著者

橋本 翔 小俣 弘樹 松永 久生

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.852, pp.16-00585-16-00585, 2017 (Released:2017-08-25)

参考文献数

17

被引用文献数

1

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Rolling contact fatigue (RCF) tests were conducted using rolling bearings with a micro-drilled hole on the raceway. In all the tests, fatigue crack initiated at the edge near the bottom of the hole, and then propagated by shear mode. Even in the unbroken specimens tested up to N = 1×108 cycles, a short fatigue crack was found at the edge. By using stress intensity factor (SIF) range calculated for initial defect size, fatigue life data were uniformly gathered inside a small band irrespective of the diameter and depth of the hole. In addition, it was found that the crack size dependency of threshold SIF range, which is well-known for mode I fatigue crack, also exists in mode II fatigue crack emanating under the rolling contact. The values of threshold SIF ranges obtained by the RCF tests were in good agreement with those obtained in the torsional fatigue tests under a static compression.

著者

伊東 弘行

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.852, pp.17-00080-17-00080, 2017 (Released:2017-08-25)

参考文献数

30

被引用文献数

5

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To investigate the influence of briquette size and density on the combustion behavior in both flaming and char combustion stage, the combustion experiments with the highly densified columnar briquette made from cypress sawdust were carried out. Three sizes of the briquette, φ30 mm×60 mm, φ35 mm×70 mm and φ40 mm×80 mm, of which diameter/length ratio is kept constant at 1/2 and three types of the briquette density, 900, 1100 and 1300 kg/m3 were employed. The water content of the briquette was kept around 10 wt%. The mass loss rate and the duration in both combustion stages were measured. In the flaming combustion stage, it is observed that the average mass loss rate per unit specific surface area is proportional to the briquette surface area, while it doesn't depend on the briquette density. It is expected by considering Fourier number that the flaming combustion duration is proportional to the product of the inverse square of the specific surface area and the briquette density and it is shown that the experimental results correspond to the expectation. It is found that the relationship between normalized mass loss rate and normalized time is nearly the same regardless of the briquette size and density. In the char combustion stage, normalized mass loss can be approximately expressed with the shrinking core model by assuming the effective oxygen diffusion coefficient in the ash layer for each briquette density used in this study. And it is found that the effective oxygen diffusion coefficient in the ash layer obtained by the shrinking core model decreases with increasing the briquette density.

著者

吉田 準史 川越 伸幸 河村 智博

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集C編 (ISSN:18848354)

巻号頁・発行日

vol.78, no.792, pp.2837-2847, 2012 (Released:2012-08-25)

参考文献数

12

被引用文献数

2

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Bicycle is a popular vehicle for general public because of the low price and the easy maintenance, and will be more importance vehicle by the low environmental loading in the future. Improvement of bicycle ride comfort is one of important factors to increase the popularity. In this study, subjective evaluation test and reduction of bicycle vibration were performed to improve it. In the subjective evaluation, low frequency seat vibration was found to affect the ride comfort very much. Subsequently, transfer path analysis (TPA) and hammering test were performed to obtain vibration characteristic of the bicycle for reduction of the seat vibration. Through TPA, rear frame of the bicycle was found to have high influence to seat vibration than that of front side and the vibration behavior was obtained by modal analysis. For reduction of the seat vibration, a spring was inserted to the front of the seat and steel plates were attached to rear frame to increase the stiffness. As a result, the acceleration level at running condition was decreased about 10 dB by the modification, and the ride comfort was improved so much.

著者

大久保 光 野田 悠貴 田所 千治 平田 祐樹 佐々木 信也

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.16-00543-16-00543, 2017 (Released:2017-06-25)

参考文献数

14

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Lightweight Al-Si alloy is expected as a substitute material for the cast iron of engine parts to improve fuel consumption of automobiles. In this study, the tribological properties of Al-Si alloys against diamond-like carbon (DLC) films were examined to comprehend the influences of Si particles on Al-Si alloy surfaces under lubricated with a fully formulated oil. Sliding tests were performed with a hydrogenated amorphous carbon (a-C:H) film coated steel cylinder against the five kind of Al-Si alloy disks with different Si contents. Sliding tests and surface analysis results showed that the friction coefficient of a-C:H/Al-Si tribo-pairs depended on the exposure height of Si particles on the Al-Si alloy surfaces rather than the area ratio of Si particles. The exposure height of Si particles plays important roles in determining the frictional properties of a-C:H/Al-Si tribo-pairs under lubrication with the fully formulated oil.

