Proper Design Procedure Research Articles

Analysis and Performance Validation of CRONE Controllers for Speed Control of a DC Motor

In recent decades controllers play a major role for an efficient control and reliable operation of an industrial process. Hence in this paper, a special kind of Commande Robuste d’Ordre Non Entier (CRONE) controller is designed for controlling the speed of DC Motor (DCM). The proper design procedure of two generations CRONE control strategies named as First-Generation CRONE (FGC) and Second-Generation CRONE (SGC) controllers are implemented through the transfer function of armature-controlled DCM. Simulations are performed on MATLAB software in order to investigate the servo responses of two designed CRONE controllers, besides the results are presented in terms of settling time(ts), rise time(tr), Integral Square Error (ISE) and Integral Absolute Error (IAE). In addition, the relay PI controller is designed and the simulation results are presented for comparison purpose. It is evident from the comparing results that the SGC controller is superior for effective process control.

Grid Harmonics Suppression for Three Phase Dual-Frequency Grid-Connected Inverter Based on Feedforward Compensation

Using a low pulse ratio, the electromagnetic interference and switching loss of an inverter can be effectively reduced, particularly in high-power applications. However, due to variations in grid impedance, it is a challenging task to achieve stable operation of an LCL-type grid-connected inverter (GCI) using the active damping method with low pulse ratio. Thus, a novel three-phase dual-frequency GCI is presented to ensure the symmetry of the output power and the stable operation of the system address stability issues. The proposed inverter topology in this article is composed of two inverters in parallel, which are, respectively, a power inverter unit (PIU) and an auxiliary harmonic elimination unit (AHEU). To reduce the switching loss and improve the inverter efficiency, the switching frequency of the PIU is relatively low, injecting current into the grid. Moreover, the feedforward compensation method is used in AHEU. AHEU operates at high switching frequency to generate a current component that is symmetrical with the ripple com-ponent, improving the power quality, without extracting the current harmonic as the current reference. The operating principle of feedforward compensation is explained, and a proper parameter design procedure is presented in this paper. Since L filters are used for the proposed inverter, the system can operate stably where the ratio of switching frequency to fundamental frequency is low. A 10 kW laboratory prototype was built. The experimental results showed that the grid current ripple could be effectively eliminated and the THD of the grid current was 3.01%. The proposed inverter has good stability in a weak grid, and the efficiency of the proposed inverter is 95.98% at rated current, which is 0.81% higher than the traditional GCI, effectively increasing the efficiency of the system.

Analysis and Design of Two-Switch Enhanced Gain SEPIC Converter

A two-switch, enhanced gain single-ended primary inductor converter (SEPIC) is proposed with key benefits of enhanced voltage gain, reduced voltage stress and better efficiency, as it is suitable for low voltage green energy applications. Further, reduced voltage stress between the intermediate capacitors is a notable attribute of this converter. The converter components are designed with proper design procedure and a steady-state analysis is performed to study its operation. A small-signal analysis of the proposed converter is also presented to examine the pole-zero positions. Also, this paper includes the performance comparison with other similar converters. Simulation and experimental results of the proposed converter with a rating of 100 W/50 kHz and input and output voltages of 20 V and 200 V, respectively are provided. Efficiency as well as power loss distribution are also investigated in this study.

A Study on the indoor air quality (IAQ) at primary school in Industrial Area: A case study to Sekolah Kebangsaan Pasir Gudang 3(SKPG3)

Existing research has shown that numerous air contaminants are present in classrooms, sometimes in high concentrations, which may have an impact on children’s health and academic performance. In order to create a safe, healthy, productive, and comfortable atmosphere for students, instructors, and other school personnel, schools must have good indoor air quality. This study has assessed the current IAQ’s level at selected school in one of the industrial areas in Johor Bahru, which is Pasir Gudang. To measure the quality of the indoor air parameters, three chemical substances which are Formaldehyde (HCHO), Total Volatile Organic Compound (TVOC) and Particulate Matter (PM) in the classroom were assessed. Besides that, this study also analyzed the temperature and relative humidity of the classroom surrounding. Furthermore, the students’ insight on the impact of IAQ parameters towards their class performances were also explored using questionnaire survey. It was found that physical parameters of the classroom were in good state, but the relative humidity percentage range was too high. Meanwhile, on the chemical contaminants, the measurement shows that the concentration of PM, HCHO and TVOC for the classroom are still in the permissible exposure range. In the end, some suggestions have been made to provide good indoor quality in the classroom by emphasizing proper design, construction, and ongoing maintenance procedures.

