Vibrations in Rotating Machinery Arising from Minor Imperfections in Component Geometries

Vibrations in machines can cause noise, decrease the performance, or even damage the machine. Vibrations appear if there is a source of vibration that excites the system. In the worst case scenario, the excitation frequency coincides with the natural frequency of the machine causing resonance. Rotating machines are a machine type, where the excitation arises from the machine itself. The excitation originates from the mass imbalance in the rotating shaft, which always exists in machines that are manufactured using conventional methods. The excitation has a frequency that is dependent on the rotational speed of the machine. The rotating machines in industrial use are usually designed to rotate at a constant rotational speed, the case where the resonances can be easily avoided. However, the machines that have a varying operational speed are more problematic due to a wider range of frequencies that have to be avoided. Vibrations, which frequencies equal to rotational speed frequency of the machine are widely studied and considered in the typical machine design process. This study concentrates on vibrations, which arise from the excitations having frequencies that are multiples of the rotational speed frequency. These vibrations take place when there are two or more excitation components in a revolution of a rotating shaft. The dissertation introduces four studies where three kinds of machines are experiencing vibrations caused by different excitations. The first studied case is a directly driven permanent magnet generator used in a wind power plant. The electromagnetic properties of the generator cause harmonic excitations in the system. The dynamic responses of the generator are studied using the multibody dynamics formulation. In another study, the finite element method is used to study the vibrations of a magnetic gear due to excitations, which frequencies equal to the rotational speed frequency. The objective is to study the effects of manufacturing and assembling inaccuracies. Particularly, the eccentricity of the rotating part with respect to non-rotating part is studied since the eccentric operation causes a force component in the direction of the shortest air gap. The third machine type is a tube roll of a paper machine, which is studied while the tube roll is supported using two different structures. These cases are studied using different formulations. In the first case, the tube roll is supported by spherical roller bearings, which have some wavinesses on the rolling surfaces. Wavinesses cause excitations to the tube roll, which starts to resonate at the frequency that is a half of the first natural frequency. The frequency is in the range where the machine normally operates. The tube roll is modeled using the finite element method and the bearings are modeled as nonlinear forces between the tube roll and the pedestals. In the second case studied, the tube roll is supported by freely rotating discs, which wavinesses are also measured. The above described phenomenon is captured as well in this case, but the simulation methodology is based on the flexible multibody dynamics formulation. The simulation models that are used in both of the last two cases studied are verified by measuring the actual devices and comparing the simulated and measured results. The results show good agreement.

The hemolytic component of cancer anemia: effects of osmotic and metabolic stress on the erythrocytes of rats bearing multifocal inoculations of the Walker 256 tumor

Cancer anemia is classified as an anemia of chronic diseases, although it is sometimes the first symptom of cancer. Cancer anemia includes a hemolytic component, important in the terminal stage when even transfused cells are rapidly destroyed. The presence of a chronic component and the terminal complications of the illness limit studies of the hemolytic component. A multifocal model of tumor growth was used here to simulate the terminal metastatic dissemination stage (several simultaneous inoculations of Walker 256 cells). The hemolytic component of anemia began 3-4 days after inoculation in 100% of the rats and progressed rapidly thereafter: Hb levels dropped from 14.9 ± 0.02 to 8.7 ± 0.06 from days 7 to 11 (~5 times the physiologically normal rate in rats) in the absence of bleeding. The development of anemia was correlated (r2 = 0.86) with the development of other systemic effects such as anorexia. There was a significant decrease in the osmotic fragility of circulating erythrocytes: the NaCl concentration causing 50% lysis was reduced from 4.52 ± 0.06 to 4.10 ± 0.01 (P<0.01) on day 7, indicating a reduction in erythrocyte volume. However, with mild metabolic stress (4-h incubation at 37oC), the erythrocytes showed a greater increase in osmotic fragility than the controls, suggesting marked alteration of erythrocyte homeostasis. These effects may be due to primary plasma membrane alterations (transport and/or permeability) and/or may be secondary to metabolic changes. This multifocal model is adequate for studying the hemolytic component of cancer anemia since it is rapid, highly reproducible and causes minimal animal suffering.

