949 results on '"Science / Chemistry"'
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2. Chemiebezogene Kompetenzen in der Übergangsphase zwischen dem Sachunterricht der Primarstufe und dem Chemieunterricht der Sekundarstufe I (Volume 336)
- Author
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Behrendt, Alina
- Subjects
Science / Chemistry ,Education - Abstract
Chemiebezogene Kompetenzen werden bereits im Sachunterricht der Grundschule entwickelt und sollen im Chemieunterricht der Sekundarstufe I aufgegriffen und weiterentwickelt werden. Ziel dieser Studie war es, die chemiebezogenen Kompetenzen der Schülerinnen und Schüler in der Übergangsphase zwischen Sachunterricht und Chemieunterricht zu analysieren. In einer Ergänzungsstudie wurden zusätzlich sowohl die Auswirkungen der Schulschließungen aufgrund der SARS-CoV-II Pandemie auf die Kompetenzen der Schülerinnen und Schüler als auch der Einfluss einer veränderten Testadministration untersucht. Insgesamt wurden die Kompetenzen von 2262 Lernenden der Jahrgangsstufen 5 bis 9 zu drei Messzeitpunkten analysiert. Die Ergebnisse zeigen, dass die chemiebezogenen Kompetenzen sowohl zum Ende der Grundschulzeit als auch zu Beginn des Chemieunterrichts über alle Kompetenzbereiche hinweg sehr heterogen ausfallen. Dennoch sind sie zu Beginn des Chemieunterrichts in einigen Kompetenzbereichen höher ausgeprägt als zum Ende der Grundschulzeit. Nach den pandemiebedingten Schulschließungen waren die Kompetenzen ähnlich ausgeprägt wie in den gleichen Jahrgangsstufen vor den Schulschließungen. Eine während der Schulschließungen notwendige Bearbeitung der Testhefte von zu Hause aus führte vor allem bei den jüngeren Schülerinnen und Schülern zu besseren Testergebnissen als die Bearbeitung in der Schule. Um die Entwicklung chemiebezogener Kompetenzen in der Übergangsphase zu optimieren, sollte der Erwerb dieser Kompetenzen bereits im Sachunterricht einheitlicher gestaltet werden.
- Published
- 2022
3. Entwicklung und Evaluation von automatisierten Feedbackschleifen in Online-Aufgaben im Fach Chemie
- Author
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Trauten, Florian
- Subjects
Science / Chemistry ,Education - Abstract
Ein Großteil der Studienabbrüche im Fach Chemie an deutschen Hochschulen (Abbruchquote 52%; Stand 2022) lässt sich auf Lern- und darauf folgende Leistungsprobleme zurückführen. Mit digitalen, feedbackgestützten Lernaufgaben wurde angestrebt, ein binnendifferenzierendes Förderangebot zu erstellen und zu evaluieren, um Wissensdefizite bereits im ersten Semester parallel zur Vorlesung in der Allgemeinen Chemie zu adressieren. Gleichzeitig soll ein Beitrag zur Feedbackforschung geleistet werden, die hinsichtlich des Einflusses von Vorwissen auf die Lernwirksamkeit unterschiedlicher Feedbacktypen bislang keine eindeutige Ergebnislage aufweist.In einem Prä-Post-Vergleichsgruppendesign wurde die Wirkung zweier Feedbacktypen (fehlerspezifisches tutorielles Feedback und korrektives Feedback) untersucht. Die beiden Gruppen (N=122) wurden untereinander und mit einer Kontrollkohorte (N=105) verglichen. Das Lernen mit fehlerspezifischem tutoriellem Feedback ist für alle Studierenden lernwirksam. Es ermöglicht aber Studierenden mit zu Studienbeginn niedrigerem Vorwissen Wissenslücken zu schlieẞen und so gegenüber den Studierenden mit hohem Vorwissen bis zum Semesterende aufzuholen. Rein korrektives Feedback zeigte unter keiner Bedingung einen Vorteil gegenüber elaboriertem Feedback. Die Arbeit liefert damit ein Beispiel für wirksame automatisierte fehlerspezifische Hilfestellungen im webbasierten Übungsbetrieb der Hochschullehre.
- Published
- 2022
4. Entwicklung und Validierung eines Messinstruments zur Erfassung der Schülerkompetenzen im Bereich des wissenschaftlichen Skizzierens im Fach Chemie in der Sekundarstufe I
- Author
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Cavelti, Martina Flurina
- Subjects
Science / Chemistry ,Science ,Education - Abstract
Wissenschaftliches Skizzieren bezeichnet die Fähigkeiten und Fertigkeiten während des Experimentierprozesses objektive Skizzen anzufertigen, die als Basis für Erkenntnisgewinnung dienen. Diese Handlungskompetenz ist in der Schulpraxis relevant für eine nicht-verbale Darstellung von Experimentierprozessen. Es fehlt bisher jedoch ein validiertes Kompetenzmodell. Ziel dieser Arbeit ist es, ein Kompetenzmodell und ein Messinstrument zur Erfassung des wissenschaftlichen Skizzierens zu entwickeln und zu validieren. Es wird eine Skala zum wissenschaftlichen Skizzieren mit 9 Items entwickelt und mit N=374 Schüler:innen (7./9. Jahrgangstufe) und den Variablen Kognition, Strategiewissen beim Experimentieren, Lesefähigkeit und spezifisches Fach- und Methodenwissen validiert. Die Ergebnisse zeigen zunächst, dass sechs Items für ein bezüglich Testgüte valides sowie reliables Messinstrument genügen. Die externe Validierung zeigt, dass der Test zur Kompetenz des wissenschaftlichen Skizzierens erwartungsgemäß ein anderes Konstrukt erhebt als die Kognition, das Strategiewissen zum Experimentieren oder die Lesefähigkeit. Das entwickelte Messinstrument zur Erfassung des wissenschaftlichen Skizzierens ist somit für diagnostische Zwecke einsetzbar. Es kann als ein Messinstrument zur summativen Beurteilung in der Schulpraxis weiterentwickelt werden.
- Published
- 2022
5. Laboratory Manual for Biotechnology and Laboratory Science : The Basics, Revised Edition (Edition 1)
- Author
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Seidman, Lisa A., Kraus, Mary Ellen, Lietzke Brandner, Diana, and Mowery, Jeanette
- Subjects
Science / Chemistry ,Medical / Biochemistry ,Medical / Biotechnology - Abstract
Provides the basic laboratory skills and knowledge to pursue a career in biotechnology. Written by four biotechnology instructors with over 20 years of teaching experience, it incorporates instruction, exercises, and laboratory activities that the authors have been using and perfecting for years. These exercises and activities help students understand the fundamentals of working in a biotechnology laboratory. Building skills through an organized and systematic presentation of materials, procedures, and tasks, the manual explores overarching themes that relate to all biotechnology workplaces including forensic, clinical, quality control, environmental, and other testing laboratories. Features: • Provides clear instructions and step-by-step exercises to make learning the material easier for students. • Emphasizes fundamental laboratory skills that prepare students for the industry. • Builds students’ skills through an organized and systematic presentation of materials, procedures, and tasks. • Updates reflect recent innovations and regulatory requirements to ensure students stay up to date. • Supplies skills suitable for careers in forensic, clinical, quality control, environmental, and other testing laboratories.
