Design of a sensor to estimate suspended sediment transport in situ using the measurements of water velocity, suspended sediment concentration and depth.

- The sediment transport plays a major role in every aquatic ecosystem. However, the lack of instruments to monitor this process has been an obstacle to understanding its effects. We present the design of a single sensor built to measure water velocity, suspended sediment concentration and depth in situ, and how to associate the three variables to estimate and analyse sediment transport. During the laboratory calibrations, the developed instrument presented a resolution from 0.001 g/L to 0.1 g/L in the 0-12 g/L range for the measurement of suspended sediment concentration and 0.05 m/s resolution for 0-0.5 m/s range and 0.001 m/s resolution for 0.5-1 m/s range for the measurement of water velocity. The device was deployed for 6 days in an estuarine area with high sediment dynamics to evaluate its performance. During the field experiment, the sensor successfully measured the tidal cycles and consequent change of flow directions, and the suspended sediment concentration in the area. These measurements allowed to estimate water discharge and sediment transport rates during the different phases of tides, and the daily total volume of water and total amount of sediment passing through the estuary.

Design and In Situ Validation of Low-Cost and Easy to Apply Anti-Biofouling Techniques for Oceanographic Continuous Monitoring with Optical Instruments.

Biofouling is the major factor that limits long-term monitoring studies with automated optical instruments. Protection of the sensing areas, surfaces, and structural housing of the sensors must be considered to deliver reliable data without the need for cleaning or maintenance. In this work, we present the design and field validation of different techniques for biofouling protection based on different housing materials, biocides, and transparent coatings. Six optical turbidity probes were built using polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), PLA with copper filament, ABS coated with PDMS, ABS coated with epoxy and ABS assembled with a system for in situ chlorine production. The probes were deployed in the sea for 48 days and their anti-biofouling efficiency was evaluated using the results of the field experiment, visual inspections, and calibration signal loss after the tests. The PLA and ABS were used as samplers without fouling protection. The probe with chlorine production outperformed the other techniques, providing reliable data during the in situ experiment. The copper probe had lower performance but still retarded the biological growth. The techniques based on transparent coatings, epoxy, and PDMS did not prevent biofilm formation and suffered mostly from micro-biofouling.

Development of an automated sensor for in-situ continuous monitoring of streambed sediment height of a waterway.

The sedimentary processes play a major role in every aquatic ecosystem, however, there are few automated options for in-situ monitoring of sediment displacement in the streambed of waterways. We present an automated optical instrument for in-situ continuous monitoring of sediment deposition and erosion of the streambed that requires no calibration. With a production cost of 32€, power consumption of 300 µA in sleep mode, and capacity to monitor the bedform of a waterway, the sensor was developed to evaluate the sediment dynamics of coastal areas with a wide spatial and temporal resolution. The novel device is intended to be buried in the sand and uses 32 infrared channels to monitor the streambed sediment height. For testing purposes, a maximum measuring length of 160 mm and 5 mm resolution was chosen, but these values are scalable. Sensors can be built with different ranges and precision according to the needs of the fieldwork. A laboratory experiment was conducted to demonstrate the working principle of the instrument and its behaviour regarding the turbidity originated by suspended sediment and the settling and deposition of the suspended particles. The device was deployed for 119 days in an estuarine area and was able to detect patterns in the sediment deposition and resuspension during the tidal cycles. Also, abnormal events occurred during the experiment as floods and algae blooms. During these events, the sensor was able to record exceptional erosion and sediment deposition rates. The reported automated instrument can be broadly used in sedimentary studies or management and planning of fluvial and maritime infrastructures to provide real-time information about the changes in the bedform of the watersheds.

Design of a Multipoint Cost-Effective Optical Instrument for Continuous In-Situ Monitoring of Turbidity and Sediment.

