Discrete interferences optimum beamformer in correlated signal and interfering noise

This paper introduces a significant special situation where the noise is a collection of D-plane interference signals and the correlated noise of D+1 is less than the number of array components. An optimal beamforming processor based on the minimum variance distortionless response (MVDR) generates and combines appropriate statistics for the D+1 model. Instead of the original space of the N-dimensional problem, the interference signal subspace is reduced to D+1. Typical antenna arrays in many modern communication networks absorb waves generated from multiple point sources. An analytical formula was derived to improve the signal to interference and noise ratio (SINR) obtained from the steering errors of the two beamformers. The proposed MVDR processor-based beamforming does not enforce general constraints. Therefore, it can also be used in systems where the steering vector is compromised by gain. Simulation results show that the output of the proposed beamformer based on the MVDR processor is usually close to the ideal state within a wide range of signal-to-noise ratio and signal-to-interference ratio. The MVDR processor-based beamformer has been experimentally evaluated. The proposed processor-based MVDR system significantly improves performance for large interference white noise ratio (INR) in the sidelobe region and provide an appropriate beam pattern.

Estimating the Cosmological Constant from Shadows of Kerr–de Sitter Black Holes

The Event Horizon Telescope collaboration has revealed the first direct image of a black hole, as per the shadow of a Kerr black hole of general relativity. However, other Kerr-like rotating black holes of modified gravity theories cannot be ignored, and they are essential as they offer an arena in which these theories can be tested through astrophysical observation. This motivates us to investigate asymptotically de Sitter rotating black holes wherein interpreting the cosmological constant Λ as the vacuum energy leads to a deformation in the vicinity of a black hole—new Kerr–de Sitter solution, which has a richer geometric structure than the original one. We derive an analytical formula necessary for the shadow of the new Kerr–de Sitter black holes and then visualize the shadow of black holes for various parameters for an observer at given coordinates (r0,θ0) in the domain (r0,rc) and estimate the cosmological constant Λ from its shadow observables. The shadow observables of the new Kerr–de Sitter black holes significantly deviate from the corresponding observables of the Kerr–de Sitter black hole over an appreciable range of the parameter space. Interestingly, we find a finite parameter space for (Λ, a) where the observables of the two black holes are indistinguishable.

Development of Enhanced Range, High Q, Passive, Chipless RFID Tags for Continuous Monitoring and Sensing Applications

A high Q planar chipless RFID tag with high sensitivity is proposed for communication applications. In particular, the tag structure is composed of a complementary spiral structure (CSS) that is able to provide high sensitivity and compactness. A semi analytical formula for the design of a single bit tag is derived, and the behaviour of the CSS is analysed for different dielectric substrates. Different tags, composed of up to a set of eight resonators, have been numerically and experimentally assessed. In particular, a system prototype composed of a reader and a set of tags are fabricated and experimentally assessed as a proof of concept. The system provided an operative range of tens of centimetres (a maximum operative range of 65 cm). The obtained results are quite promising and the agreement between simulated and measured results are found to be good.

Effect of heater size on heat transfer in a falling liquid film

Проведены расчеты полей скорости и температуры, а также положение границы раздела жидкость-газ при стекании тонкой пленки жидкости по плоской подложке, наклоненной к горизонту. На подложке расположен нагреватель квадратной формы, мощность которого фиксирована, а размеры варьировались в ходе расчетов:- одним из перспективных методов отвода высоких тепловых потоков от электронного оборудования являются технологии, использующие тонкие пленки жидкости, движущиеся по охлаждаемой поверхности. Целью работы было исследование зависимости динамики и теплообмена в пленки от размера нагревателя;- на основе разработанной трехмерной нестационарной модели движения проведены расчеты теплообмена в движущейся поенке. При этом учитывалось действие всех основных физческих факторов при их взаимодействии: диффузионный и конвективный теплопереносы, зависимость вязкости от температуры, термокапиллярный эффект, появление и эволюция поверхностных деформаций;- установлено, что размер нагревателя существенно влияет на поля температуры и поверхностные деформации, а также на значение температурных экстремумов. Выведена аналитическая формула для расчета наибольшего достигаемого на подложке превышения температуры её среднего значения;- результаты могут применяться при проектировании систем охлаждения электронного оборудования. On the basis of the developed three-dimensional non-stationary model of motion, calculations of heat transfer in a moving roll were carried out. In this case, the action of all the main physical factors during their interaction was taken into account: diffusion and convective heat transfer, the dependence of viscosity on temperature, the thermocapillary effect, the appearance and evolution of surface deformations.  it was found that the size of the heater significantly affects the temperature fields and surface deformations, as well as the value of temperature extremes. An analytical formula is derived for calculating the maximum temperature rise attainable on the substrate of its average value.

