Stored Potential Energy Research Articles

Protein Supersaturation Drives Innate Immunity Signaling

Multiple signaling proteins of the human innate immune system execute cell fate decisions by assembling into large macromolecular complexes, known as signalosomes, when stimulated by pathogen- or danger-associated molecules. Recent observations that some signalosome assemblies can perpetuate themselves in prion-like fashion in vivo suggest that their activation -- and the corresponding cell fate decisions -- may be thermodynamically pre-determined. In other words, signalosome assembly is inevitable, but postponed in the absence of stimulation by structurally-encoded nucleation barriers to self-assembly. We explored this hypothesis using DAmFRET, a newly developed flow cytometric assay for prion-like protein phase behavior, to identify nucleation barriers that govern self-assembly by homotypic interaction domains of the death fold, TIR, and RHIM families from over one-hundred human innate immune signaling proteins. We discovered thirty-six proteins with robust prion-like activity, including the major signalosome scaffolding proteins, or “adaptors”. We further demonstrate for a subset of the corresponding full length proteins that nucleation barriers also control the endogenous proteins’ activities in human THP-1 monocytes, and that hyper- and hypo-activating disease-causing mutations respectively decrease or increase the barriers. We provide a logic for prion-like activity in the architecture of innate immune signaling pathways, and conclude that adaptor protein supersaturation functions to store potential energy and then release it upon nucleation for rapid and effectively irreversible switch-like control over innate immunity signaling.

Control of inherited accreted lithospheric heterogeneity on the architecture and the low, long-term subsidence rate of intracratonic basins

Intracratonic basins tend to subside much longer than the timescale predicted by thermal relaxation of the lithosphere. Many hypotheses have been suggested to explain their longevity, yet few have been tested using quantitative thermo-mechanical numerical models, which capture the dynamic of the lithosphere. Lithospheric-scale geodynamic modelling preserving the tectono-stratigraphic architecture of these basins is challenging because they display only few kilometres of subsidence over 1000 of km during time periods exceeding 250 Myr. Here we present simulations that are designed to examine the relative role of thermal anomaly, tectonics and heterogeneity of the lithosphere on the dynamics of intracratonic basins. Our results demonstrate that initial heterogeneity of accretionary continental lithosphere explains long-term subsidence and the arches-basins architecture of Saharan type intracratonic basins at first order. The simulations show that initially heterogeneous lithospheres inherited from accretion are strong enough to resist local isostatic re-equilibration for very long period of time. Indeed, the lateral density variations store potential gravitational energy that is then slowly dissipated by differential erosion and slow vertical movements. For relatively well-accepted coefficient of erosion of 10−6 m2/s, the subsidence last longer than 250 Myr. Extensional tectonic forcing and thermal anomalies both result in an effective strength drop of the lithosphere, which allows a temporal acceleration of local isostatic re-equilibration. Periodic changes in far field tectonic forcing from extension to compression complicate the tectono-stratigraphic architecture (intra-basin arches, sub-basins) introducing stratigraphic unconformities between different neighbouring basins such as the ones observed in North Africa.

Progress towards nanoengineered energetic materials

Given the constraints on typical bond energies and the commonality of final products produced from combustion of CHNO based energetic materials, the possibilities for further increases in stored potential energy and thermodynamic performance from these classes of materials are limited. Thus, modulating the energy release to achieve efficiency and effectiveness for desired applications is of great value. Investigation of nanomaterials as energetic materials began more than twenty years ago with much of the interest to increase reaction rates and reduce sensitivity. During this period, research on energetic nanoparticles was devoted to reducing the loss of energy density with metallic materials due to the naturally occurring oxide passivating layer, managing their high surface area preventing high loadings in solids, minimizing particle-particle interactions making dispersion in the gas-phase difficult, and understanding combustion mechanisms. As an outcome, novel synthesis methods of producing nanocomposites, and new fields of applications, such as micro-pyrotechnics, have developed. Yet, the research community is only beginning to understand how to manipulate and build energetic materials at the nanoscale, and what designs are optimal for desired functions. Furthermore, recognizing the difficulties for increased energy density and reduced sensitivity, the development of multifunctional and smart nanoenergetic materials is currently being researched to enable control of energy release rates and material sensitivity on demand. This research is being advanced by assembly of nanoengineered energetic materials to bulk scales by additive manufacturing, the development and application of combustion diagnostics that resolve nanometer and micron scales, and ab initio quantum chemistry and molecular dynamics calculations. The challenges that have been confronted and the directions of continuing research on nanoenergetics are presented and discussed.

