SURFACE LAYER THICKNESS AND ANISOTROPY OF THE SURFACE ENERGY OF CUBIC RUTHENIUM CRYSTALS

В работе рассмотрены вопросы анизотропии поверхностного слоя и анизотропии поверхностной энергии кубических кристаллов рутения. В основе этого рассмотрения лежит эмпирическая модель атомарно-гладких кристаллов, толщина поверхностного слоя которых зависит от одного фундаментального параметра -атомного объема элемента. Расчеты кристаллов рутения показали, что толщина поверхностного слоя кристаллов рутения во всех направлениях не превышает d (I) < 10 нм и они представляют собой наноструктуру. Кристаллы рутенийалюминий, рутенийгафний, рутенийтитан, рутенийцирконий имеют ơ > 3 Дж/м в направлении (100) . Нами рассмотрена задача о диффузии газа в нанометровой пластине рутения. В отличие от классической задачи в полученном уравнении появляется логарифмический член. Это приводит к расходимости в начале координат. Поэтому граничные условия нужно задавать не при x = 0, а при x = d (0) - длине де Бройлевской волны электронов. Только в этом случае имеют смысл классические уравнения диффузии. Существенно также, что, согласно полученному уравнению, диффузии нанопластины зависит как от материала пластины через коэффициент диффузии массивного образца, так и от размерного фактора. В классическом случае такой зависимости нет. Для описания фазовых переходов в наноструктурах предложены различные модели, среди которых можно отметить метод среднего поля Ландау, в котором используется параметр порядка. Мы воспользуемся теорией Ландау, заменяя температуру T на координату h . The paper deals with the anisotropy of the surface layer and the anisotropy of the free surface energy of cubic ruthenium crystals. This consideration is based on an empirical model of atomically smooth crystals, the thickness of the surface layer of which depends on single fundamental parameter - the atomic volume of an element. Calculations of ruthenium crystals showed that the thickness of the surface layer of ruthenium crystals in all directions does not exceed d(I)< 10 nm and they represent a nanostructure. Crystals of ruthenium aluminum, ruthenium hafnium, ruthenium titanium, ruthenium zirconium have ơ > 3 J/m in the (100) direction. We have considered the problem of gas diffusion in a nanometer ruthenium plate. In contrast to the classical problem, a logarithmic term appears in the resulting equation. This leads to divergence at the origin. Therefore, the boundary conditions must be specified not at x = 0, but at x = d (0) - the de Broglie wavelength of electrons. Only in this case the classical diffusion equations are meaningful. It is also important that, according to the obtained equation, the diffusion of the nanoplate depends both on the material of the plate through the diffusion coefficient of the bulk sample and on the size factor. In the classical case, there is no such dependence. Various models have been proposed to describe phase transitions in nanostructures, among which we can mention the Landau mean field method, in which the order parameter is used. We will use Landau's theory, replacing the temperature T with the coordinate h.

Levelized Cost Based Economic Assessment of Waste-to-Energy Conversion Technologies in Pakistan

Regarding the bridging of the existing gap around the economic assessment of waste-to-energy (WTE) conversion technologies in Pakistan, this study performs a techno-economic assessment of energy generation through both the thermal and biochemical processes. The levelized cost of electricity (LCOE) serves as the fundamental parameter for analyzing the economic viability of these processes and their comparison with other energy generation processes. Based on the results, essential components of a bioenergy supply chain have been identified, through which the levelized cost can be lowered significantly. Furthermore, it has been defined as: What should be the role of key stakeholders for mobilizing the finance towards the bioenergy infrastructure development in Pakistan?

