Search

SynopsisTwo aspects of the relationship between macroalgae and their environment are considered.Firstly, the serious deterioration of algal populations in the Joppa area is examined, comparing recent studies with those of G. W. Traill, an active phycologist working on the marine algae of the Firth of Forth in the nineteenth century.The second aspect of the paper is an assessment of the contribution by macroalgae to estuarine ecosystems. The path of photosynthetically fixed carbon through the growing macroalga, and the various ways it enters the water receive particular attention.

The polished surface technique is used to study the nature and occurrence of opaque matter in coal. The appearance of the opaque matter under reflected light was determined from a polished, thin section, in which the opaque constituents were first established under transmitted light.Two distinctly different forms of opaque matter are recognized, namely, fusain lenses and opaque attritus. Based upon the presence or absence of a botanical structure, the opaque attritus is subdivided into two groups of opaque ingredients. For those devoid of structure the term micrinite is used. Micrinite occurs in three forms: finely divided granular, massive, and as groundmass. Opaque attritus with structure consists of fusinite, semifusinite, and sclerotinite (fungal matter).Evidence for the origin of the opaque matter during the early stages of coal formation is given. A distinction is made between the opaque matter of "primary" origin, and the opacity of high-rank coals, which is due to increased coalification. It is shown that in anthracite the opaque matter of "primary" origin can be recognized under reflected light with the aid of etched, polished sections. No increase in the amount of "primary" opaque matter with increase in rank has been observed.The percentage of opaque matter is determined with an integrating stage, using polished specimens of ground coal, mounted in lucite. The results are compared with the proximate analyses of the coal investigated. They show that a high percentage of opaque matter corresponds with a high percentage of fixed carbon and usually a high percentage of ash.Photomicrographs illustrate the paper.

Siderastrea siderea and Montastrea annularis were labeled in situ with NaH14CO3. The corals were sampled over a period of 11 days and the radioactivity remaining in the ethanolsoluble and ammonia-soluble fractions measured. Total radioactivity in the corals fell to about 1/3 after one night and then to about 1/3 in the next 10 days. The ethanol-soluble radioactivity is probably converted to the less soluble, ammonia-extractable, material in the dark.

A method is described for studying the release of soluble organic material during photosynthesis by benthic algae. The method simulates presumed natural conditions in that the excreted matter is rapidly and continuously removed. This also facilitates analysis of the soluble compounds and the study of factors affecting excretion. Axenic cultures ofPhaeodactylum tricornutum (Bohlin) of good photosynthetic activity, as determined by measurement of oxygen output, were exposed as a surface layer to labelled carbon dioxide in a perspex fixation cell. Deep culture experiments also involved rapid separation of excreted solutes. Levels of excretion of 1 to 3% of total fixation were found. Some of the excreted material had been inside the cell for some hours. The proportion of fixed carbon excreted was similar in old and fresh media and was not affected by the presence of buffer. Co-precipitation with iron and copper was successful in extracting the labelled solutes from the filtrates, but the specific activity was too low to permit complete identification. There appeared to be differences between the materials excreted in surface and in deep culture. A discussion of related studies leads to a suggestion that it may be useful to consider the released solutes as falling into two categories; the first a low but constant level of excretion of more complex compounds, and the second a potentially much higher but variable level of excretion of simpler compounds.

The primary factor causing carbonization of pollen and spores during experimental metamorphism of Waimatua lignite is temperature in excess of 200°C. A secondary factor is the length of time the pollen and spores are subjected to high temperatures. Pressure, however, retards carbonization. Both experimental and field evidence indicate that significant palynomorph carbonization occurs in samples with fixed carbon of 60–65 % and greater.

SummaryRecent published work on the origin of the South Wales coals has shown that the “original deposition theory” is invalid; the pronounced devolatilization of the coals is due to a cause which operated after the formation of all of the seams and the rate of change of the volatiles is governed by a function which can be expressed as an empirical equation. Nevertheless minor variations in coal seam volatiles arising from differences in original composition of vegetation are recognized, and of several examples one is given from the Northumbrian geo-syncline where the highest volatiles are in the lowest Carboniferous Limestone coals and where the extreme variation throughout a sequence of 7,000 feet of coal-bearing strata is 11%. The minor variations lessen progressively if the coal seams become devolatilized. As illustrated by examples from American and European fields, a most important factor in coal seam devolatilization is orogenic pressure with incidental frictional heat.The present basis of comparison of essential coal-substances (fixed carbon and volatiles) is shown to be empirical; a mathematical comparison should be based on the original composition of the coal (not peat) substance. it is shown that 50% fixed carbon and 50% volatiles (d.a.f.) constitute good average figures for the original composition of the coal substance of Carboniferous coals. Loss of weight in devolatilized coals is suffered only by the volatiles so that the best basis of mathematical comparison is the 50% fixed carbon (d.a.f.). The volatile percentages of the South Wales seams when calculated on this basis all show a pronounced drop in values, and on the 50% fixed carbon basis it is necessary to find a new controlling function for the rate of change of volatiles in coal seams lying in vertical sequence. It is found that this is best expressed by the following exponential equation:where v2 and v1 represent the volatiles of the lower and upper seams respectively, y is the vertical distance in feet of v2 below v1; and θ is the angle of dip of the zero plane previously determined in South Wales as 5°.

