Growth, biomass allocation and photosynthesis of Rolandra fruticosa (asteraceae) in response to shade

The effects of shade on growth, biomass allocation patterns and photosynthetic response was examined for Rolandra fruticosa (L.) Kuntze, a common perennial weed shrub in cultivated pastures and agricultural areas of Brazilian Amazonia, for plants grown in full sunlight and those shaded to 30 % of full sunlight over a 34-d period. Specific leaf area and leaf area ratio were higher for shade plants during all the experimental period. Shade plants allocated significantly less biomass to root tissue than sun plants and relative growth rate was higher in sun plants. Sun leaves had significantly higher dark respiration and light saturated rates of photosynthesis than shade leaves. The apparent quantum efficiency was higher for shade leaves, while light compensation point was higher for sun leaves. These results are discussed in relation to their ecological and weed management implications.

Greenhouse gas emissions from peat and biomass-derived fuels, electricity and heat — Estimation of various production chains by using LCA methodology

More discussion is required on how and which types of biomass should be used to achieve a significant reduction in the carbon load released into the atmosphere in the short term. The energy sector is one of the largest greenhouse gas (GHG) emitters and thus its role in climate change mitigation is important. Replacing fossil fuels with biomass has been a simple way to reduce carbon emissions because the carbon bonded to biomass is considered as carbon neutral. With this in mind, this thesis has the following objectives: (1) to study the significance of the different GHG emission sources related to energy production from peat and biomass, (2) to explore opportunities to develop more climate friendly biomass energy options and (3) to discuss the importance of biogenic emissions of biomass systems. The discussion on biogenic carbon and other GHG emissions comprises four case studies of which two consider peat utilization, one forest biomass and one cultivated biomasses. Various different biomass types (peat, pine logs and forest residues, palm oil, rapeseed oil and jatropha oil) are used as examples to demonstrate the importance of biogenic carbon to life cycle GHG emissions. The biogenic carbon emissions of biomass are defined as the difference in the carbon stock between the utilization and the non-utilization scenarios of biomass. Forestry-drained peatlands were studied by using the high emission values of the peatland types in question to discuss the emission reduction potential of the peatlands. The results are presented in terms of global warming potential (GWP) values. Based on the results, the climate impact of the peat production can be reduced by selecting high-emission-level peatlands for peat production. The comparison of the two different types of forest biomass in integrated ethanol production in pulp mill shows that the type of forest biomass impacts the biogenic carbon emissions of biofuel production. The assessment of cultivated biomasses demonstrates that several selections made in the production chain significantly affect the GHG emissions of biofuels. The emissions caused by biofuel can exceed the emissions from fossil-based fuels in the short term if biomass is in part consumed in the process itself and does not end up in the final product. Including biogenic carbon and other land use carbon emissions into the carbon footprint calculations of biofuel reveals the importance of the time frame and of the efficiency of biomass carbon content utilization. As regards the climate impact of biomass energy use, the net impact on carbon stocks (in organic matter of soils and biomass), compared to the impact of the replaced energy source, is the key issue. Promoting renewable biomass regardless of biogenic GHG emissions can increase GHG emissions in the short term and also possibly in the long term.

