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Electroless plating has been considered as an effective approach to provide protection and enhancement for metallic materials with many excellent properties in engineering field. This paper begins with a brief introduction of the fundamental aspects underlying the technological principles and conventional process of electroless nickel–phosphorus (Ni–P) coatings. Then this paper discusses different electroless nickel plating, including binary plating, ternary composite plating and nickel plating with nanoparticles and rare earth, with the intention of improving the surface performance on steel substrate in recent years in detail. Based on different coating process, the varied features depending on the processing parameters are highlighted. Separately, diverse preparation techniques aiming at improvement of plating efficiency are summarized. Moreover, in view of the outstanding performance, such as corrosion resistance, abrasive resistance and fatigue resistance, this paper critically reviews the behaviors and features of various electroless coatings under different conditions.

In order to improve the tribological performance of AISI 316 stainless steel (316 SS) under grease lubrication, electrochemical processing was conducted on it to obtain a rough (surface texturing-like) surface by making use of the high sensitivity of austenitic stainless steel to pitting corrosion in Cl^--rich environment. Numerous corrosion pits or micro-ditches acted as micro-reservoirs on the obtained surface. While the grease could offer consistent lubrication, and then improve the tribological performance of 316 SS. Tribological behaviors of raw 316 SS and the treated sample were measured using a reciprocating type tribometer sliding against GCr15 steel counterpart under dry and grease lubrication conditions. The results showed that the mass losses of the two samples were in the same order of magnitude, and the raw sample exhibited lower friction coefficient in dry sliding. When the tests were conducted under grease lubrication condition, the friction coefficients and mass losses of the treated sample were far lower than those of the raw 316 SS. The tribological performance of 316 SS under grease lubrication was drastically improved after electrochemical processing.

Micro-arc oxidation coatings were fabricated on 7E04 aluminum alloy substrates by micro-arc oxidation (MAO) in the electrolytes with the graphite addition varying from 0 to 8g/L (0, 2, 4, 6, 8g/L). The effect of graphite concentration on the surface morphologies, micro-hardness, thickness, phase composition and corrosion resistance of coatings was investigated. With the graphite powder concentration increasing, the oxidation voltage decreased gradually and the thickness of coatings firstly dropped down and then went up. It is found that the size of micro-pores and sintered discs declined with increase of graphite concentration. The XRD results indicated that MAO coatings mainly consisted of $\gamma$-Al₂O₃, $\theta$-Al₂O₃, SiO₂ and a little $\alpha$-Al₂O₃. The corrosion resistance of coatings was improved with the addition of graphite powder. The study reveals that the appropriate graphite powder in the electrolytes is essential to promote the performance of the coatings.

With the continuously rapid development of materials science, better properties are equably required in the area of material surface engineering, especially the surface friction and high-temperature oxidation resistance of titanium alloy. It is a great approach to select a scientific way for surface treatment to improve the surface performance so as to obtain surface films/coatings/layers. It can provide a vital latent remedy to the insufficient high-temperature oxidation resistance and wear resistance of titanium alloys. Pack cementation is a reliable means at present by virtue of its distinct composition, covering pollution-free and the firm metallurgical bonding between the alloying coating and the matrix. In the last few years, with the growing demands for the surface performance of materials in multifarious harsh environments, the coating obtained by pack cementation is developing toward controlling coating composition accurately and applying it to complex parts. This review opens with an abbreviated introduction of pack cementation technology. The recent developments of pack cementation technology for enhancing diverse surface properties are scientifically reviewed in the aspects of background, previous research results and the future development directions.

Due to the unique properties of titanium (Ti) and its alloys, it has a particularly wide range of applications in aerospace, automotive, medical and other fields. However, the problems of low surface hardness, high friction coefficient and low wear resistance of Ti alloys limit its development to a certain extent. The destruction of Ti and its alloys often occurs on the surface of materials such as wear damage, corrosion, and oxidation resistance. Therefore, the exploration and application of surface strengthening technology is particularly important. The cathodic plasma electrolytic deposition (CPED) technology, as a surface modification technology, can achieve better adhesion and facilitate the material to achieve better comprehensive performance. This paper briefly introduces the basic concepts, principles and development progress of CPED. Starting from the preparation of ceramic coatings, metal coatings, diamond-like carbon films and composite coatings, it summarizes the application of CPED in Ti and its alloys. Applications in alloys to improve thermal oxidation resistance, wear resistance, corrosion resistance, and film-based adhesion. At the end, its development in the new era environment is prospected.

