Civil Engineering

Automatic short answer grading (ASAG) has become part of natural language processing problems. Modern ASAG systems start with natural language preprocessing and end with grading. Researchers started experimenting with machine learning in the preprocessing stage and deep learning techniques in automatic grading for English. However, little research is available on automatic grading for Arabic. Datasets are important to ASAG, and limited datasets are available in Arabic. In this research, we have collected a set of questions, answers, and associated grades in Arabic. We have made this dataset publicly available. We have extended to Arabic the solutions used for English ASAG. We have tested how automatic grading works on answers in Arabic provided by schoolchildren in 6th grade in the context of serious games. We found out those schoolchildren providing answers that are 5.6 words long on average. On such answers, deep learning-based grading has achieved high accuracy even with limited training data. We have tested three different recurrent neural networks for grading. With a transformer, we have achieved an accuracy of 95.67%. ASAG for school children will help detect children with learning problems early. When detected early, teachers can solve learning problems easily. This is the main purpose of this research.

In this paper we describe a procedure for disaggregating agricultural land use choices at NUTS 2 level to about 18.000 homogeneous spatial units completely covering the usable agricultural area of the EU. The disaggregation procedure uses 40.000 sampling points and aggregate data from administrative regions and requires two steps: First, we employ crop specific, spatial binary choice models to regress land use decisions on local natural conditions (soil, relief, climate) based on the sample information. Results allow predicting crop shares in each spatial unit. Second, consistency with data from administrative regions is achieved by maximising the posterior density of crop shares subject to aggregating equations using the forecast distributions as prior information. Comparison with actual crop shares shows the validity of the procedure.

Flooding is a natural occurrence hazardous to people and properties and produces environmental and economic losses, especially in flood-prone areas. This study will be used to assess flood risk in the Bangko and Masjid watersheds. To analyze it, flood hazard mapping is arranged by slope, land cover, elevation, rainfall, buffer zone, and soil type, which is done with the help of a Geographic Information System (GIS), specifically QuantumGIS (QGIS). This system tool assesses each variable utilizing satellite spatial data and categorizes the vulnerability being very high, high, medium, low, and very low. Each map arrangement value is combined using an overlay value to determine the flood susceptibility. According to the mapping results, the Bangko and Masjid watersheds are highly vulnerable to flooding. Based on the results of the mapping, in the Bangko watershed 61% of the total area is vulnerable to flooding, and 20% has high to very high vulnerability, while in the Mosque watershed ...

Penetration into concrete is an important problem that attracted many researches who developed analytical models and numerical solutions. Most of the advanced methods account for the material properties through their constitutive equations, combined from the failure envelope and the equation of state. These properties are rarely available in many cases, and in different experimental reports it is missing. For lack of any other option, analysts borrow available equations that were developed for other concrete types, with the doubt of their suitability. In a limited number of tests, instrumented projectiles are used and the deceleration time history is recorded. Rarely, the constitutive properties are also provided and analysis can be conducted. Otherwise, analysis cannot be carried out and prediction and validation of the recorded deceleration curve cannot be conducted. The present article refers to such instrumented tests where the constitutive properties are not available. It aims at unveiling the relationship between the deceleration curve and the constitutive properties and at solving, for the first time, the inverse problem of a penetration problem in order to retrieve major constitutive equation parameters from the acceleration time-history record. The major new feature of the present article is identification of the failure envelope parameters in the Mohr-Coulomb form as well as the parameters of the Shock Hugoniot equation of state for which procedures have been developed. The present approach allows to retrieve required information regarding the equation of state and failure envelope from a single instrumented experiment that provides the projectile deceleration time-history record. It is shown that the retrieved parameters of the failure envelope and the equation of state are in good agreement with reported constitutive parameters that are based on experimental data. The retrieved data allow to carry out penetration time-history predictions of different projectiles at different impact velocities on the same concrete.

This study focuses on a RC building with flat slabs that were designed according to current standards. A scenario of a slab with failed connections that is detached from its supporting columns and is falling downward is considered, and the impact results with the slab underneath are assessed. The suitability of the standards design criteria to provide safe design against impact loading is evaluated. It was found that larger span slabs experience heavier damage. Falling from a floor height and from a quarter floor height are analyzed and the damage results of these impacts are examined. At the lower impact velocity, the concrete slab surrounding the column undergoes major damage and shear deformations; In the case of a relatively short span slab, the rebars undergo large plastic deformations and almost reach the ultimate strain, such that a slightly higher impact velocity would cause rebars fracture and total failure of the slab-column connection. In the case of high impact velocity, the concrete in the slab around the column is fully crashed and the longitudinal and the bent up rebars are ruptured. The yield of the rebars occurs within a few milliseconds. During this extremely short time the impacted slab hardly starts developing its downward displacement. The impacted slab responds like a rigid body with severe damage concentration at the slab-column connection region. Different parameters affecting the slabs dynamic response are examined, and new insight is gained on the complex impact response of flat RC slabs. This study finds that the current design standards that are based on static loading considerations do not provide resilience to flat slab connections that are subjected to impact loading and therefore cannot prevent a progressive collapse scenario.

