CHEMISTRY OF DISSOLVED ORGANIC CARBON AT BEAR BROOK WATERSHED, MAINE: STREAM WATER RESPONSE TO (NH4)2SO4 ADDITIONS. (R825762)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

How Do Undergraduate Students Conceptualize Acid-Base Chemistry? Measurement of a Concept Progression

ERIC Educational Resources Information Center

Romine, William L.; Todd, Amber N.; Clark, Travis B.

2016-01-01

We developed and validated a new instrument, called "Measuring Concept progressions in Acid-Base chemistry" (MCAB) and used it to better understand the progression of undergraduate students' understandings about acid-base chemistry. Items were developed based on an existing learning progression for acid-base chemistry. We used the Rasch…

RESPONSE OF SURFACE WATER CHEMISTRY TO CHANGES IN ACIDIC DEPOSITION: IMPLICATIONS FOR THE UPCOMING DEBATE ON THE FEDERAL CLEAN AIR ACT. (R829095C004)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Reaction chemistry in rechargeable Li-O2 batteries.

PubMed

Lim, Hee-Dae; Lee, Byungju; Bae, Youngjoon; Park, Hyeokjun; Ko, Youngmin; Kim, Haegyeom; Kim, Jinsoo; Kang, Kisuk

2017-05-22

The seemingly simple reaction of Li-O 2 batteries involving lithium and oxygen makes this chemistry attractive for high-energy-density storage systems; however, achieving this reaction in practical rechargeable Li-O 2 batteries has proven difficult. The reaction paths leading to the final Li 2 O 2 discharge products can be greatly affected by the operating conditions or environment, which often results in major side reactions. Recent research findings have begun to reveal how the reaction paths may be affected by the surrounding conditions and to uncover the factors contributing to the difficulty in achieving the reactions of lithium and oxygen. This progress report describes the current state of understanding of the electrode reaction mechanisms in Li-O 2 batteries; the factors that affect reaction pathways; and the effect of cell components such as solvents, salts, additives, and catalysts on the discharge product and its decomposition during charging. This comprehensive review of the recent progress in understanding the reaction chemistry of the Li-O 2 system will serve as guidelines for future research and aid in the development of reliable high-energy-density rechargeable Li-O 2 batteries.

On Study of New Progress and Application of Coordination Chemistry in Chemistry and Chemical Industry in Recent Years

NASA Astrophysics Data System (ADS)

Zhang, Yunshen

2017-12-01

Coordination chemistry refers to a branch of chemistry, and its research results are widely used in industry and people's daily life. Many edge disciplines emerge during the development, which propels the process of disciplines and technology. This paper briefly discusses new progress of coordination chemistry and its application in chemistry and chemical industry in recent years.

Modelling alkali metal emissions in large-eddy simulation of a preheated pulverised-coal turbulent jet flame using tabulated chemistry

NASA Astrophysics Data System (ADS)

Wan, Kaidi; Xia, Jun; Vervisch, Luc; Liu, Yingzu; Wang, Zhihua; Cen, Kefa

2018-03-01

The numerical modelling of alkali metal reacting dynamics in turbulent pulverised-coal combustion is discussed using tabulated sodium chemistry in large eddy simulation (LES). A lookup table is constructed from a detailed sodium chemistry mechanism including five sodium species, i.e. Na, NaO, NaO2, NaOH and Na2O2H2, and 24 elementary reactions. This sodium chemistry table contains four coordinates, i.e. the equivalence ratio, the mass fraction of the sodium element, the gas-phase temperature, and a progress variable. The table is first validated against the detailed sodium chemistry mechanism by zero-dimensional simulations. Then, LES of a turbulent pulverised-coal jet flame is performed and major coal-flame parameters compared against experiments. The chemical percolation devolatilisation (CPD) model and the partially stirred reactor (PaSR) model are employed to predict coal pyrolysis and gas-phase combustion, respectively. The response of the five sodium species in the pulverised-coal jet flame is subsequently examined. Finally, a systematic global sensitivity analysis of the sodium lookup table is performed and the accuracy of the proposed tabulated sodium chemistry approach has been calibrated.

Laboratory and Theoretical Studies of Tropospheric Iodine Chemistry (Invited)

NASA Astrophysics Data System (ADS)

Plane, J. M.; Saunders, R. W.; Kumar, R.; Gomez Martin, J.; Mahajan, A. S.; Murray, B. J.

2009-12-01

This paper will discuss progress in understanding two important properties of iodine in the marine boundary layer: ozone depletion and new particle formation. A variety of laboratory techniques have been employed to study the kinetics and growth of iodine oxide particles, their uptake of water, sulphuric and organic acids, and the recyling of iodine from them. The photochemistry of a variety of iodine oxides, which are central to catalytic O3 depletion and are involved in homogeneous condensation, will also be described. The use of high-level quantum chemistry calculations to underpin these experiments will then be discussed. Finally, the implications of this work for understanding the impact of iodine in both remote and polluted marine environments will be considered.

Biomarkers of Renal Tumor Burden and Progression in TSC

DTIC Science & Technology

2012-09-01

code) Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39.18 Biomarkers of Renal Tumor Burden and Progression in TSC Dr. Elahna Paul 1...appearance and growth rates) and renal function parameters (e.g. blood pressure, serum chemistries, urinalysis and urine chemistries). (2) Measure...and renal function parameters (e.g. blood pressure, serum chemistries, urinalysis and urine chemistries). (2) Measure soluble growth factors

Independent Study in High School Chemistry: A Progress Report.

ERIC Educational Resources Information Center

DeRose, James V.

This is a progress report of an independent study program in chemistry at a senior high school. Currently in its fourth year of operation, the program is designed to provide students with individualized, self-paced instruction in college-preparatory chemistry. The author discusses the rationale for the program, the initial phases, the problems…

High precision optical spectroscopy and quantum state selected photodissociation of ultracold 88Sr2 molecules in an optical lattice

NASA Astrophysics Data System (ADS)

McDonald, Mickey

2017-04-01

Over the past several decades, rapid progress has been made toward the accurate characterization and control of atoms, epitomized by the ever-increasing accuracy and precision of optical atomic lattice clocks. Extending this progress to molecules will have exciting implications for chemistry, condensed matter physics, and precision tests of physics beyond the Standard Model. My thesis describes work performed over the past six years to establish the state of the art in manipulation and quantum control of ultracold molecules. We describe a thorough set of measurements characterizing the rovibrational structure of weakly bound 88Sr2 molecules from several different perspectives, including determinations of binding energies; linear, quadratic, and higher order Zeeman shifts; transition strengths between bound states; and lifetimes of narrow subradiant states. Finally, we discuss measurements of photofragment angular distributions produced by photodissociation of molecules in single quantum states, leading to an exploration of quantum-state-resolved ultracold chemistry. The images of exploding photofragments produced in these studies exhibit dramatic interference effects and strongly violate semiclassical predictions, instead requiring a fully quantum mechanical description.

Chemistry Division. Quarterly progress report for period ending June 30, 1949

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1949-09-14

Progress reports are presented for the following tasks: (1) nuclear and chemical properties of heavy elements (solution chemistry, phase rule studies); (2) nuclear and chemical properties of elements in the fission product region; (3) general nuclear chemistry; (4) radio-organic chemistry; (5) chemistry of separations processes; (6) physical chemistry and chemical physics; (7) radiation chemistry; (8) physical measurements and instrumentation; and (9) analytical chemistry. The program of the chemistry division is divided into two efforts of approximately equal weight with respect to number of personnel, chemical research, and analytical service for the Laboratory. The various research problems fall into the followingmore » classifications: (1) chemical separation processes for isolation and recovery of fissionable material, production of radioisotopes, and military applications; (2) reactor development; and (3) fundamental research.« less

[The Journal de chimie médicale (Journal of Medical Chemistry) : a major innovation on French public health during the 19th century ].

PubMed

Bonnemain, Bruno

2017-03-01

JBA Chevallier is first known for his publication in 1850 of his book on falsifications. But he had also a major role for the opening of the pharmacy world to toxicological and Public Health issues, through the founding in 1825, and the management for more than 50 years, of the Journal de chimie médicale, de pharmacie et de toxicologie (Journal of Medical Chemistry, of Pharmacy and of Toxicology). The purpose of the present study has been to look at the evolution of that publication over the years and to compare its content with the reference pharmaceutical journal at that time : the Journal de pharmacie et de chimie (Journal of Pharmacy and Chemistry). One can observe that the editorial lines of both journals will progressively diverge from each other, but Chevallier remained strongly connected with pharmacy, his journal merging finally in 1876 with the Répertoire de pharmacie (Index of Pharmacy).

Progressive Transitions in Chemistry Teachers' Understanding of Nature of Science Based on Historical Controversies

ERIC Educational Resources Information Center

Niaz, Mansoor

2009-01-01

The objective of this study is to facilitate progressive transitions in chemistry teachers understanding of nature of science in the context of historical controversies. Selected controversies referred to episodes that form part of the chemistry curriculum both at secondary and university freshman level. The study is based on 17 in-service…

Exploring the Progression in Preservice Chemistry Teachers' Pedagogical Content Knowledge Representations: The Case of "Behavior of Gases"

ERIC Educational Resources Information Center

Adadan, Emine; Oner, Diler

2014-01-01

This multiple case study investigated how two preservice chemistry teachers' pedagogical content knowledge (PCK) representations of behavior of gases progressed in the context of a semester-long chemistry teaching methods course. The change in the participants' PCK components was interpreted with respect to the theoretical PCK learning…

Frontiers in Chemistry.

ERIC Educational Resources Information Center

Joyce, Robert M., Ed.

1980-01-01

This article describes recent progress in chemical synthesis which depends on comparable advances in other areas of chemistry. Analysis and theories of chemical structure and reactions are determinants in progress in chemical synthesis and are described also. (Author/SA)

Bioorthogonal chemistry: strategies and recent development

PubMed Central

Ramil, Carlo P.; Lin, Qing

2013-01-01

The use of covalent chemistry to track biomolecules in their native environment—a focus of bioorthogonal chemistry—has received considerable interests recently among chemical biologists and organic chemists alike. To facilitate wider adoption of bioorthogonal chemistry in biomedical research, a central effort in the last few years has been focused on the optimization of a few known bioorthogonal reactions, particularly with respective to reaction kinetics improvement, novel genetic encoding systems, and fluorogenic reactions for bioimaging. During these optimizations, three strategies have emerged, including the use of ring strain for substrate activation in the cycloaddition reactions, the discovery of new ligands and privileged substrates for accelerated metal-catalysed reactions, and the design of substrates with pre-fluorophore structures for rapid “turn-on” fluorescence after selective bioorthogonal reactions. In addition, new bioorthogonal reactions based on either modified or completely unprecedented reactant pairs have been reported. Finally, increasing attention has been directed toward the development of mutually exclusive bioorthogonal reactions and their applications in multiple labeling of a biomolecule in cell culture. In this feature article, we wish to present the recent progress in bioorthogonal reactions through the selected examples that highlight the above-mentioned strategies. Considering increasing sophistication in bioorthogonal chemistry development, we strive to project several exciting opportunities where bioorthogonal chemistry can make a unique contribution to biology in near future. PMID:24145483

A refuge for inorganic chemistry: Bunsen's Heidelberg laboratory.

PubMed

Nawa, Christine

2014-05-01

Immediately after its opening in 1855, Bunsen's Heidelberg laboratory became iconic as the most modern and best equipped laboratory in Europe. Although comparatively modest in size, the laboratory's progressive equipment made it a role model for new construction projects in Germany and beyond. In retrospect, it represents an intermediate stage of development between early teaching facilities, such as Liebig's laboratory in Giessen, and the new 'chemistry palaces' that came into existence with Wöhler's Göttingen laboratory of 1860. As a 'transition laboratory,' Bunsen's Heidelberg edifice is of particular historical interest. This paper explores the allocation of spaces to specific procedures and audiences within the laboratory, and the hierarchies and professional rites of passage embedded within it. On this basis, it argues that the laboratory in Heidelberg was tailored to Bunsen's needs in inorganic and physical chemistry and never aimed at a broad-scale representation of chemistry as a whole. On the contrary, it is an example of early specialisation within a chemical laboratory preceding the process of differentiation into chemical sub-disciplines. Finally, it is shown that the relatively small size of this laboratory, and the fact that after ca. 1860 no significant changes were made within the building, are inseparably connected to Bunsen's views on chemistry teaching.

Final Report: Rational Design of Anode Surface Chemistry in Microbial Fuel Cells for Improved Exoelectrogen Attachment and Electron Transfer

DTIC Science & Technology

2015-12-21

SECURITY CLASSIFICATION OF: The overall goal of this project is to determine how electrode surface chemistry can be rationally designed to decrease...2015 Approved for Public Release; Distribution Unlimited Final Report: Rational Design of Anode Surface Chemistry in Microbial Fuel Cells for...ABSTRACT Final Report: Rational Design of Anode Surface Chemistry in Microbial Fuel Cells for Improved Exoelectrogen Attachment and Electron Transfer

The physical chemistry and materials science behind sinter-resistant catalysts.

PubMed

Dai, Yunqian; Lu, Ping; Cao, Zhenming; Campbell, Charles T; Xia, Younan

2018-06-18

Catalyst sintering, a main cause of the loss of catalytic activity and/or selectivity at high reaction temperatures, is a major concern and grand challenge in the general area of heterogeneous catalysis. Although all heterogeneous catalysts are inevitably subjected to sintering during their operation, the immediate and drastic consequences can be mitigated by carefully engineering the catalytic particles and their interactions with the supports. In this tutorial review, we highlight recent progress in understanding the physical chemistry and materials science involved in sintering, including the discussion of advanced techniques, such as in situ microscopy and spectroscopy, for investigating the sintering process and its rate. We also discuss strategies for the design and rational fabrication of sinter-resistant catalysts. Finally, we showcase recent success in improving the thermal stability and thus sinter resistance of supported catalytic systems.

Indoor chemistry: research opportunities and challenges.

PubMed

Nazaroff, W W; Goldstein, A H

2015-08-01

In this editorial, we have highlighted key research opportunities and challenges in four topical themes for indoor chemistry: human occupants as agents influencing indoor chemistry; oxidative chemistry; surface phenomena; and semivolatile organic compounds. In each case, enough prior work has been done to demonstrate the importance of the theme and to create a foundation for future studies. Extensive achievements and ongoing progress in (outdoor) atmospheric chemistry—both in the analytical methods developed and in the scientific knowledge created—also contribute to a strong foundation from which to achieve rapid research progress in this exciting new domain.

Analytical Chemistry Division annual progress report for period ending December 31, 1985

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shultz, W.D.

1986-05-01

Progress reports are presented for the four major sections of the division: analytical spectroscopy, radioactive materials laboratories, inorganic chemistry, and organic chemistry. A brief discussion of the division's role in the Laboratory's Environmental Restoration and Facilities Upgrade is given. Information about quality assurance and safety programs is presented, along with a tabulation of analyses rendered. Publications, oral presentations, professional activities, educational programs, and seminars are cited.

Nebular chemistry and theories of lunar origin

NASA Technical Reports Server (NTRS)

Larimer, John W.

1986-01-01

The cosmic history of planetary matter is traced from nucleosynthesis through accretion in an attempt to understand the origin of the moon. It is noted that nebular processes must be considered in any theory of lunar origin and that planetary differentiation and volcanism determine the final character of lunar rocks. The moon's unique blend of nebular components suggests that the earth and moon accreted from the same mix of components as the proto-moon orbited the proto-earth, with the earth winning and the moon progressively losing, its solar complement of the components.

77 FR 64100 - Glycine from the People's Republic of China: Final Results of Antidumping Duty Administrative Review

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-18

... Mantong Fine Chemistry Co. Ltd. (Baoding Mantong), for the final results. \\1\\ See Glycine From the People... and the Preliminary Margin-Calculation Program for Baoding Mantong Fine Chemistry Co., Ltd.'' (Revised...) Baoding Mantong Fine Chemistry Co., Ltd 453.79 Assessment Rates Consistent with these final results, and...

Green Chemistry: Progress and Barriers

NASA Astrophysics Data System (ADS)

Green, Sarah A.

2016-10-01

Green chemistry can advance both the health of the environment and the primary objectives of the chemical enterprise: to understand the behavior of chemical substances and to use that knowledge to make useful substances. We expect chemical research and manufacturing to be done in a manner that preserves the health and safety of workers; green chemistry extends that expectation to encompass the health and safety of the planet. While green chemistry may currently be treated as an independent branch of research, it should, like safety, eventually become integral to all chemistry activities. While enormous progress has been made in shifting from "brown" to green chemistry, much more effort is needed to effect a sustainable economy. Implementation of new, greener paradigms in chemistry is slow because of lack of knowledge, ends-justify-the-means thinking, systems inertia, and lack of financial or policy incentives.

Progressive Transitions from Algorithmic to Conceptual Understanding in Student Ability To Solve Chemistry Problems: A Lakatosian Interpretation.

ERIC Educational Resources Information Center

Niaz, Mansoor

The main objective of this study is to construct models based on strategies students use to solve chemistry problems and to show that these models form sequences of progressive transitions similar to what Lakatos (1970) in the history of science refers to as progressive 'problemshifts' that increase the explanatory' heuristic power of the models.…

Reviving the lithium metal anode for high-energy batteries

NASA Astrophysics Data System (ADS)

Lin, Dingchang; Liu, Yayuan; Cui, Yi

2017-03-01

Lithium-ion batteries have had a profound impact on our daily life, but inherent limitations make it difficult for Li-ion chemistries to meet the growing demands for portable electronics, electric vehicles and grid-scale energy storage. Therefore, chemistries beyond Li-ion are currently being investigated and need to be made viable for commercial applications. The use of metallic Li is one of the most favoured choices for next-generation Li batteries, especially Li-S and Li-air systems. After falling into oblivion for several decades because of safety concerns, metallic Li is now ready for a revival, thanks to the development of investigative tools and nanotechnology-based solutions. In this Review, we first summarize the current understanding on Li anodes, then highlight the recent key progress in materials design and advanced characterization techniques, and finally discuss the opportunities and possible directions for future development of Li anodes in applications.

Ionic Liquids and Poly(ionic liquid)s for Morphosynthesis of Inorganic Materials.

PubMed

Gao, Min-Rui; Yuan, Jiayin; Antonietti, Markus

2017-04-24

Ionic liquids (ILs) are new, innovative ionic solvents with rich physicochemical properties and intriguing pre-organized solvent structures; these materials offer great potential to impact across versatile areas of scientific research, for example, synthetic inorganic chemistry. Recent use of ILs as precursors, templates, and solvents has led to inorganic materials with tailored sizes, dimensionalities, morphologies, and functionalities that are difficult to obtain, or even not accessible, by using conventional solvents. Poly(ionic liquid)s (PILs) polymerized from IL monomers also raise the prospect of modifying nucleation, growth, and crystallization of inorganic objects, shedding light on the synthesis of a wide range of new materials. Here we survey recent key progress in using ILs and PILs in the field of synthetic inorganic chemistry. As well as highlighting the unique features of ILs and PILs that enable advanced synthesis, the effects of adding other solvents to the final products, along with the emerging applications of the created inorganic materials will be discussed. We finally provide an outlook on several development opportunities that could lead to new advancements of this exciting research field. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Research in Chemical Kinetics: Progress Report, January 1, 1978 to September 30, 1978

DOE R&D Accomplishments Database

Rowland, F. S.

1978-01-01

Research was conducted on the following topics: stratospheric chemistry of chlorinated molecules, atmospheric chemistry of methane, atmospheric chemistry of cosmogenic tritium, reactions of energetic and thermal radioactive atoms, methylene chemistry, and laboratory simulation of chemical reactions in Jupiter atmosphere. (DLC)

Development of the Connected Chemistry as Formative Assessment Pedagogy for High School Chemistry Teaching

ERIC Educational Resources Information Center

Park, Mihwa; Liu, Xiufeng; Waight, Noemi

2017-01-01

This paper describes the development of Connected Chemistry as Formative Assessment (CCFA) pedagogy, which integrates three promising teaching and learning approaches, computer models, formative assessments, and learning progressions, to promote student understanding in chemistry. CCFA supports student learning in making connections among the…

Partners for Progress and Prosperity in the Global Chemistry Enterprise

USDA-ARS?s Scientific Manuscript database

In the past several years, there have been many changes facing the global chemistry enterprise. Whereas the overall chemistry enterprise appears to be strong and the chemical industry is still a major contributor to GDP, many chemistry-based products have been commoditized, and chemical employment h...

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Progress in the fields of nuclear chemistry, isolation and chemical properties of synthetic elements, chemical separation of isotopes, radiation chemistry, organic chemistry, chemistry of aquecus systems, electrochemistry of corrosion, nonaqueous systems at high temperature, and chemical physics for the year ending June 20, 1961, is reported. Separate abstracts were prepared for each topic. (M.C.G.)

Mapping the relationship between a learner's belief system and their ability to learn competencies

NASA Astrophysics Data System (ADS)

Matthews, Graeme D.

2009-12-01

This study determines if a relationship exists between the perception that students have towards chemistry and their final grade in the course. A measurement instrument was administered to students enrolled in the first semester of a two semester general chemistry course that measured the perceptions that the students enrolled in the course had towards chemistry. The existence and nature of the relationship between the perceptions held by the students towards chemistry and their final grade in the course were studied. The primary research question determined if there was a relationship between the perceptions that the students have towards chemistry and the final grade they receive in the course. The data indicates that the less chemophobia that the participant had towards chemistry, the higher their final grade in the course and the less difficult the participant perceived chemistry to be as a discipline, the higher their final grade in the course. The secondary research question determines if men and women differ in their perceptions of chemistry. The data indicates that the male participants had a more negative perception of the aptitude, chemophobia, value and gender subscales then the female participants. This means that the male participants had the perception that they had less aptitude and saw less value in the subject matter than the female participants. It also means that because the subscales were all coded to be positively phrased before the final analysis was completed, that the male participants had more chemophobia and believed that gender was more important than the female participants. The tertiary research question determines if there is a relationship between the number of science courses the participants have taken and the perceptions that they have towards chemistry. The data indicates that there was a small negative relationship between the number of science courses taken previously by the participant and the chemophobia subscale. This means that the more science courses the participant has taken, the less chemophobia the participant has towards chemistry and the less they believe that gender plays an important role in being able to achieve a passing grade in a chemistry course.

Chemistry Division: Annual progress report for period ending March 31, 1987

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1987-08-01

This report is divided into the following sections: coal chemistry; aqueous chemistry at high temperatures and pressures; geochemistry of crustal processes to high temperatures and pressures; chemistry of advanced inorganic materials; structure and dynamics of advanced polymeric materials; chemistry of transuranium elements and compounds; separations chemistry; reactions and catalysis in molten salts; surface science related to heterogeneous catalysis; electron spectroscopy; chemistry related to nuclear waste disposal; computational modeling of security document printing; and special topics. (DLC)

Developing Technical Writing Skills in the Physical Chemistry Laboratory: A Progressive Approach Employing Peer Review

ERIC Educational Resources Information Center

Gragson, Derek E.; Hagen, John P.

2010-01-01

Writing formal "journal-style" lab reports is often one of the requirements chemistry and biochemistry students encounter in the physical chemistry laboratory. Helping students improve their technical writing skills is the primary reason this type of writing is a requirement in the physical chemistry laboratory. Developing these skills is an…

Deciphering the physics and chemistry of perovskites with transmission electron microscopy.

PubMed

Polking, Mark J

2016-03-28

Perovskite oxides exhibit rich structural complexity and a broad range of functional properties, including ferroelectricity, ferromagnetism, and superconductivity. The development of aberration correction for the transmission electron microscope and concurrent progress in electron spectroscopy, electron holography, and other techniques has fueled rapid progress in the understanding of the physics and chemistry of these materials. New techniques based on the transmission electron microscope are first surveyed, and the applications of these techniques for the study of the structure, chemistry, electrostatics, and dynamics of perovskite oxides are then explored in detail, with a particular focus on ferroelectric materials.

Final Progress Report, Renewable and Logistics Fuels for Fuel Cells at the Colorado School of Mines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, Neal P.

The objective of this program is to advance the current state of technology of solid-oxide fuel cells (SOFCs) to improve performance when operating on renewable and logistics hydrocarbon fuel streams. Outcomes will include: 1.) new SOFC materials and architectures that address the technical challenges associated with carbon-deposit formation and sulfur poisoning; 2.) new integration strategies for combining fuel reformers with SOFCs; 3.) advanced modeling tools that bridge the scales of fundamental charge-transfer chemistry to system operation and control; and 4.) outreach through creation of the Distinguished Lecturer Series to promote nationwide collaboration with fuel-cell researchers and scientists.

SONEX: NASA SASS Ozone and Nitrogen Oxide Experiment

NASA Technical Reports Server (NTRS)

Newell, Reginald E.; Zhu, Yong; Cho, John; Hu, Yuanlong

1999-01-01

This final report follows closely on our 1998 Annual Progress Report which was forwarded to NASA on November 19, 1998. Rather than reiterate the material therein we note here the continuation of the various items covered. SONEX has proN,Ided a number of opportunities to learn more about the fine-scale structure of the atmosphere. Coupled with the MOZAIC work on layers we can synthesize a new 3-D view of the fine scales that influence atmospheric chemistry. As a side issue we are also relating the features to clear air turbulence which would be, we think, a useful connection for commercial aviation.

Relationships between acid deposition, watershed characteristics, and stream chemistry in Maryland's coastal plain. Final report. Volume 5. Appendix B. 4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, S.; Bartoshesky, J.; Heimbuch, D.

1987-06-01

Contents include: data quality assurance and stream, precipitation, and meteorological data; Granny Finley Branch stream chemistry (routine sampling, storm-event chemistry, longitudinal sampling, groundwater chemistry).

A Markov Model Analysis of Problem-Solving Progress.

ERIC Educational Resources Information Center

Vendlinski, Terry

This study used a computerized simulation and problem-solving tool along with artificial neural networks (ANN) as pattern recognizers to identify the common types of strategies high school and college undergraduate chemistry students would use to solve qualitative chemistry problems. Participants were 134 high school chemistry students who used…

Student Conceptions about Energy Transformations: Progression from General Chemistry to Biochemistry

ERIC Educational Resources Information Center

Wolfson, Adele J.; Rowland, Susan L.; Lawrie, Gwendolyn A.; Wright, Anthony H.

2014-01-01

Students commencing studies in biochemistry must transfer and build on concepts they learned in chemistry and biology classes. It is well established, however, that students have difficulties in transferring critical concepts from general chemistry courses; one key concept is "energy." Most previous work on students' conception of energy…

Carbohydrate CuAAC click chemistry for therapy and diagnosis.

PubMed

He, Xiao-Peng; Zeng, Ya-Li; Zang, Yi; Li, Jia; Field, Robert A; Chen, Guo-Rong

2016-06-24

Carbohydrates are important as signaling molecules and for cellular recognition events, therefore offering scope for the development of carbohydrate-mimetic diagnostics and drug candidates. As a consequence, the construction of carbohydrate-based bioactive compounds and sensors has become an active research area. While the advent of click chemistry has greatly accelerated the progress of medicinal chemistry and chemical biology, recent literature has seen an extensive use of such approaches to construct functionally diverse carbohydrate derivatives. Here we summarize some of the progress, covering the period 2010 to mid-2015, in Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition CuAAC "click chemistry" of carbohydrate derivatives, in the context of potential therapeutic and diagnostic tool development. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

ANALYTICAL CHEMISTRY DIVISION ANNUAL PROGRESS REPORT FOR PERIOD ENDING DECEMBER 31, 1961

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1962-02-01

Research and development progress is reported on analytlcal instrumentation, dlssolver-solution analyses, special research problems, reactor projects analyses, x-ray and spectrochemical analyses, mass spectrometry, optical and electron microscopy, radiochemical analyses, nuclear analyses, inorganic preparations, organic preparations, ionic analyses, infrared spectral studies, anodization of sector coils for the Analog II Cyclotron, quality control, process analyses, and the Thermal Breeder Reactor Projects Analytical Chemistry Laboratory. (M.C.G.)

Impact of General Chemistry on Student Achievement and Progression to Subsequent Chemistry Courses: A Regression Discontinuity Analysis

ERIC Educational Resources Information Center

Shultz, Ginger V.; Gottfried, Amy C.; Winschel, Grace A.

2015-01-01

General chemistry is a gateway course that impacts the STEM trajectory of tens of thousands of students each year, and its role in the introductory curriculum as well as its pedagogical design are the center of an ongoing debate. To investigate the role of general chemistry in the curriculum, we report the results of a posthoc analysis of 10 years…

Molecule by molecule, the physics and chemistry of life: SMB 2007.

PubMed

Block, Steven M; Larson, Matthew H; Greenleaf, William J; Herbert, Kristina M; Guydosh, Nicholas R; Anthony, Peter C

2007-04-01

Interdisciplinary work in the life sciences at the boundaries of biology, chemistry and physics is making enormous strides. This progress was showcased at the recent Single Molecule Biophysics conference.

Molecule by molecule, the physics and chemistry of life: SMB 2007

PubMed Central

Block, Steven M; Larson, Matthew H; Greenleaf, William J; Herbert, Kristina M; Guydosh, Nicholas R; Anthony, Peter C

2007-01-01

Interdisciplinary work in the life sciences at the boundaries of biology, chemistry and physics is making enormous strides. This progress was showcased at the recent Single Molecule Biophysics conference. PMID:17372599

Using Rasch Measurement to Validate an Instrument for Measuring the Quality of Classroom Teaching in Secondary Chemistry Lessons

ERIC Educational Resources Information Center

He, Peng; Liu, Xiufeng; Zheng, Changlong; Jia, Mengying

2016-01-01

This study intends to develop a standardized instrument for measuring classroom teaching and learning in secondary chemistry lessons. Based on previous studies and interviews with expert teachers, the progression of five quality levels was constructed hypothetically to represent the quality of chemistry lessons in Chinese secondary schools. The…

Chemistry Division annual progress report for period ending April 30, 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poutsma, M.L.; Ferris, L.M.; Mesmer, R.E.

1993-08-01

The Chemistry Division conducts basic and applied chemical research on projects important to DOE`s missions in sciences, energy technologies, advanced materials, and waste management/environmental restoration; it also conducts complementary research for other sponsors. The research are arranged according to: coal chemistry, aqueous chemistry at high temperatures and pressures, geochemistry, chemistry of advanced inorganic materials, structure and dynamics of advanced polymeric materials, chemistry of transuranium elements and compounds, chemical and structural principles in solvent extraction, surface science related to heterogeneous catalysis, photolytic transformations of hazardous organics, DNA sequencing and mapping, and special topics.

Alzheimer's disease Braak Stage progressions: reexamined and redefined as Borrelia infection transmission through neural circuits.

PubMed

MacDonald, Alan B

2007-01-01

Brain structure in health is a dynamic energized equation incorporating chemistry, neuronal structure, and circuitry components. The chemistry "piece" is represented by multiple neurotransmitters such as Acetylcholine, Serotonin, and Dopamine. The neuronal structure "piece" incorporates synapses and their connections. And finally circuits of neurons establish "architectural blueprints" of anatomic wiring diagrams of the higher order of brain neuron organizations. In Alzheimer's disease, there are progressive losses in all of these components. Brain structure crumbles. The deterioration in Alzheimer's is ordered, reproducible, and stepwise. Drs. Braak and Braak have described stages in the Alzheimer disease continuum. "Progressions" through Braak Stages benchmark "Regressions" in Cognitive function. Under the microscope, the Stages of Braak commence in brain regions near to the hippocampus, and over time, like a tsunami wave of destruction, overturn healthy brain regions, with neurofibrillary tangle damaged neurons "marching" through the temporal lobe, neocortex and occipital cortex. In effect the destruction ascends from the limbic regions to progressively destroy the higher brain centers. Rabies infection also "begins low and finishes high" in its wave of destruction of brain tissue. Herpes Zoster infections offer the paradigm of clinical latency of infection inside of nerves before the "marching commences". Varicella Zoster virus enters neurons in the pediatric years. Dormant virus remains inside the neurons for 50-80 years, tissue damage late in life (shingles) demonstrates the "march of the infection" down neural pathways (dermatomes) as linear areas of painful blisters loaded with virus from a childhood infection. Amalgamation of Zoster with Rabies models produces a hybrid model to explain all of the Braak Stages of Alzheimer's disease under a new paradigm, namely "Alzheimer's neuroborreliosis" in which latent Borrelia infections ascend neural circuits through the hippocampus to the higher brain centers, creating a trail of neurofibrillary tangle injured neurons in neural circuits of cholinergic neurons by transsynaptic transmission of infection from nerve to nerve.

Exploring hypothetical learning progressions for the chemistry of nitrogen and nuclear processes

NASA Astrophysics Data System (ADS)

Henry, Deborah McKern

Chemistry is a bridge that connects a number of scientific disciplines. High school students should be able to determine whether scientific information is accurate, how chemistry applies to daily life, and the mechanism by which systems operate (NRC, 2012). This research focuses on describing hypothetical learning progressions for student understanding of the chemical reactions of nitrogen and nuclear processes and examines whether there is consistency in scientific reasoning between these two distinct conceptual areas. The constant comparative method was used to analyze the written products of students including homework, formative and summative tests, laboratory notebooks, reflective journals, written presentations, and discussion board contributions via Edmodo (an online program). The ten participants were 15 and 16 year old students enrolled in a general high school chemistry course. Instruction took place over a ten week period. The learning progression levels ranged from 0 to 4 and were described as missing, novice, intermediate, proficient, and expert. The results were compared to the standards set by the NRC with a lower anchor (expectations for grade 8) and upper anchor (expectations for grade 12). The results indicate that, on average, students were able to reach an intermediate level of understanding for these concepts.

An Introduction to the Fundamentals of Chemistry for the Marine Engineer.

ERIC Educational Resources Information Center

Schlenker, Richard M.

This document describes an introduction course in the fundamentals of chemistry for marine engineers. The course is modularized, audio tutorial allowing the student to progress at his own rate while integrating laboratory and lecture materials. (SL)

Principles of Chemical Bonding and Band Gap Engineering in Hybrid Organic-Inorganic Halide Perovskites.

PubMed

Walsh, Aron

2015-03-19

The performance of solar cells based on hybrid halide perovskites has seen an unparalleled rate of progress, while our understanding of the underlying physical chemistry of these materials trails behind. Superficially, CH 3 NH 3 PbI 3 is similar to other thin-film photovoltaic materials: a semiconductor with an optical band gap in the optimal region of the electromagnetic spectrum. Microscopically, the material is more unconventional. Progress in our understanding of the local and long-range chemical bonding of hybrid perovskites is discussed here, drawing from a series of computational studies involving electronic structure, molecular dynamics, and Monte Carlo simulation techniques. The orientational freedom of the dipolar methylammonium ion gives rise to temperature-dependent dielectric screening and the possibility for the formation of polar (ferroelectric) domains. The ability to independently substitute on the A, B, and X lattice sites provides the means to tune the optoelectronic properties. Finally, ten critical challenges and opportunities for physical chemists are highlighted.

Near-Field Scanning Optical Microscopy of Soft, Biological, or Rough Objects in Aqueous Environment: Challenges and some Remedies to Circumvent

NASA Technical Reports Server (NTRS)

Vikram, C. S.; Witherow, W. K.

1999-01-01

Near-field scanning optical microscopy is an established technique for sub-wavelength spatial resolution in imaging, spectroscopy, material science, surface chemistry, polarimetry, etc. A significant amount of confidence has been established for thin hard specimens in air. However when soft, biological, rough, in aqueous environment object, or a combination is involved, the progress has been slow. The tip-sample mechanical interaction, heat effects to sample, drag effects to the probe, difficulty in controlling tip-sample separation in case of rough objects, light scattering from sample thickness, etc. create problems. Although these problems are not even fully understood, there have been attempts to study them with the aim of performing reliable operations. In this review we describe these attempts. Starting with general problems encountered, various effects like polarization, thermal, and media are covered. The roles of independent tip-sample distance control tools in the relevant situations are then described. Finally progress in fluid cell aspect has been summarized.

Principles of Chemical Bonding and Band Gap Engineering in Hybrid Organic–Inorganic Halide Perovskites

PubMed Central

2015-01-01

The performance of solar cells based on hybrid halide perovskites has seen an unparalleled rate of progress, while our understanding of the underlying physical chemistry of these materials trails behind. Superficially, CH3NH3PbI3 is similar to other thin-film photovoltaic materials: a semiconductor with an optical band gap in the optimal region of the electromagnetic spectrum. Microscopically, the material is more unconventional. Progress in our understanding of the local and long-range chemical bonding of hybrid perovskites is discussed here, drawing from a series of computational studies involving electronic structure, molecular dynamics, and Monte Carlo simulation techniques. The orientational freedom of the dipolar methylammonium ion gives rise to temperature-dependent dielectric screening and the possibility for the formation of polar (ferroelectric) domains. The ability to independently substitute on the A, B, and X lattice sites provides the means to tune the optoelectronic properties. Finally, ten critical challenges and opportunities for physical chemists are highlighted. PMID:25838846

Spectroscopic and computational investigation of actinium coordination chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferrier, Maryline Ghislaine; Batista, Enrique Ricardo; Berg, John M.

Actinium-225 is a promising isotope for targeted-α therapy. Unfortunately, progress in developing chelators for medicinal applications has been hindered by a limited understanding of actinium chemistry. This knowledge gap is primarily associated with handling actinium, as it is highly radioactive and in short supply. Hence, Ac III reactivity is often inferred from the lanthanides and minor actinides (that is, Am, Cm), with limited success. Here we overcome these challenges and characterize actinium in HCl solutions using X-ray absorption spectroscopy and molecular dynamics density functional theory. The Ac–Cl and Ac–O H2O distances are measured to be 2.95(3) and 2.59(3) Å, respectively.more » The X-ray absorption spectroscopy comparisons between Ac III and Am III in HCl solutions indicate Ac III coordinates more inner-sphere Cl 1– ligands (3.2±1.1) than Am III (0.8±0.3). Finally, these results imply diverse reactivity for the +3 actinides and highlight the unexpected and unique Ac III chemical behaviour.« less

Spectroscopic and computational investigation of actinium coordination chemistry

DOE PAGES

Ferrier, Maryline Ghislaine; Batista, Enrique Ricardo; Berg, John M.; ...

2016-08-17

Actinium-225 is a promising isotope for targeted-α therapy. Unfortunately, progress in developing chelators for medicinal applications has been hindered by a limited understanding of actinium chemistry. This knowledge gap is primarily associated with handling actinium, as it is highly radioactive and in short supply. Hence, Ac III reactivity is often inferred from the lanthanides and minor actinides (that is, Am, Cm), with limited success. Here we overcome these challenges and characterize actinium in HCl solutions using X-ray absorption spectroscopy and molecular dynamics density functional theory. The Ac–Cl and Ac–O H2O distances are measured to be 2.95(3) and 2.59(3) Å, respectively.more » The X-ray absorption spectroscopy comparisons between Ac III and Am III in HCl solutions indicate Ac III coordinates more inner-sphere Cl 1– ligands (3.2±1.1) than Am III (0.8±0.3). Finally, these results imply diverse reactivity for the +3 actinides and highlight the unexpected and unique Ac III chemical behaviour.« less

Dopamine: Just the Right Medicine for Membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Hao-Cheng; Waldman, Ruben Z.; Wu, Ming-Bang

Mussel-inspired chemistry has attracted widespread interest in membrane science and technology. Demonstrating the rapid growth of this field over the past several years, substantial progress has been achieved in both mussel-inspired chemistry and membrane surface engineering based on mussel-inspired coatings. At this stage, it is valuable to summarize the most recent and distinctive developments, as well as to frame the challenges and opportunities remaining in this field. In this review, recent advances in rapid and controllable deposition of mussel-inspired coatings, dopamine-assisted codeposition technology, and photoinitiated grafting directly on mussel-inspired coatings are presented. Some of these technologies have not yet beenmore » employed directly in membrane science. Beyond discussing advances in conventional membrane processes, emerging applications of mussel-inspired coatings in membranes are discussed, including as a skin layer in nanofiltration, interlayer in metal-organic framework based membranes, hydrophilic layer in Janus membranes, and protective layer in catalytic membranes. Finally, some critical unsolved challenges are raised in this field and some potential pathways are proposed to address them.« less

Dopamine: Just the Right Medicine for Membranes

DOE PAGES

Yang, Hao-Cheng; Waldman, Ruben Z.; Wu, Ming-Bang; ...

2018-01-09

Mussel-inspired chemistry has attracted widespread interest in membrane science and technology. Demonstrating the rapid growth of this field over the past several years, substantial progress has been achieved in both mussel-inspired chemistry and membrane surface engineering based on mussel-inspired coatings. At this stage, it is valuable to summarize the most recent and distinctive developments, as well as to frame the challenges and opportunities remaining in this field. In this review, recent advances in rapid and controllable deposition of mussel-inspired coatings, dopamine-assisted codeposition technology, and photoinitiated grafting directly on mussel-inspired coatings are presented. Some of these technologies have not yet beenmore » employed directly in membrane science. Beyond discussing advances in conventional membrane processes, emerging applications of mussel-inspired coatings in membranes are discussed, including as a skin layer in nanofiltration, interlayer in metal-organic framework based membranes, hydrophilic layer in Janus membranes, and protective layer in catalytic membranes. Finally, some critical unsolved challenges are raised in this field and some potential pathways are proposed to address them.« less

Final-Year Education Projects for Undergraduate Chemistry Students

ERIC Educational Resources Information Center

Page, Elizabeth

2011-01-01

The Undergraduate Ambassadors Scheme provides an opportunity for students in their final year of the chemistry degree course at the University of Reading to choose an educational project as an alternative to practical research. The undergraduates work in schools where they can be regarded as role models and offer one way of inspiring pupils to…

Effect of Food, Diet and Nutrition on Military Readiness and Preparedness of Army Personnel and Dependents in a Peacetime Environment

DTIC Science & Technology

1991-08-15

Beckman Synchron CX5 automated clinical chemistry system; b. Coulter STKS automated hematology system with five part differential; c. Perkin Elmer P1000...500,000 of Pennington center funds were used to equip this laboratory. Progress on Method Development a. General Chemistry Most routine chemistry analyses...are performed on the Beckman Synchron CX5 automated chemistry system. A description of this system is given in the Second Annual Report, pg 8 (1

Mathematical challenges from theoretical/computational chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-12-31

The committee believes that this report has relevance and potentially valuable suggestions for a wide range of readers. Target audiences include: graduate departments in the mathematical and chemical sciences; federal and private agencies that fund research in the mathematical and chemical sciences; selected industrial and government research and development laboratories; developers of software and hardware for computational chemistry; and selected individual researchers. Chapter 2 of this report covers some history of computational chemistry for the nonspecialist, while Chapter 3 illustrates the fruits of some past successful cross-fertilization between mathematical scientists and computational/theoretical chemists. In Chapter 4 the committee has assembledmore » a representative, but not exhaustive, survey of research opportunities. Most of these are descriptions of important open problems in computational/theoretical chemistry that could gain much from the efforts of innovative mathematical scientists, written so as to be accessible introductions to the nonspecialist. Chapter 5 is an assessment, necessarily subjective, of cultural differences that must be overcome if collaborative work is to be encouraged between the mathematical and the chemical communities. Finally, the report ends with a brief list of conclusions and recommendations that, if followed, could promote accelerated progress at this interface. Recognizing that bothersome language issues can inhibit prospects for collaborative research at the interface between distinctive disciplines, the committee has attempted throughout to maintain an accessible style, in part by using illustrative boxes, and has included at the end of the report a glossary of technical terms that may be familiar to only a subset of the target audiences listed above.« less

Materials and Molecular Research Division annual report 1983

DOE Office of Scientific and Technical Information (OSTI.GOV)

Searcy, A.W.; Muller, R.H.; Peterson, C.V.

1984-07-01

Progress is reported in the following fields: materials sciences (metallurgy and ceramics, solid-state physics, materials chemistry), chemical sciences (fundamental interactions, processes and techniques), actinide chemistry, fossil energy, electrochemical energy storage systems, superconducting magnets, semiconductor materials and devices, and work for others. (DLC)

Ultrafast studies of shock induced chemistry-scaling down the size by turning up the heat

NASA Astrophysics Data System (ADS)

McGrane, Shawn

2015-06-01

We will discuss recent progress in measuring time dependent shock induced chemistry on picosecond time scales. Data on the shock induced chemistry of liquids observed through picosecond interferometric and spectroscopic measurements will be reconciled with shock induced chemistry observed on orders of magnitude larger time and length scales from plate impact experiments reported in the literature. While some materials exhibit chemistry consistent with simple thermal models, other materials, like nitromethane, seem to have more complex behavior. More detailed measurements of chemistry and temperature across a broad range of shock conditions, and therefore time and length scales, will be needed to achieve a real understanding of shock induced chemistry, and we will discuss efforts and opportunities in this direction.

Plasma chemistry as a tool for green chemistry, environmental analysis and waste management.

PubMed

Mollah, M Y; Schennach, R; Patscheider, J; Promreuk, S; Cocke, D L

2000-12-15

The applications of plasma chemistry to environmental problems and to green chemistry are emerging fields that offer unique opportunities for advancement. There has been substantial progress in the application of plasmas to analytical diagnostics and to waste reduction and waste management. This review discusses the chemistry and physics necessary to a basic understanding of plasmas, something that has been missing from recent technical reviews. The current status of plasmas in environmental chemistry is summarized and emerging areas of application for plasmas are delineated. Plasmas are defined and discussed in terms of their properties that make them useful for environmental chemistry. Information is drawn from diverse fields to illustrate the potential applications of plasmas in analysis, materials modifications and hazardous waste treatments.

Conceptual Versus Algorithmic Problem-solving: Focusing on Problems Dealing with Conservation of Matter in Chemistry

NASA Astrophysics Data System (ADS)

Salta, Katerina; Tzougraki, Chryssa

2011-08-01

The students' performance in various types of problems dealing with the conservation of matter during chemical reactions has been investigated at different levels of schooling. The participants were 499 ninth grade (ages 14, 15 years) and 624 eleventh grade (ages 16, 17 years) Greek students. Data was collected using a written questionnaire concerning basic chemical concepts. Results of statistical factor and correlation analysis confirmed the classification of the problems used in three types: "algorithmic-type", "particulate-type", and "conceptual-type". All the students had a far better performance in "particulate-type" problems than in the others. Although students' ability in solving "algorithmic-type" problem increases as their school experience in chemistry progresses, their ability in solving "conceptual-type" problems decreases. Students' achievement in chemistry was measured by a Chemical Concepts Test (CCT) containing 57 questions of various forms. High-achievement students scored higher both on "algorithmic-type" and "particulate-type" problems than low achievers with the greatest difference observed in solving "algorithmic-type" problems. It is concluded that competence in "particulate-type" and "algorithmic-type" problem solving may be independent of competence in solving "conceptual-type" ones. Furthermore, it was found that students' misconceptions concerning chemical reactions and equivalence between mass and energy are impediments to their problem solving abilities. Finally, based on the findings, few suggestions concerning teaching practices are discussed.

Students' perception of an integrated approach of teaching entire sequence of medicinal chemistry, pharmacology, and pharmacotherapeutics courses in PharmD curriculum.

PubMed

Islam, Mohammed A; Schweiger, Teresa A

2015-04-01

To develop an integrated approach of teaching medicinal chemistry, pharmacology, and pharmacotherapeutics and to evaluate students' perceptions of integration as they progress through the PharmD curriculum. Instructors from each discipline jointly mapped the course contents and sequenced the course delivery based on organ systems/disease states. Medicinal chemistry and pharmacology contents were integrated and aligned with respective pharmacotherapeutics contents to deliver throughout second and third year of the curriculum. In addition to classroom lectures, active learning strategies such as recitation, case studies, online-discussion boards, open book quizzes, and writing patient progress notes were incorporated to enhance student learning. Student learning was assessed by examination scores, patient progress notes, and writing assignments. The impact of course integration was evaluated by a Web-based survey. One hundred and sixty-nine students completed the survey. Students exhibited positive attitude toward the integrated approach of teaching medicinal chemistry, pharmacology, and therapeutics. The P3 and P4 students better appreciated the benefits of integration compared to P2 students (P < .05). Students perceived the course integration as an effective way of learning. This study supports course improvement and the viability of expanding the concept of integration to other courses in the curriculum. © The Author(s) 2014.

Research advances in polymer emulsion based on "core-shell" structure particle design.

PubMed

Ma, Jian-zhong; Liu, Yi-hong; Bao, Yan; Liu, Jun-li; Zhang, Jing

2013-09-01

In recent years, quite many studies on polymer emulsions with unique core-shell structure have emerged at the frontier between material chemistry and many other fields because of their singular morphology, properties and wide range of potential applications. Organic substance as a coating material onto either inorganic or organic internal core materials promises an unparalleled opportunity for enhancement of final functions through rational designs. This contribution provides a brief overview of recent progress in the synthesis, characterization, and applications of both inorganic-organic and organic-organic polymer emulsions with core-shell structure. In addition, future research trends in polymer composites with core-shell structure are also discussed in this review. Copyright © 2013 Elsevier B.V. All rights reserved.

Promoting Student Development of Models and Scientific Inquiry Skills in Acid-Base Chemistry: An Important Skill Development in Preparation for AP Chemistry

ERIC Educational Resources Information Center

Hale-Hanes, Cara

2015-01-01

In this study, two groups of 11th grade chemistry students (n = 210) performed a sequence of hands-on and virtual laboratories that were progressively more inquiry-based. One-half of the students did the laboratory sequence with the addition of a teacher-led discussion connecting student data to student-generated visual representations of…

Chemistry of Bimetallic Linked Cyclopentadienyl Complexes: Progress Report, 1 December 1986 --30 November 1989

DOE R&D Accomplishments Database

Schrock, R. R.

1989-01-01

Research continued on the chemistry and preparation of bimetallic cyclopentadienyl complexes containing up to two tungsten or one tungsten and a cobalt, rhodium, or ruthenium. The general method for preparation and analysis of polyenes is also discussed. (CBS)

Synchrotron X-ray Analytical Techniques for Studying Materials Electrochemistry in Rechargeable Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Feng; Liu, Yijin; Yu, Xiqian

Rechargeable battery technologies have ignited major breakthroughs in contemporary society, including but not limited to revolutions in transportation, electronics, and grid energy storage. The remarkable development of rechargeable batteries is largely attributed to in-depth efforts to improve battery electrode and electrolyte materials. There are, however, still intimidating challenges of lower cost, longer cycle and calendar life, higher energy density, and better safety for large scale energy storage and vehicular applications. Further progress with rechargeable batteries may require new chemistries (lithium ion batteries and beyond) and better understanding of materials electrochemistry in the various battery technologies. In the past decade, advancementmore » of battery materials has been complemented by new analytical techniques that are capable of probing battery chemistries at various length and time scales. Synchrotron X-ray techniques stand out as one of the most effective methods that allows for nearly nondestructive probing of materials characteristics such as electronic and geometric structures with various depth sensitivities through spectroscopy, scattering, and imaging capabilities. This article begins with the discussion of various rechargeable batteries and associated important scientific questions in the field, followed by a review of synchrotron X-ray based analytical tools (scattering, spectroscopy and imaging) and their successful applications (ex situ, in situ, and in operando) in gaining fundamental insights into these scientific questions. Furthermore, electron microscopy and spectroscopy complement the detection length scales of synchrotron X-ray tools, and are also discussed towards the end. We highlight the importance of studying battery materials by combining analytical techniques with complementary length sensitivities, such as the combination of X-ray absorption spectroscopy and electron spectroscopy with spatial resolution, because a sole technique may lead to biased and inaccurate conclusions. We then discuss the current progress of experimental design for synchrotron experiments and methods to mitigate beam effects. Finally, a perspective is provided to elaborate how synchrotron techniques can impact the development of next-generation battery chemistries.« less

Synchrotron X-ray Analytical Techniques for Studying Materials Electrochemistry in Rechargeable Batteries

DOE PAGES

Lin, Feng; Liu, Yijin; Yu, Xiqian; ...

