Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Computer Sciences (2742)
- Chemistry (1409)
- Physics (1154)
- Engineering (1129)
- Earth Sciences (835)
-
- Geology (630)
- Statistics and Probability (571)
- Mathematics (548)
- Environmental Sciences (515)
- Life Sciences (433)
- Oceanography and Atmospheric Sciences and Meteorology (374)
- Applied Mathematics (324)
- Electrical and Computer Engineering (312)
- Biochemistry, Biophysics, and Structural Biology (238)
- Optics (235)
- Biochemistry (229)
- Information Security (212)
- Astrophysics and Astronomy (204)
- Artificial Intelligence and Robotics (183)
- Operations Research, Systems Engineering and Industrial Engineering (183)
- Biostatistics (163)
- Atomic, Molecular and Optical Physics (161)
- Computer Engineering (160)
- Software Engineering (144)
- Atmospheric Sciences (137)
- Aerospace Engineering (132)
- Meteorology (130)
- Databases and Information Systems (129)
- Signal Processing (124)
- Institution
-
- Air Force Institute of Technology (2450)
- Brigham Young University (1971)
- University of South Carolina (944)
- Virginia Commonwealth University (766)
- University of Texas Rio Grande Valley (480)
-
- Florida Institute of Technology (402)
- University for Business and Technology in Kosovo (399)
- University of North Dakota (347)
- University of Arkansas Little Rock (301)
- Mississippi State University (198)
- Illinois State University (150)
- Columbus State University (130)
- Rowan University (93)
- American University in Cairo (66)
- City University of New York (CUNY) (46)
- SASTRA Deemed to be University (24)
- St. John's University (16)
- Nova Southeastern University (7)
- Pepperdine University (3)
- Texas A&M International University (3)
- Utah State University (3)
- Keyword
-
- Machine learning (192)
- Physical Sciences and Mathematics, Chemistry (84)
- #antcenter (81)
- Deep learning (79)
- Geology (69)
-
- Machine Learning (60)
- Pure sciences (60)
- Artificial intelligence (51)
- Software engineering (51)
- Chemistry (47)
- Computer networks--Security measures (47)
- Simulation (46)
- Algorithms (45)
- Synthesis (45)
- Computer security (44)
- Computer vision (42)
- Nanoparticles (41)
- Optimization (41)
- Image processing (39)
- Mathematics (37)
- Remote sensing (37)
- Mass spectrometry (36)
- Adaptive optics (35)
- Cybersecurity (35)
- Catalysis (34)
- Security (34)
- Applied sciences (33)
- Neural networks (32)
- Neural networks (Computer science) (32)
- Classification (30)
- Publication Year
- File Type
Articles 8521 - 8550 of 8799
Full-Text Articles in Physical Sciences and Mathematics
Macrocyclic Polyether Sulfide Syntheses :|Bthe Preparation Of Thia-Crown-6, 7, And 8 Compounds, Robert Askew Reeder
Macrocyclic Polyether Sulfide Syntheses :|Bthe Preparation Of Thia-Crown-6, 7, And 8 Compounds, Robert Askew Reeder
Theses and Dissertations
Macrocyclic polyether sulfides have been prepared by reacting an oligoethylene glycol dichloride with a dithiol in refluxing basic ethanol. The following new compounds were prepared: 1,5-dithia-(19- crown-6), 3-hydroxy-1,5-dithia-(19-crown-6), 1,4-dithia-(21-crown-7), 3-hydroxy-1,5-dithia-(22-crown-7), and 1,4-dithia-(24-crown-8). One other previously reported macrocyclic polyether sulfide was also prepared. The thesis includes a review of macrocyclic sulfides and other related compounds, the thermodynamics of interaction of several macrocyclic polyether sulfides with Ag^+, Hg^2+, and Pb^2+ ions, and a discussion of the structure of these materials.
