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1.
Measurement of the branching fraction and ▫$CP$▫ asymmetry for ▫$B \to \bar{D}^0 \pi$▫ decays
T. Bloomfield, Jyoti Prakash Biswal, Marko Bračko, Samo Korpar, Peter Križan, Rok Pestotnik, Tomaž Podobnik, Marko Starič, Luka Šantelj, 2022, izvirni znanstveni članek

Opis: We measure the branching fractions and CP asymmetries for the decays B⁰ → D¯ 0π⁰ and B⁺ → D¯ 0π⁺, using a data sample of 772 × 10⁶ BB¯ pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB e⁺e− collider. The branching fractions obtained and direct CP asym-metries are B(B⁰ → D¯ 0π⁰)=[2.70 0.06(stat) 0.10(syst)]×10−⁴, B(B⁺ → D¯ 0π⁺)=[4.53 0.02(stat) 0.15(syst)]×10−³, ACP(B⁰ → D¯ 0π⁰)= [+0.42 2.05(stat) 1.22(syst)]%, and ACP(B⁺ → D¯ 0π⁺) = [+0.19 0.36(stat) 0.57(syst)]%. The measurements of B are the most precise to date and are in good agreement with previous results, as is the measurement of ACP(B⁺ → D¯ 0π⁺). The measurement of ACP for B⁰ → D¯ 0π⁰ is the first for this mode, and the value is consistent with Standard Model expectations.
Ključne besede: branching fraction, hadronic decays, particle decays, mesons, CP violation, precision measurements
Objavljeno v DKUM: 17.08.2023; Ogledov: 223; Prenosov: 21
.pdf Celotno besedilo (506,19 KB)
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2.
Processing of signals produced by strain gauges in testing measurements of the bridges
Boštjan Kovačič, Rok Kamnik, Andrej Štrukelj, Nikolai Ivanovich Vatin, 2015, objavljeni znanstveni prispevek na konferenci

Opis: Practical example of signal processing from strain gauge, inductive transducer and total station measurements are used to illustrate the features of the bridge load testing measurements. FFT provides accurate representation of physical behavior for static and dynamic signals obtained when loading the bridge. As a reference measurement the signal from inductive transducer was taken. A static part of the load test was also geodetically measured and theoretically calculated. The results are comparable.
Ključne besede: bridges, measurements, strain gauge, load test, deformation, strain, signal processing
Objavljeno v DKUM: 12.07.2023; Ogledov: 331; Prenosov: 17
.pdf Celotno besedilo (500,43 KB)
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GNSS monitoring of geologically demanding areas
Boštjan Kovačič, Boško Pribičević, Rok Kamnik, 2016, izvirni znanstveni članek

Opis: Displacement research using the three-dimensional global navigation satellite system (GNSS) as part of geodetic monitoring is becoming the key investigation for establishing a cause-and-effect relationships model between external natural factors, on the one hand, and the criteria that describes the level of functionality and safety of the observed natural or artificial object, on the other, in cases of motion of an object in space and time. The main objective of the deformation analysis is to confirm the stabilities of the reference points of a geodetic network, which are used to determine the movements of the control points that are stabilized on the observed objects. The assumption about the stabilities of certain reference points must be based on reasonable grounds, underpinned by measurements and proven by numerical methods. This is one part of the results of the deformation analysis when determining the extent of the movements and deformations. To do this a transformation is used in which a comparison is made between the coordinates of the points for two separate epochs. On the basis of the estimated transformation parameters, possible movements can be concluded within the reference points, i.e., on whether the datum parameters have changed. After confirming the stability of the geodetic network the coordinate differences of identical points measured within the different time windows can be determined as displacements and/or deformations of an object. In this paper one viaduct was assessed through geology and tectonic activities and also a load test of the viaduct was performed. The viaduct is in a quite active region, but the load test showed that the bridge response to the load is as expected.
Ključne besede: geodesy, geotehnics, monitoring, GNSS measurements, geology, deformation analysis, geodetic network
Objavljeno v DKUM: 18.06.2018; Ogledov: 1468; Prenosov: 65
.pdf Celotno besedilo (630,78 KB)
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5.
Measurement and interpretation of the small strain stifness of Boštanj silty sand
Gregor Vilhar, Vojkan Jovičić, 2009, izvirni znanstveni članek

