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812. Drag reduction of dense fine-grained slurries
- Creator:
- Vlasák, Pavel, Chára, Zdeněk, and Štern, Petr
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- kaolin slurry, drag reduction, experimental investigation, peptization, slurry rheology, kaolinové suspenze, snižování tření, experimentální výzkum, peptizace, and reologie suspenzí
- Language:
- Slovak
- Description:
- Attractive and repulsive forces acting in the slurry due to different ions absorbed on surface of fine particles, especially colloidal ones, strongly affect the flow behaviour of highly concentrated fine-grained slurries. The attractive forces between the fine-grained solid particles initiate the coagulation process, which gives rise to voluminous aggregates where a large amount of water is fixed. A modification of the physicalchemical environment of the slurry by addition of a peptizing agent produces repulsive forces between particles. They result in destruction of the aggregates, water originally fixed in the aggregates is liberated, the viscous friction can play a larger role in the slurry, which is liquefied. To prove these process three different kaolin-water mixtures were tested with an overpressure capillary viscometer, rotational viscometer, and experimental pipeline loop. The effect of two peptizing agents and their concentration was investigated. It was demonstrated that even very low concentration of peptizing agent results in a significant reduction in the apparent viscosity and in the yield stress. and Přitažlivé a odpudivé síly působící mezi částicemi v suspenzi v důsledku různých iontů absorbovaných povrchem jemných, zejména koloidních částic, silně ovlivňují tokové chování vysoce koncentrovaných jemnozrnných suspenzí. Přitažlivé síly mezi jemnými částicemi iniciují proces koagulace, umožňují vznik objemných agregátů, v nichž je vázáno značné množství vody. Změna fyzikálně-chemického prostředí suspenze přidáním peptizačního činidla podpoří vznik odpudivých sil mezi částicemi, které způsobí rozbití objemných agregátů a voda vázaná v agregátech se uvolní, vazké tření tak bude hrát v suspenzi významnější roli a dojde k ztekucení suspenze. Tento proces byl ověřen experimentálním výzkumem třech různých kaolinových suspenzí jednak na kapilárním přetlakovém viskozimetru, na rotačním viskozimetru a na experimentální potrubní trase. Byl ověřen účinek dvou peptizačních činidel a bylo ukázáno, že velmi nízká koncentrace peptizačního činidla vede k významné redukci zdánlivé viskozity a počátečního napětí.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
813. DRESS syndróm – kazuistika
- Creator:
- Adamcová, Monika, Koller, Tomáš, and Payer, Juraj
- Format:
- print, text, and regular print
- Type:
- model:article, article, Text, abstrakt z konference, and TEXT
- Language:
- Czech and Slovak
- Description:
- M. Adamcová, T. Koller, J. Payer
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
814. Drevené sudy a ich využitie pri skladovaní nápojov a potravín (stredoveké Uhorsko) /
- Creator:
- Nemeš, Jaroslav,
- Type:
- text and studie
- Subject:
- Dějiny středověku a novověku (obecně), sudy, řemeslo, bednářství, kultura hmotná, skladování potravin, potraviny, prameny písemné, Maďarsko, světové dějiny středověku (do r. 1492), světové dějiny 1492-1648, hmotná kultura, umělecká řemesla, and oděv, strava
- Language:
- Slovak
- Description:
- Holzfässer und ihre Nutzung bei der Lagerung von Getränken und Lebensmittel (im mittelalterlichen Ungarn).
