In this study, we proposed an advanced motion analysis method of the upper limbs including clavicle using inertial sensor. To estimate the posture of the upper limbs, inertial sensor system which is composed of a tri-axial accelerometer, a tri-axial gyroscope and a tri-axial geomagnetic sensor is developed. Two inertial sensors are attached to the right and left clavicle to observe the motion between sternoclavicular joint and acromioclavicular joint, and totally seven sensors are used to estimate the posture of upper limbs. The posture of each body part is obtained by applying extended Kalman filter during the slow motion and by integration of angular velocity during rapid movement. Ten subjects performed four types of upper arm motion in which position of shoulder joint changes (1) shoulder up and down, (2) shoulder forward and backward, (3) abduction of the upper limbs 90 deg. and (4) abduction of the upper limbs 180 deg. The position of the shoulder, elbow and wrist obtained from the inertial sensor was compared with reference obtained by optical motion capture system. The result demonstrated that proposed method could be used to measure the motion between sternoclavicular joint and acromioclavicular joint. Also, the error significantly decreased in both side shoulder joint during all motion. Therefore, the proposed method can observe the clavicle motion and provides high precision motion analysis of upper limbs.
Mainly produced on roll-to-roll systems, plastic films are used in various high functional products. During the final stage of the production, the films are continuously wound into a roll, which is then shipped to storage and transported; in some cases it is heat-treated at various temperatures. Over time, the in-roll stress of the roll will change as a result of thermal strain and the viscoelastic properties. These factors can generate roll defects such as slippage or wrinkling. Based on the optimum design technique, this paper describes an optimization method for wind-up tension that prevents roll defects caused by thermo-viscoelastic properties. Experimentation confirms the optimized tension and shows that the in-roll stress distributions are significantly improved, thus preventing both wrinkles and slippage.
In this paper, palpation motions for prostate gland were measured using a prostate examination simulator and motion capture system in order to clarify effective motions for accurate diagnosis. It is difficult for students to learn how to make a palpation motion and what information to obtain during palpation. Quantitative evaluation of palpation motion is demanded. Firstly, the prostate examination simulator was developed and six kinds of prostate models, including a healthy model, a cancer model, and a hypertrophy model, were prepared as palpation samples. Next, by using these measurement system, prostate palpation motions by a expert and five students were measured. While participants diagnose the presence of lumps in prostate models and the size of prostate, fingertip position and force applying on prostate models were measured. From the results, it was confirmed that the expert diagnosed the state of prostate glands more accurately. Then motion analyses for trajectory of fingertip, contact force, and finger posture were carried out and motion characteristics between the expert and students were compared. From these results about both of trajectory and contact force, and it was found that the expert commonly explored over the whole of models by relative larger contact force than students do, it was suggested that the expert simultaneously explores presence of lumps and the shape of prostate. And from the results of analysis on finger posture, it was found that palpating the entire prostate with the fingertip is effective. As a results, the motion characteristics of the expert were extracted by using the developed system.
A magnetically levitated double-layered cylinder has been developed for windage loss reduction of the high speed spindle that is rotating inside the inner cylinder. An axial position of each cylinder is actively controlled whereas radial and tilting motions are passively stabilized by the magnetic coupling between the cylinder and the stator. Based on the finite-element-method (FEM) analysis results, a prototype machine was built and tested. When the spindle was driven at 12000 rpm, the magnetically suspended inner cylinder was rotated at 4500 rpm. It is demonstrated that the magnetically levitated cylinder is effective for windage loss reduction when the spindle speed was more than 8000 rpm.
A high-efficiency planarization technique for preprocessing before final polishing is needed for hard-to-machine wide-band-gap semiconductors, such as silicon carbide (SiC), gallium nitride, and diamond. We proposed a novel planarization method that combines chemical mechanical polishing (CMP) and atmospheric-pressure plasma etching (plasma chemical vaporization machining [P-CVM]) and developed a prototype of the basic type CMP/P-CVM combined processing system. This prototype has a mechanical polishing part for introducing a damaged layer on the convex part of the sample surface and a P-CVM part for efficient etching of the damaged layer. Process conditions for plasma generation were determined in order to minimize the optical emission intensity ratio of nitrogen to helium because nitrogen comes from circumstance air and should not exist in the plasma region. Process conditions for mechanical polishing were determined in order to efficiently generate a damaged layer only on the convex part of the sample surface. The combined process was performed using a SiC substrate on which the mesa structure was fabricated as a sample. As a result, we found that the convex parts of the mesa structure were preferentially removed and the surface of the sample was planarized. We also found that the decreasing rate of the peak-to-valley value of the mesa structure obtained by CMP/P-CVM combined processing was approximately seven times greater than that during mechanical polishing.
