Coal is a chemical compound with a complex composition. Proximate and ultimate analysis as well as physical and mechanical tests which are available do not furnish all the information required by industry. Information regarding e.g. the burning properties of coal is required by furnace and boiler designers. Thermal analysis can be used for studying these properties using small masses of coal. Differential thermal analysis (DTA) where temperature variations are measured which result from reactions which occur when coal is heated and thermogravimetric analysis, (TGA) where similarly mass variations are measured, are regarded as important. Results from eg. TGA tests are usually interpreted without unified and formally accepted prescripts. It is desirable to investigate how the best use can be made of thermal analysis of coal, using DTA and TGA, and to devise a procedure for interpreting the results. The problem is approached by studying DTA and TGA results obtained from a specially selected group of coals for which other analytic data are available. The samples were prepared according to the standard procedure for the laboratory analysis of coal. At first, related information published by other researchers were integrated and parameters used by them identified and assessed in terms of fundamental scientific principles. Special experiments were conducted to probe the situation regarding orthodox kinetics of reactions and its related theory and observed discrepancies with regard to coal and its decomposition characteristics. It was found, along with other observers, that eg. activation energy values which are derived from TGA data should be used with extreme caution. In general an empirical approach for interpretation of results has much to offer. A system is developed by which various thermal techniques, executable by a single instrumental arrangement can be identified by expressing them in matrix format using as indexes, heating arrangement, reactant type and reaction environment. 5(1,1,2) e.g. designates a linearly heated mass of coal in air at atmospheric pressure. To enhance the comparison of TG characteristics of similar coals they should be classified according to a matrix arrangement C(g,t,r) which is based on three index parameters namely, grade ie. the ash content, type ie. the vitrinite content and rank. A TG test provides the basic requirements for computing the indexes using formulae provided by the originators. Information which can only be derived from a TG experiment e.g. 5(1,1,2), are referred to as specification parameters. The information consists of e.g. a series of temperatures which identify specific reaction changes in the coal. Several other parameters can be derived. Coals are assessed by comparing their specification parameters. Only two of the S(i,j,k) techniques are described in detail namely TG dispersion 5(1,1,2) and drop furnace burnout 5(3,1,2). The dispersion technique requires a linear increasing furnace temperature while the near sample temperature is also measured. This technique shows the decomposition stages of coal from dehydration to complete burnout. The drop furnace technique, involves a sudden exposure of the coal to a hot furnace environment with free air access: Actual burnout of coal is emulated. The model is not perfect for combustion but the best that can conveniently be acquired for comparing the burning responses of coals. To illustrate the type of information which can be obtained with other S(i,j,k) techniques experimental results of eg. a devolatilization test are presented. Brief reference is made to the role that particle size plays during combustion and the importance of the composition of volatiles which are released is indicated by presenting relevant information from external sources. The chemical composition and structure of the coals could not be determined but relevant information from an external source was presented which has a bearing on the practical analytic procedure which was described. After a study of the group TG characteristics of the various coals and discussion of the conclusions which are justified a practical procedure is described according to which the equipment can be used both for routine or special purpose analysis of coal. / Thesis (PhD)--University of Pretoria, 2013. / Geology / unrestricted

