bluuebunny/crossref_metadata_2025 huggingface dataset:
Ringing of White Storks Ciconia ciconia in NE Slovenia during the 1984–2013 period
Authors: Bračko Franc
Published: March 2017

In a period of 30 years (1984-2013), 1,535 White Stork pulli were ringed on nest and 1,226 nests examined in NE Slovenia. The ringing was implemented in the regions of Dravsko polje, Slovenske gorice and Pomurje. In each season, from 9 to 85 nests were examined, the great majority of them built on overhead powerline pylons. On average, 51.16 pulli or 16.66% were ringed and 40.86 or 18.91% nests visited compared to the census of fledged pulli and inventoried nests in 1999 in NE Slovenia. A total of 71 finds or 4.6% were registered and 37 rings or 52% finds read. There were 26 (36.62%) local recoveries, while in foreign countries 34 (47.88%) recoveries of Slovenian-ringed storks were made. Two of our recoveries were registered abroad prior to 1984. There were 11 (15.49%) foreign recoveries. Local recoveries (n = 26) indicate breeding relationship (mixing) between the eastern and southern Slovenian breeding populations. The longest distance of breeding was 115 km in a beeline, the shortest 62 km (n = 4). Other 12 local recoveries at 1 to 38 km from the place of hatching concerns the native NE breeding area. Young sexually mature storks search for new breeding sites only in their fourth year of age. No ringed stork returned to the native nest as a young breeder. The oldest was 14 years old. Some of them breed in the wider area of the Pannonian Plain outside Slovenia, e.g. 3 in Austria, 2 in Serbia and 1 in Croatia. One of them bred in Slovakia 463 km away. In view of the presented recoveries it has been ascertained that the storks from NE Slovenia migrate across the Pannonian Plain, the Balkans and Asia Minor, down to the South African Republic of 8,923 km in a beeline (4 recoveries), using the eastern migration route. The western migration route was not ascertained. The majority of recoveries originated from the autumn migration period, with only one recovery known from the spring migration period. No less than 23 ringed storks, particularly young ones, were killed on migration owing to collisions with overhead power lines, which indicates inappropriate system of overhead power lines construction all over Europe.
Population size of the Common Quail Coturnix coturnix at Ljubljansko barje decreased in the last twenty years by half, perhaps even (much?) more
Authors: Tome Davorin , Vrezec Al , Ambrožič Špela , Kapla Andrej
Published: March 2017

In 2015, we used the same method as in the 1989-1996 period to count calling males of the Common Quail Coturnix coturnix in selected 1x1 km squares of Ljubljansko barje (central Slovenia). We counted 39 males, which is 87% less compared to the survey 20 years ago. Quails were found in 56% fewer squares. Since Quail populations are known to fluctuate greatly between years, we think that the most realistic long-term estimate for population decline would be somewhere between 50 to 90%. We detected that within only one week males stopped calling in some squares, while in others they began calling although they had not been detected there before, indicating possible relocations. This dynamics should be considered when designing a population monitoring protocol for the Quail.
An Analysis of the Retention of a Diamond Particle in a Metallic Matrix after Hot Pressing
Authors: Borowiecka-Jamrozek J. , Lachowski J.
Published: March 2017

This paper deals with computer modelling of the retention of a synthetic diamond particle in a metallic matrix produced by powder metallurgy. The analyzed sintered powders can be used as matrices for diamond impregnated tools. First, the behaviour of sintered cobalt powder was analyzed. The model of a diamond particle embedded in a metallic matrix was created using Abaqus software. The preliminary analysis was performed to determine the mechanical parameters that are independent of the shape of the crystal. The calculation results were compared with the experimental data. Next, sintered specimens obtained from two commercially available powder mixtures were studied. The aim of the investigations was to determine the influence of the mechanical and thermal parameters of the matrix materials on their retentive properties. The analysis indicated the mechanical parameters that are responsible for the retention of diamond particles in a matrix. These mechanical variables have been: the elastic energy of particle, the elastic energy of matrix and the radius of plastic zone around particle.
Influence of the Matrix Grain Size on the Apparent Density and Bending Strength of Sand Cores
Authors: Dańko R.
Published: March 2017

The results of investigations of the influence of the matrix grain sizes on properties of cores made by the blowing method are presented in the hereby paper. Five kinds of matrices, differing in grain size compositions, determined by the laser diffraction method in the Analysette 22NanoTec device, were applied in investigations. Individual kinds of matrices were used for making core sands in the Cordis technology. From these sands the shaped elements, for determining the apparent density of compacted sands and their bending strength, were made by the blowing method. The shaped elements (cores) were made at shooting pressures being 3, 4 and 5 atn. The bending strength of samples were determined directly after their preparation and after the storing time of 1 hour.
The Analysis of Foundry Engineering of Copper Alloys Based on the Research of a Metallurgist Settlement in Szczepidło
Authors: Garbacz-Klempka A. , Makarowicz P. , Tokarski T.
Published: March 2017

The article presents chosen aspects of foundry engineering of the settlement dwellers, including the archaeometric characteristics and metal science analysis of the artefacts, as well as an attempted reconstruction of the production organization. Discovered in Szczepidło (Greater Poland), the foundry workshop is unique in Central European Bronze Age.

