External Energy Supply Research Articles

Modeling of biodiesel production in algae cultivation with anaerobic digestion (ACAD)

This study presents a model of an ecotechnology that combines algae cultivation with anaerobic digestion in order to recycle nutrients and to reduce the need for external energy. The concept is to convert organic waste into several products, such as electricity, biodiesel and organic fertilizer. It is labeled as the ACAD biorefinery. The simulation model of the ACAD biorefinery proved itself to be a powerful tool for understanding the symbioses and dynamics of the system, and therefore also a good tool for reaching political decisions. The model shows that the ACAD biorefinery could be totally independent of external energy supplies. Energy calculations indicate that more energy can be produced by combining the algae cultivation and anaerobic digestion processes. For every unit of energy entering the system in feedstock, 0.6 units of energy are exported as either biodiesel or electricity. The exported electricity accounts for approximately 30% of the total exported energy, while the remaining 70% is exported as biodiesel. By producing its own energy, the biorefinery improves its renewability and level of carbon neutrality.

Enhanced potassium selectivity in a bioinspired solid nanopore

Biological ion channels present unique ionic properties. They can be highly permeable to ions, while selecting only one type of ions, without external energy supply. An important research field has been developed to transfer these properties to solid state nanoporous membranes in order to develop artificial biomimetic nanofilters. One of the promising ways to develop biomimetic structures is based on the direct insertion of the gramicidin A, i.e. an ionic channel, inside a nanopore. Experiments have recently proved the feasibility of such a hybrid membrane with very interesting results regarding the ionic selectivity. Here, we propose to interpret these experiments using theoretical molecular dynamic simulations which allow us to analyze more profoundly the structures of the proteins confined inside the nanopore and the relation between their conformation and the observed ionic properties.

PWM Design for Active Suspension without External Energy Supply Based on LQG Control

A PWM controller is designed for the active suspension without external energy supply (ASWEES) using the LQG control method. Based on the quarter-vehicle ASWEES model, Energy flow equation between the suspension and the accumulator with a 2 kW load was deduced and a PWM controller was designed. When 200Hz solenoid valves were adopted, the carrier frequency and series value of the carrier signal were set as 40 and 5 respectively. Simulation results show the suspension quadratic performance index of ASWEES decreases 24.97% than that of the passive suspension. The passive suspension consumes 2.211kW power, but ASWEES reclaims energy of 2 kW.

Criterial Analysis of Nonlinear Regimes of Transonic Flow Around the Airfoils with A Pulse-Periodic Source of Energy

The paper summarizes our data regarding the energy controlling of the transonic flow. The criterial analysis of the regimes of flow which is formed around the airfoils with an external pulse-periodic energy supply was performed. We selected four criteria, which belong to the class of criteria homochronicity. They are determined by the relations between the period of the energy supply, the rate of gas flow, the velocity of propagation of small disturbances and distances from the beginning or the end zone of energy supply to the position of the closing shock in the undisturbed flow, or the size of the zone of energy. It was shown that the conditions for the forming of the nonlinear regime can be described in terms of the entered criteria of homochronicity. We also obtained estimates for the minimum energy at which the effect of nonlinear interaction is possible, as well as the time of formation of the periodic mode. It was found that the nonlinear effect predominantly has gas-dynamic nature. It was shown that the results of numerical modeling are in agreement with the criterial estimates

Plutonium-238

Ventricular assist devices emerged as a widely used modality for treatment of end-stage heart failure; however, despite significant advances, external energy supply remains a problem contributing to significant patient morbidity and potential mortality. One potential solution is using the nuclear radioisotope Plutonium-238 as a power source. Given its very high energy density and long half-life, Plutonium-238 could eventually allow a totally intracorporeal ventricular assist system that lasts for the patient's lifetime. Risks, such as leakage and theft identified decades ago, still remain. However, it is possible that newer technologies could be used to overcome the system complexity and unreliability of the previous generations of nuclear-powered mechanical assist systems. Were it not for the remaining safety risks, Plutonium-238 would be an ideal energy source for this purpose.

