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Showing papers in "International journal of the Society of Materials Engineering for Resources in 2010"


Journal ArticleDOI
TL;DR: In this article, the authors try to reply to the main idea on the arena of sustainable construction discussed as the research area, which is the beneficial integration of separate idea into new concept, which could provide for sustainable development of human being.
Abstract: The leitmotiv of the renoma ICMR Akita International Conference since 1991 is the beneficial integration of separate idea into new concept, which could provide for sustainable development of human being. Authors try to reply to this Conference main idea on the arena of sustainable construction discussed as the research area. The notion of sustainable development aspires to the role of a leading civilisational idea. Sustainable development \"implies meeting the needs of the present without compromising the ability of future generations to meet their own needs\" (UN, 1987) [1]. The term is the most frequently found expression in forecasts and similar studies. It follows from philosophical premises and-in Poland-it is a constitutional prerequisite: \"The Republic of Poland shall safeguard the independence and integrity of its territory and ensure the freedoms and rights of persons and citizens, security of citizens, safeguarding of Poland's national heritage, and ensure the protection of the natural environment pursuant to the principles of sustainable development.\" Therefore, sustainable development constitutes a principle that is to be followed by the Republic of Poland, in turn safeguarding fundamental values. In the Environmental Protection Laws, the definition of sustainable development is expanded further: such socio-economic development, in which-in order to equalise the opportunities to access the environment by individual communities or their members-both of contemporary generations and those still to come-a process of the integration of political, economic, and social actions takes place, maintaining the natural balance and continuity of vital natural processes [2]. Brundtland's definition of sustainable development [1] points out some ethical and ecological aspects. Cywiński, in his philosophy of sustainability [3], underlines the need to generalise the definition of sustainable development and to also consider human spiritual needs. According to Cywi.ski, sustainable development fulfils the comprehensive, spiritual, and material needs of today's people, without limiting the ability of future generations to satisfy their own respective needs. As a consequence, engineers must be prepared to respond not only to the 'material' question of 'how' but also be able to successfully cope with the 'spiritual' challenges of 'why'. [4]. The principle of sustainable development can also be approached from the point of view of the caution that is included in the second law of thermodynamics. In Clausius'version, the law implies that in isolated systems, processes can only occur if entropy is increased at the same time. There have always been civilisations that have declined and fallen. In our times, the imperative of the constant growth of scale and sophistication might also bring about a disaster. Daly [5] formulated the following general principles of sustainability (Table 1): renewable resources (e.g. water), including food (e.g. fish), must not be used faster than the rate at which they can be regenerated, non-renewable resources must not be used faster than they are replaced with renewable substitutes, pollution and waste must not be produced faster than they can be absorbed by nature, recycled, or rendered harmless. Sustainable development is a life necessity. The above summary reflects a general research inspiration, comprising such areas in construction as the rationalisation of energy management (energy + mass), structural durability, maintenance, renovation, repairs, modernisation (including revitalisation), working life, Sustainable Construction as a Research Area

