Miracle-dz/UniFAR-FTUs huggingface dataset:
Charged black holes in the infinite derivative theory of gravity

The infinite derivative theory of gravity is a generalization of Einstein gravity with many interesting properties, but the black hole solutions in this theory are still not fully understood. In the paper, we concentrate on studying the charged black holes in such a theory. Adding the electromagnetic field part to the effective action, we show how the black hole solutions around the Reissner–Nordström metric can be solved perturbatively and iteratively. We further calculate the corresponding temperature, entropy and electrostatic potential of the black holes and verify the first law of thermodynamics.
A Comparison Study of Normal-Incidence Acoustic Impedance Measurements of a Perforate Liner

The eduction of the acoustic impedance for liner configurations is fundamental to the reduction of noise from modern jet engines. Ultimately, this property must be measured accurately for use in analytical and numerical propagation models of aircraft engine noise. Thus any standardized measurement techniques must be validated by providing reliable and consistent results for different facilities and sample sizes. This paper compares normalincidence acoustic impedance measurements using the two-microphone method of ten nominally identical individual liner samples from two facilities, namely 50.8 mm and 25.4 mm square waveguides at NASA Langley Research Center and the University of Florida, respectively. The liner chosen for this investigation is a simple single-degree-of-freedom perforate liner with resonance and anti-resonance frequencies near 1.1 kHz and 2.2 kHz, respectively. The results show that the ten measurements have the most variation around the anti-resonance frequency, where statistically significant differences exist between the averaged results from the two facilities. However, when the sample-to-sample variation and the uncertainty of the measurement of each individual sample estimate are taken into account for the data measured at the University of Florida, both data sets agree to within experimental uncertainty at all other frequencies. These results thus provide evidence that the size of the present samples do not significantly influence the results away from antiresonance.
Detection and suppression of corona discharges during PD-measurement by means of RI-reception

In most cases sensitive on-site partial discharge (PD)-measurement on an apparatus is impossible in the presence of corona discharges at the high voltage conductors or near to the apparatus. A separation of internal PD and external corona discharges by pulse shape classification isn't possible because of the bandlimiting measuring method of the conventional PD measuring instruments. The presented approach makes use of the radiated electromagnetic fields of corona discharges in the frequency range up to 100 MHz in order to get a specific pulse classification criteria. The reception of the electromagnetic (e.m.) fields by means of rod or loop antennas connected with a wide band measuring receiver provides a signal in addition to the bandlimited signal of the PD measuring circuit. By signal correlation it is possible to eliminate the corona pulses in the PD signal. Measurements in a laboratory set-up were performed. The results of the application of the new filter and correlation method are shown. <<ETX>>
Virtual Reality versus Real–World Space: Comparing Perceptions of Brightness, Glare, Spaciousness, and Visual Acuity

Virtual reality (VR) headsets exhibit great potential for conducting interior design research in immersive digital settings; however, additional studies are needed to map out limitations for their use to simulate real–world settings. We investigated how participant perceptions of a single interior environment varied among a real–world space (R) and two surrogate VR spaces (one made with 360° spherical photography and one made with 360° spherical digital rendering). A total of 42 undergraduate, interior design students were randomly assigned to one of two experiments, resulting in two groups of 21 students. Each participant completed a visual acuity task and evaluated perceived brightness, glare, and spaciousness within the real–world space and one of the two surrogate VR environments. Participants reported acceptable baseline levels of perceived realism in both VR environments. There was no significant difference between the rendered–VR simulation and real–world space for brightness, glare, and spaciousness, while the photographed–VR simulation was seen as significantly brighter and glaring. Performance on the visual acuity task was significantly lower in both VR simulations than in the real–world–approximating the difference between 20/20 and 20/60 vision. Implications and strategies for effective deployment of VR simulations in interior design research are discussed.
A study of the quadrifilar helix antenna for Global Positioning System (GPS) applications

An analytic model for computing the radiation properties of the quadrifilar helix volute antenna is discussed and various design considerations for GPS applications are presented. The effects of modifying the antenna length and diameter on the antenna amplitude and phase performance are presented, and using the antenna for dual-frequency operation is discussed. The effects of phase imbalances are presented and compared with measured pattern anomalies. >
From single layer to multilayer networks in mild cognitive impairment and Alzheimer’s disease