Production and characterization of a monoclonal antibody against an Ascaris suum allergenic component

Ascaris suum allergenic components (PIII) separated by gel filtration chromatography of an adult worm extract were used to immunize BALB/c mice. Popliteal lymph node cells taken from the immunized animals were fused with SP2/O myeloma cells using polyethylene glycol (MW 1450) as fusogen. The hybridomas were cultured in HAT-containing medium and cloned at limiting dilutions. Supernatants from the growing hybrids were screened by ELISA using plates coated with PIII or the A. suum crude extract. The monoclonal antibody obtained, named MAC-3 (mouse anti-A. suum allergenic component), is an IgG1 kappa mouse immunoglobulin that specifically recognizes a 29,000 molecular weight protein (called allergenic protein) with an affinity constant of 1.7 x 10(9) M-1. The A. suum components recognized by MAC-3 induce specific IgE antibody production in immunized BALB/c mice. Ascitic fluid induced in Swiss mice by injecting ip the hybridoma cells and incomplete Freund's adjuvant was purified by affinity chromatography using a protein A-Sepharose column. The purified monoclonal antibody was then coupled to activated Sepharose beads in order to isolate the A. suum allergenic component from the whole extract by affinity chromatography.

Identification and characterization of the two-component NtrY/NtrX regulatory system in Azospirillum brasilense

Two Azospirillum brasilense open reading frames (ORFs) exhibited homology with the two-component NtrY/NtrX regulatory system from Azorhizobium caulinodans. These A. brasilense ORFs, located downstream to the nifR3ntrBC operon, were isolated, sequenced and characterized. The present study suggests that ORF1 and ORF2 correspond to the A. brasilense ntrY and ntrX genes, respectively. The amino acid sequences of A. brasilense NtrY and NtrX proteins showed high similarity to sensor/kinase and regulatory proteins, respectively. Analysis of lacZ transcriptional fusions by the ß-galactosidase assay in Escherichia coli ntrC mutants showed that the NtrY/NtrX proteins failed to activate transcription of the nifA promoter of A. brasilense. The ntrYX operon complemented a nifR3ntrBC deletion mutant of A. brasilense for nitrate-dependent growth, suggesting a possible cross-talk between the NtrY/X and NtrB/C sensor/regulator pairs. Our data support the existence of another two-component regulatory system in A. brasilense, the NtrY/NtrX system, probably involved in the regulation of nitrate assimilation.

Fuzzy tolerance/equivalence relations from intersection, union and complement operators and their application to a clustering method

This master thesis work introduces the fuzzy tolerance/equivalence relation and its application in cluster analysis. The work presents about the construction of fuzzy equivalence relations using increasing generators. Here, we investigate and research on the role of increasing generators for the creation of intersection, union and complement operators. The objective is to develop different varieties of fuzzy tolerance/equivalence relations using different varieties of increasing generators. At last, we perform a comparative study with these developed varieties of fuzzy tolerance/equivalence relations in their application to a clustering method.

APOA1/C3/A4 gene cluster variability and lipid levels in Brazilian children

Genetic studies have suggested that polymorphisms of genes coding for apolipoproteins are significant determinants of serum lipoprotein and lipid levels in adults. However, only a few studies have investigated the association of these polymorphisms in children. Therefore, in the present investigation we studied the distribution of APOA1 -75 G>A, +83 C>T, APOC3 -482 C>T, -455 T>C and 3238 C>G, and APOA4 Q360H and T347S polymorphisms and their influence on plasma lipoprotein levels in children from a Brazilian northeastern admixed population. The seven polymorphic sites were genotyped in 414 children aged 5 to 15 years (mean 8.9 ± 2.9). The genotypes of the seven polymorphic sites were assessed by PCR-RFLP methods. The frequencies of the less common alleles were, in general, intermediate among parental populations, as expected. Strong linkage disequilibrium was detected between polymorphisms at the APOA1, APOC3 and APOA4 loci in this admixed population sample. Overall the genotype effects seen in adults were weaker or absent in children. The APOC3/-455 and APOA4 T347S variants showed significant effects on HDL cholesterol in girls (P = 0.033 and P = 0.016, respectively). Significantly higher plasma total (P = 0.003) and LDL cholesterol (P = 0.004) levels were observed in boys who were carriers of the 3238G allele at the APOC3/3238 C>G site. These results disclosed an overall absence of associations between these polymorphisms and lipids in children. This finding is not unexpected because expression of the effect of these polymorphisms might depend on the interaction with environmental variables both internal and external to the individual.

