L.R. Padovese

L.R. Padovese
University of São Paulo | USP

Doctor of Engineering

About

128
Publications
20,664
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1,354
Citations
Citations since 2017
37 Research Items
741 Citations
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2017201820192020202120222023020406080100120140
2017201820192020202120222023020406080100120140
2017201820192020202120222023020406080100120140

Publications

Publications (128)
Preprint
Full-text available
The maned wolf (Chrysocyon brachyurus; Illiger, 1815) is considered the largest canid in South America, it has crepuscular nocturnal behavior, solitary and skittish habits. Its vocalization has different classifications, one of them called roar-barks, which helps in long-distance communication, being ideal for passive acoustic monitoring. For the s...
Article
The study of the acoustic emission of underwater gas bubbles is a subject of both theoretical and applied interest, since it finds an important application in the development of acoustic monitoring tools for detection and quantification of underwater gas leakages. An underlying physical model is essential in the study of such emissions, but is not...
Preprint
Full-text available
The study of the acoustic emission of underwater gas bubbles is a subject of both theoretical and applied interest, since it finds an important application in the development of acoustic monitoring tools for detection and quantification of underwater gas leakages. An underlying physical model is essential in the study of such emissions, but is not...
Preprint
Full-text available
Avian survey is a time-consuming and challenging task, often being conducted in remote and sometimes inhospitable locations. In this context, the development of automated acoustic landscape monitoring systems for bird survey is essential. We conducted a comparative study between two machine learning methods for the detection and identification of 2...
Poster
Full-text available
The humpback whales from the breeding stock A are recovering and currently, the whales are observed throughout northeastern Brazil. Since 2014, monitoring studies of humpbacks have begun in Serra Grande, a region where the continental shelf is narrower in the Brazilian coast, allowing the whales to approach near the coast. Land-based visual monitor...
Poster
Full-text available
South America hosts two stocks of humpback whales (Megaptera novaeangliae), stock A occupying southwest waters of the Atlantic, and stock G, located in the Southeast Pacific. After breeding in these locations in the austral winter and spring, both stocks travel in the austral summer to the feeding areas located in the Magellan Strait, Corcovado Gul...
Article
An algorithm for detecting tonal vocalizations from estuarine dolphin (Sotalia guianensis) specimens without interference of a human operator was developed. The raw audio data collected from a passive monitoring sensor in the Cananéia underwater soundscape was converted to spectrogram images. Detection is a four-step method: first, ridge maps are o...
Conference Paper
The sound emitted by a bubble of gas dissolved in a fluid medium is a phenomenon that has been studied since the late nineteenth century. In order to identify the frequency spectrum of this type of acoustic emission, different mathematical models have been proposed since then. In the present article, preliminary results of the computational simulat...
Conference Paper
Cuando los materiales ferromagnéticos son sometidos a campos magnéticos variables, el cambio en la inducción magnética ocurre de manera discontinua como resultado del movimiento de las paredes de los dominios magnéticos. Esos saltos discretos producen señales conocidas como Ruido Magnético Barkhausen (RMB). El RMB es sensible a las alteraciones mic...
Preprint
An algorithm for detecting tonal vocalizations from estuarine dolphin (Sotalia guianensis) specimens without interference of a human operator is developed. The raw audio data collected from a passive monitoring sensor in the Canan\'eia underwater soundscape is converted to spectrogram images, containing the desired acoustic event (whistle) as a lin...
Article
Full-text available
Changepoint analysis (also known as segmentation analysis) aims to analyze an ordered, one-dimensional vector in order to find locations where some characteristic of the data changes. Many models and algorithms have been studied under this theme, including models for changes in mean and/or variance, changes in linear regression parameters, etc. Thi...
Article
Sound emissions by ships and boats can strongly impact marine life, with potential to affect communications, breeding and prey and predator relationships. Automatic detection of boat signatures in underwater audio recordings is thus an important task. Automated solutions are particularly relevant for monitoring preservation areas where the presence...
Preprint
Full-text available
Underwater gas reservoirs are used in many situations. In particular, Carbon Capture and Storage (CCS) facilities that are currently being developed intend to store greenhouse gases inside geological formations in the deep sea. In these formations, however, the gas might percolate, leaking back to the water and eventually to the atmosphere. The ear...
Preprint
Full-text available
Changepoint analysis (also known as segmentation analysis) aims at analyzing an ordered, one-dimensional vector, in order to find locations where some characteristic of the data changes. Many models and algorithms have been studied under this theme, including models for changes in mean and / or variance, changes in linear regression parameters, etc...
Article
Full-text available
This work studies the application of a Non-Destructive Inspection Technique (NDIT), based on the Magnetic Barkhausen Noise (MBN), for the detection of non-homogeneous regions in carbon steel plates. It presents the advances in the development of a variant of a new non-destructive magnetic test technique, called Continuous Scanning Magnetic Barkhaus...
