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Background: Stingless bees are vital pollinators and honey producers in the tropics. Research on stingless bees is generally underrepresented compared to the western honeybees, and while stingless bee studies from some regions are reported, there is a particular lack of reports on the species endemic to Sub-Saharan Africa. Since conventional entomological methods such as mark-recapture and radar harmonic tags suffer from limited observation counts and amount to a significant payload, fluorescent powder tagging offers a promising alternative to understanding their behavior. We deploy a hyperspectral fluorescence lidar monitors a 25-mm-wide transect in front of the hives. Results: During a 1 day study at the International Stingless Bee Center, near Kakum National Park, Ghana, 17,862 insects were observed with the lidar, of which 7520 were tagged with fluorescent dyes. Approximately half of the bees from the selected hives were successfully tagged, with an estimated misclassification of 1%. According to our limited data, the observed species, Meliponula bocandei and the Dactylurina staudingeri exhibited different activity patterns. D. staudingeri displayed a half-hour longer active day, with clear crepuscular activity peaks. In contrast, M. bocandei activity was diurnal, with less pronounced crepuscular peaks. Conclusions: We demonstrate how hyperspectral fluorescence lidar can monitor powder-tagged insects throughout the day. The monitored species revealed distinct activity patterns over the day. Our findings highlight the potential of this technology as a valuable tool for understanding insect behavior and environmental preferences of species, in situ, which could potentially give clues of response to climate changes of these critical species. [ABSTRACT FROM AUTHOR]

Torres, J.G.; Botero, C.M., and Jaramillo-Velez, A., 2024. A comparison of beach profile methods from technical, operational, and economical dimensions. Journal of Coastal Research, 40(2), 257–267. Charlotte (North Carolina), ISSN 0749-0208. Beach profiles provide evidence of the spatiotemporal variability of the coastal surface. Despite being a popular parameter, few references compare a large number of available methods, which would be relevant at both scientific and management levels. This research comparatively analyzed 15 methods for measuring beach profiles, according to three basic criteria: technical, operational, and economic. The comparison was carried out on two beaches in the Gulf of Urabá (Colombia) with different morphological and sedimentary characteristics (dissipative profile with medium sands and reflective profile with pebbles) and on a concrete profile that served as a control. The methods were classified as manual or technological according to their nature and complexity. The total station method was used as a reference method to perform the statistical analysis with the other methods, because it presented less variation compared with other high-precision methods in a control profile. Using the analytical hierarchical process technique, it was found that the manual methods dominated the technological methods. The Puleo method obtained the best result when weighing the three evaluation criteria. As for the economic factors, the manual methods presented a marked difference over the technological ones, and the Emery method was the most economical. These results reject the postulate that insufficient beach profiling data are caused by a lack of budget, because they show that equipment costing just tens of dollars and operated by unqualified personnel are sufficiently reliable and provide consistent results for coastal management. [ABSTRACT FROM AUTHOR]

Smart manufacturing is the convergence of Industry 4.0 technologies that modernize production systems, with a growing demand for real-time active management to maximize processes. Companies with outdated, non-communicative or non-data-transmitting machine tools urgently need new technologies to ensure competitiveness. A viable option is smart retrofitting, which involves upgrading legacy equipment to bring them into the digital age. This article presents a study on the potential of digitizing legacy machine tools to improve productivity and surface quality through low-cost instrumentation. Low-cost sensors and hardware were installed on a universal lathe for continuous and real-time monitoring of the turning process. The results confirmed the influence of cutting speed and feed rate on surface finish, while the instrumentation showed good results in monitoring rotation and feed rate. The results of this paper contributes to recent research in process monitoring and enables a solid analysis of the benefits of real-time monitoring of machining in universal mechanical lathes. [ABSTRACT FROM AUTHOR]

