Search

Beige fat activation involves a fuel switch to fatty acid oxidation following chronic cold adaptation. Mitochondrial acyl-CoA synthetase long-chain family member 1 (ACSL1) localizes in the mitochondria and plays a key role in fatty acid oxidation; however, the regulatory mechanism of the subcellular localization remains poorly understood. Here, we identify an endosomal trafficking component sortilin (encoded by Sort1) in adipose tissues that shows dynamic expression during beige fat activation and facilitates the translocation of ACSL1 from the mitochondria to the endolysosomal pathway for degradation. Depletion of sortilin in adipocytes results in an increase of mitochondrial ACSL1 and the activation of AMPK/PGC1α signaling, thereby activating beige fat and preventing high-fat diet (HFD)-induced obesity and insulin resistance. Collectively, our findings indicate that sortilin controls adipose tissue fatty acid oxidation by substrate fuel selection during beige fat activation and provides a potential targeted approach for the treatment of metabolic diseases. Beige fat activation involves a fuel switch to fatty acid oxidation following chronic cold adaptation. Here, the authors show that Sortilin in adipose tissues facilitates the translocation of ACSL1 from the mitochondria to the endolysosomal pathway for degradation, which controls adipose tissue fatty acid oxidation and substrate fuel selection during beige fat activation. [ABSTRACT FROM AUTHOR]

Energy poverty has been a major concern for sub-Saharan Africa (SSA). Government efforts predominantly focus on expanding national grid networks to address energy needs. Less attention has been given to alternative forms of co-provision of cooking and lighting energy, although they are critical elements of urban energy governance. Using the analytical concept of socio-technical heterogeneity, this study draws insights from empirical data in Accra to understand everyday energy configurations used by urban dwellers outside the formal state-led infrastructures. It was found that, for electricity, households adopt heterogeneous configurations, including electricity theft, meter sharing, illegal expansion of the grid, self-help solar PV, use of small diesel generators, back-up power appliances, and service phone charging vendors. In terms of cooking energy, households adopt fuel switching, use of multiple cooking stoves, and use of improved cooking stoves. These co-provisions reflect a governance failure and, at the same time, fill critical provision gaps. Heterogeneous configurations also come with socioeconomic and environmental externalities. The findings suggest a need for decentralisation and integration of context-specific, place-based and situated forms of co-provision or heterogeneous configuration into urban energy planning and governance. [ABSTRACT FROM AUTHOR]

Fuel switching is the most mature, reliable, and economical technology for ship operators to comply with regulations of sulfur emission control area (SECA), and will remain so for the next few years. Under SECA regulations, this paper tries to optimize liner shipping operation by integrating ship deployment, schedule design, and speed optimization while considering transit time. Specifically, a mixed integer nonlinear programming model was built to minimize operating costs, and fully guarantee the logic and superiority of the existing liner shipping network. A two-stage algorithm based on ɛ outer approximation estimation and enumeration was designed, and a backtracking algorithm was provided for determining initial port combinations in large-scale instances. After that, a case study on the Orient Overseas Container Line was carried out to verify the operability and flexibility of our method. The optimized strategy refines the existing network by adjusting initial port combinations, enhancing speed, and expanding new ship deployments. To mitigate the impact of rising port demurrage fees, liner companies are reducing transshipment penalty costs. While easing connecting time window (CTW) restrictions offers limited benefits, optimizing speed and loosening CTW can reduce operational costs by approximately 2–5%, helping liner companies navigate the fluctuating fuel market post-Covid. [ABSTRACT FROM AUTHOR]

Decoupling of production activities and greenhouse gas (GHG) emissions, or a decline in GHG intensity, is a key metric for gauging GHG mitigation performances. In this study, we explore the determinants of GHG intensity in Canadian industries to understand its key drivers. This study is relevant, because Canada is a developed country characterized by high energy and GHG intensities. Canada has also introduced a series of policy measures to mitigate GHG emissions, including a carbon tax and investments in renewable electricity. The most significant factor for GHG intensity is energy intensity. However, fuel mix, policy trends, and sectoral shifts are essential. After conducting stationarity and cointegration tests, we estimated the relationship between GHG intensity and these determinants using panel error correction, dynamic fixed effects, and dynamic OLS methods to determine the long-run relationships. Besides the strong effect of energy intensity, we found that industrial production mix that indicates sectoral shifts, fuel mix, and the time-fixed effects that capture factors such as the introduction of a carbon tax and technology standards have statistically significant impacts on GHG intensity. We found that industries that rely more on fuel sources other than electricity are characterized by higher GHG intensity. The policy implication is that energy efficiency and fuel switching are essential for reducing GHG intensity, but the role of factors such as sectoral shifts should not be ignored. [ABSTRACT FROM AUTHOR]

