Time-dependent behavior of pile under lateral load using the bounding surface model

Qassun S. Mohammed Shafiqu and Maarib M. Ahmed Al-Sammaraey

Time-dependent behavior of pile embedded in saturated porous medium has been investigated in this study using the finite element method. This behavior occurs due to consolidation of the saturated medium and which was implemented through a fully coupled Biot formulation. The finite element analyses were carried out using the elasto-plastic bounding surface model for representing soil surrounding the pile. The model together with Biot consolidation were implemented and verified. The investigation of the time-dependent behavior of pile under lateral load was then carried out in five types of cohesive soils and the results showed that the elasto-plastic bounding surface model provide a realistic stress distribution within the soil mass around the pile. Also, it was observed that significant influence of time (i.e., consolidation process) on pile displacements will appeared. Finally, the study shows a significant influence of the critical state parameters λ and κ on the time-dependent behavior of pile under lateral load.

Investigation of emission reduction with selective catalytic reduction (SCR) in a D.I. diesel engine

B. Jothi Thirumal and E. James Gunasekaran

Emission control is one of the biggest challenges in today’s automobiles. The 3-way converter is expensive and cannot work under oxygen rich environment. The present investigation deals with the reduction of NO_x with selective catalyst reduction (SCR) in a 0.5 litres Kirloskar AV-1 Engine running under maximum load condition. In order to study the emissions reduction potential of this different catalyst has been investigated. For maximum engine load, the NO_x emission without SCR is maximum at 450 ppm, and it is reduced by 49% when catalyst zeolite and kaolin is used. With the catalyst magnesium and potassium the emission reduction is 38%. Catalyst magnesium and potassium with DOC the emission reduction is 31%. Similarly for maximum engine load, the Smoke emission without SCR is 18 HSU, and it was reduced by 33% when catalyst zeolite and kaolin is used. Likewise for catalyst zeolite and kaolin with DOC the emission reduces to 28% and for catalyst magnesium and potassium the emission is 17%. For maximum engine load the CO emission is 0.02 (% by volume.) without SCR and it is being reduced by 0.01 (% by volume) when SCR along with different catalysts are used.

Smoothed doppler profile in MST radar data- The modified cepstrum approach

The concept of cepstrum thresholding (CT) is applied to estimate smoothed nonparametric spectrum. The CT method is applied to Mesosphere, Stratosphere and Troposphere (MST) radar data for spectral cleaning. This method is not superior as compared with the conventional Periodogram method. So, to enhance the spectral visibility in Doppler Profile (DP), the CT technique is modified. The modified cepstrum (MC) is developed and implemented, to validate, it is applied to radar data. An adaptive spectral moment’s estimation technique is utilized for analyzing the Doppler spectra of the MST radar signals. From the Doppler frequency components, the radial velocities in the direction of the zonal (U), meridional (V), and vertical (W) are estimated. In turn, the wind velocity is estimated from U and V components. The proposed method works well even at higher altitudes and results are compared with the traditional methods such as Peak detection technique and the matched filter.

Comparative study on various bipolar PWM strategies for three phase five level cascaded inverter

Balamurugan. C. R., Natarajan. S. P. and Padmathilagam V.

This paper presents the different types of bipolar Pulse Width Modulation (PWM) strategies for the chosen Cascaded Multi Level Inverter (CMLI). The main purpose of multilevel inverter is to produce approximate sinusoidal wave voltage output using the method of superimposing multiple voltage steps. Due to their ability to synthesize a higher output voltage than the voltage rating of each switching device without a transformer, multilevel inverters are suitable topologies due to low Total Harmonic Distortion (THD) and low voltage stress (dv/dt) which minimize Electro Magnetic Interference (EMI) and also switching losses compared to traditional inverters. In this paper, a cascaded multilevel inverter is controlled with Sinusoidal PWM (SPWM) technique, Third Harmonic Injection (THI) PWM technique and Sixty degree PWM technique with Sub harmonic PWM (SHPWM), Phase Shift (PS), Variable Frequency (VF), Carrier Overlapping (CO), Phase Opposition and Disposition (POD) and Alternative Phase Opposition and Disposition (APOD) modulation strategies. The variation of THD in the output voltage is observed for various modulation indices. Simulations are performed using MATLAB-SIMULINK. It is observed that SHPWM provides output with relatively low distortion for THIPWM and 60 degree PWM references where as PSPWM performs better for sine reference. It is also seen that COPWM is found to perform better since it provides relatively higher fundamental RMS output voltage for all references.