We investigate the alterations of functional networks of patients suffering from mild cognitive impairment and Alzheimer’s disease (AD) when compared to healthy individuals. Departing from the magnetoencephalographic recordings of these three groups, we construct and analyse the corresponding single layer functional networks at different frequency bands, both at the sensors and the regions of interest (ROI) levels. Different network parameters show statistically significant differences, with global efficiency being the one having the most pronounced differences between groups. Next, we extend the analyses to the frequency-band multilayer networks (MN) of the same dataset. Using the mutual information as a metric to evaluate the coordination between brain regions, we construct the αβ MN and analyse their algebraic connectivity at baseline λ 2−BSL (i.e., the second smallest eigenvalue of the corresponding Laplacian matrices). We report statistically significant differences at the sensor level, despite the fact that these differences are not clearly observed when networks are obtained at the ROIs level (i.e., after a source reconstruction procedure). Next, we modify the weights of the inter-links of the multilayer network to identify the value of the algebraic connectivity λ 2−T leading to a transition where layers can be considered to be fully merged. However, differences between the values of λ 2−T of the three groups are not statistically significant. Finally, we developed nested multinomial logistic regression models (MNR models), with the aim of predicting group labels with the parameters extracted from the MN (λ 2−BSL and λ 2−T ). Using these models, we are able to quantify how age influences the risk of suffering AD and how the algebraic connectivity of frequency-based multilayer functional networks could be used as a biomarker of AD in clinical contexts.
Design and implementation of filters using transfer functions in the Z domain

In this paper, a novel approach composed of digital signal-processing techniques and optimization algorithms is developed to design and implement filters at microwave frequencies. The design phase begins with the adoption of digital filter prototypes and the implementation phase is facilitated by using both parametric modeling techniques and optimization algorithms. All the zeros of digital filter prototypes are removed first; the remaining part of the prototypes is then transformed to an autoregressive (AR) process by parametric modeling techniques. The values of characteristic impedances of transmission lines synthesizing the filters are adjusted according to the AR process by optimization algorithms. Both low-pass and bandpass filters are designed and then implemented in the form of a microstrip line, and their frequency responses are measured to validate the novel approach.
Built-in Self-Test and Calibration of Mixed-signal Devices

Wide adoption of deep sub-micron and nanoscale technologie s in the modern semiconductor industry is resulted in very large complex mixedsignal devices. It has then become more difficult to estimate and control device parameter s, which are now increasingly vulnerable to fabrication process variations. Conventiona l design-for-test (DFT) methods have been already well studied for digital circuitry to ensu re verification of its functionality and fault coverage. Built-in self-test (BIST) approaches hav e been developed for design automation of digital ICs. However, such DFT techniques cann ot be applied to analog and mixed-signal circuits directly. Therefore, new technique s must be employed to detect faults in analog components and to provide certain level of calibra tion capability to dynamically adjust the parameters of an analog device for better yield of chips. The most important analog devices in a mixed-signal system-on-chip (SoC) are analo g-to-digital converter (ADC) and digital-to-analog converter (DAC). Such converters tra nsfer data between digital and analog circuits and convert analog signals to digital bits o r vice versa. In this research, novel digital signal processor (DSP)-based post-fabricat ion process-independent BIST approaches and variation tolerant design technique for ADC an d DAC are studied. We use a sigma-delta modulation technique for measurement and a pol ynomial fitting algorithm for device calibration. In the proposed technique, a digital si gnal processor is programmed and used as test pattern generator (TPG), output response analy zer (ORA) and test control unit. The polynomial fitting algorithm characterizes the nonline arity errors and the polynomial is used to generate compensating signals to reduce nonlinea rity rrors to±0.5LSB. This ii technique can be applied to other digitally-controllable m ixed-signal devices and a general test-characterization-calibration approach modeled aft er this work can be developed to detect, measure, and compensate nonlinearity errors caused b y device parameter deviations.
Test Procedure for Axially Loaded Bucket Foundations in Sand (Large Yellow Box)

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A Multimode Transmitter in 0.13 m CMOS Using

This paper presents a system-independent trans- mitter architecture based on a direct-digital RF-modulator which combines the D/A conversion, up-conversion, unwanted sideband rejection, power control, and part of the digital image-rejection filtering into a single mixed-signal circuit block. The multimode capability of the architecture is demonstrated with WCDMA, EDGE, and WLAN system requirements. The modulator achieves 90 dB of power control range and with an external power amplifier module, WCDMA EVM of less than 2% from signal powers of 20 dBm to 25 dBm. The noise floor level defined by the quan- tization noise at 190 MHz offset from the carrier is 150 dBc/Hz measured at the output of the PA with 25 dBm signal power. The analog power consumption with the maximum signal power level is 92 mW and scales down to 46 mW when reducing the signal level to 43 dBFS. The digital power consumption is 65 mW. The chip is implemented with a standard 0.13 m 1.2 V digital CMOS with total silicon area of 4 mm .
Alien amphipods (Arthopoda; Crustacea) in the Tista Estuary, Halden, southeastern Norway