56 citations


Journal ArticleDOI
TL;DR: In this article, the authors reported the first synthesis of TC[6]A-CH2CONEt2 (1) and TC[ 6] A-CH 2SCOCH3 (2) derivatives from rare metal mixed solution.
Abstract: Thiacalixarenes (TC[n]As), which are new members of the calixarene (C[n]As) family are very promising molecules with many potential applications in supramolecular chemistry . From an environmental and economical point of view, there remains a need to design more selective and effective extractants for toxic and valuable metals from waters and soils. The challenge is to find ligands that selectively extract commercially useful metals from mixtures and allow them to be released in pure form . C[n] As and TC[n]As and their derivatives can be used as receptors to recognize a wide variety of ions and organic molecules, forming host-guest or supramolecular complexes . Considerable attention has been recently focused on TC[n]As because there are many features that are not presented in chemistry of C[n]As [4] of which bridging sulfide moieties, which may be capable of extensive metal coordination. The complexation ability of the thiacalix[4] arene(TC[4]A) towards neutral molecules or metal ions has also been investigated . However, to our best knowledge, there are few reports on molecular extraction system including organic and inorganic compounds by modified TC[6]A and TC[6] A itself . It is because that the synthesis of TC[6]A is still hard because the synthetic yield is very low . Precious metals are important materials in many industrial fields. Platinum-group metals belonged in precious metals are important because they are used as catalyst materials, especially as an automotive catalyst. It is well known that three-way catalyst (TWC), which was composed of PGM such as platinum (Pt), palladium (Pd) and rhodium (Rh), can reduce more than 99% of emission of autoexhaust . The TC[4]A-CH2CONEt2 shows significant complexation of many cations with maximal level . Sulfur containing calixarenes, which are TC[n]As, are an important class of compounds because they can be used for selective extraction of soft heavy metal ions against alkali, alkaline earth, or other common metal ions . CnAs with sulfur-derivatized functionalities potentially meet these requirements because they are multidentate preorganized macrocyclic ]type ligands with appended arms . Herein we report the first synthesis of TC[6]A-CH2CONEt2 (1) and TC[6] A-CH2SCOCH3 (2), which is sulfur containing TC[6]A derivative). It should be emphasis on that a larger TC[6]A (3) derivatives were a more flexible ligand than that of the corresponding TC[4] A derivative. The structures of these compounds are abbreviated in Scheme 1. In this contribution, we would like to report the Selective Extraction Ability of Thiacalix[6]arene Derivatives from Rare Metal Mixed Solution

13 citations


Journal ArticleDOI
TL;DR: In this paper, three different types of incineration ash, coal fly ash, and paper sludge fly ash (PSFA), were converted into useful materials using the alkali fusion method.
Abstract: Conversion of three different types of incineration ash, coal fly ash (CFA), paper sludge fly ash (PSFA) and industrial waste incineration fly ash (IWIFA) into useful materials using the alkali fusion method is attempted. The chemical and mineralogical compositions of these ashes differed. The order of Ca content in the ash was IWIFA>PSFA>CFA, while the Si and Al contents in the ashes were CFA>PSFA>IWIFA. CFA was mainly composed of quartz [SiO2] and mullite [3Al2O3·2SiO2], PSFA mainly of gehlenite [Ca2Al2SiO7], anorthite [CaAl2Si2O8] and talc [Mg3Si4O10(OH)2], and IWIFA mainly of portlandite [Ca(OH)2], halite [NaCl] and sylvine [KCl]. Zeolites (zeolite-X, -A, -P and hydroxysodalite), hydrogrossular (katoite), and calcite were synthesized from the ashes. With an increasing Ca content of the ash, the Si concentration in the solution decreased, and the main product phases changed from zeolite (aluminosilicate) to hydrogrossular (calcium aluminosilicate), and finally to calcite (calcium carbonate). The observed concentrations of Si, Al, and Na in the solution during the reaction explain the crystallization of these phases.

