Search

Long-term population monitoring is very important for the conservation of threatened and endangered species. The Black-faced Spoonbill Platalea minor is a globally endangered species and the majority of its population breed on uninhabited islands off the west coast of the Korean Peninsula. The Chilsan Archipelago in the southwest is the southernmost breeding site for this species in Korea and is expected to help buffer the potential dispersal of Black-faced Spoonbills from breeding populations currently concentrated in the Gyeonggi Bay area. As there has been a lack of information regarding the number of Black-faced Spoonbills, their characteristics, and their recent population trends, the present study investigated the population trends of Black-faced Spoonbills breeding in the Chilsan Archipelago. The study, from 2014 to 2018, examined breeding success in 2015 and 2018, and the size and location of nests in 2018. The number of nests ranged from 43 to 163 (2014, 43; 2015, 93; 2016, 84; 2017, 85; 2018, 163). The percentage of birds that attempted breeding between April and May was 84.9% in 2015 and 87.1% in 2018, while the breeding success rate was 69.9% in 2015 and 81.5% in 2018. The average nest size in 2018 was 55.06±6.09 cm long and 53.44±6.56 cm wide, while the average surface slope below the nest was 25.42±6.95°. In total, nine plant species were used as vegetation for nests. During the present study, the environmental conditions and the presence of anthropogenic disturbances seemed to affect breeding success. Therefore, strictly controlled access to breeding sites and effective management are needed to protect and conserve breeding populations of this endangered species.

This study is aimed to identify the external features of the water spiders (Argyroneta aquatica) collected from “The Natural Monument No. 412 Yeoncheon Eundaeri Water Spider Habitat” through observation of their microstructures using a scanning electron microscope. There is no study on the microstructures of the water spiders excluding several studies on protection plans and ecological investigations, thus giving this study considerable academic significance. Based on the scanning electron microscopy analysis, the water spider has eight simple eyes, and both of its lateral simple eyes are stuck together. A lateral bump was confirmed on the upper jaw, and the pedipalps had six joints and the legs had seven joints. The abdomen and sternum of A. aquatica have more hairs compared with those of land spiders, and its structure shows an elongated area of contact with the air bell so that the air bell can become attached to the abdomen better.

An intranasally active glucagon-like peptide-1 (GLP-1) formulation would have great advantages over conventional injectable therapies for the treatment of diabetic patients. The purpose of this study was to investigate the biological potentials of PEGylated exendin-4 (PEG-Ex4) analogs administered intranasally and the effects of polyethylene glycol (PEG) molecular weight (1, 2, 5 kDa) on nasal absorption. Initially, PEGEx4 analogs were site-specifically PEGylated to Lys²⁷-amine, and their bioactivities and stabilities were studied in vitro. The hypoglycemic effects and pharmacokinetics of these analogs after nasal administration were evaluated in type 2 diabetic animal models. PEG-Ex4 analogs had 3.1-, 3.8-, and 5.9-fold increased stabilities in rat nasal homogenates than Ex4. However, Lys²⁷-PEG(1k)-Ex4 was found to have well-preserved bioactivities (83.3% potency vs. Ex4), and other analogs were found to have much lower bioactivities than Lys²⁷-PEG(1k)-Ex4. In particular, the in vivo pharmacokinetic parameters of Lys²⁷-PEG(1k)-Ex4 in intranasally administered rats were significantly improved by PEGylation. Area under the curve (AUC) values of Lys²⁷-PEG(1k)-Ex4 were 33.6-fold higher and circulating t(1/2) values was 27.1-fold higher than Ex4. But, other analogs were not effectively absorbed via the intranasal route, because the higher molecular weight PEG (over 2 kDa) limited intranasal absorption. Finally, in vivo hypoglycemic experiment showed that Lys²⁷-PEG(2k)-, Lys²⁷-PEG(5k)-Ex4 had significantly lower hypoglycemic efficacies than Lys²⁷-PEG(1k)-Ex4, probably because of their lower intrinsic bioactivities and intranasal absorptions. Taken together, our findings suggest that the site-specific conjugation of appropriately sized PEG (1 kDa) substitution onto peptides like Ex4 offers two advantages for deliveryvia the intranasal route, namely, increased stability and extended circulating half-life.

