O aumento do consumo de alimentos ricos em gorduras e carboidratos associado à reduzida prática de exercícios físicos pode ter como consequência o desenvolvimento da obesidade e de distúrbios metabólicos, tais como intolerância à glicose, resistência à insulina, diabetes tipo 2 e dislipidemias. O músculo esquelético contribui diretamente para o desenvolvimento e progressão dos distúrbios metabólicos, especialmente em decorrência da disfunção mitocondrial. Uma das ferramentas amplamente utilizada para o tratamento de distúrbios metabólicos é o treinamento físico, pois promove adaptações metabólicas no sentido oposto aos prejuízos metabólicos induzidos por dietas hipercalóricas. O presente estudo teve por objetivo avaliar se o treinamento físico aeróbio seria capaz de prevenir o desenvolvimento de distúrbios metabólicos induzidos por dieta hipercalórica composta por ração de cafeteria mais frutose e sacarose diluídas em água de beber em camundongos, e se essa resposta seria mediada por adaptações no músculo esquelético. Os resultados obtidos revelaram que o treinamento físico aeróbio preveniu os distúrbios metabólicos induzidos por dieta hipercalórica, tais como deposição de gordura, hiperfagia, hiperglicemia e aumento de pressão arterial, bem como melhorou a capacidade aeróbia. Essas respostas foram associadas apenas ao aumento na capilarização do músculo esquelético, já que a capacidade oxidativa determinada pela citrato sintase e a expressão da proteína PGC-1? não modificaram / The increased consumption of foods rich in fats and carbohydrates associated with reduced physical exercise may result in the development of obesity and metabolic disorders such as glucose intolerance, insulin resistance, type 2 diabetes and dyslipidemia. Skeletal muscle contributes directly to the development and progression of metabolic disorders, especially as a result of mitochondrial dysfunction. One of the tools widely used for the treatment of metabolic disorders is physical training, which promotes metabolic adaptations in the opposite direction to metabolic damage induced by hypercaloric diets. The present study aimed to evaluate whether physical training could prevent the development of metabolic disorders induced by hypercaloric diet consisting of cafeteria diet plus fructose and sucrose diluted in drinking water in mice, and if this response was mediated by adaptations in skeletal muscle. The results showed that physical training prevented metabolic disorders induced by hypercaloric diet, such as fat deposition, hyperphagia, hyperglycemia, increased blood pressure, and improved aerobic capacity. These responses were associated only with the increase in skeletal muscle capillarity, because oxidative capacity citrate synthase and protein expression of PGC-1? did not change

Orientador: Edison Bittencourt / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-23T04:07:07Z (GMT). No. of bitstreams: 1 Borelli_Camilla_D.pdf: 3705740 bytes, checksum: 0fb8d239f30de40d55f37f75f57bf221 (MD5) Previous issue date: 2013 / Resumo: O crescente interesse pelo conforto no vestuário, utilizado em atividades profissionais, práticas esportivas e até mesmo roupas casuais, impulsionou uma demanda pelo conhecimento das propriedades e funcionalidades que se almeja em relação à interação com o usuário. O transporte de umidade é um dos principais parâmetros relacionados ao conforto têxtil. A capacidade de um tecido transportar a transpiração da pele ao ambiente influencia diretamente na percepção de conforto. A medida de transporte de umidade configura-se como uma ferramenta valiosa na avaliação do desempenho e desenvolvimento de novos produtos têxteis, principalmente pela escassez de estudos envolvendo os tecidos planos produzidos com fios de poliéster. Com o objetivo de avaliar o conforto de artigos têxteis, através do transporte de umidade multidimensional, transporte de umidade por capilaridade, permeabilidade ao vapor e permeabilidade ao ar, foram comparados tecidos planos de poliéster produzidos com diferentes ligamentos e diferentes títulos de filamentos. Os resultados mostraram que a presença de filamentos mais finos (microfibras), aliada ao ligamento tela, favorece o transporte da umidade por capilaridade e a permeabilidade ao ar, enquanto que os parâmetros de transporte da umidade multidimensional e permeabilidade ao vapor não sofreram influência dos títulos dos filamentos e dos diferentes ligamentos, sendo unicamente influenciados pelas propriedades da matéria-prima / Abstract: The growing interest in clothing's comfort, used in professional activities, sports and even casual clothes, created a demand for knowledge of the properties and features desirable regarding interaction with the user. The moisture transport is one of the main parameters related to comfort. The ability to transport perspiration to environment, of a fabric, influences directly the perception of comfort. The measurement of the moisture transport is a valuable tool in assessing the performance and development of new textile products, mainly because there are not many studies on polyester woven fabrics. In order to evaluate the behavior of textile's comfort, by moisture multidimensional transport, moisture transport by capillarity (wicking), vapor permeability and air permeability, polyester woven fabrics produced with different weaves and filament's yarn count number were compared. The results showed that the presence of finer filaments (microfiber), coupled with twill weave, facilitates capillarity moisture transport and air permeability, while the multidimensional moisture transport and vapor permeability parameters are not influenced by different filament's yarn count number and weaves, only influenced by the properties of the raw material / Doutorado / Ciencia e Tecnologia de Materiais / Doutora em Engenharia Quimica