- Rights:
- unknown
815. Droplet infiltration dynamics and soil wettability related to soil organic matter of soil aggregate coatings and interiors
- Creator:
- Fér, Miroslav, Leue, Martin, Kodešová, Radka, Gerke, Horst H., and Ellerbrock, Ruth H.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- aggregates, clay and organic matter coatings, WDPT, contact angle, and DRIFT spectroscopy
- Language:
- Slovak
- Description:
- The organo-mineral coatings of soil aggregates, cracks, and biopores control sorption and macropore-matrix exchange during preferential flow, in particular in the clay-illuvial Bt-horizon of Luvisols. The soil organic matter (SOM) composition has been hypothesized to explain temporal changes in the hydraulic properties of aggregate surfaces. The objective of this research was to find relations between the temporal change in wettability, in terms of droplet infiltration dynamics, and the SOM composition of coated and uncoated aggregate surfaces. We used 20 to 40 mm sized soil aggregates from the Bt2 horizon of a Haplic Luvisol from loess that were (i) coated, (ii) not coated (both intact), and (iii) aggregates from which coatings were removed (cut). The SOM composition of the aggregate surfaces was characterized by infrared spectroscopy in the diffuse reflection mode (DRIFT). A potential wettability index (PWI) was calculated from the ratio of hydrophobic and hydrophilic functional groups in SOM. The water drop penetration times (WDPT) and contact angles (CA) during droplet infiltration experiments were determined on dry and moist aggregate samples of the three types. The decrease in the CA with time was described using the power function (CA(t) = at–b). For dry aggregates, the WDPT values were larger for coated as compared to uncoated regions on the aggregate surfaces, and increased with increasing PWI value (R2 = 0.75). The a parameter was significantly related to the WDPT (R2 = 0.84) and to the PWI (R2 = 0.64). The relations between the b parameter and the WDPT (R2 = 0.61) and the PWI (R2 = 0.53) were also significant. The WDPT values of wet soil aggregates were higher than those of dry aggregates due to high water contents, which limited the droplet infiltration potential. At the wet aggregate surfaces, the WDPT values increased with the PWI of the SOM (R2 = 0.64). In contrast to dry samples, no significant relationships were found between parameters a or b of CA(t) and WDPT or PWI for wet aggregate surfaces. The results suggest that the effect of the SOM composition of coatings on surface wettability decreases with increasing soil moisture. In addition to the dominant impact of SOM, the wettability of aggregate surfaces could be affected by different mineralogical compositions of clay in coatings and interiors of aggregates. Particularly, wettability of coatings could be decreased by illite which was the dominant clay type in coatings. However, the influence of different clay mineral fractions on surface wettability was not due to small number of measurements (2 and 1 samples from coatings and interiors, respectively) quantified.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
816. Drought impact on ground beetle assemblages (Coleoptera, Carabidae) in Norway spruce forests with different management after windstorm damage – a case study from Tatra Mts. (Slovakia)
- Creator:
- Šustek, Zbyšek, Vido, Jaroslav, Škvareninová, Jana, Škvarenina, Jaroslav, and Šurda, Peter
- Type:
- article, model:article, and TEXT
- Subject:
- drought, ground beetle, windstorm, forest management, and Norway spruce
- Language:
- Slovak
- Description:
- After the windstorm of November 2004, the ground beetle assemblages (Coleoptera, Carabidae) differentiated after the windstorm into four groups reflecting degree of damaging and forestry management (intact stand, fallen timber in situ, extracted timber, fire). The stand with fallen timber reduced abundances of original species. Removal of timber eliminated sensitive forest species and favored tolerant species, whereas the fire allowed invasions of field species. Later, the assemblages on burned sites converged to those in the unburned sites. Their restoration has a sigmoid-like course. Independently on the above differentiation and course assemblage succession, episodes of severe drought resulted with a 1–2-years delay in sudden decline of number of individuals and species. Their numbers were restoring after longer humid periods. Because these extremes occur with a considerable regularity, the observed extremes of fluctuations of number of species and individuals represent the variability limits of the Carabid assemblages in such conditions. The Standardized Precipitation Evapotranspiration Index was shown, using the cross-correlation of SPEI and number of individuals and species of Carabids, as a suitable means to explain and predict such changes for the period of 1–2 years.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
