In this work, experiments were carried out to quantify the behaviour of friction stir welded (FSW) AA5082-AA7075 butt joints under tensile loading and completely reversed fatigue loading. Different samples were prepared to identify optimum tool rotational and travel speeds to produce FSW AA5082-AA7075 butt joints with the maximum fatigue life. ANOVA was performed, which confirmed that both tool speed and tool rotational speed affect the tensile strength of the weld. The samples exhibit a considerable difference in their fatigue life and tensile strength. This difference can be accounted to the presence of welding defects such as surface defects and porosity. S-N curve plotted for the sample shows a significantly high fatigue life at the lower stress ranges. Fracture surfaces were also analysed under scanning electron microscope (SEM). Study of the fracture surface of the sample that failed under fatigue loading showed that the surface was mainly divided in two zones. The first zone was the area of fatigue crack growth where each stress cycle, slowly and gradually, helped in the growth of the crack. The second zone was the region of fast fracture where the crack growth resulted in the failure of the joint instantaneously. The fracture surface study of the sample that failed under tensile loading showed that the mode of failure was ductile in nature.

In this paper, a comprehensive study is carried out on the dynamic behaviour of Euler–Bernoulli and Timoshenko beams resting on Winkler type variable elastic foundation. The material properties of the beam and the stiffness of the foundation are considered to be varying along the length direction. The free vibration problem is formulated using Rayleigh-Ritz method and Hamilton’s principle is applied to generate the governing equations. The results are presented as non-dimensional natural frequencies for different material gradation models and different foundation stiffness variation models. Two distinct boundary conditions viz., clamped-clamped and simply supported-simply supported are considered in the analysis. The results are validated with existing literature and excellent agreement is observed between the results.

Providing roughness is an effective method to heat fluids to high temperature. Present paper make use of concave dimple roughness on one and three sides of roughened ducts aimed at determining rise in heat transfer and friction of three sides over one side roughened duct. Three sides roughened duct produces high heat transfer compared to one side roughened. Results are shown as a rise in Nusselt number and friction factor of three sides over one side roughened duct. Experimental investigation was conducted under actual outdoor condition at National Institute of Technology Jamshedpur, India to test various sets of roughened collectors. Roughness parameter varied as relative roughness pitch 8–15, relative roughness height 0.018–0.045, dimple depth to diameter ratio 1–2, Reynolds number 2500–13500 at fixed aspect ratio (width/hight) 8. Highest enhancement in Nusselt number for varying relative roughness pitch, height, and diameter ratio was respectively found as 2.6 to 3.55 times, 1.91 to 3.42 times and 3.09 to 3.94 times compared to one side dimple roughened duct. Highest rise in friction for three sides over one side roughened duct for these varying parameters was respectively found as 1.62 to 2.79 times, 1.52 to 2.34 times and 2.21 to 2.56 times. To visualize the effect of roughness parameter on heat transfer and friction factor, variation in Nusselt number and friction factor for varying roughness parameters with Reynolds number is shown.

The optimal energy management (OEM) in a stand-alone microgrid (SMG) is a challenging job because of uncertain and intermittent behavior of clean energy sources (CESs) such as a photovoltaic (PV), wind turbine (WT). This paper presents the effective role of battery energy storage (BES) in optimal scheduling of generation sources to fulfill the load demand in an SMG under the intermittency of theWT and PV power. The OEM is performed by minimizing the operational cost of the SMG for the chosen moderate weather profile using an artificial bee colony algorithm (ABC) in four different cases, i.e. without the BES and with the BES having a various level of initial capacity. The results show the efficient role of the BES in keeping the reliability of the SMG with the reduction in carbon-emissions and uncertainty of the CES power. Also, prove that the ABC provides better cost values compared to particle swarm optimization (PSO) and a genetic algorithm (GA). Further, the robustness of system reliability using the BES is tested for the mean data of the considered weather profile.

