Journal articles on the topic 'Modèle Darcy'

Les transferts d'eau dans le sol sont généralement, pour des raisons de facilité, supposés se dérouler dans des conditions isothermes. Les modèles proposés couplant les transferts hydriques et thermiques se heurtent aux difficultés inhérentes à la détermination des coefficients de transfert. Disposant de l'évolution de la température, de la succion et de la teneur en eau dans les profils du sol de lysimètre, une comparaison portant sur l'importance des gradients hydriques et thermiques dans le transfert d'eau en phases liquide et vapeur a été menée. Il se dégage clairement, que dans le domaine de teneurs en eau qui intéressent l'agronome (teneur en eau supérieure à celle au point de flétrissement), l'essentiel des transferts se fait via la phase liquide. En effet, les flux dus aux gradients de teneur en eau dépassent d'au moins deux ordres de grandeur les flux induits par les gradients de température. Ce qui confirme bien la validité des équations de Darcy-Richards (DARCY, 1856; RICHARDS, 1931) où l'effet de température est négligé.

Environmental concern has encouraged development related to polluted water treatment. Produced water originated from oil exploration has been submitted to different separation processes such as settling tanks, floaters, two-phase and three-phase separators, hydrocyclones, and membranes. On the use of membranes, the goal is to separate soluble components from solutions based on the size, charge, shape, and molecular interactions between the solute and membrane surface. In the present work, a numerical study was developed on the oil-water mixture separation process using a porous ceramic membrane module. The mathematical model used in this research is composed of mass and momentum conservation equations coupled to Darcy ́s law and SST k-ω turbulence model. Simulations were carried out employing the Ansys CFX commercial software. Results of the pressure, velocity, oil concentration distribution inside the device and membrane are presented and discussed. The results showed that the geometric aspects of the proposed microfiltration module and the membrane distribution within the separation module had a significant influence on the hydrodynamic flow leading to polarized layer dispersion.

The contradiction between supply and demand of energy leads to more and more attention on the large-scale energy storage technology; Compressed Air Energy Storage (CAES) technology is a new energy storage technology that is widely concerned in the world. The research of coupled heat transfer and seepage in fractured surrounding rocks is the necessary basis to evaluate the operation safety and effectiveness of CAES. Current studies point to the possibility of cracking in concrete liner seals, but the thermodynamic processes and leakage characteristics of compressed air in the presence of cracking and the heat transfer characteristics of seepage have not been addressed and reported. In order to investigate the leakage, the gas seepage and heat transfer law in fractured rock when the hard rock CAES gas reservoir seal cracks, the COMSOL fracture Darcy module, and the non-Darcy Forchheimer model are used as the constitutive seepage. The global ODE is used to calculate the thermodynamic process of compressed air in gas storage with coupled seepage and heat transfer process. The pressure and temperature of compressed air are obtained as the unsteady boundary of the seepage heat transfer model. A program for calculating the seepage and heat transfer characteristics of fractured surrounding rock in the CAES gas reservoir is established. On this basis, with the proposed Suichang CAES cavern as the background, the seepage and heat transfer characteristics of the fractured surrounding rock of the gas storage are studied. The results showed that when there are fewer cracks in the lining and surrounding rock of the air reservoir, the air pressure decreases due to a small amount of air leakage after 30 operation cycles, and the leakage rate of each cycle is 0.7% of the gas storage capacity, but it still meets the engineering requirements. If the plant is operating under these conditions, the charging rate will need to be increased by 1.2 kg/s per cycle charging stage. In the discharging and power generation phase, the high-pressure air that previously percolated into the rock mass cracks could flow back into the air storage through the lining cracks. Therefore, it is incorrect and unreliable to consider the gas which flows out from the inner surface of the lining as unusable. When the lining crack width is less than 0.3 mm, the seepage flow is Darcy flow and the non-Darcy effect can be ignored; when the lining crack width is greater than 0.5 mm, the non-Darcy effect of seepage cannot be ignored. The gas velocity in the surrounding rock fracture medium is on the order of 0.01 m/s with an influence range of over 100 m, and the gas velocity in the pore medium is on the order of 10-6 m/s with an influence range of 50 m. The findings of this study contribute to a better understanding of the interaction between the thermodynamic properties of compressed air and the seepage heat transfer process in compressed air storage underground reservoirs, as well as the gas leakage process in the event of liner seal cracking.

RESUMO: A crítica brasileira sempre se preocupou com a questão da autonomia das literaturas brasileira e latino-americana, dividindo-se, como a própria literatura, entre os pólos do modelo e da cópia, da continuidade e da ruptura. Este trabalho busca reler alguns textos-críticos, associando-os a obras literárias que têm como objeto o índio – Alencar, Darci Ribeiro e Vargas Llosa –, bem como às histórias contadas diretamente por um índio. Nesse percurso, busca-se refletir sobre o lado índio da literatura latino-americana em diálogo com suas outras facetas, explicitando a contradição inerente ao processo.RÉSUMÉ: La question de l'autonomie des littératures brésiliennes et latino-américaine a toujours préocupé la critique brésilienne, ce qui l'a fait se partager, tout comme la littérature elle-même, entre les faces du modèle et da la copie, entre celles de la continuité et de la rupture. Ce travail cherche à relire quelques textes critiques, en les faisant s'associer à des oeuvres littéraires dont 1'objet est constitué par 1'indien – Alencar, Darci Ribeiro et Vargas Llosa –, aussi bien qu'aux histoires racontées par un indien. On a tâché, chemin faisant, de réfléchir au côté indien de la littérature latino-américaine nous tournant vers le dialogue avec ses autres aspects, pour éclairer la contradiction inhérente au procès.

