A Study of Reactive Transport Phenomena in Porous Media

This work was also published as a Rice University thesis/dissertation: http://hdl.handle.net/1911/19202The numerical modeling of reactive transport in a porous medium has important applications in hydrology, the earth sciences and in numerous industrial processes. However, realistic simulations involving a large number of chemical species undergoing simultaneous transport and chemical transformation present a significant computational challenge, particularly in multiple spatial dimensions. A framework for analyzing the chemical batch problem is first introduced, which is sufficiently general to allow for reaction of both equilibrium and kinetic type. The governing equations for reactive transport of a single flowing phase through a porous medium are presented next, and a classification based on the nature of the reactive system is established. A computer module for the equilibrium problem is developed, based on a novel application of the interior-point algorithm for nonlinear programming. Among its advantages are good global convergence and automatic selection of mineral phases. To handle kinetic reactions, the equilibrium module is embedded in a time-integration framework using explicit ODE integrators. Reactive transport of species is achieved through operator-splitting, which enables a straightforward incorporation of the batch module into the existing parallel, three-dimensional, single-phase flow and transport simulator PARSim1. Numerical results are presented which demonstrate the correctness of the computer program for major classes of geochemistry problems, including ion-exchange, precipitation/dissolution, adsorption, aqueous complexation and redox reactions

Penerapan Model Pembelajaran Kooperatif Tipe Teams Games Tournament (TGT) Menggunakan Permainan Ular Tangga untuk Meningkatkan Hasil Belajar Siswa Kelas X I pada Materi Koloid di SMAN I Baitussalam Aceh Besar

Telah dilakukan penelitian dengan judul “Penerapan Model Pembelajaran Kooperatif Tipe Teams Games Tournament (TGT) Menggunakan Permainan Ular Tangga untuk Meningkatkan Hasil Belajar Siswa Kelas XI pada Materi Koloid Di SMAN I Baitussalam Aceh Besar”. Adapun tujuan penelitian adalah untuk mengetahui perbedaan keaktifan siswa terhadap penerapan model pembelajaran kooperatif tipe Teams Games Tournament dengan permainan ular tangga pada materi koloid dibandingkan dengan metode konvensional dan untuk mengetahui perbedaan hasil belajar siswa kelas XI melalui penerapan model pembelajaran kooperatif tipe Teams Games Tournament dengan permainan ular tangga pada materi koloid dibandingkan dengan metode konvesional. Penelitian ini adalah penelitian eksperimen dengan menggunakan kelas eksperimen dan kelas kontrol. Data dikumpulkan melalui tes hasil penelitian menunjukkan bahwa terdapat 84,72 % siswa yang aktif dalam pembelajaran, sedangkan hasil belajar siswa menunjukkan nilai rata-rata pretest kelas eksperimen 41,6 dan nilai rata-rata pretestkelas kontrol 39 sedangkan nilai rata-rata posttest kelas eksperimen 78,9 dan nilai rata-rata postestkelas kontrol 58,5. Berdasarkan hasil pengolahan data diperoleh thitung = 19,263 dan ttabel dengan taraf signifikan α = 0,05 dan dk = 38, dengan cara interpolasi diperoleh t0,95(38) = 1,68 sehingga diperoleh thit> ttab, hasil ini jelas adadalam daerah penolakan Ho dan berada dalam penerimaan Ha. Dari analisis data dapat disimpulkan bahwa hasil belajar siswa yang diajarkan menggunakan penerapan model pembelajaran kooperatif tipe Teams Games Tournament (TGT) Menggunakan Permainan Ular Tangga lebih baik daripada hasil belajar yang diajarkan menggunakan metode pembelajaran konvensional

Accompagner les acteurs dans le changement de leur système Un jeu de rôles pour des projets collectifs d'irrigation au Tadla, Maroc

Les petites exploitations agricoles du périmètre irrigué du Tadla font actuellement face à de profonds changements environnementaux, institutionnels et économiques. Les ressources hydriques diminuent, l'Etat marocain se repositionne vis-à-vis de la gestion des grands périmètres irrigués et les marchés s'ouvrent (libre-échange). L'organisation des petites exploitations autour de projets collectifs d'irrigation (PCI) visant la reconversion à l'irrigation localisée représente une solution prometteuse pour faire face à cette nouvelle situation. Ces PCI nécessitent un profond changement du système traditionnel des agriculteurs, tant sur le plan technique qu'organisationnel. Ce changement est mis en oeuvre à travers une action collective innovante dont l'accompagnement requiert de nouvelles formes d'intervention. S'inscrivant dans un processus participatif plus général visant à soutenir la mise en oeuvre des PCI au Tadla, un jeu de rôles a ainsi été développé. A travers cet exercice, des groupes pilotes d'agriculteurs et de gestionnaires ont pu expérimenter, d'une manière virtuelle, les différentes étapes de la mise en oeuvre d'un PCI. Ce jeu de rôles a été utilisé pour développer, en anticipation, un savoir commun sur les PCI, ce qui a permis de renforcer l'implication et le pouvoir de décision des agriculteurs vis-à-vis du projet collectif, tout en facilitant les étapes ultérieures du processus. On a pu ainsi formaliser les attentes de ces derniers et révéler les questions problématiques. Par ailleurs, ce jeu de rôles s'est avéré être un outil efficace pour révéler les projets individuels des agriculteurs. Cet outil participatif ouvre une voie prometteuse dans le développement de nouvelles formes d'intervention destinées à accompagner des acteurs dans l'évolution de leur système. Au Tadla, le transfert de cette approche à des organisations professionnelles locales pourrait permettre le développement des PCI, et leur accompagnement à plus large échelle, spatiale et temporelle

