Quantification of Reduction in Hydraulic Conductivity and Skid Resistance Caused by Fog Seal in Low-Volume Roads

2017 ◽  
Vol 2657 (1) ◽  
pp. 99-108 ◽  
Author(s):  
Readul Mohammad Islam ◽  
Shams Arafat ◽  
Nazimuddin M. Wasiuddin
Keyword(s):  
Hydraulic Conductivity ◽  
Low Cost ◽  
Surface Friction ◽  
Application Rate ◽  
Application Rates ◽  
Low Volume Roads ◽  
Before And After ◽  
Road Type ◽  
Rate Of Recovery ◽  
Low Volume

Fog seal increases pavement life and postpones major rehabilitation. The reduction of permeability caused by fog sealing will reduce moisture-induced damage, but this benefit comes with a temporary loss of surface friction. However, quantifying the effectiveness of fog sealing by measuring permeability is a difficult task. Although fog seal may be a good low-cost maintenance option for low-volume roads, the rate of recovery of friction may be very slow because of less rubbing action between the fog-sealed surface and tires. Four low-volume parish roads in Caddo Parish, Louisiana, were selected for this study. Two emulsions, CSS-1H and E-Fog, with three application rates, were used to evaluate the reduction in hydraulic conductivity and to assess the characteristics of friction over time. Results showed that fog seal can be expected to be fully cured within 2.5 to 3.5 hours for an application rate of 0.2 to 0.4 gallons per square yard (gal/yd2). The same field cores were tested before and after fog sealing to quantify exactly the reduction in hydraulic conductivity. It was observed that fog seal has a significant potential to reduce hydraulic conductivity. Considering all four pavements and application rates of 0.1 to 0.22 gal/yd2, the average reduction in hydraulic conductivity was 38.5%. Reduction in hydraulic conductivity shows very slight sensitivity to the application rate. Irrespective of road type, emulsion, and application rate, fog seal causes a sudden drop in the International Friction Index parameter F60 by 20% to 40%. A fog-sealed surface does not return to the original level of friction after three months; however, the rate of recovery was the highest for the busiest of the observed Caddo Parish roads.

Otta Seals and Gravseals as Low-Cost Surfacing Alternatives for Low-Volume Roads: Experiences in South Africa

2003 ◽  
Vol 1819 (1) ◽  
pp. 338-342 ◽  
Author(s):  
Simon Oloo ◽  
Rob Lindsay ◽  
Sam Mothilal
Keyword(s):  
South Africa ◽  
Low Cost ◽  
Cost Savings ◽  
Cost Effective ◽  
Field Trials ◽  
Low Volume Roads ◽  
Kwazulu Natal ◽  
Traffic Volumes ◽  
Low Volume ◽  
To Come

The geology of the northeastern part of the province of KwaZulu–Natal, South Africa, is predominantly alluvial with vast deposits of sands. Suitable gravel sources are hard to come by, which results in high graveling and regraveling costs brought about by long haul distances and accelerated gravel loss. Most gravel roads carry fewer than 500 vehicles per day of which less than 10% are heavy vehicles. The high cost of regraveling has led to consideration of upgrading such roads to surfaced standard, even though traffic volumes do not justify upgrading. Traditional chip seals are expensive and cannot be economically justified on roads that carry fewer than 500 vehicles per day. The KwaZulu–Natal Department of Transport is actively involved in efforts to identify cost-effective alternative surfacing products for low-volume roads. Field trials were conducted with Otta seals and Gravseals, which have been used successfully in other countries, as low-cost surfacing products for low-volume roads. The Otta seal is formed by placing graded aggregates on a relatively thick film of soft binder that, because of traffic and rolling, works its way through the aggregates. Gravseal consists of a special semipriming rubberized binder that is covered by a graded aggregate. Both Otta seals and Gravseals provide relatively flexible bituminous surfaces suitable for low-volume roads. Cost savings are derived mainly from the broad aggregate specifications, which allow for the use of marginal materials.