Two new amphipods for Norway Melita nitida and Corophium multisetosum (Crustacea; Amphipoda) were registered in brackish waters in the Tista Estuary in Halden, southeastern Norway. Both species were found in the samples from Tista’s outlet into the Idde Fjord, C. multisetosum in the beach zone and M. nitida at about 4 m depth. Melita nitida is a North American species first found in Europe in the Netherlands in 1998, and since then dispersed into the Baltic Sea via the Kiel Canal and now also found several places on the German Baltic Sea coast and in the Black Sea. Corophium multisetosum was collected even before the 1920s in Western Europe, and is considered native for Europe, whereas its relationship to North America is more ambiguous. From the British Isles and the Netherlands, it seems to have spread to Germany, Poland, Denmark and Sweden, and at present Norway. Until now the two species were found in small numbers at the Norwegian sites and their influence on the total benthic community is probably negligible in this initial phase. The Tista Estuary in Halden apparently appears to be a hotspot for alien brackish water species in Norway. Generally estuaries, with their combination of brackish water jointly with their unsaturated ecological niches and intensive international ship traffic, seem to possess the highest potential infection rate for aquatic systems with alien acrozoobenthic species.
Refined representation of turbines using a 3D SWE model for predicting distributions of velocity deficit and tidal energy density

Energy sustainability has become one of the most concerned issues around the world, and tidal stream power is one of the promising types of renewable energy with merits of high predictability, relatively low cost, and low environmental impact. Numerical models based on the shallow water equations (SWE) have been applied to assess the energy distribution and environmental impact. In existing SWE models, the effect induced by tidal stream turbines on the fluid is usually represented by bed friction, which is only applicable for far‐field studies. In the current study, a Blade Element Momentum (BEM) model has been developed and integrated into a three‐dimensional (3D) SWE model to improve the accuracy for assessing tidal current energy distributions. Using the BEM approach, state variables can be obtained for a blade element of a turbine rotor. These state variables can be used to calculate the local thrust coefficient, which is introduced for representing the effect of rotors in the 3D SWE models. A 3D SWE model has been refined, by incorporating the proposed BEM model, to simulate the density distribution of a tidal turbine farm. The refined SWE model has been validated against measurements from a flume experiment of turbine arrays. The model performs generally well in predicting the distribution of velocity deficit and the recovery of wakes. In a field‐scale application to a planned tidal power test site, the model was used to predicting the flow field for both a single turbine scenario and a turbine array scenario. Copyright © 2015 John Wiley & Sons, Ltd.
Modeling the airflow field of vortex spinning

Vortex spinning technology adopts a high-speed swirling airflow to rotate the fibers with open-ends to form yarn with real twists. The airflow behavior within the nozzle has a great effect on the yarn-formation process. In this study, a three-dimensional calculation nozzle model and corresponding three-dimensional airflow region model were established to enable the numerical calculation; airflow behavior—pressure, velocity, and the turbulent airflow field, and the streamline of airflow—was investigated in the presence of fiber bundles within the vortex spinning nozzle. Hybrid hexahedral/tetrahedral control volumes were utilized to mesh the grids in the calculation region. To consider airflow diffusion and convection in the nozzle, the Realizable k-ε turbulence model with wall function was adopted to conduct the calculation. Dynamic and static pressure values were obtained by numerical analysis to predict the action of the inner surface of nozzle and the wall resistance on the high-speed swirling airflow. The numerical simulation of dynamic airflow behavior can generate great insight into the details of airflow behavior and its distribution characteristics, and is helpful for understanding the spinning mechanism and promoting optimization of the spinning process.
The elimination of offset errors in dual-slope analog-to-digital converters

A new method of eliminating offset error from a dual-slope analog-to-digital converter is described. Two dual-slope cycles, each with the same fixed time period, are needed for a complete conversion. The converter differs from other converters in that the sum and difference of the unknown and reference voltage, as well as the voltages themselves are integrated. Different combinations yield a number of error-free converters in which the ratio of the two voltages is equal to the ratio of the sum or difference of two time periods. The converters also have a limited computational capability In that useful outputs other than the ratio of the unknown and reference voltages can be obtained. For some of the converters the sum or difference of two time periods yields an output with greatly reduced offset error. Another sum or difference provides a correction factor. In addition, some of the converters require a single reference voltage for the entire positive and negative range of the unknown voltage.
Advanced Fuel Cycles for Fusion Reactors: Passive Safety and Zero-Waste Options

Nuclear fusion is seen as a much ''cleaner'' energy source than fission. Most of the studies and experiments on nuclear fusion are currently devoted to the Deuterium-Tritium (DT) fuel cycle, since it is the easiest way to reach ignition. The recent stress on safety by the world's community has stimulated the research on other fuel cycles than the DT one, based on 'advanced' reactions, such as the Deuterium-Helium-3 (DHe) one. These reactions pose problems, such as the availability of 3He and the attainment of the higher plasma parameters that are required for burning. However, they have many advantages, like for instance the very low neutron activation, while it is unnecessary to breed and fuel tritium. The extrapolation of Ignitor technologies towards a larger and more powerful experiment using advanced fuel cycles (Candor) has been studied. Results show that Candor does reach the passive safety and zero-waste option. A fusion power reactor based on the DHe cycle could be the ultimate response to the environmental requirements for future nuclear power plants.
Recycling Piezo-Crystal Based Sounders from Small (Electronic) Devices into Energy Harvesting Devices

