Bibliographies thématiques / Chemical reverse approach

Littérature scientifique sur le sujet « Chemical reverse approach »

Auteur : Grafiati

Publié le 10 mars 2023

Mis à jour le 11 mars 2023

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Articles de revues sur le sujet "Chemical reverse approach"

Perrot, Thomas, Guillaume Salzet, Nadine Amusant, Jacques Beauchene, Philippe Gérardin, Stéphane Dumarçay, Rodnay Sormani, Mélanie Morel‐Rouhier et Eric Gelhaye. « A reverse chemical ecology approach to explore wood natural durability ». Microbial Biotechnology 13, n^o 5 (25 mars 2020) : 1673–77. http://dx.doi.org/10.1111/1751-7915.13540.

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Becattini, Barbara, et Maurizio Pellecchia. « SAR by ILOEs : An NMR-Based Approach to Reverse Chemical Genetics ». Chemistry - A European Journal 12, n^o 10 (20 mars 2006) : 2658–62. http://dx.doi.org/10.1002/chem.200500636.

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Wang, Zhen, Faryal Chaudhry, Maria Naseem et Adnan Asghar. « Reverse Zagreb and Reverse Hyper-Zagreb Indices for Crystallographic Structure of Molecules ». Journal of Chemistry 2020 (13 mars 2020) : 1–12. http://dx.doi.org/10.1155/2020/9805829.

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In the fields of chemical graph theory, topological index is a type of a molecular descriptor that is calculated based on the graph of a chemical compound. Topological indices help us collect information about algebraic graphs and give us mathematical approach to understand the properties of algebraic structures. With the help of topological indices, we can guess the properties of chemical compounds without performing experiments in wet lab. There are more than 148 topological indices in the literature, but none of them completely give all properties of under study compounds. Together, they do it to some extent; hence, there is always room to introduce new indices. In this paper, we present first and second reserve Zagreb indices and first reverse hyper-Zagreb indices, reverse GA index, and reverse atomic bond connectivity index for the crystallographic structure of molecules. We also present first and second reverse Zagreb polynomials and first and second reverse hyper-Zagreb polynomials for the crystallographic structure of molecules.

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Sanmartino, J. A., M. Khayet, M. C. García-Payo, H. El-Bakouri et A. Riaza. « Treatment of reverse osmosis brine by direct contact membrane distillation : Chemical pretreatment approach ». Desalination 420 (octobre 2017) : 79–90. http://dx.doi.org/10.1016/j.desal.2017.06.030.

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Yang, C. Y., F. S. Lee, L. Chan, D. A. Sparrow, J. T. Sparrow et A. M. Gotto. « Determination of the molecular mass of apolipoprotein B-100 A chemical approach ». Biochemical Journal 239, n^o 3 (1 novembre 1986) : 777–80. http://dx.doi.org/10.1042/bj2390777.

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Apolipoprotein B-100 (apo B-100) is the protein ligand in low-density lipoproteins that binds to a specific cell-surface receptor. Its molecular mass has been a subject of controversy. We have determined the molecular mass of the protein by a chemical approach. After complete CNBr cleavage, the C-terminal fragment of apo B-100 was purified by reverse-phase h.p.l.c. Amino acid N- and C-terminal analyses confirm that this peptide represents the C-terminal peptide as deduced from the DNA sequence of a human apo B-100 cDNA clone. A chemically synthesized peptide was used to determine the recovery of the peptide (74.72%). On the basis of these data, the molecular mass of apo B-100 was determined to be 496.82 +/- 24.84 kDa.

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Dorhjie, Desmond Batsa, Roman Yusupov, Vladislav Krutko et Alexey Cheremisin. « Deviation from Darcy Law in Porous Media Due to Reverse Osmosis : Pore-Scale Approach ». Energies 15, n^o 18 (12 septembre 2022) : 6656. http://dx.doi.org/10.3390/en15186656.

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Shale and tight hydrocarbons are vital to global energy dynamics. The fluid flow in sub-micron pores of tight oil reservoirs varies from bulk fluid flow. The Darcy law is widely accepted to model creeping flow in petroleum reservoirs. However, traditional reservoir modeling approaches fail to account for the sub-micron mechanisms that govern fluid flow. The accuracy of tight oil reservoir simulators has been improved by incorporating the influence of sub-micron effects. However, there are still factors that affect sub-micron fluid mobility that need investigation. The influence of a chemical potential gradient on fluid flow in sub-micron pores was modeled by solving Darcy and the transport and diluted species equations. The findings indicate that when a chemical potential gradient acts in the opposite direction of a hydraulic pressure gradient (reverse osmosis), there exists a limiting pressure threshold below which a non-linear flow pattern deviating from the Darcy equation is observed. Furthermore, the simulation based on tight reservoir pore parameters shows that when the effect of a chemical potential gradient is added, the resultant flux is 8–49% less. Hence, including the effect of the chemical potential gradient will improve the accuracy of sub-micron pressure dynamics and flow velocity.