著者

前田 慎市 倉持 悠希 小野 涼 小原 哲郎

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.850, pp.17-00049-17-00049, 2017 (Released:2017-06-25)

参考文献数

21

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This study addressed a deflagration-to-detonation transition (DDT) process after interaction of the convex flame with a planar shock wave. High-speedvideo cameras and schlieren optical technique were utilized to observe the DDT as well as shock-flame interaction processes. A double-diaphragmshock tube was used to produce the shock wave, while the flame was produced by igniting a premixed gas of stoichiometric methane-oxygenat the observation section. Experiments were conducted by changing Mach number of the incident shock wave, Ms and a distance of flame front from the end wall, x0. As a result of schlieren photographs, flame propagation behaviors at initial stage were classified into four patterns, named as (a) coupling, (b) concave, (c) partial coupling and (d) convex type. The propagation patterns of flame were highly dependent on the initial position of flame front, x0. Under the experimental conditions, DDT was not observed when the flame had been propagated revealing (a) coupling (observed with the conditions of x0 > 110 mm) and (d) convex type (x0 < 50 mm). However, the DDT was observed following that the flame had been propagated revealing (b) concave or (c) partial coupling (50 < x0 < 110 mm). Furthermore, it was elucidated that DDT was typically caused through the following processes. (i) When the convex flame interacted with planar shock, the unburned gas was penetrated into burned gas inducing Richtmyer-Meshkov instability. (ii) The flame was highly accelerated at boundary layers behind the reflected shock. (iii) After accelerated flame propagated through the unburned shocked region, local explosion was occurred on the wall followed by detonation onset.

著者

三木 光範 大貫 正秀 杉山 吉彦 山口 哲男

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 A編 (ISSN:03875008)

巻号頁・発行日

vol.59, no.564, pp.1985-1992, 1993-08-25 (Released:2008-02-21)

参考文献数

12

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Composite pipes with structurally unsymmetric laminated configurations (SULC pipe) shows coupled deformations upon bending and torsion. Our previous study treated the static behavior of the SULC pipes, and this paper deals with their dynamic coupling behavior. The coupled bending and torsional vibration of a cantilevered SULC pipe with an eccentric weight at its free end is analyzed, neglecting the mass of the pipe and assuming that it is an undamped free vibration system with two degree of freedom, transversal and rotational displacements. It is found that the SULC pipe has an elastic principal axis apart from its geometric principal axis, and the vibration becomes uncoupled when the center of gravity of the eccentric weight is located on the elastic axis of the pipe. The effects of the fiber orientation angles and the eccentricity of the tip weight on the vibration behavior are also analyzed considering the dynamic center of rotation. The analytical results show good agreement with the experimental results.

著者

大嶋 元啓 松村 恵理子 千田 二郎 石田 耕三

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.849, pp.16-00491-16-00491, 2017 (Released:2017-05-25)

参考文献数

12

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In this study, the novel flame synthesis method using flash boiling spray is proposed in order to form the homogeneous characteristics nanoparticle. In this method, the precursors are injected and the injected precursors are evaporated by flash boiling. The evaporated precursors form vapor and the nanoparticles are formed at high temperature with flame. The factors for homogeneous characteristics of nanoparticles are precursor, flash boiling spray, flame characteristics and nozzle. These factors affect each other and affect to the nanoparticle characteristics as diameter distribution and crystal characteristics. It is necessary to optimize these factors to form homogeneous characteristics particles. In the previous study, TiO2 nanoparticles were formed and the relationship between the flame and injection characteristics, and the particle characteristics were investigated. From the result, the equivalence ratio affects to the nanoparticle crystal characteristics and injection condition affect to the particle diameter and mass fraction of anatase phase. In this paper, TiO2 nanoparticles were produced and the particle property influenced by ambient pressure and particle trapping position is investigated. As the result, the mass fraction of TiO2 anatase phase decreases by increasing ambient pressure. The rutile phase is formed at the short nanoparticle trapping position. The factors such as precursors, injection condition and fuel/oxygen flow ratio for producing the anatase phase particle in this method was discussed.