Analysis of a 180-degree U-turn maneuver executed by a hipposiderid bat.

Bats possess wings comprised of a flexible membrane and a jointed skeletal structure allowing them to execute complex flight maneuvers such as rapid tight turns. The extent of a bat's tight turning capability can be explored by analyzing a 180-degree U-turn. Prior studies have investigated more subtle flight maneuvers, but the kinematic and aerodynamic mechanisms of a U-turn have not been characterized. In this work, we use 3D optical motion capture and aerodynamic simulations to investigate a U-turn maneuver executed by a great roundleaf bat (Hipposideros armiger: mass = 55 g, span = 51 cm). The bat was observed to decrease its flight velocity and gain approximately 20 cm of altitude entering the U-turn. By lowering its velocity from 2.0 m/s to 0.5 m/s, the centripetal force requirement to execute a tight turn was substantially reduced. Centripetal force was generated by tilting the lift force vector laterally through banking. During the initiation of the U-turn, the bank angle increased from 20 degrees to 40 degrees. During the initiation and persisting throughout the U-turn, the flap amplitude of the right wing (inside of the turn) increased relative to the left wing. In addition, the right wing moved more laterally closer to the centerline of the body during the end of the downstroke and the beginning of the upstroke compared to the left wing. Reorientation of the body into the turn happened prior to a change in the flight path of the bat. Once the bat entered the U-turn and the bank angle increased, the change in flight path of the bat began to change rapidly as the bat negotiated the apex of the turn. During this phase of the turn, the minimum radius of curvature of the bat was 5.5 cm. During the egress of the turn, the bat accelerated and expended stored potential energy by descending. The cycle averaged total power expenditure by the bat during the six wingbeat cycle U-turn maneuver was 0.51 W which was approximately 40% above the power expenditure calculated for a nominally straight flight by the same bat. Future work on the topic of bat maneuverability may investigate a broader array of maneuvering flights characterizing the commonalities and differences across flights. In addition, the interplay between aerodynamic moments and inertial moments are of interest in order to more robustly characterize maneuvering mechanisms.

Effects of pre-strain on the nanoindentation behaviors of metallic glass studied by molecular dynamics simulations

Nanoindentation simulations have been performed on pre-compressed and pre-stretched Cu64Zr36 metallic glasses (MGs) samples via molecular dynamics methods, to investigate the effects of pre-stress on the mechanical behavior, deformation performance and shear bands forming morphologies of the MG material. The results have shown that pre-tensile stress has a more intuitive “weaken” impact on the mechanical performance of the MG. While for pre-compressive cases, with increasing compressive strain, the pre-stress has a “harden” to “weaken” effects transition. Based on Hertz’s contact, the analysis of simulation results indicated both the stress state of the material and the structural change induced by applied stress contribute to the “harden/weaken” effects. Besides, the shear bands morphologies under indentations are also found to be influenced by the sign and magnitude of the pre-stress. And if the pre-stress is large enough, the shear banding would propagate spontaneously and rapidly, which may result in brittle deforming mode happened in the indentation process. Furthermore, By using the energy analysis method, this plastic to brittle transition is inferred to be connected with the stress state and potential energy stored in the material. If the stored potential energy exceeds the essential forming energy of shear bands, the fracture would happen once local area is triggered by external stress.

Whale jaw joint is a shock absorber.

The non-synovial temporomandibular jaw joint of rorqual whales is presumed to withstand intense stresses when huge volumes of water are engulfed during lunge feeding. Examination and manipulation of temporomandibular joints (TMJs) in fresh carcasses, plus CT scans and field/lab mechanical testing of excised tissue blocks, reveals that the TMJ's fibrocartilage pad fully and quickly rebounds after shrinking by 68-88% in compression (by axis) and stretching 176-230%. It is more extensible along the mediolateral axis and less extensible dorsoventrally, but mostly isotropic, with collagen and elastin fibers running in all directions. The rorqual TMJ pad compresses as gape increases. Its stiffness is hypothesized to damp acceleration, whereas its elasticity is hypothesized to absorb shock during engulfment, allow for rotation or other jaw motion during gape opening/closure, and aid in returning jaws to their closed position during filtration via elastic recoil with conversion of stored potential energy into kinetic energy.