2017-08-30

Rechargeable battery technologies have ignited major breakthroughs in contemporary society, including but not limited to revolutions in transportation, electronics, and grid energy storage. The remarkable development of rechargeable batteries is largely attributed to in-depth efforts to improve battery electrode and electrolyte materials. There are, however, still intimidating challenges of lower cost, longer cycle and calendar life, higher energy density, and better safety for large scale energy storage and vehicular applications. Further progress with rechargeable batteries may require new chemistries (lithium ion batteries and beyond) and better understanding of materials electrochemistry in the various battery technologies. In the past decade, advancementmore » of battery materials has been complemented by new analytical techniques that are capable of probing battery chemistries at various length and time scales. Synchrotron X-ray techniques stand out as one of the most effective methods that allows for nearly nondestructive probing of materials characteristics such as electronic and geometric structures with various depth sensitivities through spectroscopy, scattering, and imaging capabilities. This article begins with the discussion of various rechargeable batteries and associated important scientific questions in the field, followed by a review of synchrotron X-ray based analytical tools (scattering, spectroscopy and imaging) and their successful applications (ex situ, in situ, and in operando) in gaining fundamental insights into these scientific questions. Furthermore, electron microscopy and spectroscopy complement the detection length scales of synchrotron X-ray tools, and are also discussed towards the end. We highlight the importance of studying battery materials by combining analytical techniques with complementary length sensitivities, such as the combination of X-ray absorption spectroscopy and electron spectroscopy with spatial resolution, because a sole technique may lead to biased and inaccurate conclusions. We then discuss the current progress of experimental design for synchrotron experiments and methods to mitigate beam effects. Finally, a perspective is provided to elaborate how synchrotron techniques can impact the development of next-generation battery chemistries.« less

Arguments, contradictions, resistances, and conceptual change in students' understanding of atomic structure

NASA Astrophysics Data System (ADS)

Niaz, Mansoor; Aguilera, Damarys; Maza, Arelys; Liendo, Gustavo

2002-07-01

Most general chemistry courses and textbooks emphasize experimental details and lack a history and philosophy of science perspective. The objective of this study is to facilitate freshman general chemistry students' understanding of atomic structure based on the work of Thomson, Rutherford, and Bohr. It is hypothesized that classroom discussions based on arguments/counterarguments of the heuristic principles, on which these scientists based their atomic models, can facilitate students' conceptual understanding. This study is based on 160 freshman students enrolled in six sections of General Chemistry I (three sections formed part of the experimental group). All three models (Thomson, Rutherford, and Bohr) were presented to the experimental and control group students in the traditional manner, as found in most textbooks. After this, the three sections of the experimental group participated in the discussion of six items with alternative responses. Students were first asked to select a response and then participate in classroom discussions leading to arguments in favor or against the selected response and finally select a new response. Three weeks after having discussed the six items, both the experimental and control groups presented a monthly exam (based on the three models) and after another 3 weeks a semester exam. Results obtained show that given the opportunity to argue and discuss, students' understanding can go beyond the simple regurgitation of experimental details. Performance of the experimental group showed contradictions, resistances, and progressive conceptual change with considerable and consistent improvement in the last item. It is concluded that if we want our students to understand scientific progress and practice, then it is important that we include the experimental details not as a rhetoric of conclusions (Schwab, 1962, The teaching of science as enquiry, Cambridge, MA, Harward University Press; Schwab, 1974, Conflicting conceptions of curriculum, Berkeley, CA, McCutchan) but as heuristic principles (Lakatos, 1970, Criticism and the growth of knowledge, Cambridge, UK, Cambridge University Press, pp. 91-195), which were based on arguments, controversies, and interpretations of the scientists.

Let's Face(book) It: Analyzing Interactions in Social Network Groups for Chemistry Learning

ERIC Educational Resources Information Center

Rap, Shelley; Blonder, Ron

2016-01-01

We examined how social network (SN) groups contribute to the learning of chemistry. The main goal was to determine whether chemistry learning could occur in the group discourse. The emphasis was on groups of students in the 11th and 12th grades who learn chemistry in preparation for their final external examination. A total of 1118 discourse…

Benefits of Using a Problem-Solving Scaffold for Teaching and Learning Synthesis in Undergraduate Organic Chemistry I

ERIC Educational Resources Information Center

Sloop, Joseph C.; Tsoi, Mai Yin; Coppock, Patrick

2016-01-01

A problem-solving scaffold approach to synthesis was developed and implemented in two intervention sections of Chemistry 2211K (Organic Chemistry I) at Georgia Gwinnett College (GGC). A third section of Chemistry 2211K at GGC served as the control group for the experiment. Synthesis problems for chapter quizzes and the final examination were…

Monthly Progress Report No. 60 for April 1948

DOE Office of Scientific and Technical Information (OSTI.GOV)

Various

This report gives a short summary of each of the following programs: (1) 184-inch Cyclotron Program; (2) 60-inch Cyclotron Program; (3) Synchrotron Program; (4) Linear Accelerator Program; (5) Experimental Physics; (6) Theoretical Physics; (7) Chemistry; (8) Medical Physics; and (9) Health Physics and Chemistry.

Clinical chemistry through Clinical Chemistry: a journal timeline.

PubMed

Rej, Robert

2004-12-01

The establishment of the modern discipline of clinical chemistry was concurrent with the foundation of the journal Clinical Chemistry and that of the American Association for Clinical Chemistry in the late 1940s and early 1950s. To mark the 50th volume of this Journal, I chronicle and highlight scientific milestones, and those within the discipline, as documented in the pages of Clinical Chemistry. Amazing progress has been made in the field of laboratory diagnostics over these five decades, in many cases paralleling-as well as being bolstered by-the rapid pace in the development of computer technologies. Specific areas of laboratory medicine particularly well represented in Clinical Chemistry include lipids, endocrinology, protein markers, quality of laboratory measurements, molecular diagnostics, and general advances in methodology and instrumentation.

Recent advances in H-phosphonate chemistry. Part 1. H-phosphonate esters: synthesis and basic reactions.

PubMed

Sobkowski, Michal; Kraszewski, Adam; Stawinski, Jacek

2015-01-01

This review covers recent progress in the preparation of H-phosphonate mono- and diesters, basic studies on mechanistic and stereochemical aspects of this class of phosphorus compounds, and their fundamental chemistry in terms of transformation of P-H bonds into P-heteroatom bonds. Selected recent applications of H-phosphonate derivatives in basic organic phosphorus chemistry and in the synthesis of biologically important phosphorus compounds are also discussed.

Experimental and Theoretical Studies of Atmosphereic Inorganic Chlorine Chemistry

NASA Technical Reports Server (NTRS)

Sander, Stanley P.; Friedl, Randall R.

1993-01-01

Over the last five years substantial progress has been made in defining the realm of new chlorine chemistry in the polar stratosphere. Application of existing experimental techniques to potentially important chlorine-containing compounds has yielded quantitative kinetic and spectroscopic data as well as qualitative mechanistic insights into the relevant reactions.

Rethinking Chemistry: A Learning Progression on Chemical Thinking

ERIC Educational Resources Information Center

Sevian, Hannah; Talanquer, Vicente

2014-01-01

Dominant educational approaches in chemistry focus on the learning of somewhat isolated concepts and ideas about chemical substances and reactions. Reform efforts often seek to engage students in the generation of knowledge through the investigation of chemical phenomena, with emphasis on the development and application of models to build causal…

Student Engagement with a Science Simulation: Aspects That Matter

ERIC Educational Resources Information Center

Rodrigues, Susan; Gvozdenko, Eugene

2011-01-01

It is argued that multimedia technology affords an opportunity to better visualise complex relationships often seen in chemistry. This paper describes the influence of chemistry simulation design facets on user progress through a simulation. Three versions of an acid-base titration simulation were randomly allocated to 36 volunteers to examine…

USSR Report, Chemistry

DTIC Science & Technology

1984-01-06

Sep-Oct 83) ................................. ANALYTICAL CHEMISTRY Ionometric Determination of Copper in Organic Compounds S(S. L. Davydova, et al...Committee Reviews Progress in Fertilizer Industry (EKONOMICHESKAYA GAZETA, No 42, Oct 83) .................. 30 INORGANIC COMPOUNDS Speed of Ultrasound...Sep 83).. ........... .......... . . .. . . . . .... 39 NITROGEN COMPOUNDS Phototropy of Quaternary Ammonium Salts of N,N’-Bis- Substituted Diimides

Putting the Laboratory at the Center of Teaching Chemistry

ERIC Educational Resources Information Center

Bopegedera, A. M. R. P.

2011-01-01

This article describes an effective approach to teaching chemistry by bringing the laboratory to the center of teaching, to bring the excitement of discovery to the learning process. The lectures and laboratories are closely integrated to provide a holistic learning experience. The laboratories progress from verification to open-inquiry and…

Supramolecular chemistry at interfaces: host-guest interactions for fabricating multifunctional biointerfaces.

PubMed

Yang, Hui; Yuan, Bin; Zhang, Xi; Scherman, Oren A

2014-07-15

CONSPECTUS: Host-guest chemistry can greatly improve the selectivity of biomolecule-ligand binding on account of recognition-directed interactions. In addition, functional structures and the actuation of supramolecular assemblies in molecular systems can be controlled efficiently through various host-guest chemistry. Together, these highly selective, strong yet dynamic interactions can be exploited as an alternative methodology for applications in the field of programmable and controllable engineering of supramolecular soft materials through the reversible binding between complementary components. Many processes in living systems such as biotransformation, transportation of matter, and energy transduction begin with interfacial molecular recognition, which is greatly influenced by various external stimuli at biointerfaces. Detailed investigations about the molecular recognition at interfaces can result in a better understanding of life science, and further guide us in developing new biomaterials and medicines. In order to mimic complicated molecular-recognition systems observed in nature that adapt to changes in their environment, combining host-guest chemistry and surface science is critical for fabricating the next generation of multifunctional biointerfaces with efficient stimuli-responsiveness and good biocompatibility. In this Account, we will summarize some recent progress on multifunctional stimuli-responsive biointerfaces and biosurfaces fabricated by cyclodextrin- or cucurbituril-based host-guest chemistry and highlight their potential applications including drug delivery, bioelectrocatalysis, and reversible adsorption and resistance of peptides, proteins, and cells. In addition, these biointerfaces and biosurfaces demonstrate efficient response toward various external stimuli, such as UV light, pH, redox chemistry, and competitive guests. All of these external stimuli can aid in mimicking the biological stimuli evident in complex biological environments. We begin by reviewing the current state of stimuli-responsive supramolecular assemblies formed by host-guest interactions, discussing how to transfer host-guest chemistry from solution onto surfaces required for fabricating multifunctional biosurfaces and biointerfaces. Then, we present different stimuli-responsive biosurfaces and biointerfaces, which have been prepared through a combination of cyclodextrin- or cucurbituril-based host-guest chemistry and various surface technologies such as self-assembled monolayers or layer-by-layer assembly. Moreover, we discuss the applications of these biointerfaces and biosurfaces in the fields of drug release, reversible adsorption and release of some organic molecules, peptides, proteins, and cells, and photoswitchable bioelectrocatalysis. In addition, we summarize the merits and current limitations of these methods for fabricating multifunctional stimuli-responsive biointerfaces in a dynamic noncovalent manner. Finally, we present possible strategies for future designs of stimuli-responsive multifunctional biointerfaces and biosurfaces by combining host-guest chemistry with surface science, which will lead to further critical development of supramolecular chemistry at interfaces.

The Emergence of a Learning Progression in Middle School Chemistry

ERIC Educational Resources Information Center

Johnson, Philip; Tymms, Peter

2011-01-01

Previously, a small scale, interview-based, 3-year longitudinal study (ages 11-14) in one school had suggested a learning progression related to the concept of a substance. This article presents the results of a large-scale, cross-sectional study which used Rasch modeling to test the hypothesis of the learning progression. Data were collected from…

Teaching Chemistry with Electron Density Models

NASA Astrophysics Data System (ADS)

Shusterman, Gwendolyn P.; Shusterman, Alan J.

1997-07-01

Linus Pauling once said that a topic must satisfy two criteria before it can be taught to students. First, students must be able to assimilate the topic within a reasonable amount of time. Second, the topic must be relevant to the educational needs and interests of the students. Unfortunately, the standard general chemistry textbook presentation of "electronic structure theory", set as it is in the language of molecular orbitals, has a difficult time satisfying either criterion. Many of the quantum mechanical aspects of molecular orbitals are too difficult for most beginning students to appreciate, much less master, and the few applications that are presented in the typical textbook are too limited in scope to excite much student interest. This article describes a powerful new method for teaching students about electronic structure and its relevance to chemical phenomena. This method, which we have developed and used for several years in general chemistry (G.P.S.) and organic chemistry (A.J.S.) courses, relies on computer-generated three-dimensional models of electron density distributions, and largely satisfies Pauling's two criteria. Students find electron density models easy to understand and use, and because these models are easily applied to a broad range of topics, they successfully convey to students the importance of electronic structure. In addition, when students finally learn about orbital concepts they are better prepared because they already have a well-developed three-dimensional picture of electronic structure to fall back on. We note in this regard that the types of models we use have found widespread, rigorous application in chemical research (1, 2), so students who understand and use electron density models do not need to "unlearn" anything before progressing to more advanced theories.

Alkane Oxidation: Methane Monooxygenases, Related Enzymes, and Their Biomimetics.

PubMed

Wang, Vincent C-C; Maji, Suman; Chen, Peter P-Y; Lee, Hung Kay; Yu, Steve S-F; Chan, Sunney I

2017-07-12

Methane monooxygenases (MMOs) mediate the facile conversion of methane into methanol in methanotrophic bacteria with high efficiency under ambient conditions. Because the selective oxidation of methane is extremely challenging, there is considerable interest in understanding how these enzymes carry out this difficult chemistry. The impetus of these efforts is to learn from the microbes to develop a biomimetic catalyst to accomplish the same chemical transformation. Here, we review the progress made over the past two to three decades toward delineating the structures and functions of the catalytic sites in two MMOs: soluble methane monooxygenase (sMMO) and particulate methane monooxygenase (pMMO). sMMO is a water-soluble three-component protein complex consisting of a hydroxylase with a nonheme diiron catalytic site; pMMO is a membrane-bound metalloenzyme with a unique tricopper cluster as the site of hydroxylation. The metal cluster in each of these MMOs harnesses O 2 to functionalize the C-H bond using different chemistry. We highlight some of the common basic principles that they share. Finally, the development of functional models of the catalytic sites of MMOs is described. These efforts have culminated in the first successful biomimetic catalyst capable of efficient methane oxidation without overoxidation at room temperature.

Thermodynamics and Mechanics of Membrane Curvature Generation and Sensing by Proteins and Lipids

PubMed Central

Baumgart, Tobias; Capraro, Benjamin R.; Zhu, Chen; Das, Sovan L.

2014-01-01

Research investigating lipid membrane curvature generation and sensing is a rapidly developing frontier in membrane physical chemistry and biophysics. The fast recent progress is based on the discovery of a plethora of proteins involved in coupling membrane shape to cellular membrane function, the design of new quantitative experimental techniques to study aspects of membrane curvature, and the development of analytical theories and simulation techniques that allow a mechanistic interpretation of quantitative measurements. The present review first provides an overview of important classes of membrane proteins for which function is coupled to membrane curvature. We then survey several mechanisms that are assumed to underlie membrane curvature sensing and generation. Finally, we discuss relatively simple thermodynamic/mechanical models that allow quantitative interpretation of experimental observations. PMID:21219150

The Problem of Extraterrestrial Civilizations and Extrasolar Planets

NASA Astrophysics Data System (ADS)

Mickaelian, A. M.

2015-07-01

The problem of extraterrestrial intelligence is the best example of multidisciplinary science. Here philosophy and religion, astronomy, radiophysics, spectrography, space flights and astronautics, geology and planetology, astroecology, chemistry and biology, history and archaeology, psychology, sociology, linguistics, diplomacy, UFOs and peculiar phenomena are involved. Among these many-sided studies, astronomers have probably displayed the most progress by discovering thousands of extrasolar planets. At present, a number of search programs are being accomplished, including those with space telescopes, and planets in so-called "habitable zone" are considered as most important ones, for which various orbital and physical parameters are being calculated. As the discovery of extraterrestrial life is the final goal, a special attention is given to Earth-like planets, for the discovery of which most sensitive technical means are necessary.

Polysaccharide‐Based Controlled Release Systems for Therapeutics Delivery and Tissue Engineering: From Bench to Bedside

PubMed Central

Miao, Tianxin; Wang, Junqing; Zeng, Yun; Chen, Xiaoyuan

2018-01-01

Abstract Polysaccharides or polymeric carbohydrate molecules are long chains of monosaccharides that are linked by glycosidic bonds. The naturally based structural materials are widely applied in biomedical applications. This article covers four different types of polysaccharides (i.e., alginate, chitosan, hyaluronic acid, and dextran) and emphasizes their chemical modification, preparation approaches, preclinical studies, and clinical translations. Different cargo fabrication techniques are also presented in the third section. Recent progresses in preclinical applications are then discussed, including tissue engineering and treatment of diseases in both therapeutic and monitoring aspects. Finally, clinical translational studies with ongoing clinical trials are summarized and reviewed. The promise of new development in nanotechnology and polysaccharide chemistry helps clinical translation of polysaccharide‐based drug delivery systems. PMID:29721408

Chem-2-Chem: A One-to-One Supportive Learning Environment for Chemistry

NASA Astrophysics Data System (ADS)

Báez-Galib, Rosita; Colón-Cruz, Héctor; Resto, Wilfredo; Rubin, Michael R.

2005-12-01

The Chem-2-Chem (C2C) tutoring mentoring program was developed at the University of Puerto Rico at Cayey, an undergraduate institution serving Hispanic students, to increase student retention and help students achieve successful general chemistry course outcomes. This program provides a supportive learning environment designed to address students' academic and emotional needs in a holistic way. Advanced chemistry students offered peer-led, personalized, and individualized learning experiences through tutoring and mentoring to approximately 21% of students enrolled in the general chemistry course. Final grades from official class lists of all general chemistry course sections were analyzed using Student's t -test, paired t -test, and χ 2 analysis. Results during the seven semesters studied show an increase of 29% in successful course outcomes defined as final letter grades of A, B, and C obtained by Chem-2-Chem participants. For each final grade, highly statistically significant differences between participants and nonparticipants were detected. There were also statistically significant differences between successful course outcomes obtained by participants and nonparticipants for each of the semesters studied. This research supports recent trends in chemical education to provide a social context for learning experiences. This peer-led learning strategy can serve as an effective model to achieve excellence in science courses at a wide range of educational institutions.

Student continuation in high school chemistry

NASA Astrophysics Data System (ADS)

Bowen, James Iddon

2006-12-01

This investigation originally intended to uncover teacher behaviors that encourage students to persist in AP Chemistry in a typical urban Texas high school. As the investigation progressed, however, alternative reasons were sought for the persistence of some students when it became apparent that teacher behaviors might not be a factor in the decision to select AP Chemistry at the school under observation. In response to this, "Branding", a business theory which suggests certain attractive aspects of a product are promoted as a way to improve sales, is introduced as an alternative way of thinking about persistence in chemistry. "Branding" can explain why some students continue to select chemistry in the face of disappointing teaching. It is also argued here that "Branding" can encourage more students to take chemistry in the future.

Embedded Mathematics in Chemistry: A Case Study of Students' Attitudes and Mastery

NASA Astrophysics Data System (ADS)

Preininger, Anita M.

2017-02-01

There are many factors that shape students' attitudes toward science, technology, engineering and mathematics. This exploratory study of high school students examined the effect of enriching chemistry with math on chemistry students' attitudes toward math and careers involving math. To measure student attitudes, a survey was administered before and after the 18-week chemistry class; results from the chemistry class were compared to survey results from students in an elective science class that did not emphasize mathematics. At the end of the 18-week period, only the chemistry students exhibited more positive views toward their abilities in mathematics and careers that involve mathematics, as compared to their views at the outset of the course. To ensure that chemistry mastery was not hindered by the additional emphasis on math, and that mastery on state end-of-course examinations reflected knowledge acquired during the math-intensive chemistry class, a chemistry progress test was administered at the start and end of the term. This exploratory study suggests that emphasizing mathematical approaches in chemistry may positively influence attitudes toward math in general, as well as foster mastery of chemistry content.

STATUS AND PROGRESS IN PARTICULATE MATTER FORECASTING: INITIAL APPLICATION OF THE ETA- CMAQ FORECAST MODEL

EPA Science Inventory

This presentation reviews the status and progress in forecasting particulate matter distributions. The shortcomings in representation of particulate matter formation in current atmospheric chemistry/transport models are presented based on analyses and detailed comparisons with me...

Modular and Orthogonal Synthesis of Hybrid Polymers and Networks

PubMed Central

Liu, Shuang; Dicker, Kevin T.; Jia, Xinqiao

2015-01-01

Biomaterials scientists strive to develop polymeric materials with distinct chemical make-up, complex molecular architectures, robust mechanical properties and defined biological functions by drawing inspirations from biological systems. Salient features of biological designs include (1) repetitive presentation of basic motifs; and (2) efficient integration of diverse building blocks. Thus, an appealing approach to biomaterials synthesis is to combine synthetic and natural building blocks in a modular fashion employing novel chemical methods. Over the past decade, orthogonal chemistries have become powerful enabling tools for the modular synthesis of advanced biomaterials. These reactions require building blocks with complementary functionalities, occur under mild conditions in the presence of biological molecules and living cells and proceed with high yield and exceptional selectivity. These chemistries have facilitated the construction of complex polymers and networks in a step-growth fashion, allowing facile modulation of materials properties by simple variations of the building blocks. In this review, we first summarize features of several types of orthogonal chemistries. We then discuss recent progress in the synthesis of step growth linear polymers, dendrimers and networks that find application in drug delivery, 3D cell culture and tissue engineering. Overall, orthogonal reactions and modulular synthesis have not only minimized the steps needed for the desired chemical transformations but also maximized the diversity and functionality of the final products. The modular nature of the design, combined with the potential synergistic effect of the hybrid system, will likely result in novel hydrogel matrices with robust structures and defined functions. PMID:25572255

Plasma Chemistry of Vibrationally Nonequilibrium Molecules

DTIC Science & Technology

1993-11-01

WL-TR-93-2116 PLASMA CHEMISTRY OF VIBRATIONALLY NONEQUILIBRIUM MOLECULES AD-A279 630--, J. WILLIAM RICH DEPARTMENT OF MECHANICAL ENGINEERING D THE...1AT9E L. REPORT TYPE AND DATES COVERED ONLY Man"_November 1993 Final 09 July 1990_- 08 July 1993 4 MITL AND SUBTITLE S. FUNDNG NUMERS & Plasma Chemistry of...k14. SUBIECT TERMS 15. NUMBER OF PAGES Molecular Energy Transfer; Plasma Chemistry ; Ionization; 4% Vibrational Relaxation; Nitric Oxide; Carbon

Organic Chemistry and Biology: Chemical Biology Through the Eyes of Collaboration

PubMed Central

Hruby, Victor J.

2011-01-01

From a scientific perspective, efforts to understand biology including what constitutes health and disease has become a chemical problem. However, chemists and biologists “see” the problems of understanding biology from different perspectives, and this has retarded progress in solving the problems especially as they relate to health and disease. This suggests that close collaboration between chemists and biologists is not only necessary but essential for progress in both the biology and chemistry that will provide solutions to the global questions of biology. This perspective has directed my scientific efforts for the past 45 years, and in this overview I provide my perspective of how the applications of synthetic chemistry, structural design, and numerous other chemical principles have intersected in my collaborations with biologists to provide new tools, new science, and new insights that were only made possible and fruitful by these collaborations. PMID:20000552

Chemometrics in analytical chemistry-part I: history, experimental design and data analysis tools.

PubMed

Brereton, Richard G; Jansen, Jeroen; Lopes, João; Marini, Federico; Pomerantsev, Alexey; Rodionova, Oxana; Roger, Jean Michel; Walczak, Beata; Tauler, Romà

2017-10-01

Chemometrics has achieved major recognition and progress in the analytical chemistry field. In the first part of this tutorial, major achievements and contributions of chemometrics to some of the more important stages of the analytical process, like experimental design, sampling, and data analysis (including data pretreatment and fusion), are summarised. The tutorial is intended to give a general updated overview of the chemometrics field to further contribute to its dissemination and promotion in analytical chemistry.

Role of Protein Synthesis Initiation Factors in Dietary Soy Isoflavone-Mediated Effects on Breast Cancer Progression

DTIC Science & Technology

2013-03-01

and complemented with data from the present report (recently published in the Journal of Biological Chemistry ) (6), was that the described increase in...Biological Chemistry (6). To investigate if the increased protein expression in response to equol was due to an increase in gene expression, we... Chemistry . Volume 50, Number, 10. pp.41640-50. See Appendix 12    CONCLUSION: Results with highly metastatic cancer cell lines show that the effects of

Mapping students' ideas about chemical reactions at different educational levels

NASA Astrophysics Data System (ADS)

Yan, Fan

Understanding chemical reactions is crucial in learning chemistry at all educational levels. Nevertheless, research in science education has revealed that many students struggle to understand chemical processes. Improving teaching and learning about chemical reactions demands that we develop a clearer understanding of student reasoning in this area and of how this reasoning evolves with training in the discipline. Thus, we have carried out a qualitative study using semi-structured interviews as the main data collection tool to explore students reasoning about reaction mechanism and causality. The participants of this study included students at different levels of training in chemistry: general chemistry students (n=22), organic chemistry students (n=16), first year graduate students (n=13) and Ph.D. candidates (n=14). We identified major conceptual modes along critical dimensions of analysis, and illustrated common ways of reasoning using typical cases. Main findings indicate that although significant progress is observed in student reasoning in some areas, major conceptual difficulties seem to persist even at the more advanced educational levels. In addition, our findings suggest that students struggle to integrate important concepts when thinking about mechanism and causality in chemical reactions. The results of our study are relevant to chemistry educators interested in learning progressions, assessment, and conceptual development.

Introduction of Digital Computer Technology Into the Undergraduate Chemistry Laboratory. Final Technical Report.

ERIC Educational Resources Information Center

Perone, Sam P.

The objective of this project has been the development of a successful approach for the incorporation of on-line computer technology into the undergraduate chemistry laboratory. This approach assumes no prior programing, electronics or instrumental analysis experience on the part of the student; it does not displace the chemistry content with…

A Survey of the Teaching Practices and Materials Used in Introductory College Chemistry. Final Report.

ERIC Educational Resources Information Center

Dodson, B.C.

Surveyed were current objectives, teaching methods and teaching materials used in introductory college chemistry. Six general objectives were identified: (1) to develop the ability to do critical thinking, (2) to make the students familiar with the facts, principles, and concepts of chemistry, (3) to help the students understand the nature of…

A priori and a posteriori analyses of the flamelet/progress variable approach for supersonic combustion

NASA Astrophysics Data System (ADS)

Saghafian, Amirreza; Pitsch, Heinz

2012-11-01

A compressible flamelet/progress variable approach (CFPV) has been devised for high-speed flows. Temperature is computed from the transported total energy and tabulated species mass fractions and the source term of the progress variable is rescaled with pressure and temperature. The combustion is thus modeled by three additional scalar equations and a chemistry table that is computed in a pre-processing step. Three-dimensional direct numerical simulation (DNS) databases of reacting supersonic turbulent mixing layer with detailed chemistry are analyzed to assess the underlying assumptions of CFPV. Large eddy simulations (LES) of the same configuration using the CFPV method have been performed and compared with the DNS results. The LES computations are based on the presumed subgrid PDFs of mixture fraction and progress variable, beta function and delta function respectively, which are assessed using DNS databases. The flamelet equation budget is also computed to verify the validity of CFPV method for high-speed flows.

[The recent research progress of chemistry of marine natural products].

PubMed

Shi, Qing-wen; Li, Li-geng; Wang, Yu-fang; Huo, Chang-hong; Zhang, Man-li

2010-10-01

Ocean is a unique and excellent resource that provides a diverse array of intriguing natural products. Marine natural products have demonstrated significant and extremely potent biological activities and have captured the attention of natural products chemists in the past few decades. It is increasingly recognized that a wealth of fascinating natural products and novel chemical entities will play a dominant role in the discovery of useful leads for the development of pharmaceutical agents and provide useful probes to lead to breakthroughs in a variety of life-science fields. This article focused on the research progress of chemistry of marine natural products in recent five years.

Pierre-Joseph Macquer: Chemistry in the French Enlightenment.

PubMed

Lehman, Christine

2014-01-01

Despite recent studies of chemistry courses and of academic research at the beginning of the eighteenth century, the perception of chemistry in the French Enlightenment has often been overshadowed by Lavoisier's works. This article proposes three specific case studies selected from Pierre Joseph Macquer's (1718-84) rich career to show the continuous evolution of chemistry throughout the century: medicinal chemistry through the application of the Comte de La Garaye's metallic salt solutions, the emergence of industrial chemistry through a few of Macquer's evaluations at the Bureau du Commerce, and finally communal academic research through the experiments on diamonds using Tschirnhaus's lens. These examples attempt to illustrate the innovative, creative, dynamic, multicultural, and multifaceted chemistry of the Enlightenment.

Investigating macroscopic, submicroscopic, and symbolic connections in a college-level general chemistry laboratory

NASA Astrophysics Data System (ADS)

Thadison, Felicia Culver

Explanations of chemical phenomena rely on understanding the behavior of submicroscopic particles. Because this level is "invisible," it is described using symbols such as models, diagrams and equations. For this reason, students often view chemistry as a "difficult" subject. The laboratory offers a unique opportunity for the students to experience chemistry macroscopically as well as symbolically. The purpose of this investigation was to determine how chemistry lab students explained chemical phenomenon on the macroscopic, submicroscopic, and representational/symbolic level. The participants were undergraduate students enrolled in an introductory level general chemistry lab course. Students' background information (gender, the number of previous chemistry courses), scores on final exams, and final average for the course were collected. Johnstone's triangle of representation guided the design and implementation of this study. A semi-structured interview was also conducted to bring out student explanations. The questionnaires required students to draw a molecule of water, complete acid base reaction equations, represent, submicroscopically, the four stages of an acid-base titration, and provide definitions of various terms. Students were able represent the submicroscopic level of water. Students were not able to represent the submicroscopic level of the reaction between an acid and a base. Students were able to represent the macroscopic level of an acid base reaction. Students were able to symbolically represent the reaction of an acid and a base. These findings indicate that students can use all three levels of chemical representation. However, students showed an inability to connect the levels in relation to acid-base chemistry. There was no relationship between a student's ability to use the levels and his or her final score in the course.

Contribution of radiation chemistry to the study of metal clusters.

PubMed

Belloni, J

1998-11-01

Radiation chemistry dates from the discovery of radioactivity one century ago by H. Becquerel and P. and M. Curie. The complex phenomena induced by ionizing radiation have been explained progressively. At present, the methodology of radiation chemistry, particularly in the pulsed mode, provides a powerful means to study not only the early processes after the energy absorption, but more generally a broad diversity of chemical and biochemical reaction mechanisms. Among them, the new area of metal cluster chemistry illustrates how radiation chemistry contributed to this field in suggesting fruitful original concepts, in guiding and controlling specific syntheses, and in the detailed elaboration of the mechanisms of complex and long-unsolved processes, such as the dynamics of nucleation, electron transfer catalysis and photographic development.

Measuring restoration progress using pore- and surface-water chemistry across a chronosequence of formerly afforested blanket bogs.

PubMed

Gaffney, Paul P J; Hancock, Mark H; Taggart, Mark A; Andersen, Roxane

2018-08-01

During the restoration of degraded bogs and other peatlands, both habitat and functional recovery can be closely linked with nutrient cycling, which is reflected in pore- and surface-water chemistry. Several peatland restoration studies have shown that the time required for recovery of target conditions is slow (>10 years); for heavily-impacted, drained and afforested peatlands of northern Scotland, recovery time is unknown. We monitored pore- and surface-water chemistry across a chronosequence of formerly drained, afforested bog restoration sites spanning 0-17 years, using a space-for-time substitution, and compared them with open blanket bog control sites. Our aims were to measure rate of recovery towards bog conditions and to identify the best suite of water chemistry variables to indicate recovery. Our results show progress in recovery towards bog conditions over a 0-17 year period post-restoration. Elements scavenged by trees (Mg, Na, S) completely recovered within that period. Many water chemistry variables were affected by the restoration process itself, but recovered within 11 years, except ammonium (NH 4 + ), Zn and dissolved organic carbon (DOC) which remained elevated (when compared to control bogs) 17 years post restoration. Other variables did not completely recover (water table depth (WTD), pH), exhibiting what we term "legacy" effects of drainage and afforestation. Excess N and a lowered WTD are likely to slow the recovery of bog vegetation including key bog plants such as Sphagnum mosses. Over 17 years, we measured near-complete recovery in the chemistry of surface-water and deep pore-water but limited progress in shallow pore-water. Our results suggest that at least >17 years are required for complete recovery of water chemistry to bog conditions. However, we expect that newer restoration methods including conifer harvesting (stem plus brash) and the blocking of plough furrows (to increase the WTD) are likely to accelerate the restoration process (albeit at greater cost); this should be evaluated in future studies. We conclude that monitoring pore- and surface-water chemistry is useful in terms of indicating recovery towards bog conditions and we recommend monitoring WTD, pH, conductivity, Ca, NH 4 + , phosphate (PO 4 3- ), K, DOC, Al and Zn as key variables. Copyright © 2018 Elsevier Ltd. All rights reserved.

Usefulness of Analytical Research: Rethinking Analytical R&D&T Strategies.

PubMed

Valcárcel, Miguel

2017-11-07

This Perspective is intended to help foster true innovation in Research & Development & Transfer (R&D&T) in Analytical Chemistry in the form of advances that are primarily useful for analytical purposes rather than solely for publishing. Devising effective means to strengthen the crucial contribution of Analytical Chemistry to progress in Chemistry, Science & Technology, and Society requires carefully examining the present status of our discipline and also identifying internal and external driving forces with a potential adverse impact on its development. The diagnostic process should be followed by administration of an effective therapy and supported by adoption of a theragnostic strategy if Analytical Chemistry is to enjoy a better future.

Teaching Chemistry in a Spiral Progression Approach: Lessons from Science Teachers in the Philippines

ERIC Educational Resources Information Center

Orbe, Joymie R.; Espinosa, Allen A.; Datukan, Janir T.

2018-01-01

As the Philippines moves towards implementing the K-12 curriculum, there has been a mismatch in teacher preparation in science. The present teacher education curriculum prepares science teachers to specialise in a specific field (e.g. integrated science, biology, chemistry, and physics). However, in the K-12 curriculum, they are required to teach…

Eppur Si Muove! The 2013 Nobel Prize in Chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Jeremy C.; Roux, Benoit

2013-12-03

The 2013 Nobel Prize in Chemistry has been awarded to Martin Karplus, Michael Levitt, and Arieh Warshel for their work on developing computational methods to study complex chemical systems. Hence, their work has led to mechanistic critical insights into chemical systems both large and small and has enabled progress in a number of different fields, including structural biology.

23 CFR 140.609 - Progress and final vouchers.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false Progress and final vouchers. 140.609 Section 140.609 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PAYMENT PROCEDURES REIMBURSEMENT Reimbursement for Bond Issue Projects § 140.609 Progress and final vouchers. (a) Progress vouchers may be...

23 CFR 140.609 - Progress and final vouchers.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false Progress and final vouchers. 140.609 Section 140.609 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PAYMENT PROCEDURES REIMBURSEMENT Reimbursement for Bond Issue Projects § 140.609 Progress and final vouchers. (a) Progress vouchers may be...

23 CFR 140.609 - Progress and final vouchers.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Progress and final vouchers. 140.609 Section 140.609 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PAYMENT PROCEDURES REIMBURSEMENT Reimbursement for Bond Issue Projects § 140.609 Progress and final vouchers. (a) Progress vouchers may be...

23 CFR 140.609 - Progress and final vouchers.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Progress and final vouchers. 140.609 Section 140.609 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PAYMENT PROCEDURES REIMBURSEMENT Reimbursement for Bond Issue Projects § 140.609 Progress and final vouchers. (a) Progress vouchers may be...

Significant steps in the evolution of analytical chemistry--is the today's analytical chemistry only chemistry?

PubMed

Karayannis, Miltiades I; Efstathiou, Constantinos E

2012-12-15

In this review the history of chemistry and specifically the history and the significant steps of the evolution of analytical chemistry are presented. In chronological time spans, covering the ancient world, the middle ages, the period of the 19th century, and the three evolutional periods, from the verge of the 19th century to contemporary times, it is given information for the progress of chemistry and analytical chemistry. During this period, analytical chemistry moved gradually from its pure empirical nature to more rational scientific activities, transforming itself to an autonomous branch of chemistry and a separate discipline. It is also shown that analytical chemistry moved gradually from the status of exclusive serving the chemical science, towards serving, the environment, health, law, almost all areas of science and technology, and the overall society. Some recommendations are also directed to analytical chemistry educators concerning the indispensable nature of knowledge of classical analytical chemistry and the associated laboratory exercises and to analysts, in general, why it is important to use the chemical knowledge to make measurements on problems of everyday life. Copyright © 2012 Elsevier B.V. All rights reserved.

Open Data, Open Source and Open Standards in chemistry: The Blue Obelisk five years on

PubMed Central

2011-01-01

Background The Blue Obelisk movement was established in 2005 as a response to the lack of Open Data, Open Standards and Open Source (ODOSOS) in chemistry. It aims to make it easier to carry out chemistry research by promoting interoperability between chemistry software, encouraging cooperation between Open Source developers, and developing community resources and Open Standards. Results This contribution looks back on the work carried out by the Blue Obelisk in the past 5 years and surveys progress and remaining challenges in the areas of Open Data, Open Standards, and Open Source in chemistry. Conclusions We show that the Blue Obelisk has been very successful in bringing together researchers and developers with common interests in ODOSOS, leading to development of many useful resources freely available to the chemistry community. PMID:21999342

Biosynthetic inorganic chemistry.

PubMed

Lu, Yi

2006-08-25

Inorganic chemistry and biology can benefit greatly from each other. Although synthetic and physical inorganic chemistry have been greatly successful in clarifying the role of metal ions in biological systems, the time may now be right to utilize biological systems to advance coordination chemistry. One such example is the use of small, stable, easy-to-make, and well-characterized proteins as ligands to synthesize novel inorganic compounds. This biosynthetic inorganic chemistry is possible thanks to a number of developments in biology. This review summarizes the progress in the synthesis of close models of complex metalloproteins, followed by a description of recent advances in using the approach for making novel compounds that are unprecedented in either inorganic chemistry or biology. The focus is mainly on synthetic "tricks" learned from biology, as well as novel structures and insights obtained. The advantages and disadvantages of this biosynthetic approach are discussed.

Final Progress Report for Award DE-FG07-05ID14637.pdf

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cathy Dixon

2012-03-09

2004-2011 Final Report for AFCI University Fellowship Program. The goal of this effort was to be supportive of university students and university programs - particularly those students and programs that will help to strengthen the development of nuclear-related fields. The program also supported the stability of the nuclear infrastructure and developed research partnerships that are helping to enlarge the national nuclear science technology base. In this fellowship program, the U.S. Department of Energy sought master's degree students in nuclear, mechanical, or chemical engineering, engineering/applied physics, physics, chemistry, radiochemistry, or fields of science and engineering applicable to the AFCI/Gen IV/GNEP missionsmore » in order to meet future U.S. nuclear program needs. The fellowship program identified candidates and selected full time students of high-caliber who were taking nuclear courses as part of their degree programs. The DOE Academic Program Managers encouraged fellows to pursue summer internships at national laboratories and supported the students with appropriate information so that both the fellows and the nation's nuclear energy objectives were successful.« less

Time-dependent interstellar chemistry

NASA Technical Reports Server (NTRS)

Glassgold, A. E.

1985-01-01

Some current problems in interstellar chemistry are considered in the context of time-dependent calculations. The limitations of steady-state models of interstellar gas-phase chemistry are discussed, and attempts to chemically date interstellar clouds are reviewed. The importance of studying the physical and chemical properties of interstellar dust is emphasized. Finally, the results of a series of studies of collapsing clouds are described.

Survey of application of radiation to preparative chemistry

NASA Technical Reports Server (NTRS)

Philipp, W. H.

1973-01-01

The use of radiation for preparative chemistry in liquid solutions is investigated. General principles are presented and preparations involving reduction, oxidation, polymerization, and decomposition are given. The use of various solvents, water, other inorganic liquids and organic liquids for this purpose is discussed. Finally, a commentary is made on some specific applications where radiation chemistry as a preparative technique may be useful.

Case Studies in Systems Chemistry. Final Report. [Includes Complete Case Study, Carboxylic Acid Equilibria

ERIC Educational Resources Information Center

Fleck, George

This publication was produced as a teaching tool for college chemistry. The book is a text for a computer-based unit on the chemistry of acid-base titrations, and is designed for use with FORTRAN or BASIC computer systems, and with a programmable electronic calculator, in a variety of educational settings. The text attempts to present computer…

Using the First Exam for Student Placement in Beginning Chemistry Courses

ERIC Educational Resources Information Center

Mills, Pamela; Sweeney, William; Bonner, Sarah M.

2009-01-01

The first exam in a typical first-semester general chemistry course is used to identify students at risk of failing the course. The performance at Hunter College of 667 students on the first exam in general chemistry in seven different classes between fall 2000 and fall 2005 was correlated with the students' final score in the course. The…

Chemistry 300. Administration Manual for Supervising Teachers, Provincial Examination, Answer Key--Multiple-Choice and Written-Answer Questions, and Provincial Summary Report = Chimie 300. Guide d'administration a l'intention des surveillants d'examen, Examen provincial, Cle de correction--Questions choix multiple et Questions responses ouvertes, et Rapport sommaire provincial.

ERIC Educational Resources Information Center

Manitoba Dept. of Education and Training, Winnipeg.

This collection of manuals contains the Manitoba Provincial Chemistry Examination for students seeking credit in Senior 4 Chemistry (Chemistry 300) and instructions for its use and grading. The examination is based on the Core Topics of the Senior 4 Chemistry course and accounts for 30% of the student's final grade in the course. The examination…

Dynamic combinatorial libraries: new opportunities in systems chemistry.

PubMed

Hunt, Rosemary A R; Otto, Sijbren

2011-01-21

Combinatorial chemistry is a tool for selecting molecules with special properties. Dynamic combinatorial chemistry started off aiming to be just that. However, unlike ordinary combinatorial chemistry, the interconnectedness of dynamic libraries gives them an extra dimension. An understanding of these molecular networks at systems level is essential for their use as a selection tool and creates exciting new opportunities in systems chemistry. In this feature article we discuss selected examples and considerations related to the advanced exploitation of dynamic combinatorial libraries for their originally conceived purpose of identifying strong binding interactions. Also reviewed are examples illustrating a trend towards increasing complexity in terms of network behaviour and reversible chemistry. Finally, new applications of dynamic combinatorial chemistry in self-assembly, transport and self-replication are discussed.

University of Illinois at Urbana-Champaign, Materials Research Laboratory progress report for FY 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1992-07-01

This interdisciplinary laboratory in the College of Engineering support research in areas of condensed matter physics, solid state chemistry, and materials science. These research programs are developed with the assistance of faculty, students, and research associates in the departments of Physics, Materials Science and Engineering, chemistry, Chemical Engineering, Electrical Engineering, Mechanical Engineering, and Nuclear Engineering.

25th anniversary article: progress in chemistry and applications of functional indigos for organic electronics.

PubMed

Głowacki, Eric Daniel; Voss, Gundula; Sariciftci, Niyazi Serdar

2013-12-17

Indigo and its derivatives are dyes and pigments with a long and distinguished history in organic chemistry. Recently, applications of this 'old' structure as a functional organic building block for organic electronics applications have renewed interest in these molecules and their remarkable chemical and physical properties. Natural-origin indigos have been processed in fully bio-compatible field effect transistors, operating with ambipolar mobilities up to 0.5 cm(2) /Vs and air-stability. The synthetic derivative isoindigo has emerged as one of the most successful building-blocks for semiconducting polymers for plastic solar cells with efficiencies > 5%. Another isomer of indigo, epindolidione, has also been shown to be one of the best reported organic transistor materials in terms of mobility (∼2 cm(2) /Vs) and stability. This progress report aims to review very recent applications of indigoids in organic electronics, but especially to logically bridge together the hereto independent research directions on indigo, isoindigo, and other materials inspired by historical dye chemistry: a field which was the root of the development of modern chemistry in the first place. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanoscale “fluorescent stone”: Luminescent Calcium Fluoride Nanoparticles as Theranostic Platforms

PubMed Central

Li, Zhanjun; Zhang, Yuanwei; Huang, Ling; Yang, Yuchen; Zhao, Yang; El-Banna, Ghida; Han, Gang

2016-01-01

Calcium Fluoride (CaF2) based luminescent nanoparticles exhibit unique, outstanding luminescent properties, and represent promising candidates as nanoplatforms for theranostic applications. There is an urgent need to facilitate their further development and applications in diagnostics and therapeutics as a novel class of nanotools. Here, in this critical review, we outlined the recent significant progresses made in CaF2-related nanoparticles: Firstly, their physical chemical properties, synthesis chemistry, and nanostructure fabrication are summarized. Secondly, their applications in deep tissue bio-detection, drug delivery, imaging, cell labeling, and therapy are reviewed. The exploration of CaF2-based luminescent nanoparticles as multifunctional nanoscale carriers for imaging-guided therapy is also presented. Finally, we discuss the challenges and opportunities in the development of such CaF2-based platform for future development in regard to its theranostic applications. PMID:27877242

Boost-phase discrimination research

NASA Technical Reports Server (NTRS)

Langhoff, Stephen R.; Feiereisen, William J.

1993-01-01

The final report describes the combined work of the Computational Chemistry and Aerothermodynamics branches within the Thermosciences Division at NASA Ames Research Center directed at understanding the signatures of shock-heated air. Considerable progress was made in determining accurate transition probabilities for the important band systems of NO that account for much of the emission in the ultraviolet region. Research carried out under this project showed that in order to reproduce the observed radiation from the bow shock region of missiles in their boost phase it is necessary to include the Burnett terms in the constituent equation, account for the non-Boltzmann energy distribution, correctly model the NO formation and rotational excitation process, and use accurate transition probabilities for the NO band systems. This work resulted in significant improvements in the computer code NEQAIR that models both the radiation and fluid dynamics in the shock region.

Implementation of an online chemical mechanism within a global-regional atmospheric model: design and initial steps

NASA Astrophysics Data System (ADS)

Jorba, O.; Pérez, C.; Baldasano, J. M.

2009-04-01

Chemical processes in air quality modelling systems are usually treated independently from the meteorological models. This approach is computationally attractive since off-line chemical transport simulations only require a single meteorological dataset to produce many chemical simulations. However, this separation of chemistry and meteorology produces a loss of important information about atmospheric processes and does not allow for feedbacks between chemistry and meteorology. To take into account such processes current models are evolving to an online coupling of chemistry and meteorology to produce consistent chemical weather predictions. The Earth Sciences Department of the Barcelona Supercomputing Center (BSC) develops the NMMB/BSC-DUST (Pérez et al., 2008), an online dust model within the global-regional NCEP/NMMB numerical weather prediction model (Janjic and Black, 2007) under development at National Centers for Environmental Prediction (NCEP). Current implementation is based on the well established regional dust model and forecast system DREAM (Nickovic et al., 2001). The most relevant characteristics of NMMB/BSC-DUST are its on-line coupling of the dust scheme with the meteorological driver, the wide range of applications from meso to global scales, and the inclusion of dust radiative effects allowing feedbacks between aerosols and meteorology. In order to complement such development, BSC works also in the implementation of a fully coupled online chemical mechanism within NMMB/BSC-DUST. The final objective is to develop a fully chemical weather prediction system able to resolve gas-aerosol-meteorology interactions from global to local scales. In this contribution we will present the design of the chemistry coupling and the current progress of its implementation. Following the NCEP/NMMB approach, the chemistry part will be coupled through the Earth System Modeling Framework (ESMF) as a pluggable component. The chemical mechanism and chemistry solver is based on the Kinetic PreProcessor KPP (Sandu and Sander, 2006) package with the main purpose to maintain a wide flexibility when configuring the model. Such approach will allow using a simple general chemical mechanism for global applications or a more complex mechanism for regional to local applications at higher resolution. REFERENCES Janjic, Z.I., and Black, T.L., 2007. An ESMF unified model for a broad range of spatial and temporal scales, Geophysical Research Abstracts, 9, 05025. Nickovic, S., Papadopoulos, A., Kakaliagou, O., and Kallos, G., 2001. Model for prediciton of desert dust cycle in the atmosphere. J. Geophys. Res., 106, 18113-18129. Pérez, C., Haustein, K., Janjic, Z.I., Jorba, O., Baldasano, J.M., Black, T.L., and Nickovic, S., 2008. An online dust model within the meso to global NMMB: current progress and plans. AGU Fall Meeting, San Francisco, A41K-03, 2008. Sandu, A., and Sander, R., 2006. Technical note:Simulating chemical systems in Fortran90 and Matlab with the Kinetic PreProcessor KPP-2.1. Atmos. Chem. and Phys., 6, 187-195.

Ab Initio-Based Predictions of Hydrocarbon Combustion Chemistry

DTIC Science & Technology

2015-07-15

There are two prime objectives of the research. One is to develop and apply efficient methods for using ab initio potential energy surfaces (PESs...31-Mar-2015 Approved for Public Release; Distribution Unlimited Final Report: Ab Initio -Based Predictions of Hydrocarbon Combustion Chemistry The...Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 hydrocarbon combustion, ab initio quantum chemistry, potential energy surfaces, chemical

The University of Houston Libraries' Chemistry Research Information Service: A Research Support Service Based on End-User Searching and Document Delivery. Final Report.

ERIC Educational Resources Information Center

Bailey, Charles W., Jr.

This report on a funded project that established a chemistry research information service for researchers in the University of Houston's chemistry department provides detailed descriptions of the three objectives of the project, together with an explanation of how each objective was/is to be accomplished. These objectives were/are: (1) to document…

Water chemistry: fifty years of change and progress.

PubMed

Brezonik, Patrick L; Arnold, William A

2012-06-05

Water chemistry evolved from early foundations in several related disciplines. Although it is difficult to associate a precise date to its founding, several events support the argument that the field as we know it today developed in the mid-20th century--at the dawn of the "environmental era"--that is, ∼1960. The field in its modern incarnation thus is about 50 years old. In celebration of this half-centenary, we examine here the origins of water chemistry, how the field has changed over the past 50 years, and the principal driving forces for change, focusing on both the "practice" of water chemistry and ways that teaching the subject has evolved.

[Commentary on the Nobel Prize that has been granted in Medicine-Physiology, Chemistry and Physics to noteable investigators].

PubMed

Zárate, Arturo; Apolinar, Leticia Manuel; Saucedo, Renata; Basurto, Lourdes

2015-01-01

The Nobel Prize was established by Alfred Nobel in 1901 to award people who have made outstanding achievements in physics, chemistry and medicine. So far, from 852 laureates, 45 have been female. Marie Curie was the first woman to receive the Nobel Prize in 1903 for physics and eight years later also for chemistry It is remarkable that her daughter Irene and her husband also received the Nobel Prize for chemistry in 1935. Other two married couples, Cori and Moser, have also been awarded the Nobel Prize. The present commentary attempts to show the female participation in the progress of scientific activities.

Perception of the Relevance of Organic Chemistry in a German Pharmacy Students’ Course

PubMed Central

Wehle, Sarah

2016-01-01

Objective. To investigate German pharmacy students’ attitudes toward the relevance of organic chemistry training in Julius Maximilian University (JMU) of Würzburg with regard to subsequent courses in the curricula and in later prospective career options. Methods. Surveys were conducted in the second-year organic chemistry course (50 participants) as well as during the third-year and fourth-year lecture cycle on medicinal and pharmaceutical chemistry (66 participants) in 2014. Results. Students’ attitudes were surprisingly consistent throughout the progress of the degree course. Students considered organic chemistry very relevant to the pharmacy study program (95% junior and 97% senior students), and of importance for their future pharmacy program (88% junior and 94% senior students). With regard to prospective career options, the perceived relevance was considerably lower and attitudes were less homogenous. Conclusions. German pharmacy students at JMU Würzburg consider organic chemistry of high relevance for medicinal chemistry and other courses in JMU’s pharmacy program. PMID:27170811

Perception of the Relevance of Organic Chemistry in a German Pharmacy Students' Course.

PubMed

Wehle, Sarah; Decker, Michael

2016-04-25

Objective. To investigate German pharmacy students' attitudes toward the relevance of organic chemistry training in Julius Maximilian University (JMU) of Würzburg with regard to subsequent courses in the curricula and in later prospective career options. Methods. Surveys were conducted in the second-year organic chemistry course (50 participants) as well as during the third-year and fourth-year lecture cycle on medicinal and pharmaceutical chemistry (66 participants) in 2014. Results. Students' attitudes were surprisingly consistent throughout the progress of the degree course. Students considered organic chemistry very relevant to the pharmacy study program (95% junior and 97% senior students), and of importance for their future pharmacy program (88% junior and 94% senior students). With regard to prospective career options, the perceived relevance was considerably lower and attitudes were less homogenous. Conclusions. German pharmacy students at JMU Würzburg consider organic chemistry of high relevance for medicinal chemistry and other courses in JMU's pharmacy program.

High school chemistry students' learning of the elements, structure, and periodicity of the periodic table: Contributions of inquiry-based activities and exemplary graphics

NASA Astrophysics Data System (ADS)

Roddy, Knight Phares, Jr.

