Academic literature on the topic 'Reaction range investigation'
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Journal articles on the topic "Reaction range investigation"
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Artun, Ozan. "Investigation of the production of cobalt-60 via particle accelerator." Nuclear Technology and Radiation Protection 32, no. 4 (2017): 327–33. http://dx.doi.org/10.2298/ntrp1704327a.
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The production process of cobalt-60 was simulated by a particle accelerator in the energy range of 5 to 100 MeV, particle beam current of 1 mA, and irradiation time of 1 hour to perform yield, activity of reaction, and integral yield for charged particle-induced reactions. Based on nuclear reaction processes, the obtained results in the production process of cobalt-60 were also discussed in detail to determine appropriate target material, optimum energy ranges, and suitable reactions.
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Ercan, Yildız. "Investigation of 54Fe(, n)57Ni Reaction for Low Activation Material Fe." Journal of Biomedical Research & Environmental Sciences 2, no. 9 (2021): 826–29. https://doi.org/10.37871/jbres1316.
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In fusion reactors, radioactivity can be controlled by effective material selection. Material selection is always important for effi cient conversion of radioactivity to electrical energy.The selection of structural materials provides more effi cient use of these structural materials with the results obtained from nuclear reactions. Low activation materials not only high in structural material performance and longer life, but also minimize related problems. Iron is an important element in fusion reactor technologies and astrophysical applications. For this reason, we obtained the theoretical cross-section values of the 54Fe(α, n)57Ni reaction in the range of 5-15 MeV (Mega electron volt) in this study. TALYS 1.8 (nuclear model code system) and NON-SMOKER (computer code) were used for theoretical calculations. Astrophysical S-factor values describing reactions at low energies were also calculated. In addition, reaction rate values were calculated with TALYS 1.8 and compared with EXFOR (experimental nuclear reaction data).
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Chen, Wenwu, Jianhan Liang, Lin Zhang, and Qingdi Guan. "A Numerical Investigation of Mixing Models in LES-FMDF for Compressible Reactive Flows." Energies 14, no. 16 (2021): 5180. http://dx.doi.org/10.3390/en14165180.
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The filtered mass density function (FMDF) model has been employed for large-eddy simulations (LES) of compressible high-speed turbulent mixing and reacting flows. However, the mixing model remains a pressing challenge for FMDF methods, especially for compressible reactive flows. In this work, a temporal development mixing layer with two different convective Mach numbers, Mc=0.4 and Mc=0.8, is used to investigate the mixing models. A simplified one-step reaction and a real hydrogen/air reaction are employed to study the mixing and turbulence-chemistry interaction. Two widely used mixing models, interaction by exchange with the mean (IEM) and Euclidean minimum spanning tree (EMST), are studied. Numerical results indicate that no difference is observed between the IEM and EMST models in simple reaction flows. However, for hydrogen/air reactions, the EMST model can predict the reaction more accurately in high-speed flow. For mixing models in compressible reactive flows, the requirement of localness preservation tends to be more essential as the convective Mach number increases. With the increase of compressibility, the sensitivity of the mixing model coefficient is reduced significantly. Therefore, the appropriate mixing model coefficient has a wider range. Results also indicate that a large error may result when using a fixed mixing model coefficient in compressible flows.
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Yildiz, Ercan, та Saniye Tekerek. "Investigation of 54Fe(α, n)57Ni Reaction for Low Activation Material Fe". Journal of Biomedical Research & Environmental Sciences 2, № 9 (2021): 826–29. http://dx.doi.org/10.37871/jbres1316.
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In fusion reactors, radioactivity can be controlled by effective material selection. Material selection is always important for efficient conversion of radioactivity to electrical energy.The selection of structural materials provides more efficient use of these structural materials with the results obtained from nuclear reactions. Low activation materials not only high in structural material performance and longer life, but also minimize related problems. Iron is an important element in fusion reactor technologies and astrophysical applications. For this reason, we obtained the theoretical cross-section values of the 54Fe(α, n)57Ni reaction in the range of 5-15 MeV (Mega electron volt) in this study. TALYS 1.8 (nuclear model code system) and NON-SMOKER (computer code) were used for theoretical calculations. Astrophysical S-factor values describing reactions at low energies were also calculated. In addition, reaction rate values were calculated with TALYS 1.8 and compared with EXFOR (experimental nuclear reaction data).
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Biran, Adi, Tomer Sapar, Ludmila Abezgauz, and Yaniv Edery. "Experimental investigation of the interplay between transverse mixing and pH reaction in porous media." Hydrology and Earth System Sciences 28, no. 20 (2024): 4755–70. http://dx.doi.org/10.5194/hess-28-4755-2024.
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Abstract. pH-induced reactive transport in porous environments is a critical factor in Earth sciences, influencing a range of natural and anthropogenic processes, such as mineral dissolution and precipitation, adsorption and desorption, microbial reactions, and redox transformations. These processes, pivotal to carbon capture and storage (CCS) applications to groundwater remediation, are determined by pH transport. However, the uncertainty in these macroscopic processes’ stems from pore-scale heterogeneities and the high diffusion value of the ions and protons forming the pH range. While practical for field-scale applications, traditional macroscopic models often fail to accurately predict experimental and field results in reactive systems due to their inability to capture the details of the pore-scale pH range. This study investigates the interplay between transverse mixing and pH-driven reactions in porous media. It focuses on how porous structure and flow rate affect mixing and chemical reaction dynamics. Utilizing confocal microscopy, the research visualizes fluorescently labeled fluids, revealing variations in mixing patterns from diffusive in homogeneous to shear-driven in heterogeneous media. However, pH-driven reactions show a different pattern, with a faster reaction rate, suggesting quicker pH equilibration between co-flowing fluids than predicted by transverse dispersion or diffusion. The study highlights the unique characteristics of pH change in water, which significantly influences reactive transport in porous media.
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BYSTRITSKY, V. M., V. M. GREBENYUK, S. S. PARZHITSKI, et al. "Experimental investigation of dd reaction in range of ultralow energies using Z-pinch." Laser and Particle Beams 18, no. 2 (2000): 325–33. http://dx.doi.org/10.1017/s0263034600182230.
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Experimental results on measurement of dd-reaction cross sections in the energy range of 0.1–1.5 keV using the Z-pinch technique are presented. The experiment was fulfilled at the high current generator of the High-Current Electronics Institute, city of Tomsk, Russia. The dd-fusion neutrons were registered by time-of-flight scintillator detectors and BF3 detectors of thermal neutrons. The estimates were obtained at 90% of the confidence level for the upper limits of the neutron-producing dd-reaction cross sections for average deuteron collision energies of 0.11, 0.34, 0.37, and 1.46 keV. These results substantiate feasibility to get a cross section magnitude for dd-reaction in the range of the collision energy of 0.8–3 keV using similar technology at the pulse current level of 2–3 MA.
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Yasunaga, N., S. Furukawa, Y. Kawaai, and J. Hirotsuji. "Investigation of radical reactions for efficiency improvement in ozone-hydrogen peroxide treatment." Water Science and Technology 43, no. 2 (2001): 205–12. http://dx.doi.org/10.2166/wst.2001.0091.
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It was verified by laboratory-scale experiments that the two-port ozone injection method was more advantageous for reaction efficiency in the ozone-hydrogen peroxide treatment than the conventional one-port ozone injection method under the condition of same ozone dose. The reason for this effectiveness was also investigated in detail by computer simulations in the wide range of the rate constant of OH radical reacting with TOC (kTOC). The laboratory-scale experiments revealed that the amount of TOC decomposed (δTOC) increased by up to 41% by the two-port injection method, indicating a 27% improvement in δO3/δTOC. A detailed investigation of these experimental results by computer simulations showed that by injecting ozone in two ports the amount of ozone consumed for the OH radical formation was increased more remarkably than that of ozone consumed for the radical chain reactions, and that the amount of OH radical reacting with TOC was increased more strikingly than that with ozone. Furthermore, it was found that the smaller the kTOC value within 105–109 M–1s–1 was, the more advantageous for the reaction efficiency the two-port injection method was.
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Artun, Ozan. "Investigation of production of samarium-151 and europium-152,154,155 via particle accelerator." Modern Physics Letters A 34, no. 20 (2019): 1950154. http://dx.doi.org/10.1142/s0217732319501542.
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This work aimed to investigate the production of [Formula: see text]Sm and [Formula: see text]Eu on natural Nd and Sm targets via particle accelerator because these radionuclides have the potential for use in nuclear battery technology such as betavoltaic batteries and radioisotope thermoelectric generators. Therefore, this work estimated cross-section curves for proton, deuteron, triton, helium-3, and alpha particles induced reactions in the energy range [Formula: see text]. The activities and products of yield were simulated for all reaction processes under selected conditions, the particle beam current of 1 mA and the irradiation time of 24 h. Moreover, to understand the formations of [Formula: see text] and [Formula: see text]Eu in the reaction processes, the appropriate energy region of the reactions by calculating the integral yield curves were determined. Based on the obtained results, determination of suitable targets, energy regions, and reaction processes were discussed by this work.
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Song, Jun, Jian Wang, and Li Wang. "Thermogravimetric Investigation of Calcium Oxalate." Advanced Materials Research 850-851 (December 2013): 160–63. http://dx.doi.org/10.4028/www.scientific.net/amr.850-851.160.
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The thermal properties of calcium oxalate were studied by means of TG analyzer. The factors such as heating rate, filling amounts of specimens and filling atmosphere etc., which may affect thermo gravimetric (TG) curves in TG analysis test were investigated. The results showed that, with the improving of heating rate, filling amounts of specimens and close packing, the starting reaction temperature was postponed more obviously and the width of reaction temperature range rises. The flow of the nitrogen gas enhanced heat transmission, caused the starting reaction temperature to shift to the low temperature zone, and it could also affect the response course. But the factors above didnt obviously influence the weightlessness of specimens.
