Miracle-dz/UniFAR-FTUs huggingface dataset:
Discrete element modeling of cemented sand and particle crushing at high pressures

This project aims to provide an insight into the behaviour of cemented sand under high pressures, and to further the understanding of the role of particle crushing. The discrete element method is used to investigate the micro mechanics of sand and cemented sand in high-pressure triaxial tests and one-dimensional normal compression. Using the software PFC3D, a new triaxial model has been developed, which features an effective flexible membrane that allows free deformation of the specimen and the natural failure mode to develop. The model is capable of exerting and sustaining high confining pressures. Cementation has been modelled using inter-particle bonds, and a full investigation of the bond properties is presented, highlighting their influence on the macroscopic behaviour (e.g. failure mode and volumetric response). A simple particle breakage mechanism is used to model the one-dimensional normal compression of sand. By considering the stresses induced in a particle due to multiple contacts, and allowing particles to fracture without the use of agglomerates, this work aims to explain the mechanics of normal compression. The influence of the mechanics of fracture on the slope of the normal compression line is investigated, and the normal compression is linked to the evolution of a fractal particle size distribution. A new equation for the one-dimensional normal compression line is proposed, which includes the size-effect on average particle strength, and demonstrates agreement with experimental results. It is shown that this new equation holds for a wide range of simulations. The time dependence of particle strength is incorporated in to this model to simulate one-dimensional creep tests, leading to a new creep law. The normal compression of cemented sand is investigated, and the results show that bonding reduces particle crushing, and that it is both the magnitude and distribution of bond strengths that influence the compression curve of the structured material. Simulations are also presented that show that it is possible to capture the effects of particle crushing in high-pressure triaxial tests on both sand and cemented sand. Particle crushing is shown to be essential for capturing realistic volumetric behaviour, and the intrusive capabilities of the discrete element method are used to gain insight into the effects that cementation has on the degree of crushing.
Multifunction Phased Array Radar for Aircraft and Weather Surveillance

Multifunction phased array radar (MPAR) is a multiagency initiative to investigate the feasibility of replacing the aircraft surveillance and weather radar fleets in the US with a network of phased array radars based on a single, scalable architecture. The Federal Aviation Administration and the National Atmospheric and Oceanic Administration have been collaborating on MPAR risk reduction, which focuses on reducing cost, ensuring that the technology could accomplish all the missions within radar timelines, and developing dual polarization (dual pol) capability. The agencies have completed siting, cost, spectrum, dual pol, and back end studies, among others; have developed three dual pol architectures; and are building operational arrays to demonstrate that the technology can meet the basic needs of the agencies.
APOBEC3A and APOBEC3B are potent inhibitors of LTR-retrotransposon function in human cells

While the ability of APOBEC3G to reduce the replication of a range of exogenous retroviruses is now well established, recent evidence has suggested that APOBEC3G can also inhibit the replication of endogenous retrotransposons that bear long terminal repeats. Here, we extend this earlier work by showing that two other members of the human APOBEC3 protein family, APOBEC3B and APOBEC3A, can reduce retrotransposition by the intracisternal A-particle (IAP) retrotransposon in human cells by 20-fold to up to 100-fold, respectively. This compares to an ∼4-fold inhibition in IAP retrotransposition induced by APOBEC3G. While both APOBEC3G and APOBEC3B specifically interact with the IAP Gag protein in co-expressing cells, and induce extensive editing of IAP reverse transcripts, APOBEC3A fails to package detectably into IAP virus-like particles and does not edit IAP reverse transcripts. These data, which identify human APOBEC3A as a highly potent inhibitor of LTR-retrotransposon function, are the first to ascribe a biological activity to APOBEC3A. Moreover, these results argue that APOBEC3A inhibits IAP retrotransposition via a novel mechanism that is distinct from, and in this case more effective than, the DNA editing mechanism characteristic of APOBEC3G and APOBEC3B.
Optically actuated cantilevers

