Differential Conditions Research Articles

Differential diagnosis of juvenile idiopathic arthritis and multiple epiphyseal dysplasia: Experience of multidisciplinary interaction

Introduction. Juvenile idiopathic arthritis (JIA) is a common multifactorial disease characterized by the presence of chronic inflammation in the joints, entheses and other structures of the musculoskeletal system in combination with a certain range of extraskeletal disorders. Vast variety of JIA clinical variants and the variability of the disease course make primary and differential diagnosis difficult, which often leads to a delayed start of treatment and an inadequate choice of medical therapy or, conversely, an excess of medication. In the range of differential diagnostic conditions that have similar symptoms and are manifested by severe arthralgia, gait disturbance, joint stiffness, as well as the presence of effusion and gradual progression of bone destruction mainly in the epiphyseal plate, one should remember about hereditary skeletal dysplasias, primarily from a genetically heterogeneous group of multiple epiphyseal dysplasias (MED). The aim of the study – description of the clinical and genetic characteristics of three patients with various genetic variants of MED and defining approaches for their differential diagnosis with JIA. Materials and methods. There were three patients from three unrelated families aged from 7 to 13 years old under our supervision. To clarify the diagnosis, a genealogical analysis, a clinical examination of patients and first-degree relatives, as well as an assessment of X-ray images of long tubular bones were carried out. Molecular genetic confirmation of the MED diagnosis types 1 and 2 was based on the results of custom panel sequencing consisting of 166 genes responsible for the development of hereditary skeletal pathology. To clarify the molecular genetic diagnosis of MED type 4, an analysis of the SLC26A2 gene was performed using automated Sanger sequencing. Results. Anamnestic, clinical, radiological, and molecular genetic characteristics of three unrelated patients with different genetic types of MED caused by variants in the COMP, SLC26A2, and COL9A2 genes were analyzed. The first symptoms of the disease in observed patients with three different genetic variants of MED occurred at the age of 2–3 years old and were characterized by gait disturbance and climbing stairs difficulties. Gradually, these symptoms were accompanied by pain in large joints. According to the ultrasound examination of the joints, signs of synovitis were noted, as a result they were diagnosed with JIA (polyarticular variant, seronegative for rheumatoid and antinuclear factor) and immunosuppressive therapy were prescribed without significant effect. The atypical course of the JIA was the reason for additional examination of patients by an orthopedist and geneticist. Careful analysis of the large joints radiographs made it possible to suspect one of the variants of MED in our patients based on the detection of distinctive signs, which were characterized by abnormal ossification (diminished size and flattening) of the epiphyses and abnormal shape and structure of the femoral head epiphysis. Molecular genetic analysis was performed to confirm the diagnosis. As a result, a pathogenic variant of the nucleotide sequence in the COMP gene was detected in one of the patients, two pathogenic variants in the SLC26A2 gene in another patient, and one pathogenic variant in the COL9A2 gene in the third patient, which made it possible to confirm the final diagnosis of MED type 1 with an autosomal dominant type of inheritance, MED type 4 with an autosomal recessive type of inheritance and MED type 2 with an autosomal dominant type of inheritance, respectively. Based on the results of our own research and analysis of the literature data, key directions for the differential diagnosis of MED and JIA were formulated. It is shown that the analysis of the X-ray images of patients is essential in differential diagnosis. Conclusion. Despite the significant overlap of the clinical symptoms between JIA and MED, the key to the early diagnosis of MED is a comprehensive examination, which included genealogical analysis, features of clinical manifestations and disease course in combination with distinctive radiological signs including delayed ossification of the epiphyses of tubular bones typical for MED. However, the question remains about the probability of a combined nature of osteoarticular disorders, i. e., the possible development of JIA in patients with hereditary skeletal dysplasias which requires in-depth study in the future.

