This study presents a comparative analysis of electricity, hydrogen, and biodiesel as energy vectors, with a focus on powering an aluminum smelter in southern Italy. It evaluates these vectors in terms of efficiency, ...This study presents a comparative analysis of electricity, hydrogen, and biodiesel as energy vectors, with a focus on powering an aluminum smelter in southern Italy. It evaluates these vectors in terms of efficiency, land requirements for carbon-neutral energy production, and capital expenditure, providing insights throughout the entire supply chain (upstream, midstream, and downstream) into their feasibility for industrial applications. The research reveals that biodiesel, despite being carbon neutral, is impractical due to extensive land requirements and lower efficiency if compared to other vectors. Hydrogen, downstream explored in two forms as thermal power generation and fuel cell technology, shows lower efficiency and higher capital expenditure compared to electricity. Additionally, green hydrogen production’s land requirements significantly exceed those of electricity-based systems. Electricity emerges as the most viable option, offering an overall higher efficiency, lower land requirements for its green production, and comparatively lower capital expenditure. The study’s findings highlight the importance of a holistic assessment of energy vectors, considering economic, environmental, and practical aspects along the entire energy supply chain, especially in industrial applications where the balance of these factors is crucial for long-term sustainability and feasibility. This comprehensive analysis provides valuable guidance for similar industrial applications, emphasizing the need for a balanced approach in the selection of energy vectors.展开更多
Climate change, mainly caused by the use of non-renewable fuels, has raised global concerns and led to the search for less polluting energy sources, making hydrogen a promising energy alternative with the potential to...Climate change, mainly caused by the use of non-renewable fuels, has raised global concerns and led to the search for less polluting energy sources, making hydrogen a promising energy alternative with the potential to contribute to changes in the energy mix of various countries through the use of technologies that enable its production and use with low or zero carbon emissions. In this context, Brazil has aroused great interest from other countries in exploring its renewable resources for the production of hydrogen (green hydrogen). In this sense, the use of natural gas pipelines and the use of hydrogen in mixtures with natural gas have become the subject of studies due to their economically viable alternative for the immediate use of this energy vector. However, there are still technical and regulatory challenges regarding the integration of hydrogen into the existing natural gas pipeline network. In this context, the present study aims to address the effects of hydrogen interaction with the structure of natural gas pipeline steel and the regulatory barriers to the use of this network for the transportation of green hydrogen, particularly in the state of Ceará/Brazil. After extensive analysis of literature and regulatory documents, it was concluded that: 1) Ceará/Brazil has strong potential to meet the demand for green hydrogen through the use of solar and wind energy sources;2) there is feasibility for the adaptation or conversion of natural gas infrastructure for the transportation of green hydrogen;3) discussions regarding the regulatory competence of green hydrogen transportation and distribution through the natural gas network in Brazil are still incipient;4) the current regulation of the natural gas industry can serve as a subsidy for the regulation of green hydrogen and natural gas transportation.展开更多
Global crises, notably climate shocks, degraded ecosystems, and growing energy demand, enforce sustainable production and consumption pathways. A circular bioeconomy offers the opportunities to actualize resource and ...Global crises, notably climate shocks, degraded ecosystems, and growing energy demand, enforce sustainable production and consumption pathways. A circular bioeconomy offers the opportunities to actualize resource and eco-efficiency enhancement, valorization of waste streams, reduction of fossil energy and greenhouse gas (GHG) emissions. Albeit biomass resources are a potential feedstock for bio-hydrogen (bio-H2) production, Ghana’s agricultural residues are not fully utilized. This paper examines the economic and environmental impact of bio-H2 electricity generation using agricultural residues in Ghana. The bio-H2 potential was determined based on biogas steam reforming (BSR). The research highlights that BSR could generate 2617 kt of bio-H2, corresponding to 2.78% of the global hydrogen demand. Yam and maize residues contribute 50.47% of the bio-H2 produced, while millet residues have the most negligible share. A tonne of residues could produce 16.59 kg of bio-H2 and 29.83 kWh of electricity. A total of 4,705.89 GWh of electricity produced could replace the consumption of 21.92% of Ghana’s electricity. The economic viability reveals that electricity cost is $0.174/kWh and has a positive net present value of $2135550609.45 with a benefit-to-cost ratio of 1.26. The fossil diesel displaced is 1421.09 ML, and 3862.55 kt CO2eq of carbon emissions decreased corresponding to an annual reduction potential of 386.26 kt CO2eq. This accounts for reducing 10.26% of Ghana’s GHG emissions. The study demonstrates that hydrogen-based electricity production as an energy transition is a strategic innovation pillar to advance the circular bioeconomy and achieve sustainable development goals.展开更多
