Reciprocity Relations Research Articles

Power balance analysis of nonperiodic structural components from a model converted from FEM to SEA.

Using Statistical Energy Analysis (SEA) to characterize the power flow within a vibroacoustic system is a challenging task when the subsystems have irregular shape and complex construction. Retrieving analytical solutions for the ordinary SEA parameters is nearly impractical without restricting simplifications and periodicity is usually not exploitable due to the lack of repetition patterns. A promising option to perform the power balance for such cases is to filter part of the information contained in a Finite Element Method (FEM) model of the system, in order to convert it into a SEA model. In this paper, the Lorentzian Frequency Average and the Nonparametric Random Matrix Theory are applied to randomize the dynamic stiffness matrix of the FEM components from a system of industrial application. The obtained direct field dynamic stiffness matrices are employed along the diffuse field reciprocity relationship as a general framework to determine the energetic content of each component. The results obtained with this procedure are evaluated against the ones from classical SEA and Monte Carlo techniques.

Coherence theory for electromagnetic, planar, PT-symmetric sources

A class of planar, electromagnetic, stationary optical sources obeying PT-symmetry conditions is introduced. On deriving a set of Fourier reciprocity relations obeyed by such sources and far fields they radiate, we discover that the latter can only have linear polarization states.

Some identities and reciprocity relationsof unipoly-Dedekind type DC sums

Dedekind type DC sums and their generalizations are defined in terms of Euler functions and their generalization. Recently, Ma et al. (Adv. Differ. Equ. 2021:30 2021) introduced the poly-Dedekind type DC sums by replacing the Euler function appearing in Dedekind sums, and they were shown to satisfy a reciprocity relation. In this paper, we consider two kinds of new generalizations of the poly-Dedekind type DC sums. One is a unipoly-Dedekind type DC sum associated with the type 2 unipoly-Euler functions expressed in the type 2 unipoly-Euler polynomials using the modified polyexponential function, and we study some identities and the reciprocity relation for these unipoly-Dedekind type DC sums. The other is a unipoly-Dedekind sums type DC associated with the poly-Euler functions expressed in the unipoly-Euler polynomials using the polylogarithm function, and we derive some identities and the reciprocity relation for those unipoly-Dedekind type DC sums.

Radiometric force on a sphere in a rarefied gas based on the Cercignani–Lampis model of gas–surface interaction

The radiometric force on a sphere due to its thermal polarization in a rarefied gas flow being in equilibrium is investigated on the basis of a kinetic model to the linearized Boltzmann equation. The scattering kernel proposed by Cercignani and Lampis to model the gas–surface interaction using two accommodation coefficients, namely, the tangential momentum accommodation coefficient and the normal energy accommodation coefficient, is employed as the boundary condition. The radiometric force on the sphere, as well as the flow field of the gas around it, is calculated in a wide range of the gas rarefaction, defined as the ratio of the sphere radius to an equivalent free path of gaseous particles, covering the free molecular, transition, and continuum regimes. The discrete velocity method is employed to solve the kinetic equation numerically. The calculations are carried out for values of accommodation coefficients considering most situations encountered in practice. To confirm the reliability of the calculations, the reciprocity relation between the cross phenomena is verified numerically within a numerical error of 0.1%. The temperature drop between two diametrically opposite points of the spherical surface in the direction of the gas flow stream, which characterizes the thermal polarization effect, is compared to experimental data for a spherical particle of Pyrex glass immersed in helium and argon gases.

