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1
Cretu, Carmen, Roxana Nicola, Sorin-Alin Marinescu, Elena-Mirela Picioruș, Mariana Suba, Corina Duda-Seiman, Adel Len, Levente Illés, Zsolt Endre Horváth, and Ana-Maria Putz. "Performance of Zr-Based Metal–Organic Framework Materials as In Vitro Systems for the Oral Delivery of Captopril and Ibuprofen." International Journal of Molecular Sciences 24, no. 18 (September 9, 2023): 13887. http://dx.doi.org/10.3390/ijms241813887.
Abstract:
Zr-based metal–organic framework materials (Zr-MOFs) with increased specific surface area and pore volume were obtained using chemical (two materials, Zr-MOF1 and Zr-MOF3) and solvothermal (Zr-MOF2) synthesis methods and investigated via FT-IR spectroscopy, TGA, SANS, PXRD, and SEM methods. The difference between Zr-MOF1 and Zr-MOF3 lies in the addition of reactants during synthesis. Nitrogen porosimetry data indicated the presence of pores with average dimensions of ~4 nm; using SANS, the average size of the Zr-MOF nanocrystals was suggested to be approximately 30 nm. The patterns obtained through PXRD were characterized by similar features that point to well-crystallized phases specific for the UIO-66 type materials; SEM also revealed that the materials were composed of small and agglomerate crystals. Thermogravimetric analysis revealed that both materials had approximately two linker deficiencies per Zr6 formula unit. Captopril and ibuprofen loading and release experiments in different buffered solutions were performed using the obtained Zr-based metal–organic frameworks as drug carriers envisaged for controlled drug release. The carriers demonstrated enhanced drug-loading capacity and showed relatively good results in drug delivery. The cumulative percentage of drug release in phosphate-buffered solution at pH 7.4 was higher than that in buffered solution at pH 1.2. The release rate could be controlled by changing the pH of the releasing solution. Different captopril release behaviors were observed when the experiments were performed using a permeable dialysis membrane.
2
Borzacchiello, Assunta, Luisa Russo, Birgitte M. Malle, Khadija Schwach-Abdellaoui, and Luigi Ambrosio. "Hyaluronic Acid Based Hydrogels for Regenerative Medicine Applications." BioMed Research International 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/871218.
Abstract:
Hyaluronic acid (HA) hydrogels, obtained by cross-linking HA molecules with divinyl sulfone (DVS) based on a simple, reproducible, and safe process that does not employ any organic solvents, were developed. Owing to an innovative preparation method the resulting homogeneous hydrogels do not contain any detectable residual cross-linking agent and are easier to inject through a fine needle. HA hydrogels were characterized in terms of degradation and biological properties, viscoelasticity, injectability, and network structural parameters. They exhibit a rheological behaviour typical of strong gels and show improved viscoelastic properties by increasing HA concentration and decreasing HA/DVS weight ratio. Furthermore, it was demonstrated that processes such as sterilization and extrusion through clinical needles do not imply significant alteration of viscoelastic properties. Both SANS and rheological tests indicated that the cross-links appear to compact the network, resulting in a reduction of the mesh size by increasing the cross-linker amount. In vitro degradation tests of the HA hydrogels demonstrated that these new hydrogels show a good stability against enzymatic degradation, which increases by increasing HA concentration and decreasing HA/DVS weight ratio. Finally, the hydrogels show a good biocompatibility confirmed by in vitro tests.
3
Macošek, Jakub, Bernd Simon, Johanna-Barbara Linse, Pravin Kumar Ankush Jagtap, Sophie L. Winter, Jaelle Foot, Karine Lapouge, et al. "Structure and dynamics of the quaternary hunchback mRNA translation repression complex." Nucleic Acids Research 49, no. 15 (July 30, 2021): 8866–85. http://dx.doi.org/10.1093/nar/gkab635.
Abstract:
Abstract A key regulatory process during Drosophila development is the localized suppression of the hunchback mRNA translation at the posterior, which gives rise to a hunchback gradient governing the formation of the anterior-posterior body axis. This suppression is achieved by a concerted action of Brain Tumour (Brat), Pumilio (Pum) and Nanos. Each protein is necessary for proper Drosophila development. The RNA contacts have been elucidated for the proteins individually in several atomic-resolution structures. However, the interplay of all three proteins during RNA suppression remains a long-standing open question. Here, we characterize the quaternary complex of the RNA-binding domains of Brat, Pum and Nanos with hunchback mRNA by combining NMR spectroscopy, SANS/SAXS, XL/MS with MD simulations and ITC assays. The quaternary hunchback mRNA suppression complex comprising the RNA binding domains is flexible with unoccupied nucleotides functioning as a flexible linker between the Brat and Pum-Nanos moieties of the complex. Moreover, the presence of the Pum-HD/Nanos-ZnF complex has no effect on the equilibrium RNA binding affinity of the Brat RNA binding domain. This is in accordance with previous studies, which showed that Brat can suppress mRNA independently and is distributed uniformly throughout the embryo.
4
Krishnan, Mohan Raj, and Edreese Housni Alsharaeh. "Polymer gel amended sandy soil with enhanced water storage and extended release capabilities for sustainable desert agriculture." Journal of Polymer Science and Engineering 6, no. 1 (November 7, 2023): 2892. http://dx.doi.org/10.24294/jpse.v6i1.2892.
Abstract:
Herein, we report a facile preparation of super-hydrophilic sand by coating the sand particles with cross-linked polyacrylamide (PAM) hydrogels for enhanced water absorption and controlled water release aimed at desert agriculture. To prepare the sample, 4wt% of aqueous PAM solution is mixed with organic cross-linkers of hydroquinone (HQ) and hexamethylenetetramine (HMT) in 1:1 weight ratio and aqueous potassium chloride (KCl) solution. A specific amount of the above solution is added to the sand well mixed and subsequently cured at 150 °C for 8 h. The prepared super-hydrophilic sands were characterized by Fourier-transform infrared spectroscopy (FT-IR) for chemical composition and X-ray diffraction (XRD) for successful polymer coating onto the sand. The water storage for the samples was studied by absorption kinetics at various temperature conditions and extended water release was studied by the water desorption kinetics. The water swelling ratio for the super-hydrophilic sand has reached a maximum of 900% (9 times its weight) at 80 °C within 1 h. The desorption kinetics of the samples showed that the water can be stored for up to a maximum of 3 days. Therefore, super-hydrophilic sand particles were successfully prepared by coating with PAM hydrogels with a great potential to be used in sustainable desert agriculture.
5
Maccarrone, S., H. Frielinghaus, J. Allgaier, D. Richter, and P. Lindner. "SANS Study of Polymer-Linked Droplets." Langmuir 23, no. 19 (September 2007): 9559–62. http://dx.doi.org/10.1021/la7020353.
6
Wolfe, Stephen A., Olav B. Lian, Christopher H. Hugenholtz, and Justine R. Riches. "Holocene eolian sand deposition linked to climatic variability, Northern Great Plains, Canada." Holocene 27, no. 4 (October 7, 2016): 579–93. http://dx.doi.org/10.1177/0959683616670223.
Abstract:
The Bigstick and Seward Sand Hills are possibly two of the oldest dune fields within the late Wisconsin glaciated regions of the Northern Great Plains. As with most Northern Great Plains dune fields, source sediments are former proglacial outwash sands. Thus, Holocene dune construction is primarily related to spatial–temporal variations in surface cover and transport capacity, rather than renewed sediment input. However, eolian landscape reconstructions on the Northern Great Plains have been temporally constrained to recent periods of activity, as older episodes of deposition are typically reworked by younger events. In this study, sediment cores from shallow lacustrine basins and interdune areas provide an improved record of Holocene eolian sand deposition. Eolian sand accumulation in the interdunes and basins occurred between 150 and 270 years ago, 1.9 and 3.0 ka, 5.4 and 8.6 ka, and prior to ca. 10.8 ka. These episodes of sand accumulation were bracketed by lacustrine deposition and soil formation, which represented wetter conditions. Other than mid-Holocene dune activity, which may be related to peak warmth and aridity, most periods of eolian sand accumulation coincided with cooler but drier climatic events such as the Younger Dryas, late-Holocene cooling prior to the Medieval Climatic Anomaly, and the ‘Little Ice Age’. These depositional episodes are also spatially represented by other dune fields in the region, providing a broad-scale view of the connections between past climatic events and eolian landscape evolution on the Northern Great Plains.
