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In this article, we present some fixed point and coupled fixed point theorems adapted from the notion of F-contraction mappings in Banach spaces (B.S.) via the measure of noncompactness (M.N.C). Then we define and present a new class of generalized F-contractions, to upgrade some results of Falest and Latrach (Bull Bell Math Soc Simon Stevin 22:797–812, 2015). Furthermore, we investigate the solvability of a new system of Volterra integral equations in a Banach Algebra. Finally, the usefulness of the theoretical results is shown by an example.

The present study focuses on the effect of vortex formation on plane velocities in a reservoir. Velocity measurements are performed in the hydraulic model of Karun III dam and hydropower plant. Different vortices were produced at the horizontal intake by changing the submerged depth. Tangential velocities were measured on a rectangular mesh in the reservoir. The results were then processed to plot the contour lines of the plane velocities and study the effect of vortex formation on the flow condition in the reservoir. Contour lines in different submerged depths show that circulation zones are formed in different potential locations over the intakes causing vortex formation. These results were correlated with the location of the appearing vortices observed in the experiments. Experimental data of this study could be useful for numerical modelling of vortex in the reservoirs.

Bottom outlet tunnels are among the most important structures of dam design processes and operation which are encountered with many dangerous problems. This study investigating the flow aeration between emergency and service gates along the bottom tunnel using a large enough physical model of Karun IV Dam bottom outlet. To do so, performance of 12 alternatives was tested to select the best design. Flow characteristics of each alternative have been studied and critical design criteria in view of occurring cavitation hazard has been evaluated. Cavitation indices were calculated along the tunnel from the entrance of the intake to the outlet structure. To eliminate the probability of cavitation hazard, aerators have been designed. Results showed that cavitation hazard was not considerable along the tunnel and installation of aerators between service and emergency gates could definitely diminish the probability of cavitation. Measurements demonstrated that in 60 % opening of service gate the amount of air was maximum by value of 0.024 cm.

A powder mixture of Al/TiO2/H3BO3 = 10/3/6 in molar ratio was used in this study to form the Al2O3–TiB2 ceramic composite via thermite reactions (combustion synthesis). As no combustion synthesis occurred for an unmilled sample in a furnace, the mixture was milled in a planetary ball-mill for various milling times, and the as-milled samples were in situ synthesized in the furnace at a heating rate of 10 °C/min. The differential scanning calorimetry (DSC) measurements were performed with the same heating rate on the unmilled and the as-milled samples to evaluate the influences of the milling on the mechanisms and efficiencies of reactions. Although no combustion synthesis occurred for the unmilled sample in the furnace, two exothermic peaks were detected in its DSC curve after the melting of the Al. For the as-milled samples, significant changes revealed in the DSC curves, suggest that the milling process before the combustion synthesis changed the mechanisms and efficiencies of reactions. In addition, the intensity and the temperature of the exothermic peaks in the DSC curves changed by increasing the milling time. According to the XRD analyses, by enhancing the milling time, the purity of the final products would increase, confirming that the efficiency of the reactions increased. Finally, the microstructures of the as-milled and as-synthesized samples were examined by a SEM, and it was shown that the morphology of the reactant powders was altered by increasing the milling time.

In the coming decades, global warming and increase in temperature, in different regions of the world, may change indoor and outdoor thermal comfort conditions and human health. The aim of this research was to study the effects of global warming on thermal comfort conditions in indoor ambiences in Iran. To study the increase in temperature, model for assessment of greenhouse-gas induced climate change scenario generator compound model has been used together with four scenarios and to estimate thermal comfort conditions, adaptive model of the American Society of Heating, Refrigerating and Air-conditioning Engineers has been used. In this study, Iran was divided into 30 zones, outdoor conditions were obtained using meteorological data of 80 climatological stations and changes in neutral comfort conditions in 2025, 2050, 2075 and 2100 were predicted. In accordance with each scenario, findings from this study showed that temperature in the 30 zones will increase by 2100 to between 3.4 °C and 5.6 °C. In the coming decades and in the 30 studied zones, neutral comfort temperature will increase and be higher and more intense in the central and desert zones of Iran. The low increase in this temperature will be connected to the coastal areas of the Caspian and Oman Sea in southeast Iran. This increase in temperature will be followed by a change in thermal comfort and indoor energy consumption from 8.6 % to 13.1 % in air conditioning systems. As a result, passive methods as thermal inertia are proposed as a possible solution.

