The supply of the public lacus of Pompeii, estimated from the discharge of their overflow channels

The term lacus generally identified the public fountains in the main streets of ancient Roman towns, providing for the population daily water demand. The simplest lacus consisted of a stone basin and a spout stone, concealing one or two supply pipes. 35 street fountains of this type have been surveyed in Pompeii, to gather information on their supply and its variation in time. A new method was devised for calculating the discharge through the overflow channel of each lacus, and this value was taken as an estimate of the water supplied to each fountain. The overflow channel internal cross-section width was measured at four elevations, and the cross-section profile was reconstructed based on these data. Three water levels of 1 cm, half of the cross-section height and entire cross section height, were considered at each channel’s inlet, obtaining a corresponding channel discharge. The values obtained, ranging from 0.03 to 2.9 l/s, were checked against the trajectory of the fountain water jet, making sure that it remained within the basin length. For 28 fountains the average discharge was found to be 0.08 l/s when the water was at the lowest level, 0.43 l/s for the intermediate level and 1.18 l/s for a full inlet. The average time of residence of the water, in the lacus draw basin, was estimated between 11 min and 3 h. An estimate of the demand of all the town lacus was compared with the capacity of the aqueduct channel entering at Porta Vesuvio: the town lacus could have been supplied contemporaneously at the minimum and intermediate discharges.

UJI TERAP PEMBANGKIT LISTRIK TENAGA AIR SKALA PICOHYDRO DI KABUPATEN BANJARNEGARA

This study aims to determine the technical application of picohydro power plant (making design and application test) in Pandansari Village, Wanayasa District, Banjarnegara Regency. The result of technical analysis of picohydro power plant is capable of producing 7.200 watt or 7,2 kilowatts of electric power. Based on the observation and calculation of water discharge in July-August 2017, the water debit required to run the generator on picohydro power plant is insufficient (less than 30 liters / sec) due to the months already entering the dry season in Banjarnegara Regency and also because some of the water debit is used by waterwheel to increase water supply to the water container / reservoir belonging to the people of Pandansari Village. During the dry season, the picohydro power plant can be used when operated alternately with a water mill or set the time of use for each water mill used in the morning until late afternoon, while the picohydro power plant is used during the afternoon until night or early morning when people need electricity for their daily needs. The next alternative is to place a second picohydro / turbine generator under the first turbine utilizing waste water from the first turbine with a height difference of at least 2 meters or more. If during the rainy season, there is a very heavy flow of water from above then the overflow can be disbursed / dumped down through the overflow channel so that the performance of the picohydro generator is not disturbed

Odonata larvae associated with the root system of eichhornia crassipes (pontederiaceae), in the chalons dam, Santiago de Cuba, Cuba

Were studied the Odonata’s larvae associated with the root system of Eichhornia crassipes (Mart. Solms) in two localities of the “Chalons”, dam overflow channel locate in Santiago de Cuba, from March 2005 to March 2006. For the Odonata’s larvae in the root system was determining the taxonomic composition and the trophic structure. A Spatial-temporal species group was estimated by the density of individuals and taxa, calculating the total volume by the method of root cone volume. In the study were collected 19 species belonging to four families. The temporal variation was correlated with the rainfall and the number of rainy days, according to Spearman Correlation. On the period of homogeneity of climatic variables the taxa’s and individuals’ density remained stable; however, the oscillations in the both densities were associated with the heterogeneity in the precipitation patterns. The densities of individual were different in both the sampled localities. The relationship between climatic variables, root volume and density of individuals suggests that the number of rainy days and accumulated rainfall influence in the abundance of certain taxa and that the roots of Eichhornia crassipes can be appraised as an important habitat for dragonflies larvae and a great place to find food for them.