With the rapid advancement of modern society, the applications of materials are expanding across various fields. Among these, metallic materials have found wide use in industries such as biomedical, petrochemical, aerospace, orbital bridges, and marine vessels, making significant contributions to the manufacturing sector of the economy. As heavy machinery in industries undergoes rapid updates and iterations, there is a growing demand for metal fittings and structural components. However, these metal materials often experience common forms of failures, such as corrosion and wear, particularly at the surface, highlighting the crucial importance of surface protection. Material surface engineering presents a viable solution that effectively balances internal performance and investment costs, specifically addressing issues related to surface degradation and repair. By controlling the surface composition and structural design, it becomes possible to manage friction, corrosion, and mechanical properties of metal materials, resulting in notable advancements. One notable technique that has gained considerable traction in automotive engineering, aerospace, and other industries is tungsten inert gas (TIG) cladding. This technique offers unique composition properties, a pollution-free coating process, and a strong metallurgical bond between the alloy coating and the substrate. This review aims to provide a concise overview of TIG cladding, discussing parameter selection and the impact of different cladding powders on coating characteristics. Additionally, it summarizes the recent applications and research status of TIG cladding on titanium alloys, stainless steels, and other nonferrous alloys concerning their wear resistance, mechanical properties, and corrosion resistance. By exploring the advancements and findings in these areas, this review aims to contribute to the body of knowledge in the field of surface engineering and facilitate further research and development in TIG cladding technology.

Spatial data, ranging from various land information data to different types of environmental data, are typically collected and used by different custodians. The full benefits of using spatial data can be achieved by combining the data from different sources covering a common region. Due to organizational, political and technical reasons, it is unrealistic to physically integrate the vast amount of spatial data managed by different systems in different organizations. A practical approach is to provide interoperability to support multi-site data queries. In this paper, we study the performance aspect of complex spatial query processing. We propose a framework for processing queries with multiple spatial and aspatial predicates using data from multiple sites. Using a new concept called generalized filter, a query is processed in three steps. First, an aspatial filter that incorporates some conditions derived from spatial predicates is used to find a set of candidates, which is a superset of the final query results. Then, the candidates are manipulated and a refinement step is executed following an optimized candidate sequence. Finally, a post-processing step is used to handle spatial expressions in query results. The focus of this paper is to generate enhanced filters in order to minimize the need of transferring and processing complex spatial data.

With the increasing number of Web Services with similar or identical functionality, the non-functional properties of a Web Service will become more and more important. Hence, a choice needs to be made to determine which services are to participate in a given composite service. In general, multi-QoS constrained Web Services composition, with or without optimization, is a NP-complete problem on computational complexity that cannot be exactly solved in polynomial time. A lot of heuristics and approximation algorithms with polynomial- and pseudo-polynomial-time complexities have been designed to deal with this problem. However, these approaches suffer from excessive computational complexities that cannot be used for service composition in runtime. In this paper, we propose a efficient approach for multi-QoS constrained Web Services selection. Firstly, a user preference model was proposed to collect the user's preference. And then, a correlation model of candidate services are established in order to reduce the search space. Based on these two model, a heuristic algorithm is then proposed to find a feasible solution for multi-QoS constrained Web Services selection with high performance and high precision. The experimental results show that the proposed approach can achieve the expecting goal.

This paper tests the relationship between takeovers and poor management performance, known as the market discipline hypothesis. We create a proprietary new Australian dataset for this study by individually researching company reports for executive retention data. We assess takeover targets for pre-bid managerial inefficiency and find evidence that Australian target companies exhibit negative abnormal returns prior to takeover. In particular, we find that disciplinary targets underperform their non-disciplinary counterparts. Our tests take into account the difference between friendly and hostile takeovers, and the industry sector in which the target firm operates.

Research suggests that the cash ratios of private firms are lower than the ones of public firms, which is not consistent with an expectation for increased importance of the precautionary motive for firms with fewer funding options. The study provides a significant explanation on these lower ratios, attributed to differences in leverage, capital expenditures, internally generated cash flows, and corporate governance. The study finally testifies that excess cash holdings are positively associated with future operating performance for private, but not public firms, a finding which is interpreted as a manifestation of capital raising constraints for unlisted versus listed firms.

In this paper, we propose a quantitative approach to measure the extent of corporate culture disclosure. Using this new measure, we document that corporate culture disclosure and performance is positively correlated in terms of stock return, return on assets, cash flow, earnings growth, sales growth, return on sales, and turnover; corporate culture disclosure also helps to lower the negative impact of missing earnings benchmarks using a sample of Chinese firms. In addition, we find that the extent of corporate culture disclosure is negatively correlated with earnings management and operational risk exposure. Essentially, our comprehensive analysis provides a good illustration of using the method to measure corporate culture disclosure.

