The demands the automotive gear designer has to considerduring the gear design process have changed. To design a gearthat will not fail is still a challenging task, but now lownoise is also a main objective. Both customers and legalregulations demand noise reduction of gears. Moreover, thequality of the product is more in focus than ever before. Inaddition, the gear design process itself must be inexpensiveand quick. One can say that the gear designer faces a newdesign environment. The objective of this thesis is tocontribute to the answer to some of the questions raised inthis new design environment. In order to respond to the new design situation, the geardesigner must consider new phenomena of gears that werepreviously not a matter of concern. One such phenomenon is anew gear failure type, Tooth Interior Fatigue Fracture (TIFF).As the gear teeth are made more slender in an attempt to reducethe stiffness variation during the mesh cycle, therebypotentially reducing the noise, the risk of TIFF is increased.The phenomenon of TIFF is explored in detail (paper III-VI)through fractographic analysis, numerical crack initiationanalysis using FEM, determination of residual stress by meansof neutron diffraction measurements, testing for determiningmaterial fatigue properties, fracture mechanical FE-analysis,sensitivity analysis and the development of an engineeringdesign method. The main findings of the analysis of TIFF arethat TIFF cracks initiate in the tooth interior, TIFF occursmainly in case hardened idlers, the fracture surface has acharacteristic plateau at approximately the mid-height of thetooth and the risk of TIFF is more pronounced in slender gearteeth. Along with the more optimised gear design, there is atendency for the gear to be less robust. Low robustness, i.e.,great variation in performance of the product, implies a highincidence of rejects, malfunction and/or bad-will, all of whichmay have a negative effect on company earnings. As the use ofoptimisation decreases the safety margins, greater attentionhas to be paid to guaranteeing the products' robustness.Moreover, in order to be cost-effective, the qualities of thegear must be verified early in the design process, implying anextended use of simulations. In this thesis, two robustnessanalyses are presented in which the analysing tool issimulation. The first one considers robust tooth root bendingfatigue strength as the gear is exposed to mounting errors, thesecond one considers robust noise characteristics of a gearexposed to manufacturing errors, varying torque and wear. Bothof these case studies address the problem of robustness ofgears and demonstrate how it can be estimated by use ofsimulations. The main result from the former robustnessanalysis is that wide gears are more sensitive to mountingerrors, while the latter analysis showed that to achieve robustnoise characteristics of a gear it should have large helixangles, and some profile- and lead crowning should beintroduced. The transverse contact ratio is a trade-off factorin the sense that both low average noise levels and low scatterin noise due to perturbations cannot be achieved. <b>Keywords</b>: robust design, Taguchi method, gear, idler,simulations, Finite Element Method, Tooth Interior FatigueFracture, TIFF

The principal objective of this study was to compare the results of a proposed method based upon the response surface model to the Taguchi method. To modify the Taguchi method, the proposed model was developed to encompass the following objectives. The first, with the exception of the Taguchi inner array, was obtain optimal design variable settings with minimum variations, at the same time achieving the target value of the nominal-the best performance quality characteristics. The second was to eliminate the need for the use of a noise matrix (that is, the Taguchi outer array), resulting in the significant reduction of the number of experimental runs required to implement the model. The final objective was to provide a method whereby signal-tonoise ratios could be eliminated as performance statistics. To implement the proposed method, a central composite design (CCD) experiment was selected as a second-order response surface design for the estimation of mean response functions. A Taylor's series expansion was applied to obtain estimated variance expressions for a fitted second-order model. Performance measures, including mean squared error, bias and variance, were obtained by simulations at optimal settings. Nine test problems were developed to test the accuracy of the proposed CCD method. Statistical comparisons of the proposed method to the Taguchi method were performed. Experimental results indicated that the proposed response surface model can be used to provide significant improvement in product quality. Moreover, by the reduction of the number of experimental runs required for use of the Taguchi method, lower cost process design can be achieved by use of the CCD method. / Graduation date: 1993

No description available.

The backlight module is usually used to increase visual angle and brightness of liquid crystal display (LCD). Thus, the design and fabrication of optical films, including light guide plate, diffuser film, and brightness enhancement film (BEF), are critical factors to decide the optical efficiency in a backlight module. In order to improve the optical efficiency for power-saved display with competitiveness, this study presents a new fabrication process combining precision machining, lithography, and hot-embossing techniques to form a two-side-patterned optical film. One side of the optical film is micro triangular-pyramidal array (MTPA) and the other is micro spherical lens array(MSLA). First, the Taguchi method is applied to design the optimal microstructure configuration by the assistance of the optical software, FRED. Second, a tungsten (W) steel mold (as the mold to hot emboss MTPA) is manufactured by precision machining including optical projection grinding, lapping, and polishing processes. Meanwhile, a nickel-cobalt (Ni-Co) mold (as the mold to hot emboss MSLA) is fabricated by electroplating process. Then, polydimethylsiloxane (PDMS) is used to replicate the MTPA and MSLA patterns, on W and Ni-Co metal molds, respectively, and the replicated PDMS films are used as the molds to form a two-side-patterned optical film. In addition, the optical property such as luminance is measured by photo research 650 (PR 650) to evidence the optical function of the two-side-patterned optical film. From the experimental results, both brightness and uniformity can be improved by this film;thus, optical efficiency is successfully increased in this study.

