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Journal of Technology and Social Science (JTSS, J. Tech. Soc. Sci.)

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Home > Archives > Vol.1, No.2

Vol.1, No.2






Finite Element Method for Narrow Slit Section Models Considering Air Viscosity                                      

Manabu Sasajima, Yue Hu, Takao Yamaguchi and Xilu Zhao 

Journal of Technology and Social Science, Vol.1, No.2, pp.1-5, 2017.

Abstract: This study deals with propagation of the sound waves in narrow slit section pathways. In very narrow pathways, the speed of sound propagation and the phase of sound waves change due to the air viscosity. We have developed a new finite element method (FEM) that includes the effects of air viscosity for modeling a narrow sound pathway. This method is developed as an extension of the existing finite element method for porous sound-absorbing materials. The numerical calculation results for several three-dimensional slit models using the proposed finite element method are validated against existing calculation methods. And relative error between the proposed method and the theoretical method was validated.

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Transmission Loss Analysis for Automotive Panel Laminated with Felt and Film and Felt

Yoshio Kurosawa, Naoyuki Nakaizumi and Manabu Takahashi

Journal of Technology and Social Science, Vol.1, No.2, pp.6-11, 2017.

Abstract: To reduce the interior noise of cars in the high frequency region, sound proof materials are laminated onto the body panels and interior trims. The sound proof properties of the laminate play an important role in efficient acoustical design. In this study, we developed a program code for predicting both the sound absorption and sound insulation properties of laminates. This program code uses the transfer matrix method based on the Biot theory and involves the vibro-acoustic coupling of a laminated structure with an elastic body (panel, film), porous body (felts), and air. First, we use a transfer matrix to express the properties of the individual layers (sound wave transmission inside the material and reflection properties on the surface). Then, we combine the individual properties in the actual lamination order to obtain the acoustic transmission properties of the entire lamination structure. In this report, we outline this program code and present our calculation results, which almost agree with the experimental results.

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Experiments on Chaotic Vibrations of an Arch Deformed by an Initial Axial Displacement

Shinichi Maruyama, Takao Yamaguchi and Ken-ichi Nagai

Journal of Technology and Social Science, Vol.1, No.2, pp.12-24, 2017.

Abstract: Experimental results are presented on chaotic vibrations of a shallow clamped arch subjected to periodic lateral acceleration. The arch is compressed by an initial axial displacement, then the lowest mode of vibration of the arch has asymmetric form to the mid span. The arch shows characteristics of soften-and- hardening spring involving snap-through transition. Chaotic responses including dynamic snap-through transition and internal resonances are inspected with the maximum Lyapunov exponents, the Fourier spectra and the Poincaré maps. Mode contributions to the chaos are examined with the principal component analysis. It is found among other conclusions that: In the chaotic response with the dynamic snap-through generated from the nonlinear periodic resonance of the lowest mode with the asymmetric form, the vibration mode with the symmetric form has dominant contribution to the chaos.

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Effects of the Cone on the Acoustic Characteristics of a Cone Loudspeaker

Yue Hu, Xilu Zhao, Qiong Wu and Manabu Sasajima

Journal of Technology and Social Science, Vol.1, No.2, pp.25-30, 2017.

Abstract: Loudspeakers are designed for reproducing the original sound field as faithfully as possible. In order to faithfully reproduce sound, it is important to understand the relationships among the physical characteristics of the loudspeaker. Vibration analysis of loudspeakers has been extensively researched over the years, but we believe that it has been insufficiently focused on the cone, which are important elements in loudspeaker design. This paper focuses on the cone which is important elements in the design of cone loudspeakers, and evaluates their effects on the acoustic characteristics of the loudspeaker. First, sound pressure frequency properties of a loudspeaker were measured in order to determine the characteristics of the cone loudspeaker. Next, a coupled analysis of vibration and acoustics that accounts was performed to verify the accuracy of the analysis. Finally, in order to design a loudspeaker with the desired acoustic characteristics, the response surface methodology was applied to obtain optimal cone and edge material properties.