This work aims to inspect the common debate about the implication of derivative instruments in amplifying the last financial crisis. To reach this goal, the study chooses a sample of banks entirely from emerging countries — over the whole period 2003–2011 — in which we examine the impact of derivatives simultaneously on performance, risk and stability during the ordinary period “the pre-crisis period”, 2003–2006, and the unstable period “the crisis and post crisis period”, 2007–2011. The regressions are estimated by generalized methods of moments (GMM) as developed by Blundell and Bond (1998). The major conclusion reveals that only swaps can be considered as implicated in the intensification of the last financial crisis. Therefore, the rest of derivatives instruments cannot be responsible in the amplification of the recent financial crisis. Indeed, the widespread idea accusing all derivatives to be in part responsible of the intensification of the last financial crisis should be revised.

IEEE802.11 WLANs show increasing growth in popularity. Since these networks operate in the unlicensed ISM bands where the number of non-overlapping channels is limited, the growing number of wireless nodes leads to interference. It is well known that the interference leads to degraded performance of WLANs, especially in densely populated areas where the number of overlapping nodes is very large. Channel assignment algorithms have been proposed in recent years, in order to minimize or avoid interference between neighboring access points and hence alleviating the problem. In particular, weighted assignment algorithms have been frequently occurring in the literature. However, the effects of these algorithms are currently not well understood. In this paper, we present results, which show that weighted channel assignment algorithms that do not consider traffic categories can lead to heavy interference among WLANs with delay sensitive traffic, e.g. voice traffic. In order to overcome this, we instead propose a weighted access category channel assignment algorithm (WACCA). We present results from experiments, which show that WACCA achieves a small degree of Interference (DOI) as compared with a greedy algorithm. We also show that there is a tradeoff with convergence time. Furthermore, we propose an integration of WACCA with dynamic transmission power control and show how this combined method produces even more gain.

The objective of this research is to study the process of examining documents by computing comparisons between the representation of the information need (the queries) and the representations of the documents. Also, we will automate the process of representing information needs as user profiles by computing the comparison between the user profile and the representations of the documents.

We consider an automated process to be successful when it produces results similar to those produced by human comparison of the documents themselves with actual information need. Thus, we will compare ad-hoc retrieval and filtering retrieval tasks and examine the differences between them in terms of the information retrieval process.

We have selected 242 Arabic abstracts that were used by Hmeidi [7]. All these abstracts involve computer science and information systems. We have also designed and built a system to compare two different retrieval tasks: ad-hoc retrieval and filtering retrieval. Here, we define ad-hoc and filtering retrieval systems and illustrate the development strategy for each one. We compare the two tasks on the basis of recall/precision evaluation, system usability, domain search, ranking, construction complexity, and methodology. From this experiment, we conclude that ad-hoc retrieval gives better performance than filtering retrieval. We also consider the advantages of using filtering services in the information retrieval process.

Compactness is a valuable property in designs of assistive devices and exoskeletons. Current devices are large and stigmatizing in the eyes of the users. The cosmetic appearance will increase by reducing the size. The users want a device that is small enough to be worn underneath the clothes, so it becomes unnoticeable. The goals of this paper are (1) to provide an overview of the shape-changing-material-actuated large-deflection compliant rotational joints, (2) provide new introduced performance indicators that evaluate the designs on performance with respect to volume or weight and (3) design a compact active assistive elbow device as a case study. In order to reach these goals, two evolving fields of study are brought together that have great potential to reduce the size of exoskeletons: smart materials and compliant rotational joints. Smart materials have the ability to change their shape, which make them suitable as actuators. Compliant joints can be compact, since they are made out of one piece of material. An overview of shape-changing-material-actuated large-deflection compliant rotational joints is presented. Performance indicators are proposed to evaluate the existing designs and the prototype. As a case study a compact actuated rotational elbow joint is presented. An antagonistic actuator made from shape memory alloy wires is able to carry an external load and to actuate to move the arm to different positions. The compliant joint is optimized to balance the weight of the arm and to auto-align with the rotational axis of the human elbow joint. A prototype is able to generate a volume specific stall torque of 5.77 ⋅ 10³ Nm/m³, produces a work density of 7.27 ⋅ 10³ J/m³ based on volumes including isolation covers and the half-cycle efficiency of the device is 3.6%. The prototype is able to balance and actuate a torque of 1.1 Nm.