10 citations


Journal ArticleDOI
Kazuhiko Imano1
TL;DR: In this article, the mode conversion of Lamb waves in the aluminum plate and its possible use in NDE is discussed and an experimentally observed model of the propagation of Lamb wave in an aluminum plate of varying thickness is presented.
Abstract: Ultrasonic waves are frequently used in the pulse-echo and pulse transmission methods for the detection of defects. Recently, plate waves have been employed in the nondestructive evaluation (NDE) of materials . Guided waves such as Lamb waves have the unique feature of propagating a great distance in plates and cylindrical structures. In Lamb wave measurements, defects in a material can be detected with one propagation measurement rather than pointby-point measurements. Novel guided wave measurement systems employing Lamb waves or Rayleigh waves have been constructed; e.g., a tilted angle polarization-type piezoelectric transducer for plate wave generation and a NDE system for a pipe or a plate that uses air-coupled ultrasonic waves in the megahertz range. The propagation of Lamb waves in a plate is affected by the thickness d of the material and the wave frequency f. Propagation behavior in a plate having varying thickness, which models abrasion, wear or wall reduction, might be useful to obtain information about defects. However, the behavior of Lamb waves at the plate edge and the defect are considered to be very complex, so that the experimental research into Lamb wave propagation in plates of varying thickness has only been reported. However, theoretical study of mode conversion of Lamb waves in plate at defects has not been established. The propagation of Lamb waves in a plate of varying thickness is important for the NDE of properties such as wear, abrasion and corrosion-induced wall reduction. In this paper, the propagation of Lamb waves in an aluminum plate of varying thickness is experimentally observed using optical system. The mode conversion of Lamb waves in the aluminum plate and its possible use in NDE are discussed. 2. Propagation of Lamb waves

10 citations


Journal ArticleDOI
TL;DR: In this paper, the authors have developed a new process to minimize the production of excess sludge with the ferrite particles, which can be used to reduce the burden on the environment.
Abstract: Wastewater from house is taken under WWT process and treated water is removed to the nature. Biological analysis method using activated sludge is well known and used method for its cheap running cost. But, a large number of excess sludge is produced in the WWTPs which is a great burden in both economical and environmental aspects. Figure 1 is an example of annual industrial waste of Japan [1]. About 75,073,000 ton of activated sludge related to industrial waste was to be treated in 2004 in Japan. It is not only a headache of Japan, but to the rest of the world. Many research works are being carried out for the process of excess activated sludge [2-6]. However, recently, a new approach has been started to minimize this excess sludge. A part of activated sludge is treated under cell lysis. The treated sludge or a part of the treated sludge becomes to be equal to biological waste. This treated sludge is sent to the aeration tank and is decomposed by the non-treated activated sludge and thus the excess sludge can be minimized. Several reports regarding cell lysis in order to reduce excess sludge are published including ozonation, milling process with beads, revolving disks methods etc. [2-10]. However, the methods are still on the process and a new and effective technology method is still a demand in this new branch. We have developed a new process to minimize the production of excess sludge with the ferrite particles. This magneto-ferrite method was explained in other papers [11, 12]. Ferrite particles are kept with activated sludge in a test tube and the test tube is exposed to the magnetic flux. The ferrite particles are gathered together in the magnetic flux and they are scattered when they are out of the magnetic flux. Collisions occurred with ferrite particles and sludge which may lead to the cell lysis. The two miniature WWTPs were run for a fixed period of time with CAS and EA process [11, 12]. Magnetoferrite effect was applied for about 4 weeks in the case of CAS and found about 42% of excess sludge reduction with magneto-ferrite treatment of sludge comparing to the non-treated sludge. For EA method, it was continued for about 10 weeks and found no significant evidence of excess sludge in the treated aeration tank [12]. These two types of running processes for the WWTPs proved the effectiveness of the magneto-ferrite system in order Reduction of Excess Activated Sludge by Ferrite Particles : Methods for Practical Use

8 citations



Journal ArticleDOI
TL;DR: In this paper, a pressure gauge composed of PVDF sensing element which has longer recording time compare with manganin pressure gauge was developed to measure detonation pressure of non-ideal explosive which has long reaction zone length.
Abstract: Manganin pressure gauge has been widely used for pressure measurements of shock wave in condensed matter and detonation in condensed explosive. However, recording time of manganin gauge is limited to a few microsecond. This short recording time is not long enough to measure detonation pressure of non-ideal explosive which has long reaction zone length. We developed pressure gauge composed of PVDF sensing element which has longer recording time compare with manganin pressure gauge. In this study, detonation pressure profile was measured by PVDF pressure gauge for non-ideal explosives consisted of a packed bed of aluminum particles of different size saturated with neat nitromethane. The results of pressure measurements by PVDF pressure gauge show the existence of the extended pressure peak behind leading shock wave, and revealed important pressure increase due to aluminum particle reaction when aluminum particle size is smaller than 14 micrometer. The result of this study showed that PVDF pressure gauge is very useful tool to measure detonation pressure of non-ideal explosives which have very long reaction zone length.

