Mississippi River nutrient loads and water stratification on the Louisiana-Texas shelf contribute to an annually recurring, short-lived hypoxic bottom layer in areas of the northern Gulf of Mexico comprising less than 2% of the total Gulf of Mexico bottom area. Many publications demonstrate increases in biomass and fisheries production attributed to nutrient loading from river plumes. Decreases...

several heavy metal resistant bacterial strains were isolated from sediment and water samples collected from the persian gulf and enclosed industrial areas. all the isolated bacteria were identified by 16s rrna gene sequencing. isolated bacteria were tested for the presence of plasmids using the modified alkaline lysate method. the method was effective for identification and characterization of...

Dead plant tissues and ash from a prescribed fire play an important role in nutrient balance and cycling in the Florida Everglades ecosystem. The objective of this study was to assess the dynamic changes in total phosphorus release (TPr) from ash or tissues of either cattail (Typha domingensis Pers.) or sawgrass (Cladium jamaicense Crantz) to water. Natural-dead (senesced-dead) and burning-dead...

The high strength carbon steels such as API X65 is widely used to build the pipelines. In this study, the corrosion behavior welds region of the gas pipeline was studied. For this purpose, Shield Metal Arc Welding (SMAW) was used to evaluate the proposed method. The welding processes were performed with E6010, E6013, and ER70S-6 electrodes as filler metal and welding carried out in 3 passes by ...

Bottom-blowing, as widely adopted in electric arc furnace (EAF) steelmaking technology, stir the molten bath by blowing inert gas (Ar, N2) from the bottom of EAF to promote fluid flow and uneven metallurgical reaction in the molten bath. However, for eccentric structure design of electric arc furnace, the problem still exists in EBT(Eccentric Bottom Tapping)area. In this study, by the analysis ...

A 3PRR parallel precision positioning system, driven by three ultrasonic linear motors, was designed for use as the object stage of a scanning electron microscope (SEM). To improve the tracking accuracy of the parallel platform, the positioning control algorithms for the drive joints needed to be studied. The deadzone phenomenon caused by static friction reduces the trajectory tracking accuracy...

This paper presents a compact cerebellar model articulation system for the position control of ultrasonic motors. Since the ultrasonic motors possess a time-variant and heavy nonlinearity and a variable dead-zone characteristic, it is difficult to create a precise model of ultrasonic motors. To overcome this problem, robust adaptive control technique is often utilized for the control of ultraso...