Computational methods for multiphase flow and reactive transport problems arising in subsurface contaminant remediation

AbstractA mathematical formulation and some numerical approximation techniques are described for a system of coupled partial differential and algebraic equations describing multiphase flow, transport and interactions of chemical species in the subsurface. A parallel simulator PARSIM has been developed based on these approximation techniques and is being used to study contaminant remediation strategies. Numerical results for a highly complex geochemistry problem involving strontium disposal in a pit at Oak Ridge National Laboratory are presented

ANALISIS KENYAMANAN TERMAL RUANGAN KELAS DENGAN MENGGUNAKAN METODE ANALYTICAL HIERARCHY PROCESS (AHP) (STUDI KASUS : SEKOLAH MENENGAH PERTAMA (SMP) DI KOTA BANDA ACEH)

Analisis Kenyamanan Termal Ruangan Kelas Dengan Menggunakan Metode Analytical Hierarchy Process (AHP) (Studi Kasus : Sekolah Menengah Pertama (SMP) di Kota Banda Aceh)ABSTRAKKenyamanan termal merupakan suatu perasaan dimana seseorang merasa nyaman dengan lingkungan sekitar yang dapat digambarkan menjadi suatu kondisi seseorang tidak merasakan kepanasan maupun kedinginan pada lingkungannya. Kenyamanan termal suatu ruangan dapat diketahui melalui perhitungan skala Predicted Mean Vote (PMV) dan Predicted Percentage Dissatisfied (PPD) yang mempunyai nilai indeks yaitu dari -3 (sangat dingin) sampai dengan +3 (sangat panas). Penelitian ini menentukan dan mengidenfikasi faktor yang mempengaruhi kenyamanan termal ruangan kelas, serta mengamati dan mengukur faktor tersebut, serta menyusun kriteria dan subkriteria sehingga diperoleh alternatif terpilih untuk meningkatkan kenyamanan termal ruangan kelas. Faktor yang sangat mempengaruhi kenyamanan termal ruangan kelas adalah secara personal yaitu rate metabolisme dan insulan pakaian, sedangkan secara iklim ruangan adalah suhu udara, suhu radian, kelembaban, dan kecepatan angin. Penelitian dilakukan pada 5 SMP di Kota Banda Aceh untuk menganalisis dan mencari solusi meningkatkan kenyamanan termal ruangan kelasnya. Menganalisis kenyamanan termal dilakukan dengan menggunakan metode skala Predicted Mean Vote (PMV) dan Predicted Percentage Dissatisfied (PPD), sedangkan untuk mencari solusi yang menentukan suatu pengambilan keputusan meningkatkan kenyamnanan termal ruangan kelas adalah menggunakan metode analytical hierarchy process (AHP). Data yang di peroleh bedasarkan penelitian ini adalah data kuantitatif yaitu data yang dalam bentuk angka. Hasil yang diperoleh dalam penelitian ini adalah indeks kenyamanan termal ruangan yang didapatkan adalah rata-rata mencapai +2 (panas), dan bahkan memperoleh nilai PPD sebesar 91%. Pengambilan keputusan atau alternatif terpilih bedasarkan penyusunan kriteria dan subkriteria maka alternatif yang terpilih sebagai solusi peningkatan kenyamanan termal ruangan kelas adalah vegetasi alami.Kata kunci : Kenyamanan Termal, Predicted Mean Vote (PMV), Predicted Percentage Dissatisfied (PPD), Indeks, Analytical Hierarchy Process (AHP).Thermal Comfortness of Classrooms Analysis Using the Analytical Hierarchy Process (AHP) Method (Case Study: Junior High Schools in Banda Aceh City)ABSTRACTThermal comfortness is a sense where someone feels comfortable with the environment around which can be described into a condition of someone did not feel overheated and chilled on the environment. Thermal comfortness of a room can be known through calculation scale Predicted Mean Vote (PMV) and Predicted Percentage Dissatisfied (PPD), which has index value from -3 (very cold) to +3 (very hot). This research determines and identifies factors affecting the thermal comfortness of classrooms, also observe and measure these factors, as well as the criteria and sub-criteria in order to obtain the selected alternative to improve the thermal comfortness of the classroom. Factors that intensely affect the thermal comfortness of classrooms are personally rate metabolism and insulan clothing, while the climate in the room are air temperature, radiant temperature, humidity, and wind speed. The study was conducted to five Junior High Schools in Banda Aceh to analyze and find solutions to improve the thermal comfortness of classrooms. Analyzing thermal comfortness were calculated using a scale Predicted Mean Vote (PMV) and Predicted Percentage Dissatisfied (PPD), meanwhile to find solutions that determine a decision making to improve the thermal comfortness of classrooms using the analytical hierarchy process (AHP) method. The data obtained according to this research is quantitative data that is data in the form of numbers. The results obtained from this research is thermal comfortness of classrooms index reached is an average of + 2 ( heat ) , and even get PPD value of 91 % . Decision making or selected alternative based on the preparation of criteria and sub-criteria, so the selected alternative as a solution to improve the thermal comfort of classrooms is natural vegetation.Keywords : Thermal Comfortnes, Predicted Mean Vote (PMV), Predicted Percentage Dissatisfied (PPD), Index, Analytical Hierarchy Process (AHP)