Beyond Fermi’s golden rule in free-electron quantum electrodynamics: acceleration/radiation correspondence

In this article, we present a unified reciprocal quantum electrodynamics (QED) formulation of free-electron and quantum–light interaction. For electron–light interactions, we bridge the underlying theories of photon-induced near-field electron microscopy, laser-induced particle accelerators, and radiation sources, such as quantum free electron laser, transition radiation and Smith-Purcell effect. We demonstrate an electron–photon spectral reciprocity relation between the electron energy loss/gain and the radiation spectra. This ‘acceleration/radiation correspondence’ (ARC) conserves the electron energy, and photon number exchanged, that is, ΔE/ℏω + Δν q = 0, and in the representation of a quantum electron wavepacket, displays explicit dependence on the history-dependent phase and shape of the wavepacket configuration. It originates from an interaction-induced quantum interference term that is usually ignored in Fermi’s golden rule analyses, but is kept in our combined quantum free electron–photon state formulation. We apply this formulation to both stimulated interaction and spontaneous emission of classical and quantum light by the quantum-featured electrons. The ‘spontaneous’ emissions of coherent states (‘classical’ light) are remarked and squeezed states of quantum light is shown to be enhanced with squeezing. This reciprocal QED formulation has promise for extensions to other fundamental research issues in quantum light and quantum matter interactions.

Simple Processing and Analysis of Flexible III–V Multijunction Solar Cells Using Low‐Temperature Transfer Technology

A simple method is proposed for manufacturing the flexible III–V inverted metamorphic solar cells by low‐temperature transfer technology. Benefiting from the special low‐temperature adhesive and the Cu‐plated thin films, only one‐time bonding and extremely easy debonding are needed through the whole process and a negligible effect of residual stress can be obtained, which is critical to large‐size device fabrication. The optical model of light trapping and photon recycling based on the native textured back‐surface reflector of the flexible solar cell is constructed to design the antireflection coating. The flexible 4 in solar cells with a weight‐area density of only 169 g m−2 are successfully mass‐produced. The analysis of the individual subcells using optoelectronic reciprocity relation indicates that the GaAs middle subcell should be further optimized to improve the performance. The technique can be expected to achieve mass production of flexible high‐efficiency large‐size solar cells with low cost.

Rurality as context for innovative responses to social challenges – The role of rural social enterprises

Rural social enterprises are increasingly recognized as organisations that contribute to local development by providing goods and/or services to meet community needs and by fostering inclusive social and governance relations. The purpose of this paper is to explore how rural social enterprises engage in a plurality of socio-economic relations with different dimensions of their ‘place’ when contributing to the development of their localities. Based on three in-depth case studies of social enterprises operating in rural Ireland, our findings illustrate how rural social enterprises engage with locational, institutional, material and identity aspects of their ‘place’, which indicates their ‘placial embeddedness’. Moreover, our findings also demonstrate how these organisations engage in, and combine market, redistribution and reciprocity relations, which indicates their ‘substantive hybridity’. Based on the interrelated nature of these findings, we argue that it is through a process of placial substantive hybridity that rural social enterprises foster social innovation in order to contribute to an integrated development of their localities. They harness and (re)valorise (untapped) local resources while complementing these with other resources from extra-local sources and accommodate and/or respond to structural-exogenous forces based on the needs of their local population in line with neo-endogenous rural development.

An improved hybrid FE-SEA model using modal analysis for the mid-frequency vibro-acoustic problems

Based on the hybrid finite element (FE)-statistical energy analysis (SEA) method, an improved hybrid model with less time-consuming is proposed for the mid-frequency vibro-acoustic problems. Mode shapes are used to reduce the order of the deterministic acoustic component modeled by the finite element method in this paper. The governing equation of the residual response, which is derived to correct the modal truncation error, can be reduced by constructing a set of basis vectors. The model order reduction (MOR) equation of the acoustic component is formulated through a combination of the truncated mode shapes equation and the reduced residual response equation. The dimension of the overall equation of motion is efficiently decreased. The statistical structural component is modeled by SEA, and the responses of a mid-frequency vibro-acoustic system can be solved after introducing the diffuse field reciprocity relationship. Based on the efficient correction of the modal truncation error, the proposed hybrid MOR-SEA method promotes the reduction of order using mode shapes in mid-frequency vibro-acoustic systems. Compared with the traditional hybrid FE-SEA method, the present method has an evident advantage in computational efficiency, as shown in two numerical examples.

