Table Experiments Research Articles

Faktor-Faktor Kualitas Sumber Daya Manusia Terhadap Efektivitas Kerja Pegawai Pada Kantor Kelurahan Timbau Kecamatan Tenggarong

The research result, Y = 2,849 + 0,629X1 + 0,111X2 + 0,255X3. The three independent variable which resulted positive symbol declare that every addition of 1 (one) independent variable unit will increase the dependent variable.R number which resulted is 0,602, means correlation or relation between education and training variable, leadership wisdom and job dicipline with the effectiveness of employees job is significant because number 0,602 is upper 0,5 or approach 1 ( r = 1 ). R square number is 0,36 means 36 % job effectiveness is influenced by education and training variable, leadership wisdom and job dicipline however the rest 64% is influenced by variable, such as compensation, work motivation, leader’s behaviour etc.Hypothesis experiment is known F table score is 2,72, means F arithmetic > F table or 2,75 > 2,72. So that the second hypothesis which is asked estimated together there is positive and significant effect between the quality of human resource factors to the effectiveness civil servant’s work at Kelurahan Timbau office can be received because the correctness has been proved.T experiment is known the three variable produce t arithmetic experiment > from t table experiment to the work effectiveness. According to the first hypothesis result which is asked, there is positive and significant effect between the quality of human resource factors to the effectiveness civil servant’s work at Kelurahan Timbau office can be received because the correctness has been proved. Key Word : Human resource , Effectiveness

Soil Heating in Fire (SheFire): A model and measurement method for estimating soil heating and effects during wildland fires.

Fire has transformative effects on soil biological, chemical, and physical properties in terrestrial ecosystems around the world. While methods for estimating fire characteristics and associated effects aboveground have progressed in recent decades, there remain major challenges in characterizing soil heating and associated effects belowground. Overcoming these challenges is crucial for understanding how fire influences soil carbon storage, biogeochemical cycling, and ecosystem recovery. In this paper, we present a novel framework for characterizing belowground heating and effects. The framework includes (1) an open-source model to estimate fire-driven soil heating, cooling, and the biotic effects of heating across depths and over time (Soil Heating in Fire model; SheFire) and (2) a simple field method for recording soil temperatures at multiple depths using self-contained temperature sensor and data loggers (i.e., iButtons), installed along a wooden stake inserted into the soil (i.e., an iStake). The iStake overcomes many logistical challenges associated with obtaining temperature profiles using thermocouples. Heating measurements provide inputs to the SheFire model, and modeled soil heating can then be used to derive ecosystem response functions, such as heating effects on microorganisms and tissues. To validate SheFire estimates, we conducted a burn table experiment using iStakes to record temperatures that were in turn used to fit the SheFire model. We then compared SheFire predicted temperatures against measured temperatures at other soil depths. To benchmark iStake measurements against those recorded by thermocouples, we co-located both types of sensors in the burn table experiment. We found that SheFire demonstrated skill in interpolating and extrapolating soil temperatures, with the largest errors occurring at the shallowest depths. We also found that iButton sensors are comparable to thermocouples for recording soil temperatures during fires. Finally, we present a case study using iStakes and SheFire to estimate in situ soil heating during a prescribed fire and demonstrate how observed heating regimes would influence seed and tree root vascular cambium survival at different soil depths. This measurement-modeling framework provides a cutting-edge approach for describing soil temperature regimes (i.e., soil heating) through a soil profile and predicting biological responses.

How have Cretan rivers responded to late Holocene uplift? A multi‐millennial, multi‐catchment field experiment to evaluate the applicability of Schumm and Parker's (1973) complex response model

