Miracle-dz/UniFAR-FTUs huggingface dataset:
Dropout compensation in magnetic tape channels by adaptive equalization and coding

A simple adaptive extended partial response IV (EPR4) equalizer with an adaptive gain controller driven by a threshold detector with relaxed thresholds can be applied effectively on fading tape channels. The equalizer closely approximates the performance of the optimal EPR4 equalizer. Other EPR4 equalizers with certain advantageous features (the EPR4 equalizer with decision feedback and the PW/sub 50/-based EPR4 equalizer) are also studied. The parallel concatenated parity check (PCPC) code with iterative decoding is quite effective in mitigating the dropout effect. The complexity/performance tradeoffs of the PCPC code seem favorable compared to the low-density parity check code or to the turbo code.
Entrainment and mixing of water droplets across a shearless turbulent interface with and without gravitational effects

We describe experiments of the entrainment and mixing of water (sub-Kolmogorov scale) droplets across a turbulent–non-turbulent interface (TNI) as well a turbulent–turbulent interface (TTI) in shearless grid turbulence, over a time scale in which evaporation is insignificant. The flow is produced by means of a splitter plate with an active grid and water sprays on one side and screens or an active grid on the other side. The Taylor microscale Reλ on the turbulent side is 275 and the average dissipation scale Stokes number, Stη ≈ 0.2, and based on the integral scale, Stl ≈ 0.003. By changing the orientation of the grid system, gravitational effects may be excluded or included. We show that in the absence of gravity, for the Stokes number range studied (0.06 ≤ Stη ≤ 1.33), the droplet distribution does not change across the interface. With gravity, the larger drops are selectively mixed and this is more pronounced for the TNI than for the TTI. The particle concentration distribution is an error function for the TTI but departs significantly for the TNI due to the intermittency in the flow. In terms of particle concentration, the entrainment is most efficient for the TTI with gravity. The results are related to droplet entrainment in clouds.
Optimization of intracavity doubled passively Q-switched solid-state lasers

Passively Q-switched lasers can be optimized by the choice of two factors: (1) reflectivity of the output coupler and (2) transmission of an unsaturated absorber. When intracavity frequency doubling is adopted, the nonlinear crystal behaves as a nonlinear output coupler. In this paper, we generalize the optimization theory for intracavity frequency-doubled passively (Q)-switched lasers. By introducing a nonlinear loss term caused by the frequency doubler into the coupled rate equations describing the operation of saturable absorber passively Q-switched lasers, we can express the harmonic pulse characteristics such as peak power, pulse energy, pulsewidth, and a factor describing pulse symmetry. Using the Lagrange multiplier technique to maximize the peak power of the second harmonic for a given pump level, we obtain an additional constraint equation describing the relation of a frequency-doubling factor to a normalized intermediate variable, which can be solved quickly to determine the characteristics of the pulse. The frequency-doubling factor, which is a normalized key parameter, is found to depend not only on the commonly used coefficient of the nonlinear frequency doubler and the emission cross section of the laser medium, but also on the laser cavity optical length. We plot design curves indicating the key parameter and the pulse characteristics via two normalized variables, one representing the pump level, and the other representing the laser emission medium and the absorber medium. Using these curves and expressions, one can design an optimal passively Q-switched intracavity frequency-doubled miniature laser and predict the pulse characteristics without relying on computer calculation.
Neural network‐based adaptive attitude tracking control for flexible spacecraft with unknown high‐frequency gain

