scholarly journals Fast Evaluation of Caprock Strength Sensitivity to Different CO2 Solutions Using Small Sample Techniques

2021 ◽  
Author(s):  
Laura Edvardsen ◽  
Mohammad H. Bhuiyan ◽  
Pierre R. Cerasi ◽  
Ruben Bjørge
Keyword(s):  
Shear Strength ◽  
Continuous Wave ◽  
Small Sample ◽  
Mineral Dissolution ◽  
Gas Reservoirs ◽  
Fast Evaluation ◽  
Norwegian Sea ◽  
Wave Technique ◽  
Fluid Diffusion ◽  
Insight Into

AbstractThe Draupne shale is a rock formation functioning as overburden for gas reservoirs in the Norwegian Sea and potentially as caprock for future CO2 storage locations as well. In this paper, the Draupne shale was exposed to several fluids: CO2 gas, supercritical CO2, CO2 gas dissolved in brine, supercritical CO2 dissolved in brine, as well as brine and dry air. The motivation for the exposure tests was to investigate whether injected CO2 in a reservoir coming into contact with the caprock could change the caprock’s mechanical properties and increase the risk for leakage of the stored CO2. In addition, a systematic exposure study will provide more insight into the various processes susceptible of altering the shale’s shear strength and acoustic velocity, such as clay hydration, mineral dissolution, and capillary forces. Due to the low permeability of the shale, experiments were conducted on mm-sized disk samples, reducing fluid diffusion into the shale, and allowing for many repeated tests on disks close by in the original core. The punch method, where a small circle is punched out of the shale, was used to assess shear strength, while continuous wave technique was used to assess ultrasonic velocity. Results show that the shale is not noticeably sensitive to CO2, in the sense that no additional weakening is observed in the presence of CO2 as compared to brine exposure. This last weakening effect is probably due to poor matching between pore fluid salinity and exposure brine strength.

In-Plane Asymmetries on the Ge(111)-c(2×8) Surface Mapped with the Scanning Tunneling Microscope

1992 ◽  
Vol 295 ◽  
Author(s):  
P. Molinàs-Mata ◽  
J. Zegenhagen ◽  
M. Böhringer ◽  
N. Takeuchi ◽  
A. Selloni
Keyword(s):  
Local Density ◽  
Experimental Studies ◽  
Surface States ◽  
Small Sample ◽  
Constant Current ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Low Energy Electron ◽  
Tunneling Currents ◽  
Insight Into

AbstractWe report on new experimental studies of the Ge(111)-c(2×8) reconstruction performed with low-energy electron diffraction. (LEED) and scanning tunneling microscopy (STM). Weak quarter-order reflections are present in the c(2 × 8) LEED pattern in agreement with previous observations and results of ab initio calculations. In order to gain insight into the predicted splitting of dangling bond states, we compare constant current topographs (CCT's) performed at high-tunneling currents (40.nA) with first-principles calculations of the local density of states (LDOS) 1Å above the surface adatoms and obtain good qualitative agreement. We finally discuss to what extent the STM CCT's at high tunneling currents (small sample-tip distances (STD)) are sensitive to surface states outside the Г point.

scholarly journals Propiedades psicométricas de la Escala de Interacción en las Clases Dirigidas (EICD)

2016 ◽  
Vol 12 (3) ◽  
pp. 840 ◽  
Author(s):  
Adrián Pastor-Barceló ◽  
Vicente Prado-Gascó ◽  
Pilar Bustillo-Casero
Keyword(s):  
Design Methodology ◽  
Scientific Literature ◽  
Small Sample ◽  
Improve Quality ◽  
Validity And Reliability ◽  
Final Version ◽  
First Time ◽  
To Receive ◽  
Insight Into

Purpose: This research focuses on the construction and validation of a scale designed to assess the quality of the supervised classes: Interaction on Supervised Classes Scale (ISCS).Design/methodology/approach: This is a descriptive correlational study. For the construction of the scale three phases were performed in which different experts assessed the adequacy of the items. Finally, the psychometric properties of the final version were studied in a sample of 314 consumers (69.1% women) aged between 18 and 77 with an average of 39.33 years (SD=12.25).Findings: The scale presents adequate validity and reliability, being a useful tool for measuring the interaction in Supervised Classes.Research limitations/implications: The sampling, non-probabilistic or convenience, have taken the sample of a unique sports facility and the small sample size.Practical implications: The ISCS allows managers to receive better feedback, allowing them to obtain deeper insight into the quality and satisfaction of the service. According to its results, the managers may implement different strategies to improve quality in a key service within sports centers.Originality/value: For the first time the interaction between customers and between customers and employees is evaluated both inside and outside the center, a topic that had not yet been studied in the scientific literature. The scale can be applied to any type of directed activity, and will allow a greater understanding of the quality of service.

