctuations affect the mechanics of thin amorphous spherical shells. In flat membranes with a shear modulus, thermal fluctuations increase the bending rigidity and reduce the in-plane elastic moduli in a scale-dependent fashion. This is still true for spherical shells. However, the additional coupling between the shell curvature, the local in-plane stretching modes, and the local out-of-plane undulations leads to novel phenomena. In spherical shells, thermal fluctuations produce a radius-dependent negative effective surface tension, equivalent to applying an inward external pressure. By adapting renormalization group calculations to allow for a spherical background curvature, we show that while small spherical shells are stable, sufficiently large shells are crushed by this thermally generated “pressure.” Such shells can be stabilized by an outward osmotic pressure, but the effective shell size grows nonlinearly with increasing outward pressure, with the same universal power-law exponent that characterizes the response of fluctuating flat membranes to a uniform tension.

  8. Thick-shell nanocrystal quantum dots

    Science.gov (United States)

    Hollingsworth, Jennifer A [Los Alamos, NM; Chen, Yongfen [Eugene, OR; Klimov, Victor I [Los Alamos, NM; Htoon, Han [Los Alamos, NM; Vela, Javier [Los Alamos, NM

    2011-05-03

    Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm and an outer shell, where said outer shell comprises multiple monolayers, wherein at least 30% of the quantum dots have an on-time fraction of 0.80 or greater under continuous excitation conditions for a period of time of at least 10 minutes.

  9. Fabrication of Foam Shells for ICF Experiments

    Science.gov (United States)

    Czechowicz, D. G.; Acenas, O.; Flowers, J. S.; Nikroo, A.; Paguio, R. R.; Schroen, D. G.; Streit, J.; Takagi, M.

    2004-11-01

    The General Atomics/Schafer team has developed processes to fabricate foam shells targets suitable for ICF experiments. The two most common chemical systems used to produce foam shells have been resorcinol-formaldehyde (R/F) aerogel and divinylbenzene (DVB). Spherical targets have been made in the form of shells and beads having diameters ranging from approximately 0.5 mm to 4.0 mm, and having densities from approximately 100 mg/cc to 250 mg/cc. The work on R/F foam shells has been concentrated on 1) shell fabrication process improvement to obtain high yields ( ˜25%) and 2) depositing a reliable permeation barrier to provide shells for ongoing direct drive experiments at LLE. Development of divinylbenzene foam shells has been mainly directed towards Inertial Fusion Energy applications (at densities as low as 30 mg/cc) and recently for shells for experiments at LLE. Details of the relevant metrology and properties of these foams as well as the range of targets currently available will be discussed.

  10. Intershell correlations in photoionization of outer shells

    International Nuclear Information System (INIS)

    Amusia, M.Ya.; Chernysheva, L.V.; Drukarev, E.G.

    2016-01-01

    We demonstrate that the cross sections for photoionization of the outer shells are noticeably modified at the photon energies close to the thresholds of ionization of the inner shells due to correlations with the latter. The correlations may lead to increase or to decrease of the cross sections just above the ionization thresholds.

  11. Statistical mechanics of microscopically thin thermalized shells

    Science.gov (United States)

    Kosmrlj, Andrej

    Recent explosion in fabrication of microscopically thin free standing structures made from graphene and other two-dimensional materials has led to a renewed interest in the mechanics of such structures in presence of thermal fluctuations. Since late 1980s it has been known that for flat solid sheets thermal fluctuations effectively increase the bending rigidity and reduce the bulk and shear moduli in a scale-dependent fashion. However, much is still unknown about the mechanics of thermalized flat sheets of complex geometries and about the mechanics of thermalized shells with non-zero background curvature. In this talk I will present recent development in the mechanics of thermalized ribbons, spherical shells and cylindrical tubes. Long ribbons are found to behave like hybrids between flat sheets with renormalized elastic constants and semi-flexible polymers, and these results can be used to predict the mechanics of graphene kirigami structures. Contrary to the anticipated behavior for ribbons, the non-zero background curvature of shells leads to remarkable novel phenomena. In shells, thermal fluctuations effectively generate negative surface tension, which can significantly reduce the critical buckling pressure for spherical shells and the critical axial load for cylindrical tubes. For large shells this thermally generated load becomes big enough to spontaneously crush spherical shells and cylindrical tubes even in the absence of external loads. I will comment on the relevance for crushing of microscopic shells (viral capsids, bacteria, microcapsules) due to osmotic shocks and for crushing of nanotubes.

  12. Biomineral repair of abalone shell apertures.

    Science.gov (United States)

    Cusack, Maggie; Guo, Dujiao; Chung, Peter; Kamenos, Nicholas A

    2013-08-01

    The shell of the gastropod mollusc, abalone, is comprised of nacre with an outer prismatic layer that is composed of either calcite or aragonite or both, depending on the species. A striking characteristic of the abalone shell is the row of apertures along the dorsal margin. As the organism and shell grow, new apertures are formed and the preceding ones are filled in. Detailed investigations, using electron backscatter diffraction, of the infill in three species of abalone: Haliotis asinina, Haliotis gigantea and Haliotis rufescens reveals that, like the shell, the infill is composed mainly of nacre with an outer prismatic layer. The infill prismatic layer has identical mineralogy as the original shell prismatic layer. In H. asinina and H. gigantea, the prismatic layer of the shell and infill are made of aragonite while in H. rufescens both are composed of calcite. Abalone builds the infill material with the same high level of biological control, replicating the structure, mineralogy and crystallographic orientation as for the shell. The infill of abalone apertures presents us with insight into what is, effectively, shell repair. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Obtainment of calcium carbonate from mussels shell

    International Nuclear Information System (INIS)

    Hamester, M.R.R.; Becker, D.

    2010-01-01

    The mussels and oyster shell are discarded at environment, and this accumulation is causing negative consequences to ecosystem. Calcium carbonate is main constituent of the shell chemical composition. Aiming to reduce environmental aggression and generate income to shellfish producer, there was the possibility of using these shells as an alternative to commercial calcium carbonate. For this physics, chemicals and thermal properties were evaluated, using X-ray fluorescence, thermogravimetric analysis, size distribution, abrasiveness and scanning electronic microscopy. The results indicate that mussels shells have an initial degradation temperature higher than commercial calcium carbonate e same lost weight behavior and 95% of shell chemical composition is calcium carbonate. The sample size distribution was influenced by grinding condition and time as well as its abrasiveness. (author)

  14. Structural shell analysis understanding and application

    CERN Document Server

    Blaauwendraad, Johan

    2014-01-01

    The mathematical description of the properties of a shell is much more elaborate than those of beam and plate structures. Therefore many engineers and architects are unacquainted with aspects of shell behaviour and design, and are not familiar with sufficiently reliable shell theories for the different shell types as derived in the middle of the 20th century. Rather than contributing to theory development, this university textbook focuses on architectural and civil engineering schools. Of course, practising professionals will profit from it as well. The book deals with thin elastic shells, in particular with cylindrical, conical and spherical types, and with elliptic and hyperbolic paraboloids. The focus is on roofs, chimneys, pressure vessels and storage tanks. Special attention is paid to edge bending disturbance zones, which is indispensable knowledge in FE meshing. A substantial part of the book results from research efforts in the mid 20th century at Delft University of Technology. As such, it is a valua...

  15. Semiclassical shell structure in rotating Fermi systems

    International Nuclear Information System (INIS)

    Magner, A. G.; Sitdikov, A. S.; Khamzin, A. A.; Bartel, J.

    2010-01-01

    The collective moment of inertia is derived analytically within the cranking model for any rotational frequency of the harmonic-oscillator potential well and at a finite temperature. Semiclassical shell-structure components of the collective moment of inertia are obtained for any potential by using the periodic-orbit theory. We found semiclassically their relation to the free-energy shell corrections through the shell-structure components of the rigid-body moment of inertia of the statistically equilibrium rotation in terms of short periodic orbits. The shell effects in the moment of inertia exponentially disappear with increasing temperature. For the case of the harmonic-oscillator potential, one observes a perfect agreement of the semiclassical and quantum shell-structure components of the free energy and the moment of inertia for several critical bifurcation deformations and several temperatures.

  16. Optical properties of core-shell and multi-shell nanorods

    Science.gov (United States)

    Mokkath, Junais Habeeb; Shehata, Nader

    2018-05-01

    We report a first-principles time dependent density functional theory study of the optical response modulations in bimetallic core-shell (Na@Al and Al@Na) and multi-shell (Al@Na@Al@Na and Na@Al@Na@Al: concentric shells of Al and Na alternate) nanorods. All of the core-shell and multi-shell configurations display highly enhanced absorption intensity with respect to the pure Al and Na nanorods, showing sensitivity to both composition and chemical ordering. Remarkably large spectral intensity enhancements were found in a couple of core-shell configurations, indicative that optical response averaging based on the individual components can not be considered as true as always in the case of bimetallic core-shell nanorods. We believe that our theoretical results would be useful in promising applications depending on Aluminum-based plasmonic materials such as solar cells and sensors.

  17. On the core-mass-shell-luminosity relation for shell-burning stars

    International Nuclear Information System (INIS)

    Jeffery, C.S.; Saint Andrews Univ.

    1988-01-01

    Core-mass-shell-luminosity relations for several types of shell-burning star have been calculated using simultaneous differential equations derived from simple homology approximations. The principal objective of obtaining a mass-luminosity relation for helium giants was achieved. This relation gives substantially higher luminosities than the equivalent relation for H-shell stars with core masses greater than 1 solar mass. The algorithm for calculating mass-luminosity relations in this fashion was investigated in detail. Most of the assumptions regarding the physics in the shell do not play a critical role in determining the core-mass-shell-luminosity relation. The behaviour of the core-mass-core-radius relation for a growing degenerate core as a single unique function of mass and growth rate needs to be defined before a single core-mass-shell-luminosity relation for all H-shell stars can be obtained directly from the homology approximations. (author)

  18. Faraday Wave Turbulence on a Spherical Liquid Shell

    Science.gov (United States)

    Holt, R. Glynn; Trinh, Eugene H.

    1996-01-01

    Millimeter-radius liquid shells are acoustically levitated in an ultrasonic field. Capillary waves are observed on the shells. At low energies (minimal acoustic amplitude, thick shell) a resonance is observed between the symmetric and antisymmetric thin film oscillation modes. At high energies (high acoustic pressure, thin shell) the shell becomes fully covered with high-amplitude waves. Temporal spectra of scattered light from the shell in this regime exhibit a power-law decay indicative of turbulence.

  19. Gravity on-shell diagrams

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, Enrico [Walter Burke Institute for Theoretical Physics, California Institute of Technology,Pasadena, CA 91125 (United States); Trnka, Jaroslav [Center for Quantum Mathematics and Physics (QMAP),Department of Physics, University of California,Davis, CA 95616 (United States)

    2016-11-22

    We study on-shell diagrams for gravity theories with any number of supersymmetries and find a compact Grassmannian formula in terms of edge variables of the graphs. Unlike in gauge theory where the analogous form involves only dlog-factors, in gravity there is a non-trivial numerator as well as higher degree poles in the edge variables. Based on the structure of the Grassmannian formula for N=8 supergravity we conjecture that gravity loop amplitudes also possess similar properties. In particular, we find that there are only logarithmic singularities on cuts with finite loop momentum and that poles at infinity are present, in complete agreement with the conjecture presented in http://dx.doi.org/10.1007/JHEP06(2015)202.

  20. Stability of accelerated metal shells

    International Nuclear Information System (INIS)

    Tahsiri, H.

    1976-01-01

    A systematic treatment has been developed for the Rayleigh-Taylor instability of an accelerated liner. It is applicable to one-dimensional models either compressible or incompressible. With this model several points have been clarified. For an incompressible liner model, the Rayleigh-Taylor instability will have about five e-folding periods and the usual growth rate is independent of the current distribution or current rise time. Adequate stability will therefore depend on the magnitude of the initial perturbations or the precision of the initial liner and the thickness over which the shell is accelerated. However, for a compressible model, theory predicts that the current rise time is important and the Rayleigh-Taylor instability is suppressed if the current rise time is less than the shock transit time

  1. Angular momentum dependence of the distribution of shell model eigenenergies

    International Nuclear Information System (INIS)

    Yen, M.K.

    1974-01-01

    In the conventional shell model calculation the many-particle energy matrices are constructed and diagonalized for definite angular momentum and parity. However the resulting set of eigenvalues possess a near normal behavior and hence a simple statistical description is possible. Usually one needs only about four parameters to capture the average level densities if the size of the set is not too small. The parameters are essentially moments of the distribution. But the difficulty lies in the yet unsolved problem of calculating moments in the fixed angular momentum subspace. We have derived a formula to approximate the angular momentum projection dependence of any operator averaged in a shell model basis. This approximate formula which is a truncated series in Hermite polynomials has been proved very good numerically and justified analytically for large systems. Applying this formula to seven physical cases we have found that the fixed angular momentum projection energy centroid, width and higher central moments can be obtained accurately provided for even-even nuclei the even and odd angular momentum projections are treated separately. Using this information one can construct the energy distribution for fixed angular momentum projection assuming normal behavior. Then the fixed angular momentum level densities are deduced and spectra are extracted. Results are in reasonably good agreement with the exact values although not as good as those obtained using exact fixed angular momentum moments. (Diss. Abstr. Int., B)

  2. Axisymmetric vibrations of thick shells of revolution

    International Nuclear Information System (INIS)

    Suzuki, Katsuyoshi; Kosawada, Tadashi; Takahashi, Shin

    1983-01-01

    Axisymmetric shells of revolution are used for chemical plants, nuclear power plants, aircrafts, structures and so on, and the elucidation of their free vibration is important for the design. In this study, the axisymmetric vibration of a barrel-shaped shell was analyzed by the modified thick shell theory. The Lagrangian during one period of the vibration of a shell of revolution was determined, and from its stopping condition, the vibration equations and the boundary conditions were derived. The vibration equations were analyzed strictly by using the series solution. Moreover, the basic equations for the strain of a shell and others were based on those of Love. As the examples of numerical calculation, the natural frequency and vibration mode of the symmetrical shells of revolution fixed at both ends and supported at both ends were determined, and their characteristics were clarified. By comparing the results of this study with the results by thin shell theory, the effects of shearing deformation and rotary inertia on the natural frequency and vibration mode were clarified. The theoretical analysis and the numerical calculation are described. The effects of shearing deformation and rotary inertia on the natural frequency became larger in the higher order vibration. The vibration mode did not much change in both theories. (Kako, I.)

  3. Importance-truncated shell model for multi-shell valence spaces

    Energy Technology Data Exchange (ETDEWEB)

    Stumpf, Christina; Vobig, Klaus; Roth, Robert [Institut fuer Kernphysik, TU Darmstadt (Germany)

    2016-07-01

    The valence-space shell model is one of the work horses in nuclear structure theory. In traditional applications, shell-model calculations are carried out using effective interactions constructed in a phenomenological framework for rather small valence spaces, typically spanned by one major shell. We improve on this traditional approach addressing two main aspects. First, we use new effective interactions derived in an ab initio approach and, thus, establish a connection to the underlying nuclear interaction providing access to single- and multi-shell valence spaces. Second, we extend the shell model to larger valence spaces by applying an importance-truncation scheme based on a perturbative importance measure. In this way, we reduce the model space to the relevant basis states for the description of a few target eigenstates and solve the eigenvalue problem in this physics-driven truncated model space. In particular multi-shell valence spaces are not tractable otherwise. We combine the importance-truncated shell model with refined extrapolation schemes to approximately recover the exact result. We present first results obtained in the importance-truncated shell model with the newly derived ab initio effective interactions for multi-shell valence spaces, e.g., the sdpf shell.

