MSF Desalination: Modeling, Simulation, and Economic Study

Some data was collected and reported for seawater desalination in the gulf region. Some information is also given regarding the multi–stage flash (MSF) desalination plants in the United Arab Emirates. The total installed capacity of these plants is 518 MIG. It was revealed that the water demand in the Abu Dhabi Emirate alone has increased by 30 folds during the last 25 years. A literature survey was conducted mainly on modeling and simulation of MSF desalination processes. A number of commercial software such as Speedup, Camel, and EvapoLund were reviewed with special emphasis on EvapoLund that has been used as the process simulation tool in the thesis. Brief descriptions are given for different multi-stage flash desalination processes including single-stage MSF, once – through MSF, brine - mix MSF, and conventional brine - recycle MSF. Two MSF desalination plants at the Al-Taweelah dual-purpose power and desalination complex in Abu Dhabi were selected for study. Both are similar to each other, but designed, built and installed by different companies. The main objective was to check some of the design data provided by the contractor and to evaluate the plant performance at fouled operating conditions. A brief mathematical background is given including mass and energy balances, and rate equations for the conventional brine - recycle MSF process. The simulation results obtained, using the commercial software EvapoLund, revealed some discrepancies for one of the plants is chosen as case study and rather good resemblance for the other plant. It was also established that acid wash for one of the plants was needed to restore the value of its overall heat transfer coefficients to the design values. The U-values for the other plant were computed using design data at clean and fouled conditions. Using some data available from the contractor, an economic evaluation was made to establish the real unit production cost. The annual capital cost, annual operating cost, and the water unit cost were calculated as 0.39, 1.16, and 1.55 $/m3, respectively. The last figure is equivalent to 5.72 Dhs/m3

Morphological, syntactic and diacritics rules for automatic diacritization of Arabic sentences

AbstractThe diacritical marks of Arabic language are characters other than letters and are in the majority of cases absent from Arab writings. This paper presents a hybrid system for automatic diacritization of Arabic sentences combining linguistic rules and statistical treatments. The used approach is based on four stages. The first phase consists of a morphological analysis using the second version of the morphological analyzer Alkhalil Morpho Sys. Morphosyntactic outputs from this step are used in the second phase to eliminate invalid word transitions according to the syntactic rules. Then, the system used in the third stage is a discrete hidden Markov model and Viterbi algorithm to determine the most probable diacritized sentence. The unseen transitions in the training corpus are processed using smoothing techniques. Finally, the last step deals with words not analyzed by Alkhalil analyzer, for which we use statistical treatments based on the letters. The word error rate of our system is around 2.58% if we ignore the diacritic of the last letter of the word and around 6.28% when this diacritic is taken into account

Morphological and Physiological Abnormalities in Tissue Culture-Derived Date Palm (Phoenix dactylifera L.) Plants

The UAE attaches great importance to agricultural development with a sound focus on date palms. This special attention is obvious in the ongoing expansion of agricultural resources and investments, the growing number of palm trees, and in the extensive use of modern technologies. Mass cultivation of date palm trees is required to continue according to the country\u27s agricultural plans. In order to achieve these agricultural expansion of date palm, new techniques of propagation other than traditional techniques (seed and offshoot propagation) are critically required. Tissue culture is a modern and reliable technology being one of the main methods for date palm propagation. However, such technique seems to be expensive and has a few problems that still need to be studied carefully. Trueness-to-type and appearance of abnormalities are the most serious problems associated with the tissue culture derived plants. These problems can be solved and perhaps eliminated by further study on developing the conditions used in this technique. The aim of the present investigation is to study the morphological abnormalities in tissue culture-derived date palm plants and to relate these abnormalities to the applied conditions during the in vitro multiplication process. These results will contribute to avoiding such shortcomings in the future and avoid the occurrence and propagation of such abnormalities

Anomalous Behavior of the Diffusion Coefficient in Interacting Adsorbates

Langevin simulations provide an effective way to study collective effects of Brownian particles immersed in a two-dimensional periodic potential. In this paper, we concentrate essentially on the behaviour of the tracer (DTr) and bulk (DB) diffusion coefficients as function of friction. Our simulations show that in the high friction limit, the two physical quantities DTr and DB present qualitatively the same behaviour, for both coupled and decoupled substrate potentials. However, for the low friction regime, and especially for the coupled potential case, an anomalous diffusion behaviour is found. We also found that in the case of weak dynamical coupling between the ad-particles and the substrate, the exponents are not universal and rather depend on the potentials. Moreover, changes in the inter-particle potentials may reverse the behaviour to a normal one

