Vol. 6 No. 2 (2013)
Articles
Abstract: The modeling and control of genetic regulatory networks carries tremendous potential for gaining a deep understanding of biological processes, and for developing effective therapeutic intervention in diseases such as cancer. A dynamical programming control has been proposed for determining an optimal intervention policy to shift the steady-state distribution of the network. The dynamic programming solution is, however, computationally prohibitive for large gene regulatory networks, as its complexity increases exponentially with the number of genes. Since the number of genes considered is directly related to the accuracy of the model, it is imperative to be able to design optimal intervention policies that can be reasonably implemented for large gene regulatory networks. To this endeavor, we will design a neural dynamic programming controller to optimize the same dynamic programming performance measure, while requiring only a polynomial time complexity. The proposed neural dynamic programming structure includes two networks: action and critic. The critic network is trained toward optimizing a total reward to objective, namely to balance the Bellman equation. The action network, constrained by the critic network, generates the optimal control strategy. Both the control strategy and the critic output are updated according to an error function that changes from one step to another. General theory of non-homogeneous Markov chain will be used to find the optimal strategies of non uniform policy method.
Abstract: In this paper, the free overfall in rectangular channel with a different slopes and bed rough distribution was studied. Bed roughness was made of wood allocated in three different cases: two, three and zigzag rows. The aim of this study is to obtain discharge equations for free overfall depending on brink depth and slope. Three empirical equations proposed for calculating discharge. These equations influenced by slope, channel bed roughness as well as method of roughness distribution. Three rows bed roughness having grater effect on these relationships at steeper slopes. the average values of hc/he at smooth bed is greater by (4%) with respect to that for bed rough at two rows, by (19%) with respect to that for bed rough at zigzag rows and by (24%) with respect to that for bed rough at three rows, so that values for three rows rough and horizontal channel is greater by (4%) with respect to that for channel slope at (1/200) and by (14%) with respect to that for channel slope at (1/100).
Abstract: This research deals with the effect of rice husk ash (RHA) and Metakaolin (MK) as a partial replacement for ordinary Portland cement (OPC) on properties of self – compacting concrete (SCC). Three different replacements of RHA ( 5% , 10% and 15%) and one replacement of Metakaolin (15%) were used for SCC. To determine the workability, three test methods were adopted, slump_flow, L.box and V_funnel. The experimental results showed that (RHA) improved the strength and modulus of elasticity of SCC at age after 60 days . The optimum strength was at 15% replacement . Specimens with 15 % replacement of ( MK) showed a better strength and modulus of elasticity at all ages . Also the use of( RHA and MK) caused reduction in water absorption and increase the ultrasonic pulse velocity.
Abstract: Array of silicon nanorods with a circular cross section onto Mo nanopillars arrangement were grown using glancing angle deposition (GLAD) on Si (100).Deposition technique was used to fabricate Mo thin film on silicon flat surface. Teflon deposited on the tips of Mo nanorods at normal incident evaporation (θdep.is 0oC) with deposition time of (5 min.) to study the hydrophoposity and hydroplilicity of the surface. Morphology of Mo and Mo/Teflon nanocomposite was carried out using scanning electron microscope (SEM) which indicates a (100 nm) of mo thin film and Mo nanorods on silicon substrate. Contact angle measurement on nanocomposite Mo nanorods with Teflon grown on their tips exhibited contact angle values as high as (116o) indicating an increase in the hydrophopocity of original hydrophilic Mo nanostructures that had an angle of (40o).
