This work mainly focuses on applying the passivity concept to a mass exchanger network. Development of the mass exchanger state space model with controller design is proposed. The state space equations of the mass exchanger model have been developed based on assumptions a of lumped parameter system, including well mixing rich and lean streams, a linear equilibrium relation over the operating range and isothermal and isobaric conditions. The mass exchanger model is characterized as a non-passive system due to its positive passivity index, and according a weighting function is introduced to shift the system to passive region along with the controller tuning. A case study of a five-streams mass exchanger network with four control loops is demonstrated using a weihing function to again counter the non-passive characterstic. Multi-loop passive PI controllers of the mass exchanger network are developed. This passive control configuration is tested by both disturbance rejection and set-point tracking. The designed passive controllers are able to completely eliminate the impact of disturbance effects, and all control loops show good performance to track 4, 15, 3 and 1.5% change of the set-points.
Portland cement blended Calcium Sulfoaluminate-belite (CŜAB) cements were studied in order to improve its binding properties and workability for specific applications. The binders consisted of calcium sulfoaluminatebelite, Flue Gas Desulfurization-gypsum and Ordinary Portland Cement (OPC). In this research, effects of OPC contents (25, 50, 75 wt%) as a CŜAB replacement on hydration behaviors and physico-mechanical properties of the binders were observed. Used CŜAB cement was synthesized using industrial by-products viz., fly ash, Flue Gas Desulfurization-gypsum, Al-rich sludge as starting materials via hydrothermal-calcination method. The results revealed that the replacement of CŜAB cement with OPC extended the setting times of pastes. The reduction of hydration rate with higher OPC content was due to dilution of fast setting phases such calcium sulfoaluminate and mayenite. Hydration products of calcium sulfoaluminate cement were ettringite responsible for high early strength together with Al(OH)3. From 6 h onwards, hydration of tricalcium silicate phase from the OPC generated calcium silicate hydrate. Stratlingite was also found in low OPC content mix resulting from the reaction between the Al(OH)3 and either alite phase in OPC or belite phase in CŜAB cement. Ettringite could also react with Al(OH)3 to generate monosulfate at later ages. The calcium sulfoaluminate phase was mainly responsible for the early mechanical properties, while OPC played an important role to improve strength at later ages.
Objectives of this research are to create the model that can be used to forecast natural rubber price of Thailand with independent variables such as world natural rubber price, synthetic rubber price, Advance market price of Tokyo Commodity Exchange (TOCOM), consumption of natural rubber, production of natural rubber with Autoregressive Integrated Moving Average (ARIMA) model. The study is divided as 4 procedures; first is time series analysis for forecasting natural rubber price of Thailand. It was found that the ARIMA(1,0,1) model is most suitable that can be explained for variations of natural rubber price of Thailand for 94.54% with Mean Absolute Percentage Error (MAPE) of 5.923. the second step is ARIMA analysis for forecasting natural rubber price of Thailand together with independent variables, it was found that ARIMAX(0,1,1) was most appropriate with variation explanation of Thailand’s natural rubber price of 99.89% and MAPE of 1.11. The third step is model analysis to forecast independent variables and the last step is using values from independent variable forecast in the third procedure to forecast Thailand's natural rubber price.
This work studied the effect of interaction between active metal species (Ni and Ni-Co species) and different support (Al2 O3-MgO and SiO2) on the catalyst properties and catalytic performance in dry methane reforming reaction. Supports were synthesized by sol-gel method, then the catalyst samples were prepared by incipient wetness impregnation with a salt solution of active metal(s). The fresh catalysts were characterized via Scanning Electron Microscopy (SEM), Temperature Programmed Reduction (TPR) and Temperature Programmed Desorption (TPD) techniques. Dry Methane Reforming (DMR) activities were tested in a conventional fixed-bed reactor at 620°C. The SEM images and H2-TPR results reveal that the Strong Metal Support Interaction (SMSI) takes place in the catalysts based on Al2 O3-MgO support. The metal dispersion and average metal particle size were evaluated using TPD results. It was found that a Ni-Co bimetallic catalyst provides higher metal dispersion and smaller average metal particle size than Ni monometallic catalysts due to the effect of metal-metal interaction. The bimetallic catalyst with weaker metal-support interaction improve the metal-metal interaction resulting in increasing higher metal dispersion. DMR test presented that sites of strong metal-support interaction enhanced CH4 activity. The stronger metal-metal interaction in Ni-Co bimetallic catalyst with SiO2 support promoted CO2 activity.
