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Purpose – The aim of this note is to explain what Hayek meant when in The Sensory Order he claimed that Mach was one of his fundamental readings in psychology while he was writing The Sensory Order.

Methodology/approach – A historical approach to show the different role Mach played in Hayek and Neurath/Carnap.

Findings•A parallelism between Mach–Kant and Hayek–Mach in psychology.•Hayek's rejection of Mach's final philosophical approach as well as his aversion against the Vienna Circle's positivism as forms of metaphysics, based on an awkward definition of isomorphism.

Research limitations/implications•The human sciences cannot be reduced to the natural sciences.•Any form of knowledge is knowledge of “how” rather than of “what”.

Originality/value of the paper•To show Mach's role in Hayek's psychology.•To consider The Sensory Order as a relevant part of Hayek's struggle against reductionism in psychology.

THE problem of providing engines suitable for high Mach number aircraft is a fascinating study which at the moment has only been taken to the stage where many solutions look feasible, thus the choice of engines for the different roles for which high Mach number aircraft may be used is still fairly wide open.

The purpose of this study is to experimentally investigate the trends in shock wave Mach number that were observed when different diaphragm material combinations were used in the small-scale shock tube.

A small-scale shock tube was designed and fabricated having a maximum Mach number production capacity to be 1.5 (theoretically). Two microphones attached in the driven section were used to calculate the shock wave Mach number. Preliminary tests were conducted on several materials to obtain the respective bursting pressures to decide the final set of materials along with the layered combinations.

According to the results obtained, 95 GSM tracing paper was seen to be the strongest reinforcing material, followed by 75 GSM royal executive bond paper and regular 70 GSM paper for aluminium foil diaphragms. The quadrupled layered diaphragms revealed a variation in shock Mach number based on the position of the reinforcing material. In quintuple layered combinations, the accuracy of obtaining a specific Mach number was seen to be increasing. Optimization of the combinations based on the production of the shock wave Mach number was carried out.

The shock tube was designed taking maximum incident shock Mach number as 1.5, the experiments conducted were found to achieve a maximum Mach number of 1.437. Thus, an extension to further experiments was avoided considering the factor of safety.

The paper presents a detailed study on the effect of change in the material and its position in the layered diaphragm combinations, which could lead to variation in Mach numbers that are produced. This could be used to obtain a specific Mach number for a required study accurately, with a low-cost setup.

The Method of Characteristics for two‐dimensional supersonic flow is developed from an elementary physical approach. Since the report is intended for use by those on supersonic research who have not advanced mathematical knowledge, the initial parts of the theory are given in greater detail than in many other treatments. In addition numerical examples are given to illustrate points more clearly. The relationship of the method to the Prandtl‐Meyer expansion of a supersonic stream round a convex corner is stressed and the theory of the expansion is developed from first priciples in the Appendix. The application of the method of characterisics to the design of supersonic nozzles is not fully discussed, but the constructional drawing of a typical nozzle is given, together with a photograph of characteristics obtained experimentally.

This study aims to present the numerical study on supersonic jet mixing characteristics of the co-flow jet by varying lip thickness (LT). The LT chosen for the study is 2 mm, 7.75 mm and 15 mm.

The primary nozzle is designed for delivering Mach 2.0 jet, whereas the secondary nozzle is designed for delivering Mach 1.6 jet. The Nozzle pressure ratio chosen for the study is 3 and 5. To study the mixing characteristics of the co-flow jet, total pressure and Mach number measurements were taken along and normal to the jet axis. To validate the numerical results, the numerical total pressure values were also compared with the experimental result and it is proven to have a good agreement.

The results exhibit that, the 2 mm lip is shear dominant. The 7.75 mm and 15 mm lip is wake dominant. The jet interaction along the jet axis was also studied using the contours of total pressure, Mach number, turbulent kinetic energy and density gradient. The radial Mach number contours at the various axial location of the jet was also studied.

The effect of varying LT in exhaust nozzle plays a vital role in supersonic turbofan aircraft.

Supersonic co-flowing jet mixing effectiveness by varying the LT between the primary supersonic nozzle and the secondary supersonic nozzle has not been analyzed in the past.

This study aims to investigate effects of sonic jet injection into supersonic cross-flow (JISC) numerically in different dynamic pressure ratio values and free stream Mach numbers.

Large Eddy simulation (LES) with dynamic Smagorinsky model is used as the turbulence approach. The numerical results are compared with the experimental data, and the comparison shows acceptable validation.