Abstract: This study describes the process of analysis of a piled raft foundation for a high rise residential building (Burj al-Amir) on the Najaf Sea in Iraq. Piled raft foundation is a foundation used, in which the total load coming from the super structure is transferred to the soil by a load sharing mechanism between raft and pile. The present study attempts to do a three dimensional finite element analysis of piled raft foundation subjected to vertical load using PLAXIS program. Various tests are done to explore soil properties, also parametric study to find effect the piled raft dimensions include pile spacing, number of piles, pile diameters, pile lengths for pile groups, raft thickness and raft dimension ratio (L/B) on piled raft foundation behavior are considered. It has been found that the maximum settlement of the piled rafts depends on the pile spacing and the number of piles.. The maximum bending moment in raft increases with increase raft thickness, decrease pile number and decrease in pile length. Maximum and differential settlement decreases with increase raft thickness and uniform increase in pile length. In the scope of this study, the results of the parametric study are presented and design strategies for piled rafts are discussed
Abstract: The effect of stress concentration and deflection in plates with circular holes subjected to concentrated load is studied. Different hole sizes and distance from the plate center (x) are tested experimentally and compared with a reference plate without hole. The specimens are classified into two groups, the first represents specimens containing hole leis in the x-axis of the plate group (A) , and the second group represents the specimens containing two half hole leis at the edge of plate group (B). The results are analyzed using finite element method (FEM), which gives good agreement with the experimental deflection data. The specimens which have central hole group (A) or side two half hole with the same diameter group (B) give lower deflection than that the plate without hole for the same cross sectional area. Increasing hole diameter gives a reduction in the deflection values for each specimen. Group (B) give a higher deflection value for a wide range of (x) as comparing with those of hole specimens group (A). The maximum stress (σx) is higher in groups as comparing with the reference plate for wide range of (x). When this distance (x) increased, the value of maximum stress is reduced for groups. The same behavior is found when increasing the hole diameter.
Abstract: A pollutant of concern to the mankind is the exhaust noise in the internal combustion engine. However this noise can be reduced sufficiently by means of a well designed muffler. The suitable design and development will help to reduce the noise level. The author design and fabricate a reactive muffler, spherical and cylinder shapes, afterward compared the noise level for these shapes with parallel and series connections. Transmission loss and transmission coefficient are calculated experimentally and theoretically for one, double and three mufflers in parallel and in series. Exhaust noise levels will aid the manufacturer in determining the correct muffler to meet the required noise reduction. These mufflers tested in frequency ranging between (50-600) Hz. In this study, the rustles show that the parallel connection is best than the series connection.
Abstract: In this paper the effect of double quenching heat treatment on microstructure and dry sliding wear behavior of low carbon dual phase steel with carbon concentration (0.0977% C) was investigated. The specimens were intercritically heat treated at different temperatures and then water-quenched. The martensite volume fraction in the double quenched specimens was higher than that of the single quenched specimens. Hardness test was conducted on low carbon steel specimens using Brinell hardness test. Optical microscopy was employed to examine the microstructure of the specimens. Wear test were carried out on the single and double quenched specimens under dry sliding wear condition using a pin-on-disk machine at different loads with constant sliding time and speed, and at different sliding time with constant loads and speed. The experimental results showed that the wear rate effectively decreased in the double quenched specimen.
Abstract: The integration of wireless and optical networks is a potential solution for the increasing capacity and mobility as well as decreasing costs in the access networks. Optical networks are fast, robust and error free, however, there are nonlinearity obstacles preventing them from being perfect media. The performance of wavelength division multiplexing (WDM) in radio over fiber (RoF) systems is found to be strongly influenced by nonlinearity characteristics in side the fiber. The effect of four wave mixing (FWM) as one of the influential factors in the WDM for RoF has been studied here using Optisystem and Matlab. From the results obtained, it is found that the FWM effects have become significant at high optical power levels and have become even more significant when the capacity of the optical transmission line is increased, which has been done by either increasing the channel bit rate, and decreasing the channel spacing, or by the combination of both process. It is found that when the channel spacing is 0.1 nm, 0.2 nm and 0.5 nm the FWM power becomes about -59dBm to -79dBm respectively. This result confirms that the fiber nonlinearities play decisive role in the WDM for RoF system. The simulation results obtained here are in reasonable agreement as compared with other numerical simulation results obtained, elsewhere, using different simulation tools.
Abstract: The aim of this study is reduce the evaporation rate from dry-wet cooling tower combination system through using different shapes and different arrangements between dry and wet cooling towers. Four shapes of corrugated packing were used in the study with all arrangements combination between dry and wet cooling towers in order to get the shape that give minimum evaporation rate (loss). Four arrangements combination of dry-wet cooling tower, two of arrangement were series (AS1, and AS2), and two of arrangements were parallel (AP1, andAP2). The variables for this study were obtained from North Oil Company (N.O.C.) in the Ministry of Oil of Iraq; these data included temperatures, flow rate, packing types, ambient conditions, pressure, and fan parameters. The results show that AS1 configuration produces lower evaporation rates by about 58 % reducing in percent, and then followed by the other configuration. The corrugated types 1 and 4 gives the minimum amount of evaporation losses then the other types of corrugated by about 40 %. The corrugated types 1 and 4 operated with a minimum cost of operation