Development and application of artificial intelligence strategies to solve infrared spectroscopic problems

The ever-increasing power of modern infrared instrumentation, coupled with the decreasing number of experienced spectroscopists has created an imbalance between information generation and interpretation capabilities. At the same time, digital computers are being developed which continue to grow in storage and processing capabilities, and shrink in cost. Clearly, the computer may serve as a valuable tool to aid the analytical chemist in interpreting spectroscopic information. This dissertation deals with the development of new approaches to exploiting computer technology to interpret infrared spectroscopic data. A large existing expert system for functional group analysis, PAIRS, has been modified to transfer the maximum amount of information to the chemist. Two closely coupled knowledge based systems, IRBASE and MIXIR, have been created to identify major components of condensed phase mixtures. A second version of MIXIR has been developed to identify major components of vapor phase mixtures. Finally, a neural network approach to peak detection in analytical data has been developed

Merged electrospray ionization mass spectrometry

Ambient ionization allows the analysis of materials in their native environment without sample preparation by creating ions outside the mass spectrometer. The goal of this research was to develop new ambient ionization techniques for application to solids, liquids and particles under ambient conditions. Samples to be analyzed were directly merged with an electrospray of droplets, and then ionized and detected by a mass spectrometer. An ion trap mass spectrometer was modified with a nanoelectrospray source and configured for three experiments: merged electrospray ionization of dry particles, merged electrospray ionization of combustion products, and infrared laser desorption/ablation using electrospray for post-ionization. In the first set of experiments, materials in powdered samples were ionized directly by interaction with an electrospray of charged solvent droplets. The powdered samples were dispersed as dry particles with an aerosol generator. The study included amino acids and antibiotics, as well as food and pharmaceutical samples. Singly-charged peaks, corresponding to major components in the powdered samples, were detected using this method. The second set of experiments directly analyzed combustion products generated from the burning of cigarettes, incense, candles, and organic fuels by merging these with electrospray for ionization. This approach allowed the detection of major components in the smoke of cigarettes, incense, and candles, and polycyclic aromatic hydrocarbons generated from combustion of organic fuels. In the third set of experiments, an infrared laser was used to desorb and ablate samples placed on a stainless steel sample target, and electropray droplets interacted with the ablated materials to generate ions. Protein standards, biological fluids, and pharmaceutical products were analyzed using this technique. The spectra of the materials analyzed were similar to conventional electrospray

Measurement techniques and instruments suitable for life-prediction testing of photovoltaic arrays

Array failure modes, relevant materials property changes, and primary degradation mechanisms are discussed as a prerequisite to identifying suitable measurement techniques and instruments. Candidate techniques and instruments are identified on the basis of extensive reviews of published and unpublished information. These methods are organized in six measurement categories - chemical, electrical, optical, thermal, mechanical, and other physicals. Using specified evaluation criteria, the most promising techniques and instruments for use in life prediction tests of arrays were selected

Analytical Methods of Isolation and Identification

The chemical constituents of plants are complicated, and monomeric compounds must be obtained via extraction and isolation before structure identification, bioactivity screening, and so on. In recent years, the new technologies and methods of the extraction, isolation, and structural identification have come forth, which promote the speed of extraction and analysis of phytochemicals. The chemical structures of compounds from plants must be identified or elucidated, which may provide the necessary basis for further study on the bioactivities, structure-activity relationships, metabolisms in vivo, structural modification, and synthesis of the active compounds. The amount of chemical constituents isolated from plants is often minor, so the structural studies are often difficult to carry out with classical methods. Therefore, spectral analysis is mainly used. This chapter describes the isolation and identification methods during the study of phytochemicals

Effect of curing conditions and harvesting stage of maturity on Ethiopian onion bulb drying properties

The study was conducted to investigate the impact of curing conditions and harvesting stageson the drying quality of onion bulbs. The onion bulbs (Bombay Red cultivar) were harvested at three harvesting stages (early, optimum, and late maturity) and cured at three different temperatures (30, 40 and 50 oC) and relative humidity (30, 50 and 70%). The results revealed that curing temperature, RH, and maturity stage had significant effects on all measuredattributesexcept total soluble solids

