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1
Carsughi, F., D. Bellmann, J. Kulda, M. Magnani e M. Stefanon. "Absolute Calibration of Small-Angle Neutron Scattering Data of a Double-Crystal Diffractometer". Journal of Applied Crystallography 30, n. 5 (1 ottobre 1997): 857–61. http://dx.doi.org/10.1107/s0021889897001179.
Testo completoAbstract (sommario):
Small-angle neutron scattering (SANS) experiments generally provide the absolute SANS cross sections and this allows quantitative results to be obtained; however, data collected at double-crystal diffractometers are frequently not normalized to absolute cross sections and they are used only for qualitative analysis. In point-geometry diffractometers, the normalization is done by comparing the scattered intensities to those of samples of known cross sections or by measuring the direct-beam intensity; in the double-crystal diffractometer, the incident flux information is contained in the rocking curve measured without a sample and this feature can therefore be used to normalize the scattered intensities to the SANS cross sections. A sample of thickness 1 mm of the Ni-based superalloy UDIMET 520 was analyzed at a double-crystal diffractometer; the SANS cross section obtained by the proposed procedure compares well with the SANS cross section found for similar materials by using conventional point-geometry diffractometers and calibrated by light water.
2
Roos, J. L. "Primary health care psychiatry". South African Journal of Psychiatry 14, n. 1 (1 marzo 2008): 1. http://dx.doi.org/10.4102/sajpsychiatry.v14i1.85.
Testo completoAbstract (sommario):
<div style="left: 73.788px; top: 351.428px; font-size: 15.45px; font-family: sans-serif; transform: scaleX(0.886868);" data-canvas-width="406.22999999999996">Much needs to be done to improve psychiatric care in South</div><div style="left: 73.788px; top: 374.757px; font-size: 15.45px; font-family: sans-serif; transform: scaleX(0.905417);" data-canvas-width="406.16999999999996">Africa. Resources need to be developed, particularly in rural</div><div style="left: 73.788px; top: 398.087px; font-size: 15.45px; font-family: sans-serif; transform: scaleX(0.914111);" data-canvas-width="406.16999999999985">areas, and psychiatric services need to be better integrated</div><div style="left: 73.788px; top: 421.416px; font-size: 15.45px; font-family: sans-serif; transform: scaleX(0.855137);" data-canvas-width="406.2899999999999">into primary health care services. This process will include the</div><div style="left: 73.788px; top: 444.746px; font-size: 15.45px; font-family: sans-serif; transform: scaleX(0.905584);" data-canvas-width="406.24499999999995">intensive training of mental health care workers. If we look at the</div><div style="left: 73.788px; top: 468.075px; font-size: 15.45px; font-family: sans-serif; transform: scaleX(0.893698);" data-canvas-width="406.27500000000015">training of primary care physicians, their rotation during the 2-year</div><div style="left: 73.788px; top: 491.405px; font-size: 15.45px; font-family: sans-serif; transform: scaleX(0.9028);" data-canvas-width="406.21500000000003">internship falls short in psychiatry. It is not seen as a mainstream</div><div style="left: 73.788px; top: 514.734px; font-size: 15.45px; font-family: sans-serif; transform: scaleX(0.886965);" data-canvas-width="406.21500000000015">rotation point like disciplines such as surgery or internal medicine.</div><div style="left: 73.788px; top: 538.064px; font-size: 15.45px; font-family: sans-serif; transform: scaleX(0.921503);" data-canvas-width="406.26000000000005">This fact, as well as a more student-centred approach and</div><div style="left: 73.788px; top: 561.393px; font-size: 15.45px; font-family: sans-serif; transform: scaleX(0.923528);" data-canvas-width="406.26">emphasis on self-learning in medical curricula, make the search</div><div style="left: 73.788px; top: 584.723px; font-size: 15.45px; font-family: sans-serif; transform: scaleX(0.910728);" data-canvas-width="406.20000000000005">for an appropriate prescribed textbook in psychiatry an important</div><div style="left: 73.788px; top: 608.052px; font-size: 15.45px; font-family: sans-serif; transform: scaleX(0.845747);" data-canvas-width="34.14000000000001">issue.</div>
3
Romer, Sara, Claus Urban, Vladimir Lobaskin, Frank Scheffold, Anna Stradner, Joachim Kohlbrecher e Peter Schurtenberger. "Simultaneous light and small-angle neutron scattering on aggregating concentrated colloidal suspensions". Journal of Applied Crystallography 36, n. 1 (21 gennaio 2003): 1–6. http://dx.doi.org/10.1107/s0021889802016291.
Testo completoAbstract (sommario):
A new sample environment has been developed in order to perform light and small-angle neutron scattering (SANS) simultaneously on colloidal systems. The combination of SANS and diffusing wave spectroscopy (DWS) is of particular use in the high-concentration regime. DWS provides information on the local dynamic properties of the individual particles, whereas SANS gives access to the structural properties on similar length scales. The combination of both methods thus allows one to obtain structural and dynamic information over a very large range of length and time scales. Using this new setup, the onset of aggregation and the sol–gel transition in concentrated destabilized polystyrene sphere suspensions have been investigated. At the gel point, a dramatic change of the particle dynamics from diffusion to a subdiffusive arrested motion is observed. However, while the DWS measurements indicate that dramatic changes in the local dynamics occur over a long period, the SANS pattern quickly reaches its final appearance. The SANS experiments thus indicate that a fluid-like structure is arrested in the course of the gel formation. The data are found to be in good qualitative agreement with computer simulations.
4
HOBBIE, E. K., G. MERKLE, B. J. BAUER e C. C. HAN. "SPINODAL DECOMPOSITION IN HYDROGEN-BONDED POLYMER BLENDS". Modern Physics Letters B 10, n. 25 (30 ottobre 1996): 1219–26. http://dx.doi.org/10.1142/s0217984996001383.
Testo completoAbstract (sommario):
Time-resolved small-angle neutron-scattering (SANS) studies of spinodal decomposition in hydrogen-bonded blends of polystyrene and poly(butylmethacrylate) reveal extremely slow kinetics of phase separation in the vicinity of the critical point. The experimental data are interpreted within the context of a mean-field model that predicts energetic barriers to extended composition fluctuations. The scenario bears a resemblance to dynamic critical phenomena in Ising systems with coupling to a set of mobile impurities.
5
Dewhurst, C. D., e I. Grillo. "Neutron imaging using a conventional small-angle neutron scattering instrument". Journal of Applied Crystallography 49, n. 3 (12 aprile 2016): 736–42. http://dx.doi.org/10.1107/s1600576716003940.
Testo completoAbstract (sommario):
Neutron imaging has enjoyed a flurry of activity and application in recent years. The construction of dedicated beamlines at various neutron sources has demonstrated the significant interest among the science and engineering communities, with particular relevance to industrial applications, the nondestructive testing of components and imaging of precious archaeological artefacts. Here two methods are demonstrated of how neutron imaging can be performed using a conventional small-angle neutron scattering (SANS) instrument, such as D33 at the Institut Laue–Langevin, with spatial resolutions down to about 100 µm. The first is a magnified imaging technique from a quasi-point-like source with the magnified image recorded on the usual low-resolution SANS detector. The second method uses a fine beam in a raster-scan measurement over the area of interest. Images can be reconstructed either using the transmitted beam, as in conventional radiographic imaging, or from scattering data, giving access to transmission radiographic images as well as the dark-field or scattering contrasts and phase-contrast images.
6
Balbi, J. H., P. A. Santoni e J. L. Dupuy. "Dynamic modelling of fire spread across a fuel bed". International Journal of Wildland Fire 9, n. 4 (1999): 275. http://dx.doi.org/10.1071/wf00005.
Testo completoAbstract (sommario):
The analysis of laboratory fire experiments led to the development of a reaction-diffusion model for the spread of fire across a fuel bed in windless and slopeless conditions. A method for the determination of coefficients in this model based on the dynamic features of a spreading fire is given. The numerical study of the mathematical problem proposed allows us to predict the rate of spread, the fire front perimeter and the temperature distribution for line-ignition and point-ignition fires. These results are compared with success to experimental data. Furthermore, the model allows us to estimate the acceleration of spread for a point-ignition fire in its initial stage and in the steady-state phase. Résumé Une analyse menée sur des expériences de laboratoires nous a permis de proposer un modèle de réaction-diffussion pour la propagation du feu sans vent et sans pente au travers d’une litière. Une méthode d’identification des coefficients du modèle, à partir des caractéristiques dynamiques de la propagation du feu, est donnée. L’étude numérique du problème mathématique nous permet de prédire la vitesse de propagation, le périmètre du front de feu et la température dans le domaine d’étude pour des allumages en ligne et pour des allumages ponctuels. Ces résultats sont comparés avec succés à des données expérimentales. De plus, nous sommes aussi en mesure de décrire l’accélération du front de feu dans les premiers instants suivant un allumage ponctuel.
7
Koizumi, Satoshi, Satoru Ueda, Takumi Inada, Yohei Noda e Robert A. Robinson. "Microstructure and water distribution in catalysts for polymer electrolyte fuel cells, elucidated by contrast variation small-angle neutron scattering". Journal of Applied Crystallography 52, n. 4 (22 luglio 2019): 791–99. http://dx.doi.org/10.1107/s1600576719008343.
Testo completoAbstract (sommario):
By using small-angle neutron scattering (SANS) reinforced by scanning electron microscopy, the fine structure of catalysts for polymer electrolyte fuel cells has been investigated. The experimental data resulting from contrast variation with mixed light and heavy water (H2O/D2O) are well described by a core–shell model with fluctuations in concentration between water and Nafion. In particular, SANS obtained with the mixed water ratio 30/70, which corresponds to a matching point between mixed water and Nafion, shows a broad scattering maximum, which is attributed to a 5 nm-thick Nafion shell on the surface of the larger carbon particles. After swelling by water, the ionomer layer absorbs water at the 17 wt% level. By changing the H2O/D2O ratio, it was further confirmed that the catalyst with the ionomer exhibits water repellence, whereas the bare catalyst without the ionomer is wetted by water. Because it is very difficult to extract more information, for instance regarding the Pt–Nafion interactions, by means of small-angle scattering, reflectometry and grazing-incidence scattering experiments with neutrons should be attempted on a model catalyst prepared on a flat substrate.
8
Kim, Man-Ho, Jeong-Mann Doh, Seong Chul Han, Keun Hwa Chae, Byung-Yong Yu, Kyung Tae Hong, Andrew Jackson e Lawrence M. Anovitz. "The pore wall structure of porous semi-crystalline anatase TiO2". Journal of Applied Crystallography 44, n. 6 (4 ottobre 2011): 1238–45. http://dx.doi.org/10.1107/s0021889811037447.
