IE Method Research Articles

Impact-echo method for the deterioration evaluation of near-surface mounted CFRP strengthening under outdoor exposure conditions

This paper discusses the feasibility of using the impact-echo method (IE method) to evaluate the deterioration of near-surface mounted carbon fiber reinforced polymer (NSM CFRP) strengthening under outdoor exposure. In NSM CFRP strengthening materials, CFRP bars are embedded in pre-cut grooves on the surface of reinforced concrete members and the grooves are filled with epoxy. Prolonged outdoor exposure reduces the bonding strength of epoxy and generates debonding flaws at epoxy–concrete interfaces, preventing CFRP bars from fully exerting their material strength and inhibiting the reinforcement effectiveness of NSM CFRP. The IE method based on the principle of stress wave propagation was adopted in this study as a nondestructive technique for detecting debonding flaws at epoxy–concrete interfaces caused by the prolonged outdoor exposure of the NSM CFRP strengthening members. Firstly, the IE tests were conducted on the NSM CFRP beams without outdoor exposure. The IE spectra showed high-amplitude peaks at the dominant frequencies associated with the cross sectional mode of vibration of the NSM CFRP beams. Subsequently, the strengthening surfaces of the NSM CFRP beams were exposed to direct sunlight under outdoor environments. The IE and loading tests were conducted when the beams were exposed to the outdoor environment for 4, 8, 12, and 48 months. The experimental results indicated that prolonged outdoor exposure generated the debonding flaws at the epoxy–concrete interfaces and the IE method can be used to detect the interfacial debonding by identifying the decrease in the dominant frequencies. For a NSM CFRP beam with debonding interfaces, the result obtained from loading test revealed a decrease in the load-carrying capacity due to damages at the epoxy–concrete interfaces resulting in the inability of the CFRP bars to fully exert their material strength. Therefore, the IE method is applicable for assessing the deterioration of the NSM CFRP strengthening members under prolonged outdoor exposure.

Detecting debonding flaws at the epoxy–concrete interfaces in near-surface mounted CFRP strengthening beams using the impact–echo method

This paper discusses the feasibility of using the impact–echo method (IE method) to assess the debonding flaws at the epoxy–concrete interfaces of near-surface mounted carbon fiber reinforced polymers (NSM CFRPs). The effectiveness of NSM CFRP strengthening is influenced by whether epoxy bonds CFRP bars and existing concrete structures effectively and thoroughly, thereby mutually transmitting the stress in the reinforced zones with CFRP bars. Because of poor construction quality, aging, and deterioration, debonding occurs between epoxy and concrete surfaces, severely inhibiting the reinforcement effectiveness of NSM CFRPs. The IE method is based on the principle of stress waves and was adopted in this study as the nondestructive debonding flaw assessment technique. To clarify the characteristics of the stress wave propagation caused by impact forces on NSM CFRP structures, numerical analysis and experimental test were performed on the bar-like epoxy specimens with a cross-sectional size of 13×13mm. The types of specimens used in this study included the bar-like pure epoxy specimen, bar-like epoxy specimens containing CFRP bars, and the concrete beams containing bar-like epoxy specimens with and without CFRP bars. For the concrete beams embedded with bar-like epoxy specimens, various debonding statuses at the epoxy–concrete surfaces were considered. The numerical analysis revealed that the impact responses in the bar-like pure epoxy specimen and bar-like epoxy specimens containing CFRP bars were dominated by the first few cross-sectional modes of vibration, and the IE test verified this result. The numerical and experimental results indicated that for the concrete beams containing bar-like epoxy specimens with and without CFRP bars and without debonding flaws, the impact response spectra each featured one high-amplitude peak at the fundamental mode frequency, referred to as the dominant frequency. When debonding occurred at the epoxy–concrete interfaces of the concrete beams containing bar-like epoxy specimens with and without CFRP bars, the impact responses showed that the dominant frequencies decreased significantly. When the dominant frequencies instead increased to levels nearly equal to those of the fundamental frequencies of the bar-like epoxy specimens, the epoxy thoroughly debonded from the concrete interfaces. According to the characteristics of the aforementioned impact responses, the IE method is capable of detecting the debonding flaws at epoxy–concrete interfaces in NSM CFRP strengthening.

