Effects of early compost application on no-till organic soybean

Weed control has always been an important issue in agriculture. With the advent of no-till systems, soil erosion was reduced but herbicide use was increased. Organic no-till systems try to adjust reduced erosion to the no use of herbicides. Nevertheless, this adjustment is limited by the cost of mechanical weed control. This cost may be reduced by improved cultural weed control with cover crops mulches. In this paper we report a study on the application of compost manure on an oats winter cover crop, preceding soybean, instead of on the soybean summer crop. Treatments comprised a control without compost manure, and compost manure doses of 4 and 8 Mg ha-1 applied either on oats in winter or soybean in summer, organized in a randomized block design, with five replications. In summer, plots were split into weed-controlled or not controlled subplots. The timing of application and the manure doses did not affect the oats biomass or the soybean performance. However, in summer, without water stress, the application of manure at 8 Mg ha-1 directly on soybean has reduced weed biomass in this crop.

Management of Bidens pilosa and Commelina benghalensis in organic corn cultivation under no-tillage

Mowing is one of the most important methods used to control weeds in organic farming, under the no-tillage system. This study aimed to evaluate the effects of three weed management techniques on weed development, using the weeds Bidens pilosa and Commelina benghalensis, in competition with organic corn {mowing at the three-leaf stage (14 days after corn emergence - DACE), mowing at the three- and six-leaf stage (14 and 25 DACE), and no mowing. Single cultivation with no mowing was also evaluated for these weeds. Mowings performed at 14 and 25 DACE prevented the production of B. pilosa seeds, ensuring efficient control of this species. However, the use of this technique was shown to be inefficient in the control of C. benghalensis.

Population density and weed infestation in organic no-tillage corn cropping system under different soil covers

Currently, one of the biggest challenges faced by organic no-tillage farming is weed control. Thus, the use of cropping practices that help in the control of weeds is extremely important. The objective of this study was to evaluate population density and level of weed infestation in an organic no-tillage corn cropping system under different soil covers. The experiment was conducted in a randomized block design with six repetitions and five treatments, consisting of three soil covers in an organic no-tillage system, and an organic and a conventional system, both without soil cover. The treatments with soil cover used a grass species represented by the black oat, a leguminous species represented by the white lupine, and intercropping between both species. Corn was sown with spacing of 1.0 m between rows and 0.20 m between plants, using the commercial hybrid AG 1051. Infestation in corn was evaluated at stages V5 and V10, and weed density was evaluated at stage V5. The use of black oat straw alone or intercropped with white lupine, in the organic no-tillage corn cropping system, reduced the percentage of weed infestation and absolute weed density. Management-intensive systems and systems without soil cover showed higher relative densities for species Oxalis spp., Galinsoga quadriradiata and Stachys arvensis. The species Cyperus rotundus showed the highest relative density on organic no-tillage corn cropping systems. Black oat straw in the organic no-tillage cropping system limited the productive potential of corn.

Decentralized management of organic household wastes in the Kathmandu Valley using small-scale composting reactors

The sustainable management of municipal solid waste in the Kathmandu Valley has always been a challenging task. Solid waste generation has gone rapidly high in the Kathmandu Valley over the last decade due to booming population and rapid urbaniza-tion. Finding appropriate landfill sites for the disposal of solid wastes generated from the households of the Kathmandu Valley has always been a major problem for Nepalese government. 65 % of total generated wastes from the households of Nepal consist of organic materials. As large fractions of generated household wastes are organic in na-ture, composting can be considered as one of the best sustainable ways to recycle organ-ic wastes generated from the households of Nepal. Model Community Society Development (MCDS), a non-governmental organization of Nepal carried out its small-scale project in five households of the Kathmandu Valley by installing composting reactors. This thesis is based on this small-scale project and has used secondary data provided by MCDS Nepal for carrying out the study. Proper man-agement of organic wastes can be done at household levels through the use of compost-ing reactors. The end product compost can be used as soil conditioners for agricultural purposes such as organic farming, roof-top farming and gardening. The overall average organic waste generation in the Kathmandu Valley is found to be 0,23 kg/person/day and the total amount of organic household wastes generated in the Kathmandu Valley is around 210 Gg/yr. Produced composts from five composting reac-tors contain high amount of moistures but have sufficient amount of nutrients required for the fertility of land and plant growth. Installation of five composting reactors in five households have prevented 2,74 Mg of organic wastes going into the landfills, thus re-ducing 107 kg of methane emissions which is equivalent to 2,7 Mg of carbondioxide.