Testo completoAbstract (sommario):
The structure of porous TiO2prepared by electrochemical anodization in a fluoride-containing ethylene glycol electrolyte solution was quantitatively studied using small-angle neutron scattering (SANS) and ultra-small-angle neutron scattering (USANS). The cylindrical pores along the coaxial direction were somewhat irregular in shape, were widely distributed in diameter, and seemed to have a broadly pseudo-hexagonal arrangement. The scattering from the pore wall showed a negative deviation from Porod scattering, indicating that the interface between TiO2and the pore was not sharp. A density gradient of around 40–60 Å at the pore wall (i.e.the interface between the pore and the TiO2matrix) was estimated using both constant and semi-sigmoidal interface models. This gradient may be due to the presence of fluorine and carbon partially absorbed by the pore wall from the fluoride-containing electrolyte or to sorbed water molecules on the wall. The neutron contrast-matching point between the TiO2matrix and the pores filled with liquid H2O/D2O mixtures was 51/49%(v/v) H2O/D2O, yielding an estimated mass density of 3.32 g cm−3. The specific surface area of the sample derived from the (U)SANS data was around 939–1003 m2 cm−3(283–302 m2 g−1).
9
Anovitz, Lawrence Michael, David Robert Cole, Julia Meyer Sheets, Alexander Swift, Harold William Elston, Susan Welch, Steve James Chipera, Kenneth Charles Littrell, David Francis Raymond Mildner e Matthew John Wasbrough. "Effects of maturation on multiscale (nanometer to millimeter) porosity in the Eagle Ford Shale". Interpretation 3, n. 3 (1 agosto 2015): SU59—SU70. http://dx.doi.org/10.1190/int-2014-0280.1.
Testo completoAbstract (sommario):
Porosity and permeability are key variables that link the thermal-hydrologic, geomechanical, and geochemical behavior in rock systems and are thus important input parameters for transport models. Neutron scattering studies indicate that the scales of pore sizes in rocks extend over many orders of magnitude from nanometer-sized pores with huge amounts of total surface area to large open fracture systems (multiscale porosity). However, despite considerable efforts combining conventional petrophysics, neutron scattering, and electron microscopy, the quantitative nature of this porosity in tight gas shales, especially at smaller scales and over larger rock volumes, remains largely unknown. Nor is it well understood how pore networks are affected by regional variation in rock composition and properties, thermal changes across the oil window (maturity), and, most critically, hydraulic fracturing. To improve this understanding, we have used a combination of small- and ultrasmall-angle neutron scattering (U)SANS with scanning electron microscope (SEM)/backscattered electron imaging to analyze the pore structure of clay- and carbonate-rich samples of the Eagle Ford Shale. This formation is hydrocarbon rich, straddles the oil window, and is one of the most actively drilled oil and gas targets in the United States. Several important trends in the Eagle Ford rock pore structure have been identified using our approach. The (U)SANS results reflected the connected (effective) and unconnected porosity, as well as the volume occupied by organic material. The latter could be separated using total organic carbon data and, at all maturities, constituted a significant fraction of the apparent porosity. At lower maturities, the pore structure was strongly anisotropic. However, this decreased with increasing maturity, eventually disappearing entirely for carbonate-rich samples. In clay- and carbonate-rich samples, a significant reduction in total porosity occurred at (U)SANS scales, much of it during initial increases in maturity. This apparently contradicted SEM observations that showed increases in intraorganic porosity with increasing maturity. Organic-rich shales are, however, a very complex material from the point of view of scattering studies, and a more detailed analysis is needed to better understand these observations.
10
Taufiq, Ahmad, Sunaryono, Nurul Hidayat, Arif Hidayat, Edy Giri Rachman Putra, Atsushi Okazawa, Isao Watanabe, Norimichi Kojima, Suminar Pratapa e Darminto. "Studies on Nanostructure and Magnetic Behaviors of Mn-Doped Black Iron Oxide Magnetic Fluids Synthesized from Iron Sand". Nano 12, n. 09 (settembre 2017): 1750110. http://dx.doi.org/10.1142/s1793292017501107.
Testo completoAbstract (sommario):
Manganese (Mn)-doped black iron oxide (Fe3O4) magnetic fluids in the system of MnxFe[Formula: see text]O4 were successfully synthesized from natural magnetite (iron sand) by using co-precipitation method at room temperature. The analyses of the small angle neutron scattering (SANS) data by applying a log-normal sphere with a mass fractal models for [Formula: see text] and [Formula: see text] and two log-normal spheres with a single mass fractal models for [Formula: see text], 0.75 and 1 revealed that the primary particles of the MnxFe[Formula: see text]O4 fluids tended to decrease from 3.8[Formula: see text]nm to 1.5[Formula: see text]nm along with the increasing fraction of Mn contents. The fractal dimension ([Formula: see text]) increased from about 1.2 to 2.7 as the Mn contents were increasing; which physically represents an aggregation of the MnxFe[Formula: see text]O4 particles in the fluids growing up from 1 to 3 dimensions to consolidate a more compact structure. The magnetization curves of the fluids exhibited an increasing saturation magnetization from [Formula: see text] to [Formula: see text], and a decreasing on [Formula: see text] and 0.75, with the maximum achievement of [Formula: see text]. These phenomena may probably be due to the combined effects, arising from cationic and dopant distributions, aggregation and its size, and also fractal dimension. Furthermore, the decrease of blocking temperature of the MnxFe[Formula: see text]O4 magnetic fluids could be associated with the reduced particle sizes, while the freezing temperature had its highest peak intensity when it collectively occurred with the blocking temperature at a similar point of about 270[Formula: see text]K.
11
Tafere, Yilkal, Mirkuzie Woldie e Henok Assefa. "Investigations of Latrine Coverage and Associated Factors Among Debretabor Town, Amhara Region North West Ethiopia". International Journal of Public Health Science (IJPHS) 5, n. 2 (1 giugno 2016): 137. http://dx.doi.org/10.11591/ijphs.v5i2.4777.
Testo completoAbstract (sommario):
<span style="color: #000000; font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 10px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">Studies in a number of countries have shown that wherever inappropraite waste disposal morbidity and mortality rates are high. Although latrine coverage is an important indicator for measuring success of the health service program; data on latrine coverage scarce in the study area. Objective: To investigate latrine coverage and associated factors in among households of Debretabor town, Amhara region, Ethiopia.<span> </span></span><span style="color: #000000; font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 10px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">Methods: A community based cross sectional study was conducted in Debretabor town from September 1-30, 2013. A total of 422 households were included in the study using systematic sampling technique. Data were collected using structured questionnaire and analyzed using SPSS version 16.0. Degree of association between independent and dependent variables was assessed with a 95% confidence level and p-value less than 0.05 was used to detect statistical significance. Result: In this study. Ninety three point five percent of households have latrine. Graduated as model family was predictor for availability of latrine (AOR= 3.18,). Income and house ownership were also found to be predictors for availability of latrine (AOR=3.70), (AOR=8.46), respectively. Educational status of respondents was found to be predictors for availability of latrine (AOR= 2.65). Conclusion: latrine coverage was relatively lower from the national target of 100%, still there are households that use open defication. Educational status, house owner shipe, income and graduated as model family were main factors affecting latrine availability. Improving socio economic status of households, provision of continuous advice and technical support at household level on the availability of latrine are recommended.</span>
12
Tafere, Yilkal, Mirkuzie Woldie e Henok Assefa. "Investigations of latrine coverage and associated factors among Debretabor town, Amhara Region North west Ethiopia". International Journal of Public Health Science (IJPHS) 5, n. 2 (1 giugno 2016): 137. http://dx.doi.org/10.11591/.v5i2.4777.
Testo completoAbstract (sommario):
<span style="color: #000000; font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 10px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">Background: Studies in a number of countries have shown that wherever inappropraite waste disposal morbidity and mortality rates are high. Although latrine coverage is an important indicator for measuring success of the health service program; data on latrine coverage scarce in the study area. Objective: To investigate latrine coverage and associated factors in among households of Debretabor town, Amhara region, Ethiopia.<span> </span></span><span style="color: #000000; font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 10px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">Methods: A community based cross sectional study was conducted in Debretabor town from September 1-30, 2013. A total of 422 households were included in the study using systematic sampling technique. Data were collected using structured questionnaire and analyzed using SPSS version 16.0. Degree of association between independent and dependent variables was assessed with a 95% confidence level and p-value less than 0.05 was used to detect statistical significance. Result: In this study. Ninety three point five percent of households have latrine. Graduated as model family was predictor for availability of latrine (AOR= 3.18,). Income and house ownership were also found to be predictors for availability of latrine (AOR=3.70), (AOR=8.46), respectively. Educational status of respondents was found to be predictors for availability of latrine (AOR= 2.65). Conclusion: latrine coverage was relatively lower from the national target of 100%, still there are households that use open defication. Educational status, house owner shipe, income and graduated as model family were main factors affecting latrine availability. Improving socio economic status of households, provision of continuous advice and technical support at household level on the availability of latrine are recommended.</span>
13
Arrighi, Valeria, e Julia S. Higgins. "Local Effects of Ring Topology Observed in Polymer Conformation and Dynamics by Neutron Scattering—A Review". Polymers 12, n. 9 (21 agosto 2020): 1884. http://dx.doi.org/10.3390/polym12091884.
Testo completoAbstract (sommario):
The physical properties of polymers depend on a range of both structural and chemical parameters, and in particular, on molecular topology. Apparently simple changes such as joining chains at a point to form stars or simply joining the two ends to form a ring can profoundly alter molecular conformation and dynamics, and hence properties. Cyclic polymers, as they do not have free ends, represent the simplest model system where reptation is completely suppressed. As a consequence, there exists a considerable literature and several reviews focused on high molecular weight cyclics where long range dynamics described by the reptation model comes into play. However, this is only one area of interest. Consideration of the conformation and dynamics of rings and chains, and of their mixtures, over molecular weights ranging from tens of repeat units up to and beyond the onset of entanglements and in both solution and melts has provided a rich literature for theory and simulation. Experimental work, particularly neutron scattering, has been limited by the difficulty of synthesizing well-characterized ring samples, and deuterated analogues. Here in the context of the broader literature we review investigations of local conformation and dynamics of linear and cyclic polymers, concentrating on poly(dimethyl siloxane) (PDMS) and covering a wide range of generally less high molar masses. Experimental data from small angle neutron scattering (SANS) and quasi-elastic neutron scattering (QENS), including Neutron Spin Echo (NSE), are compared to theory and computational predictions.
14
Jain, Megha, Aishwarya Nagpal e Abhay Jain. "Government Size and Economic Growth: An Empirical Examination of Selected Emerging Economies". South Asian Journal of Macroeconomics and Public Finance 10, n. 1 (25 febbraio 2021): 7–39. http://dx.doi.org/10.1177/2277978720979889.