  4. Free vibration analysis of delaminated composite shells using different shell theories

    International Nuclear Information System (INIS)

    Nanda, Namita; Sahu, S.K.

    2012-01-01

    Free vibration response of laminated composite shells with delamination is presented using the finite element method based on first order shear deformation theory. The shell theory used is the extension of dynamic, shear deformable theory according to the Sanders' first approximation for doubly curved shells, which can be reduced to Love's and Donnell's theories by means of tracers. An eight-noded C 0 continuity, isoparametric quadrilateral element with five degrees of freedom per node is used in the formulation. For modeling the delamination, multipoint constraint algorithm is incorporated in the finite element code. The natural frequencies of the delaminated cylindrical (CYL), spherical (SPH) and hyperbolic paraboloid (HYP) shells are determined by using the above mentioned shell theories, namely Sanders', Love's, and Donnell's. The validity of the present approach is established by comparing the authors' results with those available in the literature. Additional studies on free vibration response of CYL, SPH and HYP shells are conducted to assess the effects of delamination size and number of layers considering all three shell theories. It is shown that shell theories according to Sanders and Love always predict practically identical frequencies. Donnell's theory gives reliable results only for shallow shells. Moreover, the natural frequency is found to be very sensitive to delamination size and number of layers in the shell.

  5. Bending stresses in Facetted Glass Shells

    DEFF Research Database (Denmark)

    Bagger, Anne; Jönsson, Jeppe; Almegaard, Henrik

    2008-01-01

    A shell structure of glass combines a highly effective structural principle with a material of optimal permeability to light. A facetted shell structure has a piecewise plane geometry, and together the facets form an approximation to a curved surface. A distributed load on a plane-based facetted...... structure will locally cause bending moments in the loaded facets. The bending stresses are dependent on the stiffness of the joints. Approximate solutions are developed to estimate the magnitude of the bending stresses. A FE-model of a facetted glass shell structure is used to validate the expressions...

  6. Strontium and fluorine in tuatua shells

    International Nuclear Information System (INIS)

    Trompetter, W.J.; Coote, G.E.

    1993-01-01

    This report describes the research to date on the elemental distributions of strontium, calcium, and fluorine in a collection of 24 tuatua shells (courtesy of National Museum). Variations in elemental concentrations were measured in the shell cross-sections using a scanning proton microprobe (PIXE and PIGME). In this paper we report the findings to date, and present 2-D measurement scans as illustrative grey-scale pictures. Our results support the hypothesis that increased strontium concentrations are deposited in the shells during spawning, and that fluorine concentration is proportional to growth rate. (author). 15 refs.; 13 figs.; 1 appendix

  7. Gross shell structure of moments of inertia

    International Nuclear Information System (INIS)

    Deleplanque, M.A.; Frauendorf, S.; Pashkevich, V.V.; Chu, S.Y.; Unzhakova, A.

    2002-01-01

    Average yrast moments of inertia at high spins, where the pairing correlations are expected to be largely absent, were found to deviate from the rigid-body values. This indicates that shell effects contribute to the moment of inertia. We discuss the gross dependence of moments of inertia and shell energies on the neutron number in terms of the semiclassical periodic orbit theory. We show that the ground-state shell energies, nuclear deformations and deviations from rigid-body moments of inertia are all due to the same periodic orbits

  8. Thin shells joining local cosmic string geometries

    Energy Technology Data Exchange (ETDEWEB)

    Eiroa, Ernesto F. [Universidad de Buenos Aires, Ciudad Universitaria Pabellon I, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), Buenos Aires (Argentina); Rubin de Celis, Emilio; Simeone, Claudio [Universidad de Buenos Aires, Ciudad Universitaria Pabellon I, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Ciudad Universitaria Pabellon I, IFIBA-CONICET, Buenos Aires (Argentina)

    2016-10-15

    In this article we present a theoretical construction of spacetimes with a thin shell that joins two different local cosmic string geometries. We study two types of global manifolds, one representing spacetimes with a thin shell surrounding a cosmic string or an empty region with Minkowski metric, and the other corresponding to wormholes which are not symmetric across the throat located at the shell. We analyze the stability of the static configurations under perturbations preserving the cylindrical symmetry. For both types of geometries we find that the static configurations can be stable for suitable values of the parameters. (orig.)

  9. Thin shells joining local cosmic string geometries

    International Nuclear Information System (INIS)

    Eiroa, Ernesto F.; Rubin de Celis, Emilio; Simeone, Claudio

    2016-01-01

    In this article we present a theoretical construction of spacetimes with a thin shell that joins two different local cosmic string geometries. We study two types of global manifolds, one representing spacetimes with a thin shell surrounding a cosmic string or an empty region with Minkowski metric, and the other corresponding to wormholes which are not symmetric across the throat located at the shell. We analyze the stability of the static configurations under perturbations preserving the cylindrical symmetry. For both types of geometries we find that the static configurations can be stable for suitable values of the parameters. (orig.)

  10. Strontium clusters: electronic and geometry shell effects

    DEFF Research Database (Denmark)

    Lyalin, Andrey G.; Solov'yov, Ilia; Solov'yov, Andrey V.

    2008-01-01

    charged strontium clusters consisting of up to 14 atoms, average bonding distances, electronic shell closures, binding energies per atom, and spectra of the density of electronic states (DOS). It is demonstrated that the size-evolution of structural and electronic properties of strontium clusters...... is governed by an interplay of the electronic and geometry shell closures. Influence of the electronic shell effects on structural rearrangements can lead to violation of the icosahedral growth motif of strontium clusters. It is shown that the excessive charge essentially affects the optimized geometry...

  11. Amplitude structure of off-shell processes

    International Nuclear Information System (INIS)

    Fearing, H.W.; Goldstein, G.R.; Moravcsik, M.J.

    1984-01-01

    The structure of M matrices, or scattering amplitudes, and of potentials for off-shell processes is discussed with the objective of determining how one can obtain information on off-shell amplitudes of a process in terms of the physical observables of a larger process in which the first process is embedded. The procedure found is inevitably model dependent, but within a particular model for embedding, a determination of the physically measurable amplitudes of the larger process is able to yield a determination of the off-shell amplitudes of the embedded process

  12. Atomic mass formula with linear shell terms

    International Nuclear Information System (INIS)

    Uno, Masahiro; Yamada, Masami; Ando, Yoshihira; Tachibana, Takahiro.

    1981-01-01

    An atomic mass formula is constructed in the form of a sum of gross terms and empirical linear shell terms. Values of the shell parameters are determined after the statistical method of Uno and Yamada, Which is characterized by inclusion of the error inherent in the mass formula. The resulting formula reproduces the input masses with the standard deviation of 393 keV. A prescription is given for estimating errors of calculated masses. The mass formula is compared with recent experimental data of Rb, Cs and Fr isotopes, which are not included in the input data, and also with the constant-shell-term formula of Uno and Yamada. (author)

  13. Analysis of anisotropic shells containing flowing fluid

    International Nuclear Information System (INIS)

    Lakis, A.A.

    1983-01-01

    A general theory for the dynamic analysis of anisotropic thin cylindrical shells containing flowing fluid is presented. The shell may be uniform or non-uniform, provided it is geometrically axially symmetric. This is a finite- element theory, using cylindrical finite elements, but the displacement functions are determined by using classical shell theory. A new solution of the wave equation of the liquid finite element leads to an expression of the fluid pressure, p, as a function of the nodal displacements of the element and three operative forces (inertia, centrifugal and Coriolis) of the moving fluid. (Author) [pt

  14. New oil skimmer from shell

    Energy Technology Data Exchange (ETDEWEB)

    1978-06-01

    Under a program initiated by the US Coast Guard (USCG), Shell Development Co. has developed the Zero-Relative Velocity Skimmer (ZRVS) (Abstract No. 24-30285) which can recover spilled oil in currents up to eight knots. Tests of a full-scale mockup of the system gave excellent results up to the test limit of eight knots and in waves up to 2 ft high. Conventional oil skimmers slow down the floating oil relative to the water so that it can be contained and collected. But when the relative velocity of water and skimmer exceeds 1 to 2 knots, turbulence caused by the skimmer's surface piercing equipment leads to oil escaping. The ZRVS combats this by laying twin floating, adsorbent belts on the surface so they move at the same speed as the water and oil relative to the skimmer. With no relative velocity between them, turbulence is removed, allowing the skimmer to operate effectively in fast currents. The skimmer is a 41 ft catamaran, built in three sections so it can be transported in two aircraft and assembled at the port nearest the spill. The first prototype is due to be completed at the USCG shipyard in the summer of 1978.

  15. Casimir effect in spherical shells

    International Nuclear Information System (INIS)

    Ruggiero, J.R.

    1985-01-01

    The analytic regularization method is applied to study the Casimir effect for spherical cavities. Although many works have been presented in the past few years, problems related to the elimination of the regulator parameter still remain. A way to calculate the zero point energy of a perfectly conducting spherical shell which is a miscellaneous of those presented early is here proposed, How a cancelation of divergent terms occurs and how a finite parte is obtained after the elimination of the regulator parameter is shown. As a by-product the zero point energy of the interior vibration modes is obtained and this has some relevance to the quarks bag model. This relev ance is also discussed. The calculation of the energy fom the density view is also discussed. Some works in this field are criticized. The logarithmic divergent terms in the zero point energy are studied when the interior and exterior of the sphere are considered as a medium not dispersive and characterized by a dielectric constants ε 1 and ε 2 and peermeability constants μ 1 and μ 2 respectivelly. The logarithmic divergent terms are not present in the case of ε i μ i =K, with K some constant and i=1,2. (author) [pt

  16. Extensions to a nonlinear finite element axisymmetric shell model based on Reissner's shell theory

    International Nuclear Information System (INIS)

    Cook, W.A.

    1981-01-01

    A finite element shell-of-revolution model has been developed to analyze shipping containers under severe impact conditions. To establish the limits for this shell model, I studied the basic assumptions used in its development; these are listed in this paper. Several extensions were evident from the study of these limits: a thick shell, a plastic hinge, and a linear normal stress. (orig./HP)

  17. June 9-10, 2015: A case study of the Great Plains Low-Level Jet during PECAN (Plains Elevated Convection at Night)

    Science.gov (United States)

    Sullivan, Sharon M.

    Observations as part of the Plains Elevated Convection at Night (PECAN) campaign have allowed for an examination of the thermodynamic and dynamic structure of the LLJ using ground-based and airborne measurements in central Kansas. A shallow jet with wind speeds near 20 m s-1 formed during the nighttime hours on 10 June 2015. The University of Wyoming King Air research aircraft conducted two research flights beginning at sunset and ending near dawn, capturing the full evolution of the LLJ. Each flight included a series of vertical sawtooth maneuvers and isobaric legs along a fixed track at 38.7°N between 98.89°W and 100.3°W. This case featured classic signatures of the LLJ, including but not limited to the inertial oscillation of the ageostrophic wind. Forcing of the LLJ was analyzed using cross sections of D-values that allowed the vertical structure of the horizontal pressure gradient and hence thermal wind to be examined. A series of numerical simulations of the 10 June 2015 case study were made using the Weather Research and Forecasting (WRF) model to compare with observations. Output grids indicated that a temperature gradient of 6°C over 500 km was present between the surface and 850 hPa. Warmer temperatures were found to the west from the surface up to 600 hPa. The 600 hPa geostrophic winds were from the north. As a result, only weak southerly geostrophic winds were able to develop at the surface. The terrain-induced thermal wind was sufficiently large to overcome the adverse pressure gradient in the free atmosphere, but could only produce weak southerly geostrophic winds at the surface of about 11.4 m s-1.

  18. Anticavitation and Differential Growth in Elastic Shells

    KAUST Repository

    Moulton, Derek E.; Goriely, Alain

    2010-01-01

    infinite growth or resorption is imposed at the inner surface of the shell. However, void collapse can occur in a limiting sense when radial and circumferential growth are properly balanced. Growth functions which diverge or vanish at a point arise

  19. Wireless energy transfer between anisotropic metamaterials shells

    Energy Technology Data Exchange (ETDEWEB)

    Díaz-Rubio, Ana; Carbonell, Jorge; Sánchez-Dehesa, José, E-mail: jsdehesa@upv.es

    2014-06-15

    The behavior of strongly coupled Radial Photonic Crystals shells is investigated as a potential alternative to transfer electromagnetic energy wirelessly. These sub-wavelength resonant microstructures, which are based on anisotropic metamaterials, can produce efficient coupling phenomena due to their high quality factor. A configuration of selected constitutive parameters (permittivity and permeability) is analyzed in terms of its resonant characteristics. The coupling to loss ratio between two coupled resonators is calculated as a function of distance, the maximum (in excess of 300) is obtained when the shells are separated by three times their radius. Under practical conditions an 83% of maximum power transfer has been also estimated. -- Highlights: •Anisotropic metamaterial shells exhibit high quality factors and sub-wavelength size. •Exchange of electromagnetic energy between shells with high efficiency is analyzed. •Strong coupling is supported with high wireless transfer efficiency. •End-to-end energy transfer efficiencies higher than 83% can be predicted.

  20. Single Shell Tank (SST) Program Plan

    International Nuclear Information System (INIS)

    HAASS, C.C.

    2000-01-01

    This document provides an initial program plan for retrieval of the single-shell tank waste. Requirements, technical approach, schedule, organization, management, and cost and funding are discussed. The program plan will be refined and updated in fiscal year 2000

  1. Wireless energy transfer between anisotropic metamaterials shells

    International Nuclear Information System (INIS)

    Díaz-Rubio, Ana; Carbonell, Jorge; Sánchez-Dehesa, José

    2014-01-01

    The behavior of strongly coupled Radial Photonic Crystals shells is investigated as a potential alternative to transfer electromagnetic energy wirelessly. These sub-wavelength resonant microstructures, which are based on anisotropic metamaterials, can produce efficient coupling phenomena due to their high quality factor. A configuration of selected constitutive parameters (permittivity and permeability) is analyzed in terms of its resonant characteristics. The coupling to loss ratio between two coupled resonators is calculated as a function of distance, the maximum (in excess of 300) is obtained when the shells are separated by three times their radius. Under practical conditions an 83% of maximum power transfer has been also estimated. -- Highlights: •Anisotropic metamaterial shells exhibit high quality factors and sub-wavelength size. •Exchange of electromagnetic energy between shells with high efficiency is analyzed. •Strong coupling is supported with high wireless transfer efficiency. •End-to-end energy transfer efficiencies higher than 83% can be predicted

  2. Computational mechanics of nonlinear response of shells

    Energy Technology Data Exchange (ETDEWEB)

    Kraetzig, W.B. (Bochum Univ. (Germany, F.R.). Inst. fuer Statik und Dynamik); Onate, E. (Universidad Politecnica de Cataluna, Barcelona (Spain). Escuela Tecnica Superior de Ingenieros de Caminos) (eds.)

    1990-01-01

    Shell structures and their components are utilized in a wide spectrum of engineering fields reaching from space and aircraft structures, pipes and pressure vessels over liquid storage tanks, off-shore installations, cooling towers and domes, to bodyworks of motor vehicles. Of continuously increasing importance is their nonlinear behavior, in which large deformations and large rotations are involved as well as nonlinear material properties. The book starts with a survey about nonlinear shell theories from the rigorous point of view of continuum mechanics, this starting point being unavoidable for modern computational concepts. There follows a series of papers on nonlinear, especially unstable shell responses, which draw computational connections to well established tools in the field of static and dynamic stability of systems. Several papers are then concerned with new finite element derivations for nonlinear shell problems, and finally a series of authors contribute to specific applications opening a small window of the above mentioned wide spectrum. (orig./HP) With 159 figs.