- Published
- 2022
6. New approaches for sedimentary basins thermal calibration: towards integration of source rocks Raman spectroscopy and carbonate thermometry
- Author
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Vergara, Natalia Amanda, Corrado, Sveva, and Gasparrini, Marta
- Subjects
Science / Chemistry ,Mathematics / Probability & Statistics ,Science / Earth Sciences / Geology - Abstract
A realistic reconstruction of the time-temperature history of sedimentary basins is critical to understand basin evolution and to predict hydrocarbon (HC) maturation and migration as well as to assess reservoir quality for geothermal and oil and gas exploration purposes. One of the classical approaches for the reconstruction of thermal evolution in sedimentary basins is thermal modelling calibrated against thermal constrains (e.g., vitrinite reflectance, FI microthermometry, % of illite in illite-smectite mixed layers, etc). Thermal calibration of numerical models requires a suitable distribution of paleo-temperature information along the basin and a good understanding on the application limits and reliability of each thermometric tool when applied to different materials (i.e. siliciclastics, carbonates, organic matter, etc.). The present doctoral research project aims to acquire a better understanding on the limitations, advantages and reliability of some conventional (i.e. FIM, vitrinite reflectance and Rock-Eval pyrolysis) and novel (i.e. ∆47 thermometry and Raman spectroscopy) thermometric methods applied to different materials, specifically to: (1) diagenetic carbonates precipitated within the Upper Triassic siliciclastic reservoirs and (2) Dispersed Organic Matter (DOM) from Lower Toarcian source rock intervals.
- Published
- 2022
7. Argumentationslinien in Lehr-Lernkontexten
- Author
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Düwel, Frauke
- Subjects
Literary Criticism / American ,Science / Chemistry ,Education - Abstract
Damit Lehramtsstudierende Lehr-Lernprozesse so gestalten, dass bei Lernenden Erkenntnisprozesse initiiert und unterstützt werden, müssen sie sich vertieft mit den Fachinhalten auseinandersetzen. Die Identifizierung von lernbedeutsamen Zusammenhängen und die Übertragung in Lernschritte sind für Studierende nachweislich schwierig. Daher werden in der vorliegenden Arbeit Verstehensprozesse von Lehramtsstudierenden bei der Erschließung eines komplexen fachlichen Sachverhaltes und dessen fachdidaktische Verwertung untersucht. Dazu wurde eine Fallstudie mit N = 14 Versuchspersonen durchgeführt, für die ein leitfragenstütztes Lehr-Lernkonzept entwickelt wurde, um eine Vertretungsstunde für einen Leistungskurs Chemie zur Auswertung der Analyse eines Farbstoffgemisches zu erarbeiten. Zur Erschließung der inhaltlichen Zusammenhänge wurden englische Lehrbuchtexte (nachweislich weniger lückenhaft in ihren Argumentationslinien als deutsche) eingesetzt. Ausgewertet wurden die Antworten zu den Leitfragen. Die Auswertung erfolgte mit einem auf Propositionen aufbauenden Kategoriensystem. Die Studierenden haben nur teilweise die relevanten Textpassagen eigenständig erkannt. Entscheidend waren die fachlichen Voraussetzungen. Eine Zunahme im fachlichen Verständnis wirkte sich positiv auf die fachdidaktische Verwertung des erworbenen Wissens aus. Folglich sind für die Lehre leitfragenstützte Lehr-Lernkonzepte, auch unter Einbindung englischer Lehrbuchtexte, für eine vertiefte Wissensverarbeitung zu empfehlen.
- Published
- 2022
8. Entwicklung und Evaluation einer Lehrkräftefortbildung zur Planung von selbstgesteuerten Experimenten (Volume 319)
- Author
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Ehlert, Lars
- Subjects
Science / Chemistry ,Science ,Education - Abstract
Das selbstgesteuerte Experimentieren ist laut den nationalen Bildungsstandards sowie den Lehrplänen im Fach Chemie ein wichtiger Bestandteil der naturwissenschaftlichen Schulbildung. Offene Experimentierformen sind jedoch wenig etabliert. Um das selbstgesteuerte Experimentieren in die Unterrichtspraxis zu implementieren, wurde im Rahmen dieses Forschungsprojekts eine eintägige Lehrkräftefortbildung zur Konzeption von selbstgesteuerten Experimenten im Chemieunterricht durchgeführt. Dazu wurde ein literaturbasiertes Strukturierungskonzept entwickelt, mit dem die Lehrkräfte kochbuchartige Schulversuche zu selbstgesteuerten und kompetenzorientierten Experimenten mit beliebigen Öffnungsgraden modifizieren können. Begleitend zur Fortbildung wurde im Prä-Post-Follow-Up-Design das fachdidaktische Wissen der Teilnehmenden hinsichtlich der Planung von selbstgesteuerten Experimenten empirisch überprüft. Zur Erfassung dieses Konstrukts wurde ein neues Messinstrument literaturbasiert entwickelt und die Güte des Messinstruments evaluiert. Die Auswertungen zeigen, dass die Fortbildung hinsichtlich des fachdidaktischen Wissens der Lehrkräfte kurz- sowie langfristig lernförderlich ist und die Fortbildung von den Teilnehmenden positiv bewertet wird. Die Reliabilitätsanalyse sowie die Validierungsstudie zeigen, dass der Test sowohl reliabel als auch valide ist. In Folgestudien könnte die langfristige Verhaltensänderung der Lehrkräfte bezüglich der Implementierung des selbstgesteuerten Experimentierens in den Unterricht untersucht werden.
- Published
- 2021
9. Study of an alternative phase field model for low interfacial energy in elastic solids
- Author
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Böttcher, Anke
- Subjects
Science / Chemistry ,Mathematics ,Science / Physics - Abstract
In 2005, the hybrid model was published by Prof. H.-D. Alber and Prof. P. Zhu as an alternative to the Allen-Cahn model for the description of phase field transformations. With low interfacial energy, it is more efficient, since the resolution of the diffuse interface is numerically broader for the same solution accuracy and allows coarser meshing. The solutions of both models are associated with energy minimisation and in this work the error terms introduced in the earlier publications are discussed and documented using one and two dimensional numerical simulations. In the last part of this book, phase field problems, initially not coupled with material equations, are combined with linear elasticity and, after simple introductory examples, a growing martensitic inclusion is simulated and compared with literature data. In addition to the confirmed numerical advantage, another phenomenon not previously described in the literature is found: with the hybrid model, in contrast to the examples calculated with the Allen-Cahn model, an inclusion driven mainly by curvature energy does not disappear completely. The opposite problem prevents inclusions from growing from very small initial configurations, but this fact can be remedied by a very finely chosen diffuse interface width and by analysing and adjusting the terms that generate the modelling errors. The last example shows that the hybrid model can be used with numerical advantages despite the above mentioned peculiarities.
