297 research outputs found
Investigation of Pulsed Electrolysis for Hypochlorous Acid Production
Because of the Covid-19 pandemic along with the delay in the worldwide supply chain, there were disinfectant shortages that lasted for weeks around the world. Therefore, on-site production is a promising solution to satisfy the increasing demand. As more and more people are shifting toward safer and more environmentally friendly products, we are interested in investigating the electrolysis of sodium chloride (NaCl) solution to produce hypochlorous acid (HOCl). Electrolysis is inexpensive as it requires only sodium chloride and electricity, and it does not have any negative impact on the environment. Moreover, electrolysis can be coupled with renewable energy to utilize the excess energy that is hard to store. Meanwhile, hypochlorous acid was proven to be 80-100 times more effective than sodium hypochlorite, commonly known as bleach. Hypochlorous acid was also shown to be a non-toxic, anti-inflammatory, and non-corrosive disinfectant. Since electrolysis is an energy-intensive process, this project will study if using a pulsed direct current to perform electrolysis can improve the current efficiency or electricity requirements of the process. There was evidence showing that pulsed electrolysis was able to improve the electrolysis efficiency because of the reduction of bubbles coverage, perturbation of the electrical double layer, and enhancement of mass transportation. A flow-through reactor was made with a cathode made from titanium and an anode made from titanium coated with mixed metal oxide (a mixture of Iridium oxide and Tantalum oxide). The squared-shaped pulsed current was generated by utilizing MOSFET. The results showed that pulsed electrolysis increased the number of electrons converted into final products up to 10% more. Pulsed electrolysis also reduced the electricity requirement by 10%-15%. However, it significantly increased the need for sodium chloride because there was no reaction during the off-time. There are several proposed methods to minimize this disadvantage, but more experiments need to be done to assess them. Nevertheless, in the current density range from 2000 to 4500 A/m2, for the same amount of supplied power, pulsed electrolysis with a duty cycle of 80% required less sodium chloride to produce 1 kg of Cl2 than conventional constant electrolysis. Although frequency only affected the electrolysis efficiency slightly, operating at the optimized frequency extended the improvement of the pulsed electrolysis compared to the constant electrolysis. Utilizing pulsed electrolysis with the optimized settings can effectively decrease the operating cost of producing disinfectant (hypochlorous acid)
U.S. Coast Guard Boat Recovery Simulation at NASA Ames Vertical Motion Simulator
The Boat Recovery Simulation was a collaboration between the U.S. Coast Guard and NASA. The experiment was conducted at the NASA Ames Vertical Motion Simulator (VMS). The goals were to (1) design a VMS experiment that can accurately simulate the motion of high sea conditions and to (2) collect data for the U.S. Coast Guard on human performance related to small boat recovery operations. The experiment setup included a software operation model designed around empirical boat position data; a replica boat section manufactured to incorporate real-world task elements; and the means to collect objective and subjective data from human participants. The VMS provided a viable testbed to assess certified U.S. Coast Guard crewmembers task performance while in motion
Calculations of He+p elastic scattering cross sections using folding approach and high-energy approximation for the optical potential
Calculations of microscopic optical potentials (OP's) (their real and
imaginary parts) are performed to analyze the He+p elastic scattering data
at a few tens of MeV/nucleon (MeV/N). The OP's and the cross sections are
calculated using three model densities of He. Effects of the regularization
of the NN forces and their dependence on nuclear density are investigated.
Also, the role of the spin-orbit terms and of the non-linearity in the
calculations of the OP's, as well as effects of their renormalization are
studied. The sensitivity of the cross sections to the nuclear densities was
tested and one of them that gives a better agreement with the data was chosen.Comment: 13 pages, 11 figures, to be published in Eur. Phys. J.
What Explains Vietnam's Exceptional Performance in Education Relative to Other Countries? Analysis of the Young Lives Data from Ethiopia, Peru, India and Vietnam
Vietnam’s strong performance on the 2012 and 2015 PISA assessments has led to interest in what explains the strong academic performance of Vietnamese students. Analysis of the PISA data has not shed much light on this issue. This paper analyses a much richer data set, the Young Lives data for Ethiopia, India (Andhra Pradesh and Telangana), Peru and Vietnam, to investigate the reasons for the strong academic performance of 15-year-olds in Vietnam. Differences in observed child and household characteristics explain 37-39 percent of the gap between Vietnam, and Ethiopia, while observed school variables explain only about 3-4 additional percentage points (although an important variable, math teachers’ pedagogical skills, is not available for Ethiopia). Differences in observed child and household characteristics explain very little of the gaps between Vietnam and India and between Vietnam and Peru, yet one observed school variable has a large explanatory effect: primary school math teachers’ pedagogical skills. It explains about 10-12 percent of the gap between Vietnam and India, raising the overall explained portion to 14-21 percent of the gap. For Peru, it explains most (65-84 percent) of the gap
Encouraging Dialogue around Social Issues with Latinx Students Through Literature Discussion and Culturally Relevant Literature
This teacher research study examines literature discussions with fourth and fifth grade Latinx students about books that reflect Latinx experiences. For this study, the following questions are explored (1) What social issues do students discuss in literature groups? (2) How do literary response strategies influence student dialogue? And (3) How does my theoretical frame influence my decision making as a teacher?