To face the decrease of lifestyle comfort, the augmentation of hypothermia risks, and the deterioration of labor productivity resulting from energy consumption reduction policies, we have been proposing a wearable air-conditioning device worn like a scarf. This paper reports evaluation results of this wearable air-conditioning device’s effectiveness regarding comfort in hot summer office environment. We studied through trial subjects how neck cooling affects (1) subjective evaluation on comfort, thermic, and sweat sensations, and (2) human physiology when performing various deskwork tasks in summer heat environment. The environment of a typical Japanese office space in summer heat were reproduced using an environment control room. The environment control room’s temperature, humidity and wind velocity were set to re-create summer heat office environment (32°C, 60%, 0.15 m/s). 16 healthy subjects sat in the room in both normal condition and neck cooling condition. All subjects were dressed respecting the standard “cool-biz” dress code in Japan. (1) Comfort sensation, thermic sensation, and sweat sensation were evaluated by self-assessment. For all subjects, both discomfort sensation, heat sensation, and humidity sensation increased together with room temperature elevation, such we can understand that there is a clear correlation between environment temperature and comfort regarding temperature sensation. (2) Furthermore, we could quantitatively define the correlation between self-assessment, temperature variations, and physiological signals such as sweat amount and heart rate variability, by investigating the individual differences for comfort/discomfort in both normal and neck cooling conditions. Experimental results of this study show that using the wearable air-conditioning device in summer heat office, air-conditioner can be turned off or temperature set higher, without affecting comfort.
This study investigated the contact interface behavior between a wafer and a polishing pad in sapphire- chemical mechanical polishing (CMP) for considering the improvement of the removal rate. In our previous study we clarified that the linear velocity ratio, defined as the ratio of slurry flow velocity to pad linear velocity, remarkably affected the stability of the removal rate. The effect of the linear velocity ratio was discussed from the viewpoints of the slurry type. It was found that the slurry type changed the slurry film thickness between the wafer and the polishing pad. The relationship between the slurry film thickness and the surface asperity of the polishing pad was found to affect the linear velocity and the removal rate. As a result, we concluded the linear velocity ratio was an effective parameter for considering the CMP mechanism.
This paper analyses two control strategies, linear and nonlinear, for a 5-axis magnetic suspension system built with two three pole combined radial and axial bearings. Therein soft magnetic composites (SMC) are used as iron core material to carry the required three-dimensional flux distribution. While the linear approach has been designed around the CLARKE-Transformation to stabilize the bearing, the nonlinear one is based on feedback linearization to achieve a stable system even in the case of minimal bias flux. The paper outlines the control strategies and the controller design. Both schemes are compared regarding command response, decoupling performance and stability margin based on experimental results in the time and the frequency domain.
The paper describes the structure of a novel 6 DOF planar magnetic drive system with nanometer accuracy. Some details of the model based design are described and some performance and qualification results are given. A main advantage of the system is that it uses only six, i.e. the minimum number of sensors and coils to control all six degrees of freedom what keeps the system simple and makes it very effective. Furthermore the measurement system and the actuators are completely located below the slider; hence the platform is freely accessible from above and does not need any wiring connection since only passive parts as permanent magnets and grid plates are placed in the moved part of the platform.
Backup Bearings (BuB) must be designed to withstand the shock loads which occur during impacts with heavy and/or high-speed rotors. Both experimental testing and transient dynamic simulation are necessary for the study of BuB performance. This paper presents the transient dynamic simulation methodology developed within SIEMENS for the study of full-scale rotor landings in rolling element BuBs. The developed models were validated with a substantial landing program led and performed by SIEMENS, whose objective was to qualify the safe operation of hybrid rolling element BuBs for an industrial application utilizing an AMB-levitated 9 ton supercritical motor. The paper describes the BuB model, summarizes the simulation results and offers a comparison to experimental measurements from the aforementioned successful landing tests program.
