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This paper describes analytical modelling for the non-contact tip, root, and end relieving of spur gears and their associated volumetric material removal rate (MRR) by the pulsed electrochemical finishing (PECF) process. The models were developed using Faraday's law of electrolysis and involute geometry of spur gears. The developed models are validated experimentally using the innovatively designed and developed cathode gears and experimental apparatus by varying voltage, pulse-on time, and pulse-off time at four levels each. It found that minimum prediction errors for the developed models for the amount of tip, root, and end relief are 0.8%, 0.3%, and 1.3%, respectively, and minimum prediction error for models of volumetric MRR of tip, root, and end relief are 6.9%, 0.6%, and 9.8% respectively. A study of microgeometry along the profile and lead direction of spur gear confirmed that the PECF process not only successfully imparted tip, root, and end relief but also reduced their arithmetical average roughness and maximum height by 61.1% and 62.5% for tip relief, 67.7% and 67.8% for root relief, and 63.8% and 66.6% for end relief respectively. It also removed hob cutter marks and cracks revealed from the comparison of surface morphology of spur gear flank surfaces before and after tip, root, and end relieving. Maximum values of % reductions in maximum height and arithmetical average roughness occurred for pulse-on and pulse-off times as 3 and 4 ms (i.e., 43% duty cycle). The developed models will be very useful in designing or predicting the amount of tip, root, and end relief that can be imparted for a given modification duration. Conversely, they can be used for parametric optimization of the PECF process and to compute the required duration for the PECF process to impart the desired amount of tip/root/end relief to spur gears. [Display omitted] • Development of analytical models of tip, root, end relief for anodic spur gears in PECF process. • Microgeometry confirms designed cathode gears through PECF process imparted tip, root, end relief. • Analytical model predicted values of root, tip, and end relief closely agree with their experimental values. • Cathode gears through PECF considerably reduced surface roughness of tip/root/end relieved spur gears. • Predicted and experimental relief values enhance with voltage, pulse-on time, reduce with pulse-off time. [ABSTRACT FROM AUTHOR]

In this paper, the work hardening rate of Al-Zn-Mg-Cu alloy in the conditions of solid solution and thermo-mechanical coupled fast aging were investigated separately, and the main research content and results are as follows. Under the solid solution processes at different temperatures, the uniaxial tensile test curves of work hardening rate are relatively dispersed at a lower strain rate, and the work hardening rate increases with the increase of solution temperature. Then, as the strain rate increasing, the work hardening rate curves at each solution temperature gradually converge, until all curves intersect at a common intersection point. The above mechanism is attributed to the comprehensive effect of precipitates, solid solutions, and dynamic strain aging in the matrix. For the thermo-mechanical coupled aging, the work hardening rate has a great different with that of solid solution process. Consequently, the influence of pre-deformation on the work hardening rate were investigated, which concludes the curve shape type and the softening coefficient. The introduction of dislocation have some significant influences on the work hardening rate. Firstly, it makes the shape of work hardening rate curves change from shape 1 to shape 2. On the other hand, as the pre-deformation increasing, the variation law of softening coefficient shows an abnormal trend that is different from the ordinary law, which is due to the coordinated effect between dislocation density and dislocation induced precipitation. Furthermore, in order to reveal the internal mechanism in depth, the microstructure are observed by TEM (Transmission electron microscope). Finally, a targeted set of analytical models for work hardening rate were established, especially the mathematical explanation of the multicollinearity phenomenon of work hardening rate curves in the solid solution condition. • Influence of dynamic strain aging on the work hardening rate. • Work hardening rate under dislocation induced precipitation conditions. • Build models for the multi-line coplanarity of work hardening rate curves. [ABSTRACT FROM AUTHOR]

A novel shear connection system for GFRP box-concrete composite girder was proposed and experimentally and analytically investigated in this paper. The novel connection system consists of T-bolts and sand coating, and can be easily installed at the GFRP box section with closed shape. The proposed connection system can improve the slip stiffness of GFRP box-concrete interface, and provide sufficient shear resistance and ductility. The effects of low temperatures (T = 20, −30, −60, and −80 ℃), longitudinal spacing of T-bolts (S L =100, 150, and 200 mm), aspect ratio (h ef / d =3.2, 5.2, and 7.2), and GRRP-concrete interface type (IT =combined connectors with T-bolts and sand coating, sand coating, T-bolts, and blind-bolts) on interfacial shear behaviours were evaluated through twenty-four push-out tests. Failure modes and load-slip/strain curves at different temperatures were plotted. Experimental results showed that decreasing temperature from 20 to − 80 ℃ increased the shear resistance of sand coating and slip stiffness of push-out testing specimens, but exhibited little effects on their ultimate shear resistances. Analytical equations to predict the ultimate shear resistances of push-out testing specimens have been developed and validated by the test results. Besides, load-slip modes for specimens with different interface types were also proposed with good accuracy. • Combined connectors with T-bolt and sand coating are proposed for composite girder. • Combined connectors improve the slip stiffness, shear resistance and ductility. • Low temperature increases the interfacial shear resistance and slip stiffness. • Analytical models predict well the ultimate shear resistance and load-slip curves. [ABSTRACT FROM AUTHOR]

In this paper, the shear mechanism of the novel Y-shaped (Y-S) connector encased in ultra-high-performance concrete (UHPC) was analyzed to reveal the steel-concrete interface separation mechanism and the interaction mechanism between the connector and UHPC. Subsequently, a validated finite element (FE) model was established for parametric analysis to investigate the effects of strength parameters and structural parameters on the shear performance of the Y-S connector, including the yield strength of the steel plate and penetrating rebar, the compressive strength of the concrete and UHPC, the diameter of the penetrating rebar, the effective width and thickness of the steel plate, and the dimensions of the UHPC shear pocket. The design method for the Y-S connector was finally developed and validated, including the improved shear capacity model, the shear stiffness model, the peak slip model, and the method for calculating the load-slip curves. The results indicate that the UHPC dowel in the holes experiences triaxial compressive stress, and the penetrating rebar undergoes deformation under the force from the top and bottom UHPC. The yield strength of the steel plate, as well as the effective width and thickness of the steel plate, have remarkable effects on the shear performance of the Y-S connector compared with other parameters. These analytical models can well predict the shear performance of the Y-S connector in the required precision range. • The shear mechanism of the Y-S connector encased in UHPC was analyzed. • Validated FE models were established to conduct parametric analysis. • Analytical models to predict shear performance of the Y-S connector were put forward. • Design process was developed to realize the application in engineering practices. [ABSTRACT FROM AUTHOR]

Quantifying incident solar radiation on a surface is a complex task that requires the knowledge of geometric, geographical, astronomical, physical and meteorological characteristics of the location. The aim of this paper is to analyze the attenuation processes of the solar radiation and to review the scientific works in this field, specifically the analytical models for solar irradiance calculation, as well as to establish an alternative method to compute the magnitude of the overall atmospheric transmittance. Analytical models have been developed since 1940 and they have been improving in precision and complexity. Up until now, the Bird & Hulstrom model is the most complete and accurate of them all. The main disadvantage of this model is that a great number of equations and parameters such as temperature, sunshine hours, humidity, etc. are required. In this paper, a very fast and accurate new method is developed to quantify solar irradiances at any site. The analysis shows that the parameters required are only the type of climate, altitude and state of the atmosphere. This method also allows to quantify the influence of the turbidity degree in both direct and diffuse irradiances. That information is essential to select which solar technologies are suitable in each place. As an application, the new method has been implemented and characterized in Mexico. Solar energy is an abundant resource in Mexico, and there are some studies about the solar energy potential in that country, but the influence of physical and meteorological factors on the solar radiation have not been related. In this study, the meteorological information of 74 weather stations located in different climates of the country were used to determine the parameters required. The results have been validated with experimental data available for different locations. [ABSTRACT FROM AUTHOR]

