EFFECT OF FIBRE ASPECT RATIO AND FIBRE VOLUME FRACTION ON THE EFFECTIVE FRACTURE ENERGY OF ULTRA-HIGH-PERFORMANCE FIBRE-REINFORCED CONCRETE

This paper investigates the effective fracture energy of UHPFRC with various fibre volume fractions and various fibre aspect ratios. We have concluded that the effective fracture energy is dependent on both the fibre volume fraction and the fibre aspect ratio. In addition, we have found that both dependencies follow a linear trend

A Comparison of Selected Modifications of the Particle Swarm Optimization Algorithm

We compare 27 modifications of the original particle swarm optimization (PSO) algorithm. The analysis evaluated nine basic PSO types, which differ according to the swarm evolution as controlled by various inertia weights and constriction factor. Each of the basic PSO modifications was analyzed using three different distributed strategies. In the first strategy, the entire swarm population is considered as one unit (OC-PSO), the second strategy periodically partitions the population into equally large complexes according to the particle’s functional value (SCE-PSO), and the final strategy periodically splits the swarm population into complexes using random permutation (SCERand-PSO). All variants are tested using 11 benchmark functions that were prepared for the special session on real-parameter optimization of CEC 2005. It was found that the best modification of the PSO algorithm is a variant with adaptive inertia weight. The best distribution strategy is SCE-PSO, which gives better results than do OC-PSO and SCERand-PSO for seven functions. The sphere function showed no significant difference between SCE-PSO and SCERand-PSO. It follows that a shuffling mechanism improves the optimization process

EFFECTIVE FRACTURE ENERGY OF ULTRA-HIGH-PERFORMANCE FIBRE-REINFORCED CONCRETE UNDER INCREASED STRAIN RATES

The main objective of this paper is to contribute to the development of ultra-high performance fibre reinforced concrete (UHPFRC) with respect to its effective fracture energy. Effective fracture energy was investigated in this paper considering different fibre volume fractions and different strain rates. It was concluded that the effective fracture energy is dependent on the strain rate. In addition, it was found that higher fibre volume fractions tend to decrease the sensitivity of the UHPFRC to increased strain rates

The Effect of a Spiral Gradient Magnetic Field on the Ionic Conductivity of Water

We discuss the experimental verification of changes in the structure of a liquid water sample inserted in a special spiral “gradient” magnetic field. The magnetic flux components are characterized by a high degree of inhomogeneity; thus, a gradient is found in the monitored section of space. The relevant measurement of the modified, rearranged water sample pointed to a specific ion conductivity lower than that of the untreated water. The results of the experiment, where a sample of demineralized water was exposed to a spiral “gradient“ magnetic field for the period of 5 min, show decreased ion conductivity in the examined samples

COMPARISON OF METHODS USED FOR SEISMIC ANALYSIS OF STRUCTURES

This paper investigates effects of the seismic load to a structure. The article describes main methods of the definition and practical application of the seismic load based on the Standard Eurocode 8. There was made a comparison of all methods using the same structure. A simple two-storeyed concrete 2D-frame with fixed joints was chosen. A one another model with rigid beams for some calculations was defined. The second model can be used for hand-calculations as a cantilever with two masses. The paper describes main dynamic properties of the chosen structure. Seismic load was defined by lateral force method, modal response spectrum, non-linear time-history analysis and pushover analysis. The time-history analysis is represented by accelerograms. There were made linear and non-linear calculations

Parameter Estimation in Rainfall-Runoff Modelling Using Distributed Versions of Particle Swarm Optimization Algorithm

The presented paper provides the analysis of selected versions of the particle swarm optimization (PSO) algorithm. The tested versions of the PSO were combined with the shuffling mechanism, which splits the model population into complexes and performs distributed PSO optimization. One of them is a new proposed PSO modification, APartW, which enhances the global exploration and local exploitation in the parametric space during the optimization process through the new updating mechanism applied on the PSO inertia weight. The performances of four selected PSO methods were tested on 11 benchmark optimization problems, which were prepared for the special session on single-objective real-parameter optimization CEC 2005. The results confirm that the tested new APartW PSO variant is comparable with other existing distributed PSO versions, AdaptW and LinTimeVarW. The distributed PSO versions were developed for finding the solution of inverse problems related to the estimation of parameters of hydrological model Bilan. The results of the case study, made on the selected set of 30 catchments obtained from MOPEX database, show that tested distributed PSO versions provide suitable estimates of Bilan model parameters and thus can be used for solving related inverse problems during the calibration process of studied water balance hydrological model

