Organic Elemental Composition Research Articles

Experimental evaluation and numerical comparisons of pine tree leaves, graphene oxide loaded, and E-glass fiber reinforced sandwich composites

The research aim is to develop pure epoxy composites (PEC), PTL-reinforced epoxy composites (PTLEC), PTL-loaded and E-glass fiber- incorporated epoxy composites (PTLEIEC), and PTL- and E-glass fabric and graphene oxide-incorporated epoxy composites (PTLEIEGO) were fabricated through an open molding hand layup technique, and structural, mechanical, and thermal stability were carried out and results were compared. Functional groups such as OH, -C-H, C=O, C=C, and C-OH, were found in PTL. Similarly, the OH, C-H, Si-O-Si, C=O, and C-H present in the PTLEIEGO composites were found through Fourier transform infrared spectroscopy (FTIR). The crystal plane orientations (110) and (220) in the PTLEIEGO composites were found through XRD. The surface morphology and elemental compositions of PTLEIEGO composites were found through field emissions electron microscopy (FESEM) and found the presence of different organic and inorganic elemental compositions such as C, O, Si, Ca, Zn, K, and Br as 77.85, 20.78, 0.33, 0.45, 0.05, 0.05, and 0.50 wt.% through energy dispersive X-ray (EDX) spectroscopy. The DSC and TGA were carried out and found the thermal stability of the composites and the onset melting temperature was found to 353.1˚ C. The maximum tensile strength of PTL, PEC, PTLEC, PTLEIEC, and PTLEIEGO composites was found to be 1.25 MPa, 25 ± 0.5 MPa, 55 ± 0.5 MPa, 93 ± 0.5 MPa, and 120 ± 0.5 MPa as per ASTM D 638. The tensile strength was improved from 1.25 MPa for PTL to 120 ± 0.5 MPa for PTLEIEGO. The FEM results revealed a minimum error of 0 % and a maximum error of 21.38 % compared to the experimental results. The maximum shore D hardness of PEC, PTLEC, PTLEIEC, and PTLEIEGO composites was found to be 55 ± 0.5 SHN, 59 ± 0.5 SHN, 76.1 ± 0.5 SHN, and 81.4 ± 0.5 SHN, respectively, as per ASTM D2240. The flexural strengths of PEC, PTLEC, PTLEIEC, and PTLEIGO composites were found to be 37 ± 0.5 MPa, 43 ± 0.5 MPa, 94 ± 0.5 MPa, and 131 ± 0.5 MPa, respectively, as per ASTM D 790. The new composites would be employed in low-strength structural applications such as panels, cabins, doors, and laptop stands. Highlights The tensile strength of PTL, PEC, PTLEC, PTLEIEC, and PTLEIEGO were found to be 1.25, 25 ± 0.5, 55 ± 0.5, 93 ± 0.5, and 120 ± 0.5 MPa, respectively. The tensile strength of the experimental results was compared with FEM results. The shore D hardness of PEC, PTLEC, PTLEIEC, and PTLEIGO was determined to be 55 ± 0.5, 59 ± 0.5, 76.1 ± 0.5, and 81. 4 ± 0.5 SHN, respectively. The novel composite would be employed in low-strength structural applications such as panels, cabins, doors, and laptop stands.

Tracing the Late Quaternary coastal evolution of Central Kerala, India, around the lost ancient port Muziris using multi-proxy study of the sedimentary archives

