Academic literature on the topic 'Ozone synthesis efficiency'

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Journal articles on the topic "Ozone synthesis efficiency"

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Gibalov, Valentin I., Takaaki Murata, and Gerhard J. Pietsch. "Productivity and Efficiency of Ozone Synthesis in Coplanar Discharge Arrangements." Ozone: Science & Engineering 25, no. 5 (October 2003): 431–43. http://dx.doi.org/10.1080/01919510390481757.

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Kelly, F. J., and S. Birch. "Pulmonary Protein Synthesis Response to Ozone." Human & Experimental Toxicology 13, no. 6 (June 1994): 407–10. http://dx.doi.org/10.1177/096032719401300607.

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1 Exposure to either 800 or 1200 ppb ozone for 6 h did not influence the content or activity of mouse lung ribosomal RNA; in consequence pulmonary protein synthesis pathways were not altered. 2 Increasing the exposure period to 24 h had a marked effect on protein metabolism which depended on the dose of ozone employed. A dose of 800 ppb resulted in a 17% increase in lung protein content. Since both lung ribosomal capacity and fractional synthesis rates were unchanged at this time, it is concluded that both a lower ribosomal activity and an increased protein degradation rate were responsible for the decrease in content. 3 Exposure to 1200 ppb ozone for 24 h, paradoxically resulted in increases in both the fractional (33%) and total (19%) protein synthetic rates. These responses were due to an increased pulmonary ribosomal efficiency in the lung at this time. 4 We conclude that, in the short term, reduced pulmonary synthetic capacity is not a component of ozone-induced lung injury, but rather, this important component of the repair mechanism, can be up-regulated in response to lung injury.
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Li, Meng, Bin Zhu, Yan Yan, Tie Li, and Yi-Min Zhu. "A High-Efficiency Double Surface Discharge and Its Application to Ozone Synthesis." Plasma Chemistry and Plasma Processing 38, no. 5 (May 4, 2018): 1063–80. http://dx.doi.org/10.1007/s11090-018-9902-6.

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Krogh, Fabio, Reto Merz, Rudolf Gisler, Marco Müller, Bernhard Paolini, Jose L. Lopez, and Alfred Freilich. "Inhomogeneous feed gas processing in industrial ozone generation." Water Science and Technology 58, no. 11 (December 1, 2008): 2077–82. http://dx.doi.org/10.2166/wst.2008.760.

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The synthesis of ozone by means of dielectric barrier discharge (DBD) is extensively used in industry. Ozone generators available on the market differ in ozone production capacities, electrode arrangements and working parameters, but operate with a uniformly distributed filamentary discharge plasma pattern. In the presented work the benefits of inhomogeneous feed gas processing are explored. Causality between power induction, production efficiency and working parameters are investigated. Different electrode arrangements, evenly distributed within a given space parameter, were designed, simulated, manufactured and tested on a representative scale. A finite element model was utilized to simulate an inhomogeneous power induction pattern along the ozone generator tube. The simulation yielded the local power density, the local gas temperature gradient and the relative DBD packing density. Results show that the degree of filamentation turns out to be decisive, indicating a new potential by means of plasma tailoring. An arrangement with a pronounced power induction at the inlet of the ozone generator revealed several advantages over homogeneous plasma processing arrangements, for which an increase in robustness and a reduction in electrical power consumption are achieved.
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Galstyan, Andriy, Andrii Bushuiev, Kateryna Skorokhod, Anna Krasylnikova, and Marharyta Zhurba. "OXIDATION PRODUCTS OF ETHYLBENZENE AND ITS SUBSTITUTED BY OZONE IN ACETIC ACID." Chemistry, Technology and Application of Substances 3, no. 2 (November 1, 2020): 191–98. http://dx.doi.org/10.23939/ctas2020.02.191.

