A call for enhanced data-driven insights into wind energy flow physics

With the increased availability of experimental measurements aiming at probing wind resources and wind turbine operations,machine learning(ML)models are poised to advance our understanding of the physics underpinning the interaction between the atmospheric boundary layer and wind turbine arrays,the generated wakes and their interactions,and wind energy harvesting.However,the majority of the existing ML models for predicting wind turbine wakes merely recreate Computational fluid dynamics(CFD)simulated data with analogous accuracy but reduced computational costs,thus providing surrogate models rather than enhanced data-enabled physics insights.Although ML-based surrogate models are useful to overcome current limitations associated with the high computational costs of CFD models,using ML to unveil processes from experimental data or enhance modeling capabilities is deemed a potential research direction to pursue.In this letter,we discuss recent achievements in the realm of ML modeling of wind turbine wakes and operations,along with new promising research strategies.

Period–Luminosity Relationship forδScuti Stars Revisited

The Gaia DR3 parallax approach was used to estimate the absolute parameters of 2375δScuti stars from the ASAS catalog.The selected stars have a variety of observational characteristics,with a higher than 80%probability of beingδScuti stars.We have displayed all the stars in the Hertzsprung-Russell diagram along with theδScuti instability strip,the Zero Age Main Sequence and the Terminal Age Main Sequence.Then,we determined which fundamental and overtone modes each star belongs to using pulsation constant(Q)calculations.In addition,we evaluated the parameters in the Q calculation equation using three machine learning methods,which showed that surface gravity and temperature have the greatest effect on its calculation.The Period-Luminosity(P-L)relationship of theδScuti stars was also revisited.Eventually,using least squares linear regression,we made four linear fits for fundamental and overtone modes and updated their relationships.

Impacts of Land Use and Cover Change on Land Surface Temperature in the Zhujiang Delta

Remote sensing and geographic information systems (GIS) technologies were used to detect land use/cover changes (LUCC) and to assess their impacts on land surface temperature (LST) in the Zhujiang Delta. Multi-temporal Landsat TM and Landsat ETM+ data were employed to identify patterns of LUCC as well as to quantify urban expansion and the associated decrease of vegetation cover. The thermal infrared bands of the data were used to retrieve LST. The results revealed a strong and uneven urban growth,which caused LST to raise 4.56℃in the newly urbanized part of the study area. Overall, remote sensing and GIS technologies were effective approaches for monitoring and analyzing urban growth patterns and evaluating their impacts on LST.

Multidirectional 3D printed functionally graded modular joint actuated by TCPFL muscles for soft robots

Highly deformable bodies are essential for numerous types of applications in all sorts of environments. Joint-like structures comprising a ball and socket joint have many degrees of freedom that allow mobility of many biomimetic structures. Recently, soft robots are favored over rigid structures for their highly compliant material, high-deformation properties at low forces, and ability to operate in di fficult environments. However, it is still challenging to fabricate complex designs that satisfy application constraints due to the combined e ffects of material properties, actuation method, and structural geometry on the performance of the soft robot. Therefore, a combination of a rigid joint and a soft body can help achieve modular robots with fully functional body morphology. Yet, the fabrication of soft parts requires extensive molding for complex shapes, which comprises several processes and can be time-consuming. In addition, molded connections between extremely soft materials and hard materials can be critical failing points. In this paper, we present a functionally graded 3D-printed joint-like structure actuated by novel contractile actuators. Functionally graded materials (FGMs) via 3D printing allow for extensive material property enhancement and control which warrant tunable functionalities of the system. The 3D-printed structure is made of 3 rigid ball and socket joints connected in series and actuated by integrating twisted and coiled polymer fishing line ( TCPFL) actuators, which are con fined in the FGM accordion-shaped channels. The implementation of the untethered T CPFL actuation system can be highly bene ficial for deployment in environments that require low vibrations and silent actuation. The fishing line TCP actuators produce an actuation strain up to 40% and bend the joint up to 40° in any direction. The T CPFL can be actuated individually or as a group to control the bending trajectory of the modular joint, which is bene ficial when deployed in areas that contain small crevices. Obtaining complex modes of bending, the FGM multidirectional joint demonstrated a great potential to achieve di fferent functionalities such as crawling, rolling, swimming, or underwater exploration.