- Published
- 2021
10. CHEMIE PUR – Unterrichten in der Natur : Entwicklung und Evaluation eines kontextorientierten Unterrichtskonzepts im Bereich Outdoor Education zur Änderung der Einstellung zu „Chemie und Natur“ (Volume 301)
- Author
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Engl, Alexander
- Subjects
Science / Chemistry ,Science ,Education - Abstract
Konsumgüter werden beispielsweise mit Slogans wie "Gut in Bio. Schlecht in Chemie." beworben. Dabei wird intendiert, sich gezielt von "Chemie" abzugrenzen und sich das positive Bild von "Natur" zu Nutze zu machen. Dies prägt die öffentliche Meinung und trägt zu einer antagonistisch-wertenden Sicht von "Chemie" und "Natur" bei. Dass Chemie als Naturwissenschaft der Beschreibung der Natur dient, um deren Stoffe und Stoffumwandlungen zu erklären, ist dem Laien selten bewusst. Chemie findet überall statt, insbesondere in der Natur! Genau an diesem Punkt setzt das Unterrichtskonzept "Chemie Pur - Unterrichten in der Naturglqq an. Ziel ist es, im Freiland, mit direkt vor Ort gewonnenen Naturstoffen, Umweltprozesse experimentell zu erarbeiten. Die projektbegleitende Evaluationsstudie stellte sich der Forschungsfrage, wie sich das Unterrichtskonzept auf das Fach- und Sachinteresse, auf die Naturverbundenheit sowie auf die Einstellung zu Chemie und Natur von Schülerinnen und Schülern der Sekundarstufe II auswirkt. Die Auswertung der Fragebogenergebnisse mit latenten Veränderungsmodellen haben gezeigt, dass die Intervention im Freiland das inhaltsbezogene Sachinteresse steigert und die Einstellung zu Chemie und Natur positiv beeinflusst sowie ein erhöhten Fachwissenszuwachs ermöglicht. Die gewonnenen Erkenntnisse können die Grundlage für die Entwicklung und Evaluation von good-practice-Ansätzen naturwissenschaftlicher Lernsituationen bilden. Das Unterrichtskonzept Chemie Pur leistet zudem einen Beitrag im Bereich Outdoor Education, um den Antagonismus von Chemie und Natur zu verringern.
- Published
- 2020
11. Concomitant Synthesis of Peptides and Oligonucleotides in the Presence of Lipids and Lipid Vesicles
- Author
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Fayolle, Dimitri, Strazewski, Peter, Barthélémy, Philippe, Chaix-Bauvais, Carole, Granjon, Thierry, Defrancq, Eric, Egli, Martin, Richert, Clemens, Ethève-Quelquejeu, Mélanie, and Fiore, Michele
- Subjects
Science / Chemistry ,Science / Chemistry / Organic ,Technology & Engineering / Remote Sensing & Geographic Information Systems - Abstract
Translation of nucleic acids into proteins is a key mechanism to all known forms of life. It relies on a complex biological machinery, and chemists are struggling to mimic translation under conditions that may be representative of the emergence of early forms of life from a prebiotic world. Recently, it was suggested that peptido-RNA, a family of conjugates in which a peptide is bound to an oligonucleotide through a N→5’ phosphoramidate, could provide a simple example of ribonucleotide-promoted peptide synthesis. In addition, cellular life is dependent on the formation and growth of compartments primarily based on self-assembled lipid membranes. In this work, we study the interaction of amphiphilic peptido-RNA, in which a lipophilic peptide is bound to a hydrophilic nucleotide, with membranes in three different ways. We have found that amphiphilic peptido-RNA with random or defined sequences could be formed in the presence of lipid membranes but that the latter exerted no significant influence on the reaction networks at play. In contrast, peptido-RNA with short and medium-length membranophilic peptides could durably interact with lipid membranes, providing a localization mechanism. Finally, it is envisioned that, because phosphoramidates are easily cleaved, this localization could be exploited to allow the permeation of nucleotides and short nucleic acids through membranes without the assistance of enzymes. Our results contribute to shed light on a prebiotic peptide-RNA-lipid world.
- Published
- 2020
12. Caesar's Last Breath : Decoding the Secrets of the Air Around Us
- Author
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Sam Kean and Sam Kean
- Subjects
- Air, Atmosphere, SCIENCE / Chemistry / General, SCIENCE / History, SCIENCE / Chemistry
- Abstract
The Guardian's Best Science Book of 2017: the fascinating science and history of the air we breathe. It's invisible. It's ever-present. Without it, you would die in minutes. And it has an epic story to tell. In Caesar's Last Breath, New York Times bestselling author Sam Kean takes us on a journey through the periodic table, around the globe, and across time to tell the story of the air we breathe, which, it turns out, is also the story of earth and our existence on it. With every breath, you literally inhale the history of the world. On the ides of March, 44 BC, Julius Caesar died of stab wounds on the Senate floor, but the story of his last breath is still unfolding; in fact, you're probably inhaling some of it now. Of the sextillions of molecules entering or leaving your lungs at this moment, some might well bear traces of Cleopatra's perfumes, German mustard gas, particles exhaled by dinosaurs or emitted by atomic bombs, even remnants of stardust from the universe's creation. Tracing the origins and ingredients of our atmosphere, Kean reveals how the alchemy of air reshaped our continents, steered human progress, powered revolutions, and continues to influence everything we do. Along the way, we'll swim with radioactive pigs, witness the most important chemical reactions humans have discovered, and join the crowd at the Moulin Rouge for some of the crudest performance art of all time. Lively, witty, and filled with the astounding science of ordinary life, Caesar's Last Breath illuminates the science stories swirling around us every second.
- Published
- 2017
13. Chemistry 2e
- Author
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Flowers, Paul, Theopold, Klaus, Langley, Richard, and Robinson, William R.
- Subjects
Science / Chemistry - Abstract
Chemistry 2e is designed to meet the scope and sequence requirements of the two-semester general chemistry course. The textbook provides an important opportunity for students to learn the core concepts of chemistry and understand how those concepts apply to their lives and the world around them. The book also includes a number of innovative features, including interactive exercises and real-world applications, designed to enhance student learning. The second edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Substantial improvements have been made in the figures, illustrations, and example exercises that support the text narrative. Changes made in Chemistry 2e are described in the preface to help instructors transition to the second edition. The first edition of Chemistry by OpenStax is available in web view here.
- Published
- 2019
14. Chemistry: Atoms First 2e
- Author
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Flowers, Paul, Neth, Edward J., and Robinson, William R.
- Subjects
Science / Chemistry - Abstract
Chemistry: Atoms First 2e is a peer-reviewed, openly licensed introductory textbook produced through a collaborative publishing partnership between OpenStax and the University of Connecticut and UConn Undergraduate Student Government Association.This text is an atoms-first adaptation of OpenStax Chemistry 2e. The intention of “atoms-first” involves a few basic principles: first, it introduces atomic and molecular structure much earlier than the traditional approach, and it threads these themes through subsequent chapters. This approach may be chosen as a way to delay the introduction of material such as stoichiometry that students traditionally find abstract and difficult, thereby allowing students time to acclimate their study skills to chemistry. Additionally, it gives students a basis for understanding the application of quantitative principles to the chemistry that underlies the entire course. It also aims to center the study of chemistry on the atomic foundation that many will expand upon in a later course covering organic chemistry, easing that transition when the time arrives. The second edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Substantial improvements have been made in the figures, illustrations, and example exercises that support the text narrative. The first edition of Chemistry: Atoms First by OpenStax is available in web view here.
- Published
- 2019
15. Modeling of Moving Sound Sources Based on Array Measurements
- Author
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Meng, Fanyu
- Subjects
Science / Chemistry ,Technology & Engineering / Construction ,Technology & Engineering - Abstract
When auralizing moving sound sources in Virtual Reality (VR) environments, the two main input parameters are the location and radiated signal of the source. An array measurement-based model is developed to characterize moving sound sources regarding the two parameters in this thesis. This model utilizes beamforming, i.e. delay and sum beamforming (DSB) and compressive beamforming (CB) to obtain the locations and signals of moving sound sources. A spiral and a pseudorandom microphone array are designed for DSB and CB, respectively, to yield good localization ability and meet the requirement of CB. The de-Dopplerization technique is incorporated in the time-domain DSB to address moving source problems. Time-domain transfer functions (TDTFs) are calculated in terms of the spatial locations within the steering window of the moving source. TDTFs then form the sensing matrix of CB, thus allowing CB to solve moving source problem. DSB and CB are further extended to localize moving sound sources, and the reconstructed signals from the beamforming outputs are investigated to obtain the source signals. Moreover, localization and signal reconstruction are evaluated through varying parameters in the beamforming procedures, i.e. steering position, steering window length and source speed for a moving periodic signal using DSB, and regularization parameter, signal to noise ratio (SNR), steering window length, source speed, array to source motion trajectory and mismatch for a moving engine signal using CB. The parameter studies show guidelines of parameter selection based on the given situations in this thesis for modeling moving source using beamforming. Both algorithms are able to reconstruct the moving signals in the given scenarios. Although CB outperforms DSB in terms of signal reconstruction under particular conditions, the localization abilities of the two algorithms are quite similar. The practicability of the model has been applied on pass-by measurements of a moving loudspeaker using the designed arrays, and the results can match the conclusions drawn above from simulations. Finally, a framework on how to apply the model for moving source auralization is proposed.
