Examining the use of computer simulations to promote learning of electrochemistry among college students

When computer simulations are popular in helping students understand chemistry in today\u27s classrooms, it is important to realize how instructional use of computer simulations affects students\u27 understanding of science. This dissertation centers around the impact of the use of computer simulations on college students\u27 learning. Chapter 1 generally addresses the background and the significance of the research topics. Chapter 2 reviews the literature from research that studied the factors that affect the use of computer simulations in helping students learn science. Learners were found to understand science theories better with descriptions and explanations presented in both verbal and visual formats than in verbal format alone. An individual\u27s prior knowledge and learning strategies have also been found to have an impact on her/his response to computer simulations and therefore affect the potential value of computer simulations. Chapter 3 reveals the impact of the use of computer simulations on students\u27 understanding of electrochemistry principles. The results confirm findings in earlier studies that college students seemed to be able to build mental models of chemical reactions from formula and equations with or without the help of computer simulations. The study in Chapter 3 indicates that it is likely that the design of the learning activities rather than the use of technology actually had an impact on students learning. Chapter 4 provides insights into how the use of simulations affected the communication between group members and how individuals with different levels of prior knowledge responded to computer programs and interacted with peers. Although prior knowledge was not found to interact with the use of computer simulations in affecting students\u27 understanding, the findings in Chapter 4 show that prior knowledge seemed to affect the ways that students solved problems and the ways they interacted with the computer simulations.;Taken together, these three studies in this dissertation suggest continuing research needs to be done in identifying and resolving issues when individual differences are considered. In addition, it is important that the design of learning activities be given a higher level of priority than the use of instructional technology when employing computer simulations in the classrooms

Natural Nanoporous Filter Material as a New High-Efficiency Natural Adsorbent to Remove Textile Dyes

The objective of this paper is to perform the innovation design of removing most textile dyes that are harmful to the environment and might induce cancer. However, many methodologies had been developed for various chemical and physical processes to remove different dyes, such as ozone oxidation, electrochemical methods, chemical coagulation, hypochlorite oxidation, and adsorption to remove dyes from wastewater. A novel nanoporous filter methodology and mathematic simulations for adsorption were established as an effective medium for removing dyes from wastewater which was compared to other expensive treatments. The different concentrations of the dye liquid are used as a tester, and the different concentrations of nanoporous adsorbent were added in a uniform distribution and were tested with different time courses and under different temperatures. The final readings were measured by a spectrophotometer and fit into a mathematic model. The result indicates that this nanoporous and natural adsorbents are very good at cleaning the dyes in this system. The fit-in mathematic models could be applied in these tests which can be used in the industrial conditions for a low cost without secondary dye pollutions

The Study of Natural Nano-Composite Filter for Industrial Wastewater Treatment

Due to the rapid development of industry, the amount of industrial wastewater and water pollution is a serious problem for environment. Along with the economic development, the complications of wastewater treatment and drainage have been raised. For examples, textile printing and dyeing wastewater as model system, we utilized natural nano-composite filter adsorption test under different concentrations of dye liquid, different times with nano-composite powder, and observed the solutions with spectrophotometer. The manufacture of natural nano-composite filter was from a variety of mineral flour in accordance with the specific proportion of ore combination, and its inside appearance was like a sponge structure with many nano-sized pores, which increased its adsorption capacity. The production procedure of this natural nano-composite was much simpler than activated carbon, and the failure rate is relatively low, so the cost is lower twice than functional activated carbon. Because it is made of natural mineral powder, it will not cause second pollution to the environment. The final results show that methylene blue and no.257 black dye adsorption capacity of natural nano-composite filter was more effective in high temperature 55℃. Conclusively, we used the absorption curves to demonstrate the absorption kinetics

Fabrication and Photovoltaic Characteristics of Coaxial Silicon Nanowire Solar Cells Prepared by Wet Chemical Etching

Nanostructured solar cells with coaxial p-n junction structures have strong potential to enhance the performances of the silicon-based solar cells. This study demonstrates a radial junction silicon nanowire (RJSNW) solar cell that was fabricated simply and at low cost using wet chemical etching. Experimental results reveal that the reflectance of the silicon nanowires (SNWs) declines as their length increases. The excellent light trapping was mainly associated with high aspect ratio of the SNW arrays. A conversion efficiency of ∼7.1% and an external quantum efficiency of ∼64.6% at 700 nm were demonstrated. Control of etching time and diffusion conditions holds great promise for the development of future RJSNW solar cells. Improving the electrode/RJSNW contact will promote the collection of carries in coaxial core-shell SNW array solar cells