The aim of this master project was to advance the state of the art in the eld of optothermal actuation of polymer cantilevers. It was a "proof of concept" study where static optothermal actuation of polymer cantilevers was investigated. Optothermal actuation is interesting because it makes it possible to simplify the fabrication process of the devices. In addition, laser actuation o ers exibility and a single laser beam can be used for both actuation and readout simultaneously. However, thermal laser actuation of polymer devices is limited to the static case due to the low heat conduction of polymers. For the optothermal experiments high aspect ratio cantilevers were made in a negative, photosensitive resist called SU-8. The SU-8 was patterned with electron beam lithography (EBL) writing the structures directly into the resist. The SU-8 cantilevers were released by etching away an underlying polymer layer with a complimentary chemistry to SU-8. The SU-8 cantilevers were coated with a thin layer of aluminium, which was employed to absorb the laser light during the experiments. Both micro-sized and nano-sized cantilevers were fabricated demonstrating the scaling option of the fabrication process. Typical dimensions for the micro-cantilevers were 1.5x4. 5x80 μm3 (width x height x length) and 0.35x1. 0x20 μm3 for the nano-cantilevers. Static optothermal measurements with a 532 nm cw laser of the microcantilevers showed bidirectional thermal bending depending on the laser beam position and the cantilever dimensions. The bending was caused by two thermal e ects, the thermal gradient and the bimorph e ect, which both stem from the thermal expansion of the cantilever materials, SU-8 and aluminium. The experimental ndings were supported by transient nite element simulations yielding the temperature distribution of the cantilevers. The results of the simulations showed large variations in maximum temperature and temperature distribution as a function of laser beam position. A set of characterization techniques was applied to the micro-cantilevers. This included dynamic electrostatic measurements and AFM measurements obtaining the resonance frequency of the ground vibrational mode in air and the spring constant, respectively. The resonance frequencies for the SU-8 cantilevers lay in the range 80-100 kHz with the corresponding spring constants at 0.02-0.07 N/m. The mass sensitivity and the cantilever response
Novel forms of inverse analysis to characterise properties of fibre-matrix composites

Novel approaches to the determination of material properties and damage parameters of fibre-matrix composites using inverse analysis are presented. In inverse analysis system identification techniques are used to update some form of mathematical model (normally a FE model) using data from an over-determined number of tests. Initially, pultruded GFRP box-section beams are subjected to a quasi-static impact or bending crush. The results of the impact tests are presented to corroborate those in the literature that have been obtained using simpler geometries such as flat plates. In the first form of inverse analysis, a model-updating approach is applied to progressive tearing damage in pultruded composite box-section beams. The difference between empirical data (from a programme of three-point bend tests) and a FE model is minimised by a genetic algorithm to produce an optimal solution. The solution is in the form of a FE model that can be subsequently analysed to determine the structural integrity of the damaged specimen. Secondly, a unidirectional composite disc from the same GFRP pultruded section is analysed in diametral compression to both verify and improve the validity of the diametral compression test in determining the material properties. Coupons are cut from damaged specimens and test results are presented. The strain distribution within the disc is compared to known laminate theory in order to process data obtained by speckle-shearing interferometry. Finally, speckle-shearing interferometry is used to characterise the response of the pultruded box-section exhibiting progressive tearing damage. Out-of-plane displacement-gradient data is used to determine and characterise damaged regions or flaws. The differences between the need to perform it programme of unequivocal static tests and the collection of full-field optical data are highlighted. It is shown that the shearing interferometry approach is the superior method.
Design and Analysis of a Scalable Third-Party Storage Security Protocol

With the trend of networking and the growth of data value, networked storage security becomes hotpot of research. Aiming at the scalability and security requirement of massive storage system, we proposed a security storage service model combining storage mechanism and security policy and designed a set of scalable third-party security protocols. The protocols adopt public-key cryptography to guarantee the integrity of capability, avoiding the maintenance of shared key. The results of the formal analysis logically ensure the feasibility of the proposed security protocol. Furthermore, the overhead evaluation of the capability illustrates that the security protocol can meet the scalability requirement of storage system.
Material design and discovery with computational materials science

The discovery and design of new materials to improve existing technologies or enable new applications is a driving force for much of the research that takes place in multiple disciplines, including materials science and engineering, condensed matter physics, and materials chemistry. This article reviews the way in which computational methods are being applied to achieve the promise of “materials by design. ” In particular, the article reviews the technologies that have enabled the evolution of computational materials science as a field and its integration with cutting-edge experimental methods. Illustrative applications are discussed where traditional computational methods and materials informatics approaches were applied to design new materials. The article concludes with a discussion of the future outlook of computational materials science within the context of material design and discovery.
Magnetism in dense hexagonal iron

The magnetic state of hexagonal close-packed iron has been the subject of debate for more than three decades. Although Mössbauer measurements find no evidence of the hyperfine splitting that can signal the presence of magnetic moments, density functional theory predicts an antiferromagnetic (afm) ground state. This discrepancy between theory and experiment is now particularly important because of recent experimental findings of anomalous splitting in the Raman spectra and the presence of superconductivity in hexagonal close-packed iron, which may be caused by magnetic correlations. Here, we report results from first principles calculations on the previously predicted theoretical collinear afm ground state that strongly support the presence of afm correlations in hexagonal close-packed iron. We show that anomalous splitting of the Raman mode can be explained by spin–phonon interactions. Moreover, we find that the calculated hyperfine field is very weak and would lead to hyperfine splitting below the resolution of Mössbauer experiments.
Dynamical and Structural Modularity of Discrete Regulatory Networks

