Autonomous Sensor System for Low-Capacity Wind Turbine Blade Vibration Measurement.

This paper presents the design, implementation, and validation of an on-blade sensor system for remote vibration measurement for low-capacity wind turbines. The autonomous sensor system was deployed on three wind turbines, with one of them operating in harsh weather conditions in the far south of Chile. The system recorded the acceleration response of the blades in the flapwise and edgewise directions, data that could be used for extracting the dynamic characteristics of the blades, information useful for damage diagnosis and prognosis. The proposed sensor system demonstrated reliable data acquisition and transmission from wind turbines in remote locations, proving the ability to create a fully autonomous system capable of recording data for monitoring and evaluating the state of health of wind turbine blades for extended periods without human intervention. The data collected by the sensor system presented in this study can serve as a foundation for developing vibration-based strategies for real-time structural health monitoring.

A Review of Automation and Sensors: Parameter Control of Thermal Treatments for Electrical Power Generation.

This review delves into the critical role of automation and sensor technologies in optimizing parameters for thermal treatments within electrical power generation. The demand for efficient and sustainable power generation has led to a significant reliance on thermal treatments in power plants. However, ensuring precise control over these treatments remains challenging, necessitating the integration of advanced automation and sensor systems. This paper evaluates the pivotal aspects of automation, emphasizing its capacity to streamline operations, enhance safety, and optimize energy efficiency in thermal treatment processes. Additionally, it highlights the indispensable role of sensors in monitoring and regulating crucial parameters, such as temperature, pressure, and flow rates. These sensors enable real-time data acquisition, facilitating immediate adjustments to maintain optimal operating conditions and prevent system failures. It explores the recent technological advancements, including machine learning algorithms and IoT integration, which have revolutionized automation and sensor capabilities in thermal treatment control. Incorporating these innovations has significantly improved the precision and adaptability of control systems, resulting in heightened performance and reduced environmental impact. This review underscores the imperative nature of automation and sensor technologies in thermal treatments for electrical power generation, emphasizing their pivotal role in enhancing operational efficiency, ensuring reliability, and advancing sustainability in power generation processes.

Monitoring multiple parameters in complex water scenarios using a low-cost open-source data acquisition platform.

Water monitoring faces challenges that are driven by the infrastructure, protection, financial resources, science and innovation policies, among others. A modular, low-cost, fully open-source and small-sized Unmanned Surface Vessel (USV) called EMAC-USV (EMAC: Estación de Monitoreo Ambiental Costero), is proposed for monitoring bathymetry and water quality parameters (i.e. temperature, suspended solids concentration and hydrocarbon concentration) in complex water scenarios. A detailed description of each part of the platform as well as all electronic connections and functioning is presented.The field works were carried out in two small waste stabilization ponds and in a portion of the main tidal channel of the Bahía Blanca port. The EMAC-USV is the result of a cautious design, regarding the balancing performance, communications, payload capacity, among others.

Design, Development and Testing of a Monitoring System for the Study of Proton Exchange Fuel Cells and Stacks.

This article is about the design, development and validation of a new monitoring architecture for individual cells and stacks to facilitate the study of proton exchange fuel cells. The system consists of four main elements: input signals, signal processing boards, analogue-to-digital converters (ADCs) and a master terminal unit (MTU). The latter integrates a high-level graphic user interface (GUI) software developed by National Instruments LABVIEW, while the ADCs are based on three digital acquisition units (DAQs). Graphs showing the temperature, currents and voltages in individual cells as well as stacks are integrated for ease of reference. The system validation was carried out both in static and dynamic modes of operation using a Ballard Nexa 1.2 kW fuel cell fed by a hydrogen cylinder, with a Prodigit 32612 electronic load at the output. The system was able to measure the voltage distributions of individual cells, and temperatures at different equidistant points of the stack both with and without an external load, validating its use as an indispensable tool for the study and characterization of these systems.

Survey on Intrusion Detection Systems Based on Machine Learning Techniques for the Protection of Critical Infrastructure.