This paper provides a comprehensive overview of existing experimental and modelling approaches to determine effective diffusion coefficients of water saturated ordinary Portland cement-based materials. A dataset for diffusivity obtained from different experimental techniques have been presented for cement paste, mortar and concrete. For cement paste at low porosities, diffusivity reported by different authors varies up to a factor of five and electrical resistivity measurements for low capillary porosity are up to one order of magnitude higher compared to other techniques. Experimental data of mortar and concrete reveals predominant influence of increasing tortuosity due to aggregates and limited influence of interface transition zone. Hence, a particular emphasis has been placed on assessing predictability of diffusivity models for cement paste on a larger dataset collected in this paper. It has been observed that all predictive models have similar level of accuracy and fail to predict electrical resistivity data at low capillary porosity as these models are not calibrated using electrical resistivity data. [ABSTRACT FROM AUTHOR]

Data-driven investigations are increasingly dealing with non-moderated, non-standard and even manipulated information Whether the field in question is journalism, law enforcement, or insurance fraud it is becoming more and more difficult for investigators to verify the outcomes of various black-box systems To contribute to this need of discovery methods that can be used for verification, we introduce a methodology for document structure-driven investigative information retrieval (InvIR) InvIR is defined as a subtask of exploratory IR, where transparency and reasoning take centre stage The aim of InvIR is to facilitate the verification and discovery of facts from data and the communication of those facts to others From a technical perspective, the methodology applies recent work from structured document retrieval (SDR) concerned with formal retrieval constraints and information content-based field weighting (ICFW) Using ICFW, the paper establishes the concept of relevance structures to describe the document structure-based relevance of documents These contexts are then used to help the user navigate during their discovery process and to rank entities of interest The proposed methodology is evaluated using a prototype search system called Relevance Structure-based Entity Ranker (RSER) in order to demonstrate its the feasibility This methodology represents an interesting and important research direction in a world where transparency is becoming more vital than ever. • Investigative information retrieval is a sub-task of exploratory search with more emphasis on transparency and reasoning. It can be used to complement black-box methods with regards to verification and transparency. • Relevance structures can be used to help a user better understand how documents are relevant to the queries and to navigate complex data collections. • Formal evaluation of the Relevance Structure-based Entity Ranker demonstrates the viability and value of the proposed methodology of document structure-driven investigative information retrieval. [ABSTRACT FROM AUTHOR]

Traditionally, FPGA designers make use of CAD tools for evaluating architectures in terms of the area, delay and power. Recently, analytical methods have been proposed to optimize the architectures faster and easier. A complete analytical power, area and delay model have received little attention to date. In addition, previous works use analytical methods to optimize general-purpose FPGA architectures. Using analytical models for optimizing application-specific FPGA architectures are interesting subjects in the reconfigurable computing field. In this way, designers can investigate the optimized architecture for a set of application circuits and the consumers can find their best architecture among a variety of devices which is optimal for their specific work. In this paper, we complete an analytical FPGA performance model by presenting an analytical model to estimate the dynamic and leakage power and by integrating it into the geometric programming framework. This way, we are able to rapidly analyze various FPGA architectures and select the best one in terms of power consumption as well as area and delay. In the next step, we extend the model for optimizing FPGA architectures for a set of applications. A case of the best architecture for two specific circuits has been investigated in this paper. [ABSTRACT FROM AUTHOR]

• In-plane mechanical properties of birch plywood are experimentally determined. • An exhaustive dataset on strength and elastic properties of birch plywood in tension, compression, and shear has been established. • High load-to-face-grain angle dependency is observed for each property. • Analytical models that show sufficient closeness to the test data are suggested. There is an increasing demand for engineered wood products in modern structures. Birch plywood is promising in structural applications, due to the combined advantages of its superior mechanical properties and the cross lamination configuration. However, the off-axis mechanical properties of birch plywood have not been thoroughly investigated. The aim of this paper is to establish a comprehensive experimental dataset that could serve as the input in the analytical or numerical models to design birch plywood under various load conditions. Specifically, tensile, compressive and shear tests were conducted under five different angles to the face grain, i.e., from 0° (parallel) to 90° (perpendicular) to the face grain, with an interval of 22.5°. The stress–strain relationships, failure modes, strength and elastic properties of birch plywood are highly dependent on the load-to-face-grain angle. The strength and the elastic properties are also predicted by various analytical and empirical models. Parametric analyses are performed to study the influence of the interaction coefficient F 12 in Tsai-Wu failure criterion and the Poisson's ratio ν x y in the transformation model on the predicted strength and modulus respectively. Lastly, the possibilities of predicting the on-axis shear modulus based on the off-axis uniaxial tests are discussed in this paper. [ABSTRACT FROM AUTHOR]

Previous research focused on the optimization of conventional stud-to-track wall systems for moderate blast threat level protection. It has been concluded that adding extra screws is a practical and an efficient solution for altering the failure mechanisms and increasing the blast resistant characteristics of these wall systems. This paper is focused on the evaluation of the static blast-resistance of conventional cold-formed steel stud wall systems. A general analytical model of the resistance, which is the first necessary step for performing dynamic response predictions under blast, is presented in this paper. A case study of sufficiently screwed stud-to-track connection is selected for further inspection and investigation. Particular emphasis is placed on the effect of including utility holes and sheathing on the static resistance of the wall system. For each experimental test, strain data were collected up to the failure point from a total of 11 longitudinal strain gauges installed on locations of interest. A finite element model was developed to include the sheathing effect and to add flexibility to the simulation of the conventional connection. Strain results provided insightful observations about the behavior of the stud and were used to validate the numerical simulations as well. [ABSTRACT FROM AUTHOR]

Mobile cloud computing is a new paradigm that uses cloud computing resources to overcome the limitations of mobile computing. Due to its complexity, dependability and performance studies of mobile clouds may require composite modeling techniques, using distinct models for each subsystem and combining state-based and non-state-based formalisms. This paper uses hierarchical modeling and four different sensitivity analysis techniques to determine the parameters that cause the greatest impact on the availability of a mobile cloud. The results show that distinct approaches provide similar results regarding the sensitivity ranking, with specific exceptions. A combined evaluation indicates that system availability may be improved effectively by focusing on a reduced set of factors that produce large variation on the measure of interest. The time needed to replace a fully discharged battery in the mobile device is a parameter with high impact on steady-state availability, as well as the coverage factor for the failures of some cloud servers. This paper also shows that a sensitivity analysis through partial derivatives may not capture the real level of impact for some parameters in a discrete domain, such as the number of active servers. The analysis through percentage differences, or the factorial design of experiments, fulfills such a gap. [ABSTRACT FROM AUTHOR]

A sustainable hydraulic system is proposed to cool the slurry manure and mitigate the ammonia emissions of livestock buildings, a major source of environmental pollution. In this paper, analytical and numerical methods are used to evaluate the energy efficiency and the mitigation capability of the hydraulic cooling system. Results show that annual primary energy use of only 6.08 kWh per animal can reduce 5.87 kg of ammonia per animal per year. The system is most efficient for manure with less than 12% total solids content. Results also show that the liquid region above the cooling pipes features one-dimensional transient heat transfer formed by unique flow patterns. A simplified analytical model is derived to predict the surface temperature of liquid manure. The analytical solution shows that the manure surface temperature can be reduced by 7.4 and 12 °C after 2 and 5 h, respectively. The temperature reduction results in up to 37.3% decrease in ammonia emissions with only 0.8% of the total energy use in livestock buildings. • An energy efficient cooling system is proposed to reduce emissions from buildings. • Using primary energy of only 6.08 kWh can reduce 5.87 kg NH3 per animal per year. • The cooling system uses only 0.8% of the total energy use in a livestock building. • The cooling system can reduce up to 37.3% NH3 emissions from livestock buildings. • An analytical model is derived to predict the surface temperature of liquid manure. [ABSTRACT FROM AUTHOR]