A cost-effective optical instrument for continuous in-situ monitoring applications is presented. With a production cost in raw materials of 38 €, a power consumption of 300 A in sleep mode and 100 mA in active mode (5 ms reading), and a capacity to monitor turbidity and sedimentary displacement at eight different depths in the water column, the sensor was developed for sediment monitoring in coastal areas. Due to the extent and dynamics of the processes involved in these areas, observations require a wide spatial and temporal resolution. Each of the eight monitoring nodes uses one infrared backscatter channel, to estimate turbidity and sediment concentration, and one ultraviolet with one infrared transmitted light channels to distinguish organic/inorganic composition of the suspended material load. An in-lab calibration was conducted, using formazine to correlate turbidity with the electronic outputs of the instrument. An analysis of the influence of external light sources and correction techniques were performed. Moreover, an in-lab experiment was conducted to study the behaviour of the sensor-to-sediment transport, wash load and sediment accumulation. The device was deployed, with a water level sensor, in an estuarine area with high sediment dynamics. The monitoring data were analysed, showing the potential of the device to continuously monitor turbidity, sediment processes, and distinguish between organic and inorganic matter, at the different depths in the water column.

Proposal for an Embedded System Architecture Using a GNDVI Algorithm to Support UAV-Based Agrochemical Spraying.

An important area in precision agriculture is related to the efficient use of chemicals applied onto fields. Efforts have been made to diminish their use, aiming at cost reduction and fewer chemical residues in the final agricultural products. The use of unmanned aerial vehicles (UAVs) presents itself as an attractive and cheap alternative for spraying pesticides and fertilizers compared to conventional mass spraying performed by ordinary manned aircraft. Besides being cheaper than manned aircraft, small UAVs are capable of performing fine-grained instead of the mass spraying. Observing this improved method, this paper reports the design of an embedded real-time UAV spraying control system supported by onboard image processing. The proposal uses a normalized difference vegetation index (NDVI) algorithm to detect the exact locations in which the chemicals are needed. Using this information, the automated spraying control system performs punctual applications while the UAV navigates over the crops. The system architecture is designed to run on low-cost hardware, which demands an efficient NDVI algorithm. The experiments were conducted using Raspberry Pi 3 as the embedded hardware. First, experiments in a laboratory were conducted in which the algorithm was proved to be correct and efficient. Then, field tests in real conditions were conducted for validation purposes. These validation tests were performed in an agronomic research station with the Raspberry hardware integrated into a UAV flying over a field of crops. The average CPU usage was about 20% while memory consumption was about 70 MB for high definition images, with 4% CPU usage and 20.3 MB RAM being observed for low-resolution images. The average current measured to execute the proposed algorithm was 0.11 A. The obtained results prove that the proposed solution is efficient in terms of processing and energy consumption when used in embedded hardware and provides measurements which are coherent with the commercial GreenSeeker equipment.

Development of a Cost-Effective Optical Sensor for Continuous Monitoring of Turbidity and Suspended Particulate Matter in Marine Environment.

A cost-effective optical sensor for continuous in-situ monitoring of turbidity and suspended particulate matter concentration (SPM), with a production cost in raw materials less than 20 €, is presented for marine or fluvial applications. The sensor uses an infrared LED and three photodetectors with three different positions related to the light source-135º, 90º and 0º-resulting in three different types of light detection: backscattering, nephelometry and transmitted light, respectively. This design allows monitoring in any type of environment, offering a wide dynamic range and accuracy for low and high turbidity or SPM values. An ultraviolet emitter-receiver pair is also used to differentiate organic and inorganic matter through the differences in absorption at different wavelengths. The optical transducers are built in a watertight structure with a radial configuration where a printed circuit board with the electronic signal coupling is assembled. An in-lab calibration of the sensor was made to establish a relation between suspended particulate matter (SPM) or the turbidity (NTU) to the photodetectors' electrical output value in Volts. Two different sizes of seashore sand were used (180 µm and 350 µm) to evaluate the particle size susceptibility. The sensor was tested in a fluvial environment to evaluate SPM change during sediment transport caused by rain, and a real test of 22 days continuous in-situ monitoring was realized to evaluate its performance in a tidal area. The monitoring results were analysed, showing the SPM change during tidal cycles as well as the influence of the external light and biofouling problems.