Whole young plants were allowed to fix photosynthetically C14O2 for 12 hours. The absolute amount and the specific activity of trigonelline, caffeine and glucose in developing and adult leaves were subsequently determined during up to five weeks. There is a rapid incorporation of photosynthetically fixed carbon into trigonelline in both developing and adult leaves. The specific activity of caffeine however increases to any extent only in young developing leaves. It can be concluded that both trigonelline and caffeine are synthesized in leaves ofCoffea arabica. Other problems of the metabolism and translocation of the two substances are discussed.

Samples of charcoal recovered from excavated sites were treated with strong acid, followed by strong base. This process removes most of the inorganic carbonates and organic compounds, leaving highly condensed or elementary carbon. The fixed carbon content of the specimens from four sites varied widely and indicated different sources of organic matter. Each charcoal, therefore, has a characteristic chemical composition. CHARCOAL and carbonized organic matter have long been of interest to archaeologists as a diagnostic tool for detecting human occupation and for evaluating the culture concerned, particularly with respect to the source of burned material. A classical instance is that described by Black (1931), in which he analyzed charred bones and concluded that Sinanthropus knew the use of fire. He extracted soluble salts with hydrochloric and nitric acids and then removed the black residue completely with chromesulphuric acid, thus demonstrating that it consisted of carbon rather than of metallic oxides. More recently Oakley (1954) analyzed ash deposits found at the Cave of Hearths at the Makapan sites, central Transvaal, and differentiated the basal level from the overlying strata by means of the percentage of free carbon present. He does not state, however, how the value of free car

Summary The 14 C incorporation from 14 CO 2 into photosynthesis products in either normal (21 %) or high (approximately 100%) O 2 concentration was investigated. In 100% O 2 assimilation of 14 CO 2 was inhibited by about 50%. It was associated with a decrease of 14 C in PGA, alanine and sugars but with an increase of radioactivity in glycine and serine. In pulse-chase experiments 14 C moved from all the earlier labeled compounds into sugars with only small effect of oxygen. The radioactivities incorporated into sugars were in both O 2 concentration nearly equal when the total amounts of assimilated 14 CO 2 per 1 g of fr. wt. of needles were similar (as the result of higher 14 CO 2 concentration in 100% O 2 ). In that case, however, incorporation of 14 C into glycine and serine in 100% 02 was always about 3 times higher than in normal O 2 concentration. The inhibition of total fixation of 14 CO 2 by isonicotinyl hydrazide was much higher in 100% than in 21 % oxygen. The results suggest that in high O 2 concentration compared to 21 % O 2 , larger part of photosynthetically fixed carbon passes into sugars through intermediates of glycolate pathway.

Summary The variation of volatile contents in seams in a horizontal sense is shown on an isovol map constructed by the Fuel Research Board following on a coal survey of the South Wales Coalfield. Nine vertical sequences of seams were also assembled, giving the volatile contents of each seam and its depth below a top seam assumed as a datum. For each of these sequences the constants and coefficients in each of four hypothetical relations were found by the least-squares method; these four hypotheses are: Hilt9s law, the square-root relationship proposed by F. M. Trotter, the exponential relation suggested by H. W. Wellman between the ratio of the volatiles to fixed carbon and the depth, and another exponential relation between the volatiles and the depth. When applied to calculate the volatile contents of the other seams in the sequences all these relations gave results which did not differ significantly. The sequences cannot therefore give a verdict in favour of or against any one of the above hypotheses. The fact of greatest interest that emerged is that the coefficients for each expression vary so widely from one part of the field to another that no expression which uses a fixed value for its coefficient can be applied successfully to the coalfield as a whole. A surprising empirical relation was found, however, between these varying values and the mean volatile contents over which they hold, and from this expressions were derived which enable the volatile contents of any seam to be calculated or predicted if its depth below any other seam of known volatile content is given. These calculations are independent of any theory and the same value is obtained whichever of the above expressions is used if its coefficient and constant are determined by standard methods. The intimate relation between volatile contents and depth has been used to construct a contour map showing the depth of the Nine Feet Seam below an assumed datum of a seam with a 40 per cent volatile content. It is considered that this extremely intimate relation between volatile content and depth can be explained only by the hypothesis that the changing conditions which obtained when the seam was buried to varying depths are responsible for the variation of volatile contents. These relations are applied to certain problematic areas in the coalfield.