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Tonev, R., and G. Dimova. "Investigation of chlorine wall decay in an old, decommissioned metallic pipe using a pipe section reactor." Water Supply 20, no. 3 (2020): 953–62. http://dx.doi.org/10.2166/ws.2020.017.
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Abstract The study investigates the kinetics of free chlorine depletion in tap water from the Sofia distribution network. The overall decay rates, the bulk reaction rate coefficient, the wall reaction rate coefficient and the influence of mass transfer have been determined in a laboratory pipe section reactor (PSR), testing an old decommissioned metallic pipe. In total, 23 series of experiments were performed under different initial free chlorine concentrations and different hydraulic conditions. The applicability of different chlorine decay mathematical models has been investigated. A new model was proposed, combining zero order bulk reactions and first order wall reactions, describing the laboratory results with Nash-Sutcliffe efficiency coefficients over 0.99. The obtained values for the wall reaction coefficient vary in the range 0.008–0.030 m/h, decreasing exponentially with increasing initial chlorine concentration.
Dissertations / Theses on the topic "Reaction range investigation"
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Dillon, Graham Keith. "Investigation of resonance phenomena in the '1'6O+'1'6O system." Thesis, University of York, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298323.
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Kreppel, Andrea [Verfasser], and Christian [Akademischer Betreuer] Ochsenfeld. "Quantum-chemical investigations of enzymatic reaction mechanisms and benchmarking of range-separated density-functional theory within the random phase approximation / Andrea Kreppel ; Betreuer: Christian Ochsenfeld." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1227188528/34.
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Millhoff, Catrin [Verfasser], Jens [Akademischer Betreuer] Rowold, and Andreas [Gutachter] Engelen. "Instrumental leadership and organizational change : a three-study investigation on the influence of instrumental leadership on employees’ change reactions within the framework of the extended full-range of leadership model / Catrin Millhoff ; Gutachter: Andreas Engelen ; Betreuer: Jens Rowold." Dortmund : Universitätsbibliothek Dortmund, 2019. http://d-nb.info/1219302198/34.
Full textBooks on the topic "Reaction range investigation"
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Fox, G. T. Customer Reviews/Feedback Investigation of the consumer reaction to the Adidas "Feet you wear" product range. Oxford Brookes University, 1998.
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Perdomo, Mauricio Canal. Full-range static reactive power compensator: A theoretical and experimental investigation into the use of static compensators - - -. 1987.
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Keegan, James, and Charles D. Deakin. Pathophysiology and management of anaphylaxis in the critically ill. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0314.
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Anaphylaxis is a severe life-threatening systemic hypersensitivity reaction, which occurs in approximately 10–20 per 100,000 population per annum, and accounts for 0.3% of adult critical care admissions. Anaphylaxis most commonly results from an exaggerated immune reaction to foreign antigens, prompting release of vasoactive substances from mast cells. A broad range of agents including foods, insect stings, latex, and drugs can trigger anaphylaxis. Common food allergens include nuts, shellfish, milk, and eggs. The most frequently implicated drugs include neuromuscular blocking agents (NMBAs) and antibiotics. The clinical features of anaphylaxis are variable and may occur together or in isolation. Epinephrine is the primary treatment for anaphylaxis, administered via the intramuscular route. Measurement of mast cell tryptase is essential for the diagnosis of anaphylaxis. Samples should be taken immediately, at 1–2 hours, and at 24 hours after the onset of symptoms. Investigations should be directed at identification of the trigger agent, and patients should be provided with information to enable them to avoid probable triggers and recognize future episodes.
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Herrstrom, David S. Light as Experience and Imagination from Medieval to Modern Times. The Rowman & Littlefield Publishing Group, 2022. https://doi.org/10.5040/9781683935407.
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In Light as Experience and Imagination from Medieval to Modern Times, David S. Herrstrom synthesizes and interprets the experience of light as revealed in a wide range of art and literature from medieval to modern times. The true subject of the book is making sense of the individual’s relationship with light, rather than the investigation of light’s essential nature, while telling the story of light “seducing” individuals from the Middle Ages to our modern times. Consequently, it is not concerned with the “progress” of scientific inquiries into the physical properties and behavior of light (optical science), but rather with subjective reactions as reflected in art, architecture, and literature. Instead of its evolution, this book celebrates the complexity of our relation to light’s character. No individual experience of light being “truer” than any other.
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Churchman, GJ, RW Fitzpatrick, and RA Eggleton, eds. Clays: Controlling the Environment. CSIRO Publishing, 1995. http://dx.doi.org/10.1071/9780643104969.
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Proceedings of the 10th International Clays Conference, Adelaide, Australia, July 18 to 23, 1993.
 Clays have provided us with the most active ingredients in soils, with building materials, with pottery and ceramics for both utility and decoration, and with coatings and fillers for paper, among other uses. The unique properties of these apparently everyday materials are being studied and used in an increasing range of industrial and environmental applications.
 Clays: Controlling the Environment provides a valuable compendium of the latest results from the complete range of clay-related scientific research. It includes coverage of the economic and environmental issues as well as directions for further research and development in many vital and expanding industries. All papers in these proceedings were subject to peer review. 
 The topics discussed are:
 
 
 Clays in industry and the environment
 Surface and interlayer reactions
 Clay mineral structures and chemistry
 Methods of investigation
 Clays in geology
 Soil mineralogy
 
 
 The emphasis of this book reflects the vital role that clays play in controlling natural, polluted and technological environments.
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Ufimtseva, Nataliya V., Iosif A. Sternin, and Elena Yu Myagkova. Russian psycholinguistics: results and prospects (1966–2021): a research monograph. Institute of Linguistics, Russian Academy of Sciences, 2021. http://dx.doi.org/10.30982/978-5-6045633-7-3.
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The monograph reflects the problems of Russian psycholinguistics from the moment of its inception in Russia to the present day and presents its main directions that are currently developing. In addition, theoretical developments and practical results obtained in the framework of different directions and research centers are described in a concise form. The task of the book is to reflect, as far as it is possible in one edition, firstly, the history of the formation of Russian psycholinguistics; secondly, its methodology and developed methods; thirdly, the results obtained in different research centers and directions in different regions of Russia; fourthly, to outline the main directions of the further development of Russian psycholinguistics. There is no doubt that in the theoretical, methodological and applied aspects, the main problems and the results of their development by Russian psycholinguistics have no analogues in world linguistics and psycholinguistics, or are represented by completely original concepts and methods. We have tried to show this uniqueness of the problematics and the methodological equipment of Russian psycholinguistics in this book. The main role in the formation of Russian psycholinguistics was played by the Moscow psycholinguistic school of A.A. Leontyev. It still defines the main directions of Russian psycholinguistics. Russian psycholinguistics (the theory of speech activity - TSA) is based on the achievements of Russian psychology: a cultural-historical approach to the analysis of mental phenomena L.S. Vygotsky and the system-activity approach of A.N. Leontyev. Moscow is the most "psycholinguistic region" of Russia - INL RAS, Moscow State University, Moscow State Linguistic University, RUDN, Moscow State Pedagogical University, Moscow State Pedagogical University, Sechenov University, Moscow State University and other Moscow universities. Saint Petersburg psycholinguists have significant achievements, especially in the study of neurolinguistic problems, ontolinguistics. The most important feature of Russian psycholinguistics is the widespread development of psycholinguistics in the regions, the emergence of recognized psycholinguistic research centers - St. Petersburg, Tver, Saratov, Perm, Ufa, Omsk, Novosibirsk, Voronezh, Yekaterinburg, Kursk, Chelyabinsk; psycholinguistics is represented in Cherepovets, Ivanovo, Volgograd, Vyatka, Kaluga, Krasnoyarsk, Irkutsk, Vladivostok, Abakan, Maikop, Barnaul, Ulan-Ude, Yakutsk, Syktyvkar, Armavir and other cities; in Belarus - Minsk, in Ukraine - Lvov, Chernivtsi, Kharkov, in the DPR - Donetsk, in Kazakhstan - Alma-Ata, Chimkent. Our researchers work in Bulgaria, Hungary, Vietnam, China, France, Switzerland. There are Russian psycholinguists in Canada, USA, Israel, Austria and a number of other countries. All scientists from these regions and countries have contributed to the development of Russian psycholinguistics, to the development of psycholinguistic theory and methods of psycholinguistic research. Their participation has not been forgotten. We tried to present the main Russian psycholinguists in the Appendix - in the sections "Scientometrics", "Monographs and Manuals" and "Dissertations", even if there is no information about them in the Electronic Library and RSCI. The principles of including scientists in the scientometric list are presented in the Appendix. Our analysis of the content of the resulting monograph on psycholinguistic research in Russia allows us to draw preliminary conclusions about some of the distinctive features of Russian psycholinguistics: 1. cultural-historical approach to the analysis of mental phenomena of L.S.Vygotsky and the system-activity approach of A.N. Leontiev as methodological basis of Russian psycholinguistics; 2. theoretical nature of psycholinguistic research as a characteristic feature of Russian psycholinguistics. Our psycholinguistics has always built a general theory of the generation and perception of speech, mental vocabulary, linked specific research with the problems of ontogenesis, the relationship between language and thinking; 3. psycholinguistic studies of speech communication as an important subject of psycholinguistics; 4. attention to the psycholinguistic analysis of the text and the development of methods for such analysis; 5. active research into the ontogenesis of linguistic ability; 6. investigation of linguistic consciousness as one of the important subjects of psycholinguistics; 7. understanding the need to create associative dictionaries of different types as the most important practical task of psycholinguistics; 8. widespread use of psycholinguistic methods for applied purposes, active development of applied psycholinguistics. The review of the main directions of development of Russian psycholinguistics, carried out in this monograph, clearly shows that the direction associated with the study of linguistic consciousness is currently being most intensively developed in modern Russian psycholinguistics. As the practice of many years of psycholinguistic research in our country shows, the subject of study of psycholinguists is precisely linguistic consciousness - this is a part of human consciousness that is responsible for generating, understanding speech and keeping language in consciousness. Associative experiments are the core of most psycholinguistic techniques and are important both theoretically and practically. The following main areas of practical application of the results of associative experiments can be outlined. 