New patch antenna for ISM band at 2.45 GHZ

Ahmed Al-Shaheen

In this paper we present a new patch antenna as a hexagonal patch operating in the Industrial Scientific Medical (ISM) frequency band at 2.45 GHz, the proposed antenna is verifying using to different numerical techniques which are Finite Element Method FEM and Method of Moment MoM, the compression results give us good agreement. When human body is presented near the antenna the antenna performance such as S11 and bandwidth are affected, the result demonstrates that the new antenna has negligible effect compared with that of the rectangular patch antenna.

Performance evaluation of diesel engine with oxygenated bio-fuel blends

T. Krishnaswamy and N. Shenbaga

The use of oxygenated bio-fuels like bio diesel and ethanol in combination with diesel is an effective measure to substitute renewable fuels and reduce particulate matter (PM) from in-use diesel vehicles. To study the fuel performance, three oxygenated blend fuel designs containing volumes of 15% ethanol with cetane improver additive, 10% ethanol with 10% bio diesel and 15% ethanol with 20% bio diesel were formed. The physical stability of ethanol diesel blend is studied and phase separation is prevented by adding co solvents like Tetrahydrafuran and bio diesel. To meet stricter emission norms, now diesel engines are fitted with after treatment devices. This paper describes the engine and emission characteristics of the above blend fuels on a 4 cylinder, naturally aspirated light duty diesel engine fitted with diesel oxidation catalyst. The engine test results show that it is feasible to use these blends in diesel engines: the thermal efficiencies of the engine fueled by the blends are comparable with that fueled by diesel, with small increase in fuel consumption, due to the lower heating value of ethanol and bio diesel. The smoke emissions from the engine fueled by the blends are lower than that fueled by diesel owing to the increased oxygen content. The reduction is more at higher loads. The HC and CO emissions are found to be higher at lower loads due to the lower cetane number of ethanol. However, NO emissions depend on load conditions and blend contents.

Optimal capacitor placement for loss reduction in distribution systems using fuzzy and harmony search algorithm

M. Damodar Reddy and N. V. Vijaya Kumar

This paper presents a new two-stage methodology using fuzzy and Harmony search algorithm (HSA) for the placement of capacitors on the primary feeders of the radial distribution systems with an objective to reduce the power losses and to improve the voltage profile. In the first stage, fuzzy approach is used to find the optimal capacitor locations and in the second stage, Harmony search algorithm is used to find the optimal sizes of the capacitors. The proposed method is tested on 15-bus, 33-bus, 34-bus and 69-bus test systems and the results are presented.

Particle swarm optimization based optimal power flow for volt-var control

M. Balasubba Reddy, Y. P. Obulesh and S. Sivanaga Raju

Evolutionary computation (EC) techniques such as genetic algorithms (GAs), utilize multiple searching points in the solution space like PSO. Whereas GAs can treat combinatorial optimization problems, PSO was aimed to treat nonlinear optimization problems with continuous variables originally. Moreover, PSO has been expanded to handle combinatorial optimization problems and both discrete and continuous variables as well. Efficient treatment of mixed-integer nonlinear optimization problems (MINLPs) is one of the most difficult problems in practical optimization. Moreover, unlike other EC techniques, PSO can be realized with only a small program; namely, PSO can handle MINLPs with only a small program. This feature of PSO is one of its advantages compared with other optimization techniques. In this paper, the basic PSO method is combined with Newton’s method, and interior point method for the optimal power flow/volt-var optimization. The results obtained on IEEE 30-bus system showed that the hybrid method based on PSO-IPM gives the best results compared to the other methods proposed in this chapter. It has been demonstrated that the proposed method can be easily applied to large systems.

An approximate theory of static filtration of drilling muds in vertical wells

Isehunwa S. O. and Falade G. K.

Abstract:

The adverse effects of filtrates during oilwell drilling may be reduced if the mechanism of filtration through mud cakes is well understood. Considerable efforts have therefore been made through empirical and theoretical studies to formulate a robust filtration theory for predicting the effects of mud parameters during drilling. Most of the existing models are either too simplistic or rather complex. This study developed a robust approximate analytical filtration theory that incorporated steady state and transient effects. The results show that in addition to viscosity, transient effects during filtration greatly affect cake build-up and filtrate volumes and that reduced filtrate volumes can be achieved when steady state is achieved rather than unsteady state filtration process.

