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Abrasive Water Jet Machining (AWJM) is an advanced machining process that has a variety of applications, including machining of hard-to-machine materials, drilling, milling, coating removal, polishing, etc. They are attractive because of their versatility, absence of heat-affected zones, low thermal-distortions, low cutting-forces, and environment-friendly nature. However, use of plain-water in AWJM poses some problems due to lack of jet coherence, poor suspension characteristics, and unsatisfactory performances in submerged-cutting and cutting of hollow surfaces. Countering these problems appropriately can lead to better cutting performances in terms of material removal rate, depth of cut, kerf-width, and kerf-taper. It can be achieved with addition of some additives in abrasive water-jet. These additives are mostly polymers of high molecular mass, which increases viscosity, suspension capability, and stability of jet, while reducing drag. In addition to AWJM, the effect of polymeric-additives in other water-based jets like Abrasive-Slurry-Jet (ASJ), High-pressure ASJ, etc. are also discussed. Therefore, this study aims to identify and list of different additives that are used in AWJM and other water-jet-based machining-processes over a past few decades, and to provide a run-through on their performances. It can provide the significant information to researchers working in fields related to waterjets.

Body Area Sensor Network (BASN) communication methods meet clients' multi-level requirements through Wearable Internet of Things (WIoT) systems. Transparency at management levels, heterogeneous support, and distributed communication to users are requirements of the PCS. Providing essential functions is a serious problem. A flexible Ubiquitous Computing (UC) architecture presented in this study is used to improve the reliability of end-user communication in the WIoT-based health sensor approach. According to this method, demand and sharing variables provide the foundation for the evaluation of resource allocation through recurrent learning. A proposed method could be used to implement end-user mobility management on WIoT healthcare sensors for data transmission, resource allocation and sharing. To show the integrity of the approach, some parameters were used in the actual evaluation and performance predictions. In the ubiquitous ecosystem, the uninterrupted flow was guaranteed to reduce the likelihood of a request being blocked. Memory control to density assignment at the framework level through storage management helps reduce backlogs and failures when allocating resources. The proposed approach enhances storage utilization, bandwidth, and request management besides lowering connection speed, backlogs, and request failure compared to the existing systems.

Aluminium alloy, AlSi10Mg is being used widely because of its light weight and good mechanical properties. The material has good strength, hardness, high corrosion resistance, and good thermal and electrical conductivity. The AlSi10Mg samples were fabricated using the powder bed fusion (PBF) method. The PBF is a widely used additive manufacturing (AM) method that uses powder bed fusion technology to build up near-net shape parts. As-built sample surfaces were characterised in terms of 3D surface roughness parameters. Since fatigue and wear can occur readily during the life cycle of any component, it is important to study the tribological aspects of AlSi10Mg produced by the PBF method. Dry sliding tests were performed using as-built AlSi10Mg samples as stationary blocks against a 6 mm diameter Alumina ball as the counter face. Tests were performed using different loads and velocities ranging from 10–45 N and 1–4 mm/s respectively. Although complex geometries can be fabricated using the PBF method, the surface quality is insufficient for different applications. After chemical polishing of the samples, tribology experiments were repeated, highlighting the substantial impact of surface finishing on both surface properties and tribological behaviour. Furthermore, the tribological behaviour of AMed metal parts is notably influenced by load and velocity parameters. Wear tests underscore that loads and velocities significantly influence the wear behaviour of the component, with contact pressure potentially leading to microstructural modifications due to thermal softening induced by the sliding process.

Micro-electrical discharge machining (micro-EDM) is a widely used technique for producing complex geometries with high precision in metals, including nitinol (NiTi) alloys. This review provides insights into the process parameters, electrode material, and surface integrity for the micro-EDM of NiTi. The pulse duration, pulse frequency, and discharge current are critical parameters that affect the machining performance of NiTi. Copper-tungsten and tungsten carbide are commonly used electrode materials for micro-EDM of NiTi. The surface integrity of the machined surface is an essential consideration for biomedical applications. There is a pressing need for the investigation of the microstructure and phase transformation of NiTi after micro-EDM to understand the influence of machining on the material properties. This review provides valuable information for researchers and engineers to optimize the machining performance and improve the material properties of NiTi for biomedical applications.