A Comparative Investigation Of Mammalian Serine Transhydroxymethylases, Sanha Panichajakul
A Comparative Investigation Of Mammalian Serine Transhydroxymethylases, Sanha Panichajakul
Theses and Dissertations
Serine transhydroxymethylase was purified one thousand-fold from bovine brain and one hundred and twenty-fold from bovine liver. Both enzymes were yellow due to the presence of the coenzyme pyridoxal 5'-phosphate. Polyacrylamide gel electrophoresis of the liver enzyme showed one major band containing 95% of the protein, while in the case of the brain enzyme two major bands of nearly equal intensity were observable. The specific activity of the crude liver enzyme was about sixty times higher than that of brain. The liver enzyme was also more heat stable than the brain enzyme. The purified enzymes exhibited L-allothreonine and L-threonine aldolase …
The Kinetics And Mechanism Of A Free Radical Decay In Aqueous Solution, Denzel Lee Fillmore
The Kinetics And Mechanism Of A Free Radical Decay In Aqueous Solution, Denzel Lee Fillmore
Theses and Dissertations
The decomposition of nitrosyl disulfonate ion was studied in strongly alkaline solution of 10-2 to 5 m sodium hydroxide. The decomposition was found to be first-order in both hydroxide and nitrosyl disulfonate ions. A multi-step mechanism involving sulfite ion, sulfite ion radical and nitrosyl monosulfonate ion radical as intermediates was proposed, with the initiating step being the SN2 replacement of a sulfite ion by a hydroxide ion. The rate constant for the initiating step ranged from 1.2 x 10-7 to 2.25 x 10-5 M-1s-1 for the solution concentration range of the study. The products of the decomposition were identified as …
Composition, Time, And Size Distributions Of Airborne Particulate Material In Utah Valley, Douglas R. Lawson
Composition, Time, And Size Distributions Of Airborne Particulate Material In Utah Valley, Douglas R. Lawson
Theses and Dissertations
The Lundgren impactor is used to determine the variations in time and size distributions of particulate matter in Utah Valley. Charged particle X-ray fluorescence is employed in this study to determine elemental concentrations. Air samples are taken during two 24-hour periods in downtown Provo, 24 hours near U.S. Steel Corporation, Geneva Works, and 12 hours at Lindon Elementary School, and diurnal particulate variations are compared. The amounts of lead and bromine are four times greater on a weekday than on a Sunday in downtown Provo, suggesting the effect of the automobile on atmospheric particulate concentrations. Paraffin coated impaction surfaces are …
Development Of Proton-Induced X-Ray Emission Techniques With Application To Multielement Analyses Of Human Autopsy Tissues And Obsidian Artifacts, Kirk Kay Nielson
Development Of Proton-Induced X-Ray Emission Techniques With Application To Multielement Analyses Of Human Autopsy Tissues And Obsidian Artifacts, Kirk Kay Nielson
Theses and Dissertations
A method of trace element analysis using proton-induced X-ray emission (PIXE) techniques with energy dispersive X-ray detection methods is described. Data were processed using the computer program ANALEX. PIXE analysis methods were applied to the analysis of liver, spleen, aorta, kidney medulla, kidney cortex, abdominal fat, pancreas and hair from autopsies of Pima Indians. Tissues were freeze dried and low temperature ashed before analysis. Concentrations were tabulated for K, Ca, Ti, Mn, Fe, Co, Ni, Cu, Zn, Pb, Se, Br, Rb, Sr, Cd and Cs and examined for significant differences related to diabetes. Concentrations of Ca and Sr in aorta, …
Use Of Selected Macroinvertebrates As Indicators Of Sedimentation Effects On Huntington River, Utah, Michael Kenneth Reichert
Use Of Selected Macroinvertebrates As Indicators Of Sedimentation Effects On Huntington River, Utah, Michael Kenneth Reichert
Theses and Dissertations
Benthic macroinvertebrate communities of Huntington River, Emery County, Utah were studied to determine effects of sedimentation from construction of Electric Lake Dam, a state highway, and two bridges. Approximately 900 benthic samples were collected from riffle areas above, in, and below the construction zone from January, 1971 to December, 1973. Two settling basins below construction sites were effective in limiting scouring of downstream communities. Heavy silt deposition was limited to a 1-km stream reach. Number of indicators, density, and biomass were reduced in the construction zone during periods of sediment input. During periods of scouring, density and biomass were reduced; …
The Historical Development Of Wasatch Trails In Salt Lake County, Clyde Brian Hardy
The Historical Development Of Wasatch Trails In Salt Lake County, Clyde Brian Hardy
Theses and Dissertations
In this study investigation was made concerning the etiology of the foot trails that thread their way through Wasatch Forest lands in Salt Lake county. The time delimitation was 1847 to 1975.
