Solving the irregular strip packing problem via guided local search for overlap minimization

The irregular strip-packing problem (ISP) requires a given set of non-convex polygons to be placed without overlap within a rectangular container having a fixed width and a variable length, which is to be minimized. As a core sub-problem to solve ISP, we consider an overlap minimization problem (OMP) whose objective is to place all polygons into a container with given width and length so that the total amount of overlap between polygons is made as small as possible. We propose to use directional penetration depths to measure the amount of overlap between a pair of polygons, and present an efficient algorithm to find a position with the minimum overlap for each polygon when it is translated in a specified direction. Based on this, we develop a local search algorithm for OMP that translates a polygon in horizontal and vertical directions alternately. Then we incorporate it in our algorithm for OMP, which is a variant of the guided local search algorithm. Computational results show that our algorithm improves the best-known values of some well-known benchmark instances.     

Local dimming light‐guiding plate type backlight system using alignment‐controlled polymer‐dispersed liquid crystals

A new technology which enables a local brightness control according to the displayed images has been expected in the thin and lightweight backlight systems to improve a contrast ratio and power consumption of the liquid crystal displays (LCDs). In this paper, we have proposed a novel local‐dimming backlight system using alignment‐controlled polymer‐dispersed liquid crystals as a light‐guiding plate and investigated the forming conditions of polymer‐dispersed liquid crystals to achieve both a high‐luminance ratio and a fast response speed. As a result, we found that a luminance ratio and response speed of the backlight system can be improved by using bifunctional LC monomer materials and forming fine and rigid polymer network in the LCs, and achieved high luminance ratio of 16:1 and fast response time less than 0.5 ms. In addition, we fabricated the twisted nematic‐mode LCD using the local dimming light‐guiding plate‐type backlight based on this design, and successfully realized eight times higher contrast ratio than that of the traditional twisted nematic‐mode LCD.     

Effects of heated seat and foot heater on thermal comfort and heater energy consumption in vehicle

Subjective experiments involving 12 different conditions were conducted to investigate the effects of heated seats and foot heaters in vehicles on thermal sensation and thermal comfort. The experimental conditions involved various combinations of the operative temperature in the test room (10 or 20°C), a heated seat (on/off) and a foot heater (room operative temperature?+10 or?+20°C). The heated seat and foot heater improved the occupant's thermal sensation and comfort in cool environments. The room operative temperature at which the occupants felt a 'neutral' overall thermal sensation was decreased by about 3°C by using the heated seat or foot heater and by about 6°C when both devices were used. Moreover, the effects of these devices on vehicle heater energy consumption were investigated using simulations. As a result, it was revealed that heated seats and foot heaters can reduce the total heater energy consumption of vehicles. Statement of Relevance: Subjective experiments were conducted to investigate the effects of heated seats and foot heaters in vehicles on thermal comfort. The heated seat and foot heater improved the occupant's thermal sensation and comfort in cool environments. These devices can reduce the total heater energy consumption in vehicles.     

Control of three-link underactuated manipulators using a switching method of fuzzy energy regions

In general, manipulators used for industry and in academic laboratories have actuators to drive each joint. On the other hand, underactuated manipulators handled by our research have some passive or free joints without actuators and brakes. We recently developed a switching method of fuzzy energy regions to control such manipulators. In such a method, it is necessary to design parameters related to energy regions and the gains of some partly stable controllers based on the computed torque method. Here, the switching method is applied for a three-link underactuated manipulator. We optimize such design parameters related to fuzzy energy regions by a genetic algorithm. The effectiveness of the present method is illustrated with some simulations. This work was presented in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January 25–27, 2007     

Response analysis for identifying the origin of photo-modulated current contrasts in scanning tunneling microscopic imaging semiconductor surfaces

Inhomogeneities in semiconductor solids can be imaged by two-dimensional mapping of the amplitude of periodically modulated tip current in scanning tunneling microscopy that is induced by illumination of semiconductor samples with a chopped light. It has been shown that it is possible to distinguish between plural origins of the photo-modulated current by analyzing the response properties of the current signal. A judicial choice of the modulation frequency is important for the required contrasts to be obtained.     

Effects of heated seats in vehicles on thermal comfort during the initial warm-up period

Eight subjects participated in a subjective experiment of eight conditions to investigate the effects of heated seats in vehicles on skin temperature, thermal sensation and thermal comfort during the initial warm-up period. The experimental conditions were designed as a combination of air temperature in the test room (5, 10, 15, or 20 °C) and heated seat (on/off). The heated seat was effective for improving thermal comfort during the initial warm-up period when air temperature was lower than 15 °C. Use of heated seats prevented decreases in or increased toe skin temperature. Heated seats also increased foot thermal sensation at 15 and 20 °C. Optimal thermal sensation in contact with the seat was higher when air temperature was lower. Optimal skin temperature in contact with the seat back was higher than that with the seat cushion. Moreover, these optimal skin temperatures were higher when air temperature was lower.     

A facile synthesis of hydro- and vinyl-functionalized di- and tetrasiloxanes and polyaddition via hydrosilylation

Summary Hydro- and vinyl-bifunctionalized di- or tetrasiloxane were synthesized by degradative cleavage of functional cyclic siloxanes with methyllithium followed by quenching with a functional chlorosilane, or by ring-opening of hexamethylcyclotrisiloxane (D₃) by functional alkyllithium followed by quenching with a functional chlorosilane. These bifunctionalized siloxanes were used as monomers in polyaddition with transition metal catalysts.     

Formation of Zirconia Solid Solutions Containing Alumina Prepared by New Preparation Method

In the system ZrO₂–Al₂O₃, a new method for preparing ZrO₂ solid solutions from ZrCl₄ and AlCl₃ using hydrazine monohydrate is investigated. c -ZrO₂ solid solutions containing up to ∼40 mol% Al₂O₃ crystallize at low temperatures from amorphous materials. The formation mechanism is discussed from IR spectral data. The values of the lattice parameter α increase linearly from 0.5072 to 0.5105 nm with increasing Al₂O₃ content. At higher temperatures, transformation of the solid solutions proceeds as follows: c ( SS ) → t ( ss ) → t ( ss ) +α-Al₂O₃→ m +α-Al₂O₃. m -ZrO₂–α-Al₂O₃ composite ceramics are fabricated by hot isostatic pressing for 2 h at 1250°C and 196 MPa. Microstructures and mechanical properties are examined, in connection with increasing Al₂O₃ content.     

Agglomeration control of hydroxyapatite nano-crystals grown in phase-separated microenvironments

Materials synthesis processes that require high temperatures consume large quantities of energy that generate an environmental burden. We attempted to synthesize hydroxyapatite (HAp) nano-crystals without firing or melting. “Water in oil” (W/O) emulsions were employed as microreactors for HAp formation. The surfactant-bounded water mediated HAp crystal nucleation, and HAp nano-crystallites were obtained. The obtained particles were aggregates composed of plate-like nano-crystals and monodisperse tiny crystals. Utilization of the W/O emulsions resulted in tunable nucleation frequency and the reactant provision, and yielded HAp nano-crystals with characteristic agglomeration properties.