Industrial control systems (ICSs), supervisory control and data acquisition (SCADA) systems, and distributed control systems (DCSs) are fundamental components of critical infrastructure (CI). CI supports the operation of transportation and health systems, electric and thermal plants, and water treatment facilities, among others. These infrastructures are not insulated anymore, and their connection to fourth industrial revolution technologies has expanded the attack surface. Thus, their protection has become a priority for national security. Cyber-attacks have become more sophisticated and criminals are able to surpass conventional security systems; therefore, attack detection has become a challenging area. Defensive technologies such as intrusion detection systems (IDSs) are a fundamental part of security systems to protect CI. IDSs have incorporated machine learning (ML) techniques that can deal with broader kinds of threats. Nevertheless, the detection of zero-day attacks and having technological resources to implement purposed solutions in the real world are concerns for CI operators. This survey aims to provide a compilation of the state of the art of IDSs that have used ML algorithms to protect CI. It also analyzes the security dataset used to train ML models. Finally, it presents some of the most relevant pieces of research on these topics that have been developed in the last five years.

Damage Classification Using Supervised Self-Organizing Maps in Structural Health Monitoring.

Improvements in computing capacity have allowed computers today to execute increasingly complex tasks. One of the main benefits of these improvements is the possibility of developing machine learning algorithms, of which the fields of application are extensive and varied. However, an area in which this type of algorithms acquires an increasing relevance is structural health monitoring (SHM), where inspection strategies and guided wave-based approaches make the evaluation of the structural conditions of an aircraft, vessel or building among others possible, by detecting and classifying existing damages. The use of sensors, data acquisition systems (DAQ) and computation has also allowed these damage detection and classification tasks to be carried out automatically. Despite today's advances, it is still necessary to continue with the development of more robust, reliable, and low-cost structural health monitoring systems. For this reason, this work contemplates three key points: (i) the configuration of a data acquisition system for signal gathering from an an active piezoelectric (PZT) sensor network; (ii) the development of a damage classification methodology based on signal processing techniques (normalization and PCA), from which the models that describe the structural conditions of the plate are built; and (iii) the use of machine learning algorithms, more specifically, three variants of the self-organizing maps called CPANN (counterpropagation artificial neural network), SKN (supervised Kohonen) and XYF (X-Y fused Kohonen). The data obtained allowed one to carry out an experimental validation of the damage classification methodology, to determine the presence of damages in two aluminum plates of different sizes, where masses were added to change the vibrational responses captured by the sensor network and a composite (CFRP) plate with real damages, such as delamination and cracks. This classification methodology allowed one to obtain excellent results by validating the usefulness of the SKN and XYF networks in damage classification tasks, showing overall accuracies of 73.75% and 72.5%, respectively, according to the cross-validation process. These percentages are higher than those obtained in comparison with other neural networks such as: kNN, discriminant analysis, classification trees, partial least square discriminant analysis, and backpropagation neural networks, when the cross-validation process was applied.

A Low-Cost IoT System for Real-Time Monitoring of Climatic Variables and Photovoltaic Generation for Smart Grid Application.

Monitoring and data acquisition are essential to recognize the renewable resources available on-site, evaluate electrical conversion efficiency, detect failures, and optimize electrical production. Commercial monitoring systems for the photovoltaic system are generally expensive and closed for modifications. This work proposes a low-cost real-time internet of things system for micro and mini photovoltaic generation systems that can monitor continuous voltage, continuous current, alternating power, and seven meteorological variables. The proposed system measures all relevant meteorological variables and directly acquires photovoltaic generation data from the plant (not from the inverter). The system is implemented using open software, connects to the internet without cables, stores data locally and in the cloud, and uses the network time protocol to synchronize the devices' clocks. To the best of our knowledge, no work reported in the literature presents these features altogether. Furthermore, experiments carried out with the proposed system showed good effectiveness and reliability. This system enables fog and cloud computing in a photovoltaic system, creating a time series measurements data set, enabling the future use of machine learning to create smart photovoltaic systems.

Sampling Methods for Metocean Data Aiming at Hydrodynamic Modeling of Estuarine and Coastal Areas.

Field observations require adequate metocean data gathering to promote the link between environmental diagnostic and prognostic obtained from modeling techniques. In general, model confidence can be improved by using data which present better quality and by improved parametrizations. This paper discusses and suggests timing routines for data gathering which are enough to describe the hydrodynamic behavior of estuarine and coastal areas. From the environmental diagnostics viewpoint, a sampling procedure is defined to the temporal scales providing data with adequate resolution to describe the natural process without signal aliasing. The proposed sampling procedure was based on the analysis of a data set of tides, currents, waves, water temperature, and meteorological variables observed at several stations along the Brazilian coast. The instrument setup was based mainly on the results of the harmonic analysis of tides. It is shown that the setup of instruments for simultaneous measurements of currents and waves requires special attention particularly in sites that present low currents and the action of waves. A subset of data gathered in shallow bays was used to estimate the surface turbulent stress by using a classical and a slightly modified parametrization for the wind drag coefficient. Under near neutral atmospheric stability conditions and high tide excursion, the surface turbulent stress obtained with the classical and the modified parametrization differed but the current profiles are expected to be only partially affected by wind-induced drift currents.