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Chen, Yushu, Magali Duvail, Philippe Guilbaud et Jean-François Dufrêche. « Stability of reverse micelles in rare-earth separation : a chemical model based on a molecular approach ». Physical Chemistry Chemical Physics 19, n^o 10 (2017) : 7094–100. http://dx.doi.org/10.1039/c6cp07843e.

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Xu, Chong, Fuxiang Yang, Shuanggang Duan, Dongzhen Li, Lei Li, Manqun Wang et Aiming Zhou. « Discovery of behaviorally active semiochemicals in Aenasius bambawalei using a reverse chemical ecology approach ». Pest Management Science 77, n^o 6 (13 mars 2021) : 2843–53. http://dx.doi.org/10.1002/ps.6319.

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G. Ponomareva, Alla, Yevgen P. Yurenko, Roman O. Zhurakivsky, Tanja van Mourik et Dmytro M. Hovorun. « Conformational Landscape of the Nucleoside Reverse Transcriptase Inhibitor d4T : a Comprehensive Quantum-Chemical Approach ». Current Physical Chemistry 3, n^o 1 (1 janvier 2013) : 83–92. http://dx.doi.org/10.2174/1877946811303010012.

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Choo, Young-Moo, Pingxi Xu, Justin K. Hwang, Fangfang Zeng, Kaiming Tan, Ganga Bhagavathy, Kamlesh R. Chauhan et Walter S. Leal. « Reverse chemical ecology approach for the identification of an oviposition attractant for Culex quinquefasciatus ». Proceedings of the National Academy of Sciences 115, n^o 4 (8 janvier 2018) : 714–19. http://dx.doi.org/10.1073/pnas.1718284115.

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Pheromones and other semiochemicals play a crucial role in today’s integrated pest and vector management strategies. These semiochemicals are typically discovered by bioassay-guided approaches. Here, we applied a reverse chemical ecology approach; that is, we used olfactory proteins to lead us to putative semiochemicals. Specifically, we used 7 of the top 10 odorant receptors (ORs) most expressed in the antennae of the southern house mosquito, Culex quinquefasciatus, and which are yet to be deorphanized. We expressed these receptors in the Xenopus oocyte recording system and challenged them with a panel of 230 odorants, including physiologically and behaviorally active compounds. Six of the ORs were silent either because they are not functional or a key odorant was missing. CquiOR36, which showed the highest transcript levels of all OR genes in female antennae, was also silent to all odorants in the tested panel, but yielded robust responses when it was accidentally challenged with an old sample of nonanal in ethanol. After confirming that fresh samples were inactive and through a careful investigation of all possible “contaminants” in the old nonanal samples, we identified the active ligand as acetaldehyde. That acetaldehyde is activating CquiOR36 was further confirmed by electroantennogram recordings from antennae of fruit flies engineered to carry CquiOR36. Antennae of female mosquitoes also responded to acetaldehyde. Cage oviposition and dual-choice assays demonstrated that acetaldehyde is an oviposition attractant in a wide range of concentrations and thus of potential practical applications.

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Thèses sur le sujet "Chemical reverse approach"

Yang, Hui. « Theoretical Studies of Molecular Recognition in Protein-Ligand and Protein-Protein Complexes ». University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1282339026.

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PACINI, GIULIA. « Antigens of diagnostic relevance in autoimmunity : characterization, production strategies and immunoassays development ». Doctoral thesis, 2015. http://hdl.handle.net/2158/1002534.

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Autoimmune disorders (AID) represent a group of chronic and heterogeneous diseases, whose common trait is the immune system reaction against self-components of the organism. Most of the AID have unknown etiology, but it was demonstrated that both genetic and environmental factors are involved in triggering the pathologic mechanism. Because of their chronicity and their debilitating complications, AID have high medical and socioeconomic costs, leading to the crucial necessity to perform an early diagnosis and to monitor the disease follow up. Unfortunately, the available diagnostic and prognostic instruments are often complicated and invasive. In order to develop diagnostic and/or prognostic tools marked by low-invasivity, low-cost, and easy execution, it is crucial to detect trustworthy biomarkers (BM). The BM characterization has a significant importance also because it represents a powerful instrument to disclose the molecular mechanisms involved in the ethiopathogenesis of the disorder of interest. In this context, the main goal of this work is to identify the target(s) of the humoral autoimmune response using the chemical reverse approach, which involves the screening of focused Ag libraries with pts serum. Indeed, in the case of autoimmunity, an easily detectable and reliable BM may be represented by the titer of a specific auto-Ab. A key feature of this study is the evaluation of the role of aberrant post-translational modifications (PTM) in autoimmunity, as it was hypothesized that environmental agents may induce the occurrence of non-natural PTM on self-proteins, uncovering neo-epitopes and triggering the autoimmune response. In particular, the attention was focused on two main topics, which will be treated separately within this presentation: the role of Myelin Oligodendrocyte Glycoprotein (MOG) as putative auto-Ag in central nervous system AID (Chapter 2); investigation of the involvement of aberrant PTM in the ethiopathogenesis of Primary Biliary Cirrhosis (Chapter 3).

