Real Size Research Articles

Predicting the Spatial Distributions of Elements in Former Military Operation Area Using Linear and Nonlinear Methods Across the Stavnja Valley, Bosnia and Herzegovina

This study has the purpose of developing a realistic soil prediction maps of the spatial distribution of elements by evaluating and comparing different modelling techniques: Kriging, artificial neural network-multilayer perceptron (ANN-MLP) and multiple polynomial regressions (MPR). The Stavnja Valley was selected as a test area due to the following reasons: (1) intensive metal ore mining and metallurgical processing; (2) peculiar geomorphological natural features; (3) regular geological setting, and (4) the remaining minefields. Geospatial parameters from digital elevation models (DEM) are used as an input to advanced prediction modelling techniques: ANN-MLP and MPR. Soil measurements, land use data, and remote sensing are applied, developed, and finally incorporated into the models of spatial distribution in the form of 2D or 3D maps. In order to reconstruct the different processes that influenced the entire study area simultaneously, we used novel approaches to modelling. This comprehensive approach not only represents an innovation in contamination mapping, but developed prediction models also help in the reconstruction of main distribution pathways, assess the real size of the affected area, and improve the data interpretation.

Transposition of the mechanical behavior from model to prototype of Francis turbines

Hydropower is nowadays essential for balancing the electrical grid providing flexibility and fast response. The role of hydraulic turbines has changed from working at their Best Efficiency Point (BEP) to work in the whole operating range when demanded. Francis turbines working at off-design conditions suffer from dynamic problems that affect the useful life of their components, especially of the runner.Reduced scale physical models of Francis turbines are widely used to determine their hydraulic behavior. Most of the hydraulic parameters obtained in model tests are transposable to prototype by using the similarity theories as long as they meet similitude requirements. However, from the mechanical behavior point of view, both model and prototype structures are not always similar and the mechanical behavior of the model is often not considered for transposition.In this paper, a transposition method for the mechanical behavior of Francis turbines models is presented and the results are compared with the real size prototype. The modal behavior of the runner, its stress and fatigue life estimation for different operating conditions are experimentally compared for both model and prototype. Results present the possibilities and limitations of transposing the mechanical parameters from model to prototype.

Force chains based mesoscale simulation on the dynamic response of Al-PTFE granular composites

Force chains based mesoscale simulation is conducted to investigate the response behavior of aluminum-polytetrafluoroethylene (Al-PTFE) granular composites under a low-velocity impact. A two-dimensional model followed the randomly normal distribution of real Al particles size is developed. The dynamic compressive process of Al-PTFE composites with varied Al mass fraction is simulated and validated against the experiments. The results indicate that, force chains behavior governed by the number and the size of agglomerated Al particles, significantly affects the impact response of the material. The failure mode of the material evolves from shear failure of matrix to debonding failure of particles with increasing density. A high crack area of the material is critical mechanism to arouse the initiation reaction. The damage maintained by force chains during large plastic strain builds up more local stresses concentration to enhance a possible reaction performance. In addition, simulation is performed with identical mass fraction but various Al size distribution to explore the effects of size centralization and dispersion on the mechanical properties of materials. It is found that smaller sized Al particle of composites are more preferred than its bulky material in ultimate strength. Increasing dispersed degree is facilitated to create stable force chains in samples with comparable particle number. The simulation studies provide further insights into the plastic deformation, failure mechanism, and possible energy release capacity for Al-PTFE composites, which is helpful for further design and application of reactive materials.