Fairy shrimp is an anostraca plankton which is raised for watching and scientific study. In recent year, due to the large requirement of fairy shrimp in the market, to increase the hatching rate of fairy shrimp is an important topic. It is found that when an Artemia Cysts hatched by light, the pigment absorption spectra in the Cysts match with the optical wavelength of the experimental incubators. Furthermore, the effect of ultrasound can stimulate the growth or activation of the fairy shrimp, when the ultrasonic parameters of frequency, intensity, exposure time and exposure period are properly controlled in the hatching experiments. This thesis is then focusing on the biological activities to increase the hatching rate of fairy shrimp by light and ultrasound exposure. This work investigates the light effect on the hatching experiment using different wavelength and intensity of LED light; in addition, Cysts is exposed to ultrasound by ultrasonic cleaner and transducer. The resonant frequency of the Cysts is obtained from Rayleig ¡VPlesset bubble activation formula. The radiation of the resonant and non-resonant regions during the hatching experiments are then set up by this resonant frequency for comparison. Finally, according to the experimental results, the correlations of hatching rate with light wavelength, light intensity, resonant frequency and ultrasound intensity are studied by Taguchi Method to understand the play role of the light and ultrasound. The research results show that the hatching rate is 25 % by lamp irradiation, and the maximum hatching rate is 42.5 % by blue light in the light experiment. In ultrasound experiment, the highest incubate percentage, 35 %, is obtained by ultrasound frequency 0.25 MHz and ultrasound intensity 39.2 mW/cm2. In the confirmed test, the blue light plus ultrasound frequency of 0.25 MHz plus ultrasound intensity of 30.9 mW/cm2 can let the incubate percentage up to 48.3%. This is the highest incubate percentage one can get from these experiments. Finally, the results of Taguchi analysis shows that the Confidence level of light affecting the hatching rate is 100%; thus, light source is the most critical factor to affect the hatching procedure. The results of this research can be referred by an endangered species or high economic value of species to increase the rate of hitching.

Due to the improvement of luminous efficiency, LED has been applied in general lighting nowadays. However, the efficacy and life of high power LED lamps are degraded for the problem of overheat temperature of the chips. In accordance with the above reason, the thermal management has been important in LED application. The thesis aims to analyze the thermal problem of high power LED lamp by FEM. In the beginning, we analyzed the temperature curves and thermal stress curves of chips by changing the thickness of AuSn solder in 4 structures. According to the results, the better thickness range and structures were chosen. In the second step, the effect of different sizes of a vapor chamber on the different thermal conductivities of lamp system was discussed. Finally, we orthogonalized all the designed parameters by Taguchi orthogonal array method, and then found the optimal design by comparing the results with the initial analyses. In this study, we proposed a solution to improve the quality characteristics of LED lamp by Taguchi method. So the effect of each control factors on the performance was able to be determined. For different features of demand, the present study is helpful to achieve the ideal design in manufacturing. Key words: FEM, high power LED lamps, Taguchi orthogonal array method

The resources on earth are limited; thus, the demand for energy, goods and materials is surging because of the growth of the advanced technology and population. The issues of using the resources effectively and changing them into a useful energy are then important. Taiwan creates a vast amount of agricultural waste every year. The traditional way of eliminating the agricultural waste would be burned and buried. However, it is not only the agricultural waste cannot be reused and recycled, but also the problem of air pollution occurred. The objectives of this thesis are thus to transfer the agricultural waste into a useful energy. This study contents two parts. The first part changes the agricultural waste into sugar. The agricultural waste is full of wood fiber and can be transformed to sugar by a microorganism method. A cane which is a common agricultural waste is used; the wood fiber in cane will be added to the thermostable cellulolytic bacterial Geobacillus thermoleovorans T4 isolated from sugar refinery wastewater in southern Taiwan. T4 can convert wood fiber into sugar. Experimental results showed that the rate of reducing sugar is 13.77%. The second part studies the biological hydrogen production by Clostridium acetobutylicum ATCC 824, and the sugar will be added into the process. Also, this study uses ultrasonic treatment in the biological hydrogen production and calculates the natural frequency of ATCC 824. The experiment is designed using the Taguchi method for increasing hydrogen production, hydrogen production rate and hydrogen production efficiency by using an ultrasonic treatment to treat C. acetobutylicum ATCC 824. It is showed that the best combination is temperature 37¢XC, ultrasonic frequency 0.5 MHz, ultrasonic intensity 136 mW/cm2, exposure time 10 s, pH 7.5 and bacterial concentration 20%. This study can apply in bio-energy and fermentation food producing.

