scholarly journals CARIBBEAN BEACH-FACE SLOPES AND BEACH EQUILIBRIUM PROFILES

1988 ◽  
Vol 1 (21) ◽  
pp. 120 ◽  
Author(s):  
John D. Boon ◽  
Malcolm O. Green
Keyword(s):  
Objective Measure ◽  
Field Measurements ◽  
The United States ◽  
Gravitational Acceleration ◽  
Sediment Grain Size ◽  
Practical Result ◽  
Average Value ◽  
Caribbean Islands ◽  
Equilibrium Profiles ◽  
Equilibrium Profile

Field measurements performed on two Caribbean islands revealed that two-dimensional nearshore bottom morphology is well represented by Dean's (1977) model of the beach equilibrium profile, h - A xm, where h is depth below mean water level at a distance x offshore and A is a scale factor. For the curvature, m, we obtained an average value of approximately m - 1/2 through least squares curve fitting of observed profile data, yielding a more concave and therefore steeper profile inshore than m — 2/3, the average previously reported by Dean for quartz sand beaches in the United States. Furthermore, an objective measure of beach steepness was found to be A-*-'1", a quantity which utilizes both of Dean's parameters and which may serve as a surrogate for the beach-face slope, tan /3, on highly concave beaches. Reasonable correlations were found between A?-'m and the environmental parameter, H^ /gDT , where H^ is breaker height, D is sediment grain size, T is wave period and g is gravitational acceleration. Improved prediction of Caribbean beach slopes and beach equilibrium profiles is an important practical result.

Equilibrium Profile of Modern Belted Radial Ply Tires: Its Determination and Performance Benefits

2013 ◽  
Vol 41 (2) ◽  
pp. 127-151
Author(s):  
Rudolf F. Bauer
Keyword(s):  
Finite Element ◽  
Aspect Ratio ◽  
Finite Element Methods ◽  
Mathematical Analysis ◽  
Internal Stresses ◽  
Stress Concentrations ◽  
Equilibrium Profiles ◽  
Equilibrium Profile ◽  
And Performance ◽  
Beneficial Property

ABSTRACT The benefits of a tire's equilibrium profile have been suggested by several authors in the published literature, and mathematical procedures were developed that represented well the behavior of bias ply tires. However, for modern belted radial ply tires, and particularly those with a lower aspect ratio, the tire constructions are much more complicated and pose new problems for a mathematical analysis. Solutions to these problems are presented in this paper, and for a modern radial touring tire the equilibrium profile was calculated together with the mold profile to produce such tires. Some construction modifications were then applied to these tires to render their profiles “nonequilibrium.” Finite element methods were used to analyze for stress concentrations and deformations within all tires that did or did not conform to equilibrium profiles. Finally, tires were built and tested to verify the predictions of these analyses. From the analysis of internal stresses and deformations on inflation and loading and from the actual tire tests, the superior durability of tires with an equilibrium profile was established, and hence it is concluded that an equilibrium profile is a beneficial property of modern belted radial ply tires.

Modular Bridge Expansion Joints for Lacey V. Murrow Floating Bridge

1997 ◽  
Vol 1594 (1) ◽  
pp. 163-171 ◽  
Author(s):  
John A. Van Lund ◽  
Mark R. Kaczinski ◽  
Robert J. Dexter
Keyword(s):  
Fatigue Strength ◽  
Fatigue Cracking ◽  
Field Measurements ◽  
The United States ◽  
Limit States ◽  
Expansion Joints ◽  
Lake Washington ◽  
Floating Bridge ◽  
Modular Bridge Expansion Joints ◽  
Washington State Department

The Lacey V. Murrow Bridge (LVM Bridge) is a 2013-m-long floating bridge on Interstate 90 across Lake Washington in Seattle, Washington. Single-support-bar, swivel-joist modular bridge expansion joint systems are located at each end of the bridge between the shore approach spans and the floating pontoons. These joints were designed for 960 mm of longitudinal movement as well as horizontal and vertical rotations caused by wind, wave, temperature, and changes in lake level elevation. A similar joint in an adjacent floating bridge had experienced premature fatigue cracking at welded attachment details because of low fatigue strength. For the LVM Bridge the joint components were fatigue tested and designed by using fatigue limit-states loads, resulting in welded attachment details with improved fatigue strength. In addition, a stiffer center beam and reduced center-beam span lengths produced lower fatigue stress ranges. Joint movements and rotations, fatigue design methodology, results of dynamic analyses, field measurements of the dynamic response, and construction details are described. The total cost of the LVM joints was 1 percent of the final bridge cost. The Washington State Department of Transportation required a 5-year guarantee for the LVM joints. These are the largest modular bridge expansion joints in the United States to be tested and designed for fatigue.

