Catalytic Calcination of Calcium Carbonate (open access)

Catalytic Calcination of Calcium Carbonate

The calcination of calcium carbonate in a cement or a lime kiln uses approximately two to four times the theoretical quantity of energy predicted from thermodynamic calculation depending upon the type of the kiln used (1.4 x 10^6 Btu/ton theoretical to 6 x 10^6 Btu/ton actual). The objective of this research was to attempt to reduce the energy required for the calcination by 1. decreasing the calcination temperature of calcium carbonate, and/or 2. increasing the rate of calcination at a specific temperature. Assuming a catalytic enhancement of 20 percent in the industrial applications, an energy savings of 300 million dollars annually in the United States could be reached in the cement and lime industries. Three classes of compounds to date have shown a positive catalytic effect on the calcination of calcium carbonate. These include alkali halides, phospho- and silico-molybdate complexes, and the fused carbonates system.
Date: August 1985
Creator: Safa, Ali Ibrahim, 1953-
System: The UNT Digital Library
Teaching First-Semester General Chemistry Using 3D Video Games following an Atoms First Approach to Chemistry (open access)

Teaching First-Semester General Chemistry Using 3D Video Games following an Atoms First Approach to Chemistry

The unified learning model (ULM) focuses on students' engagement, motivation, prior knowledge, and working memory. This study employs the use of video games to assess students' learning through a 3D chemistry gaming environment. In this human-subjects research, students carried out missions and applied reasoning to solve problems appropriate for general chemistry content. For learning to occur, students must be engaged and motivated as stated in the ULM. Learning cannot necessarily be accomplished by experience alone, and critical thinking is required to turn the experience into learning. The interpretation of educational theory applied to video games and this proposed study are discussed. A moderately positive correlation was found between exam score and study time (playing the game). Essentially the more time spent playing the game or an online activity the higher the exam scores. There was an alpha level less than 0.05 (p < 0.05) between the experimental group and non-traditional group (no game or online activity). Supporting that there was a statistically significant difference between groups, the null hypothesis was accepted between the game and online activity. Furthermore, as stated under the ULM, engagement is necessary for optimal learning.
Date: August 2018
Creator: Jenkins, Dave A
System: The UNT Digital Library
A Study of the Synthesis and Reactions of Enol Lactones (open access)

A Study of the Synthesis and Reactions of Enol Lactones

The purpose of this investigation was to study the syntheses of enol lactones and to prepare a series of amide derivatives of these compounds.
Date: August 1959
Creator: Papalos, John George
System: The UNT Digital Library
Simultaneous Part-Per-Billion Determination of Sodium and Chloride Ions (open access)

Simultaneous Part-Per-Billion Determination of Sodium and Chloride Ions

The method utilizes both cation and anion concentrator columns in parallel as a preconcentration system. The preconcentrator system is loaded using a reagent delivery module operated for a specific time at a preset flow rate. Total injection volumes of 2-5 ml are routinely used. Various chromatograms are discussed along with detailed information concerning detection limits for sodium and chloride, the system operating conditions, and the solutions to other pitfalls which have arisen during the course of this work.
Date: August 1987
Creator: Gan, Din-Chung
System: The UNT Digital Library
Podcast Effectiveness as Scaffolding Support for Students Enrolled in First-Semester General Chemistry Laboratories (open access)

Podcast Effectiveness as Scaffolding Support for Students Enrolled in First-Semester General Chemistry Laboratories

Podcasts covering essential first-semester general chemistry laboratory techniques and central concepts that aid in experimental design or data processing were prepared and made available for students to access on an as-needed basis on iPhones- or iPod touches-. Research focused in three areas: the extent of podcast usage, the numbers and types of interactions between instructors and research teams, and student performance on graded assignments. Data analysis indicates that the podcast treatment research teams accessed a podcast 2.86 times on average during each week that podcasts were available. Comparison of interaction data for the lecture treatment research teams and podcast treatment research teams reveals that interactions with instructors were statistically significantly fewer for teams that had podcast access rather than a pre&#8208;laboratory lecture. The implication of the results is that student research teams were able to gather laboratory information more effectively when it was presented in an on-demand podcast format. Finally, statistical analysis of data on student performance on graded assignments indicates no significant differences between outcome measures for the treatment groups when compared as cohorts. The only statistically significant difference is between students judged to be highly motivated; for this sub&#8208;group the students in the podcast treatment group earned a …
Date: August 2010
Creator: Powell, Mary Cynthia Barton
System: The UNT Digital Library