Energetic Behavior Research Articles

Physiological and behavioral variation by urbanization and climate in an urban-tolerant toad

The distribution of a species is best understood by examining the organism-environment interaction. Climate and anthropogenic habitat degradation, including urbanization, are salient features of the environment that can limit species distributions, especially for ectotherms. Comparative studies of the capacity of individuals to cope with rapid environmental change can help us understand the future success or failure of local populations or even the species. Studies of the glucocorticoid stress response are commonly used to understand how species cope with environmental stressors. Glucocorticoids modulate many aspects of physiological homeostasis including changes in energetic allocation and behavior. In a time of global amphibian decline the Gulf Coast Toad (Incilius nebulifer) is increasing its distribution and abundance. To understand how this species deals with thermal and urban stressors, we studied glucocorticoid regulation, hop performance, and lipid storage in I. nebulifer juveniles across nine populations that differed in average annual temperature and level of imperviousness (as an indication of urbanization). We measured corticosterone release rates at baseline, during agitation stress, and during recovery; then measured locomotor performance and whole-body lipids. We tested if I. nebulifer in hotter temperatures and more urbanized habitats exhibits elevated baseline corticosterone levels and either a reduced corticosterone stress response (“stress resistance” hypothesis) or quick post-stress recovery by negative feedback (“on again, off again” hypothesis). We also tested whether they exhibit reduced fat stores and decreased locomotor performance as costs of dealing with thermal and urban stressors. We found that I. nebulifer showed elevated baseline and agitation (stressed-induced) corticosterone release rates, and higher lipid storage with increasing urbanization. Climate had quadratic effects on these traits, such that populations living at the lowest and highest temperatures had the lowest corticosterone release rates and lipid stores, and the highest hop performance was observed in the least urbanized site at the warmest climate. Additionally, the rate of glucocorticoid recovery after agitation (negative feedback) decreased with increasing temperature and increased with increasing urbanization. These results indicate that I. nebulifer follows the “on again, off again” hypothesis in an adaptive pattern, which may help them cope with environmental change in terms of urbanization and climatic differences.

Energetic scaling behavior of patterned epithelium

Cellular monolayers display various degrees of coordinated motion ranging from the small scale of just a few cells to large multi-cellular scales. This collective migration carries important physical cues for creating proper tissue morphology. Previous studies have demonstrated that the energetics of the epithelial monolayer show a linear variation with time in conjunction with an arrest in monolayer motion after confluency. However, little is known about how the energetics of monolayer development are affected by confined geometries. Here, we demonstrate that micropatterned epithelial monolayers display a non-linear change in energetic variables, which coincides with the large-scale coordination of migration. This non-linear scaling behavior was further seen to be associated with the biased alignment of cells and cell–cell adhesion. These findings provide a new understanding of how developing epithelia may be impacted by different conditions in vivo.

A novel comparison of southern sea otter (Enhydra lutris nereis) fur buoyancy across ontogeny.

Sea otters are extremely positively buoyant and spend most of their time resting at the water surface. It is understood that some of this buoyancy comes from the air layer that sea otters maintain in their pelage, with the lungs providing an additional source of positive buoyancy. Past studies have investigated the fur buoyant force in adult sea otters; however, little is known about the fur buoyant force in younger age classes. This study compared ontogenetic changes in the fur buoyant force of southern sea otter (Enhydra lutris nereis) pelage. We measured the fur buoyant force of pelt samples, scaled that to the whole animal, and calculated mass-specific fur buoyant force for six age classes: neonates (<1 month), small pups (1-2 months), large pups (3-5 months), juveniles (6months-1 year), subadults (1-3 years) and adults (4-9 years). Each pelt sample was measured under three conditions: control, oiled and washed with Dawn® dish soap. Oiled and washed pelts had a lower fur buoyant force compared with the control pelts across all age classes. When oiled, the air layer of the pelt is ruined and no longer provides sufficient positive buoyancy. Pelts washed with Dawn® had higher variability in buoyant force compared with other conditions, and the air layer was not restored consistently. When we scaled up, we found that younger age classes were more buoyant because of their larger surface area to volume ratio. These differences in buoyancy may underlie variations in energetic costs and behavior among sea otters across development.