Prediction of Uniaxial Compression Strength of Limestone Based on the Point Load Strength and SVM Model

Uniaxial compression strength (UCS) is a fundamental parameter to carry out geotechnical engineering design and construction. It is simple and efficient to predict UCS using point load strength (PLS) at engineering sites. However, the high dispersion of rock strength limits the accuracy of traditional fitting prediction methods. In order to improve the UCS prediction accuracy, 30 sets of regular cylindrical specimen tests between PLS and UCS are conducted on limestone mines. The correlation relationship between PLS and UCS is found by using four basic fitting functions. Then, a prediction model is established by using SVM algorithm. Multiple training test data are used to achieve high-precision prediction of UCS and the results show it is less different from the actual values. Especially, the R2 coefficient reached 0.98. The SVM model prediction performance is significantly better than the traditional fitting function. The constructed SVM model in this study can accurately predict the UCS using the PLS obtained in the field, which has a great significance to the rock stability judgment in the actual construction environment.

Copper and Trace Elements in Gallbladder form Patients with Wilson’s Disease Imaged and Determined by Synchrotron X-ray Fluorescence

Investigations about suspected tissue alterations and the role of gallbladder in Wilson’s disease (WD)—an inherited genetic disease with impaired copper metabolism—are rare. Therefore, tissue from patients with genetically characterised WD was investigated by microscopic synchrotron X-ray fluorescence (µSRXRF). For two-dimensional imaging and quantification of elements, X-ray spectra were peak-fitted, and the net peak intensities were normalised to the intensity of the incoming monochromatic beam intensity. Concentrations were calculated by fundamental parameter-based program quant and external standardisation. Copper (Cu), zinc (Zn) and iron (Fe) along with sulphur (S) and phosphorus (P) mappings could be demonstrated in a near histological resolution. All these elements were increased compared to gallbladder tissue from controls. Cu and Zn and Fe in WD-GB were mostly found to be enhanced in the epithelium. We documented a significant linear relationship with Cu, Zn and sulphur. Concentrations of Cu/Zn were roughly 1:1 while S/Cu was about 100:1, depending on the selected areas for investigation. The significant linear relationship with Cu, Zn and sulphur let us assume that metallothioneins, which are sulphur-rich proteins, are increased too. Our data let us suggest that the WD gallbladder is the first in the gastrointestinal tract to reabsorb metals to prevent oxidative damage caused by metal toxicity.

Mapping Relation of Leakage Currents of Polluted Insulators and Discharge Arc Area

A fundamental parameter of polluted insulator online monitoring is the leakage current, which has already been shown to be well-related to the pollution discharge of insulators. In this article, in an effort to quantitatively reflect the discharge intensity and the discharge status by the leakage current, we carried out an experimental study on artificial pollution discharge of insulators. A high-speed photographic apparatus was utilized to capture the entire process of local arcs on a porcelain insulator surface, including the arc generation, the arc development, and the flashover, for which the associated leakage current of insulators was synchronously digitized. A comparative analysis of the relation between the two-dimensional discharge image and the leakage current waveform in the process of arc generation and development shows that if the arc area on the insulator surface is relatively small and the leakage current passes through zero, the arc might completely become extinct, whereas this phenomena will not occur if the arc area is larger. In addition, the amplitude of the discharge arc area is found to be roughly proportional to the square of leakage current over the range of leakage current amplitude from 0 to 150 mA. Our results can provide an important guidance for judgment of the discharge status and the discharge intensity on insulator surfaces using the leakage current of insulators.

Estimation of Boreal Forest Growing Stock Volume in Russia from Sentinel-2 MSI and Land Cover Classification

Growing stock volume (GSV) is a fundamental parameter of forests, closely related to the above-ground biomass and hence to carbon storage. Estimation of GSV at regional to global scales depends on the use of satellite remote sensing data, although accuracies are generally lower over the sparse boreal forest. This is especially true of boreal forest in Russia, for which knowledge of GSV is currently poor despite its global importance. Here we develop a new empirical method in which the primary remote sensing data source is a single summer Sentinel-2 MSI image, augmented by land-cover classification based on the same MSI image trained using MODIS-derived data. In our work the method is calibrated and validated using an extensive set of field measurements from two contrasting regions of the Russian arctic. Results show that GSV can be estimated with an RMS uncertainty of approximately 35–55%, comparable to other spaceborne estimates of low-GSV forest areas, with 70% spatial correspondence between our GSV maps and existing products derived from MODIS data. Our empirical approach requires somewhat laborious data collection when used for upscaling from field data, but could also be used to downscale global data.