One of the climatic phenomena that affects low temperatures in Iran is the penetration of tongues of high pressures from Siberia during the cold period of the year. Therefore, in order to investigate the effect of Siberia’s high pressure on the occurrence of low temperatures in Iran, air pressure at sea level for the region from 45 to 125°E and 25 to 65°N within the time range of one day and the location range of 2.5°, 561 grids for the month of December from the years 1948 to 2010 was extracted from the NOAA website and evaluated. It is necessary to explain that all pressure data for the studied range were classified into clusters using statistical analysis. Seven of these clusters were chosen as dominant. Of these, three prominent, important patterns, including clusters 3, 4, and 6, together account for 62.26 % our records in during December. In these three patterns, the effect of Siberia’s high pressure on the occurrence of low temperatures in Iran during December is more visible compared to the other patterns. On the other hand, simultaneous with the occurrence of the fourth cluster, with 99 % of Iran’s entire area, the maximum area of the country experiences below-average temperatures, and simultaneous with the occurrence of the second cluster, only 3 % of the entire area of Iran experiences below-average temperatures during December. In addition, we discovered a significant trend of increasing temperatures for most of the clusters in Iran, which can be attributed to global warming.

The phase and elemental composition, substructure, orientation, and relief of Pd-Cu thin films produced by magnetron sputtering have been investigated using the techniques of TEM, HEED, and AFM. Three-orientation epitaxial β-phase structures (CsCl-type lattice) have been obtained by plasma-ion sputtering a Pd-Cu target on (001) fluorphlogopite (F) cleavages in the substrate temperature range of 550–800 K. The β-phase crystallites in the two-phase epitaxial solid solution films were oriented, with respect to the α-phase, according to Nishiyama—Wassermann and Kurdyumov—Sachs relations. Single-crystal films of α-and β-phase solid solutions have been grown on fluorphlogopite. The effect of the second component appeared as the formation of (001)[110] βCuAu ∥ (001)[100]F-type orientations.

1. The catalytic activity with respect to the dehydrogenation of cyclohexane on metallurgical alloys of Pd, containing from 7 to 20% Rh, decreases with the removal of H2 from the alloy and is entirely restored after treatment of the alloys with H2. The catalytic activity of the alloys increases when the temperature of their treatment with air is increased from 350 to 750‡. 2. An increase in the catalytic activity of Pd-Rh alloys was detected after experiments conducted at 450–470‡ in a stream of argon, evidently associated with the removal of firmly adsorbed hydrogen.

1. The catalytic activity of binary alloys of palladium containing 4.4–9.2% Ru was investigated as a function of' the conditions of their heat treatment in an atmosphere of various gases (air, H2, Ar). 2. The results of the investigation were treated according to a program permitting calculation of the parameters of the Arrhenius equation on the assumption of normal and logarithmic-normal distributions of their values. The correctness of the hypothesis of a logarithmic-normal distribution was demonstrated. 3. Raising the temperature of treatment of the alloys in a stream of air from 350 to 750°, as well as repeated treatment in a stream of air at 750°, caused an appreciable increase in the catalytic activity, associated with an increase in the preexponential factors. An even greater increase in the activity, due to a decrease in the activation energy, is also achieved as a result of treatment of the catalyst with air, and then with H2, at 750° with rapid cooling in H2.

Palladium-copper alloys, which contain from 37 to 42% Cu, have both a high hydrogen permeability and a substantial catalytic activity in the de hydrogenation of 1,2-cyclohexanediol, which makes it possible to use them as membrane catalysts for this reaction.

1. Palladium alloyed with 6% Ru is characterized by relatively high recrystallization temperature: Tre=0.57Tm. 2. Annealing at 900–1100° leads to formation of a homogeneous fine-grained structure with substantial reduction of the hardness.