Le développement récent de la nanofluidique pose de nombreuses questions concernant les lois et longueurs caractéristiques qui régissent l’hydrodynamique et le mouillage à l’échelle du nanomètre. Pour aborder ce sujet, nous avons utilisé des techniques de microscopies avancées en sondant l’interface liquide/air à l’aide de pointes non conventionnelles. L’AFM utilisé dans le mode oscillant modulation de fréquence (FM-AFM) donne accès, de manière indépendante, à la force exercée par le liquide pendant une approche-retrait, et aux composantes conservatives et dissipatives de l’interaction pointe-ménisque. Des expériences complémentaires menées en microscopie électronique (MEB) permettent de visualiser le nanoménisque créé et de mesurer la force capillaire résultante. La couche visqueuse entraînée par l’oscillation de la pointe est d’abord étudiée. Le coefficient de friction et la masse ajoutée sont mesurés par FM-AFM en fonction de la viscosité des liquides et de la fréquence d’excitation. Un modèle basé sur une description classique rend compte quantitativement de l’ensemble des résultats expérimentaux permettant ainsi une évaluation du champ de vitesse entraîné par la nanosonde.Les méthodes développées ont permis d’étudier les caractéristiques de l’interface liquide. Le profil du nanoménisque est modélisé et validé grâce aux observations MEB. La raideur du ménisque mesurée expérimentalement par FM-AFM et décrite théoriquement démontre une dépendance logarithmique avec l’extension latérale du ménisque.Des résultats préliminaires sont également obtenus avec des pointes de carbone sur lesquelles glisse la ligne de contact, donnant accès à la dissipation dans le nanoménisque et à la ligne de contact, ainsi qu’à l’ancrage sur des défauts uniques, un des problèmes ouverts de la physique du mouillage.Cette étude démontre que le FM-AFM et le MEB sont des outils pertinents pour sonder quantitativement les propriétés des liquides à l’échelle nanométrique, ouvrant la voie à des études systématiques sur le mouillage à l’échelle nanométrique / The recent development of nanofluidic raises many issues about laws and characteristic lengths governing hydrodynamics and wetting at the nanometer scale. To address this issue, we used advanced microscopy techniques to probe the liquid/air interface with unconventional tips. The oscillating frequency modulation mode (FM-AFM) of the Atomic Force Microscope (AFM) gives independent access to the force applied by the liquid during an approach-withdrawal ramp, and to the conservative and dissipative components of the tip-meniscus interaction. Additional experiments conducted by electron microscopy (SEM) helped visualizing the shape of nanomeniscus to measure the resulting capillary force.The viscous layer set in motion by the oscillation of the tip is studied first. The friction coefficient and the added mass are measured by AFM-FM as a function of the viscosity of the liquid and of the excitation frequency. A model based on a classical description reflects quantitatively all experimental results enabling an evaluation of the velocity field caused by the nanoprobe.The developed methods also served to study the properties of the liquid interface. Nanomeniscus profile is modeled and validated through SEM observations. The stiffness measured experimentally by FM-AFM and described theoretically shows a logarithmic dependence with the lateral extension of the meniscus.Preliminary results are also obtained with carbon tips on which the contact line slides, giving access to the energy dissipation in the nanomeniscus and at the contact line, as well as to the anchoring of single defaults, an open issue of wetting physics.This study demonstrates that FM-AFM and SEM are relevant tools to probe quantitatively the properties of liquids at the nanoscale, opening the way for systematic studies on wetting at the nanoscale