Abstract‘Complex response’ (Schumm, 1973, Geomorphic thresholds and complex response of drainage systems. In Morisawa, M. (ed.), Fluvial Geomorphology. Binghamton: New York State University Publications: 299‐310) describes situations in which a single event triggers a series of progressively damped morphological and sedimentary adjustments within a catchment. Schumm and Parker's (1973, Implications of complex response of drainage systems for Quaternary alluvial stratigraphy. Nature 243: 99–100) classic stream table experiment of drainage system development showed that one baselevel fall event could result in formation of two sets of paired river terraces that need not be related to additional external (e.g., climate) influences. Despite its enduring popularity in fluvial geomorphology, large‐scale and long‐term field evaluations of Schumm and Parker's complex response model are very limited. Here, we report on a multi‐millennial, multi‐catchment field experiment in south‐western Crete where a high‐magnitude earthquake (estimated magnitude 8.3–8.5) on 21 July 365 ce resulted in up to 9 m of instantaneous uplift over a land area exceeding 6000 km2. Geomorphological, sedimentological, and chronological investigations were used to investigate the erosional and depositional histories in three catchments with outlets uplifted by the 365 ce event. These catchments were compared with the Anapodaris catchment in south central Crete where baselevel was not significantly affected by the earthquake. Although all uplifted catchments experienced valley floor incision, this occurred hundreds of years after 365 ce during a period of wetter climate. The number and age of trunk stream incision and aggradation phases are similar in both uplifted and non‐uplifted catchments, indicating that river responses following the 365 ce uplift event have not followed complex response trajectories in the form documented by Schumm and Parker (1973). This finding highlights the need for rigorous evaluation of other catchment or river response concepts, including through the combined use of laboratory experimental results, field data, and geochronology. In an era of rapid environmental change, characterizing and anticipating catchment and river system response increasingly will depend on a healthy interplay between different investigative approaches.

Impact model and computational analysis of structural isolation layer deformation limitation with limiters

Hard-collision deformation limitation (HCDL) and soft collision deformation limitation (SCDL) with rigid or soft limiters to restrict the deformation of isolation layers are investigated analytically by three mechanical models. A complete model and two simplified models based on the contact element method are proposed and applied in two restricted base-isolated structures. A time history analysis and computational program in MATLAB is generated by the incremental method to calculate the dynamic response of HCDL and SCDL structures. A one-sixth scale base-isolated steel moment-resistant frame with special-designed limiters is created, and extensive shaking table experiments are conducted to validate the analysis program. The analytical program can accurately predict the dynamic performance of isolated structures with HCDL and SCDL. The results also reveal that contact stiffness is more sensitive than contact damping to the isolation layer deformation. However, the sensitivity decreases when the contact stiffness is higher than the isolation layer stiffness by one order of magnitude.

Effects of Guangzhou seasonal climate change on the development of Aedes albopictus and its susceptibility to DENV-2.

The susceptibility of Asian tiger mosquitoes to DENV-2 in different seasons was observed in simulated field environments as a reference to design dengue fever control strategies in Guangzhou. The life table experiments of mosquitoes in four seasons were carried out in the field. The susceptibility of Ae. albopictus to dengue virus was observed in both environments in Guangzhou in summer and winter. Ae. albopictus was infected with dengue virus by oral feeding. On day 7 and 14 after infection, the viral load in the head, ovary, and midgut of the mosquito was detected using real-time fluorescent quantitative PCR. Immune-associated gene expression in infected mosquitoes was performed using quantitative real-time reverse transcriptase PCR. The hatching rate and pupation rate of Ae. albopictus larvae in different seasons differed significantly. The winter hatching rate of larvae was lower than that in summer, and the incubation time was longer than in summer. In the winter field environment, Ae. albopictus still underwent basic growth and development processes. Mosquitoes in the simulated field environment were more susceptible to DENV-2 than those in the simulated laboratory environment. In the midgut, viral RNA levels on day 7 in summer were higher than those on day 7 in winter (F = 14.459, P = 0.01); ovarian viral RNA levels on day 7 in summer were higher than those on day 7 in winter (F = 8.656, P < 0.001), but there was no significant difference in the viral load at other time points (P > 0.05). Dicer-2 mRNA expression on day 7 in winter was 4.071 times than that on day 7 in summer: the viral load and Dicer-2 expression correlated moderately. Ae. albopictus could still develop and transmit dengue virus in winter in Guangzhou. Mosquitoes under simulated field conditions were more susceptible to DENV-2 than those under simulated laboratory conditions.

