A class of adaptive model- and object-driven nonuniform sampling methods for 3-D inspection

Inspection of manufactured parts and assemblies often requires large amounts of information in the form of test probe point locations and large amounts of time to perform the inspection. By optimally locating the probe points it is possible to maintain inspection reliability using fewer test probes in a reduced amount of time. We have developed algorithms which use part model and manufacturing process information to generate an optimal probe-point location set for routine inspection in a modelbased, open-loop mode. An alternate set of adaptive algorithms that sequentially generates probe-point locations in an object-based, closed-loop mode characterizes a fault when one is detected. Test results show that the algorithms perform favorably on a large class of surfaces.     

Stability Analysis of a Simple-Structured Fuzzy Logic Controller

The stability analysis for the fuzzy logic controller (FLC) has widely been reported. Furthermore some researches have been introduced to simplify the design process of FLCs. One of them is to decrease the number of parameters representing the antecedent part of the fuzzy control rule. So we briefly explain a simple-structured fuzzy logic controller (SFLC) which uses only a single variable at the antecedent part of a fuzzy control rule. We analyze that it is absolutely stable based on the sector bounded condition. We expand a nonlinear controlled plant into a Taylor series about a nominal operating point. The fuzzy control system is transformed into a Lure system with nonlinearities. We also show the feasibility of the proposed stability analysis through a numerical example of a mass-damper-spring system.     

Electrochemical detection of DNA hybridization using biometallization

We demonstrate the amplified detection of a target DNA based on the enzymatic deposition of silver. In this method, the target DNA and a biotinylated detection DNA probe hybridize to a capture DNA probe tethered onto a gold electrode. Neutravidin-conjugated alkaline phosphatase binds to the biotin of the detection probe on the electrode surface and converts the nonelectroactive substrate of the enzyme, p-aminophenyl phosphate, into the reducing agent, p-aminophenol. The latter, in turn, reduces metal ions in solutions leading to deposition of the metal onto the electrode surface and DNA backbone. This process, which we term biometallization, leads to a great enhancement in signal due to the accumulation of metallic silver by a catalytically generated enzyme product and, thus, the electrochemical amplification of a biochemically amplified signal. The anodic stripping current of enzymatically deposited silver provides a measure of the extent of hybridization of the target oligomers. This biometallization process is highly sensitive, detecting as little as 100 aM (10 zmol) of DNA. We also successfully applied this method to the sequence-selective discrimination between perfectly matched and mismatched target oligonucleotides including a single-base mismatched target.     

Packaging of gold particles in viral capsids

In-vitro self-assembly conditions known to result in generating infectious virions have been used in vitro to reassemble bromovirus capsid proteins around negatively charged gold nanoparticles cores. We discuss here the optical properties (elastic light scattering) and the influence of the core size and of the functional moiety on the resulting virus-like particles. Our results indicate that the formation of a closed shell, as opposed to an amorphous protein coat, does occur and that the shell/core interactions can be tuned using different coatings on the nanoparticle core. Such studies may lead to real-time monitoring of viral traffic on the scale of a single virus, as well as to the possibility of chemical sensing along the intracellular and intercellular viral pathways and contribute to a better understanding of the virus transport and cellular compartmentalization.     

Assessing organic contaminants in fish: comparison of a nonlethal tissue sampling technique to mobile and stationary passive sampling devices

As concerns mount over the human health risks associated with consumption of fish contaminated with persistent organic pollutants, there exists a need to better evaluate fish body burdens without lethally sampling many of the important commercial and sport species of interest. The aim of this study was to investigate two novel methods for estimating organic contaminants in fish that are a concern for both fish and human health. The removal of fish adipose fins, commonly done in mark-recapture studies with salmonid species, was evaluated as a nonlethal sampling technique to estimate concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in flathead catfish (Pylodictis olivaris), relative to those found in muscle fillets of the same fish. We also assessed the efficacy of using poly(dimethylsiloxane) (PDMS) as a mobile passive sampling device (PSD) attached directly to wild flathead catfish for assessing location-specific exposure of the fish to waterborne contaminants. The results of this study have demonstrated for the first time that organic contaminant concentrations in adipose fin were highly correlated (R2 = 0.87) with muscle fillet concentrations, indicating that the adipose fin of certain fishes may be used to accurately estimate tissue concentrations without the need for lethal sampling. Moreover, mobile PSDs attached directly to fish and used here for the first time accurately estimated ultratrace concentrations of waterborne PCBs and OCPs without any apparent harm to the fish, indicating that there are no practical or physical barriers to the use of mobile passive samplers attached to aquatic organisms. Among the many practical implications of this research, two potential priority items include the analysis of organic contaminants in farm-raised and sport fish intended for human consumption, without the economic and population losses associated with lethally sampling fish to obtain tissues, and identifying specific areas where fish may be accumulating large portions of their contaminant burden.     