Comparative lifecycle assessment on organic and conventional carrots – case: Carrots from South-Savo and imported carrots from Italy

Organic farming is perceived to be an environmental friendly method of food production, thus assumed to be an alternative means of minimizing food-based environmental footprints. However, lower yield and unproductive years in organic crop rotation raise questions of whether it is really an environmentally friendly farming practice. Thus, the aim of this thesis was to examine the carbon footprint and energy demands of organic carrots cultivated and sold in South-Savo, Finland and compare them with those of local and imported conventional carrots using lifecycle assessment (LCA) as a method. From the investigation, it was found that organic carrots produced in South-Savo have the lowest GHG emissions and energy demand. The GHG emissions of local organic, local conventional and imported conventional carrots were found to be 4g CO2 eq. kgcarrots-1, 142g CO2 eq. kgcarrots-1 and 280 g CO2 eq. kgcarrots-1, respectively. On the other hand, energy demand for those carrots was found to be 1,33 MJ, 1,88 MJ and 3,68 MJ kgcarrots-1. Furthermore, it was also found that local organic carrots would have approximately similar GHG emissions as conventional counterpart if soil carbon stock change was excluded from the study.

Working fluid selection and design of small-scale waste heat recovery systems based on organic Rankine cycles

Demand for the use of energy systems, entailing high efficiency as well as availability to harness renewable energy sources, is a key issue in order to tackling the threat of global warming and saving natural resources. Organic Rankine cycle (ORC) technology has been identified as one of the most promising technologies in recovering low-grade heat sources and in harnessing renewable energy sources that cannot be efficiently utilized by means of more conventional power systems. The ORC is based on the working principle of Rankine process, but an organic working fluid is adopted in the cycle instead of steam. This thesis presents numerical and experimental results of the study on the design of small-scale ORCs. Two main applications were selected for the thesis: waste heat re- covery from small-scale diesel engines concentrating on the utilization of the exhaust gas heat and waste heat recovery in large industrial-scale engine power plants considering the utilization of both the high and low temperature heat sources. The main objective of this work was to identify suitable working fluid candidates and to study the process and turbine design methods that can be applied when power plants based on the use of non-conventional working fluids are considered. The computational work included the use of thermodynamic analysis methods and turbine design methods that were based on the use of highly accurate fluid properties. In addition, the design and loss mechanisms in supersonic ORC turbines were studied by means of computational fluid dynamics. The results indicated that the design of ORC is highly influenced by the selection of the working fluid and cycle operational conditions. The results for the turbine designs in- dicated that the working fluid selection should not be based only on the thermodynamic analysis, but requires also considerations on the turbine design. The turbines tend to be fast rotating, entailing small blade heights at the turbine rotor inlet and highly supersonic flow in the turbine flow passages, especially when power systems with low power outputs are designed. The results indicated that the ORC is a potential solution in utilizing waste heat streams both at high and low temperatures and both in micro and larger scale appli- cations.

