Investigation into the hygrothermal behavior of fired clay materials during the freezing of supercooled water using experiments and numerical simulations

2021 ◽  
pp. 174425912110411
Author(s):  
Kazuma Fukui ◽  
Chiemi Iba ◽  
Madoka Taniguchi ◽  
Kouichi Takahashi ◽  
Daisuke Ogura
Keyword(s):  
Surface Area ◽  
Water Saturation ◽  
Supercooled Water ◽  
Clay Material ◽  
Experimental Conditions ◽  
Cooling Rates ◽  
Freezing Points ◽  
Hygrothermal Behavior ◽  
Short Period ◽  
Clay Materials

In this study, supercooling effects on the hygrothermal behavior of fired clay materials under various experimental conditions, such as water content, cooling rates, and size of specimens were investigated using experimental methods and hygrothermal simulations. We report results of the differential scanning calorimetry (DSC) and temperature distribution changes during a freeze–thaw (FT) experiment using unsaturated specimens. Also, we developed a numerical model of the freezing and thawing processes including the supercooling processes. The DSC results show the freezing of the supercooled water in a fired clay material is considerably faster than that in cement-based materials. It was also found that the dependency of the supercooling effects on the cooling rates seemed to be small. When the water saturation of a material decreases, the rate of the ice saturation increase during the freezing of the supercooled water is decreased while the freezing points of the supercooled water was not changed considerably. The comparison of the results of the FT experiment and hygrothermal simulations show that the combination of the existed hygrothermal model and a modified kinetic equation can reproduce the rapid temperature rise during the freezing of the supercooling water in the FT experiment. Finally, the size effects of specimens on the supercooling phenomenon was discussed based on the experimental and calculation results. The freezing points got higher when a specimen was larger. Due to differences in the ratio of the surface area to the volume, hygrothermal behavior in small specimens and relatively large specimens like that of the DSC and the FT experiment, respectively were markedly different. Water in a relatively large specimen with a small ratio of surface area to volume can achieve the thermodynamic equilibrium in a short period after the freezing starts.

scholarly journals Towards Control of the Size, Composition and Surface Area of NiO Nanostructures by Sn Doping

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 444
Author(s):  
María Taeño ◽  
David Maestre ◽  
Julio Ramírez-Castellanos ◽  
Shaohui Li ◽  
Pooi See Lee ◽  
...  
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Size Composition ◽  
Charge Compensation ◽  
Potential Candidate ◽  
Sno2 Nanostructures ◽  
Experimental Conditions ◽  
Sn Doping ◽  
Compensation Mechanisms

Achieving nanostructures with high surface area is one of the most challenging tasks as this metric usually plays a key role in technological applications, such as energy storage, gas sensing or photocatalysis, fields in which NiO is gaining increasing attention recently. Furthermore, the advent of modern NiO-based devices can take advantage of a deeper knowledge of the doping process in NiO, and the fabrication of p-n heterojunctions. By controlling experimental conditions such as dopant concentration, reaction time, temperature or pH, NiO morphology and doping mechanisms can be modulated. In this work, undoped and Sn doped nanoparticles and NiO/SnO2 nanostructures with high surface areas were obtained as a result of Sn incorporation. We demonstrate that Sn incorporation leads to the formation of nanosticks morphology, not previously observed for undoped NiO, promoting p-n heterostructures. Consequently, a surface area value around 340 m2/g was obtained for NiO nanoparticles with 4.7 at.% of Sn, which is nearly nine times higher than that of undoped NiO. The presence of Sn with different oxidation states and variable Ni3+/Ni2+ ratio as a function of the Sn content were also verified by XPS, suggesting a combination of two charge compensation mechanisms (electronic and ionic) for the substitution of Ni2+ by Sn4+. These results make Sn doped NiO nanostructures a potential candidate for a high number of technological applications, in which implementations can be achieved in the form of NiO–SnO2 p-n heterostructures.

Pre-clinical laboratory evaluation of the new ‘AF’ arterial line filter range

Perfusion ◽  
2010 ◽  
Vol 25 (4) ◽  
pp. 267-276 ◽  
Author(s):  
Gemma Yarham ◽  
John Mulholland
Keyword(s):  
Pressure Drop ◽  
Surface Area ◽  
Heart Surgery ◽  
Clinical Laboratory ◽  
Open Heart Surgery ◽  
Global Market ◽  
Individual Characteristics ◽  
Laboratory Evaluation ◽  
Arterial Line ◽  
Experimental Conditions

