scholarly journals Petrographic Record and Conditions of Expansive Hydration of Anhydrite in the Recent Weathering Zone at the Abandoned Dingwall Gypsum Quarry, Nova Scotia, Canada

Minerals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 58
Author(s):  
Adrian Jarzyna ◽  
Maciej Bąbel ◽  
Damian Ługowski ◽  
Firouz Vladi
Keyword(s):  
Surface Layer ◽  
Nova Scotia ◽  
Raw Material ◽  
Water Access ◽  
Volume Increase ◽  
Crystallization Pressure ◽  
Confined Environment ◽  
Weathering Zone ◽  
Main Factor

In the Dingwall gypsum quarry in Nova Scotia, Canada, operating in 1933–1955, the bedrock anhydrite deposits of the Carboniferous Windsor Group have been uncovered from beneath the secondary gypsum beds of the extracted raw material. The anhydrite has been subjected to weathering undergoing hydration (gypsification), transforming into secondary gypsum due to contact with water of meteoric derivation. The ongoing gypsification is associated with a volume increase and deformation of the quarry bottom. The surface layer of the rocks is locally split from the substrate and raised, forming spectacular hydration relief. It shows numerous domes, ridges and tepee structures with empty internal chambers, some of which represent unique hydration caves (swelling caves, Quellungshöhlen). The petrographic structure of the weathering zone has been revealed by macro- and microscopic observations. It was recognized that gypsification commonly starts from a developing network of tiny fractures penetrating massive anhydrite. The gypsification advances from the fractures towards the interior of the anhydrite rocks, which are subdivided into blocks or nodules similar to corestones. Characteristic zones can be recognized at the contact of the anhydrite and the secondary gypsum: (1) massive and/or microporous anhydrite, (2) anhydrite penetrated by tiny gypsum veinlets separating the disturbed crystals and their fragments (commonly along cleavage planes), (3) gypsum with scattered anhydrite relics, and (4) secondary gypsum. The secondary gypsum crystals grow both by replacement and displacement, and also as cement. Displacive growth, evidenced by abundant deformation of the fragmented anhydrite crystals, is the direct cause of the volume increase. Crystallization pressure exerted by gypsum growth is thought to be the main factor generating volume increase and, consequently, also the formation of new fractures allowing water access to “fresh” massive anhydrite and thus accelerating its further hydration. The expansive hydration is taking place within temperature range from 0 to ~30 °C in which the solubility of gypsum is lower than that of anhydrite. In such conditions, dissolving anhydrite yields a solution supersaturated with gypsum and the dissolution of anhydrite is simultaneous with in situ replacive gypsum crystallization. Accompanying displacive growth leads to volume increase in the poorly confined environment of the weathering zone that is susceptible to upward expansion.

scholarly journals Inter-Annual Variability of the Seawater Light Absorption in Surface Layer of the Northeastern Black Sea in Connection with Hydrometeorological Factors

2019 ◽  
Vol 7 (9) ◽  
pp. 326 ◽  
Author(s):  
Anna Yushmanova ◽  
Oleg Kopelevich ◽  
Svetlana Vazyulya ◽  
Inna Sahling
Keyword(s):  
Surface Layer ◽  
Black Sea ◽  
Light Absorption ◽  
Vertical Mixing ◽  
Field Studies ◽  
The Black Sea ◽  
Strong Wind ◽  
Science And Engineering ◽  
Main Factor

Data on the light absorption by seawater and its components are needed in many theoretical and practical aspects of marine science and engineering. However, up to now, there is a lack of such data for the northeastern part of the Black Sea. This article presents the data on light absorption measured by a portable integrated cavity absorption meter (ICAM) spectrophotometer in the Gelendzhik region of the Black Sea during field studies in June 2017 and 2018, together with other bio-optical and oceanographic data from in situ measurements and satellite observations. In 2018, the elevated values of the colored dissolved organic matter (CDOM) absorption in the surface layer were observed concurrently with high values of salinity, contradicting the idea of river runoff being the main CDOM source. The vertical profiles of salinity differed in 2017 and 2018, especially in shallow waters; in the upper layer, the salinity increased from 17.1 psu in 2017 to 17.8 psu in 2018, while the values of CDOM absorption increased from 0.10 to 0.16 m−1. The analysis of available hydrometeorological data pointed to intensive vertical mixing due to the strong wind forcing as a main factor in increasing values of both salinity and the CDOM absorption in the surface layer in 2018.