High-throughput identification of one-dimensional atomic wires and first principles calculations of their electronic states

Low dimensional materials are suitable candidates applying in next-generation high-performance electronic,optoelectronic,and energy storage devices because of their uniquely physical and chemical properties.In particular,one-dimensional(1D)atomic wires(AWs)exfoliating from 1D van der Waals(vdW)bulks are more promising in next generation nanometer(nm)even sub-nm device applications owing to their width of few-atoms scale and free dandling bonds states.Although several 1D AWs have been experimentally prepared,few 1D AW candidates could be practically applied in devices owing to lack of enough suitable 1D AWs.Herein,367 kinds of 1D AWs have been screened and the corresponding computational database including structures,electronic structures,magnetic states,and stabilities of these 1D AWs has been organized and established.Among these systems,unary and binary 1D AWs with relatively small exfoliation energy are thermodynamically stable and theoretically feasible to be exfoliated.More significantly,rich quantum states emerge,such as 1D semiconductors,1D metals,1D semimetals,and 1D magnetism.This database will offer an ideal platform to further explore exotic quantum states and exploit practical device applications using 1D materials.The database are openly available at http://www.dx.doi.org/10.11922/sciencedb.j00113.00004.

Impact Estimation and Filtering of Disturbances in FG5 Absolute Gravimeter Observations

Instrumental and environmental disturbances do affect FG5 absolute gravimeter observations and the estimated gravity values, sometimes to the degree that entire measurement campaigns are discarded. We propose a method which moves towards the re-assessment of previously discarded observations. Once an estimate of the frequency and amplitude of a disturbance in a FG5 data set exists, the proposed method can estimate its impact on the estimated gravity value. This is performed through a Gaussian Bell Summation approach of the functional relationship between disturbance frequency and standard deviation of gravity. The filtering of the identified disturbance is realized through a modification of the functional model of the equation of motion in the least squares adjustment of FG5 observations. The results reveal that the Gaussian Bell Summation approximates the frequency—gravity impact relationship sufficiently well with negligible uncertainties, while the accuracy of the detected disturbance frequency defines a limiting factor for the gravity impact estimation. A realistic disturbance of 15 Hz with an amplitude of 1.5 nm had an impact of ≈48 [μGal] on the gravity estimate. The proposed filter approach reduced the impact to ≈12 [μGal], with the remaining effect being almost entirely associated to the uncertainty in disturbance frequency detection.

Reduced Order Machine Learning Finite Element Methods:Concept,Implementation,and Future Applications Dedicated to Professor Karl Stark Pister for his 95th birthday

This paper presents the concept of reduced order machine learning finite element(FE)method.In particular,we propose an example of such method,the proper generalized decomposition(PGD)reduced hierarchical deeplearning neural networks(HiDeNN),called HiDeNN-PGD.We described first the HiDeNN interface seamlessly with the current commercial and open source FE codes.The proposed reduced order method can reduce significantly the degrees of freedom for machine learning and physics based modeling and is able to deal with high dimensional problems.This method is found more accurate than conventional finite element methods with a small portion of degrees of freedom.Different potential applications of the method,including topology optimization,multi-scale and multi-physics material modeling,and additive manufacturing,will be discussed in the paper.

