Abstract: A bilateral control system consists of two actuation systems which are separate but sends and receives information to and from each other. Information shared consists of calculated force and position readings from sensors which feed into the control system. When the actuation systems are in the form of robot manipulators, there are at least two degrees of freedom with each degree of freedom has its own force and position values. When these two systems operate simultaneously, a change in force and position for one system triggers the other to coordinate and attempt to maintain the same values of force and position at both sides and this is termed as a master-slave system. In most cases, both systems are identical and the amount of force and position desired is similar. In some real-life applications, the desired amount of force/position is scaled; i.e. smaller or larger force is desired at one end of the system (master/slave). For this purpose, this research proposes a method to scale the force at either master or slave side by using elements of the mass/inertia matrix of the robot manipulator. Four different scaling values were demonstrated in the experiments to show the validity of the proposed method. Results indicate that the method is viable as the forces were scaled correctly as desired.

Abstract: It is a general believe that the introduction of crack on a shell structure will considerably reduce the buckling load of the structure. This paper seeks to examine the effect of axial crack of a percentage of the axial length on the buckling and post-buckling behavior of axially compressed cylindrical shell structure. This is an experimental study involving six mild steel specimens with radius-to-thickness ratio, R/t = 50. The mild steel specimen is assumed to have a nominal thickness of 1 mm and the axial length-to-thickness ratio, L/R = 2.2. Cylinders had axial crack introduced to a fraction of the cylinder axial length. The magnitude of the crack length-to-cylinder axial length is varied between 0.05 and 0.5. Experimental results reveal that the load carrying capacity of the cylindrical shells is strongly dependent on the crack length, i.e., increasing the crack length leads to a decrease in the buckling load of the cylindrical shells. As an example, cylinder with axial crack extending by 20% of its axial length is enough to cause maximum reduction in the load carrying capacity of the shell (about 37% reduction).

Abstract: This paper presents an experimental study on the effect of different surface hardness to the foot kinematics during barefoot running using a multi segment foot model. Joint rotations during the stance phase of nine male subjects that running barefoot on three types of surface with different hardness level (concrete, artificial grass and rubber) was investigated experimentally. Screening process was conducted by evaluating the foot strike pattern among the subjects in order to eliminate the influence of the foot strike on kinematics response. Only heel strikers’ data was analyzed since most of the subjects performed heel strike during the experiment. Differences on joint rotation due to surface effects were analyzed using visual 3D software. The result showed that the pattern of joint rotation was slightly different when barefoot running on artificial grass compared to rubber and concrete surface. The significant difference was found in further investigation of the joint rotation during the mid-stance of the stance phase. The joint rotation was varied in the varying of the surface conditions, meanwhile group-based analysis in the present study did not imply the significant difference among the surfaces. No significant correlation was found in the present experiment between various surface hardness and joint rotations of foot kinematics segments. This study could provide additional insight on relationships between foot segment kinematics in term of joint rotations when running on different surface hardness..

Abstract: Effect of the weight additions of date seeds nanoparticles as a green inhibitor on the corrosion resistance of the rebar has been studied. Date seeds nanoparticles were added to the electrolyte solution (consists of water and sodium chloride in 3.5% conc.) in different weight fraction (1-5)wt.%. The results were shown that the sample without inhibitor that's submerged partially in only electrolyte solution have current corrosion high (I corr.=41.25 µA/cm2) than samples with inhibitor, while the sample in (3.5% NaCl) with concentration of inhibitor (1-4) wt.%, the density of corrosion current will be decreased as inhibitor concentration was increased. But when inhibitor addition reached to 5wt.%, the density of corrosion current will increase compared with the other concentrations. The results obtained from tafel method proven that the better corrosion resistance was at a ratio 4 wt.% of the powder date seeds. And from the economic viewpoint, the powder date seeds are almost cheaper compared with synthesis inhibitors so it is considered the best.

