Engineering Commons^™

Bs News November/December

Building Services Engineering

No abstract provided.

Space-Time Least-Squares Finite-Element Method For Shallow-Water Equations, Shin-Jye Liang, Ying-Chih Chen

Journal of Marine Science and Technology–Taiwan

In this paper, a space-time least-squares finite-element method for the 2D nonlinear shallow-water equations (SWE) is developed. The method can easily handle complex geometry, bed slope (source term), and radiation boundary condition without any special treatment. Other advantages of the method include: high order approximations in space and time can easily be employed, no upwind scheme is needed, as well as the resulting system equations is symmetric and positivedefinite, therefore, can be solved efficiently with the pre-conditioned conjugate gradient method. The model is applied to several benchmark tests, including standing wave in a flat closed basin, propagation of sinusoidal wave …

Transient Response Of Long Bubbles In Volatile Organic Compounds, Cheng-Hsing Hsu, Ching-Chuan Chang, Chia-Chuan Kuo, Kuang-Yuan Kung

Journal of Marine Science and Technology–Taiwan

A mass flow controller (MFC) was used to control the injection gas amount into volatile organic compounds (VOCs), each having a different evaporation rate, within straight tubes. As the moving velocities of the air bubbles within the straight tube had changed, a specific transient response occurred. The transient shape was a mushroom bubbles. From the experiment results, as the evaporation rate of VOCs ≧ 1, mushroom bubbles occur as the Reynolds number (Re) of the moving air bubbles reach a certain region. Moreover, the shapes mushroom bubbles were more apparent when volatility of the solvent was higher. As VOCs evaporation …

Reconsideration For A Study Of The Effect Of Chloride Binding On Service Life Predictions, Ming-Te Liang, Ran Huang, Hao-Yuan Jheng

Journal of Marine Science and Technology–Taiwan

The major purpose of this paper is to use Kirchhoff's transformation associated with Laplace's transformation methods to obtain the analytical solution of the modified Fick's second law of nonlinear diffusion equation with initial and boundary conditions provided by Martín-Pérez et al. [A study of the effect of chloride binding on service life predictions. Cement and Concrete Research 2000; 30 (8): 1215-1223]. Based on experimented data and four kinds of chloride binding isotherm, i.e., no, linear, Langmuir, and Freundlich binding, results of free and total chloride concentration profiles calculated from the analytical solution are presented for a concrete structure suffered from …

The Modified Collocation Trefftz Method And Laplacian Decomposition For Solving Two-Dimensional Stokes Problems, Chia-Ming Fan, Hong-Huei Li, Chung-Lun Kuo

Journal of Marine Science and Technology–Taiwan

In this paper, the two-dimensional Stokes problem is analyzed by the modified collocation Trefftz method (MCTM) and the Laplacian decomposition. The coupled Stokes equations are converted to three Laplace equations by utilizing the Laplacian decomposition and then the boundary-type meshless MCTM is adopted to solve the resultant Laplace equations. The MCTM, free from mesh and numerical quadrature, is derived from the conventional Trefftz method by considering the characteristic length of the domain, which stabilize the numerical scheme and obtain highly accurate results. Besides, the solutions are expressed as the linear combination of T-complete functions and the velocity as well as …

Overcoming The Negative Frequencies - Instantaneous Frequency And Amplitude Estimation Using Osculating Circle Method, Ming-Kuang Hsu, Jiun-Chyuan Sheu, Cesar Hsue

Journal of Marine Science and Technology–Taiwan

There are many methods able to extract the instantaneous frequencies from a time series for practical applications. Gabor's method is one of the most popular and simple methods. For wide band time series, Gabor's method may produce negative frequencies. The limitation of Gabor's method is that, in order to avoid resulting with negative frequencies, it can only be applied to time series with mono component and near zero mean. In this paper, a new method that does not generate negative frequencies, the Osculating Circle (OC) Method, is presented. The OC method is based on Gabor's method but with modified unwrapped …

Long-Term Predictive Value Interval With The Fuzzy Time Series, Ming-Tao Chou

Journal of Marine Science and Technology–Taiwan

This paper presents a new mathematical method to construct a fuzzy time series model of a system where the fuzzy support and interval values are used. This paper further presents an improved fuzzy time series model with a long-term predictive value interval and shows that the proposed definition can be used for long-term forecasting. The enrollment data of the University of Alabama (adopted by Song and Chissom, 1993) are used to demonstrate the proposed forecast model.