Testo completoAbstract (sommario):
The current study attempts to examine the linkage between government (public) spending and economic growth in the broader framework of selected South Asian Nations (SANs), BRICS and other emerging nations by using two sets of empirical modelling over the period 2007–2016 by using inverted U-shaped hypothesis, propounded by Armey curve (1995). The first set has employed system GMM technique to explore the presence of the Armey curve hypothesis using the square term of government size, while the second set has used the threshold regression using system GMM panel modelling to investigate the subsequent reversals (tipping point). The key findings signify the existence of an inverted U-shaped relationship for the selected data set of emerging nations and, therefore, support the Armey curve hypothesis. The projected threshold (tipping) levels (as a percentage of GDP) are 24.31% for the government total expenditures (GTotExp), 12.92% for consumption spending (GConExp) and 7.11% for investment spending (GInvExp). It has been observed that a rise in the public spending (size) resulted in a substantial increase (decrease) in the growth rate when the public spending was before (after) the optimal threshold level, indicating a non-monotonic association. The findings of the study also suggest a policy implication that public spending could only be a short-term measure to deal with crises in any nation, but not a long-term solution. JEL Classification: C23, C33, E60, E62, H00, H50, O40, O50
15
Halverson, Jens R. "Seismic expression of the Upper Morrow sands, western Anadarko Basin". GEOPHYSICS 53, n. 3 (marzo 1988): 290–303. http://dx.doi.org/10.1190/1.1442463.
Testo completoAbstract (sommario):
In the western Anadarko Basin, the Lower Pennsylvanian Upper Morrow sands are both a prolific and an elusive exploration target. Initial production from some of these sands can reach well over 1000 barrels of oil per day, and yet an offset well just 350 m away from a good producer can miss the Morrow sand entirely and result in a dry hole. One‐dimensional merged log modeling, two‐ dimensional log interpolation modeling, color seismic inversion processing, and seismic facies mapping techniques have been applied to the Lear and Darden fields, two Upper Morrow sand fields in the Texas Panhandle. Here the Morrow sands reach an isopach thickness of 10 to 15 m at a depth of 2500 to 3000 m. These Morrow sands are within the thin‐bed regime (below the tuning point) so that there is a correlation between the amplitude of the reflection and the thickness of the sand. The velocity and density contrasts of the shales and sands are sufficient to produce a good acoustic impedance contrast, making the sands detectable on seismic data with good signal‐to‐noise ratios. The comparison of geologic isopach mapping and geophysical seismic facies mapping shows an excellent correlation in the delineation of the Upper Morrow sands.
16
Lorenzen, Robert. "Multivariate linear regression of sonic logs on petrophysical logs for detailed reservoir characterization in producing fields". Interpretation 6, n. 3 (1 agosto 2018): T543—T553. http://dx.doi.org/10.1190/int-2018-0030.1.
Testo completoAbstract (sommario):
Many development wells do not have sonic logs recorded, often because of mechanical issues with deviated wellbores or high cost. Consequently, tying development wells to the seismic data covering the field becomes difficult. This issue is magnified in fields where multiple heterogeneous thin sands form thick-stacked pay packages. Multivariate linear regression is a powerful tool to analyze the interdependence of data. Well data from three producing fields in the Balingian Province, offshore Sarawak, Malaysia, are used to calculate parameters relating the recorded sonic-log data to other recorded petrophysical log data. Those parameters are used next to estimate sonic logs from petrophysical log data alone. The petrophysical log data include depth, gamma ray, density, neutron porosity, and resistivity, thus reflecting the natural assumption that the formation velocity is dependent on compaction, lithology, density, pore space, and fluid content. Parameters are calculated separately for coals, gas-filled sands, and the normal shale and sand sequences, giving one set of parameters for each well. The regression is computed at log scale for every depth point. The coefficient of determination between recorded and estimated sonic logs for the same well is up to 0.96. Blind testing is applied to assess the actual reliability of the linear regression by using the parameters from each well in turn to estimate sonic logs for the other wells with only their petrophysical logs. The best set of parameters is obtained from composite wells with tens of thousands of depth points, where the data from several wells are combined. This ensures that there are multiple instances of coal layers and gas-filled sand layers at many depths, thus providing the most representative data set. Interpretation indicates that the synthetic seismic from estimated sonic logs leads to reliable observations regarding sands and coals and their seismic character.
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Wu, Mengmeng, e Jianfeng Wang. "Registration of point cloud data for matching crushed sand particles". Powder Technology 347 (aprile 2019): 227–42. http://dx.doi.org/10.1016/j.powtec.2019.03.001.
Testo completo
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Arief, Hasan Asy'ari, Mansur Arief, Guilin Zhang, Zuxin Liu, Manoj Bhat, Ulf Geir Indahl, Havard Tveite e Ding Zhao. "SAnE: Smart Annotation and Evaluation Tools for Point Cloud Data". IEEE Access 8 (2020): 131848–58. http://dx.doi.org/10.1109/access.2020.3009914.
Testo completo
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Sehah, Sehah, Hartono Hartono, Zaroh Irayani, Urip Nurwijayanto Prabowo, Fajar Apriyanto, Desty Maharani Sagita e Dwi Purnamasari. "Interpretation of 1D-Resistivity Data to Describe the Aquifer Model in the Serayu Watershed Area of Somagede Village, Somagede District, Banyumas Regency". Jurnal Geologi dan Sumberdaya Mineral 22, n. 2 (3 giugno 2021): 89. http://dx.doi.org/10.33332/jgsm.geologi.v22i2.567.
Testo completoAbstract (sommario):
Acquisition of resistivity data using the Schlumberger configuration has been carried out in the Serayu watershed area of Somagede Village, Somagede District, Banyumas Regency. The purpose of this research was to describe a groundwater aquifer model based on the interpretation of 1D-resistivity data. The research results are resistivity logs of subsurface rock distributed over seven sounding points with resistivity values ranging from 2.24-192.78 m. The sounding points are located at positions of 7°31′28.55″ and 109°19′8.65″ (Sch-1) to 7°31′18.79″ and 109°19′21.45″ (Sch-7). The interpretation of the resistivity logs has resulted in a lithology log at each sounding point. Based on the interpretation, the lithology of the research area is composed of topsoil (42.85-85.13 m), sandy clay which partly slightly wet (7.08-17.18m), sandy clay inserted with gravel (22.44-31.70 m), sand, gravel, and pebble, with various consolidated (22.16-192.78m), sand inserted by gravel (6.77m), alternating sandstone and claystone, some of which are alternated with marl and tuff (8.71-21.99m), and sandstones with various porosity (3.25-8.76m). Shallow aquifers are interpreted to exist in sand inserted by gravel layer (13.23-27.67 m) at the sounding point of Sch-2 where the potential is quite good. While deep aquifers are estimated to be present in the sandstone layer with various porosity (> 46.67 m) at all sounding points with very good potential.Keywords: 1D-resistivity, Serayu watershed, resistivity log, aquifer, Somagede Village.
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Katoh, Kazumasa, e Norio Tanaka. "LOCAL MOVEMENTS OF SAND IN THE SURF ZONE". Coastal Engineering Proceedings 1, n. 20 (29 gennaio 1986): 91. http://dx.doi.org/10.9753/icce.v20.91.
Testo completoAbstract (sommario):
The fluorescent sand tracers are injected in a point in the surf zone. Core samples are taken from the sixteen points on the circumference with the time intervals of fifteen minutes for about five hours. At the same time, the horizontal two components of fluid velocities are measured at the injection point by using an electromagnetic currentmeter. The field observations have been carried out three times on two beaches facing to the Pacific Ocean. The relations between the local sand movements and the fluid dynamics are examined on the basis of the data obtained.
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Imam, SM Reza, Norbert R. Morgenstern, Peter K. Robertson e David H. Chan. "A critical-state constitutive model for liquefiable sand". Canadian Geotechnical Journal 42, n. 3 (1 giugno 2005): 830–55. http://dx.doi.org/10.1139/t05-014.
Testo completoAbstract (sommario):
This paper presents a critical-state constitutive model for sands over a wide range of void ratios and consolidation pressures in a triaxial plane. A single set of parameters, including a unique critical-state line reached at large strain, is also used in the model, and differences in behavior in triaxial compression and extension are modeled by accounting for anisotropy at small and medium ranges of strain. The model uses a capped yield surface (YS), which is characterized by its size and shape. Following evidence in past literature, the stress ratio at the peak point of the capped YS of loose sands is approximated by the stress ratio measured at the peak point of their undrained effective stress path. Yielding parameters obtained using this stress ratio are also applied in modeling dense sand behavior and drained loading. These parameters account for the effects of inherent anisotropy, void ratio, and confining pressure on yielding stresses and are readily determined from laboratory tests, but further research is required on their determination from field data. The model accounts for stress-induced and inherent anisotropies, using different parameters, which develop and evolve independently. Emphasis is placed on proper modeling of aspects of loose sand behavior that affect their susceptibility to flow liquefaction.Key words: constitutive modeling, liquefaction, loose sand, critical state, dilatancy, hardening.
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Liu, Yuxi, Yiping Zhu e Mingzhe Wei. "Application of Point Cloud Data Processing in River Regulation". Marine Technology Society Journal 55, n. 2 (1 marzo 2021): 198–204. http://dx.doi.org/10.4031/mtsj.55.2.15.
Testo completoAbstract (sommario):
Abstract Geotextile materials are often used in river regulation projects to cut down sand loss caused by water erosion, to thus ensure a stable and safe river bed. In order to measure the overlap width in the geotextile-laying procedure, we proposed a point processing method for cloud data, which engages point cloud data obtained by 3-D imaging sonar to do automatic measurements. Firstly, random sampling and consensus point cloud segmentation and outer point filtering based on statistical analysis on density were used to extract the upper and lower plane data of the geotextile. Secondly, cluster classification was used to obtain the edge point cloud. Lastly, edge characteristic parameters were extracted by linear fitting, and the overlap width in geotextile laying was calculated. Results show that this measurement scheme is feasible, robust, and accurate enough to meet the requirements in real-life engineering.
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Yunus, Muhammad, e Zahrin F. Syahdinar. "Bearing Capacity Analysis of Bridge Foundation Based on Cone Penetration Test Data and Soil Parameters Data". Logic : Jurnal Rancang Bangun dan Teknologi 19, n. 3 (30 novembre 2019): 145. http://dx.doi.org/10.31940/logic.v19i3.1471.
Testo completoAbstract (sommario):
One that deserves the attention of planners in designing a bridge structure is the design of the substructure. This is due to the fact that the structure below determines the quality and service life of a bridge and at present many cases of bridge structure failures are caused by failures of the substructure in holding the load acting on the bridge The aim of this research to test the characteristics of the soil and calculate bearing capacity of the foundation based cone penetration testing data and soil parameters at the Aifa bridge construction field in Fafurwar District, Teluk Bintuni Regency, West Papua Province. From the results of testing the soil characteristics in the laboratory, the type of soil at point 1 is the type of good to bad graded sand soil (SW-SP) with a water content of 17.72%, specific gravity 2.98, liquid limit (LL) = 16,746% included in the non-plastic category. While the location of point 2 is obtained from good to bad graded sand soil type (SW-SP) with a water content of 28.52%, specific gravity 2.73, liquid limit (LL) = 16.746% including the non-plastic category. To analysis of the calculation of the bearing capacity of the foundation Aifa bridge using data from the sondir test results for point 1 was obtained allowable bearing capacity (Qall) is 4.610,44 kN and for point 2 was obtained allowable bearing capacity (Qall) is 3.598,43 kN. For calculating bearing capacity of the foundation using soil parameter data for point 1 was obtained bearing capacity allowable (Qall) is 2.209,93 kN and for point 2 was obtained allowable bearing capacity (Qall) is 655,41 kN
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Manga, M. M., M. Ibrahim, U. M. Hassan, R. H. Joseph, A. S. Muhammad, M. A. Danimo, O. Ganiyu, A. Versporten e O. O. Oduyebo. "Empirical antibiotherapy as a potential driver of antibiotic resistance: observations from a point prevalence survey of antibiotic consumption and resistance in Gombe, Nigeria". African Journal of Clinical and Experimental Microbiology 22, n. 2 (8 aprile 2021): 273–78. http://dx.doi.org/10.4314/ajcem.v22i2.20.
