Chemical Education

Distillation: integration of a historical perspective

by Marco Lagi

Intensive Propagation of the Lactic Acid Bacterium Lactococcus Lactis

by Myrto-Panagiota Zacharof

A Thesis Submitted for the Requirements of the Degree of Master in Pholosophy, (MPhil) , University of Wales, Swansea, 2006

Comparing Two Tests of Formal Reasoning in a College Chemistry Context

by Xiaoying Xu

co-anthor

The Test of Logical Thinking (TOLT) and the Group Assessment of Logical Thinking (GALT) are two of the instruments... more The Test of Logical Thinking (TOLT) and the Group Assessment of Logical Thinking (GALT) are two of the instruments most widely used by science educators and researchers to measure students’ formal reasoning abilities. Based on Piaget’s cognitive development theory, formal thinking ability has been shown to be essential for student achievement in science and chemistry courses. The major difference between TOLT and GALT is two concrete items relating to conservation of mass and volume, which GALT contains over and above TOLT. The first intent of this study was to determine whether the two concrete items represent an advantage for the general chemistry population in terms of test reliability, discriminatory power, and item bias. Accordingly, TOLT and “TOLT + 2” (TOLT with the extra two concrete items) were each administered to a sample of over 900 students enrolled in first-semester general chemistry. The two concrete items were not observed to provide any advantage, and DIF analysis suggests that TOLT is tenably a less biased test. The second part of the study entailed a direct comparison between TOLT and GALT as intact instruments. GALT was found to have no advantage over TOLT in terms of reliability, discriminatory power, or potential item bias for either general chemistry or preparatory chemistry students.

Diagnosing changes in attitude in first-year college chemistry students with a shortened version of Bauer’s semantic differentia

by Xiaoying Xu

co-author

Refinement of a Chemistry Attitude Measure for College Students

by Xiaoying Xu

This work presents the evaluation and refinement of a chemistry attitude measure, Attitude toward the Subject of... more This work presents the evaluation and refinement of a chemistry attitude measure, Attitude toward the Subject of Chemistry Inventory (ASCI), for college students. The original 20-item and revised eight-item versions of ASCI (V1, V2, and V3) were administered to different samples. The evaluation for ASCI had two main foci: reliability and validity. This study provided evidences for good reliability and validity of ASCI V2 scores. Reliability was estimated by satisfying internal consistency and test-retest reliability. The two-factor (“intellectual accessibility” and “emotional satisfaction”) correlated structure was supported by confirmatory factor analysis. The two subscales could be indicators of cognition and affect components of attitude, and thus we can make good connection with theoretical framework in psychology. As regards to attitude-achievement relationship, other than the well-known aptitude test score, students’ attitude played a significant role in predicting final achievement in General Chemistry course. Implications for science education were discussed.

Images, Diagrams and Metaphors in Science - The Case of Chemistry (1999)

by Michael May

Michael May: "Images, diagrams and metaphors in science and science education: The case of chemistry." Almen Semiotik, Vol. 14 (1998) p. 77-102.

Process design for the production of protein from rape seed meal

by Moges Ashagrie Retta

Publication of my Bsc thesis on national journal

This project presents the process design of the extraction of good quality protein from cheap, commercially available... more This project presents the process design of the extraction of good quality protein from cheap, commercially available rapeseed meal using food grade table salt and tap water at room temperature. The demand, the supply and growing opportunities of product application have been studied to determine the plant capacity. Laboratory scale production and testing of samples for crude protein content has been done using Micro Kjldahl apparatus. The process employed included a counter current spray drying. Finally the economic analysis has been dealt with briefly.

The Effect of Different Atomizing Gases and Drying Media on the Crystallization Behaviour of Spray-Dried Powders

by Md Imtiaz Ul Islam

M.I.U. Islam, T.A.G. Langrish (2010) The Effect of Different Atomizing Gases and Drying Media on the Crystallization Behaviour of Spray-Dried Powders, Drying Technology, Volume 28, Issue 9, Page 1035-1043.

In the Laboratory-Replication and Compression of Bulk and Surface: Structures with Polydimethylsiloxane Elastomer

by Camilo Calderon

Chemistry With Refrigerator Magnets: From Modeling of Nanoscale Characterization to Composite Fabrication

by Camilo Calderon

Scholar: 13 times

Flexible sheet refrigerator magnets (RMs) have interesting magnetic structures that allow them to be used to... more Flexible sheet refrigerator magnets (RMs) have interesting magnetic structures that allow them to be used to demonstrate a number of chemical principles. RMs are a composite of strontium ferrite dispersed in the elastomer Hypalon. The magnetic alignment of the ferrite particles gives rise to a striped array of alternating north and south poles on the back side of the RM that may be visualized by a number of techniques and altered with a strong magnet. When the back sides of two RMs are rubbed against each other, the magnets may slide or alternately attract and repel one another ("chatter"), depending on their relative orientation. These effects lend themselves to demonstrations of scanning probe microscopy and models of mechanical properties of metals and salts. Concepts of composite materials and surface chemistry may be illustrated with student laboratory fabrications of refrigerator magnets utilizing strontium ferrite dispersed in polydimethylsiloxane elastomer.

Replication and Compression of Bulk Surface Structures with Polydimethylsiloxane Elastomer

by Camilo Calderon

Scholar: 65 times

This paper describes simple classroom demonstrations and laboratory experiments based on properties of... more This paper describes simple classroom demonstrations and laboratory experiments based on properties of polydimethylsiloxane (PDMS). PDMS is a colorless, transparent elastomer. Spheres cast from PDMS can be cross-linked to varying extents to affect their rigidity, as seen in their ability to bounce when dropped. PDMS recently has been used by Whitesides et al. to replicate submicron-scale patterns by casting a negative relief image from a master template, and to progressively reduce the dimensions of these patterns through cycles based on mechanical compression. Curing PDMS in contact with features pressed into aluminum foil transfers the foil features to the elastomer. The raised surface features of the resulting cured PDMS block can transfer ink images to paper in a fashion that is similar to microcontact printing processes. Stretching or compressing the block will alter the dimensions of the transferred image. Curing PDMS in contact with the microscopic features on optical transform slides can transfer the slide features to the elastomer. The feature spacings, altered by stretching or compressing the elastomer, can be determined through the optical transform experiment. Moreover, when the elastomer is suitably compressed, the features, now with reduced dimensions, can be transferred first to an epoxy resin and then to a new sample of PDMS, representing a cycle that can lead to progressively reduced feature spacings.