The present case study considers fuel base substitution in operation of actual district heating system and in other scenario replacing of district heating system by individual heating system in each apartment building and non-residential building in selected residential zone Zvolen-Sekier, Slovakia. The impact of each heating system was assessed with focus on ambient air quality based on air dispersion modelling of NO2 and CO pollutans using the AERMOD dispersion model. To identify the exposure level on residents, the magnitude and duration of exposure to the hazard were considered according to human health risk assessment method. Results showed that the individual heating systems released significantly higher NO2 and CO concentrations directly in the residential zone compared to district heating system. The obtained results were highly variable for individual scenarios and averaged periods of pollutants concentration. Investigated heating systems scenarios showed low (< 1.0) hazard quotient value, however, individual heating systems would lead to adverse health effects, especially in infants and children population. [ABSTRACT FROM AUTHOR]

Firefighters' or instructors' exposure to airborne chemicals during live-fire training may depend on fuels being burned, fuel orientation and participants' location within the structure. This study was designed to evaluate the impact of different control measures on exposure risk to combustion byproducts during fire dynamics training where fuel packages are mounted at or near the ceiling. These measures included substitution of training fuels (low density wood fiberboard, oriented strand board (OSB), pallets, particle board, plywood) and adoption of engineering controls such as changing the location of the instructor and students using the structure. Experiments were conducted for two different training durations: the typical six ventilation cycle (six-cycle) and a shorter three ventilation cycle (three-cycle) with a subset of training fuels. In Part A of this series, we characterized the fire dynamics within the structure, including the ability of each fuel to provide an environment that achieves the training objectives. Here, in Part B, airborne chemical concentrations are reported at the location where fire instructors would typically be operating. We hypothesized that utilizing a training fuel package with solid wood pallets would result in lower concentrations of airborne contaminants at the rear instructor location than wood-based sheet products containing additional resins and/or waxes. In the six-cycle experiments (at the rear instructor location), OSB-fueled fires produced the highest median concentrations of benzene and 1,3 butadiene, plywood-fueled fires produced the highest total polycyclic aromatic hydrocarbon (PAH) concentrations, particle board-fueled fires produced the highest methyl isocyanate concentrations, and pallet-fueled fires produced the highest hydrogen chloride concentrations. All fuels other than particle board produced similarly high levels of formaldehyde at the rear instructor location. The OSB fuel package created the most consistent fire dynamics over six-cycles, while fiberboard resulted in consistent fire dynamics only for the first three cycles. In the follow-on three-cycle experiment, PAH, benzene, and aldehyde concentrations were similar for the OSB and fiberboard-fueled fires. Air sampling did not identify any clear differences between training fires from burning solid wood pallets and those that incorporate wood-based sheet products for this commonly employed fuel arrangement with fuels mounted high in the compartment. However, it was found that exposure can be reduced by moving firefighters and instructors lower in the compartment and/or by moving the instructor in charge of ventilation from the rear of the structure (where highest concentrations were consistently measured) to an outside position. [ABSTRACT FROM AUTHOR]

