A library of ab initio Raman spectra for automated identification of 2D materials

Raman spectroscopy is frequently used to identify composition, structure and layer thickness of 2D materials. Here, we describe an efficient first-principles workflow for calculating resonant first-order Raman spectra of solids within third-order perturbation theory employing a localized atomic orbital basis set. The method is used to obtain the Raman spectra of 733 different monolayers selected from the computational 2D materials database (C2DB). We benchmark the computational scheme against available experimental data for 15 known monolayers. Furthermore, we propose an automatic procedure for identifying a material based on an input experimental Raman spectrum and illustrate it for the cases of MoS$_2$ (H-phase) and WTe$_2$ (T$^\prime$-phase). The Raman spectra of all materials at different excitation frequencies and polarization configurations are freely available from the C2DB. Our comprehensive and easily accessible library of \textit{ab initio} Raman spectra should be valuable for both theoreticians and experimentalists in the field of 2D materialsComment: 17 pages, 7 figure

Visualizing particle networks in granular media by in situ X-ray computed tomography

In this contribution, cylindrical samples consisting of monodisperse soft (rubber) and stiff (glass) particles are pre-stressed under uniaxial compression. Acoustic P-waves at ultrasound frequencies are superimposed into prepared samples with different soft-stiff volume fractions. Earlier investigations showed the importance of particles networks, i.e. force chains, in controlling the effective mechanical properties of particulate systems. Measured P-wave modulus showed a significant decline while more soft particles are added due to a change in microstructure. However, for small contents of soft particles, it could be observed that the P-wave modulus is increasing. For the understanding of such kinds of effects, detailed insight into the microstructure of the system is required. To gain this information and link it to the effective properties, we made use of high-resolution micro X-ray Computed Tomography (micro-XRCT) imaging and combined it with the classical stiffness characterization. Both performed in situ meaning inside the laboratory-based XRCT scanner. With micro-XRCT imaging, the granular microstructure can be visualized in 3d and characterized subsequently. By post-processing of the data, the individual grains of the particulate systems could be uniquely identified. Finally, the contact network of the packings which connects the center of particles was established to demonstrate the network transition from stiff- to soft-dominated regimes. This has allowed for unprecedented observations and a renewed understanding of particulate systems. It has been demonstrated that micro-XRCT scans of particles packings can be analyzed and compared in 3d to gain extensive information on the scale of the single particles. Here, the in situ setup and workflow from the start of acquiring images in situ till the post-processing of the image data is explained and demonstrated by selected results.Comment: 17 pages, 10 figures, submitted to Survey for Applied Mathematics and Mechanics (GAMM Mitteilungen

Short communication: Growth performance, nutrient digestibility and blood parameters of fattening lambs fed diet replacing corn with orange pulp

The objective of the present study was to evaluate the effect of replacing corn with orange pulp (OP) on growth performance, rumen fermentation, nutrient digestibility and blood parameters of fattening lambs. Twenty male lambs were placed in individual pens and fed with four levels of replacement of corn by OP (0, 33, 66, 100%) during 60 days. Average daily gain (ADG) showed a quadratic effect (p<0.007) with the increasing levels of replacement. Inclusion of 33 and 66% of OP in the diet significantly increased dry matter intake (DMI) compared to control group (p<0.01). Ruminal ammonia-N concentration showed a linear decrease (p<0.002). Ruminal fluid pH increased linearly with the increasing replacement of corn by OP (p<0.001). Acetate concentration showed a linear increase (p<0.001). Plasma total protein showed a linear increase (p<0.002). Organic matter, crude protein and neutral detergent fiber showed a quadratic effect with the level of replacement. The results of the present study showed that replacement of corn by OP improves DMI of fattening lambs, leading to an enhancement in ADG at the replacement level of 40.3%. Also, total replacement of corn by OP did not have any adverse effect on growth performance, rumen fermentation, nutrient digestibility and blood parameters

Tracking moving targets in wireless sensor networks using extended diffusion strategies of distributed Kalman filter