Acceleration time histories of earthquake events are typically measured in seismic stations that are placed close to the soil top surface. These acceleration records are often used as input data for seismic analysis. It may be used for base excitation in seismic analysis of above ground structures with shallow foundations.. However it may not be used for seismic analysis of underground structures, or even for above ground buildings with deep foundations and several underground stories. The required base excitation data of the latter should have been measured below the top surface, at a level that may be determined according to the specific analyzed building geometry or at the bedrock below. If the acceleration time history at the bedrock would have been known, the seismic wave propagation through the soil medium, from the bedrock towards the top surface, could have been carried out and the base excitation of the buried structure could be determined. Since there is no data on the acceleration time history at the bedrock, and the only given data is the acceleration records at the top surface, the goal of this paper is to provide an exact reverse analysis procedure to determine the unknown acceleration time history at the bedrock that would exactly produce the measured acceleration time history at the top surface. Once this goal is achieved, seismic analysis of buried structures may be carried out with the determined acceleration record at the bedrock as input. This paper presents an analytical exact solution of the inverse problem for determination of the acceleration, velocity and displacement time histories at the bedrock base of a layered geological medium that are compatible with the given acceleration record at the soil top surface. This new proposed method is based on analytical solutions of the initial-boundary value problems of the linear wave equation in the case of a layered medium. The relationship between waves in one layer and waves in another adjacent layer is derived considering the continuity of stresses and displacements at the common interface between the layers. The efficiency and accuracy of the proposed method is demonstrated through several examples involving the nonstationary response of the free surface. The case of the San Fernando Earthquake is studied. Excellent agreement is achieved between the recorded free surface time history and the reconstructed signal. This excellent agreement is obtained due to the exact analytical method used in deriving the inverse problem solution. This exact analytical method allows one to obtain an acceleration (velocity/displacement) distribution along all the layers at any time.

This article analyzes the fundamental question of the mechanical properties representation in penetration analysis and its effect on the calculated results. Penetration analysis into a concrete target with a specified uniaxial compressive strength was carried out using different material models appearing in software libraries. These models determine the specific material equation of state and shear strength envelope related to the concrete uniaxial compressive strength. Different results were obtained for the same concrete strength. This proves that the unconfined compressive strength is not the governing parameter which determines the projectile penetration characteristics and that a large variation of results is obtained from different models. Analysis was then carried out on a case with documented constitutive properties of a concrete target that was penetrated by an instrumented projectile. The predicted penetration depth and the projectile deceleration time history were compared with the measured data, and very good correspondence was obtained. This proved that the specific properties of the penetrated medium should be incorporated in the analysis to properly predict the penetration event. The study then examined the commonly used approximation of a linearized equation of state and a linear Mohr-Coulomb model, replacing the true nonlinear equations of state and the true non-linear shear strength dependence, and the linearized relationships' effect on the analyzed results was assessed. A detailed study of the solution sensitivity to different parameters of the Mohr-Coulomb relationship then followed, and its effect on different penetration parameters (nose embedment duration, nose embedment velocity, penetration depth, peak deceleration, quasi-static deceleration) has been examined, to demonstrate how a perturbation in assumed concrete properties affects the solution of the penetration problem. The article illuminates the role of the constitutive equations on penetration analysis and the importance of the proper selection of the representative expressions and of their approximations.

A parameter analysis is performed on an analytical penetration model which has been recently developed. Figures are plotted to show how the disturbed zone size, parameters of displacement and stress fields and dynamic section pressure are dependent on soil compressibility, shear strength and mass density. Main results are presented and discussed.

This study presents a solution for the dynamic response of a porous saturated medium to a harmonic motion of a rigid inclusion where an elastic type intermediate layer is located at the interface. The problem has been solved using the Neumann series which terms are obtained by means of recurrence relationships of simple iteration type. To perform regularization we consider every singular integral as an integral in sense of finite part by Hadamard. A modified Shanks transform was used to accelerate the series convergence. The method allows avoid the solution of large system of the linear algebraic equations with densely filled matrix. However, for problems with complicate boundary, which includes segments with large curvature, the requested number of series members sharply increases. The approach is valid for problems which potential satisfied to the Hölder-Lipschitz condition of the first order. Using the proposed approach the problem of a linear harmonic motion of the circular inclusion was investigated and the effect of the frequency on the contact stresses has been studied. It was found that for this specific example, when the vibration frequency increases the maxima of both contact normal stress and porous pressure decrease, while the maximum of the contact shear stress remains almost unchanged.

Static testing of glass plates has shown a pronounced distribution in the plate strength. The origin of fracture location along the plate span, the corresponding critical tensile stress and the size of the critical flaw at the origin of fracture are failure characteristics of major importance. This paper provides data and insight into parameters influencing these failure characteristics through laboratory testing and analysis of soda lime glass, to find a rationale behind the observed disorder of their magnitudes and distributions. A recent stochastic model for glass plate analysis is implemented to predict the magnitudes and distributions of the failure characteristics, and to compare these with laboratory tests. The model provides good predictions of the distributions and magnitudes of the failure characteristics and sheds light on glass plate behaviour. It demonstrates that there are mechanics-based explanations to the wide scatter of experimental results and to the apparent disorder in glass behaviour.