On Hierarchical Applications of Finite Element Methods and Classical Applied Mechanics Approaches for Complex Structures

In this paper, hierarchical studies based on both analytical and computational approaches have been employed to validate and improve current structural designs of mud holding tanks for hydraulic fracturing in petroleum industries. Through detailed comparisons at different levels of approximations for both real world complex structural design problem and a simplified stiffened plate with extreme geometrical aspect ratios, proper design procedures have been reiterated and validated. It is highly recommended that low-dimensional structures with emphasis on classical mechanics principles should be considered before full-fledged three-dimensional computational analyses. Both Castigliano’s Theorems and Galerkin methods are utilized along with simulation packages such as ADINA and Solidworks. The hierarchical approximation procedures reemphasize important subjects such as planes and shells, strength of materials, structural mechanics, asymptotic and perturbation analysis no longer required in some engineering programs, yet often necessary for the study of complex three-dimensional structural systems.

Analysis and Design of a Multi-Resonant Circuit for Applications of Wireless Capacitive Power Transmission

Capacitive technology for wireless power transmission has been shown to be a good option for charging the batteries of electric vehicles. It offers better coupling between the transmitter and the receiver than inductive power transmission. On the other hand, it has some disadvantages; for example, it is very sensitive to the distance between plates. Several ideas have recently been proposed to overcome this disadvantage. However, a proper analysis methodology is still lacking, as is a proper design procedure for the circuits used in capacitive transmission. In this paper, an analysis and design methodology is presented for applying the Z-tank resonant circuit to capacitive power transmission, and the theoretical design methodology is based on normalized equations with respect to the operating resonance frequency. The analysis methodology and design procedure result in a circuit where the resonance frequency remains constant despite changes in the distance between the capacitive plates. The simulation results validate the proposal; to ensure robust, realistic simulation results, parasitic elements were considered in all reactive components, and robust models were built for the switching elements, such as MOSFETs and diodes. The results show that the multi-resonant characteristic of the circuit achieves maximum energy transfer and high efficiency.

Experiment-based out-of-plane resistance of strong masonry infills for codified applications

In the last two decades, the typology of unreinforced masonry infills to be adopted in newly designed RC structures has been subjected to significant changes, passing from the use of slender/weak masonry panels with one or two layers, to stronger single-whyte walls. These modifications have allowed to reduce the construction time and to improve the thermal and acoustic performance. However, the adoption of a more robust masonry solution can significantly affect the response of infilled structures as respect to slender/weak typologies, but the current standards do not provide proper design procedures for the in-plane and out-of-plane verification of such masonry infills. In order to fill some of these gaps, this paper presents the experimental results of two masonry infills made of modern strong masonry tested only in the out-of-plane direction, without any previous in-plane load. The tests have permitted to apply and analyze the existing formulations in the codes and literature for the computation of the out-of-plane resistance and the fundamental period. Moreover, some new formulations have been proposed to better estimate these values according to the experimental evidence. In the proposed equations, dimensionless parameters have been introduced to include some important physical aspects, such as the bidirectional response of the masonry infill, the second order effects, the deformability of the frame and the occurrence of local mechanisms such as the sliding at the frame/infill interface.

22nm FINFET Based High Gain Wide Band Differential Amplifier

Differential Amplifier is a primary building block of analog and mixed signal circuit for pre-processing and signal conditioning of analog signal. FINFET devices with high-k gate oxide at 22nm technology are predominantly used for high speed and low power complex VLSI circuits. FINFET based differential amplifiers are widely used in ADC’s and signal Processing applications due to their advantages in terms of power dissipation. Analog front end of complex VLSI circuits need to offer high gain, higher stability and low noise figure. Designing of FINFET based VLSI sub-circuits requires proper design procedure that can provide designers flexibility in controlling the circuit performances. In this paper, differential amplifier is designed using model parameters of high-k FINFET in 22nm technology. The conventional procedures for designing MOSFET based differential amplifier are modified for designing FINFET based differential amplifier. Schematic capture is carried out in Cadence environment and simulations are obtained considering 22nm FINFET PDK. The performance metrics are evaluated and optimized considering multiple iterations. The designed differential amplifier has slew rate of 6V/µSec and settling time of 0.9 µSec which is a desired metric for ADCs. Power Supply Rejection Ratio (PSRR) is 83 dB and dynamic range is 1.6754 V. Open loop DC gain of DA is achieved to be 103 dB with phase margin of 630 that demonstrates the advantages of DA designed in this work suitable for analog front end

