1,721,004 research outputs found
Characterization of materials used in the manufacture of ceramic tile with incorporation of ornamental rock waste
Full text linkThe production of ceramic tiles, such as tiles, has a great environmental impact, either in
the extraction of natural raw materials or gas emissions in the burning stages. The use of industrial
solid waste in ceramic materials can contribute to the reduction of these impacts, according to the
characteristics of solid waste and its interaction with ceramic materials in the processing steps. Thus,
this study aimed to characterize the materials needed to make a ceramic tile with incorporation of
ornamental rock waste (ORW), thus evaluating its main characteristics regarding the feasibility of this
incorporation. The physical characterization of the clays used in the production of ceramic artifacts
was performed, and for the waste the mineralogical analyzes were performed, through x-ray diffraction
(XRD), microstructure analysis from confocal optical microscopy, after sintering the prototypes and
chemical analysis by X-ray spectroscopy (EDX). Soon after the raw materials went through the step
of conformation and preparation of the prismatic specimens by the process of extrusion of the ceramic
mass, with an incorporation of the ORW in 0% and 15% of the ceramic mass, for its subsequent The
prototypes were sintered at three different temperatures (850 °C, 950 °C and 1,050 °C). The specimens
were submitted to technological tests of mechanical resistance, water absorption, firing shrinkage and
porosity to evaluate the incorporation viability. The results indicated the presence of quartz particles
in all raw materials, and also that the clays of the study region are predominantly kaolinitic. The
presence of these materials in the ceramic masses directly influences the micrographs, because they
result in the formation of liquid phase, inert particles that can turn the site into a stress concentration
point and when incorporated in the ORW the specimens met the technical specifications of the
Brazilian standard for application on ceramic tiles. The results found in the technological tests carried
out, that the incorporation of 15% of ornamental rock waste in both clays did not affect the tile
properties, indicating the feasibility of incorporating this waste in civil construction, minimizing the
impacts generated
Vertical photobioreactor for household Spirulina cultivation
Full text linkMagistritöö
Tootmistehnika õppekavalTöö eesmärgiks on konstrueerida vertikaalne fotobioreaktor koduseks Spirulina
kasvatamiseks.
Töö on jaotatud kuueks peatükiks, kus esimeses peatükis kirjeldatakse mikrovetikaid
ning nende kasutusvaldkondi. Teises peatükis selgitatakse ökotoodete populaarsust ning
Spriulina kasulikkust inimestele. Kolmandas peatükis antakse ülevaade erinevatest
mikrovetikate kasvatusviisidest ja kasvukeskkonda mõjutavatest teguritest. Neljandas
peatükis tuuakse välja kavandatavale seadmele esitatavad nõuded, kirjeldatakse
materjalide valikut, konstrueeritakse vertikaalne väliselt valgustatud torureaktor ning
teostatakse arvutused valguse intensiivsuse modelleerimiseks. Viiendas peatükis
teostatakse katsetööd biomassi kontsentratsiooni leidmiseks ja valguse intensiivsuse
mõõtmised LI-COR LI190/R kvantsensori abil. Kuuendas peatükis tuuakse välja
katsetulemused ning teostatakse tulemuste analüüs.The purpose of this thesis was to construct a vertical photobioreactor for small-scale
Spirulina cultivation.
The thesis is divided into six chapters, where in the first chapter microalgae and the
usage of it is explained. In the second chapter, popularity of eco-products and benefits of
Spirulina is explained. Third chapter gives an overview of different methods used to
cultivate microalgae and explains the conditions needed. In the fourth chapter, the
requirements of photobioreactor and choice of materials are explained, prototype design
is described and calculations for light intensity modelling are made. Experimental work
for finding biomass concentration and measuring light intensity using LI-COR LI190/R
quantum sensor is described in the fifth chapter. In the last chapter test results and
analysis are presented
Degradation of lignocellulosic raw material using explosive decompression
Full text linkTöö eesmärgiks oli uurida lämmastikplahvatuse eeltöötlusmeetodi sobivust
linnahaljastuses tekkivate jäätmete töötlemiseks sihiga toota bioetanooli ning analüüsida
praktilistele katsetustele toetudes hetkel kütustelaboris kasutatava seadmestiku puudusi,
mille põhjal pakkuda välja tehniline lahendus nende puuduste likvideerimiseks ja
eeltöötluse efektiivsemaks muutmiseks. Praktiliste katsetuste eesmärgiks oli määrata
seadmele esitatavad minimaalsed nõudmised temperatuuri ja rõhu suhtes, millele toetuvad
antud töös teostatud arvutused.