Interfacial effects in organic solar cells

Solceller baserade på organiska halvledare erbjuder en möjlighet till storskalig och billig solenergiproduktion. Organiska halvledare har den fördelen att de är lösningsprocesserbara vilket gör att solceller och andra elektroniska komponenter baserade på dessa halvledare kan tillverkas vid låga temperaturer och med liten energiförbrukning. Nackdelen med dessa material är deras strukturella och energetiska oordning som leder till lägre effektivitet. För att organiska solceller ska kunna kommersialiseras krävs grundläggande insikter i de olika processer som begränsar effektiviteten. En stor del av forskningen om dessa processer har varit fokuserad kring egenskaperna av solcellens olika komponenter (de aktiva materialen) som sådana, medan gränsytorna mellan olika material har fått mindre uppmärksamhet. Gränsytor mellan olika material har distinkt olika egenskaper jämfört med ett rent material, och gränsytors olika egenskaper kan ha en väldigt stor inverkan på hur solcellerna fungerar. Syftet med denna avhandling är att klargöra några olika gränsyterelaterade effekter i organiska dioder och solceller. De gränsytor som behandlas är gränsytan mellan kontakten och det aktiva lagret (metall-organisk) och gränsytan mellan donor och acceptor (organisk-organisk). Resultaten visar att metall-organiska gränsytor måste designas noggrant för att begränsa förlust av effektivitet. En icke-idealisk kontakt leder till starkt reducerad effektivitet på grund av att elektronerna extraheras ineffektivt. Även till synes idealiska kontakter kan orsaka förluster genom spontan laddningsöverföring från metallen till det organiska lagret som effektivt sett minskar på den spänning som cellen kan alstra. Den organisk-organiska gränsytan påverkar hur mycket ström cellen kan alstra och beroende på gränsytans beskaffenhet kan de negativa rekombinationsprocesserna i materialet kontrolleras. ------------------------------------------------- Orgaanisille puolijohteille perustuvat aurinkokennot mahdollistavat suurimuotoisen ja edullisen aurinkoenergiatuotannon. Orgaanisten puolijohteiden etu on että ne voidaan liuottaa, jolloin aurinkokennot ja muut näille johteille perustuvat elektroniset komponentit voidaan valmistaa alhaisessa lämpötilassa kuluttaen vähän energiaa. Materiaalien huonona puolena on kuitenkin niiden rakenteellinen ja energeettinen epäjärjestys, jonka seurauksena niiden tehokkuus on huonompi. Orgaanisten aurinkokennojen kaupallistaminen edellyttää perustavanlaatuista ymmärystä tehokkuutta rajoittavista prosesseista. Aurinkokennotutkimus on pääosin keskittynyt aurinkokennon eri komponenttien (aktiivisten materiaalien) ominaisuuksiin, kun taas eri materiaalien rajapinnat ovat jääneet vähemmälle huomiolle. Eri materiaalien välisillä rajapinnoilla on huomattavan erilaisia ominaisuuksia verrattuna puhtaisiin materiaaleihin. Rajapintojen ominaisuudet voivat kuitenkin vaikuttaa merkittävästi aurinkokennojen toimintaan. Tämän väitöstutkimuksen tarkoituksena on selventää joitain rajapintoihin liittyviä toimintoja orgaanisissa diodeissa ja aurinkokennoissa. Käsiteltävät rajapinnat ovat rajapinta kontaktin ja aktiivisen kerroksen välillä (metallis-orgaaninen) ja rajapinta donorin ja akseptorin välillä (orgaanis-orgaaninen). Tutkimustulokset osoittavat, että metallis-orgaaniset rajapinnat tulee suunnitella huolellisesti, jotta tehokkuuden alenemista voidaan rajoittaa. Mikäli kontakti ei ole ideaalisti suunniteltu, vähenee tehokkuus huomattavasti, mikä johtuu elektronien tehottomasta ekstrahoinnista. Jopa ideaalisilta vaikuttavat kontaktit voivat johtaa tehokkuuden alenemiseen, mikäli varaus siirtyy spontaanisti metallista orgaaniseen kerrokseen, sillä tämä alentaa jännitettä jonka kenno voi tuottaa. Kennon orgaanis-orgaaninen rajapinta vaikuttaa siihen, kuinka paljon virtaa kenno pystyy tuottamaan. Rajapinnan ominaisuuksista riippuen materiaalin rekombinaatio on hallittavissa.

