Minimum Energy Requirements Research Articles

Розробка методики силового розрахунку вертикально орієнтованого захватного пристрою

Based on the main purpose of industrial robots, their gripping devices must provide reliable clamping of the parts they hold in different directions and modes of their movement and perform the necessary operations (installation, connection, pressing of parts, etc.). The process of transportation and positioning itself must be carried out in compliance with the following requirements: the maximum appropriate speed or acceleration; necessary accuracy; minimal force loads on the robot grip and structure; the necessary quality of the operation; minimum energy requirements; compliance with the necessary requirements for the safety of operations, etc. In addition, the gripping devices of robots should be versatile enough to be able to work with different parts in shape and size, as well as perform maintenance of different equipment, working with different devices, etc. Therefore, functional studies of gripping devices are quite important. One of the directions of such research is the creation of a methodology for force calculations taking into account the conditions discussed above, therefore the task is relevant today. During the period of existence and development of industrial robotics, the issue of force calculation of their gripping devices has always been relevant due to the fact that this is a working body that is constantly in contact with production objects of various shapes, materials and properties. In the process of manipulating production objects, they must not be damaged, while the robot's work cycle must also be precisely worked out in a certain period of time according to the production cycle. All these issues were considered most thoroughly in the studies of I.I. Pavlenka [1, 4], ShimonY. Nof, G.J. Monkman [3], Ya.I. Prots [2] and others. Particular attention was paid to the power of gripping devices in the works of I.I. Pavlenko. These studies are taken as the basis of the idea of substantiating the operating conditions of gripping devices and creating a methodology, different approaches to force calculation with its subsequent use in the design of these executive modules, as well as in the correcting programs of the industrial robot. Thus, the purpose of the scientific work is to study the power characteristics of the gripping device of an industrial robot under different conditions of its operation, to derive formulas for determining the minimum necessary clamping forces of the part, and to build the dependence of the calculated forces on the design characteristics of the gripper. It is worth noting that the relevance of this issue has increased many times today. This is due to the use of robotics not only in production, but also for military purposes. Industrial robots (manipulators) are used in the machine-building industry, which serve the main technological equipment, and in military affairs - mobile robots with built-in manipulators for taking dangerous objects. The method of force calculation proposed by us consists in determining the minimum necessary clamping forces.

Highly Efficient Year-Round Energy and Comfort Optimization of HVAC Systems in Electric City Buses

In this paper, we present a novel approach to perform highly efficient numerical simulations of the heating, ventilation, and air-conditioning (HVAC) system of an electric city bus. The models for this simulation are based on the assumption of a steady-state operation. We show two approaches to obtain the minimum energy requirement for a certain thermal comfort criterion under specific ambient conditions. Due to the computationally efficient approach developed, we can evaluate the model on a large dataset of 7500 scenarios in various ambient conditions to estimate the year-round performance of the system subject to different comfort requirements. Compared to a heating strategy based on positive temperature coefficient (PTC) elements, we can thus show that a heat pump (HP) can reduce the annual mean power consumption by up to 60%. Ceiling-mounted radiant heating elements complementing a PTC heating system can reduce the annual mean power consumption by up to 10%, while they cannot improve the energy efficiency when used in conjunction with a HP. Finally, a broad sensitivity study reveals the fact that improving the HP's heating-mode coefficient of performance (COP) manifests the largest leverage in terms of mean annual power consumption. Moreover, the annual energy expenditure for cooling are around eight times smaller than those for heating. The case study considered thus reveals that the advantages of improving the COP of the cooling mode are significantly lower.