Rapid adaptation of Brachionus dorcas (Rotifera) to tetracycline antibiotic stress.

Although natural populations can rapidly adapt to selection pressures, the fitness consequences of selection are controversial. In this study, a selection experiment was conducted with replicate populations of Brachionus dorcas that were exposed to two sublethal concentrations (26.8 and 78.3mg/L) of oxytetracycline (OTC), followed by two common garden experiments (population growth and life table experiments). During the 102-day (approximately 36 asexual generations) selection experiment, a markedly increased growth rate but a significantly decreased mictic ratio over time in the populations exposed to OTC when compared to the control populations suggested that the former adapted to the selection pressures and that a trade-off exists between asexual and sexual reproduction. The high and stable population growth rates after 90 days of OTC selection illustrate an example of evolutionary rescue. After 102 days of selection, OTC-selected populations showed higher population growth rates than the control populations when exposed to OTC, indicating significantly increased tolerance. OTC-selected populations showed a lower average growth rate, longer average generation time and life expectancy at hatching, and higher average net reproduction rate and proportion of mictic offspring than the control populations in the absence of OTC, which indicate that OTC selection results in two fitness costs and three fitness gains and that the effect of OTC selection on fitness differs with the measured fitness variables. Both the evolutionary potential of populations under the stress of higher concentrations of OTC and the fitness costs and gains of selection in the absence of OTC indicate that past exposures to pollutants cannot be neglected when evaluating the effects of current stressors on natural populations.

Effect of pier height and support flexibility on seismic response of bridges including poundings

In conventional seismic design, bridges usually are assumed to be fixed to a rigid support. This assumption, however, does not correspond to the reality of bridges with shallow footings since they can rock in strong earthquakes. It has been recognised that several factors significantly affect the response of bridges with rocking footings, including support flexibility, pier height and pounding. Most studies so far have mainly focused on a single factor. This research aims to narrow the knowledge gap by investigating the combined effect of pier height, support condition and earthquake characteristics on bridges with rocking ability. A series of shake table experiments on a single-frame bridge with different pier heights and support conditions under hard, medium and soft soil excitations were carried out. The influence of support flexibility was examined by comparing the response of rocking bridges on rigid support with that on soil support. The result shows that regardless of the flexibility of the support, in the case of no pounding, it is beneficial to take rocking footing into account because the maximum bending moment at the pier support can be reduced. However, when pounding was considered, the combined effect can generate an even larger maximum bending moment than that of the fixed-base bridge.

Numerical Modeling and Shake Table Test for Seismic Response Evaluation of an Auxiliary Building in NPP with Reinforced Concrete Shear Wall

The dynamic responses of three storied auxiliary building of a nuclear power plant (NPP) constructed with a monolithic reinforced concrete shear wall are investigated in this study. The dynamic characterization is weighed through a shake table test and evaluated the efficiency of various structural modeling systems for evaluating seismic responses. The shear wall was subjected to a collaborative research round-robin analysis conducted by the Korea Atomic Energy Research Institute to forecast seismic responses of the auxiliary building in the NPP using a shake table test. The shake table test was performed with five different levels of intensity measures of the base excitation to obtain acceleration responses from different positions of the building in one horizontal direction (front-back). The main motivation of this study is to develop a nonlinear numerical model and examine the efficiency of various modeling approaches for evaluating the performance under seismic loading. Three numerical modeling approaches, i.e., multi-layer shell element modeling (MLSM), fiber beam-column element modeling (FBCM), and beam-truss element modeling (BTM), are generated to simulate the seismic response behaviors of the auxiliary building structure. Modal analysis, floor response spectra, acceleration amplification factor along with height, and story shear force of the building are compared as they are critical responses for evaluating the seismic vulnerability of the structure. The comparison shows that all the nonlinear numerical modeling approaches, i.e., MLSM, FBCM, and BTM, can predict the complex behavior of a shear wall system for low earthquake level, but for high earthquake level, MLSM shows better agreement with the shake table experiment. So, it is recommended to use MLSM modeling for nonlinear analysis with an earthquake intensity measure of 1 g or more.