Persistent organic pollutants in sediments and fish from Lake Victoria, Uganda

This thesis describes the occurrence and sources of selected persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and hexachlorocyclohexanes (HCHs) in the northern watershed of Lake Victoria. Sediments and fish were collected from three highly polluted embayments (i.e. Murchison Bay, Napoleon Gulf and Thurston Bay) of the lake. The analysis for PCDD/Fs, PCBs and PBDEs was done using a high resolution mass spectrometer coupled to a gas chromatograph (GC), and a GC equipped with an electron capture detector was used for HCHs. Total (Σ) PCDD/Fs, PCBs and PBDEs in sediments ranged from 3.19 to 478, 313 to 4325 and 60.8 to 179 pg g-1 dry weight (dw), respectively. The highest concentrations of pollutants were found at sites close to industrial areas and wastewater discharge points. The maximum concentrations of PCDD/Fs, PCBs, PBDEs and HCHs in fish muscle homogenates were 49, 779, 495 and 45,900 pg g-1 wet weight (ww), respectively. The concentrations of the pollutants in Nile perch (Lates niloticus) were significantly greater than those in Nile tilapia (Oreochromis niloticus), possibly due to differences in trophic level and dietary feeding habits among fish species. World Health Organization-toxic equivalency quotient (WHO2005-TEQ) values in the sediments were up to 4.24 pg g-1 dw for PCDD/Fs and 0.55 pg TEQ g-1 dw for the 12 dioxin-like PCBs (dl-PCBs). 23.1% of the samples from the Napoleon Gulf were above the interim sediment quality guideline value of 0.85 pg WHO-TEQ g-1 dw set by the Canadian Council for Ministers of the Environment. The WHO2005-TEQs in fish were 0.001-0.16 pg g-1 for PCDD/Fs and 0.001-0.31 pg g-1 ww for dl- PCBs. The TEQ values were within a permissible level of 3.5 pg g−1 ww recommended by the European Commission. Based on the Commission set TEQs and minimum risk level criteria formulated by the Agency for Toxic Substances and Disease Registry, the consumption of fish from Lake Victoria gives no indication of health risks associated to PCDD/Fs and PCBs. Principal component analysis (PCA) indicated that anthropogenic activities such as agricultural straw open burning, medical waste incinerators and municipal solid waste combustors were the major sources of PCDD/Fs in the watershed of Lake Victoria. The ratios of α-/γ-HCH varied from 0.89 to 1.68 suggesting that the highest HCH residues mainly came from earlier usage and fresh γ-HCH (lindane). In the present study, the concentration of POPs in fish were not significantly related to those in sediments, and the biota sediment accumulation factor (BSAF) concept was found to be a poor predictor of the bioavailability and bioaccumulation of environmental pollutants.

Can organic and transgenic soy be used as a substitute for animal protein by rats?

We evaluated the protein quality of organic and transgenic soy fed to rats throughout life. Thirty female Wistar rats were divided into three groups (N = 10): organic soy group (OSG) receiving organic soy-based diet, genetically modified soy group (GMSG) receiving transgenic soy-based diet, and a control group (CG) receiving casein-based diet. All animals received water and isocaloric diet (10% protein), ad libitum for 291 days. After this, the weight of GMSG animals (290.9 ± 9.1 g) was significantly lower (P <= 0.04) than CG (323.2 ± 7.9 g). The weight of OSG (302.2 ± 8.7 g) was between that of the GMSG and the CG. Protein intake was similar for OSG (308.4 ± 6.8 g) and GMSG (301.5 ± 2.5 g), and significantly lower (P <= 0.0005) than the CG (358.4 ± 8.1 g). Growth rate was similar for all groups: OSG (0.80 ± 0.02 g), GMSG (0.81 ± 0.03 g) and CG (0.75 ± 0.02 g). In addition to providing a good protein intake and inducing less weight gain, both types of soy were utilized in a manner similar to that of casein, suggesting that the protein quality of soy is similar to that of the standard protein casein. The groups fed soy-based diet gained less weight, which may be considered to be beneficial for health. We conclude that organic and transgenic soy can be fed throughout life to rats in place of animal protein, because contain high quality protein and do not cause a marked increase in body weight.

