• Proceedings of the Membrane Society of Korea Conference
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• 2002.07a
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• pp.1-12
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• 2002

Desalination by reverse osmosis (RO), which first entered commercial use in the 1970s, was initially mainly used for treating brackish water. Technological progress led to the development of an RO membrane enabling single-pass seawater desalination. Toyobo succeeded in developing a single-pass seawater desalination RO module composed of hollow fiber type membranes made of cellulose triacetate in 1978, and then in 1979 began production of the first commercially available double-element module. This double-element module has many advantages suitable for seawater desalination. It has high chlorine tolerance and high salt rejection, derived from the properties of the membrane material, and it is highly resistant to fouling and scaling matters due to the unique flow pattern and fiber bundle configuration. These advantages help to explain why the Toyobo double-element module has been used so successfully at the many seawater desalination plants around the world. Since the 1980s, large plants capable of desalinating several tens of thousands of cubic meters a day have sprung up around the Mediterranean and In the Middle East. The Jeddah RO Phase I Plant, which has a capacity of 56, 800m$^3$/day, went into operation in 1989. In 1994, the same sized Phase II Plant came on stream, giving the plant a huge total capacity of 113, 600m$^3$/day. The plant constructor Mitsubishi Heavy Industries, Ltd. (MHI), and the RO membrane manufacturer Toyobo Co., Ltd. In 1998, the world's largest RO seawater desalination plant in operation, which has a capacity of 128, 000m$^3$/day and is run by Saudi Arabia's Saline Water Conversion Corporation (SWCC), went into operation at Yanbu. RO seawater desalination technology has thus already reached the stage of full-scale commercial use. In order to encourage its wider use, however, RO desalination needs to be made more economical by lowering construction and water treatment costs. Toyobo has therefore developed a new economical RO desalination system by a recovery ratio of 60% using a high-pressure module with a high product flow rate. In 2000, Toyobo high recovery membrane module was selected for the largest seawater desalination plant in Japan, which has a capacity of 50, 000m$^3$/day.

• Computers and Concrete
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• v.25 no.6
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• pp.485-495
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• 2020

This paper, presents the dynamic and stability analysis of the simply supported single walled Carbon Nanotubes (SWCNT) reinforced concrete beam on elastic-foundation using an integral first-order shear deformation beam theory. The condition of the zero shear-stress on the free surfaces of the beam is ensured by the introduction of the shear correction factors. The SWCNT reinforcement is considered to be uniform and variable according to the X, O and V forms through the thickness of the concrete beam. The effective properties of the reinforced concrete beam are calculated by employing the rule of mixture. The analytical solutions of the buckling and free vibrational behaviors are derived via Hamilton's principle and Navier method. The analytical results of the critical buckling loads and frequency parameters of the SWCNT-RC beam are presented in the form of explicit tables and graphs. Also the diverse parameters influencing the dynamic and stability behaviors of the reinforced concrete beam are discussed in detail.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4459-4464
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• 2012

Background: Breast cancer is one of the leading causes of death among cancer patients in Saudi Arabia. It is known that nurses play a key role in promoting breast cancer awareness among women in any society. Nurses in primary health care centres (PHCC) have more direct contact with general population. This study aimed to investigate nurse knowledge of breast cancer and practice of early screening in PHCC in Jeddah city. Methods: A cross-sectional study was conducted using a self-administered questionnaire to assess the general knowledge of breast cancer, risk factors, and practice of 210 PHCC nurses. Data were analysed using SPSS v.16. Results: The mean age of the PHCC Nurses was 36.9 (SD ${\pm}8.6$). Only 11% percent scored <50% of the total score for general epidemiological knowledge on breast cancer, about 35% scored <50% of the total score for breast cancer risk factors. Sixty seven percent scored >75% of the total score on breast cancer signs. Majority of nurses 62.8% practiced BSE, but only 4% practiced regularly every month. Some 28% practiced once per year. About 81% of the nurses had not had a clinical breast examination and only 14% had had a mammography. The results of the study failed to show any correlation between the knowledge scores with age, education, year of experience, family history of BC and marital status of the nurses. Conclusion:The results from the study reflect that there is a need to provide continuing nursing education programmes for PHCC nurses to improve their breast cancer knowledge and practice.

