Physical Frame Research Articles

Modeling of drug release, erosion and diffusion fronts movement in high viscosity HPMC matrices containing a cellulolytic enzyme

A formerly developed mathematical model describing drug release from hydrophilic matrices (HMs) took into account resistance to drug release given by its dissolution and by the presence of a growing gel layer. Such a model was applied to previously reported release data obtained from HMs made of hydroxypropyl methylcellulose (HPMC), where acetaminophen was used as model drug and a cellulolytic product was added as “active” excipient to attain zero-order release kinetics. The Levich theory applied to acetaminophen intrinsic dissolution rate (IDR) data highlighted the suitability of such a drug for modeling purposes, given its good surface wettability. First assessment of the model ability to describe drug release from the abovementioned systems was carried out on partially coated matrices, representing a simplified physical frame, but results were then confirmed on uncoated systems. Experimental and model release data showed good agreement; therefore, the release-describing equation was combined with that of the global mass balance to obtain two new equations related to erosion and diffusion fronts time evolution. Changes over time in the dissolution and gel contributions to total resistance, calculated using model output parameters, highlighted that the enzyme, through its hydrolytic activity on HPMC, was responsible for a time-dependent reduction of the resistance component related to gel layer.

Harnessing coupled nanolasers near exceptional points for directional emission.

Tailoring the losses of optical systems within the frame of non-Hermitian physics has appeared very fruitful in the past few years. In particular, the description of exceptional points (EPs) with coupled resonators has become widespread. The on-chip realization of these functionalities is crucial for integrated nanophotonics but requires fine control techniques of the nanodevice properties. Here, we demonstrate pump-controlled directional emission of two coupled nanolasers that distantly interact via an integrated waveguide. This coupling scheme unusually enables both frequency and loss couplings between two cavities, which can be advantageously exploited to reach EPs by either detuning the cavities or controlling the gain of nanolasers. The system can be readily reconfigured from bidirectional to unidirectional emission by adjusting the pump power.

Nutritional Health and Its Impact on Students’ Academic Achievement

Introduction: Eating healthily, exercising regularly, getting enough sleep, managing stress, not taking drugs, leaning on friends and family, and cutting screen time are all proven predictors of long-term health and happiness. It is impossible to overestimate the significance of proper nutrition in a child's growth and development. Changes in diet during adolescence and young adulthood have far-reaching effects on later health and well-being.The problem and the aim of the study The two researchers looked at academic achievement and student malnutrition separately. The authors of this study hoped to shed light on how a bad diet affects academic performance, physical health, capacity to concentrate, and food choices. Research methods. In order to arrive at their findings, the researchers carried out several tests. The first step is to determine the height and weight of the children. A questionnaire will be given to the parents regarding the eating patterns of their family as well as the prevalence of Malnutrition. Finally, a test of pupil concentration will be administered. It should be noted that the sample was randomly selected from 105 children who were enrolled in grades three and four at Wadi Al-Seer, Amman's government-funded school for teachers. Results. The researchers used SPSS for statistical analysis, as well as descriptive statistics (rates and frequencies), to draw the following conclusions: Low academic achievement is strongly linked to Malnutrition. The degree of Malnutrition among students is strongly linked to their eating habits. A statistical comparison of well-nourished and malnourished students reveals that the former had weaker physical frames. A statistically significant difference exists between pupils who have problems focusing and those who eat less. Conclusion. If a parent is genuinely concerned about their child's health, they will provide them with healthy, well-balanced meals. We have a responsibility as parents and educators to help our children understand the value of a healthy diet and how it can help them reach their full potential throughout their lives. If they want to succeed, students must eat well. Schools must teach students and their families the importance of eating well. Received: 21 March 2024 / Accepted: 18 July 2024 / Published: 05 November 2024

A Study on the Effect of Structural Compliance Placing in Soft Contact/Collision Properties of Multirotor Micro Aerial Vehicles