Karboksyylihappojen kromatografinen fraktiointi

Suurin osa alifaattisista karboksyylihapoista tuotetaan nykyään synteettisesti, mutta öljyn hinnan nousu ja ekologisempi ajattelutapa on aiheuttanut kiinnostusta tuottaa näitä karboksyyli- ja hydroksihappoja jatkossa fermentoimalla tai sellun valmistuksen sivuvirtana syntyvästä mustalipeästä. Nykyään mustalipeä poltetaan sellaisenaan soodakattiloissa keittokemikaalien regeneroimiseksi, energiaksi ja sähköksi. Jatkossa mustalipeästä voisi erottaa arvokkaat orgaaniset hapot ennen polttamista. Saadusta happoseoksesta tulisi erottaa yksittäiset alifaattiset karboksyylihapot toisistaan jatkojalostusta varten. Tämän kandidaatintyön tavoitteena oli selvittää, millä kromatografisella erotusmenetelmällä fermentointituotteina ja teollisuuden sivuvirtoina syntyvistä karboksyylihapposeoksista saadaan yksittäiset alifaattiset karboksyylihapot erotettua toisistaan. Mittaukset suoritettiin kolonnilla, jossa hartsipedin halkaisija oli 1,5 cm ja korkeus 15 cm. Kolonnin erototusmateriaaleina kokeiltiin vahvoja ja heikkoja kationinvaihtohartseja, vahvaa anioninvaihtohartsia ja polymeerisiä adsorbentteja. Erotettavaksi happoseokseksi valittiin sitruuna-, viini-, glykoli-, maito- ja etikkahapon seos. Tehokkain erotus saatiin Puroliten valmistamalla Macronet 270:lla, joka on mikrohuokoinen polymeerinen adsorbentti. Macronet 270:lla saatiin erotettua erityisesti viini- ja glykolihappo sitruuna-, maito- ja etikkahaposta. Yksittäisiä happoja ei saatu kuitenkaan kunnolla erotettua. Parhaat koeolosuhteet erotustehokkuuden ja retentioaikojen kannalta saatiin vesieluentin virtausnopeudella 2 mL/min, syöttöpulssin tilavuudella 5 mL ja kolonnin lämpötilassa 75 °C.

Optical spectroscopy of organic material based on C60

The structure and optical properties of thin films based on C60 materials are studied. Reproducible vacuum method of thin fullerene films production with Cd impurity on Si, glass and mica surfaces is developed. Surface morphology of the films are investigated by AFM and SEM methods. The ab initio quantum - chemical calculations of the geometry, total energy and excited energy states of complex fullerene- cadmium telluride supramolecules are performed. Photoluminescence spectra of composite thin films based on C60 before and after X-ray irradiation were measured. The intensity of additional peaks is defined as the charge composition due to the type of substrate. These results are interpreted as an appearance of the dipole-allowed transitions in the fullerene excited singlet states spectrum cause of an interference with cadmium telluride. X-ray irradiated films were investigated, and additional peaks in photoluminescence spectra were detected. These peaks appear as a result of molecular complexes formation from C60CdTe mixture and dimerization of the films. Density functional B3LYP quantum-chemical calculations for C60CdTe, molecular complexes, (C60)2 and C120O dimers were performed to elucidate some experimental results.