Adaptive control design using neural networks (a) is investigated for attitude tracking and vibration stabilization of a flexible spacecraft, which is operated at highly nonlinear dynamic regimes. The spacecraft considered consists of a rigid body and two flexible appendages, and it is assumed that the system parameters are unknown and the truncated model of the spacecraft has finite but arbitrary dimension as well, for the purpose of design. Based on this nonlinear model, the derivation of an adaptive control law using neural networks (NNs) is treated, when the dynamics of unstructured and state‐dependent nonlinear function are completely unknown. A radial basis function network that is used here for synthesizing the controller and adaptive mechanisms is derived for adjusting the parameters of the network and estimating the unknown parameters. In this derivation, the Nussbaum gain technique is also employed to relax the sign assumption for the high‐frequency gain for the neural adaptive control. Moreover, systematic design procedure is developed for the synthesis of adaptive NN tracking control with L2 ‐gain performance. The resulting closed‐loop system is proven to be globally stable by Lyapunov's theory and the effect of the external disturbances and elastic vibrations on the tracking error can be attenuated to the prescribed level by appropriately choosing the design parameters. Numerical simulations are performed to show that attitude tracking control and vibration suppression are accomplished in spite of the presence of disturbance torque/parameter uncertainty. Copyright © 2009 John Wiley & Sons, Ltd.
Regular periodic decompositions for topologically transitive maps

One may often decompose the domain of a topologically transitive map into finitely many regular closed pieces with nowhere dense overlap in such a way that these pieces map into one another in a periodic fashion. We call decompositions of this kind regular periodic decompositions and refer to the number of pieces as the length of the decomposition. If $f$ is topologically transitive but $f^{n}$ is not, then $f$ has a regular periodic decomposition of some length dividing $n$. Although a decomposition of a given length is unique, a map may have many decompositions of different lengths. The set of lengths of decompositions of a given map is an ideal in the lattice of natural numbers ordered by divisibility, which we call the decomposition ideal of $f$. Every ideal in this lattice arises as a decomposition ideal of some map. Decomposition ideals of Cartesian products of transitive maps are discussed and used to develop various examples. Results are obtained concerning the implications of local connectedness for decompositions. We conclude with a comprehensive analysis of the possible decomposition ideals for maps on 1-manifolds.
Diurnal and Seasonal Cycles of Cloud Occurrences, Types, and Radiative Impact over West Africa

AbstractThis study focuses on the occurrence and type of clouds observed in West Africa, a subject that has been neither much documented nor quantified. It takes advantage of data collected above Niamey, Niger, in 2006 with the Atmospheric Radiation Measurement (ARM) Mobile Facility. A survey of cloud characteristics inferred from ground measurements is presented with a focus on their seasonal evolution and diurnal cycle. Four types of clouds are distinguished: high-level clouds, deep convective clouds, shallow convective clouds, and midlevel clouds. A frequent occurrence of the latter clouds located at the top of the Saharan air layer is highlighted. High-level clouds are ubiquitous throughout the period whereas shallow convective clouds are mainly noticeable during the core of the monsoon. The diurnal cycle of each cloud category and its seasonal evolution are investigated. CloudSat and Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) data are used to demonstrate that these f.
On the importance of generating accurate turbulent boundary condition for unsteady simulations

Turbulence is generally characterized by random, chaotic motion and has always been a challenging problem for fluid dynamists. Several methods for generating turbulent boundary conditions for computational fluid dynamics are in use today. One of the methods is by adding random white-noise to the averaged velocity profiles to generate turbulence in the flow field, which can be considered as the simplest and inexpensive method. Recently, another method has been introduced, which is based upon a digital filter to generate turbulent inflow data. This paper presents a comparison of the digital filter-based turbulent inflow data generation technique with three different methods within the framework of the large eddy simulations technique using the fifth- and second-order accurate methods in space and time, respectively. The case for comparison/analysis is a sonic jet of air injected transversely into a supersonic (Mach 1.6) stream of air, for which experimental and classical large eddy simulation data were available. It is demonstrated that the random white-noise-based turbulent inflow data dissipate immediately in the computational domain, giving incorrect velocity and pressure profiles. At the same time, the importance of two-point Exponential correlation used in the digital filter-based technique is demonstrated by scaling the random white-noise with the Reynolds stress tensor and ignoring the correlation. This improved the results compared with pure random white-noise, but still exhibits a high initial dissipation rate because the energy is not distributed over the required range of wavenumbers. It is demonstrated that the digital filter-based turbulent inflow data generation technique provides a reliable, accurate and consistent turbulent boundary layer in the flow field, which is required for the capture of correct flow physics. It is also demonstrated that the computational cost involved in all the methods presented is almost identical.
Block copolymer micelle nanolithography on non-conductive substrates

