Miracle-dz/UniFAR-FTUs huggingface dataset:
Shaping effects on aerodynamics of long-span cable-supported bridge deck by Unsteady RANS

Cable-supported bridge is one of the most popular structural forms adopted for long-span bridges. The applications of cable-supported bridge are increasing with the growing number of long-span bridges due to their aesthetic view and wide navigation facility. The decks of the cable-supported bridges are hanged only by the cables to span over long distance without any intermediate support. As a result, flexibility becomes an inherent property of the cable-supported bridge decks increasing the importance of aerodynamic behavior. The shape of the bridge deck plays an important role and aerodynamic performance can be improved by shaping the bridge deck appropriately without requiring any post-construction structural or aerodynamic counter-measures. There are a number of important shaping parameters for conventional bridge decks. Their influences on aerodynamics as well as response should be well understood for shaping the bridge deck efficiently and facilitating the bridge deck design procedure. In this context, the present study examined the influence of various important shaping parameters on aerodynamic responses of single box bridge deck by employing unsteady RANS simulation. Detailed verification and validation studies were carried out for various bluff bodies and bridge sections to check the performance of two-dimensional unsteady RANS. The main parametric study was devoted for single-box bridge deck with and without fairing due to their frequent application for long-span bridges. A large number of practical bridge decks were surveyed for obtaining general idea about the shaping parameters and their range in practical bridges. Important shaping parameters such as top plate slope (ζT), bottom plate slope (ζB), side ratio (R) and width ratio (W) were considered as a main parameters of interest. Further, practical issues like, Reynolds number (ReB) effects, influence of handrail type, effects of curb and inspection rail on aerodynamic response and flow fields were also researched. Both for bridge deck with and without fairing, the influence of various shaping parameters on static force coefficients were investigated. It was found that the response altered significantly due to variation of shaping parameters and showed minimal value for particular combination of shaping parameters. By exploiting pressure, velocity and vorticity distribution, obtained steady-state
Robot programming by human demonstration

Robots can be programmed to perform different tasks, however, often the difficulty of the programming process limits more widespread use of robotic technology and discourages short term applications. To facilitate the use of robotics an intuitive method of programming is developed, Programming by Human Demonstration. The programmer demonstrates how the task is performed using a teaching gripper that measures the human's forces and positions. A robot program is generated from the demonstration data without using a model of the task geometry. A direct approach to generating a robot program would be to simply duplicate the demonstrated trajectory. However, direct duplication may not succeed if there is variation in the environment. Furthermore, the human trajectory may contain unnecessary motion that would result in an unsatisfactory robot trajectory. To identify a manipulation strategy, multiple demonstrations of the task are performed and comparisons between demonstrations are used to distinguish between human adaptation and inconsistency. Human inconsistency is not interpreted as noise that should be eliminated from the analysis, but provides information about the accuracy requirements of the task for both position and force trajectories. Adaptation is identified by human motion that corresponds to detectable variations in the environment, and is incorporated into the robot program. The analysis is applied to obstacle avoidance and simple assembly tasks consisting of 3D translation. A robot program is generated that can successfully perform the task provided that variations in the environment are not larger than that encountered during the demonstrations. A robot compliance controller is specified that will adapt to workpiece misalignment, and limit robot errors to the accuracy requirements defined by the demonstrator's inconsistency. In addition, the task is segmented into subtasks, and subtask termination conditions are identified that enable the robot to switch from one subtask to the next. Robot success is guaranteed by ensuring that the position accuracy is as high enough to avoid obstacles and reach the desired target position, the direction of robot force maintains the desired contact with the workpiece surfaces, and the magnitude of the robot force is less than the maximum demonstrated force to avoid damage to the parts. Thesis Supervisor: Professor Harry West Title: Associate Professor of Mechanical Engineering
Tuning of the Magnetocaloric Properties of Mn5Ge3 Compound by Chemical Modification