A facile and effective strategy for modifying combustion of Zr/KClO4 via adding Si

As a commonly applied ignition composition, Zr/KClO4 has attracted various interests and plenty of efforts have been made to improve the combustion performance. In this study, Si nanoparticles were incorporated into Zr/KClO4 by sonication. Around 2.5× peak pressure and 9.2× reactivity were achieved by Si/50%Zr/KClO4 when compared to Zr/KClO4. In addition, the peak pressure and pressurization rate of Si/Zr/KClO4 ternary systems are all superior to ones of both Zr/KClO4 and Si/KClO4 binary systems. The synergetic effect of Si/Zr/KClO4 is a combination of shorter ignition delay of Zr/KClO4 and more gas production of Si/KClO4, which is also reflected on the higher flame propagation rate of Si/Zr-based thermites than composites with pure Si or Zr as the fuel. Meanwhile, the heat release during the redox reaction has been measured. The results show ∼700–1000 J/g higher energy release than Zr/KClO4, and higher combustion efficiency can be attained by ternary systems than binary ones. Thus, adding Si powders is an effective way to improve the energetic behavior of Zr/KClO4 ignition composition, and Si/Zr/KClO4 ternary composites can be a promising candidate for application in pyrotechnics.

Interaction of anionic dye ethyl orange and cationic CnTAC surfactants: A multi technique investigation

This research presents the application of electrical conductivity measurements to ascertain the critical micelle concentration (CMC) values for N-alkyltrimethylammonium chloride surfactants (CnTAC; with alkyl chain lengths of n = 12, 14, 16, and 18). Complementary spectrophotometric analysis was conducted to probe the interactions between CnTAC series and Ethyl Orange (ETO), an anionic dye. Applying the Benesi-Hildebrand and Scott equations, we evaluated the binding constant (Kb) of the cationic micelles’ interaction with ETO, which in turn facilitated calculations of Gibb’s free energy (ΔG°) changes. These calculations provided insight into the binding affinity of ETO to the micelles. Our findings suggest that the interaction between ETO and CnTAC is contingent on the surfactant concentration, with higher concentrations leading to a disassociation of the ETO-CnTAC complex and a reduction in ETO adsorption. Notably, the alkyl chain length within CnTAC molecules critically affects various properties, including ΔG°, CMC, and other thermodynamic parameters that determine the surfactant’s energetic behavior. The study underscores the importance of the alkyl chain length in dictating the interaction dynamics and properties of CnTAC surfactants. A trend was observed where longer alkyl chains lead to increased Kb values and reductions in both CMC and ΔG°, enhancing dye solubilization and interaction spontaneity. The affinity sequence of ETO to the micelles, influenced by alkyl chain length, was found to be C12TAC < C14TAC < C16TAC < C18TAC.

Electro-mechanical modeling and identification of the UR5 e-series robot

Abstract Collaborative robotics is a field of growing industrial interest, within which understanding the energetic behavior of manipulators is essential. In this work, we present the electro-mechanical modeling of the UR5 e-series robot through the identification of its dynamics and electrical parameters. By means of the identified robot model, it is then possible to compute and optimize the energy consumption of the robot during prescribed trajectories. The proposed model is derived from data acquired from the robot controller during bespoke experimental tests, using model identification procedures and datasheet provided by manipulator, motors, and gearbox manufacturers. The entire procedure does not require the use of any additional sensor, so it can be easily replicated with an off-the-shelf manipulator, and applied to other robots of the same family.

