CO2 Release Research Articles

A novel socio-techno-environmental GIS approach to assess the contribution of ground-mounted photovoltaics to achieve climate neutrality in Germany

The German government’s goal of achieving climate neutrality by 2045 and increasing the use of renewable energy, particularly wind and solar power, has public support. However, the local siting of wind and solar farms is highly controversial due to land-use conflicts. We have developed a comprehensive Geographic Information System (GIS) model that integrates criteria from the literature to identify optimal locations for ground-mounted photovoltaic (GM-PV). The model is based on a holistic approach considering energy-related factors and broader environmental and climate aspects. The unique feature of the model is its integration of socio-technical and environmental criteria, including a novel approach to achieving a dual land-use climate benefit by protecting erosion-prone soils and conserving soil carbon in areas prone to organic matter decomposition and associated CO2 release. Our multi-criteria GM-PV model includes 12 restrictions and five suitability criteria representing key socio-technical, economic and environmental aspects. Scenario analysis highlights the sensitivity of Germany’s GM-PV potential to defined criteria. In Scenario 1, with minimal constraint, 14.2 % of Germany’s land is available for GM-PV, decreasing to 1.9 % in the highly constrained Scenario 12. Suitable areas (>10 ha) account for 0.4 % of Germany’s land area, which could cover 8.1 % of Germany’s electricity consumption in 2045 in the highly restricted scenario. The spatial distribution results show that the innovative approach of the model changes the preference of GM-PV locations based on factors such as solar radiation in the south and soil carbon storage in the north of Germany. The application of restriction and suitability criteria significantly reduces the potential for GM-PV in Germany but also potential pitfalls for decision-makers. The GIS model can be applied in regional context to integrate stakeholder values and generate region-specific scenarios, as criteria and thresholds can be easily adapted to regional characteristics, preferences, and concerns, including those related to agriculture, biodiversity, and social acceptance.

Unveiling the Activity and Mechanism Alterations by Pyrene Decoration on a Co(II) Macrocyclic Catalyst for CO2 Reduction.

Mechanistic studies involving characterization of crucial intermediates are desirable for rational optimization of molecular catalysts toward CO2 reduction, while fundamental challenges are associated with such studies. Herein we present the systematic mechanistic investigations on a pyrene-appended CoII macrocyclic catalyst in comparison with its pyrene-free prototype. The comparative results also verify the reasons of the higher catalytic activity of the pyrene-tethered catalyst in noble-metal-free CO2 photoreduction with various photosensitizers, where a remarkable apparent quantum yield of 36±3 % at 425 nm can be obtained for selective CO production. Electrochemical and spectroelectrochemical studies in conjunction with DFT calculations between the two catalysts have characterized the key CO-bound intermediates and revealed their different CO-binding behavior, demonstrating that the pyrene group endows the corresponding CoII catalyst a lower catalytic potential, a higher stability, and a greater ease in CO release, all of which contribute to its better performance.

Sustainable Approaches to Prolonging Shelf Life in Green Mature Tomato Fruit

Green mature tomato fruits demonstrate better transportability compared to fully matured ones. This approach has the potential to play a significant role in diminishing postharvest losses and enhancing the accessibility of nutritionally rich fruit in developing countries. The instability of electricity and insufficient cold storage facilities is recognized for fading the shelf life of various fruits and vegetables. However, post-harvest interventions, including tomatoes, can extend perishable products' shelf life. Firstly, tomato fruits were harvested at the green mature stage and stored at 33℃ for 0, 10, 20, and 30 days, followed by a shift to 25℃. Subsequently, ten fruits were subjected to various treatments: A - control (25℃), B - 33℃ with 30-40% RH, C - 33℃ with 50-60% RH, and D - 33℃ with 80-90% RH. Different relative humidity (RH) levels were achieved using saturated salts, specifically MgCl2.6H2O, Mg (NO3)2.6H2O, and KCl+KNO3 for treatments B, C, and D, respectively. The evaluation encompassed parameters such as ethylene production, CO2 release, fruit firmness, weight loss, and color development. A higher temperature, such as 33℃, may be considered advantageous for the storage of green mature tomato fruit. Evidently, tomatoes were successfully stored for over 55 days at this temperature. Across all relative humidity (RH) conditions, there was more noticeable color development in fruits stored at 25°C compared to those stored at 33°C. Among the various RH conditions, fruits stored at 33°C with 80-90% RH experienced the least weight loss, although fruit firmness gradually declined over time. Storing green mature tomato fruit at 33°C with 30-40% RH resulted in the lowest ethylene production compared to 25°C and other RH conditions. Consequently, certain practical benefits of green mature tomato fruit under elevated temperatures and diverse relative humidity (RH) conditions are suggested. However, further detailed research may be necessary to explore potential metabolic changes.