7
PRINZ, LINDA, TOM McCANN, ANDREAS SCHÄFER, SVEN ASMUS, and PETER LOKAY. "The geometry, distribution and development of sand bodies in the Miocene-age Frimmersdorf Seam (Garzweiler open-cast mine), Lower Rhine Basin, Germany: implications for seam exploitation." Geological Magazine 155, no. 3 (November 23, 2016): 685–706. http://dx.doi.org/10.1017/s0016756816000960.
Abstract:
AbstractThe Cenozoic-age Lower Rhine Basin is located in the NW part of the European Cenozoic Rift System. In Miocene times, a combination of warm climatic conditions and basin subsidence resulted in the deposition of up to 100m of lignite (i.e. Main Seam of the Ville Formation). The Main Seam can be subdivided into the Morken, Frimmersdorf and Garzweiler seams, separated by two intercalated transgressive sand units, namely the Frimmersdorf and Neurath sands, deposited in a shallow-marine, tide-dominated environment. The lignite seams of the Ville Formation are currently worked by RWE Power AG, in the Garzweiler II open-cast mine. In the Frimmersdorf Seam (between the Frimmersdorf Sand and the Neurath Sand), the presence of small-scale sand bodies, together with their variable dimensions, affects the industrial exploitation of the seam. Moreover, their irregular distribution complicates their precise and early recognition. Indeed, so-called barren lignite (≥ 17% of sand) and completely clean units can occur within a few metres of each other. Initial classification of these highly variable sand bodies suggests a variety of both pre- and post-depositional causal mechanisms, providing evidence of an extremely complex depositional and post-depositional system. Syn-depositional sand bodies were deposited in a swamp area that was located in the fluvial-dominated sub-environment of an extended tidal estuary. The post-depositional formation of sand bodies is related to the intrusion of fluidized sands from the underlying Frimmersdorf Sand. These sand injectites within the Frimmersdorf Seam are considered to be linked to seismic activity within the Lower Rhine Basin.
8
Colijn, Caroline, David JD Earn, Jonathan Dushoff, Nicholas H. Ogden, Michael Li, Natalie Knox, Gary Van Domselaar, Kristyn Franklin, Gordon Jolly, and Sarah P. Otto. "La nécessité d’une surveillance génomique liée du SRAS-CoV-2." Relevé des maladies transmissibles au Canada 48, no. 4 (April 6, 2022): 147–55. http://dx.doi.org/10.14745/ccdr.v48i04a03f.
Abstract:
La surveillance génomique au cours de la pandémie de maladie à coronavirus 2019 (COVID-19) a été essentielle pour repérer en temps utile les variants du virus ayant des conséquences importantes pour la santé publique, telles que les variants qui peuvent se transmettre et provoquer une maladie grave chez les personnes vaccinées ou guéries. L’émergence rapide du variant Omicron a mis en évidence la rapidité avec laquelle l’étendue d’une menace doit être évaluée. Le séquençage rapide et l’ouverture des institutions de santé publique au partage international des données de séquençage offrent une occasion sans précédent de le faire. Toutefois, l’évaluation des propriétés épidémiologiques et cliniques de tout nouveau variant reste un défi. Nous mettons ici en évidence un « groupe de quatre » sources de données clés qui peuvent aider à détecter les variants viraux qui menacent la gestion de la COVID-19 : 1) des données génétiques (séquence du virus), 2) des données épidémiologiques et géographiques, 3) des données cliniques et démographiques, et 4) des données sur la vaccination. Nous soulignons les avantages qui peuvent être obtenus en reliant les données de ces sources et en combinant les données de ces sources avec les données de séquences virales. Les défis considérables que représente la mise à disposition des données génomiques et les coupler avec les caractéristiques des virus et des patients doivent être comparés aux conséquences majeures de ne pas le faire, notamment si de nouveaux variants préoccupants apparaissent et se propagent sans être détectés et traités à temps.
9
Bobrowski, A., S. Żymankowska-Kumon, D. Drożyński, B. Grabowska, and K. Kaczmarska. "TG/DTG/DTA, FTIR and GC/MS Studies of Oil Sand for Artistic and Precision Foundry with the Emission of Gases Assessment." Archives of Foundry Engineering 17, no. 4 (December 20, 2017): 25–30. http://dx.doi.org/10.1515/afe-2017-0125.
Abstract:
AbstractThe paper presents the results of thermoanalytical studies by TG/DTG/DTA, FTIR and GC/MS for the oil sand used in art and precision foundry. On the basis of course of DTG and DTA curves the characteristic temperature points for thermal effects accompanying the thermal decomposition reactions were determined. This results were linked with structural changes occurred in sample. It has been shown that the highest weight loss of the sample at temperatures of about 320°C is associated with destruction of C-H bonds (FTIR). In addition, a large volume of gases and high amounts of compounds from the BTEX group are generated when liquid metal interacts with oil sand. The results show, that compared to other molding sands used in foundry, this material is characterized by the highest gaseous emissions and the highest harmfulness, because benzene emissions per kilogram of oil sand are more than 7 times higher than molding sand with furan and phenolic binders and green sand with bentonite and lustrous carbon carrier.
10
Zeybek, Abdülhakim. "Experimental and Empirical Studies to Evaluate Liquefaction Resistance of Partially Saturated Sands." Applied Sciences 13, no. 1 (December 21, 2022): 81. http://dx.doi.org/10.3390/app13010081.
Abstract:
Partially saturated sands with occluded gas bubbles may occur naturally in the field or can be created artificially as a way of mitigating liquefaction effects. This study aimed to investigate the main parameters that influence the liquefaction resistance of partially saturated sands containing occluded gas bubbles. It also adopted a simplified approach and proposed empirical relationships that linked the liquefaction-resistance ratio to the bulk modulus, maximum volumetric strain, and excess pore-pressure ratio. Considering these objectives, a total of 60 stress-controlled dynamic triaxial tests were conducted. Nearly/fully saturated and partially saturated sand specimens prepared using sodium percarbonate were subjected to undrained cyclic loading with a loading frequency of 0.1 Hz. The loosely or densely packed sand specimens at different degrees of saturation (79–100%) were examined under different initial effective confining stresses (25–100 kPa) and back pressures (100–400 kPa). The analysis of the test results indicated that the liquefaction resistance of the partially saturated sands constantly increased as the degree of saturation decreased, and this effect was more prominent under higher initial effective confining stresses and lower back pressures. The adopted method satisfactorily captured this trend and showed reasonable matches between the empirical predictions and experimentally observed results from this study and previous research.
11
Akacem, Mustapha, Moulay Omar Hassan, Driss Djafari, and Mohammed Abbou. "Valuation of Local Materials in Road Construction in Arid Zones." Algerian Journal of Renewable Energy and Sustainable Development 3, no. 2 (December 15, 2021): 115–31. http://dx.doi.org/10.46657/ajresd.2021.3.2.1.
Abstract:
The materials constituting the pavement bodies, until today, have been limited to certain so-called noble materials (rolled sands, aggregates, etc.), but these are in the process of being exhausted under the effect of intensive exploitation and the scarcity of quality quarries. With the objective of preserving the deposits of aggregates in the process of exhaustion for future generations and of exploiting the aeolian sands in abundance in the regions of southern Algeria, we aim to enhance the latter in the body of the roadway mixed with the tuffs, this would imply a reduction in construction costs (use of local aggregates of lower quality available in large quantities, reduction in transport costs). From an environmental point of view, this would limit the impacts with a reduction in CO2 emissions linked to transport. In this work, we applied a new approach based on the technique of mixtures to valorize and exploit the sand of dunes existing in abundance, with the treatment in hydraulic binders, which allowed us to go up to 20% of sand dunes
12
Grabowska, B., A. Bobrowski, E. Olejnik, and K. Kaczmarska. "Using Selected Chemical and Physical Factors to Cross-link a BioCo Polymer Binder - Mineral Matrix System / Zastosowanie wybranych czynników chemicznych i fizycznych w procesie sieciowania układu spoiwo polimerowe BioCo – osnowa mineralna." Archives of Foundry Engineering 13, no. 2 (June 1, 2013): 29–34. http://dx.doi.org/10.2478/afe-2013-0031.