This report describes the photo chromic activity of nano silver chloride particles impregnated polyvinyl alcohol thin film fabricated by solvent casting method. The nano size silver chloride particles have been prepared by wet chemical route in the presence of polyvinyl pyrrolidone as a capping agent. Evaluation of the structural features of silver chloride and their polymer composites was performed by employing FTIR, SEM, AFM, UV-Vis. analysis and XRD data. AFM analysis reveals the size of silver chloride particles in the range of 80 nm. From the SEM image, the morphology of the nano particles used in this study has been explored. The XRD pattern of the prepared AgCl nano particles exhibits characteristic peaks in the X-ray diffraction corresponding to FCC geometry. The photochromic ability of the polymer matrix towards visible light has been examined through UV- visible spectrophotometer. The opaque state of the materials is observed when the polymer matrix was exposed to sunlight and turns transparent on keeping the substrate in the dark. The percentage of transmittance of the film during the exposure to sunlight and in the dark was measured and reported.

Intima-media thickness (IMT) is a well-known indicator of the physical properties of carotid artery in vascular disease examinations. In the present study, two different image segmentation techniques, based on edge detection and dynamic programming algorithms, were examined to extract the boundary of intima-media thickness. The results of these two methods were compared using back propagation algorithm. The features like area, shape, intensity, size of internal diameter and length of segmented regions traced by edge detection algorithm were compared with the same parameters traced by the dynamic programming algorithm. In conclusion, both these methodologies provide a reliable tool to detect the intima-media thickness in ultrasound images and can be used efficiently as secondary observer in clinical decision making.

Increasing complexity and manufacturing costs, along with the fundamental limits of planar CMOS devices, threaten to slow down the historical pace of progress in the semiconductor industry. We have proposed and demonstrated proof-of-concept of a simple and low-cost way to fabricate dual-damascene copper (Cu) on-chip interconnect or Back-End-Of-the- Line (BEOL) structures using a novel multifunctional on-chip electrical insulator called a photo-patternable low dielectric constant (low-) dielectric (PPLK) material [Q. Lin, et al, Proc. SPIE,2010]. This demonstration was accomplished with a silsesquioxane-based (SiCOH), =2.7 material which is compatible with 248 nm optical lithography. In this paper, we report on the extension of the photo-patternable low- concept to the ultra-low- (<2.5) regime and resolution down well below 100 nm with 193 nm lithography as well as e-beam lithography. We have accomplished this demonstration using the same silsesquioxane-based (SiCOH) material platform as that of the 248 nm photo-patternable low- materials. The 193 nm photo-patternable low- materials possess dielectric constants below 2.5 and are able to resolve 100 nm half-pith line/space features with dry 193 nm single exposure lithography. The resolution of photopatternable low- materials can be pushed down to 40 nm half-pith line and space features with a line-edge-roughness less than 3.0 nm with e-beam lithography.

Abstract: The interfacial reactions at the solder joints of interest in microelectronic structures have been extensively investigated in order to control the soldering process and thereby to provide strong and reliable solder joints. These reactions comprise the dissolution of a base metal into a molten solder, the concomitant growth of intermetallics in the liquid state, and the growth of intermetallics in the solid state. Various experimental techniques employed include conventional cross-sectional metallography, scanning electron microscopy, electron microprobe analysis, x-ray diffraction and others. In this study, the interfacial reaction between tin and copper has been investigated by using differential scanning calorimetry which provides a simple means to study such reactions and complements information obtained from other techniques. The experimental results have been applied to understand the interfacial reactions in two important examples: one for a soldering process with copper metallization, and another for a high conductivity, Pb-free, electrically conducting adhesive which contains tin-coated copper powder as conducting filler particles.

