Fundamental Explanation Research Articles

On the Anisotropic Milling Machinability of DD407 Single Crystal Nickel-Based Superalloy.

The DD407 single crystal Ni-based superalloy with a face-centered cubic structure exhibits strong anisotropic characteristics. In order to reveal the material chip formation mechanism and the impact effect of crystal orientations on the materials’ milling machinability, a combination of experimental observations and theoretical analysis were applied in this study. Considering the resolved shear stress and slip system theories, a fundamental theoretical explanation of the milling force and surface quality along different crystal directions on the (001) crystal plane of the DD407 single crystal Ni-based superalloy was proposed based on a previously constructed anisotropic milling model. Our work in this research verifies that [110] crystal direction on the (001) crystal plane of the DD407 single crystal Ni-based superalloy is the most optimal feeding direction during milling, taking into account surface roughness and morphology, slot bottom plastic deformation, work hardening, and chip edge burr feature.

Influence of surface properties on the dynamics of fluid flow

In this paper, we study how the fluid flow near the surface of a monocrystalline body is affected by the surface properties due to atom-surface scattering. We propose a toy model for this system by parameterizing the surface with a periodic function of the tangential position. This allows us to derive the velocity probability density function in the Knudsen layer and determine statistical averages of fluid velocity and stress tensor components in the region of interest. The results of this analysis provide a potentially more fundamental and accurate explanation for empirically observed phenomena such as the no-slip boundary condition, boundary layer formation, and the onset of hydrodynamic instability.

A ‘virtual sensing’ framework for µECM/hybrid laser- µECM for monitoring interelectrode gap conditions

Micro-ECM (µECM) has capability to process wide class of conductive materials ranging from metals, cermets to bulk metallic glasses and shape memory alloys. The process efficiency and speed is further enhanced by hybridization of micro-ECM process with laser which can act as a localized heat source or a cutting energy source depending on the fluence on the workpiece surface. The hybridization of micro-ECM with laser facilitates machining of materials/alloys with conductivity variations and promotes their uniform dissolution. The process mechanism involves several multiphysics phenomena occurring in the interelectrode gap (IEG) which is of the order of 20-50 µm. The technological limitations of putting sensors in this small IEG limits the monitoring of physical quantities (such as temperature, hydrogen and oxygen gas volume fraction, electrolyte conductivity, current density on workpiece surface) during the process. However, these physical quantities can be effectively estimated by multiphysics simulations.At first, the experimental experience with different sensors (temperature sensor, current sensor, high speed imaging and particle image velocimetry (PIV)) is presented for µECM/hybrid laser-µECM process and their limitations are discussed. Subsequently, this work proposes a ‘virtual sensing’ approach enabled by multiphysics simulations. A detailed multiphysics model is developed in Comsol® software which models several phenomena occurring in µECM/hybrid laser-µECM process such as temperature-dependent electrolyte properties, hydrogen and oxygen gas generation, heat generation due to joule heating and laser heating, laminar fluid flow and electric currents. The properties are evaluated at 5 different (virtual sensor) locations inside the IEG, more specifically on the workpiece surface, tool surface, in the center of IEG, just at the exit of IEG and at a specified location. These virtual sensors are implemented in the Comsol® software by employing a dynamic point probe which probes the model-solution at a defined point in a moving geometry. The evolution of the aforementioned parameters in the IEG is monitored and supported by fundamental explanations as well as observational experiments. This research is a first step towards facilitating predictive sensing of ECM and allied multiphysics processes thereby supporting process design and minimizing experimental efforts by virtual process monitoring.