Many small devices now incorporate a sound feedback device using piezo crystal plates of varying sizes (10mm-20mm diameter). After these devices are discarded, the piezo crystal plates are usually of no value other than a curious toy or component. This work presents a potential use of this device (18.8mm diameter unimorph PZT 5H piezo plate) for harvesting energy by mounting it on the wrist (at the base of meta carpal) of human subjects. The subjects were made to walk at an average steady pace of 0.7m/s. The device generated voltage in the range of 180.4mV to 1674.60mV. ANSYS 10 simulation shows that the optimum voltage will be generated at resonance frequency of approximately 204Hz.
The Application of Biometric Identification Technology in ATM System

Biometric identification technology deals with the identification of individuals based on their biological or human behavioral characteristics. Biometric identification method is reliable, anti-counterfeit, convenient and safe. At present there are some insecurity factors in the ATM (automatic teller machine) in bank system. Methods such as combining biological recognition with the ATM machine, adding the face recognition technology, fingerprint recognition, second generation ID card recognition, enhancing automatic identification are developed to improve the security of ATM.
A hybrid optimal backstepping and adaptive fuzzy control for autonomous quadrotor helicopter with time-varying disturbance

In this paper, a hybrid control system called as backstepping adaptive fuzzy control system, which integrates nominal and compensation controller is developed for autonomous quadrotor helicopter with inherent time-varying disturbance. In this hybrid control system, the nominal controller based on backstepping technique is the main controller, and the compensation controller containing a fuzzy control approach is used to eliminate the effect of uncertainties caused by external disturbance. In addition, in order to relax the requirement of prior knowledge on the bound of external disturbance, an online adaptation law is derived. Asymptotical stability of the closed-loop control system is analytically proven via the Lyapunov theorem. For the problem of determining the backstepping control parameters, particle swarm optimization algorithm has been employed. Finally, the designed controller is experimentally evaluated on a quadrotor simulation environment to demonstrate the effectiveness and merits of the theoretical development.
Nogo receptor impairs the clearance of fibril amyloid‐β by microglia and accelerates Alzheimer’s‐like disease progression

Alzheimer's disease (AD) is characterized by the progressive accumulation of β‐amyloid (Aβ)‐containing amyloid plaques, and microglia play a critical role in mediating Aβ clearance. Mounting evidence has confirmed that the ability of microglia in clearing Aβ decreased with aging and AD progress, but the underlying mechanisms are unclear. Previously, we have demonstrated that Nogo receptor (NgR), a receptor for three axon growth inhibitors associated with myelin, can decrease adhesion and migration of microglia to fibrils Aβ with aging. However, whether NgR expressed on microglia affect microglia phagocytosis of fibrils Aβ with aging remains unclear. Here, we found that aged but not young microglia showed increased NgR expression and decreased Aβ phagocytosis in APP/PS1 transgenic mice. NgR knockdown APP/PS1 mice showed simultaneous reduced amyloid burden and improved spatial learning and memory, which were associated with increased Aβ clearance. Importantly, Nogo‐P4, an agonist of NgR, enhanced the protein level of p‐Smad2/3, leading to a significant transcriptional inhibition of CD36 gene expression, which in turn decreased the microglial phagocytosis of Aβ. Moreover, ROCK accounted for Nogo‐P4‐induced activation of Smad2/3 signaling. Finally, the decreasing effect of NgR on microglial Aβ uptake was confirmed in a mouse model of intra‐hippocampal fAβ injection. Our findings suggest that NgR may play an important role in the regulation of Aβ homeostasis, and has potential as a therapeutic target for AD.
To bit or not to bit

Around three years ago Amir Taaki, a London-based code-writer linked to the free software movement, and Donald Norman, a young American entrepreneur, set up the British bitcoin exchange Intersango. In an E&T interview at the time, they were both full of youthful idealism and keen to ensure Intersango was secure and ticked the right regulatory boxes. Today, Taaki lives in the Calafou commune in Barcelona and works on the Dark Wallet bitcoin project backed by Cody Wilson of Liberator 3D-printed gun fame, named by Wired Magazine as one of the '15 Most Dangerous People in the World'. Both Taaki and Norman are also subjects of a $500,000 lawsuit filed in August 2012 in San Francisco by four bitcoin investors who lost money on an exchange called Bitcoinica, which was acquired by Intersango that year. Bitcoinica was a cloud-based exchange - built in five days by a Singaporean teenager - that was hacked before and after Intersango acquired it.