This paper presents results of the first stage of an experimental research program on the pounding response of adjacent concrete structures during earthquake. It shows experimental results for longitudinal impact of concrete rods. The impact of concrete to concrete surfaces of the rods was studied and the coefficient of restitution was experimentally determined. Acceleration time histories were recorded and characteristics of the impact pulse was determined. The study was extended to include filling materials that had been placed in the joint between the impacting concrete surfaces to study their effect on the impact.

The elasto-plastic theory of a shallow two bar truss is developed. The behavior of this structural system under tension loading or compression loading is formulated, as well as for reversal loading, where the structure undergoes loading, unloading and reloading. The simple straightforward expressions enable one to correlate the external work to the central displacement and follow the elasto-plastic stresses and strains in the bars along the loading history.

Purpose -Dams require high-volume of construction materials and operations over the life cycle. This paper aims to select a proper type of dam structure that can significantly contribute to the sustainability of dam projects. Design/methodology/approach -This research proposes a complementary fuel consumption and carbon dioxide (CO 2 ) emission assessment method for the alternate dam structure types to assist decisionmakers in selecting sustainable choices. Related equations are developed for two common earthen and rockfill dam structures types in Iran. These equations are then successfully applied to two real dam project cases where the significance of the achieved results are assessed and discussed. Findings -The achieved results of the case studies demonstrate a high deviation of up to 41.3% in CO 2 emissions comparing alternate dam structure scenarios of earthen and rock-fill dam structures. This high deviation represents an important potential for CO 2 emission reduction considering the high volume of the emission in large dam projects. Originality/value -The life cycle emission assessment of the alternate dam structures, proposed in this research as a novel complementary factor, can be used in the decision-making process of dam projects. The results in this research identify high potential sustainability improvement of dam projects as a result of the proposed method.

PurposeDams require high-volume of construction materials and operations over the life cycle. This paper aims to select a proper type of dam structure that can significantly contribute to the sustainability of dam projects.Design/methodology/approachThis research proposes a complementary fuel consumption and carbon dioxide (CO2) emission assessment method for the alternate dam structure types to assist decision-makers in selecting sustainable choices. Related equations are developed for two common earthen and rock-fill dam structures types in Iran. These equations are then successfully applied to two real dam project cases where the significance of the achieved results are assessed and discussed.FindingsThe achieved results of the case studies demonstrate a high deviation of up to 41.3% in CO2emissions comparing alternate dam structure scenarios of earthen and rock-fill dam structures. This high deviation represents an important potential for CO2emission reduction considering the hi...

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A welded steel moment-frame building is used to assess performancebased engineering guidelines. The full-scale four-story building was shaken to collapse on the E-Defense shake table in Japan. The collapse mode was a side-sway mechanism in the first story, which occurred in spite of a strongcolumn and weak-beam design. Computer analyses were conducted to simulate the building response during the experiment. The building was then evaluated using the Seismic Rehabilitation of Existing Buildings (ASCE-41) and Seismic Evaluation and Upgrade Criteria for Existing Welded Steel for the collapse prevention performance level via linear and nonlinear procedures. The guidelines had mixed results regarding the characterization of collapse, and no single approach was superior. They mostly erred on the safe side by predicting collapse at shaking intensities less than that in the experiment. Recommendations are made for guideline improvements.

The present statistical models used for forecasting cannot effectively handle uncertainty and instability nature of foreign exchange data. In this work, an artificial neural network foreign exchange rate forecasting model (AFERFM) was designed for foreign exchange rate forecasting to correct some of these problems. The design was divided into two phases, namely: training and forecasting. In the training phase, back propagation algorithm was used to train the foreign exchange rates and learn how to approximate input. Sigmoid Activation Function (SAF) was used to transform the input into a standard range [0, 1]. The learning weights were randomly assigned in the range [-0.1, 0.1] to obtain the output consistent with the training. SAF was depicted using a hyperbolic tangent in order to increase the learning rate and make learning efficient. Feed forward Network was used to improve the efficiency of the back propagation. Multilayer Perceptron Network was designed for forecasting. The datasets from oanda website were used as input in the back propagation for the evaluation and forecasting of foreign exchange rates. The design was implemented using matlab7.6 and visual studio because of their supports for implementing forecasting system. The system was tested using mean square error and standard deviation with learning rate of 0.10, an input layer, 3 hidden layers and an output layer. The best known related work, Hidden Markov foreign exchange rate forecasting model (HFERFM) showed an accuracy of 69.9% as against 81.2% accuracy of AFERFM. This shows that the new approach provided an improved technique for carrying out foreign exchange rate forecasting.

