A curva de retenção da água no solo é um dos principais instrumentos para avaliar a qualidade física dos solos e possibilitar seu manejo adequado. Por meio da Teoria da Capilaridade vários equipamentos foram desenvolvidos para determinar a intensidade com que a água está retida ao solo, porém, pouco se tem dado atenção para verificar se os pressupostos para o real funcionamento da teoria estão sendo atendidos. Um aspecto refere-se ao tamanho da amostra utilizada para determinar a curva de retenção, de modo que haja continuidade dos feixes capilares na amostra e placa porosa. Desta forma, este trabalho propõe avaliar diferentes tamanhos de amostra indeformada para a determinação da curva de retenção. Para isso, coletaram-se amostras em anéis volumétricos cilíndricos de três tamanhos (altura) diferentes (T1 - 0,075 m; T2 - 0,05 m; T3 - 0,025 m;) e mesmo diâmetro interno (0,07 m), dos horizontes diagnósticos de um Latossolo e um Nitossolo em áreas experimentais da Escola Superior de Agricultura Luiz de Queiroz (Esalq/USP), Piracicaba - SP. Realizou-se a caracterização física destes solos, por meio da análise granulométrica, densidade do solo, densidade de partículas, porosidade total e teor de carbono orgânico. As curvas foram determinadas para cada tamanho de amostra, utilizando-se o Funil de Haines, para as tensões 0,5, 1, 4, 6 e 10 kPa, e a Câmara de Pressão de Richards para 33, 100 e 500 kPa. As curvas de retenção foram ajustadas pelo modelo utilizado por van Genuchten. Estimadas as curvas, avaliou-se a distribuição de poros do solo das amostras, determinando-se a curva de frequência acumulada de poros em função do logaritmo do raio e, depois pela diferenciação das equações de ajuste das curvas de retenção, a curva diferencial de frequência acumulada de poros. Os resultados mostram que o Latossolo, por ter textura arenosa no horizonte estudado, não apresentou diferença significativa nas curvas de retenção para os tamanhos das amostras estudadas. Verificou-se pouca modificação na distribuição dos poros deste solo, que possui teor elevado das frações areia fina e muito fina, e desenvolveram papel importante para a retenção de água. O Nitossolo, por sua vez, apresentou diferença significativa da curva obtida pela amostra de menor tamanho (T3), havendo maior retenção de água com a diminuição do tamanho da amostra. Devido a sua textura muito argilosa, o arranjo estrutural deste solo foi diferenciado ao se utilizar as amostras maiores, com provável interrupção e descontinuidade dos feixes capilares. Consequentemente, houve também alteração na distribuição dos poros, com redução dos mesoporos e aumento dos microporos. Desta forma, pode-se concluir que o tamanho da amostra influenciou a curva de retenção da água devido à complexidade estrutural do solo, que provavelmente é diferente nas amostras maiores por causa da continuidade dos feixes capilares, principalmente no Nitossolo. Em outras palavras, quanto menor o tamanho da amostra há menor diferenciação no arranjo de poros, ou seja, maior proximidade da real condição do solo e, assim, uma interpretação da retenção de água \"mais correta\" por meio da Teoria da Capilaridade. / The soil water retention curve is one of main tools to assess the physical quality of the soil and to make possible its adequate management. By means of the Capillary Theory, many instruments have been developed to determine the water retention forces in soil, but, little attention has been given to check whether the assumptions for the application of the theory are being attended. One aspect relates to the sample size used to determine the retention curve, so that there is capillary continuity of the sample and porous plate. Thus, this study aimed to evaluate different sizes of undisturbed cylindrical samples for determination of the retention curve. The samples were collected from diagnostic horizons of Latosol and a Nitosol, in experimental areas of the Escola Superior de Agricultura Luiz de Queiroz (Esalq/USP), Piracicaba - SP. Three volumetric rings with three different heights (T1 - 0,075 m; T2 - 0,05 m; T3 - 0,025 m;), were used the diameter of the rings were the same for the three sizes (0,07 m). The physical characterization soils were made by the granulometric analysis, bulk density, particle density, porosity and organic carbon. The curves were determined for each sample size, using the Haine\'s funnel, for tensions 0.5, 1, 4, 6 and 10 kPa, and Richard\'s pressure chamber for 33, 100 and 500 kPa. The pore size distribution of the soil was evoluated first by determining the cumulative frequency curve of pore radius, and then, by differentiating fitling equation of fluis curve to obtain a differential curve of pore cumulative frequency. The retention curves were fitted by the model used by Van Genuchtem. The results showed that in the Latosol there was no significant difference in retention curves for the sizes of the samples studied. There was little change in pore distribution of the fluis soil with high content of fractions fine and very fine sand, that developes significant role in soil water retention. The Nitosol exhibited significant difference of the curve obtained by the smallest size sample (T3), with greater water retention with the decreasing of the sample size. Because of its very clayey texture, the structural arrangement of this soil was different when larger samples were used, with probable interruption and discontinuity of capillaries. Consequently there was also a change in the pore distribution, with reduction of mesopores and an increase of micropores. Thus, itean be conclude that the sample size influenced the soil water retention curve due to the structural complexity of the soil that probably is different in the bigger sample because of the continuity of the capillary budles fluit was more affected in the Nitosol. In other words, the smaller the sample size, the smaller the difference in the arrangement of pores, that is, more closeness of the actual condition of the soil and so a \"more correct\" interpretation of soil water retention by capillary theory.