ПРИМЕНЕНИЕ ГЕНЕТИЧЕСКОГО АЛГОРИТМА ДЛЯ ОПТИМИЗАЦИИ ДВУХИМПУЛЬСНОГО ПЕРЕЛЁТА В ЗАДАЧЕ О ВСТРЕЧЕ ДВУХ КОСМИЧЕСКИХ АППАРАТОВ НА ОРБИТЕ МАРСА

In this research, we delve into the application of genetic algorithms for optimizing the twoimpulse rendezvous maneuver of an active spacecraft with a passive spacecraft, situated at orbits with both higher and lower altitudes relative to the passive counterpart. Assumedly, the passive spacecraft resides in a circular Mars orbit at an altitude of 300 km, with defined orbital parameters. Through the employment of genetic algorithms, our primary objective is the optimization of rendezvous parameters, specifically focusing on the rendezvous duration and the initial velocity vector of the active spacecraft within the areocentric equatorial system, while simultaneously striving to minimize the requisite energy expenditure for the rendezvous. In both cases under consideration, we maintain an initial separation of 20 km between the spacecraft. In each case, we track the shift in the relative position vector of the active spacecraft with respect to the passive spacecraft. Our findings reveal that trajectories approximating 75 minutes in duration yield a global minimum energy requirement. Conversely, shorter trajectories necessitate a marginally larger energy expenditure, thereby embodying a trade-off between flight duration and energy expenditure. Interestingly, lengthening the duration of the rendezvous maneuver does not invariably result in a lower energy requirement. Moreover, a thorough numerical analysis uncovers a remarkable similarity in the optimization outcomes across both cases, with the rendezvous trajectory direction serving as the principal differential factor. This investigation furnishes crucial numerical insights into the optimization process of two-impulse rendezvous maneuvers, thereby substantiating the practical utility of genetic algorithms in this domain.

Energy-efficient virtual sensor-based deep reinforcement learning control of indoor CO2 in a kindergarten

High concentrations of indoor CO2 pose severe health risks to building occupants. Often, mechanical equipment is used to provide sufficient ventilation as a remedy to high indoor CO2 concentrations. However, such equipment consumes large amounts of energy, substantially increasing building energy consumption. In the end, the issue becomes an optimization problem that revolves around maintaining CO2 levels below a certain threshold while utilizing the minimum amount of energy possible. To that end, we propose an intelligent approach that consists of a supervised learning-based virtual sensor that interacts with a deep reinforcement learning (DRL)-based control to efficiently control indoor CO2 while utilizing the minimum amount of energy possible. The data used to train and test the DRL agent is based on a 3-month field experiment conducted at a kindergarten equipped with a heat recovery ventilator. The results show that, unlike the manual control initially employed at the kindergarten, the DRL agent could always maintain the CO2 concentrations below sufficient levels. Furthermore, a 58% reduction in the energy consumption of the ventilator under the DRL control compared to the manual control was estimated. The demonstrated approach illustrates the potential leveraging of Internet of Things and machine learning algorithms to create comfortable and healthy indoor environments with minimal energy requirements.

Study of Energy Integration in Chlorobenzene Production Process Using Pinch Technology

In this paper, the industrial application of detailed heat integration in the chlorobenzene production plant has been solved by using the Pinch design method. Designing a Heat Exchanger Network (HEN) through pinch analysis is an effective energy integration technology. In addition, minimizing unit and cost, operability and process control are essential parameters for selecting a suitable HEN design. In this research, the HEN of the existing process has been designed and analyzed using HINT software to minimize energy consumption and cost, thereby achieving maximum energy recovery. The analysis shows that the existing plant has been well integrated, and sound energy-saving effects and minimum energy requirements have been observed through the energy integration between processes. The total energy saving has been 91.80 %, while the energy recovery for heating and cooling have been 86.99 % and 96.23 %, respectively. Based on the economic analysis, the total annual cost of the proposed HEN design has been calculated to be 80912.5 $.

An investigation into the minimum energy requirements for transforming end-of-life cotton textiles into carbon fibre in an Australian context

The work presents on the relationship between temperature, time and carbon content in the preparation of a carbon fibre cloth from end-of-life cotton textiles. The aim of this investigation was to identify the minimum energy requirements for this textile recycling opportunity. The composition of the carbon fibre was studied using elemental combustion instruments and X-ray fluorescence. The structure of the carbon fibres was studied through scanning electron microscopy and X-ray diffraction. Through this process it was determined that the optimum temperature and time requirements were 1150 °C and 30 min to prepare a carbon fibre under the conventional definition, which requires carbon content to be in excess of 90%. The minimum temperature and time requirements for a lower grade carbon fibre of 80% carbon content are 650 °C and 30 min. This research can support efforts to improve circularity of cotton textiles for high value applications in environmental management or electronic markets. This in turn could support these industries to reduce their carbon footprint and meet their sustainable procurement targets for greater uptake of recycled content materials.