Abstract: Electrically and/or thermally conducting adhesive materials are classified into two categories depending on their conduction modes: isotropic and anisotropic materials. Silver-particle filled epoxy is the most common example of the class of isotropic materials which are conductive in all directions. This material has been long used in the electronic applications as a die-bonding material, where its good thermal conduction rather than its electrical conduction property is utilized. The silver-filled epoxy material has several limitations for high performance electrical interconnections, such as low electrical conductivity, increase in contact resistance during thermal exposure, low joint strength, corrosion issue due to silver migration, difficulty in rework, and so forth. The anisotropic conducting material provides electrical and/or thermal conduction only in one direction. An anisotropic conducting film (ACF) is used for interconnecting TAB mounted chips to a liquid crystal display panel, where fine pitch interconnection and low temperature assembly are required. In this paper, a brief review of the state-of-art conducting adhesive technology is provided. Subsequently, development of new conducting adhesive materials is presented for several different applications, which include high temperature materials for ceramic substrates, and low temperature materials for organic substrates.

Abstract: The use of lead (Pb)-containing solders for the interconnections of microelectronic subsystem assembly and packaging has become an environmental issue. Extensive research and development activities for replacing Pb-containing solders with environmentally safe Pb-free solders are in progress in electronic industries, universities, and national laboratories. One key technical issue recognized with the Pb-free, Sn-rich solders is a need to develop a good barrier metallurgy to control the interfacial reactions, namely, dissolution of the base metal(s) and concurrent formation of intermetallics at the soldering interfaces. In this study, the interfacial reactions of Cu and Ni metallizaton with several Pb-free and Pb-containing solders are investigated. The dissolution kinetics of the base metal(s) as well as the growth kinetics of the intermetallics are discussed.

We present in this paper an approach for mechanically certifying the correctness of systolic algorithms and detail the correctness proof of a systolic algorithm for a dynamic programming (optimal parenthesization) problem.

A systematic matrix of fatigue crack growth rate data in a hydrogen environment has been generated in a nickel-copper alloy and compared with the base line data in the milder oxygen and vacuum environments described in the preceding paper. It is found that crack growth in the hydrogen environment is characterized by high values of the Paris equation exponent and faster crack propagation rates as compared to those in the milder environments. Fractographic examination shows that brittle inter granular separation occurs superimposed on an otherwise ductile crack mode in the hydrogen tests. Quantitative fractographic analysis of the hydrogen affected fracture surfaces indicates that the percentage of intergranular failure (area fraction) is a uniquely related function of the mean stress intensity rather than the maximum stress intensity level of fatigue loading. This dependence is discussed in terms of dislocation sweep-in transport of hydrogen deep into the plastic zone during fatigue cycling.

Fatigue crack growth rates have been determined in a nickel-copper alloy in the mild test environments of vacuum and oxygen. It is found that the fatigue crack growth mode in both vacuum and oxygen is ductile and the growth rate is sensibly independent of the maximum stress intensity levels and stress intensity ratio. The growth rate is found to be lower in vacuum than in oxygen, and the growth rate dependency on the cyclic stress intensity range is more pronounced in vacuum than in oxygen. These differences in behavior may be consistent with differences in crack closure behavior for the two environments.

Thereachability, deadlok detection andunboundedness detection problems are considered for the class ofcyclic one-type message networks of communicating finite state machines. We show that all the three problems are effectively solvable by (a) constructing canonical execution event sequences which belong to a context-free language, and (b) showing that the reachability sets are semilinear. Our algorithms have polynomial complexity in terms of size of a global structure of a network, called theshuffle-product. The relationships between general Petri nets and the class of communicating finite state machines considered here are also explored.

All synthesized compounds exhibit good antimicrobial properties against most of the tested microorganisms.