This workshop foundry operated roughly XIV-XII Century BC. Its production is evidenced by the presence of markers of the whole production cycle: semi-finished and finished products, production waste, fragments of crucibles and casting ladles with traces of usage, and tools. On this basis, the alloys and foundry technologies used have been described.

The analysis of foundry technology of copper alloys in the settlement area was carried out by observing the surface and structure of the products, semi-finished artefacts and fragments of crucibles by applying optical microscopy (OM), confocal microscopy (CLSM) and Xray radiography (RT). The investigations of compositions were made by means of the energy dispersive X-ray fluorescence spectroscopy (ED-XRF) and scanning electron microscopy (SEM) coupled with an energy dispersive X-ray analysis system (EDS).
Validation Tests of Prediction Modules of Shrinkage Defects in Cast Iron Sample
Authors: Hajkowski J. , Roquet P. , Khamashta M. , Codina E. , Ignaszak Z.
Published: March 2017

The paper presents the results of experimental-simulation tests of expansion-shrinkage phenomena occurring in cast iron castings. The tests were based on the standard test for inspecting the tendency of steel-carbon alloys to create compacted discontinuities of the pipe shrinkage type. The cast alloy was a high-silicone ductile iron of GJS - 600 - 10 grade. The validation regarding correctness of prognoses of the shrinkage defects was applied mostly to the simulation code (system) NovaFlow & Solid CV (NFS CV). The obtained results were referred to the results obtained using the Procast system (macro- and micromodel). The analysis of sensitivity of the modules responsible for predicting the shrinkage discontinuities on selected pre-processing parameters was performed, focusing mostly on critical fractions concerning the feeding flows (mass and capillary) and variation of initial temperature of the alloy in the mould and heat transfer coefficient (HTC) on the casting - chill interface.
Influence of the Hardener Type on the Hardening Process Kinetics of the Selected Self-setting Sands
Authors: Jamrozowicz Ł. , Kolczyk J. , Kaźnica N. , Pyziak Z.
Published: March 2017

Measurements of the hardening process of the selected self-setting sands are presented in the hereby paper. Moulding sands were prepared on the matrix of „Szczakowa” sand of the Sibelco Company. Two resins: phenol-formaldehyde-furfuryl (FF/AF) and urea-formaldehydefurfuryl (MF/AF) were used for making moulding sands. - Methylbenzene-sulphonic acid was applied as a hardener for the moulding sand on FF/AF resin, while paratoluene-sulphonic acid for the moulding sand on MF/AF resin. Both hardeners were used in two concentrations: low - the so-called ‘slow’ hardener and high - ‘fast’ hardener. During investigations, the courses of the hardening process were determined, more accurately changes of the velocity of the ultrasound wave passage through the moulding sand cL = f(t) and changes of the moulding sand hardening degree versus time, Sx = f(t). In addition, the kinetics of the hardening process was determined. Measurements were performed on the research stand for ultrasound investigations.
Nanocomposites Based on Water Glass Matrix as a Foundry Binder: Chosen Physicochemical Properties
Authors: Kmita A. , Roczniak A.
Published: March 2017

The nanocomposites based on water glass matrix were attempted in the study. Nanoparticles of ZnO, Al2O3 or MgO in organic solutions were applied into water glass matrix in the amounts of: 1.5; 3; 4 or 5 mas. %. Wettability of the quartz sad by the nanocomposites based on water glass matrix was determined by testing changes of the wetting angle θ in time τ for the system: quartz - binder in non-stationary state, by means of the device for measuring wetting angles. Wettability measurements were carried out under isothermal conditions at an ambient temperature (20 - 25°C). The modification improves wettability of quartz matrix by water glass, which is effective in improving strength properties of hardened moulding sands. Out of the considered modifiers in colloidal solution of propyl alcohol water glass modified by MgO nanoparticles indicated the smallest values of the equilibrium wetting angle θr. This value was equal app. 11 degrees and was smaller no less than 40 degrees than θr value determined for not modified water glass. Viscosity η of nanocomposites based on water glass matrix was determined from the flow curve, it means from the empirically determined dependence of the shearing stress τ on shear rate γ: τ = f (γ) (1), by means of the rotational rheometer. Measurements were carried out at a constant temperature of 20°C. The modification influences the binder viscosity. This influence is conditioned by: amount of the introduced modifier as well as dimensions and kinds of nanoparticles and organic solvents. The viscosity increase of the modified binder does not negatively influence its functional properties.
The Effect of Si and Mn on Microstructure and Selected Properties of Cr-Ni Stainless Steels
Authors: Kalandyk B. , Zapała R. , Starowicz M.
Published: March 2017

