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Articles de revues sur le sujet "Salt - free condition"
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Tang, Bing Tao, Wen Tao Wang, Jin Jing Qiu, Jian Huang et Shu Fen Zhang. « Synthesis and Performances of Crosslinking Polymeric Dyes ». Applied Mechanics and Materials 752-753 (avril 2015) : 90–97. http://dx.doi.org/10.4028/www.scientific.net/amm.752-753.90.
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Development of dyes with high fixation and salt-free dyeing process for cotton and silk is essential for the textile industry due to ecological and economical reasons. In this study, the synthesis of novel crosslinking polymeric dyes and its salt-free crosslinking dyeing method are described, and cotton and silk have been effectively dyed with the novel dyes. Excellent dye fixation of over 99% on silk and over 97% on cotton, were achieved in a padding process in the salt-free condition. The dyes showed excellent wet fastness values equal to those observed for the standard reactive dyeing.
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Delgado, A. V., S. Ahualli, F. J. Arroyo, M. L. Jiménez et F. Carrique. « Electrokinetic detection of the salt-free condition in colloids. Application to polystyrene latexes ». Advances in Colloid and Interface Science 299 (janvier 2022) : 102539. http://dx.doi.org/10.1016/j.cis.2021.102539.
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KAMBLE, NARENDRA R., et VINOD T. KAMBLE. « A Facile Solvent-Free Route for One-Pot Multicomponent Synthesis of Benzylpyrazolyl Coumarins Derivatives in Presence of Effective Synergetic Catalytic System ». Asian Journal of Chemistry 31, no 6 (29 avril 2019) : 1357–61. http://dx.doi.org/10.14233/ajchem.2019.21986.
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A combinatorial library of benzylpyrazolyl coumarin derivatives have been synthesized by a green one-pot four-component reaction between aryl hydrazine/hydrazine hydrate (1), ethyl acetoacetate (2), aromatic aldehydes (3) and 4-hydroxycoumarin (4) catalyzed by niobium pentachloride with silver salt under solvent-free conditions has been developed. Experimental simplicity, simple work-up procedure and solvent-free reaction condition at room temperature are important features of the present protocol.
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Kabir, Shekh Md Mamun. « Process maximization of salt free reactive dyeing on cotton using Taguchi approach ». BioResources 18, no 3 (15 mai 2023) : 4543–57. http://dx.doi.org/10.15376/biores.18.3.4543-4557.
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This study optimized the salt free reactive dyeing process using the Taguchi approach. Dyeing of cotton fabric with reactive dyes is popular because of its bright and brilliant color in various shade ranges. Cationization with ALBAFIX-WFF and the dyeing process on cotton fabric was carried out using the exhaust method. To determine the optimum process conditions, two types of multiple characteristic parameters, including the single characteristic value conversion method and the process maximization method, were used on the basis of color strength (K/S) and wash fastness. The single characteristic value conversion method confirmed that the optimum process condition was a cationization temperature of 40 °C and a dyeing pH of 11. Most importantly, the optimal conditions were confirmed by the process maximization method as a concentration of ALBAFIX-WFF 30 g/L, cationization temperature at 80 °C, dyeing pH 12, and material-to-liquor ratio (M:L) of 1:5. More suitable dyeing properties are also achieved by the process maximization method.
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Radman, Hanin M., Aasif A. Dabbawala, Issam Ismail, Yasser F. Alwahedi, Kyriaki Polychronopoulou, Balasubramanian V. Vaithilingam, Gnana P. Singaravel, Stephane Morin, Mikael Berthod et Saeed M. Alhassan. « Influence of salt on nanozeolite-Y particles size synthesized under organic template-free condition ». Microporous and Mesoporous Materials 282 (juillet 2019) : 73–81. http://dx.doi.org/10.1016/j.micromeso.2019.03.015.
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Chen, Ming. « Study on Electrogalvanizing Technology and Chromium-Free Passivation Treatment of 08Al Plate ». Journal of Physics : Conference Series 2168, no 1 (1 janvier 2022) : 012029. http://dx.doi.org/10.1088/1742-6596/2168/1/012029.
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Abstract An environment-friendly electrogalvanizing technology of 08Al cold rolled steel sheet (CRS) was developed. 08Al CRS sheet was placed as cathode in the electroplating solution containing zinc salt 1-10g/L, organic acid 3-24g/L, complexing agent 0.2-0.8g/L, and Hot-dip galvanized alloyed sheet (GA) as anode. The relationship between the current density and the plating mass per unit area was studied by applying 0.15-2A direct current at room temperature, current density 0.19-2.6A/dm2, and plating time 35min. The relationship between plating mass per unit area and anode thinning per unit area was linear regression by introducing current density as intermediate quantity. The effect of electric power range on the coating mass per unit area was studied under the condition of different concentration of main salt. The chromium-free passivation treatment was also carried out on the surface of electrogalvanizing layer. 08Al electrogalvanized sheet and GA sheet were placed in chromium-free passivation solution containing molybdate 1-10g/L, hydrogen peroxide 1-5g/L, fluorine ion complexing agent 1-10g/L, potassium hydroxide 1-2g/L. The temperature and reaction time of chromium-free passivation solution and the corrosion resistance of chemical conversion film were studied, and the experimental conditions of chromium-free passivation were optimized. The adhesion and corrosion resistance of the coating were tested by scratching test and neutral salt spray test (NSS). The results show that after scratching test, the adhesion of the electrogalvanizing layer on 08Al surface reaches grade 0, and the adhesion of the electrogalvanizing and chemical conversion film composite coating on 08Al surface reaches grade 0. The NSS test showed that the corrosion resistance increased with the increase of the thickness of the galvanizing layer. The corrosion resistance time of the galvanizing layer with the thickness of 15um exceeded 216h. Salt spray resistance time of electric galvanizing layer about 10um is 72-96 h; The salt spray resistance time of electrogalvanizing layer less than 5um is less than 48 h. The salt spray corrosion time of GA plate (galvanized layer thickness is 10-11um) is less than 96 h. After chromium-free passivation treatment, the corrosion resistance of GA plate is more than doubled to 192h. The salt spray corrosion resistance of the composite coating (10-11um thickness) on 08Al with electrogalvanizing and chemical conversion film can reach more than 216h.
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Rao, Deepak, Sangita Yadav, Ravish Choudhary, Dharmendra Singh, Rakesh Bhardwaj, Sharmistha Barthakur et Shiv Kumar Yadav. « Silicic and Humic Acid Priming Improves Micro- and Macronutrient Uptake, Salinity Stress Tolerance, Seed Quality, and Physio-Biochemical Parameters in Lentil (Lens culinaris spp. culinaris) ». Plants 12, no 20 (11 octobre 2023) : 3539. http://dx.doi.org/10.3390/plants12203539.