Heat transfer analysis in PCM filled RCC roof for thermal management

M. Ravikumar and P. S. Srinivasan

Abstract:

Analysis of heat transmission across three roof structures viz., bare RCC roof, RCC roof with weathering coarse and RCC roof with PCM (Phase Change Material) above RCC, are analysed. A transient numerical procedure is developed. The numerical procedure is validated against the available experimental data. The simulation is carried out on 365 days of year for these three roofs. The PCM melts from 8h to 18h and solidifies during rest of the day. From March to August, the net heat entering into the room per day is positive, thus more and more PCM melts and becomes liquid. The liquid portion of PCM increases from March to August, during September to February, there is a net heat rejection per day, thus the melted PCM becomes solid progressively, and at the end of February, almost all PCM has become solid. Thus there is melting cycle on daily basis and over the year. It takes care of all the external climatic variations and keeps the roof bottom surface temperature almost constant and closes to room air temperature. On yearly basis, about 56% reduction in heat transmission into the room is obtained with PCM roof when compared to the conventional weathering coarse laid roof.

Generalization of Vigenere Cipher

Yumnam Kirani Singh

A generalized way of Vigenere Cipher is proposed here. Here, instead of using a Vigenere square for encryption and decryption, any two reversible square matrices whose rows or columns are unique are used for encryption and decryption purpose. One matrix can be easily obtained from the other and hence any one of them can be used for encryption while the other can be derived from the other for decryption. This avoids the necessity of using two separate reversible matrices for encryption and decryption.  Also, a new algorithm for generation of key-stream with or without using a random symbol sequence is suggested. The key streams are generated from a small key word. The key streams are different for any slight difference of keywords either in length or content. Moreover, a key stream would be effectively random and as long as we please.

Performance improvement study of solar water heating system

P. Sivakumar, W. Christraj, M. Sridharan and N. Jayamalathi

Abstract:

Heating water for domestic purpose is a simple and effective way of utilizing solar energy. Initial cost of solar water heating system is high. But we get zero green energy cost. This paper discusses the improving of the performance of a flat plate solar energy collector by changing the design parameters of the number of riser tubes and the arrangement of riser tubes in zig-zag pattern from the existing flat plat collector system. Experiments were conducted using copper tube in header and riser with different dimensions. The performance shows that the efficiency is 59.09% when increasing the number of riser tubes and its 62.90% in the zig-zag arrangement (Z- Configuration) of the riser tube. Now-a-days this system produces higher efficiency than the existing conventional flat plate collector.

A factor model to explain the hydrochemistry and causes of fluoride enrichment in groundwater from the middle Voltaian sedimentary aquifers in the northern region, Ghana

Sandow Mark Yidana, Duke Ophori, Bruce Banoeng-Yakubo and Abdul Aliou Samed

Abstract:

Groundwater plays a pivotal role in the domestic water delivery system in the northern parts of Ghana. The resource has sometimes been rendered unsuitable for the use for which it is intended. In this study, a factor model was developed to determine the major hydrochemical processes that control the variations in the concentrations of fluoride and other ions in the groundwater delivered by the Middle Voltaian aquifers in Savelugu and surrounding areas in the northern region. This study finds that four major processes control the hydrochemistry of groundwater resources in the area: dissolution of soluble salts in the aquifers, the oxidation of organic carbon by nitrate, silicate mineral weathering, and the dissolution of sulfate minerals in the aquifers. It is the finding of this study that fluoride enrichment is related to the weathering of silicate minerals. A linear interpolation map, showing the distribution of fluoride concentrations in the groundwater system has been produced. Two major groundwater types have been distinguished in this study: fresh Na-K-HCO₃ groundwater types, and Na-Cl groundwater types. The Na-Cl water types are associated with areas of high influence of the saline sedimentary beds, where groundwater has extremely high salinity which are not suitable for most domestic purposes. Mineral stability diagrams suggest that the most stable silicate mineral phase is montmorillonite which indicates restricted groundwater flow owing to the limited interconnectivity of the fracture systems that control the hydrogeological properties of the aquifers in the area.