An efficient and safe hydrogen storage method is one of the important links for the large-scale development of hydrogen in the future. Because of its low price and simple design, Ti-based hydrogen storage alloys are c...An efficient and safe hydrogen storage method is one of the important links for the large-scale development of hydrogen in the future. Because of its low price and simple design, Ti-based hydrogen storage alloys are considered to be suitable for practical applications. In this paper, we review the latest research on Ti-based hydrogen storage alloys. Firstly, the machine learning and density functional theory are introduced to provide theoretical guidance for the optimization of Ti-based hydrogen storage alloys. Then, in order to improve the hydrogen storage performance, we briefly introduce the research of AB type and AB2 type Ti-based alloys, focusing on doping elements and adaptive after treatment. Finally, suggestions for the future research and development of Ti-based hydrogen storage alloys are proposed. .展开更多
Preferably 20 ppm anhydrous ammonia (NH<sub>3</sub>) is proposed to be added to hydrogen fuel (H) made from renewable energy sources (green hydrogen), so that H leaks may be easily detectable by smell, but...Preferably 20 ppm anhydrous ammonia (NH<sub>3</sub>) is proposed to be added to hydrogen fuel (H) made from renewable energy sources (green hydrogen), so that H leaks may be easily detectable by smell, but not dangerously toxic. Including this odor agent, would allow H to be distributed safely in pipes, as required by law, and it would allow H to be safely stored, transported, and exported for sale, and widely commercialized. Further research is suggested to identify optimum pressure, temperature, and automated technique for injecting NH<sub>3</sub> into H, and to chart the minimum concentration needed, as a function of temperature and humidity. An application to make hypersonic H burning aircraft safer for ground maintenance crews is proposed. An ability to make, store and distribute H, made from local sources of renewable energy, would reduce a need for fossil fuels, especially in poor, remote communities, where it could improve their economy by creating an export product for sale, while reducing pollution.展开更多
Hydrogen energy as a sustainable energy source has most recently become an increasingly important renewable energy resource due to its ability to power fuel cells in zero-emission vehicles and its help in lowering the...Hydrogen energy as a sustainable energy source has most recently become an increasingly important renewable energy resource due to its ability to power fuel cells in zero-emission vehicles and its help in lowering the levels of CO2</sub> emissions. Also, hydrogen has a high energy density and can be utilized in a wide range of applications. It is indeed the fuel of the future but, it is still not entirely apparent how to analyze the most successful ways for hydrogen storage based on technological configuration, nature, and efficiency mechanisms. The historical hydrogen storage technologies as they are presented by the current research have been evaluated, analyzed, and examined in this study. The two categories of hydrogen storage systems are physical-based and material-based.The first category involves storing hydrogen as liquid, cold/cryo-compressed, and compressed gas. Chemical sorption/chemisorption and physical sorption/physisorption are the two primary sub-groups of material-based storage, respectively. The quantitative and qualitative analyses of storage technologies for hydrogen are evaluated in this paper. Also, this report reviews the major safety and reliability issues currently facing hydrogen storage systems. Suggestions are made to assist lay the groundwork for future risk and reliability analysis to ensure safe, dependable operation.展开更多
Seborrheic keratosis has a varying degree of pigmentation. In pigmented seborrheic keratosis, the proliferating keratinocytes trigger the activation of neighboring melanocytes by secreting melanocyte-stimulating cytok...Seborrheic keratosis has a varying degree of pigmentation. In pigmented seborrheic keratosis, the proliferating keratinocytes trigger the activation of neighboring melanocytes by secreting melanocyte-stimulating cytokines. The etiology of seborrheic keratosis is not known. Epidermal growth factors or their receptors have been implicated in the development of seborrheic keratosis. Seborrheic keratoses can safely be left alone, but ugly or easily traumatized ones can be removed with cryotherapy, electrodesiccation, curettage, or shave excision. The present work aims to compare two modalities of treatment for seborrheic keratosis, namely cryotherapy and hydrogen peroxide (30%). Methods: 30 patients with seborrheic keratosis were included in this study. They were divided into two groups, each with 15 patients. The treatment modalities that have been used include cryotherapy and hydrogen peroxide in three different concentrations (30%, 35%, and 40%). Result: The cryotherapy group consisted of 15 patients, 7 males and 8 females. Their ages ranged from 38 to 80 years, with a mean of 56.1 ± 11.4. Clinical and photographic assessments showed complete removal in all 15 patients in this group (100%). As regards the hydrogen peroxide group, this group included 15 patients, distributed among 7 males and 8 females. Their ages ranged from 39 to 90 years, with a mean of 53.9 ± 14.4. Clinical and photographic assessments showed response in only one small superficial lesion in one patient (6.7%) and no response in 14 patients (93.3%). Conclusion: Cryotherapy is an effective, easy, and relatively cheap method for treating seborrheic keratosis.展开更多
