Littérature scientifique sur le sujet « SWELLING NATURE »
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Articles de revues sur le sujet "SWELLING NATURE"
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Jayawardane, NS, et EL Greacen. « The nature of swelling in soils ». Soil Research 25, no 1 (1987) : 107. http://dx.doi.org/10.1071/sr9870107.
Texte intégralRésumé :
While existing swelling models adequately describe the swelling in extensively-swelling soils, their applicability to moderately-swelling soils has not been previously tested. The swelling of different layers of a transitional red-brown earth measured in situ using swelling gauges could not be described using existing swelling models. Values of �, defined as the ratio of change in bulk volume of the soil to change in gravimetric moisture content, were less than 0.33 over the whole of the measured moisture range in all layers of this soil, except the 0.25-0.55 m depth. This indicates that the extent of swelling was less than the normal, three-dimensional swelling described by existing models. Modifications to these existing models are proposed to describe the swelling in soils with moderate swelling characteristics. The compressibility factor (�), defined as the ratio of the change in void ratio to the change in moisture ratio, measures the same soil property as the values. Values of � determined in previous field studies and on soil cores of several clay soils are also less than the 0.33 specified for normal swelling, in keeping with the expectations of the modified swelling model. However, the need for further field testing of this model for moderately-swelling soils is emphasized. The limitations of existing methods for determining swelling characteristics of soils using core samples are discussed and several alternative procedures for in situ measurements are suggested.
2
Bihani, Ameya, et Jyoti P. Dabholkar. « Cystic schwannoma of cervical sympathetic chain masquerading as type II second branchial cleft cyst ». International Journal of Otorhinolaryngology and Head and Neck Surgery 1, no 1 (4 juillet 2015) : 45. http://dx.doi.org/10.18203/issn.2454-5929.ijohns20150588.
Texte intégralRésumé :
<p class="abstract"><span lang="EN-US">Brachial cleft cyst is the most common differential diagnosis of benign lateral neck swelling but other cystic swellings like carotid body tumours and cystic schwannomas should be kept in mind. MRI of neck is of great assistance in determining the nature of the swelling as fine needle aspiration cytology will fail in diagnosing such swellings accurately. We present a case of 22 year old female who presented with a slow growing swelling which was diagnosed as brachial cyst on FNAC and CT but turned out to be cystic schwannoma of cervical sympathetic chain which highlights the importance of considering various differentials of lateral neck swelling and limitation of FNAC and importance of pre-operative MRI in such cases.</span></p>
3
Blau, J. N., et F. Solomon. « MIGRAINE AND INTRACRANIAL SWELLING : AN EXPERIMENT OF NATURE ». Lancet 326, no 8457 (septembre 1985) : 718. http://dx.doi.org/10.1016/s0140-6736(85)92949-6.
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4
Shrestha, Sujan, Dinesh Khadka et Sujita Bhandari. « Head and Neck Swelling : A Cytopathological Perspective in a Hospital Based Study. » Birat Journal of Health Sciences 6, no 2 (3 novembre 2021) : 1460–65. http://dx.doi.org/10.3126/bjhs.v6i2.40319.
Texte intégralRésumé :
Introduction: Fine Needle Aspiration Cytology is a simple, relatively less painful, cost-effective minimal invasive procedure commonly employed in the evaluation of head and neck swellings. There are limited studies on cytological findings of head and neck swelling in Nepal. Objectives: The objective of this study was to study cytological findings of head and neck swellings. This study further intends to classify the nature of the swelling and use standardized international reporting system wherever required. Methodology: This is a retrospective hospital-based study done in the Department of Pathology at the Helping Hands Community Hospital, Kathmandu between 1 January 2019 and 32 December 2019. Slides of all FNAC from head and neck swelling done during this period was retrieved and evaluated for the study. Chi-Squared (χ2) test was used to investigate the significance of epidemiological and cytological parameters. Results: Males (56%) had more head and neck swelling than females (44%). The younger age group of less than twenty-five (< 25) years had more frequency of head and swelling followed by the older age group of more than fifty (>50) years. The most common site for Fine needle aspiration was lymph nodes (58%) followed by thyroid swelling (23%). Salivary gland swellings were the least frequent (5%). Of all the swelling, 17% of cases were attributed to malignant causes. Infective/Inflammatory causes (55%) were the most common cause of lymph node swellings. Metastatic carcinoma was more prevalent in the older age group of more than fifty (>50) years with a prevalence of 21% of total cases studies. Most of the thyroid swellings were found to be benign (58%) whereas 16% of thyroid swellings belonged to the malignant category. The total numbers of salivary gland swelling were the least with 55% of cases having benign neoplastic etiology. Diagnosis of developmental anomalies like a thyroglossal cyst, lymphangioma, branchial cyst, though relatively less common (10%) were also made with the help of cytologic studies. Conclusion: Fine Needle Aspiration is a useful method to differentiate benign and infective cases of head and neck swelling from neoplastic cases.
5
Ravishankar, M. V., N. M. Shama Sundar et Pushpalatha K. « Giant Papilloma on the Back of the Knee Joint - A Case Report ». Journal of Evolution of Medical and Dental Sciences 10, no 31 (2 août 2021) : 2517–20. http://dx.doi.org/10.14260/jemds/2021/515.
Texte intégralRésumé :
Papilloma is a benign tumour projecting above the surface of the skin. It grows from the epithelial tissue; develops as finger like fronds. Human contact with human papilloma virus (HPV) is one of the important causes for its occurrence. It feels rubbery and semisolid in consistency. Papilloma is a slow growing and long-lasting common tumor seen in various parts of the body like skin, breast, cervix, conjunctiva, etc. Its location on the exposed parts of the body like, around the face, neck, limbs, etc. causes much discomfort. Hence most of them prefer an early medical and surgical intervention to restore the cosmetic profile of the body to avoid growing physiopsychological discomforts. Clinical resemblance of any such swellings may require a meticulous examination and evaluation to differentiate them from other commonly seen external growths from the body surface; like sebaceous cyst, dermoid cyst, wart, haemangioma, neurofibroma, etc. One such clinical rare case of unusually large papilloma in an elderly lady aged about 65 years was presented with a swelling in her left popliteal region and excised under local anaesthesia, will be presented along with discussions. Human body is prone to show some solitary or multiple swellings on the inner or outer surface of the body. For the clinical diagnosis of a swelling, it is important for a clinician to know its source of origin. Swellings may arise from the skin, subcutaneous tissue, muscle, vessel, nerve, bone, etc. It is also important to consider whether it is a congenital or acquired defect or it is caused due to any trauma, or could be a mere inflammatory response which lasts temporarily.1 An abnormal growth of cells which grow more rapidly than other normal cells in the body are called neoplasms. They may be benign (harmless) or malignant (cancerous). Benign swellings are usually localized, may grow big without spreading or invading into other structures whereas malignant swellings can spread and invade the nearby tissues directly or through the blood or lymph nodes to different organs through metastasis, hence they need a thorough clinical evaluation. Soft tissue swelling especially in the young individuals often may be missed or delayed in the diagnosis of malignancy due to asymptomatic nature of the lesion with unfamiliar age. The nature of the swelling, its duration, location, and tissue of origin also matters in the final diagnosis. Hence it is important to differentiate a benign swelling from a malignant swelling at the earliest. 2
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S., Gangadhara K., Chaitanya Vadva et Sridhara S. « Comparative study of fine needle aspiration cytology and histopathology of thyroid swellings in tertiary health centre ». International Journal of Otorhinolaryngology and Head and Neck Surgery 8, no 1 (23 décembre 2021) : 53. http://dx.doi.org/10.18203/issn.2454-5929.ijohns20214900.
