Energetic Comparison Research Articles

Energetic comparison between different configurations of a concentric magnetic gearbox for industrial applications

Abstract Mechanical gearboxes can achieve high torque densities. They often require recurring lubrication, cooling and maintenance, and reliability can be a significant issue, particularly for remote systems such as wind turbines, or during the operation of a ship under special conditions or circumstances that require an immediate response. For these reasons, a new type of gearbox is increasingly gaining ground, namely magnetic gearboxes (MG). It operates without contact between the moving parts and consists mainly of three concentric ‘rings’ with a number of permanent magnets and iron poles to achieve a specific gear ratio. This article presents an energy comparison in terms of induced torque between different configurations of a concentric magnetic gearbox in terms of material construction for the cores, magnets position and number of pole pairs. The data were realised using the two-dimensional Finite Element Method (FEM). The results show that although the polymer-based configuration shows some potential, the ferrous core with external magnets significantly outperforms it in terms of torque and efficiency.

Energetic Comparison between Pneumatic and Traditional Disintegration in the Vinification of Negroamaro Grapes

Energetic Comparison between Pneumatic and Traditional Disintegration in the Vinification of Negroamaro Grapes

Energy loss comparison between kinematically equivalent mechanisms: Slider-crank and eccentric cam

The reduction of energy consumption in industrial processes is a challenge to be confronted within the framework of the United Nations’ Sustainable Development Goals. The present study compares the energy loss per cycle of two kinematically equivalent mechanisms: a slider-crank and an eccentric cam with a translational roller follower. We use the work-energy theorem to evaluate energy losses by using a viscous friction model in a stationary regime. The innovation of this study lies in the energetic comparison to identify the best and worst alternatives by analyzing the contribution of their main geometrical parameters, such as crank length, rod-crank length ratio, roller radius and follower offset. The aim is to provide guidelines to help machinery designers to take relevant preliminary decisions that affect energy efficiency. Herein, we include analytical models, numerical simulations and experimental results using a test stand that can be adapted to other planar one degree-of-freedom mechanisms. In this context, we conclude that an eccentric cam mechanism with a big roller radius and no offset provides the best energetic efficiency among the aforementioned mechanisms.

Energetic comparison of exciton gas versus electron-hole plasma in a bilayer two-dimensional electron-hole system

Energetic comparison of exciton gas versus electron-hole plasma in a bilayer two-dimensional electron-hole system

Energetic Comparison of Flow-Electrode Capacitive Deionization and Membrane Technology: Assessment on Applicability in Desalination Fields.

Flow-electrode capacitive deionization (FCDI) is a promising technology for sustainable water treatment. However, studies on the process have thus far been limited to lab-scale conditions and select fields of application. Such limitation is induced by several shortcomings, one of which is the absence of a comprehensive process model that accurately predicts the operational performance and the energy consumption of FCDI. In this study, a simulation model is newly proposed with initial validation based on experimental data and is then utilized to elucidate the performance and the specific energy consumption (SEC) of FCDI under multiple source water conditions ranging from near-groundwater to high salinity brine. Further, simulated pilot-scale FCDI system was compared with actual brackish water reverse osmosis (BWRO) and seawater reverse osmosis (SWRO) plant data with regard to SEC to determine the feasibility of FCDI as an alternative to the conventional membrane processes. Analysis showed that FCDI is competent for operation against brackish water solutions under all possible operational conditions with respect to the BWRO. Moreover, its distinction can be extended to the SWRO for seawater conditions through optimization of its total effective membrane area via scale-up. Accordingly, future directions for the advancement of FCDI was suggested to ultimately prompt the commercialization of the FCDI process.

Structural basis for inhibition of a GH116 β-glucosidase and its missense mutants by GBA2 inhibitors: Crystallographic and quantum chemical study

