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(1) The enactment of Sub-Decree No. 113/2015 on Solid Waste Management marked a significant policy shift towards the decentralisation of waste management in Cambodia and some progress has been observed in Phnom Penh and some other large cities and tourist destinations. However, information in rural areas is lacking. Rapid and simple waste assessment methodologies are needed in rural areas where waste data is scarce and different waste management measures are required compared to urban areas. This study aimed to fill the information gap on the status and fate of municipal solid waste management in rural areas by focusing on three underrepresented cities in different geographical areas through empirical studies. (2) Rapid waste assessments, including waste composition analysis, truck scaling, waste recovery surveys, waste flow analysis, and waste hotspot surveys, were conducted. (3) The per capita waste generation averaged 0.44 kg/day, which is lower than the national average, but did not show significant differences between income levels. The waste composition was similar to that of urban areas, with plastics making up more than 20% of the waste. There were major contrasts in the waste collection rates, with one city having a high rate (85.9%) while the other two cities were as low as 22.6% and 24.2%, respectively. This suggests that rural cities in Cambodia are at different stages of transition in establishing their waste management systems after the decentralisation of waste management to municipalities. The main cause of the low waste collection rate was that private waste collectors were finding it difficult to collect service fees. In the absence of waste collection services, a total of 370 waste hotspots were identified outside of the waste collection areas, where littering and open burning of waste were common. (4) Addressing these challenges requires urgent development of sustainable financing mechanisms, enhanced institutional capacities, and implementation of targeted awareness-raising programmes. These measures are essential for providing basic waste collection and disposal services, as well as for curbing littering and open burning of waste in rural cities in Cambodia. [ABSTRACT FROM AUTHOR]

A global water crisis has led to thriving industry of desalination seawater for past decades. Desalination process of seawater through reverse osmotic (RO) membrane separation is the most widely used in a water treatment process as its effectiveness in separating the dissolved solute from seawater solution and able to produce clean water. However, scaling problems, organic fouling, particulate matter, and biofouling are common types of foulant that can be occurred on the surface membranes layer during the separation process. Thus, a numerical study on the separation process using RO membrane was conducted where 2D spiral wound membrane model was developed by COMSOL© Multiphysics 5.5 software which the aim is to determine the factors that influence the formation of scaling on the RO membranes surface layer. In this study, concentration polarization of calcium carbonate on membrane surface was determined at three range of parameters; pressure (P=15-35 bar), temperature (T=30-60°C) and concentration of ion calcium carbonate (Ci=5000-15,000 mg/L). It shows a significant effect on the formation of concentration polarization on the membrane surface where at T=30, 45 and 45 °C, the permeate flux obtained are 21.9, 24.6 and 26.8 L/m2hr, respectively. While, for the ion concentration factor, the obtained permeate flux for 5000, 10,000 dan 15,000 mg/L, are 22.3, 25.7 dan 27.4 L/m2hr, respectively and for the pressure factor, the permeate flux obtained are 21, 28 and 34 L/m2hr at P=15, 25 and 35 bar, respectively. Through this study, it was found that this developed spiral wound membrane model can estimate the potential scaling of the ion calcium carbonate on the membrane surface layer up to 70% efficiency. Thus, this model can be applied in the desalination of seawater to identify the optimum operating parameters, aid in the dosage selection of anticipants, and estimate fouling mitigation effects in the pressure-driven membrane filtering process. [ABSTRACT FROM AUTHOR]

The effects of strength grades, loading modes, and stress levels on the performance deterioration of sustainable recycled aggregate concrete (RAC) subjected to mechanical loading or coupled mechanical loading and environmental actions are investigated in this study. Comparison analysis of residual properties of RAC suffered from single mechanical loading, coupled actions of mechanical loading, and salt-solution freeze-thaw cycles, as well as the combined actions of mechanical loading and salt-solution corrosion were experimentally studied. The results indicate that the stress level is the most influential factor affecting the durability of RAC followed by the RAC strength grade and the number of times the alternating load applied. Moreover, applying novel intermittent loading mode to simulate the durability of RAC under the coupled actions of sustained loading and environmental factors is feasible and reasonable. Additionally, the fitting equations were proposed to discuss the effects of number of times the alternating load applied, stress level, and mechanical strength on the mechanical strength loss and durability of RAC. [ABSTRACT FROM AUTHOR]

Motivated by applications to image reconstruction, in this paper we analyse a finite-difference discretisation of the Ambrosio-Tortorelli functional. Denoted by " the elliptic-approximation parameter and by ε the discretisation step-size, we fully describe the relative impact of " and ε in terms of δ -limits for the corresponding discrete functionals, in the three possible scaling regimes. We show, in particular, that when δ and ε are of the same order, the underlying lattice structure affects the ?Γ-limit which turns out to be an anisotropic free-discontinuity functional. [ABSTRACT FROM AUTHOR]