Heat Production Capacity Simulation and Parameter Sensitivity Analysis in the Process of Thermal Reservoir Development

The development of a geothermal system involves changes in the temperature field (T), seepage field (H), stress field (M), and chemical field (C) and the influence among them and injecting the heat extraction working fluid into the injection well that flows (migrating) through natural fractures and exchanges heat with the geothermal high-temperature rock. At the same time, the injection of low-temperature working fluid will induce thermal stress, resulting in changes in the reservoir temperature field and stress field. To study the influence factors and influence degree of heat production performance and mining life under multi-field coupling in the process of thermal reservoir development, based on THMC multi-field coupling numerical simulation software, this paper deeply studies the control differential equations and boundary coupling conditions of rock mass (fracture) deformation, seepage, heat exchange, the chemical reaction, and other processes based on the numerical solution method of the discrete fracture network model, simulating heat production capacity during the deep geothermal resource extraction process. The reservoir geological model analysis and generalization, parameter setting, boundary conditions, initial condition settings, mesh generation, and other steps were carried out in turn. Two different heat extraction working fluids, water, and CO2 were selected for numerical simulation in the mining process. The changes in the thermal reservoir temperature, net heat extraction rate, and SiO2 concentration during the thirty years of systematic mining were compared. The results show that CO2 has a better heat extraction effect. Finally, the reservoir thermal conductivity, heat capacity, well spacing, injection temperature, fracture spacing, fracture permeability, fracture number, fracture length, and other parameters were set, respectively. The parameter variation range was set, and the parameter sensitivity analysis was carried out. The numerical simulation results show that the engineering production conditions (injection temperature, well spacing) have little effect on the thermal efficiency and mining life, and the properties of fractures (fracture permeability, fracture number, fracture length) have a great influence.

Fuzzy Caputo [formula omitted]-fractional linear equations on the time scale [formula omitted

In this paper, we explore various concepts in q-fractional calculus and extend them to the fuzzy domain. Specifically, we define fuzzy q-exponential and fuzzy q-Mittag-Leffler functions using r-cuts. Additionally, we evaluate the fuzzy Caputo q-derivatives of the fuzzy q-exponential functions and introduce the concept of fuzzy q-Laplace transform. Furthermore, we provide a formula for the fuzzy q-Laplace transform of the fuzzy Caputo q-fractional derivative.We also tackle the problem of solving fuzzy Caputo q-fractional linear differential equations under the generalized Hukuhara differentiability conditions, with a focus on specific forcing functions. The key technique employed for solving these equations is the fuzzy q-Laplace transform. To illustrate the practicality of our theoretical results, we present several numerical examples.This paper contributes to the development of q-fractional calculus in the context of fuzzy mathematics and provides valuable insights into solving fuzzy differential equations using the proposed techniques.

Saturation function-based continuous control on fixed-time synchronization of competitive neural networks

Currently, through proposing discontinuous control strategies with the signum function and discussing separately short-term memory (STM) and long-term memory (LTM) of competitive artificial neural networks (ANNs), the fixed-time (FXT) synchronization of competitive ANNs has been explored. Note that the method of separate analysis usually leads to complicated theoretical derivation and synchronization conditions, and the signum function inevitably causes the chattering to reduce the performance of the control schemes. To try to solve these challenging problems, the FXT synchronization issue is concerned in this paper for competitive ANNs by establishing a theorem of FXT stability with switching type and developing continuous control schemes based on a kind of saturation functions. Firstly, different from the traditional method of studying separately STM and LTM of competitive ANNs, the models of STM and LTM are compressed into a high-dimensional system so as to reduce the complexity of theoretical analysis. Additionally, as an important theoretical preliminary, a FXT stability theorem with switching differential conditions is established and some high-precision estimates for the convergence time are explicitly presented by means of several special functions. To achieve FXT synchronization of the addressed competitive ANNs, a type of continuous pure power-law control scheme is developed via introducing the saturation function instead of the signum function, and some synchronization criteria are further derived by the established FXT stability theorem. These theoretical results are further illustrated lastly via a numerical example and are applied to image encryption.

