Reasonable Boundary Research Articles

Pore interconnectivity and surface accessibility in stiffened mixed linker MOFs: An investigation using variable energy positron spectroscopy

Zeolitic imidazolate framework-8 (ZIF-8) based membranes show poor selectivity for gas separation due to flexibility of the frameworks. Mixed linker frameworks (ZIF-7x-8) membranes are shown to have higher separation selectivity and low permeance of gases. In order to investigate the role of pores' interconnectivity and surface accessibility towards gases’ permeance and selectivity, variable energy positron spectroscopy (VEPS) measurements have been carried out for ZIF-7x-8 (x ​= ​0, 20.6, 52.6, 79.4, 90.4, 97.2 and 100%) membranes. These membranes were deposited using fast current driven synthesis method to produce a stiffened phase (Cm) of ZIF-8. The frameworks have been characterized using XRD, FTIR, Raman spectroscopy and FE-SEM for their crystalline structure, chemical bonding and morphology. Depth dependent Doppler broadening measurements using VEPS show distinct variations in S-E and 3γ/2γ-E profiles of the membranes. The positronium diffusion length determined by fitting of S-E profiles considering a diffusion model shows a drastic reduction in pore interconnectivity and their surface accessibility for x ​= ​20–97%. These modifications explain the reduction in gas permeance of ZIF-7x-8 based membranes. The present study confirms that membranes having x∼20% shows higher selectivity due to their ZIF-8_Cm crystal structure, reasonable pore interconnectivity and limited non-selective grain boundary structure diffusion.

SMaRT Assessment Tool: An Innovative Approach for Objective Assessment of Flap Designs.

The teaching and assessment of ideal surgical markings for local flaps required for optimal aesthetic and functional outcomes remain a challenge in the present era of competency-based surgical education. The authors utilized the bilobed flap for nasal reconstruction as a proof of concept for the development of an innovative objective assessment tool based on statistical shape analysis, with a focus on providing automated, evidence-based, objective, specific, and practical feedback to the learner. The proposed tool is based on Procrustes statistical shape analysis, previously used for the assessment of facial asymmetry in plastic surgery. For performance boundary testing, a series of optimal and suboptimal designs generated in deliberate violation of the established ideals of optimal bilobed flap design were evaluated, and a four-component feedback score of Scale, Mismatch, Rotation, and Translation (SMaRT) was generated. The SMaRT assessment tool demonstrated the capacity to proportionally score a spectrum of designs (n = 36) ranging from subtle to significant variations of optimal, with excellent computational and clinically reasonable performance boundaries. In terms of shape mismatch, changes in SMaRT score also correlated with intended violations in designs away from the ideal flap design. This innovative educational approach could aid in incorporating objective feedback in simulation-based platforms in order to facilitate deliberate practice in flap design, with the potential for adoption in other fields of plastic surgery to automate assessment processes.

‘Doctors can’t be doctors all of the time’: a qualitative study of how general practitioners and medical students negotiate public-professional and private-personal realms using social media

ObjectiveThe objective of this study is to explore the experiences and perspectives of general practitioners’ and medical students’ use of, and behaviour on, social media and to understand how they...

Digital Dependence of Higher Education Evaluation: Challenges and Resolutions

The Digital dependence in this study is not a dependency on the Internet in traditional contexts. The digital dependence of higher education evaluation has the following manifestations: The widespread penetration of "digit" exists everywhere in higher education evaluation; “Digit” takes up the priority within the coordinate system of higher education evaluation; Irrational "digit" becomes disciplinary force by alienation in higher education evaluation. Its roots in the fact that it derives from the long-term restriction by the evaluation views on rationalism under the control of technological rationality, the promotion of simplifying perception of the higher education field, and the resource black hole and benefit inducement that "digit" can be manifested. Therefore, the key to eliminate the digital dependence in higher education evaluation and breaking the utilitarian thinking should include the following three aspects: returning the meaning of digital criterion in higher education evaluation to be genuine, clarifying the reasonable boundaries of the digital application in the evaluation of higher education, and optimizing the structure of the higher education evaluation system.