A biological regulatory network can be modeled as a discrete function f that contains all available information on network component interactions. From f we can derive a graph representation of the network structure as well as of the dynamics of the system. In this paper we introduce a method to identify modules of the network that allow us to construct the behavior of f from the dynamics of the modules. Here, it proves useful to distinguish between dynamical and structural modules, and to define network modules combining aspects of both. As a key concept we establish the notion of symbolic steady state, which basically represents a set of states where the behavior of f is in some sense predictable, and which gives rise to suitable network modules. We apply the method to a regulatory network involved in T helper cell differentiation.
An oscillator-based true random number generator with process and temperature tolerance

This paper presents an oscillator-based true random number generator (TRNG) that automatically adjusts the duty cycle of a fast oscillator to 50 %, and generates unbiased random numbers tolerating process variation and dynamic temperature fluctuation. Measurement results with 65nm test chips show that the proposed TRNG adjusted the probability of `1' to within 50 ± 0.07 % in five chips in the temperature range of 0 °C to 75 °C. Consequently, the proposed TRNG passed the NIST and DIEHARD tests at 7.5 Mbps with 6,670 μm2 area.
Genome Analysis of Phage JS98 Defines a Fourth Major Subgroup of T4-Like Phages in Escherichia coli

ABSTRACT Numerous T4-like Escherichia coli phages were isolated from human stool and environmental wastewater samples in Bangladesh and Switzerland. The sequences of the major head gene (g23) revealed that these coliphages could be placed into four subgroups, represented by the phages T4, RB69, RB49, and JS98. Thus, JS98 defines a new major subgroup of E. coli T4-like phages. We conducted an analysis of the 169-kb JS98 genome sequence. Overall, 198 of the 266 JS98 open reading frames (ORFs) shared amino acid sequence identity with the reference T4 phage, 41 shared identity with other T4-like phages, and 27 ORFs lacked any database matches. Genes on the plus strand encoded virion proteins, which showed moderate to high sequence identity with T4 proteins. The right genome half of JS98 showed a higher degree of sequence conservation with T4 and RB69, even for the nonstructural genes, than did the left genome half, containing exclusively nonstructural genes. Most of the JS98-specific genes were found in the left genome half. Two came as a hypervariability cluster, but most represented isolated genes, suggesting that they were acquired separately in multiple acquisition events. No evidence for DNA exchange between JS98 phage and the E. coli host genome or coliphages other than T4 was observed. No undesired genes which could compromise its medical use were detected in the JS98 genome sequence.
A new hybrid modular multilevel converter with increased output voltage levels

The modular multilevel converter (MMC) has become the most promising converter technology for high power applications. However, to get more number of levels in the output voltage, a conventional MMC requires large number of submodules. The main technical challenges of an MMC, with a large number of submodules, are the requirement of large number of semiconductor switches, submodule capacitors and measurement of submodules capacitor voltages. This makes MMC bulky and increases control complexity. This paper presents a new hybrid MMC, which uses half bridge submodules (HBSMs) and auxiliary full bridge submodules (FBSMs) in each arm of the converter. Compared with the conventional MMC, the proposed topology uses fewer submodules to get the same number of output voltage levels. This reduces the footprint and control complexity in the proposed MMC. A modified selecting and sorting algorithm for ensuring capacitor voltage balancing of HBSMs and auxiliary FBSMs is developed. The performance of the proposed converter and capacitor voltage control technique for standalone model is evaluated by using time domain simulation studies in PSCAD/EMTDC. The simulation results for standalone operation and HVDC applications demonstrate feasibility and validity of the proposed hybrid MMC. Experimental studies are also presented to further demonstrate the effectiveness of the proposed converter and control techniques.
γ‐Aminobutyric Acid Greatly Increases the In Vivo Extracellular Taurine in the Rat Hippocampus

Abstract: The effects of γ‐aminobutyric acid (GABA) on the extracellular levels of taurine and on excitability in the dentate gyrus were studied in anesthetized rats by the dialytrode technique. The dentate gyrus was perfused by means of a dialytrode with Krebs‐Ringer‐bicarbonate or GAB A solutions. Amino acid contents in perfusates and dentate field potentials evoked by electrical stimulation of the perforant pathway were evaluated. GAB A drastically elevated the levels of extracellular taurine in a dose‐dependent manner, decreasing the amplitude of the population spike. This result indicates that GABA stimulates taurine release, probably by a counter‐transport process. It is suggested that in physiological conditions an increase in extracellular taurine may be produced by synaptically released GABA.
Early Effect of Single-dose Sitagliptin Administration on Gastric Emptying: Crossover Study Using the 13C Breath Test

