Parametric and nonparametric identification of shell and tube heat exchanger mathematical model

Parametric and nonparametric models of a shell and tube heat exchanger are studied. Such models are very important because they provide information about controlling a system operation. Without the model, the control task would be difficult for tuning of controller. For many years, researchers have studied these models; however, their models are still less satisfactory since they are not in general form. This problem is caused by two key issues, namely, multiple unknown parameters and highly nonlinear structures. Energy balances have been set-up for condition of unknown parameters which involved, among others, temperature, flow rate, density and heat capacity. The identification process produces a dynamic model of the heat exchanger which is developed based on a lumped parameter system. The model developed is single input single output whereas input signal is hot water flow rate and the output is cold water temperature. The general form of the model obtained could have parametric model structures such as auto regressive with external input, average auto regressive moves with external input, output error or box-jenkins. The study in this thesis aims to solve the general form through parametric and nonparametric models which has been proposed as candidate models. Both candidate models have been implemented and tested by applying several data sets constructed in lab experiments. The first finding is the derivation of the dynamic model in the general form of the transfer function in s domain, and it has been proven that it has parametric model structure. The second finding is the first order without delay time transfer function of the nonparametric model where they have gain is 35.20C and time constant 7200s. These have proven to fulfill that the measured experimental data contains calculated error that is no than more 2%. The third finding is the parametric model obtained has proven that the measured experimental data contains calculated error level that is very satisfactory, i.e. less than 1%. This error has been determined based on the final prediction error for each model structure used. The best model has been chosen, i.e. bj31131. It has the smallest values of the loss function and final prediction error of 0.0023, and it has high values of the best fits, i.e. 96.84%. Parameter optimization has been calculated to determine minimization or maximization of functions which involved the parameter studied. It is used to find a set of design parameters that can in some way be defined as optimal. The first until the third findings are minor contribution while the parameter optimization has been a major contribution

Evaluating the effect of the pin's length to the strength of double sides friction stir welded aluminum

Based on previous research, it is believed that the double side friction stir welding will improve the obtained joint. It is hoped the length of the pin broaden the strain hardened area (especially the interference zone) which in turn will produce the stronger joints. From tensile test data, the tensile strength does increase by the length of the pin. The maximum tensile strength of 183 MPa acquired from the 6.5 millimeter pin which is equal to 75% joint efficiency whilst the lowest is 42 MPa resulted by the 2.5 millimeter pin. The hardness test confirmed the existing of the strain hardening phenomenon, which was shown by harder materials at interference zone. Other supporting evidence is the micro structure photo. The photos showed that not only exhibits strain hardening the interference zone also yields finer dispersed micro structure that will provide stronger joint

Mechanical Properties of Medium Density Fibreboard Composites Material Using Recycled Rubber and Coconut Coir

Natural fibre reinforced composite has emerged as highly potential replacement for synthetic fibres. Various natural waste fibres have been adopted for various engineering applications. This paper investigates the mechanical properties of medium density fibreboard composites material fabricated using recycled rubber and coconut coir. The suitability of using recycled rubber and coconut coir as a raw material and polyurethane as a resin in the manufacturer of medium density fibreboard was also studied. The medium density fibreboards were fabricated at prescribed percentages of filler. The performance of composite was evaluated by its mechanical and physical properties. Experimental investigation indicated that the mechanical strength of medium density fibreboards such as modulus of rupture and modulus of elasticity increased with increasing board hardness. Overall, the results showed that medium density fibreboard had been produced with acceptable properties, thus providing alternatives to manufacturing and agricultures economic planning

The effect of pretreatment powder using ball mill and ultrasound on the properties of single cell solid oxide fuel cell

Solid oxide fuel cell (SOFC) is currently popular due to its capability to convert hydrogen into electricity directly from oxidizing hydrogen fuel. The SOFC is one of the expected renewable energy devices and green technology in the future because of less carbon dioxide production and no pollutant product. Performance of SOFC was influenced by morphology and microstructure of the material, starting particle size and particle’s distribution. This paper addresses the comparative evaluation of using pretreatment NiO/YSZ powder using ball mill and ultrasound processess on the performance of a single cell SOFC. The performance of solid oxide fuel cell was evaluated using scanning electron microscopy (SEM), X-Ray diffraction (XRD) and impedance spectroscopy, measured at room temperature. The results indicate that the treatment using ultrasound process is better than ball mill process due the total resistance is smaller and distribution particle is more homogenous