Study of Flavonoids and Oils from Some Medicinal Plants

هدفت الدراسة الى استخلاص زيت بذور بعض النباتات الطبية و دراسة الخواص الفيزوكيميائية للزيت المستخلص، بالاضافة الي التحقق من نوع الفلفونيد الموجود في نبات الشمار. اوضحت الخواص الفيزوكيميائية للزيت المستخلص من نبات ابو ليلى ان اللزوجة 56 سنتي بويز، و الكثافة 0.915 جم/مل، و معامل الانكسار 1.470،,ورقم اليود150.74مل/جم، اللون اصفر / احمر 2.30/0.105و رقم البيروكسيد 63.87 مل/مج، و قيمة الحموضة 3.88 مل/جم، و رقم التصبن 160.58مل/جم. بالاضافة نتائج تحليل كروماتوغرافيا الغاز – مطياف الكتلة اوضحت ان الزيت يحتوي علي 17 مكونا كيميائيا و السائد منها (9, 12-Octadecadienoic acid (Z, Z)-, methyl ester (29.23%), 9-octadecenoic acid (Z)-, methyl ester (21.69%), hexadecanoic acid, methyl ester (17.85%), methyl stearate (14.80%)). اظهرت الخواص الفيزوكيميائية لنبات العرد ان اللزوجة 53 سنتيبويز، و الكثافة 0.917 جم/مل، و معامل الانكسار 1.473،رقم اليود 176.74مل/جم، اللون اصفر /احمر 33.35/0.00و رقم البيروكسيد 123.7مل/مج، و قيمة الحموضة 1.63مل/جم، و رقم التصبن 94.421 مل/جم. كما اظهرت نتائج تحليل كروماتوغرافيا الغاز- مطياف الكتلة ان الزيت يحتوي علي 24 مكونا و السائدة منها (9, 12 octadecadienoic acid (Z, Z)-, methyl ester (29.23%),9-octadecenoic acid (Z)-, methyl ester (21.69%), hexadecanoic acid, methyl ester (17.85%)). كما اظهرت الخواص الفيزوكيميائية لنبات الكول ان اللزوجة 58 سنتيبويز، و الكثافة 0.915 جم/مل، و معامل الانكسار 1.472 ورقم اليود 167.41مل/جم، اللون اصفر/ احمر 10.105/0.00 رقم البيروكسيد 81 جم/مج، و قيمة الحموضة 6.41 مل/جم، و رقم التصبن 152.05مل/جم. كما اظهرت نتائج تحليل كروماتوغرافيا الغاز- مطياف الكتلة ان الزيت يحتوي علي 16 مكونا و السائدة منها (9,12-octadecadienoic acid (Z, Z)-, methyl ester (38.75%), hexadecanoic acid, methyl ester (18.50%);methyl stearate (10.98%), 9-octadecenoic acid (Z)-, methyl ester (10.67%)). و كذلك اظهرت الخواص الفيزوكيميائية لنبات الزان ان اللزوجة 52 سنتيبويز، و الكثافة 0.917 جم/مل، و معامل الانكسار 1.471،ورقم اليود 159.21مل/جم واللون اصفر/ احمر10.10/1.40 رقم البيروكسيد 37.698مل/مج، و قيمة الحموضة 2.511مل/جم، و رقم التصبن176.361مل/جم. كما اظهرت نتائج تحليل كروماتوغرافيا الغاز- مطياف الكتلة ان الزيت يحتوي علي 16 مكونا و السائدة منها (9, 12-octadecadienoic acid (Z, Z)-, methyl ester (35.74%), hexadecanoic acid, methyl ester (24.22%), methyl stearate (15.27%), 9-octadecenoic acid (Z)-, methyl ester (12.14%).). اضافتا اظهرت الخواص الفيزوكيميائية لزيت بذور نبات الجرجير ان اللزوجة 58سنتيبويز، و الكثافة 0.916جم/مل، و معامل الانكسار 1.473 ورقم اليود 176.41مل/جم واللون اصفر / احمر 43.2/0.00 ورقم البيروكسيد 1.984مل/مج، و قيمة الحموض

Etching of CVD diamond surfaces

This thesis presents a fundamental study on etching of diamond surfaces. Details of the growth by microwave plasma Chemical Vapour Deposition (CVD) and etching by microwave hydrogen plasma, oxygen reactive ion etching (RIE) and thermal oxidation are presented. Prolonged exposure of {100} diamond surfaces to microwave hydrogen plasma was investigated by atomic force microscopy (AFM). Reduction of surface roughness has been observed while formation of etch pits has not been detected. X-ray photoelectron spectroscopy (XPS) detected the removal of graphitic carbon and reduction of oxygen under hydrogen plasma etching. Electrical sheet resistivity has been observed to be depended on the texture of the CVD diamond films as well as on the ambient exposure time. Both the surface and electronic properties are shown to agree with theoretical models. Formation of columnar structures accompanied the oxygen RIE of CVD diamond films and cubo-octahedral crystallites. Using scanning electron microscopy (SEM) and AFM the preferential formation of columnar structures in the inter-granular area of the diamond films has been detected. Surface contamination by silicon oxide has been identified by EDAX on the diamond surface and specifically on the columnar structures. Analysis by XPS demonstrated that the RIE etched surfaces were oxygen terminated and also were partially graphitised. A discussion on the mechanism of columnar formation has been presented. From the thermal oxidation of cubo-octahedral CVD diamond crystallites the activation energies and pre-exponential factors of the {100} and {111} diamond surfaces were measured, using optical profilometry, to be 221 ± 34 kJ mol-1, 2.3 x 109 nm s-1 Pa-1 and 286 ± 29 kJ mol-1, 1.9 x 1014 nm s-1 Pa-1 over the temperature range 535oC to 600oC respectively. Thermal oxidation of {100} and {111} diamond surfaces was accompanied with the formation of etch pits, increase of surface roughness and the exposure of {113} diamond surfaces between the {100} and {111} surfaces. A mechanism for the thermal oxidation of the diamond surfaces has been proposed

NASA SBIR abstracts of 1990 phase 1 projects

The research objectives of the 280 projects placed under contract in the National Aeronautics and Space Administration (NASA) 1990 Small Business Innovation Research (SBIR) Phase 1 program are described. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses in response to NASA's 1990 SBIR Phase 1 Program Solicitation. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 280, in order of its appearance in the body of the report. The document also includes Appendixes to provide additional information about the SBIR program and permit cross-reference in the 1990 Phase 1 projects by company name, location by state, principal investigator, NASA field center responsible for management of each project, and NASA contract number