SOME FEATURES OF THE EQUILIBRIUM COASTAL PROFILE FOR DIFFERENT INITIAL BED SLOPES BASED ON MODELLING STUDY

2017 ◽  
Author(s):  
Dmitry Korzinin ◽  
Dmitry Korzinin ◽  
Igor Leontiev ◽  
Igor Leontiev
Keyword(s):  
Time Scales ◽  
Wave Impact ◽  
Grain Sizes ◽  
Equilibrium Profiles ◽  
Equilibrium Profile ◽  
The Mean ◽  
Wave Conditions ◽  
Bed Slope ◽  
Coastal Profile ◽  
Modelling Study

Modelling study of the equilibrium profiles formed on sandy coasts of different bed slopes and grain sizes under the various wave conditions was realized by using the CROSS-P and Xbeach morphodynamic models. A special criterion taking into account a total volume of bed deformations per one hour was suggested to determine the conditions of profile stabilization. For both models the time scales of equilibrium profile formation were found to be the same. However, the deformation magnitudes differed significantly. Bed deformations were computed on the whole profile length over the 200-hours duration of wave impact. It was concluded that both models predict a trend of the bed slope toward a stable value. CROSS-P model shows the widening of accumulative terrace during the profile evolution. The mean slope of the equilibrium profile was found to depend on the initial bed slope.

The wildland - urban interface fire problem - current approaches and research needs

2010 ◽  
Vol 19 (2) ◽  
pp. 238 ◽  
Author(s):  
William E. Mell ◽  
Samuel L. Manzello ◽  
Alexander Maranghides ◽  
David Butry ◽  
Ronald G. Rehm
Keyword(s):  
Wildland Fire ◽  
Fire Suppression ◽  
Economic Cost ◽  
Field Measurements ◽  
The United States ◽  
Test Methods ◽  
Wildland Urban Interface ◽  
Fuel Treatment ◽  
Treatment Techniques ◽  
Exposure Conditions

Wildfires that spread into wildland–urban interface (WUI) communities present significant challenges on several fronts. In the United States, the WUI accounts for a significant portion of wildland fire suppression and wildland fuel treatment costs. Methods to reduce structure losses are focussed on fuel treatments in either wildland fuels or residential fuels. There is a need for a well-characterised, systematic testing of these approaches across a range of community and structure types and fire conditions. Laboratory experiments, field measurements and fire behaviour models can be used to better determine the exposure conditions faced by communities and structures. The outcome of such an effort would be proven fuel treatment techniques for wildland and residential fuels, risk assessment strategies, economic cost analysis models, and test methods with representative exposure conditions for fire-resistant building designs and materials.

scholarly journals High concentrations of coarse particles emitted from a cattle feeding operation

2011 ◽  
Vol 11 (16) ◽  
pp. 8809-8823 ◽  
Author(s):  
N. Hiranuma ◽  
S. D. Brooks ◽  
J. Gramann ◽  
B. W. Auvermann
Keyword(s):  
United States ◽  
Particulate Matter ◽  
Chemical Properties ◽  
Field Measurements ◽  
The United States ◽  
Water Soluble ◽  
Size Distributions ◽  
Cattle Feeding ◽  
High Concentrations ◽  
Organic Particles

Abstract. Housing roughly 10 million head of cattle in the United States alone, open air cattle feedlots represent a significant but poorly constrained source of atmospheric particles. Here we present a comprehensive characterization of physical and chemical properties of particles emitted from a large representative cattle feedlot in the Southwest United States. In the summer of 2008, measurements and samplings were conducted at the upwind and downwind edges of the facility. A series of far-field measurements and samplings was also conducted 3.5 km north of the facility. Two instruments, a GRIMM Sequential Mobility Particle Sizer (SMPS) and a GRIMM Portable Aerosol Spectrometer (PAS), were used to measure particle size distributions over the range of 0.01 to 25 μm diameter. Raman microspectroscopy was used to determine the chemical composition of particles on a single particle basis. Volume size distributions of dust were dominated by coarse mode particles. Twenty-four hour averaged concentrations of PM10 (particulate matter with a diameter of 10 μm or less) were as high as 1200 μg m−3 during the campaign. The primary constituents of the particulate matter were carbonaceous materials, such as humic acid, water soluble organics, and less soluble fatty acids, including stearic acid and tristearin. A significant fraction of the organic particles was present in internal mixtures with salts. Basic characteristics such as size distribution and composition of agricultural aerosols were found to be different than the properties of those found in urban and semi-urban aerosols. Failing to account for such differences may lead to errors in estimates of aerosol effects on local air quality, visibility, and public health.

scholarly journals Determination of the melting temperature, heat of fusion, and purity analysis of different samples of zidovudine (AZT) using DSC

