Papers by Keyword: Measurement

Abstract: Foundation of building on concrete piles is often used when it is necessary to carry the load into larger depth as by common foundation. Bearing capacity of piles or piled raft foundation is wide area to research. This paper deals with experimental load test of concrete pile and with their numerical modelling. Several types of foundation construction were tested and two kinds will be presented and compared in this paper - reinforced concrete foundation slab and raft foundation (made of reinforced concrete foundation slab supported by drilled reinforced concrete pilot). These types of foundation constructions were constructed as models, in a reduced scale, approx. 1:10. The size had to be adjusted due to limited capacity of the testing equipment and financial reasons. Except measuring of the foundation behaviour, there was also carried out measurement of the adjacent terrain.The aim of this paper is to compare the behaviour of rigid slab and the piled raft. The measurement results will be then compared with the results of numerical modelling.

Abstract: This article focuses on the estimation of a proper logarithmic damping decrement in industrial boilers when flue gases travel in the vertical direction. The structure for this type of facility is quite unified worldwide. The structural conception is rather simple, and the response to any static loading is predictable. Nevertheless, with regard to dynamics and damping, some specifics in the detailed solution make this system unique. For the purpose of this analysis, a Plexiglas scale model was prepared at a geometric scale of 1:20. A set of experimental modal analyses was performed on the model. Each test focused on the damping effect of specific details and compared it with the common structure without a damping effect. Finally, a site modal analysis was conducted on an actual boiler located in the CHP Torun Plant in Poland. The upper part of the structure was reinforced to have a horizontal deflection of 8 mm and was suddenly released. The resulting movement was recorded with an HD camera linked to a theodolite. Experimental results on the scale model of the actual structure confirmed that damping of this type of structure is significantly higher than that considered for common steel structures.

Abstract: Recently the usage of telecommunication networks in term of duration and frequency is increasing due to the invention of instant messenger applications such as WhatsApp, Blackberry Messenger (BBM), LINE, KakaoTalk, WeChat, and Telegram. Especially in Malaysia, the usage duration is the highest among the six countries in South East Asia-- Indonesia, Philippines, Singapore, Thailand, and Vietnam. It is important to know the factors influence the behaviour Malaysian toward the adoption of Instant messenger application in order to increase the usage frequency and duration of application in other countries. A study of Indrawati, Raman, Ariyanti, and Chew in 2015 proposed a new modified model toward the instant messenger applications adoption which has not been tested yet. This study intents to propose a measurement material to test the model. The material of measurement was derived from previous published researches. The method to test the measurement material was a pilot study with 30 Malaysians’ respondents. The result of this study reveals that the measurement material is valid and reliable, therefore it can be used for further study.

Abstract: In this paper, in order to realize friction torque measurement and assembly behavior analysis of arc structure servo mechanism (ASSM), a general measurement system applied, meanwhile structural characteristics and performance of the ASSM are analyzed. Based on the fundamental of electrical method, the system is built up by the principle of vertical structure in line. So the system can applied to all kinds of ASSM by replacing the U-shape frame which suits to the target servos. The experiment is carried out on a certain type, the mean value of dynamic friction torque is about 1.00Nm, and the variance of measured data is about 0.01. The results indicate that the measurement system can measure friction torque and its inhomogeneity effectively and can be used in measurement of friction torque on other ASSM.

Abstract: Wind-driven rain or driving rain is a rain which has given a horizontal velocity component by the wind. It can be the important moisture source for building façades and has been of the great concern in building science. In this article, the normative method described in STN EN ISO 15927-3:2009, was used for calculation of driving rain impact on vertical surfaces. This amount of rain was compared to the CFD simulation for selected location and to the experimental measurement carried out by wind-driven rain gauge.

Abstract: The vertical jump is a commonly used test and widely studied in literature. Indeed, it is one of the most prevalent method of assessment on sport performance because the jump height is highly correlated with leg extensor muscles power. This paper deals with the study on a new contact mat system whose performances have been compared with a force platform. Some tests have been performed and the relative comparative results will be presented. The study shows a significant concurrent validity of Wi-JumpLe system for the flight and ground contact time measurements. In conclusion, the new contact mat structure together with the electronic measurement system is legitimate to assess vertical jump height and leg extensors muscle power.

