Preparation of porous thin films of a partially aliphatic polyimide

A thermally labile polymer, poly(propylene glycol), was modified to obtain PPG having an amino end group. PPG was incorporated into a partially aliphatic polyimide based on an alicyclic dianhydride, and this afforded triblock copolymers containing various amounts of PPG blocks. The thermal properties of the copolymers were investigated by thermogravimetric analysis and differential scanning calorimetry. The thermal decomposition of the PPG block in the copolymers was carried out at 240°C under various pressures to obtain porous polyimide films. The pores remained during the thermolysis under a reduced pressure of 710 mmHg, whereas they collapsed under (near) atmospheric pressure. The pore size increased as the amount of the PPG block in the copolymers increased. The dielectric constants of the porous polyimides varied from 2.60 to 2.42 with the original copolymer composition. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 532–538, 2006     

Investigation of electrically conductive acrylonitrile‐butadiene rubber

Electrically conductive acrylonitrile‐butadiene rubbers (NBRs) containing carbon black (CB) as conductive filler were prepared in order to investigate their electrical and mechanical properties. The effects of conductive CB loading, temperature, acrylonitrile content, crosslinking density of vulcanizates, and plasticizer on conductivity were studied. The change in electrical conductivity of NBRs with different amounts of CB showed that there is a certain critical point (percolation threshold) where a significant decrease in electrical resistivity (increase in conductivity) is observed. Mechanical properties such as tensile strength, elongation to break, and surface hardness of vulcanized NBRs were measured. It was found that the percolation threshold was 5 phr of CB for the NBR/CB composites. J. VINYL ADDIT. TECHNOL., 13:71–75, 2007. © 2007 Society of Plastics Engineers.     

The Torque Transmission Capabilities of the Adhesively-Bonded Tubular Single Lap Joint and the Double Lap Joint

With the wide application of fiber-reinforced composite materials in aircraft, space structures and robot arms, the design and manufacture of composite joints have become a very important research area because they are often the weakest areas in composite structures.

In this paper, the stress and torque transmission capabilities of the adhesively-bonded tubular single lap joint and the double lap joint were experimentally tested. In order to compare the experimental results with the calculated results, the stress and torque transmission capabilities were analyzed by the 3-dimensional finite element method taking into consideration the nonlinear properties of the adhesive.

From the experiments it was found that the torque transmission capabilities of the adhesively-bonded double lap joint was 2.7 times as large as that of the single lap joint. Also, it was found that the fatigue limit of the double lap joint was 16 times as large as that of the single lap joint.     

Spinning viscose technical yarn into a bicomponent precipitation bath

Conclusions -- The possibility has been demonstrated of preparing viscose yarn by the centrifugal method from a viscose containing additions of urea by spinning into a bicomponent precipitation bath containing sulfuric acid and sodium sulfate.-- Optimum conditions for spinning viscose yarn have been established: a sulfuric acid content of 115 g/l in the precipitation bath, a urea content of 2.5% based on weight of -cellulose in the viscose, and an orientation stretch of 22%.-- Specimens of viscose yarn having a linear density of 13.3 tex have been prepared with a relative breaking load of up to 19 cN/tex, an elongation at break of 17–19%, and a mean squared deviation in dyeing nonuniformity of 0.8–1.0.Translated from Khimicheskie Volokna, No. 4, pp. 33–34, July–August, 1990.     

Oxidation behaviour of titanium-containing brazing filler metals

Brazements on alumina or partially stabilized zirconia (PSZ) of four silver- or copper-based brazing filler metals that contain titanium to promote wetting of and adherence to structural ceramics, were exposed in a thermogravimetric analyser at temperatures up to 700°C to atmospheres of 100% O₂, Ar-20% O₂ and Ar-3 p.p.m. O₂. The alloys included Cu-41.1Ag-3.6Sn-7.2Ti, Ag-44.4Cu-8.4Sn-0.9Ti, Ag-41.6Cu-9.7Sn-5.0Ti and Ag-37.4Cu-10.8In-1,4Ti, at%. All formed external oxides that were more or less protective under all of the test conditions studied. The growth of the oxides followed a parabolic time law. The gains in weight due to oxidation observed were small, ranging (for 45 h exposure at 400 °C to Ar-20% O₂) from 0.20 mgcm⁻² for the Ag-37.4Cu-10.8In-1.4Ti alloy to 0.46 mgcm⁻² for Cu-41.1Ag-3.6Sn-7.2Ti. As expected, weight gain increased with increasing temperature or . Unexpectedly, the titanium played a minor role in the scale formed on any of the filler metals with a titanium oxide, TiO₂, being found on only one alloy — Ag-41.6Cu-9.7Sn-5.0Ti. The brazements on PSZ gained weight at a higher rate than comparative brazements on alumina. We attribute this behaviour to oxygen transport through the zirconia resulting in the growth of an interfacial layer of titanium oxide.     

