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Food security has become a significant issue due to the growing human population. In this case, a significant role is played by agriculture. The essential foods are obtained mainly from plants. Plant diseases can, however, decrease both food production and its quality. Therefore, it is substantial to comprehend the dynamics of plant diseases as they can provide insightful information about the dispersal of plant diseases. In order to investigate the dynamics of plant disease and analyze the effects of strategies of disease control, a mathematical model can be applied. We show that this model provides the non-negative solutions that population dynamics requires. The model was investigated by using the Atangana-Baleanu in Caputo sense (ABC) operator which is symmetrical to the Caputo-Fabrizio (CF) operator with a different function. Whereas the ABC operator uses the generalized Mittag-Leffler function while the CF operator employs the exponential kernel. For the proposed model, we have displayed the local and global stability of a nonendemic and an endemic equilibrium, existence and uniqueness theorems. By applying the fractional Adams-Bashforth-Moulton method, we have implemented numerical solutions to illustrate the theoretical analysis.

In many applications, free surface flow through rigid porous media has to be modeled. Examples refer to coastal engineering applications as well as geotechnical or biomedical applications. Albeit the frequent applications, slight inconsistencies in the formulation of the governing equations can be found in the literature. The main goal of this paper is to identify these differences and provide a quantitative assessment of different approaches. Following a review of the different formulations, simulation results obtained from three alternative formulations are compared with experimental and numerical data. Results obtained by 2D and 3D test cases indicate that the predictive differences returned by the different formulations remain small for most applications, in particular for small porous Reynolds number ReP < 5000. Thus it seems justified to select a simplified formulation that supports an efficient algorithm and coding structure in a computational fluid dynamics environment. An estimated accuracy depending on the porous Reynolds number or the mean grain diameter is given for the simplified formulation.

We present a new 2.5D model for predicting the concentration of nitrogen dioxide (NO2) at street level in an urban area. This work develops the first prototype of a tool that should provide fast quantitative answers to help decision-making on the suitability of implementing traffic restrictions during air pollution episodes. The model first solves the wind flow over the city streets ignoring vorticity and turbulence. The obtained velocity field is used to transport the pollutant via a semi-Lagrangian model, combining the particle finite element method of second generation (PFEM2) with the finite element method. A variable absorption term is used to account for the part of the contaminant entering and leaving the calculation plane. The NO2 emissions are estimated from the historical traffic data. The model has been tested during four air pollution episodes in the city of Barcelona (Spain), two in summer and two in winter. A comparison against experimental measurements has been performed at seven different locations throughout the city with promising results.

Granular flow is common in many industrial applications, and involves heat generation from frictional contacts and inelastic collisions between particles. The self-heating process is still poorly understood despite being intrinsic to many processes. This work, for the first time, explores this problem experimentally by quantifying the temperature rise of granular flows in a rotating drum with a robust methodology based on infrared thermography. Particles of four different materials (lead, steel, plastic and glass) are used in the experiments, at various rotation speeds and drum fill ratios. To assess the mechanical behaviour, the flow regime of every experiment was determined. It was inferred that particles with higher density tend to generate more heat. It was also revealed that increasing the rotation speed favours the temperature rise. At the same time, the fill ratio had the least influence on the thermal response of the particulate systems considered. his project is funded through Marie SKŁODOWSKA-CURIE Innovative Training Network MATHEGRAM, the People Programme (Marie SKŁODOWSKA-CURIE Actions) of the European Union's Horizon 2020 Programme H2020 under REA grant agreement No. 813202. Dr. Franci acknowledges the support from MCIN/AEI/10.13039/501100011033 and FEDER Una manera de hacer Europa for funding his work via project PID2021-122676NB-I00. Prof. Oñate acknowledges the Severo Ochoa Programme through the Grant CEX2018-000797-S funded by MCIN/AEI/10.13039/501100011033.

We present a general framework for the analysis and modelling of frictional contact involving composite materials. The study has focused on composite materials formed by a matrix of rubber and synthetic or metallic fibres, which is the case of standard tires. We detail the numerical treatment of incompressibility at large deformations that rubber can experience, as well as the stiffening effect that properly oriented fibres will induce within the rubber. To solve the frictional contact between solids, a Dual Augmented Lagrangian Multiplier Method is used together with the Mortar method. This ensures a variationally consistent estimation of the contact forces. A modified Serial-Parallel Rule of Mixtures is employed to model the behaviour of composite materials. This is a simple and novel methodology that allows the blending of constitutive behaviours as diverse as rubber (very low stiffness and incompressible behaviour) and steel (high stiffness and compressible behaviour) taking into account the orientation of the fibres within the material. The locking due to the incompressibility constraint in the rubber material has been overcome by using Total Lagrangian mixed displacement-pressure elements. A collection of numerical examples is provided to show the accuracy and consistency of the methodology presented when solving frictional contact, incompressibility and composite materials under finite strains.

The suffusion susceptibility of the soil samples is evaluated through an erosion resistance index. Thanks to existing statistical analyses, the erosion resistance index is estimated from several soil parameters. In actual exploitation, the soil properties with the input parameters related to the grain distribution of the soil… vary greatly from the original design value due to the influence of many factors. One of the factors is the inherent variability. Inherent soil variability is modelled as a random field. The usual problems used to assess the suffusion susceptibility may be not give accurate results or fully evaluate the actual working ability of the ground in each case. This is one of the reasons why dams are still eroded when they are put into use. The paper aims predict erosion resistance index of the earth dam using two-dimensional (2D) Stochastics random field, modelling the initial problem, considering the variability spatial of soil properties, using the assumption of a Normal random field of soil characteristics parameters. The paper shows the predicted results of the variability spatial of erosion resistance index of Phu Vinh dam-Vietnam. Furthermore, the paper also represents the happened probability of suffusion susceptibility at the different zones in the earth dam body.