Novel circularity and sustainability assessment of symbiosis networks through the Energy Quality Pinch concept

Circular Economy is a well-known concept to mitigate global resource depletion issues. The sustainability of a system is closely related to its environmental performance, which is directly linked to energy consumption. This work provides a circularity assessment tool by determining the minimum system energy requirements, according to the Energy Quality Factor, as it indicates the useful energy that can be extracted from material and energy flows. The proposed tool is Energy Quality Pinch Analysis which identifies the minimum energy requirements for a circular system and shows the system's sustainability. The analysis considers cascades of the energy used and released by recycling and symbiosis processes, evaluating the minimal external energy flows: high-quality energy input and waste energy output. The method is applied to case studies, including Total Site Heat and Power Integration, chemical energy reuse in wastewater systems, and Municipal Solid Waste management. Practical energy conversion technologies in each study are proposed as well. The results of the case studies indicate that the degree of energy recovery rate can be as high as 60% for the case of the utility system and higher for the cases of wastewater and municipal waste treatment, providing potentially valuable guidance to system designers.

Dietary Intake of Women from Two Australian Cities Living in Poverty

ABSTRACT This study assessed the quantity and quality of food consumed by Australian Capital Territory and Perth women living in poverty from July to October 2017. Sixty-six women, recruited through charitable food organizations, participated in one-on-one interviews and 24-hr dietary recall. Overall, diet quality was poor. Daily energy intakes ranged between 96 kJ-11450 kJ. 75% of women consumed below the minimum energy requirement for their age. Daily serve recommendations and Estimated Average Requirements for calcium, iron and potassium were not met. Urgent action is needed from government, health, food, and community sectors to address the ongoing challenges faced by women experiencing food insecurity.

Multipath Routing in Wireless Body Area Sensor Network for Healthcare Monitoring.

Mobility and low energy consumption are considered the main requirements for wireless body area sensor networks (WBASN) used in healthcare monitoring systems (HMS). In HMS, battery-powered sensor nodes with limited energy are used to obtain vital statistics about the body. Hence, energy-efficient schemes are desired to maintain long-term and steady connectivity of the sensor nodes. A sheer amount of energy is consumed in activities such as idle listening, excessive transmission and reception of control messages, packet collisions and retransmission of packets, and poor path selection, that may lead to more energy consumption. A combination of adaptive scheduling with an energy-efficient protocol can help select an appropriate path at a suitable time to minimize the control overhead, energy consumption, packet collision, and excessive idle listening. This paper proposes a region-based energy-efficient multipath routing (REMR) approach that divides the entire sensor network into clusters with preferably multiple candidates to represent each cluster. The cluster representatives (CRs) route packets through various clusters. For routing, the energy requirement of each route is considered, and the path with minimum energy requirements is selected. Similarly, end-to-end delay, higher throughput, and packet-delivery ratio are considered for packet routing.

Optimization of bioactives extraction from grape marc via a medium scale ambient temperature system and stability study.

A scalable procedure with minimum energy requirements, MSAT (Medium Scale Ambient Temperature), in combination with solvents generally recognized as safe (GRAS), has been optimized to obtain polyphenolic extracts from white grape (Vitis vinifera) marc. The solvents considered were propylene glycol (Pg), ethanol (Et), and ethyl lactate (Lc), as well as their respective hydro-organic mixtures. In a first approach, the operating parameters were optimized through a response surface matrix: extraction solvent volume (range 10-150 mL), marc mass (range 20-200 g) and marc/dispersant mass ratio (range 0.5-2 g⋅g-1), using the total polyphenol content (TPC) and the antioxidant activity (AA) of the extracts as response parameters. The highest TPC (5,918 mgGAE⋅L-1) and AA (44 mmolTE⋅L-1) values were obtained using 200 g marc and 100 mL solvent. Regarding the type of solvent, a better response was reached with Lc > Et > Pg > H2O obtaining a polyphenol concentration of 252 mg⋅L-1 for the hydro-organic isovolumetric ratio of ethyl lactate. In addition, the stability of the extracts was studied for 62 days. The effect of factors such as temperature, light exposure, and oxidative reactivity was evaluated. The bioactivity indices showed no changes with the storage conditions of the extracts in the first month of analysis, after which 75% of the antioxidant activity as the concentration of the polyphenolic profile (204 mg⋅L-1) remains. The absence of reactive oxygen and the cooling of the extract (4°C) were the most determining factors (p < 0.05) in modulating the stability of the total polyphenolic profile.