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Based on the obtained kinetic regularities and the mixture of the products of the reaction of ethylbenzene oxidation with ozone in acetic acid, the scientific bases of the technology of synthesis of acetophenone was developed. It is shown that in the ozonation conditions, in the presence of manganese (II) acetate, it is possible to direct oxidation mainly through the ethyl group of the substrate with the formation of aromatic products. The technological parameters are studied and the optimal conditions for the process realization are ascertained. The obtained experimental and theoretical results allowed us to propose a new low-temperature low-waste method of acetophenone production, which ensures the efficiency of the process due to the mild oxidation conditions (288 K, atmospheric pressure) and the reduction of toxic waste. The technology can be an alternative to existing methods of the synthesis of aromatic ketones.
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Gordeyenya, E. A., and A. A. Matveyev. "Effect of the waveform of voltage pulses on the efficiency of ozone synthesis in corona discharges." Plasma Sources Science and Technology 3, no. 4 (November 1, 1994): 575–83. http://dx.doi.org/10.1088/0963-0252/3/4/015.

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Xie, Jianping, Wei Fan, Hao Cui, Ningning Feng, Guozhen Wang, Hui Wang, Xinxing Liu, Guanzhou Qiu, and Haiyan Wu. "A novel highly dispersed tetra-metal nano heterogeneous ozone catalyst derived from microbial adsorption and in situ pyrolysis." Nanotechnology 32, no. 6 (November 18, 2020): 065701. http://dx.doi.org/10.1088/1361-6528/abb1ed.

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Abstract In recent years, the pyrolysis of microbial biomasses that adsorb various metal ions has enabled the preparation of carbon-based polymetallic nanomaterials with excellent electrocatalytic and electrical energy storage properties. However, the preparation of ozone catalysts by this technique and the corresponding catalytic oxidation mechanism are still unclear. In this study, an Escherichia coli strain (BL21) was used for tetra-metal (Cu, Fe, Mn and Al) absorption and the obtained microbial biomass was pyrolyzed under the protection of a nitrogen flow at 700 °C and activated at 900 °C to prepare a microbial-char-based tetra-metal ozone catalyst (MCOC). This was used to degrade phenol and coking wastewater and exhibited a strong catalytic capability for coking wastewater, whose chemical oxygen demand removal efficiency of 70.86% is 16.7% higher than that of pure ozone and 14.67%, 7.21% and 3.58% higher than that of three commercial catalysts, respectively. It also improved the efficiency of ozonation for phenol by 33%. The MCOC was characterized by x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy–energy-dispersive spectroscopy, transmission electron microscopy and other methods. The results demonstrated that the spherical metal nanoparticles had sizes ranging from 3 nm to 7 nm and that crystals of Fe2O3 and Fe3P were observed. The study showed that the MCOC promoted the production of more hydroxyl radicals and superoxides from ozone, which attack organics. The oxygen vacancies of the catalyst were also investigated. It was proved that the Lewis acid sites on the surface of metal oxides are the active centers of ozone decomposition. Therefore, this work provides a new method for the synthesis of multi-metal nanocomposites and expands the application of biosynthetic nanomaterials.
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Wood, Georgia F., Irina M. Terrero Rodríguez, Joshua J. Tully, Shayantan Chaudhuri, and Julie V. Macpherson. "Electrochemical Ozone Generation Using Compacted High Pressure High Temperature Synthesized Boron Doped Diamond Microparticle Electrodes." Journal of The Electrochemical Society 168, no. 12 (December 1, 2021): 126514. http://dx.doi.org/10.1149/1945-7111/ac3ff4.

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Electrochemical ozone production (EOP) from water is an attractive, green technology for disinfection. Boron doped diamond (BDD) electrodes, grown by chemical vapor deposition (CVD), have been widely adopted for EOP due to their wide anodic window in water and excellent chemical and electrochemical stability. High pressure high temperature (HPHT) synthesis, an alternative growth technique used predominantly for the high-volume synthesis of nitrogen doped diamond microparticles, has been seldom employed for the production of conductive BDD electrodes. In this paper, we demonstrate, for the first time, the use of BDD electrodes fabricated from HPHT conductive BDD microparticles for EOP. The BDD microparticles are first compacted to produce freestanding solid electrodes and then laser micromachined to produce a perforated electrode. The compacted HPHT BDD microparticle electrodes are shown to exhibit high EOP, producing 2.23 ± 0.07 mg L−1 of ozone per ampere of current, at consistent levels for a continuous 20 h period with no drop off in performance. The HPHT electrodes also achieve a reasonable current efficiency of 23%, at a current density of 770 mA cm−2.
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Contreras-Bustos, Roberto, Fabricio Espejel-Ayala, Bibiana Cercado-Quezada, Jaime Jiménez-Becerril, and Melania Jiménez-Reyes. "Adsorption of Zn2+ from solutions on manganese oxide obtained via ozone precipitation reaction." Polish Journal of Chemical Technology 18, no. 1 (March 1, 2016): 46–50. http://dx.doi.org/10.1515/pjct-2016-0008.