On solving classes of positive-definite quantum linear systems with quadratically improved runtime in the condition number

Quantum algorithms for solving the Quantum Linear System (QLS) problem are among the most investigated quantum algorithms of recent times, with potential applications including the solution of computationally intractable differential equations and speed-ups in machine learning. A fundamental parameter governing the efficiency of QLS solvers is κ, the condition number of the coefficient matrix A, as it has been known since the inception of the QLS problem that for worst-case instances the runtime scales at least linearly in κ [Harrow, Hassidim and Lloyd, PRL 103, 150502 (2009)]. However, for the case of positive-definite matrices classical algorithms can solve linear systems with a runtime scaling as κ, a quadratic improvement compared to the the indefinite case. It is then natural to ask whether QLS solvers may hold an analogous improvement. In this work we answer the question in the negative, showing that solving a QLS entails a runtime linear in κ also when A is positive definite. We then identify broad classes of positive-definite QLS where this lower bound can be circumvented and present two new quantum algorithms featuring a quadratic speed-up in κ: the first is based on efficiently implementing a matrix-block-encoding of A−1, the second constructs a decomposition of the form A=LL† to precondition the system. These methods are widely applicable and both allow to efficiently solve BQP-complete problems.

The Role of the Bandwidth-Duration Product WT in the Detectability of Diotic Signals

<p>The bandwidth-duration product, WT , is a fundamental parameter in most theories of aural amplitude discrimination of Gaussian noise. These theories predict that detectability is dependent on WT , but not on the individual values of bandwidth and duration. Due to the acoustical uncertainty principle, it is impossible to completely specify an acoustic waveform with both finite duration and finite bandwidth. An observer must decide how best to trade-off information in the time domain with information in the frequency domain. As Licklider (1963) states, "The nature of [the ear's] solution to the time-frequency problem is, in fact, one of the central problems in the psychology of hearing."This problem is still unresolved, primarily due to observer inconsistency in experiments, which degrades performance making it difficult to compare models. The aim was to compare human observers' ability to trade bandwidth and duration, with simulated and theoretical observers. Human observers participated in a parametric study where the bandwidth and duration of 500 Hz noise waveforms was systematically varied for the same bandwidth-duration products (WT = 1, 2, and 4, where W varied over 2.5-160 Hz, and T varied over 400-6.25 ms, in octave steps). If observers can trade bandwidth and duration, detectability should be constant for the same WT . The observers replicated the experiments six times so that group operating characteristic (GOC) analysis could be used to reduce the effects of their inconsistent decision making. Asymptotic errorless performance was estimated by extrapolating results from the GOC analysis, as a function of replications added. Three simulated ideal observers: the energy, envelope, and full-linear (band-pass filter, full-wave rectifier, and true integrator) detectors were compared with each other, with mathematical theory and with human observers. Asymptotic detectability relative to the full-linear detector indicates that human observers best detect signals with a bandwidth of 40-80 Hz and a duration of 50-100 ms, and that other values are traded off in approximately concentric ellipses of equal detectability. Human detectability of Gaussian noise was best modelled by the full-linear detector using a non-optimal filter. Comparing psychometric functions for this detector with human data shows many striking similarities, indicating that human observers can sometimes perform as well as an ideal observer, once their inconsistency is minimised. These results indicate that the human hearing system can trade bandwidth and duration of signals, but not optimally. This accounts for many of the disparate estimates of the critical band, rectifier, and temporal integrator, found in the literature, because (a) the critical band is adjustable, but has a minimum of 40-50 Hz, (b) the rectifier is linear, rather than square-law, and (c) the temporal integrator is either true or leaky with a very long time constant.</p>

The Role of the Bandwidth-Duration Product WT in the Detectability of Diotic Signals