Strength studies on Geopolymer Concrete produced by Recycled Coarse Aggregate and Quarry Stone Dust as Fine Aggregate

Geopolymer concrete is one of the trending techniques adopted to replace the conventional binder by any alumino-silicate material like fly ash or GGBFS. Approximately Geoploymer concrete are as productive as conventional concrete. But the key pro of Geopolymer concrete utility is to recycle concrete waste and demolition waste are transformed into coarse aggregate, which reflects in the environment and economic benefits. The natural fine aggregate (NFA) is replaced by the residue quarry fines obtained from the crushed quarry rock often termed Quarry dust or Quarry stone dust (QSD) by proportions 0%, 20%, 40%, 60%, 80%, and 100%. In this research study, fly ash is utilized as the binding material activated by the di-solution of NaOH and Na2SiO3 collectively to initiate a chemical reaction to attain productive strength. From the overview of previous papers literature, the geopolymer concrete is not having any proper mix design procedures, Therefore the trial and error method adopted. This research is conducted to study over results of the practical approach on geopolymer concrete composed with 40% of recycled coarse aggregate (RCA) in place of Natural coarse aggregate and varying different percentages of QSD in the place of Natural fine aggregate.

Influence of boundary conditions on three-dimensional vibration characteristics of thick rectangular plates.

Vibration analysis of the classical elastic structures is not only essential for the study of vibration reduction by predicting the dynamic behavior, but also important to ensure a reliable, safe, and lasting structural performance through the proper design procedure. In this paper, the influence of boundary conditions on the free and forced three-dimensional vibration analysis of thick rectangular plates has been performed using the improved Fourier series method. For the elastically restrained thick rectangular plate, the three-dimensional improved Fourier series displacement forms are used to model the vibration field. The energy formula is employed to describe the three-dimensional dynamics of the plate. All the unknown Fourier series coefficients are then solved by the Rayleigh-Ritz method. In order to validate the proposed model, several numerical examples are provided and compared against the results from the literature and Finite Element Analysis (FEA). In addition, the effects of the boundary restraining spring stiffness and the thickness ratios of thick rectangular plates are analyzed under elastically restrained boundary conditions to develop an in-depth understanding of the three-dimensional vibration characteristics of thick rectangular plates.

High Efficient Solar Integrated an Isolated Dc-Dc Full-Bridge Converter for Electric Vehicle Battery Charging Application

In this paper, the power from a solar PV panel 20VDC, 12.5ADC is used for charging an electric vehicle battery (12V, 7Ah) with the help of an isolated dc-dc converter in an efficient manner. The power rating maintained in the system is around (200-250) W. The parasitic circuit analysis is carried out theoretically. The zero voltage transition (ZVT) technique is implemented at the inverter stage and an isolation transformer (1:1) is used for source-load isolation purposes. In order to achieve ZVT, a proper design procedure is followed and a pulse triggering technique is carried out at the switching element. The designed values of the parasitic elements are used in the Simulink tool. The open loop and closed loop system of the proposed converter are simulated in MATLAB Simulink package. In the open loop system, an irradiation analysis carried out similarly closed loop has reference voltage variation analysis in order to verify the system stability at the various operating condition. The problem of transients in open loop output is rectified in the closed loop operation. The MPP and PI control technique is initiated in the closed loop system for better performance. The MPP technique used is incremental conductance method for tracking maximum power from the PV array.

Mechanical Properties and Mix Design of Geopolymer concrete – A review

Geo-polymer concrete (GPC) is a most viable solution to cement as the raw materials depleting down the years and, many countries have started imposing carbon taxes. After a review for the literature reveals that there is no proper mix design procedure developed yet. GPC has better mechanical properties when compared to normal concrete. Curing conditions, setting times, workability, alkaline solution to binder ratios, molarity of alkaline solution, Na2SiO3/NaOH and SiO2/Al2O3 ratios play an important role to develop GPC. This paper presents an overview of Geopolymarization process, mechanical properties and mix design of GPC. Proper mix design of geopolymer concrete can produce desired mechanical properties for ambient curing condition. And geopolymer concrete can consider as eco-friendly construction material. This paper deals with study of advancement in mix design and mechanical properties of geopolymer concrete.