• The shear-compression failure modes confined UHPC were explained, and the effects of parameters on the axial stress–strain curves of confined UHPC were analyzed. • The prediction models for the axial stress–strain curves of confined UHPC were established. • The prediction models for the peak stress and peak strain curves of confined UHPC were developed. The axial stress–strain models of confined ultra-high performance concrete (UHPC) were important key inputs for analytical programs to predict the full-range loading deformation of confined UHPC. The concrete columns confined with stirrups under axial compression tended to be a failure in shear-compression failure. However, the existing models for evaluating the axial stress–strain models of confined UHPC did not consider the shear-compression failure. In this paper, an experiment on the axial stress–strain behaviour of confined UHPC was presented. The specimens consisted of 75 UHPC with compressive strength up to 155.45 MPa were confined by spiral stirrups. According to test results, a theoretical model for axial stress–strain curves of confined UHPC by considering the shear-compression mechanism of UHPC was developed. In the proposed models, the real lateral stress of stirrups was adopted to calculate the lateral confinement of stirrups, rather than assumed that the stirrups reached the yield strength. In addition, the effects of dowel action of stirrups and longitudinal reinforcement were considered. Furthermore, the prediction models for the compression behaviour indicators of confined UHPC included peak stress, peak strain, initial tangent modulus, residual stress, and residual strain were proposed. By comparing with existing models, the proposed analytical models of axial stress–strain curves of confined UHPC had high accuracy and high stability. [ABSTRACT FROM AUTHOR]

• The half-lap joint has an inclined lapped surface with screws as fasteners. • Four-point bending tests were conducted considering axial compressive forces. • Analytical models were developed for glulam components with half-lap joints. • Axial compressive force improved the capacity and stiffness of spliced components. • Axial compressive force enabled spliced components to fail in a more ductile manner. Glulam gridshells provide a preferred structural form for large-span structures due to their aesthetic appearance and structural efficiency. As the gridshell span becomes large, the length challenge of glulam members associated with the manufacturing and transportation limits needs to be well addressed. Attention should also be paid to the influence of spliced joints on the structural performance of large-span glulam gridshell structures. This paper studies the effect of a type of commonly used half-lap spliced joints on mechanical properties of structural components for large-span glulam gridshell structures. Experimental tests were conducted on a series of full-scale intact and spliced glulam components. Two boundary conditions (i.e., roller and hinge supports) were employed in the tests, investigating the influence of axial compressive forces on the mechanical performance of glulam components. The failure modes, moment-rotation responses, moment capacities, rotational stiffnesses, and ductility factors of the specimens were compared. The test results showed that the moment capacity and the initial rotational stiffness of the roller-supported spliced specimens respectively reached 43.0% and 55.6% of the capacity and stiffness of the intact specimens. Compared to the roller-supported spliced specimens, the axial reaction force provided by the hinge support suppressed the initiation and growth of cracks within the tension zones of the spliced specimens, enabling them to fail in a more ductile manner. Analytical models were then developed to predict the moment capacity of glulam components with half-lap joints. The models were validated by the test results and can serve as a convenient tool for designing such joints. [ABSTRACT FROM AUTHOR]

• The flexural performance of the corroded RC beams strengthened using UHPC was investigated. • The effect of configuration and thickness of the UHPC layers were examined. • The analytical models to predict the ultimate flexural strength of strengthened beams were developed and validated. In the present paper, an experimental investigation was carried out to examine the effect of configurations and thicknesses of ultra high performance fiber reinforced concrete (UHPC) layers on the flexural performance of reinforced concrete (RC) beams strengthened using UHPC layers after undergoing different degrees of accelerated reinforcement corrosion. The beams were tested under flexure to evaluate the effect of UHPC strengthening (with combinations of three UHPC layer thicknesses and two configurations) on failure modes, flexural strengths, and stiffnesses. Statistical analysis of the flexural test results using analysis of variance (ANOVA) showed the significant effects of both configuration and thickness of the UHPC layers on the performance of corrosion-damaged RC beams in flexure, irrespective of the degree of reinforcement corrosion. The RC beams strengthened with UHPC layers applied on three sides exhibited the most significant increase in the ultimate flexural strength in the range of 6 to 63% and an increase in the stiffness in the range of 28 to 112% as compared to that of the uncorroded control beam. Furthermore, analytical models were developed to predict the flexural strength of the corroded beams strengthened using different configurations of UHPC layers. The close agreement of the ultimate flexural strength between the experimentally obtained results and analytically predicted values for the strengthened RC beams indicates the accuracy of the developed analytical models, which can be used to select an optimum strategy for strengthening the corrosion-damaged RC beams. [ABSTRACT FROM AUTHOR]

Abstract: Most analytical models for the design of piled embankments or load transfer platforms with geosynthetic reinforcement (GR) include two calculation steps. Step 1 calculates the arching behaviour in the fill and step 2 the load-deflection behaviour of the GR. A calculation method for step 2 based on the results of model tests has been published by Van Eekelen et al. (2012a,b). The present paper analyses and presents a new model for step 1, which is the arching step. Additional tests, which are also presented in this paper, were conducted for this purpose. The new model is a limit-state equilibrium model with concentric arches. It is an extension of the models of Hewlett and Randolph (1988) and Zaeske (2001). The new model results in a better representation of the arching measured in the experiments than the other models mentioned, especially for relatively thin fills. Introducing GR in a piled embankment results in a more efficient transfer of load to the piles in the form of an arching mechanism. The load is then exerted mainly on the piles and the GR strips between the piles, on which the load is approximately distributed as an inverse triangle. The new model presented in this paper describes this behaviour and is therefore meant to describe the situation with GR. The new model provides a physical explanation for observations of the arching mechanism, especially the load distribution on the GR. Other observations with which this model concurs are the dependency on fill height and friction angle. The amount of arching increases with increasing subsoil consolidation and GR deflection. The paper describes how the new model relates to the development of arching as a result of subsoil consolidation. [Copyright &y& Elsevier]

Abstract: This paper concentrates on organising, planning and managing the train movement in a network. The three classic management levels for rail planning, i.e., strategic, tactical and operational, are introduced followed by decision support systems for rail traffic control. In addition, included in this paper are discussions on train operating forms, railway traffic control and train dispatching problems, rail yard technical schemes and performance of terminals, as well as timetable design. A description of analytical methods, simulation techniques and specific computer packages for analysing and evaluating the behaviour of rail systems and networks is also provided. [Copyright &y& Elsevier]

• The techno-economic models for the horizontal ground heat exchangers are presented. • The analytical and numerical models are generalised by different approaches. • The economic models are developed based on different economic indicators. • The net present value is about £24000–£30000 with payback period of 4–10 years. Geothermal heat pump has been widely recognized as one of the promising technologies for building applications because of its high energy efficiency and low operating expense, however the high capital investment and installation costs discourage building owners to choose such a system. The horizontal geothermal heat pump system with reduced cost is a viable option that would be utilized widely, the aim of this paper is to catalogue and critique a range of effective approaches for the horizontal geothermal heat pump systems in different regions based on techno-economic assessment data. A ground heat exchanger is a vital component of the horizontal geothermal heat pump. The state-of-the-art analytical and numerical models of the linear-loop, slinky-coil and spiral-coil ground heat exchangers are generalized, in addition to their advantages and disadvantages. A large number of economic evaluation methods for analysing the financial performance of the horizontal geothermal heat pump system are presented. At the end, the standpoints, recommendations and potential future study on the horizontal geothermal heat pump system are deliberated. [ABSTRACT FROM AUTHOR]