Hetkel kasutusel oleval seadmestikul esineb mitmeid puudusi, mille likvideerimine
muudaks protsessi oluliselt efektiivsemaks:
1. Seadmestik töötab tsükliliselt, mis tingib suure ajakulu. Korraga töödeldava
biomassi hulk on väike. 100 g kuiva biomassi töötlemiseks ehk ühe katse
teostamiseks kulunud aeg 125°C-ga oli keskmiselt 2,5 tundi ja 175°C-ga 3,5 tundi.
2. Reaktoris puudub segisti ja küttekeha on otseses kontaktis reaktori seinaga,
mistõttu osa biomassi söestub reaktori seintele.
3. Jääksoojuse kasutamist ei toimu.
Magistritöö tulemusena väljapakutud seadmestiku eelised hetkel kasutusel oleva
seadmestiku ees:
1. Ajakulu vähendamiseks ja seadme tootlikkuse tõstmiseks on uus tehniline lahendus
pidevprotsessiline ja võimaldab töödelda antud juhul 1000L biomassi segu
ööpäevas (100 kg kuiva lignotsellulooset biomassi).
2. Välja pakutud lahendus on varustatud segistiga, mis ei lase biomassil ladestuda
mahuti seintele. Segamisega tagatakse ka parem kontakt süsteemis kasutatava
lämmastikuga. Biomassi soojendamine algab eelsoojendamisega mahutites ja
jätkub spiraalses torureaktoris kuuma õli vahendusel.
3. Välja pakutud lahenduse puhul kasutatakse eeltöötluse läbinud biomassi jahtumisel
eralduvat jääksoojust biomassi eelsoojendamiseks.The aim of this master’s thesis was to analyse the advantages and disadvantages of different
equipment for the pre-treatment of lignocellulosic biomass, used to produce bioethanol, and to
provide a technical solution for a continuous nitrogen explosion pre-treatment apparatus.
Practical experiments were carried out using two different lignocellulosic urban waste:
autumn maple leaves (V. Leht) and a mixture of leaves, grass and twigs (HJ). The aims of
these experiments were to determine the effectiveness of the nitrogen explosion pre-treatment
method and to determine the drawbacks of the apparatus used in fuel laboratory at present.
The objective was to provide a pre-treatment apparatus which would work in continuous
process and would not have the faults that the apparatus currently in use has
Design of the transition system for sequestration of CO2 from flue gas into microalgal biomass in a photobioreactor
Full text linkMagistritöö Tootmistehnika erialalKäesoleva magistritöö eesmärgiks on konstrueerida siirdesüsteem, mis võimaldab siduda korstnagaasis leiduva süsihappegaasi mikrovetika biomassi.
Töös antakse ülevaade biokütuste liikidest, korstnagaasi koostisest ja korstnagaasi mõjudest mikrovetikate kasvule. Käesolevas töös keskendutakse kolmanda põlvkonna biokütuste tootmissüsteemile, mis kasutab korstnagaasis olevat CO2.
Püstitatud eesmärgi saavutamiseks koostati vajalikud mudelid ja tehti arvutused, mille alusel konstrueeriti esmane siirdesüsteem töö autori poolt varasemalt konstrueeritud fotobioreaktorile. Siirdesüsteemi puhul on kriitilise tähtsusega veesamba kõrgus fotobioreaktoris ja põlemise materjal katlas.
Vastava siirdesüsteemi konstrueerimisega saab läbi vaid üks etapp suuremast tööst. Nimelt on edaspidi kavas vastava süsteemi efektiivsuse testimine ja arendamine valitud mikrovetikate kasvatamisel.The aim of the master´s thesis "Design of the transition system for sequestration of CO2 from flue gas into microalgal biomass in a photobioreactor" was to design transition system, which allows sequestration of carbon dioxide from the flue gas into microalgal biomass. In literature review we described biofuel generations, flue gas composition, it´s influence on microalgae growth and suitable microalgae for biofuel production and flue gas sequestration. Present study concentrates on third biofuel generation, which is based on microalgae, suitability to sequestrate carbon dioxide, which is found in flue gas. To accomplish set goal, calculations were done and some models were drawn, on which basis was designed primary transition system for the photobioredactor constructed previously by the same author. The most important fo the trasition system was water column height and material of the fuel in the boiler. Respective design of the transition system is only one phase of the bigger work. Next phase would be to test and develop the given system and the connected photobioreactor
Utilisation of microalgae grown on cattle slurry digestate as a carbon source in biogas production
No full textBakalaureusetöö
Kalanduse ja vesiviljeluse õppekavalNõudlus alternatiivsete kütuste tootmiseks on maailmas üha kasvav, ning sellest tulenevalt on
vaja leida uusi võimalusi biokütuste efektiivsemaks tootmiseks. Maailmas on näiteid, kus on
kasutatud biogaasijaamade efektiivsemaks muutmisel mikrovetikaid, kasutades nende
kasvatamisel toiteallikatena põllumajanduses tekkivaid jääke. Bakalaureusetöö eesmärk on välja
selgitada, kas veiseläga digestaat on sobilik toiteainete allikas erinevatele mikrovetikatele ning
anda hinnang, kas nende kasutamine lisasubstraadina on sobilik olemasolevate biogaasijaamade
efektiivsemaks muutmisel. Töös antakse ülevaade peamistest vetikaliikidest, mida sel eesmärgil
oleks võimalik kasutada. Seejärel selgitatakse, kuidas valiti vetikaliikidest välja sobivaim.