The Central Kerala coast in Southwest India serves as a valuable natural archive for studies of the Late Quaternary coastal evolution, palaeoclimate, and maritime trades. The coast is an archeologically and culturally significant region in South India, located in the mouth of the longest river in Kerala, the Periyar River. The riverbank of the Periyar at its mouth is believed to host the ancient port Muziris, whose remnants are found in the areas around where the Periyar River joins the Arabian Sea. Sea level oscillations and climate variabilities in the past have played a pivotal role in the destruction of the Muziris port. Recent excavations unearthed many artifacts from nearby areas of the river confluence; however, the exact location of the port remains unresolved. The present study is an attempt to trace out the coastal evolutionary processes and palaeoclimatic conditions that prevailed in the area during the Late Quaternary period using three drilled cores retrieved from this stretch of the coastal lands. A multi-proxy approach, combining geochemical, mineralogical, palynological, and geochronological tools was used in the study. The Holocene deposit in the study area is composed mainly of sand and clay-dominant sediments that fall within an age range of 1.1–8.1 cal kyr BP, whereas the underlying sedimentary sequence dates to a maximum of 31.5–37.9 cal kyr BP. The inorganic and organic elemental compositions, together with the textural and palynological attributes, indicate that Holocene sedimentation occurred here under fluctuating environmental conditions with significant changes in climate and sea level positions. The upper part of this section bears the signature of the humid depositional environment that prevailed during the Late Holocene when sand-dominated sediments were deposited and brought in under the influence of longshore drift. The sediments from the lower part of the section carry the signature of the Holocene transgression when deposition took place under submerged conditions with considerable marine influence but receiving significant terrestrial inputs. The study highlights the location of the historically significant lost ancient port of Muziris at Kodungallur near the mouth of the Periyar River. A three-fold evolutionary model proposed for the coastal segment revealed that the location of the Muziris port was part of the Periyar River near Kodungallur, as mentioned by the historians, and the settlement near Pattanam may be considered a satellite township of the ancient Muziris port.

Divulging the dust: An examination of particle deposition on soft ocular lens during urban commuting

Air pollution affecting the eye is a relatively new, emerging area of research that has implications for urban commuting and is the key first study. This article emphasizes the importance of understanding the effects of particle deposition on the human eye using soft lenses and their exposure, as well as identifying the chemical, elemental composition, and morphology of particles when commuting over a period of 21-day period. In this study, the focus is on personal sampling with soft contact lenses (42% Hioxifilcon A, 58% H2O) to understand particle deposition on ocular along with cascade to understand cut-off size. Volunteers are used for five different modes, namely bus, open and closed car windows, pedestrian, and two-wheeler. The SEM results show that the morphology in buses, pedestrians and cars are denser, irregular, and nodular, with no or minimal interstitial pores, while the particles in two-wheelers appeared to be fibrous, thin, crystalline, and non-porous ranging from 51.2 nm to 406.3 nm. The ICPMS results show the higher concentration compositions for different commuter types, namely: zinc (0.0562 μg/m3 and 0.1076 μg/m3) for buses and pedestrians, potassium (1.5013 μg/m3) and calcium (2.5892 μg/m3), magnesium (2.978 μg/m3), potassium (4.197 μg/m3), calcium (22.335 μg/m3) and iron (7.526 μg/m3) for two-wheelers. The organic elemental composition from FTIR predominant groups namely carbonyl, carboxylic, OH, N–H, C–H, CC, CO, and C–O. The experiment concludes that travellers in two-wheelers and pedestrians are more susceptible to particle deposits which leads to several ocular effects such as eye-irritation, dryness, and visual impairment.

Characterization of Freisa Wines from Piedmont (Italy) by Aroma and Element Profile

The main purpose of this study was to characterize Freisa red wines from Piedmont (northern Italy) according to their volatile organic compounds (VOCs) and elemental composition. Moreover, the authors investigated whether it was possible to distinguish among the five different DOCs produced in Piedmont on the basis of these chemical parameters. The VOCs profile of Freisa wines was very similar, and the most abundant species detected were isoamyl alcohol, phenylethyl alcohol, ethyl octanoate, and diethyl succinate. Conversely, elemental composition allowed us to partially distinguish one Freisa DOC with respect to the others. Multivariate statistical analysis applied to elemental composition revealed differences among Freisa wines and other red wines from different regions of Italy. In particular, Freisa wines featured higher concentrations of Cr and Ni metals, which are strongly correlated with the composition of the soil of Piedmont. These two elements are hence good candidates as chemical markers for Freisa wines from Piedmont.

Chemical speciation of organic compounds and elemental compositions of PM2.5 in Mexico City: Spatial-seasonal distribution, emission sources, and formation processes

