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The biotechnological exploitation of microorganisms enables the use of metabolism for the production of economically valuable substances, such as drugs or food. It is, thus, unsurprising that the investigation of microbial metabolism and its regulation has been an active research field for many decades. As a result, several theories and techniques were developed that allow for the prediction of metabolic fluxes and yields as biotechnologically relevant output parameters. One important approach is to derive macrochemical equations that describe the overall metabolic conversion of an organism and basically treat microbial metabolism as a black box. The opposite approach is to include all known metabolic reactions of an organism to assemble a genome-scale metabolic model. Interestingly, both approaches are rather successful at characterizing and predicting the expected product yield. Over the years, macrochemical equations especially have been extensively characterized in terms of their thermodynamic properties. However, a common challenge when characterizing microbial metabolism by a single equation is to split this equation into two, describing the two modes of metabolism, anabolism and catabolism. Here, we present strategies to systematically identify separate equations for anabolism and catabolism. Based on metabolic models, we systematically identify all theoretically possible catabolic routes and determine their thermodynamic efficiency. We then show how anabolic routes can be derived, and we use these to approximate biomass yield. Finally, we challenge the view of metabolism as a linear energy converter, in which the free energy gradient of catabolism drives the anabolic reactions. [ABSTRACT FROM AUTHOR]

The question of the expediency of increasing the energy efficiency of a large chemical and oil refining industry by using process heat carriers and raw materials as heaters of vapor compression heat pumps based on systems for recuperating heat process losses is considered. A feature of the energy system under consideration is the provision of the main circuit of the heat pump and its drive from a common source of thermal energy. The influence of the temperature parameters of the consumer of highpotential thermal energy, the source of low-potential thermal energy and the energy efficiency of the main functional elements of the energy system under consideration on the ratio of the amount of generated thermal energy supplied to the consumer to the amount of thermal energy losses used is analyzed. In addition, an assessment is made of the influence of the listed factors on the redistribution of low-potential thermal energy flows between the main circuit of the heat pump and its drive. The presented results reflect the fundamental possibility of increasing the temperature level of process heat carriers and raw materials without significant costs for additional external energy sources. The efficiency of reuse of heat losses in a closed technological cycle depends on the temperature conditions of the consumer and the source of thermal energy in the heat pump cycle, on the connection scheme of the thermal energy source and on the energy efficiency of the equipment used.

The question of the feasibility of increasing the energy efficiency of large chemical and oil refining industries by replacing furnace heaters of process heat carriers and raw materials with vapor compression heat pumps is considered. An analysis of the relationship between the technical configuration of vaporcompression heat pumps, the operating parameters of their operation (determining the value of the energy conversion coefficient) and the ratio of the cost of various energy carriers is carried out. The presented results of a comparative analysis of the energy efficiency of various options for replacing a furnace with a vapor compression heat pump reflect the decisive influence of the technical level and design configuration of a vapor compression heat pump on the choice of the preferred upgrade option. However, a significant difference in commercial energy prices significantly changes the preferred ranking of these options.

We propose a self-powered remote multi-sensing system for traffic sensing which is powered by the collective energy harvested from the mechanical vibration of the road caused by the passing vehicles and from the temperature gradient between the asphalt of the road and the soil underneath. A stacked piezoelectric transducer converts mechanical vibrations into electrical energy and a thermoelectric generator harvests the thermal energy from the thermal gradient. Electrical energy signals from the stacked piezoelectric transducer and the thermoelectric generators are converted into usable DC power to recharge the battery using AC-DC and DC-DC converters working simultaneously. The multi-sensing system comprises an embedded system with a microcontroller that acquires data from the sensors and sends the sensory data to an IoT transceiver which transmits the data as RF packets to an ethernet gateway. The gateway converts the RF packets into Internet Protocol (IP) packets and sends them to a remote server. Laboratory and road-testing results showed over 98% sensory data accuracy with the system functioning solely powered by the energy harvested from the alternative energy sources. The successful maximum transmission distance obtained between the IoT, and the gateway was approximately 1 mile, which is a considerable transmission distance achieved in an urban environment. Successful operation of the self-powered multi-sensing system under both laboratory and road conditions contributes considerably to the fields of energy harvesting and self-powered remote sensing systems. The energy flow chart and efficiency for the steps in the system were found to be mechanical power from vehicles to the energy harvester of 0.25%, stacked PZT transducer efficiency was found to be 37%, and for the TEGs the efficiency is 11%. AC-to-DC and DC-to-DC converters' efficiencies were found to be 90% and 11%. The wireless communication RF transceiver efficiency was found to be 62.5%. [ABSTRACT FROM AUTHOR]