The real-time hybrid testing method (RT-HYTEM) is a structural testing technique in which the numerical integration of the equation of motion for a numerical substructure and the physical testing for an experimental substructure are performed simultaneously in real-time. This article presents the quantitative evaluation of the seismic performance of a building structure installed with a magnetorheological (MR) damper using RT-HYTEM. A building model is identified from the force-vibration testing results of a full-scale five-story building and is used as the numerical substructure, and an MR damper corresponding to an experimental substructure is physically tested using a universal testing machine (UTM). First, the force required to drive the displacement of the story, at which the MR damper is located, is measured from the load cell attached to the UTM. The measured force is then returned to a control computer to calculate the response of the numerical substructure. Finally, the experimental substructure is excited by the UTM with the calculated response of the numerical substructure. The RT-HYTEM implemented in this study is validated because the real-time hybrid testing results obtained by application of sinusoidal and earthquake excitations and the corresponding analytical results obtained using the Bouc-Wen model as the control force of the MR damper with respect to input currents are in good agreement. Also, the results from RT-HYTEM for the passive -on and -off control show that the structural responses did not decrease further by the excessive control force, but decreased due to the increase of the current applied to the MR damper. Also, two semi-active control algorithms (modulated homogeneous friction and the clipped-optimal control algorithms) are applied to the MR damper in order to optimally control the structural responses. To compare the RT-HYTEM and numerical results, Bouc-Wen model parameters are identified for each input current. The results of the comparison of experimental and numerical responses show that it is more practical to use RT-HYTEM in semi-active devices such as MR dampers. The test results show that a control algorithm can be experimentally applied to the MR damper using RT-HYTEM. This article provides a discussion on each algorithm with respect to the seismic performances.

In this study, nonlinear dynamic characteristics of a tuned liquid column damper (TLCD) varying with the amplitude of excitation input are investigated through shaking table tests and numerical model of a TLCD. The tuned mass damper (TMD) analogy of a TLCD is used to simplify the formulation, in which it involves equivalent viscous damping of the inherent nonlinear damping term of a TLCD. The equivalent TMD model of a TLCD shows that the dynamic behaviour of a TLCD is affected by the natural frequency, damping ratio and ratio of total liquid mass to the mass in horizontal column of a TLCD. Shaking table test is performed to obtain experimental transfer functions that describe the dynamic behaviour of a TLCD specimen subjected to a harmonic loading with various excitation amplitudes. Transfer functions for various excitation amplitudes are measured from shaking table acceleration to both the liquid displacement within a TLCD container and the control force produced by a TLCD specimen. In addition, the dissipation energy due to the inherent damping of a TLCD is measured from the shaking table test varying with excitation amplitude. The variation of design parameters of a TLCD according to the excitation amplitude is investigated by comparing the transfer functions obtained from the shaking table test to those derived from the TMD analogy of a TLCD. These results showed that both the natural frequency and the mass ratio of a TLCD are independent on the variation of excitation amplitude, while the damping ratio of a TLCD increases with larger excitation amplitude. Copyright © 2010 John Wiley & Sons, Ltd.

Unfunctionalized biaryl compounds were parallelly and combinatorially prepared by the traceless hydrogenolysis of biarylsulfonates supported on pentaerythritol. The hydrogenolysis using 2-propylmagnesium chloride in the presence of dppfNiCl2 efficiently generated corresponding biaryl derivatives without any memory of the support. The strategy using pentaerythritol as a small soluble support was disclosed to have a potential to combine the benefits of both SPOS and solution-phase reaction with fast reaction rate, facile isolation of intermediates, easy analysis of intermediates and atom economical manner. The novel tetrapodal support is expected to be an efficient substitute for polymeric supports in many circumstances.

In this study, the effectiveness of various semiactive control algorithms based on magnetorheological (MR) dampers is experimentally investigated for seismic protection of a full-scale five-story steel frame building structure. This may be the first experimental comparison of several semiactive control algorithms using a full-scale test structure. The MR damper-based control systems are realized, when an MR damper is designed by deriving a suboptimal design procedure considering optimization problem and magnetic analysis, and then a damper with the capacity of 1.0 ton is manufactured. In the experiments, a linear active mass driver and the linear shaker seismic simulation testing method are used to excite the building structure in order to match the full-scale building vibrate as if the building undergoes an earthquake. Under the four historical earthquakes and one filtered artificial earthquake, the performance of the semiactive control algorithms including the passive optimal case is experimentally evaluated. From the experimental results, one can conclude that the Lyapunov and semiactive neuro-control algorithms are appropriate in reducing accelerations of the structural system, and the passive optimal case and the maximum energy dissipation algorithm show the excellent performance in reducing the first floor displacement.

