Temat: dissolution - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Determination of leaching parameters for the recovery of platinum group metals from secondary materials
Autorzy:: Lillkung, K.
Aromaa, J.
Forsen, O.
Tematy:: platinum dissolution
palladium dissolution
rhodium dissolution
chloride concentration; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/109368.pdf Link otwiera się w nowym oknie
Opis:: The leaching parameters for the recovery of platinum group metals were investigated with potentiostatic measurements using wire electrodes. The dissolution rates of Pt, Pd and Rh were measured in concentrated NaCl solution. The parameters inspected were the temperature, redox potential and chloride content. Measurements were done at temperatures 25–94 °C using four different NaCl concentrations, 62.5–250 g/l. Measurements were done at potentials of 950–1250 mV vs. SCE for Pt and Rh and 380–470 mV vs. SCE for Pd. Although higher temperature, potential and chloride content generally increased the dissolution rate, the effect was found to be nonlinear and slightly different for different metals. Based on the results, strongly oxidizing conditions are needed for the leaching process in order to achieve reasonable dissolution rates.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Mercury-free dissolution of aluminum-based nuclear material: from basic science to the plant
Autorzy:: Crooks III, W.
Crown, J.
Dunn, K.
Mickalonis, J.
Murray, A.
Navratil, J.
Tematy:: aluminum dissolution
plutonium oxide dissolution
stainless steel corrosion
mercury-free; Pokaż więcej
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/148380.pdf Link otwiera się w nowym oknie
Opis:: Conditions were optimized for the first plant-scale dissolution of an aluminum-containing nuclear material without using mercury as a catalyst. This nuclear material was a homogeneous mixture of plutonium oxide and aluminum metal that had been compounded for use as the core matrix in Mark 42 nuclear fuel. B ecause this material had later failed plutonium distribution specifications, it was rejected for use in the fabrication of Mark 42 fuel tubes, and was stored at the Savannah River Site (SRS) awaiting disposition. This powder-like material was composed of a mixture of ~80% aluminum and 11% plutonium. Historically, aluminum-clad spent nuclear fuels have been dissolved using a mercuric nitrate catalyst in a nitric acid (HNO3) solution to facilitate the dissolution of the bulk aluminum cladding. Developmental work at SRS indicated that the plutonium oxide/aluminum compounded matrix could be dissolved using boric acid-hydrofluoric acid-nitric acid as a substitute for mercury. Various mercury-free conditions were studied to evaluate the rate of dissolution of the Mark 42 compact material and to assess the corrosion rate to the stainless steel dissolver. The elimination of mercury from the dissolution process fit with waste minimization and industrial hygiene goals to reduce the use of mercury in the United States. The mercury-free dissolution technology was optimized for Mark 42 compact material in laboratory-scale tests, and successfully implemented at the plant.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: The Cistercians in the times of the monasteries dissolution : the case of Jędrzejów and Szczyrzyc : the monastery economy in Szczyrzyc in the first half of the 19th century
Cystersi w dobie kasat : przypadek Jędrzejowa i Szczyrzyca : gospodarka klasztoru w Szczyrzycu w pierwszej połowie XIX wieku
Autorzy:: Kargol, Tomasz
Wydawca:: Towarzystwo Wydawnicze "Historia Iagellonica"
na zlecenie Jędrzejowskiego Towarzystwa Kulturalno-Naukowego
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 4.