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Livres sur le sujet "Chemical reverse approach"

Myers, Sara P., et Matthew D. Neal. Management of Exsanguinating Hemorrhage : Hemostasis and Resuscitation (DRAFT). Sous la direction de Raghavan Murugan et Joseph M. Darby. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190612474.003.0022.

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This chapter describes the approach to massive bleeding in a patient within the setting of rapid response team (RRT) calls. Emphasis is placed on identifying peripheral sources of bleeding that can be controlled with compression. Military experience has aided in the understanding of how zeolite and clay can be used as chemical adjuncts. Resuscitative strategies and transfusion practices that promote hemodynamic stability are reviewed. Concurrent coagulopathy that can exacerbate hemorrhage is addressed and a brief overview is provided demonstrating how commonly prescribed anticoagulants can be monitored and reversed. To illustrate that multimodal therapy is often necessary to control hemorrhage, the chapter closes with surgical and minimally invasive techniques for definitive hemostasis.

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Chapitres de livres sur le sujet "Chemical reverse approach"

Apps, Peter, Lesego Mmualefe et J. Weldon McNutt. « A Reverse-Engineering Approach to Identifying Which Compounds to Bioassay for Signalling Activity in the Scent Marks of African Wild Dogs (Lycaon pictus) ». Dans Chemical Signals in Vertebrates 12, 417–32. New York, NY : Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4614-5927-9_33.

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Nguyen, T. D., Takeshi Matsuura et S. Sourirajan. « A Fundamental Approach to Reverse-Osmosis Concentration and Fractionation of Organic Chemicals in Aqueous Solutions for Environmental Analysis ». Dans Advances in Chemistry, 139–62. Washington, DC : American Chemical Society, 1986. http://dx.doi.org/10.1021/ba-1987-0214.ch007.

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Benmergui, Joshua, Sangeeta Sharma, Deyong Wen et John C. Lin. « Quantitative Attribution of Processes Affecting Atmospheric Chemical Concentrations by Combining a Time-Reversed Lagrangian Particle Dispersion Model and a Regression Approach ». Dans Lagrangian Modeling of the Atmosphere, 251–64. Washington, D. C. : American Geophysical Union, 2013. http://dx.doi.org/10.1029/2012gm001254.

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Zhang, Haoqian, Ao Liu, Yuheng Lu, Ying Sheng, Qianzhu Wu, Zhenzhen Yin, Yiwei Chen, Zairan Liu, Heng Pan et Qi Ouyang. « NETWORK REVERSE ENGINEERING APPROACH IN SYNTHETIC BIOLOGY ». Dans Engineering of Chemical Complexity, 375–91. WORLD SCIENTIFIC, 2012. http://dx.doi.org/10.1142/9789814390460_0019.

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Soni, Vipasha, Jens Abildskov, Gunnar Jonsson et Rafiqul Gani. « A hierarchal approach based on reverse design algorithm for simultaneous design and analysis of product and processes. » Dans Computer Aided Chemical Engineering, 461–66. Elsevier, 2007. http://dx.doi.org/10.1016/s1570-7946(07)80100-3.

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Sassi, Kamal M., et Iqbal M. Mujtaba. « Optimization of Design and Operation of Reverse Osmosis Based Desalination Process Using MINLP Approach Incorporating Fouling Effect ». Dans Computer Aided Chemical Engineering, 206–10. Elsevier, 2011. http://dx.doi.org/10.1016/b978-0-444-53711-9.50042-0.

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Yurekli, Yilmaz. « Principles of Membrane Surface Modification for Water Applications ». Dans Wastewater Treatment [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96366.

