scholarly journals A Numerical Approach to Investigate the Impact of Acid-Asphaltene Sludge Formation on Wormholing during Carbonate Acidizing

2021 ◽  
pp. 1-26
Author(s):  
Ilyas Khurshid ◽  
Emad Emad Walid Al Shalabi ◽  
Imran Afgan ◽  
Hazim Al-Attar
Keyword(s):  
High Volume ◽  
Numerical Approach ◽  
High Concentration ◽  
Sludge Formation ◽  
Acid Rock ◽  
Injection Volume ◽  
Flow Equations ◽  
Acid Injection ◽  
Asphaltene Deposition ◽  
The Impact

Abstract Carbonate acidization is the process of creating wormholes by injecting acid to increase reservoir permeability and oil production. Nevertheless, some reservoir oils are problematic with low asphaltene stability, which affects the wormholing process. The interactions between acid, rock, and asphaltene lead to acid-asphaltene sludge formation, which reduces oil productivity and acid injectivity. Neglecting this sludge formation, leads to over predicting the depth of the wormhole penetration. Therefore, a numerical model was developed in this study to provide a better understanding of acid-asphaltene sludge formation effect on wormhole creation and propagation in carbonates. A 1D radial model was developed by coupling fluid flow equations in porous media with asphaltene deposition and acid-asphaltene reactions. Then, the developed model was validated and utilized to investigate the effects of different parameters on wormholing including asphaltene presence, acid injection volume and concentration, formation temperature and porosity, and asphaltene concentration. Results showed that acid injection in carbonates with asphaltenic-oils reduces wormhole penetration from 40% to total pore blockage as opposed to reservoirs without asphaltene deposition. The findings also highlighted that shallow wormhole penetration is more pronounced with high volume of acid injection, high porous formations, less diluted acid, and high concentration of asphaltene. In addition, there is an optimum acid injection volume at which wormhole penetration is high and its infiltration is deep into the formation. This is the first work to discuss modeling of acid-asphaltene sludge formation and subsequent wormhole development in carbonates, which is particularly important for problematic crude oils.

Chemical Composition and Metal Speciation in Porewaters from the Upper Qu’Appelle River Basin, Saskatchewan

1993 ◽  
Vol 28 (1) ◽  
pp. 83-110 ◽  
Author(s):  
Richard E. Farrell ◽  
Jae E. Yang ◽  
P. Ming Huang ◽  
Wen K. Liaw
Keyword(s):  
Amino Acids ◽  
Trace Metal ◽  
River Basin ◽  
Drainage Basin ◽  
Metal Speciation ◽  
Anthropogenic Activities ◽  
High Concentration ◽  
Metal Concentrations ◽  
Carbonate Equilibria ◽  
The Impact

Abstract Porewater samples from the upper Qu’Appelle River basin in Saskatchewan, Canada, were analyzed to obtain metal, inorganic ligand and amino add profiles. These data were used to compute the aqueous speciation of the metals in each porewater using the computer program GEOCHEM-PC. The porewaters were classified as slightly to moderately saline. Metal concentrations reflected both the geology of the drainage basin and the impact of anthropogenic activities. Whereas K and Na were present almost entirely as the free aquo ions, carbonate equilibria dominated the speciation of Ca. Mg and Mn (the predominant metal ligand species were of the type MCO3 (s). MCO30. and MHCO3+). Trace metal concentrations were generally within the ranges reported for non-polluted freshwater systems. Whereas the speciation of the trace metals Cr(III) and Co(II) was dominated by carbonate equilibria, Hg(II)-, Zn(II)- and Fe(II)-speciation was dominated by hydroxy-metal complexes of the type M(OH)+ and M(OH)2°. The speciation of Fe(III) was dominated by Fe(OH)3 (s). In porewaters with high chloride concentrations (> 2 mM), however, significant amounts of Hg(II) were bound as HgCl20 and HgClOH0. The aqueous speciation of Al was dominated by Al(OH)4− and Al2Si2O4(OH)6 (s). Total concentrations of dissolved free amino acids varied from 15.21 to 25.17 umole L−1. The most important metal scavenging amino acids were histidine (due to high stability constants for the metal-histidine complexes) and tryptophan (due to its relatively high concentration in the porewaters. i.e., 5.96 to 7.73 umole L−1). Secondary concentrations of various trace metal-amino add complexes were computed for all the porewaters, but metal-amino acid complexes dominated the speciation of Cu(II) in all the porewaters and Ni(II) in two of the porewaters.