High-pressure intrusion of double salt aqueous solution in pure silica chabazite: searching for cation selectivity

Heterogeneous lyophobic systems (HLSs), i.e. systems composed of a nanoporous solid and a non-wetting liquid, have attracted much attention as promising candidates for innovative mechanical energy storage and dissipation devices. In this work, a new HLS based on a pure silica chabazite (Si-CHA) and a ternary electrolyte solution (KCl + CaCl2) is studied from porosimetric and crystallographic points of view. The combined approach of this study has been fundamental in unravelling the properties of the system. The porosimetric experiments allowed the determination of the energetic behaviour, while high-pressure in situ crystallographic analyses helped elucidate the mechanism of intrusion. The results are compared with those obtained for systems involving the same zeolite but intruded with solutions containing only single salts (CaCl2 or KCl). The porosimetric results of the three Si-CHA systems intruded by simple and complex electrolyte solutions (KCl 2 M, CaCl2 2 M and the mixture KCl 1 M + CaCl2 1 M) suggest that the intrusion pressure is mainly influenced by the nature of the cations. The CaCl2 2 M solution shows the highest intrusion pressure and KCl 2 M the lowest, whereas the mixture KCl 1 M + CaCl2 1 M is almost in the middle. These differences are probably related to the higher hydration enthalpy and Gibbs energy of Ca2+ compared with those of K+. It has been demonstrated that partial ion desolvation is needed to promote the penetration of the species, and a higher solvation energy requires higher pressure. The `intermediate' value of intrusion pressure shown by the complex electrolyte solution arises from the fact that, statistically, the second/third solvation cation shells can be assumed to be partially shared between K+ and Ca2+. The stronger interaction of Ca2+ with H2O molecules thus also influences the desolvation of K+, increasing the pressure needed to activate the process compared with the pure KCl 2 M solution. This is confirmed by the structural investigation, which shows that at the beginning of intrusion only K+, Cl− and H2O penetrate the pores, whereas the intrusion of Ca2+ requires higher pressure, in agreement with the hydration enthalpies of the two cations.

Probing Non-Covalent Interactions through Molecular Balances: A REG-IQA Study.

The interaction energies of two series of molecular balances (1-X with X = H, Me, OMe, NMe2 and 2-Y with Y = H, CN, NO2, OMe, NMe2) designed to probe carbonyl…carbonyl interactions were analysed at the B3LYP/6-311++G(d,p)-D3 level of theory using the energy partitioning method of Interacting Quantum Atoms/Fragments (IQA/IQF). The partitioned energies are analysed by the Relative Energy Gradient (REG) method, which calculates the correlation between these energies and the total energy of a system, thereby explaining the role atoms have in the energetic behaviour of the total system. The traditional "back-of-the-envelope" open and closed conformations of molecular balances do not correspond to those of the lowest energy. Hence, more care needs to be taken when considering which geometries to use for comparison with the experiment. The REG-IQA method shows that the 1-H and 1-OMe balances behave differently to the 1-Me and 1-NMe2 balances because the latter show more prominent electrostatics between carbonyl groups and undergoes a larger dihedral rotation due to the bulkiness of the functional groups. For the 2-Y balance, REG-IQA shows the same behaviour across the series as the 1-H and 1-OMe balances. From an atomistic point of view, the formation of the closed conformer is favoured by polarisation and charge-transfer effects on the amide bond across all balances and is counterbalanced by a de-pyramidalisation of the amide nitrogen. Moreover, focusing on the oxygen of the amide carbonyl and the α-carbon of the remaining carbonyl group, electrostatics have a major role in the formation of the closed conformer, which goes against the well-known n-π* interaction orbital overlap concept. However, REG-IQF shows that exchange-correlation energies overtake electrostatics for all the 2-Y balances when working with fragments around the carbonyl groups, while they act on par with electrostatics for the 1-OMe and 1-NMe2. REG-IQF also shows that exchange-correlation energies in the 2-Y balance are correlated to the inductive electron-donating and -withdrawing trends on aromatic groups. We demonstrate that methods such as REG-IQA/IQF can help with the fine-tuning of molecular balances prior to the experiment and that the energies that govern the probed interactions are highly dependent on the atoms and functional groups involved.

