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The purpose of this paper is to present the idea of automatic flight control algorithms capable of performing an Immelmann turn manoeuvre automatically. This is a case of a manoeuvre far removed from so-called standard flight. The character of this manoeuvre and the range of changes in the aircraft flight parameters restrict the application of standard control algorithms. Furthermore, the possibility of acquiring full and detailed information about the aircraft’s flight parameters is limited in such cases. This paper seeks to analyse an alternative solution that can be applied in some specific cases.

This paper uses theoretical discussion and breakdowns to create the basics for development of structures of control algorithms. A simplified analytical approach was applied to tune regulators and the results of the research were verified in a series of software-in-the loop computer simulations.

The structure of the control system enabling aerobatic flight (with the Immelmann turn as the selected example) was identified and the method for tuning the regulators is also presented.

It could serve as a foundation for autopilots working in non-conventional flight states and aircraft automatic recovery systems.

This paper presents the author’s original approach to aircraft automatic control when high control precision is not the priority and not all flight parameters can be precisely measured.

The purpose of this paper is to present a methodology to assess material damage parameters for ductile crack initiation and growth ahead of a crack/notch tip in high hardening steel like AISI type 316L(N) stainless steel.

Ductile damage parameter and far field J-integral have been obtained from standard FEM analysis for a crack/notch tip undergoing large plastic deformation and resulting in crack initiation/growth. In conjunction with experimental results, the damage variable for low strength and high hardening material has been derived in terms of continuum parameters: equivalent plastic strain (ε_eq) and stress triaxiality (φ). The material parameters for damage initiation and growth in 316LN SS have been evaluated from tensile and fracture tests. With these material tensile/fracture parameters as input, elastic-plastic eXtended Finite Element Method (X-FEM) simulations were carried out on compact tension (CT) specimen geometry under varying initial stress triaxiality conditions.

The material parameters for damage initiation and growth have been assessed and calibrated by comparing the X-FEM predicted load-displacement responses with the experimental results. It is observed that the deviations in the predicted load values from the experimental data are within 6 percent for specimens with a/W=0.39, 0.55, 0.64, while for a/W=0.72, it is 17 percent.

The present study is a part of developing methods to obtain calibrated material damage parameters for crack growth simulation of components made of AISI 316L(N) stainless steel. This steel is used for fast breeder reactor-based power plant being built at Kalpakkam, India.

The purpose of this paper is to investigate the change in management accounting and control systems (MACSs) within two large public manufacturing companies in Libya so-called Trucks and Buses Company (TBC) and National Trailers Company (NTC).

The paper is based on semi-structured interviews, an analysis of documents and observations. It draws on New Institutional Sociology (NIS) perspective (DiMaggio and Powell’s 1983) as theoretical framework to provide explanations regarding how the MACS in the two companies were shaped by various factors.

The main factors identified in shaping the operations of the MACS were the need to comply with the political pressures, the Libyan Government’s laws and regulations, the instructions imposed by the management committee in both companies, leading organizations’ pressures (ISO), customer satisfaction (coercive isomorphism), the influence of professional associations (normative isomorphism) and the need to imitate efficient organizations in order to be more legitimate and successful (mimetic isomorphism).

The findings of the study have implications for understanding the operations of MACS in developing countries. Future research could focus on alternative theoretical perspectives for the investigation of the process of change in MACS such as structuration theory, agency theory and actor-network theory.

The proposed theoretical framework provides insights into the process of change by focusing on the interplay between the institutional forces, market forces and intra – organizational power relationships to overcome the criticism of NIS that it downplays the role of market forces and intra – organizational power relations.

Ultra-high molecular weight polyethylene (UHMWPE) is adopted in water-lubricated bearings for its excellent performance. This paper aims to investigate the tribological properties of UHMWPE with a molecular weight of 10.2 million (g mol^‐1) under different molding temperatures.

The UHMWPE samples were prepared by mold pressing under constant pressure and different molding temperatures (140°C, 160°C, 180°C, 200°C, 220°C). The friction and wear tests in water were conducted at the RTEC tribo-tester.

The friction coefficient and wear loss decreased first and rose later with the increasing molding temperature. The minimums of the friction coefficient and wear loss were found at the molding temperatures of 200°C. At low melting temperatures, the UHMWPE molecular chains could not unwrap thoroughly, leading to greater abrasive wear. On the other hand, high melting temperatures will cause the UHMWPE molecular chains to break up and decompose. The optimal molding temperatures for UHMWPE were found to be 200°C.

Findings are of great significance for the design of water-lubricated UHMWPE bearings.

The purpose of this paper is to describe the quasi-experiment setting to test the formulated design support (developed in the author’s PhD research) within a design research methodology (DRM) framework. This support intends to help designers to consciously engage rural families within a development aid scenario and increase their self-reliance towards their built environment (housing).

This paper elaborates on the setting in which the design support was tested within a quasi-experiment. The literature section describes the challenges in design research and why the DRM is suitable for this type of empirical research.

Findings of the paper include a workable setting to organise and evaluate the impact of a design support within a DRM framework on a vulnerable rural community.

The main limitation of the research lies in the study population. Due to financial and time constraints, only four teams could participate in the experiment conducted in rural Kenya.

Further research will need to prove that the support works in comparable situations on the African continent.

The quasi-experiment setting within a DRM framework could benefit researchers in comparable empirical investigations.