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Damped Acoustic Analysis of an Automotive Cabin with Various Porous Media

Yoshio Kurosawa, Takao Yamaguchi

Journal of Technology and Social Science, Vol.1, No.2, pp.31-36, 2017.

Abstract: We created a test piece that simulates the upper back of a car. We measured the change in sound insulation from the sound-source side to the cabin side with breathable trim (urethane foam or felt). We created a finite-element model to calculate the acoustic-damping properties. Using urethane foam and felt to model the complex effective density and bulk modulus of the internal air, we sought the loss factor from the decay contribution of each sound-absorbing element employed in modal damping of the space. An experiment was conducted to verify this analysis, and it was found to be of sufficient accuracy, meaning that the sound-absorbing-material-thickness-dependent damping in an actual car could be accurately calculated by this technique.

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Electric Power Steering System Design Based on Linear Quadratic Control

Tomokazu Abe, Yu Fujimura,  Tatsuya Hirose, Seiji Hashimoto, Mitsunobu Kajitani, Ken Sato and Kazuhiko Gonpei

Journal of Technology and Social Science, Vol.1, No.2, pp.37-46, 2017.

Abstract: Electric power steering (EPS) systems are gradually replacing hydraulic power steering in modern cars. The main advantages of the EPS systems are their lower energy consumption and potential applications in autonomous driving. This paper discusses linear quadratic (LQ) control to reduce effort- and time-consuming manual tuning and to improve the steering feel compared to conventional map control. Moreover, a disturbance observer is introduced to estimate and suppress disturbances due to mechanical resonance and the self-aligning torque. The effectiveness of different combinations of these controllers is evaluated with simulations and hardware-in-the-loop (HIL) simulator-based experiments.

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An Observer Design Strategy in Electric Power Steering System

Jingying Lu, Wei Jiang, Tomokazu Abe, Yu Fujimura, Seiji Hashimoto and Mitsunobu Kajitani

Journal of Technology and Social Science, Vol.1, No.2, pp.47-53, 2017.

Abstract: In order to achieve precise state variables in electric power steering system, three types of observer considering applied disturbance are introduced. Disturbance is included in the observerfs state variables and defined as the step and lamp signals. Designed three observers are compared and evaluated through simulations and experiments. The simulation is carried out by the MATLAB/SIMULINK, and the experiment is investigated using the hardware in the loop (HIL) simulator technology. Experiments guarantee that 5th order observer can estimate the state variables with minimum error and noise, even though disturbance exists.

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Crystal Structure and Corrosion of Electrodeposited Ni-TiAlN Composite Coatings                                     

Esmar Budi, Muarief, Maulida Khasanah, Ade Lina Permatasari, Iwan Sugihartono, Riser Fahdiran and Agus Setyo Budi 

Journal of Technology and Social Science, Vol.1, No.2, pp.54-61, 2017.

Abstract: An investigation has been done to study the influence of various stirrer speed, electrodeposition current and substrate on the crystal structure and corrosion of electrodeposited Ni-TiAlN composite coating. To study the influence of stirrer speed, the composites were deposited on tungsten carbide substrate at various stirrer speed of low (1235 rpm), medium (1995 rpm) and high (2446 rpm) at fixed current while to study the effect of electrodeposition current, the composites were deposited on tungsten carbide at various current of 2, 3 and 4 mA at fixed stirrer speed. Other composites were deposited at various substrate of brass, steel (HSS) and galvanic metal substrates at fixed electrodeposition current and stirrer speed. The crystal structure of composites was characterized by using XRD spectrum analysis and the corrosion test was performed by using mass loss method. The results show that crystalization and the corrosion rate of the composites is better at high electrodeposition current and low stirrer speed. It shows that the crystalization and corrosion rate of the coating on brass substrate are better than others.

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Optical and Photoluminescence Properties of Dy3+ doped ZnO-Al2O3-B2O3 Glasses for UV Sensor Application

Mitra Djamal, Lia Yuliantini, Rahmat Hidayat, Kitipun Boonin, Patarawagee Yasaka and Jakrapong Kaewkhao

Journal of Technology and Social Science, Vol.1, No.2, pp.62-68, 2017.

