Operation load estimation of chain-like structures using fiber optic strain sensors

Armen Derkevorkian,Francisco Pena,Sami F. Masri,W. Lance Richards4 국제구조공학회 2017 Smart Structures and Systems, An International Jou Vol.20 No.3

The recent advancements in sensing technologies allow us to record measurements from target structures at multiple locations and with relatively high spatial resolution. Such measurements can be used to develop data-driven methodologies for condition assessment, control, and health monitoring of target structures. One of the state-of-the-art technologies, Fiber Optic Strain Sensors (FOSS), is developed at NASA Armstrong Flight Research Center, and is based on Fiber Bragg Grating (FBG) sensors. These strain sensors are accurate, lightweight, and can provide almost continuous strainfield measurements along the length of the fiber. The strain measurements can then be used for real-time shape-sensing and operational load-estimation of complex structural systems. While several works have demonstrated the successful implementation of FOSS on large-scale real-life aerospace structures (i.e., airplane wings), there is paucity of studies in the literature that have investigated the potential of extending the application of FOSS into civil structures (e.g., tall buildings, bridges, etc.). This work assesses the feasibility of using FOSS to predict operational loads (e.g., wind loads) on chain-like structures. A thorough investigation is performed using analytical, computational, and experimental models of a 4-story steel building test specimen, developed at the University of Southern California. This study provides guidelines on the implementation of the FOSS technology on building-like structures, addresses the associated technical challenges, and suggests potential modifications to a load-estimation algorithm, to achieve a robust methodology for predicting operational loads using strain-field measurements.

H2-MHR PRE-CONCEPTUAL DESIGN SUMMARY FOR HYDROGEN PRODUCTION

Richards, Matt,Shenoy, Arkal Korean Nuclear Society 2007 Nuclear Engineering and Technology Vol.39 No.1

Hydrogen and electricity are expected to dominate the world energy system in the long term. The world currently consumes about 50 million metric tons of hydrogen per year, with the bulk of it being consumed by the chemical and refining industries. The demand for hydrogen is expected to increase, especially if the U.S. and other countries shift their energy usage towards a hydrogen economy, with hydrogen consumed as an energy commodity by the transportation, residential and commercial sectors. However, there is strong motivation to not use fossil fuels in the future as a feedstock for hydrogen production, because the greenhouse gas carbon dioxide is a byproduct and fossil fuel prices are expected to increase significantly. An advanced reactor technology receiving considerable international interest for both electricity and hydrogen production, is the modular helium reactor (MHR), which is a passively safe concept that has evolved from earlier high-temperature gas-cooled reactor (HTGR) designs. For hydrogen production, this concept is referred to as the H2-MHR. Two different hydrogen production technologies are being investigated for the H2-MHR; an advanced sulfur-iodine (SI) thermochemical water splitting process and high-temperature electrolysis (HTE). This paper describes pre-conceptual design descriptions and economic evaluations of full-scale, nth-of-a-kind SI-Based and HTE-Based H2-MHR plants. Hydrogen production costs for both types of plants are estimated to be approximately $2 per kilogram.

COMMUNICATIVE NEEDS IN FOREIGN LANGUAGE LEARNING

Richards, Jack C. 全北大學校 語學硏究所 1982 어학 Vol.9 No.-

LOCALIZATION AND MULTIPLICATION OF DISTRIBUTIONS

Richards, Ian,Youn, Hee-Kyung K. Korean Mathematical Society 2000 대한수학회지 Vol.37 No.3

Working within classical distribution theory, we develop notions of multiplication and convolution for tempered distributions which are general enough to encompass the classical cases -such as pointwise multiplication of continuous functions or the convolution of $L^1$ functions- which most textbook treatments of distribution theory leave out. Pains are taken to develop a theory which satisfies the commutative and asociative laws.

A 6 m cube in an atmospheric boundary layer flow -Part 2. Computational solutions

Richards, P.J.,Quinn, A.D.,Parker, S. Techno-Press 2002 Wind and Structures, An International Journal (WAS Vol.5 No.2

Computation solutions for the flow around a cube, which were generated as part of the Computational Wind Engineering 2000 Conference Competition, are compared with full-scale measurements. The three solutions shown all use the RANS approach to predict mean flow fields. The major differences appear to be related to the use of the standard $k-{\varepsilon}$, the MMK $k-{\varepsilon}$ and the RNG $k-{\varepsilon}$ turbulence models. The inlet conditions chosen by the three modellers illustrate one of the dilemmas faced in computational wind engineering. While all modeller matched the inlet velocity profile to the full-scale profile, only one of the modellers chose to match the full-scale turbulence data. This approach led to a boundary layer that was not in equilibrium. The approach taken by the other modeller was to specify lower inlet turbulent kinetic energy level, which are more consistent with the turbulence models chosen and lead to a homogeneous boundary layer. For the $0^{\circ}$ case, wind normal to one face of the cube, it is shown that the RNG solution is closest to the full-scale data. This result appears to be associated with the RNG solution showing the correct flow separation and reattachment on the roof. The other solutions show either excessive separation (MMK) or no separation at all (K-E). For the $45^{\circ}$ case the three solutions are fairly similar. None of them correctly predicting the high suctions along the windward edges of the roof. In general the velocity components are more accurately predicted than the pressures. However in all cases the turbulence levels are poorly matched, with all of the solutions failing to match the high turbulence levels measured around the edges of separated flows. Although all of the computational solutions have deficiencies, the variability of results is shown to be similar to that which has been obtained with a similar comparative wind tunnel study. This suggests that the computational solutions are only slightly less reliable than the wind tunnel.