A madeira desempenha um papel importante na qualidade da cachaça. O armazenamento da cachaça em barris de madeira causa estabilização química e confere características de envelhecimento, provocando alterações nas propriedades sensoriais. O objetivo deste trabalho foi avaliar o uso de quatorze espécies de eucalipto para a confecção de barris destinados ao armazenamento/envelhecimento de cachaça. As espécies utilizadas foram E. citriodora, E. cloeziana, E. maculata, E. microcorys, E. paniculata, E. pellita, E. phaeotricha, E. urophylla, E. pilularis, E. pyrocarpa, E. resinífera, E. saligna, E. tereticornis, E. torelliana. Após a confecção, os barris de 20L foram saturados com água e mantidos a 26°C com pouca luminosidade. A seguir, cada barril foi envasado com a aguardente (46,3°GL) e monitorado mensalmente quanto ao peso. A bebida armazenada por 12 meses foi avaliada mensalmente, por meio de análises físico-químicas e sensoriais com teste de aceitação. Uma amostra da cachaça foi armazenada em recipiente de vidro pelo mesmo período e nas mesmas condições de temperatura. Após doze meses de armazenamento os barris foram desmontados e as madeiras submetidas a análises química e anatômica. A maioria das espécies não apresentou falhas como vazamento ou rachaduras. Características, como pouca permeabilidade a líquidos, puderam ser comprovadas, confirmando as boas condições para se trabalhar com esta madeira na fabricação dos barris. Houve índice baixo de descarte das madeiras em relação à perda de teor alcoólico, com destaque para E. citriodora que apresentou a menor perda, com redução de 2,2%. A espécie E. resinifera foi responsável pela redução de 66% do teor de cobre da bebida. Dentre as amostras analisadas, a cachaça armazenada em barris de E. microcorys apresentou menor taxa de acidez volátil, com 10,12 mg de ácido acético.100mL-1. A amostra armazenada em E. phaeotricha apresentou maior teor de compostos fenólicos totais (CFT), com 88,32 mg.100mL-1. A análise de agrupamento mostrou ser desnecessária a permanência por um ano da bebida em barris de 20L de algumas espécies, com destaque para E. phaeotricha que após 6 meses de armazenamento agregou características superiores às demais.Dentre os congêneres voláteis e de envelhecimento e os parâmetros químicos e físicos das amostras, que as variáveis que mais contribuíram para as características das bebidas foram teor alcoólico, cor, extrato seco, compostos fenólicos totais, ácido vanílico, 5-hidroximetilfurfural, sinapaldeído, coniferaldeído, ácido acético, ácido gálico, 1-propanol, isoamílico, 1-butanol, 2-butanol, isobutanol, acetato de etila e acetaldeído. Em termos anatômicos e químicos da madeira, características físico-químicas e aceitação da bebida, a madeira E. phaeotricha foi superior às demais. As madeiras da espécie Eucalyptus sp possuem boa aptidão para a tanoaria como alternativa para a substituição do carvalho e algumas madeiras nativas na confecção de barris, com destaque para as espécies E. citriodora, E. microcorys, E. phaeotricha, E. pilularis, E. pyrocarpa, E. resinífera, E. saligna, E. tereticornis. No entanto, a escolha dentre as oito espécies supracitadas para a confecção de barris de 20L para armazenar ou envelhecer cachaça por doze meses deve levar em consideração outros fatores como custo do metro cúbico, facilidade de aquisição. / The wood has an important role in the cachaça quality. The cachaça storage in wooden barrels cause chemical stabilization and confers aging characteristics, causing changes in the sensory properties. The objective of this study was to evaluate the use of fourteen species of eucalyptus for the manufacture of casks for storage/cachaça aging. The species tested were E. citriodora, E. cloeziana, E. maculata, E. microcorys, E. paniculata, E. pellita, E. phaeotricha, E. urophylla, E. pilularis, E. pyrocarpa, E. resinífera, E. saligna, E. tereticornis, E. torelliana. After the confection, the casks of 20L were saturated with water and maintained at 26°C in low light. Next, each cask has been filled with cachaça (46,3°GL) and monitored monthly in terms of weight. The beverage stored for 12 months was evaluated monthly, through physical-chemical and sensory analysis with acceptance testing. A sample of the cachaça was stored in glass containers for the same period under the same temperature. After twelve months storage the casks were disassembled and the wood subjected to chemical and anatomical analysis. Most species did not present flaws as leakage or cracks. Characteristics such as low liquid permeability, could be confirmed, confirming the good conditions for working with this wood in the manufacture of the casks. There was a low rate of discard of the woods on the loss of alcohol, especially E. citriodora that showed the smallest losswith a reduction of 2,2%. The species E. resinifera was responsible for 66% reduction of the copper content of the beverage.Among samples