Esitatakse analüüs lahjendatud veiseläga toitel kasvatatud vetikaliigi biomassi juurdekasvu kohta
16 päeva kestnud katse vältel. Tulemustes antakse ülevaade, millist vetikaliiki biogaasijaamade
efektiivsemaks muutmisel oleks sobilik kasutada ning millist mõju avaldavad veiseläga keemilised
omadused vetikatele. Arutelus tuuakse ka välja, millised väljavaated on mikrovetikate
lisasubstraadina kasutamisel biogaasijaamade tootlikkuse parendamiseks.Demand for alternative fuels is growing worldwide, and new opportunities for more efficient
production of biofuels are needed. There are examples in the world where microalgae have been
used to make biogas plants more efficient, using agricultural residues as food sources. The aim
of the bachelor's thesis is to find out whether cattle slurry digestate is a suitable source of
nutrients for various microalgae and to assess whether their use as an additional substrate is
suitable for making existing biogas plants more efficient. The paper provides an overview of the
main algal species that could be used for this purpose, then explains how the most suitable algal
species was selected, and provides an analysis of the increase in its biomass, fed with diluted
cattle slurry over 16 days. The results provide an overview of which type of algae would be
suitable for making biogas plants more efficient and what effect the chemical properties of cattle
slurry have on algae. The discussion also highlights the prospects for using microalgae as an
additional substrate to improve the productivity of biogas plants
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effect of radiofrequency electromagnetic field to the production of Arthrospira (Spirulina) platensis
Full text linkBakalaureusetöö
Vee ja maismaa ökosüsteemide rakendusbioloogia õppekavalArthrospira perekonna liikide kasvatamise tööstuslik potensiaal on laialdaselt tuntud. A.
platensist saab kasutada toiduks või toota sellest valke, beetakaroteeni, vitamiine,
fükotsüaniini ja gamma-linoleenhapet. (Vonshak, 1997)
Käesoleva töö raames kasvatati tsüanobakterit Arthrospira platensis laboritingimustes ja
uuriti ruuteri raadiosagedusliku elektromagnetkiirguse (EMK) mõju sellele. Peamiseks
eesmärgiks oli analüüsida, kas raadiosagedusliku EMK eest Faraday puuriga varjestatud
tsüanobakterite biomassi juurdekasv erineb varjestamata katsegrupi omast. Varasemalt on
uuritud püsiva magnetvälja mõju A. platensisele, kuid mitte ruuteri toimet, mille EMK on
nõrgem ja pulseeriv.
Katseseadmetena kasutati bioreaktoreid, mis paiknesid luminofoorlambi all ja olid
ühendatud suruõhuga, mis aitas segada mikrovetikalahust ja tagas pideva CO2 juurdevoolu.
Kaks bioreaktorit (kontrollgrupp) olid varjestatud maandatud metallvõrgu abil ja kolm
bioreaktorit varjestamata (katsegrupp). Andmete analüüs näitas, et ruuteri EMK ei mõjutanud katsegrupi produktsiooni, sest
varjestamata katsegrupi keskmine juurdekasv ei erinenud statistiliselt varjestatud
kontrollgrupi keskmisest juurdekasvust (p-väärtus on 0,26; seega suurem kui 0,05).
