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This paper aims to investigate the cycle performance of a small size turbojet engine used in unmanned aerial vehicles at 0–5,000 m altitude and 0–0.8 Mach flight speeds with real component maps.

The engine performance calculations were performed for both on-design and off-design conditions through an in-house code generated for simulating the performance of turbojet engines at different flight regimes. These calculations rely on input parameters in which fuel composition are obtained through laboratory elemental analysis.

Exemplarily, according to comparative results between in-house developed performance code and commercially available software, there is 0.25% of the difference in thrust value at on-design conditions.

Once the on-design performance parameters and fluid properties were determined, the off-design operation calculations were performed based on the compressor and turbine maps and scaling methodology. This method enables predicting component maps and fitting them to real conditions.

A method to be used easily by researchers on turbojet engine performance calculations which best fits to real conditions.

The purpose of this research is to present an integrated methodological framework to aid in performance stewardship of management institutions according to their strategies based on a holistic evaluation encompassing social, economic and environmental dimensions.

A Mamdani fuzzy inference system (FIS) approach was adopted to design the quantitative models with respect to balanced scorecard (BSC) perspectives to demonstrate dynamic capability. Individual models were developed for each perspective of BSC using Mamdani FIS. Data was collected from subject matter experts in management education.

The proposed methodology is able to successfully compute the scores for each perspective. Effective placement, teaching learning process, faculty development and systematic feedback from the stakeholders were found to be the key drivers for revenue generation. The model is validated as the results were well accepted by the head of the institution after implementation.

The model resulting from this study will assist the institution to cyclically assess its performance, thus enabling continuous improvement. The strategy map provides the causality of the objectives across the four perspectives to aid the practitioners to better strategize. Also this study contributes to the literature of BSC as well to the applications of multi-criteria decision-making (MCDM) techniques.

Mamdani FIS integrated BSC model is a significant contribution to the academia of management education to quantitatively compute the performance of institutions. This quantified model reduces the ambiguity for practitioners to decide the performance levels for each metric and the priorities of metrics.

Total quality management (TQM) is a process and philosophy to achieve customer satisfaction in long term by improving the products, processes and services effectively and efficiently. TQM implementation is turning into a complex practice due to the increasing number of effective factors and key elements labelled as critical success factors (CSFs). The purpose of this paper is to analyse the relations between CSFs of TQM and to provide decision makers has a clear picture of relations by determining the most affecting – both the number of CSFs which this factor affects and the its effect degree on relevant CSFs are higher comparing to other factors – of this factors affected factors – both the number of CSFs and their effect degree on these factors are higher – that influences a successful TQM implementation.

The paper refers to fuzzy cognitive maps (FCMs) that allow dynamic modelling of a system in consideration of a complex network structure and the effects of factors to each other. The method demonstrates causal representations between CSFs under uncertainty to represent the relations and interaction between them and performs qualitative simulations to analyse the factors that have the highest impact on continuous improvement of quality management process. The evaluations are performed by five academicians whose professions are on both the areas of TQM and FCM.

FCM analysis shows how the most affecting and affected factors influence the other CSF in order to manage a successful TQM implementation.

The critical factors of TQM implementation are in the focus of most of the empirical studies in the literature. However, none of them considers the dynamic interactions between the factors. This study employs FCM to explore the CSFs that influence the TQM implementation process considering the relations among them to observe the most affecting and affected factors based on the changes of determined CSFs.

This study aims to investigate the tribological performance of neat polyamide-imide (PAI) and PAI composite (PAI + 12% graphite + 3% polytetrafluoroethylene [PTFE]) under varying mediums and conditions, including dry sliding, distilled water and seawater lubrication, to determine their suitability for high-stress applications.

Tribological tests were conducted using a pin-on-disc setup with AISI 316 L stainless steel (SS) as counterface. Experiments were carried out under loads of 150 and 300 N and sliding speeds of 1.5 and 3.0 m/s. Values of temperatures, friction coefficients and wear rates were recorded to analyze the effect of fillers and lubrication mediums.

The PAI composite outperformed the neat PAI under all conditions, showing significant reductions in friction coefficients and wear rates. Seawater lubrication yielded the best results, achieving friction coefficients of 0.05 and 0.01 and specific wear rates of 18.10⁻¹⁶ m²/N and 1.10 ⁻¹⁵ m²/N, for neat PAI and PAI composite, respectively. Graphite and PTFE fillers enhanced lubrication, reduced surface temperatures and mitigated abrasive and adhesive wear mechanisms. Superior cooling and lubrication effects of the seawater contributed to these improvements.

Previous studies mainly focused on dry sliding and distilled water lubrication for the PAI and its composites, with no research on the seawater conditions. This study compares the tribological behaviors of the neat PAI and PAI composite against AISI 316 L SS under dry sliding, distilled water and seawater lubrication.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2024-0302/

The main purpose of the present study was to evaluate the metallurgical and mechanical properties of dissimilar metal friction welds (FWs) between aluminium and type 304 stainless steel.

One of the manufacturing methods used to produce parts made from different materials is the FW method. Therefore, in the present study, austenitic stainless steel and aluminium parts were joined by FW. Tensile, fatigue and notch-impact tests were applied to FW specimens, and the results were compared with those for the original materials. Microstructure, energy dispersive X-ray (EDX) and X-ray diffraction (XRD) analysis and hardness variations were conducted on the joints.

It was found from the microstructure and XRD analysis that inter-metallic phases formed in the interface which further caused a decrease in the strength of the joints.

In this study, the rotation speed was kept constant. The effects of the rotation speed on the welding quality can be examined in future. It is important to note that the FW process was successfully accomplished in this study although it was particularly difficult to obtain the weld due to the large deformations at the interface.

Low-density components such as aluminium and magnesium can be joined with steels owing to being cost-effective in industry. Application of classical welding techniques to such materials is difficult because they have different thermal properties. Their welding plays a key part in industrial quality and process control, in the efficient use of energy and other resources, in health and safety. Then, this study will contribute for welded, brazed and soldered materials.

The main value of this paper is to contribute and fulfill the influence of the interface on properties in welding of various materials that is being studied so far in the literature.

The purpose of this paper is to assess a comprehensive model that computes a single score in order to evaluate the sustainability of the municipal solid waste management (MSWM) system of a given city. The model was applied to calculate the sustainability index for the MSWM of Istanbul, Turkey as a case study.

Different sustainability indicators (including environmental, economical, and social parameters) along with exergy analysis were integrated to utilize an analytical hierarchy process (AHP) under a life cycle perspective.

The Istanbul case study helped to verify that AHP is an effective and efficient decision-making tool. According to the analysis, the current MSWM system of Istanbul is sustainable, and the sustainability can be improved only by changing the amounts to be treated by the current system without any new technological investments.

The Municipal Solid Waste Management Sustainability Index (MSWMSI) in this study allowed to integrate large amount of information on interrelated parameters and the sustainability indicators in the whole life cycle into one value that is useful for a general or a comparative judgment and helpful in MSWM decision making.

The fact that the weighting assigned to each component in the model is dependent on the decision makers’ evaluations enables the model to be tailored to any city of concern. The model allows the user to readily determine the relative contribution of each criterion or sub-criterion to the final MSWM selection. It is convenient to use and the computations can be run utilizing available specialized software as well as computing by hand.