This paper deals with interface shape optimum design of multi-material structures for the delamination strength problem. The optimum design problem is formulated as a non-parametric shape optimization problem in which the interface variation in the normal direction is considered as a design variable. The maximum value of a delamination function, an index of the delamination strength, is defined as an objective function subject to a volume constraint. The shape sensitivity, called shape gradient function, is derived by using the material derivative method and the adjoint variable method, and is applied to the H1 gradient method to determine the optimal interface shape. With this method, the maximum value of the delamination function can be minimized while the smooth optimal interface shape can be obtained without any shape design parametrization. Several interface shape design examples are presented to verify the validity and practical utility of the proposed method.
Poly(vinylidene fluoride) (PVDF) has four crystalline structures (α, β, γ and δ phase structures) in solid state. Only α-phase structure shows no crystal dipole, but this phase structure is converted easily into other phase structures according to some schemes. Generally, PVDF is given uniaxial stretch and polarization processes in order to convert into β-phase structure before sensor and actuator film use. However, we recently found a novel method in which PVDF film structure became β-phase without mechanical deformation processes. Furthermore, this technique enables us to apply printing technology, and realize the creation of free-form 3D sensor and actuators. No one can see free-form PVDF printer up to the present. The aim of the present study is to evaluate the crystalline structure and cross-sectional profile for PVDF films fabricated by present method. In addition, a novel PVDF printer, which can draw free-form 2D PVDF film, is developed on the basis of experimental results. First, a PVDF film is fabricated by dropping and drying a PVDF solution droplet. In this film fabrication, some PVDF solution droplets are prepared by changing the combination of the PVDF solution drop quantity and PVDF concentration in solution. Second, their PVDF crystalline structure is analyzed with an X-ray diffraction device. Then, PVDF film cross-sectional profile is measured with 3D shape measurement machine. In addition, the PVDF crystallinity degree is measured by differential scanning calorimetry. Third, a novel PVDF printer system is developed on the basis of present fabrication method. Then, the outline of free-draw 2D picture is printed as PVDF point drawing film on a 12mm×12mm glass plate, and the accuracy is investigated for printed PVDF films.
The use of carbon fiber reinforced plastic (CFRP) has contributed in producing light-weighted and strong aircraft structures. However, the low impact resistance of CFRP makes it easier for internal damages to occur. By using thin-ply prepeg with thickness of less than 0.05 mm, laminates with smaller differences in fiber orientation angle and with the same thickness as the conventional laminates can be formed. This study investigates and compares the mechanical properties and damage behaviours between quasi-isotropic laminates with fiber orientation angle mismatch of 45 degrees (45QI) and laminates with small fiber orientation angle mismatch of 15 degrees (15QI). Both laminates are loaded in tension in 0, 7.5, 15 and 22.5 degrees. Low velocity impact tests are also conducted. From tensile testing, 15QI laminates shows more isotropic properties in strength than 45QI. Damages were observed by using microscopic and X-ray images. Crack propagation in width direction can be prevented in 15QI laminates. From low velocity impact testing, we understand that impact responses are not depending so much on the fiber orientation angle mismatch. In terms of internal damage, 15QI laminates has smaller delaminated area near the impact point compared to 45QI laminates.
The friction of filled rubber on a rough surface is mainly determined by the rubber viscoelasticity and the surface property of multiple-scale asperities that can be represented by the power spectral density of the surface profile (i.e., power spectrum of surface roughness). This paper investigates a prediction model of rubber friction on dry and wet surfaces with large roughness under lightly squeezing, and finds a high stationary friction coefficient that depends on sliding speed. To this end, we demonstrated friction testing at low velocities with carbon-black-filled rubber and a hard substrate having self-affine surface roughness. From the experiment results, we estimated the hysteresis friction coefficient related to energy dissipation resulting from cyclic deformations of the viscoelastic rubber by applying the theory developed by Persson [(J. Chem. Phys. 115, 3840 (2001)]. We discussed the additional factor, an adhesion force, which also increases the friction coefficient. We concluded that the hysteresis loss of rubber viscoelastic deformation contributes most of the friction force, accounting for the nonlinear viscoelastic behavior of filled rubber, and that the operative surface wavelength extends to the order of micrometers.