In this paper an enhanced version of the semi-explicit Particle Finite Element Method for incompressible flow problems is presented. This goal is achieved by improving the solution of the advective sub-problem that results of applying the Strang operator splitting to the Navier–Stokes equations. An acceleration term is taken into account in the solution of the advective step and the Stokes problem. The solution of the advetive step is perfomed using a SPH kernel. Two test cases are solved for validating the methodology and estimating its accuracy. The numerical results demonstrate that the proposed scheme improves the accuracy of the semi-explicit PFEM scheme.

The methodology previously proposed by the authors to solve particle-laden turbulent flows through a multiscale approach is extended by introducing a continuous function for thedispersed phaseconcentration. The proposed continuous model is especially useful for studying the motion of particle streams in which gravitational and inertial effects cause the particles to deviate from a simple trajectory following the surrounding flow, as would be the case for the limit of very small, massless particles. The results show an excellent comparison between the solutions obtained using the continuous model and simulations evaluating the forces on each particle individually. Distinct advantages of the continuous approach are a much lower computational overhead, a better load balance and ease ofparallelization. The multiscale methodology proposed may be used in the area ofmodeling and simulationof airborne infectious diseases.

This study investigates a retailer's ordering strategy under the framework of the economic order quantity (EOQ) model. A supplier offers a retailer a disposable coupon and allows it to place a special order at any time in a promotion period. The promotion period is not necessary short and shortages are allowed throughout the time horizon. In addition to the special order time and the special order quantity, the retailer needs to decide whether to place some regular orders in the promotion period before placing the special order for the purpose of making better use of this coupon. We show that the coupon should be used to the retailer's first order in the promotion period regardless of the duration of the promotion period. Moreover, the retailer's maximum inventory level is higher than that in the classical EOQ model. We find that a longer promotion period can benefit the retailer by endowing it with more flexibility in its decision-making. Therefore, the supplier can improve the cash flow and reduce the overstock by integrating a disposable coupon with a longer promotion period. Numerous managerial insights are obtained from sensitivity analysis and numerical experiments.

At present, the beam-column connection system through a self-centering post-tensioned connection is currently an alternative to improve the seismic behavior in reinforced concrete buildings; by allowing its elements to have a linear behavior (no damage) in the face of displacements produced by seismic actions. This paper deals with the numerical modeling of the seismic behavior for a self-centering connection based on the Discrete Element Method (MED) is presented, with the aim of validating the hysterical response of the numerical model with an experimental test of the literature. The results demonstrated the horizontal distortions in the column, which are the product of the numerical simulation of the model subjected to a load that increases over time with 4 different stiffness coefficients. In addition, the hysteretic graph is presented as a result of the numerical simulation of the model, with an adequate stiffness coefficient and normal damping, subject to a cyclic load that is reversed as a function of time. The movement of the connection is controlled by the horizontal distortions of the column, achieving an approximate reproduction of the hysterical behavior expected in this type of connection. With the results shown, a simple bilinear hysteresis law is proposed, which allows its simplified use for its application in the modeling of reinforced concrete buildings with self-centering connections.

To obtain an optimum power market the deregulation process is implemented for the entire electrical market and further classified as transmission and distribution units. Each firm focuses on delivering its best output which leads to congestion issues on transmission lines as there is in-adequate transmission capability to satisfy the load demand, and transmission congestion occurs. Transmission cable congestion results from a lack of coordination between the utilities that handle generating, transmission, and distribution leading to a generator failure, an abrupt increase in load demand, or the miscarriage of equipment, all of which can be fixed by FACTS devices. In this work, transmission line congestion is reduced using FACTS devices like UPFC and IPFC. The primary goal is to determine where FACTS devices should be placed. The main goal is to use the ANTLION optimization algorithm to locate the optimal position and size for FACTS devices. In an IEEE-14 bus system, UPFC and IPFC are individually connected and parameters are analyzed and formulated for better transmission among energy sectors.

'''– Design of steep slopes and retaining walls, reinforced with geotextile or geogrids, requires internal stability checks usually referred to a critical failure surface, which determines the amount of reinforcement required. In determining the length of the reinforcement layers the position of the critical surface and also of the sub-critical surfaces must be considered. In relation to these, are verified the anchorage lengths required to ensure the pullout resistance of the reinforcements. This paper presents a study based on limit equilibrium analysis, with bi-linear failure surface, to determine the amount and length of the reinforcement layers required. The model allows replacing Jewell charts by algebraic equations and iterative calculation processes. The results obtained for the minimum length of reinforcements agree with good accuracy for effective friction angles greater than or equal to 30° and indicate that shorter lengths can be used for materials with lower effective friction angle. Expressions for the calculation of the anchorage length are also presented for the three possible cases: anchorage in a section under the projection, part under the projection and beyond the horizontal projection of the slope face. '''Palavras Chave –''' talude, solo reforçado, geotêxtil, geogrelha, superfície sub-crítica, comprimento de reforço. '''Key words''' – slope, reinforced soil, geotextil, sub-critical surface, reinforcement length. *Professor Associado, D.Sc. UTFPR - Universidade Tecnológica Federal do Paraná, Curitiba, Paraná, Brasil. E-mail: [mailto:rfkpuppi@utfpr.edu.br rfkpuppi@utfpr.edu.br] / [mailto:rfkpuppi@gmail.com rfkpuppi@gmail.com] **Professor EBTT, M.Sc. UTFPR - Universidade Tecnológica Federal do Paraná, Curitiba, Paraná, Brasil. E-mail: [mailto:caron@utfpr.edu.br caron@utfpr.edu.br]

In this paper, an analytical solution is developed to investigate soil consolidation around a pile under earthquake loading. The solution is validated using finite element method. The influence of various parameters on excess pore water pressure is analyzed. The results show that excess pore water pressure increases with depth and is positively correlated with n and Neq/N1, while negatively correlated with η, χ, kv, and td. The values of η, χ, kv, Neq/N1, and td affect excess pore water pressure during and after the earthquake, while the value of n only affects excess pore water pressure after the earthquake. The growth rate of excess pore water pressure during the earthquake is positively correlated with n, η, kv, and Neq/N1, and negatively correlated with χ and td. The dissipation rate of excess pore water pressure during the earthquake is positively correlated with η, χ, kv, Neq/N1, and td, and negatively correlated with n. Additionally, a formula for calculating the reconsolidation settlement of pile-soil foundation after an earthquake is proposed, and the effects of pile and soil parameters on pile-soil foundation reconsolidation settlement are analyzed. The results indicate that reconsolidation settlement can be divided into two stages: rapid settlement stage and slow settlement stage. The total settlement of the foundation is positively correlated with n, η, and Neq/N1, while negatively correlated with χ, kv, and td.