Strategi Peningkatan Kinerja Penyuluh Pertanian dalam Pengembangan Agribisnis di Kabupaten Banyuwangi

<p>Agribusiness development in Banyuwangi growing supported by the agricultural extension. The role of agricultural extension is needed by communities and farmers. Therefore, strategies are needed to improve its performance, especially with the implementation of the difference between the central government and local governments (regional autonomy). Research related to strategies for improving the performance of agricultural extension workers, especially in Banyuwangi has been done by first analyzing the factors that affect the performance of the extension, which is then analyzed more in depth with the IE method, SWOT and QSPM and eventually obtained agricultural extension strategies for improving performance. The results showed that the strength factor is the suitability of a high enough salary, weakness factor is the lack of monitoring of the performance of agricultural extension, chances are the interest factor be enough agricultural extension, the threat factor is the lack of agricultural extension PNS. Strategic priorities for performance improvement of agricultural extension is the need to evaluate the performance of agricultural extension monitoring periodically, the second priority is additional quota admission counselor civil servants, the third priority the strengthening of IT, the fourth priority intensification of agricultural extension training programs to improve the performance of the performance competencies of agricultural extension, the fifth priority the improvement of cooperation among government agencies to integrate all of the work program for the right target, and the sixth priority poktan role to participate in the establishment of monitoring the performance of agricultural extension. While the managerial implications in the development of agribusiness, there are three themes, namely human resource development extension agent, performance evaluation, and monitoring the performance of agricultural extension.</p><p>Keywords: The performance of the agricultural instructor, Banyuwangi agribusiness development, strategic priorities,managerial, implication</p>

Generation and evaluation of gamma-ray buildup factors prepared as the standard data in the Atomic Energy Society of Japan

c A data set of gamma-ray buildup factors for point isotropic sources has been generated by the method of invariant embedding. Specific features of the data set as compared with the ANSI/ANS-6.4.3 standard published by the American Nuclear Society are 1) the data corresponding to effective dose with AP and ISO irradiation geometries, and ambient dose equivalents are added, 2) the distance from the source is extended up to 100 mean free paths (mfp) from 40 mfp in the ANS data, 3) the method of invariant embedding and the photon cross section PHOTX are used consistently for all materials, and 4) treatment of bremsstrahlung is improved by using the bremsstrahlung production data calculated by the EGS4 code. The accuracy of the transport calculations for exposure buildup factors by the IE method was evaluated quantitatively by works including 1) comparison of buildup factors with those obtained by the moments method in the ANS data, 2) comparison of the buildup factors with those obtained by the EGS4 code, and 3) self evaluation of influence of mesh width in space, energy and angle in the numerical solution of transport equation by the IE method. It is concluded that the magnitude of error in the present data is estimated about 10% or less up to 40 mfp.

Parameter search of geometric-progression formula for gamma-ray isotropic point source buildup factors up to depths of 100 mfp, including contribution of secondary radiations

The form of K(E,X) in the Geometrical Progression (G-P) fitting function for 28 single-material gamma-ray buildup factors was improved to accurately approximate for deep penetration up to 100 mean free paths (mfp). The reference data were generated with Invariant Embedding (IE method) code treated Klein-Nishina scattering cross section accurately, included all secondary radiations of fluorescence and bremsstrahlung, and covered the energy range 0.015-15 MeV and up to 100 mfp. The search procedure of fitting parameters to gamma-ray buildup factors was revised from the least squares fit (LSF) to the minimization of maximum fractional deviation (MMD). Revised K(E,X) has 7 parameters. Here two values of Xk and Xm parameters were fixed, and the remainder parameters were determined using the (MMD). For an energy not listed in the reference, the values of G-P fitting parameters were determined using the interpolation method of Akima. By the same method the values of G-P fitting parameters for equivalent atomic number of a compound or a mixture were determined. The maximum errors of the present fitting parameters within 40 mfp were almost the same values to the ANSI/ANS-1991 or below. Those above 40 mfp were almost the same values within 40 mfp, or a little large.

Verification and application of continuous surface temperature monitoring technique for investigation of nocturnal sensible heat release characteristics by building fabrics

This study verified and applied a novel technique, continuous surface temperature monitoring (CSTM), developed by the authors to investigate the nocturnal sensible heat release characteristics by building fabrics. The CSTM technique uses infrared technology to estimate the nocturnal sensible heat (SH) transfer between building finishes materials and the surrounding environment without knowing the physical and thermal properties of the tested materials. Forty-seven repeated indoor test were carried out for verification with the traditional internal energy equation (IE method), i.e. the product of mass, heat capacity and temperature change. The results were delightfully satisfactory with only 1.8–5.2% of average discrepancy. The R2 value of 0.972 between the two methods suggested that the developed CSTM technique statistically fits well with sensible heat release calculated by IE method. This means that the CSTM technique can be used to estimate sensible heat release from an object with insignificant error. CSTM technique was then applied for investigating 13 building surfaces in Central, Hong Kong. The findings proved that CSTM technique can be applied on number of buildings simultaneously to investigate the sensible heat release characteristics of different types of building fabrics. The results showed that granite walls release more sensible heat than ceramic walls.