Density functional theory calculations, vibrational spectral analysis and topological analysis of 1-acethyl-2(4-isopropoxy-3-methoxyphenyl) cyclopropane with docking studies

A systematic spectroscopic investigationof 1-acethyl-2(4-isopropoxy-3-methoxyphenyl) cyclopropanewasperformed by utilizing Density functional theory approaches at B3LYP level usingGaussian 09 W software package. The FT-IR and FT-Raman techniques were utilized to assign the spectral properties of the title compound. On the basis of Natural Bond Orbital (NBO) analysis,the transfer of second order perturbation energies and ElectronDensity (ED) from filled lone pairs of Lewis base to unfilled Lewis acid sites wereanalysed. The chemical stability,distribution of energy and energetic behaviour of the compound were calculated from the Highest Occupied and Lowest Unoccupied Molecular Orbital (HOMO-LUMO) Analysis. The nucleophilic and electrophilic locales of the moleculewas perceived by the Molecular electrostatic potential (MEP). NCI investigation gives data around the inter and intra non covalent interlinkages. By using the Multiwavefunction software the topological analysis of ELF and LOL were performed. The chemical reactivity sites were determined by means of the fukui function. The assignments of vibrational spectra were computed using thevibration energy distribution analysis (VEDA). Drug similarityfactors were intended to understand the biological aspects. Vadar software was used to generate the Ramachandran plot. The bioactivity of the title compound was confirmed fromthe molecular docking studies.

Effect of interlayer slipping on the geometric, thermal and adsorption properties of 2D covalent organic frameworks: a comprehensive review based on computational modelling studies.

Two-dimensional covalent organic frameworks (2D-COFs) are a class of crystalline porous organic polymers, consisting of 2D-planar sheets stacked together perpendicularly via noncovalent forces. Since their discovery, 2D-COFs have attracted extensive attention for optoelectronic and adsorption applications. Owing to the layer stacking nature of 2D COFs, various new slipped structures that are energetically favourable can be designed. These interlayer slipped structures are actively responsible for tuning (mostly enhancing) the optoelectronic properties, thermal properties, and mechanical strength of 2D COFs. This review summarizes the effect of interlayer slipping on the energetic stability, electronic behaviour and gas adsorption properties of 2D layered COFs, which is explained through computational modelling simulations. Since computational modelling offers a deep insight into electronic behaviour at the atomic scale, which is potentially impossible through experimental techniques, the introduction and role of computational techniques in such studies have also been described.

Exploring carbon catenoids and their applications for encapsulation of carbon nanostructures.

Carbon nanostructures of various shapes are among materials that have been extensively studied due to their unique chemical and physical properties. In this paper, we propose a new geometry of carbon nanostructures known as molecular carbon catenoid to compare with theoretical catenoid found from minimising the Willmore energy functional. Since applications of this structure include electron and molecular transport, this paper mathematically models the energetic behaviour of an atom and a spherical molecule entering a catenoid using the Lennard-Jones potential and a continuum approach. The suction energy is also obtained to determine the size of catenoid suitable for encapsulation of various structures. Results shown for theoretical catenoid using continuum modelling approach are found to be in good agreement with numerical simulations for molecular carbon catenoid.

Timber-Based Strategies for Seismic Collapse Prevention and Energy Performance Improvement in Masonry Buildings

This study investigates the effectiveness of a range of timber-based solutions for the seismic and energy retrofitting of existing masonry buildings. These solutions are designed not only to prevent structural collapse during earthquakes but also to create integrated interventions that enhance thermo-physical performance and reduce emissions in existing buildings. Various case scenarios were considered and both mechanical and energetic behaviour post-intervention were evaluated. Timber-engineered products serve as foundational components for the retrofit approach, encompassing one-dimensional vertical elements (strong-backs) and various types of panels (cross-laminated timber panels, laminated veneer lumber panels, and oriented strand board panels). The analyzed retrofit techniques share a common principle involving the attachment of these timber-based elements to the building’s wall surfaces through mechanical point-to-point connections. The proposed solutions integrate strong-backs and timber panels with membranes and insulation layers, yielding cohesive, and highly effective interventions. Finite element modeling was employed to analyze the mechanical and thermal responses of the retrofitted walls. A comprehensive comparative analysis of various techniques was conducted to determine the most effective solution for each specific scenario.

