scholarly journals On-the-go tropical soil sensing for pH determination using ion-selective electrodes

2018 ◽  
Vol 53 (11) ◽  
pp. 1189-1202 ◽  
Author(s):  
Fernanda Cristina de Souza Silva ◽  
José Paulo Molin

Abstract: The objective of this work was to assess the performance of an antimony ion-selective electrode (ISE) sensor system, using manual and automatic operating modes, for measuring the potential of hydrogen (pH), in real time, in Oxisols with different characteristics. Samples were manually collected and sent to a laboratory for determination of pH in water and calcium chloride, whose values were used as references. Another set of samples was also automatically collected using a commercial equipment, and readings were performed in manual mode. The performance parameters of the sensor system were calculated and evaluated. Part of the soil samples was used to assess the degree of influence of moisture in determining pH. Calibration lines were constructed. The statistical analysis revealed better results for the manual mode. Both modes of operation had errors superior to those accepted as a limit in laboratory techniques, however, with the possibility of high data density and with positive and promising results. Soil moisture interfered with the result of the readings. The sensor system yields a sampling density of 45 data per hectare, which represents a great contribution to the intensification of data for a better spatial evaluation of soil information.

2010 ◽  
Vol 20 (03) ◽  
pp. 209-218 ◽  
Author(s):  
JUNPING ZHANG ◽  
UWE KRUGER ◽  
XIAODAN WANG ◽  
DEWANG CHEN

The determination of principal curves relies on the arc-length as a global index to describe the middle of the data distribution. With a non-constant data distribution, however, curves that are constructed by the approach introduced in reference13 may not reflect the middle of data distribution, as demonstrated in this article. This is particularly so for curve segments that have a large curvature and a high data density. To overcome this problem, the paper revisits the projection of the samples onto the curve by incorporating Riemannian distances. This analysis suggests estimating the density value of each sample relative to its neighbors and utilize this value to compute the projection index for the curve. The use of density values, in turn, allows penalizing distances between samples along with the arc-length. In a similar fashion to conventional principal curves algorithms, for example proposed by Hastie and Stuetzle14 and Tibshirani,29 the incorporation of Riemannian distances gives rise to an iterative algorithm that includes a projection and a self-consistent step. Application studies to simulated and experimental data sets shows that the proposed modification has the potential to outperform existing algorithms in areas of high curvature under an non-constant data distribution.


2020 ◽  
Author(s):  
Xiaoyuan Wang ◽  
Pengfei Zhou ◽  
Jason Eshraghian ◽  
Chih-Yang Lin ◽  
Herbert Ho-Ching Iu ◽  
...  

<div>This paper presents the first experimental demonstration</div><div>of a ternary memristor-CMOS logic family. We systematically</div><div>design, simulate and experimentally verify the primitive</div><div>logic functions: the ternary AND, OR and NOT gates. These are then used to build combinational ternary NAND, NOR, XOR and XNOR gates, as well as data handling ternary MAX and MIN gates. Our simulations are performed using a 50-nm process which are verified with in-house fabricated indium-tin-oxide memristors, optimized for fast switching, high transconductance, and low current leakage. We obtain close to an order of magnitude improvement in data density over conventional CMOS logic, and a reduction of switching speed by a factor of 13 over prior state-of-the-art ternary memristor results. We anticipate extensions of this work can realize practical implementation where high data density is of critical importance.</div>


Chemosensors ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 76
Author(s):  
Aleksey V. Tarasov ◽  
Ekaterina I. Khamzina ◽  
Maria A. Bukharinova ◽  
Natalia Yu. Stozhko