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Lentil is an important grain legume crop which is mostly grown on marginal soils that hamper its productivity. Improvement of salt tolerance in lentils is considered to be a useful strategy of utilizing salt-affected lands in an economic manner. This study was conducted to evaluate the effectiveness of seed priming using silicic acid and humic acid both seperately and in combination to improve salt stress tolerance among three different lentil varieties: IPL-316 (tolerant), PSL-9, and PDL-1 (susceptible). The concentrations and durations of treatments were standardized under the normal condition and the salinity stress condition. Salt stress hindered seedling emergence and biomass production and accelerated Na+ toxicity and oxidative damage at the seedling stage in untreated seeds. Nevertheless, chemical priming improved early seedling emergence, increased root length, shoot length, and seed vigor index I and II, and reduced the mean germination time. A significant quantitative change in biochemical parameters under normal and salinity stress conditions was observed in IPL-316,viz. Specifically, for IPL-316, the following parameters were observed (values under the normal condition and values under salt stress conditions, respectively): chlorophyll-a (16 and 13 mg/g Fw), chlorophyll-b (25 and 16 mg/g FW), total chlorophyll content (42 and 30 mg/g FW), relative leaf water content (92% and 82%), total soluble sugars (26 and 33 ug/g FW), free amino acid (10 and 7 mg/g FW), total phenol (26 and 24 mg of GAE/g FW), total protein (35 and 29 mg/g FW), carbohydrate (208 and 173 mg/g FW), superoxide dismutase (SOD) (29 and 35 unit/min./g FW), proline (0.28 and 0.32 u mol/g FW), catalase (CAT) (84 and 196 unit/mL/g FW), and peroxidase (POX) (217 and 738 unit/mL/g FW). Furthermore, histochemical analysis of H2O2 and O2−, micronutrients, and macronutrients also increased, while malondialdehyde (MDA) (0.31 and 0.47 nmol/mL FW) content decreased using silicic and humic acid priming under salt stress conditions. The combination of silicic and humic acids improved seedling growth and reduced oxidative damage in lentil plants under salt stress conditions. The combination of silicic and humic acid priming hastened seedling emergence, seed quality parameters, and biochemical parameters under salt stress over respective control. To the best of our knowledge, this is the first report of integrated chemical priming in lentils for salinity stress. In conclusion, chemical priming using a combination of silicic and humic acid performed better in terms of seed quality due to enhanced antioxidant machinery, better membrane stability and osmolyte protection, and enhanced nutrient uptake under salt stress conditions.
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Mukul Sinha, Kale Bala Nirmala. « Development and Sensory Evaluation of Quinoa Based Sweet and Salt cookies ». International Journal of Current Microbiology and Applied Sciences 10, no 10 (10 octobre 2021) : 267–76. http://dx.doi.org/10.20546/ijcmas.2021.1010.032.
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Gluten, a visco elastic protein present in the wheat causes damage to the small intestine and as a result the microvilli of the small intestine gets atrophed. This situation leads to abdominal discomfort and malaborption of many vital vitamins. This condition is called as Gluten Sensitivity or Celiac Disease, following a gluten free diet is most suitable treatment. Gluten free cereals can be used in diet, but they can’t replace wheat in bakery products. The present study was conducted to develop gluten free cookies with quinoa, a nutrient dense pseudocereal. Three different types of cookies using two different types of quinoa flour were prepared. Sensory evaluation and nutritive value of the cookies revealed that Quinoa cookies have excellent sensory attributes and also they are high in nutritive value. Among all cookies made corn flake cookies (C1) cookies are much more appreciated than cinnamon cookies (C2) and salt cookies (C3).
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Ran, Wuping, Yu Zhang, Ling Li, Xizhong Shen, Hailin Zhu et Yongbo Zhang. « Characterization of Bonding between Asphalt Concrete Layer under Water and Salt Erosion ». Materials 12, no 19 (20 septembre 2019) : 3055. http://dx.doi.org/10.3390/ma12193055.
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The contact state between layers of asphalt pavement not only has a significant effect on the mechanical response of road structure but is also the bottleneck of research on the mechanical behavior of pavement structure at present. In this paper, the effects and laws of different water–salt entry modes, salt solution concentrations, and temperatures coupling on the contact state between base and surface layers are studied by a 45° inclined shear test. The simulation and verification of each working condition are carried out by ABAQUS (Dassault, Paris, France) the friction coefficient between layers is reversed, and the actual contact state between layers is characterized in order to realize comprehensive evaluation and reasonable expression. The results show that different modes have different effects on contact characteristics. At the same temperature and concentration of the salt solution, bonding of water and salt erosion is the best, followed by direct erosion, with the worst being from bottom to top, and the interlayer bonding condition is weakened with increase in temperature. The relative accuracy of the software simulation and test analysis was as high as 92% and the friction coefficient of the water-free salt erosion test piece was found to be about 0.85 at 25 °C, while after the bottom-up erosion of the 14% salt solution the friction coefficient was found to be about 0.43, which indicates that the corrosion of the water–salt will have a great effect on the bonding condition between the structural layers of the road.
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Boddula, Rajender, et Palaniappan Srinivasan. « Emeraldine Base Form of Polyaniline Nanofibers as New, Economical, Green, and Efficient Catalyst for Synthesis of Z-Aldoximes ». Journal of Catalysts 2014 (6 février 2014) : 1–6. http://dx.doi.org/10.1155/2014/515428.
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A facile, clean, economical, efficient, and green process was developed for the preparation of Z-aldoximes at room temperature under solvent-free condition using emeraldine base form of polyaniline as novel catalyst. In this methodology, PANI base absorbed the by-product of HCl (polluting chemical) from hydroxylamine hydrochloride and converted to polyaniline-hydrochloride salt (PANI-HCl salt). This PANI-HCl salt could be easily recovered and used in new attempts without any purification in many areas such as catalyst, electrical and electronics applications meant for conducting polymers. As far as our knowledge is concerned, emeraldine base as catalyst in organic synthesis for the first time.
Thèses sur le sujet "Salt - free condition"
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Chakraborty, Gulmi. « Studies on the Aggregation characteristics of selected surfactants and surface active ionic liquids ». Thesis, University of North Bengal, 2017. http://ir.nbu.ac.in/handle/123456789/2620.
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Khetsha, Zenzile Peter. « The effect of potassium and water quality on the yield and oil quality of Rose Geranium (Pelargonium graveolens L.) ». Thesis, Bloemfontein : Central University of Technology, Free State, 2013. http://hdl.handle.net/11462/189.
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Thesis (M. Tech. (Agriculture)) -- Central University of Technology, Free state, 2014The main objective of the study was to determine the effect of different potassium concentrations and water quality (salt) compared with the current scientifically accepted potassium threshold level and standardised water quality on the yield, oil composition and leaf morphology of rose geranium (Pelargonium graveolens L.) when grown in different potting-bag sizes and root media under temperature controlled condition. To achieve this objective, two trials were conducted. The first experiment evaluated potassium concentrations at 1.3, 3.3, 5.3 and 7.3 mmol L-1 and potting-bag size of 5 and 10 L. Treatments were arranged in a randomised complete block design assigned in a split plot layout. The main plots consisted of potassium concentration and the pottingbag sizes were allocated to sub-plots. Plant height, potassium content, linalool, geraniol, geranyl formate and the citronellol to geraniol ratio (C:G) were affected by potassium. Plant height, number of branches, the branch to height ratio (B:H), foliar fresh mass (FFM) and oil yield were significantly increased when 5 L potting bags were used. Plant foliar mass was significantly increased by the interaction between 5.3 mmol K L-1 and 5 L potting bags. In the second experiment salt levels applied at 1.6, 2.4, 3.2 and 4.0 mS cm-1 and root media (sand and sawdust) were evaluated. A split plot experimental layout was also used in this trial, with the salt levels allocated to the main plots. The sub-plots were allocated to the root medium. High salt level of 4.0 mS cm-1 reduced the number of leaves, plant height, number of branches, B:H ratio, leaf area, chlorophyll content and foliar fresh mass significantly. The number of leaves, leaf area and FFM were significantly increased where sawdust was used. Time of the day significantly affected stomatal conductance, and the opening of most stomata occurred at 10:00. Geranyl formate and the C:G ratio were significantly affected by salt at 4.0 mS cm-1. Salt induced the development of capitates trichomes. The abaxial leaf surface had a higher number of trichomes than the adaxial leaf surface. A strong polynomial (r2=0.97) relationship was found between capitates trichomes and salt levels. High densities of capitates trichomes were found at high salt level of 4.0 mS cm-1. Although the development of asciiform trichomes was induced, it was at an insignificant level. Trichome densities are therefore not affected by salt. It was therefore concluded that the application of 5.3 mmol K L-1 concentration and the use of 5 L potting bags improves the yield and oil quality of rose geranium. It was evident from this study that rose geranium might Salt induced have some degree of tolerance to salt. It was therefore concluded that rose geranium is a moderately salt-sensitive crop.