Cast stainless steel of the Cr-Ni duplex type is used, among others, for the cast parts of pumps and valves handling various chemically aggressive media. Therefore, the main problem discussed in this article is the problem of abrasion wear resistance in a mixture of SiC and water and resistance to electrochemical corrosion in a 3% NaCl-H2O solution of selected cast steel grades, i.e. typical duplex cast steel, high silicon and manganese duplex cast steel, and Cr-Ni austenitic cast steel (type AISI 316L). The study shows that the best abrasion wear resistance comparable to Ni-Hart cast iron was obtained in the cast duplex steel, where Ni was partially replaced with Mn and N. This cast steel was also characterized by the highest hardness and matrix microhardness among all the tested cast steel grades. The best resistance to electrochemical corrosion in 3% NaCl-H2O solution showed the cast duplex steel with high content of Cr, Mo and N. The addition of Ni plays rather insignificant role in the improvement of corrosion resistance of the materials tested.
Microstructure of the Bonding Zone Between AZ91 and AlSi17 Formed by Compound Casting
Authors: Mola R. , Bucki T. , Dziadoń A.
Published: March 2017

This paper discusses the joining of AZ91 magnesium alloy with AlSi17 aluminium alloy by compound casting. Molten AZ91 was cast at 650°C onto a solid AlSi17 insert placed in a steel mould under normal atmospheric conditions. Before casting, the mould with the insert inside was heated up to about 370°C. The bonding zone forming between the two alloys because of diffusion had a multiphase structure and a thickness of about 200 μm. The microstructure and composition of the bonding zone were analysed using optical microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. The results indicate that the bonding zone adjacent to the AlSi17 alloy was composed of an Al3Mg2intermetallic phase with not fully consumed primary Si particles, surrounded by a rim of an Mg2Si intermetallic phase and fine Mg2Si particles. The bonding zone near the AZ91 alloy was composed of a eutectic (an Mg17Al12intermetallic phase and a solid solution of Al and Si in Mg). It was also found that the compound casting process slightly affected the AZ91 alloy microstructure; a thin layer adjacent to the bonding zone of the alloy was enriched with aluminium.
Study on Friction and Wear Characteristics of Aluminum Alloy Hydraulic Valve Body and Its Antiwear Mechanism
Authors: Rong Li , Lunjun Chen , Ming Su , Qi Zeng , Yong Liu
Published: March 2017

In order for the working status of the aluminum alloyed hydraulic valve body to be controlled in actual conditions, a new friction and wear design device was designed for the cast iron and aluminum alloyed valve bodies comparison under the same conditions. The results displayed that: (1) The oil leakage of the aluminum alloyed hydraulic valve body was higher than the corresponding oil leakage of the iron body during the initial running stage. Besides during a later running stage, the oil leakage of the aluminum alloyed body was lower than corresponding oil leakage of the iron body; (2) The actual oil leakage of different materials consisted of two parts: the foundation leakage that was the leakage of the valve without wear and wear leakage that was caused by the worn valve body; (3) The aluminum alloyed valve could rely on the dust filling furrow and melting mechanism that led the body surface to retain dynamic balance, resulting in the valve leakage preservation at a low level. The aluminum alloy modified valve body can meet the requirements of hydraulic leakage under pressure, possibly constituting this alloy suitable for hydraulic valve body manufacturing.
Detection of Wood Boring Insects’ Larvae Based on the Acoustic Signal Analysis and the Artificial Intelligence Algorithm
Authors: Bilski Piotr , Bobiński Piotr , Krajewski Adam , Witomski Piotr
Published: March 2017

The paper presents an application of signal processing and computational intelligence methods to detect presence of the wood boring insects larvae in the wooden constructions (such as the furniture of buildings). Such insects are one of the main sources of the degradation in such objects, therefore they should be detected as quickly as possible, before inflicting serious damage. The presented work involved the acoustic monitoring for detecting the presence of the larvae inside pieces of wood. An accelerometer was used to record the sound, further analyzed by a computer algorithm extracting features important for artificial-intelligence (AI) based classification employed to detect the old house borer’s (Hylotrupes bajulus L.) activity. The presented task is difficult, as the sounds made by the larvae are of relatively low amplitude and the background noise caused by people, electrical appliances or other sources may significantly degrade the accuracy of detection. The classification of sounds is needed to separate sources of noise which deteriorate the proper larva detection and should be suppressed if possible. The employed classification was based on features defined in the time domain followed by the support vector machine used as the binary classifier. The results allowed us to assess the effectiveness of the old house borer’s detection by the acoustic analysis enhanced with the AI algorithm.
The Effect of Angle of Attack and Flow Conditions on Turbulent Boundary Layer Noise of Small Wind Turbines
Authors: Afanasieva Nadiia
Published: March 2017

The article aims to solve the problem of noise optimization of small wind turbines. The detailed analysis concentrates on accurate specification and prediction of the turbulent boundary layer noise spectrum of the blade airfoil. The angles of attack prediction for a horizontal axis wind turbine (HAWT) and the estimation based on literature data for a vertical axis one (VAWT), were conducted, and the influence on the noise spectrum was considered. The 1/3-octave sound pressure levels are obtained by semi-empirical model BPM. Resulting contour plots show a fundamental difference in the spectrum of HAWT and VAWT reflecting the two aerodynamic modes of flow that predefine the airfoil self-noise. Comparing the blade elements with a local radius of 0.875 m in the HAWT and VAWT conditions the predicted sound pressure levels are the 78.5 dB and 89.8 dB respectively. In case of the HAWT with predicted local angle of attack ranging from 2.98° to 4.63°, the acoustic spectrum will vary primarily within broadband frequency band 1.74-20 kHz. For the VAWT with the local angle of attack ranging from 4° to 20° the acoustic spectrum varies within low and broadband frequency bands 2 Hz - 20 kHz.
Optimized Driver Placement for Array-Driven Flat-Panel Loudspeakers
Authors: Anderson David A. , Heilemann Michael C. , Bocko Mark F.
Published: March 2017