Evapotranspiration (ET) constitutes the largest loss of water from subtropical grassland and wetland ecosystems, yet data in much of the world have high uncertainty at the landscape scale as there is little information on plant water use. Additionally, anthropogenic alterations to grasslands are a major threat globally and alter ecosystem water use, but the impact of these changes is often unquantified. A major reason for this is the complexity and expense of field‐based ET quantification methods such as agricultural lysimeters and eddy covariance systems. Accurate measurements of ET are critical for sustainable water management. This study developed two different low‐cost lysimeters—weighing‐type and water level‐based, to measure ET under partly controlled conditions for single species as well as mixed grassland and wetland communities. Lysimeters were placed in an open‐sided, transparent‐roofed shadehouse and watered periodically. ET values were then compared with (i) actual ET from an eddy covariance tower onsite, (ii) vapour transport‐based reference ET models (FAO Penman–Monteith, modified Turc and Abtew simple radiation models), and (iii) reference ET data customized for vegetation types from the Florida Automated Weather Network (FAWN). Both weighing‐type and water level lysimeters yielded seasonal patterns and annual magnitudes similar to other ET methods. Annual ET measurements from single‐species weighing‐type lysimeters (ranging from 881 to 1278 mm for four plant species, n = 5 per species, 20 in total) and water level lysimeters (1085 ± 306 mm, plant community average, n = 31) were about 10–20% lower than reference ET models (~1300 mm) and similar to FAWN data (1050 mm). Actual ET from eddy covariance was 722 mm for 10 months (missing data for February and March), while weighing lysimeter measurements for the dominant grass Paspalum notatum was 885 mm for the same 10 months. While rainfall exclusion and watering can result in ET differing from actual field conditions, low‐cost lysimeters can provide an independent measure of ET for comparison with regional ET models/remote sensing data lacking field validation. Thereby, low‐cost lysimeters are potentially useful for water resources and ecosystem management in data‐poor regions of the world. [ABSTRACT FROM AUTHOR]

A yearlong wind and wave dataset derived from a cost-effective GPS wave buoy (Spotter) is compared to waves obtained from an accelerometer wave buoy (Datawell) and winds obtained from a collocated meteorological buoy. Overall, there was a strong correlation in bulk wave parameters obtained from the Spotter buoy and the Datawell buoy (RMSE of 0.06 m, 0.27 s, and 21.89° for significant wave height, mean wave period, and peak wave direction, respectively). Similarly, the bulk characteristics compared well when separating the directional wave spectra into sea and swell components with more scatter in mean wave periods for lower frequencies. Measurements of mean directional spread from the Spotter buoy were 7.51° larger than the Datawell, spreading more wave energy across different directions outside the peak direction. Additional analysis indicates that the increased directional spreading arises from a bias in the a1 and b1 spectral moments. Using the equilibrium frequency range of the wave energy spectrum, the Spotter buoy can derive wind speed and direction. This study found the Spotter buoy can report wind speed and direction with reasonable accuracy but underestimates wind speeds less than 4 m/s and greater than 8 m/s and was less accurate reporting wind directions oriented offshore. A comparison with a Spotter buoy in deeper water revealed the Spotter buoy further offshore was most accurate in reporting wind directions indicating this proxy-based measurement of wind speed and wind direction may be significantly influenced by fetch and local geography (e.g., large-scale cuspate coastlines).

The constant monitoring of active landslides, particularly those located in the proximity of populated areas or touristic places, is crucial for early warning and risk-management purposes. The commonly used techniques deploy expensive instrumentation that can be hardly afforded, especially by small mountain communities in which landslide events often occur repeatedly. In recent years, the scientific community, as well as the private sector, have devoted growing effort to reducing the costs of monitoring systems. In this work, we present a monitoring network based on single-frequency Global Positioning System (GPS) sensors that have been activated to monitor an active landslide in the Carnic Alps, North-Eastern Italy. The system, which was composed of 12 single-frequency GPS stations, one seismometric station coupled with a single-frequency GPS instrument for real-time monitoring, and one permanent dual-frequency GPS station located in a stable area, provided daily reports of the landslide motion to the local authorities and administration. We show that this system is a valuable, flexible, and cost-effective tool for quick landslide characterization, and has high potential to be used as a landslide early warning system in case of emergency situations. [ABSTRACT FROM AUTHOR]

The design and implementation of a performance protocol for local seismicity monitoring, is presented. A low-cost seismograph was installed in an area of high seismic activity in Evgiros, Lefkada Island, Greece, collocated with a high resolution 24-bit digitizer equipped with a broadband seismometer. A testing list of 28 local events with different epicenters and magnitudes has been compiled while acquisition data from the conventional seismograph and the proposed one were analyzed. Stochastic data analysis was used to compare these recordings on the same test site with different logging devices. The obtained results showed a satisfactory outcome in the performance of the proposed low-cost seismograph. Even though noise was present, P and S waves were clearly recorded with distinct amplitudes and therefore this arrival time difference, when compared with the one originating from the conventional seismograph, was found to be insignificant. Moreover, through a known magnitude equation, it manages to calculate earthquake's local magnitude with a deviation of ± 0.4, a result that can be further improved. Lastly, spectral content analysis revealed almost identical waveforms with equivalent relative frequency distributions between the devices being compared. [ABSTRACT FROM AUTHOR]