The origin of the majority of these trails dates back to the nineteenth century and is closely tied to the efforts of pioneers who labored to wrest a living from semi-arid land. Early lumbering, livestock operations, mining activities, water collection systems, and pioneer recreation all provided impetus for trail development. In a sense these trails are a kind of anthology of human endeavor.
Passing into the twentieth century …
Pleistocene Geology Of The Grand Forks-Bemidji Area, Northwestern Minnesota, Kenneth L. Harris
Pleistocene Geology Of The Grand Forks-Bemidji Area, Northwestern Minnesota, Kenneth L. Harris
Theses and Dissertations
This is a report of a reconnaissance study of the Quaternary geology of an area in northwestern Minnesota. Surface geology was studied in an area extending from Grand Forks, North Dakota, in the northwest to Bemidji, Minnesota, in the southeast, an area of 10 723 square kilometres (4140 square miles). Near-surface stratigraphy was studied in the area of surface study and an adjacent area of equal size to the south.
Surface materials mapped range in age from Pleistocene to Holocene and include glacial, glaciofluvial, lacustrine, bog, eolian, and alluvial sediments.
Sixteen power-auger test holes, two measured sections along the Red …
Geology Of The North Beulah, Center, And Glenharold Lignite Mines In Mercer And Oliver Counties, Southwestern North Dakota, Roy E. Kulland
Geology Of The North Beulah, Center, And Glenharold Lignite Mines In Mercer And Oliver Counties, Southwestern North Dakota, Roy E. Kulland
Theses and Dissertations
The geology of the North Beulah, Center, and Glenharold lignite mines in Mercer and Oliver Counties, southwestern North Dakota, were examined. Stratigraphically, all mines lie within the Sentinel Butte Formation. The North Beulah Mine lies 70 m below the top of the Sentinel Butte Formation and the Center and Glenharold Mines lie about 80 m above the base of the Tongue River Formation.
Four sedimentary types are recognized arid common to all mines; these are: silt and clay, silty sand, sand, and lignite. The silt and clay were deposited in floodbasins and shallow lakes occupying the lowest parts of the …
Late Pleistocene And Holocene Geology Of The Moe Site, New Town, North Dakota, Richard W. Kornbrath
Late Pleistocene And Holocene Geology Of The Moe Site, New Town, North Dakota, Richard W. Kornbrath
Theses and Dissertations
Eight stratigraphic units of Late Cenoioic age are present around the Moe Archeological Site near New Town, North Dakota. Unit Zero is a layer of glacial sediment consisting of grayish brown pebbly clay loam. Unit One consists of fluvial and beach sand and gravel. Unit Two consists of light yellowish brown, offshore lake silt that was deposited into a glacial lake in Late Wisconsinan time. Unit Three is a layer of glacial sediment consisting of grayish brown pebbly clay loam (Late Wisconsinan). Unit Four consists of fluvial sand and gravel (Late Wisconsinan}. Unit Five is a layer of slough sediment …
Stratigraphy Of The Upper Part Of The Fort Union Group In Southwestern Mclean County, North Dakota, Leroy A. Hemish
Stratigraphy Of The Upper Part Of The Fort Union Group In Southwestern Mclean County, North Dakota, Leroy A. Hemish
Theses and Dissertations
Southwestern McLean County is an area characterized by glacial topography and glacially-modified bedrock topography, with limited exposures of bedrock. Outcropping bedrock formations include the Cannonball, Tongue River, and Sentinel Butte Formations, all in the Fort Union Group of Paleocene age.
