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The pulsatile properties of arterial flow and pressure have been thought to be important. Nevertheless, a gap still exists in the hemodynamic effect of pulsatile flow in improving blood flow distribution of veno-arterial extracorporeal membrane oxygenation (VA ECMO) supported by the circulatory system. The finite-element models, consisting of the aorta, VA ECMO, and intra-aortic balloon pump (IABP) are proposed for fluid-structure interaction calculation of the mechanical response. Group A is cardiogenic shock with 1.5 L/min of cardiac output. Group B is cardiogenic shock with VA ECMO. Group C is added to IABP based on Group B. The sum of the blood flow of cardiac output and VA ECMO remains constant at 4.5 L/min in Group B and Group C. With the recovery of the left ventricular, the flow of VA ECMO declines, and the effective blood of IABP increases. IABP plays the function of balancing blood flow between left arteria femoralis and right arteria femoralis compared with VA ECMO only. The difference of the equivalent energy pressure (dEEP) is crossed at 2.0 L/min to 1.5 L/min of VA ECMO. PPI’ (the revised pulse pressure index) with IABP is twice as much as without IABP. The intersection with two opposing blood generates the region of the aortic arch for the VA ECMO (Group B). In contrast to the VA ECMO, the blood intersection appears from the descending aorta to the renal artery with VA ECMO and IABP. The maximum time-averaged wall shear stress (TAWSS) of the renal artery is a significant difference with or not IABP (VA ECMO: 2.02 vs. 1.98 vs. 2.37 vs. 2.61 vs. 2.86 Pa; VA ECMO and IABP: 8.02 vs. 6.99 vs. 6.62 vs. 6.30 vs. 5.83 Pa). In conclusion, with the recovery of the left ventricle, the flow of VA ECMO declines and the effective blood of IABP increases. The difference between the equivalent energy pressure (EEP) and the surplus hemodynamic energy (SHE) indicates the loss of pulsation from the left ventricular to VA ECMO. 2.0 L/min to 1.5 L/min of VA ECMO showing a similar hemodynamic energy loss with the weak influence of IABP.

To investigate the axial compressive behavior of an opening cold-formed thin-wall C-steel combined double-limb column, C-steel combined I-section columns were modeled in this paper, and the models were validated by experiments on axial-compressed combined columns. Parametric analyses were carried out on the combined columns. The effects of slenderness ratio, height to thickness ratio, width to thickness ratio, bolt spacing, and opening in the web on the ultimate compressive bearing capacity of the combined columns were investigated. It was observed that the slenderness ratio had the most significant effects on the combined column. Furthermore, the formulas predicting the compressive bearing capacity in the Chinese and AISI standards were compared, and the accuracy of the formulas was studied. Afterward, the formulas with higher accuracy and applicability for the ultimate compressive bearing capacity for the C-steel combined I-section column were proposed. The compression stability factor and reduction factor were fitted in this paper. The proposed formulas and factors can predict the ultimate compressive bearing capacity of the C-steel combined I-section column.

The use of cold-formed steel (CFS) members in structural engineering has been on the increase recently due to a wide range of benefits. The placement of electrical and/or plumbing installations within the floor or wall thickness requires that members are being manufactured with holes along the web, inevitably affecting their resistance. This article aims at providing a useful and comprehensive overview of the existing literature regarding CFS members with web holes. Experimental and numerical research on CFS members with web holes subjected to pure compression, bending, web crippling and shear is outlined and discussed. Although research on these types of members date back to the early 1970s, the greatest progress in the research field of CFS members with web holes was achieved during the past 15 years; hence, mostly the research conducted during this period was addressed. Additionally, design proposals are summarised for each of the aforementioned stress states. A brief description of the main concepts of design presented in four principal design codes, as well as numerical solution methods for predicting global, local, and distortional buckling modes, is also presented, aiming to collect the accessible up-to-date knowledge of CFS members with holes and identify areas that were modestly covered by previous research.

We studied the site ecology of Salvia brachyodon (Lamiaceae), a narrow endemic of the eastern Adriatic, which is now restricted to only three sites, using the sigmatistic method and numerical analyses. Four floristically and ecologically well-defined groups of stands, representing different syntaxa, were identified, corresponding to the sampling sites. The majority of stands represent dry eastern (sub)Mediterranean rocky grasslands at different successional stages towards (sub)Mediterranean forest vegetation. Compared to the evolutionary and ecologically closely related and sympatric S. officinalis, the morphologically easily distinguishable S. brachyodon differs in its flowering phenology and prefers relatively cooler, wetter, deeper and nutrient richer soils, which are developed on dolomite or dolomitic limestone at higher elevated sites. Despite its ability to cope with interspecific competition by means of clonal reproduction better than its congener, the populations are severely threatened by abandonment of traditional land use and by fires, making the species endangered (EN) according to IUCN criteria. [ABSTRACT FROM AUTHOR]

Geocells are three-dimensional cellular expandable mats used to improve the load-carrying capacity of weak subgrades. The expanded geocell pockets take the shape of a honeycomb connected to their neighbouring pockets. This manuscript deals with the importance of considering the exact shape of the geocell pockets in three-dimensional numerical modelling. The data for the calibration of the numerical models was obtained through laboratory plate load tests. The numerical simulations were carried out using finite difference software, Fast Lagrangian Analysis of Continua in Three Dimensions (FLAC3D). The walls of the geocell were modelled using geogrid elements having only tensile load capacity. The interfaces between the geocell walls and the infill soils were modelled using Mohr-Coulomb yield criterion. Three shapes of geocell pockets, viz. an exact honeycomb shape and simplified shapes (square and diamond), were considered in the numerical simulations. The numerical models with an exact shape of pockets have shown better agreement with experimental data, while the models with approximated shape overestimated the actual load capacity. The paper describes the modelling approach and the reasons for more accurate numerical predictions with the exact shape of geocell pockets compared to simplified pocket shapes. [ABSTRACT FROM AUTHOR]

