A reanalysis of the light curve of RT Persei with the W-D code

The UBV photometric observations of RT Per, from Sanwal and Chaubey (1981), were analyzed by the Wilson and Devinney code (1971). The light curves include reflection effects that for the first time has been suggested by Dugan (1911). RT Per has a semi-detached configuration where the lower-mass component is in contact with its respective Roche surface. The higher-mass component very nearly fills its Roche lobe. It has the characteristic of an Algol type system. The absolute dimensions for the primary and secondary of this system were calculated from its spectral types and by combining the photometric solution with inferred component radial velocities (Lu, 1990).     

Forecasting of meteorological drought using Wavelet-ANFIS hybrid model for different time steps (case study: southeastern part of east Azerbaijan province, Iran)

Drought is accounted as one of the most natural hazards. Studying on drought is important for designing and managing of water resources systems. This research is carried out to evaluate the ability of Wavelet-ANN and adaptive neuro-fuzzy inference system (ANFIS) techniques for meteorological drought forecasting in southeastern part of East Azerbaijan province, Iran. The Wavelet-ANN and ANFIS models were first trained using the observed data recorded from 1952 to 1992 and then used to predict meteorological drought over the test period extending from 1992 to 2011. The performances of the different models were evaluated by comparing the corresponding values of root mean squared error coefficient of determination (R ²) and Nash–Sutcliffe model efficiency coefficient. In this study, more than 1,000 model structures including artificial neural network (ANN), adaptive neural-fuzzy inference system (ANFIS) and Wavelet-ANN models were tested in order to assess their ability to forecast the meteorological drought for one, two, and three time steps (6 months) ahead. It was demonstrated that wavelet transform can improve meteorological drought modeling. It was also shown that ANFIS models provided more accurate predictions than ANN models. This study confirmed that the optimum number of neurons in the hidden layer could not be always determined using specific formulas; hence, it should be determined using a trial-and-error method. Also, decomposition level in wavelet transform should be delineated according to the periodicity and seasonality of data series. The order of models with regard to their accuracy is as following: Wavelet-ANFIS, Wavelet-ANN, ANFIS, and ANN, respectively. To the best of our knowledge, no research has been published that explores coupling wavelet analysis with ANFIS for meteorological drought and no research has tested the efficiency of these models to forecast the meteorological drought in different time scales as of yet.     

The photometric observations of ER vulpeculae: photometric analysis with the W-D code

The photometric observations of ER Vul were obtained in UBV light in 1994, at Birouni Observatory, University of Shiraz, Iran. The three light curves, which are almost complete, have been analyzed separately by means of Wilson and Devinney method (1971). The light curves include proximity effects, wave-like distortions, mutual eclipses, and short term light fluctuations. The appropriate value of the mass ratio of this system was found after extensive searches. ER Vul has a detached configuration where the two components are very nearly fill their Roche lobe. ER Vul has the characteristic of a RS CVn type system. The absolute dimensions for the primary and secondary of this system were calculated from its spectral types and by combining the photometric solution with inferred component radial velocities (Northcott and Bakos, 1967).     

Mapping and monitoring of dust storms in Iran by fuzzy clustering and remote sensing techniques

In this research, the frequency of dust storms was prepared at 87 synoptic stations for the period of 1987–2013. These data were classified by means of Fuzzy c-means clustering algorithm. Satellite images of MODIS and brightness temperature index were also used for detection and tracking dust storm of 30 Jun 4 July 2008. The results indicated that Iran is classified in five clusters by the dust-storm-frequencies from which, cluster 5 is reclassified in three clusters because of its wide range. The maximum number of days with dust storms was observed in cluster 1 that includes only Zabol station with the frequency of 790 days with the duration 1987–2013. The minimum number of days with dust storms was observed in cluster 5-3 that includes the stations located in portions of North, Northwest, Northeast Iran and the higher elevations of the Zagros in western Iran. A case study about a severe dust storm in Iran using satellite images indicate that brightness temperature index (BTI) is a desired index for detection and monitoring of dust storms. The source of the investigated dust storms is Iraq and South of the Arabian Peninsula that had influenced the western half of Iran in several days. The frequency of dust storms increased markedly in the west, southwest of Iran and Persian Gulf around as main receptors from emerging dusty areas but it increased slightly in the eastern half of Iran.     

Spatiotemporal shoreline change in Boushehr Province coasts,Iran

Journal of Oceanology and Limnology - Since coastal areas have highly dynamic nature and are one of the most beneficial regions of civilizations, it is of great significance to understand their...     

Degradation of urea by entrapped cross-linked urease aggregates: a combinatorial approach to urease stabilization for environmental and industrial applications

Urease which catalyzes biodegradation of urea to ammonia and carbon dioxide has attracted a great deal of attention as a catalyst in food industry, agriculture and artificial kidneys. Immobilization is a unique approach for enhancement of enzyme stability before enzyme industrialization. In the present work, crude sword bean urease was immobilized in the form of cross-linked enzyme aggregate prior to entrapment in polyacrylamide gel or chitosan beads. No significant change was observed in the kinetic constant value (k _m ) of urease upon formation of cross-linked enzyme aggregate. Entrapment of urease cross-linked aggregates in chitosan beads resulted in complete loss of activity while polyacrylamide-embedded cross-linked urease aggregates were enzymatically active. The optimum temperature for urease was 60 °C (soluble and cross-linked aggregate form) and 70 °C (polyacrylamide-embedded cross-linked aggregate). The optimal pH for urease was 7.0 (soluble and cross-linked aggregate form) and 5.0 (polyacrylamide-embedded cross-linked aggregate). In the other words, immobilization in the form of cross-linked aggregate and entrapment in polyacrylamide matrix could be resulted in the stabilization of urease over a wider pH range. Urease cross-linked aggregate showed improved stability at 60 °C, and its half-life increased about two times. Operational stability of cross-linked urease aggregate was also noticeably improved upon entrapment in polyacrylamide gel. In conclusion, entrapment of carrier-free cross-linked urease aggregate in a polyacrylamide matrix could result in a great improvement in both the storage and operational stabilities of urease.