Effects of fertilisation and irrigation practices on yield, maturity and storability of onions

Selostus: Lannoituksen ja kastelun vaikutus sipulin satoon, sadon valmistumiseen ja varastokestävyyteen

Response of P, K, Mg and NO‚́ƒ-N contents of carrots to irrigation, soil compaction, and nitrogen fertilisation

Selostus: Maan tiiviyden, sadetuksen ja typpilannoituksen vaikutus porkkanan kivennäisainepitoisuuteen ja ravinteiden ottoon sekä nitraatin kertymiseen

Efficiency of split nitrogen fertilization with adjusted irrigation on potato

Selostus: Jaetun typpilannoituksen käyttömahdollisuudet perunalle

Puhdistetun jäteveden patogeenit ja desinfiointitarve

Turun seudulla kuuden kunnan jätevesien käsittely keskitetään Kakolanmäen kallion sisälle rakennettuun jätevedenpuhdistamoon, joka otetaan käyttöön vuoden 2008 lopulla. Kakolanmäen jätevedenpuhdistamolla on varauduttu tulevaisuudessa kiristyviin lupaehtoihin sekä mahdollisiin puhdistetun jäteveden hygieenistä laatua koskeviin lisämääräyksiin jättämällä tilavaraus puhdistetun jäteveden desinfioimiselle ultraviolettivalolla. Diplomityössä on selvitetty vuoden kestäneessä tutkimusjaksossa 1.9.2006- 31.8.2007 Turun kaupungin keskuspuhdistamolta mereen johdetun puhdistetun jäteveden ja esiselkeytetyn ohitusveden hygieenisen laadun vaihtelua. Jäteveden desinfiointitarvetta on arvioitu tarkastelemalla jätevedenpuhdistamon hygieenistä puhdistustulosta ja jätevesien vaikutusta purkuvesistön hygieeniseen tilaan. Tutkimuksen perusteella virtaama ei vaikuttanut merkittävästi jäteveden ulosteperäisten bakteerien määriin. Sen sijaan jäteveden bakteeripitoisuudet laskivat alhaisissa lämpötiloissa. Lämpötilan vaikutus näkyi selkeämmin esiselkeytetyssä kuin puhdistetussa jätevedessä eli bakteerien poistumiseen aktiivilietevaiheen aikana vaikuttavat muut tekijät. Mitä tehokkaammin aktiivilietevaihe toimi, sitä tehokkaammin myös bakteereja poistui. Taudinaiheuttajabakteerit selvisivät puhdistusprosessista paremmin viileän kauden aikana. Puhdistetun jäteveden hygieeninen laatu ei täyttänyt uimaveden tai kasteluveden laatuvaatimuksia, joten desinfiointitarve olisi perustelua. Jätevesien vaikutus Turun edustan merialueen hygieeniseen tilaan näkyi ajoittain korkeina bakteeripitoisuuksina purkupaikan lähistöllä. Vielä ei ole suoraa näyttöä siitä aiheuttavatko jätevedet purkupaikan lähistön uimarannoilla terveydellisiä riskejä. Jäteveden UV-desinfiointi kannattava toteuttaa vain jos hygieeninen puhdistusvelvoite määrätään. UV-desinfioinnin mitoituksessa Kakolanmäen jätevedenpuhdistamolla tulee ottaa huomioon suurin sallittu hydraulinen painehäviö. Mitoitus voidaan tehdä puhdistamon käyttöönoton jälkeen kun tarvitut prosessimittaustiedot ovat saatavilla.

New families of highly efficient, halogen-free flame retardants for polypropylene (PP)