The purpose of this report is to analyze the heat recovery of the Heat Pipe Heat Exchanger (HPHE) by using ethanol as the working fluid. Heat pipe heat exchanger consists of 90 tubes were placed in staggered arrangement and inside the heat pipes was contained a screen wick and a working fluid. These pipes have been divided into three zones, consisting of evaporation zone, adiabatic zone, condensation zone, in each of zone, has a length of 500 mm, 100 mm and 500 mm, respectively. The mathematical models of HPHE which were simulated in MATLAB have the hot air flowing to evaporation zone with temperature range of 423.15 to 498.15K, and the cold water flowing to the condensation zone with a constant temperature of 303.15K. The ratio of hot air heat capacity rates to water heat capacity rates (C*) are in the range of 0.50 to 1.50. The results showed that the C* is 1.50 and the hot air temperature of 498.15K to be provided the best temperature for an exit cold water flow. The heat transfer coefficient of the hot air flowing to evaporation zone is 99.66 W/m2.K as well as the heat flux of condensation zone is 23.226 W/m2. Furthermore, at C* = 0.50 and the hot air temperature inlet of 423.15K, showed the best effectiveness equal to 0.538. Therefore, the results of the HPHE simulation can be used to design for the boiler in distillery.
The objective of this study was to optimize the condition for fish protein hydrolysate production from minced by-catch fish by using hydrochloric acid and 2 protease enzymes; Papain and Alcalase. Taguchi design and Central Composite Design (CCD) were applied for experimental design to evaluate the degree of hydrolysis. Response surface methodology was performed in order to determine the optimal production conditions. The optimal condition for acid hydrolysis was 4 mol/L of hydrochloric acid at 100 o C for 90 minutes which yielded 50.70% degree of hydrolysis. For enzymatic hydrolysis, Alcalase is the most suitable protease enzyme for fish protein hydrolysate production. The optimal condition was 6 % (w/w) Alcalase concentration at the temperature of 61.23 o C and the reaction time of 27.36 minutes resulting in 88.9% of degree of hydrolysis. Amino acid profiles of fish protein hydrolysates hydrolyzed under the optimal condition were analyzed by HPLC and the results showed that fish protein hydrolyzed by Papain had highest nutritional properties. Glutamic acid had the highest percentage (16.35%) followed by Aspartic acid (10.41%) and Lysine (8.48%).
This paper presents an Artificial Intelligence (AI) based approach uniquely applied to Permanent Magnet DC motor actuator for position control. The AI method employed in this work is Fuzzy logic. A first order lag Sliding mode controller is tuned and combined with an Adaptive Fuzzy- PI controller architecture which operates in parallel. The controller architecture proposed in this study is aimed at improving the disturbance rejection capability, steady state as well as transient performance of the conventional Adaptive Fuzzy-PI controller and sliding mode controller. Hence, the robust control law of the proposed controller (SM+FZ-PI) consists of a discontinuous Sliding mode output added to a continuous Adaptive Fuzzy-PI controller output. The sliding mode controller switches on only when disturbance in the system is detected. The performance of the proposed controller architecture has been compared with a conventional PID and Adaptive Fuzzy-PI controllers for performance evaluation with respect to several operating conditions such as load torque disturbance injection, noise injection in feedback loop, motor non-linearity exhibited by parameters variation, and a step change in reference input demand. The proposed controller (SM+FZ-PI), had the best disturbance rejection and steady state error elimination.
Application of mechanical pretreatment in lignocellulosic biomass using screw press or extruder pretreatment recently gained more interest due to high shear, rapid mixing, short residence time, no inhibitor formation (e.g. furfural and HMF), and moderate operating condition. Eventhough, the physical structure of biomass can be modified through this process, the lignin is stay still. This remaining lignin cannot be removed and it subsequently inhibits the enzyme activity to hydrolyze cellulose and hemicellulose. Therefore, the chemical addition to remove lignin is considered as the option to combine with mechanical pretreatment to improve the overall pretreatment efficiency. This review provided the study cases focusing on the feasibility of this process and the selection of suitable chemicals in order to implement this process to practical applications in industries.
Application of mechanical pretreatment in lignocellulsic biomass using screw press or extruder pretreatment recently gained more interest due to high shear, rapid mixing, short residence time, no inhibitor formation (e.g. furfural and HMF), and moderate operating condition. Even though, the physical structure of biomass could be modified through this process, the lignin is stay still. This remaining lignin cannot be removed and it subsequently inhibits the enzyme activity to hydrolyze cellulose and hemicellulose. Therefore, the chemical addition to remove lignin is considered as the option to combine with mechanical pretreatment to improve the overall pretreatment efficiency. This review provided the study cases focusing on the feasibility of this process and the selection of suitable chemicals in order to implement this process to practical applications in industries.