<b>Structure of the thesis</b><p><p>The present work has been organized in two main parts: in the first one, the focus will be on the scientific and theoretical aspects of the evaporation process in presence of an inert gas flow while in the second all the technical aspects and more practical tests related to the real implementation of the micro-gravity experiment CIMEX-1 will be detailed. In any cases, the discussion will always start from the phenomenology observed considering that ” Nature is far more reach of any speculations.”<p><p><b>Part I: Evaporation in presence of inert gas</b> <p><p>In chapter 1, a detailed presentation of the experimental setups for the on-ground tests is given together with the presentation of the qualitative and quantitative results obtained. Actually, the main parameters that regulate such kind of experiments are the mass flow rate of inert gas, the total pressure of the cell and the geometrical shape and dimensions of the evaporating regions.<p>Consequently, the experiments aimed at covering the maximal possible combination of these three parameters with special attention to the variation of the inert gas flow and of the thickness of the evaporating liquid layer. More precisely, the liquid layer thickness was in the range 1.2 to 3.8 mm while the inert gas flow was set in the range 50 to 2500 ml/min. The pressure has been partially neglected as control parameter because its control was discovered not to be very reliable.<p>The visualization system used in all the experiments consisted in a opportunely calibrated infrared camera. It allowed for having a quantitative analysis of the temperature distribution at the interface of the evaporating liquid.<p>The infrared images also helped to follow the thermal history of the interface. In many cases, it has been possible to clearly observe the evolution of instability patterns at the interface that represent an original contribution to the understanding of such a kind of phenomena.<p>The physical and mathematical modeling of the observed phenomenology will be the subject of the chapter 2. One of the peculiar issue of the problem under consideration is that the thermal gradient normal to the interface is not directly imposed like in the usual Marangoni-Bénard experience, but is a result of the cooling of the interface due to the evaporation.<p>Moreover,the interface is subject to the shear stress of the inert gas flow and to the one due to the thermo-capillarity. Finally, the gas phase is to be considered as a mixture; this oblige to solve a diffusion problem in the gas phase. A physical model that takes into account the different aspects mentioned above is presented together with the governing equations and the appropriate boundary conditions.<p>Numerical issues involved in solving the model are also analyzed. Numerical results obtained are finally discussed and compared when possible with experimental results.<p><p><b>Part II: Preparation of the CIMEX-1 experiment on-board the International Space Station.</b><p><p>In chapter 3, we will describe the main platforms used to perform low-gravity experiments. They will be classified according to the low-gravity level and to the low-gravity interval duration that could be ensured for experiments. According to these criteria, the list of the low-gravity platforms will be as follows: Drop Towers with ≈ 4 sec. of micro-gravity, Parabolic Flights that can assure not more than ≈ 25 sec. Sounding Rockets with a low-gravity time of the order of several minutes depending on the rockets, Foton Capsules that assure for many days of high quality - i.e. without perturbations - low-gravity level and ,last but not least, the International Space Station where the low-gravity duration could be even of several weeks which is a sufficient time duration for the most part of the experiments.<p>The chapter 4 will be entirely devoted to the ITEL experiment that is the precursor and the core of the CIMEX-1. After a brief overview of the experiment that has been performed twice on-board sounding rockets of the MASER class, the experimental setups used both on-ground and in micro-gravity will be detailed.<p>The focus will be on the experimental results obtained on-ground during the preparatory tests and during the two sounding rocket flights with special attention to the first one. The analysis will be supported by the presentation of many results obtained in numerical simulations.<p>The two parabolic flight campaigns performed to test one of the key sub-systems of the CIMEX-1 setup are the subject of the chapter 5. The separating-condensing unit is mandatory for performing the experiment on-board the International Space Station because the limitations on the crew intervention oblige to have a closed loop experiment.<p>The goal of the two parabolic flights will be detailed together with the setup and the experimental scenario. The main results will be also shown and some considerations on the efficiency of the system will be presented.<p>It is worthy to stress that the results obtained during these parabolic flights have been determinant at the European Space Agency level to fly the CIMEX-1 experiment on-board the International Space Station.<p>Finally, in the section conclusions and perspectives the main results obtained will be summarized together with the new scenarios opened by the present work and some guidelines for further development in the experimental, theoretical and technical analysis. / Doctorat en sciences appliquées / info:eu-repo/semantics/nonPublished