2010 ◽  
Vol 46 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Adriano Antunes Souza Araújo ◽  
Marília dos Santos Bezerra ◽  
Sílvia Storpirtis ◽  
Jivaldo do Rosário Matos
Keyword(s):  
The United States ◽  
Raw Material ◽  
Heat Of Fusion ◽  
Average Value ◽  
Purity Analysis ◽  
Temperature Heat ◽  
Chemical Purity ◽  
Dsc Curves ◽  
States Pharmacopeia

The determination of chemical purity, melting range, and variation of enthalpy in the process of characterizing medicines is one of the principal requirements evaluated in quality control of the pharmaceutical industry. In this study, the method of purity determination using DSC was outlined, as well as the application of this technique for the evaluation of commercial samples of zidovudine (AZT) (raw material) supplied by different laboratories. To this end, samples from six different laboratories (A, B, C, D, E, and F) and the standard reference (R) from the United States Pharmacopeia (USP) were analyzed. The DSC curves were obtained in the temperature range of 25 to 200 ºC under the dynamic atmosphere of N2 (50 mL min-1), heating rate of β=2 ºC min-1, using an Al capsule containing approximately 2 mg of sample material. The results demonstrated that the standard reference presented a proportion of 99.83% whereas the AZT samples presented a variation ranging from 97.59 to 99.54%. In addition, the standard reference was found to present a temperature of onset of melting point of 122.80 °C. Regarding the samples of active agents provided by the different laboratories, a variation ranging from 118.70 to 122.87 °C was measured. In terms of ΔHm, the samples presented an average value of 31.12 kJ mol-1.

scholarly journals Experimental and field verifications of radial gates as flow measurement structures

2021 ◽  
Author(s):  
Hossein Khalili Shayan ◽  
Javad Farhoudi ◽  
Alireza Vatankhah
Keyword(s):  
Field Measurements ◽  
The United States ◽  
Data Series ◽  
Flow Conditions ◽  
Flow Limit ◽  
Before And After ◽  
Energy And Momentum ◽  
Extensive Experimental Data ◽  
Radial Gate ◽  
Discharge Curves

Abstract Radial gates are common structures in irrigation projects. This paper presents some theoretical-based equations for explicit estimation of the discharge from the radial gate under free and submerged flow conditions using Energy and Momentum (E-M) principles. The proposed equations were calibrated using extensive experimental data collected from the literature and this study for three types of radial gates under free and submerged flow conditions. The submergence threshold of radial gates is concluded, based on the concepts of hydraulic jump and the intersection of free and submerged head-discharge curves. The results indicated that the error in estimating the discharge increases under transition ( − 2.5 ≤ Sr% ≤ + 2.5), gate lip (1 < y0/w ≤ 2), and high submerged (yt/y0 ≥ 0.95) flow conditions. However, in these flow limit conditions, the discharge error can be considerably decreased by adjusting the tailwater depth to flow depth just after the gate and using the energy equation for the sections before and after the gate. The efficiency of the proposed methods was evaluated based on the data series from field measurements of radial gates in 29 check structures at irrigation canals in the United States and Iran. The results showed that the discharge could be estimated using the proposed equations in field conditions with acceptable accuracy.

scholarly journals First Report of Tar Spot on Orange Geiger, Cordia sebestena, Caused by Diatractium cordianum in Florida

Plant Disease ◽  
2008 ◽  
Vol 92 (8) ◽  
pp. 1250-1250 ◽  
Author(s):  
A. J. Palmateer ◽  
J. M. Pérez ◽  
R. A. Cating ◽  
R. C. Ploetz ◽  
M. A. Hoy
Keyword(s):  
Host Record ◽  
The United States ◽  
South Florida ◽  
Fluorescent Light ◽  
New Host ◽  
5.8S Rdna ◽  
Caribbean Islands ◽  
New Host Record ◽  
Tar Spot ◽  
Water Saturated