• The effectiveness of TRMs as a means for confinement of masonry was investigated. • A total of 39 column type specimens were tested in concentric axial loading. • The TRM jackets increased both the strength and ductility. • Analytical models calibrated to predict the strength and the ultimate strain. The present paper demonstrates the results of an experimental and analytical research programme on masonry structures confined with Textile Reinforced Mortars (TRMs). A total of 39 small scale masonry columns were subjected to uniaxial compression tests after being strengthened with TRM layers. The variables studied during the experiments were, the number of TRM layers, the cross-section aspect ratio and the corner radii. The purpose of this experimental investigation was to examine the influence of the aforementioned parameters on the performance of confined masonry. In general, the TRM jackets increased substantially both the strength and the ductility of the confined specimens. The results obtained from the current experimental study allowed the development of a simple set of equations, using a linear and a non-linear approach, for the prediction of the strength and the ultimate strain of TRM-confined masonry. The non-linear approach gives a better approximation for the prediction of the compressive strength, and the relevant strain. Further experimental investigation is needed in the future to include more types of fibers, textiles, mortars, and masonry materials. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the measurement of decarburization of steel rods with an electromagnetic sensor using an analytical model both in online and offline scenarios. Loss of carbon (decarburization) at the steel surface can have a significantly detrimental effect on mechanical properties of products, since hardness, fatigue, strength and wear properties are strongly dependent on carbon content. Currently, measurement of decarburization is by destructive methods, such as metallographic observation or hardness tests on a sample cross-section after processing. A non-destructive EM method is proposed in this paper. An analytical solution for the inductance of a circular air-cored coil encircling a steel rod is deduced and further a simplified model is obtained which shows that for both online and offline cases, the thickness of the decarburisation layer is proportional to the inductance difference with and without decarburisation. Using this simplified model, decarburisation thickness can be obtained. The results have been verified by both finite element models and metallographic observations. [ABSTRACT FROM AUTHOR]

Abstract: The use of elements connected through compression at their contact surfaces, without tensile capacity, which allow rocking in their transverse direction, was attempted in the construction of bridge piers, masonry walls and frame structures. Columns or bridge piers can be designed to rock or overturn with minimal lateral resistance. However, as shown in this paper, due to the effects of stresses at the contact surfaces, including cracking, yielding and crushing, the lateral resistance varies substantially before rocking and before the columns overturn. Moreover, when the elements are confined between rigid surfaces, or when pre-stressing forces are applied to the connections, the lateral resistance varies substantially. Current models discretized using micro-models, or finite elements, are computationally inefficient for large structural systems, such as bridges or buildings. This paper attempts to model the strength and stiffness variation before rocking, using a macroscopic approach. The stiffness and flexibility formulations developed using virtual work concepts include flexural and shear effects, and can be implemented in many off-the-shelf analytical platforms. The analytical formulations are compared in this paper to the results of multi-purpose finite element models (FEM) for squat and slender columns. [Copyright &y& Elsevier]

• Estimate the traffic demand integrating information provided by traditional and new technologies. Explore the inherent properties of extended coverage information. • Deal with splitting ratios of demand flows among paths identified by coupled Bluetooth sections. • Derivate the analytical solving procedure. • Increase of the intercepted path flows or spatial coverage leads to more accurate estimates. • Assess the effectiveness of the proposed method on a study network in Rome, Italy. Recent advances in technology have made available numerous new monitoring systems that collect updated traffic measurements both in fixed locations and over specific corridors or paths. Such recent technological developments point to challenging and promising opportunities for Origin-Destination (OD) traffic demand estimation and forecast. Therefore, the aim of this paper is to study how to exploit available information detected by new monitoring devices in the estimation of traffic demand. Starting from the formulation proposed by Spiess (1987, 1990), in this paper a new method to estimate the traffic demand by means of Bluetooth data is proposed. It explores inherent properties of this information in an off-line (and static) context, where mathematical formulation of the estimation problem can be derived. The effectiveness of the proposed method has been investigated in an extensive plan of experiments carried out both on test networks and on a study network consisting in a part of the city of Rome, Italy, obtaining promising results in both applications. [ABSTRACT FROM AUTHOR]

Seismic isolation is generally considered an effective earthquake protection strategy. As application of seismic isolation increases, decisions on the use of one particular isolator versus another isolator increasingly depend on computed responses with complex analytical models. Accordingly, validation of analytical models to predict primary (structural) and secondary system (non-structural component) response in seismically isolated buildings becomes very important. This paper presents comparisons of experimental and analytical results on the primary and secondary system response of a building model in order to provide information on the accuracy of the predicted response. The tested model was configured as a 6-story building at quarter length scale in a moment-frame configuration, and with the following seismic isolation systems: a) Low damping elastomeric bearings with and without linear or nonlinear viscous dampers, b) Single Friction Pendulum (FP) bearings with and without linear or nonlinear viscous dampers, and c) Lead-rubber bearings. Response quantities compared include story drifts and isolator shear forces and displacements for the primary system, and peak floor total velocities and floor response spectra that relate to secondary system response. This paper presents samples results out of a total of 288 comparisons of experimental and analytical results presented in an MCEER report. It is shown that the primary and secondary system response is computed with sufficient accuracy by the analytical models but some response quantities may be underestimated or overestimated by significant amounts. • Accuracy of analytical models to predict primary and secondary system response in seismically isolated buildings was investigated. • It presents comparisons of experimental and analytical results on the primary and secondary system response of a building model in order to provide information on the accuracy of the predicted response. • It presents samples results out of a total of 288 comparisons of experimental and analytical results. • The primary and secondary system response is computed with sufficient accuracy by the analytical models. • Response quantities compared for the primary system, and the secondary system response. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the deformation behavior of the SiC reinforced aluminum matrix composite in laser forming was investigated. A 2KW Nd:YAG laser was used to deform the composite at different laser powers, scanning speeds, numbers of irradiation passes and beam diameters. It was found that the bending angle increases with an increase in laser power, and a decrease in scanning speed and beam diameter. A relatively linear relationship between bending angle and number of irradiation passes was observed, and the effect of microstructural changes on the deformation behavior was discussed. An analytical model based on the Vollertsen''s two-layer model was developed to predict the bending angle of the composite. The trends of the predictions are in good agreement with the experimental results. The effect of reinforcements on deformation behavior of the composite was further theoretically investigated. By modeling the changes of physical, thermal and mechanical properties including yield stress, elastic modulus, surface absorption coefficient and thermal conductivity of the material incorporated with SiC particles, the effect of reinforcement on laser bending angle was analyzed, and it was found that it would result in a larger bending angle. The significance of the findings will be discussed in the paper. [Copyright &y& Elsevier]