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Liao, Yen-Sen, et 廖彥森. « (1)One-pot Synthesis of Thioesters with Bunte Salts as a Sulfur Surrogate under Transition Metal-Free Conditions(2)Hexamethyldisilazane Promoted C-N Bond Formation via Thioesters : Synthesis of Benzamides and Dimethylformamidines ». Thesis, 2018. http://ndltd.ncl.edu.tw/handle/2am6n9.
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碩士國立中興大學
化學系所
106
In the first part of this thesis, we reported a convenient method of one-pot synthesis of thioesters by using odorless sodium thiosulfate, various anhydrides and organic halides. Compared with traditional method, this method did not use thiols, which possessed malodorous flavors and easily oxidized to form the disulfide bond. This synthetic method was firstly using organic anhydrides and sodium thiosulfate to form the Bunte salts, followed by reacting with organic halides to generate thioesters. Furthermore, two important organic compounds could be successfully synthesized using the developed method. It was worth to mention that our system was transition metal-free conditions and easy applicability to the large-scale operation. In the second part of this thesis, we developed a new method for the synthesis of primary amides by using thioesters and hexamethyldisilazane (HMDS). Compared with reported literatures, the developed methods were performed under metal-free conditions. In our synthetic strategy, we found that the hexamethyldisilazane in N,N-dimethylformamide (DMF) under heating conditions will be formed amidine, then reacted with thioesters to form the primary amide and dimethylformamidine. Moreover, primary amide and dimethylformamidine can be synthesized individually by adjusting the amounts of hexamethyldisilazane. In addition, we designed the control experiment to prove the formation of amidine by proton (H) and carbon-13 NMR spectrums. The advantages of this synthetic method were structurally diverse products, use of relatively cheap reagents, and easy applicability to large-scale operation.
Livres sur le sujet "Salt - free condition"
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Polin, Bonnie Sanders. Cleveland Clinic Healthy Heart Lifestyle Guide and Cookbook. New York : Broadway Books, 2008.
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Polin, Bonnie Sanders. Cleveland clinic healthy heart lifestyle guide and cookbook. New York : Broadway Books, 2007.
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In chancery, McCarthy vs. McCarthy : The following are the conditions of sale, the premises will be sold free from dower .. [London, Ont. ? : s.n., 1986.
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Hockenberry, Matthew, Nicole Starosielski et Susan Zieger, dir. Assembly Codes. Duke University Press, 2021. http://dx.doi.org/10.1215/9781478013037.
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The contributors to Assembly Codes examine how media and logistics set the conditions for the circulation of information and culture. They document how logistics—the techniques of organizing and coordinating the movement of materials, bodies, and information—has substantially impacted the production, distribution, and consumption of media. At the same time, physical media, such as paperwork, along with media technologies ranging from phone systems to software are central to the operations of logistics. The contributors interrogate topics ranging from the logistics of film production and the construction of internet infrastructure to the environmental impact of the creation, distribution, and sale of vinyl records. They also reveal how logistical technologies have generated new aesthetic and performative practices. In charting the specific points of contact, dependence, and friction between media and logistics, Assembly Codes demonstrates that media and logistics are co-constitutive and that one cannot be understood apart from the other. Contributors Ebony Coletu, Kay Dickinson, Stefano Harney, Matthew Hockenberry, Tung-Hui Hu, Shannon Mattern, Fred Moten, Michael Palm, Ned Rossiter, Nicole Starosielski, Liam Cole Young, Susan Zieger
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Wright, Tom F. Introduction. Oxford University Press, 2017. http://dx.doi.org/10.1093/acprof:oso/9780190496791.003.0001.
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This chapter introduces the popular lecture as a paradoxical icon of nineteenth-century modernity. On both sides of the Atlantic, it argues, the audiences and performers transformed a cultural practice with origins in the medieval cloister into an unexpected flashpoint medium of public life. It was an educational form that began to flourish amid the educational fervor of the late Scottish Enlightenment. But it bursts into life most powerfully in the United States in the decades leading up to the Civil War, where it was often known as the “lyceum movement.” As it grew, this phenomenon sat at the confluence of at least three major transformations in American life. First, it helped shape a revolution in oratory, fashioning a space for educational speech and rational debate that promised to float free of creed or party. Second, it embodied new ideals of republican education, democratizing the habits of elite collegiate pedagogy for the masses, and forging new economies of knowledge and cultural consumption. Third, it set in motion a lasting transformation in the relationship between the public and American literature, providing both the necessary conditions for the modern public intellectual and a powerful new performative conception of authorship. The introduction sets out the content for the chapters that follow.
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Free Homesteads of Wheat & Grazing Land in the Temperance Colony [microform] : Land for Sale, with or Without Conditions of Cultivation : Rare Inducements Offered to Emigrants from Great Britain : Freehold Farms May Be Acquired on Easy Terms. Creative Media Partners, LLC, 2021.
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Giedt, Frances Towner, Cleveland Clinic Heart Center et Bonnie Sanders Phd Polin. Cleveland Clinic Healthy Heart Lifestyle Guide and Cookbook : Featuring more than 150 tempting recipes. Broadway, 2007.
Trouver le texte intégralChapitres de livres sur le sujet "Salt - free condition"
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Kamen, Deborah. « Freedmen with Conditional Freedom ». Dans Status in Classical Athens. Princeton University Press, 2013. http://dx.doi.org/10.23943/princeton/9780691138138.003.0004.
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This chapter focuses on one of the two major subtypes of freed slave in classical Athens, the slaves freed with strings attached. It begins with a discussion of how manumission worked in classical Athens. Slaves in Athens could be freed in a number of different ways. Sometimes a master freed his own slaves. Slaves could also be freed through “purchase” by a third party. A large number of slaves were freed conditionally. The most striking feature of conditional-freedom manumission inscriptions is a so-called paramonē clause, mandating that the freedman remain and serve his or her former master. The paramonē clause also often includes sanctions, whether bodily punishment, sale, or invalidation of manumission, in the case of failure to perform paramonē service.
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Orwoll, Robert A., et Yong S. Chong. « Polyacrylamide ». Dans Polymer Data Handbook, 329–34. Oxford University PressNew York, NY, 2009. http://dx.doi.org/10.1093/oso/9780195181012.003.0052.
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Abstract Major Applications Flocculants in water treatment, paper manufacture, mining, and oil recovery; absorbents; gels for electrophoresis; thickening and binding agents; lubrication. Properties of Special Interest Amorphous. High affinity for water and completely miscible in water. Low toxicity. Low cost. Very high molecular weights attainable. Polymerization Conditions Most commonly, free-radical polymerizations of acrylamide in aqueous or aqueous salt solutions; but also precipitation polymerization in organic solvents; and emulsion polymerizations.