Autori arvates võiks tulevikus sarnase ülesehitusega katse korral teha rohkem
katseseeriaid. Lisaks võiks uurida mobiiltelefonide EMK mõju mikrovetikatele ning
koguda andmeid paljude erinevate näitajate kohta, mitte piirduda vaid biomassi
produktsiooniga. Samuti võiks sarnaseid katseid teostada teiste mikrovetikatega, mille
kasvatamisel on tööstuslikku potensiaali.The industrial potential of the Arthrospira family is widely known. A. platensis can be used
for food or to produce proteins, beta-carotene, vitamins, phycocyanin and gamma-linolenic
acid. (Vonshak, 1997)
In the framework of this work, cyanobacteria Arthrospira platensis was grown in
laboratory conditions and the effect of radiofrequency electomagnetic radiation (EMR) of
a router was examined. The main aim was to analyse, whether or not the increase of the
cyanobacteria biomass was different in the control group, shielded by the Faraday cage,
from the test group that was exposed to radio frequency EMR. In earlier research, the effect
of a static magnetic field to A. platensis has been examined, but not the effect of a router,
that has a weaker and pulsating EMR.
Bioreactors were used as test equipment. The biorectors were located under a fluorescent
lamp and connected to pressurised air, which helped to mix the microalgae solution and
provided the CO2 necessary for their growth. Two bioreactors (control group) were
shielded by grounded metal wire mesh and three bioreactors were left unshielded (test
group). Analysis of data revealed, that router’s EMR had no effect on the test group’s production,
because the average increase of the non-shielded test group was statistically not different
from shielded control group's average increase (p-value is 0,26; therefore greater than
0,05).
In the opinion of the author, in the future more series of experiments should be conducted.
Also, the effect of cellphone EMR to microalgae could be studied and data could be
collected of a wide range of indicators, not only about the biomass production. Similar tests
could also be carried out with other microalgae, that have industrial potential
Design of the support frame for photobioreactor
Full text linkKäesoleva bakalaureuse töö eesmärk oli projekteerida ja praktiliselt valmis teha fotobioreaktori
tugiraam ja anda sellele hinnang. Hinnati autori ja töö läbiviija praktilisi oskusi ning oskust
SolidWorks keskkonnas metallist struktuure analüüsida.
Eesmärkide täitmiseks teostati autori ja juhendaja visiooni järgi SolidWorks virtuaalses
keskkonnas tugiraami mudel ning kui see vastas soovidele, siis alustati materjalide valikust.
Kõigepealt prooviti kahte erinevat materjali – teras ja alumiinium, virtuaalselt vastupidavus
testi jaoks. Testist selgus, et antud lõputöö tugiraam kanntab kuni 450 kg raskust, mis on
rohkem, kui ettenähtud ( 360 kg). Kui test edukalt läbitud ning muudatused raami ehituses
sisseviidud, sai tellitud materjal, milleks sai A36 terasest nelikanttoru ehk ruutristlõikega
terastoru.
Raami valmides SolidWorksis sai projekteeritud PVC torude polümeerist toed, mis toetusid
raami vahele. Seejärel alustati 6 m nelikanttorude lõikamist lintsaega, mis oli väga
aeganõudev protsess, sest ettenihe oli väike ning ei tahetud lõikehambaid nürida. Materjali
valmimisel alustati täisnurksete klambrite abil torude omavahelist täisnurkset ühendamist ning
seejärel keevitamist. Keevitati alguses paari punkti, ehk väikse punktliitega, et raam koos
püsiks, seejärel eemaldati klambrid ning keevitati lõplikult torud omavahel kokku. Kõik
sektsioonid valmistati eraldi ning hiljem, kui nurkade nurkrauad olid samuti külge keevitatud,
tõsteti üksteise peale ning puuriti sektsioonide liitkõrvadest ja raami jalgadest augud läbi.
Saavutati tugev tugiraam, mis täidab ettenähtud kriteeriumid.The objective of this Bachelor’s thesis was to design the most suitable support frame for the
photobioreactor constructed in the Biofuels lab of Institute of Technology. The thesis assesses
the material selection, the tools used and the design of the framework in CAD environment
and aims at generating the most practical frame for the motorized mixing photobioreactor.
To achieve this objective, different metal processing work methods were applied and their
advantages and disadvantages were described. The support frame was modelled in
SolidWorks and different metals were tested to determine the most suitable material. Steel
square tubing was found the most useful and practical to suit the photobioreactors support
frame. Stress tests in SolidWorks were done to achieve the goal of the frame supporting at
least 360 kg of biomass and PVC tubing. The tests were done on the lower part of the frame.
The results of this design and work showed that it is not easy to create a simple support frame
when the element that needs support has wide variety of functional requirements. The frame
was also done in real life and different tools were used to create it. Welding, cutting and
fitment issues went hand in hand in this project
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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