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The main purpose of this study is to investigate the natural convection of micropolar fluid in a square cavity with two orthogonal heaters placed inside. The study of natural convection in a two-dimensional enclosure determines the effect of non-uniform heated plate on certain micropolar fluid flows which are found in many engineering applications. Therefore, because of its practical interest in the engineering fields such as building design, cooling of electronic components, melting and solidification process, solar energy systems, solar collectors, liquid crystals, animal blood, colloidal fluids and polymeric fluids, the topic needs to be further explored.

The dimensionless governing equations have been solved by finite volume method of the second-order central difference and upwind scheme.

The effects of the Rayleigh number, nonuniformity parameter and vortex viscosity parameter on fluid flow and heat transfer have been analyzed. The rate of heat transfer increases with an increase in the aspect ratio of the heated plates for all the values of Rayleigh number and vortex viscosity parameter. The heat transfer rate is reduced with an increase in the vortex viscosity parameter. It is predicted that the non-uniform of the baffle gives better heat transfer than uniform heating.

The present numerical results were tested against the experimental work. The present results have an excellent agreement with the results obtained by the previous experimental work.

With the rapid development of technology in the 21st century, an ever-growing number of organisations are adopting digitalised technologies. The global economy connected with digitalisation is moving towards sustainable development. Individual firms adopt innovative technological strategies to consolidate their position in the competitive market. The study aimed to examine the management perception of the impact of E-commerce adoption (EC) on business performance (BP) – the moderating role of using artificial intelligence (AI).

A quantitative study using the deductive approach and the data collected from senior managers of the small and medium-sized enterprises (SMEs) in Sri Lanka, and 389 samples were collected using a simple random sampling method. EC, BP and AI were named as the independent, dependent and moderating variables in the model. Porters' generic strategies and resource-based views (RBVs) were applied as the foundation of the study.

The independent and moderating variables significantly influenced the BP. Managers' age, gender, education level and job position affect their perception.

The global economy is moving towards sustainable development using digitalisation. The firms should blend their strategies with digitalised platforms to survive in the competitive market.

The peer review history for this article is available at the following link: https://publons.com/publon/10.1108/IJSE-12-2021-0752

Aluminium and its alloys are the most preferred material in aerospace and automotive industries because of their high strength-to-weight ratio. However, these alloys are found to be low wear resistance. Hence, the incorporation of ceramic particles with the aluminium alloy may be enhanced the mechanical and tribological properties. The purpose of this study is to optimize the specific wear rate and friction coefficient of titanium dioxide (TiO₂) reinforced AA7075 matrix composites. The four wear control factors are considered, i.e. reinforcement (Wt.%), applied load (N), sliding velocity (m/s) and sliding distance (m).

The composites were fabricated through stir casting route with varying weight percentages (0, 5, 10 and 15 Wt.%) of TiO₂ particulates. The mechanical properties of the composites were studied. The specific wear rate and friction coefficient of the newly prepared composites was determined by using a pin-on-disc apparatus under dry sliding conditions. Experiments were planned as per Taguchi’s L16 orthogonal design. Signal-to-noise ratio analysis was used to find the optimal combination of parameters.

The mechanical properties such as yield strength, tensile strength and hardness of the composites significantly improved with the addition of TiO₂ particles. The analysis of variance result shows that the applied load and reinforcement Wt.% are the most influencing parameters on specific wear rate and friction coefficient during dry sliding conditions. The scanning electron microscope morphology of the worn surface shows that TiO₂ particles protect the matrix from more removal of material at all conditions.

This paper provides a solution for optimal parameters on specific wear rate and friction coefficient of aluminium matrix composites (AMCs) using Taguchi methodology. The obtained results are useful in improving the wear resistance of the AA7075-TiO₂ composites.

The Fay and Riddell (F–R) formula is an empirical equation for estimating the stagnation-point heat flux on noncatalytic and fully catalytic surfaces, based on an assumption of equilibrium. Because of its simplicity, the F–R has been used extensively for reentry flight design as well as ground test facility applications. This study aims to investigate the uncertainties of the F-R formula by considering velocity gradient, chemical species at the boundary layer edge, and the thermochemical nonequilibrium (NEQ) behind the shock layer under various hypersonic NEQ flow environments.

The stagnation-point heat flux calculated with the F–R formula was evaluated by comparison with thermochemical NEQ calculations and existing flight experimental values.