The Paradox of Credit Scoring Model Deterioration

Scoring models are widely renowned and used in financial organizations in a variety of fields, but most importantly – to predict and control credit risk. This article addresses practical problems of scorecards usage after its implementation. With time its predictive power tends to deteriorate, but not always it is applicable to completely rebuild the model fast enough due to lack of time/human/financial resources. Then cut-off, which was set when the scorecard was initially implemented, should be corrected to achieve optimal (i.e. cash-flow maximizing) performance. The literature on ways to maintain the existing model over time and manage the cut-offs is extremely scarce. The article is built on simple yet fundamental analytical explanations of scorecard performance dynamics, derived from practical experience. Results are backed by a numerical example, which shows the efficiency of different managerial decisions regarding cut-off setting in the paradox zone. The main conclusions are the following. In the most common case, the optimal reaction on model deterioration would be to counterintuitively narrow down the reject zone via cut-offs, which results in higher sales amount and even more increased risk ratios, but maximizes cash-flow in given conditions. This is the core of the scoring model deterioration paradox. It arises from the fact that when the scorecard deteriorates the high-risk segments of clients are actually becoming less risky and hence more profitable. This affects cut-offs, which must be applied to reject the riskiest loss-making segment of loan applications.

A Fundamental Explanation for the Size Premium in Returns and its Variation Over Time

A Fundamental Explanation for the Size Premium in Returns and its Variation Over Time

Grounding and the Existence of God

Abstract In this article, I seek to assess the extent to which Theism, the claim that there is a God, can provide a true fundamental explanation for the instantiation of the grounding relation that connects the various entities within the layered structure of reality. More precisely, I seek to utilise the explanatory framework of Richard Swinburne within a specific metaphysical context, a ground-theoretic context, which will enable me to develop a true fundamental explanation for the existence of grounding. And thus, given the truth of this type of explanation, we will have a further reason to believe in the existence of God.

FUNDAMENTALITY AND THE EXISTENCE OF GOD

In this article, I seek to assess the extent to which Theism, the claim that there is a God, can provide a true fundamental explanation for the existence of certain entities within the layered structure of reality. More precisely, I assume the cogency of Swinburne’s explanatory framework and seek to resituate it within a new philosophical context-that of the field of contemporary metaphysics-which will enable me to develop a true fundamental explanation for the existence of the non-fundamental entities that fill up the various levels of the layered structure of reality. And thus, given the truth of this type of explanation, we will have one more good reason to believe in the existence of God.

Grand Unified Origin of Gauge Interactions and Families Replication in the Standard Model

The tremendous phenomenological success of the Standard Model (SM) suggests that its flavor structure and gauge interactions may not be arbitrary but should have a fundamental first-principle explanation. In this work, we explore how the basic distinctive properties of the SM dynamically emerge from a unified New Physics framework tying together both flavor physics and Grand Unified Theory (GUT) concepts. This framework is suggested by a novel anomaly-free supersymmetric chiral E6×SU(2)F×U(1)F GUT containing the SM. Among the most appealing emergent properties of this theory is the Higgs-matter unification with a highly-constrained massless chiral sector featuring two universal Yukawa couplings close to the GUT scale. At the electroweak scale, the minimal SM-like effective field theory limit of this GUT represents a specific flavored three-Higgs doublet model consistent with the observed large hierarchies in the quark mass spectra and mixing already at tree level.

A statistical study of three-second foreshock ULF waves observed by the Magnetospheric Multiscale mission

We perform a statistical study of 3-s ultra-low frequency (ULF) waves using Magnetospheric Multiscale observations in the Earth's foreshock region. The average phase velocity in the plasma rest frame is determined to be anti-sunward, and the intrinsic polarization is right-handed. We further examine the linear instability conditions based on the drift-bi-Maxwellian distribution functions according to the observed plasma conditions. The resulting instability is a solution to the common dispersion equation of the ion/ion right-hand non-resonant and left-hand resonant instabilities. The predicted wave propagation is also predominantly anti-sunward. The cyclotron resonant conditions of the solar wind and backstreaming beam ions are evaluated, and we find that, in some cases, the anti-sunward propagating waves can be resonant with beam ions, which was overlooked in previous studies. The study suggests that the dispersion equation provides the 3-s ULF waves a fundamental explanation that unifies a rich variety of resonant conditions.

Is It Time to Forgo the Use of the Terms "Spin-Lattice" and "Spin-Spin" Relaxation in NMR and MRI?