The recently demonstrated ‘modal crossover network’ method for flat panel loudspeaker tuning employs an array of force drivers to selectively excite one or more panel bending modes from a spectrum of panel bending modes. A regularly spaced grid of drivers is a logical configuration for a two-dimensional driver array, and although this can be effective for exciting multiple panel modes it will not necessarily exhibit strong coupling to all of the modes within a given band of frequencies. In this paper a method is described to find optimal force driver array layouts to enable control of all the panel bending modes within a given frequency band. The optimization is carried out both for dynamic force actuators, treated as point forces, and for piezoelectric patch actuators. The optimized array layouts achieve similar maximum mode coupling efficiencies in comparison with regularly spaced driver arrays; however, in the optimized arrays all of the modes within a specified frequency band may be independently addressed, which is important for achieving a desired loudspeaker frequency response. Experiments on flat panel loudspeakers with optimized force actuator array layouts show that each of the panel modes within a selected frequency band may be addressed independently and that the inter-modal crosstalk is typically −30 dB or less with non-ideal drivers.
Discriminating sediment and clear water over coastal water using GD technique
Authors: Amin Abd Rahman Mat , Ahmad Fadhli , Abdullah Khiruddin
Published: March 2017

Currently two algorithms are being used routinely by the MODIS Atmosphere and Ocean Team in order to distinguish sediment influence and clear water pixels over turbid water area. These two algorithms require complicated computational analyses. In this paper, a simple algorithm based on empirical technique to detect the sediment-influenced pixels over coastal waters is proposed as an alternative to these two algorithms. This study used apparent reflectance acquired from MODIS L1B product. This algorithm is based on the gradient difference of the line connecting the 0.47- and 1.24-μm channels and 0.47- and 0.66-μm channels of a log-log graph of the apparent reflectance values against MODIS wavelengths. Over clear-water areas (deep blue sea), the 0.47-, 0.66- and 1.24-μm channels fitted very well in line with correlation R > 0.99. Over turbid waters, a substantial increase of 0.66 μm in the reflectance leads to a low correlation value. By computing the difference between the gradient of the line connecting 0.47 and 0.66 μm and the gradient of the line connecting 0.47 and 1.24 μm, the threshold to discriminate turbid and shallow coastal waters from clear-water pixels can be obtained. If the gradient difference is greater than 0, the pixels were then marked as sediment-influenced pixels. This proposed algorithm works well for MODIS Terra and Aqua sensor. The comparison of this algorithm with an established algorithm also showed a good agreement.
Methods of trees evaluation with the site-specific effect for microclimate in urban environment: the case of study Nitra (Slovakia)
Authors: Klein Ján , Rózová Zdenka
Published: March 2017

Microclimatic factors in selected vegetation structures have been monitored in a compact historical built-up layout in the Nitra municipality. We have observed relationship between microclimatic factors (air temperature, relative air humidity and surface temperature) and microclimatic environment indices (MEI). MEI were created for selected trees with varied structure on the basis of synthesis of input data (layout samples of canopy layer and urban geometry). They point out the impact of trees and environment on microclimate in an urban environment during hot days. Surface temperature is a significant factor. The model shows that the surface temperature in various structures of trees and varied urban geometry could be identified through MEI. From the microclimatic point of view, the tree cover in the narrow street with 8 MEI has the greatest cooling effect. MEI from 8 to 13 proved the cooling effect with regard to the general diameter of the area. The higher the number of MEI, the lower is the cooling effect of the trees.
Life table estimates of the invasive snail Physa acuta Draparnaud, 1805, occurring in India
Authors: Saha Chilka , Parveen Saida , Chakraborty Joy , Pramanik Soujita , Aditya Gautam
Published: March 2017

The life table characteristics of the invasive snail Physa acuta were assessed in the laboratory using the individuals occurring in a newly colonised area in Burdwan, West Bengal, India. Using the changes in the shell length and the body weight of the snails as surrogate, the population growth of the snails was estimated along with longevity and the fecundity schedule. The cohort of P. acuta lived for a maximum of 22 weeks with a life expectancy (ex) of 7.27 weeks and the age-specific survivorship being 0.825. Increment of the shell length of the snails complied with the von Bertalanffy growth equation, lt = 11.75(1 − exp−0.17(t−0.06)), and the observed and the expected data of the length at time t (lt) did not vary significantly (z score = 0.230; P = 0.818; n=20 pairs). Following attainment of sexual maturity between 28 and 42 days, oviposition continued till 20 weeks time, with 0.1-10 eggs laid by each individual. The eggs present per capsule remained between 01 and 11, whilst the net reproductive rate (R0), intrinsic rate of increase (rm) and the finite rate of increase (λ) were 116.07, 0.1 and 1.11, respectively. The observations are similar to those made earlier on the same species but from African and South American continents. The results of the present observation are pioneer in providing the initial studies about the life history of the invasive snail P. acuta in Indian context. Using the present information as a basis, further studies including long-term population monitoring should be initiated to understand the effects of the invasive snail P. acuta in the freshwater ecosystem of West Bengal, India.
Delineation Lithuanian agricultural land for agro-ecological suitability for farming using soil and terrain criteria
Authors: Jarasiunas Gintaras , Kinderiene Irena , Bašić Ferdo
Published: March 2017