Web-post buckling by shear is one of the typical failure modes of beams with sequential web openings, as well as the preponderant failure mode in fire. With the increase of the temperature, the modulus of elasticity of steel reduces faster than its resistance, so the beam becomes more susceptible to failure due to instability. This paper presents a comparison between existing formulations for determining the shear buckling strength of web-posts and validated numerical results. The objective was to assess if they are valid in fire conditions, with the modification of the modulus of elasticity and yield strength of steel according to each temperature considered in the analysis, using the statistical evaluation method present in EN 1990:2002. It was evident that the formulations analyzed are satisfactory at ambient temperature but most of them need adjustments when applied in fire. • Statistical analysis of design models, based on EN 1990:2002. • Comparison between validated numerical models and formulations adapted for fire. • Numerical and analytical results converge at ambient temperature. • For fire, there is a need for adjustments in most of the formulations analyzed. [ABSTRACT FROM AUTHOR]

Reinforced concrete coupled walls are widely used as the main seismic resistant structural system in high-rise buildings. This paper proposes a new mixed beam-shell model for the seismic analysis of reinforced concrete coupled walls with sufficient efficiency and accuracy on the platform of general finite element software MSC.Marc. Boundary elements at the ends of wall piers are simulated by conventional fiber beam-column elements, while the web of the wall pier is modeled by the layered shell element. Coupling beams are simulated by non-conventional fiber beam-column elements, which can not only take into account the shear and shear-sliding deformation together with various failure modes of conventionally reinforced beams, but also the shear and rebar slip deformation of diagonally reinforced beams. RBE2 link elements are utilized to connect the coupling beams to the wall piers. Eight test specimens reported in the literature are used to validate the proposed model. The mechanism of the coupled wall is thoroughly investigated in terms of the beam deformation, base shear and moment distribution as well as axial force of the wall piers. Furthermore, parametric analyses on specimens with different degrees of coupling and types of reinforcement layouts of coupling beams are conducted. Based on the analyses, the influences of the complex behavior and various modeling parameters of coupling beams on the behavior of coupled wall are revealed quantitatively. As a conclusion of the parametric analyses results, it is recommended that the complicated behavior of coupling beams be accurately considered for most cases in the seismic analysis of coupled wall systems. [ABSTRACT FROM AUTHOR]

High Pressure and High Temperature (HPHT) oil and gas pipelines are commonly buried subsurface and the depth of burial is determined by upheaval buckling mitigation requirement or legislation requirement. The upheaval buckling mitigation design requires evaluation of uplift resistance of soil in which pipeline is buried. Conventional design guidelines and current analytical models for predicting the soil uplift resistance are based on either dry soil or fully saturated soil. However, onshore pipeline are buried in soils which are often partially saturated. Therefore, current analytical models do not capture the effects of soil saturation on the uplift resistance of buried pipeline. In partially saturated soils, the uplift resistance is greater than that under fully saturated conditions. This is because the water meniscus between soil particles creates an additional normal force due to suction, which in turn makes the soil behaviour stiffer and stronger. This paper presents full scale pipe-soil tests results and finite-element parametric studies conducted to investigate the effects of soil moisture content, dimensionless cover heights (soil cover height to diameter ratio) and soil relative density on the peak uplift resistance of pipes. The results demonstrate that the current available analytical models under-predict the soil peak uplift resistance in partially saturated conditions. Further, the analyzed results are presented as dimensionless design charts and non-linear regression models which can be used to quantify the partial saturation effect on uplift resistance of buried pipes. [ABSTRACT FROM AUTHOR]

Hard structural elements in nature are often joined with sutures lines, as seen in human skull, cephalopods or turtle shell. These sutures can arrest cracks, and can provide flexibility for respiration, locomotion or growth. In this paper we introduce a morphometric method to capture the complex shape of sutured interfaces using only a few parameters. The method is simple, and can capture relatively complex suture geometries with re-entrants, interlocking features. The study starts with a simple jigsaw-like model which is enriched with additional features (plateau regions in dovetail-like sutures, multiple locking sites). For each case, closed form and finite elements solutions are developed to capture the full nonlinear pullout response and to predict the maximum stress (and potential fracture) in the solid material. These models were then used to identify the geometries and interface properties (friction) that lead to optimum combinations of strength and energy absorption. Suture designs that reduced frictional stress with low coefficient of friction or with multiple contact points were the most efficient. The results can serve as guidelines to design and optimization of non-adhesive sutures with arbitrary shapes made of arc of circles and lines. We found that the best designs involve low coefficient of friction, which raises an interesting hypothesis on the function of the protein layer in natural sutured lines: This soft layer could act as “lubricant” to prevent the fracture of the solid structures. [ABSTRACT FROM AUTHOR]

Pultruded carbon fibre reinforced polymer (P-CFRP), a polymer matrix composite material, has been increasingly used in industry, science, equipment and engineering in recent decades. In civil engineering, when a structure reinforced with pultruded carbon fibre reinforced polymer (P-CFRP) is subjected to fire, both the structure and the CFRP reinforcement are concurrently affected by elevated temperature (potentially up to 1200 °C according to the standard ISO 834-1) and mechanical load. This study focuses on characterization of the mechanical performance of P-CFRP under thermal action. In Eurocode, the mechanical properties of both concrete and steel are reduced as the temperature rises, but the performance of P-CFRP has not been clearly mentioned. This paper studies the evolution of the behaviour of P-CFRP through tensile tests addressing the impacts of elevated temperature (varies from 20 °C to 700 °C) and mechanical loading on the material. This study features two types of tests: the thermal mechanical tensile properties test and the residual tensile test. The results show that the P-CFRP has linear behaviour in each temperature condition for both test types and that the tensile properties including the tensile strength and modulus are generally reduced as the applied temperature increases from 20 °C to 700 °C. The results also show that the thermomechanical strength of P-CFRP is lower than its residual strength at the same level of applied temperature. The thermomechanical strength of P-CFRP was obtained with direct tensile test at an elevated temperature level (T) performed on P-CFRP specimen. The residual strength of P-CFRP was obtained with the tensile test at ambient temperature performed on preheated-cooled P-CFRP specimen that was preheated up to the same temperature level (T) and then progressively cooled until ambient temperature. In addition, the failure modes associated with the loading path and different temperature levels are identified. They provide the references to the thermomechanical state at which material failure happens. The experimental results are used to calibrate two prediction models, which can be applied to the thermomechanical estimation of structures reinforced with P-CFRP under different temperature and mechanical conditions . [ABSTRACT FROM AUTHOR]

The aim of analytical models presented in this paper was to provide a first set of data for choosing thermal conditions during thermoplastic injection molding. Two different models allowed the quick determination of the cooling/solidifying time, the mold surface temperature variation and the heat flux densities exchanged between the polymer and the mold. The first model specific to amorphous polymers was based on the 1D heat conduction equation. The second model dedicated to semi-crystalline polymer was based on the adaptation of the solution of the Stefan problem for part with a finite thickness. For each case, the influence of the thermal contact resistance between polymer and the mold on the cooling/solidifying time was highlighted. Then, the description of heat transfer in the mold allowed to determine the time needed to produce reliable parts when the mold was in periodic steady state. The attenuation of the periodic temperature variation through the thickness of the mold was evaluated through the penetration depth. Parameters calculated from these analytical models were compared with experimental results obtained with an instrumented mold or with data computed with a coupled model. The good agreement between them validated the interest to these models to get quickly reliable characteristic parameters of injection molding. [ABSTRACT FROM AUTHOR]