Selecting Ports And Terminal Operators - An Application Of Pso, Tzay-An Shiau, Li-Mei Lin, Ding-Hsun Hsiao

Journal of Marine Science and Technology–Taiwan

Past literature has mostly discussed port selection. However, within a given region, any port which meets a carrier’s threshold conditions is eligible for consideration, and a terminal operator at any of these ports is a candidate for entering into a contract with the carrier. The choice is not restricted to terminal operators at a single given port. Thus the choice of terminal operator between ports within a given region is an important issue in the decision-making process and has rarely been addressed in the literature. The main purpose of this paper is to examine a situation in which all ports …

Numerical Assessment Of A Venting System With Multi-Chamber Mufflers By Ga Method, Min-Chie Chiu, Ying-Chun Chang

Journal of Marine Science and Technology–Taiwan

Recently, research on new techniques of single-chamber perforated silencers has been addressed. However, the research work on shape optimization of multi-chamber silencers within a compact volume is rare. Work on the maximal allowable back pressure of mufflers has also been neglected. Therefore, the main purpose of this paper is to analyze the sound transmission loss (STL) of a space-constrained multi-chamber muffler and to optimize the best design shape under a specified pressure drop. In this paper, both the generalized decoupling technique and plane wave theory used to solve the coupled acoustical problem of multi-chamber perforated mufflers are presented. The four-pole …

Fuzzy Control For Input Constrained Passive Affine Takagi-Sugeno Fuzzy Models: An Application To Truck-Trailer System, Wen-Jer Chang, Cheung-Chieh Ku, Chien-Hsun Huang

Journal of Marine Science and Technology–Taiwan

This paper describes a design of fuzzy controller for the input constrained discrete nonlinear passive systems via affine Takagi-Sugeno (T-S) fuzzy models. The stability conditions are derived based on Lyapunov and passive theories for the closed-loop system. The fuzzy controller design is accomplished by using the concept of Parallel Distribution Compensation (PDC). According to the proposed fuzzy control approach, the controlled system can achieve passive property and the input constraint, simultaneously. The Iterative Linear Matrix Inequality (ILMI) algorithm is applied in this paper to find the feasible solutions for the proposed fuzzy controller design approach. At last, a numerical simulation …

Experimental Study On The Flow Characteristics For Wind Over A Two-Dimensional Upwind Slope Escarpment, Ben-Jue Tsai, Bao-Shi Shiau

Journal of Marine Science and Technology–Taiwan

In this present study, wind tunnel experiments were conducted to measure the flow and turbulence characteristics for wind over an upwind slope of 15° escarpment. The mean wind speed and turbulence statistics, such as turbulence intensity, Reynolds stress, and wind power spectrum are investigated. Results indicate that wind speed-up phenomenon (increase of speed) occurred significantly around the tip of the upwind slope. The turbulence intensity decreases gradually as the wind flows from the toe of upwind slope to the tip of upwind slope. The wind power spectra for several sites along the upwind slope and top surface of escarpment at …

Comparison Of Computational And Experimental Aerodynamics: Results For A Wmu Solar Car Model, Yang Yang, William W. Liou

The Hilltop Review

Three-dimensional numerical simulations using FLUENT [1] were performed to model the airflow over the Sunseeker, an award-winning solar car that was designed and built at Western Michigan University. Converged numerical solutions on three different grids are reported and compared with the available experimental data, which include the lift and the drag coefficients. Also reported are the results obtained by using the second-order upwinding discretization on one of the grids. The comparison shows that the computed lift coefficients agree well with the experimental data for all the three grids and the different orders of numerical methods, indicating that the pressure field …

Evaluation Of Dye And Pigment Based Ink Jet Ink Sets, Veronika Chovancova

The Hilltop Review

The development of high performance inkjet printers and inks is advancing rapidly. Manufacturers seem to introduce their new technology inks to the market on an almost daily basis. Chemists in ink laboratories are still fighting with the issue of combining a wide gamut of dye-based inks with the lightfast and weather resistance qualities of pigment-based inks into new-age ink formulations.