Математичні моделі температурного поля у елементах електронних пристроїв із чужорідним включенням

Linear and non-linear mathematical models for the determination of the temperature field, and subsequently for the analysis of temperature regimes in isotropic media with semi-transparent foreign inclusions that are also subject to external heat load, have been developed. To solve the nonlinear boundary-value problem, a linearizing function was introduced, using which the original nonlinear heat conduction equation and nonlinear boundary conditions were linearized, and as a result, a partially linearized second-order differential equation with partial derivatives and discontinuous and singular coefficients relative to the linearizing function and partially linearized boundary conditions was obtained. For the final linearization of the partially linearized differential equation and boundary conditions, the approximation of the temperature according to one of the spatial coordinates on the boundary surfaces of the inclusion was performed by piecewise constant functions. To solve the obtained linear boundary value problem, the Hankel integral transformation method was used, as a result of which an analytical solution was obtained, which determines the introduced linearizing function. For the numerical analysis of temperature behavior and heat exchange processes caused by external heat load, software tools have been developed, which are used to create a geometric image of temperature distribution depending on spatial coordinates. The obtained results indicate the correspondence of the developed mathematical models of the analysis of heat exchange processes in heterogeneous media with external heating to a real physical process. The obtained results indicate the correspondence of the developed mathematical models of the analysis of heat exchange processes in heterogeneous media with external heating to a real physical process. The developed models make it possible to analyze environments with foreign elements under external thermal loads regarding their thermal resistance. As a result, it becomes possible to increase it and protect it from overheating, which can cause the destruction of not only individual elements, but also the entire structure.

Physiological and psychological responses to transitions between urban built and natural environments using the cave automated virtual environment

Observational and experimental studies have illustrated that exposure to greenness is beneficial to long-term health and well-being. In the urban context, however, more evidence is needed for a better understanding of the short-term health impacts of nearby nature. To address this limitation, we investigated the dynamic influence of transitions between built and natural environments on urban residents using Cave Automated Virtual Environment (CAVE) immersive virtual reality technology. In this experiment, we filmed two pairs of 360° 8K videos of geographically adjacent built and natural environments in Boston, MA to mimic real-life environmental exposure of urban residents, and created virtual immersive stimuli with an 8K-resolution curved panoramic screen accompanied with a 7.2 Dolby Surround 360° audio system. We recruited 171 participants in a randomized crossover experiment to evaluate physiological and psychological responses to transitions between urban built and natural environments. Our psychological results indicate significant reductions in negative mood dimensions, total mood disturbance, and transient anxiety, during the transition from built to natural environments; and increases during the transition from natural to built environments. In addition, we observed participants showed more emotional responses to nature through physiological measures. Lastly, we found that contextual factors that were rarely tested in previous studies, including differential physical health conditions, underlying stress levels, formative experience with nature, and growth environments, might influence the extent of stress recovery. This study provided empirical evidence from the health perspective for promoting nearby nature in urban built environments.

Effects of emotional labor on the turnover intention of kindergarten teachers: A moderated mediation model

We explored the differential impact mechanism and boundary conditions of emotional labor and its subdimensions on the turnover intention of kindergarten teachers. Our research was based on the job demands–resources model and the concept of symbolic interactionism. The results of a survey conducted with 3,679 in-service kindergarten teachers showed that use of emotional labor strategies had a significant positive predictive effect on the turnover intention of kindergarten teachers. Further, professional identity played a partial mediating role in the link between teachers' emotional labor (surface acting) and their turnover intention. Finally, we found that as the length of teaching service increased, surface acting had a greater influence on teachers' professional identity. Thus, kindergarten teachers' turnover intention can be effectively reduced through surface acting.