Fate of fuel-bound nitrogen and sulfur in biomass-fired Industrial boilers

Användning av biomassa som energikälla för produktion av el och värme är ett sätt att minska beroendet av fossila bränslen och höja självförsörjningen av energi. Fossila bränslen är den främsta källan till koldioxid utsläpp förorsakad av människan. Biomassa, å andra sidan, betraktas som en koldioxidneutral energikälla. Svavlet och kvävet i biomassan bildar dock föroreningar såsom kväveoxider (NOX) och svaveldioxid (SO2), som bidrar till försurning av mark och sjöar. Svavlet i bränslet kan även både förorsaka och förhindra korrosion i en förbränningsanläggning, beroende på förbränningen och bränslet. Huvudsyftet med detta arbete var att få en bättre förståelse om hur utsläppen av NOX och SO2 bildas från bränslebundet kväve och svavel vid förbränning av olika biobränslen. Mätkampanjer i fullskaliga förbränningsanläggningar utfördes, där gassammansättningen mättes i eldstaden och rökgasen. Förståelsen om gaskemin i eldstaden är viktig, för att möjliggöra utvecklandet av renare och effektivare förbränningsanläggningar. Ett annat syfte med arbetet var att klargöra om sulfatering av askkomponenter vid förbränning av biobränslen med olika askegenskaper. Alkaliklorider som bildas vid biomassaförbränning kan orsaka korrosion av värmeöverföringsytor. Svavlet i bränslet visade sig ha en viktig roll i att sulfatera alkaliklorider till mindre korrosiva alkalisulfater. Närvaron av gasformig svavelsyra i rökgaskanalen av förbränningsanläggningar studerades även. Kondensering av svavelsyra leder till korrosion av rökgaskanalen och dess delar. Om svavelsyrakoncentrationen i rökgasen är känd, kan daggpunktstemperaturen beräknas och kondensering av svavelsyra förhindras. I arbetet utvecklades en mätmetod för att mäta låga koncentrationer av gasformig svavelsyra i rökgaser. Denna metod användes för att undersöka risken av lågtemperaturkorrosion orsakad av svavelsyra i förbränningsanläggningar. ------------------------------------------------------------------------------------------------------------ Käyttämällä biomassaa energianlähteenä voidaan vähentää sähkön- ja lämmöntuotannon riippuvuutta fossiilisiin polttoaineisiin. Biomassan käytöllä voidaan myös lisätä energiantuotannon omavaraisuutta. Fossiiliset polttoaineet ovat pääasiallinen syy ihmisen aiheuttamiin hiilidioksidipäästöihin. Biomassa sen sijaan luetaan hiilidioksidineutraaleihin energianlähteisiin. Biopolttoaineiden käytössä tosin vapautuu typpi- ja rikkioksideja, jotka edesauttavat maaperän ja merien happamoitumista. Lisäksi biopolttoaineen rikki voi sekä vähentää että aiheuttaa laitteiden korroosiota energiantuotannossa riippuen biopolttoaineesta ja palamisesta. Tämän työn päätavoitteena oli selvittää mitä biopolttoaineeseen sitoutuneelle typelle ja rikille tapahtuu teollisissa polttolaitoksissa. Kyseisten oksidien muodostumista tutkittiin polttamalla eri biomassoja polttolaitoksissa. Tutkimukset toteutettiin mittauskampanjoilla useissa polttolaitoksissa. Kaasujen koostumusta mitattiin sekä tulipesässä, että savukaasuista. Kaasujen koostumus varsinkin tulipesässä on tärkeää, jotta tulevaisuudessa voidaan rakentaa puhtaampia ja tehokkaampia polttolaitoksia. Työn toisena tavoitteena oli selvittää biomassan polton yhteydessä tapahtuvaa tuhkan sulfatoitumista. Alkalikloridit, joita muodostuu biomassan poltossa, voivat aiheuttaa lämmönsiirtopintojen korroosiota. Rikki osoittautui tärkeäksi osaksi prosessia, jossa korroosiota aiheuttavat alkalikloridit sulfatoituivat vähemmän korrosoiviksi alkalisulfaateiksi. Myös kaasumaisen rikkihapon läsnäoloa savukaasuissa tutkittiin. On todettu, että kaasumuotoinen rikkihappo johtaa korroosioon savukaasukanavan kylmässä päässä ja sen eri osissa rikkihapon tiivistyessä lämpötilan laskiessa. Mikäli rikkihapon pitoisuus savukaasussa tiedetään, sen kastepiste voidaan laskea ja tiivistyminen estää. Tässä työssä kehitettiin mittausmenetelmä rikkihapon alhaisten pitoisuuksien mittaamiseen. Menetelmää hyödynnettiin polttolaitoksissa, joissa tutkittiin rikkihapon tiivistymisestä johtuvaa korroosiota.