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Membrane technologies offer efficient and reliable solutions to separate components from aqueous media. Among them, pressure driven membrane separation processes namely microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) have been preferred in many industrial operations (food, pharmaceutical, chemical, drinking water, wastewater) due to the intrinsic advantages such as high selectivity, stability, ecocompatibility, scalability, flexibility, small footprint and low operational cost. This chapter will focus on the latest developments of surface modified polymeric membranes via the Layer-by-layer self-assembly approach and incorporation/decoration of nanomaterials. Variable parameters including size and charge of polyelectrolyte, ionic strength of the media, number of bilayers, and different types of nanomaterials on the bulk and surface property, water permeability, selectivity, antifouling, antibacterial, and adsorptive properties of the resultant composite membranes will be reviewed by comparison with the neat membranes. Membrane stability in terms of throughput and rejection characteristics during long-term filtrations will be addressed in this chapter.

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Debnath, Sisir. « Micelles and Reverse Micelles : a Fascinating Micro-reactor ». Dans Modern Approaches in Chemical and Biological Sciences, 17–23. Lincoln University College, Malaysia, 2022. http://dx.doi.org/10.31674/book.2022macbs.003.

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Reactions in micro-heterogeneous systems have been found to be of great interest in the past few decades. Two such micro-heterogeneous aggregates are micelles and reverse micelles, which are formed by surface active agents or surfactants. In numerous chemical reactions, the use of these systems as microreactors increases the rate of the reaction up to 10-100 folds. This chapter will be concentrated on micelles and reverse micelles as catalytic reactors since, in the past few decades, numerous numbers of reactions have been successfully carried out in these systems.

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Criss, Robert E. « Nonequilibrium Fractionation and Isotopic Transport ». Dans Principles of Stable Isotope Distribution. Oxford University Press, 1999. http://dx.doi.org/10.1093/oso/9780195117752.003.0006.

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At the Earth’s surface, isotopic disequilibrium is far more common than isotopic equilibrium. Although isotopic equilibrium is approached in certain instances, numerous constituents of the lithosphere, hydrosphere, atmosphere, and biosphere are simply not in mutual isotopic equilibrium. This condition is consistent with the complex and dynamic conditions typical of the Earth’s surface, particularly the large material fluxes, the rapid changes in temperature, and the biological mediation of chemical systems. Fortunately, several aspects of isotopic disequilibrium may be understood in terms of elementary physical laws. For homogeneous phases such as gases or well-stirred liquids, or for cases where spatial gradients in isotopic contents are not of primary interest, then the principles of elementary kinetics can be applied. For cases where isotopic gradients are important, the laws of diffusion are applicable. If two phases are out of isotopic equilibrium, they will progressively tend to approach the equilibrium state with the passage of time. This phenomenon occurs by the process of isotopic exchange, and its rate may be understood by examining isotopic exchange reactions from the viewpoint of elementary kinetic theory. In particular, consider the generalized exchange reaction where A and B are two phases that share a common major element, and A* and B* represent the same phases in which the trace isotope of that element is present. The present analysis is simplified if the exchange reaction is written so that only one atom is exchanged, in which case the stoichiometric coefficients are all unity. For reaction 4.1, kinetic principles assert that the forward and reverse reactions do not, in general, proceed at identical rates, but rather at the rates indicated by the quantities kα and k written by the arrows, multiplied by the appropriate concentrations terms. Assuming that the reaction is first order, then the reaction progress, represented by the quantity dA*/dt, may be expressed by the difference between these forward and reverse rates, as follows: . . . dA*/dt = kα(A)(B*) − k(A*)(B) (4.2) . . . In order to evaluate the exchange process more completely, is important to carefully chose a consistent set of concentrations for substitution equation 4.2.

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Renna, Paolo. « A Review of Research of Coordination Approaches in Distributed Production Systems ». Dans Advances in Civil and Industrial Engineering, 93–112. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-2098-8.ch006.

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The increasing of global competition and the need for rapid response to market changes drive manufacturing enterprises to adopt new business models. This chapter examines the recent years of research developed in the field of coordination approaches to support distributed production systems. The papers discussed concern the period of 2004-2010 published in international ISI journals. The research articles are classified according to nine fields of research: operational research models; collaborative architecture; negotiation and bargaining models; capacity exchange; revenue sharing; chemical engineering; electronic approach; general review; case study. The analysis of the literature highlights that the articles are distributed uniformly over the years analyzed. The most fields investigated are the collaborative architecture and operational research models, while emerging fields are the chemical engineering and revenue sharing based approaches. The discussion underlines the limitation of the literature and suggests the directions for future research.

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Actes de conférences sur le sujet "Chemical reverse approach"

Franco, Thiago A. « Reverse chemical ecology-based approach for the identification of repellents for a Chagas disease vector,Rhodnius prolixus ». Dans 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.113842.

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Goldthwaite, Donald, Mohamad Metghalchi et James C. Keck. « Refinement of Reduced Chemical Mechanisms for the Modeling of the Rapid Compression Combustion of Heptane and Octane ». Dans ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81368.