Testo completoAbstract (sommario):
Background: Empirical use of antibiotics is a standard practice in the treatment of infections worldwide. However, its over utilization without subsequent culture and antibiotic susceptibility testing could be a major driver of resistance.Over reliance on empirical antibiotherapy is common in most developing countries where antibiotic policies and availability or utilization of clinical microbiology laboratory are suboptimal. A standardized approach to point prevalence survey (PPS) on antimicrobial use (AMU) in hospitals was employed to assess the antimicrobial prescribing practices in Federal Teaching Hospital Gombe (FTHG), Nigeria.Methodology: A PPS was conducted in April 2019 at FTHG by recruiting all in-patients present in the hospital on the day of survey. Data obtained from patients’ records included details of the type and indication for antibiotherapy. A customized online application developed by the University of Antwerp (www.global-pps.be) was used for data-entry, validation, analysis and reporting.Results: Of the total 326 patients who were on admission on the day of survey, 70.6% and 73.4% were on at least one antibiotic in adult and paediatric wards respectively. Most commonly used antibiotics include beta lactams such as cephalosporins (29.2%) and penicillins (22.8%), fluoroquinolones (12.4%), aminoglycosides (9.1%) and macrolides (3.4%). Among patients on antibiotics, route of administration was mainly parenteral (71.6%) while 44.8% were on more than one antibiotic. Overall, 91.3% of the antibiotic treatments were empirical with adults, children and neonates accounting for 96.4%, 77.6% and 100.0% respectively. Empirical antibiotic use is also high in medical wards (86.3%), surgical wards (89.9%) and intensive care unit (100.0%).Conclusion: There is predominance and over-reliance on empirical antibiotherapy in our hospital. It further exposes the poor utilization of clinical microbiology laboratory and the potential for development of antibiotic resistance with resultant increase in morbidity/mortality and poor patient safety. There is need for further studies to highlight the dangers of over-reliance on empirical antibiotherapy and herald improvement in development and implementation of antibiotic stewardship programme.
Keywords: Empirical antibiotherapy, antimicrobial resistance, point prevalence survey, antimicrobial stewardship
French title:L'antibiothérapie empirique comme moteur potentiel de la résistance aux antibiotiques: observations d'une enquêteponctuelle de prévalence de la consommation et de la résistance aux antibiotiques à Gombe, au Nigéria
Contexte: L'utilisation empirique d'antibiotiques est une pratique courante dans le traitement des infections dans le monde entier. Cependant, sa surutilisation sans culture ultérieure ni test de sensibilité aux antibiotiques pourrait être un facteur majeur de résistance. Le recours excessif à l'antibiothérapie empirique est courant dans la plupart des pays en développement où les politiques d'antibiotiques et la disponibilité ou l'utilisation du laboratoire de microbiologie clinique sont sous-optimales. Une approche standardisée de l'enquête de prévalence ponctuelle (PPS) sur l'utilisation des antimicrobiens (AMU) dans les hôpitaux a été utilisée pour évaluer les pratiques de prescription d'antimicrobiens au Federal Teaching Hospital Gombe (FTHG), au Nigéria.Méthodologie: Un PPS a été réalisé en avril 2019 au FTHG en recrutant tous les patients hospitalisés présents à l'hôpital le jour de l'enquête. Les données obtenues à partir des dossiers des patients comprenaient des détails sur le type et l’indication de l’antibiothérapie. Une application en ligne personnalisée développée par l'Université d'Anvers (www.global-pps.be) a été utilisée pour la saisie, la validation, l'analyse et le reporting des données.Résultats: Sur les 326 patients au total qui étaient admis le jour de l'enquête, 70,6% et 73,4% prenaient au moins un antibiotique dans les services pour adultes et pédiatriques respectivement. Les antibiotiques les plus couramment utilisés comprennent les bêta-lactamines telles que les céphalosporines (29,2%) et les pénicillines (22,8%), les fluoroquinolones (12,4%), les aminosides (9,1%) et les macrolides (3,4%). Parmi les patients’ sous antibiotiques, la voie d'administration était principalement parentérale (71,6%) tandis que 44,8% prenaient plus d'un antibiotique. Dans l'ensemble, 91,3% des traitements antibiotiques étaient empiriques, les adultes, les enfants et les nouveau-nés représentant respectivement 96,4%, 77,6% et 100,0%. L'utilisation empirique d'antibiotiques est également élevée dans les services médicaux (86,3%), les services chirurgicaux (89,9%) et les unités de soins intensifs (100,0%).Conclusion: Il y a une prédominance et une dépendance excessive à l'antibiothérapie empirique dans notre hôpital. Il expose en outre la mauvaie utilisation du laboratoire de microbiologie clinique et le potentiel de développement d'une résistance aux antibiotiques avec une augmentation résultante de la morbidité/mortalité et une mauvaise sécurité des patients. Des études supplémentaires sont nécessaires pour mettre en évidence les dangers d'une dépendance excessive à l'antibiothérapie empirique et annoncer une amélioration dans le développement et la mise en œuvre d'un programme de gestion des antibiotiques.
Mots clés: antibiothérapie empirique, résistance aux antimicrobiens, enquête ponctuelle de prévalence, gestion des antimicrobiens
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Li, Hui, Luanxiao Zhao, De-Hua Han, Min Sun e Yu Zhang. "Elastic properties of heavy oil sands: Effects of temperature, pressure, and microstructure". GEOPHYSICS 81, n. 4 (luglio 2016): D453—D464. http://dx.doi.org/10.1190/geo2015-0351.1.
Testo completoAbstract (sommario):
We have investigated the elastic properties of heavy oil sands influenced by the multiphase properties of heavy oil itself and the solid matrix with regard to temperature, pressure, and microstructure. To separately identify the role of the heavy oil and solid matrix under specific conditions, we have designed and performed special ultrasonic measurements for the heavy oil and heavy oil-saturated solids artificial samples. The measured data indicate that the viscosity of heavy oil reaches [Formula: see text] at the temperature of glass point, leading the heavy oil to act as a part of a solid frame of the heavy oil sand sample. The heavy oil is likely movable pore fluid accordingly once its viscosity dramatically drops to approximately [Formula: see text] at the temperature of liquid point. The viscosity-induced elastic modulus of heavy oil in turn makes the elastic properties of heavy oil-saturated grain solid sample to be temperature dependent. In addition, the rock physics model suggests that the microstructure of heavy oil sand is transitional; consequently, the solid Gassmann equation underestimates the measured velocities at the low temperature range of the quasisolid phase of heavy oil, whereas overestimates when the temperature exceeds the liquid point. The heavy oil sand sample has a higher modulus and approaches the upper bound due to the stiffer heavy oil itself acting as a rock frame as the temperature decreases. In contrary, heavy oil sand displays a lower modulus and approaches the lower bound when the heavy oil becomes softer as the temperature goes up.
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Yenwongfai, Honore Dzekamelive, Nazmul Haque Mondol, Jan Inge Faleide, Isabelle Lecomte e Johan Leutscher. "Prestack inversion and multiattribute analysis for porosity, shale volume, and sand probability in the Havert Formation of the Goliat field, southwest Barents Sea". Interpretation 5, n. 3 (31 agosto 2017): SL69—SL87. http://dx.doi.org/10.1190/int-2016-0169.1.
Testo completoAbstract (sommario):
An integrated innovative multidisciplinary approach has been used to estimate effective porosity (PHIE), shale volume ([Formula: see text]), and sand probability from prestack angle gathers and petrophysical well logs within the Lower Triassic Havert Formation in the Goliat field, Southwest Barents Sea. A rock-physics feasibility study revealed the optimum petrofacies discriminating ability of extended elastic impedance (EEI) tuned for PHIE and [Formula: see text]. We then combined model-based prestack inversion outputs from a simultaneous inversion and an EEI inversion into a multilinear attribute regression analysis to estimate absolute [Formula: see text] and PHIE seismic attributes. The quality of the [Formula: see text] and PHIE prediction is shown to increase by integrating the EEI inversion in the workflow. Probability distribution functions and a priori petrofacies proportions extracted from the well data are then applied to the [Formula: see text] and PHIE volumes to obtain clean and shaly sand probabilities. A tectonic-controlled point-source depositional model for the Havert Formation sands is then inferred from the extracted sand bodies and the seismic geomorphological character of the different attributes.
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Joshi, R. C., H. D. Sharma e D. G. Sparrow. "Comparison of pile load test methods". Canadian Geotechnical Journal 26, n. 4 (1 novembre 1989): 742–44. http://dx.doi.org/10.1139/t89-086.
Testo completoAbstract (sommario):
Instrumented model piles were loaded to failure using slow-maintained-load, quick-maintained-load, and constant-rate-of-penetration methods of loading. The piles were driven in a prepared dry-sand bed. The applied load, point load, and shaft resistance were measured using load cells and strain gauges, and axial force distribution was determined. Test data indicate that all the three methods give similar ultimate load at failure. Nonetheless, out of the three methods, the slow-maintained-load method of testing piles, which seems to simulate field conditions, gives the largest settlement for the same applied load. The axial force distribution and shaft resistance along the pile were observed to be identical for all the three pile test methods. Key words: model piles, laboratory study, axial loading, test methods, sands, point load, shaft resistance, ultimate load.
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Liu, Shanshan, Yipeng Zhao e Zhiming Wang. "Artificial Intelligence Method for Shear Wave Travel Time Prediction considering Reservoir Geological Continuity". Mathematical Problems in Engineering 2021 (4 marzo 2021): 1–18. http://dx.doi.org/10.1155/2021/5520428.
Testo completoAbstract (sommario):
The existing artificial intelligence model uses single-point logging data as the eigenvalue to predict shear wave travel times (DTS), which does not consider the longitudinal continuity of logging data along the reservoir and lacks the multiwell data processing method. Low prediction accuracy of shear wave travel time affects the accuracy of elastic parameters and results in inaccurate sand production prediction. This paper establishes the shear wave prediction model based on the standardization, normalization, and depth correction of conventional logging data with five artificial intelligence methods (linear regression, random forest, support vector regression, XGBoost, and ANN). The adjacent data points in depth are used as machine learning eigenvalues to improve the practicability of interwell and the accuracy of single-well prediction. The results show that the model built with XGBoost using five points outperforms other models in predicting. The R2 of 0.994 and 0.964 are obtained for the training set and testing set, respectively. Every model considering reservoir vertical geological continuity predicts test set DTS with higher accuracy than single-point prediction. The developed model provides a tool to determine geomechanical parameters and give a preliminary suggestion on the possibility of sand production where shear wave travel times are not available. The implementation of the model provides an economic and reliable alternative for the oil and gas industry.
