scholarly journals Soil and Plant Nutrient Analysis with a Portable XRF Probe Using a Single Calibration

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2118
Author(s):  
João Antonangelo ◽  
Hailin Zhang
Keyword(s):  
Polynomial Regression ◽  
Fluorescence Probe ◽  
Soil Nutrient ◽  
Calibration Model ◽  
Statistical Parameters ◽  
Nutrient Analysis ◽  
Forage Plant ◽  
Plant Samples ◽  
Wide Range ◽  
Single Calibration

A portable X-ray fluorescence probe (pXRF) is a tool that is used to measure many elements quickly and efficiently in various samples, without any pretreatment. However, each type of sample generally requires different calibrations to be accurate. To overcome this, our work evaluated the efficacy of determining several elements in forage plant samples using the ‘Soil Nutrient and Metal’ calibration in a commercially available pXRF probe, envisioning that a single calibration can be used to measure samples of different matrixes. For this, the net intensity of the pXRF probe was determined in place of the concentration values that are obtained directly from measurements. Elemental concentrations (P, K, Ca, Mg, S, Cu, Fe, Zn, and Mn) from forage plant samples, collected across Oklahoma, US, were assessed in a representative number of ‘modeling’ and ‘validation’ (independent dataset) samples. Linear regression (LR) associated with the d-index, polynomial regression (PR), and power regression (PwR) were tested for predictions, producing many statistical parameters associated with the models that were used for comparison goals. The pXRF elemental data provided highly reliable predictions of K, S, Zn, and Mn regardless of the regression model. Although all models can be reliable in prediction of Ca and Fe concentrations, the PwR provided better root mean square error (RMSE) values. The predictions of Mg concentrations were less reliable, although highly significant; however, the P and Cu predictions were not acceptable. Our work successfully showed that, once established, a single calibration curve that covers a wide range of concentrations of several elements in soils and plant tissues enables both soil and plant samples to be analyzed. This suggests that manufacturers can develop a new calibration model for a commercially available pXRF probe that covers a wide variety of heterogeneous samples.

scholarly journals Exploring the physical controls of regional patterns of flow duration curves – Part 4: A synthesis of empirical analysis, process modeling and catchment classification

2012 ◽  
Vol 16 (11) ◽  
pp. 4483-4498 ◽  
Author(s):  
M. Yaeger ◽  
E. Coopersmith ◽  
S. Ye ◽  
L. Cheng ◽  
A. Viglione ◽  
...  
Keyword(s):  
Low Flow ◽  
Middle Portion ◽  
Qualitative Synthesis ◽  
Statistical Parameters ◽  
Regional Patterns ◽  
Flow Duration ◽  
Analysis Process ◽  
Wide Range ◽  
Physical Controls ◽  
Flow Duration Curves

Abstract. The paper reports on a four-pronged study of the physical controls on regional patterns of the flow duration curve (FDC). This involved a comparative analysis of long-term continuous data from nearly 200 catchments around the US, encompassing a wide range of climates, geology, and ecology. The analysis was done from three different perspectives – statistical analysis, process-based modeling, and data-based classification – followed by a synthesis, which is the focus of this paper. Streamflow data were separated into fast and slow flow responses, and associated signatures, and both total flow and its components were analyzed to generate patterns. Regional patterns emerged in all aspects of the study. The mixed gamma distribution described well the shape of the FDC; regression analysis indicated that certain climate and catchment properties were first-order controls on the shape of the FDC. In order to understand the spatial patterns revealed by the statistical study, and guided by the hypothesis that the middle portion of the FDC is a function of the regime curve (RC, mean within-year variation of flow), we set out to classify these catchments, both empirically and through process-based modeling, in terms of their regime behavior. The classification analysis showed that climate seasonality and aridity, either directly (empirical classes) or through phenology (vegetation processes), were the dominant controls on the RC. Quantitative synthesis of these results determined that these classes were indeed related to the FDC through its slope and related statistical parameters. Qualitative synthesis revealed much diversity in the shapes of the FDCs even within each climate-based homogeneous class, especially in the low-flow tails, suggesting that catchment properties may have become the dominant controls. Thus, while the middle portion of the FDC contains the average response of the catchment, and is mainly controlled by climate, the tails of the FDC, notably the low-flow tails, are mainly controlled by catchment properties such as geology and soils. The regime behavior explains only part of the FDC; to gain a deeper understanding of the physical controls on the FDC, these extremes must be analyzed as well. Thus, to completely separate the climate controls from the catchment controls, the roles of catchment properties such as soils, geology, topography etc. must be explored in detail.