Highlights • We present an enhanced method for scaling modes from operational modal analysis. • The new method includes residual terms. • The new method can handle closely coupled and repeated modes. • We verify the method on two sets of experimental data. Abstract Modal models from operational modal analysis (OMA) lack information about the modal scaling (or, modal mass). Many times, this is not a limitation. However, in some engineering applications, e.g. for structural health monitoring or computational model validation, a scaled modal model may be important. The authors of this paper recently presented a new approach for scaling modal models using harmonic excitation. The method was named the OMAH method, and it was shown that the approach is robust and reliable. However, the proposed technique relied on the measurement of the structural response between two arbitrary degrees of freedom (DOFs) for each mode. In the present paper, the method is extended to the case in which several excitation and response DOFs may be taken into account for the scaling. This is analogue to using global parameter estimation methods in classical experimental modal analysis. The proposed multiple-reference technique includes the capability of estimating residual terms to account for modes outside the frequency range of interest. The method is validated on two sets of data from real full scale structures, and the accuracy of the scaling using several response DOFs is shown to improve compared to using only a single excitation and response DOF. The proposed formulation, furthermore, allows one or more excitation DOFs as well as one or more response DOFs to be used for the scaling of the modal model. Thus, one single formulation can be used regardless of whether multiple-references are necessary, or not. [ABSTRACT FROM AUTHOR]

Hydrological modelling is an important tool for research, policy, and management, but uncertainty remains about parameters transferability from field observations made at small scale to models at the catchment scale and larger. This uncertainty compels the need to develop parameter relationships that are translatable across scale. In this study, we compare the changes to modelled processes as resolution is coarsened from 100‐m to 1‐km in a topographically complex, 255‐km2 Colorado River headwater catchment. We conducted a sensitivity analysis for hydraulic conductivity (K) and Manning's n parameters across four orders of magnitude. Results showed that K acts as a moderator between surface and subsurface contributions to streamflow, whereas n moderates the duration of high intensity, infiltration‐excess flow. The parametric sensitivity analysis informed development of a new method to scale effective hydraulic conductivity across modelling resolutions in order to compensate for the loss of topographic gradients as resolution is coarsened. A similar mathematical relationship between n and lateral resolution changes was not found, possibly because n is also sensitive to time discretization. This research provides an approach to translate hydraulic conductivity parameters from a calibrated coarse model to higher resolutions where the number of simulations are limited by computational demand. [ABSTRACT FROM AUTHOR]

Abstract The effective strength of butt joints under uniaxial tensile loading significantly depends on the adhesive thickness as well as on the elastic contrast of adhesive and adherend. For an assessment of their impact using sensitivity analysis, for joint design optimisation, or for an efficient evaluation of butt joint test data, a suitable modelling approach is desired. In the present work, the joint's failure is modelled assuming a spontaneous formation of finite cracks along the interface between adhesive and adherend. A coupled stress and energy approach is used requiring only two fundamental material parameters, that is, material strength and toughness. Presuming the length of initiating cracks to be small compared to the adhesive thickness, the method of matched asymptotic expansions in combination with a complex potential formalism is applied. This enables an efficient description of the stress distribution in the vicinity of the bi-material notch tip and the derivation of scaling laws for the energy dissipation during crack nucleation. The joint strength is calculated for a varying adhesive thickness and for different layups of the composite adherends. The theoretical predictions based on the asymptotic coupled stress and energy approach are validated against numerical cohesive zone data and experimental findings from literature. [ABSTRACT FROM AUTHOR]

Biomass gasification in fluidized beds is a complex process in which particles occur in a wide range of size and density. In this paper, the mixing behavior of the char, biomass and bed material in a gasification reactor of a typical dual fluidized bed (DFB) system was investigated in a cold flow model. Experiments with ternary mixtures were performed in which the size and the density of the used particles were varied. For the experiments, a cold flow model was constructed with a full bed material recirculation loop, similar to DFB systems. Experiments revealed that at low fluidization velocities, the smaller char particles and biomass particles occur more preferentially in the bed material recirculation stream. If the fluidization velocities are increased, this tendency diminishes. Furthermore, the experiments showed that the mass fraction of biomass particles in the recirculation stream is always higher than that of the lighter char particles. It is also shown that the current design of the gasification reactor in DFB systems is not optimal. A way to overcome this issue in existing plants is presented. [ABSTRACT FROM AUTHOR]

Since penetration tests of concrete targets against rigid projectiles are commonly conducted in reduced geometrical scale, whether the replica scaling law holds or not is very important for extending the knowledge based on the small-scale experiments to the large-scale or prototype penetration scenarios. In this paper, based on the available experimental data for depth of penetration (DOP) and discussions on the empirical formulae, it is verified that the replica scaling law is satisfied for DOP in rigid projectile penetrations, as long as the scaling is done strictly for both projectiles and concrete targets including the coarse aggregates. And the coarse aggregates with invariant size (not replica-scaled) could account for the non-scaling effect in DOP found in tests and empirical formulae. To explore the non-scaling effect in DOP caused by aggregates, a 3D mesoscopic finite element model for concrete target is developed. Based on the parametric analyses, it indicates that, the magnitude of the non-scaling effect decreases with the increasing of the cement strength when the aggregate strength is fixed. While the influence of the aggregate strength on the non-scaling effect is not so obvious comparing with the influence of cement strength. Besides, the magnitude increases with the increasing of the volume fraction of aggregates. These conclusions imply that, the non-scaling effect in DOP for different concrete targets with the same magnitude implied by the empirical formulae, and the always held scaling law in the (semi-)analytical models, may be unreasonable. Finally, based on the numerical results, a semi-analytical model for predicting DOP is proposed, which improved our previous model by further considering the non-scaling effect. [ABSTRACT FROM AUTHOR]

This paper presents an improved technique to analyze the stability margin of the discrete systems. The presented approach is based on the reduced conservatism of eigenvalues and scaling of Gerschgorin circles. The mathematical proof and sufficient condition with suitable scaling is stated for the conservatism of eigenvalues. Moreover, the presented technique is demonstrated with the numerical examples. Further, the improved results are compared with the existing methods. [ABSTRACT FROM AUTHOR]