1. Education. Associative experiments are the basis for constructing Mind Maps, one of the most promising tools for systematizing knowledge, assessing the quality, volume and nature of declarative knowledge (and using special techniques and skills). Methods based on smart maps are already widely used in teaching foreign languages, fast and deep immersion in various subject areas. 2. Information search, search optimization. The results of associative experiments can significantly improve the quality of information retrieval, its efficiency, as well as adaptability for a specific person (social group). When promoting sites (promoting them in search results), an associative experiment allows you to increase and improve the quality of the audience reached. 3. Translation studies, translation automation. An associative experiment can significantly improve the quality of translation, take into account intercultural and other social characteristics of native speakers. 4. Computational linguistics and automatic word processing. The results of associative experiments make it possible to reveal the features of a person's linguistic consciousness and contribute to the development of automatic text processing systems in a wide range of applications of natural language interfaces of computer programs and robotic solutions. 5. Advertising. The use of data on associations for specific words, slogans and texts allows you to predict and improve advertising texts. 6. Social relationships. The analysis of texts using the data of associative experiments makes it possible to assess the tonality of messages (negative / positive moods, aggression and other characteristics) based on user comments on the Internet and social networks, in the press in various projections (by individuals, events, organizations, etc.) from various social angles, to diagnose the formation of extremist ideas. 7. Content control and protection of personal data. Associative experiments improve the quality of content detection and filtering by identifying associative fields in areas subject to age restrictions, personal information, tobacco and alcohol advertising, incitement to ethnic hatred, etc. 8. Gender and individual differences. The data of associative experiments can be used to compare the reactions (and, in general, other features of thinking) between men and women, different social and age groups, representatives of different regions. The directions for the further development of Russian psycholinguistics from the standpoint of the current state of psycholinguistic science in the country are seen by us, first of all: in the development of research in various areas of linguistic consciousness, which will contribute to the development of an important concept of speech as a verbal model of non-linguistic consciousness, in which knowledge revealed by social practice and assigned by each member of society during its inculturation is consolidated for society and on its behalf; in the expansion of the problematics, which is formed under the influence of the growing intercultural communication in the world community, which inevitably involves the speech behavior of natural and artificial bilinguals in the new object area of psycholinguistics; in using the capabilities of national linguistic corpora in the interests of researchers studying the functioning of non-linguistic and linguistic consciousness in speech processes; in expanding research on the semantic perception of multimodal texts, the scope of which has greatly expanded in connection with the spread of the Internet as a means of communication in the life of modern society; in the inclusion of the problems of professional communication and professional activity in the object area of psycholinguistics in connection with the introduction of information technologies into public practice, entailing the emergence of new professions and new features of the professional ethos; in the further development of the theory of the mental lexicon (identifying the role of different types of knowledge in its formation and functioning, the role of the word as a unit of the mental lexicon in the formation of the image of the world, as well as the role of the natural / internal metalanguage and its specificity in speech activity); in the broad development of associative lexicography, which will meet the most diverse needs of society and cognitive sciences. The development of associative lexicography may lead to the emergence of such disciplines as associative typology, associative variantology, associative axiology; in expanding the spheres of applied use of psycholinguistics in social sciences, sociology, semasiology, lexicography, in the study of the brain, linguodidactics, medicine, etc. This book is a kind of summarizing result of the development of Russian psycholinguistics today. Each section provides a bibliography of studies on the relevant issue. The Appendix contains the scientometrics of leading Russian psycholinguists, basic monographs, psycholinguistic textbooks and dissertations defended in psycholinguistics. The content of the publications presented here is convincing evidence of the relevance of psycholinguistic topics and the effectiveness of the development of psycholinguistic problems in Russia.
Book chapters on the topic "Reaction range investigation"
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Kraus, Jakob, Simon Brehm, Cameliu Himcinschi, and Jens Kortus. "Structural and Thermodynamic Properties of Filter Materials: A Raman and DFT Investigation." In Multifunctional Ceramic Filter Systems for Metal Melt Filtration. Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-40930-1_5.
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AbstractThe contribution focuses on the accurate prediction of heat capacities for intermetallics, the estimation of reaction paths for coated and uncoated alumina foam filters in contact with metallic melts, and the investigation of thermally induced changes in various filters and filtercomponents. Density functional theory (DFT) was able to provide isobaric heat capacities for Al–Fe and Al–Fe-Si systems that outclassed the empirical Neumann–Kopp rule and matched the experimental values over a wide temperature range. Moreover, DFT calculations clarified that the formation of hercynite at the interface between alumina filters and steel melt was the result of a solid-state reaction involving high concentrations of FeO. Ex-situ Raman spectroscopy was used to compare carbon-bonded alumina filters using different bindersfrom Carbores®P to environmentally friendly lactose/tannin, as a function of heat treatment. For these carbon-bonded filters, the prominent D and G bands were used to confirm the existence of graphitization processes and determine the size of graphite clusters resulting from these processes. In order to investigate the pyrolysis processes occurring in selected binder constituents of the lactose/tannin filters, the evolution of Raman spectra with temperature was analyzed via in-situ measurements. Wherever it was appropriate, experimental Raman data were compared with DFT-simulated spectra. Further, Raman spectroscopy was used to study the thermally induced formation of metastable alumina, helping to understand the structural changes that take place during the transformation of boehmite (γ-AlO(OH)) to corundum (α-Al2O3) via metastable transition phases: γ-Al2O3, δ-Al2O3, and θ-Al2O3.
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Poliakoff, Ellen, and Emma Gowen. "Automatic Imitation of Hand Movements in Clinical and Neurodiverse Populations." In Automatic Imitation. Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-62634-0_12.
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AbstractAutomatic imitation is related to both motor and social-cognitive processes and hence is highly relevant to a range of clinical and neurodiverse populations including neurodegenerative, psychiatric or mental health, and neurodevelopmental conditions. In this chapter, we review investigations of automatic imitation of hand and arm movements in these populations. For many of the conditions reviewed, there are relatively small numbers of studies in the literature and/or existing studies only include relatively small participant numbers. There is, however, some evidence for intact automatic imitation in several conditions (Parkinson’s, Alzheimer’s, depression, autism). If automatic imitation is unimpaired, motor and behavioral interventions have the potential to capitalize on this. There are, however, reports from one or two studies of increased automatic imitation in schizophrenia and mirror-touch synesthesia and reduced automatic imitation in eating disorders, which warrant further investigation. The evidence in developmental coordination disorder and Tourette’s is more mixed. Moreover, altered top-down modulation of automatic imitation has been found in several studies of autism and in one study of schizophrenia. We discuss some of the methodological issues, such as the importance of the stimuli and instructions used in the tasks, as well as considering other factors such as co-morbidities. There are also challenges in accounting for reaction time differences and a range of analysis approaches, which ought to be constrained by pre-registered analysis plans in future research. Future studies ought to investigate top-down modulation in other conditions since this process is key to successful motor and social function.
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Ji, Changwei, Jianpu Shen, and Shuofeng Wang. "Numerical Investigation of Combustion Characteristics of the Port Fuel Injection Hydrogen-Oxygen Internal Combustion Engine Under the Low-Temperature Intake Condition." In Proceedings of the 10th Hydrogen Technology Convention, Volume 1. Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-99-8631-6_3.
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AbstractThe flammability limits of the hydrogen-oxygen mixture are extremely wide, and the ignition energy is low. Due to its excellent combustion properties, the hydrogen-oxygen mixture can be used as fuel in internal combustion engines (ICEs). However, the combustion of hydrogen-oxygen mixture is too intense, which results in limited research on its application in ICEs and is limited to low-temperature conditions in aerospace. This research aims to numerically discuss the coupling effects of equivalence ratio and ignition timing on the port fuel injection hydrogen-oxygen ICE under the low-temperature intake condition. The three-dimensional geometric model of a single-cylinder ICE was established using the CONVERGE software and validated against the mean in-cylinder pressure and reaction mechanism. The results indicate that adjusting equivalence ratio and ignition timing operating parameters is beneficial for controlling the temperature and pressure in the cylinder within a reasonable range during the total combustion process. In general, under the low-temperature intake condition, adopting a high equivalence ratio and optimal ignition timing strategy improve the combustion process and power performance of the port fuel injection hydrogen-oxygen ICE.
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Saccardi, Riccardo, and Fermin Sanchez-Guijo. "How Can Accreditation Bodies, Such as JACIE or FACT, Support Centres in Getting Qualified?" In The EBMT/EHA CAR-T Cell Handbook. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-94353-0_38.