Analysis of structures of flat planting machines

2021 ◽  
Vol 13 (1) ◽  
pp. 140-148
Author(s):  
Andrіі Slabkyі ◽  
◽  
Olexandr Manzhilevskyy ◽  
Olexandr Polishchuk ◽  
◽  
...  
Keyword(s):  
Cutting Tool ◽  
Relative Movement ◽  
Statistical Parameters ◽  
Abrasive Finishing ◽  
Wide Range ◽  
Uneven Wear ◽  
Lapping Machine ◽  
Numerical Program ◽  
Hydraulic Pulse

One of the methods of material processing is considered, which allows to obtain high geometric accuracy and low surface roughness of parts, namely their abrasive finishing. The high quality of machining of parts in this way is due to the use of coordinated relative movement of the workpiece and the cutting tool. According to the kinematic features, most lapping machines can be divided into two groups: machines with oscillating working motion and machines with rotating lapping motion. The machines of the first group are more common due to the simplicity of their design and versatility. However, the possibility of their use is limited by the size range of the workpieces and uneven wear of the cutting tool and, as a consequence, the uneven surface treatment of the part. The machines of the second group are considered the most versatile, as they allow processing a wide range of parts, varying in shape and size, but they are also not without such a disadvantage as uneven wear of the cutting tool with all the corresponding consequences. Improving the efficiency of abrasive finishing by complicating the trajectory of the relative movement of the tool and the part, ie the formation of a unique mutual working movement of the lapping and the movement of the workpiece, is one of the most common areas. The main disadvantage of equipment that provides processing of parts on this principle is, in most cases, limited regulation of the operating parameters of the cutting process, so this area remains promising and has broad prospects for development. The constructive scheme of the hydraulic-pulse flat-lapping machine offered in work thanks to a combination of advantages of the hydraulic-pulse drive with use of numerical program control will allow to provide unique mutual multi-movement of preparation and the lapping tool with a possibility of adjustment of its parameters in the course of processing. Purposeful choice of the shape and density of the trajectory of the working movement of the tool will form a micro relief of the treated surface with the necessary statistical parameters and low roughness.

scholarly journals Changes of arthropod diversity across an altitudinal ecoregional zonation in Northwestern Argentina

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4117 ◽  
Author(s):  
Andrea X. González-Reyes ◽  
Jose A. Corronca ◽  
Sandra M. Rodriguez-Artigas
Keyword(s):  
Species Richness ◽  
Polynomial Regression ◽  
Species Turnover ◽  
Predictor Variable ◽  
Elevational Gradient ◽  
Pitfall Trap ◽  
Northwestern Argentina ◽  
Higher Taxa ◽  
Total Species Richness ◽  
Wide Range

This study examined arthropod community patterns over an altitudinal ecoregional zonation that extended through three ecoregions (Yungas, Monte de Sierras y Bolsones, and Puna) and two ecotones (Yungas-Monte and Prepuna) of Northwestern Argentina (altitudinal range of 2,500 m), and evaluated the abiotic and biotic factors and the geographical distance that could influence them. Pitfall trap and suction samples were taken seasonally in 15 sampling sites (1,500–4,000 m a.s.l) during one year. In addition to climatic variables, several soil and vegetation variables were measured in the field. Values obtained for species richness between ecoregions and ecotones and by sampling sites were compared statistically and by interpolation–extrapolation analysis based on individuals at the same sample coverage level. Effects of predictor variables and the similarity of arthropods were shown using non-metric multidimensional scaling, and the resulting groups were evaluated using a multi-response permutation procedure. Polynomial regression was used to evaluate the relationship between altitude with total species richness and those of hyperdiverse/abundant higher taxa and the latter taxa with each predictor variable. The species richness pattern displayed a decrease in species diversity as the elevation increased at the bottom wet part (Yungas) of our altitudinal zonation until the Monte, and a unimodal pattern of diversity in the top dry part (Monte, Puna). Each ecoregion and ecotonal zone evidenced a particular species richness and assemblage of arthropods, but the latter ones displayed a high percentage of species shared with the adjacent ecoregions. The arthropod elevational pattern and the changes of the assemblages were explained by the environmental gradient (especially the climate) in addition to a geographic gradient (the distance of decay of similarity), demonstrating that the species turnover is important to explain the beta diversity along the elevational gradient. This suggests that patterns of diversity and distribution of arthropods are regulated by the dissimilarity of ecoregional environments that establish a wide range of geographic and environmental barriers, coupled with a limitation of species dispersal. Therefore, the arthropods of higher taxa respond differently to the altitudinal ecoregional zonation.