The use of hydrogen can be a potential solution to reduce high CO and unburnt HC emissions, which is one of the most critical challenges, from Reactivity Controlled Compression Ignition (RCCI) engines at low loads as it is a very clean and carbon-free fuel candidate for internal combustion engines. Therefore, the aim of this study is designed to investigate numerically the effect of the hydrogen share on combustion characteristics in a diesel research engine operated in RCCI mode. The engine is fueled with conventional diesel and iso-octane enriched with hydrogen and is operated at 20% of the maximum torque (low load) and 2400 rpm. A 40% of conventional diesel (in the case of conventional diesel mode (CDM), its share was 100%) is injected per cycle into cylinder of the engine, while varying proportions of iso-octane (60% to 12%) and hydrogen (0% to 48%) are sprayed into the air from the intake manifold. Both CDM and RCCI combustion models built by 3D scanning of the existing engine using reverse engineering to computational fluid dynamic (CFD) was simulated through ANSYS-Forte coupled with a chemical kinetics solver (Chemkin-Pro). The simulation results showed that by adding hydrogen to iso-octane in RCCI mode, the proportion of hydrogen could be increased up to 48% while improving thermal efficiency by 33.3% in comparison with 24.9% with RCCI without hydrogen addition. Therefore, the overall hydrocarbon fuel consumption per cycle was reduced by up to 47.52%. Hydrogen addition resulted in a higher concentration of OH species in the flame front, and higher pressure and temperature in the cylinder, in turn, contributed to an increase in NOx emissions considerably but led to decrease in CO/HC emissions of RCCI operation. The decrease in the emissions of CO, HC, and C2H2 of up to 64.6, 81.8, and 76.6%, respectively, was observed by using 48% of H2 in RCCI mode compared to RCCI mode without hydrogen addition. It was concluded that high CO and unburned HC emissions from RCCI combustion. This research provides promising contributions to the literature for using hydrogen in substitution of hydrocarbon fuels and reducing emissions from RCCI engines. [ABSTRACT FROM AUTHOR]

Various shipping emissions controls have recently been implemented at both local and national scales. However, it is difficult to track the effect of these on PM2.5 levels, owing to the non-linear relationship that exists between changes in precursor emissions and PM components. Positive Matrix Factorisation (PMF) identifies that a switch to cleaner fuels since January 2020 results in considerable reductions in shipping-source-related PM2.5, especially sulphate aerosols and metals (V and Ni), not only at a port site but also at an urban background site. CMAQ sensitivity analysis reveals that the reduction of secondary inorganic aerosols (SIA) further extends to inland areas downwind from ports. In addition, mitigation of secondary organic aerosols (SOA) in coastal urban areas can be anticipated either from the results of receptor modelling or from CMAQ simulations. The results in this study show the possibility of obtaining human health benefits in coastal cities through shipping emission controls. [ABSTRACT FROM AUTHOR]

Addressing inequality is recognized a worldwide development objective. The literature has primarily focused on examining economic or social inequality, but rarely on environmental inequality. Centering the discussion on economic or social factors does not provide a holistic view of inequality because it is multidimensional and several facets may overlap imposing a disproportionate burden on vulnerable communities. This study investigates the magnitude of air quality inequality in conjunction with economic and social inequalities in Bogotá (Colombia). It explores where inequalities overlap and assesses alleviation measures by tackling air pollution. We develop a composite index to estimate performance in socioeconomic and air quality characteristics across the city and evaluate inequality with a variety of measures. Using an atmospheric chemical transport model, we simulate the impact of three air pollution abatement policies: paving roads, industry fuel substitution, and diesel-vehicle renewal on fine particle concentrations, and compute their effect on inequality. Results show that allocation of air quality across Bogotá is highly unequal, exceeding economic or social inequality. Evidence also indicates that economic, social and air quality disparities intersect, displaying the southwest as the most vulnerable zone. Paving roads is found to be the most progressive and cost-effective policy, reducing overall inequality between 11 and 46 percent with net benefits exceeding US$1.4 billion. [ABSTRACT FROM AUTHOR]

Energy conservation associated with hibernation is maximized at the intersection of low body temperature (Tb), long torpor bouts, and few interbout arousals. In the arctic ground squirrel (Urocitellus parryii), energy conservation during hibernation is best achieved at ambient temperatures (Ta) around 0 °C; however, they spend the majority of hibernation at considerably lower Ta. Because arctic ground squirrels switch to mixed fuel metabolism, including protein catabolism, at extreme low Ta of hibernation, we sought to investigate how microbial urea-nitrogen recycling is used under different thermal conditions. Injecting squirrels with isotopically labeled urea (13C/15N) during hibernation at Ta’s of − 16 °C and 2 °C and while active and euthermic allowed us to assess the ureolytic activity of gut microbes and the amount of liberated nitrogen incorporated into tissues. We found greater incorporation of microbially-liberated nitrogen into tissues of hibernating squirrels. Although ureolytic activity appears higher in euthermic squirrels, liberated nitrogen likely makes up a smaller percentage of the available nitrogen pool in active, fed animals. Because non-lipid fuel is a limiting factor for torpor at lower Ta in this species, we hypothesized there would be greater incorporation of liberated nitrogen in animals hibernating at − 16 °C. However, we found higher microbial-ureolytic activity and incorporation of microbially-liberated nitrogen, particularly in the liver, in squirrels hibernating at 2 °C. Likely this is because squirrels hibernating at 2 °C had higher Tb and longer interbout arousals, a combination of factors creating more favorable conditions for gut microbes to thrive and maintain greater activity while giving the host more time to absorb microbial metabolites. [ABSTRACT FROM AUTHOR]