Flow of dilute suspensions of deformable ellipsoidal particles in a plane channel

The influence of the internal properties of deformable suspended particles on the flow of suspensions in plane channels is investigated.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 43, No, 4, pp. 560–565, October, 1982.     

Synergistic cooperation between phorbol ester and IFN-gamma for induction of nitric oxide synthesis in murine peritoneal macrophages

The role of protein kinase C (PKC) in the induction of nitric oxide (NO) synthesis in murine peritoneal macrophages was examined. Phorbol ester, a PKC activator, had no effect on NO synthesis by itself, whereas IFN-gamma alone had modest activity. When phorbol ester was used in combination with IFN-gamma, there was a marked cooperative induction of NO synthesis in a dose-dependent manner. This increase in NO synthesis was reflected as increased amount of inducible NO synthase (iNOS) mRNA, as determined by Northern blotting. The optimal effect of phorbol ester was shown at 6 h after treatment with IFN-gamma. Phorbol ester also induced the release of NO to the incubation medium by bacillus Calmette-Guerin-infected peritoneal macrophages. Prolonged incubation of cells with phorbol ester, which down-regulates PKC activity, abolished the synergistic cooperative effect on NO production with IFN-gamma. In addition, such PKC inhibitors as staurosporin or polymyxin B reduced NO production induced by IFN-gamma plus phorbol ester. When the cells were treated with both actinomycin D and phorbol ester after IFN-gamma stimulation, more NO was produced and more iNOS mRNA was expressed than in the cells treated with actinomycin D alone. On the basis of these observations, we conclude that PKC might not be directly involved in the expression of NO synthase, but, instead, might be involved in the stabilization of the iNOS mRNA already expressed by the treatment of IFN-gamma.     

A linear air bearing stage with active magnetic preloads for ultraprecise straight motion

In this paper, we propose a linear motion stage designed with magnetically preloaded air bearings. The magnetic actuators for preloading air bearings were combined with permanent magnets and coils to adjust the air bearing clearance by actively controlling the magnetic force. The system was designed to achieve a simplified configuration of air bearing stage while providing ultraprecise straight motion by actively compensating for the motion errors. The porous aerostatic bearings and magnetic preload actuators were designed and analyzed numerically for a single-axis prototype linear stage driven by a coreless linear motor. A magnetic circuit model was derived for the magnetic actuators. The static stiffness and load capacity of the air bearing stage in the vertical (magnetically preloaded) direction were experimentally measured and compared with the results from the numerical analysis. Motion control laws for three degrees of freedom (i.e., vertical, pitch, and roll motions) were obtained with a high linearity and independence for each axis. The active compensation of three motion errors, the vertical, pitch and roll motion errors were performed through curve-fitting the three errors measured with combination of capacitive gap sensors and a laser interferometer. The errors were reduced from 1.09 to 0.11 μm for the vertical straightness error, from 9.42 to 0.18 arcsec for the pitch motion, and from 2.42 to 0.18 arcsec for the roll motion as level of measured repeatability.     

A study on deburring of magnesium alloy plate by magnetic abrasive polishing

Drilling is one of the most important machining operations in manufacture process. When drilling process is applied, unexpected burrs will be formed on the surface of workpiece. Even a small burr can cause unwanted problems, resulting in low quality products. In order to get better drilled parts, it is very important to know characteristics of burr formation and to remove the burr from the drilled surface with machining process. In this study, magnetic abrasive polishing (MAP) was used to research the deburring factors of magnesium alloy. Moreover, design of experiments was performed to evaluate parameters’ effect on the MAP process. As a result, it was seen that the MAP was useful to remove the burrs on the workpiece without damage from its original surface.