Chemistry Commons^™

Recycling Aluminum, Steffani Burwitz, Kristin M. Roe, Matthew L. Miller, Madhav P. Nepal, Larry B. Browning, P. Troy White

Madhav Nepal

Students will investigate and compare the energy cost to produce aluminum products from aluminum ore and recycled aluminum. Students will perform an electrolysis activity to reinforce the idea that recycling metal requires less energy than mining and refining metals from their original source in the earth.

Building Data And Information Literacy In The Undergraduate Chemistry Curriculum, Yasmeen Shorish, Barbara A. Reisner

Yasmeen Shorish

The Literature and Seminar sequence at James Madison University has been used to develop the chemistry information literacy skills of chemistry majors for over four decades. These courses have been continually updated to emphasize information literacy skills for the twenty-first century. This chapter describes the methods that have been developed to improve chemical, data and general information literacy at a large, public, primarily undergraduate institution. The focus of the first semester course, described in this chapter, is on skill building rather than teaching specific resources. It is a model of integration and collaboration between chemistry faculty and chemistry librarians. Changes …

What Students Think And How They Really Perform In Chemistry, Ross Hudson

Dr Ross Hudson

This research was part of a larger study into student performance in senior chemistry with regard to question type and content. This paper examines student perceptions about question type and context and compares these perceptions to actual performance. How students perceive different types of questions and how it influences their self-belief and motivation were the focus of this study. Student responses to different styles or types of questions have been well researched over time. In this study Year 11 chemistry students were quizzed about their preferences to Multiple-Choice questions and Open Response question types and how the presence of each …

Revised Plan For Institutionalizing Undergraduate Research At Kenyon College, Kerry Rouhier, Dan Hartnett, Jan Kmetko, Joe Murphy

Kerry A Rouhier

No abstract provided.

A Comparison Of Student Perceptions To Actual Performance In Chemistry, Ross Hudson

Dr Ross Hudson

This research was part of a larger study into student performance in senior chemistry with regard to question type and content. This paper examines student perceptions about question type and context and compares these perceptions to actual performance. How students perceive different types of questions and how it influences their self-belief and motivation were the focus of this study. Student responses to different styles or types of questions have been well researched over time. In this study Year 11 chemistry students were quizzed about their preferences to Multiple-Choice questions and Open Response question types and how the presence of each …

Developing Transfer Skills In A Biochemistry Class, Jeong V. Choe

Jeong Choe

Students seem to struggle with transferring prior knowledge if the new problem they are given is in a different form from the way they learned the material. The process of transfer can be identified by four components: 1) recognizing the similarity between the old and new contexts; 2) identifying the potential of a certain skill or concept that has worked in the past, to give solutions to new problematic situations; 3) mental testing of the application of the potential solution; and 4) an attempt to apply the skill or concept to a new context (Georghiades 2000). These four components are …

Integrated Mathematica™-Based Physical Chemistry Curriculum: Bringing The Science To The Forefront, Kevin Ausman

Kevin D. Ausman

Undergraduate- and graduate-level physical chemistry classes are often so mathematically intensive that they often (a) dissuade qualified students from pursuing the field, (b) require more homework, testing, and grading time be devoted to tracking down hidden mathematical errors than is devoted to working with the subject matter, and (c) limit the complexity, and therefore real-world applicability, of assigned problems. In this talk, the integration of the general-purpose mathematical tool MathematicaTM throughout the second semester of undergraduate physical chemistry will be discussed. Examples provided will demonstrate the feasibility of introducing the MathematicaTM language gradually over the course of the semester, allowing …

Measurements Of Nh3 Linestrengths And Collisional Broadening Coefficients In N2, O2, Co2, And H2o Near 1103.46 Cm−1, Kyle Owen, Et-Touhami Es-Sebbar, Aamir Farooq

Dr. Et-touhami Es-sebbar

Laser-based ammonia gas sensors have useful applications in many fields including combustion, atmospheric monitoring, and medical diagnostics. Calibration-free trace gas sensors require the spectroscopic parameters including linestrengths and collisional broadening coefficients to be known. Ammonia's strong ν2 vibrational band between View the MathML source has the high absorption strength needed for sensing small concentrations. Within this band, the 1103.46 cm−1 feature is one of the strongest and has minimal interference from CO2 and H2O. However, the six rotational transitions that make up this feature have not been studied previously with absorption spectroscopy due to their small line spacing ranging from …