The basic electromechanical system of a floating wave power plant has been developed. Besides generating electricity, the power plant protects coastal structure or individual objects in the open sea. The formation of torque at the shaft of the power station is analyzed. The relationship between the capacitance of the energy store and the volume of the reservoir in the energy concentrator is considered. Models of the system components are developed. The relationship between the power of the electromechanical system's components and the rated power of the power station is determined, for the given operating conditions. [ABSTRACT FROM AUTHOR]

The biotechnological exploitation of microorganisms enables the use of metabolism for the production of economically valuable substances, such as drugs or food. It is, thus, unsurprising that the investigation of microbial metabolism and its regulation has been an active research field for many decades. As a result, several theories and techniques were developed that allow for the prediction of metabolic fluxes and yields as biotechnologically relevant output parameters. One important approach is to derive macrochemical equations that describe the overall metabolic conversion of an organism and basically treat microbial metabolism as a black box. The opposite approach is to include all known metabolic reactions of an organism to assemble a genome-scale metabolic model. Interestingly, both approaches are rather successful at characterizing and predicting the expected product yield. Over the years, macrochemical equations especially have been extensively characterized in terms of their thermodynamic properties. However, a common challenge when characterizing microbial metabolism by a single equation is to split this equation into two, describing the two modes of metabolism, anabolism and catabolism. Here, we present strategies to systematically identify separate equations for anabolism and catabolism. Based on metabolic models, we systematically identify all theoretically possible catabolic routes and determine their thermodynamic efficiency. We then show how anabolic routes can be derived, and we use these to approximate biomass yield. Finally, we challenge the view of metabolism as a linear energy converter, in which the free energy gradient of catabolism drives the anabolic reactions.

This paper is devoted to the determination of the value of the maximum specific power of capacitive electrostatic micromotors based on nanometer working gaps. The motors under consideration were developed earlier. They have the following structure: a metal—thin crystalline ferroelectric layer with a high dielectric constant—a nanometer working gap—a movable electrode. The mechanism limiting the magnitude of the maximum field in the gap have also been determined in previous works. The mechanism is the stripping of atoms from the surface of the movable electrode under the action of electrostatic forces. It was shown that the maximum energy density in the working gap can be as high as 1.6 × 109 J/m3. In the presented paper, a maximum frequency of electromechanical energy conversion as high as 10 MHz is estimated for these motors, with a maximum specific power of 5 × 108 W/kg. The application of the proposed motors for micromachines is discussed.

The supply of energy with the correct parameters to electrical appliances is possible with the use of energy converters. When a direct current is required, rectifier bridges are needed. These can be made using rectifier diodes. The problem of excessive junction temperatures in power diodes, which are used to build rectifier bridges and power converters, was recognized. For this reason, research work was carried out to create a model of a rectifier diode placed on a heat sink and to analyze the heat dissipation from the junction of this diode under forced convection conditions. The results obtained from the simulation work were compared with the results of thermographic temperature measurements. The boundary conditions chosen for the simulation work are presented. A method is also presented that determined the convection coefficient under forced convection conditions. The difference between the simulation results and the results of the thermographic measurements was found to be 0.1 °C, depending on the power dissipated at the junction and the air velocity around the diode. [ABSTRACT FROM AUTHOR]