<p>The bandwidth-duration product, WT , is a fundamental parameter in most theories of aural amplitude discrimination of Gaussian noise. These theories predict that detectability is dependent on WT , but not on the individual values of bandwidth and duration. Due to the acoustical uncertainty principle, it is impossible to completely specify an acoustic waveform with both finite duration and finite bandwidth. An observer must decide how best to trade-off information in the time domain with information in the frequency domain. As Licklider (1963) states, "The nature of [the ear's] solution to the time-frequency problem is, in fact, one of the central problems in the psychology of hearing."This problem is still unresolved, primarily due to observer inconsistency in experiments, which degrades performance making it difficult to compare models. The aim was to compare human observers' ability to trade bandwidth and duration, with simulated and theoretical observers. Human observers participated in a parametric study where the bandwidth and duration of 500 Hz noise waveforms was systematically varied for the same bandwidth-duration products (WT = 1, 2, and 4, where W varied over 2.5-160 Hz, and T varied over 400-6.25 ms, in octave steps). If observers can trade bandwidth and duration, detectability should be constant for the same WT . The observers replicated the experiments six times so that group operating characteristic (GOC) analysis could be used to reduce the effects of their inconsistent decision making. Asymptotic errorless performance was estimated by extrapolating results from the GOC analysis, as a function of replications added. Three simulated ideal observers: the energy, envelope, and full-linear (band-pass filter, full-wave rectifier, and true integrator) detectors were compared with each other, with mathematical theory and with human observers. Asymptotic detectability relative to the full-linear detector indicates that human observers best detect signals with a bandwidth of 40-80 Hz and a duration of 50-100 ms, and that other values are traded off in approximately concentric ellipses of equal detectability. Human detectability of Gaussian noise was best modelled by the full-linear detector using a non-optimal filter. Comparing psychometric functions for this detector with human data shows many striking similarities, indicating that human observers can sometimes perform as well as an ideal observer, once their inconsistency is minimised. These results indicate that the human hearing system can trade bandwidth and duration of signals, but not optimally. This accounts for many of the disparate estimates of the critical band, rectifier, and temporal integrator, found in the literature, because (a) the critical band is adjustable, but has a minimum of 40-50 Hz, (b) the rectifier is linear, rather than square-law, and (c) the temporal integrator is either true or leaky with a very long time constant.</p>

Analysis of predictors of mortality after surgical and non-surgical management in proximal humerus fractures

Background Proximal humerus fractures are one of the main osteoporotic fractures. Choosing between conservative or surgical treatment is a controversial topic in the literature, as is the functional impact. The main aim of our study was to analyse whether patient comorbidities should influence the final therapeutic decision for these fractures. Material and methods We collected data from 638 patients with proximal humerus fractures. The main variable collected was exitus. We also collected the following data: age, gender, type of fracture, laterality, type of treatment, production mechanism, comorbidities and the Charlson comorbidity index (CCI) for each patient. The therapeutic indication used the criteria established by the Upper Limb Unit in our centre. We performed chi-square tests, Fischer’s exact tests and Student’s t-tests to compare the variables. We used the Kaplan–Meier method to analyse both the overall and disease-specific survival rates. We employed the Cox regression model to analyse factors associated with mortality. Results Patients with a CCI greater than 5 showed greater mortality (HR = 3.83; p < 0.001) than those with a CCI lower than 5. Within the patients who underwent surgery, those with a CCI higher than 5 had an increased mortality rate (HR = 22.6; p < 0.001) compared with those with a CCI lower than 5. Within the patients who received conservative treatment, those with a CCI over 5 showed greater mortality (HR = 3.64; p < 0.001) than those with a CCI under 5. Conclusions Patients with proximal humerus fractures and associated comorbidities (CCI > 5) presented higher mortality than healthier patients. This mortality risk was greater in patients with comorbidities if surgical treatment was indicated rather than conservative treatment. Patient’s comorbidities should be a fundamental parameter when planning the therapeutic strategy. Level of evidence Level 3.