In the assessment of wood charring, it was believed for a long time that physicochemical processes were responsible for the creation of cracking patterns on the charring wood surface. This implied no possibility to rigorously explain the crack topology. In this paper we show instead that below the pyrolysis temperatures, a primary global macro-crack pattern is already completely established by means of a thermomechanical instability phenomenon. First we report experimental observations of the crack patterns on orthotropic (wood) and isotropic (Medium Density Fibreboard) materials in inert atmosphere. Then we solve the 3D thermomechanical buckling problem numerically by using the Finite Element Method, and show that the different crack topologies can be explained qualitatively by the simultaneous thermal expansion and softening, taking into account the directional dependence of the elastic properties. Finally, we formulate a 2D model for a soft layer bonded to an elastic substrate, and find an equation predicting the inter-crack distance in the main crack-pattern for the orthotropic case. We also derive a formula for the critical thermal stress above which the plane surface will wrinkle and buckle. The results can be used for finding new ways to prevent or delay the crack formation, leading to improved fire safety of wood-based products. [ABSTRACT FROM AUTHOR]

Mobile computing devices have improved substantially. Such a development fosters the usage of those devices for various purposes, including health care as a prominent example. Mobile health (mHealth) is a subfield of electronic health (eHealth) that refers to the practice of medicine and public health supported by mobile devices. A specific concern for mHealth is the limitation of power supply for the mobile devices, since interruptions on power supply can result in critical situations. This paper proposes analytical models to identify the mean time of one life cycle of the battery, and thus identify the average battery lifetime considering some device utilization characteristics. We evaluate the impact of both network connectivity (local and wide areas) and communication protocols (Polling, Long polling, WebSockets, and XMPP) on the discharging rate, and subsequently on the lifetime of batteries with different power capacities. We observed a noteworthy impact of these factors on battery usage and, thus, on mHealth applications. We use a hierarchical modeling approach that enables efficient representation of system complexity and provides accurate results for planning the autonomy of mobile devices in an mHealth context. [ABSTRACT FROM AUTHOR]

A new analytical approach able to predict the mechanical behavior of rock bolts subjected to pull-out tests was proposed in this paper. Input parameters of such approach are: rib profile shape, height, width, angle of wrap and spacing, axial bolt pull-out force, and material properties. As for the analytical part, the basis of the new analytical solution for the prediction of the load displacement curve was developed. Derived mathematical equations enable calculations of grout displacement in elastic and elasto-plastic behaviour. In the experimental part, four examined bolts in situ pull-out tests were compared with the predictions of the new analytical approach, and this comparison led to the validation of this approach. [ABSTRACT FROM AUTHOR]

Despite the increasing use of pultruded glass fibre reinforced polymer (GFRP) profiles in civil engineering structural applications, most common beam-to-column connection systems still mimic those used in steel frame structures, not accounting for the inherent differences of mechanical properties between the GFRP and steel. Therefore, due to the low transverse modulus and strength of GFRP profiles, these connection systems have several limitations in terms of stiffness and load carrying capacity. This paper presents the development of an innovative beam-to-column bolted connection system for GFRP tubular profiles comprising tailor-made steel connection parts that are positioned inside the GFRP sections. The experimental investigations first included double-lap tests to characterize the behaviour of bolted connections between GFRP and steel plates. Next, tests were performed on full-scale beam-to-column connections using the novel connection system, in which the following configurations were assessed: (i) one bolt per web (W1), (ii) two bolts per flange and short edge distance (F2), (iii) two bolts per flange and long edge distance (F2S), and (iv) four bolts per flange (F4). Results showed that the stiffness of the connection system is mainly influenced by the number of bolt rows, while the strength depends on the bolt edge distance – the maximum stiffness and strength were provided by configurations F4 and F2S, respectively. Moreover, with these configurations it was possible to obtain a pseudo-ductile failure behaviour. The stiffness of each connection type was estimated with reasonable accuracy using the “component method”. On the other hand, estimates of the failure load using the same method and the available design guides were non-conservative and presented poor correlation with the test results, suggesting the occurrence of mechanisms more complex than those considered to estimate the loads. Therefore, numerical models were developed to estimate the stress resultants in the bolts, which allowed to predict the strength of the connection series. [ABSTRACT FROM AUTHOR]

Near-threshold operation is garnering growing attention for ultra-low power applications despite the fact the reliability of the near-threshold digital systems warrants unprecedented scrutiny of robustness measures to ensure correct functionality under stringent environmental and manufacturing scattering specifications. In this paper, an ideal theoretical read and write static noise margins (RSNM/WSNM) are discussed. In addition, a 12T SRAM bit cell is proposed in order to reach the theoretical WSNM limit. This could be achieved by eliminating a feedback of back-to-back inverters by means of data-dependent supply cutoff during write operation. This allows the proposed bit cell to enlarge write margin dramatically. Many previous works also attempt to cutoff the supply, but many of them were not data dependent. Monte-Carlo (MC) simulation results show the proposed 12T SRAM bit cell is more robust in static and dynamic noise margin than the conventional 6T and 8T SRAM bit cells as well as a 10T bit cell. The area overhead of the proposed bit cell is 1.96 times and 1.74 times greater than the 6T and 8T bit cells, respectively. Analytical models of WSNM for the 12T bit cell in the super-threshold region and the sub-threshold region are also proposed. [ABSTRACT FROM AUTHOR]

Composite sandwich structures made of thick glass face sheets adhesively-bonded to glass fibre-reinforced polymer (GFRP) core profiles have the potential to outperform existing non-composite glazing configurations but their feasibility has yet to be investigated and there are no analytical models that describe their structural response. This paper presents the new analytical models for predicting deflections and strains in adhesively-bonded GFRP-glass sandwich beams. The new analytical models successfully account for: the shear deformations of the core and adhesive layers; the local bending of the constituent parts about their centroidal axes; and the global bending of the sandwich component as a whole. The deflections and strains predicted by analytical models are validated by finite element simulations and compared with the results of destructive tests performed on adhesively-bonded GFRP-glass beams in a four-point bending configuration. The analytical models were also evaluated for alternative GFRP-glass configurations tested by others. The GFRP-glass beams specially assembled in this study confirm the physical feasibility of constructing these proposed components. [ABSTRACT FROM AUTHOR]

This paper presents a new steel–concrete–steel sandwich panel with interlocked angle connectors (SCSP-IACs), and its punching performances were experimentally and analytically studied. Nine SCSP-IACs were fabricated and tested under the out-of-plane patch loads. Test results showed that SCSP-IACs exhibited two types of load–deflection (P – δ) responses with the variation of spacing of IACs (S), and increasing S also showed significantly negative influences on their punching behaviors. Two peak resistances were observed from the P – δ curves of all SCSP-IACs, and the first and second peak resistances (P u1 and P u2) corresponded to the punching shear failure of the concrete core and top steel faceplate, respectively. The punching shear resistance of SCSP-IACs was found to be evidently improved with the increase of steel faceplate thickness (t s) and concrete core thickness (d), while increasing S led to the decrease of punching shear resistance of SCSP-IACs. Moreover, the interlocking bolt in IACs exhibited little influence on the punching behaviors of SCSP-IACs. Finally, analytical models were proposed for calculating the punching shear resistance of SCSP-IACs, and their accuracies were also verified with test data. • A novel steel–concrete–steel sandwich panel with interlocked angle connectors (SCSP-IACs) was proposed. • The influences of variant parameters on punching behaviors of SCSP-IACs were studied. • The punching shear failure criterion of the SCSSP-IACs under out-of-plane patch loads was revealed. • Analytical models were developed to predict the punching shear resistance of SCSP-IACs. [ABSTRACT FROM AUTHOR]