Commercial hemodialyzers are hollow-fiber cylindrical modules with dimensions and inlet–outlet configurations dictated mostly by practice. However, alternative configurations are possible, and one may ask how they would behave in terms of performance. In principle, it would be possible to depart from the standard counter-flow design, while still keeping high clearance values, thanks to the increase in the shell-side Sherwood number (Sh) due to the cross-flow. To elucidate these aspects, a previously developed computational model was used in which blood and dialysate are treated as flowing through two interpenetrating porous media. Measured Darcy permeabilities and mass transfer coefficients derived from theoretical arguments and CFD simulations conducted at unit-cell scale were used. Blood and dialysate were alternately simulated via an iterative strategy, while appropriate source terms accounted for water and solute exchanges. Several module configurations sharing the same membrane area, but differing in overall geometry and inlet–outlet arrangement, were simulated, including a commercial unit. Although the shell-side Sherwood number increased in almost all the alternative configurations (from 14 to 25 in the best case), none of them outperformed in terms of clearance the commercial one, approaching the latter (257 vs. 255 mL/min) only in the best case. These findings confirmed the effectiveness of the established commercial module design for the currently available membrane properties.

In the paper on the basis of Darcy equations defining a lubricant flow in porous layers and modified Reynolds equation is solved a problem of unsteady flow of viscous incompressible lubricant in the gap of a doublelayer porous damper. A case is considered when permeability in porous layers changes according to a normal low, and a combined feed of lubricant is carried out simultaneously in axial and radial directions. As a result of the solution of the problem specified there is found a field of pressures in porous layers and a lubrication layer, there are also obtained analytical dependences for efforts in an oil film, a module of unbalance transmitted force and also stationary and transitional transfer ratios are determined. It is proved that the combined lubricant feed a damper functions more stably, than at a separate axial and radial its feed. The obtained specified calculated models allowed determining the efficiency of additional factors account, and also carrying out a comparative analysis of results newly obtained and already available that defined a larger proximity of a new model to real practice.

In the work on the basis of Darcy equations defining lubricant flow in porous layers, and of Reynolds modified equation the problem of an unsteady motion of viscous incompressible lubricant in the gap of a por-ous damper is under solution. A case is under consideration when a forced lubricant supply is carried out in circumferential and radial directions taking into account the influence of orthogonal anisotropy of a porous layer. As a result of the solution of the problem specified there is found a field of pressures in a porous and lubricating layer, and analytical dependences for efforts in an oil film are obtained. Besides, there is defined a module of an unbalance transmitted effort and also stationary and transient ratios of transfer. It is proved that at the forced lubricant feed in a circumferential or radial direction taking into account the influence of orthogonal anisotropy of a porous layer, a damper functions more steadily. The obtained specified calculated models al-lowed defining a number of supplementary factors and also carrying out a comparative analysis of results newly obtained and already existing ones. It confirmed a larger proximity of a new model an actual practice.

Zona Pellucida Like Domain 1 Protein (ZPLD1) is a main component of the cupula, a gelatinous structure located in the labyrinth organ of the inner ear and involved in vestibular function. The N-glycosylated protein is likely able to organize high-molecular-weight polymers via its zona pellucida (ZP) module, which is common for many extracellular proteins that self-assemble into matrices. In this work, we confirmed that ZPLD1 can form multimers while setting up a cellular model leveraging Madin–Darby canine kidney (MDCK) cells to study protein polymerization. We identified two motifs within ZPLD1 which regulate its polymerization and follow previously published conserved regions, identified across ZP proteins. Mutational depletion of either one of these modules led to diminished or abnormal polymer formation outside of the cells, likely due to altered processing at the plasma membrane. Further, intracellular polymer formation was observed. Proteolytic cleavage during secretion, separating the regulatory motif located distinct of the ZP module from the mature monomer, seems to be necessary to enable polymerization. While the molecular interactions of the identified motifs remain to be proven, our findings suggest that ZPLD1 is a polymer forming ZP protein following an orchestrated mechanism of protein polymerization to finally build up a gelatinous hydrogel.