Revaluating coal permeability-gas pressure relation under various gas pressure differential conditions

Identifying changes in coal permeability with gas pressure and accurately codifying mean effective stresses in laboratory samples are crucial in predicting gas-flow behavior in coal reservoirs. Traditionally, coal permeability to gas is assessed using the steady-state method, where the equivalent gas pressure in the coal is indexed to the average of upstream and downstream pressures of the coal, while ignoring the nonlinear gas pressure gradient along the gas flow path. For the flow of a compressible gas, the traditional method consistently underestimates the length/volume-averaged pressure and overestimates mean effective stress. The higher the pressure differential within the sample, the greater the error between the true mean pressure for a compressible fluid and that assumed as the average between upstream and downstream pressures under typical reservoir conditions. A correction coefficient for the compressible fluid pressure asymptotes to approximately 1.3%, representing that the error in mean pressure and effective stress can be on the order of approximately 30%, particularly for highly pressure-sensitive permeabilities and compressibilities, further amplifying errors in evaluated reservoir properties. We utilized this volume-averaged pressure and effective stress to correct permeability and compressibility data reported in the literature. Both the corrected initial permeability and the corrected pore compressibility were found to be smaller than the uncorrected values, due to the underestimation of the true mean fluid pressure, resulting in an overestimation of reservoir permeability if not corrected. The correction coefficient for the initial permeability ranges from 0.6 to 0.1 (reservoir values are only approximately 40% to 90% of laboratory values), while the correction coefficient for pore compressibility remains at approximately 0.75 (reservoir values are only approximately 25% of laboratory value). Errors between the uncorrected and corrected parameters are quantified under various factors, such as confining pressure, gas sorption, and temperature. By analyzing the evolutions of the initial permeability and pore compressibility, the coupling mechanisms of mechanical compression, adsorption swelling, and thermal expansion on the pore structure of the coal can be interpreted. These findings can provide insights that are useful for assessing the sensitivity of coal permeability to gas pressure as truly representative of reservoir conditions.

A comparison of FEM results from the use of different governing equations in a galvanic cell part I: In the presence of a supporting electrolyte

The use of reduced-order models for simulating potential, current density, and species distributions in an electrolyte are attractive due to the high computational costs required to solve the intricate set of highly nonlinear partial differential equations and boundary conditions characteristic of electrochemistry problems. The loss in accuracy of the reduced-order models is assessed in this work by the comparison of the results obtained by these reduced-order models to those from the most general model (i.e., using the Nernst-Planck-Poisson as the governing equation). The models were performed using the governing equations available on COMSOL Multiphysics®. For electrolyte concentrations typical of most environments of interest in corrosion and electrochemistry, the reduced-order models saved substantial computational time without significant loss in accuracy.

"How can they treat it if they can't identify it?": Mental health professionals' knowledge and perspectives of moral injury.

Moral injury (MI) is a stressor-related phenomenon that may entail long-term ramifications. However, no study to date has examined mental health professionals' (MHPs') knowledge and treatment perspectives regarding patients with MI. This study aims to shed light on MHPs' perspectives in an experimental design using a manipulation concerning a hypothetical patient. The sample included 846 MHPs who were presented with one of four vignettes of a virtual patient with differential clinical conditions. Participants were then posed several questions regarding the patient's clinical condition, their willingness to treat, and their knowledge regarding MI. Most participants reported no knowledge regarding MI. MHPs receiving MI-related scenarios were less willing to treat and more willing to refer the patient out than MHPs receiving non-MI scenarios. Professional seniority and training concerning MI contributed to greater familiarity with MI. The findings highlight that MHPs have minimal knowledge of MI, which may relate to their reluctance to treat patients with the psychological manifestations of MI. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Finite-Time Stabilization of Fuzzy Spatiotemporal Competitive Neural Networks With Hybrid Time-Varying Delays

This paper focuses on the finite-time stabilization problem for fuzzy spatiotemporal competitive neural networks (FSCNNs) with discrete and distributed delays. First, the differentiable conditions for discrete and finite distributed delays in FSCNNs are removed, and the constraints of the kernel function in infinite distributed delays are weakened. Then, a novel partial differential inequality is proposed to handle the spatial diffusions, which relaxes the restriction for symmetric around the origin of the bounded spatial domain. To stabilize FSCNNs within a finite time, a novel control strategy without delay-dependent terms is established. Moreover, different from the existing works, a more succinct Lyapunov functional is constructed, which does not need to include multiple integral type functional terms to eliminate the influence of the hybrid delays. By virtue of the comparison method and inequality techniques, several sufficient criteria are deduced to guarantee the finite-time stabilization of FSCNNs. Finally, simulations are presented to illustrate the feasibility and effectiveness of the theoretical results.