The crystal structure of the Thermoanaerobacterium xylanolyticum in glycoside hydrolase family 116 (TxGH116) β-glucosidase provides a structural model for human GBA2 glucosylceramidase, an enzyme defective in hereditary spastic paraplegia and a potential therapeutic target for treating Gaucher disease. To assess the therapeutic potential of known inhibitors, the X-ray structure of TxGH116 in complex with isofagomine (IFG) was determined at 2.0 Å resolution and showed the IFG bound in a relaxed chair conformation. The binding of IFG and 7 other iminosugar inhibitors to wild-type and mutant enzymes (Asp508His and Arg786His) mimicking GBA2 pathogenic variants was then evaluated computationally by two-layered ONIOM calculations (at the B3LYP:PM7 level). Calculations showed that six charged residues, Glu441, Asp452, His507, Asp593, Glu777, and Arg786 influence inhibitor binding most. His507, Glu777 and Arg786, form strong hydrogen bonds with the inhibitors (∼1.4-1.6 Å). Thus, the missense mutation of one of these residues in Arg786His has a greater effect on the interaction energies for all inhibitors compared to Asp508His. In line with the experimental data for the inhibitors that have been tested, the favorable interaction energy between the inhibitors and the TxGH116 protein followed the trend: isofagomine > 1-deoxynojirimycin > glucoimidazole > N-butyl-deoxynojirimycin ≈ N-nonyl-deoxynojirimycin > conduritol B epoxide ≈ azepane 1 > azepane 2. The obtained structural and energetic properties and comparison to the GBA2 model can lead to understanding of structural requirement for inhibitor binding in GH116 to aid the design of high potency GBA2 inhibitors.

Synthesis and Characterization of Na4Si2Se6-tP24 andNa4Si2Se6-oP48,Two Polymorphs with Different Anionic Structures.

Two different polymorphs of the new selenosilicate Na4Si2Se6 were synthesized by solid-state reactions. The high-temperature polymorph Na4Si2Se6-tP24 crystallizes in the tetragonal space group P42/mcm (No. 132) with lattice parameters a = 7.2793(2) Å, c = 12.4960(4) Å, and V = 662.14(3) Å3. The main structural motifs are isolated Si2Se6 units of two edge-sharing SiSe4 tetrahedra. The high-pressure/low-temperature polymorph Na4Si2Se6-oP48 crystallizes in the orthorhombic space group Pbca (No. 61) with lattice parameters a = 12.9276(1) Å, b = 15.9324(1) Å, c = 6.0349(1) Å, and V = 1243.00(2) Å3 showing zweier single chains ∞1[Si2Se6]4-. The lattice parameters of Na4Si2Se6-tP24 were determined by single-crystal X-ray diffraction, whereas those of Na4Si2Se6-oP48 were investigated by powder X-ray diffraction. Both modifications crystallize in new structure types. An energetic comparison of the two polymorphs and further hypothetical structure types was carried out by density functional theory modeling. Calculations reveal that the polymorphs are very close in energy (ΔE = 3.4 kJ mol-1). Impedance spectroscopic measurements show ionic conductivity (σspec = 1.4 × 10-8 S cm-1 at 50 °C and 6.8 × 10-6 S cm-1 at 200 °C) with an activation energy of EA = 0.54(2) eV for Na4Si2Se6-oP48.

Performance Analysis of WHR Systems for Marine Applications Based on sCO2 Gas Turbine and ORC

Waste heat recovery (WHR) can represent a solution to improve the efficiency of ships’ propulsion, helping to exceed stringent greenhouse gas emission limits. This is particularly suitable in the case of propulsion based on gas turbines due to their medium-high temperature level of the exhaust gases. This study analyzes the performance of a hybrid energy grid, in which the heat is recovered by the exhaust gases of an aeroderivative gas turbine, a GE LM2500+, when the bottoming system is a supercritical CO2 gas turbine. Given the issues and peculiarities related to the onboard installation, where size and weight are fundamental concerns, six WHR schemes have been analyzed. They span from the simple cycle to partial preheated and regenerative, to a cascade layout in which an ORC system receives thermal power by the sCO2 GT. The influence of the seawater temperature on the performance of the hybrid energy system has been also considered. The energetic and exergetic performance comparison of the different schemes has been carried out by using the commercial software Thermoflex. The results showed that an increase in overall performance by up to 29% can be obtained and that the increase in seawater temperature can lead to a decrease in the overall performance.

Renewable Electricity for Decarbonisation of Road Transport: Batteries or E-Fuels?

Road transport is one of the most energy-consuming and greenhouse gas (GHG) emitting sectors. Progressive decarbonisation of electricity generation could support the ambitious target of road vehicle climate neutrality in two different ways: direct electrification with onboard electrochemical storage or a change of energy vector with e-fuels. The most promising, state-of-the-art electrochemical storages for road transport have been analysed considering current and future technologies (the most promising ones) whose use is assumed to occur within the next 10–15 years. Different e-fuels (e-hydrogen, e-methanol, e-diesel, e-ammonia, E-DME, and e-methane) and their production pathways have been reviewed and compared in terms of energy density, synthesis efficiency, and technology readiness level. A final energetic comparison between electrochemical storages and e-fuels has been carried out considering different powertrain architectures, highlighting the huge difference in efficiency for these competing solutions. E-fuels require 3–5 times more input energy and cause 3–5 times higher equivalent vehicle CO2 emissions if the electricity is not entirely decarbonised.