Texte intégralRésumé :
<p><strong>Background: </strong>Thyroid swelling being the most common presentation in ENT clinical practice, a prospective study was done to assess the role of Fine needle aspiration cytology in diagnosing the nature of thyroid swellings and comparing its results with histopathological examination findings.<strong></strong></p><p><strong>Methods: </strong>This is a prospective institutional based study comparing cytology and corresponding histopathology findings reported in 60 cases of thyroid swelling. The statistical analysis included sensitivity, specificity, positive predictive value, negative predictive value and accuracy in thyroid swelling.<strong></strong></p><p><strong>Results: </strong>Out of 60 cases, FNAC showed 93.3% and 6.6% of benign and malignant cases respectively whereas HPE showed 86.7% and 13.3% of benign and malignant cases respectively. On FNAC-HPE correlation using HPE as standard reference the diagnostic accuracy of present study is 91.66%.<strong></strong></p><p><strong>Conclusions: </strong>It was observed that FNAC is a reliable tool, safe and accurate method in evaluating thyroid swelling thus having great influences in treatment decision. Thus FNAC is the investigation of choice in thyroid swellings with excellent patient compliance, simple, safe and cost effective.<strong></strong></p>
7
Islam, Md Zahidul, Md Abdur Rahman et Md Sirajul Islam Mahfuz. « Congenital Anomalies Presenting as Head-Neck Swellings : A Study of 50 Cases ». Bangladesh Journal of Otorhinolaryngology 23, no 2 (27 janvier 2020) : 171–79. http://dx.doi.org/10.3329/bjo.v23i2.45164.
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Purpose: To analyse the prevalence, distribution and presentation of different congenital head-neck lesions with their age, sex, site and side predilection.
Methods: 50 patients of head-neck congenital swelling was selected from january/2013 upto december/2013 in the OPD of otorhino-laryngology, head and neck deptt. of Dhaka medical college hospital under a specific prospective study protocol.
Results: The most frequent swelling was thyroglossal cyst(42%), followed by branchial arch anomalies (18%),dermoid cyst(14%),pre-auricular sinus(14%),lymphangioma(8%) and haemangioma(4%).Amongst the cervical swellings the sequential preponderence was thyroglossal cyst(52%),branchial arch anomalies(23%),dermoid cyst(13%), lymphangioma(10%) and haemangioma (2%).The majority of branchial arch anomalies(100%) were of second arch. The majority of patients were of first(52%) and second(30%) decade and the male to female ratio for thyroglossal cysts was 1:1.1.The majority of lesions were painless swelling and all were surgically excised.
Conclusion: The overall frequency and age-sex distribution of congenital head-neck swellings as well as site, nature and type specific predominance of some of them in OPD of Dhaka medical college hospital are almost similar to international findings.
Bangladesh J Otorhinolaryngol; October 2017; 23(2): 171-179
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Chauhan, Ghanshyam S., et Swati Mahajan. « Structural aspects and nature of swelling medium as equilibrium swelling determinants of acrylamide and cellulosic-based smart hydrogels ». Journal of Applied Polymer Science 85, no 6 (24 mai 2002) : 1161–69. http://dx.doi.org/10.1002/app.10721.
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Kh Tursunova, G., K. h. R Karimov, K. h. T Trobov et D. j. A Rakhmanov. « CALCULATION OF THE GIBBS ENERGY OF WATER SORPTION ON SWELLING OF POLYMER GELS IN VARIOUS SOLUTIONS ». 2022-yil, 3-son (133/1) ANIQ FANLAR SERIYASI 1, no 131/2 (22 février 2022) : 1–9. http://dx.doi.org/10.59251/2181-1296.v1.1312.112.
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The effect of the nature and concentration of solutions of various metals, the nature of co-ions, the amount of cross-links, and the activity of water on the swelling of gels based on polystyrene and divinylbenzene in solutions of these compounds has been studied. Using the osmotic coefficients of these electrolytes on the basis of the experimental results, the change in the Gibbs energy of the swelling process was calculated.
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Makitra, R. G., et D. V. Bryk. « Effect of the nature of solvents on the swelling of coals ». Solid Fuel Chemistry 44, no 3 (juin 2010) : 164–68. http://dx.doi.org/10.3103/s0361521910030031.
Texte intégralThèses sur le sujet "SWELLING NATURE"
1
Sterner, Olof. « Swelling and protein adsorption characteristics of stimuli-responsive hydrogel gradients ». Thesis, Linköping University, Department of Physics, Chemistry and Biology, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-58586.
Texte intégralRésumé :
In this work, a gradient of interpenetrating polymer networks, consisting of anionic
and cationic polymers, has been investigated with respect to protein resistant
properties and swelling characteristics at different pH and ionic strength
conditions.
The swelling and protein adsorption have been studied using in situ spectroscopic
ellipsometry(SE) and imaging surface plasmon resonance(iSPR) respectively.
It has been shown that, by altering the buffer pH, the region of lowest
protein adsorption on the surface could be moved laterally. The swelling has
similarly been shown to respond to both changes in pH and ionic strength. Additionally,
the arise of surface charge and the polymer swelling in solution, both a
consequence of the ionisation of fixed charges on the polymer, have been indicated
to occur at different buffer pH.
The studied polymer systems show promising properties for future applications
in, for example, the biosensor area, where the surface chemistry can be
tailor-made to work optimally in a given environment.
2
Bhuana, Krishna Surya. « A study of extrudate swelling and melt fracture of natural rubber blends with EPDM and SBR ». Thesis, Loughborough University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394889.
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Ruffini, Andrea. « Preparazione di water swelling elastomers innovativi : analisi dell'effetto sinergico tra filler organici ed inorganici ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13417/.
Texte intégralRésumé :
È stata realizzata, ottimizzata e caratterizzata una mescola innovativa Water Swelling Elastomer (WSE) a base di gomma narurale - gomma SBR che fornisse il maggior rigonfiamento possibile cercando di mantenere buone proprietà meccaniche e stabilità strutturali. La caratterizzazione effettuata sulle diverse mescole realizzate ha permesso di individuare come i singoli componenti della formulazione influenzassero le prestazioni finali, come l’interazione sinergica tra filler organici (idrogel) e inorganici (bentonite) migliorasse le capacità di assorbimento dei campioni, e come l’utilizzo di agenti compatibilizzanti (silani e cere) migliorassero l’interazione fra i vari componenti della formulazione.
It was realized, optimized and characterized a new innovative Water Swelling Elastomer (WSE) compound based on natural rubber – SBR rubber. which would provide the greatest swelling degree, trying to maintain the best mechanical properties and structural stability. The characterization performed on different compounds allowed to identify how the components of the formulation would influence the final performance, how the synergy interaction of organic filler (hydrogel) and inorganic (bentonite) would improve the absorption capacity of the samples, and how the use of compatibilizing agents (silanes and waxes) would improve the interaction between the components of the formulation.
4
Guiducci, Lorenzo. « Passive biomimetic actuators : the role of material architecture ». Phd thesis, Universität Potsdam, 2013. http://opus.kobv.de/ubp/volltexte/2014/7044/.
Texte intégralRésumé :
Passive plant actuators have fascinated many researchers in the field of botany and structural biology since at least one century. Up to date, the most investigated tissue types in plant and artificial passive actuators are fibre-reinforced composites (and multilayered assemblies thereof) where stiff, almost inextensible cellulose microfibrils direct the otherwise isotropic swelling of a matrix. In addition, Nature provides examples of actuating systems based on lignified, low-swelling, cellular solids enclosing a high-swelling cellulosic phase. This is the case of the Delosperma nakurense seed capsule, in which a specialized tissue promotes the reversible opening of the capsule upon wetting. This tissue has a diamond-shaped honeycomb microstructure characterized by high geometrical anisotropy: when the cellulosic phase swells inside this constraining structure, the tissue deforms up to four times in one principal direction while maintaining its original dimension in the other.
Inspired by the example of the Delosoperma nakurense, in this thesis we analyze the role of architecture of 2D cellular solids as models for natural hygromorphs. To start off, we consider a simple fluid pressure acting in the cells and try to assess the influence of several architectural parameters onto their mechanical actuation. Since internal pressurization is a configurational type of load (that is the load direction is not fixed but it “follows” the structure as it deforms) it will result in the cellular structure acquiring a “spontaneous” shape. This shape is independent of the load but just depends on the architectural characteristics of the cells making up the structure itself. Whereas regular convex tiled cellular solids (such as hexagonal, triangular or square lattices) deform isotropically upon pressurization, we show through finite element simulations that by introducing anisotropic and non-convex, reentrant tiling large expansions can be achieved in each individual cell.
The influence of geometrical anisotropy onto the expansion behaviour of a diamond shaped honeycomb is assessed by FEM calculations and a Born lattice approximation. We found that anisotropic expansions (eigenstrains) comparable to those observed in the keels tissue of the Delosoperma nakurense are possible. In particular these depend on the relative contributions of bending and stretching of the beams building up the honeycomb.
Moreover, by varying the walls’ Young modulus E and internal pressure p we found that both the eigenstrains and 2D elastic moduli scale with the ratio p/E. Therefore the potential of these pressurized structures as soft actuators is outlined.