This work focused on the computational fluid dynamics (CFD) modeling of H2/N2 separation in a membrane permeator module containing a supported dense Pd-based membrane that was prepared using electroless pore-plating (ELP-PP). An easy-to-implement model was developed based on a source–sink pair formulation of the species transport and continuity equations. The model also included the Darcy–Forcheimer formulation for modeling the porous stainless steel (PSS) membrane support and Sieverts’ law for computing the H2 permeation flow through the dense palladium film. Two different reactor configurations were studied, which involved varying the hydrogen flow permeation direction (in–out or out–in). A wide range of experimental data was simulated by considering the impact of the operating conditions on the H2 separation, such as the feed pressure and the H2 concentration in the inlet stream. Simulations of the membrane permeator device showed an excellent agreement between the predicted and experimental data (measured as permeate and retentate flows and H2 separation). Molar fraction profiles inside the permeator device for both configurations showed that concentration polarization near the membrane surface was not a limit for the hydrogen permeation but could be useful information for membrane reactor design, as it showed the optimal length of the reactor.

Domestic and industrial hydraulic drainage networks have gradually become more complicated because of the cities’ rapid expansion. In surcharged hydraulic systems, the head losses may become rather significant, and should not be neglected because could result in several problems. This work presents an investigation about major and minor head losses in a hydraulic flow circuit, simulating the water transport in a drainage network at room temperature (298.15 K) under atmospheric pressure (101,325 Pa). The losses produced by the fluid viscous effect through the one used cast-iron rectilinear pipe (RP-11) and the localized losses generated by two flow appurtenances, one fully open ball valve (BV-1) and one module of forty-four 90º elbows (90E-8) were experimentally measured. Experimental data generated head-loss curves and their well fitted to potential regressions, displaying correlation coefficients (R2) of 0.9792, 0.9924, and 0.9820 for BV-1, 90E-8, and RP-11, respectively. Head loss experimental equations and local loss coefficients through BV-1 and 90E-8 were determined successfully. The Moody’s diagram application proved to be a quite appropriate tool for an approximate estimation of Darcy-Weisbach friction factor. A good approximation between friction factor values obtained via experimental measurements and the Moody’s diagram was observed with mean absolute deviate of 0.0136.

In this study, a mathematical model has been developed for the submerged membrane bioreactor (SMBR). Polyvinyl alcohol (PVA) Modified Non-woven model is immerged in MBR to be used for synthetic wastewater treatment. The results show that membrane fouling resistance is mostly cake resistance occurring during filtration. Based on the concept of specific fouling resistance and Darcy law that describes the relationship between flux and resistance during filtration driven by pressure, a module is established to explain the relationship between specific fouling resistance and time during filtration controlled by cake resistance in SMBR. The decline trend of flux can be predicted by the model. The model is used to predict the decline trend of flux during pharmaceutical wastewater treatment. Compared with experimental data, the relative error is less than 10% at t>b, the relative error is less than 5% at t>2b. It shows that the model can predict the decline trend of flux during stable operation of SMBR. But the relative error is bigger during unstable operation at initial stage (t<b). The model developed in this study would provide a useful tool in optimizing operation conditions as well as design parameters for a SMBR system.

In this study, steady-state three-dimensional turbulent forced convection flow and heat transfer characteristics in a circular pipe with baffles attached inside pipe have been numerically investigated under constant wall heat flux boundary condition. Numerical study has been carried out for Reynolds number Re of 3000-50,000, Prandtl number Pr of 0.71, baffle distances s/D of 1, 2, and 3, and baffle angle a of 30o-150o. Ansys Fluent 12.0.1 software has been used to solve the flow field. It is observed that circular pipe having baffles has a higher Nusselt number and friction factor compared to the smooth circular pipe without baffles. Maximum Nusselt number and friction factor are obtained for the baffle angle of 90o. Nusselt number increases while baffle distance increases in the range of studied; however, friction factor decreases. Periodically fully developed conditions are obtained after a certain module. Thermal performance factor increases with increasing baffle distance in the rage of studied but decreases with increasing Reynolds number; maximum thermal performance factor is obtained for the baffle angle of 150?. Results show that baffle distance, baffle angle, and Reynolds number play important role on both flow and heat transfer characteristics. The accuracy of the results obtained in this study is verified by comparing the results with those available in the literature for smooth circular pipes. All the numerical results are correlated within accuracy of ?10 and ?15% for average Nusselt number and Darcy friction factor, respectively.

The heavy-oil flow in porous media is characterized by non-Darcy law with variable threshold pressure gradient (TPG) due to the large fluid viscosity. However, available analytical and numerical models hardly consider this effect, which can lead to erroneous results. This paper is aimed at presenting an innovative approach and establishing a numerical simulator to analyze the heavy-oil flow behavior with waterflooding. The apparent viscosity of the oil phase and flow correction coefficient characterized by the TPG were applied to describe the viscosity anomaly of heavy oil. Considering the formation heterogeneity, the TPG was processed into a variable related to mobility and the directionality. The discretization and linearization of the mathematical model were conducted to establish a fully implicit numerical model; the TPG value on each grid node was obtained through oil phase mobility interpolation, and then, the Jacobi matrix was reassembled and calculated to solve pressure and saturation equations. The corresponding simulator was thus developed. The pre-/postprocessing module of the simulator is connected to ECLIPSE; then, an efficient algorithm is introduced to realize a fast solution. Results show that considering the TPG will not only reduce the waterflooding area but also reduce the oil displacement efficiency because of aggravating the nonpiston phenomenon and interlayer conflict. The numerical simulation study on the TPG of heavy oil provides theoretical and technical support for the rational development and adjustment of water-driven heavy oil.