Sintered materials are commonly used in industrial equipment, including bearing components. These materials include bimetals consisting of steel backed sintered bronze lined bushings. In particular, 90Cu-10Sn (mass%) bronze is widely used in bearing components. Lead bronze, in which the lead serves as a solid lubricant, is being replaced with other materials, among which are sulfide-dispersed bronzes. In sulfide-dispersed bronze, sulfides instead of lead play the role of solid lubricant. However, the sulfides in the bronze may be subject to chemical reduction during sintering, especially when this is carried out under a reducing atmosphere containing hydrogen gas. In this study, we investigate the effect of the sulfides on the bronze, with a focus on the hardness of the bronze matrix and the reaction between sulfides and hydrogen gas. Water-atomized powders were prepared for comparison of the sintering behavior. The sintering temperature in the tests was 1123 K. From the phase diagram of the Cu-Sn system, the liquid phase starts to form into bronze containing 20 mass% Sn at approximately 1123 K; thus, some conditions undergo liquid-phase sintering. Sulfides are observed to disappear from sintered bronze surfaces under a reducing atmosphere. However, the sulfides that are not in a solid solution do not affect the hardness of the bronze matrix, which does, however, depend on the tin content.
A series of study is presented to develop a prediction method for pipe wall thinning in power plants in order to improve the maintenance management for piping system. As the first report, experiments for flow-accelerated corrosion (FAC) of carbon steel specimens were conducted and basic data were obtained, focusing on relatively low temperature condition. FAC rate is seen to decrease by lowering temperature and the trend curve tends to remains to keep considerable level in lower temperature around 50 °C. Obtained data would mean that FAC susceptibility of pipeline in condensate demineralizer downstream and deaerator upstream in PWR plants is comparable. In terms of pH, a large drop in FAC rate is seen around pH 9.0 as in previous studies, and its ratio of pH 9.2 to pH 7.0 is approximately 1/10. This ratio fairly agrees with iron solubility in each pH condition at 150 °C while it is smaller in lower temperature condition, which may require additional effect related to pH and temperature to be considered to evaluate the FAC rate. The effect of iron contents on FAC rate is confirmed by referring to saturation solubility of iron. It is suggested that FAC may occur even when the iron concentration in the bulk water is in saturation level, which should be considered in the modelling process for FAC prediction.
Various sizes of high-density biomass briquette, named ‘Bio-coke,’ were produced from spent green tea grounds. The mechanical properties at room temperature of the Bio-coke samples were investigated using a compression testing machine. From the results, the relationship between the specimen size of Bio-coke and the ultimate compressive strength at room temperature showed that the ultimate compressive strength depends on the specimen size of Bio-coke. The maximum value of the ultimate compressive strength among the different specimen sizes of Bio-coke was at 67 MPa, obtained from the 12-mm diameter sample. In addition, at 12 mm diameter or smaller, there is hardly any difference in the ultimate compressive strengths measured. Hence, the cold compressive strength properties are divided into two groups based on the uniformity of the structure of the main components along the horizontal cross section of a Bio-coke. Results indicate that the state of the structure, composed of cellulose, hemi-cellulose, and lignin, appears to be consistent resulting from uniform permeation conditions at the 12-mm diameter or smaller samples. Meanwhile, at diameters of 20 mm or larger, the condition of the periphery of the samples were not consistent with that of the middle region because of the temperature, stress gradient and number of void occurring inside the Bio-coke caused by specimen size effect.
For the effective use of motor power, an appropriate gear ratio has to be selected according to robot tasks and motions. Because a jumping robot, in particular, requires both high torque and high velocity properties through its motion, a varying gear ratio will realize a high performance. Moreover, its varying property has to be optimally designed and realized. In this paper, we design a jumping robot with a non-circular gear which changes the gear ratio through the motion for the higher jumping. The gear ratio is optimized so that the motor power is maximized, and the change of the gear ratio is obtained based on a forward dynamical analysis. The optimized gear ratio is realized by a non-circular gear considering a constraint of pressure angle of gear teeth. A Jumping robot is protoptyped, and the effectiveness of the proposed design method is verified considering model perturbations of the physical parameters of the robot.