Opis: This paper presents measurements, and an interpretation of these measurements, based on the use of bender-element probes for Boštanj silty sand. The samples were prepared at different initial void ratios and isotropically compressed up to 5 MPa. The bender-element technique was used to determine the dynamic shear modulus ($G_0$) of the soils at very small strains. The multiple bender-element probes were shot at different excitation frequencies in order to increase the reliability of the measurements. The $G_0$ stiffness was determined by using three different techniques: a) the first-time arrival, b) the phase-change method and c) the cross-correlation method. The systematic differences observed between the $G_0$ values, calculated using the three techniques, are discussed. The variation of $G_0$ in the log$G_0$ - log$p'$ plane was evaluated for the Boštanj silty sand and compared with other sands.
Ključne besede: silty sand, triaxial testing, small strain stiffness, bender elements, time-domain and frequency-domain, measurements
Objavljeno v DKUM: 06.06.2018; Ogledov: 1063; Prenosov: 127
.pdf Celotno besedilo (706,26 KB)
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6.
Displacements in the exploratory tunnel ahead of the excavation face of Šentvid tunnel
Jure Klopčič, Janko Logar, Tomaž Ambrožič, Andrej Štimulak, Aleš Marjetič, Sonja Bogatin, Bojan Majes, 2006, izvirni znanstveni članek

Opis: Fitting the displacement function to the measured displacements enables the assessment of the stabilization process of the observed cross section and the determination of its normal behaviour. The displacement function consists of three parts. Whilst the third part has been successfully applied for several times and thus proven to be very well defined, the first two parts were defined only on the basis of numerical simulations. To overcome this deficiency and to obtain the necessary coefficients of the pre-face part of the displacement function, the 3D displacement measurements ahead of the face due to tunneling should be performed. Such measurements were performed in the exploratory tunnel of the Šentvid tunnel during the excavation of the main tunnel. This paper presents the Šentvid tunnel project, the method of the 3D displacement measurements, the results of these measurements and their interpretation according to the geological structure of the site with an emphasis on items important for the coefficients of the displacement function.
Ključne besede: tunnels, exploratory tunnel, geodetic displacement measurements, pre-face displacements
Objavljeno v DKUM: 17.05.2018; Ogledov: 1339; Prenosov: 93
.pdf Celotno besedilo (660,40 KB)
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7.
The assesment of pile shaft resistance based on axial strain measurements during the loading test
Andrej Štrukelj, Stanislav Škrabl, Ksenija Štern, Janko Logar, 2005, izvirni znanstveni članek

Opis: Near Maribor, a new bridge over the Drava river is being under construction. Before the main works actually started, static and dynamic loading tests of piles were performed. The goal of the static loading test was to determine the bearing capacitiy of the test pile. It was also interesting to determine the share of the axial load distributed on the shaft and pile toe. In order to measure the distribution of the axial force along the pile, a specially made steel canal was built in the pile before concreting. Inside this canal the strain gauges were distributed evenly at the distance of one meter. The strains were measured for each loading phase in all measuring points. The distribution of the axial force was assessed from the obtained results and based on the distribution of the axial force the shaft resistance could be determined. The unexpectedly high bearing capacity of the pile shaft made the obtained results highly interesting. In this paper, measuring methods and measuring results are discussed. Behaviour of the pile and the soil during the loading test were also modelled by axial symmetric and three dimensional models. The calculated and measured results show a very good agreement.
Ključne besede: civil engineering, bridges, soil mechanics, pile shaft resistance, loading test, strain measurements, elastoplastic soil modelling, finite element method
Objavljeno v DKUM: 16.05.2018; Ogledov: 1277; Prenosov: 73
.pdf Celotno besedilo (987,58 KB)
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8.
Synthesis, crystal structure and magnetic properties of a new hydroxylammonium fluoroferrate
Brina Dojer, Matjaž Kristl, Zvonko Jagličić, Amalija Golobič, Marta Kasunič, Mihael Drofenik, 2012, izvirni znanstveni članek