• Ultrasonic guided wave measurements require specialized instrumentation. • 5 MHz measurements on rock bolts with low-cost (USD 1110) equipment. • Narrowband excitation, averaging and filtering used to increase SNR. • Achieved propagation distance of 9 m equivalent to 9000 wavelengths. • Pre-amplification used to overcome internal noise in low-cost USB oscilloscope. Guided wave ultrasound offers the ability to inspect slender structures from a single transducer location. However, the propagation of guided waves is more complex than the propagation of bulk waves used in conventional ultrasonic testing, and the experimental equipment required is more sophisticated. Typical equipment is expensive and may limit research and industrial application. This paper investigates what can be achieved by using low-cost instrumentation for laboratory measurements. The application is the measurement of guided waves in rock bolts (cylindrical rods) at relatively high frequencies (5 MHz). The dispersive wave propagation requires the use of narrowband excitation signals. The use of a bench-top waveform generator and oscilloscope is compared to the use of a compact and low-cost USB oscilloscope, which includes an arbitrary waveform generator. The introduction of a pre-amplifier mitigated the poorer noise performance of the USB oscilloscope, and comparable results were obtained from the two setups. It is demonstrated that waves propagated 9 m in a free rock bolt, with 10 dB/m attenuation, could be detected and analyzed with a measurement setup costing approximately USD 1110. [ABSTRACT FROM AUTHOR]

This article describes a portable low-cost device for performing electrochemical impedance spectroscopy (EIS) measurements, which is based on an off-the-shelf TeensyDuino. The instrument does not make use of other components, such as operational amplifiers, so it can be readily set up by anyone having a Teensy device and some resistors. Teensy 3.2, Teensy 3.5, and Teensy 3.6 can be used to realize the EIS system. The instrument can measure the impedance in the frequency range from 0.01 to 50 000 Hz, and by selecting the shunt resistor, it can be adapted to different impedance values. No special instrumentation is required for the system calibration. The proposed system uncertainty is less than 5% for an impedance of up to $50 {~\mathrm {k\Omega }}$ , a value which is lower than the usual intrinsic uncertainty of most corrosion experiments. [ABSTRACT FROM AUTHOR]

The constant monitoring of active landslides, particularly those located in the proximity of populated areas or touristic places, is crucial for early warning and risk-management purposes. The commonly used techniques deploy expensive instrumentation that can be hardly afforded, especially by small mountain communities in which landslide events often occur repeatedly. In recent years, the scientific community, as well as the private sector, have devoted growing effort to reducing the costs of monitoring systems. In this work, we present a monitoring network based on single-frequency Global Positioning System (GPS) sensors that have been activated to monitor an active landslide in the Carnic Alps, North-Eastern Italy. The system, which was composed of 12 single-frequency GPS stations, one seismometric station coupled with a single-frequency GPS instrument for real-time monitoring, and one permanent dual-frequency GPS station located in a stable area, provided daily reports of the landslide motion to the local authorities and administration. We show that this system is a valuable, flexible, and cost-effective tool for quick landslide characterization, and has high potential to be used as a landslide early warning system in case of emergency situations.

We describe some practical and empirically validated multivariate sensor calibration methods, which have allowed us to successfully obtain usable data from low-cost, low-precision sensors and signal conditioning electronics; we demonstrate the efficacy of these methods with real examples of nonlinear correction of thermocouple measurements from errors originated by the simultaneous influence of the cold junction and the temperature of the signal conditioning and digitizing electronic circuit components. [ABSTRACT FROM AUTHOR]

Increasing the productivity while maintaining the quality of manufactured products is essential in the present industrial context. In this sense, the use of robotic devices in manufacturing facilities is increasing due to the advantages related to flexibility, repeatability, and low-cost, when compared to machining centers. However, a lack of digital connectivity between machines within the manufacturing system is a fact. Thus, in this paper, a low-cost instrumentation, sensing, and cloud technologies are proposed to monitor robotized manufacturing processes by digitalization of traditional robot arms. As a case study, a drilling process of different aircraft materials is performed to prove the digital integration. So, the results showed an interesting potential of the proposed methodology, especially in the case of material removal processes performed by robotized cells that are still challenging for conventional robots due to the lack of rigidity of their components. [ABSTRACT FROM AUTHOR]

