scholarly journals A multi-model approach toward understanding iron fouling at rock-fill drainage sites along roadways in New Hampshire, USA

2020 ◽  
Vol 2 (6) ◽  
Author(s):  
Melissa A. Lombard ◽  
Pamela J. Lombard ◽  
Craig J. Brown ◽  
James R. Degnan
Keyword(s):  
New Hampshire ◽  
Salt Content ◽  
Specific Conductance ◽  
Boosted Regression Trees ◽  
Factors Affecting ◽  
Rock Fill ◽  
Deicing Salts ◽  
Geochemical Models ◽  
Roadway Construction ◽  
Physicochemical Data

AbstractFactors affecting iron fouling in wet areas adjacent to roadways were investigated by collecting field rock cut and aqueous physicochemical data; developing exploratory predictive models; and developing geochemical models. Basic data included the identification of iron fouling from aerial imagery and field visits at 374 New Hampshire rock cut locations, and their associated rock-fill sites. Based on field water quality measurements from wet areas at 36 of the rock-fill sites, the occurrence of iron fouling was associated with higher values of specific conductance, lower concentrations of dissolved oxygen and lower pH compared to areas without iron fouling. A statistical model, using boosted regression trees, was developed to predict the occurrence of iron fouling in wet areas adjacent to roadways where rock-fill from nearby rock cuts was used in roadway construction. The model was used to develop a continuous iron fouling probability map for the state of New Hampshire that can be used to better understand the occurrence of iron fouling. Geochemical models illustrate how iron fouling of waters increases along roadways built with fill from sulfidic rock cuts as a result of acid generation from pyrite dissolution and ferrous iron (Fe2+) oxidation and increases in areas with greater specific conductance from deicing runoff caused by cation exchange. More iron is precipitated as goethite in simulations that include pyrite, and in simulations with deicing salts added, indicating that rock-fill sites with rocks that contain pyrite and water with greater salt content could have enhanced iron fouling.

The role of Sphagnum fimbriatum in secondary succession in a road salt impacted bog

1987 ◽  
Vol 65 (11) ◽  
pp. 2270-2275 ◽  
Author(s):  
Douglas A. Wilcox ◽  
Richard E. Andrus
Keyword(s):  
Secondary Succession ◽  
Vegetative Reproduction ◽  
Salt Content ◽  
Laboratory Studies ◽  
Pore Waters ◽  
Deicing Salts ◽  
Salt Gradient ◽  
Belt Transect ◽  
Sphagnum Fimbriatum

Secondary succession of Sphagnum mosses was studied for 7 years along a belt transect in a bog that had been impacted by sodium chloride highway deicing salts. Laboratory studies on Sphagnum fimbriatum Wils., the dominant recolonizing species, were conducted to determine its salt tolerance level and ability to reproduce from spores and fragments across a salt gradient. Vegetative reproduction was also compared with that of four other recolonizing species. Sphagnum fimbriatum represented a high percentage of all recolonizing Sphagnum and generally began growing on low hummocks in quadrats where the salt content of the interstitial peat pore waters had dropped to about 300 mg/L as chloride. This salt concentration was also found to be the basic tolerance limit for mature plants and reproducing spores and fragments. The success of Sphagnum fimbriatum as a pioneer species seems to be associated with its prolific production and probable dispersal of spores, its superior vegetative reproduction, its tolerance of mineralized waters, and its ability to grow on hummocks out of direct contact with mineralized waters.

scholarly journals Correction to: A multi-model approach toward understanding iron fouling at rock-fill drainage sites along roadways in New Hampshire, USA

2020 ◽  
Vol 2 (8) ◽  
Author(s):  
Melissa A. Lombard ◽  
Pamela J. Lombard ◽  
Craig J. Brown ◽  
James R. Degnan
Keyword(s):  
New Hampshire ◽  
Rock Fill ◽  
Model Approach

Watershed factors affecting stream acidification in the White Mountains of New Hampshire, USA

1987 ◽  
Vol 11 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Scott W. Bailey ◽  
James W. Hornbeck ◽  
C. Wayne Martin ◽  
Donald C. Buso
Keyword(s):  
New Hampshire ◽  
White Mountains ◽  
Factors Affecting ◽  
Stream Acidification

The farmers' perceptions of ANPS pollution and its influencing factors in Poyang Lake Region, China

2015 ◽  
Vol 73 (7) ◽  
pp. 1591-1598 ◽  
Author(s):  
Meiqiu Chen ◽  
Mengjiao Chen ◽  
Yanfei Lu ◽  
Liguo Wang ◽  
Yujiao Huang
Keyword(s):  
Prevention And Control ◽  
Large Scale ◽  
Poyang Lake ◽  
Arable Land ◽  
Pollution Prevention ◽  
Boosted Regression Trees ◽  
Factors Affecting ◽  
Poyang Lake Region ◽  
Lake Region ◽  
And Control