Frequency modulated continuous wave technique for referencing and multiplexing intensity based fibre optic sensors

2008 ◽  
Author(s):  
R. A. Perez-Herrera ◽  
D. A. Pereira ◽  
O. Frazão ◽  
J. M. Castro Ferreira ◽  
J. L. Santos ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Fibre Optic ◽  
Wave Technique

scholarly journals Ionic Transport Properties of P2O5-SiO2 Glassy Protonic Composites Doped with Polymer and Inorganic Titanium-based Fillers

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3004
Author(s):  
Maciej Siekierski ◽  
Maja Mroczkowska-Szerszeń ◽  
Rafał Letmanowski ◽  
Dariusz Zabost ◽  
Michał Piszcz ◽  
...  
Keyword(s):  
Transport Properties ◽  
Continuous Wave ◽  
Electrochemical Impedance ◽  
Pore Space ◽  
Poly Vinyl Alcohol ◽  
Proton Mobility ◽  
Polymeric Additives ◽  
Wave Technique ◽  
Poly Ethylene

This paper is focused on the determination of the physicochemical properties of a composite inorganic–organic modified membrane. The electrical conductivity of a family of glassy protonic electrolytes defined by the general formula (P2O5)x(SiO2)y, where x/y is 3/7 are studied by Alternating Current electrochemical impedance spectroscopy (AC EIS) method. The reference glass was doped with polymeric additives—poly(ethylene oxide) (PEO) and poly(vinyl alcohol) (PVA), and additionally with a titanium-oxide-based filler. Special attention was paid to determination of the transport properties of the materials thus modified in relation to the charge transfer phenomena occurring within them. The electrical conductivities of the ‘dry’ material ranged from 10−4 to 10−9 S/cm, whereas for ‘wet’ samples the values were ~10−3 S/cm. The additives also modified the pore space of the samples. The pore distribution and specific surface of the modified glassy systems exhibited variation with changes in electrolyte chemical composition. The mechanical properties of the samples were also examined. The Young’s modulus and Poisson’s ratio were determined by the continuous wave technique (CWT). Based on analysis of the dispersion of the dielectric losses, it was found that the composite samples exhibit mixed-type proton mobility with contributions related to both the bulk of the material and the surface of the pore space.

scholarly journals Hydrochemical Processes and Isotopic Study of Geothermal Springs within Soutpansberg, Limpopo Province, South Africa

2019 ◽  
Vol 9 (8) ◽  
pp. 1688 ◽  
Author(s):  
Olatunde Samod Durowoju ◽  
Mike Butler ◽  
Georges-Ivo Ekosse Ekosse ◽  
John Ogony Odiyo
Keyword(s):  
Ion Exchange ◽  
Mineral Dissolution ◽  
Limpopo Province ◽  
Geochemical Processes ◽  
Ion Chemistry ◽  
Isotopic Study ◽  
Geothermal Springs ◽  
Exchange Processes ◽  
Vital Resource ◽  
Insight Into

Geothermal springs and boreholes within the Soutpansberg Group were sampled and analysed for their major ion chemistry and stable isotope compositions in order to ascertain the possible sources and geochemical processes of the waters. The temperature of the geothermal springs ranges from 41 °C to 49 °C (thermal/hot waters) and 53 °C to 69 °C (scalding/hyperthermal waters). The major water types are Na-Cl and Na-HCO3, which are typical of marine and deep groundwaters influenced by ion-exchange processes. The hydrochemical parameters suggest that thermal gradient, carbonate weathering, mineral dissolution, ion exchange, and evaporation are the main geochemical processes controlling the geothermal springs. The δ18O and δ2H values vary from −5.82‰ to −4.82‰ for δ18O and −33.5‰ to −24.6‰ for δ2H for all the geothermal spring water. The isotopic ranges of the groundwater are relatively smaller and more depleted than those of rainwater (δ2H = −9.8‰ and δ18O = −2.7‰). The δ2H and δ18O signatures reveal a significant infiltration before evaporation. The δ2H and δ18O values further confirm that the waters are of meteoric origin, which implies that modern rainfall is the fundamental component of recharge derived from the infiltration of local precipitation with significant contribution of another type of water in the deeper part of the aquifer. These results provide further insight into this basement aquifer, which is a vital resource for the region.

scholarly journals Radiomics for the Diagnosis and Differentiation of Pancreatic Cystic Lesions

Diagnostics ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 505
Author(s):  
Jorge D. Machicado ◽  
Eugene J. Koay ◽  
Somashekar G. Krishna
Keyword(s):  
Predictive Accuracy ◽  
Quantitative Imaging ◽  
Standard Of Care ◽  
Small Sample ◽  
Cystic Lesions ◽  
Current Standard ◽  
Cross Sectional ◽  
Small Sample Sizes ◽  
Insight Into