The use of steel poles as support structures for lines in Mexico has increased in the last 30 years, mainly due to the increase in urban and suburban sprawl that demand less right of way for this type of infrastructure and less space for their foundations. To fulfill these requirements, numerous studies have been carried out related to dielectric sizing, optimization of the distance between phases to reduce electrical losses, wind hazard associated with the cable-insulator-hardware-structure-foundation system, structural design criteria based on reliability, natural-scale mechanical tests, among others. This article presents some reflections related to the different stages of the design of metal poles for transmission lines, from input data to structural designs, following the criteria of the Mexican electrical industry for a 230 kV pole, 2 circuits, located in Mexicali, B.C.

This article evaluates how the seismic pressures developed in embedded walls are affected by different wall stiffness and various contact soil-wall conditions. Several two-dimensional numerical models of an embedded wall-soil system were developed in Abaqus® by varying the wall stiffness. One model considered the wall as very rigid with a large modulus of elasticity and the other one considered the wall as flexible with original modulus of elasticity. Wall heights of 10, 20 and 30 meters were considered on the models to obtain different wall stiffness. The contact between the soil and the wall is modified by changing the friction coefficient between 0 to 0.75. The response of the soil is validated using 1D nonlinear site response analyses. The analyses are performed using records that match a narrow-band modified target spectrum for a moment magnitude of 7.70. The results show that the rigid walls developed larger seismic pressures than the flexible walls when subjected to the same earthquake records. The seismic soil pressures in the rigid walls do not change considerably by varying the contact condition between the soil and wall. Changes in the friction coefficient have a major impact on the seismic pressure distributions on flexible walls.

The Puerto Rico Soil Engineering Office (OIS) was founded in 1975 and is currently under the Design Area of ​​the Highway and Transportation Authority (ACT). In its foundation, the SEO was composed of a Soils Engineering Division and a Geology Division. Its main function was the subsoil exploration for the geotechnical structures designed and constructed by the PRHTA. Over time, the functions of the SEO evolved while soil engineering and rock engineering were evolving. Today, the SEO continues to attend to inquiries during projects’ design and construction phases. Additionally, the SEO attends several geotechnical initiatives like Geotechnical Asset Management and Unstable Slope Management. This article presents the contributions and innovations in the practice of geotechnical engineering that the OIS has attended and has had a leading role with emphasis on new analyzes and equipment that meet state and federal requirements and current codes that have potential to be implemented in geographic areas in the Caribbean and Latin America with similar geotechnical and geological characteristics.

Nature-based Solutions (NbS) are imperative now, in view of the resulting effects of climate change and man-made alterations in coastal areas. The perspective to address coastal solutions may not be possible to be limited exclusively to ecological solutions. This article, based on a literature review, focuses on hybrid solutions for coastal erosion control. The review highlights examples from around the World that can be applied to islands, having Puerto Rico (PR) as a typical scenario. It presents a summary of how gray infrastructure commonly applied in the past decades can be re-designed and adapted to integrate natural solutions. This article provides significant facts about the merits of structural, ecological, and economical aspects that should be considered on NbS projects. This article helps understand the state of practice and possible solutions that can be implemented, especially, in tropical and sub-tropical regions.

Elbows are components in piping systems whose primary function is to achieve a change in flow direction. Their study is relevant, since they present higher stress levels than those observed in straight sections. Early investigations determined that this effect is caused by the ovalization effect and the presence of external moments. The capacity of a cross section to ovalize when external loads are applied results in increased flexibility of the elbows by decreasing the moment of inertia compared to a straight pipe. In this work, stress levels in elbows caused by external moments and internal pressure are studied. As a case study, a series of elbows of various diameters and thicknesses with suitable characteristics for understanding the phenomenon of ovalization and the comparison of different calculation methodologies is proposed. The stresses obtained by applying the ASME B31.1 and ASME B31.3 codes are compared with those obtained by a numerical model of finite elements, through a novel indicator called the Normative Safety Margin. This indicator considers the admissible stresses established by the specifications for the materials of the accessories. Applying B31.1 Code, higher normative safety margins are obtained than those obtained with B31.3. For the entire series under study and all types of applied loads, lower normative safety margins were obtained when the accessories are more flexible.

The increase in crash-related pedestrian fatalities, primarily in urban streets, has promoted the development of technological innovations to mitigate this global problem. This article presents the results of an experiment that used virtual reality technology to study the performance of pedestrians at mid-block crossings of urban streets and the impact of a Road Information Assistance System [RIAS]. The RIAS was simulated as a handheld device that displays warning symbols or a combination of symbols and real-time information about the vehicles approaching the crosswalk to assist pedestrians in making the crossing decision. The experiment simulated a connected urban environment that can receive and transmit data from sensors in the infrastructure, vehicles, and pedestrians [via the RIAS]. The study evaluated the walking speeds, the vehicle gaps selected to cross the street, and the number of successful crossing events with no collisions. Three groups of twelve subjects [no RIAS, simple RIAS, and complex RIAS] were selected. The age and gender of the subjects, as well as the RIAS type used to cross the street, had significant effects on the average walking speed. The distributions of the average gap accepted by each of the three groups, based on the RIAS type, were statistically different. The group that used the RIAS device displaying symbols only had the worst performance and the highest average gap accepted when crossing the street.

