Effect of skew angle on behavior of simply supported R. C. T- beam bridge decks

Ibrahim S. I. Harba

T-beam Bridge is a common choice among the designers for small and medium span bridges. In order to cater to greater speed and more safety of present day traffic, the modern high ways are to be straight as far as possible. This requirement, along with other requirements for fixing alignment of the bridges, is mainly responsible for provision of increasing number of skew bridges. The presence of skew in a bridge makes the analysis and design of bridge decks intricate. For the T- beam bridges with small skew angle, it is frequently considered safe to ignore the angle of skew and analyze the bridge as a right bridge with a span equal to the skew span. However, T-beam bridges with large angle of skew can have a considerable effect on the behavior of the bridge especially in the short to medium range of spans. In this paper an analytical study using three dimensional finite element methods was performed to investigate the effect of skew angle on behavior of simply supported reinforced concrete T-beam bridge decks. The parameters investigated in this analytical study were the span lengths and skew angle. The finite element analysis (FEA) results for skewed bridges were compared to the reference straight bridges (nonskewed). The geometric dimensions of the T-beam bridge decks and the loading used are in compliance with AASHTO standard specifications. The FEA results and comparison of skewed bridge with straight bridge indicate that max. Live load bending moments and deflections decreases in T- beams for skewed bridges, while max. shear, torsion and supports reactions increases in some T-beams for skewed bridges for all considered span lengths (12, 16, 20 and 24m). This study disagreement with the AASHTO standard specifications as well as the LRFD in recommending that bridges with skew angle less than or equal 20° be designed as straight (non skewed) bridges also it recommended that engineers are better to perform three dimensional finite element analysis for skewed T-beam bridge decks.

Beam width enhancement of L1 and L5 of global positioning system (GPS) antenna

Ahmed Al-Shaheen

In this paper we enhance the beam width for Global Positioning system (GPS) application rectangular patch microstrip antenna for two designs at L1 centered at 1.75742 GHz and L5 centered at 1.17642 GHz. Tow antennas are mounted on the hexa-pyramidal ground plane to utilize for broadening the beam width for wide coverage area with circularly polarized radiation pattern, the antenna substrate is FR4 of e_r = 4.4 with thickness of 3.2 mm. The parametric study has been done to choose the optimum parameters for the top ground plane, base of ground plane, and drooped angle, the yielding results of this study shows that the beam width is up to 160° and 170° for E-plane and H-plane respectively, with a gain of -1.2 dB for RHCP radiation pattern at resonance frequency of 1.575 GHz antenna at top ground plane 40 mm and base ground plane 125 mm and 50° for drooped angle. While, for the beam width is up to 150° and 160° for E-plane and H-plane respectively, with a gain of -1.67 dB for RHCP radiation pattern at resonance frequency of 1.176 GHz antenna at top ground plane 60 mm and base ground plane 150 mm and 60° for drooped angle. The results are compared with the traditional rectangular patch microstrip antenna for the GPS application. The band width is 43 MHz and 54.7 MHz for to 1.57542 GHz and 1.17642, respectively.

Design and fabrication of equipment for low velocity impact testing of composite sandwich panels

Ramesh S. Sharma and V. P. Raghupathy

Polymer composite sandwich panels are being utilized increasingly as primary load-carrying components in aircraft and aerospace structures. Serving in this capacity, these structures are subjected to impacts such as tool drops, hail, bird strikes, and runway debris. Unlike for their solid metallic counterparts, predictions of the effects of low-velocity impact damage are difficult and are still relatively immature. Sandwich panels in particular are sensitive to localized impact. For making a systematic study of impact on composite sandwich panels under these conditions, suitable equipment was designed and fabricated. This article describes the salient features of indigenously developed test equipment for testing localized, penetrating impact on sandwich panels. The size of the sandwich panels in question are 150 X 150 mm2 with a typical thickness of 16-25 mm. The impact velocities are in the region 2 - 6 m/s, with an impactor mass between 2.5 and 12.5 kg, and two types of impactors were used: hemispherical impactor with diameter of 12.5 mm and flat impactor of 25 x 25 mm. Using this equipment laminated composites, sandwich panels and polymer sheets can be tested to assess the resistance to falling weight in the low velocity region. The piezeo - electric sensor of the tester facilitates evaluation of absorbed load and absorbed energy and thus the performance of sandwich structure subjected to single impact, which in turn is useful for the development of useful criteria for materials selection.

