Suction-based Grasp Point Estimation in Cluttered Environment for Robotic Manipulator Using Deep Learning-based Affordance Map

Machine Intelligence Research - Perception and manipulation tasks for robotic manipulators involving highly-cluttered objects have become increasingly in-demand for achieving a more efficient...     

Fuzzy geographically weighted clustering using artificial bee colony: An efficient geo-demographic analysis algorithm and applications to the analysis of crime behavior in population

Geo-demographic analysis is an essential part of a geographical information system (GIS) for predicting people’s behavior based on statistical models and their residential location. Fuzzy Geographically Weighted Clustering (FGWC) serves as one of the most efficient algorithms in geo-demographic analysis. Despite being an effective algorithm, FGWC is sensitive to initialize when the random selection of cluster centers makes the iterative process falling into the local optimal solution easily. Artificial Bee Colony (ABC), one of the most popular meta-heuristic algorithms, can be regarded as the tool to achieve global optimization solutions. This research aims to propose a novel geo-demographic analysis algorithm that integrates FGWC to the optimization scheme of ABC for improving geo-demographic clustering accuracy. Experimental results on various datasets show that the clustering quality of the proposed algorithm called FGWC-ABC is better than those of other relevant methods. The proposed algorithm is also applied to a decision-making application for analyzing crime behavior problem in the population using the US communities and crime dataset. It provides fuzzy rules to determine the violent crime rate in terms of linguistic labels from socioeconomic variables. These results are significant to make predictions of further US violent crime rate and to facilitate appropriate decisions on prevention such the situations in the future.     

Synthesis of magnetite nanoparticles by surfactant-free electrochemical method in an aqueous system

A simple surfactant-free electrochemical method is proposed for the preparation of magnetite nanoparticles using iron as the anode and plain water as the electrolyte. This study observed the effects of certain parameters on the formation of magnetite nanoparticles and their mechanism in the system, including the role of OH^? ions, the distance between electrodes and current density. We found that OH^? ions play an important role in the formation of magnetite nanoparticles. Particle size can be controlled by adjusting the current density and the distance between electrodes. Particle size increases by increasing the current density and by decreasing the distance between electrodes. Particle formation cannot be favored when the distance between electrodes is larger than a critical value. The magnetite nanoparticles produced by this method are nearly spherical with a mean size ranging from 10 to 30 nm depending on the experimental conditions. They exhibit ferromagnetic properties with a coercivity ranging from 140 to 295 Oe and a saturation magnetization ranging from 60 to 70 emu g^?1, which is lower than that of the corresponding bulk Fe₃O₄ (92 emu g^?1). This simple method appears to be promising as a synthetic route to producing magnetite nanoparticles.     

The influence of calcination temperature on catalytic activities in a Co based catalyst for CO2 dry reforming

The carbon dioxide dry reforming of methane (CDR) reaction could be thermodynamically favored in the range of 800 to 1,000 °C. However, the catalyst in this reaction should be avoided at the calcination temperature over 800 °C since strong metal support interaction (SMSI) in this temperature range can decrease activity due to loss of active sites. Therefore, we focused on optimizing the temperature of pretreatment and a comparison of surface characterization results for CDR. Results related to metal sintering over support, re-dispersion by changing of particle size of metal-support, and strong metal support interaction were observed and confirmed in this work. In our conclusion, optimum calcination temperature for a preparation of catalyst was proposed that 400 °C showed a higher and more stable catalytic activity without changing of support characteristics.     