Geotechnical engineering participates in the act of construction, which means that it must meet a double concern for securityand economy. Therefore, an essential part of the engineer's responsibility rests on the recognition of soils in order to determine their nature and properties (taking into account the flow of water). In the present work, we measure the swelling and the permeability by detection of the swelling, by our new optical method based on the interferometry-laser, invented by Hassan Asselman, within the team of Optics and photonics of sciences faculty, Tetouan-Morocco. This new prototype allows us to directly measure the following parameters: the permeability k (m / s), the Young module Eand the swelling index Cs. For the latter parameter, the evolution of the strain as a function of the stresses ρ (Pa) is measured for a given degree of saturation (Until saturation). Moreover, we will use the classical odometer test, which reproduces the conditions of deformation of the soils. Using the results of the latter by the graphic methods of Taylor and Gasagrande, it is possible to determine the value of the coefficient of consolidation of the soil Cv. According to the Darcy theoretical modelfor a saturated medium, Cv depends on the permeability, the compressibility coefficient mv (or the inverse of the model of Young odometric) and the voluminal weight of the water γw. These tests will be carried out at the GEORET Geotechnical Laboratory in Tetouan. To perform this work, we chose a sample of claydistrubed, already characterized by X-ray diffraction (whose clay fraction is illite). It is extracted from the so-called "Teffalin" quarry of the Tetouan region, used in the manufacture of pottery. Finally we give a comparison between our new patented method and the classic Odometric test

Anchorage removal like growth factor removal induces apoptosis. In the present study we have characterized signaling pathways that can prevent this cell death using a highly growth factor– and anchorage-dependent line of lung fibroblasts (CCL39). After anchorage removal from exponentially growing cells, annexin V-FITC labeling can be detected after 8 h. Apoptosis was confirmed by analysis of sub-G1 DNA content and Western blotting of the caspase substrate poly (ADP-ribose) polymerase. Growth factor withdrawal accelerates and potentiates suspension-induced cell death. Activation of Raf-1 kinase in suspension cultures of CCL39 or Madin–Darby canine kidney cells stably expressing an estrogen-inducible activated–Raf-1 construct (ΔRaf-1:ER) suppresses apoptosis induced by growth factor and/or anchorage removal. This protective effect appears to be mediated by the Raf, mitogen- or extracellular signal–regulated kinase kinase (MEK), and mitogen-activated protein kinase module because it is sensitive to pharmacological inhibition of MEK-1 and it can be mimicked by expression of constitutively active MEK-1 in CCL39 cells. Finally, apoptosis induced by disruption of the actin cytoskeleton with the Rho-directed toxin B (Clostridium difficile) is prevented by activation of the ΔRaf-1:ER chimeric construct. These findings highlight the ability of p42/p44 mitogen-activated protein kinase to generate survival signals that counteract cell death induced by loss of matrix contact, cytoskeletal integrity, and extracellular mitogenic factors.

The conducted researches have the purpose to develop the optimum approach which allows us to correctly estimate the hydrogeological conditions of buiding sites. The general patterns of formation, distribution and movement of groundwater within the sections of the planned and existing buildings and adjacent territories for Kyiv as an example were studied. For the study area and similar sites with complex hydrogeological conditions, which are caused by the alternation in section and in terms of layers of unsteady thickness with different filtration coefficients, it is more appropriate to use the method of mathematical modeling of geofiltration for predictive calculations. Since there is no detailed hydrogeological map of the site, it is advisable to build a natural hydrogeological model on the basis of engineering and geological survey data (groundwater levels data) for different periods reproducted by GIS. The obtained results make it possible to justify the mathematical model and to perform predictive modeling with sufficient accuracy for technogenically disturbed territories. The application of mathematical modeling allows avoiding unnecessary rough schematization of natural hydrogeological conditions, taking into account the complexity and diversity of boundary groundflow conditions, and thus give more realistic assessment of engineering measures impact on hydrogeological conditions of the territory. In order to take into account the patterns of formation, distribution and movement of groundwater for territories with dense urban development it is advisable, according to the authors, to simulate processes geofiltration according to the scheme given in this article. At the same time, the creation of scientifically sound mathematical and cartographic space-time natural hydrogeological model of the territory is the defining moment for further modeling. Application of Darcy Flow module of ArcGIS software enables to detect and specificate groundwater flow recharge and discharge conditions. This makes it possible, on the one hand, to avoid unnecessary schematization of natural hydrogeological conditions, and on the other hand, to take into account the complexity and diversity of groundflow boundary conditions, to give a more realistic assessment of possible engineering measures impact on the hydrogeological conditions of the territory during the construction.

