scholarly journals Laboratory Evaluations of Correction Equations with Multiple Choices for Seed Low-Cost Particle Sensing Devices in Sensor Networks

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3661 ◽  
Author(s):  
Wen-Cheng Vincent Wang ◽  
Shih-Chun Candice Lung ◽  
Chun Hu Liu ◽  
Chen-Kai Shui

To tackle the challenge of the data accuracy issues of low-cost sensors (LCSs), the objective of this work was to obtain robust correction equations to convert LCS signals into data comparable to that of research-grade instruments using side-by-side comparisons. Limited sets of seed LCS devices, after laboratory evaluations, can be installed strategically in areas of interest without official monitoring stations to enable reading adjustments of other uncalibrated LCS devices to enhance the data quality of sensor networks. The robustness of these equations for LCS devices (AS-LUNG with PMS3003 sensor) under a hood and a chamber with two different burnt materials and before and after 1.5 years of field campaigns were evaluated. Correction equations with incense or mosquito coils burning inside a chamber with segmented regressions had a high R2 of 0.999, less than 6.0% variability in the slopes, and a mean RMSE of 1.18 µg/m3 for 0.1–200 µg/m3 of PM2.5, with a slightly higher RMSE for 0.1–400 µg/m3 compared to EDM-180. Similar results were obtained for PM1, with an upper limit of 200 µg/m3. Sensor signals drifted 19–24% after 1.5 years in the field. Practical recommendations are given to obtain equations for Federal-Equivalent-Method-comparable measurements considering variability and cost.

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Ying Chen ◽  
Feng Wang ◽  
Yuanxi Jiang ◽  
Chen Wang ◽  
Liwen Yao ◽  
...  

Gastroesophageal reflux disease is a diversity disease that affects life quality of people in the world. Due to the complicated pathogenesis and variations in clinical manifestations, there is still no true gold standard for GERD diagnosis, and it is still difficult to diagnose this disease in some patients. The proton pump inhibitor’s diagnostic test (the PPI test) is noninvasive, of low cost, tied to treatment, and widely accepted. Our aim is to evaluate the diagnostic significance of coapplying a rabeprazole test with the SF-36 for GERD in this study. Our study shows that the SF-36 in combination with the rabeprazole test can screen GERD patients and increase the sensitivity and specificity of GERD diagnosis through reference to the change in SF-36 score before and after the treatment (65 in the trial).


Author(s):  
Maiara Luzia Grigoli OLIVIO ◽  
Elizângela Flávia Jacob ESTEVES ◽  
Dagmar Aparecida de Marco FERRO