Adding compliance (softness) has been introduced as an effective way to improve the physical collision resilience characteristics of multirotor micro aerial vehicles (MAVs). This article answers the question “Where is the best place to apply compliance in a multirotor MAV to make it more collision‐resilient?” by analyzing the output data of more than 1200 drone collision tests through two sets of accelerated and nonaccelerated collision experiments for four main configurations of micro‐quadcopters each possessing a unique softness layout of physical frame. It is shown that while applying compliance to the protective propeller guards (bumpers) of a micro‐quadcopter provides a more elastic collision, it does not improve its energy‐dissipation (impact damping) characteristics. On the other hand, enhancing the inner frame of the micro‐quadcopter with a softer structure results in higher rates of impact energy damping during the collisions and an increase in the impact time, which results in lower impact accelerations the MAV experiences during the crush. A mathematical model is developed representing the contact/collision interactions as nonlinear viscoelastic forces. Comparing the results of the simulations to the experiments suggests that this model can effectively mimic the impact behavior of contacting/colliding MAVs with different structural stiffness and damping.

A physical stochastic model of near-surface fluctuating wind fields

Modeling and simulation of atmospheric turbulence in coastal areas has emerged as a prominent area of research in recent years. This study presents a physical stochastic model to describe the horizontal coherence of fluctuating wind fields within the physical stochastic modeling frame. Based on the one-dimensional stochastic Fourier spectrum and isotropic turbulence theory, the horizontal coherence for fluctuating wind fields is expressed as a random function, with its probability information determined by the physical mechanism/background. The proposed physical stochastic model directly depicts the stochastic time series thereby enabling it to capture all probability information in detail comprehensively. The proposed model is numerically validated with the measured data obtained from an observation array constructed in Southeast China. This investigation holds significant potential for its application in wind-resistance design and reliability assessment of long-span structures.

Human Self: Structure of the Recognition-Behaviour Model-System Working with Language-Metabolism and Significance Induced by Symbolical Figuring the Meta-Model-System

Science organizes the recognizable targets of objects and phenomena in the testable form, and it functions to understand, define, quantify, visualize or simulate properties of the target in the syllogistic-hierarchy of framing, modeling, and explanation with sound inferences of language. Human Self maintaining the homeostasis is defined in the thinking-frame. The physical Self is the substantial model-system defined in the physical frame, and the mental Self is the recognition-behavioral model-system defined in the psychological frame. The recognition-behavioral model-system that was analyzed via the scientific procedure, was considered to perform language-metabolism with the thinking-codes of homology-/simplification, clustering, operation and modeling, which are mounted in the Modeling-layer of Neuronal Network of the brain, with economic and stubborn manner coming from the biological characteristics. Systems theory is the transdisciplinary study of systems complex-networked interrelated and interdependent components. Human Self is the meta-model-system complex-networked the functional single-model-systems. The mental Self that was re-defined corresponding to the physical/psychological model-system coming from Chinese philosophy and Chinese traditional medicine, developed to the neuro-psychological Self under the idea of Systems theory. Neuro-psycho-pharmacological effect of the anti-epileptic agents Carbamazepine, Lamotrigine and Valproate on Exceed Stimulation-amplify of patients suffering from Bipolar-disease, which was not clear until recently, was compatibly explained via the neuro-psychological Self. Finally, the emergent neuro-psycho-pharmacological explanation was considered to be induced by symbolically-figuring the neuro-psychological Self in the neuro-psychological frame.

Scalar cosmological perturbations from quantum gravitational entanglement

Abstract A major challenge at the interface of quantum gravity and cosmology is to explain the emergence of the large-scale structure of the Universe from Planck scale physics. In this letter, we extract the dynamics of scalar isotropic cosmological perturbations from full quantum gravity, as described by the causally complete Barrett-Crane group field theory model. From the perspective of the underlying quantum gravity theory, cosmological perturbations are represented as nearest-neighbor two-body entanglement of group field theory quanta. Their effective dynamics is obtained via mean-field methods and described relationally with respect to a causally coupled physical Lorentz frame. We quantitatively study these effective dynamical equations and show that at low energies they are perfectly consistent with those of General Relativity, while for trans-Planckian scales quantum effects become important. These results therefore not only provide crucial insights into the potentially purely quantum gravitational nature of cosmological perturbations, but also offer rich phenomenological implications for the physics of the early Universe.