The influence of marital status on the social dysfunction of schizophrenia patients in community

Objective:Estimate predictive associations of marital status with social dysfunction in schizophrenia patients.Methods:817 schizophrenia patients lived in the community of Dongguan,Guangdong province,China,were investigated with the Social Disability Screening Schedule(SDSS)during a three-month period(1.2010e3.2010).The demographic data were harvested.The c2 test,t test,and fisher's exact were used for comparisons between groups,as appropriate.Multinomial logistic regression(MLR)was used to analyze the predictive associations of demographic variables to the grading of social dysfunctions.Results:The study group consisted of male and female patients aged 16e59 years,407 females,and 410 males with the mean age(40.7±9.5)years.Analysis of the data revealed significant differences in course of disease and marital status among patients(with and without dysfunction).The married patient made a significant difference with divorced/widowed patient in mildlyemoderately social dysfunction.There was a significant difference in married and never-married patient with mildly and profoundly social dysfunction.Significant differences were noticed in the self care and occupational roles of the married patient with that of the never-married.Conclusion:This study confirmed that bad marital status is associated with higher odds of social dysfunction among patients with schizophrenia living in the community.These effects should be included in considerations of public health investments in preventing and treating mental disorders.

Emerging properties of non-crystalline phases of graphene and boron nitride based materials

We review recent developments on the synthesis and properties of two-dimensional materials which, although being mainly of an sp^(2) bonding character, exhibit highly disordered, non-uniform and structurally random morphologies. The emergence of such class of amorphous materials, including amorphous graphene and boron nitride, have shown superior properties compared to their crystalline counterparts when used as interfacial films. In this paper we discuss their structural,vibrational and electronic properties and present a perspective of their use for electronic applications.

Materials Design on the Origin of Gap States in a High-κ/GaAs Interface

Given the demand for constantly scaling microelectronic devices to ever smaller dimensions, a SiO_2 gate dielectric was substituted with a higher dielectric-constant material, Hf(Zr)O_2, in order to minimize current leakage through dielectric thin film. However, upon interfacing with high dielectric constant(high-κ) dielectrics, the electron mobility in the conventional Si channel degrades due to Coulomb scattering, surface-roughness scattering, remotephonon scattering, and dielectric-charge trapping. III-V and Ge are two promising candidates with superior mobility over Si. Nevertheless, Hf(Zr)O_2/III-V(Ge) has much more complicated interface bonding than Si-based interfaces. Successful fabrication of a high-quality device critically depends on understanding and engineering the bonding conflgurations at Hf(Zr)O_2/III-V(Ge) interfaces for the optimal design of device interfaces. Thus, an accurate atomic insight into the interface bonding and mechanism of interface gap states formation becomes essential. Here, we utilize firstprinciple calculations to investigate the interface between HfO_2 and Ga As. Our study shows that As—As dimer bonding, Ga partial oxidation(between 3+ and 1+) and Ga— dangling bonds constitute the major contributions to gap states. These findings provide insightful guidance for optimum interface passivation.

Surface-ligand effect on radiosensitization of ultrasmall luminescent gold nanoparticles

Gold nanoparticles(AuNPs)could serve as pot ential radiother apy sensitizers because of their exceptional biocompatibility and high.Z material nature;however,since in vitro and in vivo behaviors of AuNPs are determined not only by their particle size but also by their surface chemistries,whether surface ligands can affect their radiosensitization has seldom been investi-gated in the radiosensitization of AuNPs.By conducting head-to-head comparison on radio-sensitization of two kinds of ultrasmall(~2 nm)near-infrared(NIR)emitting AuNPs that are coated with zwitterionic glutathione and neutr al polyethylene glyol(PEG)ligands,respectively,we found that zwitterionic glut athione coated AuNPs(GS-AuNPs)can reduce survival rates of MCF-7 cells under irr adiation of clinically used megavoltage photon beam at low dosage of~2.25 Gy.On the other hand,PEG-AuNPs can serve as a radiation-protecting agent and enabled MCF-7 cells more resistant to the irradiation,clearly indicating the key role of surface cheistry in radiosensitization of AuNPs.More detailed studies suggested that such difference was inde-pendent of cellular uptake and its eficiency,but might be related to the ligand-induced difference in photoelectron generation and/or inter actions between AuNPs and X-ray triggered reactive oxygen species(ROS).

