scholarly journals Settling of Road-Deposited Sediment: Influence of Particle Density, Shape, Low Temperatures, and Deicing Salt

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3126
Author(s):  
Steffen H. Rommel ◽  
Laura Gelhardt ◽  
Antje Welker ◽  
Brigitte Helmreich
Keyword(s):  
Particle Density ◽  
Influencing Factor ◽  
Fluid Temperature ◽  
Road Runoff ◽  
Important Process ◽  
Treatment Efficiency ◽  
Deicing Salt ◽  
Deicing Salts ◽  
Proposed Model ◽  
Settling Column

Separation of particulate matter (PM) is the most important process to achieve a reduction of contaminants present in road runoff. To further improve knowledge about influencing factors on the settling of road-deposited sediment (RDS), samples from three sites were collected. Since particle size distribution (PSD) has the strongest effect on settling, the samples were sieved to achieve comparable PSDs so that the effects of particle density, shape, fluid temperature, and deicing salt concentration on settling could be assessed using settling experiments. Based on the experimental data, a previously proposed model that describes the settling of PM was further developed and validated. In addition, RDS samples were compared to a standard mineral material, which is currently in use to evaluate treatment efficiency of stormwater quality improvement devices. The main finding was that besides PSD, particle density is the most important influencing factor. Particle shape was thoroughly described but showed no significant improvement of the prediction of the settled mass. Temperature showed an effect on PM settling; deicing salts were negligible. The proposed models can sufficiently predict the settling of RDS in settling column experiments under varying boundary conditions and are easily applicable.

Use of Fly Ash to Minimize Deicing Salt Damage in Concrete Pavements

2017 ◽  
Vol 2629 (1) ◽  
pp. 24-32 ◽  
Author(s):  
Prannoy Suraneni ◽  
Vahid J. Azad ◽  
O. Burkan Isgor ◽  
W. Jason Weiss
Keyword(s):  
Fly Ash ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Concrete Pavements ◽  
Scanning Calorimetry ◽  
Deicing Salt ◽  
Performance Specification ◽  
Hydrated Cement Paste ◽  
Deicing Salts ◽  
Damage In Concrete

Premature damage has been observed at the joints in numerous concrete pavements where calcium chloride and magnesium chloride deicing salts have been used. This damage results from a reaction between the deicing salt and the calcium hydroxide (CH) in the hydrated cement paste. This reaction leads to the formation of an expansive product known as calcium oxychloride (CAOXY). The use of supplementary cementitious materials as a replacement for cement has been proposed to reduce the CH that is available in the mixture to react with the deicing salts. Reducing the CH can reduce the amount of CAOXY that forms. In this study, mixtures representative of paving concrete were made with cements and fly ashes from across the country. CH amounts were determined by using thermogravimetric analysis, and CAOXY amounts were determined by using low-temperature differential scanning calorimetry. Various replacement levels of fly ash were used to demonstrate that the main parameter that influences the amounts of CH and CAOXY that form is the replacement level of fly ash. This paper proposes that a prescriptive specification requiring 35% cement replacement by volume with fly ash would reduce the damage caused by CAOXY formation and further proposes a performance specification to limit the CAOXY formation to below 15 g/100 g paste.

scholarly journals Evaluation of the relative roles of a vegetative filter strip and a biofiltration swale in a treatment train for road runoff

2016 ◽  
Vol 75 (4) ◽  
pp. 987-997 ◽  
Author(s):  
Kelsey Flanagan ◽  
Philippe Branchu ◽  
David Ramier ◽  
Marie-Christine Gromaire
Keyword(s):  
Climatic Conditions ◽  
Relative Importance ◽  
Road Runoff ◽  
Treatment Efficiency ◽  
Filter Strip ◽  
Storm Water Management Model ◽  
The Road ◽  
Vegetative Filter Strip ◽  
Treatment Train ◽  
Us Epa