This paper firstly developed high performance sandwich composite beams with novel J-hooks and ultra-high performance concrete (UHPC), i.e., steel-UHPC-steel sandwich composite beams with J-hooks (SUSSBJs). Nine full-scale two-point loading tests were then performed on SUSSBJs to study their ultimate strength behaviour. The test results revealed that all SUSSBJs exhibited flexural failure even for SUSSSBJs with short shear span ratio of 2.41 and high spacing of J-hooks of 200 mm due to the high performance UHPC. The test results showed the SUSSBJs exhibited a four-stage working mechanism, which were initial elastic, elastic, nonlinear developing, and hardening stage. The test results also detailed reported and discussed the influences of key parameters on flexural behaviour of SUSSBJs. The flexural bending resistance of SUSSBJs was reduced for small shear span ratios; the spacing of J-hooks did not change the flexural failure mode, but reduces its ultimate strength as well as working mechanism; and all the strength and stiffness indexes increase linearly with the increasing thickness of faceplate. Finally, this paper developed analytical models on stiffness and strengths indexes of SUSSBJs, and the validations against nine test results proved their capabilities on predicting these indexes. • High performance steel-UHPC-steel sandwich structures with J-hooks (SUSSSJ) are developed • Flexural behavior of SUSSSJs are studied through nine four-point bending tests • Key parameters influencing structural behaviours of SUSSSJs are revealed • Developed theoretical models predict well strength and stiffness of SUSSSJs [ABSTRACT FROM AUTHOR]

• This paper introduces a simplified analytical modeling approach for RMSWs. • Modeling approaches for both individual RMSWs and systems of RMSWs are presented. • Developed analytical models are verified using experimental results. • Factors affecting accuracy of developed modeling approach are discussed. • A parametric study was carried out to investigate parameters of systems of RMSWs. This paper presents a simplified analytical approach for modeling the behavior of both individual reinforced masonry structural walls (RMSWs) (component level) and systems of RMSWs as the main lateral load resistance system (LLRS) (system level) under lateral loading. Analytical modeling of individual RMSWs, with different end configurations (rectangular, flanged & end-confined), was achieved by generating the load-displacement relationships for these walls based on simple mechanics and accounting for plastic hinging. Knowing that plastic hinging is concentrated at the base of cantilever structural wall, its value was estimated based on experimental results and plasticity theory, taking into consideration the effect of strain penetration inside concrete foundation, inclined flexural-shear cracking and variation of curvature profile following yielding. Also, analytical modeling of a system of RMSWs may be conducted and the displacement of each wall can be calculated by simple geometrical relations, if the displacement of the center of mass (CM) and the rotation angle of the building are known. Results of some experimental tests were used to verify the results of the developed analytical models for individual RMSWs. The maximum error obtained in all models at maximum load, deformation at maximum load and deformation at 80% strength degradation, compared to experimental results, were 8.05%, 8.55% and 9.87% respectively. A third-scale building composed of several RMSWs as its main LLRS was used to verify the developed analytical algorithm for a system of RMSWs and the results showed that the value of building resistance was lower than the average value between push and pull cycles from experimental results by 7.38%. The analytical algorithms developed for both individual RMSWs and systems of RMSWs throughout this study were simply relying on analytical application program. As a result, better understanding of the behavior of systems of RMSWs when subjected to seismic loads can be achieved. The factors affecting the accuracy of the developed modeling technique are presented and discussed in this paper. Recommendations for problems faced through developing this modeling technique and the governing factors are presented throughout this study. Based on the analytical verification presented, a parametric study was carried out to investigate the effect of different parameters as lateral load eccentricity, torsional effects, and presence of walls orthogonal to the loading direction. [ABSTRACT FROM AUTHOR]

This paper firstly proposed steel-concretes-steel sandwich walls with J-hook connectors (SCSWJs) as protective structures in the Arctic offshore platforms. Followed, six large scale SCSWJs were tested under lateral cyclic loading to investigate their lateral seismic behaviours. The investigated parameters in the testing program included spacing of J-hook, concrete core strength, thickness of steel faceplate, and aspect ratio. Seismic behaviours of SCSWJs were reported in details, and the effects of these parameters on their seismic behaviours were reported and discussed. The test results showed that the SCSWJ failed in flexure mode with characteristics of tensile yielding of side plate and steel faceplate, concrete crushing at the bottom toe, and outward local buckling of steel faceplates. Pinching effect was observed in the load versus lateral drift curves after the peak load due to premature local buckling of side plates and faceplates locating between the first and second row of J-hook from the bottom. This paper developed analytical models to predict the peak lateral resistance of SCSWJ. The validations against 12 results from six cyclic tests confirmed that the developed models offered reasonable but conservative predictions on the peak lateral resistance of SCSWJ. This study promotes the applications of the SCSWJ in the earthquake-prone Arctic regions. • Novel SCS sandwich walls with J-hook have been proposed for civil and offshore structures. • Seismic behaviors of novel SCSWJ shear walls are evaluated by large-scale tests. • Key parameters influencing seismic performances of SCSWJ are studied and reported. • Analytical models are developed for ultimate lateral shear resistance of SCSWJ. [ABSTRACT FROM AUTHOR]

The enhanced oil recovery is applied to increase oil recovery from oil reservoirs. The immiscible CO 2 injection oil recovery method is suitable for reservoirs with low pressure. This paper presents a review of literature focusing on CO 2 injection by focusing on three aspects. First, screening reservoir parameters are reviewed to assess their practicality for immiscible CO 2 injection. These criteria are also used to deduce the governing reservoir parameters included in the analytical model to calculate the oil recovery factor. Second, analytical models used for oil recovery using reservoir parameters and operational variables are reviewed. Third, the criteria for choosing parameters to be included in the analytical model are discussed. Researchers have proposed reservoir permeability, reservoir porosity, oil density, oil viscosity, the interfacial tension between oil and CO 2 , injection pressure, and Darcy's velocity as critical parameters in the analytical model for oil recovery calculations. The research gaps and future research direction are also discussed. • Oil recovery can be enhanced through immiscible CO2 injection. • Reservoir screening determines the practicality of immiscible CO 2 injection. • Analytical models use reservoir and operational parameters to predict oil recovery. • Using additional parameters can help in better prediction of oil recovery. [ABSTRACT FROM AUTHOR]

A semi-analytical model for a naval shock problem is proposed in this paper. It is applied to calculate the signals and response spectra which characterize the dynamic response of submarine hulls bearing equipment, when the latter is subjected to a pressure wave triggered by a far-field underwater explosion. It is also used to compare the configurations in which the hull may be filled or not with an inner fluid. The proposed model corresponds to a simplification of actual configurations, in the sense that the hull is simplified to a cross-section of a circular cylinder and that the equipment is simplified to a mass point. However, it allows to derive meaningful data – in particular the spectral response of the equipment and associated design shock response characteristics – which are representative of naval shock environment and useful for architects as design values in the early stages of naval projects. The details of the mathematical model are exposed, together with data validating them. The model proves useful to highlight the parameters of primary importance for the physics at stake and to investigate their influences on the acceleration and velocity levels of both the hull and the on-board equipment. Simple mathematical expressions are derived, and may prove useful for designers. • Semi-analytical models prove useful to derive data describing UNDEX. • Existing models – e.g. rigid cylinder – have been extended to address a wider range of configurations in UNDEX problems. • Shock signals on immersed surfaces as well as response of simple systems attached to them is calculated. • The influence of submergence conditions on the response to UNDEX is investigated and evidenced. [ABSTRACT FROM AUTHOR]

