Undesired Products Research Articles

Insights into the Synthesis of a Semiconducting Nickel Bis(dithiolene) Coordination Polymer.

Nickel bis(dithiolene) complexes are promising candidates for novel n-type semiconductors, which are air-stable and highly conductive. A key issue for further development is that their synthesis often yields undesired products, greatly limiting the degree of polymerization as well as purity and adversely affecting their electronic properties. Crucially, there is a lack of in-depth identification of these species and understanding of the reaction mechanism. This study explores the mechanism of a reaction forming the coordination polymer nickel-thieno[3,2-b]thiophenetetrathiolate (Ni-TT). We find that the Unoxidized Ni-TT intermediate contains negatively charged polymer chains with Ni2+ counter cations. Oxidation in the final synthetic step occurs primarily at the ligand, resulting in a more neutral Ni-TT. Our investigation also reveals that the ligand can form dimeric and trimeric species via disulfide bonds as byproducts. These insights are pivotal knowledge to develop metal bis(dithiolene)-based coordination polymers to achieve purity and quality required for electronic applications.

Engineering the electron localization of metal sites on nanosheets assembled periodic macropores for CO2 photoreduction

Photocatalytic conversion of CO2 into syngas is highly appealing, yet still suffers from the undesirable product yield due to the sluggish carrier transfer and the uncontrollable affinity between catalytic sites and intermediates. Here we report the fabrication of Co sites with tunable electron localization capability on two dimensional (2D) nanosheets assembled three dimensional (3D) ordered macroporous framework (3DOM-NS). The as-prepared Co-based 3DOM-NS catalysts exhibit attractive photocatalytic performances toward CO2 reduction, among which the cobalt sulfide one (3DOM Co-SNS) shows the highest syngas generation rate up to 347.3 μmol h−1 under the irradiation of visible light and delivers a remarkable catalytic activity (1150.7 μmol h−1) in a flow reaction system under natural sunlight. Mechanism studies reveal that the high electron localization of metal sites in 3DOM Co-SNS strengthens the interaction between Co and HCOO* via the orbital interactions of dyz/dxz-p and s-s, thus facilitating the cleaving process of C-O bond. Additionally, the ordered macroporous framework with nanosheet subunits elevates the transfer efficiency of photoexcited electrons, which contributes to its high activity.

Effects of wheat cultivar, bran concentration and endoxylanase on the thermomechanical, viscoelastic and microstructural properties of whole wheat flour dough

Globally, it is challenging to promote the market of whole wheat product due to its undesirable product quality issues. To overcome this remarkable challenge, this research was to work on the constructive strategies for mitigating the negative impact of wheat bran. As such, the objective of this research was to investigate how the wheat cultivar, bran concentration and endoxylanase affected dough thermomechanical properties, viscoelasticity and microstructure by a combined use of mixolab, rheometry, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). A cultivar-dependent discrimination for the bran tolerance was observed to suggest the suitable wheat cultivars for whole wheat manufacturing. Bran addition positively affected dough mechanical and viscoelastic properties, i.e., larger dough mechanical weakening (C2) and gel strength, and it negatively affected starch gelatinization (C3) and retrogradation (C5). However, the main conclusions are below. The endoxylanase was incorporated to invert the bran impact on the above properties of dough. Endoxylanase was also used to develop a better integrity of gluten network, larger coverage of starch granules and even distribution of gas cells. Outcomes from this work will provide a practical guidance for improving the high-fibre product quality and promoting its market growth.

Atomically dispersed nickel in CeO2 aerogel catalysts completely suppresses methanation in the water-gas shift reaction.