A new lithographic technique has been developed and applied to cell adhesion studies and electro-optical material development. Attachment of 6 nm Au particles, in periodic and non-periodic pattern, onto non-conductive substrates has been achieved. This was performed via a combination of diblock copolymer self-assembly and electron beam lithographic techniques. To optimize e-beam resolution on non-conductive materials, an additional carbon layer was thread-coated onto the substrates. This carbon coating and the diblock copolymer used in the self-assembly step were simultaneously removed by a final hydrogen plasma treatment to reveal Au nanodot patterns of unprecedented pattern quality. These optically transparent substrates (glass cover slips) were bio-functionalized via the Au-dot patterns to yield a platform for unique cell adhesion studies. The same Au-dot patterning technique was applied to sapphire substrates, which were subsequently employed to nucleate electro-optically active ZnO nanopost growth.
Adsorption Isotherm and Separation Factor for Multicomponent Hydrogen Isotopes in Cryosorption Method for Recovery of Tritium from Blanket Sweep Gas

The effective tritium recovery system should be designed to recover tritium from DT reactor blanket sweep gas in a form easy to transfer to the main fuel cycle. The cryosorption method using a porous adsorbent at the temperature of liquid nitrogen is one of the candidate processes for extracting tritium from hydrogen-swamped helium sweep gas because it has advantages of a large recovery capacity of gaseous tritium and good releasability of recovered tritium to the next process. In order to quantify the performance of the cryosorption method in recovering hydrogen isotopes from hydrogen-swamped helium sweep gas flow, the adsorption capacity and separation factor for multicomponent hydrogen isotope mixtures in helium on molecular sieve 4A (MS4A), molecular sieve 5A (MS5A) and activated carbon at 77.4 K were measured. 8 refs., 3 figs., 2 tabs.
Frictionless multiple impacts in multibody systems. II. Numerical algorithm and simulation results

Part I of this paper develops a framework that is an extension of the Darboux–Keller shock dynamics towards frictionless multiple impacts between bodies composed of rate-independent materials. A numerical algorithm is proposed in this paper, in which the impulsive differential equation is discretized with respect to the primary impulse corresponding to the contact with the highest potential energy, and the integration step size is estimated at the momentum level. This algorithm respects the energetic constraints and avoids the stiff ordinary differential equation problem arising by directly using the compliant model. The well-known example of Newton's cradle, as well as Bernoulli's system, is used to illustrate the developments.
DEVELOPMENT OF NEW EMPIRICAL EQUATIONS FOR ESTIMATION OF DRAG COEFFICIENT, SHAPE DEFORMATION, AND RISING VELOCITY OF GAS BUBBLES OR LIQUID DROPS

Some new correlations are derived to estimate the drag coefficient, the shape deformation, and the rising velocity of particles moving in an infinite liquid medium. The correlations are derived in terms of the dimensionless groups such as Reynolds number (Re), Morton number (Mo), and Weber number (We). The derivations are based on the experimental data or some other correlations given in the literature. A single statement is proposed to estimate the drag coefficient for the spherical solid particles that may be applicable in the range of 0.5 < Re < 105. Similarly, some other equations are also derived to estimate the drag coefficient, the shape deformation, or the rising velocity for gas bubbles or liquid drops. The drag equation is applicable in the range of 0.5 < Re < 100 and 9 × 10−7 ≤ Mo ≤ 7; the shape deformation equation is applicable in the range of 0.5 < Re < 100 and 1.1 × 10−5 ≤ Mo ≤ 7; and the rising velocity equation is applicable in the range of 0.1 < Re < 100 and 9 × 10−7 ≤ Mo ≤ 80. The model predictions are compared with the experimental data and with the other correlations given in the literature. The results indicated that the model predictions are in a good agreement with the literature data.
Schwinger-Dyson equations and gluon bound states of QCD