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AbstractThe FACT-JACIE accreditation system is based on a standard-driven process covering all the steps of HSC transplant activity, from donor selection to clinical care. Since the first approval of the First Edition of the Standards in 1998, over 360 HSCT programmes or facilities have been accredited at least once, most of them achieving subsequent re-accreditations (Snowden et al. 2017). The positive impact of the accreditation process in the EBMT Registry has been well established (Gratwohl et al. 2014). Starting with version 6.1, the standards include new items specifically developed for other cellular therapy products, with special reference to immune effector cells (IECs). This reflects the rapid evolution of the field of cellular therapy, primarily (but not exclusively) through the use of genetically modified cells, such as CAR-T cells. FACT-JACIE standards cover a wide range of important aspects that can be of use for centres that aim to be accredited in their countries to provide IEC therapy. Notably, FACT-JACIE accreditation itself is a key (or even a prerequisite) condition in some countries for approval by health authorities to provide commercial CAR-T cell therapy and is also valued by pharmaceutical companies (both those developing clinical trials and those manufacturing commercial products), which also inspect the cell therapy programmes and facilities established at each centre (Yakoub-Agha et al. 2020). Interest in applying for FACT-JACIE accreditation that includes IEC therapeutic programmes is clearly increasing, from four applications in 2017 to 36 applications approved in 2019. The standards do not cover the manufacturing of such cells but include the chain of responsibilities when the product is provided by a third party (Maus and Nikiforow 2017). In any case, all the steps in the process in which the centre is involved (e.g., patient or donor evaluations, cell collection, cell reception, and storage) are covered by the standards, including the appropriate agreements with the internal partners, including the pharmacy department. In addition, from a clinical perspective, IECs may require special safety monitoring systems due to the high frequency of acute adverse events related to the massive immunological reaction against the tumour. Although examples and explanations are found in the standard manual, here, the special importance of identifying and managing cytokine release syndrome (CRS) should be emphasized, and the standards focus not on specific therapeutic algorithms but on ensuring that medical and nursing teams are sufficiently trained in the early detection of this and other potential complications (e.g., neurological complications). They also pay attention to the full-time availability within the institution and its pharmacy of the necessary medication to address complications and the capacitation and involvement of Intensive Care and Neurology Department professionals to provide urgent care if needed. Forthcoming cellular therapy products, currently under investigation, will show a wider range of risk profiles, therefore requiring product-specific risk assessment and consequent adaptation of the clinical procedures for different classes of products. The FACT-JACIE standards will continue to adapt to these future needs to assist centres in their achievement of optimal clinical outcomes.
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Martín-Moruno, Dolores. "Crisis? What Crisis? Making Humanitarian Crises Visible in the History of Emotions." In Making Humanitarian Crises. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-00824-5_1.
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AbstractThis introductory chapter carves out a space for the histories of emotions and the senses within humanitarian visual culture, by examining the performativity of images in the construction of humanitarian crises. To this end, it analyses how illustrated pamphlets, cinema talks, photographs, documentary films, graphic novels and virtual reality environments have mobilised the affective responses of audiences, thus creating transnational networks of solidarity from the nineteenth century to present-day society. Furthermore, it questions presentist conceptions of pain, compassion, sympathy and empathy, as well as that these emotions have been the natural reaction of spectators regarding the pain of others. The chapter concludes by showing the potential of investigating related conceptions of indignation, shame, rage and horror in order to advocate for a history of humanitarian experiences.
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Weidner, Anja, Alexander Schmiedel, Mikhail Seleznev, and Horst Biermann. "Influence of Internal Defects on the Fatigue Life of Steel and Aluminum Alloys in the VHCF Range." In Multifunctional Ceramic Filter Systems for Metal Melt Filtration. Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-40930-1_24.
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AbstractThis chapter concerns the influence of internal defects (i.e. nonmetallic inclusions, secondary phases and cast defects) on the fatigue lifetime of steel and aluminum alloys in the high cycle fatigue (HCF) and very high cycle fatigue (VHCF) regime. The detrimental effect of internal defects depends on multiple factors such as size, morphology, chemical composition, test temperature or position in the material. Specimens were tested after active and/or reactive melt filtration processes of the materials which served to influence the amount and size distribution of internal defects. Fatigue experiments up to 109 cycles were carried out using ultrasonic fatigue testing equipment. In addition, in situ methods, as e.g. full surface view thermography and acoustic emission (AE), were applied to study the processes of crack initiation and propagation, which finally lead to fatigue failure. Furthermore, the cyclically strained samples were subjected to fractographic analysis and the S–N-curves were discussed according to the characteristics of the crack-initiating defects. Based on these investigations, an enhanced knowledge about the correlation of internal defects on the materials’ fatigue strength enables a specific melt filtration strategy adjusted to the materials’ service conditions.
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Weidner, Anja, Ruben Wagner, Mikhail Seleznev, and Horst Biermann. "Analysis of Detrimental Inclusions in Steel and Aluminum." In Multifunctional Ceramic Filter Systems for Metal Melt Filtration. Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-40930-1_25.
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AbstractThis chapter presents results on the analysis of nonmetallic as well as intermetallic inclusions within a metal matrix. In both, steel and aluminum matrix these impurities cause detrimental effects during production as well as in service, e.g. under mechanical load. In steel, nonmetallic inclusions originate from the steelmaking process and range in the magnitude of ppm. In recycled aluminum alloys, iron-rich intermetallic phases exhibit a volume fraction in the range of percent caused by insufficient scrap separation. Both types of detrimental inclusions/precipitates were investigated within different materials such as case hardening steel, quenched and tempered steel as well as Al-Si cast alloy. In order to reduce the amount of impurities, the effects of appropriate crucible materials, reactive and active melt filtration and chemical composition of the used materials were studied. Therefore, extensive metallographic investigations on sections were conducted with optical microscopy, manual and automated scanning electron microscopy, focused ion beam preparation and transmission electron microscopy aiming to determine the compositions of inclusions and intermetallic phases. Focusing on the morphology of inclusions and intermetallic phases, experiments with electrolytic and chemical extraction as well as X-ray micro tomography were performed. The gained knowledge can be utilized to improve filtration and reduce volume fraction and size of nonmetallic inclusions and intermetallic phases. This enables the design of long-lasting and safe materials.
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Provan, Drew. "Infectious and tropical diseases." In Oxford Handbook of Clinical and Laboratory Investigation, edited by Drew Provan. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198766537.003.0005.
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This is a brief outline of the current clinical and laboratory investigations of patients suffering from infectious diseases, including those from the tropics. It includes clinical and epidemiological assessment of the patient with fever. The appropriate investigations are discussed and cover the wide range of organisms now found in clinical practice via parasitology, mycology, bacteriology, and virology. Understanding of the laboratory techniques available is important in order to guide their rational use and understand their limitations. The techniques range from traditional methods such as microscopy and culture to newer molecular techniques such as MALDI-TOF and nucleic acid detection polymerase chain reaction. The section on clinical investigation in action outlines the approach to the patient with pyrexia of unknown origin. The increasingly important and complex clinical and laboratory assessment of antimicrobial resistance is also outlined, including how the laboratory fits in with this agenda.
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Raff, Lionel, Ranga Komanduri, Martin Hagan, and Satish Bukkapatnam. "Configuration Space Sampling Methods." In Neural Networks in Chemical Reaction Dynamics. Oxford University Press, 2012. http://dx.doi.org/10.1093/oso/9780199765652.003.0008.
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In order to achieve the maximum accuracy in characterizing the PES and the associated force fields for an MD investigation, careful preparation of the database is an essential step in the process. The points that must be addressed include the following: 1. The total volume of configuration space is extremely large, and its size increases as the internal energy of the system rises. For example, consider a four-atom system. For this system, at least six internal coordinates must be specified to determine the spatial configuration of the molecular system. At a given internal energy, each of these six coordinates can span a continuous range of values from some minimum to some maximum. If each variable range is divided into 100 equal increments and the potential energy of the system computed by some ab initio method for all possible configurations of the system, a total of 1006or 1012 electronic structure calculations would need to be executed. This is clearly beyond the computational capabilities of any computational system currently in existence. Grid sampling methods can and have been used effectively for three atom systems. However, for more complex systems, it is essential that procedures be developed that permit the regions of configuration space that are important in the reaction dynamics to be identified. 2. Sampling methods usually should be optimized to produce a reasonably uniform density of data points in those regions of configuration space that are important in the dynamics. If this is not done and there are regions of very high point density and others with low point density, no fitting technique will function well. The parameters of the method will adjust themselves to fit regions of high density preferentially over those with low density even when the low-density regions may be more important in the dynamics. An exception to the need to have an approximately uniform density of points in the database occurs in regions where the potential gradient is large. In such regions, the density of points in the database will need to be larger than in regions in which the gradient is small.
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Korkmaz Fatih Cuneyd, Yigit Kenan, and Guzel Bulent. "Experimental Investigation of Sloshing in the Rectangular Tank Under the Hydrophobic Effect." In Technology and Science for the Ships of the Future. IOS Press, 2018. https://doi.org/10.3233/978-1-61499-870-9-299.
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Liquid sloshing causes ship tank's surface to be damaged. In this study, this phenomenon was analyzed experimentally in rectangular tank model. Partially filled tank has been experienced and it was excited at single frequency range by direction of sway. Experiments were carried out with uncoated and hydrophobic coated tank. Only one water level was chosen for demonstrate sloshing effects on the different tank surface parameters. Wave path, wave breaking and shape of wave during flip-through were cough by high speed camera images. Strain gages have also been implemented to lateral side of tank to show local reaction of structure by measuring liquid induce deformation. Besides that, all experiments have been repeated by changed surface parameters at two contrast lateral sides on tanks. The surface parameter has been modified by applying hydrophobic coat. The coated surfaces propose to increase degrees of the contact angle between water drop and structure surface. The comparisons have been conducted within considering the images and measured results in coated, non-coated surface at tank sloshing experiments. The results show that the hydrophobic surface decreased the sloshing force on lateral sides, wave propagated more splay and water couldn't reach the level of wave as non-coated surface.