Until now, some test specimens with different shapes and loading mechanisms have been utilized for investigating the cracking behavior of adhesive bounded joints. In this research, using a novel test configuration called adhesive short bend beam specimen containing an inclined crack and loaded by three-point bending, mixed mode I/II fracture parameters of a crack initiated in the adhesive part is studied. Compared to other test methods, the specimen used in this research needs a lesser amount of material and the fracture test can be performed easily. A large number of finite element models of this specimen were analyzed using ABAQUS code to study the effect of adhesive and adherent type, and also the crack length and loading span distance on KI, KII, T-stress and fracture initiation direction under different mode mixities. The results showed that the fracture parameters (and in particular the shear mode component) are sensitive to the type and location of adherent in the bounded joint; however, the shape and size of fracture plastic zone is not affected noticeably by the type of adhesive-adherent materials. It was also shown that the complete mode mixities ranging from pure mode I to pure mode II can be introduced for adhesive bounded joints using the proposed test specimen and therefore the specimen is a good candidate test configuration for investigating the mixed mode I/II fracture behavior of adhesive bounded joints. [ABSTRACT FROM AUTHOR]

Numerical simulations are performed to study the behavior of hypothetical one, two, and three-story structures when different earthquake conditions occur in a selected soil profile in the southern California. Computed performance of the low-rise structures is assessed including substructure modeling of basement levels in numerical simulations. The numerical simulations showed the relationship between number of stories, peak ground acceleration, ground surface settlements, and horizontal peak story accelerations induced by the earthquakes and the computed performance of hypothetical structures built on liquefiable soils. The results suggest that the inclusion of basement levels positively influenced the overall seismic performance of low-rise structures. [ABSTRACT FROM AUTHOR]

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The article presents the results of a dynamic resistance analysis of selected existing bridge structures. The numerical calculations performed with the use of THA (time history analysis) pertained to road and rail bridges of steel and concrete structures—not paraseismically designed. The purpose of the work was to determine the dynamic resistance of objects to the influence of paraseismic impacts resulting from mining operations. The specificity of performing calculations in this area of engineering issues is presented. Real mining tremor signals, registered in the vicinity of the objects were used in the numerical analyses. The correct determination of the dynamic resistance of the object can be used as a basis for performing repair/strengthening of existing objects, which in the future will be loaded with additional paraseismic influences. [ABSTRACT FROM AUTHOR]

The ballast used in ballasted railway tracks transmits load from the rails and ties to the subgrade during train travel, and directly affects the overall track support performance and elastic behavior of the ballasted track. Due to the material limitations of the ballast, it is difficult to quantitatively manage its performance, status, and shape maintenance, and the use of the ballast requires continuous maintenance and management work. In this study on a proposed ballast material, ballast box tests and numerical analyses were performed to examine the performance of the ballast that has a gravel coating layer and can be used semi-permanently while maintaining the shape of the ballast against impacts, abrasion, and friction. The results show that the coated ballast’s performance ensured constant stiffness in comparison to that of a normal ballast.

In Hong Kong, design practice adopts the hydrodynamic load model to estimate the dynamic soil debris impact load on reinforced concrete debris-resisting barriers. A dynamic coefficient of 2.5 is empirically adopted, which takes into account the effect of the impact of boulders up to 0.5 m in diameter. With a view to rationalising the design of reinforced concrete debris-resisting barriers, the Geotechnical Engineering Office (GEO), in collaboration with the Hong Kong University of Science and Technology (HKUST), initiated a study to investigate the dynamic impact of soil debris. In particular, a series of large-scale impact tests using 4 m3 realistic debris mix and a 1.8-m-high reinforced concrete model barrier were conducted in the flume facility in the Kadoorie Centre in Hong Kong. The tests were well controlled, and the flow kinematics, including flow depth and flow speed, and the time history of the impact load at the wall stem subject to the debris impact were measured, which provided critical test data on assessment of the hydrodynamic load of soil debris hitting reinforced concrete structures. The scale of these physical impact tests under such a controlled environment was unique as compared with other studies in the literature. To further examine the dynamic impact force, a calibrated numerical model using a three-dimensional finite-element computer package, namely LS-DYNA, was adopted to simulate the impact scenario for a real-scale debris flow event of 400 m3, where an arbitrary Lagrangian-Eulerian technique was adopted to simulate debris materials. Based on both the experiments and numerical analyses, debris run-up along the wall stem was observed when the debris hit the model barriers. Under the experimental setting, the hydrodynamic soil debris pressure coefficients were consistently found close to unity, which are generally in line with that used in overseas technical guidelines or design practice. This study enhances fundamental understanding of the soil debris impact mechanism on reinforced concrete barriers and provides scientific evidence to rationalise the design guidelines used in Hong Kong. [ABSTRACT FROM AUTHOR]