The main research question of this study was: How do selected high school chemistry students' understandings of the elements, structure, and periodicity of the Periodic Table change as they participate in a unit study consisting of inquiry-based activities emphasizing construction of innovative science graphics? The research question was answered using a multiple case study/mixed model design which employed elements of both qualitative and quantitative methodologies during data collection and analyses. The unit study was conducted over a six-week period with 11th -grade students enrolled in a chemistry class. A purposive sample of six students from the class was selected to participate in interviews and concept map coconstruction (Wandersee & Abrams, 1993) periodically across the study. The progress of the selected students of the case study was compared to the progress of the class as a whole. The students of the case study were also compared to a group of high school chemistry students at a comparative school. The results show that the students from both schools left traditional instruction on the periodic table (lecture and textbook activities) with a very limited understanding of the topic. It also revealed that the inquiry-based, visual approach of the unit study helped students make significant conceptual progress in their understanding of the periodic table. The pictorial periodic table (which features photographs of the elements), used in conjunction with the graphic technique of data mapping, enhanced students understanding of the patterns of the physical properties of the elements on the periodic table. The graphic technique of compound mapping helped students learn reactivity patterns between types and groups of elements on the periodic table. The recreation of the periodic table with element cards created from the pictorial periodic table helped students progress in their understanding of periodicity and its key concepts. The Periodic Table Literacy Rubric (PTLR) proved to be a valuable tool for assessing students' conceptual progress, and helped to identify a critical juncture in the learning of periodicity. In addition, the PTLR rubric's historical-conceptual design demonstrates how the history of science can be used to inform today's science teaching.

Theoretical studies in interstellar cloud chemistry

NASA Technical Reports Server (NTRS)

Chiu, Y. T.; Prasad, S. S.

1993-01-01

This final report represents the completion of the three tasks under the purchase order no. SCPDE5620,1,2F. Chemical composition of gravitationally contracting, but otherwise quiescent, interstellar clouds and of interstellar clouds traversed by high velocity shocks, were modeled in a comprehensive manner that represents a significant progress in modeling these objects. The evolutionary chemical modeling, done under this NASA contract, represents a notable advance over the 'classical' fixed condition equilibrium models because the evolutionary models consider not only the chemical processes but also the dynamical processes by which the dark interstellar clouds may have assumed their present state. The shock calculations, being reported here, are important because they extend the limited chemical composition derivable from dynamical calculations for the total density and temperature structures behind the shock front. In order to be tractable, the dynamical calculations must severely simplify the chemistry. The present shock calculations take the shock profiles from the dynamical calculations and derive chemical composition in a comprehensive manner. The results of the present modeling study are still to be analyzed with reference to astronomical observational data and other contemporary model predictions. As far as humanly possible, this analysis will be continued with CRE's (Creative Research Enterprises's) IR&D resources, until a sponsor is found.

Grade 12 Diploma Examination: Chemistry 30. June 1988 = Examen en vue du Diplome Douzieme Annee: Chimie 30. Juin 1988.

ERIC Educational Resources Information Center

Alberta Dept. of Education, Edmonton.

Chemistry 30 is a 12th-grade chemistry course for students in Alberta, Canada. This document is the final test for the course. Intended for administration during June, 1988, it contains 56 multiple-choice questions and three written-response questions. Two-and-one-half hours are allowed for completing the test. No answer key is included since…

Grade 12 Diploma Examination: Chemistry 30. June 1986. = Examen en vue du Diplome Douzieme Annee: Chimie 30. Juin 1986.

ERIC Educational Resources Information Center

Alberta Dept. of Education, Edmonton.

Chemistry 30 is a twelfth-grade chemistry course for students in Alberta, Canada. This document is a final test for the course. Both English and French versions of the test are provided. Intended for administration during June 1986, it contains 56 multiple-choice questions and three written-response problems. Two-and-one-half hours are allowed for…

Chemistry for the Life Sciences. An Instructor Resource Guide. Appendix to a Final Report on the Paraprofessional Rurally Oriented Family Home Health Training Program.

ERIC Educational Resources Information Center

Odom, H. Clyde; Myer, Donna Foster

This instructor's resource guide, one in a series of products from a project to develop an associate degree program for paraprofessional rural family health promoters, deals with teaching chemistry for the life sciences. Covered in the first section of the volume are the role of chemistry in rural health promotional training, general objectives…

The IUPAC International Congresses of Pesticide Chemistry (1963-2014) and Pest Management Science: a half-century of progress.

PubMed

Brooks, Gerald T

2014-08-01

As we approach the 2014 San Francisco IUPAC Pesticide Chemistry Congress, we reflect on the 51 years of such congresses every 4 years since 1963. Meanwhile, our journal, Pesticide Science/Pest Management Science, has in parallel continually published relevant science for nearly as long (44 years from 1970). © 2014 Society of Chemical Industry.

An Analysis of 16-17-Year-Old Students' Understanding of Solution Chemistry Concepts Using a Two-Tier Diagnostic Instrument

ERIC Educational Resources Information Center

Adadan, Emine; Savasci, Funda

2012-01-01

This study focused on the development of a two-tier multiple-choice diagnostic instrument, which was designed and then progressively modified, and implemented to assess students' understanding of solution chemistry concepts. The results of the study are derived from the responses of 756 Grade 11 students (age 16-17) from 14 different high schools…

A One-Pot Synthesis of m-Terphenyls: A Guided Exploration of Reaction Chemistry, Chromatography, and Spectroscopy. A Miniproject for the Advanced Organic Chemistry Laboratory

NASA Astrophysics Data System (ADS)

Anam, Kishorekumar T.; Curtis, Michael P.; Irfan, Muhammad J.; Johnson, Michael P.; Royer, Andrew P.; Shahmohammadi, Kianor; Vinod, Thottumkara K.

2002-05-01

This four-week project-based laboratory exercise, developed for advanced organic chemistry students, involves a one-pot synthesis of m-terphenyls. Chemistry of aryl diazonium salts and Grignard reagents and reactivity of aryne intermediates toward nucleophilic reagents form the reaction chemistry basis for the project. The project exposes students to a number of important laboratory techniques (thin-layer chromatography, gas chromatography-mass spectrometry, and column chromatography) for monitoring reaction progress and product isolation. A variety of spectroscopic techniques, including IR, 1H NMR, 13C NMR, and attached proton test are used for product characterization. Students are also introduced to a useful empirical relationship to help predict (with considerable accuracy) the 13C chemical shift values of carbon atoms of substituted benzenes.

Investigation Of Student Learning In Thermodynamics And Implications For Instruction In Chemistry And Engineering

NASA Astrophysics Data System (ADS)

Meltzer, David E.

2007-01-01

As part of an investigation into student learning of thermodynamics, we have probed the reasoning of students enrolled in introductory and advanced courses in both physics and chemistry. A particular focus of this work has been put on the learning difficulties encountered by physics, chemistry, and engineering students enrolled in an upper-level thermal physics course that included many topics also covered in physical chemistry courses. We have explored the evolution of students' understanding as they progressed from the introductory course through more advanced courses. Through this investigation we have gained insights into students' learning difficulties in thermodynamics at various levels. Our experience in addressing these learning difficulties may provide insights into analogous pedagogical issues in upper-level courses in both engineering and chemistry which focus on the theory and applications of thermodynamics.

Dragonfly: In Situ Exploration of Titan's Organic Chemistry and Habitability

NASA Astrophysics Data System (ADS)

Turtle, E. P.; Barnes, J. W.; Trainer, M. G.; Lorenz, R. D.

2017-12-01

Titan's abundant complex carbon-rich chemistry, interior ocean, and past presence of liquid water on the surface make it an ideal destination to study prebiotic chemical processes and document the habitability of an extraterrestrial environment. Titan exploration is a high science priority due to the level of organic synthesis that it supports. Moreover, opportunities for organics to have interacted with liquid water at the surface (e.g., in impact melt sheets) increase the potential for chemical processes to progress further, providing an unparalleled opportunity to investigate prebiotic chemistry, as well as to search for signatures of potential water-based or even hydrocarbon-based life. The diversity of Titan's surface materials and environments drives the scientific need to be able to sample a variety of locations, thus mobility is key for in situ measurements. Titan's atmosphere is 4 times denser than Earth's reducing the wing/rotor area required to generate a given amount of lift, and the low gravity reduces the required magnitude of lift, making heavier-than-air mobility highly efficient. Dragonfly is a rotorcraft lander mission proposed to NASA's New Frontiers Program to take advantage of Titan's unique natural laboratory to understand how far chemistry can progress in environments that provide key ingredients for life. Measuring the compositions of materials in different environments will reveal how far organic chemistry has progressed. Surface material can be sampled into a mass spectrometer to identify the chemical components available and processes at work to produce biologically relevant compounds. Bulk elemental surface composition can be determined by a neutron-activated gamma-ray spectrometer. Meteorology measurements can characterize Titan's atmosphere and diurnal and spatial variations therein. Geologic features can be characterized via remote-sensing observations, which also provide context for samples. Seismic sensing can probe subsurface structure and activity. In addition to surface investigations, Dragonfly can perform measurements during flight, including atmospheric profiles and aerial observations of surface geology, which also provide sampling context and scouting for landing sites.

Surface and Interface Chemistry for Gate Stacks on Silicon

NASA Astrophysics Data System (ADS)

Frank, M. M.; Chabal, Y. J.

This chapter addresses the fundamental silicon surface science associated with the continued progress of nanoelectronics along the path prescribed by Moore's law. Focus is on hydrogen passivation layers and on ultrathin oxide films encountered during silicon cleaning and gate stack formation in the fabrication of metal-oxide-semiconductor field-effect transistors (MOSFETs). Three main topics are addressed. (i) First, the current practices and understanding of silicon cleaning in aqueous solutions are reviewed, including oxidizing chemistries and cleans leading to a hydrogen passivation layer. The dependence of the final surface termination and morphology/roughness on reactant choice and pH and the influence of impurities such as dissolved oxygen or metal ions are discussed. (ii) Next, the stability of hydrogen-terminated silicon in oxidizing liquid and gas phase environments is considered. In particular, the remarkable stability of hydrogen-terminated silicon surface in pure water vapor is discussed in the context of atomic layer deposition (ALD) of high-permittivity (high-k) gate dielectrics where water is often used as an oxygen precursor. Evidence is also provided for co-operative action between oxygen and water vapor that accelerates surface oxidation in humid air. (iii) Finally, the fabrication of hafnium-, zirconium- and aluminum-based high-k gate stacks is described, focusing on the continued importance of the silicon/silicon oxide interface. This includes a review of silicon surface preparation by wet or gas phase processing and its impact on high-k nucleation during ALD growth, and the consideration of gate stack capacitance and carrier mobility. In conclusion, two issues are highlighted: the impact of oxygen vacancies on the electrical characteristics of high-k MOS devices, and the way alloyed metal ions (such as Al in Hf-based gate stacks) in contact with the interfacial silicon oxide layer can be used to control flatband and threshold voltages.

Computational Modeling as a Design Tool in Microelectronics Manufacturing

NASA Technical Reports Server (NTRS)

Meyyappan, Meyya; Arnold, James O. (Technical Monitor)

1997-01-01

Plans to introduce pilot lines or fabs for 300 mm processing are in progress. The IC technology is simultaneously moving towards 0.25/0.18 micron. The convergence of these two trends places unprecedented stringent demands on processes and equipments. More than ever, computational modeling is called upon to play a complementary role in equipment and process design. The pace in hardware/process development needs a matching pace in software development: an aggressive move towards developing "virtual reactors" is desirable and essential to reduce design cycle and costs. This goal has three elements: reactor scale model, feature level model, and database of physical/chemical properties. With these elements coupled, the complete model should function as a design aid in a CAD environment. This talk would aim at the description of various elements. At the reactor level, continuum, DSMC(or particle) and hybrid models will be discussed and compared using examples of plasma and thermal process simulations. In microtopography evolution, approaches such as level set methods compete with conventional geometric models. Regardless of the approach, the reliance on empricism is to be eliminated through coupling to reactor model and computational surface science. This coupling poses challenging issues of orders of magnitude variation in length and time scales. Finally, database development has fallen behind; current situation is rapidly aggravated by the ever newer chemistries emerging to meet process metrics. The virtual reactor would be a useless concept without an accompanying reliable database that consists of: thermal reaction pathways and rate constants, electron-molecule cross sections, thermochemical properties, transport properties, and finally, surface data on the interaction of radicals, atoms and ions with various surfaces. Large scale computational chemistry efforts are critical as experiments alone cannot meet database needs due to the difficulties associated with such controlled experiments and costs.

Progress in the medicinal chemistry of silicon: C/Si exchange and beyond.

PubMed

Fujii, Shinya; Hashimoto, Yuichi

2017-04-01

Application of silyl functionalities is one of the most promising strategies among various 'elements chemistry' approaches for the development of novel and distinctive drug candidates. Replacement of one or more carbon atoms of various biologically active compounds with silicon (so-called sila-substitution) has been intensively studied for decades, and is often effective for alteration of activity profile and improvement of metabolic profile. In addition to simple C/Si exchange, several novel approaches for utilizing silicon in medicinal chemistry have been suggested in recent years, focusing on the intrinsic differences between silicon and carbon. Sila-substitution offers great potential for enlarging the chemical space of medicinal chemistry, and provides many options for structural development of drug candidates.

Click Chemistry for Analysis of Cell Proliferation in Flow Cytometry.

PubMed

Clarke, Scott T; Calderon, Veronica; Bradford, Jolene A

2017-10-02

The measurement of cellular proliferation is fundamental to the assessment of cellular health, genotoxicity, and the evaluation of drug efficacy. Labeling, detection, and quantification of cells in the synthesis phase of cell cycle progression are not only important for characterizing basic biology, but also in defining cellular responses to drug treatments. Changes in DNA replication during S-phase can provide valuable insights into mechanisms of cell growth, cell cycle kinetics, and cytotoxicity. A common method for detection of cell proliferation is the incorporation of a thymidine analog during DNA synthesis. This chapter presents a pulse labeling method using the thymidine analog, 5-ethynyl-2'-deoxyuridine (EdU), with subsequent detection by click chemistry. EdU detection using click chemistry is bio-orthogonal to most living systems and does not non-specifically label other biomolecules. Live cells are first pulsed with EdU. After antibody labeling cell surface markers, fixation, and permeabilization, the incorporated EdU is covalently labeled using click chemistry thereby identifying proliferating cells. Improvements in click chemistry allow for labeling in the presence of fluorescent proteins and phycobiliproteins without quenching due to copper. Measuring DNA replication during cell cycle progression has cell health applications in flow cytometry, fluorescence microscopy, and high content imaging. This protocol has been developed and optimized for research use only and is not suitable for use in diagnostic procedures. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

JPRS Report, Science & Technology, USSR: Chemistry.

DTIC Science & Technology

1987-07-15

dust and gas emissions from ferrous and nonferrous metallurgical facilities on vegetable crops of 42 collective farms within a 10-15 km radius...the dust and gas wastes were determined to have adverse effects on vegetable crops. Tables 3. 12172/12379 CSO: 1841/299 43 FERTILIZERS...academy’s Institute of physical-Organic Chemistry, head of the republic large-scale program " Membrana "] [Abstract] The author assesses progress in

Progression in Children's Understanding of the Matter Concept from Elementary to High School

ERIC Educational Resources Information Center

Liu, Xiufeng; Lesniak, Kathleen

2006-01-01

Adopting a neo-Piagetian conceptual framework and a phenomenographic approach, we identified students' conceptual progression pattern on matter from elementary to high school. We interviewed 54 students from Grade 1 to Grade 10 chemistry on their conceptions of substances (i.e., water, vinegar, and baking soda) and the combining of the substances.…

Mapping student thinking in chemical synthesis

NASA Astrophysics Data System (ADS)

Weinrich, Melissa

In order to support the development of learning progressions about central ideas and practices in different disciplines, we need detailed analyses of the implicit assumptions and reasoning strategies that guide students' thinking at different educational levels. In the particular case of chemistry, understanding how new chemical substances are produced (chemical synthesis) is of critical importance. Thus, we have used a qualitative research approach based on individual interviews with first semester general chemistry students (n = 16), second semester organic chemistry students (n = 15), advanced undergraduates (n = 9), first year graduate students (n = 15), and PhD candidates (n = 16) to better characterize diverse students' underlying cognitive elements (conceptual modes and modes of reasoning) when thinking about chemical synthesis. Our results reveal a great variability in the cognitive resources and strategies used by students with different levels of training in the discipline to make decisions, particularly at intermediate levels of expertise. The specific nature of the task had a strong influence on the conceptual sophistication and mode of reasoning that students exhibited. Nevertheless, our data analysis has allowed us to identify common modes of reasoning and assumptions that seem to guide students' thinking at different educational levels. Our results should facilitate the development of learning progressions that help improve chemistry instruction, curriculum, and assessment.

Impact of Defects in Powder Feedstock Materials on Microstructure of 304L and 316L Stainless Steel Produced by Additive Manufacturing

NASA Astrophysics Data System (ADS)

Morrow, Benjamin M.; Lienert, Thomas J.; Knapp, Cameron M.; Sutton, Jacob O.; Brand, Michael J.; Pacheco, Robin M.; Livescu, Veronica; Carpenter, John S.; Gray, George T.

2018-05-01

Recent work in both 304L and 316L stainless steel produced by additive manufacturing (AM) has shown that in addition to the unique, characteristic microstructures formed during the process, a fine dispersion of sub-micron particles, with a chemistry different from either the powder feedstock or the expected final material, are evident in the final microstructure. Such fine-scale features can only be resolved using transmission electron microscopy (TEM) or similar techniques. The present work uses electron microscopy to study both the initial powder feedstock and microstructures in final AM parts. Special attention is paid to the chemistry and origin of these nanoscale particles in several different metal alloys, and their impact on the final build. Comparisons to traditional, wrought material will be made.

Stable Radical Materials for Energy Applications.

PubMed

Wilcox, Daniel A; Agarkar, Varad; Mukherjee, Sanjoy; Boudouris, Bryan W

2018-06-07

Although less studied than their closed-shell counterparts, materials containing stable open-shell chemistries have played a key role in many energy storage and energy conversion devices. In particular, the oxidation-reduction (redox) properties of these stable radicals have made them a substantial contributor to the progress of organic batteries. Moreover, the use of radical-based materials in photovoltaic devices and thermoelectric systems has allowed for these emerging molecules to have impacts in the energy conversion realm. Additionally, the unique doublet states of radical-based materials provide access to otherwise inaccessible spin states in optoelectronic devices, offering many new opportunities for efficient usage of energy in light-emitting devices. Here, we review the current state of the art regarding the molecular design, synthesis, and application of stable radicals in these energy-related applications. Finally, we point to fundamental and applied arenas of future promise for these designer open-shell molecules, which have only just begun to be evaluated in full.

Calculation of State Specific Rate Coefficients for Non-Equilibrium Hypersonics Applications: from H(Psi) = E(Psi) to k(T) = A *exp(-E(sub a)/RT)

NASA Technical Reports Server (NTRS)

Jaffe, Richard; Schwenke, David; Chaban, Galina; Panesi, Marco

2014-01-01

Development of High-Fidelity Physics-Based Models to describe hypersonic flight through the atmospheres of Earth and Mars is underway at NASA Ames Research Center. The goal is to construct chemistry models of the collisional and radiative processes that occur in the bow shock and boundary layers of spacecraft during atmospheric entry that are free of empiricism. In this talk I will discuss our philosophy and describe some of our progress. Topics to be covered include thermochemistry, internal energy relaxation, collisional dissociation and radiative emission and absorption. For this work we start by solving the Schrodinger equation to obtain accurate interaction potentials and radiative properties. Then we invoke classical mechanics to compute state-specific heavy particle collision cross sections and reaction rate coefficients. Finally, phenomenological rate coefficients and relaxation times are determined from master equation solutions.

Volcanic ash-based geopolymer cements/concretes: the current state of the art and perspectives.

PubMed

Djobo, Jean Noël Yankwa; Elimbi, Antoine; Tchakouté, Hervé Kouamo; Kumar, Sanjay

2017-02-01

The progress achieved with the use of volcanic ash for geopolymer synthesis has been critically reviewed in this paper. This consists of an overview of mineralogy and chemistry of volcanic ash. The role of chemical composition and mineral contents of volcanic ash on their reactivity during geopolymerization reaction and, consequently, mechanical properties have been accessed. An attempt has been made to establish a relationship between synthesis factors and final properties. A critical assessment of some synthesis conditions has been addressed and some practical recommendations given along with suggestions of future works that have to be done. All this has shown that there are still many works such as durability tests (carbonation, freeze-thaw, resistance, etc.), life cycle analysis, etc. that need to be done in order to satisfy both suitability and sustainability criteria for a large-scale or industrial application.

Computational approaches to substrate-based cell motility

DOE PAGES

Ziebert, Falko; Aranson, Igor S.

2016-07-15

Substrate-based crawling motility of eukaryotic cells is essential for many biological functions, both in developing and mature organisms. Motility dysfunctions are involved in several life-threatening pathologies such as cancer and metastasis. Motile cells are also a natural realization of active, self-propelled ‘particles’, a popular research topic in nonequilibrium physics. Finally, from the materials perspective, assemblies of motile cells and evolving tissues constitute a class of adaptive self-healing materials that respond to the topography, elasticity, and surface chemistry of the environment and react to external stimuli. Although a comprehensive understanding of substrate-based cell motility remains elusive, progress has been achieved recentlymore » in its modeling on the whole cell level. Furthermore we survey the most recent advances in computational approaches to cell movement and demonstrate how these models improve our understanding of complex self-organized systems such as living cells.« less

Development of a MELCOR Sodium Chemistry (NAC) Package - FY17 Progress.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Louie, David; Humphries, Larry L.

This report describes the status of the development of MELCOR Sodium Chemistry (NAC) package. This development is based on the CONTAIN-LMR sodium physics and chemistry models to be implemented in MELCOR. In the past three years, the sodium equation of state as a working fluid from the nuclear fusion safety research and from the SIMMER code has been implemented into MELCOR. The chemistry models from the CONTAIN-LMR code, such as the spray and pool fire mode ls, have also been implemented into MELCOR. This report describes the implemented models and the issues encountered. Model descriptions and input descriptions are provided.more » Development testing of the spray and pool fire models is described, including the code-to-code comparison with CONTAIN-LMR. The report ends with an expected timeline for the remaining models to be implemented, such as the atmosphere chemistry, sodium-concrete interactions, and experimental validation tests .« less

75 FR 8266 - Final Clarification for Chemical Identification Describing Activated Phosphors for TSCA Inventory...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-24

... Agency's incomplete information and understanding of the chemistry involved in manufacturing activated... substance'' in relevant part as ``any organic or inorganic substance of a particular molecular identity... criteria used to assess these materials will be uniform. 3. Comment. Commenter American Chemistry Council...

Final report on International Conference on Radiationless Transitions Held at Newport Beach, California on January 3-7, 1984.

DTIC Science & Technology

1984-12-31

Ca. 90007 USA Eric C. Apel Dr. G. Comtet Department of Chemstry Department of Chemistry University of CAlifornia University of Californiai Irvine...Chicago Tempo, Az 85827 USA Chicago, Ill. 60637 USA - Professor R. Kopelman Professor S’. H. Lin Department of Chemistry Department of Chemstry . University...Nadler Department of Chemstry Ms. B. Lawrence University of Southern Calif. Department of Chemistry Los Angeles, Ca. 90007 USA University of California

Analytical Chemistry Division annual progress report for period ending December 31, 1989

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-04-01

The Analytical Chemistry Division of Oak Ridge National Laboratory (ORNL) is a large and diversified organization. As such, it serves a multitude of functions for a clientele that exists both in and outside of ORNL. These functions fall into the following general categories: Analytical Research, Development and Implementation; Programmatic Research, Development, and Utilization; and Technical Support. The Analytical Chemistry Division is organized into four major sections, each which may carry out any of the three types of work mentioned above. Chapters 1 through 4 of this report highlight progress within the four sections during the period January 1 to Decembermore » 31, 1989. A brief discussion of the division's role in an especially important environmental program is given in Chapter 5. Information about quality assurance, safety, and training programs is presented in Chapter 6, along with a tabulation of analyses rendered. Publications, oral presentations, professional activities, educational programs, and seminars are cited in Chapters 7 and 8. Approximately 69 articles, 41 proceedings, and 31 reports were published, and 151 oral presentations were given during this reporting period. Some 308,981 determinations were performed.« less

Grant Closeout Requirements and Reports

Cancer.gov

Requirements and reports to comply with grant closeout, including Final Federal Financial Report (FFR, SF425); Final Research Performance Progress Report (FRPPR); Interim Research Performance Progress Report (IRPPR); Final Invention Statement (FIS, HHS

Autophagy and TGF-Beta Antagonist Signaling in Breast Cancer Dormancy at Premetastatic Sites

DTIC Science & Technology

2015-06-01

blocking Coco and other players involved in reactivation of dormant legions. These inhibitors will be the drug leads for further medicinal chemistry and...blocking Coco and other players involved in reactivation of dormant legions. These inhibitors will be the drug leads for further medicinal chemistry and... protocol . Below we report our progress, starting with the SOW check list below followed by detailed description. Statement of Work (SOW): Task-1

Current applications and future potential for bioinorganic chemistry in the development of anticancer drugs

PubMed Central

van Rijt, Sabine H.; Sadler, Peter J.

2010-01-01

This review illustrates notable recent progress in the field of medicinal bioinorganic chemistry with many new approaches to the design of innovative metal-based anticancer drugs emerging. Current research addressing the problems associated with platinum drugs has focused on other metal-based therapeutics that have different modes of action, and on prodrug and targeting strategies in an effort to diminish the side-effects of cisplatin chemotherapy. PMID:19782150

Density functional theory across chemistry, physics and biology.

PubMed

van Mourik, Tanja; Bühl, Michael; Gaigeot, Marie-Pierre

2014-03-13

The past decades have seen density functional theory (DFT) evolve from a rising star in computational quantum chemistry to one of its major players. This Theme Issue, which comes half a century after the publication of the Hohenberg-Kohn theorems that laid the foundations of modern DFT, reviews progress and challenges in present-day DFT research. Rather than trying to be comprehensive, this Theme Issue attempts to give a flavour of selected aspects of DFT.

Driving external chemistry optimization via operations management principles.

PubMed

Bi, F Christopher; Frost, Heather N; Ling, Xiaolan; Perry, David A; Sakata, Sylvie K; Bailey, Simon; Fobian, Yvette M; Sloan, Leslie; Wood, Anthony

2014-03-01

Confronted with the need to significantly raise the productivity of remotely located chemistry CROs Pfizer embraced a commitment to continuous improvement which leveraged the tools from both Lean Six Sigma and queue management theory to deliver positive measurable outcomes. During 2012 cycle times were reduced by 48% by optimization of the work in progress and conducting a detailed workflow analysis to identify and address pinch points. Compound flow was increased by 29% by optimizing the request process and de-risking the chemistry. Underpinning both achievements was the development of close working relationships and productive communications between Pfizer and CRO chemists. Copyright © 2013 Elsevier Ltd. All rights reserved.

'Click chemistry' for diagnosis: a patent review on exploitation of its emerging trends.

PubMed

Mandhare, Anita; Banerjee, Paromita; Bhutkar, Smita; Hirwani, Rajkumar

2014-12-01

Click chemistry is the novel synthetic approach towards developing reactions with large thermodynamic driving forces to give almost complete conversion of new molecular reagents to a single product. Thus, click chemistry describes the chemistry for making carbon-heteroatom-carbon bonds in benign solvents, especially in water, and having a plethora of chemical and biological applications. This has played an important role in early detection of diseases, real-time monitoring of drug delivery and investigating the biomolecular functions in vivo. This review aims at highlighting the research advancements in click chemistry published in the patent literature and categorizing the patents according to the technological progress. An extensive search was carried out to collect and analyze the patent information claiming the use of click chemistry in biotechnology, especially for diagnosis. The study further concentrates on licensing of the click chemistry patents and defining the recent breakthroughs. Different databases like Espacenet, ISI Web of Science, Patbase and Thomson Innovation are used to compile the relevant literature. In recent years, considerable development in the click concept has encouraged researchers in using click reactions in almost every branch of industry that uses chemistry. Click chemistry for chemical ligation has been immensely explored in the field of biotechnology especially for detection, diagnosis and therapeutics.

Ionospheric chemistry. [minor neutrals and ionized constituents of thermosphere

NASA Technical Reports Server (NTRS)

Torr, D. G.

1979-01-01

This report deals primarily with progress in the chemistry of minor neutrals and ionized constituents of the thermosphere. Significant progress was made over the last few years in quantitative studies of many chemical processes. This success was primarily due to the advent of multiparameter multisatellite programs which permitted accurate simultaneous measurements to be made of many important parameters. In many cases studies of chemical reactions were made with laboratory-like precision. Rate coefficients have been derived as functions of temperature for a number of important reactions. New information has been acquired on nearly every major process which occurs in the thermosphere, including the recombination rates of all major molecular ions, charge transfer reactions, ion atom interchange reactions, and reactions of neutral and ionized metastable atoms and molecules.

Secondary ion mass spectrometry and Raman spectroscopy for tissue engineering applications

PubMed Central

Ilin, Yelena; Kraft, Mary L.

2014-01-01

Identifying the matrix properties that permit directing stem cell fate is critical for expanding desired cell lineages ex vivo for disease treatment. Such efforts require knowledge of matrix surface chemistry and the cell responses they elicit. Recent progress in analyzing biomaterial composition and identifying cell phenotype with two label-free chemical imaging techniques, TOF-SIMS and Raman spectroscopy are presented. TOF-SIMS is becoming indispensable for the surface characterization of biomaterial scaffolds. Developments in TOF-SIMS data analysis enable correlating surface chemistry with biological response. Advances in the interpretation of Raman spectra permit identifying the fate decisions of individual, living cells with location specificity. Here we highlight this progress and discuss further improvements that would facilitate efforts to develop artificial scaffolds for tissue regeneration. PMID:25462628

Development and analysis of an instrument to assess student understanding of GOB chemistry knowledge relevant to clinical nursing practice.

PubMed

Brown, Corina E; Hyslop, Richard M; Barbera, Jack

2015-01-01

The General, Organic, and Biological Chemistry Knowledge Assessment (GOB-CKA) is a multiple-choice instrument designed to assess students' understanding of the chemistry topics deemed important to clinical nursing practice. This manuscript describes the development process of the individual items along with a psychometric evaluation of the final version of the items and instrument. In developing items for the GOB-CKA, essential topics were identified through a series of expert interviews (with practicing nurses, nurse educators, and GOB chemistry instructors) and confirmed through a national survey. Individual items were tested in qualitative studies with students from the target population for clarity and wording. Data from pilot and beta studies were used to evaluate each item and narrow the total item count to 45. A psychometric analysis performed on data from the 45-item final version was used to provide evidence of validity and reliability. The final version of the instrument has a Cronbach's alpha value of 0.76. Feedback from an expert panel provided evidence of face and content validity. Convergent validity was estimated by comparing the results from the GOB-CKA with the General-Organic-Biochemistry Exam (Form 2007) of the American Chemical Society. Instructors who wish to use the GOB-CKA for teaching and research may contact the corresponding author for a copy of the instrument. © 2014 Wiley Periodicals, Inc.

Superconducting selenides intercalated with organic molecules: synthesis, crystal structure, electric and magnetic properties, superconducting properties, and phase separation in iron based-chalcogenides and hybrid organic-inorganic superconductors

NASA Astrophysics Data System (ADS)

Krzton-Maziopa, Anna; Pesko, Edyta; Puzniak, Roman

2018-06-01

Layered iron-based superconducting chalcogenides intercalated with molecular species are the subject of intensive studies, especially in the field of solid state chemistry and condensed matter physics, because of their intriguing chemistry and tunable electric and magnetic properties. Considerable progress in the research, revealing superconducting inorganic–organic hybrid materials with transition temperatures to superconducting state, T c, up to 46 K, has been brought in recent years. These novel materials are synthesized by low-temperature intercalation of molecular species, such as solvates of alkali metals and nitrogen-containing donor compounds, into layered FeSe-type structure. Both the chemical nature as well as orientation of organic molecules between the layers of inorganic host, play an important role in structural modifications and may be used for fine tuning of superconducting properties. Furthermore, a variety of donor species compatible with alkali metals, as well as the possibility of doping also in the host structure (either on Fe or Se sites), makes this system quite flexible and gives a vast array of new materials with tunable electric and magnetic properties. In this review, the main aspects of intercalation chemistry are discussed with a particular attention paid to the influence of the unique nature of intercalating species on the crystal structure and physical properties of the hybrid inorganic–organic materials. To get a full picture of these materials, a comprehensive description of the most effective chemical and electrochemical methods, utilized for synthesis of intercalated species, with critical evaluation of their strong and weak points, related to feasibility of synthesis, phase purity, crystal size and morphology of final products, is included as well.

Ethics in Science: The Unique Consequences of Chemistry.

PubMed

Kovac, Jeffrey

2015-01-01

This article discusses the ethical issues unique to the science and practice of chemistry. These issues arise from chemistry's position in the middle between the theoretical and the practical, a science concerned with molecules that are of the right size to directly affect human life. Many of the issues are raised by the central activity of chemistry--synthesis. Chemists make thousands of new substances each year. Many are beneficial, but others are threats. Since the development of the chemical industry in the nineteenth century, chemistry has contributed to the deterioration of the environment but has also helped to reduce pollution. Finally, we discuss the role of codes of ethics and whether the current codes of conduct for chemists are adequate for the challenges of today's world.

Supplemental instruction in chemistry

NASA Astrophysics Data System (ADS)

Lundeberg, Mary A.

This study was designed to measure some effects of supplemental instruction in chemistry. Supplemental instruction is a peer-led cooperative learning program that encourages students to develop conceptual understanding by articulating both understandings and misconceptions in a think-aloud fashion. Supplemental instruction was offered three hours weekly outside of class and lab time for students in four classes of General Organic and Biological Chemistry. Over a two-year period 108 students volunteered to participate in this program; 45 students did not participate. As measured by final grades in chemistry and responses to a questionnaire, supplemental instruction was effective in increasing students' achievement in chemistry. Further research is needed to determine the in-depth effects of supplemental instruction on students' learning, problem solving, and self-esteem.

Snow deposition, melt, runoff, and chemistry in a small alpine watershed, Emerald Lake Basin, Sequoia National Park. Final report, 1 July 1984-31 March 1987

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dozier, J.; Melack, J.M.; Marks, D.

1987-03-01

The report describes the first two years of an investigation of the snow chemistry and hydrology of the Emerald Lake Watershed in Sequoia National Park. The investigation examined the impact of acid deposition on high-elevation ecosystems of the Sierra Nevada. The following aspects of snow deposition and melt were studied: energy inputs; pattern of snow deposition and ablation; snowpack, meltwater and runoff chemistry; stream hydrology during the melt period.

34 CFR Appendix A to Part 104 - Analysis of Final Regulation

Code of Federal Regulations, 2010 CFR

2010-07-01

... college to offer biology, the second physics, and the third chemistry to all students at the three... lab accessible, another its physics lab, and a third its chemistry lab, and under which mobility... provide health, welfare, or other social services may also comply with § 104.22 by delivering services at...

Fostering the Development of Chemistry Teacher Candidates: A Bioecological Approach

ERIC Educational Resources Information Center

Lewthwaite, Brian; Wiebe, Rick

2012-01-01

This ongoing research inquiry investigates through the analysis of teacher candidate experiences the factors influencing two groups of chemistry teacher candidates' development during their extended practica in their second and final year of an after-degree bachelor of education at a university in central Canada. The tenets of Bronfenbrenner's…

Towards Treating Chemistry Teacher Candidates as Human

ERIC Educational Resources Information Center

Lewthwaite, Brian Ellis

2008-01-01

This research inquiry investigates the factors influencing chemistry teacher candidates' development during their extended practica in the second and final year of an After-Degree Bachelor of Education at a university in central Canada. A variety of data sources are used to identify the risk and protective factors impeding and contributing to the…

Evaluation of Future Blogs. Final Report

ERIC Educational Resources Information Center

Haines, Ben; Straw, Suzanne

2008-01-01

Future Blogs was developed through collaboration between the Royal Society of Chemistry and The Brightside Trust. It is an innovative e-mentoring scheme that links pupils studying chemistry with mentors from universities or industry and is based on the Bright Journals e-mentoring programme (an e-mentoring scheme targeted at 14-18 year olds…

A Multistep Synthesis Featuring Classic Carbonyl Chemistry for the Advanced Organic Chemistry Laboratory

ERIC Educational Resources Information Center

Duff, David B.; Abbe, Tyler G.; Goess, Brian C.

2012-01-01

A multistep synthesis of 5-isopropyl-1,3-cyclohexanedione is carried out from three commodity chemicals. The sequence involves an aldol condensation, Dieckmann-type annulation, ester hydrolysis, and decarboxylation. No purification is required until after the final step, at which point gravity column chromatography provides the desired product in…

Measuring the development of conceptual understanding in chemistry

NASA Astrophysics Data System (ADS)

Claesgens, Jennifer Marie

The purpose of this dissertation research is to investigate and characterize how students learn chemistry from pre-instruction to deeper understanding of the subject matter in their general chemistry coursework. Based on preliminary work, I believe that students have a general pathway of learning across the "big ideas," or concepts, in chemistry that can be characterized over the course of instruction. My hypothesis is that as students learn chemistry they build from experience and logical reasoning then relate chemistry specific ideas in a pair-wise fashion before making more complete multi-relational links for deeper understanding of the subject matter. This proposed progression of student learning, which starts at Notions, moves to Recognition, and then to Formulation, is described in the ChemQuery Perspectives framework. My research continues the development of ChemQuery, an NSF-funded assessment system that uses a framework of the key ideas in the discipline and criterion-referenced analysis using item response theory (IRT) to map student progress. Specifially, this research investigates the potential for using criterion-referenced analysis to describe and measure how students learn chemistry followed by more detailed task analysis of patterns in student responses found in the data. My research question asks: does IRT work to describe and measure how students learn chemistry and if so, what is discovered about how students learn? Although my findings seem to neither entirely support nor entirely refute the pathway of student understanding proposed in the ChemQuery Perspectives framework. My research does provide an indication of trouble spots. For example, it seems like the pathway from Notions to Recognition is holding but there are difficulties around the transition from Recognition to Formulation that cannot be resolved with this data. Nevertheless, this research has produced the following, which has contributed to the development of the ChemQuery assessment system, (a) 13 new change items with good fits, 3 new change items that need further study, (b) a refined scoring guide and (c) a set of item exemplars that can then be developed further into a computer-adapted model so that more data can be captured.

Selected clinical chemistry analytes correlate with the pathogenesis of inclusion body hepatitis experimentally induced by fowl aviadenoviruses.

PubMed

Matos, Miguel; Grafl, Beatrice; Liebhart, Dieter; Schwendenwein, Ilse; Hess, Michael

2016-10-01

In the present study, clinical chemistry was applied to assess the pathogenesis and progression of experimentally induced inclusion body hepatitis (IBH). For this, five fowl aviadenovirus (FAdV) strains from recent IBH field outbreaks were used to orally inoculate different groups of day-old specific pathogen-free chickens, which were weighed, sampled and examined during necropsy by sequential killing. Mortalities of 50% and 30% were recorded in two groups between 6 and 9 days post-infection (dpi), along with a decreased weight of 23% and 20%, respectively, compared to the control group. Macroscopical changes were seen in the liver and kidney between 6 and 10 dpi, with no lesions being observed in the other organs. Histological lesions were observed in the liver and pancreas during the same period. Plasma was collected from killed birds of each group at each time point and the following clinical chemistry analytes were investigated: aspartate aminotransferase (AST), glutamate dehydrogenase (GLDH), bile acids, total protein, albumin, uric acid and lipase. Plasma protein profile, AST and GLDH, together with bile acids values paralleled the macroscopical and histopathological lesions in the liver, while plasma lipase activity levels coincided with lesions observed in pancreas. In agreement with the histology and clinical chemistry, viral load in the target organs, liver and pancreas, was highest at 7 dpi. Thus, clinical chemistry was found to be a valuable tool in evaluating and monitoring the progression of IBH in experimentally infected birds, providing a deeper knowledge of the underlying pathophysiological mechanisms of a FAdV infection in chickens.

Recovery from chronic and snowmelt acidification: Long-term trends in stream and soil water chemistry at the Hubbard Brook Experimental Forest, New Hampshire, USA

Treesearch

Colin B. Fuss; Charles T. Driscoll; John L. Campbell

2015-01-01

Atmospheric acid deposition of sulfate and nitrate has declined markedly in the northeastern United States due to emissions controls. We investigated long-term trends in soil water (1984–2011) and stream water (1982–2011) chemistry along an elevation gradient of a forested watershed to evaluate the progress of recovery of drainage waters from acidic deposition at the...

Gas-Cooled Reactor Programs annual progress report for period ending December 31, 1973. [HTGR fuel reprocessing, fuel fabrication, fuel irradiation, core materials, and fission product distribution; GCFR fuel irradiation and steam generator modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kasten, P.R.; Coobs, J.H.; Lotts, A.L.

1976-04-01

Progress is summarized in studies relating to HTGR fuel reprocessing, refabrication, and recycle; HTGR fuel materials development and performance testing; HTGR PCRV development; HTGR materials investigations; HTGR fuel chemistry; HTGR safety studies; and GCFR irradiation experiments and steam generator modeling.

Characterizing the Development of Students' Understandings regarding the Second Law of Thermodynamics: Using Learning Progressions to Illuminate Thinking in High School Chemistry

ERIC Educational Resources Information Center

Cunningham, Kevin D.

2011-01-01

As demonstrated by their emphasis in the new, national, science education standards, learning progressions (LPs) have become a valuable means of informing teaching and learning. LPs serve this role by isolating the key components of central skills and understandings, and by describing how those abilities and concepts tend to develop over time…

Chemistry and materials science progress report, FY 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-07-01

Research is reported in the areas of surface science, fundamentals of the physics and processing of metals, energetic materials, transactinide materials and properties and other indirectly related areas of weapons research.

ASRC Report, 1984-85

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1985-11-01

Research progress is reviewed for: energy and climate; aerobiology and water-air exchange; atmospheric electricity; aerosol science and air pollution; atmospheric chemistry, and cloud physics. A staff directory, bibliography, and awards listing are included. (PSB)

Comparison of multiple atmospheric chemistry schemes in C-IFS

NASA Astrophysics Data System (ADS)

Flemming, Johannes; Huijnen, Vincent; Arteta, Joaquim; Stein, Olaf; Inness, Antje; Josse, Beatrice; Schultz, Martin; Peuch, Vincent-Henri

2013-04-01

As part of the MACCII -project (EU-FP7) ECMWF's integrated forecast system (IFS) is being extended by modules for chemistry, deposition and emission of reactive gases. This integration of the chemistry complements the integration of aerosol processes in IFS (Composition-IFS). C-IFS provides global forecasts and analysis of atmospheric composition. Its main motivation is to utilize the IFS for the assimilation of satellite observation of atmospheric composition. Furthermore, the integration of chemistry packages directly into IFS will achieve better consistency in terms of the treatment of physical processes and has the potential for simulating interactions between atmospheric composition and meteorology. Atmospheric chemistry in C-IFS can be represented by the modified CB05 scheme as implemented in the TM5 model and the RACMOBUS scheme as implemented in the MOCAGE model. An implementation of the scheme of the MOZART 3.5 model is ongoing. We will present the latest progress in the development and application of C-IFS. We will focus on the comparison of the different chemistry schemes in an otherwise identical C-IFS model setup (emissions, meteorology) as well as in their original Chemistry and Transport Model setup.

MELCOR/CONTAIN LMR Implementation Report - FY16 Progress.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Louie, David; Humphries, Larry L.

2016-11-01

This report describes the progress of the CONTAIN - LMR sodium physics and chemistry models to be implemented in MELCOR 2.1. In the past three years , the implementation included the addition of sodium equations of state and sodium properties from two different sources. The first source is based on the previous work done by Idaho National Laboratory by modifying MELCOR to include liquid lithium equation of state as a working fluid to model the nuclear fusion safety research. The second source uses properties generated for the SIMMER code. The implemented modeling has been tested and results are reported inmore » this document. In addition, the CONTAIN - LMR code was derived from an early version of the CONTAIN code, and many physical models that were developed since this early version of CONTAIN are not available in this early code version. Therefore, CONTAIN 2 has been updated with the sodium models in CONTAIN - LMR as CONTAIN2 - LMR, which may be used to provide code-to-code comparison with CONTAIN - LMR and MELCOR when the sodium chemistry models from CONTAIN - LMR have been completed. Both the spray fire and pool fire chemistry routines from CONTAIN - LMR have been integrated into MELCOR 2.1, and debugging and testing are in progress. Because MELCOR only models the equation of state for liquid and gas phases of the coolant, a modeling gap still exists when dealing with experiments or accident conditions that take place when the ambient temperature is below the freezing point of sodium. An alternative method is under investigation to overcome this gap . We are no longer working on the separate branch from the main branch of MELCOR 2.1 since the major modeling of MELCOR 2.1 has been completed. At the current stage, the newly implemented sodium chemistry models will be a part of the main MELCOR release version (MELCOR 2.2). This report will discuss the accomplishments and issues relating to the implementation. Also, we will report on the planned completion of all remaining tasks in the upcoming FY2017, including the atmospheric chemistry model and sodium - concrete interaction model implementation .« less

Farewell Year 12: Chemistry at Nagle College

ERIC Educational Resources Information Center

Awad, Maro; Azar, Stefanie; Vieiro, Bianca; van Rooy, Wilhelmina

2012-01-01

With one week to go, Year 12 chemistry made their final practical an event to be remembered. We decided to take that infamous Periodic Table to the next level, transforming it into an edible table! Armed with 114 biscuits, multiple tubs filled with coloured icing, plastic knives, and gloves and "Professional" piping bags, we converted the science…

Advanced Chemical Modeling for Turbulent Combustion Simulations

DTIC Science & Technology

2012-05-03

premixed combustion. The chemistry work proposes a method for defining jet fuel surrogates, describes how different sub- mechanisms can be incorporated...Chemical Modeling For Turbulent Combustion Simulations Final Report submitted by: Heinz Pitsch (PI) Stanford University Mechanical Engineering Flow Physics...predict the combustion characteristics of fuel oxidation and pollutant emissions from engines . The relevant fuel chemistry must be accurately modeled

An Evaluation of a Self-Paced Approach to Elementary Chemistry Instruction.

ERIC Educational Resources Information Center

Schaumburg, Gary F.

The objectives of this study were: (1) to compare retention rates between self-paced (SP) and classical lecture (CL) chemistry students as measured by the proportion of students who received a withdrawal or unofficial withdrawal grade; (2) as indicated by the distribution of final grades, to compare student achievement between SP and CL students;…

Chemistry Teaching for the Future: A Model for Secondary Chemistry Education for Sustainable Development

ERIC Educational Resources Information Center

Jegstad, Kirsti Marie; Sinnes, Astrid Tonette

2015-01-01

For more than 40 years, the international community has acknowledged the role education might play in environmental awareness and conservation. The last major initiative came when the United Nations General Assembly proclaimed a Decade of Education for Sustainable Development (2005-2014). In the final year of the decade, teachers still struggle to…

78 FR 20891 - Glycine From the People's Republic of China: Final Results of Antidumping Duty Administrative...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-08

... company subject to this review, Baoding Mantong Fine Chemistry Co. Ltd. (Baoding Mantong), and are... February 29, 2012: Exporter Margin PRC-wide entity (including Baoding Mantong Fine 453.79% Chemistry Co... Laboratories India Ltd. 4. Avid Organics Pvt. Ltd. 5. Chiyuen International Trading Ltd. 6. E-Heng Import and...

Enabling technologies built on a sonochemical platform: challenges and opportunities.

PubMed

Cintas, Pedro; Tagliapietra, Silvia; Caporaso, Marina; Tabasso, Silvia; Cravotto, Giancarlo

2015-07-01

Scientific and technological progress now occurs at the interface between two or more scientific and technical disciplines while chemistry is intertwined with almost all scientific domains. Complementary and synergistic effects have been found in the overlay between sonochemistry and other enabling technologies such as mechanochemistry, microwave chemistry and flow-chemistry. Although their nature and effects are intrinsically different, these techniques share the ability to significantly activate most chemical processes and peculiar phenomena. These studies offer a comprehensive overview of sonochemistry, provide a better understanding of correlated phenomena (mechanochemical effects, hot spots, etc.), and pave the way for emerging applications which unite hybrid reactors. Copyright © 2014 Elsevier B.V. All rights reserved.

Cellular uptake: lessons from supramolecular organic chemistry.

PubMed

Gasparini, Giulio; Bang, Eun-Kyoung; Montenegro, Javier; Matile, Stefan

2015-07-04

The objective of this Feature Article is to reflect on the importance of established and emerging principles of supramolecular organic chemistry to address one of the most persistent problems in life sciences. The main topic is dynamic covalent chemistry on cell surfaces, particularly disulfide exchange for thiol-mediated uptake. Examples of boronate and hydrazone exchange are added for contrast, comparison and completion. Of equal importance are the discussions of proximity effects in polyions and counterion hopping, and more recent highlights on ring tension and ion pair-π interactions. These lessons from supramolecular organic chemistry apply to cell-penetrating peptides, particularly the origin of "arginine magic" and the "pyrenebutyrate trick," and the currently emerging complementary "disulfide magic" with cell-penetrating poly(disulfide)s. They further extend to the voltage gating of neuronal potassium channels, gene transfection, and the delivery of siRNA. The collected examples illustrate that the input from conceptually innovative chemistry is essential to address the true challenges in biology beyond incremental progress and random screening.

Blinn College Final Grade Distribution Report for Spring 1994 Semester. Student Performance Report. International Research Document No. 012E.

ERIC Educational Resources Information Center

Blinn Coll., Brenham, TX.

Blinn College final course grade distributions are summarized for spring 1990 to 1994 in this four-part report. Section I presents tables of final grade distributions by campus and course in accounting; agriculture; anthropology; biology; business; chemistry; child development; communications; computer science; criminal justice; drama; emergency…

Pim-1: A Molecular Target to Modulate Cellular Resistance to Therapy in Prostate Cancer

DTIC Science & Technology

2007-10-01

submitted to the Journal of Biological Chemistry . BODY We will outline our progress through reference to the specific aims described above. The first... Chemistry (see manuscript in appendix). The goal of specific aim #2 was to define pathways through which the PIM1 kinase could activate NFkB...or with three other flavonoids , has been determined. We have also shown that quercetagetin is able to inhibit the activity of the PIM1 kinase in

High precision optical spectroscopy and quantum state selected photodissociation of ultracold 88Sr2 molecules in an optical lattice

NASA Astrophysics Data System (ADS)

McDonald, Mickey Patrick

Over the past several decades, rapid progress has been made toward the accurate characterization and control of atoms, made possible largely by the development of narrow-linewidth lasers and techniques for trapping and cooling at ultracold temperatures. Extending this progress to molecules will have exciting implications for chemistry, condensed matter physics, and precision tests of physics beyond the Standard Model. These possibilities are all consequences of the richness of molecular structure, which is governed by physics substantially different from that characterizing atomic structure. This same richness of structure, however, increases the complexity of any molecular experiment manyfold over its atomic counterpart, magnifying the difficulty of everything from trapping and cooling to the comparison of theory with experiment. This thesis describes work performed over the past six years to establish the state of the art in manipulation and quantum control of ultracold molecules. Our molecules are produced via photoassociation of ultracold strontium atoms followed by spontaneous decay to a stable ground state. We describe a thorough set of measurements characterizing the rovibrational structure of very weakly bound (and therefore very large) 88Sr2 molecules from several different perspectives, including determinations of binding energies; linear, quadratic, and higher order Zeeman shifts; transition strengths between bound states; and lifetimes of narrow subradiant states. The physical intuition gained in these experiments applies generally to weakly bound diatomic molecules, and suggests extensive applications in precision measurement and metrology. In addition, we present a detailed analysis of the thermally broadened spectroscopic lineshape of molecules in a non-magic optical lattice trap, showing how such lineshapes can be used to directly determine the temperature of atoms or molecules in situ, addressing a long-standing problem in ultracold physics. Finally, we discuss the measurement of photofragment angular distributions produced by photodissociation, leading to an exploration of quantum-state-resolved ultracold chemistry.

Changes in peat chemistry associated with permafrost thaw increase greenhouse gas production

PubMed Central

Hodgkins, Suzanne B.; Tfaily, Malak M.; McCalley, Carmody K.; Logan, Tyler A.; Crill, Patrick M.; Saleska, Scott R.; Rich, Virginia I.; Chanton, Jeffrey P.