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Suzuki, Keiiciiiro. « Cell culture model for oxidative stress ». Dans Experimental protocols for reactive oxygen and nitrogen species, 287–88. Oxford University PressOxford, 2000. http://dx.doi.org/10.1093/oso/9780198506683.003.0081.
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Abstract Cells in culture are widely used as experimental models to study pro-oxidant and antioxidant responses. Although the conditions used are usually simple, and the results are obtained easily and rapidly, proteins, e.g. foetal calf serum, can act as radical scavengers, and iron and copper salts can also contaminate culture media during free-radical experiments. Appropriate controls must therefore be included and conditions carefully standardized, for example by using foetal calf serum (FCS)-free media.
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Savitz, A. J., et D. I. Meyer. « Ribosome receptor ». Dans Secretory Pathway, 72–73. Oxford University PressOxford, 1994. http://dx.doi.org/10.1093/oso/9780198599425.003.0043.
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Abstract The interaction of ribosomes with the membrane of the endoplasmic reticulum (ER) has been shown to be sensitive to puromycin and high salt1-4 as well as proteases1,5. This implies that protein-protein interactions, beyond that of the nascent chain with the translocation machinery, mediate ribosome binding. Rough microsomes, from which ribosomes have been removed (stripped), are able to rebind ribosomes, under the appropriate conditions, to pre-stripped levels5-7. To measure this rebinding, radiolabeled ribosomes are added to stripped membranes, and bound ribosomes are separated from free ribosomes by flotation of the membranes in a sucrose gradient7 In this way, the rebinding reaction can be quantified and characterized.
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Doraiswamy, L. K. « Bioorganic Synthesis Engineering ». Dans Organic Synthesis Engineering. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780195096897.003.0029.
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Biological processes, from the simplest to the most complex, can broadly be classified as those caused by the catalytic action of living entities known as microorganisms or microbes, and those promoted and catalyzed by “lifeless substances” produced by microorganisms, known as enzymes. The two together are often referred to as biocatalysts. The microbial kingdom of living entities consists of all living things with a very simple biological organization. Both microbes and enzymes can be used to promote or selectively achieve a wide range of chemical transformations. Indeed, biocatalysts occupy a unique position in the wide spectrum of catalysts used in organic technology and synthesis. One of the chief beneficiaries of the rising emphasis on environmentally friendly processes is the enzyme, for it is being increasingly pressed into service to generate technologies that are both highly selective and pollution free. As catalysts, enzymes accelerate the rates of reactions at milder conditions, are highly selective, are biodegradable, and can be used in “free” solution form or as immobilized heterogeneous catalysts. The last feature, their use in immobilized form, has been a major factor in the movement of the enzyme from laboratory to industry. Two main shortcomings of the conventional enzyme that have limited its application in organic synthesis are its restriction to reactions in the aqueous phase and to very mild temperatures and pressures. Research in the last few years has “released” the enzyme from these restrictions (see Govardhan and Margolin, 1995; Adams et al., 1995). Thus now it is possible to use enzymes in aqueous solutions containing water-miscible organic cosolvents, aqueous organic biphasic mixtures, and anhydrous organic solvents. Research has also uncovered microorganisms from a variety of unconventional habitats such as the biosphere and the depths of the oceans that have the unique ability to accomplish chemical transformations at extreme conditions covering a wide range of temperatures, pressures, and salt concentrations. Hence it seems almost certain that enzymes will play an increasingly important role in industrial organic synthesis.
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Taber, Douglass. « Developments in Alkene and Alkyne Metathesis ». Dans Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0025.
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Jon D. Rainier of the University of Utah has put forward (J. Am. Chem. Soc. 2007 , 129 , 12604) an elegant alternative to Ru-catalyzed alkene metathesis, demonstrating that an ω-alkenyl ester such as 1 will cyclize to the enol ether 2 under Tebbe conditions. The particular reactivity of free alcohols in Ru-catalyzed alkene metathesis is underscored by the observation (Tetrahedron Lett. 2007, 48, 6905) by Javed Iqbal of Dr. Reddy’s Laboratories, Ltd., Miyapur that attempted metathesis of the ether 4a failed, but metathesis of the diol 4b proceeded efficiently. Kazunori Koide of the University of Pittsburgh has demonstrated (Organic Lett. 2007, 9, 5235) that the yields of cross-metathesis with an alkenyl alcohol could be enhanced by binding it to a trityl resin. He observed that the Grela catalyst 8 was particularly effective in this application. Residual Ru species do not interfere with some subsequent transformations. Rodrigo B. Andrade of Temple University has demonstrated (Tetrahedron Lett. 2007, 48, 5367) that metathesis with an α, β-unsaturated aldehyde such as 11 can be followed directly by phosphonate condensation to give the doubly-homologated product 12. Philip J. Parsons of the University of Sussex has found (Organic Lett. 2007, 9, 2613) that the nitro functional group is compatible with the Ru catalyst. The product nitro alkene 15 could be cyclized (intramolecular Michael addition) to the cyclopentane 16, or (intramolecular dipolar cycloaddition) to the cyclopentane 17. There has been much interest in carrying out the several alkene metathesis transformations (cross metathesis, ring closing metathesis, ring-opening metathesis polymerization) in water. Robert H. Grubbs of the California Institute of Technology has designed (Angew. Chem. Int. Ed. 2007, 46, 5152) the ammonium salt 18 for this purpose, and Karol Grela of the Polish Academy of Sciences in Warsaw and Marc Mauduit of ENSC Rennes have jointly(Chem. Commun. 2007, 3771) put forward the pyridinium salt 19. Remarkably, Ronald T. Raines of the University of Wisconsin has shown (Organic Lett. 2007, 9, 4885) that the Hoveyda catalyst 20 is sufficiently stable in aqueous acetone and aqueous DME to function efficiently.
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Gadman, Leslie. « Knowledge Creation in Commitment-Based Value Networks in Multinational Organizations ». Dans Strategic Knowledge Management in Multinational Organizations, 28–39. IGI Global, 2008. http://dx.doi.org/10.4018/978-1-59904-630-3.ch002.
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The digital networked economy has gone global and is reshaping traditional business models. “Free” and “open source” software (Raymond, 1999) along with more recent successes in the private, public and social sectors offer a vision of a radically new globally networked economy. This economy is characterized by new sources of value creation and competition as barriers to entry are lowered and substitution made easier. It also requires a more stratified, localized approach to the marketplace (Hart and Milstein, 2003) to meet more specialized demands from customers and the societies and environments within which they live. These challenges have implications for almost every aspect of a firm’s strategy and business model, especially its ability to leverage these networks to create value through innovation. Yet, most multinational firms are ill – equipped to take advantage of the knowledge creation derived from high value relationships with suppliers, complementors and customers. This chapter shows the importance of developing a corporate strategy which takes into account ways in which an innovation focus must integrate with installed business processes. This chapter considers the challenges associated with knowledge disclosure, diffusion and utilization (Snowdon, 2002; Spinosa, Flores and Dreyfus, 2001) across value networks and concludes that while successful examples exist in “Free” and “open source” software projects (Raymond, 1999) commercialization of innovation becomes more challenging when increasing levels of personal and financial commitment are required (Mauer, Rai and Sali, 2004). Choosing the most appropriate value networking strategy can have serious implications for success. This chapter adds to studies on knowledge creation and knowledge transfer in multinational corporations by proposing a conceptual model of commitment based value networking strategy. It is hoped this will contribute to future research by offering a theoretical foundation upon which this research may be based and explains why and under what conditions people in commitment based value networks share knowledge.