콘크리트 구조물 하부의 공동 탐지를 위한 충격반향(IE) 및 충격응답(IR) 기법의 모형 실험

The impact echo and impulse response methods were applied to the safety inspection of concrete structure, which has the rear cavity. The concrete structure model used in this study was divided into four sections, pure concrete, concrete+cavity, reinforced concrete with iron bar, and reinforced concrete+cavity, respectively. Previous study performed by authors have showed a possibility of success to use these method for detection of the rear cavity of concrete structure. Therefore, we tried to get more enhanced result with IE and IR methods through this study. Especially, IE and IR methods are relatively accurate to map the point of measurement, which makes it possible to interpret the depth of the concrete bed and effect by rear cavity with confidence. Followings were revealed from the results; the IE method shows some small peak zones probably indicating the rear cavity in the frequency lower than the resonance frequency and the changes of mobility and dynamic stiffness in the IR method indicate the weak zones. The proposed methods can be used to delineate the weak zones of the concrete structure.

Seismic response analysis of soil–structure interactive system using a coupled three-dimensional FE–IE method

This paper proposes a slightly new three-dimensional radial-shaped dynamic infinite elements fully coupled to finite elements for an analysis of soil–structure interaction system in a horizontally layered medium. We then deal with a seismic analysis technique for a three-dimensional soil–structure interactive system, based on the coupled finite–infinite method in frequency domain. The dynamic infinite elements are simulated for the unbounded domain with wave functions propagating multi-generated wave components. The accuracy of the dynamic infinite element and effectiveness of the seismic analysis technique may be demonstrated through a typical compliance analysis of square surface footing, an L-shaped mat concrete footing on layered soil medium and two kinds of practical seismic analysis tests. The practical analyses are (1) a site response analysis of the well-known Hualien site excited by all travelling wave components (primary, shear, Rayleigh waves) and (2) a generation of a floor response spectrum of a nuclear power plant. The obtained dynamic results show good agreement compared with the measured response data and numerical values of other soil–structure interaction analysis package.

Nonlinear optimal on-line heat-dissipation control methodology in electronic devices

The essential element in obtaining semiconductor electronic device enhanced reliability involves solving the heat-dissipating issue. Certain electronic components possess varying thermal properties and the strength of the heat generated by the semiconductor chip is unknown. Therefore, the heat dissipation control problem is both complicated and perplexing. This paper proposes a methodology, the LQG/IE tracking algorithm, to solve the nonlinear heat dissipation control problem. The IE method, which is a combination of an Extended Kalman filter and Recursive Least Squares Estimator, estimates (in real time) the unknown time-varying heat source generated by the semiconductor chip using temperature measurements of the package seal surface. The LQG tracking algorithm is adopted to analyze the feedback gain to control the heat dissipation. The simulation results reveal that an effective and optimal heat dissipation controller can be implemented for the cooling system using the LQG/IE tracking algorithm.

FVTD—integral equation hybrid for Maxwell's equations

AbstractA new hybrid finite‐volume time‐domain integral equation (FVTD/IE) algorithm for the solution of Maxwell's Equations on unstructured meshes of arbitrary flat‐faceted volume elements is presented. A time‐domain IE‐based numerical algorithm is applied on the boundary of the computational domain to determine the incoming fluxes for the boundary facets of the mesh. This method is a global grid‐truncation technique similar to the method previously introduced for the finite‐difference time‐domain scheme by Ziolkowski et al. The three main advantages of this IE truncation method are that (1) it allows geometrical objects to be located (almost) arbitrarily close to the mesh boundaries without compromising the physics of the problem, (2) it couples the physics of unconnected meshes so that distant scatterers can be surrounded by their own local mesh, thus reducing total mesh size, and (3) the same IE formulation can be used to compute electromagnetic field values at points outside the mesh. Currently, the main disadvantage is that an acceleration scheme for performing the IE update, which requires integrating field components on an interior surface at a retarded time, is not available. Computational results are presented for the scattering from a perfectly electrical conducting sphere and compared numerically with the analytic time‐domain solution as well as the solution obtained using a large spherical outer mesh boundary with local absorbing boundary conditions. Results are excellent and show almost no reflections from the mesh boundary even when the observation point is located close to the corner of the cubically shaped outside mesh boundary. Results are also presented and validated for the scattering from two objects that are contained inside their own unconnected meshes. Copyright © 2007 John Wiley & Sons, Ltd.