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Abstract Synthesis via ozone precipitation reaction was used to obtain manganese dioxide (OMD) and it was probed as an adsorbent for zinc ions. Adsorption was followed along shaking time and increasing ratio [NO3−] / [Zn2+], and isotherms were obtained at different pH values and in the presence of several anions (chloride, nitrate, sulphate, and acetate). It was found that adsorption equilibrium is fast and follows the pseudo-second order model (qe = 34 ±1 mg/g and K = 0.07 ±0.01 g/mg h). Isotherms were fitted to Langmuir, Freundlich, and Langmuir-Freundlich models, and the best fitting was found with the last one. The process is dependent on pH and the efficiency increases from pH 1 to 4. The ratio [NO3−] / [Zn2+] up to 3 does not seem to change the behaviour of the process. Regarding the anions, the efficiency of Zn(II) adsorption occurs according to: acetate > nitrate and sulphate > chloride. Manganese oxide obtained via ozonization is an excellent adsorbent for zinc ions.
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Tundo, Pietro. "Chlorine-free synthesis: An overview." Pure and Applied Chemistry 84, no. 3 (February 24, 2012): 411–23. http://dx.doi.org/10.1351/pac-con-12-02-02.

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Since the Industrial Revolution, chlorine has featured as an iconic molecule in process chemistry even though its production by electrolysis of sodium chloride is very energy-intensive. Owing to its high energy and reactivity, chlorine allows the manufacture of chlorinated derivatives in a very easy way: AlCl3, SnCl4, TiCl4, SiCl4, ZnCl2, PCl3, PCl5, POCl3, COCl2, etc. in turn are pillar intermediates in the production of numerous everyday goods. This kind of chloride chemistry is widely used because the energy is transferred to these intermediates, making further syntheses easy. The environmental and health constraints (toxicity and eco-toxicity, ozone layer depletion) and the growing need for energy (energy efficiency, climate change) force us to take advantage from available knowledge to develop new chemical strategies. Substitution of chlorine in end products in compounds where “chlorine is used in the making” means that we avoid electrolysis as primary energetic source; this makes chemistry “without chlorine” considerably more difficult and illustrates why it has not found favor in the past. The rationale behind this Special Topic issue is to seek useful and industrially relevant examples for alternatives to chlorine in synthesis, so as to facilitate the development of industrially relevant and implementable breakthrough technologies.
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Dissertations / Theses on the topic "Ozone synthesis efficiency"

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Махонін, Микола Віталійович. "Метод визначення параметрів генератору медичного озону для ефективного підвищення його продуктивності." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/42015.