The main objective of this study was to investigate the effect of magnetic treatment on the physico-chemical and bacteriological characteristics of hard waters. The scaling power of tested waters was evaluated using the rapid controlled precipitation (RCP) method. Results showed that magnetic treatment affects calcium carbonate crystallization. The RCP tests confirmed that the scaling power of the magnetically treated water was inhibited. Experimental results also indicated a significant improvement in the bacteriological quality of the treated water. Average reductions of 2.02 log Total coliforms, 0.95 log Escherichia coli and 1.06 log Faecal streptococci were obtained. [ABSTRACT FROM AUTHOR]

A multi-level via or ‘supervia’ (SV) is considered as a scaling booster for the next technology nodes, as it may lower routing resistance and parasitic capacitance as compared to a conventional dual damascene (DD) via. In this paper, we present a three-level SV integration scheme at 16 nm half-pitch along with its 3-D RC extraction. 3-D interconnect geometries are modeled by means of process emulations, performed by using Synopsys' Sentaurus Process Explorer. The resistance of DD vias is also extracted for comparing with SV for various metal and barrier-liner (M-BL) combinations. The R extraction is done based on a resistivity model, calibrated to imec hardware and integrated into Synopsys' Raphael™ tool [1]. Simulations of SV structures with novel M-BL combinations show up to 60% resistance reduction for the investigated interconnect configurations with respect to the DD Cu-TaNCo reference ( R  = 105 Ω) at a total BL thickness of 3 nm. Furthermore, an approach to compare SV vs DD via capacitance is proposed, which suggests ~16% reduction in parasitic capacitance of SV schemes compared to DD schemes. [ABSTRACT FROM AUTHOR]

The mechanism of concrete deterioration in sodium sulfate solution is investigated. The macroperformance was characterized via its apparent properties, mass loss, and compressive strength. Changes in ions in the solution at different sulfate attack periods were tested by inductively coupled plasma (ICP). The damage evolution law, as well as analysis of the concrete’s meso- and microstructure, was revealed by scanning electron microscope (SEM) and computed tomography (CT) scanning equipment. The results show that the characteristics of concrete differed at each sulfate attack period; the drying-wetting cycles generally accelerated the deterioration process of concrete. In the early sulfate attack period, the pore structure of the concrete was filled with sulfate attack products (e.g., ettringite and gypsum), and its mass and strength increased. The pore size and porosity decreased while the CT number increased. As deterioration progressed, the swelling/expansion force of products and the salt crystallization pressure of sulfate crystals acted on the inner wall of the concrete to accumulate damage and accelerate deterioration. The mass and strength of concrete sharply decreased. The number and volume of pores increased, and the pore grew more quickly resulting in initiation and expansion of microcracks while the CT number decreased. [ABSTRACT FROM AUTHOR]

Complex analysis methods such as non-linear time-history analyses (NTHA) are often required for the design of non-standard bridges. The selection of the ground motions for the NTHA is a crucial task as the results of the analyses show a wide variability according to the selected records. In order to predict the demand in accordance with the seismic hazard conditions of the site, the selected motions are usually modified by scaling procedures. Within this context, the performance of two scaling methods, namely the Modal Pushover Based Scaling (MPS) and ASCE/SEI procedures, are compared for the NTHA of a large bridge, the Demirtas Viaduct (longitude 29.10°, latitude 40.28°), in this study. The system comprised of 28 spans was idealised with two different analytical models in order to assess the effect of the modelling on the scaling procedures results. The effects of the hazard level on the scaling results were evaluated. The required number of motions for conducting effective analyses, i.e. the minimum number of motions for estimating the target goals, was investigated at different hazard levels. MPS reduced the dispersion considerably more than the ASCE scaling, indicating sets can be formed with fewer motions to predict the target levels. [ABSTRACT FROM PUBLISHER]

Experimental tests of the collision of reduced scale naval structures is here detailed described. First, a web girder section constructed in two different scales, 1/1 and 1/4, is subjected to the impact of a rigid indenter at mid span. The second experiment employs a more complex structure: a head-on collision of a 1/100 scaled tanker against a rigid obstacle. Special attention is given to some similarity complications that are frequent in real tests: model yielding stress different from the prototype and material strain rate. Since the standard similarity laws are unable to deal with those issues, it is shown how to modify the scaling factors to generate a replica similar to the corresponding prototype. Results are shown that support the approach with the modified scaling factors producing a behavior closer to the full-size structure. In the study of the ship head-on collision, only a 1/100 scaled specimen could be tested. In this case, the equivalent prototype was calculated with the assistance of the scaling factors and compared with empirical formulations found in the literature. The methodology depicted in this manuscript can be used as a guidance for scaled impact tests of vessels and other types of large structures. [ABSTRACT FROM AUTHOR]