Effect of plant row spacing and herbicide use on weed aboveground biomass and corn grain yield

The use of narrow plant spacing in corn (Zea mays) has been suggested as a technological alternative to obtain grain yield increases, due to a better use of resources. The regular pattern could diminish intraspecific competition while favoring interspecific competition with weeds. The objective of this study was to analyze the effect of corn row spacing on weed aboveground biomass and corn grain yield. Field experiments were conducted during 2002/2003 and 2003/2004 growing seasons. Three corn hybrids with two-row width (0.70 and 0.35 m) were tested. A greater photosynthetic photon flux density (PPFD) interception with a lower weed aboveground dry matter in narrow row arrangement was obtained. Corn grain yield was greater in the narrow row arrangement than in the wide row spacing. This increase in grain yield was related to a better resource use that allows for a reduced interspecific competition. The use of reduced spatial arrangement appeared to be an interesting alternative to increase both the grain yield potential and corn suppressive ability against weeds in corn dryland production systems.

Towards optimal fractionation of lignocellulosic biomass using switchable ionic liquids

En ny familj av reversibla (switchable) joniska vätskor (SIL) innehållande 1,8-diazobicyklo-[5.4.0]-undek-7-en (DBU), en molekyl innehållande en eller flera hydroxyl- grupper (t.ex. glycerol) och en sur gas (CO2, SO2) syntetiserades via en enkel procedur samt karakteriserades. [DBU][karbonat] eller [sulfonat] bildades ur en respektive icke-jonisk blandning av en molekylär, organisk polyol (eller ennan molekyl innehållande en OH-grupp) och en amidinbas under bubblandet av en sur gas. Därtill kunde den joniska vätskan omvandlas tillbaka till sina beståndsdelar med hjälp av att upphetta och/eller bubbla en inert gas såsom kväve genom vätskan. SIL- strukturerna kartlades med bl.a. NMR- och FTIR- spektroskopi. Omvandlingen från lågpolära (molekylära) vätskor till högpolära joniska vätskor (SIL) bekräftades även genom att observera förändringar i deras fysikaliska egenskaper, såsom viskositet och färg. Nedbrytningstemperaturerna hos SILs bestämdes med hjälp av termogravimetrisk analys (TGA) som antydde att nedbrytningstemperaturen hos de syntetiserade föreningarna log mellan 50 och 200oC. De nya joniska vätskorna uppvisade högre nedbrytningstemperaturer jämfört med i litteraturen tidigare förekommande exempel och kunde därför tillämpas på flera ändamål. Därtill, reversibla (switchable) joniska vätskor uppbyggda av bl.a. alkoholer, antingen hexanol eller butanol, och CO2 samt en amidin (DBU) användes vid upplösning och fraktionering av ved. Joniska vätskor syntetiserade ur glycerol och sura gaser tillsammans med amidiner användes även för fraktionering av andra lignocellulosor såsom färsk björk (Betula pendula). Björkflis utsattes för behandling, för en period på en till fem dagar vid 100oC och under atmosfäriskt tryck. Alla syntetiserade joniska vätskor visade sig vara relativt neutrala i avseende på upplösning och avlägsnandet av lignin. Slutligen, optimala fraktioneringprocessbetingelser för ved med reversibla joniska vätskor kartlades. Fraktionering av vedbiomassa med dessa joniska vätskor uppvisade sig att vara en selektiv och effektiv metod för extraktion av olika komponenter från lignocellulosa. Den olösta fraktionen hos en vedflis, närmast cellulosa, fibrillerades. -------------------------------------------------------------------------------------------------------------------- Tässä työssä kehitettiin perhe uuden tyyppisiä, reversiibeleitä (switchable) ioninesteitä ( SIL ) joka koostuvat orgaanisesta super-emäksestä kuten 1,8- diatsabisyklo [ 5.4.0] undek- 7-eeni (DBU ) ja yhden tai useampia hydroksyyliryhmiä sisältältävästä molekyylistä (esim. glyseroli) ja happamasta kaasusta (CO2 , SO2) yksinkertaisen menetelmän avulla. [DBU] [ karbonaatti] tai [sulfonaatti] syntetisoitiin kunkin lähtöaineen seoksista kuplittamalla seosta happamalla kaasulla jolloin eksoterminen reaktio tapahtui ja ioninen neste syntyi. Ioniset nesteet voitiin palauttaa takaisin lähtöaineseokseksi kuumentamalla ja/tai kuplittamalla neutraalia kaasua (esim. typpi) seoksen läpi. SIL rakenteet määritettiin ja niiden ominaisuudet kartoitettiin eri menetelmillä, mukaan lukien NMR- ja FTIR -spektroskopia. Ionisen, korkeapoläärisen nesteen syntyminen todennettiin myös viskositeettimittauksilla ja värinmuutoksilla käyttäen hyväksi polariteetti-indikaattoria (Nile red). Myös hajoamislämpötilat määritettiin termogravimetrisellä analyysillä (TGA) ja todettiin että syntetisoitujen yhdisteiden hajoamislämpötila oli välillä 50 ja 200oC . Näiden uusien reversiibeleiden ioninesteiden hajoamisämpötilat olivat korkeammat verrattuna kirjallisuudessa aikaisemmin mainittuihin esimerkkeihin joten niitä voidaan soveltaa useisiin tarkoituksiin. Myös ioninesteitä jotka sisälsivät primäärejä alkoholeja rakennusaineina syntetisoitiin ja hyödynnettiin puun fraktioinnissa. Männyn ja kuusen lisäksi tuoreita koivulastuja onnistuttiin fraktioimaan miedoissa olosuhteissa. Kaikkien syntetisoitujen ioninesteiden todettiin olevan suhteellisen neutraaleja ligniinin liuotuksen suhteen. Vielä, optimaaliset fraktiointiolosuhteet määritettiin ryhmälle reversiibeleitä ioninesteitä ja näiden uudenlaisten ioninesteiden todettiin olevan tehokkaita puun ja muiden lignoselluloosien eri fraktioiden liuotuksessa. Liukenematon osa puulastua joka oli lähinnä selluloosaa fibrilloitui.