The rare earth-free Mn5Ge3 compound shows magnetocaloric properties similar to those of pure Gd; therefore, it is a good candidate for magnetic refrigeration technology. In this work, we investigate the influence of chemical substitution on the crystal structure and the magnetic, thermodynamic, and magnetocaloric properties of a polycrystalline Mn5Ge3 compound prepared by induction melting. For this purpose, we replaced 5% of the Mn with Cr or Co and 5% of the Ge with B or Al. The additional chemical elements were shown not to change the crystal structure of the parent compound (space group P63/mcm, No. 193). In the case of the magnetic properties, all samples remained ferromagnetic with the ordering temperature (TC) lower than for the original compound (TC = 295(1) K). The exception was the sample with B, where we observed an increase in TC by 3 K. The maximum value of the magnetic entropy change, |∆Sm|MAX (for a magnetic field change of 5 T), decreased from 7.1(1) for Mn5Ge3 to 6.2(1), 6.8(1), 4.8(1), and 5.8(1) J kg−1 K−1 for the alloys with B, Al, Cr, and Co, respectively. The adiabatic temperature change (∆Tad) (for a magnetic field change of 1 T) was determined from the specific heat measurements and was equal to 1.1(1), 1.2(1), 1.2(1), 0.8(1), and 0.8(1) K for Mn5Ge3, Mn5Ge2.85B0. 15, Mn5Ge2.85Al0. 15, Mn4.75Cr0. 25Ge3, and Mn4.75Co0. 25Ge3, respectively. The obtained data were compared with those from the literature. It was found that the substitution allowed for tuning of the ordering temperature in a wide temperature range. At the same time, the reduction in the magnetocaloric parameters’ values was relatively small. Therefore, the produced Mn5Ge3-based alloys allow for the expansion of the operation temperature range of the parent compound as a magnetocaloric material.
Quantification of Seasonal and Interannual Variations of the Tibetan Plateau Surface Thermodynamic Forcing Based on the Potential Vorticity

In this study, a new index based on the potential vorticity (PV) framework is proposed for the quantification of the Tibetan Plateau (TP) surface thermodynamic and dynamic forcing. The results show that the derived TP surface PV (SPV) includes the topographical effect, near‐surface absolute vorticity, and land–air potential temperature differences. The climatological annual cycle of the SPV suggests that the TP transitions from a cooling to a heating source in April. The SPV reaches a maximum from June to August, which is consistent with the evolution of the Asian summer monsoon precipitation. Further analysis suggests that the intensified SPV in the boreal summer results in a low‐level cyclonic circulation anomaly associated with increased precipitation over the southeastern slope of the TP and South China and decreased precipitation over the Indian Ocean. In winter, the intensified SPV is associated with local cold air and divergence at the TP surface.
Local cultural context as a moderator of the impact of childcare on maternal employment: Evidence from a natural experiment

In spite of increasing levels of female employment, having a child below school age often goes along with a substantial decrease in employment engagement for women. Consequently, previous family policy research suggests that increasing childcare availability might be a promising tool to facilitate maternal employment as it increases the economic incentive to take up work. Another line of reasoning highlights that cultural attitudes towards maternal employment are equally important in shaping the employment decisions of mothers. In this article, we combine insights of both approaches and argue that culture, in addition to its direct effect on maternal employment, moderates the impact of childcare policies. In particular, we argue that the positive effect of childcare may be weaker in more conservative cultural contexts. To assess this question empirically, we exploit the implementation of a centralised childcare reform in Poland as a natural experiment by means of a regression discontinuity design. Relying on individual-level data on employment and regional-level information on the influence of conservatism in a certain region, we run multilevel regressions with cross-level interaction terms to estimate the effect of the reform depending on the local cultural context. Consistent with our theoretical expectations, the impact of the reform is rather strong in less conservative areas but fades away in increasingly conservative contexts. Supplementary analyses reveal that the effect also differs with regard to household composition, with smaller families displaying larger gains in maternal employment. These findings confirm that conservative cultural attitudes appear to suppress the positive effect of increasing childcare availability.
Pancharatnam-Berry phase optical elements for VR displays

Virtual reality (VR) systems bring fantastic immersive experiences to users in multiple fields. However, the performance of VR displays is still troubled by several factors, including inadequate resolution, noticeable chromatic aberration, and low optical efficiency. Pancharatnam-Berry phase optical element (PBOE) exhibits several advantages, such as high efficiency, simple fabrication process, compact, and lightweight, which is an excellent candidate for VR systems. We have demonstrated that by using three kinds of PBOEs, the above-mentioned problems can be solved satisfactorily. The first PBOE is PB grating/deflector (PBD), which can deflect the left-handed and the right-handed circularly polarized beams to two opposite directions. Therefore, if we insert a PBD to the VR system and carefully design the deflection angle, it can optically separate each display pixel into two virtual pixels and superimpose them to obtain a higher pixel density. In this way, the pixel per inch (PPI) of the original display can be doubled. The second PBOE is PB lens (PBL). As one kind of diffractive optical lenses, it has an opposite chromatic dispersion to that of a refractive lens. When a PBL with an appropriate focal length is hybridized with a refractive Fresnel lens, the system’s chromatic aberration can be significantly reduced. The third PBOE is multi-domain PB lens. The effective focal length of each domain can be customized independently. This multi-domain PBL can function as a diffractive deflection film in the VR system. If such a diffractive deflection film is cooperated with a directional backlight, the etendue wasting can be reduced prominently, and more than doubled optical efficiency can be achieved in both Fresnel and “Pancake” VR systems. These ultrathin PBOEs will find promising applications in future VR systems
Multicontact Motion Retargeting Using Whole-Body Optimization of Full Kinematics and Sequential Force Equilibrium

