Qanat system, an ancient water management system in Iran: History, architectural design and fish diversity

Ancient Iran is one of the leading civilizations that actively appear to water resources management, especially by the invention of "Qanat", an artificial underground system/ subterranean tunnel-wells system where the water flows through gravity on a slight slope in arid and semi-arid regions at least 5000 years ago. Qanats were innovated in ancient Iran, spread throughout much of the Middle East, and extended into North Africa, Spain, Italy, and South Asia. Tools preparation, size selection, digging the first and deepest vertical shaft known as "mother-well", digging several other vertical shafts along a line between the mother-well and Qanat outlet, and constructing a horizontal connection between vertical shafts (known as the main tunnel), which guides the water out through an outlet, are the main steps in Qanat construction. By this innovation, Iranian solved their water-related problems using the basic concepts of Hydraulics. In the same way, water-related infrastructures were built using locally available materials to make a better life for humans and other wonderful well-designed and well-adapted organisms in dry and semi-dry regions, yielding great civilization with a simple, but a fantastic architecture that provides cold water in hot summer and warm water in cold winter. By means of these ancient underground structures, water was funneled from mountainous areas and aquifers to lower lands and thus alluvial fans could be opened up to settlement, and an agrarian civilization developed and evolved. In addition, Qanat provides a continual flow suitable for many aquatic organisms, including crabs, amphipods (gamarids), freshwater shrimps, and fishes. Qantas are home and refugia to about 42 fish species (36 native and 6 exotic species) belonging to 20 genera, 7 families, and 2 orders. The Qanat ichthyofauna is dominated by Cyprinidae with 19 species (45.2 %) followed by Leuciscidae and Nemacheilidae (6 species, 14.28% each), Poeciliidae and Aphaniidae (4 species, 9.52%), and Cobitidae (1 species 2.38%). It is about 14% of the total ichthyofauna of Iran. The Qanat ichthyofauna comprises 36 natives (including 20 endemics) and 6 exotic species. Qanat fauna dominates by species that are generally of small size, are broadcast spawners, nonmigratory, and have a wide tolerance of environmental conditions

