309 research outputs found

    Explicit upper bound for the function of sum of divisors

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    we developed the result proved by A.Eviwhere he proved the following  theore

    Operational Images and Relations of Two and Three Variables Hypergeometric Series

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    Based upon the classical derivative and integral operators we introduce a new symbolic operational images for hypergeometric functions of two and three  variables. By means of these symbolic operational images a number of operational relations among the hypergeometric functions of two and three  variables are then found. Other closely-related results are also considered

    Association of Resistin, Visfatin, and Osteoprotegerin in Diabetes Mellitus

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    The aims of the study to evaluate the association between diabetes mellitus and resistin, visfatin and osteoprotegerin levels and studying the interaction of  resistin, visfatin and osteoprotegerin with duration of diabetes mellitus. This is a case/control study conducted on a total 88 subjects; sixty eight patients (25 male and 43 female) compared to twenty healthy persons (7 males and 13 females). Venous blood collected from the patients attending to Diabetic Center in Merjan Teaching Hospital / Babylon/ Iraq. Serum was prepared from collected blood, and used to investigate resistin, vistatin and osteoprotegerin. The present study findings revealed a significant decrease in resistin, visfatin and osteoprotegerin levels when compared with controls. On other the hand, the study showed  that the visfatin and osteoprotegerin increased in 11-15 years of duration of diagnosis, while there was no relation between resistin and duration of diagnosis. Keywords: Diabetes Mellitus, resistin, visfatin and osteoprotegerin

    Étude du rapport entre la géométrie des fils et la rugosité des tissus

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    La suavidad de los tejidos es difícilmente cuantificable puesto que está asociada a una serie de sensaciones subjetivas. Se ha intentado evaluar objetivamente mediante diversos métodos. Uno de los parámetros cuantificables más importantes, que diversos autores relacionan con el tacto de los tejidos es su aspereza o rugosidad superficial. En este trabajo se estudia la relación entre la rugosidad superficial de una serie de tejidos y la deformación filar de los hilados que los constituyen; la deformación filar depende de la geometría de los hilados y esta, a su vez está condicionada por diversas variables. En el trabajo se establecen las relaciones entre la deformación filar y la composición, título y torsión de los hilados de PES/CV, en un intento de poder establecer como influyen estas variables en la rugosidad de los tejidos.The smoothness of the fabrics is hardly quantifies since is associated to a series of subjective sensations. It has been tried to evaluate objectively by means of diverse methods. One of the more important measurable parameters that diverse authors relate to the smoothless of a fabric is its superficial roughness. The present work studies the relationship between the superficial roughness of a series of fabrics and the deformation of the yarns that constitute them. The yarn deformation depends on the geometry of the yarn and this is, as well, depending of diverse variables. In the work the relationships between the yarn deformation and the account and torsion of yarns of different PES/CV compositions are also studied in an attempt of how these variables influence the superficial roughness of the fabrics.La douceur des tissus est difficilement quantifiable car elle est associée à une série de sensations subjectives. Elle a fait l'objet d'une tentative d'évaluation objective à l'aide de plusieurs méthodes. L'un des paramètres quantifiables les plus importants, que divers auteurs associent au tact des tissus, est leur âpreté ou rugosité superficielle. Cette étude porte sur le rappot entre la rugosité superficielle d'un série de tissus et la déformation filaire des filés qui les constituent; la déformation filaie dépend de la géométrie des filés et celle-ci est, à son tour, conditionnée par plusieurs variables. Des rapports son établis entre la déformation filaire et la composition, le titre et la torsion des filés de PES/CV, pour tenter d'établir comment ces variables jouent sur la rugosité des tissus

    Chitosan/Polyacrylamide Green Gels for Water Control in High-Temperature Reservoirs

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    The rheology of a gel system composed of polyacrylamide (PAM) and chitosan is studied under typical reservoir conditions. The impacts of the degree of chitosan deacetylation, temperature, and salinity on the gelation behavior are assessed. The said system was prepared under ambient conditions and matured for 24 h at altered temperatures ranging from 50 up to 125 °C. An optimum formulation has been identified considering the rheological response and the initial viscosity constraints. The increase in the degree of syneresis with the degree of deacetylation indicates the long-Term thermal stability of the gels. Ammonium chloride was an effective retarder for the PAM/chitosan gelant, which delayed the gelation time from 60 to 210 min when 2 wt % is used; however, it compromised the final gel strength. The chitosan/PAM system showed a good rheological behavior and potential as a green plugging agent in high-Temperature oil and gas wells. Chitosan could be an alternative for commercial crosslinkers, such as polyethyleneimine

    Development Of Eco-friendly Chitosan-g-polyacrylamide Preformed Particle Gel For Conformance Control In High-temperature And High-salinity Reservoirs