Nickel-based catalysts are widely studied for water-gas shift (WGS), a key intermediate step in hydrogen production from carbon-based feedstocks. Their viability under practical conditions is limited at high temperatures when Ni aggregates and converts CO to methane, an undesirable side product. Because experimental and computational studies identify undercoordinated Ni step sites as most active toward CH4 formation, we eliminate Ni step sites by atomically dispersing Ni into networked, nanoparticulate CeO2 aerogels. The mesoporous catalyst with 2.5 atomic % Ni in CeO2 is highly active for WGS, converting near-equilibrium levels of CO at 350°C, while no CH4 is detected at the limit of detection (<2 parts per million). In contrast, supporting low weight percentages of Ni clusters or nanoparticles on CeO2 aerogels leads to methanation. The CH4 yield produced by the atomically dispersed Ni-substituted CeO2 aerogel is over an order of magnitude lower than previously reported Ni-based catalysts claiming methane suppression, marking an important advance in the development of WGS catalysts.

The Stability Challenge of Furanic Platform Chemicals in Acidic and Basic Conditions.

The transition toward renewable resources is pivotal for the sustainability of the chemical industry, making the exploration of biobased furanic platform chemicals derived from plant biomass of paramount importance. These compounds, promising alternatives to petroleum-derived aromatics, face challenges in terms of stability under synthetic conditions, limiting their practical application in the fuel, chemical, and pharmaceutical sectors. Our study presents a comprehensive evaluation of the stability of furan derivatives in various solvents and under different conditions, addressing the significant challenge of their instability. Through systematic experiments involving GC-MS, NMR, FT-IR and SEM analyses, we identified key degradation pathways and conditions that either promote stability or lead to undesirable degradation products. These findings demonstrate the strong stabilizing effect of polar aprotic solvents, especially DMF, and reveal the dependence of furan stability on solvent and additive type. This research opens new avenues in the utilization of renewable furans by providing critical insights into their behavior under synthetic conditions, significantly impacting the development of sustainable materials and processes. The broad appeal of this study lies in its potential to guide the selection of conditions for the efficient and sustainable synthesis of furan-based chemicals, marking a significant advance in green chemistry and materials science.

The Yin and Yang of banking: Modeling desirable and undesirable outputs

This paper introduces a novel by-production approach to modeling desirable and undesirable output production processes in the US banking sector. We utilize the structural proxy variable framework in which desirable outputs (different types of loans and other income-generating activities) are exogenous, which is a common practice in the banking literature. The undesirable output is non-performing loans (NPLs). To address the endogeneity of variable inputs (purchased funds and core deposits) in the production of desirable outputs, we employ an input distance function and rely on the bank’s cost-minimizing behavioral assumption. We specify the undesirable output technology as a function of desirable outputs as well as other factors such as total non-transaction accounts, undivided profits, and capital reserves. Using US commercial bank data from 2001 to 2020, we find that bank productivity exhibits steady growth in desirable outputs. Banks prioritize reducing the overall productivity impact of NPLs post-crisis, shifting focus from pre-crisis service provision.

Isolated Ni Atoms for Enhanced Photocatalytic H2O2 Performance with 1.05% Solar-to-Chemical Conversion Efficiency in Pure Water.

Photocatalytic hydrogen peroxide (H2O2) production encounters a major impediment in its low solar-to-chemical conversion (SCC) efficiency due to undesired H2O2 product decomposition. Herein, an isolated nickel (Ni) atom modification strategy is developed to adjust the thermodynamic process of H2O2 production to address the challenge. Sacrificial experiments and in situ characterization reveal that H2O2 generation occurs via a highly selective indirect two-electron oxygen reduction reaction. The optimized photocatalyst exhibits a remarkable H2O2 production rate of 338.9 μmol gcat-1 h-1 in pure water, representing a 48-fold enhancement. Notably, it attains an impressive SCC efficiency of 1.05%, surpassing that of current state-of-the-art catalysts. Theoretical insights reveal the downshifted d-band center facilitates moderate O2 adsorption and barrier-free *OOH conversion, favoring H2O2 release and preventing *H2O2 decomposition. This work showcases efficient H2O2 photosynthesis via d-band manipulation, presenting a fresh perspective for advancing high-efficiency SCC systems.