Introduction: The presence of emboli was recognised relatively early in the history of open heart surgery. The emboli produced during cardiopulmonary bypass have the predisposition to distribute into, and ultimately obstruct, microvessels of all tissues. The Sorin Group has recently developed a new range of arterial line filters. Before the Sorin AF range of filters was released for pre-launch clinical trials, our group performed in vitro laboratory testing of the AF range against a selection of commercially available filters on the global market. Results: The Sorin AF620 and AF640 demonstrate both the smallest prime volume and smallest surface contact area (92ml and 290cm2, respectively).The results of the GME Handling Efficiency experiments ranged by 39.6%, from 95.9% to 56.3%. In terms of an air bolus handling, the results of the Limit Bolus experiment ranged by 97ml, from 147.5ml down to 50ml. The pressure drop across all the filters was measured under steady state experimental conditions. All of the above investigations were considered against surface area and prime volume. Conclusion: It is clear from the results that some commercially available arterial line filters perform better than others, not only in overall performance, but also with regard to individual characteristics. Evaluating arterial line filters for hospital-specific use has to balance pressure drop, surface area, micro air handling, prime volume and gross air handling; all points need to be considered. In the AF620 and AF640, Sorin boast that they are the two smallest prime and smallest surface area filters commercially available on the global market. The Sorin AF filter range performs well in all of the areas we investigated and will be a competitive option for centres, irrespective of which characteristics they use to evaluate and select their arterial line filter.

Homeopathy in parasitic diseases

2021 ◽  
Vol 11 (40) ◽  
pp. 168-169
Author(s):  
Denise Lessa Aleixo ◽  
Leoni Vilano Bonamin ◽  
Silvana Marques De Araujo
Keyword(s):  
Basic Research ◽  
Farm Animals ◽  
Parasitic Infections ◽  
Experimental Conditions ◽  
Traditional Medicines ◽  
Short Period ◽  
Experimental Parameters ◽  
Daily Dose ◽  
Sanitary Conditions ◽  
Main Effects

Introduction: The use of homeopathic medicines has increased, once traditional medicines sometimes do not produce the desired effects and because side effects sometimes compromise the treatment. In recent years, research on homeopathy has clearly developed, both in the implementation of more consistent methodologies and in the description of the data and published methods, improvement are still required in these matters. The acknowledgment of homeopathy depends on the credibility of the groups researching this topic Objective: list and criticize articles highlighting main effects, schedule of treatment and potencies used in different animals models. Material and Methods: A review of articles published since 2000 in journals indexed in the PubMed/Scielo databases was performed. Keywords used were parasitosis/homeopathy and parasitosis/ultra-diluted, in English and Portuguese. Specialized journals such as Homeopathy, International Journal of High Dilution Research, and Brazilian Homeopathic Journal were also used. The contents of each issue of these journals were examined for the "Use of highly diluted medication in parasitic infections." Results and Discussion: Thirty nine papers have been gathered. The methodology of the articles surveyed did not meet the requirements listed in the REHBaR[1]. Thirty seven reports have shown the benefits/effects of highly diluted medicine in the treatment of infectious diseases. In models where experimental conditions are carefully controlled, the conclusions follow the same pattern as those observed in the treatment of farm animals, where, even without completely controlled conditions, clinical result is positive. In fourteen reports using the same model, eight where animals were treated in a constant and prolonged way shown a better result, compared with six reports in which animals were treated for a short period of time, receiving a single daily dose. Several authors have conducted clinical trials using commercial formulas, which do not always provide their composition and/or dynamization, making it difficult to reproducing the experiment. In some of the articles, it was not mentioned if the experiments were repeated at least twice. Conclusions: In parasitic infections, the effect of homeopathic medications is still controversial, and the experimental parameters for evaluation shoud be carefully chosen to avoid isolated analyses of data. Researchers should consider results regarding environmental and sanitary conditions of the animal as a whole. The improvement of techniques and expansion of knowledge about highly diluted medicines may lead to a viable alternative to treat parasitic infections. Precise and detailed descriptions will contribute to advances in the use of homeopathy, so that the wider community can benefit, in practice, from these findings. Keywords: homeopathy, parasitic infections, CAM (Complementary and Alternative Medicine). Reference [1] Lüdtke R, Musial F, Wijk R, Witt C, Baumgartner S. Reporting experiments in homeopathic basic research (REHBaR) – A detailed guideline for authors. Homeopathy. 2009; 98:287-298.

scholarly journals Adsorption of pharmaceuticals from aqueous solutions using biochar derived from cotton gin waste and guayule bagasse

Biochar ◽  
2020 ◽  
Author(s):  
Marlene C. Ndoun ◽  
Herschel A. Elliott ◽  
Heather E. Preisendanz ◽  
Clinton F. Williams ◽  
Allan Knopf ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Specific Surface Area ◽  
High Surface ◽  
Strong Interactions ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Cotton Gin Waste ◽  
Cotton Gin