Hydrodynamics of Bubble Column Reactors Operating with Non-Newtonian Liquids

Dans l'industrie, de nombreux procédés nécessitent le contact entre une phase gazeuse et une phase liquide, avec ou sans solide en suspension, et ce afin de donner lieu à une grande variété de réactions chimiques. Bien que de nombreux types de réacteurs peuvent être utilisés à cet effet, au cours de la dernière décennie les réacteurs à colonne à bulles ont reçu une attention particulière car ils offrent certains avantages uniques tels que la facilité d'utilisation, des taux élevés de transfert de masse et de chaleur, et des frais d'entretien réduits en raison de l'absence de pièces mécaniques en mouvement. La conception et la mise à l'échelle d'une colonne à bulles nécessitent une compréhension complète de son hydrodynamique complexe. Ce dernier dépend des propriétés physiques des phases liquides et gazeuses, des conditions d'opération, et des paramètres de conception. A l'heure actuelle, du au manque de connaissance de ces systèmes, la conception des colonnes à bulles nécessite généralement des études expérimentales à différentes échelles (laboratoire, pilote, etc.), ce qui est coûteux en capital et en temps. Au cours des dernières années, les liquides et les solutions aqueuses en suspension utilisées dans les colonnes à bulles sont visqueuses et présentent habituellement, aux conditions opératoires utilisées, des comportements non newtoniens complexes. De plus, dans les colonnes à bulles utilisant des liquides non-newtoniens, non seulement la viscosité du liquide est habituellement variable selon les conditions d'écoulement, mais également leurs éventuelles propriétés élastiques. Pour cette variété de liquides non-newtoniens possédant des propriétés élastiques, ces dernières sont susceptibles d’affecter et de modifier fortement les comportements des bulles. En dépit de la demande croissante d'utilisation de fluides non newtoniens dans les réacteurs à colonnes à bulles, notre compréhension actuelle des effets des propriétés non-newtoniennes sur différents aspects hydrodynamiques des colonnes à bulles est loin d'être complète. Parmi les quelques études réalisées sur l'effet des propriétés rhéologiques de la phase liquide dans les colonnes de bulles, l'influence de l'élasticité du liquide sur les paramètres hydrodynamiques n'a jamais été étudiée distinctement et les modèles et concepts disponibles à l'heure actuelle sur ce sujet sont insuffisants pour une application industrielle. Afin d'obtenir un aperçu global de la performance des colonnes à bulles utilisant des liquides non-newtoniens, les effets de toutes les propriétés rhéologiques de la phase liquide, et non pas l'effet d'un seul paramètre qu'est la viscosité, doivent être étudiés. Cette thèse vii est donc dédiée à l'étude de l’hydrodynamique des colonnes à bulles fonctionnant avec des liquides non-newtoniens possédant des propriétés rhéologiques variées. Le principe de fonctionnement, les aspects hydrodynamiques de base du réacteur à colonne à bulles, ainsi que les liquides non-newtoniens et leurs propriétés rhéologiques sont brièvement discutés dans les deux premiers chapitres de cette thèse. Le premier objectif de ce travail est de comprendre l'effet des propriétés rhéologiques du liquide sur les différents paramètres hydrodynamiques d'une colonne à bulles. À cet égard, l'effet de la rhéologie de la phase liquide sur l'hydrodynamique d'un réacteur à colonne à bulles à l'échelle pilote est largement étudiée en sélectionnant stratégiquement divers types de liquides. La rétention de gaz et ses variations radiales et axiales, le point de transition du régime opératoire et la taille des bulles sont évalués au moyen de deux sondes à fibre optiques fabriquées dans nos laboratoires, ainsi que plusieurs capteurs de pression. Afin de mieux comprendre l'effet de la rhéologie sur les paramètres hydrodynamiques de la phase gazeuse, plusieurs analyses en fonction du temps et des fréquences sont réalisées sur les signaux de fluctuations de pression. Les effets visqueux et élastiques simultanés des liquides non-newtoniens sont étudiés à l'aide d'une nouvelle approche basée sur les modules dynamiques des solutions viscoélastiques. Il a été trouvé que la viscosité du liquide favorise la coalescence des bulles, alors que son élasticité l'entrave, se comportant comme un solide à l'interface de deux bulles. La présence d'élasticité dans le liquide mène à la réduction de la longueur de corde moyenne des bulles et à l’augmentation de la rétention globale de gaz. Les résultats obtenus dans cette partie du travail sont primordiaux afin d'atteindre le second objectif, qui vise principalement à étudier localement les paramètres hydrodynamiques et à développer de nouvelles corrélations pour estimer la taille des bulles et la rétention de gaz dans les réacteurs à colonne à bulles utilisant des liquides non-newtoniens. Par conséquent, dans la deuxième partie de ce travail, les propriétés locales des bulles telles que leur fréquence, leur longueur de corde et leur vitesse d'ascension ainsi que leurs distributions radiales et axiales, sont évaluées à l'aide de deux sondes à fibres optiques placées à des endroits différents dans le réacteur à colonne à bulles opéré avec différents liquides non-newtoniens. Il a été observé que le profil radial de la fréquence des bulles, de leur longueur de corde et de leur vitesse d'ascension sont relativement plats à basse vitesse superficielle de gaz, mais deviennent paraboliques lorsque la vitesse superficielle du gaz augmente. En outre, à l'aide d'une analyse adimensionnelle, deux corrélations ont été développées afin de prédire la taille des bulles et la rétention de gaz dans les colonnes à bulles opérées avec des liquides non-newtoniens. Ces viii deux nouvelles corrélations sont capables de prédire correctement la taille des bulles et la rétention de gaz au sein des colonnes à bulle, à l'aide du rapport entre modules dynamiques des solutions viscoélastiques. Une variété de procédés industriels tels que la synthèse de Fischer-Tropsch, la synthèse du méthanol, l'oxydation partielle de l'éthylène, l’hydrocraquage des résidus lourds, et l'hydroformylation utilise des colonnes à bulles, mais à haute pression. Par le