Scaling criteria are used to evaluate the performance of a reservoir by deriving dimensionless groups which affect a specific enhanced oil recovery (EOR) process. The relationships among different process controlling factors are investigated in this approach by comparing the dimensionless numbers. Scaling criteria can capture continuous alteration of rock and fluid properties related to fluid flow through porous media which can be characterized by different dimensionless groups. In this study, a critical review of scaling criteria development is made based on published inspectional and dimensional analyses of fluid flow through porous media for oil-water displacement processes. This paper provides the basic concepts of scaling and dimensionless groups along with the review of recent works on scaling criteria development for EOR processes. This paper discusses how scaling criteria are developed using the existing techniques and reviews both their merits and demerits. The history of dimensional analysis is reviewed, starting with the first notions of dimensions to the powerful methods of recent times. This study reviews briefly some relevant analytical and semi-analytical works which are related to scaled model development for petroleum reservoirs. Understanding the basics of these mechanisms will assist petroleum engineers to analyze, design and evaluate EOR processes. This study will also help in developing dimensionless mathematical models for fluid flow through porous media. [ABSTRACT FROM AUTHOR]

We explore bursty multiscale energy dissipation from earthquakes flanked by latitudes 29° S and 35.5° S, and longitudes 69.501° W and 73.944° W (in the Chilean central zone). Our work compares the predictions of a theory of nonequilibrium phase transitions with nonstandard statistical signatures of earthquake complex scaling behaviors. For temporal scales less than 84 hours, time development of earthquake radiated energy activity follows an algebraic arrangement consistent with estimates from the theory of nonequilibrium phase transitions. There are no characteristic scales for probability distributions of sizes and lifetimes of the activity bursts in the scaling region. The power-law exponents describing the probability distributions suggest that the main energy dissipation takes place due to largest bursts of activity, such as major earthquakes, as opposed to smaller activations which contribute less significantly though they have greater relative occurrence. The results obtained provide statistical evidence that earthquake energy dissipation mechanisms are essentially 'scale-free', displaying statistical and dynamical self-similarity. Our results provide some evidence that earthquake radiated energy and directed percolation belong to a similar universality class. [ABSTRACT FROM AUTHOR]

Scaling by metal silicates represents a major obstacle for geothermal systems. A composition that enables the fabrication of artificial deposits is necessary for the rapid testing of potential inhibitors. In this work, artificial deposits were synthesized by employing experimental conditions similar to those in the Tuzla Geothermal Field in Turkey. Although refluxing enabled the formation of a precipitate that was similar to naturally formed deposits in color and texture, their elemental composition and morphology showed a mismatch. An autoclave enabled the production of a precipitate that more closely resembled naturally formed deposits in color, texture, elemental composition, and structure. [ABSTRACT FROM AUTHOR]

The source properties and scaling relationships for small and moderate earthquakes occurring in Israel and adjacent areas are investigated. We determine source parameters such as corner frequency, seismic moment, static stress drop, and source radius using three-component short period and broadband seismograms recorded by the Israel Seismic Network from 1993 to 2010. In this study about 2000 seismograms from 300 regional earthquakes in the magnitude range of $$1.5 \le M_{d} \le 5.2$$ have been analyzed. To identify possible differences in source scaling depending on regional features the analysis is performed separately for three regional earthquake sequences that occurred in Southern Lebanon, Dead Sea basin and Gulf of Aqaba. The analyzed regional earthquakes exhibit corner frequencies ranging from 0.9 to 9.7 Hz, which correspond to seismic moments from 1.580E+11 to 5.82E+16 Nm. Our estimates of Brune's stress drop for regional earthquakes are in the range of 0.005-19 MPa with a clear tendency to higher stress drops for larger events. Source radii for the earthquake range from ~100 to ~1600 m. Source spectra of small to moderate earthquakes are normally compared with the classical Brune one-corner spectral model, which includes a flat portion at low frequencies and decreasing as $$\omega^{ - 2}$$ at high frequencies. However, some spectra in the dataset are complex and a second corner frequency is apparent, exhibiting substantial deviations of individual source spectra from the ideal $$\omega^{ - 2}$$ spectral shape. [ABSTRACT FROM AUTHOR]

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Recent studies have shown that ocular dominance plasticity in layer 2/3 of the visual cortex exhibits a formof homeostatic plasticity that is related to synaptic scaling and depends on TNFa. In this study, we tested whether a similar form of plasticity was present in layer 2/3 of the barrel cortex and, therefore, whether themechanismwas likely to be a general property of cortical neurons. We found that whisker deprivation could induce homeostatic plasticity in layer 2/3 of barrel cortex, but not in a mouse strain lacking synaptic scaling. The time-course of homeostatic plasticity in layer 2/3 was similar to that of L5 regular spiking (RS) neurons (L5RS), but slower than that of L5 intrinsic bursting (IB) neurons (L5IB). In layer 5, the strength of evoked whisker responses and ex vivo miniature excitatory post-synaptic currents (mEPSCs) amplitudes showed an identical time-course for homeostatic plasticity, implying that plasticity at excitatory synapses contacting layer 5 neurons is sufficient to explain the changes in evoked responses. Spontaneous firing rate also showed homeostatic behaviour for L5IB cells, but was absent for L5RS cells over the time-course studied. Spontaneous firing rate homeostasis was found to be independent of evoked response homeostasis suggesting that the two depend on different mechanisms. [ABSTRACT FROM AUTHOR]

In this paper, the effects of NaCl concentration on saturation in concrete and ice-formation pressure and volume expansion of solutions are investigated; also, mechanisms of concrete salt-frost scaling are analyzed. Results show that the ice-formation pressure and volume expansion of solutions are significantly reduced with increased NaCl concentration, which positively affects the reduction of salt-frost scaling of concrete. On the other hand, the capillary-uptake degree of saturation and water-uptake rate in concrete obviously increase with increased NaCl concentration, which negatively affects the reduction of salt-frost scaling. According to the measured data, the ice-formation pressure in concrete is calculated, and the result quantitatively proves that the ice-formation pressure generated by 2-6% NaCl solution causes maximal concrete damage. [ABSTRACT FROM AUTHOR]