• Geomechanics and Engineering
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• v.21 no.5
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• pp.471-487
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• 2020

In this work, the buckling analysis of material sandwich plates based on a two-parameter elastic foundation under various boundary conditions is investigated on the basis of a new theory of refined trigonometric shear deformation. This theory includes indeterminate integral variables and contains only four unknowns in which any shear correction factor not used, with even less than the conventional theory of first shear strain (FSDT). Applying the principle of virtual displacements, the governing equations and boundary conditions are obtained. To solve the buckling problem for different boundary conditions, Galerkin's approach is utilized for symmetric EGM sandwich plates with six different boundary conditions. A detailed numerical study is carried out to examine the influence of plate aspect ratio, elastic foundation coefficients, ratio, side-to-thickness ratio and boundary conditions on the buckling response of FGM sandwich plates. A good agreement between the results obtained and the available solutions of existing shear deformation theories that have a greater number of unknowns proves to demonstrate the precision of the proposed theory.

• Geomechanics and Engineering
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• v.22 no.2
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• pp.119-132
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• 2020

In this study a new innovative three unknowns trigonometric shear deformation theory is proposed for the buckling and vibration responses of exponentially graded sandwich plates resting on elastic mediums under various boundary conditions. The key feature of this theoretical formulation is that, in addition to considering shear deformation effect, it has only three unknowns in the displacement field as in the case of the classical plate theory (CPT), contrary to five as in the first shear deformation theory (FSDT) and higher-order shear deformation theory (HSDT). Material characteristics of the sandwich plate faces are considered to vary within the thickness direction via an exponential law distribution as a function of the volume fractions of the constituents. Equations of motion are obtained by employing Hamilton's principle. Numerical results for buckling and free vibration analysis of exponentially graded sandwich plates under various boundary conditions are obtained and discussed. Verification studies confirmed that the present three -unknown shear deformation theory is comparable with higher-order shear deformation theories which contain a greater number of unknowns.

• Water for future
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• v.8 no.2
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• pp.30-40
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• 1975

Hydrogeological survey and geophysical prospecting have been carried out in Saudi Arabia for the purpose of finding groundwater in the soil and rock at the request of General trading company in Jeddah, Saudi Arabia. The surveyed area is located on $38^{\circ}-39^{\circ}$ 30' in longitude and $26^{\circ}-26^{\circ}$ 30' in latitude. The topography of this area is dominated by northwest southeast mountain range composed mostly of precambrian rocks and basalt of tertiary period. Geology is mainly composed of greenstone, granite, andesite, diorite rhyolite of pre-cambrian era and sandstone of cambrian period which are underlained by basalt and andesite of tertiary period and alluvium of quaternary unconformably. The instruments used in this investigation are TR-18B2 radioactivity unit which isjapanese patented and A.C. Terrameter, a resistivity meter manufactured by ABEM of Stockholm, Sweden. Radioactivity method has been conducted along the Alula-Khaybar road, totally 164Km by the car-borne. As a result of the above survey 16 places have been selected and these anomalies show 1.2N-1.6N compared to background of each area in intensity with width of 10-50m. Resistivity vertical profiling which made use of Schlumberger configuration method has been made over selected areas by radioactivity method to provide hydrogeological information for a water resources survey. The result of resistivity shows that good aquifers are located in the western part of surveyed area where sedimentary rock is distributed. The strata showing 10-50, ${\Omega}-m$ in resistivity are thought to be waterbearing layer. The variations in aquifer resistivity found, are thought to be due to verying clay content, which could be related to aquifer yield. It has proved impossible to detect small salinity variation in the buried aquifer by geophysics. As a result of resistivity prospecting 10 places are recommended to be drilled at the anomalies as shown attached map. yields from the proposed holes have been estimated approximately from $20m^3$ to $200m^3$ per day. Prior to drilling for groundwater, test boring using ${\c}4"$ should be drilled in order to obtain more reliable hydrogeological information for the construction of perfect wells.ells.