Phosphate treatments for conservation of stone have provided so far encouraging results in laboratory studies, as they exhibit good effectiveness, compatibility and durability to accelerated weathering tests. However, limited data are available about their long-term performance in real environment. Here, a systematic evaluation of phosphate consolidants after prolonged exposure in the field is reported for the first time. Naturally weathered marble specimens and a XVII century marble sculpture located in the Park of the Royal Palace in Versailles were treated by various formulations of the phosphate consolidant. Their conservation state was assessed before treatment by non-destructive methods (ultrasounds, color measurement, water absorption) and, in the case of the specimens, also by slightly destructive tests (SEM, FT-IR, MIP, IC). The conservation state of the specimens and the sculpture was further assessed right after treatment and then periodically monitored during exposure in...

Compressed sensing is a signal compression technique with very remarkable properties. Among them, maybe the most salient one is its ability of overcoming the Shannon-Nyquist sampling theorem. In other words, it is able to reconstruct a signal at less than 2Q samplings per second, where Q stands for the highest frequency content of the signal. This property has, however, important applications in the field of computational mechanics, as we analyze in this paper. We consider a wide variety of applications, such as model order reduction, manifold learning, data-driven applications and nonlinear dimensionality reduction. Examples are provided for all of them that show the potentialities of compressed sensing in terms of CPU savings in the field of computational mechanics. Compressed sensing • Model order reduction • Manifold learning • Nonlinear dimensionality reduction 1 Introduction Model Order Reduction (MOR) is acquiring an utmost importance for simulation-based engineering. These techniques allow solving efficiently complex mathematical models, thanks to the use of adapted approximation bases to describe their solutions. Among the numerous existing B E. Cueto

Handbook developed by the U.S. Environmental Protection Agency. The linear programming model is used to maximize net farm revenue using optimal combinations of crop rotations and tillage practices for each region of the United States given natural resource constraints. The LEACH handbook is used to determine the relative potential for pesticides to leach below the root zone for different soil types, hydrologic conditions, pesticides used, and tillage practices. The results indicate that imposing a surface water quality erosion constraint aimed at reducing sediment concentrations results in a larger decrease in farm income than imposing a uniform 5 ton per acre per year erosion constraint. Both constraints could result in regional improvement in ground water quality in some regions of the country while decreasing ground water quality in other regions.

The complete evaluation of the offsite effects of national policies or programs that affect levels of agricultural nonpoint source pollution requires linking extensive water quality changes to changes in recreational activity. A sequential decision model is specified to describe an individual's decisions about fishing. A participation model for recreational fishing that includes a water quality index reflecting regional water quality is developed and estimated as a logit model with national level data. A visitation model for those who decide to fish that also includes the water quality index is estimated using ordinary least squares. The water quality index is found to be significant in the participation model but not in the visitation model. Together, the two models provide a means of estimating how changes in water quality might influence the number of recreation days devoted to fishing. The model is used to estimate changes in fishing participation for the Conservation Reserve Program. WATER QUALITY IMPACTS ON RECREATIONAL FISHING Benefits to water-based recreation are one aspect of the offsite benefits from national soil conservation programs or other agricultural programs or policies that reduce agricultural nonpoint source pollution. Studies have indicated that water pollution damages to recreation are substantial and that large benefits could result from improving water quality [Freeman, 1982; Heintz et al., 1976; Unger, 1975; Feenberg and Mills, 1980]. If reducing agricultural sources of pollution can substantially improve overall water quality, then sizable benefits in terms of improved recreational opportunities can be gained. In this paper a model for estimating recreational fishing benefits from a national agricultural conservation program is developed. A water quality index representing regional water quality is used to drive changes in demand for fishing. The resulting model was used to estimate changes in fishing participation brought about by the Conservation Reserve Program. Decisions about agricultural production at both the micro and macro levels can influence water quality. At the farm level, farmers can choose crop management, tillage, soil conservation, and chemical management techniques. Their choices affect the amounts of sediments and chemicals washing off the land and into water resources. Of interest here are the national policy decisions that can influence the production decisions of a large percentage of the nation's farmers. Policies include conservation policies but also price support and acreage reduction programs. Such programs or policies can have a substantial impact on national water quality by influencing acreage in production, intensity of production, and degree of conservation. Assessing the offsite water quality impacts of such national policies requires some way of linking water quality to This paper is not subject to U.S. copyright. Published in 1991 by the American Geophysical Union. Paper number 91 WR00798. recreational behavior at the national level. A site-by-site approach would be extremely difficult, since national policies or programs influence water quality in many areas simultaneously. Also, the number of site studies required to analyze such changes would be prohibitively large. Even multisite or regional recreation visitation models such as those used by Sutherland [1982], Morey [1981], and Donnelly et aI. [!985] would be extremely cumbersome to use for a truly national policy analysis. Alternatively, a national model can be developed that does not rely on site data. The primary problem in estimating a national model is the availability of the necessary data.

An evaluation of the intermedia movement of pesticides applied under various land management systems already in place, or to be implemented, under the Conservation Reserve and Conservation Compliance programs is presented. The simulation modeling approach followed in this analysis consists of a mathematical programming model and leaching/surface runoff, Pesticide Root Zone Model (PRZM) models. Special care was taken to ensure that the physical model was sensitive to the chemical characteristics of individual pesticides and the important physical changes brought about by different agricultural practices. Results show that, although these programs as now planned, increase farm income and achieve soil conservation goals, they may adversely affect ground water quality. Also, depending on soil and location characteristics, there are tradeoffs between surface and ground water quality implications. Hence, if these programs are to address water quality problems, the recommended practices must be evaluated for their impact on water quality, particularly in potentially vulnerable areas.

