Switchgear component commonality design based on trade-off analysis among inventory level,delivery lead-time and product performance

The shortening of product delivery lead-times can usually be achieved by keeping high-level components in inventory, however in small-volume production systems, maintaining such inventories is often a costly as well as a risky business strategy. If the risk of maintaining unsold inventory can be decreased, even small-volume manufacturers may be able to justify holding more significant quantities of versatile inventory. This paper discusses a component commonality effect to breakthrough the trade-off relationship between inventory levels and delivery lead-times for such small-volume production systems. By using the same component in different products, inventory maintenance costs can be dramatically reduced, but component commonality design problems are inherently complex, since excessive module commonality may lead to lower product performances, and there are trade-off relationships between product performance and cost reductions obtained through component commonality. In this paper, such a design problem is formulated as a multiobjective component commonality design optimisation problem considering inventory level, delivery lead-time and product performance, and the optimal solutions are obtained as a Pareto optimal solution set. Detailed procedures concerning the proposed design method, including inventory simulation, are discussed and developed for a switchgear design problem. Finally, an example switchgear design problem is solved to illustrate that optimal use of component commonalities across different modules can significantly reduce inventory costs, while also shortening product delivery lead-times.     

Promotion of Adventitious Roots in Chrysanthemum Cuttings by Soaking in Ozonated Water

To examine the effect of soaking in ozonated water (OW) on development of adventitious roots, basal ends of chrysanthemum cuttings (Chrysanthemum morifolium Ramat.) were soaked in 1, 3 or 5 mg L^?1 OW, in an indol-3-butyric acid (IBA) solution prepared from a commercial root promoting agent or in distilled water (DW). At 20 day after transplanting (DAT), a significant increase in adventitious root number (ARN) was observed in the IBA-treated cuttings but early root elongation was delayed. When soaked in the 5 mg L^?1 OW, ARN and total root length (TRL) grown over 40 mm were increased with a decrease in soaking duration (from 50 to 5 min). Lateral root number (LRN) of the cuttings soaked in the 3 mg L^?1 OW for 1 h showed four times higher than that of the DW treatment at 19 DAT. Optimal combination of dissolved ozone concentration and soaking duration can promote early root elongation and LRN of chrysanthemum cuttings. From a comprehensive standpoint, a high DOC of OW with a short soaking duration (3 mg L^?1 × 1 h and 5 mg L^?1 × 5 min) worked as well as IBA for adventitious rooting of chrysanthemum cuttings. These findings indicate that ozonated water can be an alternative to root promotion agents for adventitious rooting of chrysanthemum cuttings.     

Internet-Based Teaching and Experiment System for Control Engineering Course

e-Learning engineering courses with online experiments are attracting a great deal of attention because of the flexibility they provide in both teaching and learning. This paper has described an Internet-based teaching and experiment system for control engineering (ITESCE) that provides students with online course material, a simulator, an online control experiment using an arm robot, and the ability to store and search simulation and experimental results. To implement the functions required by the course and to facilitate connection to the Internet, the ITESCE is based on a standard browser/server architecture with three layers and employs multithreading, Java applets, and Java database connectivity. Background control subsystems handle the real-time control of experiments, and a network server handles communication with clients and with background control subsystems. A database stores simulation and experimental results. The course covers a variety of control methods, and students can try them out through online simulations and experiments. To enhance realism, a Web camera takes a video of an experiment and streams it to a student's PC in real time.     

Crystallographic Analysis of Fatigue Crack Initiation Behavior in Coarse-Grained Magnesium Alloy Under Tension-Tension Loading Cycles

Plane bending fatigue tests are conducted to investigate fatigue crack initiation mechanisms in coarse-grained magnesium alloy, AZ31, under the stress ratios R = ?1 and 0.1. The initial crystallographic structures are analyzed by an electron backscatter diffraction method. The slip or twin operation during fatigue tests is identified from the line angle analyses based on Euler angles of the grains. Under the stress ratio R = ?1, relatively thick tension twin bands are formed in coarse grains. Subsequently, compression twin or secondary pyramidal slip operates within the tension twin band, resulting in the fatigue crack initiation. On the other hand, under R = 0.1 with tension-tension loading cycles, twin bands are formed on the specimen surface, but the angles of those bands do not correspond to tension twins. Misorientation analyses of c-axes in the matrix grain and twin band reveal that double twins are activated. Under R = 0.1, fatigue crack initiates along the double twin boundaries. The different manners of fatigue crack initiation at R = ?1 and 0.1 are related to the asymmetricity of twining under tension and compression loadings. The fatigue strengths under different stress ratios cannot be estimated by the modified Goodman diagram due to the effect of stress ratio on crack initiation mechanisms.     

Effect of ITO surface treatment on organic light emitting diodes

Performance of organic light emitting diodes with structure of ITO/NPB/NPB:Ir(piq)3/Alq3/Al was studied by inserting MoO3 hole injection layer (HIL) and using differently cleaned indium tin oxides (ITOs). High luminance and quantum efficiencies were obtained using HIL and highly cleaned ITO. High power efficiency was obtained using HIL and conventionally cleaned ITO, while low driving voltage was obtained using highly cleaned ITO without HIL.     