Individual farmers represent the main management entities of agricultural production under the family-contract responsibility system in China, and thus play crucial roles in the prevention and control of agricultural nonpoint source (ANPS) pollution. The analysis of the farmers' perceptions of ANPS pollution as well as the factors affecting their perceptions can provide valuable information for relevant policy-making to preserve high quality water in Poyang Lake and regional quality of arable land. Through a survey titled ‘Farmers' perceptions of ANPS pollution and farming behaviors in the Poyang Lake Region’, the data related to the perceptions of farmers on ANPS pollution were collected. The factors that affect their awareness of ANPS pollution were identified with the method of boosted regression trees (BRT). The results indicated that the farmers had awareness of the risk of ANPS pollution to some extent, but they lacked adequate scientific knowledge. Generally, they had no consciousness about how to prevent and control ANPS pollution and did not understand techniques needed for proper scientifically sound application of fertilizers and pesticides. The main factors that influenced their perceptions of ANPS pollution are (from high to low): the ratio of total income which comes from farming, per capita farmland, age, education level, and household income. Some measures targeted to improve the prevention and control of ANPS pollution were proposed: developing modern agricultural techniques and promoting large-scale farming, increasing public campaigns related to ANPS pollution prevention and control with the goal of raising the level of awareness of farmers, and reforming the methods used to promote science and technology in agriculture and encourage the proper use of chemical fertilizers and pesticides.

scholarly journals Factors Affecting Long-Term Trends in Global NDVI

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 372 ◽  
Author(s):  
Yujie Yang ◽  
Shijie Wang ◽  
Xiaoyong Bai ◽  
Qiu Tan ◽  
Qin Li ◽  
...  
Keyword(s):  
Central Asia ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Pearson Correlation ◽  
Central Africa ◽  
Kendall Test ◽  
Boosted Regression Trees ◽  
Underlying Distribution ◽  
Factors Affecting ◽  
Ecological Conservation

Diagnosing the evolution trends of vegetation and its drivers is necessary for ecological conservation and restoration. However, it remains unclear what the underlying distribution pattern of these trends and its correlation with some drivers at large spatial-temporal scales. Here we use the normalized difference vegetation index (NDVI) to quantify the activity of vegetation by Theil–Sen median trend analysis and the Mann–Kendall test, Pearson correlation analysis and Boosted regression trees (BRT) model. Results show that about 34% of the global continent area has experienced greening in the grid annual NDVI from 1982 to 2015. The major greening areas were observed in the Sahel, European, India and south China. Only 10% of the global continent land areas were browning, and these were observed in Canada, South America, central Africa and Central Asia. BRT model shows that rainfall is the most important factor affecting vegetation evolution (63.1%), followed by temperature (15%), land cover change (8.6%), population (6.5%), elevation (6.4%) and nightlight (0.4%). It’s about 21% of the world’s continent were affected by rainfall, mainly in arid regions such as central Asia and Australia. The main temperature-affected areas accounted for 36%, located near the equator or in high latitudes.

scholarly journals Factors Affecting the Dynamics of Frosty Pod Rot in the Main Cocoa Areas of Santander State, Colombia

Plant Disease ◽  
2019 ◽  
Vol 103 (7) ◽  
pp. 1665-1673 ◽  
Author(s):  
Yeirme Y. Jaimes ◽  
Fabienne Ribeyre ◽  
Carolina Gonzalez ◽  
Jairo Rojas ◽  
Edson L. Furtado ◽  
...  
Keyword(s):  
Partial Resistance ◽  
Good Practice ◽  
Boosted Regression Trees ◽  
Machine Learning Technique ◽  
Factors Affecting ◽  
Learning Technique ◽  
The Difference ◽  
Moniliophthora Roreri ◽  
Frosty Pod Rot ◽  
Different Levels

Frosty pod rot (FPR) caused by Moniliophthora roreri is the primary disease affecting cacao production in the major producing countries of the Americas and is one of the major threats to cacao worldwide. The incidence of FPR on clones with different levels of resistance was investigated in four localities of Santander State, Colombia, between July 2013 and May 2015. Dynamics of diseased pods were modeled using boosted regression trees, a machine learning technique that allows regressions to be performed without prior statistical assumptions. The results suggested that FPR epidemics varied according to plot location, clone, weeks of observation, and total pods produced. Dynamics in the phenology of pods had an effect on the epidemics, and this dynamic could partially explain the difference in resistance among clones. Although not total, partial resistance of ICS 95 was confirmed. An important wilt effect was observed, particularly in the resistant clones; consequently, differences in harvested pods were not significant among clones. Pod stripping remains a good practice for the management of the disease and this practice could also have an effect on the pod dynamics and wilt phenomenon.

Aerosols, Aerodynamics, and Atomic Analysis

1978 ◽  
Vol 32 (2) ◽  
pp. 181-187 ◽  
Author(s):  
R. K. Skogerboe ◽  
K. W. Olson
Keyword(s):  
Salt Content ◽  
Aerodynamic Characteristics ◽  
Interference Effects ◽  
Factors Affecting ◽  
Transport Efficiency ◽  
Microwave Induced Plasma ◽  
Atomic Excitation ◽  
Design Systems ◽  
Atomic Analysis ◽  
Suppression Effects

The suppression of atomic excitation in a microwave-induced plasma due to the presence of sodium has been studied for three different nebulization systems. Evaluation of the factors affecting this effect has shown that its occurrence depends on the nature of the analytical aerosol introduced and the aerodynamic features of the sample nebulization system. The results indicate that the sodium suppression effects observed can be largely accounted for by reductions in the analyte transport efficiency due to changes in the aerodynamic characteristics of the aerosol resulting from variations in the salt content of the nebulized solutions. It is further shown that these effects may be generally predicted on the basis of fluid mechanical principles and that these may be used to design systems to eliminate the interferences. The study underscores the essentiality of considering aerodynamic factors in formulating mechanistic explanations for interference effects in flames and plasmas.

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