In order to determine the relative importance of a vegetative filter strip and a biofiltration swale in a treatment train for road runoff, US EPA Storm Water Management Model was used to model infiltration and runoff from the filter strip. The model consisted of a series of subcatchments representing the road, the filter strip and the side-slopes of the swale. Simulations were carried out for different rain scenarios representing a variety of climatic conditions. In addition, a sensitivity analysis was conducted for the model's different parameters (soil characteristics and initial humidity, roughness, geometry, etc.). This exercise showed that for the system studied, the majority of road runoff is treated by the filter strip rather than the biofiltration swale, an effect observed especially during periods of low-intensity rainfall. Additionally, it was observed that the combination of infiltration of road runoff in the filter strip and direct rainfall on the system leads to a significant and variable dilution of the runoff reaching the swale. This result has important implications for evaluating the treatment efficiency of the system.

scholarly journals Determination of the covalent bond dipole moments with CLPO analysis

2018 ◽  
pp. 105-108
Author(s):  
T. Nikolaienko
Keyword(s):  
Dipole Moment ◽  
Particle Density ◽  
Dipole Moments ◽  
Covalent Bond ◽  
Frobenius Norm ◽  
Total Charge ◽  
Covalent Bonds ◽  
Moment Vector ◽  
Proposed Model ◽  
Nuclear Contribution

Basing on the orbitals localization method which provides the most accurate (in a Frobenius norm sense) approximation for the reduced one-particle density matrix of the molecule, the model is proposed for partitioning the dipole moment of the molecule into additive contributions, defined in CLPO basis. By augmenting the proposed model with the Ruedenberg scheme for partitioning the nuclear contribution to the dipole moment, the contributions to the dipole moment associated with particular covalent bonds and lone pairs of the atoms were determined. Using the datasets composed of 11410 12-atomic molecules with zero total charge and the set of 613 conformations of electroneutral 2'-deoxycytidine-5'-monophosphate molecule, it has been found that the error in approximating the total dipole moment of the molecule by the sum of localized contributions, determined in the framework of the proposed model, is close to 10%, and is noticeably below the similar error when only the NPA charges are used to compute the approximate dipole moment. The typical angle between the true dipole moment vector and the dipole moment vector approximated with the proposed model is 5.5 deg.

scholarly journals Comparative Study between Membrane Bioreactor MBR and Rotating Biological Contactors RBC for Greywater Treatment

2021 ◽  
Vol 12 (4) ◽  
pp. 107-111
Author(s):  
Amr M. Abdelkader ◽  
Keyword(s):  
Pilot Plant ◽  
Biological Treatment ◽  
Membrane Bioreactor ◽  
Settling Tank ◽  
Suspended Solid ◽  
Treatment Efficiency ◽  
Proposed Model ◽  
Nitrification Process ◽  
Rotating Biological Contactors ◽  
Work Done

Greywater is the major part of water consumption in houses. Greywater should be treated to complying with the specifications for several purposes such as toilet flush, landscaping irrigation, and agriculture. The treatment efficiency of both MBR and RBC systems was investigated by using a verified mathematical model. The simulation program GPS-X (version 6.0) was used to simulate both MBR and RBC systems. The simulation model for biological treatment for both MBR and RBC systems is based on Activated Sludge Model 1 (ASM1). The experimental data for model calibration and verification for the MBR system were taken from experimental work done at Tubitak, Marmara Research Center, Turkey ATASOY. As well as the RBC proposed model was verified also by using RBC experimental results for a pilot plant according to BABAN. The RBC pilot plant consists of three units, The first is the RBC unit, the second unit is the settling tank and the last unit is the disinfection tank. The results of the MBR plant showed that the removal efficiencies of the greywater were: 95% for COD; 95% for BOD5; 96% for TKN; 92% for NH4+ and 99% for TSS. Whereas, the results of the RBC show that, The BOD efficiency removal was ranged between about 93.0 to 96.0 %, and for the total SS removal was ranged between 84.0 to 95.0 %. The MBR system provides complete nitrification and suspended solid removal. The RBC system provides less nitrification process and suspended solid removal. The effluent of the rotating biological contactors units for the greywater could be reused after filtration and disinfection with minimal cost of operation. The effluent of the membrane bioreactor unit needs only disinfection before reuse.