Spin relaxation is one of the most fundamental concepts in magnetic resonance and is one of the key NMR "observables" providing critical motional information in chemical systems and, by extension, diagnostic information in clinical imaging. Yet, it can be difficult to find accurate conceptual descriptions of the two relaxation processes-longitudinal and transverse-in the NMR or MRI literature that explain why these processes are also referred to as "spin-lattice" and "spin-spin" relaxation, respectively. Often, the explanations provided in terms of energy levels, energy exchange, and the loss of phase coherence are inaccurate oversimplifications of quantum mechanical concepts and are thus incomplete and, at times, even contradictory. In fact, various texts still follow the terminology proposed >7 decades ago largely based on the theory of NMR in solids, even though it is clearly inadequate in the case of solution-state NMR. Here, we present the fundamental and quantum mechanical explanations of both relaxation processes in simple terms while clarifying and discussing the potential origins of some common confusions, nuances in the terminology, and seemingly contradictory definitions and explanations in the literature. Considering the issues with the old and inaccurate terminology, the consistent use of an alternate and more generally applicable terminology is proposed.

Smart survey on recent trends in water level, drought and water quality analysis system

Over 200 million yearly reports of diseases identified with scarce water and sanitation conditions, 5-10 million deaths occurred worldwide. Water quality checking has subsequently gotten important to supply clean and safe water. This survey work depicts the fundamental explanation behind the requirement for robust and productive Water level, Drought, and water quality control in the level framework, which will keep human assets healthy, sustainable and diminish water use for household purposes. Climate change and variability have so many significant impacts caused by the natural environment’s water system. Incredible methods, collection of water samples are tested alone and analyzed in water laboratories. However, it is not always easy to capture, analyze, and rapidly disseminate information to relevant users to make timely and well-informed decisions. The review work encompasses traditional methods based on Machine Learning (ML), and Deep Learning (DL) approaches.

Modeling and Characterization of the Ionic Conductivity of Proton-Exchange Membranes Based on Multiblock Copolymers of Sulfonated PSU/Ppsu Poly(Ether Sulfone)s

In this work, the ionic conductivity of proton-exchange membranes (PEMs) based on sulfonated multiblock copolymers composed of Polysulfone (PSU) and Polyphenylsulfone (PPSU) poly(ether sulfone) segments (SPSU/SPPSU) is evaluated. The copolymers were synthesized for the first time by polycondensation in a “one-pot two-step synthesis” of commercial monomers, followed by sulfonation reaction with trimethylsilyl chlorosulfonate (TMSCS) [1].The morphology of the membranes was examined by Field Emission Scanning Electron Microscopy (FE-SEM). Electrochemical Impedance Spectroscopy (EIS) was employed to measure the ionic conductivity of the membranes. The FE-SEM analysis of the samples revealed a random nanostructure of hydrophilic/hydrophobic domains with high and low content of ionic groups, respectively. Thus, no microphase separation was observed, even though the PSU block showed a greater affinity to be sulfonated. The ionic conductivity and water uptake of membranes with three different degrees of sulfonation, DS=0.45, 0.70 and 0.79, were characterized at 80 oC and relative humidities ranging from RH=10% to RH=100%. For a given RH, the ionic conductivity increased non-linearly with DS, showing a strong rise when DS was varied from 0.45 to 0.70, although the water uptake of the membranes remained nearly the same. In contrast, the increase of the ionic conductivity between DS=0.70 and DS=0.79 was significantly lower, but the water uptake increased sharply.The behavior of the membranes was modeled using percolation theory concepts. The numerical model was implemented in the finite volume-based code ANSYS Fluent [2,3]. The nanostructure of the membranes was divided into three types of sites in a random cubic network: sulfonated and well-hydrated sites, sulfonated and weakly hydrated sites and non-sulfonated sites (see Figure 1). The volume fraction of sulfonated sites was varied according to the DS of the samples, while the relative volume fraction of hydrated sites (i.e., the ratio between the volume fraction of hydrated sites and the volume fraction of sulfonated sites) was varied depending on RH. Isolated, hydrated sites not connected to the edges of the domain were removed from the network, since water was assumed to form a continuous network connected to the edges of the membrane according to the experimental conditions.Good agreement was found between the experimental data and numerical results, thus providing a fundamental explanation of the behavior of the multiblock copolymer membranes. The validated model will be used in future work to assist the design of high-performance and durable multiblock copolymer membranes for proton-exchange fuel cells, and related electrochemical devices.[1] N. Ureña, M.T. Pérez-Prior, C. del Río, A. Várez, J.Y. Sánchez, C. Iojoiu, B. Levenfeld, Multiblock copolymers of sulfonated PSU/PPSU Poly(ether sulfone)s as solid electrolytes for proton exchange membrane fuel cells, Electrochim. Acta 302 (2019) 428-440.[2] P.A. García-Salaberri, I.V. Zenyuk, J.T. Gostick, A.Z. Weber, Modeling Gas Diffusion Layers in Polymer Electrolyte Fuel Cells Using a Continuum-based Pore-network Formulation, ECS Trans. 97 (7) 615.[3] P.A. García-Salaberri, Modeling diffusion and convection in thin porous transport layers using a composite continuum-network model: Application to gas diffusion layers in polymer electrolyte fuel cells, Int. J. Heat Mass Trans. (2020), accepted.. Figure 1. Random cubic network composed of sulfonated and well-hydrated sites, sulfonated and weakly hydrated sites and non-sulfonated sites used to model the ionic conductivity of the multiblock copolymer membranes.. Figure 1