Rocking Shallow Foundations on Geogrid-reinforced Ganga Sand Bed: An Experimental Study

ABSTRACT The efficiency of polyester and bamboo geogrids in reducing the seismic settlement of low-rise buildings has been investigated in this paper. A series of shake table experiments was carried out for this purpose. It was observed that the beneficial attributes of a rocking foundations in reducing the flexural deformation and column moment remained unchanged after inclusion of geogrids. However, the settlement, a primary adverse consequence of a rocking foundation, reduced significantly (as much as 70–75%). In a developing country like India, natural material-like bamboo threads combined with geo-polymers may be utilized for safe and sustainable seismic design.

A tuned liquid mass damper implemented in a deep liquid storage tank for seismic vibration control of short period structures

SummaryDeep liquid storage tanks cannot be implemented as tuned liquid damper (TLD) as the depth ratios often exceed the limit (0.3) for nonlinear sloshing and wave breaking. This study exploits the impulsive liquid mass to implement a tuned liquid mass damper (TLMD) by flexibly attaching the tank to the structure. The flexible mounting allows tuning of vibration of the impulsive mass to short period structures. The small, suboptimally tuned sloshing mass may also have minor contribute in dissipation. The performance of the TLMD is demonstrated by simulation and shake table experiments. The simulation involves solution of the governing equations for the structure‐TLMD system, in which the vibration of liquid is described by the Housner model. The optimal parameters for tuning are obtained through optimization. The dynamic response evaluation employs a suite of far field, recorded ground motions of varying hazard levels to demonstrate robustness. The simulation and the experiment results corroborate well. Comparative assessments with TMD and TLD with identical mass ratios show comparable efficiency. Given that the stored liquid is employed for the functional purpose (unlike the added mass in TMD), the proposed TLMD may be a preferred alternative to conventional tuned mass damper (TMD) or TLD.

Displacement based seismic assessment of base restrained retaining walls

The present work deals with assessment of earthquake-induced displacement of the base restrained retaining walls (RW’s). A detailed and rigorous finite element (FE) investigation has been carried out following the shaking table experiments on a scaled-down RW model. The FE simulations were performed by conducting several nonlinear time history analyses on a two-dimensional (2D) plane strain FE model of a prototype RW. The hardening and softening of backfill have been simulated by calibrating the Mohr Coulomb material model against the triaxial test results. Role of different backfill into the seismic performance of base restrained RW has also been investigated. It was observed that the cohesionless backfill has a slight influence on the earthquake induced displacement of base restrained RW’s. Amplification of horizontal acceleration in backfill has been observed with no direct correlation with the applied earthquake excitation. The understanding and findings based on shaking table experiment and FE simulations have been used for development of an analytical model for estimation of earthquake induced displacement of base restrained RW. The validity of proposed analytical model has also been examined against the shaking table experiment and FE simulation results.

Artificial Light Pollution with Different Wavelengths at Night Interferes with Development, Reproduction, and Antipredator Defenses of Daphnia magna.

Artificial light at night (ALAN) dramatically alters the natural daily cycle of light and may cause a suite of physiological and behavioral responses of freshwater crustacean Daphnia. Here, we conducted a life table experiment to investigate the effect of different wavelengths [white (L-L, 400-800 nm), red (R, 614 nm), green (G, 527 nm), and blue (B, 447 nm)] and flashing modes [three colors flash alternately (3-Flash), seven colors strobe alternately (7-Strobe)] of ALAN on the development, reproduction, and predator-induced defenses of Daphnia magna. The results showed that G inhibited the development of the body and tail spine of Daphnia at sexual maturity and decreased their reproduction. The 7-Strobe promoted Daphnia to develop a larger eye. There was an interaction between fish kairomones and ALAN, which intensified over time. ALAN enhanced the response of the relative tail spine length to fish kairomone at sexual maturity. In addition, L-L and R inhibited the body length of 10th instar D. magna in response to fish kairomone. Through the hierarchical cluster method, the 3-Flash and B are recommended as friendly artificial lighting to Daphnia. Our results highlight the interference effects of ALAN on Daphnia, which are helpful to assess the potential impact of light pollution on zooplankton.