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Reduced chemical mechanisms for heptane and octane, originally developed by Keck and Hu, have been shown to give excellent agreement with experimental ignition delay times obtained using a rapid compression machine. These mechanisms consist of 20 species and 41 reactions with 10 reactions detailing the initial breakdown sequence of the alkane, 2 global reactions leading to the formation of end products, and the remaining reactions specifying the path to equilibrium products. Until recently, the success of these mechanisms in matching experimental data rested in large part on the fine tuning of forward rates, and the inclusion of specified reverse rates. For a given reaction, the calculation of the reverse rate from the forward rate and the equilibrium constant—detailed balancing—is the technically correct approach, and the focus of this work was the elimination of the specified reverse rates in favor of this approach. Elimination of the specified reverse rates was found to depend on the accuracy of the thermodynamic property data generated with NASA style polynomial coefficients. Both mechanisms are now able to match experimental data generated with the M.I.T. rapid compression machine with impressive agreement, by employing detailed balancing for the calculation of reverse rates. Current computation techniques include the Detailed and Rate Controlled Constrained Equilibrium methods. However, at the present time, only the detailed method includes the algorithm to model the rapid compression sequence. Work to incorporate the algorithm into the RCCE computation is now underway.

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Rubin, Rachamim, Jacob Karni et Jacob Yeheskel. « Chemical Kinetics Simulation of High Temperature Hydrocarbons Reforming in a Solar Reactor ». Dans ASME 2003 International Solar Energy Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/isec2003-44032.

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This study is aimed at developing a simulation model of a solar Volumetric reactor for hydrocarbon reforming, operating at high temperature and pressure. It will then be used to optimize the reactor design and analyze its performance. The model development utilizes previous and on-going experimental work on Volumetric receiver and catalyst development. The reaction’s kinetics are computed, using the CHEMKIN II simulation package. The chemical kinetic modeling of the relevant C-H-O system is based on: (i) Definition of the relevant computation domain and parameters: temperature, pressure, reactant compositions, residence time, and catalyst load, (ii) Utilizing laboratory measurements at 700–1400K and 1–4 bar. to quantify the kinetic parameters for both, H2O, and CO2 reforming of CH4 and for the Reverse Water Shift reaction. Calculated and measured data are compared for three representative cases, showing a good agreement. The results indicate that the Arrhenius method can be a viable and practical way to predict the behavior of steam and CO2 reforming over a range of temperatures and pressures. Furthermore, it is shown that the present approach can provide a method for estimating the desirable dimensions of the reactor for reforming of CH4. Additional, on-going computational and experimental work, which would provide a more accurate simulation, can easily be implemented using the present numerical model.

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Ray, Valery, Josef V. Oboňa, Sharang Sharang, Lolita Rotkina, Eddie Chang et Kevin Tolua. « Optimizing Gas-Assisted Processes for Ga and Xe FIB Circuit Edit Application ». Dans ISTFA 2016. ASM International, 2016. http://dx.doi.org/10.31399/asm.cp.istfa2016p0397.

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Abstract Despite commercial availability of a number of gas-enhanced chemical etches for faster removal of the material, there is still lack of understanding about how to take into account ion implantation and the structural damage by the primary ion beam during focused ion beam gas-assisted etching (FIB GAE). This paper describes the attempt to apply simplified beam reconstruction technique to characterize FIB GAE within single beam width and to evaluate the parameters critical for editing features with the dimensions close to the effective ion beam diameter. The approach is based on reverse-simulation methodology of ion beam current profile reconstruction. Enhancement of silicon dioxide etching with xenon difluoride precursor in xenon FIB with inductively coupled plasma ion source appears to be high and relatively uniform over the cross-section of the xenon beam, making xenon FIB potentially suitable platform for selective removal of materials in circuit edit application.

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Taylor, James W., Thomas L. Brown et David R. Bassett. « Image reversal : a new chemical approach using isoureas ». Dans Microlithography '90, 4-9 Mar, San Jose, sous la direction de Michael P. C. Watts. SPIE, 1990. http://dx.doi.org/10.1117/12.20107.

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Varma, Nakul, Yash Koshatwar, Manish Kumar, Anatoly Savelyev, Aneesh Jha, Rekha Kumari, Ankesh Nagar et al. « Deterministic Approach Towards Well Intervention Candidate Selection & ; Quantification of Parameters in Esp & ; Jet Pump Wells ». Dans SPE Conference at Oman Petroleum & Energy Show. SPE, 2022. http://dx.doi.org/10.2118/200174-ms.