Quality, Productivity and Economy in Welding Manufacturing - Case Study: West Africa

This thesis studies quality, productivity and economy in welding manufacturing in West African states such as Ghana, Nigeria and Cameroon. The study consists of two parts: the first part, which forms the theoretical background, reviews relevant literature concerning the metal and welding industries, and measurement of welding quality, productivity and economy. The second part, which is the empirical part, aims to identify activities in the metal manufacturing industries where welding is extensively used and to determine the extent of welding quality, productivity and economy measurements in companies operating in the metal manufacturing industries. Additionally, the thesis aims to identify challenges that companies face and to assess the feasibility of creating a network to address these issues. The research methods used in the empirical part are the case study (qualitative) method and the survey (quantitative) method. However, the case study method was used to elicit information from companies in Ghana, while the survey method was used to elicit information from companies in Nigeria and Cameroon. The study considers important areas that contribute to creating awareness and understanding of the current situation of the welding industry in West Africa. These areas include the metal manufacturing industrial sector, metal products manufactured, metal production and manufacturing systems deployed, welding quality, productivity and economy measurement systems utilized, equipment and materials on the markets, general challenges facing companies in welding operations, welding technology programs and research in local universities, and SWOT analysis of the various West African states. The notable findings indicate that majority of the companies operate in the constructionindustrial sector. Also, majority of the companies are project manufacturing oriented, thus provide services to customers operating in the growing industries such as the oil and gas, mining, food and the energy industry. In addition, only few companies are certified under standards such as ISO 9001, ISO 3834, and OHSAS 18001. More so, majority of the companies employ manual welding technique, and shielded metal arc welding (SMAW) as the commonly used welding process. Finally, welder salary is about € 300 / month as of June 2013 and the average operations turnover of medium to large companies is about € 5 million / year as at 2012. Based on analysis of the results of the study, it is noted that while welding activities are growing, the availability of cheap labor, the need for company and welder qualification and certification, and the need to manufacture innovative products through developmental projects (transfer of welding expertise and technology) remain as untapped opportunities in the welding industry in the West African states. The study serves as a solid platform for further research and concludes with several recommendations for development of the West African welding industry.