Numerical Solution of Natural Convection Nanofluid Flow over aNon-Isothermal Vertical Plate

The natural convection nanofluidflow over a non-isothermal vertical plate is studied numerically. The effects of Brownian motion and thermophoresis parameters are incorporated into models used for nanofluids. The non-linear partial differential equations and boundary conditions are transformed into a set of nonlinear ordinally differential equations using the similarity transformations. The resulting system of equations are solved numerically by using shooting techniques. This solution depends on the Prandtl number (Pr), Buoyancy ratio (Nr), Brownian-motion (Nb), thermophoresis parameter (Nt), Lewis number (Le), and power-law exponent (λ). For different values of λ, Le and Pr, the influence of reduced Nusselt number with Nr, Nb and Nt is represented by correlation formulas and compared with previously published results and found to be in better agreement.

A density functional theory study on how γ-Al2O3 – Boehmite transformation affects carbon evolution during aqueous-phase reaction

Gamma-alumina (γ-Al2O3), one of the most common materials, is commercially used in many catalytic applications, including the active catalyst and support. However, the problem of fast deactivation makes the utilization of the γ-Al2O3 challenging. This work elucidates the mechanism of coke formation consisting of coke deposition and evolution on γ-Al2O3(110) surfaces in differential conditions, including; clean and hydroxylation γ-Al2O3(110) in terms of partial and fully hydroxylation of OH/γ-Al2O3(110) and AlOOH(010), respectively. We demonstrated that the γ-Al2O3(110) surface is proper for atomic coke deposition and dimerization in the initial state, where the presence of OH species promotes the coke evolution to higher coke, Cn (where n ≥ 3). Also, the higher coke formation thermodynamically preferred the cyclic form to the aliphatic one. The electron transfer from substrates to adsorbed coke illustrates the role of the electron donor of catalyst surfaces corresponding to the electron acceptor of adsorbed cokes.

Discrepant Approaches to Modeling Stellar Tides and the Blurring of Pseudosynchronization

We examine the reasons for discrepancies between two alternative approaches to modeling small-amplitude tides in binary systems. The direct solution (DS) approach solves the governing differential equations and boundary conditions directly, while the modal decomposition (MD) approach relies on a normal-mode expansion. Applied to a model for the primary star in the heartbeat system KOI-54, the two approaches predict quite different behavior of the secular tidal torque. The MD approach exhibits the pseudosynchronization phenomenon, where the torque due to the equilibrium tide changes sign at a single, well-defined, and theoretically predicted stellar rotation rate. The DS approach instead shows “blurred” pseudosynchronization, where positive and negative torques intermingle over a range of rotation rates. We trace a major source of these differences to an incorrect damping coefficient in the profile functions describing the frequency dependence of the MD expansion coefficients. With this error corrected, some differences between the approaches remain; however, both are in agreement that pseudosynchronization is blurred in the KOI-54 system. Our findings generalize to any type of star for which the tidal damping depends explicitly or implicitly on the forcing frequency.

A Physics-informed Neural Network for Pulsed Thermography- Based Defect Detection

The non-destructive testing technique of pulsed thermography has been widely used in materials to detect defects due to its low cost, large detection area, and rapid implementation. After conducting experiments, data processing is often necessary to reduce the influences of noise and non-uniform backgrounds and highlight defect information. However, during the analysis, physical information is usually ignored. In addition to thermographic data analysis, numerical simulations are also popular for analytical studies based on physical information, but they don’t fully utilize the experimental data. To address this, a new method was proposed using a physics-informed neural network (PINN) for thermographic data processing. PINN combines the prediction capabilities of deep neural networks with physical laws presented as partial differential equations and boundary conditions, allowing for both experimental data and physics information to be utilized in modelling. In pulsed thermography, the heat transfer is governed by Fourier's law of heat conduction in a three-dimensional system. However, there is a lack of temperature measurements in the depth direction. The proposed method solves this problem by using collocation points generated from Latin hypercube sampling. The PINN model provides a good estimation of the backgrounds in the thermograms, and the features of surface/subsurface defects are highlighted by subtracting the estimated backgrounds from the original thermograms. In the case study, the performance of the proposed method was found to be effective.