The Cannonball Formation crops out only in the southeastern part of the area studied (at Washburn), where 18 feet of laminated, gray-brown sandy mudstone is exposed. A yellow-brown, cross-bedded sand unit directly overlies the mudstone. I have tentatively selected the base of this sand unit, which is present in the subsurface throughout southwestern McLean County and reaches thicknesses of more …
Glacial Stratigraphy Of Northeastern North Dakota, Howard Hobbs
Glacial Stratigraphy Of Northeastern North Dakota, Howard Hobbs
Theses and Dissertations
Seven lithostratigraphic units (formations} composed dominantly of glacial sediment have been recognized in northeastern North Dakota. Three formations, the Falconer Formation (Harris and others, 1974}, the Dahlen, and Gardar Formations (Salomon, 1975). Have been previously recognized. Four formations, the Hansboro, Vang, Tiber and Cando Formations are newly recognized. Uncorrelated units of glacial sediment are described but not named. The formations are differentiated and correlated primarily by the proportion of crystalline (igneous and metamorphic rock fragments), carbonate, and shale grains in the coarse sand fraction (1 to 2 mm) of the glacial sediment. The proportion of shale grains was. Found to …
Petrography Of Precambrian Iron Formation, Pembina County, North Dakota, Ronald E. Richardson
Petrography Of Precambrian Iron Formation, Pembina County, North Dakota, Ronald E. Richardson
Theses and Dissertations
In October of 1964 the Topographic Branch of the United States Geological Survey reported difficulties in using magnetic compasses while mapping in the areas of Akra and Hensel, Pembina County, North Dakota. University of North Dakota geologists located anomalies of 67,500 gammas 1.6 lon east of Akra and 71,500 gammas 4 km east of Hensel, the normal magnetic field in this area being about 60,000 gammas. The rock bodies producing the magnetic anomalies were drilled and examination of diamond drill core showed them to consist of oxide and silicate facies iron formation interlayered with quartz-biotite schist of Precambrian age. The …
Quaternary Geology Of The Southern Part Of The Grand Forks And Bemidji Quadrangles, Donald K. Sackreiter
Quaternary Geology Of The Southern Part Of The Grand Forks And Bemidji Quadrangles, Donald K. Sackreiter
Theses and Dissertations
Northwestern Minnesota is an area at the southwestern edge of the Canadian Shield that is mantled by thick Pleistocene sediment. The Pleistocene material included a variety of glacial, shoreline, offshore, fluvial, and eolian sediment.
The lithology of the glacial sediment reflects the rock and sediment over which the depositing glacier flowed. Glaciers that advanced from the northeast (Canadian Shield) deposited sandy, granitic-rich material. Glaciers that advanced from the north· (Manitoba Lowland) deposited loamy, calcareous-rich material. Glaciers that advanced from the northwest (eastern North Dakota and southwestern Manitobal deposited clayey, shale-ridt material. A variety of fluvial and lacustrine sediments are typically …
The Keller Plan In College Introductory Physical Geology : A Comparison With The Conventional Teaching Method, Robert G. Walsh Sr.
The Keller Plan In College Introductory Physical Geology : A Comparison With The Conventional Teaching Method, Robert G. Walsh Sr.
Theses and Dissertations
The purpose of this study is to compare the learning and attitudinal changes that took place in a college introductory physical geology class between a self-paced method of instruction called the Keller Plan and the conventional lecture-laboratory method.
The sample population was 56 students enrolled in Earth Science 120, an introductory physical geology course at Minot State College ·~ during the fall quarter, 1973. An experimental section of 20 students experienced the Keller Plan treatment and two control groups consisting of 18 students each received the conventional method of instruction.
Four specific areas of investigation were tested: (1) knowledge of …
Stratigraphy Of Offshore Sediment Of Lake Agassiz, North Dakota, Michael B. Arndt
Stratigraphy Of Offshore Sediment Of Lake Agassiz, North Dakota, Michael B. Arndt
Theses and Dissertations
Lake Agassiz occupied the Red River Valley between about 13,800 and 9,000 years ago. The Late Wisconsinan ice sheet that covered the Red River Valley retreated far enough to expose the drainage divide in northern South Dakota and south-central Minnesota sometime after 14,000 B.P. and meltwater ponded behind this divide in Richland County. Before 13,800 the ice readvanced over this area and then retreated again. As the ice margin retreated northward, deposition of the Argusville and Wylie Formations took place. Sometime before 12,800 the ice advanced again into the Red River Valley as far as Traill County; the terminus of …
Natural Science Of The Great Plains As It Relates To The American Indian : A Syllabus And Sourcebook, Mary E. Bluemle
Natural Science Of The Great Plains As It Relates To The American Indian : A Syllabus And Sourcebook, Mary E. Bluemle
Theses and Dissertations
This dissertation, which includes a sourcebook of pertinent reference materials, sample lesson plans, and natural science roadlogs, is an initial attempt at providing an Indian Studies field course in natural science. It also includes a syllabus which stresses natural science processes and serves as a unifying factor for field work, lecture, and course discussions. The dissertation stresses geographical and ecological concepts, climatic and geological processes, and the natural habitats of North Dakota. It includes discussions of North Dakota vertebrates and early man and his relation to his environment; discussions of_ the geologic features, geologic history, vegetation and animal life of …
Petrology And Geochemistry Of The Killdeer Carbonates, John J. Delimata
Petrology And Geochemistry Of The Killdeer Carbonates, John J. Delimata
Theses and Dissertations
The strata of the proposed Killdeer Formation (Stone, W. J., 1972) in the Killdeer Mountains of Dunn County, North Dakota is composed of a sequence of tuffaceous, calcareous, dolomitized and silicified flat lying sedimentary rocks of Tertiary age. It is the purpose of this report to describe and integrate the petrology and geochemistry of these sediments.