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Taber, Douglass F. « Organic Functional Group Protection ». Dans Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0012.
Texte intégralRésumé :
Masato Kitamura of Nagoya University investigated (Chemistry Lett. 2009, 38, 188) the Ru-mediated deprotection of allyl ethers such as 1. The same catalyst was effective for the preparation of allyl ethers from the alcohol 2 and allyl alcohol. István E. Markó of the Université Catholique de Louvain showed (Organic Lett. 2009, 11, 2752) that SmI2 effected the reductive cleavage of an aryl ester 3, liberating the alcohol 4. Osamu Onomura of Nagasaki University found (Tetrahedron Lett. 2009, 50, 1466) that catalytic CuCl2 mediated the selective monoallylation of symmetrical diols such as 5. Péter Fügedi of the Hungarian Academy of Sciences, Budapest, observed (Tetrahedron Lett. 2009, 50, 2914) that TMSOTf catalyzed the selective reduction of 7 to the benzyl ether. BH3. NMe2 delivered the opposite regioisomer. Direct amination of an ester has been a long-sought transformation. Vladimir B. Birman of Washington University found (Organic Lett. 2009, 11, 1499) that 1,2,4-triazole 11 in combination with DBU was an effective catalyst for this reaction. Unactivated esters required higher reaction temperatures. Deprotection of amides often requires vigorous conditions, and the product free amines can be challenging to handle. Stefan G. Koenig of Sepracor Chemical Process devised (Organic Lett. 2009, 11, 433) a simple protocol for in situ formation and hydrolysis of the imidoyl chloride from 12 that delivered the amine hydrochloride 13 directly. Remarkably, benzamides are stable under these conditions. Hongmei Li of Merck Process devised (Tetrahedron Lett. 2009, 50, 1010) a related procedure: heating the more reactive trifluoroacetamide 14 with stoichiometric p-toluenesulfonic acid, and isolating the product as the p-toluenesulfonate salt 15. There has been a reluctance to use sulfonamide protecting groups, as they have been thought to be difficult to remove. Göran Hilmersson of the University of Gothenburg established (Organic Lett. 2009, 11, 503) that SmI2 instantaneously deprotected 16. Daniel E. Falvey of the University of Maryland designed (J. Org. Chem. 2009, 74, 3894) the benzyl ester 17, which was readily released under photolysis. Stanislaw Krompiec of the University of Silesia described (Tetrahedron Lett. 2009, 50, 1193) what appears to be a general strategy for the preparation of ortho esters such as 21.
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Taber, Douglass F. « The Thomson Synthesis of (–)-GB17 ». Dans Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.003.0096.
Texte intégralRésumé :
(–)-GB17 3 is one of the Galbulimima alkaloids, a family that shows a wide range of interesting physiological activity. Regan J. Thomson of Northwestern University devised (Angew. Chem. Int. Ed. 2012, 51, 2481) a convergent assembly of 3, a key step of which was the intramolecular Michael cyclization of 1 to 2. The hydroxy aldehyde 6 was prepared by alkylation of the dithiane 4 with 5, followed by hydrolysis. The preparation of 9, by condensation of 8 with 7 followed by hydrogenation and protection, had been reported by Lhommet. Condensation of 9 with the linchpin reagent 10 gave an intermediate keto phosphonate, which was combined with 6 to give, after oxidation, the aldehyde 1. Two new stereogenic centers are created in the course of the cyclization of 1. The authors found that the TFA salt 11 of the Hayashi catalyst delivered 2 with high diastereocontrol. Control experiments showed that the buttressing effect of the dithiane was required for the cyclization. The authors then explored the next intramolecular Michael cyclization of 13 to 14. In this cyclization, the stereogenic center at 6 is in jeopardy by elimination and readdition. Cyclization of the trans unsaturated ester led to the wrong diastereomer of 14, but cyclization of the cis ester 13, prepared by the Still-Gennari protocol, cleanly gave the desired diastereomer. The reaction worked best with the free amine. Under the conditions of the reaction the Michael addition product spontaneously cyclized to the lactam 14. The ketone of 14 was selectively enolized, then converted to its enol triflate, which under Pd-mediated reduction gave the alkene 15. Alkylation of 15 with 16 predominantly gave the diene 18. Hydrolysis of the dithiane to the ketone followed by reduction gave mainly the desired equatorial alcohol, which was cleaved oxidatively to (–)-GB17 3. Although there have been many isolated reports of the utility of intramolecular Michael addition as a synthetic method, there has been little systematic investigation. The optimization studies that are the heart of this work are a welcome addition.
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Wilshire, Howard G., Richard W. Hazlett et Jane E. Nielson. « Introduction : Obeying Nature ». Dans The American West at Risk. Oxford University Press, 2008. http://dx.doi.org/10.1093/oso/9780195142051.003.0005.
Texte intégralRésumé :
This book focuses on the human-caused environmental woes of America’s 11 contiguous western states, its mostly arid western continental frontier. In the nineteenth century, penny pamphlets and dime novels mythologized the American west, making icons of its prospectors, “cowboys,” northwestern loggers, and wide open spaces. The west was free of encroaching neighbors and government controls, open to fresh starts. As Robert Penn Warren wrote, in All the King’s Men, “West . . . is where you go when the land gives out and the old-field pines encroach . . . when you are told that you are a bubble on the tide of empire . . . when you hear that thar’s gold in them-thar hills. . . . ” But the “West” was more than gold and oil bonanzas—it was also a land of rich soils, bountiful - sheries, immense, dense forests, desert wonders, and sparkling streams. It is no myth that the western states were America’s treasure house. The romantic myths related to “winning” the west tend to obscure both its basic objective of resource exploitation and the huge public expenditures that supported every aspect, bestowing fortunes on a few. Western resources supported U.S. industrial growth and affluent lifestyle, but now they are highly depleted or largely gone, and the region is in danger of losing the ability to sustain an even moderately comfortable future. Much of what we have done to these magni- cent lands opened them to devastating erosion and pollution. Today, whole mountains are being dismantled to produce metals from barely mineralized zones. Entire regions may be devastated in the attempt to extract the last possible drops of petroleum. We soon could cut down the last remnants of ancient western forests, along with the possibility of ever again seeing their like. Large-scale farming has opened vulnerable western soils to erosion by water and wind, perhaps inviting another dust bowl era. Irrigating vast crop acreages has converted many of them to salt farms, perhaps resembling the conditions that spelled doom for the ancient Babylonian Empire.
Actes de conférences sur le sujet "Salt - free condition"
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Kim, Beom Kyu, Byung Gi Park, Hwa Jeong Han, Ji Hye Park et Won Ki Kim. « An Effect of Bismuth Ion on the Reduction of Terbium Ion in Molten LiCl-KCl Eutectic Salt ». Dans 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-82468.