Controlling of the Streamline of Elements of the Airplane by Means of the External Energy Supply

The studies of acting of pulsed-periodic energy supply on the transonic flow regimes of streamline of the body of revolution were performed for different models of the energy source. The possibility of a significant restructuring of the flow, which can serve as a basis for effective control of streamline of as a whole aircraft and its components was demonstrated

Direct Observation of the Uptake of Outer Membrane Proteins by the Periplasmic Chaperone Skp

The transportation of membrane proteins through the aqueous subcellular space is an important and challenging process. Its molecular mechanism and the associated structural change are poorly understood. Periplasmic chaperones, such as Skp in Escherichia coli, play key roles in the transportation and protection of outer membrane proteins (OMPs) in Gram-negative bacteria. The molecular mechanism through which Skp interacts with and protects OMPs remains mysterious. Here, a combined experimental and molecular dynamics simulation study was performed to gain the structural and dynamical information in the process of OMPs and Skp binding. Stopped-flow experiments on site specific mutated and labeled Skp and several OMPs, namely OmpC, the transmembrane domain of OmpA, and OmpF, allowed us to obtain the mechanism of OMP entering the Skp cavity, and molecular dynamics simulations yielded detailed molecular interactions responsible for this process. Both experiment and simulation show that the entrance of OMP into Skp is a highly directional process, which is initiated by the interaction between the N-terminus of OMP and the bottom “tentacle” domain of Skp. The opening of the more flexible tentacle of Skp, the non-specific electrostatic interactions between OMP and Skp, and the constant formation and breaking of salt bridges between Skp and its substrate together allow OMP to enter Skp and gradually “climb” into the Skp cavity in the absence of an external energy supply.

Comparative analysis of the influence of various models of energy supply on the wave drag of an airfoil

A comparative analysis of the efficiency of various models for the external energy supply to airfoil in transonic flight regimes has been carried out. It is established that a decrease in the wave drag of the airfoil is independent of the method of energy supply and is entirely determined by its magnitude. Particular features of a model only influence the local flow characteristics.

Experimental investigation of the methods of energy supply to the external surface of models of flying vehicles

The results of investigation of the effects of external supply of energy to the wind tunnel models at the Mach number M=5 are presented. The energy supply has been modeled by a light gas (helium) supply to the models. The loads have been measured by wind-tunnel balance. It is obtained that at small angles of attack the lift increment under the external supply of energy occurs without an increase in drag and under some conditions is more efficient than the lift increase by means of higher engine thrust under the same energy supply to it. The similarity criterion (“influence coefficient”) is proposed to relate the wind tunnel results to full-scale conditions. Based on the fact that the application of hot hydrogen is the most reasonable for the external supply of energy under full-scale conditions, the aspects of accelerating its ignition and combustion at low temperatures are investigated. It is shown that addition into the hydrogen of its atoms and activated molecules by passing the hydrogen through a glow-discharge zone makes it possible to implement ignition at a temperature of ∼300 K. Without such a treatment, ignition occurs at a temperature of ∼900 K.

Treatment of the Lead Waste Water with Electrochemical Process

Industrial waste water with high levels of lead has serious threat to human health and other organisms. Power generation methods were used for recycling of lead. Some factors such as temperature,power generation time,the anode material, type and concentration of anode area solution on the power generation process were studied to find the optimal process parameters.The experimental results show that:in the optimum conditions,the recovery rate of lead was more than 90% and the lead concentration in waste water has reached the discharge standard. This method does not produce by-products of environmental pollution in the power generation process and needn’t external supply of energy but produce certain energy. So it is a green chemistry technology.

Material Capacity: Embedded Responsiveness

AbstractMost attempts towards climate‐responsive architecture rely heavily on elaborate technical equipment superimposed on otherwise inert material constructs. In contrast, natural systems embed all the responsive capacity in the structure of the material itself. In this article, Achim Menges and Steffen Reichert present the development of biomimetic responsive material systems that require neither the supply of external energy nor any kind of mechanical or electronic control. They introduce their research on physically programming the humidity‐reactive behaviour of these systems, and explain the possibilities this opens up for a strikingly simple yet truly ecologically embedded architecture in constant feedback and interaction with its surrounding environment. Copyright © 2012 John Wiley & Sons, Ltd.