scholarly journals Postharvest Burning of Crop Residues in Home Stoves in a Rural Site of Daejeon, Korea: Its Impact to Atmospheric Carbonaceous Aerosol

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 257
Author(s):  
Jin Sang Jung ◽  
Ji Hwan Kang
Keyword(s):  
Urban Area ◽  
Rural Area ◽  
Crop Residues ◽  
Sampling Period ◽  
Carbonaceous Aerosol ◽  
Rural Site ◽  
Carbonaceous Aerosols ◽  
High Concentration ◽  
Crop Residue Burning ◽  
The Impact

To investigate the impact of burning postharvest crop residues in home stoves, PM2.5 samples (particulate matter with a diameter of <2.5 μm) were collected every 3 h at a rural site in Daejeon, Korea during the postharvest season in 2014. A high concentration of levoglucosan was observed with a peak value of 3.8 µg/m3 during the sampling period. The average mannosan/levoglucosan ratio (0.18) at the rural site during a severe BB episode (levoglucosan > 1 μg/m3) was similar to burnings of pepper stems (0.19) and bean stems (0.18) whereas the average OC/levoglucosan ratio (9.9) was similar to burning of pepper stems (10.0), implying that the severe BB episode was mainly attributed to burning of pepper stems. A very strong correlation was observed between levoglucosan and organic carbon (OC) (R2 = 0.81) during the entire sampling period, suggesting that the emission of organic aerosols at the rural site was strongly associated with the burning of crop residues in home stoves. The average mannosan/levoglucosan ratio (0.17 ± 0.06) in the rural area was similar to that in a nearby urban area in Daejeon (0.16 ± 0.04). It was concluded that crop residue burning in a home stove for space heating is one of the important sources of carbonaceous aerosols not only in a rural area but also in the urban area of Daejeon, Korea during the postharvest season.

The underrepresentation of female participants in studies assessing the impact of high-dose exercise on cardiovascular outcomes: a scoping review

2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
S Pallikadavath ◽  
R Patel ◽  
CL Kemp ◽  
M Hafejee ◽  
N Peckham ◽  
...  
Keyword(s):  
Scoping Review ◽  
High Volume ◽  
Cardiovascular Outcomes ◽  
High Dose ◽  
Funding Sources ◽  
Review Protocol ◽  
The Mean ◽  
The Impact ◽  
Over Time ◽  
Funding Acknowledgements

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Cardiovascular adaptations as a result of exercise conducted at high-intensity and high-volume are often termed the ‘Athlete’s heart’. Studies have shown that these cardiovascular adaptations vary between sexes. It is important that both sexes are well represented in this literature. However, many studies assessing the impact of high-dose exercise on cardiovascular outcomes under-recruit female participants. Purpose This scoping review aimed to evaluate the representation of females in studies assessing the impact of high-dose exercise on cardiovascular outcomes and demonstrate how this has changed over time. Methods The scoping review protocol as outlined by Arksey and O’Malley was used. OVID and EMBASE databases were searched and studies independently reviewed by two reviewers. Studies must have investigated the effects of high-dose exercise on cardiovascular outcomes. To assess how the recruitment of females has changed over time, two methods were used. One, the median study date was used to categorise studies into two groups. Two, studies were divided into deciles to form ten equal groups over the study period. Mean percentage of female recruitment and percentage of studies that failed to include females were calculated. Results Overall, 250 studies were included. Over half the studies (50.8%, n = 127) did not include female participants. Only 3.2% (n = 8) did not include male participants. Overall, mean percentage recruitment was 18.2%. The mean percentage of recruitment was 14.5% before 2011 and 21.8% after 2011. The most recent decile of studies demonstrated the highest mean percentage of female recruitment (29.3%) and lowest number of studies that did not include female participants (26.9%). Conclusion Female participants are significantly underrepresented in studies assessing cardiovascular outcomes caused by high-dose exercise. The most recent studies show that female recruitment may be improving, however, this still falls significantly short for equal representation. Risk factors, progression and management of cardiovascular diseases vary between sexes, hence, translating findings from male dominated data is not appropriate. Future investigators should aim to establish barriers and strategies to optimise fair recruitment. Mean percentage females recruited per study (%) Percentage studies that do not include women (%) Overall (n = 250) 18.2 50.8 (n = 127) Studies before 2011 (n = 121) 14.5 59.5 (n = 72) Studies after 2011 (n = 129) 21.8 42.6 (n = 55) Table 1: Female recruitment characteristics. The year 2011 (median study year) was chosen as this divides all included studies into two equal groups.