passé, il a été découvert que la pression d'opération a un effet significatif sur les caractéristiques hydrodynamiques des colonnes à bulles. Par exemple, une augmentation de la pression opératoire conduit normalement à la formation de plus petites bulles au niveau du distributeur de gaz. Bien que l'étude des effets de la pression dans les colonnes à bulles ait fait l'objet de certains travaux de recherche, de nombreuses zones restent à éclairer et il existe encore un grand intérêt des chercheurs et des concepteurs de réacteurs à conduire des études approfondies afin d'élucider l'influence de la pression d'opération sur les différents aspects de l'hydrodynamique et, en conséquence, sur la performance de réacteurs à colonne à bulles. Afin d'optimiser les procédés industriels cités ci-dessus, il est indispensable d'avoir une compréhension complète de l'effet de la pression d'opération sur la cinétique chimique, les propriétés du liquide (viscosité et tension superficielle), le régime d'écoulement de liquide, la dynamique des bulles (taille des bulles, forme de la bulle, éclatement et taux de coalescence, vitesse d'ascension) et le taux de transfert de chaleur et de masse. Par conséquent, le dernier objectif de ce travail est consacré à étudier l'effet de la pression d'opération sur l'hydrodynamique de la colonne à bulles et en présence de liquides non-newtoniens. A cet effet, un ensemble de réacteurs à haute pression/ haute température, dont une colonne à bulles et un réacteur à lit fluidisé ont été conçus et construits. En plus des réacteurs en tant que tels, cette installation inclus différents équipements tels que des compresseurs, des cylindres de stockage de gaz à haute pression, des éléments chauffants, un réservoir d'alimentation de liquide, une pompe centrifuge pour liquide, des séparateurs gaz-liquide, une unité de contrôle, un système d'acquisition de données, etc. Cette installation expérimentale sera introduite plus en détails au Chapitre 5. Au sein de cette installation et à l'aide de mesures de signaux de pression différentiels et dynamiques, divers caractéristiques hydrodynamiques des colonnes à bulles, comme la rétention totale du gaz et sa distribution axiale, le point de transition de régime d'écoulement, les fluctuations de pression et son écart-type, ont été étudiées. La vitesse superficielle du gaz a été variée de 1 à 35 (cm s-1) couvrant les deux régimes ix d'écoulement, homogène et hétérogène. La pression de fonctionnement a également été variée de 0.1 à 1 (MPa) pendant les expériences. Il a été étudié que la rétention totale de gaz augmente à la fois avec la pression opératoire et avec l'élasticité de la phase liquide ; l'impact de la pression est d’autant plus prononcé à de basses pressions d'opération. Il a également été identifié que l'augmentation de la pression d’opération conduit à un décalage du point de transition entre régimes hydrodynamiques à de plus haute vitesses de gaz superficielles. En conclusion, il a été prouvé que non seulement la rhéologie de la phase liquide, mais également la pression d'opération, ont un effet important sur l'hydrodynamique des réacteurs à colonnes à bulles. Les connaissances scientifiques développées dans ce travail peuvent ainsi aider les industriels à mieux décrire les phénomènes présents dans les colonnes bulles utilisant des liquides non-newtoniens très visqueux et des pressions élevées, ce qui leur permettrait une conception, exploitation et mise à l’échelle plus avisée et performante des réacteurs à colonne à bulles commerciaux. ---------- Processes based on the contact between gas and liquid/slurry phases are commercially used for performing a variety of chemical reactions. Although different types of reactors are used for this purpose, bubble column reactors have received more attention during the past decade since they offer some unique advantages, such as ease of operation, high rates of heat and mass transfer, and lower maintenance costs due to the absence of moving parts. The design and scale-up of a bubble column reactor require a complete understanding of its complex hydrodynamics, which is influenced by the physical properties of the phases, the operating variables, and the design parameters. Current design procedures for bubble columns involve several steps of pilot-plant experimentation using equipment of different scales, which is expensive and time consuming. In recent years, the liquid and/or slurry phases which are processed in bubble columns in many applications are viscous and normally demonstrate non-Newtonian behaviors during the process operation. Hydroconversion of heavy oil and petroleum residues, wastewater treatment, processing of fermentation broths, polymer composite processing, and slurry-phase synthesis are some of those processes in which viscous and non-Newtonian liquids are often encountered in bubble column reactors. On the other hand, in bubble columns operating with non-Newtonian liquids, the viscosity changes upon the flow conditions, and also a variety of non-Newtonian liquids possess elastic properties that can affect and alter bubble behavior to a great extent. Although there has been an increasing application of non-Newtonian fluids in bubble column reactors, our present understanding of the effects of non-Newtonian properties on different hydrodynamic aspects of bubble columns is far from complete. Only few studies are reported on the effect of liquid phase rheological properties in bubble columns so that the influence of liquid elasticity on the hydrodynamic parameters such as gas holdup and bubble properties has never been studied distinctly, and the models and concepts currently available on this subject are insufficient for chemical practice. To gain adequate insight into the performance of bubble columns operating with non-Newtonian liquids, the effects of all rheological properties of the liquid phase need to be investigated rather that the effect of a single parameter like viscosity. This thesis is, therefore, dedicated to investigating the hydrodynamics of bubble columns operating with non-Newtonian liquids having different rheological properties. xi The operation principle and basic hydrodynamic aspects of the bubble column reactors, as