A New Method Based on Boundary Element Method to Appraise CO2 Geological Storage Potential in Depleted Shale Gas Reservoirs

In recent years, greenhouse gases have increased in the atmosphere, and climate change concerns have triggered global efforts to find solutions for CO2 capture, separation, transport, and storage. Geological sequestration in the depleted unconventional reservoir is an effective measure to reduce the atmosphere’s CO2 content. The exact evaluation of the CO2 storage capacity can verify the feasibility of storing carbon dioxide and parameter optimization. A reasonable boundary element method to estimating the CO2 storage capacity of depleted shale gas reservoirs considering arbitrarily shaped boundaries is introduced. Firstly, the physical model with fracture networks is built based on the microseismic data. Then, the flow equation including the matrix and fracture can be obtained considering adsorption, and the star-delta transformation is used to deal with interconnected fracture segments. The point source function with an infinite boundary can be obtained after the Laplace transform method. Finally, the semianalytical flow solution is obtained by using the boundary element method in the Laplace region. Moreover, the results have a high agreement with commercial software for the regular boundary. The sensitivity of relevant parameters is analyzed by this method, and the importance of considering the boundary shape is emphasized. This method can evaluate the CO2 storage capacity of formation with the irregular boundary and is regarded as the guide of parameter optimization in CO2 storage.

Numerical investigation of the breakup mode and trajectory of liquid jet in a gaseous crossflow at elevated conditions

ABSTRACTThe commercial Computational Fluid Dynamics (CFD) software STAR-CCM+ was used to simulate the flow and breakup characteristics of a Liquid Jet Injected into the gaseous Crossflow (LJIC) under real engine operating conditions. The reasonable calculation domain geometry and flow boundary conditions were obtained based on a civil aviation engine performance model similar to the Leap-1B engine which was developed using the GasTurb software and the preliminary design results of its low-emission combustor. The Volume of Fluid (VOF) model was applied to simulate the breakup feature of the near field of LJIC. The numerical method was validated and calibrated through comparison with the public test data at atmospheric conditions. The results showed that the numerical method can capture most of the jet breakup structure and predict the jet trajectory with an error not exceeding ±5%. The verified numerical method was applied to simulate the breakup of LJIC at the real engine operating condition. The breakup mode of LJIC was shown to be surface shear breakup at elevated condition. The trajectory of the liquid jet showed good agreement with Ragucci’s empirical correlation.

Diffeomorphic shape evolution coupled with a reaction-diffusion PDE on a growth potential

This paper studies a longitudinal shape transformation model in which shapes are deformed in response to an internal growth potential that evolves according to an advection reaction diffusion process. This model extends prior works that considered a static growth potential, i.e., the initial growth potential is only advected by diffeomorphisms. We focus on the mathematical study of the corresponding system of coupled PDEs describing the joint dynamics of the diffeomorphic transformation together with the growth potential on the moving domain. Specifically, we prove the uniqueness and long time existence of solutions to this system with reasonable initial and boundary conditions as well as regularization on deformation fields. In addition, we provide a few simple simulations of this model in the case of isotropic elastic materials in 2D.

The Influence of the Instantaneous Collapse of Tailings Pond on Downstream Facilities

To evaluate the evolutionary processes guiding the formation of the tailings-water mixtures produced by the instantaneous collapse of tailings ponds and the influence of these on downstream facilities, a 2D simulation model with reasonable boundary and working conditions derived from actual engineering practice was built in this study, and the relationship between dam-break elevation and impact on downstream facilities was also analyzed to determine the relevant mechanism of influence. Computational results indicated that lowering the dam-break elevation caused the maximum velocity and flooding depth, along with the flooded area at monitoring points, to gradually increase. The occurrence times of maximum velocity and flooding depth were also gradually moved forward as the breaking elevation was reduced; this effect is directly related to the increase in the total potential energy at the lower break elevations. Further simulations of sand-prevent dams with different heights located downstream from a tailings pond were carried out to identify methods for mitigating the impact of dam failure. The results revealed that increasing the height of the sand-prevent dam reduced the production of tailings mixtures. Based on the results, the construction of a sand-prevent dam with a crest elevation equal to that of the starter dam was recommended.