Conference papers on the topic "Reaction range investigation"
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Pech-Canul, M. A., and L. P. Chi-Canul. "Investigation of the Inhibitive Effect of N-Phosphono-Methyl-Glycine on the Corrosion of Carbon Steel in Neutral Solutions by Electrochemical Techniques." In CORROSION 1998. NACE International, 1998. https://doi.org/10.5006/c1998-98222.
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Abstract Steady-state current-voltage curves for various disk rotation rates were combined with electrochemical impedance measurements in order to investigate the corrosion inhibition of carbon steel by N-phosphono-methyl-glycine (NPMG) /Zn2+ mixtures with a concentration ratio of 1:1 between NPMG and zinc cations, in a model water. The efficiency of the NPMG/Zn2+ combination increases with concentration in the range 10-100 ppm, and it acts as a mixed type inhibitor, affecting both the anodic and cathodic reactions. The corrosion behavior in all the metal/environments investigated is characterized by the formation of a 3-D porous layer which tends to hinder the diffusion of oxygen. Such layer consists of corrosion products in the blank solution and of corrosion products and/or inhibitors in the presence of the NPMG/Zn2+ mixture. The impedance response of such layers depends on inhibitor concentration, exposure time and rotation rate of the disk. From electrochemical impedance measurements it was found that the oxygen reduction reaction is under mixed activation-diffusion control. It was shown by both steady-state and impedance measurements that there is a significant effect of rotation speed on the anodic reaction.
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Srinivasa Rao, A. "Fundamental Investigation on the Kinetics of the Rust Removal by Hydroxyethane Diphosphonic Acid (HEDPA)." In CORROSION 2001. NACE International, 2001. https://doi.org/10.5006/c2001-01557.
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Abstract In order to evaluate the adaptability of hydroxyethane diphosphonic acid (HEDPA) as an environmentally benign alternative rust removal agent, a systematic investigation is being carried out. The effectiveness of HEDPA was thoroughly investigated as a function of acid concentration in the range 2-100 vol.% and at different temperatures in the temperature range 27 - 60°C. The results suggest that the acid HEDPA is very effective in the rust removal process. The rate of rust removal by HEDPA is strongly dependent on the acid concentration and the solution temperature. Once an optimum threshold is reached an increase in either the acid concentration and/or temperature has a negative effect on the reaction kinetics. While the rust was completely removed by the 2 vol.% HEDPA within 3 hours at 27°C, the rust removal was completed within 30 minutes of treatment at 60°C. Similarly, while, the complete rust removal by 2 vol.% HEDPA was noticed after 3 hours, 10 vol.% HEDPA required chemical treatment for 0.75 hours at 27°C. However, chemical treatment with as received 100 vol.% HEDPA did not dissolve even 20% of the rust after 6 hours and the rust removal at 60°C was <2 %. Chemical treatment of rusted steel samples with concentrated HEDPA solution (concentration range 5-100 vol.% HEDPA) has produced rust free steel samples with very rough surface topography. In addition, the chemical processing at higher temperatures (40 - 60°C) and higher HEDPA concentrations (5-100 vol.%) produced strong pungent smell and unpleasant cleaning environment. The most effective HEDPA concentration and temperature for the rust removal appears to be 2 - 4 vol.% and < 40°C respectively. The activation energy for the rust dissolution process also appears to increase with an increase in the acid concentration. However, it appears that the increase is not very significant for the concentrations in the range 2-4 vol% HEDPA (2 vol.% - activation energy 11 ± 1 kcal/mole; 3 vol.% - activation energy 12± 3 kcal/mole and 4 vol% - activation energy 14 ± 2 kcal/mole). The activation energies for rust dissolution by 5, 10 and 20 vol.% HEDPA were found to be 20, 28 and 32 kcal/mole respectively. Above, 20 vol% HEDPA concentrations, a semi-quantitative determined value for the activation energy is 2 ± 2 kcal/mole. Prolonged treatment of samples with HEDPA allows the deposition of the reaction products onto the cleaned sample surface. The reaction product contains a mixture of various higher order iron phosphates.
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Yan, L., R. Worthingham, and F. King. "Electrochemical Properties of X-65 Pipeline Steel in Dilute HCO3−/CO32− Solutions." In CORROSION 2010. NACE International, 2010. https://doi.org/10.5006/c2010-10298.
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Abstract In this study, the electrochemical behaviour of X65 pipeline steel was investigated in three dilute HCO3− solutions, i.e., 10 mM, 20 mM, and 50 mM, purged with 5% CO2/N2 or 100% CO2 to achieve the typical pH of the trapped water under a disbonded shielding coating, i.e., pH 5.5 to 7.5. The measurements of corrosion potential (Ecorr) showed that the free corrosion process of X65 carbon steel in dilute HCO3− solutions involves Fe – 2e− → Fe2+ as the anodic reaction coupled with H+ + e− → ½H2 as the cathodic reaction. The investigation of the anodic polarization behaviour of X65 carbon steel in dilution HCO3− solutions purged with N2 + 5% CO2 confirmed that the anodic reaction, Fe – 2e− → Fe2+, was under mixed diffusion-electrochemical control. The anodic Tafel slope displayed a value of ~60 mV/decade in the 10mM HCO3− solution. As the HCO3− concentration was increased from 10 mM to 50 mM, the anodic Tafel slope constantly increased from ~ 60 to ~ 90 mV/decade. Cathodic polarization curves displayed a current-peak region at the low cathodic polarization range, -0.95 V to -0.75 V, and a typical Tafel region at potentials beyond -0.95 V. The current-peak within the low cathodic polarization range could be due to the catalyzing effect of the partially oxidized surface on the hydrogen evolution reaction (HER), and this catalyzing effect was enhanced by increasing HCO3− concentration or/and pH. A high cathodic Tafel slope, i.e, ~ 200 mV/decade, was observed for the HER at E < -0.95 V.
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Deshmukh, Shrirang, Bruce Brown, and David Young. "Investigating the Mechanism and Intermediates of the Oxygen Reduction Reaction." In CONFERENCE 2025. AMPP, 2025. https://doi.org/10.5006/c2025-00534.
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Abstract The Oxygen Reduction Reaction (ORR) plays a crucial role in corrosion mechanisms and the operation of electrochemical energy devices, affecting both stability and efficiency. Despite extensive research, the exact mechanisms and intermediates involved in ORR continue to be subjects of study. The literature reports a range of intermediates and mechanisms, which can be complex and, at times, contradictory. This paper conducts a comprehensive literature review with a primary focus on ORR mechanisms on steel, while also examining platinum, gold, and carbon electrodes. Recent advancements in experimental techniques and theoretical modeling have improved our understanding of ORR, which is essential for corrosion science and energy conversion technologies. This review compiles and analyzes the existing literature on the ORR, focusing on its behavior across different electrodes, including platinum, gold and steel/iron. The study identifies key intermediates such as HO2-, O2-, H2O2, OOH, and OH through electrochemical measurements and in situ spectroscopic methods, mapping their formation and consumption. Understanding these ORR pathways and their interactions with other corrosion processes contributes to the refinement of predictive corrosion models.
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Wang, Weishuai, Naizhe Zhang, Xuegang Liu, and Feng Xie. "Experimental Investigation on the Gasification Kinetics of Irradiated A3-3 Matrix Graphite." In 2024 31st International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2024. http://dx.doi.org/10.1115/icone31-133398.
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Abstract Thermal treatment in the atmosphere of carbon dioxide is proved to be a more promising approach to selectively separate C-14, which contributes substantially to the radioactivity of irradiated graphite even after thousands of years, from the bulk of irradiated graphite. Some key factors such as the origin of graphite, the type of reactor and the atmosphere during treatment play significant roles in the thermal treatment. In this paper, irradiated A3-3 graphite was selected to study the gasification reaction kinetics in a range of CO2/Ar/CO gas mixtures. In the absence of CO, the results of gasification reaction rate in different CO2 partial pressure and temperature were presented. In the CO2/Ar/CO mixed gas, the gasification reaction rate in different CO partial pressure was also examined. According to the results of experimental studies, the activation energy value and pre-exponential factor of the global reaction and elementary reactions were obtained. As a conclusion, it is inferred that uniform gas-solid reactions occur on the surface of irradiated A3-3 matrix graphite particles within the temperature range of 975 to 1045°C. The results might be beneficial for the future design of thermal treatment for the selective separation of C-14 from irradiated A3-3 matrix graphite.
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Demers, Guthrie, and Ryan Milcarek. "Investigation of Propane Micro-Scale Thermal Partial Oxidation for Syngas Production." In ASME 2024 Power Conference. American Society of Mechanical Engineers, 2024. http://dx.doi.org/10.1115/power2024-137738.
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Abstract Solid oxide fuel cells have been explored as one method of high efficiency power generation with potential for zero emissions, but challenges remain with fuel flexibility, system integration and reforming. Recent research in micro-scale thermal partial oxidation has shown promise for high fuel flexibility as hydrocarbons are reformed into syngas (i.e., H2 and CO), which can then integrate directly with SOFCs to produce power. In this paper, propane fuel is mixed with air at different equivalence ratios and the partial oxidation reactions are investigated at different reactor wall temperatures and flow rates. This study is completed using a hydrogen burner, which results in a small residence time for the oxidation reaction. Thermal radiation generated from the reaction is captured using a camera and the exhaust gas is analyzed using a gas chromatograph. Mass flow controllers are used to control the volume flow rate of propane and air entering the heated reactor tube. Flame images are used to identify different reaction regimes (weak flame, normal flame, and flame with repetitive extinction and ignition) across the range of selected variables and to create a regime map. Gas chromatograph data is used to track concentrations of different gases such as hydrogen, carbon oxides, and other gases in the exhaust of the reaction. High ethylene concentrations are detected and the implications of this gas are discussed. The results from this study are compared to previous results for syngas production with propane as the fuel with larger residence times. Chemical equilibrium analysis is used to compare propane with other liquid and gaseous fuels for its ability to be used to produce syngas for SOFC applications.