Double differential cross-sections of first Born estimation for ionization of hydrogenic 2S state by electrons are assessed for various kinematics situations in the asymmetric coplanar geometry. A final state wave fun...Double differential cross-sections of first Born estimation for ionization of hydrogenic 2S state by electrons are assessed for various kinematics situations in the asymmetric coplanar geometry. A final state wave function of multiple scattering theory is followed in this study. The present outcomes are compared with those of hydrogenic ground state, 2P state and ground state experimental results. Obtained findings show a good qualitative agreement with existing results.展开更多
Nitriding of the surface in martensitic stainless steels is commonly carried out to improve their wear resistance. The process of plasma nitriding in stainless steel is influenced by two mechanisms: physical diffusion...Nitriding of the surface in martensitic stainless steels is commonly carried out to improve their wear resistance. The process of plasma nitriding in stainless steel is influenced by two mechanisms: physical diffusion through the surface and chemical gas-metal reaction. The inner nitriding interaction involves the simultaneous penetration and formation of a solid solution, as well as the interaction of nitrogen with specific alloying elements, resulting in the development of homogeneous and heterogeneous structures. Our study concludes that the observed intergranular hydrogen embrittlement and crack formation during the surface nitridation process of AMS 5719 martensite alloy steel can be attributed to the ammonium concentration of approximately 50% at a temperature of 530˚C.展开更多
The catalytic hydrogenation of D-glucose over a 3 wt% Ru/C catalyst was studied varying the operating conditions in mild conditions range to optimize the obtention of D-sorbitol. The stirring speed, temperature, press...The catalytic hydrogenation of D-glucose over a 3 wt% Ru/C catalyst was studied varying the operating conditions in mild conditions range to optimize the obtention of D-sorbitol. The stirring speed, temperature, pressure, and initial glucose concentration were varied between 250 - 700 rpm, 343 - 383 K, 0.5 - 2 MPa, and 0.033 - 0.133 M, respectively. To verify the absence of mass transport limitations, the diffusion of reagents in the gas-liquid interface, the liquid-solid interface, and the internal diffusion in the particles were evaluated. Under the operating conditions studied, the reaction rate showed an order with respect to H<sub>2</sub> of 0.586 and with respect to glucose of 0.406. The kinetic data were adjusted using 3 general models and 19 different sub-models based on Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetics. Model 3a was the best one interpreting the aqueous phase hydrogenation of glucose (both reagents competitively adsorbed on the catalyst). The H<sub>2</sub> adsorption is dissociative and the rate-limiting step is the surface chemical reaction.展开更多
文摘This study presents a comparative analysis of electricity, hydrogen, and biodiesel as energy vectors, with a focus on powering an aluminum smelter in southern Italy. It evaluates these vectors in terms of efficiency, land requirements for carbon-neutral energy production, and capital expenditure, providing insights throughout the entire supply chain (upstream, midstream, and downstream) into their feasibility for industrial applications. The research reveals that biodiesel, despite being carbon neutral, is impractical due to extensive land requirements and lower efficiency if compared to other vectors. Hydrogen, downstream explored in two forms as thermal power generation and fuel cell technology, shows lower efficiency and higher capital expenditure compared to electricity. Additionally, green hydrogen production’s land requirements significantly exceed those of electricity-based systems. Electricity emerges as the most viable option, offering an overall higher efficiency, lower land requirements for its green production, and comparatively lower capital expenditure. The study’s findings highlight the importance of a holistic assessment of energy vectors, considering economic, environmental, and practical aspects along the entire energy supply chain, especially in industrial applications where the balance of these factors is crucial for long-term sustainability and feasibility. This comprehensive analysis provides valuable guidance for similar industrial applications, emphasizing the need for a balanced approach in the selection of energy vectors.
