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Articles de revues sur le sujet "Infiltrato"
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Laužikas, Giedrius, Gintaras Varanauskas et Juozas Stanaitis. « Apendikulinio infiltrato diagnostikos ir gydymo ypatumai ». Lietuvos chirurgija 2, no 1 (1 janvier 2004) : 0. http://dx.doi.org/10.15388/lietchirur.2004.1.2377.
Texte intégralRésumé :
Giedrius Laužikas, Gintaras Varanauskas, Juozas StanaitisVilniaus universiteto Bendrosios ir kraujagyslių chirurgijos klinikos Bendrosios chirurgijos centras,Vilniaus greitosios pagalbos universitetinė ligoninė,Šiltnamių g. 29, LT-2043 VilniusEl paštas: giedrius.lauzikas@vgpul.lt Įvadas / tikslas Apendikulinis infiltratas – viena iš ūminio apendicito formų, pasižyminti sudėtinga diagnostika ir gydymo ypatumais. Literatūroje diskutuojama, kuriam gydymo metodui – operaciniam ar konservatyviam – teikti pirmenybę. Mūsų darbo tikslas – apžvelgti apendikulinių infiltratų diagnostikos ir gydymo ypatumus pagal literatūros ir VGPUL duomenis. Ligoniai ir metodai Retrospektyviai išnagrinėtos 49 ligonių, 1992–2002 m. gydytų Vilniaus greitosios pagalbos universitetinėje ligoninėje nuo apendikulinio infiltrato, ligos istorijos. Vėlyvieji gydymo rezultatai vertinti apklausiant telefonu ar peržiūrint kartotinės hospitalizacijos ligos istorijas. Rezultatai Per 1992–2002 m. VGPUL Bendrosios chirurgijos klinikoje nuo apendikulinio infiltrato gydyti 49 ligoniai: 27 moterys ir 22 vyrai. Į stacionarą šia liga sergantys ligoniai kreipėsi vidutiniškai po 8,4 paros nuo ligos pradžios. Iki tol 43 ligoniai gydėsi patys, 4 – gydyti poliklinikoje nuo kitų ligų, 2 – išleisti iš ligoninės priimamojo. Stacionare vidutiniškai praleido po 17,4 dienos, dauguma jų pasveiko, mirė 2 ligoniai (4,08%). Diagnozuojant apendikulinį infiltratą remtasi šiais medicininės apžiūros duomenimis: čiuopiamu infiltratu dešinėje klubinėje srityje (29 ligoniai; 59,2%), pilvo echoskopijos (35 ligoniai; 71,4%) ar KT metu (vienas ligonis) matomu dariniu dešinėje klubinėje srityje. Keturiasdešimt apendikuliniu infiltratu sirgusių ligonių buvo operuoti: 27 ligoniams – atlikta laparotomija dešinėje klubinėje srityje ir drenavimas, 6 – vidurinė laparotomija ir drenavimas, 6 – ileocekalinio kampo rezekcija, 1 – dešinioji hemikolektomija. Devyni ligoniai buvo gydyti konservatyviai. Vėlyvuoju laikotarpiu iš 24 ligonių 18 buvo operuoti: šešiolikai atlikta apendektomija, dviem – dešinioji hemikolektomija. Šešiems iš 49 (12,24%) šia liga sirgusių ligonių diagnozuota onkologinė liga. Išvados Gydant apendikulinį infiltratą reikėtų skirti konservatyvų gydymą ir pagal galimybes išsiaiškinti ligos priežastį. Jei šis gydymas neveiksmingas, rekomenduojama ligonį operuoti. Operacijos metu radus apendikulinį infiltratą, tikslinga atlikti radikalią rezekcinę operaciją pagal onkologinius principus. Prasminiai žodžiai: apendikulinis infiltratas, laparotomija, drenavimas, ileocekalinio kampo rezekcija, hemikolektomija Diagnostics and treatment of appendiceal mass: 10 years of experience at Vilnius University Emergency Hospital Giedrius Laužikas, Gintaras Varanauskas, Juozas Stanaitis Background / Objective Discussions still continue concerning treatment tactics for appendiceal mass. The main endpoint of the study was to analyse appendiceal mass diagnostic measurements and treatment at Vilnius Emergency University Hospital. Patients and methods Medical records for patients admitted with "appendiceal mass" between 1992–2002 were reviewed. There were 49 patients treated for appendiceal mass at Vilnius Emergency University Hospital General Surgery Clinic during 1992–2002: 27 women, 22 men. Results The mean duration of hospitalisation was 17.4 days, two patients (4.08%) died. "Appendiceal mass" was diagnosed by clinical investigation in 29 patients (59.2%), by sonoscopy in 35 patients (71.43%), and by CT-scan in one patient. Fourty patients were operated on. Laparotomy in right iliac fossa and drainage were performed in 27, median laparotomy and drainage in six, ileocecal resection in 6 cases, right hemicolectomy in one case. Nine patients received conservative treatment. Malignancy was diagnosed in 6 patients (12.24%). Most "appendiceal masses" should be treated conservatively and examined carefully. Conclusions If there is no effect of conservative treatment, an operation should be performed. If appendiceal mass is found during operation, a radical resection according to oncological principles is the operation of choice. Keywords: appendiceal mass, laparotomy, drainage, ileocecal resection, hemicolectomy
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Briscoe, D. M., J. S. Pober, W. E. Harmon et R. S. Cotran. « Expression of vascular cell adhesion molecule-1 in human renal allografts. » Journal of the American Society of Nephrology 3, no 5 (novembre 1992) : 1180–85. http://dx.doi.org/10.1681/asn.v351180.
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The expression of vascular cell adhesion molecule-1 (VCAM-1) in 11 human renal allograft biopsies and 3 normal kidney specimens was investigated by immunocytochemistry. VCAM-1 expression was correlated with the degree of CD3+ T cell infiltration and the clinicopathologic diagnosis of acute rejection. CD3+ infiltrates were seen in all biopsies with rejection, but not in normal biopsies or one with acute tubular necrosis, and were accompanied by CD68+ monocyte/macrophage infiltrates. In normal biopsies, VCAM-1 was present on occasional tubules, where its expression was patchy and restricted to the basolateral surface of cells with slight cytoplasmic staining. The total number of tubules expressing VCAM-1 significantly increased in specimens infiltrated with CD3+ T cells. Moreover, in these infiltrated biopsy specimens, VCAM-1 was present throughout the cytoplasm of tubular cells concentrated on the basolateral surface. VCAM-1 was also observed on vascular endothelial cells where its expression correlated with the degree of CD3+ infiltrate. Mean scores (0 to 3+) for endothelial VCAM-1 expression increased from 0 (CD3+ score, 0) to a mean score of 2.25 in association with CD3+ T cell infiltrates (CD3+ score, 3). Endothelial VCAM-1 was predominantly on vessels in areas of infiltrate, including peritubular capillaries, venules, and arterioles, but was notably absent on glomerular endothelium. VCAM-1 also stained mesangial cells in an occasional CD3+ infiltrated specimen. It was concluded that the expression of VCAM-1 is increased on renal tubules and renovascular endothelium in rejecting renal allografts in association with CD3+ infiltrates.(ABSTRACT TRUNCATED AT 250 WORDS)
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Yu, Peng, Ma Qian et Graham B. Schaffer. « Rapid Prototyping of Aluminium Alloy Parts : The Effect of Infiltration Atmosphere ». Materials Science Forum 618-619 (avril 2009) : 635–40. http://dx.doi.org/10.4028/www.scientific.net/msf.618-619.635.
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An investigation has been made on the infiltration behaviour in rapid prototyping of Al alloy parts under different infiltration atmospheres. An Al 6061 alloy preform was first prepared by selective laser sintering. Then the aluminium precursor powders in the preform were converted into AlN to form a skeletal AlN structure, which was subsequently pressureless infiltrated with a molten Al 6061 alloy under nitrogen, argon or vacuum. The pathway of the infiltrant was determined by density measurements in conjunction with metallographic examination and quantitative image analysis. Detailed comparison of the microstructures at the surface and the centre of the as-infiltrated samples indicates that the pathway into the porous preform is dependent on the infiltration atmosphere. Under vacuum, the infiltrant fills the interior of the preform first and then propagates to the surface. In contrast, under nitrogen or argon, the infiltrant penetrates along the surface prior to filling the interior.
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Chimanski, Afonso, Amanda Martins Jordão, Paulo Francisco Cesar et Humberto Naoyuki Yoshimura. « Devitrification in SiO2-B2O3-Al2O3-La2O3-TiO2 Glass during the Infiltration of Ceramic Composite ». Materials Science Forum 881 (novembre 2016) : 77–82. http://dx.doi.org/10.4028/www.scientific.net/msf.881.77.
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Dental prostheses made of ceramic composites infiltrated with glasses have been used due to their biocompatibility and possibility to mimic the natural teeth. In this study, the devitrification behavior of 20SiO2-25B2O3-25Al2O3-15La2O3-15TiO2 glass during the infiltration process in a porous alumina preform was investigated. Glass frits were prepared by melting the raw materials at 1500 °C for 60 min. The glass was infiltrated into the alumina preform at 1,150 or 1,200 °C for 60 min. The specimens were characterized by X-ray diffraction analysis and scanning electron microscopy. After the infiltration, it was possible to note that the devitrification process occurred in the remaining glass (excess glass that did not infiltrate in the preform), forming mostly aluminum borate and mullite crystalline phases. However, within the infiltrated composite no devitrification was noticed in the infiltrated glass. Possible explanations for this behavior are discussed.
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Thammarakcharoen, Faungchat, et Jintamai Suwanprateeb. « Preparation of 3DP Hydroxyapatite Composite by Single and Double Pass Poly(ε-caprolactone) Infiltration ». Key Engineering Materials 545 (mars 2013) : 69–73. http://dx.doi.org/10.4028/www.scientific.net/kem.545.69.