Effects Of N2o And O2 Addition To Nitrogen Townsend Dielectric Barrier Discharges At Atmospheric Pressure On The Absolute Ground-State Atomic Nitrogen Density, Et. Es-Sebbar, N. Gherardi, F. Massines

Dr. Et-touhami Es-sebbar

Absolute ground-state density of nitrogen atoms N (2p3 4S3/2) in non-equilibrium Townsend dielectric barrier discharges (TDBDs) at atmospheric pressure sustained in N2/N2O and N2/O2 gas mixtures has been measured using Two-photon absorption laser-induced fluorescence (TALIF) spectroscopy. The quantitative measurements have been obtained by TALIF calibration using krypton as a reference gas. We previously reported that the maximum of N (2p3 4S3/2) atom density is around 3 × 1014 cm−3 in pure nitrogen TDBD, and that this maximum depends strongly on the mean energy dissipated in the gas. In the two gas mixtures studied here, results show that the absolute N …

Inhibition Of Bacillus Cereus Growth By Bacteriocin Producing Bacillus Subtilis Isolated From Fermented Baobab Seeds (Maari) Is Substrate Dependent, Donatien Kaboré, Dennis S. Nielsen, Hagrétoui Sawadogo-Lingan, Bréhima Diawara, Mamoudou H. Dicko Prof., Mogens Jakobsen, Line Thorsen

Pr. Mamoudou H. DICKO, PhD

Temperature-Dependent Absorption Cross-Section Measurements Of 1-Butene (1-C4h8) In Vuv And Ir, Et-Touhami Es-Sebbar, Yves Benilan, Aamir Farooq

Dr. Et-touhami Es-sebbar

Vacuum ultraviolet (VUV) and infrared (IR) absorption cross-section measurements of 1-butene (1-C4H8; CH2=CHCH2CH3; Butylene) are reported over the temperature range of 296–529 K. The VUV measurements are performed between 115 and 205 nm using synchrotron radiation as a tunable VUV light source. Fourier Transform Infrared (FTIR) spectroscopy is employed to measure absorption cross-section and band strengths in the IR region between 1.54 and 25 μm (∼6500–400 cm−1). The measured room-temperature VUV and IR absorption cross-sections are compared with available literature data and are found to be in good agreement. The oscillator strength for the electronic transition (A1A′→X1A′) around 150–205 nm …

Comparison Of Phenolic Compounds And Antioxidant Capacities Of Traditional Sorghum Beers With Other Alcoholic Beverages, Fatouma Abdoul-Latif, Romaric G. Bayili, Louis C. Obame, Mamoudou H. Dicko Prof.

Pr. Mamoudou H. DICKO, PhD

Thirty samples of sorghum beers “dolo” were selected from traditionally fermented household manufacturers from Burkina Faso. Dolo samples were screened for their total phenolic content, proanthocyanidins and putative antioxidant capacities, and were compared with industrial beers and wines. Total phenols were measured using the Folin-Ciocalteu method. Proanthocyanidins content were determined by the method of HCl-butanol hydrolysis. Antioxidant activities were evaluated both with 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and by the trolox equivalent antioxidant capacity (TEAC) using 2,2’-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid radical) (ABTS•+). The average contents of total phenols and proanthocyanidins were 506 μg GAE/ml of dolo and 45 μg APE/ml of dolo, respectively. An …

Toxicity Assessment And Analgesic Activity Investigation Of Aqueous Acetone Extracts Of Sida Acuta Burn F. And Sida Cordifolia L. (Malvaceae), Medicinal Plants Of Burkina Faso, Kiessoum Konate, Adama Hilou, Raïssa Rr Aworet-Samseny, Alain Souza, Nicolas Barro, Mamoudou H. Dicko Prof., Jacques Datté, Bertrand M’Batchi

Pr. Mamoudou H. DICKO, PhD

Background Sida acuta Burn f. and Sida cordifolia L. (Malvaceae) are traditionally used in Burkina Faso to treat several ailments, mainly pains, including abdominal infections and associated diseases. Despite the extensive use of these plants in traditional health care, literature provides little information regarding their toxicity and the pharmacology. This work was therefore designed to investigate the toxicological effects of aqueous acetone extracts of Sida acuta Burn f. and Sida cordifolia L. Furthermore, their analgesic capacity was assessed, in order to assess the efficiency of the traditional use of these two medicinal plants from Burkina Faso. Method For acute toxicity …