The objective of this study is to investigate design parameters of a tuned liquid column damper(TLCD), which is affected by various excitation amplitude, through shaking table test. Design parameters of a TLCD are examined based on the equivalent tuned mass damper(TMD) model of a TLCD, in which the nonlinear damping of a TLCD is transposed to equivalent viscous damping. Shaking table test is carried out for a TLCD specimen subjected to harmonic waves with various amplitude. Transfer functions are ratios of liquid displacement of TLCD and control force produced by a TLCD, respectively, with respect to the acceleration excited by a shaking table. They are derived based on the equivalent TMD model of a TLCD. Then, the variation of design parameters according to the excitation amplitude is examined by comparing analytical transfer functions with experimental ones. Finally, the dissipation energy due to the damping of a TLCD, which is experimentally observed from the shaking table test, is examined according to the excitation amplitude. Comparisons between test results and analytical transfer functions showed that natural frequencies of TLCD and the ratio of the liquid mass in a horizontal column to the total liquid mass do not depend on the excitation amplitude, while the damping ratio of a TLCD increases with larger excitation amplitude.

In this study, a tuned liquid mass damper (TLMD) was proposed to reduce bidirectional responses of building structures, and its control performance was experimentally evaluated. The proposed TLMD with only one device body reduces bidirectional responses of building structures by behaving as a TMD and a TLCD in the weak and strong axial directions of a building floor plan, respectively. First, the control performance of a TLMD mounted on a scale-downed single-degree-of-freedom building model was experimentally evaluated by exciting this system with an actuator. Then, the real-time hybrid shaking table testing method (RTHSTTM) was performed to assess the control efficiency of the total system by adopting the TLCD and the building model as the experimental and numerical parts, respectively. It was confirmed by comparing uncontrolled and controlled testing results that the proposed TLMD can be applied to reduce the responses in both the weak and strong directions of building structures. Also, the results from RTHSTTM showed that the performance of TLMD-controlled building structure can be accurately evaluated by this method only using a TLMD as the experimental part. Copyright © 2008 John Wiley & Sons, Ltd.

Shear wall systems in high-rise apartments are governed by the flexural behaviour of members such as a cantilever beam. The installation of the damper-brace system in a structure governed by flexural behaviour is not suitable. Because of the relatively high lateral stiffness of the shear wall, a load is not concentrated on the brace and the brace cannot perform the role of a damping device. In this paper, a friction damper that applies the flexibility of a shear wall is proposed in order to reduce the deformation of the structure. To evaluate the performance of the proposed friction damper, a nonlinear time history analysis is executed by the SeismoStruct analysis program, and a multiple vertical linear element model is used for simulating flexural behaviour of the shear wall. It is found that the control performance of the proposed friction damper is superior to that of a coupled wall with a rigid beam. In conclusion, this study verified that the optimal control performance of the proposed friction damper is equal to 45% of the maximum shear force induced in the middle floor beam with the rigid beam. Copyright © 2009 John Wiley & Sons, Ltd.

Friction-type reinforcing members (FRMs) developed for the purpose of enhancing the wind-resistant performance of transmission towers are tested experimentally. The FRMs, in the middle of which slotted bolted connections (SBCs) are installed, are placed on the outside of tower legs, and provide additional damping and stiffness to the tower structure under bending deformations. First, the SBCs used in the FRMs are tested for various frictional sliding interface conditions. Second, the FRMs are installed on a 1/2 scale plane tower substructure and cyclic loading tests are conducted. Energy dissipation capacity and effects from local deformations of the FRMs and joint slips are investigated. From the test results, remarkable energy dissipation capacity, reaching to the 2.4 times of that before the installation of the FRMs, is observed. However, the local deformation of the SBC and joint slip should be prevented for more reliable design of the FRMs.

