DIYALA JOURNAL OF ENGINEERING SCIENCES

Quantum well infrared photodetector (QWIP) become one of the important devices recently for their efficient, stability, uniformity, and high intrinsic speed. The photodetector was designed, and the validity, absorption coefficient, and band transitions are studied extensively. The quantum wells included in this research operate in mid infrared wavelength region (9-11 μm). Results showed that peak absorption coefficient at (10.6 μm) is (9000 cm-1) for Bound –bound transition and is more narrow and intense from bound-continuum transition (1800 cm-1) and the quantum well based devices can be used to detect such wavelength providing that the external electric field stays below a reasonable value. This makes such device a promising solution for MIR applications.

This paper presents a miniaturized dual-band bandpass filter using two coupled dual-mode resonators (DMRs).The dual-mode resonator is a short-circuited stub loaded square loop resonator.The concept of miniaturization achieved using multilayered technology. Therefore, the filter circuits are achieved in three layers. On the first layer, two coupled dual-mode resonators are designed and shorted to a ground layer to specify the required passbands. Next, a second layer employs two shorted quarter wavelength stubs coupled through one via hole are capacitively coupled to the first layer circuit to achieve the filtering response. For our demonstration, a multi-band bandpass filter is designed to serve a multifunctional wireless system has centre frequencies of 1.9 GHz GSM and 3.5 GHz WiMax systems. The filter is implemented and simulated using the momentum simulator of the Advanced Design System(ADS) software package. The filter response has two second-order passbands with four transmission zeros leads to a high skirt selectivity. The filter circuit area is very small, less than 37 mm2 terminating the feeding ports

This paper investigates the ovalisation behavior of the Steel Circular Hollow Sections (CHSs) when subjected to bending moment. The experimental program included testing of ten specimens in four groups in order to examine the influence of changing the diameter, thickness, length and the presence of openings on the ovalisation phenomenon of these specimens.The experimental results showed that the ovalisation of the specimen cross-section appears clearly when the diameter to thickness ratio (D/t) is ranging from 17 to 50, while the ovalisation of the specimens that have D/t ratio greater than 50 is very little or unclear because the instability of these specimens are controlled by the local buckling. In addition, the change of the specimen length and the presence of openings didn’t cause the cross-section ovalisation

After increasing the wheel of progress obviously in recent years in all areas, especially in urban planning projects. This led to the increasing need for a scientific and developing method to organize data processing by choosing the optimized master plan for cities. So, the importance of the process of selecting the optimized master plan of economic, environmental and social because of the indirect contact with the people, so the need arises to seek for the best methods that assist in the evaluation and selection of urban planning projects and decision-making by selecting the optimized master plan. One of the methods is the Fuzzy AHP and Fuzzy TOPSIS. This research concentrates on Fuzzy TOPSIS technique which helps to make the best decisions through choosing the optimized master plan for cities. This research aims to evaluate the alternatives to master plan of cities and select the best ones. To achieve the objectives of the research, the data collected from the literature reviews that dealtwith themes of urban planning and Fuzzy TOPSIS techniqueas well as the personal interviews with specialists. The results showed through the data analysis of the sample that the third alternative (Muqdadiyah urban and agricultural center) has received the largest relative importance compared to other alternatives. In the end, a set of conclusions and recommendations were drawn such as the absence of an administrative system capable of evaluating and selecting the optimized master plan with less time and cost. It was found through using the technical research that time and cost of the evaluation and selection obviously significantly were reduced among the alternatives.Corrosion inhibition of low carbon steel, stainless steel types 316 and 304 in hydrochlo

Constitutive models play an important origin in the geotechnical problems design. In order to make the models useful to geotechnical engineers, some numerical predictions are presented to compare the performance of different models with experimental results (Full scale tests). It was found from this study that hardening soil model (HS small model) gave good prediction of settlement more than hardening model and Mohr-Coulomb model. Also, the errors in prediction of maximum settlement pile raft, pile group and raft are ranged (3-4) %, (6-7) % and (27-36) %for hardening soil with small strain model, hardening model and Mohr-Coulomb model respectively

The goal of this research was to design and evaluate the efficiency of horizontal sedimentation tank for water treatment using different position of baffles. Turbid water was treated using alum in the condition with and without baffle in the settling unit. Turbidity was the main determinant in assessing the effectiveness of the settling tank processes. Visualization and profiling research was done using a dye tracer. Samples were collection at different baffle horizontal and vertical height, different flow rates and turbidity with respect to time. Baffle position was found to be capable of increasing turbidity removal efficiency considerably in the settling tank by diminishing the surface loading rate and increasing the retention time. Simulation displayed that turbidity can be eliminated higher than 95%. The type of water purified using optimum position of baffle was well below the WHO guideline for drinking water of <5 NTU