Sistema de adquisición de datos en tiempo real para un detector modular de neutrones en los experimentos con el RIBRAS / A real time pulse processing Data acquisition for neutron modular detector on RIBRAS experiments

Resumen Con la finalidad de maximizar las posibilidades experimentales en el estudio de los núcleos exóticos utilizando el haz del sistema "Radioactive Ion Beams in Brasil" (RIBRAS), fue desarrollado un sistema modular de detectores centelleantes orgánicos con buena eficiencia y amplio ángulo sólido, conocido como Pared de Neutrones. La detección de los neutrones emitidos en coincidencia con los fragmentos de reacción incrementa las posibilidades experimentales y constituye una de las técnicas más usadas en el campo de la Astrofísica Nuclear. El obsoleto sistema de adquisición de datos de la Pared de Neutrones debe ser remplazado por un sistema basado en módulos del patrón Versa Module Euro Card (VME). El nuevo esquema será definido para incluir el arreglo de detectores de bandas para partículas cargadas y la Pared de Neutrones con el máximo de eficiencia de adquisición, sin tiempo muerto, con selección de datos y sincronización de eventos. Los módulos digitalizadores garantizan tareas como la supresión de ceros y la saturación en la lectura de la señal. Adicionando tarjetas FPGA (field programmable gate array) a la adquisición de datos se garantiza el procesamiento pre y post-algorítmico de los datos.

Abstract In order to potentiate the experiments for studying the exotic nuclei with Brazil Radioactive Ion Beam (RIBRAS), a modular organic scintillation detector (Neutron Wall), with good efficiency and extended solid angle was developed. The detection of neutrons emitted in coincidence with the reaction fragments increases the experimental possibilities and represents one of the most popular techniques in the Nuclear Astrophysics field. The data acquisition system used for the Neutron Wall is obsolete and should be replaced by Versa Module Euro Card Data Acquisition modules. The new scheme will be designed to include the Strip Array and Neutron Wall detectors with maximum readout efficiency, no dead time, data selection and event synchronization. The digitizer modules provide features like zero suppressed readout and overflow suppression. Zero suppression, once enabled, prevents conversion of value, which is lower than user defined threshold. Adding FPGA (field programmable gate array) cards to data acquisition provides pre- and post-algorithmic processing on data.

Alarma gamma para la protección radiológica / A Gamma Alarm system for radiation protection

En el presente trabajo se describe el desarrollo de un instrumento para el monitoreo radiológico identificado como Alarma Gamma (GAMAL01). Estos monitores detectan el incremento de la tasa de conteo de la radiación y emiten una alarma cuando esta magnitud sobrepasa un umbral determinado. El umbral para la emisión de la alarma se fija de manera que esta se produzca cuando se considere que la tasa de conteo de la radiación pueda provocar una exposición inaceptable del personal a las radiaciones, de acuerdo a lo establecido por las normas de seguridad radiológica vigentes en el país. La señal de alarma indica la necesidad de realizar la evacuación del personal del sitio afectado. El instrumento consta de dos secciones: una analógica y otra digital

This paper describes the development of an instrument for radiological monitoring, identified as Gamma Alarm (GAMAL01). The instrument monitors the increment of radiation count rate and produces an alarm signal, when the count rate becomes superior to a fixed threshold value. The threshold is fixed to assure that the signal emission will start when the value of the radiation count rate may cause a non acceptable radiological exposition of the personnel, according to the radiological safety regulations existing in the country. Following the signal the personnel must be evacuated from the affected place. The instrument consists of two sections, an analogical section and a digital one

Sistema de Rehabilitación de Miembro Inferior Interconectado con un Videojuego: Una Potencial Aplicación para Víctimas de Minas Antipersonal / Lower Limb Rehabilitation System Interfaced with a Videogame: A Potential Application for Landmine Victims