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Recently, porous hydroxyapatite was fabricated by three dimensional printing (3DP) in coupled with low temperature phosphorization to yield nanosized and low crystalline structure. However, brittleness was an intrinsic drawback for some foreseen applications. Polymer infiltration aiming to improve the toughness and mechanical integrity was thus carried out using biodegradable poly(ε-caprolactone) (PCL) as an infiltrant since it has shown good biocompatibility together with a high elongation and energy to failure as compared to other medical polymers. Three routes of infiltration were performed including melt infiltration of low molecular weight PCL (Mw ˜ 10,000), solution infiltration by 10 % high molecular weight PCL (Mw ˜ 80,000) and the combination of both melt and solution infiltration of low and high molecular weight PCL. The combination of low and high MW infiltration yielded the greatest increase in the mechanical properties and followed by the melt infiltration of low molecular weight PCL while the use of high MW infiltration yielded limited enhancement. After immersing in simulated body fluid (SBF), no significant changes in flexural properties were seen for both hydroxyapatite and high molecular weight infiltrated sample. However, flexural strength and strain at break of low molecular weight infiltrated sample largely dropped after 7 days of immersion to be closed to those of hydroxyapatite and high molecular weight infiltrated sample. The flexural properties of high-low infiltrated sample also decreased after immersion, but to a less degree and still maintained the greatest values amongst all samples. This could be associated to the difference in degradation of different molecular weight of PCL and the content of polymer infiltration induced by different infiltration routes. Calcium and phosphorus ions in the SBF were quantified and observed to be consumed continuously during immersion for all samples. Newly formed apatite crystals were observed to form on the surface of the infiltrated composites signifying that infiltration did not hinder the bioactivity of the composites.
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Prodan, Doina, Marioara Moldovan, Andrea Maria Chisnoiu, Codruța Saroși, Stanca Cuc, Miuța Filip, Georgiana Florentina Gheorghe et al. « Development of New Experimental Dental Enamel Resin Infiltrants—Synthesis and Characterization ». Materials 15, no 3 (21 janvier 2022) : 803. http://dx.doi.org/10.3390/ma15030803.
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The aim of the present study was to obtain experimental infiltration materials, intended for the treatment of dental white spots, and to investigate them. Two series of infiltrants (P1–P6)/(P1F–P6F) were obtained, based on different monomer mixtures, without/with glass filler (with fluoride release ability). Each infiltrant from the second series contained the same amount of glass powder, and each infiltrant from the (P–PF) group contained the same resin composition. The characteristics of the experimental infiltrants were investigated by degree of conversion (DC), mechanical strength, water sorption (WS), and fluoride release, in addition to residual monomer for (P1F–P6F) infiltrants. The results were compared with those obtained for commercial Icon infiltrant. For the experimental infiltrants, without/with filler, the recorded DC was in the range of 58.27–89.70%/60.62–89.99%, compared with Icon (46.94%) 24 h after polymerization. The release of fluoride depends on the permeability of the polymer matrix, with respect to the water sorption, which may help to diffuse ions in the storage medium but which can also influence the release of residual monomers. The highest flexural strengths were recorded for the (TEGDMA/HEMA/Bis-GMA) infiltrants (133.94 ± 16.389 MPa/146.31 ± 7.032 MPa). The best experimental infiltrants were P2 and P2F (Bis-GMA/HEMA/TEGDMA).
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Yang, Shao Feng, Wei Ping Chen, Meng Yan Han et De Zhi Zhu. « Microstructure and Interface Strength of MMCs Prepared by Pressureless Ni-Induced Infiltration Using Fe Alloy ». Applied Mechanics and Materials 37-38 (novembre 2010) : 652–57. http://dx.doi.org/10.4028/www.scientific.net/amm.37-38.652.
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Metal matrix composites (MMCs) were produced by Ni-induced pressureless infiltration using Fe alloy. The mainly fabrication process was that Ni and Al2O3 powders mixture was pressed and sintered after milled, and then the sintered Al2O3 ceramics were infiltrated by Fe alloy at 1600°C with 4h holding time. While the SEM and EPMA analyses indicated that the interface between ceramics and Fe alloy reaches a full homogeneity after infiltration and Fe alloy could infiltrate Al2O3 ceramic preforms and the maximum infiltration distance was more than 400 μm. This would increase the strength of interfacial due to excellent bonding interface. The fracture strength is about 63.0 MPa.
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Stasiak, Katarzyna, Robin Lindsay et Victor H. Engelhard. « Low immunogenicity of intracranial tumors limits immune response to brain malignancies ». Journal of Immunology 204, no 1_Supplement (1 mai 2020) : 242.51. http://dx.doi.org/10.4049/jimmunol.204.supp.242.51.
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Abstract The presence of CD8 T cells in tumors, including melanomas, is correlated with longer survival. Cutaneous melanoma is a highly immunogenic malignancy with high rate of dissemination into central nervous system but the brain is considered immunologically privileged due to the blood-brain barrier, which limits T cell entry. To determine if brain tumors are also poorly infiltrated by T cells we evaluated intracranial (IC) and subcutaneous (SC) B16 melanomas expressing different model antigens. CD8 T cells were present in IC tumors 7 days post tumor implantation in B16 melanomas expressing chicken ovalbumin (B16OVA) or influenza M1 protein (B16M1), but infiltrates were only 10% of those observed in SC tumors. We also observed that expression of homing receptor ligands (HRLs) known to mediate T cell infiltration was lower on IC than SC tumor-associated vasculature. Despite the fact that HRL expression decreased over time in tumors grown in both locations, T cell infiltrates increased, suggesting that HRL are not the only factor limiting T cells entry into IC tumors. To determine whether the IC tumor infiltrate size was limited by inefficient stimulation of effectors cells, we vaccinated mice to generate fully activated effector T cells able to recognize tumor associated antigen. Vaccination normalized the infiltrate sizes in IC and SC tumors. Interestingly, this was also dependent on expression of Ag by the tumor cells. This suggests that IC tumors are not able to efficiently elicit a robust immune response, possibly due to limitations on drainage to lymph nodes, while IC tumor vasculature does not impose inherently greater limitations on the ability of T cells to enter.
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Weil, Andrew C., Matt E. Kalaycio et James R. Cook. « Pulmonary Infiltration by CLL/SLL in the Presence of Inflammation : Significant or Incidental Finding?. » Blood 114, no 22 (20 novembre 2009) : 2352. http://dx.doi.org/10.1182/blood.v114.22.2352.2352.
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Abstract Abstract 2352 Poster Board II-329 Radiographically identified pulmonary infiltrates in patients with CLL are usually secondary to infectious causes. However, a subset of patients develop pathologic leukemic infiltrates. Lung biopsies containing both inflammation and CLL infiltrates are particularly problematic. It is unclear in such cases whether the CLL infiltrate represents a nonspecific “passenger effect” secondary to ongoing inflammation versus a pathologic leukemic infiltrate. Furthermore, it is unknown whether there are clinical factors that would help predict who is at higher risk for pulmonary infiltration by CLL. We retrospectively analyzed 45 transbronchial lung biopsies taken from 37 patients at the Cleveland Clinic between 1999 and 2008. We reviewed the biopsies for evidence of acute or chronic inflammation and involvment by CLL. Acute inflammation in our biopsies consisted of acute pneumonias. Cases displaying a lymphocytic infiltrate suspicious for CLL on routine H&E sections were further investigated by immunohistochemistry. The patients studied were 67.5% male with a median age of 67 (45-83) and a median absolute lymphocyte count of 2.75 (0.12 – 86.08). All patients at the time of diagnosis with CLL had flow cytometery of blood and/or bone marrow demonstrating CD5, CD19 positive B cells consistent with CLL. 72% of all patients were previously treated and 52% of patients had a RAI stage > 2 at the time of their diagnosis with CLL. CLL was identified in 20% of the biopsies. Of the 31.1% of biopsies showing acute inflammation, none had leukemia. CLL infiltration was found in association with and without chronic inflammation in 25% and 30.4% of the biopsies respectively. The median peripheral blood absolute lymphocyte count was 3.64 (1.33 – 86.08) in those with leukemic biopsies and 8.31 (0.12 – 79.12) in those without leukemic biopsies. Furthermore, only 33% of the patients with CLL positive biopsies had a RAI stage ≥ 3. At the time of biopsy, 7 previously treated patients were in remission; none of these cases displayed evidence of CLL in lung tissue. We found that the incidence of leukemic infiltration of lung biopsies did not increase in the presence of inflammation. In fact, the incidence of infiltration of biopsies with inflammation was lower than those without inflammation. These results demonstrate that leukemic infiltration on biopsies with inflammation is uncommon, and suggests that this phenomenon represents true, pathologic infiltration of the tissue by CLL and not a “passenger effect”. To the authors knowledge this is the largest study evaluating the association of inflammation and pathologic infiltration of pulmonary tissue by CLL. Disclosures: No relevant conflicts of interest to declare.
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Murphy, Christopher, Erjon Agushi, Zhangjie Su, Rainer Hinz, Federico Roncaroli et David Coope. « Quantitative Diffusion Tensor Imaging (DTI) Analysis Reveals Different Infiltrative Patterns of Oligodendrogliomas and Astrocytomas in Peri-Tumour White Matter ». Neurosurgery 84, no 5 (23 mars 2019) : E273. http://dx.doi.org/10.1093/neuros/nyz001.ni2.
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Abstract INTRODUCTION Gliomas are highly infiltrative primary brain tumours. Glioma infiltration is difficult to identify clinically using conventional diagnostic imaging. We used diffusion tensor imaging (DTI) to identify glioma infiltration in peritumour white matter (WM) and characterized differences between histological subtypes. METHODS We recruited 8 patients with a histological diagnosis of grade II or III glioma and 10 healthy controls. We compared fractional anisotropy (FA) maps of each patient against the control group using SPM8 (Matlab 2014a) to identify regions of glioma infiltration. The FA and mean diffusivity (MD) of formerly WM matter tumour regions, infiltrated WM and normal appearing WM were compared with a 2-sample t-test and characterized with respect to normal control data. RESULTS Our results have identified radiological evidence of infiltration in the peri-tumour WM of glioma patients. The infiltrated region of oligodendrogliomas extended further than that of astrocytomas. Oligodendrogliomas preferentially infiltrated larger WM tracts, whereas astrocytomas infiltrated more peripheral WM. In all grades, the 3 regions had significantly different diffusion parameters and there were significant differences between oligodendrogliomas and astrocytomas. CONCLUSION We identified previously unrecognized study wide significant changes in the peri-tumour WM of gliomas. Despite the known propensity of these tumours to infiltrate WM we found no significant DTI changes distant to the tumour. Our DTI results suggest oligodendrogliomas and astrocytomas demonstrate different infiltrative patterns, which highlights the need for astrocytomas and oligodendrogliomas to be studied separately.