In the literature, records and analyses have shown that in earthquake-prone areas local site conditions tend to alter the strong motion at the ground surface. More specifically, the surface topography, in combination to the soil stratigraphy and/or the geomorphology of the seismic bedrock, may have a substantial impact on the amplitude, the frequency content, and/or the duration of the seismic motion at the ground surface. The current study is involved with the Athenian Acropolis Hill, which is an unusual case of local site conditions affecting ground motion as a rock outcrop of limestone overlies the relatively soft Athenian schist. Since monuments of paramount importance are founded on the Hill (i.e. Parthenon, Propylaea, Erechtheion and Temple of Athena Nike) and Athens is characterised by moderate to high seismicity, a seismic array of accelerographs has been installed by the National Observatory of Athens and the Acropolis Restoration Service at specific locations on the Hill in order to monitor its seismic response in real time. Aiming to assess the impact of local site conditions on the seismic response of the Hill, an evaluation of the available recorded acceleration time histories has been conducted. Additionally, two-dimensional numerical simulations have been performed utilising the finite-element method. Various excitations, such as simple pulses and records obtained by the seismic array, have been used as input motion for the numerical analyses. Despite the discrepancies, the numerical results are in good agreement with the available records and demonstrate the importance of local site conditions on the seismic response of the Acropolis Hill. [ABSTRACT FROM AUTHOR]

Energy recovery ventilators (ERVs) are used to recover sensible and latent heat to reduce the heating and cooling load caused by outdoor air intake into indoor environments. The efficiency of the heat exchanger, comprising flow channels and constituent materials, determines the heat exchange performance of the ERV. Understanding the heat and mass transfer mechanisms in the ERV and optimizing the geometry and materials of the flow channel are essential for improving the ERV performance. Herein, numerical methods for predicting and clarifying the hygrothermal transfer mechanism in the heat exchange element of an ERV were developed, and their prediction accuracy was confirmed by analysing the exchange efficiencies in the scaled-down ERV unit model. The verified numerical model was applied to sensitivity analyses to clarify the rate-limiting factors influencing the total heat exchange efficiency of the ERV. Our findings have clarified that under Japan Industrial Standard cooling conditions, a 50-fold increase in the thermal conductivity of the spacer plate, the total heat recovery performance was enhanced by 13%, as for a 2-fold increase in the moisture conductivity, the performance was enhanced by 20%. The findings of this research can be expected to contribute to the energy saving effect in buildings. [ABSTRACT FROM AUTHOR]

Hydrodynamic lubrication of rectangular micro-textures on sliding contact surfaces is investigated using numerical calculation methods. The theoretical models for the slider surface are developed and the film pressure is used to evaluate the hydrodynamic lubrication based on the Reynolds equation. Meanwhile, the geometry and distribution of the rectangular dimples are optimized for maximizing the average film pressure. Results show that the film pressure is dependent on the geometry and distribution of the rectangular micro-dimples. The optimal geometry of the single rectangular dimple is obtained, and the spacing has an important influence on the film pressure. The distribution types of rectangular dimples affect the hydrodynamic lubrication significantly and the interlaced array of the rectangular micro-dimples is beneficial to enhancing the hydrodynamic lubrication. Meanwhile, the rectangular dimples with 72° interlaced angle exhibits the best effectivity. [ABSTRACT FROM AUTHOR]

Aizoaceae is one of the most important and widespread succulent plant families in both tropical/subtropical regions and arid zones. In this study, 27 species were collected from various floristic regions in Egypt, Kingdom of Saudi Arabia and cactus farms (Kalupia – Egypt). The morphological characteristics of every taxon were recorded. The important morphological features included: the number of leaves per plant; leaf types; leaf position (cauline or radical; the latter indicates leaves arising from, or near, the roots); leaf arrangement; petiolate or sessile leaves; leaf sheath present or absent; leaf shape; leaf margin; leaf tip; presence of leaf 'window area'; leaf texture; and presence of white or dark miniscule dots (white miniscule dots from calcium carbonate and dark miniscule dots from tannin sacs). The investigated anatomical features were as follows: shape of the transverse section; the type of epidermal cells; the presence of large epidermal cells (bladder cells); presence of papilla and simple hairs; presence of tannin sacs; shapes of calcium oxalate crystals; shape of the xylem vessels; and the presence of Kranz unit (the unit that constitutes the vascular bundle/s, parenchyma sheath, and surrounding mesophyll) or collenchyma sheath. All data were recorded in a data matrix (as either text or numerical data), which was used to construct the identification key and phylogeny tree using a multi-variate statistical package. The results of our analysis may open the possibility of using the morphological and anatomical features of leaves to distinguish between the subfamilies, genera, and species of Aizoaceae. [ABSTRACT FROM AUTHOR]

Miniaturization and on-chip integration are major lines of research in many branches of science and technology developments, undoubtedly in sensor technology. Fluxgate magnetometers are very sensitive, and accurate magnetic sensors able to detect weak fields both AC and DC, which in recent years saw a great effort in minimizing their dimensions, weight, and power consumption. The physics behind the fluxgate principle is rather complex and makes simulations difficult and only partially used in the literature. The limited physical access to micro sensors for measurements and the need to optimize the entire integrated system, including the sensor geometry and the excitation and readout circuits, make numerical analyses particularly useful in the design of miniaturized sensors. After a thorough review of the miniaturized solutions proposed so far, the present paper examines in detail the possibility of adopting a model based approach for designing miniaturized fluxgate sensors. The model of the fluxgate effect of two different technologies proposed in the literature has been implemented to benchmark simulation results with real data. In addition to the advantages for an optimized design, the implementation and computational challenges of the numerical analyses are precisely outlined.

Twist extrusion is a processing method involving the extrusion of a sample with a prismatic cross-section using a tool composed of four prismatic parts bisected by a screw component. A beneficial change in mechanical durability is one of the main factors enabling the use of highly durable Al-Mg-Mn-Sc-Zr alloys to construct functional components of non-stationary robots. As part of the present research, ANSYS® software was used to simulate a twist extrusion process. An analysis of a sample entering and passing through the entire twisting area was performed, up to the point of full twisting of the base of the sample. The stress conditions in the sample were analysed as it passed through the twisting area. The highest stress values (reaching up to 600 MPa) were detected at the tips of the sample face as the sample exited the twisting area. The lowest stress values, at around 170 MPa, were detected at the side edges of the sample.