This paper explores the parametric appraisal and machining performance optimization during drilling of polymer nanocomposites reinforced by graphene oxide/carbon fiber. The consequences of drilling parameters like cutting velocity, feed, and weight % of graphene oxide on machining responses, namely surface roughness, thrust force, torque, delamination (In/Out) has been investigated. An integrated approach of a Combined Quality Loss concept, Weighted Principal Component Analysis (WPCA), and Taguchi theory is proposed for the evaluation of drilling efficiency. Response surface methodology was employed for drilling of samples using the titanium aluminum nitride tool. WPCA is used for aggregation of multi-response into a single objective function. Analysis of variance reveals that cutting velocity is the most influential factor trailed by feed and weight % of graphene oxide. The proposed approach predicts the outcomes of the developed model for an optimal set of parameters. It has been validated by a confirmatory test, which shows a satisfactory agreement with the actual data. The lower feed plays a vital role in surface finishing. At lower feed, the development of the defect and cracks are found less with an improved surface finish. The proposed module demonstrates the feasibility of controlling quality and productivity factors.

The problem of improving the voltage profile and reducing power loss in electrical networks must be solved in an optimal manner. This paper deals with comparative study of Genetic Algorithm (GA) and Differential Evolution (DE) based algorithm for the optimal allocation of multiple FACTS (Flexible AC Transmission System) devices in an interconnected power system for the economic operation as well as to enhance loadability of lines. Proper placement of FACTS devices like Static VAr Compensator (SVC), Thyristor Controlled Switched Capacitor (TCSC) and controlling reactive generations of the generators and transformer tap settings simultaneously improves the system performance greatly using the proposed approach. These GA & DE based methods are applied on standard IEEE 30 bus system. The system is reactively loaded starting from base to 200% of base load. FACTS devices are installed in the different locations of the power system and system performance is observed with and without FACTS devices. First, the locations, where the FACTS devices to be placed is determined by calculating active and reactive power flows in the lines. GA and DE based algorithm is then applied to find the amount of magnitudes of the FACTS devices. Finally the comparison between these two techniques for the placement of FACTS devices are presented.

This article concerns fully developed laminar flow of a viscous incompressible fluid in a long composite cylindrical channel. Channel consist of three regions. Outer and inner regions are of uniform permeability and mid region is a clear region. Brinkman equation is used as a governing equation of motion in the porous region and Stokes equation is used for the clear fluid region. Analytical expressions for velocity profiles, rate of volume flow and shear stress on the boundaries surface are obtained and exhibited graphically. Effect of permeability variation parameter on the flow characteristics has been discussed.

Over the years laser welding has evolved as a fabrication process capable of overcoming the limitations of conventional joining methodologies. It facilitates the welding of diverse range of materials like metals, non-metals, polymers etc. Laser transmission welding is a technique employed for fabricating intricate shapes/contours in polymers with better precision compared to the other conventional processes. Nylon6, a synthetic semi-crystalline polymer is utilized as an engineering thermoplastic due to its high strength and temperature resistant properties. In the earlier researches, various welding techniques were employed for the fabrication of polymers and metals keeping the laser beam stagnant, and much emphasis was given only to temperature distribution along the different axes and limited attention was given to residual stress analysis. Therefore, in this research work, a three-dimensional time-dependent model using a moving laser beam is used to fabricate unreinforced Nylon6 specimens.

Indian SMEs are going to play pivotal role in transforming Indian economy and achieving

double digit growth rate in near future. Performance of Indian SMEs is vital in making

India as a most preferred manufacturing destination worldwide under India’s “Make in India

Policy”. Current research was based on Indian automotive SMEs. Indian automotive SMEs

must develop significant agile capability in order to remain competitive in highly uncertain

global environment. One of the objectives of the research was to find various enablers of

agility through literature survey. Thereafter questionnaire administered exploratory factor

analysis was performed to extract various factors of agility relevant in Indian automotive

SMEs environment. Multiple regression analysis was applied to assess the relative importance

of these extracted factors. “Responsiveness” was the most important factor followed by

“Ability to reconfigure”, “Ability to collaborate”, and “Competency”. Thereafter fuzzy logic

bases algorithm was applied to assess the current level of agility of Indian automotive SMEs.