Thèses sur le sujet "Infiltrato"
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Vettore, Marina. « The immunological landscape of primary brain tumors : a comparative study of the immunosuppressive myeloid cell populations in benign and malignant tumors ». Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3426697.
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The immune system plays a dual role in cancer progression, either preventing or promoting tumor progression and the fine regulation of the complex interaction between immune system and tumor determines patient outcome. It has been demonstrated that also in brain tumors a combination of signals and soluble factors secreted by tumor, immune and stromal cells are able to potentiate tumor progression. Therefore, the interest towards the characterization of tumor microenvironment in these tumors is growing and the presence of tumor infiltrating immune cells of myeloid origin has already been reported, but a clear phenotypic and functional characterization in human brain tumors still lacking. For this reason, in this research project we performed a deep analysis of both circulating and tumor-infiltrating leukocytes present in meningioma (MNG) and glioblastoma (GBM) patients in order to dissect their properties, with the ultimate goal of finding new immunological therapeutic strategies.
We thus performed an extensive immunophenotyping of peripheral blood and fresh tumor tissue at surgery by multiparametric flow cytometry in 34 patients affected by MNG (WHO grade I-II) and in 76 patients affected by GBM (WHO grade IV glioma), along with immunosuppressive activity of sorted cells of myeloid origin.
In the peripheral blood, we observed a number of significant alterations in myeloid cell subsets indicating a specific monocyte subsets as the main cell subset actively recruited to the tumor. Moreover, four subsets of myeloid-derived suppressor cells (MDSCs) are detectable in the blood and in the tumor tissue of patients affected by MNG and GBM. Three of these subsets are significantly expanded in the blood of patients, whereas two of them are significantly expanded in the tumor tissue.
In addition, we assayed ARG-1 (arginase 1) levels and activity in plasma samples from patients affected by MNG and GBM, and observed both a significantly increased level and a boost of its functional activity, compared to the control group.
At the tumor site, we observed a large leukocyte infiltrate, predominantly constituted by CD33+ myeloid cells, largely composed of macrophages endowed with suppressive activity and significantly expanded in both types of tumor. Based on the expression of different markers, in GBM patients, we were able to discriminate bone marrow-derived (BMDM) macrophages from resident microglia (MG). These populations showed a different suppressive activity, since BMDMs displayed a higher immunosuppressive activity compared to MG cells that showed low or no suppressive immune regulatory ability.
Taken together the results of this study shed light on the complex interaction between immune system and the main tumors of the brain.Il sistema immunitario svolge un duplice ruolo nella progressione del cancro, è in grado sia di prevenire che di promuovere la progressione tumorale e la regolazione della complessa interazione tra sistema immunitario ed il tumore è in grado di determinare la prognosi del paziente. Inoltre, è stato dimostrato che, anche nei tumori cerebrali, una combinazione di segnali e di fattori solubili secreti dal tumore, dalle cellule immunitarie e dalle cellule stromali, è in grado di potenziare la progressione tumorale. Pertanto, in questi tumori sta crescendo l'interesse verso la caratterizzazione del microambiente tumorale ed è già stata dimostrata la presenza di cellule immunitarie di origine mieloide infiltranti il tumore, ma una chiara caratterizzazione fenotipica e funzionale di queste popolazioni non è ancora stata documentata. Pertanto, in questo progetto di ricerca abbiamo eseguito un'analisi approfondita sia dei leucociti circolanti che dei leucociti infiltranti il tumore nei pazienti affetti da meningioma (MNG) e glioblastoma (GBM), al fine di studiarne le caratteristiche, con l'obiettivo finale di trovare nuove strategie terapeutiche. Abbiamo pertanto eseguito un’accurata immunofenotipizzazione del sangue periferico e del tessuto tumorale, analizzato subito dopo la resezione chirurgica, mediante citofluorimetria a flusso multi-parametrica in 34 pazienti con MNG (grado I-II OMS) e in 76 pazienti con GBM (glioma di grado IV OMS). Abbiamo inoltre testato l’attività immunosoppressiva delle popolazioni di origine mieloide isolate da biopsia. Nel sangue periferico abbiamo osservato delle alterazioni significative nelle sottopopolazioni di cellule di origine mieloide, rivelando che un particolare sottogruppo di monociti viene attivamente reclutato al sito tumorale. Inoltre, quattro sottopopolazioni di cellule soppressorie di derivazione mieloide (MDSC) sono rilevabili nel sangue e nel tessuto tumorale dei pazienti affetti da MNG e GBM. Tre di queste popolazioni sono significativamente espanse nel sangue dei pazienti, mentre due di esse sono significativamente espanse nel tessuto tumorale. In questo studio, abbiamo analizzato anche i livelli plasmatici di arginasi 1 (ARG-1) e la sua attività funzionale in campioni di plasma di pazienti con MNG o GBM ed abbiamo osservato sia un aumento significativo della sua concentrazione plasmatica che della sua attività funzionale, rispetto al gruppo di controllo. Analizzando il tessuto tumorale, abbiamo osservato la presenza di un importante infiltrato leucocitario, costituito prevalentemente da cellule mieloidi CD33+ ed in particolare da macrofagi dotati di attività soppressiva e la cui percentuale è notevolmente elevata in entrambi i tipi di tumore. Nei pazienti con GBM, sulla base dell'espressione di diversi marcatori, abbiamo potuto discriminare i macrofagi derivati dal midollo osseo (BMDM) dalla microglia (MG). Queste popolazioni macrofagiche hanno dimostrato avere una diversa attività soppressoria, infatti, i BMDM risultano essere più immunosoppressivi rispetto alla MG che invece ha una bassa o irrilevante capacità soppressoria. I risultati di questo studio sottolineano quindi l’esistenza di una complessa interazione tra sistema immunitario ed i principali tumori cerebrali.
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BARBAROSOS, Apostolos. « Valutazione dell'immunità antitumorale attraverso lo studio dell'infiltrato linfoplasmacellulare con anticorpi monoclonali e definizione di nuovi fattori prognostici nei pazienti affetti da cancro gastrico ». Doctoral thesis, La Sapienza, 2006. http://hdl.handle.net/11573/917479.
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Barrocu, Giovanni. « Le indagini sotto copertura ». Doctoral thesis, Università degli studi di Trieste, 2009. http://hdl.handle.net/10077/3077.
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2007/2008Il lavoro di stesura della tesi si è proposto, in particolare, di analizzare e approfondire la tematica dell’agente undercover – oggetto di copiosi studi nell’ambito sostanziale – sotto il meno esplorato profilo del suo inquadramento nelle dinamiche processuali, al fine di verificare la legittimità del ricorso al tale strumento, i limiti operativi dello stesso nonché il suo apporto gnoseologico alla fase dibattimentale. A tale fine, si è proceduto attraverso una iniziale ricognizione evolutiva dell’istituto partendo dalle prime ricostruzioni dottrinali dell’ottocento sino alla normativa attuale. Gli aspetti di maggiore interesse procedimentale hanno avuto ad oggetto, innanzitutto, il tentativo di chiarire i dubbi ermeneutici relativi alla sua classificazione come attività di prevenzione, ovvero come vera e propria ricerca della prova, in funzione repressiva, all’interno di un procedimento penale regolarmente instaurato. Inoltre, si è proceduto all’analisi delle diverse normativa speciali – relative, tutte, a reati di particolare gravità o allarme sociale – che sotto la vigenza del nuovo codice hanno provveduto ad introdurre la possibilità di ricorrere all’agente undercover e, nel dettaglio, a verificare quali siano i rapporti fra i diversi soggetti protagonisti delle indagini preliminari alla luce del necessario inquadramento della disciplina speciale nell’ordinario ambito codicistico di svolgimento delle investigazioni stesse. Un altro importante aspetto della ricerca riguarda la posizione processuale che l’agente sotto copertura, una volta esaurita la sua attività mascherata, viene ad assumere. In tal senso si sono registrate le diverse ricostruzioni dottrinali e giurisprudenziali da un lato orientate al principio del cosiddetto “recupero del sapere investigativo” e dall’altro rivolte a non limitare il diritto di difesa e, ancor di più, il principio del contraddittorio nella formazione della prova, senza dimenticare i fisiologici problemi relativi alla tutela dell’identità dell’agente sotto copertura e della propria incolumità. Tali problematiche sono state affrontate al fine di porre in luce quali siano i riflessi sull’aspetto che indubbiamente suscita il maggior interesse per la sua capacità di influenzare la decisione: l’utilizzazione probatoria dell’attività undercover. Si è infine concluso con una breve indagine comparatistica degli ordinamenti continentali e di common law al fine di trarne utili indicazioni per apporti normativi de iure condendo.
XXI Ciclo
1979
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Araújo, Tatiany Gabrielle Freire 1984. « Influência de solventes nas propriedades físico-químicas de infiltrantes resinosos experimentais = Influence of solvents on the physicochemical properties of exoerimental resin infiltrants ». [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288434.