Two simplifying hypotheses have been proposed for whole-plant respiration. One links respiration to photosynthesis; the other to biomass. Using a first-principles carbon balance model with a prescribed live woody biomass turnover, applied at a forest research site where multidecadal measurements are available for comparison, we show that if turnover is fast the accumulation of respiring biomass is low and respiration depends primarily on photosynthesis; while if turnover is slow the accumulation of respiring biomass is high and respiration depends primarily on biomass. But the first scenario is inconsistent with evidence for substantial carryover of fixed carbon between years, while the second implies far too great an increase in respiration during stand development – leading to depleted carbohydrate reserves and an unrealistically high mortality risk. These two mutually incompatible hypotheses are thus both incorrect. Respiration isnotlinearly related either to photosynthesis or to biomass, but it is more strongly controlled by recent photosynthates (and reserve availability) than by total biomass.

The purpose of the research is to develop and test the characteristics of durian's peels briquette as fuel material. It was tested by applying proximate analysis and was conducted in Laboratories. The researcher carbonized it at temperature 200-500 oC for 1.5 hours. From the process of proximate analysis on 450oC carbonization temperature could be found that there is 77.87% Fixed Carbon (FC), 0.01% Moisture (M), 3.94% of Volatile Matter (VM) and 18.18% Ash (A). The chemical properties of briquettes gained 0.09% of moisture content, 0.99 g/ml of density, 6,274.29 kcal/kg of calorific value, the size of 100 mesh of briquettes composer particle have compressive strength at 15.10 N/cm2 apply on 3.8 cm of diameter briquette in high at 6.5 cm.

O carvão vegetal é um produto de grande importância na economia brasileira, fato este ligado ao seu uso como fonte de energia renovável e redutor no setor siderúrgico. Esforços vêm sendo feitos visando à melhoria do processo de produção do carvão vegetal, o qual pode ser obtido em diferentes tipos de fornos, com rendimentos e qualidade variados. Dessa forma, o objetivo deste trabalho foi realizar o levantamento das características referentes à planta de carbonização pertencente à Saint Gobain Ltda. situada no município de Seropédica/RJ e analisar quimicamente o carvão produzido. Os dados foram obtidos por meio de questionário e comparados aos de outras duas empresas do mesmo segmento. A análise das amostras de carvão vegetal foi realizada em laboratório, através da análise química imediata. Os fornos utilizados na produção de carvão vegetal existentes na planta de carbonização da empresa analisada caracterizam-se como fornos de superfície com chaminé. O rendimento médio observado da conversão da madeira em carvão vegetal foi de 50%. Na comparação com outros sistemas de carbonização, a empresa analisada apresentou valores intermediários em termos de rendimento do processo e o carvão vegetal produzido foi considerado de boa qualidade, apresentando elevado teor de carbono fixo (82,70%) e baixo teor de cinza (1,30%). ABSTRACT Charcoal is a product of great importance in the Brazilian economy, a fact linked to its use as a renewable energy source and reducing the steel industry. Efforts have been made aiming at improving the production process of charcoal, which can be obtained in different furnace types with varying yield and quality. Taking these factors into consideration, the aim of this study was to survey the characteristics relating to the carbonization plant belonging to the Saint Gobain Ltda. company, in the city of Seropédica/Rio de Janeiro-Brazil and chemically analyze the coal produced. The data were obtained through a questionnaire and compared to the other two companies in the same industrial segment. The analysis of charcoal samples was conducted in the laboratory through chemical analysis. The furnaces used in charcoal production in existing carbonization plant analyzed company are characterized as surface furnaces with chimney. The average output of the conversion of wood charcoal was 50%. Compared to other carbonization systems, the company analyzed showed intermediate values in terms of process yield and charcoal produced is considered good quality, with high fixed carbon content (82.70%) and low ash content (1,30%).

La2O3 is a combustion improver suitable for burning pulverized coal in blast furnace. La2O3 forms the active species La3+(CO−)3 that weakens the bridge adhesion of carbon structural units and alters the lattice structures, thus reducing the activation energy of the pulverized coal and accelerating the burning process. Research shows that La2O3 can form the active species La3+(CO−)3, which weakens the bridge adhesion of carbon structural units and alters the lattice structures of the fixed carbon, hence decreasing the activation energy of the pulverized coal and accelerating the burning process.