Ab initio Modeling of Hydrogen Bonding of Remdesivir and Adenosine with Uridine.

Remdesivir (RDV) emerged as an effective drug against the SARS-CoV-2 virus pandemic. One of the crucial steps in the mechanism of action of RDV is its incorporation into the growing RNA strand. RDV, an adenosine analogue, forms Watson-Crick (WC) type hydrogen bonds with uridine in the complementary strand and the strength of this interaction will control efficacy of RDV. While there is a plethora of structural and energetic information available about WC H-bonds in natural base pairs, the interaction of RDV with uridine has not been studied yet at the atomic level. In this article, we aim to bridge this gap, to understand RDV and its hydrogen bonding interactions, by employing density functional theory (DFT) at the M06-2X/cc-pVDZ level. The interaction energy, QTAIM analysis, NBO and SAPT2 are performed for RDV, adenosine, and their complex with uridine to gain insights into the nature of hydrogen bonding. The computations show that RDV has similar geometry, energetic, molecular orbitals, and aromaticity as adenosine, suggesting that RDV is an effective adenosine analogue. The important geometrical parameters, such as bond distances and red-shift in the stretching vibrational modes of adenosine, RDV and uridine identify two WC-type H-bonds. The relative strength of these two H-bonds is computed using QTAIM parameters and the computed hydrogen bond energy. Finally, the SAPT2 study is performed at the minima and at non-equilibrium base pair distances to understand the dominant intermolecular physical force. This study, based on a thorough analysis of a variety of computations, suggests that both adenosine and RDV have similar structure, energetic, and hydrogen bonding behaviour.

Assessing Statistical Indices for Calibrating Building Performance Simulation Models via Continuous Time Series

In engineering planning practice, building simulation is becoming increasingly crucial for evaluating buildings’ energetic and thermal behaviour. The appropriate application in the form of models that represent reality precisely, therefore, faces the challenge of realistic parameter specification for uncertain BES model properties. Many of them can only be restricted to a probable range of values. Additional knowledge can be obtained for the case of available measurement data via inverse modelling. This approach minimises cost function values representing discrepancies between associated time series (measured and simulated data sets). Much research has been published in this field for energy consumption characteristics. These approaches differ in several aspects from measured continuous physical state quantities. This article applies general cost indices to air temperature measurement series. For isolated effects such as time delay and amplitude attenuation, the impact on the characteristic values is examined, and their response is evaluated. This survey leads to the conclusion that there is no single parameter suitable for identifying all effects, and a combination is recommended. A new proposal is made for such a combined statistical index, and exemplary applied for measured temperature curves from a castle near Potsdam.

Energetic analysis of a magnetic gearbox for small wind turbine

In this paper an energetic analysis for the application of a concentric magnetic gearbox (MG) have been carried out. MGs are able to work without contact to minimize acoustic noise and frictions with the advantage of reducing maintenance and increasing the global efficiency of the system. Concentric MGs are useful to a wide range of industrial applications, including renewable energetic systems and electric vehicles. Preliminary studies about this kind of device have been performed by using Finite Element Method (FEM) 3-D and the resulting data have been applied to build a laboratory prototype able to give the first data in terms of power and torque transmitted. Experimental tests have been carried varying the rpm and obtaining the trend of the efficiency, power and torque transmitted. Moreover, the acquired data have been carried out to analyse the energetic and mechanical behaviour of the magnetic transmission.

MyoPassivity Map: Does Multi-Channel sEMG Correlate With the Energetic Behavior of Upper-Limb Biomechanics During Physical Human-Robot Interaction?