We investigate the structural, magnetic, ferroelectric properties, dielectric response, and scaling behavior of Aurivillius compound Bi 4.25 Gd 0.75 Fe 0.5 Co 0.5 Ti 3 O 15 . The substitution of Gd can effectively enhance the room-temperature ferromagnetic property. The ferromagnetic and ferroelectric Curie temperature can be determined to 370 K and 1088 K, respectively. Four thermally activated dielectric relaxations in the temperature range of 10–1000 K are observed. The first dielectric relaxation in cryogenic temperature range (50–100 K) can be attributed to electron hopping between Co 2+ and Co 3+ through bridging oxygen vacancies V o . The second one in 300–500 K can be ascribed to the electron localized transfer between Co 2+ and Co 3+ . The third one in dielectric anomaly region (500–800 K) arising from the trap-controlled ac conduction around the doubly ionized oxygen vacancies V o . The last one in high temperature range (above ∼800 K) may be originate from viscous motion of domain wall. Moreover, scaling behavior reveals the dynamic process of electrons is independence of temperature. [ABSTRACT FROM AUTHOR]

This paper describes a selective mass scaling method which is designed for the analysis of wave propagation problems in nearly incompressible materials. The incompressibility of materials leads to a high value of the compressional wave speed, which makes the time step extremely small in explicit time integration method. The proposed selective mass scaling method selects the eigenfrequencies related to volumetric deformation modes to decrease them, while it keeps the shear eigenmodes unchanged. This makes the time step no longer limited by the compressional wave speed but by the shear wave speed. A significant reduction of CPU time is obtained with a good accuracy for transient problems in small strains on free or largely prestressed media. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Several types of deterioration have developed at earthen sites of the Ming Great Wall in Qinghai Province, including cracks, gullies, collapses, sapping, and scaling off, the first four of which could threaten the wall's stability. The correlations of these types of deterioration with each other and with other factors were explored. The authors selected 16 sampling points from nine typical earthen sites of the wall to investigate its deterioration. Linear fitting of the data on the types of deterioration was conducted to determine their correlations. Then, indoor tests of these samples were systematically performed to clarify the physical, water-related, and mechanical properties of the rammed earth, and meteorological data for each county were collected. Finally, the linear fitting was carried out among the deterioration indices, engineering-related parameters of the rammed earth, and meteorological data to determine the influence of these factors on the development of each type of deterioration. This research illustrates the mechanisms involved in such deterioration and its evolution from a macro perspective. [ABSTRACT FROM AUTHOR]

Surfaces of rock joints were classified by means of the computerized procedure utilizing three-dimensional reliefs. These standard reliefs were formed as fractal objects using scaling properties of rock joints. Applicability of the computational scheme was tested and verified. [ABSTRACT FROM AUTHOR]

The far-zone correlation between intensity fluctuations with polychromatic beams generated by quasi-homogeneous sources is investigated by giving two illustrative examples. The analyses show that, in general, the frequency components of correlation between intensity fluctuations may change on propagation. Moreover, we have discussed the extreme case of critical angle at which no frequency shift occurs, and also proposed the so-called scaling law for correlation between intensity fluctuations. [ABSTRACT FROM AUTHOR]

This study focuses on evaluating recycled concrete aggregate (RCA) of high quality produced through a protocol that preserves the original properties of the concrete to be recycled. Concrete with RCA of preserved quality was compared to concrete with commercially available RCA. A total of 29 mixes were tested with RCA replacement ranging from 30% to 100% of the coarse aggregate. Results showed that concrete with RCA of preserved quality performed significantly better in compressive strength, drying shrinkage, and salt scaling resistance. Furthermore, the use of 30% RCA with preserved quality produced concrete of comparable quality to that of concrete with natural aggregate. [ABSTRACT FROM AUTHOR]

On November 2013, typhoon Haiyan devastated parts of central Philippines, creating a need for shelter for the thousands of residents displaced. Several relief organizations facilitated construction of thousands of shelters. This paper presents an experimental study performed to verify the structural capacity of one particular shelter. The shelter studied is of a transitional nature, with initial floor dimensions of 4.1 m by 3 m, but allowing for expansion. The structure is composed of a timber braced frame with a galvanized steel roof. Because of the non-conventional lateral force resisting system used in the shelter, a full-scale test under simulated lateral wind forces was performed. The main goals of the experiment were to confirm analytical results, and to determine failure mechanisms, lateral stiffness and the lateral capacity. The shelter's capacity was higher than the design demand, confirming the analytical results. The test was stopped when significant uplift deformations of the elevated post bases (EPBs), used to anchor the shelter columns to the concrete foundations, were observed at the columns in tension. This finding motivated further evaluation of the EPBs. Results from individual EPBs confirmed the full-scale test observations. [ABSTRACT FROM AUTHOR]

A reduced order analytical model for peeling of elastic thin films and interface fracture is presented by treating the thin film as a finite length beam with interface interactions accounted for by cohesive zone modeling. The results obtained are shown to be in excellent agreement with finite element simulations and experimental data. Scaling analysis and equations for steady state load and crack length are derived that clearly summarize their parametric dependence. [ABSTRACT FROM AUTHOR]