Influence of Ensiling Timing and Inoculation on Whole Plant Maize Silage Fermentation and Aerobic Stability (Preliminary Research)

Despite efforts to prevent atypical ensiling conditions, such as delayed ensiling or sealing, these issues frequently occur in practice. This study aimed to investigate the effects of delayed ensiling (forage held for 24 h) and sealing, along with inoculation using a blend of Lentilactobacillus buchneri and Lactococcus lactis, on the characteristics of the resulting silages. Whole-plant maize (Zea mays L.) was treated with or without a commercial inoculant and ensiled (36% dry matter) for 60 days in 3.0 L glass containers. The forage was either ensiled immediately or subjected to a 24 h delay before ensiling. During the delay, the forage was either covered or left uncovered. Each treatment was replicated five times. All data were analyzed using the MIXED procedure of SAS statistical software (version 9.4; SAS Institute Inc., Cary, NC, USA). Delaying the ensiling process by 24 h worsens fermentation parameters, significantly increases dry matter (DM) losses (p &lt; 0.01), and significantly reduces aerobic stability and the hygienic quality of the silage (p &lt; 0.01), as evidenced by higher concentrations of undesirable fermentation products and elevated yeast and mold counts. The inoculation has a significant impact on both forage before ensiling and the characteristics of the resulting silage. Maize forage treated with inoculant showed a lower temperature increase by 8.2–8.1 °C (p &lt; 0.01) when delayed for 24 h before ensiling. In silages, it also resulted in a reduced pH (p &lt; 0.01); increased concentrations of lactic acid; acetic acid; and 1,2-propanediol (p &lt; 0.01); and decreased levels of negative fermentation indicators such as ammonia-N, alcohols, and butyric acid (p &lt; 0.01) During both the fermentation and aerobic exposure periods, inoculated silages exhibited up to 36% and 2.6 times lower (p &lt; 0.01) dry matter loss, while suppressing the growth of yeasts and molds by up to 2.6 and 3.1 times (p &lt; 0.01), respectively, compared to non-inoculated silages. The results of this study support the recommendation to minimize the duration of aerobic exposure of fresh forage during silo filling and to use LAB-based inoculants.

Effect of super absorbent polymers on the self-healing capability of macrocracked ultra-high performance concrete under highly aggressive environments

In this study, the performance of superabsorbent polymers (SAPs) as self-healing agents in macrocracked ultra-high performance concrete (UHPC) was extensively evaluated, with a focus on compressive strength behavior in different aggressive environments. Three UHPC mixtures were designed: a control mixture, a UHPC with 0.3 % sodium polyacrylate (poly(AA)), and a UHPC with 0.3 % polyacrylate-co-acrylamide (poly(AA-co-AM)). Samples with macrocrack widths of 0.3 mm, 0.5 mm, and 1 mm, as well as uncracked samples, were prepared. The samples underwent immersion in deionized water, chloride saltwater, and compound saltwater. The performance of self-healing was evaluated by measuring crack closure rates, recovered compressive strength, and stereomicroscopic inspections. Further, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDX) was performed to monitor mineral formation and the healing process. The results indicate that both poly(AA) and poly(AA-co-AM) SAPs significantly enhanced the self-healing capabilities of UHPC, with poly(AA) demonstrating superior performance. Self-healing was more pronounced in samples with cracks width of 0.3 mm, whereas samples with cracks widths of 0.5 mm and 1.0 mm exhibited incomplete and negligible healing, respectively. The healed samples recovered a substantial portion of their compressive strength, regardless of the crack width. However, the presence of chloride and/or sulfate ions was found to impede the self-healing process. As observed from the SEM/EDX results, in addition to CaCO3 and C-S-H gel, undesirable healing products like Friedel’s salt and ettringite were also formed in chloride and compound saltwater environments which significantly affected self-healing durability.