MyoPassivity Map: Does Multi-Channel sEMG Correlate With the Energetic Behavior of Upper-Limb Biomechanics During Physical Human-Robot Interaction?

Anti-aging performance improvement and enhanced combustion efficiency of boron via the coating of PDA

Boron is an ambitious fuel in energetic materials since its high heat release values, but its application is prohibited by low combustion efficiency and oxidization during storage. The polydopamine (PDA) was introduced into boron particles, investigating the impact of PDA content on the energetic behavior of boron. The results indicated that the PDA coating formed a fishing net structure on the surface of boron particles. The heat release results showed that the combustion calorific value of B@PDA was higher than that of the raw boron. Specifically, the actual combustion heat of boron powder in B@10%PDA increased by 38.08%. Meanwhile, the DSC peak temperature decreased by 100.65 °C under similar oxidation rate compared to raw boron. Simultaneously, the B@PDA@AP and B@AP composites were prepared, and their combustion properties were evaluated. It was demonstrated that B@10%PDA@AP exhibited superior performance in terms of peak pressure and burning time, respectively. The peak pressure is 12.43 kPa more than B@AP and burning time is 2.22 times higher than B@AP. Therefore, the coating of PDA effectively inhibits the oxidization of boron during storage and enhances the energetic behavior of boron and corresponding composites.

Energy Renovation of an Old University Building

Old buildings consume a lot of energy and no longer comply with thermalregulations, which creates interior discomfort. Our work consists ofhighlighting the effect of the rehabilitation of the building on energy savings and thermal comfort. The case study is an old building converted into offices.We made a dynamic thermal simulation under TRNSYS 17 to analyze thethermal and energetic behavior of the building. The results obtained afterinsulating the opaque walls and replacing the openings are very conclusive.Surface losses decreased by 72%, the heating power decreased by 67%, andthe air conditioning power decreased by 50%.

Interday Reliability of Upper-limb Geometric MyoPassivity Map for Physical Human-Robot Interaction.

The value of intrinsic energetic behavior of human biomechanics has recently been recognized and exploited in physical human-robot interaction (pHRI). The authors have recently proposed the concept of "Biomechanical Excess of Passivity," based on nonlinear control theory, to construct a user-specific energetic map. The map would assess the behavior of the upper-limb in absorbing the kinesthetic energy when interacting with robots. Integrating such knowledge into the design of pHRI stabilizers can reduce the conservatism of the control by unleashing hidden energy reservoirs indicating a less conservative margin of stability. The outcome would enhance the system's performance, such as rendering kinesthetic transparency of (tele)haptics systems. However, current methods require an offline data-driven identification procedure prior to each operation to estimate the energetic map of human biomechanics. This can be time-consuming and challenge users susceptible to fatigue. In this study, for the first time, we investigate the interday reliability of upper-limb passivity maps in a sample of five healthy subjects. Our statistical analyses indicate that the identified passivity map is highly reliable in estimating the expected energetic behavior based on Intraclass correlation coefficient analysis (conducted on different days and with various interactions). The results illustrate that a one-shot estimate is a reliable measure to be used repeatedly in biomechanics-aware pHRI stabilization, enhancing practicality in real-life scenarios.

Doping HTPB binder with cellulose nitrate: A promising strategy for advanced energetic material applications

This study explored the characteristics of hydroxyl-terminated polybutadiene (HTPB) supplemented with cellulose nitrate (NC), as a high-energy density binder. The effect of NC doping and its content on the chemical structure, morphology, energetic, and thermokinetic behavior of HTPB–NC binder highlighted attractive features such as good compatibility, improved density, homogeneity, and fiber dispersion. Additionally, HTPB–NC exhibited excellent thermal stability with significant energy release and notable chemical reactivity. These interesting properties of the HTPB–NC binder, provide evidence for the excellent synergistic effect between HTPB and NC, which could promote its application in the next generation of energetic propellant formulations.