Economic analysis of threshing and shelling machine service provision to reduce post-harvest loss in Ethiopia

The Sasakawa Africa Association (SAA) has been addressing the neglected post-harvest sector in Ethiopia through promoting improved storage facilities and introducing handheld and motorized crop shelling and threshing machines. However, post-harvest technologies are poorly adopted by the farmers although the traditional threshing methods often result in high grain losses and low-quality produces due to low awareness of the farmers and service providers on the benefits of the technologies. This study, therefore, was conducted in May 2020 to determine the socio-economic benefits of the threshing/shelling machine so as to inform the service providers on how to improve the adoption of the machine. A total of eight youth group service providers in four woredas of Oromia and Amhara regions in Ethiopia were selected for the study. In a unimodal rainfall production region, the Bako model maize sheller and the dehusker machines were assessed, whereas in a bimodal production region the multi-crop thresher was evaluated. Primary data were sourced through Focus Group Discussions (FGD) and Key Informant Interviews (KII) and secondary data were extracted through document review. Discounted economic parameters such as Net Present Value (NPV), Internal Rate of Return (IRR) and Benefit Cost Ratio (BCR) were used for determining the profitability of the businesses. The result of the actual cashflow analysis in the unimodal area showed that the multi-crop thresher generated a negative NPV (USD -970) with IRR value of -6% and a BCR value of 0.87. On the contrary, in the bimodal area, the NPV was found to be positive (USD 1917.3) with a BCR of 1.21 and IRR value 36%. Congruently, the Bako model maize sheller machine resulted in NPV of USD 8227.5, BCR value of 3.51 with IRR value of 133%. On the other hand, the dehusker machine generated NPV of USD 2247.5 with a BCR of 1.45, and IRR of 24%. The partial budget analysis of the farmers revealed that the threshing machine reduced the threshing costs by USD158.2 (51.9%) per hectare of land compared to the traditional threshing method. On the basis of the minimum food energy requirement, in the two districts alone, the maize grain that was lost through traditional shelling would have fed 3,939 individuals or 788 households, whereas for teff crop, the loss would have fed 6,163 adults or 1233 households throughout the year. Based on the findings, the authors recommend to scale-up the introduction of the machines in the bimodal production areas where two harvesting seasons exist and increase the service charge and working hours- in the unimodal area to improve entrepreneurs’ profit and adoption of the machines. Key words: post-harvest loss, shelling, threshing, dehusking, economic analysis, food security

Benthic studies adjacent to Sakhalin Island, Russia 2015 III: benthic energy density spatial models in the nearshore gray whale feeding area

Energy densities of six dominant benthic groups (Actinopterygii, Amphipoda, Bivalvia, Cumacea, Isopoda, and Polychaeta) and total prey energy were modeled for the nearshore western gray whale feeding area, Sakhalin Island, Russia, as part of a multi-disciplinary research program in the summer of 2015. Energy was modeled using generalized additive mixed models (GAMM) with accommodations for zero-inflation (logistic regression and hurdle models) and regression predictions combined with kriging to interpolate energy densities across the nearshore feeding area. Amphipoda energy density was the highest nearshore and in the south whereas Bivalvia energy density was the highest offshore and in the northern portion of the study area. Total energy was the highest in mid-range distances from shore and in the north. Amphipoda energy density was higher than minimum energy estimates defining gray whale feeding habitats (312–442 kJ/m2) in 13% of the nearshore feeding area whereas total prey energy density was higher than the minimum energy requirement in 49% of the habitat. Inverse distance-weighted interpolations of Amphipoda energy provided a broader scale representation of the data whereas kriging estimates were spatially limited but more representative of higher density in the southern portion of the study area. Both methods represented the general trend of higher Amphipoda energy density nearshore but with significant differences that highlight the value of using multiple methods to model patterns in highly complex environments.