Economic and Energetic Assessment and Comparison of Solar Heating and Cooling Systems

Solar heating and cooling (SHC) systems are currently attracting attention, especially in times of increasing energy prices and supply crises. In times of lower energy prices, absorption SHC systems were not competitive to compression cooling supported by photovoltaic (PV) modules due to the high investment costs and total energy efficiency. This paper aims to discuss the current changes in energy supply and energy prices in terms of the feasibility of the application of a small absorption SHC system in a mild Mediterranean climate. The existing hospital complex restaurant SHC system with evacuated tube solar collectors and a small single-stage absorption chiller was used as a reference system for extended analysis. Dynamic simulation models based on solar thermal collectors, PV modules, absorption chillers and air-to-water heat pumps were developed for reliable research and system comparison. The results showed that primary energy consumption in SHC systems designed to cover base energy load strongly depends on the additional energy source, e.g., boiler or heat pump. Absorption SHC systems can be price competitive to air-to-water heat pump (AWHP) systems with PV collectors only in the case of reduced investment costs and increased electricity price. To reach acceptable economic viability of the absorption SHC system, investment price should be at least equal to or lower than a comparable AWHP system.

The Stacking Faulted Nature of the Narrow Gap Semiconductor Sc2Si2Te6

AbstractCrystals of Sc2Si2Te6 have been grown and its crystal, micro‐ and electronic structures were investigated. The layered character of the title compound exhibits stacking faults that impede a full structural characterization by single crystal X‐ray diffraction due to diffuse scattering. Based on high resolution transmission electron micrographs and diffraction patterns, the stacking faulted nature of the real structure of Sc2Si2Te6 has been revealed. Different stacking models were derived from the idealized, faultless structure and the stacking disorder was quantitatively analyzed by Rietveld refinement of powder X‐ray diffraction patterns. An energetic comparison of the stacking models by density functional theory is in line with the experimental observations. Further, the bonding situation was investigated by electronic structure calculations. Sc2Si2Te6 is a narrow gap semiconductor with an indirect band gap of 0.65 eV.

Energetic Comparison of Vertical Bifacial to Tilted Monofacial Solar

In this article, a vertical bifacial + reflector configuration is presented as a candidate for solar canals and other applications that allow dual use of the land. Modeling with weather data from Merced, CA shows output to be competitive with fixed 20° tilt systems, with south-facing vertical orientation showing 117% and 87% of annual output of south-facing 20° systems with and without a reflector, respectively. Repetition with weather data from Houston, Denver, and Miami produces similar results, with values ranging from 112%–121% and 82%–94%, which serve as conservative estimates due to lack of modeled soiling on tilted systems in the latter comparison. South-facing vertical orientations have better performance in nonsummer months relative to other systems, resulting in a flatter seasonal curve, with useful implications for load balancing and energy storage. East- and west-facing vertical orientations outperform their fixed tilt defaults, even without a reflector, and tolerate higher dc/ac inverter ratios than similar south-facing vertical orientations before appreciable clipping effects are seen.

Energetic and exergetic efficiency comparison of recuperative transcritical organic Rankine cycles under different pure and mixture fluids

AbstractA thermodynamic model of basic and recuperative transcritical organic Rankine cycles (TRCs) associated with using five pure and six mixed fluids as working fluids has been developed. This model can be employed to investigate the effects of recuperators at inlet expander temperatures (Texp,in) of 150–200°C and inlet expander pressures (Pexp,in) of 3.7–6.9 MPa. The ratio of change (ROC) of the first‐ and second‐law efficiencies (ηI and ηII) was positively correlated with the heat transfer rate of the recuperator and exhibited an opposite trend for a specific volume ratio. ROC was substantially affected by operating parameters and working fluid. However, the recuperator heat transfer rate was negligibly affected by the mixture temperature glide (Tglide). A universal empirical equation of ηI,II was proposed for both TRC configurations. The equation, a function of the specific volume ratio, can predict the system efficiencies for pure and mixed fluids, even if a mixture has an arbitrary mole fraction. As Tglide of R600a‐base mixture and R245fa/R134a was lower than 16 K, they had low error rates and low standard deviations. Finally, the equation was highly accurate in ηII prediction, particularly at a Texp,in of 160°C and 170°C and a Pexp,in of 4.9–5.8 MPa.

Exploration of Somatostatin Binding Mechanism to Somatostatin Receptor Subtype 4.

