oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 213 )

2018 ( 257 )

2017 ( 226 )

2016 ( 310 )

Custom range...

Search Results: 1 - 10 of 111829 matches for " Piliss?o "
All listed articles are free for downloading (OA Articles)
Page 1 /111829
Display every page Item
Potential application of native lipases in the resolution of (RS) - phenylethylamine
Pilisso, Cristiane;Carvalho, Patrícia de O.;Nascimento, Maria da G.;
Journal of the Brazilian Chemical Society , 2010, DOI: 10.1590/S0103-50532010000600005
Abstract: the performance of two native lipases (lipase from aspergillus niger and rhizoupus oligosporus) in the resolution of (rs)-phenylethylamine (1), varying the temperature, acyl donor type (ethyl acetate, vinyl acetate, iso-propenyl acetate and acetic anhydride) and organic medium, was studied. the effect of the nature of the anion using native a. niger lipase in n-heptane with a series of imidazolium-based ils [bmim][x], where x = bf4, pf6, scn and cl, was also evaluated. using the lipase from a. niger, the r-2b amide was obtained with conversions from 6 to > 99% and e-values from 2 to > 200, with n-heptane or n-hexane. this lipase showed better e-values in a two-phase system using n-heptane and [bmim][pf6] or [bmim][bf4] 9:1 (v/v), obtaining values of 9 and 7, respectively, when vinyl acetate was used as the acyl donor, compared to the use of pure n-heptane (e = 2). the series for the anions in terms of decreasing performance was as follows: pf6- >bf4- > scn- > cl-.
The influence of conventional heating and microwave irradiation on the resolution of (RS)-sec-butylamine catalyzed by free or immobilized lipases
Pilisso, Cristiane;Carvalho, Patrícia de Oliveira;Nascimento, Maria da Gra?a;
Journal of the Brazilian Chemical Society , 2012, DOI: 10.1590/S0103-50532012005000033
Abstract: the lipases cal-b, psl, psl-c, psl-d, and a. niger lipase, free or immobilized in starch (obtained from two types of yam, known in brazil as “cará” (discorea alata l.) and “inhame” (colocasia esculenta (l.) schott) or gelatin films, were used in the acylation of (rs)-sec-butylamine with different acyl donors in various organic solvents applying conventional heating (ch) or microwave (mw) irradiation. in the case of free a. niger lipase, the conversion degrees were three times higher using mw irradiation when compared to conventional heating at 35 oc. using free a. niger lipase, the (r)-amide was obtained with a conversion degree of 21%, resulting in eep > 99% and e-value (enantioselectivity value) > 200, in 1 min of reaction under mw irradiation. when the a. niger lipase was immobilized in yam starch films, the (r)-amide was obtained in moderate conversions of 8-25% after 3 or 5 min of reaction under mw irradiation, but with higher selectivity (eep > 99% and e > 200) in comparison with the free form (conversion degree of 45%, eep 81% and e value of 18).
Stress Loops Effect in Ductile Failure of Mild Steel  [PDF]
O.O. Oluwole
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2009, DOI: 10.4236/jmmce.2009.84026
Abstract: A simulation study of effect of stress on mild steel microstructure has revealed stress loops at areas of stress application which are believed to be the root cause of the ductile failure morphology (cup and cone) in ductile alloys under plane strain conditions. The areas of concentration of these stress loops were observed to be that of subsequent instability (or necking) observed in mild steel and other materials of low friction (flow) stress. Shear stress loops with angular bearing of 450 to the tensile axis were observed to instigate both the failure site and shear morphology in these materials. In plane stress conditions, shear was seen to be that of a wave shape running obliquely to area of stress application resulting in oblique necking observed in thin mild steel sheets.
Boundary Value Problem for an Operator-Differential Riccati Equation in the Hilbert Space on the Interval  [PDF]
O. O. Pokutnyi
Advances in Pure Mathematics (APM) , 2015, DOI: 10.4236/apm.2015.514081
Abstract: The paper is devoted to obtaining the necessary and sufficient conditions of the solvability of weakly perturbed boundary-value problems for the nonlinear operator-differential Riccati equation in the Hilbert space on the interval and whole line with parameter ?. We find the solution of the given boundary value problem which for ε = 0 turns in one of the solutions of generating boundary value problem. Solution of the generating problem is constructed with the using generalized operator in analytical form. Iterative process for finding of solutions of weakly nonlinear equation with quadratic error is constructed.
Vertex-transitive maps on a torus
O. Such
ACTA MATHEMATICA UNIVERSITATIS COMENIANAE , 2011,
Abstract: We examine FVT (free, vertex transitive) actions of wallpaper groups on semiregular tilings. By taking quotients by lattices we then obtain various families of FVT maps on a torus, and describe the presentations of groups acting on the torus. Altogether there are 29 families, 5 arising from the orientation preserving wallpaper groups and 2 from each of the remaining wallpaper groups. We prove that all vertex-transitive maps on torus admit an FVT map structure.
Vertex-transitive maps on a torus
O. Such
ACTA MATHEMATICA UNIVERSITATIS COMENIANAE , 2011,
Abstract: We examine FVT (free, vertex transitive) actions of wallpaper groups on semiregular tilings. By taking quotients by lattices we then obtain various families of FVT maps on a torus, and describe the presentations of groups acting on the torus. Altogether there are 29 families, 5 arising from the orientation preserving wallpaper groups and 2 from each of the remaining wallpaper groups. We prove that all vertex-transitive maps on torus admit an FVT map structure.