Array-Based Guided Wave Source Location Using Dispersion Compensation

Abstract An important advantage of guided waves is their ability to propagate large distances and yield more information about flaws than bulk waves. Unfortunately, the multi-modal, dispersive nature of guided waves makes them difficult to use for locating flaws. In this work, we present a method and experimental data for removing the deleterious effects of multi-mode dispersion allowing for source localization at frequencies comparable to those of bulk waves. Time domain signals are obtained using a novel 64-element phased array and processed to extract wave number and frequency spectra. By an application of Auld’s electro-mechanical reciprocity relation, mode contributions are extracted approximately using a variational method. Once mode contributions have been obtained, the dispersion for each mode is removed via back-propagation techniques. Excepting the presence of a small artifact at high frequency-thicknesses, experimental data successfully demonstrate the robustness and viability of this approach to guided wave source location.

Uniqueness of the Inverse Transmission Scattering with a Conductive Boundary Condition

This paper considers the inverse acoustic wave scattering by a bounded penetrable obstacle with a conductive boundary condition. We will show that the penetrable scatterer can be uniquely determined by its far-field pattern of the scattered field for all incident plane waves at a fixed wave number. In the first part of this paper, adequate preparations for the main uniqueness result are made. We establish the mixed reciprocity relation between the far-field pattern corresponding to point sources and the scattered field corresponding to plane waves. Then the well-posedness of a modified interior transmission problem is deeply investigated by the variational method. Finally, the a priori estimates of solutions to the general transmission problem with boundary data in Lp (∂Ω) (1 < p < 2) are proven by the boundary integral equation method. In the second part of this paper, we give a novel proof on the uniqueness of the inverse conductive scattering problem.

Uniqueness, continuous dependence and reciprocity theorems in thermoelastic relaxed micromorphic continuum

A mixed initial-boundary value problem is formulated for linear thermo-elastic relaxed micromorphic continuum with asymmetric micro-distortion tensor, micro-dislocation tensor and temperature field. First, Lagrange identity involving two admissible processes at different instants for the considered mixed initial-boundary value problem is established. Using this identity, four theorems are proved: (i) uniqueness of solution without recourse either to an energy conservation law or to any boundedness assumptions on the thermoelastic coefficients, (ii) continuous dependence of solution of the problem on loads, (iii) continuous dependence of solution of the problem on the initial data, and (iv) reciprocity relation. The use of positive definiteness conditions on the thermoelastic coefficients is also avoided.

Towards Balanced Reciprocity: The Relationship between Landowners and Landless Peasants in the Rural Community

Reciprocity relationships are a necessity in human life. This study aims to describe the various factors that determine the formation of balanced reciprocity in the relationship between land owners and farm laborers. The research's location was determined intentionally in the rural areas of Purbalingga Regency and Banyumas Regency, Central Java Province, Indonesia. This study used a qualitative method with a semi-grounded phenomenological research design. The results showed that a balanced reciprocity relationship was determined by a variety of principal and smoothing factors. The identification results showed that the main determinants include opportunity, benefit, mutual trust, closeness of social relations, motives for reciprocal exchange, openness in communication, willingness to give transactions to accept and return. The array of determinants of smoothing factors is routine contact and communication, empathy, tolerance, length of relationship, regularity of social interactions, network of cooperation, solidarity, transaction ability, mutual control and evaluation. The existence and strength of these two types of determining factors have an important function in the formation of balanced reciprocity among agricultural land owners and farm laborers. Willingness, self-awareness and opportunity are very important to develop to form balanced reciprocity.

Pressure and temperature driven fully-developed rarefied gas flow in a channel with uniform injection/suction through its permeable walls

The pressure and temperature driven fully-developed rarefied gas flow between two parallel permeable plates, with uniform gas injection and suction from the bottom and top plates respectively, is investigated, based on the linearized Shakhov (S) model and the linearized Boltzmann equation (BE). Both flow configurations are characterized by the gas rarefaction parameter and the injection/suction velocity magnitude. Computational results for the so-called kinetic coefficients, as well as for the macroscopic quantities are provided in a wide range of the two parameters. The Onsager-Casimir reciprocity relation between the mechanocaloric and thermal creep coefficients has been proven to hold for arbitrary values of the injection velocity and has been used to validate the accuracy of the obtained results. It is shown that, the kinetic coefficients and macroscopic quantities are significantly affected as the injection velocity is increased. In addition, the kinetic results properly recover the corresponding analytical solutions in the free molecular and slip regimes. The examined prototype rarefied injection/suction flows may be useful to the investigation of more complex and realistic flow configurations in channels of various cross-sections with permeable walls where the injection velocity is not constant in the whole flow domain.