The simultaneous study of n-alkanes, polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, and metals in particles ≤2.5 μm (PM2.5) provided helpful information to identify pollutant emission sources in the Metropolitan Zone of Mexico Valley (MZMV). PM2.5 samples were obtained during three seasons of a year from five sampling sites simultaneously collected. The dominant sources of the species were the incomplete combustion of fossil fuel by vehicles, followed by the resuspension of geogenic material, evaporation from petrogenic sources, and emissions from the oil refining industry. The northeast (NE) of the MZMV, hosting the industrial area, exhibited the highest contribution of ΣPAHs<228 due to the high presence of diesel vehicles. The NE also showed the highest metal concentrations of geogenic origin due to its proximity to agricultural lands and the dominant wind direction from the north to the south, introducing pollutants into the Valley. Among the pollutants, 1-nitropyrene emitted from diesel combustion sources and 2-nitrofluoranthene formed in the atmosphere were found. Particles enriched with Mn + Fe + Co + Cu and Rb were emitted from agricultural lands and volcanic soil, respectively, and originated from local/peripherical soils, while particles enriched with Cr + Cs + Th were originated from geogenic sources further away from the MZMV. Cd + Pb and n-alkanes C16-C22 were emitted outside the Valley, while PAHs, nitro-PAHs, and heavier n-alkanes (C23-C33) were emitted inside the Valley. Decision-makers could use our results to develop control strategies for air pollutants from specific sources. Comparisons of hydrocarbon and metal concentrations in other cities were also made.

Anaerobic degradation of hexachlorocyclohexane: Factors influencing the reactor start-up

This study examined the anaerobic degradation of technical-hexachlorocyclohexane (t-HCH)-a persistent organic pollutant (POP), using a batch reactor and the influence of pH, active biomass as volatile suspended solids (VSS), total suspended solids, total organic carbon, chloride release, and elemental composition on an Upflow Anaerobic Sludge Blanket (UASB) reactor start-up. Chloride release, a direct indicator of HCH degradation, was measured to confirm the process. During the initial sludge acclimatization, only 49.23 % degradation efficiency was seen after 45 days with an initial concentration of 1.0 g l−1. However, when electron donors and co-substrates were added to the sludge, the degradation time was shortened to 15 days with an increase in efficiency up to 60.17 %. When this adapted sludge was taken in a UASB reactor start up at 100 mg l−1 HCH, this degradation effectiveness was significantly improved when organic loading rate (OLR) was decreased to 50 mg l−1 d−1 assuming 48 h hydraulic retention time (HRT) in a UASB reactor start up at 100 mg l−1 HCH. During the original UASB reactor start-up, 92.37 %, 90.64 %, 85.72 %, and 83.26 % degradation of the alpha, gamma, beta, and delta isomers, with evidence of pentachlorocyclohexene as a transitory intermediate was observed. The major determining variables for reactor start-up were found to be neutral pH, mesophilic temperature, addition of co-substrate (glucose), VSS, HRT, and OLR. The study's innovation is that it examines the efficacy of the degradation process during sludge acclimatization and gives useful details about the variables to consider when starting up a UASB reactor. This research gives a biodegradation trend, which may be required before venturing for anaerobic degradation of recalcitrant substances like t-HCH.

Genetic variability, biomass parameters, elemental composition and energy content of the non-indigenous hydromedusa Craspedacusta sowerbii in North America

Abstract The freshwater hydrozoan Craspedacusta sowerbii was introduced to habitats around the world and they spread into the surrounding water bodies thereafter. Despite an increase in reported observations, little is known about its genetics, physiology and ecology. The present study examined the organic content, elemental composition and energy content of jellyfish collected in Canada and the USA and compared these metrics with their marine counterparts and other co-occurring zooplankton. Specimens from the sampled lakes were sexed and molecularly characterized. Molecular, stoichiometric and energetic information is critical in determining distribution pathways and trophic connections. Molecular analyses showed two closely related sequences in North America, one shared by the Canadian and Japanese specimens, while another one is widely present across the Americas. Organic and all elemental contents were higher compared to marine jellyfish species. Estimated energy content of C. sowerbii was 20–27 kJ g DW−1, which is 2-fold higher than for marine hydrozoans and compared well with cladocerans, copepods and rotifers. Estimated C/P values indicated that cladocerans and copepods are suitable prey for C. sowerbii and that jellyfish may compete with juvenile fish to fulfill similar nutrient demands. Freshwater jellyfish were stoichiometrically and energetically different from marine hydrozoans, indicating higher importance in freshwater food webs than previously thought.

Development of an Integrated Platform to Assess the Physicochemical and Toxicological Properties of Wood Combustion Particulate Matter.

