It is well known that the mechanical properties of human bones change with aging, accompanied with the geometrical changes. While structure model index (SMI) is often employed to quantitatively evaluate the bone shapes, it is impossible that changes in shapes of bodies with concave and convex faces are accurately distinguished. In this study, SMI was extended to solve the problem, and this extended version of SMI (ESMI) was adapted to vertebral body models, where the models were built based on young and old aged vertebrae. Uniaxial compressive deformations of the vertebral body models were also numerically simulated by finite element method, and the relationship between the shapes and stress concentration factors was organized by ESMI. The results showed that ESMI distinguish shape changes of vertebral bodies more accurately than SMI, and the ease of stress concentration depending on the diameter of narrow part in vertebral body was successfully evaluated by ESMI.
Many building projects are complex because they involve many elements based on different technical and product areas. There is a lot of information in those elements, which is complex, uncertain, and always difficult to grasp accurately. This paper discusses the aspect of Information on the process of construction projects, and tries to contribute to establish a fundamental method to understand the characteristics of design information with new technologies such as Building Information Modeling. Especially, the theoretical analysis of information creation on the process of construction projects shows the important points of issues for the foundation of technology development.
The purpose of this study is to propose a modified average flow model that can be used for mechanical seals with parallel sealing faces, and clarify their lubrication characteristics. The general average flow model established by Patir et al. could not consider the effects of surface roughness between parallel faces. In the present model, the flow factors with considering side leakage effects between parallel lubricating faces are implemented. In addition, the model allows one to consider the additional expected hydrodynamic pressure generated owing to the relative motion of rough surfaces. The flow factors are evaluated as the average for several different surfaces with the same statistical properties. In this first report, the effects of the root mean square roughness on the lubrication characteristics are investigated, assuming that the probability density function of the roughness follows the normal distribution. The results show that as the root mean square roughness increases, the flow rate increases. In addition, the optimal roughness for the friction coefficient is changed with the rotational speed.
The currently used dredging method of scallop harvesting includes problems such as the following: ingress of foreign matter in the shells, harvesting of other sea creatures, and damage to the shells. To address these issues and improve the productivity of harvesting, this study proposes a new harvesting method using a robot arm. A dedicated gripper for scallop harvesting is needed for this harvesting method; however, there are no grippers specifically designed for scallops. Hence, the purpose of this study is to develop a new gripper dedicated for scallops. The harvesting gripper must meet these specifications: minimal sand ingress in the scallops, target selectability, secure gripping, power saving, and pressure resistance. To meet these demands, this study focuses on the phenomenon of negative pressure-induced adsorption with a non-electric spring actuator. We attempted to develop a negative pressure adsorption gripper with a spring structure and conducted a harvesting experiment using the developed gripper in the laboratory. The experimental results indicated that the developed gripper succeeded in gripping scallops.
In the present paper, a method to scan the front face of a measured object behind an obstacle around a scanner using a two-dimensional laser range scanner and mirrors is described. The distances and angles from the scanner to the measured object through the mirrors avoid the obstacle at a constant angle, which are measured radially by the laser. Thus, laser-reflecting points on the front face of the measured object behind the obstacle at a constant angle are obtained. The construction and function of the proposed scanning method using the scanner and mirrors are presented, based on which coordinate systems are set to design the proposed scanning method. The coordinates and angles of the obstacle and mirrors, trajectories of the laser, installation of the scanner and mirrors, and coordinates of the laser-reflecting points on the front face of the measured object are designed based on the coordinate systems. An experimental equipment is designed as described above, to evaluate the performance of the proposed scanning method. The equipment is built using an actual scanner and mirrors, and the methodologies using this equipment are set. Subsequently, the results are discussed.
In the 1st report, authors defined design goals for additive manufactured violin. A process to achieve the design goals were established. And then authors implemented parts of the process and found one of design configurations of the violin that may achieve the design goals. In this report, the violin based on the design configuration was fabricated using three additive manufacturing systems. The violin was evaluated through parts of the process. As a result, the authors obtained the additive manufactured violin that achieved the design goals.
Additive manufacturing technology is being researched and developed not only for prototyping but also for various application areas. Authors have been researching additive manufactured violin. In this report, the authors defined four design goals for the additive manufactured violin. Then, a process of design, manufacturing, and evaluation to achieve the design goals was built. 3D scanning, 3D-CAD, and CAE were used in the process. Several parts of the process were implemented, and a 3D-CAD model of a violin was created. The authors have found one of design configurations of the additive manufactured violin that may achieve the four design goals using the 3D-CAD model.
Gas cutting is one of the main methods used for cutting steel plates. Gas cutting produces molten steel and it cools down and adheres strongly to the back of the steel. This adhesion is called slag, and it is difficult to remove. In this study, a method of blowing compressed air onto a steel plate in gas cutting to blow away the molten metal, that is, the "Compressed Air Blow Support Method" was conceived. A device for blowing compressed air onto a steel plate was fabricated, and the effects of the blowing direction and input compression pressure on the amount of slag adhering to the steel were investigated. When the compressed air was blown onto the steel plate in the direction perpendicular to the direction of gas cutting, the molten metal stuck to the bottom of the steel plate was blown away and almost no slag adhesion was observed. When the input pressure was changed from 0.1, 0.2 and 0.3 MPa, the amount of slag adhered was large at the highest blowing pressure of 0.3 MPa, and the amount of slag adhered was minimal at 0.2 MPa.