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Дисертація на здобуття наукового ступеня кандидата технічних наук (доктора філософії) за спеціальністю 05.11.17 «Біологічні та медичні прилади і системи». – Національний технічний університет «Харківський політехнічний інститут», Харків, 2019. Дисертація Махоніна М.В. присвячена вирішенню однієї з актуальних науково-технічних задач сучасного медичного приладобудування – підвищенню ефективності генератору медичного озону за рахунок визначення параметрів розрядної камери, напруги живлення та витрати кисню. На даний час у світі активно використовують озон та його суміші для широких потреб різних галузей. Для отримання озону використовуються спеціальні генератори озону різних типів у залежності від сфери їх застосування. Ці генератори відрізняються розмірами, кількістю озону, що генерується за відрозок часу та інші. Особливістю ж генераторів медичного озону є те, що необхідно підтримувати задані параметри отримуваної озоно-кисневої суміші на протязі усього часу проведення процедури, а у якості робочого газу використовується медичний кисень. Це дозволяє реалізовувати методики озонотерапії для максимально ефективного лікування пацієнтів. Типові параметри озоно-кисневої суміші, які повинен забезпечувати медичний генератор озону регламентуються в Україні «Методиками для застосування озону в медичній практиці», які були затверджені Міністерством охорони здоров’я в 2004 році. Згідно сучасної редакції цих методик концентрація озону в озоно-кисневій суміші повинна змінюватись у діапазоні від 0,1 до 80 мг/л, а витрата суміші від 0,1 до 1 л/хв. Медичні генератори озону активно використовуються у кабінетах озонотерапії та медичних установах України, країн СНД, а також країн Латинської Америки. Щорічно у світі проводиться велика кількість конференцій присвячених озонотерапії, на яких вона отримує свій подальший розвиток Практичне використання генераторів медичного озону свідчить, що більшість апаратури, що використовуються, потребує вдосконалення для забезпечення роботи на основі сучасних медичних рішень у лікуванні. Тобто розробка сучасного генератора потребує не тільки відповідність параметрів сучасним вимогам, а й ще запас на розвиток та можливість збільшення значень концентрації озону. Крім того, у більшості медичних генераторів озону спостерігається невідповідність заявлених параметрів озоно-кисневої суміші та значення продуктивності по озону. Продуктивність генератора озону, в свою чергу, залежить від: параметрів розрядної камери, параметрів напруги живлення, параметрів робочого газу. Вирішенням проблему пошуку оптимальних значень цих параметрів для підвищення ефективності роботи генератора озона займаються багато науковців, серед яких можна виділити японських, німецьких та науковців з країн СНД. Але на даний момент ще не існує універсальної моделі розрахунку параметрів генератору Таким чином, задача підвищення ефективності роботи генератора медичного озону за рахунок визначення найкращих параметрів його вузлів, що дозволить підвищити якість процедур озонотерапії є актуальним і перспективним напрямком розвитку генераторів озону. У дисертаційній роботі вперше побудовано математичну модель синтезу озону в розрядній камері генератора медичного озону, яка враховує вплив не тільки параметрів електричної енергії, а також параметрів розрядної камери та робочого газу. Отримані залежності впливу параметрів електричної енергії на синтез озону у розрядній камері на основі проведеного аналізу та з використанням комп’ютерного моделювання. Отримала подальший розвиток модель процесу генерації озону в бар'єрному розряді, яка, на відміну від існуючої, враховує не тільки параметри напруги живлення і розміри камери, але і процеси, що відбуваються в розрядному проміжку. Запропоновано методику розрахунку основних параметрів генератора озону при його розробці, що дозволяє підвищити ефективність синтезу озону. Практичне значення одержаних результатів полягає у обґрунтованні переліку параметрів, що чинять найбільший вплив на продуктивність генератора медичного озону; інженерних розрахунках параметрів генератора медичного озону, які дозволили оптимізувати конструкцію генератора з заданими параметрами; реалізації експериментального зразка генератора медичного озону з вдосконаленою системою автоматичного регулювання витрати газу, що дозволила забезпечити виконання широко спектру процедур озонотерапії. Отриманні практичні результати дисертаційної роботи впроваджені на НВП «Еконіка» при розробці та виготовлення сучасних генераторів медичного озону, а також розроблений макетний зразок пройшов медичну апробації у медичному центрі «Пульс-медика» та у Інституті медичної радіології ім. С.П. Григор’єва.
Thesis for the degree of candidate of technical sciences (PhD) in the specialty 05.11.17 “Biological and medical devices and systems”. -National Technical University "Kharkov Polytechnic Institute", Kharkov, 2019. The thesis is devoted to the solution of one of the current scientific and technical problems of modern medical instrument making - increasing the efficiency of the medical ozone generator by determining the parameters of the discharge chamber, the supply voltage and the oxygen consumption. Currently, ozone and its mixtures are widely used in the world for the wide range of applications. Different types of ozone generators depending on their application are used for ozone synthesis. These generators differ in size, the amount of ozone generated by the time span, etc. The peculiarity of the generators of medical ozone is that it is necessary to maintain the prescribed parameters of the resulting ozone-oxygen mixture throughout the entire duration of the procedure, and medical oxygen is used as the working gas. This allows us to implement ozone therapy techniques for the most effective treatment of patients. Typical parameters of the ozone-oxygen mixture, which the ozone generating plant should provide, are regulated in Ukraine "Methods for the application of ozone in medical practice", which were approved by the Ministry of Health in 2004. According to the modern version of these methods, the concentration of ozone in the ozone-oxygen mixture should vary in the range from 0.1 to 80 mg / l, and the flow rate of the mixture is from 0.1 to 1 l / min. Medical ozone generators are actively used in the offices of ozonotherapy and medical institutions in Ukraine, CIS countries, as well as Latin American countries. A large number of conferences devoted to ozone therapy are being held annually in the world in which it is further developed. The practical use of generators of medical ozone shows that most of the equipment used needs to be improved to provide work on the basis of modern medical solutions in treatment. That is, the development of a modern generator requires not only compliance with the parameters of modern requirements, but also a stock for development and the possibility of increasing the values of ozone concentration. In addition, in most medical ozone generators there is a discrepancy between the stated parameters of the ozone oxygen mixture and the value of ozone productivity. The performance of the ozone generator, in turn, depends on: the parameters of the discharge chamber, the parameters of the supply voltage, the parameters of the working gas. Many scientists, including Japanese, German and scholars from the CIS countries, are engaged in solving the problem of finding the optimal values of these parameters for increasing the efficiency of ozone generator operation. But at the moment there is still no universal model for calculating the parameters of the ozone generator. Thus, the task of increasing the efficiency of the medical ozone generator by determining the best parameters of its nodes, which will improve the quality of ozone therapy procedures, is an urgent and promising direction for the development of ozone generators. In the dissertation, for the first time, a mathematical model of the synthesis of ozone in a digital chamber of the medical ozone generator was constructed, which takes into account the influence not only of the parameters of electric energy, but also of the parameters of the discharge chamber and the working gas. The dependence of the influence of electric energy parameters on the synthesis of ozone in a discharge chamber was obtained on the basis of the conducted analysis and using computer simulation. The model of the ozone generation process in the barrier discharge has been further developed, which, in contrast to the existing one, takes into account not only the power supply parameters and camera dimensions, but also the processes occurring in the discharge gap. The method of calculation of the basic parameters of the ozone generator during its development, which allows increasing the efficiency of ozone synthesis, is proposed. The practical value of the results obtained is to justify the list of parameters that have the greatest impact on the performance of the medical ozone generator; engineering calculations of parameters of the generator of medical ozone, which allowed to optimize the design of the generator with the given parameters; the implementation of an experimental model of the medical ozone generator with an improved system of automatic regulation of gas consumption, which allowed to ensure the implementation of a wide range of procedures for ozone therapy. The practical results of the dissertation work were introduced at the Scientific-Production Enterprise "Econika" in the development and manufacture of modern generators of medical ozone, and also a prototype sample was developed, was tested at the medical center "Pulse Medika" and at the Institute of Medical Radiology N.A. Grigoriev.
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Махонін, Микола Віталійович. "Метод визначення параметрів генератору медичного озону для ефективного підвищення його продуктивності." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/42014.