Capacitively Coupled Radio-Frequency Discharges In Nitrogen At Low Pressures, L. L Alves, L. Marques, C. D Pintassilgo, W. Wattieaux, Et. Es-Sebbar, J. Berndt, E. Kovačević, N. Carrasco, L. Boufendi, G. Cernogora

Dr. Et-touhami Es-sebbar

This paper uses experiments and modelling to study capacitively coupled radio-frequency (rf) discharges in pure nitrogen, at 13.56 MHz frequency, 0.1–1 mbar pressures and 2–30 W coupled powers. Experiments performed on two similar (not twin) setups, existing in the LATMOS and the GREMI laboratories, include electrical and optical emission spectroscopy (OES) measurements. Electrical measurements give the rf-applied and the direct-current-self-bias voltages, the effective power coupled to the plasma and the average electron density. OES diagnostics measure the intensities of radiative transitions with the nitrogen second-positive and first-negative systems, and with the 811.5 nm atomic line of argon (present as an …

Antibacterial Activity Against Beta- Lactamase Producing Methicillin And Ampicillin-Resistants Staphylococcus Aureus: Fractional Inhibitory Concentration Index (Fici) Determination, Kiessoun K Onate, Jacques François Mavoungou, Alexis Nicaise Lepengué, Raïssa Rr Aworet-Samseny, Adama Hilou, Mamoudou H. Dicko Prof., Bertrand M’Batchi

Pr. Mamoudou H. DICKO, PhD

The present study reports the antibacterial capacity of alkaloid compounds in combination with Methicillin and Ampicillin-resistants bacteria isolated from clinical samples. The resistance of different bacteria strains to the current antibacterial agents, their toxicity and the cost of the treatment have led to the development of natural products against the bacteria resistant infections when applied in combination with conventional antimicrobial drugs. The antibacterial assays in this study were performed by using inhibition zone diameters, MIC, MBC methods, the time-kill assay and the Fractional Inhibitory Concentration Index (FICI) determination. On the whole, fifteen Gram-positive bacterial strains (MRSA/ARSA) were used. Negative control …

Ionization Photophysics And Rydberg Spectroscopy Of Diacetylene, M. Schwell, Y. Benilan, N.. Fray, M.-C. Gazeau, Et. Es-Sebbar, F.-G. Levrel, N. Campion, S. Leach

Dr. Et-touhami Es-sebbar

Photoionization of diacetylene was studied using synchrotron radiation over the range 8–24 eV, with photoelectron-photoion coincidence (PEPICO) and threshold photoelectron–photoion coincidence (TPEPICO) techniques. Mass spectra, ion yields, total and partial ionization cross-sections were measured. The adiabatic ionization energy of diacetylene was determined as IEad = (10.17 ± 0.01) eV, and the appearance energy of the principal fragment ion C4H+ as AE = (16.15 ± 0.03) eV. Calculated appearance energies of other fragment ions were used to infer aspects of dissociation pathways forming the weaker fragment ions , C3H+, and C2H+. Structured autoionization features observed in the PEPICO spectrum of diacetylene …

Volatile Products Controlling Titan’S Tholins Production, N. Carrasco, T. Gautier, Et. Es-Sebbar, P. Pernot, G. Cernogora

Dr. Et-touhami Es-sebbar

A quantitative agreement between nitrile relative abundances and Titan’s atmospheric composition was recently shown with a reactor simulating the global chemistry occurring in Titan’s atmosphere [Gautier et al. (2011) Icarus, 213: 625]. Here we present a complementary study on the same reactor using an in-situ diagnostic of the gas phase composition. Various initial N2-CH4 gas mixtures (methane varying from 1 to 10%) are studied, with a monitoring of the methane consumption and of the stable gas neutrals by in-situ mass spectrometry. Atomic hydrogen is also measured by optical emission spectroscopy. A positive correlation is found between atomic hydrogen abundance and …

Excellent Adventures In Global Collaboration, Glenn W. "Max" Mcgee, Aracelys Rios

Glenn W. "Max" McGee

No abstract provided.

