Development Of Tilt And Vibration Measurement And Detection System Using MEMS Accelerometer As A Sensor [TK7875. K45 2008 f rb].

Dalam projek ini, sistem pengukuran dan pengesan isyarat sudut miring dan isyarat getaran menggunakan meter pecutan MEMS yang mempunyai dua paksi deria X dan Y dibina dengan jayanya. In this project, a measurement and detection system to detect tilt angle signal and vibration signal using MEMS accelerometer which has two sensed axes X and Y was successfully developed

Synthesis And Application Of Zno Nanorods For Oxygen Gas Sensor

In this thesis, a high sensitivity and accurate gas sensor with operating temperature at room temperature has been successfully developed by using ZnO nanorods. A series of parametric studies via hydrothermal and PECVD have been carried out in order to synthesis a high dense and high aspect ratio of ZnO nanorods. It has been demonstrated that a high-density of ZnO nanorods with aspect ratio 15:1 can be successfully synthesized at an annealing temperature of 100oC and 3 hours growth duration for via hydrothermal. Meanwhile for PECVD, a high aspect ratio of 12:1 ZnO nanorods successfully synthesized at 4nm gold (Au) catalyst with chamber pressure of 700mTorr. SEM and AFM analyses showed that the formation of ZnO nanorods via hydrothermal is significantly influenced by the seeds particle morphology while for PECVD, the Au nanoparticle size and the proper ratio of vapors components are the major parameter affecting the ZnO nanorods growth. The grown ZnO from both samples is of the wurtzite crystal type based on raman shift E2(high) of 436cm-1.An electrical characteristics via four point probles been conducted and the results showed that the resistivity of the ZnO grown via hydrothermal and PECVD are 4.47×10−3Ω

Transfer Technology of Laser Engraving Machine for Vocational School in Tegal District

Background: The problems and challenges that occur in Vocational High Schools (SMK) today are curriculum used is not aligned with the competencies, SMK graduates are not absorbed in the business world and the industrial world, the lack of quality products, competency test facilities, cooperation between companies, government agencies, the business world, and universities. Some of the weaknesses can be overcome through synergy between universities and vocational schools through Community Service activities, one of which is regarding CNC-based machines. Contribution: The contributionof this program is that the Pancasakti University of Tegal, especially the Faculty of Computer Science Engineering in collaboration with SMK Negeri 1 Bumijawa, will carry out learning activities for laser engraving machine training to enhance students' knowledge and experience. Method: The learning model used is theory and practice. The theory is given before practical learning or integrated during practice and at the last meeting an evaluation is held. Results: Training activities through this community service program are divided into several activities, including socialization of the laser engraving training program, Implementation of Theory and practice regarding Laser Engraving Technology, Post-Training Evaluation. Conclusion: The conclusion of this program states that the participants can increase their knowledge and understanding of laser engraving machine technolog

Performance of Photogrammetry-Based Makeshift 3D Scanning System for Geometrical Object in Reverse Engineering

A three-dimension (3D) scanner is one of the important tools for digital reproduction of physical objects in reverse engineering. In some cases, a makeshift 3D scanner is needed immediately, such as for emergency spare parts reproduction. Thus, this research aims to investigate the feasibility of a low-cost makeshift 3D scanner using a mobile phone and the photogrammetry method in reconstructing digital 3D models of geometrical objects. A focus is given to the dimension accuracy of the reconstructed 3D models, which have been reproduced using images taken by a mobile phone, in comparison with the actual dimension of the scanned test pieces. To do so, four types of actual geometrical test pieces with dimension from 5 to 175 mm had been fabricated using CNC machine. 3D models of each test pieces had been developed using the photogrammetry method and compared with those developed using an industrial-grade high-end 3D scanner. It was found that mobile photogrammetry achieved an average accuracy of 97.2%, with minimum and maximum values of 83.3% and 99.9%, respectively. Geometrical dimensions less than 10 mm tend to have lower accuracy, while it was the opposite for dimensions over 150 mm. Furthermore, the scanning limit for either method was found to be a surface with a small tilting angle (less than 3 degrees). Nevertheless, photogrammetry method in combination with a mobile phone has the potential to be utilized as an alternative of a makeshift 3D scanning system with sufficient accuracy using commonly available tools

Performance of Photogrammetry-Based Makeshift 3D Scanning System for Geometrical Object in Reverse Engineering

A three-dimension (3D) scanner is one of the important tools for digital reproduction of physical objects in reverse engineering. In some cases, a makeshift 3D scanner is needed immediately, such as for emergency spare parts reproduction. Thus, this research aims to investigate the feasibility of a low-cost makeshift 3D scanner using a mobile phone and the photogrammetry method in reconstructing digital 3D models of geometrical objects. A focus is given to the dimension accuracy of the reconstructed 3D models, which have been reproduced using images taken by a mobile phone, in comparison with the actual dimension of the scanned test pieces. To do so, four types of actual geometrical test pieces with dimension from 5 to 175 mm had been fabricated using CNC machine. 3D models of each test pieces had been developed using the photogrammetry method and compared with those developed using an industrial-grade high-end 3D scanner. It was found that mobile photogrammetry achieved an average accuracy of 97.2%, with minimum and maximum values of 83.3% and 99.9%, respectively. Geometrical dimensions less than 10 mm tend to have lower accuracy, while it was the opposite for dimensions over 150 mm. Furthermore, the scanning limit for either method was found to be a surface with a small tilting angle (less than 3 degrees). Nevertheless, photogrammetry method in combination with a mobile phone has the potential to be utilized as an alternative of a makeshift 3D scanning system with sufficient accuracy using commonly available tools

Quantitative roughness characterization of non-gaussian random rough surfaces by ultrasonic method using pitch-catch and pulse-echo configurations

