The Development of an Experimental Research Plan Based on Local Strain-Life Method for an Air Handling Unit Subjected to Seismic Loads

2014 ◽  
Vol 224 ◽  
pp. 226-231
Author(s):  
Michał Burak ◽  
Dariusz Skibicki ◽  
Michał Stopel

This paper presents procedures to be used for development of an experiment plan which is supposed to provide the tested structure with operating conditions most similar to those in real life. The research object is an air handling unit subjected to random loading such as earthquakes.

2019 ◽  
pp. 116-122
Author(s):  
V. V. Stepanov ◽  
A. D. Kashtanov ◽  
S. U. Shchutsky ◽  
A. N. Agrinsky ◽  
N. I. Simonov

We consider the results of studies on the choice of material of the lower radial bearing of the pump, designed to circulate the coolant lead – bismuth. The circulation of the liquid coolant is provided by a vertical axial pump having a “long” shaft. In this design it is necessary to provide for the lower bearing the lubrication carried out with lead – bismuth coolant. Having analyzed the operating conditions of the axial pump, we decided to carry out the lower bearing in accordance with the scheme of a hydrodynamic sliding bearing. The materials of friction pairs in such a bearing must withstand the stresses arising from the operation of the pump, as well as the aggressive conditions of the coolant. Non-metallic materials – ceramics and carbon-based composite materials – were selected basing on the study of literature data for experimental research on the corrosion and heat resistance in the lead-bismuth environment. 


Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 412
Author(s):  
Mirosław K. Szukiewicz ◽  
Krzysztof Kaczmarski

A dynamic model of the hydrogenation of benzene to cyclohexane reaction in a real-life industrial reactor is elaborated. Transformations of the model leading to satisfactory results are presented and discussed. Operating conditions accepted in the simulations are identical to those observed in the chemical plant. Under those conditions, some components of the reaction mixture vanish, and the diffusion coefficients of the components vary along the reactor (they are strongly concentration-dependent). We came up with a final reactor model predicting with reasonable accuracy the reaction mixture’s outlet composition and temperature profile throughout the process. Additionally, the model enables the anticipation of catalyst activity and the remaining deactivated catalyst lifetime. Conclusions concerning reactor operation conditions resulting from the simulations are presented as well. Since the model provides deep insight into the process of simulating, it allows us to make knowledge-based decisions. It should be pointed out that improvements in the process run, related to operating conditions, or catalyst application, or both on account of the high scale of the process and its expected growth, will remarkably influence both the profits and environmental protection.


Author(s):  
Sasadhar Bera ◽  
Indrajit Mukherjee

A common problem generally encountered during manufacturing process improvement involves simultaneous optimization of multiple ‘quality characteristics’ or so-called ‘responses’ and determining the best process operating conditions. Such a problem is also referred to as ‘multiple response optimization (MRO) problem’. The presence of interaction between the responses calls for trade-off solution. The term ‘trade-off’ is an explicit compromised solution considering the bias and variability of the responses around the specified targets. The global exact solution in such types of nonlinear optimization problems is usually unknown, and various trade-off solution approaches (based on process response surface (RS) models or without using process RS models) had been proposed by researchers over the years. Considering the prevalent and preferred solution approaches, the scope of this paper is limited to RS-based solution approaches and similar closely related solution framework for MRO problems. This paper contributes by providing a detailed step-by-step RS-based MRO solution framework. The applicability and steps of the solution framework are also illustrated using a real life in-house pin-on-disc design of experiment study. A critical review on solution approaches with details on inherent characteristic features, assumptions, limitations, application potential in manufacturing and selection norms (indicative of the application potential) of suggested techniques/methods to be adopted for implementation of framework is also provided. To instigate research in this field, scopes for future work are also highlighted at the end.


