Study on removal of Se(IV) using Fe-Mn layered double hydroxides and Fe-Mn Dos (double oxides)

In this study, Fe-Mn-CO3 layered double hydroxide (LDHs) and Fe-Mn Double oxide (DOs) were synthesized by the co-recipitation methods for Se(IV) removal from aqueous solutions. The Se(IV) adsorption capacities and removal mechanism of Fe-Mn LDH and Fe-Mn DOs determined by batch and column experiments. The calculated Se(IV) adsorption capacities on Fe-Mn LDH and Fe-Mn DOs were 52.5 and 55.3 mg/g, respectively. Kinetic models applied to the adsorption of Se(IV) on the Fe-Mn LDH and Fe-Mn DOs calculated using pseudo-first, second-order, Elovich, and Intraparticle diffusion kinetic models and all kinetic parameters were calculated and discussed. Isotherm studies were also performed using Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich equations in the temperature range of 283 - 323 K. Adsorption kinetics and isotherm experiments are well fitted pseudo-second order model and Freundlich isotherm, respectively. The production of this adsorbent is cost-effective for industrial applications

Effect of Anticipatory Shooting Strategy on Performance Consistency in Skilled Elite Archer

PURPOSE This study examined the effect of anticipatory control strategies on stable upright posture and consistency in archery performance among skilled elite archers. METHODS Nine skilled archery players participated in this study and performed repeated shooting trials under two different shooting conditions: clicker and non-clicker. In the clicker condition, archers shot in response to clicker signals, whereas in the non-clicker condition, they used an anticipatory strategy to determine shooting time in a self-paced manner without using the clicker. A motion capture system with six infrared cameras was used to measure the coordinates of the bow and archers’ hands, which were then used to calculate the aiming precision index and draw-related variables. Electromyography of the lower leg muscles and the center of pressure (COP) were also analyzed for a short period immediately before release to determine the differences in anticipatory postural adjustments (APAs) between the two shooting conditions. RESULTS The non-clicker condition resulted in a relatively short drawing duration and better precision index. The COP speed rapidly increased immediately before the release (i.e., APAs), and the rate of increase was lower in the non-clicker condition than in the clicker shooting condition. Furthermore, smaller APAs were significantly correlated with better-aiming precision in the non-clicker condition. CONCLUSION These findings suggest that using an anticipatory strategy rather than reacting to a clicker can improve archery performance consistency by reducing APA and ensuring a stable shooting posture. This strategy can be used in archery training to predict clicker signals during the aim-release stage

Immobilization of Lead in Contaminated Firing Range Soil Using Biochar

Soybean stover-derived biochar was used to immobilize lead (Pb) in military firing range soil at a mass application rate of 0 to 20 wt.% and a curing period of 7 days. The toxicity characteristic leaching procedure (TCLP) was performed to evaluate the effectiveness of the treatment. The mechanism responsible for Pb immobilization in military firing range soil was evaluated by scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX) and x-ray absorption fine structure (XAFS) spectroscopy analyses. The treatment results showed that TCLP Pb leachability decreased with increasing biochar content. A reduction of over 90 % in Pb leachability was achieved upon treatment with 20 wt.% soybean stover-derived biochar. SEM-EDX, elemental dot mapping and XAFS results in conjunction with TCLP leachability revealed that effective Pb immobilization was probably associated with the pozzolanic reaction products, chloropyromorphite and Pb-phosphate. The results of this study demonstrated that soybean stover-derived biochar was effective in immobilizing Pb in contaminated firing range soil

How to Protect ADS-B: Con- fidentiality Framework and Efficient Realization Based on Staged Identity-Based Encryption

Automatic Dependent Surveillance-Broadcast (ADS-B) is one of the key technologies for future “e-Enabled” air crafts. ADS-B uses avionics in the e-Enabled aircrafts to broadcast essential flight data such as call sign, altitude, heading, and other extra positioning information. On the one hand, ADS-B brings significant benefits to the aviation industry, but, on the other hand, it could pose security concerns as channels between ground controllers and aircrafts for the ADS-B communication are not secured, and ADS-B messages could be captured by random individuals who own ADS-B receivers

Entangled iodine and hydrogen peroxide formation in ice

Ice-core records show that anthropogenic pollution has increased the global atmospheric concentrations of hydrogen peroxide and iodine since the mid-20th century. Here, for the first time, we demonstrate a highly efficient mechanism that synergistically produces them in icy water conditions. This reaction is aided by a key intermediate IO2H, formed by an I(-)ion with a dissolved O(2)in acidic icy water, which produces both I as well as O2H radicals. I recombines with I(-)to produce I(2)(-)at a diffusion-limited rate, followed by formation of I(3)(-)through disproportionation, while O2H yields H(2)O(2)with I(-)and a proton dissolved in icy water.11Nsciescopu

A Generalized Model for Transport of Contaminants in Soil by Electric Fields

A generalized model applicable to soils contaminated with multiple species under enhanced boundary conditions during treatment by electric fields is presented. The partial differential equations describing species transport are developed by applying the law of mass conservation to their fluxes. Transport, due to migration, advection and diffusion, of each aqueous component and complex species are combined to produce one partial differential equation hat describes transport of the total analytical concentrations of component species which are the primary dependent variables. This transport couples with geochemical reactions such as aqueous equilibrium, sorption, precipitation and dissolution. The enhanced model is used to simulate electrokinetic cleanup of lead and copper contaminants at an Army Firing Range. Acid enhancement is achieved by the use of adipic acid to neutralize the basic front produced for the cathode electrochemical reaction. The model is able to simulate enhanced application of the process by modifying the boundary conditions. The model showed that kinetics of geochemical reactions, such as metals dissolution/leaching and redox reactions might be significant for realistic prediction of enhanced electrokinetic extraction of metals in real world applications