Study on the Shape Optimization of Composite Slope at the End of Irregular Boundary Open-Pit Mine

In order to optimize the shape of the compound slope at the end of the open-pit mine under the condition of non-irregular boundary, the compound slope composed of the stope end and the inner dump in the south of the open-pit mine in Pingshuo is studied. Due to the impact of land acquisition, the space of external dump is seriously insufficient, and with the development and change of mining engineering and the influence of geological structure, the problem of compound form optimization and the release and utilization of internal drain space in the south side is generated. Through field investigation and theoretical analysis and numerical analysis method, on the basis of investigating the ore party production status, to establish a 3 d geological model, select two battery profile typical position, using rigid body limit equilibrium method from the perspective of 2 d, in the full study south help shrink battery limit compound stope side slope and mine safety distance, flat width, and the direction of dump active line and the relationship between the stability design of multiple slope configuration scheme, through the various methods of slope stability, enforceability and comparing some important parameters such as displacement capacity, ultimately determine the technology feasible economic and reasonable boundary zone composite slope space form. Based on the above research results, FLAC3D software was used to study the stress-strain relationship inside the slope, revealing the deformation and failure mechanism and stability of the composite slope in the south bound area. The results show that the landslide mode and stability of the composite slope in the south bound area of pingshuoAndaobao open-pit coal mine are mainly controlled by the safe distance between stope and dump and the weak layer of 11 coal floor. According to the design, the economic and reasonable parameters of the composite slope in the south slope shrinkage boundary area are as follows: the safe distance between the stope end side and the dump site is 50m, the width of the dump flat plate is 60m, and the working line Angle of the dump line with the abandonment height of 255m is 125°, the total discard space was95,934,100 m3.

Dust-suppression and cooling effects of spray system installed between hydraulic supports in fully mechanized coal-mining face

Spray systems installed between hydraulic supports are crucial for suppressing the dispersion of coal dust at fully mechanized coal-mining faces, and evaporative cooling by water spray is increasingly being applied to enhance thermal comfort in built environments. Hence, this study proposes the installation of a spray system between hydraulic supports to perform dust suppression and cooling at a fully mechanized coal-mining face. An experimental platform is established to perform the spray experiments and thereby obtain reasonable and reliable boundary conditions for the numerical simulation. The physical parameters of the rotary solid cone-shaped wide-angle nozzles (featuring an aperture of 2 mm and an “X" guiding core) are measured at different spray pressures (2, 4, 6, and 8 MPa). The atomization effects of the spray system under various pressures are studied using numerical simulations. The results indicate that when the spray pressure is 6 MPa, the droplet can prevent dust suppression on the working face, thereby effectively preventing dust diffusion. In addition, the air temperature distributions around the working face at different spray-water temperatures are obtained. The most economical water temperature and effective cooling distance of the spray system are determined as 283 K and 10 m, respectively. Finally, a multigroup spray system arrangement is proposed. The field temperature measurement results verify the cooling effect. This study provides an alternative solution for dust suppression and cooling engineering around hot mining faces.

Thick-Wall Elastic Collapse for Casing Design

Summary Elastic collapse is an important piece of the tubular collapse formulation in API TR 5C3 (2008) and ISO/TR 10400 (2007). Elastic collapse is significant because it is independent of the strength of the tubing; for example, K-55 and Q-125 have the same resistance to elastic collapse. Advanced collapse models, such as Klever and Tamano (2006), require a thick-wall collapse result as part of their formulation. What effect would a thick wall have on elastic collapse? There really is no way to tell from the classic formulation. The primary issue is whether the elastic collapse formula overpredicts or underpredicts collapse pressure. The developers of the API collapse equation thought the thin-wall equation overpredicted collapse pressure and put in terms to reduce the predictions. Other studies suggested the opposite effect. What is needed is a formulation that is based on an elastic solution for a thick-wall cylinder, but that can derive the classic solution for a thin wall. The elastic equations for a thick-walled cylinder exist, known as the Kirsch equations (Kirsch 1898). A new set of physically reasonable boundary conditions is proposed for the Kirsch equation, which is then used to determine the collapse resistance for a thick-wall pipe. This result also yields the classic result in the limit as t/D becomes small. The thick-wall elastic collapse formula is then applied to the standard API TR 5C3 (2008) collapse formulation and to the Klever-Tamano formulation (Klever and Tamano 2006).

Gas-solid Erosion Wear Characteristics of Two-phase Flow Tee Pipe

Particles erosion wear always consist in the intersection of tee pipe, which is an inevitable problem. In order to obtain the erosion wear characteristics of two-phase flow tee pipe, several cases of different inlet diameters are investigated numerically in this paper. Euler-Lagrange method is adopted to describe the gas-solid two-phase flow and the finite volume method is adopted to solve the erosion results. Meshing O-type grids to obtain the reasonable boundary layer in ICEM CFD. By verifying and comparing the turbulence intensity and velocity of the six meshes, a reasonable finite element model is selected. Intersection, the severest erosion region, is the location where the gas flow direction changes. The inlet diameter determines the region of the impact particles directly hitting the wall. When the inlet diameter is smaller, the erosion of the intersection is severer. As the inlet velocity increases, both the erosion of the intersection and the outlet pipe become severer. However, there are only the erosion scars at the intersection are affected, with the increase of particle mass flow.

