A microscopic formulation of dynamical spin injection in ferromagnetic-nonmagnetic heterostructures

We develop a microscopic formulation of dynamical spin injection in heterostructure comprising nonmagnetic metals in contact with ferromagnets. The spin pumping current is expressed in terms of Green's function of the nonmagnetic metal attached to the ferromagnet where a precessing magnetization is induced. The formulation allows for the inclusion of spin-orbit coupling and disorder. The Green's functions involved in the expression for the current are expressed in real-space lattice coordinates and can thus be efficiently computed using recursive methods.Comment: 18 pages, 6 figure

Charge and Spin Transport in Low-Dimensional Materials

My research has been focused on two main areas. First, electronic transports in chiral carbon nanotubes in the presence of charged adatoms. To study such systems we employed recursive Greens function technique to evaluate the conductance using the Landauer formula. Comparing with the experimental data, we determined the effective amplitude and the range of scattering potentials. In addition, using a similar approach we explained qualitatively an unusual conductance feature in a metallic carbon nanotube. The second part of my study was concerned to the dynamical spin injection and spin currents in low-dimensional materials. We have developed an atomistic model to express the injected spin current in terms of the systems Greens function. The new formulation provides a framework to study the spin injection and relaxation of a system with an arbitrary structure

ANALYSIS OF TIME-LAPSE 3-D VSP DATA FOR SEISMIC MONITORING OF CO2 FLOOD IN WEYBURN FIELD, SASKATCHEWAN

This study explores the potential of VSP data in reservoir studies and particularly in separating the effects of CO2 pore pressure and saturation after fluid injection into the reservoir. It helps establishing robust and reliable links between physical properties of hydrocarbon reservoirs and seismic data. It also reduces the uncertainties of the AVA analysis through constructing a detailed model of first-arrival amplitude decay combining geometric spreading, scattering, and inelastic dissipation. The inversion of seismic data reveals anisotropic variations of geometric attenuation (wavefront curvatures and scattering, denoted ) and the effective attenuation parameter () with depth. Statistical analysis of model uncertainties quantitatively measures the significance of these results. This model correctly predicts the observed frequency-dependent first-arrival amplitudes at all frequencies and can be used for reflected waves. Scattering and geometric spreading (focusing and defocusing of wave fronts) significantly affect seismic amplitudes at lower frequencies and shallower depths. Using of complete well logs, a model of P- and S-wave scattering is derived from direct-wave attenuation observations by numerical and analytical methods. Both approaches reveal fluctuations in the transmitted-energy flux within different depth intervals, and particularly at frequencies above 60 Hz. A randomization of well logs suggests that the upper envelope of the transmitted energy flux (corresponding to strongest transmission) is a reasonable estimate for random scattering. The lower envelope corresponding to the strongest reflectivity appears to be a useful characteristic of the fluctuations in the scattered wavefields. Once these ‘random’ and ‘fluctuation’ attenuations are modeled, they can be isolated from the intrinsic and geometric effects. Finally, three amplitude-based methods are used to separate the effects of CO2 pressure and saturation in the Weyburn reservoir. Based on these results, an area close to an injection well within the southern part of the study area is interpreted as having the highest pressure, and the area between the northern and eastern wells show the highest CO2 saturation. Near the center of the study area, the effects of CO2 saturation and pressure appear to be the weakest

Steering line waves at a dual metasurface for optical applications

Line waves are defined as confined edge modes propagating at the interface of dual electromagnetic metasurfaces that preserve mirror reflection symmetries. Previous works have theoretically and practically explored these waves, showing that they occur at microwave regimes and terahertz ranges. It is also demonstrated that line waves can happen when there is a symmetric resistance discontinuity from negative to positive values and a uniform surface reactance. Line waves are of tunable mode confinement, direction-dependent polarizations, and singular field enhancement. This study presents a graphene patch design and demonstrates that the line waves associated with this structure can travel in the optical domain. Our design consists of a graphene metasurface on an epsilon near zero (ENZ) substrate. While our approach considers both dual reactive impedances and homogenous reactive ones, we only concentrate on line wave utilization in a dual-impedance structure

CONTEXTUALIZATION OF DEMING AND CROSBY'S THEORIES IN IMPROVING EDUCATIONAL INSTITUTIONS

This research is a figure thinking study focused on two quality thinkers, Deming and Crosby. Using the Library Reseach research method presented in the form of argumentative approaches and descriptive analysis. The 14 quality points expressed by Deming and Crosby are interesting for further investigation, Deming emphasizes the scope of the concept and the theory of quality management, while Crosbye focuses on the construction of the components of the quality management as well as the details of its implementation. In this article, the author offers the theoretical concepts and contextualization of quality management Deming and Crosby in improving the quality of education with the concept of "Circle of Three Layers". In this concept there is a continuous blend between theory and context. The working step of this concept is to emphasize the development of theory (theorytical improvement) and the contextualization of the theory in the educational institutions, so that after the process of the contextalization theory is carried out, then it is expected that the institutions of education can improve the quality (quality improving) and competitive quality (competitive quality). (periodic evaluation)

Helminth parasites fauna of the green toad, Bufo variabilis, Laurenti, 1768 (Anura: Bufonidae) from the Fars Province, Iran

