Influence of friction stir processing parameters on surface modified 90Cu-10Ni composites

Friction Stir Processing (FSP) has emerged as a distinctive and pioneering solid state technique to produce surface composites. The objective of the present research is to produce reinforced 90/10 Copper–Nickel surface composites with different carbide-based ceramic particles through FSP and study the relationship of its dynamic parameters including tool rotational speed, tool traverse speed, and width of the groove over the surface behavior. Responses such as sliding wear, microhardness, and surface modified area in the friction stir processed region are modeled using polynomial, nonlinear, multiple regression based on the central composite design of experiment. Analysis of the developed models showed that the FSP parameters; traverse speed, rotational speed, and groove width have significant influence on both the sliding wear and microhardness of developed surface composite. And furthermore, tool rotational speed and tool traverse speed, simultaneously control dispersion of reinforcement in the surface. To validate the abovementioned noteworthy results and to study the microstructural aspects, selected specimens were carried over metallurgical analysis and the obtained results were put forward in detail in this paper.     

Prediction of Delta Ferrite Content and Effect of Welding Process Parameters in Claddings by FCAW

This article discusses the influence of welding process parameters on the content of delta ferrite in the claddings of AISI 317L, deposited onto IS: 2062 structural steel plate by the flux cored arc welding (FCAW) process. Measurement of delta ferrite within the cladding often gives important insight into the future mechanical and corrosion resistant behavior of the cladded structures. To predict and control the amount of residual ferrite, regression models were developed in terms of process parameters, using the data obtained from experiments. The experiments were conducted by using a central composite rotatable design of experiments. The study revealed that the cladding process parameters have influence over the formation of delta ferrite.     

Energy‐Efficient Quorum‐Based MAC Protocol for Wireless Sensor Networks

The reliability of sensor networks is generally dependent on the battery power of the sensor nodes that it employs; hence it is crucial for the sensor nodes to efficiently use their battery resources. This research paper presents a method to increase the reliability of sensor nodes by constructing a connected dominating tree (CDT), which is a subnetwork of wireless sensor networks. It detects the minimum number of dominatees, dominators, forwarder sensor nodes, and aggregates, as well as transmitting data to the sink. A new medium access control (MAC) protocol, called Homogenous Quorum‐Based Medium Access Control (HQMAC), is also introduced, which is an adaptive, homogenous, asynchronous quorum‐based MAC protocol. In this protocol, certain sensor nodes belonging to a network will be allowed to tune their wake‐up and sleep intervals, based on their own traffic load. A new quorum system, named BiQuorum, is used by HQMAC to provide a low duty cycle, low network sensibility, and a high number of rendezvous points when compared with other quorum systems such as grid and dygrid. Both the theoretical results and the simulation results proved that the proposed HQMAC (when applied to a CDT) facilitates low transmission latency, high delivery ratio, and low energy consumption, thus extending the lifetime of the network it serves.     

An efficient anonymous authentication and confidentiality preservation schemes for secure communications in wireless body area networks

Wireless body area network (WBAN) is utilized in various healthcare applications due to its ability to provide suitable medical services by exchanging the biological data between the patient and doctor through a network of implantable or wearable medical sensors connected in the patients’ body. The collected data are communicated to the medical personals through open wireless channels. Nevertheless, due to the open wireless nature of communication channels, WBAN is susceptible to security attacks by malicious users. For that reason, secure anonymous authentication and confidentiality preservation schemes are essential in WBAN. Authentication and confidentiality play a significant role while transfers, medical images securely across the network. Since medical images contain highly sensitive information, those images should be transferred securely from the patients to the doctor and vice versa. The proposed anonymous authentication technique helps to ensure the legitimacy of the patient and doctors without disclosing their privacy. Even though various cryptographic encryption techniques such as AES and DES are available to provide confidentiality, the key size and the key sharing are the main problems to provide a worthy level of security. Hence, an efficient affine cipher-based encryption technique is proposed in this paper to offer a high level of confidentiality with smaller key size compared to existing encryption techniques. The security strength of the proposed work against various harmful security attacks is proven in security analysis section to ensure that it provides better security. The storage cost, communication cost and computational cost of the proposed scheme are demonstrated in the performance analysis section elaborately. In connection to this, the computational complexity of the proposed scheme is reduced around 29% compared to the existing scheme.

     

Influence of tool pin profile on the metallurgical and mechanical properties of friction stir welded Al–10 wt.% TiB2 metal matrix composite

In the present work, Al–10 wt.% TiB₂ metal matrix composites (MMCs) are joined using friction stir welding (FSW) process. Different tool pin profiles are developed to weld the MMCs and the effect of tool pin profile on metallurgical and mechanical properties of the weldments are studied. The stirred zones of MMCs joined with taper pin profiles are narrower than that are joined with straight pin profiles. Weld nugget has finer grains compared to other weld zones and TiB₂ particulates are homogeneously present in Al matrix both in weld and parent metal. The effect of pin profiles on mechanical properties are analyzed and it is found that joints welded with straight square pin profile have better mechanical properties compared to the other pin profiles.     

Developing an Empirical Relationship to Predict the Influence of Process Parameters on Tensile Strength of Friction Stir Welded AA6061/0–10 wt% ZrB2 In Situ Composite

New families of aluminum matrix composites (AMCs) have been developed over the last decade in search of superior properties. Aluminum reinforced with ZrB₂ particles is one such family which has drawn the attention of researchers. Friction stir welding is a relatively new solid state welding which overcomes most of the defects associated with fusion welding of AMCs. An attempt has been made to friction stir weld AA6061/0?C10 wt% ZrB₂ in situ composite and to develop an empirical relationship to predict the tensile strength of butt joints. Four factors, five levels central composite rotatable design was used to minimize the number of experiments. The factors considered are tool rotational speed, welding speed, axial force and weight percentage of ZrB₂. The effect of these factors on tensile strength of the welded joints is analyzed using the developed empirical relationship. The predicted trends are discussed. It is observed that the factors independently influence the tensile strength over the entire range of parameters studied in this work.     

Influence of FCA Welding Process Parameters on Distortion of 409M Stainless Steel for Rail Coach Building

The influence of flux cored arc welding (FCAW) process parameters such as welding current, travel speed, voltage and CO2 shielding gas flow rate on bowing distortion of 409M ferritic stainless steel sheets of 2 mm in thickness was discussed. The bowing distortions of the welded plates were measured using a simple device called profile tracer. An experimental regression equation was developed to predict the bowing distortion and with this equation, it is easy to select optimized process parameters to achieve minimum bowing distortion. It is revealed that the FCAW process parameters have significant influence on bead profile and the bowing distortion.