Constitutive activation of the MAPK/ERK kinase (MEK)1-ERK2 signaling module in Madin-Darby canine kidney (MDCK)-C7 cells disrupts their ability to form cystlike structures in collagen gels and induces an invasive, myofibroblastlike phenotype. However, the reversibility of these cellular events, as well as the relative role of both MEK isoforms (MEK1 and MEK2) and both ERK isoforms (ERK1 and ERK2) during these processes, has not yet been investigated. We now report that loss of constitutively active MEK1 (caMEK1) and, thus, loss of active ERK1/2 in C7caMEK1 cells is associated with increased MEK2 protein expression, reexpression of ERK1 protein, and epithelial redifferentiation of these cells. The morphological changes toward an epithelial phenotype in these revertant cell lines (C7rev4, C7rev5, C7rev7) are reflected by the upregulation of epithelial marker proteins, such as E-cadherin, β-catenin, and cytokeratin, by the loss of α-smooth muscle actin expression, and by the ability of these epithelial revertants to form well-organized spherical cysts when grown in three-dimensional collagen gels. Further evidence for a role of the MEK1-ERK1/2 module in epithelial-mesenchymal transition was obtained from the analysis of two novel, spontaneously transdifferentiated MDCK-C7 cell clones (C7e1 and C7e2 cells). In these clones, increased MEK1/2-ERK1/2 phosphorylation, reduced MEK2 protein expression, and loss of ERK1 protein expression is associated with phenotypic alterations similar to those observed in transdifferentiated C7caMEK1 cells. C7e1 cells at least partially regained some of their epithelial characteristics at higher passages. In contrast, C7e2 cells maintained a transdifferentiated phenotype at high passage, were unable to generate cystlike epithelial structures, and retained invasive properties when grown on a three-dimensional collagen matrix. We conclude that in renal epithelial MDCK-C7 cells, stable epithelial-to-mesenchymal transition (EMT) is associated with loss of ERK1 protein expression, reduced MEK2 protein expression, and increased basal ERK2 phosphorylation. In contrast, loss of active MEK1-ERK1/2 results in increased MEK2 protein expression and reexpression of ERK1 protein, concomitant with the restoration of epithelial phenotype and the ability to form cystic structures.

Summary Single-well chemical tracer (SWCT) is the most commonly used field method to determine oil or water saturation in one-well enhanced-oil-recovery (EOR) pilots. Because hydrolysis of an ester, which is the main part of the method, leads to forming acid as well as alcohol, the equilibrium state of the reservoir is disturbed, and thus the pH changes. It is generally accepted that the hydrolysis-reaction rate is mainly dependent on the pH and temperature. Therefore, it is required to know the extent to which this dependency might affect the shape of the product-tracer profiles and the numerical interpretation of the field-test data for computing residual oil saturation (Sor). In this study, this notion has been investigated by coupling a multiphase-flow simulator to the geochemistry package PHREEQC (Parkhust and Appelo 2013). In this study, the PHREEQC geochemical simulator has been used to illustrate the extent to which different parameters might affect the pH variation during the test. The PHREEQC database has been modified to take the ester-hydrolysis reaction into account by adding the ester, alcohol, and acid-product species. The hydrolysis-reaction mechanisms of ester have also been programmed to account for the dependency of the hydrolysis reaction on the pH. Also, because ester partitions into the oil phase and travels behind the water phase (i.e., Darcy velocity), performing two-phase flow would be necessary to highlight the significance of the pH dependency of the hydrolysis-reaction rate on the tracer profiles. For doing that, a multiphase Buckley-Leverett (BL) flow simulation is coupled with IPhreeqc, which is an open-source module of the PHREEQC geochemical package. Then, a California Turbidite SWCT test has been re-evaluated to verify the approach. At the end, the geochemistry of a reservoir with an almost weak resistance (high temperature and weak buffer capacity) against pH variation in the SWCT test has been studied using the geochemical-based approach. The results show that the variation of the hydrolysis rate with pH could affect mainly the tail edge of the predicted tracer profiles, and it could marginally affect the apex of the profiles; however, it might affect the interpreted value of the Sor measurement as the resistance against pH variation becomes weaker. In these conditions, adapting the SWCT-test designs (i.e., shut-in time and injecting lower concentration of ester) could diminish the pH variation. The pH dependency of the hydrolysis-reaction rate is recommended for the numerical interpretation of the field SWCT-test data. The results of this study can be used to minimize the uncertainties of the SWCT tests and to improve the reliability of the Sor measurements.

International audience We propose a numerical model for the flow of a single phase,incompressible fluid in a porous medium with fractures. In this model, the flow obeys Forchheimer's law in the fracture and Darcy's law in the rock matrix. Nous proposons un modèle numérique d'un écoulement monophasique d'un fluide incompressible dans un milieu poreux fracturé. Les lois d'écoulement sont celle de Forchheimer dans la fracture et de Darcy dans la matrice rocheuse.

Selective protein distribution on distinct plasma membranes is important for epithelial cell function. To date, how proteins are directed to specific epithelial cell surface is not fully understood. Here we report a conserved DSSDE motif in LDL-receptor (LDLR) modules of corin (a transmembrane serine protease) and CD320 (a receptor for vitamin B12 uptake), which regulates apical membrane targeting in renal epithelial cells. Altering this motif prevents specific apical corin and CD320 expression in polarized Madin–Darby canine kidney (MDCK) cells. Mechanistic studies indicate that this DSSDE motif participates in a Rab11a-dependent mechanism that specifies apical sorting. In MDCK cells, inhibition of Rab11a, but not Rab11b, expression leads to corin and CD320 expression on both apical and basolateral membranes. Together, our results reveal a novel molecular recognition mechanism that regulates LDLR module-containing proteins in their specific apical expression in polarized renal epithelial cells.