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Kräupl, Stefan, and Aldo Steinfeld. "Experimental Investigation of a Vortex-Flow Solar Chemical Reactor for the Combined ZnO-Reduction and CH4-Reforming." In ASME 2001 Solar Engineering: International Solar Energy Conference (FORUM 2001: Solar Energy — The Power to Choose). American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/sed2001-164.
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Abstract The co-production of Zn and synthesis gas by the combined reduction of ZnO and reforming of CH4 has been performed using a vortex-flow chemical reactor in a high-flux solar furnace. The reactor operating temperature ranged between 1032 and 1481 K for an input solar power of 2.3 to 4.6 kW and mean solar flux intensities of 810 to 1609 kW/m2. The performance of the reactor was determined by conducting a complete mass and energy balance for the chemical process. The chemical conversion ranged between 83–100%. The thermal efficiency, defined as the portion of input solar power absorbed as sensible and process heat, was in the range 11–28%. The exergy efficiency for the closed cycle, defined as the ratio of the maximum amount of work that the products leaving the reactor could produce if were re-combined to the input solar power, was in the range 0.3–3.1%. Major sources of energy loss are re-radiation heat transfer through the reactor aperture, conduction heat transfer through the reactor walls, and the quenching of the reaction products.
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Chen, J., X. F. Peng, Y. G. Ju, and B. X. Wang. "Comparative Investigation of N-Heptane Droplet Ignition in High Temperature Convective Environments." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43196.
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A 2-D numerical model was proposed to investigate the ignition of liquid fuel droplets in convective environments at high temperature. This model employed a skeletal mechanism consisting of 34 reactive species and 56 elementary reactions, rather than one-step overall reaction as in normal 2-D droplet ignition models, because the skeletal mechanism for n-heptane reproduces ignition delay times at various temperatures and pressures reasonably well. In present investigation an emphasis was addressed on the comparative analysis of suitability of the model, particularly numerical simulations were compared with experiments available in the literature, or for N-heptane droplets ignition in the convective air at temperature in a range of 1100K∼1400K and velocity of 2m/s. The ignition delay time and ignition position were obtained using an ignition criterion based on OH radical mass fraction. The flame behavior after ignition was also studied comparatively. The agreement between numerical simulation and experiments is reasonably good.
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Mirzaee Kakhki, Iman, Majid Charmchi, and Hongwei Sun. "Computational Investigation of Gallium Nitrite Ammonothermal Crystal Growth." In ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/ht2013-17506.
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This paper presents a rigorous approach to the simulation of the GaN growth process, which involves dissolution kinetics, transport by thermal convection and crystallization kinetics. So far, a wide range of numerical efforts have been published which provide valuable information on the flow field and temperature distribution in the hydrothermal crystal growth processes; however, no research has attempted to model the mass transfer in the nutrient porous basket nor did they present a modeling of the nutrient/mineralizers/solvent chemical reactions. In addition, the rate of crystallization was not numerically considered in the model. This paper shows the feasibility of developing a robust numerical code based on models that accurately account for the rate of nutrient dissolution and crystallization kinetics. Numerical simulation results revealed that chemical reaction kinetics can directly affect the crystallization rate and is a dominant factor in this phenomenon.
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Rubini, Dylan, Nikolas Karefyllidis, Liping Xu, Budimir Rosic, and Elina Nauha. "Decarbonisation of high-temperature endothermic chemical reaction processes using a novel turbomachine: robustness of the concept to feed variability." In GPPS Hong Kong24. GPPS, 2023. http://dx.doi.org/10.33737/gpps23-tc-245.
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This paper presents a revolutionary turbomachinery concept, referred to as the turbo-reactor, which has the potential to replace gas-fired radiant furnaces and decarbonise a wide range of hard-to-abate, high-temperature endothermic chemical reaction processes. While previous studies by the authors have confirmed the feasibility of using a turbo-reactor for steam cracking reactions, the numerical investigation presented in this work demonstrates its potential for eliminating emissions from a variety of energy-intensive chemical processes, including those used in the hydrogen industry. This step change in technology could be the catalyst needed to enable rapid scale-up of low-carbon hydrogen technology. The innovative design of the turbo-reactor is fundamentally based on converting all the mechanical energy imparted into internal energy, rather than pressure. This enables temperatures of up to 1700 ◦C (depending on fluid properties) to be achieved within an axial length in the order of one metre, resulting in a 100 – 1000Å~increase in power density compared to a surface heat exchanger. This paper presents the first comprehensive analysis of the turbo-reactor’s robustness and controllability across a broad spectrum of feeds, chemical reaction stages, Mach number regimes, and operating points, conclusively demonstrating the feasibility of a universal stage design strategy for various endothermic reaction processes.
Reports on the topic "Reaction range investigation"
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Sheyor, Ran. Investigation of Proton-Proton Short-Range Correlations via the 12C(e,e'pp) Reaction. Office of Scientific and Technical Information (OSTI), 2007. http://dx.doi.org/10.2172/955696.
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Smith, Donald L. Observations on the Effects of 252Cf Spontaneous-Fission Neutron Spectrum Uncertainties on Uncertainties in Calculated Spectrum-Average Cross Sections for Reactions in the Neutron Dosimetry Library IRDFF-II. IAEA Nuclear Data Section, 2022. http://dx.doi.org/10.61092/iaea.wx80-dm11.
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The Neutron Dosimetry Library IRDFF-II was released in January 2020, and was subsequently documented by an article published in the Nuclear Data Sheets by A. Trkov et al. The development of this library, under the auspices of the IAEA Nuclear Data Section, entailed extensive effort to assemble and examine the available, relevant experimental data, as well as to select and validate the best available cross-section evaluations, for some 110 neutron reaction processes included in this library. Part of the validation process for this library entailed comparing experimental and evaluated differential cross-sections as well as corresponding integral cross sections for a variety of integral neutron spectra considered to be relevant for fission and fusion neutron dosimetry purposes. Prominent among these spectra is the well-known 252Cf spontaneous-fission (s.f.) neutron spectrum that is considered to be a standard for both IRDFF-II and the ENDF/B libraries. Experimental and calculated uncertainties for all these data were considered in this validation process. The evaluated 252Cf s.f. neutron spectrum, owing to the manner in which it was developed, is considered to be largely independent of the evaluated neutron reaction cross sections in both of these libraries. Therefore, the uncertainties in calculated spectrum-average cross sections (SACS) stemming from evaluated cross-section uncertainties are considered to be largely independent from the uncertainties in the evaluated 252Cf s.f. neutron-spectrum itself. The present investigation sought specifically to examine systematic behaviors for the uncertainties of calculated neutron reaction SACS in IRDFF-II due exclusively to uncertainties in the 252Cf spectrum. This work was enabled by the availability of extensive calculations performed and documented by A. Trkov during development of the IRDFF-II Library. It was observed from the present investigation that the 252Cf s.f. neutron spectrum component of these calculated SAC uncertainties, for threshold reactions that exhibit relatively smooth cross-section behaviors, vary quite smoothly and predictably as a function of the parameter E50% (that neutron energy at which the reaction-rate integral for this neutron spectrum reaches 50% of the integral over the full energy range) for values of E50% from around 2 MeV up to almost 17 MeV. The behaviors observed in the present investigation for those reactions in IRDFF-II involving lower and higher values of E50% are less predictable owing to factors that are discussed in this report. This report also provides numerous tables and plots based on calculated results from the work of A. Trkov to illustrate these conclusions.
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Lahav, Ori, Albert Heber, and David Broday. Elimination of emissions of ammonia and hydrogen sulfide from confined animal and feeding operations (CAFO) using an adsorption/liquid-redox process with biological regeneration. United States Department of Agriculture, 2008. http://dx.doi.org/10.32747/2008.7695589.bard.