This paper is devoted to the determination of the value of the maximum specific power of capacitive electrostatic micromotors based on nanometer working gaps. The motors under consideration were developed earlier. They have the following structure: a metal—thin crystalline ferroelectric layer with a high dielectric constant—a nanometer working gap—a movable electrode. The mechanism limiting the magnitude of the maximum field in the gap have also been determined in previous works. The mechanism is the stripping of atoms from the surface of the movable electrode under the action of electrostatic forces. It was shown that the maximum energy density in the working gap can be as high as 1.6 × 109 J/m3. In the presented paper, a maximum frequency of electromechanical energy conversion as high as 10 MHz is estimated for these motors, with a maximum specific power of 5 × 108 W/kg. The application of the proposed motors for micromachines is discussed. [ABSTRACT FROM AUTHOR]

This paper numerically simulates the vortex-induced vibrations of ocean current energy harvester with attached spinning cylinders by using the embedded iterative immersed boundary method.The variations of the hydrodynamic properties(the root-mean-square lift coefficient CL,rms,the mean and root-mean-square drag coefficient CD,mean and CD,rms,and the maximum non-dimensional vibration amplitude Ymax/D) with the energy harvest damping ratio ζharness,the non-dimensional spinning velocity α and azimuthal angle θ of the attached cylinders are investigated.Moreover,the variations of the maximum non-dimensional vibration amplitude Ymax/D with the combined parameter α/θ are further investigated.A set of formula is presented by using the curve fitting method.The variations of the coefficients in the formula with influencing parameters are discussed qualitatively. [ABSTRACT FROM AUTHOR]

The nonlinear energy sink (NES) has been presented in the past two decades. Although it has very broad applications, some inherent limitation of the traditional NES is inevitable, such as relatively high energy threshold. This paper proposes a new NES with one-way energy converter (EC), which is realized by an asymmetric bi-linear element. The Runge–Kutta method is used to solve the governing equations of the traditional NES; the EC-NES and the reference configuration and the target energy transfer (TET) efficiency are compared. Numerical evidence confirms that the bi-linear spring plays a leading role in enhancing the one-way energy absorbing. Obvious vibration suppression of the EC-NES due to the low-to-high frequency conversion is observed, which is much more efficient than the others. In addition, the energy pumping is investigated for unveiling vibration dissipation in EC-NES. These results pave a new road for designing the high-efficient vibration isolator. [ABSTRACT FROM AUTHOR]

The supply of energy with the correct parameters to electrical appliances is possible with the use of energy converters. When a direct current is required, rectifier bridges are needed. These can be made using rectifier diodes. The problem of excessive junction temperatures in power diodes, which are used to build rectifier bridges and power converters, was recognized. For this reason, research work was carried out to create a model of a rectifier diode placed on a heat sink and to analyze the heat dissipation from the junction of this diode under forced convection conditions. The results obtained from the simulation work were compared with the results of thermographic temperature measurements. The boundary conditions chosen for the simulation work are presented. A method is also presented that determined the convection coefficient under forced convection conditions. The difference between the simulation results and the results of the thermographic measurements was found to be 0.1 °C, depending on the power dissipated at the junction and the air velocity around the diode.