Abstract:
Abstract This publication describes research on the course of the process of cross-linking new BioCo polymer binders - in the form of water-based polymer compositions of poly(acrylic acid) or poly(sodium acrylate)/modified polysaccharide - using selected physical and chemical factors. It has been shown that the type of cross-linking factor used influences the strength parameters of the moulding sand. The crosslinking factors selected during basic research make it possible to obtain sand strengths similar to those of samples of sands bonded with commercial binders. Microwave radiation turned out to be the most effective cross-linking factor in a binder-matrix system. It was proven that adsorption in the microwave radiation field leads to the formation of polymer lattices with hydrogen bonds which play a major role in maintaining the formed cross-linked structures in the binder-matrix system. As a result, the process improves the strength parameters of the sand, whereas the hardening process in a microwave field significantly shortens the setting time.
13
Stachowicz, M., M. Kamiński, K. Granat, and Ł. Pałyga. "Effect of Temperature on Chromite-Based Moulding Sands Bonded with Sodium Silicate." Archives of Foundry Engineering 16, no. 4 (December 1, 2016): 147–52. http://dx.doi.org/10.1515/afe-2016-0100.
Abstract:
Abstract In the paper, a research on effects of baking temperature on chromite sand base of moulding sands bonded with sodium silicate is presented. Pure chromite sand and its chromite-based moulding sand prepared with use of sodium silicate were subjected to heating within 100 to 1200 °C. After cooling-down, changes of base grains under thermal action were determined. Chromite moulding sand was prepared with use of 0.5 wt% of domestic made, unmodified sodium silicate (water-glass) grade 145. After baking at elevated temperatures, creation of rough layer was observed on grain surfaces, of both pure chromite sand and that used as base of a moulding sand. Changes of sand grains were evaluated by scanning microscopy and EDS analyses. It was found that changes on grain surfaces are of laminar nature. The observed layer is composed of iron oxide (II) that is one of main structural components of chromite sand. In order to identify changes in internal structure of chromite sand grains, polished sections were prepared of moulding sand hardened with microwaves and baked at elevated temperatures. Microscopic observations revealed changes in grains structure in form of characteristically crystallised acicular particles with limited magnesium content, intersecting at various angles. EDS analysis showed that these particles are composed mostly of chromium oxide (III) and iron oxide (II). The temperature above that the a.m. changes are observed in both chromite-based moulding sand and in pure chromite sand. The observed phenomena were linked with hardness values and mass of this sand.
14
Stachowicz, M., M. Kamiński, K. Granat, and Ł. Pałyga. "Effect of Temperature on Chromite-Based Moulding Sands Bonded with Sodium Silicate." Archives of Foundry Engineering 17, no. 2 (June 27, 2017): 95–100. http://dx.doi.org/10.1515/afe-2017-0058.
Abstract:
Abstract In the paper, a research on effects of baking temperature on chromite sand base of moulding sands bonded with sodium silicate is presented. Pure chromite sand and its chromite-based moulding sand prepared with use of sodium silicate were subjected to heating within 100 to 1200 °C. After cooling-down, changes of base grains under thermal action were determined. Chromite moulding sand was prepared with use of 0.5 wt% of domestic made, unmodified sodium silicate (water-glass) grade 145. After baking at elevated temperatures, creation of rough layer was observed on grain surfaces, of both pure chromite sand and that used as base of a moulding sand. Changes of sand grains were evaluated by scanning microscopy and EDS analyses. It was found that changes on grain surfaces are of laminar nature. The observed layer is composed of iron oxide (II) that is one of main structural components of chromite sand. In order to identify changes in internal structure of chromite sand grains, polished sections were prepared of moulding sand hardened with microwaves and baked at elevated temperatures. Microscopic observations revealed changes in grains structure in form of characteristically crystallised acicular particles with limited magnesium content, intersecting at various angles. EDS analysis showed that these particles are composed mostly of chromium oxide (III) and iron oxide (II). The temperature above that the a.m. changes are observed in both chromite-based moulding sand and in pure chromite sand. The observed phenomena were linked with hardness values and mass of this sand.
15
Lyu, Zhaoyuan, Shichao Ding, Nan Zhang, Yang Zhou, Nan Cheng, Maoyu Wang, Mingjie Xu, et al. "Single-Atom Nanozymes Linked Immunosorbent Assay for Sensitive Detection of Aβ 1-40: A Biomarker of Alzheimer’s Disease." Research 2020 (October 19, 2020): 1–11. http://dx.doi.org/10.34133/2020/4724505.
Abstract:
Single-atom nanozymes (SANs) possess unique features of maximum atomic utilization and present highly assembled enzyme-like structure and remarkable enzyme-like activity. By introducing SANs into immunoassay, limitations of ELISA such as low stability of horseradish peroxidase (HRP) can be well addressed, thereby improving the performance of the immunoassays. In this work, we have developed novel Fe-N-C single-atom nanozymes (Fe-Nx SANs) derived from Fe-doped polypyrrole (PPy) nanotube and substituted the enzymes in ELISA kit for enhancing the detection sensitivity of amyloid beta 1-40. Results indicate that the Fe-Nx SANs contain high density of single-atom active sites and comparable enzyme-like properties as HRP, owing to the maximized utilization of Fe atoms and their abundant active sites, which could mimic natural metalloproteases structures. Further designed SAN-linked immunosorbent assay (SAN-LISA) demonstrates the ultralow limit of detection (LOD) of 0.88 pg/mL, much more sensitive than that of commercial ELISA (9.98 pg/mL). The results confirm that the Fe-Nx SANs can serve as a satisfactory replacement of enzyme labels, which show great potential as an ultrasensitive colorimetric immunoassay.
16
Kitagawa, Toshikazu, Takashi Kawano, Takahiro Hase, Ikuma Hayakawa, Katsuyuki Hirai, and Takao Okazaki. "Electron-Transfer Properties of Phenyleneethynylene Linkers Bound to Gold via a Self-Assembled Monolayer of Molecular Tripod." Molecules 23, no. 11 (November 6, 2018): 2893. http://dx.doi.org/10.3390/molecules23112893.
Abstract:
The three-point adsorption of tripod-shaped molecules enables the formation of robust self-assembled monolayers (SAMs) on solid surfaces, where the component molecules are fixed in a strictly upright orientation. In the present study, SAMs of a rigid molecular tripod consisting of an adamantane core and three CH2SH groups were employed to arrange ferrocene on a gold surface through oligo(p-phenyleneethynylene) linkers. Cyclic voltammetry of the monolayers demonstrated high surface coverage of ferrocene, yet the molecular interaction among adjacent ferrocene units was negligible. This was because of the extended intermolecular distance caused by the bulky tripod framework. The rates of electron transfer from the ferrocene to the gold surface through different linker lengths were determined by electrochemical measurements, from which the decay factor for oligo(p-phenyleneethynylene) wire was evaluated.
17
Tunlid, Anders, Bruce H. Baird, Melanie B. Trexler, Stefan Olsson, Robert H. Findlay, Goran Odham, and David C. White. "Determination of phospholipid ester-linked fatty acids and poly β-hydroxybutyrate for the estimation of bacterial biomass and activity in the rhizosphere of the rape plant Brassica napus (L.)." Canadian Journal of Microbiology 31, no. 12 (December 1, 1985): 1113–19. http://dx.doi.org/10.1139/m85-210.
Abstract:
Examination of seven strains of gram-negative bacteria isolated from the rhizosphere of the rape plant showed profiles of fatty acids, ester-linked to their phospholipids that were distinctly different from sterile roots. The bacteria were enriched in short and branched saturated, cyclopropane and monoenoic fatty acids in which the unsaturation was formed by the anerobic desaturase pathway when growth was on a medium simulating root exudates. This suite of fatty acids was significantly increased in sand and in roots of rape plants grown from seeds in sands inoculated with these organisms at the start of the experiments. Some of the bacteria formed the endogenous storage polymer poly β-hydroxybutyrate in monocultures. Poly β-hydroxybutyrate was formed by the bacteria in the inoculated sand in large amounts but not by the bacteria that were recovered from the roots. This suggests that bacteria associated with the roots were in balanced growth, whereas the bacteria in the sand were lacking essential nutrients and showed an unbalanced growth response. These chemical analyses provided estimates of the bacterial biomass (from the sum of bacterial ester-linked phospholipid fatty acids) and the metabolic status (poly β-hydroxybutyrate to phospholipid fatty acid ratio) in this experiment. With further definition of lipid biomarkers of soil microorganisms these experimental techniques may be extended to the rhizosphere.