Fieldwork was conducted during the summer of 1972. Forty-three stratigraphic sections were measured and representative samples of each were collected for further analysis. Seven section were selected as representative of the area, and samples from these were studied in thin section with the petrographic …
The Purification And Characterization Of Methylmalonyl Coa Mutase From Bovine Brain, Damon Martin
The Purification And Characterization Of Methylmalonyl Coa Mutase From Bovine Brain, Damon Martin
Theses and Dissertations
Methylmalonyl CoA mutase has been purified over 2300-fold from bovine brain using fractional precipitation, ion exchange resins, and gel filtration procedures. The crude extract had an equal mixture of mutase in the halo- and apoenzyme form. After the final purification step the ratio had changed to 86% holo-enzyme and 14% apoenzyme. The mutase enzyme had a pH optimum of 7. 0 in Tris-HCI buffer. The Km values for L-methylmalonyl CoA and succinyl CoA were 7.7 x 10^-4 M and 1.8 x 10^-4 M respectively. The equiIibrium constant in the direction of succinyl CoA formation was 19. Inhibition with N-ethylmalei-mide was …
Metabolism Of 3-Isopropyl-4h-2,1,3-Benzothiadiazin-4-(3h)-One-2,2-Dioxide (Bentazon) In Agitated And Non-Agitated Sediment, David Cortez Gutierrez
Metabolism Of 3-Isopropyl-4h-2,1,3-Benzothiadiazin-4-(3h)-One-2,2-Dioxide (Bentazon) In Agitated And Non-Agitated Sediment, David Cortez Gutierrez
Theses and Dissertations
Bentazon, (3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-l-2,2-dioxide) a new experimental herbicide, was studied under the effects of sterile and non-sterile conditions, 12 hours light: 12 hours dark and totally dark conditions, and agitated and non-agitated conditions in aquatic sediment. The effects of the different levels of BOD/COD values on the decomposition of Bentazon were studied. Photoperiod, sterility, and BOD/COD levels appeared to have no influence in the breakdown of Bentazon. Agitation-time interaction appeared to be the only factor that influenced the more rapid degradation of Bentazon. Bentazon was the major 14C-residue found in the water; it was followed by an unknown. The third major metabolite …
The Attack Of Hard And Soft Nucleophiles On 6-Methylsulfonyl-, 6-Methylsulfinyl-, And 6-Methylthioaminopteridines, William David Johnston
The Attack Of Hard And Soft Nucleophiles On 6-Methylsulfonyl-, 6-Methylsulfinyl-, And 6-Methylthioaminopteridines, William David Johnston
Theses and Dissertations
In an attempt to prepare 6-anilino and 6-benzylaminopteridines, 2,4,7-triamino-6-methylsulfonyl and 2,4,7-triamino-6-methylsulfinylpteridines were prepared and reacted with a number of benzylamines and aniline. These hard nucleophiles gave amine exchange products with no displacement at the 6 position. Aliphatic amines gave exchange in the 2,4-and 7-positions. The exchange occurring in the 7-position must be occurring by an AE mechanism. This is the first such exchange reported in a ring other than a 1,3-azine. Aniline gave no exchange product except in an acid catalyzed reaction, and then gave exchange in only the 2 and 4-positions. Numerous reactions on related substrates, are reported. Soft …
Part I. Catalytic Hydrocarbon Reforming By Technetium Catalysts.|Npart Ii.|Pacetone Azine And 3,5,5-Trimethyl-2-Pyrazoline Adducts Of Palladium Chloride, James Lynn Palmer
Part I. Catalytic Hydrocarbon Reforming By Technetium Catalysts.|Npart Ii.|Pacetone Azine And 3,5,5-Trimethyl-2-Pyrazoline Adducts Of Palladium Chloride, James Lynn Palmer
Theses and Dissertations
Technetium catalyzes hydrocarbon reforming reactions of dehydrocyclization, isomerization, hydrogenolysis, and coke formation. A kinetic equation was derived and E_a and A_o evaluated for dehydrocyclization of n-heptane, isomerization of n-pentane, and dehydrogenation of methylcyclohexane and cyclohexane. The results were related to the metal, the form of the catalyst, catalyst support, and the deactivation of the catalyst. The effect of sulfur compounds was determined. No residual radioactivity in the product was observed. The ligands, acetone azine (AA) and 3,5,5-trimethyl-2- pyrazoline (Py), reacted with (C_6H_5CN)_2PdCl_2 to form adducts, L_2PdCl_2 and (LPdCl_2)_n. Their structures were characterized by spectroscopic methods and some molecular weights determined. …