This study estimates agricultural residue biomass available for biogas generation in smallholder farming systems in the rural Vakinankaratra region of Madagascar, during 2017–2018. Estimations of biomass were done using a combination of agricultural household surveys, literature models, and publicly available data. Manure from four types of farm animals and 17 residue types from ten crops were assessed. In the studied period, gross biomass produced from animal manure and crop residue were 19.4 ± 7.41 and 7.3 ± 1.08 tonnes fresh weight per year per agricultural household, respectively, of which up to 54% and 83% are estimated as recoverable for the production of bioenergy in the studied area, respectively. Estimations indicate that available animal manure and crop residue have the potential to generate 291 ± 92 and 745 ± 122 Nm3 of methane per year per agricultural household respectively, equivalent to 10.5 ± 3.34 and 26.8 ± 4.28 GJ of heat energy from manure and residues, respectively. Theoretically, the average estimated energy potential can result in the complete substitution of domestic fuels in agricultural households. Approximately 0.12 tonnes of nitrogen per household per year can be recovered from the estimated digestate (using all residue types) after energy recovery, which can be employed for crop fertilization. The recovered nitrogen corresponds to 0.26 tonnes urea fertilizer per household per year. The investigation shows that anaerobic digestion based on crop residue and manure has the potential to meet a significant portion of energy needs of smallholder farmers in the Vakinankaratra region of Madagascar and can make an important contribution to providing fertilizer for on-farm use. [ABSTRACT FROM AUTHOR]

The negative health effects of cement plant exposure are well-known in industrial settings, but they are less well-known among the general public who live near plants. The broad objective of the review was to provide a detailed systematic analysis of the global situation of the cement industry, including generation, pollution, impact on the natural ecosystem, technological and process improvements, sustainable models, the latest laws, challenges, needs, and ways forward. As an initial evaluation, a list of critical keywords was compiled, and a search of all accessible databases was conducted (i.e., Scopus, Web of Knowledge, Google Scholar). The manuscripts published in the journal between 2011 and 2021 were included. According to the findings, India is the second largest cement producer after China, with an installed capacity of 537 million tonnes and around 7.1 percent of the world's production, up from 337.32 million tonnes in 2019. NOx, SOx, CO, CO2, H2S, VOCs, dioxins, furans, and particulate matter are all common air pollutants from cement manufacturing. Other sources of dust particles include quarrying, blasting, drilling, trucking, cement plants, fuel production, packaging, path cleaning, and slabs. Other methods of reduction play an important part in decreasing industrial emissions, resulting in lower carbon and more sustainable products. The decision-making trial, in conjunction with the DEMATEL evaluation laboratory and the analytical hierarchy process (AHP) technique, will aid in determining the priority of climate alteration and mitigation options. Furthermore, employing sustainable techniques and technology, switching to alternative fuels will save 12% of total CO2 emissions by 2050. [ABSTRACT FROM AUTHOR]

The electrical power of a thermionic reactor-converter is determined by various parameters of the thermionic fuel element and reactor core, as well as by the formation of the electrical branch that connects thermionic fuel elements according to various criteria. The formation of electric branches is possible in various ways. The number of branches is determined by the specified characteristics of the thermionic fuel element and the required electrical power. In this case, the thermionic fuel elements are connected electrically in series to the branches, and the branches themselves are connected in parallel. The selection of the electrical branch in the core of the reactor is based on the characteristics of each thermionic fuel element. In this article, we evaluate the characteristics of the thermionic reactor-converter with various options for switching thermionic fuel elements. [ABSTRACT FROM AUTHOR]