Country profile Egypt

This country profile, commissioned by The Netherlands Ministry of Foreign Affairs (Department of Inclusive Green Growth), gives a snapshot of what is happening in the closely interrelated themes Food & Nutrition Security, Water, Climate (including Renewable Energy) in Egypt. It provides basic statistics on Egypt’s performance on key indicators and indexes, but also analyses relevant national policies, current donor interventions, and the main trends on the abovementioned themes. Combined with an overview of Dutch support to Egypt, this profile concludes by suggesting potential priority result areas for The Netherlands

Hydrophobically stabilized open state for the lateral gate of the Sec translocon

The Sec translocon is a central component of cellular pathways for protein translocation and membrane integration. Using both atomistic and coarse-grained molecular simulations, we investigate the conformational landscape of the translocon and explore the role of peptide substrates in the regulation of the translocation and integration pathways. Inclusion of a hydrophobic peptide substrate in the translocon stabilizes the opening of the lateral gate for membrane integration, whereas a hydrophilic peptide substrate favors the closed lateral gate conformation. The relative orientation of the plug moiety and a peptide substrate within the translocon channel is similarly dependent on whether the substrate is hydrophobic or hydrophilic in character, and the energetics of the translocon lateral gate opening in the presence of a peptide substrate is governed by the energetics of the peptide interface with the membrane. Implications of these results for the regulation of Sec-mediated pathways for protein translocation vs. membrane integration are discussed

Membrane insertion and topology of the TRanslocating chain-Associating Membrane protein (TRAM)

The translocating chain-associating membrane protein (TRAM) is a glycoprotein involved in the translocation of secreted proteins into the endoplasmic reticulum (ER) lumen and in the insertion of integral membrane proteins into the lipid bilayer. As a major step toward elucidating the structure of the functional ER translocation/insertion machinery, we have characterized the membrane integration mechanism and the transmembrane topology of TRAM using two approaches: photocross-linking and truncated C-terminal reporter tag fusions. Our data indicate that TRAM is recognized by the signal recognition particle and translocon components, and suggest a membrane topology with eight transmembrane segments, including several poorly hydrophobic segments. Furthermore, we studied the membrane insertion capacity of these poorly hydrophobic segments into the ER membrane by themselves. Finally, we confirmed the main features of the proposed membrane topology in mammalian cells expressing full-length TRAM

Protein docking by Rotation-Based Uniform Sampling (RotBUS) with fast computing of intermolecular contact distance and residue desolvation

<p>Abstract</p> <p>Background</p> <p>Protein-protein interactions are fundamental for the majority of cellular processes and their study is of enormous biotechnological and therapeutic interest. In recent years, a variety of computational approaches to the protein-protein docking problem have been reported, with encouraging results. Most of the currently available protein-protein docking algorithms are composed of two clearly defined parts: the sampling of the rotational and translational space of the interacting molecules, and the scoring and clustering of the resulting orientations. Although this kind of strategy has shown some of the most successful results in the CAPRI blind test <url>http://www.ebi.ac.uk/msd-srv/capri</url>, more efforts need to be applied. Thus, the sampling protocol should generate a pool of conformations that include a sufficient number of near-native ones, while the scoring function should discriminate between near-native and non-near-native proposed conformations. On the other hand, protocols to efficiently include full flexibility on the protein structures are increasingly needed.</p> <p>Results</p> <p>In these work we present new computational tools for protein-protein docking. We describe here the RotBUS (Rotation-Based Uniform Sampling) method to generate uniformly distributed sets of rigid-body docking poses, with a new fast calculation of the optimal contacting distance between molecules. We have tested the method on a standard benchmark of unbound structures and we can find near-native solutions in 100% of the cases. After applying a new fast filtering scheme based on residue-based desolvation, in combination with FTDock plus pyDock scoring, near-native solutions are found with rank ≤ 50 in 39% of the cases. Knowledge-based experimental restraints can be easily included to reduce computational times during sampling and improve success rates, and the method can be extended in the future to include flexibility of the side-chains.</p> <p>Conclusions</p> <p>This new sampling algorithm has the advantage of its high speed achieved by fast computing of the intermolecular distance based on a coarse representation of the interacting surfaces. In addition, a fast desolvation scoring permits the screening of millions of conformations at low computational cost, without compromising accuracy. The protocol presented here can be used as a framework to include restraints, flexibility and ensemble docking approaches.</p