The aim of investigation is to analyse and classify the state of agricultural land affected by naturalbiophysical, that is, soil and terrain-slope, handicaps on its overall agro-ecological suitability for agricultural use. For the classification of land for suitability with respect to sustainable use and efficient protection, the following actual criteria were selected: soil texture, soil drainage and terrainslope. For identifying the relatively homogeneous areas, the Ward hierarchical cluster method was used. According to our estimates, Lithuanian agricultural land with unfavourable soil texture, poorly soil drainage and steep slopes covers an area of 33.59, 4.76 and 1.03% of total agricultural area, respectively. On the basis of functional classification of state of agro-ecological conditions of Lithuania, two orders of suitability (S-suitable, N-not suitable) and five land suitability classes were identified and delineated: S1 (highly suitable) included 10 district municipalities, S2 (moderately suitable) included 12 district municipalities, S3 (marginally suitable) included 15 district municipalities, N1 (currently not suitable) included 10 district municipalities and N2 (permanently not suitable) included 4 district municipalities. S3 occupies the largest (29.80%) share of the Lithuanian territory and N2 the least (5.66%). The land suitable for agriculture means with suitability classes S1, S2 and S3 was found on an area of 2,960,562 ha, which is 81.6% of the total land. In addition, soil texture was the most important factor causing differences in the classes of suitability. On the basis of natural limiting factors from an agronomic and eco-environmental perspective, the optimal sustainable development in agrosphere and a balanced-practical concept of land management and proper land use policy is presented. It is a reasonable base for agroecological regionalisation of Lithuania.
Politisering av feminism. Jämställdhetsfrågor i Aftonbladets partiledardebatt inför riksdagsvalet 2014
Authors: Domeradzka Magdalena
Published: March 2017

This paper investigates a part of the party leaders’ webb-tv debate staged by the Swedish tabloid Aftonbladet on the 1st of September as a part of the election campaign before the elections to the Riksdag, county councils and municipal assemblies that took place on the 14 September 2014. The debate investigated in this paper deals with gender equality questions. The overall aim of this study is to examine what topics the politicians choose to discuss during the debate and what line of argumentation they use. The method used was ideological discourse analysis coupled with classical rhetoric and eristic. The results of the argumentation analysis are set in a broader framework of gender studies and the Swedish political landscape
A synthetic covariance matrix for monitoring by terrestrial laser scanning
Authors: Kauker Stephanie , Schwieger Volker
Published: March 2017

Modelling correlations within laser scanning point clouds can be achieved by using synthetic covariance matrices. These are based on the elementary error model which contains different groups of correlations: non-correlating, functional correlating and stochastic correlating. By applying the elementary error model on terrestrial laser scanning several groups of error sources should be considered: instrumental, atmospheric and object based. This contribution presents calculations for the Leica HDS 7000. The determined variances and the spatial correlations of the points are estimated and discussed. Hereby, the mean standard deviation of the point cloud is up to 0.6 mm and the mean correlation is about 0.6 with respect to 5 m scanning range. The change of these numerical values compared to previous publications as Kauker and Schwieger [17] is mainly caused by the complete consideration of the object related error sources.
Enhancing Navigability: An Algorithm for Constructing Tag Trees
Authors: Chen Chong , Luo Pengcheng
Published: March 2017

Purpose

This study introduces an algorithm to construct tag trees that can be used as a user-friendly navigation tool for knowledge sharing and retrieval by solving two issues of previous studies, i.e. semantic drift and structural skew.

Design/methodology/approach

Inspired by the generality based methods, this study builds tag trees from a co-occurrence tag network and uses the h-degree as a node generality metric. The proposed algorithm is characterized by the following four features: (1) the ancestors should be more representative than the descendants, (2) the semantic meaning along the ancestor-descendant paths needs to be coherent, (3) the children of one parent are collectively exhaustive and mutually exclusive in describing their parent, and (4) tags are roughly evenly distributed to their upper-level parents to avoid structural skew.

Findings

The proposed algorithm has been compared with a well-established solution Heymann Tag Tree (HTT). The experimental results using a social tag dataset showed that the proposed algorithm with its default condition outperformed HTT in precision based on Open Directory Project (ODP) classification. It has been verified that h-degree can be applied as a better node generality metric compared with degree centrality.

Research limitations

A thorough investigation into the evaluation methodology is needed, including user studies and a set of metrics for evaluating semantic coherence and navigation performance.

Practical implications

The algorithm will benefit the use of digital resources by generating a flexible domain knowledge structure that is easy to navigate. It could be used to manage multiple resource collections even without social annotations since tags can be keywords created by authors or experts, as well as automatically extracted from text.