  3. Single Shell Tank (SST) Program Plan

    Energy Technology Data Exchange (ETDEWEB)

    HAASS, C.C.

    2000-03-21

    This document provides an initial program plan for retrieval of the single-shell tank waste. Requirements, technical approach, schedule, organization, management, and cost and funding are discussed. The program plan will be refined and updated in fiscal year 2000.

  4. Hydration shells exchange charge with their protein

    DEFF Research Database (Denmark)

    Abitan, Haim; Lindgård, Per-Anker; Nielsen, Bjørn Gilbert

    2010-01-01

    . In our experiments, the amplitude of an ultrasonic pressure wave is gradually increased (0–20 atm) while we simultaneously measure the Raman spectra from the hydrated protein (β-lactoglobulin and lysozyme). We detected two types of spectral changes: first, up to 70% increase in the intensity......Investigation of the interaction between a protein and its hydration shells is an experimental and theoretical challenge. Here, we used ultrasonic pressure waves in aqueous solutions of a protein to explore the conformational states of the protein and its interaction with its hydration shells...... the presence of an ultrasonic pressure, a protein and its hydration shells are in thermodynamic and charge equilibrium, i.e. a protein and its hydration shells exchange charges. The ultrasonic wave disrupts these equilibria which are regained within 30–45 min after the ultrasonic pressure is shut off....

  5. Quark shell model using projection operators

    International Nuclear Information System (INIS)

    Ullah, N.

    1988-01-01

    Using the projection operators in the quark shell model, the wave functions for proton are calculated and expressions for calculating the wave function of neutron and also magnetic moment of proton and neutron are derived. (M.G.B.)

  6. Computational mechanics of nonlinear response of shells

    International Nuclear Information System (INIS)

    Kraetzig, W.B.; Onate, E.

    1990-01-01

    Shell structures and their components are utilized in a wide spectrum of engineering fields reaching from space and aircraft structures, pipes and pressure vessels over liquid storage tanks, off-shore installations, cooling towers and domes, to bodyworks of motor vehicles. Of continuously increasing importance is their nonlinear behavior, in which large deformations and large rotations are involved as well as nonlinear material properties. The book starts with a survey about nonlinear shell theories from the rigorous point of view of continuum mechanics, this starting point being unavoidable for modern computational concepts. There follows a series of papers on nonlinear, especially unstable shell responses, which draw computational connections to well established tools in the field of static and dynamic stability of systems. Several papers are then concerned with new finite element derivations for nonlinear shell problems, and finally a series of authors contribute to specific applications opening a small window of the above mentioned wide spectrum. (orig./HP) With 159 figs

  7. Acoustic coupling of two parallel shells in compressible fluid

    International Nuclear Information System (INIS)

    Gerges, S.N.Y.

    1982-01-01

    Modifications are done in the acoustic impedance for a vibrating shell, due to the pressure of another similar shell. The multi-analysis method of scattering is used. The results of the impedance in function of the shell radius, the wave length, the distance between the shell axis and its vibration models are presented. (E.G.) [pt

  8. Sexual selection on land snail shell ornamentation: a hypothesis that may explain shell diversity

    Directory of Open Access Journals (Sweden)

    Schilthuizen Menno

    2003-06-01

    Full Text Available Abstract Background Many groups of land snails show great interspecific diversity in shell ornamentation, which may include spines on the shell and flanges on the aperture. Such structures have been explained as camouflage or defence, but the possibility that they might be under sexual selection has not previously been explored. Presentation of the hypothesis The hypothesis that is presented consists of two parts. First, that shell ornamentation is the result of sexual selection. Second, that such sexual selection has caused the divergence in shell shape in different species. Testing the hypothesis The first part of the hypothesis may be tested by searching for sexual dimorphism in shell ornamentation in gonochoristic snails, by searching for increased variance in shell ornamentation relative to other shell traits, and by mate choice experiments using individuals with experimentally enhanced ornamentation. The second part of the hypothesis may be tested by comparing sister groups and correlating shell diversity with degree of polygamy. Implications of the hypothesis If the hypothesis were true, it would provide an explanation for the many cases of allopatric evolutionary radiation in snails, where shell diversity cannot be related to any niche differentiation or environmental differences.

  9. Study of thiophene inner shell photofragmentation

    International Nuclear Information System (INIS)

    Mundim, M.S.P.; Mocellin, A.; Makiuchi, N.; Naves de Brito, A.; Attie, M.; Correia, N.

    2007-01-01

    We investigated the inner shell photofragmentation of thiophene by time of flight (TOF) mass spectroscopy using multi-coincidence electron-ion techniques. Our main purpose was to understand aspects of molecular relaxation process after inner shell excitation and to search for bond break selectivity. Analyses of mass and branching ratios are presented and the results suggest different mechanisms and channel of fragmentation when compared with S 2p and C 1s excitations

  10. Study of thiophene inner shell photofragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Mundim, M.S.P. [Instituto de Fisica, Universidade de Brasilia-UnB, P.O. Box 04455, CEP 70919-970 Brasilia, DF (Brazil)], E-mail: spedrosa@fis.unb.br; Mocellin, A.; Makiuchi, N. [Instituto de Fisica, Universidade de Brasilia-UnB, P.O. Box 04455, CEP 70919-970 Brasilia, DF (Brazil); Naves de Brito, A. [Instituto de Fisica, Universidade de Brasilia-UnB, P.O. Box 04455, CEP 70919-970 Brasilia, DF (Brazil); Laboratorio Nacional de Luz Sincrotron-LNLS, P.O. Box 6192, CEP 13084-971 Campinas, SP (Brazil); Attie, M. [Departamento de Ciencias Biologicas, Universidade Estadual de Santa Cruz, UESC Rodovia Ilheus-Itabuna, km 16, CEP 45 650 000 Ilheus, BA (Brazil); Correia, N. [Departamento de Ciencias Exatas e Tecnologicas, Universidade Estadual de Santa Cruz, UESC, Rodovia Ilheus-Itabuna, km 16, CEP 45 650 000 Ilheus, BA (Brazil); Departament of Quantum Chemistry, University of Uppsala, P.O. Box 518, 751 21 Uppsala (Sweden)

    2007-03-15

    We investigated the inner shell photofragmentation of thiophene by time of flight (TOF) mass spectroscopy using multi-coincidence electron-ion techniques. Our main purpose was to understand aspects of molecular relaxation process after inner shell excitation and to search for bond break selectivity. Analyses of mass and branching ratios are presented and the results suggest different mechanisms and channel of fragmentation when compared with S 2p and C 1s excitations.

  11. Walnut shells: replacement for natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Goss, J R; Williams, R O

    1977-11-01

    A method of extracting useful energy from cracked walnut shells has been developed by the University of California in co-operation with Diamond/Sunsweet, Inc., and the California Energy Resources Conservation and Development Commission. The technique involves converting the shells to producer gas, a low-Btu gas in which the major combustible components are carbon monoxide (20 to 30%) and hydrogen (10 to 15%).

  12. Double shell tank waste analysis plan

    International Nuclear Information System (INIS)

    Mulkey, C.H.; Jones, J.M.

    1994-01-01

    Waste analysis plan for the double shell tanks. SD-WM-EV-053 is Superseding SD-WM-EV-057.This document provides the plan for obtaining information needed for the safe waste handling and storage of waste in the Double Shell Tank Systems. In Particular it addresses analysis necessary to manage waste according to Washington Administrative Code 173-303 and Title 40, parts 264 and 265 of the Code of Federal Regulations

  13. Dehydration of core/shell fruits

    OpenAIRE

    Liu, Y.; Yang, Xiaosong; Cao, Y.; Wang, Z.; Chen, B.; Zhang, Jian J.; Zhang, H.

    2015-01-01

    Dehydrated core/shell fruits, such as jujubes, raisins and plums, show very complex buckles and wrinkles on their exocarp. It is a challenging task to model such complicated patterns and their evolution in a virtual environment even for professional animators. This paper presents a unified physically-based approach to simulate the morphological transformation for the core/shell fruits in the dehydration process. A finite element method (FEM), which is based on the multiplicative decomposition...

  14. Engineered inorganic core/shell nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mélinon, Patrice, E-mail: patrice.melinon@univ-lyon1.fr [Institut Lumière matière Université Claude Bernard Lyon 1 et CNRS et OMNT, Domaine Scientifique de la Doua, Bâtiment Léon Brillouin, 43 Boulevard du 11 Novembre 1918, F 69622 Villeurbanne (France); Begin-Colin, Sylvie [IPCMS et OMNT, 23 rue du Loess BP 43, 67034 STRASBOURG Cedex 2 (France); Duvail, Jean Luc [IMN UMR 6502 et OMNT Campus Sciences : 2 rue de la Houssinire, BP32229, 44322 Nantes Cedex3 (France); Gauffre, Fabienne [SPM et OMNT : Institut des sciences chimiques de Rennes - UMR 6226, 263 Avenue du General Leclerc, CS 74205, 35042 RENNES Cedex (France); Boime, Nathalie Herlin [IRAMIS-NIMBE, Laboratoire Francis Perrin (CEA CNRS URA 2453) et OMNT, Bat 522, CEA Saclay, 91191 Gif sur Yvette Cedex (France); Ledoux, Gilles [Institut Lumière Matière Université Claude Bernard Lyon 1 et CNRS et OMNT, Domaine Scientifique de la Doua, Bâtiment Alfred Kastler 43 Boulevard du 11 Novembre 1918 F 69622 Villeurbanne (France); Plain, Jérôme [Universit de technologie de Troyes LNIO-ICD, CNRS et OMNT 12 rue Marie Curie - CS 42060 - 10004 Troyes cedex (France); Reiss, Peter [CEA Grenoble, INAC-SPrAM, UMR 5819 CEA-CNRS-UJF et OMNT, Grenoble cedex 9 (France); Silly, Fabien [CEA, IRAMIS, SPEC, TITANS, CNRS 2464 et OMNT, F-91191 Gif sur Yvette (France); Warot-Fonrose, Bénédicte [CEMES-CNRS, Université de Toulouse et OMNT, 29 rue Jeanne Marvig F 31055 Toulouse (France)

    2014-10-20

    It has been for a long time recognized that nanoparticles are of great scientific interest as they are effectively a bridge between bulk materials and atomic structures. At first, size effects occurring in single elements have been studied. More recently, progress in chemical and physical synthesis routes permitted the preparation of more complex structures. Such structures take advantages of new adjustable parameters including stoichiometry, chemical ordering, shape and segregation opening new fields with tailored materials for biology, mechanics, optics magnetism, chemistry catalysis, solar cells and microelectronics. Among them, core/shell structures are a particular class of nanoparticles made with an inorganic core and one or several inorganic shell layer(s). In earlier work, the shell was merely used as a protective coating for the core. More recently, it has been shown that it is possible to tune the physical properties in a larger range than that of each material taken separately. The goal of the present review is to discuss the basic properties of the different types of core/shell nanoparticles including a large variety of heterostructures. We restrict ourselves on all inorganic (on inorganic/inorganic) core/shell structures. In the light of recent developments, the applications of inorganic core/shell particles are found in many fields including biology, chemistry, physics and engineering. In addition to a representative overview of the properties, general concepts based on solid state physics are considered for material selection and for identifying criteria linking the core/shell structure and its resulting properties. Chemical and physical routes for the synthesis and specific methods for the study of core/shell nanoparticle are briefly discussed.

  15. P-shell hyperon binding energies

    International Nuclear Information System (INIS)

    Koetsier, D.; Amos, K.

    1991-01-01

    A shell model for lambda hypernuclei has been used to determine the binding energy of the hyperon in nuclei throughout the p shell. Conventional (Cohen and Kurath) potential energies for nucleon-nucleon interactions were used with hyperon-nucleon interactions taken from Nijmegen one boson exchange potentials. The hyperon binding energies calculated from these potentials compare well with measured values. 7 refs., 2 figs

  16. Dynamic nonlinear analysis of shells of revolution

    International Nuclear Information System (INIS)

    Riesemann, W.A. von; Stricklin, J.A.; Haisler, W.E.

    1975-01-01

    Over the past few years a series of finite element computer programs have been developed at Texas A and M University for the static and dynamic nonlinear analysis of shells of revolution. This paper discusses one of these, DYNAPLAS, which is a program for the transient response of ring stiffened shells of revolution subjected to either asymmetric initial velocities or to asymmetric pressure loadings. Both material and geometric nonlinearities may be considered. (Auth.)

  17. Shell effects in the superasymmetric fission

    CERN Document Server

    Mirea, M

    2002-01-01

    A new formalism based on the Landau-Zener promotion mechanism intends to explain the fine structure of alpha and cluster decay. The analysis of this phenomenon is accomplished by following the modality in which the shells are reorganized during the decay process beginning with the initial ground state of the parent towards the final configuration of two separated nuclei. A realistic level scheme is obtained in the framework of the superasymmetric two-center shell model. (author)

  18. Shape-controlled synthesis of Pt-Pd core-shell nanoparticles exhibiting polyhedral morphologies by modified polyol method

    International Nuclear Information System (INIS)

    Long, Nguyen Viet; Asaka, Toru; Matsubara, Takashi; Nogami, Masayuki

    2011-01-01

    Pt-Pd core-shell nanoparticles were synthesized by a simple synthetic method. First, Pt nanoparticles were synthesized in a controlled manner via the reduction of chloroplantinic acid hexahydrate in ethylene glycol (EG) at 160 deg. C in the presence of silver nitrate and the stabilization of polyvinylpyrrolidon. AgNO 3 used acts as a structure-modifying agent to the morphology of the Pt nanoparticles. These Pt nanoparticles function as the seeds for the successive reduction of sodium tetrachloropalladate (II) hydrate in EG under stirring for 15 min at 160 deg. C in order to synthesize Pt-Pd core-shell nanoparticles. To characterize the as-prepared Pt-Pd nanoparticles, transmission electron microscopy (TEM) and high-resolution TEM are used. The high-resolution elemental mappings were carried out using the combination of scanning TEM and X-ray energy-dispersive spectroscopy. The results also demonstrate the homogeneous nucleation and growth of the Pd metal shell on the definite Pt core. The synthesized Pt-Pd core-shell nanoparticles exhibit a sharp and polyhedral morphology. The epitaxial growth of the controlled Pd shells on the Pt cores via a polyol method was observed. It is suggested that Frank-van der Merwe and Stranski-Krastanov growth modes coexisted in the nucleation and growth of Pt-Pd core-shell nanoparticles.

  19. An equations of motion approach for open shell systems

    International Nuclear Information System (INIS)

    Yeager, D.L.; McKoy, V.

