Current and Temperature Dependent Matching Fields in Nb Film of Rectangular Array of Holes

Nanoengineered periodic array of holes on superconducting thin films have a great interest due to their excellence for the studies of the vortex pinning mechanisms in the type-II superconductors. Rectangular array of holes has been fabricated over a microbridge of Nb superconducting thin film by e-beam lithography. Rectangular array of holes have two type of scenario, at low magnetic fields matching effects are sharp and narrow while at high fields wide and shallower. In this work, we study the matching pinning effect by the artificial hole array in superconducting Nb thin films. We observed that as the inter distance between holes is decreased; the sharp matching effects become dominant and vice versa.     

Model-based diagnosis of special causes in statistical process control

Industry has recognized that effective use of automated diagnostic software can greatly enhance process quality and productivity. Simultaneously, significant advances have been made in the technologies of process modelling, using techniques such as neural networks, regression methods, and various analytical approaches. Here we will present a simple method to perform model-based diagnosis. The method is simple to implement, intuitively appealing, and requires information that should be standardly available. The method requires as input current process data, set-point information, and a predictive process model, and outputs a table of diagnostic scores which indicate the likelihood of a particular factor being the cause of an observed special cause on a statistical process control chart.     

Microstructure and mechanical properties of two-phase Fe30Ni20Mn20Al30: part II mechanical properties

This paper describes the mechanical properties of B2/L2₁ two-phase Fe₃₀Ni₂₀Mn₂₀Al₃₀ (at.%) in both the as-cast condition and after a 72 h anneal at 823 K. The temperature dependence of the compressive strength of Fe₃₀Ni₂₀Mn₂₀Al₃₀ showed three distinct regions: (1) brittle fracture at low temperature, (2) plastic flow with a rapid decline in yield strength from 1500 to 250 MPa from the brittle-to-ductile transition temperature (BDTT) to 873 K, and (3) a slight decrease in yield strength to ~150 MPa from 873 to 1073 K. Interestingly, the BDTT (573 K) exhibited by the coarser microstructure present in 72 h annealed material was lower than that of the as-cast alloy (623 K). Using both differential scanning calorimetry and in situ heating in a transmission electron microscope, an L2₁-to-B2 transition was found at 750 ± 25 K. A mixture of intergranular fracture and transgranular cleavage was observed after room temperature compression while only cleavage was found at 673 K. All the specimens deformed extensively without fracture when tested at temperatures higher than 673 K. The strain rate had little effect on the strength at 573 K and a moderate effect at 873 K with a strain-rate sensitivity exponent value of 0.1.     

Comments on ‘A Lur'e-type Lyapunov function for multimachine power systems with transfer conductances’

This note shows that the Lyapunov function constructed for the example multimachine power system by Saeki et al. (1985) is in error. The derivative of the Lyapunov function along the trajectories is not negative-semidefinite. This problem raises questions as to whether the hypotheses of Saeki et al. (1985 Theorem 1) can be satisfied in a multimachine power system with transfer conductances.     

Association of size‐fractionated indoor particulate matter and black carbon with heart rate variability in healthy elderly women in Beijing

Associations between size‐fractionated indoor particulate matter (PM) and black carbon (BC) and heart rate variability (HRV) and heart rate (HR) in elderly women remain unclear. Twenty‐nine healthy elderly women were measured for 24‐hour HRV/HR indices. Real‐time size‐fractionated indoor PM and BC were monitored on the same day and on the preceding day. Mixed‐effects models were applied to investigate the associations between pollutants and HRV/HR indices. Increases in size‐fractionated indoor PM were significantly associated with declines in power in the high‐frequency band (HF), power in the low‐frequency band (LF), and standard deviation of all NN intervals (SDNN). The largest decline in HF was 19% at 5‐minute moving average for an interquartile range (IQR) increase (24 μg/m³) in PM_0.5. The results showed that smaller particles could lead to greater reductions in HRV indices. The reported associations were modified by body mass index (BMI): Declines in HF at 5‐minute average for an IQR increase in PM_0.5 were 34.5% and 1.0% for overweight (BMI ≥25 kg/m²) and normal‐weight (BMI <25 kg/m²) participants, respectively. Moreover, negative associations between BC and HRV indices were found to be significant in overweight participants. Increases in size‐fractionated indoor PM and BC were associated with compromised cardiac autonomic function in healthy elderly women, especially overweight ones.     