Genetic potential for an acute inflammatory response in IgA glomerulonephritis in mice

Mice selected on the basis of an acute inflammatory response (AIR) can provide information about the immunopathological mechanisms of glomerulonephritis. We studied the differences between mice selected for a maximal AIR (AIRmax that attract more polymorphonuclear cells to the site of injury) or a minimal AIR (AIRmin that attract more mononuclear cells) in an experimental model of IgA nephropathy in order to investigate the effect of genetic background on glomerular disease progression and the participation of the monocyte chemoattractant protein-1 (MCP-1) chemokine. IgA nephropathy was induced by intraperitoneal ovalbumin injection and bile duct ligation in AIRmax and AIRmin mice. Histological changes, urinary protein/creatinine ratio, serum IgA levels, immunofluorescence for IgA, IgG and complement C3 fraction, immunohistochemistry for macrophages and MCP-1, and MCP-1 levels in macerated kidney were determined. Mesangial IgA deposition was seen only in AIRmin mice, which presented more renal lesions. Increased serum IgA levels (1.5 ± 0.4 vs 0.3 ± 0.1 mg/mL, P < 0.001), high glomerular MCP-1 expression and decreased monocyte/macrophage infiltration in the interstitial area (0.3 ± 0.3 vs 1.1 ± 0.9 macrophages/field, P < 0.05) were detected in AIRmin mice compared to AIRmax mice. No glomerular monocyte/macrophage infiltration was detected in either strain. In spite of the absence of IgA deposition, AIRmax mice presented discrete or absent mesangial proliferation. The study showed that there are differences between mice selected for AIRmax and AIRmin with respect to serum IgA levels, histological damage and MCP-1 chemokine production after ovalbumin injection in combination with bile duct ligation.

EEG spike source localization before and after surgery for temporal lobe epilepsy: a BOLD EEG-fMRI and independent component analysis study

Simultaneous measurements of EEG-functional magnetic resonance imaging (fMRI) combine the high temporal resolution of EEG with the distinctive spatial resolution of fMRI. The purpose of this EEG-fMRI study was to search for hemodynamic responses (blood oxygen level-dependent - BOLD responses) associated with interictal activity in a case of right mesial temporal lobe epilepsy before and after a successful selective amygdalohippocampectomy. Therefore, the study found the epileptogenic source by this noninvasive imaging technique and compared the results after removing the atrophied hippocampus. Additionally, the present study investigated the effectiveness of two different ways of localizing epileptiform spike sources, i.e., BOLD contrast and independent component analysis dipole model, by comparing their respective outcomes to the resected epileptogenic region. Our findings suggested a right hippocampus induction of the large interictal activity in the left hemisphere. Although almost a quarter of the dipoles were found near the right hippocampus region, dipole modeling resulted in a widespread distribution, making EEG analysis too weak to precisely determine by itself the source localization even by a sophisticated method of analysis such as independent component analysis. On the other hand, the combined EEG-fMRI technique made it possible to highlight the epileptogenic foci quite efficiently.

Immune strategies using single-component LipL32 and multi-component recombinant LipL32-41-OmpL1 vaccines against leptospira

Genes encoding lipoproteins LipL32, LipL41 and the outer-membrane protein OmpL1 of leptospira were recombined and cloned into a pVAX1 plasmid. BALB/c mice were immunized with LipL32 and recombined LipL32-41-OmpL1 using DNA-DNA, DNA-protein and protein-protein strategies, respectively. Prime immunization was on day 1, boost immunizations were on day 11 and day 21. Sera were collected from each mouse on day 35 for antibody, cytokine detection and microscopic agglutination test while spleen cells were collected for splenocyte proliferation assay. All experimental groups (N = 10 mice per group) showed statistically significant increases in antigen-specific antibodies, in cytokines IL-4 and IL-10, as well as in the microscopic agglutination test and splenocyte proliferation compared with the pVAX1 control group. The groups receiving the recombined LipL32-41-OmpL1 vaccine induced anti-LipL41 and anti-OmpL1 antibodies and yielded better splenocyte proliferation values than the groups receiving LipL32. DNA prime and protein boost immune strategies stimulated more antibodies than a DNA-DNA immune strategy and yielded greater cytokine and splenocyte proliferation than a protein-protein immune strategy. It is clear from these results that recombination of protective antigen genes lipL32, lipL41, and ompL1 and a DNA-protein immune strategy resulted in better immune responses against leptospira than single-component, LipL32, or single DNA or protein immunization.