scholarly journals Evaluation of Unsupervised Change Detection Methods Applied to Landslide Inventory Mapping Using ASTER Imagery

2018 ◽  
Vol 10 (12) ◽  
pp. 1987 ◽  
Author(s):  
Rocío Ramos-Bernal ◽  
René Vázquez-Jiménez ◽  
Raúl Romero-Calcerrada ◽  
Patricia Arrogante-Funes ◽  
Carlos Novillo
Keyword(s):  
Change Detection ◽  
Vegetation Index ◽  
Thermal Emission ◽  
Principal Component ◽  
Detection Methods ◽  
Detection Accuracy ◽  
Data Types ◽  
Statistical Parameters ◽  
Wide Range ◽  
The World

Natural hazards include a wide range of high-impact phenomena that affect socioeconomic and natural systems. Landslides are a natural hazard whose destructive power has caused a significant number of victims and substantial damage around the world. Remote sensing provides many data types and techniques that can be applied to monitor their effects through landslides inventory maps. Three unsupervised change detection methods were applied to the Advanced Spaceborne Thermal Emission and Reflection Radiometer (Aster)-derived images from an area prone to landslides in the south of Mexico. Linear Regression (LR), Chi-Square Transformation, and Change Vector Analysis were applied to the principal component and the Normalized Difference Vegetation Index (NDVI) data to obtain the difference image of change. The thresholding was performed on the change histogram using two approaches: the statistical parameters and the secant method. According to previous works, a slope mask was used to classify the pixels as landslide/No-landslide; a cloud mask was used to eliminate false positives; and finally, those landslides less than 450 m2 (two Aster pixels) were discriminated. To assess the landslide detection accuracy, 617 polygons (35,017 pixels) were sampled, classified as real landslide/No-landslide, and defined as ground-truth according to the interpretation of color aerial photo slides to obtain omission/commission errors and Kappa coefficient of agreement. The results showed that the LR using NDVI data performs the best results in landslide detection. Change detection is a suitable technique that can be applied for the landslides mapping and we think that it can be replicated in other parts of the world with results similar to those obtained in the present work.

Nano-structured GeySi1-y:H Films Deposited by Low Frequency Plasma for Photovoltaic Application

2008 ◽  
Vol 1127 ◽  
Author(s):  
Andrey Kosarev ◽  
Alfonso Torres ◽  
Carlos Zuniga ◽  
Marco Adamo ◽  
Liborio Sanchez
Keyword(s):  
Electronic Properties ◽  
Urbach Energy ◽  
Low Frequency ◽  
Localized States ◽  
Statistical Parameters ◽  
Nano Structure ◽  
Mean Values ◽  
Temperature Dependence Of Conductivity ◽  
Wide Range ◽  
Grain Distribution

