Effects of different operating parameters in papaya halwa drying

An experimental study was performed to determine the drying characteristics of dried papaya using different drying methods. They were dried using several methods, such as sun drying, solar drying, oven drying, and microwave drying. The effects of different operating conditions on physical quality attributes were investigated. The papaya were cut into different thicknesses and cooked in sugar syrup with different sugar concentration for 24 hours. Three different temperature settings were used in oven and microwave drying. The drying curve and drying rate of each method, temperature, sample thickness and sugar concentration were studied. The drying times were found as in 6-15 minutes, 5 to 11 h, 10 to 18 h, and 14 to 23 h for the microwave, oven, sun and solar drying, respectively. The drying time increased with the increase of sample thickness and sugar concentration, as well as with the decrease of the drying temperature. In this study, quality attributes like colours and textural property of dried papaya were explored. Among the various methods of the drying characteristics of papaya halwa, oven drying was preferred with the optimum sample in 5 mm thickness and at the air temperature of 70oC as it saved up to 40% of the drying time as compared to other methods, except microwave, and produced acceptable physical quality of product

Anti windup implementation on different PID structures

Although there have been tremendous advances in control theory over the last 25 years, the PID controller remains very popular and is still widely used in industry. A vital aspect of its implementation is the selection of a suitable set of parameters, as an improperly tuned controller might lead to adverse effects on process operation and worse, cause system instability. In industry, there are various types of PID controllers in addition to the 'textbook' PID but most tuning methods were developed based on this ideal algorithm. Another issue that is always associated with PID controllers is integral windup and the most popular method to overcome this problem is to add an anti windup compensator. This article includes the assessment of three anti windup strategies in combination with different tuning methods. The characteristics of PID controllers tuned using these approaches are evaluated by application to simulated FOPTD processes with different time-delay to time-constant ratios. Different measures were used to assess their performance and robustness properties, and the applicability of the tuning relationships to more typical (non-ideal) PID controllers is also considered. In general, the anti windup compensators successfully reduced the degradation effect caused by integral windup. It was found that the effectiveness of the different anti windup schemes varied depending on controller tuning methods and controller structures

Neural network based adaptive PID controller of nonlinear heat exchanger

This research presents the design and simulation of nonlinear adaptive control system on the heating process of shell-and-tube heat exchanger model BDT921. Shell-and-tube heat exchanger is a nonlinear process and change in process dynamics cause instability of the PID controller parameters i.e proportional gain, integral time and derivative time. Thus, the PID controller parameters need to be repeatedly retuned. In this study, neural network approach was introduced to auto-tune the controller parameters. The dynamic data from the BDT921 plant was collected to formulate the mathematical model of the process using MATLAB System Identification Toolbox. NARX model was used to represent the heat exchanger. Neural network was used as adaptive system to the PID controller. The neural network model consists of 4 input variables and 4 output variables. Single hidden layer feed forward neural networks with 20 neurons in hidden layer is the optimum topology of the network. The effectiveness of the controller was evaluated based on the set point tracking only. Simulation result proved that the adaptive PID controller was more effective in tracking the set point with faster settling time and lower or no overshoot respond compared to conventional PID controller

Simulation and control of spray drying using nozzle atomizer spray dryer

Spray drying is a commonly used method of drying a liquid feed through a hot gas. This study aims to obtain the empirical model of the spray drying process of full cream milk using a nozzle atomizer spray dryer, Lab-Plant SD 05 Laboratory Scale Spray Dryer. Inlet air temperature was chosen as the manipulated variable and outlet air temperature was the controlled variable. No disturbance was considered in this process. The model was obtained from empirical model development and it can be represented using first order plus time delay (FOPTD). The empirical dynamic model of the spray drying of full cream milk was simulated using SIMULINK to evaluate the performance and robustness. The PI and PID controllers were applied to implement the control strategies of the process. The effects of parameter uncertainties were investigated. From the observation, the direct synthesis tuning method has been found as a good controller tuning for both controllers in spray drying control system

Performance Evaluation of Portable Hot Water Jet for Frozen Meat Industry Application

High temperature-induced water jet has important cleaning factors for effective cleaning at food industries because it can provide mechanical, heat, and chemical effects during cleaning. It can also reduce cleaning time, labor load, and utility consumptions, hence reducing the operating costs and enhance sustainability. However, it has not been used widely in small and medium food industries due to a lack of cleaning awareness and small budget allocation for cleaning and disinfection. In this article, we evaluated the performance of a portable water jet in the laboratory before it was introduced to the frozen meat industry. Removal of invisible fat-based fouling deposits which remained on the surfaces of the meat processing equipment is quite a challenge. In this work, stainless steel surfaces were fouled with the fat-based fouling deposit. The fouled stainless-steel surfaces were used for the cleanability tests. The tests were conducted at different parameters which were cleaning parameters (temperature (35 °C and 65 °C) and cleaning detergent presence), cleaning operations (nozzle distances (5 cm and 30 cm)) and surface geometries (vertical and horizontal) which representing the different equipment’s geometry. Physical cleanliness (visual and touch) and protein residue swab test was used as the cleaning indicators. The target cleanliness was achieved at a high cleaning temperature of 65°C and with the presence of cleaning detergent. Results from these tests will be used as a guide to design an optimal cleaning program for SMEs frozen meat patty factory

Palm oil quality monitoring in the ripening process of fresh fruit bunches.