In July 2007, tar spot symptoms were observed on the leaves of orange Geiger, Cordia sebestena L. (Boraginaceae), in the landscape and a commercial nursery in Homestead, FL. The disease appears to be spreading and is locally severe. Symptoms were circular, slightly hypertrophied spots approximately 5 to 8 cm in diameter, which were slightly chlorotic on the abaxial surface and had numerous circular blackened stroma, 0.2 to 0.4 mm in diameter, on the adaxial surface. As leaves aged and yellowed, the areas around the spots remained pale green. Embedded in the stroma were numerous perithecia, 173 to 312 μm in diameter, circular to irregular in shape, with lateral necks as much as 200 μm long and 73 to 104 μm in diameter. Asci, 77 to 92 × 11 to 13 μm, contained elongate, two-celled ascospores, 50 to 61 × 3 to 5 μm that had a conspicuous constriction at the dividing cell wall. These dimensions and the pathogen's appearance matched closely with those published for Diatractium cordianum (Ellis & Kelsey) Syd (1). Young, symptomless leaves of C. sebestena were sprayed to runoff with a suspension of ascospores approximately 104 ml–1 that were harvested from affected leaves. Inoculated leaves were placed on water-saturated paper towels in petri plates and maintained in a growth chamber at 25°C with fluorescent light at 10 h day–1. Symptoms similar to those observed on affected trees in the landscape began to develop after 21 days and perithecia were evident after 28 days. An ITS 1, ITS 2, and 5.8s rDNA sequence was deposited in GenBank (Accession No. EU541488). A herbarium specimen was deposited at the U.S. National Fungus Collections (BPI No. 878441). This is a new host record for D. cordianum and is the first time the pathogen has been reported in the United States. Previous records were from Venezuela and several Caribbean islands, including Cuba and Jamaica. Symptoms of this disease have not been observed on Texas wild olive, Cordia boissieri, in close proximity to affected C. sebestena. P. F. Cannon (1) indicated that the disease had no economic impact. However, the conspicuous nature of symptoms on C. sebestena and the importance of this tree in the South Florida ornamental trade (2) suggest that this disease may become significant on the latter host. References: (1) P. F. Cannon. Mycol. Res. 92:327, 1989. (2) E. F. Gilman and D. G. Watson. Fact Sheet ST-182. Univ. Fla, Fla Coop Ext. Serv., 1993.

scholarly journals COMPARING ATMOSPHERIC CORRECTION METHODS FOR LANDSAT OLI DATA

2017 ◽  
Vol 13 (2) ◽  
pp. 105 ◽  
Author(s):  
Esthi Kurnia Dewi ◽  
Bambang Trisakti
Keyword(s):  
Land Cover ◽  
Atmospheric Correction ◽  
Time Consistency ◽  
The United States ◽  
Correction Method ◽  
Visual Observation ◽  
United States Geological Survey ◽  
Spectral Pattern ◽  
Average Value ◽  
Spectral Patterns

Landsat data used for monitoring activities to land cover because it has spatial resolution and high temporal. To monitor land cover changes in an area, atmospheric correction is needed to be performed in order to obtain data with precise digital value picturing current condition. This study compared atmospheric correction methods namely Quick Atmospheric Correction (QUAC), Dark Object Subtraction (DOS) and Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH). The correction results then were compared to Surface Reflectance (SR) imagery data obtained from the United States Geological Survey (USGS) satelite. The three atmospheric correction methods were applied to Landsat OLI data path/row126/62 for 3 particular dates. Then, sample on vegetation, soil and bodies of water (waterbody) were retrieved from the image. Atmospheric correction results were visually observed and compared with SR sample on the absolute value, object spectral patterns, as well as location and time consistency. Visual observation indicates that there was a contrast change on images that had been corrected by using FLAASH method compared to SR, which mean that the atmospheric correction method was quite effective. Analysis on the object spectral pattern, soil, vegetation and waterbody of images corrected by using FLAASH method showed that it was not good enough eventhough the reflectant value differed greatly to SR image. This might be caused by certain variables of aerosol and atmospheric models used in Indonesia. QUAC and DOS made more appropriate spectral pattern of vegetation and water body than spectral library. In terms of average value and deviation difference, spectral patterns of soil corrected by using DOS was more compatible than QUAC.

Use of Laboratory and Field Data to Evaluate the Pier Scour Equation from Hydraulic Engineering Circular 18

2017 ◽  
Vol 2638 (1) ◽  
pp. 113-121
Author(s):  
Stephen T. Benedict ◽  
Thomas P. Knight
Keyword(s):  
South Carolina ◽  
Field Data ◽  
Field Measurements ◽  
The United States ◽  
Prediction Equation ◽  
Hydraulic Engineering ◽  
Bridge Engineering ◽  
Geological Survey ◽  
Pier Scour ◽  
Primary Focus

The Hydraulic Engineering Circular 18 (HEC-18) pier scour prediction equation is the most widely used pier scour prediction equation in the United States, if not the world, and understanding the equation’s performance is of interest to the bridge engineering community. Previous evaluations of the equation’s performance were limited to smaller sets of laboratory and field data. In 2014, the U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, published a U.S. Geological Survey pier scour database, consisting of 569 laboratory and 1,858 field measurements of pier scour. This extensive database is a valuable resource for evaluating the HEC-18 pier scour equation, which is the primary focus of the investigation presented in this paper. Although comparing predicted and measured values is a common method for evaluating the performance of a prediction equation, the present investigation used a different approach and evaluated the HEC-18 equation by comparing selected data from the USGS database with the dimensionless relationship used to develop the original equation. This alternative approach highlighted some of the strengths and weaknesses of the equation, which are not as evident in the more common approach of comparing predicted and measured values. The findings of the investigation are presented in this paper.

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