The nature of polymer grafts and substrate shape on the surface degradation of poly(l‐lactide)

Surface grafting of functional polymers is an effective method to alter material properties and degradation behavior. Two different substrate shapes of poly(l ‐lactide) (PLLA), i.e., films and microparticles, were surface‐grafted with hydrophilic monomers, and their surface degradation was monitored. Surface grafting with a hydrophilic and acidic polymer graft [acrylic acid (AA)] induced large alterations in the surface morphology and topography of the films. In contrast, hydrophilic and neutral polymer grafts [acrylamide (AAm)] had no significant effect on the surface degradation behavior, while the PLLA reference and co‐monomeric (AA/AAm) polymer‐grafted samples exhibited intermediate surface degradation rates. The grafted PAA chains induced a local acidic environment on the surface of the substrates, which in turn catalyzed the surface degradation process. This effect was more pronounced in the films than in the microparticles. Thus, the nature of the grafted chains and substrate geometry were shown to affect the surface degradation behavior of PLLA substrates. © 2015 The Authors Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42736.     

Evaluation of Effective Width and Distribution Factors for GFRP Bridge Decks Supported on Steel Girders

Glass fiber-reinforced polymer (GFRP) bridge deck systems offer an attractive alternative to concrete decks, particularly for bridge rehabilitation projects. Current design practice treats GFRP deck systems in a manner similar to concrete decks, but the results of this study indicate that this approach may lead to nonconservative bridge girder designs. Results from a number of in situ load tests of three steel girder bridges having the same GFRP deck system are used to determine the degree of composite action that may be developed and the transverse distribution of wheel loads that may be assumed for such structures. Results from this work indicate that appropriately conservative design values may be found by assuming no composite action between a GFRP deck and steel girder and using the lever rule to determine transverse load distribution. Additionally, when used to replace an existing concrete deck, the lighter GFRP deck will likely result in lower total stresses in the supporting girders, although, due to the decreased effective width and increased distribution factors, the live-load-induced stress range is likely to be increased. Thus, existing fatigue-prone details may become a concern and require additional attention in design.     

Incorporation of Dust Particles into a Growing Film During Silicon Dioxide Deposition from a TEOS/O2 Plasma

The effects of gas flow rate on particle formation and film deposition during the preparation of silica thin film using a TEOS/O₂ plasma were investigated. Particle formation and growth are suppressed with increasing gas flow rates. The film deposition rate increases with increasing gas flow rate, reaches a maximum value, and eventually decreases again. However, the uniformity of the film tends to degrade at high gas flow rates. At a high gas flow rate, some particles trapped in the sheath near the grounded electrode pass through the sheath to reach the substrate and are then embedded in the growing film. A self-consistent sheath model combined with particle force balance based on charge fluctuation was developed to explain these experimental findings qualitatively. The model reveals that charge fluctuation is a key factor for the particle to overcome the potential barrier of the negatively charged particles to pass through the sheath, eventually reaching the substrate. The model further shows that the probability of a particle being deposited on the substrate is higher for increased gas flow rates, which correctly predicts the experimentally observed trend.     

Gas–Surface Interactions on Quasicrystals

To commemorate the awarding of the Nobel Prize for Chemistry to Daniel Shechtman for his discovery of quasicrystals, this paper reviews our recent studies of the interaction of rare gases and hydrocarbon gases with the tenfold surface of quasicrystalline decagonal Al-Co-Ni.     

Cooling Process and Cast Structure of Zr-Al-Ni-Cu–Based Bulk Metallic Glasses Produced in Various Atmospheres

Cooling process in the production of Zr₆₅Al_7.5Ni₁₀Cu_17.5-based bulk metallic glasses (BMGs) was investigated in various chamber atmospheres in Cu mold casting. Two different cooling modes, consisting of the direct heat transfer between the melt and Cu mold in the high temperature and indirect transfer via cavity in the low-temperature regions, are suggested. In the later case, the cooling effect should depend on the chamber atmosphere, which results in the formation of glassy structure with large relaxation enthalpy casting under the ambient Ar and He atmospheres due to a good thermal conductivity. The less relaxed BMGs produced by an improved cooling effect are also expected to contain a large amount of free volume for significant deformability. Actually, it is clarified that the compressive plastic deformation is improved with an increase of the relaxation enthalpy. The present study indicates a necessity of development of the glassy structure, i.e., relaxation state, and provides a new technique of the formation of less relaxed glassy structure for the improvement of plasticity in BMGs.