Tytuł:: Dissolution kinetics of secondary covellite resulted fromdigenitedissolutionin ferric/acid/chloride media
Autorzy:: Aracena, Alvaro
Espinoza, Camila
Jerez, Oscar
Carvajal, Danilo
Jaques, Aldonza
Tematy:: dissolution kinetics
digenite
covellite
diffusion; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110306.pdf Link otwiera się w nowym oknie
Opis:: Dissolution kinetics of digenite (Cu₉S₅) was studied in Fe³+-H₂SO₄-NaCl media. The temperature range for the study was between 297 and 373 K (24 and 100°C), with a ferric concentration between 0.0100 and 0.0806 mol/dm³, a sulfuric acid concentration of 0.05 to 1.5 mol/dm3 and a NaCl concentration of 1.5 to 5 mol/dm3. Agitation speed and particle size were also studied. Results indicate that the dissolution mechanisms of digenite occurs in two stages: i) generation of covellite (CuS) with the formation of cupric ion (Cu²⁺) and ii) dissolution of covellite (CuS) with copper production in the system, as well as amorphous sulfur (S°). The second stage occurred very slowly compared to the first stage, the above variables studied directly affected the second stage. Temperature, Fe^{3+^{and H₂SO₄ concentration positively affected dissolution of covellite formed (second stage), while the presence of NaCl did not increase dissolution of Cu₉S₅ or CuS. Results showed that stirring speed had an important role in the dissolution rate of CuS. Dissolution kinetics was analyzed using the model of diffusion through the porous layer. Covellite dissolution reaction order was 2.3 and 0.2 with respect to the concentration of ferric and sulfuric acid, respectively, and the rate was inversely proportional to particle size. The calculated activation energy was 36.1 kJ/mol, which is a typical value for a reaction controlled by diffusion in the porous layer at temperature between 297 and 373 K (24 and 100°C).}}
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: The study of physicochemical properties of solid dispersions of ibuprofen in the presence of chitosan
Autorzy:: Grimling, Bożena
Meler, Jan
Szcześniak, Maria
Pluta, Janusz
Górniak, Agata
Tematy:: chitosan
dissolution
ibuprofen
solid dispersion; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Powiązania:: https://bibliotekanauki.pl/articles/1034797.pdf Link otwiera się w nowym oknie
Opis:: The aim of the present study was to increase the solubility of ibuprofen. Among the methods to increase the solubility selected solid dispersions of the drug with the polymer. Chitosan was used as the polymer. Solid dispersion obtained. Ibuprofen was incorporated into the chitosan type 652 with molar masse chitosan Mη = 429 kDa. Solid dispersions were prepared by using different ratios of ibuprofen and chitosan (1:9. 3:7 and 5:5). Formulations were tested dissolution rate of the ibuprofen. The highest dissolution of ibuprofen, amounting to 12.59%, was observed after 60 minutes from solid dispersion prepared by the evaporation method and 12.18% from physical mixtures with drug-polymer weight ratio 1:9 in the presence chitosan. The solubility of the drug improved more than 60-fold. XRPD analysis indicates the presence of the ibuprofen in amorphous form in the solid dispersion obtained by the modified solvent evaporation.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Investigation of fenofibrate solubility in the presence of chitosan
Autorzy:: Grimling, Bożena
Meler, Jan
Pluta, Janusz
Tematy:: chitosan
dissolution
fenofibrate
solid state; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Powiązania:: https://bibliotekanauki.pl/articles/1035391.pdf Link otwiera się w nowym oknie
Opis:: Fenofibrate is an active substance which is well absorbed from the gastrointestinal tract, but it is characterized by limited solubility. Due to a wide spectrum of its pharmacological activity, it would be beneficial to improve its solubility, and thus increase the drug absorption capability. The aim of the study was to investigate the effect of chitosan on the solubility of fenofibrate incorporated into this polymer carrier. The study investigated fenofibrate in solid dispersions at the drug to polymer ratio of 3:7,5:5,7:3. The solubility investigation was performed by means of a dynamic method in a dissolution apparatus; mean amount of dissolved fenofibrate and the drug to polymer quantitative ratio in which the solid dispersion possessed the most beneficial properties improving the drug solubility were calculated. The study revealed a multi-fold increase (from 33 to 50 times) in fenofibrat solubility in the presence of chitosan, which increased with duration of the study and with increasing percentage of the polymer in formulations. The obtained results may help develop new technologies for fenofibrate preparations with chitosan, with better solubility characteristics, and thus increased bioavailability of the drug.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Corrosion of carbonate speleothems by an allogenic river inferred from petrography and a weight loss experiment : a case study from the Demänová Cave System, Slovakia