Definition of secret reasons of errors, appeared during aviation operators’ professional activity Определение скрытых причин происхождения ошибок, возникающих в профессиональной деятельности авиационных операторов ВИЗНАЧЕННЯ ПРИХОВАНИХ ПРИЧИН ПОХОДЖЕННЯ ПОМИЛОК, ЩО ВИНИКАЮТЬ У ПРОФЕС ЙН Й Д ЯЛЬНОСТ
O.?. Луппо,О.М. Ал?кс??в
Proceedings of National Aviation University , 2005,
Abstract: Development of discover secret reasons of error actions of aviation operators allows to define reasons of secret factors of error action in time and will give opportunity to develop more effective prevention measures in order to prevent mistake actions in time. Разработана система выявления скрытых причин ошибочных действий авиационных операторов, позволяющая своевременно определять причины и механизмы возникновения скрытых факторов, которые приводят к ошибочным действиям, и осуществлять более действенные профилактические мероприятия по их своевременному предотвращению. Розроблено систему виявлення прихованих причин помилкових д й ав ац йних оператор в, що дозволя сво часно визначати причини механ зми виникнення прихованих чинник в, як призводять до помилкових д й, та зд йснювати б льш д в проф лактичн заходи щодо х сво часного запоб гання.
НТЕГРАЦ Я ЗАСОБ В Д АГНОСТИКИ, ПРОГНОЗУВАННЯ КЕРУВАННЯ Р ВНЕМ БЕЗПЕКИ ПОЛЬОТ В Integration of diagnosis, prognosis and management level of safety Интеграция средств диагностики, прогнозирования и управления уровнем безопасности полетов
В.П. Харченко,O.?. Луппо,О.М. Ал?кс??в
Proceedings of National Aviation University , 2007,
Abstract: Розглянуто один з шлях в п двищення контролю за р внем безпеки польот в нтеграц я вс х засоб в форм у комплексних автоматизованих системах. Запропоновано виб р кращого вар анта засобу керування р внем безпеки польот в за допомогою комплексного автоматизованого застосування математичних моделей, методолог чних п дход в до виконання початкових етап в моделювання, концептуального проектування, формал зац алгоритм зац моделей. One of ways rise and control after a level of safety flights is integration of all facilities and forms in the complex automated systems. Acceptance of decision about the choice of the best forms management of mean safety flights level in such terms is erected to satisfaction a number of indexes, and in spite of their possible contradiction is a problem which it is possible to decide by means the complex automated use application of mathematical models, methodological approaches to implementation initial stages of design, conceptual design, formalization and algoritmizationi of models and bases management mean of safety flights level. Рассмотрен один из путей повышения и контроля за уровнем безопасности полетов - интеграция всех средств и форм в комплексных автоматизированных системах. Предлагается выбор лучшего варианта средства управления уровнем безопасности полетов с помощью комплексного автоматизированного применения математических моделей, методологических логических подходов к выполнению начальных этапов моделирования, концептуального проектирования, формализации и алгоритмизации моделей.
НОВ П ДХОДИ ДО КЛАСИФ КАЦ ПРИЧИН АВ АЦ ЙНИХ ПОД Й ТА НЦИДЕНТ В ЯК ЕФЕКТИВНИЙ ЗАС Б П ДВИЩЕННЯ БЕЗПЕКИ ПОЛЬОТ В New approaches to the classification of causes of aviation accidents and incidents as an effective means of improving safety Новые подходы к классификации причин авиационных происшестви
O.?. Луппо,О.М. Ал?кс??в
Proceedings of National Aviation University , 2007,
Abstract: Розглянуто класиф кац ю ав ац йних под й та нцидент в, що да змогу оц нити питому частку кожно структури в зниженн безпеки польот . Виявлено головн причини та частоту повторюваност ав ац йних под й та нцидент в. Оц нено ефективн сть ран ше розроблених проф лактичних заход в щодо попередження однотипних ав ац йних под й та нцидент в у майбутньому. Classification of accidents and incidents makes principle of hieratic collateral subordination, which determines separate classification of direct and main reasons that enables to estimate weight destiny of every structure in the decline of safety flight and expose most bottleneck in the aviation system. Exposure of main reasons and frequency of their repetition, for a concrete period, allows to define the role of each components in the decline of safety of flights and estimate efficiency of the before developed prophylactic measures from warning of the same type aviation events and incidents in a future. Рассмотрены классификация авиационных происшествий и инцидентов, что позволяет оценить удельную долю каждой структуры в снижении безопасности полете. Выявлены основные причины и частоту повторяемости авиационных происшествий и инцидентов. Оценена эффективность ранее разработанных профилактических мероприятий по предупреждению однотипных авиационных происшествий и инцидентов в будущем.
THE PLACE AND THE ROLE OF THE INFORMATION AND COMMUNICATION TECHNOLOGIES IN THE SYSTEM OF EDUCATION IN EUROPEAN UNION COUNTRIES М СЦЕ ТА РОЛЬ НФОРМАЦ ЙНИХ ТА КОМУН КАЦ ЙНИХ ТЕХНОЛОГ Й В СИСТЕМ ОСВ ТИ КРА Н ВРОПЕЙСЬКОГО СОЮЗУ
О.В. Oвчарук
Information Technologies and Learning Tools , 2010,
Abstract: The article deals with the analysis of the problems of ICT application in education sphere in European Union. Particularly the article is about the pupils and teachers access to electronic means and Internet, as well as about ICT place in the school curricula. Стаття присвячена анал зу проблем нформатизац осв ти в кра нах вропейського Союзу, зокрема, доступу учн в та педагог в до електронних засоб в навчання, мереж нтернет. Подано нформац ю щодо м сця КТ в зм ст осв ти загальноосв тн х навчальних заклад в.
Page 1 /111829
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.