Bacteriocin Formation By Dominant Aerobic Sporeformers Isolated From Traditional Maari, Donatien Kabore, Line Thorsen, Dennis Sandris Nielsen, Torben Sune Berner, Hagrétou Sawadogo-Lingani, Bréhima Diawara, Mamoudou H. Dicko Prof., Mogens Jackobsen

Pr. Mamoudou H. DICKO, PhD

The antimicrobial activity of 8 Bacillus spp. and 2 Lysinibacillus spp. representing the predominant aerobic sporeformers during traditional maari fermentations, a traditional fermented baobab seeds product fromBurkina Faso,was investigated. The antimicrobial activitywas assessed against a total of 31 indicator organisms representing various Gram-negative and positive pathogens. The screening showed that 3 Bacillus subtilis strains (B3, B122 and B222) in particular had antimicrobial activity against some Gram-positive organisms and were selected for further studies. Itwas found that the antimicrobial substances producedwere heat stable, in-sensitive to catalase, sensitive to protease and trypsin but resistant to the proteolytic action of papain and proteinase …

Vuv Photoionization Of Acetamide Studied By Electron / Ion Coincidence Spectroscopy In The 8-24 Ev Photon Energy Range, M. Schwell, Y. Bénilan, N. Fray, M.-C Gazeau, Et. Es-Sebbar, Gustavo A. Garcia, L. Nahon, N. Champion, S. Leach

Dr. Et-touhami Es-sebbar

A VUV photoionization study of acetamide was carried out over the 8-24 eV photon energy range using synchrotron radiation and photoelectron/photoion coincidence (PEPICO) spectroscopy. Threshold photoelectron photoion coincidence (TPEPICO) measurements were also made. Photoion yield curves and branching ratios were measured for the parent ion and six fragment ions. The adiabatic ionization energy of acetamide was determined as I.E (12A’) = (9.71±0.02) eV, in agreement with an earlier reported photoionization mass spectrometry (PIMS) value. The adiabatic energy of the first excited state of the ion, 12A”, was determined to be ≈ 10.1 eV. Assignments of the fragment ions and the …

Acid Resistance, Bile Tolerance And Antimicrobial Properties Of Dominant Lactic Acid Bacteria Isolated From Traditional “Maari” Baobab Seeds Fermented Condiment, Donatien Kabore, Hagrétou Sawadogo-Lingani, Mamoudou H. Dicko Prof., Bréhima Diawara, Mogens Jacobsen

Pr. Mamoudou H. DICKO, PhD

Maari is a fermented food condiment obtained by spontaneous fermentation of seeds from the baobab tree (Adansonia digitata). Nine dominant lactic acid bacteria (LAB) strains, isolated from traditional maari fermentation were examined for their resistance to pH 2.5, their tolerance to 0.3% bile and their antimicrobial activities against pathogenic bacteria. The agar spot test was used to screen the dominant LAB for antagonistic activity against a total of 21 indicator organisms including Bacillus cereus strains, Salmonella spp., Listeria monocytogenes, Yersinia enterocolitica, Escherichia coli and Micrococcus luteus. It was observed that all LAB strains survived in 0.3% bile and exhibited antimicrobial …

Extractive Metallurgy Of Copper, Fathi Habashi

Fathi Habashi

Parallel Text Immersion, Daniel P. Becker Ph.D.

Daniel P. Becker

A new method of teaching foreign languages to beginning, intermediate, and advancing foreign language students is proposed involving reading out loud passages, chapters, and entire works of literature that are familiar to the student through required pre-reading in the students’ mother tongue. Testing is proposed to evaluate the success of the method.

A Review Of Baobab (Adansonia Digitata) Products: Effect Of Processing Techniques, Medicinal Properties And Uses, Donatien Kabore, Hagrétou Sawadogo-Lingani, Bréhima Diawara, Clarise Compaoré, Mamoudou H. Dicko Prof., Mogens Jacobsen

Pr. Mamoudou H. DICKO, PhD

A general literature review including the effect of processing techniques, medicinal value and uses of baobab tree is reported in this manuscript. Baobab tree has multi-purpose uses, as it produces food and non-food products such as medicines, fuel, timber, fodder. Every part of the baobab tree is reported to be useful. The seeds, leaves, roots, flowers, fruit pulp and bark of baobab are edible. Baobab leaves are used in the preparation of soup. Seeds are used as a thickening agent in soups, but they can be fermented and used as a flavouring agent or roasted and eaten as snacks. The …

Vuv Absorption Cross Section Of Benzene, Relevance For Titan’S Atmosphere, F-J. Capalbo, Y. Bénilan, N. Fray, M. Schwell, Et. Es-Sebbar, N. Champion, T. Koskinen, R. Yelle

Dr. Et-touhami Es-sebbar

Saturn's largest satellite, Titan, is the only one in the Solar System known to have a thick N2/CH4, planet like atmosphere. The dissociation of these principal components and the recombination of the products make this atmosphere to be rich in organic compounds of high interest for astrobiology. Solar and stellar occultations observed by the Ultraviolet Imaging Spectrograph (UVIS) on board the Cassini spacecraft can be used to characterize the composition of Titan’s upper atmosphere (400 – 1400 km). The results depend strongly on the knowledge of the molecular absorption cross sections of the atmospheric constituents (Ferradaz et al. 2009). This …

Antimicrobial And Antioxidant Activities Of Essential Oil And Methanol Extract Of Matricaria Chamomilla L. From Djibouti, Fatouma M. Abdoul-Latif, Mohamed Nabil, Prosper Edou, Adwa A. Ali, Samatar O. Djama, Louis-Clément Obamé, Mamoudou H. Dicko Prof.