18
Benson, Craig H., Michael A. Olson, and Wayne R. Bergstrom. "Temperatures of Insulated Landfill Liner." Transportation Research Record: Journal of the Transportation Research Board 1534, no. 1 (January 1996): 24–31. http://dx.doi.org/10.1177/0361198196153400105.
Abstract:
Five methods for insulating the side slope of a landfill liner were evaluated in a field test. The insulations consisted of leachate collection sand, leachate collection sand and chipped tires, polyurea foam, polystyrene boards, and encapsulated fiberglass geoinsulation panels. Results of the study indicated that tire chips are an effective means of insulating landfill liners, whereas sand alone is inadequate. Of the three geoinsulations tested, the encapsulated fiberglass and extruded polystyrene worked best. The polyurea foam performed poorly, although its performance would have been better had it been thicker. The results of the study also indicated that freezing of the liner can occur near gaps between geoinsulation panels and at corners where the panels are joined if the overlaps or seaming methods are inadequate.
19
Tian, Jun, Thomas A. P. Seery, Derek L. Ho, and R. A. Weiss. "Physically Cross-Linked Alkylacrylamide Hydrogels: A SANS Analysis of the Microstructure." Macromolecules 37, no. 26 (December 2004): 10001–8. http://dx.doi.org/10.1021/ma049474z.
20
Carneiro, Lionel, and Corinne Leloup. "Mens sana in corpore sano: Does the Glycemic Index Have a Role to Play?" Nutrients 12, no. 10 (September 29, 2020): 2989. http://dx.doi.org/10.3390/nu12102989.
Abstract:
Although diet interventions are mostly related to metabolic disorders, nowadays they are used in a wide variety of pathologies. From diabetes and obesity to cardiovascular diseases, to cancer or neurological disorders and stroke, nutritional recommendations are applied to almost all diseases. Among such disorders, metabolic disturbances and brain function and/or diseases have recently been shown to be linked. Indeed, numerous neurological functions are often associated with perturbations of whole-body energy homeostasis. In this regard, specific diets are used in various neurological conditions, such as epilepsy, stroke, or seizure recovery. In addition, Alzheimer’s disease and Autism Spectrum Disorders are also considered to be putatively improved by diet interventions. Glycemic index diets are a novel developed indicator expected to anticipate the changes in blood glucose induced by specific foods and how they can affect various physiological functions. Several results have provided indications of the efficiency of low-glycemic index diets in weight management and insulin sensitivity, but also cognitive function, epilepsy treatment, stroke, and neurodegenerative diseases. Overall, studies involving the glycemic index can provide new insights into the relationship between energy homeostasis regulation and brain function or related disorders. Therefore, in this review, we will summarize the main evidence on glycemic index involvement in brain mechanisms of energy homeostasis regulation.
21
Chapuis, Robert P. "Sand–bentonite liners: predicting permeability from laboratory tests." Canadian Geotechnical Journal 27, no. 1 (February 1, 1990): 47–57. http://dx.doi.org/10.1139/t90-005.
Abstract:
Soil–bentonite mixes are frequently used as impervious blankets in waste disposal projects. Numerous results of laboratory permeability tests are presented for sands containing up to 33% bentonite. These results seem difficult to analyze because different testing methods have been used in which it is not easy to control certain parameters, such as hydration period, degree of saturation, and swelling under low confining pressure. Hydraulic conductivity, however, can be obtained by using empirical equations that take into account the bentonite content, porosity, and degree of saturation of the sand alone when tested at its optimum modified Proctor value in a permeameter. This preliminary evaluation helps to select the soil to be tested. Then, the laboratory test results can be used to predict the in situ hydraulic performance after due consideration of the variabilities in natural sand and bentonite content. Key words: liner, soil, bentonite, permeability, laboratory, field.
22
Paumard, Victorien, Julien Bourget, Tobi Payenberg, Annette D. George, R. Bruce Ainsworth, Simon Lang, and Henry W. Posamentier. "Controls On Deep-Water Sand Delivery Beyond the Shelf Edge: Accommodation, Sediment Supply, and Deltaic Process Regime." Journal of Sedimentary Research 90, no. 1 (January 29, 2020): 104–30. http://dx.doi.org/10.2110/jsr.2020.2.
Abstract:
ABSTRACT Stratigraphic models typically predict accumulation of deep-water sands where coeval shelf-edge deltas are developed in reduced-accommodation and/or high-sediment-supply settings. On seismic data, these relationships are commonly investigated on a small number of clinothems, with a limited control on their lateral variability. Advanced full-volume seismic interpretation methods now offer the opportunity to identify high-order (i.e., 4th to 5th) seismic sequences (i.e., clinothems) and to evaluate the controls on shelf-to-basin sediment transfer mechanisms and deep-water sand accumulation at these high-frequency scales. This study focuses on the Lower Barrow Group (LBG), a shelf margin that prograded in the Northern Carnarvon Basin (North West Shelf, Australia) during the Early Cretaceous. Thanks to high-resolution 3D seismic data, 30 clinothems (average time span of ∼ 47,000 years) from the D. lobispinosum interval (142.3–140.9 Ma) are used to establish quantitative and statistical relationships between the shelf-margin architecture, paleoshoreline processes, and deep-water system types (i.e., quantitative 3D seismic stratigraphy). The results confirm that low values of rate of accommodation/rate of sediment supply (δA/δS) conditions on the shelf are associated with sediment bypass, whereas high δA/δS conditions are linked to increasing sediment storage on the shelf. However, coastal process regimes at the shelf edge play a more important role in the behavior of deep-water sand delivery. Fluvial-dominated coastlines are typically associated with steep slope gradients and more mature, longer run-out turbidite systems. In contrast, wave-dominated shorelines are linked to gentle slope gradients, with limited development of turbidite systems (except rare sheet sands and mass-transport deposits), where longshore drift currents contributed to shelf-margin accretion through the formation of extensive strandplains. In this context, reduced volumes of sand were transported offshore and mud belts were accumulated locally. This study highlights that variations from fluvial- to wave-dominated systems can result in significant lateral changes in shelf-margin architecture (i.e., slope gradient) and impact the coeval development of deep-water systems (i.e., architectural maturity). By integrating advanced tools in seismic interpretation, quantitative 3D seismic stratigraphy represents a novel approach in assessing at high resolution the controls on deep-water sand delivery, and potentially predicting the type and location of reservoirs in deep water based on the shelf-margin architecture and depositional process regime.
23
Paladini, Giuseppe, Valentina Venuti, László Almásy, Lucio Melone, Vincenza Crupi, Domenico Majolino, Nadia Pastori, Andrea Fiorati, and Carlo Punta. "Cross-linked cellulose nano-sponges: a small angle neutron scattering (SANS) study." Cellulose 26, no. 17 (September 7, 2019): 9005–19. http://dx.doi.org/10.1007/s10570-019-02732-2.
24
Liu, Guang Yan, and Wen Cai Wang. "XPS Characterization of Porphyrin Based Self-Assembled Monolayers on Gold." Advanced Materials Research 548 (July 2012): 234–38. http://dx.doi.org/10.4028/www.scientific.net/amr.548.234.
Abstract:
XPS characterization of self-assembled monolayers (SAMs) of tetraphenylporphyrin bearing a rigid tripodal linker by chemisorption of the thiol-derivatized terminal groups on gold substrate is described. The surface structure of the SAMs bearing tripodal linker were analyzed by X-ray photoelectron spectroscopy (XPS), and electrochemical cyclic voltammetry (CV) measurements. XPS confirms the formation of porphyrin SAMs on Au surface and identified bonding configurations of porphyrin molecules in the chemisorption of SAMs. The film thickness values (36 Å) obtained by XPS agree well with the estimated value by assuming the vertical orientation of the molecules on the gold surface. Using the Au4f7/2 as an internal standard, a lower binding energies shift (1.8 eV) of S2p in the SAMs reveals that the porphyrins were chemisorbed onto the surface via sulfurgold bonds. Electrochemical CV measurements suggest near monolayer coverage of the tripodal porphyrins with good stability of the redox SAMs, which have promising application in the development of molecular based electronic device and memory architectures.