Using wireless sensor networks to track the position of a moving object in a 3-D spatial model requires precise information of location and speed of the object, which in turn demands for accuracy in state estimation of distributed Kalman filter. In view of reducing the impacts of noise in the dynamic linear system and achieve optimized state estimate, the current study proposes extended strategies of Kalman filter diffusion based on distributed Kalman filter. Through the proposed strategies, each node communicates merely with its neighbor nodes. The data aggregation is done in a set of neighborhood using instructions of recursive Kalman filter iterations with specific weights. The proposed algorithms provide precise state estimates in a moment as global state estimates using various updates at each step. As a simulation study, we applied the algorithms in a network to track the position and speed of a projectile and compared the results with real world circumstances, using the concept of transient mean square deviations of network as a cost function. The results report improvements over the conventional methods in terms of mean square errors

Distribution of Maximal Luminosity of Galaxies in the Sloan Digital Sky Survey

Extreme value statistics (EVS) is applied to the distribution of galaxy luminosities in the Sloan Digital Sky Survey (SDSS). We analyze the DR8 Main Galaxy Sample (MGS), as well as the Luminous Red Galaxies (LRG). Maximal luminosities are sampled from batches consisting of elongated pencil beams in the radial direction of sight. For the MGS, results suggest a small and positive tail index $\xi$, effectively ruling out the possibility of having a finite maximum cutoff luminosity, and implying that the luminosity distribution function may decay as a power law at the high luminosity end. Assuming, however, $\xi=0$, a non-parametric comparison of the maximal luminosities with the Fisher-Tippett-Gumbel distribution (limit distribution for variables distributed by the Schechter fit) indicates a good agreement provided uncertainties arising both from the finite batch size and from the batch size distribution are accounted for. For a volume limited sample of LRGs, results show that they can be described as being the extremes of a luminosity distribution with an exponentially decaying tail, provided the uncertainties related to batch-size distribution are taken care of

Prevalence of Cryptosporidium spp. infection in renal transplant and hemodialysis patients

Transplanted and hemodialysis patients are frequently affected by parasitic diseases such as cryptosporidiosis. Cryptosporidium is a parasite causing self-limited diarrhea and enteritis in healthy individuals. The presence of Cryptosporidium infection was studied in three groups including 87 renal transplant patients, 103 hemodialysis patients, and 60 healthy individuals as the control group. Two stool specimens were obtained from each case. The specimens were concentrated by the formalin-ether method and two smears were prepared from each. The smears were stained by modified acid-fast method and were observed under a light microscope. Ten (11.5) renal transplant and 4 (3.88) hemodialysis patients were positive for Cryptosporidium infection. No positive results were obtained in the control group. The results showed a statistically significant difference between renal transplant and control groups (P=0.02), but the difference between hemodialysis and control groups was not significant (P=0.2). The results also showed that the rate of Cryptosporidium infection in renal transplant patients was much higher than hemodialysis patients. The susceptibility of renal transplant patients to Cryptosporidium infection is much more than other studied groups and this could be due to immunosuppressive therapy in these patients

Does Infrastructure Investment Lead to Economic Growth?

This chapter examines the relationship between infrastructure investment and economic growth in Central Asian countries. Using quarterly data from 1990 to 2018 and employing the Autoregressive Distributed Lagged Approach to cointegration, the study finds: 1) there is a robust long-run relationship that runs from infrastructure investment to economic growth in the case of Kazakhstan, Tajikistan, and Uzbekistan; 2) in the case of the Kyrgyz Republic, economic growth drives infrastructure investment; 3) there is a bi-directional relationship between infrastructure investment and economic growth in Uzbekistan; and 4) in the short run, infrastructure investment leads to a reduction in economic growth in Tajikistan

Synthesis of Interleaved, Unipolar, Switched Capacitor DC-DC Converters

Switched Capacitor (SC) DC-DC converters are showing great potential for new applications such as data-centres, electric vehicles and power transmission. Many SC topologies have been synthesised on an ad-hoc basis, although new computer methods are being introduced to formalise this process. This paper presents a general synthesis technique that can be incorporated into a computer algorithm to assist with the development of new SC circuits. The technique is based on interleaving SC converter circuits, where two unipolar converters are connected in parallel, and each leg is driven by separate, complementary gate signals. By applying this method to the traditional Ladder SC converter, a topology termed as a Simplified Interleaved Ladder (SIL) converter, is synthesised and tested using a hardware prototype. The resonant implementation of the SIL converter has desirable features for MV/LV applications when compared with other existing SC circuits