well as non-Newtonian liquids and their rheological properties, are briefly discussed in the first two chapters. The first objective of this work is to understand the effect of the rheological properties of liquid on different hydrodynamic aspects of a bubble column reactor including gas holdup and its radial and axial distributions, bubble size and its axial distribution, standard deviation, power spectral density and average frequency of pressure signals. In this regard, the effect of liquid phase rheology on the hydrodynamics of a pilot-scale bubble column reactor is extensively investigated by strategically selecting various types of liquids. The selected liquids include water as a reference and low-viscosity liquid, an aqueous glucose solution as a highly viscous Newtonian and inelastic liquid, a Boger fluid which has a constant viscosity identical to the glucose solution but it is slightly elastic, and finally two non-Newtonian (shear-thinning) and elastic Carboxymethyl cellulose (CMC) and Xanthan gum solutions. Gas holdup and its radial and axial variations, the operating flow regime transition and bubble size are evaluated by means of two in-house made optical fiber probes and several pressure transducers. Different time-domain and frequency-domain analyses are applied to the pressure fluctuation signals in order to better understand the effect of liquid phase rheology on the gas holdup and bubble size. The simultaneous viscous and elastic effects of non-Newtonian liquids are studied by proposing a new approach based on the dynamic moduli of viscoelastic solutions. It was found that the viscosity of liquid is more favorable for bubble coalescence; however, the elasticity can hinder bubble coalescence as it can demonstrate a solid-like behavior at the interface of two bubbles. The presence of elasticity in the liquid was shown to reduce the average bubble chord length and increase the overall gas holdup. The results obtained in this part of the work are essential for achieving the second objective, which is aimed at studying the local hydrodynamic parameters such as local bubble frequency and bubble rise velocity and developing new correlations to estimate bubble size and gas holdup in bubble column reactors operating with non-Newtonian liquids. Therefore, in the second part of this work, local bubble properties such as bubble frequency, bubble chord length, and bubble rise velocity, as well as their radial and axial distributions, are evaluated by installing two optical fiber probes at various locations within a bubble column reactor operating with different non-Newtonian liquids. It was observed that the radial profiles of bubble frequency, bubble chord length and bubble rise velocity are relatively flat at low superficial gas velocities, while they become parabolic as the superficial gas velocity increases. Moreover, by applying the dimensional analysis, two new correlations are xii developed to predict the bubble size and gas holdup in bubble columns operating with non-Newtonian liquids. The two correlations are developed by taking into consideration the ratio between the dynamic moduli of viscoelastic solutions and are capable of accurately predicting both bubble size and gas holdup. Moreover, a variety of commercial processes such as Fischer-Tropsch synthesis, Methanol synthesis, Partial oxidation of ethylene, Residuum hydrotreating, and Hydroformylation are carried out in bubble columns at elevated pressures. The operating pressure is found to have a significant effect on the hydrodynamic characteristics of bubble columns such as bubble properties and gas holdup. For instance, an increase in the operating pressure normally results in the formation of smaller bubbles at the gas distributor and this is mainly due to the higher gas density at elevated pressure. Although investigating the pressure effects in the bubble columns has been the subject of some research, there is still a strong need toward more studies on the influence of operating pressure on different hydrodynamic aspects, and, accordingly, on the performance of bubble column reactors. Therefore, the last objective of this work is devoted to investigating the effect of operating pressure on the hydrodynamics of bubble column reactors in presence of non-Newtonian liquids. For this purpose, a high-pressure/high-temperature multiphase reactors unit including a bubble column reactor with an inner diameter of 0.152 m and a total height of 4.8 m has been designed and constructed to perform experiments at elevated pressures. The multiphase reactors unit was equipped with different equipment, including air compressors, high-pressure gas storage cylinders, gas heating elements, liquid supply tank, liquid centrifugal pump, gas-liquid separators, PLC control unit, etc. This experimental unit is introduced in more detail in Chapter 5. Various hydrodynamic characteristics of bubble column reactors, such as the total gas holdup and its axial distribution, operating flow regime transition point, pressure fluctuation and its standard deviation have been studied by means of pressure signal measurements with several differential and dynamic pressure traducers. The superficial gas velocity varied from 1 to 35 (cm s-1), covering both homogeneous and heterogeneous flow regimes. Operating pressure also changed from 0.1 to 1 (MPa) during the experiments. The total gas holdup was found to increase with both operating pressure and the elasticity of liquid phase, and the effect of pressure was shown to be more pronounced at lower operating pressures. The operating pressure was shown to shift the flow regime transition point to higher superficial gas velocities. A new correlation was also derived for predicting the gas holdup in bubble column reactors operating at elevated pressure. As a xiii conclusion, both the rheology of the liquid phase and operating pressure are shown to have important effects on the hydrodynamics of bubble column reactors. Moreover, the scientific findings of the present work may have significant implications for the more accurate design, operation and scale-up of commercial bubble column reactors, where highly viscous and non-Newtonian liquids and high pressures are often applied