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Abstract This paper aims to describe a model created to determine various important parameters to monitor oil producer wells with different artificial lift types: Jet Pump (JP) and Electric Submersible Pump (ESP) of Mangala & Aishwarya fields. The fields contain medium gravity viscous crude (10-40cp) in high permeability (1-5 Darcy) sands. In order to overcome adverse mobility ratio and improve sweep efficiency, polymer flooding was adopted. As the Polymer flooding proceeded, polymer breakthrough in producer wells was observed. The major challenges faced in producer wells is polymer/scale depositions realized during well interventions. This issue has surfaced in field due to polymer breakthrough in oil producers and mixing of produced polymer concentration in well fluid with scales, wax or other bivalent ions. Major concerns due to polymer deposition included, fouling of artificial lift system, decrease of well uptime, jet pump (type of artificial lift) & ESP efficiency decrease. ESP & Reverse jet pumping are the major artificial lifts for the field, where power fluid is pumped through annulus and production is taken through tubing. With continued jet Pump fouling due to Polymer, wax & scale agglomerate, well uptime decreased. During jet pump redressing, polymer deposition has been observed in the body X-over (reservoir liquid path), check valve assembly, throat and spacer nozzle to throat inside jet-pump. Thus, a necessity was felt to address the issue with a proactive approach. Continuous chemical dosing method was tried and proven successfully, but it was not cost effective. Hence empirical based modelling was required which can quantify these parameters to plan for well intervention & well clean-up jobs. The developed model is "intelligent" and determines various parameters like – Productivity index(PI) of jet pump well without having suction pressure data, jet pump nozzle loss coefficient, ESP pump efficiency (ESP wear), annulus deposition & debris deposition in tubing reducing effective ID of annulus & tubing respectively. The model calculates from every newly logged Multiphase flowmeter rates, water cut, Annulus pumping pressure & tubing head pressure (THP) events and determines its approach of marking the risk levels of a well. With continued JP/ESP fouling, tubing deposition & PI drop due to Polymer, wax & scale agglomerate, well uptime & production rate is decreased.

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Kumar, Manish, Nakul Varma, Saurabh Badhe, Sachin Pawar, Shailesh Chauhan, Avinash Bohra et Anatoly Savelyev. « Artificial Lift Optimization with Data Based Predictive Approach for Pre-Emptive Changeovers of Jet Pump in Polymer Flooded Field ». Dans International Petroleum Technology Conference. IPTC, 2023. http://dx.doi.org/10.2523/iptc-22720-ms.

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Abstract Mangala field is one of the largest discovered group of oil fields in Barmer Basin, Rajasthan, India. The fields contain medium gravity viscous crude (10-40cp) in high permeability (1-5 Darcy) sands. Currently the field is on polymer flood to improve the sweep efficiency during enhanced oil recovery. As expected, polymer breakthrough was observed in producer wells. However, this has resulted in challenging well interventions due to polymer/scale depositions in the wellbore and Downhole artificial lift equipment. This issue has surfaced due to mixing of produced polymer with scales, wax and various bivalent ions. Major concerns due to polymer deposition included, fouling of artificial lift system, decrease of well uptime and decreased efficiency of jet pump (type of artificial lift). Reverse jet pumping, where power fluid is pumped through annulus and production is taken through tubing, is the most common method of artificial lift for the field. During jet-pump redressing, polymer deposition has been observed in the Body X-over (Reservoir liquid path), check valve assembly, throat and spacer nozzle to throat inside jet-pump. Continuous chemical injection was tried and proved to be a technical success, but it was not cost effective. Hence data-based predictive approach for pre-emptive changeovers of Jet Pump was developed. The developed model is "intelligent". It learns from every newly logged event and auto correct its approach of marking the risk levels of a well. The well intervention history of over 1000+ well interventions in 170+ oil producers were recorded. The recorded data was then studied for sensitivities such asnumber of interventions viz. – wire scratcher run and Jet pump retrieval / installation runsObservations on severity of polymer/scaling issueChemical soaking requirement of chelating agents such as EDTA, DTPA for dispersing polymer,Well downtimeHistories of slickline fishing events, stuck BHAs. The data was then analyzed and used to create a well intervention risk matrix which in turn classifies all 170 wells into low, moderate and high-risk wells. This approach also sets a predictive timeline for individual well failures. The model/approach is intelligent enough to learn from operational history and auto-corrects itself every time a new event is logged. This paper addressesFormation of agglomerated polymer lumps due to scale formation inside well completions.Deposition of polymer layer inside completion equipment and production tubingDetailed stepwise analysis of over 1000+ well intervention in oil producers producing oil and polymer mixed water.Basis of logic for creating a predictive sheet for Jet Pump change outs.Predict optimal Intervention frequency for every well to de-risk jet pump change slickline interventionDetermination of critical wells which have severe deposition issuesTracking of rigless units’ efficiency and planning, especially highly mobile slickline unitOptimize production from fieldPlan for chemical soaking in tubing of wells where polymer and scale deposition are predicted. This paper gives a new approach to those E&P companies who are producing their field on Jet pumps and are using Polymer flood as recovery mechanism. The use of this approach from day zero in such fields would help to create a customized analytical approach for the field and hence reduce production downtime.