Article
Hydroelectric power plants (HPP) constitute one of the main forms of energy generation in the world, and its operation produces underwater noise through generators and turbines, which can potentially impact the aquatic fauna. Anthropogenic noise is a stressful factor and can affect behaviour, physiology and acoustic communication of many animal spe...
Poster
Full-text available
Humpback whales migrate to the Brazilian coast during the austral winter to reproduce and calve. Males sing long complex songs with repetitive patterns, and each population has its own song version that changes over time. The objectives of this study were: 1) to define the song structure in 2014 and 2015 in the Brazilian breeding area; 2) to analyz...
Poster
Full-text available
Acoustic communication plays an important role for whales due to the propagation efficiency of sounds over long distances in the marine environment. While humpback whales’ song is emitted only by males mainly during the breeding season, social sounds (calls or sounds produced on the surface of water through aerial behaviors) are produced by both ma...
Article
Full-text available
Durante el proceso de magnetización de un material ferromagnético, las paredes de los dominios magnéticos son forzadas a moverse bajo la influencia del campo magnético. Para que las paredes se puedan mover deben superar la resistencia producida por los puntos de anclaje (borde de grano, dislocaciones, inclusiones, etc.), ocasionando saltos discreto...
Chapter
Full-text available
The problem of detecting a signal of known form in a noisy message is a long-studied problem. In this paper, we formulate it as the test of a sharp hypothesis, and propose the Full Bayesian significance test of Pereira and Stern as the tool for the job. We study the FBST in the signal detection problem using simulated data, and also using data from...
Article
Full-text available
This paper reports the use of a non-destructive scanning technique to identify plastic deformation defects generated in steel. The technique is based on measurement of continuous magnetic Barkhausen noise (CMBN). In the experiments described here, surfaces with plastic deformations produced by crushing stresses in a 1070 steel are scanned, and the...
Article
Full-text available
In a recent paper, we have proposed an unsupervised algorithm for audio signal segmentation entirely based on Bayesian methods. In its first implementation, however, the method showed poor computational performance. In this paper we address this question by describing a fast parallel implementation using the Cython library for Python; we use open G...
Article
Full-text available
The problem of event detection in general noisy signals arises in many applications; usually, either a functional form of the event is available, or a previous annotated sample with instances of the event that can be used to train a classification algorithm. There are situations, however, where neither functional forms nor annotated samples are ava...
Preprint
Full-text available
The problem of event detection in general noisy signals arises in many applications; usually, either a functional form for the event is available, or a previous annotated sample with instances of the event that can be used to train a classification algorithm. There are situations, however, where neither functional forms nor annotated samples are av...
Preprint
Full-text available
The problem of event detection in general noisy signals arises in many applications; usually, either a functional form for the event is available, or a previous annotated sample with instances of the event that can be used to train a classification algorithm. There are situations, however, where neither functional forms nor annotated samples are av...
Preprint
Full-text available
The problem of event detection in general noisy signals arises in many applications; usually, either a functional form for the event is available, or a previous annotated sample with instances of the event that can be used to train a classification algorithm. There are situations, however, where neither functional forms nor annotated samples are av...
Article
Full-text available
The magnetic Barkhausen emission is investigated in deformed ANSI 1050 steel samples using four experimental configurations. These configurations vary according the type of magnetization (solenoid or yoke) and the recording the magnetic signal (bobbin above or around sample).The level of total strain was 0.4, 0.8, 1.0 and 3.0%. In all cases the sam...
Article
This paper reports the use of a non-destructive continuous magnetic Barkhausen noise technique to detect applied stress on steel surfaces. The stress profile generated in a sample of 1070 steel subjected to a three-point bending test is analyzed. The influence of different parameters such as pickup coil type, scanner speed, applied magnetic field a...
Conference Paper
Full-text available
THE INFLUENCE OF PEARLITE LAMELLAR DISTANCE ON HARDNESS, MAGNETIC SATURATION AND MAGNETIC BARKHAUSEN NOISE Abstract Research about rail transport in Brazil has been intensified recently due the need to improve the wheel-rail performance, considering the demand of increasing axle load aiming for a transportation cost reduction. Changes in the materi...
Presentation
Full-text available
Humpback whales use the Brazilian coast to breed and calve. The number of individuals of the population from reproductive stock A has increased in the past few years. Whales are reoccupying areas used before being affected by whaling, lacking detailed information about their presence along the coast. Thereby, the objective of this study was to desc...
Article
Long-term passive acoustic monitoring can provide important insights on the study of biological choruses, which represent a key component of natural environments. Nowadays, the development of methods for analysis and visualization of large acoustic datasets is an active area of research. In this context, the present paper addresses how the traditio...