Innovative approach to designing an integrated packaged andmodular hybrid energy plant allows for improved reliability, redun-dancy and ef ficiency. Austin Energy, who will own and operate thisplant, selected Burns & McDonnell as their packaged plant integrator.Austin Energy has signed an energy services agreement to provide thenew hospital with power, chilled water and steam.The plant is the first of its kind in the State of Texas using theCHP module to generate primary power for the Dell Children’s Medi-cal Center of Central Texas with the grid providing backup power. Thepackaged and modular CHP plant will utilize the state-of-the-art SolarTurbines Mercury 50 combustion turbine, which has a simple cycle heatrate ef ficiency of 38 percent and produces less than 5 ppm NO x andmeets the Texas 2005 emission mandate without the need for a catalyst,counting the thermal bene fits of steam and chilled water. In addition,the hybrid plant will utilize a heat recovery steam generator, packagedchiller plant and boiler, absorption cooling and thermal energy storageto maximize system ef ficiency, operational flexibility and reliability ofservices to the hospital and the campus district cooling system. The hybrid energy plant control system will allow the system tobe remotely monitored and operated from an off-site operational controlcenter. This article will provide insight into the design of the hybridenergy plant and present features and bene fits to this type of packagedand modular system approach. In addition to hospitals that have a needfor grid independence, universities, airports, and other critical facilities,such as data centers, will bene fit from this type of packaged hybridenergy plant approach.