Modeling and simulation of the effects of crude oil dispersion on land

M. Abdulkadir and S. Yahaya

This study was carried out to develop a model equation for dispersion of crude oil on land. The developed model equation in this work is Y = 21.81 + 84.50X - 91.40X². The equation was simulated with the aid of MINITAB software. The experimental and model results obtained from the simulation of the model equation were plotted on the same axis against time of dispersion and distance of dispersion. The model results revealed good agreement.

Realistic estimate of agricultural power in Andhra Pradesh, India- A case study

K. Swarna Sri and SVL Narasimham

Abstract:

Energy supply to agriculture is gaining importance in many states in India. Average increase in number of tube wells for irrigation by many folds has raised the agricultural demand on the grid which is not being metered or monitored. This consumption is considered as residue in the process of estimation of Transmission and Distribution (T and D) losses by utilities every year. Hence this paper finds its importance while estimating actual electrical energy consumed by agricultural sector. Experiments are conducted near the pump sets in fields to find actual electricity consumption at various pumping rates. Along with the drawbacks of current methods of arriving at agricultural demand, the paper proposes a conceptual method to estimate actual agricultural energy consumption by agricultural sector. The results are compared with the actual consumptions from Annual Revenue Requirements (ARR) filed by distribution companies of Andhra Pradesh.

Study the effect of flow bypass on the performance of a shrouded longitudinal fin array

Ahmed F. Khudheyer

Abstract:

Theoretical and experimental studies were carried out to investigate the effects of duct velocity, fin density and tip-to-shroud clearance on the flow bypass and its impact on the pressure drop across a longitudinal aluminum fin array and its thermal performance. The clearance was varied parametrically, stating with the fully shrouded case and variations of the channel height giving partially shrouded configuration of different clearance ratios were also carried out. The flow bypass was found to increase with increasing fin density and insensitive to the air flow rate. That effect of fin density decreased as the clearance increased. The calculated total pressure was greatly affected by fin density. For fully-shrouded fin array, with Hf /S equals to 8 and 12.75, the pressure drop increased by a factor of 4.3 and 20 of that with Hf /S equals to 3.4, respectively. The total pressure drop and the average convective heat transfer coefficients corresponding to the fully and partially shrouded fin array of Hf /S = 3.4 were compared. Going from fully to partially shrouded one of the largest clearance ratio (C/Hf = 0.89), the total pressure drop reduced by about 50%. For clearance ratios equal to 0.36, 0.56, and 0.89, the average heat transfer coefficients were reduced by about 12, 17, and 30 percent of those for the fully shrouded configuration at Re_D of about 3 x 10³. That percentage reduction in heat transfer coefficients decreased with the increase of air flow rate.

Mixed convective heat transfer in rectangular enclosures filled with porous media

M. A. Waheed, G. A. Odewole and S. O. Alagbe

The mixed convective heat transfer in a fluid-saturated porous medium has been investigated numerically using the generalized non-Darcy model. The problem governing equations including the continuity, the generalized Darcy-Brinkman-Forchheimer extended momentum and the energy transport equations were thereby solved using the finite difference method. The flow governing parameters including the Darcy, Richardson and Péclet numbers, and the length-to-height aspect ratio were varied in the range 10^-3 ≤ Da ≤ 10, 0.1 ≤ Ri ≤ 10, 1 ≤ Pe ≤ 10³, and 0.5 ≤ AR ≤ 4, respectively while the Reynolds number was held constant at a value of Re = 100 for all computations. The results are presented in the form of the streamlines and isotherms contours, and the profiles for horizontal component of velocity, temperature and the local heat flux. The results show that all the flow governing parameters have strong influence on the flow pattern and heat distribution within the enclosure.