Wood burning contributes to indoor and ambient particulate matter (PM) pollution and has been associated with increased morbidity and mortality. Here, we present an integrated methodology that allows to generate, sample, and characterize wood smoke derived from different moisture contents and representative combustion conditions using pine wood as a model. Flaming, smoldering, and incomplete combustion were assessed for low-moisture pine, whereas both low-moisture pine and high-moisture pine were investigated under flaming conditions. Real-time monitoring of carbon monoxide, volatile organic compounds, and aerosol number concentration/size in wood smoke was performed. The PM was size-fractionated, sampled, and characterized for elemental/organic carbon, organic functional groups, and inorganic elements. Bioactivity of PM was assessed by measuring the sterile alpha motif (SAM) pointed domain containing ETS (E-twenty-six) transcription factor (SPDEF) gene promoter activity in human embryonic kidney 293 (HEK-293T) cells, a biomarker for mucin gene expression. Findings showed that moisture content and combustion condition significantly affected the organic and inorganic elemental composition of PM0.1 as well as its bioactivity. Also, for a given moisture and combustion scenario, PM chemistry and bioactivity differed considerably with PM size. Importantly, PM0.1 from flaming combustion of low-moisture pine contained the highest abundance of the oxygenated saturated aliphatic functional group [H-C-O] and was also biologically most potent in stimulating SPDEF promoter activity, suggesting the role of organic compounds such as carbohydrates and sugar alcohols (that contain [H-C-O]) in driving mucus-related respiratory outcomes. Our platform enables further well-controlled parametric studies using a combination of in vitro and in vivo approaches to link wood burning parameters with acute and chronic inhalation health effects of wood smoke.

Silica crystallinity: Characteristics and controlling factors in marine shale of the upper Yangtze area, China

The quartz crystallinity index (QCI) was applied to quantitatively characterise the crystallinity features of silica within the marine shale of the upper Yangtze area. A total of 67 samples, including 63 shale samples, 3 quartz vein samples, and 1 artificial quartz sample as reference, were applied in QCI calculation by X-ray diffraction (XRD). Furthermore, based on the identification and classification of graptolite biozones, a series of experimental analyses, including the total organic carbon (TOC) content, bitumen reflectance, and elemental composition, were conducted to determine the silica origin and controlling factors of crystallinity. The results indicated that biogenic silica in marine shale intervals had an obviously lower crystallinity than silica of other origins. The quartz vein in shale intervals presented the highest silica crystallinity. Silica that experienced a low diagenesis intensity exhibited the lowest crystallinity. Furthermore, biogenic silica in a state of overpressure had a much lower crystallinity than that under normal pressure. The crystallinity of silica in marine shale of the upper Yangtze area is affected by origin, diagenesis intensity, and overpressure. From the perspective of QCI, the Chengkou area is probably the next favourable area for shale gas exploration and development.

Identifying the influence of terrestrial–aquatic connectivity on palaeoecological inferences of past climate in Arctic lakes

Increased hydrological connectivity due to permafrost degradation is likely to have substantial implications for shallow aquatic systems common to sub‐arctic landscapes due to changes to overland and subsurface flow of water and transport of sediments and dissolved nutrients. Here, we explore the influence of increased connectivity on aquatic productivity based on multi‐parameter palaeolimnological analysis of two lakes located near Inuvik (Northwest Territories, Canada). We contrast a lake with little evidence of permafrost degradation in the surrounding area (Lake PG03) to one that has multiple connections to the terrestrial landscape through a network of thaw polygons in the lake catchment (Lake PG09). Comparisons of biological indicators (chironomids) and organic carbon and nitrogen elemental and isotope composition reveal recent divergent lake histories. The chironomid assemblage of Lake PG03 followed an expected temperature gradient, with a warming signal evident since ˜1970 CE, whereas the chironomid assemblage of Lake PG09 was found to primarily respond to nutrient availability and changes in habitat, likely as a result of increasing hydrological connectivity to the landscape. Rapid assemblage and habitat change along with a prominent increase in chironomid abundance were observed at Lake PG09 after ˜1960 CE, following a shift to greater inputs from the terrestrial environment as indicated by high C:N ratios (&gt;15) and low δ13Corg (−30‰). Increased aquatic productivity following high allochthonous additions (˜1960–2014 CE) is supported by decreased C:N and rapidly increasing organic matter (Corg, N). These results demonstrate that increased connectivity along the terrestrial–aquatic interface for lakes is likely to foster elevated productivity in the future. Likewise, increased production poses a challenge to chironomid‐inferred July air temperature reconstructions in lakes that are less resilient to secondary gradients, where analogue mismatches can occur due to shifts in dominance of indicators that are orthogonal to the temperature gradient.