Performance characteristics and working fluid selection for high-temperature organic Rankine cycle driven by solar parabolic trough collector

Abstract In present paper, thermodynamic analysis and techno-economic assessment of an organic Rankine cycle (ORC) coupled with solar parabolic trough collector (PTC) are investigated. The thermodynamic and economic models, based on the principles of thermodynamics and heat transfer, as well as dynamic economic analysis, are developed for the components of the combined system. By performing a parametric study, the effects of outlet temperature (TPTC,out) and temperature difference between inlet and outlet of PTC (ΔT) and pinch point temperature difference of heat exchangers on the thermo-economic performance are evaluated. Moreover, under reasonable thermodynamic boundary conditions, the optimal operational parameters are obtained via a Pareto frontier solution. It is indicated that the improving TPTC,out is beneficial to the thermo-economic performance. Among the fluid candidates, toluene yields the best energy, exergetic and economic performance. There exists an optimal ΔT at which the thermal and exergy efficiency achieve the maximum. The optimal ΔT is 19–26°C for the screened working fluids. The pinch point temperature difference of evaporator has different impact on the system performance compared with that of condenser. The evaporator pinch point temperature difference has slight influence on the economic performance when it is larger than 10°C. While there is optimized condenser pinch point temperature difference (7–8°C), the economic performance is the optimal. The PTC and heat exchanger are the main source of total investment cost, account for more than 75%. The Pareto frontier solutions can provide a design guide for the decision maker.

Statistical Indoor Exclusion Zone Analysis by Investigating Electromagnetic Fields inside a Nuclear Power Plant

This article investigates a statistical indoor exclusion zone (EZ) that can be efficiently applied to a nuclear power plant (NPP) by examining electromagnetic fields inside the actual NPP. To obtain the statistical indoor EZ, the indoor environment of the Korea Institute of Nuclear Safety (KINS) simulator room is modeled using the Wireless InSite commercial electromagnetic simulation software. The indoor space around the transmitting antenna is classified as multiple observation regions, and the EZ boundaries of each region are independently defined within each separate observation region. The EZ boundaries are then obtained using a margined regression model, which makes it possible to determine a reasonable boundary of the statistical indoor EZ. To validate the statistical indoor EZ, the received power inside the KINS simulator room is then measured, which agrees well with the simulated results. The results demonstrate that the proposed statistical indoor EZ can be properly obtained not only from the simulation data but also from the measurement data.

The Model Construction and Path Exploration of Ruling by Law

From the time when it came to power, the Chinese Communist Party’s mode of governance has shifted from "ruling according to policies" to "ruling according to law." Domestic scholars have done a lot of discussion on the basic connotation and related concepts of governing by law. Most of these theoretical discussions are static and are an analysis and explanation of the actual situation. The Communist Party’s ruling turn is an inevitable choice of regularity within the ruling logic, and more of a dynamic choice. The study of the logic of governing by law can more clearly discover the law of development followed by the Communist Party's way of governing. After this static analysis, the development route within the logic can be extracted. Combining the research results of academia, construct a dynamic mode of governing by law, find the subject, object and development path of governing by law, so as to clarify the reasonable boundary of civil rights, party power and political power, coordinate the development relationship among the masses, political parties and the state, and standardize The progressive process of the will of the people, the will of the party, and the will of the state.

Design, measurement, and characteristic analysis of uncertainty indices for education fiscal policies: a case study of China

Since the release of “4%” objective of fiscal educational expenditure to GDP in 2012, the Chinese governments at all levels have frequently formulated or changed education finance policy in light of the complex situation of China’s economic development. The policy changes have ensured the steady growth of education financial investment, but also brought a series of unknown or uncertain factors to the allocation of educational resources. According to the text context from the selected mainstream Chinese media in the past two decades, this study creates a newspaper-based policy uncertainty indices of China’s education fiscal policy under the framework of Baker (JAMA 131(4):1593–1636, 2016)'s study. We also apply the EGARCH model to test the robustness of the results. Our findings reveal that the uncertainty indices are highly consistent with the fluctuation of education fiscal policy in various stages in China. It suggests that the government sectors should define the reasonable boundaries of the "tangible hand" and harden the budget in the process of allocating education resources, to eliminate the negative impact brought by the uncertainty of education fiscal policy. Moreover, this study puts forward the research prospect of the application of policy uncertainty in the field of education.