25
Rout, Suryaleen, and Suresh Prasad Singh. "Characterization of pond ash-bentonite mixes as landfill liner material." Waste Management & Research: The Journal for a Sustainable Circular Economy 38, no. 12 (April 28, 2020): 1420–28. http://dx.doi.org/10.1177/0734242x20918013.
Abstract:
Characterization of pond ash-bentonite mixes is made to assess their suitability as liner material for waste disposal facilities by examining the relevant index and engineering properties. Further, a comparative assessment is made between sand-bentonite and pond ash-bentonite mixes for the range of bentonite content varying from 0 to 30% by weight at an interval of 5% to ensure an effective substitution of sand with pond ash. Addition of bentonite to sand or pond ash significantly influences the plasticity, strength and permeability properties. Besides, the shape parameters of the coarser fraction and morphology of compacted mixes also influence the engineering properties. A multiple linear regression equation is suggested to predict the hydraulic conductivity of these mixes by considering the basic material properties such as liquid limit, plasticity index and void ratio as an input variable with a correlation coefficient of 0.92 between the measured and predicted hydraulic conductivity values. At comparable conditions, compacted pond ash-bentonite mixes exhibit higher strength but also higher permeability than sand-bentonite mixes. Pond ash-bentonite and sand-bentonite mixes met the liner requirements when compacted with modified Proctor compaction effort at a minimum bentonite content of 20% and 15%, respectively.
26
Bolívar-Anillo, Hernando José, Zamira E. Soto-Varela, Hernando Sánchez Sánchez Moreno, Diego Andrés Villate Daza, David Rosado-Porto, Shersy Vega Vega Benites, Camila Pichón Pichón González, and Giorgio Anfuso. "A Preliminary Approximation to Microbiological Beach Sand Quality along the Coast of the Department of Atlántico (Caribbean Sea of Colombia): Influence of the Magdalena River." Water 15, no. 1 (December 23, 2022): 48. http://dx.doi.org/10.3390/w15010048.
Abstract:
Beaches represent important economic resources linked to “Sun, Sea and Sand” tourism and, therefore, their water quality constitutes an issue of great relevance especially in developing countries. The main objective of this work was to determine the microbial quality of beach sediments along the Caribbean coast of the Department of Atlántico (Colombia) and its relationships with the existence of local sources of contamination (e.g., streams containing wastewaters), beach exposition to waves, the quantity of beach visitors—which is reflected by beach typology (e.g., urban, rural, etc.), the presence of tourist activities/infrastructures and the beach sand sedimentological characteristics. Along the study area, samples of beach sediments were gathered in beach face and backshore areas at 11 sectors and the microbiological counts of three faecal indicator bacteria, i.e., Escherichia coli, Enterococcus spp. and Clostridium perfringens, were determined. A homogeneous distribution was recorded along the coast of Escherichia coli and Clostridium perfringens in both beach face and backshore sediments, in the order of 5 and 2 log CFU/100 mL, respectively; Enterococcus spp. was, at places, not observed in backshore sediments. No relationships existed between, on one side, the counts of the faecal indicator bacteria considered and, on the other side, the presence of streams and tourist activities/infrastructures, beach typology, exposition to waves and the sedimentological characteristics of beach sands. Such results suggest a chronic contamination of beach face and backshore sediments linked to the heavily polluted sedimentological load of the Magdalena River.
27
Iliasov, Leonid, Andrey Shibaev, Irina Panova, Petr Kushchev, Olga Philippova, and Alexander Yaroslavov. "Weakly Cross-Linked Anionic Copolymers: Kinetics of Swelling and Water-Retaining Properties of Hydrogels." Polymers 15, no. 15 (July 30, 2023): 3244. http://dx.doi.org/10.3390/polym15153244.
Abstract:
Six cross-linked copolymers consisting of sodium acrylate, N-acrylamide, starch fragments and a cross-linker were synthesized, potentially suitable for use in agriculture as superabsorbents. The copolymers had the same content of carboxyl groups equal to 6.2 mmoles per 1 g of copolymer and the content of cross-linker (Q) varied from 0.04 up to 1 wt.%. The copolymers swelled in a pH 6.5 aqueous buffer solution thus giving hydrogel particles, which were characterized by a set of methods including gravimetry, rheometry, swelling pressure analysis, equilibrium centrifugation and water retention analysis with the following main conclusions. An increase in Q decreases the equilibrium degree of swelling. When swelling in a solid substrate, sand or soil, the equilibrium degree of swelling shows the maximum at Q = 0.14 wt.%. The cross-linking degree controls the swelling pressure of hydrogels and water-retaining properties of solid substrates with embedded hydrogels; in both cases, the maximum effects are observed at Q = 0.14 wt.%. These extreme dependences set the algorithm for synthesis of polymeric superabsorbents and optimization of their operational characteristics.
28
Guo, Yujia, Alireza Nouri, and Siavash Nejadi. "Effect of Slot Width and Density on Slotted Liner Performance in SAGD Operations." Energies 13, no. 1 (January 5, 2020): 268. http://dx.doi.org/10.3390/en13010268.
Abstract:
Sand production from a poorly consolidated reservoir could give rise to some severe problems during production. Holding the load bearing solids in place is the main goal of any sand control technique. The only sand control techniques that have found applications in steam assisted gravity drainage (SAGD) are some of the mechanical methods, including wire wrapped screens, slotted liners and more recently, punched screens. Slotted liner is one of the most effective mechanical sand control methods in the unconsolidated reservoir exploitation, which has proven to be the preferred sand control method in the SAGD operations. The main advantage of the slotted liners that makes them suitable for SAGD operations is their superior mechanical integrity for the completion of long horizontal wells. This study is an attempt to increase the existing understanding of the fines migration, sand production, and plugging tendency for slotted liners by using a novel large-scale scaled completion test (SCT) facility. A triaxial cell assembly was used to load sand-packs with specified and controlled grain size distribution, shape and mineralogy, on multi-slot sand control coupons. Different stress levels were applied parallel and perpendicular to different combinations of slot width and density in multi-slot coupons, while brine was injected from the top of the sand-pack towards the coupon. At each stress level, the mass of produced sand was measured, and the pressure drops along the sand-pack and coupon were recorded. Fines migration was also investigated by measuring fines/clay concentration along the sand-pack. The current study employed multi-slot coupons to investigate flow interactions among slots and its effect on the flow performance of liner under typically encountered stresses in SAGD wells. According to the experimental observations, increasing slot width generally reduces the possibility of pore plugging caused by fines migration. However, there is a limit for slot aperture beyond which the plugging is not reduced any further, and only a higher level of sanding occurs. Test measurements also indicated that besides the slot width, the slot density also influences the level of plugging and sand production and must be included in the design criteria.
29
Al-Rawas, Amer A., Yahia E.-A. Mohamedzein, Abdulaziz S. Al-Shabibi, and Salem Al-Katheiri. "Sand–Attapulgite Clay Mixtures as a Landfill Liner." Geotechnical and Geological Engineering 24, no. 5 (October 2006): 1365–83. http://dx.doi.org/10.1007/s10706-005-2214-7.
30
Ilyasov, Leonid O., Irina G. Panova, Petr O. Kushchev, Andrey A. Belov, Irina A. Maksimova, Andrey V. Smagin, and Alexander A. Yaroslavov. "Sparsely Cross-Linked Hydrogel with Starch Fragments as a Multifunctional Soil Conditioner." Journal of Composites Science 6, no. 11 (November 8, 2022): 347. http://dx.doi.org/10.3390/jcs6110347.