Intradural Extramedullary Plasmacytoma in a Dog

Background: Plasmacytoma is a neoplasm originating in plasma cells, derived from B lymphocytes. Extramedullary presentation is the most common form of plasmacytoma, mainly in the skin and rarely in other tissues, including the vertebral canal. Extramedullary plasmacytoma (EMP) occurs more frequently in senile dogs and rarely in cats and some dog breeds have predisposition for this type of neoplasm. The aim of this study was to report plasmacytoma in a dog located adjacent to the thoracic vertebrae.Case: An approximately 5-year-old mongrel male with sudden paraplegia resulting from upper motor neuron injury was admitted to a University Hospital. The dog presented a six-centimeter diameter mass in the dorsal region, adjacent to the thoracic vertebrae. The leucogram presented mild leukopenia by eosinopenia and lymphopenia. Myelogram associated with epidurography showed a fill failure in the contrast column between the seventh and ninth thoracic vertebrae, and there were no osteolysis points in the thoracic vertebrae, adjacent to the neoplastic mass. The evaluation of the intervertebral spaces between the fourth to ninth thoracic vertebrae presented no increase in radiopacity, nor alterations in the size of intervertebral spaces, indicating intervertebral disc extrusion. The laterolateral radiographs showed an alignment of the vertebrae and vertebral canal, without presence of bone neoformations on the ventral face of the vertebral bodies. The animal was euthanized and fragments of mass were collected for histological analysis. Macroscopic findings presented a non-encapsulated well-delimited mass, with color ranging from white to reddish. Microscopically, there was proliferation of moderately differentiated round cells in bone and muscle tissues, arranged in mantle, with moderately eosinophilic cytoplasm, and rounded nucleus with eccentric location, coarse chromatin sometimes indistinct. These cells presented moderate anisocytosis and, in general, one mitosis per field. Intradural extramedullary plasmacytoma was diagnosed.Discussion: The present report presented a diagnosis of intradural EMP, generating compression of the spinal cord because of its invasive growth, reaching the canal and, thus, reducing its lumen. The clinical status of the dog was compatible with thoracolumbar lesion of upper motor neuron, which causes paresis and ataxia in pelvic limbs. In this case, it was not possible to establish early diagnosis because the dog had been rescued from the streets recently. Radiographic examination was important to identify the real size of the mass, and the myelography confirmed spinal cord compression. The definitive diagnosis was obtained by histological examination. Although extramedullary plasmacytoma is a low-frequency neoplasm, in the present report, its manifestation was atypical, more aggressive, invading the medullary canal and compressing the spinal cord. Spinal cord compression may lead to degeneration of axons because of alterations in the vascular permeability associated with local inflammatory process, reducing the oxygen supply to nervous tissues, resulting in cellular degeneration. The occurrence of atypical neoplastic growth should be included as a differential diagnosis for lesions in upper motor neuron in cases of spinal cord compression. This is an atypical location for this kind of neoplasia, and cases of medullary compression of neoplastic masses should be included as a differential diagnosis.

A post-contingency power flow emulator for generalized probabilistic risks assessment of power grids

Risk-based power dispatch has been proposed as a viable alternative to Security-Constrained Dispatch to reduce power grid costs and help to better understand of prominent hazards. In contrast to classical approaches, risk-based frameworks assign different weights to different contingencies, quantifying both their likelihood occurrence and severity. This leads to an economically profitable operational schedule by exploiting the trade-off between grid risks and costs. However, relevant sources of uncertainty are often neglected due to issues related to the computational cost of the analysis. In this work, we present an efficient risk assessment frameworks for power grids. The approach is based on the Line-Outage Distribution Factors for the severity assessment of post-contingency scenarios. The proposed emulator is embedded within a generalized uncertainty quantification framework to quantify: (1) The effect of imprecision on the estimation of the risk index; (2) The effect of inherent variability, aleatory uncertainty, in environmental-operational variables. The computational cost and accuracy of the proposed risk model are discussed in comparison to traditional approaches. The applicability of the proposed framework to real size grids is exemplified by several case studies.