2014-01-01

Carbon release due to permafrost thaw represents a potentially major positive climate change feedback. The magnitude of carbon loss and the proportion lost as methane (CH4) vs. carbon dioxide (CO2) depend on factors including temperature, mobilization of previously frozen carbon, hydrology, and changes in organic matter chemistry associated with environmental responses to thaw. While the first three of these effects are relatively well understood, the effect of organic matter chemistry remains largely unstudied. To address this gap, we examined the biogeochemistry of peat and dissolved organic matter (DOM) along a ∼40-y permafrost thaw progression from recently- to fully thawed sites in Stordalen Mire (68.35°N, 19.05°E), a thawing peat plateau in northern Sweden. Thaw-induced subsidence and the resulting inundation along this progression led to succession in vegetation types accompanied by an evolution in organic matter chemistry. Peat C/N ratios decreased whereas humification rates increased, and DOM shifted toward lower molecular weight compounds with lower aromaticity, lower organic oxygen content, and more abundant microbially produced compounds. Corresponding changes in decomposition along this gradient included increasing CH4 and CO2 production potentials, higher relative CH4/CO2 ratios, and a shift in CH4 production pathway from CO2 reduction to acetate cleavage. These results imply that subsidence and thermokarst-associated increases in organic matter lability cause shifts in biogeochemical processes toward faster decomposition with an increasing proportion of carbon released as CH4. This impact of permafrost thaw on organic matter chemistry could intensify the predicted climate feedbacks of increasing temperatures, permafrost carbon mobilization, and hydrologic changes. PMID:24711402

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petersen, G.

Based on recent progress in the understanding of atmospheric mercury chemistry this study makes an attempt to model the atmospheric transport, chemical transformations and the dry and wet deposition fluxes by means of a Lagrangian trajectory model with a simplified chemistry scheme and a comprehensive three dimensional Eulerian model, which is comprised of a series of modules with a more detailed description of emissions, transport, gaseous and aqueous chemistry, cloud mixing and scavenging and dry and wet deposition at different vertical levels in the entire troposphere. The Lagrangian model is used to calculate the long-range transport of mercury species frommore » the main emission areas in Central Europe to Scandinavia and the adjacent sea areas. Validation of the model has been performed by comparing calculated concentrations of mercury in air and precipitation with observed concentrations at monitoring stations in Sweden and Germany. The observations are quite well reproduced by the model despite their relatively wide geographical separation. Further evaluation of the model results would require additional measurement data for organic and inorganic gaseous mercury compounds as well as for mercury associated with particles. Further progress in understanding the atmospheric mercury cycle has emphasized the need for mesoscale capability interfaced with large-scale Eulerian models to obtain a `nested` model system. As a first step in this direction, a stand-alone version of the ADOM mercury aqueous chemistry and scavenging model has been developed. This module allows changes to the chemistry alone to be evaluated for a single grid column at different vertical levels. Effects of different aqueous redox reactions together with a range of equilibrium constants for adsorption of mercury species on soot particles are investigated by running the module.« less

Effects and Implications of Mini-Lectures on Learning in First-Semester General Chemistry

ERIC Educational Resources Information Center

Toto, Joe; Booth, Kathy

2008-01-01

This study describes the efficacy of a novel tool, mini-lecture movies, in teaching Web based general chemistry. The analysis shows a marked improvement in student learning, as evidenced by a corresponding increase in homework and final exam scores. Students with access to mini-lecture movies scored 11.2% (p = 0.016) higher than students who did…

From transistor to trapped-ion computers for quantum chemistry.

PubMed

Yung, M-H; Casanova, J; Mezzacapo, A; McClean, J; Lamata, L; Aspuru-Guzik, A; Solano, E

2014-01-07

Over the last few decades, quantum chemistry has progressed through the development of computational methods based on modern digital computers. However, these methods can hardly fulfill the exponentially-growing resource requirements when applied to large quantum systems. As pointed out by Feynman, this restriction is intrinsic to all computational models based on classical physics. Recently, the rapid advancement of trapped-ion technologies has opened new possibilities for quantum control and quantum simulations. Here, we present an efficient toolkit that exploits both the internal and motional degrees of freedom of trapped ions for solving problems in quantum chemistry, including molecular electronic structure, molecular dynamics, and vibronic coupling. We focus on applications that go beyond the capacity of classical computers, but may be realizable on state-of-the-art trapped-ion systems. These results allow us to envision a new paradigm of quantum chemistry that shifts from the current transistor to a near-future trapped-ion-based technology.

Inner-shell chemistry under high pressure

NASA Astrophysics Data System (ADS)

Miao, Maosheng; Botana, Jorge; Pravica, Michael; Sneed, Daniel; Park, Changyong

2017-05-01

Chemistry at ambient conditions has implicit boundaries rooted in the atomic shell structure: the inner-shell electrons and the unoccupied outer-shell orbitals do not contribute as the major component to chemical reactions and in chemical bonds. These general rules govern our understanding of chemical structures and reactions. We review the recent progresses in high-pressure chemistry demonstrating that the above rules can be violated under extreme conditions. Using a first principles computation method and crystal structure search algorithm, we demonstrate that stable compounds involving inner shell electrons such as CsF3, CsF5, HgF3, and HgF4 can form under high external pressure and may present exotic properties. We also discuss experimental studies that have sought to confirm these predictions. Employing our recently developed hard X-ray photochemistry methods in a diamond anvil cell, we show promising early results toward realizing inner shell chemistry experimentally.

From transistor to trapped-ion computers for quantum chemistry

PubMed Central

Yung, M.-H.; Casanova, J.; Mezzacapo, A.; McClean, J.; Lamata, L.; Aspuru-Guzik, A.; Solano, E.

2014-01-01

Over the last few decades, quantum chemistry has progressed through the development of computational methods based on modern digital computers. However, these methods can hardly fulfill the exponentially-growing resource requirements when applied to large quantum systems. As pointed out by Feynman, this restriction is intrinsic to all computational models based on classical physics. Recently, the rapid advancement of trapped-ion technologies has opened new possibilities for quantum control and quantum simulations. Here, we present an efficient toolkit that exploits both the internal and motional degrees of freedom of trapped ions for solving problems in quantum chemistry, including molecular electronic structure, molecular dynamics, and vibronic coupling. We focus on applications that go beyond the capacity of classical computers, but may be realizable on state-of-the-art trapped-ion systems. These results allow us to envision a new paradigm of quantum chemistry that shifts from the current transistor to a near-future trapped-ion-based technology. PMID:24395054

Quarterly Progress Report for the Chemical and Energy Research Section of the Chemical Technology Division: July-September 1999

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jubin, R.T.

2001-04-16

This report summarizes the major activities conducted in the Chemical and Energy Research Section of the Chemical Technology Division at Oak Ridge National Laboratory (ORNL) during the period July-September 1999. The section conducts basic and applied research and development in chemical engineering, applied chemistry, and bioprocessing, with an emphasis on energy-driven technologies and advanced chemical separations for nuclear and waste applications. The report describes the various tasks performed within ten major areas of research: Hot Cell Operations, Process Chemistry, Molten Salt Reactor Experiment (MSRE) Remediation Studies, Chemistry Research, Physical Properties Research, Biochemical Engineering, Separations and Materials Synthesis, Fluid Structures andmore » Properties, Biotechnology Research, and Molecular Studies. The name of a technical contact is included with each task described, and readers are encouraged to contact these individuals if they need additional information. Activities conducted within the area of the Cell Operations involved the testing of two continuously stirred tank reactors in series to evaluate the Savannah River-developed process of small-tank tetraphenylborate precipitation to remove cesium, strontium and transuranics from supernatant. Within the area of Process Chemistry, various topics related to solids formation in process solutions from caustic treatment of Hanford sludge were addressed. Saltcake dissolution efforts continued, including the development of a predictive algorithm. New initiatives for the section included modeling activities centered on detection of hydrogen in {sup 233}U storage wells and wax formation in petroleum mixtures, as well as support for the Spallation Neutron Source (investigation of transmutation products formed during operation). Other activities involved in situ grouting and evaluation of options for use (i.e., as castable shapes) of depleted uranium. In a continuation of activities of the preceding quarter, MSRE Remediation Studies focused on recovery of {sup 233}U and its conversion to a stable oxide and radiolysis experiments to permit remediation of MSRE fuel salt. Investigation of options for final disposition of the {sup 233}U inventory represents a new initiative within this area. In the area of Chemistry Research, activities included studies relative to molecular imprinting for use in areas such as selective sorption, chemical sensing, and catalysis, as well as spectroscopic investigation into the fundamental interaction between ionic solvents and solutes in both low- and high-temperature ionic liquids.« less

Instructional Model and Thinking Skill in Chemistry Class

NASA Astrophysics Data System (ADS)

Langkudi, H. H.

2018-02-01

Chemistry course are considered a difficult lesson for students as evidenced by low learning outcomes on daily tests, mid-semester tests as well as final semester tests. This research intended to investigate the effect of instructional model, thinking skill and the interaction of these variables on students’ achievement in chemistry. Experimental method was applying used 2 x 2 factorial design. The results showed that the use of instructional model with thinking skill influences student’s learning outcomes, so that the chemistry teacher is recommended to pay attention to the learning model, and adjusted to the student’s skill thinking on the chemistry material being taught. The conclusion of this research is that discovery model is suitable for students who have formal thinking skill and conventional model is fit for the students that have concrete thinking skill.

Photoredox Catalysis for the Generation of Carbon Centered Radicals.

PubMed

Goddard, Jean-Philippe; Ollivier, Cyril; Fensterbank, Louis

2016-09-20

Radical chemistry has witnessed over the last decades important advances that have positioned it as a methodology of choice in synthetic chemistry. A number of great attributes such as specific reactivities, the knowledge of the kinetics of most elementary processes, the functional group tolerance, and the possibility to operate cascade sequences are clearly responsible for this craze. Nevertheless, at the end of the last century, radical chemistry appeared plagued by several hurdles to overcome such as the use of environmentally problematic mediators or the impossibility of scale up. While the concept of photocatalysis was firmly established in the coordination chemistry community, its diffusion in organic synthetic chemistry remained sporadic for decades until the end of the 2000s with the breakthrough merging of organocatalysis and photocatalysis by the MacMillan group and contemporary reports by the groups of Yoon and Stephenson. Since then, photoredox catalysis has enjoyed particularly active and intense developments. It is now the topic of a still increasing number of publications featuring various applications from asymmetric synthesis, total synthesis of natural products, and polymerization to process (flow) chemistry. In this Account, we survey our own efforts in this domain, focusing on the elaboration of new photocatalytic pathways that could lead to the efficient generation of C-centered functionalized alkyl and aryl radicals. Both reductive and oxidative manifolds are accessible through photoredox catalysis, which has guided us along these lines in our projects. Thus, we studied the photocatalytic reduction of onium salts such as sulfoniums and iodoniums for the production of the elusive aryl radical intermediates. Progressing to more relevant chemistry for synthesis, we examined the cleavage of C-O and the C-Br bonds for the generation of alkyl C-centered radicals. Activated epoxides could serve as valuable substrates of a photocatalyzed variant of the Nugent-RajanBabu-Gansäuer homolytic cleavage of epoxides. Using imidazole based carbamates, we could also devise the first photocatalyzed Barton-McCombie deoxygenation reaction. Finally, bromophenylacetate can be reduced using the [Au2(μ-dppm)2]Cl2 photocatalyst under UVA or visible-light. This was used for the initiation of the controlled atom transfer radical polymerization of methacrylates and acrylates in solution or laminate. Our next endeavors concerned the photocatalyzed oxidation of stabilized carbanions such as enolates of 1,3-dicarbonyl substrates, trifluoroborates, and more extensively bis-catecholato silicates. Because of their low oxidation potentials, the later have proved to be exquisite sources of radical entities, which can be engaged in diverse intermolecular reactions such as vinylation, alkynylation, and conjugate additions. The bis-catecholato silicates were also shown to behave as excellent partners of dual photoredox-nickel catalysis leading in an expeditious manner to libraries of cross coupling products.

Progressive enrichment of arc magmas caused by the subduction of seamounts under Nishinoshima volcano, Izu-Bonin Arc, Japan

NASA Astrophysics Data System (ADS)

Sano, Takashi; Shirao, Motomaro; Tani, Kenichiro; Tsutsumi, Yukiyasu; Kiyokawa, Shoichi; Fujii, Toshitsugu

2016-06-01

The chemical composition of intraplate seamounts is distinct from normal seafloor material, meaning that the subduction of seamounts at a convergent margin can cause a change in the chemistry of the mantle wedge and associated arc magmas. Nishinoshima, a volcanic island in the Izu-Bonin Arc of Japan, has been erupting continuously over the past 2 years, providing an ideal opportunity to examine the effect of seamount subduction on the chemistry of arc magmas. Our research is based on the whole-rock geochemistry and the chemistry of minerals within lavas and air-fall scoria from Nishinoshima that were erupted before 1702, in 1973-1974, and in 2014. The mineral phases within the analyzed samples crystallized under hydrous conditions (H2O = 3-4 wt.%) at temperatures of 970 °C-990 °C in a shallow (3-6 km depth) magma chamber. Trace element data indicate that the recently erupted Nishinoshima volcanics are much less depleted in the high field strength elements (Nb, Ta, Zr, Hf) than other volcanics within the Izu-Bonin Arc. In addition, the level of enrichment in the Nishinoshima magmas has increased in recent years, probably due to the addition of material from HIMU-enriched (i.e., high Nb/Zr and Ta/Hf) seamounts on the Pacific Plate, which is being subducted westwards beneath the Philippine Sea Plate. This suggests that the chemistry of scoria from Nishinoshima volcano records the progressive addition of components derived from subducted seamounts.

UT/LS chemistry and transport

DOT National Transportation Integrated Search

2008-01-25

This SSWP summarizes important results in key areas since the last major aircraft impacts assessment [IPCC 1999]. Significant progress has been made in the areas of: Measurements of emissions of chemi-ions, NOx, and trace organic species from aircraf...

High pressure jet flame numerical analysis of CO emissions by means of the flamelet generated manifolds technique

NASA Astrophysics Data System (ADS)

Donini, A.; Martin, S. M.; Bastiaans, R. J. M.; van Oijen, J. A.; de Goey, L. P. H.

2013-10-01

In the present paper a computational analysis of a high pressure confined premixed turbulent methane/air jet flames is presented. In this scope, chemistry is reduced by the use of the Flamelet Generated Manifold method [1] and the fluid flow is modeled in an LES and RANS context. The reaction evolution is described by the reaction progress variable, the heat loss is described by the enthalpy and the turbulence effect on the reaction is represented by the progress variable variance. The interaction between chemistry and turbulence is considered through a presumed probability density function (PDF) approach. The use of FGM as a combustion model shows that combustion features at gas turbine conditions can be satisfactorily reproduced with a reasonable computational effort. Furthermore, the present analysis indicates that the physical and chemical processes controlling carbon monoxide (CO) emissions can be captured only by means of unsteady simulations.

Composition and chemistry of Titan's thermosphere and ionosphere.

PubMed

Vuitton, V; Yelle, R V; Lavvas, P

2009-02-28

Titan has long been known to harbour the richest atmospheric chemistry in the Solar System. Until recently, it had been believed that complex hydrocarbons and nitriles were produced through neutral chemistry that would eventually lead to the formation of micrometre sized organic aerosols. However, recent measurements by the Cassini spacecraft are drastically changing our understanding of Titan's chemistry. The Ion and Neutral Mass Spectrometer (INMS) and the Cassini Plasma Spectrometer (CAPS) revealed an extraordinary complex ionospheric composition. INMS detected roughly 50 positive ions with m/z<100 and a density higher than 0.1cm-3. CAPS provided evidence for heavy (up to 350amu) positively and negatively charged (up to 4000amu) ions. These observations all indicate that Titan's ionospheric chemistry is incredibly complex and that molecular growth starts in the upper atmosphere rather than at lower altitude. Here, we review the recent progress made on ionospheric chemistry. The presence of heavy neutrals in the upper atmosphere has been inferred as a direct consequence of the presence of complex positive ions. Benzene (C6H6) is created by ion chemistry at high altitudes and its main photolysis product, the phenyl radical (C6H5), is at the origin of the formation of aromatic species at lower altitude.

Spectroscopic Studies of Pre-Biotic Carbon Chemistry

NASA Technical Reports Server (NTRS)

Blake, Geoffrey A.

2002-01-01

As described in the original proposal and in our progress reports, research in the Blake group supported by the Exobiology program seeks to understand the pre-biotic chemistry of carbon along with that of other first- and second-row elements from the earliest stages of star formation through the development of planetary systems. The major tool used is spectroscopy, and the program has observational, laboratory, and theoretical components. The observational and theoretical programs are concerned primarily with a quantitative assessment of the chemical budgets of the biogenic elements in star-forming molecular cloud cores, while the laboratory work is focused on the complex species that characterize the prebiotic chemistry of carbon. We outline below our results over the past two years acquired, in part, with Exobiology support.

Chemistry in protoplanetary disks

NASA Astrophysics Data System (ADS)

Semenov, D. A.

2012-01-01

In this lecture I discuss recent progress in the understanding of the chemical evolution of protoplanetary disks that resemble our Solar system during the first ten million years. At the verge of planet formation, strong variations of temperature, density, and radiation intensities in these disks lead to a layered chemical structure. In hot, dilute and heavily irradiated atmosphere only simple radicals, atoms, and atomic ions can survive, formed and destroyed by gas-phase processes. Beneath the atmosphere a partly UV-shielded, warm molecular layer is located, where high-energy radiation drives rich chemistry, both in the gas phase and on dust surfaces. In a cold, dense, dark disk midplane many molecules are frozen out, forming thick icy mantles where surface chemistry is active and where complex (organic) species are synthesized.

Chemical Frustration. A Design Principle for the Discovery of New Complex Alloy and Intermetallic Phases, Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fredrickson, Daniel C

2015-06-23

Final technical report for "Chemical Frustration: A Design Principle for the Discovery of New Complex Alloy and Intermetallic Phases" funded by the Office of Science through the Materials Chemistry Program of the Office of Basic Energy Sciences.

Discovery of novel anti-HIV agents via Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click chemistry-based approach.

PubMed

Gao, Ping; Sun, Lin; Zhou, Junsu; Li, Xiao; Zhan, Peng; Liu, Xinyong

2016-09-01

In recent years, a variety of new synthetic methodologies and concepts have been proposed in the search for new pharmaceutical lead structures and optimization. Notably, the Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click chemistry approach has drawn great attention and has become a powerful tool for the generation of privileged medicinal skeletons in the discovery of anti-HIV agents. This is due to the high degree of reliability, complete specificity (chemoselectivity and regioselectivity), mild conditions, and the biocompatibility of the reactants. Herein, the authors describe the progress thus far on the discovery of novel anti-HIV agents via the CuAAC click chemistry-based approach. CuAAC click chemistry is a proven protocol for synthesizing triazole products which could serve as basic pharmacophores, act as replacements of traditional scaffold or substituent modification, be a linker of dual-target or dual-site inhibitors and more for the discovery of novel anti-HIV agents. What's more, it also provides convenience and feasibility for dynamic combinatorial chemistry and in situ screening. It is envisioned that click chemistry will draw more attention and make more contributions in anti-HIV drug discovery in the future.

Chemical Approaches for Structure and Function of RNA in Postgenomic Era

PubMed Central

Ro-Choi, Tae Suk; Choi, Yong Chun

2012-01-01

In the study of cellular RNA chemistry, a major thrust of research focused upon sequence determinations for decades. Structures of snRNAs (4.5S RNA I (Alu), U1, U2, U3, U4, U5, and U6) were determined at Baylor College of Medicine, Houston, Tex, in an earlier time of pregenomic era. They show novel modifications including base methylation, sugar methylation, 5′-cap structures (types 0–III) and sequence heterogeneity. This work offered an exciting problem of posttranscriptional modification and underwent numerous significant advances through technological revolutions during pregenomic, genomic, and postgenomic eras. Presently, snRNA research is making progresses involved in enzymology of snRNA modifications, molecular evolution, mechanism of spliceosome assembly, chemical mechanism of intron removal, high-order structure of snRNA in spliceosome, and pathology of splicing. These works are destined to reach final pathway of work “Function and Structure of Spliceosome” in addition to exciting new exploitation of other noncoding RNAs in all aspects of regulatory functions. PMID:22347623

Redox-responsive theranostic nanoplatforms based on inorganic nanomaterials.

PubMed

Han, Lu; Zhang, Xiao-Yong; Wang, Yu-Long; Li, Xi; Yang, Xiao-Hong; Huang, Min; Hu, Kun; Li, Lu-Hai; Wei, Yen

2017-08-10

Spurred on by advances in materials chemistry and nanotechnology, scientists have developed many novel nanopreparations for cancer diagnosis and therapy. To treat complex malignant tumors effectively, multifunctional nanomedicines with targeting ability, imaging properties and controlled drug release behavior should be designed and exploited. The therapeutic efficiency of loaded drugs can be dramatically improved using redox-responsive nanoplatforms which can sense the differences in the redox status of tumor tissues and healthy ones. Redox-sensitive nanocarriers can be constructed from both organic and inorganic nanomaterials; however, at present, drug delivery nanovectors progressively lean towards inorganic nanomaterials because of their facile synthesis/modification and their unique physicochemical properties. In this review, we focus specifically on the preparation and application of redox-sensitive nanosystems based on mesoporous silica nanoparticles (MSNs), carbon nanomaterials, magnetic nanoparticles, gold nanomaterials and other inorganic nanomaterials. We discuss relevant examples of redox-sensitive nanosystems in each category. Finally, we discuss current challenges and future strategies from the aspect of material design and practical application. Copyright © 2017 Elsevier B.V. All rights reserved.

Recent Advances in Ultrathin Two-Dimensional Nanomaterials.

PubMed

Tan, Chaoliang; Cao, Xiehong; Wu, Xue-Jun; He, Qiyuan; Yang, Jian; Zhang, Xiao; Chen, Junze; Zhao, Wei; Han, Shikui; Nam, Gwang-Hyeon; Sindoro, Melinda; Zhang, Hua

2017-05-10

Since the discovery of mechanically exfoliated graphene in 2004, research on ultrathin two-dimensional (2D) nanomaterials has grown exponentially in the fields of condensed matter physics, material science, chemistry, and nanotechnology. Highlighting their compelling physical, chemical, electronic, and optical properties, as well as their various potential applications, in this Review, we summarize the state-of-art progress on the ultrathin 2D nanomaterials with a particular emphasis on their recent advances. First, we introduce the unique advances on ultrathin 2D nanomaterials, followed by the description of their composition and crystal structures. The assortments of their synthetic methods are then summarized, including insights on their advantages and limitations, alongside some recommendations on suitable characterization techniques. We also discuss in detail the utilization of these ultrathin 2D nanomaterials for wide ranges of potential applications among the electronics/optoelectronics, electrocatalysis, batteries, supercapacitors, solar cells, photocatalysis, and sensing platforms. Finally, the challenges and outlooks in this promising field are featured on the basis of its current development.

Microfluidic strategies for design and assembly of microfibers and nanofibers with tissue engineering and regenerative medicine applications.

PubMed

Daniele, Michael A; Boyd, Darryl A; Adams, André A; Ligler, Frances S

2015-01-07

Fiber-based materials provide critical capabilities for biomedical applications. Microfluidic fiber fabrication has recently emerged as a very promising route to the synthesis of polymeric fibers at the micro and nanoscale, providing fine control over fiber shape, size, chemical anisotropy, and biological activity. This Progress Report summarizes advanced microfluidic methods for the fabrication of both microscale and nanoscale fibers and illustrates how different methods are enabling new biomedical applications. Microfluidic fabrication methods and resultant materials are explained from the perspective of their microfluidic device principles, including co-flow, cross-flow, and flow-shaping designs. It is then detailed how the microchannel design and flow parameters influence the variety of synthesis chemistries that can be utilized. Finally, the integration of biomaterials and microfluidic strategies is discussed to manufacture unique fiber-based systems, including cell scaffolds, cell encapsulation, and woven tissue matrices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Three-dimensional nano-biointerface as a new platform for guiding cell fate.

PubMed

Liu, Xueli; Wang, Shutao

2014-04-21

Three-dimensional nano-biointerface has been emerging as an important topic for chemistry, nanotechnology, and life sciences in recent years. Understanding the exchanges of materials, signals, and energy at biological interfaces has inspired and helped the serial design of three-dimensional nano-biointerfaces. The intimate interactions between cells and nanostructures bring many novel properties, making three-dimensional nano-biointerfaces a powerful platform to guide cell fate in a controllable and accurate way. These advantages and capabilities endow three-dimensional nano-biointerfaces with an indispensable role in developing advanced biological science and technology. This tutorial review is mainly focused on the recent progress of three-dimensional nano-biointerfaces and highlights the new explorations and unique phenomena of three-dimensional nano-biointerfaces for cell-related fundamental studies and biomedical applications. Some basic bio-inspired principles for the design and creation of three-dimensional nano-biointerfaces are also delivered in this review. Current and further challenges of three-dimensional nano-biointerfaces are finally addressed and proposed.

An Outlook on Lithium Ion Battery Technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manthiram, Arumugam

Lithium ion batteries as a power source are dominating in portable electronics, penetrating the electric vehicle market, and on the verge of entering the utility market for grid-energy storage. Depending on the application, trade-offs among the various performance parameters—energy, power, cycle life, cost, safety, and environmental impact—are often needed, which are linked to severe materials chemistry challenges. The current lithium ion battery technology is based on insertion-reaction electrodes and organic liquid electrolytes. With an aim to increase the energy density or optimize the other performance parameters, new electrode materials based on both insertion reaction and dominantly conversion reaction along withmore » solid electrolytes and lithium metal anode are being intensively pursued. In conclusion, this article presents an outlook on lithium ion technology by providing first the current status and then the progress and challenges with the ongoing approaches. In light of the formidable challenges with some of the approaches, the article finally points out practically viable near-term strategies.« less

Polymeric Janus Nanoparticles: Recent Advances in Synthetic Strategies, Materials Properties, and Applications.

PubMed

Fan, Xiaoshan; Yang, Jing; Loh, Xian Jun; Li, Zibiao

2018-06-13

Polymeric Janus nanoparticles with two sides of incompatible chemistry have received increasing attention due to their tunable asymmetric structure and unique material characteristics. Recently, with the rapid progress in controlled polymerization combined with novel fabrication techniques, a large array of functional polymeric Janus particles are diversified with sophisticated architecture and applications. In this review, the most recently developed strategies for controlled synthesis of polymeric Janus nanoparticles with well-defined size and complex superstructures are summarized. In addition, the pros and cons of each approach in mediating the anisotropic shapes of polymeric Janus particles as well as their asymmetric spatial distribution of chemical compositions and functionalities are discussed and compared. Finally, these newly developed structural nanoparticles with specific shapes and surface functions orientated applications in different domains are also discussed, followed by the perspectives and challenges faced in the further advancement of polymeric Janus nanoparticles as high performance materials. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Potential and challenges of zeolite chemistry in the catalytic conversion of biomass.

PubMed

Ennaert, Thijs; Van Aelst, Joost; Dijkmans, Jan; De Clercq, Rik; Schutyser, Wouter; Dusselier, Michiel; Verboekend, Danny; Sels, Bert F

2016-02-07

Increasing demand for sustainable chemicals and fuels has pushed academia and industry to search for alternative feedstocks replacing crude oil in traditional refineries. As a result, an immense academic attention has focused on the valorisation of biomass (components) and derived intermediates to generate valuable platform chemicals and fuels. Zeolite catalysis plays a distinct role in many of these biomass conversion routes. This contribution emphasizes the progress and potential in zeolite catalysed biomass conversions and relates these to concepts established in existing petrochemical processes. The application of zeolites, equipped with a variety of active sites, in Brønsted acid, Lewis acid, or multifunctional catalysed reactions is discussed and generalised to provide a comprehensive overview. In addition, the feedstock shift from crude oil to biomass involves new challenges in developing fields, like mesoporosity and pore interconnectivity of zeolites and stability of zeolites in liquid phase. Finally, the future challenges and perspectives of zeolites in the processing of biomass conversion are discussed.

Dopamine-assisted co-deposition: An emerging and promising strategy for surface modification.

PubMed

Qiu, Wen-Ze; Yang, Hao-Cheng; Xu, Zhi-Kang

2018-04-27

Mussel-inspired chemistry based on polydopamine (PDA) deposition has been developed as a facile and universal method for the surface modification of various materials. However, the inherent shortcomings of PDA coatings still impede their practical applications in the development of functional materials. In this review, we introduce the recent progress in the emerging dopamine-assisted co-deposition as a one-step strategy for functionalizing PDA-based coatings, and improving them in the aspects of deposition rate, morphology uniformity, surface wettability and chemical stability. The co-deposition mechanisms are categorized and discussed according to the interactions of dopamine or PDA with the introduced co-component. We also emphasize the influence of these interactions on the properties of the resultant PDA-based coatings. Meanwhile, we conclude the representative potential applications of those dopamine-assisted co-deposited coatings in material science, especially including separation membranes and biomaterials. Finally, some important issues and perspectives for theoretical study and applications are briefly discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Modern Aspects of Liquid Metal Engineering

NASA Astrophysics Data System (ADS)

Czerwinski, Frank

2017-02-01

Liquid metal engineering (LME) refers to a variety of physical and/or chemical treatments of molten metals aimed at influencing their solidification characteristics. Although the fundamentals have been known for decades, only recent progress in understanding solidification mechanisms has renewed an interest in opportunities this technique creates for an improvement of castings. This review covers conventional and novel concepts of LME with their application to modern manufacturing techniques based not only on liquid but also on semisolid routes. The role of external forces applied to the melt combined with grain nucleation control is explained along with laboratory- and commercial-scale equipment designed for implementation of various concepts exploring mechanical, electromagnetic, and ultrasound principles. An influence of melt treatments on quality of the final product is considered through distinguishing between internal integrity of net shape components and the alloy microstructure. Recent global developments indicate that exploring the synergy of melt chemistry and physical treatments achieved through LME allows creating the optimum conditions for nucleation and growth during solidification, positively affecting quality of castings.

An Outlook on Lithium Ion Battery Technology

DOE PAGES

Manthiram, Arumugam

2017-09-07

Lithium ion batteries as a power source are dominating in portable electronics, penetrating the electric vehicle market, and on the verge of entering the utility market for grid-energy storage. Depending on the application, trade-offs among the various performance parameters—energy, power, cycle life, cost, safety, and environmental impact—are often needed, which are linked to severe materials chemistry challenges. The current lithium ion battery technology is based on insertion-reaction electrodes and organic liquid electrolytes. With an aim to increase the energy density or optimize the other performance parameters, new electrode materials based on both insertion reaction and dominantly conversion reaction along withmore » solid electrolytes and lithium metal anode are being intensively pursued. In conclusion, this article presents an outlook on lithium ion technology by providing first the current status and then the progress and challenges with the ongoing approaches. In light of the formidable challenges with some of the approaches, the article finally points out practically viable near-term strategies.« less

An Outlook on Lithium Ion Battery Technology

PubMed Central

2017-01-01

Lithium ion batteries as a power source are dominating in portable electronics, penetrating the electric vehicle market, and on the verge of entering the utility market for grid-energy storage. Depending on the application, trade-offs among the various performance parameters—energy, power, cycle life, cost, safety, and environmental impact—are often needed, which are linked to severe materials chemistry challenges. The current lithium ion battery technology is based on insertion-reaction electrodes and organic liquid electrolytes. With an aim to increase the energy density or optimize the other performance parameters, new electrode materials based on both insertion reaction and dominantly conversion reaction along with solid electrolytes and lithium metal anode are being intensively pursued. This article presents an outlook on lithium ion technology by providing first the current status and then the progress and challenges with the ongoing approaches. In light of the formidable challenges with some of the approaches, the article finally points out practically viable near-term strategies. PMID:29104922

Microscale Syntheses, Reactions, and 1H NMR Spectroscopic Investigations of Square Planar Macrocyclic Tetraamido-N Cu(III) Complexes Relevant to Green Chemistry

ERIC Educational Resources Information Center

Uffelman, Erich S.; Doherty, Jonathan R.; Schulze, Carl; Burke, Amy L.; Bonnema, Kristen R.; Watson, Tanya T.; Lee, Daniel W., III

2004-01-01

Microscale fusions, description, and spectroscopic analysis of the reactivity of a square planar Cu(III) complex significant to green chemistry, are presented. The experiment also includes nine focal points on which pre-lab and post-lab questions are based, and the final exams reflect the students' comprehension of these and other features of…

Perceptions of Student-Teacher Relationships, Self-Efficacy, and Subject Matter Retention in a Secondary Chemistry Course

ERIC Educational Resources Information Center

Bechtel, Michael Dean

2012-01-01

This was a study of students who had completed a chemistry course taught by one instructor in a large urban high school during 2009-2010. It was conducted in two phases: Phase One assessed self-efficacy, teaching practices, and subject matter retention taken 16 months after course completion. Phase Two consisted of a multiple-choice final exam…

Multiple-Choice Exams and Guessing: Results from a One-Year Study of General Chemistry Tests Designed to Discourage Guessing

ERIC Educational Resources Information Center

Campbell, Mark L.

2015-01-01

Multiple-choice exams, while widely used, are necessarily imprecise due to the contribution of the final student score due to guessing. This past year at the United States Naval Academy the construction and grading scheme for the department-wide general chemistry multiple-choice exams were revised with the goal of decreasing the contribution of…

Chemophobia in the College Classroom: Extent, Sources, and Student Characteristics

NASA Astrophysics Data System (ADS)

Eddy, Roberta M.

2000-04-01

The purpose of this research was to provide an understanding of chemophobia (chemistry anxiety) at the college level by determining (i) the extent of chemophobia in the college classroom; (ii) the factors that contribute to college students' anxiety about learning chemistry and handling chemicals; and (iii) the characteristics of college students who have anxiety about learning chemistry and handling chemicals. A questionnaire containing the Derived Chemistry Anxiety Rating Scale (mean = 81.47, SD = 21.31, a = 0.94), the Revised Mathematics Anxiety Rating Scale (mean = 56.68, SD = 20.55, a = 0.98), and the Trait-Anxiety Scale (mean = 39, SD = 10, a = 0.90) was administered to 480 college students (435 nonmajors and 45 chemistry majors) taking an introductory chemistry course. Eight interviews were conducted. Quantitative data were analyzed by SPSS (p ?.05). Chemophobia was found to exist at an average level between a little bit and moderate. Highest anxiety was associated with chemistry evaluation; lowest anxiety with learning chemistry. Sources that contributed most to chemistry anxiety were, for learning, chemical equations; for evaluation, taking the final exam; and for handling chemicals, getting chemicals on hands. Women had significantly higher anxiety than men. Students with low chemistry experience had significantly higher anxiety than students with high chemistry experience. There were no significant main effects for type of major or math experience.

Laboratory Investigations of Stratospheric Halogen Chemistry

NASA Technical Reports Server (NTRS)

Wine, Paul H.; Nicovich, J. Michael; Stickel, Robert E.; Hynes, Anthony J.

1997-01-01

A final report for the NASA-supported project on laboratory investigations of stratospheric halogen chemistry is presented. In recent years, this project has focused on three areas of research: (1) kinetic, mechanistic, and thermochemical studies of reactions which produce weakly bound chemical species of atmospheric interest; (2) development of flash photolysis schemes for studying radical-radical reactions of stratospheric interest; and (3) photochemistry studies of interest for understanding stratospheric chemistry. The first section of this paper contains a discussion of work which has not yet been published. All subsequent chapters contain reprints of published papers that acknowledge support from this grant.

Discussion on the Development of Green Chemistry and Chemical Engineering

NASA Astrophysics Data System (ADS)

Zhang, Yunshen

2017-11-01

Chemical industry plays a vital role in the development process of national economy. However, in view of the special nature of the chemical industry, a large number of poisonous and harmful substances pose a great threat to the ecological environment and human health in the entire process of raw material acquisition, production, transportation, product manufacturing, and the final practical application. Therefore, it is a general trend to promote the development of chemistry and chemical engineering towards a greener environment. This article will focus on some basic problems occurred in the development process of green chemistry and chemical engineering.

Supramolecular chemistry-general principles and selected examples from anion recognition and metallosupramolecular chemistry.

PubMed

Albrecht, Markus

2007-12-01

This review gives an introduction into supramolecular chemistry describing in the first part general principles, focusing on terms like noncovalent interaction, molecular recognition, self-assembly, and supramolecular function. In the second part those will be illustrated by simple examples from our laboratories. Supramolecular chemistry is the science that bridges the gap between the world of molecules and nanotechnology. In supramolecular chemistry noncovalent interactions occur between molecular building blocks, which by molecular recognition and self-assembly form (functional) supramolecular entities. It is also termed the "chemistry of the noncovalent bond." Molecular recognition is based on geometrical complementarity based on the "key-and-lock" principle with nonshape-dependent effects, e.g., solvatization, being also highly influential. Self-assembly leads to the formation of well-defined aggregates. Hereby the overall structure of the target ensemble is controlled by the symmetry features of the certain building blocks. Finally, the aggregates can possess special properties or supramolecular functions, which are only found in the ensemble but not in the participating molecules. This review gives an introduction on supramolecular chemistry and illustrates the fundamental principles by recent examples from our group.

Chemistry and Materials Science progress report, FY 1994. Revision 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-01-01

Thrust areas of the weapons-supporting research include surface science, fundamentals of the physics and processing of metals, energetic materials, etc. The laboratory directed R and D include director`s initiatives, individual projects, and transactinium science studies.

Mathematics Competency for Beginning Chemistry Students Through Dimensional Analysis.

PubMed

Pursell, David P; Forlemu, Neville Y; Anagho, Leonard E

2017-01-01

Mathematics competency in nursing education and practice may be addressed by an instructional variation of the traditional dimensional analysis technique typically presented in beginning chemistry courses. The authors studied 73 beginning chemistry students using the typical dimensional analysis technique and the variation technique. Student quantitative problem-solving performance was evaluated. Students using the variation technique scored significantly better (18.3 of 20 points, p < .0001) on the final examination quantitative titration problem than those who used the typical technique (10.9 of 20 points). American Chemical Society examination scores and in-house assessment indicate that better performing beginning chemistry students were more likely to use the variation technique rather than the typical technique. The variation technique may be useful as an alternative instructional approach to enhance beginning chemistry students' mathematics competency and problem-solving ability in both education and practice. [J Nurs Educ. 2017;56(1):22-26.]. Copyright 2017, SLACK Incorporated.

An Unprecedented Revolution in Medicinal Chemistry Driven by the Progress of Biological Science.

PubMed

Chou, Kuo-Chen

2017-01-01

The eternal or ultimate goal of medicinal chemistry is to find most effective ways to treat various diseases and extend human beings' life as long as possible. Human being is a biological entity. To realize such an ultimate goal, the inputs or breakthroughs from the advances in biological science are no doubt most important that may even drive medicinal science into a revolution. In this review article, we are to address this from several different angles. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Enabling Technologies for the Future of Chemical Synthesis.

PubMed

Fitzpatrick, Daniel E; Battilocchio, Claudio; Ley, Steven V

2016-03-23

Technology is evolving at breakneck pace, changing the way we communicate, travel, find out information, and live our lives. Yet chemistry as a science has been slower to adapt to this rapidly shifting world. In this Outlook we use highlights from recent literature reports to describe how progresses in enabling technologies are altering this trend, permitting chemists to incorporate new advances into their work at all levels of the chemistry development cycle. We discuss the benefits and challenges that have arisen, impacts on academic-industry relationships, and future trends in the area of chemical synthesis.

Beyond alkyl transfer: Synthesis of main group metal (Mg, Ca, Zn) silyl and tris(oxazolinyl)borato complexes and their stoichiometric and catalytic reactions with borane Lewis acids and carbonyls

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lampland, Nicole Lynn

2015-05-09

Recently, the fundamental knowledge of main group metal chemistry has grown. This progress is crucial for the further development of main group metal compounds in silicon chemistry and catalysis and for advancing their applications as green alternatives to many rare earth and transition metal compounds. This thesis focuses on reactivity beyond the welldocumented alkyl-transfer applications for main group metals, and it highlights examples of reactions with Lewis acids and the reduction of carbonyls.

Recent Advances in the Synthesis of Morphine and Related Alkaloids

NASA Astrophysics Data System (ADS)

Chida, Noritaka

Morphine, an alkaloid isolated from the opium poppy, has been widely used as an analgesic, and has been a fascinating synthetic target of organic chemists. After the first total synthesis reported in 1952, a number of synthetic studies toward morphine have been reported, and findings obtained in such studies have greatly contributed to the progress of synthetic organic chemistry as well as medicinal chemistry. This review provides an overview of recent studies toward the total synthesis of morphine and related alkaloids. Work reported in the literature since 2004 will be reviewed.

Gender Differences in Cognitive and Noncognitive Factors Related to Achievement in Organic Chemistry

NASA Astrophysics Data System (ADS)

Turner, Ronna C.; Lindsay, Harriet A.

2003-05-01

For many college students in the sciences, organic chemistry poses a difficult challenge. Indeed, success in organic chemistry has proven pivotal in the careers of a vast number of students in a variety of science disciplines. A better understanding of the factors that contribute to achievement in this course should contribute to efforts to increase the number of students in the science disciplines. Further, an awareness of gender differences in factors associated with achievement should aid efforts to bolster the participation of women in chemistry and related disciplines. Using a correlation research design, the individual relationships between organic chemistry achievement and each of several cognitive variables and noncognitive variables were assessed. In addition, the relationships between organic chemistry achievement and combinations of these independent variables were explored. Finally, gender- and instructor-related differences in the relationships between organic chemistry achievement and the independent variables were investigated. Cognitive variables included the second-semester general chemistry grade, the ACT English, math, reading, and science-reasoning scores, and scores from a spatial visualization test. Noncognitive variables included anxiety, confidence, effectance motivation, and usefulness. The second-semester general chemistry grade was found to be the best indicator of performance in organic chemistry, while the effectiveness of other predictors varied between instructors. In addition, gender differences were found in the explanations of organic chemistry achievement variance provided by this study. In general, males exhibited stronger correlations between predictor variables and organic chemistry achievement than females.

Avian plasma chemistry analysis using diluted samples.

PubMed

Waldoch, Jennifer; Wack, Raymund; Christopher, Mary

2009-12-01

Clinical chemistry tests are essential for the diagnosis and monitoring of disease in birds. The small volume of blood that can be obtained from many avian species limits the use of routine in-house chemistry analyzers. The aim of this study was to examine the accuracy and precision of avian plasma chemistry values obtained by use of a benchtop analyzer in samples diluted with sterile water, as compared with undiluted samples. Whole blood samples were collected from 13 clinically healthy thick-billed parrots (Rhynchopsitta pachyrhyncha). The samples were placed in lithium heparin tubes and centrifuged and the plasma decanted. One aliquot was analyzed immediately using a VetScan benchtop analyzer with an avian-reptile-specific rotor that included 12 analytes. The remainder of the plasma was divided into two aliquots and stored at -80 degrees C until analysis. One of these aliquots was diluted 1:1, 1:1.5, 1:2, and 1:2.5 with sterile water to give final dilutions of 1:2, 1:2.5, 1:3, and 1:3.5, respectively. The other aliquot was pooled with the 12 other samples to create a plasma pool. The undiluted plasma pool and two final dilutions (1:2 and 1:3) of the pooled plasma were analyzed in replicate (n = 20) to determine intra- and interassay imprecision. Each dilution was analyzed using the avian-reptile rotor and the results multiplied by the appropriate dilution factor to obtain the final result. Significant differences were observed in clinical chemistry results obtained from diluted plasma samples for all analytes except aspartate aminotransferase, creatine kinase, and glucose. Uric acid concentration was not significantly different at dilutions of up to 1:3. Bile acids, globulins, and sodium concentrations were below the limit of detection in all diluted samples and were not statistically analyzed. Based on these results, dilution with sterile water is not recommended for biochemical analysis of avian plasma using the VetScan benchtop analyzer.

Chemistry of Mesoporous Organosilica in Nanotechnology: Molecularly Organic-Inorganic Hybridization into Frameworks.

PubMed

Chen, Yu; Shi, Jianlin

2016-05-01

Organic-inorganic hybrid materials aiming to combine the individual advantages of organic and inorganic components while overcoming their intrinsic drawbacks have shown great potential for future applications in broad fields. In particular, the integration of functional organic fragments into the framework of mesoporous silica to fabricate mesoporous organosilica materials has attracted great attention in the scientific community for decades. The development of such mesoporous organosilica materials has shifted from bulk materials to nanosized mesoporous organosilica nanoparticles (designated as MONs, in comparison with traditional mesoporous silica nanoparticles (MSNs)) and corresponding applications in nanoscience and nanotechnology. In this comprehensive review, the state-of-art progress of this important hybrid nanomaterial family is summarized, focusing on the structure/composition-performance relationship of MONs of well-defined morphology, nanostructure, and nanoparticulate dimension. The synthetic strategies and the corresponding mechanisms for the design and construction of MONs with varied morphologies, compositions, nanostructures, and functionalities are overviewed initially. Then, the following part specifically concentrates on their broad spectrum of applications in nanotechnology, mainly in nanomedicine, nanocatalysis, and nanofabrication. Finally, some critical issues, presenting challenges and the future development of MONs regarding the rational synthesis and applications in nanotechnology are summarized and discussed. It is highly expected that such a unique molecularly organic-inorganic nanohybrid family will find practical applications in nanotechnology, and promote the advances of this discipline regarding hybrid chemistry and materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solar photochemistry - twenty years of progress, what`s been accomplished, and where does it lead?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blake, D M

1995-01-01

It has been more than 20 years since the first oil embargo. That event created an awareness of the need for alternative sources of energy and renewed interest in combining sunlight and chemistry to produce the chemicals and materials required by industry. This paper will review approaches that have been taken, progress that has been made, and give some projections for the near and longer term prospects for commercialization of solar photochemistry.

Grade 12 Diploma Examination: Chemistry 30. January 1989 = Examen en vue du diplome douzieme annee: Chimie 30. Janvier 1989.

ERIC Educational Resources Information Center

Alberta Dept. of Education, Edmonton.

Chemistry 30 is a 12th-grade science course for students in Alberta, Canada. This document is the final test for the course. Intended for administration during January 1989, it contains 56 multiple-choice questions and three written-response questions. Two and one-half hours are allowed for completing the test. No answer key is included since…

Grade 12 Diploma Examination: Chemistry 30. January 1988 = Examen en vue du diplome douzieme annee: Chimie 30. Janvier 1988.

ERIC Educational Resources Information Center

Alberta Dept. of Education, Edmonton.

Chemistry 30 is a 12th-grade science course for students in Alberta, Canada. This document is the final test for the course. Intended for administration during January 1988, it contains 56 multiple-choice questions and three written-response questions. Two-and-one-half hours are allowed for completing the test. No answer key is included since…

Grade 12 Diploma Examination: Chemistry 30. June 1989 = Examen en vue du diplome douzieme annee: Chimie 30. Juin 1989.

ERIC Educational Resources Information Center

Alberta Dept. of Education, Edmonton.

Chemistry 30 is a 12th-grade science course for students in Alberta, Canada. This document is the final test for the course. Intended for administration during June 1989, it contains 56 multiple-choice questions and 3 written-response questions. Two-and-one-half hours are allowed for completing the test. No answer key is included since scoring is…

High-Performance Polymeric Materials.

DTIC Science & Technology

1987-12-07

Chemistry and the Polymer Research Center 4 The University of Cincinnati Final Report, November 1, 1982 October 31, 1987 f,! 5:;u - . Air Force Office of...Scientific Research N. Dec imber 11, 1987 -1- FOREWORD This report was prepared at the Department of Chemistry of the University of Cincinnati, under...Grant AFOSR 83-0027. The research described hereir was administereC under the direction of the Air Force Office of Scientific Research , Boiling Air Force

ANNUAL REPORT, JULY 1, 1960

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1961-10-31

Research facilities, general construction progress, research activities, and administration are discussed and a financial statement is given. Fairly detailed accounts are given of research programs in the fields of physics, accelerator development, instrumentation, applied mathematics, chemistry, nuclear engineering, biology, and medicine. (M.C.G.)

Placing Science into Its Human Context: Using Scientific Autobiography to Teach Chemistry

NASA Astrophysics Data System (ADS)

Carroll, Felix A.; Seeman, Jeffrey I.

2001-12-01

Scientific autobiography and biography can improve chemistry learning by helping students relate otherwise abstract concepts to important events in the lives of fellow human beings. In advanced courses, reading scientific autobiography and biography can help students see how scientific collaboration, advances in instrumentation, and major events in human lives influence the development of chemical ideas over time. In addition, studying many years of an individual's research program can demonstrate the progress of science, the connectivity of research findings, and the validity of experimental results over many decades. This paper describes the use of an autobiography of an eminent chemist in an advanced undergraduate chemistry course. This approach not only enhances the teaching of chemical concepts, but it also provides students with expanded opportunities for cooperative and self-directed learning activities.

Laboratory Sequence in Computational Methods for Introductory Chemistry

NASA Astrophysics Data System (ADS)

Cody, Jason A.; Wiser, Dawn C.

2003-07-01

A four-exercise laboratory sequence for introductory chemistry integrating hands-on, student-centered experience with computer modeling has been designed and implemented. The progression builds from exploration of molecular shapes to intermolecular forces and the impact of those forces on chemical separations made with gas chromatography and distillation. The sequence ends with an exploration of molecular orbitals. The students use the computers as a tool; they build the molecules, submit the calculations, and interpret the results. Because of the construction of the sequence and its placement spanning the semester break, good laboratory notebook practices are reinforced and the continuity of course content and methods between semesters is emphasized. The inclusion of these techniques in the first year of chemistry has had a positive impact on student perceptions and student learning.

Design of Bioinorganic Materials at the Interface of Coordination and Biosupramolecular Chemistry.

PubMed

Maity, Basudev; Ueno, Takafumi

2017-04-01

Protein assemblies have recently become known as potential molecular scaffolds for applications in materials science and bio-nanotechnology. Efforts to design protein assemblies for construction of protein-based hybrid materials with metal ions, metal complexes, nanomaterials and proteins now represent a growing field with a common aim of providing novel functions and mimicking natural functions. However, the important roles of protein assemblies in coordination and biosupramolecular chemistry have not been systematically investigated and characterized. In this personal account, we focus on our recent progress in rational design of protein assemblies using bioinorganic chemistry for (1) exploration of unnatural reactions, (2) construction of functional protein architectures, and (3) in vivo applications. © 2017 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spectroscopic Studies of Pre-Biotic Carbon Chemistry

NASA Technical Reports Server (NTRS)

Blake, Geoffrey A.

2003-01-01

As described in the original proposal and in our progress reports, research in the Blake group supported by the Exobiology program seeks to understand the pre-biotic chemistry of carbon along with that of other first- and second-row elements from the earliest stages of star formation through the development of planetary systems. The major tool used is spectroscopy, and the program has observational, laboratory, and theoretical components. The observational and theoretical programs are concerned primarily with a quantitative assessment of the chemical budgets of the biogenic elements in the circumstellar environment of forming stars and planetary systems, while the laboratory work is focused on the complex species that characterize the pre-biotic chemistry of carbon. We outline below our results over the past year acquired, in part, with Exobiology support.

Advances on Aryldiazonium Salt Chemistry Based Interfacial Fabrication for Sensing Applications.

PubMed

Cao, Chaomin; Zhang, Yin; Jiang, Cheng; Qi, Meng; Liu, Guozhen

2017-02-15

Aryldiazonium salts as coupling agents for surface chemistry have evidenced their wide applications for the development of sensors. Combined with advances in nanomaterials, current trends in sensor science and a variety of particular advantages of aryldiazonium salt chemistry in sensing have driven the aryldiazonium salt-based sensing strategies to grow at an astonishing pace. This review focuses on the advances in the use of aryldiazonium salts for modifying interfaces in sensors and biosensors during the past decade. It will first summarize the current methods for modification of interfaces with aryldiazonium salts, and then discuss the sensing applications of aryldiazonium salts modified on different transducers (bulky solid electrodes, nanomaterials modified bulky solid electrodes, and nanoparticles). Finally, the challenges and perspectives that aryldiazonium salt chemistry is facing in sensing applications are critically discussed.

Atmospheric Chemistry and Air Pollution

DOE PAGES

Gaffney, Jeffrey S.; Marley, Nancy A.

2003-01-01

Atmospheric chemistry is an important discipline for understanding air pollution and its impacts. This mini-review gives a brief history of air pollution and presents an overview of some of the basic photochemistry involved in the production of ozone and other oxidants in the atmosphere. Urban air quality issues are reviewed with a specific focus on ozone and other oxidants, primary and secondary aerosols, alternative fuels, and the potential for chlorine releases to amplify oxidant chemistry in industrial areas. Regional air pollution issues such as acid rain, long-range transport of aerosols and visibility loss, and the connections of aerosols to ozonemore » and peroxyacetyl nitrate chemistry are examined. Finally, the potential impacts of air pollutants on the global-scale radiative balances of gases and aerosols are discussed briefly.« less

Inorganic Nanotubes and Fullerene-like Nanoparticles at the Crossroads between Solid-State Chemistry and Nanotechnology.