Resumen A nivel mundial se registran anualmente alrededor de 3,308 víctimas de minas antipersonal (MAP), de las cuales un 67% corresponde a lesiones de miembros inferiores que requieren rehabilitación. Este artículo presenta un sistema de adquisición de datos para un equipo de rehabilitación de víctimas de MAP, quienes al interactuar con un videojuego de carreras de automóviles realizan la terapia. El sistema permite al terapeuta establecer una velocidad de pedaleo mínima y analizar la fuerza y velocidad del mismo. El desarrollo conceptual incorpora una bicicleta estática comercial, sensores para medir la fuerza de pedaleo, un sensor óptico para medir la velocidad y pulsadores de mando para interactuar con el videojuego. Para evaluar el sistema se caracterizaron y probaron los sensores, y se realizaron encuestas de percepción a 20 fisioterapeutas relacionadas con ergonomía, seguridad y potenciales beneficios del sistema. El 70%, 90% y 80% de los fisioterapeutas valoraron, respectivamente, estas características en un nivel Alto. Adicionalmente, al menos el 85% de ellos están de acuerdo con nueve beneficios potenciales para personas víctimas de MAP, por lo tanto se plantea que el sistema desarrollado puede utilizarse como 'juego serio' para apoyar las terapias de rehabilitación de personas con prótesis por esta causa.

Abstract Worldwide there are approximately 3,308 records of landmine victims during a year. 67% of them suffered injuries which require physical rehabilitation. This paper presents a data acquisition system for landmine victims rehabilitation, interfaced with a videogame, which enables to interact with a racing game. The therapist can set the minimum speed required for the rehabilitation and analyze the forces and speed developed while pedaling. The conceptual development incorporates a commercial static bicycle, sensors to measure the pedaling force, an optic sensor to measure the speed, and command buttons to control the videogame. In order to evaluate the system, the sensors were characterized and tested, and a survey was conducted to 20 physiotherapists in order to evaluate the perception of ergonomics, safety and possible benefits of the data acquisition system for rehabilitation of landmine victims. 70%, 90% and 80% of the physiotherapists, respectively, assessed these characteristics as High level. Moreover, at least 85% of them are agree with nine possible benefits for rehabilitation of landmine explosion victim. Therefore, it is proposed that the data acquisition system can be used as a serious game that supports rehabilitation therapies of people with a prosthesis due to this cause.

Py4Syn: Python for synchrotrons.

In this report, Py4Syn, an open-source Python-based library for data acquisition, device manipulation, scan routines and other helper functions, is presented. Driven by easy-to-use and scalability ideals, Py4Syn offers control system agnostic solution and high customization level for scans and data output, covering distinct techniques and facilities. Here, most of the library functionalities are described, examples of use are shown and ideas for future implementations are presented.

SU-E-T-162: Rapid Assessment of Cyberknife IRIS Variable Collimator Performance Using a Commercial Diode Array.

PURPOSE: To describe an efficient method for verifying the size and centering of the radiation field from the Cyberknife IRIS variable collimator with sub-millimeter accuracy using a general purpose commercially available diode array. METHODS: We present a technique using a conventional diode array (Sun Nuclear Profiler) with the array at an extended distance of 320 cm. The projection of the 4 mm diode spacing back to the 80 cm field definition distance gives an effective spacing of 1 mm, sufficient to confirm proper operation of the IRIS. We describe the data acquisition process and present data comparing the Profiler measurements to scanned measurements for both profile and FWHM analysis and reproducibility of the technique over repeated measurements. RESULTS: Average difference between original water scanner measurements and diode array measurements over the 12 aperture sizes) from 5 mm to 60 mm) were - 0.14 mm (range 0.03 mm to 0.83 mm). Reproducibility and centering measurements had a similar range of accuracy. CONCLUSIONS: A general purpose commercially available diode array can be used to quickly and accurately characterize the field size and centering of the Cyberknife IRIS variable collimator system with sub-millimeter accuracy subsequent to service, software recalibration, software upgrades or associated with routine QA. This technique avoids the time consuming and cumbersome water tank scanning with a diode and the difficulties associated with image based measurements (CR or radiochromic film) that require time consuming and careful calibration and choice of threshold values.