Diurnal Variations and Driving Factors of CO2 Flux at Water–Air Interfaces in the Open-Flow Sections of Karst Underground Rivers

The high-intensity partial pressure of CO2 (pCO2) in karst underground rivers rapidly releases in open-flow sections. This is an important process affecting the global karst carbon cycle. This study focuses on the diurnal variation patterns and driving factors of CO2 exchange flux at the water–air interface in the open-flow sections of typical karst underground rivers in southwestern China. The inorganic carbon in water and water–air interface exchange fluxes are observed. Three representative survey stations, i.e., the outlet of the underground river (Q1), the river sections without submerged plants (H1), and the river sections with submerged plants (H2), are selected to study the CO2 exchange process and its influencing factors. The results show that the CO2 release flux at Q1 exhibits high pressure in the daytime and low pressure in the nighttime, while H1 and H2 exhibit the opposite pattern. The photosynthesis of submerged plants significantly inhibits the carbon release flux of the river, and in the river sections where submerged plants are distributed, their biological effects have inhibited approximately 0.131 Tg C/yr of carbon emissions. This study emphasizes the significant contribution of submerged plants in restraining the release of CO2, thereby promoting carbon sequestration and storage in karst water systems.

Renaissance of fly ash as eco-friendly catalysts for rapid CO2 release from amines

Catalyst-assisted amine regeneration has emerged as a prominent strategy for enhancing the desorption rate of CO2 from amine solutions at lower temperatures (<100 °C), thereby reducing the massive energy penalty of post-combustion carbon capture process. To make this strategy practical and commercially relevant, it is crucial to develop economically viable, abundant, and eco-friendly catalysts. In this context, we synthesized catalysts from fly ash (FA) through treatment with three acidic solutions of H2SO4, H3PO4, and HNO3 and used them in amine regeneration process with evaluating their catalytic performance in terms of CO2 desorption rate, desorbed CO2 quantity, and regeneration heat duty. The acid treatment increased the BET surface area and generated surface acid sites of the FA, both of which played a vital role in increasing the CO2 desorption from monoethanolamine (MEA) solution at 86 °C. The prepared catalysts increased the CO2 desorption rate by up to 91 % and desorbed CO2 amount by up to 61 %, while reducing the regeneration heat duty by up to 38 % compared to the uncatalyzed amine solution. The studied catalysts could be easily separated and used in successive amine regeneration cycles, which makes them suitable for industrial application.

Variation in leaf dark respiration among C3 and C4 grasses is associated with use of different substrates.

Measurements of respiratory properties have often been made at a single time point either during daytime using dark-adapted leaves or during nighttime. The influence of the day-night cycle on respiratory metabolism has received less attention but is crucial to understand photosynthesis and photorespiration. Here, we examined how CO2- and O2-based rates of leaf dark respiration (Rdark) differed between midday (after 30-min dark adaptation) and midnight in 8 C3 and C4 grasses. We used these data to calculate the respiratory quotient (RQ; ratio of CO2 release to O2 uptake), and assessed relationships between Rdark and leaf metabolome. Rdark was higher at midday than midnight, especially in C4 species. The day-night difference in Rdark was more evident when expressed on a CO2 than O2 basis, with the RQ being higher at midday than midnight in all species, except in rice (Oryza sativa). Metabolomic analyses showed little correlation of Rdark or RQ with leaf carbohydrates (sucrose, glucose, fructose, or starch) but strong multivariate relationships with other metabolites. The results suggest that rates of Rdark and differences in RQ were determined by several concurrent CO2-producing and O2-consuming metabolic pathways, not only the tricarboxylic acid cycle (organic acids utilization) but also the pentose phosphate pathway, galactose metabolism, and secondary metabolism. As such, Rdark was time-, type- (C3/C4) and species-dependent, due to the use of different substrates.