Limited impacts of truck-based ultra-low-volume applications of mosquito adulticides on mortality in honey bees (Apis mellifera)

2017 ◽  
Vol 107 (6) ◽  
pp. 724-733 ◽  
Author(s):  
F.D. Rinkevich ◽  
J.W. Margotta ◽  
V. Pokhrel ◽  
T.W. Walker ◽  
R.H. Vaeth ◽  
...  
Keyword(s):  
Apis Mellifera ◽  
Honey Bee ◽  
Mosquito Control ◽  
Application Rate ◽  
High Rate ◽  
Application Rates ◽  
Mosquito Mortality ◽  
Low Volume ◽  
High Label ◽  
Low Rate

AbstractAdulticides applied against mosquitoes can reduce vector populations during times of high arbovirus transmission. However, impacts of these insecticides on pollinators and other non-target organisms are of concern to mosquito control professionals, beekeepers and others. We evaluated mortality of Culex quinquefasciatus and Apis mellifera when caged insects were exposed to low and high label rates of four common adulticides (Aqua-Pursuit™ [permethrin], Duet® [prallethrin + sumithrin], Fyfanon® [malathion] and Scourge® [resmethrin]) at six distances up to 91.4 m from a truck-mounted ultra-low-volume sprayer. Honey bee mortality was both absolutely low (<10%) and low relative to mosquito mortality for most products, distances, and application rates. Exceptions were at the high rate of Fyfanon (honey bee mortality of 22–100% at distances ≤61 m) and the low rate of Scourge (mortality <10% for both insects). The greatest ratios of mosquito-to-honey bee mortality were found for the low rate of Fyfanon (30× greater) and the high rate of Duet (50× greater). Aqua-Pursuit and Fyfanon tended to increase mortality of both species at closer distances and at higher application rate; this was related to increased number and size of spray droplets. Wind speed and temperature had inconsistent effects on mortality of mosquitoes only. In this bioassay designed to have insects directly intercept insecticide droplets, mosquito adulticides applied at low rates and at >61 m had limited impacts on honey bee mortality while providing effective mosquito control.

scholarly journals Significance of Pyrolytic Temperature, Particle Size, and Application Rate of Biochar in Improving Hydro-Physical Properties of Calcareous Sandy Soil

Agriculture ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1293
Author(s):  
Abdulaziz G. Alghamdi ◽  
Abdulrasoul Al-Omran ◽  
Arafat Alkhasha ◽  
Zafer Alasmary ◽  
Anwar A. Aly
Keyword(s):  
Particle Size ◽  
Hydraulic Conductivity ◽  
Physical Properties ◽  
Sandy Soil ◽  
Tap Water ◽  
Soil Layer ◽  
Application Rate ◽  
Saturated Hydraulic Conductivity ◽  
Medium Temperature ◽  
Application Rates

Water management and irrigation conservation in calcareous sandy soil are of significant importance for sustaining agricultural production, especially in arid and semi-arid region that facing scarcity of water resources. The changes in hydro-physical characteristics of calcareous sand soil were investigated after date palm waste-derived biochar application in column trials. Significance of pyrolysis temperature (300 °C, 500 °C, and 700 °C), particle size [<0.5 mm (D0.5), 0.5–1 mm (D1), and 1–2 mm (D2)], and application rate (1%, 2.5%, and 5%) were studied. Variations in infiltration rate, intermittent evaporation, and saturated hydraulic conductivity as a function of aforementioned factors were investigated. After amending the top 10-cm soil layer with different biochar and application rates, the columns were subjected to six wetting and drying cycles by applying 25 cm3 tap water per week over a 6-week period. Overall, biochar application resulted in decreased saturated hydraulic conductivity, while improved cumulative evaporation. Specifically, biochar produced at 300 °C and 500 °C demonstrated 10.2% and 13.3% higher cumulative evaporation, respectively., whereas, biochar produced at 700 °C with 5% application rate resulted in decreased cumulative evaporation. Cumulative evaporation increased by 5.0%, 7.7% and, 7.8% for D0.5, D1 and D2 (mm) on average, respectively, as compared with the untreated soil. Thus, biochar with particle size 0.5–1 mm significantly improved hydro-physical properties when applied at 1%. Generally, using biochar produced at medium temperature and small particle size with appropriate application rates could improve the soil hydro-physical properties.