Since the force generated by a magneto-rheological (MR) damper has large nonlinearity, the performance of an MR damper is dependent on response characteristics such as frequency and amplitude. Soil–structure interaction (SSI) is generally known to have a large effect on the seismic response of a building structure. In this study, the performance of an MR damper in mitigating the seismic response of a building structure is evaluated considering the SSI effects. First, the performance variance of an MR damper due to the change of the structural natural period is investigated by constructing its normalized response spectrum through the numerical analysis of many earthquake wave records and the natural period of a structure. The variable friction force of an MR damper is normalized by the structural base shear force, and its amplitude and decrement of response are quantitatively evaluated. Then, the response characteristics of the SSI system due to the lengthening of the structural natural period and various soil conditions are numerically evaluated based on the response spectrum analysis. Finally, the numerical results with and without considering the SSI effects are comparatively evaluated for the building structure with an MR damper. The comparison results show that the SSI effect should be considered in order that the undesirable effect of an MR damper on the structural control would not be neglected. Copyright © 2007 John Wiley & Sons, Ltd.

In this paper, a half-scaled substructure test was performed to evaluate the failure mode of an existing transmission tower subjected to wind load. A loading scheme was devised to reproduce the dead and wind loads acting on the prototype transmission tower. The load was enforced on the model structure using two actuators and a triangular jig mounted on the reduced model. Preliminary numerical analysis was carried out to evaluate the stability and member force of the specimen for the design load. When the substructured transmission tower was loaded by 270% of its maximum allowable buckling load, local buckling occurred in joints of leg members with weak constraints. From the experimental results, such as load–displacement curves, displacements, and strains of members, it was concluded that the local buckling was due to the additional eccentric force caused by unbalanced deformation of the specimen.

This paper deals with the numerical model of a bracing-friction damper system and its deployment using the optimal slip load distribution for the seismic retrofitting of a damaged building. The Slotted Bolted Connection (SBC) type friction damper system was tested to investigate its energy dissipation characteristic. Test results coincided with the numerical ones using the conventional model of a bracing-friction damper system. The placement of this device was numerically explored to apply it to the assumed damaged-building and to evaluate its efficiency. It was found by distributing the slip load that minimizes the given performance indicies based on structural response. Numerical results for the damaged building retrofitted with this slip load distribution showed that the seismic design of the bracing-friction damper system under consideration is effective for the structural response reduction.

High-rise apartments of shear wall system are governed by flexural behavior like a cantilever beam. Installation of the damper-brace system in a structure governed by flexural behavior is not suitable. Because of relatively high lateral stiffness of the shear wall, a load is not concentrate on the brace and the brace cannot perform a role as a damping device. In this paper, a friction damper applying flexibility of shear wall is proposed in order to reduce the deformation of a structure. To evaluate performance of the proposed friction damper, nonlinear time history analysis is executed by SeismoStruct analysis program and MVLEM(multi vertical linear element model) be used for simulating flexural behavior of the shear wall. It is found that control performance of the proposed friction damper is superior to one of a coupled wall with rigid beam. In conclusion, this study verified that the optimal control performance of the proposed friction damper is equal to 45 % of the maximum shear force inducing in middle-floor beam with rigid beam.

In this study, a seismic design methodology of the friction dampers based on the storey shear force distribution of an elastic building structure is proposed. First, using two normalization methods for the slip-load of a friction damper, numerical analysis of various single degree-of-freedom (SDOF) systems is performed. From this analysis, the effect of the slip-load and brace stiffness is investigated and optimal stiffness ratios of the brace versus primary structure are found. Second, from the numerical analysis for five multistorey building structures of different natural periods and numbers of story, reasonable decision method for the total number of installation floors, location of installation and distribution of slip-loads are drawn. In addition, an empirical equation on the optimal number of installation floor is proposed. Finally, the superiority of the proposed method compared to the existing design method is verified from numerical analysis.

This paper presents a design of a tuned liquid mass damper(TLMD) for controlling bi-directional response of high-rise building structure subjected to windload. The proposed damper behaves as a tuned mass damper(TMD) of which mass is regarded as the mass of a tuned liquid column damper(TLCD) and the case wall of the TLCD itself in one direction and the TLCD in the other direction. Because the proposed device has coupled design parameter along two orthogonal directions, it is very important to select designing components by optimal fine tuning. In the designing TLMD, for easy maintenance, the rubber-bearing with small springs was applied in TMD direction. In this study, the Songdo New City Tower 1A in Korea, which has been designed and constructed two TLCDs in order to control bi-directional response, was chosen as the model building structure. The results of rotation test proved the effectiveness of bi-directional behavior of TLMD.