Abstract:
A sparsely cross-linked copolymer was synthesized, and was composed of acrylic acid, acrylamide, and starch. Swelling of the copolymer in an aqueous solution resulted in the formation of hydrogel particles; this formulation was used as a partially biodegradable soil conditioner. The hydrogel was characterized with the following main conclusions: (a) the degree of copolymer swelling increases from 300 to 550 when altering the pH of the solution from 3 to 9. (b) After mixing with sand and soil, the degree of swelling decreases because of restricted volumes of sand/soil-filled containers and a mechanical resistance from the sand/soil particles. (c) Initial sand and soil additions demonstrate unsatisfactory water-retaining properties; the addition of the hydrogel significantly increases the maximum water capacity, while a substantial part of the water in the hydrogel remains available to plants. (d) Upon deposition of the hydrogel formulation over sand/soil and drying out, a protective coating forms on the surface, composed of hydrogel and sand/soil particles, resistant to wind and water erosion. (e) The starch-containing hydrogel is non-toxic towards bacterial and fungal microorganisms; the latter can utilize the microgel in order to support their own development. The results of the work indicate that cross-linked anionic copolymers are promising for use as combined soil conditioners.
31
Viallefont-Robinet, Bacour, Bouvet, Kheireddine, Ouhssain, Idoughi, Grignon, Munesa, Lemaître, and Rivière. "Contribution to Sandy Site Characterization: Spectro-Directional Signature, Grain Size Distribution and Mineralogy Extracted from Sand Samples." Remote Sensing 11, no. 20 (October 21, 2019): 2446. http://dx.doi.org/10.3390/rs11202446.
Abstract:
The characterization of sands detailed in this paper has been performed in order to support the in-flight radiometric performance assessment of space-borne optical sensors over the so-called Pseudo-Invariant Calibration Sites (PICS). Although the physical properties of PICS surface are fairly stable in time, the signal measured from space varies with the illumination and the viewing geometries. Thus, there is a need to characterize the spectro-directional properties of PICS. This could be done on a broad scale, thanks to multi-spectral multi-directional space-borne sensors such as the POLDER instrument (with old data). However, interpolating or extrapolating the spectro-directional reflectance measured from space to spectral bands of another sensor is not straightforward. The hyperspectral characterization of sand samples collected within or nearby PICS could contribute to a solution. In this context, a set of 31 sand samples was compiled. The BiConical Reflectance Factor (BCRF), linked to Bidirectional Reflectance Distribution Function (BRDF), was measured between 0.4 and 2.5 µm, over a half hemisphere when the amount of sand in the sample was large enough and for only a single fixed angular configuration for small samples. These optical measurements were complemented by grain size distribution measurements and mineralogical analysis and compiled together with previously published measurements in the so-called PICSAND database, freely available online.
32
Kim, Seongjae, and Hocheon Yoo. "Self-Assembled Monolayers: Versatile Uses in Electronic Devices from Gate Dielectrics, Dopants, and Biosensing Linkers." Micromachines 12, no. 5 (May 17, 2021): 565. http://dx.doi.org/10.3390/mi12050565.
Abstract:
Self-assembled monolayers (SAMs), molecular structures consisting of assemblies formed in an ordered monolayer domain, are revisited to introduce their various functions in electronic devices. SAMs have been used as ultrathin gate dielectric layers in low-voltage transistors owing to their molecularly thin nature. In addition to the contribution of SAMs as gate dielectric layers, SAMs contribute to the transistor as a semiconducting active layer. Beyond the transistor components, SAMs have recently been applied in other electronic applications, including as remote doping materials and molecular linkers to anchor target biomarkers. This review comprehensively covers SAM-based electronic devices, focusing on the various applications that utilize the physical and chemical properties of SAMs.
33
Krishnan, Mohan Raj, Wengang Li, and Edreese Housni Alsharaeh. "Cross-linked polymer nanocomposite networks coated nano sand light-weight proppants for hydraulic fracturing applications." Characterization and Application of Nanomaterials 6, no. 2 (November 29, 2023): 3314. http://dx.doi.org/10.24294/can.v6i2.3314.
Abstract:
Three-dimensionally cross-linked polymer nanocomposite networks coated nano sand light-weight proppants (LWPs) were successfully prepared via ball-milling the macro sand and subsequently modifying the resultant nano sand with sequential polymer nanocomposite coating. The modified nano sand proppants had good sphericity and roundness. Thermal analyses showed that the samples can withstand up to 411 ℃. Moreover, the proppant samples’ specific gravity (S.G.) was 1.02–1.10 g/cm3 with excellent water dispersibility. Therefore, cross-linked polymer nanocomposite networks coated nano sand particles can act as potential candidates as water-carrying proppants for hydraulic fracturing operations.
34
Ross, Cynthia M., Edgar Rangel-German, Louis M. Castanier, Philip S. Hara, and Anthony R. Kovscek. "A Laboratory Investigation of Temperature-Induced Sand Consolidation." SPE Journal 11, no. 02 (June 1, 2006): 206–15. http://dx.doi.org/10.2118/92398-pa.
Abstract:
Summary Current gravel-packed, slotted-liner completion techniques for wells in unconsolidated and weakly consolidated sandstone are relatively expensive and result in greatly reduced operational flexibility. On the other hand, empirical field evidence (Wilmington, California) demonstrates that sand grains surrounding the wellbore are cemented and consolidated following injection of high-pressure (1,600-psi) steam. Effective sand control results without adverse changes to formation permeability and producibility. Here, sand consolidation mechanisms are exposed by duplicating, in the laboratory, the governing geochemical processes. Sandpacks contain typical per-volume concentrations of concrete resulting from perforating a cased and cemented well. The evolution of sandpack pore and grain struture is determined using scanning electron microscope imaging and compositional analyses. Results show that hot alkaline water injected at rates comparable to field rates indeed results in grain-cementing precipitates. Casing cement plays a crucial role in that it is the source of calcium silicates appearing in various pore-lining precipitates. Conditions for effective sand consolidation are not necessarily formation-specific, and the process can be altered to improve cost-effectiveness, flexibility, and longevity of the completion technique. Introduction In poorly consolidated and unconsolidated sandstone reservoirs, solids are sometimes carried from the formation to the wellbore as oil and water flow toward producers. It is referred to as "sand production." This term is usually detrimental and should be avoided. Operational problems result, including extra wear of the pumping units, shorter pipe lifetime, frequent workovers, loss of well productivity, and waste-disposal issues. Several remedies are available to the engineer. They include production-rate reduction (Penberthy and Shaughnessy 1992), physical barriers (Penberthy and Shaughnessy 1992), in-situ consolidation (Prats and Hamby 1965; Davies et al. 1983; Davies et al. 1997; Davies et al. 2003), and hybrid methods (Penberthy and Shaughnessy 1992; Kruger 1986). No sand-control method is, as of yet, generally applicable. We use laboratory experiments to develop a mechanistic understanding of a novel hot alkaline/steam sand-consolidation technique. This technique has proved effective empirically (Davies et al. 1997). The mechanisms of mineral and grain dissolution, precipitation, and consolidation using Wilmington (Los Angeles basin, California) field cores and quartz sandpacks are described. Field sands are drawn from the productive, heavy-oil intervals (T and D sands) of the Tar II-A zone (Hara 2003). The tools employed are core-scale and beaker-scale experiments, scanning electron microscopy (SEM), and elemental analyses. Additionally, tubing-tail samples recovered from the field are reexamined in light of the new laboratory results. Before proceeding to the experimental details and results, a brief review of the hot alkaline/steam sand-consolidation process is given. This background is foundational, because it underpins the experimental program and interpretation of results. The experimental objectives, apparatus, and procedures follow. Results, discussion, and implications finish the paper.
35
Yao, Erdong, and Bojun Li. "Low-Cost H-Grade Polyacrylamide Gel with High-Temperature Resistance." Processes 10, no. 6 (June 9, 2022): 1165. http://dx.doi.org/10.3390/pr10061165.