Acid‐Unlocked Switch Controlled the Enzyme and CO In Situ Release to Induce Mitochondrial Damage via Synergy

AbstractCO gas therapy has attracted enormous attention in tumor therapy due to the abilities of mitochondrial damage and inhibition of cellular respiration. However, the inefficient and random release of CO greatly limit its application. Taking this into account, the study constructs an acid‐unlocked nanostructure based on MPDA‐MnCO‐GOx@DSNPs, designated as MMGD. The nanostructure enables tumor microenvironment (TME) specific enzyme and CO prodrug (manganese carbonyl, MnCO) cascade reaction, thus facilitating CO release in situ. Mesoporous polydopamine (MPDA) can provide the space for MnCO and glucose oxidase (GOx) loading. Especially, lanthanide (Ln3+)‐doped down‐shifting luminescent nanoparticles (DSNPs) can not only serve as the near‐infrared II (NIR‐II) fluorescence imaging probe, but also act as the acid‐unlocked gating switch. The slightly acidic TME can render the dissociation of DSNPs, thus exposing GOx and releasing MnCO. The catalytic reaction of GOx can produce H2O2 and create a more acidic environment, which facilitates the CO generation in situ, leading to mitochondrial damage by reducing cytochrome c oxidase activity and adenosine triphosphate (ATP) levels. Meanwhile, MPDA has the NIR light absorption capability for photothermal therapy (PTT). This study provides an ingenious strategy for efficient and controllable CO gas, starvation, and PTT of tumor guided by NIR‐II fluorescence imaging.

Mechanical strength changes of combustible municipal solid waste components during their early pyrolysis stage and mechanism analysis.

Implementation of municipal solid waste (MSW) source segregation leads to a more convenient recycle of combustible MSW components. Textiles, plastics and papers are commonly available combustible components in MSW. Their shredding is conducive to resources recovery. But these components usually have high tensile strengths and are difficult to shred. To understand their mechanical strength changes in their early pyrolysis stage will help to address this problem. In this study, a universal electronic testing machine was used to determine the breaking strengths of the materials including cotton towel, polyethylene glycol terephthalate (PET), ivory board (IB), kraft paper (KP) and wool scarf in the temperature range of 30-250°C under N2 atmosphere, and the mechanisms of their strength changes were explored. The reaction force field molecular dynamics (ReaxFF-MD) simulation was used to explain the decomposition behaviours of different sugar groups of hemicellulose in cotton and paper and the change of van der Waals energy of wool during their early pyrolysis stages. The results showed that breaking strengths of all the combustible MSW components reduced as the temperature increased. The breaking strength of PET was found to have the highest descent rate with increasing temperature, then the descent rates of wool and cotton came as the second and third, respectively. Compared with cotton, the breaking strengths of KP and IB decreased more slowly. As the temperature increased, the breaking strength of cotton reduced mainly due to the decomposition of the glucuronic acid in hemicellulose, and the reduction was characterized by CO2 release. The breaking strength reduction of PET was caused by its molecular chain being relaxed. The breaking strength reduction of wool was firstly caused by the decrease in the van der Waals energy between its molecules, and then caused by molecular chain breaking. In addition, in order to understand the influence of material size on the breaking strength change during thermal treatment, the breaking strengths of cotton yarn bundles were correlated with their yarn number and temperature. This study lays the foundation for understanding changes in mechanical strengths of combustible MSW components during their early pyrolysis stage.