Telemetria na transmissão de dados de desempenho de máquinas agrícolas utilizando tecnologias GSM/GPRS e ZigBee

This paper presents the tests of a telemetry system (T-SADA) to be adapted to the management of agricultural mechanization using a self-propelled combine harvester to harvest soybeans and rice. The system consists of collecting and sending data of a moving point (a farm machine) to a fixed base (a computer server) and makes the integration of two means of transmission and validation of data (providing fault tolerance). The means of data transmission used were the technology of mobile telephony, GSM / GPRS and radio frequency through the Zigbee. The T-SADA is redundant because it has more than one form of transmission, which ensures the transmission of information even if a media is not able to operate correctly at any given time. Priority is given to the transmission GSM / GPRS and leaving the ZigBee as an alternative means, controlled by an engine fault detection. The results were satisfactory ensuring the transmission of data with fault tolerance and redundantly in remote locations and in different relief.

Este trabalho apresenta os testes de um sistema de telemetria (T-SADA) que foi adaptado ao gerenciamento da mecanização agrícola utilizando uma colhedora automotriz autopropelida na colheita de soja e arroz irrigado. O sistema consiste na coleta e envio de dados de um ponto móvel (a máquina agrícola) para uma base fixa (um computador servidor) e faz a integração de dois meios de transmissão e a validação dos dados (propiciando tolerância a falhas). Os meios de transmissão de dados usados foram a tecnologia da telefonia móvel, GSM/GPRS, e rádio-frequência, através do Zigbee. O T-SADA é redundante, pois possui mais de uma forma de transmissão, o que garante o envio das informações mesmo se um dos meios não tiver condições de operar corretamente num determinado momento. É dada prioridade para a transmissão GSM/GPRS e deixando o ZigBee como meio alternativo, controlado por um mecanismo de detecção de falhas. Os resultados alcançados foram satisfatórios, garantindo a transmissão dos dados com tolerância a falhas e de forma redundante em locais remotos e em diferentes relevos.

Telemetria na transmissão de dados de desempenho de máquinas agrícolas utilizando tecnologias GSM/GPRS e ZigBee

This paper presents the tests of a telemetry system (T-SADA) to be adapted to the management of agricultural mechanization using a self-propelled combine harvester to harvest soybeans and rice. The system consists of collecting and sending data of a moving point (a farm machine) to a fixed base (a computer server) and makes the integration of two means of transmission and validation of data (providing fault tolerance). The means of data transmission used were the technology of mobile telephony, GSM / GPRS and radio frequency through the Zigbee. The T-SADA is redundant because it has more than one form of transmission, which ensures the transmission of information even if a media is not able to operate correctly at any given time. Priority is given to the transmission GSM / GPRS and leaving the ZigBee as an alternative means, controlled by an engine fault detection. The results were satisfactory ensuring the transmission of data with fault tolerance and redundantly in remote locations and in different relief.

Este trabalho apresenta os testes de um sistema de telemetria (T-SADA) que foi adaptado ao gerenciamento da mecanização agrícola utilizando uma colhedora automotriz autopropelida na colheita de soja e arroz irrigado. O sistema consiste na coleta e envio de dados de um ponto móvel (a máquina agrícola) para uma base fixa (um computador servidor) e faz a integração de dois meios de transmissão e a validação dos dados (propiciando tolerância a falhas). Os meios de transmissão de dados usados foram a tecnologia da telefonia móvel, GSM/GPRS, e rádio-frequência, através do Zigbee. O T-SADA é redundante, pois possui mais de uma forma de transmissão, o que garante o envio das informações mesmo se um dos meios não tiver condições de operar corretamente num determinado momento. É dada prioridade para a transmissão GSM/GPRS e deixando o ZigBee como meio alternativo, controlado por um mecanismo de detecção de falhas. Os resultados alcançados foram satisfatórios, garantindo a transmissão dos dados com tolerância a falhas e de forma redundante em locais remotos e em diferentes relevos.

A low cost concept for data acquisition systems applied to decentralized renewable energy plants.

The present paper describes experiences of the use of monitoring and data acquisition systems (DAS) and proposes a new concept of a low cost DAS applied to decentralized renewable energy (RE) plants with an USB interface. The use of such systems contributes to disseminate these plants, recognizing in real time local energy resources, monitoring energy conversion efficiency and sending information concerning failures. These aspects are important, mainly for developing countries, where decentralized power plants based on renewable sources are in some cases the best option for supplying electricity to rural areas. Nevertheless, the cost of commercial DAS is still a barrier for a greater dissemination of such systems in developing countries. The proposed USB based DAS presents a new dual clock operation philosophy, in which the acquisition system contains two clock sources for parallel information processing from different communication protocols. To ensure the low cost of the DAS and to promote the dissemination of this technology in developing countries, the proposed data acquisition firmware and the software for USB microcontrollers programming is a free and open source software, executable in the Linux and Windows® operating systems.