Clinical Outcome of Mycobacterium abscessus Infection and Antimicrobial Susceptibility Testing

Background/PurposeMycobacterium abscessus is the most resistant and rapidly growing mycobacterium and causes a wide range of clinical infectious diseases. The relationship between antimicrobial susceptibility and clinical outcome needs to be further evaluated.MethodsForty M. abscessus isolates were obtained from clinical specimens of 40 patients at the Taichung Veterans General Hospital from January 2006 to December 2008. Antimicrobial susceptibility testing was performed using the broth microdilution method according to the recommendations of the National Committee for Clinical Laboratory Standards. The clinical manifestations and outcomes were reviewed from medical records.ResultsTwenty-two patients were diagnosed with M. abscessus infection. Cough (86.3%), hemoptysis (31.8%) and fever (18.1%) were the most common symptoms. The radiographic findings included reticulonodular opacities (50.0%), consolidation (31.8%) and cavitary lesions (18.1%). The 40 isolates were susceptible to amikacin (95.0%), cefoxitin (32.5%), ciprofloxacin (10.0%), clarithromycin (92.5%), doxycycline (7.5%), imipenem (12.5%), moxifloxacin (22.5%), sulfamethoxazole (7.5%) and tigecycline (100%). The rate of treatment failure was 27.3% at the end of the 12th month after the start of treatment, although these patients were treated with a combination of clarithromycin and other antimicrobial agents.ConclusionM. abscessus is naturally susceptible to clarithromycin and amikacin, variably susceptible to cefoxitin and imipenem, and resistant to most other antimicrobial drugs. Combination therapy with clarithromycin, amikacin and other active antimicrobial agents may lead to clinical improvement; however, the rate of treatment failure is still high

Written and spoken corpus of real and fake social media postings about COVID-19

This study investigates the linguistic traits of fake news and real news. There are two parts to this study: text data and speech data. The text data for this study consisted of 6420 COVID-19 related tweets re-filtered from Patwa et al. (2021). After cleaning, the dataset contained 3049 tweets, with 2161 labeled as 'real' and 888 as 'fake'. The speech data for this study was collected from TikTok, focusing on COVID-19 related videos. Research assistants fact-checked each video's content using credible sources and labeled them as 'Real', 'Fake', or 'Questionable', resulting in a dataset of 91 real entries and 109 fake entries from 200 TikTok videos with a total word count of 53,710 words. The data was analysed using the Linguistic Inquiry and Word Count (LIWC) software to detect patterns in linguistic data. The results indicate a set of linguistic features that distinguish fake news from real news in both written and speech data. This offers valuable insights into the role of language in shaping trust, social media interactions, and the propagation of fake news.Comment: 9 pages, 3 table

Atomic Bose-Einstein condensate in a twisted-bilayer optical lattice

Observation of strong correlations and superconductivity in twisted-bilayer-graphene have stimulated tremendous interest in fundamental and applied physics. In this system, the superposition of two twisted honeycomb lattices, generating a Moir$\acute{\mathrm{e}}$ pattern, is the key to the observed flat electronic bands, slow electron velocity and large density of states. Despite these observations, a full understanding of the emerging superconductivity from the coupled insulating layers and the appearance of a small magic angle remain a hot topic of research. Here, we demonstrate a quantum simulation platform to study superfluids in twisted bilayer lattices based on Bose-Einstein condensates loaded into spin-dependent optical lattices. The lattices are made of two sets of laser beams that independently address atoms in different spin states, which form the synthetic dimension of the two layers. The twisted angle of the two lattices is controlled by the relative angle of the laser beams. We show that atoms in each spin state only feel one set of the lattice and the interlayer coupling can be controlled by microwave coupling between the spin states. Our system allows for flexible control of both the inter- and intralayer couplings. Furthermore we directly observe the spatial Moir$\acute{\mathrm{e}}$ pattern and the momentum diffraction, which confirm the presence of atomic superfluid in the bilayer lattices. Our system constitutes a powerful platform to investigate the physics underlying the superconductivity in twisted-bilayer-graphene and to explore other novel quantum phenomena difficult to realize in materials.Comment: 6 pages, 5 figure