Clearing-induced tisssue shrinkage: A novel observation of a thickness size effect

The use of clearing agents has provided new insights in various fields of medical research (developmental biology, neurology) by enabling examination of tissue architecture in 3D. One of the challenges is that clearing agents induce tissue shrinkage and the shrinkage rates reported in the literature are incoherent. Here, we report that for a classical clearing agent, benzyl-alcohol benzyl-benzoate (BABB), the shrinkage decreases significantly with increasing sample size, and present an analytical formula describing this.

Inferring the DNA replication origin density landscape in human cells from replication timing and fork directionality data

The determinants of the locations and firing times of the multiple replication origins are still elusive in human and other metazoan organisms. Experiments can independently profile mean replication timing (MRT) and replication fork directionality (RFD) genome-wide. In the hypothesis of a constant replication fork speed, MRT and RFD are related to each other by an analytical formula so are a priori equivalent. However, we show here that experimental noises result in MRT and RFD profiles containing information at different spatial frequencies. We further demonstrate that one can compute an origin density landscape that, when inserted in an appropriate simulation framework, jointly predicts experimental MRT and RFD profiles with an unprecedented precision. We also extract an analytical formula linking intrinsic origin efficiency with observed origin efficiency and MRT. We then compare the computed origin density landscape with experimental distributions of potential origins (ORC, MCM) or actual initiation events (Bubble-seq, SNS-seq, OK-seq). The results indicate that MRT and RFD data are highly consistent with each other, that our simple model suffices to capture the replication dynamics during S phase given an appropriate initiation probability landscape, but that the density of potential origins is not the sole determinant of this landscape.

AN APPROXIMATE METHOD TO PRESENT THE BUCKLING STRENGTH OF A GRILLAGE IN A PROBABILISTIC FORM

An approximate method for calculation in probabilistic terms of the buckling strength of a grillage under unidirectional in-plane compression is proposed. The geometric properties of longitudinals and transverses and the mechanical properties (yield stress and modulus of elasticity) of the material they are built from are treated as random parameters that may change over ship’s service life. The cumulative distribution function of the grillage’s critical buckling strength is calculated by using an analytical formula for multitude sets of input parameters while all of them having the same level of certainty. The assumption is that the critical buckling strength has the same (or very similar) level of certainty as that of the input parameters. The accuracy of the proposed approximate method is relatively high (the maximal error is around 2%). It is recommended for use when specialized computer programs for application of Monte Carlo simulation method are not available. The method does not require a complicated specialized computer program and can be run on EXCEL computer program.

Quantitative Assessment and Measurement of X-ray Detector Performance and Solid Angle in the Analytical Electron Microscope

A wide range of X-ray detectors and geometries are available today on transmission/scanning transmission analytical electron microscopes. While there have been numerous reports of their individual performance, no single experimentally reproducible metric has been proposed as a basis of comparison between the systems. In this paper, we detail modeling, experimental procedures, measurements, and specimens which can be used to provide a manufacturer-independent assessment of the performance of an analytical system. Using these protocols, the geometrical collection efficiency, system peaks, and minimum detection limits can be independently assessed and can be used to determine the best conditions to conduct modern hyperspectral and/or spectrally resolved tomographic analyses for an individual instrument. A simple analytical formula and specimen is presented which after suitable system calibrations can be used to experimentally determine the X-ray detector solid angle.

Analytical models for inter-layer tunneling in two-dimensional materials

Analytical formula of the transmission function of the inter-layer intra-band tunneling is derived for coupled narrow two-dimensional materials. Analytical models of the intra-band tunneling conductance G, the transmission function of the inter-layer band-to-band tunneling, and the maximum band-to-band tunneling current Imax, are also obtained. G and Imax are shown to exhibit different characteristics depending on the channel length.