This study aimed to evaluate the Eucalyptus grandis and Eucalyptus saligna, from production areas of Rio de Janeiro State, intended for energy use. The selection consisted of six trees per specie, at six years old. The wood samples had its basic density determined, then, was subjected to the pyrolysis process with 500 °C of final temperature. Charcoal, pyroligneous liquid and non-condensable gases yields were determined. In addition, the charcoal had its immediate analysis performed to determine the levels of volatiles matter, fixed carbon and ash content. Data were analyzed using descriptive statistics, Pearson correlation and principal component analysis. The correlation analysis and principal component analysis were effective to predict recommended species. Based on the results, the most recommended specie for energy purposes was the Eucalyptus grandis. RESUMO O presente estudo teve por objetivo analisar a madeira de Eucalyptus grandis e Eucalyptus saligna oriunda de áreas de produção do Estado do Rio de Janeiro com vistas ao uso energético. Selecionaram-se seis árvores por espécie, com seis anos de idade. Determinou-se a densidade básica da madeira e, em seguida, amostras de madeira foram submetidas ao processo de pirólise com temperatura final de 500 °C. Foram determinados os rendimentos em carvão vegetal, em líquido pirolenhoso e em gases não condensáveis. Foi realizada a análise imediata do carvão, para a determinação dos teores de materiais voláteis, cinza e carbono fixo. Os dados obtidos foram analisados por meio da estatística descritiva, correlação de Pearson e análise de componentes principais. A análise de correlação e a análise de componentes principais foram eficientes na predição da espécie recomendada. Com base nos resultados, a espécie mais recomendada para fins energéticos foi o Eucalyptus grandis.

Assimilation of carbon-14 labeled bicarbonate into photosynthetic products was measured at four stations in the Southern Ocean. Phytoplankton populations incorporated as much as 80 percent of the fixed carbon into lipid under conditions of low temperatures (-0.2 degrees to -1.8 degrees C) and low light intensities. At higher temperatures (+0.3 degrees to +0.8 degrees C) and higher light intensities, incorporation into lipid accounted for less than 20 percent of the fixed carbon, synthesis of polysaccharide and protein being more prominent.

Burning profiles and SO2-formation profiles were measured simultaneously for four different coals by slowly heating coal samples in a flow of air in a thermobalance. The profiles of weight loss and SO2 formation have the same shape with anthracite combustion. The SO2-formation profiles of bituminous coals usually display two peaks that approximately correspond to the release of volatile matter and combustion of char in the burning profiles. No correlations could be found between either the types of sulphur present in the raw coals or the ratio of volatile matter to fixed carbon and the shape of the SO2-formation profiles for the bituminous coals.

The use of solid-state 13C cross-polarization n.m.r. for rapid analysis of bore cores is demonstrated by examination of subsections of a Glen Davis oil shale bore. The determined aromaticities, fa, differ widely between subsections indicating large variability in potential oil yields. The variation does not correlate with depth of subsection but is shown to correlate well with maceral composition. The correlation found previously by Zilm and co-workers (Fuel 1981, 60, 717) between fa, determined by solid-state 13C n.m.r., and wt% fixed carbon for a range of macerals is found to be supported by the data for Glen Davis subsections which are mixtures of all three maceral types.

Nine South Wales coals of different rank and composition and seven structurally disturbed outburst prone coal samples were studied using electron paramagnetic resonance. An increase in baseline spin concentration with fixed carbon content was observed across the South Wales coalfield. Enhanced spin concentrations were observed for the structurally disturbed outburst prone coal samples. The g value remained more or less constant with varying structural condition, fixed carbon, and volatile matter content of the coal.

In a boring made for water some months ago at Heathfield Railway-station (L. B. & S. C. R.) an outflow of natural gas was encountered. A cap provided with a cock was placed at the outlet of the boring, and thus the collection of a sample of the gas for analysis was an easy matter. Owing to the courtesy of Mr. R. J. Billinton, the Locomotive Engineer of the London, Brighton, & South Coast Railway, who not only gave me the necessary permission, but also placed every facility at my disposal, I was enabled to take a sample of the gas on Dec. 31st, 1897. Mr. Billinton further informed me that a bed of lignite had been encountered at a depth of about 300 feet; this was of considerable thickness, and was supposed to be the stratum in which the gas had its origin. He very kindly provided me with a specimen of this substance, which one can perhaps better regard as a shale; this also was analysed. The gas was examined for oxygen, carbon dioxide, carbon monoxide, olefines, and hydrocarbon vapours ; these were found to be absent. Analysis of the Shale. In the first place the shale was analysed according to the customary method of carrying out commercial analyses for coal. The following result was obtained:— It should be pointed out thai, very little reliance can be placed on the numbers for volatile matter and fixed carbon, as, owing to the large amount and porous nature of the

Summary One case is presented of a 66 year old stove molder who had worked 48 years in a foundry exposed to the inhalation of silica, iron oxide, and fixed carbon. A very extensive pneumonokoniosis ensued, and secondary to this, he developed a bilateral pulmonary abscess from which he died 28 days later. The autopsy report is included.

In the annual succulent Mesembryanthemum crystallinum growing in situ, the balance between C3 and CAM carbon fixation shifted rapidly in response to changes in water availability. When water was plentiful, M. crystallinum fixed carbon dioxide by the C3 pathway and grew at rates comparable to other C3 species. Under drought conditions, M. crystallinum fixed carbon by the CAM pathway at an average rate which exceeded 1 nanomole of carbon dioxide per square centimeter of leaf surface per second, a very high rate for a CAM plant.