This approach was extended by considering several 2D cellular solids based on two types of non-convex cells. Each honeycomb is build as a lattice made of only one non-convex cell. Compared to usual honeycombs, these lattices have kinked walls between neighbouring cells which offers a hidden length scale allowing large directed deformations. By comparing the area expansion in all lattices, we were able to show that less convex cells are prone to achieve larger area expansions, but the direction in which the material expands is variable and depends on the local cell’s connectivity. This has repercussions both at the macroscopic (lattice level) and microscopic (cells level) scales. At the macroscopic scale, these non-convex lattices can experience large anisotropic (similarly to the diamond shaped honeycomb) or perfectly isotropic principal expansions, large shearing deformations or a mixed behaviour. Moreover, lattices that at the macroscopic scale expand similarly can show quite different microscopic deformation patterns that include zig-zag motions and radical changes of the initial cell shape. Depending on the lattice architecture, the microscopic deformations of the individual cells can be equal or not, so that they can build up or mutually compensate and hence give rise to the aforementioned variety of macroscopic behaviours. Interestingly, simple geometrical arguments involving the undeformed cell shape and its local connectivity enable to predict the results of the FE simulations.
Motivated by the results of the simulations, we also created experimental 3D printed models of such actuating structures. When swollen, the models undergo substantial deformation with deformation patterns qualitatively following those predicted by the simulations.
This work highlights how the internal architecture of a swellable cellular solid can lead to complex shape changes which may be useful in the fields of soft robotics or morphing structures.Passive pflanzliche Aktuatoren sind bewegliche Strukturen, die eine komplexe Bewegung ohne jegliche metabolische Energiequelle erzeugen können. Diese Fähigkeit entstammt dabei der Materialverteilung mit unterschiedlicher Quellbarkeit innerhalb der Gewebsstruktur.Die bis heute am besten untersuchten Gewebearten pflanzlicher und künstlicher Passivaktuatoren sind Faserverbundwerkstoffe, in denen steife, fast undehnbare Zellulosemikrofibrillen die ansonsten isotrope Schwellung einer Matrix leiten. Darüber hinaus gibt es in der Natur Beispiele für Aktuationssysteme, wie z.B. die Delosoperma nakurense Samenkapsel, in der das Aktuatorgewebe eine Wabenstruktur aufweist, deren Zellen mit einem hochquellenden Material gefüllt sind. Dabei hat die Wabenstruktur des Gewebes eine hohe geometrische Anisotropie, so dass sich das Gewebe bei Wasseraufnahme bis zur vierfachen Länge entlang einer Hauptrichtung ausdehnt und somit die reversible Öffnung der Kapsel angetrieben wird. Inspiriert durch das Vorbild der Delosoperma nakurense, wird in der vorliegenden Arbeit die Rolle der Architektur von 2D-Zellulärmaterialien als Modell für natürliche passive Aktuatoren analysiert. Zunächst wird anhand eines einfachen Flüssigkeitsdrucks in den Zellen der Einfluss verschiedener architektonischer Parameter auf deren mechanische Betätigung untersucht. Wohingegen regelmäßige konvexe Wabenstrukturen (wie z. B. sechseckige, dreieckige oder quadratische Gitter) sich unter Druck isotropisch verformen, wird durch Finite-Elemente-Simulationen gezeigt, dass es bei anisotropen und nicht-konvexen Zellen zu großen Ausdehnungen jeder einzelnen Zelle kommt. Auch wenn nur eine einzelne Zellgeometrie betrachtet wird, können hierbei viele verschiedene Gitter entstehen. Die Ausdehnungsrichtung des Gitters ist variabel und hängt von der lokalen Konnektivität der Zellen ab. Dies hat Auswirkungen sowohl auf makroskopischer (Gitter-) als auch auf mikroskopischer (Zell-) Ebene. Auf makroskopischer Ebene erfahren diese nicht-konvexen Gitter entweder große anisotrope (ähnlich der Delosperma nakurense Samenkapsel) oder vollkommen isotrope Eigendehnungen, große Scherverformungen oder jeweilige Mischformen. Überdies können Gitter mit ähnlichem makroskopischem Verhalten gänzlich unterschiedliche mikroskopische Verformungsmuster zeigen, wie z.B. Zick-Zack-Bewegungen oder radikale Änderungen der ursprünglichen Zellform. Dies verursacht auch eine entsprechende Änderung der elastischen Eigenschaften. In Abhängigkeit der Gitterarchitektur kann es zu gleichen oder unterschiedlichen mikroskopischen Zelldeformationen kommen, die sich in Summe entweder verstärken oder ausgleichen, und somit die Vielzahl an makroskopischen Verhalten erklären. Interessanterweise lassen sich mit Hilfe einfacher geometrischer Argumente aus der nichtdeformierten Zellform und Zellkonnektivität die Ergebnisse der FE-Simulationen vorhersagen. Die Ergebnisse der Finite-Elemente-Simulationen wurden durch Laborversuche bestätigt, in denen (mit 3D-Drucktechnik gefertigte) Modellgitter ähnliches Ausdehnungsverhalten beim Quellen zeigen. Diese Arbeit zeigt auf, wie die Innenarchitektur eines quellfähigen zellulären Feststoffs zu komplexen Formänderungen führen kann, die in den Bereichen der Soft-Robotik oder bei Morphing-Strukturen angewandt werden können.
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Nowamooz, Hossein. « RETRAIT/GONFLEMENT DES SOLS ARGILEUX COMPACTES ET NATURELS ». Phd thesis, Institut National Polytechnique de Lorraine - INPL, 2007. http://tel.archives-ouvertes.fr/tel-00331856.
Texte intégralRésumé :
Cette thèse rapporte les résultats d'études expérimentales effectuées à l'?domètre avec imposition de succion par la méthode osmotique sur des matériaux gonflants compactés lâches et naturels denses. Plusieurs cycles de séchage/humidification ont été appliqués sur ces matériaux sous trois faibles charges mécaniques constantes. Pendant ces cycles, les éprouvettes manifestent un retrait cumulé pour le sol lâche et un gonflement cumulé pour le sol dense. Les résultats montrent que dans les deux cas, les déformations volumiques convergent vers un état d'équilibre où le sol présente un comportement réversible. A la fin des cycles de succion, un cycle de chargement/déchargement a été effectué sous les succions constantes. Les valeurs de la pression de préconsolidation p0(s), de l'indice de compression vierge lambda(s) et de l'indice de compression élastique lambda dépendent directement des chemins de contrainte suivis.L'ensemble des résultats expérimentaux permet de déterminer les surfaces de charge : la limite de séparation de micro/macro (Lm/M) ; la surface de chargement-effondrement (LC) et la surface de comportement saturé (SCS). La succion limite entre la micro- et la macrostructure (Lm/M) dépend parfaitement de la structure interne et du diamètre qui délimite les deux familles de pores. L'évolution de la pression de préconsolidation en fonction de la succion imposée est présentée par la surface LC. Les courbes de compressibilité sous différentes succions convergent vers la courbe correspondant à l'état saturé sous de fortes contraintes appliquées. La pression à partir de laquelle, le sol continue son chemin sur la courbe du comportement normalement consolidé est appelée la pression de saturation (Psat). Plus la succion imposée est élevée, plus la charge nécessaire pour atteindre cette pression de saturation est importante. La surface SCS présente la variation de la pression de saturation en fonction de la succion imposée. Nous pouvons considérer que les surfaces de charge SCS et LC sont uniques pour les sols denses cependant elles se superposent à la fin des cycles de succion pour les sols lâches. Les cycles hydriques augmentent aussi la limite (Lm/M) entre la micro- et la macrostructure pour les deux sols.
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Halvarsson, Sören. « Manufacture of straw MDF and fibreboards ». Doctoral thesis, Mittuniversitetet, Institutionen för naturvetenskap, teknik och matematik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-11732.