Multiple Slip Effects of Boundary Layer Maxwell-Nanofluid Flow Past a Stretching Sheet: Magnetic Field and Cross Diffusion Effects

The authors are interested in understanding how a magnetic field and cross diffusion influence non-Newtonian Maxwell-Nanofluid boundary layer flow towards a nonlinearly stretched sheet when there are also Thermophoresis and Brownian motion reaction present in the system. Specifically, the purpose of this research is to learn more about the Maxwell and nanofluid properties of a stretched sheet in a normal magnetic field, as well as the reactions of three distinct slip situations (velocity, thermal, and solutal). Partially differential equations with nonlinear coefficients are used to obtain the governing conditions. These conditions are changed into profitable non-direct common differential conditions by utilizing the suitable change factors and change coefficients. To explore the mathematical results of the diminished arrangement of non-direct customary differential conditions, it was created and utilized the Keller box technique, which was produced for mathematical results. The reproduction considers the nanofluid speed, temperature, focus, skin grating coefficients, heat move rate, and mass exchange rate, among different factors. The validity of this strategy is shown through a correlation of the current outcomes with past discoveries in the writing. From this exploration work, the speed profiles are expanding with expanding upsides of Maxwell liquid boundary and diminishes with expanding upsides of Magnetic field and speed slip boundaries. With expanding impacts of Thermophoresis and Brownian movement, the temperature profiles are increment. As the upsides of Dufour number builds, the temperature profiles are additionally increments. A development of the Thermophoresis boundary prompts expanded nano particle volume focus circulation and the opposite impact is seen in the event of Brownian movement impact. The focus profiles are expanding with rising upsides of Soret number boundary.

Orthostatic proteinuria due to inferior vena cava interruption without nutcracker phenomenon in an old obese female: a case report and literature review

BackgroundNutcracker syndrome (NCS) caused by left renal vein (LRV) entrapment, is one of the most common causes of orthostatic proteinuria. In stereotype, orthostatic proteinuria is often accompanied by left renal vein obstruction and is found in young and underweight individuals. Here, we report a rare case with orthostatic proteinuria in an old obese female caused by a rare type of congenital inferior vena cava (IVC) interruption.Case presentationA 65-year-old obese woman, who suffered from fluctuated proteinuria, had been misdiagnosed as chronic glomerulitis for 30 years. Instead of having any sign of NCS, she had a unique type of IVC interruption. Most venous blood from infrarenal IVC and right kidney drained into her LRV, and then through the expanded communicating vessel, drained into the left ascending lumbar vein which extended as hemiazygos vein. To the best of our knowledge, this is one of the first cases reported of orthostatic proteinuria attributed to the subsequent hemodynamic irregularity caused by IVC interruption without nutcracker phenomenon.ConclusionAdult-onset orthostatic proteinuria is relatively rare, hard to be recognized and could be misdiagnosed as chronic glomerulonephritis. The case provided a novel differential diagnostic condition for those who suffered from fluctuated proteinuria of unknown causes.