Whereas elementary processes of carbon photoassimilation, sucrose synthesis, phloem loading and unloading, have been well described, little information is available regarding protein synthesis from photosynthates in leaf and kernel during grain filling. To gain a better understanding of the biochemical basis for partitioning of photosynthetically fixed carbon between leaf and grain a 14CO2 labelling study was conducted with field-grown plants 30 days after flowering. Carbon flow was followed by separation and identifixation of 14C assimilates and 14C storage molecules within each tissue.

During the first 3 days ofdevelopment of the rabbit embryo, carbon fixed from CO2 accumulated in the embryos and culture medium and increased as development proceeded. Ultracellularly, incorporation of carbon into acid-soluble material accounted for 60 to 85% of the total fixed carbon, with most of the the remaining carbon entering the protein fraction. In the medium, most of the fixed carbon was found in the acid-soluble fraction. Although

Pithiness is the autolysis of stem and petiolar pith resulting in a hollow organ. It can be caused by genetic programming or environ­mental stresses. It is mediated by the absence of ethylene production, such that treatments which induce moderate amounts of ethylene evolution, protect the plant against pithiness. Since pithiness results from the need to maintain optimum growth in the face of insufficient fixed carbon, ethylene inhibits the development of pithiness by retarding growth.

In today’s fast-changing world with its great need for renewable energy sources, it is essential that the prospective charcoal-maker be aware of the limits and opportunities of the technology and the choice of equipment available to him. An important criterion will always be the achievable energy yield from the raw materials under consideration. Yield comparisons are difficult to establish; a great deal of experience is necessary, and tests must be performed on firm parameters. These are, among others, dry material weight, fixed carbon content and calorific value of the char, and a defined energy value of the liquid and gaseous by-products, if any.

Individual lignite bodies have been mapped using over 2,700 water-well records, more than 100 electric logs, literature references, and unpublished well bores of the Forest Service. Petrographic, proximate, ultimate, and fusibility analyses have been determined. The lignite occurs as scattered pods with overburden ranging from 25 to 200 ft (7 to 60 m). All of the lignite is of Tertiary age. Most of it is in the undifferentiated Wilcox Group and the rest is in the Midway Group. The lignite bodies vary widely in their properties, but most are low grade. The average heat content is 7,849 BTU (8,280,695 J), but individual samples cover the entire range of heat values for lignite. The volatile content and ash content tend to be high. Sulfur averages 0.82% but ranges up to 3%. The fixed carbon content is low. In thin section, the samples appear to be typical lignites. Most of the lignite pods contain less than 3 million tons in place, but three deposits range between 25 million and 50 million tons in place. End_of_Article - Last_Page 516

The principal tenets of the carbon-ratio theory are (1) that the chief agencies in the chemical transformation of carbonaceous deposits, after they have passed through the biochemical stage, are the pressure and the heat derived from horizontal thrust; (2) that as the coals decrease in volatile constituents the oils show a corresponding increase in the lighter and more volatile hydrocarbons, so that low-grade oils are associated with low-rank coals and high-grade oils with high-rank coals; and (3) that where the coals have reached the stage of devolatilization at which their content of fixed carbon constitutes about 65 per cent of their total combustible matter the oils in the coal-bearing and underlying formations have been converted into gases, and where the state of de olatilization is slightly higher the gases have been eliminated. Inasmuch as a series of coals increases in percentage of fixed carbon with stratigraphic depth in both disturbed and undisturbed areas, and this increase is many times greater than any recorded increase in the horizontal direction, the writer is led to conclude (1) that the geologic agencies producing the chemical transformation of carbonaceous deposits are not so much the heat and pressure incident to horizontal thrust as the heat and pressure incident to depth of burial; and (2) that there is no clear evidence that incipient alteration of sediments has been a factor in determining the extent of our known oil and gas fields and therefore that carbon ratios of coals furnish no information as to the oil possibilities of an area.

The incorporation of fixed carbon from carbon dioxide into mouse embryos was greatest in eight-cell embryos which developed into blastocysts during a 24-hr culture period and was four to five times greater than the incorporation into two-cell embryos cultured for a similar period. The net accumulation of labelled products in the culture medium was greatest during the culture of the morula stage to the blastocyst over 24 hr.

The essence of the carbon-ratio theory is the assumption of a causal connection between stages of metamorphism and the occurrences of gas and oil. Many geologists are of the opinion that the observations of White, Fuller, Russell, Moulton, and other investigators constitute proof of a causal assumption in pointing out that there is a definite relationship between degrees of alteration, using the fixed carbon of coal as a pyrometer, and oil and gas occurrences. Other geologists, although not questioning the observational data indicating the relationship, are led by the serious inconsistencies in the application of the theory, in so far as its causal feature is concerned, to believe no causal connection has been proved. The chief inconsistencies are: (1) the problem of resi ues, (2) the occurrences of oil of lower grade in older beds below higher-grade oil in younger beds, and (3) the presence of areas producing only dry gas in quantity in the same zone of alteration with areas producing oil, and oil and gas. The writer seeks in this discussion to compare the evidence regarded as proof of the theory with these inconsistencies. The conclusion is reached that, so far as the causal part of the theory is concerned, it has the same status it had when the theory was first enunciated--an unproved assumption.