- Published
- 2018
16. Experimentelle und simulative Untersuchung von Dieseloxidationskatalysatoren bei reversibler Edelmetalloxid-Bildung
- Author
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Dubbe, Hendrik Nicolas
- Subjects
Science / Chemistry ,Technology & Engineering / Chemical & Biochemical - Abstract
Neuere Erkenntnisse zum Umsatzverhalten an Dieseloxidationskatalysatoren (DOCs) zeigen, dass das Umsatzverhalten von Schadstoffen vom Oxidationsgrad der verwendeten Edelmetallkatalysatoren abhängen kann. Dabei wird deutlich, dass sich der Oxidationsgrad bei typischen Abgaszusammensetzungen langsam und reversibel mit der Katalysatortemperatur ändert. Das kann bei periodischen Katalysatortemperaturänderungen zu einem ausgeprägten Hystereseverhalten führen. Bisherige Ergebnisse liegen insbesondere zum Verhalten der NO-Oxidation an Platin-Katalysatoren vor. Ziel der vorliegenden Arbeit ist es daher, die Untersuchungen auf seriennahe Pd- und PtPd-Mischkatalysatoren sowie auf andere abgastypische Schadstoffe, wie CO und Kohlenwasserstoffe, zu erweitern und dabei auch den Einfluss der Katalysatoralterung zu erfassen. Es wurde ein globalkinetisches Modell entwickelt und an die experimentellen Befunde angepasst. Dabei zeigte sich, dass es in der Regel möglich ist, das Umsatzverhalten bei reinen Pt- und Pd-Katalysatoren mit diesem örtlich eindimensionalen, makrokinetischen Zweiphasenmodell zutreffend zu beschreiben, wohingegen das Verhalten auf Pt/Pd-Mischkatalysatoren weniger gut simuliert werden kann. Dies ist vermutlich auf die heterogene Struktur der Pt/Pd-legierten Partikel zurückzuführen.
- Published
- 2018
17. Kotla, Sai A.Y. : A Derivation and Application of the Clausius Mossotti Equation using Polar/Non-polar Mixtures
- Subjects
Science / Chemistry ,Education - Abstract
The approaches to theoretical illustration of the solvents and their microscopic properties have not yet been completely described. refractive index, absorbance, dielectric constant, polarizability, molar polarization have been computed experimentally using the Abbe refractometer and BMG Polar star Omega microplate reader.The measured values of refractive index and aforesaid parameters are fitted to the Clausius - Mossotti equation. The overall goal of the project is to calculate the polarizability and absorption coefficient using different concentrations of the toluene in several chose polar solvents.
- Published
- 2017
18. Pfupajena, Tanaka H. : Optimization of Lipid Extraction and Biofuel Production from Algae Grown in Dairy Wastewater
- Subjects
Science / Chemistry ,Education - Abstract
Most fuels used in vehicles and in other equipment on a daily basis are nonrenewable. In addition,the current petroleum based fuel sources are environmentally unfriendly, releasing greenhousegases into the atmosphere. Many alternatives to using natural reservoirs as sources of fuels havebeen explored, among which, the use of algal feedstock as a source of biofuel has receivedenormous attention. The potential of Algal based biofuel has been studied in the past, and hasrecently gained popularity due to the increase in global demand for transportation fuels andreduction of greenhouse gases. Funded by the NSF, at Eastern, we have been cultivating algae onan outdoor pilot unit-- Algal Turf Scrubber® --in dairy manure effluent for wastewatertreatment and sustainable biofuel production. Algae offer an inexhaustible source of energy,nutrients and raw materials. When algae are grown, and harvested, the biomass obtained containslipids, which can be converted into biodiesels via acid or base transesterification.
- Published
- 2017
19. Bai, Bin : High Performance Liquid Chromatographic Analysis of Algal Extracts
- Subjects
Science / Chemistry ,Education - Abstract
The gradual global depletion of fossil reserves has made it imperative for most countries to seek viable alternative sources of energy. Microalgae hold promise as a sustainable source of biofuels based on their rapid growth and reportedly high concentration of lipids. In this project, we cultivated algae in dairy manure effluents on an outdoor pilot unit called Algal Turf Scrubber® (ATS™), with the goal of minimizing the cost of nutrients for algae and simultaneously purifying the wastewater.
- Published
- 2017
20. Innovation Technology : A Dictionary
- Author
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Schramm, Laurier L.
- Subjects
Science / Chemistry - Abstract
Comprise definition of 1500 terms. Innovation from A to Z presents a glossary, including: Terms, older terms whose meanings have changed, acronyms, synonyms, famous names, selected abbreviations, and cross-references. A highly interdisciplinary approach incorporating strategy and entrepreneurship with technology and engineering sciences, economics, marketing, organizational behavior and theory. Ideal for engineers, managers, sales people and economists. Innovation Technology from A to Z Glossary of terms, including acronyms, synonyms, abbreviations, cross-references 1500 terms supplemented by figures and tables that clearly demonstrate the state-of-the-art in Innovation Technology
- Published
- 2017
21. Self-Assembled Molecules – New Kind of Protein Ligands : Supramolecular Ligands
- Author
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Konieczny, Leszek and Roterman, Irena
- Subjects
Science / Chemistry - Abstract
immunotargeting techniques; ligands; intramolecular immunological signals; congo red amyloids
- Published
- 2017
22. Bandi, Saichandra : Relating Nutrient Supply and Removal to the Algal Productivity in an Outdoor Pilot System
- Subjects
Science / Chemistry ,Education - Abstract
Cultivating algae with nitrogen (N) and phosphorous (P) in dairy manure effluent on the Algal Turf Scrubber (ATS) system at ENMU presents an alternative to the current practice of anaerobic digestion. An alternative to land spreading of manure effluent is mass-cultivation of algae with the N and P in the wastewater. The ATS technique lowers the nutrient concentration and increases the dissolved oxygen in the water at a high rate. Moreover, the nutrients that have been removed from the water are stored in the biomass of algae and can be collected to produce biofuels. Our overall project goal is to correlate algal biomass productivity with nutrient levels.
- Published
- 2016
23. Chemistry : Atoms First
- Author
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Robinson, William R., Neth, Edward J., Flowers, Paul, Theopold, Klaus, and Langley, Richard
- Subjects
Science / Chemistry - Abstract
Chemistry: Atoms First is a peer-reviewed, openly licensed introductory textbook produced through a collaborative publishing partnership between OpenStax and the University of Connecticut and UConn Undergraduate Student Government Association. This title is an adaptation of the OpenStax Chemistry text and covers scope and sequence requirements of the two-semester general chemistry course. Reordered to fit an atoms first approach, this title introduces atomic and molecular structure much earlier than the traditional approach, delaying the introduction of more abstract material so students have time to acclimate to the study of chemistry. Chemistry: Atoms First also provides a basis for understanding the application of quantitative principles to the chemistry that underlies the entire course.