Originality/value

Few previous studies paid attention to the issue of whether the tagging systems are easy to navigate for users. The contributions of this study are twofold: (1) an algorithm was developed to construct tag trees with consideration given to both semantic coherence and structural balance and (2) the effectiveness of a node generality metric, h-degree, was investigated in a tag co-occurrence network.
New Hybrid PAPR Reduction Techniques for OFDM-Based Visible Light Communication Systems
Authors: Freag Haitham , Hassan Emad S. , El-Dolil Sami A. , Dessouky Moawad I.
Published: March 2017

Orthogonal frequency division multiplexing (OFDM) is used with visible light communication (VLC) systems to reduce the effects of inter-symbol interference (ISI) and to achieve communication with high speed of data transmission and huge bandwidth. However, OFDM-based VLC systems suffer from high peak-to-average power ratios (PAPRs). This paper proposes a new hybrid PAPR reduction technique based on signal transformation combined with clipping. The Hadamard transform is used in the proposed technique due to its advantages in reducing the PAPR without affecting the bit error rate (BER) of VLC systems. The optimum clipping threshold at which we can simultaneously reduce the PAPR and improve the BER of VLC systems is also determined. In this paper, we also propose a new OFDM structure based on using discrete cosine transform (DCT) precoding before inverse fast Fourier transform (IFFT) stage to further improve the PAPR reduction capability and BER performance. Several experiments are carried out to test the performance of the proposed technique in terms of complementary cumulative distribution function (CCDF) and the BER. The obtained results show that the proposed technique can simultaneously reduce the PAPR and achieve good BER performance when compared to the original OFDM-based VLC system.
Lattice Boltzmann method used to simulate particle motion in a conduit
Authors: Dolanský Jindřich , Chára Zdeněk , Vlasák Pavel , Kysela Bohuš
Published: March 2017

A three-dimensional numerical simulation of particle motion in a pipe with a rough bed is presented. The simulation based on the Lattice Boltzmann Method (LBM) employs the hybrid diffuse bounce-back approach to model moving boundaries. The bed of the pipe is formed by stationary spherical particles of the same size as the moving particles. Particle movements are induced by gravitational and hydrodynamic forces. To evaluate the hydrodynamic forces, the Momentum Exchange Algorithm is used. The LBM unified computational frame makes it possible to simulate both the particle motion and the fluid flow and to study mutual interactions of the carrier liquid flow and particles and the particle–bed and particle–particle collisions. The trajectories of simulated and experimental particles are compared. The Particle Tracking method is used to track particle motion. The correctness of the applied approach is assessed.
Investigating the impact of surface soil moisture assimilation on state and parameter estimation in SWAT model based on the ensemble Kalman filter in upper Huai River basin
Authors: Liu Yongwei , Wang Wen , Hu Yiming
Published: March 2017

This paper investigates the impact of surface soil moisture assimilation on the estimation of both parameters and states in the Soil and Water Assessment Tool (SWAT) model using the ensemble Kalman filter (EnKF) method in upper Huai River basin. The investigation is carried out through a series of synthetic experiments and real world tests using a merged soil moisture product (ESA CCI SM) developed by the European Space Agency, and considers both the joint state-parameter updating and only state updating schemes. The synthetic experiments show that with joint state-parameter update, the estimation of model parameter SOL_AWC (the available soil water capacity) and model states (the soil moisture in different depths) can be significantly improved by assimilating the surface soil moisture. Meanwhile, the runoff modeling for the whole catchment is also improved. With only state update, the improvement on runoff modeling shows less significance and robustness. Consistent with the synthetic experiments, the assimilation of the ESA CCI SM with joint state-parameter update shows considerable capability in the estimation of SOL_AWC. Both the joint state-parameter update and the only state update scheme could improve the streamflow modeling although the optimal model and observation error parameters for them are quite different. However, due to the high vegetation coverage of the study basin, and the strong spatial mismatch between the satellite and the model simulated soil moisture, it is still challenging to significantly benefit the runoff estimates by assimilating the ESA CCI SM.
Atmospheric corrosion models
Authors: Kreislová K. , Geiplová H. , Barták Z. , Majtás D.
Published: March 2017

A number of damage functions or dose-response equation, which are compared to the atmospheric corrosion of metals with environmental parameters, have been determined in field programs ISOCORRAG, UN ECE ICP Materials Exposure Programme and Multi-Assess. The all of these dose-response equations are derived on field exposure results performed during period 1986-1995 where the SO2 level was relative high at urban and very high at industrial test sites. Several exposure programmes, national and international, of structural metals’ atmospheric corrosion were conducted since the 1970s on Czech atmospheric test sites including on-site measurement of environmental data. All data from these exposure programs were compared with prediction models.
The impact of produced hydrogen gas and calcium zincate on changes of porous structure of cement paste in the vicinity of hot-dip galvanized steel
Authors: Pokorný P. , Pernicová R. , Vokáč M. , Sedlářová I. , Kouřil M.
Published: March 2017

The paper summarizes the impact of produced hydrogen and calcium hydroxyzincate (Ca[Zn(OH)3]2·2H2O) on the formation of the porous structure of cement paste in the vicinity of hot-dip galvanized steel. These substances result from cathodic (hydrogen) and anodic (zincates-formed by reaction with hydroxides) corrosion reactions of hot-dip galvanized steel (or pure zinc) in the cement paste.