Model-Robust Inference for Clinical Trials that Improve Precision by Stratified Randomization and Adjustment for Additional Baseline Variables

We focus on estimating the average treatment effect in clinical trials that involve stratified randomization, which is commonly used. It is important to understand the large sample properties of estimators that adjust for stratum variables (those used in the randomization procedure) and additional baseline variables, since this can lead to substantial gains in precision and power. Surprisingly, to the best of our knowledge, this is an open problem. It was only recently that a simpler problem was solved by Bugni et al. (2018) for the case with no additional baseline variables, continuous outcomes, the analysis of covariance (ANCOVA) estimator, and no missing data. We generalize their results in three directions. First, in addition to continuous outcomes, we handle binary and time-to-event outcomes; this broadens the applicability of the results. Second, we allow adjustment for an additional, preplanned set of baseline variables, which can improve precision. Third, we handle missing outcomes under the missing at random assumption. We prove that a wide class of estimators is asymptotically normally distributed under stratified randomization and has equal or smaller asymptotic variance than under simple randomization. For each estimator in this class, we give a consistent variance estimator. This is important in order to fully capitalize on the combined precision gains from stratified randomization and adjustment for additional baseline variables. The above results also hold for the biased-coin covariate-adaptive design. We demonstrate our results using completed trial data sets of treatments for substance use disorder, where adjustment for additional baseline variables brings substantial variance reduction

HIV, hepatitis C virus, and hepatitis B virus co-infections among injecting drug users in Tehran, Iran

SummaryObjectivesTo assess the prevalence of HIV, hepatitis B virus (HBV) and hepatitis C virus (HCV) infections and co-infections among injecting drug users (IDUs) in Tehran.MethodsA sample of 899 IDUs (861 male and 38 female) was recruited in Tehran from treatment and harm reduction facilities and from drug user hangouts in public areas in equal proportions. ELISA testing for HIV, HCV antibody (HCV-Ab), hepatitis B surface antigen (HBsAg), and hepatitis B core antibody (HBcAb) was carried out. Positive HIV tests were rechecked by Western blot.ResultsThe prevalence of HIV was 10.7%, HCV infection was 34.5%, and past or current HBV infection was 50.7%. Infection with all three viruses was seen in 6.5% (95% confidence interval 4.9–8.2) of participants. HIV/HCV, HIV/HBV, and HBV/HCV co-infections were seen in 8.7%, 7.8%, and 21.0% of participants, respectively. The rate of HCV infection among HIV-positive cases was significantly higher than in HIV-negative IDUs (80.6% vs. 28.7%, p<0.0001). There was no significant association between these infections and co-infections with gender and source of sampling.ConclusionIn general, co-infection with these three blood-borne viruses is common among IDUs. Since co-infection increases the morbidity and mortality of all infections, the observed level of co-infection in the high number of IDUs in Iran necessitates a serious comprehensive response