Abstract: Natural fibers have been known of its good acoustic damping properties. These agricultural by-products can be used in many aspects such as sound insulation. The main purpose of this study is to determine which natural fiber panels can deliver high sound transmission loss (STL). There are three different natural fibers will be utilized as the tested panels, which are coir, kenaf, and kapok fiber. The natural fiber panels will undergo the treatment and fabrication process before they can be used as a tested panel. The STL was measured using two microphones transfer function in the small scale of reverberation chambers. LMS Test Lab software coupled with LMS Scadas Mobile data acquisition (DAQ) unit is used to determine the sound pressure level in both chambers. The sound pressure level was recorded for both source and receiver chamber by having known sound power across the 16 tested one-third octave frequency bands between 125 Hz to 4 kHz. The results of STL has been analyzed and discussed in the discussion section. For selected frequency range, high frequencies (1 kHz and 3.15 kHz) are having low STL compared with low frequencies (125 Hz to 630 Hz). It is because lower frequencies sound wave could transmit better than higher frequencies sound wave through the panels.

Abstract: In this paper, the surface roughness and Knoop indentation micro-hardness behavior of aluminium oxide (Al2O3) and polystyrene (C8H8)n materials were investigated. This study was conducted experimentally. Thus, the mean value of the surface roughness, Ra, for aluminium oxide (Al2O3) was (Ra = 0.09 µm, ±SD = 0.01), whereas for polystyrene (C8H8)n it was (Ra = 1.95 µm, ±SD = 0.29). Here, the surface profile has some uncoated sites and/or deep valleys as the skewness, Rsk, tends to be associated with a negative value for both samples. The skewness, Rsk, and kurtosis, Rku, for aluminium oxide was -0.20 and 3.60, respectively, and for polystyrene was -1.41 and 6.45, respectively. Besides, the ratio of the two surface roughness profile (peak-to-valley) parameters Rq/Ra was about 1.22 (for aluminium oxide) and was about 1.35 (for polystyrene). Moreover, the total mean value and the total standard deviation value of the Knoop indentation micro-hardness for aluminium oxide (Al2O3) was (HK = 2072.4, ±SD = 120.8) and for polystyrene (C8H8)n was (HK = 18.6, ±SD = 1.38). Furthermore, the mean and standard deviation values of the elastic modulus for the aluminium oxide (Al2O3) material was (E = 372.95 GPa, ±SD = 9.4) with a Poisson ratio of v = 0.22, whereas, for the polystyrene (C8H8)n material it was (E = 3.03 GPa, ±SD = 0.1) with a Poisson ratio of v = 0.33.

Abstract: Inkjet printing has been seen promising in printing conductive inks on variety of substrates other than fabrics and it should be expanded to fabrics since fabrics with integrated electrical features able to form intelligent articles. This study presents the investigation on printing and curing of silver conductive inks track from modified on-shelf inkjet printer on fabric. Epson printer is selected for modification which conventional paper feeding concept is replaced with platform stage. The viscosity of the conductive ink is adjusted accordingly to prevent clogging. Variation of processing parameters including printing speed, deposition height, curing temperature and time were investigated and measurement of the dimensional accuracy of the printed pattern as well as mechanical and electrical test are performed and analyzed. The results obtained were as expected which the thickness of the ink tracks were very thin in the sub-micron range and multiple printing selection with suitable curing time and temperature are desired to generate ink tracks with compatible adhesion to the substrates and conductivity. Sample with low speed parameter and 0.15 mm deposition height resulted in dimension which is close enough to the targeted dimension. The used of modified on-shelf inkjet printer and DLP projector with hot plate are proven feasible to print and cure conductive ink tracks on fabrics.

Abstract: This paper presents experimental work on quasi static compression test of corroded circular tubes of aluminum AA 6063 T5. A new apparatus was developed to prepare corroded specimens. A lot of 26 specimens were prepared with variable exposure time to corrode, then to be compressed via universal testing machine. Values of Pmax, Pmean, and total energy absorption are reduced significantly when exposure time to corrode been prolonged, because of mechanical properties will be reduced when corrosion level at the worst. Several empirical models were established for corroded circular aluminum tubes with variable exposure time to corrode.