In this paper, the results of pilot experiments carried out on glass columns are presented and critically discussed. The aim of this preliminary experimental study consists in the verification and assessment of the actual global behaviour of monolithic glass columns with square hollow cross-section under axial compression, as well as in the estimation of the compressive loading ratios leading to the opening of first cracks and collapse of the same specimens, respectively, together with the corresponding failure mechanisms. In order to properly interpret the obtained test results, the experimental predictions are first compared and assessed towards analytical calculations (e.g. in terms of Euler’s buckling load) and Finite-Element (FE) models later (e.g. in the form of load–displacement response). In the first case, classical analytical formulations not able to take into account the effects deriving from a combination of several aspects (e.g. possible initial geometrical imperfections in each glass pane or in the assembled square hollow section, load or boundary eccentricities, as well as the actual bonding effect of the glued joints connecting the glass components) typically result in a marked overestimation of the actual load bearing capacity for the tested columns, hence suggesting more refined investigations. Rather close agreement is found in fact with properly assembled fully 3D solid FE models. In them, a key role is assigned to the geometrically refined description of each specimen component (including the glued joints and the end restraints), as well as to the accurate mechanical calibration of the materials, based also on further experimental tests carried out on small adhesive specimens. Finally, the feasibility and accuracy of simplified 2D FE-models – less time consuming than fully 3D assemblies – is also assessed, so that practical recommendations could be provided. In the latter case, as shown, higher sensitivity of FE results to the main input parameters is found, with consequent underestimation of the actual elastic resistance for the tested columns. Based on the current comparisons and findings, however, it is expected that the current research outcomes could be further extended to various glass columns typologies and configurations (e.g. including laminated glass specimens and several cross-sectional shapes, as well as full-scale experiments), in order to develop appropriate practical design rules. [ABSTRACT FROM AUTHOR]

The paper presents the outcome of a research on the in-plane behaviour of two different log house construction systems when subjected to lateral loading. Such systems, identified by the way the logs are joined together are: the Standard half lapped joint (ST) system and Tirolerschloss joint (TR) system. Two stages of experimental testing were carried out at the laboratory of the University of Trento. In the first stage the focus was on the corner joints and on a possible wall reinforcement system (22 monotonic and 5 cyclic tests were performed). In the second stage full-scale wall specimens were tested (5 monotonic and 5 cyclic tests). Several layouts were investigated: 4.2 m long walls with thin (TR and ST) or thick logs (ST); “short” walls (2.75 m long); walls with openings. The test results highlighted some critical aspects in the in-plane behaviour of the walls. The lateral load carrying capacity of the wall appeared to be influenced by two main phenomena: friction and corner-joint interlocking. Due to mounting tolerance a large displacement was required to fully engage the corner joint resistance. A large horizontal plateau characterized the post friction part of the load displacement curve (wide plateau) both for ultimate limit state (ULS) and serviceability limit state (SLS). The cyclic tests showed a high level of energy dissipation that was attributed to the “inter-log friction”. In order to have a better insight into such aspects, a simplified rheological/analytical model was developed by using the experimental data as input parameters. A good agreement between the model output and the experimental behaviour was obtained. [ABSTRACT FROM AUTHOR]

In the present work the unsteady numerical simulation of a solar domestic hot water (DHW) system composed of two flat plate collectors, a water tank for heat storage, and a coil heat exchanger is addressed. The simulations have been performed using two different solvers, namely a home-made code written in Matlab, and TRNSYS 17. In the first part of the paper, the analytical models used in the Matlab code, and the TRNSYS case are reported in detail. Successively, the results of the simulations realized by means of the two solvers are presented and compared. [ABSTRACT FROM AUTHOR]

The use of Acoustic Emission (AE) signal of scratch test to evaluate the thin films' adherence led to unavoidable large uncertainties due to the problematic determination of the frequency band and the improper installation of the acoustic sensor, especially for coatings thinner than 100 μm. In this paper, thin film–substrate adherence in high-speed steel is evaluated by Wavelet Analysis (WA) of the force–displacement curve in micro-scratch tests performed on the samples. The measured load displacement signals of deposited thin films were used as inputs for the wavelet module. We propose an analytical model combined with wavelet analysis, which is based on experimental data. Scratch adhesion strength could be identified by applying wavelet technique to the measured force displacement data to detect the location of the critical load during micro-scratch testing for TiSiN coating on high-speed steel. An analytical model is also proposed to predict the adhesion stress and to support the wavelet analysis technique where the stress is difficult to be assessed. Thin films were studied by optical microscopy, micro scratch testing machine and X-ray diffraction. The WA results are compared with model predictions in order to establish indication of scratch adhesion strength aimed at improving the manufacturing process. [ABSTRACT FROM AUTHOR]

Blockhaus structural systems are obtained by assembling multiple timber logs able to interact with each other by means of simple mechanisms (e.g. contacts, tongues and grooves, and carpentry joints, also referred to as ‘corner’ joints). Although these systems have ancient origins, the structural behaviour of Blockhaus systems under well-defined loading and boundary conditions is still complex to predict. The paper focuses on the assessment of the typical buckling behaviour and resistance of in-plane compressed timber log-walls. The effects of various mechanical and geometrical aspects such as in-plane rigid inter-storey floors, load eccentricities, different types of lateral restraints, openings (e.g. doors or windows) or additional metal stiffeners, are investigated by means of full-scale buckling experiments. Results are then critically discussed and preliminarily assessed via analytical formulations taken from classical theory of plate buckling and column buckling. Although further advanced studies are required for the development of a generalized buckling design method, it is shown that several mechanical and geometrical aspects should be properly taken into account to correctly predict the structural capacity of Blockhaus systems under in-plane compression. [ABSTRACT FROM AUTHOR]

The state-of-the-art mass sensing so far has been rather developed along the resolution axis, reaching atomic-scale detection, than into the direction of high-speed. This paper reports a novel self-calibrating technique, making high-speed inertial mass sensors capable of instant high-resolution particle detection and weighing. The sensing nanoelectromechanical resonator is embedded into a phase-locked loop and the sensor-inherent nonlinear phase–frequency relation is exploited for auto-calibration. A tunable on-chip carbon nanotube based mass balance serves as a case study of small-size and low-cost environmental and healthcare applications. Tunability and a phase-locked loop topology make the system widely universal and invariant to nanotube characteristics. Operational for tube eigenfrequencies up to 385 MHz, the circuit integration in a 180 nm technology achieves instantaneous zeptogram resolution, while yoctogram precision is obtained within the tenth of a second. These figures of merit range at the physical limits of carbon nanotube resonators, in both mass- and time-resolution. [ABSTRACT FROM AUTHOR]

This paper presents an evaluation of Scenarios for constrained and unconstrained airport growth. These Scenarios are characterized by profits and costs relevant for particular actors/stakeholders who are directly and indirectly involved. The profits are those of the air transport industry (airports, airlines, and ATC (Air Traffic Control)) and the society. The costs are those of the impacts on the society and environment, internalized as externalities mainly affecting the nearby (local, regional) communities. For this purpose, a methodology consisting of analytical models for estimating particular profits and costs/externalities of the specified Scenarios of growth and a CBA (Cost Benefit Analysis) for evaluating these Scenarios was developed and applied using the inputs from a large European airport. This particular airport has been facing the issue of choosing between the two above-mentioned Scenarios for a long time. The results indicate that the constrained growth in the medium- to long-term is more feasible if the airport cannot provide subsidies for investments into the airside infrastructure (in this case - a new runway). The aviation industry (airport, airlines, ATC (Air Traffic Control)) and the society as well can generally benefit from the unconstrained airport growth. Nevertheless, the overall social-economic feasibility of the Scenario of unconstrained growth in the given airport case was shown to be marginal compared to its counterpart - Scenario of constrained airport growth. • Defining mutually-exclusive Scenarios for constrained and unconstrained airport growth; • Developing a methodology for evaluation of the specified Scenarios of airport growth; • Applying the methodology to a large European facing with the challenge of constrained and unconstrained growth. [ABSTRACT FROM AUTHOR]