scholarly journals A85 THE CLINICAL IMPACT OF COVID-19 DELAYS ON PLASTIC BILIARY STENT REMOVAL IN NOVA SCOTIA

2021 ◽  
Vol 4 (Supplement_1) ◽  
pp. 54-56
Author(s):  
D R Lim ◽  
M Tsai ◽  
S E Gruchy ◽  
J Jones ◽  
G Williams ◽  
...  
Keyword(s):  
Survival Analysis ◽  
Nova Scotia ◽  
Stent Placement ◽  
Biliary Stent ◽  
Biliary Stents ◽  
Stent Occlusion ◽  
Stent Removal ◽  
Kaplan Meier ◽  
And Migration

Abstract Background The COVID-2019 pandemic continues to restrict access to endoscopy, resulting in delays or cancellation of non-urgent endoscopic procedures. A delay in the removal or exchange of plastic biliary stents may lead to stent occlusion with consensus recommendation of stent removal or exchange at three-month intervals [1–4]. We postulated that delayed plastic biliary stent removal (DPBSR) would increase complication rates. Aims We aim to report our single-centre experience with complications arising from DPBSR. Methods This was a retrospective, single-center, observational cohort study. All subjects who had ERCP-guided plastic biliary stent placement in Halifax, Nova Scotia between Dec 2019 and June 2020 were included in the study. DPBSR was defined as stent removal >=90 days from insertion. Four endpoints were assigned to patients: 1. Stent removed endoscopically, 2. Died with stent in-situ (measured from stent placement to documented date of death/last clinical encounter before death), 3. Pending removal (subjects clinically well, no liver enzyme elevation, not expired, endpoint 1 Nov 2020), and 4. Complication requiring urgent reintervention. Kaplan-Meier survival analysis was used to represent duration of stent patency (Fig.1). Results 102 (47.2%) had plastic biliary stents placed between 2/12/2019 and 29/6/2020. 49 (48%) were female, and the median age was 68 (R 16–91). Median follow-up was 167.5 days, 60 (58.8%) subjects had stent removal, 12 (11.8%) died before replacement, 21 (20.6%) were awaiting stent removal with no complications (median 230d, R 30–332), 9 (8.8%) had complications requiring urgent ERCP. Based on death reports, no deaths were related to stent-related complications. 72(70.6%) of patients had stents in-situ for >= 90 days. In this population, median time to removal was 211.5d (R 91-441d). 3 (4.2%) subjects had stent-related complications requiring urgent ERCP, mean time to complication was 218.3d (R 94–441). Stent removal >=90 days was not associated with complications such as occlusion, cholangitis, and migration (p=1.0). Days of stent in-situ was not associated with occlusion, cholangitis, and migration (p=0.57). Sex (p=0.275), cholecystectomy (p=1.0), cholangiocarcinoma (p=1.0), cholangitis (p=0.68) or pancreatitis (p=1.0) six weeks prior to ERCP, benign vs. malignant etiology (p=1.0) were not significantly associated with stent-related complications. Conclusions Plastic biliary stent longevity may have been previously underestimated. The findings of this study agree with CAG framework recommendations [5] that stent removal be prioritized as elective (P3). Limitations include small sample size that could affect Kaplan-Meier survival analysis. Despite prolonged indwelling stent time as a result of COVID-19, we did not observe an increased incidence of stent occlusion or other complications. Funding Agencies None

Fabrication of Nanoscale Homogeneous Lead Azide@Carbon Fiber Film with Low Electrostatic Sensitivity by In-situ Synthesis

2021 ◽  
Author(s):  
Zhenzhan Yan ◽  
Li Yang ◽  
Ji-Min Han ◽  
Haojie Li ◽  
Junda Huo
Keyword(s):  
Carbon Fiber ◽  
Lead Acetate ◽  
In Situ Synthesis ◽  
Raw Material ◽  
Lead Azide ◽  
Nano Scale ◽  
Carbon Based

In this work, a nano-scale carbon-based lead azide initiating film was prepared by electrospinning, carbonization, azide, and other steps using cheap and easily available lead acetate as the raw material....