The comparisons showed that the F–R underestimated the noncatalytic heat flux, because of the chemical composition at the surface. However, for fully catalytic heat flux, the F–R results were similar to values of surface heat flux from thermochemical NEQ calculations, because the F–R formula overestimates the diffusive heat flux. When compared with the surface heat flux results obtained from flight experimental data, the F–R overestimated the fully catalytic heat flux. The error was 50% at most.

The results provided guidelines for the F–R calculations under hypersonic flight conditions and for determining the approximate error range for noncatalytic and fully catalytic surfaces.

The purpose of this paper is to build a mobile visual search service system for the protection of Dunhuang cultural heritage in the smart library. A novel mobile visual search model for Dunhuang murals is proposed to help users acquire rich knowledge and services conveniently.

First, local and global features of images are extracted, and the visual dictionary is generated by the k-means clustering. Second, the mobile visual search model based on the bag-of-words (BOW) and multiple semantic associations is constructed. Third, the mobile visual search service system of the smart library is designed in the cloud environment. Furthermore, Dunhuang mural images are collected to verify this model.

The findings reveal that the BOW_SIFT_HSV_MSA model has better search performance for Dunhuang mural images when the scale-invariant feature transform (SIFT) and the hue, saturation and value (HSV) are used to extract local and global features of the images. Compared with different methods, this model is the most effective way to search images with the semantic association in the topic, time and space dimensions.

Dunhuang mural image set is a part of the vast resources stored in the smart library, and the fine-grained semantic labels could be applied to meet diverse search needs.

The mobile visual search service system is constructed to provide users with Dunhuang cultural services in the smart library. A novel mobile visual search model based on BOW and multiple semantic associations is proposed. This study can also provide references for the protection and utilization of other cultural heritages.

The purpose of this paper is to carry out a detailed analysis of two port converter fed by Solar and wind sources during different operational modes by small signal modelling. The converter is fully characterized and simulated using Matlab/Simulink. The voltage and current waveforms along with their corresponding expressions describing the converter operation are presented in detail. Then the DC-averaged equivalent topology is derived using circuit averaging technique. A complete derivation of the power stage transfer functions relevant to the capacitor voltage loop, such as capacitor voltage to solar voltage and inductor current to wind input voltage is obtained.

Stability analysis is used to analyze the small deviations around the steady-state operating point which helps in modeling the closed loop converter parameters. This paper presents the analysis, modeling and control of two port Cuk-buck converter topology.

Based on the results, a control strategy is designed to manage the energy flow within the system. A lab-level prototype for Cuk-buck converter with PWM controller is implemented and tested under various input conditions to study the performance of the converter during seasonal changes. The simulation and experimental results showed that effective operation and control strategy of the hybrid power supply system managed to be achieved alongside its feasible outputs.

This analysis can be extended to all power electronic converters and will be useful for the design of controllers.

An appropriate control design plays a key role in enhancing the overall performance of the system. Hence, this paper is intended to present in detail the small signal modeling of the Cuk-buck converter along with the control design for all the switching modes.

Though this type of converter topology has been discussed widely in literature, very scarce literature is available related to modeling and control design of the converter. A state-space averaging model of the converter followed by a type-II compensator design is described, and prototype design and experimental results are also presented.

The purpose of this study is to analyse and optimize the wear parameters of magnesium metal-metal composite. Materials with lesser weight attract both the researcher and industrialists, as it exhibits the performance improvement in the automotive and aerospace industries. The enrichment of mechanical and tribological properties of the existing magnesium focussed the development of new metal–metal composite.

Metal–metal composite with magnesium matrix was synthesized through the disintegrated melt deposition technique with the addition of titanium, aluminium and boron carbide particles. The wear performance of the composite was experimented with the dry sliding wear test by considering load, sliding velocity and sliding distance.

The wear rate of the composite is analysed statistically, and the significance of wear parameters on the wear performance of metal–metal composite is observed. The worn pin surface and the wear debris collected during the wear experiments were exposed to the microscopy analysis to seize the dominating wear mechanisms.

