1,927 research outputs found
Parallel Processing For Schema Evolution in Database Systems
A thesis submitted to the University of London in partial fulfillment of the requirements of the degree of Doctor of Philosoph
Towards the characterization of a novel thermohalophilic antioxidant Thioredoxin from the metagenome of the Red Sea; LCL of Atlantis II Brine pool
Due to the crucial antioxidant role of Thioredoxin (Trx) system in various vital cellular processes; DNA synthesis, oxidative stress defense, protein folding, apoptosis and cell growth, this fundamental system is widely expressed in mostly all life\u27s kingdoms. Thus using metagenomic approaches to characterize novel Trx system in unexplored harsh environment will open the window for understanding the evolution of Trx system and its unique adaptation in extreme habitations. One of the unexplored unique ecosystems is the Red Sea\u27s Atalntis II brine pool, specifically, the lower convective layer (LCL). The exceptional harsh conditions of the LCL; anoxic condition, high temperature around 70°C, high salinity (26%), and high metal content, have a significant contribution for being a unique infrequent ecosystem. The objective of this study is to characterize a novel Trx isolated from the LCL. Successfully, in the experimental part, Trx was expressed in E. coli and purified, where the purified Trx has shown a clear antioxidant activity with a unique thermohalophilicity. In conclusion, we have characterized a unique antioxidant Trx protein
WIRELESS OFFSHORE PLATFORM STRUCTURAL HEALTH MONITORING
Oil platforms are known for their operation in dangerous environments. The most recent technology adapted is the unmanned platform which is a remotely operated platform without any workers on the platform during the operation to lessen the losses occurs in the platforms. To ensure the safety and the reliability of the new platforms a safety monitoring system is required to be developed. In this report, a new structural health and safety monitoring system for unmanned platforms is proposed and developed. The objectives of the project are to develop a system which processes electrical signals to represent structural parameters, develop the proper communication between different parts of the system and test the feasibility of the system. The new system integrates microprocessor technologies and communication technologies to meet the objectives of the proposed system. The project focused on testing the proper connection between the microprocessor and the measuring devices, and studying and simulating the wireless and underwater communication. The system was tested using strain gages to measure strain and half-cell to measure corrosion. The readings obtained were validated against commercial acquisition systems. The results show the efficiency of the system in different applications to measure different structural parameters. The underwater transmission was simulated using OMNET++. The simulation results show low efficiency of acoustic communication which requires further study and investigation
Experimental research into the effect of some operation factors and rock properties on the rate of penetration
Purpose. The purpose of this research is to investigate the effect of weight on bit (WOB), rotary speed (RPM), and some rock properties on the rate of penetration (ROP).
Methods. Four types of rock were collected from different sites in the south of Egypt (Aswan sandstone, Isawya limestone, Assiut limestone, and Minya marble). These tested samples were drilled by diamond core bit using a fixed laboratory diamond drilling machine under conditions (400 and 1200 rpm), and loads from 12 to 220 kg. WOB, ROP, torque (T) and specific energy (SE) were continuously observed during the drilling trials. The effect of these factors on ROP were examined. Water is used as a flushing and cooling medium.
Findings. The effect of some operation factors on the penetration rate regarding mineral composition and different rock type was evaluated and the general equation was carried out to predict the suitable operation factor which gives the best penetration Rate.
Originality. The effect of some operation factors on the penetration rate regarding mineral composition and different rock type was evaluated and the general equation was carried out to predict the suitable operation factor which gives the best penetration Rate.
Practical implications. The Results demonstrated that ROP was inversely proportional to compressive strength (CS), tensile strength (TS), and density. It was also found that Aswan sandstone, Isawya limestone, Assiut limestone, and Minya marble have CS 111.94 MPa, 131.22 MPa, 125.0 MPa, and 502.5 MPa respectively. Was established that ROP was directly proportional to porosity. Increasing ROP in case of Aswan sandstone is associated with increase in porosity – 23.158%, and in case of Assiut limestone and Isawya limestone ROP is also associated with an increase in porosity – 19.9% and 17.93% respectively. Decreasing ROP in case of Minya marble is associated with decrease in porosity – 2.314%. So, we concluded that marble has lower ROP due to its higher CS, TS, and density and lower porosity than other tested rocks.Мета. Вивчення впливу комплексу основних експлуатаційних параметрів і ряду фізико-механічних властивостей порід на швидкість буріння в умовах різних родовищ Південного Єгипту.
Методика. Були відібрані 4 типи порід з різних районів на півдні Єгипту (Асуанської піщаник, вапняк Ісав, Ассіутскій вапняк і мармур Міньї). Експериментальні зразки отримано на стаціонарній лабораторній буровій установці з алмазним долотом при швидкостях обертання 400 і 1200 об/хв та при навантаженнях від 12 до 220 кг. Під час експериментів постійно вимірювалися навантаження на долото, частота обертання, крутний момент на долоті й питома енергія, а також досліджувався вплив цих факторів на швидкість буріння. Як розчин для промивання і охолоджуючий агент використовувалася вода.