ABSTRACT: Many water systems in small cities and rural areas throughout the United States are facing water quality and supply problems. These problems are typically not the result of an unexpected event, but are the result of growth trends or decreasing water quality experienced over several years. This analysis uses the contingent valuation and benefit transfer methods to evaluate the willingness to pay for a rural water system in northcentral Montana. Both of the procedures resulted in similar values, ranging from about $4.05 to $7.50 per household per month for urban residents and $5.40 to $11.50 per household per month for rural residents, which is equal to 11 percent to 23 percent of current average water costs. The willingness to pay estimates do not include non‐household water users. This analysis shows that useful planning information can be obtained from relatively inexpensive contingent valuation mail survey data and the benefit transfer method as long as the limitations o...

ABSTRACT: An evaluation of the intermedia movement of pesticides applied under various land management systems already in place, or to be implemented, under the Conservation Reserve and Conservation Compliance programs is presented. The simulation modeling approach followed in this analysis consists of a mathematical programming model and leaching/surface runoff, Pesticide Root Zone Model (PRZM) models. Special care was taken to ensure that the physical model was sensitive to the chemical characteristics of individual pesticides and the important physical changes brought about by different agricultural practices. Results show that, although these programs as now planned, increase farm income and achieve soil conservation goals, they may adversely affect ground water quality. Also, depending on soil and location characteristics, there are tradeoffs between surface and ground water quality implications. Hence, if these programs are to address water quality problems, the recommended pr...

The complete evaluation of the offsite effects of national policies or programs that affect levels of agricultural nonpoint source pollution requires linking extensive water quality changes to changes in recreational activity. A sequential decision model is specified to describe an individual's decisions about fishing. A participation model for recreational fishing that includes a water quality index reflecting regional water quality is developed and estimated as a logit model with national level data. A visitation model for those who decide to fish that also includes the water quality index is estimated using ordinary least squares. The water quality index is found to be significant in the participation model but not in the visitation model. Together, the two models provide a means of estimating how changes in water quality might influence the number of recreation days devoted to fishing. The model is used to estimate changes in fishing participation for the Conservation Reserv...

This analysis evaluates the extent to which water quality influences the cost of supplying domestic water and the extent to which finished water quality affects household water demand from price impacts. The water demand and cost models are based on nationwide data for individual systems collected by the American Water Works Association [1996]. The water cost model estimated in this analysis indicates that factors such as the size of the water supply system, the population density of the service area, the source of water supplies, and water quality all significantly affect the cost per unit of water delivered. The water use model indicates water demand is influenced significantly by household income, household size, temperature, precipitation, the price of water, and finished water quality. Combining the results of the models allows an analyst to evaluate the full impacts of water quality benefits on municipal water supplies.

ABSTRACT: The potential surface water and ground water quality tradeoff implications from the nonpoint source provisions of the 1987 Water Quality Act are investigated in this paper using a national linear programming model developed at Iowa State University and modified by the Economic Research Service and the Leaching Evaluation of Agricultural Chemicals (LEACH) Handbook developed by the U.S. Environmental Protection Agency. The linear programming model is used to maximize net farm revenue using optimal combinations of crop rotations and tillage practices for each region of the United States given natural resource constraints. The LEACH handbook is used to determine the relative potential for pesticides to leach below the root zone for different soil types, hydrologic conditions, pesticides used, and tillage practices. The results indicate that imposing a surface water quality erosion constraint aimed at reducing sediment concentrations results in a larger decrease in farm income ...

Advanced oxidation processes utilizing both UV/H 2 O 2 and photo-Fenton UV/H 2 O 2 /Fe +3 systems were investigated using pilot-scale experiments for the degradation and mineralization of 4-chlorophenol (4-CP). The experiments were conducted by using a photoreactor, which consists of three UV lamps fixed in staggered form. Three baffles were fixed vertically at the reactor side walls. These baffles reduce the presence of low radiation zones near the reactor walls. The study shows that the photo-Fenton process was the most effective treatment process under acidic conditions pH = 3, and produced a higher rate of degradation of 4-CP at a very short irradiation time. The reaction was found to follow the first order through both systems. A colored solution of benzoquinone can be observed through the first 5 min of irradiation time for the UV/H 2 O 2 system when a low concentration (0.01 mol/L) of H 2 O 2 was used. The colored solution of benzoquinone can also be observed through the first 5 min for the UV/ H 2 O 2 /Fe +3 system at a high concentration (100 ppm) of 4-CP. The experimental results show that the optimum reagents for complete degradation of 4-CP (50 ppm) were H 2 O 2 = 0.005 mol/ L, Fe +3 = 0.16 Â 10 À3 mol/L under acidic conditions (pH = 3), and irradiation time of 15 min for the UV/H 2 O 2 /Fe +3 system with a molar ratio of H 2 O 2 /Fe +3 /4-CP equals 13/0.4/1.