Pressure filtration characteristics of enzymatically hydrolyzed biomass suspensions

Enzymatic hydrolysis of lignocellulosic polymers is likely to become one of the key technologies enabling industrial production of liquid biofuels and chemicals from lignocellulosic biomass. Certain types of enzymes are able to hydrolyze cellulose and hemicellulose polymers to shorter units and finally to sugar monomers. These monomeric sugars are environmentally acceptable carbon sources for the production of liquid biofuels, such as bioethanol, and other chemicals, such as organic acids. Liquid biofuels in particular have been shown to contribute to the reduction of net emissions of greenhouse gases. The solid residue of enzymatic hydrolysis is composed mainly of lignin and partially degraded fibers, while the liquid phase contains the produced sugars. It is usually necessary to separate these two phases at some point after the hydrolysis stage. Pressure filtration is an efficient technique for this separation. Solid-liquid separation of biomass suspensions is difficult, because biomass solids are able to retain high amounts of water, which cannot be readily liberated by mechanical separation techniques. Most importantly, the filter cakes formed from biomaterials are compressible, which ultimately means that the separation may not be much improved by increasing the filtration pressure. The use of filter aids can therefore facilitate the filtration significantly. On the other hand, the upstream process conditions have a major influence on the filtration process. This thesis investigates how enzymatic hydrolysis and related process conditions affect the filtration properties of a cardboard suspension. The experimental work consists of pressure filtration and characterization of hydrolysates. The study provides novel information about both issues, as the relationship between enzymatic hydrolysis conditions and subsequent filtration properties has so far not been considered in academic studies. The results of the work reveal that the final degree of hydrolysis is an important factor in the filtration stage. High hydrolysis yield generally increases the average specific cake resistance. Mixing during the hydrolysis stage resulted in undefined changes in the physical properties of the solid residue, causing a high filtration resistance when the mixing intensity was high. Theoretical processing of the mixing data led to an interesting observation: the average specific cake resistance was observed to be linearly proportional to the mixer shear stress. Another finding worth attention is that the size distributions of the solids did not change very dramatically during enzymatic hydrolysis. There was an observable size reduction during the first couple of hours, but after that the size reduction was minimal. Similarly, the size distribution of the suspended solids remained almost constant when the hydrolyzed suspension was subjected to intensive mixing. It was also found that the average specific cake resistance was successfully reduced by the use of filter aids. This reduction depended on the method of how the filter aids were applied. In order to obtain high filtration capacity, it is recommended to use the body feed mode, i.e. to mix the filter aid with the slurry prior to filtration. Regarding the quality of the filtrate, precoat filtration was observed to produce a clear filtrate with negligible suspended solids content, while the body feed filtrates were turbid, irrespective of which type of filter aid was used.

Production of Chemicals from Woody Biomass by Wet Oxidation

The production of chemicals from sawdust by wet oxidation has been investigated. Two different concentrations of sawdust; 54054 mg/l and 32683 mg/l were used in the study. The wet oxidation operating conditions were; 175 deg.C – 225 deg.C, 1MPa Oxygen, and 40 minutes to 120 minutes reaction time. Carboxylic acids were among the chemicals produced in the process. The total yield of carboxylic acids was found to increase with temperature. Also, higher yields of carboxylic acids were observed at a lower sawdust concentration. This was probably due to the high oxygen-biomass ratio at lower sawdust concentration. Higher oxygen availability at low sawdust concentration resulted in increased conversion of the sawdust; hence the higher yields of carboxylic acids. At lower sawdust concentration, a total carboxylic acid yield of 25.59 wt% was attained at 200 deg.C and 40 minutes reaction time. At higher sawdust concentration, a total carboxylic acid yield of 15.57 wt% was attained at 200 deg.C and 40-minutes reaction time. The carboxylic acids identified include formic acid, acetic acid, succinic acid and oxalic acid. The optimum temperature for the production of formic acid was found to be 200 deg.C, while the optimum temperature for the production of acetic acid was found to be 225 deg.C. A temperature of 225 deg.C and relatively short reaction time of 10 minutes was found to be the optimal condition for the production of succinic acid. Formic acid was produced in the highest yield, with an optimal yield of 13.69wt %, when the reaction temperature and time are 200 deg.C and 40 minutes respectively. The yield of formic acid was found to decrease significantly when further increasing the temperature to 225 deg.C. This was presumably due to thermal decomposition of formic acid at relatively higher temperature. However, the yield of acetic acid was found to steadily increase with temperature. This is because acetic is more thermally stable than formic acid. The yield of acetic acid did not decrease after the temperature was increased to 225 deg.C. Optimal yield of acetic acid (7.98wt %) was achieved at; 225 deg.C, and 40 minutes reaction time. Succinic acid was produced only at temperatures of 200 deg.C and 225 deg.C. Optimal yield of succinic acid (5.66wt %) was attained under the following conditions; 32683 mg/l, 225 deg.C, 1MPa O2, and 10-minutes reaction time. Oxalic acid was produced in the lowest yield and, less frequently. The optimal yield of oxalic acid (4.02 wt%) was attained at 175 deg.C and 80-minutes of reaction time The Total Organic Carbon (TOC) is found to be higher when increasing the operating temperature, thus suggesting that more organic compounds are formed at higher temperatures. The identified carboxylic acids could only account for less than 30% of the measured COD content of the various wet oxidation samples. This implies that some other unidentified compounds (reaction products) must have been present. In general, wet oxidation seems to be an effective method for converting lignocellulosic biomass into useful chemicals. Relatively higher temperatures have been found to favor the production of carboxylic acids from sawdust.