(1956). A Simple Electrometric Technique for the Determination of Carbon Dioxide Tension in Blood and Plasma, Total Content of Carbon Dioxide in Plasma, and Bicarbonate Content in “Separated” Plasma at a Fixed Carbon Dioxide Tension (40 mm Hg) Scandinavian Journal of Clinical and Laboratory Investigation: Vol. 8, No. 1, pp. 33-43.

Responding to the comments and criticism offered since the publication of his paper, "Some Relations in Origin Between Coal and Petroleum," embodying the so-called "carbon-ratio theory," published 20 years ago, the author discusses the progressive regional metamorphism of the mother rocks of coal and oil, which advances from stage to stage with each advance in orogenic movement, the periods of advance being, he holds, those of most active oil generation and of metamorphism represented by cracking, with probable underground enrichment or hydrogenation of oil in confinement. The extinction zone, or the oil "dead line," at which in their evolution the oils have become so light that they are no longer liquid at surface temperature and atmospheric pressure, is found in many re ions to fall in a zone narrower than at first defined and represents a carbonization (indicated by fixed carbon, pure coal basis) between 61 and 63 of the associated coals in those regions. Oil is believed to have been generated in several cycles, in all cases probably under dynamic influence. Relations of regional metamorphism to the "law of Hilt," which applies to oils as well as to coal, are discussed, together with sources of error, in defining the extinction zone.

Photosynthetic carbon assimilation by isolated chloroplasts and its associated oxygen evolution were measured simultaneously in a single simplified reaction mixture. Each showed an initial lag prior to the attainment of the maximal rate and the photosynthetic quotient was unity during the period of illumination. Following illumination an oxygen uptake was observed in the dark which was not accompanied by any net release of newly fixed carbon dioxide.

There is considerable variation among species in their rate of photorespiration, and photorespiration increases greatly at higher temperatures. The addition of an inhibitor of glycolate oxidase, alpha-hydroxy-2-pyridinemethanesulfonic acid, to tobacco leaf disks at 35 degrees stimulated photosynthetic (14)CO(2) uptake at least 3-fold, but (14)CO(2) uptake was not changed by the inhibitor at 25 degrees . The inhibitor did not increase photosynthesis in maize leaf disks at either temperature.The evolution of CO(2) from glycolate was greatly enhanced in tobacco at 35 degrees compared with 25 degrees . Labeling of the glycolate of tobacco with glycolate-1-(14)C and -2-(14)C showed that the increased CO(2) evolved in the light (photorespiration) arose specifically from the carboxyl-carbon atom of glycolate. Maize, a species known to have a negligible photorespiration, produced (14)CO(2) poorly from glycolate-1-(14)C in comparison to tobacco.Acetate-1-(14)C, a substrate metabolized by dark respiration, produced similar amounts of (14)CO(2) in the light in both tobacco and maize. This respiration was changed little relative to photosynthesis by increasing temperature.Most plants, such as tobacco, have a high photorespiration. The loss of fixed carbon causes an increase in the internal concentration of CO(2) especially at higher temperatures, and results in a lower CO(2) concentration gradient and therefore a lower net photosynthetic CO(2) uptake. Some species, like maize, have a negligible photorespiration and are thus more efficient photosynthetically. The use of an inhibitor of the oxidation of glycolate, the substrate for photorespiration, changed tobacco so that it behaved photosynthetically like maize. Thus high rates of photorespiration may limit the net CO(2) uptake in many plant species.

THE explosive increase in the world's population has been accompanied by an overall food shortage. New and increased supplies of food, especially high quality protein, are urgently needed. Earlier investigations have described the growth of micro-organisms on paraffins, synthetic liquid fuel (‘Kogasin’), and petroleum fractions1–3. Recently, it has been found that micro-organisms convert petroleum or petroleum fractions to protein, vitamins, or amino-acids4–14. Because coal is a cheap fossil fuel and by far the most abundant source of readily available, fixed carbon, investigations were initiated to determine whether coal could serve as a source of high protein food.