The wear performance of the developed magnesium composite was analysed and discussed in detail with the support of scientific evidence, i.e. worn surface and debris analysis express the wear mechanisms.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2019-0326/

The Gaza Strip in Palestine is suffering from a shortage of water and energy. To manage the current situation and address future issues, practical approaches need to be adopted to enhance water and energy efficiency. The purpose of this paper is to elicit professionals’ perceptions of the drivers affecting water and related energy consumption in residential buildings in the Gaza Strip.

In total, 19 drivers were identified from previous research and modified according to the results of a pilot study. These drivers were ranked under a Relative Importance Index (RII). A questionnaire survey was then administered and non-random purposive sampling used. The population of this study comprised stakeholders, including the United Nation Refugee Work Agency, Gaza Strip Governorates Municipalities, and the Coastal Municipalities Water Utility.

The results of all drivers (i.e. RII=71.43 per cent, mean=3.57) indicated that the respondents agreed about which drivers were affecting water and energy consumption. The sign Test-value was a positive 4.55 and the p-value was 0.000 (i.e. smaller than the level of significance a=0.050). The means of these drivers differed significantly and were greater than the hypothesised value of 3. Accordingly, it was concluded that the drivers investigated significantly affected household residents’ consumption of water and energy in residential buildings. The study revealed that climate changes, knowledge of how to conserve water and energy and household size were the most important drivers affecting household residents’ consumption of water and related energy in residential buildings.

The study will assist the parties concerned about water and energy use to be aware and understand the drivers affecting water and related energy the consumption in order to provide household residents with the necessary knowledge to ensure conservation and sustainability. Although this study related to a narrow geographical area in Palestine, the findings could be useful to similar locations in the Middle East and Africa.

This research demonstrates the drivers affecting water and related energy the consumption in residential buildings in the Gaza Strip which is considered the first study in Palestine and in the region. The study provides a useful platform for the development of appropriate water and energy strategies in Palestine and other similar geographical locations in the Middle East.

This paper aims to discuss the results of the performance study of wind turbine blades equipped with winglets. An investigation focusses on small wind turbines (SWTs), where the winglets are recalled as one of the most promising concepts in terms of turbine efficiency increase.

To investigate a contribution of winglets to SWT aerodynamic efficiency, a wind tunnel experiment was performed at Lodz University of Technology. In parallel, computational fluid dynamics (CFD) simulations campaign was conducted with the ANSYS CFX software to investigate appearing flow structures in greater detail.

The research indicates the potential behind the application of winglets in low Reynolds flow conditions, while the CFD study enables the identification of crucial regions influencing the flow structure in the most significant degree.

As the global effect on a whole rotor is a result of a small-scale geometrical feature, it is important to localise unveiled phenomena and the mechanisms behind their generation.

Even the slightest efficiency improvement in a distributed generation installation can promote such a solution amongst energy prosumers and increase their independence from limited natural resources.

The winglet-equipped blades of SWTs provide an opportunity to increase the device performance with relatively low cost and ease of implementation.

In-situ aluminum metal matrix composites (AMMC) have taken over the use of ex-situ AMMC due to the generation of finer and thermodynamically stable intermetallic compounds. However, conventional processing routes pose inevitable defects like porosity and agglomeration of particles. This paper aims to study current state of progress in in-situ AMMC fabricated by Friction Stir Processing.

Friction stir processing (FSP) has successfully evolved to be a favorable in-situ composite manufacturing technique. The dynamics of the process account for a higher plastic strain of 35 and a strain rate of 75 per second. These processing conditions are responsible for grain evolution from rolled grain → dislocation walls and dislocation tangles → subgrains → dislocation multiplication → new grains. Working of matrix and reinforcement under ultra-high strain rate and shorter exposure time to high temperatures produce ultra-fine grains. Do the grain evolution modes include subgrain boundaries → subgrain boundaries and high angle grain boundaries → high angle grain boundaries.

Further, the increased strain and strain rate can shave and disrupt the oxide layer on the surface of particles and enhance wettability between the constituents. The frictional heat generated by tool and workpiece interaction is sufficient enough to raise the temperature to facilitate the exothermic reaction between the constituents. The heat released during the exothermic reaction can even raise the temperature and accelerate the reaction kinetics. In addition, heat release may cause local melting of the matrix material which helps to form strong interfacial bonds.

This article critically reviews the state of the art in the fabrication of in-situ AMMC through FSP. Further, FSP as a primary process and post-processing technique in the synthesis of in-situ AMMC are also dealt with.