    1975-01-01

    A straightforward scheme is developed for extending the equations of motion formalism to systems with simple open shell ground states. Equations for open shell random phase approximation (RPA) are given for the cases of one electron outside of a closed shell in a nondegenerate molecular orbital and for the triplet ground state with two electrons outside of a closed shell in degenerate molecular orbitals. Applications to other open shells and extension of the open shell EOM to higher orders are both straightforward. Results for the open shell RPA for lithium atom and oxygen molecule are given

  20. Axisymmetric vibrations of thin shells of revolution

    International Nuclear Information System (INIS)

    Suzuki, Katsuyoshi; Kikuchi, Norio; Kosawada, Tadashi; Takahashi, Shin

    1983-01-01

    The problem of free vibration of axisymmetric shells of revolution is important in connection with the design of pressure vessels, chemical equipment, aircrafts, structures and so on. In this study, the axisymmetrical vibration of a thin shell of revolution having a constant curvature in meridian direction was analyzed by thin shell theory. First, the Lagrangian during one period of the vibration of a shell of revolution was determined by the primary approximate theory of Love, and the vibration equations and boundary conditions were derived from its stopping condition. The vibration equations were strictly analyzed by using the series solution. The basic equations for the strain and strain energy of a shell were based on those of Novozhilov. As the examples of numerical calculation, the natural frequency and vibration mode of the symmetrical shells of revolution fixed at both ends and supported at both ends were determined, and their characteristics were clarified. The theory and the numerical calculation ore described. Especially in the frequency curves, the waving phenomena were observed frequently, which were not seen in non-axisymmetric vibration, accordingly also the vibration mode changed in complex state on the frequency curves of same order. The numerical calculation was carried out in the large computer center in Tohoku University. (Kako, I.)

  1. A new ejecta shell surrounding a Wolf-Rayet star in the LMC

    Science.gov (United States)

    Garnett, Donald R.; Chu, You-Hua

    1994-01-01

    We have obtained CCD spectra of newly discovered shell-like nebulae around the WN4 star Breysacher 13 and the WN1 star Breysacher 2 in the Large Magellanic Cloud (LMC). The shell around Br 13 shows definite signs of enrichment in both nitrogen and helium, having much stronger (N II) and He I emission lines than are seen in typical LMC H II regions. From the measured electron temperature of about 17,000 K in the shell, we derive He/H and N/O abundance ratios which are factors of 2 and more than 10 higher, respectively, than the average LMC interstellar values. The derived oxygen abundance in the Br 13 shell is down by a factor of 8 compared to the local LMC interstellar medium (ISM); however, the derived electron temperature is affected by the presence of an incomplete shock arising from the interaction of the stellar wind with photoionized material. This uncertainty does not affect the basic conclusion that the Br 13 shell is enriched by processed material from the Wolf-Rayet star. In contrast, the shell around Br 2 shows no clear evidence of enrichment. The nebular spectrum is characterized by extremely strong (O III) and He II emission and very weak (N II). We derive normal He, O, and N abundances from our spectrum. This object therefore appears to be simply a wind-blown structure associated with a relatively dense cloud near the Wolf-Rayet star, although the very high-ionization state of the gas is unusual for a nebula associated with a Wolf-Rayet star.

  2. Determination of shell energies. Nuclear deformations and fission barriers

    International Nuclear Information System (INIS)

    Koura, Hiroyuki; Tachibana, Takahiro; Uno, Masahiro; Yamada, Masami.

    1996-01-01

    We have been studying a method of determining nuclear shell energies and incorporating them into a mass formula. The main feature of this method lies in estimating shell energies of deformed nuclei from spherical shell energies. We adopt three assumptions, from which the shell energy of a deformed nucleus is deduced to be a weighted sum of spherical shell energies of its neighboring nuclei. This shell energy should be called intrinsic shell energy since the average deformation energy also acts as an effective shell energy. The ground-state shell energy of a deformed nucleus and its equilibrium shape can be obtained by minimizing the sum of these two energies with respect to variation of deformation parameters. In addition, we investigate the existence of fission isomers for heavy nuclei with use of the obtained shell energies. (author)

  3. Lessons Not Learned. The Other Shell Report 2004

    International Nuclear Information System (INIS)

    Harden, M.; Walker, N.; Griffiths, H.; Verweij, M.

    2005-06-01

    The third alternative Shell Corporate Social Responsibility (CSR) report is presented on behalf of several of the many communities that live on Shell's 'fencelines', next to Shell's refineries, depots and pipelines. This 2004 report builds on reports of the past two years 'Failing the Challenge', (2002) and 'Behind the Shine' (2003) which chronicled Shell's impacts around the world. It gives critical updates of Shell's performance over the past year

  4. Variation in Orthologous Shell-Forming Proteins Contribute to Molluscan Shell Diversity.

    Science.gov (United States)

    Jackson, Daniel J; Reim, Laurin; Randow, Clemens; Cerveau, Nicolas; Degnan, Bernard M; Fleck, Claudia

    2017-11-01

    Despite the evolutionary success and ancient heritage of the molluscan shell, little is known about the molecular details of its formation, evolutionary origins, or the interactions between the material properties of the shell and its organic constituents. In contrast to this dearth of information, a growing collection of molluscan shell-forming proteomes and transcriptomes suggest they are comprised of both deeply conserved, and lineage specific elements. Analyses of these sequence data sets have suggested that mechanisms such as exon shuffling, gene co-option, and gene family expansion facilitated the rapid evolution of shell-forming proteomes and supported the diversification of this phylum specific structure. In order to further investigate and test these ideas we have examined the molecular features and spatial expression patterns of two shell-forming genes (Lustrin and ML1A2) and coupled these observations with materials properties measurements of shells from a group of closely related gastropods (abalone). We find that the prominent "GS" domain of Lustrin, a domain believed to confer elastomeric properties to the shell, varies significantly in length between the species we investigated. Furthermore, the spatial expression patterns of Lustrin and ML1A2 also vary significantly between species, suggesting that both protein architecture, and the regulation of spatial gene expression patterns, are important drivers of molluscan shell evolution. Variation in these molecular features might relate to certain materials properties of the shells of these species. These insights reveal an important and underappreciated source of variation within shell-forming proteomes that must contribute to the diversity of molluscan shell phenotypes. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  5. The collective bands of positive parity states in odd-A (fp) shell nuclei

    International Nuclear Information System (INIS)

    Ahalpara, D.P.

    1979-01-01

    The low-lying collective bands of positive parity states in (fp) shell nuclei are described in the deformed Hartree-Fock method by projecting states of definite angular momenta from 'the lowest energy intrinsic states in (sd)sup(-1)(fp)sup(n+1) configurations. The modified Kuo-Brown effective interaction for (fp) shell and modified surface delta interaction (MSDI) for a hole in (sd) shell with a particle in (fp) shell have been used. The collective bands of states are in general well reproduced by the effective interactions. The excitation energies of the band head states are however off by about one MeV. The calculated magnetic moments of the band head j = 3/2 + states are in reasonable agreement with experiment. Using effective charges esub(p) = 1.33 e and esub(n) = 0.64 e fairly good agreement is obtained for E(2) transitions. The hindered M(1) transition strengths are reproduced to the correct order, however they are slightly higher compared to the experiment. (author)

  6. Revisiting chameleon gravity: Thin-shell and no-shell fields with appropriate boundary conditions

    International Nuclear Information System (INIS)

    Tamaki, Takashi; Tsujikawa, Shinji

    2008-01-01

    We derive analytic solutions of a chameleon scalar field φ that couples to a nonrelativistic matter in the weak gravitational background of a spherically symmetric body, paying particular attention to a field mass m A inside of the body. The standard thin-shell field profile is recovered by taking the limit m A r c →∞, where r c is a radius of the body. We show the existence of ''no-shell'' solutions where the field is nearly frozen in the whole interior of the body, which does not necessarily correspond to the 'zero-shell' limit of thin-shell solutions. In the no-shell case, under the condition m A r c >>1, the effective coupling of φ with matter takes the same asymptotic form as that in the thin-shell case. We study experimental bounds coming from the violation of equivalence principle as well as solar-system tests for a number of models including f(R) gravity and find that the field is in either the thin-shell or the no-shell regime under such constraints, depending on the shape of scalar-field potentials. We also show that, for the consistency with local gravity constraints, the field at the center of the body needs to be extremely close to the value φ A at the extremum of an effective potential induced by the matter coupling.

  7. On-shell and half-shell effects of the coulomb potential in quantum mechanics

    NARCIS (Netherlands)

    Maag, Jan Willem de

    1984-01-01

    In dit proefschrift wordt de Coulomb potentiaal in de nietrelativistische quantummechanica bestudeerd. Met gebruik van een streng wiskundige beschrijving onderzoeken we, in het bijzonder, on-shell en off-shell eigenschappen. De overeenkomsten en de verschillen met het geval van een glad afgeschermde

  8. Core-shell microspheres with porous nanostructured shells for liquid chromatography.

    Science.gov (United States)

    Ahmed, Adham; Skinley, Kevin; Herodotou, Stephanie; Zhang, Haifei

    2018-01-01

    The development of new stationary phases has been the key aspect for fast and efficient high-performance liquid chromatography separation with relatively low backpressure. Core-shell particles, with a solid core and porous shell, have been extensively investigated and commercially manufactured in the last decade. The excellent performance of core-shell particles columns has been recorded for a wide range of analytes, covering small and large molecules, neutral and ionic (acidic and basic), biomolecules and metabolites. In this review, we first introduce the advance and advantages of core-shell particles (or more widely known as superficially porous particles) against non-porous particles and fully porous particles. This is followed by the detailed description of various methods used to fabricate core-shell particles. We then discuss the applications of common silica core-shell particles (mostly commercially manufactured), spheres-on-sphere particles and core-shell particles with a non-silica shell. This review concludes with a summary and perspective on the development of stationary phase materials for high-performance liquid chromatography applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Sexual selection on land snail shell ornamentation: a hypothesis that may explain shell diversity

    NARCIS (Netherlands)

    Schilthuizen, M.

    2003-01-01

    Background: Many groups of land snails show great interspecific diversity in shell ornamentation, which may include spines on the shell and flanges on the aperture. Such structures have been explained as camouflage or defence, but the possibility that they might be under sexual selection has not

  10. Four-loop on-shell integrals. MS-on-shell relation and g-2

    Energy Technology Data Exchange (ETDEWEB)

    Marquard, P.

    2013-12-15

    We present first results towards a full four-loop calculation for both the anomalous magnetic moment of the muon and the MS-on-shell relation. The calculation requires the detailed study of an up to now not considered class of diagrams, so-called on-shell diagrams, at four-loop order.

  11. Synthesis and characterization of noble metal–titania core–shell nanostructures with tunable shell thickness

    Directory of Open Access Journals (Sweden)

    Bartosz Bartosewicz

    2017-10-01

    Full Text Available Core–shell nanostructures have found applications in many fields, including surface enhanced spectroscopy, catalysis and solar cells. Titania-coated noble metal nanoparticles, which combine the surface plasmon resonance properties of the core and the photoactivity of the shell, have great potential for these applications. However, the controllable synthesis of such nanostructures remains a challenge due to the high reactivity of titania precursors. Hence, a simple titania coating method that would allow better control over the shell formation is desired. A sol–gel based titania coating method, which allows control over the shell thickness, was developed and applied to the synthesis of Ag@TiO2 and Au@TiO2 with various shell thicknesses. The morphology of the synthesized structures was investigated using scanning electron microscopy (SEM. Their sizes and shell thicknesses were determined using tunable resistive pulse sensing (TRPS technique. The optical properties of the synthesized structures were characterized using UV–vis spectroscopy. Ag@TiO2 and Au@TiO2 structures with shell thickness in the range of ≈40–70 nm and 90 nm, for the Ag and Au nanostructures respectively, were prepared using a method we developed and adapted, consisting of a change in the titania precursor concentration. The synthesized nanostructures exhibited significant absorption in the UV–vis range. The TRPS technique was shown to be a very useful tool for the characterization of metal–metal oxide core–shell nanostructures.

  12. CIRCUMSTELLAR SHELL FORMATION IN SYMBIOTIC RECURRENT NOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Kevin; Bildsten, Lars [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93106 (United States)

    2012-12-20

    We present models of spherically symmetric recurrent nova shells interacting with circumstellar material (CSM) in a symbiotic system composed of a red giant (RG) expelling a wind and a white dwarf accreting from this material. Recurrent nova eruptions periodically eject material at high velocities ({approx}> 10{sup 3} km s{sup -1}) into the RG wind profile, creating a decelerating shock wave as CSM is swept up. High CSM densities cause the shocked wind and ejecta to have very short cooling times of days to weeks. Thus, the late-time evolution of the shell is determined by momentum conservation instead of energy conservation. We compute and show evolutionary tracks of shell deceleration, as well as post-shock structure. After sweeping up all the RG wind, the shell coasts at a velocity {approx}100 km s{sup -1}, depending on system parameters. These velocities are similar to those measured in blueshifted CSM from the symbiotic nova RS Oph, as well as a few Type Ia supernovae that show evidence of CSM, such as 2006X, 2007le, and PTF 11kx. Supernovae occurring in such systems may not show CSM interaction until the inner nova shell gets hit by the supernova ejecta, days to months after the explosion.

  13. Thermoluminescence analysis of irradiated oyster shells

    International Nuclear Information System (INIS)

    Cruz-Zaragoza, E.; Marcazzó, J.; Della Monaca, S.; Boniglia, C.; Gargiulo, R.; Bortolin, E.

    2012-01-01

    This paper reports the thermoluminescence (TL) analysis performed on the oyster shells powder. TL response of 60 Co gamma-rays irradiated samples were studied in the range from 80 Gy to 8 kGy doses. TL signal of irradiated shell powder was higher as compared to the unirradiated control samples, which allowed to identify the irradiated oysters. Results show that the oyster shells have good TL properties and can be useful for the identification of irradiated seafood as well as for the evaluation of the treatment dose. - Highlights: ► TL properties of irradiated oyster shell powder were studied. ► The SEM analysis shows that several elements are present in oyster shell powder. ► Calcite is the main component in the samples and β-calcite is also present. ► Following the European Standard EN 1788, the irradiated oyster can be identified. ► Determination of absorbed dose is possible by performing a preheat treatment.

  14. Folding of non-Euclidean curved shells

    Science.gov (United States)

    Bende, Nakul; Evans, Arthur; Innes-Gold, Sarah; Marin, Luis; Cohen, Itai; Santangelo, Christian; Hayward, Ryan

    2015-03-01

    Origami-based folding of 2D sheets has been of recent interest for a variety of applications ranging from deployable structures to self-folding robots. Though folding of planar sheets follows well-established principles, folding of curved shells involves an added level of complexity due to the inherent influence of curvature on mechanics. In this study, we use principles from differential geometry and thin shell mechanics to establish fundamental rules that govern folding of prototypical creased shells. In particular, we show how the normal curvature of a crease line controls whether the deformation is smooth or discontinuous, and investigate the influence of shell thickness and boundary conditions. We show that snap-folding of shells provides a route to rapid actuation on time-scales dictated by the speed of sound. The simple geometric design principles developed can be applied at any length-scale, offering potential for bio-inspired soft actuators for tunable optics, microfluidics, and robotics. This work was funded by the National Science Foundation through EFRI ODISSEI-1240441 with additional support to S.I.-G. through the UMass MRSEC DMR-0820506 REU program.

  15. Open source integrated modeling environment Delta Shell

    Science.gov (United States)

    Donchyts, G.; Baart, F.; Jagers, B.; van Putten, H.

    2012-04-01

    In the last decade, integrated modelling has become a very popular topic in environmental modelling since it helps solving problems, which is difficult to model using a single model. However, managing complexity of integrated models and minimizing time required for their setup remains a challenging task. The integrated modelling environment Delta Shell simplifies this task. The software components of Delta Shell are easy to reuse separately from each other as well as a part of integrated environment that can run in a command-line or a graphical user interface mode. The most components of the Delta Shell are developed using C# programming language and include libraries used to define, save and visualize various scientific data structures as well as coupled model configurations. Here we present two examples showing how Delta Shell simplifies process of setting up integrated models from the end user and developer perspectives. The first example shows coupling of a rainfall-runoff, a river flow and a run-time control models. The second example shows how coastal morphological database integrates with the coastal morphological model (XBeach) and a custom nourishment designer. Delta Shell is also available as open-source software released under LGPL license and accessible via http://oss.deltares.nl.