The effect of application rate of chemical herbicides on weed control and yield in early potatoes

1971 ◽  
Vol 77 (2) ◽  
pp. 243-246
Author(s):  
Maurice Eddowes
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Sandy Loam ◽  
Low Cost ◽  
Application Rate ◽  
Control Treatment ◽  
Application Rates ◽  
Herbicide Mixtures ◽  
Rate Controlled ◽  
Annual Weeds

SummaryIn a series of field experiments from 1966 to 1969, on light sandy loam soils in the West Midlands, comparisons were made between two levels of application of herbicides based on urea, triazine and bipyridil compounds for weed control in early potatoes.Under conditions of adequate nutrient and water supply, the high application rate controlled about 94%, and the low application rate about 88% of the annual weeds. At equivalent application rates, urea compounds and herbicide mixtures containing ureas, gave superior weed control to triazine compounds and herbicide mixtures containing triazines, but the ureas were apparently more phytotoxic to the potatoes.In 1970, comparisons were made between three levels of application of ametryne and monolinuron, high, medium and low and an unsprayed control treatment.The highest yields of potatoes were associated with the low application rates of herbicides from 1966 to 1970.It was concluded that, on these light sandy loam soils, when irrigation is available, relatively low application rates of either monolinuron or ametryne, or mixtures of ureas or of triazines, or mixtures of bipyridils and ureas or triazines could give adequate control of annual weeds in early potatoes at low cost.

scholarly journals Utilização de filtro intermitente de areia como pós-tratamento de esgoto doméstico – estudo da taxa de aplicação superficial

2019 ◽  
Vol 1 (47) ◽  
pp. 95
Author(s):  
Robson Arruda Dos Santos ◽  
Gilson Barbosa Athayde Junior
Keyword(s):  
Low Cost ◽  
Application Rate ◽  
Environmental Benefits ◽  
Sand Filters ◽  
Treatment Unit ◽  
Sand Filter ◽  
Main Research ◽  
Application Rates ◽  
The Impact

<p class="Normal1">This research is the study of surface application rate for intermittent sand filter sizing, with emphasis to its constructive aspect. It is a design parameter set by the NBR 13969/1997 like the relation between the flow of sewage and surface area of a treatment unit. We examined the main research projects that studied the use of sand filter as post-treatment sewage, highlighting the superficial application rates used in these studies, comparing them with the recommendations of the Brazilian standard that deal with it. The results show that the NBR 13969/97 recommends a lower value to those obtained by Brazilian and foreigner researchers, and regarding Brazilian research, the value of the standard (100 L / m².dia) is always below the rates evaluated. Thus, we highlight the need to update the NBR 13969/97, for that would meet the actual demand for building sand filters, reactor treating of low cost of construction and maintenance, and good removal efficiency of organic matter and nitrification . The environmental benefits are indisputabl and the improvement of the quality of the effluent decreases the impact on water bodies and soil.</p>

scholarly journals Limited impact of a top-down approach to improve enhanced recovery programme in French university hospitals: a before-after retrospective survey

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Hakim Harkouk ◽  
Perrine Capmas ◽  
Nawal Derridj ◽  
Anissa Belbachir ◽  
Lionelle Nkam ◽  
...  
Keyword(s):  
Enhanced Recovery ◽  
Application Rate ◽  
University Hospitals ◽  
Top Down ◽  
Enhanced Recovery Programme ◽  
Massive Open Online Course ◽  
Application Rates ◽  
Control Intervention ◽  
Before And After ◽  
Total Knee

Abstract Background Enhanced recovery programme (ERP) after surgery needs development in Assistance Publique Hôpitaux de Paris (APHP). Methods A retrospective before-and-after study was performed in 2015 and 2017 on three surgical models (total knee arthroplasty (TKA), colectomy and hysterectomy) in 17 hospitals including 29 surgical departments. Data were collected in one control intervention (total hip arthroplasty (THA), gastrectomy and ovariectomy). In 2016, Massive Open Online Course on ERP and a day meeting information were developed by APHP. A national update on ERP was also organized by HAS and a regional professional partnership programme was started. Primary outcomes were length of stay (LOS) and complications after surgery. Data on ERP items were collected in the patients’ chart and in anaesthetist and surgeon interview. Seventy percent application rate reflects application of ERP procedure. Results 1321 patient’s files were analysed (812 in 2015 and 509 in 2017). The LOS (mean (SD)) is reduced by 1.6 day for TKA (2015, 8.7 (6.7) versus 7.1 (3.4) in 2017; p<0.001) but stable for colectomy and hysterectomy. Incidence of severe complications after surgery is unchanged in all types of surgical models. For TKA and hysterectomy respectively applied items of ERP (i.e. >70% application) increased respectively from 5 to 7 out of 17 and 16 in 2015 and 2017. For colectomy, they were stable at 6 out of 21 in 2015 and 2017. The mean application rates of ERP items stayed below 50% in all cases in 2017. The LOS was negatively correlated with ERP items’ application when data collected in 2015 and 2017 were analysed together. Conclusion ERP application did not significantly improved between 2015 and 2017 for three surgical models after an institutional information and diffusion of recommendations in 29 surgical departments of seventeen French University hospitals underlining the limit of a top-down approach.

