Comparative study: Correlating extraction efficiency for Hg(II), Cd(II), and Pb(II) metal ions with the chelate stability and total hardness in simple nitrogen donors

Four N-donors (PHDA, ATPH, APHO, and MTAN) containing NH₂ were used to extract Hg(II), Cd(II), and Pb(II). Their extraction capacity was determined by measurement of percentage extraction.

The chelates extract these metals differently: for example, efficiency of ATPH was the highest for Hg(II) compared to PHDA, APHO, and MTAN.

The extraction efficiency was found to depend on: donor atom hardness, chelate total hardness, metal: chelate mole ratio and substituent’s electronic effects. Among all, total hardness and chelate stability are key factors and molecule of small (E_HOMO – E_LUMO) is more reactive, where extraction efficiency increases as molecular stability decreases.     

On the development of a confocal Rayleigh-Brillouin microscope

This Note illustrates how a confocal microscope may be modified to conduct Rayleigh-Brillouin mapping experiments that yield very useful information on the mechanical properties of interfacial materials in small volume elements. While the modifications to the microscope are quite straightforward, they do entail significant changes in the optical design. The instrument described herein consists of an argon ion laser equipped with an actively stabilized intercavity etalon that serves as the excitation source for a modified Zeiss LSM 310 confocal laser scan microscope. The optics of the microscope were reconfigured to enable interfacing of the microscope with a tandem triple-pass Fabry-Perot interferometer. This instrument enables three-dimensional Rayleigh-Brillouin spectral mapping of samples at micron spatial resolution. The performance of the instrument and its ability to perform both lateral and depth scans of the acoustic phonon velocity and, hence, the longitudinal modulus across bonded polymer/polymer and polymer/ceramic interfaces are illustrated and discussed.     

Comparison of the performance of vulcanized rubbers and elastomer/TPE/iron composites for less lethal ammunition applications

One of the exciting novel potential applications of thermoplastic elastomers (TPEs) is less‐lethal ammunition (LLA). The importance of LLA in crowd control and law enforcement has been acknowledged, and became evident for air marshals after the September 11, 2001 crisis. This article will compare the dynamic mechanical behavior of various elastomer/TPE/iron composites and commercially available LLA based on conventional cured rubbers (ethylene‐propylene‐diene rubber [EPDM], styrene‐butadiene rubber [SBR], and natural rubber [NR]). Optimum combination of properties for LLA application was shown by the poly(styrene‐b‐isobutylene‐b‐styrene) (SIBS)/butyl elastomer (IIR)/iron 50/50/233 composite. POLYM. ENG. SCI., 45:966–975, 2005. © 2005 Society of Plastics Engineers     

A proposed technique for power extraction from acoustic energy scavenging

In this study, converting acoustic to electric energy was achieved via the Disk Jockey (DJ) model TG5000, which worked as a noise source, and the piezoelectric model 7BB-41–2, which worked as a transducer. We proposed different states of piezoelectric transducer’s mounting on DJ and examined the results to determine the optimum state for maximization of the converted power. We proposed a technique which comprises four stages, and each stage is composed of a piezoelectric transducer followed by a voltage multiplier. The outputs of the four stages were connected in parallel, and these transducers were mounted via their bodies on the slim diaphragm of the acoustic focusing tube. The results indicated that the maximum converted power values were 1.225 mW with a load resistor of 10 kΩ for one stage, 1.089 mW with a load resistor of 10 kΩ for two stages, 1.682 mW with a load resistor of 5 kΩ for three stages, and 5.891mW with a load resistor of 2.2 kΩ for four stages at a sound intensity level of 85 dB and sound wave frequency of 2.1 kHz.     

Sweeping filters and tooth rotation energy estimation (TREE) techniques for machine tool condition monitoring

This paper presents a method for the condition monitoring of the milling cutting process based upon a combination of two techniques; sweeping filters and tooth rotation energy estimation (TREE). Existing spindle speed and spindle load signals from the machine are used thus avoiding the need for any additional sensors. The sweeping filter technique determines the frequency components of the spindle signal using low cost hardware. The filter's cut off frequency is swept across a range of frequencies and its output is acquired and analysed in real time. The variations of individual tooth energies estimated by the TREE technique in the time domain are used to verify the results. The hybrid approach created is based on the verification of any indicated faults before making a final conclusion about the health of the cutting tool. This provides a robust and reliable tool monitoring system that is able to identify tool breakage in real time during machining operations.     