Future without Nuclear Energy; is it Feasible, is it Sensible?

Considering the necessity and future role of nuclear energy as relevant to the climate problem, we have focused on the period to the year 2065. For quantification of the required emission reduction we have used IEA WEO 2009 and WEO 2011 data as presented in their Reference strategies predicting emissions with business as usual practices, and WEO 450 Energy strategies which show the time development of allowed emissions consistent with a limit on the global temperature increase of 2 ºC and the peak CO2 concentration of 450 ppm. By extrapolating these data to the year 2065 we obtain 77.4 GtCO2-eq for Reference emission and 10 GtCO2-eq for WEO 450 strategy allowing emission, resulting in 67.4 GtCO2-eq reduction required to come down to sustainable WEO 450 trajectory. The large contributions to emission reduction from fusion energy and fossil fuel with carbon separation and storage are not likely. Main carbon non-emitting sources assumed in the years up to 2065 are proven technology nuclear fission and renewable sources. In our specified strategy aimed to achieve WEO 450 target we assumed an energy mix including nuclear power build-up in the period 2025-2065 to the level of 3300 GW in 2065. With the resulting nuclear contribution of 25.2 GtCO2 to the total required emission reduction of 67.4 GtCO2, what remains for renewable sources, energy saving and increased efficiency of energy use to contribute are prodigious 42.2 GtCO2-eq. Assuming that energy saving and more efficient energy use will by 2065 effect an annual reduction between 10 to 16 GtCO2-eq, remaining 26.2 to 32.2 GtCO2, respectively 27290 and 33540 TWh would be the task for renewable energy sources. Our estimates about contribution of renewable sources going as far as 2065 are based on EREC prediction for EU and on our extension to world total with EREC and GWEC prediction as a guide. Our high, but still credible estimates of predicted world renewable energy contribution by 2065 come to the similar figures between 29260 and 36180 TWh. However, without nuclear contribution in 2065, renewable energy contribution would have to be doubled, practically impossible task in the time period in consideration. Resulting contributions by renewable sources, probably their upper limits, allow some conclusions about the role of nuclear energy in future decades. By combining highest contributions from energy saving, efficiency increase and other measures to reduce emission, apart from energy production, with highest prediction for renewable sources contribution, we obtain the minimum nuclear energy requirement of about 2190 GW in 2065. This minimum nuclear strategy should be planned and prepared for, unless there is strong evidence that other carbon free energy sources (CCS or fusion) could be developed in time. Expansion of nuclear power by about 1800 GW by 2065 would come from different and already developed industrial sector, which can give its contribution to the energy mix, without obstructing the build-up of renewable sources. It would not be wise to forfeit nuclear contribution at least in the period to 2065, critical for the control of climate change.

Metals extraction on Mars through carbothermic reduction

In situ resource utilization (ISRU), and specifically the extraction and production of structural metals from Martian soil, is important for supporting further exploration, habitat and industrial developments on Mars. Considering Mars's atmospheric conditions and soil compositions, systematic analyses (supported by thermodynamic calculations) on possible metal extraction processes have been carried out. The analyses suggest that carbothermic reduction of Martian regolith would be the preferable starting point considering the abundance of carbon in the form of CO2 in the Martian atmosphere. It was proposed that carbon would be sourced from the cooling of carbon monoxide produced from CO2 electrolysis (MOXIE) from the Martian atmosphere. An Ellingham diagram showing the relative stability of oxides at Mars's atmospheric pressure of 7 mbar has been constructed; detailed equilibrium calculations to evaluate the carbothermic reduction of Martian regolith have also been carried out. The thermodynamic calculations predicted the formation of liquid Fe alloy with 99.9% conversion when the regolith was reacted with carbon (at approximately 10 wt% addition) at 1120 °C and 7 mbar. The impurities in the liquid Fe alloy were predicted to be mainly Si, C, Cr, and P. The hot gas produced from the process was predicted to be rich in CO (91%) and could be used for the preheating of the regolith. The CO could also be recycled and condensed to produce C (that could be re-used for the carbothermic reduction). The minimum energy requirement for the carbothermic reactor was calculated to be 3.37 MWh/tonne of liquid iron alloy (while the total energy requirement including MOXIE and agglomeration was calculated to be 15.51 MWh/tonne of liquid iron alloy). A generic process flowsheet has been developed considering these results.