Design and Construction of Low-Cost, Low-Volume Roads in Australia

2003 ◽  
Vol 1819 (1) ◽  
pp. 173-179 ◽  
Author(s):  
Frank Bullen
Keyword(s):  
Rural Areas ◽  
Low Cost ◽  
Material Behavior ◽  
Crushed Rock ◽  
Rural Roads ◽  
Highway Infrastructure ◽  
Operating Environments ◽  
Low Volume Roads ◽  
Low Volume ◽  
Efficient Expansion

Inexpensive roads constructed by using local knowledge of material behavior have been shown to be capable of meeting rural traffic requirements without the need for importation of hard and expensive quarried crushed rock or gravel. In Australia, low-cost, low-volume roads are typically rural roads constructed in a broad range of operating environments, varying from arid to tropical. The areas that contain the longest length of rural roads, however, are arid or semiarid and are often subjected to periods with low levels of precipitation and high levels of evaporation, frequently followed by periods of intense rainfall. Locally available materials for road making may not meet the usual standard road authority requirements for high-quality aggregate and are thus termed “marginal,” “nonstandard,” or even “inferior.” Because these materials are a resource that cannot be ignored, locally derived specifications are formulated for specific materials to allow more efficient expansion and maintenance of road networks in remote rural areas. Many of the subgrades within arid and semiarid areas are sensitive to water ingress and are termed “cracking” or “expansive” clays. The combination of hostile environment, poor subgrade, and marginal construction aggregates means that the engineer must take an entrepreneurial approach when developing the rural road infrastructure. Some of the methods used to develop and maintain a highway infrastructure for remote rural areas in Australia are outlined, with the Western Queensland region used for illustrative purposes.

Pavement Evaluation and Rehabilitation Design Methodology Currently Used on Low-Volume Roads in Southern Africa

2003 ◽  
Vol 1819 (1) ◽  
pp. 343-352 ◽  
Author(s):  
J. A. Grobler ◽  
A. Taute ◽  
I. Joubert
Keyword(s):  
Southern Africa ◽  
Design Methodology ◽  
Low Cost ◽  
Cost Effective ◽  
Past Performance ◽  
The Road ◽  
Low Volume Roads ◽  
Pavement Evaluation ◽  
Wide Range ◽  
Low Volume

A pavement evaluation and rehabilitation design methodology is currently employed in southern Africa on relatively light pavement structures used for low-volume roads. The pavements normally consist of natural gravel materials in most layers and thin bituminous surfacings. When nearing the end of their design lives, they exhibit distresses ranging from minor deformation through aging of the surface to structural cracking and potholes. Rehabilitation options normally involve light stone seals or other inexpensive and cost-effective treatments. The phases of investigation for pavement evaluation and rehabilitation designs start with desk study to establish the history of the road and its past performance from pavement management system outputs. Detailed visual evaluations are then conducted of road features and extent of various forms of distress. These data are presented followed by a decision-making process to select areas for more detailed testing. All the information is used to determine the causes of distress and likely rehabilitation alternatives. Further destructive and nondestructive testing is carried out to predict performance of rehabilitation designs and equivalent annual cost comparisons. Rehabilitation design is also done with use of the dynamic cone penetrometer. Decision criteria are set for use of tests undertaken in the assessments, and test results are evaluated. This procedure normally results in a wide range of rehabilitation options, from application of a diluted emulsion as a surface rejuvenator to more extensive patching and resealing to major rehabilitation and overlays. This process effectively produces cost-effective solutions that maximize limited budgets. It is essential that the road authority be prepared to share the risks of the low-cost options with the designer. In this way benefits of low-cost solutions are realized, whereas, in a limited number of instances, premature distress may have to be repaired under routine maintenance.

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