The detection of the presence of a structural abnormality in rotating machines with parts without gap, such as rigid couplings, by using the conventional method of vibration RMS, is difficult. This work investigates the application of Singular Spectral Analysis (SSA) to change detection in rotating machines. The performance of this technique is quantitatively evaluated in the scenario of misalignment in a turbopump assembly with rigid coupling. It is shown that a statistically significant change appears when using the Change Score calculated using the SSA method. Comparison with special indicators of a structural abnormality is also performed. Since the SSA detects changes in the shape of the signal, it is much more sensitive to changes related to abnormality than conventional methods or the use of special indicators.
The total length of sewer pipelines in Japan is over 440,000 kilometers. Until now, experienced inspectors have conducted visual inspections by watching in-pipe animation images that are obtained from an autonomous vehicle equipped with a CCD camera. Their inspection methods have difficulties of quantitative evaluation with high accuracy because the viewpoints depend on the judging skills of the inspectors. In this study, we developed vehicles equipped with an inertial navigation system (INS) consisting of a gyro sensor and accelerometer in order to measure unevenness of the sewer pipe accurately and quantitatively. We also aim to achieve a simple measurement scheme at comparatively low cost. To accomplish these missions, two vehicles were designed and manufactured. The first vehicle is designed for the function of driving and pulls a second vehicle. The second vehicle’s only function is measurement; it is towed and does not move independently. We use the MEMS sensor devices installed on the second vehicle to suit our particular needs of low price and small size. However, these low-priced gyro sensors are notorious for their inaccuracy (experiencing such problems as drift error). We apply the extended Kalman filter (EKF) algorithm to reduce the estimation errors. We use quaternions as state variables of the posture for the 3D coordinate system. The experimental study shows that the suggested algorithms effectively remove the errors and can lead to systematic measurement schemes to accurately determine the unevenness of the sewer pipes.
The present paper proposes a multi-objective optimization technique for smart laminated composites to maximize two conflicting objectives. The first objective is the performance of active vibration control of smart composite with piezoelectric (PZT) actuators. The second is the fundamental frequency of smart structures related to the performance of passive vibration control. Both performances of active and passive vibration control are maximized simultaneously. The vibration suppression of smart structures strongly depends on both actuator placements and vibration mode shapes. It is possible to design vibration mode shapes for laminated fibrous composites since their anisotropy for whole thickness is tailorable by arranging fiber orientation angle in each layer. This allows the smart structure with laminated composite to archive higher performance of vibration suppression than those with isotropic materials. However, the optimized structure results in lower natural frequencies than composites with typical fiber orientation angles since an effective input of control force from actuators is realized for the structure with lower stiffness. This reveals that there is a trade-off relation for smart composite structures between the performance of active vibration suppression and natural frequencies. To disclose this relation, the present study applies the effective multi-objective optimization technique, the refined non-dominated genetic algorithm (NSGAII), and obtains Pareto optimal solutions. Calculated results are successfully validated by a comparison with those from the real-time control experiment where a laser excitation technique which is effective to small sized structures is used.
A vibration suppressor is used to change the natural frequency of an elevator rope, and to prevent resonance. The elevator rope is modeled using a string. However, the vibration of the string that has a vibration suppressor has been studied for a few conditions because of its geometric nonlinearity. In this paper, an exact solution for the free vibration of a string when the position of the vibration suppressor is opposite to the pulled position is presented. In this analysis, a problem of free vibration with a vibration suppressor is transposed to a problem of forced vibration. Further, to verify the validity of this exact solution, a finite difference analysis of the string vibration with a vibration suppressor is performed. The calculated results obtained from the finite difference analysis are in good agreement with those of the exact solution.
Operational transfer path analysis (OTPA) calculates contributions of reference points to response point vibration by using only operational data. Through OTPA, effective interior noise and vibration reduction are achieved by applying intensive countermeasure to the high contributing part. However, it becomes difficult occasionally when many reference points have similar contributions by a vibration mode. In this case, obtaining high contributing vibration mode and considering how to reduce the mode become important information. In this study, we attempted to calculate the vibration mode contribution by modifying OTPA. Principal component calculated in OTPA procedure is composed of correlated vibration factors among reference points. We then considered the relationship between the principal component and the vibration mode, and associated the principal components with the vibration modes of a test structure. As a result, high contributing vibration modes to the response point could be found. In addition, information about which side of the structure (response or reference side) had better to be measured intensively was also obtained by evaluating the influence of each principal component to the response point (principal component transfer function). Finally, Several countermeasures were applied to the structure considering the principal component and vibration mode contributions. The result shows effective vibration reduction at the response point could be carried out. Through these procedures, the modified OTPA became more useful tool for applying effective countermeasure.