Abstract Biochars produced from cotton gin waste (CG) and guayule bagasse (GB) were characterized and explored as potential adsorbents for the removal of pharmaceuticals (sulfapyridine-SPY, docusate-DCT and erythromycin-ETM) from aqueous solution. An increase in biochar pyrolysis temperature from 350 οC to 700 οC led to an increase in pH, specific surface area, and surface hydrophobicity. The electronegative surface of all tested biochars indicated that non-Coulombic mechanisms were involved in adsorption of the anionic or uncharged pharmaceuticals under experimental conditions. The adsorption capacities of Sulfapyridine (SPY), Docusate (DCT) and Erythromycin (ETM) on biochar were influenced by the contact time and solution pH, as well as biochar specific surface area and functional groups. Adsorption of these pharmaceutical compounds was dominated by a complex interplay of three mechanisms: hydrophobic partitioning, hydrogen bonding and π–π electron donor–acceptor (EDA) interactions. Despite weaker π–π EDA interactions, reduced hydrophobicity of SPY− and increased electrostatic repulsion between anionic SPY− and the electronegative CG biochar surface at higher pH, the adsorption of SPY unexpectedly increased from 40% to 70% with an increase in pH from 7 to 10. Under alkaline conditions, adsorption was dominated by the formation of strong negative charge-assisted H-bonding between the sulfonamide moiety of SPY and surface carboxylic groups. There seemed to be no appreciable and consistent differences in the extent of DCT and ETM adsorption as the pH changed. Results suggest the CG and GB biochars could act as effective adsorbents for the removal of pharmaceuticals from reclaimed water prior to irrigation. High surface area biochars with physico-chemical properties (e.g., presence of functional groups, high cation and anion exchange capacities) conducive to strong interactions with polar-nonpolar functionality of pharmaceuticals could be used to achieve significant contaminant removal from water. Graphic Abstract

Studies on milk yield and calf suckling behaviour in Kenyan camels (Camelus dromedarius)

1996 ◽  
Vol 1996 ◽  
pp. 105-105 ◽  
Author(s):  
S.P. Simpkin ◽  
P. Rowlinson
Keyword(s):  
Milk Yield ◽  
Literature Survey ◽  
Camel Milk ◽  
Human Consumption ◽  
Milk Secretion ◽  
Experimental Conditions ◽  
Short Period ◽  
The World ◽  
Total Milk ◽  
Milking Frequency

Estimates of camel lactation yields in the literature vary from less than 1000kg to more than 12000 kg, with mean daily yields from 0.1 to 35kg (Simpkin 1985). Suckling or milking frequency and strength of the milk letdown reflex are just two of many factors that affect milk secretion rate in camels. Most of the 18 million camels in the world are kept in nomadic pastoral herds where estimation of milk yield is particularly difficult and the large variation in reported camel milk yields could be attributed to the methodology used to estimate yields. A literature survey shows most articles are based on infrequent observations on small numbers of animals over a short period of lactation and fail to state the experimental conditions or whether figures represent milk offtake for human consumption or total milk yield.

The Characteristics and Impacts Factors of Relative Permeability Curves in High Temperature and Low-Permeability Limestone Reservoirs

2014 ◽  
Vol 1010-1012 ◽  
pp. 1676-1683 ◽  
Author(s):  
Bin Li ◽  
Wan Fen Pu ◽  
Ke Xing Li ◽  
Hu Jia ◽  
Ke Yu Wang ◽  
...  
Keyword(s):  
Relative Permeability ◽  
Oil Recovery ◽  
Water Saturation ◽  
Phase Region ◽  
Two Phase ◽  
Experimental Conditions ◽  
Irreducible Water Saturation ◽  
Productive Water ◽  
Relative Permeability Curves ◽  
Water Cut

To improve the understanding of the influence of effective permeability, reservoir temperature and oil-water viscosity on relative permeability and oil recovery factor, core displacement experiments had been performed under several experimental conditions. Core samples used in every test were natural cores that came from Halfaya oilfield while formation fluids were simulated oil and water prepared based on analyze data of actual oil and productive water. Results from the experiments indicated that the shape of relative permeability curves, irreducible water saturation, residual oil saturation, width of two-phase region and position of isotonic point were all affected by these factors. Besides, oil recovery and water cut were also related closely to permeability, temperature and viscosity ratio.

scholarly journals An Empirical Parameterization of Heterogeneous Ice Nucleation for Multiple Chemical Species of Aerosol

