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In this study, we introduce and discuss a concept of fuzzy plug‐ins and investigate their role in system modeling. Fuzzy plug‐ins are rule‐based constructs augmenting a given global model (arising in the form of some regression relationship, neural network, etc.) in the sense that they compensate for the mapping errors produced by the global model. The proposed design method develops around information granules of error defined in the output space and the induced fuzzy relations expressed in the space of input variables. The construction of the linguistic granules is carried out with the aid of context‐based fuzzy clustering – a generalized version of the well‐known FCM algorithm that is well‐suited to the design of fuzzy sets and relations being used as a blueprint of the plug‐ins. An overall modeling architecture combining the global model with its plug‐ins is discussed in detail and a complete design procedure is provided. Finally, some illustrative numerical examples are shown as well.

The purpose of this paper is to present the materials and process considerations and solutions that enable the safe use of plugging pastes in high density interconnection (HDI) printed circuit boards (PCBs) designed to operate at higher temperatures.

The paper introduces the concept of microvia plugging and the issues that are important in influencing HDI PCB reliability. Plugging pastes and their properties are discussed along with the various plugging processes that can be used. The advantages and disadvantages of each type of process are compared and contrasted.

The creation of via holes and the filling of these interconnection holes or buried vias and their subsequent copper plating is one of the key processes in HDI technology. In future, the importance of plugging will increase, particularly on account of the growing demand for copper plating and dimensional stability.

The paper highlights the importance of making the correct selection of materials and processing methodologies and details the implications of these choices.

The paper describes the different approaches that can be used for filling microvias and details the issues, advantages and disadvantages of the various approaches. The paper particularly focuses on the special demands on plugging pastes used in higher temperature range applications.

An advanced heat transfer model for both unlooped and looped Pulsating Heat Pipes (PHPs) with multiple liquid slugs and vapor plugs has been developed. The thin film evaporation and condensation models have been incorporated with the model to predict the behavior of vapor plugs and liquid slugs in the PHP. The results show that heat transfer in both looped and unlooped PHPs is due mainly to the exchange of sensible heat. Higher surface tension results in a slight increase in the total heat transfer. The diameter, heating wall temperature, and charging ratio have significant effects on the performance of the PHP. Total heat transfer significantly decreased with a decrease in the heating wall temperature. Increasing the diameter of the tube resulted in higher total heat transfer. The results also showed that the PHP could not operate for higher charge ratios.

SOME new types of K.L.G. spark plugs for piston aero engines have recently gained Air Registration Board approval and have been undergoing intensive field trials with several operators and engine manufacturers over the past year. These plugs are believed to be the first in the world to have iridium electrodes, instead of the conventional platinum alloy electrodes. The aim is to increase the life of spark plugs, which at present arc prone to premature failure under certain kinds of operating conditions.

As in the S.6's of 1929, the plugs fitted to the engines of this year's Schneider Trophy seaplanes were supplied by Lodge Plugs, Limited, of Rugby. Early readers of AIRCRAFT ENGINEERING will remember that a special description by Mr. Alec M. Lodge of the evolution of plugs capable of standing up to the work required of them in engines of high output was published in Vol. I, October, 1929, at page 274. The plug used this year was the Lodge X. 170 made in the firm's model factory at Rugby, the only factory in Europe devoted exclusively to the manufacture of sparking plugs. The exclusive patents and processes used in the making of the special Schneider Trophy plugs, are incorporated in the standard patterns for aircraft.

In a compression‐ignition engine of the type in which substantially the whole of the air charge is forced into a spherical offset combustion chamber F during the compression stroke, the fuel is discharged by an injector H in a compact stream which passes through the centre of the chamber and impinges on an uncooled plug G, which forms the lower portion of the combustion chamber, at a spot adjacent to a tapering passage G4 through which the air is forced tangentially into the chamber; the circumferential portions of the rotating air charge are thus brought progressively into contact with the fuel spray as it impinges on the plug so that the air and fuel are thoroughly mixed immediately before the charge reaches the inner end of the passage G4, and the tendency for unconsumed air to be driven out of the chamber is reduced. No fuel is injected directly into the end of the passage. The passage may be of circular cross section throughout, or it may change to a crescent or kidney shape towards its inner end, the area of the latter end being preferably three‐fifths that at the outer. Instead of the passage traversing the plug, it may be formed by a groove cut in the outer cylindrical surface of the plug, the direction of rotation of the charge thus being opposite to that obtaining in Fig. 1. The plug G is made of a heat‐resisting metal of low heat conductivity; it is fitted loosely in the mouth of a water‐cooled pocket so that it is surrounded by a heat insulating air‐space F1. A retaining ring G2 may be optionally provided, the off‐set of the plug ensuring sufficient overlap between the cylinder end and plug to retain the latter if the ring is omitted. In the modified construction shown in Fig. 3, the upper portion of the combustion chamber is provided with a liner K which is insulated from the water‐cooled pocket by an air gap; the liner is supported by an integral boss K1 which passes through a bore in the wall of the pocket and is secured by a ring K2. An electrically heated hot wire J is employed at starting. The injector socket passes through the water jacket chamber of the cylinder head to ensure adequate cooling. Specification 371,025 is referred to.