Development of animal drawn rotary tiller

S. M. Nage, B. P. Mishra, A. K. Dave and J. S. Nikhade

Abstract:

Rotary tiller generally refers to breaking down soil aggregates into ultimate soil particles. The degree of clod breaking depends on moisture content, tillage implements and intensity of clod breaking. One unit of animal drawn rotary tiller with L - shapes of blades was developed and fabricated at workshop of Faculty of Agricultural Engineering, Raipur. The effective field capacity of animal drawn rotary tiller (18 blades) was found 0.12 ha/h at a forward speed of 2.5 km/h. The field efficiency of 62.85% was observed during the field performance. The draft requirement of the developed animal drawn rotary tiller is 378 N. Mean Mass Diameter (MMD) of soil clod size was found 28.42 mm. The operational cost was found 384 Rs/ha.

Evaluation of produced water discharge in the Niger-delta

Isehunwa S. O. and Onovae S.

Abstract:

Water produced during petroleum production often contain chemicals, oil and sometimes, naturally occurring radioactive materials which could harm the environment. Management involves significant cost and is guided by strict regulations, is normally aimed at minimizing or reducing the toxicity of discharged volumes. This study evaluated the physico-chemical properties and constituents of produced water from three selected flow stations and two oil terminals in the Niger Delta to determine the extent of compliance with standards and global best practices in the treatment and discharge. It was observed that while physico-chemical properties like pH (8.4±0.25) and BOD (6.2±2.0) were within recommended limits, oil and grease content (60±20), TDS (6200±700) and others exceeded limits. Similarly, ion concentrations of Lead, Nickel, Zinc and Sulphates were within acceptable limits while chloride ions (4100 ±500) exceeded limits. There is therefore the need to improve treatment facilities and procedures, while regulatory agencies must improve current guidelines, ensure proper monitoring and enforcing compliance.

Batch type synthesis of high free fatty acid Jatropha Curcus oil biodiesel- India as supplying country

Sanjay Gandhi Bojan, Senthil Kumaran and Sam Chelladurai

Abstract:

The Jatropha Curcas oil grown and extracted in the rural belts of western ghat section of South India was tested for its physical and chemical properties to determine its suitability as a feedstock for biodiesel production. A compact, simple, 4-litre biodiesel processor was developed locally. The biodiesel processor was capable of producing biodiesel sufficient in quantity for formers in village level to run the commonly used farm engine for producing electricity for agricultural and other purposes. The properties like kinematic viscosity, acid number, specific gravity, Cetane number, etc of the biodiesel produced meet the ASTM standard but the yield quantity was comparatively low (80.50%) because of the high free fatty acid content in the raw Jatropha Curcas oil. The overall efficiency of the biodiesel produced as a fuel in a four stroke diesel engine coupled with a electric generator was high (24.38%) at maximum load conditions compare to raw Jatropha Curcas oil and petro diesel as fuels which gives only 19.6% and 20.11%, respectively shows the possibilities of using biodiesel produced as a fuel in diesel engine.

Transient free convection MHD flow between two long vertical parallel porous plates with variable temperature and mass diffusion

U. S. Rajput and P. K. Sahu

Abstract:

The unsteady MHD transient free convection flow of an incompressible viscous electrically conducting fluid between two infinite vertical parallel porous plates with Variable temperature and mass diffusion has been considered, under the assumption that the induced magnetic field is negligible. Applied magnetic field is fixed relative to the fluid and plates. The Laplace transform method has been used to find the solutions for the velocity, temperature and concentration profiles. The velocity, temperature and concentration profiles have been studied for different parameters like Prandtl number, Schmidt number, magnetic parameter, buoyancy ratio parameter, permeability parameter and time. The value of the skin-friction for different parameters has been tabulated.