Molecular Polaritons Generated from Strong Coupling between CdSe Nanoplatelets and a Dielectric Optical Cavity.

We demonstrate the formation of CdSe nanoplatelet (NPL) exciton-polaritons in a distributed Bragg reflector (DBR) cavity. The molecule-cavity hybrid system is in the strong coupling regime with an 83 meV Rabi splitting, characterized from angle-resolved reflectance and photoluminescence measurements. Mixed quantum-classical dynamics simulations are used to investigate the polariton photophysics of the hybrid system by treating the electronic and photonic degrees of freedom (DOF) quantum mechanically and the nuclear phononic DOF classically. Our numerical simulations of the angle-resolved photoluminescence (PL) agree extremely well with the experimental data, providing a fundamental explanation of the asymmetric intensity distribution of the upper and lower polariton branches. Our results also provide mechanistic insights into the importance of phonon-assisted nonadiabatic transitions among polariton states, which are reflected in the various features of the PL spectra. This work proves the feasibility of coupling nanoplatelet electronic states with the photon states of a dielectric cavity to form a hybrid system and provides a new platform for investigating cavity-mediated physical and chemical processes.

Experimental investigation on the dynamic responses of vented hydrogen explosion in a 40-foot container

To investigate the structural dynamics of a container subjected to a vented hydrogen explosion, 48 field tests were conducted in a 40-foot container with roof vents and an end vent. The effects of the hydrogen concentration, ignition position, and obstacles on the evolution of the dynamic responses were investigated. Three stages were generally observed for displacements: (1) At the stage of the vent rupture, the displacement could be approximated as a quasi-static response, and there was a linear relationship between the peaks of positive overpressure and displacement. (2) Structural deformation appeared as reciprocating vibration at the stage of Helmholtz oscillation. (3) The structure exhibited relatively weak irregular fluctuation when high-frequency acoustic oscillation occurred. Two types of the structural acceleration with low and high amplitudes resulting from Helmholtz oscillation and acoustic oscillation, respectively, were clearly observed. For the end-vented explosion, multiple peaks were observed for the displacement at the quasi-static stage due to the rupture, discharge, and external explosion. Moreover, the displacement was sensitive to hydrogen concentration, whereas the number of obstacles and the ignition position had significant influences on the peak acceleration for roof venting. This work conducted the fundamental explanation for the evolution law of structural responses induced by vented hydrogen explosions from the perspective of structural dynamics and enriched the experimental accumulation in a large-scale container with congestion in this field.