Radiomics, also known as quantitative imaging or texture analysis, involves extracting a large number of features traditionally unmeasured in conventional radiological cross-sectional images and converting them into mathematical models. This review describes this approach and its use in the evaluation of pancreatic cystic lesions (PCLs). This discipline has the potential of more accurately assessing, classifying, risk stratifying, and guiding the management of PCLs. Existing studies have provided important insight into the role of radiomics in managing PCLs. Although these studies are limited by the use of retrospective design, single center data, and small sample sizes, radiomic features in combination with clinical data appear to be superior to the current standard of care in differentiating cyst type and in identifying mucinous PCLs with high-grade dysplasia. Combining radiomic features with other novel endoscopic diagnostics, including cyst fluid molecular analysis and confocal endomicroscopy, can potentially optimize the predictive accuracy of these models. There is a need for multicenter prospective studies to elucidate the role of radiomics in the management of PCLs.

scholarly journals Weight-for-Age Percentiles and Experience Impact Youth Wrestling Record over the Course of a Season (P23-010-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Heather Reymunde Wittmer ◽  
Steven Reggie ◽  
Erin O'Hora ◽  
Diane DellaValle
Keyword(s):  
Small Sample ◽  
Future Research ◽  
Hydration Status ◽  
Years Of Experience ◽  
Performance Variables ◽  
Funding Sources ◽  
Significant Difference ◽  
And Performance ◽  
Insight Into ◽  
Weight For Age

Abstract Objectives Youth in weight-classified combat sports may attempt to change body weight to gain performance advantage. Differences between weight-for-age percentiles (WAP) and performance in youth wrestlers remains unknown. The purpose of this retrospective study was to examine the differences in performance between wrestlers above and below the 50th WAP over a wrestling season. Methods Participants included 22 male wrestlers from a team in the Pennsylvania Elementary Wrestling League (8.8 ± 2.1 years of age, 2.3 ± 2.3 years of experience). Retrospective data included age, weight, years of experience, family history, and frequency of wins, losses and forfeits over a 3-month wrestling season. Average WAP were calculated using CDC growth charts and wrestlers were assigned to one of two groups <50 th WAP (n = 10) and >50 th WAP (n = 12). Wrestlers were also categorized into two groups in terms of experience (≤2 years, >2 years). Differences between the two groups in performance variables were examined using ANOVA. Results We observed a significant difference between <50th and >50th WAP groups in total forfeits (0.6 ± 1.0; 2.0 ± 1.5, respectively, P < 0.02). There was an interaction observed between WAP group and years of experience in number of total forfeits (P < 0.132) such that wrestlers with <2 years of experience and <50th WAP experienced fewer total forfeits (0.3 ± 0.8) than those >50th percentile (2.0 ± 1.4). Those with more experience in <50th WAP also had fewer forfeits compared to >50th WAP. A similar interaction was observed between WAP group and years of experience in number of total losses (P < 0.187). Wrestlers with <2 years of experience, and <50th WAP experienced more total losses (4.8 ± 1.5) than wrestlers >50th WAP (2.0 ± 1.4). Those with more experience and <50th WAP experienced fewer losses than those >50th WAP. Conclusions We observed a significant difference in forfeits between average WAP groups and an interaction between experience and WAP groups in losses and forfeits in this small sample. Further research is needed to provide insight into how WAP mayaffect performance in this population. Future research may include a larger population, and variables such as BMI-for-age, hydration status, nutrition, body composition and additional factors that affect both weight and performance. Funding Sources n/a.

New insight into Cm(III) interaction with kaolinite – Influence of mineral dissolution

2012 ◽  
Vol 99 ◽  
pp. 100-109 ◽  
Author(s):  
N. Huittinen ◽  
Th. Rabung ◽  
A. Schnurr ◽  
M. Hakanen ◽  
J. Lehto ◽  
...  
Keyword(s):  
Mineral Dissolution ◽  
Insight Into

Workplace Satisfaction Before and After Move to an Open Plan Office - Including Interactions with Gender and Introversion

2017 ◽  
Vol 61 (1) ◽  
pp. 455-459 ◽  
Author(s):  
Nathan Bos ◽  
Kylie Molinaro ◽  
Alexander Perrone ◽  
Kelly Sharer ◽  
Ariel Greenberg
Keyword(s):  
Ad Hoc ◽  
Additional Data ◽  
Small Sample Size ◽  
Small Sample ◽  
Workplace Satisfaction ◽  
Flexible Support ◽  
Before And After ◽  
Open Plan ◽  
Data Source ◽  
Insight Into

Open plan offices are both popular and controversial. We studied the response of a group moving from shared, but closed offices to an open plan office. The main data source reported here is a workplace satisfaction survey given pre-move, post-move, and to a lab baseline comparison group at the same organization, with some additional data from observations and interviews. Workers moving to the open plan office appreciated the flexible support for collaboration and the space’s appearance. There was lower satisfaction related to space for private concentrated work, temperature control, and ability to have private conversations. There were also some statistical interactions suggesting more positive responses by males and less positive responses by introverts; analysis was limited by small sample size. Observations and interviews gave further insight into open plan “neighborhoods” and the design of ad hoc spaces.

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