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Doty, F. David, Laura Holte et Siddarth Shevgoor. « Securing Our Transportation Future by Using Off-Peak Wind Energy to Recycle CO2 Into Fuels ». Dans ASME 2009 3rd International Conference on Energy Sustainability collocated with the Heat Transfer and InterPACK09 Conferences. ASMEDC, 2009. http://dx.doi.org/10.1115/es2009-90182.

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Simulations have shown that it should be possible (within a relatively short time frame) to profitably synthesize high-purity carbon-neutral ethanol, gasoline, jet fuel, propylene, and many other hydrocarbons, in volumes that cannot be matched by any other renewable avenue, from captured CO2, water, and cheap off-peak low-carbon energy, notably form wind farms. The process, dubbed WindFuels, requires no biomass, and it is expected to solve the grid stability and energy storage challenges of wind energy. The process is based largely on the commercially proven technologies of wind energy, water electrolysis, and Fischer Tropsch Synthesis (FTS) chemistry. Wind energy is used to electrolyze water into hydrogen and oxygen. Some of the hydrogen is used in a process, the so-called reverse water gas shift (RWGS) reaction, that reduces CO2 to carbon monoxide (CO) and water. The CO and the balance of the hydrogen are fed into an FT reactor, similar to that commonly used to produce fuels and chemicals from coal or natural gas. Improved sub-processes have been simulated in detail, and key experiments will soon be carried out to help optimize process conditions. Conversion efficiencies (from input electrical to output chemical) are expected to approach 60%. Putting renewable hydrogen into liquid fuels solves the distribution and storage problems that have beset utilization of hydrogen in vehicles. Converting CO2 into fuels can eliminate the need for CO2 sequestration and reduce global CO2 emissions by 40% by mid-century. The amount of water needed for the renewable FTS (RFTS) process is an order of magnitude less than needed for biofuels. The atmosphere will eventually provide an unlimited source for CO2, though initially the CO2 would come from ammonia plants, biofuel refineries, cement factories, fossil power plants, and ore refineries. When the input energy is from off-peak wind and reasonable monetary credit is included for climate benefit, WindFuels could compete when petroleum is as low as $45/bbl.

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Bai, Shixun, Jan Kubelka et Mohammad Piri. « Toward the Rational Design of Chemical Formulations for EOR from Carbonates : Molecular–Level Understanding of Carbonate Wettability and its Reversal by Surfactants and Ions ». Dans Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/207340-ms.

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Abstract Wettability is a key factor influencing oil production, particularly from the oil-wet carbonate reservoirs where the recoveries are often low. This is a serious problem for the oil industry as significant portion of the world's hydrocarbon reserves resides in carbonate formations. Since the wettability has its roots in the inter-molecular interactions between the oil and the mineral, our objectives are, first, to provide the molecular-level understanding of the carbonate wettability and, second, to apply this understanding to devise effective approaches for wettability alteration. Specifically, we focused on chemical additives such as surfactants and ions, which have demonstrated potential as wettability reversal agents. Molecular dynamics (MD) simulations were used as the primary method to study the wettability properties on newly-developed model calcite and dolomite surfaces that mimic experimentally-known mineral properties. Wettability reversal by cationic, anionic, and non-ionic surfactants, as well as by divalent ions (Ca2+, Mg2+, and SO42-) were investigated. A systematic approach for maximizing the surfactant efficiency by tuning the cationic surfactant head-group chemistry was proposed. To validate the MD simulation results, experimental contact angle measurements on dolomite chips were conducted. The MD simulation results demonstrated that, in the absence of asphaltenes, the oil-wetness of the carbonate minerals arises from the electrostatic attraction between the (negatively charged) oil carboxylates and the (positive) surfaces. Due to this electrostatic nature, the wettability could be reversed only by the cationic (positive) surfactants, which screen the oil-surface attraction. Other surfactant types had negligible effect, in agreement with the experimental contact angle measurements. Moreover, the wettability alteration efficiency of the cationic surfactants was directly related to their molecular charge distributions, offering guidelines for the practical design of the most potent wettability-reversing molecules. The simulations of the wettability alteration by Mg2+, Ca2+, and SO42- ions were likewise consistent with the contact angle measurements. The roles of individual ions in the multiple ion exchange (MIE) mechanism were deduced, and the known strong temperature dependence of their wettability alteration effect explained by the stability of the ion hydration shells. Finally, the simulations also exposed differences between the wettability reversal mechanisms on calcite and dolomite minerals, which may have important practical impact. Our results offer a novel perspective on the carbonate wettability and its reversal from the standpoint of atomic-level interactions and molecular mechanisms. New models for the carbonate surfaces were developed for reliable simulations of the wetting properties, which led to new insights into the origins of carbonate oil-wetness and the mechanisms of its reversal in two types of minerals. Lastly, the MD simulations demonstrated their utility as a powerful tool for the practical design and evaluation of potential chemical agents for EOR from carbonate reservoirs.