Nous étudions le comportement rhéologique de suspensions de bulles dans un fluide à seuil. Des suspensions modèles sont formulées par l'incorporation de bulles d'air monodisperses dans un fluide à seuil modèle, qui se comporte comme un solide visco-élastique pour de faibles déformations et s'écoule en suivant une loi de Herschel-Bulkley si la contrainte appliquée est supérieure à sa contrainte seuil. Nous caractérisons le module complexe, la contrainte seuil et la loi de comportement en écoulement de ces fluides à seuil aérés modèles. Pour des fractions volumiques en gaz inférieures à la fraction critique de percolation des bulles dans le fluide à seuil, la réponse macroscopique des suspensions de bulles est le résultat d'un couplage entre la rhéologie du fluide à seuil interstitiel et la capillarité qui s'exerce à la surface des bulles. Les grandeurs rhéologiques mesurées sur les suspensions décroissent d'autant plus avec la fraction volumique en gaz que les effets capillaires sont faibles. L'introduction de plusieurs nombres capillaires permet de quantifier ce couplage et de comparer les résultats expérimentaux obtenus à une estimation micro-mécanique. Au-delà de la fraction volumique critique de percolation des bulles, le matériau aéré devient une mousse de fluide à seuil dans laquelle le fluide à seuil interstitiel est confiné dans les bords de Plateau. Ce confinement entraîne l'apparition d'effets de taille finie lorsque la mousse de fluide à seuil est cisaillée, et la réponse macroscopique de la mousse dépend de la microstructure du fluide à seuil interstitiel / The rheological behaviour of suspensions of bubbles in yield stress fluids is investigated through experiments on model systems. Model foamed yield stress fluids are prepared by adding monodisperse bubbles in model yield stress fluids, which behave as soft visco-elastic solids for small deformation and flow with a Herschel-Bulkley law above their yield stress. The complex modulus, yield stress and flow curve of those model foamed yield stress fluids is characterised by rheometrical measurements. For gas volume fractions lower than the percolation threshold of the bubbles in the suspending yield stress fluid, the macroscopic behaviour of the bubble suspensions results from the coupling of the fluid rheology to capillarity acting on the surface of the bubbles. The rheological properties of the suspensions decrease all the more with the gas volume fraction as capillarity is weak. This coupling is quantified through capillary numbers which also allow us to compare our experimental results to micro-mechanical estimates. For higher gas volume fractions, beyond the percolation threshold of the bubbles, the aerated material turns into an actual foam of yield stress fluid in which the interstitial fluid is confined in the Plateau borders. This confinement leads to the onset of finite-size effects as the foam is sheared, and the macroscopic behaviour of the foam depends on the micro-structure of the interstitial yield stress fluid

Beams are ubiquitous in our everyday life and can be found in a variety of length scales, from large supports of buildings to carbon nanotubes. Similarly, bubbles can also span a variety of scales, ranging from tiny bubbles in a glass filled with champagne to the giant soap bubbles formed by artists to attract crowds. Yet, the behavior of beams and bubbles can often occur so fast that the dynamics go unnoticed. This dissertation aims to understand the mechanics of beams and bubbles in four different examples. We combine table-top experiments with mathematical models to predict how each system will behave when exposed to different extreme conditions. We start by examining the retraction of a rubber band once it has been stretched and released. This process is similar to plucking a string, where the dynamics are governed by tensile and inertial forces, resulting in a trapezoidal shape during retraction. However when a rubber band is stretched and released, a region of high-curvature develops. Our experiments and mathematical model highlight that bending forces can be significant and give rise to a curved self-similar shape to the retracting rubber band. The next example involves the competition of surface tension and twisting on a flexible rod. Most studies in the field of elasto-capillarity have focused on how surface tension can bend an elastic structure, leaving the possibility of twisting unexplored. Here we utilize particles with discrete wettabilities -- or Janus particles -- at liquid interfaces that can be used to twist a flexible cylinder. The third system is focused around the spreading behavior of bubbles on submerged surfaces coated with a layer of oil. These liquid-infused surfaces have remarkable applications due to their ability to minimize contact line pinning. However, this property has mostly been exploited using liquid drops. We here study the early spreading behavior of a bubble once it has made contact with the liquid-infused surface. The final chapter is centered around the collapse of bubbles resting on the surface of an ultra viscous liquid. When a bubble on such a surface is ruptured, the bubble film collapses vertically downwards, leading scientists to believe that gravity is driving the collapse. Yet, interfacial forces are dominant in highly curved liquid surfaces and exceed gravitational forces. By turning the setup upside-down, we show that surface tension is indeed responsible for the collapse and the subsequent wrinkling instability that develops.