Abstract: This paper presents the results of experimental and numerical studies of semi-perforated V-gutter flameholders. The high-precision laboratory equipment helped to make measurements of the emission of nitrogen oxides, the exhaust gas temperature, the values of lean blowout and the parameters for calculating combustion efficiency. The analysis showed that fuel supply from the bottom part of the V-gutter makes it possible to burn the fuel more efficiently and allows for a wider combustion range. However, there is a higher emission of nitrogen oxides in the context of such fuel supply. In addition, fuel supply from the bottom part of the V-gutter provides a high exhaust gas temperature, which is very important when designing heat-generating systems. The numerical simulation of the combustion process behind V-gutter flameholders confirms the research findings and shows the physical side of combustion behind the recirculation zones of V-gutter flameholders. On the basis of microflame elements in the form of semi-perforated V-gutter flameholders, the authors present the model of a heat generator that can be used as a heat source for autonomous air heating of residential and office buildings, such as institutions of higher education. The authors also provide the performance calculations depending on the fuel consumption rate and the outside air temperature. The calculations confirm the high performance and reliability of the proposed circuit in all weather conditions of the heating season.

Abstract: In this approach, MATLAB has been used for theoretical investigation on performance of offset finned absorber solar air heater. The evaluation of parametric effect i.e. offset fin spacing ‘sf’ and offset fin height ‘hf’ and solar insolation ‘Io’ at different air mass flow rate on the thermal and exergy performance of solar air heater. Thermal efficiency (the first law of thermodynamic) and exergy efficiency (the efficiency of process taking the second law of thermodynamic in account), the results indicate that the exergy performance is effective at lower air mass flow rate, fin spacing and fin height, whereas the thermal performance at higher air mass flow rate. The exergy efficiency is the main factor for performance evaluation, results show that the trends of variation of the thermal and exergy efficiencies are not the same. The performances of offset finned solar air heater are compared with conventional flat plate solar air heater.

Abstract: Sustained stress has been well known as one of the contributions or root causes of failures at the point of stress concentration along the piping system. The importance of evaluation of sustained stress in operating condition have been deliberated for nearly two decades in numerous papers and books but there are still uncertainties in understanding its philosophy. Due to the presence of various types of pipe stress software in the market with different approaches of analysis, engineers frequently overlook the most important elements associates to computer methodology in terms of software capability that need to be considered in the analysis for addressing sustained stress problems. During operating conditions, piping system is subjected to combination of loading from weight, thermal expansion and any type of occasional load such as wind and earthquake. All of these loadings contribute stresses to the piping system. These stresses are divided into three main categories which are sustained, expansion and occasional. The evaluation of expansion and occasional stresses are mainly straight forward whereas sustained stresses need to be carefully evaluated against codes and standards. Sustained stress is always referred as sustained loading that is imposed in vertical downwards direction. This loading is generated from the piping material weight associated with density of carry-over fluid/medium, pipe insulation, valves, flanges and all other pipe fittings. The problems arise when this vertical downwards force is not supported by sufficient pipe support. This phenomenon occurs when the pipe move in upward position during operating conditions. At this stage, pipe may lift off from it supports in which point of stress concentration will be created along the system that can lead to hot sustained stress issue. This paper will demonstrate a methodology that can be applied to correctly evaluate the problems related to sustained stress in operating conditions using a pipe stress analysis software Caesar II, developed by COADE, now owned by Intergraph, Houston. From the results of computer analysis, the behavior of the piping system related to sustained stresses can be observed and predicted correctly. A solution to the said problem will also be demonstrated in this technical paper for future reference.

Abstract: Fuzzy logic technique has been proposed to control the hydraulic actuator operated active suspension system. The quarter car model has been used to simulate the mathematical model of active suspension system. The dynamic nature of suspension system and complex nonlinear characteristics of actuating system has increased the difficulty of creating mathematical model for active suspension system. In real time, the controller designed based on analytical method will not give better result due to its complex mathematical model. The fuzzy logic technique has able to give better performance for active suspension system irrespective of the complex nature of mathematical model of suspension system. This paper describes mathematical model of suspension system with hydraulic actuator and fuzzy controller in order to obtain vehicle response for range of road input. The simulation and experiment conducted on real time control platform will confirm the performance of fuzzy logic controller for active suspension system.