Export 9208 results:
Sort by: Author Title Type [ Year  (Desc)]
2019
Park, J., Y. Lee, P. J. Currie, Y. Kobayashi, E. B. Koppelhus, R. Barsbold, S. Lee, S. Kim, and O. Mateus Three new skulls of the Late Cretaceous armored dinosaur Talarurus plicatospineus Maleev, 1952. Journal of Vertebrate Paleontology, Program and Abstracts., 2019.park_et_al_2019_svp_abstract.pdf
Ozer, Ezgi, Ozan Kocadagli, and Arnaldo Batista. "Time-Frequency Analysis of the EEG Signals: Visual Identification of Epileptic Patterns." y-BIS Conference . Mimar Sinan Fien Arts University/ Findikli Campus, 2019.
F. Queda, G.Covas, Silva A.Santos R.Bronze Javier Cañada Filipe Manuel Marques T. C. M. F. "A top-down chemo-enzymatic approach towards N-acetylglucosamine-N-acetylmuramic oligosaccharides: Chitosan as a reliable template." Carbohydr. Polym.. 224 (2019): 115133.
Lopes, A. C., E. B. Rodrigues, and R. Vera-Cruz. "Tourism Gentrification." IOP Conference Series: Materials Science and Engineering. 2019.
Antão, Nunes A., N. M. C. Guerra, Vicente M. da Silva, and T. Santana Upper and lower bounds for the bearing apacity of foundations on soft soils with reinforcement columns. Proceedings of the 17 th European Conference on Soil Mechanics and Geotechnical Engineering. Reykjavik, Islândia, 2019.
Mulenga, A., M. Faias, P. Mota, and J. P. Pina. "What happens when the stock markets are closed?" Electronic Journal of Applied Statistical Analysis. 12.2 (2019): 405-415. AbstractWebsite

The normality of the log-return of stock prices is often assumed by the market players in order to use some useful results, as for instance, the Black-Scholes formula for pricing European options. However, several studies regarding different indexes have shown that the normality assumption of the returns usually fails.
In this paper we analyse the normality assumption for intra-day and inter-day log-returns, comparing opening prices and/or closing prices for a large number of companies quoted in the Nasdaq Composite index. We use the Pearson's Chi-Square, Kolmogorov-Smirnov, Anderson-Darling, Shapiro-Wilks and Jarque-Bera goodness-of-fit tests to study the normality assumption.
We find that the failure rate in the normality assumption for the log-return of stock prices is not the same for intra-day and inter-day prices, is somewhat test dependent and strongly dependent on some extreme price observations.
To the best of our knowledge, this is the first study on the normality assumption for the log-return of stock prices dealing simultaneously with a large number of companies and normality tests, and at the same time considering various scenarios of intra-day, inter-day prices and data trimming.

Karlovich, Alexei Yu., and Eugene Shargorodsky. "When does the norm of a Fourier multiplier dominate its L-infinfty norm?" Proceedings of the London Mathematical Society. 118 (2019): 901-941.Website
Bedon, C., M. Arrigoni, F. Santos, and L. Figuli. "Advancements in design and analysis of protective structures 2019." Advances in Civil Engineering. 2019 (2019). AbstractWebsite
n/a
Peres, Ricardo Silva. "Agent-based Plug and Produce Cyber-Physical Production System – Test Case." 2019 IEEE 17th International Conference on Industrial Informatics (INDIN). 2019. Abstract
n/a
Schulp, AS, O. Mateus, M. Polcyn, Gon{\c A. c}alves, and LL Jacobs Angola and its role in the paleobiogeography of Gondwana. Journal of Vertebrate Paleontology, Program and Abstracts., 2019. Abstract
n/a
Marques, Filipe, Frank Coolen, and Tahani Coolen-Maturi. "Approximations for the likelihood ratio statistic for hypothesis testing between two Beta distributions." Journal of Statistical Theory and Practice. 13 (2019): 17. Abstract
n/a
Peres, Ricardo Silva Architectural Elements: PERFoRM Data Model. Digitalized and Harmonized Industrial Production Systems., 2019. AbstractWebsite
n/a
Gouveia, Nuno D., Duarte M. V. Faria, and António Pinho Ramos. "Assessment of SFRC flat slab punching behaviour – part I: monotonic vertical loading." Magazine of Concrete Research. 71 (2019): 587-598. AbstractWebsite

This paper presents a study of the behaviour and load capacity of steel-fibre-reinforced concrete (SFRC) flat slabs under monotonically increased concentrated vertical loads. The SFRC was used only in the local region of the slab–column connection, as the rest of the slab was cast using normal concrete without fibres. The six experimental test specimens had a thickness of 150 mm with different longitudinal reinforcement ratios, using a non-uniform distribution over the slab width. The concretes used were made with different Dramix 4D 65/60 BG steel fibre contents (0, 0·5, 0·75 and 1·0% volume content). The slab tests were complemented by flexural tests on notched beams. This made it possible to determine the tension behaviour of the different concretes used, through a linear post-cracking behaviour and inverse analysis. The inverse analysis made it possible to define the stress–crack opening relationship that characterises the tension behaviour of SFRC and to relate it to the observed behaviour and load capacity of the tested slabs. The tests results show that the tensile behaviour of the SFRC plays an important role in the behavioural and load capacity of the slabs and that it can be considered relevant to physically based models.