Performance study of DSTATCOM with PI controlled SVPWM and hysteresis current controller for power factor improvement

K. Murugesan, D. Sai Praveen, Tathagata Mitra and Ranganath Muthu

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A Distribution STATCOM (DSTATCOM) is a current controlled Voltage Source Converter (VSC) used for reactive power compensation, when connected to the power system. The DSTATCOM using PI controlled Space Vector Pulse Width Modulation (SVPWM) technique has high peak overshoot and large settling time. SVPWM technique requires Phase Locked Loop (PLL) for measuring the varying frequency, required for Park’s transformation, for control. This paper presents a DSTATCOM for reactive power compensation using space vector based Hysteresis Current Controller (HCC) and compares its performance with that of PI controlled SVPWM method. The HCC technique is robust and has faster transient performance compared to SVPWM control technique. In addition, this technique does not require PLL for measuring frequency, has reduced switching losses, and is easy to implement. The performance of DSTATCOM with HCC is studied in MATLAB/SIMULINK environment.

Recycling demolition waste sandcrete blocks as aggregate in concrete

Akaninyene A. Umoh

Abstract:

Construction and Demolition waste generated by the construction industry and which posed an environmental challenge can only be minimized by the reuse and recycling of the waste it generates. Therefore, this study seeks to utilize sandcrete blocks from demolition waste as an alternative material to fine aggregate in concrete. A concrete with compressive strength of 30N/mm² at 28 days hydration period was designed for normal mixture as the control. The fine aggregate was replaced with crushed waste sandcrete block (CWSB) in various percentages in the steps of 10 starting from 10% to a maximum of 100%, while 0% represents the control. The properties of the concrete were evaluated at 7, 14 and 28 days curing periods. Results showed that replacing 50% of CWSB aggregate after 28 days curing attained the designed compressive strength as the conventional concrete (i.e., the control). Thus it is concluded that CWSB can be used as a supplementary aggregate material in concrete.

Identification of optimal polymeric blend (SR-EPDM) using soft computing optimization techniques-PSO and GA

R. Deepalaxmi, M. Balaji and V. Rajini

This paper presents the application of the soft computing optimization techniques such as Particle swarm Optimization (PSO) and Genetic algorithm (GA) to identify the Optimal Blend of Silicone Rubber (SR) and Ethylene Propylene Diene Monomer (EPDM). The behavior of the polymeric materials such as SR and EPDM are found to be un-satisfactory, due to their inherent shortcomings as the homo polymer. To overcome those limitations and also to fully avail the superior properties of both the materials, blending of SR-EPDM is done. As per ASTM and IEC standards the blends are tested, in order to find their mechanical properties like tensile strength (TS) and elongation at break (EB) and also the electrical properties like volume resistivity (VRY) and surface resistivity (SRY), arc resistance (AR) and comparative tracking index (CT). It is really hard to choose a optimal blend (OB), among the large number of electro-mechanical parameters. In order to identify the OB with superior performance indices compared to that of the constituent polymers, optimization techniques are used. The determination of the optimal blend of SR-EPDM is formulated as a multi-objective optimization problem with the objective of maximizing the electrical and mechanical properties. Based on the weightage assigned for various electrical and mechanical parameters, the Optimal Blend Problem (OBP) can provide a improved performance as desired. Particle swarm optimization (PSO), part of the swarm intelligence family, is known to effectively solve large-scale nonlinear optimization problems. In this paper, the PSO is used to find the optimal blend ratio (OBR) for cable applications. To high-light the superiority of PSO and also to validate the results, a comparison has been made with Genetic Algorithm (GA) Technique.

Application of direct variational method in the analysis of isotropic thin rectangular plates

Aginam C. H., Chidolue C. A. and Ezeagu C. A.

Abstract:

The popular methods of analysis of thin rectangular plates have been numerical and classical procedures. These methods, especially the classical method have always been tedious and rigorous. In this study, the mathematical model, that is based on direct variational procedures and potential energy principle, is developed and successfully applied to: (i) Thin rectangular Plates with two opposite edges clamped and other opposite edges simply supported and (ii) Thin rectangular plates with one edge clamped and the three other sides simply supported. The coordinate functions, which must satisfy the geometric and natural boundary conditions, are carefully constructed and applied into classical plate equation. The plate equation is thus integrated and the integrand minimized to obtain the unknown coefficients which when substituted back in deformation equation of mid-surface of plate gives the deformation surface of plate in analytical form. This enables the evaluation of deflections and bending moments at any arbitrary point on the plates unlike the numerical methods which only give these results at nodal points. The results obtained from this study have excellent comparison with those of numerical and classical solutions obtained from literature. The study also clearly shows that direct variational method circumvents the tedious and rigorous procedures involved in the classical and numerical methods.