Seismic control performance of MR dampers, which have severe nonlinearity, varies with respect to the dynamic characteristics of an earthquake such as magnitude, frequency and duration. In this study, the effects of excitation characteristics on the equivalent linear system of a building structure with the MR damper are investigated through numerical analysis for artificial ground motions generated from different response spectrums. The equivalent damping ratio of the structure with the MR damper is calculated using Newmark and Hall`s equations for ground motion amplification factors. It is found that the equivalent damping ratio of the structure with the MR damper is dependent on the ratio of the maximum friction force of the MR damper over excitation magnitude. Frequency contents of the earthquake ground motion affects the equivalent damping ratio of long-period structures considerably. Also, additional damping effect caused by interaction between the viscousity and friction of the MR damper is observed. Finally. response reduction factors for equivalent linear systems are proposed in order to improve accuracy in the prediction of the actual nonlinear response.

This paper presents real-time hybrid test method of large-scale MR damper applied to a building structure under seismic excitation. The real-time hybrid test using an actuator for the control performance evaluation of a MR damper controlling the response of earthquake-excited building structure is experimentally implemented. In the test, the building structure is used as a numerical part, on which a large-scale MR damper adopted as an experimental part was installed to reduce its response. At first, the force that is acting between a MR damper and building structure is measured from the load cell attached on the actuator system and is fed-back to the computer to control the motion of the actuator. Then, the actuator is so driven that the error between the interface displacement computed from the numerical building structure with the excitations of earthquake and the fed-back interface force and that measured from the actuator. The control efficiency of the MR damper used in this paper is experimentally confirmed by implementing this process of experiment on real-time.

The purpose of this study is to evaluate the performance of viscoelastic dampers (VEDs) practically used for enhancing the serviceability of a 46-story reinforced concrete residential building structure. Considering that a bracing system for the installation of VEDs is not appropriate for a residential building because it occupies a large interior space, a method for installing VEDs at the midspan of a horizontal beam connecting the core and exterior columns is proposed. These VEDs control the total structural response in a similar way to a general outrigger system. The results from numerical analysis indicate that VEDs are effective for reducing not only mean components but also fluctuating ones of wind-induced responses by providing additional damping as well as stiffness. Copyright © 2007 John Wiley & Sons, Ltd.

Two types of friction-type reinforcing members (FRM) are proposed for the purpose of upgrading wind resistant performance of a transmission tower and verified through cyclic loading tests. First, a suitable installation scheme of the FRM is investigated through numerical analysis. Tower-leg-reinforcing type and brace type installation schemes are examined, and numerical analysis shows that the latter is more effective due to the vertical cantilever type behavior of the transmission tower. Based on this result, two types of the FRMs, dissipating energy in slotted bolted connections, are proposed. The one utilizes the relative displacement between the FRM and the tower leg, and the other utilizes that between the separated angles consisting of the FRM as a slip deformation of the slotted bolted connection. Proposed FRMs are installed on each tower leg of the 1/2 scale substructure models of an actual transmission tower body. From cyclic loading tests, the latter type of the proposed FRMs dissipates energy more effectively and is less sensitive to the work tolerance and initial deformation.

In this study, a real-time substructuring technique for the shaking table test is proposed. The proposed technique adopts the upper part of the object structure as the experimental substructure and the lower part as the numerical substructure. The force exerted on the interface of the two separated substructures is calculated on-line using the feed-back from an absolute floor acceleration measurement. The acceleration at the interface of the two substructures is calculated through an on-line time history analysis of the numerical substructure and is used as a reference signal in the shaking table controller. The inverse transfer function of the shaking table is employed to minimize the errors between the reference signal and generated ground motion for the experimental substructure. Through a shaking table test, the validity and accuracy of the proposed technique is demonstrated, and a good agreement between experimental and numerical results is obtained.