Towards estimation of CO₂ adsorption on highly porous MOF-based adsorbents using gaussian process regression approach

In recent years, new developments in controlling greenhouse gas emissions have been implemented to address the global climate conservation concern. Indeed, the earth's average temperature is being increased mainly due to burning fossil fuels, explicitly releasing high amounts of CO(2) into the atmosphere. Therefore, effective capture techniques are needed to reduce the concentration of CO(2). In this regard, metal organic frameworks (MOFs) have been known as the promising materials for CO(2) adsorption. Hence, study on the impact of the adsorption conditions along with the MOFs structural properties on their ability in the CO(2) adsorption will open new doors for their further application in CO(2) separation technologies as well. However, the high cost of the corresponding experimental study together with the instrument's error, render the use of computational methods quite beneficial. Therefore, the present study proposes a Gaussian process regression model with four kernel functions to estimate the CO(2) adsorption in terms of pressure, temperature, pore volume, and surface area of MOFs. In doing so, 506 CO(2) uptake values in the literature have been collected and assessed. The proposed GPR models performed very well in which the exponential kernel function, was shown as the best predictive tool with R(2) value of 1. Also, the sensitivity analysis was employed to investigate the effectiveness of input variables on the CO(2) adsorption, through which it was determined that pressure is the most determining parameter. As the main result, the accurate estimate of CO(2) adsorption by different MOFs is obtained by briefly employing the artificial intelligence concept tools

Apoptosis inhibition or inflammation: the role of NAIP protein expression in Hodgkin and non-Hodgkin lymphomas compared to non-neoplastic lymph node

<p>Abstract</p> <p>Background</p> <p>Inhibitors of Apoptosis (IAP) family play a critical role in apoptosis and inflammatory response. Neuronal Apoptosis Inhibitory Protein (NAIP), as a member of both IAPs and NLR families (NOD-Like Receptor), is a unique IAP harboring NOD (Nucleotide Oligomerization Domain) and LLR (Leucine Rich Repeat) motifs. Considering these motifs in NAIP, it has been suggested that the main function of NAIP is distinct from other members of IAPs. As a member of NLR, NAIP mediates the assembly of 'Inflammasome' for inflammatory caspase activation. Pathologic expression of NAIP has been reported not only in some infectious and inflammatory diseases but also in some malignancies. However, there is no report to elucidate NAIP expression in lymphomatic malignancies.</p> <p>Methods</p> <p>In this study, we examined <it>NAIP </it>protein expression in 101 Formalin-Fixed Paraffin-Embedded blocks including samples from 39 Hodgkin Lymphoma and 23 Non Hodgkin Lymphoma cases in comparison with 39 control samples (30 normal and 9 Reactive Lymphoid Hyperplasia (RLH) lymph nodes) using semi-quantitative immuno-flourecent Staining.</p> <p>Results</p> <p>NAIP expression was not statistically different in lymphoma samples neither in HL nor in NHL cases comparing to normal samples. However, we evaluated NAIP expression in normal and RLH lymph nodes. Surprisingly, we have found a statistically significant-difference between the NAIP expression in RLH (M.R of NAIP/GAPDH expression = 0.6365 ± 0.017) and normal lymph node samples (M.R of NAIP/GAPDH expression = 0.5882 ± 0.047) (<it>P </it>< 0.01).</p> <p>Conclusions</p> <p>These findings show that the regulation of apoptosis could not be the main function of NAIP in the cell, so the pathologic expression of NAIP is not involved in lymphoma. But, we concluded that the over expression of NAIP has more effective role in the inflammatory response. Also, this study clarifies the NAIP expression level in lymphoma which is required for IAPs profiling in order to be used in potential translational applications of IAPs.</p