This paper provides experimental data on the temperature rise during granular flows in a small-scale rotating drum due to heat generation. All heat is believed to be generated by conversion of some mechanical energy, through mechanisms such as friction and collisions between particles and between particles and walls. Particles of different material types were used, while multiple rotation speeds were considered, and the drum was filled with different amounts of particles. The temperature of the granular materials inside the rotating drum was monitored using a thermal camera. The temperature increases at specific times of each experiment are presented in form of tables, along with the average and standard deviation of the repetitions of each setup configuration. The data can be used as a reference to set the operating conditions of rotating drums, in addition to calibrating numerical models and validating computer simulations. This project is funded through Marie SKŁODOWSKA-CURIE Innovative Training Network MATHEGRAM1, the People Programme (Marie SKŁODOWSKA-CURIE Actions) of the European Union's Horizon 2020 Programme H2020 under REA grant agreement No. 813202. Dr. Franci acknowledges the support from MCIN/AEI/10.13039/501100011033 and FEDER Una manera de hacer Europa for funding his work via project PID2021-122676NB-I00. Prof. Oñate acknowledges the Severo Ochoa Programme through the Grant CEX2018-000797-S funded by MCIN/AEI/10.13039/501100011033.

At present, the researches on the mechanical properties of sand aggregate mainly focus on the shaping process of particles, and lack the researches on the crushing mechanism. This paper first defines the shaping process of stone powder wall, and explores the crushing mechanism of sand aggregate by adopting multiple times of small energy crushing. The effect of energy is investigated by simulation and experiment. The machine-made sand crushing mechanism is analyzed by establishing corresponding contact mathematical models. The result shows that the stone powder wall involves two mathematical models under impact: the elastic-plastic model at low impact velocity and the elastic-brittle model at high impact velocity. '''Key words:''' machine-made sand; stone powder wall; crushing mechanism; mechanical contact model

The value of the gas-path parameter, exhaust gas temperature margin (EGTM), is the critical index for predicting aeroengine performance degradation. Accurate predictions help to improve engine maintenance, replacement schedules, and flight safety. The outside air temperature (OAT), altitude of the airport, the number of flight cycles, and water washing information were chosen as the sample input variables for the data-driven prognostic model for predicting the take-off EGTM of the on-wing engine. An attention-based deep learning framework was proposed for the aeroengine performance prediction model. Specifically, the multiscale convolutional neural network (CNN) structure is designed to initially learn sequential features from raw input data. Subsequently, the long short-term memory (LSTM) structure is employed to further extract the features processed by the multiscale CNN structure. Furthermore, the proposed attention mechanism is adopted to learn the influence of features and time steps, assigning different weights according to their importance. The actual operation data of the aeroengine are used to conduct experiments, where the experimental results verify the effectiveness of our proposed method in EGTM prediction.

The bearing was a key component of the mining machine tire unloader machine and was subjected to random multiaxial stress during operation. Therefore, the life prediction of bearing was of safety guidance. In this paper, a bearing life prediction method based on the critical plane method under multiaxial random loading was proposed. Firstly, a virtual prototype model was built based on the actual working conditions of the tire unloader machine to obtain the time load history of the bearing. Transient dynamic analysis of the bearing was carried out to obtain the triaxial stress-strain time histories at the hazardous locations of the bearing. A new coordinate system was established using the hazard node as the coordinate origin, and the location of the critical plane was searched for based on the critical plane multiaxial fatigue theory, combined with the maximum shear strain amplitude on the critical plane for multi-axial rain flow cycle counting to obtain the damage amount in each direction. At the same time, the life calculated from the maximum damage amount was used as the final life, resulting in a cycle count of the bearing of 268,303 cycles and a duration of 1490.58h. The results of this study could be used as a guide to predict the service life of the bearing in large machinery subjected to multiaxial random stress conditions.

In order to reduce the number of hydraulic decoders and hydraulic control pipelines in hydraulically controlled intelligent wells, reduce production costs and improve oil recovery efficiency, the structural design of ICV control of two hydraulic control pipelines and a single hydraulic decoder for four production layers in the well was completed. By simulating the response law of downhole hydraulic signals and the stress analysis of each structure, the motion equation of the layer selection structure of the hydraulic decoder was established with 4 MPa as the unlocking pressure, and ADAMS was used to complete the dynamic simulation analysis. The variation results of displacement, angle, velocity and acceleration in the process of motion were obtained. Finally, the prototype of the hydraulic decoder was processed by stereo photo curing 3D printing equipment. Two hydraulic pumps were used to press alternately, and the selection of four layers of the hydraulic decoder was realized through two hydraulic control pipelines. The self-locking structure could realize the established function, and there was no interference and stuck between the components, which verifies the effectiveness of the design.

The main objective of this research is to formulate and couple technologies for modeling discrete and continuous media using real particle morphologies. To that end, two coupled formulations based on virtual modeling technologies of single real particles with another one called real particle packing technique are presented. The first formulation employs Fourier descriptors’ theory to virtually achieve the morphology and construct a repository of real particle geometries. The second formulation is a particle packing method, supported by advancing front techniques combined with dynamic methods. This method presents a stochastic formulation and allows the packing of particle systems following continuous, discrete and empirical statistical distributions. The coupling of both techniques is a very efficient tool to achieve discrete or continuous media geometries to solve engineering problems. Three different examples are developed to illustrate the usefulness of the formulations. The first one is a discrete angle-of-repose problem involving clusters of spheres (real particle morphologies are described with groups of spheres); in the second example the same angle-of-repose problem is resolved with real particles. In the third case, which involves continuous medium mechanics, a small-scale road engineering problem is modeled, specifically, the testing of an asphalt concrete.