The cement binder pore structure was studied by means of mercury porosimetry and analysis of scanning electron microscopy and confocal microscopy images. The porosity of the cement paste at the galvanized steel / cement interphase increased as a result of galvanized steel corrosion while hydrogen was formed. Such a porous structure was maintained throughout the maturation of cement paste. Kinetics of galvanized steel corrosion related primarily to water transport through the binder. The formation of calcium zincate did not result in transition of galvanized steel from active to passive state corrosion.
Some Dynamic Aspects of Photogrammetry Missions Performed by “PW-ZOOM” – The UAV of Warsaw University of Technology
Authors: Rodzewicz Mirosław , Głowacki Dominik , Hajduk Jarosław
Published: March 2017

The article presents the analyses of the flights carried out the by the Unmanned Aerial Vehicle (UAV) named PW-ZOOM used to perform a photogrammetric mission and monitoring of fauna in Antarctic areas. The analyses focus on the deviations of the optical axis of the photo-camera which occurred during photogrammetric flights carried out on the same route but during several Antarctic expeditions performed in subsequent years (2014 and 2015). The results were subjected to correlation tests with weather conditions (wind speed and variability). The basis for these analyses are the data from the onboard signal recorder integrated with an autopilot.
Analysis of Errors of Piezoelectric Sensors used in Weapon Stabilizers
Authors: Korobiichuk Igor
Published: March 2017

Effectiveness of operation of a weapon stabilization system is largely dependent on the choice of a sensor, i.e. an accelerometer. The paper identifies and examines fundamental errors of piezoelectric accelerometers and offers measures for their reduction. Errors of a weapon stabilizer piezoelectric sensor have been calculated. The instrumental measurement error does not exceed 0.1 × 10−5 m/s2. The errors caused by the method of attachment to the base, different noise sources and zero point drift can be mitigated by the design features of piezoelectric sensors used in weapon stabilizers.
Measurements of Concentration differences between Liquid Mixtures using Digital Holographic Interferometry
Authors: Guerrero-Méndez Carlos , Saucedo-Anaya Tonatiuh , Araiza-Esquivel Maria , Balderas-Navarro Raúl E. , López-Martínez Alfonso , Olvera-Olvera Carlos
Published: March 2017

We present an alternative method to detect and measure the concentration changes in liquid solutions. The method uses Digital Holographic Interferometry (DHI) and is based on measuring refractive index variations. The first hologram is recorded when a wavefront from light comes across an ordinary cylindrical glass container filled with a liquid solution. The second hologram is recorded after slight changing the liquid’s concentration. Differences in phase obtained from the correlation of the first hologram with the second one provide information about the refractive index variation, which is directly related to the changes in physical properties related to the concentration. The method can be used − with high sensitivity, accuracy, and speed − either to detect adulterations or to measure a slight change of concentration in the order of 0.001 moles which is equivalent to a difference of 0.003 g of sodium chloride in solutions. The method also enables to measure and calculate the phase difference among each pixel of two samples. This makes it possible to generate a global measurement of the phase difference of the entire sensed region.
Effects of Radiation Doses on the Photostimulated Luminescence Response of Certain Herbs and Spices
Authors: Sandeva Ivana , Spasevska Hristina , Ginovska Margarita , Stojanovska-Georgievska Lihnida
Published: March 2017

Ionizing radiation applied on food eliminates harmful microorganisms, prevents sprouting and delays ripening. All methods for detection of irradiated food are based on physical, chemical, biological or microbiological changes caused by the treatment with ionizing radiation. When minerals are exposed to ionizing radiation, they accumulate radiation energy and store it in the crystal lattice, by which some electrons remain trapped in the lattice. When these minerals are exposed to optical stimulation, trapped electrons are released. The phenomenon, called optically stimulated luminescence or photostimulated luminescence, occurs when released electrons recombine with holes from luminescence centers in the lattice, resulting in emission of light with certain wavelengths.

In this paper, the results of measurements performed on seven different samples of herbs and spices are presented. In order to make a comparison between luminescence signals from samples treated with different doses, unirradiated samples are treated with Co-60 with doses of 1 kGy, 5 kGy and 10 kGy. In all cases it was shown that the higher the applied dose, the higher the luminescence signal.
A New Approach to Measurement of Frequency Shifts Using the Principle of Rational Approximations
Authors: Murrieta-Rico Fabian N. , Petranovskii Vitalii , Sergiyenko Oleg Y. , Hernandez-Balbuena Daniel , Lindner Lars
Published: March 2017

