801 resultados para Plastic morphology
Resumo:
The goal of this thesis was to make a dimensioning tool to determine the plastic capacity of the boiler supporting header. The capacity of the header is traditionally determined by using FE-method during the project phase. By using the dimensioning tool the goal is to ensure the capacity already in the proposal phase. The study began by analyzing the headers of the ongoing projects by using FE-method. For the analytical solution a plain header was analyzed without the effects of branches or lug. The calibration of parameters in the analytical solution was made using these results. In the analytical solution the plastic capacity of the plastic hinges in the header was defined. The stresses caused by the internal pressure as well as the normal and shear forces caused by the external loading reduced the plastic moment. The final capacity was determined by using the principle of virtual work. The weakening effect of the branches was taken into account by using pressure areas. Also the capacity of the punching shear was defined. The results from the FE-analyses and the analytical solution correlate with each other. The results from the analytical solution are conservative but give correct enough results when considering the accuracy of the used method.
Resumo:
The paper industry is constantly looking for new ideas for improving paper products while competition and raw material prices are increasing. Many paper products are pigment coated. Coating layer is the top layer of paper, thus by modifying coating pigment also the paper itself can be altered and value added to the final product. In this thesis, synthesis of new plastic and hybrid pigments and their performance in paper and paperboard coating is reported. Two types of plastic pigments were studied: core-shell latexes and solid beads of maleimide copolymers. Core-shell latexes with partially crosslinked hydrophilic polymer core of poly(n-butyl acrylate-co-methacrylic acid) and a hard hydrophobic polystyrene shell were prepared to improve the optical properties of coated paper. In addition, the effect of different crosslinkers was analyzed and the best overall performance was achieved by the use of ethylene glycol dimethacrylate (EGDMA). Furthermore, the possibility to modify core-shell latex was investigated by introducing a new polymerizable optical brightening agent, 1-[(4-vinylphenoxy)methyl]-4-(2-henylethylenyl)benzene which gave promising results. The prepared core-shell latex pigments performed smoothly also in pilot coating and printing trials. The results demonstrated that by optimizing polymer composition, the optical and surface properties of coated paper can be significantly enhanced. The optimal reaction conditions were established for thermal imidization of poly(styrene-co-maleimide) (SMI) and poly(octadecene-co-maleimide) (OMI) from respective maleic anhydride copolymer precursors and ammonia in a solvent free process. The obtained aqueous dispersions of nanoparticle copolymers exhibited glass transition temperatures (Tg) between 140-170ºC and particle sizes from 50-230 nm. Furthermore, the maleimide copolymers were evaluated in paperboard coating as additional pigments. The maleimide copolymer nanoparticles were partly imbedded into the porous coating structure and therefore the full potential of optical property enhancement for paperboard was not achieved by this method. The possibility to modify maleimide copolymers was also studied. Modifications were carried out via N-substitution by replacing part of the ammonia in the imidization reaction with amines, such as triacetonediamine (TAD), aspartic acid (ASP) and fluorinated amines (2,2,2- trifluoroethylamine, TFEA and 2,2,3,3,4,4,4-heptafluorobuthylamine, HFBA). The obtained functional nanoparticles varied in size between 50-217 nm and their Tg from 150-180ºC. During the coating process the produced plastic pigments exhibited good runnability. No significant improvements were achieved in light stability with TAD modified copolymers whereas nanoparticles modified with aspartic acid and those containing fluorinated groups showed the desired changes in surface properties of the coated paperboard. Finally, reports on preliminary studies with organic-inorganic hybrids are presented. The hybrids prepared by an in situ polymerization reaction consisted of 30 wt% poly(styrene- co-maleimide) (SMI) and high levels of 70 wt% inorganic components of kaolin and/or alumina trihydrate. Scanning Electron Microscopy (SEM) images and characterization by Fourier Transform Infrared Spcetroscopy (FTIR) and X-Ray Diffraction (XRD) revealed that the hybrids had conventional composite structure and inorganic components were covered with precipitated SMI nanoparticles attached to the surface via hydrogen bonding. In paper coating, the hybrids had a beneficial effect on increasing gloss levels.
Resumo:
ABSTRACT The species of the genus Byrsonima Rich. ex Kunth are of great medicinal and economic importance, but they are still poorly studied with respect to their propagules. This study describes, illustrates and comparse morphological aspects of the pyrenes of Byrsonima crassifolia (L.) Kunth, Byrsonima verbascifolia (L.) DC. and Byrsonima coccolobifolia Kunth occurring in areas of savannah of Boa Vista, Roraima. The pyrenes are globoid, obovoid to ovoid, with endocarp dark brown in color, with a corrugated and reticulate surface and corneous consistency. They possess distinctly septate locules with or without seeds, the outer wall of which are dark brown in color with corneous consistency and thin black inner walls also with corneous consistency. The number of locules and seeds per pyrene among the species varies. The seeds are exalbuminous, globoid, obovoid to ovoid, with a thin, smooth integument and are light-brown in color. They have radicular lobes and hypostasis. The embryo is continuous and axial with cylindrical spirally rolled cotyledons. The diameter of pyrenes of Byrsonima crassifolia is greater than in the other two species. The pyrenes of B. coccolobifolia are longer and heavier, while those of B. verbascifolia are lighter and the seeds have greater lengths, widths and thickness compared to the other two species studied. The three species have similar morphologies, differing in the size and weight of pyrenes and seeds.