Furanic jet fuels – Water-free aldol condensation of furfural and cyclopentanone

A method for the water-free, large-scale synthesis of bio-jet fuel precursors, distinct from traditional fossil-based sources, is introduced. This approach involves the aldol condensation of furfural with cyclopentanone, producing C10-C15 fuel precursors eligible for further hydrodeoxygenation to high-performance diesel and jet fuel hydrocarbons. In the context of process integration, aldol condensation reactions were conducted under water-free conditions, utilizing excess furfural as the solvent. Evaluation of various commercial catalysts confirmed the feasibility of running in excess furfural. Both basic and acidic catalysts demonstrated significant activity, with CaO and amorphous silica-alumina achieving ≥80 mol% conversion of cyclopentanone and yielding ≥80 mol% selectivity towards the desired fuel components within 5 h of reaction. However, an overlooked aspect is the notable formation of undesired heavy side products. Observations indicated that the high furfural concentration, combined with the use of strong acidic catalysts, were the primary cause of heavy side product formation. The strong base catalyst, CaO, significantly reduced the formation of these oligomers, but did not appear to stop it completely. Interestingly, water content did not appear to play a major role in byproduct selectivity. To further suppress the formation of oligomers, the use of process-owned intermediates as solvents is proposed.

Technical efficiency and managerial ability in two-stage production processes with undesirable products: A case on Asian banks

Performance improvement and managerial ability estimation using benchmarking tools and data envelopment analysis (DEA) in banking and financial sectors have attracted considerable attention among researchers and bank managers. Although there are many efforts in two-stage DEA in banks, few studies have been conducted to measure managerial ability and technical efficiency of two-stage DEA in the banking sector. This contribution proposes a two-stage DEA procedure to estimate technical efficiency and managerial ability in the banking sector in six Asian countries. The empirical results obtained for selected Asian banks revealed that variables total capital adequacy ratio, total assets and number of branches have a positive impact on the efficiency of the deposit gathering section. Moreover, we observed that the number of ATMs has a negative impact on the efficiency of the sales and services section. Another finding is that in all these six countries, the sales and service section has performed better than the deposit gathering section.

Use of CO2 for enhanced carbon recovery in thermochemical processing of fruit peel waste

To address a supply variability associated with biomass, utilization of food waste provides a practical approach to consistently obtain carbon–neutral energy resource. Despite the technical merits of conventional biological process, the inevitable generation of less useful by-products, such as carbon dioxide (CO2) and sludge, remains a primary constraint. As an alternative, thermochemical process, such as pyrolysis, presents a promising solution for the comprehensive valorisation of food waste. In this study, citrus peel, one of the fruit processing wastes, was used as a model food waste. To enhance the eco-friendliness of the pyrolysis system, CO2 was introduced as a medium gas given the uncertainty regarding its behaviour as an inert or reactive agent at the pyrolysis temperatures. The pyrolysis approach demonstrated that CO2 interacts with volatile pyrogenic products, resulting in an increased formation of carbon monoxide (CO). Notably, this enhancement was observed at ≥ 400 °C, suggesting that CO2′s reactivity is limited at lower temperatures. To maximize the utility of CO2, the pyrolysis setup was modified by incorporating a heating block at 600 °C and a nickel-based catalyst (Ni/Al2O3). While these adjustments accelerated the thermal cracking of citrus peel, test setup modification led to an aromaticity increase of the resulting pyrogenic products. However, integrating CO2 into the catalytic pyrolysis created favourable conditions for detoxifying these aromatic compounds and further boosting CO production. Syngas productivity from catalytic pyrolysis in the presence of CO2 was 35.2 wt%, showing 3.67 times increase over that from conventional pyrolysis. In conclusion, CO2-assisted catalytic pyrolysis of the citrus peel offers significant technical benefits: it enhances carbon recovery in the form of CO and reduces the formation of undesirable aromatic pyrogenic products.

Regulation of Ir Dopant in Mo Oxides by Flame Spray Pyrolysis for Efficient CO2 Hydrogenation.