2008 ◽  
Vol 65 (9) ◽  
pp. 2757-2783 ◽  
Author(s):  
Vaughan T. J. Phillips ◽  
Paul J. DeMott ◽  
Constantin Andronache
Keyword(s):  
Surface Area ◽  
Heterogeneous Nucleation ◽  
Large Scale ◽  
Water Saturation ◽  
Chemical Species ◽  
Spectral Width ◽  
Diffusion Chamber ◽  
Field Studies ◽  
Cloud Models ◽  
Multiple Species

Abstract A novel, flexible framework is proposed for parameterizing the heterogeneous nucleation of ice within clouds. It has empirically derived dependencies on the chemistry and surface area of multiple species of ice nucleus (IN) aerosols. Effects from variability in mean size, spectral width, and mass loading of aerosols are represented via their influences on surface area. The parameterization is intended for application in large-scale atmospheric and cloud models that can predict 1) the supersaturation of water vapor, which requires a representation of vertical velocity on the cloud scale, and 2) concentrations of a variety of insoluble aerosol species. Observational data constraining the parameterization are principally from coincident field studies of IN activity and insoluble aerosol in the troposphere. The continuous flow diffusion chamber (CFDC) was deployed. Aerosol species are grouped by the parameterization into three basic types: dust and metallic compounds, inorganic black carbon, and insoluble organic aerosols. Further field observations inform the partitioning of measured IN concentrations among these basic groups of aerosol. The scarcity of heterogeneous nucleation, observed at humidities well below water saturation for warm subzero temperatures, is represented. Conventional and inside-out contact nucleation by IN is treated with a constant shift of their freezing temperatures. The empirical parameterization is described and compared with available field and laboratory observations and other schemes. Alternative schemes differ by up to five orders of magnitude in their freezing fractions (−30°C). New knowledge from future observational advances may be easily assimilated into the scheme’s framework. The essence of this versatile framework is the use of data concerning atmospheric IN sampled directly from the troposphere.

Synthesis and Photocatalytic Property of BiVO4/FeVO4 Composite Novel Photocatalyst

2010 ◽  
Vol 129-131 ◽  
pp. 784-788 ◽  
Author(s):  
Min Wang ◽  
Qiong Liu ◽  
Dong Zhang
Keyword(s):  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Photocatalytic Property ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Triclinic Phase ◽  
Xrd Patterns

BiVO4/FeVO4 composite photocatalyst samples were prepared by calcining the mixture of FeVO4 and BiVO4 precusor which were prepared through liquid phase precipitation method for further increasing the photocatalytic efficiency of FeVO4. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microsoope（SEM）and specific surface area (BET). The photocatalytic activity was evaluated by photocatalytic degradation of methyl orange (MO) solution under visible light. The XRD patterns indicate that BiVO4/FeVO4 composite photocatalysts consist of triclinic phase and the lattice was not distorted beacause of doping Bi. But the morphology change greatly and the specific surface area has little change. In the experimental conditions used, the optimal photocatalytic activity for all the prepared samples was reached when BiVO4 doping was 22 at%. The degradation rate of MO was increased by 20％ or so than that of pure FeVO4.

Leaf green-white variegation is advantageous under N deprivation in Pelargonium×hortorum

2015 ◽  
Vol 42 (6) ◽  
pp. 543 ◽  
Author(s):  
Cyril Abadie ◽  
Marlène Lamothe ◽  
Caroline Mauve ◽  
Françoise Gilard ◽  
Guillaume Tcherkez
Keyword(s):  
Surface Area ◽  
Photosynthetic Activity ◽  
Leaf Biomass ◽  
Common Occurrence ◽  
Plant Leaves ◽  
Experimental Conditions ◽  
Metabolic Analysis ◽  
Leaf Variegation ◽  
Green Areas ◽  
The Common

Variegation (patchy surface area with different colours) is a common trait of plant leaves. In green-white variegated leaves, two tissues with contrasted primary carbon metabolisms (autotrophic in green and heterotrophic in white tissues) are juxtaposed. It is generally believed that variegation is detrimental to growth due to the lower photosynthetic surface area. However, the common occurrence of leaf variegation in nature raises the question of a possible advantage under certain circumstances. Here, we examined growth and metabolism of variegated Pelargonium × hortorum L.H.Bailey using metabolomics techniques under N deprivation. Our results showed that variegated plants tolerate N deficiency much better, i.e. do not stop leaf biomass production after 9 weeks of N deprivation, even though the growth of green plants is eventually arrested and leaf senescence is triggered. Metabolic analysis indicates that white areas are naturally enriched in arginine, which decreases a lot upon N deprivation, probably to feed green areas. This process may compensate for the lower proteolysis enhancement in green areas and thus contribute to maintaining photosynthetic activity. We conclude that under our experimental conditions, leaf variegation was advantageous under prolonged N deprivation.

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