A HIGHLY PORTABLE AND INEXPENSIVE FIELD SAMPLING KIT FOR RADIOCARBON ANALYSIS OF CARBON DIOXIDE

Radiocarbon (14C) analysis of carbon dioxide (CO2) can be extremely useful in carbon cycle studies because it provides unique information that can infer the age and source of this greenhouse gas. Cartridges containing the CO2-adsorbing zeolite molecular sieve are small and highly portable, which makes them more suitable for field campaigns in remote locations compared to some other CO2 collection methods. However, sampling with molecular sieve cartridges usually requires additional equipment, such as an infrared gas analyser, which can reduce portability and pose limitations due to power demands. In addition, 14C analysis of CO2 is increasingly being used in field experiments which require high numbers of replicate CO2 collections, placing extra pressure on an expensive and cumbersome collection apparatus. We therefore designed and built a molecular sieve CO2 sampling kit that utilizes a small, low power CO2 sensor. We demonstrate the reliability of the new kit for the collection of CO2 samples for 14C analysis in a series of laboratory and field tests. This inexpensive sampling kit is small, light-weight, highly portable, and has low power demands, making it particularly useful for field campaigns in remote and inaccessible locations.

Determination of the influence of herbicides on dicotyledons plant transpiration using the sap flow method

Physiological parameters are sensitive and provide information on the toxicity of herbicides in plants. The impact of herbicide application on plant transpiration was evaluated by the sap flow method during 2009–2011. The aim of this work was to verify the sap flow method for determining the effect of herbicides on the basis of continuous measurements of the transpiration flow. Helianthus annuus was used as a model plant species. The two different herbicides tested in this study differed by the effect of active ingredients bromoxynil and clopyralid. The water flow was measured using sap flow meter T4.2. The impact of herbicides was assessed by comparing measured transpiration rate (Q) after herbicide application with an extrapolation of transpiration rate of plants before herbicide treatment (Q_calc). After treatment with bromoxynil the Q values decreased significantly compared to Q_calc. For plants treated by clopyralid, the decline of actual transpiration (Q) compared with the modelled one (Q_calc) was less substantial and the plants continued to transpire after the treatment. The effect of herbicides was also verified using infrared gas analyser and chlorophyll fluorescence meter.

Reduction of FeO in EAF Steelmaking Slag by Blends of Metallurgical Coke and Waste Polypropylene

The reduction of FeO-containing slag by blends of metallurgical coke and waste polypropylene (PP) has been investigated through experiments conducted in a laboratory scale horizontal tube furnace. Composite pellets of EAF slag (47.1% FeO) with coke, PP and blends of coke/PP (in three different proportions) were rapidly heated at 1500 °C under high purity argon gas and the off gas was continuously analysed for CO and CO2 using an online infrared gas analyser (IR). The extent of reduction after fifteen minutes, level of carburisation and desulphurization were determined for each carbonaceous reductant. The results show that FeO can be effectively reduced from EAF slag to produce metallic iron using waste PP and its blends with coke as reductants; improvements in the extent of reduction and levels of carburisation and desulphurisation of the reduced metal were observed when coke was blended with PP.

Production of Metallic Iron from Iron Oxide (Fe2O3) Using End-of-Life Rubber Tyre and its Blends with Metallurgical Coke as Reductants

The production of metallic iron from iron oxide using end-of-life tyres (RT) and its blends with metallurgical coke as reductants has been investigated through experiments conducted in a laboratory scale horizontal tube furnace. Composite pellets of iron oxide (96.89 % Fe2O3) with RT, coke and coke/RT blends (in four different proportions) were rapidly heated at 1500 °C under high purity argon gas and the off gas was continuously analysed for CO and CO2 using an online infrared gas analyser (IR). The extent of reduction after ten minutes, level of carburisation of the reduced metal and the total amount of CO2 emissions were determined for each carbonaceous reductant. The results indicate that metallic iron can be effectively produced from Fe2O3 using RT and its blends with coke as reductant. The extent of reduction and level of carburisation are significantly improved when coke is blended with RT. Blending of coke with RT resulted in significant decrease in CO2 emissions.