Mo carbide is recognized as one of the most promising catalysts for CO2 utilization via reverse water-gas shift (RWGS). However, the catalysts always suffered from low processing capacity, undesired products and deactivation. Herein, an Ir modified MoO3 synthesized by the flame spray pyrolysis (FSP) method exhibits higher reaction rate (63.0 gCO2 gcat -1 h-1) compared to the one made by traditional impregnation method (45.8 gCO2 gcat -1 h-1) over the RWGS reaction at 600 °C. The distinguishing feature between the two catalysts lies in the chemical state and space distribution of Ir species. Ir species predominated in the bulk phase of MoO3 during the quenching process of the FSP method and were mainly in the metallic states, which was revealed by X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectroscopy (ToF-SIMS) characterizations. In contrast, the Ir introduced via the impregnation method was mainly on the surface of MoO3 and in the oxidized state. The regulation of Ir dopant in MoO3 catalyst by different methods determines the carbonization process from MoO3 to Mo carbides and thus affects the catalytic performance over RWGS reaction. This work sheds light on the superiority of the FSP method in synthesizing Mo oxides with heteroatoms and further creating an efficient Mo-based catalyst for CO2 conversion.

Nitrate Reduction Catalyzed by Bimetallic Silver‐Copper Macroporous Foams

AbstractIn this work we describe the use of bimetallic silver‐copper macroporous foams for electrochemical nitrate reduction in acidic conditions (pH 2, 0.1 M NaClO4). By carefully selecting the composition of the electrodeposition bath, we have successfully prepared foams with atomic percentage varying from Ag dominant to Cu dominant. Also, we have succeeded to obtain morphologies that vary between the one specific to pure Ag foam to the one specific to pure Cu foam. We have shown that these foams contain a pure silver phase and also a silver‐copper alloy. The electrochemical active surface area of the foams depends both on the morphology as well as on the atomic composition. These materials were used for the first time as catalysts for nitrate electrochemical reaction (NO3RR). Both liquid and gaseous products were quantified with several analytical techniques. It was shown that bimetallic foams present superior faradaic efficiency (FE) towards liquid products in comparisons with pure silver and copper foams, suggesting a synergetic contribution from both metals. The Ag94Cu6 (AgCu10) foam shows a FE as high as 92 % towards liquid products and the lowest FE (3 %) towards the undesired product, i. e. nitrous acid. Also, this material shows a better stability than pure copper materials in the presence of nitrate in acidic conditions.

Study of Water Quality Parameters of Water Samples from Different Places Near Wani, Dist. Yavatmal

: Water is the essential source of life for all living forms and environmental health. All forms of life affected by water directly or indirectly. Water plays an important role in maintaining different activities in human life like metabolism, transport of nutrients, oxygen and wastes to cells and organs. Also it regulates body temperature. It also plays a significant role in prevention of some disease. Therefore water should be clean and free of contaminants to ensure wellness. Water bodies are contaminated by different manmade undesirable products which affects the nature of water. The present work is focused on assessment of water quality of samples through study of some physic-chemical parameters. The water samples are collected from four different locations around Wani area dist. Yavatmal. The comparative investigation of data has been done by correlation analysis of various parameters from different location samples. The results so obtained are interpreted in the light of pollution contamination status of the area and to know about the facts so that pollution control measures can be taken on time at various levels.

Unraveling the mechanistic interplay between CO and CO2 hydrogenation over Ni, Co, and NiCo catalysts

Although CO and CO2 hydrogenation reactions have been extensively studied, there is still significant controversy regarding the mechanism of methane formation and the routes for byproducts, especially when both carbon sources are simultaneously present. This work combines kinetic, operando-spectroscopic, isotopic techniques and DFT calculations to elucidate the relationships between CO and CO2 hydrogenation over mono Ni, Co and bimetallic NiCo catalysts with similar metal dispersion. The bimetallic catalysts showed a slight synergistic effect for methane formation from CO, while from CO2 the effect was opposite, showing a negative shift of activity as compared with those observed on the monometallic catalysts. The kinetic analysis shows similar apparent order with respect to H2 (∼0.5) and an inverse secondary isotope kinetic effect (<1) for both methanation reactions, suggesting that CH4 formation proceeds via C-O bond breaking in an H*-assisted mechanism, where the rate-determining step was not shown to be sensitive to the carbon source. The anti-synergistic effect observed on the bimetallic catalysts during CO2 hydrogenation is explained by the formation of unreactive HCOO* species (spectator), which generate a lower density of methane intermediates. On the other hand, the formation of the undesired products, i.e., CO or CO2 during CO2 or CO hydrogenation, respectively, shows relevant differences since the CO formation during CO2 hydrogenation proceeds through the desorption of the carbonyl species adsorbed on weak sites, meanwhile the CO2 formation from CO hydrogenation is due to a minority route of direct dissociation of CO, allowing the rejection of O* with CO* to produce CO2. This study contributes to elucidate the routes that determine the selectivity and reactivity for CO and CO2 hydrogenation and their mechanistic relationship. This information is valuable for the rational design and development of new materials with high performance during hydrogenation processes.