As a key component of global change, dam‐induced sediment reduction occurs in large rivers worldwide, which has profound implications on the fluvial systems. However, the systematic change of suspended sediment concentration (SSC) and its dynamic processes are not well known. We summarize typical SSC changes and propose a new sediment modeling framework for heavily dammed fluvial systems with the Changjiang (Yangtze River) as a background. We find that the fluvial SSC has declined by an order of magnitude, i.e., from ∼1.0 to ∼0.1 kg/m3, and even to ∼0.01 kg/m3 locally. The SSC distribution pattern along the mainstream has changed remarkably, with the sediment source/sink being partially reversed. Downstream of the Three Gorges Dam, the SSC recovery capacity gradually decreases with the sediment erosion quantity accumulated over time, and the SSC contribution rate of a linked large lake (Dongting) will change from negative (ca. −39%) to positive (ca. 17%), in the coming decades.

Water saving technologies are important for sustainable agriculture and forestry. Recent research indicates that the plant itself may alternate between several natural water sources to survive drought. Therefore, a key issue is how to establish the boundaries of hydrological conditions important for non-stressed tree growth. The smart decision might be to ask the plant itself. Sap flow represents a suitable language to such a talk: it gives long-term automatic records of plant responses to environmental changes. In this work we illustrate how root sap flow can be used to provide information on the thresholds for two sources of tree root water uptake, superficial soil water and groundwater. With this knowledge, a threshold diagram can be constructed which is species and site specific. Such a diagram may help managers of rain fed plantations to follow the current hydrological conditions and apply irrigation as a preventive treatment to avoid growth loss and tree mortality.

Symmetrical temperature difference also known as the sap flow index (SFI) forms the basis of the Heat Field Deformation sap flow measurement and is simultaneously collected whilst measuring the sap flow. SFI can also be measured by any sap flow method applying internal continuous heating through the additional installation of an axial differential thermocouple equidistantly around a heater. In earlier research on apple trees SFI was found to be an informative parameter for tree physiological studies, namely for assessing the contribution of stem water storage to daily transpiration. The studies presented in this work are based on the comparative monitoring of SFI and diameter in stems of different species (Pseudotsuga menziesii, Picea omorika, Pinus sylvestris) and tree sizes. The ability of SFI to follow the patterns of daily stem water storage use was empirically confirmed by our data. Additionally, as the HFD multipointsensors can measure sap flow at several stem sapwood depths, ...

Water is one of the major environmental factors limiting plant growth and survival in the Mediterranean region. Quercus suber L. woodlands occupy vast areas in the Iberian Peninsula, frequently under shallow water table conditions. The relative magnitude of soil and groundwater uptake to supply transpiration is not easy to evaluate under these circumstances. We recently developed a conceptual framework for the functioning of the root system in Q. suber that simulates well tree transpiration, based on two types of root behaviour: shallow connected and deep connected. Although this significantly improved knowledge on the functional traits of Mediterranean Q. suber, the approach has the limitation of requiring root sap flow data, which are seldom available. In this work, we present alternative methodologies to assess if trees are connected to groundwater and to estimate the soil and groundwater contributions to tree transpiration. We provide evidence on the tree unrestricted access to groundwater solely based on meteorological, stem sap flow and leaf water potential data. Using a soil mass balance approach, we estimated the yearly soil and groundwater contributions to tree transpiration: 69.7% and 30.3%, respectively. Groundwater uptake became dominant in the dry summer: 73.2% of tree transpiration. Results reproduce extremely well those derived from root modelling. Because of its simplicity both in formulation and data requirements, our approach is potentially liable to be adapted to other groundwaterdependent Mediterranean oak sites, where interactions between land use and water resources may be relevant.

The study focuses on the combination of two numerical approaches that are typically not used together in this manner. The first is a well-established partitioned fluid-structure interaction (FSI) simulation methodology relying on a finite-volume fluid solver for curvilinear, block-structured, body-fitted grids written in the Arbitrary Lagrangian-Eulerian (ALE) formulation, and a finite-element solver for the structural analysis. The second approach is an immersed boundary (IB) method employing a continuous and direct forcing strategy. The IB method, often applied to Cartesian grids, is also referred to as an approach to simulate fluid-structure interactions. In this study, both methods are combined to exploit their respective advantages in simulating a complex flow problem. The coupled FSI problem involves the interaction of a thin, flexible structure deforming under the dynamic load of a wind gust (task 1). The gust itself is generated by an artificial wind gust generator, which includes a paddle that partially obstructs the wind tunnel's outlet, thereby defining an FSI problem of its own (task 2). For task 1, the classical partitioned ALE approach is employed, while the IB method is more appropriate for task 2. Using available experimental measurement data for both the fluid flow and the structural deformation, the combined simulation framework is first validated for the case without gust. In a second step, the more challenging FSI problem of discrete gusts impacting the T-structure is thoroughly analyzed and the predicted data are compared with the available measurement data. For both cases without and with gusts, a very good agreement between simulation and experiment is achieved, which justifies the chosen approach.