Data Enhancement for Plant Disease Classification Using Generated Lesions

Deep learning has recently shown promising results in plant lesion recognition. However, a deep learning network requires a large amount of data for training, but because some plant lesion data is difficult to obtain and very similar in structure, we must generate complete plant lesion leaf images to augment the dataset. To solve this problem, this paper proposes a method to generate complete and scarce plant lesion leaf images to improve the recognition accuracy of the classification network. The advantages of our study include: (i) proposing a binary generator network to solve the problem of how a generative adversarial network (GAN) generates a lesion image with a specific shape and (ii) using the edge-smoothing and image pyramid algorithm to solve the problem that occurs when synthesizing a complete lesion leaf image where the synthetic edge pixels are different and the network output size is fixed but the real lesion size is random. Compared with the recognition accuracy of human experts and AlexNet, it was shown that our method can effectively expand the plant lesion dataset and improve the recognition accuracy of a classification network.

Mechanical response and damage mechanism of cement sheath during perforation in oil and gas well

Perforation will damage the cement sheath around the hole in petroleum engineering, leading to the failure of cement sealing integrity during hydraulic fracturing. This work presents a perforating experiment in real size to investigate the damage mechanism of cement sheath. The crack characteristics inside the cement after perforation were statistically analyzed by computerized tomography (CT). Then, a numerical model was introduced to describe the effective stress state in cement sheath during perforation based on ANSYS/LS-DYNA software. The damage zone around the hole in cement sheath was partitioned by the peak stress of cement during perforation. The results show that damage zone was formed by the surface pressure around the hole after the shaped jet passed through the cement. The toothed micro-cracks around the tapered hole are close to the cement/formation interface. The cement with lower shear modulus and higher strength can reduce the damage range in cement sheath, and the scheme with lower perforation density and larger perforated phase is more effective to the maintenance of cement sealing integrity during later fracturing process.

Comparative modelling of indirect tensile strength of asphalt mixtures with and without considering air void characteristics

ABSTRACT This paper aims at comparing the 3D discrete element modelling of the indirect tensile (IDT) strength of asphalt mixtures with and without considering the air void size and distribution. Micromechanical models for predicting the IDT strength of asphalt mixtures, with and without considering the air void size and distribution, were established using X-ray computed tomography and 3D discrete element method (DEM) incorporated with a cohesive zone model (CZM). The IDT strength of three asphalt mixtures were simulated at three different temperatures on the basis of these models. Simulation results were verified against known experimental IDT tests. The results show that air void characteristics affected greatly the IDT strength of asphalt mixtures, and with the same material parameters, the IDT strength with considering the real air void size and distribution was lower and closer to the experimental IDT strength than that without considering the real air void size and distribution. Furthermore, aggregate size and temperature also significantly affected the IDT strength. IDT strength increased with increasing aggregate size or decreasing temperature. Aggregate size had an increased impact on the IDT strength with increasing temperature, whereas air void characteristics had a decreased influence on the IDT strength with increasing temperature.

Reentrant hybrid flow shop scheduling problem with non-anticipatory sequence-dependent setup time

This paper studies a hybrid flow shop scheduling problem originated from a steam turbine rotor production. Reentrance and non-anticipatory sequence-dependent setup time are considered. The objectives are to minimise makespan and total tardiness. A mixed integer linear programming model is formulated. A bi-objective simulated annealing algorithm is developed to solve problems with real size. A modified version of the Nawaz-Enscore-Ham algorithm is applied to find a good initial solution and a Pareto search mechanism is introduced to find the Pareto set. The proposed bi-objective simulated annealing algorithm is compared with a single-objective algorithm. Experimental results demonstrate the superiority of the bi-objective algorithm. Sensitivity analysis provides valuable managerial insights for real production.