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Orientador: Americo Bortolazzo CorrerTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O objetivo neste estudo foi avaliar o efeito da adição dos solventes dimetil sulfóxico (DMSO) e tetrahidrofurano (THF) em propriedades físico-químicas de infiltrantes experimentais. Foram preparadas duas blendas resinosas, uma composta por 75%p de TEGDMA (T) e 25%p UDMA (U) e outra por 75%p de T e 25%p de BISEMA (B). Em um grupo de cada mistura não foi adicionado solvente. Os demais grupos foram formulados pela adição dos solventes DMSO ou o THF nas concentrações de 0,5% e 5%. No total foram obtidos 10 infiltrantes experimentais. Icon® foi utilizado como controle. Este estudo foi separado em 2 capítulos. No capitulo 1 o objetivo foi avaliar a influência dos solventes DMSO e THF no ângulo de contato, dureza Knoop em lesões artificiais de cárie infiltradas e a capacidade de penetração dos infiltrantes experimentais em microscópio confocal de varredura a laser. Os dados do ângulo de contato foram submetidos à analise de variância um fator e teste de Tukey, e os de dureza Knoop avaliados por analise de variância dois fatores e teste de Tukey (?=0,05). Os resultados mostraram que o Icon apresentou o menor ângulo de contato. Dentre os infiltrantes experimentais, o menor ângulo de contato foi apresentado pela mistura T + U + 5% DMSO, significativamente menor que as misturas T + U, T + U + 0,5% DMSO, T + U + 5% THF, T + B + 0,5% DMSO e T + B + 0,5% THF. Os resultados de microscopia confocal de varredura a laser mostraram que os infiltrantes apresentaram boa penetração nas lesões artificiais de cárie exceto os grupos T + B, T + B + 0,5% DMSO e T + B + 0,5% THF. As lesões infiltradas por Icon apresentaram dureza significativamente maior que dos outros materiais, exceto T + U + 0,5% DMSO (252,4) e T + U + 5% THF (239,1). Concluiu-se que o Icon apresentou os melhores resultados dentre os materiais avaliados, com menor ângulo de contato, maior dureza e boa penetração. Dentre os materiais experimentais, a incorporação de 5% de DMSO na mistura de U reduziu o ângulo de contato e apresentou dureza semelhante à infiltrada por Icon. No capitulo 2 foi verificada a influência dos solventes DMSO e THF nos infiltrantes experimentais no grau de conversão (GC) (n = 3), resistência coesiva à tração (RT) (n = 10), resistência de união a microtração (RU) (n = 10), resistência a flexão (RF) (n = 10) e módulo de elasticidade (ME) (n = 10). Os dados foram submetidos à ANOVA um fator e teste de Tukey (? = 0,05). Foi verificado que o GC dos infiltrantes com U foi significativamente maior que dos demais infiltrantes. Os infiltrantes experimentais sem solvente apresentaram RF significativamente maior que Icon e que os infiltrantes com solvente. Os infiltrantes com 5% de DMSO apresentaram RU significativamente menor que os demais; Icon apresentou RU significativamente maior que os demais infiltrantes. A RT de Icon foi significativamente maior que dos infiltrantes experimentais. Conclui-se que os solventes DMSO e THF não melhoraram a resistência de união e prejudicaram as propriedades mecânicas dos infiltrantes experimentais. Dentre os solventes, o THF na concentração de 0,5% apresentou menos efeitos deletérios nas propriedades mecânicas dos infiltrantes experimentais. Como conclusão geral, pode ser verificado que o infiltrante Icon apresentou os melhores resultados. Dentre os infiltrantes experimentais, o melhor desempenho foi obtido com a mistura T e U. A adição 0,5% do solvente DMSO na mistura T e U não reduziu o ângulo de contato e reduziu as propriedades mecânicas dos infiltrantes, mas produziu resistência de união e dureza da lesão infiltrada semelhante ao infiltrante Icon
Abstract: The aim of this study was to evaluate the effect of alternative solvents addition dimethyl sulfoxide (DMSO) and tetrahydrofuran (THF) in the chemical-physical properties of experimental infiltrants. Were prepared 2 blends: (1) 75wt% TEGDMA (T) + 25 wt% UDMA (U), (2) 75wt% T + 25wt% BISEMA (B). From each blend were added the solvents DMSO or THF in concentrations of 0.5wt% and 5wt%, totaling 10 experimental groups. Icon® was used as control. This study was divided in 2 chapters. In chapter 1 the aim was to evaluate the influence of alternative solvents (DMSO and THF) in the contact angle, Knoop hardness of artificial caries lesions infiltrated, and the capability of penetration of the experimental infiltrants. Data were analyzed by ANOVA one-way (contact angle) and two-way (Knoop hardness) and Tukey's test (?=0.05). The results showed that Icon presented the lowest contact angle. Analyzing the experimental infiltrants, T + U + 5% DMSO showed the lowest contact angle. The confocal microscopy analysis showed that the infiltrants presented satisfactory penetration into the caries-like lesions except the groups T + B, T + B + 0.5% DMSO and T + B + 0.5% THF. Lesions infiltrated with Icon exhibited hardness values significantly higher than all the experimental groups, except to T + U + 0,5% DMSO (252.4) e T + U + 5% THF (239.1). It is possible to conclude that Icon showed the best results for the tested properties. In chapter 2 was analyzed the influence of the addition of DMSO and THF solvents in experimental infiltrants in relation to degree of conversion (n=3), ultimate tensile strength (n=10), microtensile bond strength (n=10), flexural strength (n=10) and elastic modulus (n=10). Data were submitted to one-way ANOVA and Tukey's test (?=0.05). Infiltrants containing U obtained the highest degree of conversion values. The solvents-free experimental infiltrants showed the highest values of flexural strength. In relation to microtensile bond strength results, the groups with 5% DMSO presented the lowest results and Icon the highest ones. Icon group obtained the highest results of UTS. It is possible to conclude that the addition of solvents DMSO and THF did not improve the bond strength and affected negatively mechanical properties of the experimental infiltrants. THF solvent 0,5% showed less deleterious effects in mechanical properties of experimental infiltrants. Overall, Icon xi obtained the best results. Among the experimental infiltrants, the best performance was obtained by the association of T and U. The addition of 0.5% of DMSO in the blend T + U did not reduce the contact angle and affected negatively the mechanical properties, except to microtensile bond strength and hardness of the caries lesions infiltrated
Doutorado
Materiais Dentarios
Doutora em Materiais Dentários
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Carvalho, Eufrosina Terezinha Leão. « Avaliação de elementos de infiltração de águas pluviais na zona norte da cidade de Goiânia ». Universidade Federal de Goiás, 2008. http://repositorio.bc.ufg.br/tede/handle/tede/5711.
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The development of the urban environment results in an expansion of impervious ground surfaces that greatly affects the hydrological cycle in the cities. The objective of this research is to evaluate infiltration structures for the control of excess drainage at the origin of runoff. These structures are constructed with the purpose of minimizing the impact of impervious surfaces to the urban environment. An experimental field was established consisting of several infiltration structures, such as small-diameter pilot wells and real scale wells. The real scale wells used perforated concrete pipe casing and brick lining. Falling-head infiltration tests were carried out during 15 months, encompassing the dry and rainy seasons. The infiltration tests were undertaken with initial conditions that correspond to the natural water content at the time of testing. Additional tests were undertaken with previously flooded conditions, reproducing several consecutive rainy days. The monitoring of pilot wells along with real scale wells allowed the evaluation of project parameters obtained from pilot wells. The values of average infiltration rate of different infiltration wells were compared and the performance of the several structures was compared. Laboratory test were carried out for the determination of the hydraulic parameters of the ground profile, including the saturated hydraulic conductivity the soil-water characteristic curve. A numerical model for the simulation of infiltration wells was implemented using the software FlexPDE. Special boundary conditions were developed that take into account the transient relationship between the varying hydraulic head at the well walls and the total volume infiltrated during a test. The numerical simulations contributed for a better understanding of the infiltration mechanism, the influence of the hydraulic conductivity to the infiltration rate, and the determination of the wetting front and pore-water pressures during infiltration. A design criterion for infiltration wells was proposed using daily compensation, considering the daily water balance during 25 years, and the precipitation historical series of the site. The proposed design criterion makes possible the selection of the group of infiltration structures that meet the project goals. The design criterion also allowed the evaluation of the theoretical performance of wells designed using two conventional criteria
A expansão do ambiente urbano causa o aumento das superfícies impermeabilizadas, alterando o ciclo hidrológico nas cidades. Esta pesquisa buscou avaliar estruturas de infiltração para o controle de fluxos superficiais na fonte, construídas com a finalidade de minimizar os impactos da impermeabilização nas cidades. Foi estabelecido um campo experimental composto por diversas estruturas de infiltração, incluindo poços piloto de pequeno diâmetro e poços em escala real. Os poços em escala real foram revestidos em tubo de concreto perfurado e em tijolo maciço assentado em crivo. Ensaios de infiltração com carga variável foram realizados durante 15 meses, abrangendo as estações seca e chuvosa. Os ensaios de infiltração foram realizados em condição inicial de umidade natural e em condição pré-inundada, procurando reproduzir vários dias consecutivos de chuva. O monitoramento dos poços piloto, juntamente com estruturas de infiltração em escala real, permitiu a avaliação dos parâmetros de projetos obtidos a partir dos poços piloto. Os valores de taxa de infiltração média foram comparados entre os diferentes elementos de infiltração e permitiram comparar o desempenho das estruturas. Foram realizados ensaios de laboratório para obtenção de parâmetros hidráulicos do perfil de solo do campo experimental. Dentre as propriedades avaliadas destacam-se a permeabilidade do solo saturado e a curva característica. Um modelo numérico foi implementado utilizando o programa FlexPDE. Foram desenvolvidas condições de fronteira especiais que consideram a dependência transiente entre a carga hidráulica nas paredes do poço e o volume total infiltrado durante o ensaio. A simulação numérica permitiu o melhor entendimento do mecanismo de infiltração, a influência da permeabilidade na taxa de infiltração e a determinação da frente de saturação e da distribuição de poro-pressão durante a infiltração. Foi proposto um critério de dimensionamento de poços de infiltração através da compensação diária, analisando todos os dias durante 25 anos e utilizando a série histórica de chuvas da região. Esse critério permite selecionar e dimensionar a estrutura ou um grupo de estruturas que melhor atenda ao projeto. O critério proposto permitiu também avaliar o desempenho teórico de sistemas dimensionados utilizando dois critérios convencionais
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Ribeiro, Mara Fernandes. « Ação do veneno da aranha marrom (Loxosceles Intermedia) em camundongos ». Niterói, 2017. https://app.uff.br/riuff/handle/1/3351.