EnglishThe use of wood for energy purposes is common in Brazil, motivated mainly by the diversity of species that present a potential for energy production. The objective of this study was to determine the effects of tree age and spacing on the energy properties of different components of the biomass: wood, bark, and branch of the species Ateleia glazioviana Baill, distributed at different spacings: 2.0 × 1.0m, 2.0 × 1.5m, 3.0 × 1.0m, and 3.0 × 1.5m in the 1st, 3rd, and 5th year after the planting. The experiment was carried out in a randomized complete block design with three replications. The following variables were determined: biomass (BIO), gross calorific power (GCV), basic density (BD), energy productivity (EP), energy density (ED), fixed carbon content (FCC), volatile material content (VMC), and ash content (AC). Different tree ages significantly affected all analyzed variables, increasing the distribution of BIO, EP, AC, BD, and ED with no tendency to stabilize over time. The four tree spacings induced different levels of BIO and EP, with a trend toward lower values with increasing tree spacing for all assessed periods. The four components of the trees had a significant effect on the variables BIO, EP, GCV, FCC, VMC, and AC. Key words: Timbo; biomass; gross calorific power; energy productivity portuguesA utilizacao da madeira para fins energeticos e elevada no pais, motivada principalmente pela diversidade de especies que apresentam potencialidade de geracao de energia. Esse trabalho teve como objetivo determinar o efeito da idade e do espacamento de plantio nas propriedades energeticas em diferentes compartimentos da biomassa: madeira, casca e galho da especie Ateleia glazioviana Baill, distribuida em diferentes espacamentos: 2,0x1,0m, 2,0x1,5m, 3,0x1,0m e 3,0x1,5m, no 1o, 3o e 5o ano apos o plantio. O presente trabalho foi realizado em um experimento instalado em delineamento experimental de blocos completos casualizados em tres repeticoes. Foram determinadas as variaveis biomassa (BIO), poder calorifico superior (PCS), massa especifica basica (ME), produtividade energetica (PE), densidade energetica (DE), teor de carbono fixo (CF), teor de material volatil (MV) e teor de cinzas (CZ). Concluiu-se que as diferentes idades das arvores influenciam significativamente todas as variaveis analisadas, proporcionando uma distribuicao crescente da BIO, PE, CF, ME e DE, sem tendencia a estabilizacao ao longo do tempo. Os quatro espacamentos de plantio induzem a diferentes producoes de BIO e PE, com uma tendencia de reducao dos seus valores com o aumento do espacamento, em todos os periodos avaliados. Os quatro compartimentos das arvores induzem a um efeito significativo das variaveis BIO, PE, PCS, CF, MV e CZ. Palavras-chave: timbo; biomassa; poder calorifico superior; produtividade energetica

This work aimed to chemically and energetically characterize palm waste in the municipality of Igarapé Açú-PA. The residue was crushed, sieved and acclimated up to 12% of humidity. Chemical analyses were performed in the fresh material, according to NBR standards. Part of the residue was transformed into charcoal at 450 °C, with heating rate of 1.67 °C.min-1 and residence time of 30 minutes. Elementary analysis (CHNS-O) was carried out in the fresh and carbonized material. For biomass, means of 32.67% of lignin and 2.58% of minerals were found. Means of 79.71% for volatile materials and 9.85% for fixed carbon were also found. In the elementary analysis, mean values of 53.79% for carbon and 0.7% for sulfur were found. Palm biomass residues presented high fixed carbon, structural carbon and lignin levels, thus presenting potential to be used in the direct production of energy, activated carbon and also biochar.

Carbon pricing is a cost-effective method for mitigating climate impacts. This article examines the conventional life cycle cost (LCC), net present value (NPV), and carbon dioxide (CO2) emissions of the Solid Oxide Fuel Cell Electric Vehicle (SOFCEV) powered by Brazilian fuels. The cost reduction potential of the SOFCEV was evaluated, considering the Brazilian productivity of sugarcane and the carbon fixed by these plantations, through the mechanism of carbon credits sale. Sugarcane ethanol and gasoline C (73% gasoline A and 27% anhydrous ethanol) were considered. Three scenarios were outlined: a) Cost of investment, fuel production, and vehicle maintenance and operation in USD/km, over a 10-year amortization period; b) SOFCEV emission cost from well-to-wheel added to cost (a); c) Cost of carbon fixed by hectares of sugarcane in Brazil necessary to supply the fuel demand of the SOFCEV subtracted from (b). Results showed that the ethanol-fuelled SOFCEV attends the carbon-neutral cycle, since the carbon credit sale resulted in an avoided cost 1.1 times higher than the emissions cost. Gasoline C showed similar results for the three scenarios, with an emission cost 2.5 times higher than the avoided cost. Carbon pricing was not sufficient to make the technology more viable for consumer, with an expected NPV of -USD 8006.38 after the amortization period. Thus, it is expected to obtain economic indicators to encourage the use of biofuels in electric fleets.