In this paper, the M[(1-1)-L’] FXLMS algorithm is shown to be useful in enlarging the window size for Active Acoustic Shielding (AAS) window. AAS is a system that can attenuate sound passing through an open window. In our previous study, an AAS window was fabricated with 4 AAS cells, each of which consisted of an collocated microphone and speaker. This AAS window was proved to be effective for not only single stable noise sources but also multiple and moving noise sources. The AAS system consists of many AAS cells set in an array. However, the size of the existing type AAS window is only 250mm square. Therefore in this paper, we propose the M[(1-1)-L’] FXLMS algorithm (M: number of AAS systems, L’ : number of error signals used for controlling 1 AAS cell) for controlling a larger window and a larger number of AAS cells. This algorithm is a similar to FXLMS algorithm, as each AAS cell is individually controlled by its own reference and neighboring error sensors. Six AAS cells are fixed on a rectangular window (125 × 750mm square) and controlled using 6 [(1-1)-3’ ] FXLMS. This system proved useful in controlling large number of AAS cells. In this study a simulator of the M[(1-1)-L’] FXLMS algorithm is constructed. The simulation results from the 6 [(1-1)-3’] FXLMS algorithms coincided well with the experimental results of 6 [(1-1)-3’ ] FXLMS, which suggests that a large AAS window is feasible.
Controlling of cell location is needed for some cellular applications like drug screening. Micro/nano-structured surface are used for controlling of cell location without using any chemical agents. An average roughness is of interest for investigating an effect on location of cell adhesion. However, some studies have indicated different results about cell adhesion even though using same kinds of cell line, material properties of scaffolds, and geometrical properties of scaffolds. Those studies have investigated an effect of average roughness only. An average roughness, therefore, is not sufficient for classifying the structured surface. In addition, the structured surfaces have no geometric regularity typically. To resolve these problems, the authors employed regularly arranged surface for cell culture scaffold and investigated effects of an average roughness, skewness, and kurtosis on cell adhesion. The authors used self-assembled SiO2 particles as a mask of reactive ion etching of Si wafer for fabricating micro-structured substrate. Then, geometric transferring technique of polydimethylsiloxane is used for fabricating cell culture scaffolds. An average roughness, skewness, and kurtosis of the scaffolds can be controlled by changing RF power and etching time. The structure that has negative skewness improves cell adhesion was found. It can be seen that Rsk of surface works as an important factor for cell adhesion.
This research deals with the hard turning of cemented carbide with CBN and diamond tools, and focuses on the tool performance, mainly tool wear with respect to cutting force and cutting temperature. The internal turning tests without cutting fluid are executed with the vertical machining center. Seven types of tool materials: SC, CVD-SC, two PCDs, BL-NPD (Binderless nano-polycrystalline diamond) and CBN: are selected for cutting three grades of cemented carbides WC having the different Co binder content (12%, 20% and 25%). Attrition has been found to be the main tool wear mechanism for all tools with slight adhesion of the workpiece binder on the tool face. In cutting of softest carbide WC-m (25% Co), the polycrystalline CBN tool has the lowest tool wear than any other PCD tools. In turning of harder carbides WC-d (20% Co) and WC-t (12% Co), both polycrystalline CBN and PCD cannot be used continuously due to their low hardness, and BL-NPD, SC and CVD-SC tools are applicable. And the BL-NPD tool has the best cutting performance with less flank wear. As for WC-d, extremely stable cutting can be done with BL-NPD where the principal cutting force is kept almost constant at 40 N. Only BL-NPD tool can continue to turn the hardest WC-t. In spite of turning hard materials, the tool temperatures measured are relatively low below 450°C due to the high thermal conductivities of tool materials. However, cutting temperature is directly related to the tool wear and cutting force rather than thermal conductivity of tool in turning of WC-m and WC-t.