Autorzy:: Sala, Przemysław
Bella, Paweł
Tematy:: Karst
carbonates
hiatus
dissolution
palaeoenvironment; Pokaż więcej
Wydawca:: Polskie Towarzystwo Geologiczne
Powiązania:: https://bibliotekanauki.pl/articles/27311293.pdf Link otwiera się w nowym oknie
Opis:: The crystallization of speleothems can be interrupted by the invasion of allogenic water into cave passages. These interruptions were studied, both in speleothems currently submerged in an underground river and in speleothem sections, which were found at the lowermost fluvially active passage level of the Demänová Cave System. The interaction between speleothems and allogenic water, undersaturated with respect to calcite, is manifested in the presence of siliciclastic material and the corrosion of calcite crystals. The progressive development of corrosion features depends on the duration of the interaction of calcite crystals with allogenic water. Moreover, the movement of the water and siliciclastic deposition over the speleothems can influence the corrosion process. The estimated rate of corrosion, caused by the underground Demänovka River and measured by the weight loss of experimental tablets, is up to 0.029 mm/y. U-series dating indicated that the interaction of speleothems with allogenic water occurred during the Vistulian (Weichselian). The identification of corrosion episodes, caused by allogenic water, is a step towards understanding the origin of hiatuses and establishing criteria for recognition of them.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: IMPACT OF EXCIPIENTS ON PHARMACEUTICAL AVAILABILITY OF FOLIC ACID FROM TABLETS
Autorzy:: Ostróżka-Cieślik, Aneta
Dolińska, Barbara
Ryszka, Florian
Tematy:: folic acid
dietary supplements
dissolution testing; Pokaż więcej
Wydawca:: Polskie Towarzystwo Farmaceutyczne
Powiązania:: https://bibliotekanauki.pl/articles/895567.pdf Link otwiera się w nowym oknie
Opis:: The impact of excipients contained in individual formulations on the pharmaceutical availability of folic acid was investigated. The release rate of the active substance and the disintegration time of the tablets were analysed. It has been found that in the presence of sorbitol, glucose and starch, 100% of folic acid is released within 60 minutes, and in the presence of lactose and starch - 95%, and the release rates for them are 0.0717 min-1 and 0.0555 min-1 respectively.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Dissolution kinetics of hemimorphite in methane sulfonic acid
Autorzy:: Zhang, Qian
Wen, Shuming
Feng, Qicheng
Nie, Wenlin
Wu, Dandan
Tematy:: hemimorphite
methane sulfonic acid
dissolution
kinetics; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110482.pdf Link otwiera się w nowym oknie
Opis:: Hemimorphite has a large content of zinc, but its recovery using flotation alone is low. Nowadays, hydrometallurgical and pyrometallurgical methods are used to treat zinc ores. In this work, the leaching and dissolution kinetics of hemimorphite by using methane sulfonic acid (MSA) as an alternative leaching reagent was investigated. The effects of several experimental parameters including reaction temperature, MSA concentration, particle size, and stirring speed were also analyzed. Results showed that zinc leaching increased with increased reaction temperature, MSA concentration, and stirring speed, as well as decreased particle size. The mechanism of hemimorphite dissolution in MSA solutions may be a new variant of the shrinking-core model. Based on experimental data and kinetics, the apparent activation energy was determined to be 49.50 kJ/mol. The rate of reaction equation was also obtained to describe the process and found that the MSA concentration largely influenced the leaching of hemimorphite.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Synthesis and solubility of hopeite Zn₃(PO₄)₂·4H₂O
Autorzy:: Bajda, Tomasz
Rogowska, Melania
Pawłowska, Agnieszka
Tematy:: zinc
phosphate
apatite
dissolution
solubility product; Pokaż więcej
Wydawca:: Polskie Towarzystwo Mineralogiczne
Powiązania:: https://bibliotekanauki.pl/articles/46220160.pdf Link otwiera się w nowym oknie
Opis:: Minerals from the phosphate groups are used in environmental engineering as thermodynamically stable vehicles for heavy metals such as zinc. The hopeite Zn₃(PO₄)₂·4H₂O was synthesized and characterized by X-ray diffraction and scanning electron microscopy. The solubility of the hopeite was measured at 25°C. The average solubility product, log K_sp, for the reaction Zn₃(PO₄)₂·4H₂O ⇔ 3Zn²⁺ + 2PO₄ ³⁻ + 4H₂O at 25°C is –35.72 ± 0.03. The free energy of formation, ΔG°f ,298, calculated from this measured solubility product is –3597.4 ± 1.0 kJ mol−1. The immobilization of zinc in the hopeite structure offers the possibility of developing an effective method for removing Zn from wastewater, water and soils.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: Corrosion of carbonate speleothems by bat guano
Autorzy:: Gradziński, Michał
Sala, Przemysław
Postawa, Tomasz
Bella, Pavel
Wróblewski, Wojciech
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 12.