This article presents a multicontact motion adaptation framework that enables teleoperation of high degree-of-freedom robots, such as quadrupeds and humanoids, for loco-manipulation tasks in multicontact settings. Our proposed algorithms optimize whole-body configurations and formulate the retargeting of multicontact motions as sequential quadratic programming, which is robust and stable near the edges of feasibility constraints. Our framework allows real-time operation of the robot and reduces cognitive load for the operator because infeasible commands are automatically adapted into physically stable and viable motions on the robot. The results in simulations with full dynamics demonstrated the effectiveness of teleoperating different legged robots interactively and generating rich multicontact movements. We evaluated the computational efficiency of the proposed algorithms, and further validated and analyzed multicontact loco-manipulation tasks on humanoid and quadruped robots by reaching, active pushing, and various traversal on uneven terrains.
Agricultural Product Sales Prediction of ICM Neural Network Improvement by Sparse Autoencoder

With the rapid development of agricultural product sales data, the traditional prediction model cannot meet the processing needs. Based on deep learning theory, an improved ICM agricultural product sales prediction model using the softmax classifier is proposed. Introducing the sparse autoencoder in ICM can reduce feature loss. The features also can be extracted. In addition, using the pretreatment mode based on fuzzy membership theory, we can obtain the fuzzy correspondence of considerations and grades of agricultural product sales. At the same time, the precision of prediction for the model is further optimized. It can be seen that the agricultural product sales prediction model based on improved ICM can realize the real-time prediction of agricultural product sales. The maximum classification accuracy of the model can reach 80.98%, which means that it has certain practical application value.
Population Differences and Host Species Predict Variation in the Diversity of Host-Associated Microbes in Hydra

Most animals co-exist with diverse host-associated microbial organisms that often form complex communities varying between individuals, habitats, species and higher taxonomic levels. Factors driving variation in the diversity of host-associated microbes are complex and still poorly understood. Here, we describe the bacterial composition of field-collected Hydra, a freshwater cnidarian that forms stable associations with microbial species in the laboratory and displays complex interactions with components of the microbiota. We sampled Hydra polyps from 21 Central European water bodies and identified bacterial taxa through 16S rRNA sequencing. We asked whether diversity and taxonomic composition of host-associated bacteria depends on sampling location, habitat type, host species or host reproductive mode (sexual vs. asexual). Bacterial diversity was most strongly explained by sampling location, suggesting that the source environment plays an important role in the assembly of bacterial communities associated with Hydra polyps. We also found significant differences between host species in their bacterial composition that partly mirrored variations observed in lab strains. Furthermore, we detected a minor effect of host reproductive mode on bacterial diversity. Overall, our results suggest that extrinsic (habitat identity) factors predict the diversity of host-associated bacterial communities more strongly than intrinsic (species identity) factors, however, only a combination of both factors determines microbiota composition in Hydra.
Block Kinematics in North China From GPS Measurements

The North China Craton (NCC) is an important tectonic element in China, which is characterized by intense seismic activity and complex tectonic setting. Thus quantifying its deformation is essential for studying the tectonic processes and deformation mechanisms in this region. Here we use a combination of dense GPS data sets to analyze the crustal movement and present updated estimates of fault motions based on elastic block models. We uncover spatial variations in deformation patterns, indicating that different mechanisms may dominate the tectonic processes for different parts of the NCC. In the western part, the rifts around the Ordos block manifest strike‐slip and extensional deformation, and the strike‐slip motion is more significant than the extensional component; whereas in the east, the Tanlu fault experiences right‐lateral and shortening slips, consistent with the features from historical seismic activity and regional tectonics. Our analysis indicates that the deformation in the eastern NCC is principally influenced by the Pacific subduction, whereas the deformation in the western NCC is mainly related to the India‐Eurasia collision. Moreover, our estimate of motion along the Tanlu fault supports a relatively long seismic interval of ∼10 ka, comparable to those inferred from recent paleoseismic research on this fault and other slow‐slip faults in the NCC. Our study indicates that the faults in the NCC even with very slow motions may still have the potential to produce strong earthquakes. Thus seismic risks across these slow‐slip faults cannot be ignored and should not be determined solely based on the rate of fault motions.
A Simulation Study of the Workspace and Dexterity of a Stewart Platform Based Machine Tool

A machine tool based on a Stewart platform structure has many inherent advantages. These include: six degree of freedom, low mass and high structural rigidity. However, a good understanding of the kinematics of the structure is required for successful implementation of such a machine tool. Two attributes of a Stewart platform based machine tool — the workspace and dexterity are investigated in this work. The workspace is analyzed using a point discretization method in which discrete points are checked by the inverse kinematic solution of the Stewart Platform. The workspace thus obtained is presented graphically for various positions and orientations of the end effector. The dexterity of the workspace is studied by calculating the condition number for each discrete point. The results of the workspace and dexterity study are explained. The plots of workspace and dexterity may be used in the design stage for efficient utilization of the available workspace for a given machining operation.
High Performance and Self-Humidifying of Novel Cross-Linked and Nanocomposite Proton Exchange Membranes Based on Sulfonated Polysulfone