Результати. Встановлено залежності швидкості буріння від навантаження на долото, питомої енергії та частоти обертання і питомої енергії. Виявлено, що для всіх чотирьох типів породи швидкість буріння збільшується з ростом навантаження на долото, в той час як питома енергія зменшується з ростом швидкості буріння. Розроблено ефективний спосіб прогнозування продуктивності бурової установки. Встановлено, що швидкість буріння обернено пропорційна міцності на стиск, міцності на розтягнення й щільності, а також змінюється прямо пропорційно пористості. Визначено, що менша швидкість буріння мармуру пов’язана з великими значеннями міцності на стиск, розтяг і щільність, а також з меншою пористістю у порівнянні з іншими досліджуваними породами.
Наукова новизна. Встановлено нові закономірності взаємозв’язку експлуатаційних параметрів буріння з урахуванням різного типу породи (пісковик, вапняк, мармур) та її мінерального складу, а також обґрунтовано головну умову експлуатаційного фактору, який забезпечує оптимальну швидкість буріння.
Практична значимість. Отримані результати дозволяють вибирати оптимальні параметри і режими буріння в процесі розвідки умов залягання родовищ Південного Єгипту, їх мінерального вмісту та стратиграфічних особливостей. Результати будуть корисними для проектних організацій, наукових інститутів з геології й розвідки, а також гірничих підприємств.Цель. Изучение влияния комплекса основных эксплуатационных параметров и ряда физико-механических свойств пород на скорость бурения в условиях пород различных месторождений Южного Египта.
Методика. Были отобраны 4 типа пород из различных районов на юге Египта (Асуанский песчаник, известняк Исавии, Ассиутский известняк и мрамор Миньи). Экспериментальные образцы получены на стационарной лабораторной буровой установке с алмазным долотом при скоростях вращения 400 и 1200 об/мин и при нагрузках от 12 до 220 кг. Во время экспериментов постоянно измерялись нагрузки на долото, частота вращения, крутящий момент на долоте и удельная энергия, а также и исследовалось влияние этих факторов на скорость бурения. В качестве промывочного раствора и охлаждающего агента использовалась вода.
Результаты. Установлены зависимости скорости бурения от нагрузки на долото, удельной энергии и частоты вращения и удельной энергии. Выявлено, что для всех четырех типов породы скорость бурения увеличивается с ростом нагрузки на долото, в то время как удельная энергия уменьшается с ростом скорости бурения. Разработан эффективный способ прогнозирования производительности буровой установки. Установлено, что скорость бурения обратно пропорциональна прочности на сжатие, прочности на растяжение и плотности, а также изменяется прямо пропорционально пористости. Определено, что меньшая скорости бурения мрамора связана с большими значениями прочности на сжатие, растяжение и плотности, а также с меньшей пористостью по сравнению с другими исследуемыми породами.
Научная новизна. Получены новые закономерности взаимосвязи эксплуатационных параметров бурения с учетом различного типа породы (песчаник, известняк, мрамор) и ее минерального состава, а также обосновано главное условие эксплуатационного фактора, который обеспечивает оптимальную скорость бурения.
Практическая значимость. Полученные результаты позволяют выбирать оптимальные параметры и режимы бурения в процессе разведки условий залегания месторождений Южного Египта, их минерального содержание и стратиграфических особенностей. Результаты будут полезными для проектных организаций, научных институтов по геологии и разведке, а также горных предприятий.Our sincere gratitude for Mining and Metallurgical Engineering Dept. Faculty of Engineering, Assiut, Egypt for invaluable assistance to upgrade and guidance to completed this article
The abject dream of neo-capital: Capitalist urbanism, architecture and endangered liveability of the Middle East’s modern cities
This article interrogates the notion of “New Capital” in the context of the hegemony of neoliberal urbanism in
the Arab cities in the Middle East from historical, socio-economic and spatial perspectives. It reviews the
historical narratives of new centres and districts in Cairo, Beirut and evolving capitalist urbanism and
architecture in the Arabian Peninsula in search of elitist dream of neo-liberal urbanism. It offers a
comprehensive analysis to the notions of neoLiberal ideology and urban policies, neoCapital city as catalyst for
nation-building and neoCapitalist architecture as reproduction of clone structures of western models. The
paper focuses its critical analysis on the aspects of liveability in the contemporary Arab City and its socio-spatial
structures and everyday urban reality. It reports on urban narratives based on archival records, urban projects
and investigation of governmental accounts to determine aspects of success and failure in projects of new
capital cities and districts. It argues that cities are essentially social-spatial system in which hierarchy is a
fundamental element, the lack of which determines abject failure of their anticipated vision
The modern ordinary: Changing culture of living in Egypt’s traditional quarters at the turn of the twentieth Century
Having experienced social and political structures of the nineteenth century Europe, western-educated Egyptian elite used public institutions to force new legislative structures and procedures that ruled out traditional housing forms and spatial systems. This essay detects direct and indirect impact of these changes that informed the spatial change of modern living in Egypt in the first quarter of the twentieth century. It offers analysis of socio-spatial practices and change in ordinary Cairenes’ modes of everyday living, using social routine and interaction to explain spatial systems and changing house forms during the first quarter of the twentieth century. In doing so, the essay utilized archival documents, accounts, formal decrees and novels of the time as well as conducting survey of house forms and spatial organizations in Old Cairo
Experimental and Numerical Investigation of Emulative Connections in Precast Concrete Walls
Grouted connections are widely used in the precast concrete construction. For instance, in precast concrete walls, they are used to connect assemblies of vertically stacked panels. The connection is comprised of a grout cylinder bound by a corrugated metallic duct, which is used to house a large diameter reinforcing bar bridging the horizontal gap of stacked panels. The connection is used to provide vertical continuity to the assembly, and to help resist tensile demands from in-plane bending. Current design guidelines consider such connections through a bar-in-concrete treatment, disregarding its composite nature and the confinement effect of the duct. This has resulted in excessively long connections that could induce planes of reduced stiffness in precast wall panels.