Constraint-induced intervention as an emergent phenomenon from synaptic competition in biological systems

The principle of constraint-induced therapy is widely practiced in rehabilitation. In hemiplegic cerebral palsy (CP) with impaired contralateral corticospinal projection due to unilateral injury, function improves after imposing a temporary constraint on limbs from the less affected hemisphere. This type of partially-reversible impairment in motor control by early brain injury bears a resemblance to the experience-dependent plastic acquisition and modification of neuronal response selectivity in the visual cortex. Previously, such mechanism was modeled within the framework of BCM (Bienenstock-Cooper-Munro) theory, a rate-based synaptic modification theory. Here, we demonstrate a minimally complex yet sufficient neural network model which provides a fundamental explanation for inter-hemispheric competition using a simplified spike-based model of information transmission and plasticity. We emulate the restoration of function in hemiplegic CP by simulating the competition between cells of the ipsilateral and contralateral corticospinal tracts. We use a high-speed hardware neural simulation to provide realistic numbers of spikes and realistic magnitudes of synaptic modification. We demonstrate that the phenomenon of constraint-induced partial reversal of hemiplegia can be modeled by simplified neural descending tracts with 2 layers of spiking neurons and synapses with spike-timing-dependent plasticity (STDP). We further demonstrate that persistent hemiplegia following unilateral cortical inactivation or deprivation is predicted by the STDP-based model but is inconsistent with BCM model. Although our model is a highly simplified and limited representation of the corticospinal system, it offers an explanation of how constraint as an intervention can help the system to escape from a suboptimal solution. This is a display of an emergent phenomenon from the synaptic competition.

Functional theory for Bose-Einstein condensates

One-particle reduced density matrix functional theory would potentially be the ideal approach for describing Bose-Einstein condensates. It namely replaces the macroscopically complex wavefunction by the simple one-particle reduced density matrix, therefore provides direct access to the degree of condensation and still recovers quantum correlations in an exact manner. We eventually initiate and establish this novel theory by deriving the respective universal functional $\mathcal{F}$ for general homogeneous Bose-Einstein condensates with arbitrary pair interaction. Most importantly, the successful derivation necessitates a particle-number conserving modification of Bogoliubov theory and a solution of the common phase dilemma of functional theories. We then illustrate this novel approach in several bosonic systems such as homogeneous Bose gases and the Bose-Hubbard model. Remarkably, the general form of $\mathcal{F}$ reveals the existence of a universal Bose-Einstein condensation force which provides an alternative and more fundamental explanation for quantum depletion.

Applying Government Schemes in Rural Sectors Prediction System for Evaluation of Data Science Algorithm

The administration dispatches different aggressive projects attempting to make the nation more prosperous, yet what they bomb is in fruitful execution and coming to recipients. The fundamental explanation for this issue is the absence of mindfulness among rustic individuals. This paper is to give an answer for this uninformed circumstance. Through this framework the rustic understudies will be instructed such that they can become acquainted with about what are the different plans that are outfitted by the administration and what are the plans they are qualified for. On the off chance that the country understudies came to know and get mindful of the apparent multitude of legislative plans gave by the Government of India for the government assistance of the provincial understudies, at that point their life would venture into next level. At first this framework will investigate the accessible government plans in the instructive for the government assistance of country understudies. Next, the understudy’s information ((i.e.) name, age, station, occupation, annualincome.etc) are accumulated. At that point; both the datasets are brought into the Anaconda Navigator. At that point, investigation and grouping dependent on networks (SC, ST, BC and MBC) of the understudies and the plans are performed. At that point utilizing the forecast calculations (Naïve Bayes, Random Forest and Support Vector Machine (SVM)) what are generally the plans the specific understudy is qualified for are anticipated. An investigation is made on the proficiency of the three calculations. The exactness of the three calculations is broke down and the effective calculation which creates the outcome with most elevated precision is at last used to play out the forecast of the plans that a specific understudy is qualified for. At long last, the anticipated plans anticipated utilizing the most elevated effective calculation among the three calculations will be gotten back to the understudies. Hence, through this undertaking the rustic understudies will come to think about different recipient plans gave by government and they can use those plans for the improvement of the country environmental factors.