Comparative effects of organic and inorganic mercury on in vivo dopamine release in freely moving rats

The present study was carried out in order to compare the effects of administration of organic (methylmercury, MeHg) and inorganic (mercury chloride, HgCl 2 ) forms of mercury on in vivo dopamine (DA) release from rat striatum. Experiments were performed in conscious and freely moving female adult Sprague-Dawley (230-280 g) rats using brain microdialysis coupled to HPLC with electrochemical detection. Perfusion of different concentrations of MeHg or HgCl 2 (2 µL/min for 1 h, N = 5-7/group) into the striatum produced significant increases in the levels of DA. Infusion of 40 µM, 400 µM, or 4 mM MeHg increased DA levels to 907 ± 31, 2324 ± 156, and 9032 ± 70% of basal levels, respectively. The same concentrations of HgCl 2 increased DA levels to 1240 ± 66, 2500 ± 424, and 2658 ± 337% of basal levels, respectively. These increases were associated with significant decreases in levels of dihydroxyphenylacetic acid and homovallinic acid. Intrastriatal administration of MeHg induced a sharp concentration-dependent increase in DA levels with a peak 30 min after injection, whereas HgCl 2 induced a gradual, lower (for 4 mM) and delayed increase in DA levels (75 min after the beginning of perfusion). Comparing the neurochemical profile of the two mercury derivatives to induce increases in DA levels, we observed that the time-course of these increases induced by both mercurials was different and the effect produced by HgCl 2 was not concentration-dependent (the effect was the same for the concentrations of 400 µM and 4 mM HgCl 2 ). These results indicate that HgCl 2 produces increases in extracellular DA levels by a mechanism differing from that of MeHg.

Enhanced production and organic solvent stability of a protease fromBrevibacillus laterosporus strain PAP04

A bacterial strain (PAP04) isolated from cattle farm soil was shown to produce an extracellular, solvent-stable protease. Sequence analysis using 16S rRNA showed that this strain was highly homologous (99%) to Brevibacillus laterosporus. Growth conditions that optimize protease production in this strain were determined as maltose (carbon source), skim milk (nitrogen source), pH 7.0, 40°C temperature, and 48 h incubation. Overall, conditions were optimized to yield a 5.91-fold higher production of protease compared to standard conditions. Furthermore, the stability of the enzyme in organic solvents was assessed by incubation for 2 weeks in solutions containing 50% concentration of various organic solvents. The enzyme retained activity in all tested solvents except ethanol; however, the protease activity was stimulated in benzene (74%) followed by acetone (63%) and chloroform (54.8%). In addition, the plate assay and zymography results also confirmed the stability of the PAP04 protease in various organic solvents. The organic solvent stability of this protease at high (50%) concentrations of solvents makes it an alternative catalyst for peptide synthesis in non-aqueous media.

Organic acid profile of commercial sour cassava starch

Organic acids are present in sour cassava starch ("polvilho azedo") and contribute with organoleptic and physical characteristics like aroma, flavor and the exclusive baking property, that differentiate this product from the native cassava starch. Samples of commercial sour cassava starch collected in South and Southeast Brazil were prepared for high performance liquid chromatography (HPLC) analysis. The HPLC equipment had a Biorad Aminex HPX-87H column for organic acid analysis and a refractometric detector. Analysis was carried out with 0.005M sulfuric acid as mobile phase, 0.6ml/min flow rate and column temperature of 60° C. The acids quantified were lactic (0.036 to 0.813 g/100g), acetic (0 to 0.068 g/100g), propionic (0 to 0.013 g/100g) and butyric (0 to 0.057 g/100g), that are produced during the natural fermentation of cassava starch. Results showed large variation among samples, even within the same region. Some samples exhibited high acid levels, mainly lactic acid, but in these neither propionic nor butyric acids were detected. Absence of butyric acid was not expected because this is an important component of the sour cassava starch aroma, and the lack of this acid may suggest that such samples were produced without the natural fermentation step.

Effect of heat input on the mechanical properties of welded joints in high strength steels

Experiments were carried out to determine the properties of the welded joints in 8mm thick high-strength steels produced by quenching and tempering and thermomechanical rolling with accelerated cooling (tensile strength 821–835 MPa). The dependence of the strength, elongation, hardness, impact energy and crack opening displacement on the heat input in the range 1.0–0.7 kJ mm21 was determined. The results show that the dependence of the strength of the welded joints decreases and that of the elongation increases. The heat input has only a slight effect on the impact energy and crack opening displacement in the heat-affected zone.