Ocean renewable energy, such as wave and tidal energies, is important for energy supply and decarbonization of offshore platforms and ships. However, the intermittent and non-dispatchable nature of wave and tidal energy remains a significant challenge. The hybrid wave-tidal energy conversion presents a potential solution to enhance output power and stability by leveraging their complementary characteristics. This paper reviews the current state of hybrid wave-tidal energy conversion technology, focusing on device design, modeling methods and testing methods. Many current hybrid wave-tidal energy converters (HWTEC) have not considered effective coupling among the modules of sub-systems to maximize efficiency. Modeling and simulation methods are mainly based on studies of single wave or tidal energy conversion, and non-linear system modeling is rare. The assumption of continuous functions in most models can lead to discrepancies from real-life conditions. Advancement of modeling approaches, co-simulation algorithms, and dedicated dry lab and pool tests for HWTEC are desired. While HWTEC is potential for improving ocean energy conversion, addressing key challenges of device design, modeling, testing and economic evaluation are essential for realizing its full potential in contributing to decarbonization. • Wave and tide are compared from the perspective of hybrid energy conversion. • Hybrid wave-tidal energy converters are classified and reviewed. • Analysis methods for hybrid wave-tidal energy converters are summarized. • Technology gaps in hybrid wave-tidal energy conversion are identified. • Potential research directions of hybrid wave-tidal energy conversion are proposed. [ABSTRACT FROM AUTHOR]

Wave energy has the potential to play an important role in the UK's electricity mix in the coming years and it is important to understand the interactions of wave energy converters with the environment before considering them viable alternatives for other technologies. The aim of this study was to identify the environmental impacts of the deployment of the Oyster wave energy converter to the EMEC test site at Orkney, UK over its lifetime across three general categories: resource use, human health and ecological consequences. A full life cycle assessment was performed on two different models of the Oyster wave energy converter: Oyster 1 and Oyster 800. It was found that the latter is a fitting upgrade for its predecessor as it has lower environmental impacts in all categories; however, the high infrastructural needs of the Oyster technology makes its environmental performance worse than most other wave energy converters. Key sustainability indicators for energy converters include carbon footprint and energy payback period, and these were found to be 79 and 57 gCO2 eq/kWh and 45 and 42 months for the Oyster 1 and Oyster 800, respectively. Although these are significantly higher than most estimates for other types of renewable energy converter, the carbon impacts are still significantly lower than for conventional fossil-fuelled power generation. [ABSTRACT FROM AUTHOR]

Abstract Current narrative on biofuels is backed up by a large number of studies published in the scientific literature that address second-generation bioethanol only through a single topic approach, nonetheless in the vast majority of cases transition to this energy carrier is evaluated as a generally 'promising' technology. This paper presents a first attempt in proposing an integrated evaluation of the actual benefits expected from bioethanol in the transport sector, by applying the Multi-Scale Integrated Analysis of Societal and Ecosystem Metabolism (MuSIASEM) to the prospective realization of a local system of bio-refinery in Campania Region (Southern Italy). MuSIASEM is a multi-criteria analysis enabling to deal with the complexity of a territorial energy system. Since the unavoidable intrinsic uncertainty, the study does not focus on predictions, but adopts a strategy of Quantitative Story-Telling about some relevant results underlying the limits and critical issues about the energy converter fabric, the economic profitability, environmental constraints and the questionable concept of marginal land. The findings suggest concluding toward falsification of key points in the current narrative: (i) the system is not an efficient solar energy converter; (ii) it fails to realize many of the expectations for a renewable energy carrier producer; (iii) the contribution to decarbonization strategies is not as high as desired and other environmental impacts could not be neglected; (iv) the very large land requirement is hardly compatible with conversion of truly marginal land in Campania region; (v) compared to alternate land uses it does not seem an actually promising strategy to regain value from rural economy. Graphical abstract Image 1 Highlights • Single topic studies are not useful for comprehension of a territorial biorefinery. • Multi-scale and multi-dimensional approach to face the ambiguity of energy concept. • Performance's comparison of two distinct energy production systems is misleading. • Decarbonization and marginal lands concepts are a simplification of the problem. [ABSTRACT FROM AUTHOR]