Effect of source strength on the simulation of jet dispersion and hazard distances during accidental release of liquid CO2

Accidental release of liquid CO2 can pose a certain risk to people, animals and equipment near release points. In addition to asphyxiation, cryogenic burns and dry-ice inhalation are potential risks that must be considered. In this study, a source model was established considering the formation of dry ice, which can quickly provide the inlet boundary condition for the computational fluid dynamics (CFD) model to simulate the jet dispersion of liquid CO2. The size distribution of the dry ice particles was described by the Rosin-Rammler expression. The effects of size distribution, initial pressure, liquid mass fraction and orifice size on the temperature, velocity, CO2 concentration, mass flow rate (nonsublimated dry ice) and survival distance were analysed. A quantitively risk assessment (QRA) method was used to evaluated the joint impact of source strength, dose-effect and impingement distance. The hazard distances associated with asphyxiation, cryogenic burn and dry ice inhalation were assessed. The results showed that the prediction errors of the mass flow rate using the source model were lower than 20 %. The temperature, velocity and CO2 concentration predicted by the CFD model agree well with the experimental results. The hazard distance was very dependent on and sensitive to the source strength and dose-effect.

A Sustainable and Versatile Cellulose-based CO Surrogate for Carbonylative Reactions.

The highly toxic and flammable nature of CO lead to high handling demand for its use and storage, undoubtedly constricting its further academic exploration for carbonylative reactions in laboratory. Although many CO surrogates have been developed and applied in carbonylative reactions instead of CO gas, exploration of more versatile CO surrogates for diverse carbonylations is still highly desirable. Here we report a cellulose-based CO surrogate (cellulose-CO), which prepared from cheap and abundant cellulose through a simple and green process. The very mild and efficient CO release makes this reagent a highly competitive candidate for providing CO in carbonylation. This surrogate is compatible with a wide variety of functional groups in various carbonylative reactions due to the excellent compatibility of cellulose-CO. Moreover, the cellulose-CO exhibits excellent chemical stability which can be stored exposed to air for 12 months, making this CO surrogate a robust and general reagent in CO chemistry.

Greenhouse gas levels (CH4 and CO2) in Lagos state and Oyo state, Nigeria

The proliferation of greenhouse gases has emerged as a grave menace to humanity. According to scientists, the concentration of these gases, particularly carbon dioxide and methane, is directly linked to the rapid pace of global warming and climate change. To investigate this matter, a study was conducted utilizing a portable gas detector to measure the levels of carbon dioxide and methane in four locations each in Ibadan and Lagos for three months. Readings were collected at each sampling site three times, with each collection period lasting 5 to 15 min. These readings were taken at intervals of 2 to 3 h over a period of 3 months, while also exploring their correlation with meteorological parameters (Temperature, wind speed and relative humidity). Farms, airports, residential areas, and dump sites were deliberately selected due to their contribution to greenhouse gas emissions. The study yielded the following mean concentrations of CO2 in Lagos: 717.67 ppm in Residential Areas, 751.78 ppm in Farmland, 743.78 ppm at the Airport, and 732.56 ppm at the Dumpsite. Similarly, the mean concentrations of CH4 were 0.14 ppm, 0.30 ppm, 0.36 ppm, and 0.45 ppm, respectively. In Ibadan, the average CO2 concentrations were 676.44 ppm in residential areas, 765.11 ppm in farms, 653.33 ppm at the airport, and 683.67 ppm at the dump site. The average CH4 concentrations were 0.08 ppm, 0.32 ppm, 0.43 ppm, and 0.30 ppm, respectively. Furthermore, significant relationships between CO2 and CH4 with meteorological parameters were observed, with R2 values of 0.200 for CO2 in Ibadan, 0.08 for CO2 in Lagos, 0.56 for CH4 in Ibadan, and 0.35 for CH4 in Lagos. Cities, farms, airports, and landfills are responsible for substantial greenhouse gas emissions. The massive release of CO2 and CH4 has resulted in profound impacts and consequences that fuel climate change. This research provides valuable insights into the issue, consequences, and mitigation strategies pertaining to the reduction and regulation of CO2 and CH4 emissions in Lagos and Ibadan, Nigeria.