(Invited) Probing the Reaction Microenvironment during Electrochemical Nitrate Reduction to Ammonia

Nitrate pollution of wastewater from agricultural runoff and industrial waste streams is common around the globe. Nitrate negatively impacts the environment through harmful algal blooms and can be dangerous for human consumption. Strict limits have been set on nitrate discharge and the concentration in drinking water (< 50 ppm). Nitrate is currently removed from water by conversion to nitrogen through a biological process that requires chemical inputs (e.g., methanol) and post-treatment to remove biomass and organics.Electrochemical reduction of nitrate (NO3RR) to ammonia can remove nitrate from water and is an alternative to Haber-Bosch (HB) ammonia production, a significant source of global CO2 emissions. Ammonia is an important chemical precursor with potential applications in sustainable energy as a fuel or H2 carrier, or can be used as a fertilizer in the form of ammonium sulfate. This research addresses the water–energy nexus by converting nitrate to a valuable product, off-setting the cost of water treatment, and reducing demand for HB.NO3RR can be done from small to large scales, use renewable electricity, and eliminate the need for expensive and hazardous chemicals. However, NO3RR processes must exhibit selectivity toward ammonia to avoid the formation of other undesired products and occur at a low overpotential to minimize operating costs from electricity. To address these challenges, we must understand the reaction environment at the electrode–electrolyte interface, where heterogeneous electrochemical reactions occur. We use in situ attenuated total reflectance–surface-enhanced infrared adsorption spectroscopy (ATR–SEIRAS) to investigate the adsorbed reactants, intermediates, and interfacial pH. We studied the repeatability of the technique for in situ interfacial pH measurement and recommend controls to the community when using this method. The ATR–SEIRAS results are correlated with electrochemical experiments measuring NO3RR selectivity, activity, and efficiency. NO3RR products are measured by ion chromatography and gas chromatography. Our results relate bulk electrolyte properties with interfacial properties, and interfacial properties with reaction activity and selectivity. This understanding could lead to the development of electrolyte engineering strategies to optimize ammonia production in electrochemical NO3RR.

(Invited) Fundamentals of Single Atom Alloy Catalysts for Electrochemical Nitrate Reduction to Ammonia

Electrochemical conversion of toxic nitrate into useful ammonia provides a route to remediating the most frequent water pollutant while simultaneously generating one of the most produced bulk chemicals. While highly desirable, this conversion is plagued by complications including a highly branching reaction pathway - which can produce highly toxic undesirable products, the need to reduce a negatively charged species, a relatively low nitrate concentration, and competition for electrons between nitrate reduction and parasitic hydrogen evolution. Therefore, electrocatalysts must be developed which are highly selective not only for nitrate over other species in the water matrix, but also selective to the desired ammonia product. Single atom alloy catalysts, where a single atom of one element is embedded in a solvating phase of a secondary element, provides an opportunity to engineer catalysts with atomic level precision. In this presentation, we will outline the fundamental behavior of single atom alloy for nitrate reduction. We explore this topic through density functional theory calculations of the reaction mechanisms, including thermodynamics and kinetic aspects. Particularly, we will discuss the effect of single atom identity, effect of matrix element, and pH and potential. We show that the ability of the single atom to localize the N* species drives the reduction towards ammonia formation, as exemplified by Ru in Cu, while facile exchange of N* between the single atom site and the matrix leads to the formation of N2 or other undesirable products, as exemplified by Pd in Cu and Au in Cu, respectively. We also discuss the importance of the selection of the solvating element; for example, Cu is a good solvating metal because it is a good conductor, while minimizing the hydrogen evolution reaction. Further, we discuss the limits of pH and potential on the performance. In general, higher pH and more moderately negative potentials favor nitrate reduction to NH3 or N2, while lower pH and more negative potentials drive H2 evolution, and generation of NOx species.

