Miracle-dz/UniFAR-FTUs huggingface dataset:
The bypass transition mechanism of the Stokes boundary layer in the intermittently turbulent regime

This numerical study focuses on the coherent structures and bypass transition mechanism of the Stokes boundary layer in the intermittently turbulent regime. In particular, the initial disturbance is produced by a temporary roughness element that is removed immediately after triggering a two-dimensional vortex tube under an inflection-point instability. The present study reveals a complete scenario of self-induced motion of a vortex tube after rollup from the boundary layer. The trajectory of the vortex tube is reasonably described based on the Helmholtz point-vortex equation. The three-dimensional transition of the vortex tube is attributed to the Crow instability, which leads to a sinusoidal disturbance that eventually evolves into a ring-like structure, especially for the weaker vortex. Further investigation demonstrates that three-dimensional or quasi-three-dimensional vortex perturbations in the free stream play a critical role in the boundary layer transition through a bypass mechanism, which is featured by the non-modal and explosive transient growth of the subsequent boundary layer instabilities. This transition scenario is found to be analogous to the oblique transition in the steady boundary layer, both of which are characterised by the formation of streaks, rollup of hairpin-like vortices and burst into turbulent spots. In addition, the streamwise propagation of turbulent spots is discussed in detail. To shed more light on the nature of the intermittently turbulent Stokes boundary layer, a conceptual model is proposed for the periodically self-sustaining mechanism of the turbulent spots based on the present numerical results and experimental evidence reported in the literature.
Growth in Cities

Recent theories of economic growth, including those of Romer, Porter, and Jacobs, have stressed the role of technological spillovers in generating growth. Because such knowledge spillovers are particularly effective in cities, where communication between people is more extensive, data on the growth of industries in different cities allow us to test some of these theories. Using a new data set on the growth of large industries in 170 U.S. cities between 1956 and 1987, we find that local competition and urban variety, but not regional specialization, encourage employment growth in industries. The evidence suggests that important knowledge spillovers might occur between rather than within industries, consistent with the theories of Jacobs.
FPGA implementation of variable precision Euclid’s GCD algorithm

Introduction: Euclid's algorithm is well-known for its efficiency and simple iterative to compute the greatest common divisor (GCD) of two non-negative integers. It contributes to almost all public key cryptographic algorithms over a finite field of arithmetic. This, in turn, has led to increased research in this domain, particularly with the aim of improving the performance throughput for many GCD-based applications. Methodology: In this paper, we implement a fast GCD coprocessor based on Euclid's method with variable precisions (32-bit to 1024-bit). The proposed implementation was benchmarked using seven field programmable gate arrays (FPGA) chip families (i.e., one Altera chip and six Xilinx chips) and reported on four cost complexity factors: the maximum frequency, the total delay values, the hardware utilization and the total FPGA thermal power dissipation. Results: The results demonstrated that the XC7VH290T-2-HCG1155 and XC7K70T-2-FBG676 devices recorded the best maximum frequencies of 243.934 MHz down to 39.94 MHz for 32-bits with 1024-bit precisions, respectively. Additionally, it was found that the implementation with different precisions has utilized minimal resources of the target device, i.e., a maximum of 2% and 4% of device registers and look-up tables (LUT’s). Conclusions: These results imply that the design area is scalable and can be easily increased or embedded with many other design applications. Finally, comparisons with previous designs/implementations illustrate that the proposed coprocessor implementation is faster than many reported state-of-the-art solutions. This paper is an extended version of our conference paper [1].
Analyzing the Content of Reading Texts Questions in Flying High for Saudi Arabia

This study aimed at analyzing the cognitive levels of the wh-questions following the reading texts in the Students’ Book of Flying High for Saudi Arabia One. A Checklist based on the revised cognitive domain of Bloom’s Taxonomy was the instrument used to categorize the cognitive levels of these questions and to determine to what extent they are included properly in the Student’s Book of Flying High for Saudi Arabia One. The main findings revealed that the wh-questions following the reading texts which are included in the textbook under analysis were not properly included. Also, the authors of the textbook overemphasized the lower thinking skills and neglected higher thinking skills. Such study is recommended to shed light upon the role of the other series of Flying High for Saudi Arabia in developing cognitive skills among secondary Saudi students.
Method for Quantifying Supply and Demand of Construction Minerals in Urban Regions—A Case Study of Hanoi and Its Hinterland