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Dong, Pinliang, Jisheng Xia, Ruofei Zhong, Zhifang Zhao e Shucheng Tan. "A New Method for Automated Measurement of Sand Dune Migration Based on Multi-Temporal LiDAR-Derived Digital Elevation Models". Remote Sensing 13, n. 16 (6 agosto 2021): 3084. http://dx.doi.org/10.3390/rs13163084.
Testo completoAbstract (sommario):
While remote sensing methods have long been used for coastal and desert sand dune studies, few methods have been developed for the automated measurement of dune migration in large dune fields. To overcome a major limitation of an existing method named “pairs of source and target points (PSTP)”, this paper proposes a toe line tracking (TLT) method for the automated measurement of dune migration rate and direction using multi-temporal digital elevation models (DEM) derived from light detection and ranging (LiDAR) data. Based on a few simple parameters, the TLT method automatically extracts the base level of a dune field and toe lines of individual dunes. The toe line polygons derived from two DEMs are processed using logical operators and other spatial analysis methods implemented in the Python programming language in a geographic information system. By generating thousands of random sampling points along source toe lines, dune migration distances and directions are calculated and saved with the sampling point feature class. The application of the TLT method was demonstrated using multi-temporal LiDAR-derived DEMs for a 9 km by 2.4 km area in the White Sands Dune Field in New Mexico (USA). Dune migration distances and directions for three periods (24 January 2009–26 September 2009, 26 September 2009–6 June 2010, and 24 January 2009–6 January 2010) were calculated. Sensitivity analyses were carried out using different window sizes and toe heights. The results suggest that both PSTP and TLT produce similar sand dune migration rates and directions, but TLT is a more generic method that works for dunes with or without slipfaces that reach the angle of repose.
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Lai, Zejin, Xiaodong Zhao, Rui Tang e Jinhong Yang. "Electrical Conductivity-Based Estimation of Unfrozen Water Content in Saturated Saline Frozen Sand". Advances in Civil Engineering 2021 (4 febbraio 2021): 1–13. http://dx.doi.org/10.1155/2021/8881304.
Testo completoAbstract (sommario):
The salinity of the pore solution is closely associated with the unfrozen water content and can be reflected by variation in electrical conductivity in frozen soils. However, the influence of salinity was not considered in the existing models for estimation of unfrozen water content based on electrical conductivity measurement, and a model considering the effect of salt content was therefore developed to estimate the change of unfrozen water content of saline sands with variation of salt content (0%, 0.2%, and 1%). The unfrozen water content and the electrical resistivity were measured by nuclear magnetic resonance (NRM) and using resistance test equipment under a temperature ranging from 25°C to −15°C, respectively. The results indicated that the model using a cementation exponent expressed by a piecewise function with respect to temperature can produce a reasonable estimation on the content of unfrozen water. There was an essential difference between nonsaline and saline frozen sands in the increase of electrical resistivity due to the different reduction rates of unfrozen water content. The variation of electrical resistivity in nonsaline sand was mainly caused by the decrease of free water when temperature was higher than the freezing point and adsorbed water when temperature was lower than the freezing point, whereas the reduction of free water in two stages was the main reason for the variation of electrical resistivity in saline sand. The results and data obtained provided a basis for further developing a novel approach to measure the unfrozen water content in the field.
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Bijoy, Sourov Datta, Md Yousuf Gazi, SM Mainul Kabir e Badrul Imam. "Geological and Geophysical Observations to Determine the Gas Seepage Source of Titas Gas Field Region, Bangladesh". Journal of the Asiatic Society of Bangladesh, Science 45, n. 1 (18 giugno 2019): 93–109. http://dx.doi.org/10.3329/jasbs.v45i1.46572.
Testo completoAbstract (sommario):
Titas Gas Field, the largest gas field in Bangladesh, has been encountering gas seepages in numerous points at the surface in an area of about 7 sq. km. at the southeastern part of the field since 2006. Gas has been seeping through the water wells, small and large holes in the fields including agricultural lands, in the river and through the cracks in the ground. The present research attempts to point out the source of the gas seepages based on the field studies, wireline log analyses and other available borehole data. A reconnaissance resistivity survey has been carried out around the high seepages area to detect any evidence of shallow subsurface fault. No fault was detected by resistivity survey in the shallow depth in the seepage area and thus fault as a conduit for the seepage could not be confirmed. Primarily, all wells of Titas Well Location (TWL-C) (Titas-06, 08, 09 and 10) were suspected as possible source wells as the surface distribution of seepages generally clusters around TWL-C. Titas-06 and Titas-08 were taken out of suspect list as the gas seepage distributions do not follow well path and cement bonding against reservoir sands including ‘A’ sand in these two wells are also good. Gas seepages follow the well trajectories of Titas-09 and 10 wells but cement bonding against ‘A’ gas sand in Titas-09 also discarded the well as a probable source of the gas seepage. Also, the suggestion that Titas well-03 could be a source of gas seep is also ruled out because of the fact that it is located 3 km away from the seepage area, there is no evidence of any seepage in between the well 3 and the seepage area, and the gas sands are also well protected. The above evidences turned the whole focus onto Titas-10. Gamma ray, resistivity, density, sonic and neutron log signatures recorded initially in the Titas-10 well strongly indicated a major gas sand and has been designated ‘A1’ gas sand. On the basis of various logs including CBL/VDL log it is evident that about 23 meters (3157-3180-meter MD) gas sand at the top which is not protected by cement. It is most likely source of gas seeps in Titas gas field is the gap in the cement protection at the top of A sand in Titas-10 well.
Asiat. Soc. Bangladesh, Sci. 45(1): 93-109, June 2019
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Laužikas, Rimvydas, e Ingrida Vosyliūtė. "Kultūros paveldo ir lituanistinių mokslo duomenų skaitmeninimas Lietuvoje: 2011 metų situacija*". Informacijos mokslai 60 (1 gennaio 2012): 96–115. http://dx.doi.org/10.15388/im.2012.0.1666.
Testo completoAbstract (sommario):
Straipsnyje susipažindinama su 2011 m. atlikto paveldo ir lituanistinių mokslo duomenų skaitmeninimo situacijos Lietuvoje tyrimo svarbiausiais rezultatais: apžvelgiamos, palyginamos esamos sistemos ir skaitmeninančos institucijos; aptariami skaitmeninimą lemiantys aplinkos veiksniai, ištekliai. Straipsnio pabaigoje pateikiamos svarbiausios esamos problemos, diskutuojami jų sprendimo būdai. Tyrimą atliko Vilniaus universiteto Komunikacijos fakultetas, kartu su UAB „IO Projects“ vykdydamas Lietuvos mokslo tarybos finansuojamą projektą „Lituanistinių mokslo tyrimų ir paveldo infrastruktūrų tinklo kūrimas: projektavimo fazė“.Reikšminiai žodžiai: paveldas, lituanistiniai mokslo duomenys, skaitmeninimas Lietuvoje.Digitization of cultural heritage and scientific data of Lithuanian studies in Lithuania: the 2011 situationRimvydas Laužikas, Ingrida Vosyliūtė SummaryThe article presents the main data on the situation with the digitization of heritage and Lithuanian studies scientific data in Lithuania in 2011. The study was carried out at the Faculty of Communication of Vilnius University when implementing the project Development of the National Network of Infrastructure of Lithuanian Studies Scientific Research and Heritage: the Design Phase financed by the Research Council of Lithuania.The digitization of cultural heritage and Lithuanian studies scientific data has been going on in Lithuania for already more than 15 years. During that time, near 100 different information infrastructures have been developed. Most of scientific data are digitized by the Institute of the Lithuanian Language, Institute of Lithuanian Literature and Folklore, Vilnius University, Vytautas Magnus University and Kaunas University of Technology. From the quantitative point of view, the number of IS controlled by a memory institution is less, but this is determined by a higher concentration and level of strategic management in this sector, which is supervised by the Ministry of Culture.The environmental analysis has shown that the strategic priority given to the scientific research of Lithuanian studies, digitization of their scientific data, heritage data and the legal, political, financial, technological, institutional environment in Lithuania are favourable. There is no factor or reason to be singled out for its strongest influence on the development of infrastructures in Lithuania, because their development is determined by the totality of interrelated factors. When assessing systematically, it was established that the creation and development of the network of Lithuanian studies infrastructure would be most greatly influenced by institutional, technological and function distribution factors; legal and administrative factors would influence them less, while the influence of economic and social factors would be the least.An important source of problems in the digitization of heritage and scientific data of Lithuanian studies in Lithuania is the fact that these sciences, scientific institutions and their infrastructures are supervised by the Ministry of Culture and Science, whereas the memory institutions and information infrastructures of the most important sources (heritage) are in the competence of the Ministry of Culture. Therefore, the creation of specialized information systems and databases in research and memory institutions is almost non-coordinated, and the interoperability of created infrastructures is not ensured.In the existing infrastructures of Lithuanian studies scientific research and heritage, the accumulated digital and digitized content has a great social and cultural significance, but it could be accessed and used much more efficiently upon merging the resources stored in different infrastructures into one single network and upon implementing the strategic management tools in the sphere of digitization of scientific data and creation of research infrastructures.Based on the study results, the following prospects for infrastructure development should be singled out: the further development of the created infrastructures in the technological sense as well as in the sense of contents; creation of inter-institutional infrastructures by optimising the resources and avoiding the duplication of activities; promotion of cooperation and networking by decreasing decentralization and the use of general standards. 10.5pt; line-height: 115%; font-family: Calibri, sans-serif;">
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Tesson, Michel, Caroline Labaune, Bernard Gensous e Vincent Delhaye-Prat. "Quaternary compound incised valleys of the Roussillon coast (SE France): correlation of seismic data with core data". Bulletin de la Société Géologique de France 181, n. 2 (1 marzo 2010): 183–96. http://dx.doi.org/10.2113/gssgfbull.181.2.183.