Texte intégralRésumé :
The purpose of this thesis was to develop an economical, sustainable, and environmentally friendly straw Medium Density Fibreboard (MDF) process, capable of full-scale manufacturing and to produce MDF of requested quality. The investigated straw was based on wheat (Triticum aestivum L.) and rice (Oryzae sativa L.). In this thesis three different methods were taken for manufacture of straw MDF; (A) wheat-straw fibre was blowline blended with melamine-modified urea-formaldehyde (MUF), (B) rice-straw fibre was mixed with methylene diphenyl diisocyanate (MDI) in a resin drum-blender, and (C) wheat-straw fibre was activated in the blowline by the addition of Fenton’s reagent (H2O2/Fe2+) for production of non-resin MDF panels. The MUF/wheat straw MDF panels were approved according to the requirements of the EN standard for MDF (EN 622-5, 2006). The MDI/rice-straw MDF panels were approved according to requirements of the standard for MDF of the American National Standard Institute (ANSI A208.2-2002). The non-resin wheat-straw panels showed mediocre MDF panel properties and were not approved according to the requirements in the MDF standard. The dry process for wood-based MDF was modified for production of straw MDF. The straw MDF process was divided into seven main process steps. 1. Size-reduction (hammer-milling) and screening of straw 2. Wetting and heating of straw 3. Defibration 4. Resination of straw fibre 5. Mat forming 6. Pre-pressing 7. Hot-pressing The primary results were that the straw MDF process was capable of providing satisfactory straw MDF panels based on different types of straw species and adhesives. Moreover, the straw MDF process was performed in pilot-plant scale and demonstrated as a suitable method for producing straw MDF from straw bales to finished straw MDF panels. In the environmental perspective the agricultural straw-waste is a suitable source for producing MDF to avoid open field burning and to capture carbon dioxide (CO2), the biological sink for extended time into MDF panels, instead of converting straw directly into bio energy or applying straw fibre a few times as recycled paper. Additionally, the straw MDF panels can be recycled or converted to energy after utilization. A relationship between water retention value (WRV) of resinated straw fibres, the thickness swelling of corresponding straw MDF panels, and the amount of applied adhesive was determined. WRV of the straw fibre increased and the TS of straw MDF declined as a function of the resin content. The empirical models developed were of acceptable significance and the R2 values were 0.69 (WRV) and 0.75 (TS), respectively. Reduced thickness swelling of MDF as the resin content is increased is well-known. The increase of WRV as a function of added polymers is not completely established within the science of fibre swelling. Fortunately, more fundamental research can be initiated and likely a simple method for prediction of thickness swelling of MDF by analysis of the dried and resinated MDF fibres is possible.Syftet med denna avhandling var att lägga grunden för en ekonomisk, hållbar och miljövänlig MDF process för halmråvara, kapabel för fullskalig produktion av MDF och goda skivegenskaper. Framställningen av MDF skivor utgick från halm av vete (Triticum aestivum L.) och ris (Oryzae sativa L.). Tre olika metoder användes för att producera MDF av halm; (A) fibrer av vetehalm belimmades i blåsledning med ett melaminmodifierat urea-formaldehydlim (MUF), (B) fibrer av rishalm belimmades i en limblandare med metylen difenyl diisocyanate (MDI), (C) Limfria MDF skivor av vetehalm framställdes med aktivering av fibrer genom tillsats av Fenton´s reagens (H2O2/Fe2+) i blåsledning utan någon tillsats av syntetiskt lim. Sammanfattningsvis kan det understrykas att framställda MDF-skivor av MUF/vetehalm var godkända enligt standard för MDF (EN 622-5, 2006). Dessutom var framställda MDF skivor av MDI/rishalm också godkända enligt krav i standard för MDF ”American National Standard Institute” (ANSI A2008.2-2002). Limfria vetehalmskivor visade på måttliga skivegenskaper och klarade inte kraven i MDF standard. Fiberframställningsprocessen för MDF modifierades till en produktion utgående från halm. MDF processen för halm delades upp i sju primära processoperationer. (1) Storleksreducering och sållning av halm (2) Vätning och uppvärmning av halm (3) Defibrering (4) Belimning av halmfiber (5) Mattformning (6) Förpressning (7) Pressning De viktigaste resultaten från denna studie är att MDF av halm kunde produceras utgående från olika typer av halmsorter och lim. Dessutom utfördes MDF-processen i pilotskala och visade på en lämplig metod för framställning av MDF-skivor från halmbalar till färdiga halmfiberskivor. Det miljömässiga perspektivet på att använda jordbruksavfall till framställning av halmskivor är att undvika förbränning av halm ute på fältet, men det är även möjligt att binda koldioxid (CO2) i halmskivor under längre tid än att omsätta halmråvaran omedelbart som bioenergi eller använda halmfiber som returpapper några få gånger. Dessutom kan MDF återanvändas eller bli omsatt till energi efter användning. Ett förhållande mellan ”water retention value” (WRV), av belimmade halmfiber, tjocklekssvällning för motsvarande MDF av halmskivor och mängden av tillsatt lim vid olika nivåer har undersökts. Med ökande limhalt tilltog WRV fibersvällning, vidare minskade tjocklekssvällning för motsvarande MDF skivor. De framtagna empiriska modellerna var godtagbara och beräknade R2 värden var 0.69 (WRV) och 0.75 (TS). Minskad tjocklekssvällning med ökad limhalt är dokumenterad sen tidigare. Ökad fibersvällning WRV vid tillsats av polymerer (limmer) är inte fullständigt etablerad inom vetenskapen för fibersvällning. Lyckligtvis kan grundläggande forskning initieras och sannolikt föreligger en enkel metod för att prediktera tjocklekssvällning av MDF genom analyser av torkade och belimmad MDF fiber.
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Rouch, Matthias. « Contribution à la compréhension des mécanismes de vieillissement hydrothermique de matériaux composites unidirectionnels polyester insaturé/fibre de lin ». Thesis, Normandie, 2018. http://www.theses.fr/2018NORMC210/document.
Texte intégralRésumé :
De nombreux exemples de matériaux composites obtenus par l’association de fibres végétales et de polymères ont permis des allègements conséquents de structures dans divers domaines d’application. Cependant, la question demeure quant de la durabilité de ces pièces en service, essentiellement par manque de connaissances sur le vieillissement des fibres végétales, sur leurs interactions avec la matrice polymère et sur le comportement hydrothermique des composites biosourcés au cours du temps. Dans cette étude, nous avons étudié les cinétiques et mécanismes de sorption du matériau composite afin d’appréhender son comportement hydrique lors des vieillissements hydrothermiques par immersion dans l’eau à 23°C et 70°C. Cette étude a mis en évidence l’influence des fibres végétales sur les grandeurs caractéristiques de l’absorption en eau du matériau composite : forte prise en eau, gonflement anisotrope. Elle a également permis l’identification des mécanismes de dégradation des fibres de lin ; le rôle très nocif des résidus d’écorce rappelle l’importance du rouissage et du défibrage sur les performances de ces fibres. L’étude du comportement des constituants et du composite confrontés à des vieillissements hydrothermiques a ensuite été entreprise afin d’identifier et quantifier l’influence de chacun des matériaux constitutifs, ainsi que leur synergie. Il en ressort que la détérioration des fibres de lin est la principale cause de l’abattement des propriétés mécaniques du matériau composite. Si une immersion à 23°C pendant 70 jours n’a que peu d’effet sur les propriétés mécaniques, l’élévation de la température à 70°C induit des endommagements importants dès 14 jours d’immersion. La destruction des parois cellulaires et la dégradation des interfaces fibre/matrice sous l’effet de la présence d’eau détériorent le transfert de charge matrice/fibre. La corrélation entre les vieillissements accélérés et naturel a fait ressortir une similitude entre le maintien pendant 70 jours dans l’eau à 23°C et l’exposition aux conditions naturelles pendant 24 mois ; l’immersion à 70°C s’avère trop sévère. Une solution d’amélioration serait d’accentuer le rouissage des fibres afin de supprimer davantage les composés pectiques de la lamelle mitoyenne et de la paroi primaire. L’élimination de ces composés facilement hydrolysables par l’eau permettrait de prétendre à une meilleure qualité de l’interface fibres/matrice tout au long du vieillissementA great number of plant fiber – reinforced polymer composites allowed substantial lightening of structures in various fields of application. However, the question remains about the durability of these parts in service, mainly for lack of knowledge about the aging of plant fibers, their interactions with the polymer matrix and the hydrothermal behavior of biosourced composites over time. In this work, water absorption mechanisms and kinetics by the composite material are studied in order to understand the hydric behavior during hydrothermal aging by immersion in deionized water at 23°C or 70°C. The results show that water absorption by the composite is characterized by a high water uptake and an anisotropic swelling. It also allowed the identification of the degradation mechanisms of flax fibers; the very harmful role of bark residues recalls the importance of retting and decortication on the performance of these fibers.The investigation of the behaviors of the constituents and the composite under hydrothermal aging was then undertaken with the aim to identify and quantify the influence of each on the constituent materials, as well as their synergy. It shows that the deterioration of the flax fibers is the main cause of the reduction of the mechanical properties of the composite. If immersion at 23 ° C for 70 days has little effect on the mechanical properties, raising the temperature to 70 ° C induces significant damage from 14 days of immersion. The destruction of the cell walls and the degradation of the fiber/matrix interfaces due to water deteriorate the load transfer efficiency by the fiber/matrix interface. The correlation between accelerated and natural aging showed a similarity between holding for 70 days in water at 23 ° C and exposure to natural conditions for 24 months; immersion at 70 ° C is too severe. An improvement solution would be to increase the retting of the fibers in order to further remove the pectic compounds from the middle lamella and the primary wall. The elimination of these compounds easily hydrolysable by water would claim to a better quality of the fiber / matrix interface throughout aging
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Jin, Yao. « Procédés de séparation membranaire de colloïdes : caractérisation des mécanismes aux échelles nanométriques et intensification par ultrasons ». Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENI063/document.