Topochemistry of physical and chemical pretreatments of biomass as investigated by FE-SEM, XPS and ToF-SIMS

Surface chemistry is of great importance in plant biomass engineering and applications. The surface chemical composition of biomass which includes lignin, carbohydrates and extractives influences its interactions with chemical agents, such as pulp processing/papermaking chemicals, or enzymes for different purposes. In this thesis, the changes in the surface chemical composition of lignocellulosic biomass after physical modification for the improvement of resulting paper properties and chemical treatment for the enhancement of enzymatic hydrolysis were investigated. Low consistency (LC) refining was used as physical treatment of bleached softwood and hardwood pulp samples, and the surface chemistry of refined samples was investigated. The refined pulp was analysed as whole pulp while the fines-free fibre samples were characterized separately. The fines produced in LCrefining contributed to an enlarged surface specific area as well as the change of surface coverage by lignin and extractives, as investigated by X-ray photoelectron spectroscopy (XPS). The surface coverage by lignin of the whole pulp decreased after refining while the surface coverage by extractives increased both for pine and eucalyptus. In the case of pine, the removal of fines resulted in reduction of the surface coverage by extractives, while the surface coverage by lignin increased on fibre sample (without fines). In the case of eucalyptus, the surface coverage by lignin of fibre samples decreased after the removal of fines. In addition, the surface distribution of carbohydrates, lignin and extractives of pine and eucalyptus samples was determined by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). LC-refining increased the amounts of pentose, hexose and extractives on the surface of pine samples. ToF-SIMS also gave clear evidence about xylan deposition and reduction of surface lignin distribution on the fibre of eucalyptus. However, the changes in the surface chemical composition during the physical treatment has led to an increase in the adsorption of fluorescent whitening agents (FWAs) on fibres due to a combination of electro-static forces, specific surface area of fibres and hydrophobic interactions. Various physicochemical pretreatments were conducted on wood and non-wood biomass for enhancing enzymatic hydrolysis of polysaccharides, and the surface chemistry of the pretreated and enzymatically hydrolysed samples was investigated by field emission scanning electron microscopy (FE-SEM), XPS and ToF-SIMS. A hydrotrope was used as a relatively novel pretreatment technology both in the case of wood and non-wood biomass. For comparison, ionic liquid and hydrothermal pretreatments were applied on softwood and hardwood as well. Thus, XPS analysis showed that the surface lignin was more efficiently removed by hydrotropic pretreatment compared to ionic liquid or hydrothermal pretreatments. SEM analysis also found that already at room temperature the ionic liquid pretreatments were more effective in swelling the fibres compared with hydrotropic pretreatment at elevated temperatures. The enzymatic hydrolysis yield of hardwood was enhanced due to the decrease in surface coverage of lignin, which was induced by hydrotropic treatment. However, hydrotropic pretreatment was not appropriate for softwood because of the predominance of guaiacyl lignin structure in this material. In addition, the reduction of surface lignin and xylan during pretreatment and subsequent increase in cellulose hydrolysis by enzyme could be observed from ToF-SIMS results. The characterisation of the non-wood biomass (e.g. sugarcane bagasse and common reed) treated by hydrotropic method, alkaline and alkaline hydrogen peroxide pretreatments were carried out by XPS and ToF-SIMS. According to the results, the action for the removal of the surface lignin of non-wood biomass by hydrotropic pretreatment was more significant compared to alkaline and alkaline hydrogen peroxide pretreatments, although a higher total amount of lignin could be removed by alkaline and alkaline hydrogen peroxide pretreatment. Furthermore, xylan could be remarkably more efficiently removed by hydrotropic method. Therefore, the glucan yield achieved from hydrotropic treated sample was higher than that from samples treated with alkaline or alkaline hydrogen peroxide. Through the use of ToF-SIMS, the distribution and localization of lignin and carbohydrates on the surface of ignocelluloses during pretreatment and enzymatic hydrolysis could be detected, and xylan degradation during enzymatic hydrolysis could also be assessed. Thus, based on the results from XPS and ToF-SIMS, the mechanism of the hydrotropic pretreatment in improving the accessibility of enzymes to fibre and further ameliorating of the enzymatic saccharification could be better elucidated.