Nuevo dosímetro de zona programable para la medición y monitoreo operacional de la radiación gamma externa / A new programmable zone dosimeter for operational monitoring and measurement of external gamma radiation

RESUMEN La detección y la medición de las radiaciones nucleares se han convertido en un importantísimo renglón en la aplicación de los detectores nucleares y específicamente los Geiger-Muller. Los tubos Geiger con una alta sensibilidad de detección, su robusta construcción y un simple circuito adjunto continúan siendo uno de los detectores más usados en todas las áreas de aplicación en la física e investigaciones nucleares. Se presenta un nuevo diseño de instrumento para medir la tasa de dosis externa ambiental de radiación gamma desde 0,05 µSv/h hasta 10 mSv/h. Consta de tres elementos fundamentales: el detector Geiger-Muller, una tarjeta electrónica de adquisición y control y el software de aplicación. El instrumento se comunica a través de una interfase USB con la computadora solo para variar y ajustar los parámetros de la calibración. El software sedesarrolló en lenguaje C utilizando el compilador PICC4.08.

ABSTRACT The detection and measurement of nuclear radiation have turn into an important aspect in the application of nuclear detectors and specifically, the Geiger Muller tubes. Endowed with high detection sensibility, robust construction and a relative simplicity of the associated circuit, the Geiger Tubes are still one of the most widely used detectors in all areas of application in physics and nuclear research. A new design of the instrument enables measurements of the environmental external dose rate of g (gamma) radiation from 0.05 µSv/h to 10 mSv/h. It consists of three elements: Geiger-Muller detector, a data acquisition and control card and the application software. The instrument is connected to the computer through a USB interface only to vary and adjust the calibration parameters. The software was developed in C programming language using the PICC4.08 compiler.

Electronic nose for quality control of Colombian coffee through the detection of defects in "Cup Tests".

Electronic noses (ENs), are used for many applications, but we must emphasize the importance of their application to foodstuffs like coffee. This paper presents a research study about the analysis of Colombian coffee samples for the detection and classification of defects (i.e., using "Cup Tests"), which was conducted at the Almacafé quality control laboratory in Cúcuta, Colombia. The results obtained show that the application of an electronic nose called "A-NOSE", may be used in the coffee industry for the cupping tests. The results show that e-nose technology can be a useful tool for quality control to evaluate the excellence of the Colombian coffee produced by National Federation of Coffee Growers.

Determination of Force Coresponding to Maximal Lactate Steady State in Tethered Swimming.

The main aim of the present investigation was to verify if the aerobic capacity (AC) measured in tethered swimming corresponds to the maximal lactate steady state (MLSS) and its correlation with 30 min and 400m free style swimming. Twenty-five swimmers were submitted to an incremental tethered swimming test (ITS) with an initial load of 20N and increments of 10N each 3min. After each stage of 3min, the athletes had 30s of interval to blood sample collections that were used to measure blood lactate concentrations ([La-]). The ACBI was determined by the abrupt increase in [La-] versus force (F). The points obtained between [La-] versus force (N) were adjusted by an exponential curve model to determine AC corresponding to 3.5mmol.l-1 (AC3.5) and 4.0mmol.l-1 (AC4.0). After these procedures, the swimmers performed maximal efforts of 30min and 400m in free style swimming. We used the distance performed in 30min and the time performed in 400m to calculate the median velocities (i.e. V30 and V400) of these protocols. After one week, in order to measure the MLSS, nine athletes performed three 30-min tethered swimming efforts with intensities of 90, 100, and 110% of ACBI. The ANOVA one-way was used to compare the ACBI, AC3.5 and AC4.0. Correlations between ACs, and between ACs and V30 and V400 (p<0.05) were determined using the Pearson's correlation coefficient. The intensity corresponding to 100% of ACBI was similar to the MLSS. It was observed significant correlations of the aerobic capacities (i.e. ACBI, AC3.5 and AC4.0) with V30 (r>0.91) and V400 (r>0.63). According to our results, it is possible to conclude that the ACBI corresponds to the MLSS, and both the AC - individually determined - and the AC - determined using fixed blood lactate concentrations of 3.5 and 4.0mmol.l-1 - can be used to predict the mean velocity of 30min and 400m in free style swimming. In addition to that, the tethered swimming system can be used for aerobic development in places where official sized swimming pools are not available, such as rehabilitation clinics and health clubs.