Electron capture detector (ECD). Electron capture detectors (ECD) are typically used in environmental testing for detecting PCBâs, organochlorine pesticides, herbicides and various halogenated hydrocarbons. With an electron capture detector, a beta emitter such as radioactive tritium or 63Ni is used to ionize the carrier gas.
Las Piedras: Las Piedras, city, southern Uruguay. It is situated in a wine-growing district just north of Montevideo. It was the site of a decisive battle (1811) in Uruguayâs struggle for independence, in which the revolutionaries defeated Spanish forces. Las Piedras is among the largest cities in Uruguay. It is known for its ostrich farming and horse racing. Las Piedras is on the main highway and railroad linking Montevideo with TacuarembÃ³ and Rivera. Pop.
Black piedra and white piedra. Piedra, meaning stone in Spanish, is an asymptomatic fungal infection of the hair shaft, resulting in the formation of nodules of different hardness on the infected hair.hite and black piedra should be distinguished from each other. It can be noted that black piedra as compared to white piedra, presents a harder nodule that adheres to the hair shaft. Piedra can often be confused with pediculosis or lice infestation.