scholarly journals Ag-TON nanospheres coupled with fly ash cenospheres for wastewater treatment under visible light irradiation

2018 ◽  
Vol 78 (11) ◽  
pp. 2321-2327 ◽  
Author(s):  
Yan Ma ◽  
Zhihuan Zhao ◽  
Jimin Fan ◽  
Zhanyong Gu ◽  
Bin Zhang ◽  
...  
Keyword(s):  
Fly Ash ◽  
Visible Light ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Hydrolysis Method ◽  
Composite Photocatalysts ◽  
Recycle And Reuse ◽  
Doping Ratio ◽  
Fly Ash Cenospheres

Abstract Using tetra-n-butyl titanate as raw material and fly ash cenospheres (FAC) as carrier, the photocatalysts of Ag-TON/FAC were successfully prepared by solvothermal and in-situ hydrolysis method. These visible light photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), fluorescence spectroscopy (FL) and UV–vis diffuse reflectance spectra (DRS). In this study, methyl orange and ciprofloxacin were used as wastewater degradation targets to investigate the effect of the amount of titanium dioxide and the amount of Ag doping on the activity of photocatalysts. On the basis of this, the optimal ratio of TiO2 to FAC was 2:1 and the optimum doping ratio of Ag was determined to be 15 wt.%. The composite photocatalysts dispersed uniformly and were easy to recycle and reuse, which were benefits in fully utilizing the solar energy. The degradation efficiency remained at more than 60% after being renewed five times for MO and ciprofloxacin. The photocatalysts of Ag-TON/FAC can reduce the environmental burden caused by FAC also.

scholarly journals Ferum concretions in the soils of the Lviv region

2017 ◽  
pp. 256-266 ◽  
Author(s):  
Zinoviy Pankiv ◽  
Olena Iliasevych ◽  
Stepan Malyk
Keyword(s):  
Unsaturated Soils ◽  
Podzolic Soil ◽  
Soil Material ◽  
Profile Distribution ◽  
High Level ◽  
Soil Forming Processes ◽  
Reducing Potential ◽  
Main Factor ◽  
Brown Color

It is established that ferum concretions can be observed in 60 % area of Lviv’s oblast’s and represented by brown spots, pseudophybras, ortsteins, ortzanders, nodules, layers of marsh ore. In acidic unsaturated soils of Male Polissya, Nadsanya, Precarpathians ferum concretions is the basis for diagnosing soil-forming processes and their genesis. The main factor of ferum concretions formation is the dynamics of oxidation-reducing potential. Fe-Mn pedofetures (ortsteins) dominated in the sodpodzolic gleyed soils of Malogo Pollisya, Nadsanya and in the sod-podzolic pseudogleyed soils of the Precarpathians. Their profile distribution and morphological features. Were established nodules (solid concretions of a dark brown color with a gray tint, irregular shape and with diffuse outlines) were diagnosed within the EI horizon of the brown-podzolic soil of the Precarpathians. Found features of nodules testify about the genesis of in situ. Sod glesish soils of Male Polissya, Precarpathians, valleys Pasmovogo Pobyzzya are characterized by ferum concretions of a dense consistency, a dark brown color with diffuse outlines, which are formed in horizons with long saturation of water due to cementation with soil material of oxides Fe, Al, Mn, Si. Ferum concretions are characterized by maximum accumulation of iron compound (Кх=7,21). Ortzanders and pseudophybras - glandular hydrogenated cemented neoplasms formed are within the profi les of sod pinewood soils of Male Polissya, Nadsanya which were formed on the water-glacial deposits and sod soils in the Davudiv range, formed on Neogene sands on the conditions of high level ironization of ground water and pulsating regime. Little attention is paid to the study of ferum concretions in the soils, which is a significant disadvantage in the study of the genesis of hydromorphic soils. In order to establish the genetic nature, of ferum concretions it is advisable to use modern methods of scanning electronic microscopy, mineralogical and micromorphological studies. Key words: ferum concretions, Fe-Mn pedofetures, ortsteins, nodules, soils.