Tytuł:: Dissolution of anisotropic colloidal mineral particles : evidence for basal surface reactivity of nontronite
Autorzy:: Skiba, Michał
Michot, Laurent J.
Grybos, Malgorzata
Billard, Patrick
Mustin, Christian
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 13.

Tytuł:: Optimization of furosemide liquisolid tablets preparation process leading to their mass and size reduction
Autorzy:: Woyna-Orlewicz, Krzysztof
Kurek, Mateusz
Jachowicz, Renata
Khalid, Mohammad Hassan
Opis:: The great number of drug substances currently used in solid oral dosage forms is characterized by poor water solubility. Therefore, various methods of dissolution rate enhancement are an important topic of research interest in modern drug technology. The purpose of this study was to enhance the furosemide dissolution rate from liquisolid tablets while maintaining an acceptable size and mass. Two types of dibasic calcium phosphate (FujicalinÆ/EmcompressÆ) and microcrystalline cellulose (VivapurÆ 102/VivapurÆ 12) were used as carriers and magnesium aluminometasilicate (NeusilinÆ US2) was used as a coating material. The flowable liquid retention potential for those excipients was tested by measuring the angle of slide. To evaluate the impact of used excipients on tablet properties fourteen tablet formulations were prepared. It was found that LS2 tablets containing spherically granulated dibasic calcium phosphate and magnesium aluminometasilicate exhibit the best dissolution profile and mechanical properties while tablets composed only with NeusilinÆ US2 was characterized by the smallest size and mass with preserved good mechanical properties and furosemide dissolution.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 14.

Tytuł:: A multicarotenoid beadlet for human nutrition - proof of concept of in vitro timed release
Autorzy:: Gellenbeck, Kevin
Salter-Venzon, Dawna
Lala, Rajendra
Chavan, Jayanthi
Tematy:: dissolution
carotenoid
bioavailability
controlled release; Pokaż więcej
Wydawca:: Polskie Towarzystwo Biochemiczne
Powiązania:: https://bibliotekanauki.pl/articles/1039766.pdf Link otwiera się w nowym oknie
Opis:: Since the 1980's when the predominate focus of study and use of carotenoids in human nutritional formulations was solely on beta-carotene, there has been a steady increase in research aimed to understand the role of a wide variety of carotenoids in human health. This work has increasingly demonstrated the benefits of a number of carotenoids, and there has been a corresponding increase in the number of carotenoids provided in nutritional supplements (multicarotenoids). Numerous published observations in both human and animal studies suggest significant interaction and competition between various carotenoids during absorption and metabolism, resulting in the inhibition of uptake of one over the other. This competition has the end result of reducing the beneficial effects of the inhibited carotenoid. To limit such competition and maximize carotenoid uptakes, a layered beadlet was designed to release a defined ratio of carotenoids sequentially. Preliminary dissolution testing is presented showing the release profile in simulated digestive conditions of a combination of beta-carotene, alpha carotene, lutein, zeaxanthin, lycopene and astaxanthin derived from natural sources. Comparison is made to an immediate release beadlet formulation using the same combination of carotenoids. These results will be used to guide proof of concept clinical testing for effectiveness in humans.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 15.

Tytuł:: Leaching behaviour of a turkish lateritic ore in the presence of additives
Autorzy:: Basturkcu, H.
Acarkan, N.
Tematy:: laterite
nickel
agitation leaching
dissolution; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110446.pdf Link otwiera się w nowym oknie
Opis:: This paper investigates the dissolution mechanism of a lateritic nickel ore from the Caldag Region of Manisa in Turkey. The ore sample contained 1.2% Ni, 24.8% Fe, and 0.062% Co. The optimum leaching conditions were found to be temperature 80 oC, particle size -74 μm, H2SO4 concentration 200 g/dm3, solids ratio (by weight) 10% and leaching duration 8 h. The extractions of 98.2% Ni, 98.6% Fe and Co 98.9% were obtained under these conditions. Additionally, the effects of additional substances such as NaCl, Na2S2O5, Na2SO4, and KCl were investigated in order to decrease the leaching duration. The results showed that the additives accelerated the leaching kinetics and achieved nearly the same nickel and cobalt extractions at the end of 4 h compared to the results obtained after 8 h without the additives. If the additives containing chlorine were used, it was determined that the iron extraction showed no increase, although both the nickel and cobalt extractions increased.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 16.

