Open Access Original Research Article

Development of the Model for Simulation of Transient Processes in Cables and Power Lines

U. Jakšić, N. Marković, J. Živanić, N. Milenković

Current Journal of Applied Science and Technology, Page 1-10
DOI: 10.9734/CJAST/2017/39169

Aims: The paper presents a model of the power line and the equivalent scheme for the simulation of the transient processes. Many constructions of conductive lines are such that mutual parameters (inductance, capacitance) are the same for any pair of phases, and the phase parameters themselves are approximately the same for all three phases. Therefore, the approximation of three-phase conductors with symmetric single-phase conductors is justified. A special way in which the power lines are considered is a method called a sequence model of three-phase line.

Methodology: Techniques used in this paper are based on analytic methods and the formation of algorithms. Modeling and simulation are processes that are necessary for testing faults in measuring transformers in relay protection (current/voltage) when they are very remote and electrically connected by cables. The first step in problem-solving was to define the theoretical model for estimation of the impact of variable parameters on the transmission of electric energy. Further step represented in the paper is simulation of transient processes on different lengths of the power lines when modeling lines and cables, one starts from the fact that parameters differ in certain parts, in lengths, i.e. that the parameters are variable in length, which results in change of longitudinal parameters of basic quadripoles in equivalent schemes.

Conclusion: The specificity of the model is that the initial conditions matrix is determined depending on the condition at the beginning of the line and load in equivalent scheme and arises from the idle time or short circuit at the output of the quadripoles. The solution for transient state with the application of quadripole in the equivalent scheme is obtained by matrix procedure using equivalent schemes and by simulation method in the MATLAB program.

Open Access Original Research Article

Optimization of the Rehabilitation of Concrete Buildings Based on Their Dynamic Properties

Jaime Horta Rangel, Ivan Calderon, Luz Perez Rea, Teresa Lopez Lara, Juan Hernandez Zaragoza, Eduardo Rojas Gonzalez

Current Journal of Applied Science and Technology, Page 1-13
DOI: 10.9734/CJAST/2017/39179

The present work describes the development of an optimization model for the rehabilitation process of concrete buildings damaged mainly by the effects of an earthquake. Currently, the process is carried out according to the current standards and the damage assessment is based largely on visual damage, which can obviate internal damage to the elements of the structure which cannot be detected at a glance and which will affect its behavior in the future. By means of a non-linear optimization process, the optimization of the modal analysis of concrete buildings has been carried out by means of steel or concrete jacketing in order to reduce the increase in weight generated by these new elements. When analyzing the results it can be observed how increasing the quantity of elements to be repaired increases the complexity to obtain a combination of sections that while keeping the increase in weight to a minimum does not negatively affect its fundamental frequency.

Open Access Original Research Article

Variance Estimation Using Linear Combination of Standard Deviation and Deciles

M. A. Bhat, S. Maqbool, Ab. Rauf, S. A. Saraf, M. A. Malik

Current Journal of Applied Science and Technology, Page 1-6
DOI: 10.9734/CJAST/2017/37323

In this present study, we have introduced a new type of ratio estimators for the estimation of finite population variance using standard deviation and deciles as auxiliary variables to improve the efficiency of proposed estimators. A comparison between suggested estimators and existing estimators has been made through a numerical illustration to prove the efficiency of proposed estimators over existing estimators. The expression for bias and mean square error has been derived up to the first order of approximation. The improvement of proposed estimators over existing estimators shown is clearly based on the lesser mean square error of proposed estimators.

Open Access Original Research Article

Assessing the Potential Ecological Risks of a 12-Year Old Reclaimed Post-Mined Site for Agricultural Land-Use

Nat Owusu-Prempeh, Daniel E. K. A. Siaw, Osei Owusu Antobre

Current Journal of Applied Science and Technology, Page 1-14
DOI: 10.9734/CJAST/2017/39456

Mining is a crucial component of local and global economies, but it inevitably leads to substantial environmental disturbance. Reclamation ensures that a disturbed land is rehabilitated for a specified end land-use. The study examined the nutrient levels and risks status of a twelve-year old reclaimed site to ascertain its suitability for agricultural land-use. Twenty subplots of dimensions of 10m x 10m were laid within the reclaimed plots whereas 10 subplots where laid within adjacent undisturbed cocoa farm as control plots. Generally, the concentrations of all heavy metals and exchangeable cations of the reclaimed site’s soil were significantly higher than the control plots and so were their respective cumulative potential ecological risk (PERI). The level of heavy metals contamination followed the order: Fe > As > Ni > Cu > Zn > Pb. Among the observed cations, only Magnesium (Mg) had the highest correlation with 60% of the variables of the study. The geostatistical analysis obtained by interpolation of risk values of the respective sites and classification into the risk categories revealed that the reclaimed area poses a “considerable ecological risk” (approximately 59% of the study area) due to the heavy metals’ contamination. Thus, whiles the exchangeable cations concentrations favour agriculture, the potential ecological risks of the reclaimed site due to heavy metals’ contamination made it unsuitable for agricultural land-use. The study has provided empirical evidence that would guide policy on decommissioning and release of post-mined reclaimed lands to communities for a specified end land-use in support of their livelihoods.