Although the global energy demand is shifting towards a well-balanced energy mix, fossil fuels will continue to have a significant role in this transition and will maintain a big share in the energy mix portfolio. The production of oil and gas has already reached the apex in the time that most of the conventional giant reservoirs are depleting, and discoveries for new reserves have shrunk down. In conventional reservoirs, it is estimated that about two-thirds of the Original Oil in Place (OOIP) will not be produced within the field lifecycle, corresponding to an average Recovery Factor (RF) between 20% and 40%. This low recovery factors from traditional methods trigger more investments in the Enhanced Oil Recovery (EOR) techniques. Waterflooding is one of the most commonly used technique to increase RF by raising or maintaining reservoir pressure. Lack of comprehending the driving forces in Naturally Fractured Reservoirs and reservoir heterogeneity may lead to serious conformance problems in which dealing with excessive undesirable water production becomes very challenging. Chemical EOR through an injection of a polymer solution is amongst the tested options that can be used to improve sweep efficiency. Ultimately, understanding the reservoir characteristics and having the know-how to implement the best recovery option will help to maximize the field’s lifecycle and increase the RF. Therefore, this study investigates some key elements that have a significant influence on the overall fluid flow behavior. The work reveals insights on the impact of capillarity and wettability in heterogeneous porous media. An experimental lab-scale consisting of a 2D sandbox model, which mimics a water-wet fractured system with injection and production ports, was designed, fabricated, and tested in single-phase and two-phase flow scenarios including the injection of water and polymer solutions. In the case of single-phase flow, a waterflood baseline scenario was studied with controlled variables, which helped to distinguish the contrast with the polymer flood case. Implementing water injection in a fractured water-wet reservoir showed that water prefers to channel through high permeable streaks, which consequently leads to poor volumetric sweep leading to significant bypassed zones. Investigating the two-phase flow was the essence of this research. Thus, the same procedures were repeated where water and polymer were used to displace oil. During waterflooding, due to strong capillarity contrast between the matrix and fracture media, flow divergence was found to be faster towards the matrix medium where the matrix gets saturated faster than that the fracture, overriding the high permeability of the fracture. Whereas, polymer flooding exhibited better volumetric sweep in all scenarios. Numerical simulations were used to replicate the experiments. This work can give new visual insights about key recovery mechanisms in heterogeneous reservoirs using polymers.

Capillary flows continue to be important in numerous spacecraft systems where the effective magnitude of the gravity vector is approximately one millionth that of normal Earth gravity. Due to the free fall state of orbiting spacecraft, the effects of capillarity on the fluid systems onboard can dominate the fluid behavior over large length scales. In this research three investigations are pursued where the unique interplay between surface tension forces, wetting characteristics, and system geometry control the fluid behavior, whether in large systems aboard spacecraft, or micro-scale systems on Earth. First, efforts in support of two International Space Station (ISS) experiments are reported. A description of the development of a new NASA ground station at Portland State University is provided along with descriptions of astronaut training activities for the proper operation of four handheld experiments currently in orbit as part of the second iteration of the Capillary Flow Experiments (CFE-2). Concerning the latter, seven more vessels are expected to be launched to the ISS shortly. Analysis of the data alongside numerical simulations shows excellent agreement with theory, and a new intuitive method of viewing critical wetting angles and fluid bulk shift phenomena is offered. Secondly, during the CFE-2 space experiments, unplanned peripheral observations revealed that, on occasion, rapidly compressed air bubbles migrate along paths with vector components common to the residual acceleration onboard the ISS. Unexpectedly however, the migration velocities could be shown to be up to three orders of magnitude greater than the appropriate Stokes flow limit! Likely mechanisms are explored analytically and experimentally while citing prior theoretical works that may have anticipated such phenomena. Once properly understood, compressed bubble migration may be used as an elegant method for phase separation in spacecraft systems or microgravity-based materials manufacturing. Lastly, the stability of drops on surfaces is important in a variety of natural and industrial processes. So called 'wall-edge-vertex bound drops' (a.k.a. drops on blade tips or drops on leaf tips which they resemble) are explored using a numerical approach which applies the Surface Evolver algorithm through implementation of a new file layer and a multi-parameter sweep function. As part of a recently open sourced SE-FIT software, thousands of critical drop configurations are efficiently computed as functions of contact angle, blade edge vertex half-angle, and g-orientation. With the support of other graduate students, simple experiments are performed to benchmark the computations which are then correlated for ease of application. It is shown that sessile, pendant, and wall-edge bound drops are only limiting cases of the more generalized blade-bound drops, and that a ubiquitous 'dry leaf tip' is observed for a range of the critical geometric and wetting parameters.