Diferenças diagnósticas da citologia anal em meio líquido pelos métodos manual e automatizado na detecção de lesões anais

Introdução - A infecção pelo Papilomavírus Humano (HPV) é uma das Doenças Sexualmente Transmissíveis de maior incidência e prevalência no mundo. O vírus está envolvido na carcinogênese de cânceres. Mulheres com lesões no trato genital causadas pelo HPV têm maior risco de câncer anal. A avaliação microscópica do epitélio anal desempenha papel fundamental nas lesões pré-cancerosas e cancerosas. Objetivo - Comparar as diferenças diagnósticas obtidas através dos métodos manual e automatizado em amostras de citologia anal em meio líquido na caracterização de lesões intraepiteliais escamosas. Métodos - A coleta de citologia anal foi realizada através da escova Cytobrush da Kolplast®. Foram confeccionadas três lâminas previamente silanizadas por paciente. As pacientes com casos suspeitos e positivos foram convocadas para a Anuscopia. As lesões suspeitas foram biopsiadas e encaminhadas ao diagnóstico histopatológico. As citologias processadas de forma manual através do sistema Liqui-Prep®, foram fixadas em álcool etílico a 95% e, posteriormente, coradas pelo método de Papanicolaou. Já as citologias processadas de forma automatizada utilizaram o sistema ThinPrep®. As amostras citológicas foram encaminhadas para o exame de biologia molecular pela técnica de PCR HPV-Nested, desenvolvida pela empresa Exactgene Análise em DNA®, empregando se 13 tipos de alto risco e 5 de baixo risco. Resultado – Dos 80 casos avaliados no método manual e automatizado, respectivamente, os diagnósticos foram: 63 (78,75%) e 52 (65%) foram negativos para lesão intra-epitelial; 6 (7,5%) e 20 (25%) foram insatisfatórios para avaliação; ASC-US foram 9 (11,25%) e 6 (7,5%); LSIL apresentou 1 (1,25%) e 2 (2,5%); e HSIL em 1 (1,25%) e 0 (0%). Conclusão - o trabalho mostrou que a citologia feita de forma preventiva contra o câncer anal pode detectar lesões precursoras de malignidade na mucosa anal antes mesmo de qualquer sintoma clínico, possibilitando uma intervenção...

Introduction - The infection of Human Papillomavirus (HPV) is one of the sexually transmissible diseases with the highest incidence and prevalence in the world. . The virus is involved in the carcinogenesis of cancers. Women with a lesion in the genital tract caused by HPV have a higher risk of anal cancer. Microscopic evaluation of anal epithelium plays a important role in precancerous and cancerous lesions. Objective - Compare the diagnostic differences obtained through the manual and automated methods for anal cytology samples in liquid based in the characterization of squamous intraepithelial lesions. Methods - The collection of anal cytology was performed by cytobrush equipament for Kolplast®. Three slides were made previously silanized per patient. Patients with suspected and positive cases were called for anoscopy. Suspicious lesions were biopsied and sent to the histopathological diagnostic. The manually processed cytology through the Liqui-Prep® system, were fixed in 95% ethyl alcohol and then stained by Papanicolaou method. The automated processed cytology were passed through the ThinPrep® system. The cytological samples were sent for examination of molecular biology by PCR HPV-nested, developed by the company Exactgene Analysis DNA®, employing 13 high-risk types and 5 low risk. Results - From the 80 cases evaluated in manual and automated method, respectively, the diagnoses were: 63 (78.75%) and 52 (65%) were negative for intraepithelial lesion; 6 (7.5%) and 20 (25%) were unsatisfactory for evaluation; ASC-US were 9 (11.25%) and 6 (7.5%); LSIL showed 1 (1.25%) and 2 (2.5%); and HSIL in 1 (1.25%) and 0 (0%). Conclusion - the study showed that preventive cytology against anal cancer can detect precursor lesions of malignancy in the anal mucosa even before any clinical symptoms, allowing a faster response and less invasive than in cases of lesions in advanced stage.