Activated bovine cytoplasts prepared by demecolcine-induced enucleation support development of nuclear transfer embryos in vitro

Demecolcine-induced enucleation (IE) of mouse oocytes has been shown to improve development to term of cloned mice. In this study, we characterized the kinetics and morphological progression of bovine oocytes subjected to IE, and evaluated their ability to support embryo development to the blastocyst stage after nuclear transfer (NT). In vitro matured bovine oocytes were parthenogenetically activated and subsequently exposed to demecolcine at various times post-activation. Onset and duration of demecolcine treatment significantly altered activation and IE frequencies, which varied from 7.1% to 100% and 33.3% to 91.7%, respectively, at 5 hr post-activation. A significant decrease in IE frequencies was observed at 17 hr post-activation (3.4%-46.1%), possibly due to reincorporation of chromosomes into the oocyte after incomplete second polar body (PB) extrusion. Oocytes were reconstructed by NT before (treatment 1) or after (treatment 2) activation and demecolcine treatment, and cultured in vitro. Cleavage (48.1%-54.2%) and blastocyst rates (15.7%-19%) were equivalent for the two treatments, as well as the total cell number in NT blastocysts. Furthermore, most of the blastocysts were completely diploid (treatment 2) or heteroploid but with a majority of diploid nuclei (treatment 1). Our results demonstrate that the IE method can be successfully used to produce enucleated bovine cytoplasts that are competent to support development to the blastocyst stage after NT. This technically simple approach may provide a more efficient method to enhance the success rate of NT procedures. Further studies are needed to improve the in vitro development efficiency and to expand our understanding of the mechanism(s) involved in demecolcine-induced enucleation.

Full-Wave Analysis of Photonic Bandgap Integrated Optical Components by the TLM-IE Method

This paper presents the full-wave analysis of commonly encountered optical periodic structures by the novel transmission-line matrix/integral equation (TLM-IE) method. The TLM-IE is a three-dimensional full-wave hybrid technique that combines the advantages of the numerical TLM method in dense finite regions and those of the IE method in open regions where simple Green functions are available. The pre- and postprocessing tools of the TLM-IE solver provide visualization and physical insight into the dynamics of electromagnetic propagation in such devices. The aim of this effort is twofold: 1) to analyze the diffraction and reflection characteristics of photonic bandgap gratings and 2) to define optimization guidelines for the Q factor of integrated dielectric resonators.

Inquiry-Events as a Tool for Changing Science Teaching Efficacy Belief of Kindergarten and Elementary School Teachers

Researchers agree that science education should begin at childhood, due to its contribution to later cognitive skill development. However, in most cases only a small portion of kindergarten and elementary school activities is related to science. Given the tremendous impact teachers have on children and on the success or failure of their curriculum, teachers' efficacy belief toward science teaching (TEBTST) should be of significant concern. It is suggested herein that in order to improve TEBTST, the science curriculum should be developed not only from the perspective of the child's needs, but will explicitly consider the teachers' needs as well. Such an approach is described in this study, and is labeled as the “Inquiry Events” (IE) teaching method. This method involves relating to an open-ended problem situated in real life, that encourages investigation of a variety of issues—ethical, economic, scientific, etc.—which both kindergarten and elementary school teachers are accustomed to considering. The method encourages teachers to relate to these daily situations by introducing scientific questions, which they would ordinarily ignore or omit. Using the STEBI (Science Teaching Efficacy Beliefs Instrument) questionnaire before and after a 4-day workshop introducing the IE method, it was found that IE improved TEBTST and increased their confidence in teaching science.

A simple technique for increased sensitivity in immunoelectrophoresis by the use of antiserum against IgG

Precipitates in two-dimensional immunoelectrophoresis (2D-IE) plates can be amplified by the application of an antiserum against IgG after the second dimension run. Thereby, the sensitivity of the IE method is increased; faint precipitates and antigen-antibody reactions close to but below the level of forming recognizable precipitates are made visible. The advantage of the method was demonstrated for a multilinear Mycobacterium phlei system.