Deicing Salt (Sodium Chloride) Damage to Pinusresinosa Ait.

1975 ◽  
Vol 5 (4) ◽  
pp. 546-556 ◽  
Author(s):  
Edward Sucoff ◽  
Ray Feller ◽  
Dennis Kanten
Keyword(s):  
Sodium Chloride ◽  
Forest Trees ◽  
Warm Up ◽  
Deicing Salt ◽  
Deicing Salts ◽  
Osmotic Potentials

Four studies demonstrated that NaCl spray was the primary cause of browning of Pinusresinosa Ait. along salted roads. All damaged needles had high Cl and when analyzed, high Na; the symptoms produced by spraying NaCl on forest trees appeared identical with highway symptoms; damage occurred in the spring warm-up after a winter buildup of Na and Cl; damage was greatest where use of deicing salts was greatest. Coincidence between Cl in needles and on needles indicated spray was the source of the salt. Brown needles had higher osmotic potentials (Ps) in proportion to NaCl content, but high Ps was probably incidental to damage. Still unexplained are the occasional green highway pines with high Na and Cl.

scholarly journals Performance of Concrete Pavement in the Presence of Deicing Salts and Deicing Salt Cocktails

2016 ◽  
Author(s):  
Prannoy Suraneni ◽  
Jonathan Monical ◽  
Erol Unal ◽  
Yaghoob Farnam ◽  
Chiara Villani ◽  
...  
Keyword(s):  
Concrete Pavement ◽  
Deicing Salt ◽  
Deicing Salts

Column studies to determine mercury settling in road runoff

2012 ◽  
Vol 65 (3) ◽  
pp. 463-470
Author(s):  
XiaoJun Zuo ◽  
DaFang Fu ◽  
He Li
Keyword(s):  
Rainfall Intensity ◽  
Removal Rate ◽  
Initial Distribution ◽  
Road Runoff ◽  
Column Studies ◽  
Rainfall Characteristics ◽  
Settling Column ◽  
The Impact ◽  
The Relationship ◽  
Settling Process

A study was performed using a settling column to remove mercury (Hg) from road runoff. The emphasis was placed on the relationship between Hg removal and critical settling velocities, as well as the distribution of total suspended solids (TSS). The impact of rainfall characteristics and temperature on Hg removal was also discussed. Results indicated that Hg removal was significant within the initial 30 min of the settling process. The Hg removal rate increased with the decrease of critical settling velocity, and this trend became gradually significant, which could be used as an important reference for the optimization of sedimentation basin design. Hg removal at different settling times was significantly related to initial distribution of TSS. The impact of rainfall intensity on Hg removal was greater than other parameters of precipitation features, followed by rainfall. In addition, Hg removal was moderately related to temperature. The effect of antecedent dry periods on Hg removal was restricted by rainfall and rainfall intensity.

Online Shopping Characteristics and Their Influence on Female Buying Behavior

2020 ◽  
Vol 18 (4) ◽  
pp. 1-29
Author(s):  
Prashant Raman
Keyword(s):  
Customer Service ◽  
Online Shopping ◽  
Influencing Factor ◽  
Major Influence ◽  
Buying Behavior ◽  
Proposed Model ◽  
Willingness To Buy ◽  
Tpb Model ◽  
Online Shoppers ◽  
Willingness To Use