Biochar-mediated release of CO2 from monoethanolamine/H2O solution with low energy requirement over ZrO2/SiO2/biochar ternary catalysts

CO2 absorption technology based on amine solutions has sustained appeal due to its high efficiency in post-combustion capture of CO2. However, the high energy penalty of solvent regeneration limits its large-scale industrial application. Therefore, designing inexpensive catalysts to reduce solvent regeneration energy consumption remains challenging. This study reports a recyclable ternary catalyst, ZrO2/SiO2/biochar, which was synthesized by co-pyrolysis of zirconium oxychloride and wheat flour in the presence of SiO2 nanoparticles. The incorporation of biochar improved the distribution of Lewis acidic sites (LAS) and Brønsted acidic sites (BAS). The improved BASs and LASs of ZrO2/SiO2/biochar catalyst were conductive to donate protons or accept electrons and thus, the amount and rate of CO2 desorption from CO2-saturated monoethanolamine (90 °C) were more than 24% and 26% higher, respectively, to compare with the catalyst-free system at the same conditions. As a result, the energy penalty was decreased by about 31%. A biochar-mediated proton-transfer mechanism that the presence of biochar increased the mesoporous proportion, the BAS and L/B ratio as well as the favorable charge transfer was inferred for the ZrO2/SiO2/biochar-catalyzed CO2 release through experimental evidence. The results reveal the role of biochar in solid acid catalysts for CO2 desorption, which will provide a novel strategy for building solid acid catalysts to reduce energy requirements in CO2 capture.

Release of Carbon Dioxide and Water-Soluble Carbon Amended with Rice and Wheat Residues in an Inceptisols of Varanasi

ABSTRACT Crop residues are the main organic source of nutrients in agricultural soils. The active pool of soil organic carbon plays a dominant role in crop production and soil health. Rice and wheat residues were used in 90 days incubation study under controlled conditions (25°C temperature and maximum water-holding capacity) to estimate the release of carbon dioxide and water-soluble carbon in an Indo-Gangetic alluvial soil (Inceptisols) of Varanasi. The experiment was laid out in a factorial completely randomized design with three replications. The rice and wheat residues showed a wide variation in the content of their total carbon (TC), total nitrogen (TN), total phosphorus (TP) and total sulfur (TS). Out of the two crop residues added to the soil, rice residue had higher carbon dioxide-carbon (CO2-C) release than that of the wheat residue over control. Results revealed that conjunctive application of rice residue along with urea (20 kg N ha−1) and Trichoderma viride (10 kg ha−1) had resulted in a higher content of CO2-C (7.44 mg per 100 g per day) at 90 days of the incubation period. The amount of CO2 (mg) released, increases with a combination of crop residues with urea (20 kg N ha−1) and Trichoderma viride (10 kg ha−1) up to 90 days over control. The highest release of CO2 (204.70 mg) was recorded with rice residue treated with urea (20 kg N ha−1) and Trichoderma viride (10 kg ha−1). The study also revealed that the release of water-soluble carbon decreases with an increase in the incubation period irrespective of treatment. At 90 days of the incubation period, the control without any crop residue addition has the highest water-soluble carbon content (459.75 µg/g). The present study indicates that the incorporation of rice and wheat residues along with urea and supplemental decomposers (Trichoderma viride) has the potential to release adequately active organic carbon pool parameters such as CO2 and water-soluble carbon in an Inceptisols of Varanasi region of India.

Coupling data-driven geochemical analysis and ensemble machine learning for automatic identification of oceanic anoxic events

Oceanic Anoxic Events (OAEs) have been recorded across the Phanerozoic and linked with catastrophic events in geological records, including the massive release of CO2 into the atmosphere and mass extinctions of marine animals, particularly during the Cretaceous period (e.g., OAE-2). Overall, the occurrence of OAEs were typically identified based on the deposition of organic-rich black shales, carbon isotopic excursions, and enrichment of redox-sensitive elements. While various OAE intervals have been extensively studied across the Tethys using multiproxy geochemical records, recognizing the expression, and understanding the duration of these events are rather challenging and a subject of active debate. This is further compounded by the time-consuming and expert-demanding analysis to interpret complex geochemical records associated with OAEs. To address these issues, we propose a novel approach by coupling data-driven geochemical analysis and ensemble machine learning to recognize and predict the occurrence of OAE-2 in the Upper Cretaceous based on key geochemical records (δ13Corg, TOC, Mo, V, U) collected from different areas geographically. Considering variation in data availability and completeness, we performed machine learning-based data imputation to fill the gaps in geochemical records without perturbing the overall trends and patterns. With this, our prediction of OAE in various locations using ensemble machine learning, achieving an accuracy of up to 90% in the validation and 78% in the blind test predictions. The model could also match the interpreted OAE-2 intervals from different locations with higher resolution prediction based on the δ13Corg and the TOC as the most important parameters followed by the sensitive redox elements. This suggests that the model utilized similar parameters used by geologists in identifying OAEs, increasing the model interpretability. Application of machine learning and data-driven geochemical analysis could help in providing a robust and time-efficient identification of OAE and find new unexplored OAEs along the stratigraphic records.