Somatostatin (also named as growth hormone-inhibiting hormone or somatotropin release-inhibiting factor) is a regulatory peptide important for the proper functioning of the endocrine system, local inflammatory reactions, mood and motor coordination, and behavioral responses to stress. Somatostatin exerts its effects via binding to G-protein-coupled somatostatin receptors of which the fourth subtype (SSTR4) is a particularly important receptor mediating analgesic, anti-inflammatory, and anti-depressant effects without endocrine actions. Thus, SSTR4 agonists are promising drug candidates. Although the knowledge of the atomic resolution-binding modes of SST would be essential for drug development, experimental elucidation of the structures of SSTR4 and its complexes is still awaiting. In the present study, structures of the somatostatin–SSTR4 complex were produced using an unbiased, blind docking approach. Beyond the static structures, the binding mechanism of SST was also elucidated in the explicit water molecular dynamics (MD) calculations, and key binding modes (external, intermediate, and internal) were distinguished. The most important residues on both receptor and SST sides were identified. An energetic comparison of SST binding to SSTR4 and 2 offered a residue-level explanation of receptor subtype selectivity. The calculated structures show good agreement with available experimental results and indicate that somatostatin binding is realized via prerequisite binding modes and an induced fit mechanism. The identified binding modes and the corresponding key residues provide useful information for future drug design targeting SSTR4.

Assembling high nitrogen isomeric energetic molecules via a lithium-mediated concerted [2 + 3] reaction of two diazo compounds

The search for high nitrogen isomeric energetic molecules and comparison of their structure–property relationship are always attractive in the field of energetic materials. In this paper, a novel lithium-mediated concerted [2 + 3] reaction with two diazo compounds has been accomplished which leads to the simultaneous formation of two isomeric cyanotetrazoles (2a and 2b). The cyano group in cyanotetrazoles was further converted to tetrazole or tetrazole N-oxide to form tricyclic heterocyclic products (3a, 3b, 7a, and 7b). The energetic properties of the compounds were studied. A representative compound 3a (Td = 220 °C, D = 9052 m s−1, IS = 13 J, FS = 200 N) has better detonation performances, higher thermal stability and lower mechanical sensitivities than RDX, which is expected to serve as a potential energetic material.

EXPERIMENTAL ASSESSMENT OF THE AGRICULTURAL WASTES ENERGY POTENTIAL FROM SINALOA, MEXICO

ABSTRACT: In Sinaloa, agricultural and livestock practices are extensive but proportionally generate organic wastes that subsequently produce greenhouse gases and negatively impact water bodies. In this research, a laboratory-scale up-flow anaerobic reactor was configured and evaluated to treat combined agricultural and livestock wastes. Subsequently, the quality and yield of the biogas were used to make an energetic and economic comparison with Liquefied Petroleum Gas (LPG). The results were also projected for the energy needs of the pilot community from which the waste was obtained. The reactor used was a 2.4 L reactor operated continuously at 45±2 °C and HRT of 7.2 d, with an organic load of 15000 mg/L. Carbon/nitrogen ratios of 25:1 and 32:1 were evaluated. With the 25:1 ratio, 1650 mL/d of biogas were obtained. With this ratio, greater stability was observed, and a higher proportion of methane. On average, 70% was methane (once stabilization was reached), converting it into biofuel. The projection made for Sinaloa is that 59.65 m3 of methane could be obtained per year, which is equivalent to $2.25 million per year. All the information generated serves as a precedent for large-scale technical and economic feasibility studies. All these studies will allow the integral use of agricultural industry waste, mainly in rural communities, which will also improve the population's quality of life. Keywords: methane yield, biofuel, agricultural wastes management, methane, Upflow Anaerobic Sludge Blanket, carbon/nitrogen ratio

Dynamic and Energetic Characteristics Comparison of a Tri-Stable Vibration Absorber and Energy Harvester Using Different Permanent Magnet Arrays