Although additive manufacturing (AM; 3D printing/3DP) is presently in its infancy, once it becomes economically viable for mass production, it would revolutionize the operation and supply chain network of traditional businesses and manufacturing industries. To this end, approaches for ensuring a smooth transition of the economy, businesses, manufacturing centers and related services are being investigated. This review paper assesses the existing literature on the impact of AM on the maritime transportation sector.

This paper provides a systematic literature review through three methodological phases: (1) a comprehensive review of the number of English language literature studies published on the topics of AM or 3DP (1970–2021); (2) a bibliometric analysis of selected keyword combinations and (3) a detailed review on the impact of AM on different sectors.

The key findings are that existing studies do not attempt to forecast shipping volume and ton-miles that can be affected by the mainstreaming of the technology. Additionally, existing literature that focuses on the impact of the technology on different shipping categories is limited to studies on container ships.

The review identifies some potential areas of research that since maritime transportation will be affected by mainstreaming AM, it will have economic, social and environmental impacts on global trade that require future assessment.

This paper aims to discuss flow pattern transition (FPT) as an important factor in multiple-phase flow measurements. Several methods have been proposed to control FPT, but those methods fail to address the many issues in complex flow conditions that can affect flow patterns.

In this paper, a non-intrusive sensor instrumentation is applied to extract measurable data under different flow conditions. Using these data, a simple theoretical–mathematical method along with an orthogonal design is applied to FPT optimization. Orthogonal experiments are designed and carried out according to theoretical guidelines. Three selected process parameters – phase fraction, gas pressure in the initial independent process and liquid speed – are optimized for FPT results to produce a minimum FPT time.

The following results are obtained: the phase fraction in the initial independent process can lead to significant reductions in FPT time, gas pressure plays an important role and liquid speed has no apparent effect on FPT results. Under optimized conditions, FPT time can be shortened to 0.3-0.6 times by controlling the above three parameters compared with normal conditions.

The proposed method is simple, rapid and efficient for evaluating an FPT process and lays the foundation for further FPT applications.

The purpose of this study is to develop a reconstruction and measurement system for data analysis using ultrasonic transmission tomography. The problem of reconstruction from the projection is encountered in practical implementation, which consists in reconstructing an image that is an estimation of an unknown object from a finite set of projection data. Reconstructive algorithms used in transmission tomography are based on linear mathematical models, which makes it necessary to process non-linear data into estimates for a finite number of projections. The application of transformation methods requires building a mathematical model in which the projection data forming the known and unknown quantities are functions with arguments from a continuous set of real numbers, determining the function describing the unknown quantities sought in the form of inverse relation and adapting it to operate on discrete and noisy data. This was done by designing a tomographic device and proprietary algorithms capable of reconstructing two-dimensional images regardless of the size, shape, location or number of inclusions hidden in the examined object.

The application consists of a device and measuring sensors, as well as proprietary algorithms for image reconstruction. Ultrasonic transmission tomography makes it possible to analyse processes occurring in an object without interfering with the examined object. The proposed solution uses algorithms based on ray integration, the Fermat principle and deterministic methods. Two applications were developed, one based on C and implemented on the embedded device, while the other application was made in Matlab.

Research shows that ultrasonic transmission tomography provides an effective analysis of tested objects in closed tanks.

In the presented technique, the use of ultrasonic absorption wave has been limited. Nevertheless, the effectiveness of such a solution has been confirmed.

The presented solution can be used for research and monitoring of technological processes.

Author’s tomographic system consisting of a measuring system and image reconstruction algorithms.

This paper aims to present a vision-based method for determination of the position of a fixed-wing aircraft that is approaching a runway.

The method determines the location of an aircraft based on positions of precision approach path indicator lights and approach light system with sequenced flashing lights in the image captured by an on-board camera.

As the relation of the lighting systems to the touchdown area on the considered runway is known in advance, the detected lights, seen as glowing lines or highlighted areas, in the image can be mapped onto the real-world coordinates and then used to estimate the position of the aircraft. Furthermore, the colours of lights are detected and can be used as auxiliary information.

The presented method can be considered as a potential source of flight data for autonomous approach and for augmentation of manual approach.

In this paper, a feasibility study of this concept is presented and primarily validated.

The purpose of this paper is to provide academics, practitioners, and students with an opportunity to understand the dynamics of growing an entrepreneurial business in the emerging markets of the high‐tech industry in Poland. Limited academic studies have analyzed the evolution of high‐tech entrepreneurial businesses in the emerging markets of Central and Eastern Europe (CEE).

A case study format is used to illustrate some of the operational problems related to developing a business in the high‐tech sector.

The case study offers some implications for academics and practitioners. For academics, the paper points out two areas of possible investigation. For practitioners, it highlights five problem areas specific to developing start‐up high‐tech businesses in the CEE region, with the most challenging problem being access to finance.

The case study provides at least three benefits for academics and practitioners focusing on the CEE region. First, while academic literature highlights the importance of newly developed entrepreneurial firms in transforming centrally planned economies of the CEE region, there has been limited attention given to understanding the dynamics of developing early‐stage companies in the high‐tech sector. The case study fills an important gap in academic literature in this respect. Second, it demonstrates company‐specific operational problems as well as external market challenges. Other businesses in the sector operating in the CEE region can benefit from this experience and address similar problems well in advance. Third, the paper describes the dynamics of business failure. Such descriptions are unique in academic literature.