Wire bonding has been used in integrated circuit packaging for many decades because of its high reliability and performance. The most common metal used has been gold, but with the surge in commodity prices of gold in recent years, copper wire is now used to altered gold wire for cost saving. Many challenges have to be solved to meet its application requirement; coating is one of the applications. In this study, a 3D coated copper wire and coated Al pad is built by finite element method to simulate ultrasonic bonding and thermosonic bonding. To consider the effect of coated material to stress and strain field on ultrasonic bonding and the effect of coated material to temperature field on thermosonic bonding. Then use the Taguchi experiment method to discuss the effect on Cu-Ball and Al pad under different coated material and thickness combination. The results show that with coated material on Al pad or copper wire could reduce more than 48% of effective plastic strain after the bonding process, it obviously reduce the Al splash phenomenon in copper wire bonding. But the coated material such like palladium and nickel which have lower thermal conductivity would resist the heat transfer. And the Taguchi experiment method shows that the most effective way to reduce the effective stress during impact stage and ultrasonic vibration stage is to increase the thickness of palladium and nickel respectively, and when the thickness of coated material Au reached 0.01£gm could increase the temperature of Cu-Ball and Al pad mostly.

(La0.67Sr0.33MnO3)£»(SrO), LSMO214(n=1) in short, is 2-D magnetic insulator with a structure very similar to the 3D La0.67Sr0.33MnO3 and La0.67Ca0.33MnO3, 113(n=1) in short, which consists of superstructure of a subsequent magnetic layers and insulating layers. Forming a single 214 phase bulk is not easy, a mix phase of 2<n<¡Û compounds is usually seen. In this project, our goal is to search the best growth condition by the traditional method by varying one growth parameter at a time and by the famous Taguchi methods which is based on the statistics and is proved in many systems a best way in studying the association between the film properties and the control factors. First part of this project, we change one growth condition at a time and find the film quality related with the growth condition. Second, we use ¡§Taguchi method¡¨ as bases to form a perpendicular table in which various growth conditions and levels are set. According the table, the number of experiments is limited down to nine. All of the films are examined by structure, electric and magnetic properties to formed the quality data base for films. The traditional method concludes that the higher growth temperature, lower total chamber pressure and high partial pressure ratio of Ar and Oxygen are the corrected way approaching to the single phase, 214, films. However, the result from Taguchi method is contradict to the tradition method, in which the high growth temperature, high total chamber pressure, low partial pressure ratio of Ar and oxygen and the medium RF forward power can approach to growth the single 214 phase film. All films consists mix phases of higher n. This may imply that the growth window for LSMO 214 is relative narrow that we did not set our condition right in that opening.

Taguchi methods is also called quality engineering. It is a systematic methodology for product design(modify) and process design(improvement) with the most of saving cost and time, in order to satisfy customer requirement. Taguchi¡¦s parameter design is also known as robust design, which has the merits of low cost and high efficiency, and can achieve the activities of product quality design, management and improvement, consequently to reinforce the competitive ability of business. It is a worthy research course to study how to effectively apply parameter design, to shorten time spending on research, early to promote product having low cost and high quality on sale and to reinforce competitive advantage. However, the parameter design optimization problems are difficult in practical application owing to (1)complex and nonlinear relationships exist among the system¡¦s inputs, outputs and parameters and (2)interactions may occur among parameters. (3)In Taguchi¡¦s two-phase optimization procedure, the adjustment factor cannot be guaranteed to exist in practice. (4)For some reasons, the data may become lost or were never available. For these incomplete data, the Taguchi¡¦s method cannot treat them well. Neural networks have learning capacity fault tolerance and model-free characteristics. These characteristics support the neural networks as a competitive tool in processing multivariable input-output implementation. The successful field including diagnostics, robotics, scheduling, decision-marking, predicition, etc. In the process of searching optimization, genetic algorithm can avoid local optimization. So that it may enhance the possibility of global optimization. This study had drawn out the key parameters from the spheroidizing theory, and L18, L9 orthogonal experimental array were applied to determine the optimal operation parameters by Signal/Noise analysis. The conclusions are summarized as follows: 1. The spheroidizing of AISI 3130 used to be the highest unqualified product, and required for the second annealing treatment. The operational record before improvement showed 83 tons of the 3130 steel were required for the second treatment. The optimal operation parameters had been defined by L18(61¡Ñ35) orthogonal experimental array. The control parameters of the annealing temperature was at B2