The technical surveillance of secondary calibration laboratories accredited according to the ISO/IEC 17025 standard for electrical power and energy at industrial frequency is very important, as these measurements are the basis of the commercial relations between an electricity supplier and a user. An effective technical surveillance requires the execution of inter-laboratory comparisons (ILCs). With them, it is possible to verify the competence of the laboratories and the correctness of the dissemination process from the national standards of power and energy, usually maintained at national metrology institutes, to these laboratories. The paper deals with the ILCs that the National Institute of Metrological Research (INRIM) provided and carried out as reference measurements provider for Italian accredited laboratories for power and energy (active and reactive) at industrial frequency. The ILCs were carried out involving various instrument types and at different uncertainty levels. The 2σ relative uncertainties of the INRIM calibrations ranged from 1.0 × 10−4 to 1.5 × 10−3. The ILCs had satisfactory results confirming the correctness of both the dissemination from INRIM and the accreditation process by the Italian accreditation body for calibration laboratories. [ABSTRACT FROM AUTHOR]

Vortex-induced oscillations offer a potential means to harness hydrokinetic energy even at low current speeds. In this study, we consider a novel converter where a cylinder undergoes angular oscillations with respect to a pivot point, in contrast to most previous configurations, where the cylinder undergoes flow-induced oscillations transversely to the incident free stream. We formulate a theoretical model to deal with the coupling of the hydrodynamics and the structural dynamics, and we numerically solve the resulting nonlinear equation of cylinder motion in order to assess the performance of the energy converter. The hydrodynamical model utilizes a novel approach where the fluid forces acting on the oscillating cylinder are split into components acting along and normal to the instantaneous relative velocity between the moving cylinder and the free stream. Contour plots illustrate the effects of the main design parameters (in dimensionless form) on the angular response of the cylinder and the energy efficiency of the converter. Peak efficiencies of approximately 20% can be attained by optimal selection of the main design parameters. Guidelines on the sizing of actual converters are discussed.

The analysis of electromechanical energy converters based on metal-thin film ferroelectric (with a large specific capacitance)-nanogap-moving electrode structures was performed. It was shown that the density of the energy being converted and its absolute value increase with the decreasing gap value between the surfaces of the ferroelectric and the metallic moving electrode up to nanometer values. The effects limiting the growth of this energy were established, and the limiting value of the energy density transformed in the nanogap of these structures was determined to be about 1.6 × 1010 J/m3, which is 4 orders of magnitude higher than the energy density in inductive converters. The experimental verification of this model based on the data for micromotors fabricated on these structures is given.

Harvesting energy from nature have attracted much attentions especially the direct energy conversion from other power sources (e.g. light, heat, mechanical movement, moisture) into practical electricity. However, many of existing devices always rely heavily on external metal electrodes, and their rigid structure restrains further applications in portable touchless electronics or perceptual artificial skins. Herein, we demonstrate flexible in-plane moisture-electric converter (IPMEC) based on graphene oxide (GO) film for novel touchless interactive platform. An appreciable electric output voltage (~70 mV) and high electrical current density (12 mA cm −2 ) can be autonomously generated with ambient moisture variation on this IPMEC. The planar configuration and integrative laser reduced GO electrodes of IPMEC renders it highly flexibility, and greatly promotes the touchless interface formation between this device and biological moisture sources (e.g., human finger). Based on this, diverse touchless devices have been developed including finger position annunciator for smart artificial skin, touchless switches and even handwriting panel. This work will provide a new pathway for the development of flexible moisture-electric converters and applications in touchless interactive platform for biomimetic or smart electronics. [ABSTRACT FROM AUTHOR]

The applicability of Sea-wave Slot-cone Generator breakwater as a system of energy converter in the southern coasts of Iran is investigated. Several efficient factors simultaneously have been considered, including the period and the significant height of wave, the effective depth, and the hydraulic efficiency. The field data used in this study are those derived from the stationary buoys. Findings reveal that Asaluyeh and Shahid-Beheshti ports are the only places, which might satisfy the required needs. The percentage of hydraulic efficiency achieved, however, is less than what is suggested in the literature as the minimum acceptable level. In other words, the use of Sea-wave Slot-cone Generator breakwater is not financially affordable in the southern coasts of Iran. [ABSTRACT FROM AUTHOR]