In Australian universities, many courses provide lecture notes as a standard learning resource; however, captions and transcripts of these lectures are not usually provided unless requested by a student through dedicated disability support officers (Worthington). As a result, to date their use has been limited. However, while the requirement for—and benefits of—captioned online lectures for students with disabilities is widely recognised, these captions or transcripts might also represent further opportunity for a personalised approach to learning for the mainstream student population (Podszebka et al.; Griffin). This article reports findings of research assessing the usefulness of captioned recorded lectures as a mainstream learning tool to determine their usefulness in enhancing inclusivity and learning outcomes for the disabled, international, and broader student population.Literature ReviewCaptions have been found to be of benefit for a number of different groups considered at-risk. These include people who are D/deaf or hard of hearing, those with other learning difficulties, and those from a non-English speaking background (NESB).For students who are D/deaf or hard of hearing, captions play a vital role in providing access to otherwise inaccessible audio content. Captions have been found to be superior to sign language interpreters, note takers, and lip reading (Stinson et al.; Maiorana-Basas and Pagliaro; Marschark et al.).The use of captions for students with a range of cognitive disabilities has also been shown to help with student comprehension of video-based instruction in a higher education context (Evmenova; Evmenova and Behrmann). This includes students with autism spectrum disorder (ASD) (Knight et al.; Reagon et al.) and students with dyslexia (Alty et al.; Beacham and Alty). While, anecdotally, captions are also seen as of benefit for students with attention deficit hyperactivity disorder (ADHD) (Kent et al.), studies have proved inconclusive (Lewis and Brown).The third group of at-risk students identified as benefiting from captioning recorded lecture content are those from a NESB. The use of captions has been shown to increase vocabulary learning (Montero Perez, Peters, Clarebout, and Desmet; Montero Perez, Van Den Noortgate, and Desmet) and to assist with comprehension of presenters with accents or rapid speech (Borgaonkar, 2013).In addition to these three main groups of at-risk students, captions have also been demonstrated to increase the learning outcomes for older students (Pachman and Ke, 2012; Schmidt and Haydu, 1992). Captions also have demonstrable benefits for the broader student cohort beyond these at-risk groups (Podszebka et al.; Griffin). For example, a recent study found that the broader student population utilised lecture captions and transcripts in order to focus, retain information, and overcome poor audio quality (Linder). However, the same study revealed that students were largely unaware about the availability of captions and transcripts, nor how to access them.MethodologyIn 2016 students in the Curtin University unit Web Communications (an introductory unit for the Internet Communications major) and its complementary first year unit, Internet and Everyday Life, along with a second year unit, Web Media, were provided with access to closed captions for their online recorded lectures. The latter unit was added to the study serendipitously when its lectures were required to be captioned through a request from the Curtin Disability Office during the study period. Recordings and captions were created using the existing captioning system available through Curtin’s lecture recording platform—Echo360. As well as providing a written caption of what is being said during the lectures, this system also offers a sophisticated search functionality, as well as access to a total transcript of the lecture. The students were provided access to an online training module, developed specifically for this study, to explain the use of this system.Enrolled Curtin students, both on-campus and online, Open Universities Australia (OUA) students studying through Curtin online, teaching staff, and disability officers were then invited to participate in a survey and interviews. The study sought to gain insights into students’ use of both recorded lectures and captioned video at the time of the survey, and their anticipated future usage of these services (see Kent et al.).A total of 50 students—of 539 enrolled across the different instances of the three units—completed the survey. In addition, five follow-up interviews with students, teaching staff, and disability support staff were conducted once the surveys had been completed. Staff interviewed included tutors and unit coordinators who taught and supervised units in which the lecture captions were provided. The interviews assessed the awareness, use, and perceived validity of the captions system in the context of both learning and teaching.ResultsA number of different questions were asked regarding students’ demographics, their engagement with online unit materials, including recorded lectures, their awareness of Echo360’s lecture captions, as well as its additional features, their perceived value of online captions for their studies, and the future significance of captions in a university context.Of the 50 participants in the survey, only six identified themselves as a person with a disability—almost 90 per cent did not identify as disabled. Additionally, 45 of the 50 participants identified English as their primary language. Only one student identified as a person with both a disability and coming from a NESB.Engagement with Online Unit Materials and Recorded LecturesThe survey results provide insight into the ways in which participants interact with the Echo360 lecture system. Over 90 per cent of students had accessed the recorded lectures via the Echo360 system. While this might not seem notable at first, given such materials are essential elements of the units surveyed, the level of repeated engagement seen in these results is important because it indicates the extent to which students are revising the same material multiple times—a practice that captions are designed to facilitate and assist. For instance, one lecture was recorded per week for each unit surveyed, and most respondents (70 per cent) were viewing these lectures at least once or twice a week, while 10 per cent were viewing the lectures multiple times a week. Over half of the students surveyed reported viewing the same lecture more than once. Out these participants, 19 (or 73 per cent) had viewed a lecture twice and 23 per cent had viewed it three times or more. This illustrates that frequent revision is taking place, as students watch the same lecture repeatedly to absorb and clarify its contents. This frequency of repeated engagement with recorded unit materials—lectures in particular—indicates that students were making online engagement and revision a key element of their learning process.Awareness of the Echo360 Lecture Captions and Additional FeaturesHowever, while students were highly engaged with both the online learning material and the recorded lectures, there was less awareness of the availability of the captioning system—only 34 per cent of students indicated they were aware of having access to captions. The survey also asked students whether or not they had used additional features of the Echo360 captioning system such as the search function and downloadable lecture transcripts. Survey results confirm that these features were being used; however, responses indicated that only a minority of students using the captions system used these features, with 28 per cent using the search function and 33 per cent making use of the transcripts. These results can be seen as an indication that additional features were useful for revision, albeit for the minority of students who used them. A Curtin disability advisor noted in their interview that:transcripts are particularly useful in addition to captions as they allow the user to quickly skim the material rather than sit through a whole lecture. Transcripts also allow translation into other languages, highlighting text and other features that make the content more accessible.Teaching staff were positive about these features and suggested that providing transcripts saved time for tutors who are often approached to provide these to individual students:I typically receive requests for lecture transcripts at the commencement of each study period. In SP3 [during this study] I did not receive any requests.I feel that lecture transcripts would be particularly useful as this is the most common request I receive from students, especially those with disabilities.I think transcripts and keyword searching would likely be useful to many students who access lectures through recordings (or who access recordings even after attending the lecture in person).However, the one student who was interviewed preferred the keyword search feature, although they expressed interest in transcripts as well:I used the captions keyword search. I think I would like to use the lecture transcript as well but I did not use that in this unit.In summary, while not all students made use of Echo360’s additional features for captions, those who did access them did so frequently, indicating that these are potentially useful learning tools.Value of CaptionsOf the students who were aware of the captions, 63 per cent found them useful for engaging with the lecture material. According to one of the students:[captions] made a big difference to me in