scholarly journals Effect of PVA/PVAc Based Polymer Coating on Dust Reduction in Playground

2021 ◽  
Vol 11 (7) ◽  
pp. 3144
Author(s):  
In Kyu Jeon ◽  
Abdul Qudoos ◽  
Hyunseok Lee ◽  
Hong Gi Kim
Keyword(s):  
Polymer Coating ◽  
Soil Samples ◽  
Dust Exposure ◽  
Wind Effect ◽  
Specific Density ◽  
Coating Solution ◽  
Soil Particles ◽  
Permeability Characteristics ◽  
Dust Generation ◽  
Dust Reduction

Dust exposure is a serious threat to human health due to dermal contact, inhalation, and ingestion. Children are more vulnerable to dust than adults as a result of high rates of unintentional, or deliberate, ingestion and inhalation of dust. In this study, dust reduction in the playground due to coating of the soil particles with a PVA/PVAc-based solution was investigated. Soil particles were coated with varying amounts of coating solution and the samples were examined for various parameters e.g., specific density, moisture content, liquid and plastic limits, permeability, dust generation due to wind effect and human activity. The results demonstrated that coated soil samples showed improved permeability characteristics and reduced dust generation. These characteristics were improved by increased content of coating solution.

scholarly journals Potential relevance of Mortierella alpina as a source of ice nucleating particles in soil

2018 ◽  
Author(s):  
Franz Conen ◽  
Mikhail V. Yakutin
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Fungus ◽  
Soil Samples ◽  
Mortierella Alpina ◽  
Soil Particles ◽  
The Tropics

Abstract. Soil organic matter carries ice nucleating particles (INP) of which the origin is hard to define and that are active at slight supercooling. The discovery and characterisation of INP produced by the widespread soil fungus Mortierella alpina permits a more targeted investigation of the likely origin of INP in soils. We searched for INP with characteristics similar to those reported for M. alpina (INPM-like) in 20 soil samples from four areas in the northern midlatitudes and one area in the tropics. In the 15 samples where we could detect INPM-like, they constituted between 1 and 94 % (median 11 %) of all INP active at −10 °C or warmer associated with soil particles

An automatic, multichamber soil-washing apparatus for removing fungal spores from soil

1972 ◽  
Vol 18 (9) ◽  
pp. 1399-1404 ◽  
Author(s):  
J. Bissett ◽  
P. Widden
Keyword(s):  
Fungal Spores ◽  
Soil Washing ◽  
Soil Samples ◽  
Cross Contamination ◽  
Vegetative Mycelium ◽  
Soil Particles ◽  
Large Numbers

An automatic soil-washing apparatus is described which enabled the washing of fungus spores out of large numbers of soil samples simultaneously. Tests of the apparatus indicated that superficial spores were removed from most of the soil particles. This allowed organisms growing in soil as vegetative mycelium to be isolated more readily without the serious competition commonly encountered from organisms sporulating heavily in the soil. Virtually no cross-contamination of soil samples occurred in the multichambered apparatus.

scholarly journals An environmentally friendly soil improvement technology for sand and dust storms control

2019 ◽  
Vol 6 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Sareh Rajabi Agereh ◽  
Farshad Kiani ◽  
Kazem Khavazi ◽  
Hassan Rouhipour ◽  
Farhad Khormali
Keyword(s):  
Wind Velocity ◽  
Soil Loss ◽  
High Efficiency ◽  
Soil Stabilization ◽  
Soil Surface ◽  
Soil Samples ◽  
Dust Storms ◽  
Control Group ◽  
Soil Particles ◽  
And Control

Background: Dust storms occur when unchecked, strong, or turbulent winds combine with exposed loose and dried soil surfaces. Sand and dust storms have a significant impact on society, economy, and environment at local, regional, and global levels. The environmental and health hazards of such storms cannot be permanently reduced, however, by taking appropriate measures, its impact can be reduced. The present study aimed to investigate the effects of microbial precipitation of calcium carbonate (CaCO3) as a biocompatible agent on soil stabilization and control of dust storms using ureaseproducing bacteria (UPB) as a biological improvement technique, which were isolated, identified, sprayed on the soil surface. Methods: For this purpose, the erosion of bio-cemented soil samples was investigated experimentally in a wind tunnel under the condition of wind velocity of 0 to 98 km.h-1 in two soil types with sandy and silty texture in a completely randomized design with three replicates. Results: The investigation of the threshold wind velocity of soil particles showed that soil particles began to move at velocity of 8 and 10 km.h-1 in silty and sandy soils, respectively, but in all biological samples (MICP), particles did not move until the wind speed reached 97 km.h-1. It was also revealed that the weight loss of all MICP-treated samples at different wind velocities was significantly reduced compared to the control group. Differences in the amount of soil loss among bio-cemented samples and control treatments were even superior at higher velocities, so that at velocities more than 57 km.h-1, soil losses increased significantly in the control group, while in soils treated with bacteria, soil loss was very low (about 2.5 kg.m-2.h-1). Comparison of the bacteria used in this study also showed that Bacillus infantis and Paenibacillus sp3 had high efficiency in controlling dust storms. Conclusion: The formation of abrasion-resistant surface layers on soil samples treated by biocementation showed that cementation by biological methods could be an effective way to stabilize surface particles and control sand and dust storms.