This study presents a scaling analysis of the time development of clear-water scour depth at bridge piers. It shows that the widely-used exponential formula can be theoretically derived with scaling arguments. The derivation provides connections between the physical pier-scouring process and two empirical constants used in the formula. The dependence of the two constants on sediment coarseness is calibrated using published laboratory data with scour duration ranging from 49 to 1094 h. The analysis presented is restricted to conditions, including steady flow, clear-water scour, narrow circular cylindrical pier, and uniform sediment with low coarseness. [ABSTRACT FROM AUTHOR]

The additivity model assumed that field-scale reaction properties in a sediment including surface area, reactive site concentration, and reaction rate can be predicted from field-scale grain-size distribution by linearly adding reaction properties estimated in laboratory for individual grain-size fractions. This study evaluated the additivity model in scaling mass transfer-limited, multi-rate uranyl (U(VI)) surface complexation reactions in a contaminated sediment. Experimental data of rate-limited U(VI) desorption in a stirred flow-cell reactor were used to estimate the statistical properties of the rate constants for individual grain-size fractions, which were then used to predict rate-limited U(VI) desorption in the composite sediment. The result indicated that the additivity model with respect to the rate of U(VI) desorption provided a good prediction of U(VI) desorption in the composite sediment. However, the rate constants were not directly scalable using the additivity model. An approximate additivity model for directly scaling rate constants was subsequently proposed and evaluated. The result found that the approximate model provided a good prediction of the experimental results within statistical uncertainty. This study also found that a gravel-size fraction (2 to 8 mm), which is often ignored in modeling U(VI) sorption and desorption, is statistically significant to the U(VI) desorption in the sediment. [ABSTRACT FROM AUTHOR]

Freezing-thawing (F-T) exposure produces higher absorption in concrete than an isothermal condition. This work investigated the moisture absorption characteristics in different air-entrained concrete mixtures under two exposure conditions (water and a 3% salt solution) by simultaneously monitoring the weight change, mass loss and internal damage of 100 × 100 × 70 mm concrete blocks subjected to repetitive F-T cycles. The results indicate that permanent bulk moisture uptake is primarily a result of the accelerated saturation of poorly connected capillary pores, the slow filling of entrained air voids in concrete mixes with sufficient air entrainment, or the re-saturation of newly generated cracks in concrete with poor frost resistance. No detectable discrepancy was observed in moisture uptake between water and salt exposures, but the mass loss difference was found to be substantial. The measured bulk absorption is not a reliable predictor for salt frost scaling resistance, since it reflects the universal moisture condition in the specimen while scaling deterioration is dominated by the degree of saturation in a thin surface region. [ABSTRACT FROM AUTHOR]

Despite its importance in many applications and processes, a complete and unified view on how nano- and microscale asperities influence hydrodynamic interactions has yet to be reached. In particular, the effects of surface structure can be expected to become more dominant when the length scale of the asperities or textures becomes comparable to that of the fluid flow. Here we analyze the hydrodynamic drainage of a viscous silicone oil squeezed between a smooth plane and a surface decorated with hexagonal arrays of lyophilic microsized cylindrical posts. For all micropost arrays studied, the periodicity of the structures was much larger than the separation range of our measurements. In this thin channel geometry, we find the hydrodynamic drainage and separation forces for the micropost arrays cannot be fully described by existing boundary condition models for interfacial slip or a no-slip shifted plane. Instead, our results show that the influence of the microposts on the hydrodynamic drag exhibits three distinct regimes as a function of separation. For large separations, a no slip boundary condition (Reynolds theory) is observed for all surfaces until a critical (intermediate) separation, below which the position of the no-slip plane scales with surface separation until reaching a maximum, just before contact. Below this separation, a sharp decrease in the no-slip plane position then suggests that a boundary condition of a smooth surface is recovered at contact. [ABSTRACT FROM AUTHOR]

Understanding co-evolving networks characterized by the mutual influence of agents' actions and network structure remains a challenge. We study a co-evolving inverse voter model in which agents adapt to achieve a preferred environment with more opposite-opinion neighbors by rewiring their connections and switching opinion. Numerical studies reveal a transition from a dynamic partially satisfied phase to a frozen fully satisfied phase as the rewiring probability is varied. A simple mean field theory is shown to capture the behavior only qualitatively. An improved mean field theory carrying a longer spatial correlation gives better results. Motivated by numerical results in networks of different degrees and mean field results, we propose a scaling variable that combines the rewiring probability and mean degree in a special form. The scaling variable is shown to work well in analyzing data corresponding to different networks and different rewiring probabilities. An application is to predict the results for networks of different degrees based solely on results obtained from networks of one degree. Studying scaling behavior provides an alternative path for understanding co-evolving agent-based dynamical systems, especially in light of the trade-off between complexity of a theory and its accuracy. [ABSTRACT FROM AUTHOR]

The goal of the study was applying machine learning methods to create rules for prediction of the surface scaling resistance of concrete modified with high-calcium fly ash. To determine the scaling durability the Boras method, according to European Standard procedure (PKN- CEN/TS 12390-9:2007), was used. The results of numeral experiments were utilized as a training set to generate rules indicating the relation between material composition and the scaling resistance. The classifier generated by BFT algorithm from the WEKA workbench can be used as a tool for adequate classification of plain concretes and concretes modified with high-calcium fly ash as materials resistant or not resistant to the surface scaling. [ABSTRACT FROM AUTHOR]