A standard formulation for the installation of suction caissons in sand

Suction assisted installation of caisson foundations in sand relies on the developed seepage around the caisson wall. Seepage is known to produce soil loosening inside the caisson cavity and an overall reduction in soil resistance to caisson penetration. On the other hand, suction must be controlled so that no excessive piping is induced within the sand volume trapped inside the caisson cavity. When it extends over the full embedded length of the caisson wall, piping may lead to the formation of piping channels, which may compromise the established seal between caisson and soil and ultimately cause the installation process to stop. A safe installation process requires a proper design procedure to ensure that a safe suction can be predicted prior to installation. The present paper provides a framework where analytical expressions are obtained for the required suction magnitude, and for the critical suction that causes piping to initiate at the caisson tip. These analytical expressions are derived for a normalized caisson geometry, based on compiled results obtained from finite element analysis of seepage around a caisson wall, at various installation depths. The developed analytical formulation applies independently of caisson dimensions such as diameter, height and wall thickness. Critical suction for piping condition is also obtained under analytical form as a function of normalized penetration depth. The developed formulation can also be easily incorporated into design procedures or used in design codes without a need for a preliminary seepage analysis to be undertaken. The proposed suction predictions for the whole process of caisson installation in sand are validated against field trials reported in the literature.

Design and analysis of PM motor with semi-circle stator design using 2D-finite element analysis

<p>This paper presents a basic approach to reduce an overall weight of selected PM motor. The approach is not based on normal sizing step by keeping the overall design in symmetry dimension, but by introducing semi-circle stator design. The investigation takes 12-slot/10-pole motor as a subject due to it symmetric winding disposition. Two designs are included, both having identical semi-circle stator but different in rotor configuration. Design 1 has a standard rotor design that equipped with 10-pole while Design 2 has a semi-circle rotor design following the stator design. This inherently result an even number of pole i.e. 5. From the investigation using 2D-Finite Element Analysis, an overall weight in PM motor can be theoretically reduced by having asymmetric design dimension. However, motor torque performance would deteriorate and unwanted noise may exist due to high cogging torque and high output torque ripple. A proper design procedure that includes parameter optimization and intelligent switching for optimum current excitation is required to restore the desired torque.</p>

Performance-based Seismic Design of 9-Story Engineered Wood Office Building

One of engineered woods, glued laminated timber (GLT), can provide a constant level of performance and desired strength even if the quality of wood is low. Due to this fact, there is a growing interest in GLT using domestic species and related research has been carried out continuously. In addition, GLT is popularly being applied to the long-span or high-rise structures overseas. However, KBC 2016 does not allow the engineered woods to be used for middle and high-rise buildings by limiting height. Therefore, a proper design procedure and rationale should be clearly presented by the help of performance-based seismic design. With this background, the goal of this study is to establish a specific procedure for design of a 9-story building with RC shear walls and GLT frames according to the performance-based design of KBC 2016. The performance objectives were set according to KBC and the acceptance criteria for each goal were defined. The RC shear walls and GLT frames were designed by concrete and wood structure requirements, respectively. Analytical models were developed to reflect their nonlinear features, and both nonlinear static and dynamic analyses were conducted. Performance evaluation results showed that the shear walls have insufficient shear strength, so they were re-designed. Consequently, it has been confirmed that GLT frames can be applied to a 9-story office building with the assistance of RC shear walls and performance-based seismic design.

Optimizing the coupling ratio of seismic resistant HCW systems with shear links

This paper investigates through nonlinear static and dynamic analyses the behaviour of a newly introduced steel and concrete hybrid coupled wall (HCW) system made by a single reinforced concrete (RC) wall coupled to steel columns by means of steel links, a structural solution of potential interest for seismic-resistant multi-storey buildings. The considered HCW is conceived as seismic resistant system where the RC wall and the steel columns remain undamaged while the seismic energy is dissipated by yielding concentrated in the steel links only. In order to achieve such a desired seismic behaviour, a proper design procedure must be adopted and validated. Accordingly, this study reviews a recently proposed design approach and presents some modifications to further improve the seismic behaviour of the considered HCW system. Case studies are designed using the proposed modified design method as well as its former version. Afterwards, the seismic behaviour of the considered case studies is analysed to identify the optimal degree of coupling between the RC wall and steel columns, also evaluating the influence of the building height and uniform or non-uniform distribution of shear links. The obtained results confirm the improvements of the modified design method proposed in this study and provide support for the selection of the design parameter that influences the most in the seismic behaviour of the innovative HCW system, i.e. the degree of coupling between RC wall and steel columns, controlled by the adopted steel links.

