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The rate of copper dissolution in presence of phosphoric acid‐formaldehyde mixtures were studied by measuring the limiting current which represents the rate of electropolishing. It is found that the rate of dissolution is decreased by increasing H₃PO₄ concentration, electrode height and mole fraction of formaldehyde. It is found that the decrease in the rate of dissolution ranges from 24 per cent to 63.88 per cent depends on the mole fraction of formaldehyde. The thermodynamic parameter ΔH* ΔG* ΔS* was calculated.

This paper sets out to highlight several aspects of a project, aimed at developing an advanced thermal comfort guideline, based on the adaptive thermal comfort theory.

The paper introduces the new Dutch adaptive guideline for thermal comfort. The initial method exceeding hours (TO) is discussed, as well as the more recent method of weighted temperature exceeding hours (GTO). An evaluation of the practical and theoretical shortcomings of the TO and GTO methods is discussed, as well as the rationale behind the adaptive ATG guideline. Furthermore, the results are presented of computer simulations in which the predictions of the different methods are compared. Productivity effects of the new guideline are also discussed, as well as the implications for cooling system sizing and energy efficiency.

The adaptive temperature limits (ATG) guidelines appears to be a more reliable method for the assessment of thermal comfort, in particular for passive, free‐running buildings, compared with the PMV‐based method of weighted temperature exceeding hours (GTO). Furthermore, the ATG method allows for a wider temperature range for Alpha type buildings and gives more opportunity for the development of sustainable, naturally ventilated buildings and limiting cooling energy.

Although the new ATG method shows promising results, more research is needed. The exact distinction between Alpha and Beta is still subject to further research, as well as the question whether a certain amount of exceeding hours of the ATG limits should be accepted.

The ATG method is being used in The Netherlands for the assessment of thermal comfort in the design stage as well as in the assessment of the performance of buildings in use.

This paper discusses the first application of the adaptive thermal comfort theory in a practical guideline.

The purpose of this study is to address one-dimensional, unsteady heat conduction in a large plane wall exchanging heat convection with a nearby fluid under “small time” conditions.

The Transversal Method of Lines (TMOL) was used to reformulate the unsteady, one-dimensional heat conduction equation in the space coordinate and time into a transformed “quasi-steady”, one-dimensional heat conduction equation in the space coordinate housing the time as an embedded parameter. The resulting ordinary differential equation of second order with heat convection boundary conditions is solved analytically with the method of undetermined coefficients.

Semi-analytical TMOL dimensionless temperature profiles of compact form with/without regressed terms are obtained for the whole spectrum of Biot number (0 < Bi < ∞) in the “small time” sub-domain. In addition, a new “large time” sub-domain is redefined, that is, setting a smaller critical dimensionless time or critical Fourier number τ_cr = 0.18.

The computed dimensionless center, surface and mean temperature profiles in the large plane wall accounting for all Biot number (0 < Bi < ∞) in the “small time” sub-domain τ < τ_cr = 0.18 exhibit excellent quality while carrying reasonable relative errors for engineering applications. The exemplary level of accuracy indicates that the traditional evaluation of the center, surface and mean temperatures with the standard infinite series retaining a large number of terms is no longer necessary.

Fundamentally, it is advantageous to operate an aeroengine's thermodynamic cycle at as high a turbine entry temperature as practical for the current metallurgical limits of the turbine blades in order to achieve peak cycle efficiency and thus lower specific fuel consumption. However, achieving the highest possible turbine entry temperature requires accurate knowledge of the turbine blade temperatures for control purposes to prolong component life as frequent excursions beyond the design limits of the blades can severely reduce their service life. The optical pyrometry technique represents the best method for providing this crucial temperature data needed for blade condition‐based monitoring. This paper presents the general operating principles, system aspects and design considerations for the application of the optical pyrometer instrument for inflight service use on gas turbine aeroengines.

To develop and find the effect of combination of four cycle design variables that minimizes the specific fuel consumption (sfc) of a turbofan engine.