Friction-type reinforcing members(FRM) to enhance the resistance to wind loads of a transmission tower through both stiffness strengthening and damping increase are energy dissipation devices that utilize bending deflection of a tower leg. In this paper, the hysteretic behavior of the transmission tower structure with FRMs was experimentally investigated through cyclic loading tests on a half scale substructure model. Firstly, the variation of friction forces and durability of the FRM depending on the type of friction-inducing materials used in the FRM were examined by performing the cyclic loading tests on the FRM. Secondly, cyclic loading tests of a half-scale two-dimensional substructure model of a transmission tower with FRMs were conducted. Test results show that the FRM, of which desired maximum friction force is easily regulated by adjusting the amplitude of the torque applied to the bolts, have stable hysteretic behaviors and it is found that there exists the optimum torque depending on a design load by investigating the amount of energy dissipation of the FRMs according to the increase of torque.

Seismic control performance of the magnetorheological (MR) damper, which has strong nonlinearity, varies with the dynamic characteristics of the structure and ground motion such as natural period, peak ground acceleration. The MR damper has a property of the friction damper so that the relative magnitude of the friction force over excitation intensity affects the control performance. In this study, through numerical analyses of single-degree-of-freedom (SDOF) structures, design spectra for the passive MR damper and optimal non-dimensional friction forces are suggested. Additionally, simple semi-active control algorithms modulating the friction force of the MR damper in accordance with structural responses are proposed and compared with each other and the passive MR damper. Finally, the condition that the semi-active control is more appropriate than the passive one is identified for reasonable selection of the control strategy.

A new equivalent linearization technique is proposed for a friction damper–brace system (FDBS) idealized as an elastoplastic system. The proposed equivalent linearization technique utilizes secant stiffness and dissipated energy based on the probability distribution of the extremal displacement of the FDBS. In addition, a conversion scheme to convert an elastically designed equivalent linear systems to a FDBS is given. For comparative study, an existing model update technique based on system identification is modified to constraint elements to be updated. For the purpose of verification, shaking table tests for a small scale three-story shear building model, in which a rotational FDBS is installed, are conducted and equivalent linear systems are obtained using the proposed technique and the model update technique. Natural frequencies, modal damping ratios and response quantities predicted by those equivalent linear systems are compared with experimentally obtained ones. Finally, effects of the maximum friction force on the proposed equivalent linearization technique are investigated through numerical analysis of SDOF systems with a FDBS.

In this study, the real-time hybrid test using a shaking table for the control performance evaluation of a U-shaped tuned liquid column damper (TLCD) controlling the response of earthquake-excited building structure is experimenttally implemented. In the test, the building structure is used as a numerical part, on which a U-shaped TLCD adopted as an experimental part was installed to reduce its response. At first, the force that is acting between a TLCD and building structure is measured from the load cell attached on shaking table and is fed-back to the computer to control the motion of shaking table. Then, the shaking table is driven such a manner that the error between the interface acceleration computed from the numerical building structure under the excitations of earthquake and the fed-back interface force and that measured from the shaking table. The control efficiency of the TLCD used in this paper is experimentally confirmed by implementing this process of shaking table experiment on real-time.

In this paper, a real-time hybrid shaking table testing method (RHSTTM) is experimentally implemented for evaluating the performance of a tuned liquid damper (TLD) controlling a seismically excited building structure. The RHSTTM does not require a physical building structural model in performing the experiment of a TLD–structure interaction system and it only uses a TLD and a shaking table. The structural responses of the interaction system are calculated numerically in real time using an analytical building model, a given earthquake record, and a shear force generated by the TLD, and the shaking table reproduces both the controlled and uncontrolled absolute acceleration of the TLD installed floor by modulating the feedback gain of the shear force signal measured by the load-cell positioned between the TLD and the shaking table. Comparison between the structural responses obtained by the RHSTTM and the conventional shaking table test of a single story steel frame with TLD indicates that the performance of the TLD can be accurately evaluated using the RHSTTM without the physical structural model. Finally, the uncontrolled and TLD-controlled structural responses of a three story structure are obtained by the RHSTTM in both time and frequency domains, showing that TLD can effectively mitigate the seismic responses of building structures.

In this study, the effects of bracing systems for installing a magnetorheological (MR) damper in a building structure on seismic response control are analytically and experimentally investigated. The performance of the toggle brace system which enables the installed damper to generate larger effective control force due to its response amplification mechanism than a conventional brace system is evaluated. In addition, the nonlinear velocity amplification factor for the toggle brace—MR damper system and the effect of toggle configuration are considered. Analytical and experimental results show that control performance can be enhanced using the toggle brace system especially for the case in which the MR damper installed using non-amplifying brace system cannot provide sufficient response reduction.