Fotossíntese, condutância estomática e produtividade de clones de Eucalyptus sob diferentes condições edafoclimáticas

O objetivo deste trabalho foi avaliar a fotossíntese, condutância estomática e produtividade de clones de Eucalyptus em duas áreas distintas: uma no Município de Eunápolis, Sul da Bahia, com precipitação bem distribuída ao longo do ano (área úmida); e outra em Salto da Divisa, Leste de Minas Gerais, com precipitação concentrada nos meses quentes do ano (área seca). Foram estudados quatro clones, avaliando-se o crescimento, através do inventário das árvores; e as variáveis fotossintéticas, medidas com o aparelho Infrared Gas Analyser (IRGA). Dentro de cada área só houve diferença significativa entre clones na área úmida quanto à variável volume de madeira. A produtividade dos clones na área úmida foi 3,3 vezes superior à produtividade da área seca. Na área úmida, todos os clones diminuíram a condutância estomática com o aumento do déficit de pressão de vapor, com queda de 0,16 mol m² s-1 para cada 1 kPa de aumento no DPV e taxa fotossintética máxima variando de 12,5 a 16,4 µmol m² s-1. A comparação entre os clones da área úmida resultou em diferença significativa do clone A, que apresentou fotossíntese máxima superior à dos demais. Na área seca não houve relação entre condutância estomática e DPV e não se observou diferença na fotossíntese entre os clones, que variou de 1,2 a 3,4 µmol m² s-1. Verificou-se relação linear entre a fotossíntese máxima e a produtividade dos clones, evidenciando que a taxa fotossintética foi um dos fatores responsáveis pela maior produtividade do Eucalyptus na área úmida.

Comparison of methods to quantify respirational carbon loss of coarse woody debris

Carbon (C) loss from coarse woody debris (CWD) may be important in forest ecosystem C budgets, yet there are no standard methods of quantifying it. Here we assessed respirational C loss of log segments of European beech ( Fagus sylvatica L.) and Norway spruce ( Picea abies (L.) Karst.), to compare the two main measurement approaches (the static and dynamic methods using soda lime and an infrared gas analyser, IRGA) with three different measurement options for CWD logs. These included (i) incubation of the whole log segment, (ii) the use of small in situ chambers on the curved log surface, and (iii) extracted wedges of wood. On average, significantly higher amounts of CO2 were measured with the IRGA (125%) compared with soda lime. In addition, the soda lime method requires careful calibration of incubation length and amounts of soda lime used. Regardless of the measurement method and tree species, substantially higher amounts of CO2 were measured for whole log segments than for the other two options. Measuring respiration with small in situ chambers on logs or extracted wedges might underestimate real CO2 flux by up to 74%. We therefore recommend measurement of CWD respiration using gas analysers for large log segments.

Sight-specific development of the tools for the measurement of CO2-emission of the soil

Soil is the main source and at the same time the potential sink of greenhouse gases (e.g. CO2, CH4). Measurements were carried out in the experimental sites (soil tillage experiments and an extensive pasture) of the Karcag Research Institute of University of Debrecen, Centre for Agricultural Sciences to determine the CO2-emission of the soil. The in situ CO2-emission of soil was measured by means of an ANAGAS 98 infrared gas analyser in plastic (PVC) chambers, but this previously applied method (cylinders) was not suitable for the soil surface covered with grass,hence a new instrument was needed to be invented. In order to measure CO2-emission on a larger area without deep disturbance of the soil, a special metal frame was created with a matching bowl. The most problematic part was the spatial delimitation of the measurement area as the surface of the soil can be very various and proper isolation is a must. We consider the frame+bowl method we developed suitable for measuring CO2-emission of pastures as well as other crop-fields.