Implementing neural network for damage severity identification of natural kenaf fibre composites

The emergence of natural fiber as a potential alternative for glass fibre replacement has seen various development and investigation for various applications. However, the main issue with the natural fibre reinforced composites is related to its susceptibility to impact damage. This paper presents a preliminary case study of damage identification in Natural Fibre Composites (NFCs). The study involves a simple experiment of impact on a NFC panel. The strain data are measured using piezoceramic sensors and the response signal was investigated. Then an effective impact damage procedure is established using a neural network approach. The system was trained to predict the damage size based on the actual experimental data using regression method. The results demonstrated that the trained networks were capable to predict the damage size accurately. The best performance was achieved for an MLP network trained with maximum signal features, which recorded the error less than 0.50%

Damage size classification of natural fibre reinforced composites using neural network

Damage classification is considered as an important feature in pattern recognition, which led to providing significant information. This research work explores damage size classification for several impact events in natural fibre reinforced composites, which is based on the information provided by the ten piezoceramics (PZT) sensors. An Impact event produced strain waves which several data features were obtained through the response captured. An effective impact damage classification procedure is established using a multilayer perceptron neural network approach. The system was trained to predict the damage size based on the actual experimental data. The data features were mapped into five output class labels, presented as a target confusion matrix. The classification results revealed that the damage sizes were successfully mapped according to its respective class, with the peak to peak feature gives the highest classification rate at 98.4%

Finite Element Simulation on Damage and Fracture Properties of a Ring Cut from Filament-Wound Pipes with and without Delamination

The technological advances in various industries have increased the demands on new engineered material tremendously since conventional materials such as steel, failed to perform in severe conditions. Nowadays, composite materials especially fibre-reinforced plastic composites (FRP) are broadly being used in many engineering fields to manufacture critical components with high stress concentration, exposure to extreme surrounding or weight constraint. However, they often suffer from a characteristic weakness, i.e. they are prone to interlaminar damage, often in a form delamination. In order to assess the development and the consequences of such damage, interlaminar fracture properties are essential. In this study, the ring cut specimen from filament-wound pipes with and without delamination was modelled and simulated based on experimental work using finite element modelling to further assist the identification and determination of the fracture properties. Investigation also involves the effect of the delamination length to the Energy Release Rate, G. Comparison between 23mm delamination of simulation and experimental results from [7] is presented

A study of geo-polymer as alternative material in automotive brake pad

Todays, there are various of alternative materials that have been studied by many researchers in order to find the appropriate combination of brake pad manufacturing in the automotive industry. Some of the alternative materials that has being used including palm slag, banana peels, nutshell and others. This provide more economical benefit and also environmental preservation by utilizing the waste of natural fiber. In this study, geo-polymer brake pad has been prepare using the waste product which is barren soil. Barren soil is chosen as an alternative brake pad material candidate from natural resources as it consists of deserts, dry salt flats, beaches, sand dunes, exposed rock, strip mines, quaries, and gravel pits. This barren soil are mixed with another candidates such as binder, reinforcement, abrasives and lubricant following the standard formulation of brake pad manufacturing. In this works, three type of samples have been used. The elemental composition for sample 1, 2 and 3 are main content with 10%, 5%, 15% alumina and 10%, 15%, 5% graphite respectively. The physical properties of geo-polymer brake pads studied including hardness test and its morphology structure. Sample has been characterized based on two main parameters which are hardness test and morphology analysis. From the analysis, it was found that a prototype from sample 3 exhibit the highest hardness index compare to sample 1 and 2. Sample 3 hardness also much better compare to the conventional brake pad with 64% of the hardness increment. This finding also support by the morphological analysis, whereby the surface of sample 3 show a compact and flat surface with less cracking and porosity. From both parameter, it can be concluded that sample 3 has a great potential to become a suitable geo-polymer brake pad. Here, the composition of a combination alumina and graphite in all sample play as important role in enhance the hardness parameter for the potential brake pad prototype

A review on the mechanical and physical properties of natural fiber composites

Research on the use of natural fibers as replacement to man-made fibre in fiber reinforced composites have received more interest and opened up further industrial possibilities. Natural fibre presents many advantages compared to synthetic fibers which make them attractive as reinforcements in composite material. They come from abundant and renewable resources, which ensures a continuous fibre supply and a significant material cost saving to the plastics, automotive and packaging industries. The paper reviews the previous and current research works published in the field of natural fiber reinforced composite material with special reference in mechanical properties of the natural fiber reinforced composite