The driving forces for current research of flame retardants are increased fire safety in combination with flame retardant formulations that fulfill the criteria of sustainable production and products. In recent years, important questions about the environmental safety of antimony, and in particular, brominated flame retardants have been raised. As a consequence of this, the current doctoral thesis work describes efforts to develop new halogen-free flame retardants that are based on various radical generators and phosphorous compounds. The investigation was first focused on compounds that are capable of generating alkyl radicals in order to study their role on flame retardancy of polypropylene. The family of azoalkanes was selected as the cleanest and most convenient source of free alkyl radicals. Therefore, a number of symmetrical and unsymmetrical azoalkanes of the general formula R-N=N-R’ were prepared. The experimental results show that in the series of different sized azocycloalkanes the flame retardant efficacy decreased in the following order: R = R´= cyclohexyl > cyclopentyl > cyclobutyl > cyclooctanyl > cyclododecanyl. However, in the series of aliphatic azoalkanes compounds, the efficacy decreased as followed: R = R´= n-alkyl > tert-butyl > tert-octyl. The most striking difference in flame retardant efficacy was observed in thick polypropylene plaques of 1 mm, e.g. azocyclohexane (AZO) had a much better flame retardant performance than did the commercial reference FR (Flamestab® NOR116) in thick PP sections. In addition, some of the prepared azoalkane flame retardants e.g. 4’4- bis(cyclohexylazocyclohexyl) methane (BISAZO) exhibited non-burning dripping behavior. Extrusion coating experiments of flame retarded low density polyethylene (LDPE) onto a standard machine finished Kraft paper were carried out in order to investigate the potential of azoalkanes in multilayer facings. The results show that azocyclohexane (AZO) and 4’4-bis (cyclohexylazocyclohexyl) methane (BISAZO) can significantly improve the flame retardant properties of low density polyethylene coated paper already at 0.5 wt.% loadings, provided that the maximum extrusion temperature of 260 oC is not exceeded and coating weight is kept low at 13 g/m2. In addition, various triazene-based flame retardants (RN1=N2-N3R’R’’) were prepared. For example, polypropylene samples containing a very low concentration of only 0.5 wt.% of bis- 4’4’-(3’3’-dimethyltriazene) diphenyl ether and other triazenes passed the DIN 4102-1 test with B2 classification. It is noteworthy that no burning dripping could be detected and the average burning times were very short with exceptionally low weight losses. Therefore, triazene compounds constitute a new and interesting family of radical generators for flame retarding of polymeric materials. The high flame retardant potential of triazenes can be attributed to their ability to generate various types of radicals during their thermal decomposition. According to thermogravimetric analysis/Fourier transform infrared spectroscopy/MS analysis, triazene units are homolytically cleaved into various aminyl, resonance-stabilized aryl radicals, and different CH fragments with simultaneous evolution of elemental nitrogen. Furthermore, the potential of thirteen aliphatic, aromatic, thiuram and heterocyclic substituted organic disulfide derivatives of the general formula R-S-S-R’ as a new group of halogen-free flame retardants for polypropylene films have been investigated. According to the DIN 4102- 1 standard ignitibility test, for the first time it has been demonstrated that many of the disulfides alone can effectively provide flame retardancy and self-extinguishing properties to polypropylene films at already very low concentrations of 0.5 wt.%. For the disulfide family, the highest FR activity was recorded for 5’5’-dithiobis (2-nitrobenzoic acid). Very low values for burning length (53 mm) and burning time (10 s) reflect significantly increased fire retardant performance of this disulfide compared to other compounds in this series as well as to Flamestab® NOR116. Finally, two new, phosphorus-based flame retardants were synthesized: P’P-diphenyl phosphinic hydrazide (PAH) and melamine phenyl phosphonate (MPhP). The DIN 4102-1 test and the more stringent UL94 vertical burning test (UL94 V) were used to assess the formulations ability to extinguish a flame once ignited. A very strong synergistic effect with azoalkanes was found, i.e. in combination with these radical generators even UL94 V0 rate could be obtained.

Energiapuun kastelu jätetäytön suotovedellä tuhkasta ja kompostista valmistetussa kasvualustassa

Tässä työssä tutkitaan suotoveden käsittelyä käyttämällä sitä kierrätysmateriaaleista valmistetussa tuhkamullassa loppusijoitusalueen päällä kasvatettavan energiapuukasvuston kasteluun. Kyseisen toimintamallin tarkoituksena on haihduttaa suotovettä energiapuiden avulla sekä sitouttaa ravinteita ja haitta-aineita sekä kasvustoon että kasvualustaan. Tavoitteena on selvittää toimintamallin hyödyntämiskelpoisuus ja tehokkuus suotovesien käsittelymenetelmänä sekä kastelun vaikutukset energiapuun kasvuun. Työssä suoritettiin kesän ja syksyn 2014 aikana energiapuun kastelukoe Mustankorkea Oy:n jätteenkäsittelykeskuksen alueella Jyväskylässä. Kokeessa loppusijoitusalueen päälle istutettuja eri kasvuvaiheissa olevia energiapajukasvustoja sekä hybridihaapakasvustoa kasteltiin jätetäytön suotovedellä. Kokeessa käytettiin kasvualustoina tuhkamultaa, joka oli valmistettu tuhkasta, kompostista ja ylijäämämaa- aineksesta, sekä kompostia. Kasteluveden, valumavesien, kasvualustojen ja pajukasvuston ominaisuuksia seurattiin kokeen aikana analyysien avulla. Lisäksi alueen vesitaseen selvittämiseksi suoritettiin lysimetrikokeet, joissa lysimetreihin istutettuja pajuja kasteltiin suotovedellä sekä hanavedellä. Tulosten perusteella suotovesikastelu lisäsi sekä pajun että haavan kasvua. Kastelu lisäsi pajun ravinnepitoisuuksia. Se myös heikensi hieman pajun poltto-ominaisuuksia. Kasvualustan ominaisuuksiin kastelulla ei havaittu olevan vaikutuksia. Kastelumäärä, jota voidaan käyttää ilman valumia, on kokeen perusteella n. 100–600 mm/kasvukausi käytetyllä kastelujärjestelmällä. Kastelujärjestelmää kehittämällä on kuitenkin luultavasti mahdollista lisätä haihduntaa ja siten kastelumäärää merkittävästi.