Tytuł:: Mixing of endogenous $CO_{2}$ and meteoric $H_{2}O$ causes extremely efficient carbonate dissolution
Autorzy:: Wróblewski, Wojciech
Bella, Pavel
Duliński, Marek
Drewnik, Marek
Nęcki, Jarosław
Gradziński, Michał
Motyka, Jacek
Sala, Przemysław
Opis:: Karst corrosion of carbonate rocks by water with dissolved gases proceeds in most cases along two major scenarios: (i) meteoric water absorbs $CO_{2}$ from soil and atmosphere, or (ii) ascending water of deep circulation carries with it dissolved endogenous gases, mainly $CO_{2}$ and $H_{2}O$. We have observed a peculiar variant where meteoric water absorbs ascending endogenous gases at a natural gas vent on a travertine mound in Slovakia. Carbonate dissolution's extreme effectiveness is demonstrated by mineralization of rainwater ponded at a gas vent, rising to 3.2 g/L of dissolved solids shortly after the rainfall. One liter of water ponded at the vent and mixing with the venting gas, dissolved up to 800 mg of calcium at a rate exceeding 5.8 mg/L·min. Limestone tablets placed at the vent show signs of significant corrosion, at rates up to 126 mm/ka. The rate is comparable to those in coastal karst, where freshwater is mixing with seawater and to those in sulfuric acid speleogenesis (SAS), both the highest hitherto known rates of karst corrosion in carbonates. The geomorphic effects of the process described are depressions on the surface of travertine near the vents of endogenous $CO_{2}$. This type of corrosion seems to be universal and probably occurs everywhere where endogenous $CO_{2}$ is exhaled to the surface from carbonate rocks.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 17.

Tytuł:: Corrosion of carbonate speleothems by an allogenic river inferred from petrography and a weight loss experiment : a case study from the Demänová Cave System, Slovakia
Autorzy:: Bella, Pavel
Sala, Przemysław
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 18.

Tytuł:: Surface-charging and particles aggregation behavior of ascharite
Autorzy:: Li, Zhihang
Han, Yuexin
Zuo, Kesheng
Tematy:: ascharite
surface charge
incongruent dissolution
particles aggregation; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/109441.pdf Link otwiera się w nowym oknie
Opis:: Surface charging and particles aggregation ascharite are investigated through Zeta potential measurement, XPS analysis, SEM analysis and dissolution experiments. The results show that more Mg²⁺ are removed from ascharite surface after dissolution, which confirms that incongruent dissolution of ions in the case of certain ionic substances like rmagnesium ions, hydroxyl groups and borate ions can lead to a net charge on surface. Isomorphous substitution of Fe³⁺ for Mg²⁺ is also regarded as one factor that causes surface charging behavior, which is in consistent with the experimental data. The dissolution process is analyzed to show more details about the dissolution reactions. The disparity in the bonding energy of B–O and Mg–OH surface groups and the difference in free energy of hydration of surface groups are considered to be the basic reason that lead to incongruent dissolution. Eventually, the effect of surface potential on particles aggregation is analyzed by DLVO theory, indicating that dissolution of ascharite has a detrimental effect on particles dispersion.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 19.

Tytuł:: Synthesis and solubility of brompyromorphite Pb5(PO4)3Br
Autorzy:: Janicka, Urszula
Bajda, Tomasz
Manecki, Maciej
Tematy:: lead
phosphate
apatite
dissolution
brompyromorphite
solubility product; Pokaż więcej
Wydawca:: Polskie Towarzystwo Mineralogiczne
Powiązania:: https://bibliotekanauki.pl/articles/127627.pdf Link otwiera się w nowym oknie
Opis:: The bromide analogue of pyromorphite Pb5(PO4)3Br was synthesized and characterized by X-ray diffraction, infrared spectroscopy and scanning electron microscopy. The solubility of the brompyromorphite was measured at 25°C and pH values of 2.0, 2.6 and 3.2. For the 3 pH measurements, the average solubility product, log KSP, for the reaction Pb5(PO4)3Br 5Pb2+ + 3PO4 3– + Br– at 25ºC is –77.38 ± 0.70. The free energy of formation, Gf,298, calculated from this measured solubility product is –3724.7 ± 4.3 kJ mol−1. These results confirm that brompyromorphite is more soluble than pyromorphite.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 20.