Optimization of compressive strength in Zirconia nanoclusters of the Bis-GMA and TEGDMA based dental composites

Umesh Vishnu Hambire and Vipin Kumar Tripathi

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The aim of this work is to present an analysis of the composites and furnish dentists with a basis that can provide criteria for choosing one or another to suit their therapeutic requirements. Mastication is a dynamic process and tooth is an important component of it. Restoration of lost tooth structure is a challenge to the dentist as well as scientists testing the restorative materials. One of the most commonly used restorative materials is composite resin. The mechanical properties of composite resins are mainly due to its filler content. Dental composites are using silica, quartz and glass as filler for long time. Zirconia is the latest addition as filler. Zirconia is super hard because of the peculiar arrangements of atoms. Mastication is a dynamic situation in which many forces are acting in all possible direction, the most important being the compressive force. We wish to study the contribution of Zirconia as filler in the mechanical properties of the dental composite. Our aim is to optimise the compressive strength in Zirconia nanoclusters of the Bis-GMA and TEGDMA based dental composites. The aim of this paper is to evaluate the important role of Zirconia as filler in the Compressive strength of Dental Composite. Contemporary dental composites are using either one or two fillers individually or in combination. Attempt is made to use Zirconia, glass and silica conglomerate. The optimum composition of hybrid fillers and the optimum compressive strength is obtained.

Abstract:

This paper shows two approaches of refrigerant comparison for retrofit replacement. One is the screening based on refrigerant thermo-physical properties and based on the cycle performance analysis, another method is the full simulation. The impact of component sizes on the refrigerant temperatures and performance is included in the full simulation while it is ignored in the former analysis. The methods are exemplified by comparing some common refrigerants, e.g. R32, R410A, R125, R1270, R22, R407C, R290, R134a, R600a and R600.

K. Kanchana and V. Rajini

Abstract:

This paper describes the analysis of the over-voltage phenomena at the motor terminal of an inverter fed induction motor. The high frequency model for a three phase cable and induction motor is simulated using Simulink and analyzed for the over-voltage for different cable length. The results indicate that the over voltage is a function of cable length and it also depends on gauge of the cable.

Modeling of grid connected hybrid wind/PV generation system using MATLAB

Abstract:

This paper presents the modeling of grid connected hybrid wind-solar photovoltaic (PV) system. The proposed system consists of wind generator, wind-side converter, solar PV array, dc-dc converter, and grid interface inverter. Maximum Power Point Tracking (MPPT) is important in solar PV system, because they maximize the output power from the PV system so that effective PV array utilization. The power extracted from hybrid wind-solar power system is transferred to the grid interface inverter by keeping common dc voltage constant. Sinusoidal Pulse Width Modulation (SPWM) technique is used for generating pulses for inverter. The simulation study is carried out using MATLAB and results are presented.

Abstract:

Data clustering is one of the common approaches used to carry out statistical data analysis, which is used in several fields, together with machine learning, data mining, customer requirement, trend investigation, pattern identification and image analysis. Even though many clustering approaches have been available, but most of them manage only the clustering of numerical data. On the other hand, the problem of clustering mixed data is more complicated and difficult as mixed data have nominal attributes. A large number of these algorithms deals with only on numeric data, a small number of algorithms take care of nominal data, and only a very least amount of algorithms can handle both numeric and nominal values. In order to provide an efficient mixed data clustering, there is a significant need for several approaches to handle mixed data clustering. The existing mixed data clustering techniques takes more time for clustering the usage of SOM has the inability to capture the inherent hierarchical structure of data. To overcome this, an integrated GHSOM-MLP with Modified LM Algorithm is proposed in this paper. The experimentation for the proposed technique is carried with the help of UCI Adult Data Set to compare the proposed approach with GHSOM, in terms of number of resultant clusters and mean square error.

Diagnosis and characterization of effects of broken bars in three phase squirrel cage induction motor using finite element method

Nagarajan S. and RamaReddy S.

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Large investments are aimed at minimizing power needed for propulsion i.e., new downsized engines with new aerodynamic devices for drag reduction. For passenger vehicles the aerodynamic drag force is the dominating resistance force at higher velocity. The vehicle body is often optimized for reducing the drag resistance. Vortex generators belong to the category boundary layer manipulators. Their function is to reenergize an adverse pressure gradient boundary layer that is about to separate by transporting high momentum fluid from the outer part of the boundary layer down to the low momentum zone closer to the wall. In this experimental investigation the variation of pressure coefficient, dynamic pressure, coefficient of lift and drag with and without vortex generators (VG) on the roof of a utility vehicle have been studied at varying yaw angles of VG. The yaw angles used are 10˚, 15˚ and 20˚. To measure the effect of altering the vehicle body, wind tunnel tests have been performed with 1:15 scaled model of the utility vehicle with velocities of 2.42, 3.7, 5.42 and 7.14m/s. The experiments showed that a great improvement of the aerodynamic drag force reduction can be achieved with vortex generator.

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Machine crushed animal bones as partial replacement of coarse aggregates in lightweight concrete

Javed Ahmad Bhat, Reyaz Ahmad Qasab and A. R. Dar

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