Joho tsushin shijo ni okeru kokyaku no sentaku kodo no yoin ni kansuru kenkyu

制度:新 ; 報告番号:甲3513号 ; 学位の種類:博士(国際情報通信学) ; 授与年月日:2012/3/15 ; 早大学位記番号:新585

Analysis of Laser Cut Living Hinge Pattern Design

Living hinges are flexure bearings that consist of one material which makes up both the hinge and rigid end connections. They are typically made of plastics that can naturally bend without causing permanent strain. Plastic living hinges usually consist of a flat, thin strip of material connecting two ends, and have a wide range of commercial applications. The function of these living hinges can be replicated in plywood samples through subtractive manufacturing. Laser cut patterns produced in plywood samples reduce the flexural rigidity of the material and are popular amongst hobbyists

Identify and Analyze the Most Important Factors Affecting the Safety of Employees in Construction Sites in Iraq

تعد المشاريع الانشائية من أخطر الصناعات الانشائية من حيث تعرض سلامة وصحة العمال للحوادث المتنوعة والخطرة اثناء عملية البناء. إذ تبين احصائيات منظمة العمل الدولية وجود حادثة وفاة كل ثلاثة دقائق نتيجة إصابة العمال وان هنالك اربع إصابات مختلفة تحدث في العالم كل ثانية.  وقد تم تحديد صناعة البناء باعتبارها واحدة من الصناعات الأكثر خطورة، وذلك بسبب طبيعة العمل الناتج عن تكامل المواد والأدوات والبيئة والعوامل البشرية المختلفة حيث من الضروري إعطاء أهمية قصوى للسلامة المهنية والصحية للعمالة في مواقع المشاريع الانشائية وذلك لتقليل المخاطر والخسائر بين العمالة. حيث يعاني العراق من عدم الاهتمام بسلامة وصحة العمالة. ورغم أهمية السلامة والصحة للعاملين نلاحظ ان الأبحاث التي تطرقت لموضوع السلامة في المشاريع الانشائية تضل قليلة. يبدو أن الدراسات التجريبية حول تأثير الثقافة الوطنية على مواقف وسلوك وأداء السلامة قليلة. لا يبدو من غير المعقول أن نتوقع أن تختلف مواقف الناس تجاه المخاطر وفقًا للقيم والمعتقدات والافتراضات العميقة. لذا تم التركيز في هذا على اهم العوامل المؤثرة على سلامة وصحة العاملين في المواقع الانشائية وعمل اقتراحات حول من يتحمل هذه الإصابات صاحب العمل او المقاول ويتم ذكر كافة إجراءات السلامة اثناء كتابة عقد المقاولة ووضعها من الشروط الأساسية في المشروع.Construction sites are among the most dangerous construction industries in terms of exposing the safety and health of workers to various dangerous accidents during the construction process. Where the statistics of the International Labor Organization show that there is one death every three minutes as a result of a work injury and that there are four different injuries occurring in the world every second. The construction industry has been identified as one of the most dangerous industries, due to the nature of the work resulting from the integration of materials, tools, the environment and various human factors. A message of worker safety consideration during design sites. It is necessary to give the highest importance to the occupational and health safety of workers in construction projects sites in order to reduce risks and losses. Among worker. Iraq suffers from a lack of attention to safety and health of employment. Despite the importance of safety and health for workers, we note that research that deals with on the issue of safety in construction projects is still very little. Empirical studies on the effect of national culture on safety attitudes, behavior, and performance appear to be few. It does not seem unreasonable to expect people’s attitudes toward risk to differ according to the deep values, beliefs and assumptions that local culture influences safety in projects. Therefore, the focus was on the most important factors affecting the safety and health of workers in construction sites and making suggestions about who bears these injuries to the employer or contractor and all safety measures are mentioned while writing the contract and placing them as basic conditions in the project.                                                     &nbsp

Frustration Propagation in Tubular Foldable Mechanisms

Shell mechanisms are patterned surface-like structures with compliant deformation modes that allow them to change shape drastically. Examples include many origami and kirigami tessellations as well as other periodic truss mechanisms. The deployment paths of a shell mechanism are greatly constrained by the inextensibility of the constitutive material locally, and by the compatibility requirements of surface geometry globally. With notable exceptions (e.g., Miura-ori), the deployment of a shell mechanism often couples in-plane stretching and out-of-plane bending. Here, we investigate the repercussions of this kinematic coupling in the presence of geometric confinement, specifically in tubular states. We demonstrate that the confinement in the hoop direction leads to a frustration that propagates axially as if by buckling. We fully characterize this phenomenon in terms of amplitude, wavelength, and mode shape, in the asymptotic regime where the size of the unit cell of the mechanism~$r$ is small compared to the typical radius of curvature~$\rho$. In particular, we conclude that the amplitude and wavelength of the frustration are of order $\sqrt{r/\rho}$ and that the mode shape is an elastica solution. Derivations are carried out for a particular pyramidal truss mechanism. Findings are supported by numerical solutions of the exact kinematics.Comment: 7 figures, added figures and references, corrected typo

Observation of Nonreciprocal Wave Propagation in a Dynamic Phononic Lattice

Acoustic waves in a linear time-invariant medium are generally reciprocal; however, reciprocity can break down in a time-variant system. In this Letter, we report on an experimental demonstration of nonreciprocity in a dynamic one-dimensional phononic crystal, where the local elastic properties are dependent on time. The system consists of an array of repelling magnets, and the on-site elastic potentials of the constitutive elements are modulated by an array of electromagnets. The modulation in time breaks time-reversal symmetry and opens a directional band gap in the dispersion relation. As shown by experimental and numerical results, nonreciprocal mechanical systems like the one presented here offer opportunities to create phononic diodes that can serve for rectification applications