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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.11.17 – біологічні та медичні прилади і системи. Національний технічний університет «Харківський політехнічний інститут», Харків, 2019 р. Дисертацію присвячено розробці методу визначення параметрів генератору медичного озону для ефективного підвищення його продуктивності за рахунок визначення параметрів його частин з урахуванням впливу факторів різної природи. На основі дослідження питання побудови генераторів медичного озону була доведена актуальність дослідження шляхів підвищення його ефективності. Наведені основні фактори, що впливають на продуктивність генератора озону. Запропонована математична модель на основі використання елементарного об’єму , що описує процеси, які відбуваються у розрядній камері при подачі напруги. Розроблено метод визначення параметрів розрядної камери генератору медичного озону, який дозволяє отримати найбільш ефективну конструкцію при заданих режимах роботи. Проведено дослідження розробленної автоматичної системи витрати робочого газу з поліпшеними характеристиками, яка дозволяє здійснювати основні методики озонотерапії. Доведена працездатність даної системи на основі роботи макета генератора медичного озону при проходженні медичної апробації.
Thesis for the degree of candidate of technical sciences in specialty 05.11.17 – biological and medical devices and systems. – National Technical University "Kharkіv Polytechnic Institute", Kharkіv, 2019. The thesis is devoted to the development of a method for determining the parameters of a medical ozone generator to effectively increase its productivity by determining the parameters of its constituent parts, taking into account the influence of factors of different nature. On the basis of the study of the issues of constructing generators of medical ozone, the relevance of the study of ways to increase its efficiency was proved. A mathematical model based on the use of a single volume, which describes the processes occurring in the discharge chamber when the voltage is applied, is proposed. The level of influence of the parameters of the working gas and the geometry of the discharge chamber on the performance of the ozone generator, as well as on the stability of the parameters of the ozone-oxygen mixture, which were set. A method has been developed for calculating the parameters of a discharge chamber of a medical ozone generator, which makes it possible to obtain the most efficient design for given operating modes. A study has been carried out on the development of an automated working gas consumption system with improved characteristics, which makes it possible to carry out the main methods of ozone therapy. The efficiency of this system has been proved on the basis of the work of a medical ozone generator layout during the passage of medical approbation.
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Book chapters on the topic "Ozone synthesis efficiency"