PubMed

Višić, Bojana; Panchakarla, Leela Srinivas; Tenne, Reshef

2017-09-20

Inorganic nanotubes (NTs) and fullerene-like nanoparticles (NPs) of WS 2 were discovered some 25 years ago and are produced now on a commercial scale for various applications. This Perspective provides a brief description of recent progress in this scientific discipline. The conceptual evolution leading to the discovery of these NTs and NPs is briefly discussed. Subsequently, recent progress in the synthesis of such NPs from a variety of inorganic compounds with layered (2D) structure is described. In particular, we discuss the synthesis of NTs from chalcogenide- and oxide-based ternary misfit layered compounds, as well as their structure and different growth mechanisms. Next we deliberate on the mechanical, optical, electrical, and electromechanical properties, which delineate them from their bulk counterparts and also from their graphene-like analogues. Here, different experiments with individual NTs coupled with first-principles and molecular dynamics calculations demonstrate the unique physical nature of these quasi-1D nanostructures. Finally, the various applications of the fullerene-like NPs of WS 2 and NTs formed therefrom are deliberated. Foremost among the possibilities are their extensive uses as superior solid lubricants. Combined with their nontoxicity and their facile dispersion, these NTs, with an ultimate strength of about 20 GPa, are likely to find numerous applications in reinforcing polymers, adhesives, textiles, medical devices, metallic alloys, and even concrete. Other potential applications in energy-harvesting and catalysis are discussed in brief.

Multivariate statistical analysis and hydrogeochemical modelling of seawater-freshwater mixing along selected flow paths: Case of Korba coastal aquifer Tunisia

NASA Astrophysics Data System (ADS)

Slama, Fairouz; Bouhlila, Rachida

2017-11-01

Groundwater sampling and piezometric measurements were carried out along two flow paths (corresponding to two transects) in Korba coastal plain (Northeast of Tunisia). The study aims to identify hydrochemical processes occurring when seawater and freshwater mix. Those processes can be used as indicators of seawater intrusion progression and freshwater flushing into seawater accompanying Submarine Groundwater Discharge (SGD). Seawater fractions in the groundwater were calculated using the chloride concentration. Hierarchical cluster analysis (HCA) was applied to isolate wells potentially affected by seawater. In addition, PHREEQC was used to simulate the theoretical mixing between two end members: seawater and a fresh-brackish groundwater sample. Geochemical conventional diagrams showed that the groundwater chemistry is explained by a mixing process between two end members. Results also revealed the presence of other geochemical processes, correlated to the hydrodynamic flow paths. Direct cation exchange was linked to seawater intrusion, and reverse cation exchange was associated to the freshwater flushing into seawater. The presence of these processes indicated that seawater intrusion was in progress. An excess of Ca, that could not be explained by only cation exchange processes, was observed in both transects. Dedolomitization combined to gypsum leaching is the possible explanation of the groundwater Ca enrichment. Finally, redox processes were also found to contribute to the groundwater composition along flow paths.

Henry Taube and Coordination Chemistry

Science.gov Websites

Shifts Caused by Cr++ in Aqueous Solutions, DOE Technical Report, 1962 Reactions of Solvated Ions Final Report, DOE Technical Report, 1962 Isotopic Discrimination of Some Solutes in Liquid Ammonia, DOE Technical Report, 1966 Final Technical Report of Research, DOE Technical Report, 1972 Top Additional Web

Providing Computer-Based Information Services to an Academic Community. Final Technical Report.

ERIC Educational Resources Information Center

Bayer, Bernard

The Mechanized Information Center (MIC) at the Ohio State University conducts retrospective and current awareness searches for faculty, students, and staff using data bases for agriculture, chemistry, education, psychology, and social sciences, as well as a multidisciplinary data base. The final report includes (1) a description of the background…

Teaching Chemistry Lab Safety through Comics

NASA Astrophysics Data System (ADS)

di Raddo, Pasquale

2006-04-01

As a means for raising students' interest in aspects pertaining to chemistry lab safety, this article presents a novel approach to teaching this important subject. Comic book lab scenes that involve fictional characters familiar to many students are presented and discussed as to the safety concerns represented in those images. These are discussed in a safety prelab session. For the sake of comparison, students are then shown images taken from current chemistry journals of safety-conscious contemporary chemists at work in their labs. Finally the need to adhere to copyright regulations for the use of the images is discussed so as to increase students' awareness of academic honesty and copyright issues.

Carbohydrates in Supramolecular Chemistry.

PubMed

Delbianco, Martina; Bharate, Priya; Varela-Aramburu, Silvia; Seeberger, Peter H

2016-02-24

Carbohydrates are involved in a variety of biological processes. The ability of sugars to form a large number of hydrogen bonds has made them important components for supramolecular chemistry. We discuss recent advances in the use of carbohydrates in supramolecular chemistry and reveal that carbohydrates are useful building blocks for the stabilization of complex architectures. Systems are presented according to the scaffold that supports the glyco-conjugate: organic macrocycles, dendrimers, nanomaterials, and polymers are considered. Glyco-conjugates can form host-guest complexes, and can self-assemble by using carbohydrate-carbohydrate interactions and other weak interactions such as π-π interactions. Finally, complex supramolecular architectures based on carbohydrate-protein interactions are discussed.

Evaluation of different flamelet tabulation methods for laminar spray combustion

NASA Astrophysics Data System (ADS)

Luo, Yujuan; Wen, Xu; Wang, Haiou; Luo, Kun; Fan, Jianren

2018-05-01

In this work, three different flamelet tabulation methods for spray combustion are evaluated. Major differences among these methods lie in the treatment of the temperature boundary conditions of the flamelet equations. Particularly, in the first tabulation method ("M1"), both the fuel and oxidizer temperature boundary conditions are set to be fixed. In the second tabulation method ("M2"), the fuel temperature boundary condition is varied while the oxidizer temperature boundary condition is fixed. In the third tabulation method ("M3"), both the fuel and oxidizer temperature boundary conditions are varied and set to be equal. The focus of this work is to investigate whether the heat transfer between the droplet phase and gas phase can be represented by the studied tabulation methods through a priori analyses. To this end, spray flames stabilized in a three-dimensional counterflow are first simulated with detailed chemistry. Then, the trajectory variables are calculated from the detailed chemistry solutions. Finally, the tabulated thermo-chemical quantities are compared to the corresponding values from the detailed chemistry solutions. The comparisons show that the gas temperature cannot be predicted by "M1" with only a mixture fraction and reaction progress variable being the trajectory variables. The gas temperature can be correctly predicted by both "M2" and "M3," in which the total enthalpy is introduced as an additional manifold. In "M2," variations of the oxidizer temperature are considered with a temperature modification technique, which is not required in "M3." Interestingly, it is found that the mass fractions of the reactants and major products are not sensitive to the representation of the interphase heat transfer in the flamelet chemtables, and they can be correctly predicted by all tabulation methods. By contrast, the intermediate species CO and H2 in the premixed flame reaction zone are over-predicted by all tabulation methods.

Analytical Chemistry Laboratory. Progress report for FY 1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, D.W.; Boparai, A.S.; Bowers, D.L.

The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year (FY) 1996. This annual report is the thirteenth for the ACL. It describes effort on continuing and new projects and contributions of the ACL staff to various programs at ANL. The ACL operates in the ANL system as a full-cost-recovery service center, but has a mission that includes a complementary research and development component: The Analytical Chemistry Laboratory will provide high-quality, cost-effective chemical analysis and related technical support to solve research problems of our clients --more » Argonne National Laboratory, the Department of Energy, and others -- and will conduct world-class research and development in analytical chemistry and its applications. Because of the diversity of research and development work at ANL, the ACL handles a wide range of analytical chemistry problems. Some routine or standard analyses are done, but the ACL usually works with commercial laboratories if our clients require high-volume, production-type analyses. It is common for ANL programs to generate unique problems that require significant development of methods and adaption of techniques to obtain useful analytical data. Thus, much of the support work done by the ACL is very similar to our applied analytical chemistry research.« less

Recent progress of dopant-free organic hole-transporting materials in perovskite solar cells

NASA Astrophysics Data System (ADS)

Dongxue, Liu; Liu, Yongsheng

2017-01-01

Organic-inorganic hybrid perovskite solar cells have undergone especially intense research and transformation over the past seven years due to their enormous progress in conversion efficiencies. In this perspective, we review the latest developments of conventional perovskite solar cells with a main focus on dopant-free organic hole transporting materials (HTMs). Regarding the rapid progress of perovskite solar cells, stability of devices using dopant-free HTMs are also discussed to help readers understand the challenges and opportunities in high performance and stable perovskite solar cells. Project supported by the Scientific Research Starting Foundation for Overseas Introduced Talents of College of Chemistry, Nankai University.

Kinetics and Product Channels in Combustion Chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hershberger, John F.

We report study of the chemical kinetics and/or photochemistry of several chemical reactions of potential interest in understanding the gas phase combustion chemistry of nitrogen-containing molecules. Studies completed during the final grant period include determination of quantum yields of the photolysis of HCNO, fulminic acid, a kinetics and product channel study of the reaction of CN radicals with methyl bromide, and study of the products of the reaction of hydroxymethyl radical with nitric oxide.

The Professorial Career of Clifford R. Haymaker: A Life of Chemistry Imagined and Bequeathed

NASA Astrophysics Data System (ADS)

Eisch, John J.; Haworth, Daniel T.

2003-03-01

The professorial career of Clifford R. Haymaker (1907-1981), a longtime professor of organic chemistry at Marquette University, constitutes a most inspiring triumph of the human spirit over physical disabilities. Blind from birth, he was endowed with exceptional powers of imagination and analysis, and he excelled in both primary and secondary schools through the tutoring of his mother and the help of his sighted classmates and teachers. Despite his blindness, he embarked upon the study of chemistry at Marquette in 1925. Again with the aid of readers and sighted laboratory classmates he obtained the B.S. degree in 1929, the M.S. degree in 1933 and finally the Ph.D. degree in 1938 for the literature study, "The Chemistry of Atomic Nuclei". Beginning as instructor of organic chemistry in 1929 and retiring as professor of chemistry in 1973, Clifford Haymaker offered lectures on theoretical and experimental organic chemistry to countless undergraduate and graduate students with a clarity and vividness that were both greatly appreciated and admired. He was a great advocate of chemical research and inspired many students to undertake studies for advance degrees in chemistry or allied sciences. The authors of this article offer personal comments on how Clifford Haymaker has influenced their careers.

Research for the advancement of green chemistry practice: Studies in atmospheric and educational chemistry

NASA Astrophysics Data System (ADS)

Cullipher, Steven Gene

Green chemistry is a philosophy of chemistry that emphasizes a decreasing dependence on limited non-renewable resources and an increasing focus on preventing pollution byproducts of the chemical industry. In short, it is the discipline of chemistry practiced through the lens of environmental stewardship. In an effort to advance the practice of green chemistry, three studies will be described that have ramifications for the practice. The first study examines the atmospheric oxidation of a hydrofluorinated ether, a third-generation CFC replacement compound with primarily unknown atmospheric degradation products. Determination of these products has the potential to impact decisions on refrigerant usage in the future. The second study examines chemistry students' development of understanding benefits-costs-risks analysis when presented with two real-world scenarios: refrigerant choice and fuel choice. By studying how benefits-costs-risks thinking develops, curricular materials and instructional approaches can be designed to better foster the development of an ability that is both necessary for green chemists and important in daily decision-making for non-chemists. The final study uses eye tracking technology to examine students' abilities to interpret molecular properties from structural information in the context of global warming. Such abilities are fundamental if chemists are to appropriately assess risks and hazards of chemistry practice.

Cold molecules: Progress in quantum engineering of chemistry and quantum matter

NASA Astrophysics Data System (ADS)

Bohn, John L.; Rey, Ana Maria; Ye, Jun

2017-09-01

Cooling atoms to ultralow temperatures has produced a wealth of opportunities in fundamental physics, precision metrology, and quantum science. The more recent application of sophisticated cooling techniques to molecules, which has been more challenging to implement owing to the complexity of molecular structures, has now opened the door to the longstanding goal of precisely controlling molecular internal and external degrees of freedom and the resulting interaction processes. This line of research can leverage fundamental insights into how molecules interact and evolve to enable the control of reaction chemistry and the design and realization of a range of advanced quantum materials.

Enabling Technologies for the Future of Chemical Synthesis

PubMed Central

2016-01-01

Technology is evolving at breakneck pace, changing the way we communicate, travel, find out information, and live our lives. Yet chemistry as a science has been slower to adapt to this rapidly shifting world. In this Outlook we use highlights from recent literature reports to describe how progresses in enabling technologies are altering this trend, permitting chemists to incorporate new advances into their work at all levels of the chemistry development cycle. We discuss the benefits and challenges that have arisen, impacts on academic–industry relationships, and future trends in the area of chemical synthesis. PMID:27163040

The medicinal chemistry of liver X receptor (LXR) modulators.

PubMed

Tice, Colin M; Noto, Paul B; Fan, Kristi Yi; Zhuang, Linghang; Lala, Deepak S; Singh, Suresh B

2014-09-11

LXRs have been of interest as targets for the treatment of atherosclerosis for over a decade. In recent years, LXR modulators have also garnered interest for potential use in the treatment of inflammation, Alzheimer's disease (AD), dermatological conditions, hepatic steatosis, and oncology. To date, no LXR modulator has successfully progressed beyond phase I clinical trials. In this Perspective, we summarize published medicinal chemistry efforts in the context of the available crystallographic data, druglikeness, and isoform selectivity. In addition, we discuss the challenges that need to be overcome before an LXR modulator can reach clinical use.

Quarterly progress report for the Chemical and Energy Research Section of the Chemical Technology Division, April--June 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jubin, R.T.

The Chemical and Energy Research Section conducts basic and applied research and development in chemical engineering, applied chemistry, and bioprocessing, with an emphasis on energy-driven technologies and advanced chemical separations for nuclear and waste applications. The report describes the various tasks performed within six major areas of research: Hot Cell Operations, Process Chemistry and thermodynamics, Separations and Materials Synthesis, Solution Thermodynamics, biotechnology Research, and Molecular Studies. The name of a technical contact is included with each task described, and readers are encouraged to contact these individuals if they need additional information.

From Carver to Hill, and On.

ERIC Educational Resources Information Center

Massie, Samuel P.

The story of blacks in chemistry is one of determination, expectation, participation and contribution. Between 1910 and 1945, despite George Washington Carver's significant agricultural contributions and St. Elmo Brady's scholarship, white graduate schools and industry had little interest in accepting blacks. There was slow progress, despite these…

A preliminary model of the coma of 2060 Chiron

NASA Technical Reports Server (NTRS)

Boice, Daniel C.; Konno, I.; Stern, S. Alan; Huebner, Walter F.

1992-01-01

We have included gravity in our fluid dynamic model with chemical kinetics of dusty comet comae and applied it with two dust sizes to 2060 Chiron. A progress report on the model and preliminary results concerning gas/dust dynamics and chemistry is given.

The practical and fundamental limits of optical imaging in mammalian brains.

PubMed

Ji, Na

2014-09-17

Advances in chemistry and physics have profound effects on neuroimaging. Current and future progress in these disciplines will continue to aid in efforts to visualize neural circuitry, particularly in deeper layers of the brain. Copyright © 2014 Elsevier Inc. All rights reserved.

Building bridges between the physical and biological sciences.

PubMed

Ninham, B W; Boström, M

2005-12-16

This paper attempts to identify major conceptual issues that have inhibited the application of physical chemistry to problems in the biological sciences. We will trace out where theories went wrong, how to repair the present foundations, and discuss current progress toward building a better dialogue.

Analytical Chemistry Division annual progress report for period ending November 30, 1977

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lyon, W.S.

1978-03-01

Activities for the year are summarized in sections on analytical methodology, mass and mass emission spectrometry, analytical services, bio-organic analysis, nuclear and radiochemical analysis, and quality assurance and safety. Presentations of research results in publications and reports are tabulated. (JRD)

"Eureka, Eureka!" Discoveries in Science

ERIC Educational Resources Information Center

Agarwal, Pankaj

2011-01-01

Accidental discoveries have been of significant value in the progress of science. Although accidental discoveries are more common in pharmacology and chemistry, other branches of science have also benefited from such discoveries. While most discoveries are the result of persistent research, famous accidental discoveries provide a fascinating…

MELCOR/CONTAIN LMR Implementation Report-Progress FY15

DOE Office of Scientific and Technical Information (OSTI.GOV)

Humphries, Larry L.; Louie, David L.Y.

2016-01-01

This report describes the progress of the CONTAIN-LMR sodium physics and chemistry models to be implemented in to MELCOR 2.1. It also describes the progress to implement these models into CONT AIN 2 as well. In the past two years, the implementation included the addition of sodium equations of state and sodium properties from two different sources. The first source is based on the previous work done by Idaho National Laborat ory by modifying MELCOR to include liquid lithium equation of state as a working fluid to mode l the nuclear fusion safety research. The second source uses properties generatedmore » for the SIMMER code. Testing and results from this implementation of sodium pr operties are given. In addition, the CONTAIN-LMR code was derived from an early version of C ONTAIN code. Many physical models that were developed sin ce this early version of CONTAIN are not captured by this early code version. Therefore, CONTAIN 2 is being updated with the sodium models in CONTAIN-LMR in or der to facilitate verification of these models with the MELCOR code. Although CONTAIN 2, which represents the latest development of CONTAIN, now contains ma ny of the sodium specific models, this work is not complete due to challenges from the lower cell architecture in CONTAIN 2, which is different from CONTAIN- LMR. This implementation should be completed in the coming year, while sodi um models from C ONTAIN-LMR are being integrated into MELCOR. For testing, CONTAIN decks have been developed for verification and validation use. In terms of implementing the sodium m odels into MELCOR, a separate sodium model branch was created for this document . Because of massive development in the main stream MELCOR 2.1 code and the require ment to merge the latest code version into this branch, the integration of the s odium models were re-directed to implement the sodium chemistry models first. This change led to delays of the actual implementation. For aid in the future implementation of sodium models, a new sodium chemistry package was created. Thus reporting for the implementation of the sodium chemistry is discussed in this report.« less

Student academic achievement in college chemistry

NASA Astrophysics Data System (ADS)

Tabibzadeh, Kiana S.

General Chemistry is required for variety of baccalaureate degrees, including all medical related fields, engineering, and science majors. Depending on the institution, the prerequisite requirement for college level General Chemistry varies. The success rate for this course is low. The purpose of this study is to examine the factors influencing student academic achievement and retention in General Chemistry at the college level. In this study student achievement is defined by those students who earned grades of "C" or better. The dissertation contains in-depth studies on influence of Intermediate Algebra as a prerequisite compared to Fundamental Chemistry for student academic achievement and student retention in college General Chemistry. In addition the study examined the extent and manner in which student self-efficacy influences student academic achievement in college level General Chemistry. The sample for this part of the study is 144 students enrolled in first semester college level General Chemistry. Student surveys determined student self-efficacy level. The statistical analyses of study demonstrated that Fundamental Chemistry is a better prerequisite for student academic achievement and student retention. The study also found that student self-efficacy has no influence on student academic achievement. The significance of this study will be to provide data for the purpose of establishing a uniform and most suitable prerequisite for college level General Chemistry. Finally the variables identified to influence student academic achievement and enhance student retention will support educators' mission to maximize the students' ability to complete their educational goal at institutions of higher education.

Microsystem technology as a road from macro to nanoworld.

PubMed

Grabiec, Piotr; Domański, Krzysztof; Janus, Paweł; Zaborowski, Michał; Jaroszewicz, Bogdan

2005-04-01

Tremendous progress of microelectronic technology observed within last 40 years is closely related to even more remarkable progress of technological tools. It is important to note however, that these new tools may be used for fabrication of diverse multifunctional structures as well. Such devices, called MEMS (Micro-Electro-Mechanical-System) and MOEMS (Micro-Electro-Opto-Mechanical-System) integrate microelectronic and micromechanical structures in one system enabling interdisciplinary application, with most interesting and prospective being bio-medical investigations. Development of these applications requires however cooperation of multidisciplinary team of specialists, covering broad range of physics, (bio) chemistry and electronics, not mentioning medical doctors and other medical specialists. Thus, dissemination, of knowledge about existing processing capabilities is of key importance. In this paper, examples of various applications of microelectronic technology for fabrication of Microsystems which may be used for medicine and chemistry, will be presented. Besides, information concerning a design and technology potential available in poland and new, emerging opportunities will be given.

Structure–property relationships in atomic-scale junctions: Histograms and beyond

DOE PAGES

Mark S. Hybertsen; Venkataraman, Latha

2016-03-03

Over the past 10 years, there has been tremendous progress in the measurement, modeling and understanding of structure–function relationships in single molecule junctions. Numerous research groups have addressed significant scientific questions, directed both to conductance phenomena at the single molecule level and to the fundamental chemistry that controls junction functionality. Many different functionalities have been demonstrated, including single-molecule diodes, optically and mechanically activated switches, and, significantly, physical phenomena with no classical analogues, such as those based on quantum interference effects. Experimental techniques for reliable and reproducible single molecule junction formation and characterization have led to this progress. In particular, themore » scanning tunneling microscope based break-junction (STM-BJ) technique has enabled rapid, sequential measurement of large numbers of nanoscale junctions allowing a statistical analysis to readily distinguish reproducible characteristics. Furthermore, harnessing fundamental link chemistry has provided the necessary chemical control over junction formation, enabling measurements that revealed clear relationships between molecular structure and conductance characteristics.« less

Structure–property relationships in atomic-scale junctions: Histograms and beyond

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mark S. Hybertsen; Venkataraman, Latha

Over the past 10 years, there has been tremendous progress in the measurement, modeling and understanding of structure–function relationships in single molecule junctions. Numerous research groups have addressed significant scientific questions, directed both to conductance phenomena at the single molecule level and to the fundamental chemistry that controls junction functionality. Many different functionalities have been demonstrated, including single-molecule diodes, optically and mechanically activated switches, and, significantly, physical phenomena with no classical analogues, such as those based on quantum interference effects. Experimental techniques for reliable and reproducible single molecule junction formation and characterization have led to this progress. In particular, themore » scanning tunneling microscope based break-junction (STM-BJ) technique has enabled rapid, sequential measurement of large numbers of nanoscale junctions allowing a statistical analysis to readily distinguish reproducible characteristics. Furthermore, harnessing fundamental link chemistry has provided the necessary chemical control over junction formation, enabling measurements that revealed clear relationships between molecular structure and conductance characteristics.« less

The relative role of "A" level chemistry, physics and biology in the medical course.

PubMed

Tomilson, R W; Clack, G B; Pettingale, K W; Anderson, J; Ryan, K C

1977-03-01

The performance of 209 students in the 2nd MBBS, first clinical year and final MBBS examinations has been compared retrospectively with their grades in chemistry, physics and biology at "A" level. The mean grade has also been determined for students from different social classes and secondary education. Significant differences in marks for biology were found between successful and not so successful students, especially in the pre-clinical part of the course. Significnat differences in marks and significant correlations were also found for physics but not to any great extent for chemistry. The relative role of these three basic sciences in the medical course is discussed. The suggestion is made that there is a need for a re-appraisal of the privleged position of chemistry and an unquestioned science requirement for entry to medical school.

Extending atomistic scale chemistry to mesoscale model of condensed-phase deflagration

NASA Astrophysics Data System (ADS)

Joshi, Kaushik; Chaudhuri, Santanu

2017-01-01

Predictive simulations connecting chemistry that follow the shock or thermal initiation of energetic materials to subsequent deflagration or detonation events is currently outside the realm of possibilities. Molecular dynamics and first-principles based dynamics have made progress in understanding reactions in picosecond to nanosecond time scale. Results from thermal ignition of different phases of RDX show a complex reaction network and emergence of a deterministic behavior for critical temperature before ignition and hot spot growth rates. The kinetics observed is dependent on the hot spot temperature, system size and thermal conductivity. For cases where ignition is observed, the incubation period is dominated by intermolecular and intramolecular hydrogen transfer reactions. The gradual temperature and pressure increase in the incubation period is accompanied by accumulation of heavier polyradicals. The challenge of connecting such chemistry in mesoscale simulations remain in reducing the complexity of chemistry. The hot spot growth kinetics in RDX grains and interfaces is an important challenge for reactive simulations aiming to fill in the gaps in our knowledge in the nanoseconds to microseconds time scale. The results discussed indicate that the mesoscale chemistry may include large polyradical molecules in dense reactive mix reaching an instability point at certain temperatures and pressures.

Dilution physics modeling: Dissolution/precipitation chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onishi, Y.; Reid, H.C.; Trent, D.S.

This report documents progress made to date on integrating dilution/precipitation chemistry and new physical models into the TEMPEST thermal-hydraulics computer code. Implementation of dissolution/precipitation chemistry models is necessary for predicting nonhomogeneous, time-dependent, physical/chemical behavior of tank wastes with and without a variety of possible engineered remediation and mitigation activities. Such behavior includes chemical reactions, gas retention, solids resuspension, solids dissolution and generation, solids settling/rising, and convective motion of physical and chemical species. Thus this model development is important from the standpoint of predicting the consequences of various engineered activities, such as mitigation by dilution, retrieval, or pretreatment, that can affectmore » safe operations. The integration of a dissolution/precipitation chemistry module allows the various phase species concentrations to enter into the physical calculations that affect the TEMPEST hydrodynamic flow calculations. The yield strength model of non-Newtonian sludge correlates yield to a power function of solids concentration. Likewise, shear stress is concentration-dependent, and the dissolution/precipitation chemistry calculations develop the species concentration evolution that produces fluid flow resistance changes. Dilution of waste with pure water, molar concentrations of sodium hydroxide, and other chemical streams can be analyzed for the reactive species changes and hydrodynamic flow characteristics.« less

Turbine Chemistry Modeling

NASA Technical Reports Server (NTRS)

Liu, Nan-Suey; Wey, Thomas

2001-01-01

Many of the engine exhaust species resulting in significant environmental impact exist in trace amounts. Recent research, e.g., conducted at MIT-AM, has pointed to the intra-engine environment as a possible site for important trace chemistry activity. In addition, the key processes affecting the trace species activity occurring downstream in the air passages of the turbine and exhaust nozzle are not well understood. Most recently, an effort has been initiated at NASA Glenn Research Center under the UEET Program to evaluate and further develop CFD-based technology for modeling and simulation of intra-engine trace chemical changes relevant to atmospheric effects of pollutant emissions from aircraft engines. This presentation will describe the current effort conducted at Glenn; some preliminary results relevant to the trace species chemistry in a turbine passage will also be presented to indicate the progress to date.

Final Progress Report for Ionospheric Dusty Plasma In the Laboratory [Smokey Plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robertson, Scott

2010-07-31

“Ionospheric Dusty Plasma in the Laboratory” is a research project with the purpose of finding and reproducing the characteristics of plasma in the polar mesosphere that is unusually cold (down to 140 K) and contains nanometer-sized dust particles. This final progress report summarizes results from four years of effort that include a final year with a no-cost extension.

Correlation of preadmission organic chemistry courses and academic performance in biochemistry at a midwest chiropractic doctoral program.

PubMed

McRae, Marc P

2010-01-01

Organic chemistry has been shown to correlate with academic success in the preclinical years of medicine, dentistry, and graduate physiology. The purpose of this study is to examine the relationship between undergraduate organic chemistry grades and first-semester biochemistry grades at a Midwest chiropractic doctoral program. Students enrolled in a first-semester biochemistry course who had completed the prerequisite courses in organic chemistry offered at this same institution were entered into the study. The total grade for each of the three courses was calculated using the midterm and final exam raw scores with a weighting of 50% each. Analysis consisted of obtaining correlation coefficients between the total grades of organic 1 with biochemistry and organic 2 with biochemistry. Using the biochemistry total grade, the students were divided into quartiles and course grades for both organic chemistry 1 and 2 were calculated. For the 109 students in the study, the correlation coefficient between the biochemistry and organic chemistry 1 and biochemistry and organic chemistry 2 courses was r = 0.744 and r = 0.725, respectively. The difference in organic chemistry grades between those in the first and fourth quartiles was 63.2% and 86.9% for organic chemistry 1 (p < .001) and 60.9% and 79.4% for organic chemistry 2 (p < .001). This study shows that organic chemistry can be used as an indicator of future academic success in a chiropractic biochemistry course. Knowledge of such a relationship could prove useful to identify students who may potentially run into academic difficulty with first-year biochemistry.

An Aerosol Physical Chemistry Model for the Upper Troposphere

NASA Technical Reports Server (NTRS)

Lin, Jin-Sheng

2001-01-01

This report is the final report for the Cooperative Agreement NCC2-1000. The tasks outlined in the various proposals are: (1) Development of an aerosol chemistry model; (2) Utilization of satellite measurements of trace gases along with analysis of temperatures and dynamic conditions to understand ice cloud formation, dehydration and sedimentation in the winter polar regions; (3) Comparison of the HALOE and SAGE II time dependencies of the Pinatubo aerosol decay. The publications are attached.

Research in Inorganic Fluorine Chemistry

DTIC Science & Technology

1991-05-28

n >*2F* EL JUL.l 8 1995 i 1 ^0 ^9^> ( 00 coll RESEARCH IN INORGANIC FLUORINE CHEMISTRY FINAL REPORT RI/RD91-165 Period 1 April...1988 - 31 March 1991 Prepared for: U. S. A3MY RESEARCH OFFICE RESEARCH TRIANGLE PARK, NC 27709 A Report on Work Sponsored by the U. S. Army... Research Office, under Contract DAAL03-88-C-0005 Approved for public release; distribution unlimited Reproduction in whole or in pan is permitted for

Chemical calculations on Cray computers

NASA Technical Reports Server (NTRS)

Taylor, Peter R.; Bauschlicher, Charles W., Jr.; Schwenke, David W.

1989-01-01

The influence of recent developments in supercomputing on computational chemistry is discussed with particular reference to Cray computers and their pipelined vector/limited parallel architectures. After reviewing Cray hardware and software the performance of different elementary program structures are examined, and effective methods for improving program performance are outlined. The computational strategies appropriate for obtaining optimum performance in applications to quantum chemistry and dynamics are discussed. Finally, some discussion is given of new developments and future hardware and software improvements.

Moving Beyond Boron: The Emergence of New Linkage Chemistries in Covalent Organic Frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeBlase, Catherine R.; Dichtel, William R.

Since their discovery in 2005, covalent organic frameworks (COFs) have attracted interest as potential materials for gas storage, catalysis, energy storage, and other applications because of their ability to periodically and reliably organize designed functionality into high surface area materials. Most of the first examples relied on boron-containing linkages, which suffer from hydrolytic and oxidative instability that limit their utility. In this Perspective, we describe the trend toward more robust linkages by highlighting the design, synthesis, and properties of several recent examples. Finally, the continued development of new COF chemistries, along with improved understanding of their formation and control ofmore » their final form, will provide a means to harness their molecularly precise solidstate structures for useful purposes.« less

Moving Beyond Boron: The Emergence of New Linkage Chemistries in Covalent Organic Frameworks

DOE PAGES

DeBlase, Catherine R.; Dichtel, William R.

2016-06-21

Since their discovery in 2005, covalent organic frameworks (COFs) have attracted interest as potential materials for gas storage, catalysis, energy storage, and other applications because of their ability to periodically and reliably organize designed functionality into high surface area materials. Most of the first examples relied on boron-containing linkages, which suffer from hydrolytic and oxidative instability that limit their utility. In this Perspective, we describe the trend toward more robust linkages by highlighting the design, synthesis, and properties of several recent examples. Finally, the continued development of new COF chemistries, along with improved understanding of their formation and control ofmore » their final form, will provide a means to harness their molecularly precise solidstate structures for useful purposes.« less

Application of a Model for Simulating the Vacuum Arc Remelting Process in Titanium Alloys

NASA Astrophysics Data System (ADS)

Patel, Ashish; Tripp, David W.; Fiore, Daniel

Mathematical modeling is routinely used in the process development and production of advanced aerospace alloys to gain greater insight into system dynamics and to predict the effect of process modifications or upsets on final properties. This article describes the application of a 2-D mathematical VAR model presented in previous LMPC meetings. The impact of process parameters on melt pool geometry, solidification behavior, fluid-flow and chemistry in Ti-6Al-4V ingots will be discussed. Model predictions were first validated against the measured characteristics of industrially produced ingots, and process inputs and model formulation were adjusted to match macro-etched pool shapes. The results are compared to published data in the literature. Finally, the model is used to examine ingot chemistry during successive VAR melts.

Bibliography on carbohydrate synthesis. Selected works, 1861 - 1981

NASA Technical Reports Server (NTRS)

Dufour, P. A.

1981-01-01

International in scope, this bibliography cites 220 articles books, patents, and conference proceedings related to carbohydrate synthesis. The works are listed alphabetically by author in the following categories: (1) experimental and industrial chemistry; (2) space travel and feeding studies; (3) hardware; and (4) general reviews and progress.

Urban Air Pollution: State of the Science.

ERIC Educational Resources Information Center

Seinfeld, John H.

1989-01-01

Describes the highly complex mixture of gaseous and particulate matter found in urban air. Explains progress made in the understanding of the physics and chemistry of air pollution, the effects of precursors on ozone, the role of biogenic hydrocarbons, and the principal benefit of methanol-fueled vehicles. (RT)

Trace element and isotope deposition across the air-sea interface: progress and research needs

NASA Astrophysics Data System (ADS)

Baker, A. R.; Landing, W. M.; Bucciarelli, E.; Cheize, M.; Fietz, S.; Hayes, C. T.; Kadko, D.; Morton, P. L.; Rogan, N.; Sarthou, G.; Shelley, R. U.; Shi, Z.; Shiller, A.; van Hulten, M. M. P.

2016-11-01

The importance of the atmospheric deposition of biologically essential trace elements, especially iron, is widely recognized, as are the difficulties of accurately quantifying the rates of trace element wet and dry deposition and their fractional solubility. This paper summarizes some of the recent progress in this field, particularly that driven by the GEOTRACES, and other, international research programmes. The utility and limitations of models used to estimate atmospheric deposition flux, for example, from the surface ocean distribution of tracers such as dissolved aluminium, are discussed and a relatively new technique for quantifying atmospheric deposition using the short-lived radionuclide beryllium-7 is highlighted. It is proposed that this field will advance more rapidly by using a multi-tracer approach, and that aerosol deposition models should be ground-truthed against observed aerosol concentration data. It is also important to improve our understanding of the mechanisms and rates that control the fractional solubility of these tracers. Aerosol provenance and chemistry (humidity, acidity and organic ligand characteristics) play important roles in governing tracer solubility. Many of these factors are likely to be influenced by changes in atmospheric composition in the future. Intercalibration exercises for aerosol chemistry and fractional solubility are an essential component of the GEOTRACES programme. This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

Trace element and isotope deposition across the air-sea interface: progress and research needs.

PubMed

Baker, A R; Landing, W M; Bucciarelli, E; Cheize, M; Fietz, S; Hayes, C T; Kadko, D; Morton, P L; Rogan, N; Sarthou, G; Shelley, R U; Shi, Z; Shiller, A; van Hulten, M M P

2016-11-28

The importance of the atmospheric deposition of biologically essential trace elements, especially iron, is widely recognized, as are the difficulties of accurately quantifying the rates of trace element wet and dry deposition and their fractional solubility. This paper summarizes some of the recent progress in this field, particularly that driven by the GEOTRACES, and other, international research programmes. The utility and limitations of models used to estimate atmospheric deposition flux, for example, from the surface ocean distribution of tracers such as dissolved aluminium, are discussed and a relatively new technique for quantifying atmospheric deposition using the short-lived radionuclide beryllium-7 is highlighted. It is proposed that this field will advance more rapidly by using a multi-tracer approach, and that aerosol deposition models should be ground-truthed against observed aerosol concentration data. It is also important to improve our understanding of the mechanisms and rates that control the fractional solubility of these tracers. Aerosol provenance and chemistry (humidity, acidity and organic ligand characteristics) play important roles in governing tracer solubility. Many of these factors are likely to be influenced by changes in atmospheric composition in the future. Intercalibration exercises for aerosol chemistry and fractional solubility are an essential component of the GEOTRACES programme.This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'. © 2015 The Authors.

Using the tabulated diffusion flamelet model ADF-PCM to simulate a lifted methane-air jet flame

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michel, Jean-Baptiste; Colin, Olivier; Angelberger, Christian

2009-07-15

Two formulations of a turbulent combustion model based on the approximated diffusion flame presumed conditional moment (ADF-PCM) approach [J.-B. Michel, O. Colin, D. Veynante, Combust. Flame 152 (2008) 80-99] are presented. The aim is to describe autoignition and combustion in nonpremixed and partially premixed turbulent flames, while accounting for complex chemistry effects at a low computational cost. The starting point is the computation of approximate diffusion flames by solving the flamelet equation for the progress variable only, reading all chemical terms such as reaction rates or mass fractions from an FPI-type look-up table built from autoigniting PSR calculations using complexmore » chemistry. These flamelets are then used to generate a turbulent look-up table where mean values are estimated by integration over presumed probability density functions. Two different versions of ADF-PCM are presented, differing by the probability density functions used to describe the evolution of the stoichiometric scalar dissipation rate: a Dirac function centered on the mean value for the basic ADF-PCM formulation, and a lognormal function for the improved formulation referenced ADF-PCM{chi}. The turbulent look-up table is read in the CFD code in the same manner as for PCM models. The developed models have been implemented into the compressible RANS CFD code IFP-C3D and applied to the simulation of the Cabra et al. experiment of a lifted methane jet flame [R. Cabra, J. Chen, R. Dibble, A. Karpetis, R. Barlow, Combust. Flame 143 (2005) 491-506]. The ADF-PCM{chi} model accurately reproduces the experimental lift-off height, while it is underpredicted by the basic ADF-PCM model. The ADF-PCM{chi} model shows a very satisfactory reproduction of the experimental mean and fluctuating values of major species mass fractions and temperature, while ADF-PCM yields noticeable deviations. Finally, a comparison of the experimental conditional probability densities of the progress variable for a given mixture fraction with model predictions is performed, showing that ADF-PCM{chi} reproduces the experimentally observed bimodal shape and its dependency on the mixture fraction, whereas ADF-PCM cannot retrieve this shape. (author)« less

PSI-Center Final Progress Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jarboe, Thomas R.; Shumlak, Uri; Sovinec, Carl

This is the Final Progress Report of the Plasma Science and Innovation Center (PSI-Center) covering March 2014 through February 2017. The Center has accomplished a great deal during this period. The PSI-Center is organized into four groups: Edge and Dynamic Neutrals; Transport and Kinetic Effects; Equilibrium, Stability, and Kinetic Effects in 3D Topologies; and Interface for Validation. Each group has made good progress and the results from each group are given in detail.

A Hartree-Fock Application Using UPC++ and the New DArray Library

DOE PAGES

Ozog, David; Kamil, Amir; Zheng, Yili; ...

2016-07-21

The Hartree-Fock (HF) method is the fundamental first step for incorporating quantum mechanics into many-electron simulations of atoms and molecules, and it is an important component of computational chemistry toolkits like NWChem. The GTFock code is an HF implementation that, while it does not have all the features in NWChem, represents crucial algorithmic advances that reduce communication and improve load balance by doing an up-front static partitioning of tasks, followed by work stealing whenever necessary. To enable innovations in algorithms and exploit next generation exascale systems, it is crucial to support quantum chemistry codes using expressive and convenient programming modelsmore » and runtime systems that are also efficient and scalable. Here, this paper presents an HF implementation similar to GTFock using UPC++, a partitioned global address space model that includes flexible communication, asynchronous remote computation, and a powerful multidimensional array library. UPC++ offers runtime features that are useful for HF such as active messages, a rich calculus for array operations, hardware-supported fetch-and-add, and functions for ensuring asynchronous runtime progress. We present a new distributed array abstraction, DArray, that is convenient for the kinds of random-access array updates and linear algebra operations on block-distributed arrays with irregular data ownership. Finally, we analyze the performance of atomic fetch-and-add operations (relevant for load balancing) and runtime attentiveness, then compare various techniques and optimizations for each. Our optimized implementation of HF using UPC++ and the DArrays library shows up to 20% improvement over GTFock with Global Arrays at scales up to 24,000 cores.« less

Improving TCO-Conjugated Antibody Reactivity for Bioorthogonal Pretargeting

NASA Astrophysics Data System (ADS)

Chu, Tina Tingyi

Cancer remains a major cause of death because of its unpredictable progression. Utilizing bioorthogonal chemistry between trans-cyclooctene (TCO) and tetrazine to target imaging agents to tumors in two subsequent steps offers a more versatile platform for molecular imaging. This is accomplished by pretargeting TCO-modified primary antibody to cell surface biomarkers, followed by delivery of tetrazine-modified imaging probes. In previous work, it has been established that TCO-tetrazine chemistry can be applied to in vivo imaging, resulting in precise tumor detection. However, most TCO modifications on an antibody are not reactive because they are buried within hydrophobic domains. To expose and improve the reactivity, Rahim et al. incorporated a polyethylene glycol (PEG) linker through a two-step reaction with DBCO-azide, which successfully maintained 100% TCO functionality. In this project, various types of linkers were studied to improve the reactivity in a single step. Three primary types of linkers were studied: hydrophilic PEG chains, hydrophobic short linkers, and amphiphilic linkers. Our results show that PEG chain alone can only maintain 40% TCO reactivity. Unexpectedly, a short alkyl chain (valeric acid) provided superior results, with 60% TCO reactivity. Lengthening the alkyl chain did not improve results further. Finally, an amphiphilic linker containing valeric acid and PEG performed worse than either linker type alone, at ˜30% functionality. We conclude that our previous 100% functional TCO result obtained with the two-step coupling may have stemmed from generation of the DBCO/azide cycloaddition product. Future work will explore factors such as rigidity of linker structure, polarity, or charges.

A Hartree-Fock Application Using UPC++ and the New DArray Library

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ozog, David; Kamil, Amir; Zheng, Yili

The Hartree-Fock (HF) method is the fundamental first step for incorporating quantum mechanics into many-electron simulations of atoms and molecules, and it is an important component of computational chemistry toolkits like NWChem. The GTFock code is an HF implementation that, while it does not have all the features in NWChem, represents crucial algorithmic advances that reduce communication and improve load balance by doing an up-front static partitioning of tasks, followed by work stealing whenever necessary. To enable innovations in algorithms and exploit next generation exascale systems, it is crucial to support quantum chemistry codes using expressive and convenient programming modelsmore » and runtime systems that are also efficient and scalable. Here, this paper presents an HF implementation similar to GTFock using UPC++, a partitioned global address space model that includes flexible communication, asynchronous remote computation, and a powerful multidimensional array library. UPC++ offers runtime features that are useful for HF such as active messages, a rich calculus for array operations, hardware-supported fetch-and-add, and functions for ensuring asynchronous runtime progress. We present a new distributed array abstraction, DArray, that is convenient for the kinds of random-access array updates and linear algebra operations on block-distributed arrays with irregular data ownership. Finally, we analyze the performance of atomic fetch-and-add operations (relevant for load balancing) and runtime attentiveness, then compare various techniques and optimizations for each. Our optimized implementation of HF using UPC++ and the DArrays library shows up to 20% improvement over GTFock with Global Arrays at scales up to 24,000 cores.« less

pH-regulated chemical oscillators.

PubMed

Orbán, Miklós; Kurin-Csörgei, Krisztina; Epstein, Irving R

2015-03-17

The hydrogen ion is arguably the most ubiquitous and important species in chemistry. It also plays a key role in nearly every biological process. In this Account, we discuss systems whose behavior is governed by oscillations in the concentration of hydrogen ion. The first chemical oscillators driven by changes in pH were developed a quarter century ago. Since then, about two dozen new pH oscillators, systems in which the periodic variation in pH is not just an indicator but an essential prerequisite of the oscillatory behavior, have been discovered. Mechanistic understanding of their behavior has grown, and new ideas for their practical application have been proposed and, in some cases, tested. Here we present a catalog of the known pH oscillators, divide them into mechanistically based categories based on whether they involve a single oxidant and reductant or an oxidant and a pair of reductants, and describe general mechanisms for these two major classes of systems. We also describe in detail the chemistry of one example from each class, hydrogen peroxide-sulfide and ferricyanide-iodate-sulfite. Finally, we consider actual and potential applications. These include using pH oscillators to induce oscillation in species that would otherwise be nonoscillatory, creating novel spatial patterns, generating periodic transitions between vesicle and micelle states, stimulating switching between folded and random coil states of DNA, building molecular motors, and designing pulsating drug delivery systems. We point out the importance for future applications of finding a batch pH oscillator, one that oscillates in a closed system for an extended period of time, and comment on the progress that has been made toward that goal.

Ablator Response Model Development: From Flight Data Back to Fundamental Experiments

NASA Technical Reports Server (NTRS)

Mansour, Nagi N.; Lachaud, Jean R.

2013-01-01

The successful Mars atmospheric entry by the Mars Science Laboratory (MSL-Curiosity) combined with the success of the Earth atmospheric entry by the Stardust capsule have established PICA as a major Thermal Protection Systems (TPS) material. We expect that this class of materials will be on the short list selected by NASA for any atmospheric entry missions and that it will be the lead of that list of materials in any planning, feasibility studies or flight readiness studies. In addition to NASAs successes, the Dragon capsule, the successful commercial space vehicle built by SpaceX, uses PICA-X, while the European Space Agency is considering ASTERM for its exploration missions that involve atmospheric entries, both of these materials are of the same family as PICA. In the talk, a high-fidelity model will be detailed and discussed. The model tracks the chemical composition of the gases produced during pyrolysis. As in the conventional models, it uses equilibrium chemistry to determine the recession rate at high temperatures but switches to in-volume finite-rate ablation for lower temperatures. It also tracks the time evolution of the porosity of the material. Progress in implementing this high-fidelity model in a code will be presented. In addition, a set of basic experimental data being supported for model validation will be summarized. The validation process for the model development will be discussed. Preliminary results will be presented for a case where detailed pyrolysis product chemistry is computed. Finally, a wish list for a set of validation experiments will be outlined and discussed.

Overcoming heterologous protein interdependency to optimize P450-mediated Taxol precursor synthesis in Escherichia coli

PubMed Central

Biggs, Bradley Walters; Lim, Chin Giaw; Sagliani, Kristen; Shankar, Smriti; Stephanopoulos, Gregory; Ajikumar, Parayil Kumaran

2016-01-01

Recent advances in metabolic engineering have demonstrated the potential to exploit biological chemistry for the synthesis of complex molecules. Much of the progress to date has leveraged increasingly precise genetic tools to control the transcription and translation of enzymes for superior biosynthetic pathway performance. However, applying these approaches and principles to the synthesis of more complex natural products will require a new set of tools for enabling various classes of metabolic chemistries (i.e., cyclization, oxygenation, glycosylation, and halogenation) in vivo. Of these diverse chemistries, oxygenation is one of the most challenging and pivotal for the synthesis of complex natural products. Here, using Taxol as a model system, we use nature’s favored oxygenase, the cytochrome P450, to perform high-level oxygenation chemistry in Escherichia coli. An unexpected coupling of P450 expression and the expression of upstream pathway enzymes was discovered and identified as a key obstacle for functional oxidative chemistry. By optimizing P450 expression, reductase partner interactions, and N-terminal modifications, we achieved the highest reported titer of oxygenated taxanes (∼570 ± 45 mg/L) in E. coli. Altogether, this study establishes E. coli as a tractable host for P450 chemistry, highlights the potential magnitude of protein interdependency in the context of synthetic biology and metabolic engineering, and points to a promising future for the microbial synthesis of complex chemical entities. PMID:26951651

Overcoming heterologous protein interdependency to optimize P450-mediated Taxol precursor synthesis in Escherichia coli.

PubMed

Biggs, Bradley Walters; Lim, Chin Giaw; Sagliani, Kristen; Shankar, Smriti; Stephanopoulos, Gregory; De Mey, Marjan; Ajikumar, Parayil Kumaran

2016-03-22

Recent advances in metabolic engineering have demonstrated the potential to exploit biological chemistry for the synthesis of complex molecules. Much of the progress to date has leveraged increasingly precise genetic tools to control the transcription and translation of enzymes for superior biosynthetic pathway performance. However, applying these approaches and principles to the synthesis of more complex natural products will require a new set of tools for enabling various classes of metabolic chemistries (i.e., cyclization, oxygenation, glycosylation, and halogenation) in vivo. Of these diverse chemistries, oxygenation is one of the most challenging and pivotal for the synthesis of complex natural products. Here, using Taxol as a model system, we use nature's favored oxygenase, the cytochrome P450, to perform high-level oxygenation chemistry in Escherichia coli. An unexpected coupling of P450 expression and the expression of upstream pathway enzymes was discovered and identified as a key obstacle for functional oxidative chemistry. By optimizing P450 expression, reductase partner interactions, and N-terminal modifications, we achieved the highest reported titer of oxygenated taxanes (∼570 ± 45 mg/L) in E. coli. Altogether, this study establishes E. coli as a tractable host for P450 chemistry, highlights the potential magnitude of protein interdependency in the context of synthetic biology and metabolic engineering, and points to a promising future for the microbial synthesis of complex chemical entities.

Let's Face(book) It: Analyzing Interactions in Social Network Groups for Chemistry Learning

NASA Astrophysics Data System (ADS)

Rap, Shelley; Blonder, Ron

2016-02-01

We examined how social network (SN) groups contribute to the learning of chemistry. The main goal was to determine whether chemistry learning could occur in the group discourse. The emphasis was on groups of students in the 11th and 12th grades who learn chemistry in preparation for their final external examination. A total of 1118 discourse events were tallied in the different groups. We analyzed the different events that were found in chemistry learning Facebook groups (CLFGs). The analysis revealed that seven types of interactions were observed in the CLFGs: The most common interaction (47 %) dealt with organizing learning (e.g., announcements regarding homework, the location of the next class); learning interactions were observed in 22 % of the posts, and links to learning materials and social interactions constituted about 20 % each. The learning events that were ascertained underwent a deeper examination and three different types of chemistry learning interactions were identified. This examination was based on the theoretical framework of the commognitive approach to learning (Sfard in Thinking as communicating. Cambridge University Press, Cambridge, 2008), which will be explained. The identified learning interactions that were observed in the Facebook groups illustrate the potential of SNs to serve as an additional tool for teachers to advance their students' learning of chemistry.

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

PubMed Central

2015-01-01

Summary The implementation of continuous flow processing as a key enabling technology has transformed the way we conduct chemistry and has expanded our synthetic capabilities. As a result many new preparative routes have been designed towards commercially relevant drug compounds achieving more efficient and reproducible manufacture. This review article aims to illustrate the holistic systems approach and diverse applications of flow chemistry to the preparation of pharmaceutically active molecules, demonstrating the value of this strategy towards every aspect ranging from synthesis, in-line analysis and purification to final formulation and tableting. Although this review will primarily concentrate on large scale continuous processing, additional selected syntheses using micro or meso-scaled flow reactors will be exemplified for key transformations and process control. It is hoped that the reader will gain an appreciation of the innovative technology and transformational nature that flow chemistry can leverage to an overall process. PMID:26425178

LOGICAL REASONING ABILITY AND STUDENT PERFORMANCE IN GENERAL CHEMISTRY.

PubMed

Bird, Lillian

2010-03-01

Logical reasoning skills of students enrolled in General Chemistry at the University of Puerto Rico in Río Piedras were measured using the Group Assessment of Logical Thinking (GALT) test. The results were used to determine the students' cognitive level (concrete, transitional, formal) as well as their level of performance by logical reasoning mode (mass/volume conservation, proportional reasoning, correlational reasoning, experimental variable control, probabilistic reasoning and combinatorial reasoning). This information was used to identify particular deficiencies and gender effects, and to determine which logical reasoning modes were the best predictors of student performance in the general chemistry course. Statistical tests to analyze the relation between (a) operational level and final grade in both semesters of the course; (b) GALT test results and performance in the ACS General Chemistry Examination; and (c) operational level and student approach (algorithmic or conceptual) towards a test question that may be answered correctly using either strategy, were also performed.

Light-emitting diodes for analytical chemistry.

PubMed

Macka, Mirek; Piasecki, Tomasz; Dasgupta, Purnendu K

2014-01-01

Light-emitting diodes (LEDs) are playing increasingly important roles in analytical chemistry, from the final analysis stage to photoreactors for analyte conversion to actual fabrication of and incorporation in microdevices for analytical use. The extremely fast turn-on/off rates of LEDs have made possible simple approaches to fluorescence lifetime measurement. Although they are increasingly being used as detectors, their wavelength selectivity as detectors has rarely been exploited. From their first proposed use for absorbance measurement in 1970, LEDs have been used in analytical chemistry in too many ways to make a comprehensive review possible. Hence, we critically review here the more recent literature on their use in optical detection and measurement systems. Cloudy as our crystal ball may be, we express our views on the future applications of LEDs in analytical chemistry: The horizon will certainly become wider as LEDs in the deep UV with sufficient intensity become available.