According to the results, the dynamic pressure ratio has critical effects on the zone related to barrel shock. Despite free stream Mach number, increasing dynamic pressure ratio leads to expansion of barrel shock zone. Consequently, expanded barrel shock zone would bring about more obstruction effect. In addition, the height of counter-rotating vortex pair increases, and the high-pressure area before jet and low-pressure area after jet will rise. The results show that the position of barrel shock is deviated by increasing free stream Mach number, and the Bow shock zone becomes stronger and close to barrel shock. Moreover, high pressure zone, which is located before the jet, decreases by high free stream Mach number.

In this study, LES with a dynamic Smagorinsky model is used as the turbulence approach. Effects of sonic JISC are investigated numerically in different dynamic pressure ratio values and free stream Mach numbers.

As summary, the following are the contribution of this paper in the field of JISC subjects: several case studies of jet condition have been performed. In all the cases, the flow at the nozzle exit is sonic, and the free stream static pressure is constant. To generate proper grid, a cut cell method is used for domain modelling. Boundary condition effect on the wall pressure distribution around the jet and velocity profiles, especially S shape profiles, is investigated. The results show that the relation between representing the location of Mach disk centre and at transonic regime is a function of second-order polynomial, whereas at supersonic regime, the relationship is modelled as a first-order polynomial. In addition, the numerical results are compared with the experimental data demonstrating acceptable validation.

Machiavellian, narcissistic, and psychopathic traits are often viewed as negative or undesirable personality traits. However, recent research demonstrates that individuals with these traits possess qualities that may be personally beneficial within the business contexts. In this chapter, we conceptualize a balanced perspective of these traits throughout the entrepreneurial process (opportunity recognition, opportunity evaluation, and opportunity exploitation) and discuss human resources management strategies that can be employed to enhance the benefits, or minimize the challenges, associated with Machiavellian, narcissistic, and psychopathic traits. Specifically, we propose that Machiavellian qualities are most beneficial in the evaluation stage of entrepreneurship, and Machiavellian, narcissistic, and psychopathic qualities are beneficial in the exploitation stage of entrepreneurship.

This study aims to reveal the potential dark side of servant leadership by exploring its differential impact on followers with varying degrees of Machiavellianism and to uncover the role of leader negative feedback as an intervention mechanism in attenuating this negative impact.

A three-wave survey with one-month intervals was conducted with 344 participants from different industries.

The results suggest that servant leadership triggered psychological entitlement among followers with high Machiavellianism, leading to organizational and interpersonal deviance, but only when negative feedback from the leader was weak.

When leaders implement servant leadership, they should beware of breeding psychological entitlement among highly Machiavellian followers, as this can activate their deviant behavior, and should make full use of negative feedback as an intervention mechanism.

This study is one of the first to use the self-evaluation perspective to examine the negative impact of servant leadership on follower behavior via attitude and to explore boundary conditions to overcome this effect.

The purpose of this paper is to develop a new approach for rapid computation of subsonic and low-transonic rotary derivatives with the available steady solutions obtained by Euler computational fluid dynamics (CFD) codes.

The approach is achieved by the perturbation on the steady-state pressure of Euler CFD codes. The resulting perturbation relation is established at a reference Mach number between rotary derivatives and normal velocity on surface due to angular velocity. The solution of the reference Mach number is generated technically by Prandtl–Glauert compressibility correction based on any Mach number of interest under the assumption of simple strip theory. Rotary derivatives of any Mach number of interest are then inversely predicted by the Prandtl–Glauert rule based on the reference Mach number aforementioned.

The resulting method has been verified for three typical different cases of the Basic Finner Reference Projectile, the Standard Dynamics Model Aircraft and the Orion Crew Module. In comparison with the original perturbation method, the performance at subsonic and low-transonic Mach numbers has significantly improved with satisfactory accuracy for most design efforts.

The approach presented is verified to be an efficient way for computation of subsonic and low-transonic rotary derivatives, which are performed almost at the same time as an accounting solution of steady Euler equations.

This paper aims to reveal the influence of selected geometric parameters on the aerodynamic performance of circular variable aero engine inlets in transonic and supersonic civil aviation.

The trade-off in inlet design and aerodynamic evaluation parameters is presented. The approach to investigate the dependencies between the aerodynamic and geometric parameters at different flight conditions by means of a parametric design study is introduced.

The dependencies of inlet drag and efficiency from geometric parameters at flight speeds of Mach 0.95 up to Mach 1.6 are identified. Although entailing additional weight, the inlet length represents the parameter with the highest potential for drag reduction by up to 50% in the selected design space. Ideal geometries for variable pitot inlets are determined. After considering weight, their potential range benefit nearly disappears for subsonic applications, but remains above 20% for supersonic flight at Mach 1.6.

Hence, the technology of circular variable pitot inlets for supersonic transport aircraft could be a way to achieve the ambitious ecological, safety and economic goals for future civil aviation.