Uygulama sahalarındaki sınırlar sebebi ile yapıların şevler üzerine ve/veya içine inşa edilmesi durumunda yapıların davranışı şevlerin varlığından etkilenmekte olup bu durum etkileşimli davranış analizlerini gerektirmektedir. Yapı-şev sisteminin bütünsel stabilitesini etkileyen parametreler şevin yüksekliği ve eğimi, yapının şeve uzaklığı, temel zemini türü ve yapının geometrik durumudur. Bunların yanı sıra, dolguların yumuşak zeminler üzerine inşa edilmesi taşıma kapasitesi göçmesi ve şev stabilitesi gibi geoteknik problemleri de barındıran bir zemin-yapı etkileşimi problemi oluşturmaktadır. Bu çalışmanın amacı bütünsel davranış üzerinde farklılık oluşturan tüm parametrelerin davranış üzerindeki etki derecesinin belirlenmesidir. Bu amaçla, dolgu-şev ve temel zemininden oluşan etkileşimli sistemin davranışı birçok parametrik değerlendirme yapılarak iki boyutlu uzayda sonlu elemanlar analizleri yapılarak irdelenmiştir.

The objective of this paper is to numerically study the behavior pipe pile under axial compression embedded in organic soil has been numerically predicted. The pipe pile used in the study has been produced by steel and it has outer and inner diameters of 20 mm and 15 mm, respectively. The pile embedded in organic soil, which has the pile length ratios of 10, 20 and 30 (L/D), has been exposed to the axial load for different diameter ratios (d/D = 0, 0.25, 0.50 and 0.75). Numerical analyses have been performed by using Plaxis 3D computer program which is based on finite element method. The capability of the numerical analysis in the prediction of the load capacity of pipe pile has been studied. It has been understood that the results obtained from numerical analysis and experiment are in a good agreement, and then it has been observed in the parametric study that the load capacity of single pipe pile increases with the increase of the pile length and the wall thickness. [ABSTRACT FROM AUTHOR]

The paper presents the results of 5 case studies on complex site effects selected within the project for the level 3 seismic microzonation of several municipalities of Central Italy damaged by the 2016 seismic sequence. The case studies are characterized by different geological and morphological configurations: Monte San Martino is located along a hill slope, Montedinove and Arquata del Tronto villages are located at ridge top whereas Capitignano and Norcia lie in correspondence of sediment-filled valleys. Peculiarities of the sites are constituted by the presence of weathered/jointed rock mass, fault zone, shear wave velocity inversion, complex surface and buried morphologies. These factors make the definition of the subsoil model and the evaluation of the local response particularly complex and difficult to ascertain. For each site, after the discussion of the subsoil model, the results of site response numerical analyses are presented in terms of amplification factors and acceleration response spectra in selected points. The physical phenomena governing the site response have also been investigated at each site by comparing 1D and 2D numerical analyses. Implications are deduced for seismic microzonation studies in similar geological and morphological conditions. [ABSTRACT FROM AUTHOR]

Soil nailing as a construction practice has turned into a prime earth retention and slope stabilization technique. Present study undertakes potential parametric optimization in soil nailing by considering soil nail interaction and back analysis of the pull-out strength of nail using Finite Element Analysis using PLAXIS 2D. Results suggested pull-out strength as a function of depth, thereby providing a potential scope for optimization of soil nail length pattern. The observed trend of results has been further validated using Limit Equilibrium Analysis. Further, dynamic analysis was undertaken to ensure the seismic stability considering the reduced nail length pattern using FHWA guidelines and the numerical approaches like finite element and limit equilibrium methods. Results suggest that the observed trend with reduced nail length patterns caused mild increment in the serviceability conditions like horizontal deformation, but the results were observed to be within permissible limits in the ultimate limit state. Furtherance to the numerical analyses, a numerical regression analysis was undertaken to develop a correlation between the geotechnical parameters, nail length patterns and the limit conditions. [ABSTRACT FROM AUTHOR]

Hybrid design of 18‐story "Tall Wood Building" in Vancouver and alternative in wood The first part of this paper discusses the design of one of the world's tallest hybrid wood buildings: the "Tall Wood Building", a 18‐story, 53 m tall student residence on the campus of the University of British Columbia in Vancouver, Canada. The building consists of 17 floors in solid wood construction on one floor in reinforced concrete. Two vertical concrete cores provide the required lateral load resisting system. The timber construction system consists of cross laminated timber, point supported on glulam beams. While the construction of the concrete cores lasted 14 weeks, the entire solid wood structure took only ten weeks to complete. Substantial shortening of the project duration and reduction of the ecological footprint of the building could have been achieved, if wood had been used for the cores. In the second part of this work, we examine the possibility of designing the building with solid wood cores. The results of a validated numerical model show that the criteria for earthquake and wind design of the current Canadian building standards can be met. [ABSTRACT FROM AUTHOR]

Penetration is the most critical concept in ballistic studies. Penetration is defined as the ability to penetrate the target. Bullet tip geometry and velocity are the most important factors in terms of the penetration. There are many limitations in increasing the velocity of the bullet. Therefore, projectile geometry can be studied in this field. So, in this study, six different tip geometry of bullet are investigated in terms of the ballistic impact performance. Numerical simulations are performed in ANSYS program, which is the finite element program. Explicit dynamics toolbox is used to perform the numerical study. Six different tip geometry of bullet was modeled in 3D modeling program. The geometries are transferred to the ANSYS workbench program. Initial velocity is accepted as 300 m/s for all conditions. Within this study, the impact energy performance of six different bullet tip geometry was obtained. In addition, stress and deformation results on the target were also compared. [ABSTRACT FROM AUTHOR]

