Synthesis and characterization of cryogenic adhesives based on epoxy-modified polyurethane resin systems

Polyurethane adhesives containing the polyether backbone exhibit a good joint strength in cryogenic environments. In practice, many of the commercially available polyurethane adhesive systems contain free or chemically blocked isocyanates which have some limitations. This study presents the synthesis and characterization of a modified polyurethane type adhesive. Glycidol was used to convert the isocyanate-terminated polyurethane prepolymer to glycidylterminated polyurethane prepolymer. A series of glycidyl-terminated polyurethanes, based on polyoxypropylene glycol (PPG) soft segments having different molecular weights, were synthesized and their adhesive properties on aluminium were evaluated. The effect of the soft segment length on adhesion was examined. The adhesive properties at room temperature and cryogenic temperature are in line with the phenomenon observed in dynamical mechanical analysis (DMA) and in the phase separation behavior of the polyurethanes. Differential scaning calorimetry (DSC) was used to assess the phase separation content. An improvement in the adhesive strengths at room temperature is achieved by adding epoxy resins to the glycidyl-terminated polyurethane resins.     

New inverse kinematic algorithms for redundant robots

New inverse kinematic algorithms for generating redundant robot joint trajectories are proposed. The algorithms utilize the kinematic redundancy to improve robot motion performance (in joint space or Cartesian space) as specified by certain objective functions. The algorithms are based on the extension of the existing “joint-space command generator” technique in which a null space vector is introduced which optimizes a specific objective function along the joint trajectories. In this article, the algorithms for generating the joint position and velocity (PV) trajectories are extensively developed. The case for joint position, velocity, and acceleration (PVA) generation is also addressed. Application of the algorithms to a four-link revolute planar robot manipulator is demonstrated through simulation. Several motion performance criteria are considered and their results analyzed.     

A micro enzymic method for determination of choline-containing phospholipids in serum and high density lipoproteins

A micro method is described for the assay of choline-containing phospholipids in serum and high density lipoproteins (HDL) using an automated microtiter plate reader. The method is adapted from the enzymic method of Takayama, Itoh, Nagasaki, and Tanimuzu (Clin. Chim. Acta 79, 93–98, 1977) using phospholipase D, choline oxidase, and peroxidase coupled with the color generating system phenol and 4-amino-antipyrine. The micro method requires 5 μL of serum or HDL sample, and 42 samples can be assayed in duplicate in one run using a 96-well flat-bottom microtiter plate. The reaction is linear up to 400 mg/dL and the lower limit of detection is 0.25 mg of choline-containing phospholipids per assay. The coefficient of variation within an assay is 0.86–0.79%, and day-to-day variation is 0.9–1.5%. Results obtained by the micro method are in excellent agreement with those obtained by the procedure of Takayamaet al. (r=0.997). The supernatant left after removal of low density lipoproteins and very low density lipoproteins from serum and precipitation with heparin/manganese chloride reagent can thus be conveniently used for the micro assay of choline phospholipids in HDL.     

The cytotoxic activities of human hemoglobin and diaspirin crosslinked hemoglobin

It is well known that hemoglobin (Hb) possesses many oxidative enzyme activities, including a pseudo-peroxidase activity. It has also been shown by many investigators that various peroxidases in the presence of hydrogen peroxide and a halide ion exert a potent cytotoxic activity toward various mammalian cell types. It has further been observed by various investigators that the administration of relatively large amounts of purified Hb or a Hb derivative to a host animal during resuscitation experiments leads to a number of unrelated types of tissue damage and cell damage in the host. The first objective of this investigation was to determine if the observed tissue and cell damage may be due to a cytotoxic activity that Hb may exert in vivo analogous to that of the peroxidases. We also showed some time ago that peroxidases are able to activate peritoneal macrophages to the cytocidal state. Hence, we also addressed the question whether or not Hb is able to activate macrophages in a similar manner. Our results were negative with regard to both questions. Further investigations indicated that, unlike the peroxidases, ferryl-Hb is unable to oxidize iodide to iodine at a measurable rate, which appears to be the reason for the lack of cytotoxic activity.     