Texte intégralRésumé :
A salt waste generated from the pyroprocess contains residual actinides and needs to be purified for recycling of the salt and waste conditioning. A co-reduction process could be considered for removal of residual actinides from the salt waste, which contains lanthanides and residual actinides. In the study, specifically, an effect of Bi(III) ion on the electrochemical reaction of Tb(III) ion was investigated in the molten LiCl-KCl eutectic with BiCl3 and TbCl3 at 773 K using electrochemical techniques of cyclic voltammetry, square wave voltammetry and open circuit chronopotentiometry. Tb(III) has a single redox couple without Bi(III). However, the cyclic voltammograms obtained at tungsten electrode in LiCl-KCl-BiCl3-TbCl3 showed four redox couples. The square wave voltammogram in same condition also showed five reduction peaks. Cyclic voltammogram and square wave voltammogram was resolved to find the accurate peaks for redox reaction. Each peak indicates the formation of Tb-Bi intermetallic compound except Tb(III) reduction peak. From the phase diagram of Tb-Bi, it is inferred that each peak corresponds to TbBi2, TbBi, Tb4Bi3, and Tb5Bi3. The open circuit chronopotentiometry was conducted to estimate Gibbs free energy of formation of Tb-Bi intermetallic compound. The experimental results obtained from three kind of the electrochemical techniques showed that Tb-Bi intermetallic compounds were electrochemically formed under potential of Tb(III) reduction potential by co-reduction of Bi(III) and Tb(III). These results indicate that underpotential deposition by co-reduction could be used for Tb(III) removal from the salt waste with Bi(III).
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Auburtin, Erwan, Guillaume Toutin et Ahmad Fahmi Bin Mahmud. « An Experimental and Numerical Assessment of Moss-Type LNG Carrier Seakeeping Moored to PETRONAS FLNG in Partially Filled Condition ». Dans ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-77892.
Texte intégralRésumé :
Moss-type LNG carriers (LNGC) — equipped with spherical LNG tanks — have successfully performed multiple side-by-side (SBS) offloading operations from the PETRONAS FLNG (PFLNG1) terminal since first gas in late 2016. Such LNGC are well suited for these operations as by essence their tanks mitigate the liquid impact risk, for any filling ratio. However, regardless of the LNG tanks shape, the accurate assessment of the relative motion between PFLNG1 and a SBS-moored LNGC was critical for designing the mooring and offloading systems — in particular the LNG Marine Loading Arms (MLA) — and subsequently assessing the terminal operability. While the issue has been extensively studied for LNGC equipped with prismatic tanks (SALT I & II JIPs [4]) and a good agreement achieved with numerical models using potential theory, literature available on coupling with LNG sloshing in spherical tanks in a SBS mooring configuration is rare. Compared with prismatic tanks, the axisymmetric tank geometry is not restricting the main sloshing modes direction: these modes are therefore free to rotate due to LNGC wave-induced motions. An experimental wave basin model test campaign has been held at the MARIN facility to assess the behavior of a Moss-type LNGC with partially filled tanks and provide a good quality database for numerical model calibration and relative motion prediction. This carrier, equipped with Plexiglas spherical tanks, has been tested in free-standing conditions and SBS-moored to PFLNG1. A variety of loading conditions was covered for the LNGC including ballast, 20% and 50% filling. Sloshing modes have been captured with dedicated cameras and wave probes implemented in the LNGC tanks. In this paper, the model test set-up is presented and a comparison is made between the experiments and numerical simulations, using the potential theory software Diodore™, accounting for the hydrodynamic interaction between the vessels and the coupling with the liquid motion in tanks. Particular attention is paid to the coupling effects between longitudinal and transverse motions induced by the longitudinal asymmetry, and their consequences on the design of the offloading system.
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Arosio, Franco, et Ingo Lange. « Lifetime Protection of Iron Casted Brake Discs for Electric Vehicles through Advanced Heat Treatment Technology ». Dans EuroBrake 2021. FISITA, 2021. http://dx.doi.org/10.46720/1978791eb2021-mds-006.
Texte intégralRésumé :
The rise of Electrical Vehicles (EVs) is unstoppable and EVs will become a key part of the mainstream automotive market. According to recent post-COVID-19 scenarios based on IHS data, EVs will surge up to 14% of global passenger car sales in 2027 and go up to 57% in 2040. The electrification of future mobility concepts is going along with new requirements also for the brake system. EVs with regenerative braking applications utilize the traditional friction brakes in fewer circumstances due to recuperation: therefore the risk of superficial corrosion increases. In case of an emergency brake situation the basic requirement is that the braking surface will be free of corrosion to have maximum brake power. Thus, the corrosion-free condition on the braking surface is a safety requirement at any time. The state of the art solution consists of paintings or “coatings”, such as ultraviolet (UV)-hardening paint, Zn or Zn/Al paints, which can perform well in new conditions (e.g. up to 120 hours in standard UNI ISO 9227 salt fog chamber). But these solutions will be easily abraded within approximately 20 standard-condition braking applications. The corrosion-free condition during the lifetime of the disc is not achieved yet in the current state of the art; rust or corrosion can seriously downgrade the braking performances. This paper is describing an innovative 2-step process to improve the corrosion and wear resistance of standard cast iron brake discs. In the first step, the amount of undesired graphite lamellae will be reduced from the surface with customized parameters, according to the individual types of grey cast iron material of the substrate. This pre-process is followed by a thermochemical diffusion process including controlled oxidation of the substrate resulting in high corrosion protection of the rotors. The authors will produce proof of corrosion resistance up to 300 hours in salt conditions according to UNI ISO 9277. In addition, bench tests and vehicle endurance tests have been performed in cooperation with Tier 1 and OEMs and have shown increased wear resistance even with non-electric cars and with standard ECE brake pads. The novel surface solution could be also applied to non-functional areas of the brake disc like cooling channels, bell and swan neck in order to substitute the current paintings. In summary, the new 2-step heat treatment process is a price competitive solution for corrosion protection of functional and non-functional areas of iron casted brake discs over the entire lifetime, especially on EVs with strong recuperation. But this solution also works for hybrid and conventional cars in preferably on the rear axis with low-abrasive brake pads (e.g. NAO pads). Finally, even when the vehicle fleet goes all-electric, dust emission from brakes and tyres will still pollute the environment. Addressing this topic, the authors will provide an outlook of the ongoing activities to reduce brake dust emissions with innovative surface solutions.
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Gan, Yu, et Van P. Carey. « An Exploration of the Effects of Dissolved Ionic Solids on Bubble Merging in Water and Its Impact on the Leidenfrost Transition ». Dans 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-23330.
Texte intégralRésumé :
Theoretical models and MD simulation studies suggest that dissolved salts tend to alter the surface tension at liquid vapor interfaces and affect the stability of the free liquid film between adjacent bubbles. Recent modeling of the Leidenfrost phenomenon also indicates that bubble merging is a key mechanism affecting the Leidenfrost transition conditions. This investigation summarizes the results of an investigation of the effects of dissolved salts on liquid film stability and bubble merging in the aqueous solution. The interaction of pairs of bubbles injected into solution with different dissolved salt concentrations was studied experimentally to determine the probability of merging from statistics for ensembles of bubble pairs. The results of these experiments indicate that very low dissolved salt concentrations can strongly reduce the tendency of adjacent bubbles to merge, implying that the presence of the dissolved salt in such cases strongly enhances the stability of the free liquid film between adjacent bubbles. The trends are compared to predictions of free liquid film stability by wave instability theory and MD simulations. These trends are also compared to experimental data indicating the effects of dissolved salt on the Leidenfrost transition. These comparisons indicate that the suppression of merging due to the effects of some dissolved salts can significantly alter the Leidenfrost transition conditions. The implications of this in quenching of cast aluminum or steel parts using water of variable hardness are also discussed.
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Polo, Marco Angel Gabriel, Fabiano Bertoni, Judimar Clevelario, Fabrício Pinheiro dos Santos et Mario Luis Ribeiro. « Flexible Pipes Integrity Assessment in Field Campaign with Novel Mobile Annulus Testing System ». Dans Offshore Technology Conference. OTC, 2022. http://dx.doi.org/10.4043/31808-ms.