Testo completoAbstract (sommario):
Abstract A detailed study of a Pliocene to Quaternary incised-valley system located under the Roussillon coastal area (Gulf of Lion) is carried out by means of a high-resolution seismic data set (coastal lagoons and adjacent shelf area), drill reports and analysis of a cored drill (Leucate SC1) performed in 2007 on the barrier beach in the North of Leucate lagoon. The lowermost surface (S100/S200), correlated with a pebbles level on the Leucate core SC1 (R0), erosionnally overlies pliocene deposits. It is incised by a thalweg 15 m depth and deepens progressively from the coastal plain to the outer shelf and dips under the Quaternary forced regressive wedges. Above this basal surface, the infilling of the incised valley corresponds to the seismic unit U1. The lower part of U1 shows continuous sub-horizontal reflectors and is correlated (Leucate SC1) to marine muds with levels of mud-supported gravels (body B). The upper part of unit U1 comprises seismic erosional reflectors that are almost amalgamated under the barrier beach. It is correlated on the Leucate well to body C comprising coarse levels (gravels and pebbles) alternating with marine muds (lower part) and marine coarse sands (upper part). The upper part of the unit is dated 12900 cal yr B.P. This unit is interpreted as resulting of successive phases of incision and infilling due to base-level changes during Pleistocene glacial and interglacial periods. Coarse levels of sand and gravel corresponding to river stages and sands and muds shelly levels representing marine stages. The overlying units represent post-glacial late transgressive (S650) and highstand (U660, U661, U662) deposits. This system is a rare example of well preserved compound incised valleys correlated offshore with Quaternary lowstand wedges. By comparison, the incised valleys along the Atlantic coast of France are “simple” incised valleys where only the last episode of incision/infilling is observable. The Quaternary “compound” incised valleys cited in the literature represent examples of the fluvial part of incised systems, whereas the Languedoc-Roussillon incised valleys probably correspond to estuary or embayment, successively reoccupied during the various Quaternary eustatic cycles. Tectonics is the main factor controlling the depositional stratigraphic architecture. The studied area is located at the hinge point between continental uplift and marine subsidence and favoured the preservation of successive phases of erosion/infilling. The geometry of the Pliocene deposits has also an impact on the shape and orientation of the buried paleovalleys.
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Gulati, Jitendra S., Robert R. Stewart e John M. Parkin. "Analyzing three‐component 3D vertical seismic profiling data". GEOPHYSICS 69, n. 2 (marzo 2004): 386–92. http://dx.doi.org/10.1190/1.1707057.
Testo completoAbstract (sommario):
A three‐component 3D vertical seismic profile (VSP) was acquired over the Blackfoot oil field in Alberta, Canada. The VSP survey was recorded simultaneously with a surface seismic program. The objectives of the VSP were to develop recording logistics, data handling, and processing procedures and to determine if the 3D VSP volumes could image the glauconitic sand reservoir of the Blackfoot field. Dynamite shots from the surface seismic survey, which fell within a 2200‐m offset from the recording well, were used in the VSP analysis. The shots were recorded by a string of three‐component borehole receivers that was moved seven times, resulting in a receiver depth range of 400 to 910 m. The borehole data were processed using basic VSP processing techniques that included hodogram analysis, wavefield separation using median filters, and VSP deconvolution. The final P‐P and P‐S image volumes were obtained by VSP common‐depth point and VSP common‐conversion point stacking the upgoing wavefields followed by f‐xy deconvolution. The P‐P and P‐S images from the VSP correlate well with those from the surface seismic survey. Time slices from the VSP also indicate the trend of the sand channel of the Blackfoot field.
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Aigbadon, Godwin, A. U. Okoro, Chuku Una e Ocheli Azuka. "Depositional facies model and reservoir characterization of USANI field 1, Niger delta basin, Nigeria". International Journal of Advanced Geosciences 5, n. 2 (29 giugno 2017): 57. http://dx.doi.org/10.14419/ijag.v5i2.7720.
Testo completoAbstract (sommario):
The 3-D depositional environment was built using seismic data. The depositional facies was used to locate channels with highly theif zones and distribution of various sedimentary facies. The integration core data and the gamma ray log trend from the wells within the studied interval with right boxcar/right bow-shape indicate muddy tidal flat to mixed tidal flat environments. The bell–shaped from the well logs with the core data indicate delta front with mouth bar, the blocky box- car trend from the well logs with the core data indicate tidal point bar with tidal channel fill. The integration of seismic to well log tie display a good tie in the wells across the field. The attribute map from velocity analysis revealed the presence of hydrocarbons in the identified sands (A, B, C, D1, D2, D4, D5). The major faults F1, F2, F3 and F4 with good sealing capacity are responsible for hydrocarbon accumulation in the field. Detailed petro physical analysis of well log data showed that the studied interval are characterized by sand-shale inter-beds. Eight reservoirs were mapped at depth intervals of 2886m to 3533m with their thicknesses ranging from 12m to 407m. Also the Analysis of the petrophysical results showed that porosity of the reservoirs range from 14% to 28 %; permeability range from 245.70 md to 454.7md; water saturation values from 21.65% to 54.50% and hydrocarbon saturation values from 45.50% to 78.50 %. The by-passed hydrocarbons were identified and estimated in low resistivity pay sands D1, D2 at depth of 2884m – 2940m, sand D5 at depth of 3114m – 3126m respectively. The model serve as a basis for establishing facies model in the field.
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Mandal, Amit Kr, Suvamoy Changder, Anirban Sarkar e Narayan C. Debnath. "Architecting Software as a Service for Data Centric Cloud Applications". International Journal of Grid and High Performance Computing 6, n. 1 (gennaio 2014): 77–92. http://dx.doi.org/10.4018/ijghpc.2014010105.
Testo completoAbstract (sommario):
Software as a service (SaaS) is a new software development and deployment paradigm over the cloud. It offers Information Technology services dynamically as “on-demand” basis. The related application data are stored in the data centers managed by the Cloud Service Providers. Many enterprises are facing a major research challenge due to the unavailability of generic cloud architecture for designing, developing and deploying of cloud services. In this paper a flexible architecture for SaaS has been proposed, specifically for data centric cloud applications which may have access to heterogeneous types of databases. The architecture is composed of several layers, which are interacting with each other through the dynamically selected access points of the corresponding layers interfaces. The paper also enlisted the crucial features for SaaS architectural model. Moreover, a detailed comparative study has been done among the proposed SaaS architectural framework and other existing similar proposals based on the listed features.
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Coakley, John P., Allan S. Crowe e Patrice A. Huddart. "Subsurface sediment profiles below Point Pelee: indicators of postglacial evolution in western Lake Erie". Canadian Journal of Earth Sciences 35, n. 1 (1 gennaio 1998): 88–99. http://dx.doi.org/10.1139/e97-090.
Testo completoAbstract (sommario):
An extensive drilling program, undertaken along the western barrier bar at Point Pelee National Park, Ontario, Canada, yielded considerable subsurface sediment data relevant to the nature and lateral geometry of sedimentary units below the Point Pelee foreland. Four major sedimentary units were identified: a basal clay-rich till, a fine-grained glaciolacustrine sand, a medium-grained sand unit (subdivided into a poorly sorted shoreface sand and an aeolian (dune) sand derived from the shoreface sand), and an organic marsh (gyttja) deposit. The present study confirms the existence of a planar, wave-eroded till surface below the southern portion of Point Pelee at an elevation of approximately 164 m asl. Following this low-water period in the basin, lake levels rose abruptly to an elevation several metres above 172 m asl. This resulted in erosion of the upper part of the glaciolacustrine sand during a later period of stable higher lake levels, perhaps coinciding with the Nipissing flood event (about 4000 BP). This resulted in a planar surface at approximately 169.5 m asl. Several radiocarbon dates on basal gyttja from the marsh (averaging 3200 BP) reflect a subsequent drop in levels to about 2-3 m below present levels. Though undated, the initiation of shoreface and dune sand deposition is roughly coeval with the basal marsh deposits.
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Pantelidis, Lysandros, e Elias Gravanis. "Elastic Settlement Analysis of Rigid Rectangular Footings on Sands and Clays". Geosciences 10, n. 12 (4 dicembre 2020): 491. http://dx.doi.org/10.3390/geosciences10120491.
Testo completoAbstract (sommario):
In this paper an elastic settlement analysis method for rigid rectangular footings applicable to both clays and sands is proposed. The proposed method is based on the concept of equivalent shape, where any rectangular footing is suitably replaced by a footing of elliptical shape; the conditions of equal area and equal perimeter are satisfied simultaneously. The case of clay is differentiated from the case of sand using different contact pressure distribution, whilst, additionally, for the sands, the modulus of elasticity increases linearly with depth. The method can conveniently be calibrated against any set of settlement data obtained analytically, experimentally, or numerically; in this respect the authors used values which have been derived analytically from third parties. Among the most interesting findings is that sands produce “settlement x soil modulus/applied pressure” values approximately 10% greater than the respective ones corresponding to clays. Moreover, for large Poisson’s ratio (v) values, the settlement of rigid footings is closer to the settlement corresponding to the corner of the respective flexible footings. As v decreases, the derived settlement of the rigid footing approaches the settlement value corresponding to the characteristic point of the respective flexible footing. Finally, corrections for the net applied pressure, footing rigidity, and non-elastic response of soil under loading are also proposed.
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Wang, Zhiguo, Jinghuai Gao, Xiaolan Lei, Xiaojie Cui e Daxing Wang. "Application of 3D seismic attributes to optimize the placement of horizontal wells within a tight gas sand reservoir, Ordos Basin, China". GEOPHYSICS 81, n. 3 (maggio 2016): B77—B86. http://dx.doi.org/10.1190/geo2015-0244.1.
Testo completoAbstract (sommario):
The Lower Permian Xiashihezi Formation in the Ordos Basin, China, is a quartz-sandstone reservoir with low porosity and low permeability. We have acquired 3D seismic data and well data from 18 vertical and four horizontal wells to indicate the potential of seismic attribute analyses in locating seismic sweet spots for lateral placement of horizontal wells. Using the analytic wavelet transform with a Morse wavelet, the integration of high tuning spectral components, high sweetness and high spectral attenuation helped us to estimate the distribution of gas-bearing tight sands in the Xiashihezi Formation. Our results revealed that the principal target of horizontal drilling and production was gas-bearing massive point bars in the braided river delta setting of the Ordos Basin. The integrated workflow of the seismic attribute analysis contributes to the optimal horizontal well planning by mining and exposing critical geological information of a tight gas sand reservoir from within 3D seismic data.
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Su, Qin, Huahui Zeng, Yancan Tian, Hailiang Li, Lei Lyu e Xiaomei Zhang. "High-resolution seismic processing technique with broadband, wide-azimuth, and high-density seismic data — A case study of thin-sand reservoirs in eastern China". Interpretation 9, n. 3 (7 luglio 2021): T833—T842. http://dx.doi.org/10.1190/int-2020-0107.1.