The green toad, Bufo variabilis has been a common species of toads in Iran with a wide distribution in most provinces. The main goal of this study was to determine the helminth parasite fauna of B. variabilis in southwest of Iran. Among 30 toads inspected for helminth infection from different sites, 100% harbored one or more parasite species. Some toads were afflicted by intestinal obstruction, due to the infection with a large number of cestodes. Twenty-eight cases (93%) had mixed infection with cestodes (in intestine) and nematodes (in lung). Also, a toad was infected with a single monogenean parasite in its urinary bladder. The identified helminth parasites were monogenean, Polystoma viridis; cestode, Nematotaenia dispar and a species of nematode, Rhabdias ranae. This study reports for the first time the presence of nematode species R. ranae in B. variabilis in Iran

An overview of illegal parrot trade in Maluku and North Maluku Provinces

Maluku is widely considered as a global avifauna hotspot. However, illegal parrot trades threatens numerous species to extinction. To date, there is no study on the extent of illegal trade in Maluku, which as a result, hampers efforts at targeting conservation initiatives. The aims of this study are to identify the pattern of illegal parrot trade, to identify factors that contribute to illegal parrot trade, and to identify actors involved in illegal parrot trade in Maluku and North Maluku Provinces. The study found that the number of wildlife rescued in 2018 was 1,402 individuals. Surprisingly, 84% (1,177 individuals) of the rescued wildlife were birds and approximately 96% (1,135 individuals) of the birds were parrots. Furthermore, the most commonly rescued parrots (90%) were from illegal trade seizures, and the remainder were handed over voluntarily by local communities. These trends indicate that the traffic of illegal parrot trade is extremely high. Meanwhile, the small number of handovers for birds indicates that there is an insufficient understanding and awareness among locals about wildlife laws and ecological values. The study identified three factors contributing to illegal parrot trade, which are the high potential for obtaining parrots with exotic appearances; the economic value of wild-caught parrots; and overall accessibility. The characteristics of the trade involved actors that can be defined as subsistence and opportunist harvesters, that work with several intermediaries, and consumers demand for pets. To overcome these challenges, there are two strategies which are proposed based on this research: (1) expand the upstream strategy focusing on protecting parrots in their habitats and empowering local communities to be involved in conservation; and (2) engage more on downstream strategies of emphasizing law enforcement and raising awareness

An investigation on the helminth parasites of Caspian turtle (Mauremys caspica) with a taxonomic note on recovered Falcaustra Lane, 1915 (Nematoda: Kathlaniidae) and Spiroxys Schneider, 1866 species (Nematoda: Gnathostomatidae)

In this study, the digestive tracts of the Caspian turtles (Mauremys caspica) were investigated for the presence of helminth infections. Specimens of roundworms were recovered from the large intestine and stomach of the Caspian turtles. The morphologic measures revealed the infection with nematodes of the genus Falcaustra and Spiroxys. However, some differences were found in the collected Falcaustra specimens compared to the previous descriptions. In parallel, samples were analyzed by sequencing of the ribosomal gene targets. The phylogenetic analysis showed that the Falcaustra species as members of superfamily Cosmocercoidea were grouped with some members of Ascaridoidea and Spiruroidea. Despite the significant morphologic differences, Spiroxys species formed a sister group with ascaroid and cosmocercoid roundworms. Therefore, our molecular findings revealed that the taxonomic position of both nematodes need be revised

The estimate of amplitude and phase of harmonics in power system using the extended kalman filter

Nowadays, the amplitude of the harmonics in the power grid has increased unwittingly due to the increasing use of the nonlinear elements and power electronics. It has led to a significant reduction in power quality indicators. As a first step, the estimate of the amplitude, and the phase of the harmonics in the power grid are essential to resolve this problem. We use the Kalman filter to estimate the phase, and we use the minimal squared linear estimator to assess the amplitude. To test the aforementioned method, we use terminal test signals of the industrial charge consisting of the power converters and ignition coils. The results show that this algorithm has a high accuracy and estimation speed, and they confirm the proper performance in instantaneous tracking of the parameters

Human trajectory prediction using LSTM with Attention mechanism

In this paper, we propose a human trajectory prediction model that combines a Long Short-Term Memory (LSTM) network with an attention mechanism. To do that, we use attention scores to determine which parts of the input data the model should focus on when making predictions. Attention scores are calculated for each input feature, with a higher score indicating the greater significance of that feature in predicting the output. Initially, these scores are determined for the target human position, velocity, and their neighboring individual's positions and velocities. By using attention scores, our model can prioritize the most relevant information in the input data and make more accurate predictions. We extract attention scores from our attention mechanism and integrate them into the trajectory prediction module to predict human future trajectories. To achieve this, we introduce a new neural layer that processes attention scores after extracting them and concatenates them with positional information. We evaluate our approach on the publicly available ETH and UCY datasets and measure its performance using the final displacement error (FDE) and average displacement error (ADE) metrics. We show that our modified algorithm performs better than the Social LSTM in predicting the future trajectory of pedestrians in crowded spaces. Specifically, our model achieves an improvement of 6.2% in ADE and 6.3% in FDE compared to the Social LSTM results in the literature.Comment: 10 pages, 8 figure