Waves, a constant presence in the ocean, significantly influence the stability of a vehicle's water entry. In the present work, the effects of waves on the water entry of a vehicle equipped with a cavitator, utilizing the Computational Fluid Dynamics (CFD) method. The Stokes V wave theory serves as the basis for wave simulations, while the moving computational domain method is used to realize the motion of the vehicle. The water entry process is most influenced by waves at the peak point of wave inclination. This research delves into the impacts and underlying mechanisms of wave height, entry angle, and speed on the water-entry process, particularly focusing on the range of wave influence. Re-entry may occur when the entry angle is smaller than the maximum wave inclination. Under such circumstances, the vehicle's motion could become more erratic, potentially leading to re-entry failure. Consequently, two critical angles are defined: one where re-entry is likely to occur, and another where re-entry is inevitable. The influences of wave parameters and entry angle on the possibility of re-entry are investigated. The proposed critical angles and their calculation method lay the groundwork for future research aimed at ensuring safe water entry for vehicles amid waves. • The fluid-structure coupling between waves and vehicles is realized using moving computational domain method. • Two critical angles are defined as the water-entry angles where re-entry is likely to occur and bound to occur. • A theoretical method for calculating the probability of re-entry is established. • The law of influence of the entry and wave parameters on the range of wave influence on the water entry is obtained. [ABSTRACT FROM AUTHOR]

• This paper analyses a new retrofitting method based on the use of a titanium threaded rod. • The good compatibility with historic masonry makes titanium suitable for seismic-upgrading applications. • Titanium rods were used to reinforce the masonry walls against in-plane actions. • Reinforced structures presented enhanced behavior and increased mechanical properties. Shear walls in historic constructions often require retrofit. The lateral load capacity is frequently insufficient to withstand seismic actions. Threaded titanium rods embedded in mortar bed joints have emerged as a viable solution to reinforce brickwork shear walls. The use of a high tensile strength and ductile material (titanium alloys), with a high degree of reversibility of the retrofit intervention, is promising as it represents a new opportunity in masonry conservation. Aiming at studying the effectiveness of the titanium rod repair, this research had a twofold goal: 1. laboratory tests were performed to investigate the structural response of reinforced walls at macro-scale level; 2. a numerical modelling strategy was implemented to fill the knowledge gap regarding the material properties of brickwork masonry (English and Flemish bond). Quasi-static cycling loading tests performed on full scale (1200x1200 mm, two wythes thickness) specimens demonstrated how bed joint reinforcement using threaded titanium rods produced a significant increase in the lateral load and deformation capacities. To provide an effective tool for predicting all material parameters, as input data, and for designing the proposed strengthening system, a step-by-step procedure - based on the use of digital image processing (DIP) techniques, homogenization theories and micro-modelling strategies - was therefore proposed. [ABSTRACT FROM AUTHOR]

A/B testing is used in digital contexts both to offer a more personalized service and to optimize the e-commerce purchasing process. A personalized service provides customers with the fastest possible access to the contents that they are most likely to use. An optimized e-commerce purchasing process reduces customer effort during online purchasing and assures that the largest possible number of customers place their order. The most widespread A/B testing method is to implement the equivalent of RCT (randomized controlled trials). Recently, however, some companies and solutions have addressed this experimentation process as a multi-armed bandit (MAB). This is known in the A/B testing market as dynamic traffic distribution. A complementary technique used to optimize the performance of A/B testing is to improve the experiment stopping criterion. In this paper, we propose an adaptation of A/B testing to account for possibilistic reward (PR) methods, together with the definition of a new stopping criterion also based on PR methods to be used for both classical A/B testing and A/B testing based on MAB algorithms. A comparative numerical analysis based on the simulation of real scenarios is used to analyze the performance of the proposed adaptations in both Bernoulli and non-Bernoulli environments. In this analysis, we show that the possibilistic reward method PR3 produced the lowest mean cumulative regret in non-Bernoulli environments, which proved to have a high confidence level and be highly stable as demonstrated by low standard deviation measures. PR3 behaves exactly the same as Thompson sampling in Bernoulli environments. The conclusion is that PR3 can be used efficiently in both environments in combination with the value remaining stopping criterion in Bernoulli environments and the PR3 bounds stopping criterion for non-Bernoulli environments.

Rebars corrosion phenomena can modify the structural behaviour of reinforced concrete (RC) members and consequently the seismic performance of RC structures. Since many existing RC structures are affected by this phenomenon, the influence of the reinforcement corrosion on the seismic performance is still under examination, especially when the corrosive attack is localized in the dissipative areas of the plastic hinges. In this work, the effect of localized corrosion is numerically investigated, through the adoption of a suitable finite element model, object of validation with the outcomes of an experimental campaign carried out in the Laboratory of the University of Rome “Tor Vergata”, on un-corroded and corroded RC columns subjected to axial load and cyclic horizontal actions. Particular attention has been paid to the definition of the three-dimensional model and to the modelling of the corroded rebars and their corrosion morphology. Indeed, different modelling strategies are proposed with the aim to properly simulate the cyclic behaviour of the corroded columns. The main results show how more refined strategies taking into account the morphological aspects of the corrosion phenomenon produce a better fit with the experimental results for both Damage Control and Life Safety limit states performance.