8 citations



Journal ArticleDOI
TL;DR: In this article, a Pt thin film and two kinds of Pt oxide thin films prepared by reactive sputtering were characterized by XRD, XPS and EPMA, then their methanol oxidation activities were investigated using the rotating disk electrode method in a (H2SO4+CH3OH) solution.
Abstract: Methanol oxidation is the anodic reaction in a direct methanol fuel cell (DMFC). The development of a new catalyst, which can efficiently promote the anode reaction, is very important. In this study, a Pt thin film and two kinds of Pt oxide thin films prepared by reactive sputtering were characterized by XRD, XPS and EPMA, then their methanol oxidation activities were investigated using the rotating disk electrode method in a (H2SO4+CH3OH) solution. The Pt, PtO and PtO2 thin films were obtained by sputtering a Pt target in 100% Ar, Ar - 50% O2 and 100% O2 plasma, respectively. Neither PtO nor PtO2 had an excellent activity when the thin films were used as-received. However, an apparent catalytic activity of methanol oxidation was observed in the partially reduced Pt oxide thin films, whose ratios of O/Pt were significantly decreased by passing a cathodic current. On the other hand, the methanol oxidation activity of the Pt thin film was hardly changed by the electrochemical reduction. The methanol oxidation current showed that the electrocatalytic activity of the partially reduced Pt oxide thin films was about hundred times higher than that of the Pt thin film. Therefore, the partially reduced Pt oxide is a material with a significant potential for use as a catalyst for not only the DMFC, but also a fuel cell using the carbon compound as the fuel.

5 citations


Journal ArticleDOI
TL;DR: In this article, the applicability of waste gypsum board paper instead of paper debris was experimentally investigated and it was found through the unconfined compression tests that the failure strength and failure strain of modified soils by using crushed board paper are almost the same as those of modified soil by using paper debris.
Abstract: We have already developed a new recycling system for high water content mud such as construction sludge by using paper debris (fragments of the newspaper) to increase the recycling rate of the construction sludge. However, recently, the price of old newspaper is increasing. Therefore, development of inexpensive fiber materials are strongly desired in order to reduce the recycling cost. In this study, the applicability of waste gypsum board paper instead of paper debris was experimentally investigated. The waste gypsum board paper was crushed by the hammer mill and crushed paper was used in fiber-cement-stabilized-soil method. It was found through the unconfined compression tests that the failure strength and failure strain of modified soils by using crushed board paper are almost the same as those of modified soils by using paper debris. That is, it was confirmed that the crushed board paper can become a substitute of paper debris.

4 citations


Journal ArticleDOI
Gjergj Dodbiba1, I-Chen Wu1, Yu-Chen Lee1, Seiji Matsuo1, Toyohisa Fujita1 
TL;DR: In order to remove molybdenum (Mo) from the high-level radioactive liquid waste (HLLW), Pb-Fe based adsorbents were synthesized and their adsorption capacities were investigated.
Abstract: In order to remove molybdenum (Mo) from the high-level radioactive liquid waste (HLLW), Pb-Fe based adsorbents were synthesized and their adsorption capacities were investigated The adsorbent precursors were prepared with precipitation at various pH values by adding sodium hydroxide into a mixture of 1 mol/L lead nitrate and 1 mol/L ferric nitrate aqueous solutions, and each precipitate was then filtered, dried and ground to obtain a fine powder precursor The precursors were also calcinated at various temperatures to obtain the Pb-Fe based adsorbentsTwo main parameters were considered when synthesizing the adsorbents, ie the pH value of precipitation of adsorbent precursor as well as the calcination temperature of the Pb-Fe based adsorbent The experimental results indicated that the calcination temperature has a great influence on adsorption capacity of the Pb-Fe based adsorbent for Mo It was found that when the precursor was precipitated at pH 9 and then calcinated at 500 °C, the sorbed amount of Mo by the adsorbent was the highest In addition, the equilibrium sorption isotherm of Mo onto the adsorbent was estimated by the Langmuir, Freundlich and Redlich-Peterson sorption models We found that the overall adsorption process was described well by Redlich-Peterson sorption isotherm equation