2013 ◽  
Vol 12 (3) ◽  
pp. 035-038
Author(s):  
Wacław Bieda ◽  
Jan Radoń ◽  
Grzegorz Nawalany

The paper presents the results of two-year studies conducted in real operating conditions of a non-insulated and unheated barn for 120 cows. As a result, it was possible to determine temperature fields in the ground beneath the floor and around the building, as well as to define heat flux directions. It was concluded that there is no analogy between temperature fields and heat flux directions with the heated buildings. In colder periods of the year, the heat accumulated in the ground is emitted to the inside of the building; in the summer, the ground absorbs the excess of heat from the building. The final conclusion was that the foundations should be insulated vertically.


2018 ◽  
Vol 12 (3) ◽  
pp. 221-226 ◽  
Author(s):  
Andrzej Borawski

Abstract Among the many elements of a modern vehicle, the braking system is definitely among the most important ones. Health, and, frequently, life, may rest upon the design and reliability of brakes. The most common friction pair used in passenger cars today is a disc which rotates with the road wheel and a cooperating pair of brake pads. The composite material of the pad results in changing tribological properties as the pad wears, which was demonstrated in experimental studies. The change is also facilitated by the harsh operating conditions of brakes (high and rapid temperature changes, water, etc.). This paper looks into how changing tribology reflects on the heating process of disc and pads during braking. And so a simulation study was conducted, as this method makes it possible to measure temperature in any given point and at any time, which is either impossible or extremely difficult in real life conditions. Finite element method analyses were performed for emergency braking events at various initial speeds of the vehicle reflecting the current road speed limits.


Author(s):  
Vladimir Bilik

A Rieke diagram [1] is a magnetron characteristic that visualizes the dependence of the generated frequency fg and the net delivered power PL on the load reflection coefficient GR. GR is defined in a specific magnetron-to-waveguide coupling structure called the standard or reference launcher (Fig. 1). The diagram is plotted as a family of isolines of constant fg and of constant PL in the polar diagram of GR. Rieke diagrams are essential in the design of applications without isolators, such as domestic or professional microwave ovens. Constructing Rieke diagrams is tedious, time-consuming and equipment-demanding [2], [3], preventing systematic studies of their dependence on operating conditions, such as anode voltage and its ripple, filament current, mounting repeatability, etc. We have devised a procedure, centering around a high-power automatic impedance matching device (autotuner), which enables fully automatic measurement and plotting of the stated dependences. A block diagram of the setup is shown in Fig. 1. The autotuner, when terminated in a match (waterload), can accomplish a task inverse to impedance matching: realizing any desired reflection coefficient GR. The measurement consists of stepping through a grid of n suitably chosen reflection coefficients GR = xR + jyR, covering a desired area of the polar diagram. Each GR is measured accurately by the autotuner, along with the corresponding fg and PL. Thus, raw data for constructing a Rieke diagram are obtained, the data consisting of a collection of n points {GR, fg, PL}i, i = 1…n, with GR, in general, irregularly scattered in the complex plane. A dedicated MATLAB routine then reads the data, sorts them out to create tabulated functions fg = f(xR, yR), PL = f(xR, yR), approximates these by a 2D spline, and uses the splines to plot smoothed isocontours for chosen constant values of fg and PL, completing thus the desired Rieke diagram construction. We will present details of this procedure as well as real-life examples. Fig. 1. Rieke diagram measurement setup. References Meredith, R. J., Engineers' Handbook of Industrial Microwave Heating, London: The IEE, 1998, 250–270. Takahashi, H., I. Namba, K. Akiyama, J. Microwave Power, 1979, 14, 261–267.Yixue, W., Z. Zhaotang, Proc. ICMMT'98, 1998, 795–798.


EL LE ◽  
2018 ◽  
Author(s):  
Marcella Menegale

One of the aims of language learning is that learners can apply outside the classroom what they learn at school and, vice versa, can use in classroom what comes from their experience in ‘real’ life, that is, outside school walls. However, as nearly a century of experimental research on the field has proved, knowledge transfer does not occur spontaneously, on the contrary, this capacity seems to be particularly complicated and difficult to encourage. It is therefore crucial to help learners gain awareness and make use of existing language learning opportunities as well as the learning strategies they can employ so to increase their capacity to make connections. Among the different tools that can be used to enhance both language competence and metacognitive awareness, logbook is considered one of the most handy and purposeful. This paper will try to explain what a logbook is and how it can be used with students with the intention to promote their language learning both in and out of the classroom.


