Dry and wet spells at Itabaina (NE Brazil)

Results of a study of dry and wet spells at Itabaina, a semi-arid station in northeast Brazil, are presented in this paper. Frequency distributions of dry spells of different durations at the station are compared with those derived from three statistical models. It is found that the Eggenberger-Polya and the geometric model provide better results than the logarithmic model. Frequency distribution of wet spells during the three rainiest months of the year shows that rainfall persistency reaches a maximum value on the fifth day of a rainy spell

A Novel Multi-Band Patch Antenna on Metamaterial Substrate for Ku band applications

In this paper, a metamaterial based compact multiband microstrip antenna is proposed which can give high gain and directivity. Metamaterial are periodic structures and have been intensively investigated due to the particular features such as ultra-refraction phenomenon and negative permittivity and/or permeability. A metamaterial based microstrip patch antenna with enhanced characteristics and multi band operation will be investigated in this work. The multiple frequency operation will be achieved by varying the capacitance of the metamaterial structure with the help of metallic loadings placed in each metamaterial unit cells. The potential impacts will be miniaturization, reduced cost and reduced power consumption since multiple antennas operating at different frequencies are replaced by a single antenna which can operate at multiple frequencies. The proposed microstrip patch antenna will have its frequencies of operation in the Ku band. The proposed structure is simulated using HFSS

Characteristics of VHF radiowave scintillations over a solar cycle (1983?1993) at a low-latitude station: Waltair (17.7°N, 83.3°E)

International audienceThe characteristics of VHF radiowave scintillations at 244 MHz (FLEETSAT) during a complete solar cycle (1983?93) at a low-latitude station, Waltair (17.7°N, 83.3°E), are presented. The occurrence of night-time scintillations shows equinoctial maxima and summer minima in all the epochs of solar activity, and follows the solar activity. The daytime scintillation occurrence is negatively correlated with the solar activity and shows maximum occurrence during the summer months in a period of low solar activity. The occurrence of night-time scintillations is inhibited during disturbed days of high solar activity and enhanced during low solar activity

Estimation of incoming global solar radiation and its diffuse component at the surface in Paraiba state (NE Brazil)

Results of a study on the estimation of mean monthly values of incoming global solar radiation and its diffuse component at some stations in Paraiba state (NE Brazil) are presented in this paper. Radiation data at four stations is used. ˚Angstr¨om-type equations are derived for the estimation of global radiation and the diffuse fraction of global radiation is expressed in terms of the clearness index and the sunshine ratio. The applicability of previously reported equations for stations in this region is investigated

A case series of sarcomatoid transitional cell carcinoma of renal pelvis and collecting duct carcinoma of kidney

Sarcomatoid transitional cell carcinoma (TCC) of the renal pelvis and collecting duct carcinoma (CDC) of the kidney are rare types of malignant renal tumors with aggressive behavior. Here, we report a case series of these tumors, in males of age 65 years and 72 years, respectively. In both the cases, the left kidney was affected and they underwent the left-sided radical nephroureterectomy. Histologically, sarcomatoid TCC showed two components with invasive TCC and areas with spindle cells and osteoclastic type of giant cells. The immunohistochemistry showed diffuse positivity for CK7 and negativity for CK20 and p63 in both the components. CDC showed tubule-papillary patterns with marked desmoplasia. The patients were disease free after a follow-up of 12 months and 2½ years, respectively, without any adjuvant therapy

Hydrodynamic Processes and Inlet Dynamics of Chilka, A Tropical Lagoon on East Coast of India

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Assessment of ground water quality in an industrial agglomeration of Visakhapatnam, A. P

ABSTRACT Ground water is increasingly used for domestic, agricultural, industrial and other activities. Quality of water is the most important factor for any use; be it domestic or any other purposes. Indiscriminate use of ground water deteriorates the quality and quantity of water. The present work reports the physico-chemical characteristics of the ground waters collected from an industrialized urban agglomeration of Visakhapatnam city, Andhra Pradesh. The physicochemical parameters include pH, Turbidity, Conductivity, Total Dissolved Solids, Chlorides, Sulphates, Total Hardness, Calcium, Magnesium, Total Alkalinity, Nitrates and Fluorides. Though the data show that majority of the values are compatible with the maximum allowable standards recommended by BIS, still in depth studies are to be carried out to decide its suitability for safe drinking and domestic use. It is possible that the concentration of the dissolved impurities may increase further if the recommended norms for discharging industrial effluents are not adhered