scholarly journals A Comparative UAV Forensic Analysis: Static and Live Digital Evidence Traceability Challenges

Drones ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 42
Author(s):  
Fahad E. Salamh ◽  
Umit Karabiyik ◽  
Marcus K. Rogers ◽  
Eric T. Matson
Keyword(s):  
High Volume ◽  
Forensic Analysis ◽  
Digital Evidence ◽  
Incident Response ◽  
Scientific Contribution ◽  
Response Plan ◽  
Technical Challenges ◽  
And Control ◽  
The Impact ◽  
Categorization Model

The raising accessibility of Unmanned Aerial Vehicles (UAVs), colloquially known as drones, is rapidly increasing. Recent studies have discussed challenges that may come in tow with the growing use of this technology. These studies note that in-depth examination is required, especially when addressing challenges that carry a high volume of software data between sensors, actuators, and control commands. This work underlines static and live digital evidence traceability challenges to further enhance the UAV incident response plan. To study the live UAV forensic traceability issues, we apply the `purple-teaming’ exercise on small UAVs while conducting UAV forensic examination to determine technical challenges related to data integrity and repeatability. In addition, this research highlights current static technical challenges that could pose more challenges in justifying the discovered digital evidence. Additionally, this study discusses potential drone anti-forensic techniques and their association with the type of use, environment, attack vector, and level of expertise. To this end, we propose the UAV Kill Chain and categorize the impact and complexity of all highlighted challenges based on the conducted examination and the presented scientific contribution in this work. To the best of our knowledge, there has not been any contribution that incorporates `Purple-Teaming’ tactics to evaluate UAV-related research in cybersecurity and digital forensics. This work also proposes a categorization model that classifies the discovered UAV static and live digital evidence challenges based on their complexity and impact levels

scholarly journals Pharmacologic modulation of 5-fluorouracil by folinic acid and high-dose pyridoxine for treatment of patients with digestive tract carcinomas

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
David Machover ◽  
Wathek Almohamad ◽  
Vincent Castagné ◽  
Christophe Desterke ◽  
Léa Gomez ◽  
...  
Keyword(s):  
Folinic Acid ◽  
Digestive Tract ◽  
Vitamin B6 ◽  
Colorectal Adenocarcinoma ◽  
High Dose ◽  
High Concentration ◽  
Carcinoma Of The Esophagus ◽  
Pancreas Adenocarcinoma ◽  
The Impact ◽  
High Dose Vitamin

AbstractSupplementation of cancer cells exposed to 5-fluorouracil (FUra) and folinic acid (FA) with high concentration pyridoxal 5′-phosphate, the cofactor of vitamin B6, potentiates the cytotoxicity of FUra in a synergistic interaction mode. We report a pilot study in 13 patients with previously untreated advanced carcinoma of the digestive tract to assess the impact of high-dose pyridoxine (PN) on the antitumor activity of regimens comprising FUra and FA. Five patients had colorectal adenocarcinoma (CRC); 5 had pancreas adenocarcinoma (PC); and 3 had squamous cell carcinoma of the esophagus (EC). Patients with CRC and with PC received oxaliplatin, irinotecan, FUra and FA, and patients with EC had paclitaxel, carboplatin, FUra and FA. PN iv from 1000 to 3000 mg/day preceded each administration of FA and FUra. Eleven patients responded. Two patients with CRC attained CRs and 3 had PRs with reduction rates ≥ 78%. Two patients with PC attained CRs, and 2 had PRs with reduction rates ≥ 79%. Responders experienced disappearance of most metastases. Of 3 patients with EC, 2 attained CRs. Median time to attain a response was 3 months. Unexpected toxicity did not occur. Results suggest that high-dose vitamin B6 enhances antitumor potency of regimens comprising FUra and FA.