Tytuł:: A Rational approach to predicting immediate release formulation behavior in multiple gastric motility patterns : a combination of a biorelevant apparatus, design of experiments, and machine learning
Autorzy:: Garbacz, Grzegorz
Myslitska, Daria
Danielak, Dorota
Romanova, Svitlana
Paszkowska, Jadwiga
Staniszewska, Marcela
Dobosz, Justyna
Polak, Sebastian
Romański, Michał
Opis:: Gastric mechanical stress often impacts drug dissolution from solid oral dosage forms, but in vitro experiments cannot recreate the substantial variability of gastric motility in a reasonable time. This study, for the first time, combines a novel dissolution apparatus with the design of experiments (DoE) and machine learning (ML) to overcome this obstacle. The workflow involves the testing of soft gelatin capsules in a set of fasted-state biorelevant dissolution experiments created with DoE. The dissolution results are used by an ML algorithm to build the classification model of the capsule’s opening in response to intragastric stress (IS) within the physiological space of timing and magnitude. Next, a random forest algorithm is used to model the further drug dissolution. The predictive power of the two ML models is verified with independent dissolution tests, and they outperform a polynomial-based DoE model. Moreover, the developed tool reasonably simulates over 50 dissolution profiles under varying IS conditions. Hence, we prove that our method can be utilized for the simulation of dissolution profiles related to the multiplicity of individual gastric motility patterns. In perspective, the developed workflow can improve virtual bioequivalence trials and the patient-centric development of immediate-release oral dosage forms.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 21.

Tytuł:: The impact of fossils on diagenetically controlled reservoir quality : the Zechstein Brońsko Reef
Autorzy:: Fheed, Adam
Tematy:: carbonates
dissolution channels
diagenesis
fossils
porosity; Pokaż więcej
Wydawca:: Polskie Towarzystwo Geologiczne
Powiązania:: https://bibliotekanauki.pl/articles/191256.pdf Link otwiera się w nowym oknie
Opis:: Although the sedimentation and diagenesis of the Polish Zechstein Limestone strata (Ca1, Permian) already have been investigated, relatively little has been done to resolve their petrophysical potential. Therefore, the gap between sedimentological and petrophysical studies was bridged through an integrated analysis of geological and geophysical data. The results of core description, polarized-light microscopy, well log interpretations and laboratory measurements on core samples were combined with previously published nuclear magnetic resonance (NMR) and X-ray microtomography (μCT) data, especially helpful in the recognition of pore geometry. The Ca1 strata of the Brońsko-1 and Brońsko-2 wells, located on the Zechstein Brońsko Reef (West Poland), were studied to determine the influence of fossils on porosity and permeability. It was concluded that greater diversification of the original biota led to an increase in porosity and variation in pore geometry. While encrusting organisms such as foraminifers promoted the development of channel and fracture porosity, the dissolution of the primarily aragonitic bivalve and gastropod shells and the shells of terebratulid brachiopods often gave rise to the formation of cavernous and mouldic porosity. The channels appear to be most common in the bryozoan-foraminifer biofacies, representing a shallowing of the depositional environment. Caverns, in turn, corresponded to the organisms of the brachiopod-bryozoan and the lightly karstified bivalve-gastropod biofacies, both of which probably experienced the influence of sabkha conditions, leading to a general decrease in porosity. The bryozoan zoecia tended to enhance both primary intraparticle voids, and after their dissolution, secondary intraparticle pores, which showed limited connectivity in the high-energy Acanthocladia biofacies, where considerable fragmentation of fossils took place, hence decreasing the permeability. Anhydrite cementation was found to be the most pronounced factor controlling porosity destruction, while dolomitization enhanced it significantly, especially for the stromatolitic biofacies, where small, unconnected vugs were formed owing to this process. The permeability is typically below 100 mD, and this is caused by the rich diagenetic history of the reef, that recorded marine, sabkha-related and burial cementation, now represented by the different fabrics of anhydrite, calcite, and dolomite.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 22.