Urbanization is a global trend: Since 2007 more than 50% of the world’s population have been living in urban areas, and rates of urbanization are continuing to rise everywhere. This growth in urbanization has led to an increased demand for natural resources, in particular non-metallic minerals such as stones, sand and clay, which account for one third of the entire flow of materials. Generally, these materials are traded within regional markets. This close geographical link between the demand for building materials in urban areas and the material supply in the hinterland leads to massive interventions in the natural environment and landscape. These urban–rural linkages can be revealed by applying Material Flow Analysis (MFA) to the built environment in order to trace the flows of building materials. The objective of this paper is to present a method for quantifying regional material flows by considering the supply and demand of building materials. This will be applied to the Vietnamese case study area of Hanoi and its hinterland province Hoa Binh. The results indicate a consumption of almost 60% of the construction mineral reserves in total secured by planning in the hinterland province considering a period of 15 years. However, this does not allow for the general conclusion that raw materials are sufficiently available. The sand reservoirs are only sufficient for eight years and clay reserves are used up after four years. This increases the need to exploit further raw material reserves, which are becoming increasingly scarce and results in stronger interventions in nature In order to safeguard the hinterland from the negative impacts of urbanization, a new understanding of resource efficiency is needed—one that acknowledges both resource efficiency in the construction of urban structures and appropriate resource conservation in the provision of the raw materials from the hinterland. This will require the creation of new integrated planning approaches between urban and regional planning authorities. Regional MFA is one way of realising such an approach.
High Mortality and Low Net Change in Live Woody Biomass of Karst Evergreen and Deciduous Broad-Leaved Mixed Forest in Southwestern China

Repeated observation based on large permanent monitoring plots is a key method for directly understanding forest regeneration dynamics. Karst forests grow slowly in adverse habitats and possess a special regeneration mode. However, no data can support these properties because no repeated observations have been performed. The mortality, recruitment, and net change in live woody biomass (NPPlw) of a karst evergreen and deciduous broad-leaved mixed forest in Central Guizhou Province, Southwestern China, were studied on the basis of a short-term continuous monitoring (3 years) of a 2 ha plot. The species richness of individuals with a diameter at breast height (DBH) ≥ 1 cm decreased from 66 to 58 during the study period. Eight species disappeared, and no new species appeared. The individual number declined from 16,821 to 15,003 because most species indicated more deaths than recruitments. Trees presented the lowest mortality rate, and shrubs presented the highest recruitment rate among the species. Individual death number decreased with the increase in DBH classes. The estimated aboveground NPPlw was 8.41 t ha−1 year−1. The survivors, recruitments, and deaths contributed 10.88, 0.11, and −2.58 t ha−1 year−1, respectively. Trees (8.37 t ha−1 year−1), rather than shrubs (0.04 t ha−1 year−1) and lianas (−0.004 t ha−1 year−1), were the major contributors. The karst forest presented higher mortality and lower NPPlw than nonkarst forests in subtropical China and in the world.
Leadership style of farmer group leaders

The purpose of this study was to determine the leadership style of the head of the rice farmers group in Tugondeng Village, Herlang District, Bulukumba Regency. The sample of respondents in this study was 45 people. Data collection methods in this study were observations, interviews, and questionnaires. Data analysis methods used in this study were qualitative and quantitative methods. This research was conducted in January 2019 located in Tugondeng Village. The leadership style in Tugondeng Village is 920 (35.0%). This situation shows that the leadership style of the head of the farmer group in Tugondeng Village, Herlang District, Bulukumba Regency applies a democratic leadership style.
Optimising ‘Positive’ Findings from Judgement Bias Tests: A Consideration of Inherent Confounding Factors Associated with Test Design and Biology

The assessment of positive emotional states in animals has been advanced considerably through the use of judgement bias testing. JBT methods have now been reported in a range of species. Generally, these tests show good validity as ascertained through use of corroborating methods of affective state determination. However, published reports of judgement bias task findings can be counter-intuitive and show high inter-individual variability. It is proposed that these outcomes may arise as a result of inherent inter- and intra-individual differences as a result of biology. This review discusses the potential impact of sex and reproductive cycles, social status, genetics, early life experience and personality on judgement bias test outcomes. We also discuss some aspects of test design that may interact with these factors to further confound test interpretation. There is some evidence that a range of biological factors affect judgement bias test outcomes, but in many cases this evidence is limited and needs further characterisation to reproduce the findings and confirm directions of effect. It is our proposition that researchers should consider dedicated study on these factors and their impact on judgement biasing. This is needed to confirm effect and investigate mechanisms. Alternately, consideration and reporting of these factors in JBT studies through incorporation in statistical analyses will provide much needed additional data on their impact. These actions will enhance the validity and practical applicability of the JBT for welfare assessment.
Numerical modelling of twin-screw pumps based on computational fluid dynamics