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Os acidentes causados por aranhas do gênero Loxosceles representam importante problema de saúde pública no Brasil, sendo as principais espécies de importância médica L. intermedia, L. laeta e L. gaucho. O veneno dessas aranhas promove grave dermonecrose no local da picada, e menos comumente, doença sistêmica que pode ser fatal. O mecanismo de ação desse veneno não está completamente elucidado, trata-se de um processo multifatorial, que envolve a ação direta do veneno sobre os tecidos e a resposta do organismo a agressão causada pelo mesmo. Os camundongos constituem o modelo experimental menos susceptível ao desenvolvimento dos efeitos locais decorrentes do envenenamento por aranhas Loxosceles, dessa forma, sua utilização representa grande interesse clínico, cujo objetivo é desvendar tal mecanismo de proteção presente nestes animais. Este trabalho teve como objetivo caracterizar as atividades do veneno de Loxosceles intermedia, bem como avaliar as atividades in vivo deste veneno em camundongos. A manipulação e os procedimentos com os animais obedeceram aos princípios da CEUA/UFF (Comissão de Ética no Uso de Animais da Universidade Federal Fluminense). Foi demonstrado, in vitro, que o veneno de L. intermedia não apresenta atividade fosfolipásica A2, a atividade hialuronidásica e colágenásica foram dependente da concentração do veneno enquanto que a atividade proteolítica e esfingomielinásica foram observadas apenas em altas concentrações. Para descrever as ações do veneno de L. intermedia em camundongos, foi proposta a utilização de três diferentes linhagens: BALB/c, C57BL/6 e Suiço. A atividade edematogênica na pata dos camundongos inoculados com o veneno foi observada para as três linhagens testadas, sendo persistente por 24 horas, apenas para as linhagens BALB/c e C57BL/6. A análise histopatológica do local de inoculação intradérmica do veneno no abdomen apresentou diferenças relevantes, como, intensa congestão vascular em Suiços e presença de infiltrado inflamatório no local de inoculação na pele de BALB/c e C57BL/6. A partir destes achados, investigou-se a mobilização de células inflamatórias a partir da medula óssea, no baço e no sangue por citometria de fluxo, que demonstrou resposta imunológica inata típica, com aumento da cinética de células mieloides e linfócitos T citotóxicos para camundongos C57BL/6, e resposta tipicamente adquirida/humoral, com aumento preferencial de linfócitos B convencionais e T auxiliar para camundongos BALB/c. Desta forma, este trabalho demonstrou que modelos animais semelhantes podem apresentar diferentes respostas a inoculação deste veneno. A presença do infiltrado inflamatório no local de inoculação do veneno e a mobilização de células inflamatórias a partir da medula óssea, baço e sangue revelaram que diferentes linhagens de camundongos apresentam diferenças no tipo celular envolvido na resposta imunológica decorrente do envenenamento ou esta diferença pode estar relacionada ao tempo e velocidade da resposta em cada linhagem de camundongos. A partir destes resultados este trabalho sugere que camundongos da linhagem BALB/c podem ser utilizados como modelo para estudar a produção de IgM e IgG induzido pelo veneno, incluindo análise de citocinas, quimiocinas e mecanismos moleculares, por outro lado camundongos C57BL/6 podem ser utilizados para descrever a participação de células mielóides durante o envenenamento por aranhas do gênero Loxosceles
Accidents caused by spiders of the genus Loxosceles represent an important public health problem in Brazil, being the major species of medical importance L. intermedia, L. laeta and L. gaucho. The venom of these spiders induces an intense dermonecrosis at the bite site, and less commonly, systemic disease that can be fatal. The mechanism of action of this venom is not fully elucidated, it is a multifactorial process, which involves the direct action of the venom on the tissues and the body's response to aggression caused by it. The mice are an experimental model less susceptible to development the local effects of poisoning Loxosceles spiders. Thus, their use is great clinical interest, whose goal is to unravel the mechanism of this protection in these animals. This study aimed to characterize the activities of Loxosceles intermedia venom, as well as evaluating the in vivo activity of this venom in mice. Manipulation and procedures with animals obeyed the principles of CEUA / UFF (Ethics Committee on Animal Use Universidade Federal Fluminense). It has been shown in vitro that the venom of L. intermedia shows no phospholipase A2 activity and the hyaluronidase and collagenase were dependent on the concentration of the poison and while the proteolytic and sphingomyelinase activity were observed only at high concentrations. To describe the actions of the venom of L. intermedia in mice, it was proposed to use three different strains: BALB/c, C57BL/6 and Swiss. The activity in the paw edema of mice inoculated with the venom was observed for the three strains tested, being persistent for 24 hours, only for the strains BALB/c and C57BL/6. Histopathological analysis of the site of venom intradermal inoculation in the abdomen showed significant differences, as intense vascular congestion in Swiss and inflammatory infiltration at the site of inoculation in the skin of BALB/c and C57BL/6. From these findings, we investigated the mobilization of inflammatory cells from the bone marrow, spleen like effector organ, and migration into the blood by flow cytometry, which showed a typical innate immune response, with increased kinetics of myeloid cells and cytotoxic T lymphocytes to C57BL/6 mice, and response typically acquired / humoral, with a preferential increase of conventional B lymphocytes and T helper to BALB/c mice. Thus, this study demonstrated that similar animal models may have different responses to inoculation of this venom. The presence of the inflammatory infiltrate at the site of inoculation of the venom and the mobilization of inflammatory cells from the bone marrow, spleen and blood revealed that different strains of mice differ in cell type involved in the immune response resulting from poisoning and this difference can be related time and speed of response for each strain of mice. From these results, this study suggests that BALB/c mice can be used as a model to study the production of IgM and IgG induced by the venom, including analysis of cytokines, chemokines and molecular mechanisms, on the other hand C57BL/6 mice can be used to describe the involvement of myeloid cells during poisoning by spiders of the genus Loxosceles
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Oliveira, Verena Benício de. « Avaliação da infiltração da água no solo utilizando modelos determinísticos ». Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-24042015-085017/.
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A infiltração é o processo pelo qual a água atravessa a superfície do solo, com grande importância para a hidrologia, irrigação e agricultura. À medida que a água infiltra, as camadas superiores do solo vão se umedecendo, alterando gradativamente o perfil de umidade. Sob condições de campo, a água que infiltra pode fluir tanto na vertical, como na horizontal, dependendo do tipo de solo e declividade do terreno. A taxa de infiltração da água no solo é afetada, principalmente, pelas características do solo que afetam a geometria de seu sistema poroso, como textura e estrutura, e pode ser determinada tanto no campo como em laboratório, por diferentes métodos. Com a intenção de otimizar a previsão da infiltração da água no solo, diversos modelos foram desenvolvidos, podendo ser classificados em três grupos: empíricos, semi-empíricos e com base física. O objetivo deste trabalho foi avaliar a infiltração de água em solos com diferentes texturas e comparar a qualidade do ajuste de diferentes modelos usualmente empregados. As curvas da taxa de infiltração e da infiltração acumulada foram determinadas em laboratório utilizando amostras de solo homogeneamente acondicionadas em colunas e comparadas pelos seguintes modelos: Kostiakov, Horton, Green & Ampt, e Philip. Dentre os solos estudados, o solo 3 (textura franco arenosa) foi o que apresentou a maior taxa de infiltração e a maior VIB, provavelmente devido a menor proporção de argila e maior presença de macroporos, facilitando a infiltração da água no solo. Dos modelos analisados, o de Kostiakov, seguido pelo de Philip, foram os que apresentaram em média os melhores valores estimados da taxa de infiltração quando comparados com os valores medidos em laboratório. O gráfico do avanço da frente de molhamento com a raiz quadrada do tempo de infiltração (horizontal) ajustou-se perfeitamente ao modelo de Philip. No que respeita a infiltração vertical tal gráfico foi semelhante ao da horizontal (linha reta), mas com maior inclinação.Infiltration is the process in which the water passes through the soil surface, being of great importance for hydrology, irrigation and agriculture. As the water infiltrates, the soil water content profile will changing and the infiltrated water can flow vertically or horizontally, depending on the soil type and land slope. The soil water infiltration rate is mainly affected by soil properties that affect its porous geometry, such as texture and structure, and can be determined in the field and in the laboratory, using different methods. In order to optimize the prediction of the soil water infiltration, many different models have been developed and may be classified into three groups: empirical, semi-empirical and physically based. The objective of this study was to evaluate the water infiltration in soils with different textures and compare the quality of fit of the different used models. The infiltration rate curves and the cumulative infiltration curves were determined in the laboratory using soil samples homogeneously packed in column and compared by the following models: Kostiakov, Horton, Green & Ampt and Philip. Among the studied soils, the soil 3 (sandy loam texture) presented the highest infiltration rate and the highest basic infiltration rate, probably due to lower clay content and larger quantity of macropores, facilitating the water infiltration into the soil. Among the tested models, Kostiakov, followed by Philip, presented, on average, the best estimated values of the infiltration rate compared to the values measured in the laboratory. The front of the advancing wetting graph of the square root of the infiltration time (horizontal) well set to Philip model. With respect to this vertical graph infiltration was similar to the horizontal (straight line) but more inclined.
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CARVALHO, Eufrosina Terezinha Leão. « Avaliação de elementos de infiltração de águas pluviais na zona norte da cidade de Goiânia ». Universidade Federal de Goiás, 2009. http://repositorio.bc.ufg.br/tede/handle/tde/1352.