Testo completoAbstract (sommario):
Seismic processing and interpretation techniques provide important tools for oil and gas exploration in the Songliao Basin in eastern China, which is dominated by terrestrial facies. In the Songliao Basin, a large number of thin-sand reservoirs are widely distributed and they are the primary targets of potential oil and gas exploration and exploitation. An important part of exploration in the Songliao Basin is to accurately describe the distribution of these thin-sand belts and the sand-body shapes. However, the thickness of these thin-sand reservoirs is generally below the resolution of conventional seismic processing. Most reservoirs are thin interbeds of sand and mudstones with strong vertical and lateral variations. This makes it difficult to accurately predict the vertical and horizontal distribution of the thin-sand bodies using conventional seismic processing and interpretation methods. In addition, these lithologic traps are difficult to identify due to the complex controlling factors and distribution characteristics and the strong concealment. These challenges motivate us to improve the seismic data quality to help delineate thin-sand reservoirs. We have used the broadband, wide-azimuth, and high-density integrated seismic exploration technique to help delineate thin reservoirs. We first use field single-point excitation and single-point receiver acquisition to obtain seismic data with wide frequency bands, wide azimuth angles, and high folds, which contain rich geologic information. Next, we perform near-surface Q compensation, viscoelastic prestack time migration, seismic attributes, and seismic waveform indication inversion on the newly acquired seismic data. The 3D case study indicates the benefits of improving the imaging of thin-sand body and the accuracy of inversion and reservoir characterization using our method.
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Gibbs, J. T., e P. L. Bishop. "A method for describing biofilm surface roughness using geostatistical techniques". Water Science and Technology 32, n. 8 (1 ottobre 1995): 91–98. http://dx.doi.org/10.2166/wst.1995.0271.
Testo completoAbstract (sommario):
Biofilm reactors, such as rotating biological contactors (RBCs) and trickling filters, have been used to treat both municipal and industrial waste streams. One fundamental property of biofilms which may affect their performance is surface roughness, or the magnitude of variability in height over the structure's profile. This property has an effect on the rate of diffusion of nutrients into the biofilm for degradation through its influence on the thickness of the concentration boundary layer. The method presented here to quantify the surface characteristics of a biofilm involves the in situ analysis of biofilm surface profile data collected at discrete points. For each point, a microprobe is lowered from some datum above the surface, and the distance down to the biofilm surface is measured at that point. Statistical analysis performed on the data set produces the correlation coefficient between heights on the biofilm surface at various separation intervals. A graph relating the correlation coefficient to the separation interval between heights is constructed from many points to determine the length over which points with low correlation can be collected. A set of nearly independent height data collected at that length interval is then analyzed for mean and standard deviation. The resulting statistics are characteristic of the magnitude of the variability between independent heights on the surface profile, and can be used to compare and contrast the roughness of biofilm surfaces. This method was used to define the roughness of artificial and real biofilm surfaces. Artificial biofilms, which were made from agar roughed with sand paper of varying grit size, were found to have distinct and consistent roughness, as determined by this method. It was useful to compare the standard deviation (roughness) of real biofilms to these values, because the roughness of sand paper is easily observable, and standardized.
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Sahoo, Hiranya, M. Royhan Gani, Nahid D. Gani, Gary J. Hampson, John A. Howell, Joep E. A. Storms, Allard W. Martinius e Simon J. Buckley. "Predictable patterns in stacking and distribution of channelized fluvial sand bodies linked to channel mobility and avulsion processes". Geology 48, n. 9 (1 giugno 2020): 903–7. http://dx.doi.org/10.1130/g47236.1.
Testo completoAbstract (sommario):
Abstract Despite the importance of channel avulsion in constructing fluvial stratigraphy, it is unclear how contrasting avulsion processes are reflected in stratigraphic-stacking patterns of channelized fluvial sand bodies, as a proxy for how river depocenters shifted in time and space. Using an integrated, geospatially referenced, three-dimensional data set that includes outcrop, core, and lidar data, we identify, for the first time in an outcrop study, a predictive relationship between channelized sand body architecture, paleochannel mobility, and stratigraphic-stacking pattern. Single-story sand bodies tend to occur in vertically stacked clusters that are capped by a multilateral sand body, indicating an upward change from a fixed-channel system to a mobile-channel system in each cluster. Vertical sand body stacking in the clusters implies reoccupation of abandoned channels after “local” avulsion. Reoccupational avulsion may reflect channel confinement, location downstream of a nodal avulsion point that maintained its position during development of the sand body cluster, and/or aggradation and progradation of a backwater-mediated channel downstream of a nodal avulsion point. Sand body clusters and additional multilateral sand bodies are laterally offset or isolated from each other, implying compensational stacking due to “regional” switching of a nodal avulsion point to a new, topographically lower site on the floodplain. The predictive links between avulsion mechanisms, channel mobility, and resultant sand body distributions and stacking patterns shown in our findings have important implications for exploring and interpreting spatiotemporal patterns of stratigraphic organization in alluvial basins.
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Smeets, P. W. M. H., e G. J. Medema. "Combined use of microbiological and non-microbiological data to assess treatment efficacy". Water Science and Technology 54, n. 3 (1 agosto 2006): 35–40. http://dx.doi.org/10.2166/wst.2006.445.
Testo completoAbstract (sommario):
The treatment efficacy for reducing Campylobacter concentrations by a drinking water treatment plant was assessed using a stochastic Monte Carlo model. The goal of the study was to reduce uncertainty of the results by combining microbiological and non-microbiological data in an advanced treatment assessment. Combining raw water Campylobacter and E. coli data reduced the uncertainty on raw water (peak) concentrations five-fold. Similar improvement was achieved for rapid sand filtration. Ozone disinfection was modelled based on ozone concentrations, contact time and temperature. Since this data was available, whereas most microbiological analyses at this point were negative, uncertainty was reduced three-fold. The slow sand filtration assessment could not be improved; however, since previous steps contained less uncertainty, this did not increase uncertainty by much. The study showed that using appropriate data for each treatment step can greatly reduce uncertainty in treatment assessment.
44
Xu, Zheng Lai, e Charles E. Pierce. "Looped Sensors to Measure Differential Settlement by Time Domain Reflectometry". Advanced Materials Research 639-640 (gennaio 2013): 1148–54. http://dx.doi.org/10.4028/www.scientific.net/amr.639-640.1148.
Testo completoAbstract (sommario):
Differential ground settlement is a key parameter to be monitored in engineering practices. The common instruments and techniques available for surface and subsurface settlement measuring, such as surface surveying, settlement platforms, extensometer, inclinometers, and so on, provide point-specific measurements. The number of data points obtained by these methods is pre-determined by the number of the measuring points, and hence the spatial resolution of the measuring system is limited. This paper presents the development of a tension-sensitive time domain reflectometry (TDR) sensor and the experimental program to evaluate its performance for monitoring soil settlement. Testing results show that the looped TDR cable is highly sensitive to tension and effective in detecting subsidence zone in sand.
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Kells, J. A., R. Balachandar e K. P. Hagel. "Effect of grain size on local channel scour below a sluice gate". Canadian Journal of Civil Engineering 28, n. 3 (1 giugno 2001): 440–51. http://dx.doi.org/10.1139/l01-012.
Testo completoAbstract (sommario):
In this study, the effect of grain size on the dynamics of local scour processes is discussed in the context of the erosion that takes place downstream from a submerged sluice gate. Four gradations of non-cohesive bed material were used to study the scour process for various tailwater depth and flow rate conditions. The sand gradations included three sizes of uniformly graded sand and a fourth size, which was obtained by mixing the three uniform sands in equal proportions by weight. A total of 36 tests was carried out, each for a period of 24 h. An equilibrium scour condition was not attained over this time period for any of the tests, although a sense of similarity in the bed profiles is observed in the region close to the sluice gate. The present results indicate that the depth and the area of scour are highly dependent on the bed grain size, both increasing as the grain size is reduced. As well, it was found that the tests with a mixed (i.e., graded) sand bed resulted in less scour relative to those in which a uniformly graded sand of similar grain size was used. Moreover, the maximum scour depth increases with increases in the discharge and the tailwater depth. Finally, it was found that the location of the point of maximum scour depth, as measured from the upstream end of the erodible sand bed, moved downstream with an increase in either the discharge or tailwater depth and upstream with an increase in the grain size.Key words: grain size, grain size distribution, local scour, scour dynamics, sluice gate, tailwater depth, video image data acquisition.
46
Sollid, Anders, e Bjørn Ursin. "Scattering‐angle migration of ocean‐bottom seismic data in weakly anisotropic media". GEOPHYSICS 68, n. 2 (marzo 2003): 641–55. http://dx.doi.org/10.1190/1.1567234.
Testo completoAbstract (sommario):
Scattering‐angle migration maps seismic prestack data directly into angle‐dependent reflectivity at the image point. The method automatically accounts for triplicated rayfields and is easily extended to handle anisotropy. We specify scattering‐angle migration integrals for PP and PS ocean‐bottom seismic (OBS) data in 3D and 2.5D elastic media exhibiting weak contrasts and weak anisotropy. The derivation is based on the anisotropic elastic Born‐Kirchhoff‐Helmholtz surface scattering integral. The true‐amplitude weights are chosen such that the amplitude versus angle (AVA) response of the angle gather is equal to the Born scattering coefficient or, alternatively, the linearized reflection coefficient. We implement scattering‐angle migration by shooting a fan of rays from the subsurface point to the acquisition surface, followed by integrating the phase‐ and amplitude‐corrected seismic data over the migration dip at the image point while keeping the scattering‐angle fixed. A dense summation over migration dip only adds a minor additional cost and enhances the coherent signal in the angle gathers. The 2.5D scattering‐angle migration is demonstrated on synthetic data and on real PP and PS data from the North Sea. In the real data example we use a transversely isotropic (TI) background model to obtain depth‐consistent PP and PS images. The aim of the succeeding AVA analysis is to predict the fluid type in the reservoir sand. Specifically, the PS stack maps the contrasts in lithology while being insensitive to the fluid fill. The PP large‐angle stack maps the oil‐filled sand but shows no response in the brine‐filled zones. A comparison to common‐offset Kirchhoff migration demonstrates that, for the same computational cost, scattering‐angle migration provides common image gathers with less noise and fewer artifacts.
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Gita Aristia, Gabriela Amanda, Istiqomah, Nurul Hidayat, Triwikantoro, Malik A. Baqiya e Suminar Pratapa. "Phase Analysis of Natural Silica-Sand-Based Composites as Potential Fuel-Cell Seal Material". Advanced Materials Research 1112 (luglio 2015): 294–98. http://dx.doi.org/10.4028/www.scientific.net/amr.1112.294.
Testo completoAbstract (sommario):
Seal is one of the most important components in fuel cells which is required to bond the cell stacks and prevent mixing of gases in electrodes. Some of the requirements for such components are able to seal several adjacent cell components, which means compatible in thermal expansion coefficient values, and need to be chemically stable in a long-term operation. In this study, the potential use of natural silica sands from Bancar and Sowan in Tuban, East Java, Indonesia was explored, particularly from phase composition point of view. Six batches of samples were collected from both sites. X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD) data from all samples were complementarily used in this study. XRF and XRD data for each sample showed that quartz (SiO2) was the most dominant phase, with estimated Rietveld method-based weight fraction content ranged between 70.1 and 98.7%. The second dominating phase is calcite (CaCO3). According to the results obtained, we found that there is a slightly difference in the value of phases weight fraction due to RIR and Rietveld methods. In this research, PB-01 sands mixed with 17 wt.% magnesia and were calcined at various temperatures. Natural silica-sand-based composite may give promising excellent candidate for seal fuel cell material, because it forms forsterite and enstatite which suit the CTE value of sealant of fuel cell.