Flight Strategy Optimization for High-Altitude Solar-Powered Aircraft Based on Gravity Energy Reserving and Mission Altitude

High-altitude long-duration (HALE) flight capability is one of the ultimate goals pursued by human aviation technology, and the high-altitude solar-powered aircraft (SPA) is the most promising technical approach to achieve this target as well as wide application prospects. Due to the particularity of the energy system, the flight strategy optimization through the storage of gravity potential energy and other methods is a significant way to enhance the flight and application abilities for the SPA. In this study, a flight strategy optimization model has been proposed for the aim of HALE flight capability, which is based on the gravity energy reserving and mission altitude in practical engineering applications. This integrated model contains the five flight path phase model, the three-dimensional kinematic model, aerodynamic model, solar irradiation model and energy store and loss model. To solve the optimization problem of three-dimensional flight strategy, the Gauss pseudo-spectral Method (GPM) was employed to establish and calculate the optimal target as its advantages in treating process constraints and terminal constraints for the multiphase optimization problem. At last, the flight trajectory optimization with minimal battery mass for Zephyr 7 was studied by the GPOPS with some function files in MATLAB. The results indicate that the Zephyr 7 can reduce the battery mass from 16 kg to 12.61 kg for the day and night cycle flight and missions, which equals to increasing the battery specific energy by 23.1%. Meanwhile, the optimization results also show that the attitude angel may contribute to increasing the energy gained by photovoltaic cells. In addition, this optimized flight strategy brings the possibility of monthly or annual continuous flight for SPA as the simulation date is set to the autumnal day.

Ingenious floral structure drives explosive pollination in Hydrilla verticillata (Hydrocharitaceae).

In explosive pollination, many structures and mechanisms have evolved to achieve high-speed stamen movement. The male flower of the submerged plant Hydrilla verticillata is reported to be able to release pollen explosively some time after leaving the mother plant time, but the mechanism of stamen movement and the related functional structure in this species are unclear. In this study, we observed the male flower structure and pollen dispersal process of H.verticillata. We analysed the stamen movements during the pollen dispersal process and conducted several controlled experiments to study the process of storage and release of elastic potential energy in explosive pollination. When the male flower of H. verticillata is bound to the united bracts, the sepals accumulate elastic potential energy through the expansion of basal extensor cells. After the male flower is liberated from the mother plant, the stamens unfold rapidly with the sepals under adhesion and transfer the elastic potential energy to the filament in seconds. Once stamens unfold to a critical angle, at which the elasticity of the filament just exceeds the adhesion between sepals and anthers, the stamens automatically rebound and release pollen in milliseconds. These results reveal that Catapult-like stamens, spoon-shaped sepals and enclosed united bracts in the spathe together constitute the functional structure in rapid stamen movement of H.verticillata. They ensure that the pollen can be released on the water surface, and thus adapt successfully to the pollen-epihydrophilous pollination.

Study and practical investigations of Nano Supercapacitors

Capacitors are basically defined as a two-terminal electric component which stores potential energy in an electric field. The effect of the capacitor is known as capacitance. Generally, there exists some capacitance exists between any two electrical conductors in proximity in a circuit, a capacitor is a component designed to add capacitance. The capacitor was originally known as a condenser. The physical form and construction of the practical capacitors vary widely. Most capacitors contain two electrical conductors often in the form of metallic plates or surfaces separated by a dielectric medium. A conductor is generally a foil, thin film, sintered bead of metal, or an electrolyte. The nonconducting dielectric acts in order to increase the capacitor's charge capacity. Materials commonly used as the dielectrics include glass, ceramic, paper, plastic film, mica, and oxide layers. In the common world Capacitors are widely used as parts of electrical circuits in many common electrical devices. Unlike normal a resistor, an ideal capacitor does not dissipate energy. But the energy density of the capacitor is very low due to this greater number of capacitors are required to maintain a particular circuit.so to rectify these kinds of problems, we need a device which is more capable to hold the potential energy

Terramechanics Modeling and Grouser Optimization for Multistage Adaptive Lateral Deformation Tracked Robot