Texte intégralRésumé :
Cette thèse étudie le procédé d’ultrafiltration tangentiel assisté par ultrasons aux échellesmacro et nanométriques. Différentes dispersions colloïdales ont été filtrées (argiles, micelle decaséine, nanocristaux d’amidon et de cellulose). Les propriétés d'écoulement et les changementsinduits par les ultrasons (US) ont été caractérisés. Les organisations structurelles à proximité de lamembrane ont été mises en évidence pour la première fois aux échelles nanométriques, lors de lafiltration par diffusion de rayons X aux petits angles in-situ. L’application des US a permis uneaugmentation significative des flux de perméation d’un facteur 1,6 à 13,5, selon l'organisationstructurale des colloïdes. Trois mécanismes induits par les US ont été identifiés : une érosioncomplète, une rupture partielle ou pas de changement (nanométrique) des couches de particulesaccumulées. Grâce aux profils de concentration obtenus, une approche de modélisation a permisune prévision du flux perméationThis thesis studies an ultrasonic assisted cross-flow ultrafiltration process from macro tonano scales. Different types of colloids were investigated: synthetic and natural clay dispersions,casein micelles (skim milk) and starch or cellulose nanocrystal suspensions. Firstly, flowproperties and the changes due to ultrasound (US) were investigated. Secondly, structuralorganizations at nanometer length scales in the vicinity of the membrane during filtration havebeen revealed for the first time by real-time in-situ Small Angle X-ray Scattering. The applied USincreased significantly the permeate flux of ultrafiltration by an enhancement factor of 1.6 to13.5, depending on the structural organization of the colloids. The applied US has led to threemain effects: a removal of accumulated particle layer, a partial disruption or no change of thenano-organization. Thirdly, thanks to the obtained concentration profiles, a modeling approachhas allowed a prediction of the permeate flux
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RALLI, ROHIT. « COMPARATIVE STUDY OF STABILIZATION OF EXPANSIVE SOIL USING MICROSILICA AND RICE HUSK ASH ». Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14924.
Texte intégralRésumé :
The engineering properties of expansive soils may need to be improved to make them suitable for construction using some sort of stabilization methods. Stabilization of pavement subgrade having expansive soils has traditionally relied on treatment with lime, cement, or waste materials such as microsilica. Most transportation agencies, however, are hesitant to specify these non-traditional stabilizers without reliable data to support vendor claims of product effectiveness. The main objective of this study is to investigate the effect of the engineering properties of expansive soils when blended with microsilica and Rice husk ash. Utilizing some of these materials as alternative materials for the construction in no doubt is a best solution. Hence an attempt is made to justify the use of microsilica and RHA for stabilization of expansive soil. This paper highlights the effectiveness of using these materials in the treatment of soil. Laboratory test results presents the influence of different mix proportions of microsilica and rice husk ash on compaction, strength and swelling nature properties of soil.
Livres sur le sujet "SWELLING NATURE"
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B, Nuhfer Edward, et American Institute of Professional Geologists., dir. The Citizens' guide to geologic hazards : A guide to understanding geologic hazards, including asbestos, radon, swelling soils, earthquakes, volcanoes, landslides, subsidence, floods, and coastal hazards. Arvada, CO : The Institute, 1993.
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Steiner, Franz. Neues aus Anderwelt Nummer 31. Sous la direction de Ruth M. Fuchs et Freundeskreis Anderwelt. Karlsfeld, Germany : Freundeskreis Anderwelt, 2010.
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Stein, Friederike. Neues aus Anderwelt Nummer 38. Sous la direction de Ruth M. Fuchs et Freundeskreis Anderwelt. 2e éd. Karlsfeld, Germany : Freundeskreis Anderwelt, 2012.
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Weber, Tanja. Neues aus Anderwelt Nummer 35. Sous la direction de Ruth M. Fuchs et Freundeskreis Anderwelt. 2e éd. Karlsfeld, Germany : Freundeskreis Anderwelt, 2011.
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Fuchs, Dieter. Neues aus Anderwelt Nummer 33. Sous la direction de Ruth M. Fuchs. 3e éd. Karlsfeld, Germany : Freundeskreis Anderwelt, 2010.
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Fuchs, Ruth M. Neues aus Anderwelt Nummer 34. Karlsfeld, Germany : Freundeskreis Anderwelt, 2011.
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Gerstner, Michaela. Neues aus Anderwelt Nummer 32. Sous la direction de Ruth M. Fuchs. 2e éd. Karlsfeld, Germany : Freundeskreis Anderwelt, 2010.
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Nuhfer, Edward B., et Richard J. Proctor. The Citizens' Guide to Geologic Hazards : A Guide to Understanding Geologic Hazards Including Asbestos, Radon, Swelling Soils, Earthquakes, Volcanoes. Amer Inst of Professional, 1993.
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Neues aus Anderwelt Nummer 36. 3e éd. Karlsfeld (Germany) : Freundeskreis Anderwelt, 2011.
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Neues aus Anderwelt Nummer 37. Karlsfeld, Germany : Freundeskreis Anderwelt, 2012.
Trouver le texte intégralChapitres de livres sur le sujet "SWELLING NATURE"
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Kyokawa, H., M. Kikumoto et Y. Cui. « Constitutive model of expansive soft rock considering cementation and swelling nature ». Dans Smart Geotechnics for Smart Societies, 857–61. London : CRC Press, 2023. http://dx.doi.org/10.1201/9781003299127-117.
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Nsiah-Baafi, E., M. J. Tapas, K. Vessalas, P. Thomas et V. Sirivivatnanon. « Characterization of the Nano- and Microscale Deterioration Mechanism of the Alkali–Silica Reaction in Concrete Using Neutron and X-ray Scattering Techniques : A Review ». Dans Lecture Notes in Civil Engineering, 469–77. Singapore : Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-3330-3_47.
Texte intégralRésumé :
AbstractAlkali–silica reaction (ASR) is one of the most recognized chemical reactions that lead to the deterioration and premature failure of concrete. The severity of ASR is largely dependent on the expansive nature of the reaction product (ASR gel). As such, it is important to expound the developed knowledge on the formation, structure, composition, and swelling mechanism of ASR gel, to provide a greater understanding of ASR deterioration and to facilitate the development of more reliable prediction and mitigation methods. We present a summary of existing methods for assessing ASR and the state-of-the-art techniques that use neutron and X-ray scattering methods to characterize the nano- and microstructural properties of concrete and elucidate the potential transport dynamics of reactants that determine the mechanism and extent of ASR.
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Krishnan, Jayalakshmi. « TLRs in Lymphatic Filariasis ». Dans Toll-Like Receptors in Vector-borne Diseases, 26–30. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815124545123010006.
Texte intégralRésumé :
Lymphatic filariasis is one of the neglected tropical diseases and also a disfiguring vector-borne disease. Parasitic nematodes such as Wuchereriabancrofti, Brugiamalayi, and Brugiatimori are the three types of parasites that cause lymphatic pathology in terms of hydrocele, lymphedema, and elephantiasis [1]. Among these three parasites, Wuchereriabancrofti is the principal parasite, which causes around 90% of infections. These nematodes impair the lymphatic system, thus leading to considerable morbidity in the affected people. The life cycle of this adult-stage lymph-dwelling parasites is complex in nature. Once they start infecting the lymphatics, they cause swelling, dilatation, and thickening of lymph vessels.