Utilising physics-informed neural networks for optimisation of diffusion coefficients in pseudo-binary diffusion couples

ABSTRACT We propose a numerical inverse method based on physics-informed neural networks (PINN) for calculating composition-dependent diffusion coefficients in pseudo-binary (PB) diffusion couples in multicomponent alloys. Traditional methods rely solely on experimental diffusion profiles as design targets, which can lead to unreliable estimates. In contrast, PINN uses a combination of available data and physics-based constraints to obtain optimised design parameters and exact solutions for constrained governing differential equations. The constraints in PINN include governing partial differential equations, initial and boundary conditions, and any other equality/inequality relations obeyed by physical parameters. Our study shows the necessity of experimentally estimated intrinsic diffusion coefficients for the prediction of reliable composition-dependent mobility data. In the absence of such data, different combinations of unknown intrinsic diffusion coefficients can also produce reasonable approximations of diffusion profiles and interdiffusion coefficients while wrongly predicting more fundamental quantities (i.e. intrinsic diffusivities). Our method utilises PINN to simultaneously obtain optimised design parameters (diffusion coefficients) and exact solutions for governing diffusion equations. The implementation of PINN uses experimentally estimated diffusion coefficients obtained by the PB diffusion couple method, in addition to diffusion profiles, as design targets. The method is extended to non-ideal PB diffusion profiles, such as conventional diffusion couples in which all the components develop diffusion profiles, by incorporating additional constraints such as zero composition gradient of certain component(s) and experimentally estimated interdiffusion coefficients at extrema in the composition profiles. PINN is found to be a promising approach for obtaining reliable estimates of diffusion coefficients in multicomponent alloys.

A Cross-Layer Media Access Control Protocol for WBANs

Wireless body area network (WBAN) is an emerging comprehensive technology that can deeply integrate with e-health and smart sports. As a wearable network, improving the quality of network service and user experience is crucial. Due to the miniaturized design of sensors, their available energy from batteries is limited, making the extension of their lifetime a key research challenge. Existing studies have proposed methods to improve energy efficiency, but there are still limitations in addressing dynamic adaptive aspects of differential energy distribution and channel conditions. In order to further extend the lifetime of sensor nodes and networks while ensuring quality of service, and to provide a reliable transmission mechanism for heterogeneous application data, this paper presents a cross-layer optimized MAC protocol mechanism. The protocol takes into account the transmission requirements of different types of data and redesigns the superframe. To improve the lifetime of nodes, we propose an energy-adaptive adjustment mechanism considering the channel conditions. At the same time, a cooperative transmission mechanism is proposed to further enhance network lifetime. In experiments conducted on two typical networks, compared to IEEE 802.15.6, the power adjustment scheme improves the network lifetime by 2.8 to 3.7 times, and the cooperative mechanism between nodes further increases the network lifetime by 17% to 44%. Our proposed scheme effectively extends the network lifetime while ensuring quality of service, avoiding frequent battery resets for users, and effectively improving the user experience quality.

Thermal Stress Formation in a Functionally Graded Al2O3-Adhesive Single Lap Joint Subjected to a Uniform Temperature Field

This study investigates the strain and stress states in an aluminum single lap joint bonded with a functionally graded Al2O3 micro particle reinforced adhesive layer subjected to a uniform temperature field. Navier equations of elasticity theory were designated by considering the spatial derivatives of Lamé constants and the coefficient of thermal expansion for local material composition. The set of partial differential equations and mechanical boundary conditions for a two-dimensional model was reduced to a set of linear equations by means of the central finite difference approximation at each grid point of a discretized joint. The through-thickness Al2O3-adhesive composition was tailored by the functional grading concept, and the mechanical and thermal properties of local adhesive composition were predicted by Mori–Tanaka’s homogenization approach. The adherend–adhesive interfaces exhibited sharp discontinuous thermal stresses, whereas the discontinuous nature of thermal strains along bi-material interfaces can be moderated by the gradient power index, which controls the through-thickness variation of particle amount in the local adhesive composition. The free edges of the adhesive layer were also critical due to the occurrence of high normal and shear strains and stresses. The gradient power index can influence the distribution and levels of strain and stress components only for a sufficiently high volume fraction of particles. The grading direction of particles in the adhesive layer was not influential because the temperature field is uniform; namely, it can only upturn the low and high strain and stress regions so that the neat adhesive–adherend interface and the particle-rich adhesive–adherend interface can be relocated.