Texte intégralRésumé :
Abstract Flexible pipes annulus condition is a key concern regarding the pipe's integrity. The presence of water in the annulus may lead to a corrosive environment which reduces the fatigue life of the tensile armours. Annulus flooding is the most frequent failure case [1] and may occur due to a failure on the external sheath, failure of the end fitting sealings or failure of the vent valves installed in the end fittings. Water may also reach the annulus not from the outside but as condensation of the permeated gases from the bore. One of the current approaches to assess the annulus condition consists in the detection of annulus flooding through free volume measurment by means of a positive pressure test or a vacuum test. This intervention may be complemented by gas sampling from the annulus and measurement of bore-to-annulus gas flow permeation rates. Conventional venting systems on the top end fitting typically do not allow for these operations but for approximations of permeation flow rate by monitoring of annulus pressure build-up because of pressure sensors installed in the venting system. To address flexible pipes integrity, the Mobile Annulus Testing System (MATS) was developed. MATS allows for the determination of free annulus measurement, by means of conventional positive pressure or vacuum testing. Moreover, MATS allows for permeation gas flow rate measurement and gas sampling. Also, MATS is easily deployable and can be transported as cargo on flight helicopters. MATS was tested on a field campaign in 09 flexible risers in the Tupi Field in Santos Basin, brazilian pré-salt, and this paper presents the results obtained.
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Polo, Marco Angel Gabriel, Fabiano Bertoni, Judimar Clevelario, Fabrício Pinheiro dos Santos et Mario Luis Ribeiro. « Flexible Pipes Integrity Assessment in Field Campaign with Novel Mobile Annulus Testing System ». Dans Offshore Technology Conference. OTC, 2022. http://dx.doi.org/10.4043/31808-ms.
Texte intégralRésumé :
Abstract Flexible pipes annulus condition is a key concern regarding the pipe's integrity. The presence of water in the annulus may lead to a corrosive environment which reduces the fatigue life of the tensile armours. Annulus flooding is the most frequent failure case [1] and may occur due to a failure on the external sheath, failure of the end fitting sealings or failure of the vent valves installed in the end fittings. Water may also reach the annulus not from the outside but as condensation of the permeated gases from the bore. One of the current approaches to assess the annulus condition consists in the detection of annulus flooding through free volume measurment by means of a positive pressure test or a vacuum test. This intervention may be complemented by gas sampling from the annulus and measurement of bore-to-annulus gas flow permeation rates. Conventional venting systems on the top end fitting typically do not allow for these operations but for approximations of permeation flow rate by monitoring of annulus pressure build-up because of pressure sensors installed in the venting system. To address flexible pipes integrity, the Mobile Annulus Testing System (MATS) was developed. MATS allows for the determination of free annulus measurement, by means of conventional positive pressure or vacuum testing. Moreover, MATS allows for permeation gas flow rate measurement and gas sampling. Also, MATS is easily deployable and can be transported as cargo on flight helicopters. MATS was tested on a field campaign in 09 flexible risers in the Tupi Field in Santos Basin, brazilian pré-salt, and this paper presents the results obtained.
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Morooka, Celso K., Mauricio J. H. Suzuki et Paulo S. D. Pereira. « A Comparative Analysis of Ultra Deep Water Catenary Rigid Risers ». Dans ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/omae2010-20415.
Texte intégralRésumé :
The ever increase of global demand for petroleum and natural gas brings needs to discover new petroleum fields. Particularly in the Brazilian coast, these discoveries are located on more and more remote areas combined with harsh and aggressive petroleum fluid production, such as the case of recently announced pre-salt petroleum fields. Development of offshore systems for field production in this scenario demands sophisticated and innovative technological solutions. It brings the necessity for developments of frontier technologies to make viable design of oil and gas production systems to be applied for ultra deep water depth applications. Production riser is a very critical component of most offshore petroleum production systems. Riser acts as a physical connection between subsea wells and floating production facility at the sea surface. It conducts the oil and gas production, and sometimes, fluid or gas for injection into the petroleum reservoir. Wellhead control commands are also guided between the floating platform and the subsea system throughout the riser system. In the literature, many different riser systems have been proposed and extensively discussed for ultra deep water applications. Among others configurations, Steel Catenary Riser (SCR) appears as a technically feasible and economically viable solution. This system is comprised with a free hanging steel pipe, suspended from the platform directed to the wellhead in a catenary shape. In ultra deep water, the riser weight itself commonly is the limitation for application of this type of riser system. Once it requires a much more expensive floating production platform with larger capacity. Furthermore, it also can cause high concentrated stresses in some regions along the riser structure. Catenary shaped risers with lighter material such as Aluminum seem to be a very attractive alternative due to the great riser weight reduction observed. The present paper describes and proposes procedures for the design and operation of petroleum production riser system for ultra deep water application to produce high flow rate of oil and gas in a typical pre-salt petroleum field offshore Brazil condition. Results and discussions are shown through comparisons for catenary riser systems composed by steel pipe and other kind of lighter material. Case studies are conducted for water depth up to 3000 meters by parametric analysis. Current and waves effects along with floating platform motions and riser geometries are analyzed in order to identify critical conditions and to depict feasible solutions.
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Josephs, R. E., J. Porlles, O. S. Tomomewo, E. Gyimah et F. Ebere. « Geo-Mechanical Characterization of a Well to Store Hydrogen ». Dans 57th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2023. http://dx.doi.org/10.56952/arma-2023-0528.
Texte intégralRésumé :
ABSTRACT Hydrogen storage holds the potential to address the intermittency of renewables in the power sector as well as provide low-cost emissions-free energy. However, hydrogen (H2) as an energy carrier has a low density and low energy per unit volume at standard conditions. This significantly complicates large-scale storage using chemical and physical methods. Aquifers, salt caverns, and depleted/abandoned oil and gas fields are some of the subsurface options that can be used to store hydrogen underground because they possess the requisite volumes to store H2 at higher pressures. In this study, the recent interest in exploiting salt deposits in North Dakota as hydrogen storage sites is addressed. The Pine salt in the Spearfish Formation and the "A" salt in the Opeche Formation are the thickest and most prevalent of these salts, making them the most viable candidates for these types of ventures. We tested the feasibility of storing hydrogen by analyzing the behavior of the salts through geo-mechanical characterization. We estimated the mechanical properties of the rock salt from log data and considered the stresses of the salt formation to aid understanding and determine possible limitations. Geomechanical characterization showed a typical behavior of stresses, Sv>SH> Sh. INTRODUCTION The intermittency of renewable energy resources has created an urgent need for energy storage. Deployment of energy storage options will accelerate flexibility in grid operations and provide energy that can be applied to a diverse portfolio of industries. It can also provide environmental benefits by improving the overall efficiency of the power grid and providing a basis for the broader adoption of renewable energy thus reducing harmful emissions to the atmosphere (Uliasz-Misiak et al., 2022). According to Tarkowski & Uliasz-Misiak (2022), H2 is a reliable energy carrier that can play an important role in decarbonizing our current energy system. Hydrogen storage can be used to supplement energy demands associated with seasonal heating needs and peak load (Laban, 2020). The challenge with hydrogen however is that it has a higher energy per unit mass than any other liquid fuel. As an energy carrier, H2 has a low density of 0.089 kg/m3 at standard conditions. As such, it is difficult to store large volumes using chemical and physical storage methods (Lord, 2014). Currently, H2 storage can be stored on a small scale as compressed gas at around 5076 – 13778 psi in type 2, 3 or 4 tanks. In order to store gas at such high pressures, the capital and operational expenditures are significant. On medium scale, it can be potentially stored as a gas in spherical vessels at low pressures of ∼290psi thus requiring larger volume (Papadias & Ahluwalia, 2021).