This paper presents electromagnetically actuated 2-axis scanning micromirror with large aperture and tilting angle for laser pointing applications such as LIDAR systems. The 2-axis micromirror with the plate size of 3 mm in diameter was fabricated using gimbaled single crystal silicon with a coil and assembled with permanent magnet forming radial magnetic field. The micromirror was realized on SiOG (Silicon on Glass) wafer using 4 photolithography masks and the magnet assembly was optimized to maximize the torque. Horizontal resonance frequency of manufactured micromirror was measured 1.421 kHz and vertical resonant frequency was 396 Hz. The vertical scan angle was 16.87°, 26.32° and 22.61 ° with the cylindrical magnet diameter of 2.6 mm, 4.0 mm and 4.8 mm respectively. Horizontal maximum scan angle was 24.45° using a cylindrical magnet with the diameter of 4.0 mm. Proposed 2-axial electromagnetically actuated large size micromirror is expected to be applicable to LIDAR system because it can handle high power laser and fast 2-dimensional scanning.

Forced vibration testing is important for correlating the mathematical model of a structure with the real one and for evaluating the performance of the real structure. There exist various techniques available for evaluating the seismic performance using dynamic and static measurements. In this paper, full scale forced vibration tests simulating earthquake response are implemented by using a hybrid mass damper. The finite element (FE) model of the structure was analytically constructed using ANSYS and the model was updated using the results experimentally measured by the forced vibration test. Pseudo-earthquake excitation tests showed that HMD induced floor responses coincided with the earthquake induced ones which were numerically calculated based on the updated FE model.

This paper proposes a shaking table test considering the dynamic soil strcuture interaction (SSI) by using the accelerations measured from superstructure and shaking table. The proposed method based on the substructure method is that only superstructure is used as an experimental model and dynamic soil stiffness is reflected on the controller of shaking table for soil model. At the moment, an experimental superstructure is excited by a shaking table with the motion required to emulate the dynamic behavior of total SSI system. First, the validity of the proposed method is verified by the verification model of numerical simulation, which is derived from the equation of motion of SSI system under consideration. Also, the applicability of the proposed method to shaking table test is numerically verified from the simulation model incorporating the transfer function of shaking table.

In this study, we attempted to prepare compounds with heterocyclic replacements for metabolically unstable esters of benzopyranyl indole-2-carboxylic esters, which showed good in vitro and in vivo cardioprotective efficacies possibly through the opening of mito chondrial ATP-sensitive potassium channel (KATP). Initially, we tried to construct indolin-2-yl-heterocycles using unprotected indoline-2-carboxylic acid, but the cyclization was proceeded with oxidation of the indoline ring to the indole, which didn’t react with benzopyranyl epoxide. Thus we introduced N-Boc group to deplete the electron density of the indoline ring. We successfully prepared various indolin-2-yl-heterocycles by the cyclization of the building blocks including carboxamide, β-hydroxy amide, hydrazide, nitrile starting from N-Boc-indoline-2-carboxylic acid.

An intranasally active glucagon-like peptide-1 (GLP-1) formulation would have great advantages over conventional injectable therapies for the treatment of diabetic patients. The purpose of this study was to investigate the biological potentials of PEGylated exendin-4 (PEG-Ex4) analogs administered intranasally and the effects of polyethylene glycol (PEG) molecular weight (1, 2, 5 kDa) on nasal absorption. Initially, PEGEx4 analogs were site-specifically PEGylated to Lys²⁷-amine, and their bioactivities and stabilities were studied in vitro. The hypoglycemic effects and pharmacokinetics of these analogs after nasal administration were evaluated in type 2 diabetic animal models. PEG-Ex4 analogs had 3.1-, 3.8-, and 5.9-fold increased stabilities in rat nasal homogenates than Ex4. However, Lys²⁷-PEG(1k)-Ex4 was found to have well-preserved bioactivities (83.3% potency vs. Ex4), and other analogs were found to have much lower bioactivities than Lys²⁷-PEG(1k)-Ex4. In particular, the in vivo pharmacokinetic parameters of Lys²⁷-PEG(1k)-Ex4 in intranasally administered rats were significantly improved by PEGylation. Area under the curve (AUC) values of Lys²⁷-PEG(1k)-Ex4 were 33.6-fold higher and circulating t(1/2) values was 27.1-fold higher than Ex4. But, other analogs were not effectively absorbed via the intranasal route, because the higher molecular weight PEG (over 2 kDa) limited intranasal absorption. Finally, in vivo hypoglycemic experiment showed that Lys²⁷-PEG(2k)-, Lys²⁷-PEG(5k)-Ex4 had significantly lower hypoglycemic efficacies than Lys²⁷-PEG(1k)-Ex4, probably because of their lower intrinsic bioactivities and intranasal absorptions. Taken together, our findings suggest that the site-specific conjugation of appropriately sized PEG (1 kDa) substitution onto peptides like Ex4 offers two advantages for deliveryvia the intranasal route, namely, increased stability and extended circulating half-life.