Article
The Laje de Santos Marine State Park (LSMSP) and Xixová-Japuí State Park (XJSP) are two protected areas (PAs) located in the southern Atlantic Brazilian coast. One month of continuous underwater sound recordings allowed determining that durable fish choruses was a major contributor of LSMSP and XJSP soundscapes. The choruses showed well defined dai...
Article
Full-text available
Duplex stainless steels have a structure normally composed of austenite and ferrite in approximately equal proportions. In order to attain control of its fabrication processes and performance, it is important to understand its microstructural evolution, due to the formation of intermetallic phases such as sigma (σ) and chi (χ), which may cause a se...
Article
Residual stresses typically are generated during the manufacturing process of mechanical components. The non-destructive techniques are quite sensitive to these residual stresses, and to microstructural changes resulting from thermal cycling. In this work, samples of API 5L X80 steel were exposed to several conditions of cooling, under water, air a...
Article
The use of structural steel in the industry is increasing every day, and the study of stress state after welding has been shown to be of great importance. Nondestructive techniques become quite appropriate to be performed before and during the service component of welded, and thus ensure its integrity. The magnetic technique to be nondestructive, a...
Presentation
Full-text available
Humpback whales (Megaptera novaeangliae) migrate to the Brazilian coast during the winter and spring to breed and calve. During this time, the males sing complex songs related to mating. Although most of the studies on acoustic communication of the species are focused on song, humpback whales also use other “social sounds” to communicate. Non-song...
Article
Full-text available
The movement of magnetic domain walls can be disturbed by material defects, also named pinning sites. When the magnetic field is changing, the domain walls move by “jumps” over these pinning sites. These jumps produce the so named magnetic Barkhausen noise (MBN). During walls movements also low amplitude and high frequency elastic waves are generat...
Article
Full-text available
When a slowly variable magnetic field (∼ Hz) is applied through a yoke on a ferromagnetic material, discontinuous changes on the magnetic flow density are produced. This phenomenon, called Magnetic Barkhausen Noise (MBN), obeys the movement of magnetic domain walls and its frequency range is about [10–100] kHz. It involves sudden magnetization chan...
Article
Full-text available
When a variable magnetic field is applied to a ferromagnetic material, it has been observed that, next to the coercive field (Hc), rise in induction (B) takes place through abrupt jumps known as Barkhausen jumps. In this research, the microstructure variation in carbon steel welded joints was monitored by the Magnetic Barkhausen Noise (MBN). The sa...
Conference Paper
Sound propagation in shallow waters can have great variability due to many different characteristics of these environments and its described by numerous interactions with both the sea surface and sea floor which influence the propagation of acoustic energy through reflection, scattering and absorption. Here we used the basic spreading loss acoustic...
Conference Paper
Summation of energy, commonly known as Energy Detectors, is a class of signal processing methods that can be used to detect underwater acoustic events in the recorded signal data. The key in Energy Detectors is the construction of a Detection Function that can differentiate the acoustic event from the background. In this work, we evaluate the perfo...
Article
Full-text available
As industrial activities continue to grow on the Brazilian coast, underwater sound measurements are becoming of great scientific importance as they are essential to evaluate the impact of these activities on local ecosystems. In this context, the use of commercial underwater recorders is not always the most feasible alternative, due to their high c...
Article
It is well known that rising anthropogenic underwater noise has chronic impacts on marine fauna. Since the contribution of navigation is particularly important to this kind of noise, areas near big harbors can be critically affected. One case of great environmental concern is the Port of Santos, the largest harbor in Latin America that, additionall...
Article
Full-text available
A pesquisa de vazamentos não visíveis por métodos acústicos em sistemas de abastecimento de água é dependente do treinamento, da experiência e da capacidade auditiva dos técnicos. Contudo, os sinais acústicos emitidos pelos vazamentos e transmitidos à superfície dos pavimentos possuem características espectrais que podem ser utilizadas para identif...
Article
Full-text available
Three steels with similar microstructure but with very different mechanical properties were examined with nondestructive technique magnetic Barkhausen noise (MBN). All these steels were submitted to a very small plastic deformation (tensile test), varying between 0.5% and 4% of deformation. It was found that 180 $^{circ}$ domain wall movement becom...
Article
Full-text available
he nondestructive Magnetic Barkhausen Noise (MBN) technique was applied for the evaluation of SAE 4140 and SAE 6150 steels after a Jominy end-quench test. Microstructures were also characterized by SEM (Scanning Electron Microscope) and hardness tests. MBN measurements were performed on the same sample regions at three excitation frequencies. Diffe...
Article
This work proposes a system for classification of industrial steel pieces by means of magnetic nondestructive device. The proposed classification system presents two main stages, online system stage and off-line system stage. In online stage, the system classifies inputs and saves misclassification information in order to perform posterior analyses...