Comparison of model-based above ground biomass predictions from LiDAR

In order to reduce greenhouse emissions from forest degradation and deforestation the international programme REDD (Reducing Emissions from Deforestation and forest Degradation) was established in 2005 by the United Nations Framework Convention on Climate Change (UNFCCC). This programme is aimed to financially reward to developing countries for any emissions reductions. Under this programm the project of setting up the payment system in Nepal was established. This project is aimed to engage local communities in forest monitoring. The major objective of this thesis is to compare and verify data obtained from di erect sources - remotely sensed data, namely LiDAR and field sample measurements made by two groups of researchers using two regression models - Sparse Bayesian Regression and Bayesian Regression with Orthogonal Variables.

Density and sowing season of two Brachiaria species on the soybean culture

The aim of this study was to evaluate the growth and yield of soybean cultivar M-8766 in consortium with Brachiaria brizantha. BRS Piata and Brachiaria ruziziensis at different densities and sowing dates. The experimental design was randomized blocks with treatments arranged in a factorial 2 x 2 x 3 with four replications. Used as factors grass species (Brachiaria brizantha Piata and Brachiaria ruziziensis BRS) intercropped with soybean M-8766, sowing dates (12 and 24 days after soybean emergence) and three seeding rates (0, 5, 10 kg ha-1 of seed). At 71 days after soybean emergence were evaluated plant height, stem diameter, dry mass of leaves, stems and shoots, and 4 months after sowing determined the weight of 100 grains and soybean yield. The results showed that when seeded at a density of 10 kg ha-1 at 12 and 24 DAE soy, Brachiaria brizantha. BRS Piata caused reduction in yield in the order of 6.71% and 3.03% respectively, while the Brachiaria ruziziensis was one that caused a greater reduction in productivity in the order of 13.42 and 16.23%, respectively, of these values expression when considering the price of soybean sack. B. ruziziensis expressed less competitive with soybean. However, the large biomass production of this grass provides deployment system till the next harvest.

Estimation of weed dry biomass and grain yield as a function of growth and yield traits under allelopathic weed management in maize

Growing concerns about toxicity and development of resistance against synthetic herbicides have demanded looking for alternative weed management approaches. Allelopathy has gained sufficient support and potential for sustainable weed management. Aqueous extracts of six plant species (sunflower, rice, mulberry, maize, brassica and sorghum) in different combinations alone or in mixture with 75% reduced dose of herbicides were evaluated for two consecutive years under field conditions. A weedy check and S-metolachlor with atrazine (pre emergence) and atrazine alone (post emergence) at recommended rates was included for comparison. Weed dynamics, maize growth indices and yield estimation were done by following standard procedures. All aqueous plant extract combinations suppressed weed growth and biomass. Moreover, the suppressive effect was more pronounced when aqueous plant extracts were supplemented with reduced doses of herbicides. Brassica-sunflower-sorghum combination suppressed weeds by 74-80, 78-70, 65-68% during both years of study that was similar with S-metolachlor along half dose of atrazine and full dose of atrazine alone. Crop growth rate and dry matter accumulation attained peak values of 32.68 and 1,502 g m-2 d-1 for brassica-sunflower-sorghum combination at 60 and 75 days after sowing. Curve fitting regression for growth and yield traits predicted strong positive correlation to grain yield and negative correlation to weed dry biomass under allelopathic weed management in maize crop.