Barriers to the implementation of green chemistry in the United States.

PubMed

Matus, Kira J M; Clark, William C; Anastas, Paul T; Zimmerman, Julie B

2012-10-16

This paper investigates the conditions under which firms are able to develop and implement innovations with sustainable development benefits. In particular, we examine "green chemistry" innovations in the United States. Via interviews with green chemistry leaders from industry, academia, nongovernmental institutions (NGOs), and government, we identified six major categories of challenges commonly confronted by innovators: (1) economic and financial, (2) regulatory, (3) technical, (4) organizational, (5) cultural, and (6) definition and metrics. Further analysis of these barriers shows that in the United States, two elements of these that are particular to the implementation of green chemistry innovations are the absence of clear definitions and metrics for use by researchers and decision makers, as well as the interdisciplinary demands of these innovations on researchers and management. Finally, we conclude with some of the strategies that have been successful thus far in overcoming these barriers, and the types of policies which could have positive impacts moving forward.

The Connection between Success in a Freshman Chemistry Class and a Student's Jungian Personality Type

NASA Astrophysics Data System (ADS)

Clark, Gale J.; Riley, Wayne D.

2001-10-01

This paper explores the connection between a student's performance in a freshman chemistry class and his or her personality type. Performance was gauged by the final percentage grade earned in class and personality type was based on Carl G. Jung's personality typology as assessed by the Myers-Briggs Type Indicator (MBTI). Performance and personality type were correlated using ANOVA statistics. The results show that only one of the 16 personality types had a class average that was significantly higher than 14 of the other 15 types. The lowest-scoring type was also significantly lower than 3 other personality types. This research shows that characteristics of personality types may be a basis for assisting or deterring success in a general chemistry class. Data on the personality types of 23 chemistry professors suggest that a success bias may be amplified by similar personality traits in the instructors.

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry.

PubMed

Baumann, Marcus; Baxendale, Ian R

2015-01-01

The implementation of continuous flow processing as a key enabling technology has transformed the way we conduct chemistry and has expanded our synthetic capabilities. As a result many new preparative routes have been designed towards commercially relevant drug compounds achieving more efficient and reproducible manufacture. This review article aims to illustrate the holistic systems approach and diverse applications of flow chemistry to the preparation of pharmaceutically active molecules, demonstrating the value of this strategy towards every aspect ranging from synthesis, in-line analysis and purification to final formulation and tableting. Although this review will primarily concentrate on large scale continuous processing, additional selected syntheses using micro or meso-scaled flow reactors will be exemplified for key transformations and process control. It is hoped that the reader will gain an appreciation of the innovative technology and transformational nature that flow chemistry can leverage to an overall process.

LOGICAL REASONING ABILITY AND STUDENT PERFORMANCE IN GENERAL CHEMISTRY

PubMed Central

Bird, Lillian

2010-01-01

Logical reasoning skills of students enrolled in General Chemistry at the University of Puerto Rico in Río Piedras were measured using the Group Assessment of Logical Thinking (GALT) test. The results were used to determine the students’ cognitive level (concrete, transitional, formal) as well as their level of performance by logical reasoning mode (mass/volume conservation, proportional reasoning, correlational reasoning, experimental variable control, probabilistic reasoning and combinatorial reasoning). This information was used to identify particular deficiencies and gender effects, and to determine which logical reasoning modes were the best predictors of student performance in the general chemistry course. Statistical tests to analyze the relation between (a) operational level and final grade in both semesters of the course; (b) GALT test results and performance in the ACS General Chemistry Examination; and (c) operational level and student approach (algorithmic or conceptual) towards a test question that may be answered correctly using either strategy, were also performed. PMID:21373364

The State of Organic Teaching Laboratories

ERIC Educational Resources Information Center

Horowitz, Gail

2007-01-01

The changes that have taken place in the organic chemistry laboratory course since 1980s are reviewed with reference to the quantity and diversity of discovery-based experiments available to date. The data illustrates that significant progress is towards accomplishing dramatic changes such as the almost universal adoption of microscale, the use of…

Fulldome Video: An Emerging Technology for Education

ERIC Educational Resources Information Center

Law, Linda E.

2006-01-01

This article talks about fulldome video, a new technology which has been adopted fairly extensively by the larger, well-funded planetariums. Fulldome video, also called immersive projection, can help teach subjects ranging from geology to history to chemistry. The rapidly advancing progress of projection technology has provided high-resolution…

Towards the Next Generation Air Quality Modeling System: Current Progress on Implementing Chemistry into MPAS-A

EPA Science Inventory

The community multiscale air quality (CMAQ) model of the U.S. Environmental Protection Agency is one of the most widely used air quality model worldwide; it is employed for both research and regulatory applications at major universities and government agencies for improving under...

Analytical chemistry of PCBs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erickson, M.D.

Analytical Chemistry of PCBs offers a review of physical, chemical, commercial, environmental and biological properties of PCBs. It also defines and discusses six discrete steps of analysis: sampling, extraction, cleanup, determination, data reduction, and quality assurance. The final chapter provides a discussion on collaborative testing - the ultimate step in method evaluation. Dr. Erickson also provides a bibliography of over 1200 references, critical reviews of primary literature, and five appendices which present ancillary material on PCB nomen-clature, physical properties, composition of commercial mixtures, mass spectra characteristics, and PGC/ECD chromatograms.

Collaborative Research: Atmospheric Pressure Microplasma Chemistry-Photon Synergies Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Graves, David

Combining the effects of low temperature, atmospheric pressure microplasmas and microplasma photon sources shows greatly expanded range of applications of each of them. The plasma sources create active chemical species and these can be activated further by addition of photons and associated photochemistry. There are many ways to combine the effects of plasma chemistry and photochemistry, especially if there are multiple phases present. The project combines construction of appropriate test experimental systems, various spectroscopic diagnostics and mathematical modeling.

Recent progress on DNA based walkers.

PubMed

Pan, Jing; Li, Feiran; Cha, Tae-Gon; Chen, Haorong; Choi, Jong Hyun

2015-08-01

DNA based synthetic molecular walkers are reminiscent of biological protein motors. They are powered by hybridization with fuel strands, environment induced conformational transitions, and covalent chemistry of oligonucleotides. Recent developments in experimental techniques enable direct observation of individual walkers with high temporal and spatial resolution. The functionalities of state-of-the-art DNA walker systems can thus be analyzed for various applications. Herein we review recent progress on DNA walker principles and characterization methods, and evaluate various aspects of their functions for future applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

Research progress of microbial corrosion of reinforced concrete structure

NASA Astrophysics Data System (ADS)

Li, Shengli; Li, Dawang; Jiang, Nan; Wang, Dongwei

2011-04-01

Microbial corrosion of reinforce concrete structure is a new branch of learning. This branch deals with civil engineering , environment engineering, biology, chemistry, materials science and so on and is a interdisciplinary area. Research progress of the causes, research methods and contents of microbial corrosion of reinforced concrete structure is described. The research in the field is just beginning and concerted effort is needed to go further into the mechanism of reinforce concrete structure and assess the security and natural life of reinforce concrete structure under the special condition and put forward the protective methods.

Our Everyday Cup of Coffee: The Chemistry behind Its Magic

NASA Astrophysics Data System (ADS)

Petracco, Marino

2005-08-01

Coffee beverages are so popular all over the world that there is hardly any need to describe them. But underlying this seemingly commonplace beverage there is a whole realm worth serious scientific study. The complexity of the raw seed matrix, made even more intricate when roasted, requires a deep understanding of its chemical nature. While coffee is not consumed for nutritional purposes, it is appreciated for its taste appeal along with its stimulating effects on mental and physical activity. The attention to quality is of paramount importance to both of these aspects to supply the customers with a pleasant and wholesome product. The chemical approach to the sensory sphere has seen the development of increasingly sophisticated analytical methods where the parts per billion of volatile aromas are not the ultimate frontier of detection limits. In spite of the progress of instrumental techniques, the cup-testing approach still remains the final assessment tool to obtain the approval for choosing the right plant and for conveying the product to the market. This is even truer when espresso, the fashionable type of coffee brewing methods, is considered.

Recent Advances in Multi-component Particles Assembly.

PubMed

Guo, Dan; Song, Yanlin

2018-03-09

Particles assembly and co-assembly have been research frontiers in chemistry and material science in the past few decades. To achieve a large variety of intricate structures and functional materials, remarkable progress has been made in the particle assembly principles and strategies. It can be summarized that the particle assembly is driven by intrinsic interparticle interaction or the external control. In this article, we focus on binary or ternary particles co-assembly and review the principles and feasible strategies. These advances have led to new disciplines of microfabrication technology and material engineering. Although remarked achievement on particle-based structures has been made, it is still challenging to fully develop general and facile strategies to precisely control the one-dimensional (1D) co-assembly. This article reviews the recent development on multi-component particles co-assembly, which significantly increases structural complexity and functional diversity. In particular, we highlight the advances in the particles co-assembly of well-ordered 1D binary superstructures by liquid soft confinement. Finally, prospective outlook for future trends in this field is proposed. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

THMC Modeling of EGS Reservoirs -- Continuum through Discontinuum Representations. Capturing Reservoir Stimulation, Evolution and Induced Seismicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elsworth, Derek; Izadi, Ghazal; Gan, Quan

This work has investigated the roles of effective stress induced by changes in fluid pressure, temperature and chemistry in contributing to the evolution of permeability and induced seismicity in geothermal reservoirs. This work has developed continuum models [1] to represent the progress or seismicity during both stimulation [2] and production [3]. These methods have been used to resolve anomalous observations of induced seismicity at the Newberry Volcano demonstration project [4] through the application of modeling and experimentation. Later work then focuses on the occurrence of late stage seismicity induced by thermal stresses [5] including the codifying of the timing andmore » severity of such responses [6]. Furthermore, mechanistic linkages between observed seismicity and the evolution of permeability have been developed using data from the Newberry project [7] and benchmarked against field injection experiments. Finally, discontinuum models [8] incorporating the roles of discrete fracture networks have been applied to represent stimulation and then thermal recovery for new arrangements of geothermal wells incorporating the development of flow manifolds [9] in order to increase thermal output and longevity in EGS systems.« less

Quarterly Progress Report (January 1 to March 31, 1950)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brookhaven National Laboratory

This is the first of a series of Quarterly Reports. These reports will deal primarily with the progress made in our scientific program during a three months period. Those interested in matters pertaining to organization, administration, complete scientific program, personnel and other matters not directly involved in current scientific progress are referred to our Annual Progress Report which is issued in January. We have attempted to describe new information that appears significant, or of interest, to other scientists within the Atomic Energy Commission Laboratories. No effort has been made, however, to detail progress in each and every research project. Littlemore » or no reference will therefore be found to the projects in which progress during the current period is considered too inconclusive. Since our organizational structure is departmental, the work described herein is arranged in the following sequence: (1) Accelerator Project; (2) Biology Department; (3) Chemistry Department; (4) Instrumentation and Health Physic8 Department; (5) Medical Department; (6) Physics Department; and (7) Reactor Science and Engineering Department.« less

46 CFR 172.195 - Survival conditions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... assumed damage if it meets the following conditions in the final stage of flooding: (a) Final waterline... of an opening through which progressive flooding may take place, such as an air pipe, or an opening... least 3.94 inches (10 cm). (3) Each submerged opening must be weathertight. (d) Progressive flooding. If...

46 CFR 172.195 - Survival conditions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... assumed damage if it meets the following conditions in the final stage of flooding: (a) Final waterline... of an opening through which progressive flooding may take place, such as an air pipe, or an opening... least 3.94 inches (10 cm). (3) Each submerged opening must be weathertight. (d) Progressive flooding. If...

46 CFR 172.195 - Survival conditions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... assumed damage if it meets the following conditions in the final stage of flooding: (a) Final waterline... of an opening through which progressive flooding may take place, such as an air pipe, or an opening... least 3.94 inches (10 cm). (3) Each submerged opening must be weathertight. (d) Progressive flooding. If...

Final Report - Low Temperature Combustion Chemistry And Fuel Component Interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wooldridge, Margaret

Recent research into combustion chemistry has shown that reactions at “low temperatures” (700 – 1100 K) have a dramatic influence on ignition and combustion of fuels in virtually every practical combustion system. A powerful class of laboratory-scale experimental facilities that can focus on fuel chemistry in this temperature range is the rapid compression facility (RCF), which has proven to be a versatile tool to examine the details of fuel chemistry in this important regime. An RCF was used in this project to advance our understanding of low temperature chemistry of important fuel compounds. We show how factors including fuel molecularmore » structure, the presence of unsaturated C=C bonds, and the presence of alkyl ester groups influence fuel auto-ignition and produce variable amounts of negative temperature coefficient behavior of fuel ignition. We report new discoveries of synergistic ignition interactions between alkane and alcohol fuels, with both experimental and kinetic modeling studies of these complex interactions. The results of this project quantify the effects of molecular structure on combustion chemistry including carbon bond saturation, through low temperature experimental studies of esters, alkanes, alkenes, and alcohols.« less

Correlation of Preadmission Organic Chemistry Courses and Academic Performance in Biochemistry at a Midwest Chiropractic Doctoral Program*

PubMed Central

McRae, Marc P.

2010-01-01

Purpose: Organic chemistry has been shown to correlate with academic success in the preclinical years of medicine, dentistry, and graduate physiology. The purpose of this study is to examine the relationship between undergraduate organic chemistry grades and first-semester biochemistry grades at a Midwest chiropractic doctoral program. Methods: Students enrolled in a first-semester biochemistry course who had completed the prerequisite courses in organic chemistry offered at this same institution were entered into the study. The total grade for each of the three courses was calculated using the midterm and final exam raw scores with a weighting of 50% each. Analysis consisted of obtaining correlation coefficients between the total grades of organic 1 with biochemistry and organic 2 with biochemistry. Using the biochemistry total grade, the students were divided into quartiles and course grades for both organic chemistry 1 and 2 were calculated. Results: For the 109 students in the study, the correlation coefficient between the biochemistry and organic chemistry 1 and biochemistry and organic chemistry 2 courses was r = 0.744 and r = 0.725, respectively. The difference in organic chemistry grades between those in the first and fourth quartiles was 63.2% and 86.9% for organic chemistry 1 (p < .001) and 60.9% and 79.4% for organic chemistry 2 (p < .001). Conclusion: This study shows that organic chemistry can be used as an indicator of future academic success in a chiropractic biochemistry course. Knowledge of such a relationship could prove useful to identify students who may potentially run into academic difficulty with first-year biochemistry PMID:20480012

Assessment of Application Technology of Natural User Interfaces in the Creation of a Virtual Chemical Laboratory

NASA Astrophysics Data System (ADS)

Jagodziński, Piotr; Wolski, Robert

2015-02-01

Natural User Interfaces (NUI) are now widely used in electronic devices such as smartphones, tablets and gaming consoles. We have tried to apply this technology in the teaching of chemistry in middle school and high school. A virtual chemical laboratory was developed in which students can simulate the performance of laboratory activities similar to those that they perform in a real laboratory. Kinect sensor was used for the detection and analysis of the student's hand movements, which is an example of NUI. The studies conducted found the effectiveness of educational virtual laboratory. The extent to which the use of a teaching aid increased the students' progress in learning chemistry was examined. The results indicate that the use of NUI creates opportunities to both enhance and improve the quality of the chemistry education. Working in a virtual laboratory using the Kinect interface results in greater emotional involvement and an increased sense of self-efficacy in the laboratory work among students. As a consequence, students are getting higher marks and are more interested in the subject of chemistry.

On the outside looking in: redefining the role of analytical chemistry in the biosciences.

PubMed

Hare, Dominic J; New, Elizabeth J

2016-07-12

Biomedical research has moved on from the study of the structure of organs, cells and organelles. Today, the key questions that must be addressed to understand the body in health and disease are related to fundamental biochemistry: the distribution and speciation of chemicals, the regulation of chemical reactions, and the control of chemical environments. To see advances in this field, it is essential for analytical chemists to actively engage in this process, from beginning to end. In this Feature Article, we review the progress that has been made towards gaining an understanding of the chemistry of the body, while commenting on the intrinsic disconnect between new innovations in the field of analytical chemistry and practical application within the biosciences. We identify the challenges that prevent chemists from making a greater impact in this field, and highlight key steps for moving forward.

Analytical Chemistry in the Regulatory Science of Medical Devices.

PubMed

Wang, Yi; Guan, Allan; Wickramasekara, Samanthi; Phillips, K Scott

2018-06-12

In the United States, regulatory science is the science of developing new tools, standards, and approaches to assess the safety, efficacy, quality, and performance of all Food and Drug Administration-regulated products. Good regulatory science facilitates consumer access to innovative medical devices that are safe and effective throughout the Total Product Life Cycle (TPLC). Because the need to measure things is fundamental to the regulatory science of medical devices, analytical chemistry plays an important role, contributing to medical device technology in two ways: It can be an integral part of an innovative medical device (e.g., diagnostic devices), and it can be used to support medical device development throughout the TPLC. In this review, we focus on analytical chemistry as a tool for the regulatory science of medical devices. We highlight recent progress in companion diagnostics, medical devices on chips for preclinical testing, mass spectrometry for postmarket monitoring, and detection/characterization of bacterial biofilm to prevent infections.

Computational chemistry for NH 3 synthesis, hydrotreating, and NO x reduction: Three topics of special interest to Haldor Topsøe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elnabawy, Ahmed O.; Rangarajan, Srinivas; Mavrikakis, Manos

Computational chemistry, especially density functional theory, has experienced a remarkable growth in terms of application over the last few decades. This is attributed to the improvements in theory and computing infrastructure that enable the analysis of systems of unprecedented size and detail at an affordable computational expense. In this perspective, we discuss recent progress and current challenges facing electronic structure theory in the context of heterogeneous catalysis. We specifically focus on the impact of computational chemistry in elucidating and designing catalytic systems in three topics of interest to Haldor Topsøe – ammonia, synthesis, hydrotreating, and NO x reduction. Furthermore, wemore » then discuss the common tools and concepts in computational catalysis that underline these topics and provide a perspective on the challenges and future directions of research in this area of catalysis research.« less

Quarterly progress report for the Chemical and Energy Research Section of the Chemical Technology Division: July--September 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jubin, R.T.

This report summarizes the major activities conducted in the Chemical and Energy Research Section of the Chemical Technology Division at Oak Ridge National Laboratory (ORNL) during the period July--September 1997. The section conducts basic and applied research and development in chemical engineering, applied chemistry, and bioprocessing, with an emphasis on energy-driven technologies and advanced chemical separations for nuclear and waste applications. The report describes the various tasks performed within nine major areas of research: Hot Cell Operations, Process Chemistry and Thermodynamics, Molten Salt Reactor Experiment (MSRE) Remediation Studies, Chemistry Research, Biotechnology, Separations and Materials Synthesis, Fluid Structure and Properties, Biotechnologymore » Research, and Molecular Studies. The name of a technical contact is included with each task described, and readers are encouraged to contact these individuals if they need additional information.« less

Computational chemistry for NH 3 synthesis, hydrotreating, and NO x reduction: Three topics of special interest to Haldor Topsøe

DOE PAGES

Elnabawy, Ahmed O.; Rangarajan, Srinivas; Mavrikakis, Manos

2015-06-05

Computational chemistry, especially density functional theory, has experienced a remarkable growth in terms of application over the last few decades. This is attributed to the improvements in theory and computing infrastructure that enable the analysis of systems of unprecedented size and detail at an affordable computational expense. In this perspective, we discuss recent progress and current challenges facing electronic structure theory in the context of heterogeneous catalysis. We specifically focus on the impact of computational chemistry in elucidating and designing catalytic systems in three topics of interest to Haldor Topsøe – ammonia, synthesis, hydrotreating, and NO x reduction. Furthermore, wemore » then discuss the common tools and concepts in computational catalysis that underline these topics and provide a perspective on the challenges and future directions of research in this area of catalysis research.« less

All-inorganic Germanium nanocrystal films by cationic ligand exchange

DOE PAGES

Wheeler, Lance M.; Nichols, Asa W.; Chernomordik, Boris D.; ...

2016-01-21

In this study, we introduce a new paradigm for group IV nanocrystal surface chemistry based on room temperature surface activation that enables ionic ligand exchange. Germanium nanocrystals synthesized in a gas-phase plasma reactor are functionalized with labile, cationic alkylammonium ligands rather than with traditional covalently bound groups. We employ Fourier transform infrared and 1H nuclear magnetic resonance spectroscopies to demonstrate the alkylammonium ligands are freely exchanged on the germanium nanocrystal surface with a variety of cationic ligands, including short inorganic ligands such as ammonium and alkali metal cations. This ionic ligand exchange chemistry is used to demonstrate enhanced transport inmore » germanium nanocrystal films following ligand exchange as well as the first photovoltaic device based on an all-inorganic germanium nanocrystal absorber layer cast from solution. This new ligand chemistry should accelerate progress in utilizing germanium and other group IV nanocrystals for optoelectronic applications.« less

Carbon chemistry of circumstellar envelopes

NASA Technical Reports Server (NTRS)

Bieging, John H.

1990-01-01

The chemical composition of envelopes surrounding cool evolved stars, as determined from microwave spectroscopic observations, is reviewed. Emphasis is placed on recent observations with the new large mm-wavelength telescopes and interferometer arrays, and on new theoretical work, especially concerning ion-molecule chemistry of carbon-bearing in these envelopes. Thermal (as opposed to maser) emission lines are discussed. Much progress has been made in the past few years in the theoretical understanding of these objects. It is already clear, however, that observations with the new generation of mm-telescopes will require substantial improvements in the theoretical models to achieve a thorough understanding of the data now becoming available.

The Chemical Biology of HNO Signaling

PubMed Central

Bianco, Christopher L.; Toscano, John P.; Bartberger, Michael D.; Fukuto, Jon M.

2016-01-01

Nitroxyl (HNO) is a simple molecule with significant potential as a pharmacological agent. For example, its use in the possible treatment of heart failure has received recent attention due to its unique therapeutic properties. Recent progress has been made on the elucidation of the mechanisms associated with its biological signaling. Importantly, the biochemical mechanisms described for HNO bioactivity are consistent with its unique and novel chemical properties/reactivity. To date, much of the biology of HNO can be associated with interactions and modification of important regulatory thiol proteins. Herein will be provided a description of HNO chemistry and how this chemistry translates to some of its reported biological effects. PMID:27555493

Chemical Structures and Bioactivities of Sulfated Polysaccharides from Marine Algae

PubMed Central

Jiao, Guangling; Yu, Guangli; Zhang, Junzeng; Ewart, H. Stephen

2011-01-01

Sulfated polysaccharides and their lower molecular weight oligosaccharide derivatives from marine macroalgae have been shown to possess a variety of biological activities. The present paper will review the recent progress in research on the structural chemistry and the bioactivities of these marine algal biomaterials. In particular, it will provide an update on the structural chemistry of the major sulfated polysaccharides synthesized by seaweeds including the galactans (e.g., agarans and carrageenans), ulvans, and fucans. It will then review the recent findings on the anticoagulant/antithrombotic, antiviral, immuno-inflammatory, antilipidemic and antioxidant activities of sulfated polysaccharides and their potential for therapeutic application. PMID:21566795

A Rotaxane Scaffold for the Construction of Multiporphyrinic Light-Harvesting Devices.

PubMed

Delavaux-Nicot, Béatrice; Ben Aziza, Haifa; Nierengarten, Iwona; Minh Nguyet Trinh, Thi; Meichsner, Eric; Chessé, Matthieu; Holler, Michel; Abidi, Rym; Maisonhaute, Emmanuel; Nierengarten, Jean-François

2018-01-02

A sophisticated photoactive molecular device has been prepared by combining recent concepts for the preparation of multifunctional nanomolecules (click chemistry on multifunctional scaffolds) with supramolecular chemistry (self-assembly to prepare rotaxanes). Specifically, a clickable [2]rotaxane scaffold incorporating a free-base porphyrin stopper has been prepared and functionalized with ten peripheral Zn(II)-porphyrin moieties. Electrochemical investigations of the final compound revealed a peculiar behavior resulting from the intramolecular coordination of the Zn(II) porphyrin moieties to 1,2,3-triazole units. Finally, steady state investigations of the compound combining Zn(II) and free-base porphyrin moieties have shown that this compound is a light-harvesting device capable of channeling the light energy from the peripheral Zn(II)-porphyrin subunits to the core by singlet-singlet energy transfer. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determining association constants from titration experiments in supramolecular chemistry.

PubMed

Thordarson, Pall

2011-03-01

The most common approach for quantifying interactions in supramolecular chemistry is a titration of the guest to solution of the host, noting the changes in some physical property through NMR, UV-Vis, fluorescence or other techniques. Despite the apparent simplicity of this approach, there are several issues that need to be carefully addressed to ensure that the final results are reliable. This includes the use of non-linear rather than linear regression methods, careful choice of stoichiometric binding model, the choice of method (e.g., NMR vs. UV-Vis) and concentration of host, the application of advanced data analysis methods such as global analysis and finally the estimation of uncertainties and confidence intervals for the results obtained. This tutorial review will give a systematic overview of all these issues-highlighting some of the key messages herein with simulated data analysis examples.

Overview of the ISOL facility for the RISP

NASA Astrophysics Data System (ADS)

Woo, H. J.; Kang, B. H.; Tshoo, K.; Seo, C. S.; Hwang, W.; Park, Y.-H.; Yoon, J. W.; Yoo, S. H.; Kim, Y. K.; Jang, D. Y.

2015-02-01

The key feature of the Isotope Separation On-Line (ISOL) facility is its ability to provide high-intensity and high-quality beams of neutron-rich isotopes with masses in the range of 80-160 by means of a 70-MeV proton beam directly impinging on uranium-carbide thin-disc targets to perform forefront research in nuclear structure, nuclear astrophysics, reaction dynamics and interdisciplinary fields like medical, biological and material sciences. The technical design of the 10-kW and the 35-kW direct fission targets with in-target fission rates of up to 1014 fissions/s has been finished, and for the development of the ISOL fission-target chemistry an initial effort has been made to produce porous lanthanum-carbide (LaCx) discs as a benchmark for the final production of porous UCx discs. For the production of various beams, three classes of ion sources are under development at RISP (Rare Isotope Science Project), the surface ion source, the plasma ion source (FEBIAD), the laser ion source, and the engineering design of the FEBIAD is in progress for prototype fabrication. The engineering design of the ISOL target/ion source front-end system is also in progress, and a prototype will be used for an off-line test facility in front of the pre-separator. The technical designs of other basic elements at the ISOL facility, such as the RF-cooler, the high-resolution mass separator, and the A/q separator, have been finished, and the results, along with the future plans, are introduced.

Inkjet printing for biosensor fabrication: combining chemistry and technology for advanced manufacturing.

PubMed

Li, Jia; Rossignol, Fabrice; Macdonald, Joanne

2015-06-21

Inkjet printing is emerging at the forefront of biosensor fabrication technologies. Parallel advances in both ink chemistry and printers have led to a biosensor manufacturing approach that is simple, rapid, flexible, high resolution, low cost, efficient for mass production, and extends the capabilities of devices beyond other manufacturing technologies. Here we review for the first time the factors behind successful inkjet biosensor fabrication, including printers, inks, patterning methods, and matrix types. We discuss technical considerations that are important when moving beyond theoretical knowledge to practical implementation. We also highlight significant advances in biosensor functionality that have been realised through inkjet printing. Finally, we consider future possibilities for biosensors enabled by this novel combination of chemistry and technology.

An Overview of Atmospheric Chemistry and Air Quality Modeling

NASA Technical Reports Server (NTRS)

Johnson, Matthew S.

2017-01-01

This presentation will include my personal research experience and an overview of atmospheric chemistry and air quality modeling to the participants of the NASA Student Airborne Research Program (SARP 2017). The presentation will also provide examples on ways to apply airborne observations for chemical transport (CTM) and air quality (AQ) model evaluation. CTM and AQ models are important tools in understanding tropospheric-stratospheric composition, atmospheric chemistry processes, meteorology, and air quality. This presentation will focus on how NASA scientist currently apply CTM and AQ models to better understand these topics. Finally, the importance of airborne observation in evaluating these topics and how in situ and remote sensing observations can be used to evaluate and improve CTM and AQ model predictions will be highlighted.

College Chemistry and Piaget: An Analysis of Gender Difference, Cognitive Abilities, and Achievement Measures Seventeen Years Apart

NASA Astrophysics Data System (ADS)

Shibley, Ivan A., Jr.; Milakofsky, Louis M.; Bender, David S.; Patterson, Henry O.

2003-05-01

This study revisits an analysis of gender difference in the cognitive abilities of college chemistry students using scores from "Inventory of Piaget's Developmental Tasks" (IPDT), the Scholastic Assessment Test (SAT), and final grades from an introductory college chemistry course. Comparison of 1998 scores with those from 1981 showed an overall decline on most of the measures and a changing pattern among males and females. Gender differences were found in the IPDT subtests measuring imagery, classification, and proportional reasoning, but not conservation, a pattern that differs from the findings reported 17 years earlier. The generational and gender differences revealed in this study suggest that instructors should be cognizant of, and should periodically assess, the diversity of students' cognitive abilities.

Factors related to achievement in sophomore organic chemistry at the University of Arkansas

NASA Astrophysics Data System (ADS)

Lindsay, Harriet Arlene

The purpose of this study was to identify the significant cognitive and non-cognitive variables that related to achievement in the first semester of organic chemistry at the University of Arkansas. Cognitive variables included second semester general chemistry grade, ACT composite score, ACT English, mathematics, reading, and science reasoning subscores, and spatial ability. Non-cognitive variables included anxiety, confidence, effectance motivation, and usefulness. Using a correlation research design, the individual relationships between organic chemistry achievement and each of the cognitive variables and non-cognitive variables were assessed. In addition, the relationships between organic chemistry achievement and combinations of these independent variables were explored. Finally, gender- and instructor-related differences in the relationships between organic chemistry achievement and the independent variables were investigated. The samples consisted of volunteers from the Fall 1999 and Fall 2000 sections of Organic Chemistry I at the University of Arkansas. All students in each section were asked to participate. Data for spatial ability and non-cognitive independent variables were collected using the Purdue Visualization of Rotations test and the modified Fennema-Sherman Attitude Scales. Data for other independent variables, including ACT scores and second semester general chemistry grades, were obtained from the Office of Institutional Research. The dependent variable, organic chemistry achievement, was measured by each student's accumulated points in the course and consisted of scores on quizzes and exams in the lecture section only. These totals were obtained from the lecture instructor at the end of each semester. Pearson correlation and stepwise multiple regression analyses were used to measure the relationships between organic chemistry achievement and the independent variables. Prior performance in chemistry as measured by second semester general chemistry grade was the best indicator of performance in organic chemistry. The importance of other independent variables in explaining organic chemistry achievement varied between instructors. In addition, gender differences were found in the explanations of organic chemistry achievement variance provided by this study. In general, males exhibited stronger correlations between independent variables and organic chemistry achievement than females. The report contains 19 tables detailing the statistical analyses. Suggestions for improved practice and further research are also included

Exhaust Gas Emissions from a Rotating Detonation-wave Engine

NASA Astrophysics Data System (ADS)

Kailasanath, Kazhikathra; Schwer, Douglas

2015-11-01

Rotating detonation-wave engines (RDE) are a form of continuous detonation-wave engines. They potentially provide further gains in performance than an intermittent or pulsed detonation-wave engine (PDE). The overall flow field in an idealized RDE, primarily consisting of two concentric cylinders, has been discussed in previous meetings. Because of the high pressures involved and the lack of adequate reaction mechanisms for this regime, previous simulations have typically used simplified chemistry models. However, understanding the exhaust species concentrations in propulsion devices is important for both performance considerations as well as estimating pollutant emissions. Progress towards addressing this need will be discussed in this talk. In this approach, an induction parameter model is used for simulating the detonation but a more detailed finite-chemistry model including NOx chemistry is used in the expansion flow region, where the pressures are lower and the uncertainties in the chemistry model are greatly reduced. Results show that overall radical concentrations in the exhaust flow are substantially lower than from earlier predictions with simplified models. The performance of a baseline hydrogen/air RDE increased from 4940 s to 5000 s with the expansion flow chemistry, due to recombination of radicals and more production of H2O, resulting in additional heat release. Work sponsored by the Office of Naval Research.

Guaranteed Time Observations Support for Goddard High Resolution Spectrograph (GHRS) on HST

NASA Technical Reports Server (NTRS)

Beaver, Edward

1998-01-01

We assemble this final grant report by combining our previously submitted progress reports with the last year's progress report. Section 2 is the progress report for the June 1, 1991 to Nov. 14, 1995 period. Section 4 is the progress report for the Nov. 14, 1996 to Dec. 31, 1996 period. Section 5 is the progress report for the Nov. 14 to Aug. 31, 1997 period. Section 6 is the new progress report for the Sept. 15, 1997 to Nov. 14, 1998 final period. Section 3 is a summary of our spare detector high voltage transient tests activity in 1992 in support of the renewed safe operation of the GHRS HST D1 detector. Note that we have left the format of each progress report the same as originally sent out. The slight differences in format presentation are thus intended.

Enhancing undergraduate students' chemistry understanding through project-based learning in an IT environment

NASA Astrophysics Data System (ADS)

Barak, Miri; Dori, Yehudit Judy

2005-01-01

Project-based learning (PBL), which is increasingly supported by information technologies (IT), contributes to fostering student-directed scientific inquiry of problems in a real-world setting. This study investigated the integration of PBL in an IT environment into three undergraduate chemistry courses, each including both experimental and control students. Students in the experimental group volunteered to carry out an individual IT-based project, whereas the control students solved only traditional problems. The project included constructing computerized molecular models, seeking information on scientific phenomena, and inquiring about chemistry theories. The effect of the PBL was examined both quantitatively and qualitatively. The quantitative analysis was based on a pretest, a posttest, and a final examination, which served for comparing the learning gains of the two research groups. For the qualitative analysis, we looked into the experimental students' performance, as reflected by the projects they had submitted. In addition, think alou interviews and observations helped us gain insight into the students' conceptual understanding of molecular structures. Students who participated in the IT-enhanced PBL performed significantly better than their control classmates not only on their posttest but also on their course final examination. Analyzing the qualitative findings, we concluded that the construction of computerized models and Web-based inquiry activities helped promote students' ability of mentally traversing the four levels of chemistry understanding: symbolic, macroscopic, microscopic, and process. More generally, our results indicated that incorporating IT-rich PBL into freshmen courses can enhance students' understanding of chemical concepts, theories, and molecular structures.

Mars Aqueous Chemistry Experiment (MACE)

NASA Technical Reports Server (NTRS)

Benton, Clark C. (Editor)

1995-01-01

The concept of an aqueous-based chemical analyzer for Martian surface materials has been demonstrated to be feasible. During the processes of analysis, design, breadboarding, and most importantly, testing, it has become quite apparent that there are many challenges in implementing such a system. Nonetheless, excellent progress has been made and a number of problems which arose have been solved. The ability to conduct this work under a development environment which is separate and which precedes the project-level development has allowed us to find solutions to these implementation realities at low cost. If the instrument had been selected for a mission without this laboratory pre-project work, the costs of implementation would be much higher. In the four areas covered in Sections D, E, F, and G of this Final Report, outstanding progress has been made. There still remains the task of flight-qualifying certain of the components. This is traditionally done under the aegis of a Flight Project, but just as the concept development can be done at much lower cost when kept small and focused, so could the qualification program of critical parts benefit. We recommend, therefore, that NASA consider means of such qualifications and brass-boarding, in advance of final flight development. This is a generic recommendation, but hardware such as the Mars aqueous chemistry experiment (MACE) and other similarly-new concepts are particularly applicable. MACE now has wide versatility, in being able to reliably dispense both liquids and solids as chemical reagents to an entire suite of samples. The hardware and the experiment is much simpler than was developed for the Viking Biology instrument, yet can accomplish all the inorganic chemical measurements that the Viking desing was capable of. In addition, it is much more flexible and versatile to new experiment protocols (and reagents) than the Viking design ever could have been. MACE opens up the opportunity for many different scientific disciplines to design sub- experiments and to benefit from the investigations that can be conducted. In this sense, it will have the value of a facility, although our recommendation would be that it be under the stewardship of a single lead investigator to insure that conflicting requirements not compromise the straight-forward design that have been achieved. MACE is an excellent candidate for upcoming Mars missions, including the Mars Surveyor Program (MSP) lander missions in 2001 and 2003. In addition, it could be used for any mission to the surface of any other planet or planetary body (including small bodies). An important next step is to encourage various investigators to propose specific uses for this experiment that specifically address their major scientific objectives for upcoming missions.

Students From Highlands Ranch Triumph in Colorado Science Bowl

Science.gov Websites

final round of rapid-fire questions about physics, math, biology, astronomy, chemistry, computers and interest in science and math. The competition has evolved into one of the Energy Department's premier

Surface Chemistry of Nano-Structured Mixed Metal Oxide Films

DTIC Science & Technology

2012-12-11

surface chemical and catalytic properties of the films, and finally (iv) we also investigated some of these materials as electrodes for the photo-oxidation of water and as anode materials for lithium ion batteries .

Microgravity Science and Applications Flight Programs, January - March 1987, selected papers, volume 1

NASA Technical Reports Server (NTRS)

1988-01-01

A compilation of papers presented at this conference is given. The science dealing with materials and fluids and with fundamental studies in physics and chemistry in a low gravity environment is examined. Program assessments are made along with directions for progress in the future use of the space shuttle program.

Quantum Monte Carlo Methods for First Principles Simulation of Liquid Water

ERIC Educational Resources Information Center

Gergely, John Robert

2009-01-01

Obtaining an accurate microscopic description of water structure and dynamics is of great interest to molecular biology researchers and in the physics and quantum chemistry simulation communities. This dissertation describes efforts to apply quantum Monte Carlo methods to this problem with the goal of making progress toward a fully "ab initio"…

Changes in soil amino composition and microbial N acquisition strategies in response to woody plant invasion of grasslands

USDA-ARS?s Scientific Manuscript database

Changes in land cover have the potential to alter nutrient cycling through changes in carbon input chemistry, microbial community structure, and even soil structure. In the Rio Grande plains region of southern Texas, overgrazing and fire suppression have resulted in progressive encroachment of N-fix...

Analytical Chemistry Division. Annual progress report for period ending December 31, 1980

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lyon, W.S.

1981-05-01

This report is divided into: analytical methodology; mass and emission spectrometry; technical support; bio/organic analysis; nuclear and radiochemical analysis; quality assurance, safety, and tabulation of analyses; supplementary activities; and presentation of research results. Separate abstracts were prepared for the technical support, bio/organic analysis, and nuclear and radiochemical analysis. (DLC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boparai, A. S.; Bowers, D. L.; Graczyk, D. G.

This report summarizes the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year (FY) 1998 (October 1997 through September 1998). This annual progress report, which is the fifteenth in this series for the ACL, describes effort on continuing projects, work on new projects, and contributions of the ACL staff to various programs at ANL.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, D. W.; Boparai, A. S.; Bowers, D. L.

This report summarizes the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year (FY) 1999 (October 1998 through September 1999). This annual progress report, which is the sixteenth in this series for the ACL, describes effort on continuing projects, work on new projects, and contributions of the ACL staff to various programs at ANL.

Mars aqueous chemistry experiment

NASA Technical Reports Server (NTRS)

Clark, Benton C.; Mason, Larry W.

1994-01-01

Mars Aqueous Chemistry Experiment (MACE) is designed to conduct a variety of measurements on regolith samples, encompassing mineral phase analyses, chemical interactions with H2O, and physical properties determinations. From these data, much can be learned or inferred regarding the past weathering environment, the contemporaneous soil micro-environments, and the general chemical and physical state of the Martian regolith. By analyzing both soil and duricrust samples, the nature of the latter may become more apparent. Sites may be characterized for comparative purposes and criteria could be set for selection of high priority materials on future sample return missions. The second year of the MACE project has shown significant progress in two major areas. MACE Instrument concept definition is a baseline design that has been generated for the complete MACE instrument, including definition of analysis modes, mass estimates and thermal model. The design includes multiple reagent reservoirs, 10 discrete analysis cells, sample manipulation capability, and thermal control. The MACE Measurement subsystems development progress is reported regarding measurement capabilities for aqueous ion sensing, evolved gas sensing, solution conductivity measurement, reagent addition (titration) capabilities, and optical sensing of suspended particles.

Recent progress in [11 C]carbon dioxide ([11 C]CO2 ) and [11 C]carbon monoxide ([11 C]CO) chemistry.

PubMed

Taddei, Carlotta; Gee, Antony D

2018-03-01

[ 11 C]Carbon dioxide ([ 11 C]CO 2 ) and [ 11 C]carbon monoxide ([ 11 C]CO) are 2 attractive precursors for labelling the carbonyl position (C═O) in a vast range of functionalised molecules (eg, ureas, amides, and carboxylic acids). The development of radiosynthetic methods to produce functionalised 11 C-labelled compounds is required to enhance the radiotracers available for positron emission tomography, molecular, and medical imaging applications. Following a brief summary of secondary 11 C-precursor production and uses, the review focuses on recent progress with direct 11 C-carboxylation routes with [ 11 C]CO 2 and 11 C-carbonylation with [ 11 C]CO. Novel approaches to generate [ 11 C]CO using CO-releasing molecules (CO-RMs), such as silacarboxylic acids and disilanes, applied to radiochemistry are described and compared with standard [ 11 C]CO production methods. These innovative [ 11 C]CO synthesis strategies represent efficient and reliable [ 11 C]CO production processes, enabling the widespread use of [ 11 C]CO chemistry within the wider radiochemistry community. Copyright © 2017 John Wiley & Sons, Ltd.

Nanofluidics in two-dimensional layered materials: inspirations from nature.

PubMed

Gao, Jun; Feng, Yaping; Guo, Wei; Jiang, Lei

2017-08-29

With the advance of chemistry, materials science, and nanotechnology, significant progress has been achieved in the design and application of synthetic nanofluidic devices and materials, mimicking the gating, rectifying, and adaptive functions of biological ion channels. Fundamental physics and chemistry behind these novel transport phenomena on the nanoscale have been explored in depth on single-pore platforms. However, toward real-world applications, one major challenge is to extrapolate these single-pore devices into macroscopic materials. Recently, inspired partially by the layered microstructure of nacre, the material design and large-scale integration of artificial nanofluidic devices have stepped into a completely new stage, termed 2D nanofluidics. Unique advantages of the 2D layered materials have been found, such as facile and scalable fabrication, high flux, efficient chemical modification, tunable channel size, etc. These features enable wide applications in, for example, biomimetic ion transport manipulation, molecular sieving, water treatment, and nanofluidic energy conversion and storage. This review highlights the recent progress, current challenges, and future perspectives in this emerging research field of "2D nanofluidics", with emphasis on the thought of bio-inspiration.

Mars aqueous chemistry experiment

NASA Astrophysics Data System (ADS)

Clark, Benton C.; Mason, Larry W.

1994-06-01

Mars Aqueous Chemistry Experiment (MACE) is designed to conduct a variety of measurements on regolith samples, encompassing mineral phase analyses, chemical interactions with H2O, and physical properties determinations. From these data, much can be learned or inferred regarding the past weathering environment, the contemporaneous soil micro-environments, and the general chemical and physical state of the Martian regolith. By analyzing both soil and duricrust samples, the nature of the latter may become more apparent. Sites may be characterized for comparative purposes and criteria could be set for selection of high priority materials on future sample return missions. The second year of the MACE project has shown significant progress in two major areas. MACE Instrument concept definition is a baseline design that has been generated for the complete MACE instrument, including definition of analysis modes, mass estimates and thermal model. The design includes multiple reagent reservoirs, 10 discrete analysis cells, sample manipulation capability, and thermal control. The MACE Measurement subsystems development progress is reported regarding measurement capabilities for aqueous ion sensing, evolved gas sensing, solution conductivity measurement, reagent addition (titration) capabilities, and optical sensing of suspended particles.

ANNUAL REPORT, JULY 1, 1958

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1959-02-01

This annual report of Brookhaven National Laboratory describes its program and activities for the fiscal year 1958. The progress and trends of the research program are presented along with a description of the operational, service, and administrative activities of the Laboratory. The scientific and technical details of the many research and development activities are covered more fully in scientific and technical periodicals and in the quarterly scientific progress reports and other scientiflc reports of the Laboratory. A list of all publications for July 1, 1957 to June 30, 1958, is given. Status and progress are given in fields of physics,more » accelerator development, instrumentation, applied mathematics, chemistry, nuclear engineering, biology, and medical research. (For preceding period see BNL-462.) (W.D.M.)« less

Profiles in chemistry: a historical perspective on the national organic symposium.

PubMed

Fenlon, Edward E; Myers, Brian J

2013-06-21

This perspective delineates the history of the National Organic Chemistry Symposium (NOS) and, in doing so, traces the development of organic chemistry over the past 88 years. The NOS is the premier event sponsored by the ACS Division of Organic Chemistry (ORGN) and has been held in odd-numbered years since 1925, with the exceptions of 1943 and 1945. During the 42 symposia, 332 chemists have given 549 plenary lectures. The role the NOS played in the launch of The Journal of Organic Chemistry and Organic Reactions and the initiation of the Roger Adams Award are discussed. Representative examples highlighting the chemistry presented in each era are described, and the evolution of the field is examined by assigning each NOS talk to one of seven subdisciplines and analyzing how the number of talks in each subdiscipline has changed over time. Comparisons of the demographics of speakers, attendees, and ORGN members are made, and superlatives are noted. Personal interest stories of the speakers are discussed, along with the relationships among them, especially their academic lineage. Logistical aspects of the NOS and their historical trends are reviewed. Finally, the human side of science is examined, where over the past century, the NOS has been intertwined with some of the most heated debates in organic chemistry. Conflicts and controversies involving free radicals, reaction mechanisms, and nonclassical carbocations are discussed.

How Important are the Laws of Definite and Multiple Proportions in Chemistry and Teaching Chemistry? A History and Philosophy of Science Perspective

NASA Astrophysics Data System (ADS)

Niaz, Mansoor

The main objectives of this study are:(1) to elaborate a framework based on a rational reconstruction of developments that led to the formulation of the laws of definite and multiple proportions; (2) to ascertain students' views of the two laws; (3) to formulate criteria based on the framework for evaluating chemistry textbooks' treatment of the two laws; and (4) to provide a rationale for chemistry teachers to respond to the question: Can we teach chemistry without the laws of definite and multiple proportions? Results obtained show that most of the textbooks present the laws of definite and multiple proportions within an inductivist perspective, characterized by the following sequence: experimental findings showed that chemical elements combined in fixed/multiple proportions, followed by the formulation of the laws of definite and multiple proportions, and finally Dalton's atomic theory was postulated to explain the laws. Students were found to be reluctant to question the laws that they learnt as the building blocks of chemistry. It is concluded that by emphasizing the laws of definite and multiple proportions, textbooks inevitably endorse the dichotomy between theories and laws, which is questioned by philosophers of science (Lakatos 1970; Giere 1995a, b). An alternative approach is presented which shows that we can teach chemistry without the laws of definite and multiple proportions.

Students' Energy Understanding Across Biology, Chemistry, and Physics Contexts

NASA Astrophysics Data System (ADS)

Opitz, S. T.; Neumann, K.; Bernholt, S.; Harms, U.

2017-07-01

Energy is considered both as a disciplinary core idea and as a concept cutting across science disciplines. Most previous approaches studied progressing energy understanding in specific disciplinary contexts, while disregarding the relation of understanding across them. Hence, this study provides a systematic analysis of cross-disciplinary energy learning. On the basis of a cross-sectional study with n = 742 students from grades 6, 8, and 10, we analyze students' progression in understanding energy across biology, chemistry, and physics contexts. The study is guided by three hypothetical scenarios that describe how the connection between energy understanding in the three disciplinary contexts changes across grade levels. These scenarios are compared using confirmatory factor analysis (CFA). The results suggest that, from grade 6 to grade 10, energy understanding in the three disciplinary contexts is highly interrelated, thus indicating a parallel progression of energy understanding in the three disciplinary contexts. In our study, students from grade 6 onwards appeared to have few problems to apply one energy understanding across the three disciplinary contexts. These findings were unexpected, as previous research concluded that students likely face difficulties in connecting energy learning across disciplinary boundaries. Potential reasons for these results and the characteristics of the observed cross-disciplinary energy understanding are discussed in the light of earlier findings and implications for future research, and the teaching of energy as a core idea and a crosscutting concept are addressed.

Analytical Chemistry Division annual progress report for period ending December 31, 1988

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

The Analytical Chemistry Division of Oak Ridge National Laboratory (ORNL) is a large and diversified organization. As such, it serves a multitude of functions for a clientele that exists both in and outside of ORNL. These functions fall into the following general categories: (1) Analytical Research, Development, and Implementation. The division maintains a program to conceptualize, investigate, develop, assess, improve, and implement advanced technology for chemical and physicochemical measurements. Emphasis is on problems and needs identified with ORNL and Department of Energy (DOE) programs; however, attention is also given to advancing the analytical sciences themselves. (2) Programmatic Research, Development, andmore » Utilization. The division carries out a wide variety of chemical work that typically involves analytical research and/or development plus the utilization of analytical capabilities to expedite programmatic interests. (3) Technical Support. The division performs chemical and physicochemical analyses of virtually all types. The Analytical Chemistry Division is organized into four major sections, each of which may carry out any of the three types of work mentioned above. Chapters 1 through 4 of this report highlight progress within the four sections during the period January 1 to December 31, 1988. A brief discussion of the division's role in an especially important environmental program is given in Chapter 5. Information about quality assurance, safety, and training programs is presented in Chapter 6, along with a tabulation of analyses rendered. Publications, oral presentations, professional activities, educational programs, and seminars are cited in Chapters 7 and 8.« less

Whale baleen trace element signatures: a predictor of environmental life history?

NASA Astrophysics Data System (ADS)

Wilcox Freeburg, E.; Brault, S.; Mayo, C.; Oktay, S.; Hannigan, R.

2009-12-01

The analysis of trace element composition of biogenic structures (e.g., otoliths, feathers) by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) provides unique insights into the environmental life history of individuals. We studied the trace element chemistry of right whale baleens in an attempt to reconstruct migration patterns. Though much is known about the feeding and breeding habitats of these whales, little is known about the location in which they spend most of their adult years. Baleens, made of keratin, grow continuously and are metabolically inactive. Previous work showed that the stable isotope chemistry along the length of a baleen records changes in diet, such as weaning. Baleen chemistry should, therefore, also record the environmental life history of the individual. Trace metal chemistry along a single baleen plate from a right whale were analyzed by LA-ICP-MS. Semi-quantitative elemental signatures were obtained using NIST 612 (glass standard) and MACS-3 (calcium carbonate standard). These concentrations were then compared for accuracy to acid digested baleen laterally adjacent to the laser ablation site via aqueous ICP-MS. Elemental chemistry was compared to known feeding/breeding locations of the individual (water chemistry). Using these comparisons as well as principal components analysis, life history of the individual was reconstructed. Development of an in-house keratin standard is in progress and is expected to strengthen the confidence in results. Future work is expected to bring a more complete knowledge of right whale wintering habits.

Discovery and characterization of natural products that act as pheromones in fish.

PubMed

Li, Ke; Buchinger, Tyler J; Li, Weiming

2018-06-20

Covering: up to 2018 Fish use a diverse collection of molecules to communicate with conspecifics. Since Karlson and Lüscher termed these molecules 'pheromones', chemists and biologists have joined efforts to characterize their structures and functions. In particular, the understanding of insect pheromones developed at a rapid pace, set, in part, by the use of bioassay-guided fractionation and natural product chemistry. Research on vertebrate pheromones, however, has progressed more slowly. Initially, biologists characterized fish pheromones by screening commercially available compounds suspected to act as pheromones based upon their physiological function. Such biology-driven screening has proven a productive approach to studying pheromones in fish. However, the many functions of fish pheromones and diverse metabolites that fish release make predicting pheromone identity difficult and necessitate approaches led by chemistry. Indeed, the few cases in which pheromone identification was led by natural product chemistry indicated novel or otherwise unpredicted compounds act as pheromones. Here, we provide a brief review of the approaches to identifying pheromones, placing particular emphasis on the promise of using natural product chemistry together with assays of biological activity. Several case studies illustrate bioassay-guided fractionation as an approach to pheromone identification in fish and the unexpected diversity of pheromone structures discovered by natural product chemistry. With recent advances in natural product chemistry, bioassay-guided fractionation is likely to unveil an even broader collection of pheromone structures and enable research that spans across disciplines.