Theories that informed the construction of the literature discussions and the decision making occurring throughout the study are examined closely. The theories intertwine and bridge education and students’ experiences as a resource in learning more about the educational setting. In this study, the discussions of students and the literature response strategies are explored as the data is analyzed to examine the student discussions around issues of immigration, family separation, borders, and so much more.
The findings in this study indicate that the experiences of Latinx students are integral to the educational setting and an education that invites who they are enhances their learning experiences. Latinx students are eager for learning opportunities that invite their voices and stories. It is through the construction and assessment of the educational setting that educators can promote culturally responsive, relevant, and sustaining teaching experiences that go beyond the classroom setting. Latinx students build relationships with each other and their teachers as they engage in discussions that allow them to share and learn with each other. This study is a reminder of the crucial role teachers play in creating such powerful spaces and the value that Latinx students bring into the classroom when invited to discuss, engage, and create powerful learning experiences
Recent progress constraining the nuclear equation of state from astrophysics and heavy ion reactions
The quest for the nuclear equation of state (EoS) at high densities and/or
extreme isospin is one of the longstanding problems of nuclear physics. Ab
initio calculations for the nuclear many-body problem make predictions for the
density and isospin dependence of the EoS far away from the saturation point of
nuclear matter. On the other hand, in recent years substantial progress has
been mode to constrain the EoS both, from the astrophysical side and from
accelerator based experiments. Heavy ion experiments support a soft EoS at
moderate densities while recent neutron star observations require a ``stiff''
high density behavior. Both constraints are discussed and shown to be in
agreement with the predictions from many-body theory.Comment: Invited talk given at NPA III, Dresden, Germany, March 200
Defect-engineered metal-organic frameworks (MOF-808) towards the improved adsorptive removal of organic dyes and chromium (vi) species from water
In this work, two defective zirconium-based metal-organic frameworks (Zr-MOFs), MOF-808-OH and MOF-808-NH2, were synthesized by partially replacing the 1,3,5-benzenetricarboxylate building block with 5-hydroxyisophthalate and 5-aminoisophthalate, respectively. The structural features of the defective materials were analyzed by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), nitrogen physisorption at 77 K, and thermogravimetric analysis (TGA). Importantly, the number of defect sites determined via proton nuclear magnetic resonance (1H-NMR) analysis of the digested materials was approximately 7 mol% for MOF-808-OH and 3 mol% for MOF-808-NH2. The presence of the defect sites increased the number of acidic centers on Zr-clusters originating from missing-linker nodes which accounted for a remarkable adsorption capacity towards various anionic organic dyes and chromium (vi) species. Compared to standard MOF-808, the defect-engineered ones showed significant increments by 30-60% in trapping capacity for anionic contaminants including sunset yellow, quinoline yellow, methyl orange, and potassium dichromate, while they exhibited modest improvements by 5-15% in the removal of cationic dyes, namely malachite green and methylene blue
Few-Shot Object Detection via Synthetic Features with Optimal Transport
Few-shot object detection aims to simultaneously localize and classify the
objects in an image with limited training samples. However, most existing
few-shot object detection methods focus on extracting the features of a few
samples of novel classes that lack diversity. Hence, they may not be sufficient
to capture the data distribution. To address that limitation, in this paper, we
propose a novel approach in which we train a generator to generate synthetic
data for novel classes. Still, directly training a generator on the novel class
is not effective due to the lack of novel data. To overcome that issue, we
leverage the large-scale dataset of base classes. Our overarching goal is to
train a generator that captures the data variations of the base dataset. We
then transform the captured variations into novel classes by generating
synthetic data with the trained generator. To encourage the generator to
capture data variations on base classes, we propose to train the generator with
an optimal transport loss that minimizes the optimal transport distance between
the distributions of real and synthetic data. Extensive experiments on two
benchmark datasets demonstrate that the proposed method outperforms the state
of the art. Source code will be available
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