It was found as “Slightly Agile”, which was the deviation from the targeted level of agility.

Fuzzy ranking methodology facilitated the identification & criticalities of various barriers

to agility, so that necessary measures can be taken to improve the current agility level of

Indian automotive SMEs. The current research may helpful in finding; key enablers of agility,

assessing the level of agility, and ranking of the various enablers of agility to point out the

weak zone of agility so that subsequent corrective action may be taken in any industrial

environment similar to India automotive SMEs.

Mycoherbicides are special biotechnology products which contain fungi or fungal metabolites as nonchemical alternatives thereby reducing the input of harmful chemicals to control noxious weeds. The present communication emphasizes on the potential of an indigenous isolate of Alternaria alternata ITCC 4896 as a mycoherbicide for the global weed – Parthenium hysterophorus. Of the various spore concentrations tested by in vitro Detached Leaf Bioassay, 1x10⁶ spores/ml was the most effective inducing 89.2% leaf area damage on the 7th day and was further tested by Whole Plant Bioassay. Both in vitro Detached Leaf Bioassay and Whole Plant Bioassay exhibited a similar trend in disease development showing 50% damage at 96 hours post treatment. However, 100% mortality was observed in the Whole Plant Bioassay on the 7th day. This is the very first report on the bioweedicidal potential of A. alternata ITCC 4896 (LC#508) for use as a mycoherbicide for P. hysterophorus.

Transmission line loss minimization in a power system is an important research issue and it can be achieved by means of reactive power compensation. The unscheduled increment of load in a power system has driven the system to experience stressed conditions. This phenomenon has also led to voltage profile depreciation below the acceptable secure limit. The significance and use of Flexible AC Transmission System (FACTS) devices and capacitor placement is in order to alleviate the voltage profile decay problem. The optimal value of compensating devices equires proper optimization technique, able to search the optimal solution with less computational burden. This paper presents a technique to provide simultaneous or individual controls of basic system parameter like transmission voltage, impedance and phase angle, thereby controlling the transmitted power using Unified Power Flow Controller (UPFC) based on Bacterial Foraging (BF) algorithm. Voltage stability level of the system is defined on the Fast Voltage Stability Index (FVSI) of the lines. The IEEE 14-bus system is used as the test system to demonstrate the applicability and efficiency of the proposed system. The test result showed that the ocation of UPFC improves the voltage profile and also minimize the real power loss.

MIMO technology has become very popular in a wireless communication system because of the many advantages of multiple antennas at the transmitting end and receiving end. The main advantages of MIMO systems are higher data rate and higher reliability without the need of extra power and bandwidth. The MIMO system provides higher data rate by using spatial multiplexing technique and higher reliability by using diversity technique. The MIMO systems have not only advantages, but also have disadvantages. The main disadvantage of MIMO system is that the multiple antennas required extra high cost RF modules. The extra RF modules increase the cost of wireless communication systems. In this research, the antenna selection techniques are proposed to minimize the cost of MIMO systems. Furthermore, this research also presents techniques for antenna selection to enhance the capacity of channel in MIMO systems.

Multiple input multiple output (MIMO) is a multiple antenna technology used extensively in wireless communication systems. With the ever increasing demand in high data rates, MIMO system is the necessity of wireless communication. In MIMO wireless communication system, where the multiple antennas are placed on base station and mobile station, the major problem is the constant power of base station, which has to be allocated to data streams optimally. This problem is referred as a power allocation problem. In this research, singular value decomposition (SVD) is used to decouple the MIMO system in the presence of channel state information (CSI) at the base station and forms parallel channels between base station and mobile station. This practice parallel channel ensures the simultaneous transmission of parallel data streams between base station and mobile station. Along with this, water filling algorithm is used in this research to allocate power to each data stream optimally. Further the relationship between the channel capacity of MIMO wireless system and the number of antennas at the base station and the mobile station is derived mathematically. The performance comparison of channel capacity for MIMO systems, both in the presence and absence of CSI is done. Finally, the effect of channel correlation because of antennas at the base stations and the mobile stations in the MIMO systems is also measured.