Resilience can be treated as an integrated measure to assess the seismic performance of buildings. Available methods to assess the seismic performance of self-centering structures mainly consider inter-story drift ratios, peak floor accelerations, and energy dissipative capacities, however, their seismic resilience is poorly understood. This paper proposes a framework to estimate the seismic resilience of self-centering energy dissipative braced steel frame office buildings. In this context, a new damage ratio assessment model is presented to assess functionality. Unlike the traditional method that only considers the economic loss or repair time in the functionality assessment, the proposed model accounts for the contribution of four performance measures such as downtime. To estimate the repair cost, repair time, casualties, and unsafe placarding, the FEMA P58 methodology is used. Based on the proposed model, the new damage ratios and recovery times of the self-centering structure are estimated. Obtained damage ratios are combined with fragility analysis to calculate the functionality loss. After considering an appropriate recovery model, seismic resilience is assessed. For comparison, the traditional method (i.e. HAZUS) is also used to assess seismic resilience. The whole framework is applied to a three-story self-centering energy dissipative braced steel frame, and the results show that the traditional method often underestimates the seismic resilience, and the proposed method may be more suitable for predicting the seismic resilience of self-centering energy dissipative braced steel frame office building. Sensitivity analysis is performed to identify uncertain parameters to which seismic resilience is most sensitive, and the result indicates that the control time and damage ratio at the extensive damage state have a major influence on seismic resilience. The framework can be modified and extended to assess the seismic resilience of ordinary building structures and other complex structural systems such as isolated structures.

This paper presents the applications of the spectrogram, Wigner distribution and wavelet transform analysis methods to the second cardiac sound S2 of the phonocardiogram signal (PCG). A comparison between these methods has shown the resolution differences between them. It is found that the spectrogram Short-Time Fourier Transform (STFT) cannot detect the two internals components of the second sound S2 (A2 and P2, atrial and pulmonary components respectively). The Wigner Distribution (WD) can provide time-frequency characteristics of the sound S2, but with insufficient diagnostic information as the two components (A2 and P2) are not accurately detected, appearing to be one component only. It is found that the wavelet transform (WT) is capable of detecting the two components, the aortic valve component A2 and pulmonary valve component P2, of the second cardiac sound S2. However, the standard Fourier transform can display these components in frequency but not the time delay between them. Furthermore, the wavelet transform provides more features and characteristics of the second sound S2 that will hemp physicians to obtain qualitative and quantitative measurements of the time-frequency characteristics.

This paper presents a new urethral valve to deal with severe urinary incontinence (UI) caused by sphincter injury or dysneuria. This valve consists of a wireless power transfer system and a valve body structure driven by SMA (shape memory alloy) spring. The mechanical model of SMA spring and coupling model of wireless energy transfer are derived. Special attention is also given to the biological effects of electromagnetic filed as the proposed device is powered by wireless power transfer system. This valve is validated by simulation experiment and the models are used to investigate the influence of SMA spring parameters, control parameters and coil parameters on the driving characteristics of the proposed urethral valve.

The purpose of this study is to examine the effects of operational and strategic information exchange on supply chain performance and the moderating role of information quality in relation to both operational and strategic information exchange. The study was conducted using manufacturing companies located in the Northern region of Malaysia. Hierarchical multiple regressions were applied to test the hypotheses developed for the study. It was found that operational and strategic information exchange is significantly related to supply chain performance. The impact of strategic information exchange is greater as opposed to operational information exchange. Information quality does not moderate the relationship between both operational and strategic information exchange and supply chain performance. Nonetheless, this study provides evidence that both strategic information exchange and operational information exchange are required to enhance supply chain performance. As such supply chain partners should effectively exchange strategic information as the impact is greater on performance.

Providing recommendations based on distributed data has received an increasing amount of attention because it offers several advantages. Online vendors who face problems caused by a limited amount of available data want to offer predictions based on distributed data collaboratively because they can surmount problems such as cold start, limited coverage, and unsatisfactory accuracy through partnerships. It is relatively easy to produce referrals based on distributed data when privacy is not a concern. However, concerns regarding the protection of private data, financial fears due to revealing valuable assets, and legal regulations imposed by various organizations prevent companies from forming collaborations. In this study, we propose to use random projection to protect online vendors' privacy while still providing accurate predictions from distributed data without sacrificing online performance. We utilize random projection to eliminate the aforementioned issues so vendors can work in partnerships. We suggest privacy-preserving schemes to offer recommendations based on vertically or horizontally partitioned data among multiple companies. The recommended methods are analyzed in terms of confidentiality. We also analyze the superfluous loads caused by privacy concerns. Finally, we perform real data-based trials to evaluate the accuracy of the proposed schemes. The results of our analyses show that our methods preserve privacy, cause insignificant overheads, and offer accurate predictions.