Abstract: The importance of product authenticity becomes more attention due to the increase of counterfeiting medicines, beverages, and foods. One of solutions of the problem is by inserting invisible bar code UV sensor in the product to keep the authentication. The bar code will show under UV light and emit visible light. The present UV sensor was developed by melt-quenching method with composition 10ZnO:10Al2O3:20BaO: (60-x)B2O3:xDy2O3 where x is 0.1, 0.3, 0.5, 1.0, 1.5, 2.0, and 2.5 mol%. Glass medium doped rare earth is chosen as host material of UV sensor due to the strengthened of light emission and reliable detection. The characterization of physical and optical of the glass medium such as density, molar volume, absorption, excitation, and emission spectra were analysed. The highest peak of absorption intensity occurs at the wavelength of 1266 nm. From emission spectra, prepared glass medium emitted 482, 575, 664, and 752 nm wavelength when excited by 350 nm wavelength. The highest intensity of emission spectra was shown in 0.5 mol% of Dy3+ ion concentration. The developed glass medium doped Dy3+ is suitable candidate for application of UV sensor that is excited by 297, 325, 350, 364, 387, 426, 452, and 471 nm wavelength.

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Public Perception of Public Service Announcement (PSA) on Transportation Safety Awareness through Television in Jakarta

Endang Widjajanti

Journal of Technology and Social Science, Vol.1, No.2, pp.69-76, 2017.

Abstract: One form of awareness of transportation safety conducted by the Ministry of transportation of the Republic of Indonesia is the dissemination through television, known as public service announcements (PSA). This study is part of the activities of the Ministry of transportation of the Republic of Indonesia in getting a response and perceptions to PSA that aired through television in Jakarta.  Method of the survey is an interview with questionnaires. The results showed that only 28%-56% of respondents who viewed five PSA that aired. About 40%-50% of respondents said PSA is interesting. The reason why the PSA doesn't appeal is the duration too short and boring. In order to be understood and respected by the community, the majority of respondents suggest to increase the duration of the PSA and PSA broadcast continuously.

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Trans Semarang Bus Service Analysis for Monitoring and Passenger Information System

Mudjiastuti Handajani

Journal of Technology and Social Science, Vol.1, No.2, pp.77-83, 2017.

Abstract: Semarang Smart Transportation Program is creating the city transportation system which are reliable, environmentally sound, safe, comfortable, well-organized and modern management. Nowadays, Trans Semarang Bus always came in uncertain times. The purpose of this study was analyzing Trans Semarang Bus performance which able to increase the better city transportation system in the future especially developed country like Indonesia. Monitoring and Passenger Information System were able to inform buses depart and arrival in the real time. Research methodology in this study used qualitative and quantitative technique. The result for this study was long route 26.75 km; average speed 14 km/ hour; time calculation 2.1 hours; waiting time 10 minutes, headway 20 minutes, bus stop distance 300 meters. Many people in Semarang are expected the on time city buses. Data will be entered into Monitoring System (MS) and Passenger Information System (PIS). MS and PIS will give accurate information and go to better city transportation system.

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Development of a Low Cost Mobile Volcano Early Warning System

Mitra Djamal, Maria Evita, Bernd Zimanowski and Klaus Schilling

Journal of Technology and Social Science, Vol.1, No.2, pp.84-91, 2017.

Abstract: A new early warning system has been developed for Indonesian volcano, which is in the second place for the most dated eruption after Japan. This low cost system consists of Wireless Sensor Network (WSN) for sensing, processing, distributing and transmitting the data; satellite technology for remote sensing data of the volcano; and mobile robot for replacing a died sensor node in emergency situation. Not only for normal condition when only small events happen, but the system is also robust to a hazard erupting volcano environment to acquire real-time data in high-fidelity operation and manages both the power and bandwidth efficiently in the same time. Simulation and laboratory experimental result show that the system consumed lower energy and utilized better the bandwidth than the current existing system. Furthermore, the mobile robot has been successfully arrived at the desired location for broken node substitution with no human involvement in a toxic dangerous area.

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