Increasing demands for high-performance screw pumps in oil and gas as well as other applications require deep understanding of the fluid flow field inside the machine. Important effects on the performance such as dynamic losses, influence of the leakage gaps and presence and extent of cavitation are difficult to observe by experiments. However, it is possible to study such effects using well-validated computational fluid dynamics models. The novel-structured numerical mesh consisting of a single-computational domain for moving screw pump rotors was developed to allow three-dimensional computational fluid dynamics simulation of such machine possible. Based on finite volume method, the instantaneous mass flow rates, rotor torque, local pressure field, velocity field and other performance indicators including the indicated power were predicted. A calculation model for the bearing friction losses was introduced to account for mechanical losses. The geometry of the inlet and outlet passages and piping system are taken into consideration to evaluate their influences on the pressure distribution and shaft power. The paper also shows the influence of rotor clearances on the pump performance. The computational fluid dynamics model was validated by comparing the numerical results with the measured performance obtained in the experimental test rig through the comprehensive experiment performed for a set of discharge pressures and rotational speeds. Validation includes comparison of mass flow rates, shaft power and efficiency under variety of speeds and discharge pressure. It has been found that the predicted results match well with the measurements. The results also showed that the radial clearances have larger influence on the mass flow rate than the interlobe clearance. The correct design of the flow passages within the screw pump plays significant role in minimizing required power consumption. The analysis presented in this paper contributes to better understanding of the working process inside the screw pump and offers a good reference to improve design and optimize such machines in terms of clearance selection, shape of the ports, piping system, etc. In future, this model will be used for analysis of cavitating flows and determining performance of other multiphase screw pumps.
Effect of Substrate on In-flight Particle Characteristics in Suspension Plasma Spraying

Thermal spray technology is a widely used technique in industry in which surfaces of materials are coated by spraying a wide range of metals or ceramics. Considering the growing interest in building nanostructured coatings due to their significant characteristics a new technique called suspension plasma spraying is developed. In this method, a coating is formed by injecting a suspension of nano or sub-micron sized particles into a plasma flame. Obtaining a uniform coating on mechanical parts is one of the industrial challenges in suspension plasma spraying. Through a three dimensional numerical analysis, this study is aimed at providing a better understanding of the effect of substrate position and curvature on in-flight particle temperature, velocity and trajectory. The high temperature and high velocity plasma flow is simulated inside the plasma torch using a uniform volumetric heat source in the energy equation. The suspension of yttria stabilized zirconia (YSZ) particles is used here due to its vast applications in forming thermal barrier coatings. Suspension is molded in this study as a multicomponent droplet while catastrophic breakup regime is considered for simulating the secondary break-up when the suspension interacts with the plasma flow. A two-way coupled Eulerian-Lagrangian approach along with a stochastic discrete model was used to track the particle trajectory. Particle size distribution in the vicinity of the substrate at different standoff distances has been investigated. Then the effect of substrate curvature on in-flight particle characteristics is discussed. The results show that sub-micron particles obtain higher velocity and temperature compared to the larger particles. However, due to the small Stokes number associated with sub-micron particles, they are more sensitive to the change of the gas flow streamlines in the vicinity of the substrate.
Probabilistic Model for Aero-Engines Fleet Condition Monitoring

Since aeronautic transportation is responsible for a rising share of polluting emissions, it is of primary importance to minimize the fuel consumption any time during operations. From this perspective, continuous monitoring of engine performance is essential to implement proper corrective actions and avoid excessive fuel consumption due to engine deterioration. This requires, however, automated systems for diagnostics and decision support, which should be able to handle large amounts of data and ensure reliability in all the multiple conditions the engines of a fleet can be found in. In particular, the proposed solution should be robust to engine-to-engine deviations and different sensors availability scenarios. In this paper, a probabilistic Bayesian network for fault detection and identification is applied to a fleet of engines, simulated by an adaptive performance model. The combination of the performance model and the Bayesian network is also studied and compared to the probabilistic model only. The benefit in the suggested hybrid approach is identified as up to 50% higher accuracy. Sensors unavailability due to manufacturing constraints or sensor faults reduce the accuracy of the physics-based method, whereas the Bayesian model is less affected.
Escaping nonthermal continuum radiation