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Previous issue date: 2009-08-29The development of the urban environment results in an expansion of impervious ground surfaces that greatly affects the hydrological cycle in the cities. The objective of this research is to evaluate infiltration structures for the control of excess drainage at the origin of runoff. These structures are constructed with the purpose of minimizing the impact of impervious surfaces to the urban environment. An experimental field was established consisting of several infiltration structures, such as small-diameter pilot wells and real scale wells. The real scale wells used perforated concrete pipe casing and brick lining. Falling-head infiltration tests were carried out during 15 months, encompassing the dry and rainy seasons. The infiltration tests were undertaken with initial conditions that correspond to the natural water content at the time of testing. Additional tests were undertaken with previously flooded conditions, reproducing several consecutive rainy days. The monitoring of pilot wells along with real scale wells allowed the evaluation of project parameters obtained from pilot wells. The values of average infiltration rate of different infiltration wells were compared and the performance of the several structures was compared. Laboratory test were carried out for the determination of the hydraulic parameters of the ground profile, including the saturated hydraulic conductivity the soil-water characteristic curve. A numerical model for the simulation of infiltration wells was implemented using the software FlexPDE. Special boundary conditions were developed that take into account the transient relationship between the varying hydraulic head at the well walls and the total volume infiltrated during a test. The numerical simulations contributed for a better understanding of the infiltration mechanism, the influence of the hydraulic conductivity to the infiltration rate, and the determination of the wetting front and pore-water pressures during infiltration. A design criterion for infiltration wells was proposed using daily compensation, considering the daily water balance during 25 years, and the precipitation historical series of the site. The proposed design criterion makes possible the selection of the group of infiltration structures that meet the project goals. The design criterion also allowed the evaluation of the theoretical performance of wells designed using two conventional criteria
A expansão do ambiente urbano causa o aumento das superfícies impermeabilizadas, alterando o ciclo hidrológico nas cidades. Esta pesquisa buscou avaliar estruturas de infiltração para o controle de fluxos superficiais na fonte, construídas com a finalidade de minimizar os impactos da impermeabilização nas cidades. Foi estabelecido um campo experimental composto por diversas estruturas de infiltração, incluindo poços piloto de pequeno diâmetro e poços em escala real. Os poços em escala real foram revestidos em tubo de concreto perfurado e em tijolo maciço assentado em crivo. Ensaios de infiltração com carga variável foram realizados durante 15 meses, abrangendo as estações seca e chuvosa. Os ensaios de infiltração foram realizados em condição inicial de umidade natural e em condição pré-inundada, procurando reproduzir vários dias consecutivos de chuva. O monitoramento dos poços piloto, juntamente com estruturas de infiltração em escala real, permitiu a avaliação dos parâmetros de projetos obtidos a partir dos poços piloto. Os valores de taxa de infiltração média foram comparados entre os diferentes elementos de infiltração e permitiram comparar o desempenho das estruturas. Foram realizados ensaios de laboratório para obtenção de parâmetros hidráulicos do perfil de solo do campo experimental. Dentre as propriedades avaliadas destacam-se a permeabilidade do solo saturado e a curva característica. Um modelo numérico foi implementado utilizando o programa FlexPDE. Foram desenvolvidas condições de fronteira especiais que consideram a dependência transiente entre a carga hidráulica nas paredes do poço e o volume total infiltrado durante o ensaio. A simulação numérica permitiu o melhor entendimento do mecanismo de infiltração, a influência da permeabilidade na taxa de infiltração e a determinação da frente de saturação e da distribuição de poro-pressão durante a infiltração. Foi proposto um critério de dimensionamento de poços de infiltração através da compensação diária, analisando todos os dias durante 25 anos e utilizando a série histórica de chuvas da região. Esse critério permite selecionar e dimensionar a estrutura ou um grupo de estruturas que melhor atenda ao projeto. O critério proposto permitiu também avaliar o desempenho teórico de sistemas dimensionados utilizando dois critérios convencionais
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Snow, Daniel Owens. « Modeling and Effects of Non-Homogeneous Infiltration on Material Properties of Carbon-Infiltrated Carbon Nanotube Forests ». BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/9216.
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This work investigates the material properties and production parameters of carbon infiltrated carbon nanotube structures (CI-CNT's). The impact of non homogeneous infiltration and the porosity of cross section regions, coupled with changes in designed geometry, in this case beam width, on the density and modulus of elasticity are compared. Three potential geometric models of beam cross section are proposed and evaluated. 3-point bending, SEM images, and numerical optimization are used to assess the validity of each model and the implications they have for future CI-CNT material applications. Carbon capping near exterior beam surfaces is observed and determined to be a contributing factor to variations in material properties correlated with changes in designed geometry and infiltration parameters (temperature, time, and hydrogen flow rate). Unexpected relationships between beam width and elastic modulus are partially explained by modeling the carbon-capped beams as C-shaped structural members consisting of a graphitic carbon shell of varying porosity and thickness and uninfiltrated carbon nanotube internal regions with a near negligible stiffness. Findings of previous works on the effects of infiltration parameters and carbon capping on materials properties are confirmed and expanded. Flange and web thickness and porosity of the graphitic carbon shell are identified as potential design parameters for pursuing tunable material properties in high precision geometry MEMS and compliant mechanism applications.
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Martins, Patrícia Diniz. « Estudo de infiltração e recarga direta em um lisímetro de laboratório ». [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258609.
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Orientador: José Anderson Batista do NascimentoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
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Resumo: Estudos sobre a infiltração de água no solo são importantes para a determinação do escoamento superficial direto e da recarga direta de aquíferos, essenciais para a quantificação dos recursos hídricos. O presente trabalho tem com objetivo estudar os processos de produção de escoamento superficial e recarga direta de aquíferos por meio de um lisímetro de gravidade com amostra indeformada em escala de campo ensaiado em laboratório. O lisímetro foi construído a partir da retirada de uma amostra de solo com 0,6 m de diâmetro e 1,7 m de profundidade. Os procedimentos de escavação, transporte e instalação do lisímetro foram realizados dentro de um período de 6,25 horas, tempo inferior à instrumentação de uma bacia. Foi observado um amalgamento da amostra após a cravação de 0,20 m; correspondente a 10,5% da altura total de cravação, que é compatível com índices obtidos de amostradores. Foram realizadas simulações de eventos chuvosos no topo da amostra, correspondentes a uma chuva intensa de tempo de retorno de 10 anos com intervalo de sete dias e as tensões mátricas antecedentes e decorrentes dos ensaios ao longo da profundidade foram monitoradas. Os eventos chuvosos ensaiados não produziram escoamento superficial direto, porém a capacidade de infiltração foi caracterizada. A partir da obtenção de curvas de retenção para a amostra, a recarga direta foi observada com menores valores em períodos de menor umidade que correspondem às maiores tensão mátricas encontradas (15 a 58 kPa). Os maiores valores ocorreram após os eventos de precipitação. As tensões mátricas antecedentes caíram até a faixa de 0,2 a 4 kPa durante os períodos de ensaios. O uso de lisímetro em laboratório não substitui a prática de instrumentação de bacias nem o uso de lisímetros em campo. Considera-se que o uso de lisímetro em laboratório acarreta em condições ainda artificiais principalmente de precipitação e escoamento superficial direto. Ainda assim, a experimentação de uma amostra de solo indeformado em escala vertical de campo em laboratório, de acordo com os resultados obtidos neste trabalho, representa de forma aproximada o comportamento real da infiltração, percolação e produção de escoamento superficial direto encontrado em um perfil litológico raso
Abstract: Studies on water infiltration in soil are important for determining the runoff and direct recharge of aquifers, which are essential for the quantification of water resources. The goal of this work is to study the production processes of runoff and direct recharge of aquifers through a gravity lysimeter with undisturbed sample scale field tested in the laboratory. The lysimeter was constructed from the withdrawal of a soil sample with 0.6 m diameter and 1.7 m deep. The procedures for excavation, transportation and installation of the lysimeter were performed within a period of 6.25 hours, less time instrumentation of a watershed. We observed an amalgamation of the sample after the crimping of 0.20 m; corresponding to 10.5% of the total height of crimping, which is compatible with indices obtained from samplers. We simulated rainfall events on top of the sample, corresponding to an intense rain of turnaround time of 10 years with an interval of seven days and the tensions arising mátricas antecedents and tests along the depth were monitored. The rainfall events tested did not produce runoff, but the infiltration capacity was characterized. Upon obtaining retention curves for the sample, direct recharge was observed with lower values during periods of reduced moisture that correspond to higher voltage mátricas found (15-58 kPa). The highest values occurred after rainfall events. The voltages fell to background mátricas range of 0.2 to 4 kPa during periods of testing. The use of laboratory lysimeter does not replace the practice of instrumentation basins or the use of lysimeters in the field. It is considered that the use of lysimeter laboratory conditions still entails primarily artificial precipitation and runoff. Nevertheless, the experimentation of a sample of undisturbed soil at field vertical scale in the laboratory, according to the results obtained in this study represents an approximation of the actual behavior infiltration and seepage runoff production of a profile found in lithology shallow
Mestrado
Recursos Hidricos, Energeticos e Ambientais
Mestra em Engenharia Civil
Livres sur le sujet "Infiltrato"
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Tosi, Giorgio Sturlese. Una vita da infiltrato. [Milan, Italy] : BUR Rizzoli, 2010.
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Gatti, Fabrizio. Bilal : Il mio viaggio da infiltrato nel mercato dei nuovi schiavi. 2e éd. [Milan, Italy] : BUR, 2008.
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Bilal : Il mio viaggio da infiltrato nel mercato dei nuovi schiavi. [Milan, Italy] : Rizzoli, 2007.
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Favero, Gianni. Undercover : Undici mesi da infiltrato : [un carabiniere veneto contro la camorra]. Venezia : Studio LT2, 2008.
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Vite in cambio : Gianni Mineo, il partigiano infiltrato, che salvò dalla strage la popolazione della Chiassa. Arcidosso (GR) : Edizioni Effigi, 2014.
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Singer, A. L. Infiltrator. New York, NY : Scholastic Inc., 1991.
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Infiltrator. New York : Pocket Books, 1996.
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Stirling, S. M. T2 : Infiltrator. New York : HarperEntertainment, 2001.
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Collyer, Jaime. El infiltrado. Madrid : Mondadori, 1989.
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Dalya, Bilu, dir. Infiltration. South Royalton, Vt : Zoland Books, 2003.
Trouver le texte intégralChapitres de livres sur le sujet "Infiltrato"
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Bährle-Rapp, Marina. « Infiltrat ». Dans Springer Lexikon Kosmetik und Körperpflege, 279. Berlin, Heidelberg : Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_5188.
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Vieux, Baxter E. « Infiltration ». Dans Water Science and Technology Library, 83–99. Dordrecht : Springer Netherlands, 2016. http://dx.doi.org/10.1007/978-94-024-0930-7_5.
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Gargouri-Ellouze, Emna, Saeid Eslamian, Kaveh Ostad-Ali-Askari, Rim Chérif, Maroua Bouteffeha et Fairouz Slama. « Infiltration ». Dans Selective Neck Dissection for Oral Cancer, 1–3. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-12127-7_169-1.
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Vieux, Baxter E. « Infiltration ». Dans Water Science and Technology Library, 95–120. Dordrecht : Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-015-9710-4_5.
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Perrier, E. R., et A. B. Salkini. « Infiltration ». Dans Supplemental Irrigation in the Near East and North Africa, 133–44. Dordrecht : Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3766-9_9.
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Gargouri-Ellouze, Emna, Saeid Eslamian, Kaveh Ostad-Ali-Askari, Rim Chérif, Maroua Bouteffeha et Fairouz Slama. « Infiltration ». Dans Encyclopedia of Earth Sciences Series, 513–15. Cham : Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-73568-9_169.