This paper aims to investigate the effect of plugging of holes on the static performance characteristics of a constant flow valve compensated hole‐entry hybrid journal bearing system operating with Newtonian and non‐Newtonian lubricants. The analysis considers the generalized Reynolds equation governing the flow of lubricant having variable viscosity in the clearance space and equation of flow of lubricant through constant flow valve restrictor. The non‐Newtonian lubricant is assumed to follow the power law. The performance characteristics are computed for the two values of power law index (n=1.0 and 0.566). The computed results indicate that the blockage of holes during operation will not be the likely causes for the imminent failure of a well‐designed non‐recessed hole‐entry hybrid journal bearing.

Finite element method has been used to solve generalized Reynolds equation governing the flow of lubricant having variable viscosity in the clearance space and equation of flow of lubricant through constant flow valve restrictor.

The computed results indicate that the blockage of holes during operation will not be the likely causes for the imminent failure of a well‐designed non‐recessed hole‐entry hybrid journal bearing. The bearing configuration with plugged holes provides sufficient fluid film thickness and low power requirement as less lubricant is required to be pumped in the bearing.

To the best of the author's knowledge, no study which considers the influence of plugging of holes on the static performance characteristics of a constant flow valve compensated hole‐entry hybrid journal bearing system operating with Newtonian and non‐Newtonian lubricant is yet available in the literature.

In the last decades, various building information modeling–life cycle assessment (BIM-LCA) integration approaches have been developed to assess the environmental impact of the built asset. However, there is a lack of consensus on the optimal BIM-LCA integration approach that provides the most accurate and efficient assessment outcomes. To compare and determine their accuracy and efficiency, this study aimed to investigate four typical BIM-LCA integration solutions, namely, conventional, parametric modeling, plug-in and industry foundation classes (IFC)-based integration.

The four integration approaches were developed and applied using the same building project. A quantitative technique for evaluating the accuracy and efficiency of BIM-LCA integration solutions was used. Four indicators for assessing the performance of BIM-LCA integration were (1) validity of LCA results, (2) accuracy of bill-of-quantity (BOQ) extraction, (3) time for developing life cycle inventories (i.e. developing time) and (4) time for calculating LCA results (i.e. calculation time).

The results show that the plug-in-based approach outperforms others in developing and calculation time, while the conventional one could derive the most accuracy in BOQ extraction and result validity. The parametric modeling approach outperforms the IFC-based method regarding BOQ extraction, developing time and calculation time. Despite this, the IFC-based approach produces LCA outcomes with approximately 1% error, proving its validity.

This paper forms one of the first studies that employ a quantitative and objective method to determine the performance of four typical BIM-LCA integration solutions and reveal the trade-offs between the accuracy and efficiency of the integration approaches. The findings provide practical references for LCA practitioners to select appropriate BIM-LCA integration approaches for evaluating the environmental impact of the built asset during the design phase.

THE ability to detect an impending failure in an aircraft engine mechanical power system, at an early stage, where expensive and possibly catastrophic system failures can be prevented, will provide enhanced aircraft safety by minimising the possibility of a serious engine failure, and the need for the pilot to shut down an engine during flight with all the attendant emergency ramifications that can arise. This will also improve the utilisation of the aircraft, by the scope to plan unscheduled engine removals to suit the aircraft downtime, and it will reduce the turnround time and costs to effect the necessary repairs; particularly if the skill of detection can also pinpoint the area of distress with accuracy.

AS early as 1894, in a paper on the subject of electrical radiation read at the Royal Institution, Sir Oliver Lodge explained the steps that it was necessary to take to screen electrical radiation. He pointed out that lor effective screening every part of the oscillating circuit must be completely enclosed in metal casing, and all the metal enclosures well connected together. He also explained that while small round holes in the casing did not matter, anything in the nature of a slot or chink, or the smallest “live” part of the circuit projecting through the casing, would allow the radiation to pass. The ignition system of a petrol engine generates an oscillating discharge, sending out electrical radiation, and to prevent this radiation interfering with a neighbouring radio receiver it is necessary to enclose the whole ignition circuit—magneto, cables and sparking plugs—in metal casing.