The present study deals with the physical characterization of macrodefect free cements produced by ICI. These materials are made through a specialized mixing technique which incorporates an organic polymer into the cement/water system. The high mechanical strength and low porosity of this class of hardened cement paste had been well documented, however, a detailed characterization of the physical nature of the microstructure had not previously been attempted. Two classes of macrodefect free material were studied, based on Ordinary Portland cement and High Alumina cement, respectively. The porosities of these two materials were determined in their original state and after various forms of heat treatment and conditioning. Samples based on Ordinary Portland cement had a well defined narrow pore size distribution, even after heat treatment, while the High Alumina cement samples displayed a very low total pore volume in their original state, but subsequent heat treatment led to the developement of porosity over a wide range of pore sizes. These fundamental differences in the pore size distributions had significant effects on the homogeneity and reproducibility of the microstructures of the samples. The porosity generated by heat treatment was found to be unstable in the presence of water. In general, reductions in the porosities and permeabilities were observed. This was due to the formation of fresh cement hydrate gel within the pore structure, which caused a shift in the pore size distributions towards smaller pores.

Des gammes de membranes en poly(étherimide) (PEI) fonctionnalisées avec des tailles de pores contrôlées ont été préparées en se basant sur deux étapes successives : élaboration des membranes UF de seuil de coupure (MWCO) de 120 ± 10 kDa par la technique inversion de phase induite par la coagulation dans l'eau suivie d'un traitement de surface par une solution aqueuse contenant des oligomères aminés. Une modification avec un dérivé monoaminé commercial, le Jeffamine M-2070, a donné des membrane recouvertes de brosses de courtes chaines de poly(éthylèneglycol) (PEG-PEI) qui ont rendu la membrane plus hydrophile et plus résistante au colmatage par le BSA avec un taux de récupération de flux de l'ordre de 80 à 93 % (traitement de 1 à 3 h). Le MWCO des membranes PEG-PEI traitées plus que 3 h augmente progressivement pour atteindre 500 kDa après 5 h de traitement. D'autre part, une réaction avec des oligomères de poly(éthylèneimine) a donné des membranes chargées positivement (Cat-PEI) en rétrécissant la taille des pores pour atteindre des gammes de membranes d'UF serrée et de NF. Des membranes Cat-PEI de NF de MWCO de l'ordre de 300-500 Da sont adaptées au dessalement avec par un ordre de rétention décroissant de sels simples de CaCl2 > NaCl > MgSO4 > Na2SO4. La forte rétention des ions Ca2+ (plus que 90 %) rend ces membranes très efficaces pour l'adoucissement d'eau (diminution de la dureté d'une eau du robinet de 37 à 7°F). Les membranes Cat-PEI ont montré aussi, une bonne rétention des acides aminés basiques (plus que 80 % pour l'Arginine et la Lysine) à un pH entre 3 et 6. Ainsi une sélectivité expérimentale de l'ordre de 20 a été obtenue pour des mélanges d'acide glutamique et d'arginine avec des membranes de MWCO entre 500 et 750 Da. / Functionalized poly(etherimide) (PEI) membranes with controlled pore size were prepared based on two steps : preparation of UF membranes with a molecular weight cut-Off (MWCO) of 120 ± 10 kDa by phase inversion induced by coagulation in water followed by a surface treatment with an aqueous solution containing amino oligomers. Modification with a commercial monoamine derivative, Jeffamine M-2070, gave membranes (PEG-PEI) coated with brushes of poly (ethylene glycol) short chains that made the membrane more hydrophilic and more resistant to fouling by BSA with a recovery flow rate of of 80 to 93 % (treatment of 1 to 3 h). The MWCO of PEG-PEI membranes treated more than 3 h became progressively larger and reached 500 kDa after 5 h of treatment. On the other hand, reaction with oligomers of poly (ethyleneimine) gave positively charged membranes (Cat-PEI) by narrowing the pore size yielding tight UF and NF membranes. Cat-PEI NF membranes with MWCO of about 300-500 Da are suitable for desalination with a retention order of decreasing simple salts CaCl2> NaCl> MgSO4> Na2SO4. The high retention of Ca2+ ions (more than 90%) make Cat-PEI effective membranes for softening water (reducing the hardness of tap water from 37 to 7 °F). In addition, Cat-PEI membranes showed a good retention of basic amino acids (more than 80% for arginine and lysine) at pH between 3 and 6. Thus, an experimental selectivity of about 20 was obtained for a glutamic acid and arginine mixture using Cat-PEI membranes with a MWCO between 500 and 750 Da.