An Aerosol Physical Chemistry Model for the Upper Troposphere

NASA Technical Reports Server (NTRS)

Lin, Jin-Sheng

2001-01-01

This report is the final report for the Cooperative Agreement NCC2-1000. The tasks outlined in the various proposals are listed with a brief comment as to the research performed. The publications titles are: The effects of particle size and nitric acid uptake on the homogenous freezing of sulfate aerosols; Parameterization of an aerosol physical chemistry model (APCM) for the NH3/H2SO4/HNO3/H2O system at cold temperatures; and The onset, extent and duration of dehydration in the Southern Hemisphere polar vortex.

Chemistry Data for Geothermometry Mapping of Deep Hydrothermal Reservoirs in Southeastern Idaho

DOE Data Explorer

Earl Mattson

2016-01-18

This dataset includes chemistry of geothermal water samples of the Eastern Snake River Plain and surrounding area. The samples included in this dataset were collected during the springs and summers of 2014 and 2015. All chemical analysis of the samples were conducted in the Analytical Laboratory at the Center of Advanced Energy Studies in Idaho Falls, Idaho. This data set supersedes #425 submission and is the final submission for AOP 3.1.2.1 for INL. Isotopic data collected by Mark Conrad will be submitted in a separate file.

Corrosion performance of alternative steam generator materials and designs. Volume 2. Posttest examination of a seawater-faulted alternative materials model steam generator. Final report. [PWR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krupowicz, J.J.; Scott, D.B.; Fink, G.C.

Corrosion results obtained from the post-test non-destructive and destructive examinations of an alternative materials model steam generator are described in this final report. The model operated under representative thermal and hydraulic and accelerated (high seawater contaminant concentration) steam generator secondary water chemistry conditions. Total exposure consisted of 114 steaming days under all volatile treatment (AVT) chemistry conditions followed by 282 fault steaming days at a 30 ppM chloride concentration in the secondary bulk water. Various support plate and lattice strip support designs incorporated Types 347, 405, 409 and SCR-3 stainless steels; Alloys 600 and 690; and carbon steel. Heat transfermore » tube materials included Alloy 600 in various heat treated conditions, Alloy 690, and Alloy 800. All tubing materials in this test exhibited moderate pitting, primarily in the sludge pile region above the tubesheet.« less

Corrosion performance of alternative steam generator materials and designs. Volume 3. Posttest examination of a freshwater-faulted alternative materials model steam generator. Final report. [PWR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krupowicz, J.J.; Scott, D.B.; Rentler, R.M.

Corrosion results obtained from the post-test non-destructive and destructive examinations of an alternative materials model steam generator are described in this final report. The model operated under representative thermal and hydraulic and accelerated (high fresh water contaminant concentration) steam generator secondary water chemistry conditions. Total exposure consisted of 114 steaming days under all volatile treatment (AVT) chemistry conditions followed by 358 fault steaming days at a 40 ppM sulfate concentration in the secondary bulk water. Various support plate and lattice strip support designs incorporated Types 347, 405, 409 and SCR-3 stainless steels; Alloys 600 and 690; and carbon steel. Heatmore » transfer tube materials included Alloy 600 in various heat treated conditions, Alloy 690, and Alloy 800. All tubing materials in this test exhibited significant general corrosion beneath thick surface deposits.« less

Synthesis meets theory: Past, present and future of rational chemistry

NASA Astrophysics Data System (ADS)

Fianchini, Mauro

2017-11-01

Chemical synthesis has its roots in the empirical approach of alchemy. Nonetheless, the birth of the scientific method, the technical and technological advances (exploiting revolutionary discoveries in physics) and the improved management and sharing of growing databases greatly contributed to the evolution of chemistry from an esoteric ground into a mature scientific discipline during these last 400 years. Furthermore, thanks to the evolution of computational resources, platforms and media in the last 40 years, theoretical chemistry has added to the puzzle the final missing tile in the process of "rationalizing" chemistry. The use of mathematical models of chemical properties, behaviors and reactivities is nowadays ubiquitous in literature. Theoretical chemistry has been successful in the difficult task of complementing and explaining synthetic results and providing rigorous insights when these are otherwise unattainable by experiment. The first part of this review walks the reader through a concise historical overview on the evolution of the "model" in chemistry. Salient milestones have been highlighted and briefly discussed. The second part focuses more on the general description of recent state-of-the-art computational techniques currently used worldwide by chemists to produce synergistic models between theory and experiment. Each section is complemented by key-examples taken from the literature that illustrate the application of the technique discussed therein.

A Brief Review on Multivalent Intercalation Batteries with Aqueous Electrolytes.

PubMed

Guduru, Ramesh K; Icaza, Juan C

2016-02-26

Rapidly growing global demand for high energy density rechargeable batteries has driven the research toward developing new chemistries and battery systems beyond Li-ion batteries. Due to the advantages of delivering more than one electron and giving more charge capacity, the multivalent systems have gained considerable attention. At the same time, affordability, ease of fabrication and safety aspects have also directed researchers to focus on aqueous electrolyte based multivalent intercalation batteries. There have been a decent number of publications disclosing capabilities and challenges of several multivalent battery systems in aqueous electrolytes, and while considering an increasing interest in this area, here, we present a brief overview of their recent progress, including electrode chemistries, functionalities and challenges.

2D nanomaterials assembled from sequence-defined molecules

DOE PAGES

Mu, Peng; Zhou, Guangwen; Chen, Chun-Long

2017-10-21

Two dimensional (2D) nanomaterials have attracted broad interest owing to their unique physical and chemical properties with potential applications in electronics, chemistry, biology, medicine and pharmaceutics. Due to the current limitations of traditional 2D nanomaterials (e.g., graphene and graphene oxide) in tuning surface chemistry and compositions, 2D nanomaterials assembled from sequence-defined molecules (e.g., DNAs, proteins, peptides and peptoids) have recently been developed. They represent an emerging class of 2D nanomaterials with attractive physical and chemical properties. Here, we summarize the recent progress in the synthesis and applications of this type of sequence-defined 2D nanomaterials. We also discuss the challenges andmore » opportunities in this new field.« less

2D nanomaterials assembled from sequence-defined molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mu, Peng; Zhou, Guangwen; Chen, Chun-Long

Two dimensional (2D) nanomaterials have attracted broad interest owing to their unique physical and chemical properties with potential applications in electronics, chemistry, biology, medicine and pharmaceutics. Due to the current limitations of traditional 2D nanomaterials (e.g., graphene and graphene oxide) in tuning surface chemistry and compositions, 2D nanomaterials assembled from sequence-defined molecules (e.g., DNAs, proteins, peptides and peptoids) have recently been developed. They represent an emerging class of 2D nanomaterials with attractive physical and chemical properties. Here, we summarize the recent progress in the synthesis and applications of this type of sequence-defined 2D nanomaterials. We also discuss the challenges andmore » opportunities in this new field.« less

Ethics in Science: The Unique Consequences of Chemistry

PubMed Central

Kovac, Jeffrey

2015-01-01

This article discusses the ethical issues unique to the science and practice of chemistry. These issues arise from chemistry’s position in the middle between the theoretical and the practical, a science concerned with molecules that are of the right size to directly affect human life. Many of the issues are raised by the central activity of chemistry––synthesis. Chemists make thousands of new substances each year. Many are beneficial, but others are threats. Since the development of the chemical industry in the nineteenth century, chemistry has contributed to the deterioration of the environment but has also helped to reduce pollution. Finally, we discuss the role of codes of ethics and whether the current codes of conduct for chemists are adequate for the challenges of today’s world. PMID:26155729

The Chemistry of Extragalactic Carbon Stars

NASA Technical Reports Server (NTRS)

Woods, Paul; Walsh, C.; Cordiner, M. A.; Kemper, F.

2013-01-01

Prompted by the ongoing interest in Spitzer Infrared Spectrometer spectra of carbon stars in the Large Magellanic Cloud, we have investigated the circumstellar chemistry of carbon stars in low-metallicity environments. Consistent with observations, our models show that acetylene is particularly abundant in the inner regions of low metallicity carbon-rich asymptotic giant branch stars - more abundant than carbon monoxide. As a consequence, larger hydrocarbons have higher abundances at the metallicities of the Magellanic Clouds than in stars with solar metallicity. We also find that the oxygen and nitrogen chemistry is suppressed at lower metallicity, as expected. Finally, we calculate molecular line emission from carbon stars in the Large and Small Magellanic Cloud and find that several molecules should be readily detectable with the Atacama Large Millimeter Array at Full Science operations.

The Essential Role for Laboratory Studies in Atmospheric Chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burkholder, James B.; Abbatt, Jonathan P. D.; Barnes, Ian

Laboratory studies of atmospheric chemistry characterize the nature of atmospherically relevant processes down to the molecular level, providing fundamental information used to assess how human activities drive environmental phenomena such as climate change, urban air pollution, ecosystem health, indoor air quality, and stratospheric ozone depletion. Laboratory studies have a central role in addressing the incomplete fundamental knowledge of atmospheric chemistry. This paper highlights the evolving science needs for this community and emphasizes how our knowledge is far from complete, hindering our ability to predict the future state of our atmosphere and to respond to emerging global environmental change issues. Finally,more » laboratory studies provide rich opportunities to expand our understanding of the atmosphere via collaborative research with the modeling and field measurement communities, and with neighboring disciplines.« less

TRIGA Mark II nuclear reactor facility. Final report, 1 July 1980--30 June 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryan, B.C.

1997-05-01

This report is a final culmination of activities funded through the Department of Energy`s (DOE) University Reactor Sharing Program, Grant DE-FG02-80ER10273, during the period 1 July 1980 through 30 June 1995. Progress reports have been periodically issued to the DOE, namely the Reactor Facility Annual Reports C00-2082/2219-7 through C00-2082/10723-21, which are contained as an appendix to this report. Due to the extent of time covered by this grant, summary tables are presented. Table 1 lists the fiscal year financial obligations of the grant. As listed in the original grant proposals, the DOE grant financed 70% of project costs, namely themore » total amount spent of these projects minus materials costs and technical support. Thus the bulk of funds was spent directly on reactor operations. With the exception of a few years, spending was in excess of the grant amount. As shown in Tables 2 and 3, the Reactor Sharing grant funded a immense number of research projects in nuclear engineering, geology, animal science, chemistry, anthropology, veterinary medicine, and many other fields. A list of these users is provided. Out of the average 3000 visitors per year, some groups participated in classes involving the reactor such as Boy Scout Merit Badge classes, teacher`s workshops, and summer internships. A large number of these projects met the requirements for the Reactor Sharing grant, but were funded by the University instead.« less

Development and Nature of Preservice Chemistry Teachers' Pedagogical Content Knowledge for Nature of Science

NASA Astrophysics Data System (ADS)

Demirdöğen, Betül; Hanuscin, Deborah L.; Uzuntiryaki-Kondakci, Esen; Köseoğlu, Fitnat

2016-08-01

The purpose of this case study is to delve into the complexities of the early development of preservice chemistry teachers' science teaching orientations, knowledge of learners, knowledge of instructional strategies, and knowledge of assessment during a two-semester intervention designed to enhance their pedagogical content knowledge (PCK) for teaching nature of science (NOS). Thirty preservice chemistry teachers enrolled in a Research in Science Education course participated in the study. Qualitative data sources included responses to an open-ended instrument, interviews, observations, and artifacts such as lesson plans and reflection papers. Through the in-depth analysis of explicit PCK and constant comparative method of analysis, we identified the influence of the intervention on participants' PCK for NOS. Analysis of data revealed four major themes related to the nature of preservice chemistry teachers' NOS teaching practices and their PCK for NOS: (1) prerequisite knowledge and beliefs are necessary to teach NOS, (2) there is a developmental progression of PCK for NOS from knowledge to application level, (3) teachers need some comfort in their NOS understanding to teach NOS, and (4) the higher integration of PCK components leads to successful NOS teaching practices. Implications for science teacher education and research are discussed.

In situ click chemistry: from small molecule discovery to synthetic antibodies

PubMed Central

Agnew, Heather D.; Lai, Bert; Lee, Su Seong; Lim, Jaehong; Nag, Arundhati; Pitram, Suresh; Rohde, Rosemary; Heath, James R.

2013-01-01

Advances in the fields of proteomics, molecular imaging, and therapeutics are closely linked to the availability of affinity reagents that selectively recognize their biological targets. Here we present a review of Iterative Peptide In Situ Click Chemistry (IPISC), a novel screening technology for designing peptide multiligands with high affinity and specificity. This technology builds upon in situ click chemistry, a kinetic target-guided synthesis approach where the protein target catalyzes the conjugation of two small molecules, typically through the azide–alkyne Huisgen cycloaddition. Integrating this methodology with solid phase peptide libraries enables the assembly of linear and branched peptide multiligands we refer to as Protein Catalyzed Capture Agents (PCC Agents). The resulting structures can be thought of as analogous to the antigen recognition site of antibodies and serve as antibody replacements in biochemical and cell-based applications. In this review, we discuss the recent progress in ligand design through IPISC and related approaches, focusing on the improvements in affinity and specificity as multiligands are assembled by target-catalyzed peptide conjugation. We compare the IPISC process to small molecule in situ click chemistry with particular emphasis on the advantages and technical challenges of constructing antibody-like PCC Agents. PMID:22836343

Synthetic Approach to biomolecular science by cyborg supramolecular chemistry.

PubMed

Kurihara, Kensuke; Matsuo, Muneyuki; Yamaguchi, Takumi; Sato, Sota

2018-02-01

To imitate the essence of living systems via synthetic chemistry approaches has been attempted. With the progress in supramolecular chemistry, it has become possible to synthesize molecules of a size and complexity close to those of biomacromolecules. Recently, the combination of precisely designed supramolecules with biomolecules has generated structural platforms for designing and creating unique molecular systems. Bridging between synthetic chemistry and biomolecular science is also developing methodologies for the creation of artificial cellular systems. This paper provides an overview of the recently expanding interdisciplinary research to fuse artificial molecules with biomolecules, that can deepen our understanding of the dynamical ordering of biomolecules. Using bottom-up approaches based on the precise chemical design, synthesis and hybridization of artificial molecules with biological materials have been realizing the construction of sophisticated platforms having the fundamental functions of living systems. The effective hybrid, molecular cyborg, approaches enable not only the establishment of dynamic systems mimicking nature and thus well-defined models for biophysical understanding, but also the creation of those with highly advanced, integrated functions. This article is part of a Special Issue entitled "Biophysical Exploration of Dynamical Ordering of Biomolecular Systems" edited by Dr. Koichi Kato. Copyright © 2017 Elsevier B.V. All rights reserved.

Networked Instructional Chemistry: Using Technology To Teach Chemistry

NASA Astrophysics Data System (ADS)

Smith, Stanley; Stovall, Iris

1996-10-01

Networked multimedia microcomputers provide new ways to help students learn chemistry and to help instructors manage the learning environment. This technology is used to replace some traditional laboratory work, collect on-line experimental data, enhance lectures and quiz sections with multimedia presentations, provide prelaboratory training for beginning nonchemistry- major organic laboratory, provide electronic homework for organic chemistry students, give graduate students access to real NMR data for analysis, and provide access to molecular modeling tools. The integration of all of these activities into an active learning environment is made possible by a client-server network of hundreds of computers. This requires not only instructional software but also classroom and course management software, computers, networking, and room management. Combining computer-based work with traditional course material is made possible with software management tools that allow the instructor to monitor the progress of each student and make available an on-line gradebook so students can see their grades and class standing. This client-server based system extends the capabilities of the earlier mainframe-based PLATO system, which was used for instructional computing. This paper outlines the components of a technology center used to support over 5,000 students per semester.

Protein organic chemistry and applications for labeling and engineering in live-cell systems.

PubMed

Takaoka, Yousuke; Ojida, Akio; Hamachi, Itaru

2013-04-08

The modification of proteins with synthetic probes is a powerful means of elucidating and engineering the functions of proteins both in vitro and in live cells or in vivo. Herein we review recent progress in chemistry-based protein modification methods and their application in protein engineering, with particular emphasis on the following four strategies: 1) the bioconjugation reactions of amino acids on the surfaces of natural proteins, mainly applied in test-tube settings; 2) the bioorthogonal reactions of proteins with non-natural functional groups; 3) the coupling of recognition and reactive sites using an enzyme or short peptide tag-probe pair for labeling natural amino acids; and 4) ligand-directed labeling chemistries for the selective labeling of endogenous proteins in living systems. Overall, these techniques represent a useful set of tools for application in chemical biology, with the methods 2-4 in particular being applicable to crude (living) habitats. Although still in its infancy, the use of organic chemistry for the manipulation of endogenous proteins, with subsequent applications in living systems, represents a worthy challenge for many chemists. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanoinformatics: an emerging area of information technology at the intersection of bioinformatics, computational chemistry and nanobiotechnology.

PubMed

González-Nilo, Fernando; Pérez-Acle, Tomás; Guínez-Molinos, Sergio; Geraldo, Daniela A; Sandoval, Claudia; Yévenes, Alejandro; Santos, Leonardo S; Laurie, V Felipe; Mendoza, Hegaly; Cachau, Raúl E

2011-01-01

After the progress made during the genomics era, bioinformatics was tasked with supporting the flow of information generated by nanobiotechnology efforts. This challenge requires adapting classical bioinformatic and computational chemistry tools to store, standardize, analyze, and visualize nanobiotechnological information. Thus, old and new bioinformatic and computational chemistry tools have been merged into a new sub-discipline: nanoinformatics. This review takes a second look at the development of this new and exciting area as seen from the perspective of the evolution of nanobiotechnology applied to the life sciences. The knowledge obtained at the nano-scale level implies answers to new questions and the development of new concepts in different fields. The rapid convergence of technologies around nanobiotechnologies has spun off collaborative networks and web platforms created for sharing and discussing the knowledge generated in nanobiotechnology. The implementation of new database schemes suitable for storage, processing and integrating physical, chemical, and biological properties of nanoparticles will be a key element in achieving the promises in this convergent field. In this work, we will review some applications of nanobiotechnology to life sciences in generating new requirements for diverse scientific fields, such as bioinformatics and computational chemistry.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsubara, Yasuo; Grills, David C.; Koide, Yoshihiro

Room-temperature ionic liquids (ILs) are a class of nonaqueous solvents that have expanded the realm of modern chemistry, drawing increasing interest over the last few decades, not only in terms of their own unique physical chemistry but also in many applications including organic synthesis, electrochemistry, and biological systems, wherein charged solutes (i.e., electrolytes) often play vital roles. But, our fundamental understanding of the dissolution of an electrolyte in an IL is still rather limited. For example, the activity of a charged species has frequently been assumed to be unity without a clear experimental basis. In this study, we have discussedmore » a standard component-based scheme for the dissolution of an electrolyte in an IL, supported by our observation of ideal Nernstian responses for the reduction of silver and ferrocenium salts in a representative IL, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([emim +][NTf 2 -] or [emim +][TFSI -]). Using this scheme, which was also supported by temperature-dependent measurements with ILs having longer alkyl chains in the imidazolium ring, and the solubility of the IL in water, we established the concept of Gibbs transfer energies of “pseudo-single ions” from the IL to conventional neutral molecular solvents (water, acetonitrile, and methanol). This concept, which bridges component- and constituent-based energetics, utilizes an extrathermodynamic assumption, which itself was justified by experimental observations. Furthermore, these energies enable us to eliminate inner potential differences between the IL and molecular solvents (solvent-solvent interactions), that is, on a practical level, conditional liquid junction potential differences, so that we can discuss ion-solvent interactions independently. Specifically, we have examined the standard electrode potential of the ferrocenium/ferrocene redox couple, Fc +/Fc, and the absolute intrinsic standard chemical potential of a proton in [emim +][NTf 2 -], finding that the proton is more acidic in the IL than in water by 6.5 ± 0.6 units on the unified pH scale. Finally, our results strengthen the progress on the physical chemistry of ions in IL solvent systems on the basis of their activities, providing a rigorous thermodynamic framework.« less

Influence of Audience Response System Technology on Student Performance in Organic Chemistry Lecture Class

ERIC Educational Resources Information Center

Lyubartseva, Ganna

2013-01-01

The use of audience response system (commonly known as clickers) supports communication and interactivity in class by allowing the instructor to ask thought-provoking questions and encouraging students to articulate and reflect their thinking, reveal misconceptions, probe the knowledge and follow their progress in the course. Recent studies on the…

Teaching the Philosophical Interpretations of Quantum Mechanics and Quantum Chemistry through Controversies

ERIC Educational Resources Information Center

Garritz, Andoni

2013-01-01

This study has the key premise of teaching history and philosophy of physical sciences to illustrate how controversies and rivalries among scientists play a key role in the progress of science and why scientific development is not only founded on the accumulation of experimental data. The author is a defender of teachers who consider…

Hands-On Data Analysis: Using 3D Printing to Visualize Reaction Progress Surfaces

ERIC Educational Resources Information Center

Higman, Carolyn S.; Situ, Henry; Blacklin, Peter; Hein, Jason E.

2017-01-01

Advances in 3D printing technology over the past decade have led to its expansion into all subfields of science, including chemistry. This technology provides useful teaching tools that facilitate communication of difficult chemical concepts to students and researchers. Presented here is the use of 3D printing technology to create tangible models…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiong, Qingang; Robichaud, David J.

As research activities continue, our understanding of biomass pyrolysis has been significantly elevated and we sought to arrange this Virtual Special Issue (VSI) in ACS Sustainable Chemistry & Engineering to report recent progress on computational and experimental studies of biomass pyrolysis. Beyond highlighting the five national laboratories' advancements, prestigious researchers in the field of biomass pyrolysis have been invited to report their most recent activities.

THE ROLE OF THE PHYSICAL SCIENCES IN ELECTRICAL-ELECTRONIC TECHNOLOGY. PROGRESS REPORT.

ERIC Educational Resources Information Center

BARLOW, MELVIN L.; SCHILL, WILLIAM J.

TO DETERMINE THE RELATIVE IMPORTANCE OF CHEMISTRY AND PHYSICS FOR INSTRUCTION IN ELECTRICAL AND ELECTRONIC TECHNOLOGY, 51 TECHNICAL WORKERS, 51 JUNIOR COLLEGE INSTRUCTORS, AND 11 EXPERTS RATED 240 SCIENTIFIC PRINCIPLES AS TO THEIR VALUE IN A TECHNICIAN'S WORK. THE THREE GROUPS AGREED ON THE RANK ORDER OF 15 TOPICS--(1) CURRENT ELECTRICITY, (2)…

Progress in the chemistry of shortleaf and loblolly pine bark flavonoids

Treesearch

R.W. Hemingway

1976-01-01

The forest products industries of the southern United States harvest approximately 7 million dry tons of pine bark each year. This resource receives little utilization other than recovery of fuel values. approximately 2 million dry tons (30-40% of bark dry weight) of potentially valuable polyflavonoids are burned annually. Conifer bark flavonoids have potential...

Spent refractory reuse as a slag conditioning additive in the EAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bennett, James P.; Kwong, Kyei-Sing; Krabbe, Rick

2000-01-01

Refractories removed from service in EAF applications are typically landfilled. A joint USDOE and Steel Manufacturers Association program involving industrial cooperators is evaluating spent refractory recycling/reuse. A review of current recycling practices and a review of progress towards controlling EAF slag chemistry and properties with the additions of basic spent refractories will be discussed.

Assessment Update: Progress, Trends, and Practices in Higher Education. Volume 29, Issue 5, September-October 2017

ERIC Educational Resources Information Center

Hundley, Stephen P., Ed.

2017-01-01

This issue of "Assessment Update" presents the following articles: (1) Using National Benchmarking Data to Improve Student Learning in Chemistry at Lebanon Valley College (Marc A. Harris); (2) Mutually Dependent Outcomes: Using Assessment to Improve First-Year Retention and Student Learning (Alan Bearman and Elaine Lewis); (3) Emergent…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, D.W.; Boparai, A.S.; Bowers, D.L.

The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year (FY) 1997 (October 1996 through September 1997). This annual progress report is the fourteenth in this series for the ACL, and it describes continuing effort on projects, work on new projects, and contributions of the ACL staff to various programs at ANL.

Synthetic Fabrication of Nanoscale MoS2-Based Transition Metal Sulfides

PubMed Central

Wang, Shutao; An, Changhua; Yuan, Jikang

2010-01-01

Transition metal sulfides are scientifically and technologically important materials. This review summarizes recent progress on the synthetic fabrication of transition metal sulfides nanocrystals with controlled shape, size, and surface functionality. Special attention is paid to the case of MoS2 nanoparticles, where organic (surfactant, polymer), inorganic (support, promoter, doping) compounds and intercalation chemistry are applied.

Strengthening STEM performance and persistence: Influence of undergraduate teaching assistants on entry-level STEM students

NASA Astrophysics Data System (ADS)

Philipp, Stephanie B.

Increasing retention of students in science, technology, engineering, or mathematics (STEM) programs of study is a priority for many colleges and universities. This study examines an undergraduate teaching assistant (UTA) program implemented in a general chemistry course for STEM majors to provide peer learning assistance to entrylevel students. This study measured the content knowledge growth of UTAs compared to traditional graduate teaching assistants (GTAs) over the semester, and described the development of peer learning assistance skills of the UTAs as an outcome of semesterlong training and support from both science education and STEM faculty. Impact of the UTA program on final exam grades, persistence of students to enroll in the next chemistry course required by their intended major, and STEM identity of students were estimated. The study sample comprised 284 students in 14 general chemistry recitation sections led by six UTAs and 310 students in 15 general chemistry recitation sections led by three traditional GTAs for comparison. Results suggested that both UTAs and GTAs made significant learning gains in general chemistry content knowledge, and there was no significant difference in content knowledge between UTA and GTA groups. Student evaluations, researcher observations, and chemistry faculty comments confirm UTAs were using the learning strategies discussed in the semester-long training program. UTA-led students rated their TAs significantly higher in teaching quality and student care and encouragement, which correlated with stronger STEM recognition by those students. The results of hierarchical linear model (HLM) analysis showed little variance in final exam grades explained by section-level variables; most variance was explained by student-level variables: mathematics ACT score, college GPA, and intention to enroll in the next general chemistry course. Students having higher college GPAs were helped more by having a UTA. Results from logistic regression of persistence outcome variable showed that students are three times more likely to persist to CHEM 202 if they had a UTA in CHEM 201. Other positive predictors of retention included having strong college grades, and having strong ACT math scores. Coupled with HLM analysis result that UTAs were more effective at helping students with higher college GPAs achieve higher grades, the stronger persistence of UTA-led students showed that the UTA program is an effective program for retention of introductory-level students in STEM majors.

The Effects of Clickers and Online Homework on Students' Achievement in General Chemistry

NASA Astrophysics Data System (ADS)

Gebru, Misganaw T.

Retention of an introductory general chemistry course material is vital for student success in future chemistry and chemistry-related courses. This study investigated the effects of clickers versus online homework on students' long-term content retention, examined the effectiveness of online homework versus no graded homework on students' achievement in a first-semester general chemistry course, and assessed students' attitudes toward the use of online homework. Students' data from the yearlong American Chemical Society General Chemistry (ACS GC97) exam, teacher-prepared final exams, and online surveys were analyzed to measure the effects of clickers and online homework on students' long-term content retention and performance, and to capture students' attitudes. A variety of methods including Welch ANOVA, independent samples t -test (Welch), Pearson's correlation, test of proportions, and Pearson's Chi-square test were used to analyze the data. The analyses indicated that the use of clickers or online homework did not significantly improve students' long-term content retention of general chemistry course material, that the use of online homework was more beneficial than, or at least as effective as no graded homework in improving students' performance, and students valued the fact that online homework provided immediate feedback. Additionally, results of this study revealed that greater numbers of students were retained in clicker and online homework classes than non-clicker, non-online homework classes and that various types of online homework systems used in general chemistry could impact student performance differently. Implications of the findings and future research directions were presented.

Relationships between acid deposition, watershed characteristics, and stream chemistry in Maryland's coastal plain. Final report. Volume 1. Text. Report for May 1984-June 1985

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, S.; Bartoshesky, J.; Heimbuch, D.

1987-06-01

Precipitation and stream-water chemistry data were collected from three watersheds in the Coastal Plain region of Maryland during the period May 1984 through June 1985 in an attempt to determine the potential effects of acidic deposition on the chemistry of these streams. The study streams included Lyons Creek, Morgan Creek, and Granny Finley Branch; these streams were chosen based on their differential responses to storm events observed in a survey of Coastal Plain streams in the spring of 1983. Lyons Creek typically exhibited lower pH, acid-neutralizing capacity, and concentrations of base cations than observed in the other streams. Sulfate massmore » balances suggest that the soils in the Lyons Creek watershed also have less affinity for sulfur retention than do soils of the other watersheds. Acidic pulses were observed in all three streams during the spring months; however, the magnitude of these pulses was less than that observed in 1983. Modeling of the relationships between precipitation chemistry, watershed interactions, and stream chemistry suggests that precipitation acidity can influence stream-water acidity, depending upon hydrological conditions and availabiility of acid-neutralizing materials in the watersheds.« less

Developing Professional Skills in a Third-Year Undergraduate Chemistry Course Offered in Western Australia

NASA Astrophysics Data System (ADS)

Dunn, Jeffrey G.; Kagi, Robert I.; Phillips, David N.

1998-10-01

"This unit gave me a broad industrial view of the chemical world and I am grateful for the professional skills I gained." That is the response of one graduate several years after he had taken the "Chemistry and Technology" unit that we present in the third year of the undergraduate chemistry course at Western Australia's Curtin University of Technology. Students in tertiary education are effectively "cocooned from the real world". There is a growing need for a teaching that links students to situations they will encounter upon gaining employment. The Chemistry and Technology unit has been developed over a 12-year period and is presented in the final semester of the course. It comprises six modules and is taught by lecturers from industry and the staff of the School. The Professional Practice, Consumer Chemistry, and Environmental modules are ones that most teachers could consider in their course. The other three modules are specific to Western Australia's needs, but could be modified or replaced to cater to other employment circumstances. A survey of recent graduates yielded complimentary responses to the appropriateness of such a unit in the course.

The role of student’s critical asking question in developing student’s critical thinking skills

NASA Astrophysics Data System (ADS)

Santoso, T.; Yuanita, L.; Erman, E.

2018-01-01

Questioning means thinking, and thinking is manifested in the form of questions. Research that studies the relationship between questioning and students’ critical thinking skills is little, if any. The aim of this study is to examine how student’s questions skill correlates to student’s critical thinking skills in learning of chemistry. The research design used was one group pretest-posttest design. The participants involved were 94 students, all of whom attended their last semesters, Chemistry Education of Tadulako University. A pre-test was administered to check participants’ ability to ask critical questions and critical thinking skills in learning chemistry. Then, the students were taught by using questioning technique. After accomplishing the lesson, a post-test was given to evaluate their progress. Obtained data were analyzed by using Pair-Samples T.Test and correlation methods. The result shows that the level of the questions plays an important role in critical thinking skills is the question levels of predictive, analysis, evaluation and inference.

The offer of chemistry to targeted therapy in cancer.

PubMed

Jemel, Ikram; Jellali, Karim; Elloumi, Jihene; Aifa, Sami

2011-12-01

Cancer therapy is facing the big challenge of destroying selectively tumour cells without harming the normal tissues. Chemotherapy was trying from the beginning to kill malignant cells because of their proliferative activity since normal cells are in general quiescent. Meanwhile side effects were produced due to the destruction of some normal cells that need regular proliferation. The discovery of biomarkers led to the identification of molecular targets within tumour cells in order to kill them selectively. Chemistry followed the progress of biomarkers biotechnology by the production of target specific antagonists which were the subject of many patents. Meanwhile novel problems of tumour resistance appeared and made the battle against cancer a non stop development of new strategies and new weapons. As a consequence, paralleled activities of patenting biomarkers and chemical antagonists are continuously generated. The offer of chemistry does not actually limit the efficiency of Targeted therapy but the identification of biomarkers is still missing the exclusive specificity to tumour cells.

The role of analytical chemistry in Niger Delta petroleum exploration: a review.

PubMed

Akinlua, Akinsehinwa

2012-06-12

Petroleum and organic matter from which the petroleum is derived are composed of organic compounds with some trace elements. These compounds give an insight into the origin, thermal maturity and paleoenvironmental history of petroleum, which are essential elements in petroleum exploration. The main tool to acquire the geochemical data is analytical techniques. Due to progress in the development of new analytical techniques, many hitherto petroleum exploration problems have been resolved. Analytical chemistry has played a significant role in the development of petroleum resources of Niger Delta. Various analytical techniques that have aided the success of petroleum exploration in the Niger Delta are discussed. The analytical techniques that have helped to understand the petroleum system of the basin are also described. Recent and emerging analytical methodologies including green analytical methods as applicable to petroleum exploration particularly Niger Delta petroleum province are discussed in this paper. Analytical chemistry is an invaluable tool in finding the Niger Delta oils. Copyright © 2011 Elsevier B.V. All rights reserved.

Covalent-Bond Formation via On-Surface Chemistry.

PubMed

Held, Philipp Alexander; Fuchs, Harald; Studer, Armido

2017-05-02

In this Review article pioneering work and recent achievements in the emerging research area of on-surface chemistry is discussed. On-surface chemistry, sometimes also called two-dimensional chemistry, shows great potential for bottom-up preparation of defined nanostructures. In contrast to traditional organic synthesis, where reactions are generally conducted in well-defined reaction flasks in solution, on-surface chemistry is performed in the cavity of a scanning probe microscope on a metal crystal under ultrahigh vacuum conditions. The metal first acts as a platform for self-assembly of the organic building blocks and in many cases it also acts as a catalyst for the given chemical transformation. Products and hence success of the reaction are directly analyzed by scanning probe microscopy. This Review provides a general overview of this chemistry highlighting advantages and disadvantages as compared to traditional reaction setups. The second part of the Review then focuses on reactions that have been successfully conducted as on-surface processes. On-surface Ullmann and Glaser couplings are addressed. In addition, cyclodehydrogenation reactions and cycloadditions are discussed and reactions involving the carbonyl functionality are highlighted. Finally, the first examples of sequential on-surface chemistry are considered in which two different functionalities are chemoselectively addressed. The Review gives an overview for experts working in the area but also offers a starting point to non-experts to enter into this exciting new interdisciplinary research field. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

76 FR 6762 - Drill Pipe From the People's Republic of China: Amended Final Determination of Critical...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-08

... the specific chemistry of the steel (i.e., carbon, stainless steel, or other alloy steel), and without... collar green tubes) and unfinished drill pipe (including drill pipe green tubes, which are tubes meeting...

Light Barrier for Non-Foil Packaging

DTIC Science & Technology

2010-12-16

packaging to reduce light-induced changes continues (Tung et al 2001). Lipid oxidation chemistry PRINTPACK Inc. Atlanta, Ga Item No. 0010 Final...complete protection against UV and visible light (i.e. opacity) is advisable. Photosensitizers particularly (e.g. flavonoids , riboflavin —especially for

Predictors of student success in entry-level science courses

NASA Astrophysics Data System (ADS)

Singh, Mamta K.

Although the educational evaluation process is useful and valuable and is supported by the Higher Education Act, a strong research base for program evaluation of college entry-level science courses is still lacking. Studies in science disciplines such as, biology, chemistry, and physics have addressed various affective and demographic factors and their relationships to student achievement. However, the literature contains little information that specifically addresses student biology content knowledge skills (basics and higher order thinking skills) and identifies factors that affect students' success in entry-level college science courses. These gate-keeping courses require detailed evaluation if the goal of an institution is to increase students' performance and success in these courses. These factors are, in fact, a stepping stone for increasing the number of graduates in Science, Technology, Engineering, and Mathematics (STEM) majors. The present study measured students' biology content knowledge and investigated students' performance and success in college biology, chemistry, and physics entry-level courses. Seven variables---gender, ethnicity, high school Grade Point Average (GPA), high school science, college major, school financial aid support, and work hours were used as independent variables and course final performance as a dichotomous dependent variable. The sample comprised voluntary student participants in entry-level science courses. The study attempted to explore eight research questions. Content knowledge assessments, demographic information analysis, multiple regression analysis, and binary logistic regression analysis were used to address research questions. The results suggested that high school GPA was a consistently good predictor of students' performance and success in entry-level science courses. Additionally, high school chemistry was a significant predictor variable for student success in entry-level biology and chemistry courses. Similarly, students' performance and success in entry-level physics courses were influenced by high school physics. Finally, the study developed student success equation with high school GAP and high school chemistry as good predictors of students' success in entry-level science courses.

Numerical simulation of turbulent combustion: Scientific challenges

NASA Astrophysics Data System (ADS)

Ren, ZhuYin; Lu, Zhen; Hou, LingYun; Lu, LiuYan

2014-08-01

Predictive simulation of engine combustion is key to understanding the underlying complicated physicochemical processes, improving engine performance, and reducing pollutant emissions. Critical issues as turbulence modeling, turbulence-chemistry interaction, and accommodation of detailed chemical kinetics in complex flows remain challenging and essential for high-fidelity combustion simulation. This paper reviews the current status of the state-of-the-art large eddy simulation (LES)/prob-ability density function (PDF)/detailed chemistry approach that can address the three challenging modelling issues. PDF as a subgrid model for LES is formulated and the hybrid mesh-particle method for LES/PDF simulations is described. Then the development need in micro-mixing models for the PDF simulations of turbulent premixed combustion is identified. Finally the different acceleration methods for detailed chemistry are reviewed and a combined strategy is proposed for further development.

Royal Society, Discussion on New Coal Chemistry, London, England, May 21, 22, 1980, Proceedings

NASA Astrophysics Data System (ADS)

1981-03-01

A discussion of new coal chemistry is presented. The chemical and physical structure of coal is examined in the first section, including structural studies of coal extracts, metal and metal complexes in coal and coal microporosity. The second section presents new advances in applied coal technology. The development of liquid fuels and chemicals from coal is given especial emphasis, with papers on the Sasol Synthol process, the Shell-Koppers gasification process, liquefaction and gasification in Germany, the Solvent Refined Coal process, the Exxon Donor Solvent liquefaction process and the Mobil Methanol-to-Gasoline process. Finally, some developments that will be part of the future of coal chemistry in the year 2000 are examined in the third section, including coal-based chemical complexes and the use of coal as an alternative source to oil for chemical feedstocks.

Corrosion chemistry closing comments: opportunities in corrosion science facilitated by operando experimental characterization combined with multi-scale computational modelling.

PubMed

Scully, John R

2015-01-01

Recent advances in characterization tools, computational capabilities, and theories have created opportunities for advancement in understanding of solid-fluid interfaces at the nanoscale in corroding metallic systems. The Faraday Discussion on Corrosion Chemistry in 2015 highlighted some of the current needs, gaps and opportunities in corrosion science. Themes were organized into several hierarchical categories that provide an organizational framework for corrosion. Opportunities to develop fundamental physical and chemical data which will enable further progress in thermodynamic and kinetic modelling of corrosion were discussed. These will enable new and better understanding of unit processes that govern corrosion at the nanoscale. Additional topics discussed included scales, films and oxides, fluid-surface and molecular-surface interactions, selected topics in corrosion science and engineering as well as corrosion control. Corrosion science and engineering topics included complex alloy dissolution, local corrosion, and modelling of specific corrosion processes that are made up of collections of temporally and spatially varying unit processes such as oxidation, ion transport, and competitive adsorption. Corrosion control and mitigation topics covered some new insights on coatings and inhibitors. Further advances in operando or in situ experimental characterization strategies at the nanoscale combined with computational modelling will enhance progress in the field, especially if coupling across length and time scales can be achieved incorporating the various phenomena encountered in corrosion. Readers are encouraged to not only to use this ad hoc organizational scheme to guide their immersion into the current opportunities in corrosion chemistry, but also to find value in the information presented in their own ways.

Modelling of Molecular Structures and Properties. Proceedings of the International Meeting of Physical Chemistry on Modeling of Molecular Structures and Properties in Physical Chemistry and Biophysics Organized by the Division de Chimie Physique of the Societe Francaise de Chimie Held in Nancy, France on 11-15 September 1989

DTIC Science & Technology

1990-01-01

expert systems, "intelligent" computer-aided instruction , symbolic learning . These aspects will be discussed, focusing on the specific problems the...VLSI chips) according to preliminary specifications. Finally ES are also used in computer-aided instruction (CAI) due to their ability of... instructions to process controllers), academic teaching (for mathematics , physics, foreign language, etc.). Domains of application The different

On the formulation and assessment of flamelet-generated manifolds applied to two-phase turbulent combustion

NASA Astrophysics Data System (ADS)

Bojko, Brian T.

Accounting for the effects of finite rate chemistry in reacting flows is intractable when considering the number of species and reactions to be solved for during a large scale flow simulation. This is especially complicated when solid/liquid fuels are also considered. While modeling the reacting boundary layer with the use of finite-rate chemistry may allow for a highly accurate description of the coupling between the flame and fuel surface, it is not tractable in large scale simulations when considering detailed chemical kinetics. It is the goal of this research to investigate a Flamelet-Generated Manifold (FGM) method in order to reduce the finite rate chemistry to a lookup table cataloged by progress variables and queried during runtime. In this study, simplified unsteady 1D flames with mass blowing are considered for a solid biomass fuel where the FGM method is employed as a model reduction strategy for potential application to multidimensional calculations. Two types of FGM are considered. The first are a set of steady-state flames differentiated by their scalar dissipation rate. Results show the use of steady flames produce unacceptable errors compared to the finite-rate chemistry solution, with temperature errors in excess of 45%. To avoid these errors, a new methodology for developing an unsteady FGM (UFGM) is presented that accounts for unsteady diffusion effects and greatly reduces errors in temperature with differences that are under 10%. The FGM modeling is then extended to individual droplet combustion with the development of a Droplet Flamelet-Generated Manifold (DFGM) to account for the effects of finite-rate chemistry of individual droplets. A spherically symmetric droplet model is developed for methanol and aluminum. The inclusion of finite-rate chemistry allows the capturing of the transition from diffusion to kinetically controlled combustion as the droplet diameter decreases. The droplet model is then used to create a DFGM by successively solving the 1D flame equations at varying drop sizes, where the source terms for energy, mixture fraction, and progress variable are cataloged as a function of normalized diameter. A unique coupling of the DFGM and planar UFGM is developed and is used to account for individual and gas phase combustion processes in turbulent combustion situations, such as spray flames, particle laden blasts, etc. The DFGM for the methanol and aluminum droplets are used in mixed Eulerian and Eulerian-Lagrangian formulations of compressible multiphase flows. System level simulations are conducted and compared experimental data for a methanol spray flame and an aluminized blast studied at the Explosives Components Facility (ECF) at Sandia National Laboratories.

Selecting automation for the clinical chemistry laboratory.

PubMed

Melanson, Stacy E F; Lindeman, Neal I; Jarolim, Petr

2007-07-01

Laboratory automation proposes to improve the quality and efficiency of laboratory operations, and may provide a solution to the quality demands and staff shortages faced by today's clinical laboratories. Several vendors offer automation systems in the United States, with both subtle and obvious differences. Arriving at a decision to automate, and the ensuing evaluation of available products, can be time-consuming and challenging. Although considerable discussion concerning the decision to automate has been published, relatively little attention has been paid to the process of evaluating and selecting automation systems. To outline a process for evaluating and selecting automation systems as a reference for laboratories contemplating laboratory automation. Our Clinical Chemistry Laboratory staff recently evaluated all major laboratory automation systems in the United States, with their respective chemistry and immunochemistry analyzers. Our experience is described and organized according to the selection process, the important considerations in clinical chemistry automation, decisions and implementation, and we give conclusions pertaining to this experience. Including the formation of a committee, workflow analysis, submitting a request for proposal, site visits, and making a final decision, the process of selecting chemistry automation took approximately 14 months. We outline important considerations in automation design, preanalytical processing, analyzer selection, postanalytical storage, and data management. Selecting clinical chemistry laboratory automation is a complex, time-consuming process. Laboratories considering laboratory automation may benefit from the concise overview and narrative and tabular suggestions provided.

The need and potential for building a integrated knowledge-base of the Earth-Human system

NASA Astrophysics Data System (ADS)

Jacobs, Clifford

2011-03-01

The pursuit of scientific understanding is increasingly based on interdisciplinary research. To understand more deeply the planet and its interactions requires a progressively more holistic approach, exploring knowledge coming from all scientific and engineering disciplines including but not limited to, biology, chemistry, computer sciences, geosciences, material sciences, mathematics, physics, cyberinfrastucture, and social sciences. Nowhere is such an approach more critical than in the study of global climate change in which one of the major challenges is the development of next-generation Earth System Models that include coupled and interactive representations of ecosystems, agricultural working lands and forests, urban environments, biogeochemistry, atmospheric chemistry, ocean and atmospheric currents, the water cycle, land ice, and human activities.

2D nanomaterials assembled from sequence-defined molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mu, Peng; Zhou, Guangwen; Chen, Chun-Long

Two dimensional (2D) nanomaterials have attracted broad interest owing to their unique physical and chemical properties with potential applications in electronics, chemistry, biology, medicine and pharmaceutics. Due to the current limitations of traditional 2D nanomaterials (e.g., graphene and graphene oxide) in tuning surface chemistry and compositions, 2D nanomaterials assembled from sequence-defined molecules (e.g., DNAs, proteins, peptides and peptoids) have recently been developed. They represent an emerging class of 2D nanomaterials with attractive physical and chemical properties. In this mini-review, we summarize the recent progress in the synthesis and applications of this type of sequence-defined 2D nanomaterials. The challenges and opportunitiesmore » in this new field are also discussed.« less

A Brief Review on Multivalent Intercalation Batteries with Aqueous Electrolytes

PubMed Central

Guduru, Ramesh K.; Icaza, Juan C.

2016-01-01

Rapidly growing global demand for high energy density rechargeable batteries has driven the research toward developing new chemistries and battery systems beyond Li-ion batteries. Due to the advantages of delivering more than one electron and giving more charge capacity, the multivalent systems have gained considerable attention. At the same time, affordability, ease of fabrication and safety aspects have also directed researchers to focus on aqueous electrolyte based multivalent intercalation batteries. There have been a decent number of publications disclosing capabilities and challenges of several multivalent battery systems in aqueous electrolytes, and while considering an increasing interest in this area, here, we present a brief overview of their recent progress, including electrode chemistries, functionalities and challenges. PMID:28344298

Publication and Retrieval of Computational Chemical-Physical Data Via the Semantic Web. Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ostlund, Neil

This research showed the feasibility of applying the concepts of the Semantic Web to Computation Chemistry. We have created the first web portal (www.chemsem.com) that allows data created in the calculations of quantum chemistry, and other such chemistry calculations to be placed on the web in a way that makes the data accessible to scientists in a semantic form never before possible. The semantic web nature of the portal allows data to be searched, found, and used as an advance over the usual approach of a relational database. The semantic data on our portal has the nature of a Giantmore » Global Graph (GGG) that can be easily merged with related data and searched globally via a SPARQL Protocol and RDF Query Language (SPARQL) that makes global searches for data easier than with traditional methods. Our Semantic Web Portal requires that the data be understood by a computer and hence defined by an ontology (vocabulary). This ontology is used by the computer in understanding the data. We have created such an ontology for computational chemistry (purl.org/gc) that encapsulates a broad knowledge of the field of computational chemistry. We refer to this ontology as the Gainesville Core. While it is perhaps the first ontology for computational chemistry and is used by our portal, it is only a start of what must be a long multi-partner effort to define computational chemistry. In conjunction with the above efforts we have defined a new potential file standard (Common Standard for eXchange – CSX for computational chemistry data). This CSX file is the precursor of data in the Resource Description Framework (RDF) form that the semantic web requires. Our portal translates CSX files (as well as other computational chemistry data files) into RDF files that are part of the graph database that the semantic web employs. We propose a CSX file as a convenient way to encapsulate computational chemistry data.« less

An examination of past and present influences on university chemistry education

NASA Astrophysics Data System (ADS)

Soliman, William Atef

This study examined the historical influences that have contributed to past and present-day university level chemistry education. The study was organized into three sections: First, by analyzing the academic genealogy, education origins of prominent chemists, Nobel Prize winners in chemistry and scientific patents awarded by countries; the major historical contributors to chemical education during the 19th century were identified; Secondly, by analyzing the educational backgrounds of current chemistry professors (n=12,120) in 407 universities in 40 countries around the world and six chemical education indicators for 25 countries; and finally the relationship, if any, between a country's chemical, biotechnology, defense, and petroleum industries to its level of chemistry education was investigated utilizing a multiple regression analysis between the monetary value of the industries and the extent of chemical education within each country. The findings indicated that the U.S., Britain, Germany, and France were major influencers of 19th century chemical education while the major present-day influencers of university chemical education are the U.S., Germany, Britain, France, Italy, and Japan. Pearson correlation coefficients indicated that the value of the chemical industry for a country was significantly related to (a) the number of chemistry doctorates awarded (p=.05), (b) chemistry Nobel awards (p=.001), (c) the number of chemistry publications (p=.001), and (d) prominence of the country in the chemical literature (p=.05). Multiple regression analysis indicated that the value of the biotechnology industry was significantly related to the number of Nobel awards (p=.007) and the number of chemistry publications (p=.001). The value of the defense industry was significantly related to chemistry doctorates (p=.002), chemistry Nobel awards (p=.001), the number of chemistry publications (p=.001), and prominence in the literature (p=.001). The value of the petroleum industry was not significantly related to any education variables. The findings suggest that university chemical education is influenced by a select group of countries and that chemical, biotechnology, and defense industry values are significantly related to the level of a country's chemical education. These findings may be valuable to those interested in the industrial and societal applications of chemical education.

Factors associated with the success of first-time African American freshmen taking introductory science lecture courses at a private HBCU

NASA Astrophysics Data System (ADS)

Smith, Kendra Leigh

This study had four purposes: (1) to investigate the relationship between performance in introductory biology or introductory chemistry lecture courses and their accompanying laboratory courses, (2) to investigate the relationship between performance in introductory biology or introductory chemistry lecture courses and a student's gender, (3) to investigate the relationship between performance in introductory biology or introductory chemistry lecture courses and a student's major, and (4) to investigate the relationship between performance in introductory biology or introductory chemistry lecture courses and a student's ACT scores. The sample consisted of 195 first--time freshmen who enrolled in and completed an introductory biology or an introductory chemistry lecture and laboratory courses during the fall semesters of 2007-2012. Of the 195 students, 61 were enrolled in introductory chemistry and 134 were enrolled in introductory biology courses. Logistic regression, via the Statistical Package for the Social Sciences (SPSS), was utilized to analyze several variables as they related to success in the lecture courses. Data were extracted from the university's student information system (BANNER), and analyses were conducted on biology and chemistry separately. The dependent variable for this study was a dichotomous variable for success and nonsuccess in introductory biology or introductory chemistry lecture course. The independent variables analyzed were student's gender, major, final grade in an accompanying biology or chemistry laboratory course, and ACT test scores (composite, mathematics, and science). Results indicate that concurrent enrollment in a biology laboratory course increased the likelihood of success by 15.64 times in the lecture course. Gender was found to not be a significant predictor of success for either introductory biology or introductory chemistry lecture courses. STEM majors were 9.6 times more likely to be successful than non-STEM majors in introductory chemistry lecture course. It was also found that the higher the given ACT score (composite, science, mathematics), the higher the rate of success (between a 1.19-1.44 odds increase for every one point increase in ACT score) in both introductory biology and introductory chemistry lecture courses.

In vivo metabolic labeling of sialoglycans in the mouse brain by using a liposome-assisted bioorthogonal reporter strategy

PubMed Central

Xie, Ran; Dong, Lu; Du, Yifei; Zhu, Yuntao; Hua, Rui; Zhang, Chen; Chen, Xing

2016-01-01

Mammalian brains are highly enriched with sialoglycans, which have been implicated in brain development and disease progression. However, in vivo labeling and visualization of sialoglycans in the mouse brain remain a challenge because of the blood−brain barrier. Here we introduce a liposome-assisted bioorthogonal reporter (LABOR) strategy for shuttling 9-azido sialic acid (9AzSia), a sialic acid reporter, into the brain to metabolically label sialoglycoconjugates, including sialylated glycoproteins and glycolipids. Subsequent bioorthogonal conjugation of the incorporated 9AzSia with fluorescent probes via click chemistry enabled fluorescence imaging of brain sialoglycans in living animals and in brain sections. Newly synthesized sialoglycans were found to widely distribute on neuronal cell surfaces, in particular at synaptic sites. Furthermore, large-scale proteomic profiling identified 140 brain sialylated glycoproteins, including a wealth of synapse-associated proteins. Finally, by performing a pulse−chase experiment, we showed that dynamic sialylation is spatially regulated, and that turnover of sialoglycans in the hippocampus is significantly slower than that in other brain regions. The LABOR strategy provides a means to directly visualize and monitor the sialoglycan biosynthesis in the mouse brain and will facilitate elucidating the functional role of brain sialylation. PMID:27125855

Brewing Science in the Chemistry Laboratory: A "Mashing" Investigation of Starch and Carbohydrates

ERIC Educational Resources Information Center

Pelter, Michael W.; McQuade, Jennifer

2005-01-01

The experiments that mimic the actual brewing process to explain the science to the nonscience majors is performed using malted barley as the source for both the starch and the amylase enzyme. The experiment introduces the concept of monitoring the progress of chemical reaction and was able to show the chemical breakdown of the starch to simple…

A century of progress in weed control in hardwood seedbeds

Treesearch

David B. South

2009-01-01

Weeds have existed in nurseries since before the time Bartram grew hardwoods during the 18th century. Hand weeding was the primary method of weed control during the first part of the 20th century. From 1931 to 1970, advances in chemistry increased the use of herbicides, and advances in engineering increased the reliance on machines for cultivation. Many managers now...