Reasonable application range of flocculation–solidification combined method in treatment of hydraulically dredged mud slurry

An improved method, i.e., flocculation–solidification combined method (FSCM), has been developed for building a working platform more efficiently at the surface of newly reclaimed ground filled with hydraulically dredged mud slurry at extra high water content (EHW-MS). Previous experimental results have demonstrated the significant superiority of FSCM over conventional pure cement solidification method (PCSM) under some application conditions. This study focuses on further clarifying the reasonable boundary for the application conditions, i.e., identifying the reasonable application range, of FSCM in EHW-MS treatment. A number of laboratory experiments are performed to characterize the deposition and strength gain behavior of FSCM or PCSM treated EHW-MS samples with various values of the equivalent initial water content (w ei) and Atterberg limits. The deposition and strength characteristics resulting from FSCM and PCSM are then compared comprehensively to illustrate the influence of w ei and Atterberg limits on the superiority of FSCM over PCSM. Results indicate well that FSCM shows more significant superiority over PCSM with the increase of either w ei or Atterberg limits, and plastic limit > 14 (or liquid limit > 23) and w ei > 232% can be considered as the reasonable application range of FSCM in EHW-MS treatment, within which the solidification efficiency of FSCM is at least 1.20 times higher than that of PCSM.

Parameterized meso-scale modeling and experimental study on the tensile damage evolution and strength of 3D five-directional braided composites

A parametric finite element model (FEM) of three-dimensional five-directional (3D5d) braided composites was established considering the yarn space contact relationship. By adopting reasonable damage criteria and boundary conditions, the damage behavior and mechanical properties of FEM under tensile loading were investigated. The finite element prediction results are consistent with the experiments, indicating that the FEM can effectively predict the progressive damage and strength of 3D5d braided composites. Damage evolution shows that the main failure modes with small braiding angles include tensile failure of braiding yarn and axial yarn, while the large braiding angles are tensile shear failure of braiding yarn. As the fiber volume fraction increases, the initial damage location of the FEM changes from the intersection of braiding yarn/axial yarn to the junction among the braiding yarns. The stress-strain curves results show that the 3D5d braided composites exhibit brittle fracture characteristics under longitudinal tensile loading, and the mechanical properties are significantly correlated with the braiding angle and fiber volume fraction. In addition, the tensile properties of 3D5d braided composites are also compared with those of three-dimensional four-directional (3D4d) braided composites.

The Ethical Community in Kant’s Pure Rational System of Religion: Comments on Rossi’s The Ethical Commonwealth in History

This commentary on Rossi’s The Ethical Commonwealth in History will address three points of interpretation related to Kant’s conception of the ethical community/commonwealth (ethischen gemeinen Wesen). First, I will raise a number of concerns related to Rossi’s use of Kant’s concept of the highest good. Second, I will examine the relevance of the overall project of Kant’s Religion within the Boundaries of Mere Reason to his discussion of the ethical community, a matter that Rossi does not take up. Third, I will challenge the optimism that Rossi assigns to Perpetual Peace in light of its closing “antinomy between politics and morals.”

‘Fear and Trembling’ Reconsidered in Light of Kant’s ‘Groundwork of the Metaphysics of Morals’

In this study I provide a thematic comparison of Soren Kierkegaard’s Fear and Trembling and Immanuel Kant’s Groundwork of the Metaphysics of Morals to suggest that the representation of the ethical in Fear and Trembling is transparently Kantian. At times I draw on Kant’s Religion Within the Boundaries of Mere Reason, Conflict of the Faculties, and The Metaphysics of Morals to offer a comprehensive account of Kant’s ethical theory. Both philosophers hold profoundly important positions within the milieu of ethics, however they have always shared a tenuous and at times negative relationship. In this study, I challenge such commentators by showing that when the figure of Abraham is taken typologically and excluded from the text, what emerges from Fear and Trembling is a Kantian based ethics. I argue that a comparative reading of Kant’s Groundwork and Kierkegaard’s Fear and Trembling reveals that Kierkegaard’s thought gravitates towards three central principles of Kant’s categorical imperative, as well sharing some similarities with Kant’s understanding of duty.