In this thesis, a research program was tailored to investigate the disparity between the real behaviour of grouted connections and their current design code idealization to offer alternative more realistic design provisions. The experimental program was divided into three phases. First, an exploratory study of the bond behaviour of grouted connections under monotonic loads was conducted. Second, the behaviour of grouted connections was compared to bar-in-concrete specimens under monotonic loading. Third, the cyclic behaviour of the connections at various embedment lengths was examined under quasi-static loading. Knowledge gained in the experimental program was used in analytical treatments to develop a novel model that can accurately depict the behaviour of these connections.
Results from the various experimental phases reveal that the bond failures developed in grouted connections are not characterized by brittle tensile splitting modes, irrespective of the level of bond stress along the assembly at different embedded lengths. It was observed that the presence of the corrugated duct offers a continuous restraining field against radial expansion of the grout, causing the bars to be mobilized in much shorter anchored lengths than those suggested by current standards. A numerical model was developed to reproduce the behavior of grouted connections with reasonable accuracy. Its accuracy and computational efficiency should allow modelling full-scale precast wall assemblies.
In this thesis, a research program was tailored to investigate the disparity between the real behaviour of grouted connections and their current design code idealization to offer alternative more realistic design provisions. The experimental program was divided into three phases. First, an exploratory study of the bond behaviour of grouted connections under monotonic loads was conducted. Second, the behaviour of grouted connections was compared to bar-in-concrete specimens under monotonic loading. Third, the cyclic behaviour of the connections at various embedment lengths was examined under quasi-static loading. Knowledge gained in the experimental program was used in analytical treatments to develop a novel model that can accurately depict the behaviour of these connections.
Results from the various experimental phases reveal that the bond failures developed in grouted connections are not characterized by brittle tensile splitting modes, irrespective of the level of bond stress along the assembly at different embedded lengths. It was observed that the presence of the corrugated duct offers a continuous restraining field against radial expansion of the grout, causing the bars to be mobilized in much shorter anchored lengths than those suggested by current standards. A numerical model was developed to reproduce the behaviour of grouted connections with reasonable accuracy. Its accuracy and computational efficiency should allow modelling full-scale precast wall assemblies
Lightweight Mutual Authentication Protocol for Low Cost RFID Tags
Radio Frequency Identification (RFID) technology one of the most promising
technologies in the field of ubiquitous computing. Indeed, RFID technology may
well replace barcode technology. Although it offers many advantages over other
identification systems, there are also associated security risks that are not
easy to be addressed. When designing a real lightweight authentication protocol
for low cost RFID tags, a number of challenges arise due to the extremely
limited computational, storage and communication abilities of Low-cost RFID
tags. This paper proposes a real mutual authentication protocol for low cost
RFID tags. The proposed protocol prevents passive attacks as active attacks are
discounted when designing a protocol to meet the requirements of low cost RFID
tags. However the implementation of the protocol meets the limited abilities of
low cost RFID tags.Comment: 11 Pages, IJNS
Studying the Dynamical Properties of 20 Nearby Galaxy Clusters
Using SDSS-DR7, we construct a sample of 42382 galaxies with redshifts in the
region of 20 galaxy clusters. Using two successive iterative methods, the
adaptive kernel method and the spherical infall model, we obtained 3396
galaxies as members belonging to the studied sample. The 2D projected map for
the distribution of the clusters members is introduced using the 2D adaptive
kernel method to get the clusters centers. The cumulative surface number
density profile for each cluster is fitted well with the generalized King
model. The core radii of the clusters' sample are found to vary from 0.18 Mpc
\mbox{h}^{-1} (A1459) to 0.47 Mpc \mbox{h}^{-1} (A2670) with mean value of
0.295 Mpc \mbox{h}^{-1}.
The infall velocity profile is determined using two different models, Yahil
approximation and Praton model. Yahil approximation is matched with the
distribution of galaxies only in the outskirts (infall regions) of many
clusters of the sample, while it is not matched with the distribution within
the inner core of the clusters. Both Yahil approximation and Praton model are
matched together in the infall region for about 9 clusters in the sample but
they are completely unmatched for the clusters characterized by high central
density. For these cluster, Yahil approximation is not matched with the
distribution of galaxies, while Praton model can describe well the infall
pattern of such clusters.Comment: 16 pages, 8 figure
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