Effect of hyperoxia on the intestinal IgA secretory component in neonatal rats and on intestinal epithelial cells in vitro

Oxygen therapy is essential for the treatment of some neonatal critical care conditions but its extrapulmonary effects have not been adequately investigated. We therefore studied the effects of various oxygen concentrations on intestinal epithelial cell function. In order to assess the effects of hyperoxia on the intestinal immunological barrier, we studied two physiological changes in neonatal rats exposed to hyperoxia: the change in intestinal IgA secretory component (SC, an important component of SIgA) and changes in intestinal epithelial cells. Immunohistochemistry and Western blot were used to detect changes in the intestinal tissue SC of neonatal rats. To detect intestinal epithelial cell growth, cells were counted, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Giemsa staining were used to assess cell survival. Immunohistochemistry was used to determine SC expression. The expression of intestinal SC in neonatal rats under hyperoxic conditions was notably increased compared with rats inhaling room air (P < 0.01). In vitro, 40% O2 was beneficial for cell growth. However, 60% O2 and 90% O2 induced rapid cell death. Also, 40% O2 induced expression of SC by intestinal epithelial cells, whereas 60% O2did not; however, 90% O2 limited the ability of intestinal epithelial cells to express SC. In vivo and in vitro, moderate hyperoxia brought about increases in intestinal SC. This would be expected to bring about an increase in intestinal SIgA. High levels of SC and SIgA would serve to benefit hyperoxia-exposed individuals by helping to maintain optimal conditions in the intestinal tract.

Alternative complement pathway and factor B activities in rats with altered blood levels of thyroid hormone

Evaluating the activity of the complement system under conditions of altered thyroid hormone levels might help elucidate the role of complement in triggering autoimmune processes. Here, we investigated alternative pathway (AP) activity in male Wistar rats (180 ± 10 g) after altering their thyroid hormone levels by treatment with triiodothyronine (T3), propylthiouracil (PTU) or thyroidectomy. T3 and thyroxine (T4) levels were determined by chemiluminescence assays. Hemolytic assays were performed to evaluate the lytic activity of the AP. Factor B activity was evaluated using factor B-deficient serum. An anti-human factor B antibody was used to measure factor B levels in serum by radial immunodiffusion. T3 measurements in thyroidectomized animals or animals treated with PTU demonstrated a significant reduction in hormone levels compared to control. The results showed a reduction in AP lytic activity in rats treated with increasing amounts of T3 (1, 10, or 50 µg). Factor B activity was also decreased in the sera of hyperthyroid rats treated with 1 to 50 µg T3. Additionally, treating rats with 25 µg T3 significantly increased factor B levels in their sera (P < 0.01). In contrast, increased factor B concentration and activity (32%) were observed in hypothyroid rats. We conclude that alterations in thyroid hormone levels affect the activity of the AP and factor B, which may in turn affect the roles of AP and factor B in antibody production.

A comparison of two computer-assisted remedial reading programs for adolescent unskilled readers : component reading skills and repeated reading