An increase in container traffic, larger tonnage of vessels, scarcity of port area, and shorter turnaround times have driven terminals to process more containers in less time and less space. Thereby, the increasing focus on costs, safety, and environmental control is forcing terminal operators to search for innovative solutions. Automated container terminals are the potential candidates to improve the performance of container terminals and represent a challenge to any subsequent future fluctuations in maritime transport. In this study, we examine the improvement in the performance of container ports by adopting automation through simulation modeling. The effect of the automated guided vehicles and automatic stacking cranes-based automatic container terminal system (AGV-ACT/Automated Guided Vehicles - Automatic Container Terminal system) on container handling operations was evaluated. To create a complete port simulation model, the main objects of the container terminal such as tugboats, berths, quay cranes, stacking blocks, stacking cranes, horizontal transport vehicles, external trucks, and the layout of the terminal are simulated as a whole. Firstly, we created a model representing the existing port to evaluate the overall performance of the port and to validate the simulation model by comparing the actual data with those of the real system. Then, a simulation model for the proposed automatic system was created and evaluated. The simulation model was divided into four main logics: ships arrival and berth allocation, ship loading/unloading, external trucks arrival, and containers storage/retrieval logic. The results of the two systems were compared based on the performance criteria such as ship turnaround time, external trucks turnaround time, and equipment utilization rate. Automation has reduced the turnaround time of the ships and provided a smooth movement for the equipment which showed a high utilization rate. The automated system decreased the ship turnaround time from 9.52 hours to 7.81 hours (18%). The reduction in the waiting times of the container transport vehicles for quay cranes reached 47% and 30% in berths 1 and 2, respectively. On the other hand, external trucks’ turnaround time increased by 124% as only one ASC (Automatic Stacking Crane) is run in each block to perform both seaside and landside operations (seaside operations were prioritized). Automation has improved the overall performance of the terminal. Also, the layout of the automated handling system raised the storage capacity of the port. In the new proposed automated layout, the storage area capacity increased by 27.27%.

This paper presents an experimental and numerical investigation on the mechanisms of damage onset and evolution in unidirectional carbon fibre reinforced thermoplastic (CFRTP) composites subjected to off-axis compressive loadings. A test fixture was designed to prevent buckling, splitting and end collapsing of specimens during test. A series of compression tests were conducted with specimens of various off-axis angles. Different failure mechanisms and nonlinear stress-strain responses were observed and studied. The fracture angles of the tested specimens were evaluated and analysed according to Puck’s theory. The off-axis compression failure envelope based on LaRC05 and Hashin criteria was presented using finite element analysis and compared to experimental results. It is shown that the LaRC05 criterion can provide accurate predictions for matrix cracking failure mode of unidirectional thermoplastic composites controlled by compression-shear combined stresses.

For improving the energy efficiency of hopping robot, an asymmetric spring loaded inverted pendulum hopping model with leg mass is considered. The period orbit problem of two-legged hopping robot is investigated. Firstly, the hybrid dynamic model is constructed. Then the passive hopping gaits are found using quasi-newton optimization method. Secondly, a PD controller is implemented to track the desired pitch trajectory of the body. Through applying control during stance phase, period orbits of the robot with offset body mass is obtained. Finally, the effect of the location of the leg mass and the body mass on hopping performances is investigated.

Thestudyonthe assembly support for the large cantilevered cover beamwascarried outby conducting real-time monitoringon the assembly frames’ strain and displacement developmentprocesses in the actual project. Modeling of the support and numerical simulation for actual working conditionswere presented. The monitoring data and analysis results show that the overallstress ratioof the supportwasless than 30%.And asthe concrete structure being supported hardened, the support framewasunloaded. When the stress ratio was thenreduced to less than 10%, it was the most appropriate time to remove the bracing frame. The maximum strainfrom the simulationdidnot exceed 66.26% of the theoretical maximum strain of the rod. The actual construction conditions and the spatial form of the supportaffectedthe force situation, resulting in thedeviation from the theoretical maximum strainat certain phases. The analysis results and trends reflect the low utilisationrate of such framingrods. The results of the study can be used as a reference for the topology optimisation of assembled supportframes for large cantilevered cover beams.

'' This work aims to develop a computational tool for synthesizing a four-bar linkage mechanism that can generate a prescribed path for a point coupler link to follow. The dimensional synthesis of the mechanism involves determining the lengths of each of its links. In this case, two possible configurations are evaluated: crank-rocker and/or double crank. The prescribed path consists of an arbitrary number of points contained in a plane, along with the corresponding rotation degrees of the driver element.'' Dimensioning the mechanism involves many variables, and it is possible to obtain various configurations that generate paths that are approximately the desired path. Therefore, the synthesis problem arises as an optimization problem in which the objective function seeks to minimize the Euclidean norm between the prescribed points and the points earned. To solve the optimization problem, a user-friendly computer program called SIDIGETRA was developed using the genetic algorithms numerical technique. Design constraints were imposed to obtain an open configuration of the mechanism and to avoid branching defects, order, and Grashof. The program's proper functioning was validated by comparing the results obtained in case studies published in a research article in which the genetic algorithms technique was also applied. The percentage relative errors between the coordinates of the obtained points and prescribed points were calculated and found to be satisfactory. Additionally, the results generated by SIDIGETRA were validated with a visual comparison between the prescribed trajectory and the one obtained by simulating the position analysis of the synthesized mechanism using a commercial software tool designed for this purpose.

Bearing is an important rotating support part of tyre unloader, and its fatigue reliability is an important part of the whole system reliability. Because of the huge alternating stress, the support bearing is required to have high fatigue life and reliability. In this paper, combined with stress-strength interference model and statistical theory, the life distribution of bearing steel material is predicted by using group test data; Based on the multi-rigid body dynamics and finite element numerical simulation platform, the reliability of the bearing of tyre unloader under different operating years was predicted by using the different dimensional interference model. The results show that the maximum resultant force of the bearing at the bottom rocker arm of the tyre unloader can reach 150kN, and the maximum transverse and longitudinal forces can reach 108kN and 78kN. When bearing the weight of the whole tyre and turning, the inertia force is the largest, the maximum stress value is 1316.2MPa, which occurs in the bearing inner ring and ball contact part. After the statistics, the stress amplitude distribution of the bearing conforms to Weibull distribution, and the life of the bearing follows lognormal distribution. After 105 tyre unloading, the fatigue reliability of the bearing is lower than 0.82, which is consistent with the actual working condition. Therefore, this model can be used to calculate the fatigue reliability of bearings conveniently and quickly, and provide certain theoretical support for the safety and fatigue reliability prediction of bearings.