Abstract:
This paper presents a low-cost, high-temperature-resistant and high-strength polyacrylamide gel system formed by secondary cross-linking. The gel system (named JM186) used phenolic resin and organic zirconium as cross-linking agents, and the performance of the gel system was systematically evaluated under high temperature. The gel properties studied include: gel formation time, gel strength, thermal stability, sand-filled pipe sealing efficiency, and its microstructure. The concentration of polyacrylamide in JM186 gel system was as low as 0.3%, which can control the gelling time in a range of 1–9 h by adjusting the ratio of two cross-linking agents. It can resist temperature up to 120 °C without dehydration, and its highest gel strength can reach H grade. The modulus of elasticity (G’) and viscosity (G”) can reach 32.33 Pa and 3.25 Pa, respectively. DSC (differential scanning calorimetry) test indicated that the temperature of structural failure for this composite gel is 310.5 °C. The average sealing efficiency of the gel is 96.03% in sand-filled pipes. Finally, the gel microstructure was observed by cryo-scanning electron microscopy (Cryo-SEM). It was found that the gel system by secondary cross-linking has a dense and thickened network structure compared with the single cross-linker gel system. The gel is cross-linked by both the coordination bond and covalent bond, and the two cross-linking agents have a synergistic effect. This is the reason why the secondary cross-link gel system is better than the single-cross-linker gel system.
36
Gao, Junli, and Jiajun Wang. "Interface Behavior Analysis of Different Geomembrane Liner Systems Based on PIV Techniques." Applied Sciences 13, no. 11 (May 29, 2023): 6614. http://dx.doi.org/10.3390/app13116614.
Abstract:
The interfacial friction performance of the liner system has an important influence on the overall stability of modern landfills, but the interface of the liner system using conventional geomembranes may have problems such as shear failure and slip along the liner system. Accordingly, the concept of a ribbed geomembrane was proposed. Based on the laboratory model tests, the variation laws of p–s curves and the additional stress of sand were studied under different values of shape, rib spacing, and rib height. A series of particle image velocimetry (PIV) analyses of sand particles were performed to provide insight into the reinforcement mechanism of the ribbed geomembrane liner system. The results indicated that the ribbed geomembrane could obviously improve the stability of the liner system compared with the smooth geomembrane. The ribbed geomembrane formed an indirect influence area with sand in a specific range. The ribbed geomembrane with optimal values of rib spacing and rib height was beneficial to reduce the settlement of the upper sand and the stress redistribution of the sand particles.
37
Khamsi, Roxanne. "Concerns over 'shifting sands' linger as genetic testing expands." Nature Medicine 14, no. 6 (June 2008): 589. http://dx.doi.org/10.1038/nm0608-589.
38
Kulhara, Parmanand, and Ajit Avasthi. "Influence of depressive symptoms and premorbid adjustment on factor structure of phenomenology of schizophrenia: a study from India." European Psychiatry 18, no. 5 (August 2003): 226–32. http://dx.doi.org/10.1016/s0924-9338(03)00062-2.
Abstract:
AbstractThis study investigated the nature of factor structure of schizophrenia syndromes using a sample of 151 patients with schizophrenia according to DSM-IV. The patients were assessed on the Scale for the Assessment of Positive Symptoms (SAPS), the Scale for the Assessment of Negative Symptoms (SANS), Hamilton Depression Rating Scale (HDRS) and the Phillips Rating Scale of Premorbid Adjustment in schizophrenia. Three factors—negative syndrome, reality-distortion syndrome and disorganized syndrome were extracted when only SAPS and SANS were analysed. Addition of the Phillips Rating Scale scores to SAPS and SANS ratings in the factorial equation led to splitting of the negative syndrome though reality-distortion and disorganized syndromes remained stable. Factor analysis of the HDRS scores with SAPS and SANS ratings resulted in the HDRS loading highly on reality-distortion syndrome and splitting of negative syndrome. Factor analysis of all the variables taken together resulted in delineation of four factors. The study suggests a link between depression and reality distortion. Apathy and anhedonia seem to be linked to premorbid adjustment.
39
Dickinson, S., and R. W. I. Brachman. "Assessment of alternative protection layers for a geomembrane – geosynthetic clay liner (GM–GCL) composite liner." Canadian Geotechnical Journal 45, no. 11 (November 2008): 1594–610. http://dx.doi.org/10.1139/t08-081.
Abstract:
A protection layer is required above geomembrane (GM) – geosynthetic clay liner (GCL) landfill liners to limit physical damage (GM strains and GCL thinning) from an overlying granular drainage layer. A 150 mm thick layer of sand has been found to provide excellent protection at a vertical pressure of 250 kPa. However, the use of sand may not be practical in many cases. Experimental results are presented where the effectiveness of alternate protection systems above one particular GM–GCL liner were examined with 50 mm coarse gravel at an applied vertical pressure of 250 kPa. A 150 mm thick layer of compacted clay and a 150 mm thick layer of rubber tire shreds with a nonwoven needle-punched geotextile (570 g/m2) were found to limit the geomembrane strains and GCL extrusion to acceptable levels. Layered geotextiles performed much better than single layers of geotextiles. A layered geocomposite, with a thick nonwoven needle-punched geotextile in the middle to provide cushioning and stiffer woven geotextiles on the top and bottom to carry tensile force, was able to limit the short term strain to less than 3%, but it was not able to prevent local thinning of the GCL because of the deformation required to mobilize force in the geotextiles.
40
Tupper, N. P., E. F. Tadiar, D. L. Price, and J. D. S. Goodall. "A REVISED DEPOSITIONAL MODEL FOR EAST SPAR AND ITS IMPACT ON FIELD PERFORMANCE." APPEA Journal 42, no. 1 (2002): 461. http://dx.doi.org/10.1071/aj01025.
Abstract:
The East Spar gas condensate field is located in production licence WA-13-L in the offshore Carnarvon Basin. Production commenced in 1996 with two subsea wells linked to processing facilities on Varanus Island via a multi-phase pipeline. The pressure performance of the field has been significantly different to predevelopment expectations. This prompted a reexamination of the seismic and well data to investigate the potential for alternative reservoir models.Integrated stratigraphic and seismic interpretation reveals that the Barrow Group reservoir sands were deposited within an incised valley of limited lateral extent. Sea level fall instigated erosion of a valley that on transgression was filled with successive fluvial, estuarine and marine sediments. Good quality sands are expected to be limited to this valley, the upper part of which can be mapped on seismic. Poor sand development in East Spar–2ST is consistent with its location at the edge of the incised valley.Before development, the primary production mechanism was expected to be a strong bottom water drive comparable with other Barrow Group fields in the Carnarvon Basin. The revised depositional model, however, and the observed decline in reservoir pressure, indicate that connection to this regional aquifer is limited. This implies that water influx will probably be later, and ultimate recovery higher, than previously anticipated.
41
Neumann, Laurie, Lea Könemund, Valentina Rohnacher, Annemarie Pucci, Hans-Hermann Johannes, and Wolfgang Kowalsky. "A2BC-Type Porphyrin SAM on Gold Surface for Bacteria Detection Applications: Synthesis and Surface Functionalization." Materials 14, no. 8 (April 13, 2021): 1934. http://dx.doi.org/10.3390/ma14081934.
Abstract:
Currently used elaborate technologies for the detection of bacteria can be improved in regard to their time consumption, labor intensity, accuracy and reproducibility. Well-known electrical measurement methods might connect highly sensitive sensing systems with biological requirements. The development of modified sensor surfaces with self-assembled monolayers (SAMs) from functionalized porphyrin for bacteria trapping can lead to a highly sensitive sensor for bacteria detection. Different A2BC-type porphyrin structures were synthesized and examined regarding their optical behavior. We achieved the synthesis of a porphyrin for SAM formation on a gold surface as electrode material. Two possible bio linkers were attached on the opposite meso-position of the porphyrin, which allows the porphyrin to react as a linker on the surface for bacteria trapping. Different porphyrin structures were attached to a gold surface, the SAM formation and the respective coverage was investigated.
42
Bray, Caroline, Raoul Peltier, Hyungsoo Kim, Antonio Mastrangelo, and Sébastien Perrier. "Anionic multiblock core cross-linked star copolymers via RAFT polymerization." Polymer Chemistry 8, no. 36 (2017): 5513–24. http://dx.doi.org/10.1039/c7py01062a.
43
Sahoo, Hiranya, M. Royhan Gani, Nahid D. Gani, Gary J. Hampson, John A. Howell, Joep E. A. Storms, Allard W. Martinius, and Simon J. Buckley. "Predictable patterns in stacking and distribution of channelized fluvial sand bodies linked to channel mobility and avulsion processes." Geology 48, no. 9 (June 1, 2020): 903–7. http://dx.doi.org/10.1130/g47236.1.
Abstract:
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.