  16. Thick or Thin Ice Shell on Europa?

    Science.gov (United States)

    2007-01-01

    Scientists are all but certain that Europa has an ocean underneath its icy surface, but they do not know how thick this ice might be. This artist concept illustrates two possible cut-away views through Europa's ice shell. In both, heat escapes, possibly volcanically, from Europa's rocky mantle and is carried upward by buoyant oceanic currents. If the heat from below is intense and the ice shell is thin enough (left), the ice shell can directly melt, causing what are called 'chaos' on Europa, regions of what appear to be broken, rotated and tilted ice blocks. On the other hand, if the ice shell is sufficiently thick (right), the less intense interior heat will be transferred to the warmer ice at the bottom of the shell, and additional heat is generated by tidal squeezing of the warmer ice. This warmer ice will slowly rise, flowing as glaciers do on Earth, and the slow but steady motion may also disrupt the extremely cold, brittle ice at the surface. Europa is no larger than Earth's moon, and its internal heating stems from its eccentric orbit about Jupiter, seen in the distance. As tides raised by Jupiter in Europa's ocean rise and fall, they may cause cracking, additional heating and even venting of water vapor into the airless sky above Europa's icy surface. (Artwork by Michael Carroll.)

  17. Double shell planar experiments on OMEGA

    Science.gov (United States)

    Dodd, E. S.; Merritt, E. C.; Palaniyappan, S.; Montgomery, D. S.; Daughton, W. S.; Schmidt, D. W.; Cardenas, T.; Wilson, D. C.; Loomis, E. N.; Batha, S. H.; Ping, Y.; Smalyuk, V. A.; Amendt, P. A.

    2017-10-01

    The double shell project is aimed at fielding neutron-producing capsules at the National Ignition Facility (NIF), in which an outer low-Z ablator collides with an inner high-Z shell to compress the fuel. However, understanding these targets experimentally can be challenging when compared with conventional single shell targets. Halfraum-driven planar targets at OMEGA are being used to study physics issues important to double shell implosions outside of a convergent geometry. Both VISAR and radiography through a tube have advantages over imaging through the hohlraum and double-shell capsule at NIF. A number physics issues are being studied with this platform that include 1-d and higher dimensional effects such as defect-driven hydrodynamic instabilities from engineering features. Additionally, the use of novel materials with controlled density gradients require study in easily diagnosed 1-d systems. This work ultimately feeds back into the NIF capsule platform through manufacturing tolerances set using data from OMEGA. Supported under the US DOE by the LANS, LLC under contract DE-AC52-06NA25396. LA-UR-17-25386.

  18. Multimode interaction in axially excited cylindrical shells

    Directory of Open Access Journals (Sweden)

    Silva F. M. A.

    2014-01-01

    Full Text Available Cylindrical shells exhibit a dense frequency spectrum, especially near the lowest frequency range. In addition, due to the circumferential symmetry, frequencies occur in pairs. So, in the vicinity of the lowest natural frequencies, several equal or nearly equal frequencies may occur, leading to a complex dynamic behavior. So, the aim of the present work is to investigate the dynamic behavior and stability of cylindrical shells under axial forcing with multiple equal or nearly equal natural frequencies. The shell is modelled using the Donnell nonlinear shallow shell theory and the discretized equations of motion are obtained by applying the Galerkin method. For this, a modal solution that takes into account the modal interaction among the relevant modes and the influence of their companion modes (modes with rotational symmetry, which satisfies the boundary and continuity conditions of the shell, is derived. Special attention is given to the 1:1:1:1 internal resonance (four interacting modes. Solving numerically the governing equations of motion and using several tools of nonlinear dynamics, a detailed parametric analysis is conducted to clarify the influence of the internal resonances on the bifurcations, stability boundaries, nonlinear vibration modes and basins of attraction of the structure.

  19. Inner shell ionization accompanying nuclear collisions

    International Nuclear Information System (INIS)

    Sujkowski, Z.

    1987-01-01

    Selected phenomena leading to inner shell ionization and being of relevance for nuclear physics are discussed. The selection emphasizes the K-shell ionization induced in head-on collisions by fast light and medium-heavy ions. Cross-sections are reviewed. Effects of multiple inner shell ionization on the K X-ray spectra are illustrated with recent results. Implications for nuclear experiments are noted. Use of atomic observables as clocks for proton induced nuclear reactions is reviewed. Prospects for H.I. reactions are discussed. Preliminary experimental results on the direct K-shell ionization accompanying H.I. fusion reactions are presented. The post-collisional K-shell ionization due to internal conversion of γ-rays is discussed as the dominating contribution to the ionization for residues of dissipative nuclear reactions with Z > 40. Systematics of the corresponding K X-ray multiplicities are presented for rotational nuclei. These multiplicity values can be used for determining cross-sections for e.g. incomplete fusion reactions. Examples of such applications are given. Also discussed is the use of target K X-rays for normalization purposes and of the post-collisional, residue K X-rays in the studies of high spin phenomena. 96 references, 35 figures, 3 tables

  20. SHELL DISEASES AND TOXINS REGULATED BY LAW

    Directory of Open Access Journals (Sweden)

    Natalija Topić Popović

    1999-06-01

    Full Text Available There is a long tradition of cultivating shells in Croatia, and the shell industry has a good perspective of further development. Since shells are delicate organisms that require special breeding conditions and climate, they are also subject to many diseases. Bonamiosis, haplospioridiosis, marteiliosis, microcytosis and perkinsosis are stated by the International Bureau for Epizootics as shell diseases that, in keeping with law, must be reported, and iridovirosis as a disease of a potential international importance. The same diseases are regulated by the Veterinary Law from 1997 as infectious diseases prevention of which is of an interest for the Republic of Croatia. Although, according to the law, it does not have to be prevented, in this article the disease Mytilicola is also described. According to the Health Department Statute from 1994, eatable part of shells are being tested for toxins of some marine dinoflagelates that can damage human health, and these are PSP (Paralytic Shellfish Poison, DSP (Diarrhoeic Shellfish Poison and NSP (Neuroparalytic Shellfish Poison.

  1. Spectrophotometry of the shell around AG Carinae

    Science.gov (United States)

    Mitra, P. Mila; Dufour, Reginald J.

    1990-01-01

    Spatially-resolved long-slit spectrophotometry are presented for two regions of the shell nebula around the P-Cygni variable star AG Carinae. The spectra cover the 3700-6800 A wavelength range. Emission-line diagnostics are used to derive extinction, electron temperatures, and densities for various positions in the nebula. The chemical abundances and ionization structure are calculated and compared with other types of planetary nebulae and shells around other luminous stars. It is found that the N/O and N/S ratios of Ag Car are high compared to solar neighborhood ISM values. The O/H depletion found for the AG Car shell approaches that found in the condensations of the Eta Car system.

  2. Anticavitation and Differential Growth in Elastic Shells

    KAUST Repository

    Moulton, Derek E.

    2010-07-22

    Elastic anticavitation is the phenomenon of a void in an elastic solid collapsing on itself. Under the action of mechanical loading alone typical materials do not admit anticavitation. We study the possibility of anticavitation as a consequence of an imposed differential growth. Working in the geometry of a spherical shell, we seek radial growth functions which cause the shell to deform to a solid sphere. It is shown, surprisingly, that most material models do not admit full anticavitation, even when infinite growth or resorption is imposed at the inner surface of the shell. However, void collapse can occur in a limiting sense when radial and circumferential growth are properly balanced. Growth functions which diverge or vanish at a point arise naturally in a cumulative growth process. © 2010 Springer Science+Business Media B.V.

  3. Double shell tanks emergency pumping plan

    International Nuclear Information System (INIS)

    Tangen, M.J.

    1994-01-01

    At the request of the Department of Energy (DOE), a formal plan for the emergency transfer of waste from a leaking double shell tank to a designated receiver tank has been developed. This plan is in response to the priority 2 safety issue ''Response to a leaking double-shell tank'' in the DOE Report to Congress, 1991. The plan includes the tanks in four of the east tank farms and one of the west farms. The background information and supporting calculations used for the creation of the emergency plan are discussed in this document. The scope of this document is all of the double shell tanks in the AN, AP, AW, AY, and SY farms. The transfer lines, flush pits, and valve pits involved in the transfer of waste between these farms are also included in the scope. Due to the storage of high heat waste, AZ farm is excluded at this time

  4. Shell model description of Ge isotopes

    International Nuclear Information System (INIS)

    Hirsch, J G; Srivastava, P C

    2012-01-01

    A shell model study of the low energy region of the spectra in Ge isotopes for 38 ≤ N ≤ 50 is presented, analyzing the excitation energies, quadrupole moments, B(E2) values and occupation numbers. The theoretical results have been compared with the available experimental data. The shell model calculations have been performed employing three different effective interactions and valence spaces. We have used two effective shell model interactions, JUN45 and jj44b, for the valence space f 5/2 pg 9/2 without truncation. To include the proton subshell f 7/2 in valence space we have employed the fpg effective interaction due to Sorlin et al., with 48 Ca as a core and a truncation in the number of excited particles.

  5. Pair shell model description of collective motions

    International Nuclear Information System (INIS)

    Chen Hsitseng; Feng Dahsuan

    1996-01-01

    The shell model in the pair basis has been reviewed with a case study of four particles in a spherical single-j shell. By analyzing the wave functions according to their pair components, the novel concept of the optimum pairs was developed which led to the proposal of a generalized pair mean-field method to solve the many-body problem. The salient feature of the method is its ability to handle within the framework of the spherical shell model a rotational system where the usual strong configuration mixing complexity is so simplified that it is now possible to obtain analytically the band head energies and the moments of inertia. We have also examined the effects of pair truncation on rotation and found the slow convergence of adding higher spin pairs. Finally, we found that when the SDI and Q .Q interactions are of equal strengths, the optimum pair approximation is still valid. (orig.)

  6. Complete Surface Mapping of ICF Shells

    International Nuclear Information System (INIS)

    Stephens, R.B.; Olson, D.; Huang, H.; Gibson, J.B.

    2004-01-01

    Inertial confinement fusion shells have previously been evaluated on the basis of microscopic examination for local defects and limited surface profiling to represent their average fluctuation power. Since defects are local, and don't always have visible edges, this approach both misses some important fluctuations and doesn't properly represent the spatially dependent surface fluctuation power. We have taken the first step toward correcting this problem by demonstrating the capability to completely map the surface of a NIF shell with the resolution to account for all modes. This allows complete accounting of all the surface fluctuations. In the future this capability could be used for valuable shells to generate a complete r(θ, φ) surface map for accurate 3-D modeling of a shot

  7. The geometry of on-shell diagrams

    Science.gov (United States)

    Franco, Sebastián; Galloni, Daniele; Mariotti, Alberto

    2014-08-01

    The fundamental role of on-shell diagrams in quantum field theory has been recently recognized. On-shell diagrams, or equivalently bipartite graphs, provide a natural bridge connecting gauge theory to powerful mathematical structures such as the Grassmannian. We perform a detailed investigation of the combinatorial and geometric objects associated to these graphs. We mainly focus on their relation to polytopes and toric geometry, the Grassmannian and its stratification. Our work extends the current understanding of these connections along several important fronts, most notably eliminating restrictions imposed by planarity, positivity, reducibility and edge removability. We illustrate our ideas with several explicit examples and introduce concrete methods that considerably simplify computations. We consider it highly likely that the structures unveiled in this article will arise in the on-shell study of scattering amplitudes beyond the planar limit. Our results can be conversely regarded as an expansion in the understanding of the Grassmannian in terms of bipartite graphs.

  8. COMPLETE SURFACE MAPPING OF ICF SHELLS

    International Nuclear Information System (INIS)

    STEPHENS, R.B.; OLSON, D.; HUANG, H.; GIBSON, J.B.

    2003-09-01

    OAK-B135 Inertial confinement fusion shells have previously been evaluated on the basis of microscopic examination for local defects and limited surface profiling to represent their average fluctuation power. Since defects are local, and don't always have visible edges, this approach both misses some important fluctuations and doesn't properly represent the spatially dependent surface fluctuation power. they have taken the first step toward correcting this problem by demonstrating the capability to completely map the surface of a NIF shell with the resolution to account for all modes. This allows complete accounting of all the surface fluctuations. In the future this capability could be used for valuable shells to generate a complete r(θ,ψ) surface map for accurate 3-D modeling of a shot

  9. Modeling of microencapsulated polymer shell solidification

    International Nuclear Information System (INIS)

    Boone, T.; Cheung, L.; Nelson, D.; Soane, D.; Wilemski, G.; Cook, R.

    1995-01-01

    A finite element transport model has been developed and implemented to complement experimental efforts to improve the quality of ICF target shells produced via controlled-mass microencapsulation. The model provides an efficient means to explore the effect of processing variables on the dynamics of shell dimensions, concentricity, and phase behavior. Comparisons with experiments showed that the model successfully predicts the evolution of wall thinning and core/wall density differences. The model was used to efficiently explore and identify initial wall compositions and processing temperatures which resulted in concentricity improvements from 65 to 99%. The evolution of trace amounts of water entering into the shell wall was also tracked in the simulations. Comparisons with phase envelope estimations from modified UNIFAP calculations suggest that the water content trajectory approaches the two-phase region where vacuole formation via microphase separation may occur

  10. Vibrational analysis of submerged cylindrical shells based on elastic foundations

    International Nuclear Information System (INIS)

    Shah, A.G.; Naeem, M.N.

    2014-01-01

    In this study a vibration analysis was performed of an isotropic cylindrical shell submerged in fluid, resting on Winkler and Pasternak elastic foundations for simply supported boundary condition. Love's thin shell theory was exploited for strain- and curvature- displacement relationship. Shell problem was solved by using wave propagation approach. Influence of fluid and Winkler as well as Pasternak elastic foundations were studied on the natural frequencies of submerged isotropic cylindrical shells. Results were validated by comparing with the existing results in literature. Vibration, Submerged cylindrical shell, Love's thin shell theory, Wave propagation method, Winkler and Pasternak foundations. (author)

  11. Triggered Snap-Through of Bistable Shells

    Science.gov (United States)

    Cai, Yijie; Huang, Shicheng; Trase, Ian; Hu, Nan; Chen, Zi

    Elastic bistable shells are common structures in nature and engineering, such as the lobes of the Venus flytrap or the surface of a toy jumping poppers. Despite their ubiquity, the parameters that control the bistability of such structures are not well understood. In this study, we explore how the geometrical features of radially symmetric elastic shells affect the shape and potential energy of a shell's stable states, and how to tune certain parameters in order to generate a snap-through transition from a convex semi-stable state to concave stable state. We fabricated a series of elastic shells with varying geometric parameters out of silicone rubber and measured the resulting potential energy in the semi-stable state. Finite element simulations were also conducted in order to determine the deformation and stress in the shells during snap-through. It was found that the energy of the semi-stable state is controlled by only two geometric parameters and a dimensionless ratio. We also noted two distinct transitions during snap-through, one between monostability and semi-bistability (the state a popper toy is in before it snaps-through and jumps), and a second transition between semi-bistability and true bistability. This work shows that it is possible to use a set of simple parameters to tailor the energy landscape of an elastic shell in order to generate complex trigger motions for their potential use in smart applications. Z.C. acknowledge support from Society in Science-Branco Weiss Fellowship, administered by ETH Zurich.