analyzed, cachaça stored in casks of E. microcorys showed less volatile acidity rate, with 10,12 mg acetic acid.100mL-1. The sample stored in E. phaeotricha showed higher total phenolic compounds (TPC) content to 88,32 mg.100ml-1. Cluster analysis proved to be unnecessary to stay for a drink year in barrels of 20L of some species, especially E. phaeotricha that after 6 months of storage added characteristics superior to the others. Among the volatile congeners and aging and the chemical and physical parameters of the samples, the variables that contributed most to the drinks of the features were alcohol content, color, dry extract, total phenolic compounds, vanillic acid, 5-hydroxymethylfurfural, sinapaldehyde, coniferaldehyde acetic acid, gallic acid, 1-propanol, isoamyl, 1-butanol, 2-butanol, isobutanol, ethyl acetate and acetaldehyde. In anatomical and chemical wood, physical and chemical characteristics and drink acceptanceterms, wood E. phaeotricha was superior to the others. Eucalyptus sp woods have good aptitude for cooperage as an alternative to the replacement of oak and some native woods, especially the species E. citriodora, E. microcorys, E. phaeotricha, E. pilularis, E. pyrocarpa, E. resinifera, E. saligna and E. tereticornis. However, the choice between the eight aforementioned species for the manufacture of 20L barrels for storing and aging cachaça for twelve months should take into consideration other factors such as cost of a cubic meter, ease of acquisition.

This thesis presents new insights into the chemical composition of semi-volatile compounds in aerosol samples collected in the central Arctic Ocean close to the North Pole in September 2018. The central Arctic Ocean is an inaccessible location due to the lack of land areas along with heavy pack ice conditions. Therefore, large knowledge gaps remain to understand the Arctic climate system, and in particular the role of aerosol particles in its pristine atmosphere. The chemical composition of the aerosol samples was analysed on a molecular level using High Resolution Time-of-Flight Chemical Ionization Mass Spectrometry coupled to a Filter Inlet for Gases and AEROsols (FIGAERO-HRToF-CIMS). The analysis revealed a significant signal from compounds that are likely from marine sources. One important precursor for marine aerosols is dimethyl sulfide (DMS), a gas released by phytoplankton and ice algae in the Arctic Ocean. DMS oxidises in the atmosphere to produce oxidation products that can contribute to aerosol growth. Analysis of air mass origin with backward trajectories showed that the highest ambient DMS concentrations originated from marine areas around the pack ice. However, no correlation could be shown within the pack ice between ambient DMS and its oxidation product methanesulfonic acid (MSA) in the particle phase. As FIGAERO-HRToF-CIMS is commonly used in areas with higher particle concentrations and has never been used in the central Arctic before, this thesis further demonstrates its suitability for measurements of aerosol chemical composition in this remote region. / Denna avhandling ämnar att presentera nya kunskaper om den kemiska sammansättningen av halvflyktiga föreningar i aerosolprover som samlades in i Norra ishavet nära Nordpolen i september 2018. Den innersta delen av Norra ishavet är svårtillgängligt på grund av bristen på fasta landområden ihop med kompakt packis. Därför kvarstår stora kunskapsluckor i förståelsen av klimatsystemet i Arktis, och i synnerhet aerosolpartiklars roll i dess orörda atmosfär. Den kemiska sammansättningen av aerosolproverna analyserades på molekylnivå med högupplöst kemisk joniseringsmasspektrometri kopplad till ett filterinsläpp för gaser och aerosoler (FIGAERO-HRToF-CIMS). Analysen visade på en tydlig signal från föreningar som sannolikt har marina källor. En viktig kemisk föregångare till marina aerosoler är dimetylsulfid (DMS), en gas som frigörs av fytoplankton och isalger i Ishavet. DMS oxiderar i atmosfären till oxidationsprodukter som kan bidra till en storleksökning av aerosoler. Genom analys av provluftens ursprung med trajektorieanalys visades att de högsta DMS-koncentrationerna kom från havsområdena runt packisen. Ingen korrelation kunde emellertid visas inom packisområdet mellan DMS i gasfas och dess oxidationsprodukt metansulfonsyra (MSA) i partikelfas. Eftersom FIGAERO-HRToF-CIMS ofta används i områden med högre partikelkoncentrationer och aldrig har använts i de inre delarna av Arktis tidigare, visar denna avhandling även att tekniken är lämplig för att mäta den kemiska sammansättningen av aerosoler i detta avlägsna polarområde.