Tytuł:: Aqueous cadmium removal by hydroxylapatite and fluoroapatite
Autorzy:: Matusik, J.
Bajda, T.
Manecki, M.
Tematy:: Ca-Cd phosphate
mineral dissolution
immobilization; Pokaż więcej
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:: https://bibliotekanauki.pl/articles/184550.pdf Link otwiera się w nowym oknie
Opis:: Reducing the bioavailability of toxic heavy metals in groundwaters and urban soils by phosphate addition is an effective technique described in the literature. It is based on the reaction between metal ions and phosphates and results in the precipitation of metal substituted phosphate phases. The formed phosphates are highly insoluble and thermodynamically stable over almost entire pH and Eh range. In the presented study the efficiency and mechanism of cadmium uptake by synthetic hydroxylapatite and natural fluoroapatite was examined within the pH range of 3-7 for different reaction times (2—1440 hours). The solids after reactions were characterized by XRD and SEM-EDS. Percentage reduction of cadmium concentration in the experiments with fluoroapatite and hydroxylapatite, regardless of pH, did not exceed 17% and 25%, respectively. Cadmium uptake from the solution mainly resulted from the formation of cadmium phosphates and/or Ca-Cd phosphate solid solutions on the apatites surface. The release rate of phosphate ions by hydroxylapatite was relatively high. This promoted crystallization of a large number of small crystals. In turn dissolution of fluoroapatite was slower and thus the formation of large crystals was observed. There was no clear evidence for cadmium-calcium ion-exchange mechanism.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 23.

Tytuł:: Leaching of chalcopyrite concentrate in hydrogen peroxide solution
Autorzy:: Agacayak, T.
Aras, A.
Aydogan, S.
Erdemoglu, M.
Tematy:: chalcopyrite
dissolution
hydrogen peroxide
leaching
extraction; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110645.pdf Link otwiera się w nowym oknie
Opis:: The leaching conditions of chalcopyrite (CuFeS2) concentrate in a hydrogen peroxide medium were investigated by studying the effects of its leaching parameters, such as stirring speed, temperature, hydrogen peroxide concentration and the particle size of the concentrate on Cu extraction. It was found that stirring speed has no effect on the leaching. Copper extraction from chalcopyrite is directly proportional to hydrogen peroxide concentration, but the extraction decreases at temperatures above 60°C. The maximum copper extraction was obtained with the following conditions without stirring: 240 min of leaching time, 3.0 M hydrogen peroxide concentration, 40°C leaching temperature and 53-75 m particle size fraction.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 24.

Tytuł:: Optimization of pure borax pentahydrate extraction from calcined tincal
Autorzy:: Abali, Y.
Bayca, S. U.
Edgunlu, G.
Tematy:: optimization
calcined tincal
borax
dissolution
leaching
Taguchi method; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/109778.pdf Link otwiera się w nowym oknie
Opis:: In this study, conditions for the calcination process of tincal were investigated and the optimum calcination conditions for boron extraction from tincal were determined. The experimental parameters were dissolution temperature, solid-to-liquid ratio, dissolution time and stirring speed. The optimum dissolution parameter levels were determined to be temperature 80 °C, solid-to-liquid ratio 10 g/dm3, stirring speed 250 rpm and dissolution time 5 min.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 25.

Tytuł:: Dissolution kinetics of malachite in ethylene diamine phosphate solutions
Autorzy:: Shen, Peilun
Liu, Ruizeng
Liu, Dianwen
Zhan, Xiaolin
Jia, Xiaodong
Song, Kaiwei
Tematy:: malachite
organic amine
ethylene diamine phosphate
dissolution
kinetic; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110214.pdf Link otwiera się w nowym oknie
Opis:: Ethylene diamine phosphate (EDP), as a synthetic organic reagent, was used for the first time to leach malachite, and a new method of using organic amine to leach copper oxide ore was developed. The effects of stirring speed, particle size, reagent concentration, and reaction temperature on EDP-dissolution malachite were investigated. Results showed that malachite rapidly dissolved in EDP solution. The malachite-dissolving rate also increased with increased reagent concentration, increased reaction temperature, and decreased particle size. Stirring speed exhibited nearly no effect on EDP-induced malachite dissolution. The leaching kinetics was found to follow the shrinking-core model, and dissolution was controlled by surface chemical reaction with an activation energy of 52.63kJ×mol⁻¹. A semiempirical rate equation was obtained to describe the dissolution process expressed as 1-(1-X_Cu)^1/3=0.0149(C_EDP)^0.7814 × (P_malachite)^−0.7982×exp(−6.3308/T) ×t.
Dostawca treści:: Biblioteka Nauki

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