Fundamental evaluation of the effect of pipe diameter, loop length and local losses on steady-state single-phase natural circulation in square loops using the 1D network code Flownex

In this study, steady-state single-phase natural circulation of water in square loops is simulated using a 1D network code. Fundamental explanations are given for the behaviour of the buoyancy force and mass flow rate. The methodology and model are validated by the very good agreement with the generalized correlation of the predicted steady-state Reynolds numbers, as a function of the modified Grashof numbers and loop geometry numbers. For a given pipe diameter and loop length, it is shown that the mass flow rate and buoyancy force increases when the power increases. However, due to the effect of the increase in the mass flow rate, the actual increase in the temperature rise over the heater, which is responsible for the buoyancy force, is only 66% of that associated with the increase in the power. Increasing the pipe diameter increases the mass flow rate significantly and decreases the buoyancy force decreases markedly, due to the significant decrease in the frictional resistance. For a given power and pipe diameter, when no local losses are assumed, the mass flow rate is independent of the loop length. When local losses are accounted for, the mass flow rate, however, increases with increasing loop length until it reaches an asymptotic value equal to the mass flow rate for no local losses. For a given power, pipe diameter and loop length, the mass flow rate increases when the inlet temperature increases, due the non-linear nature of the density of the water as a function of temperature.

Fizička priroda "anomalnih" elektrona u visoko-vakuumskim diodama

Introduction/purpose: A fundamental theoretical explanation is given for the fact that in subnanosecond vacuum diodes there exists a group of electrons with kinetic energies much higher than the applied voltage (multiplied by the value of the elementary charge) qUmax. Methods: A mathematical method is used based on the numerical solution of the Vlasov-Poisson differential equations system for one-dimensional vacuum diodes of various designs. Results: It is shown in detail that the so-called "anomalous" electrons appear in the transient time domain characterizing the processes of establishing current flow in vacuum diodes. Conclusion: It has been convincingly shown that the presence of "anomalous" electrons is not associated with either the diode design or the presence of additional current carriers. In vacuum diodes with a subnanosecond leading edge of the voltage pulse, the excess of energy over qUmax can be over 20%.

Exploration of physicochemical properties and molecular interactions between cellulose and high-amylose cornstarch during extrusion processing

Incorporating fiber at high levels (>10%) into direct-expanded products with acceptable texture is challenging. Fundamental explanations for the interaction of starch and fiber and the cause of expansion reduction need further understanding for the effective incorporation of fiber into expanded products. This study aims to explain how cellulose content impacts the physicochemical properties of starch-based extrudates and the long-range and short-range molecular changes of starch. Mixtures of cornstarch (50% amylose) and cellulose were extruded using a co-rotating twin-screw extruder. Thermal and pasting properties of the raw mixtures were evaluated, and the physicochemical properties and microstructure of extrudates were determined. Long-range and short-range molecular changes of starch-cellulose mixtures before and after extrusion were observed by X-ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy. The expansion ratio of extrudates reduced significantly as the cellulose content increased and had a strong negative correlation with crystallinity. Cell structures of starch-cellulose extrudates had a smaller and more uniform pore size but possessing a more ruptured matrix. FTIR spectra suggested that there was no covalent bonding interaction between starch and fiber after extrusion. Extrusion reduced the overall crystallinity compared to the raw mixtures. XRD showed that the crystallinity of the starch-cellulose extrudates increased as the cellulose content increased, and the XRD peaks representing cellulose remained unchanged. Cellulose could interfere with starch chain reassociation through intermolecular hydrogen bonding during the expansion process. Phase separation of starch and cellulose is likely to occur at high cellulose content, which could be another reason for the reduced expansion.