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Clunie, Gavin, Nick Wilkinson, Elena Nikiphorou et Deepak R. Jadon. « Evaluating rheumatological and musculoskeletal symptoms ». Dans Oxford Handbook of Rheumatology, sous la direction de Gavin Clunie, Nick Wilkinson, Elena Nikiphorou et Deepak R. Jadon, 3–24. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198728252.003.0001.
Texte intégralRésumé :
General rheumatological assessment is for musculoskeletal pain, stiffness or swelling, weakness, fever, rashes, and fatigue. This chapter describes both the nature of those symptoms helpful in making a diagnosis and also the subjective elements influenced by exertion, loss of function, anxiety, cultural norms, and other symptoms. In children and adolescents, symptoms are also influenced by developmental stage and may present simply as a limp or loss of limb function. Other referrals are for symptom complexes (such as Raynaud’s disease) or isolated abnormal investigations (such as elevated erythrocyte sedimentation rate or antinuclear antibody). Both paediatric and adult assessment requires the effective use of the (p)GALS screening examination tool described here. The nature of symptoms requiring rheumatological assessment varies according to diagnosis and has a subjective element influenced by exertion, impact, anxiety, cultural norms, and associated symptoms. They include musculoskeletal pain and stiffness, weakness or loss of limb function, fever, and also fatigue. Other referrals require assessment of symptom complexes or isolated abnormal investigations.
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Bustamante-Torres, Moises, David Romero-Fierro, Bryan Chiguano-Tapia, Estefani Chichande-Proaño et Emilio Bucio. « Hydrogels and Nanohydrogels ». Dans Frontiers in Nanomedicine, 140–82. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815136920123030009.
Texte intégralRésumé :
Hydrogels and nanogels are exciting and promising materials for many applications due to their versatile features, such as interacting and absorbing a significant amount of water and other solvents, excellent mechanical properties, and adhesiveness. These materials are obtained based on the nature of the raw materials (natural or synthetic) and the synthesis route. There are many ways to synthesize hydrogels and nanogels; however, these routes can be classified as physical or chemical. Physical synthesis forms a reversible cross-linking. In contrast, chemical synthesis can generate a stable, rigid, and irreversible polymeric structure. Nowadays, the term “smart hydrogel” has gained significant attention due to its response to external factors, such as pH, temperature, light, electricity, and magnetic, and even an internal approach as substrate. Besides, the characteristics and properties of these polymeric matrices can be enhanced through the synergic relationship with nanoparticles. The inner and outer structure and the behavior of these materials can be studied through characterization techniques, such as light scattering, gel permeation chromatography, viscometry, thermal analysis, spectroscopies, microscopies, and swelling.
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« 1. Features of the state of bound water in Bio-Objects as an example of the nature of sorbed in swelling sorbents ». Dans Interface Science and Technology, 5–40. Elsevier, 2007. http://dx.doi.org/10.1016/s1573-4285(07)80004-4.
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Ur Rehman, Tanzil, Luqman Ali Shah, Noor Saeed Khattak, Abbas Khan, Noor Rehman et Sultan Alam. « Superabsorbent Hydrogels for Heavy Metal Removal ». Dans Trace Metals in the Environment - New Approaches and Recent Advances. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.89350.
Texte intégralRésumé :
The superabsorbent hydrogels (SAHs) are 3D polymer networks having hydrophilic nature, which can swell, absorb, and hold incredible amount of water in aqueous medium showing better sorption ability. The sorption ability enables SAH to absorb organic pollutants, dyes, and heavy metal ions (HMI) from wastewater. Therefore, SAHs have recently got considerable interest from the researchers to be used for wastewater treatment. In order to know the swelling property and to understand the wastewater treatment in general and heavy metal ion removal from industrial effluent in particular, this chapter describes the removal of heavy metal ions from wastewater in details. Thus this chapter will enable us to understand the theoretical and experimental part regarding the removal of heavy metal ions by SAH from wastewater. It also highlights the parameters of adsorption process such as effect of initial concentration of heavy metal ions, effect of external stimuli (pH), effect of temperature on the removal of heavy metal ions, and dosage studies. The synthesis of SAH and its use for removal of heavy metal ions from wastewater as well as recycling, selectivity, and effectiveness are also discussed in detail.
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Tuszewicki, Marek. « Diseases as Demonic Beings ». Dans A Frog Under the Tongue, 213–32. Liverpool University Press, 2021. http://dx.doi.org/10.3828/liverpool/9781906764982.003.0012.
Texte intégralRésumé :
This chapter discusses how Jews view diseases as manifestations of demons. The Jewish culture of eastern Europe saw diseases either as autonomous entities whose existence was closely bound up with that of humans or as entirely separate beings that could take possession of the human body and manifest themselves in the form of various symptoms (pain, stabbing sensations, swelling, redness, etc.). Some of these 'lived' in the body of their host as congenital to it, even vital for its proper functioning. Others were seen as harmful intruders. This anthropomorphization of physical misfortunes had a variety of consequences for therapeutic practices. The demonic character of diseases invading the human body occasioned the use of remedies designed to confuse, frighten away, disgust, bribe, or starve the anthropomorphized complaint. Diseases that were imagined as unclean beings would be treated with a vast arsenal of magical remedies, including popular apotropaics. In the popular conception the human body was the natural seat of all manner of beings, without which it could not exist. These were normally dormant, but in certain adverse conditions they would awake and make their presence painfully felt in some way. Jewish sources contain examples of magic incantations to drive out worms, conjurations in Yiddish borrowed from the language of the Christian environment, biblical quotes, and so on. In the folk understanding, it was in the nature of some diseases to 'attack' whole populations. Mystical methods were ubiquitously employed to combat plague, the most widespread being symbolic isolation.
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Pahuja, Sanuj, Rohit Prasad, Utkarsh Diwakar et Anil Kumar. « Synthesis of CMTKG Acrylamide-Urea Hydrogel and Its Application as a Fertilizer Delivery System ». Dans Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220746.
Texte intégralRésumé :
Nitrogen (N) is a macronutrient which is required for growth of plants. The most common way of providing nitrogen to the plants is through urea fertilizers. With the increasing demand for crops, the usage and demand of urea as a fertilizer has also been increasing. A lot of nitrogen that is supplied in form of fertilizers actually gets wasted. Almost 40–70 % nitrogen supplied through urea is not utilized by plants, generating environmental problems like eutrophication, therefore there is a need of developing a fertilizer that will stop this wastage. The aim of this study was to use natural products like CMTKG for preparing crosslinked Urea hydrogel which can be used as a fertilizer releasing agent. This work reports the synthesis of hydrogel using Carboxymethyl tamarind kernel gum (CMTKG) with Acrylamide (AAm), a solution of Sodium Hydroxide (NaOH), and Methacrylic acid (MA). The initiator used for this synthesis was Potassium persulfate (KPS), crosslinker was N, N-methylenebis (acrylamide) (MBA). The hydrogel synthesis was confirmed by characterization with swelling tests in a different pH solutions including pH 4, pH 7, pH 9, and distilled water. After the swelling studies of the hydrogel swelling index and swelling equilibrium were determined. The prepared hydrogel showed degradable properties in the soil burial test.
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Devaraj, Vikram. « Soft tissue swellings of the hand and upper limb ». Dans Oxford Textbook of Plastic and Reconstructive Surgery, sous la direction de Vivien Lees et James Haeney, 557–62. Oxford University Press, 2021. http://dx.doi.org/10.1093/med/9780199682874.003.0162.
Texte intégralRésumé :
There is a broad range of soft tissue swellings in the hand, and most are benign lesions. Depending on their nature, they can be managed non-surgically or by excision. Malignant lesions are rare and careful assessment of the patient at presentation with appropriate investigation will distinguish these lesions which may require a multimodal approach to treatment.
Actes de conférences sur le sujet "SWELLING NATURE"
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Melker, Alexander I. « On the nature of void swelling ». Dans Nano-Design, Technology, Computer Simulations, sous la direction de Alexander I. Melker et Vladislav V. Nelayev. SPIE, 2008. http://dx.doi.org/10.1117/12.836492.
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Markovic, Maja, Vesna Panic, Julijana Tadic et Rada Pjanovic. « EFFECT OF CROSSLINKER AMOUNT ON HYBRID HYDROGELS SWELLING AND DRUG RELEASE ». Dans 1st INTERNATIONAL Conference on Chemo and BioInformatics. Institute for Information Technologies, University of Kragujevac, 2021. http://dx.doi.org/10.46793/iccbi21.125m.