Three different inkjet printers and inks were investigated in this work: the Epson Stylus® Pro 5000, using a dye-based ink set, the Epson Stylus® Pro 5500, employing Archival ink technology, and the Epson Stylus® Photo 2200, with 7-color UltraChrome™ inks. …

Adaptive Control In Swarm Robotic Systems, Hanyi Dai

The Hilltop Review

Inspired by the collective behavior observed in natural insects, swarm robotics is a new approach in designing control algorithms for a large group of robots performing a certain task. In such robotic systems, an individual robot with only limited capabilities in terms of sensing, computation, and communication can adapt its own behavior so that a desired collective behavior emerges from the local interactions among robots and between robots and the environment. Swarm robotics has been the focus of increased attention recently because of the beneficial features demonstrated in such systems, such as higher group efficiency, robustness against the failures of …

The Study Of Ink Pigment Dispersion Parameters, Lokendra Pal, Paul D. Fleming Iii

The Hilltop Review

The purpose of this study was to investigate the influence of rotation speed and milling time on the pigment dispersion quality. The information can be used to obtain a standard laboratory condition at which a wide range of pigments may be dispersed to formulate water-based rotogravure inks. The influence of pigment concentration and shear forces on the pigment dispersion were also studied.

The procedure consisted of dispersing the pigment using a laboratory Dispermat® SL bead mill at various milling times with two different rotation speeds and measuring the particle size and particle size distribution of the milled samples. The pigment …

Bs News September/October

Building Services Engineering

No abstract provided.

Study On Residual Powders Of Lithium-Ion Batteries With Different Voltages After Explosion, He Li, Zhi-Kui Chen, Ji-Na Cao, Guang-Chuan Liang

Journal of Electrochemistry

The residual powders of lithium-ion batteries at different voltages after explosion were obtained by using the battery impact testing machine. And these powders have been investigated by weighing, water solution and X-ray diffraction (XRD). The results showed that the integrity status of copper current collector and weight of residual powders decreased gradually with increasing of battery voltage, rising of burning temperature and releasing of burning duration time. The residual powders could be separated to insoluble powders and soluble powders by the water solution. The proportion of the insoluble powders is more (about 90%) including C, Co and CoO, while the …

Electrochemical Performance Of Tin Dioxide/Carbon Xerogel Composites As Anode Materials For Lithium-Ion Batteries, Xiao-Jing Liu, Lin-Lin Qin, Yi-Ning Shi, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

The tin dioxide/carbon xerogel composites were synthesized by using vacuum infiltration method. Structural characterization and morphology of the composites were investigated by using XRD, TEM and SEM techniques. BET test was performed to determine the pore size distributions of carbon xerogels and the composites. The results showed that the nano-sized SnO₂ particles (5~10 nm) were encapsulated in the pores of carbon xerogels. During the electrochemical tests the SnO₂ in the composites exhibited capacity retention of 61.9% after 100 cycles of charge-discharge tests at 100 mA/g.

Study On The Fluorescent Carbon Nanodots With Electrochemical Methods, Bao-Ping Qi, Yan-Min Long, Lei Bao, Cui Liu, Zhi-Ling Zhang, Dai-Wen Pang

Journal of Electrochemistry

Carbon nanodots are a new class of fluorescent nanoparticles with a carbon-based core, which possess wavelength-tunable luminescence, high photostability, resistance to photobleaching, water-solubility, and ease of bioconjugation. Owing to their attractive merits, carbon nanodots like other carbon nanomaterials such as fullerene, carbon nanotubes and graphene, have attracted much attention. In addition, carbon nanodots can be inexpensively produced by electrochemical methods with simple post-processing under mild conditions. Electrochemical approaches have unique advantages in the analysis of surface structures and luminescence mechanism of materials. In this review, recent advances in electrochemical methods used for the synthesis and luminescence mechanism of fluorescent carbon …

Effects Of Graphene On Electrochemical Behaviors Of Ni(Oh)2 As Supercapacitor Material, Zhen-Zhen Zhao, Wen-Bin Ni, Neng-Yue Gao, Hong-Bo Wang, Jian-Wei Zhao