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Differences in southern yellow pine (represented by Pinus taeda) and Douglas-fir (Pseudotsuga menziesii) mature and juvenile wood were examined in terms of density, chemical composition, surface energy, shear stress, % wood failure, and delamination. Density was measured using a QTRS density scanner. Loblolly pine contained a higher average density. Chemical composition was measured using the NREL standard for identifying the chemical composition of biomass. Southern yellow pine contained a higher % hemicellulose, lignin, and extractives. Douglas-fir had higher % cellulose than southern yellow pine. Surface energy was measured using the static sessile drop contact angle method and the acid/base approach. Southern yellow pine contained a lower average contact angle than Douglas-fir. Shear stress, % wood failure, and durability were measured using ASTM-D2559 with two adhesives, a one-part moisture cure polyurethane (PU), and a two-part ambient curing phenol-resorcinol-formaldehyde (PRF). Shear stress for southern yellow pine was affected the most by the type of growth regions at the bond (juvenile to mature wood) and the assembly times of the adhesives used. Douglas-fir shear stress was affected by the type of adhesive and the growth region at the bond. Delamination results demonstrated that when using PRF the southern yellow pine has less delamination statistically than Douglas-fir. Also, the growth region at the bond with both adhesives showed to impact delamination with juvenile to mature wood having less delamination than mature to mature wood. / Master of Science

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Tręšimo lauko bandymai buvo atliekami 2007 - 2008 metais, Lietuvos žemės ūkio universiteto Bandymų stotyje. Keturlaukėje sėjomainoje auginami vasariniai rapsai, vasariniai miežiai + įsėlis, daugiametės žolės I n. m., žieminiai kviečiai. Bandymais buvo siekiama įvertinti kalio trąšų formų, jų normų, bei jų derinių su EPSO Microtop įtaką vasarinių miežių derliui. Bandyme buvo auginama lietuviška vasarinių miežių veislė 'Ūla'. Bandyme tirta - kalio chlorido (MOP) bei kalio druskos (Korn-Kali) normų ir papildomo patręšimo per lapus EPSO Microtop (2 x 20 kg ha-1) efektyvumas vasarinių miežių pasėlyje. Bandyme nustatyta, kad kalio ir EPSO Microtop trąšos didino vasarinių miežių 'Ūla' derlių. 2007 metais, lyginant su kontrole, grūdų derlius didėjo nuo 8,8 % iki 18,8 %, o šiaudų derlius - nuo 10,5 % iki 25,5 %. Didžiausi derliai gauti patręšus K90 Korn-Kali norma ir EPSO Microtop (2 x 20 kg ha-1) trąšomis. Šių trąšų normos buvo efektyvios ir 2008 metais, kadangi, lyginant su kontrole, gautas grūdų derliaus priedas 6,8 % - 16,3 %, o šiaudų derliaus priedas -9,5 % -17,6 %. Žaliųjų proteinų kiekis miežių grūduose tręšiant MOP - K90 norma padidėjo 0,56 proc. vnt. Grūdų kokybė buvo geresnė 2008 m., kai grūdų baltymingumas siekė 10,63 %, o 2007 m. 10,40 %. Didžiausias NEM kiekis kontroliniuose laukeliuose - 78,47 %, patręšus tik N60P60 normomis. Didėjant kalio trąšų normai NEM kiekis mažėjo. Tirtos kalio trąšų formos ir normos, bei jų deriniai su EPSO Mikrotop 1000 sėklų masę padidino... [toliau žr. visą tekstą] / Fertilizing field experimentation was done in 2007 and 2008 year at the experimental station of Lithuanian University of Agriculture. Spring rape, spring barley plus under-crop, perennial grass I years of using, winter wheat are grown in four-field rotation of crops. Purpose of the experimentation was to evaluate the influence of potassium fertilizer forms, its norms and it's