Journal ArticleDOI
TL;DR: In this paper, a dry magnetic separation process was used to concentrate MgCr2O4, which will improve the grade of Pt and Pd associated with the flotation tailing obtained from UG-2 and Merensky projects to be offered as additional resource.
Abstract: Platinum group metals (Pt, Pd, Rh) are widely used in many applications such as catalyst, jewellery, auto-atalyst, and as demand continues to grow, the need to source these important metals from additional sources such as low grade deposits, industrial wastes, former mine and process tailings will increase. South Africa, the largest producer of platinum group metals, still has more than two thirds of the world's platinum reserves, at the same time it also has millions of tonnes of process tailings resulting from the mining and processing, mainly flotation tailings. PGMs are usually associated with chromite and has been known since the early 1920s [1,2]. Detail studies of this reef by the following researchers ; McLaren and De Villiers [3], Von Gruenewaldt et al., [4] and Gain [5] has also shown the association of PGMs and chromite. The UG-2 and Merensky ores are the main sources of PGMs in South Africa, the Merensky ore has less chromium compared to the UG-2 known to contain about 10% chromite, meaning that most of the PGMs lost in process tailings such as flotation are contained in chromite gangue [6-15]. In a recent study, the recovery of PGMs from the same tailings by flotation has been reported and the process showed Pt and Pd could be concentrated to over 45 g/t [6]. In this work we performed a dry magnetic separation process to concentrate MgCr2O4, concentrating MgCr2O4 will improve the grade of Pt and Pd associated with the flotation tailing obtained from UG-2 and Merensky projects to be offered as additional resource.

Journal ArticleDOI
TL;DR: In this article, the authors designed a new laboratory permeability test using low-cost apparatus and investigated its performance using a variation of the falling head method, in which the standpipe used as the pressure source is replaced with a pressure accumulator.
Abstract: The permeability of rock matrices is not routinely measured because the equipment is expensive and the measurements are time-consuming. We designed a new laboratory permeability test using low-cost apparatus and investigated its performance. The method is a variation of the falling head method, in which the standpipe used as the pressure source is replaced with a pressure accumulator. High pressure is applied to a rock specimen, making it possible to measure permeability within an hour. The apparatus produces radial flow from the surface to a central hole drilled in a cylindrical specimen. We determined that the apparatus measures hydraulic conductivity in the range of 3.5×10-10 to 2.6×10-4 cm/s. The error in hydraulic conductivity obtained from repeated measurements is ±∼10%, and the difference in conductivity between this method and the standpipe method is ∼25%. For a rock with a hydraulic conductivity of 3.0×10-9 cm/s, measurement takes at least 800 s.


