Search results for " Osmo"
showing 10 items of 79 documents
ALTERAZIONI DEL METABOLISMO DEL SODIO NELL’ANZIANO: CASISTICA DI UN REPARTO DI GERIATRIA PER ACUTI
2014
Premessa. Le alterazioni della concentrazione plasmatica del sodio rappresentano gli squilibri elettrolitici più frequenti nei pazienti ospedalizzati e l’incidenza e la prevalenza aumentano con l’età. L’invecchiamento rappresenta un fattore di rischio indipendente e molto significativo per le alterazioni del bilancio del sodio e dell’acqua. Numerosi sono i fattori che cooperano nell’aumentare la suscettibilità dell’anziano a tali squilibri, dipendendo da modificazioni fisiologiche età correlate dei meccanismi che regolano il bilancio idro-salino dell’organismo, dalla progressiva riduzione delle capacità di compenso che caratterizza il fenomeno stesso dell’invecchiamento e dalle comorbilità,…
Marrëdhëniet e Patriarkanës së Ohrit me Sicilinë dhe komunitetet arbëreshe (shek. XVI-XVIII)
2018
Indagine storiografica sui rapporti tra il Patriarcato di Ocrida e la Sicilia. Presenze di ecclesiastici ortodossi nelle comunità albanesi di Sicilia (sec. XVI-XVIII)
Effect of drought on sorbitol and sucrose metabolism in sinks and sources of peach
2000
In peach (Prunus persica [L.] Batsch.), sorbitol and sucrose are the two main forms of photosynthetic and translocated carbon and may have different functions depending on the organ of utilization and its developmental stage. The role and interaction of sorbitol and sucrose metabolism was studied in mature leaves (source) and shoot tips (sinks) of'Nemaguard' peach under drought stress. Plants were irrigated daily at rates of 100, 67, and 33% of evapotranspiration (ET). The relative elongation rate (RER) of growing shoots was measured daily. In mature leaves, water potential (ψ w ), osmotic potential (ψ s ), sorbitol-6-phosphate dehydrogenase (S6PDH, EC 1.1.1.200), and sucrose-phosphate synt…
Coupling sustainable energy with membrane distillation processes for seawater desalination
2010
Desalination technologies nowadays is a very interesting and emerging alternative to conventional water sources; their high energy consumption, however, generates some problems in adopting them, especially in remote areas where electric grid is not available and fuel transportation is not always sustainable. In this paper a short overview of possible couplings between the membrane distillation technology for desalination and the use of sustainable thermal energy sources is presented. Two case studies of ongoing research projects at Universita di Palermo are also presented.
Regeneration units for thermolytic salts applications in water & power production: State of the art, experimental and modelling assessment
2021
Abstract Thermolytic solutions are often proposed as high salinity or “draw” stream to generate a chemical potential driving force in Salinity Gradient Power (SGP) and Forward Osmosis (FO) technologies. Depleted “draw” solutions exiting the process can be regenerated by a thermal process powered at very-low grade heat, which is able to decompose the salt into gaseous ammonia and carbon dioxide, which can be stripped and then reabsorbed in the draw solution, restoring its initial concentration. In this work, two different experimental prototypes for the regeneration of ammonium bicarbonate aqueous solution were designed, built and tested. The effect of several operating parameters on the reg…
Membrane distillation heat transfer enhancement by CFD analysis of internal module geometry
2011
Module geometry optimisation can be a crucial matter in all separation processes using selective or hydrophobic membranes, e.g. reverse osmosis (RO) and membrane distillation (MD). In fact the choice of suitable channel shape and size can dramatically affect the performance of the process. With reference to the membrane distillation process, temperature polarization phenomena and pres¬sure drops along the channels largely affect the process efficiency (i.e. the efficient use of temperature driving force for the passage of vapour through the membrane) as well as pressure distribution, module mechanical resistance and pumping costs. Several works have been presented so far in literature on th…
Vides faktoru ietekme uz asaru osmolaritāti
2018
Maģistra darbs ir uzrakstīts latviešu valodā, datorsalikumā uz 55 lapām. Tas satur 3 tabulas, 40 attēlus un 40 atsauces uz literatūras avotiem. Darba mērķis bija novērtēt vides faktoru ietekmi uz asaru osmolaritāti un acs priekšējo struktūru izmeklējumu rezultātiem, kā arī noskaidrot šo parametru savstarpējo mijiedarbību. Pētījums norisinājās 3 daļās, 1. daļā “Aptaujas daļā” piedalījās 125 dalībnieki, 2. daļā “Izmeklējumu daļā” piedalījās 54 dalībnieki un 3. daļa “Atkārtoto mērījumu daļā” piedalījās 21 dalībnieks. Rezultāti parādīja, ka gaisa relatīvais mitrums atstāj ietekmi uz asaru osmolaritāti. Asaru osmolaritāte korelē ar Širmera testa rezultātiem, radzenes krāsošanos un TBUT laiku. Ti…
Reservoir characteristics of Mainz pouch studied in animal model
1993
In a canine model of the Mainz pouch, intracavitary pressure and compliance were measured during instillation of isosmotic and hyperosmotic (900 mmol/kg water) solutions of saline. Wall properties of small- and large-bowel segments of the pouch were assessed individually by sonomicrometry. Intraluminal pressures increased more steeply during filling with hyperosmotic solution, resulting in reduced distensibility of small- and large-bowel segments. Additionally, instillation of the hyperosmotic solution resulted in increased amplitudes and frequency of intracavitary pressure waves. The results indicate that this was the result of a combination of intensified bowel contractions and an increas…
Salt extraction regeneration technologies
2022
Abstract A salinity gradient power heat engine is a novel sustainable technology for the conversion of low-grade waste heat (T This chapter presents an overview of the main regeneration technologies based on the “salt extraction strategy” reported in the literature. A salt extraction regeneration unit takes advantage of the property of specific chemical compounds to shift from a soluble form to separable species in solution allowing the salt transfer between the exhausted solutions and aiding their regeneration. The regeneration processes reported here are classified into (i) switchable solubility salts and (ii) thermolytic salts. The first class includes compounds characterized by thermal…
Composite membranes of aromatic-polyamide for desalination: Membrane preparation and characterization.
1987
A new reverse osmosis composite membrane composed of the following aromatic polymer was estudied. Composite membranes were successfully prepared from PTDS by the conventional phase-inversion method. A typical example of the basic membrane performances is as follows; water flux, 440 1/m2 day and salt rejection, 97.7% determined under the pressure of 40 atm., using 0.1% NaCl solution at 25 °C. The PTDS membrane was characterized by its excellent chemical and thermal resistances, especially against acid, alkali and oxidative atmospheres. These features suggest that the PTDS membrane is a promising candidate for water desalination.