Structural Optimization of 60T Electric Mining Vehicle Frame: Finite Element Simulation Model and Analysis

Based on the research under the ore loading condition of the electric mine vehicle, this paper measures the physical frame of the 60T electric mine vehicle by means of rangefinder, ruler and drawings, and uses the software CATIA to complete the three-dimensional model of the frame and carriage of the electric mine vehicle, combined with the characteristics of ANSYS workbench software. The structure of the model is simplified. By comprehensively applying relevant knowledge of automobile dynamics, the frame load under full load condition is calculated, and the electric mine vehicle frame is applied by using ANSYS workbench software to simulate and optimize the three conditions of stationary, high-speed driving and turning before the mine car, and the position where the stress concentration and deformation of the frame structure are greatest. By increasing the thickness of the support plate and increasing its stress area, the overall weight was increased by 90.35kg, accounting for 0.9% of the total weight, and the weight increase was very small. Mechanical analysis was carried out on the three working conditions of the optimized frame of the mine car, and the stress was reduced by 25%, 24.1% and 39.2% respectively, effectively eliminating the stress concentration. The actual use of the vehicle can extend the service life of the frame, while improving the economy and stability of the vehicle.

School trips to historical sites: students’ cognitive, affective and physical experiences from visits to Auschwitz

History can be experienced in many ways, including visits to historical sites. Indeed, it is becoming increasingly common for Swedish schools to organise trips for their students to historical sites; in this case, to concentration camps. This article analyses how cognitive, affective and physical experiences frame students’ interpretations of historical sites, and discusses how visits to historical sites might contribute to history education. The research questions we examine are as follows: What forms of experience did the students express, and how did these forms relate to each other? What implications might these expressed experiences pose for how teachers organise their teaching, including trips to Holocaust memorial sites? This article analyses seminars that comprised part of the examinable work in a course that involved a study trip to Auschwitz concentration camp. Empirical data were analysed using a model in which cognitive, affective and physical experiences were identified and described. The results demonstrate how cognitive, affective and physical responses interact with students’ experiences. Students described how the school trip contributed to their understanding of what is and is not possible to know, and to their will to influence society. Thus, the results indicate that physical encounters with historical sites can create new opportunities for students’ learning of history and the meaning making that comes from it.

Scalable Hardware-Efficient Architecture for Frame Synchronization in High-Data-Rate Satellite Receivers

The continuous technical advancement of scientific space missions has resulted in a surge in the amount of data that is transferred to ground stations within short satellite visibility windows, which has consequently led to higher throughput requirements for the hardware involved. To aid synchronization algorithms, the communication standards commonly used in such applications define a physical layer frame structure that is composed of a preamble, segments of modulation symbols, and segments of pilot symbols. Therefore, the detection of a frame start becomes an essential operation, whose accuracy is undermined by the large Doppler shift and quantization errors in hardware implementations. In this work, we present a design methodology for frame synchronization modules that are robust against large frequency offsets and rely on a parallel architecture to support high throughput requirements. Several algorithms are evaluated in terms of the trade-off between accuracy and resource utilization, and the best solution is exemplified through its application to the CCSDS 131.2-B-1 and CCSDS 131.21-O-1 standards. The implementation results are reported for a Xilinx KU115 FPGA, thereby showing the capability of supporting baud rates that are greater than 2 Gbaud, as well as a corresponding throughput of 15.80 Gbps. To the best of our knowledge, this paper is the first to propose a design methodology for parallel frame synchronization modules that has applicability to the CCSDS 131.2-B-1 and CCSDS 131.21-O-1 standards.