A multistage adaptive lateral deformation tracked robot was designed to improve the passing ability of field robots. The designed robot can change its width under the combined action of space barrier constraint and internal stored elastic potential energy. The lateral sliding friction affected by grouser parameters during lateral deformation is a key factor that determines whether or not the robot can achieve deformation. This study focuses on the track terramechanics and grouser parameter optimization. On the basis of the theory of terramechanics, the interaction of the flexible track lateral movement with the ground model and traction model was established. Taking the requirement of traction as the constraint condition and the minimum lateral sliding resistance as the optimization objective, we used the multitarget optimization algorithm (NSGA-II) to optimize and analyze the grouser parameters. Then, the optimal combination of grouser parameters was obtained. Simulation analysis was carried out on RecurDyn software to complete the simulation verification of the lateral force and traction force under different grouser parameters. The correctness of the theoretical model and the optimization of the grouser parameters was verified through prototype experiments.

On the role of compressibility in poroviscoelastic models.

In this article we conduct an analytical study of a poroviscoelastic mixture model stemming from the classical Biot's consolidation model for poroelastic media, comprising a fluid component and a solid component, coupled with a viscoelastic stress-strain relationship for the total stress tensor. The poroviscoelastic mixture is studied in the one-dimensional case, corresponding to the experimental conditions of confined compression. Upon assuming (i) negligible inertial effects in the balance of linear momentum for the mixture, (ii) a Kelvin-Voigt model for the effective stress tensor and (iii) a constant hydraulic permeability, we obtain an initial value/boundary value problem of pseudo-parabolic type for the spatial displacement of the solid component of the mixture. The dimensionless form of the differential equation is characterized by the presence of two positive parameters γ and η, representing the contributions of compressibility and structural viscoelasticity, respectively. Explicit solutions are obtained for different functional forms characterizing the boundary traction. The main result of our analysis is that the compressibility of the components of a poroviscoelastic mixture does not give rise to unbounded responses to non-smooth traction data. Interestingly, compressibility allows the system to store potential energy as its components are elastically compressed, thereby providing an additional mechanism that limits the maximum of the discharge velocity when the imposed boundary traction is irregular in time.

Brittle-ductile transition depth versus convergence rate in shallow crustal thrust faults: Considerations on seismogenic volume and impact on seismicity

Earthquakes occur in the Earth’s crust where rocks are brittle, with magnitude increasing with the volume involved in the coseismic stage. Largest volumes are expected in convergent tectonic settings since thrust fault may be even more than 25 times larger than hypocenter depth. In general, the maximum depth of hypocenters within the crust corresponds to the brittle-ductile transition (BDT). The deepening of the BDT increases the potential seismic volume, hence raising the energy released during an earthquake. Here, by means of 2-D thermo-mechanical modelling dedicated to intraplate thrusts and thrusts within fold-and-thrust belts (shallow crust), the deepening of the BDT depth in convergent settings with variable convergence rates is investigated. Results of models characterized by shallow faults (15°–20° dip) show that BDT depth deepens by 15 km increasing the convergence rate from 1 to 10 cm/yr. Steeper thrust faults (25°–40° dip) show a lower degree of deepening of the BDT (≃5 km) as convergence rate is increased. Calculated BDT depths allow the calculation of maximum seismic volumes involved during thrust earthquakes. Deeper BDT depths obtained assuming higher convergence rates imply larger seismic volumes and an increase of 2 orders of magnitude of the stored potential energy, as effectively observed in nature.

A new type of hydrokinetic accumulator and its simulation in hydraulic lift with energy recovery system

The article presents a model and a simulation study of a new type of hydrokinetic accumulator with increased energy storage density. The basic elements of the accumulator are: a flywheel of variable moment of inertia (due to inflow or outflow of hydraulic fluid) and a variable displacement pump/motor. The first part of the article describes the construction and operation principles of the developed accumulator with three specified work modes. A mathematical model of the presented hydrokinetic accumulator and its simulation in a hydrostatic lift system with energy recovery are given. The results of the numerical simulations carried out during charging and discharging of the accumulator (i.e. values of the stored kinetic and potential energy and chosen working parameters) are presented. It is shown that, due to energy storage and extraction, in both hydrostatic and rotating kinetic domains, charging and discharging may be decoupled from pressure level. Additionally, the accumulator has the ability to control the pressure in the hydraulic system. An example of the control algorithm is also presented in the paper.