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The project was originally aimed at investigating and developing new efficient methods for cost effective removal of ammonia (NH₃) and hydrogen sulfide (H₂S) from Concentrated Animal Feeding Operations (CAFO), in particular broiler and laying houses (NH₃) and hog houses (H₂S). In both cases, the principal idea was to design and operate a dedicated air collection system that would be used for the treatment of the gases, and that would work independently from the general ventilation system. The advantages envisaged: (1) if collected at a point close to the source of generation, pollutants would arrive at the treatment system at higher concentrations; (2) the air in the vicinity of the animals would be cleaner, a fact that would promote animal growth rates; and (3) collection efficiency would be improved and adverse environmental impact reduced. For practical reasons, the project was divided in two: one effort concentrated on NH₃₍g₎ removal from chicken houses and another on H₂S₍g₎ removal from hog houses. NH₃₍g₎ removal: a novel approach was developed to reduce ammonia emissions from CAFOs in general, and poultry houses in particular. Air sucked by the dedicated air capturing system from close to the litter was shown to have NH₃₍g₎ concentrations an order of magnitude higher than at the vents of the ventilation system. The NH₃₍g₎ rich waste air was conveyed to an acidic (0<pH<~5) bubble column reactor where NH₃ was converted to NH₄⁺. The reactor operated in batch mode, starting at pH 0 and was switched to a new acidic absorption solution just before NH₃₍g₎ breakthrough occurred, at pH ~5. Experiments with a wide range of NH₃₍g₎ concentrations showed that the absorption efficiency was practically 100% throughout the process as long as the face velocity was below 4 cm/s. The potential advantages of the method include high absorption efficiency, lower NH₃₍g₎ concentrations in the vicinity of the birds, generation of a valuable product and the separation between the ventilation and ammonia treatment systems. A small scale pilot operation conducted for 5 weeks in a broiler house showed the approach to be technically feasible. H₂S₍g₎ removal: The main goal of this part was to develop a specific treatment process for minimizing H₂S₍g₎ emissions from hog houses. The proposed process consists of three units: In the 1ˢᵗ H₂S₍g₎ is absorbed into an acidic (pH<2) ferric iron solution and oxidized by Fe(III) to S⁰ in a bubble column reactor. In parallel, Fe(III) is reduced to Fe(II). In the 2ⁿᵈ unit Fe(II) is bio-oxidized back to Fe(III) by Acidithiobacillus ferrooxidans (AF).In the 3ʳᵈ unit S⁰ is separated from solution in a gravity settler. The work focused on three sub-processes: the kinetics of H₂S absorption into a ferric solution at low pH, the kinetics of Fe²⁺ oxidation by AF and the factors that affect ferric iron precipitation (a main obstacle for a continuous operation of the process) under the operational conditions. H₂S removal efficiency was found higher at a higher Fe(III) concentration and also higher for higher H₂S₍g₎ concentrations and lower flow rates of the treated air. The rate limiting step of the H₂S reactive absorption was found to be the chemical reaction rather than the transition from gas to liquid phase. H₂S₍g₎ removal efficiency of >95% was recorded with Fe(III) concentration of 9 g/L using typical AFO air compositions. The 2ⁿᵈ part of the work focused on kinetics of Fe(II) oxidation by AF. A new lab technique was developed for determining the kinetic equation and kinetic parameters (KS, Kₚ and mₘₐₓ) for the bacteria. The 3ʳᵈ part focused on iron oxide precipitation under the operational conditions. It was found that at lower pH (1.5) jarosite accumulation is slower and that the performance of the AF at this pH was sufficient for successive operation of the proposed process at the H₂S fluxes predicted from AFOs. A laboratory-scale test was carried out at Purdue University on the use of the integrated system for simultaneous hydrogen sulfide removal from a H₂S bubble column filled with ferric sulfate solution and biological regeneration of ferric ions in a packed column immobilized with enriched AFbacteria. Results demonstrated the technical feasibility of the integrated system for H₂S removal and simultaneous biological regeneration of Fe(III) for potential continuous treatment of H₂S released from CAFO. NH₃ and H₂S gradient measurements at egg layer and swine barns were conducted in winter and summer at Purdue. Results showed high potential to concentrate NH₃ and H₂S in hog buildings, and NH₃ in layer houses. H₂S emissions from layer houses were too low for a significant gradient. An NH₃ capturing system was designed and tested in a 100-chicken broiler room. Five bell-type collecting devices were installed over the litter to collect NH₃ emissions. While the air extraction system moved only 10% of the total room ventilation airflow rate, the fraction of total ammonia removed was 18%, because of the higher concentration air taken from near the litter. The system demonstrated the potential to reduce emissions from broiler facilities and to concentrate the NH₃ effluent for use in an emission control system. In summary, the project laid a solid foundation for the implementation of both processes, and also resulted in a significant scientific contribution related to AF kinetic studies and ferrous analytical measurements.
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Willis, C., F. Jorgensen, S. A. Cawthraw, et al. A survey of Salmonella, Escherichia coli (E. coli) and antimicrobial resistance in frozen, part-cooked, breaded or battered poultry products on retail sale in the United Kingdom. Food Standards Agency, 2022. http://dx.doi.org/10.46756/sci.fsa.xvu389.
Full textAbstract:
Frozen, breaded, ready-to-cook chicken products have been implicated in outbreaks of salmonellosis. Some of these outbreaks can be large. For example, one outbreak of Salmonella Enteritidis involved 193 people in nine countries between 2018 and 2020, of which 122 cases were in the UK. These ready-to-cook products have a browned, cooked external appearance, which may be perceived as ready-to-eat, leading to mishandling or undercooking by consumers. Continuing concerns about these products led FSA to initiate a short-term (four month), cross-sectional surveillance study undertaken in 2021 to determine the prevalence of Salmonella spp., Escherichia coli and antimicrobial resistance (AMR) in frozen, breaded or battered chicken products on retail sale in the UK. This study sought to obtain data on AMR levels in Salmonella and E. coli in these products, in line with a number of other FSA instigated studies of the incidence and nature of AMR in the UK food chain, for example, the systematic review (2016). Between the beginning of April and the end of July 2021, 310 samples of frozen, breaded or battered chicken products containing either raw or partly cooked chicken, were collected using representative sampling of retailers in England, Wales, Scotland and Northern Ireland based on market share data. Samples included domestically produced and imported chicken products and were tested for E. coli (including extended-spectrum beta-lactamase (ESBL)-producing, colistin-resistant and carbapenem-resistant E. coli) and Salmonella spp. One isolate of each bacterial type from each contaminated sample was randomly selected for additional AMR testing to determine the minimum inhibitory concentration (MIC) for a range of antimicrobials. More detailed analysis based on Whole Genome Sequencing (WGS) data was used to further characterise Salmonella spp. isolates and allow the identification of potential links with human isolates. Salmonella spp. were detected in 5 (1.6%) of the 310 samples and identified as Salmonella Infantis (in three samples) and S. Java (in two samples). One of the S. Infantis isolates fell into the same genetic cluster as S. Infantis isolates from three recent human cases of infection; the second fell into another cluster containing two recent cases of infection. Countries of origin recorded on the packaging of the five Salmonella contaminated samples were Hungary (n=1), Ireland (n=2) and the UK (n=2). One S. Infantis isolate was multi-drug resistant (i.e. resistant to three different classes of antimicrobials), while the other Salmonella isolates were each resistant to at least one of the classes of antimicrobials tested. E. coli was detected in 113 samples (36.4%), with counts ranging from <3 to >1100 MPN (Most Probable Number)/g. Almost half of the E. coli isolates (44.5%) were susceptible to all antimicrobials tested. Multi-drug resistance was detected in 20.0% of E. coli isolates. E. coli isolates demonstrating the ESBL (but not AmpC) phenotype were detected in 15 of the 310 samples (4.8%) and the AmpC phenotype alone was detected in two of the 310 samples (0.6%) of chicken samples. Polymerase Chain Reaction (PCR) testing showed that five of the 15 (33.3%) ESBL-producing E. coli carried blaCTX-M genes (CTX-M-1, CTX-M-55 or CTX-M-15), which confer resistance to third generation cephalosporin antimicrobials. One E. coli isolate demonstrated resistance to colistin and was found to possess the mcr-1 gene. The five Salmonella-positive samples recovered from this study, and 20 similar Salmonella-positive samples from a previous UKHSA (2020/2021) study (which had been stored frozen), were subjected to the cooking procedures described on the sample product packaging for fan assisted ovens. No Salmonella were detected in any of these 25 samples after cooking. The current survey provides evidence of the presence of Salmonella in frozen, breaded and battered chicken products in the UK food chain, although at a considerably lower incidence than reported in an earlier (2020/2021) study carried out by PHE/UKHSA as part of an outbreak investigation where Salmonella prevalence was found to be 8.8%. The current survey also provides data on the prevalence of specified AMR bacteria found in the tested chicken products on retail sale in the UK. It will contribute to monitoring trends in AMR prevalence over time within the UK, support comparisons with data from other countries, and provide a baseline against which to monitor the impact of future interventions. While AMR activity was observed in some of the E. coli and Salmonella spp. examined in this study, the risk of acquiring AMR bacteria from consumption of these processed chicken products is low if the products are cooked thoroughly and handled hygienically.
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Wongpiyabovorn, Jongkonnee, Nattiya Hirankarn, Yingyos Avihingsanon, Tewin Tencomnao, Yong Poovorawan, and Kriangsak Ruchusatsawat. The association between immunogenetics and genetic susceptibility of psoriasis in Thai population. Chulalongkorn University, 2006. https://doi.org/10.58837/chula.res.2006.27.