Bayesian-Optimized Riblet Surface Design for Turbulent Drag Reduction via Design-by-Morphing With Large Eddy Simulation

Abstract A computational approach is presented for optimizing new riblet surface designs in turbulent channel flow for drag reduction, utilizing design-by-morphing (DbM), large Eddy simulation (LES), and Bayesian optimization (BO). The design space is generated using DbM to include a variety of novel riblet surface designs, which are then evaluated using LES to determine their drag-reducing capabilities. The riblet surface geometry and configuration are optimized for maximum drag reduction using the mixed-variable Bayesian optimization (MixMOBO) algorithm. A total of 125 optimization epochs are carried out, resulting in the identification of three optimal riblet surface designs that are comparable to or better than the reference drag reduction rate of 8%. The Bayesian-optimized designs commonly suggest riblet sizes of around 15 wall units, relatively large spacing compared to conventional designs, and spiky tips with notches for the riblets. Our overall optimization process is conducted within a reasonable physical time frame with up to 12-core parallel computing and can be practical for fluid engineering optimization problems that require high-fidelity computational design before materialization.

Experimental study on asymmetric and bistable nonlinear energy sinks enabled by side tracks

To enhance the robustness of nonlinear energy sinks (NESs) against changes in input energy levels, various modifications to the restoring forces have been proposed. However, these improved devices may fail to achieve the expected effectiveness due to ineffective physical implementations. In this short communication, a novel realization method utilizing side tracks is employed to address this issue. Firstly, the development and mathematical descriptions of side-tracked NESs (ST-NESs) are presented. Subsequently, two energy-robust ST-NESs featuring asymmetric and bistable restoring forces are assembled and designed on a physical two-story frame structure subjected to impulsive excitation. Finally, the experimental responses of the two models are analyzed, and the comparison between the experiment and simulation is discussed. The results demonstrate that the proposed ST-NESs can be readily realized with limited vertical dimensions for practical applications. Besides, the device parameters that ensure good control capacities are not unique, providing flexibility in selecting different combinations of track shapes and springs. The experiment show that the two tested devices can reduce the structural response by 50% within five cycles and are minimally affected by changes in excitation levels. However, it is also found in the experiment that large friction among the interfaces of the assemblies in ST-NESs can cause immobility of the auxiliary mass, which should be avoided in future experiments and potential engineering applications.

Discrete symmetries of Dirac’s theory in the de Sitter manifold

The discrete symmetries of Dirac’s free field on the de Sitter manifold are studied, taking into account that this has two portions that can play the role of physical space-times, namely an expanding and a collapsing universe. The proper discrete isometries which preserve the portion have a physical meaning, in contrast to the improper ones, which change the portion being thus merely of mathematical interest. The discrete symmetries generated by the proper isometries and charge conjugation are studied in physical frames on the expanding portion, showing that all discrete transformations reversing the cosmic time are local, depending on a local boost matrix. The discrete group of Dirac’s theory in the de Sitter expanding universe is obtained, showing that this is of the order 16, having a multiplication table similar to that of Dirac’s theory in special relativity. Moreover, all the discrete de Sitter isometries, including the improper ones, are studied in conformal frames for obtaining a global image of the de Sitter isometries, despite the fact that these cannot be gathered in a larger discrete group with physical meaning.

Beyond the body/self-consciousness matrix: Scale of the physical frame of reference and self-transcendence experience.

Beyond the body/self-consciousness matrix: Scale of the physical frame of reference and self-transcendence experience.