Journal of Electrochemistry

The enhanced electrochemical properties of Ni(OH)₂ by the oxidation defected graphene were studied by both experimental method and theoretical calculation. The composite material of nano-Ni(OH)₂/graphene was prepared by potentiostatic deposition on the graphene substrate. Observed by TEM, the Ni(OH)₂ nanoparticles were well dispersed on the graphene substrate with the diameter of 5.0±0.5 nm. The capacitance of the system measured by the electrochemical test was 1928 F·g^-1. As indicated by the theoretical calculations, the composite material becomes conductive since Ni(OH)₂ is combined with surface functional groups of the graphene through the strong chemical interaction. …

Photogenerated Cathodic Protection Of Stainless Steel, Cheng-Gang Lin, Ze-Quan Lin, Jing Li, Chang-Jian Lin

Journal of Electrochemistry

A highly ordered Co-doped TiO₂ nanotube layers were fabricated by potentiostatic anodization of pure titanium in fluorinated electrolyte solutions followed by ion-exchange method. The structure and composition of the as-prepared Co-doped TiO₂ nanotube layers were characterized by SEM, XRD, UV-Vis, and XPS. The effects of dopant content on the morphologies, structural and photochemical properties of the TiO₂ nanotube arrays were investigated. The performances of photogenerated cathodic protection and the photoelectrochemical response for the Co-doped TiO₂ nanotube arrays under illumination and dark conditions were evaluated through the electrochemical measurements. The Co-doped TiO₂ nanotubes showed a stronger …

Electrelectrochemical Performances Of C-Coating And Co-Doping Lifepo4, Ying Bai, Jue-Ming Yang, Chun-Bo Qing, Wei-Feng Zhang

Journal of Electrochemistry

Phospho-olivine LiFePO₄ cathode materials were prepared by hydrothermal reaction at 200 ^oC. Sucrose was added as C-coating resource and Co was doped into the crystal lattice of LiFePO₄. In order to investigate the improvements in the electrochemical properties of Co-doped LiFePO₄, three samples, LiFePO₄, C-coated LiFePO₄ and C-coating-Co-doped LiFePO₄, were synthesized under the same preparation conditions. Charge/discharge studies reveal that the Co-doped LiFePO₄/C composite annealed at 400 ^oC exhibits marked improvement of specific capacity by diminishing the particle sizes and enhancement in the degree of crystallinity. …

Simultaneous Determination Of Dopamine(Da)And Epinephrine (Ep) At Ca/Gc Electrode, Wang Ren, Ying Zhang, Min-Jiao Li

Journal of Electrochemistry

The citric acid modified glassy carbon electrode (CA/GC) was prepared by potentiostatic technique and was used for detections of dopamine (DA), epinephrine (EP), and their mixtures by differential pulse voltammetry (DPV). The modified electrode shows the enhanced sensitivity and excellent electrochemical discrimination to DA and EP. The cathodic potential difference between DA and EP was about 380 mV, while no cathodic reduction of ascorbic acid (AA) was observed because the oxidation of AA is an irreversible reaction at the sensor. As a result, DA and EP could be determined simultaneously with the interferences of high concentrations of AA being eliminated. …

Study On The Electrochemical Behaviors Of Gc Electrode Modified With Carbon Nanotube-Polyelectrolytes And Its Application For Rutin Detection, Liang Hua, Xia-Qin Wu, Rong Wang

Journal of Electrochemistry

The electrochemical behaviors of rutin and ascorbic acid at single-wall carbon nanotube and polyelectrolytes (dimethyl-diallylammonium chloride, PDDA) film modified glassy carbon electrode was investigated. The cyclic voltammetric results showed that electron transfer of rutin at PDDA/SWCNTs/GC modified electrode is an adsorption-controlled process. The separation of oxidation peak potentials of rutin and ascorbic acid was more than 200 mV. The rutin concentration in the presence of AA were detected by differential pulse voltammetry (DPV). The experimental results indicated that the PDDA/SWCNTs/GC modified electrode can be used for the detection of rutin in the presence of high concentration of AA. The DPV …

Brief Introduction To Metal Corrosion And Protection, Hou-Yi Ma, Cong-Ying Cui, Ting Chen

Journal of Electrochemistry

This paper explains why corrosion processes are usually electrochemical in nature, describes the significance of electrochemical kinetic parameters of corrosion process, and briefly introduces the principles of corrosion protection, the most common corrosion protection methods and some special application of corrosion processes.