• Computers and Concrete
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• v.26 no.2
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• pp.185-201
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• 2020

This research is devoted to investigate the bending and free vibration behaviour of laminated composite/sandwich plates and shells, by applying an analytical model based on a generalized and simple refined higher-order shear deformation theory (RHSDT) with four independent unknown variables. The kinematics of the proposed theoretical model is defined by an undetermined integral component and uses the hyperbolic shape function to include the effects of the transverse shear stresses through the plate/shell thickness; hence a shear correction factor is not required. The governing differential equations and associated boundary conditions are derived by employing the principle of virtual work and solved via Navier-type analytical procedure. To verify the validity and applicability of the present refined theory, some numerical results related to displacements, stresses and fundamental frequencies of simply supported laminated composite/sandwich plates and shells are presented and compared with those obtained by other shear deformation models considered in this paper. From the analysis, it can be concluded that the kinematics based on the undetermined integral component is very efficient, and its use leads to reach higher accuracy than conventional models in the study of laminated plates and shells.

• Computers and Concrete
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• v.26 no.3
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• pp.213-226
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• 2020

The present study covenants with the static and free vibration behavior of nanocomposite sandwich plates reinforced by carbon nanotubes resting on Pasternak elastic foundation. Uniformly distributed (UD-CNT) and functionally graded (FG-CNT) distributions of aligned carbon nanotube are considered for two types of sandwich plates such as, the face sheet reinforced and homogeneous core and the homogeneous face sheet and reinforced core. Based on the first shear deformation theory (FSDT), the Hamilton's principle is employed to derive the mathematical models. The obtained solutions are numerically validated by comparison with some available cases in the literature. The elastic foundation model is assumed as one parameter Winkler - Pasternak foundation. A parametric study is conducted to study the effects of aspect ratios, foundation parameters, carbon nanotube volume fraction, types of reinforcement, core-to-face sheet thickness ratio and types of loads acting on the bending and free vibration analyses. It is explicitly shown that the (FG-CNT) face sheet reinforced sandwich plate has a high resistance against deflections compared to other types of reinforcement. It is also revealed that the reduction in the dimensionless natural frequency is most pronounced in core reinforced sandwich plate.

• Steel and Composite Structures
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• v.34 no.5
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• pp.643-655
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• 2020

In the present work, the buckling behavior of a single-layered graphene sheet (SLGS) embedded in visco-Pasternak's medium is studied using nonlocal four-unknown integral model. This model has a displacement field with integral terms which includes the effect of transverse shear deformation without using shear correction factors. The visco-Pasternak's medium is introduced by considering the damping effect to the classical foundation model which modeled by the linear Winkler's coefficient and Pasternak's (shear) foundation coefficient. The SLGS under consideration is subjected to compressive in- plane edge loads per unit length. The influences of many parameters such as nonlocal parameter, geometric ratio, the visco-Pasternak's coefficients, damping parameter, and mode numbers on the buckling response of the SLGSs are studied and discussed.

• Advances in nano research
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• v.8 no.4
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• pp.293-305
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• 2020

In the current research, the free vibrational behavior of the FG nano-beams integrated in the hygro-thermal environment and reposed on the elastic foundation is investigated using a novel integral Timoshenko beam theory (ITBT). The current model has only three variables unknown and requires the introduction of the shear correction factor because her uniformed variation of the shear stress through the thickness. The effective properties of the nano-beam vary according to power-law and symmetric sigmoid distributions. Three models of the hygro-thermal loading are employed. The effect of the small scale effect is considered by using the nonlocal theory of Eringen. The equations of motion of the present model are determined and resolved via Hamilton principle and Navier method, respectively. Several numerical results are presented thereafter to illustrate the accuracy and efficiency of the actual integral Timoshenko beam theory. The effects of the various parameters influencing the vibrational responses of the P-FG and SS-FG nano-beam are also examined and discussed in detail.