MANAGEMENT OF MAIZE STOVER WITH UNDERDOSES RATES OF GLYPHOSATE APPLICATIONS IN NO-TILLAGE

ABSTRACTGlyphosate has significant effects on the growth and development of plants when in underdoses. This work was developed to verify the effect of the application of glyphosate in underdoses in lignin synthesis and consequently decomposition of maize stover. Two experiments were conducted; the first one in a greenhouse for underdoses adjustments and the second one in the production area. The experimental design of the first trial was completely randomized with four replications. The treatments consisted in the application of the underdoses: 0, 25, 50 and 100 g ha-1 of glyphosate. In the production area, the experimental design was a randomized block with four replications, in underdoses: 0, 12.5, 25 and 50 g ha-1. The results were submitted to analysis of variance and regression. The underdoses of 25 g a.e. ha-1in a greenhouse promoted 36% increase in productivity of stover, in addition to increasing the lignin content in 16%, with no change in the unwanted growth of maize plants. In the production area, the concentration of 12.5 g a.e. ha-1 of glyphosate reduced the lignin content and the other underdoses have not changed this feature in maize plants. None of the underdoses affected the height and biomass produced by the maize plants. The highest underdose tested promoted acceleration in the decomposition of maize stover.

Effects of nutrient impoverishment on phytoplankton biomass: a mesocosms experimental approach in a shallow eutrophic reservoir (Garças Pond), São Paulo, southeast Brazil

Nutrient impoverishment in mesocosms was carried out in a shallow eutrophic reservoir aiming to evaluate the nutrient removal technique as a method for eutrophication reduction. Garças Pond is located in the Parque Estadual das Fontes do Ipiranga Biological Reserve situated in the southeast region of the municipality of São Paulo. Three different treatments were designed, each consisting of two enclosures containing 360 liters of water each. Mesocosms were made of polyethylene bags and PVC pipes, and were attached to the lake bottom. Treatment dilutions followed Carlson's trophic state index modified by Toledo and collaborators, constituting the oligotrophic, mesotrophic, and eutrophic treatments. Ten abiotic and 9 biological samplings were carried out simultaneously. Trophic states previously calculated for the treatments were kept unaltered during the entire experiment period, except for the mesotrophic mesocosms in which TP reached oligotrophic concentrations on the 31st day of the experiment. In all three treatments a reduction of DO was observed during the study period. At the same time, NH4+ and free CO2 rose, indicating decomposition within the enclosures. Nutrient impoverishment caused P limitation in all three treatments during most of the experiment period. Reduction of algal density, chlorophyll a, and phaeophytin was observed in all treatments. Competition for nutrients led to changes in phytoplankton composition. Once isolated and diluted, the mesocosms' trophic state did not change. This led to the conclusion that isolation of the allochthonous sources of nutrients is the first step for the recovery of the Garças Pond.

Development of remote monitoring process tools for biomass fired bubbling fluidized bed boilers

Remote monitoring of a power boiler allows the supplying company to make sure that equipment is used as supposed to and gives a good chance for process optimization. This improves co-operation between the supplier and the customer and creates an aura of trust that helps securing future contracts. Remote monitoring is already in use with recovery boilers but the goal is to expand especially to biomass-fired BFB-boilers. To make remote monitoring possible, data has to be measured reliably on site and the link between the power plant and supplying company’s server has to work reliably. Data can be gathered either with the supplier’s sensors or with measurements originally installed in the power plant if the plant in question is not originally built by the supplying company. Main goal in remote monitoring is process optimization and avoiding unnecessary accidents. This can be achieved for instance by following the efficiency curves and fouling in different parts of the process and comparing them to past values. The final amount of calculations depends on the amount of data gathered. Sudden changes in efficiency or fouling require further notice and in such a case it’s important that dialogue toward the power plant in question also works.