The introduction of inorganic additive or nanoparticles into fluorine-free proton exchange membranes (PEMs) can improve proton conductivity and have considerable effects on the performance of polymer electrolyte membrane fuel cells. Based on the sol–gel method and in situ polycondensation, novel cross-linked PEM and nanocomposite PEMs based on a sulfonated polysulfone (SPSU) matrix were prepared by introducing graphene oxide (GO) polymeric brushes and incorporating Pt-TiO2 nanoparticles into an SPSU matrix, respectively. The results showed that the incorporation of Pt-TiO2 nanoparticles could obviously enhance self-humidifying and thermal stability. In addition, GO polymer brushes fixed on polymeric PEM by forming a cross-linked network structure could not only solve the leakage of inorganic additives during use and compatibility problem with organic polymers, but also significantly improve proton conductivity and reduce methanol permeability of the nanocomposite PEM. Proton conductivity, water uptake and methanol permeability of the nanocomposite PEM can be up to 6.93 mS cm−1, 46.58% and be as low as 1.4157 × 10−6 cm2 s−1, respectively, which represent increases of about 70%, about 22% and a decrease of about 40%, respectively, compared with that of primary SPSU. Therefore, the synergic action of the covalent cross-linking, GO polymer brush and nanoparticles can significantly and simultaneously improve the overall performance of the composite PEM.
Lost in Optimization of Water Distribution Systems: Better Call Bayes

The main goal of this paper is to show that Bayesian optimization could be regarded as a general framework for the data driven modelling and solution of problems arising in water distribution systems. Hydraulic simulation, both scenario based, and Monte Carlo is a key tool in modelling in water distribution systems. The related optimization problems fall in a simulation/optimization framework in which objectives and constraints are often black-box. Bayesian Optimization (BO) is characterized by a surrogate model, usually a Gaussian process, but also a random forest and increasingly neural networks and an acquisition function which drives the search for new evaluation points. These modelling options make BO nonparametric, robust, flexible and sample efficient particularly suitable for simulation/optimization problems. A defining characteristic of BO is its versatility and flexibility, given for instance by different probabilistic models, in particular different kernels, different acquisition functions. These characteristics of the Bayesian optimization approach are exemplified by the two problems: cost/energy optimization in pump scheduling and optimal sensor placement for early detection on contaminant intrusion. Different surrogate models have been used both in explicit and implicit control schemes. Showing that BO can drive the process of learning control rules directly from operational data. BO can also be extended to multi-objective optimization. Two algorithms have been proposed for multi-objective detection problem using two different acquisition functions.
Synthesis and characterization of new aromatic copoly(ether amide)s bearing 4-trifluoromethylphenyl-2,6-diphenylpyridyl moieties in the main chain

A series of new aromatic fluorinated copoly(ether amide)s containing 4-(4-trifluoromethylphenyl)-2,6-diphenylpyridyl moiety with high molecular weight were prepared by a low-temperature solution polycondensation of terephthaloyl chloride with 4-(4-trifluoromethylphenyl)-2,6-bis(4-aminophenyl)pyridine and 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene with various mole ratios of the two monomers ranged from 20/80 to 80/20. All polymers were amorphous and soluble in common organic solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide and tetrahydrofuran at room temperature or upon heating at 70oC, and could be solution cast into transparent, tough, and flexible films with tensile strengths of 66.9–80.2 MPa, tensile moduli of 1.84–2.03 GPa, and elongations at break of 11.8–20.7%. These new polyamides displayed good thermal stability with gradually increasing of glass temperatures of 259–285oC as an increase of the 4-(4-trifluoromethylphenyl)-2,6-diphenylpyridyl component, the temperature at 10% weight loss of 476–505oC, and the residue of 55–61% at 750oC in nitrogen. They also exhibited low dielectric constants of 3.11–3.38 (1 MHz), low moisture absorption in the range of 1.43–1.75%, and high transparency with an UV–vis absorption cut-off wavelength in the 350–368 nm range.
For Servo Test Gyroscope Drift Equipment Error Analysis and Compensation

In order to improve measurement-precision of the Gyro,the gyroscope experiment is completed based on gyroscope servo technology.The error sources of gyroscope servo technology are analyzed in process of measurement,and the impact of these error sources on measurement is evaluated.The mathematical model established reflects relationship of equipment error and test results.The compensation methods of error are given in the model.The experimental results proof that test precision is improved after compensation.