Seismic Response of Magnetically Levitated House

This study explored the seismic response of a house supporting base sides with a polymeric displacement control material and by magnetically levitating the foundation base. In this paper, we explore the possibility and efficacy of a seismic-isolated detached house as described above from both a shaking table experiment of model and three-dimensional finite element analysis. The seismic-isolated model showed stable response and its acceleration response was significantly reduced compared to the base-fixed model in the shaking table test. Three-dimensional finite element analysis was possible to simulate the experimental results. In the seismic response analysis of a full-scale detached house, the seismic-isolated model showed response reduction and its residual displacement was smaller than that of the sliding-base isolation model.

Shaking Table Experiment on Seismic Performance of a Scaled-Down Arch Dam with Initial Crack

Seismic responses of cracked scaled-down arch dams were investigated by experiment on a shaking table. Two different curvature models (M1 and M2) were cast by using a plan concrete. Dams properties, including materials and dimensions, were carefully simulated. A significant earthquake magnitude with (7.7M) and water pressure were applied on the dam's models. Considering water and seismic loadings, the dynamic reactions of the arch dam's system were investigated. Both models showed crack overstresses or propagation on the dam's model as a result of seismic excitations. The arch dam with a higher degree of curvature was recorded 44 Mpa of stress evaluation which less by 30.7% of the arch dam with the lowest degree of curvature. The results indicated that raising the degree of curvature led to raising the dam's stability, earthquake resistance, less displacement, and less growth of tensile cracks.

Observations and challenges in simulating post-liquefaction settlements from centrifuge and shake table tests

Liquefaction-induced reconsolidation settlements occur as excess pore pressures generated during shaking dissipate and can lead to significant damage to overlying infrastructure. Designing resilient infrastructure in areas affected by liquefaction requires methods to predict these settlements for different soil types and boundary conditions. Simplified empirical models are commonly utilized to evaluate settlements but they exhibit several limitations that might hinder the accuracy of settlement predictions, including effects of partial drainage, thin layers, non-liquefiable crusts, or soil fabric. Numerical models can capture these effects but require proper calibration and validation. This study uses a numerical approach to simulate centrifuge and shake table experiments with free-field level, ground conditions and five different sands for evaluating reconsolidation settlements. The numerical platform FLAC and constitutive relationship PM4Sand are utilized. The necessity of soil-specific calibration of post-liquefaction stiffness and an excess pore pressure ratio dependent hydraulic conductivity to accurately model the observed pore pressures and settlements is analyzed. A new relationship between the increase in hydraulic conductivity due to liquefaction and grain size diameter is proposed. The numerical simulations are able to capture the general trends, but the bias in the results appears to be correlated with the grain size distribution of the tested soil.

Nonlinear substructuring control for simultaneous control of acceleration and displacement in shake table substructuring experiments

This paper reports the first application of nonlinear substructuring control (NLSC) to shake table experiments in which the table dynamics is significantly affected by the specimen. Substructuring experiments using a shake table require simultaneous control of acceleration and displacement of the table because it functions as both an actuation system and a part of the substructure in the experiments. NLSC was developed as an enhanced version of linear substructuring control (LSC), the basic method for the control of dynamically substructured system. This paper first describes the formulation of substructures for shake table experiments using a multiple-degree-of-freedom structure and NLSC design for the substructures. The stability analysis of NLSC, which has three controllers, becomes much more complicated, more frequently showing conditional stability than is observed in conventional experiments. To assess various conditionally stable systems, this paper proposes an equivalent approach that can systematically count encirclements of the critical point in Nyquist plots. In the stability analysis using the proposed approach, NLSC is more robust against parameter variations in the substructures than LSC. In addition, the error feedback controller in both LSC and NLSC enhances the robustness against the variations. This study numerically and experimentally examined control performances for shake table substructuring experiments involving nonlinear characteristics. In the examinations, NLSC achieved the expected displacement and acceleration control with stability and reasonable accuracy, whereas LSC could not. The error feedback controller design of NLSC was found to be essential for performing shake table substructuring experiments with severe nonlinear characteristics.

