The paper deals with the probability estimates of temperature extremes (annual temperature maxima and heat waves) in the Czech Republic. Two statistical methods of probability estimations are compared; one based on the stochastic modelling of time series of the daily maximum temperature (TMAX) using the first-order autoregressive (AR(1)) model, the other consisting in fitting the extreme value ...

sugar, which can be extracted from sugar cane and sugar beet, is one of the most important ingredients of food. conducting more research to increase the extraction efficiency of sugar is necessary due to high production of sugar beet and its numerous processing units in northern khorasan province. in this research, the effect of temperature, time and the frequency of ultrasonic waves on mechani...

utilizing polymeric materials for damping mechanical waves is of great importance in various fields of applications such as military camouflage, prevention of structural vibrational energy transfer, and noise attenuation. this ability originates from segmental dynamics of chain-like polymer molecules. damping properties of styrene-butadiene rubbercontaining 10 wt% of monosize polystyrene partic...

The interference of the direct wave from the point source to the receiver and the wave reflected from the impedance ground in a turbulent atmosphere is studied. A parabolic equation approach for calculating the sound pressure p at the receiver is formulated. Then, the parabolic equation is solved by the Rytov method yielding expressions for the complex phases of direct and ground-reflected wave...

Three-dimensional numerical simulations with COBOLD, a new radiation hydrodynamics code, result in a dynamic, thermally bifurcated model of the non-magnetic chromosphere of the quiet Sun. The 3-D model includes the middle and low chromosphere, the photosphere, and the top of the convection zone, where acoustic waves are excited by convective motions. While the waves propagate upwards, they stee...

A new method for the synthesis of nano zero-valent iron (nZVI) was developed in the present study. Ultrasonic waves, as a novel method, were used to synthesize the nanoparticles. The morphology and surface compositions of the particles were characterized by using FESEM, XRD, BET, and particle size analyzer. The synthesized nanoparticles were then utilized as a Fenton-like catalyst to degrade of...

this study simulates the temperature field and temperature stress of concrete face slabs, considering the cold waves that occur during construction as well as the contact friction between the face slabs and the cushion layer. the results show that when a cold wave occurs during construction, the surface and center temperature of the face slabs continually drop with the outside air temperature, ...

During past MANTRA campaigns, ground-based measurements of several long-lived chemical species have revealed quasi-periodic fluctuations on time scales of several days. These fluctuations could confound efforts to detect long-term trends from MANTRA, and need to be understood and accounted for. Using the Canadian Middle Atmosphere Model, we investigate the role of dynamical variability in the l...

Increases in numbers and lengths of heat waves have previously been identified in global temperature records, including locations within Europe. However, studies of changes in UK heat wave characteristics are limited. Historic daily maximum temperatures from 29 weather stations with records exceeding 85 years in length across the country were examined. Heat waves were defined as periods with un...