HISTORICAL DESIGN OF CANTILEVER SHELLS OF MODERNIST ARCHITECTURE

Introduction : Studying the historical design system of the pioneer concrete shells helps to reveal a relevant part of the History of Construction, which is also fundamental in acquiring the knowledge necessary to conserve and restore this iconic heritage. Cantilevered shells, like large domes, have been the most difficult to design and dimension when computers did not yet exist. Methods: The research included two phases: firstly, the selection and analysis of some of the most relevant pioneer cantilevered shells, and secondly, the comparative analysis of their design systems. Result and discussion: The analysis pointed out that the pioneer master engineers used different design systems. Pier Luigi Nervi and Eduardo Torroja mainly used scale model tests to check the structural behavior of their new continuous structural forms, Ildefonso Sanchez del Rio always used ribbed shells and chose geometric forms that were easy to calculate manually, and Felix Candela used real size models for the tests. The result reveals the different paths that they used to design and build their relevant legacies, which nowadays belong to the international heritage of Modernist Architecture.

Measurement of inside flow of diesel injector by using real size transparent nozzle

Measurement of inside flow of diesel injector by using real size transparent nozzle

System Assessment of WUSN Using NB-IoT UAV-Aided Networks in Potato Crops

Unmanned Aerial Vehicles (UAV) are part of precision agriculture; also, their impact on fast deployable wireless communication is offering new solutions and systems never envisioned before such as collecting information from underground sensors by using low power Internet of Things (IoT) technologies. In this paper, we propose a (Narrow Band IoT) NB-IoT system for collecting underground soil parameters in potato crops using a UAV-aided network. To this end, a simulation tool implementing a gateway mounted on a UAV using NB-IoT based access network and LTE based backhaul network is developed. This tool evaluates the performance of a realistic scenario in a potato field near Bogota, Colombia, accounting for real size packets in a complete IoT application. While computing the wireless link quality, it allocates access and backhaul resources simultaneously based on the technologies used. We compare the performance of wireless underground sensors buried in dry and wet soils at four different depths. Results show that a single drone with 50 seconds of flight time could satisfy more than 2000 sensors deployed in a 20 hectares field, depending on the buried depth and soil characteristics. We found that an optimal flight altitude is located between 60 m and 80 m for buried sensors. Moreover, we establish that the water content reduces the maximum reachable buried depth from 70 cm in dry soils, down to 30 cm in wet ones. Besides, we found that in the proposed scenario, sensors’ battery life could last up to 82 months for above ground sensors and 77 months for the deepest buried ones. Finally, we discuss the influence of the sensor’s density and buried depth, the flight service time and altitude in power-constrained conditions and we propose optimal configuration to improve system performance.

Conditions and Possibilities of Long-Term Public Debt Management

The socio-economic situation of many countries in a market economy environment still faces new barriers that significantly reduce economic potential and productivity, and negatively affect future development opportunities at local and national level. At present, it is still not possible to eliminate a number of factors that lead to the cyclical development of the market economy, as evidenced by the occurring crisis phenomena, a decline in the expected growth rate of gross domestic product, stagnation and even reduction of individual consumption and many other consequences. Public debt has become a serious problem in highly developed countries, and its size now raises a number of doubts about further sustainable development. From the point of view of achieving the strategic development goals, the existence of public debt may prove to be a particularly dangerous factor. The purpose of this paper is to draw attention to the real size of public debt and its impact on the economy in selected countries of the world, as well as to indicate directions for assessing the needs of effective public debt management in the long term. This problem results from the fact that the current volume of public debt in many countries of the world means that this debt cannot be significantly reduced in the short or medium term. As a result, it is necessary to adopt a long time horizon for public debt analysis and to adopt strategic management methods to reduce the negative impact of public debt on socio-economic development.

El Potro Desempotrado: el caballo ibérico de la Covatilla (Marchena, Sevilla)

El caballo ibérico de La Covatilla (Marchena), actualmente conservado en el Museo Arqueológico Provincial de Sevilla, fue publicado cuando se encontraba encastrado en la pared de un edificio de dicha localidad. Su extracción en los años ochenta ha permitido reconocer una serie de elementos hasta entonces ocultos que se relacionan con un arnés ecuestre correspondiente al tiro de un vehículo. Se convierte, así, en la primera escultura ibérica de gran formato que incluiría un carro. Se adscribe a un monumento conmemorativo relacionado con la ideología militar propia de la aristocracia ibérica.

