Effect of Humidity on Thermal Comfort in the Humid Tropics

This paper presents the main findings of the effect of indoor humidity on occupants’ thermal comfort in the humid tropics of Malaysia. An extensive field investigation was carried out in Kota Kinabalu city and the surrounding areas, located in East Malaysia. A total of 890 individuals were asked to complete a questionnaire. Measured indoor climates were also recorded. The survey was designed as cross sectional data collection. The present investigation found that the occupants were thermally comfortable at wide relative humidity range. The mean relative humidity corresponding to the optimum comfort temperature was close to 73%. Regression models failed to predict accurately the effect of relative humidity on occupants’ thermal perceptions. In addition, a quadratic regression model was developed for the prediction of the mean indoor relative humidity based on indoor temperature. The suggested regression model can be used for an approximate prediction of indoor relative humidity when required.

Electroless copper-phosphorus coatings with the addition of silicon carbide (SiC) particles

Cu-P-silicon carbide （SiC） composite coatings were deposited by means of electroless plating.The effects of pH values,temperature,and different concentrations of sodium hypophosphite （NaH2PO2·H2O）,nickel sulfate （NiSO4·6H2O）,sodium citrate （C6H5Na3O7·2H2O） and SiC on the deposition rate and coating compositions were evaluated,and the bath formulation for Cu-P-SiC composite coatings was optimised.The coating compositions were determined using energy-dispersive X-ray analysis （EDX）.The corresponding optimal operating parameters for depositing Cu-P-SiC are as follows：pH 9;temperature,90oC;NaH2PO2·H2O concentration,125 g/L;NiSO4·6H2O concentration,3.125 g/L;SiC concentration,5 g/L;and C6H5Na3O7·2H2O concentration,50 g/L.The surface morphology of the coatings analysed by scanning electron microscopy （SEM） shows that Cu particles are uniformly distributed.The hardness and wear resistance of Cu-P composite coatings are improved with the addition of SiC particles and increase with the increase of SiC content.

LCA studies for alkaline and enzyme catalyzed biodiesel production from palm oil

The life cycle analysis of biodiesel production from palm oil (PO) involves 3 stages: 1) Cultivation;2) Oil Extraction and 3) Transesterification of PO. There are several different approaches to the production process. The enzyme catalyzed process, was investigated and its environmental performance was compared with the conventional alkali-catalyzed process by using life cycle analysis (LCA). The enzyme catalyzed process is found to be technically a simpler production process and offers the production of less environmentally damaging wastes.

Effect of formulation of alginate beads on their mechanical behavior and stiffness

The aim of this work was to determine the effect of formulation of alginate beads on their mechanical behavior and stiffness when compressed at high speed. The alginate beads were formulated using different types and concentrations of alginate and gelling cations and were produced using an extrusiondripping method, Single wet beads were compressed at a speed of 40 mm/min, and their elastic limits were investigated, and the corresponding force versus displacement data were obtained. The Young＇s moduli of the beads were determined from the force versus displacement data using the Hertz＇s contact mechanics theory. The alginate beads were found to exhibit plastic behavior when they were compressed beyond 50% with the exception of copper-alginate beads for which yield occured at lower deformation, Alginate beads made of higher guluronic acid contents and gelling cations of higher chemical affinity were found to have greater stiffness. Increasing the concentration of alginate and gelling ions also generated a similar effect. At such a compression speed, the values of Young＇s modulus of the beads were found to be in the range between 250 and 900 kPa depending on the bead formulation.

DC Motor Speed Control Using SMS Application

Motors are normally used for industrial control, automation and home electrical appliance. It spans everything from residential washing machines, fans, hand-held power tools, automotive window lift, traction control system, industrial drives and many more. Motor application is not completed without a control system. The inventions of microprocessor and microcontroller make the control system become easier. This control system is basically controlling the switch, speed, and direction of motor. Control signal is generated by a switch that is connected directly to the control circuit. In order to control and monitor the motor, user need to be at the place where the switch is located. In this system, mobile phone is used as a control switch. By sending text message using short message service (SMS) which is a part of the Global System for Mobile Communications (GSM), control signal is sent wirelessly to the control circuit. By implementing GSM module on the control circuit of motor, it can enable the user to send text message that contain command from any mobile phone to that GSM module. The GSM module will receive the text command and send it to the microcontroller to be processed and converted into desired control signal. Controlling motor using SMS is really convenient and give mobility as the user is able to control and monitor the motor from anywhere as long as the places have coverage. Moreover, sending text message is considered very low cost and most of people have their own mobile phones and it already becomes one of the basic needs in life.

Size prediction of κ-carrageenan droplets formed in co-flowing immiscible liquid

The formation of K-carrageenan droplets in channel emulsification was experimentally investigated. The dispersed phase was vertically injected into co-flowing immiscible palm oil in the direction of gravity. This study focused on predicting K-carrageenan drop size using force balance analysis. The force balance model considers the interracial tension to be the solitary attaching force, while a combination of the drag force from the co-flowing palm oil and the body force of the extruding K-carrageenan liquid act as the detaching forces. The conventional model gave poor predictions for droplet size, with an average relative deviation of 23%. This large deviation could be attributed to necking phenomena and an underestimation of the drag force generated on the shear-thinning K-carrageenan solution. By incorporating correction factors, the average relative deviation of the force balance model dronned to 4%.