In order to solve the problem of "gas explosion" at the end of common rubber cylinder in the process of high temperature, high pressure and gas drive operation, the rubber cylinder with new structure suitable for 51/2 in casing pipe is developed. The "M" type single rubber cylinder structure is adopted in the new structure rubber cylinder, and the "gas explosion" problem of the end gas in the low-pressure side is solved by setting the double-layer staggered slotted steel cover to prevent outburst. The finite element method is used to simulate the setting of the rubber cylinder, and the structural parameters of the new rubber cylinder are obtained by single factor analysis and orthogonal optimization, simulation test and seal test were carried out to verify the sealing performance of the rubber cylinder. According to the actual working condition, the simulation test results and seal test results show that the sealing capacity of the packer reaches 50 MPa under the temperature resistance of 120℃, and the end steel cover is fully opened to wrap the rubber cylinder, which meets the operation requirements of high temperature and high pressure gas injection packer.

In this work we identify the coherent vortices in the leeward wake of an HQ 17 airfoil with a Gurney flap. This high-lift device consists of a small plate perpendicular to the airfoil, at or near the trailing edge, with a height � of the order from 1% to 4% of the chord. The overall effect is to produce a significant increase in lift, together with a relatively minor increase in airfoil drag. Its geometry generates vortex shedding of spatial scale H, which modulates the wake and thus influence the global configuration of the flow. A numerical study was performed with the commercial software ANSYS Fluent. Simultaneously, experiments were carried out in the wind tunnel of the Aeronautical Departmental Area from the Engineering School of the National University of La Plata. With a Dantec StreamLine hot-wire anemometer, records of the instantaneous horizontal and vertical velocity components in the airfoil wake were obtained. Both the experimental data and those obtained by numerical simulation were analyzed with the continuous wavelet transform technique, in order to identify and characterize the coherent vortices in the wake. Results show the shed vortices structure and the organization degree of this periodic shedding.

Metamaterials are generated from an interrelated set of cells and can present a macroscopic behaviour that differs from the one that characterizes its basic constituents. Modelling the influence that the damage and fracture of the elemental constituents have in the macroscopic properties of the metamaterial is relevant for its mechanical analysis. Altering the resistant behaviour of the elements (changing their longitudinal elastic modulus), it is possible to approximate the effect of the damage in the complete structure. It is considered as valid the substitution of the damage and plastic deformation phenomena by intermediate states contained in the linear elastic deformation regime. Each state is characterized by the elastic module of the element, whose geometry remains unmodified. In an iterative process, when the induced stress in the elements is greater than the one stablished as the limit, they progress through the different states, diminishing their elastic modulus until they are considered as fractured and are eliminated from the structure. Mass effects are ignored, and a stress-free structure is implemented to calculate each iteration. A simple algorithm is presented to simulate the effect of damage in metamaterial structures, applicable to any finite element software.

The water resources in southwest China is abundant and the seismicity is strong, so it is necessary to study the dynamic response and safety of hydraulic structures under rare earthquake. Taking a typical radial steel gate as an example, a three-dimensional numerical model considering the interaction between water and gate during the earthquake is established. The accuracy and applicability of the model are verified by comparing with the measured results of the dynamic response of Zipingpu dam during the Wenchuan earthquake. Thereafter, the dynamic displacement and stress, and resonance frequency of the radial gate under the rare earthquake of two wave types are analyzed. The water-structure coupling effect has a great influence on the seismic dynamic response of the radial steel gate. The calculated result of the dynamic response of the gate considering the fluid-structure coupling effect is significantly larger than that of the specification, and the maximum ratio of the two is more than 2.27 times. Under the action of EI wave, the peak value of dynamic stress response is at the bottom of the panel, and the maximum value of resonance frequency (about49.13 Hz) is located in the middle and lower part of the panel. Under the action of far-field wave, the peak area of dynamic displacement response of the gate is basically the same as that under the action of EI wave, while the maximum value of some measuring points is only half of the maximum value under the action of EI wave. However, the resonance frequency is significantly greater than that of EI wave, the maximum value reaches 65.24 Hz, which appears at the top of the gate. The dynamic response of the gate structure caused by two different wave types of earthquakes is not completely consistent. The comprehensive consideration of different wave types is of significance for the structural design and safety evaluation of the radial steel gate in the earthquake-prone areas.

This paper presents a novel approach for solving the security-constrained optimal power flow (SCOPF) optimization problem using parallel Computing. In this approach, switched shunt capacitors, generation power ramp, and demand response are considered in the SCOPF by maximizing the market surplus during regular operation and for a set of contingencies of branches and generators. The optimization problem is solved using the Nonlinear Interior Point Method. The contingency assessment is paralleled in multiple CPU cores to decrease the computation time. Additionally, the test systems used in ARPA-GO competition were used and compared with the ARPA benchmark results to assess the proposed algorithm. The numerical results show this method is suitable for fast SCOPF using paralleling Computing.

We present a combination of three dimensional (3D) solid elements and rotation-free beam elements for non-linear analysis of fiber-reinforced polymer (FRP) of rebars. The matrix material is modelled by 3D solid elements while the fibers are modelled with rotation-free beam elements. The absence of rotation variables in the beam elements allows the straightforward coupling of 3D solid and beam elements using a formulation with displacement nodal degrees of freedom only. Both solid and beam elements are formulated in an updated Lagrangian description. The behavior of the matrix and the fiber material are modelled with an elastic-damage model. The efficiency and accuracy of the combined 3D-beam element formulation are verified in examples of application to the analysis of FRP rebars up to fracture in axial, bending and shear tests for which experimental results are available.