An authentication scheme for FANET packet payload using data hiding

Flying ad hoc networks (FANETs) are gaining much traction in recent years due to their wide range of applications, resulting in the emergence of a number of studies on the facilitation of their widespread adoption. One of the key areas being investigated is the establishment of security strategies to combat the large amount and variety of security threats that they inevitably face when they are operating in the field. Since a majority of FANET’s operations involve the transmission of network packets containing both instructions and sensitive data, the protection of these packets is critical. This paper proposes an authentication scheme to protect the payload of the packets being transmitted within the FANET. Since FANETs are highly resource-constrained, we opted for a lightweight and energy-efficient approach. The proposed scheme essentially encodes the payload of a physical layer data frame into a compact bit stream, which is subsequently embedded into the cyclic prefix (CP) at the physical layer. The encoding process includes the XOR-operation and JBIG2 lossless compression. At the receiver’s end, the hidden authentication data is extracted and decoded for comparison against the payload of the received data frame. Two enhancements are introduced to further enhance robustness against masquerade attack. The proposed scheme is evaluated in terms of bit error rate (BER) under different signal-to-noise ratio (SNR) settings. In all considered SNR settings, the proposed authentication scheme achieves BERs of <0.7∗10−4 when 7-bit Hamming code is implemented. Experiment results also confirm that proposed scheme is able to localize the tampered data frames.

Quantum Modified Gravity at Low Energy in the Ricci Flow of Quantum Spacetime

Quantum treatment of physical reference frame leads to the Ricci flow of quantum spacetime, which is a quite rigid framework to quantum and renormalization effect of gravity. The theory has a low characteristic energy scale described by a unique constant: the critical density of the universe. At low energy long distance (cosmic or galactic) scale, the theory modifies Einstein's gravity which naturally gives rise to a cosmological constant as a counter term of the Ricci flow at leading order and an effective scale dependent Einstein-Hilbert action. In the weak and static gravity limit, the framework gives rise to a transition trend away from Newtonian gravity and similar to the MOdified Newtonian Dynamics (MOND) around the characteristic scale. When local curvature is large, Newtonian gravity is recovered. When local curvature is low enough to be comparable with the asymptotic background curvature corresponding to the characteristic energy scale, the transition trend produces the baryonic Tully-Fisher relation. For intermediate general curvature around the background curvature, the interpolating Lagrangian function yields a similar transition trend to the observed radial acceleration relation of galaxies. When the baryonic matter density is much lower than the critical density at the outskirt of a galaxy, there may be a universal "acceleration floor" corresponding to the acceleration expansion of the universe, which differs from MOND at its deep-MOND limit. The critical acceleration constant $a_0$ introduced in MOND is related to the low characteristic energy scale of the theory. The cosmological constant gives a universal leading order contribution to it and the flow effect gives the next order scale dependent contribution, which equivalently induces the "cold dark matter" to the theory. $a_0$ is consistent with galaxian data when the "dark matter" is about 5 times the baryonic matter.

Joint Physical Layer Frame Optimization and Carrier Synchronization for Satellite Communications

In this paper, we discuss general data-framing and optimization, parallel frequency-phase estimation, and powerful frequency estimator for satellite communications. Based on the standard pilot-symbol-assisted-modulation (S-PSAM) frame, we design a general PSAM (G-PSAM) frame, whose corresponding data-aided & non-data-aided Cramér-Rao bound (DA&NDA CRB) is derived with respect to carrier frequency offset, time delay and phase offset, followed by its approximate form. Also, we provide a simple solution to the G-PSAM frame optimization by means of the approximate DA&NDA CRB and the control-variate method. With an unbiased auto-correlation (AC) value, we then propose a frequency-phase decoupler and develop a parallel frequency-phase estimation (PFPE) mode in terms of the serial frequency-phase estimation (SFPE) mode, where a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">serial-to-parallel</i> estimation conversion can be implemented. Furthermore, we extend the AC frequency estimator in the PFPE mode as a powerful stepwise correlation-based one aiming at the target performance. Theoretical analysis and numerical results are provided to show the superiority of the optimized frames, the robustness of the PFPE mode, and the adaptability of the proposed frequency estimator with the optimized frames under different transmission systems.

Appraising the Water‐Energy‐Food Nexus From a Sustainable Development Perspective: A Maturing Paradigm?