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Cho, Yung-Zun, In-Tae Kim, Hee-Chul Yang, Hwan-Seo Park et Han-Soo Lee. « Separation of Lanthanide Fission Products in a Eutectic Waste Salts Delivered From Pyroprocessing of a Spent Oxide Fuel by Using Lab-Scale Oxidative Precipitation Apparatus ». Dans ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2009. http://dx.doi.org/10.1115/icem2009-16127.
Texte intégralRésumé :
Co-precipitation experiments of lanthanides were carried out using this lab-scale apparatus (4kg-salt/batch). As lanthanides, 8 lanthanide elements (Y, La, Ce, Pr, Nd, Sm, Eu and Gd) were used. By reaction with oxygen, these 8 lanthanide chlorides were converted their oxide (REO2, RE2O3) or oxychloride form. Since these lanthanide oxides or oxychlorides are nearly molten salt insoluble, they all were precipitated by free settling in the bottom of molten salt bed, where about 7–8 hrs precipitation time was requested. It was found that in the conditions of 700 °C - 12 hours sparging time and 5 L/min, all the used lanthanide elements showed over 99.5% oxidation efficiency. But in case of 800 °C molten salt temperature only after 7 hours they showed over 99% oxidation efficiency.
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Ferreira, Vitor Hugo de Sousa, Manuel Castro, Renato Moura, Rafael de Oliveira Werneck, Marcelo Ferreira Zampieri, Maiara Moreira Gonçalves, Oscar Linares et al. « A New Hybrid Data-Driven and Model-Based Methodology for Improved Short-Term Production Forecasting ». Dans Offshore Technology Conference. OTC, 2023. http://dx.doi.org/10.4043/32167-ms.
Texte intégralRésumé :
Abstract Model-based (MB) solutions are widely used in reservoir management and production forecasting throughout the life-cycle of oil fields. However, such approaches are not often used for short-term (up to six months) forecasting due to the immediate-term productivity missmatch and the large number of models required to honor uncertainties. Recently developed data-driven (DD) techniques have shown promising performance in immediate term forecasting (from days to months) while losing performance as the timeframe increases. This work, proposes and investigates a hybrid methodology (HM) that combines MB and DD techniques focusing on improving the short-term production forecast. A common practice in reservoir management to understand the impact of uncertainties, is to build an ensemble of simulation model scenarios to assess the impact of these uncertainties on production forecasts. The proposed HM relies on the DD-assisted selection of a subset of models from the set of assimilated (posterior) models. Specifically, the pool of MB models is ranked based on their similarities to the DD production forecasts in the immediate term (e.g., one month), followed by the selection of the top models. The selected MB models are then used in the short-term forecasting task. In a case study for an offshore pre-salt reservoir benchmark, the proposed HM is compared to two baselines: one purely DD and another fully MB. The case study considered two forecasting conditions: human intervention-free with restrictions (HIF-R), with no intervention in the controls except to follow physical restrictions, and with human interventions (WHI), following optimization rules. Our results showed that the HM significantly outperformed the MB baseline, regardless of forecasting condition (HIF-R and WHI) or variables (pressure and oil/water/gas rates) for all evaluation metrics (time series similarity and rank-based) and top-selected models tested. The hybrid approach also helped improve the well productivity uncertainty that emerged from the data assimilation. Such results indicate that the performance of MB short-term forecasts can be enhanced when assisted by DD techniques, such as in our proposed HM. Comparing these two approaches, the best forecasts were split between the HM and the DD baseline. In the partially idealized HIF-R conditions, the DD baseline was best when the forecast trend was steady. However, the HM was superior for the more complex production behaviors. In the more realistic WHI conditions, the HM outperformed the DD baseline in almost every aspect tested given the inability of the chosen DD technique to leverage known interventions. This work is the first effort to improve MB short-term production forecasts, using production data, with a machine learning technique through a proposed HM. The proposed DD-assisted selection of models proved successful in a benchmark case study, which means it is promising for application in other fields and for further development.
Rapports d'organisations sur le sujet "Salt - free condition"
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Ningthoujam, J., J. K. Clark, T. R. Carter et H. A. J. Russell. Investigating borehole-density, sonic, and neutron logs for mapping regional porosity variation in the Silurian Lockport Group and Salina Group A-1 Carbonate Unit, Ontario. Natural Resources Canada/CMSS/Information Management, 2024. http://dx.doi.org/10.4095/332336.
Texte intégralRésumé :
The Oil, Gas and Salt Resources Library (OGSRL) is a repository for data from wells licenced under the Oil, Gas and Salt Resources Act for Ontario. It has approximately 50,000 porosity and permeability drill core analyses on bedrock cores. It also has in analogue format, geophysical logs (e.g., gamma ray, gamma-gamma density, neutron, sonic) from approximately 20,000 wells. A significant challenge for geotechnical and hydrogeological studies of the region is the accessibility of digital data on porosity and permeability. Recent work completed on approximately 12,000 core analyses for the Silurian Lockport Group and Salina Group A-1 Carbonate Unit are geographically concentrated within productive oil and gas pools. An opportunity therefore exists to expand the bedrock porosity characterization for southern Ontario by using geophysical logs collected in open-hole bedrock wells that are more geographically dispersed. As part of this study, hard copy files of analog geophysical logs are converted to digital data (LAS format), followed by quality assessment and quality control (QAQC) to obtain meaningful results. From the digitized geophysical data, density, neutron, and sonic logs are selected to mathematically derive porosity values that are then compared with the corresponding measured core porosity values for the same depth interval to determine the reliability of the respective log types. In this study, a strong positive correlation (R²=0.589) is observed between porosity computed from a density log (density log porosity) and the corresponding core porosity. Conversely, sonic log porosity and neutron porosity show weak (R2 = 0.1738) and very weak (R2 = 0.0574) positive correlation with the corresponding core porosity data. This finding can be attributed to different factors (e.g., the condition of the borehole walls and fluids, the type and limitations of the technology at different points in time, knowledge of formation variability for calculations), and as such requires more investigation. The density log measures the bulk density of the formation (solid and fluid phases), and as such the derived porosity values indicate total porosity i.e., interparticle (primary) pore spaces, and vugs and fractures (secondary) pore spaces. The sonic log measures the interval transit time of a compressional soundwave travelling through the formation. High quality first arrival waveforms usually correspond to a route in the borehole wall free of fractures and vugs, which ultimately result in the derived porosity reflecting only primary porosity. As molds, vugs and fractures contribute significantly to the total porosity of the Lockport Group and Salina A-1 Carbonate strata, sonic porosity may not reflect true bulk formation porosity. The neutron porosity log measures the hydrogen index in a formation as a proxy for porosity, however, the current limitations of neutron logging tool fail to account for formation-related complexities including: the gas effect, the chloride effect and the shale effect that can lead to over- or underestimation of formation porosity. As a result, the density log appears to be the most reliable geophysical log in the OGSRL archives for total porosity estimation in the Lockport Group and Salina A-1 Carbonate Unit. Nonetheless, sonic porosity can be combined with density porosity to determine secondary porosity, whereas a combination of density and neutron porosity logs can be used to identify gas-bearing zones.