Speciation and Diffusivity of Hydrogen in Molten 2LiF-BeF2 for Nuclear Fission and Fusion Applications

The behavior of hydrogen isotopes in molten 2LiF-BeF2 (FLiBe) is of interest to both advanced fission and fusion reactor designs. Tritium (hydrogen-3) is both a fission product and neutron activation product of lithium-6 fluoride in fission reactors which use FLiBe as a heat transfer fluid. In this case, tritium is an undesirable side product. In fusion reactors, FLiBe may be used as a blanket around the plasma which, upon neutron irradiation, generates tritium by the same neutron–Li-6 reaction. Here, tritium is a necessary and desirable product; the tritium is used to continuously fuel the deuterium-tritium fusion reaction. A thorough understanding of tritium’s behavior and residence time is relevant to managing tritium inventories in fission and fusion systems, which is essential for both the safety cases and functional operation of these reactors. Using hydrogen as a non-radioactive surrogate for tritium, we study the speciation and diffusivity of hydrogen in molten FLiBe at various temperatures relevant to reactor operating conditions.Here we present results of electrochemical investigations of hydrogen in FLiBe using cyclic and square wave voltammetry. We introduce hydrogen to FLiBe through 1) LiH additions and as 2) H2 gas, electrochemically desorbed from graphite. The expected solubility of H2 in FLiBe at 1 atm partial pressure is as low as 1 appm. Previous studies saw a higher apparent solubility of H2 at atmospheric pressure (up to 8000 appm). The possible presence of the postulated quasi-stable intermediate BeH2 is explored to explain the high apparent solubility of H2. The two methods of introducing H (as LiH reacting with BeF2 to form BeH2, which decomposes to H2, and the surface reduction of H2 on graphite) are compared to investigate the different species in which hydrogen may exist in molten FLiBe. Additionally, we attempt to quantify the diffusivity of these hydrogen species in FLiBe at 500ºC and 800ºC and compare findings with predicted diffusivities from computational models of Be and H additions to FLiBe. Overall, these studies seek to elucidate the speciation of hydrogen in FLiBe to aid in the management and operation of fission and fusion systems.

Environmental, economic and energy evaluation of alternative fuels for a steam power plant: Focus on biodiesel-nanoparticles utilization

Power plants are among the largest producers of GHGs. The fuel used in power plants is the main factor in the production of the emissions. Therefore, choosing a fuel that is environmentally optimal while being energy-efficient and economical is a key way to reduce GHG emissions. The addition of nanoparticles to biodiesel fuel not only improves the combustion efficiency of the fuel but also reduces the undesirable products. In this research, three supplementary fuels - fuel oil, diesel, and biodiesel-nanoparticles - are compared in terms of environmental, economic, and energy efficiency in a steam power plant. The changes in the power plant's self-consumption were measured by calculating the power consumption of the pump that delivers the fuel to the boiler. The results showed that diesel reduced the plant's efficiency by 0.00022 compared to using natural gas, which was the least of the other alternatives. The environmental analysis revealed that diesel produced the least amount of CO2 eq, but biodiesel-nanoparticle had a better CO2 footprint due to the higher absorption of CO2 in the cultivation phase of the raw material for biodiesel. The economic analysis for the fuels was carried out over ten years and based on the lifetime of the equipment purchased. Consequently, the total cost over the ten years for diesel was $967332.5161, which was $124475.8381 less than that for biodiesel-nanoparticle and $240935.3341 less than that for fuel oil. Finally, an overall comparison was made between the fuels using the AHP method. As the environmental criterion was the most important decision criterion, biodiesel-nanoparticle fuel was chosen with a marginal difference compared to diesel.