Data is recognized as an important corporate asset. Organizations use data in planning and decision making. However, data interpretation is the most important issue. In order to interpret the data clearly and efficiently, data visualization concept helps people understand the significance of data by placing it in visual context. This paper aims to provide a framework to create a web-based data visualization with Google charts. The framework was designed and developed based on MVC pattern. The MVC pattern is very useful for the architecture of web applications, separating the model, view and controller of a web application. In addition, the framework also was designed to connect a database that users can retrieve data from database to create web-based data visualization. Through this experimental development, we use White-Box testing for the code verification in the model module. Lastly, a web page example is shown to illustrate the process and result from the use of this framework.
Gel-spun UHMWPE fibers were produced without an extracting process. Decalin solvent in gel fibers was evaporated rapidly in the first hour and reached equilibrium state after about 24 hours. WAXD patterns shows that the full concentric circular rings were observed for the as-spun fiber and transform into oriented fibers with azimuthal spots on the equator after hot-drawing process. Consistent with the results of DSC thermograms, with DR values greater than 5.0 found the newly developed endothermic peak of the drawn UHMWPE fibers at 150–155°C are attributed to the transition of the constrained orthorhombic into hexagonal crystals. In this study, UHMWPE fiber with modulus as high as 26 GPa and strength about 1.4 GPa can be achieved.
Understanding of mechanical behaviour of food particles will provide researchers and designers essential knowledge to improve and optimise current food industrial technologies. Understanding of tissue behaviours will lead to the reduction of material loss and enhance energy efficiency during processing operations. Although, there are some previous studies on properties of fruits and vegetables however, tissue behaviour under different processing operations will be different. The presented paper is a part of FE modelling and simulation of tissue damage during mechanical peeling of tough skinned vegetables. In this study indentation test was performed on peeled and unpeeled samples at loading rate of 20 mm/min for peel, flesh and unpeeled samples. Consequently, force deformation and stress and strain of samples were calculated. The toughness of the tissue also has been calculated and compared with the previous results.
One of the most critical challenges faced by many manufacturing industries is to produce high quality products using cost-efficient methods and tools in the shortest possible time and at the lowest operating costs. Many past researches had shown that in order to reduce setup time and manufacturing costs it need for fast setups and changeovers. Single Minute Exchange of Die (SMED) is one of the Lean Manufacturing System (LMS) tools used to measure setup and changeover efficiency. Setup time reduction is an important key parameter for improving manufacturing flexibility and reducing manufacturing costs. The three main objectives of this study are: first, to reduce machine setup time by 35% during a mould changeover; second, to identify the root causes of the bottlenecks operations; third, to propose and implement possible solutions to the bottleneck problems. SMED methods were applied at two major bottlenecks during setup operations, they are cast on strap and heat seal. Results and findings on the data analysis of the two bottlenecks before and after implementation of SMED are examined and analyzed. The setup operations performance is measured based on data analysis result with respect to machine setup time reduction. The result of this study shows significant reduction of cast on strap setup time to 54% and heat seal setup time to 47%. In other words, this study has achieved more than 35% of setup time reduction.