An efficient inverse analysis considering observation error to detect corrosion in concrete structures containing multilayered rebar

The present paper proposes an efficient inverse analysis to detect corrosion in concrete structures including multilayered rebar using the observation accuracy as prior information. The proposed method can efficiently detect the corrosion profile, including factors such as the number, shape, and location of multiple corroded areas from a potential distribution on a concrete surface using the boundary element method and a genetic algorithm. The detectable are of rebar corrosion is estimated for each rebar layer. The estimation can effectively limit a solution space to detect corrosion. Numerical simulations are performed in order to demonstrate the validity and efficiency of the proposed method.     

Photovoltaics Based on Hybridization of Effective Dye‐Sensitized Titanium Oxide and Hole‐Conductive Polymer P3HT

Here, the fabrication of quasi‐solid‐state TiO₂/dye/poly(3‐hexylthiophene) (P3HT) solar cells is reported, in which the dyes with oleophilic thienyl groups were employed and ionic liquid (IL), 1‐ethyl‐3‐methylimidazolium (EMIm) containing lithium bis(trifluromethanesulfone)amide (Li‐TFSI) and 4‐tert‐butylpyridine (t‐BP) are assembled with dyed TiO₂ surfaces. One of the devices gave a high conversion efficiency of up to 2.70% under 1 sun illumination. The excellent performance is ascribed to successful molecular self‐organization at interface of the dye molecules and P3HT, and to the efficient charge separation and diffusion acquired by introduction of the IL coupled with Li‐TFSI and t‐BP.     

Leaf-like dislocation substructures and the decrease of martensitic start temperatures: A new explanation for functional fatigue during thermally induced martensitic transformations in coarse-grained Ni-rich Ti-Ni shape memory alloys

During repeatedly imposed thermally induced martensitic transformations in Ti-Ni shape memory alloys, the martensite start temperature M_s decreases. This has been rationalized on the basis of a scenario where an increasing dislocation density makes it more and more difficult for martensite to form. However, it is not clear why dislocations which form because they accommodate the growth of martensite during the first cooling cycle should act as obstacles during subsequent transformation cycles. In the present work we use diffraction contrast transmission electron microscopy to monitor the formation of unique leaf-like dislocation substructures which form as the martensite start temperature decreases during thermal cycling. We interpret our microstructural results on the basis of a microstructural scenario where dislocations play different roles with respect to the propagation of a big martensite needle in one transformation cycle and the nucleation and growth of new martensite needles in the following cycles. As a consequence, chestnut-leaf-like dislocation arrays spread out in different crystallographic directions.     

The effect of the thermal decomposition reaction on the mechanical and magnetocaloric properties of La(Fe,Si,Co)13

We report on the influence of the Co content in the magnetocaloric system La(Fe,Si,Co)₁₃ on the thermal decomposition (TD) reaction, and subsequently on the magnetocaloric properties. In the course of the TD reaction, the magnetocaloric La(Fe,Si,Co)₁₃ phase reversibly decomposes into α-Fe(Co,Si) and the intermetallic LaFeSi phase, thus enhancing the mechanical properties and therefore the machinability of the compound. The addition of Co significantly speeds up the reaction kinetics. The optimum temperature range for the TD reaction was determined to be 973–1073 K, with the lower and upper limit at 873 K and 1173 K, respectively. With electron microscopy a lamellar microstructure has been found in the decomposed state, indicating a eutectoid-type phase reaction. The width of the lamellae is ～26 nm in LaFe₁₂Si and decreases with increasing Co content. Three-dimensional atom probe (3DAP) measurements show the enrichment of Co and Si in LaFeSi lamellae. We conclude that the addition of Co somehow decreases the lamellar spacing, which is the main reason for the enhanced TD kinetics. Finally, it is interesting to note that the highly ordered nano-scale mixture of strongly ferromagnetic α-Fe(Co) with the non-ferromagnetic phase induces a significant increase in coercivity, H_c. The shape anisotropy of the thin α-Fe(Co) lamellae yields a semi-hard permanent magnet with a coercivity of ～100 A cm^?1.     

A kinetic study on oxygen transfer between solid oxide phase of ZrO2·CaO and liquid metal phase of silver with the aid of electromotive force decay curves

An experimental method was developed to compare the rate of the metal-oxide interface reaction, O^2?=O+2e, with the rate of oxygen transfer in liquid metal. A direct current was supplied to cause the polarization of the galvanic cell, Air: Liquid Ag?O÷ZrO₂·CaO÷Liquid Ag?O: Air. The electromotive force decay curves were obtained at 1100°C immediately after the supply of the current was cut off. The degree of the polarization was increased by increasing the current and its duration time and by decreasing the area of metal-oxide interface. The absolute value of the electromotive forces was affected by the direction of oxygen transfer. The depolarization was accelerated by stirring the liquid silver. The shapes of decay curves were estimated with the rate controlling step at the first order interface reaction and at the nonsteady state diffusion of oxygen in liquid metal. From the shape of the measured decay curves and the stirring effect, it was concluded that the rate of the interface reaction is much more rapid than the rate of oxygen transfer in the liquid metal under the present experimental condition.