Mix design and properties of fly ash waste lightweight aggregates in structural lightweight concrete

Concrete is one of the most widely used construction materials and has the ability to consume industrial wastes in high volume. As the demand for concrete is increasing, one of the effective ways to reduce the undesirable environmental impact of the concrete is by the use of waste and by-product materials as cement and aggregate substitutes in concrete. One such waste material is fly ash, which is produced in large quantities from thermal power plants as a by-product. A substantial amount of fly ash is left unused posing environmental and storage problems. The production of sintered lightweight aggregate with fly ash is an effective method to dispose of fly ash in large quantities. Due to lack of a proper mix design procedure, the production and application of lightweight aggregate in structural concrete are not much entertained. The absorption characteristic of lightweight aggregate is a major concern, while developing the mix proportioning of lightweight concretes. The present study is an attempt to establish a new mix design procedure for the development of sintered fly ash lightweight aggregate concretes, which is simple and more reliable than the existing procedures. Also, the proposed methodology has been validated by developing a spectrum of concretes having water cement ratios varying from 0.25 to 0.75. From the study, it is obvious that the development of 70MPa concrete is possible by using cement alone without any additives. Also, it is ensured that all the concretes have densities less than 2000kg/m3.

Two-Phase Interleaved Boost Converter Using Coupled Inductor for Fuel Cell Applications

This paper investigates the benefits of directly coupled and inversely coupled inductors compared to the conventional uncoupled inductors. The coupled inductors using two phase interleaved boost DC-DC converter is used for high power and high performance applications. The advantages of the coupled inductors interleaved boost converters include increased system efficiency, reduced core size, current ripple reduction. The focus is to develop useful design equations for the operation of the interleaved boost converters under continuous conduction mode (CCM). The effects of the direct and inverse inductors has a key benefit of converter performance parameters such as inductor ripple current, input ripple current, which should be less than 4% of its nominal value of the input current for the longer life span of fuel cell and achieving stable CCM operation. The inductors are modeled in Matlab® Simulink to simulate and evaluate the performance of the DC-DC boost interleaved converter with proper design procedure of directly coupled, uncoupled and inversely coupled inductors for fuel cell applications having maximum output power of 1kW, 28.8 V and 35 A at the output voltage of 120 V.

Possibilities and limitations of innovative retrofitting for masonry churches: Advanced computations on three case studies

The use of fiber reinforced polymers (FRP) represents an interesting option to inhibit the formation of partial collapse mechanisms on macro-blocks, which is a typical failure mode shown by masonry churches under seismic actions. Furthermore, FRP strips exhibit a very good performance at failure, low invasiveness and high speed of execution. This study provides an insight into the possible applications of FRP on three masonry churches damaged by the 2012 Emilia seismic sequence. Several different linear and non-linear analyses are carried out, including standard response spectrum analyses, limit analyses with both pre-assigned failure mechanisms and Finite Elements (FE), pushover and non-linear dynamic analyses. A remarkable consistency is found between the real seismic performance of the churches and the results obtained through both limit and advanced non-linear dynamic analyses. In particular, both the damage distributions and the active failure mechanisms derived from the numerical analyses are consistent with those observed on the churches after the seismic event. A seismic upgrading of the churches through the application of FRP is proposed, using a proper design procedure based on comprehensive advanced FE computations, with the aim of obtaining the required seismic performance and limited invasiveness. The interaction between FRP strips and masonry substrate is accounted for assuming the FRP behavior in agreement with Italian Guidelines for strengthening with composite materials (CNR DT200). It is found that through a rational design procedure of the FRP strengthening intervention it is possible to prevent the premature collapse of the macro-elements, considerably increasing their load carrying capacity.

Semiperiodicity versus periodicity for ultra broadband optical absorption in thin-film solar cells

We propose the use of one-dimensional semiperiodic front and back gratings based on Thue–Morse, Fibonacci, and Rudin–Shapiro (RS) binary sequences as promising photon management techniques for enhancing ultra-broadband optical absorption in thin-film solar cells. The semiperiodicity allows an aggregate light in-coupling into the active layer within the range of the solar spectrum that is less weak compared to an inherently broadband random grating, but has a much larger bandwidth than the strong in-coupling via a periodic grating configuration. The proper design procedure proposed here deviates from a canonical double grating synthesis as it adheres to an ultra-broadband design where the spectrally integrated absorption in the active material is the proper subject to optimization, leaving the grating perturbations just a measure to perturb and mold the trapped light field in the active layer accordingly. It is shown that by using a well-defined RS double grating in a 400-nm thick crystalline silicon solar cell, a 110.2% enhancement of the spectrally integrated optical absorption can be achieved relative to the reference case without grating.