Study of surface diffusion by Langevin Dynamics simulation

We investigate the dynamic properties of Brownian interacting particles subject to a two-dimensional periodic potential. By employing the Langevin dynamics simulation, we calculate the collective diffusion coefficient in different situations corresponding to different densities. On the other hand, our numerical studies show that the collective diffusion coefficient depends not only on the shape of adsorbed potential but also on the coupling between particles.We investigate the dynamic properties of Brownian interacting particles subject to a two-dimensional periodic potential. By employing the Langevin dynamics simulation, we calculate the collective diffusion coefficient in different situations corresponding to different densities. On the other hand, our numerical studies show that the collective diffusion coefficient depends not only on the shape of adsorbed potential but also on the coupling between particles

The chemotherapeutic agent bortezomib induces the formation of stress granules

BACKGROUND: Cytoplasmic stress granules (SGs) are specialized storage sites of untranslated mRNAs whose formation occurs under different stress conditions and is often associated with cell survival. SGs-inducing stresses include radiations, hypoxia, viral infections, and chemical inhibitors of specific translation initiation factors. The FDA-approved drug bortezomib (Velcade(®)) is a peptide boronate inhibitor of the 26S proteasome that is very efficient for the treatment of myelomas and other hematological tumors. Solid tumors are largely refractory to bortezomib. In the present study, we investigated the formation of SGs following bortezomib treatment. RESULTS: We show that bortezomib efficiently induces the formation of SGs in cancer cells. This process involves the phosphorylation of translation initiation factor eIF2α by heme-regulated inhibitor kinase (HRI). Depletion of HRI prevents bortezomib-induced formation of SGs and promotes apoptosis. CONCLUSIONS: This is the first study describing the formation of SGs by a chemotherapeutic compound. We speculate that the activation of HRI and the formation of SGs might constitute a mechanism by which cancer cells resist bortezomib-mediated apoptosis

Diffusion in Inhomogeneous Systems: Self-Consistent Random Phase Approximation

The classical diffusion of particles in an inhomogeneous periodic system is studied employing the Fokker-Planck equation. The full width at half-maximum (fwhm) of the quasielastic peak in the dynamic structure factorS(q,ω) is calculated numerically by the matrix continued fraction method up to large values of the momentum transfer covering several Brillouin zones. It is shown that fwhm exhibits strong oscillations with the scattering wave-vector q as it has been observed in β-Ag 2 S by the mean of neutron scattering.The classical diffusion of particles in an inhomogeneous periodic system is studied employing the Fokker-Planck equation. The full width at half-maximum (fwhm) of the quasielastic peak in the dynamic structure factorS(q,ω) is calculated numerically by the matrix continued fraction method up to large values of the momentum transfer covering several Brillouin zones. It is shown that fwhm exhibits strong oscillations with the scattering wave-vector q as it has been observed in β-Ag 2 S by the mean of neutron scattering

Fokker Planck Dynamic in a Periodic Triple-Well Potential

In this work we present a general theory for diffusion mechanism of Brownian particle submitted to a symmetric and periodic triple-well potential (Fig 1). The kinetics description is done with a Fokker-Planck equation (F.P.E). The F.P.E is resolved numerically using the Matrix Continued Fraction Method (M.C.F.M).In order to calculate some important correlation functions. The half-with of the quasi-elastic line λ(q) of dynamic structure factor S (q,w) is studied in the high friction regime and low temperature for different structure of potential with a fixed barrier potential The result show that the half with λ(q) present the same aspect for different values of the ratio of two potential barriers Δ (Δ=V1/V2), except for Δ≈1 for which λ(q) is a cosine function.In this work we present a general theory for diffusion mechanism of Brownian particle submitted to a symmetric and periodic triple-well potential (Fig 1). The kinetics description is done with a Fokker-Planck equation (F.P.E). The F.P.E is resolved numerically using the Matrix Continued Fraction Method (M.C.F.M).In order to calculate some important correlation functions. The half-with of the quasi-elastic line λ(q) of dynamic structure factor S (q,w) is studied in the high friction regime and low temperature for different structure of potential with a fixed barrier potential The result show that the half with λ(q) present the same aspect for different values of the ratio of two potential barriers Δ (Δ=V1/V2), except for Δ≈1 for which λ(q) is a cosine function