- Published
- 2016
24. Traore, Mohamed C. : Optimization of SH3 Domain Protein Expression and Purification Using a Custom Excel-based DOE Program
- Subjects
Science / Chemistry ,Education - Abstract
Protein production is significant for potential therapeutic protein drugs, and is necessary for studying protein-protein interactions, which play a major role in understanding many biological pathways and mechanisms within cells. Thus, the optimization of protein production will be beneficial for therapeutic opportunities of many diseases.
- Published
- 2014
25. Hydroxyapatite Coatings for Biomedical Applications (Edition 1)
- Author
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Zhang, Sam
- Subjects
Science / Chemistry ,Technology & Engineering / Materials Science ,Medical / Biotechnology - Abstract
Hydroxyapatite coatings are of great importance in the biological and biomedical coatings fields, especially in the current era of nanotechnology and bioapplications. With a bonelike structure that promotes osseointegration, hydroxyapatite coating can be applied to otherwise bioinactive implants to make their surface bioactive, thus achieving faster healing and recovery. In addition to applications in orthopedic and dental implants, this coating can also be used in drug delivery. Hydroxyapatite Coatings for Biomedical Applications explores developments in the processing and property characterization and applications of hydroxyapatite to provide timely information for active researchers and newcomers alike.In eight carefully reviewed chapters, hydroxyapatite experts from the United States, Japan, Singapore, and China present the latest on topics ranging from deposition processes to biomedical applications in implants and drug delivery. This book discusses:Magnetron sputtering and electrochemical depositionThe modification of hydroxyapatite properties by sol–gel deposition to incorporate other elements found in natural bones, such as zinc, magnesium, and fluorineThe use of pure hydroxyapatite in drug delivery applicationsThe growth or self-assembly of hydroxyapatite on shape memory alloyHydroxyapatite composite coatings—with carbon nanotubes, titanium dioxide (TiO2), and others—on the titanium alloyOffering valuable insights and a wealth of data, including numerous tables and figures, this is a rich source of information for research on hydroxyapatite coatings. Each chapter also covers material that provides an accessible stepping stone for those who are new to the field.
- Published
- 2013
26. Ferrocenes as One-Electron Donors in Unimolecular Rectifiers
- Author
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Metzger, Robert Melville
- Subjects
Science / Chemistry - Abstract
Ferrocene is a good electron donor, and as such has been used to test asymmetric conduction (rectification) in molecules that contain ferrocene. Of the five ferrocene-containing molecules that rectify (structures 11, 15, 19, 20, and 22), the last (22) exhibits a record rectification ratio, which should be a dramatic incentive for searching for more high-efficiency rectifiers.
- Published
- 2022
27. Preparation and Applications of Nanocomposite Membranes for Water/Wastewater Treatment
- Author
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Ince, Muharrem and Kaplan Ince, Olcay
- Subjects
Science / Chemistry - Abstract
Because of scarcity of clean water all over the globe, it is leads to serious challenges to the survival of all living species. Advanced treatment of water/wastewater techniques such as filtration separation and ion exchange separation are necessary for degradable or non-biodegradable detrimental and hazardous wastes removal from water. Membrane technology is of critical importance to solve this vital problem. In membrane technology, nanocomposite membranes (NCMs) are the most preferred in terms of their convenience. These membranes and their constituent materials are eco-friendly, low-cost, and energy-efficient materials. Also they have operational flexibility and feasibility. The current study presents an overview of the progress in NCMs to treat water/wastewater. To prepare NCMs, various used methods are discussed. Also, to improve the mechanical, antibacterial, and adsorption, properties of NCMs have been investigated. The objective of this work was to summarize the removal of toxic wastes from water/wastewater using various NCMs and to emphasize the shortfalls, and future prospective of NCMs technology are highlighted.
- Published
- 2022
28. Printing of Textiles Using Natural Dyes : A Global Sustainable Approach
- Author
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Kavyashree, M.
- Subjects
Science / Chemistry - Abstract
Globalization has completely changed the fashion industry and its approach toward sustainability. Fast changing trends are majorly focused on synthetic dyes and fabrics. And these products have failed building the bridge between sustainability and environment-friendly designs. Therefore, this chapter is aimed at the approach toward design development and development of sustainable eco-friendly approach for screen printing by using natural dyes on fabrics like silk and cotton. The chapter is based on sustainable design approach which gives much provision for using natural dyes for everyday change in fashion. The chapter also focuses on color fastness properties of the used dyes. These results were evaluated by carrying out color fastness tests for light, wash, rubbing, and perspiration using standard testing methods. Design methodology used in the study also has the potential for skill development programs for entrepreneurs and also contributes to rural development programs by creating sustainable growth.
- Published
- 2022
29. Application of Titanium Dioxide in the Synthesis of Mesoporous Activated Carbon Derived from Agricultural Waste
- Author
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Singh, Kaman, Kumar, Ashok, and Ahamad Bhat, Rayees
- Subjects
Science / Chemistry - Abstract
Adsorption is an important technique that significances the characteristics of porous solid materials and fine powders. The importance of porous solid materials and fine powders has been recognized when porous coal used for various applications such as catalysis, separation, isolation, sensors, chromatography, etc. Herein, the synthesis of mesoporous activated carbon derived from agricultural waste using TiO2. The TiO2-modified carbon was characterized employing scanning electron microscope (SEM), attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, powder X-ray diffraction (pXRD), Brunauer–Emmett–Teller (BET) surface area analyzer and X-ray photoelectron spectroscopy (XPS). The obtained results suggested that the TiO2-modified carbon could be a potential material for various application like dye removal, metal removal and allied areas. This book chapter describes the commonly used classifications of porous bulk materials and also reported here the characterization of porous solid materials and fine powders with special reference to the evaluation of the surface area, pore size distribution and thermodynamic parameters of the different mesoporous material, at various scales of resolution using relevant techniques. These materials comprise several levels of structures that of the mesopores, micropores as well as macropores. The apparent topography analysis of these materials, of various pore diameters, synthesized in our laboratory has been determined at various scales with the help of various characterization techniques.
- Published
- 2022
30. Green Chemistry Applied to Transition Metal Chalcogenides through Synthesis, Design of Experiments, Life Cycle Assessment, and Machine Learning
- Author
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Pinto, Alexandre, Cho, Dylan, Oliynyk, Anton, and Silverman, Julian
- Subjects
Science / Chemistry - Abstract
Transition metal chalcogenides (TMC) is a broad class of materials comprising binary, ternary, quaternary, and multinary oxides, sulfides, selenides, and tellurides. These materials have application in different areas such as solar cells, photocatalysis, sensors, photoinduced therapy, and fluorescent labeling. Due to the technological importance of this class of material, it is necessary to find synthetic methods to produce them through procedures aligned with the Green Chemistry. In this sense, this chapter presents opportunities to make the solution chemistry synthesis of TMC greener. In addition to synthesis, the chapter presents different techniques of experimental planning and analysis, such as design of experiments, life cycle assessment, and machine learning. Then, it explains how Green Chemistry can benefit from each one of these techniques, and how they are related to the Green Chemistry Principles. Focus is placed on binary chalcogenides (sulfides, selenides, and tellurides), and the quaternary sulfide Cu2ZnSnS4 (CZTS), due to its application in many fields like solar energy, photocatalysis, and water splitting. The Green Chemistry synthesis, characterization, and application of these materials may represent sustainable and effective ways to save energy and resources without compromising the quality of the produced material.
