A catalytic reactor for the trapping of free radicals from gas phase oxidation reactions

A catalytic reactor for the trapping of free radicals originating from gas phase catalytic reactions is described and discussed. Radical trapping and identification were initially carried out using a known radical generator such as dicumyl peroxide. The trapping of radicals was further demonstrated by investigating genuine radical oxidation processes, e.g., benzaldehyde oxidation over manganese and cobalt salts. The efficiency of the reactor was finally proven by the partial oxidation of cyclohexane over MoO3, Cr2O3, and WO3, which allowed the identification of all the radical intermediates responsible for the formation of the products cyclohexanol and cyclohexanone. Assignment of the trapped radicals was carried out using spin trapping technique and X -band electron paramagnetic resonance spectroscopy. © 2010 American Institute of Physics.

Optical trapping with superfocused high-M2 laser diode beam

Many applications of high-power laser diodes demand tight focusing. This is often not possible due to the multimode nature of semiconductor laser radiation possessing beam propagation parameter M2 values in double-digits. We propose a method of 'interference' superfocusing of high-M2 diode laser beams with a technique developed for the generation of Bessel beams based on the employment of an axicon fabricated on the tip of a 100 μm diameter optical fiber with highprecision direct laser writing. Using axicons with apex angle 140º and rounded tip area as small as 10 μm diameter, we demonstrate 2-4 μm diameter focused laser 'needle' beams with approximately 20 μm propagation length generated from multimode diode laser with beam propagation parameter M2=18 and emission wavelength of 960 nm. This is a few-fold reduction compared to the minimal focal spot size of 11 μm that could be achieved if focused by an 'ideal' lens of unity numerical aperture. The same technique using a 160º axicon allowed us to demonstrate few-μm-wide laser 'needle' beams with nearly 100 μm propagation length with which to demonstrate optical trapping of 5-6 μm rat blood red cells in a water-heparin solution. Our results indicate the good potential of superfocused diode laser beams for applications relating to optical trapping and manipulation of microscopic objects including living biological objects with aspirations towards subsequent novel lab-on-chip configurations.

Optical trapping with Bessel beams generated from semiconductor lasers

In this paper, we study generation of Bessel beams from semiconductor lasers with high beam propagation parameter M2 and their utilization for optical trapping and manipulation of microscopic particles including living cells. The demonstrated optical tweezing with diodegenerated Bessel beams paves the way to replace their vibronic-generated counterparts for a range of applications towards novel lab-on-a-chip configurations.

Optical trapping with Bessel beams generated from semiconductor lasers

In this paper, we demonstrate, for the first time to the best of our knowledge, utilization of Bessel beams generated from a semiconductor laser for optical trapping and manipulation of microscopic particles including living cells. © 2014 OSA.

Local Energy Decay in Even Dimensions for the Wave Equation with a Time-Periodic Non-Trapping Metric and Applications to Strichartz Estimates

2000 Mathematics Subject Classification: 35B40, 35L15.

Impact of high microwave power on hydrogen impurity trapping in nanocrystalline diamond films grown with simultaneous nitrogen and oxygen addition into methane/hydrogen plasma

In this work, we study for the first time the influence of microwave power higher than 2.0 kW on bonded hydrogen impurity incorporation (form and content) in nanocrystalline diamond (NCD) films grown in a 5 kW MPCVD reactor. The NCD samples of different thickness ranging from 25 to 205 μm were obtained through a small amount of simultaneous nitrogen and oxygen addition into conventional about 4% methane in hydrogen reactants by keeping the other operating parameters in the same range as that typically used for the growth of large-grained polycrystalline diamond films. Specific hydrogen point defect in the NCD films is analyzed by using Fourier-transform infrared (FTIR) spectroscopy. When the other operating parameters are kept constant (mainly the input gases), with increasing of microwave power from 2.0 to 3.2 kW (the pressure was increased slightly in order to stabilize the plasma ball of the same size), which simultaneously resulting in the rise of substrate temperature more than 100 °C, the growth rate of the NCD films increases one order of magnitude from 0.3 to 3.0 μm/h, while the content of hydrogen impurity trapped in the NCD films during the growth process decreases with power. It has also been found that a new H related infrared absorption peak appears at 2834 cm-1 in the NCD films grown with a small amount of nitrogen and oxygen addition at power higher than 2.0 kW and increases with power higher than 3.0 kW. According to these new experimental results, the role of high microwave power on diamond growth and hydrogen impurity incorporation is discussed based on the standard growth mechanism of CVD diamonds using CH4/H2 gas mixtures. Our current experimental findings shed light into the incorporation mechanism of hydrogen impurity in NCD films grown with a small amount of nitrogen and oxygen addition into methane/hydrogen plasma.

Trapping and unlimited delay of light pulses at microscale without distortion

A tunable bottle microresonator can trap an optical pulse of the given spectral width, hold it as long as the material losses permit, and release without distortion.