Renewable Energy Potentials along the Bay of Bengal due to Tidal Water Level Variation

The projected increase in energy demand coupled with concerns regarding present reliance on fossil fuel and associated environmental concerns had led to increased interest in exploiting renewable energy sources. Among different renewable energy sources, tidal energy is unique and most suitable because of its predictable nature and capability to ensure supply security. Tide consists of both kinetic and potential energy which can be converted to electricity using well-proven technology. The potential energy of tides - the principal focus of the study, is stored due to rise and fall of the sea level. Head difference created due to tidal variation between basin side and sea side of a barrage stores potential energy which is converted into fast-moving water that rotates turbine and generates electricity. Bangladesh with its long coastline has promising prospects of tidal energy resource development. The study focuses on tidal energy resource exploration and exploitation along several competent locations of the Bengal coastline. Tidal records of flood and ebb tide of these locations are analyzed to calculate the potential energy. Finally, available potential techniques of energy extraction are evaluated for annually generated energy estimation. This study investigates the prospect and utilization of tidal energy concept and reviews the possibilities and opportunities of employment of the technology for sustainable development and climate change mitigation in context of Bangladesh.

An index of anomalous convective instability to detect tornadic and hail storms

In this article, the synoptic-scale spatial structures for raising tornadic and hail storms are compared by analyzing the total and anomalous variable fields from the troposphere to the stratosphere. 15 cases of tornado outbreaks and 20 cases of hail storms that occurred in the central United States during 1980–2011 were studied. The anomalous temperature–height field shows that a tornadic or hail storm usually occurs at the boundary of anomalous warm and cold air masses horizontally in the troposphere. In one side, an anomalous warm air mass in the mid-low troposphere and an anomalous cold air mass in the stratosphere are vertically separated by a positive center of height anomalies at the upper troposphere. In another side, an opposite vertical pattern shows that an anomalous cold air mass in the mid-low troposphere and an anomalous warm air mass in the stratosphere are separated by a negative center of height anomalies at the upper troposphere. Therefore, two pairs of adjacent anomalous warm/cold centers and one pair of anomalous high/low centers combining together form a major tornadic or hail storm paradigm, which can be physically considered as the storage of anomalous potential energy (APE) to generate severe weather. To quantitatively measure the APE, we define an index of anomalous convective instability (ACI) which is a difference of integrating temperature anomalies based on two vertically opposite anomalous air masses. The APE transformation to anomalous kinetic energy, which reduces horizontal and vertical gradients of temperature anomalies, produces anomalous rising and sinking flows in the lower-layer anomalous warm and cold air mass sides, respectively. The intensity of ACI index for tornadic storm cases is 1.5 times larger than that of hail storm cases in average. Thus, this expression of anomalous variables is better than total variables used in the traditional synoptic chart and the ACI index is better than other indices to detect potential tornadic and hail storms in order to understand the environmental conditions affecting severe weather in analytical and model output datasets.

Synthesis, structural and high frequency dielectric properties of polypyrrole (PPy)/holmium ferrite composites

Conducting polymers and their composites are receiving considerable attention due to their applications in commercial and domestic appliances based on their electrical, optical and thermal properties. Also the magnetic and conducting properties of ferrite/polypyrrole (PPy) composites have opened a new horizon in multifunctional materials. In the present study, different properties of PPy, holmium substituted ferrite and their composites have been investigated. Prior to that, PPy was prepared by the chemical polymerization method of pyrrole in the presence of FeCl3⋅6H2O. Holmium substituted ferrite Co0.02Ho1.98Fe2O4 was prepared by using co-precipitation technique. The X-ray diffraction (XRD) pattern showed crystalline ferrite phase having an average crystallite size of 27 nm. Composites with different ratios of ferrite and PPy were fabricated using solid state reaction technique. The structural and morphological properties of PPy/Ferrite composites were studied by XRD and scanning electron microscopy (SEM), respectively. Frequency dependent dielectric properties were studied in the range of 1 MHz-3 GHz; the dielectric constant value for composite is higher than that for the holmium ferrite. The higher dielectric constant of the composite indicates that these materials have better ability to store potential energy under the influence of alternating electric field.