Farming Systems, Food Security and Farmers' Awareness of Ecosystem Services in Inland Valleys: A Study From Côte d'Ivoire and Ghana

Inland valleys (IVs) in West African countries have increasingly been used for crop production, including rice cultivation. Though it is widely assumed that IVs have a high potential to contribute to food security of West African countries, a comprehensive assessment of farming systems addressing agricultural, institutional, food security, poverty, and ecosystem indicators is still lacking. This study characterizes IVs' smallholder farm households at the regional and farm type level using Rural Household Multiple Indicator Survey (RHoMIS) data collected from 733 randomly selected farm households in four agro-ecological regions, i.e., Bouaké and Gagnoa in Cote d'Ivoire, and Ahafo Ano North and Ahafo Ano South in Ghana. A farm typology is developed, and farm households are characterized with regard to demographic, agricultural, economic, and institutional indicators. Furthermore, farm households' food security and poverty status, and the importance of rice in the portfolio of crops, is assessed. Finally, farmers' awareness of different ecosystem services (ES) for their food security is examined. Four farm types are identified, i.e., farmers who rent all the land cultivated, farmers who own some land and rent extra land, farmers who own and cultivate all their land, and farmers cultivating only a part of the land they own. We find that the variation in farm households' demographic, economic, and institutional characteristics is greater between regions than within regions. Crop production, either for direct consumption or marketing, especially rice production, is the main contributor to daily energy intake, followed by wild food consumed. Still, a substantial percentage of the farm households (16–38%) in all regions cannot meet minimum daily energy requirements. Farmers of all farm types, and in all regions, attach high relevance to IVs' provisioning ES, particularly the ability to provide food. A majority of farmers in all regions highlighted the relevance of regulating ES, including climate regulation, water storage, and groundwater values for their wellbeing. In contrast, farmers attached relatively lower relevance to cultural ES. Interventions to improve national rice production need to acknowledge and preserve the diversity ES that IVs provide to smallholder farm households.

Boron based intramolecular heterocyclic frustrated Lewis pairs as organocatalysts for CO2 adsorption and activation.

The massive increase in the amount of carbon dioxide (CO2 ) in the atmosphere has led to serious environmental problems. One of the best ways to tackle this problem is the CO2 capture and its utilization as a C1 carbon source for the production of industrially valuable chemicals. But the thermodynamic stability of the CO2 molecule poses a great challenge in its transformation. Since the last two decades, various metal-based and organic catalysts have been developed for the adsorption and activation of CO2 . Among all the catalysts the Frustrated Lewis pairs (FLPs) have been shown great potential in CO2 capture and conversion. Thus, in the present work, Intramolecular Frustrated Lewis pairs (IFLP) based on N-Heterocycles with boron group functionalization at the α-position to N has been theoretically investigated for CO2 activation. Thorough orbital analysis has been carried out to investigate the reactivity of the proposed catalytic systems. The result shows that the considered IFLPs are capable of activating CO2 with minimum energy requirements. The CO2 activation energy range between 8 and 14 kcal/mol. The non-polar solvent was found to be the suitable medium for the reaction. Also, the reversibility of the adducts formed with the IFLPs can be controlled by appropriate substitution at B atom in the IFLPs.

Technological Options for Direct Air Capture: A Comparative Process Engineering Review.

The direct capture of CO2 from ambient air presents a means of decelerating the growth of global atmospheric CO2 concentrations. Considerations relating to process engineering are the focus of this review and have received significantly less attention than those relating to the design of materials for direct air capture (DAC). We summarize minimum thermodynamic energy requirements, second law efficiencies, major unit operations and associated energy requirements, capital and operating expenses, and potential alternative process designs. We also highlight process designs applied toward more concentrated sources of CO2 that, if extended to lower concentrations, could help move DAC units closer to more economical continuous operation. Addressing shortcomings highlighted here could aid in the design of improved DAC processes that overcome trade-offs between capture performance and DAC cost.