New observations by the ISEE 1 plasma wave receiver reveal heretofore unreported details of the nonthermal continuum radiation from the earth. In particular, the higher frequency escaping component shows temporal and spectral features which are quite different from those of the lower frequency trapped emission. The higher frequency component is often clearly separated in frequency from the trapped component and high resolution spectrograms show that the escaping radiation consists of numerous narrowband emissions which drift slowly in frequency with time. The higher frequency component also exhibits greater temporal and spatial variability in both amplitude and frequency although the temporal variations are still quite smooth when compared to the more intense and higher frequency auroral kilometric radiation. Evidence is presented which clearly shows a direct connection between intense electrostatic emissions near the upper hybrid frequency and the escaping continuum radiation and strongly suggests the latter electromagnetic emission is generated through mode coupling with the upper hybrid waves. The new ISEE observations of the escaping continuum radiation from the earth strongly suggest a close correspondence with the newly reported narrowband kilometric radiation from Jupiter. Both emissions are relatively narrowband and show slow variations in amplitude with time. In both cases, the narrowband radiation lies above the trapped continuum radiation and below the intense extraordinary mode emissions (auroral kilometric radiation at the earth and decametric radiation at Jupiter). Evidence from both planets suggests the radiation is generated by intense electrostatic waves near the upper hybrid resonance frequency in the vicinity of the plasmapause at the earth and at the outer edge of the Io plasma torus at Jupiter.
Deriving the Two Argument Restriction without Recursion

It is a universal property of argument structure that verbs cannot take more than three arguments –one external and two internal (Hale K, Keyser SJ, On argument structure and the lexical expression of syntactic relations. In: Hale K, Keyser J (eds) The view from Building 20: essays in linguistics in honor of Sylvain Bromberger. MIT, Cambridge, 2002, henceforth H&K); any additional (pseudo)arguments are introduced via (possibly recursive) syntactic or discursive procedures, not lexical. This is the Two (internal) Argument Restriction (TAR), which is part of the basic architecture of natural language. It is argued that a modified version of the theory presented in H&K can account for this restriction. In this proposal, the TAR crucially depends on the lack of recursion in the lexicon (in building argument structures), thereby restricting the possibility of using this formal mechanism to the domain of sentential syntax (building of sentences). Argument structures are thus built in a cyclic and directional way, and without recursion. Abstract It is a universal property of argument structure that verbs cannot take 4 more than three arguments –one external and two internal (Hale K, Keyser SJ, On 5 argument structure and the lexical expression of syntactic relations. In: Hale K, 6 Keyser J (eds) The view from Building 20: essays in linguistics in honor of 7 Sylvain Bromberger. MIT, Cambridge, 2002, henceforth H&K); any additional 8 (pseudo)arguments are introduced via (possibly recursive) syntactic or discursive 9 procedures, not lexical. This is the Two (internal) Argument Restriction (TAR), 10 which is part of the basic architecture of natural language. It is argued that a 11 modiﬁed version of the theory presented in H&K can account for this restriction. 12 In this proposal, the TAR crucially depends on the lack of recursion in the lexicon 13 (in building argument structures), thereby restricting the possibility of using this 14 formal mechanism to the domain of sentential syntax (building of sentences). 15 Argument structures are thus built in a cyclic and directional way, and without 16 recursion.
M ar 2 01 8 On the Ambiguity in Relativistic Tidal Deformability

The LIGO collaboration recently reported the first gravitational-wave constraints on the tidal deformability of neutron stars. I discuss an inherent ambiguity in the notion of relativistic tidal deformability that, while too small to affect the present measurement, may become important in the future. I propose a new way to understand the ambiguity and discuss future prospects for reliably linking observed gravitational waveforms to compact object microphysics. On the Ambiguity in Relativistic Tidal Deformability 2
Responses Of Pre-Fasted Growing Turkeys To Acute Heat Exposure

Nicholas turkeys at the age of 15 to 16 weeks were fasted for 24 hours in a moderate environment and then subjected to acute heat exposures of various dry-bulb and wet-bulb temperatures (T^u, and T^jj). Total feed intake was not influenced by T^^ of 32*' C, 36* C or 40 C (P > 0.10), although differences existed in dynamic feeding profiles. Total heat production rate (THP) varied quadratically with T^^, and respiratory quotient (RQ) decreased linearly with T^u,. The lower RQ values at the higher T^i^ levels may have resulted from reduced feed assimilation. No differences were detected on feed intake, THP, and RQ between the two T^j, levels at each T^^. A THP-based temperature-humidity index, 0J4T^^ + 0.26T^l,, was derived for the turkeys. In addition, T^^ and T^j, had 56% and -44% relative importance on latent heat loss, but -32% and 68% relative importance on sensible heat loss.