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    Oil and gas extraction has become challenging nowadays due to the accompanying amount of excess produced water that results in poor recoverability of hydrocarbon, besides other environmental and economic isues. A recent and efficient technology for conformance control is the injection of preformed particle gels (PPGs), which results in a more practical production process. Nevertheless, existing treatments fail in high-temperature reservoirs, are extremely sensitive to salinity, and are hazardous. The characteristics of the designed PPG, such as mechanical strength and thermal durability, is mainly depend on their crosslinking method. Polysaccharides-based gels prepared by physical crosslinking are weaker than the ones crosslinked by strong covalent bonding. This paper uses one of the polysaccharides and proposes an environmentally friendly PPG for water shutoff applications in reservoirs of high temperature (≤130 °C) and high salinity (200,000 ppm), named chitosan grafted polyacrylamide crosslinked with N, N′-methylene bisacrylamide, synthesized chemically by microwave assisted method. The PPG\u27s chemical compositions, grafting and crosslinking mechanism have been investigated by FTIR spectroscopy and SEM techniques. Swelling kinetics, swelling capacity, and mechanical strength measurements were conducted in different conditions to evaluate the influence of the reservoir conditions, such as salinity, temperature, and pH, on the PPG stability. TGA experiments were also performed to examine the thermal stability. Results have shown that the grafting method has produced a PPG with improved mechanical strength, thermal durability, and salt insensitivity. These results are consistent with the testing observations, where the swelling capacities and the storage modulusof Cs/PAMBA samples, with different MBA content, in deionized water were 2.72–11.64 g/g and 4272.1–22,687 Pa, respectively, while they are 2.52–13.82 g/g and 3699.6–22,910, respectively, in saline solution of TDS 67.2976 g/L. The PPGs are thermally stable and resist temperatures up to 130 °C. Besides being eco-friendly, the Cs/PAMBA showed good long-term thermal stability in high-temperature and high-salinity environments

    Impact Of Composition And Salinity On Swelling And Gel Strength Of Poly (acrylamide-co-acrylic Acid) Preformed Particle Gel

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    The effects of various material compositions and reservoir environments on the ultimate strength and swelling kinetics of a commercial preformed particle gel (PPG) have been investigated. This study used different ratios of acrylamide and acrylic acid copolymers with a specific crosslinker concentration. Results have indicated that increasing the acrylic acid proportion enhances the PPGs\u27 ability to swell but weakens their network structure. In contrast, increasing the crosslinker content decreases the swelling ratio and increases the gel strength. The highest equilibrium swelling capacity among the six preformed particle gel samples was obtained for PPG2, which has the highest acrylic acid amount and the lowest crosslinker content, with a swelling ratio of 2400 g/g in deionized water and 59.8 g/g in brine 1 (67535.8 mg/l). On the contrary, PPG5, with the lowest acrylic acid and highest crosslinker content, has a swelling capacity of 239 g/g and more than 17 g/g in distilled and brine 1, respectively. Yet, PPG5 has the highest swollen gel strength of 615.5 Pa in deionized water and 3344 Pa in brine 1. The PPGs\u27 swelling ratios showed stepwise improvements along with increasing temperature, notably after 50 °C, yet the storage modulus (G′) was negatively affected. The PPGs revealed the highest swelling behavior in pH 6–8, decreasing dramatically in more acidic and basic conditions. The swelling ratios of the PPGs in brine 1 at 50 °C were between 12 and 32 g/g, having strengths in the range of 566–5508 Pa, depending on the crosslinker ratio. The PPGs also demonstrated the ability to compete with other commercial PPGs as they have shown physical and thermal stability when aging at 50 °C, specifically those with high crosslinker content (PPG5)

    PREVALENCE OF CONSANGUINEOUS MARRIAGES IN SOUTH SINAI, EGYPT

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    A total of 3961 married couples from six major geographical areas representing the South Sinai governorates in Egypt were studied to assess the rate of consanguineous marriage. The population of six selected areas (St Catherines, Nuweiba, Abu Rudeis, Ras Sudr, El Tor and Abu Zenima) were subdivided into Bedouin, urban and mixed populations. A questionnaire-based interview was conducted showing that the consanguinity rate in this region is 37.5%, with the highest rate recorded in Abu Rudeis (52.3%) and lowest rate in Nuweiba (24.1%). Consanguinity was significantly higher among the Bedouin population compared with the urban population in Abu Rudeis, Ras Sudr, El Tor and Abu Zenima, while in St Catherines and Nuweiba there was no statistically significant difference. Among consanguineous couples, 5%, 60% and 35% were double first cousins, first cousins and second cousins respectively. The mean inbreeding coefficient α of the studied population was 0.0184

    User friendly system for the visually impaired in learning Al-Quran

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    This study presents a method to enable the visually impaired Muslim to learn and read the Al-Quran using Braille Display with software help. The system reads the database which contains all verses of Al-Quran and user will need to select the verse and ayah to read. Besides that, this system can be used in a class to teach visually impaired students to learn Al-Quran. Every word or character typed by the instructor in the main Braille Panel will be transmitted to the sub Braille Panel that is connected to the main Braille Panel. The selected verse of Al-Quran and ayah will also generate an index before being transmitted to the Braille Panel. The index will be transmitted to the Braille Display for people to touch and read the display. A user friendly Graphical User Interface (GUI) will be used to fulfill the ergonomics for the visually impaired user's physical capabilities. Several approaches are used to design and implement the interface for the visually impaired like speech or sound output and Braille display. The Braille codes can be displayed using the Braille panel. The design interface and structure of the system for the visually impaired users in learning Al-Quran is presented

    Expermential Study of the Performance of Fluorescence Collector

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    The luminescent concentrator which used consisting of organic fluorescence dyes such as Rhodamine 6G doped in article Polyvinyl alcohol (PVA) to configure a specific membrane thickness, and then put these films on the glass plate solar collector model with energy halogen Lamp (1000 Watt) as a source of light to represent of fluorescence collector. Examining the effect of these pigments on the efficiency of the solar collector as a function of the temperature difference between the water inside and outside of the solar collector. Where the increasing in the amount of the difference between the temperature refers to increasing the efficiency of the performance of solar collector. Results showed that the efficient performance of the solar collector increases with the increase in the intensity of incident light with existence the luminescent concentrator ,where the rising water temperature of (24 K) compared with (20 K) when there is not existence the luminescent concentrator when the intensity of radiation falling (1500 W/m2) and increasing efficiency of solar collector to 20%
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