The modeling of both the synchronous generator and induction motor which is represented by the rotor reference frame was studied where the modeling was established using MATLAB /SIMULINK software package for an isolated synchronous generator direct-on-line with different sized induction motors; 20, 50, and 100 Hp, at manually adjusted excitation voltage values which were maintained constant at 3.35, 4.55, and 6.21 V, respectively. The purpose of this work is to study the impact of a sudden increase in the load torque; from 0 to 150 % with an increase of 25 %, of full load torque was studied at a constant motor speed of 188.49 rad sec-1. On the other hand, the impact of a sudden decrease in the rotor speed by about 20 % from its rated value; from 188.49 to 150.79 rad sec-1 was also studied at full load torque of the same different-sized induction motors. These values were manually recorded and response variables of the generator including terminal voltage, current, output power, electromagnetic torque, and load angle were determined and represented as a function of time. The results illustrated the Changes in the terminal voltage, the current, the output power, the electromagnetic torque, and the load angle as parameters of a synchronous generator for different-sized induction motors.

The granular-media-based push-bending process has been developed to manufacture thin-wall elbow tube with t/D≤0.01 (the ratio of wall thickness to outer diameter) and R/D≤1.5 (the ratio of bending radius to outer diameter). In the process, a tubular blank is filled with granular media and then pushed into a die to form an elbow shape. To investigate the process, a FEM-DEM coupling model has been developed, in which FEM is used to simulate bending deformation of tubular blank, and DEM is used to calculate contact forces between spherical particles in granular media. In this work, an improved numerical formulation is proposed in order to reach mechanical equilibrium quickly and accelerate the convergence of DEM simulation, when the new contacts are no longer created and the old contacts are no longer deleted in granular media. Using the proposed numerical formulation, the improved FEM-DEM coupling simulation for granular-media-based thin-wall elbow tube push-bending process is less time-consuming than before under the same simulation condition.

Çalışma, Türkiye pazarındaki büyük göndericiler arasındaki farklılıkları ve benzerlikleri belirlemek için okyanus konteyner taşıyıcı seçim kriterlerini incelemiştir. Uygulama tekstil, beyaz eşya ve kimya sektörleri olmak üzere yüksek taşıma hacmine sahip üç farklı gönderici grup arasında yapılmıştır. Türkiye'de ilk kez yüksek kapasiteye sahip üç gönderici grubu ile çalışılmış bu gruplar arasındaki bakış açısı farklılıkları irdelenmiştir. Aynı zamanda bilgilimiz kadarıyla bu çalışma üç farklı yüksek kapasiteli gönderici grup arasındaki farklılıkları analiz etmek için bulanık Analitik Hiyerarşi Prosesi (AHP) yöntemini kullanan ilk çalışmadır. Bu yönüyle çalışma literatüre katkı sağlamayı amaçlamaktadır. Yapılan bulanık AHP uygulaması sonucunda önem ağırlıkları farklılık göstersede her üç sektör için en önemli ana kriter güvenirlilik olarak bulunmuştur.

In order to solve the problems of serious axial and tangential leakage and low torque density in the magnetic circuit axial permanent magnet gear (APMG), an external regulating ring is introduced on the basis of APMG to form a dual-excitation and modulation APMG structure, namely DEM-APMG. The low speed rotor of DEM-APMG is clamped between the inner and outer magnetizing rings to generate dual-excitation field (i.e. dual excitation). At the same time, the inner and outer magnetizing rings modulate the low speed rotor dual-directionally modulation (i.e. dual modulation). The axial and tangential leakage flux of APMG can be converted into useful harmonics to increase the output torque and torque density on the basis of APMG. In this study, mathematical analysis is used to describe the air gap magnetic density and electromagnetic torque model of a DEM-APMG, which essentially describes the root cause of the increase in torque density. Using 3D finite element static and dynamic simulations, the transmission characteristics of the APMG and DEM-APMG are compared and analyzed. Results show that the maximum static torque of the DEM-APMG high-speed and low-speed rotors with the same outer diameter increase by 22.7% and 23.8%, respectively, compared with APMG, 26% and 29%, respectively, in steady-state operation, and the torque density increases by 24%. The influence of the primary structural parameters on the transmission characteristics is also investigated using the control variable method. Results show that the duty cycle of the magnet adjusting block, the axial length of the high-speed permanent magnet and the low-speed permanent magnet have the strongest effect on the torque density of the DEM-APMG. When the axial length of the high-speed permanent magnet and low-speed permanent magnet is 8mm, and the duty cycle is 0.4, the torque density can reach the optimal value of 156kNm/m3.

In this study, IGA is introduced into the performance analysis of the expansion water seal for an exact representation of its complex geometrical shape. Firstly, the incremental equilibrium equations used in the large deformation analysis are derived for the IGA discretization model based on the updated Lagrangian formulation. The unknown contact forces are directly involved in the equilibrium equations, which results in a simple expression. Then, through the investigation of the contact conditions, the normal and tangential contact forces are verified to be the solutions of two box-constrained variational inequalities representing the normal and tangential contact conditions, respectively. Furthermore, the incremental equilibrium equations for all components of the water seal system and the variational inequalities for all contacts between the components are assembled together and reformulated as a global variational inequality, which is resolved by using the Extra-gradient method. Ultimately, the new method is applied in the performance comparison of two optional expansion water seals, in which the capability and precision of the proposed method are investigated. Results verify that the proposed method is effective in the numerical simulation of the expansion water seal and has a higher precision than the traditional FEM under the same conditions.