The need of repairing and retrofitting masonry buildings, typical of Italian and European built heritage, determined a growing interest towards the development of effective and cost efficient innovative strengthening solutions. Among the different techniques currently available, the adoption of composite materials, such as Fiber Reinforced Polymers (FRPs), proved to be one of the most viable solutions for the strengthening of masonry structures. If not properly fixed, a common failure mode of this system is the early debonding of the reinforcement from the substrate. For this reason, several experimental tests and numerical analyses are currently available in the literature, clarifying and predicting the bond behavior of FRP glued to masonry substrates. The purpose of this paper is to provide an overview of the results obtained by the different experimental works, of the numerical analyses performed both for evaluating and validating experimental results and of the simplified analytical models currently available for the prediction of the maximum capacity of the strengthening systems. Results of extended experimental campaigns, carried out also within different Round Robin Test (RRT) series, with several laboratories involved, and recent model calibrations will be discussed together with the approach proposed by the actual guidelines.

Although it is well known that dry open rocky grassland vegetation on shallow serpentine (ultramafic) soils represents one of the most interesting, highly endemic, and often studied vegetation types, the authors of several detailed studies of Balkan serpentine flora and vegetation suggested that the vegetation cover of Balkan ultramafics needs further exploration due to its heterogeneity. In this article, phytosociological characteristics of seven poorly known associations of grassland communities from the order Halacsyetalia sendtneri are analysed. In order to provide additional descriptions of these communities (with diagnosis and lists of diagnostic, dominant, and constant species), check their phytosociological validity, and confirm their syntaxonomical position, the stands of these communities were compared with 18 associations distributed throughout the area of serpentine outcrops in Bosnia and Herzegovina and Serbia. The results of cluster analysis confirmed that the analysed heretofore poorly known associations in the vegetation of open rocky serpentine grasslands are floristically well-defined.

Although there is a type of carrier system that is not frequently preferred today, there is a considerable amount of masonry structure built in the past in our country. It is important to design the masonry structure systems which show limited strength and ductility in comparison with reinforced concrete or steel structures under horizontal loads, especially in severe earthquake regions where there is a demand for extra - elastic demand.In this study, a fast, easy and realistic calculation algorithm for the stress-based analysis of existing and new masonry structures,electronic tables are developed and the analytical results of the prepared program are compared with the results of the end - effector method and stress - based package program for sample structure models.

Until now, some test specimens with different shapes and loading mechanisms have been utilized for investigating the cracking behavior of adhesive bounded joints. In this research, using a novel test configuration called adhesive short bend beam specimen containing an inclined crack and loaded by three-point bending, mixed mode I/II fracture parameters of a crack initiated in the adhesive part is studied. Compared to other test methods, the specimen used in this research needs a lesser amount of material and the fracture test can be performed easily. A large number of finite element models of this specimen were analyzed using ABAQUS code to study the effect of adhesive and adherent type, and also the crack length and loading span distance on KI, KII, T-stress and fracture initiation direction under different mode mixities. The results showed that the fracture parameters (and in particular the shear mode component) are sensitive to the type and location of adherent in the bounded joint; however, the shape and size of fracture plastic zone is not affected noticeably by the type of adhesive-adherent materials. It was also shown that the complete mode mixities ranging from pure mode I to pure mode II can be introduced for adhesive bounded joints using the proposed test specimen and therefore the specimen is a good candidate test configuration for investigating the mixed mode I/II fracture behavior of adhesive bounded joints.

Reliability of liquid rocket engines is strictly connected with the successful operation of cooling jackets, able to sustain the impressive operative conditions in terms of huge thermal and mechanical loads, generated in thrust chambers. Cryogenic fuels, like methane or hydrogen, are often used as coolants and they may behave as transcritical fluids flowing in the jackets: after injection in a liquid state, a phase pseudo-change occurs along the chamber because of the heat released by combustion gases and coolants exiting as a vapour. Thus, in the development of such subsystems, important issues are focused on numerical methodologies adopted to simulate the fluid thermal behaviour inside the jackets, design procedures as well as manufacturing and technological process topics. The present paper includes the numerical thermal analyses regarding the cooling jacket belonging to the liquid oxygen/liquid methane demonstrator, realized in the framework of the HYPROB (HYdrocarbon PROpulsion test Bench) program. Numerical results considering the nominal operating conditions of cooling jackets in the methane-fuelled mode and the water-fed one are included in the case of the application of electrodeposition process for manufacturing. A comparison with a similar cooling jacket, realized through the conventional brazing process, is addressed to underline the benefits of the application of electrodeposition technology.

Several historical towns and sites in Italy and other parts of Southern Europe were built on topographic reliefs, and they host inestimable cultural heritage. In Calabria (southern Italy), the historical town of Gerace is located in a highly seismic area and lies on top of an unstable cliff, constituted by a soft rock slab overlying a thick clay shale formation. A comprehensive study was carried out to reproduce the seismic response of the cliff and analyse potential effects due to severe earthquakes, such as those attributed by historical documents to the Calabrian seismic sequence that occurred in 1783. Much effort was spent on the geotechnical characterisation of the soils; in particular, a subsoil model was obtained by combining data from field and laboratory tests. The seismic response of the cliff due to the first event of the Calabrian sequence was simulated by 1D and 2D non-linear analyses, which enabled an assessment of the influence of topography on the seismic response. The 2D analyses justified the occurrence of large permanent deformations, as reported by the chronicles following the historical seismic sequence. [ABSTRACT FROM AUTHOR]

The impact performance of the material is critical property in the weapon industry. In particular, pressure distribution concept in barrel has revealed the need to work on this issue. Therefore, the behavior of the barrel was investigated, when the explosion pressure was realized in the barrel. In this study, different pressure values were applied to the inside of the barrel to obtain critical stress region. The barrel of the new generation long range sniper weapon of the American Barret company, which is legendary with the M82A series, was used. 3D barrel model was created in SOLIDWORKS program. ANSYS workbench static structural toolbox was used to perform the proposed study. Within this study, the critical points in sniper weapon barrel were determined in terms of the stress and deformation concepts. [ABSTRACT FROM AUTHOR]