Annual Progress Report, FY 1980, 1 October 1979 - 30 September 1980,

DTIC Science & Technology

1980-10-01

coordinating an integrated pest management program, and constructing initial pilot prototypes, test models, and pro- ducing limited quantities of medical...Screening Test Based on the Ventilatory Responses of Fish . . . . . . . a & a . . . . 25 Chemistry and Molecular Biology of the Disinfection Process...Sink Unit, Surgical, Field (NSN 6545-00-935-4056), Engineering Evaluation of . . . . . . . . . . . . . . . . . . 69 Technical Feasibility Testing (TFT

Laboratory Directed Research and Development Annual Report for 2011

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hughes, Pamela J.

2012-04-09

This report documents progress made on all LDRD-funded projects during fiscal year 2011. The following topics are discussed: (1) Advanced sensors and instrumentation; (2) Biological Sciences; (3) Chemistry; (4) Earth and space sciences; (5) Energy supply and use; (6) Engineering and manufacturing processes; (7) Materials science and technology; (8) Mathematics and computing sciences; (9) Nuclear science and engineering; and (10) Physics.

The SDF1-CXCR4 Axis Functions through p38-MAPK Signaling to Drive Breast Cancer Progression and Metastasis

DTIC Science & Technology

2007-09-01

Duong, B.N., Melnik, L.I., Schief, L., Collins-Burow, B.M., Pace, D.K., McLachlan, J.A., Burow, M.E. Flavonoid Phytochemicals Regulate Activator... Chemistry . 10(7). 579-592. (2003). 17 Vanhoy, Lyndsay N. W81XWH-06-1-0694 BIOGRAPHICAL SKETCH NAME Lyndsay Vanhoy Rhodes POSITION

Taxonomy of economic seaweeds with reference to some pacific species. Volume 5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abbott, I.A.

1995-11-16

The series of workshops of which this one was part rests on the conviction that progress in seaweed aquaculture and marine natural products chemistry will advance appreciably once the taxonomy of commercially interesting species is better understood. California Sea Grant funded the first of these bienniel workshops more than a decade ago--in 1984, at the University of Guam.

Watershed monitoring and modelling and USA regulatory compliance.

PubMed

Turner, B G; Boner, M C

2004-01-01

The aim of the Columbus program was to implement a comprehensive watershed monitoring-network including water chemistry, aquatic biology and alternative sensors to establish water environment health and methods for determining future restoration progress and early warning for protection of drinking water supplies. The program was implemented to comply with USA regulatory requirements including Total Maximum Daily Load (TMDL) rules of the Clean Water Act (CWA) and Source Water Assessment and Protection (SWAP) rules under the Safe Drinking Water Act (SDWA). The USEPA Office of Research and Development and the Water Environment Research Foundation provided quality assurance oversight. The results obtained demonstrated that significant wet weather data is necessary to establish relationships between land use, water chemistry, aquatic biology and sensor data. These measurements and relationships formed the basis for calibrating the US EPA BASINS Model, prioritizing watershed health and determination of compliance with water quality standards. Conclusions specify priorities of cost-effective drainage system controls that attenuate stormwater flows and capture flushed pollutants. A network of permanent long-term real-time monitoring using combination of continuous sensor measurements, water column sampling and aquatic biology surveys and a regional organization is prescribed to protect drinking water supplies and measure progress towards water quality targets.

Recent Progress in SERS Biosensing

PubMed Central

Bantz, Kyle C.; Meyer, Audrey F.; Wittenberg, Nathan J.; Im, Hyungsoon; Kurtuluş, Özge; Lee, Si Hoon; Lindquist, Nathan C.

2011-01-01

This perspective gives an overview of recent developments in surface-enhanced Raman scattering (SERS) for biosensing. We focus this review on SERS papers published in the last 10 years and to specific applications of detecting biological analytes. Both intrinsic and extrinsic SERS biosensing schemes have been employed to detect and identify small molecules, nucleic acids, lipids, peptides, and proteins, as well as for in vivo and cellular sensing. Current SERS substrate technologies along with a series of advancements in surface chemistry, sample preparation, intrinsic/extrinsic signal transduction schemes, and tip-enhanced Raman spectroscopy are discussed. The progress covered herein shows great promise for widespread adoption of SERS biosensing. PMID:21509385

Progress in the chemistry of chromium(V) doping agents used in polarized target materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krumpolc, M.; Hill, D.; Struhrmann, H.B.

1990-01-01

We wish to report progress in two areas of the chromium (V)-based doping agents: Two commonly used chromium (V) complexes, I and II, have been synthesized in perdeuterated form (i.e., all hydrogens replaced by deuterium). They are sodium bis(2-ethyl-2-deuteroxy-butyrato)oxochromate(V)monodeuterate, IV, (acronym EDBA-Cr(V)), and sodium bis(2-deuteroxy-2-methylpropionato)oxochromate(V), III, (acronym DMPA-Cr(V)). A synthetic route leading to the preparation of stable, chromium(III)-free solutions of chromium(V) in diols (1,2-ethanediol/ethylene glycol/and 1,2-propanediol/propylene glycol/) has been outlined.

Progress in Preparation of Monodisperse Polymer Microspheres

NASA Astrophysics Data System (ADS)

Zhang, Hongyan

2017-12-01

The monodisperse crosslinked polymer microspheres have attracted much attention because of their superior thermal and solvent resistance, mechanical strength, surface activity and adsorption properties. They are of wide prospects for using in many fields such as biomedicine, electronic science, information technology, analytical chemistry, standard measurement and environment protection etc. Functional polymer microspheres prepared by different methods have the outstanding surface property, quantum size effect and good potential future in applications with its designable structure, controlled size and large ratio of surface to volume. Scholars of all over the world have focused on this hot topic. The preparation method and research progress in functional polymer microspheres are addressed in the paper.

Computationally Efficient Modeling of Hydrocarbon Oxidation Chemistry and Flames Using Constituents and Species

DTIC Science & Technology

2012-02-10

1 Nc X l Dil bNl = 1 Nc X l Dil ÃX k bClkNk! . (19) Finally, it is necessary to compute, from the Dil coefficients, a global diffusion coefficient...exists a mole fraction XCk such that Nk ’ NcXCk. Therefore, X l,k Dil bClk XCk = 1 Nc X l Dil bNl = 1 Nc X l Dil ÃX k bClkNk! . (20) Finally, it is

Adaptive Optics for the Thirty Meter Telescope

NASA Astrophysics Data System (ADS)

Ellerbroek, Brent

2013-12-01

This paper provides an overview of the progress made since the last AO4ELT conference towards developing the first-light AO architecture for the Thirty Meter Telescope (TMT). The Preliminary Design of the facility AO system NFIRAOS has been concluded by the Herzberg Institute of Astrophysics. Work on the client Infrared Imaging Spectrograph (IRIS) has progressed in parallel, including a successful Conceptual Design Review and prototyping of On-Instrument WFS (OIWFS) hardware. Progress on the design for the Laser Guide Star Facility (LGSF) continues at the Institute of Optics and Electronics in Chengdu, China, including the final acceptance of the Conceptual Design and modest revisions for the updated TMT telescope structure. Design and prototyping activities continue for lasers, wavefront sensing detectors, detector readout electronics, real-time control (RTC) processors, and deformable mirrors (DMs) with their associated drive electronics. Highlights include development of a prototype sum frequency guide star laser at the Technical Institute of Physics and Chemistry (Beijing); fabrication/test of prototype natural- and laser-guide star wavefront sensor CCDs for NFIRAOS by MIT Lincoln Laboratory and W.M. Keck Observatory; a trade study of RTC control algorithms and processors, with prototyping of GPU and FPGA architectures by TMT and the Dominion Radio Astrophysical Observatory; and fabrication/test of a 6x60 actuator DM prototype by CILAS. Work with the University of British Columbia LIDAR is continuing, in collaboration with ESO, to measure the spatial/temporal variability of the sodium layer and characterize the sodium coupling efficiency of several guide star laser systems. AO performance budgets have been further detailed. Modeling topics receiving particular attention include performance vs. computational cost tradeoffs for RTC algorithms; optimizing performance of the tip/tilt, plate scale, and sodium focus tracking loops controlled by the NGS on-instrument wavefront sensors, sky coverage, PSF reconstruction for LGS MCAO, and precision astrometry for the galactic center and other observations.

Progression of trunk imbalance in adolescent idiopathic scoliosis with a thoracolumbar/lumbar curve: is it predictable at the initial visit?

PubMed

Hwang, Chang Ju; Lee, Choon Sung; Lee, Dong-Ho; Cho, Jae Hwan

2017-11-01

OBJECTIVE Progression of trunk imbalance is an important finding during follow-up of patients with adolescent idiopathic scoliosis (AIS). Nevertheless, no factors that predict progression of trunk imbalance have been identified. The purpose of this study was to identify parameters that predict progression of trunk imbalance in cases of AIS with a structural thoracolumbar/lumbar (TL/L) curve. METHODS This study included 105 patients with AIS and a structural TL/L curve who were followed up at an outpatient clinic. Patients with trunk imbalance (trunk shift ≥ 20 mm) at the initial visit were excluded. All patients were followed up for more than 2 years. Patients were divided into the following groups according to progression of trunk imbalance: 1) Group P, trunk shift ≥ 20 mm at the final visit and degree of progression ≥ 10 mm; and 2) Group NP, trunk shift < 20 mm at the final visit or degree of progression < 10 mm. Radiological parameters included Cobb angle, upper end vertebrae and lower end vertebrae (LEV), LEV tilt, disc wedge angle between LEV and LEV+1, trunk shift, apical vertebral translation, and apical vertebral rotation (AVR). Each parameter was compared between groups. Radiological parameters were assessed at every visit using whole-spine standing anteroposterior radiographs. RESULTS Among the 105 patients examined, 13 showed trunk imbalance with progression ≥ 10 mm at the final visit (Group P). Multivariate logistic regression analysis identified a lower Risser grade (p = 0.002) and a greater initial AVR (p = 0.020) as predictors of progressive trunk imbalance. A change in LEV tilt during follow-up was associated with trunk imbalance (p = 0.001). CONCLUSIONS Risser grade and AVR measured at the initial visit may predict progression of trunk imbalance. Surgeons should consider the risk of progressive trunk imbalance if patients show skeletal immaturity and a greater AVR at the initial visit.

Final Technical Progress Report: Development of Low-Cost Suspension Heliostat; December 7, 2011 - December 6, 2012

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bender, W.

2013-01-01

Final technical progress report of SunShot Incubator Solaflect Energy. The project succeeded in demonstrating that the Solaflect Suspension Heliostat design is viable for large-scale CSP installations. Canting accuracy is acceptable and is continually improving as Solaflect improves its understanding of this design. Cost reduction initiatives were successful, and there are still many opportunities for further development and further cost reduction.

Study and modeling of finite rate chemistry effects in turbulent non-premixed flames

NASA Technical Reports Server (NTRS)

Vervisch, Luc

1993-01-01

The development of numerical models that reflect some of the most important features of turbulent reacting flows requires information about the behavior of key quantities in well defined combustion regimes. In turbulent flames, the coupling between turbulent and chemical processes is so strong that it is extremely difficult to isolate the role played by one individual physical phenomenon. Direct numerical simulation (hereafter DNS) allows us to study in detail the turbulence-chemistry interaction in some restricted but completely defined situations. Globally, non-premixed flames are controlled by two limiting regimes: the fast chemistry case, where the turbulent flame can be pictured as a random distribution of local chemical equilibrium problems; and the slow chemistry case, where the chemistry integrates in time the turbulent fluctuations. The Damkoehler number, ratio of a mechanical time scale to chemical time scale, is used to distinguish between these regimes. Today most of the industrial computer codes are able to perform predictions in the hypothesis of local equilibrium chemistry using a presumed shape for the probability density function (pdt) of the conserved scalar. However, the finite rate chemistry situation is of great interest because industrial burners usually generate regimes in which, at some points, the flame is undergoing local extinction or at least non-equilibrium situations. Moreover, this variety of situations strongly influences the production of pollutants. To quantify finite rate chemistry effect, the interaction between a non-premixed flame and a free decaying turbulence is studied using DNS. The attention is focused on the dynamic of extinction, and an attempt is made to quantify the effect of the reaction on the small scale mixing process. The unequal diffusivity effect is also addressed. Finally, a simple turbulent combustion model based on the DNS observations and tractable in real flow configurations is proposed.

Comparison of student success using "atoms first" versus "traditional" curricula

NASA Astrophysics Data System (ADS)

Hillesheim, Christina S.

The purpose of this study was to investigate the difference between the "atoms first" and the "traditional" curricula. Specifically focusing on which curriculum better aligns to curricular expectations, leads to higher student success when students are grouped together, and when students are differentiated based on several factors. The main difference between the two approaches being the sequence of topics presented in the first semester general chemistry course. This study involves more than 9,500 general chemistry I and II students over 7 semesters with about half of them being taught using the "atoms first" approach. Student success was measured using the American Chemical Society's (ACS) final examination scores and the final letter grades. Alignment to curricular expectations was determined via a qualitative review of textbooks written for each of the approaches. This showed that the "atoms first" approach better aligns to research supported best practices. An analysis of covariance (ANCOVA) was performed to determine if there is a significant difference between the "atoms first" and the "traditional" curricula. The "traditional" approach was found to lead to higher student achievement for both measures of student success in both chemistry I and II courses. Lastly, multiple linear, multinomial logistic, and binary logistic regressions were run using all of the subgroups---gender, race/ethnicity, major, ACT composite, math ACT, overall GPA, and classroom size---as predictor variables to determine if any significant interactions between the curricular methods and the different subgroups existed. Results found that the relationship between gender, GPA, and classroom size groupings significantly impact student achievement in general chemistry. Specifically, the "traditional" approach lead to higher student success compared to the "atoms first" approach for males, females, below average GPA students, above average GPA students, and students in large classroom settings. However, there are several factors---final examination content, new teacher impact, teacher's view of science, and withdrawal rate and timing---that need to be taken into account when implementing these findings. Overall, the results of this study provides a cautionary reminder of the many impacts affecting curriculum implementation and the importance of professional development and training during a curriculum transitional period.

7 CFR 3402.23 - Documentation of progress on funded projects.

Code of Federal Regulations, 2011 CFR

2011-01-01

... the academic program due to unsatisfactory academic progress; or voluntarily withdraws from the Fellowship or the academic program. If a Fellow has not completed all degree requirements at the end of the... database contains narrative project information, progress/impact statements, and final technical reports...

7 CFR 3402.23 - Documentation of progress on funded projects.

Code of Federal Regulations, 2014 CFR

2014-01-01

... the academic program due to unsatisfactory academic progress; or voluntarily withdraws from the Fellowship or the academic program. If a Fellow has not completed all degree requirements at the end of the... database contains narrative project information, progress/impact statements, and final technical reports...

7 CFR 3402.23 - Documentation of progress on funded projects.

Code of Federal Regulations, 2012 CFR

2012-01-01

... the academic program due to unsatisfactory academic progress; or voluntarily withdraws from the Fellowship or the academic program. If a Fellow has not completed all degree requirements at the end of the... database contains narrative project information, progress/impact statements, and final technical reports...

7 CFR 3402.23 - Documentation of progress on funded projects.

Code of Federal Regulations, 2013 CFR

2013-01-01

... the academic program due to unsatisfactory academic progress; or voluntarily withdraws from the Fellowship or the academic program. If a Fellow has not completed all degree requirements at the end of the... database contains narrative project information, progress/impact statements, and final technical reports...

Mathematics and Statistics Research Department progress report, period ending June 30, 1982

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denson, M.V.; Funderlic, R.E.; Gosslee, D.G.

1982-08-01

This report is the twenty-fifth in the series of progress reports of the Mathematics and Statistics Research Department of the Computer Sciences Division, Union Carbide Corporation Nuclear Division (UCC-ND). Part A records research progress in analysis of large data sets, biometrics research, computational statistics, materials science applications, moving boundary problems, numerical linear algebra, and risk analysis. Collaboration and consulting with others throughout the UCC-ND complex are recorded in Part B. Included are sections on biology, chemistry, energy, engineering, environmental sciences, health and safety, materials science, safeguards, surveys, and the waste storage program. Part C summarizes the various educational activities inmore » which the staff was engaged. Part D lists the presentations of research results, and Part E records the staff's other professional activities during the report period.« less

Mathematics and statistics research department. Progress report, period ending June 30, 1981

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lever, W.E.; Kane, V.E.; Scott, D.S.

1981-09-01

This report is the twenty-fourth in the series of progress reports of the Mathematics and Statistics Research Department of the Computer Sciences Division, Union Carbide Corporation - Nuclear Division (UCC-ND). Part A records research progress in biometrics research, materials science applications, model evaluation, moving boundary problems, multivariate analysis, numerical linear algebra, risk analysis, and complementary areas. Collaboration and consulting with others throughout the UCC-ND complex are recorded in Part B. Included are sections on biology and health sciences, chemistry, energy, engineering, environmental sciences, health and safety research, materials sciences, safeguards, surveys, and uranium resource evaluation. Part C summarizes the variousmore » educational activities in which the staff was engaged. Part D lists the presentations of research results, and Part E records the staff's other professional activities during the report period.« less

Modification of heterogeneous chemistry by complex substrate morphology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henson, B.F.; Buelow, S.J.; Robinson, J.M.

1998-12-31

This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Chemistry in many environmental systems is determined at some stage by heterogeneous reaction with a surface. Typically the surface exists as a dispersion or matrix of particulate matter or pores, and a determination of the heterogeneous chemistry of the system must address the extent to which the complexity of the environmental surface affects the reaction rates. Reactions that are of current interest are the series of chlorine nitrate reactions important in polar ozone depletion. The authors have applied surfacemore » spectroscopic techniques developed at LANL to address the chemistry of chlorine nitrate reactions on porous nitric and sulfuric acid ice surfaces as a model study of the measurement of complex, heterogeneous reaction rates. The result of the study is an experimental determination of the surface coverage of one adsorbed reagent and a mechanism of reactivity based on the dependence of this coverage on temperature and vapor pressure. The resulting mechanism allows the first comprehensive modeling of chlorine nitrate reaction probability data from several laboratories.« less

Batteries at NASA - Today and Beyond

NASA Technical Reports Server (NTRS)

Reid, Concha M.

2015-01-01

NASA uses batteries for virtually all of its space missions. Batteries can be bulky and heavy, and some chemistries are more prone to safety issues than others. To meet NASA's needs for safe, lightweight, compact and reliable batteries, scientists and engineers at NASA develop advanced battery technologies that are suitable for space applications and that can satisfy these multiple objectives. Many times, these objectives compete with one another, as the demand for more and more energy in smaller packages dictates that we use higher energy chemistries that are also more energetic by nature. NASA partners with companies and universities, like Xavier University of Louisiana, to pool our collective knowledge and discover innovative technical solutions to these challenges. This talk will discuss a little about NASA's use of batteries and why NASA seeks more advanced chemistries. A short primer on battery chemistries and their chemical reactions is included. Finally, the talk will touch on how the work under the Solid High Energy Lithium Battery (SHELiB) grant to develop solid lithium-ion conducting electrolytes and solid-state batteries can contribute to NASA's mission.

Cloud Chemistry in the United States: Problems and Prospects

NASA Astrophysics Data System (ADS)

Carlton, A. G.; Barth, M. C.; Lance, S.; Fahey, K.; McNeill, V. F.; Weber, R. J.

2017-12-01

Clouds cover 60% of the Earth's surface at a given time and are the primary means by which atmospheric trace species are lofted from the polluted boundary layer to the free troposphere. Clouds also play an important role as atmospheric aqueous phase reactors, scavenging soluble gas phase precursors and providing a medium for oxidation reactions that yield lower volatility products that contribute to increased aerosol mass when cloud drops evaporate. On a global average, most sulfate particles are formed during cloud processing, and organic particles known to form through aqueous phase pathways are found above clouds. However, atmospheric chemistry observations are generally biased for clear sky conditions. For example, aircraft field deployments typically avoid clouds. Satellite retrievals impacted by clouds are often screened from the final data products. This hinders knowledge of cloud chemistry and the impacts on tropospheric composition. In this work, we explore temporal and geospatial trends in trace species related to cloud processing in the U.S. with a focus on organic chemistry. We apply 3-dimensional and 0-dimensional models to recent campaigns and mountaintop cloud sampling sites, and compare to measurements.

Evaluating the Success of Hispanic-Surname Students in First-Semester General Chemistry

NASA Astrophysics Data System (ADS)

Mason, Diana; Mittag, Kathleen C.

2001-02-01

This study was undertaken to identify methods and variables that affect classroom instruction, student achievement, and retention in a first-semester general chemistry course at a designated minority (primarily Hispanic) public institution of higher education. The course was a large-group lecture class (n = 241) of first-semester general chemistry that included 92 students with Hispanic surnames. Background information was gathered on the students' university-required entrance examinations, results from a logical thinking ability test, and scores from an instructor-developed diagnostic pretest. Ethnicity and gender data were collected and evaluated for trends that might affect students' success in chemistry achievement. Sixteen (17 percent) of the Hispanic-surname students enrolled in this class participated in a one-hour-per-week recitation session. The data indicate that university mathematics level is a strong predictor of success regardless of ethnicity, gender, or pre-course achievement variables, and participation in recitation sessions also improved course averages for all student groups. Included in the final analysis of this study are the benefits that can be attributed to good counseling.

See Correction to this article.

Chemistry in CESM-SE: Evaluation, Performance and Optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lamarque, Jean-Francois; Conley, Andrew; Vitt, Francis

2016-01-06

The purpose of the proposed work focused on development of chemistry representation within the Spectral Element (SE) dynamical core as implemented in the Community Earth System Model (CESM). More specifically, a main focus was on the ability of SE to accurately represent tracer transport. The proposed approach was to incrementally increase the complexity of the problem, starting from specified two-dimensional flow and tracers to simulations using specified dynamics and full chemistry. As demonstrated below, we have successfully studied all aspects of the proposed work, although only part of the work has been published in the refereed literature so far. Furthermore,more » because the SE dynamical core has been found to have several deficiencies that are still being investigated for solution, not all proposed tasks were finalized. In addition to the tests for SE performance, in an effort to decrease the computational burden of interactive chemistry, especially in the case of a large number of chemical species and chemical reactions, development on a faster chemical solver and implementation on GPUs has been implemented in CESM under the leadership of John Drake (U. Tennessee).« less

The Contributions of Chemistry and Transport to Low Arctic Ozone in March 2011 Derived from Aura MLS Observations

NASA Technical Reports Server (NTRS)

Strahan, S. E.; Douglass, A. R.; Newman, P. A.

2012-01-01

Stratospheric and total columns of Arctic O3 (63-90 N) in late March 2011 averaged 320 and 349 DU, respectively. These values are 74 DU lower than averages for the previous 6 years. We use Aura MLS O3 observations to quantify the roles of chemistry and transport and find there are two major reasons for low O3 in March 2011: heterogeneous chemical loss and a late final warming that delayed the resupply of O3 until April. Daily vortex-averaged partial columns in the lowermost stratosphere (p greater than 133 hPa) and middle stratosphere (p less than 29 hPa) are unaffected by local heterogeneous chemistry and show a near total lack of transport into the vortex between late January and late March, contributing to the observed low column. The lower stratospheric (LS) column (133-29 hPa) is affected by both heterogeneous chemistry and transport. Low interannual variability of Aura MLS 0 3 columns and temperature inside the Arctic vortex (2004-2011) shows that the transport contribution to vortex O3 in fall and early winter is nearly the same each year. The descent of MLS N2O vortex profiles in 2011 provides an estimate of O3 transported into the LS column during late winter. By quantifying the role of transport we determine that PSC-driven chemical loss causes 80 (plus or minus 10) DU of vortex-averaged O3 loss by late March 2011. Without heterogeneous chemical loss, March 2011 vortex O3 would have been 40 DU lower than normal due to the late final warming and resupply of O3 which did not occur until April.

Expanding GREENSCOPE beyond the Gate: A Green Chemistry and Life-Cycle Perspective

EPA Science Inventory

Industrial processes, particularly those within the chemical industry, contribute products and services to improve and increase society’s quality of life. However, the transformation of raw materials into their respective final goods involves the consumption of mass and energy an...

Cooperative studyware development of organic chemistry module by experts, teachers, and students

NASA Astrophysics Data System (ADS)

Dori, Yehudit J.

1995-06-01

Experts, teachers, and students took active part in a process of organic chemistry studyware development. A unique characteristic of this process was the active involvement of three different groups of people in the authoring process: science educators, chemistry teachers, and chemistry students studying towards an education certificate. The science educators—the experts—advised the team on new methods of presenting the subject matter in an appealing way, using 3D computerized molecular modeling. The in-service chemistry teachers contributed from their rich field experience to constructing the studyware. This mutual development helped maintain the balance between expert requirements and expectations from students on one hand, and the actual student capabilities, as perceived by teachers through constant contact with the students, on the other. Finally, the preservice teachers—the undergraduate chemistry students—were often zealous, enthusiastic, and willing to put in the extra time and effort needed to produce quality studyware, while following the guidelines of the experts and teachers. Feedback on the qualities and shortcomings of the studyware was obtained in two cycles. The first one was done while the studyware was still under development by peers, and the second by individual target students, serving as a beta-site. This double feedback helped improve the studyware, mainly by elaborating on portions that require more detail and explanation. The paper describes the process as well as representative parts of the studyware. The combination of experts, teachers, and students in the development team seems to have the potential to yield studyware that is appropriate for effective science education in general and chemistry teaching in particular.

Large eddy simulation of turbulent premixed combustion using tabulated detailed chemistry and presumed probability density function

NASA Astrophysics Data System (ADS)

Zhang, Hongda; Han, Chao; Ye, Taohong; Ren, Zhuyin

2016-03-01

A method of chemistry tabulation combined with presumed probability density function (PDF) is applied to simulate piloted premixed jet burner flames with high Karlovitz number using large eddy simulation. Thermo-chemistry states are tabulated by the combination of auto-ignition and extended auto-ignition model. To evaluate the predictive capability of the proposed tabulation method to represent the thermo-chemistry states under the condition of different fresh gases temperature, a-priori study is conducted by performing idealised transient one-dimensional premixed flame simulations. Presumed PDF is used to involve the interaction of turbulence and flame with beta PDF to model the reaction progress variable distribution. Two presumed PDF models, Dirichlet distribution and independent beta distribution, respectively, are applied for representing the interaction between two mixture fractions that are associated with three inlet streams. Comparisons of statistical results show that two presumed PDF models for the two mixture fractions are both capable of predicting temperature and major species profiles, however, they are shown to have a significant effect on the predictions for intermediate species. An analysis of the thermo-chemical state-space representation of the sub-grid scale (SGS) combustion model is performed by comparing correlations between the carbon monoxide mass fraction and temperature. The SGS combustion model based on the proposed chemistry tabulation can reasonably capture the peak value and change trend of intermediate species. Aspects regarding model extensions to adequately predict the peak location of intermediate species are discussed.

NOx Emissions from a Rotating Detonation-wave Engine

NASA Astrophysics Data System (ADS)

Kailasanath, Kazhikathra; Schwer, Douglas

2016-11-01

Rotating detonation-wave engines (RDE) are a form of continuous detonation-wave engines. They potentially provide further gains in performance than an intermittent or pulsed detonation-wave engine (PDE). The overall flow field in an idealized RDE, primarily consisting of two concentric cylinders, has been discussed in previous meetings. Because of the high pressures involved and the lack of adequate reaction mechanisms for this regime, previous simulations have typically used simplified chemistry models. However, understanding the exhaust species concentrations in propulsion devices is important for both performance considerations as well as estimating pollutant emissions. Progress towards addressing this need will be discussed in this talk. In this approach, an induction parameter model is used for simulating the detonation but a more detailed finite-chemistry model including NOx chemistry is used in the expansion flow region, where the pressures are lower and the uncertainties in the chemistry model are greatly reduced. Results show that overall radical concentrations in the exhaust flow are substantially lower than from earlier predictions with simplified models. Results to date show that NOx emissions are not a problem for the RDE due to the short residence times and the nature of the flow field. Furthermore, simulations show that the amount of NOx can be further reduced by tailoring the fluid dynamics within the RDE.

High-pressure alchemy on a small-pore zeolite

NASA Astrophysics Data System (ADS)

Lee, Y.

2011-12-01

While an ever-expanding variety of zeolites with a wide range of framework topology is available, it is desirable to have a way to tailor the chemistry of the zeolitic nanopores for a given framework topology via controlling both the coordination-inclusion chemistry and framework distortion/relaxation. This is, however, subjected to the ability of a zeolitic nanopore to allow the redistribution of cations-water assembly and/or insertion of foreign molecules into the pores and channels. Small-pore zeolites such as natrolite (Na16Al16Si24O80x16H2O), however, have been known to show very limited capacity for any changes in the confinement chemistry. We have recently shown that various cation-exchanged natrolites can be prepared under modest conditions from natural sodium natrolite and exhibit cation-dependent volume expansions by up to 18.5% via converting the elliptical channels into progressively circular ones. Here, we show that pressure can be used as a unique and clean tool to further manipulate the chemistry of the natrolite nanopores. Our recent crystallographic and spectroscopic studies of pressure-insertion of foreign molecules, trivalent-cation exchange under pressure, and pressure-induced inversion of cation-water coordination and pore geometry in various cation-exchanged natrolites will be presented.

The Chemistry of Shocked High-energy Materials: Connecting Atomistic Simulations to Experiments

NASA Astrophysics Data System (ADS)

Islam, Md Mahbubul; Strachan, Alejandro

2017-06-01

A comprehensive atomistic-level understanding of the physics and chemistry of shocked high energy (HE) materials is crucial for designing safe and efficient explosives. Advances in the ultrafast spectroscopy and laser shocks enabled the study of shock-induced chemistry at extreme conditions occurring at picosecond timescales. Despite this progress experiments are not without limitations and do not enable a direct characterization of chemical reactions. At the same time, large-scale reactive molecular dynamics (MD) simulations are capable of providing description of the shocked-induced chemistry but the uncertainties resulting from the use of approximate descriptions of atomistic interactions remain poorly quantified. We use ReaxFF MD simulations to investigate the shock and temperature induced chemical decomposition mechanisms of polyvinyl nitrate, RDX, and nitromethane. The effect of various shock pressures on reaction initiation mechanisms is investigated for all three materials. We performed spectral analysis from atomistic velocities at different shock pressures to enable direct comparison with experiments. The simulations predict volume-increasing reactions at the shock-to-detonation transitions and the shock vs. particle velocity data are in good agreement with available experimental data. The ReaxFF MD simulations validated against experiments enabled prediction of reaction kinetics of shocked materials, and interpretation of experimental spectroscopy data via assignment of the spectral peaks to dictate various reaction pathways at extreme conditions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, D.W.; Boparai, A.S.; Bowers, D.L.

This report summarizes the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year (FY) 2000 (October 1999 through September 2000). This annual progress report, which is the seventeenth in this series for the ACL, describes effort on continuing projects, work on new projects, and contributions of the ACL staff to various programs at ANL. The ACL operates within the ANL system as a full-cost-recovery service center, but it has a mission that includes a complementary research and development component: The Analytical Chemistry Laboratory will provide high-quality, cost-effective chemical analysis and related technical support tomore » solve research problems of our clients--Argonne National Laboratory, the Department of Energy, and others--and will conduct world-class research and development in analytical chemistry and its applications. The ACL handles a wide range of analytical problems that reflects the diversity of research and development (R&D) work at ANL. Some routine or standard analyses are done, but the ACL operates more typically in a problem-solving mode in which development of methods is required or adaptation of techniques is needed to obtain useful analytical data. The ACL works with clients and commercial laboratories if a large number of routine analyses are required. Much of the support work done by the ACL is very similar to applied analytical chemistry research work.« less

Creating a dashboard to track progress toward IOM recommendations for the future of nursing.

PubMed

Spetz, Joanne; Bates, Timothy; Chu, Lela; Lin, Jessica; Fishman, Nancy W; Melichar, Lori

2013-01-01

This article explains the process used to identify and develop a set of data used to track national progress toward the recommendations of the Institute of Medicine Committee for the Future of Nursing. The data are presented in a dashboard format to visually summarize information and quickly measure progress. The approach selected by the research team is outlined, the criteria for selecting candidate metrics are detailed, the process for seeking external guidance is described, and the final dashboard measures are presented. Finally, the methods for data collection for each metric are explicated, to guide states and local regions in the collection of their own data.

Student Perceptions of Online Homework Use for Formative Assessment of Learning in Organic Chemistry.

PubMed

Richards-Babb, Michelle; Curtis, Reagan; Georgieva, Zomitsa; Penn, John H

2015-11-10

Use of online homework as a formative assessment tool for organic chemistry coursework was examined. Student perceptions of online homework in terms of (i) its ranking relative to other course aspects, (ii) their learning of organic chemistry, and (iii) whether it improved their study habits and how students used it as a learning tool were investigated. Our students perceived the online homework as one of the more useful course aspects for learning organic chemistry content. We found a moderate and statistically significant correlation between online homework performance and final grade. Gender as a variable was ruled out since significant gender differences in overall attitude toward online homework use and course success rates were not found. Our students expressed relatively positive attitudes toward use of online homework with a majority indicating improved study habits (e.g., study in a more consistent manner). Our students used a variety of resources to remediate incorrect responses (e.g., class materials, general online materials, and help from others). However, 39% of our students admitted to guessing at times, instead of working to remediate incorrect responses. In large enrollment organic chemistry courses, online homework may act to bridge the student-instructor gap by providing students with a supportive mechanism for regulated learning of content.

Improving chemical education from high school to college using a more hands-on approach

NASA Astrophysics Data System (ADS)

Ruddick, Kristie Winfield

In this work, various alternative teaching methods and activities for chemical education are developed, presented, and evaluated. In the first study, an original hands-on activity using LEGO® blocks to model ionic chemical formulas is presented together with quantitative and qualitative data regarding its educational effectiveness. Students explore cation to anion ratios using LEGO® blocks to represent trivalent, divalent and monovalent cations and anions. High school chemistry students who participated in the LEGO® lab showed significantly higher post-test scores than other students. The second study grows out of the creation of a computational lab module that is shown to significantly increase student learning in the subject of molecular orbital theory in first semester college General Chemistry. The third and final study presented is a course redesign project for college CHEM 1100, Preparation for General Chemistry. In this project the classroom is “flipped”. Students watch video lectures at home, and spend class time working with peers and the instructor on problem solving activities. The results presented here are one of the first quantitative studies showing the effectiveness of “flipping the classroom”. Students who were taught using the Reverse-Instruction (RI) method had significantly higher success in both the Preparation for General Chemistry course and traditionally taught General Chemistry I the following semester.

A localized model of spatial cognition in chemistry

NASA Astrophysics Data System (ADS)

Stieff, Mike

This dissertation challenges the assumption that spatial cognition, particularly visualization, is the key component to problem solving in chemistry. In contrast to this assumption, I posit a localized, or task-specific, model of spatial cognition in chemistry problem solving to locate the exact tasks in a traditional organic chemistry curriculum that require students to use visualization strategies to problem solve. Instead of assuming that visualization is required for most chemistry tasks simply because chemistry concerns invisible three-dimensional entities, I instead use the framework of the localized model to identify how students do and do not make use of visualization strategies on a wide variety of assessment tasks regardless of each task's explicit demand for spatial cognition. I establish the dimensions of the localized model with five studies. First, I designed two novel psychometrics to reveal how students selectively use visualization strategies to interpret and analyze molecular structures. The third study comprised a document analysis of the organic chemistry assessments that empirically determined only 12% of these tasks explicitly require visualization. The fourth study concerned a series of correlation analyses between measures of visuo-spatial ability and chemistry performance to clarify the impact of individual differences. Finally, I performed a series of micro-genetic analyses of student problem solving that confirmed the earlier findings and revealed students prefer to visualize molecules from alternative perspectives without using mental rotation. The results of each study reveal that occurrences of sophisticated spatial cognition are relatively infrequent in chemistry, despite instructors' ostensible emphasis on the visualization of three-dimensional structures. To the contrary, students eschew visualization strategies and instead rely on the use of molecular diagrams to scaffold spatial cognition. Visualization does play a key role, however, in problem solving on a select group of chemistry tasks that require students to translate molecular representations or fundamentally alter the morphology of a molecule. Ultimately, this dissertation calls into question the assumption that individual differences in visuo-spatial ability play a critical role in determining who succeeds in chemistry. The results of this work establish a foundation for defining the precise manner in which visualization tools can best support problem solving.

Final Report: Ionization chemistry of high temperature molecular fluids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fried, L E

2007-02-26

With the advent of coupled chemical/hydrodynamic reactive flow models for high explosives, understanding detonation chemistry is of increasing importance to DNT. The accuracy of first principles detonation codes, such as CHEETAH, are dependent on an accurate representation of the species present under detonation conditions. Ionic species and non-molecular phases are not currently included coupled chemistry/hydrodynamic simulations. This LDRD will determine the prevalence of such species during high explosive detonations, by carrying out experimental and computational investigation of common detonation products under extreme conditions. We are studying the phase diagram of detonation products such as H{sub 2}O, or NH{sub 3} andmore » mixtures under conditions of extreme pressure (P > 1 GPa) and temperature (T > 1000K). Under these conditions, the neutral molecular form of matter transforms to a phase dominated by ions. The phase boundaries of such a region are unknown.« less

Tools, techniques, organisation and culture of the CADD group at Sygnature Discovery.

PubMed

St-Gallay, Steve A; Sambrook-Smith, Colin P

2017-03-01

Computer-aided drug design encompasses a wide variety of tools and techniques, and can be implemented with a range of organisational structures and focus in different organisations. Here we outline the computational chemistry skills within Sygnature Discovery, along with the software and hardware at our disposal, and briefly discuss the methods that are not employed and why. The goal of the group is to provide support for design and analysis in order to improve the quality of compounds synthesised and reduce the timelines of drug discovery projects, and we reveal how this is achieved at Sygnature. Impact on medicinal chemistry is vital to demonstrating the value of computational chemistry, and we discuss the approaches taken to influence the list of compounds for synthesis, and how we recognise success. Finally we touch on some of the areas being developed within the team in order to provide further value to the projects and clients.

Applying green chemistry to the photochemical route to artemisinin

NASA Astrophysics Data System (ADS)

Amara, Zacharias; Bellamy, Jessica F. B.; Horvath, Raphael; Miller, Samuel J.; Beeby, Andrew; Burgard, Andreas; Rossen, Kai; Poliakoff, Martyn; George, Michael W.

2015-06-01

Artemisinin is an important antimalarial drug, but, at present, the environmental and economic costs of its semi-synthetic production are relatively high. Most of these costs lie in the final chemical steps, which follow a complex acid- and photo-catalysed route with oxygenation by both singlet and triplet oxygen. We demonstrate that applying the principles of green chemistry can lead to innovative strategies that avoid many of the problems in current photochemical processes. The first strategy combines the use of liquid CO2 as solvent and a dual-function solid acid/photocatalyst. The second strategy is an ambient-temperature reaction in aqueous mixtures of organic solvents, where the only inputs are dihydroartemisinic acid, O2 and light, and the output is pure, crystalline artemisinin. Everything else—solvents, photocatalyst and aqueous acid—can be recycled. Some aspects developed here through green chemistry are likely to have wider application in photochemistry and other reactions.

Quo vadis, analytical chemistry?

PubMed

Valcárcel, Miguel

2016-01-01

This paper presents an open, personal, fresh approach to the future of Analytical Chemistry in the context of the deep changes Science and Technology are anticipated to experience. Its main aim is to challenge young analytical chemists because the future of our scientific discipline is in their hands. A description of not completely accurate overall conceptions of our discipline, both past and present, to be avoided is followed by a flexible, integral definition of Analytical Chemistry and its cornerstones (viz., aims and objectives, quality trade-offs, the third basic analytical reference, the information hierarchy, social responsibility, independent research, transfer of knowledge and technology, interfaces to other scientific-technical disciplines, and well-oriented education). Obsolete paradigms, and more accurate general and specific that can be expected to provide the framework for our discipline in the coming years are described. Finally, the three possible responses of analytical chemists to the proposed changes in our discipline are discussed.

Colloidal characterization of silicon nitride and silicon carbide

NASA Technical Reports Server (NTRS)

Feke, Donald L.

1986-01-01

The colloidal behavior of aqueous ceramic slips strongly affects the forming and sintering behavior and the ultimate mechanical strength of the final ceramic product. The colloidal behavior of these materials, which is dominated by electrical interactions between the particles, is complex due to the strong interaction of the solids with the processing fluids. A surface titration methodology, modified to account for this interaction, was developed and used to provide fundamental insights into the interfacial chemistry of these systems. Various powder pretreatment strategies were explored to differentiate between true surface chemistry and artifacts due to exposure history. The colloidal behavior of both silicon nitride and carbide is dominated by silanol groups on the powder surfaces. However, the colloid chemistry of silicon nitride is apparently influenced by an additional amine group. With the proper powder treatments, silicon nitride and carbide powder can be made to appear colloidally equivalent. The impact of these results on processing control will be discussed.

Applying green chemistry to the photochemical route to artemisinin.

PubMed

Amara, Zacharias; Bellamy, Jessica F B; Horvath, Raphael; Miller, Samuel J; Beeby, Andrew; Burgard, Andreas; Rossen, Kai; Poliakoff, Martyn; George, Michael W

2015-06-01

Artemisinin is an important antimalarial drug, but, at present, the environmental and economic costs of its semi-synthetic production are relatively high. Most of these costs lie in the final chemical steps, which follow a complex acid- and photo-catalysed route with oxygenation by both singlet and triplet oxygen. We demonstrate that applying the principles of green chemistry can lead to innovative strategies that avoid many of the problems in current photochemical processes. The first strategy combines the use of liquid CO2 as solvent and a dual-function solid acid/photocatalyst. The second strategy is an ambient-temperature reaction in aqueous mixtures of organic solvents, where the only inputs are dihydroartemisinic acid, O2 and light, and the output is pure, crystalline artemisinin. Everything else-solvents, photocatalyst and aqueous acid-can be recycled. Some aspects developed here through green chemistry are likely to have wider application in photochemistry and other reactions.

Tools, techniques, organisation and culture of the CADD group at Sygnature Discovery

NASA Astrophysics Data System (ADS)

St-Gallay, Steve A.; Sambrook-Smith, Colin P.

2017-03-01

Computer-aided drug design encompasses a wide variety of tools and techniques, and can be implemented with a range of organisational structures and focus in different organisations. Here we outline the computational chemistry skills within Sygnature Discovery, along with the software and hardware at our disposal, and briefly discuss the methods that are not employed and why. The goal of the group is to provide support for design and analysis in order to improve the quality of compounds synthesised and reduce the timelines of drug discovery projects, and we reveal how this is achieved at Sygnature. Impact on medicinal chemistry is vital to demonstrating the value of computational chemistry, and we discuss the approaches taken to influence the list of compounds for synthesis, and how we recognise success. Finally we touch on some of the areas being developed within the team in order to provide further value to the projects and clients.

The halogen bond: Nature and applications

NASA Astrophysics Data System (ADS)

Costa, Paulo J.

2017-10-01

The halogen bond, corresponding to an attractive interaction between an electrophilic region in a halogen (X) and a nucleophile (B) yielding a R-X⋯B contact, found applications in many fields such as supramolecular chemistry, crystal engineering, medicinal chemistry, and chemical biology. Their large range of applications also led to an increased interest in their study using computational methods aiming not only at understanding the phenomena at a fundamental level, but also to help in the interpretation of results and guide the experimental work. Herein, a succinct overview of the recent theoretical and experimental developments is given starting by discussing the nature of the halogen bond and the latest theoretical insights on this topic. Then, the effects of the surrounding environment on halogen bonds are presented followed by a presentation of the available method benchmarks. Finally, recent experimental applications where the contribution of computational chemistry was fundamental are discussed, thus highlighting the synergy between the lab and modeling techniques.

The Seasonal cycle of the Tropical Lower Stratospheric Water Vapor in Chemistry-Climate Models in Comparison with Observations

NASA Astrophysics Data System (ADS)

Wang, X.; Dessler, A. E.

2017-12-01

The seasonal cycle is one of the key features of the tropical lower stratospheric water vapor, so it is important that the climate models reproduce it. In this analysis, we evaluate how well the Goddard Earth Observing System Chemistry Climate Model (GEOSCCM) and the Whole Atmosphere Community Climate Model (WACCM) reproduce the seasonal cycle of tropical lower stratospheric water vapor. We do this by comparing the models to observations from the Microwave Limb Sounder (MLS) and the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim (ERAi). We also evaluate if the chemistry-climate models (CCMs) reproduce the key transport and dehydration processes that regulate the seasonal cycle using a forward, domain filling, diabatic trajectory model. Finally, we explore the changes of the seasonal cycle during the 21st century in the two CCMs. Our results show general agreement in the seasonal cycles from the MLS, the ERAi, and the CCMs. Despite this agreement, there are some clear disagreements between the models and the observations on the details of transport and dehydration in the TTL. Finally, both the CCMs predict a moister seasonal cycle by the end of the 21st century. But they disagree on the changes of the seasonal amplitude, which is predicted to increase in the GEOSCCM and decrease in the WACCM.

United States Army Biomedical Research and Development Laboratory Annual Progress Report FY90

DTIC Science & Technology

1991-01-01

pesticide . Parallel and follow-on studies will include hydrolysis products of nerve agents , vesicants, and agents of...Division FO Fog oil FORSCOM U.S. Army Forces Command FY Fiscal year 249 GA The nerve agent tabun GB The nerve agent soman GD The nerve agent sarin GLP... Nerve Agents , Industrial Hygiene Sampling, Microbiology, Combustion Products, Liquid Gun Propellant, Organic Chemistry, Inorganic

High School Students' Engagement in Planning Investigations: Findings from a Longitudinal Study in Spain

ERIC Educational Resources Information Center

Crujeiras-Pérez, B.; Jiménez-Aleixandre, M. P.

2017-01-01

This paper examines the process of high school students' planning investigations in the chemistry laboratory across two consecutive academic years in terms of their actions and their progress. The context is a set of five inquiry-based laboratory tasks in which participants (9th and 10th graders, 14-15 and 15-16 years of age) are required to plan…

Laboratory directed research and development. FY 1995 progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vigil, J.; Prono, J.

1996-03-01

This document presents an overview of Laboratory Directed Research and Development Programs at Los Alamos. The nine technical disciplines in which research is described include materials, engineering and base technologies, plasma, fluids, and particle beams, chemistry, mathematics and computational science, atmic and molecular physics, geoscience, space science, and astrophysics, nuclear and particle physics, and biosciences. Brief descriptions are provided in the above programs.

Using Laboratory Activities Enhanced with Concept Cartoons to Support Progression in Students' Understanding of Acid-Base Concepts

ERIC Educational Resources Information Center

Ozmen, Haluk; Demircioglu, Gokhan; Burhan, Yasemin; Naseriazar, Akbar; Demircioglu, Hulya

2012-01-01

The aim of this study is to examine the effectiveness of an intervention based on a series of laboratory activities enhanced with concept cartoons. The purpose of the intervention was to enhance students' understanding of acid-base chemistry for eight grade students' from two classes in a Turkish primary school. A pretest-posttest non-equivalent…

Classical Challenges in the Physical Chemistry of Polymer Networks and the Design of New Materials.

PubMed

Wang, Rui; Sing, Michelle K; Avery, Reginald K; Souza, Bruno S; Kim, Minkyu; Olsen, Bradley D

2016-12-20

Polymer networks are widely used from commodity to biomedical materials. The space-spanning, net-like structure gives polymer networks their advantageous mechanical and dynamic properties, the most essential factor that governs their responses to external electrical, thermal, and chemical stimuli. Despite the ubiquity of applications and a century of active research on these materials, the way that chemistry and processing interact to yield the final structure and the material properties of polymer networks is not fully understood, which leads to a number of classical challenges in the physical chemistry of gels. Fundamentally, it is not yet possible to quantitatively predict the mechanical response of a polymer network based on its chemical design, limiting our ability to understand and characterize the nanostructure of gels and rationally design new materials. In this Account, we summarize our recent theoretical and experimental approaches to study the physical chemistry of polymer networks. First, our understanding of the impact of molecular defects on topology and elasticity of polymer networks is discussed. By systematically incorporating the effects of different orders of loop structure, we develop a kinetic graph theory and real elastic network theory that bridge the chemical design, the network topology, and the mechanical properties of the gel. These theories show good agreement with the recent experimental data without any fitting parameters. Next, associative polymer gel dynamics is discussed, focusing on our evolving understanding of the effect of transient bonds on the mechanical response. Using forced Rayleigh scattering (FRS), we are able to probe diffusivity across a wide range of length and time scales in gels. A superdiffusive region is observed in different associative network systems, which can be captured by a two-state kinetic model. Further, the effects of the architecture and chemistry of polymer chains on gel nanostructure are studied. By incorporating shear-thinning coiled-coil protein motifs into the midblock of a micelle-forming block copolymer, we are able to responsively adjust the gel toughness through controlling the nanostructure. Finally, we review the development of novel application-oriented materials that emerge from our enhanced understanding of gel physical chemistry, including injectable gel hemostats designed to treat internal wounds and engineered nucleoporin-like polypeptide (NLP) hydrogels that act as biologically selective filters. We believe that the fundamental physical chemistry questions articulated in this Account will provide inspiration to fully understand the design of polymer networks, a group of mysterious yet critically important materials.

Organometallic chemistry of heterobimetallic compounds: Final report for the period August 1, 1985-June 30, 1988

DOE Office of Scientific and Technical Information (OSTI.GOV)

Casey, C.P.

1988-03-01

Work is reported on the following: formyl compounds, cyclopentadienyl ring slippage, ..mu..-hydrocarbyl diiron complexes, heterobimetallic compounds linked by heterodifunctional ligands, heterobimetallic dihydrides, reactions of heterobimetallic dihydrides, early-late transition metal bimetallic compounds, and heterobimetallic ..mu..-alkylidene complexes. (DLC)

Bioinformatics Symposium of the Analytical Division of the American Chemical Society Meeting. Final Technical Report from 03/15/2000 to 03/14/2001 [sample pages of agenda, abstracts, index

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kennedy, Robert T.

Sparked by the Human Genome Project, biological and biomedical research has become an information science. Information tools are now being generated for proteins, cell modeling, and genomics. The opportunity for analytical chemistry in this new environment is profound. New analytical techniques that can provide the information on genes, SNPs, proteins, protein modifications, cells, and cell chemistry are required. In this symposium, we brought together both informatics experts and leading analytical chemists to discuss this interface. Over 200 people attended this highly successful symposium.

Molecular similarity and diversity in chemoinformatics: from theory to applications.

PubMed

Maldonado, Ana G; Doucet, J P; Petitjean, Michel; Fan, Bo-Tao

2006-02-01

This review is dedicated to a survey on molecular similarity and diversity. Key findings reported in recent investigations are selectively highlighted and summarized. Even if this overview is mainly centered in chemoinformatics, applications in other areas (pharmaceutical and medical chemistry, combinatorial chemistry, chemical databases management, etc.) are also introduced. The approaches used to define and describe the concepts of molecular similarity and diversity in the context of chemoinformatics are discussed in the first part of this review. We introduce, in the second and third parts, the descriptions and analyses of different methods and techniques. Finally, current applications and problems are enumerated and discussed in the last part.

Functionalization of chitosan by click chemistry

NASA Astrophysics Data System (ADS)

Cheaburu-Yilmaz, Catalina Natalia; Karavana, Sinem Yaprak; Yilmaz, Onur

2017-12-01

Chitosan modification represents a challenge nowadays. The variety of compounds which can be obtained with various architectures and different functionalities made it attractive to be used in fields like pharmacy and material science. Presents study deals with the chemical modification of chitosan by using click chemistry technique. The study adopted the approach of clicking azidated chitosan with a synthesized alkyne terminated polymer i.e. poly N isopropylacrylamide with thermoresponsive properties. Structures were confirmed by the FT-IR and HNMR spectra. Thermal characterization was performed showing different thermal behaviour with the chemical modification. The final synthesized graft copolymer can play important role within pharmaceutical formulations carrying drugs for topical or oral treatments.