Journal ArticleDOI
TL;DR: In this article, a simple but practical model was developed to predict heat flux variations with various waveforms of the imposed magnetic field, using the assumption of a one-dimensional heat source.
Abstract: Plasma arcs have been widely used for cutting or welding metals because they can supply a dense energy flow in a small area of an arc spot. However, it is not a convenient heat source to treat a wide area. To expand a plasma arc, various trials have been attempted [1], [2], [3], [4]. Takeda et al. [3], [4] developed a magnetically driven arc by imposing an alternating magnetic field perpendicular to a transferred arc. The arc oscillates because of the interaction between the electric arc current and the external magnetic field. Typical plasma arc profiles are presented in Figure 1. An arc in no magnetic field, as shown in Figure 1(a), deforms to a DC magnetic field, as portrayed in Figure 1(b). By imposing an AC magnetic field, the arc oscillates as depicted in Figure 1(c). For practical applications of such a magnetically driven arc, precise understanding of the heat flux distribution is necessary. Experimental observation by T. Yamamoto et al. [5] revealed that the heat flux decreased near the edge of the oscillatory amplitude. T. Toh et al. [6] has attempted to predict the heat flux distribution theoretically using a 3D MHD model. The present study develops a simple but practical model to predict heat flux variations with various waveforms of the imposed magnetic field, using the assumption of a one-dimensional heat source.

Journal ArticleDOI
TL;DR: An activated carbon with a high microporosity and mesoporosity, as well as a high bulk density, was fabricated by activating the extrusion-molded precursor made from carbonized rice husk (RH) and beet sugar (BS) at 850°C in CO2 as discussed by the authors.
Abstract: An activated carbon with a high microporosity and mesoporosity, as well as a high bulk density, was fabricated by activating the extrusion-molded precursor made from carbonized rice husk (RH) and beet sugar (BS) at 850°C in CO2 The pore structure of the activated carbon based on the mixture of RH and BS (RHBSAC) was analyzed in relation to the bulk density The extrusion molding was very useful to increase the bulk density RHBSAC which was first activated for 1 h was immersed again in the BS syrup and then activated in CO2 for 2 h This two-step activation process provided both a high bulk density (093 g/cm3) and a microporous and mesoporous structure (BET specific surface area: 844 m2/g, total pore volume: 053 cm3/g, micropore volume: 029 cm3/g, and mesopore volume: 019 cm3/g)





Journal ArticleDOI
Dan-qing Yi1, Mingzhe Zhou1, Huiqun Liu1, Bin Wang1, Sheng Yang1 
TL;DR: In this article, the effect of temperature and environment (air, humidity and 3.5 wt% NaCl salt spray) on cyclic fatigue life and fracture mechanism on 2524 aluminum alloy was investigated by scanning electron microscopy (SEM), TEM and fatiguae property testing.
Abstract: The effect of temperature and environment (air, humidity and 3.5 wt% NaCl salt spray) on cyclic fatigue life and fracture mechanism on 2524 aluminum alloy was investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and fatiguae property testing. The results showed that temperature has a detrimental influence on cyclic fatigue life. The cyclic fatigue strength n=106 at elevated temperature (100%°C) decreased by 30 MPa compared to that at cryogenic temperature (-55°C). Moreover, temperature also remarkably affected the feature of dislocation, second-phase particles and grain boundary. The fracture surface at cryogenic temperature showed crystallographic morphology. The dominant deformation process at ambient and elevated temperature was a combination of predominantly transgranular and local intercrystalline fracture mechanism. The fractographic features revealed the fatigue crack growth behavior of the alloy in three environments, more brittle striations were observed in humidity air and salt spray. The increased crack growth rate was attributed to a combination of hydrogen embrittlement and anodic dissolution at the tip of crack.

Journal ArticleDOI
TL;DR: In this paper, the effects of the operational conditions in the SC-mill such as rotor speed, grinding time, the mass of the grinding media, and the feed sample on the fine grindability of limestone were investigated for 0.5 and 0.8mm grinding media.
Abstract: This study presents results from a study of fine grinding in limestone conducted using a super centrifugal mill (SC-mill), a type of circular stirred mill. The effects of the operational conditions in the SC-mill such as rotor speed, grinding time, the mass of the grinding media, and the mass of the feed sample on the fine grindability of limestone were investigated for 0.5 and 0.8mm grinding media. The results suggest that the mass and the specific surface area of the fine particles produced by the SC-mill could be expressed as functions of the operational conditions mentioned above for the respective grinding media size.