Comumente o sulfato de alumínio é o coagulante químico utilizado nas Estações de Tratamentos para a clarificação da água, embora produza um lodo tóxico de difícil deposição no ambiente. No entanto, os coagulantes naturais como sementes de Moringa oleífera Lam. têm demonstrado vantagens para tratamento em comparação aos químicos, pela simplicidade de uso e baixo custo. O estudo objetivou analisar a eficiência coagulante da semente de Moringa oleífera na clarificação de água com turbidez e comparar com os parâmetros do coagulante químico sulfato de alumínio. As amostras de água foram coletadas no Córrego Jacu Queimado e as sementes colhidas em um plantio da própria espécie. Foram realizados, em laboratório, etapas sequenciais do experimento: comparação da eficiência da semente verde e seca, determinação da concentração e tempo de exposição da semente à água, comparação de agitação manual e magnética entre elas e do coagulante biológico com o químico, sendo analisados os aspectos físico, químico e biológico antes e após a adição de ambos. Observou-se que apenas a semente seca realiza a clarificação da água em comparação com os resultados das análises da água clarificada com o sulfato, determinando-se que 5 sementes são eficazes para tratar 1 litro de água com turbidez de até 25,0 NTU, considerando-se mais relevante a agitação manual para o efeito de coagulação e o aguardo de 2 horas para o término da decantação. Conclui-se, que a semente de Moringa é um coagulante biológico que se apresenta como alternativa para o tratamento de água com turbidez, porém, ainda não é indicada para a potabilidade. É preciso dar continuidade ao tratamento em busca de processos que visam melhorar a qualidade da água para aproximar-se aos parâmetros aceitáveis para o consumo humano.   Moringa oleífera Lam SEEDS: EFFICIENT USE OF BIOLOGICAL COAGULANT FOR WATER TURBIDITY TREATMENT, COMPARED TO ALUMINUM SULFATE CHEMICAL COAGULANT   ABSTRACT Aluminum sulfate is a chemical coagulant commonly used at Water Treatment Plants for water clarification, although it produces a toxic sludge of difficult deposition in the environment. However, natural coagulants such as Moringa oleíferaLam seeds have evidenced the advantages for the treatment when compared to chemicals, due to either their simplicity in and low cost.  This research aims at reviewing the efficient use of   Moringa oleífera seeds as coagulants for turbid water clarification as well as comparing the parameters of aluminum sulfate chemical coagulants. The water samples were collected at Córrego Jacu Queimado and the seeds were harvested from a crop of its own species. Sequential steps were performed in the lab for this experiment: Comparison of green and dry seeds efficiency, concentration and time of exposition of the seed to water measurements, comparison of manual and magnetic stirring among them and among biological and chemical coagulants, being analyzed physical, chemical and biological aspects before and after adding both of them. It was observed that only the dry seed enables water clarification when comparing the analysis results to sulfate water clarification, it was ascertained that 5 seeds are efficient to treat a liter of 25,0 NTU turbidity in water, considering as more relevant manual stirring for coagulation effect after a two-hour rest for decantation completion. It was concluded that Moringa seed is a biological coagulant presented as an alternative for turbid water treatment, although it is not indicated for drinkability. Further treatment is necessary in order to keep searching for processes that target to improve the quality of water and meeting acceptable parameters for water consumption.   Keywords: Biological Coagulant. Chemical Coagulant. Efficiency. Water Clarification. Comparative Parameters.


2017 ◽  
Vol 6 (1) ◽  
pp. 199-210
Author(s):  
Manuel Schneider ◽  
Alexander Jahn ◽  
Norbert Greifzu ◽  
Norbert Fränzel

Abstract. This article provides insight into the development of a powerful and low-cost chopper amplifier for piezoelectric pressure sensors and shows its possible applications for injection moulding machines. With a power supply of 3.3 volts and the use of standard components, a circuit is introduced which can be connected to a commercially available microcontroller without any additional effort. This amplifier is specialised for low frequencies and high-pressure environments. With the adjustment of the sample and chopper frequency by means of software, the amplifier can easily be adapted for other applications. This chopper amplifier is a very compact and cost-effective solution with a small number of required components. In this contribution, it will be shown that the amplifier has good results in various laboratory tests as well as in the production process. Furthermore, an approach to fuse data from force and pressure signals by using a Kalman filter will be presented. With this method, the quality of the sensor signals can be significantly improved. This article is an extension of our previous work in Schneider et al. (2016b).


Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4577
Author(s):  
Florentin Delaine ◽  
Bérengère Lebental ◽  
Hervé Rivano

The drastically increasing availability of low-cost sensors for environmental monitoring has fostered a large interest in the literature. One particular challenge for such devices is the fast degradation over time of the quality of their data. Therefore, the instruments require frequent calibrations. Traditionally, this operation is carried out on each sensor in dedicated laboratories. This is not economically sustainable for dense networks of low-cost sensors. An alternative that has been investigated is in situ calibration: exploiting the properties of the sensor network, the instruments are calibrated while staying in the field and preferably without any physical intervention. The literature indicates there is wide variety of in situ calibration strategies depending on the type of sensor network deployed. However, there is a lack for a systematic benchmark of calibration algorithms. In this paper, we propose the first framework for the simulation of sensor networks enabling a systematic comparison of in situ calibration strategies with reproducibility, and scalability. We showcase it on a primary test case applied to several calibration strategies for blind and static sensor networks. The performances of calibration are shown to be tightly related to the deployment of the network itself, the parameters of the algorithm and the metrics used to evaluate the results. We study the impact of the main modelling choices and adjustments of parameters in our framework and highlight their influence on the results of the calibration algorithms. We also show how our framework can be used as a tool for the design of a network of low-cost sensors.


