Search results for "dab"
showing 10 items of 1280 documents
Thermomechanical degradation of PLA-based nanobiocomposite
2016
Nanobiocomposites are a new class of biodegradable polymer materials with nanometric dispersion of inert particles in a biodegradable polymer matrix that show very interesting properties often very different from those of conventional- filled polymers and also biodegradability. An important issue in the applications of the biodegradable polymers is their easy degradability during processing due to the thermomechanical stress or to the presence of humidity. In this work, the thermomechanical degradation behavior of a nanobiocomposite made by a PLA-based blend and an organomodified montmorillonite has been investigated. The degradation kinetics has been followed by means of rheological, mecha…
Caratterizzazione reologica di sistemi biodegradabili nanocompositi
2012
Desarrollo y caracterización de nuevos nanobiocomposites con propiedades mejoradas mediante varios métodos de procesado de interés en envasado de ali…
2015
El presente trabajo tiene como objetivo mejorar las propiedades de matrices biopoliméricas para su uso en aplicaciones de envasado de alimentos mediante el desarrollo de nanobiocompuestos utilizando diferentes metodologías de procesado o estrategias de incorporación de materiales nanoestructurados en el interior de las matrices biopoliméricas. Dos estrategias de incorporación fueron empleadas. La primera de ellas estaba basada en una pre-incorporación de los aditivos nanoestructurados, también llamados nanoaditivos, en oligómeros de ácido láctico mediante tecnologías de polimerización in situ (específicamente policondensación), dando lugar a masterbatches que, posteriormente, se mezclaban c…
Sākumskolas skolēnu dabaszinātņu sasniegumus ietekmējošie valsts līmeņa faktori starptautiskajos salīdzinošajos pētījumos izglītības vadības skatījumā
2013
Elektroniskā versija nesatur pielikumus
Kvazistatisku atmosfēras piesārņojuma līmeņu kompleksā analīze un modelēšana
2007
Promocijas darbā ir analizēti atmosfēras piesārņojuma līmeņi Rīgā, novērtējot atsevišķu un kompleksu meteoroloģisko parametru ietekmi. Darbā apkopota un kompleksi analizēta atmosfēras piesārņojuma līmeņa veidošanās rosinošo faktoru nozīme; veikta faktoru analīze Rīgas pilsētai ar tālāku mērķi rezultātus izmantot prognostiska modeļa izstrādē; prognostiskie modeļi tiek pārbaudīti eksperimentāli, izstrādājot īstermiņa un ilgtermiņa atmosfēras piesārņojuma līmeņa prognozes atbilstoši meteoroloģisko apstākļu prognozēm un piesārņojuma uzkrāšanās procesiem. Šāda analīze sniedz priekšstatu par būtisko – galvenajiem atmosfēras piesārņojuma līmeņa ietekmes faktoriem, cēloņiem un kritērijiem, tādējādi…
Visitor Regulations vs Rules for visiting Morizsala
1913
Regulations issued by the Riga Society of Naturalists (Naturforscher-Verein zu Rīga; 1845 – 1939) for visitors to Moricsala. The rules were created by approving the first nature protected area in Latvia. The material is stored in the Botany and Mycology collections of the Museum of the University of Latvia.
Rīgas Dabaspētnieku biedrības 50 gadu jubilejas piemiņas ēdienkarte
2020
In 1895, the oldest Latvian Society of Naturalists, the Riga Society of Naturalists (1845 – 1939), celebrated its 50th anniversary. The celebrations also included a social event with a feast, in memory of which a humorous menu based on geological eras was issued. The article provides an insight into both the menu and the society's anniversary celebrations.
Bacon und die Naturphilosophie
1927
On Finite Satisfiability of Two-Variable First-Order Logic with Equivalence Relations
2009
We show that every finitely satisfiable two-variable first-order formula with two equivalence relations has a model of size at most triply exponential with respect to its length. Thus the finite satisfiability problem for two-variable logic over the class of structures with two equivalence relations is decidable in nondeterministic triply exponential time. We also show that replacing one of the equivalence relations in the considered class of structures by a relation which is only required to be transitive leads to undecidability. This sharpens the earlier result that two-variable logic is undecidable over the class of structures with two transitive relations.