Abstract: The design of industrial hot metal forming processes nowadays is mostly carried out using commercial Finite Element (FE) software codes. For precise FE simulations, reliable material properties are a crucial factor. In bulk metal forming, the most important material property is the materials flow stress, which determines the form filling and the necessary forming forces. At elevated temperatures, the flow stress of steels is determined by strain hardening, dynamic recovery and partly by dynamic recrystallization, which is dependent on strain rate and temperature. To simulate hot forming processes, which are often characterized by rapidly changing strain rates and temperatures, the flow stress is typically derived from flow curves, determined at arbitrary constant temperatures and strain rates only via linear interpolation. Hence, the materials instant reaction and relaxation behavior caused by rapid strain rate changes is not captured during simulation. To investigate the relevance of the relaxation behavior for FE simulations, trails with abrupt strain rate change are laid out and the effect on the material flow stress is analyzed in this paper. Additionally, the microstructure evolution due to the strain rate change is investigated. For this purpose, cylinder compression tests of an industrial case hardening steel are conducted at elevated temperatures and different strain rates. To analyze the influence of rapid strain rate changes, changes by one power of ten are performed at a strain of 0.3. As a reference, flow curves of the same material are determined at the initial and final constant strain rate. To investigate the microstructure evolution, compression samples are quenched at different stages, before and after the strain rate change. The results show that the flow curves after the strain rate change tend to approximate the flow curves measured for the final strain rate. However, directly after the strain rate change significant differences between the assumed instant flow stress and the real material behavior can be observed. Furthermore, it can be shown that the state of dynamic recrystallization at the time of the strain rate change influences the material response and relaxation behavior resulting in different slopes of the investigated flow curves after the strain rate change.

Abstract: Spectral analysis of different profiles obtained during straightness deviation measurement was performed. The several profiles are showed, for which the value of straightness deviation is the same, but its behavior differs greatly. Spectral parameters characterizing the type of straightness deviation are proposed. The automated system based on factors of fuzzy-set theory with implementation in the form of neural network is developed.

Abstract: Electromagnetic actuators are used in a variety of technical applications especially in the automotive industry. In-line process control methods are an essential component of the Lean and Six Sigma methodology to ensure process quality. However, the current state of the art in process and quality control is largely limited to end-of-line measurements of the force output. Analysing the magnetic stray field is a promising method that can be used to draw conclusions on the properties and defects of the flux-conducting magnetic materials. This phenomenon can potentially be used to identify defects in magnetic actuators thus allowing inline quality-monitoring. In order to realize this feature, patterns in the magnetic stray field of an actuator have to be identified and linked to a specific defect. The resulting challenge is the analysis of large datasets in order to characterize the stray field anomalies. This paper summarizes the results of a study on linear magnetic actuators trying to prove a relationship between parasitic magnetic stray field and the overall force output of an actuator by analysing the data with statistical methods. The findings of this study suggest that certain statistical methods, like regression, are not well suited to build a prediction model for defects in actuators using a similar approach of measuring stray field outside the actuator. This is mainly due to the fact that prerequisites for model building are difficult to full fill within the context of stray field analysis. Nevertheless, the findings also suggest that methods of exploratory data analysis can be used to derive quality relevant information from data of stray field measurements. The paper elaborates on the problem of defining a population, choosing variables for model building, as well as model error.

Abstract: ISO/TC206 'Fine ceramics' is one of a technical committee (TC) in the International Organization for Standardization (ISO), established in 1992. The first plenary meeting for this TC was held in 1994, and the latest meeting was held in August 2015, in Jeju, Republic of Korea. The scope of this TC covers very wide field concerning the ceramic materials for industrial applications, in forms of powders, monoliths, coatings and composites, and in functions of mechanical, thermal, chemical, electrical, magnetic, optical and their combinations. This TC consists of 18 participating member (P-member) countries and 13 observing member (O-member) countries. We already have 81 published standards from this TC. About 30 new work items are under discussion, about 15 items are waiting for starting the discussion, and about 10 items are in the process for revision of the published standards. In this TC, we have 12 working groups. More than twenty years have passed since starting this TC, generally speaking, the categories of the discussed items tends to shift, from some testing methods for fundamental properties (strength, density, thermal properties etc.), to some properties for specified applications, such as ceramic bearing materials, photocatalytic materials and electrical applications.