Nonperturbative techniques in quantum field theory, such as lattice gauge theory, Schwinger- Dyson equations, and applications of the renormalization group, have been successful in describing both the propagator functions and bound states of various theories, most notably those of quarks and hadrons in Quantum Chromodynamics (QCD). The Schwinger-Dyson theoretical framework is presented from basic principles and developed, through examples in a variety of quantum field theories, as a general numerical approach which can yield valuable insight into quantum phenomenology. Explorations include the studies which I have performed to extend bound state theory to the gauge sector of QCD, including the influence of both gluon and ghost fields. This allows for the description of gluon bound states (“glueballs”), which are theoretically viable explanations for previously unidentified resonances in experimental particle searches, and is treated for the first time using the Bethe-Salpeter formalism. This description is sufficiently robust to explore the spectrum of glueballs and provide commentary on the potential for investigation of valence gluon content in meson bound states. Additionally, the first investigation of the full two-loop gluon gap equation is presented and discussed, along with general commentary on the current state of nonperturbative QCD. This computation yields the dressed propagators for quarks, gluons, and ghosts from the coupled set of equations.
Shear banding or not in entangled DNA solutions depending on the level of entanglement

(Received 28 November 2007; final revision received 6 October 2008 Synopsis Entangled DNA solutions are ideal as a model system to examine nonlinear shear flow behavior. Even when the number of entanglements per chain, Z, is higher than 100, the solution is still soft enough with an elastic plateau modulus under 100 Pa and is thus amenable to experimental study by commercial rotational rheometry without ambiguity and uncertainty. We have investigated nonlinear flow behavior of three entangled DNA solutions with Z=24, 60, and 156, respectively, using a combination of particle-tracking velocimetric PTV and conventional rheometric measurements. We explore questions such as a whether shear banding also occurs in moderately entangled solutions, b whether creep results in development of nonlinear velocity profile, c whether shear banding produced in startup shear and creep persists at long times in steady state, and d whether these entangled solutions exhibit homogeneous shear at the upper end of the stress plateau region. We found that the first DNA solution Z=24 only shows transient weakly inhomogeneous shear and steady linear velocity profile. In the more entangled solutions Z=60 and 156, shear banding is observed in startup rate- and stress-controlled shear in the shear thinning regime. Shear homogeneity eventually returns at the upper end of the stress plateau shear
Isolation and Characterization of the First Zobellviridae Family Bacteriophage Infecting Klebsiella pneumoniae

In order to address the upcoming crisis in the treatment of Klebsiella pneumoniae infections, caused by an increasing proportion of resistant isolates, new approaches to antimicrobial therapy must be developed. One approach would be to use (bacterio)phages and/or phage derivatives for therapy. In this study, we present a description of the first K. pneumoniae phage from the Zobellviridae family. The vB_KpnP_Klyazma podovirus, which forms translucent halos around the plaques, was isolated from river water. The phage genome is composed of 82 open reading frames, which are divided into two clusters located on opposite strands. Phylogenetic analysis revealed that the phage belongs to the Zobellviridae family, although its identity with the closest member of this family was not higher than 5%. The bacteriophage demonstrated lytic activity against all (n = 11) K. pneumoniae strains with the KL20 capsule type, but only the host strain was lysed effectively. The receptor-binding protein of the phage was identified as a polysaccharide depolymerase with a pectate lyase domain. The recombinant depolymerase protein showed concentration-dependent activity against all strains with the KL20 capsule type. The ability of a recombinant depolymerase to cleave bacterial capsular polysaccharides regardless of a phage’s ability to successfully infect a particular strain holds promise for the possibility of using depolymerases in antimicrobial therapy, even though they only make bacteria sensitive to environmental factors, rather than killing them directly.
Single-Stage Externalized Locked Plating for Treatment of Unstable Meta-Diaphyseal Tibial Fractures