Distinguishing land use types using surface albedo and normalized difference vegetation index derived from the SEBAL model for the Atankwidi and Afram sub-catchments in Ghana

Tayari Salifu and Wilson Agyei Agyare

Abstract:

Distinguishing land use types is mostly done through field surveys which does not easily capture the spatial changes in the land use/cover types. In this study, the Surface Energy Balance Algorithm for Land (SEBAL) model was used to estimate surface albedo and NDVI, for different land use/cover types for two sub-catchments (i.e., Atankwidi and Afram) in the Volta Basin of Ghana. The mean coefficient of variation (CV) for individual land use/cover types compared to the mean CV for a given site was then used to distinguish among the land use/cover types. It was found that these parameters derived from the SEBAL model can be used to distinguish among different land use/cover types in the two sub-catchments. SEBAL estimates for surface albedo and NDVI across the different land use/cover types varied from 0.05 to 0.22 and -0.41 to 0.38, respectively. The range of CVs for surface albedo and NDVI, were 5-22% and 7-175%, respectively across the different land use/cover types for the two catchments. The results of this study demonstrate that SEBAL’s derived surface albedo and NDVI can be used to distinguish land use/cover types in catchments similar to those of the study areas with few ground measurements.

Compressive strength of concrete using lateritic sand and quarry dust as fine aggregate

Joseph O. Ukpata, Maurice E. Ephraim and Godwin A. Akeke

Abstract:

This paper is part of a study investigating the structural characteristics of concrete using various combinations of lateritic sand and quarry dust as complete replacement for conventional river sand fine aggregate. Samples of concrete (eg. cubes) were made using varying contents of laterite and quarry dust as fine aggregate. The quantity of laterite was varied from 0% to 100% against quarry dust at intervals of 25%. The samples were cured for specified periods and tested in the laboratory for compressive strength. Workability tests were earlier carried out to determine the optimum water/cement ratios for three different mixes, namely: 1:1:2, 1:1.5:3 and 1:2:4. It was found that 0.5 water/cement ratio produced higher compressive strengths for 1:1:2 mix, while 0.6 water/cement ratio exhibit better workability for 1:1.5:3 mix proportion. Specifically compressive strength ranged from 17-34.2 N/mm² for the mixes considered. These results compare favourably with those of conventional concrete. The concrete was found to be suitable for use as structural members for buildings and related structures, where laterite content did not exceed 50%.

Abstract:

A modified rectangular patch antenna design has been proposed in this paper, the bandwidth of this antenna is enhancement using the tapered slot with type of feeding (probe feed). This design is simulated with microwave office 2008 software package. This method is employed for analysis at the frequency band of (1 GHz- -- 3 GHz). When it was changed the location and dimensions of tapered slot. It gives a good VSWR less than (2), return losses (RL) less than (- 10 dB) and impedance bandwidth of the order of (13.1%) at the frequency band of (2.2921GHz- 2.6063) GHz of [2-3] GHz.

Abstract:

An experimental investigation has been conducted to study the mechanical as well as micro structural properties of Recycled aggregate concrete (RAC) exposed to elevated temperature. Fly ash (as replacement of cement) was added while making concrete. Recycled aggregates are mixed with natural aggregates also to prepare concrete. Cubes and cylinder test specimens were prepared and cured under water for 28 days. Test specimens were exposed to different levels of temperature (200oC, 400^oC, 600^oC, 800^oC, 1000^oC) for a period of 6 hours in the furnace. The reduction in compressive strength observed are in the ranges from 21% to as high as 61% when exposed to elevated temperature. Modulus of elasticity reduces appreciably also with the increase of exposure temperature. MIP (Mercury intrusion porosimetry) test was conducted to estimate the percentage of voids and also to appreciate the change of micro voids due to change of exposure temperature. Microscopic study was made to note the change of surface texture. Empirical formulae involving major parameters such as fly ash content, exposure temperature etc. have been developed to predict modulus of elasticity of Recycled aggregate concrete.

