A Study on Disassemblability and Feasibility of Component Reuse of Mobile Phones

AbstractReuse is a good way to prolong product life and reduce environmental impact due to production. When the whole product cannot be reused, reuse of components might be the option. Mobile phone is a product in which technological progresses are made every year. Components of mobile phones often have high qualities. Such components may have good functionalities after the lives of the phones themselves. This paper focuses on mobile phone components and tries to find the feasibility of reuse. Because of the functionality of the component, the paper selects liquid crystal display (LCD) as the target of reuse. Firstly, disassemble experiments are carried out to clarify disassemble time and bottlenecks of dismantling. Secondly, design improvements to enhance disassemblability are discussed. Then, by comparing LCDs of mobile phones with target products, technological feasibility is examined. Finally, the paper concludes component reuse of LCD can be feasible by implementing design for disassembly

A Study on Separating Characteristics of Metals towards Remote Recycling

AbstractThis study focuses on disassembly and separation processes of recycling of used electronic products. In the previous study, the authors have proposed a concept of remote recycling. The concept can replace manual disassembly and reduce the recycling cost, by carrying out the operation from where labor is relatively inexpensive and sufficient. As a typical electronic product, the paper takes mobile phone as an example and evaluates characteristics in separating valuable metals from used products to examine the feasibility of the concept. It is said that most of the valuable metals of the used electronics are contained in Printed Circuit Board (PCB). Experiment results showed that metals such as Fe, Cu, Al, Cr, Ni and Mg were much more concentrated in roughly crushed and visually separated particles than in manually disassembled PCB. Thus, the paper concluded that visual separation of valuable metals is possible, and this result will be a first step towards implementation of remote recycling

Impact of Separator Thickness on Temperature Distribution in Single Cell of Polymer Electrolyte Fuel Cell Operated at Higher Temperature of 90 °C and 100 °C

The New Energy and Industry Technology Development Organization (NEDO) road map (Japan, 2017) has proposed that a polymer electrolyte fuel cell (PEFC) system, which operates at a temperature of 90 °C and 100 °C, be applied for stationary and mobility usage, respectively. This study suggests using a thin polymer electrolyte membrane (PEM) and a thin gas diffusion layer (GDL), at the same time, to achieve better power-generation performance, at a higher temperature than usual. The focus of this paper is to clarify the effect of separator thickness on the distribution of temperature at the reaction surface (Treact), with the relative humidity (RH) of the supply gasses and initial operation temperature (Tini), quantitatively. In this study, separator thickness is investigated in a system using a thin PEM and a thin GDL. Moreover, this study investigates the difference between the maximum temperature and the minimum temperature obtained from the distribution of Treact as well as the relation between the standard deviation of Treact − Tini and total voltage, to clarify the effect of separator thickness. The impact of the flow rates of the supply gases on the distribution of Treact is not large, among the investigated conditions. It is noticed that the temperature distribution is wider when a separator thickness of 2.0 mm is selected. On the other hand, it is observed that the temperature increases along with the gas flow through the gas channel, by approximately 2 °C, when using a separator thickness between 1.5 mm and 1.0 mm. The impact of the RH on the distributions of Treact − Tini is larger at Tini = 100 °C, when a separator thickness of 1.0 mm is selected. It is revealed that the wider temperature distribution provides a reduction in power-generation performance. This study proposes that the thin separators, i.e., with a thickness of 1.5 mm and 1.0 mm, are not suitable for higher temperature operation than usual.publishedVersio

Microfactory and a design evaluation method for miniature machine tools.

ABSTRACT A microfactory is a system that can perform manufacturing processes within a very limited space such as a desktop. However, design optimization of miniature machine tools in microfactories have not been studied enough. Since the miniature machine tool designs are not supported by existing design experience as normal machine tools are, design guidelines for miniature machine tool are strongly demanded. And a design tool to analyze machine performance without prototyping will be also necessary because the miniature machines have wider design choices than normal machine tools have, based on its small size and less constraints. This paper focuses on a robust design tool combining form-shaping theory with the Taguchi method, to roughly estimate performance of miniature machine tools at its conceptual design stages. The effort not only identifies critical design parameters that have significant influence on the machining tolerance, but also determines which structure has the best theoretical performance. The paper tells that the proposing design evaluation method can help machine tool designers in determining the optimum structure of a miniature machine tool. The study also realizes two designs of miniature mills to measure positioning errors. The measurement ensures the design evaluation method can predict the machine performance well enough for usage in conceptual design stages. The paper concludes that the design evaluation method is applicable to a systematic miniaturization of a machine tool

