Search results for "OMAS"

Catalytic Activity of Char Obtained from Fast Pyrolysis in Esterification Reactions

2021

In this study different pathways for obtaining activated carbon with catalytical activity were analysed. Industrially fast pyrolysis is an efficient way of lignocellulosic biomass processing, since in this process various important high value chemicals are obtained. Biochar is obtained as the by-product in fast pyrolysis process from which activated carbon can be acquired with further chemical activation. Different methods for chemical activation of biochar were tested with the obtained activated charcoals being used as a catalyst in esterification reactions to evaluate their potential use as a heterogenic catalyst. Highest catalytical activity was observed when biochar was pre-treated with…

Nitrous oxide emissions in a membrane bioreactor treating saline wastewater contaminated by hydrocarbons

2016

The joint effect of wastewater salinity and hydrocarbons on nitrous oxide emission was investigated. The membrane bioreactor pilot plant was operated with two phases: i. biomass acclimation by increasing salinity from 10 gNaCl L−1 to 20 gNaCl L−1 (Phase I); ii. hydrocarbons dosing at 20 mg L−1 with a constant salt concentration of 20 gNaCl L−1 (Phase II). The Phase I revealed a relationship between nitrous oxide emissions and salinity. During the end of the Phase I, the activity of nitrifiers started to recover, indicating a partial acclimatization. During the Phase II, the hydrocarbon shock induced a temporary inhibition of the biomass with the suppression of nitrous oxide emissions. The r…

Lignin-based activated carbon-supported metal oxide catalysts in lactic acid production from glucose

2021

In this study, heterogeneous biomass-based activated carbon-supported metal oxide catalysts were prepared and tested for lactic acid production from glucose in aqueous solution. Activated carbons were produced from hydrolysis lignin by chemical (ZnCl2) or steam activation and modified with a nitric acid treatment and Sn, Al, and Cr chlorides to obtain carbon-based metal oxide catalysts. The modification of the carbon support by nitric acid treatment together with Sn and Al oxides led to an increase in lactic acid yield. The highest lactic acid yield (42%) was obtained after 20 minutes at 180 °C with the Sn/Al (5/2.5 wt.%) catalyst on steam-activated carbon treated by nitric acid. Reusabilit…

Ionic liquids: a highway with many lanes

Jaundzimušo bērnu aprūpe ar stomu jaundzimušo intensīvās terapijas nodaļā

2017

Bakalaura darba tēma-„Jaundzimušo bērnu aprūpe ar stomu jaundzimušo intensīvās terapijas nodaļā”. Tēmas aktualitāti nosaka - Katru gadu simtiem jaundzimušajiem ir izveidota stoma. Parasti kā rezultātā iedzimta anomālija, traucējumi resnajā zarnā, zarnu nosprostojumi vai ānusa atrēzija. Jaundzimušajiem ar stomu un piemērotu ārstēšanu ir palielinājusies iespēja izdzīvot no 60-80%. Pētījuma mērķis noskaidrot, kāda ir jaundzimušo bērnu aprūpe ar stomu jaundzimušo intensīvās terapijas nodaļā. Pētniecības uzdevumi ir: 1.Apkopot zinātniskajā literatūrā atrodamos pētījumus un statistikas datus par stomu aprūpi jaundzimušajiem; 2.Analizēt D. Oremas teoriju saistībā ar bakalaura darba tēmu 3.Pētījuma…

Return of the Apex Predator : How Brown Trout (Salmo trutta) Re-Establishment Shapes an Ecosystem

2021

Re-establishment of a declined apex predator fish species in a lake ecosystem may have dramatic effects on other fish and plankton community already inhabiting the ecosystem. We studied mechanistically potential impacts of re-establishment of the brown trout (Salmo trutta) in the west-central European Lake Constance focusing on two commercially important fish species: whitefish and Eurasian perch. We compared simulation model outputs from two versions of an allometric trophic network model for Lake Constance, one with and one without the trout as the apex predator. The re-establishment of the declined brown trout reduced the perch population directly by predation and indirectly by increased…

Image analysis with environmental applications

2012

Kaukokartoitusmenetelmiä käytetään tarkkuusmaataloudessa ja metsien inventoinnissa. Pro gradu -tutkielma keskittyy parantamaan analysointiprosessia kasvillisuusmäärien arvioimiseksi esikäsitellyistä ilmakuvista ja digitaalisesta korkeusmallista. Tutkielmassa esitellään evolutiivinen optimointimenetelmä viljapellon biomassojen estimoimiseksi ja tutkitaan biomassaestimaattien tekoa eri menetelmin radiometrisesti korjatuista spektrikaistoista. Tutkielmassa pohditaan myös vaihtoehtoja puulajeittaisten tilavuuksien estimoimiseksi metsistä. Remote sensing methodologies are employed in the fields of precision agriculture and forest industry. This thesis focuses on enhancing analysation process for…

Three zone modeling of downdraft biomass gasification : equilibrium and finite kinetic approach

2013

Mathematical models and simulations are being practiced exceedingly in the field of research and development work. Simulations provide a less expensive means of evaluating the benefits and associated risk with applied field. Gasification is a complex mechanism, which incorporates thermochemical conversion of carbon based feedstock. Therefore, simulation of gasification provides a better comprehension of physical and chemical mechanism inside the gasifier than general conjecture and assist in optimizing the yield. The main objectives of present thesis work involve formulation of separate sub-model for pyrolysis and oxidation zone from published scientific references, and assembling it with p…

Production of ethyl lactate by activated carbon-supported Sn and Zn oxide catalysts utilizing lignocellulosic side streams

2021

In this study, activated carbon-supported Sn and Zn oxide catalysts were prepared from hydrolysis lignin and used for the conversion of model solutions of trioses, hexoses, and lignocellulosic biomass hydrolysates to ethyl lactate. Both catalysts, SnO2@AC and ZnO@AC, were able to produce ethyl lactate in high yields. SnO2@AC was a more active and selective catalyst in triose (dihydroxyacetone) conversion, providing 99% yield to ethyl lactate. ZnO@AC, by contrast, was more selective in glucose and hydrolysate conversion, with a yield of 60% and 85%, respectively. The ethyl lactate yields were significantly higher than those from the optimized model solution experiments when using ZnO@AC cata…

Sustainable Biomass-Derived Carbon Electrodes for Potassium and Aluminum Batteries: Conceptualizing the Key Parameters for Improved Performance

2023

The development of sustainable, safe, low-cost, high energy and density power-density energy storage devices is most needed to electrify our modern needs to reach a carbon-neutral society by ~2050. Batteries are the backbones of future sustainable energy sources for both stationary off-grid and mobile plug-in electric vehicle applications. Biomass-derived carbon materials are extensively researched as efficient and sustainable electrode/anode candidates for lithium/sodium-ion chemistries due to their well-developed tailored textures (closed pores and defects) and large microcrystalline interlayer spacing and therefore opens-up their potential applications in sustainable potassium and alumin…