Conductivity in the 2D Rayleigh Model for the Critical Concentration (Percolation Threshold)

The conductivity in the 2D Rayleigh model (isotropic matrix with a periodic distribution of circular inclusions) is considered for the critical concentration (percolation threshold). The effective conductivity of the model with the metal–ideal conductor phase transition is calculated using the binary approximation. The corresponding effective conductivity for an alternative model with a metal–insulator transition is determined from the Keller–Dykhne reciprocity relation.

Predictors of Job Performance and Psychological Contract Fulfillment as Mediator among Household Service Workers in Beijing, China

The objective of this paper is to investigate the relationship between these four variables namely: job satisfaction, authentic leadership, psychological contract fulfillment and Job performance with the theoretical models and literature. Although many studies have already been conducted on job satisfaction and job performance, authentic leadership and job performance, its relationship is still subject to many debates between those relationships. Hence in this paper use of psychological contract fulfillment as a mediator to explore the relationship of each variable With regards to psychological contract, showed that organization enable to fulfillment of the psychological contract with employee was far more important than other motivation, Social exchange theory has emphasized reciprocity relation, provides a theoretical foundation to understand employees perceive to their expectation of whether their psychological contracts have been reached Furthermore, it was also proven that job satisfaction; authentic leadership, psychological contract and job performance interact with each other and interdependently such that the process is circular. When job satisfaction and performance is linked with job performance, the outcome revealed that higher job satisfaction leads to higher job performance. When authentic leadership is linked with job performance, results showed that it is higher job performance. Importantly, psychological contract fulfillment is the key to achieve desirable outcomes which mean that organization should fulfillment of the promise that you have been committed with employees. On good organization, trust is a nonnegotiable. The psychological contract fulfillment will act with consistency, keep a good relationship, and maintain confidence and support everyone, the goal is to propel job performance of an employee.

Elevated Neurobehavioral Responses to Negative Social Interactions in Women With Bulimia Nervosa

BackgroundBulimia nervosa (BN) is a complex psychiatric illness that includes binge-purge behaviors and a belief that one’s value as a person depends on body shape and weight. Social pressure strongly influences the development and maintenance of BN, but how this manifests neurobiologically within an individual remains unknown. We used a computational psychiatry approach to evaluate neural mechanisms underlying social interactions in BN. MethodsBehavioral and functional magnetic resonance imaging data were collected from 24 women with BN and 26 healthy comparison women using an iterated social exchange game. Data were sorted round by round based on whether the mathematically computed social signals indicated an improving (positive reciprocity) or deteriorating (negative reciprocity) relationship for each participant. ResultsSocial interactions with negative reciprocity resulted in more negative behavioral responses and stronger neural activations in both cortical and subcortical regions in women with BN than healthy comparison women. No behavioral or neural differences were observed for interactions demonstrating positive reciprocity, suggesting a very specific form of psychopathology in BN: amplification of negative self-relevant social interactions. Cortical activations (e.g., temporoparietal junction and dorsolateral prefrontal cortex) did not covary with mood symptoms, while subcortical activations (e.g., amygdala and dorsal striatum) were associated with acute psychopathology. ConclusionsThese data provide a first step toward a mechanistic neuropsychological model of aberrant social processing in BN, demonstrating how a computational psychiatric approach can elucidate neural mechanisms for complex psychiatric illnesses. Future treatments for BN may include targeting neural regions that support these negative biases in social perceptions.