  12. Transport comparison of multiwall carbon nanotubes by contacting outer shell and all shells.

    Science.gov (United States)

    Luo, Qiang; Cui, A-Juan; Zhang, Yi-Guang; Lu, Chao; Jin, Ai-Zi; Yang, Hai-Fang; Gu, Chang-Zhi

    2010-11-01

    Carbon nanotubes, particularly multiwall carbon nanotubes (MWCNTs) can serve as interconnects in nanoelectronic devices and integrated circuits because of their extremely large current-carrying capacity. Many experimental results about the transport properties of individual MWCNTs by contacting outer shell or all shells have been reported. In this work, a compatible method with integrated circuit manufacturing process was presented to compare the transport property of an individual multiwall carbon nanotube (MWCNT) by contacting outer shell only and all shells successively. First of the Ti/Au electrodes contacting outer shell only were fabricated onto the nanotube through the sequence of electron beam lithography (EBL) patterning, metal deposition and lift-off process. After the characterization of its transport property, focused ion beam (FIB) was used to drill holes through the same nanotube at the as-deposited electrodes. Then new contact to the holes and electrodes were made by ion-induced deposition of tungsten from W(CO)6 precursor gas. The transport results indicated that the new contact to all shells can clear up the intershell resistance and the electrical conductance of the tube can be improved about 8 times compared to that of by contacting outer shell only.

  13. A refined element-based Lagrangian shell element for geometrically nonlinear analysis of shell structures

    Directory of Open Access Journals (Sweden)

    Woo-Young Jung

    2015-04-01

    Full Text Available For the solution of geometrically nonlinear analysis of plates and shells, the formulation of a nonlinear nine-node refined first-order shear deformable element-based Lagrangian shell element is presented. Natural co-ordinate-based higher order transverse shear strains are used in present shell element. Using the assumed natural strain method with proper interpolation functions, the present shell element generates neither membrane nor shear locking behavior even when full integration is used in the formulation. Furthermore, a refined first-order shear deformation theory for thin and thick shells, which results in parabolic through-thickness distribution of the transverse shear strains from the formulation based on the third-order shear deformation theory, is proposed. This formulation eliminates the need for shear correction factors in the first-order theory. To avoid difficulties resulting from large increments of the rotations, a scheme of attached reference system is used for the expression of rotations of shell normal. Numerical examples demonstrate that the present element behaves reasonably satisfactorily either for the linear or for geometrically nonlinear analysis of thin and thick plates and shells with large displacement but small strain. Especially, the nonlinear results of slit annular plates with various loads provided the benchmark to test the accuracy of related numerical solutions.

  14. About two new efficient nonlinear shell elements

    International Nuclear Information System (INIS)

    Yin, J.; Suo, X.Z.; Combescure, A.

    1989-01-01

    The aim of the paper is to present the development of two shell elements for non linear analysis. The first one is an axisymetric curved shell element and it is developed for buckling analysis. The formulation is given, as well as some typical applications. The second one is an extension of the classical DKT element to large strains taking into account all aspects of non linearities. This element is used for the simulation of four point bending of cracked pipes. The whole experiment is simulated by the calculation taking into account very large strains at the crack tip and propagation of the crack

  15. Forced vibrations of rotating circular cylindrical shells

    International Nuclear Information System (INIS)

    Igawa, Hirotaka; Maruyama, Yoshiyuki; Endo, Mitsuru

    1995-01-01

    Forced vibrations of rotating circular cylindrical shells are investigated. Basic equations, including the effect of initial stress due to rotation, are formulated by the finite-element method. The characteristic relations for finite elements are derived from the energy principle by considering the finite strain. The equations of motion can be separated into quasi-static and dynamic ones, i.e., the equations in the steady rotating state and those in the vibration state. Radial concentrated impulses are considered as the external dynamic force. The transient responses of circular cylindrical shells are numerically calculated under various boundary conditions and rotating speeds. (author)

  16. Linux command line and shell scripting bible

    CERN Document Server

    Blum, Richard

    2014-01-01

    Talk directly to your system for a faster workflow with automation capability Linux Command Line and Shell Scripting Bible is your essential Linux guide. With detailed instruction and abundant examples, this book teaches you how to bypass the graphical interface and communicate directly with your computer, saving time and expanding capability. This third edition incorporates thirty pages of new functional examples that are fully updated to align with the latest Linux features. Beginning with command line fundamentals, the book moves into shell scripting and shows you the practical application

  17. Nitride stabilized core/shell nanoparticles

    Science.gov (United States)

    Kuttiyiel, Kurian Abraham; Sasaki, Kotaro; Adzic, Radoslav R.

    2018-01-30

    Nitride stabilized metal nanoparticles and methods for their manufacture are disclosed. In one embodiment the metal nanoparticles have a continuous and nonporous noble metal shell with a nitride-stabilized non-noble metal core. The nitride-stabilized core provides a stabilizing effect under high oxidizing conditions suppressing the noble metal dissolution during potential cycling. The nitride stabilized nanoparticles may be fabricated by a process in which a core is coated with a shell layer that encapsulates the entire core. Introduction of nitrogen into the core by annealing produces metal nitride(s) that are less susceptible to dissolution during potential cycling under high oxidizing conditions.

  18. Shell Colour Polymorphism in Bulla ampulla

    DEFF Research Database (Denmark)

    Cedhagen, Tomas

    1999-01-01

    Colour patterns of Bulla ampulla shells collected from Africa eastward to Pacific Islands were studied. 1\\vo common colour morphs were found. The typical morph is commonest. It is closely and finely mottled or all over with pinkish-gray on a creamy or flesh~tinted ground, with darker clouds......, irregular, V-shaped, or as longitudinal bands. The colouration of the other common morph is more uniform. It is lacking the darker clouds or bands and the colour is more greyish. The entire shell surface is densely mottled all over with small brown spots on a grey or beige background. Both morphs seem...

  19. Electron induced atomic inner-shell ionization

    International Nuclear Information System (INIS)

    Quarles, C.A.

    1974-01-01

    The current status of cross section measurements for atomic inner-shell ionization by electron bombardment is reviewed. Inner shell ionization studies using electrons as projectiles compliment the similar studies being done with heavy particles, and in addition can provide tests of the theory in those cases when relativistic effects and exchange effects are expected to be important. Both total cross sections and recently measured differential cross sections will be discussed and compared with existing theories where possible. Prospects for further experimental and theoretical work in this area of atomic physics using small electron accelerators will also be discussed

  20. Theoretical spectroscopy and the fp shell

    International Nuclear Information System (INIS)

    Poves, A.; Zuker, A.

    1980-01-01

    The recently developed quasiconfiguration method is applied to fp shell nuclei. Second order degenerate perturbation theory is shown to be sufficient to produce, for low lying states, the same results as large diagonalizations in the f(7/2)p(3/2)p(1/2)f(5/2)sup(n) full space. due to the operation of linked cluster mechanisms. Realistic interactions with minimal monopole changes are shown to be successful in reproducing spectra, binding energies, quadrupole moments and transition rates. Large shell model spaces are seen to exhibit typical many body behaviour. Quasiconfigurations allow insight into the underlying coupling schemes

  1. Galileon radiation from a spherical collapsing shell

    Energy Technology Data Exchange (ETDEWEB)

    Martín-García, Javier [Instituto de Física Teórica UAM/CSIC,C/ Nicolás Cabrera 15, E-28049 Madrid (Spain); Vázquez-Mozo, Miguel Á. [Instituto Universitario de Física Fundamental y Matemáticas (IUFFyM),Universidad de Salamanca, Plaza de la Merced s/n, E-37008 Salamanca (Spain)

    2017-01-17

    Galileon radiation in the collapse of a thin spherical shell of matter is analyzed. In the framework of a cubic Galileon theory, we compute the field profile produced at large distances by a short collapse, finding that the radiated field has two peaks traveling ahead of light fronts. The total energy radiated during the collapse follows a power law scaling with the shell’s physical width and results from two competing effects: a Vainshtein suppression of the emission and an enhancement due to the thinness of the shell.

  2. Degree of Acetylization Chitosan Gonggong Snail Shells

    Science.gov (United States)

    Horiza, H.; Iskandar, I.; Aldo, N.

    2018-04-01

    Chitosan is a polysaccharide obtained from the deacetylation of chitin, which is generally derived from crustacean animal waste and animal skins other sea. One marine animals that have compounds that can be processed chitin chitosan is derived from the snail Gonggong marine waters of Riau Islands province. The purpose of this study was to determine the degree of chitosan from the shells of snails asetilisasi Gonggong. This research is an experimental research laboratory. The results of this study indicate that the degree of chitosan shell snail deasetilisasi Gonggong is 70.27%.

  3. Shell model calculations for exotic nuclei

    International Nuclear Information System (INIS)

    Brown, B.A.; Wildenthal, B.H.

    1991-01-01

    A review of the shell-model approach to understanding the properties of light exotic nuclei is given. Binding energies including p and p-sd model spaces and sd and sd-pf model spaces; cross-shell excitations around 32 Mg, including weak-coupling aspects and mechanisms for lowering the ntw excitations; beta decay properties of neutron-rich sd model, of p-sd and sd-pf model spaces, of proton-rich sd model space; coulomb break-up cross sections are discussed. (G.P.) 76 refs.; 12 figs

  4. Linux Command Line and Shell Scripting Bible

    CERN Document Server

    Blum, Richard

    2011-01-01

    The authoritative guide to Linux command line and shell scripting?completely updated and revised [it's not a guide to Linux as a whole ? just to scripting] The Linux command line allows you to type specific Linux commands directly to the system so that you can easily manipulate files and query system resources, thereby permitting you to automate commonly used functions and even schedule those programs to run automatically. This new edition is packed with new and revised content, reflecting the many changes to new Linux versions, including coverage of alternative shells to the default bash shel

  5. Influence of Shell Thickness on the Colloidal Stability of Magnetic Core-Shell Particle Suspensions.

    Science.gov (United States)

    Neville, Frances; Moreno-Atanasio, Roberto

    2018-01-01

    We present a Discrete Element study of the behavior of magnetic core-shell particles in which the properties of the core and the shell are explicitly defined. Particle cores were considered to be made of pure iron and thus possessed ferromagnetic properties, while particle shells were considered to be made of silica. Core sizes ranged between 0.5 and 4.0 μm with the actual particle size of the core-shell particles in the range between 0.6 and 21 μm. The magnetic cores were considered to have a magnetization of one tenth of the saturation magnetization of iron. This study aimed to understand how the thickness of the shell hinders the formation of particle chains. Chain formation was studied with different shell thicknesses and particle sizes in the presence and absence of an electrical double layer force in order to investigate the effect of surface charge density on the magnetic core-shell particle interactions. For core sizes of 0.5 and 4.0 μm the relative shell thicknesses needed to hinder the aggregation process were approximately 0.4 and 0.6 respectively, indicating that larger core sizes are detrimental to be used in applications in which no flocculation is needed. In addition, the presence of an electrical double layer, for values of surface charge density of less than 20 mC/m 2 , could stop the contact between particles without hindering their vertical alignment. Only when the shell thickness was considerably larger, was the electrical double layer able to contribute to the full disruption of the magnetic flocculation process.

  6. Development of Mortar Simulator with Shell-In-Shell System – Problem of External Ballistics

    Directory of Open Access Journals (Sweden)

    A. Fedaravicius

    2007-01-01

    Full Text Available The shell-in-shell system used in the mortar simulator raises a number of non-standard technical and computational problems starting from the requirement to distribute the propelling blast energy between the warhead and the ballistic barrel, finishing with the requirement that the length of warhead's flight path must be scaled to combat shell firing tables. The design problem of the simulator is split into two parts – the problem of external ballistics where the initial velocities of the warhead must be determined, and the problem of internal ballistics – where the design of the cartridge and the ballistic barrel must be performed.

  7. Interelectron correlations in photoionization of outer shells near inner shell thresholds

    International Nuclear Information System (INIS)

    Amusia, M Ya; Chernysheva, L V; Drukarev, E G

    2015-01-01

    We have studied the role of virtual excitations of inner shells upon outer shell photoionization. The calculations were performed in the frames of the Random Phase Approximation with Exchange (RPAE) and its generalized version GRPAE that take into account variation of the atomic field due to electron elimination and the inner vacancies decay. We apply both analytic approximation and numeric computations. The results are presented for 3p electrons in Ar and for 4d-electrons in Pd near inner shells thresholds. The effect considered proved to be quite noticeable. (paper)

  8. Theoretical assessment of a proposal for the simplified determination of critical loads of elastic shells

    International Nuclear Information System (INIS)

    Malmberg, T.

    1986-08-01

    Within the context of the stability analysis of the cryostat of a fusion reactor the question was raised whether or not the rather lengthy conventional stability analysis can be circumvented by applying a simplified strategy based on common linear Finite Element computer programs. This strategy involves the static linear deformation analysis of the structure with and without imperfections. For some simple stability problems this approach has been shown to be successful. The purpose of this study is to derive a general proof of the validity of this approach for thin shells with arbitrary geometry under hydrostatic pressure or dead loading along the boundary. This general assessment involves two types of analyses: 1) A general stability analysis for thin shells; this is based on a simple nonlinear shell theory and a stability criterion in form of the neutral (indifferent) equilibrium condition. This result is taken as reference solution. 2) A general linear deformation analysis for thin imperfect shells and the definition of a suitable scalar parameter (β-parameter) which should represent the reciprocal of the critical load factor. It is shown that the simplified strategy (=β-parameter approach'') generally is not capable to predict the actual critical load factor irrespective whether there is a hydrostatic pressure loading or dead loading along the edge of the shell. This general result is in contrast to the observations made for some simple stability problems. Nevertheless, the results of this study do not exclude the possibility that the simplified strategy will give reasonable approximate solutions at least for a restricted class of stability problems. (orig./HP) [de

  9. Effects of a Deep Mixed Shell on Solar g-Modes, p-Modes, and Neutrino Flux

    Science.gov (United States)

    Wolff, Charles L.

    2009-08-01

    A mixed-shell model that reflects g-modes away from the Sun's center is developed further by calibrating its parameters and evaluating a mixing mechanism: buoyancy. The shell roughly doubles g-mode oscillation periods and would explain why there is no definitive detection of their periods. But the shell has only minor effects on most p-modes. The model provides a mechanism for causing short-term fluctuations in neutrino flux and makes plausible the correlations between this flux and solar activity levels. Relations are derived for a shell heated asymmetrically by transient increases in nuclear burning in small "hot spots." The size of these spots and the timing of a heating event are governed by sets(ell) of standing asymptotic g-modes, coupled by a maximal principle that greatly enhances their excitation and concentrates power toward the equator, assisting the detection of higher-ell sets. Signals from all sets, except one, in the range 2 energy to mix the corresponding shell in a standard solar model in Lt107 yr.

  10. Generalized synthesis of mesoporous shells on zeolite crystals

    KAUST Repository

    Han, Yu; Pitukmanorom, Pemakorn; Zhao, L. J.; Ying, Jackie

    2010-01-01

    A simple and generalized synthetic approach is developed for creating mesoporous shells on zeolite crystals. This method allows for the tailoring of thickness, pore size, and composition of the mesoporous shell, and can be applied to zeolites

  11. Relativistic effects in atomic inner-shell transitions

    International Nuclear Information System (INIS)

    Chen, M.H.

    1982-01-01

    Theoretical calculations of atomic inner-shell transition rates based on independent-particle models are reviewed. Factors affecting inner-shell transition rates are examined, particularly the effects of relativity. 48 references, 5 figures

  12. Dense Medium Machine Processing Method for Palm Kernel/ Shell ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Cracked palm kernel is a mixture of kernels, broken shells, dusts and other impurities. In ... machine processing method using dense medium, a separator, a shell collector and a kernel .... efficiency, ease of maintenance and uniformity of.