Natural and anthropogenic risks after a giant landslide in the Russian Far East

At the Bureiskoe Reservoir (Far East, Russia) in December 2018 at a temperature of 36°C below zero the giant landslide is occurred. Landslide with a total volume of 24.5 million m3 blocked the reservoir from one shore to the opposite one, disrupting the access of water to a large hydroelectric power station downstream. Blasting operations were carried out with the use of trinitrotoluene and hexogen to revive the water flow. As a result of the landslide natural hazards (direct impact of the landslide, and tsunami) were happened, and the further strong impact was caused by humans (blasting). Volatile organic compounds (VOCs) and elemental composition were accepted as the main indicators of water quality. Parameters of these indicators varied at different near-shore sites above and below the landslide area. More significant changes are recorded after blasting operations. Hexane and toluene dominated the water passing the artificial channel. The genesis of VOCs can be associated with the biogeochemical processes of methanogenesis, methanotrophy, and the detonation products of explosives. Mercury, methanol, toluene, and xylenes in water samples were detected. This is evidence of the presence of a prerequisite for the formation of toxic methylmercury, a risk factor for aquatic biota.

Comparison of emissions from smokeless coal combustion in a household heating boiler used in Central Europe

The objective of this work was to evaluate the relationship between the fuel quality and the gaseous and particulate pollutant emissions generated from a hot-water boiler during the combustion of different types of innovative processed fuels: smokeless coal, smokeless briquettes 1–3, smokeless pellets and unprocessed hard coal. The aim of our research was to prove the presumption that smokeless processed coals produce less gaseous and particulate emissions. By using modern fuels in already used and manufactured older boilers, there is a possibility to significantly reduce emissions of organic gaseous compounds (OGC) and polycyclic aromatic hydrocarbons (PAHs). The emission situation in the heating season can be significantly improved even without costly production, and thus consumption of natural resources and energy, and installation of modern boilers. Physical and chemical characterization of solid-fuel samples, including determination of moisture content, ash, volatile organic content, calorific value and elemental composition analysis, were performed. Fuels were burned in one type of hot-water boiler class 1 according to EN 303-5 to determine the impact of applied fuel types on pollutant emissions. The pollutant emissions were characterized by the contents of gaseous components: nitrogen oxides NOx, sulfur dioxide SO2, carbon monoxide CO, carbon dioxide CO2, organic gaseous compounds OGC and particle components: total suspended particles TSP, particulate matter less than 2.5 µm and 10 µm (PM2.5 and PM10, respectively) and polycyclic aromatic hydrocarbons PAHs in both phases. The emission factors from six types of fuel were compared with applicable European standards. The lowest NOx content was observed for smokeless briquette 1, while the lowest SO2 content was observed for smokeless pellets. The emission of CO was at a similarly low level of 200 g/kg for smokeless briquette 1, smokeless briquette 2 and hard coal. Gaseous and pollutant emissions described by PM2.5 and TSP were observed to be the lowest for smokeless coal, smokeless briquette 1 and smokeless briquette 2.

Studying the effect the physicochemical properties of fine size raw coal organic and mineral composition have on beneficiation efficiency

Introduction. This work presents the results of the research on the effect the petrographic characteristics, elemental and mineral composition have on the Kedrovsko-Krohalevskoe fine coal beneficiation efficiency. The data has been analyzed of raw coal physochemical properties at the stage of mining and dressing mill raw material base formation. Research objective is to study thermal coal by physicochemical methods of analysis to identify the main parameters affecting the quality of beneficiation products. Based on the data obtained, the research aims to develop the method of assessing the indicators affecting the beneficiation process and further forecasting during the development of new areas and coal seams. Methods of research. The structural features of raw KCN (coking low-caking low-metamorphosed) coal were determined by comparative analysis of three samples according to the following parameters: laboratory flotation results, general technical parameters, maceral composition, organic matter elemental composition, and ash mineral composition. Results. It has been established that coals of a similar nature of origin and stage of metamorphism, can have different indicators in vaarious parameters: particle size, number and morphology of microcomponents according to quantitative petrographic analysis, as well as the presence of hydrophilic functional groups on the surface of coals. Conclusions. The results of the studies made it possible to identify a number of dependencies that can be used in a preliminary assessment of the quality of raw coal sent to a coal processing enterprise.

