Wind loads analysis at the anchorages of the Talavera de la Reina cable stayed bridge

This paper describes wind tunnel tests performed on wind tunnel models of the Talavera de la Reina cable stayed bridge. The work describes the aeroelastic model construction and it is focused on the evaluation and analysis of the mean and peak wind loads at the tower foundation and the cable anchorages since these data can be very useful by the bridge manufacturer as a support for the bridge design. The work is part of a complete wind tunnel study carried out to analyze the aeroelastic stability of the bridge

Mechanisms for analysis and detection of ransomware in desktop operating systems

Mestrado de dupla diplomação com a UTFPR - Universidade Tecnológica Federal do ParanáRansomware attacks have become a danger to computer systems, leading to data loss, monetary losses, and business interruptions. We propose a machine learning-based method for ransomware detection on Linux to identify these attacks. To detect ransomware activity on the system, our approach combines the file system with a predictive model. To obtain sufficient infection information we use the data from the alteration calls to the files on the file system. This data is then fed into a machine-learning algorithm. Using a dataset we collected from uninfected files and files infected with various types of ransomware and were able to achieve a high detection rate with a low false positive rate. Our methodology can be incorporated into current security programs to improve detection and defense against ransomware attacks in the Linux environment.Os ataques de ransomware se tornaram um perigo para os sistemas de computador, levando à perda de dados, perdas monetárias e interrupções nos negócios. Propomos um método baseado em aprendizado de máquina para detecção de ransomware no Linux para identificar esses ataques. Para detectar a atividade de ransomware no sistema, nossa abordagem combina o sistema de arquivos com um modelo preditivo. Para obter informações suficientes sobre a infecção, usamos os dados das chamadas de alteração dos arquivos no sistema de arquivos. Esses dados são então inseridos em um algoritmo de aprendizado de máquina. Usando um conjunto de dados que coletamos de arquivos não infectados e arquivos infectados com vários tipos de ransomware, conseguimos atingir uma alta taxa de detecção com uma baixa taxa de falsos positivos. Esta metodologia pode ser incorporada nos programas de segurança atuais para melhorar a detecção e a defesa contra ataques de ransomware no ambiente Linux

Full scale monitoring of the twin chimneys of the rovinari power plant

The presented paper deals with the structural identification and monitoring of two twin chimneys in very close arrangement. Due to twin arrangement, important interference effects are expected to modify the chimney response to wind action, causing vortex shedding and state-dependent excitation associated to the oscillatory motion of the leeward chimney, in and out of the windward chimney wake. The complexity of the physics of this problem is increased by the dependency of the aerodynamics of circular cylinders on Reynolds number; however, there is a weakness of literature about cylinders behaviour at critical and super-critical range of Reynolds number, due to experimental limitations. Also the International Committee on Industrial Chimneys (CICIND) does not provide, at present, any specific technical guideline about twin chimneys whose interaxis distance is less or equal two times the diameter, as in this case. For this reason a Tuned Mass Damper (TMD) has been installed in order to increase the damping of the chimney, as merely suggested. This work aims at assessing the effectiveness of the installed TMD and characterizing the tower dynamic behaviour itself due to the wind excitation, as well as providing full scale measurements for twin cylinders configuration at high Reynolds numbers

Wind tunnel validation of AeroDyn within LIFES50+ project: Imposed Surge and Pitch tests

This paper presents the first set of results of the steady and unsteady wind tunnel tests, performed at Politecnico di Milano wind tunnel, on a 1/75 rigid scale model of the DTU 10 MW wind turbine, within the LIFES50+ project. The aim of these tests is the validation of the open source code AeroDyn developed at NREL. Numerical and experimental steady results are compared in terms of thrust and torque coefficients, showing good agreement, as well as for unsteady measurements gathered with a 2 degree-of-freedom test rig, capable of imposing the displacements at the base of the model, and providing the surge and pitch motion of the floating offshore wind turbine (FOWT) scale model. The measurements of the unsteady test configuration are compared with AeroDyn/Dynin module results, implementing the generalized dynamic wake (GDW) model. Numerical and experimental comparison showed similar behaviours in terms of non linear hysteresis, however some discrepancies are herein reported and need further data analysis and interpretations about the aerodynamic integral quantities, with a special attention to the physics of the unsteady phenomenon

Aerodynamic design methodology for wind tunnel tests of wind turbine rotors

This paper illustrates the methodology and the experimental verification of the design of a 1/75 aero-elastic scaled rotor of the DTU 10 MW reference wind turbine for wind tunnel tests. The aerodynamic design was focused on the minimization of the difference, in terms of thrust coefficient, with respect to the full scale reference. From the Selig low-Reynolds airfoils database, the SD7032 one was chosen for this purpose and a corresponding constant section wing was tested at DTU red wind tunnel, providing force and distributed pressure coefficients for the design, in the Reynolds range 30−250×103 and for different angles of attack. The aero-elastic design algorithm was set to define the optimal spanwise thickness over chord ratio (t/c), the chord length and the twist, in order to match at least the first flapwise scaled natural frequency. An aluminium mould for the carbon fibre autoclave process was CNC manufactured based on B-Splines CAD definition of the external geometry given as an output of the design procedure. Wind tunnel tests at were carried out Politecnico di Milano on the whole 1/75 wind turbine scale model, confirming the successful aerodynamic design and manufacturing approaches. The experimental modal analysis carried out to verify the structural consistency of the scaled blade is also reported