  13. Problems with tunneling of thin shells from black holes

    Indian Academy of Sciences (India)

    Specifically for shells tunneling out of black holes, this quantity is not invariant under canonical transformations. ... Although such cases include alpha decay, they do not include the tunneling of shells from black holes. ... Current Issue : Vol.

  14. Biosorption of radionuclides by snail shell biomass

    International Nuclear Information System (INIS)

    Dhami, P.S.; Chaudhari, S.D.; Rathinam, M.; Gopalakrishnan, V.; Ramanujam, A.

    2001-01-01

    The sorption of various radionuclides from low acidic and alkaline medium was studied using biomass of snail shell origin. Quantitative removal of plutonium was achieved when an alkaline waste effluents of PUREX origin at pH 9.4 was treated using this biomass. The sorbed activity was recovered by dissolving it in 1.0 M nitric acid. (author)

  15. Structural experiments with ice (composite) shells

    NARCIS (Netherlands)

    Belis, J.; Martens, K.; Van Lancker, B.; Pronk, A.; Zingoni, Alphose

    2016-01-01

    ABSTRACT: Ice can be a very suitable building material for temporary structures in a freezing environment. When water, mixed with small fibre reinforcements, is sprayed onto an inflatable membrane structure in suitable cold outdoor conditions, a thin shell is formed which increases thickness layer

  16. Wellposedness of a cylindrical shell model

    International Nuclear Information System (INIS)

    McMillan, C.

    1994-01-01

    We consider a well-known model of a thin cylindrical shell with dissipative feedback controls on the boundary in the form of forces, shears, and moments. We show that the resulting closed loop feedback problem generates a s.c. semigroup of contractions in the energy space

  17. Membrane reinforcement in concrete shells: A review

    International Nuclear Information System (INIS)

    Gupta, A.K.

    1984-01-01

    A historical evolution of the membrane reinforcement design in concrete shells is presented. Theoretical developments, experimental verifications and the history of US codes and standards have been traced. For two decades now, the evidence is converging towards application of the principle of minimum resistance. This principle is rational, and it can reasonably explain the experimental results. (orig.)

  18. On Newton’s shell theorem

    Science.gov (United States)

    Borghi, Riccardo

    2014-03-01

    In the present letter, Newton’s theorem for the gravitational field outside a uniform spherical shell is considered. In particular, a purely geometric proof of proposition LXXI/theorem XXXI of Newton’s Principia, which is suitable for undergraduates and even skilled high-school students, is proposed. Minimal knowledge of elementary calculus and three-dimensional Euclidean geometry are required.

  19. Interface Fracture in Adhesively Bonded Shell Structures

    DEFF Research Database (Denmark)

    Jensen, Henrik Myhre

    2008-01-01

    Two methods for the prediction of crack propagation through the interface of adhesively bonded shells are discussed. One is based on a fracture mechanics approach; the other is based on a cohesive zone approach. Attention is focussed on predicting the shape of the crack front and the critical...

  20. Double-shell tank emergency pumping guide

    International Nuclear Information System (INIS)

    BROWN, M.H.

    1999-01-01

    This Double-Shell Tank Emergency Pumping Guide provides the preplanning necessary to expeditiously remove any waste that may leak from the primary tank to the secondary tank for Hanfords 28 DSTs. The strategy is described, applicable emergency procedures are referenced, and transfer routes and pumping equipment for each tank are identified

  1. Conceptual Design Tool for Concrete Shell Structures

    DEFF Research Database (Denmark)

    Holst, Malene Kirstine; Kirkegaard, Poul Henning

    2011-01-01

    This paper focuses on conceptual tools for concrete shell structures when working within the span of performance-based design and computational morphogenesis. The designer, referred to as the Architect-Engineer, works through several iterations parallel with aesthetic, functional and technical re...

  2. Double-shell tank emergency pumping guide

    International Nuclear Information System (INIS)

    BROWN, M.H.

    1999-01-01

    This Double-Shell Tank Emergency Pumping Guide provides the preplanning necessary to expeditiously remove any waste that may leak from the primary tank to the secondary tank for Hanford's 28 DSTS. The strategy is described, applicable emergency procedures are referenced, and transfer routes and pumping equipment for each tank are identified

  3. UHPFRC in large span shell structures

    NARCIS (Netherlands)

    Ter Maten, R.N.; Grunewald, S.; Walraven, J.C.

    2013-01-01

    Ultra-High Performance Fibre-Reinforced Concrete (UHPFRC) is an innovative concrete type with a high compressive strength and a far more durable character compared to conventional concrete. UHPFRC can be applied in structures with aesthetic appearance and high material efficiency. Shell structures

  4. Capillary micromechanics for core-shell particles

    NARCIS (Netherlands)

    Kong, T.; Wang, Liqiu; Wyss, H.M.; Shum, H.C.

    2014-01-01

    In this work, we have developed a facile, economical microfluidic approach as well as a simple model description to measure and predict the mechanical properties of composite core–shell microparticles made from materials with dramatically different elastic properties. By forcing the particles

  5. On the atomic shell structure calculation (1)

    International Nuclear Information System (INIS)

    Choe Sun Chol

    1986-01-01

    We have considered the problem of atomic shell structure calculation using operator technique. We introduce reduced matrix elements of annihilation operators according to eg. (4). The normalized basis function is denoted as || ...>. The reduced matrix elements of the pair annihilation operators are expressed throw one-electron matrix elements. Some numerical results are represented and the problem of sign assignment is discussed. (author)

  6. ESR dating of marine fossil shells

    International Nuclear Information System (INIS)

    Radtke, U.; Mangini, A.; Gruen, R.

    1985-01-01

    In order to establish the relatively new ESR dating method for marine shells a detailed comparison with the independent U-series technique was carried out. Agreement of both dating methods with the geological classification is strongly dependent on the species investigated and environmental conditions. Several problems encountered in the determination of the accumulated dose as well as the annual dose are discussed. (author)

  7. ESR dating of marine fossil shells

    Energy Technology Data Exchange (ETDEWEB)

    Radtke, U; Mangini, A; Gruen, R

    1985-01-01

    In order to establish the relatively new ESR dating method for marine shells a detailed comparison with the independent U-series technique was carried out. Agreement of both dating methods with the geological classification is strongly dependent on the species investigated and environmental conditions. Several problems encountered in the determination of the accumulated dose as well as the annual dose are discussed.

  8. Deutsche Shell AG. Annual report 1997

    International Nuclear Information System (INIS)

    1998-01-01

    This annual report of Deutsche Shell AG reflects its activities in the sector natural gas, mineral oil, chemicals and renewable energies. Environmental protection, safety at work, and the position of the group in society are further subjects. Financial data of 1997 are presented (balance sheet, profit-and-loss account,etc.). (orig./RHM) [de

  9. DNA nanoparticles with core-shell morphology.

    Science.gov (United States)

    Chandran, Preethi L; Dimitriadis, Emilios K; Lisziewicz, Julianna; Speransky, Vlad; Horkay, Ferenc

    2014-10-14

    Mannobiose-modified polyethylenimines (PEI) are used in gene therapy to generate nanoparticles of DNA that can be targeted to the antigen-presenting cells of the immune system. We report that the sugar modification alters the DNA organization within the nanoparticles from homogenous to shell-like packing. The depth-dependent packing of DNA within the nanoparticles was probed using AFM nano-indentation. Unmodified PEI-DNA nanoparticles display linear elastic properties and depth-independent mechanics, characteristic of homogenous materials. Mannobiose-modified nanoparticles, however, showed distinct force regimes that were dependent on indentation depth, with 'buckling'-like response that is reproducible and not due to particle failure. By comparison with theoretical studies of spherical shell mechanics, the structure of mannobiosylated particles was deduced to be a thin shell with wall thickness in the order of few nanometers, and a fluid-filled core. The shell-core structure is also consistent with observations of nanoparticle denting in altered solution conditions, with measurements of nanoparticle water content from AFM images, and with images of DNA distribution in Transmission Electron Microscopy.

  10. BOWOOSS: bionic optimized wood shells with sustainability

    Science.gov (United States)

    Pohl, Göran

    2011-04-01

    In architecture, shell construction is used for the most efficient, large spatial structures. Until now the use of wood rather played a marginal role, implementing those examples of architecture, although this material offers manifold advantages, especially against the background of accelerating shortage of resources and increasing requirements concerning the energy balance. Regarding the implementation of shells, nature offers a wide range of suggestions. The focus of the examinations is on the shells of marine plankton, especially of diatoms, whose richness in species promises the discovery of entirely new construction principles. The project is targeting at transferring advantageous features of these organisms on industrial produced, modular wood shell structures. Currently a transfer of these structures in CAD - models is taking place, helping to perform stress analysis by computational methods. Micro as well as macro structures are the subject of diverse consideration, allowing to draw the necessary conclusions for an architectural design. The insights of these tests are the basis for the development of physical models on different scales, which are used to verify the different approaches. Another important aim which is promoted in the project is to enhance the competitiveness of timber construction. Downsizing of the prefabricated structural elements leads to considerable lower transportation costs as abnormal loads can be avoided as far as possible and means of transportation can be loaded with higher efficiency so that an important contribution to the sustainability in the field of architecture can also be made.

  11. Hydrodynamic experiments on dacryoconarid shell telescoping

    Czech Academy of Sciences Publication Activity Database

    Hladil, Jindřich; Šimčík, Miroslav; Růžička, Marek; Kulaviak, Lukáš; Lisý, Pavel

    2014-01-01

    Roč. 47, č. 3 (2014), s. 376-396 ISSN 0024-1164 R&D Projects: GA ČR GAP210/10/2351 Institutional support: RVO:67985831 ; RVO:67985858 Keywords : dacryoconarid shells * experimental fluid mechanics * narrow cones * Palaeozoic * telescoping Subject RIV: DB - Geology ; Mineralogy; CI - Industrial Chemistry, Chemical Engineering (UCHP-M) Impact factor: 1.454, year: 2014

  12. Are Pericentric Inversions Reorganizing Wedge Shell Genomes?

    Directory of Open Access Journals (Sweden)

    Daniel García-Souto

    2017-12-01

    Full Text Available Wedge shells belonging to the Donacidae family are the dominant bivalves in exposed beaches in almost all areas of the world. Typically, two or more sympatric species of wedge shells differentially occupy intertidal, sublittoral, and offshore coastal waters in any given locality. A molecular cytogenetic analysis of two sympatric and closely related wedge shell species, Donax trunculus and Donax vittatus, was performed. Results showed that the karyotypes of these two species were both strikingly different and closely alike; whilst metacentric and submetacentric chromosome pairs were the main components of the karyotype of D. trunculus, 10–11 of the 19 chromosome pairs were telocentric in D. vittatus, most likely as a result of different pericentric inversions. GC-rich heterochromatic bands were present in both species. Furthermore, they showed coincidental 45S ribosomal RNA (rRNA, 5S rRNA and H3 histone gene clusters at conserved chromosomal locations, although D. trunculus had an additional 45S rDNA cluster. Intraspecific pericentric inversions were also detected in both D. trunculus and D. vittatus. The close genetic similarity of these two species together with the high degree of conservation of the 45S rRNA, 5S rRNA and H3 histone gene clusters, and GC-rich heterochromatic bands indicate that pericentric inversions contribute to the karyotype divergence in wedge shells.

  13. Rapid pasteurization of shell eggs using RF

    Science.gov (United States)

    A novel method for rapidly pasteurizing eggs in the shell could enhance the safety of the United States’ food supply. Current federal regulations do not require eggs sold in stores to be pasteurized, yet these eggs are often consumed raw or undercooked and cause untold cases of salmonella illness ea...

  14. 21 CFR 886.3800 - Scleral shell.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Scleral shell. 886.3800 Section 886.3800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... device made of glass or plastic that is intended to be inserted for short time periods over the cornea...

  15. Nucleon knockout: off-shell effects

    International Nuclear Information System (INIS)

    Stephenson, G.J. Jr.

    1977-01-01

    The effect of the off-energy-shell extrapolation of the proton-proton scattering amplitude on the analysis of (p,2p) reactions is discussed. In particular, the range of expected variations in this extrapolation is explored and the possibility of using knock-out reactions to limit models of the p-p amplitude is studied

  16. Magnetic core-shell silica particles

    NARCIS (Netherlands)

    Claesson, E.M.

    2007-01-01

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

  17. On-Shell Methods in Perturbative QCD

    International Nuclear Information System (INIS)

    Bern, Zvi; Dixon, Lance J.; Kosower, David A.

    2007-01-01

    We review on-shell methods for computing multi-parton scattering amplitudes in perturbative QCD, utilizing their unitarity and factorization properties. We focus on aspects which are useful for the construction of one-loop amplitudes needed for phenomenological studies at the Large Hadron Collider

  18. Elimination of threshold singularities in the relation between on-shell and pole widths

    International Nuclear Information System (INIS)

    Kniehl, B.A.; Palisoc, C.P.; Sirlin, A.

    2002-05-01

    In a previous communication by two of us, Phys. Rev. Lett. 81, 1373 (1998), the gauge-dependent deviations of the on-shell mass and total decay width from their gauge-independent pole counterparts were investigated at leading order for the Higgs boson of the Standard Model. In the case of the widths, the deviation was found to diverge at unphysical thresholds, m H =2√(ξ V )m V (V=W,Z), in the R ξ gauge. In this Brief Report, we demonstrate that these unphysical threshold singularities are properly eliminated if a recently proposed definition of wave-function renormalization for unstable particles is invoked. (orig.)

  19. Some general aspects of thin-shell wormholes with cylindrical symmetry

    International Nuclear Information System (INIS)

    Eiroa, Ernesto F.; Simeone, Claudio

    2010-01-01

    In this article we study a general class of nonrotating thin-shell wormholes with cylindrical symmetry. We consider two physically sound definitions of the flare-out condition and we show that the less restrictive one allows for the construction of wormholes with positive energy density at the throat. We also analyze the mechanical stability of these objects under perturbations preserving the symmetry, proving that previous results are particular cases of a general property. We present examples of wormholes corresponding to Einstein-Maxwell spacetimes.

  20. On the accuracy of the asymptotic theory for cylindrical shells

    DEFF Research Database (Denmark)

    Niordson, Frithiof; Niordson, Christian

    1999-01-01

    We study the accuracy of the lowest-order bending theory of shells, derived from an asymptotic expansion of the three-dimensional theory of elasticity, by comparing the results of this shell theory for a cylindrical shell with clamped ends with the results of a solution to the three......-dimensional problem. The results are also compared with those of some commonly used engineering shell theories....