44
Dafalla, Muawia. "Effect of Fluid Chemistry on the Consolidation and Hydraulic Conductivity of Sand-Clay Liners." Sustainability 13, no. 20 (October 11, 2021): 11213. http://dx.doi.org/10.3390/su132011213.
Abstract:
The clay swelling potential of sand-clay liners exposed to saline water or specific chemicals can influence their hydraulic conductivity and other consolidation properties. The effect of saline water or chemicals on the sand-clay liners was thus studied and evaluated. The consolidation characteristics of the sand-clay liner can be different when tested under different fluid media. Bentonite and cement grouts are chemicals that have a significant effect on the sand-clay liners. Cement and bentonite can be used to seal off the openings within the liner to repair a defect or a malfunction. In this study, Al-Qatif clay was used to form a sand-clay liner when mixed with fine-grained sand (clay is 20% by dry weight). Soil samples extracted from this liner were exposed to inorganic chemical solutions. NaCl and CaCl2 solutions with concentration ranges of 0.1%, 0.5%, and 1.5% were used. Acidic water with pH values of 4, 5, and 6 was similarly used as fluid media. The effects of NaCl, CaCl2, and water with different acidity on the consolidation characteristics and hydraulic conductivity were obtained and compared to those of the distilled water. The effects of grout materials containing bentonite (1%, 2%, and 3% by weight) and cement (2.5%, 5%, and 7.5% by weight) were also investigated. The addition of bentonite grout to the liner surface was found to improve its hydraulic conductivity. The cement effect on the compressibility was found to be very significant. The findings of this study can serve as a guide for selecting parameters in the design and assessment of sand-clay liners in semi-arid regions and coastal zones.
45
Haughton, Peter D. W., Simon P. Barker, and William D. McCaffrey. "‘Linked’ debrites in sand-rich turbidite systems - origin and significance." Sedimentology 50, no. 3 (June 2003): 459–82. http://dx.doi.org/10.1046/j.1365-3091.2003.00560.x.
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Polito, Carmine P., and James R. Martin. "A Reconciliation of the Effects of Non-Plastic Fines on the Liquefaction Resistance of Sands Reported in the Literature." Earthquake Spectra 19, no. 3 (August 2003): 635–51. http://dx.doi.org/10.1193/1.1597878.
Abstract:
The literature presents several seemingly contradictory reports concerning the effects of non-plastic (i.e., silty) fines content on the liquefaction resistance of sands. These seemingly contradictory trends were reconciled in light of the results of a recent study by the authors that linked cyclic resistance and relative density. It was shown that the trend of decreasing cyclic resistance with increasing silt content reported in the literature could be explained by considering the soil's relative density. The same argument was made for the trend of decreasing and then increasing cyclic resistance with increasing silt content. The concept that cyclic resistance is controlled by the sand skeleton void ratio of the soil was also reconciled with the results of the authors’ previous study. The trend of increasing cyclic resistance (without a corresponding initial decrease) with increasing silt content that has been reported in the literature does not appear to occur in non-plastic silts.
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Sheng, Jack Chih-Chieh, Brian De La Franier, and Michael Thompson. "Assembling Surface Linker Chemistry with Minimization of Non-Specific Adsorption on Biosensor Materials." Materials 14, no. 2 (January 19, 2021): 472. http://dx.doi.org/10.3390/ma14020472.
Abstract:
The operation of biosensors requires surfaces that are both highly specific towards the target analyte and that are minimally subject to fouling by species present in a biological fluid. In this work, we further examined the thiosulfonate-based linker in order to construct robust and durable self-assembling monolayers (SAMs) onto hydroxylated surfaces such as silica. These SAMs are capable of the chemoselective immobilization of thiol-containing probes (for analytes) under aqueous conditions in a single, straightforward, reliable, and coupling-free manner. The efficacy of the method was assessed through implementation as a biosensing interface for an ultra-high frequency acoustic wave device dedicated to the detection of avidin via attached biotin. Fouling was assessed via introduction of interfering bovine serum albumin (BSA), IgG antibody, or goat serum. Improvements were investigated systematically through the incorporation of an oligoethylene glycol backbone employed together with a self-assembling diluent without a functional distal group. This work demonstrates that the incorporation of a diluent of relatively short length is crucial for the reduction of fouling. Included in this work is a comparison of the surface attachment of the linker to Si3N4 and AlN, both materials used in sensor technology.
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Qu, Wen Tao, Yi Xiao Guo, Tao Ren, and Yan Ping Sun. "Structure Optimization and Strength Analysis of CBM Special Anti-Clogging Drainage Pump." Advanced Materials Research 479-481 (February 2012): 2017–21. http://dx.doi.org/10.4028/www.scientific.net/amr.479-481.2017.
Abstract:
There are abundant coal bed methane resources in China, and recovery technology is considered a very important part in the development of coal bed methane. At present, coal bed methane production areas are still adopting the tubing liner pump, but because of the special working environment, in the pumping process, the fine breeze (sand) and other solid particles entering into the pump barrel is likely to cause the pump stuck, pipe string buried by sand and other issues. In view of the above problems, based on the ordinary tubing liner pump, through the increase of the anti-litter bypass style traveling valve housing and fixed valve housing, outside liner jacket, sand reservoir and liquid in tee joint measures we developed a new type of CBM special anti-clogging drainage pump and adopted finite element analysis software ANSYS to complete key parts of strength calculation. The use of this pump will effectively reduces the blocking of fine coal particles (sand) and other solid particles, decreases the pump's checking operation and workload of sand bailing, consequently improves efficiency, reduces overall operating costs.
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Bennett, Matthew R., David Huddart, and Richard I. Waller. "Glaciofluvial crevasse and conduit fills as indicators of supraglacial dewatering during a surge, Skeiðarárjökull, Iceland." Journal of Glaciology 46, no. 152 (2000): 25–34. http://dx.doi.org/10.3189/172756500781833232.
Abstract:
AbstractThis paper documents the glaciological structures associated with the surge of Skeiðarárjökull, Iceland, in 1991. These structures are interpreted as units of stratified ice, low-angle fractures, vertical and sub-vertical fractures (crevasse traces) and thrusts. The inferred thrusts are debris-rich and, unusually, have both down-glacier and up-glacier dips close to the ice margin. Sediment infills consist of either massive sand or horizontally stratified sand units. The most significant debris-rich structures on the glacier surface, however, are supraglacial crevasse and conduit fills, which contain either massive or horizontally stratified silts, sands and granule-gravels. These sediments infill both vertical fractures (relict crevasses) and englacial conduits. At the stratigraphic base of these sediment fills there is evidence of syn-sedimentary deformation, suggesting that sedimentation occurred during crevasse closure and continued thereafter. We argue that these structures relate to an episode of supraglacial meltwater flow during the 1991 surge, caused by the build-up of subglacial water pressure in a linked-cavity system or some similar distributed drainage system beneath the glacier. The development of this high-level drainage route may have helped regulate basal water pressures and therefore the active phase of the surge. The idea that the supraglacial leakage of subglacial water may have played a role in terminating the surge is explored.
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Lin, Mei Qin, Jin Ru Guo, Feng Qiang Xu, Gui Qing Zhang, Ming Yuan Li, and Bo Peng. "Study on the Matching between Cross-Linked Polymer Microspheres and Nuclear-Pore Membranes." Advanced Materials Research 160-162 (November 2010): 1346–53. http://dx.doi.org/10.4028/www.scientific.net/amr.160-162.1346.
Abstract:
The shape and size of the linked polymer microspheres and the matching between the microsphere size and nuclear-pore membranes were studied in this paper. Scanning electron microscopy(SEM), microscope, dynamic lighting scattering(DLS), Laser diffracting measurements, nuclear-pore film filtration and sand packed tube displacement experiment was adopted for investigation. The results showed that the original shape of the microspheres is typically spherical with a size range of 400-5000nm. When the microspheres were dispersed in water, swelling occurred, resulting in larger size but spherical conformation remained. And the system was poly-dispersed. There are certain matching relationships between the microsphere size and the membranes pore size, and the best plugging property could only occur when they are well-matched. Matching relationships also exist in the sand packed tube displacement experiment, when sand packed tubes with low permeability were used, plugging could occur effectively, and well in-depth plugging could happen as well.