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Taber, Douglass. "The Kobayashi Synthesis of (-)-Norzoanthamine." In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0105.

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The Zoanthus alkaloids, exemplified by (-)-norzoanthamine 3a and zoanthamine 3b, show promising activity against osteoporosis. Susumu Kobayashi of the Tokyo University of Science assembled (Angew. Chem. Int. Ed. 2009, 48, 1400; Angew. Chem. Int. Ed. 2009, 48, 1404) the challenging tricyclic core of 3a employing the intramolecular Diels-Alder cyclization of 1 to 2. The cyclopentane of 1 served as useful scaffolding, even though it was cleaved en route to 3a. The cyclohexane ring of 1 has five of its six positions substituted, including three that are alkylated quaternary centers. The starting point for the preparation of 1 was the enantiomerically-pure Hajos-Parrish ketone 4, containing the first of the those quaternary centers. Conjugate addition of MeLi established the second quaternary center. The less stable endo alkyl branch of 1 was installed by conjugate addition to the more reactive α-methylene ketone of the cross-conjugated 5, followed by kinetic quench. Addition of vinyl cuprate across the open face of the enone 7 then established the final quaternary center, setting the stage for the intramolecular Diels-Alder reaction. The silyl enol ether from the cyclization of 1 was not stable, so it was directly oxidized to the enone 2. The keto phosphonate 16 for the last two rings of 3a was prepared from the previously-reported crystalline glutamic acid-derived mesylate 12. Reduction and homologation delivered the ester 14, that was condensed with the phosphonate anion 15 to give 16. The congested cyclopentanone 17, derived from 2, was most efficiently deprotonated with n -BuLi. Exposure of the resulting silyl enol ether to ozone led to the α-hydroxylated product 18. Unexpectedly but happily, oxidative cleavage of 18 delivered, after deprotection and reprotection, the more congested aldehyde 19. This cleavage may be proceeding by tautomerization of 18 to the regioisomeric keto alcohol. The aldehyde 19 was condensed with the keto phosphonate 16, to give, after hydrogenation, the keto lactone 20. A series of oxidation state adjustments then completed the synthesis of (-)-norzoanthamine 3a.
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Manke, Charles W., and Esin Gulari. "Rheological Properties of Polymers Modified with Carbon Dioxide." In Green Chemistry Using Liquid and Supercritical Carbon Dioxide. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780195154832.003.0016.