  1. The dorsal shell wall structure of Mesozoic ammonoids

    Directory of Open Access Journals (Sweden)

    Gregor Radtke

    2017-03-01

    Full Text Available The study of pristine preserved shells of Mesozoic Ammonoidea shows different types of construction and formation of the dorsal shell wall. We observe three major types: (i The vast majority of Ammonoidea, usually planispirally coiled, has a prismatic reduced dorsal shell wall which consists of an outer organic component (e.g., wrinkle layer, which is the first layer to be formed, and the subsequently formed dorsal inner prismatic layer. The dorsal mantle tissue suppresses the formation of the outer prismatic layer and nacreous layer. With the exception of the outer organic component, secretion of a shell wall is omitted at the aperture. A prismatic reduced dorsal shell wall is always secreted immediately after the hatching during early teleoconch formation. Due to its broad distribution in (planispiral Ammonoidea, the prismatic reduced dorsal shell wall is probably the general state. (ii Some planispirally coiled Ammonoidea have a nacreous reduced dorsal shell wall which consists of three mineralized layers: two prismatic layers (primary and secondary dorsal inner prismatic layer and an enclosed nacreous layer (secondary dorsal nacreous layer. The dorsal shell wall is omitted at the aperture and was secreted in the rear living chamber. Its layers are a continuation of an umbilical shell doubling (reinforcement by additional shell layers that extends towards the ventral crest of the preceding whorl. The nacreous reduced dorsal shell wall is formed in the process of ontogeny following a prismatic reduced dorsal shell wall. (iii Heteromorph and some planispirally coiled taxa secrete a complete dorsal shell wall which forms a continuation of the ventral and lateral shell layers. It is formed during ontogeny following a prismatic reduced dorsal shell wall or a priori. The construction is identical with the ventral and lateral shell wall, including a dorsal nacreous layer. The wide distribution of the ability to form dorsal nacre indicates that it is

  2. TWO-DIMENSIONAL APPROXIMATION OF EIGENVALUE PROBLEMS IN SHELL THEORY: FLEXURAL SHELLS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The eigenvalue problem for a thin linearly elastic shell, of thickness 2e, clamped along its lateral surface is considered. Under the geometric assumption on the middle surface of the shell that the space of inextensional displacements is non-trivial, the authors obtain, as ε→0,the eigenvalue problem for the two-dimensional"flexural shell"model if the dimension of the space is infinite. If the space is finite dimensional, the limits of the eigenvalues could belong to the spectra of both flexural and membrane shells. The method consists of rescaling the variables and studying the problem over a fixed domain. The principal difficulty lies in obtaining suitable a priori estimates for the scaled eigenvalues.

  3. Optimised photocatalytic hydrogen production using core–shell AuPd promoters with controlled shell thickness

    DEFF Research Database (Denmark)

    Jones, Wilm; Su, Ren; Wells, Peter

    2014-01-01

    of these materials towards the reforming of alcohols for hydrogen production. The core–shell structured Au–Pd bimetallic nanoparticle supported on TiO2 has being of interest as it exhibited extremely high quantum efficiencies for hydrogen production. However, the effect of shell composition and thickness...... of the nanoparticles by a combination of X-ray absorption fine structure and X-ray photoelectron spectroscopy. Photocatalytic ethanol reforming showed that the core–shell structured Au–Pd promoters supported on TiO2 exhibit enhanced activity compared to that of monometallic Au and Pd as promoters, whilst the core......–shell Au–Pd promoters containing one ML equivalent Pd provide the optimum reactivity....

  4. Protein profiles of hatchery egg shell membrane.

    Science.gov (United States)

    Rath, N C; Liyanage, R; Makkar, S K; Lay, J O

    2016-01-01

    Eggshells which consist largely of calcareous outer shell and shell membranes, constitute a significant part of poultry hatchery waste. The shell membranes (ESM) not only contain proteins that originate from egg whites but also from the developing embryos and different contaminants of microbial and environmental origins. As feed supplements, during post hatch growth, the hatchery egg shell membranes (HESM) have shown potential for imparting resistance of chickens to endotoxin stress and exert positive health effects. Considering that these effects are mediated by the bioactive proteins and peptides present in the membrane, the objective of the study was to identify the protein profiles of hatchery eggshell membranes (HESM). Hatchery egg shell membranes were extracted with acidified methanol and a guanidine hydrochloride buffer then subjected to reduction/alkylation, and trypsin digestion. The methanol extract was additionally analyzed by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS). The tryptic digests were analyzed by liquid chromatography and tandem mass spectrometry (LC-MS-MS) to identify the proteins. Our results showed the presence of several proteins that are inherent and abundant in egg white such as, ovalbumin, ovotransferrin, ovocleidin-116, and lysozyme, and several proteins associated with cytoskeletal, cell signaling, antimicrobial, and catalytic functions involving carbohydrate, nucleic acid, and protein metabolisms. There were some blood derived proteins most likely originating from the embryos and several other proteins identified with different aerobic, anaerobic, gram positive, gram negative, soil, and marine bacterial species some commensals and others zoonotic. The variety of bioactive proteins, particularly the cell signaling and enzymatic proteins along with the diverse microbial proteins, make the HESM suitable for nutritional and biological application to improve post hatch immunity of poultry.

  5. Searching for nova shells around cataclysmic variables

    Science.gov (United States)

    Sahman, D. I.; Dhillon, V. S.; Knigge, C.; Marsh, T. R.

    2015-08-01

    We present the results of a search for nova shells around 101 cataclysmic variables (CVs), using H α images taken with the 4.2-m William Herschel Telescope (WHT) and the 2.5-m Isaac Newton Telescope Photometric H α Survey of the Northern Galactic Plane (IPHAS). Both telescopes are located on La Palma. We concentrated our WHT search on nova-like variables, whilst our IPHAS search covered all CVs in the IPHAS footprint. We found one shell out of the 24 nova-like variables we examined. The newly discovered shell is around V1315 Aql and has a radius of ˜2.5 arcmin, indicative of a nova eruption approximately 120 yr ago. This result is consistent with the idea that the high mass-transfer rate exhibited by nova-like variables is due to enhanced irradiation of the secondary by the hot white dwarf following a recent nova eruption. The implications of our observations for the lifetime of the nova-like variable phase are discussed. We also examined four asynchronous polars, but found no new shells around any of them, so we are unable to confirm that a recent nova eruption is the cause of the asynchronicity in the white dwarf spin. We find tentative evidence of a faint shell around the dwarf nova V1363 Cyg. In addition, we find evidence for a light echo around the nova V2275 Cyg, which erupted in 2001, indicative of an earlier nova eruption ˜300 yr ago, making V2275 Cyg a possible recurrent nova.

  6. Constraints for system specifications for the double-shell and single-shell tank systems

    Energy Technology Data Exchange (ETDEWEB)

    SHAW, C.P.

    1999-05-18

    This is a supporting document for the Level 1 Double-Shell and Single-Shell System Specifications. The rationale for selection of specific regulatory constraining documents cited in the two system specifications is provided. many of the regulations have been implemented by the Project Hanford Management Contract procedures (HNF-PROs) and as such noted and traced back to their origins in State and Federal regulations.

  7. Constraints for system specifications for the double-shell and single-shell tank systems

    International Nuclear Information System (INIS)

    SHAW, C.P.

    1999-01-01

    This is a supporting document for the Level 1 Double-Shell and Single-Shell System Specifications. The rationale for selection of specific regulatory constraining documents cited in the two system specifications is provided. many of the regulations have been implemented by the Project Hanford Management Contract procedures (HNF-PROs) and as such noted and traced back to their origins in State and Federal regulations

  8. Ionization of inner shells of atoms taking account of outer shell rearrangement

    International Nuclear Information System (INIS)

    Amusia, M.Ya.

    1977-01-01

    The application of the general many-body theory and methods formulated with its help, in particular, the so-called random phase approximation with exchange (RPAE) and the many-body perturbation theory (MBPT) makes possible a description of ionization processes for many outer and intermediate shells of a number of atoms. This investigation of outer- and intermediate-shell ionization by photons and electrons demonstrates the collective character of these processes and the possibility of describing them by RPAE. 28 references

  9. Shell report 2001; Les personnes, la planete, les profits. Shell rapport 2001

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    In 2001, Shell saw mixed results across the social, environmental and economic spectrum. In order to contribute to the sustainable development, the Group is on track towards meeting its target to reduce greenhouse gas emissions to 10 % below 1990 levels by the end of 2002, although there was a significant increase in spill volumes and greenhouse gas emissions rose. Shell has articulated the business case and defined seven principles of sustainable development for use across the Group in business plans and daily operations: generating robust profitability; delivering value to customers; protecting the environment; managing resources; respecting and safeguarding people; benefiting communities; and working with stakeholders. Key points from the Shell Report include: in the framework of Managing, an independent review of the Shell Nigeria Community Development programme and testing of a human rights assessment tool in Shell South Africa and the implementing of a new Diversity and Inclusiveness Standard; in the framework of the economy the cost improvements of 5,1 billion dollars, ahead of target, the second highest earnings ever in difficult market conditions and the election of Shell top brand for fifth year running by motorists; in the framework of the Social, the safety performance, the avoidance of 100 contracts for incompatibility with Shell Business Principles; in the framework of the Environment, the publication of the Fresh water usage report for the first time, the Greenhouse gas emissions, the increase of spills as a result of a small number of incidents including a pipeline rupture in Nigeria and a well blow out in Oman. The economic, environmental and social data of the Shell Report are externally verified. (A.L.B.)

  10. Vibrations of thin piezoelectric shallow shells: Two-dimensional ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    In this paper we consider the eigenvalue problem for piezoelectric shallow shells and we show that, as the thickness of the shell goes to zero, the eigensolutions of the three-dimensional piezoelectric shells converge to the eigensolutions of a two- dimensional eigenvalue problem. Keywords. Vibrations; piezoelectricity ...

  11. 46 CFR 174.225 - Hull penetrations and shell connections.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Hull penetrations and shell connections. 174.225 Section 174.225 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... § 174.225 Hull penetrations and shell connections. Each overboard discharge and shell connection except...

  12. Initial Single-Shell Tank Retrieval System mission analysis report

    International Nuclear Information System (INIS)

    Hertzel, J.S.

    1996-03-01

    This document provides the mission analysis for the Initial Single-Shell Tank Retrieval System task, which supports the Single-Shell Tank Waste Retrieval Program in its commitment to remove waste from single-shell tanks for treatment and final closure

  13. Optical properties of spherical and oblate spheroidal gold shell colloids

    NARCIS (Netherlands)

    Penninkhof, J.J.; Moroz, A.; van Blaaderen, A.; Polman, A.

    2008-01-01

    The surface plasmon modes of spherical and oblate spheroidal core−shell colloids composed of a 312 nm diameter silica core and a 20 nm thick Au shell are investigated. Large arrays of uniaxially aligned core−shell colloids with size aspect ratios ranging from 1.0 to 1.7 are fabricated using a novel

  14. Properties of Activated Carbon Prepared from Coconut Shells in ...

    African Journals Online (AJOL)

    Materials commonly used for preparation of activated carbons include coal and coconut shells. Ghana generates over 30,000 tonnes of coconut shells annually from coconut oil processing activities but apart from a small percentage of the shells, which is burned as fuel, the remaining is usually dumped as waste.

  15. From Bash to Z shell in 5 min

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    Chances are you're spending a good amount of your time working on a shell. While Bash is the standard shell on Linux, some alternatives exist. I'll show you how to switch to one of them (Z shell) and what benefits come with it.

  16. Porous Core-Shell Nanostructures for Catalytic Applications

    Science.gov (United States)

    Ewers, Trevor David

    Porous core-shell nanostructures have recently received much attention for their enhanced thermal stability. They show great potential in the field of catalysis, as reactant gases can diffuse in and out of the porous shell while the core particle is protected from sintering, a process in which particles coalesce to form larger particles. Sintering is a large problem in industry and is the primary cause of irreversible deactivation. Despite the obvious advantages of high thermal stability, porous core-shell nanoparticles can be developed to have additional interactive properties from the combination of the core and shell together, rather than just the core particle alone. This dissertation focuses on developing new porous core-shell systems in which both the core and shell take part in catalysis. Two types of systems are explored; (1) yolk-shell nanostructures with reducible oxide shells formed using the Kirkendall effect and (2) ceramic-based porous oxide shells formed using sol-gel chemistry. Of the Kirkendall-based systems, Au FexOy and Cu CoO were synthesized and studied for catalytic applications. Additionally, ZnO was explored as a potential shelling material. Sol-gel work focused on optimizing synthetic methods to allow for coating of small gold particles, which remains a challenge today. Mixed metal oxides were explored as a shelling material to make dual catalysts in which the product of a reaction on the core particle becomes a reactant within the shell.

  17. The status of experimental buckling investigations of shells

    International Nuclear Information System (INIS)

    Singer, J.

    1982-01-01

    The recent developments in shell buckling experiments are surveyed and related to a review of the progress in the seventies. Model fabrication, imperfection measurements, boundary conditions, nondestructive testing, combined loading, postbuckling behavior, composite shells and other aspects of shell buckling tests are discussed. The motivation for experiments and the conclusions drawn in the previous review are reassessed. (orig.)

  18. Ni3Si(Al)/a-SiOx core shell nanoparticles: characterization, shell formation, and stability

    Science.gov (United States)

    Pigozzi, G.; Mukherji, D.; Gilles, R.; Barbier, B.; Kostorz, G.

    2006-08-01

    We have used an electrochemical selective phase dissolution method to extract nanoprecipitates of the Ni3Si-type intermetallic phase from two-phase Ni-Si and Ni-Si-Al alloys by dissolving the matrix phase. The extracted nanoparticles are characterized by transmission electron microscopy, energy-dispersive x-ray spectrometry, x-ray powder diffraction, and electron powder diffraction. It is found that the Ni3Si-type nanoparticles have a core-shell structure. The core maintains the size, the shape, and the crystal structure of the precipitates that existed in the bulk alloys, while the shell is an amorphous phase, containing only Si and O (SiOx). The shell forms around the precipitates during the extraction process. After annealing the nanoparticles in nitrogen at 700 °C, the tridymite phase recrystallizes within the shell, which remains partially amorphous. In contrast, on annealing in air at 1000 °C, no changes in the composition or the structure of the nanoparticles occur. It is suggested that the shell forms after dealloying of the matrix phase, where Si atoms, the main constituents of the shell, migrate to the surface of the precipitates.

  19. Egg Shell and Oyster Shell Powder as Alternatives for Synthetic Phosphate: Effects on the Quality of Cooked Ground Pork Products.

    Science.gov (United States)

    Cho, Min Guk; Bae, Su Min; Jeong, Jong Youn

    2017-01-01

    This study aimed to determine the optimal ratio of natural calcium powders (oyster shell and egg shell calcium) as synthetic phosphate replacers in pork products. Ground pork samples were subjected to six treatments, as follows: control (-) (no phosphate added), control (+) (0.3% phosphate blend added), treatment 1 (0.5% oyster shell calcium powder added), treatment 2 (0.3% oyster shell calcium powder and 0.2% egg shell calcium powder added), treatment 3 (0.2% oyster shell calcium powder and 0.3% egg shell calcium powder added), and treatment 4 (0.5% egg shell calcium powder added). The addition of natural calcium powders resulted in an increase in the pH values of meat products, regardless of whether they were used individually or mixed. The highest cooking loss was observed ( p cooking loss in samples with natural calcium powder added was similar ( p >0.05) to that in the positive control samples. CIE L* values decreased as the amount of added egg shell calcium powder increased. CIE a* values were higher ( p egg shell powder (treatment 2 or 3) was effective for the improvement of textural properties of the pork products. The findings show that the combined use of 0.2% oyster shell calcium and 0.3% egg shell calcium should enable the replacement of synthetic phosphate in the production of cooked pork products with desirable qualities.

  20. Modeling plate shell structures using pyFormex

    DEFF Research Database (Denmark)

    Bagger, Anne; Verhegghe, Benedict; Hertz, Kristian Dahl

    2009-01-01

    A shell structure made of glass combines a light-weight structural concept with glass’ high permeability to light. If the geometry of the structure is plane-based facetted (plate shell structure), the glass elements will be plane panes, and these glass panes will comprise the primary load...... (plate shells and triangulated lattice shells) may not differ in complexity regarding the topology, but when it comes to the practical generation of the geometry, e.g. in CAD, the plate shell is far more troublesome to handle than the triangulated geometry. The free software tool “pyFormex”, developed...