Çin'in Wuhan eyaletinde, ilk kez 2019 Aralık ayında görülmeye başlayan ve 2020 yılının ilk aylarında tüm dünyayı tehdit eden, Dünya Sağlık Örgütü tarafından pandemi olarak isimlendirilen Covid-19, dünya çapında çok büyük ekonomik kayıplara sebep olmuş ve ülke ekonomilerini zarara uğratmıştır. Uygulanan kısmi veya tam kapanmalarla birlikte ulaşımın dünya çapında birçok noktada durdurulması, ülkelere giriş ve çıkışların yasaklanmasıyla küresel çapta ekonomik faaliyetler neredeyse durma noktasına gelmiştir. Salgın sadece insan sağlığını değil, paralelinde dünya ticaretini de olumsuz yönde etkilemiştir. Salgının yayılmasını önlemek amacıyla ülkelerin uyguladıkları karantina tedbirleri sonucunda fabrikalar kapanmış ve uygulanan sıkı gümrük kontrolleri nedeniyle dış ticaret ciddi ölçüde etkilenmiştir. Küresel çapta ortaya çıkan arz-talep dengesindeki bozulma hem üretim hem de tüketimin daralmasına neden olmuştur. Özellikle tedarik zincirinde yaşanan aksamalardan dolayı tüm dünyada ithalat ve ihracat faaliyetleri durma noktasına gelmiştir. Covid-19 pandemisi sürecinin beraberinde getirdiği olumsuz etkilerin oldukça yoğun bir şekilde hissedildiği sektörlerden biri de, hiç şüphesiz deniz ticaretidir. Uluslararası ticarette taşımacılık faaliyetleri, büyük oranda ekonomik oluşu nedeniyle denizyolu ile gerçekleştirilmektedir. Denizyolu taşımacılığı uluslararası ticaret ve küresel ekonominin temel direğini oluşturmaktadır. Gemilerin, güzergahları boyunca dünyanın çok farklı bölgelerinde bulunan limanlara uğraması nedeniyle salgının ortaya çıktığı ilk zamanlardan itibaren denizcilik sektörü üzerindeki etkileri hissedilmeye başlanmıştır. Türk denizcilik sektörü de bu pandemi sürecinden derinden etkilenmiştir. Bu çalışma da, Türkiye’de 2020 yılının Mart ayında devlet tarafından ilk vakanın açıklanmasıyla başlayan Covid-19 pandemisi, Türkiye’nin deniz ticareti sektörüne olan etkisi, TCMB ödemeler dengesinde bulunan navlun, navlun ve sigorta, ihracat (f.o.b) ve ithalat (c.i.f) verileri ışığında yorumlanmıştır. Bu veriler, 2010-2022 dönemi için TCMB EVDS veri tabanından temin edilmiş olup, değerlendirme için durum analizi yapılmıştır. Çalışma bulgularına göre pandemi sürecinde Türkiye’de navlun değeri sürekli düşüş gösterirken, ihracat (f.o.b) ve ithalat (c.i.f) değerleri sürekli artmıştır. Ancak ihracat (f.o.b) yükselişi, ithalat (c.i.f) değerleri karşısında yinede istenilen düzeyde değildir., The world was endangered by Covid-19, which first surfaced in the Chinese province of Wuhan in December 2019 and was dubbed a pandemic by the World Health Organization. It caused significant economic losses globally and hurt the economies of the nations. With the partial or full closures implemented, the suspension of transportation at many points around the world and the prohibition of entry and exit to countries, global economic activities have almost come to a standstill. Along with negatively affecting human health, the outbreak has also had an impact on global trade. Factories were shut down as a result of the quarantine measures countries enacted to stop the pandemic from spreading, and foreign trade was severely hampered by the rigorous customs controls enforced. The deterioration in the supply-demand balance that emerged on a global scale caused both production and consumption to shrink. Imports and exports have ceased entirely, particularly as a result of supply chain problems. These negative effects have thrown off the world's supply chain.Undoubtedly, one industry where the Covid-19 pandemic process is having a negative impact is marine trade. Due largely to its economic nature, shipping activities in international trade are typically conducted by sea. Maritime transport is the cornerstone of international trade and the global economy. The effects of the epidemic on the maritime sector have been felt since the early days of the epidemic, as ships call at ports located in many different parts of the world along their routes. The Turkish maritime industry has also been deeply affected by this pandemic process.This study examines the effects of Covid-19, which became evident in Turkey in March 2020, on Turkey's maritime trade sector, was interpreted in the light of the CBRT balance of payments, freight and insurance, export (f.o.b) and import (c.i.f) data. These data were obtained from the CBRT EDDS database for the period 2010-2022, and a situation analysis was made for evaluation. According to the findings of the study, while the freight value decreased continuously in Turkey during the pandemic process, the export (f.o.b) and import (c.i.f) values increased continuously. However, the increase in exports (f.o.b) is still not at the desired level against import (c.i.f) values.

The main objective of FIBRE4YARDS project is to maintain European global leadership in ship building and ship maintenance, through implementation of the Shipyard 4.0 concept in which advanced and innovative FRP manufacturing technologies are successfully introduced. This project has received funding from European Union's Horizon 2020 research and innovation programme under grant agreement n°101006860.

The main objective of FIBRE4YARDS project is to maintain European global leadership in ship building and ship maintenance, through implementation of the Shipyard 4.0 concept in which advanced and innovative FRP manufacturing technologies are successfully introduced. This project has received funding from European Union's Horizon 2020 research and innovation programme under grant agreement n°101006860.

The main objective of FIBRE4YARDS project is to maintain European global leadership in ship building and ship maintenance, through implementation of the Shipyard 4.0 concept in which advanced and innovative FRP manufacturing technologies are successfully introduced. This project has received funding from European Union's Horizon 2020 research and innovation programme under grant agreement n°101006860.

The main objective of FIBRE4YARDS project is to maintain European global leadership in ship building and ship maintenance, through implementation of the Shipyard 4.0 concept in which advanced and innovative FRP manufacturing technologies are successfully introduced. This project has received funding from European Union's Horizon 2020 research and innovation programme under grant agreement n°101006860.