(1) Background: Unstable meta-diaphyseal tibial fractures represent a heterogeneous group of injuries. Recently, good clinical results have been reported when applying a technique of externalized locked plating in appropriate cases, highlighting its advantage in terms of less additional tissue injury compared with conventional methods of fracture fixation. The aims of this prospective clinical cohort study were, firstly, to investigate the biomechanical and clinical feasibility and, secondly, to evaluate the clinical and functional outcomes of single-stage externalized locked plating for treatment of unstable, proximal (intra- and extra-articular) and distal (extra-articular), meta-diaphyseal tibial fractures. (2) Methods: Patients, who matched the inclusion criteria of sustaining a high-energy unstable meta-diaphyseal tibial fracture, were identified prospectively for single-stage externalized locked plating at a single trauma hospital in the period from April 2013 to December 2022. (3) Results: Eighteen patients were included in the study. Average follow-up was 21.4 ± 12.3 months, with 94% of the fractures healing without complications. The healing time was 21.1 ± 4.6 weeks, being significantly shorter for patients with proximal extra- versus intra-articular meta-diaphyseal tibial fractures, p = 0.04. Good and excellent functional outcomes in terms of HSS and AOFAS scores, and knee and ankle joints range of motion were observed among all patients, with no registered implant breakage, deep infection, and non-union. (4) Conclusions: Single-stage externalized locked plating of unstable meta-diaphyseal tibial fractures provides adequate stability of fixation with promising clinical results and represents an attractive alternative to the conventional methods of external fixation when inclusion criteria and rehabilitation protocol are strictly followed. Further experimental studies and randomized multicentric clinical trials with larger series of patients are necessary to pave the way of its use in clinical practice.
Semi-Fredholm solvability and asymptotic expansions of singular solutions for Protter problems

We study four-dimensional boundary value problems for the nonhomogeneous wave equation, which are analogues of Darboux problems on the plane. It is known that the unique generalized solution may have a strong power-type singularity at only one point. This singularity is isolated at the vertex O of the boundary light characteristic cone and does not propagate along the cone. We find asymptotic expansion of the generalized solutions in negative powers of the distance to O. Necessary and sufficient conditions for existence of bounded solutions are derived and additionally some a priori estimates for the singular solutions are given.
Ellipsoidal model for droplet deformation in emulsions

An ellipsoidal model for droplet deformation in mixtures of Newtonian fluids is proposed. The model makes a bridge between the phenomenological description of the ellipsoidal deformation of the droplet [Eshelby (1957); Maffetonne and Minale (1998); Jackson and Tucker (JT model) (2003); Wetzel and Tucker (WT model) (2001)] and the interfacial velocity calculation between two Newtonian liquids. The bridging was obtained by the use of the general boundary integral formalism. The velocity at the interface was decomposed into a flow dominated term and an interfacial term. The flow term is the same as in JT and WT models and arises from Eshelby’s theory, while the interfacial term was calculated by assuming a linear, uniform velocity gradient tensor over the entire surface of the droplet. The model for droplet deformation is applicable to mixtures of two Newtonian liquids with arbitrary viscosity ratio and nonzero interfacial tension. The predictions of the present model in terms of shape evolution of the droplet agree well with many experiments and numerical simulations including transient deformation for small and large capillary numbers, transient shear widening for small viscosity ratio and large capillary numbers, and steady shear deformation. The rheology of dilute emulsions based on the morphological predictions by the present model was calculated according to Batchelor’s formalism (1970). The predicted rheological material functions agree reasonably well with the experimental data. The limitations of the present model are also discussed.