In the current paper, using experimental studies and numerical analyses, the combined effect of facing inclination and uniform surcharge on the behaviour of geosynthetic-reinforced soil (GRS) walls under working stress conditions is evaluated. Data from four well-instrumented GRS walls at the end of construction and under surcharge applications were used considering different facing types, inclinations, and toe conditions. The numerical analyses were carried out considering different wall heights, facing inclinations, and surcharges. Moreover, data from the physical and numerical model studies were utilised to verify the predictability of the AASHTO simplified (2017) and Ehrlich and Mirmoradi (2016) design methods and some limitations of each method are discussed. The results clearly indicate that for better representation of the actual conditions, the uniform surcharge and facing inclination should not be independently taken into account in the design procedures. [ABSTRACT FROM AUTHOR]

Test setups and loading histories aim to replicate the real conditions of the building structures. However, most of the tests on beams found in literature do not include gravity loads in the cyclic loading history. An experimental campaign was carried out. Two beam specimens, named CB0 and CB1, designed to exhibit different failure modes were subjected to a loading protocol that involved the imposition of reversed cyclic loading and simultaneous gravity load. The aim was to validate the test procedure for different beam failure modes. Consequently, specimen CB1 failed by rupture of the tensile reinforcing bars while specimen CB0 failed due to concrete crushing and buckling of the compressed reinforcing bars. Results show that the presented loading protocol does not control the failure mode of the specimens. The specimens were also simulated numerically, and the results were comparable with the experimental observations in terms of load capacities, crack patterns, and failure modes. [ABSTRACT FROM AUTHOR]

Occurrence of gas-extraction-induced earthquakes in the Groningen Province of the Netherlands raised the need for dynamic performance assessments of the regional flood defence system, consisting of an extended levee network. The soils underlying parts of the levees comprise Holocene tidal deposits, susceptible to liquefaction and cyclic strain softening. This paper describes the numerical methodology adopted to evaluate the seismic performance of such important flood protection structures, including: (1) the development of ground motions consistent with regional seismic hazard, (2) two dimensional, effective-stress, dynamic numerical simulations of levees, (3) use of calibrated advanced constitutive models to simulate complex soil behavior, (4) estimation of post-seismic deformations, and (5) validation against centrifuge experiments. The application of this methodology captured the important mechanisms governing these types of problems, resulted in an improved characterization of system behavior and allowed for a more rational and reliable prediction of levee performance. [ABSTRACT FROM AUTHOR]

Herein, 15 fungi species belonging to different genera of Pezizales were studied morphologically and molecularly. During the morphological analyses performed by means of Primer 7 software, 28 characters were used, mainly including the stalk, cap, asci, and spores, to assess the taxonomical relationships of the fungi species. The data matrix and nMDS plot approaches based on the morphological data were highly functional in the determination of the taxonomical relationship of very closely related fungi taxa, particularly at the genus level. Moreover, the data from the ISSR locus analyses significantly supported the current morphological relationships on a wide scale. Contrary to the morphological data expressing taxonomical relationships related to morels or early morels, a minor exceptional condition was determined inferring to the relatively higher genetic similarity among Verpa and Gyromitra in the dendrogram connected with the ISSR analyses. [ABSTRACT FROM AUTHOR]

Arch structures made of double corrugated steel sheets, known as K-span, are used as self-supporting building roofs. The cold-rolling method of arch panel production causes the creation of deep-press formed transverse corrugation. The unusual profile shape significantly impedes the use of known design methods. In extreme cases, this might lead to the failure and collapse of K-span structures. This paper presents a method for testing full-size K-span structures using various measuring techniques, and provides a method of numerical analysis of the double corrugated structures. The results of the tests were compared with the results of the numerical analysis to assess the validity of the assumptions made for the calculations. A comparison of the test results and the numerical analyses helped to give practical guidelines for evaluation of the load capacity and stability of double corrugated K-span structures. • Test bench and measuring systems for testing of double corrugated arch structures. • Analysis of displacements of entire arch structures with substitute surface load. • Comparative computational analyses and construction rules of the FEM numerical model. • Research and computational difficulties and their influence on analysis results. [ABSTRACT FROM AUTHOR]

• Embedded barriers may reduce substantially tunnelling-induced ground settlements. • The roughness of the barrier-soil interface affects the barrier efficiency significantly. • A barrier should extend one tunnel cover beyond the section to be protected. • 2D modelling of a line of piles provides misleading results; 3D modelling is needed. • Barrier efficiency is reduced by 10–40% depending on weight of adjacent buildings. Ground displacements caused by underground excavations in densely urbanised areas often requires the adoption of protective techniques to prevent damage to existing buildings. When the tunnel passes to the side of a potentially affected building, tunnelling-induced settlements can be reduced pre-installing a protective barrier between the tunnel and the building. Usually, this mitigation technique is implemented in practice based on empirical knowledge rather than as a result of a rational design process. This paper presents a numerical study to evaluate the efficiency of different schemes of embedded barriers, using numerical analyses as a tool to understand the main mechanisms of soil-barrier interaction. Two- and three-dimensional FE analyses were carried out assuming a continuous embedded diaphragm wall or a discontinuous piled wall. The barrier was assumed of either infinite or finite horizontal extension, to evaluate the minimum extension needed to obtain in a given section a settlement reduction similar to that attained under plane strain conditions. The effects induced by wall installation and those associated to the presence of a pre-existing building were also accounted for. The results of the analyses permitted to recognise the main factors affecting the efficiency of a protective barrier, providing some guidance for a rational design of the intervention. [ABSTRACT FROM AUTHOR]