Background/Aims The gastrointestinal motility effects of endogenous incretin hormones enhanced by dipeptidyl peptidase-IV (DPP-IV) inhibitors have not yet been sufficiently investigated. The aim of this study was to determine whether single pre-prandial sitagliptin, the DPP-IV inhibitor, administration might have an effect on the rate of liquid gastric emptying using the 13C-acetic acid breath test. Methods Ten healthy male volunteers participated in this randomized, two-way crossover study. The subjects fasted for overnight and were randomly assigned to receive 50 mg sitagliptin 2 hours before ingestion of the liquid test meal (200 kcal per 200 mL, containing 100 mg 13C-acetate) or the test meal alone. Under both conditions, breath samples were collected for 150 minutes following the meal. Liquid gastric emptying was estimated by the values of the following parameters: the time required for 50% emptying of the labeled meal (T1/2), the analog to the scintigraphy lag time for 10% emptying of the labeled meal (Tlag), the gastric emptying coefficient and the regression-estimated constants (β and κ), calculated by using the 13CO2 breath excretion curve using the conventional formulae. The parameters between the 2 test conditions were compared statistically. Results No significant differences in the calculated parameters, including T1/2, Tlag, gastric emptying coefficient or β and κ, were observed between the 2 test conditions. Conclusions The present study revealed that single-dose sitagliptin intake had no significant influence on the rate of liquid gastric emptying in asymptomatic volunteers.
Adaptation of a Couple-Based HIV Intervention for Methamphetamine-Involved African American Men who have Sex with Men

In the U.S., incidence of HIV infection among men who have sex with men (MSM) has steadily increased since the 1990s. This points to a need for innovation to address both emerging trends as well as longer-standing disparities in HIV risk and transmission among MSM, such as the elevated rates of HIV/STIs among African American MSM and methamphetamine users. While couple-based sexual risk reduction interventions are a promising avenue to reduce HIV/STI transmission, prior research has been almost exclusively with heterosexual couples. We sought to adapt an existing, evidence-based intervention—originally developed and tested with heterosexual couples—for a new target population consisting of African American MSM in a longer-term same-sex relationship where at least one partner uses methamphetamine. The adaptation process primarily drew from data obtained from a series of focus groups with 8 couples from the target population. Attention is given to the methods used to overcome challenges faced in this adaptation process: limited time, a lead investigator who is phenotypically different from the target population, a dearth of descriptive information on the experiences and worldviews among the target population, and a concomitant lack of topical experts. We also describe a visualization tool used to ensure that the adaptation process promotes and maintains adherence to the theory that guides the intervention and behavior change. The process culminated with an intervention adapted for the new target population as well as preliminary indications that a couple-based sexual-risk reduction intervention for African American, methamphetamine-involved male couples is feasible and attractive.
Iterative Soft-Kalman Channel Estimation for Fast Time-Varying MIMO-OFDM Channels

This letter addresses the problem of channel estimation in fast time-varying frequency selective channels. Considering orthogonal frequency division multiplexing in a multiple-input multiple-output system, we perform soft-Kalman filtering for channel estimation in conjunction with soft-interference canceling at the receiver to reduce the inter-carrier interference. We also propose two simplified implementations of the soft-Kalman filter for the case of constant-modulus signal constellations that allow considerable reductions in the receiver computational complexity, while performing more or less closely to the exact soft-Kalman estimator, depending on channel conditions. For non-constant-modulus signal constellations, however, the exact formulation of the soft-Kalman filter should be used.
Epidemiological Evidence Linking Tea Consumption to Human Health: A Review

Tea has been widely consumed around the world for thousands of years and drinking tea is a daily habit for people of all ages. Tea is a major source of flavanoids, which have become well known as antioxidants. Tea also contains caffeine and theanine, which have been found to associate with health benefits. Many animal and epidemiological studies have been conducted to investigate the link between tea consumption and human health. However, common questions that arise about tea consumption include: whether all teas are the same, why drinking tea is linked with health benefits, how do the different ways of tea preparation impact on availability of tea components, how much and how long a person should consume tea to obtain health benefits, and whether there is any negative health effect associated with drinking tea. To answer these questions, this paper outlines the tea components and their link to human health, discusses major factors affecting availability of tea components in a tea cup, and reviews the latest epidemiological evidence linking tea consumption to human health.
AClass : An online algorithm for generative classification

We present AClass, a simple, online, parallelizable algorithm for supervised multiclass classification. AClass models each classconditional density as a Chinese restaurant process mixture, and performs approximate inference in this model using a sequential Monte Carlo scheme. AClass combines several strengths of previous approaches to classification that are not typically found in a single algorithm; it supports learning from missing data and yields sensibly regularized nonlinear decision boundaries while remaining computationally efficient. We compare AClass to several standard classification algorithms and show competitive performance.