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González, Lina M., Warren C. Ruder, William C. Messner et Philip R. LeDuc. « Sensing of Local, Highly Concentrated Magnetic Field Gradients in Magnetotactic Bacteria Induces Motility Reversal ». Dans ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80447.

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Many motile unicellular organisms have evolved specialized behaviors for detecting and responding to chemical gradients (chemotaxis) or oxygen (aerotaxis), while magnetotactic bacteria sense magnetic fields to align their direction of movement. Herein we show that Magnetospirillum magneticum (AMB-1) have the ability to sense and respond not only to the direction of magnetic fields of naturally occurring magnitude, but also to local, highly concentrated magnetic field gradients that do not occur in their natural environment. We imposed these gradients through our system integrating Helmholtz coils and permalloy (Ni80Fe20) microstructures. The AMB-1 exhibit three distinct behaviors as they approached gradients near the microstructures—unidirectional, single direction reversal, and double direction reversal. These results indicate previously unknown capabilities of the magnetic sensing systems of AMB-1.

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Rapports d'organisations sur le sujet "Chemical reverse approach"

Husson, Scott M., Viatcheslav Freger et Moshe Herzberg. Antimicrobial and fouling-resistant membranes for treatment of agricultural and municipal wastewater. United States Department of Agriculture, janvier 2013. http://dx.doi.org/10.32747/2013.7598151.bard.

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This research project introduced a novel membrane coating strategy to combat biofouling, which is a major problem for the membrane-based treatment of agricultural and municipal wastewaters. The novelty of the strategy is that the membrane coatings have the unique ability to switch reversibly between passive (antifouling) and active (antimicrobial) fouling control mechanisms. This dual-mode approach differs fundamentally from other coating strategies that rely solely on one mode of fouling control. The research project had two complementary objectives: (1) preparation, characterization, and testing of dual-mode polymer nanolayers on planar surfaces and (2) evaluation of these nanolayers as membrane modifiers. The first objective was designed to provide a fundamental understanding of how polymer nanolayer chemistry and structure affect bacterial deposition and to demonstrate the reversibility of chemical switching. The second objective, which focused on membrane development, characterization, and testing, was designed to demonstrate methods for the production of water treatment membranes that couple passive and active biofouling control mechanisms. Both objectives were attained through synergistic collaboration among the three research groups. Using planar silicon and glass surfaces, we demonstrated using infrared spectroscopy that this new polymer coating can switch reversibly between the anti-fouling, zwitterion mode and an anti-microbial, quaternary amine mode. We showed that switching could be done more than 50 times without loss of activity and that the kinetics for switching from a low fouling zwitterion surface to an antimicrobial quaternary amine surface is practical for use. While a low pH was required for switching in the original polymer, we illustrated that by slightly altering the chemistry, it is possible to adjust the pH at which the switching occurs. A method was developed for applying the new zwitterionic surface chemistry onto polyethersulfone (PES) ultrafiltration membranes. Bacteria deposition studies showed that the new chemistry performed better than other common anti-fouling chemistries. Biofilm studies showed that PESultrafiltration membranes coated with the new chemistry accumulated half the biomass volume as unmodified membranes. Biofilm studies also showed that PES membranes coated with the new chemistry in the anti-microbial mode attained higher biofilm mortality than PES membranes coated with a common, non-switchablezwitterionic polymer. Results from our research are expected to improve membrane performance for the purification of wastewaters prior to use in irrigation. Since reduction in flux due to biofouling is one of the largest costs associated with membrane processes in water treatment, using dual-mode nanolayer coatings that switch between passive and active control of biofouling and enable detachment of attached biofoulants would have significant economic and societal impacts. Specifically, this research program developed and tested advanced ultrafiltration membranes for the treatment of wastewaters. Such membranes could find use in membrane bioreactors treating municipal wastewater, a slightly upgraded version of what presently is used in Israel for irrigation. They also may find use for pretreatment of agricultural wastewaters, e.g., rendering facility wastewater, prior to reverse osmosis for desalination. The need to desalinate such impaired waters water for unlimited agricultural use is likely in the near future.

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