The electricity power generation plays the important role of every business or industrial, since it must be supplied to cove with the full consumption on demand sites. To keep with constant operating point of electric power generation of thermal process, the maintenance is the most crucial technique for preserving the deterioration or damage of equipments. In this research the thermal power plant of Electric Generation Authority of Thailand (EGAT) is selected to develop the maintenance system. Historical maintenance data of each unit of thermal plant must be retrieved. The data are classified and identified in four levels such as units, systems, equipments, and component. The data is characterized to database manner by using SQLserver and Visual C# 2005 is used for implementing the user program interfacing. The criteria level applies the combination of Failure Mode Effect Analysis (FMEA) and AHP approaches to find the critical ranking priority of failure mode relating to three criteria such as maintenance cost, man per hour working, line priority. In summary of this research, we analyze and develop the software for maintenance priority and management for thermal power plant. The developed software can help the maintenance team for making decision in spare part management and it is friendly-user to pursuit the maintenance policy focused on critical maintaining equipments in overall systems
Rising Prices of nickel and molybdenum in the past few years have led to unprecedented interest in substitution of leaner-content alloys for standard 300-series austenitic stainless steels in a lot of applications. Due to the high prices of different alloying elements and to periodic large fluctuations that cause similar large fluctuations in the costs of using 300-series stainless steels; a lot of new materials entered the markets in Europe and also in the rest of the world. A big disadvantage consists in the fact that there are a lot of corrosion results, however, a direct comparison of the corrosion resistance of these new materials does not exist up to now or only incompletely. In this project comparative investigations were carried out and always one or several representatives of a material group were incorporated. These material groups are: Lean Duplex Stainless Steels, Manganese Alloyed Austenitic and Duplex Stainless Steels and Ferritic Stainless Steels. These materials were investigated in a lot of different test procedures and in different conditions focused on the application in civil engineering and common use. Beside the electrochemical investigations all materials were exposed in different surface states in the atmosphere, once in coastal nearness and once in a city centre area. Other exposition tests with material coupons where done in the atmosphere of indoor swimming pools and at the case of food processing machines were corrosion processes are caused by the cleaning procedure. First results are reported
In many applications stainless steels need a hard and wear resistant surface. The common used austenitic stainless steels have excellent corrosion properties but very poor tribological characteristics. Depending on the demand of a high corrosion resistance there are only a few technologies to meet the necessary standard. A very successful process is the diffusion of carbon into the surface by the Kolsterising process which is done at very low temperatures so that no chromium carbides are precipitated. A high carbon content, dissolved in the lattice improves surface hardness and wear resistance by maintaining corrosion resistance. A surface hardness of over 1000 HV, a considerable improvement of wear resistance, an elimination of fretting (cold welding) and corrosion resistance in many hazardous environments are the results when Kolsterising is applied on austenitic stainless steels. Results of the influence of this hardening process on different properties of austenitic and duplex stainless steels are presented. Some examples for very successful applications of this surface treatment in different fields like automotive industry, medical industry, food processing and consumer industry are shown.
Thailand is one of the world’s first exporting countries of fresh and processed durians. Each year in the durian season, there are excess supplies of fresh durians which directly cause a decrease in durian price. The farmers sell their durians at a price which is actually lower than the production cost. This problem recurs every year. The purpose of this research is to design and develop the models which can effectively forecast the quantity of fresh durian production. Firstly, applying the four Time Series models, secondly, applying the Back-propagation Neural Networks (BPN) model to find an accurate forecasting model that can effectively forecast the quantity of durians in Thailand in advance. The findings of the research are the model of Back-propagation Neural Networks of the structure 4-8-1 equal to the least value of Mean Absolute Percentage Error (MAPE). It is in the good level of forecasting, and can be applied to forecast the fresh durian quantity effectively. After attaining the accurate forecasting model, this is applied with the Linear Programming (LP) model to assess the value of appropriate fresh durian in each region in the following year. The data of fresh and processed durians planning can be helpful to the farmer, as they can then make the maximum profit from selling their durians
Accurate rainfall forecasting is a crucial task for reservoir operation and flood prevention because it can provide an extension of lead-time for flow forecasting. This study proposes two rainfall time series prediction models, the Single Fuzzy Inference System and the Modular Fuzzy Inference System, which use the concept of cooperative neuro-fuzzy technique. This case study is located in the northeast region of Thailand and the proposed models are evaluated by four monthly rainfall time series data. The experimental results showed that the proposed models could be a good alternative method to provide both accurate results and human-understandable prediction mechanism. Furthermore, this study found that when the number of training data was small, the proposed model provided better prediction accuracy than artificial neural networks
Design teams are often expected to produce physical prototypes that demonstrate the working principles of the products they are designing within tight time-frames. The use of a ‘rapid prototype as design’ (RPaD) methodology, combined with the ability to effectively integrate the many existing and emerging virtual and physical rapid prototyping technologies into the development process increases the potential of producing new high technology products in shorter timeframes. The paper presents a set of case study projects, undertaken by product design students at Auckland University of Technology, in which extensive use was made of RPaD
This paper presents a master-slave operating technique for the material removal process aimed to be used for part prototyping. This system is designed for 5-axis milling processes which consist of a 6-DOF parallel haptic device as a master arm and a hybrid 5-axis H4 family parallel manipulator as a slave. According to the dissimilar structures between the master and slave, an operating technique to define positions and orientations of the slave’s end effecter or milling tool is applied in Cartesian space. Force reflection techniques in this work can help the operator move the master arm’s handle firmly along the virtual wall and generate significant feeling of force in master-slave milling tasks. The results of ball-end milling tasks show that each reproduced wooden work piece is similar to its referenced object with an average error of about 1 mm on each side and this master-slave operating technique can be used for dimensional scaling tasks.