Fabrication of fine-grain piezoelectric ceramics using reactive calcination

Fine-grain piezoelectric ceramics with the formula Pb(Zr_0.53Ti_0.47)O₃(PZT) were prepared by a reactive calcination process. Using conventional materials and processing techniques, highly reactive powders of PZT were achieved by calcining to or near the point of maximum volume expansion, whereby associated morphological changes resulted in highly reactive powder. Upon milling, powders <0.3 m were readily obtained allowing densification at temperatures <1000°C. The B-site precursor method, whereby the ZrO₂ and TiO₂ oxides were pre-reacted prior to reaction with PbO, further enhanced reactivity by eliminating intermediate reactions and subsequent phase(s) which can hinder densification and overall homogeneity. Highly dense piezoceramics with grain sizes 1 to 2 m exhibiting dielectric and piezoelectric characteristics comparable to conventionally prepared large grain size materials were obtained.     

Robust person re-identification via graph convolution networks

Person re-identification (re-id) aims to identity the same person over multiple cameras; it has been successfully applied to various computer vision applications as a fundamental method. Owing to the development of deep learning, person re-id methods, which typically use triplet networks based on triplet loss, have demonstrated great success. However, the appearances of people are similar and hence difficult to distinguish in many cases. Therefore, we present a novel graph convolution network and enhances traditional triplet loss functions. Our method defines reference, positive, and negative features for triplet loss as three vertices of a graph, respectively, and adjusts their mutual distance through learning. The method adopts graph convolutions efficiently, thereby affording low computational costs. Experimental results demonstrate that our method is superior to the baseline on the Market-1501 dataset. The proposed GCN-based triplet loss considerably contributes to improve re-identification methods quantitatively and qualitatively.

     

In-store shopping with location-based retail apps: perceived value,consumer response,and the moderating effect of flow

Bricks-and-mortar retailers have recently begun to utilize mobile applications delivering location-based services (LBS) as part of their omni-channel strategy to provide consumers with new in-store experiences. In light of this trend, this study examined how consumers’ value perception influences their intention to use LBS in the store and their behavioral responses as well as the moderating effect of flow on the relationships between the perceived benefits/costs and the perceived value of LBS usage. The results indicated that benefits (perceived usefulness and perceived enjoyment) and costs (perceived complexity and perceived privacy risk) were influential antecedents shaping consumers’ value perception of LBS, which in turn impacted their intention to use LBS and behavioral responses (search and purchasing using LBS). Also, we found that the negative relationship between the perceived costs and perceived value was attenuated in high flow states than in low flow states

     

Application of Fuzzy Moving Sliding Surface Approach for Container Cranes

International Journal of Control, Automation and Systems - In this paper, we consider the fuzzy moving sliding surface anti-sway control problem for container cranes. We first introduce the dynamic...     

Irregular Depth Tiles: Automatically Generated Data Used for Network-based Robotic Grasping in 2D Dense Clutter

Recent advances in deep learning have enabled robots to grasp objects even in complex environments. However, a large amount of data is required to train the deep-learning network, which leads to a high cost in acquiring the learning data owing to the use of an actual robot or simulator. This paper presents a new form of grasp data that can be generated automatically to minimize the data-collection cost. The depth image is converted into simplified grasp data called an irregular depth tile that can be used to estimate the optimal grasp pose. Additionally, we propose a new grasping algorithm that employs different methods according to the amount of free space in the bounding box of the target object. This algorithm exhibited a significantly higher success rate than the existing grasping methods in grasping experiments in complex environments.