Let A be an Euclidean open Lipschitz set. This dissertation aims to discuss some results concerning the boundary regularity for almost-minimizers of the relative perimeter in A. An almost-minimizer of the relative perimeter in A is a measurable set E that minimizes the perimeter functional P(E;A), roughly speaking the (n-1)-area of the boundary of E in A, among local competitors for E. Important examples of almost-minimizers in A are given, for instance, by the solutions to relative isoperimetric problems like min { P(E;A) : E is contained in A and |E| = m}. While when A is smooth the theory of the boundary regularity for almost-minimizers is well-established, little is known when the boundary of A contains singular points such as edges, vertices, cusps, etc. In particular, we prove a boundary Monotonicity Formula, holding under a so-called visibility condition on A at a point x on the boundary of A, and a Vertex-skipping Theorem, valid when n = 3 and A is convex. This latter result establishes that the closure of the boundary of an almost-minimizer of the relative perimeter in a 3-dimensional open, convex set A cannot contain vertex-type singularities of the boundary of A. The optimality of the dimensional restriction n = 3 is also examined in the thesis.

La récupération assistée du pétrole implique la progression dans unmilieu poreux d'une phase aqueuse qui pousse une phase organique. Al'échelle du pore, les forces visqueuses et la gravité sontnégligeables, et la capillarité joue un rôle prépondérant : ledéplacement des fluides est gouverné par leur affinité avec lessurfaces et par les hétérogénéités de canaux. Les films liquidesexistent dans les pores d'une roche. Trois systèmes microfluidiquessont mis en place pour étudier le rôle des films microscopiques (demouillage) ou des films macroscopiques (de coins). Le premier consisteen un capillaire de section circulaire dans lequel on suit lemouvement d'un ménisque dans des conditions de mouillage variées. Enparticulier, en mouillage pseudo-partiel, un hystérésis d'angle decontact est observé, mais les films de mouillage présents dans cesystème conduisent à un accrochage de ligne de contact beaucoup plusfaible qu'en absence de film. Les deuxième et troisième systèmesmettent en évidence l’influence des films de coins dans un canalrectangulaire sur l'avancée du ménisque. Le couplage de l'écoulemententre la phase du coin et la phase du milieu entraîne le drainage del’huile piégée. Les propriétés de ce nouveau mécanisme sontcaractérisées par des expériences et s’accordent avec le modèleconstruit. / Enhanced oil recovery involves the displacement of an organic fluid byan aqueous one in the pores of the rocks. At the pores scale. Thedisplacement of fluids is governed by wetting condition of the system.The viscous and gravity forces are negligible and the capillarityplays a dominant role heterogeneities of channel sizes. Threemicrofluidic systems are designed to study experimentally the role ofmicroscopic liquid films (wetting) or macroscopic ones (corners) inthe pores level. The first one consists of the displacement of ameniscus in a circular capillary with various wetting conditions. Inparticular, for pseudo-partial wetting systems, a contact anglehysteresis is observed but with a weak pinning as compared to partialwetting systems where there are non wetting films. The second andthird ones show the influences of liquid films in the corners of asquare channel. The coupling between the corner flows and the mainflow involves the drainage of the trapped oil cluster. The propertiesof this new mechanism are consistent with the theoretical model, andalso characterized by experiments.