Resumo:
ABSTRACT The objectives of this study were to morphologically characterize fruits of the babassu palm tree (Attalea vitrivir) and to estimate their productivity in the north of Minas Gerais State, Brazil. Twenty mature fruits were collected from 10 plants in three different areas in Januária, Minas Gerais. Eighteen biometric parameters of the fruits were measured, the oil contents of the seeds was determined, the adherence to normal distribution was evaluated, distribution frequencies were evaluated and the effects of individuals and areas on the variables and the correlations between them were analyzed. The production of fruit bunches per plant and the number of fruits per bunch from 10 plants were quantified in three areas and the potential production under both natural harvesting and cultivation conditions were estimated. Significant differences were found among all of the biometric parameters examined between the different individuals and the different areas, which shows wide morphological variability in the fruits. The average oil content was 45.7%, but with significant differences among individuals. The observed variability favors the selection of productive individuals in genetic improvement programs. The potential productivity of endocarps and oil based on a density of 400/plants per hectare would be respectively 6.4 and 1.2 tons/ha, which indicates the possibility of using A. vitrivir for producing charcoal, bio fuels, and for carbon fixation.
Resumo:
OBJECTIVE: To evaluate the relation of medical research, with the participation of prominent plastic surgeon in Congress.METHODS: We reviewed the scientific programs of the last 3 Brazilian Congress of Surgery, were selected 21 Brazilian plástic surgeons invited to serve as panelists or speakers in roundtable sessions in the last 3 congresses (Group 1). We randomly selected and paired by other members (associates) of the Brazilian Society of Plastic Surgery, with no participation in congress as speaker (Group 2). We conducted a search for articles published in journals indexed in Medline, Lilacs and SciELO for all doctors selected during the entire academic career and the last 5 years from March 2007 until March 2012. We assessed the research activity through the simple counting of the number of publications in indexed journals for each professional. The number of publications groups was compared.RESULTS: articles produced throughout career: Group 1- 639 articles (average of 30.42 items each). Group 2- 79 articles (mean 3.95 articles each). Difference between medias: p <0.001.CONCLUSION: The results demonstrate that the Brazilian Society of Plastic Surgery seeking professionals with a greater number of publications and journals of higher impact. This approach encourages new members to pursue a higher qualification, and give security to congressmen, they can rely on the existence of a technical criterion in the choice of speakers.
Resumo:
Objective: to discuss the participation of Plastic Surgery in the reconstruction of the chest wall, highlighting relevant aspects of interdisciplinaryness. Methods: we analyzed charts from 20 patients who underwent extensive resection of the thoracic integument, between 2000 and 2014, recording the indication of resection, the extent and depth of the raw areas, types of reconstructions performed and complications. Results: among the 20 patients, averaging 55 years old, five were males and 15 females. They resections were: one squamous cell carcinoma, two basal cell carcinomas, five chondrosarcomas and 12 breast tumors. The extent of the bloody areas ranged from 4x9 cm to 25x40 cm. In 12 patients the resection included the muscular plane. In the remaining eight, the tumor removal achieved a total wall thickness. For reconstruction we used: one muscular flap associated with skin grafting, nine flaps and ten regional fasciocutaneous flaps. Two patients undergoing reconstruction with fasciocutaneous flaps had partially suffering of the flap, solved with employment of a myocutaneous flap. The other patients displayed no complications with the techniques used, requiring only one surgery. Conclusion: the proper assessment of local tissues and flaps available for reconstruction, in addition to the successful integration of Plastic Surgery with the specialties involved in the treatment, enable extensive resections of the chest wall and reconstructions that provide patient recovery.
Resumo:
PURPOSE: In placentas from uncomplicated pregnancies, Hofbauer cells either disappear or become scanty after the fourth to fifth month of gestation. Immunohistochemistry though, reveals that a high percentage of stromal cells belong to Hofbauer cells. The aim of this study was to investigate the changes in morphology and density of Hofbauer cells in placentas from normal and pathological pregnancies. METHODS: Seventy placentas were examined: 16 specimens from normal term pregnancies, 10 from first trimester's miscarriages, 26 from cases diagnosed with chromosomal abnormality of the fetus, and placental tissue specimens complicated with intrauterine growth restriction (eight) or gestational diabetes mellitus (10). A histological study of hematoxylin-eosin (HE) sections was performed and immunohistochemical study was performed using the markers: CD 68, Lysozyme, A1 Antichymotrypsine, CK-7, vimentin, and Ki-67. RESULTS: In normal term pregnancies, HE study revealed Hofbauer cells in 37.5% of cases while immunohistochemistry revealed in 87.5% of cases. In first trimester's miscarriages and in cases with prenatal diagnosis of fetal chromosomal abnormalities, both basic and immunohistochemical study were positive for Hofbauer cells. In pregnancies complicated with intrauterine growth restriction or gestational diabetes mellitus, a positive immunoreaction was observed in 100 and 70% of cases, respectively. CONCLUSIONS: Hofbauer cells are present in placental villi during pregnancy, but with progressively reducing density. The most specific marker for their detection seems to be A1 Antichymotrypsine. It is remarkable that no mitotic activity of Hofbauer cells was noticed in our study, as the marker of cellular multiplication Ki-67 was negative in all examined specimens.