Mixed mode I/II fracture criterion based on strain energy density theory is presented for failure investigation of cracked composite materials. Crack is assumed to occur along the fibers in a highly orthotropic body. A new definition for fracture toughness of crack tip damage zone is proposed and employed to include the effects of dissipated energy due to formation of considerable fracture process zone. As crack propagation occurs between fibers in the isotropic matrix, reinforcement isotropic solid model is employed as a superior material model. Elastic and fracture properties of damage zone are characterized as a function of undamaged matrix properties and micro-crack density. Center notched disk tension (CNDT) specimen is introduced and employed for fracture tests. Comparison of the fracture limit curves with experimental data proves the capability of the new proposed mixed mode fracture criterion for fracture investigation of orthotropic materials.

Mixed mode I/II fracture criterion based on strain energy density theory is presented for failure investigation of cracked composite materials. Crack is assumed to occur along the fibers in a highly orthotropic body. A new definition for fracture toughness of crack tip damage zone is proposed and employed to include the effects of dissipated energy due to formation of considerable fracture process zone. As crack propagation occurs between fibers in the isotropic matrix, reinforcement isotropic solid model is employed as a superior material model. Elastic and fracture properties of damage zone are characterized as a function of undamaged matrix properties and micro-crack density. Center notched disk tension (CNDT) specimen is introduced and employed for fracture tests. Comparison of the fracture limit curves with experimental data proves the capability of the new proposed mixed mode fracture criterion for fracture investigation of orthotropic materials.

The Karhunen-Loeve (KL) decomposition and the polynomial chaos (PC) expansion are elegant and efficient tools for uncertainty propagation in porous media. Over recent years, KL/PC-based frameworks have successfully been applied in several contributions for the flow problem in the subsurface context. It was also shown, however, that the accurate solution of the transport problem with KL/PC techniques is more challenging. We propose a framework that utilizes KL/PC in combination with sparse Smolyak quadrature for the flow problem only. In a subsequent step, a Lagrangian Monte Carlo sampling technique is used for transport, where the flow field samples are calculated very efficiently based on the solutions at relatively few quadrature points. To increase the computational efficiency of the PC-based flow field sampling, a new reduction method is applied. Compared to a conventional full MC method that includes both flow and transport, the proposed PC/MC method (PCMCM) for flow/transport, respectively, saves on the computational cost of the flow problem. The applicability of PCMCM is demonstrated for transport simulations in multivariate Gaussian log-conductivity fields that are unconditional and conditional on conductivity measurements.

Wireless sensor networks (WSNs) provide a convenient way to monitor the physical environment. Exploiting the context-aware capability of WSN to achieve energy conservation in intelligent buildings is an attractive direction. We therefore propose an intelligent and personalized energy-conservation system by wireless sensor networks (iPower). This system consists of some WSNs connected to a control server, some power-line control devices, and some user identification devices. A WSN is deployed in each room to monitor the usage of electric appliances and to help the control server to determine if there are electric appliances that can be turned off to reduce unnecessary energy consumption. The iPower system is quite intelligent and can adapt to personal need by automatically adjusting electric appliances to satisfy users' requirements. The design and implementation details of iPower are reported in this paper.

The two proposed conceptual models explaining partially saturated flow from soil into fractured rock in the intermediate fractured vadose zone have not been confirmed due to the difficulty involved in observing the soil-rock interface in situ. To address that challenge, this paper presents a series of newly developed physical experiments using a geotechnical centrifuge model of sand overlying a single dry clean smooth vertical fracture. The model shows the development of a perched water system and a saturated wetting front that progresses transversely along the interface, while breaching through the interface occurs via multiple point sources. The dominant flow mechanisms within the fracture comprise droplets, discontinuous rivulets with droplet formation, and continuous rivulets. A maximum drainage area of 30% of the width of the fracture contributes to the flow in the model, and this drainage area decreases with depth due to the merging of oscillating rivulets in the upper regions of the fracture. The presence of evidence supporting both conceptual models shows that a combined conceptual model is required to accurately explain partially saturated flow at the soil-rock interface.

Work accidents in Indonesia are still likely to be high even though the Company received a certificate of Occupational Safety and Health Management System (SMK3) soaring up 70%. In these phenomena there are indications of declining productivity of construction workers. One of the unique construction results is the property mall. In Jakarta itself has built 80 malls with various classes. The application of SMK3 in each legal civil activity must be carried out in accordance with Government Regulation no. 50 of 2012 which is integrated with the company's regulations. The research was conducted on the participants of mall management building in Jakarta and in cooperation with PT XYZ one of the developers and managers of a large mall in Jakarta. It is necessary to evaluate the factors of the application of SMK3 that affect the productivity of workers in fit out mall work. The data was taken with field surveys, interviews and questionnaires as well as supporting data. It uses 7 free v...