817. Druhý vatikánsky koncil: Obroda cirkvi a zjednotenie kresťanov /
- Creator:
- Šrobár, Štefan,
- Type:
- text and články
- Subject:
- Dějiny křesťanské církve, koncil druhý vatikánský (1962-1965), církev římskokatolická, světové dějiny od r. 1945 do současnosti, and církevní právo, inkvizice
- Language:
- Slovak
- Rights:
- unknown
818. Držanie diét u adolescentov
- Creator:
- Miertová, Michaela
- Format:
- 460-467, braille, electronic resource, remote, and elektronický zdroj
- Type:
- model:article, article, Text, statistics, and TEXT
- Subject:
- lidé, mužské pohlaví, ženské pohlaví, redukční dieta--psychologie--statistika a číselné údaje, tělesná hmotnost, mladiství, mladý dospělý, průzkumy a dotazníky, interpretace statistických dat, statistika jako téma, index tělesné hmotnosti, and krása
- Language:
- Czech, Slovak, and English
- Description:
- Cieľ: Výskum bol zameraný na identifikáciu drţania diéty u adolescentných respondentov a niektorých príčin jej drţania vo vzťahu k pohlaviu a veku. Metodika: Na získanie empirických dát boli pouţité vybrané poloţky sebaposudzovacieho meracieho nástroja s názvom Mapovanie stravovacích návykov medzi adolescentmi (The Project EAT Survey, Neumark- Sztainer et al.). Výskumnú vzorku tvorilo 387 adolescentných respondentov, toho času študentov prvých a štvrtých ročníkov stredných škôl. Výsledky: Podľa výsledkov výskumu ţeny častejšie drţia diéty (redukčné alebo pre jej udrţanie) či uţ v minulom roku (p = 0,002) aj v terajšej dobe (p = 0,000). Sú nespokojné so svojou hmotnosťou (p = 0,000) a postavou (p = 0,009). Respondenti vo veku 18 - 20 rokov uviedli, ţe si ich členovia rodiny doberali alebo si robili posmech z ich hmotnosti (p = 0,000). Vyššie percento ţien zaţilo negatívne hodnotenie ich hmotnosti zo strany členov rodiny (27,5 %) a vrstovníkov (33,5 %). Záver: Sestra v klinickej praxi môţe byť nápomocná pri identifikovaní drţania diét u adolescentov a jej príčin z hľadiska prevencie dopadu drţania diét na telesné a duševné zdravie adolescenta a pri realizácii uţ cielených intervencií, napr. edukácie v rámci takto obsahovo zameranej prevencie., Aim: The research was aimed at identifying dieting among adolescent respondents and some of the reasons for its keeping in relation to sex and age. Methods: For obtaining empirical data selected items of self-assessing measuring tool called Mapping dietary habits among adolescents were used (The Project EAT Survey, Neumark-Sztainer et al.). The research sample consisted of 387 adolescent respondents, previously high school students (of the first and fourth study year). Results: According to results of research women more frequently keep a diet (in order to lose weight or keep it the same) in last year (p = 0,002) as well as at present-day period (p = 0,000). They are not satisfied with their weight (p = 0,000) and figure (p = 0,009). Respondents aged 18-20 years reported that their family members have teased or made fun of their weight (p = 0,000). A higher percentage of women had experience a negative evaluation of their weight on the part of the family members (27,5 %) and peers (33,5 %). Conclusion: A nurse in clinical practice can be helpful in identifying dieting among adolescents and its causes in order to prevent the impact of diets on physical and mental health of adolescent and in the implementation of already targeted interventions, e.g. education in the context of the following content targeting prevention., Michaela Miertová, and Literatura 40
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
819. Dům na Žižkově náměstí v Českých Budějovicích /
- Creator:
- Naňková, Věra,
- Type:
- text and články
- Subject:
- Architektura, Bayer, Pavel Ignác,, domy, fasády, architekti, české země 1620-1740, města, obce, and architektura, architekti
- Language:
- Slovak
- Rights:
- unknown
820. Dunajská Streda
- Publisher:
- Vojenský zeměpisný ústav
- Format:
- map and 1 mapa : barevná ; 39 x 52 cm na listu 48 x 62 cm
- Type:
- model:map, cartographic, and IMAGE
- Subject:
- udc:913(4), Konspekt:7, udc:912, udc:913(437.6), udc:912.43, udc:(084.3), Konspekt:Geografie Evropy, reálie, cestování, Konspekt:Mapy. Atlasy. Glóby, and czenas:Dunajská Streda (Slovensko : oblast)
- Language:
- Czech, Slovak, and Hungarian
- Description:
- 4859, Legenda, Edice dle kladu listů, and (Language) Místní názvy slovensky a maďarsky
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public