Improving anaerobic digestion mass balance calculations through stoichiometry and usual substrate characterization

In recent years, anaerobic digestion (AD) of organic waste has raised as a winning strategy to produce energy and organic fertilizer. To optimize such a technology, mass balance is needed to model or simply monitor the process. This paper describes a theoretical framework allowing process indicators to be derived from estimates of organic waste elemental composition. Using a database of 128 typical feedstocks, semi-empirical equations are provided to estimate this elemental composition in case of a missing analysis. Then, a revised stoichiometric reaction of anaerobic digestion is proposed considering biomass yield and nitrogen. Biomass yield induces a more accurate estimation of the ammonia production and the volatile solids (VS) loss. The stoichiometric reaction allows the prediction of biogaz quality and mass loss and a correction factor for VS removal is proposed. The use of real case studies highlights the need to consider this correction (correction factor range: 1.01–1.2), especially for dry AD.

Geochemical, petrographic and reservoir characteristics of the transgressive systems tract of lower Silurian black shale in Jiaoshiba area, southwest China

In recent years, lithofacies identification and classification have been a hot topic in shale gas research. Even if some previous works are considering the distribution characteristics of lithofacies in different system tracts (third-order sequences), only few studies systematically reveal the lithofacies distribution and reservoir characteristics. In this study, we focus on transgressive systems tract (TST) section which is characterized by high TOC content and highest gas content in the Long-1 member and divided the third-order TST into five Units (parasequences) according to graptolite biozonation, gamma ray (GR) and acoustic (AC) logging data. Twenty-six samples were analyzed for total organic carbon (TOC) content, mineral and elemental composition, porosity, pore type, pore size distribution and pore connectivity. The results show that Unit 1 is predominantly composed of S-3 and S-4 lithofacies, and Units 2–5 is predominantly composed of S-4 and M-2 lithofacies. The S-4 lithofacies was associated with high primary productivity of organic matter, and anoxic bottom water conditions. Redox conditions changed from anoxic to dysoxic condition and the productivity decreased through Unit 1 to Unit 5. Compared to other units, Units 1 and 2 are characterized by higher porosity and better pore connectivity. The S-3/S-4 and M-2 lithofacies exhibit different reservoir quality, especially in pore structure. Mineralogical composition is the key factor to determine lithofacies type and affects the characteristics of pore structure. Besides, TOC plays an important role in the development of organic matter pores. Anoxic bottom water conditions and high paleo-salinity contributed to the preservation of organic matter.

About Possibility to Use Industrial Coal-Rank Classification to Reveal Coal Layers Hazardous Characteristics

The research is concerned with all the fossil coal metamorphism series based on their rank classification. Currently, based on the genetic characters of metamorphic coal conversions, no proved regulatory definition of the coal layer hazardous characteristics is available. For mining forecasts, the regulatory framework uses a limited number of the classificatory parameters with properties, which have not been determined for the whole multiplicity of coals metamorphic transformation. Special features of each coal rank shall be specified using their proxy parameters. It proves that they specify different aspects of the metamorphic coal conversions, as well as other classificatory parameters. For proved forecasting the coal layer hazardous characteristics, it is necessary to use some combinations of the classificatory parameters. It is testified that any alterations of coal properties due to their inner structure conversions may be characterized by maximum and minimum values of different parameters for the same coal rank. The limit for possible alteration of the K rank coals volatile mass yield has been established in lower than normal level. It is noted that coals with the same consumer performance may in some cases be characterized by different values of the classificatory parameters, and in other cases—the coals with different values of the classificatory parameters may have the same processing behavior. It is proposed, when establishing any hazardous properties of the coal layers in addition to the industrial classificatory parameters, one should use alterations of the organic part elemental composition, mineral impurities and moisture in the whole range of metamorphism series.