Role of AMPK-mTOR-Ulk1/2 in the Regulation of Autophagy: Cross Talk, Shortcuts, and Feedbacks

Living cells are adaptive self-sustaining systems. They strictly depend on the sufficient supply of oxygen, energy, and nutrients from the outside in order to sustain their internal organization. However, as autonomous entities they are able to monitor and appropriately adapt to any critical fluctuation in their environment. In the case of insufficient external nutrient supply or augmented energy demands, cells start to extensively digest their own interior. This process, known as macroautophagy, comprises the transport of cytosolic portions and entire organelles to the lysosomal compartment via specific double-membrane vesicles, called autophagosomes. Although extensively upregulated under nutrient restriction, a low level of basal autophagy is likewise crucial in order to sustain the cellular homeostasis. On the other hand, cells have to avoid excessive and enduring self-digestion. The delicate balance between external energy and nutrient supply and internal production and consumption is a demanding task. The complex protein network that senses and precisely reacts to environmental changes is thus mainly regulated by rapid and reversible posttranslational modifications such as phosphorylation. This review focuses on the serine/threonine protein kinases AMP-activated protein kinase, mammalian target of rapamycin (mTOR), and unc-51-like kinase 1/2 (Ulk1/2), three interconnected major junctions within the autophagy regulating signaling network.

Operation planning of an independent microgrid for cold regions by the distribution of fuel cells and water electrolyzers using a genetic algorithm

An energy system using a microgrid was examined in this work. The motivations for this study are to promote green energy usage, discuss concerns regarding energy supply during disasters, and improve the efficacy of waste heat usage. To create a society based on clean hydrogen energy, this paper studied the use of a microgrid to supply energy to six houses in a cold region. The proposed microgrid consisted of photovoltaics, a water electrolyzer, a fuel cell, and a heat pump; furthermore, this microgrid was not accompanied by any external energy supply. In this paper, the optimized calculation results obtained from the genetic algorithm (GA) were compared between a system operated using one set of large capacity equipment (a concentrated system) and a system operated using two or more pieces of distributed small-capacity equipment (a distributed system). From this comparison, the operation efficiency of each set of equipment was characterized using the difference in the load factor of the fuel cell and that of the water electrolyzer of each system. Moreover, the optimal capacities of the solar cell, fuel cells, water electrolyzers, and heat pumps while operating an energy-independent microgrid with the concentrated system and the distributed system were presented.

Energy requirements for waste water treatment

The actual mathematical models describing global climate closely link the detected increase in global temperature to anthropogenic activity. The only energy source we can rely on in a long perspective is solar irradiation which is in the order of 10,000 kW/inhabitant. The actual primary power consumption (mainly based on fossil resources) in the developed countries is in the range of 5 to 10 kW/inhabitant. The total power contained in our nutrition is in the range of 0.11 kW/inhabitant. The organic pollution of domestic waste water corresponds to approximately 0.018 kW/inhabitant. The nutrients contained in the waste water can also be converted into energy equivalents replacing market fertiliser production. This energy equivalent is in the range of 0.009 kW/inhabitant. Hence waste water will never be a relevant source of energy as long as our primary energy consumption is in the range of several kW/inhabitant. The annual mean primary power demand of conventional municipal waste water treatment with nutrient removal is in the range of 0.003-0.015 kW/inhabitant. In principle it is already possible to reduce this value for external energy supply to zero. Such plants should be connected to an electrical grid in order to keep investment costs low. Peak energy demand will be supported from the grid and surplus electric energy from the plant can be is fed to the grid. Zero 'carbon footprint' will not be affected by this solution. Energy minimisation must never negatively affect treatment efficiency because water quality conservation is more important for sustainable development than the possible reduction in energy demand. This argument is strongly supported by economical considerations as the fixed costs for waste water infrastructure are dominant.