Gouveia, Nuno D., Duarte M. V. Faria, and António Pinho Ramos. "Assessment of SFRC flat slab punching behaviour – part II: reversed horizontal cyclic loading." Magazine of Concrete Research. 71 (2019): 26-42. AbstractWebsite

This paper presents an experimental study of four flat slab specimens subjected to combined vertical and horizontal cyclic loading. Steel fibre-reinforced concrete (SFRC) was used only in the local region of the slab–column connection, while the rest of the slabs were cast using normal concrete. The specimens measured 4·15 m × 1·85 m × 0·15 m and were connected to two steel half columns by 0·25 m × 0·25 m rigid steel plates, prestressed against the slab using steel bolts, to ensure monolithic behaviour. The specimens were tested using an innovative test setup system that accounted for important factors, such as the ability of bending moment redistribution, line of inflection mobility and assured equal vertical displacements at the opposite slab borders, and symmetrical shear forces. Results show that the presence of SFRC in the slab–column connection region is effective in increasing the deformation capacity of slab–column connections, allowing the increase of horizontal drift ratios.

Torabian, Ala, Brisid Isufi, Davood Mostofinejad, and António Pinho Ramos. "Behavior of thin lightly reinforced flat slabs under concentric loading." Engineering Structures. 196 (2019): 109327. AbstractWebsite

The current research aims to study the behavior of thin reinforced concrete (RC) slabs under concentrated loads as well as to investigate the application of Critical Shear Crack Theory (CSCT) to such slabs. For this purpose, four square 100-mm-thick slabs were cast and subjected to concentrated punching monotonic loading. The experimental parameters were the flexural reinforcement ratio, 0.38% and 1.00%, and the presence or absence of shear headed stud reinforcement. It is shown that the failure criteria of CSCT describe reasonably well the observed failure modes and the ultimate loads of the specimens. However, attention is brought to some peculiarities in the analytical derivation of the load-rotation curve for thin lightly reinforced flat slabs, in which large deformations are experienced. Results showed that in such slabs, the behavior can be highly influenced by the post-yield stress-strain curve of the flexural steel reinforcement. As a result, the constitutive law of steel reinforcement should be explicitly taken into account in such cases. The versatility of CSCT to adapt to these conditions is demonstrated.

Yang, Y., M. A. G. Silva, H. Biscaia, and C. Chastre. "Bond durability of CFRP laminates-to-steel joints subjected to freeze-thaw." Composite Structures. 212 (2019): 243-258. AbstractWebsite

The degradation mechanisms of bonded joints between CFRP laminates and steel substrates under severe environmental conditions require more durability data and studies to increase the database and better understand their causes. Studies on bond properties of double-strap CFRP-to-steel bonded joints with two different composite materials as well as adhesive coupons subjected to freeze-thaw cycles for 10,000 h were conducted to reduce that gap. In addition, the equivalent to the number of thermal cycles and their slips induced in the CFRP laminates was replicated by an equivalent (mechanical) loading-unloading history condition imposed by a static tensile machine. The mechanical properties of the adhesive coupons and the strength capacity of the bonded joints were only slightly changed by the artificial aging. It was confirmed that the interfacial bond strength between CFRP and adhesive is critically related to the maximum shear stress and failure mode. The interfacial bond strength between adhesive and steel degraded with the aging. However, the equivalent thermal cyclic bond stress caused no detectable damage on the bond because only the interfacial elastic regime was actually mobilized, which confirmed that pure thermal cycles aging, per se, at the level imposed, have a low impact on the degradation of CFRP-to-steel bonded joints. © 2019 Elsevier Ltd

Teubig, P., P. Remmels, P. Klenze, H. Alvarez-Pol, E. Alves, J. M. Boillos, P. Cabanelas, R. C. da Silva, D. Cortina-Gil, J. Cruz, D. Ferreira, M. Fonseca, D. Galaviz, E. Galiana, R. Gernhäuser, D. González, A. Henriques, A. P. Jesus, H. Luís, J. Machado, L. Peralta, J. Rocha, A. M. Sánchez-Benítez, H. Silva, and P. Velho. "Challenging the Calorimeter CALIFA for FAIR Using High Energetic Photons." Eds. José-Enrique García-Ramos, María V. Andrés, José Lay A. Valera, Antonio M. Moro, and Francisco Pérez-Bernal. Cham: Basic Concepts in Nuclear Physics: Theory, Experiments and Applications, 2019. 245-246. Abstract
n/a
Carl, C., P. Lopes, M. Sá da Costa, G. Canon Falla, S. Leischner, and R. Micaelo. "Comparative study of the effect of long-term ageing on the behaviour of bitumen and mastics with mineral fillers." Construction and Building Materials. 225 (2019): 76-89. AbstractWebsite

This study aims to evaluate the effect of mineral fillers on bitumen ageing. Two different bitumens and four mastics were investigated in the unaged and long-term aged states, based on different properties (consistency, rheology, fatigue resistance and ductility). Mastics stiffened less due to ageing treatment than bitumens, especially with granite filler. However, the results of the performance tests were not definitive regarding the effect of the filler. Aged bitumen showed greater fatigue resistance and higher specific energy of ductile fracture than unaged bitumen, whereas the mastics showed minor variations in the specific energy of ductile fracture with ageing treatment, which is indicative of less ageing, but the fatigue resistance decreased significantly in mastics with one of the bitumens.