In this paper, it has been demonstrated that the tri-stable energy harvesters are more efficient than the bi-stable and mono-stable harvesters in energy harvesting. The oscillators of energy harvesters can be designed as a vibration absorber to attenuate the vibration of the primary system. This paper presents a combined vibration absorber and energy harvester (VAEH) system for simultaneous vibration control and energy harvesting, and the dynamic performances of the VAEH with two magnet arrays of the same geometric parameters, but opposite polarity external magnets, are studied. The mathematical model of the tri-stable VAEH is established, by which the dynamic and energetic characteristics of the VAEH system are obtained. It is found that the potential barrier and potential well depth of the repulsive magnet array are greater than the attractive one, reducing the voltage harvesting efficiency under harmonic and impulsive excitation. Both the amplitude and frequency of excitation are crucial to the dynamic response of the VAEH system. The attractive VAEH performs better than the repulsive VAEH in vibration suppression, especially for high impulse input. From the frequency response of the system, the vibration of the primary system is shown to be magnified at certain frequencies. The magnified primary system vibration and the harvested voltage can be attenuated by increasing the VAEH damping, which is a critical parameter to balance the weight of vibration suppression and energy harvesting. The attractive VAEH designed in this paper performs better than the repulsive one in vibration suppression and energy harvesting.

The energetic, exergetic, and mechanical comparison of two structurally optimized non-concentrating solar collectors for intermediate temperature applications

The highly efficient non-concentrating solar collector is a key component for increasing solar energy penetration at the district level, thereby achieving the “carbon neutrality” goal. The non-concentrating vacuum-type solar collector used for intermediate temperature (100–200 °C) applications is a promising technology that has not been sufficiently explored. In this paper, two structurally optimized non-concentrating solar collectors have been meticulously analyzed from the perspective of structure, energy, exergy, surface stress, etc. Firstly, an outdoor experiment is executed to exhibit their thermodynamic behavior. Thermal resistance networks before and after their structural optimization are formed and the results indicate the thermal resistance that impedes solar collector heat loss has been enhanced by 3.83 and 4.17-fold, respectively. Next, energy and exergy flow charts are established to explain the thermal performance difference and the solar energy conversion in their respective internal components. Finally, the potential room for performance enhancement is further studied via the advanced exergy analysis method which reveals that the exergy destruction can be reduced by 17.74% and 13.90%, respectively. The results are essential for the further development of non-concentrating solar collectors in intermediate temperature applications, and it is also instrumental to realizing the decarbonization in district energy supplements.

Inhibition of the RNA-dependent RNA Polymerase of the SARS-CoV-2 by Short Peptide Inhibitors

The rapid proliferation of SARS-CoV-2 in COVID-19 patients has become detrimental to their lives. However, blocking the replication cycle of SARS-CoV-2 will help in suppressing the viral loads in patients, which would ultimately help in the early recovery. To discover such drugs, molecular docking, MD-simulations, and MM/GBSA approaches have been used herein to examine the role of several short ionic peptides in inhibiting the RNA binding site of the RNA-dependent RNA polymerase (RdRp). Out of the 49 tri- and tetrapeptide inhibitors studied, 8 inhibitors were found to bind RdRp strongly as revealed by the docking studies. Among these inhibitors, the Ala1-Arg2-Lys3-Asp4 and Ala1-Lys2-Lys3-Asp4 are found to make the most stable complexes with RdRp and possess the ΔGbind of -17.41 and -14.21 kcal/mol respectively as revealed by the MD and MM/GBSA studies. Hence these peptide inhibitors would be highly potent in inhibiting the activities of RdRp. It is further found that these inhibitors can occupy the positions of the nucleotide triphosphate (NTP) insertion site, thereby inhibiting the replication of the viral genome by obstructing the synthesis of new nucleotides. Structural and energetic comparisons of these inhibitors with Remdesivir and similar nucleotide drugs show that these peptides would be more specific and hence may act as promiscuous antiviral agents against RdRp.

Energetic and exergetic performance comparison of an experimental automotive air conditioning system using refrigerants R1234yf and R134a

In this study, the energetic and exergetic performance merits of an automotive air condition-ing (AAC) system using R134a and R1234yf have been investigated. For this aim, a laboratory AAC system was developed and equipped with devices for mechanical measurements. The refrigeration circuit of the system mainly had an evaporator, condenser, liquid receiver, fixed capacity compressor, and thermostatic expansion valve. The tests were performed by changing the compressor speed and air stream temperatures incoming the condenser and evaporator. Based on energy and exergy analysis, various performance parameters of the AAC system for both refrigerants were determined and presented in comparative graphics. It was found that R1234yf resulted in 0.4–10.9% lower refrigeration capacity, 5.5–11.6% lower COP, and 4.7–16.1°C lower compressor discharge temperature, while yielding 9.3–22.3% higher refrig-erant mass flow rate and 1.1–3.5°C higher conditioned airstream temperature in comparison to R134a. Moreover, the components of the R1234yf system usually destructed more exergy, and the total exergy destruction rate per unit refrigeration capacity of the R1234yf system was 4.1–15.3% greater than that of the R134a one.