著者

加藤 学 高橋 勉

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.849, pp.17-00007-17-00007, 2017 (Released:2017-05-25)

参考文献数

12

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The technique to measure planar elongation viscosity from both mechanical and optical measurements by using two-dimensional opposing jets nozzle flow has been developed. This technique generates planar elongational flow between both nozzles and simultaneously measures reaction force acting on the nozzle and flow birefringence at the stagnation point. The correctness of elongational viscosity measured by this technique was verified from experimental results for Newtonian fluid and Maxwell fluid. Starch syrup aqueous solution and CTAB/NaSal surfactant solution are used for the Newtonian fluid and the Maxwell fluid respectively. As the results, transient behavior of nozzle reaction force and flow birefringence for Maxwell fluid show good agreement. It indicates that this technique can evaluate planar elongation viscosity for not only fluids that obey stress-optical rule but also fluids have flow birefringence property. In addition, Trouton ratio of optical results become 4 and it indicates the results from optical technique are accurate. On the other hand, the data from mechanical technique provide Trouton ratio with range 15 to 20. Trouton ratio of Newtonian fluid also shows 10 ~ 20 and these results conclude that mechanical data should be limited for qualitative evaluation. However, Trouton ratio of mechanical technique is independent from sample viscosity and elongaitonal rate. Therefore, it can provide quantitatively valuable result by using correction factor.

著者

山中 仁寛 中易 秀敏 三好 哲也 前田 多章

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.72, no.719, pp.2248-2256, 2006-07-25 (Released:2011-03-04)

参考文献数

17

被引用文献数

3

---

A new method is proposed to measure the useful field of view (UFOV) when one can recognize the objects by visual task. Since the distance from fixation point to target mark is the strength of stimuli, the psychometric curve is utilized for UFOV by the statistical estimation by Probit and Staircase methods. An approximation by ellipse is also applied to represent the contour of the UFOV. The proposed method enables one to estimate the threshold of recognition with probability that means the UFOV with the detection probability. Therefore, it is proposed in this paper to determine the threshold in any direction from fixation point of the UFOV with visual task by psychometric curve. The availabilities of the proposed method are examined for accuracy and efficiency by the experiments.

著者

奥 知久 笠木 伸英 鈴木 雄二

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.69, no.686, pp.2313-2320, 2003-10-25 (Released:2008-03-28)

参考文献数

9

被引用文献数

3

---

Micro bare-tube heat exchangers can accomplish high performance and compactness with their simple structure. In general, decreasing characteristic length leads to higher heat transfer area density at the expense of larger pressure drop. The trade-off has been so far optimized by trial and error. In the present study, simulated annealing (SA) is employed to optimize various design parameters of heat exchangers, which composes a multiple-variable highly nonlinear system. Although the heat transfer coefficient and the pressure drop on the air-side make major contribution to the total heat resistence and pumping power, empirical correlations of flow around tube bank can not predict them accurately in the low Reynolds number range, which is characteristic of compact heat exchangers. Hence, we make a series of numerical simulation for heat transfer and pressure drop of flow in the tube bank at various tube spacings and Reynolds numbers, and correlation functions are developed using an artificial neural network. Finally, optimum design is made for three types of micro bare-tube heat exchangers, i. e., heater core and radiator for automobiles, electronic equipement cooling system, and recuperator for micro gas turbine.

著者

清家 政一郎 佐々本 覚 細野 喜久雄

出版者

一般社団法人 日本機械学会

雑誌

日本機械学會論文集 (ISSN:00290270)

巻号頁・発行日

vol.40, no.329, pp.140-145, 1974-01-25 (Released:2008-03-28)

参考文献数

11

被引用文献数

1

著者

中山 江利 グエン タイ タット ホアン 戸倉 直 萩原 一郎

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.81, no.829, pp.15-00268-15-00268, 2015 (Released:2015-09-25)

参考文献数

9

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A tsunami is caused by a large coastal earthquake. We devise the foldable tsunami pod on which evacuees can get, when tsunami is approaching. The 3D model for the foldable ellipsoid body is generated by FEM software “LS-PREPOST”. We perform a numerical simulation, and confirm the safety by von Mises equivalent stress and Head Injury Criterion (HIC). As the result of the 1st simulation, it is proved that the initial model is weak to the impact force from rigid wall and obstacles and can be strained in the central part. On the other hand, an occupant hits against the inner side of the wall and can be injured. So, a seat and upper and lower bars are added to the initial model. Von Mises equivalent stress for the modified model is decreased, however is still over the ultimate strength of the 1st simulation. While, HIC value is decreased largely which is much less than the HIC safety level. This is because an occupant isn’t hit by the internal wall for an occupant restraint system. Moreover, we optimize the form and property for a tsunami pod on condition of its mass is minimized by uncoupled analysis. Finally, we confirm the validity of the optimal model by an original condition of coupled analysis.