Radiation effects on MHD flow through porous media past an impulsively started vertical oscillating plate with variable mass diffusion

U.S. Rajput and Surendra Kumar

Abstract:

Radiation effects on MHD flow through porous media past an impulsively started vertical oscillating plate with variable mass diffusion is studied here. The fluid considered is gray, absorbing-emitting radiation but a non-scattering medium. The governing equations involved in the present analysis are solved by the Laplace-transform technique. The velocity, skin friction, Nusselt number and Sherwood number are studied for different parameters like radiation parameter, Schmidt number, Thermal Grashof number, mass Grashof number, phase angle and time.

Response of cooling towers to wind loads

Abstract:

This paper deals with the study of two cooling towers of 122 m and 200 m high above ground level. These cooling towers have been analysed for wind loads using ANSYS software by assuming fixity at the shell base. The wind loads on these cooling towers have been calculated in the form of pressures by using the circumferentially distributed design wind pressure coefficients as given in IS: 11504 - 1985 code [1] along with the design wind pressures at different levels as per IS:875 (Part 3) - 1987 code [2]. The analysis has been carried out using 8-noded shell element (SHELL 93) with 5 degrees of freedom per node. The results of the analysis include membrane forces, viz., meridional force (N_f) and hoop force (N_q), and bending moments, viz., meridional moment (M_f) and hoop moment (M_q). The vertical distribution of membrane forces and bending moments along 0^o and 70^o meridians and the circumferential distributions at base, throat and top levels have been studied for both the cooling towers. For circumferential distribution, non-dimensional values have been obtained by normalizing the membrane forces and bending moments using the reference values at 0^o meridian. Similarly, the reference values at the base have been used for vertical distribution. These non-dimensional curves for both the cooling towers have been compared in the present study for the feasibility of any generalisation.

Friction coefficient of rubber sliding against flooring materials

El-Sherbiny Y. M., Hasouna A. T. and Ali W. Y.

Abstract:

The friction coefficient of rubber sliding against different types of flooring materials of different surface roughness was investigated under different sliding conditions: dry, water, water/detergent dilution, oil, water/oil dilution. The flooring materials are parquet, polyvinyl chloride (PVC), epoxy, marble, cement and ceramic. Surface roughness variations do take place by continuous rubbing during the life time of the flooring. Based on the experiments, it was found out that at dry sliding, friction coefficient decreased with increasing surface roughness. Epoxy displayed relatively higher friction than parquet and PVC, while cement tiles gave the highest friction coefficient. Ceramic showed relatively lower friction values than marble and cement. In the presence of water on the sliding surface, friction coefficient slightly increased up to maximum then decreased with increasing surface roughness. Parquet displayed the highest friction coefficient followed by PVC and epoxy. At higher roughness marble tiles gave the highest friction. Ceramic showed the lowest friction among the tested floorings. Sliding of rubber against water/detergent wetted tiles caused drastic decrease of friction coefficient. Parquet displayed the highest friction values followed by cement and marble. PVC, epoxy and ceramic represented relatively lower friction values. At oil lubricated sliding of flooring materials, friction coefficient slightly increased up to maximum then decreased with increasing surface roughness of the flooring materials. Hard floorings such as marble and ceramic showed friction increase with increasing surface roughness. Parquet and cement tiles showed the relatively highest friction. Finally, sliding of rubber against water/oil dilution wetted floorings caused significant decrease in friction coefficient. Parquet and cement tiles still displayed the highest friction.

Broadband design and simulation of trapezoidal slot of microstrip antenna

Ali A. Dheyab Al-Sajee

Abstract:

A trapézoïdal slot  antenna is présented in this work, The design of RMSA is done for different dimensions and locations of single trapezoidal  slot that was  loaded on the rectangular patch antenna and the selection is based upon which diemension and location give a better performance of microstrip antenna, the  impedance, VSWR, radiation characteristics of this antenna are studied. Simulation  results indicate that overall BW is increased by (500 MHz) with the best dimensions (Ws=2.375mm, and Ls= 22.8877mm) and location of slot is (Fd=7.51775mm) upper the feed probe. This method is employed for analysis at the frequency band of 1 GHz- 3 GHz. There give a good VSWR less than (2), return losses (RL) less than (- 10 dB). This analyse is simulated applied wave research (AWR) package.