This experimental work is focused on understanding behavior of thin walled filament wound cylindrical Glass Reinforced Epoxy (GRE) tubes subjected to lateral indentation. These tubes are supported by V shaped cradles at each end. Scaling factors are established by using Buckingham Pi theorem for input parameters including geometric dimensions of the specimens, indenter, V shaped supports and indentation speed. Indentation tests are carried out to understand compliance of output parameters including force, energy and damage. Damage growth is recorded throughout the test by video camera and growth rate is calculated by using post experiment image processing. This work presents experimental results including slope of the force–displacement relation, energy absorbed and permanent deformation experienced by each specimen. Damage initiation and growth with respect to indentation displacement, force, energy and time is plotted and scaled to understand compliance with the scaling law. The force displacement, energy displacement and damage growth rate is compared with the existing results from the literature. Some interesting comparisons are observed between the current and existing results in the literature for a study even not meant for scaling analysis. Damage growth rate for all specimens collapse on same trend when data is scaled with non-dimensional factor n 3 . [ABSTRACT FROM AUTHOR]

A variable metric stochastic theory of the elastic constants of textile composites with stochastic yarn (or tow) geometry has been developed in the current study. A variable metric coordinate transformation is utilized in this theory to introduce the cross-section shape fluctuations of yarn into the compliance of textile composites. Six parameters are defined to describe the positioning and cross-section shape of yarn completely. Then, the Taylor expansions of the local stochastic variable metric basis and the compliance of yarn are executed. Finally, the volumetric averaging method is employed to obtain the elastic properties of textile composites. The numerical simulations show that the fluctuations of geometric parameters may affect the elastic response of textile composites considered. The example of single straight yarn proves the validity of the theory and presents the explicit formulas of influence of stochastic yarn geometry on elastic constants. Within the example of plain weave composite, random yarn cross-section shape and twist degrade all of the elastic constants except the shear moduli and Poisson’s ratios in 1–3 and 2–3 directions, which are determined by the comprehensive effect of the stochastic scaling and twist. [ABSTRACT FROM AUTHOR]

This paper presents design and analysis for engineering the thermal and mechanical time constants of piezoresistive thermal oscillators. The optimal design is obtained by minimizing the threshold current density required to initiate self-sustained oscillations. Optimizing the oscillator geometry is of extreme practical importance given that the threshold current densities (GA/m2) are close to the breakdown current densities observed in silicon. The equivalent circuit model of the oscillator is used along with the lumped thermal, mechanical, and piezoresistive parameters to calculate the threshold current density of the oscillator. The optimal ratio of the thermal and mechanical time constants is found to be 3 for bulkmode oscillators where the in-plane dimensions control the mechanical resonant frequency. The final frequency of oscillations is obtained as a function of the mechanical resonant frequency, quality factor (Q), and the ratio of the time constants. Results show that scaling the dimension (or frequency) has a weak sub-linear effect on the oscillator performance. Finally, we compare different bulk modes, based on the calculated threshold dc currents for a 1-GHz oscillator. [ABSTRACT FROM PUBLISHER]

Frost damage is considered to be a typical material deterioration in the concrete structures subjected to external environmental conditions. The effect of different types of steel and polypropylene fibers on the surface scaling resistance of concrete subjected to cyclic freezing and thawing in the presence of deicer salt was analyzed. The test parameters included fiber type and dosage and the type of concrete surface subjected to freezing and thawing. Both the cut and cast surfaces of specimens were tested. The dispersed steel reinforcement was found to improve the scaling resistance significantly. However, the effectiveness of fibers was related to their shape and dimensions. The beneficial effect of polypropylene fibers on salt scaling resistance was apparent only in case of the extruded fibers with treated surface. [ABSTRACT FROM AUTHOR]

The scaling resistance of concrete with strength grades of 30 MPa (C30) and 50 MPa (C50) subjected to different types (A and B) and concentrations (3, 5, and 20%) of deicing salt solution were studied using an accelerated freezing-thawing test. Deicing Salt A was composed of about 80% sodium chloride and 20% calcium chloride, B was composed of 70% sodium chloride, 25% magnesium chloride and 5% calcium chloride. The changes in strength, mass loss and relative dynamic modulus of elasticity of concrete were examined during the testing. The results showed that the salt scaling resistance of C50 was better than that of C30. The former could pass 160 freezing-thawing cycles while the latter could pass only 95 cycles. Specimens showed the largest deterioration when subjected to 5% solution, and the smallest deterioration when subjected to 20% solution after 200 cycles. Deicing salts with a higher percentage of NaCl and CaCl2 demonstrated a more obvious deterioration effect on concrete. The incorporation of 5% silica fume (by the mass of binder) or 1% high-efficiency air entraining agent significantly improved the salt scaling resistance of the concrete, even no visible deterioration was observed after 200 cycles. The main scaling deterioration features of concrete include surface spalling and cracking. Microstructural examinations indicated that formation of Friedel's salt resulting from chemical reaction between NaCl or CaCl2 and calcium aluminate hydrates could lead to the deterioration of concrete during salt scaling testing. [ABSTRACT FROM AUTHOR]

