Macroscopic fundamental and Dirichlet strings have several potential instabilities: breakage, tachyon decays, and confinement by axion domain walls. We investigate the conditions under which metastable strings can exist, and we find that such strings are present in many models. There are various possibilities, the most notable being a network of (p, q) strings. Cosmic strings give a potentially...

One of the beneficial roles of riparian buffers is the capacity to attenuate groundwater nitrate before it can discharge to streams. Denitrification is one of the most important processes that permanently removes nitrate from groundwater; it requires anoxic conditions, a carbon source, and a suitable residence time as the reaction is microbially mediated. As denitrification rates are highly dep...

The objective of the study described in this article was to evaluate the nitrogen contributions from two onsite wastewater systems (sites 1 and 2) to groundwater and adjacent surface waters in coastal Beaufort County, North Carolina. Groundwater levels and water quality parameters including total nitrogen, nitrogen species, temperature, and pH were monitored from October 2009 to May 2010. Nitro...

1. introduction inflation of population and rising living standards in many countries need to be enhanced the high quality water suitable for different uses such as agricultural, industrial and drinking sections. groundwater is one of the most important water supply sources which are encountered with many problems such as drawdown, recharge reduction due to low rainfall and different natural an...

As a developing country, protecting groundwater resources is extremely essential in Sri Lanka. Landfills are one of the main sources of water pollution. The filling of the Gohagoda disposal yard, takes place at a distance about 50m from Gohagoda water intake plant. In addition, there is several boreholes located close proximity of the landfill, which used for drinking and domestic purposes. A s...

The long-term interest in nuclear fusion using tokamaks has yielded many published reactor designs. This study performs the first meta-analysis of tokamak reactor designs in an attempt to unveil new understanding not available in the traditional bottom-up method of looking at each design individually. Forty tokamak designs intended to produce significant fusion power at gains above one were ide...

The study of the groundwater resources and their properties are very important due to the vast desert areas and arid conditions. Given the current situation in Iran, the water supply is one of the most important territorial and environmental problems. In this study, groundwater resources were surveyed and mapped in Yazd Province and their properties were modeled to determine their effectiveness...

Application of over-winter green cover (e.g. cover crops) as a measure for reducing nitrate losses from tillage land has been frequently investigated, especially in the unsaturated zone. Monitoring of groundwater is less common in these studies. Studies on groundwater responses to different land treatments can be challenging because they can be influenced by various conditions, such as recharge...