Open Access Original Research Article

Microbial and Chemical Indicators of Rhizospheric Soils of Apple (Malus domestica Borkh.) Variety Delicious in Himalayan Kashmir

Malik Sajad Ahmad, M. Y. Zargar, Shaheena Kousar, Sartaj Ahmad Wani, F. Akhter

Current Journal of Applied Science and Technology, Page 1-7
DOI: 10.9734/CJAST/2017/36852

With the introduction of high yielding varieties and hybrids during green revolution, the soils are getting depleted in nutrient reserves at a faster rate. As a consequence, nutrient deficiencies are becoming one of the major constraints in crop production, especially in coarse-textured soils. Microorganisms present in the rhizospheric soils supply principal elements to the plant and also promote other activities in the soil which improve its structure, aeration, and water holding capacity, which in turn improve the soil capabilities to respond to inputs. This investigation deals with the evaluation of thirty composite soil samples collected from different apple orchards of Shopian district of Kashmir valley, is popular for its cultivation, and analyzed for soil characteristics like organic carbon content, total available N, P, K, S; EC, pH, total viable bacterial, fungal and actinomycetes count as chemical and microbial indicators of rhizospheric soil health of apple orchards in Himalayan Kashmir. It was observed that the soil characteristics were significantly correlated at 95% to 99%confidence interval except available phosphorus and sulphur with each other.

Open Access Original Research Article

Research on Preparation of Flocculants for Sugar Factory Wastewater Treatment

Chang-Yi Jin, Zu-Yu Liu

Current Journal of Applied Science and Technology, Page 1-5
DOI: 10.9734/CJAST/2017/38533

Polyacrylamide, formaldehyde and carbamide or guanidine carbonate were used as raw materials, cationic polyacrylamide flocculants were synthesized with Mannich reaction, effects of technical conditions on rate of turbidity removal were investigated, and synthesis technics was optimized. Experimental results showed that the flocculation properties of the products prepared with Mannich were better than ones of blank experiments (polyacrylamide). In the same dosage of flocculants, consumption of polyacrylamide in the products was smaller than (or equal to) 1/10 of polyacrylamide (blank experiments), reducing flocculation cost greatly. In the real wastewater treatment of sugar factories with the prepared products under optimum conditions, the turbidity removal rates was approaching to 90% or greater than 90% showing flocculation effectiveness was better. In addition, the wastewater of sugar factories was treated with prepared products and the removal of COD was 10~30%, which showed that using flocculating agents could reach the purposes of wastewater pretreatment.

Open Access Original Research Article

Development of Three-Zone Transitional Model for Reciprocating Internal Combustion Engine Analysis Using Gasoline

A. A. Dare, O. S. Ismail, O. B. Olatunde

Current Journal of Applied Science and Technology, Page 1-11
DOI: 10.9734/CJAST/2017/39007

A three-zone model based on the first law of thermodynamics has been developed for analysis of combustion in an Internal Combustion Engine. The three zones included an unburned zone, burned zone and transitory zone which is a mixture of burned and unburned gases. The model was used to analyse an SI engine operating with gasoline fuel. An arbitrary constant for each of fractional burnt zone (CC2) and fractional unburned zone (CC1) leakages was varied using 0.0005, 0.00025, 0.001, 0.002, 0.005, 0.1 and 0.5.  The engine operating conditions were set at a speed of 2000 rpm, -35bTDC ignition time and burn duration at 600. The obtained indicated mean effective pressure (IMEP), thermal efficiency (η), cylinder pressure and emission characteristics from the developed model and those of two zone analysis were both compared with literature values. Most favourable results were observed at CC1 and CC2 values of 0.00025 and 0.005 respectively. We can conclude the 3zone model predicts better the IMEP, η, and peak cylinder pressure. However, no significant change was observed in values of emission characteristics of the 2zone and 3zone models. It is worthy of note that the number of zones affects engine performance evaluation and the higher the computational zone the better the engine prediction.