160 Gb/s photonic crystal semiconductor optical amplifier-based all-optical logic NAND gate

The performance of an ultra-fast all-optical logic NOT-AND gate using photonic crystal semiconductor optical amplifiers (PCSOA)-based Mach–Zehnder interferometers is numerically analysed and investigated. The dependence of the quality factor (Q-factor) on the input signals’ and PCSOA operating parameters is examined, with the impact of amplified spontaneous emission included so as to obtain realistic results. The achieved Q-factor is 18 at 160 Gb/s, which is higher than when using conventional SOAs.     

Realization of ultrafast all-optical NAND and XNOR logic functions using carrier reservoir semiconductor optical amplifiers

The Journal of Supercomputing - The conventional SOA suffers from the problem of the finite gain recovery time that limits its application at higher data rates. Therefore, in the present paper, we...     

Water, Food, and Energy Security: An Elusive Search for Balance in Central Asia

The development and use of water resources in the Amu Darya Basin remain under debate in the face of increasing population and associated scarcities in water, food, and energy. The upstream riparian, the mountain nation of Tajikistan, wishes to develop its hydropower potential. Three downstream states wish to sustain or increase their economic benefits from water used for irrigation. Growing tensions among the riparian countries on the Vakhsh River, a tributary of Amu Darya, have halted development of Tajikistan’s proposed Rogun Dam. This paper examines the potential for mutually beneficial water development and allocation of water resources to sustain demands for water, food, and energy. Using long-term data on the Basin’s energy potential, water supplies, irrigated land, and crop water demands, this paper analyzes total economic welfare for a future 20-year time horizon. Two water supply scenarios for each of two policy choices are examined. Results show that a constrained economic optimization operation of the Dam has the potential to increase farm income for each riparian country, while producing considerable benefits in hydropower for Tajikistan. Political negotiation among the riparian states and much better data will be needed to discover and implement potential gains indicated by this study.     

Filter orthogonal frequency-division multiplexing scheme based on polar code in underwater acoustic communication with non-Gaussian distribution noise

The research domain of underwater communication has garnered much interest among researchers exploring underwater activities. The underwater environment differs from the terrestrial setting. Some of the main challenges in underwater communication are limited bandwidth, low data rate, propagation delay, and high bit error rate (BER). As such, this study assessed the underwater acoustic (UWA) aspect and explored the expression of error performance based on t-distribution noise. Filter orthogonal frequency-division multiplexing refers to a new waveform candidate that has been adopted in UWA, along with turbo and polar codes. The empirical outcomes demonstrated that the noise did not adhere to Gaussian distribution, whereas the simulation results revealed that the filter applied in orthogonal frequency-division multiplexing could significantly suppress out-of-band emission. Additionally, the performance of the turbo code was superior to that of the polar code by 2 dB at BER 10⁻³.     

Effect of neutron dose on the structural properties of Makrofol polycarbonate

The effect of neutron dose on the structural properties of a Makrofol polycarbonate detector has been studied. Samples of Makrofol were classified into three main groups. The first, second and third groups were irradiated with neutrons in the dose ranges of 0.01-0.08, 0.1-0.8 and 1.0-8.0 Sv, respectively. The structural modifications in the neutron irradiated samples were studied using X-ray diffraction and Fourier-transform infrared spectroscopy. In addition, the effect of neutron dose on the intrinsic viscosity of the liquid samples, as a measure of the mean molecular mass of the Makrofol polymer, was studied. An increase in the -OH groups was observed at dose ranges of 0.01-0.04 and 3.21-8.0 Sv due to the degradation of carbonate group and the -H abstraction from the polymer backbone to form hydroxyl groups. This indicates that the degradation is dominant at these dose ranges that enhance the degree of ordering in the irradiated samples. On the other hand, irradiation in the dose range 0.04-3.21 Sv was characterized by a dominant crosslinking mechanism that led to an increase of the amorphous phase and average molecular mass.