Camera position estimation and feature extraction from an incomplete image of a landmark

In the autonomous unmanned helicopter landing problem, the position of the unmanned helicopter relative to the landmark is very important. A camera carried on the unmanned helicopter can capture an image of the landmark. In earlier research, it was reported that the camera position could be estimated by features extracted from the landmark image. However, it is necessary that the landmark image should be complete, or with only slight deficiencies, in order for this estimation process to be possible. In this article, we report on an innovative design for an estimation made from a camera position giving an incomplete single image of the landmark. An adaptive neuro-fuzzy inference system (ANFIS) is used to construct the mapping relation between the features of complete and incomplete landmark images. It will be verified that it is possible to estimate the camera position from a landmark image more than half of which is defective via the proposed method.     

Directional Prediction CamShift algorithm based on Adaptive Search Pattern for moving object tracking

Moving object tracking is a fundamental task on smart video surveillance systems, because it provides a focus of attention for further investigation. Continuously Adaptive MeanShift (CamShift) algorithm is an adaptation of the MeanShift algorithm for moving objects tracking significantly, and it has been attracting increasing interests in recent years. In this work, a new CamShift approach, Directional Prediction CamShift (DP-CamShift) algorithm, is proposed to improve the tracking accuracy rate. According to the characteristic of the center-based motion vector distribution for the real-world video sequence, this work employs an Adaptive Search Pattern (ASP) to refine the central area search. The proposed approach is more robust because it adapts the optimal search pattern methods for the most adequate direction of the moving target. Since the fast Motion Estimation (ME) method has its own moving direction feature, we can adaptively use the most proper fast ME method to the certain moving object to have the best performance. Furthermore for estimation in large motion situations, the strategy of the DP-CamShift can preserve good performance. For the test video sequences with frame size of 320 × 240, the experimental results indicate that the proposed algorithm can have an accuracy rate of 99 % and achieve 23 frames per second (FPS) processing speed.     

Extraction equilibria and separation of phenylalanine and aspartic acid from water with di(2‐ethylhexyl)phosphoric acid

The distribution equilibria of single and binary L ‐phenylalanine and L ‐aspartic acid between water and a kerosene solution of di(2‐ethylhexyl)phosphoric acid (D2EHPA) were studied. It was shown that the distribution ratios of phenylalanine generally increased with increasing aqueous pH (2–5) in the D2EHPA concentration range 0.1–0.5 mol dm^?3, but those of aspartic acid decreased with increasing solution pH. Different reaction stoichiometries were proposed for the extraction of phenylalanine and aspartic acid under the conditions studied. The extraction equilibrium constants were obtained. Competitive extraction in binary systems was more apparent in the pH range where the cationic form of amino acids was not predominant. The present results indicated that selective separation of phenylalanine to aspartic acid was possible with this cationic extractant when they were extracted at higher pH and stripped using higher acidity of HCl solution. Copyright © 2006 Society of Chemical Industry     

Lighting-driven voxels for memory-efficient computation of indirect illumination

Several recently proposed voxel-based global illumination algorithms rely on the use of reflective shadow maps (RSMs) to interactively compute indirect illumination. However, RSMs do not scale well with the number of light sources because of their high memory consumption when rendering. Observing that, in most cases only a fraction of the voxels really contribute to single-bounce indirect illumination, in this paper we propose the use of lighting-driven voxels (LDVs), which are constructed from a subset of voxels, to reduce the memory burden. They are used in conjunction with a voxel-based global illumination algorithm that enables the interactive indirect illumination of dynamic scenes. We evaluate the memory usage, query performance, and construction speed for various voxel resolutions. Empirically, rendering with LDVs consumes an order of magnitude less memory than rendering with RSMs. Further, it achieves a higher performance for radiance queries when multiple light sources are used. Moreover, we integrated our method into voxel ray tracing and voxel cone tracing. For each of algorithm, we achieve an interactive performance that significantly reduces memory with respect to the reference solution.