N‐Carboxyanhydrides (NCAs): Unorthodox and Useful Reagents for Amide Synthesis

AbstractN‐Carboxyanhydrides (NCAs) are compounds derived from the addition of a carboxylic acid to an isocyanate, and are known to form amides readily with the release of CO2 as a by‐product. NCAs have been known for over 120 years, but despite their lengthy history, have remained so far overshadowed by more traditional approaches to amide bond formation. In this review, the potential utility of NCAs in the context of amide bond formation is reviewed and their preparation, reactivity and practical application are also discussed.

Nonclassical Growth Mechanism of Double-Walled Metal-Oxide Nanotubes Implying Transient Single-Walled Structures.

The formation of imogolite nanotubes is reported to be a kinetic process involving intermediate roof-tile nanostructures. Here, the structural evolution occurring during the synthesis of aluminogermanate double-walled imogolite nanotubes is in situ monitored, thanks to an instrumented autoclave allowing the control of the temperature, the continuous measurement of pH and pressure, and the regular sampling of gas and solution. Chemical analyses confirm the completion of the precursor's conversion with the release of CO2, ethanol, and dioxane as main side products. The combination of microscopic observations, infrared, and absorption spectroscopies with small and wide-angle X-ray scattering experiments unravel a unique growth mechanism implying transient single-walled nanotubes instead of the self-assembly of stacked proto-imogolite tiles. The growth formation of these transient nanotubes is followed at the molecular level by Quick-X-ray absoprtion specotrscopy experiments. Multivariate data analysis evidences that the near neighboring atomic environment of Ge evolves from monotonous to a more complex one as the reaction progresses. The following transformation into a double-walled nanotube takes place at a nearly constant mean radius, as demonstrated by the simulation of X-ray scattering diagrams. Overall, transient nanotubes appear to serve for the anchoring of a new wall, corresponding to a mechanism radically different from that proposed in the literature.

Generic geometrical parametric study of wind-driven natural ventilation to improve indoor air quality and air exchange in offices

Indoor air quality significantly enhances employee productivity and well-being in offices. Existing models and guidelines emphasize wind-driven natural ventilation for air exchange and thermal comfort but often overlook detailed airflow patterns. Understanding airflow dynamics is crucial for designing healthy offices, and offering insights into air exchange processes. This information is particularly valuable in mitigating the impact of CO2 and droplet release from multiple occupants, contributing to the creation of healthier office environments. This study, thus, employs a validated CFD model to investigate the impact of geometrical parameters on wind-driven ventilation in offices. With about 150 cases representing alterations in parameters for single-sided (SV) and double-sided (DV) ventilation, a sensitivity analysis identifies key contributors to airflow patterns. Eventually, while five major categories for the airflow patterns can be identified in the DV cases (i.e., (1) without a weak zone (WZ), (2) with a dominant WZ, (3) with a WZ on bottom side, (4) with a WZ on upper side, and (5) with two WZs on upper and bottom sides), a generic airflow pattern can be barely seen in the SV cases. Moreover, in the DV cases, velocity magnitude is crucial for classification of the outputs. The leeward window geometry influences DV natural ventilation more than the windward window. Furthermore, the room dimensions impact ACH more than SF6 concentration and velocity. In the SV cases, location of the infected occupant dominates air changes per hour (ACH), and theta significantly impacts average velocity in contrast to the DV scenarios.

Corelease of Genotoxic Polycyclic Aromatic Hydrocarbons and Nanoparticles from a Commercial Aircraft Jet Engine - Dependence on Fuel and Thrust.