文摘Climate change, mainly caused by the use of non-renewable fuels, has raised global concerns and led to the search for less polluting energy sources, making hydrogen a promising energy alternative with the potential to contribute to changes in the energy mix of various countries through the use of technologies that enable its production and use with low or zero carbon emissions. In this context, Brazil has aroused great interest from other countries in exploring its renewable resources for the production of hydrogen (green hydrogen). In this sense, the use of natural gas pipelines and the use of hydrogen in mixtures with natural gas have become the subject of studies due to their economically viable alternative for the immediate use of this energy vector. However, there are still technical and regulatory challenges regarding the integration of hydrogen into the existing natural gas pipeline network. In this context, the present study aims to address the effects of hydrogen interaction with the structure of natural gas pipeline steel and the regulatory barriers to the use of this network for the transportation of green hydrogen, particularly in the state of Ceará/Brazil. After extensive analysis of literature and regulatory documents, it was concluded that: 1) Ceará/Brazil has strong potential to meet the demand for green hydrogen through the use of solar and wind energy sources;2) there is feasibility for the adaptation or conversion of natural gas infrastructure for the transportation of green hydrogen;3) discussions regarding the regulatory competence of green hydrogen transportation and distribution through the natural gas network in Brazil are still incipient;4) the current regulation of the natural gas industry can serve as a subsidy for the regulation of green hydrogen and natural gas transportation.
文摘Global crises, notably climate shocks, degraded ecosystems, and growing energy demand, enforce sustainable production and consumption pathways. A circular bioeconomy offers the opportunities to actualize resource and eco-efficiency enhancement, valorization of waste streams, reduction of fossil energy and greenhouse gas (GHG) emissions. Albeit biomass resources are a potential feedstock for bio-hydrogen (bio-H2) production, Ghana’s agricultural residues are not fully utilized. This paper examines the economic and environmental impact of bio-H2 electricity generation using agricultural residues in Ghana. The bio-H2 potential was determined based on biogas steam reforming (BSR). The research highlights that BSR could generate 2617 kt of bio-H2, corresponding to 2.78% of the global hydrogen demand. Yam and maize residues contribute 50.47% of the bio-H2 produced, while millet residues have the most negligible share. A tonne of residues could produce 16.59 kg of bio-H2 and 29.83 kWh of electricity. A total of 4,705.89 GWh of electricity produced could replace the consumption of 21.92% of Ghana’s electricity. The economic viability reveals that electricity cost is $0.174/kWh and has a positive net present value of $2135550609.45 with a benefit-to-cost ratio of 1.26. The fossil diesel displaced is 1421.09 ML, and 3862.55 kt CO2eq of carbon emissions decreased corresponding to an annual reduction potential of 386.26 kt CO2eq. This accounts for reducing 10.26% of Ghana’s GHG emissions. The study demonstrates that hydrogen-based electricity production as an energy transition is a strategic innovation pillar to advance the circular bioeconomy and achieve sustainable development goals.
文摘An efficient and safe hydrogen storage method is one of the important links for the large-scale development of hydrogen in the future. Because of its low price and simple design, Ti-based hydrogen storage alloys are considered to be suitable for practical applications. In this paper, we review the latest research on Ti-based hydrogen storage alloys. Firstly, the machine learning and density functional theory are introduced to provide theoretical guidance for the optimization of Ti-based hydrogen storage alloys. Then, in order to improve the hydrogen storage performance, we briefly introduce the research of AB type and AB2 type Ti-based alloys, focusing on doping elements and adaptive after treatment. Finally, suggestions for the future research and development of Ti-based hydrogen storage alloys are proposed. .
文摘Preferably 20 ppm anhydrous ammonia (NH<sub>3</sub>) is proposed to be added to hydrogen fuel (H) made from renewable energy sources (green hydrogen), so that H leaks may be easily detectable by smell, but not dangerously toxic. Including this odor agent, would allow H to be distributed safely in pipes, as required by law, and it would allow H to be safely stored, transported, and exported for sale, and widely commercialized. Further research is suggested to identify optimum pressure, temperature, and automated technique for injecting NH<sub>3</sub> into H, and to chart the minimum concentration needed, as a function of temperature and humidity. An application to make hypersonic H burning aircraft safer for ground maintenance crews is proposed. An ability to make, store and distribute H, made from local sources of renewable energy, would reduce a need for fossil fuels, especially in poor, remote communities, where it could improve their economy by creating an export product for sale, while reducing pollution.