After choosing the four variables, namely bypass ratio (B), fan pressure ratio, overall pressure ratio, and turbine inlet temperature (T₀₄), first the sfc was minimized without a minimum thrust constraint. Then, a minimum specific thrust constraint was introduced.

The unconstrained‐specific thrust is a two‐dimensional optimization problem, whereas the specific thrust constrained problem was found to be a three‐dimensional one.

The variables B and ï are limiting factors to further improvement, as set by their maximum practical values, whereas the other two variables are to be optimized.

A very useful work, in which numerical optimization program was developed, for a turbofan cycle and could be extended to other cycles.

This paper offers a great help to those intending to optimize certain cycles with a number of variables.

This study aims to review the recent advancements in high entropy alloys (HEAs) called high entropy materials, including high entropy superalloys which are current potential alternatives to nickel superalloys for gas turbine applications. Understandings of the laser surface modification techniques of the HEA are discussed whilst future recommendations and remedies to manufacturing challenges via laser are outlined.

Materials used for high-pressure gas turbine engine applications must be able to withstand severe environmentally induced degradation, mechanical, thermal loads and general extreme conditions caused by hot corrosive gases, high-temperature oxidation and stress. Over the years, Nickel-based superalloys with elevated temperature rupture and creep resistance, excellent lifetime expectancy and solution strengthening L12 and γ´ precipitate used for turbine engine applications. However, the superalloy’s density, low creep strength, poor thermal conductivity, difficulty in machining and low fatigue resistance demands the innovation of new advanced materials.

HEAs is one of the most frequently investigated advanced materials, attributed to their configurational complexity and properties reported to exceed conventional materials. Thus, owing to their characteristic feature of the high entropy effect, several other materials have emerged to become potential solutions for several functional and structural applications in the aerospace industry. In a previous study, research contributions show that defects are associated with conventional manufacturing processes of HEAs; therefore, this study investigates new advances in the laser-based manufacturing and surface modification techniques of HEA.

The AlxCoCrCuFeNi HEA system, particularly the Al0.5CoCrCuFeNi HEA has been extensively studied, attributed to its mechanical and physical properties exceeding that of pure metals for aerospace turbine engine applications and the advances in the fabrication and surface modification processes of the alloy was outlined to show the latest developments focusing only on laser-based manufacturing processing due to its many advantages.

It is evident that high entropy materials are a potential innovative alternative to conventional superalloys for turbine engine applications via laser additive manufacturing.

The subject of this paper is high temperature corrosion in chlorine and hydrogen chloride gaseous environments. The discussion will be limited to metals and alloys such as iron and carbon steel, iron‐chromium alloys and stainless steels, nickel and nickel alloys which are of interest in the petroleum industry.

The purpose of this paper is to report the first of four planned fire experiments on the 9.1 × 6.1 m steel composite floor assembly as part of the two-story steel framed building constructed at the National Fire Research Laboratory.

The fire experiment was aimed to quantify the fire resistance and behavior of full-scale steel–concrete composite floor systems commonly built in the USA. The test floor assembly, designed and constructed for the 2-h fire resistance rating, was tested to failure under a natural gas fueled compartment fire and simultaneously applied mechanical loads.

Although the protected steel beams and girders achieved matching or superior performance compared to the prescribed limits of temperatures and displacements used in standard fire testing, the composite slab developed a central breach approximately at a half of the specified rating period. A minimum area of the shrinkage reinforcement (60 mm²/m) currently permitted in the US construction practice may be insufficient to maintain structural integrity of a full-scale composite floor system under the 2-h standard fire exposure.

This work was the first-of-kind fire experiment conducted in the USA to study the full system-level structural performance of a composite floor system subjected to compartment fire using natural gas as fuel to mimic a standard fire environment.

AT the outset we ought to say that we could probably have done more justice to a paper on the “High Output cf Aero‐Engines.”

THE COMPLEXITY of modern pressurisation and air conditioning systems for jet aircraft have led increasingly to the practice of selecting a single contractor to design and integrate all of the components into a compatible system tailored to the mission requirements of the aircraft.