Evaluation of contact and non-contact trapping efficiencies of human scent chemical profiles and their stabilities under different environmental conditions

Establishing an association between the scent a perpetrator left at a crime scene to the odor of the suspect of that crime is the basis for the use of human scent identification evidence in a court of law. Law enforcement agencies gather evidence through the collection of scent from the objects that a perpetrator may have handled during the execution of the criminal act. The collected scent evidence is consequently presented to the canines for identification line-up procedures with the apprehended suspects. Presently, canine scent identification is admitted as expert witness testimony, however, the accurate behavior of the dogs and the scent collection methods used are often challenged by the court system. The primary focus of this research project entailed an evaluation of contact and non-contact scent collection techniques with an emphasis on the optimization of collection materials of different fiber chemistries to evaluate the chemical odor profiles obtained using varying environment conditions to provide a better scientific understanding of human scent as a discriminative tool in the identification of suspects. The collection of hand odor from female and male subjects through both contact and non-contact sampling approaches yielded new insights into the types of VOCs collected when different materials are utilized, which had never been instrumentally performed. Furthermore, the collected scent mass was shown to be obtained in the highest amounts for both gender hand odor samples on cotton sorbent materials. Compared to non-contact sampling, the contact sampling methods yielded a higher number of volatiles, an enhancement of up to 3 times, as well as a higher scent mass than non-contact methods by more than an order of magnitude. The evaluation of the STU-100 as a non-contact methodology highlighted strong instrumental drawbacks that need to be targeted for enhanced scientific validation of current field practices. These results demonstrated that an individual's human scent components vary considerably depending on the method used to collect scent from the same body region. This study demonstrated the importance of collection medium selection as well as the collection method employed in providing a reproducible human scent sample that can be used to differentiate individuals.

White-nose syndrome initiates a cascade of physiologic disturbances in the hibernating bat host

Acknowledgments This project was financially supported by the US Geological Survey through a cooperative agreement with the University of Wisconsin – Madison. We are indebted to Dave and Jennifer Redell and Paul White from the Wisconsin Department of Natural Resources for collecting the animals used to complete this study and for assisting with data collection. We thank Melissa Behr for assistance with necropsies and NWHC Animal Care Staff for their help with set-up and maintenance of animals. We thank Lobke Vaanholt and Catherine Hambly (University of Aberdeen, Scotland) for their expertise and coordination in the analyses of the DLW blood samples. Funds were used for direct project costs only. Use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the US Government.

Laboratory Investigation of Diluted Bitumen Trapping and Dissolution in Gravel

The Canadian economy is largely dependent on the distribution of large volumes of oil to domestic and international markets by a long network of pipelines. Unfortunately, accidents occur, and oil can leak or spill from these pipelines before it reaches its destination. Of particular concern are the long-term consequences of oil spills in freshwater, which include sinking of oil in water and the contamination of sensitive areas, such as where fish (e.g., salmon) deposit their eggs in gravel-dominated river sediments. There is a knowledge gap regarding the fate and behaviour of oil in river sediment. To this end, this study aimed at finding the potential for diluted bitumen (dilbit) oil to become trapped in gravel and to transfer hydrocarbons into water by dissolution, which are harmful to aquatic life. Two sets of laboratory experiments were conducted to simulate conditions of an oil spill on an exposed bank or in shallow water. In the first set, by conducting capillary pressure-saturation (Pc-Sw) experiments it was found that dilbit can enter gravel pores without much resistance and approximately 14% of the pore volume can be occupied by discontinuous single or multipore blobs of dilbit following imbibition of water. Air-water Pc-Sw experiments done in laboratory 1-D columns required gravity correction and could be successfully scaled to predict dilbit-water Pc-Sw curves, except for the trapped amount of dilbit. Trapped dilbit constituents can be dissolved into the water flowing through gravel pores (hyporheic flow) at different velocities. In the second set, dissolution experiments suggested that for the duration of the test, hydrocarbons that cause acute toxicity dissolve rapidly, likely resulting in a decrease in their effective solubility. However, dilbit saturation changed only <2% within that time. Chronically toxic PAH compounds were also detected in the effluent water. The total concentration of all detected PAHs and alkylPAHs exceeded the threshold literature value to protect early-life stage fish. Observations of decreased concentrations with increased aqueous velocities as well as less than equilibrium concentrations indicated that the mass transfer was rate-limited. A correlation was developed for the mass transfer rate coefficient to understand the mass transfer behaviour beyond the conditions used in the experiments, which had a Reynolds number exponent similar to the studies of NAPL dissolution in groundwater.

It’s a Trap! Unravelling Reversible Charge Trapping in Nanocrystals Through Single Particle and Ensemble Studies

Thesis (Ph.D.)--University of Washington, 2016-08

Iowa Hunting and Trapping Regulations, 2016-2017

This booklet is not a complete set of hunting laws. It contains basic information needed during the hunting and trapping seasons.