Pr. Mamoudou H. DICKO, PhD

The essential oil and methanol extracts of Matricaria Chamomilla L. were subjected to screening for their possible antioxidant activity by two complementary test systems, namely 2,2-diphenykpicrylhydrazyl (DPPH) free radical scavenging and β-carotene-linoleic acid assays. BHT was used as positive control in both test systems. In the DPPH test system, the IC50 values of essential oil and methanol extracts were 4.18 and 1.83 μg/ml, respectively. In the β-carotene-linoleic acid system, oxidation was effectively inhibited by M. Chamomilla, the RAA value of essential oil and methanol extracts were 12.69 and 11.37 %, respectively. When compared to BHT, the essential oil and methanol …

Characterization Of Continuous Vacuum Ultraviolet Lamps-Implication On The Study Of Methane Photolysis At Lyman Alpha (121.6 Nm), M-C. Gazeau, Y. Benilan, Et. Es-Sebbar, A. Jolly, E. Arzoumanian, N. Fray, H. Cottin

Dr. Et-touhami Es-sebbar

Low-temperature hydrogen plasmas are widely used as continuous vacuum ultraviolet irradiation sources in photochemical studies and, in particular, in laboratory simulations of planetary atmospheres. One of the most challenging objectives of such experiments is to retrieve accurate quantitative laboratory data allowing a reliable comparison with theoretical and/or observational ones. This task can only be achieved when the irradiation source delivers a well characterised radiation in terms of flux and wavelength dependency. As an example, we will present a study, developed in the frame of a program dedicated to simulations of Titan’s atmosphere, on methane photolysis at Lyman alpha (121.6 nm). …

Formation Of Hcn And Nh3 As Primary Compounds Of Titan’S Atmosphere Simulations Using N2-Ch4 Afterglow Plasma’’, M-C. Gazeau, Y. Bénilan, E. Arzoumanian, Et. Es-Sebbar, A. Jolly, C.D. Pintassilgo

Dr. Et-touhami Es-sebbar

No abstract provided.

Biodepollution Of Wastewater Containing Phenolic Compounds From Leather Industry By Plant Peroxidases, Mamounata Diao, Nafissetou Ouedraogo, Lamine Baba-Moussa, Paul W. Savadogo, Georges N'Guessan Amani, Mamoudou H. Dicko Prof.

Pr. Mamoudou H. DICKO, PhD

This study deals with the use of peroxidases (POXs) from Allium sativum, Ipomoea batatas, Raphanus sativus and Sorghum bicolor to catalyze the degradation of free phenolic compounds as well as phenolic compounds contained in wastewater from leather industry. Secretory plant POXs were able to catalyze the oxidation of gallic acid, ferulic acid, 4-hydroxybenzoic acid, pyrogallol and 1,4-tyrosol prepared in ethanol 2% (v:v). Efficiency of peroxidase catalysis depends strongly on the chemical nature of phenolic substrates and on the botanical source of the enzymes. It appeared that POX from Raphanus sativus had the highest efficiency. Results show that POXs can also …

Absolute Ground-State Nitrogen Atom Density In A N2/Ch4 Late Afterglow: Talif Experiments And Modelling Studies, Et. Es-Sebbar, M.-C. Gazeau, Y. Benilan, A. Jolly, C D. Pintassilgo

Dr. Et-touhami Es-sebbar

Following a first study on a late afterglow in flowing pure nitrogen post discharge, we report new two-photon absorption laser-induced fluorescence (TALIF) measurements of the absolute ground-state atomic nitrogen density N(4S) and investigate the influence of methane introduced downstream from the discharge by varying the CH4 mixing ratio from 0% up to 50%. The N (4S) maximum density is about 2.2 × 1015 cm−3 in pure N2 for a residence time of 22 ms and does not change significantly for methane mixing ratio up to ~15%, while above, a drastic decrease is observed. The influence of the residence time has …