Gelatinous and soft-bodied zooplankton in the Northeast Pacific Ocean: organic, elemental, and energy contents

Gelatinous and soft-bodied zooplankton (GZ) have long been considered to have low energetic value (‘trophic dead end hypothesis’) and be insufficient to sustain higher trophic levels. However, the nutritional composition and energy content of GZ are often poorly known for entire groups, ignoring species-, size-, and stage-specific differences. In this study, organic matter and elemental composition (carbon and nitrogen) were measured for &gt;1000 specimens from 34 GZ species collected from neritic and oceanic waters of the Northeast Pacific between 2014 and 2020. Species included 3 gastropods, 16 hydrozoans, 2 nude ctenophores, 6 scyphozoans, 3 tentaculate ctenophores, and 4 thaliaceans. Organic content and elemental composition were used to estimate energy content using published conversion factors and differed between and within taxonomic classes. Size-dependent variability was shown for several species. Differences in organic content and elemental composition by development stage were observed in a salp and scyphomedusa species, highlighting the need to consider life cycle stages separately. The relative energy values of GZ were generally low and highly variable, although some taxa were comparable to crustaceans. The findings of the present study emphasise the need for a more detailed consideration of GZ in marine food web models and time series analyses, to take into account their inter- and intraspecific variability.

Optical Characterization of Biomass Soot Samples

Soot from different biomass sources is investigated to develop absorbent coatings for use in solar cookers. Soot samples were analysed by spectral and solar reflectance in the range 280-2400 nm, by its organic elemental composition and through Raman spectroscopy. The soot was obtained from biomass burning of sugarcane, pine resin and firewood in a hearth. The averaged spectral reflectance for sugarcane soot is 3.5%, for wood-stove soot is 2.7% and the lower value corresponds to pine resin soot at 1.4%. Likewise, the lowest value of the solar reflectance was of 14.8 Wm−2 for pine resin soot. In addition, elemental composition analysis showed that pine resin also has the highest carbon content. Raman spectroscopy measurements were performed to find the structure and the degree of disorder in the graphite structure.

Comparative of Different Drying Methods on the Phytochemical and Some Nutrient Components of Scent Leaf (Ocimum gratissimum)

The effect of air, sun, and oven drying methods on scent leaf (Ocimum gratissimum) and the organic and dietary elemental composition of its leaves was evaluated using standard analytical procedures. Drying increased significantly and the concentration of organic constituents evaluated. The ash content was markedly enhanced by drying and it range from 2% in the fresh sample to 11.5% in the oven-dried sample, the fiber content range from 1.5% in the fresh sample to 5.5% in the air-dried sample, also the lipid content from 0.5% in fresh sample to 2.5% in both air-dried and oven-dried sample, the moisture content was markedly low in the drying method compared to the fresh, the carbohydrate content range from 9.46% in the fresh sample to 76.20% in the sun-dried sample, the protein content ranging from 1.54% in the fresh sample to 2.80% in the sun-dried sample. Preserving Ocimum gratissimum leaves in a more hygienic way and ensure its all-year round availability and possible elimination of most nutrient deficiencies. A significant increase in mineral content was observed upon drying except for K and Ca whose concentration was found to be high (2050±0.003 mg/kg and 1.50±0.003 mg/kg) in the fresh sample and observed low in the dried samples. All the results are expressed in MEAN±SEM (Standard Error of Mean) and a significant difference was observed among the drying methods. The result of this study suggest that drying methods increase the concentration of organic and dietary elemental compositions.

Identifying recent sources and fate of sedimentary nitrogen in the Baltic Sea based on organic matter elemental composition and nitrogen and carbon stable isotopes ratios

Sedimentary nitrogen (SN) provenience and fate in surface and subsurface sediments collected from the Baltic Sea were assessed. SN and sedimentary organic carbon (SOC) concentrations, stable isotopic signatures (δ15NSN and δ13CSOC) and SOC/SN molar ratios, were determined in subsequent layers of twenty-four sediment cores dated with 210Pb/137Cs and fifty-seven surface sediments. Sedimentation rates in the range 66–736 g/m2yr−1 (0.05–0.34 cm/year) were measured. Prolonged incubation of sediments in the laboratory led to a 17–37% decrease of SN in surface sediments, and no SN loss in sediments deposited before 1940. Decrease of δ15NSN on incubation (1‰ on average), and gradients of δ15NSN, between recent - surface (3.5‰) vs. 100 years old - subsurface (2.1‰) sediments were attributed to varying contributions of labile nitrogen to the SN pool. Annual deposition of SN to sediment surface and burial in subsurface sediments amounted, respectively, to 5 ± 2 g/m2 and 3.5 ± 1 g/m2.