scholarly journals The Clean pilot study: evaluation of an environmental hygiene intervention bundle in three Tanzanian hospitals

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Giorgia Gon ◽  
Abdunoor M. Kabanywanyi ◽  
Petri Blinkhoff ◽  
Simon Cousens ◽  
Stephanie J. Dancer ◽  
...  
Keyword(s):  
Pilot Study ◽  
Study Design ◽  
Low Income ◽  
High Volume ◽  
Surface Cleaning ◽  
Low Income Countries ◽  
Training Period ◽  
Future Research ◽  
Environmental Hygiene ◽  
The Impact

Abstract Background Healthcare associated infections (HAI) are estimated to affect up to 15% of hospital inpatients in low-income countries (LICs). A critical but often neglected aspect of HAI prevention is basic environmental hygiene, particularly surface cleaning and linen management. TEACH CLEAN is an educational intervention aimed at improving environmental hygiene. We evaluated the effectiveness of this intervention in a pilot study in three high-volume maternity and newborn units in Dar es Salaam, Tanzania. Methods This study design prospectively evaluated the intervention as a whole, and offered a before-and-after comparison of the impact of the main training. We measured changes in microbiological cleanliness [Aerobic Colony Counts (ACC) and presence of Staphylococcus aureus] using dipslides, and physical cleaning action using gel dots. These were analysed with descriptive statistics and logistic regression models. We used qualitative (focus group discussions, in-depth interviews, and semi-structured observation) and quantitative (observation checklist) tools to measure why and how the intervention worked. We describe these findings across the themes of adaptation, fidelity, dose, reach and context. Results Microbiological cleanliness improved during the study period (ACC pre-training: 19%; post-training: 41%). The odds of cleanliness increased on average by 1.33 weekly during the pre-training period (CI = 1.11–1.60), and by 1.08 (CI = 1.03–1.13) during the post-training period. Cleaning action improved only in the pre-training period. Detection of S. aureus on hospital surfaces did not change substantially. The intervention was well received and considered feasible in this context. The major pitfalls in the implementation were the limited number of training sessions at the hospital level and the lack of supportive supervision. A systems barrier to implementation was lack of regular cleaning supplies. Conclusions The evaluation suggests that improvements in microbiological cleanliness are possible using this intervention and can be sustained. Improved microbiological cleanliness is a key step on the pathway to infection prevention in hospitals. Future research should assess whether this bundle is cost-effective in reducing bacterial and viral transmission and infection using a rigorous study design.

scholarly journals Influence of Age on the Technical Wear of Tenement Houses

2020 ◽  
Vol 11 (1) ◽  
pp. 297
Author(s):  
Jarosław Konior ◽  
Marek Sawicki ◽  
Mariusz Szóstak
Keyword(s):  
Residential Buildings ◽  
Residential Building ◽  
Numerical Approach ◽  
Technical Condition ◽  
Visual Methods ◽  
Secondary Importance ◽  
Building Maintenance ◽  
Technical Maintenance ◽  
Traditional Construction ◽  
The Impact