Study on Mechanism of Freeze-Thaw Cycles Induced Changes in Soil Strength Using Electrical Resistivity and X-Ray Computed Tomography

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Xiaoliang Yao ◽  
Lili Fang ◽  
Jilin Qi ◽  
Fan Yu
Keyword(s):  
Computed Tomography ◽  
Electrical Resistivity ◽  
Triaxial Compression ◽  
Friction Angle ◽  
Soil Samples ◽  
Soil Particles ◽  
X Ray ◽  
Freeze Thaw ◽  
Apparent Cohesion ◽  
X Ray Computed

In this study, freeze-thaw cycles were conducted on samples of a fine grained soil from the Qinghai–Tibetan plateau which had been prepared with different dry unit weights. During freeze-thaw cycles, electrical resistivity was measured. The soil samples were also scanned by X-ray computed tomography (CT) before and after freeze-thaw cycles. Unconsolidated and drained (UD) triaxial compression test was performed to obtain the apparent friction angle and cohesion. Changes in the arrangement and connections between soil particles were analyzed so as to investigate the mechanisms of changes in the strength parameters. The electrical resistivity increased in all samples, regardless of the different original dry unit weights, which implies that in all cases the arrangement of soil particles became more irregular and attached area between soil particles was increased. These changes contributed to the increase of apparent friction angle. On the other hand, the CT scans indicated that, depending upon the original dry unit weight, freeze-thaw cycles induced strengthening or deterioration in particle connections, and thus apparent cohesion was increased or decreased. With three freeze-thaw cycles, changes in microstructure of soil samples led to increases or decrease in both the apparent friction angle and cohesion.

scholarly journals Assessing sediment enrichment ratio in Mai-Negus catchment, northern Ethiopia

2014 ◽  
Vol 9 (No. 1) ◽  
pp. 38-45 ◽  
Author(s):  
G.B. Tesfahunegn ◽  
P.G.L. Vlek
Keyword(s):  
Soil Nutrients ◽  
Soil Samples ◽  
Limited Resources ◽  
Enrichment Ratio ◽  
Soil Parameters ◽  
Northern Ethiopia ◽  
Soil Particles ◽  
Fine Soil ◽  
Central Ridge ◽  
Field Indicators

Soil degradation is a threat to sustainable development in Ethiopia. However, degradation indicators, such as sediment enrichment ratio (SER), are not adequately documented in literature. This study aims to investigate the SER of different erosion-status sites (aggrading, stable, eroded) in various landforms in Mai-Negus catchment, northern Ethiopia. The erosion-status sites in the landforms were identified using field indicators, and soil samples were collected for analysis of selected soil parameters. In this study, due to the ratio of aggrading to eroded or stable sites at catchment and landform levels, the SER of soil nutrients and fine soil particles was > 1. But due to the ratio of aggrading to eroded sites in the landforms the average SER of the soils were higher (1.42–7.22) as compared to the ratios of aggrading to stable sites (1.10–3.66). The SER significantly (P ≤ 0.05) differed among the landforms, which indicated differences in the effect of erosion. The relationships between the SER of fine soil particles and soil nutrients were strong. Thus, priority for introducing appropriate anti-erosion measures should be given to sources of high SER sites such as the mountainous and central ridge landforms in the catchment using the limited resources available.