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Use of supercritical fluids (SCFs), particularly supercritical carbon dioxide, as alternative solvents in polymer synthesis and processing is a rapidly growing research area with successful industrial applications (McCoy, 1999). In some cases, the need for alternative solvents is based on environmental concerns, with regulations mandating replacement solvents. An environmentally mandated example is the 1995 ban of the use of chlorofluorocarbons (CFCs) as physical blowing agents in the manufacture of polymeric foams after CFCs were classified as class-I-ozone-depleting substances (ODPs). Among the alternative blowing agents are gases like CO2 and N2 and refrigerants such as 1,1-difluoroethane (R152a) and 1,1,1,2-tetrafluoroethane (R134a). Under the foaming conditions, at temperatures above the glass transition temperature of a polymer, and at pressures required for flow of highly viscous polymer melts, these alternative blowing agents are frequently supercritical. When polymers are formed into final products by various melt-processing techniques, such as extrusion, injection molding, blow molding, foaming, and spin-coating, extremely high melt viscosity presents a major difficulty. A common method to moderate the processing conditions is to add a liquid solvent or plasticizer to the melt. Solvents and plasticizers lower the glass transition temperature, Tg, of the polymer so that the polymer can be made to flow at lower pressures and temperatures. Replacing liquid solvents with SCFs presents unique processing advantages. Higher diffusivity and lower viscosity of SCFs, compared with liquid solvents, increase rates of dissolution and mixing. The properties of polymer–SCF solutions are tunable via pressure or temperature changes, thus allowing efficient downstream separations. Most importantly, dissolution of an SCF produces very large reductions in melt viscosity compared with a liquid solvent dissolved in the melt. Whether the interest in using SCFs in polymer synthesis and processing is driven by environmental concerns or processing advantages, it is important to understand the rheological behavior of polymer–SCF mixtures. In this chapter, we describe rheological measurements of polymer melts containing dissolved gases for two polymers, polydimethylsiloxane (PDMS) swollen with CO2 at 50 °C and 80 °C and polystyrene (PS) swollen with CO2, R152a, and R134a at 150 °C and 175 °C.
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Conference papers on the topic "Ozone synthesis efficiency"

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Xie, Yingbai, Yingfu Liu, Yingcheng Mai, and Luxiang Zong. "The Thermodynamic Analysis and Experimental Investigation on Transcritical Carbon Dioxide Heat Pump System." In ASME 2010 4th International Conference on Energy Sustainability. ASMEDC, 2010. http://dx.doi.org/10.1115/es2010-90391.

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Synthetic refrigerants such as CFCs and HCFCs deplete ozone and cause greenhouse effect. CO2 as a natural working fluid has zero Ozone Depletion Potential and its Global Warming Potential is equal to 1, is receiving more and more attention in the refrigeration field. Because the critical temperature of CO2 is only 31.1°c, the trans-critical cycle can be used to improve the coefficient of performance of the system. The thermodynamic analysis and experimental investigation on trans-critical carbon dioxide heat pump system are carried out in this paper. It points out that there is an optimum operational pressure on trans-critical carbon dioxide heat pump cycle, when the outlet temperature of gas cooler is constant, the coefficient of performance increases with increasing evaporating temperature at the same conditions, and the operational efficiency increased with decrease of gas cooler exit temperature. So in order to obtain the optimum performance, the influence of evaporating temperature, gas cooler exit temperature, and the operational pressure should be considered during the designing and operating transcritical carbon dioxide heat pump system.
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2

Fronk, Brian M., and Srinivas Garimella. "Heat Transfer and Pressure Drop During Condensation of Ammonia in Microchannels." In ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/mnhmt2012-75265.

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An experimental investigation of condensation heat transfer and pressure drop of ammonia flowing through a single, circular, microchannel (D = 1.435 mm) was conducted. The use of ammonia in thermal systems is attractive due to its high latent heat, favorable transport properties, zero ozone depletion (ODP), and zero global warming potential (GWP). At the same time, microchannel condensers are also being adopted to increase heat transfer performance to reduce component size and improve energy efficiency. While there is a growing body of research on condensation of conventional refrigerants (i.e., R134a, R404A, etc.) in microchannels, there are few data on condensation of ammonia at the microscale. Ammonia has significantly different fluid properties than synthetic HFC and HCFC refrigerants. For example, at Tsat = 60°C, ammonia has a surface tension 3.2 times and an enthalpy of vaporization 7.2 times greater than those of R134a. Thus, models validated with data for synthetic refrigerants may not predict condensation of ammonia with sufficient accuracy. The test section consisted of a stainless steel tube-in-tube heat exchanger with ammonia flowing through a microchannel inner tube and cooling water flowing through the annulus in counterflow. A high flow rate of water was maintained to provide an approximately isothermal heat sink and to ensure the condensation thermal resistance dominated the heat transfer process. Data were obtained at mass fluxes of 75 and 150 kg m−2 s−1, multiple saturation temperatures, and in small quality increments (Δx∼15–25%) from 0 to 1. Trends in heat transfer coefficients and pressure drops are discussed and the results are used to assess the applicability of models developed for both macro and microscale geometries for predicting the condensation of ammonia.
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Reports on the topic "Ozone synthesis efficiency"