The research presented in the article, which includes methods, models, and conclusions, contains synthetic and analytical model solutions concerning the problems of the technical maintenance and wear of residential buildings with a traditional construction. The cause and effect relationships between the occurrence of damage in the elements of tenement houses (treated as proof of their maintenance conditions), and the size of the technical wear of these elements were determined using a representative and purposefully selected sample of 102 residential buildings erected during the second half of the nineteenth and early twentieth centuries in Wroclaw’s “Downtown” district. Quantitative damage analysis, which was carried out using empirical (visual) methods of assessing the technical condition of a building, indicates the type and size of damage to the building’s elements that are characteristic for the relevant maintenance conditions. Research concerning the cause–effect relationships (“damage–technical wear”) in observed states allows for a numerical approach to the impact of building maintenance conditions on the degree of the technical wear of its components. The maintenance and exploitation conditions determine the degree of the technical wear of the elements of an old residential building. The exploitation condition of these buildings is manifested by damage to elements caused by water and moisture penetration, which is especially important for poorly maintained buildings. The article shows that the age of the elements of an old residential building with a traditional construction is of secondary importance in the process of the intensity of losing its serviceability value. It was calculated that no more than 30% of the damage of building components is explained by the passage of time, and it is therefore not age that determines the course of the technical wear of the elements of the analyzed tenement houses.

scholarly journals Effects of COVID-19 Pandemic on the Treatment of Pancreatic Cancer: A Perspective from Central Europe

2021 ◽  
Vol 38 (2) ◽  
pp. 158-165
Author(s):  
Ilaria Pergolini ◽  
I. Ekin Demir ◽  
Christian Stöss ◽  
Klaus Emmanuel ◽  
Robert Rosenberg ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Cancer Patients ◽  
Central Europe ◽  
Pancreatic Surgery ◽  
Online Survey ◽  
Viral Infections ◽  
High Volume ◽  
Tumor Board ◽  
Standards Of Care ◽  
The Impact

Background: This survey aimed to register changes determined by the COVID-19 pandemic on pancreatic surgery in a specific geographic area (Germany, Austria, and Switzerland) to evaluate the impact of the pandemic and obtain interesting cues for the future. Methods: An online survey was designed using Google Forms focusing on the local impact of the pandemic on pancreatic surgery. The survey was conducted at 2 different time points, during and after the lockdown. Results: Twenty-five respondents (25/56) completed the survey. Many aspects of oncological care have been affected with restrictions and delays: staging, tumor board, treatment selection, postoperative course, adjuvant treatments, outpatient care, and follow-up. Overall, 60% of respondents have prioritized pancreatic cancer patients according to stage, age, and comorbidities, and 40% opted not to operate high-risk patients. However, for 96% of participants, the standards of care were guaranteed. Discussion/Conclusions: The first wave of the COVID-19 pandemic had an important impact on pancreatic cancer surgery in central Europe. Guidelines for prompt interventions and prevention of the spread of viral infections in the surgical environment are needed to avoid a deterioration of care in cancer patients in the event of a second wave or a new pandemic. High-volume centers for pancreatic surgery should be preferred and their activity maintained. Virtual conferences have proven to be efficient during this pandemic and should be implemented in the near future.

scholarly journals Photocrosslinking and photopatterning of magneto-optical nanocomposite sol–gel thin film under deep-UV irradiation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. Bidaud ◽  
D. Berling ◽  
D. Jamon ◽  
E. Gamet ◽  
S. Neveu ◽  
...  
Keyword(s):  
Uv Irradiation ◽  
Cobalt Ferrite ◽  
Sol Gel ◽  
Optical Devices ◽  
High Concentration ◽  
Nanocomposite Thin Films ◽  
Deep Uv ◽  
High Concentrations ◽  
193 Nm ◽  
The Impact

AbstractThis paper is aimed at investigating the process of photocrosslinking under Deep-UV irradiation of nanocomposite thin films doped with cobalt ferrite magnetic nanoparticles (MNPs). This material is composed of a hybrid sol–gel matrix in which MNP can be introduced with high concentrations up to 20 vol%. Deep-UV (193 nm) is not only interesting for high-resolution patterning but we also show an efficient photopolymerization pathway even in the presence of high concentration of MNPs. In this study, we demonstrate that the photocrosslinking is based on the free radical polymerization of the methacrylate functions of the hybrid precursor. This process is initiated by Titanium-oxo clusters. The impact of the nanoparticles on the photopolymerization kinetic and photopatterning is investigated. We finally show that the photosensitive nanocomposite is suitable to obtain micropatterns with sub-micron resolution, with a simple and versatile process, which opens many opportunities for fabrication of miniaturized magneto-optical devices for photonic applications.

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