Pentaerythritol turns out to be an efficient soluble tetrapodal support permitting the traceless release of various biaryl compounds attached by a sulfonate linkage.

was obtained as a 60 : 40 mixture of geometric isomers that were not separable by common chromatographic methods. Fortunately, we observed that a careful recrystallizing process in 2-propanol facilitated the selective isolation of both isomers. Nuclear magnetic reso-nance (NMR) study showed that the initially recrystallized major product was (

Friction-type reinforcing members (FRMs) developed for the purpose of enhancing the wind-resistant performance of transmission towers are tested experimentally. The FRMs, in the middle of which slotted bolted connections (SBCs) are installed, are placed on the outside of tower legs, and provide additional damping and stiffness to the tower structure under bending deformations. Firstly, the SBCs used in the FRMs are tested for various frictional sliding interface conditions. Secondly, the FRMs are installed on a 1/2 scale plane tower substructure and cyclic loading tests are conducted. Energy dissipation capacity and effects from local deformations of the FRMs and joint slips are investigated. From the test results, remarkable energy dissipation capacity, reaching to the 2.4 times of that before the installation of the FRMs, is observed. However, the local deformation of the SBC and joint slip should be prevented for more reliable design of the FRMs.Copyright © 2008 by ASME

This study introduces the quantitative evaluation of the seismic performance of a building structure equipped with MR dampers by using real-time hybrid testing method (RT-HYTEM). A real-scaled 5-story building is used as the numerical substructure, and MR dampers corresponding to an experimental substructure is physically tested by using UTM. First, the force required to drive the displacement of the story, at which the MR damper is located, is measured from the load cell attached to UTM. Then, the measured force is returned to a control computer to calculate the response of the numerical substructure. Finally, the experimental substructure is excited by UTM with the calculated response of the numerical substructure. The RT-HYTEM implemented in this study is validated for that the real-time hybrid testing results obtained by application of sinusoidal and earthquake excitations and the corresponding analytical results obtained by using the Bouc-Wen model as the control force of the MR damper respect to input currents were in good agreement. Furthermore, semi-active control algorithms were applied to the MR damper. The comparison results of experimental and numerical responses demonstrated that using RT-HYTEM was more reasonable in semi-active devices such as MR dampers having strong nonlinearity.Copyright © 2008 by ASME

The accurate identification of the dynamic response characteristics of a building structure excited by input signals such as real earthquake or wind load is essential not only for the evaluation of the safety and serviceability of the building structure, but for the verification of an analytical model used in the seismic or wind design. In the field of system identification (SI) which constructs system matrices describing the accurate input/output relationship, it is critical that input should have enough energy to excite fundamental structural modes and a good quality of output containing structural information should be measured. In this study forced vibration testing which is important for correlating the mathematical model of a structure with the real one and for evaluating the performance of the real structure was implemented. There exist various techniques available for evaluating the seismic performance using dynamic and static measurements. In this paper, full scale forced vibration tests simulating earthquake response are implemented by using a hybrid mass damper. The finite element (FE) model of the structure was analytically constructed using ANSYS and the model was updated using the results experimentally measured by the forced vibration test. Pseudo-earthquake excitation tests showed that HMD induced floor responses coincided with the earthquake induced ones which was numerically calculated based on the updated FE model.Copyright © 2008 by ASME