Featured Application: Low-cost MEMS (Micro Electro-Mechanical Systems) accelerometers are very interesting sensors with which to monitor land and infrastructure. The synergy between accelerometers and low-cost GNSS (Global Navigation Satellite System) receivers represents both an interesting topic and a highly promising technique for monitoring angular and linear deformations through an integrated approach. Observation and monitoring of landslides and infrastructure is a very important basis for land planning, human activities, and safety. Geomatic techniques for deformation monitoring have usually involved GNSS and total station measurements or, more generally, expensive geodetic instruments, but other techniques, such as SAR (Synthetic Aperture Radar), can be efficiently applied. Using low-cost sensors could be an interesting alternative solution if the accuracy requirements can be satisfied. This paper shows the results obtained for tilt measurements using MEMS accelerometers, which were combined with mass-market GNSS sensors for monitoring five sites located on landslides. The use of a MEMS-like inclinometer requires an important calibration process to remove bias and improve the solution's accuracy. In this paper, we explain the MEMS calibration procedure employed, with a simple and cheap solution. The results indicate that with a simple calibration, it is possible to improve measurement accuracy by one order of magnitude, reaching an angular accuracy of a few hundredths of a degree, verified by an independent technique. [ABSTRACT FROM AUTHOR]

Global Navigation Satellite System (GNSS) technology is widely used for geodetic monitoring purposes. However, in cases where a higher risk of receiver damage is expected, geodetic GNSS receivers may be considered too expensive to be used. As an alternative, low-cost GNSS receivers that are cheap, light, and prove to be of adequate quality over short baselines, are considered. The main goal of this research is to evaluate the positional precision of a multi-frequency low-cost instrument, namely, ZED-F9P with u-blox ANN-MB-00 antenna, and to investigate its potential for displacement detection. We determined the positional precision within static survey, and the displacement detection within dynamic survey. In both cases, two baselines were set, with the same rover point equipped with a low-cost GNSS instrument. The base point of the first baseline was observed with a geodetic GNSS instrument, whereas the second baseline was observed with a low-cost GNSS instrument. The results from static survey for both baselines showed comparable results for horizontal components; the precision was on a level of 2 mm or better. For the height component, the results show a better performance of low-cost instruments. This may be a consequence of unknown antenna calibration parameters for low-cost GNSS antenna, while statistically significant coordinates of rover points were obtained from both baselines. The difference was again more significant in the height component. For the displacement detection, a device was used that imposes controlled movements with sub-millimeter accuracy. Results, obtained on a basis of 30-min sessions, show that low-cost GNSS instruments can detect displacements from 10 mm upwards with a high level of reliability. On the other hand, low-cost instruments performed slightly worse as far as accuracy is concerned.

Many households use solid fuels for cooking and heating purposes. There is currently a knowledge gap in our understanding of the variations in indoor air quality throughout the household as most of the studies focus on the areas in the close proximity of the cookstove. A low-cost wireless particulate matter (PM) sensor network was developed and deployed in households in Raipur, India to establish the spatio-temporal variation of PM concentrations. The data from multiple sensors were acquired in real-time with a wireless system. Data collected from the sensors agreed well (R 2 =0.713) with the reference data collected from a commercially available instrument. Low spatial variability was observed within the kitchen due to its small size and poor ventilation – a common feature of most rural Indian kitchens. Due to insufficient ventilation from open doors and windows, high PM concentrations similar to those found in the kitchen were also found in the adjoining rooms. The same household showed significantly different post-extinguished cookstove PM concentration decay rates (0.26 mg/m 3 -min and 0.87 mg/m 3 -min) on different days, owing to varying natural air exchange rates (7.68 m 3 /min and 37.40 m 3 /min). [ABSTRACT FROM AUTHOR]

Growing access to tap water and consequent expansion of water distribution systems has created numerous challenges to maintaining water quality between the treatment node and final consumer. Despite all efforts to develop sustainable monitoring systems, there is still a lack of low cost, continuous and real time devices that demonstrate potential for large-scale implementation in wide water distribution networks. The following work presents a study of a low-cost, optofluidic sensor, based on Trypthopan Intrinsic Fluorescence. The fluorospectrometry analysis performed (before sensor development) supports the existence of a measurable fluorescence output signal originating from the tryptophan contained within pathogenic bacteria. The sensor was mounted using a rapid prototyping technique (3D printing), and the integrated optical system was achieved with low-cost optical components. The sensor performance was evaluated with spiked laboratory samples containing E. coli and Legionella, in both continuous and non-continuous flow situations. Results have shown a linear relationship between the signal measured and pathogen concentration, with limits of detection at 1.4 × 103 CFU/mL. The time delay between contamination and detection of the bacteria was practically null. Therefore, this study supports the potential application of tryptophan for monitoring drinking water against water pathogens.