Mitigation of Wind-Rain-Induced Cable Vibration in Cable-Stayed Bridges: Energy Cost Assessment

The cables in a cable-stayed bridge usually possess low inherent damping and are prone to vibrate by many factors. The wind-rain-induced vibration of the prototype stay cable is a special vibration problem associating with rain and wind. Many methods have been proposed to mitigate wind-rain-induced cable vibrations such as mechanical measures, aerodynamic modification, and control technology. Active control technique has significant control capability because of utilizing the external energy supply but it may not be realistic to large civil engineering structure due to enormous power demand. The two-stage control method has been proposed to control the wind-rain-induced cable vibrations of the prototype stay cable. The studies are carried out to investigate the energy cost features of the control forces as a design guideline.

Coupling of anodic biooxidation and cathodic bioelectro-Fenton for enhanced swine wastewater treatment

A novel bioelectrochemical reactor with anodic biooxidation coupled to cathodic bioelectro-Fenton was developed for the enhanced treatment of highly concentrated organic wastewater. Using swine wastewater as a model, the anode–cathode coupled system was demonstrated to be both efficient and energy-saving. Without any external energy supply to the system, BOD5, COD, NH3-N and TOC in the wastewater could be greatly reduced at both 1.1g COD L−1d−1 and 4.6g COD L−1d−1 of OLR, with the overall removal rates ranging from 62.2% to 95.7%. Simultaneously, electricity was generated at around 3–8Wm−3 of maximum output power density. Based on electron balance calculation, 60–65% of all the electrons produced from anodic biooxidation were consumed in the cathodic bioelectro-Fenton process. This coupled system has a potential for enhanced treatment of high strength wastewater and provides a new way for efficient utilization of the electron generated from biooxidation of organic matters.

Electrogenerative Removal of Cobalt from Sulfate Solutions Using a Batch Reactor

AbstractThe electrogenerative removal of cobalt is conducted in a batch reactor equipped with three‐dimensional electrodes: Reticulated vitreous carbon (RVC) and porous graphite (PG‐25) as cathode materials. In this process, a chemical reaction takes place spontaneously in a divided cell where cobalt is reduced at the cathode and zinc is oxidized to produce electrical energy without an external supply of energy. The results obtained show that RVC serves as a more suitable cathode material than PG‐25 in this system. At optimum conditions, more than 99% of cobalt were removed and recovered in its metallic state after 10 h of operation with an initial 200 mg L−1 Co(II) solution at pH 4 in 0.2 M Na2SO4 and 0.4 M boric acid. Scanning electron microscopy and X‐ray diffraction analyses are performed to study the morphology and crystallographic patterns of cobalt deposits on the cathodes, respectively.

Mechanisms of membrane fouling during ultra-low pressure ultrafiltration

Gravity-driven, dead-end ultrafiltration of surface water, performed at ultra-low pressures without backflushing, cross-flow or chemical cleaning, results in flux stabilization during extended periods of time. This principle can be used for direct ultrafiltration of surface water without an external energy supply and low maintenance for decentralized drinking-water treatment. Here we investigate the mechanisms of membrane fouling and flux stabilization during gravity-driven, ultra low-pressure UF (ULP-UF). The impact of natural organic matter on the structure and resistance of the fouling layer is studied for different types of water, namely river water, pre-treated river water, river water with addition of sodium azide, aerobic diluted wastewater, diluted wastewater with a low dissolved oxygen content and river water spiked with humic acids or kaolin. Our results show that the deposition of non-dissolved material, biologically induced structural changes in the fouling layer and development of irremovable fouling are three major processes determining the fouling and flux stabilization in ULP-UF. The biologically induced structural changes in the fouling layer lead to heterogeneous structures and channel networks there and cause a decrease of the specific resistance of this layer over time. Flux stabilization occurs when the decrease of the resistance due to structural changes in the fouling layer balances the increase of resistance due to deposition and irremovable fouling.

The European Foreign Energy Efficiency Policy: Securing External Energy Supply in a Carbon-Constrained World

The European Foreign Energy Efficiency Policy: Securing External Energy Supply in a Carbon-Constrained World

Controlling Aerodynamic Characteristics of High-Velocity Airfoils by External Energy Supply

The influence of pulsed-periodic (proportional to gas density) energy supply on the aerodynamic characteristics of high-velocity airfoils was studied. The value of the period of the energy supply was varied. The influence of viscosity in the boundary layer approximation has been taken into consideration as well