Abstract The aim of this work is to design the arms of a specific excavator adopting unconventional materials and comparing the machine performance due to components lightweight. A real excavator is numerically studied under specific load conditions; subsequently a series of experimental tests were performed in order to quantify the dynamic effects induced by moving load. On the basis of the actions determined by the load diagram and the inertia ones, a structural evaluation was performed on the arms in their original configuration. The results obtained were assumed like minimum performance for new design components using aluminum alloy and composite material with carbon fibers instead of structural steel. The geometry developed by adopting the composite material has an elliptical section instead of a classical rectangular section. With the adoption of the new solutions there is a total weight reduction up to 64.1% for the solution made of composite materials. [ABSTRACT FROM AUTHOR]

Abstract A number of classic problems in the stability of thin walled structures in the elastic-plastic range which have been examined to some extent by the present author over the years are collected and discussed in order to highlight the advantages and drawbacks of analytical and numerical approaches. Issues related to the modes interaction, to the material modelling and to the imperfection sensitivity are examined with respect to well-known conundrums in the theory of stability and it is shown that the combination of all these aspects is such that any numerical analysis, despite the availability of modern very powerful nonlinear FE packages, must be preceded by a careful examination of the particularities of the problem at hand. In fact, a capable insight into the mechanics of the problem is shown to remain paramount in order to attain a good agreement with experimental results and provide reliable predictions for a large number of engineering tasks. Highlights • Some classic problems in the elastic-plastic stability of thin walled structures are presented. • The discrepancy between flow and deformation theory is examined. • The possible drawbacks of numerical analyses are pointed out. [ABSTRACT FROM AUTHOR]

Highlights • Class A FEM predictions of twin tunnel mechanised excavation in Rome are presented. • The main processes occurring during excavation with an EPB shield are modelled. • No assumptions about volume loss and shape of settlement trough are used. • The predictions agree very well with field data from similar cases. Abstract Contract T3 of Line C of Rome underground, currently under construction, crosses the archaeological area of the historical centre, with significant interferences with the existing monumental built environment. A fully instrumented green field control section was established at the beginning of this contract, in representative ground conditions. This paper presents a thorough Class A prediction of the passage of the tunnels through the control section, obtained using a recently developed advanced numerical procedure. The ground was modelled with a non-linear constitutive law, calibrated with all the available data from the geotechnical investigation. The main physical processes occurring around the shield, including cutter-head overcut, shield tapering and tail void grouting were modelled in detail. The numerical results agree qualitatively with the findings from well documented case histories and results from physical models. The installed instrumentation will provide an opportunity to test the ability of the adopted procedure to reproduce quantitatively the measured performance, once the tunnels will cross the control sections and the field data will become available. [ABSTRACT FROM AUTHOR]

Abstract The study aims to describe the geological and geostructural layouts of an unstable sea arch located in a very attractive tourist area of Southern Italy. On the basis of ad hoc field surveys and laboratory tests, the problems of an in-depth geo-mechanical characterization of the rock mass are discussed in details and its main strength parameters are derived. An indirect assessment of the possible geostatic stress field due to the neotectonic events, which affected this sector of Apennine Range during the last 100,000 years, is proposed and validated by means of numerical non-linear FE analyses. The results suggest that the presence of a lateral thrust acting into the promontory located at the back of the arch, is very likely and its effects would agree well with the failures occurred in the past on the arch surfaces. It is concluded that any possible intervention should be carefully designed on the basis of the highlighted factors and further investigations. Highlights • Geological and geostructural descriptions of an unstable sea arch are performed • In-depth geo-mechanical characterization of the rock mass on the basis of field surveys and laboratory tests is carried out • An assessment of the geostatic stress field due to the neotectonic events is obtained by means of back engineering through FE • The results are validated with respect to the observed failures [ABSTRACT FROM AUTHOR]

This paper proposes an improved model for the reinforced concrete shear walls. The main contribution of this work is to provide a comparison between the proposed numerical model and an existed experimental test. It indicates the necessity of performing more complex numerical simulations, in order to describe the behaviour of L-shaped walls. To validate the accuracy of the proposed model, an investigation has been carried out in two parts. In the first part, the numerical model is developed by ANSYS to predict the cyclic behaviour of the L-shaped reinforced concrete walls, which has been designed according to the Algerian seismic design codes. The second part reports a numerical investigation that evaluates the behaviour of L-shaped walls by comparing the proposed model with the experimental tests. The results of this study demonstrate that the deformation by inflection at the base of the L-shaped reinforced concrete shear walls is dominant and occupies nearly eighty percent of the total deflection. The established model constitutes a practical tool for developing and reviewing the conditions of the reinforcement stipulated in the design codes. [ABSTRACT FROM AUTHOR]

Due to the inherent complexity of biological applications that more often than not include fluids and structures interacting together, the development of computational fluid–structure interaction models is necessary to achieve a quantitative understanding of their structure and function in both health and disease. The functions of biological structures usually include their interactions with the surrounding fluids. Hence, we contend that the use of fluid–structure interaction models in computational studies of biological systems is practical, if not necessary. The ultimate goal is to develop computational models to predict human biological processes. These models are meant to guide us through the multitude of possible diseases affecting our organs and lead to more effective methods for disease diagnosis, risk stratification, and therapy. This review paper summarizes computational models that use smoothed-particle hydrodynamics to simulate the fluid–structure interactions in complex biological systems.