Thermodynamic Stability Constants Of Silver Bromide Complexes In Water And Water-Acetone Mixtures Determined By Ion-Selective Electrode Measurements, Arthur Lee Cummings
Thermodynamic Stability Constants Of Silver Bromide Complexes In Water And Water-Acetone Mixtures Determined By Ion-Selective Electrode Measurements, Arthur Lee Cummings
Theses and Dissertations
Thermodynamic equilibrium constants for silver(I) bromide complexes were determined by ion-selective membrane electrode potential measurements in water and in mixtures of water and acetone of approximately 5, 10 and 15 percent acetone by weight. Values of the solubility product constant were determined in each solvent system by calibration of a silver bromide membrane electrode with silver nitrate solutions and with sodium bromide solutions. Stability constants of silver(I) bromide complexes were determined using a silver ion-selective, silver sulfide membrane electrode in unsaturated solutions in which the formal concentrations of silver(I) and of bromide ranged from approximately I x 10-8 to 7 …
A Remote Aerosol Sampler To Be Used With Charged-Particle X-Ray Fluorescence Analysis, Steven Dee Rowley
A Remote Aerosol Sampler To Be Used With Charged-Particle X-Ray Fluorescence Analysis, Steven Dee Rowley
Theses and Dissertations
A remote aerosol sampler, capable of up to 3 weeks continuous sampling has been developed. It consists of an Anderson 2000 Inc. mini-sampler or personnel monitor requiring an air flow of 1.4 e/min, a flow meter, a vacuum meter, a bleed valve, a dry gas volume meter, and a pump. The pump is a Brailsford Model TD-4X2, and operates on a 24 volt D.C. power supply. The sampler consists of four impaction stages with a 0.4 μ Nuclepore backup filter. Particulates are removed from the plates in an ultrasonic cleaner with hexane solvent. The suspended particulates are collected on a …
The Benthic Communities Of The Eastern Rocky Shore Areas Of Goshen Bay, Utah Lake, Thomas Whitney Toole
The Benthic Communities Of The Eastern Rocky Shore Areas Of Goshen Bay, Utah Lake, Thomas Whitney Toole
Theses and Dissertations
Information about the benthic macroinvertebrate populations along the eastern shore of Goshen Bay, Utah Lake, Utah, can be used, in part, to determine future management of the lake. In the project herein reported, cement artificial substrate samplers were used to sample two types of substrate: rubble and compacted calcareous tufa. Monthly samples were obtained from each type of substrate from March 1972 to May 1973. An amphipod, Hyalela azteca and a chironomid, Dicrotendipes fumidus were the dominant organisms in numbers and tiomass. Amphipod numbers were dependent upon the amount of algal standing crop. Elimination of this area could affect the …
Macrocyclic Polyether Sulfide Syntheses, The Preparation Of Thia-Crown-3, 4, 6, And 7 Compounds, Yau-Kwong Joseph Hui
Macrocyclic Polyether Sulfide Syntheses, The Preparation Of Thia-Crown-3, 4, 6, And 7 Compounds, Yau-Kwong Joseph Hui
Theses and Dissertations
Macrocyclic polyether sulfides have been prepared by reacting an oligoethylene glycol dichloride with a dithiol or sodium sulfide in ethanol. The following new compounds were prepared: 1-thia-(9-crown-3), 1,4-dithia-(9-crown-3), 1,4-dithia-(12-crown-4), 1,4,7-trithia-(12-crown-4), 1-thia-(18-crown-6), I,4-dithia-(18-crown-6), 1,7-dithia-(18-crown-6), 1,4,7-trithia-(18-crown-6), 1,7-dithia-(21-crown-7), 1,4,7-trithia-(21-crown-7). Four other previously reported macrocyclic polyether sulfides were also prepared. The symmetry of the nmr spectra of these compounds give added evidence for the proposed ring structures. The following subjects were presented and discussed: studies of cyclization by-products, dependence of cyclization yield on the size of the rings, high dilution principle and its application, medium-sized rings, effect of hetero-atoms on cyclization and melting point …