ABSTRACTIn this work we present the study of fabrication, Ge incorporation, structure and electronic properties of nano-structured GeySi1-y:H films with y>0.5 prepared by low frequency (LF) PECVD. GeySi1-y:H films were deposited by LF PECVD at a frequency f= 110 kHz from SiH4+GeH4+H2 gas mixture. SiH4 and GeH4 flows were varied to fabricate the films in wide range of 0<y<l. Hydrogen dilution was varied in the range of RH =20 to 80. Structure of the films was studied by AFM and SEM with consequent image processing to extract statistical parameters such as grain distribution and mean values. Composition of the films was characterized by SIMS and EDX. Electronic properties were characterized by temperature dependence of conductivity, spectral dependence of optical absorption. Sub-gap absorption was characterized by Urbach energy, EU; and defect absorption, αD. We observed grain like nano-structure with Gauss distribution of grain diameters by both AFM and SEM measurements. The most interesting films had mean grain diameter<D> = 24.0±0.7 nm, dispersion D=11.0±0.2 nm and fill factor FF=0.313, Ge content y=0.96-0.97(by SIMS and EDS). These films showed also the lowest values of Urbach energy EU = 0.030 eV and low defect absorption αD = 5×102 cm −1 (at photon energy hv = 1.04 eV) indicating on low density of localized states in mobility gap. Doped films have been also fabricated and studied. Finally we shall discuss application of the above films in photovoltaic devices.

scholarly journals Long-Term Evaluation and Calibration of Low-Cost Particulate Matter (PM) Sensor

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3617 ◽  
Author(s):  
Hoochang Lee ◽  
Jiseock Kang ◽  
Sungjung Kim ◽  
Yunseok Im ◽  
Seungsung Yoo ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Low Cost ◽  
Sensor Nodes ◽  
Lookup Table ◽  
Calibration Model ◽  
Statistical Parameters ◽  
Sensor Platform ◽  
Calibration Algorithm ◽  
Term Evaluation ◽  
Spatio Temporal

Low-cost light scattering particulate matter (PM) sensors have been widely researched and deployed in order to overcome the limitations of low spatio-temporal resolution of government-operated beta attenuation monitor (BAM). However, the accuracy of low-cost sensors has been questioned, thus impeding their wide adoption in practice. To evaluate the accuracy of low-cost PM sensors in the field, a multi-sensor platform has been developed and co-located with BAM in Dongjak-gu, Seoul, Korea from 15 January 2019 to 4 September 2019. In this paper, a sample variation of low-cost sensors has been analyzed while using three commercial low-cost PM sensors. Influences on PM sensor by environmental conditions, such as humidity, temperature, and ambient light, have also been described. Based on this information, we developed a novel combined calibration algorithm, which selectively applies multiple calibration models and statistically reduces residuals, while using a prebuilt parameter lookup table where each cell records statistical parameters of each calibration model at current input parameters. As our proposed framework significantly improves the accuracy of the low-cost PM sensors (e.g., RMSE: 23.94 → 4.70 μ g/m 3 ) and increases the correlation (e.g., R 2 : 0.41 → 0.89), this calibration model can be transferred to all sensor nodes through the sensor network.

Quality assurance for soil nutrient analysis: A case study

1994 ◽  
Vol 25 (9-10) ◽  
pp. 1605-1627 ◽  
Author(s):  
V. H. Kennedy ◽  
A. P. Rowland ◽  
J. Parrington
Keyword(s):  
Quality Assurance ◽  
Soil Nutrient ◽  
Nutrient Analysis

scholarly journals Automated Soil Nutrient Content Analysis and Fertilizer Suggestion for Farmers

2019 ◽  
Vol 8 (4) ◽  
pp. 12830-12833
Keyword(s):  
Human Error ◽  
Soil Nutrient ◽  
Nutrient Content ◽  
Vital Role ◽  
Test Results ◽  
Human Errors ◽  
Nutrient Analysis ◽  
Analysis Process ◽  
Soil Nutrient Content ◽  
Sowing Period

In India agriculture and its practices plays the vital role, since more number of people are employed in that process. The agricultural process goes on with the sowing, maintenance and yield. The yield of the crop purely depends on the season, maintenance and the nutrient content available in the soil. Soil nutrient analysis has been made before sowing period with the help of soil testing laboratory, based on the laboratory results and the selected crops. End of the analysis process the fertilizer suggestion would be given to the farmer. In the existing system the analysis process is done manually and farmers would be given direct suggestion about the fertilizer. Since the process is repetitive it consumes more time and there may be chance of human error which may majorly affect the yield. The main aim of the proposed work is to design an Automated Fertilizer Suggestion (AFS) application to give effective suggestions to farmers about the fertilizers with respect to crops based on the soil test results. Our proposed application reduces the time, controls the human errors, avoids the over dumping of fertilizer in the soil and improves the yield.

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