Article
Risers are flexible multilayered pipes formed by an inner flexible metal structure surrounded by polymer layers and spiral wound steel ligaments, also known as armor wires. Since these risers are used to link subsea pipelines to floating oil and gas production installations, and their failure could produce catastrophic consequences, some methods ha...
Article
Full-text available
Purpose The purpose of this paper is to provide information on lubricant contamination by biodiesel using vibration and neural network. Design/methodology/approach The possible contamination of lubricants is verified by analyzing the vibration and neural network of a bench test under determinated conditions. Findings Results have shown that class...
Article
Full-text available
The Magnetic Barkhausen Noise (MBN) technique can evaluate both micro- and macro-residual stresses, and provides indication about the relevance of contribution of these different stress components. MBN measurements were performed in AISI 1070 steel sheet samples, where different strains were applied. The Barkhausen emission is also analyzed when tw...
Article
The magnetic behaviour of most commercial ferromagnetic steels is usually anisotropic presenting a magnetic easy axis. Changes in the direction of this axis can be related to mechanical changes and anomalies that occur in the fabrication process. The present work describes a method that uses a device with permanent magnets to create a precise rotat...
Article
Full-text available
The use of Magnetic Barkhausen Noise (MBN) as a experimental method for measuring the martensite start (Ms) temperature was explored, using as model system a cold-work tool steel (AISI D2) austenitized at a very high temperature (1473 K), so as to transform in sub-zero temperatures. The progress of the transformation was also followed with electric...
Article
Experiments exploring the Magnetic Barkhausen Noise (MBN) during the martensitic transformation led to the discovery of a novel phenomenon, here called "Spontaneous magnetic emission" (SME). This new phenomenon was identified while testing the hypothesis that there would be a Barkhausen Noise-like magnetic emission as a consequence ofthe_movementof...
Article
Flexible risers are used to link subsea pipelines to oil and gas production floating installations. These risers are multilayered pipes formed by an inner flexible metal carcass surrounded by polymer layers and spiral wound steel ligaments, also known as armor wires. In this riser, the armor wires sometimes break during installation or due to mecha...
Article
Full-text available
One of the goals of the steel-based industrial applications is the detection of the mechanical stress state of steel structures. The mechanical tensile stress modifies the magnetic anisotropy in ferromagnetic materials. This fact can be used to detect changes in the stress state of the material using magnetic inspection methods. The Magnetic Barkha...
Article
Full-text available
Magnetic Barkhausen noise (MBN) was used to characterize the progress of austenite to martensite phase transformation while cooling steel specimens, using a conventional Barkhausen noise emission setup stimulated by an alternating magnetic field. The phase transformation was also followed by electrical resistivity measurements and by optical and sc...
Article
This work presents a Feature Selection Algorithm for optimization of a Probabilistic Neural Network. The aim of this Probabilistic Neural Network is classifying signals obtained from magnetic material samples where two micro-structural parameters were changed simultaneously. The combination of the Feature Selection Algorithm with the Probabilistic...
Article
Full-text available
Grain oriented electrical steels present strong anisotropy, due to a {110} <001> texture (Goss), with [100] direction parallel to rolling direction (RD) and [110] direction parallel to transverse direction (TD). MBN (Magnetic Barkhausen Noise) were employed to measure magnetic properties in several angles towards RD using a 15° step. For 90° to the...
Article
Full-text available
Steels with different carbon content, 0.11%C and 0.48%C were submitted to a heat treatment for carburization in the surface. The samples were analyzed after several types of heat treatment, including quenching for producing martensite. The Magnetic Barkhausen Noise (MBN) is directly related to the microstructure. Samples with lower carbon content,...
Article
Full-text available
The use of magnetic Barkhausen (MBN) noise methods to detect the austenite to martensite phase transformation during cooling of steel specimens was explored, using three different configurations: conventional Barkhausen noise emission stimulated by an alternating magnetic field, the Okamura method, that measures magnetic noise emission under a fixe...
Article
Full-text available
The effects of low temperature isothermal treatments on a quenched AISI D2 tool steel was studied using Barkhausen Noise, X-ray diffraction, dilatometry and optical and electronic microscopy. The specimens were austenitized at 1040 degrees C and quenched in oil. The isothermal treatments involved immersion in hot oil baths at 80 degrees or 130 degr...
Article
In this work, an algorithm to compute the envelope of non-destructive testing (NDT) signals is proposed. This method allows increasing the speed and reducing the memory in extensive data processing. Also, this procedure presents advantage of preserving the data information for physical modeling applications of time-dependent measurements. The algor...
Article
Full-text available
This work studies the influence of machining parameters, such as cutting speed and forces, feed rate, cutting depth, and tool flank wear, on the generation of surface residual stresses in DIN 100Cr6 steel conical bearing rings submitted to a hard turning process. A complete factorial planning was used to perform the tests and projected measurement....