In contemporary bioanalysis, monitoring the antioxidant activity (AOA) of the human skin is used to assess stresses, nutrition, cosmetics, and certain skin diseases. Non-invasive methods for skin AOA monitoring have certain advantages over invasive methods, namely cost-effectiveness, lower labor intensity, reduced risk of infection, and obtaining results in the real-time mode. This study presents a new flexible potentiometric sensor system (FPSS) for non-invasive determination of the human skin AOA, which is based on flexible film electrodes (FFEs) and membrane containing a mediator ([Fe(CN)6]3–/4–). Low-cost available materials and scalable technologies were used for FFEs manufacturing. The indicator FFE was fabricated based on polyethylene terephthalate (PET) film and carbon veil (CV) by single-sided hot lamination. The reference FFE was fabricated based on PET film and silver paint by using screen printing, which was followed by the electrodeposition of precipitate containing a mixture of silver chloride and silver ferricyanide (SCSF). The three-electrode configuration of the FPSS, including two indicator FFEs (CV/PET) and one reference FFE (SCSF/Ag/PET), has been successfully used for measuring the skin AOA and evaluating the impact of phytocosmetic products. FPSS provides reproducible (RSD ≤ 7%) and accurate (recovery of antioxidants is almost 100%) results, which allows forecasting its broad applicability in human skin AOA monitoring as well as for evaluating the effectiveness of topically and orally applied antioxidants.


MethodsX ◽  
2021 ◽  
pp. 101476
Author(s):  
Andrea Acosta-Dacal ◽  
Cristian Rial-Berriel ◽  
Ricardo Díaz-Día ◽  
María del Mar Bernal-Suárez ◽  
Manuel Zumbado ◽  
...  

2015 ◽  
Vol 9 (1) ◽  
pp. 92-98 ◽  
Author(s):  
Quanhua Hou ◽  
Wenhui Wang

To further study the effects of public service facilities on the land use intensity at regulatory planning level and enhance the scientific determination of land use intensity, this paper expounds the influence mechanism and factors of the public service facilities on land use intensity in regulatory planning, and conducts quantitative evaluation of the influence factors through theoretical analysis, mathematical analysis and analytic hierarchy process etc. The results show that the influence mechanism of public service facilities on the land use intensity goes throughout all three levels of regulatory planning. Different characteristics of public service facilities on each level determine their different influence factors and take effect on the land use intensity index of the corresponding level, thus affecting the determination of the block floor area ratio. Based on this, this paper proposes a method to determine the land use intensity in regulatory planning under the restriction of public service facilities and completes the test in practice, which may provide a reference for determining the land use intensity in regulatory planning.


2021 ◽  
Vol 285 ◽  
pp. 02007
Author(s):  
Ivan Masienko ◽  
Sergey Shevchenko ◽  
Kirill Glytyan

The paper presents the determination of main parameters and operating modes of scattered centrifugal devices of technical units when using them in the technology with scattered sowing when performing the technological operation of sowing rice in liquid-flexible soil. Theoretical studies of the dependence of design features of the blade of a spreading disk on the number of blades installed on it and the radius of curvature of the end bend on the height of blades are carried out. The values of the diameter of the disk of a centrifugal dispenser and parameters of blades are set, which will increase the uniformity of distribution of seed material for a given width of a gripper and reduce its consumption.


1998 ◽  
Vol 9 (11) ◽  
pp. 1809-1820 ◽  
Author(s):  
Hartmut Gall ◽  
Andrew Muir ◽  
John Fleming ◽  
Rolf Pohlmann ◽  
Lothar Göcke ◽  
...  
Keyword(s):  

2004 ◽  
Vol 112 (2-3) ◽  
pp. 278-285 ◽  
Author(s):  
Sadao Omata ◽  
Yoshinobu Murayama ◽  
Christos E. Constantinou

Author(s):  
I. Tarabukin

According to regulatory documents, welding can be performed at ambient temperatures from minus 15 ° C to plus 45 ° C. When laying gas pipelines at a lower outside temperature, it is necessary to organize their heating to the required temperature. In this case, the temperature of the heated air should not be more than plus 60 ° C. If you start working with a polyethylene (PE) pipe at low temperatures, then the PE pipe will have completely different characteristics. The weld seam may not be reliable.


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