Resumo:
Two types of probiotics were used in piglets. One product is a mixed culture of viable Lactobacillus acidophilus, Enterococcus faecium e Bifidobacterium bifidum. The second product is composed of inactivated Lactobacillus acidophilus cells. The piglets received two weekly oral doses for 30 days while a control group did not receive probiotics. All piglets were euthanized at the 30th day of life and the mesenteric lymph nodes, the small intestine, and blood samples were collected. The tissue samples were studied by light microscopy and the blood serum was analyzed by ELISA method. The treatment with the probiotic with viable cells produced higher serum levels of IgA (P<0.05) and more IgA expressing cells were found in the mesenteric lymph nodes than observed in the inactivated cells treatment or control groups (P<0.05). Also, intestinal villi were longer, crypts were deeper (P<0.05) and fecal coliform count was lower than found in the inactivated product (P<0.05). These results suggest that viable probiotics are more efficient than inactivated probiotics to induce immunostimulation and intestinal modifications in piglets, thus improving their health and development.
Resumo:
The morphology of the accessory genital glands of the male agouti was studied in twenty-three animals that were raised in captivity. Twenty animals had their genital glands dissected in situ for macroscopic description. The samples of each gland were recovered, embedded in paraffin, sliced and stained by Hematoxylin-Eosin technique. It was founded four pairs of glands: the vesicular glands, the coagulating glands, the prostate and the bulbourethral glands. Histological characteristics of the vesicular, coagulating and prostate glands showed similar morphology, within the pseudostratified columnar epithelium. The tubulo-alveolar type of the bulbourethral glands showed a lack of connective tissue among the tubules, a small amount of red stained presented it the cytoplasm, and the presence of vacuoles in the tissue. This study concluded that the agouti showed to have similar morphological aspect described in the others species of rodents.
Resumo:
The aim of this study was to describe the topography of the spinal cord of the red-footed tortoise to establish a morphological basis for applied research in anesthesiology and morphology. Six tortoises from the state of Maranhão (Brazil) that had died of natural causes were used. The common carotid artery was used to perfuse the arterial system with saline solution (heated to 37ºC) and to fix the material with a 20% formaldehyde solution. The specimens were then placed in a modified decalcifying solution for 72 hours to allow dorsal opening of the carapace with a chisel and an orthopedic hammer. Dissection of the dorsal musculature and sectioning of the vertebral arches were performed to access the spinal cord. The results revealed the spinal cord of G. carbonaria to be an elongated, whitish mass that reached the articulation between the penultimate and last caudal vertebrae. The cervical intumescence (Intumescentia cervicalis) was located between vertebral segments C5 and T1, whereas the lumbosacral intumescence (Intumescentia lumbalis) was located between T6 and Ca1.
Resumo:
Primate order includes around 180 species. Morphological aspects of New World non-human primates (NHP) have been extensively investigated since last century. General commonsense describes oral cavity adaptations according to diet and feeding, dentition, tongue projection and head shape. Morphological appearance and dimension of the hard palate have been outstanding as interest in many species including man. Six young Saimiri sciureus hard palate were investigated. We measured the hard palate distance (HL), intercanine distance (ICD), intermolar distance (IMD), and interpremolar distance (IPD). Complete and incomplete palatine crests were quantified. We believe that better understanding of the mouth roof morphology will contribute to improve the management of captive animal's diet in order to re-introduce the animals in its habitat.
Resumo:
The rhea (Rhea americana americana) is an american bird belonging to Ratite's family. Studies related to its morphology are still scarce. This study aims to describe the macroscopic structures of the oropharyngeal cavity. Five heads (2 to 6 months old) formalin preserved were anatomically dissected to expose the oropharynx. The oropharynx of the rhea was "bell-shaped" composed by the maxillary and mandibular rhamphotheca. The roof and floor presented two distinct regions different in colour of the mucosa. The rostral region was pale pink contrasting to grey coloured caudal region. The median longitudinal ridge extended rostrally from the apex of the choana to the tip of the beak in the roof and it is clearly more prominent and rigid than the homolog in the floor that appeared thin and stretched merely along the rostral portion of the regio interramalis. The floor was formed by the interramal region, (regio interramalis) tongue and laryngeal mound containing glove-shaped glottis. This study confirmed the basic morphology of the oropharinx of the rhea. However, important morphological information not previously described is highlighted and contradictory information present in the literature is clarified.