An adsorbent suitable for adsorption desalination cycles is essentially characterized by a hydrophilic and porous structure with high surface area where water molecules are adsorbed via hydrogen bonding mechanism. Silica gel type A++ possesses the highest surface area and exhibits the highest equilibrium uptake from all the silica gels available in the market, therefore being suitable for water desalination cycles; where adsorbent’s adsorption characteristics and water vapor uptake capacity are key parameters in the compactness of the system; translated as feasibility of water desalination through adsorption technologies. The adsorption characteristics of water vapor onto silica gel type A++ over a temperature range of 30 oC to 60 oC are investigated in this research. This is done using water vapor adsorption analyzer utilizing a constant volume and variable pressure method, namely the Hydrosorb-1000 instrument by Quantachrome. The experimental uptake data is studied using numerous isotherm models, i. e. the Langmuir, Tóth, generalized Dubinin-Astakhov (D-A), Dubinin-Astakhov based on pore size distribution (PSD) and Dubinin-Serpinski (D-Se) isotherm for the whole pressure range, and for a pressure range below 10 kPa, proper for desalination cycles; isotherms type V of the International Union of Pure and Applied Chemistry (IUPAC) classification were exhibited. It is observed that the D-A based on PSD and the D-Se isotherm models describe the best fitting of the experimental uptake data for desalination cycles within a regression error of 2% and 6% respectively. All isotherm models, except the D-A based on PSD, have failed to describe the obtained experimental uptake data; an empirical isotherm model is proposed by observing the behavior of Tóth and D-A isotherm models. The new empirical model describes the water adsorption onto silica gel type A++ within a regression error of 3%. This will aid to describe the advantages of silica gel type A++ for the design of adsorption desalination processes where reducing capital cost and footprint area are highly important parameters to take into account.

Three-dimensional fibrillar networks reconstituted from collagen I are widely used as biomimetic scaffolds for in vitro and in vivo cell studies. Various physicochemical parameters of buffer conditions for in vitro fibril formation are well known, including pH-value, ion concentrations and temperature. However, there is a lack of a detailed understanding of reconstituting well-defined 3D network topologies, which is required to mimic specific properties of the native extracellular matrix. We screened a wide range of relevant physicochemical buffer conditions and characterized the topology of the reconstituted 3D networks in terms of mean pore size and fibril diameter. A congruent analysis of fibril formation kinetics by turbidimetry revealed the adjustment of the lateral growth phase of fibrils by buffer conditions to be key in the determination of pore size and fibril diameter of the networks. Although the kinetics of nucleation and linear growth phase were affected by buffer conditions as well, network topology was independent of those two growth phases. Overall, the results of our study provide necessary insights into how to engineer 3D collagen matrices with an independent control over topology parameters, in order to mimic in vivo tissues in in vitro experiments and tissue engineering applications.

A systematic NMR cryo-porometry and -diffusometry study using nitrobenzene as a probe liquid is carried out in order to characterise pore structures of hierarchically-organised porous silica monolith possessing mesopores along with a 3D bicontinuous macropore network. The result obtained from NMR cryoporometry shows the presence of a relatively wide mesopore size distribution of 10-35 nm. Furthermore, NMR cryodiffusometry indicates that whilst the mesopores are highly tortuous (Tmeso ≈6), they have little influence on the overall tortuosity of the material (Tmacro ≈1.5), which is largely dominated by the macropores (Toverall ≈1.7).

Subscription articles: Theses and dissertations which contain embedded PJAs as part of the formal submission can be posted publicly by the awarding institution with DOI links back to the formal publications on ScienceDirect.doi:10.1016/j.msec.2015.10.069 / 京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第19578号 / 医博第4085号 / 新制||医||1013(附属図書館) / 32614 / 京都大学大学院医学研究科医学専攻 / (主査)教授 安達 泰治, 教授 開 祐司, 教授 妻木 範行 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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