The high cost of acoustic Doppler ocean current meters means few are deployed in marine research studies. To address this problem, we have developed a low-cost robust current velocimeter based on the drag–tilt principle. The instrument tilts in response to current flow, for which the angle and direction of tilt are related to the water velocity. Static analytic approximation shows a sigmoid-type tilt response to increasing current speed. We detail a calibration method that models the relationship using a Gompertz curve. Calibration and field tests conducted near Magnetic Island, Australia, show a speed accuracy of 0.05 m/s for current speeds less than 0.6 m/s, and direction accuracy better than 15^\circ for current speeds greater than 0.15 m/s. This instrument should be especially useful for research projects where numerous or spatially dense measurements of ocean currents are required. [ABSTRACT FROM PUBLISHER]

This work proposes a simple device for thermometric titration using a contactless sensor. A low-cost infrared sensor (around $5) was adapted in a disposable, polystyrene vessel for monitoring the temperature to determine the endpoint of neutralization, redox, and complexation titrations, using a homemade syringe pump to titration control. Open-source software was developed to control the device using the Raspberry Pi platform and to perform automatic endpoint determination. The influence of sample volume, the flow rate of titrant, and sensor distance from the solution were evaluated to lower the variation among measurements. The parameters chosen in this regard were 10 mL of sample, 0.8 mL min−1 of titrant solution flow rate, and 3 cm of distance from the sensor to the solution. Results for the determination of the acidity of sauces and the ascorbic acid and calcium content of pharmaceutical products were compared with those from official compendia. The performance of the sensor also was compared with an infrared camera. The proposed method agreed with conventional ones to an extent ranging from 93% to 106%. The robust analytical performance and low cost of the system are essential features that could broaden the use of enthalpimetric analysis in several laboratories. Image 1 • A simple and low-cost device was proposed for thermometric titrations. • Inexpensive infrared thermometer was used and compared to an infrared camera. • Open-source software was developed for sensor control and endpoint determination. • Complexation, neutralization, and redox titrations were feasible. • Comparable results to infrared camera and reference methods were obtained. [ABSTRACT FROM AUTHOR]

Global Navigation Satellite System (GNSS) technology is widely used for geodetic monitoring purposes. However, in cases where a higher risk of receiver damage is expected, geodetic GNSS receivers may be considered too expensive to be used. As an alternative, low-cost GNSS receivers that are cheap, light, and prove to be of adequate quality over short baselines, are considered. The main goal of this research is to evaluate the positional precision of a multi-frequency low-cost instrument, namely, ZED-F9P with u-blox ANN-MB-00 antenna, and to investigate its potential for displacement detection. We determined the positional precision within static survey, and the displacement detection within dynamic survey. In both cases, two baselines were set, with the same rover point equipped with a low-cost GNSS instrument. The base point of the first baseline was observed with a geodetic GNSS instrument, whereas the second baseline was observed with a low-cost GNSS instrument. The results from static survey for both baselines showed comparable results for horizontal components; the precision was on a level of 2 mm or better. For the height component, the results show a better performance of low-cost instruments. This may be a consequence of unknown antenna calibration parameters for low-cost GNSS antenna, while statistically significant coordinates of rover points were obtained from both baselines. The difference was again more significant in the height component. For the displacement detection, a device was used that imposes controlled movements with sub-millimeter accuracy. Results, obtained on a basis of 30-min sessions, show that low-cost GNSS instruments can detect displacements from 10 mm upwards with a high level of reliability. On the other hand, low-cost instruments performed slightly worse as far as accuracy is concerned. [ABSTRACT FROM AUTHOR]

Growing access to tap water and consequent expansion of water distribution systems has created numerous challenges to maintaining water quality between the treatment node and final consumer. Despite all efforts to develop sustainable monitoring systems, there is still a lack of low cost, continuous and real time devices that demonstrate potential for large-scale implementation in wide water distribution networks. The following work presents a study of a low-cost, optofluidic sensor, based on Trypthopan Intrinsic Fluorescence. The fluorospectrometry analysis performed (before sensor development) supports the existence of a measurable fluorescence output signal originating from the tryptophan contained within pathogenic bacteria. The sensor was mounted using a rapid prototyping technique (3D printing), and the integrated optical system was achieved with low-cost optical components. The sensor performance was evaluated with spiked laboratory samples containing E. coli and Legionella, in both continuous and non-continuous flow situations. Results have shown a linear relationship between the signal measured and pathogen concentration, with limits of detection at 1.4 × 103 CFU/mL. The time delay between contamination and detection of the bacteria was practically null. Therefore, this study supports the potential application of tryptophan for monitoring drinking water against water pathogens. [ABSTRACT FROM AUTHOR]