combinations on spring barley with EPSO Microtop fertilizers. Spring barley breed 'Ūla' was used for the experimentation. Potassium chloride, potassium salt (Korn-Kali) norms and the additional fertilizing through leaves with EPSO Microtop (2 x 20 kg ha-1) the effectiveness of spring barley crop was researched in the experimentation. The experimentation shoved that potassium and EPSO Microtop fertilizers made the yield of spring barley 'Ūla' increase. Grain yield increased from 8,8 % to 18,8 % and straw yield - from 10,5 % to 25,5 % when comparing year 2007 with the control. Best yields were obtained when fertilizing with K90 Korn-Kali norm and EPSO Microtop (2 x 20 kg ha-1) fertilizers. These fertilizer norms were effective in year 2008 also because in comparison with the control the obtained grain yield addition was 6,8 % -16,3 % and straw yield addition - 9,5 % -17,6 %. The crude protein content in grains, after fertilization with MOP - K90 rate increased 10, 37 percent. pc. Grain quality was better in 2008, when grain proteins up to 10.63 % and in 2007 just 10.40 %. NEM controls the maximum number of... [to full text]

Propolis (bičių pikis, bičių klijai) yra sakinga medžiaga, kurią bitės surenka nuo tuopų, beržų, liepų ar kitų augalų (priklausomai nuo tos geografinės zonos augmenijos). Propolio farmakologinis poveikis yra labai įvairus, todėl jis nuo seno populiarus liaudies medicinoje ir traukia mokslininkų dėmesį (ypač nuo XX a. 7 dešimtmečio). Viena iš svarbiausių propolio savybių yra stiprus antioksidacinis aktyvumas. Tyrimo tikslas - nustatyti bei palyginti pagrindinių veikliųjų medžiagų kiekius propolio etanoliniuose ekstraktuose, įvertinti jų antioksidacinį aktyvumą. Pritaikius maceracijos metodą, buvo pagaminti skystieji propolio etanoliniai ekstraktai (etanolis 50%, 60%, 70%, 80% ir 96% koncentracijos). Buvo įvertinta ekstraktų kokybė gravimetriniu, spektrofotometriniu bei efektyviosios skysčių chromatografijos su diodų matricos ir masių spektrometrijos detektoriais (ESCh-DAD-MS) metodais. Pritaikius efektyviosios skysčių chromatografijos ir masių spektrometrijos metodą, nustatyta, kad viena iš dominuojančių fenolinių rūgščių propolio etanoliniuose ekstraktuose yra ferulo rūgštis. Todėl nustatant fenolinių junginių kiekį propolio etanoliniuose ekstraktuose spektrofotometriškai, kaip standartas buvo panaudota ferulo rūgštis. Bendras fenolinių junginių kiekis gautas apie 10 kartų didesnis, nei naudojant pinocembrino ir galangino mišinį (2:1). Daugiausiai fenolinių junginių nustatyta ekstraktuose, gautuose ekstrahuojant 70%, 80% bei 96% etanoliu. Buvo atliktas antioksidacinio... [toliau žr. visą tekstą] / Propolis (bee glue) is a resinous material that honeybees collect from poplar, birch or other plants (the plant source depends on the geographic origin of propolis). Because of its popularity in folk medicine, propolis has become the subject of intense pharmacological and chemical studies for the last 30 years. Numerous studies have proven its versatile pharmacological activities. One of the most important is its antioxidant activity. The objective of this study was to identify and compare the main active substances in the ethanolic extracts of propolis and to evaluate their antioxidant activity. The classical maceration method was used for the production of liquid ethanolic extracts of propolis (the concentration of used ethanol: 50%, 60%, 70%, 80% and 96%). The quality of popolis was evaluated by gravimetric, spectrophotometric and High Performance Liquid Chromatography with Diode Array and Mass Spectrometric detectors (HPLC-DAD-MS) methods. The results of the HPLC-DAD-MS analysis showed that one of the main phenolic acids in the ethanolic extracts of propolis is ferulic acid. That was the reason for using it as a standard in the spectrometric analysis of total phenolic compounds. Spectrophotometric method showed about 10 times higher results than the analysis with the standard of pinocembrin and galangin mixture (2:1). The highest concentrations of phenolic compounds were found in the extracts made with the ethanol of 70%, 80% and 96% concentrations. The antioxidant... [to full text]

Darbo tikslas – ištirti topinambo (Helianthus tuberosus L.) gumbų kokybės kitimą laikymo metu. 2009 metais tyrimams skirti topinambų gumbai išauginti Kauno rajone Babtuose, Lietuvos sodininkystės ir daržininkystės institute. Dviejų selekcinių linijų 05-1 bei 05-7 topinambų gumbai pasodinti gegužės pirmąjį dešimtadienį, nukasti lapkričio mėnesį. Topinambų gumbai po nukasimo 3 savaites laikyti +10oC temperatūros patalpoje žaizdų užgyjimui. Visi mėginiai buvo laikyti 20 savaičių durpėse (4 pakartojimais po 8 kg) šaldymo spintose KX – Ю su automatiniu temperatūros reguliatoriumi, esant 2ºC temperatūrai ir 90 - 95 % santykiniam oro drėgniui. Standartiniais metodais žaliavoje nustatyti sausųjų medžiagų, tirpių sausųjų medžiagų, žalios ląstelienos, žaliųjų proteinų bei amino rūgščių kiekiai. Tyrimų duomenų vidurkiai bei standartiniai nuokrypiai apskaičiuoti „Microsoft Excel“ programa, koreliacinio ryšio analizė – „STAT for EXCEL“ programa (paketas Selekcija, AGROLITPA, 2004. P. Tarakanovas). Nustatyta, kad po 5 mėnesių sausųjų medžiagų kiekis 05-7 selekcinės linijos gumbuose buvo 2,19 % didesnis nei 05-1 selekcinės linijos gumbuose. Po 5 laikymo mėnesių esminiai didesnės tirpių sausųjų medžiagų, žalios ląstelienos kiekių netektys (atitinkamai 1,95 % ir 0,85 %) nustatytos 05-1 selekcinės linijos topinambų gumbuose. Visų tyrimų laikotarpiu daugiausiai abiejų selekcinių linijų laikomuose topinambų gumbuose buvo nustatyta nepakeičiamosios amino rūgšties arginino ir pakeičiamosios... [toliau žr. visą tekstą] / Aim of work – to research the quality changes of Jerusalem artichoke during storageing. In 2009 the Jerusaelem artichoke tubers were grown in Kaunas distric Babtai, Lithuanian institute of gardening and olericulture. Two selection Jerusalem artichoke lines 05-1 and 05-7 were planted in the begining of may and harvested in November. After that they were kept in temperature +10 for 3 weeks in order to treat the slash. The all examples were put in automatically adjusting fridge KX-10 for 20 weeks (8 kg in four replications), where the temperature was 0 – 2 Celsius and the relative humidity 90 – 95 %. The chemical composition was analysed using standart methods: amount of dry matters, melting dry materials, crude proteins, dietary fiber, amino acids. The research data average and standart deviations was calculated using Microsoft Excel program, correlation analyses – „STAT for EXCEL“ program (Selection, Agrolitpa, 2004. P. Tarakanovas). After five months of storage the amount of dry matters in 05-7 selection line tubers was 2,19 % bigger, than in 05-1 selection line tubers. The bigger melting dry materials, diatary fiber losses (accordingly 1,95% and 0,85%) after five months of storage were determine in 05-1 selection line tubers. The biggest amount of inalterable amino acids arginine and glutamine and the smallest amount of alterable amino acids methionine and proline were determine in both of selection line tubers. After five months of storage the quality of 05-7 selection... [to full text]