Jet engines are important contributors to global CO2 emissions and release enormous numbers of ultrafine particles into different layers of the atmosphere. As a result, aviation emissions are affecting atmospheric chemistry and promote contrail and cloud formation with impacts on earth's radiative balance and climate. Furthermore, the corelease of nanoparticles together with carcinogenic polycyclic aromatic hydrocarbons (PAHs) affects air quality at airports. We studied exhausts of a widely used turbofan engine (CFM56-7B26) operated at five static thrust levels (idle, 7, 30, 65, and 85%) with conventional Jet A-1 fuel and a biofuel blend composed of hydro-processed esters and fatty acids (HEFA). The particles released, the chemical composition of condensable material, and the genotoxic potential of these exhausts were studied. At ground operation, particle number emissions of 3.5 and 0.5 × 1014 particles/kg fuel were observed with highest genotoxic potentials of 41300 and 8800 ng toxicity equivalents (TEQ)/kg fuel at idle and 7% thrust, respectively. Blending jet fuel with HEFA lowered PAH and particle emissions by 7-34% and 65-67% at idle and 7% thrust, respectively, indicating that the use of paraffin-rich biofuels is an effective measure to reduce the exposure of airport personnel to nanoparticles coated with genotoxic PAHs (Trojan horse effect).

Influence of ZnO and TiO2 nanoparticles on the performance, combustion and emission characteristics of diesel engine fueled with okra seed bio-diesel

Energy sector is demanding alternate fuel for conventional fuel to solve the problems like environmental pollution, Climate change and the exhaustion of fossil resources. Hence, the search of new fuel is paramount importance. This study aimed to identify a new fuel source from okra plants. Okra oil was extracted from okra seed and Okra biodiesel was prepared by transesterfication process. Okra bio-diesel was added with ZnO and TiO2 particles and its effects on diesel engine performance were examined. Performance study showed that B20 fuel exhibited the lowest BSFC of 0.34 kg/kWh and higher BTE of 33% among the biodiesel blends. Further, a lowest BSFC of 0.31 kg/kWh and BTE of 34% were observed for B20/50 ppm ZnO fuel. Combustion study showed that B20/50 ppm ZnO fuel exhibited the In-cylinder pressure and HRR of 71 bar and 54 kJ/°CA respectively. This is 5.9% and 8% increasing in In-cylinder pressure and HRR respectively, compared to B20 fuel. Emission study reported that the B20/50 ppm ZnO fuel showed the CO, HC and smoke release of 0.22 vol%, 40 ppm and 25 HSU respectively. This is 8.3%, 20% and 10.7% decrease in CO, HC, smoke release respectively, than B20 fuel.

Bioprospecting of sourdough microbial species from artisan bakeries in the city of Valencia

This work describes the characterization of an artisanal sourdough set of bakeries located in the city of Valencia. Culture-dependent and –independent analyses detected Fructilactobacillus sanfranciscensis, Saccharomyces cerevisiae and Kazachstania humilis as dominant species. Nevertheless, specific technological parameters, including backslopping temperature, dough yield, or the addition of salt affected microbial counting, LAB/Yeast ratio, and gassing performance, favouring the appearance of several species of Lactobacillus sp., Limosilactobacillus pontis or Torulaspora delbrueckii as additional players. Sourdough leavening activity was affected positively by yeast counts and negatively by the presence of salt. In addition, the predominance of a particular yeast species appeared to impact the dynamics of CO2 release. Seven important flavour-active compounds (ethyl acetate, 1-hexanol, 2-penthylfuran, 3-ethyl-2-methyl-1,3-hexadiene, 2-octen-1-ol, nonanal and 1-nonanol) were detected in all samples and together with 3-methyl butanol and hexyl acetate represented more than the 53% of volatile abundancy in nine of the ten sourdoughs analysed. Even so, the specific microbial composition of each sample influenced the volatile profile. For example, the occurrence of K. humilis or S. cerevisiae as dominant yeast influenced the composition of major alcohol species, while F. sanfranciscensis and L. pontis positively correlated with aldehydes and octanoic acid content. In addition, relevant correlations could be also found among different technological parameters and between these, volatile compounds and microbial species. Overall, our study emphasises on how differences in technological parameters generate biodiversity in a relatively small set of artisan sourdoughs providing opportunities for excellence and quality baking products.