The cost of decarbonizing the Canadian electricity system

Canada’s electricity sector is predominantly low-carbon, but includes coal, natural gas, and diesel fuelled power plants. We use a new linear programming optimization model to identify least-cost pathways to decarbonize Canada’s electricity sector. We co-optimize investments in new generation, storage and transmission capacity, and the hourly dispatch of available assets over the course of a year. Our model includes hourly wind speed data for 2281 locations in Canada, hourly solar irradiation data from 199 Canadian meteorological stations, hourly demand data for each province, and inter- and intra-provincial transmission line data. We model the capacity of hydropower plants to store potential energy and respond to variations in renewable energy output and demand. We find that new transmission connections between provinces and a substantial expansion of wind power in high wind locations such as southern Saskatchewan and Alberta would allow Canada to reduce electricity sector emissions at the lowest cost. We find that hydropower plants and inter-provincial trade can provide important balancing services that allow for greater integration of variable wind power. We test the impact of carbon pricing on Canada’s optimal electricity system and find that prices of $80/tonne CO2e render the majority of Canada’s coal-fired plants uneconomic.

Energy capture and storage in asymmetrically multistable modular structures inspired by skeletal muscle

The remarkable versatility and adaptability of skeletal muscle that arises from the assembly of its nanoscale cross-bridges into micro-scale assemblies known as sarcomeres provides great inspiration for the development of advanced adaptive structures and material systems. Motivated by the capability of cross-bridges to capture elastic strain energy to improve the energetic efficiency of sudden movements and repeated motions, and by models of cross-bridge power stroke motions and sarcomere contractile behaviors that incorporate asymmetric, bistable potential energy landscapes, this research develops and studies modular mechanical structures that trap and store energy in higher-energy configurations. Modules exhibiting tailorable asymmetric bistability are first designed and fabricated, revealing how geometric parameters influence the asymmetry of the resulting double-well energy landscapes. These experimentally-observed characteristics are then investigated with numerical and analytical methods to characterize the dynamics of asymmetrically bistable modules. The assembly of such modules into greater structures generates complex, multi-well energy landscapes with stable system configurations exhibiting different quantities of stored elastic potential energy. Dynamic analyses illustrate the ability of these structures to capture a portion of the initial kinetic energy due to impulsive excitations as recoverable strain potential energy, and reveal how stiffness parameters, damping, and the presence of thermal noise in micro- and nano-scale applications influence energy capture behaviors. The insights gained could foster the development of advanced structural/material systems inspired by skeletal muscle, including actuators that effectively capture, store, and release energy, as well as adaptive, robust, and reusable armors and protective devices.

A Novel Speed–Density Relationship Model Based on the Energy Conservation Concept

This paper makes a basic assumption that energy conservation exists, between psychological potential and a vehicle's kinetic energy, in the driver's psychological field based on the driver's mental activities. A virtual spring is used to describe the storage and release of psychological potential energy. Under the aforementioned conditions, we established a macroscopic traffic flow model with conservation law. Each parameter in the new model is physically meaningful and explicit. Additionally, the model can fit field data consistently well, both in free-flow and congested situations. The results of this paper prove the rationality of the energy conservation concept in traffic flow, which improves the understanding of traffic flow and provides a new theoretical foundation.

The Cost of Decarbonizing the Canadian Electricity System

Canada’s electricity sector is predominantly low-carbon, but includes coal, natural gas, and diesel fuelled power plants. We use a new linear programming optimization model to identify least-cost pathways to decarbonize Canada’s electricity sector. We co-optimize investments in new generation, storage and transmission capacity, and the hourly dispatch of available assets over the course of a year. Our model includes hourly wind speed data for 2281 locations in Canada, hourly solar irradiation data from 199 Canadian meteorological stations, hourly demand data for each province, and inter- and intra-provincial transmission line data. We model the capacity of hydropower plants to store potential energy and respond to variations in renewable energy output and demand. We find that new transmission connections between provinces and a substantial expansion of wind power in high wind locations such as southern Saskatchewan and Alberta could allow Canada to reduce electricity sector emissions at the lowest cost. We find that hydropower plants and inter-provincial trade can provide important balancing services that allow for greater integration of variable wind power. We test the impact of carbon pricing on Canada’s optimal electricity system and find that prices of $80/tonne render Canada’s coal-fired plants uneconomic.