Environmental Dust Exposure as a Factor Contributing to an Increase in Escherichia coli O157 and Salmonella Populations on Cattle Hides in Feedyards

2008 ◽  
Vol 71 (10) ◽  
pp. 2078-2081 ◽  
Author(s):  
M. F. MILLER ◽  
G. H. LONERAGAN ◽  
D. D. HARRIS ◽  
K. D. ADAMS ◽  
J. C. BROOKS ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Positive Sample ◽  
Dust Exposure ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Probable Number ◽  
Airborne Dust ◽  
E Coli ◽  
Dust Generation ◽  
The Impact

A study was conducted to determine the impact of exposure to dust in the cattle load-out area in feedyards on pathogen contamination of cattle hides. A total of 250 cattle hides were sampled during summer and fall months, which are associated with elevated prevalence of Escherichia coli O157 in West Texas. Animals were removed from their home pens and restrained in a chute and sampled prior to exposure to dust generated as a result of a simulated loading exercise. The cattle hides were sampled again after exposure to the loading dust to determine total numbers of pathogens on cattle hides on leaving their home pen (before loading) and on cattle hides after exposure to the dust in the loading area. Air and dirt samples from the home pens and the cattle load-out area were also collected. The presence of E. coli O157 and Salmonella was determined in all the samples, and when a positive sample was identified, the total numbers of these bacteria present were enumerated. The total numbers of pathogens increased after dust exposure; Salmonella counts increased from 1.09 log most probable number (MPN)/cm2 to 1.74 log MPN/cm2 after exposure, and E. coli O157 counts increased from 0.80 to 2.35 log MPN/cm2 after sampling. E. coli O157 and Salmonella were recovered from the air samples during dust generation at 6.66 and 11.1%, respectively. Salmonella and E. coli O157 prevalence was not changed and was not associated with the exposure to the dust. Results indicate airborne dust generated as a result of cattle movement and loading could be an important determining factor in total numbers of pathogens recovered on cattle hides.

scholarly journals Blockchain-Based Network Concept Model for Reliable and Accessible Fine Dust Management System at Construction Sites

2021 ◽  
Vol 11 (18) ◽  
pp. 8686
Author(s):  
Seungwon Cho ◽  
Muhammad Khan ◽  
Jaeho Pyeon ◽  
Chansik Park
Keyword(s):  
Network Architecture ◽  
Fine Dust ◽  
Fugitive Dust ◽  
Construction Sites ◽  
Concept Model ◽  
Open Platform ◽  
Dust Generation ◽  
Search Tool ◽  
Government Inspection ◽  
Dust Reduction

In total, 44.3% of particle matter 10 (PM10) is fugitive dust, and one of the main sources of fugitive dust generation in Korea is construction work (22%). Construction sites account for 84% of the total business places that have reported fugitive dust generation. Currently, the concentration of fine dust at construction sites is being remotely monitored by government inspection agencies through IoT sensors, but it is difficult to trust that appropriate fine dust reduction measures are being taken, because contractors can avoid taking these measures by submitting false reports or photos. In addition, since the fine dust monitoring system under government management is not an open platform and centralized system, residents near construction sites encounter difficulties in accessing information about fine dust. Therefore, in this study, we designed and constructed a blockchain network model to transparently and reliably provide network participants with the information associated with IoT data and fine dust reduction measures. To operate the blockchain network, we designed the chaincode, DApp, and network architecture. In addition, information on fine dust concentration and reduction measure photos were shared with the participants via the blockchain search tool (Hyperledger Explorer). The proposed blockchain network is expected to form a trust protocol among contractors, government inspection agencies, and citizens.

scholarly journals Pore distribution and classification of loess

2021 ◽  
Vol 261 ◽  
pp. 03002
Author(s):  
Qianqian Liu ◽  
Tiehang Wang
Keyword(s):  
Permeability Coefficient ◽  
Pore Diameter ◽  
Soil Samples ◽  
Permeability Test ◽  
Pore Characteristics ◽  
Permeability Characteristics ◽  
Profound Influence ◽  
Porosity Ratio ◽  
Scanning Electron

The micro-pore characteristics in undisturbed loess have a profound influence on the permeability characteristics. Based on the results of permeability test, it is proved that the permeability coefficient of soil samples with the same porosity ratio is different and the internal characteristics are diversified. The internal pores of undisturbed loess were studied by scanning electron microscopy (SEM). The results show that there are obvious differences in the internal microstructure of the original loess with the same porosity ratio. There are root holes in undisturbed loess, the number and size of which directly affect the value of permeability coefficient. With the increase of pore diameter, the pore size distribution changes gradually, and the influence of small pores is gradually weakened, while the influence of large pores is more obvious. Therefore, only the pore ratio parameter used in engineering can not completely describe the pore characteristics of soil, it is necessary to introduce other microscopic parameters to describe.

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