Full textAbstract:
Psoriasis is T-cell-mediated skin autoimmunity, required environmental triggers and genetic susceptibility factors to become manifested. Psoriasis is a chronic skin disease characterized by the abnormal hyperproliferation and differentiation of the epidermis, elongated and prominent blood vessels and a thick perivascular lymphocytic infiltrate. Vascular endothelial growth factor (VEGF) gene play important role in pathogenesis of various diseases with angiogenic basis such as breast cancer and autoimmune disease including psoriasis. Many studies analyzed the association of VEGF gene polymorphism in many positions in Caucasian and non-Caucasian. Most reports in some position that really point to important about single nucleotide polymorphism (SNP) with several autoimmune diseases including psoriasis. Although the precise causes of this auto-immune disease remain elusive. It appears to be influenced by stress. The serotonergic system known to depend primarily on the serotonin transporter (5-HTT) may have a role in psoriasis. The serotonin transporter-linked promoter region (5-HTTLPR) polymorphism occurred by insertion/deletion is evident to result in three different length alleles namely S, L as predominant variant alleles and XL as a rare one. These three alleles have 14, 16 and 18 or 20 repetitive DNA sequences, respectively and have been shown to associate with certain neuropsychiatric diseases. Although roles of serotonin and serotonin receptors in psoriasis were investigated, the impact of 5-HTTLPR on psoriasis has not been studied. Therefore, the 5-HTTLPR polymorphism was analyzed to assess whether these variants are associated with psoriasis. Furthermore, having recognized the relationship between oxidative stress and psoriasis, the association between G82S polymorphism in the gene encoding the receptor for advanced glycation end products (RAGE) and psoriasis was investigated. The aims of study, we determine the distribution of VEGF, RAGE and 5-HTTLPR polymorphism in Thai psoriasis patients. We analyzed SNPs within the VEGF (-1557) (C/A), -460(C/T) and +405(C/G)). G82S RAGE and 5-HTTLPR (S, L and XL) gene polymorphism. In population-based case-control study, allele and genotype frequencies of each marker were compared between 234 unrelated healthy volunteers and 154 chronic plapue psoriasis patients (102 early-onset and 52 late-onset psoriasis) for VEGF gene, one hundred seventy eight healthy donors and 134 psoriasis patients for RAGE gene and one hundred twenty seven healthy controls and 142 psoriasis patients for 5-HTTLPR gene. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and PCR-sequence specific primer (PCR-SSP) methods. The results, The -460 TT or CT compared to CC VEGF genotype were found to be significantly risk associated with early-onset psoriasis patients compared with healthy controls (p=0.0450, odds ratio (OR) =4.67, 95% confidence interval (CI) = 1.03-29.52). Interesthingly, haplotype analysis revealed that the CTG haplotype was found to be significantly associated with susceptibility to psoriasis and early-onset psoriasis compared with healthy controls (p=0.0460, OR=1.37, 95% CI=1.00-1.87, p=0.0163, OR=1.54, 95% CI=1.08-2.18, respectively). Moreover, VEGF plasma concentration was not significantly different between groups of haplotype in psoriasis patients. A significantly greater 82A G82S RAGE allele frequency was observed in psoriatic patients than in control subjects (p=0.001 OR=0.52 95% CI=0.35-0.78). Finally, the 5HTTPR polymorphism was no significant change in the allelic frequencies between psoriatic and control subjects (p=0.531, OR=1.15, 95% CI=0.78-1.70). Thus, the result demonstrated that the CTG haplotype and -460 C/T VEGF polymorphism may be used as a genetic marker for early-onset psoriasis in Thais but the 5-HTTLPR was not associated with psoriasis in Thai population. Furthermore, the G82S RAGE polymorphism was associated with psoriasis, and further investigations should be carried out to gain insights into its molecular mechanism in psoriasis.
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Cohen, Roni, Kevin Crosby, Menahem Edelstein, et al. Grafting as a strategy for disease and stress management in muskmelon production. United States Department of Agriculture, 2004. http://dx.doi.org/10.32747/2004.7613874.bard.
Full textAbstract:
The overall objective of this research was to elucidate the horticultural, pathological, physiological and molecular factors impacting melon varieties (scion) grafted onto M. cannonballus resistant melon and squash rootstocks. Specific objectives were- to compare the performance of resistant melon germplasm (grafted and non-grafted) when exposed to M. cannoballus in the Lower Rio Grande valley and the Wintergarden, Texas, and in the Arava valley, Israel; to address inter-species relationships between a Monosporascus resistant melon rootstock and susceptible melon scions in terms of fruit-set, fruit quality and yield; to study the factors which determine the compatibility between the rootstock and the scion in melon; to compare the responses of graft unions of differing compatibilities under disease stress, high temperatures, deficit irrigation, and salinity stress; and to investigate the effect of rootstock on stress related gene expression in the scion. Some revisions were- to include watermelon in the Texas investigations since it is much more economically important to the state, and also to evaluate additional vine decline pathogens Didymella bryoniae and Macrophomina phaseolina. Current strategies for managing vine decline rely heavily on soil fumigation with methyl bromide, but restrictions on its use have increased the need for alternative management strategies. Grafting of commercial melon varieties onto resistant rootstocks with vigorous root systems is an alternative to methyl bromide for Monosporascus root rot/vine decline (MRR/VD) management in melon production. Extensive selection and breeding has already produced potential melon rootstock lines with vigorous root systems and disease resistance. Melons can also be grafted onto Cucurbita spp., providing nonspecific but efficient protection from a wide range of soil-borne diseases and against some abiotic stresses, but compatibility between the scion and the rootstock can be problematic. During the first year experiments to evaluate resistance to the vine decline pathogens Monosporascus cannonballus, Didymella bryoniae, and Macrophomina phaseolina in melon and squash rootstocks proved the efficacy of these grafted plants in improving yield and quality. Sugars and fruit size were better in grafted versus non-grafted plants in both Texas and Israel. Two melons (1207 and 124104) and one pumpkin, Tetsukabuto, were identified as the best candidate rootstocks in Texas field trials, while in Israel, the pumpkin rootstock RS59 performed best. Additionally, three hybrid melon rootstocks demonstrated excellent resistance to both M. cannonballus and D. bryoniae in inoculated tests, suggesting that further screening for fruit quality and yield should be conducted. Experiments with ABA in Uvalde demonstrated a significant increase in drought stress tolerance and concurrent reduction in transplant shock due to reduced transpiration for ‘Caravelle’ plants. In Israel, auxin was implicated in reducing root development and contributing to increased hydrogen peroxide, which may explain incompatibility reactions with some squash rootstocks. However, trellised plants responded favorably to auxin (NAA) application at the time of fruit development. Gene expression analyses in Israel identified several cDNAs which may code for phloem related proteins, cyclins or other factors which impact the graft compatibility. Manipulation of these genes by transformation or traditional breeding may lead to improved rootstock cultivars. Commercial applications of the new melon rootstocks as well as the ABA and TIBA growth regulators have potential to improve the success of grafted melons in both Israel and Texas. The disease resistance, fruit quality and yield data generated by the field trials will help producers in both locations to decide what rootstock/scion combinations will be best.
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Droby, Samir, Joseph W. Eckert, Shulamit Manulis, and Rajesh K. Mehra. Ecology, Population Dynamics and Genetic Diversity of Epiphytic Yeast Antagonists of Postharvest Diseases of Fruits. United States Department of Agriculture, 1994. http://dx.doi.org/10.32747/1994.7568777.bard.
Full textAbstract:
One of the emerging technologies is the use of microbial agents for the control of postharvest diseases of fruits and vegetables. A number of antagonistic microorganisms have been discovered which have the potential to effectively control postharvest diseases. Some of this technology has been patented and commercial products such as AspireTM (Ecogen Corporatin, Langhorne, PA, USA), Biosave 10TM and Biosave 11TM (Ecoscience Inc., Worchester, MA, USA) have been registered for commercial use. The principal investigator of this project was involved in developing the yeast-based biofungicide-AspireTM and testing its efficacy under commercial conditions. This research project was initiated to fill the gap between the knowledge available on development and commercial implementation of yeast biocontrol agents and basic understanding of various aspects related to introducing yeast antagonists to fruit surfaces, along with verification of population genetics. The main objectives of this study were: Study ecology, population dynamics and genetic diversity of the yeast antagonists Candida guilliermondii, C. oleophila, and Debaryomyces hansenii, and study the effect of preharvest application of the yeast antagonist C. oleophila naturally occurring epiphytic microbial population and on the development of postharvest diseases of citrus fruit during storage. Our findings, which were detailed in several publications, have shown that an epiphytic yeast population of grapefruit able to grow under high osmotic conditions and a wide range of temperatures was isolated and characterized for its biocontrol activity against green mold decay caused by Penicillium digitatum. Techniques based on random amplified polymorphic DNA (RAPD) and arbitrary primed polymerase chain reaction (ap-PCR), as well as homologies between sequences of the rDNA internal transcribed spacers (ITS) and 5.8S gene, were used to characterize the composition of the yeast population and to determine the genetic relationship among predominant yeast species. Epiphytic yeasts exhibiting the highest biocontrol activity against P. digitatum on grapefruit were identified as Candida guilliermondii, C. oleophila, C. sake, and Debaryomyces hansenii, while C. guilliermondii was the most predominant species. RAPD and ap-PCR analysis of the osmotolerant yeast population showed two different, major groups. The sequences of the ITS regions and the 5.8S gene of the yeast isolates, previously identified as belonging to different species, were found to be identical. Following the need to develop a genetically marked strain of the yeast C. oleophila, to be used in population dynamics studies, a transformation system for the yeast was developed. Histidine auxotrophy of C. oloephila produced using ethyl methanesulfonate were transformed with plasmids containing HIS3, HIS4 and HIS5 genes from Saccharomyces cerevisiae. In one mutant histidin auxotrophy was complemented by the HIS5 gene of S. cerevisiae is functionally homologous to the HIS5 gene in V. oleophila. Southern blot analysis showed that the plasmid containing the S. cerevisiae HIS5 gene was integrated at a different location every C. oleophila HIS+ transformant. There were no detectable physiological differences between C. oleophila strain I-182 and the transformants. The biological control ability of C. oleophila was not affected by the transformation. A genetically marked (with b-glucuronidase gene) transformant of C. oleophila colonized wounds on orange fruits and its population increased under field conditions. Effect of preharvest application of the yeast C. oleophila on population dynamics of epiphytic microbial population on wounded and unwounded grapefruit surface in the orchard and after harvest was also studied. In addition, the effect of preharvest application of the yeast C. oleophila on the development of postharvest decay was evaluated. Population studies conducted in the orchard showed that in control, non-treated fruit, colonization of wounded and unwounded grapefruit surface by naturally occurring filamentous fungi did not vary throughout the incubation period on the tree. On the other hand, colonization of intact and wounded fruit surface by naturally occurring yeasts was different. Yeasts colonized wounded surface rapidly and increased in numbers to about two orders of magnitude as compared to unwounded surface. On fruit treated with the yeast and kept on the tree, a different picture of fungal and yeast population had emerged. The detected fungal population on the yeast-treated intact surface was dramatically reduced and in treated wounds no fungi was detected. Yeast population on intact surface was relatively high immediately after the application of AspireTM and decreased to than 70% of that detected initially. In wounds, yeast population increased from 2.5 x 104 to about 4x106 after 72 hours of incubation at 20oC. Results of tests conducted to evaluate the effect of preharvest application of AspireTM on the development of postharvest decay indicated the validity of the approach.