文摘Hydrogen energy as a sustainable energy source has most recently become an increasingly important renewable energy resource due to its ability to power fuel cells in zero-emission vehicles and its help in lowering the levels of CO2</sub> emissions. Also, hydrogen has a high energy density and can be utilized in a wide range of applications. It is indeed the fuel of the future but, it is still not entirely apparent how to analyze the most successful ways for hydrogen storage based on technological configuration, nature, and efficiency mechanisms. The historical hydrogen storage technologies as they are presented by the current research have been evaluated, analyzed, and examined in this study. The two categories of hydrogen storage systems are physical-based and material-based.The first category involves storing hydrogen as liquid, cold/cryo-compressed, and compressed gas. Chemical sorption/chemisorption and physical sorption/physisorption are the two primary sub-groups of material-based storage, respectively. The quantitative and qualitative analyses of storage technologies for hydrogen are evaluated in this paper. Also, this report reviews the major safety and reliability issues currently facing hydrogen storage systems. Suggestions are made to assist lay the groundwork for future risk and reliability analysis to ensure safe, dependable operation.
文摘Seborrheic keratosis has a varying degree of pigmentation. In pigmented seborrheic keratosis, the proliferating keratinocytes trigger the activation of neighboring melanocytes by secreting melanocyte-stimulating cytokines. The etiology of seborrheic keratosis is not known. Epidermal growth factors or their receptors have been implicated in the development of seborrheic keratosis. Seborrheic keratoses can safely be left alone, but ugly or easily traumatized ones can be removed with cryotherapy, electrodesiccation, curettage, or shave excision. The present work aims to compare two modalities of treatment for seborrheic keratosis, namely cryotherapy and hydrogen peroxide (30%). Methods: 30 patients with seborrheic keratosis were included in this study. They were divided into two groups, each with 15 patients. The treatment modalities that have been used include cryotherapy and hydrogen peroxide in three different concentrations (30%, 35%, and 40%). Result: The cryotherapy group consisted of 15 patients, 7 males and 8 females. Their ages ranged from 38 to 80 years, with a mean of 56.1 ± 11.4. Clinical and photographic assessments showed complete removal in all 15 patients in this group (100%). As regards the hydrogen peroxide group, this group included 15 patients, distributed among 7 males and 8 females. Their ages ranged from 39 to 90 years, with a mean of 53.9 ± 14.4. Clinical and photographic assessments showed response in only one small superficial lesion in one patient (6.7%) and no response in 14 patients (93.3%). Conclusion: Cryotherapy is an effective, easy, and relatively cheap method for treating seborrheic keratosis.
文摘Double differential cross-sections of first Born estimation for ionization of hydrogenic 2S state by electrons are assessed for various kinematics situations in the asymmetric coplanar geometry. A final state wave function of multiple scattering theory is followed in this study. The present outcomes are compared with those of hydrogenic ground state, 2P state and ground state experimental results. Obtained findings show a good qualitative agreement with existing results.
文摘Nitriding of the surface in martensitic stainless steels is commonly carried out to improve their wear resistance. The process of plasma nitriding in stainless steel is influenced by two mechanisms: physical diffusion through the surface and chemical gas-metal reaction. The inner nitriding interaction involves the simultaneous penetration and formation of a solid solution, as well as the interaction of nitrogen with specific alloying elements, resulting in the development of homogeneous and heterogeneous structures. Our study concludes that the observed intergranular hydrogen embrittlement and crack formation during the surface nitridation process of AMS 5719 martensite alloy steel can be attributed to the ammonium concentration of approximately 50% at a temperature of 530˚C.
文摘The catalytic hydrogenation of D-glucose over a 3 wt% Ru/C catalyst was studied varying the operating conditions in mild conditions range to optimize the obtention of D-sorbitol. The stirring speed, temperature, pressure, and initial glucose concentration were varied between 250 - 700 rpm, 343 - 383 K, 0.5 - 2 MPa, and 0.033 - 0.133 M, respectively. To verify the absence of mass transport limitations, the diffusion of reagents in the gas-liquid interface, the liquid-solid interface, and the internal diffusion in the particles were evaluated. Under the operating conditions studied, the reaction rate showed an order with respect to H<sub>2</sub> of 0.586 and with respect to glucose of 0.406. The kinetic data were adjusted using 3 general models and 19 different sub-models based on Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetics. Model 3a was the best one interpreting the aqueous phase hydrogenation of glucose (both reagents competitively adsorbed on the catalyst). The H<sub>2</sub> adsorption is dissociative and the rate-limiting step is the surface chemical reaction.