2015 ◽  
Vol 237 ◽  
pp. 148-153 ◽  
Author(s):  
Stanisław Kozioł ◽  
Szymon Zacharski

The increasing prices of energy and the drive to reduce the emission of greenhouse gases into the atmosphere observed in the recent years have contributed to the intensive development of research on how to reduce the energy consumption of buildings. The confirmations of the current trends are the formal and legal regulations of the European Union that require the buildings to be passive and “zero-energy” in the near future. The introduction of new elements helping one to save energy in the structure of a building requires their formal verification and the confirmation of their safety, effectiveness, and parameters crucial from the point of their application in residential buildings and offices. The authors present an original prototype of an innovative device and a methodology of conducting studies on air-handling units with heat recuperation used in passive and energy-saving buildings. They also discuss the structure and the modus operandi of the system that reconstructs the actual operating conditions of a tested object. The system was used for tests on the tightness of several air-handling units, which also aimed at the verification of their thermal efficiency and the effectiveness of the recuperation of humidity. Air-handling unit tests came from different manufacturers, and they all had the function of heat recuperation. The authors present the results of their investigations that enabled the assessment of the safety of the objects tested, and they also facilitated the comparison of their performance parameters deciding on the energy effect. The tests also formed the foundation for the verification of the developed research system.


Author(s):  
D. M. Bardot ◽  
A. F. Emery

The motivation for this work is the need to analyze the behavior of an engineering system subjected to the hostile environment of a fire. The specific goal is to estimate the survivability of a component potted in insulating foam. The foam undergoes an endothermic reaction and through this heat sink protects the component. Because the operating conditions are stochastic and because the properties of the foam can only be estimated, the usual deterministic analysis cannot be used. Instead, Bayesian inference is used to estimate the critical foam parameters and the operating conditions are described in terms of probabilities. The survivability is then expressed in terms of a probability distribution. Because the computations are very computationally expensive, recourse was made by expressing the computed results as a response surface defined in terms of a Gaussian process.


Author(s):  
Charles Fernandez ◽  
Arun Kr. Dev ◽  
Rose Norman ◽  
Wai Lok Woo ◽  
Shashi Bhushan Kumar

Abstract The Dynamic Positioning (DP) System of a vessel involves complex interactions between a large number of sub-systems. Each sub-system plays a unique role in the continuous overall DP function for safe and reliable operation of the vessel. Rating the significance or assigning weightings to the DP sub-systems in different operating conditions is a complex task that requires input from many stakeholders. The weighting assignment is a critical step in determining the reliability of the DP system during complex marine and offshore operations. Thus, an accurate weighting assignment is crucial as it, in turn, influences the decision-making of the operator concerning the DP system functionality execution. Often DP operators prefer to rely on intuition in assigning the weightings. However, it introduces an inherent uncertainty and level of inconsistency in the decision making. The systematic assignment of weightings requires a clear definition of criteria and objectives and data collection with the DP system operating continuously in different environmental conditions. The sub-systems of the overall DP system are characterized by multi-attributes resulting in a high number of comparisons thereby making weighting distribution complicated. If the weighting distribution was performed by simplifying the attributes, making the decision by excluding part of them or compromising the cognitive efforts, then this could lead to inaccurate decision making. Multi-Criteria Decision Making (MCDM) methods have evolved over several decades and have been used in various applications within the Maritime and Oil and Gas industries. DP, being a complex system, naturally lends itself to the implementation of MCDM techniques to assign weight distribution among its sub-systems. In this paper, the Analytic Hierarchy Process (AHP) methodology is used for weight assignment among the DP sub-systems. An AHP model is effective in obtaining the domain knowledge from numerous experts and representing knowledge-guided indexing. The approach involved examination of several criteria in terms of both quantitative and qualitative variables. A state-of-the-art advisory decision-making tool, Dynamic Positioning Reliability Index (DP-RI), is used to validate the results from AHP. The weighting assignments from AHP are close to the reality and verified using the tool through real-life scenarios.


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