Al-Saadi, M., S. Valtchev, L. Romba, J. Gon?alves, and A. Cr?ciunescu. "Comparison of Spiral and Square Coil Configurations in Wireless Power Transfer System for Contactless Battery Charging." 2019 Electric Vehicles International Conference, EV 2019 (2019). Abstract
n/a
Araújo, João, Michael Kinyon, and Janusz Konieczny. "Conjugacy in inverse semigroups." J. Algebra. 533 (2019): 142-173. AbstractWebsite
n/a
Valtchev, Stan, and Svilen Valtchev. "Control for the Contactless Series Resonant Energy Converter." Emerging Capabilities and Applications of Wireless Power Transfer. IGI Global, 2019. 102-140. Abstract

This chapter presents control methods applied in the operation of the series loaded series resonant (SLSR) power converters in a most efficient operation zone. The choice of the control method is affected by the objective to guarantee suitably the efficiency, being this method in the same time, relatively easy to apply. The first part of the chapter compares three basic principles of regulation: frequency mode (FM), pulse width mode (PWM), and their combination (PWM/FM). Finally, a new method for instantaneous regulation is developed. The proposed technique consists of a simplified observation of a state variable value to limit each portion of supplied energy, depending on the requirement for power in each half period. The result of this regulation is comparable to the current mode (CM) control applied to the hard-switching power converters. The viability of this new regulation method is demonstrated by simulations of its analogue circuit implementations and experimentally proved. The circuit is also prepared for the changes in the magnetic coupling (contactless energy transfer).

Azanza, Moreno M., R. Coimbra, E. Puértolas-Pascual, J. Russo, B. Bauluz, and O. Mateus Crystallography of Lourinhanosaurus eggshells (Dinosauria, Theropoda, Allosauroidea). Journal of Vertebrate Paleontology, Program and Abstracts., 2019. Abstract
n/a
Biscaia, H. C., R. Micaelo, and C. Chastre. "Cyclic performance of adhesively bonded joints using the Distinct Element Method: Damage and parametric analysis." Composites Part B: Engineering. 178 (2019). AbstractWebsite

Adhesively bonded joints have been widely used by engineers to solve problems in different industries. Despite recent studies which have helped with the design and application of these joints, there are still several uncertainties that justify empirical implementation in practice. One main aspect is the rigorous understanding of the performance of these joints when subjected to cyclic loading. Although the monotonic performance of adhesively bonded joints is well known, the cyclic behaviour raises several issues. Therefore, a numerical strategy based on the Distinct Element Method (DEM) was implemented in this work to mitigate the lack of knowledge about the cyclic behaviour between two materials adhesively bonded to each other. For that purpose, the single-lap pull-push test was modelled and due to the diversity of the existing cohesive models, four different bond-slip relationships and two unloading paths (with ductile or “cleavage unloading”) were considered. The results suggest that if the bond-slip relationship has an elastic stage, then the interfacial bond degradation is delayed. On the other hand, the interfacial damage of the joints with the number of cycles increases rapidly in those cases where the bond-slip relationships have no elastic stage and, at the same time, the slip accumulation is allowed. In addition, the results of two different tests available in the literature were implemented and fairly reproduced by the DEM. © 2019 Elsevier Ltd

Cidade, Rafael A., Daniel S. V. Castro, Enrique M. Castrodeza, Peter Kuhn, Giuseppe Catalanotti, Jose Xavier, and Pedro P. Camanho. "Determination of mode I dynamic fracture toughness of IM7-8552 composites by digital image correlation and machine learning." Composite Structures. 210 (2019): 707-714. AbstractWebsite

An optical experimental procedure for evaluating the J-Integral from full-field displacement fields under dynamic loading is proposed in this work. The methodology is applied to measure the J-integral in the dynamic compressive loading of fiber-reinforced composites and to calculate the dynamic fracture toughness associated with the propagation of a kink-band. A modified J-Integral that considers inertia effects is calculated over the full-field measurements obtained by digital image correlation, for double edge-notched specimen of IM7-8552 laminates dynamically loaded in a split-Hopkinson pressure bar (SHPB). A sensibility study is conducted to address the influence of the speckle parameters. The results show good agreement with experimental observations obtained by using a different data reduction method, suggesting the existence of a rising R-curve for the studied material under dynamic loading. Furthermore, it was noticed that the inertia effect can be negligible, indicating a state of dynamic equilibrium in which quasi-static approaches may comfortably be used.