6 pages, 2 figures, Invisible to the naked eye, yet dominating life with some 10 cells, bacteria and archaea (referred to herein as ‘microbes’) play key roles in the global cycling of nutrients, matter and energy in our oceans. Having experimented for over 3.5 billion years since their first appearance, they are true master chemists that are capable of carrying out the most diverse and complex of chemical reactions. One of the most abundant groups, cyanobacteria, converts light into chemical energy by fixing carbon dioxide into organic matter. Part of this fixed carbon is consumed by higher trophic levels, while another fraction sinks to the deep sediments where, over geological time scales, it fossilizes into the natural resources that we tap into for our everyday lives. Despite our knowledge of their global importance and significant recent advances in marine microbiome research (Figure 1), some of the most fundamental questions still remain unanswered, and serve as active drivers of current research in this field: How many microbes are out there, and how many different types? What are they? What are their functional roles? How are they globally distributed? How do they adapt to varying environmental conditions and how will they respond to future environmental changes? This Primer provides a brief overview on how these questions have been addressed in the context of developing technologies. We discuss new insights, as well as new concepts and more refined questions, and we highlight some of the future promises and challenges that lie ahead

Char reactivity is generally higher the (a) lower the rank of the precursor coal’3*, (b) lower the temperature to which the char has been taken prior to reaction133, (c) shorter the soak time at maximum heat treatment temperature (HTT)3, and (d) smaller the char particle size’, We have now found another variable which can affect subsequent char reactivity, that is the heating rate to maximum HTT. Chars were produced from a 70 x 100 U.S. mesh North Dakota lignite having the following ASTM analysis: ash (dry), 7.3%; VM (daf), 47.1%; and fixed carbon (daf), 52.%. Chars were prepared by heating the lignite in nitrogen to maximum temperature either in a fluidized bed at 10” C/min or in a laminar-flow unit at about 8 x 103”C/s 4. In both cases, soak time at maximum temperature was under 1 s. Subsequently, char reactivity in 0.1 MPa of air was measured at 500°C in a TGA apparatus as previously described’. The char sample was heated in the TGA unit at lO”C/min to 500°C in N2 and soaked for 15 min prior to studying reactivity. Reactivity was expressed as

Nine Canadian coals of different rank and composition were studied by electron spin resonance. For percentage of fixed carbon in the range of 43 to 78 wt%, the free radical g values were found to increase with decreasing carbon content, and did not level off for the low rank coals. The free radical linewidths are attributed to atomic species such as oxygen and not to protons of hydrogen.

Some of the sources of error in measuring the excretion rate of phytoplankton are discussed. Among those factors are: damage to cells during handling, contaminant C/sub 14/, errors resulting from aliquoting, variable storage times, and incubation time. These sources of error are discussed in regard to a previous paper which had argued that the release of fixed carbon was substantial. The conclusion reached is that indeed, the release (excretion) of organic material by phytoplankton is of substantial magnitude. 10 references.

WHILE examing the beneficiation of fine coal from the Bulli seam, New South Wales, by froth flotation, the hydrophobic characteristics of the coal were observed. Air-borne dust from this seam had an average composition of fixed carbon 60 per cent, volatiles 26 per cent, ashforming constituents 12.5 per cent and moisture 1.5 per cent. This dust contained a high proportion of vitrain.

CALVIN and his co-workers1 have suggested that 6,8-thioctic acid, the prosthetic group of pyruvic oxidase, is a key substance in photosynthesis, since the oxidized and reduced forms of this compound may control the distribution of the fixed carbon into the ‘true’ products of photosynthesis (for example, sugars) and the Krebs-cycle acids. It was proposed that thioctic acid is closely associated with the primary photochemical process2, and experimental evidence was advanced in support of the contention that thioctic acid increases the quantum efficiency of the Hill reaction in Scenedesmus3,4. This communication summarizes the results obtained in an investigation on whether the photosynthetic reduction of carbon dioxide also is stimulated by thioctic acid.

K-Ar and Rb-Sr measurements on whole rocks and on separated size fractions of Pennsylvanian underclays were made in an attempt to relate the apparent ages to the degree of metamorphism, by analogy with the fixed carbon content of the associated coals. Five whole-rock samples (fixed-carbon contents ranging from 50 to 90 percent) give fairly uniform K-Ar ages between 355 and 383 m.y. The apparent ages of two samples deviate significantly from the average with values of 416 m.y. (fixed carbon, 75 percent) and 327 m.y. (fixed carbon, 95 percent). No systematic relation between coal rank and whole-rock K-Ar age is apparent. Individual size fractions of two samples show nearly concordant but systematically decreasing K-Ar and Rb-Sr model ages (510 to 320 m.y.) with decreasing grain size. This effect cannot be explained by any simple volume diffusion model; it is most likely due to crystallization or reconstitution of 1Md-type illite. The diffusion coefficient for continuous argon diffusion is D ⩽10 −28 cm 2 sec −1 . Although the whole-rock ages are dominated by detrital illite, the sediments appear to contain a fine-grained fraction that consists of 1Md illite and mixed-layer clay and gives K-Ar and Rb-Sr ages close to the age of deposition.