The dispersion in fluid-saturated deformable or nondeformable porous media with or without chemical reaction is studied analytically, considering a series of particular cases selected through different practical problems using different dispersion models. The required basic equations are obtained using mixture and homogenization theories. Different analytical and numerical models valid for large time (asymptotic) and for all time (transient) are explained. The formulations of the problems considered here are so general that they are applicable to deformable and nondeformable particles amenable to both analytical and numerical procedures. The validity of the results obtained from an analytical method is verified by comparison with available experimental and cell model results, and good agreement is found.

The authors have carried out numerical computations of water impact on a twodimensional flat-bottomed body using a volume-of-fluid method based on a modified SOLA-VOF code. The method has a flexibility of allowing air flows to be considered in the computations. The results are found to be consistent with those presented in tmother investigation, although the assumptions of the present study are much simplified and the conditions of impact were slightly different.

The lubrication approximation is applied to electro-osmotic flow through a thin parallel-plate channel under the combined effect of charge and hydrodynamic slippage modulation on the walls. The walls are periodically patterned for the charge and slip distributions, with a wavelength much longer than the channel height. It is shown that the phase of the wall patterns will play a significant role in determining the section-averaged velocity as well as the local convection pattern, quantitatively and qualitatively. The effect of the phase on the flow will be dramatically different, depending on whether the electric field is applied along or perpendicular to the varying direction of the patterns. The possibility of generating a net flow in a direction perpendicular to the applied field is demonstrated.

In this paper, coupled response measurements are suggested for detection of a transverse surface crack in a cantilever beam. The crack has been modelled by a local compliance matrix of six degrees of freedom and simulated for detection. The eigenfrequencies are obtained using finite element method (FEM) and are compared with those of experiments. However, the small changes in eigenfrequencies are not enough for crack detection. The flexibility matrix contains non-diagonal terms, and thus indicating the coupling among the different modes of vibrations. A harmonic force of known amplitude and frequency is used to dynamically excite the beam in bending mode. But due to the presence of crack, the bending excitation induced the axial and torsional vibrations also. The measurements of direct (bending) response and coupled (axial and torsional) responses are carried out using triaxial accelerometer and rotational laser vibrometer (RLV). The experiments are carried out for different bending frequencies, crack depths and locations. The results indicate that the coupled responses are very sensitive to crack; hence these measurements are suggested for crack detection.

In the present contribution, the diffraction and pressure-dependent-radiation problems for an array of OWC’s devices restrained in regular waves with finite water depth is investigated in order to highlight the effect of the hydrodynamic interactions among the devices on the wave loading and wave energy extraction. The problem of the hydrodynamic interaction among neighbouring OWC devices may be important in evaluating the absorbed wave energy by each device in the array since the hydrodynamic characteristics of each member of a multi OWC’s configuration may differ from the ones of a standalone, isolated device due to interaction phenomena. The latter are evaluated using the single OWC’s hydrodynamic characteristics and the physical idea of method of multiple scattering (Twersky’s [1952], Okhusu [1974], Mavrakos [1991]). Air volume flow rate, inner pressure and absorbed wave power are parametrically evaluated for several distances among devices in an array consisting of three devices.

Electromagnetic flowmeters (known as magnetic flow meters) are a widely used type of flowmeter. This study examines the performance of magnetic flow meters when the electrodes in the meter are positioned at two different orientations: electrodes parallel with the plane of an upstream 90degree short radius elbow and electrodes perpendicular to the plane of an upstream 90-degree short radius elbow. Four different meters from four different manufacturers were included in the study in which a baseline straight pipe test was first performed using over fifty diameters of straight pipe upstream of each meter. The four meters were then installed at five different locations downstream from a 90-degree short-radius elbow. At each location the meters were tested in two orientations at five different flow rates. From this research, shifts in the flow rate were observed with the electrodes located at two different orientations. Theses shifts in flow rate ranged from 0.01% to 4.40% of the total flow measurement, and the average shifts in flow rate ranged from 0.07% to 2.78%. For the purposes of this study, the shift in flow rate is the percentage relative to the baseline test. The results from this research illustrated that there is a significant difference in measurement accuracy when the meter electrodes are installed at different orientations relative to the plane of the bend.

Researchers have produced sophisticated modal split and transit demand models, including forecasts that are sensitive to the level of service. However, little effort has been made to integrate these models into corridor studies and route alignment analyses since (a) re-routing is itself an extremely complex modeling task, and (b) the results of the demand models are presented in tabular form with no facility to visualize spatial patterns and relationships that, if recognized, would aid in the routing tasks. GIS tools can be used, together with the demand models, to identify both clusters of city blocks that house families with certain socioeconomic characteristics and potential trip destinations conducive to transit use. In other words, GIS tools can be used to better measure some of the factors that are needed by transit demand models. The results of these models can be displayed graphically, enabling analysts to target places needing improved service, evaluate route re-alignment alternatives, and operate more efficient and effective bus lines. This paper examines how a particular class of model used by transit agencies for estimating ridership can be integrated with GIS tools in order to facilitate such analyses. It also explores the effects of visualization of routes, demographics, and employment data on the process of designing route alignments with better targetingof high transit ridership areas. This paper is part of aresearch project sponsored by the Region Oneuniversity Transportation Center, at MIT.