Surface Diffusion Of Adsorptive Species On Gold Nanoelectrodes, Bao-Fa Su, Wei Wang, Dong-Ping Zhan, Bin Ren, Zhong-Qun Tian

Journal of Electrochemistry

Gold nanoelectrodes were prepared successfully by a programmed laser puller. The Faraday adsorptions of oxygen and iodine, and the underpotential deposition of lead on the gold nanoelectrodes were investigated. The results showed that the active areas of nanoelectrodes were dramatically higher than their appearant geometry areas, which is caused by the surface diffusion of adsorptive species from the nanoscale gold/electrolyte interface to the adjacent gold surface.

Synthesis Of Limnpo4/C Used As Cathode Material For Lithium Ion Batteries, Xin Yang, Xue-Wu Liu, Gui-Chang Liu, Zhi-Cong Shi, Xin Li, Guo-Hua Chen

Journal of Electrochemistry

The LiMnPO₄/C composites were prepared using a solid-state reaction with addition of the resorcinol formaldehyde resin as the carbon source. The effects of reaction temperature and time on the crystal structure, morphology and electrochemical properties of the LiMnPO₄/C composites were investigated. The results show that the best performance was achieved with the LiMnPO₄/C composites synthesized at 600 ^oC for 12 h which had the particle sizes about 100~200 nm. The initial discharge capacities were 121.6 mAh·g^-1 at 0.02C, 110 mAh·g^-1 at 0.1C and more than 60 mAh·g^-1 at 1C. An …

Synthesis And Electrochemical Behaviors Of Li2Coxmn1-XSio4 As A Cathode Material For Lithium-Ion Batteries, Lin Wang, Dong-Ping Lv, Yong Yang

Journal of Electrochemistry

We have successfully synthesized Li₂Co_xMn_1-xSiO₄/C (x=0, 0.1, 0.3, 0.5, 1)/C composites using hydrothermal assisted sol-gel process and ball-milling method. The results of X-ray diffraction show that the solid solutions of Li₂Co_xMn_1-xSiO₄ can be achieved when x≤0.3. The initial capacities increase from 70 mAh·g^-1 of Li₂MnSiO₄/C to 105 mAh·g^-1 of Li₂Co_0.3Mn_0.7SiO₄/C. Cyclic Voltammetry (CV) curves show that the replacement of Mn with Co can reduce the electrochemical polarization, making the insertion-extraction reaction …

Corrosion Characteristics Of Galvanized Flat Steel For Power Grounding In Nacl Solution Medium, Yong Li, Gao-Lin Wu, Bang-Fei Deng, Ping Yang, Xue-Ming Li, Qing-Bin Zong

Journal of Electrochemistry

The corrosion behavior of power grounding galvanized flat steel was studied by polarization measurement, electrochemical impedance spectroscopy and neutral salt spray test in 5% NaCl solutions. The surface morphologies of galvanized coating and structural properties of corrosion products were observed with scanning electron microscope and X-ray diffraction spectrometer, respectively. Results showed that under the temperatures of 20~60℃, the corrosion currents of galvanized flat steel increased with the temperature rising. The corrosion rate at 60℃ was 0.8408 mA·cm^-2, which is 2.9 times larger than that at 20℃. The corrosion rate dropped after reaching the maximal value of 1.95 mg·cm …

Development Of Dehydrogenase-Based Bioanode Using Poly(Phenosafranin)-Functionalized Swcnt Nanocomposites And Its Application To Ethanol Biosensor, S. Saleh Farhana, Okajima Takeyoshi, Lanqun Mao, Takeo Ohsaka

Journal of Electrochemistry

A New type of dehydrogenase-based amperometric ethanol biosensor was constructed using alcohol dehydrogenase (ADH) which was immobilized on the edge-plane pyrolytic graphite (EPPG) electrode modified with poly(phenosafranin)-functionalized single-walled carbon nanotube (PPS-SWCNT). The PPS-SWCNT modified EPPG electrode was prepared by electropolymerization of phenosafranin on the EPPG electrode which was previously coated with SWCNT. The performance of the ADH/PPS-SWCNT/EPPG electrode was evaluated using cyclic voltammetry and amperometry in the presence of ethanol. The fabricated ethanol biosensor provided a reasonable sensitivity of 2.0 μA cm–2 mM–1 and a low detection limit (36 μM) for the electrocatalytic oxidation of ethanol with a linear concentration …