Female online shoppers in the Indian e-commerce industry are growing day by day and the online vendors need to understand their shopping habits to approach them in a better way. A conceptual model is proposed that extends the theory of planned behaviour (TPB) model with three additional constructs namely, trust, convenience, and customer service. The proposed model is examined by means of questionnaire responses collected from around 529 online shoppers. The study reveals that customer service has the major influence on the female's attitude to shop online and perceived behavioural control acts as the most influencing factor in female shoppers' willingness to buy online. The overall descriptive power of the proposed model has an R2 of 52% for female's willingness to use online shopping and an R2 of 46% for attitude towards online shopping. Since it is difficult to attract new shoppers and retain existing customers, excellent customer service can be the answer to the problems related to customer retention and customer loyalty in the online context.

scholarly journals Control of Chloride Ion Corrosion by MgAlO x /MgAlFeO x in the Process of Chloride Deicing

2021 ◽  
Author(s):  
Dongdong Wang ◽  
Qi Zhu ◽  
Zipeng Xing ◽  
Lei Fang
Keyword(s):  
Corrosion Inhibitor ◽  
Corrosion Inhibitors ◽  
Freezing Point ◽  
Chloride Ion ◽  
Synthesis Temperature ◽  
Molar Ratio ◽  
Dsc Analysis ◽  
Deicing Salt ◽  
Deicing Salts ◽  
Chloride Salts

Abstract The corrosion inhibitor that is added to chloride deicing salt, whose anti-corrosion and low pollution is great significance. LDHs, calcined at high temperature were used as adsorbents to remove various anionic contaminants and it could reduce the solution's freezing point after adsorbing anions. Therefore, this paper reports the use of calcined LDHs as corrosion inhibitors in deicing salts. We analyzed that the removal ability of chloride ion MgAlFeOx was stronger than that of MgAlOx, reaching 85.50%, and the freezing point was lower than that of MgAlOx, the value was -12.0 °C. At the same time, we also found that CaCl2-MgAlOx and CaCl2-MgAlFeOx significantly reduce the corrosion of carbon steel and concrete compared with chloride salts, and CaCl2-MgAlFeOx has the lowest corrosion degree. Hence, we determined that MgAlFeOx was corrosion inhibitor in chloride deicing salt. The metal molar ratio, synthesis temperature and calcination temperature for preparation of MgAl/MgAlFe-LDHs were determined by XRD and TG-DSC analysis that are 9/2/1, 120 ºC and 500 ºC, respectively. The characteristics of MgAlFeOx after Fe3+ addition were studied in detail by Zeta, XRD, XPS, BET and SEM. The mechanism of corrosion inhibitor’s anticorrosion was determined, which was achieved by adsorption and neutralization.

scholarly journals Salt no longer travels through the Bohemian Forest along the Golden Trail, but halophytic neophytes do

2021 ◽  
Vol 11 (2) ◽  
pp. 91-100
Author(s):  
Zdenka Křenová ◽  
Zdeňka Chocholoušková ◽  
Vladimír Zýval
Keyword(s):  
Winter Maintenance ◽  
Deicing Salt ◽  
Ancient Trade ◽  
Central European Region ◽  
Bohemian Forest ◽  
Deicing Salts ◽  
High Conservation ◽  
The Bohemian Forest ◽  
High Concentrations ◽  
Trade Route

The Golden Trail, used for the transport of salt from alpine mines to the Czech Kingdom for centuries, was a crucial ancient trade route in the Central European region. The contemporary road I/4, copying the Golden Trail, plays the same role today. The I/4 is used year round with deicing salt, a common standard, applied for winter maintenance. Deicing salt is often used, even in sections where the I/4 passes through the Bohemian Forest and its protected areas. The effects of applying deicing salts on ecosystems in the region is well documented. In addition to many other effects, high concentrations of salt along the roads cause significant changes in plant communities. Plant species sensitive to salinity disappear and the abundance of halophytes increases. Roads are also trajectories for the migration of neophytes. Seeds or other propagules are transported with cargo or in car tires. In this paper, we present our findings on the pilgrimage of Plantago coronopus, a true halophyte, into the Bohemian Forest. We also describe the species’ colonisation strategy and human measures supporting its successful migration in a region of high conservation value.

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