When a frequency domain sensor is under the effect of an input stimulus, there is a frequency shift at its output. One of the most important advantages of such sensors is their converting a physical input parameter into time variations. In consequence, changes of an input stimulus can be quantified very precisely, provided that a proper frequency counter/meter is used. Unfortunately, it is well known in the time-frequency metrology that if a higher accuracy in measurements is needed, a longer time for measuring is required. The principle of rational approximations is a method to measure a signal frequency. One of its main properties is that the time required for measuring decreases when the order of an unknown frequency increases. In particular, this work shows a new measurement technique, which is devoted to measuring the frequency shifts that occur in frequency domain sensors. The presented research result is a modification of the principle of rational approximations. In this work a mathematical analysis is presented, and the theory of this new measurement method is analysed in detail. As a result, a new formalism for frequency measurement is proposed, which improves resolution and reduces the measurement time.
A mathematical/physics carbon emission reduction strategy for building supply chain network based on carbon tax policy
Authors: Li Xueying , Peng Ying , Zhang Jing
Published: March 2017

Under the background of a low carbon economy, this paper examines the impact of carbon tax policy on supply chain network emission reduction. The integer linear programming method is used to establish a supply chain network emission reduction such a model considers the cost of CO2 emissions, and analyses the impact of different carbon price on cost and carbon emissions in supply chains. The results show that the implementation of a carbon tax policy can reduce CO2 emissions in building supply chain, but the increase in carbon price does not produce a reduction effect, and may bring financial burden to the enterprise. This paper presents a reasonable carbon price range and provides decision makers with strategies towards realizing a low carbon building supply chain in an economical manner.
The genus Clunio Haliday, 1855 from Egypt (Hurghada, Red Sea) with a description of the larva of Clunio sp.1 (Diptera, Chironomidae, Orthocladiinae)
Authors: Abdelsalam Khaled Mahmoud
Published: March 2017

Larval populations of Clunio sp.1 are reported for the first time from marine fouling samples obtained in Hurghada during November 2015. This is a new record for the Egyptian Red Sea fauna. A full structural description of the larva is provided and its local distribution is discussed.
Genetic counselling, BRCA1/2 status and clinico-pathologic characteristics of patients with ovarian cancer before 50 years of age
Authors: Cvelbar Mirjam , Hocevar Marko , Novakovic Srdjan , Stegel Vida , Perhavec Andraz , Krajc Mateja
Published: March 2017

Background

In Slovenia like in other countries, till recently, personal history of epithelial ovarian cancer (EOC) has not been included among indications for genetic counselling. Recent studies reported up to 17% rate of germinal BRCA1/2 mutation (gBRCA1/2m) within the age group under 50 years at diagnosis. The original aim of this study was to invite to the genetic counselling still living patients with EOC under 45 years, to offer gBRCA1/2m testing and to perform analysis of gBRCA1/2m rate and of clinico-pathologic characteristics. Later, we added also the data of previously genetically tested patients with EOC aged 45 to 49 years.

Patients and methods

All clinical data have to be interpreted in the light of many changes happened in the field of EOC just in the last few years: new hystology stage classification (FIGO), new hystology types and differentiation grades classification, new therapeutic possibilities (PARP inhibitors available, also in Slovenia) and new guidelines for genetic counselling of EOC patients (National Comprehensive Cancer Network, NCCN), together with next-generation sequencing possibilities.

Results

Compliance rate at the invitation was 43.1%. In the group of 27 invited or previously tested patients with EOC diagnosed before the age of 45 years, five gBRCA1/2 mutations were found. The gBRCA1/2m detection rate within the group was 18.5%. There were 4 gBRCA1 and 1 gBRCA2 mutations detected. In the extended group of 42 tested patients with EOC diagnosed before the age of 50 years, 14 gBRCA1/2 mutations were found. The gBRCA1/2m detection rate within this extended, partially selected group was 33.3%. There were 11 gBRCA1 and 3 gBRCA2 mutations detected.

Conclusions

The rate of gBRCA1/2 mutation in tested unselected EOC patients under the age of 50 years was higher than 10%, namely 18.5%. Considering also a direct therapeuthic benefit of PARP inhibitors for BRCA positive patients, there is a double reason to offer genetic testing to all EOC patients younger than 50 years. Regarding clinical data, it is important to perform their re-interpretation in everyday clinical practice, because this may influence therapeutic possibilities to be offered.
Serological Tests for Acquired Syphilis in Immuno-competent Patients
Authors: Golušin Zoran , Jovanović Marina , Matić Milan , Vujanović Ljuba , Roš Tatjana , Jeremić Biljana
Published: March 2017

Serological tests represent a valuable tool for the diagnosis and monitoring the syphilis treatment. Non-treponemal antibodies are nonspecific to detect the infection, but antibody titers are used to monitor the effects of syphilis treatment. A definitive diagnosis of syphilis is made using treponemal tests, because they detect specific antibodies to the treponemal strains or treponemal fragments, which cause syphilis. These tests may remain reactive for years, sometimes for life, regardless of the therapy outcome. Even after successful treatment, approximately 85% of patients remain positive for treponemal antibodies for the rest of their lives. However, treponemal tests cannot differentiate past infections from a current infection. Therefore, we use a combination of specific and non-specific tests, the two most frequently used diagnostic algorithms. The traditional algorithm begins with a non-treponemal assay, and if it is positive, the treponemal test is done. A positive treponemal test indicates syphilis. The reverse serology algorithm detects early, primary, and treated syphilis that may be missed with traditional screening. However, non-treponemal test is necessary to detect patients with active syphilis.