A novel coupling was devised by utilizing the self-locking property of a belt. The torque is transmitted through a flexible belt. The belt length between the power disk and the driven shaft varies with a rotation of shaft in an off-centered condition. It causes an angular velocity fluctuation when the torque is transmitted by a single belt. In order to decrease this fluctuation in angular velocity, the looped belt method was devised. The looped belt is formed with the aid of the cam-followers to coil around the driven shaft so as to transmit torque through two points opposed. By running a looped belt so as to cancel the change in belt length between the power disk to the driven shaft, the fluctuation of angular velocity was successfully suppressed. The theory of looped belt coupling was examined. Experiments were carried out to confirm the theory of the looped belt method. Simple fatigue tests were also carried out to evaluate durability of the coupling. These tests showed that the looped belt method was quite effective in reducing angular velocity fluctuation in transmitting torque in an off-centered condition. It also has practical durability.
Slider-crank mechanisms are frequently used to convert between linear and rotational motion. When a slider-crank mechanism creates linear piston motion, a side force occurs between the cylinder sides and the piston head. The side force can be reduced using a Scotch yoke mechanism. However a Scotch yoke mechanism requires two parallel opposed sliders, therefore it is difficult to keep a precision and structure complicated each machine elements. This side force causes various problems, so authors have proposed an orthogonal double-slider joint mechanism to reduce the side force acting on the piston. We build three types of water-pump to investigate efficiency differences among the driving mechanism types, namely, a slider-crank mechanism with a crosshead, a Scotch yoke mechanism, and the orthogonal double-slider joint mechanism. We measure the input torque needed to drive a water-pump under same conditions for stroke, cylinder cross-section, and crank rotational speed. To investigate the influence of sliding frictional resistance acting on the crosshead, we compare results between the cases of driving by the slider-crank mechanism with a crosshead and the orthogonal double-slider joint mechanism. To investigate the influence of structural differences, we compare results between the cases of driving by the Scotch yoke mechanism and the orthogonal double-slider joint mechanism. We find that among the three mechanisms the orthogonal double-slider joint mechanism can drive the water-pump with the least input torque.
Planetary gear set is widely used in hybrid vehicle as a power distribution system or in electric vehicle as a high reduction system. Although it has many advantages, its noise and vibration problem has emerged. There have been many reports dealing with two-axis driving or displacement of planet gear under its condition, but we can see no report dealing with about three-axis driving. As first novel point in the present report, three-axis driving is tested on the original test stand. As second novel point in this report, characteristic of instantaneous center of the planet gear is investigated based on mechanism. Planet gear rotates and revolves at the same time during working in three-axis driving condition. Instantaneous center was defined according to velocity distribution of planet gear or superposition of velocity distribution of rotation and that of revolution with simple lumped model. Tangential speed is equal to zero at the instantaneous center, and planet gear rotates around it instantaneously. Instantaneous center moves according to the driving condition or input ratio between two inputs which input from ring gear and carrier. It is very important to consider generated inertia force due to rotation around instantaneous center, to design planetary gear set for three-axis driving. The meshing force between planet gear and ring gear and the meshing force between planet gear and sun gear have same trend and close value but they are not same value, and absolute values of ring-planet meshing force are larger than those of sun-planet meshing force. It is also confirmed that the torques around planet gear are balanced in steady condition, considering both transmission and rotation.
A novel technology for the simultaneous removal of NOx (= NO + NO2) and SOx (= SO2 + SO3) in the flue gas of a glass manufacturing system is described using a plasma-chemical hybrid process (PCHP). The exhaust gas is produced by combustion of liquefied natural gas and contains both NOx (189 - 335 ppm) and SOx (109 - 183 ppm). Lowering the flue gas temperature from more than 200 °C to less than 150 °C is required for effective NO oxidation (80% efficiency) to NO2 by ozone gas injection. Therefore, a mixture of ozone and water are sprayed by compressed air from the three-fluid spray nozzle into the exhaust duct. The ozone gas is prepared using an electrical discharge-induced nonthermal plasma apparatus. In addition, almost all of the SO2 is absorbed by a NaOH absorbent resulting in the generation of Na2SO3. Furthermore, reduction of the water-soluble NO2 by Na2SO3 to N2 affords Na2SO4, which can be reused as glass material. The highest removal efficiency of 39% for NOx is obtained when the NOx concentration is reduced from 315 ppm to 193 ppm (O3/NO = 0.32). This simultaneous de-SOx and de-NOx technology by PCHP is highly effective and promising for exhaust gas treatment for a glass manufacturing system.
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