著者

大久保 光 坪井 涼 田所 千治 佐々木 信也

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.81, no.824, pp.14-00656-14-00656, 2015 (Released:2015-04-25)

参考文献数

12

被引用文献数

1 5

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This research studied the effects of Zinc Dialkyldithiophosphate (ZnDTP) additives on the tribological properties of a H-free Diamond-like Carbon (DLC) film under boundary lubrication with oils that contained organic friction modifiers (FMs). The tribological properties were evaluated using the reciprocating type cylinder-on-disk tribo-tester. ZnDTP and three types of organic additives (GMO, glycerol mono-oleoyl ether (GME), and tallow diethanol amine (TDEA)) were added to poly-alpha olefin (PAO). Friction tests were carried out for the DLC/Steel tribo-pair under lubrication with PAO and PAO-based oils containing GMO, GME, TDEA, ZnDTP, GMO + ZnDTP, GME + ZnDTP, and TDEA + ZnDTP additives. Raman spectroscopy, Scanning Electron Microscopy (SEM), energy-dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS) were used for analyses of worn surface on the H-free DLC film. The H-free DLC film lubricated with PAO + FMs reached an ultralow friction coefficient of 0.02 - 0.03. On the other hand, The H-free DLC film lubricated with PAO + FMs + ZnDTP had increased friction coefficients compared to the PAO + FMs oils. For the lubrication added ZnDTP additive, the surface analyses demonstrated that the chemical composition of the ZnDTP-derived tribofilm depended on the combination of ZnDTP and each FM. It was concluded that the chemical composition of the ZnDTP-derived tribofilm played an important role in the friction behavior of the H-free DLC films that were lubricated with PAO + ZnDTP and PAO + FMs + ZnDTP.

著者

藤松 孝裕 廣田 真史 藤田 秀臣 岡田 修 鈴置 純

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.68, no.673, pp.2534-2541, 2002-09-25 (Released:2008-03-28)

参考文献数

19

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The deformation of the interface between a water drop and silicone-oil surface impacted by it was examined in detail. Special attention was directed to the influences of the water-drop diameter dL on the deformation of oil surface and on that of the water drop itself after the impact with the oil surface. The drop diameter was varied from 1.9 mm to 4.1 mm. The influences of dL on the shape of oil cavity at its maximum depth and on the drop shape at its maximum spread were observed conspicuously in case of minimum oil viscosity of vT=5 mm2/s. It was also found that both the maximum cavity depth ratio DM/dL and the maximum diametral deformation ratio dM/dL became smaller as dL was increased. These deformation parameters DM/dL and dM/dL could be well correlated with the impact velocity of drop uL for each oil viscosity. Moreover, in Case B, C and D, DM/dL could be correlated by a dimensionless group ReTLWeTL, and dM/dL was correlated by Re2LOh for highly viscous silicone oil of vT ≥ 5 × 103 mm2/s.

著者

大久保 光 福田 宙央 坪井 涼 田所 千治 佐々木 信也

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.82, no.838, pp.15-00679-15-00679, 2016 (Released:2016-06-25)

参考文献数

13

被引用文献数

1

---

Tribological properties of a diamond-like carbon film were investigated under lubrication with commercial fully formulated oils. Friction tests were carried out for a hydrogenated amorphous carbon (a-C:H)/steel tribopair under lubrication with the four types of fully formulated oil using a reciprocating type ball-on-disk tribo-tester. To clarify the friction and wear mechanisms, surface analysis, such as Raman spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS) and atomic force microscopy (AFM), were conducted on the wear tracks of a-C:H disks. The results of friction tests and surface analysis show that the properties of tribofilms on DLC films play important roles in determining the tribological properties of DLC films under lubrication with fully formulated oils.

著者

星川 秀利 藤本 浩志

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.69, no.680, pp.1080-1085, 2003-04-25 (Released:2008-02-26)

参考文献数

12

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The purpose of this study is to investigate the influence of lower saddle height on the knee joint. Five healthy male pedal at 60 rpm against the work load of 100 and 200 W. Three saddle heights of 80, 90 and 100% of trochanteric leg height are selected in this study. During each trial, the position data of the right lower limb's joints by the video camera and the force data of the right pedal by the force sensor are measured. Using these data, the inverse dynamics analysis is done, and the following results are obtained. The peak link force acting on the knee joint and the peak knee extension moment do not indicate any change over the three saddle heights, however, the angles at their peak values shift to the knee flexion as the lower saddle height. These results indicate that the lower saddle would overload at the knee joint.