- Published
- 2022
31. One-Pot-Condensation Reaction of Heterocyclic Amine, 1,3-Diketone and Aldehydes Using <em>In Situ</em> Generated Superoxide Ion : A Rapid Synthesis of Structurally Diverse Drug-Like Complex Heterocycles
- Author
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Singh, Sundaram and Kumari, Savita
- Subjects
Science / Chemistry - Abstract
A novel, convenient one-pot multicomponent synthesis of tetraheterocyclicbenzimidazolo/benzothiazolo quinazolin-1-one derivatives has been reported in the presence of tetraethylammonium superoxide under non-aqueous condition. The superoxide induced three-component reaction of various aromatic aldehydes, 2-aminobenzimadazole/2-aminobenzothiazole and dimedone/1,3- cyclohexanedione produced tetraheterocyclicbenzimidazolo/benzothiazolo quinazolin-1-one derivatives at room temperature under the mild reaction conditions. The tetraethylammonium superoxide has been generated by phase transfer reaction of potassium superoxide and tetraethylammonium bromide in dry DMF at room temperature. The present study extended the applicability of tetraethylammonium bromide as a phase transfer catalyst for the efficient use of superoxide ion in multi-component synthesis of structurally diverse drug-like complex heterocycles (quinazolines).
- Published
- 2022
32. Calcium Uptake on Kaolinite and Gibbsite : Effects of Sulfate, pH, and Salt Concentration with Additional Insight from Second Harmonic Generation on Temperature Dependencies with Sapphire-Basal Planes and the Potential Relevance to Ice Nucleation
- Author
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Abdelmonem, Ahmed, Alves, Marcelo, Lützenkirchen, Johannes, and Wang, Yujun
- Subjects
Science / Chemistry - Abstract
Although previous studies have shown that sulfate can either increase cation leaching or enhance cation adsorption in soil, little is known about the factors behind these phenomena. To learn more about them, calcium adsorption experiments were carried out with kaolinite and gibbsite at initial pH values 4 and 6 and in the presence of 1 or 20 mmolc L−1 of either nitrate or sulfate. The results indicated that limited sulfate-calcium coadsorption occurred on gibbsite when it was in contact with the dilute solution of CaSO4.2H2O at pH ~ 7. Regarding mineral and pH values, calcium adsorption from the concentrated solutions decreased with sulfate possibly because of the presence of ~31% of the CaSO40 ion pair in the concentrated CaSO4.2H2O solutions and the low free calcium activity therein. Calcium adsorption on kaolinite and gibbsite from all concentrated solutions was reduced when the initial pH changed from 4 to 6 suggesting a negative salt effect on that process. In addition to indicating negligible participation of gibbsite in calcium adsorption, our findings also suggest that higher amounts of gypsum applied to lime-amended oxisols reduce the effectiveness of the main oxisol clay-sized mineral capable of adsorbing cations, i.e., kaolinite, to impair calcium leaching. The uptake data were complemented with some zeta-potential measurements, which supported the lack of substantial uptake of calcium even in the presence of sulfate. Some modeling calculations using the only available model covering sulfate and calcium on gibbsite have been done to rationalize the experimental data, but the model is only able to involve pure electrostatic attraction of calcium, which is not sufficient to produce substantial uptake. Finally, the aluminol basal plane that is present on both gibbsite and kaolinite has been additionally studied using second harmonic generation (SHG) down to 4°C, because the ion-pair formation decreases with decreasing temperature. The second harmonic results confirm the patterns observed in the electrokinetic measurements with kaolinite being quite comparable to the sapphire basal plane. Also and quite clearly, the presence of CaSO4 solutions caused temperature dependence different from pure CaCl2 and Na2SO4 solutions. The latter were essentially behaving like pure water. The difference between the calcium chloride and sulfate systems can be explained by sulfate interaction and might be linked to the temperature dependence of the formation of the CaSO4 ion pair. The temperature dependency study could be an important starting point for looking at ice nucleation in the presence of the three different solutions and more strongly link aqueous chemistry to ice nucleation processes.
- Published
- 2022
33. Application of Two-Dimensional Gel Electrophoresis in Combination with Mass Spectrometry in the Study of Hormone Proteoforms
- Author
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Zhan, Xianquan and Zhou, Tian
- Subjects
Science / Chemistry - Abstract
Hormone is a category of important endocrine regulatory proteins in human endocrine systems. Clarification of hormone proteoforms directly leads to understanding of its biological roles. Two-dimensional gel electrophoresis (2DGE) in combination with mass spectrometry (MS) plays important roles in identification of hormone proteoforms such as human growth hormone (hGH) proteoforms and human prolactin (hPRL) proteoforms. This book chapter will review the hormone proteoforms focusing on hGH and hPRL, the methodology of hormone proteoform study, and future perspective of human hormone proteoform study to find biomarkers for in-depth understanding of molecular mechanisms, and individualized and precise diagnosis, therapy, and prognostic assessment of hormone-related diseases.
- Published
- 2022
34. Photophysics of BODIPY Dyes : Recent Advances
- Author
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Cetindere, Seda
- Subjects
Science / Chemistry - Abstract
BODIPY dyes are unique fluorophores that can be used in numerous application areas because of their interesting photophysical properties such as high molar absorptivity, tunable absorption and emission energies, and high fluorescence quantum yields. They show impressive photophysical property changes upon substitution of functional groups on the main core structure. Exchange of the meso-carbon on dipyrrin core with nitrogen produces an analog class of BODIPY called aza-BODIPY. Up to now, various kinds of BODIPY and aza-BODIPY derivatives have been developed and applied in science and industry. In this chapter, recent studies on photophysical properties of BODIPY derivatives are summarized.
- Published
- 2022
35. Bioethanol Production from Lignocellulosic Biomass
- Author
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Nguyen, Dinh Quan, Le, Thi Kim Phung, Tran, Thi Tuong An, and Mai, Thanh Phong
- Subjects
Science / Chemistry - Abstract
An overview of the basic technology to produce bioethanol from lignocellulosic biomass is presented in this context. The conventional process includes two main steps. First, lignocellulose must be pretreated in order to remove lignin and enhance the penetration of hydrolysis agents without chemically destruction of cellulose and hemicellulose. Second, the pretreated material is converted to bioethanol by hydrolysis and fermentation. Some typical published studies and popular processing methods in attempts to improve the biomass conversion to bioethanol and increase the cost-effectiveness are also introduced briefly. Herein, the refinery of the resulted raw bioethanol mixture to obtain higher concentrated solution is not regarded.
- Published
- 2022
36. Bent-Core Liquid Crystals : Structures and Mesomorphic Properties
- Author
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Carlescu, Irina, Hurduc, Nicolae, Lisa, Gabriela, Ciobanu, Catalina Ionica, Bulai (Cioanca), Elena-Raluca, and Scutaru, Dan
- Subjects
Science / Chemistry - Abstract
Bent-core (BC) molecules became an attractive liquid crystal class due to their potential use in smart displays and photonic devices. In contrast to calamitic mesogens, bent-shaped mesogens are self-organized superstructures with remarkable properties, given the presence of polar order in mesophases, although the molecules themselves are not chiral. A particular interest represents the biaxial nematic liquid crystal materials that are used in display technology and allow a faster switching response, compared to calamitic liquid crystals, with considerably reduced costs. This chapter briefly reviews the bent-core liquid crystals with three different core units in the structure: (1) 2,5-disubstituted oxadiazole, (2) 1,3-disubstituted benzene, and (3) 2,7-disubstituted naphthalene. To the central bent units (BUs) containing reactive functional groups of phenolic or aminic type, various mesogenic groups are symmetrically or asymmetrically connected, via esterification or condensation reactions. The obtained compounds showed biaxial nematic and/or smectic mesophases with high transition temperatures in the case of oxadiazole derivatives or cholesteric and banana-type mesophases with lower transition temperatures in the case of benzene and naphthalene derivatives.