Examinations of the performance of a gas lift for oil well production

M. Abdulkadir and S.Yahaya

Abstract:

Gas lift is a method of artificial lift that uses an external source of high pressure gas for supplementing formation gas to lift the well fluids. The primary limitations for gas lift operations are the lack of formation gas or of an outside source of gas, wide well spacing and available space for compressors on offshore platforms. Generally, gas lift is not applicable to single-well installations and widely spaced wells that are not suited for a centrally located power system. Gas lift can intensify the problems associated with production of viscous crude, super-saturated brine, or an emulsion. Old casing, sour gas and long, small - internal diameter flow lines can rule out gas lift operations. Wet gas without dehydration will reduce the reliability of gas lift operations. A model relating the factors affecting potential production rate along the tubing of a gas lift oil well was developed to optimize production using analytical approach. Modified Darcy equation was employed alongside some other equation of flow such as Fanning’s equation, Reynolds’ equation and a host of others which resulted in the developed model equation. Data from four wells were used in applying the model equation and it was found that, for the four wells and the square of the velocity of oil flow is equal to the oil production rate and both vary directly with the difference in pressure between the reservoir and the well bore. This implies, the lower the well bore pressure the higher the oil production rate and oil velocity.

Efficient FPGA implementation of 2nd order digital controllers using Matlab/Simulink

Vikas gupta, K. Khare and R. P. Singh

Abstract:

This paper explains a method for the design and implementation of digital controller based on Field Programmable Gate Array (FPGA) device. It is more compact, power efficient and provides high speed capabilities as compared to software based PID controllers. The proposed method is based on implementation of Digital controller as digital filters using DSP architectures. The PID controller is designed using MATLAB and Simulink to generate a set of coefficients associated with the desired controller characteristics. The controller coefficients are then included in VHDL that implements the PID controller on to FPGA. MATLAB program is used to design PID controller to calculate and plot the time response of the control system. The synthesis report concludes the resource utilization of selected FPGA.

Prediction of vapor liquid equilibrium (VLE) data for binary systems: A case study of methane/tetrafluoromethane

A. R. Moghadassi, M. R. Nikkholgh, S. M. Hosseini, F. Parvizian and A. Sanaeirad

Abstract:

In this research, the ability of multilayer perceptron neural networks to estimate vapor liquid equilibrium data have been studied. Isothermal vapor-liquid equilibrium (VLE) data for the binary mixture of methane (R50) + tetrafluoromethane (R14) have been investigated at (159.61, 161.58, 169.38, 173.90, and 178.93) K. Two different models with one hidden layer consisted of five hidden neurons are developed as the optimal structures. For this binary system, uncertainties of ANN models were 0.14, 0.26%. In addition, the abilities of ANNs are shown by comparisons with Margules, van Laar, and some other correlations.

Mixing time effects on properties of self compacting concrete

M. M. Rahman, M. H. Rashid, M. A. Hossain, F .S. Adrita and T. Hossain

Abstract:

Self Compacting Concrete (SCC) is an innovative concrete that flows under its own self weight. Besides the composition and raw materials of SCC, mixing time has a great influence on the mechanical properties of SCC such as compressive strength, splitting tensile strength, amount of water added and permeability of concrete. These properties vary with general mixing time 5 minutes and extended mixing time 90 and 180 minutes. The observations show that compressive and splitting tensile strength decrease and amount of water added increases with the increase of mixing period of SCC. Furthermore, permeability of SCC also increases with the extended mixing period.

Nodal analysis models of looped water distribution networks

Ioan Sarbu

Abstract:

There are three methods for analyzing flow and pressure distribution in looped water supply networks (the loop method, the node method, the element method) taking into consideration hydraulic parameters chosen as unknown. For all these methods, the nonlinear system of equations can be solved by iterative procedures (Hardy–Cross, Newton–Raphson, linear theory). In the case of extending or rehability distribution networks the unknown parameters being the piezometric heads at nodes, the node method for network analysis is preferred. In this paper is formulated a generalized classic model for the nodal analysis of complex looped systems with nonstandard network components and the solvability of new problems, alongside the determination of pressure state in the system. Also, this paper shows a different approach to this problem by using the method of variational formulations for the development of an improved model based on the unconditional optimization procedures. This model has the advantage that it uses a specialized optimization algorithm which minimizes directly an objective multivariable function without constraints, implemented in a computer program. The paper compares proposed models to the classic Hardy-Cross method, and shows the good performance of these models. Based on these models a study regarding implications of pipe network longtime operation on energy consumption is performed.