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Chesworth, Ward, Augusto Perez‐Alberti, Emmanuelle Arnaud, H. J. Morel‐Seytoux et H. J. Morel‐Seytoux. « Infiltration ». Dans Encyclopedia of Soil Science, 350–62. Dordrecht : Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-3995-9_291.
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Bährle-Rapp, Marina. « Infiltration ». Dans Springer Lexikon Kosmetik und Körperpflege, 279. Berlin, Heidelberg : Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_5189.
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Iwata, Yukiyoshi. « Snowmelt Infiltration ». Dans Encyclopedia of Agrophysics, 736. Dordrecht : Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-90-481-3585-1_140.
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Dail, David H. « Eosinophilic Infiltrates ». Dans Pulmonary Pathology, 359–78. New York, NY : Springer New York, 1988. http://dx.doi.org/10.1007/978-1-4757-3932-9_13.
Texte intégralActes de conférences sur le sujet "Infiltrato"
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He, Zhoutong, Hui Tang, Can Zhang, Yantao Gao, Huihao Xia et Xingtai Zhou. « The Compatibility of Nuclear Graphite With Molten Salt in the Molten Salt Reactor ». Dans 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-82065.
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In thermal Molten Salt Reactors, the nuclear graphite core is in direct contact with the molten salt coolant. Due to the porous nature of nuclear graphite, the molten salt may infiltrate the nuclear graphite, which may affect the mechanical strength and irradiation behavior of the nuclear graphite. In order to evaluate the infiltration behavior of molten salt in nuclear graphite, both FLiNaK and FLiBe salts were used to infiltrate two typical nuclear graphite grades: IG110 and NBG18. The pressure dependence of the infiltration weight gain ratio was measured. The influence of molten salt infiltration on the thermal properties of these two graphite grades, such as their thermal expansion behavior and thermal conductivity, was also measured. The mechanical strength of the FLiNaK-infiltrated graphite was measured at room temperature and elevated temperature, and showed that the mechanical strength of the nuclear graphite was enhanced at room temperature and weakened at elevated temperature by molten salt infiltration. Finally, the thermal expansion coefficient and the fracture surface analysis measured after FLiNaK infiltration indicated that the stress induced by molten salt infiltration could be one of the reasons for the graphite property changes.
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Wang, Xiao, Yongtu Liang, Shengli Liu et Mengyu Wu. « Analysis of Products Pipeline Accident Infiltration Process in Surface Soil Condition ». Dans ASME 2019 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/pvp2019-93069.
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Abstract The most common way of transportation for refined oil is long-distance pipeline. Pipeline accidents occur frequently due to corrosion, equipment failure, external forces destruction. Aiming at predicting the contaminated area in soil caused by products pipeline accidents, this experimental study was conducted to examine the relationship between the light non-aqueous phase liquids (LNAPL) accumulative infiltrate volume and the time of infiltration process in homogeneous and layered soils. The soil’s hydraulic parameters were obtained by basic experiments and RETC software. Compared with traditional infiltration mathematical model, Green-Ampt model is the most common mathematical model to calculate the infiltration process in the unsaturated soil. In this study, a modified Green-Ampt model was developed to describe water and diesel infiltration through a 100-cm-long and layered soil column. In the modified Green-Ampt model, an infiltration reduction ratio was introduced to describe the effect of the hydraulic conductivity of the layered position. To evaluate the proposed method in the effect of the layers position infiltration permeability, eight constant water head layered column infiltration experiment were conducted to record the different infiltration fluid and different constant water head infiltration process. Compared the experiment results with traditional mathematical traditional Green-Ampt model (average R2 = 0.976) and Hydrus-1D software (average R2 = 0.988) The modified Green-Ampt model had relatively higher precision in accumulative infiltrate volume (average R2 = 0.992) and the wetting front velocity in infiltration process (average R2 = 0.997). Thus, the modified mathematical model was applied an effective upscaling scheme in layered formations. The experimental result also demonstrated that soil layering affected the infiltration process. With the increase of soil depth and density, the infiltration speed of the layered soil column decreased. Additionally, the infiltrate speed of wetting front decreases slowly at the layered surface. The experiment’s fitting results showed that the modified mathematical model about infiltrate time and liquid contaminant accumulative infiltrate volume, wetting front infiltrate velocity can highly effective approach to simulate water and light non-aqueous phase liquids (LNAPL) infiltration process in layered soils.
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Balagangadhar, Dinesh, et Gopalaswamy Rajesh. « Macro Modeling of Reactive Infiltration Using Level Set Finite Element Formulations ». Dans ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-1239.
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Abstract The process of reactive melt infiltration can be used to fabricate ceramics and ceramic matrix composites. This process involves a liquid metal being allowed to infiltrate a medium with which the liquid reacts to form a resultant ‘matrix’ along with the already present reinforcing fibers. The authors’ previous work on this area revealed that the transient porosity and permeability of a porous medium can be determined for certain geometries from the reaction kinetics and coupled heat and mass transfer problem occurring at the pore level. But the formulation at the macro level, which is essential to optimize the process, has been limited. Towards this end, this paper solves the macro reactive flow problem in a porous medium analytically as well as numerically. The focus of this article will be on the solutions for the advance (displacement) of the ‘infiltration front’ with progressive chemical reaction occurring between the medium and the infiltrant. A finite element formulation is used to solve the problem computationally; a level set formulation is used to track the infiltration front during the process. Excellent agreement is obtained between the analytical and computational solutions thereby validating the level set finite element formulations.
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Bourell, David L., Phani Vallabhajosyula, Brooke Stevinson, Ssuwei Chen et Joseph J. Beaman. « Rapid Manufacturing Using Infiltration Selective Laser Sintering ». Dans ASME 2008 9th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2008. http://dx.doi.org/10.1115/esda2008-59084.
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Selective Laser Sintering (SLS) is tooless, computer-controlled layerwise additive manufacturing using a laser and a powder bed. The scanning laser locally melts the surface of a powder bed selectively, followed by deposition of a fresh layer of powder and repetition of the process. SLS has been developed for plastic powder. Creation of non-metallics and metal parts is more challenging. One approach is to mix the master powder with a transient binder. SLS melts the binder which wets the master powder, creating a green part. Subsequent post-processing is required to either remove the binder or convert it to a usable form. The last step is infiltration with a molten substance. Fundamentals of infiltration theory will be reviewed. A study of dimensional changes associated with various stages of processing reveals that overall linear dimensions vary less than one percent compared to the computer solid model. Several examples demonstrating the utility of an infiltration approach to freeform fabrication will be presented. These include silicon carbide with a phenolic binder, infiltrated with silicon; graphite with a phenolic binder infiltrated with epoxy; and tool steel with a proprietary low-ash binder infiltrated with cast iron.
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Sayre, Jay R., et Alfred C. Loos. « Resin Infusion of Triaxially Braided Preforms With Through-the-Thickness Reinforcement ». Dans ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/htd-24361.
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Abstract Vacuum assisted resin transfer molding (VARTM) has shown potential to significantly reduce the manufacturing cost of high-performance aerospace composite structures. In this investigation, high fiber volume fraction, triaxially braided preforms with through-the-thickness stitching were successfully resin infiltrated by the VARTM process. The preforms, resin infiltrated with three different resin systems, produced cured composites that were fully wet-out and void free. A three-dimensional finite element model was used to simulation resin infusion into the preforms. The predicted flow patterns agreed well with the flow pattern observed during the infiltration process. The total infiltration times calculated using the model compared well with the measured times.
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Tucker, David, Ayyakkannu Manivannan, Dan Haynes, Harry Abernathy, Nick Miller, Karon Wynne et Angine´s Matos. « Evaluating Methods for Infiltration of LSCF Cathodes With Mixed Electric/Ionic Conductors for Improved Oxygen Exchange ». Dans ASME 2010 8th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2010. http://dx.doi.org/10.1115/fuelcell2010-33214.
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Infiltration methods for improving lanthanum strontium cobalt ferrite (LSCF) cathode performance through catalyst surface modification were evaluated at the U.S. Department of Energy, National Energy Technology Laboratory. Infiltration of mixed conductors into LSCF cathodes of solid oxide fuel cells promises a low cost method of improving oxygen exchange and performance in these materials at lower temperatures. LSCF cathodes on Nickel-Yttria Stabilized Zirconia (Ni-YSZ) anode supported cells were infiltrated with strontium-doped lanthanum zirconate (LSZ) pyrochlores using two methods. An aqueous solution of nitrate salts was vacuum infiltrated into the cathodes of anode supported button cells, and the cells were heated to form the pyrochlore phase in-situ. This was compared to the efficacy of infiltrating a suspension of pyrochlore nanoparticles. Different dispersants were used to prepare the nanoparticle suspensions at varying concentrations and pH levels, and the results are compared.
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Li, C. J., G. J. Yang et A. Ohmori. « Improvement of the Properties of Thermally Sprayed Ceramic Coating by the Infiltration of the Adhesives ». Dans ITSC2003, sous la direction de Basil R. Marple et Christian Moreau. ASM International, 2003. http://dx.doi.org/10.31399/asm.cp.itsc2003p1311.
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Abstract Thermally sprayed ceramic coating consists generally of porosity up to over ten percent. The existence of voids in the coating will degrade mechanical performance and corrosion resistance. The infiltration technique has been used to enhance the coating performance. In the present work, the adhesives of high strength are used as infiltrator for plasma sprayed alumina coatings to investigate the effect of the infiltration on the adhesive strength and erosion resistance. The adhesive strength of coating after infiltration is tested following ASTM-C-633 standard with the same adhesive. The commercial adhesives used are liquid types of adhesives. Alumina coatings are deposited by plasma spraying to a thickness about 500ìm. The adhesive strength of as-sprayed coating was tested using another epoxy resin adhesive. The test pieces are prepared without infiltration of adhesive into the coating. The results revealed that the infiltration of adhesive to alumina coating can improve significantly the adhesive strength and erosion resistance. The adhesive strength from 40 to 55 MPa can be obtained in spite of deposition conditions. The erosion resistance of the coating at 90 degrees can be improved by a factor about 3.