- Published
- 2022
37. Dyeing Chemicals
- Author
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Mamun Kabir, Shekh Md. and Koh, Joonseok
- Subjects
Science / Chemistry - Abstract
Dyeing auxiliaries play an important role in the determination of the final dyeing quality. The formation of additional complexes with dyes and auxiliary agents enhances the exhaustion of dyes on textile substrates. For aqueous-based dyeing, dye auxiliaries such as chelating agents, dispersing agents, leveling agents, electrolyte, pH control agents, and surfactants form complexes with the dye on natural and synthetic fibers. A growing awareness of the impact of industrial pollution on the environment became crucial for the dyeing industry in the closing decades of the twentieth century. These chapters discuss the characteristics of dyeing chemicals and how auxiliary substances can assist in achieving outstanding dyeing performance.
- Published
- 2022
38. Thermally Activated Delayed Fluorescence (TADF) Compounds as Photocatalyst in Organic Synthesis : A Metal-Free Greener Approach
- Author
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Patel, Bhisma K.
- Subjects
Science / Chemistry - Abstract
Thermally activated delayed fluorescent (TADF) molecules undergo efficient intersystem crossing (ISC) and reverse intersystem crossing (RISC) processes, making them as third-generation emitters in organic light-emitting diodes (OLEDs), photodynamic therapy (PDT) and time-resolved luminescence imaging. Apart from these applications, recently, TADF molecules have been used extensively as photocatalysts in light-mediated synthesis. In general, highly expensive complexes of Rh, Ir, Ru and organic dyes (Eosin Y, Rose Bengal, 9-mesityl-10-methylacridinium perchlorate [Acr-Mes]+ClO4‚àí) are commonly used in the photocatalysis process. Organic-TADF based molecules help to avoid these costly metal catalysts and frequently used organic dyes, making the reaction economical and greener. This chapter will briefly summarize the photocatalytic properties of organic-TADF compounds in organic synthesis.
- Published
- 2022
39. Waste to Energy and Syngas
- Author
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Posada, Enrique and Saenz, Gilmar
- Subjects
Science / Chemistry - Abstract
Getting energy from waste is one of the best alternatives for sustainable handling of waste. Mass burning is generally the preferred option. Usually, this applies to large facilities where more than 500 tons of waste per day are treated. Syngas production from waste has also been tried with mixed success. This chapter reviews the situation in this field and proposes an alternative based on co-combustion with coal as a possible route, applied preferably to treat municipal solid waste (MSW) and biosolids from small- or medium-sized municipalities, producing less than 200 tons of waste per day, with the aim of generating electric energy. For this, a theoretical model is proposed and applied to a specific case.
- Published
- 2022
40. Analytical, Bioanalytical, Stability-Indicating Methods : Key Part of Regulatory Submissions
- Author
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Deshpande, Mahesh Mukund
- Subjects
Science / Chemistry - Abstract
According to the International Conference for Harmonization (ICH), the validation and verification data must be included in the Electronic Common Technical Document. The validated analytical procedure gets automatically Food and drug approved (FDA) if it is part of New drug application (NDA), Abbreviated new drug application (ANDA) or Biologic license application (BLA). The analytical, bioanalytical and stability-indicating methods are essential part of all above said regulatory submissions. There are certain ways to generate these analytical methods like U.S. pharmacopeia/National Formulary which are Food and drug approved. The validated analytical method can also be submitted by any researcher or agency which can gets the food and drug approval. It is necessary that the methods which are Food and drug approved can only be applied to the various drugs and drugs products. In the current chapter, the meaning and requirements of analytical methods, procedures, acceptance criteria and evaluation of stability indicating methods, need, recommendations for bioanalytical methods are discussed in detail. The analytical techniques like HPTLC, HPLC, Spectrophotometry and Hyphenated techniques are also discussed as these are playing important role in validation of these methods.
- Published
- 2022
41. Cyclic Voltammetry and Its Applications
- Author
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Chooto, Pipat
- Subjects
Science / Chemistry - Abstract
Cyclic voltammetry is a versatile method for scientific investigation and innovation due to the fact that most processes involve electron transfer, which makes them be able to be monitored by this technique. Its uses cover characterization, synthesis, mechanisms, and analysis. In all applications, the technique can work well with a large variety of compounds including organic, inorganic, polymer, films, and semiconductors, among others. Furthermore, the method operates satisfactorily whether in a direct or an indirect approach. It can be considered to be an essential part at the very beginning that leads further to the grand project. As an analytical tool, it plays an important role in not only chemistry but also other involving areas. This review sheds the light on the way the technique proves to become one of the important instruments in research, development, and application labs.
- Published
- 2022
42. Quantitative and Qualitative LC-High-Resolution MS : The Technological and Biological Reasons for a Shift of Paradigm
- Author
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Rochat, Bertrand
- Subjects
Science / Chemistry - Abstract
Today, high-resolution mass spectrometry (HRMS: Q-TOF-MS, Orbitrap-MS) shows sensitive and reliable quantifications of a large variety of compounds while acquiring in high-resolution full-scan mode. Interestingly, HRMS shows equal quantitative performance than triple-quadrupole-MS (QQQ-MS), which is the MS technology traditionally used for quantification. But, in contrast to QQQ-MS that performs “narrow-minded” ion transitions (targeted prior determination), analysis using HRMS can record HR-full scan that detects virtually all ions (e.g., from m/z = 80 to 1000) and gives a global picture of what is in the biological sample (diagnostic screening). This is more and more seen as a key advantage because on top of targeted and quantitative analyses, many other routine or research determinations can be performed such as qualitative (identification), simultaneous quantitative/qualitative (quan/qual), and omics (untargeted) assays. The high versatility and performance of most actual HRMS instruments placed them as new gold standards in LC-MS analysis. Indeed, only HRMS can answer new analytical requests from systems biology and personalized medicine requesting more holistic approaches with untargeted analyses (e.g., proteomics and metabolomics). In the light of the new HRMS-based paradigm, concrete examples revealing quantitative, qualitative, simultaneous quan/qual, and omics capabilities of HRMS in the context of routine and research analyses will be given.
- Published
- 2022
43. X-Ray Crystal Structure Analysis of Selected Benzimidazole Derivatives
- Author
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Thiruvalluvar, Aravazhi Amalan, Vasuki, Gopalsamy, Rosepriya, Sivaraman, and Jayaraman, Jayabharathi
- Subjects
Science / Chemistry - Abstract
This chapter describes the X-ray crystal structure analysis of selected benzimidazole derivatives, viz. BIP: 2-(1H-benzimidazol-2-yl)phenol, MBMPBI: 1-(4-methylbenzyl)-2-(4-methylphenyl)-1H-benzimidazole, DPBI: 1,2-diphenyl-1H-benzimidazole, PBIP: 2-(1-phenyl-1H-benzimidazol-2-yl)phenol, FPPBI: 2-(4-fluorophenyl)-1-phenyl-1H-benzimidazole and NPBIBHS: 2-(naphthalen-1-yl)-1-phenyl-1H-benzimidazole benzene hemisolvate. The BIP molecule is planar, and in the crystal, it is arranged in parallel planes, stabilised by π-π interactions and the hydrogen bonds. In MBMPBI, benzimidazole cores of the two independent (A and B) molecules are planar. Two C▬H…N hydrogen bonds link B molecules only, forming centrosymmetric dimers with R22(8) ring motifs. In the DPBI molecule, the benzimidazole core is planar: one hydrogen-bond interaction (C▬H…N) and C▬H…π (three) interaction leading to the three-dimensional arrangement. In the PBIP molecule, the benzimidazole is nearly planar. The hydrogen bonds and a π-π stacking interaction are present in the crystal. In the FPPBI molecule, the benzimidazole unit is almost planar. The C▬H…F hydrogen bonds and weak C▬H…π interactions lead to a three-dimensional architecture in the crystal. In NPBIBHS, the naphthalene fragment lies out of the plane about the benzimidazole core unit. The C▬H…N hydrogen bonds and C▬H…π interactions lead to a three-dimensional architecture in the crystal.