Texte intégralRésumé :
Targeted drug delivery is powerful tool which researchers use to achieve safer and more efficient therapy of many diseases, including various types of cancer. Many chemotherapeutics are poorly water- soluble, so their encapsulation and targeted delivery remain quite challenge. Hydrogels based on poly(methacrylic acid) (PMAA) are widely investigated for targeted drug delivery due to their pH sensitivity, non-toxicity and biocompatibility. Still, due to the PMAA highly hydrophilic nature, PMAA can only be used for encapsulation and targeted delivery of water-soluble drugs. Our previous research was directed towards overcoming this limitation: PMAA was modified with amphiphilic protein – casein and poorly-water soluble model drug – caffeine – was encapsulated (PMAC). Present study is focused on investigation how variation of amount of one of the most important hydrogels network parameter such as crosslinker affect PMAC swelling properties and caffeine release. The group of hybrid hydrogels – PMAC – was synthesized with various amount of crosslinker: 0.4mol%, 0.8mol%, 1.6mol% and 3.2mol% with respect to methacrylic acid. Swelling behavior of hybrid hydrogels and caffeine release was investigated in two environments which simulated human stomach and intestines. Obtained results showed that targeted delivery of poorly water-soluble model drug was achieved and that its release can be prolonged up to 24h. Also, kinetic of poorly water-soluble drug release can be easily modified only by changing crosslinker amount. PMAC hybrid hydrogels have huge potential for targeted delivery of poorly water-soluble active substances.
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Hulme, Paul, Sabina Bruehlmann et Neil A. Duncan. « Apparatus to Determine the Macroscopic and Microscopic Biaxial Swelling Response of the Annulus Fibrosus ». Dans ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-32506.
Texte intégralRésumé :
The intervertebral disc (IVD) is a “hydrostatic load-bearing structure” [1], found between the vertebral bodies of the spine. The IVD is composed of the inner and outer annulus fibrosus and a gelatinous center, the nucleus pulposus. Fluid is the largest component of the IVD. Swelling affects the macroscopic mechanical response of the tissue, as well as the microscopic nutrient and solute transport to the cells of the IVD. Previous studies describing the macroscopic swelling behaviour of the annulus fibrosus have been uniaxial in nature [2,3]. However, the behaviour of the annulus is markedly affected by its geometry [3]. By examining a biaxial section of annulus fibrosus with a portion of the bone attachment present, the structure of the annular test section will be maintained and by inference so should its function [4]. Therefore, the objective of this study was to develop an apparatus to investigate simultaneously both the macroscopic and microscopic swelling behaviour of the annulus fibrosus subjected to realistic biaxial loading. The biaxial loading device should maintain the annulus fibrosus in vivo geometry and environment, monitor stress and control tissue strain, while positioning the tissue in a manner that allows for in situ visualization of the cells.
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Fayazi, A., S. Maaref, S. Esmaeili et A. Kantzas. « Measurement of CO2 Solubility and Swelling Factor in Water/Brine for CO2 Sequestration ». Dans SPE Latin American and Caribbean Petroleum Engineering Conference. SPE, 2023. http://dx.doi.org/10.2118/213145-ms.
Texte intégralRésumé :
Abstract CO2 dissolution in water/brine at various operating conditions is of essential interest for various environmental and geochemical applications such as CO2 sequestration in brine-bearing aquifers. Solubility/swelling in CO2-brine systems can be determined by experimental data or the available correlations and modelling packages. However, the available models and correlations can only be used in limited situations, and therefore, may not be applicable for a wide range of operating conditions, particularly for different salinities. In addition, the available solubility and swelling experimental data in the literature are limited as these experiments are very time consuming due to the slow nature of the diffusion process. Therefore, reliable experimental data is needed especially in the range of operating conditions suitable for CO2 storage scenarios. In this work, a high-pressure high-temperature (HPHT) visual cell with a novel stirring mechanism was designed to accelerate the diffusion process at elevated pressures and temperatures. A series of swelling/solubility tests are carried out for a CO2–brine/water system at various equilibrium pressures ranging from ~ 3000 to ~ 12000 kPa and temperatures ranging from 35 to 55 °C and with different salinities. The process of CO2 dissolution results in a pressure decline and volume expansion (swelling) of the liquid phase over time. Swelling is measured by tracking the gas-liquid interface using a microscope camera and solubility is measured by monitoring the pressure and performing PVT analysis. In the absence of stirring, the CO2 dissolution takes a long time, however, the use of stirring expedites the dissolution process. Thermodynamically, we have an instantaneous equilibrium at the gas–liquid interface and the equilibrium concentration at the gas–liquid interface is the maximum concentration of dissolved gas (i.e., solubility) in the liquid. The diffusion which controls how quickly the gas dissolves in the liquid slows downs the overall process. The high-pressure stirring mechanism creates convection in the liquid and accelerates CO2 dissolution. The results also revealed that increasing the pressure, decreasing the temperature, and decreasing the brine salinity increases the swelling and solubility of CO2.
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Ivanishin, Igor, Bradley Abell et Hadi Nasrabadi. « Optimized X-Ray Diffraction Analysis Predicts the Swelling Potential of Shales ». Dans SPE Eastern Regional Meeting. SPE, 2022. http://dx.doi.org/10.2118/211879-ms.
Texte intégralRésumé :
Abstract The presence of expandable clay minerals within the reservoir and source rocks causes many issues over the life of the well. These include wellbore instability and increased mud losses during drilling operations, complications and decrease in production during and after hydraulic fracturing, etc. Existing standard laboratory test methods, e.g., capillary suction time test, do not adequately predict swelling potential. The present work provides the technique to determine the properties and quantify the concentration of expandable clay minerals, thus predicting the swelling potential of clay-rich rocks. A collection of ash layer and bentonite mine samples has been analyzed for the bulk and clay fraction mineral composition and swelling in completion fluids. Comparison of X-ray diffractograms recorded from air-dried and ethylene glycolated clay fractions of ash layer samples confirmed the absence of discrete smectite but revealed the presence of interstratified illite/smectite and illite. X-ray diffractograms of all the ethylene glycolated samples have characteristic complex reflections with two maximas: one between 6.8–7.8°2θ (11.3–13.1 Å), another between 9.3–9.6°2θ (9.3–9.5 Å). Both correspond to the 001 reflection of interstratified illite/smectite mineral, and not a pure endmember illite or smectite. Two properties of this mineral vary among the samples and influence their expandability: (1) illite:smectite ratio in the range 3:2–9:1, and (2) the nature of the interstratification, i.e., the degree of ordering. The shifts of the peak maximas in the regions 6.8–9.6°2θ and 42.0–48.0°2θ are used to calculate the proportion of the component layers. Proposed technique of optimized XRD analysis reveals that the samples containing less illite/smectite mineral, but the higher concentration of smectite layers in this mixed-layer mineral are more expandable. Optimized XRD analysis correctly predicts the swelling potential of a given clay-rich zone (e.g., ash layer) as confirmed by confined immersion testing. Provided technique of XRD analysis is fast, requires small quantities of sample, and could possibly be integrated to field logs in the future. Obtained knowledge can be applied by engineers and researchers working with shale formations around the world.
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Sadek, Samir Hassan, et Mehmet Yildiz. « Numerical Simulation of Die Swell of Second-Order Fluids Using Smoothed Particle Hydrodynamics ». Dans ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-39215.
Texte intégralRésumé :
This work presents the development of both weakly compressible and incompressible Smoothed Particle Hydrodynamics (SPH) models for simulating two-dimensional transient viscoelastic free surface flow which has extensive applications in polymer processing industries. As an illustration with industrial significance, we have chosen to model the extrudate swell of a second-order polymeric fluid. The extrudate or die swell is a phenomenon that takes place during the extrusion of polymeric fluids. When a polymeric fluid is forced through a die to give a polymer its desired shape, due to its viscoelastic non-Newtonian nature, it shows a tendency to swell or contract at the die exit depending on its rheological parameters. The die swell phenomenon is a typical example of a free surface problem where the free surface is formed at the die exit after the polymeric fluid has been extruded. The swelling process leads to an undesired increase in the dimensions of the extrudate. To be able to obtain a near-net shape product, the flow in the extrusion process should be well-understood to shed some light on the important process parameters behind the swelling phenomenon. To this end, a systematic study has been carried out to compare constitutive models proposed in literature for second-order fluids in terms of their ability to capture the physics behind the swelling phenomenon. The effect of various process and rheological parameters on the die swell such as the extrusion velocity, normal stress coefficients, and Reynolds and Deborah numbers have also been investigated. The models developed here can predict both swelling and contraction of the extrudate successfully. The die swell problem was solved for a wide range of Deborah numbers and for two different Re numbers. The numerical model was validated through the solution of fully developed Newtonian and Non-Newtonian viscoelastic flows in a two-dimensional channel, and the results of these two benchmark problems were compared with analytic solutions, and good agreements were obtained.