This research is done on oil palm (Elaeis guineensis) Tenera variety (A cross between Dura and Pisifera) on 8-year-old palms planted in 2003 at the Malaysian Palm Oil Board (MPOB) Research Station to aim of palm oil quality monitoring during the ripening process of fresh fruit bunches. The maturity and palm oil development in the fruit ripening process is a good way to harvest time monitoring and recommendation to evaluate the palm oil performance in food industries. Fresh Fruit Bunches were harvested from designated palms (January till May of 2010) and were divided into three regions (Top, Middle and Bottom) where fruits from the outer and inner layers were removed randomly during the ripening process between 8, 12,16 and 20 weeks after anthesis (WAA) to evaluate of oil development in mesocarp and kernel also investigate of fatty acid changes during the ripening process at each three regions of bunch by Gas Chromatography. Calculation of earned data related to ripening time and oil content was done by MSTAT-C and Microsoft Excel computer programs

Antioxidant activity of spearmint (Mentha spicata L.) leaves extracts by supercritical carbon dioxide (SC-CO2) extraction

In this study, the effects of pressure (100–300 bar), temperature (40–60ºC) and co-solvent flow rate (3–9 g/min) on antioxidant activities of supercritical carbon dioxide (SC-CO²) extracts of spearmint leaves were determined using full factorial in the frame of complete randomize design (CRD). The antioxidant activity of SC-CO² extracts was determined by DPPH radical scavenging method. The results showed that extraction pressure, temperature and co-solvent flow rate had significant effect (P < 0.05) on antioxidant activity of extracts obtained. The highest antioxidant activity (71.00 ± 2.65%) was obtained at 200 bar pressure, 50ºC and 6 g/min co-solvent flow rate. However, all of the extracts obtained in this study had significantly higher antiradical activities varying from 35.62 ± 0.34% to 72 ± 3.17% compared to butylated hydroxytoluene (BHT) as a reference. These results indicated that supercritical carbon dioxide is a promising alternative process for recovering compounds of high antioxidant activities from spearmint leaves

Biological performance of Asian catfish (Clarias batrachus) (Teleostei, Clariidae) cultured in recirculating aquaculture system

The study was conducted to assess the biological performance of Asian catfish in RAS by using 4 tanks (3 culture tanks and 1 sedimentation tank) measuring 2 m x 1 m x 0.60 m with a volume of 900 liters and bio-filter as water purification unit. The numbers of catfish cultured in each tank were as many as 300 fish i each tank, with a size of 5-8 cm (Tank 1), 8-12 cm (Tank 2) and 12-15 cm (Tank 3), respectively. This study was conducted for 30 days (August-September 2010) by considering the water quality during experiment, indicates that the RAS are able to provide proper conditions for growth and survival of catfish with a survival rate more than 92% on all tank experiments with specific growth rate from 0.64 to 0.89% per day and feed conversion rate of about 0.18-0.27. The existence of the impurities from the fish waste directly influences water quality, but the decline of water quality still at a decent level for the culture of catfish. The ANOVA test to the biological performance and water quality showed that the difference in the size of fish in each tank has no significant influence between each other

Effect of raw material variation, process variables and device stability on drying process of rambutan (Nephelium lappaceum L.) seed

This study was conducted to determine the influence of raw material variation, equipment process variables and device stability on the drying process of rambutan seed using oven and microwave drying equipments. The raw material variations studied were skin colour (yellow and fully red), storage period (fresh and stored) and seed mass (5 and 10 g). The important equipment process variables studied were oven temperature (40 and 60°C) and microwave power (250 and 1000 W).The output power and drying distribution in the drying chamber were studied to examine the device stability. Results indicated that the seed mass, oven temperature and microwave power influenced the drying time. The skin colour and storage period were negatively correlated with drying time due to drying time speculate to relay on time required for moisture removal that associated to initial moisture content and seed mass. It is also observed that the drying time will be shorten if the sample was located at the central of the microwave drying chamber. In contrast, the oven exhibited higher stability compared to microwave due to its ability to provide similar level of heating at each location in the drying chamber. This information will aid researchers and industrial operators to design an effective drying process using microwave and oven thus reducing cost and time

Analytical formulation of the integral square error for linear stable feedback control system

The paper aims to introduce a method for the analytical formulation of the integral square error (ISE). In this manner, the aim of the research is to create a parametric solution of the ISE for linear continuous feedback control systems while the closed-loop system is stable and the difference between reference and output, or error, is strictly proper. The potential advantage of this technique is that it allows the finding of an analytical solution for the ISE criterion and hence it is well adopted when a parametric solution of the ISE for optimal control problems is needed. This method is also superior to the numerical methods, because it returns the exact solution of the ISE. Comparisons with a powerful numerical method are given to validate the proposed method