Fundamental study to quantitatively evaluate not only the root-mean-square (rms) roughness Rq but also skewness Rsk of non-Gaussian random rough surfaces by ultrasonic method is presented. In this work, Johnson distribution together with Kirchhoff theory have been employed to derive a newly proposed Johnson characteristic function, which provides a theoretical relationship among ultrasonic reflection coefficient, Rq and Rsk. Based on the characteristics of such relationship, an effective ultrasonic measurement method consisting of a pitch-catch and a pulse-echo configuration to quantitatively characterize Rq and Rsk has been proposed. A general guideline for such characterization method has also been suggested. The validation of the proposed method has then been conducted numerically in the case of an air-coupled ultrasound. Good agreements between the numerically estimated Rq and Rsk and the corresponding reference values thus confirm the validity of the proposed metho

Influence of citric acid on the physical and biomineralization ability of freeze/thaw poly(vinyl alcohol) hydrogel

This work reports the modification of freeze/thaw poly(vinyl alcohol) hydrogel using citric acid as the bioactive molecule for hydroxyapatite formation in simulated body fluid. Inclusion of 1.3 mM citric acid into the poly(vinyl alcohol) hydrogel showed that the mechanical strength, crystalline phase, functional groups and swelling ability were still intact. Adding citric acid at higher concentrations (1.8 and 2.3 mM), however, resulted in physically poor hydrogels. Presence of 1.3 mM of citric acid showed the growth of porous hydroxyapatite crystals on the poly(vinyl alcohol) surface just after one day of immersion in simulated body fluid. Meanwhile, a fully covered apatite layer on the poly(vinyl alcohol) surface plus the evidence of apatite forming within the hydrogel were observed after soaking for seven days. Gel strength of the soaked poly(vinyl alcohol)/citric acid-1.3 mM hydrogel revealed that the load resistance was enhanced compared to that of the neat poly(vinyl alcohol) hydrogel. This facile method of inducing rapid growth of hydroxyapatite on the hydrogel surface as well as within the hydrogel network can be useful for guided bone regenerative materials

Influence of citric acid on the physical and biomineralization ability of freeze/thaw poly(vinyl alcohol) hydrogel

This work reports the modification of freeze/thaw poly(vinyl alcohol) hydrogel using citric acid as the bioactive molecule for hydroxyapatite formation in simulated body fluid. Inclusion of 1.3 mM citric acid into the poly(vinyl alcohol) hydrogel showed that the mechanical strength, crystalline phase, functional groups and swelling ability were still intact. Adding citric acid at higher concentrations (1.8 and 2.3 mM), however, resulted in physically poor hydrogels. Presence of 1.3 mM of citric acid showed the growth of porous hydroxyapatite crystals on the poly(vinyl alcohol) surface just after one day of immersion in simulated body fluid. Meanwhile, a fully covered apatite layer on the poly(vinyl alcohol) surface plus the evidence of apatite forming within the hydrogel were observed after soaking for seven days. Gel strength of the soaked poly(vinyl alcohol)/citric acid-1.3 mM hydrogel revealed that the load resistance was enhanced compared to that of the neat poly(vinyl alcohol) hydrogel. This facile method of inducing rapid growth of hydroxyapatite on the hydrogel surface as well as within the hydrogel network can be useful for guided bone regenerative materials

Investigation of Low-Pressure Bimetallic Cobalt-Iron Catalyst-Grown Multiwalled Carbon Nanotubes and Their Electrical Properties

A bimetallic cobalt-iron catalyst was utilized to demonstrate the growth of multiwalled carbon nanotubes (CNTs) at low gas pressure through thermal chemical vapor deposition. The characteristics of multiwalled CNTs were investigated based on the effects of catalyst thickness and gas pressure variation. The results revealed that the average diameter of nanotubes increased with increasing catalyst thickness, which can be correlated to the increase in particle size. The growth rate of the nanotubes also increased significantly by ~2.5 times with further increment of gas pressure from 0.5 Torr to 1.0 Torr. Rapid growth rate of nanotubes was observed at a catalyst thickness of 6 nm, but it decreased with the increase in catalyst thickness. The higher composition of 50% cobalt in the cobalt-iron catalyst showed improvement in the growth rate of nanotubes and the quality of nanotube structures compared with that of 20% cobalt. For the electrical properties, the measured sheet resistance decreased with the increase in the height of nanotubes because of higher growth rate. This behavior is likely due to the larger contact area of nanotubes, which improved electron hopping from one localized tube to another

Water retention properties of a fused deposition modeling based 3D printed polylactic acid vessel

The applications of fused deposition modelling (FDM) based 3D printing have gone beyond merely simple prototypes to where functionalities are expected. One of such functionalities is the water retention properties, especially for fluid handling products, either completely waterproof or deliberately porous. Issues arise especially in determining crucial parameters and their optimization to achieve the desired water retention properties. This study established the relationship among printing parameters (layer thickness and wall thickness) and water temperature with leakage flow rate. A series of 3D printed polylactic acid (PLA) vessels were fabricated at various layer height and wall thickness. Then, the volumetric loss of water at various temperatures was measured, elapsed time was recorded, and the leakage flow rate was calculated for each 3D printed vessel. It has been found that the leakage flow rate decreased when layer height decreased, wall thickness increased, and water temperature decreased. Based on multilinear regression analysis, the magnitude of influence for the layer height was the highest, which could reach at a point where variation in wall thickness and water temperature had no effect. A regression model having 81.27% fitness that provided a quantitative relationship among all parameters had also been obtained. ANOVA analysis revealed that all parameters were statistically significant in optimizing as well as predicting the value of the leakage flow rate