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Farahani, Rouhollah Dermanaki, Hamid Dalir, Martin Le´vesque et Daniel Therriault. « Mechanical Properties of Three-Dimensional Microstructures Infiltrated by Carbon Nanotube/Epoxy Nanocomposite Under Shear Flow ». Dans ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-39086.
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Three-dimensional interconnected microfluidic channels fabricated by the direct-write method were infiltrated with SWCNT/epoxy nanocomposites under high shear flow to mechanically characterize the effect of single-walled carbon nanotubes (SWCNTs) spatial orientation in thermosetting-matrix nanocomposites. The micron-size fugitive ink filaments were deposited layer by layer in order to form a scaffold followed by its encapsulation by an epoxy resin. Three-dimensional interconnected microfluidic channels were then obtained by heat curing the encapsulated epoxy followed by fugitive ink removal by liquefying it at high temperature under vacuum. To debundle the Laser-ablated single-walled carbon nanotubes (La-SWNTs), nitric acid treatment following introduction of protoporphyrin IX as surfactant were done to prevent reclustering of the CNTs after separation. La-SWNTs were then mixed with ultraviolet-curable epoxy using a three-roll mill machine to achieve a well-dispersed nanocomposite. The nanocomposites were then infiltrated within the empty channels at high pressures to induce shear. High shear flow infiltration of nanocomposites will cause the CNTs to be aligned in the direction of the channels where an increase in shear leads to an increase in CNT alignments. Finally, in order to mechanically investigate the effectiveness of the infiltration technique and the orientation of SWCNTs, tensile and three-point bending tests were done.
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James, Sagil, et Cristian Navarro. « Molecular Dynamics Simulation of Nanoparticle Infiltration During Binder Jet Printing Additive Manufacturing Process : A Preliminary Study ». Dans ASME 2019 14th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/msec2019-2872.
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Abstract Binder Jetting Process involves binding layers of powder material through selective deposition of a liquid binder. Binder jetting is a fast and relatively inexpensive process which does not require a high-powered energy source for printing purpose. Additionally, the binder jetting process is capable of producing parts with extreme complexities without using any support structures. These characteristics make binder jetting an ideal choice for several applications including aerospace, biomedical, energy, and several other industries. However, a significant limitation of binder jetting process is its inability to produce printed parts with full density thereby resulting in highly porous structures. A possible solution to overcome the porosity problems is to infiltrate the printed structures with low-melting nanoparticles. The infiltrating nanoparticles help fill up the voids to densify the printed parts and also aids in the sintering of the printed green parts. In addition to increasing the density, the nanoparticle infiltration also helps improve the mechanical, thermal and electrical properties of the printed part along with bringing multi-functionality aspect. Currently, there is a lack of clarity of the nanoparticle infiltration process performed to improve the quality of parts fabricated through binder jetting. This research employs Molecular Dynamics simulation techniques to investigate the nanoparticle infiltration during binder jetting additive manufacturing process. The simulation is performed at different operating temperatures of 1400 K, 1500 K, and 1600 K. The study found that the infiltration process is significantly affected by the operating temperature. The infiltration height is found to be highest at the operating temperature of 1600 K while the porosity reduction is found to be maximum at 1500 K. The infiltration kinetics is affected by the cohesion of the nanoparticles causing blockage of channels at higher operating temperatures. The simulation model is validated by comparing with the Lucas-Washburn infiltration model. It is seen that the simulation model deviates from the theoretical prediction suggesting that multiple mechanisms are driving the infiltration process at the nanoscale.
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Borom, Marcus P., Curtis A. Johnson et Louis A. Peluso. « Role of Environmental Deposits in Spallation of Thermal Barrier Coatings on Aeroengine and Land-Based Gas Turbine Hardware ». Dans ASME 1996 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-gt-285.
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Thermal barrier coating (TBC) spallation on power generation combustors was compared with TBC spallation observed both in military turboshaft engines, and in commercial turboprop engines. In each case, irrespective of operating conditions or geographic location, spallation was linked to the presence and infiltration of high temperature molten phases of similar composition. Electron microprobe analysis found that, from all the possible oxides available in the external environment, only CaO, MgO, Al2O3 and SiO2 (CMAS) are incorporated in the molten phase that infiltrates the TBC microstructure. Iron and nickel oxides from turbine components and zirconia and yttria from the TBC were also found in varying amounts in the molten phase. Melting of environmental deposits in conjunction with infiltration was found to result in: densification of the TBC, an increase in its Young’s modulus and an increase in the room temperature compressive stress in the TBC. Delamination of the TBC during thermal cycling is, thereby, attributed to changes in the mechanical properties and associated changes in the stress state of the coating due to infiltration of the environmental deposit.
Rapports d'organisations sur le sujet "Infiltrato"
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Andre Unger et Gudmundur Bodvarsson Ardyth Simmons. Simulating Infiltration at the Large-Scale Ponded Infiltration Test, INEEL. Office of Scientific and Technical Information (OSTI), mai 2001. http://dx.doi.org/10.2172/786550.
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Shillito, Rose, Markus Berli et Teamrat Ghezzehei. Quantifying the effect of subcritical water repellency on sorptivity : a physically based model. Engineer Research and Development Center (U.S.), juillet 2021. http://dx.doi.org/10.21079/11681/41054.
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Soil water wettability or water repellency is a phenomenon that can affect infiltration and, ultimately, runoff. Thus, there is a need to develop a model that can quantitatively capture the influence of water repellency on infiltration in a physically meaningful way and within the framework of existing infiltration theory. The analytical model developed in this study relates soil sorptivity (an infiltration parameter) with contact angle (a direct measure of water repellency) for variably saturated media. The model was validated with laboratory experiments using a silica sand of known properties treated to produce controlled degrees of water repellency. The measured contact angle and sorptivity values closely matched the model‐predicted values. Further, the relationship between the frequently used water drop penetration time test (used to assess water repellency) and sorptivity was illustrated. Finally, the direct impact of water repellency on saturated hydraulic conductivity was investigated due to its role in infiltration equations and to shed light on inconsistent field observations. It was found that water repellency had minimal effect on the saturated hydraulic conductivity of structureless sand. A quantitative model for infiltration incorporating the effect of water repellency is particularly important for post‐fire hydrologic modeling of burned areas exhibiting water repellent soils.
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McCurley, R. Analysis of Infiltration Uncertainty. Office of Scientific and Technical Information (OSTI), octobre 2003. http://dx.doi.org/10.2172/836530.
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Ng, Lisa. Implementing NIST infiltration correlations. Gaithersburg, MD : National Institute of Standards and Technology, 2022. http://dx.doi.org/10.6028/nist.tn.2221.
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Starr, T. L. Modeling of chemical vapor infiltration. Office of Scientific and Technical Information (OSTI), février 1989. http://dx.doi.org/10.2172/6408754.
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Pacira. Bilateral Tap Infiltration of EXPAREL. Touch Surgery Simulations, 2017. http://dx.doi.org/10.18556/touchsurgery/2017.s0115.
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Phifer, M. A. Engineered Trench #3 Infiltration Estimates. Office of Scientific and Technical Information (OSTI), décembre 2012. http://dx.doi.org/10.2172/1057752.
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Devlin, D. J. Microwave assisted chemical vapor infiltration. Office of Scientific and Technical Information (OSTI), décembre 1993. http://dx.doi.org/10.2172/10112511.
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Hurst, T., S. Tyler et J. Hess. Red Canyon wash infiltration studies. Office of Scientific and Technical Information (OSTI), septembre 1990. http://dx.doi.org/10.2172/6602739.
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Agassi, Menahem, Michael J. Singer, Eyal Ben-Dor, Naftaly Goldshleger, Donald Rundquist, Dan Blumberg et Yoram Benyamini. Developing Remote Sensing Based-Techniques for the Evaluation of Soil Infiltration Rate and Surface Roughness. United States Department of Agriculture, novembre 2001. http://dx.doi.org/10.32747/2001.7586479.bard.
Texte intégralRésumé :
The objective of this one-year project was to show whether a significant correlation can be established between the decreasing infiltration rate of the soil, during simulated rainstorm, and a following increase in the reflectance of the crusting soil. The project was supposed to be conducted under laboratory conditions, using at least three types of soils from each country. The general goal of this work was to develop a method for measuring the soil infiltration rate in-situ, solely from the reflectance readings, using a spectrometer. Loss of rain and irrigation water from cultivated fields is a matter of great concern, especially in arid, semi-arid regions, e.g. much of Israel and vast area in US, where water is a limiting factor for crop production. A major reason for runoff of rain and overhead irrigation water is the structural crust that is generated over a bare soils surface during rainfall or overhead irrigation events and reduces its infiltration rate (IR), considerably. IR data is essential for predicting the amount of percolating rainwater and runoff. Available information on in situ infiltration rate and crust strength is necessary for the farmers to consider: when it is necessary to cultivate for breaking the soil crust, crust strength and seedlings emergence, precision farming, etc. To date, soil IR is measured in the laboratory and in small-scale field plots, using rainfall simulators. This method is tedious and consumes considerable resources. Therefore, an available, non-destructive-in situ methods for soil IR and soil crusting levels evaluations, are essential for the verification of infiltration and runoff models and the evaluation of the amount of available water in the soil. In this research, soil samples from the US and Israel were subjected to simulated rainstorms of increasing levels of cumulative energies, during which IR (crusting levels) were measured. The soils from the US were studied simultaneously in the US and in Israel in order to compare the effect of the methodology on the results. The soil surface reflectance was remotely measured, using laboratory and portable spectrometers in the VIS-NIR and SWIR spectral region (0.4-2.5mm). A correlation coefficient spectra in which the wavelength, consisting of the higher correlation, was selected to hold the highest linear correlation between the spectroscopy and the infiltration rate. There does not appear to be a single wavelength that will be best for all soils. The results with the six soils in both countries indeed showed that there is a significant correlation between the infiltration rate of crusted soils and their reflectance values. Regarding the wavelength with the highest correlation for each soil, it is likely that either a combined analysis with more then one wavelength or several "best" wavelengths will be found that will provide useful data on soil surface condition and infiltration rate. The product of this work will serve as a model for predicting infiltration rate and crusting levels solely from the reflectance readings. Developing the aforementioned methodologies will allow increased utilization of rain and irrigation water, reduced runoff, floods and soil erosion hazards, reduced seedlings emergence problems and increased plants stand and yields.