Food system integration of olive-oil-producing small farms in Southern Europe

This study aims to identify the various forms of integration of olive-oil-producing small farms (OSFs) into food systems in four Southern European regions, as well as to identify the most beneficial strategies of integration. Drawing on data from the SALSA Project, the study has found that besides self-provision, OSFs are engaged in multiple types of integration, including reciprocity relations as well as relations with informal and formal markets. Multiple strategies with synergistic effects co-exist at the farm/farm household level. However, specific territorial resources are partially mobilized by actors’ strategies; consequently, olive oil identities are valorized on the market to some extent, but less so through positive externalities. Therefore, the unrealized potential of localization of food systems in which OSFs operate is identified.

3-D Crosswell Electromagnetic Inversion Based on General Measures

The crosshole electromagnetic (EM) method is used in reservoir development monitoring and evaluation. It reflects the resistivity distribution between wells in the form of EM response changes and describes the spatial distribution of pore fluids in subsurface reservoirs based on the correlation between resistivity and pore fluids. This technique has been used to describe reservoirs, monitor steam and brine flooding to improve oil recovery, optimize the design of infilled wells, and verify the effectiveness of reservoir numerical simulations. However, due to the complexity of the electrical distribution of underground reservoirs and the limitations of the crosswell EM response range, there is still a lack of practical and effective crosswell EM imaging methods. This article presents a three-dimensional EM inversion scheme for interpreting crosswell data in the frequency domain with general measures. For the forward modeling, the equation for the secondary electric field was discretized using the staggered-grid finite difference scheme and was solved using the Krylov subspace iterative method. For the inversion problem, the general measure of the data misfit and regularization constraints were integrated using the Gauss–Newton minimization method to form an objective function. By selecting appropriate parameters and regularization constraints, the sharp boundaries and blocky features of the inverted target were recovered. The sensitivity was calculated using the reciprocity relationship, and the method was found to be beneficial to determining appropriate initial values of regularization coefficients. Two synthetic data sets and a field data inversion of a crosswell configuration demonstrate the feasibility of this scheme.

Subcells Analysis of Thin‐Film Four‐Junction Solar Cells Using Optoelectronic Reciprocity Relation

A thin‐film AlGaInP/AlGaAs/InGaAs/InGaAs inverted metamorphic multijunction solar cell with a bandgap of 1.96/1.53/1.16/0.83 eV is fabricated. The photoelectric conversion efficiency reaches 34.89% with an open‐circuit voltage of 3.54 V under AM1.5 G spectrum. The analysis of individual subcells is the key to evaluating the performance of multijunction solar cells. The current density versus voltage characteristics of four subcells are calculated using optoelectronic reciprocity relation between the external quantum efficiency and the different injection current densities electroluminescence. The analysis of the performance characteristics of four subcells concludes that the key to limiting the overall efficiency improvement is the deep‐level recombination of the AlGaInP top subcell and the bulk recombination of 0.83 eV InGaAs bottom subcell. Targeted optimization of the top subcell and the bottom subcell is expected to significantly improve efficiency.

Optoelectronic reciprocity in hot carrier solar cells with ideal energy selective contacts

AbstractHot carrier solar cells promise theoretical power conversion efficiencies far beyond the single junction limit. However, practical implementations of hot carrier solar cells have lagged far behind those theoretical predictions. Reciprocity relations for electroluminescence from conventional single junction solar cells have been extremely helpful in driving their efficiency ever closer to the theoretical limits. In this work, we discuss how the signatures of a functioning hot carrier device should manifest experimentally when driven in reverse, that is, in electroluminescent mode. Hot carrier properties lead to deviations of the dark I–V from the Shockley diode equation that is typical for conventional single junction solar cells. These deviations are directly linked to an increase in temperature of the carriers and therefore the temperature measured from electroluminescence spectra. We also elucidate how the behaviour of hot carrier solar cells in the dark depends on whether Auger processes play a significant role, revealing a stark contrast between the regime of negligible Auger recombination (carrier conservation model) and dominant Auger recombination (impact ionisation model) for hot carrier solar cells.