This study compared the relative effectiveness of two computerized remedial reading programs in improving the reading word recognition, rate, and comprehension of adolescent readers demonstrating significant and longstanding reading difficulties. One of the programs involved was Autoskill Component Reading Subskills Program, which provides instruction in isolated letters, syllables, and words, to a point of rapid automatic responding. This program also incorporates reading disability subtypes in its approach. The second program, Read It Again. Sam, delivers a repeated reading strategy. The study also examined the feasibility of using peer tutors in association with these two programs. Grade 9 students at a secondary vocational school who satisfied specific criteria with respect to cognitive and reading ability participated. Eighteen students were randomly assigned to three matched groups, based on prior screening on a battery of reading achievement tests. Two I I groups received training with one of the computer programs; the third group acted as a control and received the remedial reading program offered within the regular classroom. The groups met daily with a trained tutor for approximately 35 minutes, and were required to accumulate twenty hours of instruction. At the conclusion of the program, the pretest battery was repeated. No significant differences were found in the treatment effects of the two computer groups. Each of the two treatment groups was able to effect significantly improved reading word recognition and rate, relative to the control group. Comprehension gains were modest. The treatment groups demonstrated a significant gain, relative to the control group, on one of the three comprehension measures; only trends toward a gain were noted on the remaining two measures. The tutoring partnership appeared to be a viable alternative for the teacher seeking to provide individualized computerized remedial programs for adolescent unskilled readers. Both programs took advantage of computer technology in providing individualized drill and practice, instant feedback, and ongoing recordkeeping. With limited cautions, each of these programs was considered effective and practical for use with adolescent unskilled readers.

Developmental variations in the peripheral erythrocytic system of the rainbow trout, Salmo gairdneri

The peripheral circulating erythrocytic system of the rainbow trout, l3 almo gairdner , was examined in vitro in relation differences in the morphology and multiple hemoglobin system organization of adult and juvenile red cells. Cells were separated by velocity sedimentation under unit gravity, a procedure requiring red cell exposure to an incubation medium for periods of at least three hours. Therefore , this must provide an environment in which red cells remain in a condition approximaing normalcy. Previous studies having demonstrated commonly employed media to be ineffective in this regard , a medium was developed through modification of Cortl and saline. One of the principal additions to this me dium , norepinephrine, altered cell regulation of intracellular calcium, magnesium and chloride concentrations. Catecholamine involvement was also suggeste d in the synthes is of hemoglobin . The procedure was found to separtate cells primarily by density and, to a lesser extent, by shape. Characterization of red cells revealed two subpopulations to exist . The first comprised the bulk of the cell population, and were of greater l ength, width, volume and major:minor axis ratio than the smaller population; these were adult cells. The later, juvenile cells were of smaller overall size and were more spherical in shape . Juvenile cells also possessed fewer electrophore tpically distinguishable isomorphs than did adults with only eight of eleven hemoglobin component s typically found With maturation,hemoglobin complement with the development of three more bands. The total complement of the adult cell contained 7 cathodal bands and four anodal hemoglobin isomorphs. Bands acquired with maturation comprised the smallest percentage of the cells hemoglobin. each averaging less than one-percent of the total. Whether these additional bands are derived through degradation and reaggregation of existing components or are the product of pe gQy2 synthesis is not yet known.

A comparison of self-determined motivational experiences between participants and non-participants following the physical activity component of the CATCH Kid Club

The CATCH Kids Club (CKC) is an after-school intervention that has attempted to address the growing obesity and physical inactivity concerns publicized in current literature. Using Self-Determination Theory (SDT: Deci & Ryan, 1985) perspective, this study's main research objective was to assess, while controlling for gender and age, i f there were significant differences between the treatment (CKC program participants) and control (non- eKC) groups on their perceptions of need satisfaction, intrinsic motivation and optimal challenge after four months of participation and after eight months of participation. For this study, data were collected from 79 participants with a mean age of9.3, using the Situational Affective State Questionnaire (SASQ: Mandigo et aI., 2008). In order to determine the common factors present in the data, a principal component analysis was conducted. The analysis resulted in an appropriate three-factor solution, with 14 items loading onto the three factors identified as autonomy, competence and intrinsic motivation. Initially, a multiple analysis of co-variance (MANCOY A) was conducted and found no significant differences or effects (p> 0.05). To further assess the differences between groups, six analyses of co-variance (ANeOY As) were conducted, which also found no significant differences (p >0 .025). These findings suggest that the eKC program is able to maintain the se1fdetermined motivational experiences of its participants, and does not thwart need satisfaction or self-determined motivation through its programming. However, the literature suggests that the CKe program and other P A interventions could be further improved by fostering participants' self-determined motivational experiences, which can lead to the persistence of healthy PA behaviours (Kilpatrick, Hebert & Jacobsen, 2002).

A district school board's induction program for new administrators: a study of the effectiveness of the mentoring component

Please consult the paper edition of this thesis to read. It is available on the 5th Floor of the Library at Call Number: Z 9999 E38 K535 2008