AbstractThe water‐energy‐food (WEF) nexus is a prominent approach for addressing today's sustainable development challenges. In our critical appraisal of the WEF, covering different approaches, drivers, enablers, and applications, we emphasize the situation across the Global South (Africa, Asia, Latin America and the Caribbean). Here, WEF research covers at least 23 focal domains. We find that the nexus is still a maturing paradigm primarily rooted in a physical and natural sciences framing, which is itself embedded in a neoliberal securities narrative. While providing insights and tools to address the systemic interdependencies between resource sectors whose exploitation, degradation, and sub‐optimal management contribute to (un)sustainable development, there is still insufficient engagement with social, political, and economic dimensions. Progress related to climate, urbanization, and resource consumption is encouraging, but while governance and finance are central enablers of current and future nexus systems, gaps remain in relation to implementation and operationalization. Harnessing the nexus for sustainable development across the Global South means recognizing that it is more than a biophysical system, but also a multi‐scale complex of people, institutions, and infrastructure, affected by history and context. Addressing this complexity requires alternative and possibly challenging perspectives to counter dominant narratives, and manage problems associated with policy integration, trade‐offs, and winners and losers. We outline 10 emergent research areas that we think can contribute to this endeavor and enable the nexus to be a stronger policy force.

Reducing Minor Page Fault Overheads through Enhanced Page Walker

Application virtual memory footprints are growing rapidly in all systems from servers down to smartphones. To address this growing demand, system integrators are incorporating ever larger amounts of main memory, warranting rethinking of memory management. In current systems, applications produce page fault exceptions whenever they access virtual memory regions that are not backed by a physical page. As application memory footprints grow, they induce more and more minor page faults. Handling of each minor page fault can take a few thousands of CPU cycles and blocks the application till the OS kernel finds a free physical frame. These page faults can be detrimental to the performance when their frequency of occurrence is high and spread across application runtime. Specifically, lazy allocation-induced minor page faults are increasingly impacting application performance. Our evaluation of several workloads indicates an overhead due to minor page faults as high as 29% of execution time. In this article, we propose to mitigate this problem through a hardware, software co-design approach. Specifically, we first propose to parallelize portions of the kernel page allocation to run ahead of fault time in a separate thread. Then we propose the Minor Fault Offload Engine (MFOE), a per-core hardware accelerator for minor fault handling. MFOE is equipped with a pre-allocated page frame table that it uses to service a page fault. On a page fault, MFOE quickly picks a pre-allocated page frame from this table, makes an entry for it in the TLB, and updates the page table entry to satisfy the page fault. The pre-allocation frame tables are periodically refreshed by a background kernel thread, which also updates the data structures in the kernel to account for the handled page faults. We evaluate this system in the gem5 architectural simulator with a modified Linux kernel running on top of simulated hardware containing the MFOE accelerator. Our results show that MFOE improves the average critical path fault handling latency by 33× and tail critical path latency by 51×. Among the evaluated applications, we observed an improvement of runtime by an average of 6.6%.

The impact of interdisciplinarity and user involvement on the design and usability of an assistive upper limb exoskeleton - a case study on the EXOTIC.

This study describes an interdisciplinary approach to develop a 5 degrees of freedom assistive upper limb exoskeleton (ULE) for users with severe to complete functional tetraplegia. Four different application levels were identified for the ULE ranging from basic technical application to interaction with users, interaction with caregivers and interaction with the society, each level posing requirements for the design and functionality of the ULE. These requirements were addressed through an interdisciplinary collaboration involving users, clinicians and researchers within social sciences and humanities, mechanical engineering, control engineering media technology and biomedical engineering. The results showed that the developed ULE, the EXOTIC, had a high level of usability, safety and adoptability. Further, the results showed that several topics are important to explicitly address in relation to the facilitation of interdisciplinary collaboration including, defining a common language, a joint visualization of the end goal and a physical frame for the collaboration, such as a shared laboratory. The study underlined the importance of interdisciplinarity and we believe that future collaboration amongst interdisciplinary researchers and centres, also at an international level, can strongly facilitate the usefulness and adoption of assistive exoskeletons and similar technologies.