Geochemistry and water quality of Lake Qarun, Egypt

Water geochemistry is a very important tool for studying the water quality in a given area. Geology and climate are the major natural factors controlling the chemistry of most natural waters. Anthropogenic impacts are the secondary sources of contamination in natural waters. This study presents the first integrative approach to the geochemistry and water quality of surface waters and Lake Qarun in the Fayoum catchment, Egypt. Moreover, geochemical modeling of Lake Qarun was firstly presented. The Nile River is the main source of water to the Fayoum watershed. To investigate the quality and geochemistry of this water, water samples from irrigation canals, drains and Lake Qarun were collected during the period 2010‒2013 from the whole Fayoum drainage basin to address the major processes and factors governing the evolution of water chemistry in the investigation area. About 34 physicochemical quality parameters, including major ions, oxygen isotopes, trace elements, nutrients and microbiological parameters were investigated in the water samples. Multivariable statistical analysis was used to interpret the interrelationship between the different studied parameters. Geochemical modeling of Lake Qarun was carried out using Hardie and Eugster’s evolutionary model and a model simulated by PHREEQC software. The crystallization sequence during evaporation of Lake Qarun brine was also studied using a Jänecke phase diagram involving the system Na‒K‒Mg‒ Cl‒SO4‒H2O. The results show that the chemistry of surface water in the Fayoum catchment evolves from Ca- Mg-HCO3 at the head waters to Ca‒Mg‒Cl‒SO4 and eventually to Na‒Cl downstream and at Lake Qarun. The main processes behind the high levels of Na, SO4 and Cl in downstream waters and in Lake Qarun are dissolution of evaporites from Fayoum soils followed by evapoconcentration. This was confirmed by binary plots between the different ions, Piper plot, Gibb’s plot and δ18O results. The modeled data proved that Lake Qarun brine evolves from drainage waters via an evaporation‒crystallization process. Through the precipitation of calcite and gypsum, the solution should reach the final composition "Na–Mg–SO4–Cl". As simulated by PHREEQC, further evaporation of lake brine can drive halite to precipitate in the final stages of evaporation. Significantly, the crystallization sequence during evaporation of the lake brine at the concentration ponds of the Egyptian Salts and Minerals Company (EMISAL) reflected the findings from both Hardie and Eugster’s evolutionary model and the PHREEQC simulated model. After crystallization of halite at the EMISAL ponds, the crystallization sequence during evaporation of the residual brine (bittern) was investigated using a Jänecke phase diagram at 35 °C. This diagram was more useful than PHREEQC for predicting the evaporation path especially in the case of this highly concentrated brine (bittern). The predicted crystallization path using a Jänecke phase diagram at 35 °C showed that halite, hexahydrite, kainite and kieserite should appear during bittern evaporation. Yet the actual crystallized mineral salts were only halite and hexahydrite. The absence of kainite was due to its metastability while the absence of kieserite was due to opposed relative humidity. The presence of a specific MgSO4.nH2O phase in ancient evaporite deposits can be used as a paleoclimatic indicator. Evaluation of surface water quality for agricultural purposes shows that some irrigation waters and all drainage waters have high salinities and therefore cannot be used for irrigation. Waters from irrigation canals used as a drinking water supply show higher concentrations of Al and suffer from high levels of total coliform (TC), fecal coliform (FC) and fecal streptococcus (FS). These waters cannot be used for drinking or agricultural purposes without treatment, because of their high health risk. Therefore it is crucial that environmental protection agencies and the media increase public awareness of this issue, especially in rural areas.