Plán pro univerzální slabičnou segmentaci

summary:Prostorově a časově efektivní segmentace (dělení slov) přirozených jazyků zůstává jádrem každého sázecího systému, ať už jde o TeX, webový prohlížeč nebo mobilní operační systém. Ve většině jazyků je dnes pragmaticky preferováno slabičné dělení reflektující výslovnost při čtení. Vzhledem k tomu, že přepínání jazyků často není v textech označeno, renderovací stroj (webový prohlížeč či TeX) potřebuje univerzální slabikovou segmentaci. V předloženém článku ukazujeme proveditelnost této myšlenky tím, že nabízíme prototypové řešení dvou hlavních problémů: A) použití Patgenu ke generování vzorů pro několik jazyků najednou; a B) neexistence podpory Unicode v nástrojích jako Patgen nebo TeX (vzory v kódování UTF-16). Pro A) jsme ke generování univerzálních slabičných vzorů použili seznamy slov devíti slabičných jazyků (čeština, slovenština, gruzínština, řečtina, polština, ruština, turečtina, turkmenština a ukrajinština). Pro B) jsme vytvořili verzi Patgen, která používá datovou strukturu Judy array, a porovnali její efektivitu s implementací trie. S údaji z těchto devíti jazyků ukazujeme, že: A) vyvinutí univerzálních, obecných slabičných vzorů s vysokým pokrytím je možné, a to s velkým dopadem na prakticky všechny sázecí stroje včetně webových prohlížečů; a B) podpora Unicode znaků ve vzorech dělení slov v programech TeX a Patgen je možná pomocí Judy array.summary:Space- and time-effective segmentation (word hyphenation) of natural languages remains at the core of every document rendering system, be it TeX, web browser, or mobile operating system. In most languages, segmentation mimicking syllabic pronunciation is a pragmatic preference today. As language switching is often not marked in rendered texts, the typesetting engine needs universal syllabic segmentation. In this article, we show the feasibility of this idea by offering a prototype solution to two main problems: A) Using Patgen to generate patterns for several languages at once; and B) lack of Unicode support in tools like Patgen or TeX (patterns in UTF-16 encoding) is missing. For A), we have applied it to generating universal syllabic patterns from wordlists of nine syllabic, as opposed to etymology-based, languages (namely, Czech, Slovak, Georgian, Greek, Polish, Russian, Turkish, Turkmen, and Ukrainian). For B), we have created a version of Patgen that uses the Judy array data structure and compared its effectiveness with the trie implementation. With the data from these nine languages, we show that: A) developing universal, up-to-date, high-coverage, and highly generalized universal syllabic segmentation patterns is possible, with a high impact on virtually all typesetting engines, including web page renderers; and B) bringing wide character support into the hyphenation part of the TeX suite of programs is possible by using Judy arrays

Fracture surface of normal strength concrete under various loading rates

This work was supported by the Ministry of Interior of the Czech Republic [grant number VI20172020061]. The authors also acknowledge assistance from the technical staff at the Experimental Centre, Faculty of Civil Engineering, CTU in Prague

Projected changes of rainfall event characteristics for the Czech Republic

Projected changes of warm season (May–September) rainfall events in an ensemble of 30 regional climate model (RCM) simulations are assessed for the Czech Republic. Individual rainfall events are identified using the concept of minimum inter-event time and only heavy events are considered. The changes of rainfall event characteristics are evaluated between the control (1981–2000) and two scenario (2020–2049 and 2070–2099) periods. Despite a consistent decrease in the number of heavy rainfall events, there is a large uncertainty in projected changes in seasonal precipitation total due to heavy events. Most considered characteristics (rainfall event depth, mean rainfall rate, maximum 60-min rainfall intensity and indicators of rainfall event erosivity) are projected to increase and larger increases appear for more extreme values. Only rainfall event duration slightly decreases in the more distant scenario period according to the RCM simulations. As a consequence, the number of less extreme heavy rainfall events as well as the number of long events decreases in majority of the RCM simulations. Changes in most event characteristics (and especially in characteristics related to the rainfall intensity) depend on changes in radiative forcing and temperature for the future periods. Only changes in the number of events and seasonal total due to heavy events depend significantly on altitude