The modal-pushover-based-scaling (MPS) procedure has been developed for appositely selecting and scaling earthquake records for nonlinear response history analyses (RHAs) of multi-story symmetric-plan and single-story unsymmetric-plan buildings. This procedure is extended here to unsymmetric-plan buildings with significant torsional response under bi-directional earthquake excitations. The accuracy of the procedure is evaluated by using three-dimensional computer models of nine unsymmetric-plan buildings with 5, 10 and 15 stories. These models were subjected to nonlinear RHAs considering sets of seven far-field records selected and scaled according to the extended modal-pushover-based-scaling (EMPS) procedure. Structural responses were compared against benchmark values, defined as the median values of the engineering demand parameters (EDPs) due to a larger set of unscaled far-field records. Also examined here is the ASCE/SEI 7-10 scaling procedure for comparison purposes. This study clearly shows that the EMPS procedure provides much superior results in terms of accuracy (true estimates of expected median EDPs) and efficiency (reduced record-to-record variability of EDPs) than the ASCE/SEI 7-10 scaling procedure for far-field ground motions. Thus, the EMPS is deemed to be an appropriate procedure for nonlinear RHAs of multi-story unsymmetric-plan buildings. [ABSTRACT FROM AUTHOR]

A simple and empirical scaling approach is proposed for predicting the unsaturated hydraulic conductivity (Kus) based on the microscopic characteristic length (λ). The approach was tested on 19 different soils. The results showed that the proposed approach was useful for a wide range of soil water content, except at relatively high soil moisture. The predictedλ(θ) values were overestimated by 2%, which led to 5% overestimation in prediction ofKus(θ) at soil matric potentials of less than –0.1 MPa. However, the predictions ofKus(θ) were not satisfactory at soil matric potentials of greater than –0.1 MPa. The results also revealed that the proposed approach was accurate for predictingKus(θ) in the dry range of soil water content. Future models should be developed based on the empirical and physical scaling approaches to improve prediction of soil hydraulic properties at high water contents. This means that new scaling factors need to incorporate more information about the pore geometry.Editor D. Koutsoyiannis; Associate editor A. Carsteanu [ABSTRACT FROM AUTHOR]

The potential for using a distributed fibre optic strain sensor system to detect and quantify localised reinforcement deterioration and explore the failure mechanism of reinforced concrete beams is investigated. The objective is to discover whether distributed fibre optic strain sensors installed either internally or externally can detect pitting corrosion in reinforced concrete beams, and be used to better understand structural behaviour. These sensors enable strain to be measured along the full length of the fibre optic cable, whereas conventional electrical resistance strain gauges offer discrete measurements that may not capture localised strain changes. Axial tension tests on reinforcement bars demonstrate that deterioration detection is possible, but that quantification of deterioration is not necessarily straightforward, depending on the extent of deterioration. Four-point bending tests on reinforced concrete beams illustrate that localised deterioration can be detected and quantified with embedded sensing fibres and that cracks can be detected using externally bonded fibres. The top and bottom reinforcement strain profiles are used to demonstrate that the unexpected ultimate failure loads of the beams are the result of specimens behaving as tied arches at failure. Overall the distributed fibre optic sensor system proves to be effective for detection and quantification of localised deterioration and provides the necessary data to assess the beam failure mechanism. [ABSTRACT FROM AUTHOR]

The effects of mineral powders on scaling, water absorption and internal deterioration of concretes are studied. Properties of a reference concrete produced with Portland cement are compared with corresponding mineral powder concretes. In the mineral powder concretes the Portland cement is replaced by 10 or 20 wt% by either limestone or quartz powder. Some mixes also contain a further addition of 10 and 20 wt% of these powders to the Portland cement. Surface scaling and internal damage tests and a capillary suction test are performed on the concretes, to obtain a basic understanding of the freeze-thaw durability of the mineral powder concretes. The results suggest that the use of mineral powders itself does not have an effect on the freeze-thaw resistance, but the consequent binder reduction and loss of strength impairs durability. The loss of strength resulting from the replacement of the cement and the consequent reduction in the freeze-thaw durability might be compensated for by reducing the water/cement (w/c) ratio of the mineral powder concretes. This may be possible because the use of mineral powders increases the flow, that is, reduces the water demand of the test concretes. [ABSTRACT FROM AUTHOR]

Numerical simulations are performed to validate a nondimensional dynamic scaling procedure that can be applied to subsurface and deeply moored systems, such as hydrokinetic ocean renewable energy devices. The prototype systems are moored in water 400 m deep and include: subsurface spherical buoys moored in a shear current and excited by waves; a subsurface ocean current turbine excited by waves; and a deeply submerged spherical buoy in a shear current excited by strong current fluctuations. The corresponding model systems, which are scaled based on relative water depths of 10 and 40 m, are also studied. For each case examined, the response of the model system closely matches the scaled response of the corresponding full-sized prototype system. The results suggest that laboratory-scale experimentation of complete ocean current renewable energy systems moored in a current is possible. [ABSTRACT FROM PUBLISHER]

When it comes to dynamically loaded concrete structures, determining the real degree of fatigue damage of a structure on site is a very demanding process that has not been explored in depth. Calculation concepts according to current codes and specifications (e.g. fib Model Code for Concrete Structures 2010 []) do not offer efficient results for this task. However, the permanent monitoring from the erection of a structure up to the end of its lifetime is seen as a very promising possibility for assessing the degree of damage constantly. This article takes a closer look at the concrete fatigue concept of fib Model Code 2010 [], shows an FE simulation of a time-dependent fatigue process for an offshore wind turbine foundation and presents a fatigue monitoring concept including laboratory tests, which enables the detection of the real degree of deterioration in a concrete structure. During tests, the use of ultrasound was identified as the most appropriate method. Measuring wave velocity enables the determination of the dynamic E-modulus, which correlates to the degree of damage within the cross-section of the structure considered. [ABSTRACT FROM AUTHOR]