The Solution Photochemistry Of Benzaldehyde In Benzene, Ethanol, And 1-Hexyne, Ronald Douglas Knudsen
The Solution Photochemistry Of Benzaldehyde In Benzene, Ethanol, And 1-Hexyne, Ronald Douglas Knudsen
Theses and Dissertations
The photoreactions of benzaldehyde in benzene, ethanol, and 1-hexyne have been studied. Irradiation of benzaldehyde in benzene produces benzoin (I), hydrobenzoin (II), and deoxybenzoin (III). Irradiation of benzoin (I) in this solvent results in benzaldehyde formation as well as small amounts of (II) and (III). The ethanol irradiation of benzaldehyde resulted, predominantly, in the formation of (II) with (I) formed in small amounts. The photolysis of benzaldehyde in 1-hexyne produces (I), (II), (III) cis-2-heptenophenone (VII), trans-2-heptenophenone (VIII), heptanophenone (IX), and 2-(n-butyl)- 1,4-diphenyl-1,4-butanedione (X). Mechanistic pathways for the formation of these photoproducts are discussed. Separation and characterization of cis- and trans-2- …
A Calorimetric Study Of Metal Binding In Carboxypeptidase, Carbonic Anhydrase And Concanavalin A, Gary E. Hatch
A Calorimetric Study Of Metal Binding In Carboxypeptidase, Carbonic Anhydrase And Concanavalin A, Gary E. Hatch
Theses and Dissertations
The purpose of this study was to perfect a new calorimetric method for identifying and counting ionizable chemical groups on proteins. To do this, calorimetric and electrometric titrations were performed (using HCl and NaOH as titrant) on native carboxypeptidase, carbonic anhydrase and concanavalin A plus their apo and organic ligand bound derivatives. Readily identifiable endpoints were seen in the calorimetric titrations and general agreement was found between ΔH values obtained in this study and literature ΔH values of model compounds undergoing the same reaction. Imidazole groups were those most easily counted. Many assumptions had to be made, however, in concluding …
Trace Metal Analysis Of Hair By Charged Particle X-Ray Fluorescence, George M. Allison
Trace Metal Analysis Of Hair By Charged Particle X-Ray Fluorescence, George M. Allison
Theses and Dissertations
A method for the trace element analysis of hair by charged particle X-ray fluorescence is presented. The validity of the method is shown by the analysis of NBS SRM 1577--Bovine Liver, obtained from the National Bureau of Standards. Excellent correlation is obtained between results from the analysis by the X-ray method and those certified by NBS. Hair samples are ashed by a low temperature oxidation process and analyzed by the X-ray method. The results from the analysis by the X-ray method are compared to those obtained from the analysis of the same hair samples by atomic absorption. Good correlation is …
The Mormon Role In Irrigation Beginnings And Diffusions In The Western States: An Historical Geography, Kelly C. Harper
The Mormon Role In Irrigation Beginnings And Diffusions In The Western States: An Historical Geography, Kelly C. Harper
Theses and Dissertations
Irrigation has played an important part in the development of the Western States. Its beginnings have often been associated with the Mormon settlement in Utah. However, irrigation had its inception in the West long before the Mormons came to the Great Basin in 1847. The spatial extent of irrigation before this date included limited acreage in nearly every Western State.
Before their arrival in the Great Basin the Mormons had become acquainted with irrigation methods. Knowledge of irrigation had diffused to them primarily from the Spanish in the Southwest. Thus, they were well prepared to begin their irrigation enterprises in …