The aim of this article is to analyse the current situation of access to energy (in relation to SDG 7) and energy usage behaviour in households in two provinces in Cambodia, namely Pursat and Kampong Cham. The analytical framework is based on the energy ladder model and the energy stacking model as a starting point for assessing the current household energy profiles. A quantitative survey carried out in late 2015 in 970 households revealed differences in access to electricity between urban, electrified rural, and non-electrified rural districts. In urban areas, households are using multiple (3–4) energy sources compared to rural areas (2–3). The use of electricity through batteries in the non-electrified rural areas remains notable (43%) despite no access to the national grid. The dependence on traditional biomass, especially firewood, remains high (91% of all respondents) for all the sampled households, especially so in rural non-electrified households. The study confirms that households' energy mix is composed of various energy sources, even when modern energy sources are available as opposed to complete fuel switch. The results also show that electricity use does not automatically lead to increased household income, but is much more complex process than discussed in existing research. The article further discusses the possible causes behind the phenomenon, proposes recommendations for better-informed energy policy, and provides important insights towards sustainable energy transition in Cambodia in the future. [ABSTRACT FROM AUTHOR]

Detailed analysis the disparity and reduction potential of clinker emission factors at the provincial level is important for regional reduction policies. Using the surveyed data from 185 new suspension and pre-heater (NSP) process lines and 69 shaft kiln lines, this study firstly analyzed the disparity in emission factors based on production process, production scale, and regional distribution in 2015. We found that the emission factor of the shaft kiln process (898.24 kg/t) is higher than that of the NSP process (858.59 kg/t), and that small-scale production lines have higher emission factors than large-scale lines both for the two process. China's clinker emission factors increase from the eastern to the western regions. Then, we estimated the reduction potential of structural adjustment, raw material substitution, and energy saving and fuel substitution in regional emission factors by 2030. The result shows that emission factors of the surveyed provinces will decrease by 101.41–174.60 kg/t compared to the values in 2015, which mainly contributes by energy saving and fuel substitution (65.98%), and raw material substitution (25.72%). And structural adjustment contributes only a small part reduction for most investigated provinces. The national average emission factor is estimated to be 715.33 kg/t in 2030, which indicates a reduction of 16.65%. These results can provide valuable feedback to government officials on the effectiveness of existing measures and also serve as a reference for future decisions on emission reduction polices. [ABSTRACT FROM AUTHOR]

Stabilizing climate change well below 2 °C and towards 1.5 °C requires comprehensive mitigation of all greenhouse gases (GHG), including both CO2 and non-CO2 GHG emissions. Here we incorporate the latest global non-CO2 emissions and mitigation data into a state-of-the-art integrated assessment model GCAM and examine 90 mitigation scenarios pairing different levels of CO2 and non-CO2 GHG abatement pathways. We estimate that when non-CO2 mitigation contributions are not fully implemented, the timing of net-zero CO2 must occur about two decades earlier. Conversely, comprehensive GHG abatement that fully integrates non-CO2 mitigation measures in addition to a net-zero CO2 commitment can help achieve 1.5 °C stabilization. While decarbonization-driven fuel switching mainly reduces non-CO2 emissions from fuel extraction and end use, targeted non-CO2 mitigation measures can significantly reduce fluorinated gas emissions from industrial processes and cooling sectors. Our integrated modeling provides direct insights in how system-wide all GHG mitigation can affect the timing of net-zero CO2 for 1.5 °C and 2 °C climate change scenarios. Stabilizing climate change requires simultaneous mitigation of all greenhouse gas emissions (GHGs). Here the authors examine 90 mitigation scenarios pairing different levels of CO2 and non-CO2 GHG abatement pathways to demonstrate the contributions of different GHGs towards 1.5 °C and 2 °C goals. [ABSTRACT FROM AUTHOR]

Industrial wastes can be used as alternative fuel sources for the substitution of fossil fuel if they contain good calorific values. Through waste-to-energy (WtE) pathway, energy can be harvested from industrial waste through combined heat and power (CHP; or commonly known as cogeneration) scheme. The latter is recognised as an efficient way to supply thermal and electrical energy simultaneously for process plant usage. In this work, cogeneration potential of an industrial waste of glycerine pitch is analysed. A mathematical technique based on process integration, known as automated targeting model (ATM) was extended to optimise the cogeneration and fuel inventory system simultaneously by considering single- and multi-period planning with varying fuel supply. A case study involving glycerine pitch from a palm refinery is demonstrated for the extended ATM. [ABSTRACT FROM AUTHOR]