Proposal of an Efficiency Index for Supporting System Configuration Design

Demands of various miniature mechanical parts and products such as for watches, cameras, medical devices, miniature die-sets, and so on, are increasing more and more. Contrarily, manufacturing systems for those parts and products are becoming larger and more complicated. The research group including the authors developed the first prototype of a microfactory which consisted of miniature machine tools and manipulators, in 2000, as a countermeasure for the situation. We insisted that the advantage of the microfactory would be its capability to reduce environmental impact and costs of manufacturing, especially for diverse-types-and-small-quantity production. Since the smallness of the each machine enables factory layout change, the microfactory can control the increase of the costs when the designs of products have been modified. By replacing conventional manufacturing systems by microfactories, electrical power and initial cost of the machines can be also reduced. On the other hand, machines of the microfactory should be designed small and simple, to ensure the abovementioned advantages. It means that those machines cannot have extra power, throughput, process capability, and so on. So, in the microfactory, many design issues such as machine design, system design and process design should be solved concurrently. And for the purpose, quantitative evaluation method for machines, systems and processes of the microfactories are required first. However, the effect of the microfactory in reducing environmental impact and costs has not been examined quantitatively. If it is possible to show how microfactory can contribute to enhance the efficiency of the production systems, application area of the microfactory will greatly expand. So, as the first step of the quantitative evaluation of system design, this paper proposes a simple efficiency index based on the overall throughput, machine cost, labor cost, electricity cost, environmental impact measured by electrical power and material consumption. The proposed efficiency index is expressed by the equation, Ef=F/SQRT(C*E), where Ef is the efficiency index, F is the functionality of the system, C is the overall cost and E is the overall environmental impact. In the paper F is simply expressed by the throughput of the system. C is the sum of the labor cost, the machine cost and the electricity cost, and E is sum of equivalent CO2 exhaust of power consumption and materials for the machines. Using the abovementioned microfactory as an example, the paper tries to examine whether the proposed index is useful in evaluating and improving the system configuration. The calculation results indicate that there are some configurations that are more efficient than the others. The calculation also shows that efficiencies of miniature systems like the microfactory are not very less than those of conventional mass production systems, when the required throughput is not very high. The result leads us to conclude that the proposed efficiency index is useful in evaluating the system design. It also insists that microfactory-like systems are hopeful for future manufacturing systems in which high functionality, low cost and low environmental impact are required.Pages: 47-5

Impact of Separator Thickness on Temperature Distribution in Single Cell of Polymer Electrolyte Fuel Cell Operated at Higher Temperature of 90 °C and 100 °C

The New Energy and Industry Technology Development Organization (NEDO) road map (Japan, 2017) has proposed that a polymer electrolyte fuel cell (PEFC) system, which operates at a temperature of 90 °C and 100 °C, be applied for stationary and mobility usage, respectively. This study suggests using a thin polymer electrolyte membrane (PEM) and a thin gas diffusion layer (GDL), at the same time, to achieve better power-generation performance, at a higher temperature than usual. The focus of this paper is to clarify the effect of separator thickness on the distribution of temperature at the reaction surface (Treact), with the relative humidity (RH) of the supply gasses and initial operation temperature (Tini), quantitatively. In this study, separator thickness is investigated in a system using a thin PEM and a thin GDL. Moreover, this study investigates the difference between the maximum temperature and the minimum temperature obtained from the distribution of Treact as well as the relation between the standard deviation of Treact − Tini and total voltage, to clarify the effect of separator thickness. The impact of the flow rates of the supply gases on the distribution of Treact is not large, among the investigated conditions. It is noticed that the temperature distribution is wider when a separator thickness of 2.0 mm is selected. On the other hand, it is observed that the temperature increases along with the gas flow through the gas channel, by approximately 2 °C, when using a separator thickness between 1.5 mm and 1.0 mm. The impact of the RH on the distributions of Treact − Tini is larger at Tini = 100 °C, when a separator thickness of 1.0 mm is selected. It is revealed that the wider temperature distribution provides a reduction in power-generation performance. This study proposes that the thin separators, i.e., with a thickness of 1.5 mm and 1.0 mm, are not suitable for higher temperature operation than usual

LONGER SURVIVAL AND FEWER METASTASES BY LEVAMISOLE AND TEGAFUR IN 1, 2-DIMETHYLHYDRAZINE-INDUCED MURINE COLONIC CANCERS

The anticancer effects of levanisole, tegafur and their combination were experimentally compared in rats on the 1, 2-dimethylhydrazine (DMH)-induced colonic cancers. DMH at 20 mg/kg of body weight was injected subcutaneously to Donryu rats once a week for 24 weeks long. Nineteen weeks after the start of DMH administration, early colonic cancers were induced and, 28 weeks after, they developed into advanced cancers with distant metastases. From 19 weeks after the start of DMH injection, subcutaneous administration of levamisole at the dose of 2 mg/kg, oral administration of tegafur at 90 mg/kg and their combination were given to the rats daily for nine weeks. The animals were sacrificed 28 weeks after the start of DMH administration. Tegafur was effective, but levamisole with or without tegafur was not effective against early cancer. From 28 weeks after the start of DMH injection, levamisole, tegafur and their combination were administered to the rats daily for four weeks. All of the rats were necropsied when they died. The survival rate and mean survival days were significantly higher and longer in the levamisole groups than in the control rats (p<0.05). The incidence of distant metastases was also significantly lower in the levamisole groups than in the control group