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Jackson, Alicia R., Tai-Yi Yuan, Chun-Yuh Huang et Wei Yong Gu. « A Two-Point Conductivity Approach to Measuring Fixed Charge Density in Intervertebral Disc Tissue ». Dans ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206310.
Texte intégralRésumé :
Low back pain, a major socio-economic concern in the United States, is believed to result from degeneration of the intervertebral disc (IVD) of the spine [1]. The IVD is characterized as a charged, hydrated soft tissue made up of a central nucleus pulposus (NP) surrounded by the layered annulus fibrosus (AF). The negatively-charged nature of the disc derives from the charged groups attached to the glycosaminoglycan (GAG) molecules found on proteoglycans (PG) in the extracellular matrix of the disc. The fixed charge density (FCD) is a measure of the number of negative charges attached to the disc matrix per unit volume. FCD is important to disc function, both mechanically (i.e., swelling pressure) and in terms of transport through the disc [2].
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Oliveira, Persis Araújo, Juliana Campelo Aragão Bitencourt et Lorena Natali Cardoso Fernandes Caldas. « DIAGNOSTIC CHALLENGE OF A LOCALLY ADVANCED LESION : CASE REPORT OF PRIMARY BREAST ANGIOSARCOMA ». Dans Scientifc papers of XXIII Brazilian Breast Congress - 2021. Mastology, 2021. http://dx.doi.org/10.29289/259453942021v31s1082.
Texte intégralRésumé :
Introduction: Primary angiosarcoma of the breast (PAOB) is a class of extremely rare sarcomas, with an incidence rate of 1/2,000 cases of breast cancer worldwide. It is more frequent in 20- and 50-year-old women without history of previous cancer and commonly described in the left breast. Clinical presentation can be the same as usual breast cancer and histology can mimic poorly differentiated ductal carcinoma, which is why immunohistochemistry should be performed. Swelling, a feeling of fullness and exponential growth within the breast are frequent complaints, as noted by Kunkiel et al. in their series of case reports. The natural history of PAOB is only partly understood, suggesting that the lesion begins within the mammary parenchyma and then infiltrates skin and subcutaneous tissue nearby. The predominant management has been mastectomy, mainly, or sectorectomy with clear margins in cases of conservative breast surgery. Adjuvant therapies are not associated with improved survival, except for adjuvant chemotherapy in localized tumors of 5 cm or more. Case report: S.O.S., a 32-year-old woman, identified breast asymmetry in 2017, during the lactation period, presence of mild pain and swelling in the left breast. She was admitted to the breast cancer and benign lesions outpatient clinic at Professor Alberto Antunes University Hospital in February 2019. She held a BI-RADS 4 breast magnetic resonance imaging (MRI) in January 2019, which suggestedan irregular mass in the left breast, probably of vasculolymphatic nature; also showed core biopsy in February 2019: low-grade PAOB. In April 2019, she underwent a modified radical mastectomy of the left breast with ipsilateral lymphadenectomy. Due to the large extent of the lesion, an entire cutaneous area of left anterior hemithorax was resected, and thoracoepigastric flap was used to close the left hemithorax. An anatomopathological report diagnosed PAOB grade I. In July 2019, immunohistochemistry corroborated the diagnosis of PAOB with CD31 positive; positive von Willebrand factor (Factor VIII - polyclonal Rabbit) and ki67 positive for 25% of neoplastic cells. In the fourth month after the surgery, the patient started adjuvant radiotherapy, concluding it in October 2019. In post-treatment follow-up, in January 2021, she was referred to the breast reconstruction program, awaiting the procedure until this report was made.
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Santra, Ashok, Hasmukh Patel, Arthur Hale, Nicolas Osorio, Arfaj Mohammad, Ramaswamy Jothibasu et Elahbrouk Ehab. « Field Deployment of Nanomaterial Based Shale Inhibitors ». Dans Middle East Oil, Gas and Geosciences Show. SPE, 2023. http://dx.doi.org/10.2118/213743-ms.
Texte intégralRésumé :
Abstract Shale inhibition solutions that are commonly used in water-based fluids employ chemical systems that are not universally applicable. For example, kaolinite rich shales, can lose strength when exposed to KCl through cation exchange with potassium. In the United States, government regulations prohibit the disposal of greater than 3,000 ppm chloride on lease or 1,000 ppm chloride off lease. The hazardous nature of choline chloride restricts its use as shale inhibitor for water-based fluids. Nanosilica Based Shale Inhibitor (NSBSI) has been developed to mitigate the difficulties in clay stabilization in particularly challenging formations. NSBSI is used when drilling with low solids, non-dispersed muds, such as polymer and PAC muds. It can be used as an alternative to polyamine-based shale inhibitors and silicate-based shale inhibitors. Field trials were conducted in three wells. Commonly used shale inhibitor (polyamine based) were replaced by NSBSI in mud formulations in order to complete the field trials. Trouble-free drilling through problematic shale sections with no changes in mud properties, and no indications of lack of inhibition were experienced. Further addressing field requirements for shale inhibition in water-based muds, we have also developed a second shale-inhibiting product which is functionalized nanoplatelets composed of amine functionalities anchored on the nanometer-thick magnesium silicates (LMS-NH2). A facile synthetic approach was employed to synthesize lab-scale quantity of LMS-NH2 through combination of sol-gel and precipitation techniques. The structural characterization was conducted using powder X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) to evaluate generation of anticipated LMS-NH2. Shale stabilization characteristics of LMS-NH2 were tested and compared with other commercial shale inhibitors. Clay swelling and clay dispersion tests were performed to demonstrate the effectiveness of the impermeable coating of nano-platelets on to the clay-rich shales. The LMS-NH2 have demonstrated 87% recovery of swellable shales after dispersion tests. The microscopic study conducted on the treated shales reveals the formation of inorganic film on the shales, which provide impervious coating to protect the water susceptible clays. The linear swelling measurements were also performed to understand the effectiveness of LMS-NH2 over 72 hours demonstrating minimized the hydration and subsequent swelling of clay-rich shales. The newly developed inhibitor in the current study has outperformed conventional shale inhibitors wherein the presence of inorganic constituents aids stronger film formation compared to solely organic inhibitors. Comparative studies have been carried out against commercially used shale inhibitors using linear swell meter, dispersion test and pore pressure penetration test and the results will be presented.
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Ardant, Daria, Coralie Brumaud et Guillaume Habert. « Tackling Variability of Clay to Provide a Robust Binder ». Dans 4th International Conference on Bio-Based Building Materials. Switzerland : Trans Tech Publications Ltd, 2022. http://dx.doi.org/10.4028/www.scientific.net/cta.1.382.
Texte intégralRésumé :
Locally available and with infinite recycling possibilities, the use of earth as building material leads to one of the lowest environmental impacts in the construction sector. Recent advances in the earth materials field have been made based on concrete and ceramics technologies to facilitate its uses in dense areas. It is possible to modify clay particle interactions and the material's whole behavior by adding inorganic dispersants and flocculants into clay paste. Earth becomes easy to cast and unmold into formworks, and by removing cement in its composition, poured earth can reach a low CO2 emission rate. Even if this technology is promising, further work has to be performed, as it cannot be implemented on earth from excavation sites with high variability. Tackling the clay nature variability is now the main issue to push this product on the market with robust properties. This research investigates the robustness of the poured earth binder. In this way, several clays (three montmorillonites, two kaolinites, and binary mixes at different proportions) were investigated. Their compacity (C) was determined following the water demand protocol with Vicat apparatus and compared to their consistency properties (liquidity and plasticity limits), and a correlation between these values is established. Different clay pastes prepared at different solid volume fractions were tested to define the influence of the clay nature on the paste consistency evolution. The results showed that clay nature for paste at high solid volume fraction does not influence constituency's evolution when their respectivecompacity is taking into account. It can be suggested that for a clay binder with a consistency close to C, which might be mandatory for poured earth application, only the swelling capacity might influence the mix design.