Early Cretaceous subduction initiation beneath southern Tibet caused the northward flight of India

Collision between the Indian and Eurasian plates formed the ~2500 km long Yarlung Zangbo Suture Zone and produced the Himalaya mountains and Tibetan plateau.Here we offer a new explanation for tectonic events leading to this collision:that the northward flight of India was caused by an Early Cretaceous episode of subduction initiation on the southern margin of Tibet.Compiled data for ophiolites along the Yarlung Zangbo Suture Zone show restricted ages between 120 Ma and 130 Ma,and their supra-subduction zone affinities are best explained by seafloor spreading in what became the forearc of a north-dipping subduction zone on the southern margin of Tibet.The subsequent evolution of this new subduction zone is revealed by integrating data for arcrelated igneous rocks of the Lhasa terrane and Xigaze forearc basin deposits.Strong slab pull from this new subduction zone triggered the rifting of India from East Gondwana in Early Cretaceous time and pulled it northward to collide with Tibet in Early Paleogene time.

Size-refinement enhanced flexibility and electrochemical performance of MXene electrodes for flexible waterproof supercapacitors

Increasing mechanical flexibility without sacrificing electrochemical performance of the electrode material is highly desired in the design of flexible electrochemical energy storage devices.In metal-related materials science,decreasing the grain size introduces more grain boundaries;this stops dislocations and crack propagation under deformation,and results in increased strength and toughness.However,such a size refinement effect has not been considered in the mechanical properties,particle stacking,wetting,and electrochemical performances of flexible supercapacitor electrodes.In this paper,MXene was used as an electrode material to study the size refinement effect of flexible supercapacitors.Size refinement improved the strength and toughness of the MXene electrodes,and this resulted in increased flexibility.Finite elemental analysis provided a theoretical understanding of size refinement-increased flexibility.Moreover,the size refinement also improved the specific surface area,electric conductance,ion transportation,and water wetting properties of the electrode,and the size refinement provided highly increased energy density and power density of the MXene supercapacitors.A highly flexible,water-proof supercapacitor was fabricated using size-refined MXene.The current study provides a new viewpoint for designing tough and flexible energy storage electrodes.The size refinement effect may also be applicable for metal ion batteries and electronic and photo devices composed of MXene and other nanoparticles.

On the Operation of CMOS Active-Cascode Gain Stage

An s-domain analysis of the full dynamics of the pole-zero pair (frequency doublet) associated with the broadly used CMOS active-cascode gain-enhancement technique is presented. Quantitative results show that three scenarios can arise for the settling behavior of a closed-loop active-cascode operational amplifier depending on the relative locations of the unity-gain frequencies of the auxiliary and the main amplifiers. The analysis also reveals that, although theoretically possible, it is practically difficult to achieve an exact pole-zero cancellation. The analytical results presented here provide theoretical guidelines to the design of CMOS operational amplifiers using this technique.

Change-Point Analysis of Survival Data with Application in Clinical Trials

Effects of many medical procedures appear after a time lag, when a significant change occurs in subjects’ failure rate. This paper focuses on the detection and estimation of such changes which is important for the evaluation and comparison of treatments and prediction of their effects. Unlike the classical change-point model, measurements may still be identically distributed, and the change point is a parameter of their common survival function. Some of the classical change-point detection techniques can still be used but the results are different. Contrary to the classical model, the maximum likelihood estimator of a change point appears consistent, even in presence of nuisance parameters. However, a more efficient procedure can be derived from Kaplan-Meier estimation of the survival function followed by the least-squares estimation of the change point. Strong consistency of these estimation schemes is proved. The finite-sample properties are examined by a Monte Carlo study. Proposed methods are applied to a recent clinical trial of the treatment program for strong drug dependence.