3D Landscape Recording and Modeling of Individual Trees

The 3D city/landscape model is digital representation of real environment that can be used for planner or landscape architecture in urban development planning. That model’s more focused on building, whereas vegetation model’s also needed for urban planning simulation. This research purposes are to map existing vegetation and to generate individual trees model in some level of details. The research area is campus of ITB Jatinangor and the used data are orthophoto and DSM from UAV-Photogrammetry technology. Manual segmentation, classification, and NDSM generation process can provide tree information (position, crown diameter, species, height)-as 3D vegetation modeling input. It’s also necessary to provide classification, information, detail level, and visualization of vegetation model according to landscape architecture analysis needs. This research results are 3D vegetation models in LoD 1-3 with differents information based on appearance, geometry, semantic, and topology aspects of CityGML. Models then tested qualitatively based on visualization and sun shadow analysis. For visualization, the used data only able to generate LoD 1 and 2 vegetation model and the minimum LoD required for sun shadow analysis is LoD 2. Terrestrial data, which provide the real form and size of each tree part, is needed to generate LoD 3 vegetation model.

Mitigating bioenergy-driven biodiversity decline: A modelling approach with the European brown hare

The cultivation of energy crops leads to direct and indirect land use changes that impair the biodiversity of the agricultural landscape. In our study, we analyse the effects of mitigation measures on the European brown hare (Lepus europaeus), which is directly affected by ongoing land use change and has experienced widespread decline throughout Europe since the 1960s. Therefore, we developed a spatially explicit and individual-based ecological model to study the effects of different landscape configurations and compositions on hare population development. As an input, we used two 4 × 4 km large model landscapes, which were generated by a landscape generator based on real field sizes and crop proportions and differed in average field size and crop composition. The crops grown annually are evaluated in terms of forage suitability, breeding suitability and crop richness for the hare. In six mitigation scenarios, we investigated the effects of a 10 % increase in the following measures: (1) mixed silphie, (2) miscanthus, (3) grass-clover ley, (4) alfalfa, (5) set-aside, and (6) general crop richness. All mitigation measures had significant effects on hare population development. Compared to the base scenario, the relative change in hare abundance ranged from a factor of 0.56 in the grass-clover ley scenario to -0.16 in the miscanthus scenario. The mitigation measures of mixed silphie, grass-clover ley and increased crop richness led to distinct increases in hare abundance in both landscapes (> 0.3). The results show that both landscape configuration and composition have a significant effect on hare population development, which responds particularly strongly to compositional changes. The increase in crop diversity, e.g., through the cultivation of alternative energy crops such as mixed silphie and grass-clover ley, proves to be beneficial for the brown hare.

A method of perspective normalization for video images based on map data

ABSTRACTObjective perspective distortion is a problem that needs to be solved by video surveillance analysis. Compared with the street scene method, which depends on prior knowledge of the scene or 3D scene of the dedicated hardware recovery scene, the commonly used perspective distortion correction method is based on the linear relationship to monitor a video image in perspective normalization. However, the distortion caused by perspective imaging is nonlinear, and the linear perspective normalization model cannot guarantee the accuracy of the correction in the scene where the perspective phenomenon is evident. An image normalization method based on map data is proposed to solve this problem. A nonlinear perspective correction model is introduced by establishing a single relation between video image space and map space. With selected control points between image and map, we can calculate homography matrix in order to build the perspective correction model, which is computed to know the single pixel real size in map. The proposed perspective correction model is applied to the moving target detection. The results of the linear correction model and the proposed nonlinear correction model prove the validity and practicability of the method.