Effect of annealing temperature on structural and magnetic properties of Co2TiO4 ceramics prepared by sol-gel method

In this paper, polycrystalline Co₂TiO₄ ceramics have been synthesized using a sol-gel process followed by annealing at different temperatures. The lattice size and the average grain size of the samples increases with rise in annealing temperature. The temperature-dependent inverse paramagnetic susceptibilities recorded under zero-field-cooling condition have been fitted according to the Néel's expression for ferrimagnets. Subsequently, the molecular field constants and the corresponding exchange constants have been calculated. The fitting result shows that the magnetic interaction in the system becomes weaker as the annealing temperature rises. In addition, negative magnetization is observed during field-cooling process. The higher annealing temperature is beneficial to the growth of tetrahedral sublattice, leading to a decrease on compensation temperature. Furthermore, magnetization hysteresis loops for all the samples demonstrate the crucial role of grain size on the magnetic properties.     

Influence of Pluronic coating formulation on iron oxide nanoparticle transport in natural and oil-impacted sandy aquifer media

Targeted delivery of nanoparticles has the potential to enhance remediation and characterization of sites contaminated with non-aqueous phase liquids (NAPLs) by ensuring delivery of treatment or contrast agents to the NAPL/water interface. For a targeted delivery technique to be successful, nanoparticles must be capable of transporting through porous media and binding to NAPLs under relevant geological conditions. In this study, successful targeted delivery of nanoparticles to sandy aquifer material mixed with crude oil was achieved using an active targeting technique based on an amphiphilic polymer coating. It was determined that the molecular structure and concentration of the nanoparticle coating greatly influenced the recovery of nanoparticles injected into saturated columns. Coatings with longer polymer molecules and lower polymer concentrations reduced recovery, and the nanoparticle coating formulation could be adjusted to improve transport while maintaining targeted binding behaviour. This study demonstrated that nanoparticle retention in oil-impacted sand exceeded that of clean sand in flow through experiments, indicating that a nanoparticle targeted delivery strategy for soil contaminated with LNAPLs such as crude oil is possible under the experimental conditions explored.     

Spin-filtering effect in GaAsN: electron-nuclear spin dynamics of Ga<Superscript>3+</Superscript> centers

The impact of Ga³⁺ centers in the spin-filtering effect observed in GaAsN samples is investigated through a model based on the master equation approach. Our results, compared with experimental data, show that, Ga³⁺ are essential to understanding the behavior of the photoluminescence intensity and degree of circular polarization as functions of a Faraday configuration magnetic field. The model presented here takes into account the interplay of Ga²⁺ and Ga³⁺ centers, Zeeman and hyperfine interaction. The various processes that drive the spin-filtering effect, as the spin selective capture of conduction band electrons into Ga centers are also considered here.     

Increasing the Level of Automation in the Forestry Logging Process with Crane Trajectory Planning and Control

Working with forestry machines requires a great deal of training to be sufficiently skilled to operate forestry cranes. In view of this, it would be desirable within the forestry industry to introduce automated motions, such as those seen in robotic arms, to shorten the training time and make the work of the operator easier. Motivated by this fact, we have developed two experimental platforms for testing control systems and motion‐planning algorithms in real time. They correspond to a laboratory setup and a commercial version of a hydraulic manipulator used in forwarder machines. The aim of this article is to present the results of this development by providing an overview of our trajectory‐planning algorithm and motion‐control method, with a subsequent view of the experimental results. For motion control, we design feedback controllers that are able to track reference trajectories based on sensor measurements. Likewise, we provide arguments to design controllers in an open‐loop for machines that lack sensing devices. Relying on the tracking efficiency of these controllers, we design time‐efficient reference trajectories of motions that correspond to logging tasks. To demonstrate performance, we provide an overview of extensive testing done on these machines.