REVISITING CLASSROOM OBSERVATION

RICHARDS, JACK C. 中央大學校 韓國敎育問題硏究所 1997 韓國敎育問題硏究所論文集 Vol.- No.12

Observation of experienced teachers has always played an important role in teacher education. Traditional views of observation argue that through observing how teachers conduct their lessons, solve problems of classroom management, and interact with students, novice teachers can develop a repertoire of strategies and techniques which they can apply in their own teaching (Good & Brophy, 1987). Day (1990, 43) describes the following goals for classroom observation: * developing a terminology for understanding and discussing the teaching process * developing an awareness of the principles and decision making that underlie effective teaching * distinguishing between effective and ineffective classroom practices * identifying techniques and practices student teacher can apply to their own teaching Observation is often based on the assumption that acquiring skill in teaching involves learning how to do things, that is, on the mastery of specific types of behaviors, and that these are observable in the lessons of good teachers. As Acheson and Gall (1987, 28) point out: The first perspective for identifying characteristics of effective teaching is to examine what teachers do in the classroom. Typical how to dimensions of teaching which can form the focus of observation include: * how the teacher starts and ends a lesson * how the teacher allots times within a lesson * how the teachers assigns tasks to students * how the teacher organises learning groups * how the teacher supervises students while they are learning * how the teacher asks questions * how the teacher reinforces student answers Since observation appears to be relatively simply activity to organise and one which offers immediate tangible benefits it is not surprising that it plays a core role in many ESL/EFL teacher education programs. However what we can expect to gain from observation is dependent upon how we understand the nature of teaching. While teaching would appear to be an observable phenomenon, only aspects of it in fact are observable. For example underlying such an apparently straightforward issue as the type of questions a teacher uses when exploring a topic within a lesson(e.g. whether she asked high-order or low-order questions), life more complex issues concerning such things as why the teacher opted for one type of question as opposed to another. The ability to ask higher-order questions is a competency; clarity is not. There are times when higher-order questions are inappropriate, when the teacher who can ask them should not do so; there is no time when clarity is inappropriate. Research on teacher competencies must take account not only of how teachers behave, but when and why they behave as they do.(Medley 1979, 16). In other words the significance of what is observed, depends on the theory of teaching (or the particular approach or methodology) the teacher holds. One teacher may subscribe to a learner-centred philosophy of teaching and believe that learners acquire a second language through engagement with meaningful interactive tasks at an appropriate level of difficulty. Hence she provides a minimum of teacher intervention during a lesson. Another teacher may believe in the need to provide learners with a structured learning program to follow. incorporating explicit grammar focused tasks Consequently both teachers classroom behaviours may differ significantly with respect to key elements of a lesson and cannot be understood without knowing the philosophy of teaching(or the maxims) the teacher is operating from. It is for this reason that when different people discuss the same lesson (e.g. a teacher, a supervisor, and a student-teacher) they often give contradictory accounts of the same event(Fanslow, 1977). In using classroom observation in language teacher education program it is therefore necessary to go beyond a focus on the identification of the techniques and strategies experienced teachers employ and to use observation as a way of collecting information that can be used to develop a deeper understanding of how and why teachers teach the way they do and the different ways teachers approach their lessons. In this paper observation will be examined in terms of how it can assist both co-operating teachers(those who are observed) and novice teacher develop a reflective approach to teaching.

혼자 배우는 解剖와 生理(36)

Richards, Ralp,Chapman, David F. 임상약학사 1987 臨床藥學 Vol.7 No.11

Pedestrian level wind speeds in downtown Auckland

Richards, P.J.,Mallinson, G.D.,McMillan, D.,Li, Y.F. Techno-Press 2002 Wind and Structures, An International Journal (WAS Vol.5 No.2

Predictions of the pedestrian level wind speeds for the downtown area of Auckland that have been obtained by wind tunnel and computational fluid dynamic (CFD) modelling are presented. The wind tunnel method involves the observation of erosion patterns as the wind speed is progressively increased. The computational solutions are mean flow calculations, which were obtained by using the finite volume code PHOENICS and the $k-{\varepsilon}$ turbulence model. The results for a variety of wind directions are compared, and it is observed that while the patterns are similar there are noticeable differences. A possible explanation for these differences arises because the tunnel prediction technique is sensitivity to gust wind speeds while the CFD method predicts mean wind speeds. It is shown that in many cases the computational model indicates high mean wind speeds near the corner of a building while the erosion patterns are consistent with eddies being shed from the edge of the building and swept downstream.

When Should ACE Inhibitors be First-Line therapy?

Richards, A.M. Medical Publications Korea 1996 Medical Progress Vol.18 No.1

Combination Antihypertensives : What Do They Offer?

Richards, Mark Medical Publications Korea 1991 Medical Progress Vol.13 No.11