著者

土谷 圭央 日下 聖 田中 孝之 松尾 祥和 小田 まこと 笹木 工 神島 保 山中 正紀

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.82, no.843, pp.16-00072-16-00072, 2016 (Released:2016-11-25)

参考文献数

22

被引用文献数

6

---

Anteflexion of the spine is essential for many physical activities of daily living. However, this motion places the lumbar disks because it generats heavy load due to changes in the shape of the lumbar spine and can lead to low back pain. In older to reduce low back pain, here we proposed a wearable sensor system configuration that can estimate lumbosacral alignment and lumbar load by measuring the shape of the lumbar skin when the lumbosacral alignment changes. The shape of the lumbar skin and posture angle are measured by using curvature sensors and accelerometers. In addition, the system must be constructed in consideration of the physique, in order to absorb in a variety of human. We proposed this system by measuring the body parameters of anteflexion and studied the change in dimensions of the lumbar spine from changes in posture. By extracting the dimensions of the lumbosacral spine in X-ray images, the attitude angle, body surface area and the dimensions of the lumbosacral spine have relevance. The lumbosacral dimensions calibration method was developed by using that relation. Lumbosacral alignment estimation considering the difference in physiques is developed, and lumbosacral spine alignment was to improve the estimation accuracy. The proposed method could improve accuracy lumbosacral alignment estimation.

著者

藤本 浩志 加藤 一郎

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.61, no.582, pp.641-646, 1995-02-25 (Released:2008-02-26)

参考文献数

8

被引用文献数

1 1

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This paper deals with the method of controlling an A/K prosthesis which allows disabled persons to ascend a staircase. Since conventional A/K prostheses are capable of only the function of walking on a level surface, disabled persons wearing conventional A/K prostheses have been compelled to walk on stairs with unnatural posture. The research study of developing powered A/K prostheses has the important themes of not only developing the mechanism of the prosthesis but also devising the controlling method. By measuring the axial forces acting on the socket ; which is the man-machine-interface, during walking, using the six axis force-moment sensor, the torque of a disabled side hip joint was calculated. We devised the control method using this torque as the control signal. Results of clinical walking experiments showed that a subject wearing the A/K prosthesis was able to walk with a joint angle pattern similar to that of unaffected persons. Furthermore, from the results of the inverse dynamics analysis, the subject was found to generate a similar torque pattern and power pattern at his disabled side hip joint. Thus the effectiveness of the controlling method proposed in this study was confirmed.

著者

Yuki KINOSHITA Tetsuo YAMADA Surendra M. GUPTA Aya ISHIGAKI Masato INOUE

出版者

一般社団法人 日本機械学会

雑誌

Journal of Advanced Mechanical Design, Systems, and Manufacturing (ISSN:18813054)

巻号頁・発行日

vol.10, no.3, pp.JAMDSM0052-JAMDSM0052, 2016 (Released:2016-07-01)

参考文献数

22

被引用文献数

8

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For green supply chains, it is essential to disassemble and recycle end-of-life (EOL) assembled products for material circulation. In order to establish disassembly plants environmentally friendly and economical manner, a disassembly parts selection is often carried out. Each part has a different recycling rate and cost, and all parts have precedence relationships among disassembly tasks. Igarashi et al. (2014) [International Journal of Industrial Engineering and Management Systems, Vol.13, No.1, pp.52-66] proposed a disassembly parts selection method that is carried out in an environmentally friendly and economical manner with non-destructive or destructive disassembly with integer programming with ε constraint. However, calculated efforts are required to achieve optimum solutions for the ε constraint method. On the other hand, goal programming is well known as an effective way to solve multi-criteria decision-making problems. This study proposes a bi-objective disassembly parts selection with recycling rate and cost using goal programming, and analyzes multiple types of EOL assembled products and disassembly parts selection. First, an environmentally friendly and economical disassembly parts selection is addressed using a 3D-CAD and Recyclability Evaluation Method (REM) developed by Hitachi Ltd. Next, the environmentally friendly and economical disassembly parts selection is formulated with goal programming. Finally, a case study is quantitatively discussed by comparing different types of assembled products and goal programming parameters. It is demonstrated that the proposal method by goal programming in this study finds the same solutions with the lower number of numerical experiments as that with the ε constraint method.

著者

髙村 藤寿 太田 順子 尾崎 光則 西澤 泉

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

pp.16-00070, (Released:2016-10-07)

参考文献数

24

被引用文献数

2

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In this paper, Technology Circulation Model is proposed as a new management method for companies with existing business domains that plan and execute industry-university collaborations to make innovations. Based on this model, we discuss concepts for effective planning and execution of industry-university collaborations through real cases. Technology Circulation means a flow of Science - Technology - Engineering - Manufacturing & Services, then to Science again. We show the effectiveness of the framework of industry-university collaborations, in which; empirically used techniques are visualized, complicated phenomena are explained simply, new sciences are established, and current industrial technologies are made more sophisticated. By starting from visualization of currently used technologies, it becomes possible to execute efficient industry-university collaborations matching the directions of business needs and academic seeds.