Assessment of Ferrous Glycinate Liposome Absorption Using in Situ Single-Pass Perfusion Model

2017 ◽  
Vol 13 (9) ◽  
Author(s):  
Baomiao Ding ◽  
Xiangzhou Yi ◽  
Li Li ◽  
Hualin Yang
Keyword(s):  
Particle Size ◽  
Phytic Acid ◽  
Intestinal Permeability ◽  
Iron Absorption ◽  
Inhibitory Effects ◽  
Single Pass ◽  
Pass Perfusion ◽  
Absorption Pathways ◽  
Main Factor

AbstractLiposomes could be employed to improve the absorption of iron. The purpose of this study was to estimate the intestinal permeability of ferrous glycinate liposomes and to assess the effects of phytic acid, zinc and particle size on iron absorption usingin situsingle-pass perfusion in rats. The results showed that the absorption of ferrous glycinate liposomes was obviously higher than that of ferrous glycinate. The inhibitory effects of phytic acid and zinc on iron absorption were reduced by incorporating ferrous glycinate into liposomes. The particle size of ferrous glycinate liposomes was also a main factor for affecting iron absorption, and the intestinal permeability of the liposomes decreased with its particle size increasing. The results suggested that liposomes could be a potent delivery system to decrease the inhibitory effects of phytic acid and zinc and to enhance iron absorption. Furthermore, liposomes could alter the absorption pathways of ferrous glycinate.

scholarly journals Premilinary Results: Heterogeneous Reaction of Epoxidation Palm Kernal Oil

2019 ◽  
Vol 1 (2-2) ◽  
Author(s):  
Mohd Jumain Jalil ◽  
Intan Suhada Azmi ◽  
Arif Aminuddin Ahmad Zulkifli ◽  
Mohamad Helmi Mohd Asbi
Keyword(s):  
Oleic Acid ◽  
Formic Acid ◽  
Analytical Approach ◽  
Heterogeneous Reaction ◽  
Oxygen Carrier ◽  
Raw Material ◽  
Complete Conversion ◽  
In Situ Techniques ◽  
Oxygen Donor

The epoxidized vegetables oils can be used a raw material for a broad range of products, from pharmaceutical and plastics to paint and adhesives. Epoxidation of oleic acid was carried out by using hydrogen peroxide as an oxygen donor and formic acid as an oxygen carrier in the presence of sulphuric acid act as catalyst. The crude oleic acid contained 75% oleic acid, 12.2% linoleic acid, 6.5% palmitic acid and 7.5% stearic acid, and had an iodine value of 98.99 g/100 g. The epoxidation of oleic acid with almost complete conversion of unsaturated carbon and negligible oxirane cleavage can be obtained by the in situ techniques. An analytical approach for the prediction of the partition coefficient for formic acid between oleic acid and water, dependent on temperature and composition, has been proposed.

scholarly journals Quantitative Analysis of Sulpiride and Impurities of 2-Aminomethyl-1-Ethylpyrrolidine and Methyl-5-Sulphamoyl-2-Methoxybenzoate in Pharmaceuticals by High-Performance Thin-Layer Chromatography and Scanning Densitometry

1999 ◽  
Vol 82 (4) ◽  
pp. 825-829 ◽  
Author(s):  
Danica Agbaba ◽  
Tatjana Miljkovic ◽  
Valentina Marinkovic ◽  
Dobrila Zivanov-Stakic ◽  
Sote Vladimirov
Keyword(s):  
Quantitative Analysis ◽  
Thin Layer ◽  
High Performance ◽  
Methylene Chloride ◽  
Solvent System ◽  
Ammonia Solution ◽  
Dosage Forms ◽  
Raw Material ◽  
Layer Chromatography

Abstract A simple and reliable thin-layer chromatographic method for determining sulpiride and impurities of 2-aminomethyl-1-ethylpyrrolidine and methyl-5-sulphamoyl-2-methoxybenzoate was developed and validated. A methylene chloride–methanol–ammonia solution (25%; 18 + 2.8 + 0.4, v/v) solvent system is used for separation and quantitative evaluation of chromatograms. The chromatographic plate is first scanned at 240 nm to locate chromatographic zones corresponding to sulpiride and methyl-5-sulphamoyl-2-methoxybenzoate. Then 2-aminomethyl-1-ethylpyrrolidine is derivatized in situ with ninhydrin, and resulting colored spots are measured at 500 nm. The method is reproducible and convenient for quantitative analysis and purity control of sulpiride in its raw material and in its dosage forms.

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