Electrochemical Advanced Oxidation of Carbamazepine: Mechanism and optimal operating conditions

Effective electrochemical degradation of carbamazepine (CBZ) in water was accomplished with minimal energy and chemical requirements, showing that electrochemical Advanced Oxidation Processes (eAOPs) with a Boron-Doped Diamond (BDD) anode are a promising method for the in situ degradation of contaminants of emerging concern (CECs). The influence of several operating parameters (i.e., pH, temperature and initial anolyte and pollutant concentrations) was determined through the Taguchi optimization method. Optimal conditions corresponded to 1 μM CBZ, pH 2, 30 °C, 10 mM Na2SO4 and 50 A m−2, resulting in complete CBZ removal in less than 5 min. Complementary scenarios with different ion species, energy sources and current densities further corroborated the suitability of the optimum. Moreover, they revealed that the optimal conditions were driven by the presence of both SO42− and NO3− ions in solution. Hence, the optimal degradation results were also attained when replacing HNO3 by NaNO3, which allowed to operate without prior pH adjustments. The contribution of •OH and SO4•− radicals was studied through scavenging tests and it was for the first time tentatively ascribed to the Oxygen Evolution Reaction (OER), since the selection of the operating potential influences the type of oxidative species present. Finally, the primary transformation products formed during CBZ degradation under optimal conditions were investigated.

Which thermochemical water-splitting cycle is more suitable for high-temperature concentrated solar energy?

The manuscript reviews the thermochemical water-splitting cycles not in general (many other works have covered this topic) but specifically for producing hydrogen coupled with high temperature concentrated solar energy which is available at temperatures of 1000 to 1100 °C. This is important to benefit from synergies with near future dispatchable concentrated solar power, simply replacing the power cycle with the thermochemical hydrogen production plant. The review shows as three-step cycles are those benefiting the most from the synergy with higher solar flux dispatchable concentrated solar power with thermal energy storage, also profiting in terms of technology readiness level from past experiences in thermochemical water-splitting cycles for nuclear power plants, and the affordable complexity of the cycle. From preliminary evaluations, three-step cycles may permit CO2-free hydrogen production within a decade at a competitive cost with green hydrogen as well as the current prevailing production of hydrogen from hydrocarbons at less than $1 per 1 kg. The thermochemical pathway has the same minimum energy requirement as electrolysis, despite the conversion efficiencies achieved so far have been much less because of the reduced development. Since the collection of solar thermal energy is much easier and more efficient than solar photovoltaic conversion, the thermochemical pathway has the potential to deliver a cost of hydrogen smaller than green hydrogen from solar photovoltaic electricity and electrolyzers.

Nanosponges for Water Treatment: Progress and Challenges

Nanosponges have shown promising capabilities for efficient removal of organic/inorganic pollutants from water based on absorption/adsorption and disinfection processes. The application of nanosponges (especially cyclodextrin-based nanosponges) can be considered a cost-effective strategy with minimal energy and time requirements in comparison to other routinely deployed water treatment modalities. These polymers with unique physicochemical properties, architectures, and highly cross-linked three-dimensional networks need to be further explored for removing pollutants with simultaneous eliminations of microbial contaminants from wastewater. Additionally, the surface functionalization of these nanosponges utilizing magnetic, titanium dioxide, and silver nanomaterials can significantly improve their properties for water remediation purposes, although nanosponges altered with carbon nanotubes and metallic nanomaterials/nanocatalysts for water treatment appliances are barely explored. Notably, crucial factors such as adsorbent type/dosage, contact time, competing ions, adsorption isotherm models, kinetics, thermodynamics, and reaction/experimental conditions (e.g., molar ratios, temperature, and pH) are important aspects affecting the adsorption and removal of pollutants using nanosponges. Furthermore, the nanotoxicity and biosafety of these nanosponge-based systems utilized for water treatment should be comprehensively evaluated. Herein, recent advancements in the design and deployment of nanosponge-based systems for removing organic/inorganic pollutants from water and wastewater are deliberated with an emphasis on challenges and perspectives.