New Horizon in stabilization of single atoms on metal-oxide supports for CO_(2) reduction

Elecrochemical CO_(2) reduction is a promising route to convert CO_(2) into the value added chemicals,and to control the increasing accumulation of 002 in the atmosphere.The CO_(2) molecule is stable and chemically inert,so a highly efficient electrocatalyst is required for CO_(2) reduction.The single atoms with metal oxdde support is a new fronder in CO_(2) reduction.The supported single atoms contain disperse isolated atoms with an appropriate support maxcimize the atom efficiency of metals for boosting the catalytc perfomance.In this review,we had discussed state-of-the-art research on the synthestis of single atoms supported on the metal oxdde for boosting catalytic activity for CO_(2) reduction and special emphasis is placed on the influence of single atoms supported on metal oxdde on the CO_(2) reduction.Futhermore,we had discussed the challenges,and opportunities for paving the development of single atoms with metal support and their application in ecrocatalytic CO_(2) reduction.

The Neighborhood Scale Variability of Airborne Particulates

Airborne particulates play a central role in both the earth’s radiation balance and as a trigger for a wide range of health impacts. Air quality monitors are placed in networks across many cities glob-ally. Typically these provide at best a few recording locations per city. However, large spatial var-iability occurs on the neighborhood scale. This study sets out to comprehensively characterize a full size distribution from 0.25 - 32 μm of airborne particulates on a fine spatial scale (meters). The data are gathered on a near daily basis over the month of May, 2014 in a 100 km2 area encompassing parts of Richardson, and Garland, TX. Wind direction was determined to be the dominant factor in classifying the data. The highest mean PM2.5 concentration was 14.1 ± 5.7 μg·m-3 corresponding to periods when the wind was out of the south. The lowest PM2.5 concentrations were observed after several consecutive days of rainfall. The rainfall was found to not only “cleanse” the air, leaving a mean PM2.5 concentration as low as 3.0 ± 0.5 μg·m-3, but also leave the region with a more uniform PM2.5 concentration. Variograms were used to determine an appropriate spatial scale for future sensor placement to provide measurements on a neighborhood scale and found that the spatial scales varied, depending on the synoptic weather pattern, from 0.8 km to 5.2 km, with a typical length scale of 1.6 km.

A Comparative Study of Amplitude and Timing Estimation in Experimental Particle Physics using Monte Carlo Simulation

Optimal detection of liquid ionization calorimeter signal in experimental particle physics is considered. A few linear and nonlinear approaches for amplitude and arrival time estimation based on the χ2 function are compared in simulation considering the noise sample correlation introduced by the analog pulse shaper. The estimation bias of the first-order approximation, a.k.a linear optimal filtering, is studied and contrasted to those of the second-order as well as the exhaustive search. A gradient-descent technique is presented as an alternative to the exhaustive search with significantly reduced search time and computation complexity. Results from various pulse shapers including the CR-RC2, CR-RC3, and CR2-RC2 are also compared.

Graphene Bridge Heterostructure Devices for Negative Differential Transconductance Circuit Applications

Two-dimensional van der Waals(2D vdW)material-based heterostructure devices have been widely studied for high-end electronic applications owing to their heterojunction properties.In this study,we demonstrate graphene(Gr)-bridge heterostructure devices consisting of laterally series-connected ambipolar semiconductor/Gr-bridge/n-type molybdenum disulfide as a channel material for field-effect transistors(FET).Unlike conventional FET operation,our Gr-bridge devices exhibit nonclassical transfer characteristics(humped transfer curve),thus possessing a negative differential transconductance.These phenomena are interpreted as the operating behavior in two series-connected FETs,and they result from the gate-tunable contact capacity of the Gr-bridge layer.Multi-value logic inverters and frequency tripler circuits are successfully demonstrated using ambipolar semiconductors with narrow-and wide-bandgap materials as more advanced circuit applications based on non-classical transfer characteristics.Thus,we believe that our innovative and straightforward device structure engineering will be a promising technique for future multi-functional circuit applications of 2D nanoelectronics.