Flash Spark Plasma Sintering (FSPS) of Pure ZrB2

Pure ZrB₂ powder was Flash sintered in an SPS furnace (FSPS). The samples were densified up to 95.0% in 35 s under an applied pressure of 16 MPa. Compared to Conventional SPS (CSPS), the newly developed FSPS technique resulted in an unprecedented energy and time savings of about 95% and 98% respectively. ZrB₂ monoliths obtained by CSPS and FSPS were compared with respect to microstructures, densification behavior, and grain growth. The developed methodology might find application to a wide range of highly conductive ceramics as such refractory borides and carbides.     

Universal Control on Pyroresistive Behavior of Flexible Self‐Regulating Heating Devices

Smart heating devices with reliable self‐regulating performances and high efficiency, combined with additional properties like mechanical flexibility, are of particular interest in healthcare, soft robotics, and smart buildings. Unfortunately, the development of smart heaters necessitates managing normally conflicting requirements such as good self‐regulating capabilities and efficient Joule heating performances. Here, a simple and universal materials design strategy based on a series connection of different conductive polymer composites (CPC) is shown to provide unique control over the pyroresistive properties. Hooke's and Kirchhoff's laws of electrical circuits can simply predict the overall pyroresistive behavior of devices connected in series and/or parallel configurations, hence providing design guidelines. An efficient and mechanically flexible Joule heating device is hence designed and created. The heater is characterized by a zero temperature coefficient of resistance below the self‐regulating temperature, immediately followed by a large and sharp positive temperature coefficient (PTC) behavior with a PTC intensity of around 10⁶. Flexibility and toughness is provided by the selected elastomeric thermoplastic polyurethane (TPU) matrix as well as the device design. The universality of the approach is demonstrated by using different polymer matrices and conductive fillers for which repeatable results are consistently obtained.     

Influence of Asymmetric Cyclic Loading on Structural Evolution and Deformation Behavior of Cu-5 at.% Zr Alloy: An Atomistic Simulation-Based Study

Molecular dynamics (MD) simulation-based studies of tensile test and structural evolution of Cu-5 at.% Zr alloy under asymmetric cyclic loading (i.e., ratcheting behavior) considering various stress ratios such as ? 0.2, ? 0.4 and ? 0.6 for different temperatures, viz.≈ 100, 300 and 500 K have been performed using embedded atom model Finnis–Sinclair potential. According to obtained stress–strain response from MD calculation, Cu-5 at.% Zr alloy specimen is pristine in nature as sudden drop in stress just after yield stress and subsequent elastic type deformation are observed for this alloy. Predicted ratcheting strain by MD simulation for Cu-5 at.% Zr alloy varies from 4.5 to 5%. Significant increase in ratcheting strain has been observed with the increase in temperature. Slight reduction in crystallinity is identified at the middle of the each loading cycle from the performed radial distribution function analysis and cluster analysis.     

Dragonfly-based swarm system model for node identification in ultra-reliable low-latency communication

Neural Computing and Applications - Latency and reliability are essential parameters for enabling ultra-reliable low-latency communication (URLLC). Therefore, an approach for node identification...     

A high payload reversible data hiding algorithm for homomorphic encrypted absolute moment block truncation coding compressed images

Multimedia Tools and Applications - With the aim to ensure privacy and security of secret message, an enhanced reversible data hiding algorithm in encrypted as well as compressed domain is proposed...     

Analysis of Frequent Failure of Oil Well Tubings Due to Formation of Longitudinal Slit

In an onshore oil field, many premature tubing failures were observed in wells operating on sucker rod pump. Failures were in the form of longitudinal crack/vertical slit. During last three to four years, the failure frequency had increased and in one well, new tubing vertically cracked in 8 months only. In the internal surface of the tubing, a longitudinal grooving was observed. The shape of the groove resembled the sucker rod and the crack was along the groove. Observation of grooved region under SEM revealed abrasion features typical of mechanical wear. Small corrosion pits were also observed on some portion of grooved region. As the well was vertical, so chance of contact between tubing and sucker rod was low. But tubing was freely suspended in the well, i.e., there was no tubing anchor which made it vulnerable for the buckling. Analytical studies showed that the failed tubing was in buckling region. On comparison of hardness, it was observed that tubing material was softer than the sucker rod. Buckling of the tubing resulted in rubbing of sucker rod against tubing wall due to which tubing had worn out in the form of groove. Wear-oxidation and oxidation-wear of tubing surface at grooved region and corrosive agents of produced water accelerated this material removal process and when the wall thickness of the tubing at groove region reduced to a point where it was not enough to withstand the hoop stresses, a longitudinal crack formed in the grooved region and tubing failed.     

On some measures for grouping efficiency

One of the traditional methods on managing risk is taken using engineering decisions taken during the project development. In this paper, we propose a new method for risk assessment of a tunnel project where there are three main parameters called taskmaster, adviser, and contractor. The proposed model of this paper is built based on interactive framework of a game theory where, in making decision, each player considers other possible risks choices. We implement three-person cooperative game theory combined with an interactive decision structural model of fuzzy analytical hierarchy process to perform a balance between actions and suitable cooperative strategy for each player. The results reveal that collaboration strategies give the highest outcome for the three players. It also recommends owner managers, design managers, and contractor managers to make collaboration in undertaking innovation while the operator managers need to let an independent organization clearly identify the appropriate risk mitigation measures to be implemented in a timely manner.     

视频转码技术与系统要求相匹配可显著提升新一代视频应用性能

音视频转码曾被视为一种直接的、传统的处理过程,可将源视频编码,生成略差于原始未压缩内容的版本,然后将其重新解码为传输或观看所要求的格式。     

Influence of silica and electron beam radiation on the properties of a high vinyl styrene-butadiene-styrene block copolymer

Radiation crosslinking of polymers has gained importance over conventional crosslinking because the system is fast, pollution free and relatively simple. In high energy electron beam curing, which is one of the radiation curing methods, the material to be cured is bombarded with electrons of specified energy to produce free radials. These radicals unite to give rise to chemical crosslinks. In the process, some unwanted chain scission may also occur. The mechanical properties of such electron beam crosslinked systems can further be improved by the incorporation of nanosilica. In this work, a high vinyl (~50%) S-B-S block copolymer incorporated with varying doses of specific hydrophilic nanosilica was irradiated with electron beam at 25 and 50 kGy. Mechanical properties were studied and compared with that of the unirradiated system. The influence of a silane coupling agent was also investigated. Morphological studies were done to understand the dispersion of nanosilica in the polymer matrix. Relatively moderate amounts of nanosilica along with an optimum dose of the coupling agent were found to be effective in improving the properties. Rheological properties were also studied in details to understand the possibility of recycling the polymer.