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Koven, William, Gordon Grau, Benny Ron, and Tetsuya Hirano. Improving fry quality, survival and growth in commercially farmed fish by dietary stimulation of thyroid hormone production in premetamorphosing larvae. United States Department of Agriculture, 2004. http://dx.doi.org/10.32747/2004.7695856.bard.

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There is a direct correlation between successful metamorphosis from larvae to post-larvae and the quality of the resultant juveniles or fry. Juvenile quality, in turn, is a major factor influencing fish production level and market price. However, following the profound morphological and physiological changes occurring during metamorphosis, the emerging juveniles in some species characteristically demonstrate heterotrophic growth, poor pigmentation, cannibalism and generally poor survival. The white grouper (Epinephelus aeneus) in Israel and the Pacific threadfin (Polydactylussexfilis) in Hawaii are two promising candidates for mariculture that have high market value but a natural fishery that has sharply declined in recent years. Unfortunately, their potential for culture is severely hampered by variable metamorphic success limiting their production. The main objective was to compare the efficacy and economic viability of dietary or environmental iodine on metamorphic success and juvenile quality in the white grouper and the pink snapper which would lead to improved commercial rearing protocols and increased production of these species both in Israel and the US. The Hawaii Institute of Marine Biology encountered problems with the availability of pink snapper brood stock and larvae and changed to Pacific threadfin or moi which is rapidly becoming a premier aquaculture species in Hawaii and throughout the Indo-Pacific. The white grouper brood stock at the National Center for Mariculture was lost as a result of a viral outbreak following the sudden breakdown of the ozone purification system. In addition, the NCM suffered a devastating fire in the fall of 2007 that completely destroyed the hatchery and laboratory facilities although the BARD project samples were saved. Nevertheless, by studying alternate species a number of valuable findings and conclusions that can contribute to improved metamorphosis in commercially valuable marine species resulted from this collaborative effort. The Israeli group found that exposing white grouper larvae to external TH levels synchronized and increased the rate of metamorphosis. This suggested that sub-optimal synthesis of TH may be a major factor causing size heterogeneity in the larval population and high mortality through cannibalism by their larger more metamorphosed cohorts. Two protocols were developed to enrich the larvae with higher levels of the TH precursor, iodine; feeding iodine enriched Artemia or increasing the level of seawater iodine the larvae are exposed to. Results of accumulated iodine in gilthead seabream larvae indicated that the absorption of iodine from the water is markedly more efficient than feeding iodine enriched Artemia nauplii. Samples for TH, which will be analyzed shortly, will be able to determine if another dietary factor is lacking to effectively utilize surplus tissue iodine for TH synthesis. Moreover, these samples will also clarify which approach to enriching larvae with iodine, through the live food or exposure to iodine enriched seawater is the most efficient and cost effective. The American group found that moi larvae reared in ocean water, which possessed substantially higher iodine levels than those found in seawater well water, grew significantly larger, and showed increased survival compared with well water reared larvae. Larvae reared in ocean water also progressed more rapidly through developmental stages than those in low-iodine well seawater. In collaboration with Israeli counterparts, a highly specific and precise radioimmunoassay procedure for thyroid hormones and cortisol was developed. Taken altogether, the combined Hawaiian and Israeli collaborative research suggests that for teleost species of commercial value, adequate levels of environmental iodine are more determinate in metamorphosis than iodine levels in the live zooplankton food provided to the larvae. Insuring sufficiently high enough iodine in the ambient seawater offers a much more economical solution to improved metamorphosis than enriching the live food with costly liposomes incorporating iodine rich oils.
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