2014 ◽  
Vol 16 (10) ◽  
pp. 2249-2258 ◽  
Author(s):  
Samuel Dauwe ◽  
Damiano Oldoni ◽  
Bernard De Baets ◽  
Timothy Van Renterghem ◽  
Dick Botteldooren ◽  
...  

The growing concern of citizens about the quality of their living environment and the emergence of low-cost microphones and data acquisition systems triggered the deployment of numerous noise monitoring networks spread over large geographical areas.


Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2477 ◽  
Author(s):  
Giuseppe Toscano ◽  
Vincenzo Alfano ◽  
Antonio Scarfone ◽  
Luigi Pari

The goal of this work was to test a patented pruning harvester and a mobile pelleting system specifically designed for the vineyard agripellet chain. Biomass was characterized before and after storage and after the pelleting stage. The performance, the fuel consumption, and the work quality of the harvester were assessed together with the productivity and the power consumption of the mobile pelleting system. Production costs of pellet were estimated for the whole logistic chain, considering two scenarios: Storage and pelleting directly at the farm site or at a dedicated location at variable distance from the fields. For comparison, the direct production of chips without pelleting was considered. Results indicate that harvester performance was quite good and comparable with commercial solutions; the chips produced exhibited excellent storage performance, allowing direct pelleting without forced drying; the pellet quality was good comparable with that produced from forestry biomass. From an economic point of view, in-field pelleting was the most cost-effective solution, with a good margin of profit up to 57€ t−1; on the other hand, when transport to an intermediate storage center is necessary, profit margin reduces gradually and fades off at an average 50 km distance from the fields.


2016 ◽  
Vol 20 (4) ◽  
Author(s):  
YAHAYA S. MOHAMMAD ◽  
EGBENYA M. SHAIBU-IMODAGBE ◽  
SUNDAY B. IGBORO ◽  
ABDUL-RAHEEM GIWA ◽  
CHARLES A. OKUOFU

<p>In this study, low-cost adsorbent was produced and applied in the treatment of Samaru stream water. Treatment of Samaru stream water was carried out in column mode to determine the efficiency of the low-cost adsorbent for improving the quality of Samaru stream water. To achieve this, the stream water samples were collected from three different points (point 1, 2 and 3) and the values of the following parameters were analyzed before and after treatment: pH, Electrical Conductivity (EC), Total Dissolved Solid (TDS), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Ammonium, Nitrate, Chloride, Iron (III), Copper (II), Lead (II) and Zinc (II). Results obtained from the study show that highest removal efficiency of 96.18 % was attained for chloride and this was followed by 91.76 %, 90.91 % and 90 % for iron (III), copper (II) and ammonium respectively while the least was 6.33 % (pH). Therefore, the high removal efficiency achieved for some sample parameters in the treatment of Samaru stream water implied that the low-cost adsorbent could be employed in the simultaneous removal of contaminants from a multicomponent system.</p>


2013 ◽  
Vol 20 (3) ◽  
pp. 91-106 ◽  
Author(s):  
Rachel Pizarek ◽  
Valeriy Shafiro ◽  
Patricia McCarthy

Computerized auditory training (CAT) is a convenient, low-cost approach to improving communication of individuals with hearing loss or other communicative disorders. A number of CAT programs are being marketed to patients and audiologists. The present literature review is an examination of evidence for the effectiveness of CAT in improving speech perception in adults with hearing impairments. Six current CAT programs, used in 9 published studies, were reviewed. In all 9 studies, some benefit of CAT for speech perception was demonstrated. Although these results are encouraging, the overall quality of available evidence remains low, and many programs currently on the market have not yet been evaluated. Thus, caution is needed when selecting CAT programs for specific patients. It is hoped that future researchers will (a) examine a greater number of CAT programs using more rigorous experimental designs, (b) determine which program features and training regimens are most effective, and (c) indicate which patients may benefit from CAT the most.


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