A novel curing agent (1,4-diaminobenzene) was used to enhance behavior of the epoxy resin system. The effect of the curing agent content (12 to 21 wt%) subjected to the isothermal curing temperatures at 80 °C to 110 °C were performed. Results indicate that the gel time was effected slightly on the viscosity when the curing temperature was higher than 90 °C and curing material consist over from 18wt %. These results explain that reaction rates caused by higher curing temperature

The request depending on electrochemical machining (ECM) technique has progressed in a large scale according to different points of view such that; cost or energy consuming, environment protection, reliable performance etc. This work aims to predict and optimize ECM process parameters for important, economic and applicable material (6061 aluminum)by employing L9 Taguchi method as a design of experiment (DOE) approach. This has led to experimental designing, developing a mathematical model and optimizing the entire ECMoperation. This was carried out by controlling the chosen process variables (voltage, flow rate speed and electrolyte concentration) in order to optimize and predict the responses namely material removal rate (MRR) and dissolution rate. ANOVA, 3D contour graphs and perturbation plots have been employed to identify the analysis of variance of each response as well as to show the significant model terms. The process parameters i.e. voltage, flow rate speed and electrolyte concentration have been ranged to be15-25V, 8-12 l/min and 3.36-7 % respectively. In both cases of MRR and dissolution rate the voltage parameter has seen to be the prominent factor that affects the responses so as to investigate highest value of MRR and dissolution rate, 0.477g/min and 2.149 mm/min, respectively. This has been confirmed due to the results obtained from the ANOVA analysis which shows maximum F-valu for the voltage in the MRR and dissolution rate such that; 921.91 and 1608.34 respectively. But, still there was a considerableenhancement in the MRR and dissolution rate due to the increment in the flow rate speed and electrolyte concentration. Model validation has been carried out and thus the results invistigated that all the considered models were adequate since the residuals in prediction of each response were ignored, because the residuals were semi-matched with the diagonal line.Optimizations of responses were performed in this work numerically by using two types of criteria (restricted and non-restricted). According to these criteria, important increment in the MRR can be obtained which reaches 37%. A considerable enhancement has been obtained in the dissolution rate due to the comparison between the two criteria which results in increment by around 11% as well.

This research presents a technique of an electro optic effect for suggestion model and it optimizes implementation of an electro optics switch using Mat lab simulation program (10). this technique includes design a mathematical model for analysis the effect of tensile stress(y), axial (z)and radial (x)strain on the performance evaluation of an electro optic switch also, it analysis an effect the change of length L and width w of arm of switch. Finally,an active switch optimizes, using the analytical model and considers important device in the modern optical communication system

The output of pulse code modulation (PCM)encoder isstatistically described;this description isused at the receiver to reduce the errorof the received signal. Recently, PCM is the most important form of pulse modulation. Bit errors occurat the transmission of information through thecommunication system and the amount of error dependson the characteristics of the channel.In this paper,the voice message is sampled greater than Nyquist rate and quantized with scalar quantizer, then the quantized levels are encoded with resolution Bbitsassigned to each level. The binary data are mappedand transmitted over Gaussian noise channel. The systemwas designed without channel coding. At the receiverthe statistical description isexploited to conceal the errors. Theresults showthat a significant improvement gained in bit error rate that was reduced from 0.078 to 0.052 at 0dBofEbN0⁄by soft decoding, compared to hard decoding.

Mobile ad hoc networks (MANETs) are characterized by the absence of centralized management and the lack of any infrastructures. The frequent topology changes and variable propagation conditions make a routing is the most important issue, therefore, it becomes necessary for nodes within the networks to use appropriate routing algorithms. In this paper, we evaluate the performance of AODV, DSR, OLSR and GRP routing protocols using OPNET modeler 14.5 simulation software. In the simulated mobile ad hoc network, we made all nodes receiving FTP traffic from a FTP server as common source. we increased the possibility of multi-hop routes between nodes with each other or from the server to the nodes by placing them randomly in the network. Our simulations have suggested many of the scenarios to all selected protocols in the identical environmental conditions so as to evaluate their performance with respect to routing overhead, throughput, end-to-end delay and routing load

The study of slope stability is important in the design and construction of the earth dams under influence of special states. Some factors affect on the slope stability for the earth dams such as change the water level in the reservoir, dam configuration, material properties..etc. In this study, the factor of safety of upstream slope stability for number of exist earth damshas been assessed. To achieve the objective of this study, Geo-SLOPE/W program that based on limit equilibrium methods was used. Taking into account the case of dry condition and gradually rise of water level in upstream part for these dams. It can be seems that the slope stability of the earth dams increased in case of dry condition. In addition, the slope stability increased when the water reach to maximum value.