Influence of Angle on Plate Penetration into Dense Granular Materials (Large-scale DEM Simulation Using Real Particle Size)

Influence of Angle on Plate Penetration into Dense Granular Materials (Large-scale DEM Simulation Using Real Particle Size)

Estimation equations for the height of Colombian elders using knee height

ResumenIntroducción. La estatura en el anciano no refleja su talla real de adulto joven debido al envejecimiento de su columna vertebral, entre otros aspectos.Objetivo. Proponer ecuaciones para estimar la talla de los ancianos colombianos mediante la altura de la rodilla, según el grupo étnico y el sexo. Materiales y métodos. Se hizo un análisis secundario del estudio transversal SABE 2015, utilizando un diseño muestral probabilístico y multietápico en personas colombianas de 60 o más años. Se seleccionaron aleatoriamente dos grupos de la base de datos del estudio SABE: el grupo para el desarrollo de las ecuaciones y el grupo para su validación. Se hizo un análisis de regresión lineal múltiple para estimar la estatura mediante la altura de la rodilla en los grupos étnicos (indígenas, afrodescendientes y blancos-mestizos) por edad y sexo; los resultados se validaron en cada subgrupo de estudio. Resultados. Se diseñaron seis ecuaciones por sexo (hombres=3.665, mujeres=3.019) y etnia; los coeficientes de determinación ajustados (R2 ) de las ecuaciones en hombres de los tres grupos étnicos oscilaron entre 64 y 75 % y, los errores estándar, entre 3,09 y 3,93 cm. En las mujeres, los R2 de las tres ecuaciones fluctuaron entre 53 y 73 % y los EE, entre 2,96 y 3,90 cm.Conclusión. La ecuación con mejor capacidad para estimar la talla del anciano colombiano fue la obtenida para los afrodescendientes de ambos sexos, en tanto que en la población indígena se presentaron los menores coeficientes de determinación.

A generalized model for gas flow prediction in shale matrix with deduced coupling coefficients and its macroscopic form based on real shale pore size distribution experiments

As an unconventional natural gas resource, shale gas is attracting increasing attention worldwide because of its potential to strengthen global energy security and reduce carbon emissions. The shale gas flow in nanopores is one of the main concerns affecting its development process. However, due to the strong nonlinearity and complexity of gas flow at the nanoscale, there is no satisfactory consensus on a physically sound flow mechanism scheme and its corresponding coupling method. Furthermore, although the integration method using specific functions has been proposed to facilitate the consideration of various pore sizes in shale matrix, the real shale experiments are rarely involved to realize this integration method with definitely determined parameters. In this study, the concept of “wall-associated diffusion” is firstly utilized to clarify the relationship among several flow mechanisms, and thereby a comprehensive flow mechanism scheme differing from common research is proposed, which physically considers both the division of mechanical mechanisms in nanopores and partition of flow space. Besides, the deficiencies in the mathematical models of viscous flow and several diffusion processes for flow description are illustrated. Using the molecular collision frequency expressions, a new coupling coefficient-based flow model in nanopores is derived to eliminate the aforementioned deficiencies by strengthening the correspondence between the flow models and Knudsen number (Kn), which is applicable in the full flow regime scope and avoids segment processing. Furthermore, based on the pore size distribution experiments of the real shale samples from a gas field, the fitting parameters needed for the macroscopic form of the above coupled model are obtained, so as to establish an integration method-based unified model for gas flow prediction in shale matrix. Results show that the prediction accuracy of the new model for the two tested shale samples is at least 2.2 times higher than several typical models and is also 1.9 and 7.5 times more accurate than the model without coupling coefficients, respectively. And the application of the proposed model to the flow experiment on another shale sample at higher pressure levels is in accordance with these observations. Interestingly, as temperature increases, the flow rate decreases with minor amplitudes. Under the conditions studied, the pressure change can cause over 10 times variation of the flow rate, revealing measures should be taken to maintain relatively high reservoir pressures to guarantee appreciable gas production from matrix if the other factors remain unchanged. In addition, the difference between the average flow shape in the whole rock and the gas motion in the pore of mean radius is revealed. Sounder in theoretical bases and better in application effects, the proposed model is expected to be of practical significance for guiding shale gas reservoir development.