- Published
- 2022
44. Large-Area Synthesis and Growth Mechanism of Graphene by Chemical Vapor Deposition
- Author
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Dai, GuiPing, Wang, Chen, and Vinodgopal, Kizhanipuram
- Subjects
Science / Chemistry - Abstract
There has been continuous progress in the development of different synthesis methods to readily produce graphene at a lower cost. Compared with the other methods, chemical vapor deposition (CVD) is an effective and powerful method of producing graphene and has attracted increased attention during the last decade. In this way, we can obtain good uniformity with a multitude of domains, excellent quality, and large scale of the produced graphene. Meanwhile, it is also helping for large-area synthesis of single-crystal graphene. In the CVD method, precursors are typically absorbed on the surface followed by pyrolytic decomposition, which leads to the generation of absorption sites on the surface and promotes the growth of continuous thin films.
- Published
- 2022
45. Stability of Vanadium Chalcone Complexes
- Author
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Borge, Vikas Vilas and Patil, Raju M.
- Subjects
Science / Chemistry - Abstract
The vanadyl(IV) complexes of substituted chalcones were prepared by refluxing vanadyl sulphate with different substituted chalcones in ethanoic medium. The chalcones were prepared with different aromatic aldehydes like benzaldehyde, hydroxy benzaldehyde, nitro benzaldehyde and chloro benzaldehyde. The synthesized Vanadium complexes were characterized by different spectral techniques. The IR spectral studies revealed that the chalcone derivatives are bidentate ligand. Magnetic studies, electron spin resonance and UV studies suggest that the complexes are in square pyramidal geometry. Conductance measurements suggest that all complexes are non-electrolyte in DMF. The thermal study explained the stability of complex and its decomposition. The synthesized ligand and metal complexes were screened for their antibacterial activity against E. coli and Staphylococcus aureus bacterial strains and for antifungal activity against P. notatum.
- Published
- 2022
46. Recent Progress in the Electrochemical Exfoliation of Colloidal Graphene : A Review
- Author
-
Singh, Randhir
- Subjects
Science / Chemistry - Abstract
Graphene is a wonder nanomaterial which is used in a wide variety of electronics applications because of its excellent electrical, optical, chemical and mechanical properties. For the efficient use of graphene in the preparation of modern electronics devices it is imperative to first prepare a colloidal solution of graphene. Although various techniques are being used for the synthesis of colloidal form of graphene, the synthesis of colloidal graphene via electrochemical exfoliation is time saving and easy, facile method which can be easily performed in the laboratory without any expensive and sophisticated equipment as required in other techniques. Through electrochemical exfoliation of colloidal graphene, high quality graphene can be obtained within short time. Further, after the electrochemical exfoliation of colloidal graphene, the colloidal solution is stable in the organic solvent for few weeks. The conducting electrodes prepared by this colloidal solution of graphene have wide application in the areas of flexible energy storage devices and sensors fabrication.
- Published
- 2022
47. Extraction and Fractionation of Polysaccharides from a Selected Mushroom Species, Ganoderma lucidum : A Critical Review
- Author
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Choong, Yew Keong, Mohamad, Shaiful Azuar, Chen, Xiang-Dong, and Ellan, Kavithambigai
- Subjects
Science / Chemistry - Abstract
Fractionation plays a big role in most of the sample processing especially in mushroom polysaccharides extraction. This intermediate step will determine further purification process which will lead to the type of polysaccharides that will be obtained. Four types of Ganoderma lucidum cultured medium used in the research papers were randomly chosen. They are spores, mycelia, fruiting body and fermentation broth. For water soluble polysaccharides, hot water extraction is typically applied. The following ethanol precipitation could be appropriate used to sediment the component with OH-group including polysaccharide. The next step of fractionation consist of anion exchange chromatography or gel filtration enhance the purity of polysaccharides. Using these extraction and fractionation techniques, high quality polysaccharides could be successfully obtained from the mushroom that are useful for further studies. This review examined the various extraction and fractionation techniques used in the study of polysaccharides from G. lucidum.
- Published
- 2022
48. Colloidal Stability of Cellulose Suspensions
- Author
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Stygar Lopes, Marina
- Subjects
Science / Chemistry - Abstract
Cellulose is the most abundant natural compound in nature and the main component of the cell wall of plants. It is a linear polymer with a high degree of polymerization, responsible for most of the properties of wood. Colloidal phenomena are often used in various industrial production processes. Suspended cellulose, used worldwide in the paper and cellulose industries, with regard to stability, has a high tendency to aggregate and form clots. The different interactions between the dispersed phase and the dispersion phase are one of the critical points in the study of the behavior and stability of colloids. Cellulose is no different, as several studies seek to improve the colloidal stability of cellulose in aqueous media by observing the specific characteristics of the colloid, such as its geometry, mass and area/volume ratio, and the possible interactions between particles that make up the cellulose dispersion in order to understand and control colloidal stability. Therefore, the objective of this chapter is to define the main characteristics of colloids, to classify them, to present the main methods of preparation, to address important aspects about colloid stability and the colloidal stability of cellulose.
- Published
- 2022
49. Potential of Biocatalysis in Pharmaceuticals
- Author
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Nigam, Vinod, Prabha, Riddhi, and Soy, Snehi
- Subjects
Science / Chemistry - Abstract
Biocatalysis has been continuously evolving as an essential tool which is playing a significant role in the industrial synthesis of chemicals, active pharmaceuticals, pharmaceutical intermediates, etc. where the high-yielding chemo-, regio-, and enantioselective reactions are needed. Despite its vital importance, industrial biocatalysis is facing certain limitations such as operational stability, economic viability, efficient recovery, and reusability. The limitations mentioned can be overcome by the isolation of specific enzyme producers from extreme environment by protein engineering, bioinformatics, and recombinant DNA technologies. Recently, chemoenzymatic pathway and biological cascade reactions have also been developed and designed to perform the synthesis of pharmaceuticals. In this chapter, we compile the broad applications of biocatalysts in the synthesis of pharmaceuticals.
- Published
- 2022
50. Pyrolysis-GC/MS, A Powerful Analytical Tool for Additives and Polymers Characterization
- Author
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Huertas de la Torre, Sonia
- Subjects
Science / Chemistry - Abstract
Analytical Pyrolysis technique hyphenated to GC/MS is used to obtain structural information of macromolecules. The composition and relative abundance of the pyrolysis products are characteristic for a given polymer and their determination allows the identification of materials that cannot be determined otherwise. In the present work different examples are presented in which different pyrolysis techniques are used, such as pulsed, fractional and sequential pyrolysis, working with polymer solutions, cold injection in split or narrow band mode or thermochemolysis. Specially useful is serial pyrolysis which is performed in two or more steps. Initially, volatile compounds are thermally extracted from the sample at a relatively low temperature (thermal desorption), and then the same sample is pyrolyzed at a higher temperature.
- Published
- 2022
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