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Vender, Ron, Charles Lynde, Martin Gilbert, Vincent Ho, Sheetal Sapra e Melanie Poulin-Costello. "Etanercept Improves Quality of Life Outcomes and Treatment Satisfaction in Patients with Moderate to Severe Plaque Psoriasis in Clinical Practice". Journal of Cutaneous Medicine and Surgery 16, n. 6 (novembre 2012): 407–16. http://dx.doi.org/10.1177/120347541201600609.
Testo completoAbstract (sommario):
Background: Etanercept is well tolerated and effective in moderate to severe psoriasis; however, data on patient-reported outcomes (PROs) in Canadian patients remain limited. Objective: To assess PROs in Canadian patients with moderate to severe psoriasis receiving etanercept in an open-label trial more representative of general clinical practice than traditional research studies. Methods: This 1-year, multicenter, single-arm study enrolled 246 patients. Patients received etanercept 50 mg subcutaneously twice weekly for 3 months and then 50 mg once weekly for 9 months. Primary and safety end points were reported previously. Change from baseline to month 12 for the Dermatology Life Quality Index (DLQI), EuroQoL-5D, and Treatment Satisfaction Questionnaire for Medication (TSQM) are secondary outcomes reported here. Post hoc analyses of PROs are also reported. Results: Mean ± standard deviation (SD) DLQI total score improved from 13.7 ± 6.1 at baseline to 3.9 ± 5.6 at month 12. By month 12, 75% of patients achieved a clinically meaningful improvement in the DLQI (≥ 5-point improvement or a score of 0). Fifty-three to 86% of patients reported improvement or complete improvement in the six DLQI subscales. The mean ± SD EuroQoL-5D total score improved from baseline (0.67 ± 0.25) to month 12 (0.83 ± 0.25). The TSQM scores showed improvement in global satisfaction, effectiveness, and convenience after 3 months. Conclusions: Etanercept was associated with improved PROs and increased treatment satisfaction over 1 year. Contexte: L'étanercept est un médicament bien toléré et efficace dans le traitement du psoriasis modéré ou grave; toutefois, il existe peu de données sur les résultats déclarés par les patients (RDP) au Canada. Objectif: L'étude visait à évaluer les résultats déclarés par les patients souffrant de psoriasis modéré ou grave, au Canada, et recevant de l'étanercept dans le cadre d'un essai mené sans insu et plus représentatif de la pratique clinique générale que les recherches classiques. Méthodes: Il s'agit d'un essai clinique multicentrique, d'une durée de 1 an, comptant un seul groupe et 246 sujets. Les patients ont reçu de l'étanercept, à raison de 50 mg, par voie sous-cutanée, 2 fois par semaine, pendant 3 mois; et puis 50 mg, 1 fois par semaine, pendant 9 mois. Les principaux critères d'évaluation et ceux liés à l'innocuité ont déjà été décrits. Il sera question ici des critères d'évaluation secondaires, plus particulièrement des changements observés entre le début et la fin de l'essai, au 12e mois, et notés au Dermatology Life Quality Index (DLQI), à l'EuroQoL-5D et au Treatment Satisfaction Questionnaire for Medication (TSQM). Nous ferons également état des analyses a posteriori des RDP. Résultats: La moyenne du résultat total plus ou moins l'écart type au DLQI s'est améliorée et est passée de 13.7 ± 6.1 au début à 3.9 ± 5.6 à la fin (12e mois). Au 12e mois, 75% des patients avaient connu une amélioration importante, sur le plan clinique, d'après le DLQI (amélioration de 5 points ou plus, ou résultat de 0). De 53 à 86% des patients ont fait état d'une amélioration partielle ou complète aux six sous-échelles du DLQI. Il en va de même pour la moyenne du résultat total plus ou moins l'écart type à l'EuroQoL-5D, qui s'est améliorée depuis le début (0.67 ± 0.25) jusqu'au 12e mois (0.83 ± 0.25). Enfin, les résultats au TSQM ont révélé une amélioration du degré global de satisfaction, de l'efficacité, et de l'aspect pratique au bout de 3 mois. Conclusions: L'étanercept a été associé à une amélioration des RDP et à une satisfaction accrue à l'égard du traitement, sur une période de 1 an.
49
Sharma, Manuprita, Bidhan Ray, Ramesh Kumar Sahu, Santosh Raman e Rupali Verma Bagga. "A study of prescription pattern in the drug therapy of CSOM at a tertiary care hospital in eastern part of India". International Journal of Otorhinolaryngology and Head and Neck Surgery 3, n. 2 (25 marzo 2017): 188. http://dx.doi.org/10.18203/issn.2454-5929.ijohns20170436.
Testo completoAbstract (sommario):
<p class="abstract"><strong>Background:</strong> <span lang="EN-IN">Chronic suppurative otitis media (CSOM) is a perforated tympanic membrane with persistent drainage from the middle ear (i.e. lasting >6-12 weeks). A prospective study was undertaken to find out the baseline data on the prescribing pattern of drugs in the treatment of chronic suppurative otitis media. </span></p><p class="abstract"><strong>Methods:</strong> A cross-sectional observational study was conducted on 125 patients attending ENT OPD and microbiology laboratory of a tertiary care teaching hospital with ear discharge and other symptoms and signs of CSOM<span lang="EN-IN">. </span></p><p class="abstract"><strong>Results:</strong> Unilateral infection is more common 82 (65.6%) than bilateral and mostly affects lower socio-economic conditions 90 (72 %). The single bacterial isolate was seen in 102 (81.6%) cases. The mixed growth (contamination) was observed in 12 (9.6%) cases, The 11 (8.8%) cases were found sterile. Higher sensitivity (75%- 95%) was observed with cefuroxime (76.6%), piperacillin/tazobactam (78.7%), doxycycline (85.1%), amikacin (89.4%), and moxifloxacin (93.6%). It showed 38.3% sensitivity with ampicillin, 55.3% with ciprofloxacin, and 61.7% with macrolides. Levofloxacin (85.1%) was more sensitive than ciprofloxacin<span lang="EN-IN">. </span></p><p class="abstract"><strong>Conclusions:</strong> Evaluation of microbiological pattern and their antibiotic sensitivity pattern in local area become helpful in prescribing empirical antibiotics for successful treatment of otitis media and thus minimizing its complications and emergence of resistant strains<span lang="EN-IN">.</span></p><p class="abstract" style="margin-bottom: .0001pt;"><strong>Background:</strong> Nasal obstruction is a common cause of marked nasal septal deviation. It is related strongly with hypoxia. Hypoxic conditions increase mean platelet volume levels. Many studies in literature point out that inflammation related to nasal polyp is mostly dependent on eosinophils and their inflammatory products. Beside eosinophils, platelets may have a role in nasal polyp development. Platelets are involved in hemostasis, tissue repairing and inflammation. Recently, mean platelet volume (MPV) was recognized as a simple inflammatory marker in the inflammatory disease<span lang="EN-IN">. </span>This study investigated the relationship of nasal polyps with MPV (mean platelet volume), platelet count and NLR (neutrophil to lymphocyte ratio).</p><p class="abstract" style="margin-bottom: .0001pt;"><strong>Methods:</strong> The cross-sectional observational study we investigated CBC (complete blood count) parameters of the patients that consulted ENT clinic in a tertiary care teaching hospital, Haldia because of nasal polyp. <span style="color: #101010;">About 76 patients and 42 controls were included in this study. In all groups, WBC (white blood cell count), RBC (red blood cell count), RDW (red cell distribution width), platelet count, MPV, PDW (platelet distribution width) and NLR parameters from CBC (complete blood count) were compared between patients and controls</span><span lang="EN-IN">. </span></p><p class="abstract" style="margin-bottom: .0001pt;"><strong>Results:</strong> Mean WBC values were 6.89±1.33×103/μL in patients with NPs, vs. 7.11±2.32×103/μL in the control group. Mean haemoglobin (Hb) values were 13.19±1.34 g/dL in patients with NPs, vs. 14.1±1.67 g/dl in the control group. Mean MPV values were 9.11 ± 1.08 fL in patients with NPs, vs. 8.32±0.53 fL in the control group. Mean PLT values were 232.38 ± 39.97×103/μL in patients with NPs, vs. 271.44±45.14×103 in the control group. MPV was higher in nasal polyp patients, whereas platelet count was higher in controls. The difference was significant for the mean absolute neutrophil, platelet count, and lymphocyte counts, NLR, PDW and MPV values between the study group and the control group<span lang="EN-IN">. </span></p><strong><span style="font-size: 11.0pt; line-height: 115%; font-family: 'Calibri','sans-serif'; mso-fareast-font-family: Calibri; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-IN; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;" lang="EN-IN">Conclusions:</span></strong><span style="font-size: 11.0pt; line-height: 115%; font-family: 'Calibri','sans-serif'; mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-IN; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;" lang="EN-IN">Platelet count and NLR were significantly lower in patients than the controls, whereas MPV was significantly higher in nasal polyp patients</span><span style="font-size: 11.0pt; line-height: 115%; font-family: 'Calibri','sans-serif'; mso-fareast-font-family: Calibri; mso-bidi-font-family: 'Times New Roman'; mso-ansi-language: EN-IN; mso-fareast-language: EN-US; mso-bidi-language: AR-SA; mso-bidi-font-weight: bold;" lang="EN-IN">. </span>
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SOLARI, L., G. SEMINARA, S. LANZONI, M. MARANI e A. RINALDO. "Sand bars in tidal channels Part 2. Tidal meanders". Journal of Fluid Mechanics 451 (25 gennaio 2002): 203–38. http://dx.doi.org/10.1017/s0022112001006565.
Testo completoAbstract (sommario):
Careful analysis of new field observations on the geometry of meandering tidal channels reveals that the values of meander wavelengths as well as curvatures, conveniently scaled by local channel width, fall within a fairly restricted range, suggesting the existence of some mechanistic process controlling meander formation. A three-dimensional model is then proposed to predict flow and bed topography in weakly meandering tidal channels. The analysis is developed for meander wavelengths much smaller than the tidal wavelength and assuming that sediment is transported both as bedload and as suspended load. Both conditions are typically met in nature. Due to the symmetry of the meander pattern investigated, the theory indicates that oscillations associated with the basic flow give rise to symmetric oscillations of the point bar–pool pattern around the locations of maximum curvature. However, no net migration in a tidal cycle is present, at least for periodic tides with zero mean. Suspended load leads both to an enhanced bottom deformation and to a downstream shifting of the position of the point bar. The model then provides the basis of a planimetric instability theory of the type developed for river meanders (Blondeaux & Seminara 1985). Though the available data do not yet allow a detailed quantitative comparison, it is shown that the wavelengths selected by the ‘bend mechanism’ are somewhat larger than those typically encountered in nature. The geomorphology of the process of meander formation in tidal environments is then discussed and, upon comparison with observational evidence, points out the need for various developments of the present model.