terms on understanding and retaining what was said in the lectures. I am not sure that many students would realise this unless they actually used the captions…I found it much easier to follow what was being said in the recorded lectures and I also found that they helped stay focussed and not become distracted from the lecture.It is notable that the improvements described above do not involve assistance with hearing or language issues, but the extent to which captions improve a more general learning experience. This participant identified themselves as a native English speaker with no disabilities, yet the captions still made a “big difference” in their ability to follow, understand, focus on, and retain information drawn from the lectures.However, while over 60 per cent of students who used the captions reported they found them useful, it was difficult to get more detailed feedback on precisely how and why. Only 52.6 per cent reported actually using them when accessing the lectures, and a relatively small number reported taking advantage of the search and transcripts features available through the Echo360 system. Exactly how they were being used and what role they play in student learning is therefore an area to pursue in future research, as it will assist in breaking down the benefits of captions for all learners.Teaching staff also reported the difficulty in assessing the full value of captions—one teacher interviewed explained that the impact of captions was hard to monitor quantitatively during regular teaching:it is difficult enough to track who listens to lectures at all, let alone who might be using the captions, or have found these helpful. I would like to think that not only those with hearing impairments, but also ESL students and even people who find listening to and taking in the recording difficult for other reasons, might have benefitted.Some teaching staff, however, did note positive feedback from students:one student has given me positive feedback via comments on the [discussion board].one has reported that it helps with retention and with times when speech is soft or garbled. I suspect it helps mediate my accent and pitch!While 60 per cent claiming captions were useful is a solid majority, it is notable that some participants skipped this question. As discussed above, survey answers indicate that this was because these 37 students did not think they had access to captions in their units.Future SignificanceOverall, these results indicate that while captions can provide a benefit to students’ engagement with online lecture learning material, there is a need for more direct and ongoing information sharing to ensure both students and teaching staff are fully aware of captions and how to use them. Technical issues—such as the time delay in captions being uploaded—potentially dissuade students from using this facility, so improving the speed and reliability of this tool could increase the number of learners keen to use it. All staff interviewed agreed that implementing captions for all lectures would be beneficial for everyone:any technology that can assist in making lectures more accessible is useful, particularly in OUA [online] courses.it would be a good example of Universal Design as it would make the lecture content more accessible for students with disabilities as well as students with other equity needs.YES—it benefits all students. I personally find that I understand and my attention is held more by captioned content.it certainly makes my role easier as it allows effective access to recorded lectures. Captioning allows full access as every word is accessible as opposed to note taking which is not verbatim.DiscussionThe results of this research indicate that captions—and their additional features—available through the Echo360 captions system are an aid to student learning. However, there are significant challenges to be addressed to make students aware of these features and their potential benefits.This study has shown that in a cohort of primarily English speaking students without disabilities, over 60 per cent found captions a useful addition to recorded lectures. This suggests that the implementation of captions for all recorded lectures would have widespread benefits for all learners, not only those with hearing or language difficulties. However, at present, only “eligible” students who approach the disability office would be considered for this service, usually students who are D/deaf or hard of hearing. Yet it can be argued that these benefits—and challenges—could also extend to other groups that are might traditionally have been seen to benefit from the use of captions such as students with other disabilities or those from a NESB.However, again, a lack of awareness of the training module meant that this potential cohort did not benefit from this trial. In this study, none of the students who identified as having a disability or coming from a NESB indicated that they had access to the training module. Further, five of the six students with disabilities reported that they did not have access to the captions system and, similarly, only two of the five NESB students. Despite these low numbers, all the students who were part of these two groups and who did access the captions system did find it useful.It can therefore be seen that the main challenge for teaching staff is to ensure all students are aware of captions and can access them easily. One option for reducing the need for training or further instructions might be having captions always ON by default. This means students could incorporate them into their study experience without having to take direct action or, equally, could simply choose to switch them off.There are also a few potential teething issues with implementing captions universally that need to be noted, as staff expressed some concerns regarding how this might alter the teaching and learning experience. For example:because the captioning is once-off, it means I can’t re-record the lectures where there was a failure in technology as the new versions would not be captioned.a bit cautious about the transcript as there may be problems with students copying that content and also with not viewing the lectures thinking the transcripts are sufficient.Despite these concerns, the survey results and interviews support the previous findings showing that lecture captions have the potential to benefit all learners, enhancing each student’s existing capabilities. As one staff member put it:in the main I just feel [captions are] important for accessibility and equity in general. Why should people have to request captions? Recorded lecture content should be available to all students, in whatever way they find it most easy (or possible) to engage.Follow-up from students at the end of the study further supported this. As one student noted in an email at the start of 2017:hi all, in one of my units last semester we were lucky enough to have captions on the recorded lectures. They were immensely helpful for a number of reasons. I really hope they might become available to us in this unit.ConclusionsWhen this project set out to investigate the ways diverse groups of students could utilise captioned lectures if they were offered it as a mainstream learning tool rather than a feature only disabled students could request, existing research suggested that many accommodations designed to assist students with disabilities actually benefit the entire cohort. The results of the survey confirmed this was also the case for captioning.However, currently, lecture captions are typically utilised in Australian higher education settings—including Curtin—only as an assistive technology for students with disabilities, particularly students who are D/deaf or hard of hearing. In these circumstances, the student must undertake a lengthy process months in advance to ensure timely access to essential captioned material. Mainstreaming the provision of captions and transcripts for online lectures would greatly increase the accessibility of online learning—removing these barriers allows education providers to harness the broad potential of captioning technology. Indeed, ensuring that captions were available “by default” would benefit the educational outcomes and self-determination of the wide range of students who could benefit from this technology.Lecture captioning and transcription is increasingly cost-effective, given technological developments in speech-to-text or automatic speech recognition software, and the increasing re-use of content across different iterations of a unit in online higher education courses. At the same time, international trends in online education—not least the rapidly evolving interpretations of international legislation—provide new incentives for educational providers to begin addressing accessibility shortcomings by incorporating captions and transcripts into the basic materials of a course.Finally, an understanding of the diverse benefits of lecture captions and transcripts needs to be shared widely amongst higher education providers, researchers, teaching staff, and students to ensure the potential of this technology is accessed and used effectively. Understanding who can benefit from captions, and how they benefit, is a necessary step in encouraging greater use of such technology, and thereby enhancing students’ learning opportunities.AcknowledgementsThis research was funded by the Curtin University Teaching Excellence Development Fund. Natalie Latter and Kai-ti Kao provided vital research assistance. 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