Journal ArticleDOI
TL;DR: In this paper, the origin and transportation course of heavy metal elements were discussed for PMfine and PMcoarse, determined by using PIXE (Particle Induced X-ray Emission) and back trajectory analyses.
Abstract: Particulate matter (PM) was collected at the Hachimantai mountain range in northern Japan. In the present study, the origin and transportation course of the heavy metal elements were discussed for PMfine and PMcoarse, determined by using PIXE (Particle Induced X-ray Emission) and back trajectory analyses. The result shows that the PMfine emitted mainly from artificial sources, compared with the PMcoarse from natural sources, since the Enrichment Factor (EF) value and S/K ratio of PMfine was one order higher than that of PMcoarse. The origin of Pb in PM at Akita Hachimantai mountain range has both of the anthropogenic and the metal refining origins, using the analysis of Pb/Br. Furthermore, from result of back trajectory analysis when the air mass was transported over the Japanese Islands, the air mass was mainly passed over the large-scale industrial area in Japan. The origin of As and Se were mainly gasoline and coal combustion, and were transported from Chinese continent and/or Korea peninsula. NMCC ANNUAL REPORT 16 (2009)

Journal ArticleDOI
TL;DR: In this paper, a series sampling by constant volume (50 mL) continuously from occurrence to disappearance of radiation fog at Takanosu Basin was performed to clarify the pollution mechanism of fog by fumigation and showed that the absolute equivalent of pollutants in fog water such as (NH4)2SO4 and NaCl for eight events increased during the early morning, immediately before the disappearance of fog.
Abstract: When an inversion layer forms, particulate matter (PM) stagnates in the upper part of the inversion layer. The PM falls to the ground as an inversion layer collapses. This phenomenon generally called fumigation. We sampled radiation fog by constant volume (50 mL) continuously from occurrence to disappearance of radiation fog at Takanosu Basin to clarify the pollution mechanism of radiation fog by fumigation. Our results show that the absolute equivalent of pollutants in fog water such as (NH4)2SO4 and NaCl for eight events increased during the early morning, immediately before the disappearance of radiation fog. Using the series sampling by constant volume of the radiation fog, it was clarified that the increase in pollutant of air by fumigation results in the increase of pollutant in fog droplets.


Journal ArticleDOI
TL;DR: In this article, the authors examined the effects of ultraviolet light on the mechanical and electrical characteristics of polylactic acid (PLA) in order to clarify the prospects of using PLA as an electrical insulator material.
Abstract: Polylactic acid (PLA) is a biodegradable, eco-friendly plastic that is attracting more attention than any other plastic of its kind. In this study, the authors examined the effects of ultraviolet light on the mechanical and electrical characteristics of PLA in order to clarify the prospects of using PLA as an electrical insulator material. An examination of the tensile stress curves versus the elongation showed that the stress and elongation of PLA decreased with an increase in the time length of the UV irradiation and that this decrease in the elongation was significant. The authors found that the dielectric breakdown strength (EB) is temperature dependent; that is, with an increase in the time length of the UV irradiation, the EB of PLA had a tendency to decrease over a wide temperature range.

Journal ArticleDOI
TL;DR: The needs for new display materials of computer graphics, and new 2D and 3D displays, are stressed in this paper.
Abstract: Nowadays computer graphics are getting widely used. The fundamental algorithms of computer graphics are the basis of graphical systems. They are called repeatedly in each graphical application, so the efficiency of them is very important. These algorithms have been researched for a long time, so it is difficult to get even a little progress. Mathematicians have demonstrated that the best disposition of a discrete set of points on the plane can be reached if the points are on a hexagonal grid. In recent years, studies by scientists in computer graphics and image processing have shown the advantages of the hexagonal grid over the square grid. Many applications need new functions of computer graphics, and new 2D and 3D displays. In this paper, we stress on the needs for new display materials.