Effect of earthquake-induced transverse poundings on a 32 m span railway bridge isolated by friction pendulum bearings

To reduce the seismic force transmitted between piers and girders, friction pendulum bearings have been widely used in bridge structures. However, the bearings will lead to large relative displacements between the girder and the pier and thus increase the pounding potential of adjacent bridge structures. In the transverse direction, the girder movement can only be limited by shear keys. In this study, a series of shake table experiments were performed on a 1/6-scaled bridge model. To evaluate the consequences of poundings for isolated bridges, the wavelet transform (WT) is applied in addition to the fast Fourier transform (FFT). WT transform is used to capture the change in frequency content at the time of impact, while FFT is used to visualise the change in the frequency content of the entire response. Four different gap sizes and El-Centro earthquake with two different peak ground accelerations were considered. The results show that the selected gap size is relevant to the overall performance of the bridge.

Experimental Study on Seismic Instability of Pile-Supported Structure Considering Different Ground Conditions

The stability of pile-supported structures under earthquake loads involves complex dynamic soil–structure interaction (SSI). A series of large-scale shaking table experiments was performed to investigate the seismic performance and SSI of pile-supported structures considering different ground conditions. Lateral soil resistance and dynamic displacements of superstructures located in nonliquefiable and liquefiable sites as well as a rigid foundation were measured during shaking tests. The measured responses were analyzed to investigate the P-Δ effect on structural stability. It was observed that the soil lateral resistance to the pile cap at the nonliquefiable site was large and represented the main component of the lateral bearing capacity resisting structure overturning. On the other hand, the lateral resistance of liquefied soil on piles was insignificant and the lateral bearing capacity was derived primarily from soil resistance to pile cap. The analysis of the measured dynamic displacements demonstrated that the seismic instability of the structure was mainly due to the P-Δ effect caused by the rotation of the foundation, especially in liquefied sites. In addition, comparison with the results of base shears and bending moments with the rigid base assumption allows for an in-depth discussion of the effect of SSI on structural seismic design.

Seismic response of helical pile groups from shake table experiments

This paper presents and discusses the measured responses of single and grouped helical piles to strong ground motions during a large-scale shake table testing program. The effects of earthquake characteristics (i.e., intensity and frequency content) on the seismic performance of single and grouped helical piles are evaluated from the measured responses. In addition, the performance characteristics of helical pile groups are discussed in terms of the interaction between piles within a group and the contributions of vertical and lateral stiffness of individual piles to the rocking stiffness and the overall capacity of the pile group. Furthermore, the effect of pile head connection to the pile cap (fixed or pinned) on the pile group's response is evaluated and the responses of fixed pile groups (2-bolts connection) and pinned pile groups (1-bolt connection) are compared. Finally, the behaviour of a single pile and a pile within a group is compared in terms of their normalized responses.

Maximum drift estimation based on only one accelerometer for damaged shear structures with unknown parameters

This paper presents a method to estimate the maximum inter-story drift and relative displacement time history of multi-degree-of-freedom (MDOF) shear structures underground-motion excitation by using only one accelerometer installed on a floor when the structures are damaged during the event and hence modal parameters change and become unavailable. First, the absolute acceleration and relative displacement are formulated in modal coordinates and a state-space expression is derived. Then, a scheme to determine the unknown natural frequencies of the damaged structure is devised with the help of the genetic algorithm (GA) and a reasonably chosen fitness function, and the mode shapes are updated by solving a set of nonlinear equations with respect to each group of frequency variables in the GA. The applicability of this method was studied in numerical simulations that examined the effect of the extent of damage to the structure and the selection of the lower bound of the GA variables. Further simulations were conducted to investigate the modal truncation error and robustness against measurement noise of the proposed approach. Finally, the method was validated in a shake table experiment. The results indicate that the time history of the relative displacement and maximum inter-story drift can be accurately estimated in the case of a significant reduction in structural stiffness and a large search range of GA variables. The results also show the method is robust against noise and performs well even when only the lower modes are included in the model.