Opis: This paper reports on the synthesis of a new hydroxylammonium fluoroferrate, with the formula $(NH_3OH)_3FeF_6$, obtained after dissolving iron powder in hydrofluoric acid and adding solid $NH_3OHF$. This new compound has been characterized by chemical and thermal analysis, single-crystal X-ray diffraction, and magnetic measurements. The title compound crystallizes trigonal, R3c, with cell parameters a = 11.4154(2) Å, c = 11.5720(2) Å, Z = 6. The structure consists of $NH_3OH^+$ cations and isolated $FeF_6^{3–}$ octahedra in which the central ion lies on a threefold axis. The oxygen and nitrogen atoms of the hydroxylammonium cations are donors of hydrogen bonds to fluoride anions, resulting in a network of hydrogen bonds between counterions. The effective magnetic moment $µ_{eff}$ = 5.8 BM was calculated and perfectly matches the expected value of high-spin Fe(III) ions. The thermal decomposition of the compound was studied by TG, DSC, and X-ray powder diffraction.
Ključne besede: inorganic chemistry, crystallography, coordination compounds, synthesis, crystal structure, characterization of compounds, determination of the structure of compounds, X-ray diffraction, magnetic measurements, thermal analysis, TG, DSC, hydrogen bond, metal complexes, hydroxylammonium fluoromethalatehydroxylammonium, fluoroferrate
Objavljeno v DKUM: 25.08.2017; Ogledov: 1849; Prenosov: 67
.pdf Celotno besedilo (198,42 KB)
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9.
A silver/silver sulphide selective electrode prepared by means of chemical treatments of silver wire
Danilo Dobčnik, Igor Gros, Mitja Kolar, 1998, izvirni znanstveni članek

Opis: The preparation and usability of a sulphide ion selective electrode, prepared by means of chemical pretreatment of silver wire with an ammonium perdisulphate solution, and the sulphidization in an alkaline sulphide solution are described. The electrode is suitable for direct potentiometric measuring of sulphide in alkaline solutions of concentrations down to ▫$1 X 10^{-6} mol/L$▫. The 45 min required for each chemical treatment are enough for the preparation of the described electrode.
Ključne besede: analytical chemistry, ion selective electrode, preparation, silver wire, potentiometric measurements, sulphide ions
Objavljeno v DKUM: 17.08.2017; Ogledov: 1181; Prenosov: 119
.pdf Celotno besedilo (80,69 KB)
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10.
Force measurements on teeth using fixed orthodontic systems
Rebeka Rudolf, Janko Ferčec, 2013, pregledni znanstveni članek

Opis: The fixed orthodontic appliance consists of brackets that are bonded to the teeth. When the wire is engaged in the slot of the brackets, it generates forces for orthodontic tooth movement. The change in periodontal blood supply provides a biological response which leads to remodelling of the alveolar bone and the orthodontic tooth movement. Many variables influencing orthodontic treatment cannot be controlled fully, such as growth and tissue response to appliances. However, the force placed on the tooth should be a controllable variable, and a careful study of the physics underlying clinical applications can help in reducing undesirable side effects. The properties of orthodontic wires such as: strength, stiffness, elasticity and spring-back define their clinical usefulness. The ideal orthodontic wire should exhibit the following properties: large spring-back, low stiffness, good formability, high stored energy, biocompatibility and environmental stability, low surface friction, and the capability of being welded or soldered to auxiliaries. The ideal arch wire has not been introduced yet. Once the wire is activated or bent, it is the unloading or deactivating forces that produce the orthodontic tooth movement. For these reasons, it is necessary to know the force level caused by each individual wire used in orthodontic treatment. Finally, the purpose of this paper is a presentation of force measurements which are generated by different super-elasticity NiTi wires.
Ključne besede: force measurements, orhodontic system, teeth, NiTi alloys
Objavljeno v DKUM: 09.08.2017; Ogledov: 1145; Prenosov: 340
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