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In this paper, we propose a distributed iterative hard thresholding algorithm, namely, DiFIGHT, for a network that uses diffusion as the means of intra-network collaboration. Subsequently, we present a modification of the proposed algorithm, namely, MoDiFIGHT, that has lesser communication complexity than DiFIGHT. We additionally propose four different strategies, namely, RP, RNP, RGPr, and RGNPr that are used to randomly select a subset of nodes for taking part in DiFIGHT/MoDiFIGHT. This gives rise to further reduction in the mean number of communications during the run of the proposed distributed algorithms. We present theoretical estimates of the long run communication per unit time, both for DiFIGHT and MoDiFIGHT, with and without random selection of nodes. Also, we present theoretical analysis of the two proposed algorithms and provide provable bounds on their recovery performance with or without using the random node selection strategies. Finally we use numerical studies to show that both with and without random selections, the proposed algorithms exhibit performances far superior to the consensus based distributed IHT algorithm.

In greedy pursuit algorithm, atom selection is commonly a concerned topic for signal compressed recovery. To improve the recovery performance, an optimal atom selection strategy without the prior information is proposed in this paper. The sensing information entropy is defined to prune the possible false atoms in the estimated support set. Fewer iterations are required in the proposed strategy and it can also be applied in the case with high sparsity level or low signal-noise-ratio. Compared with the existing representative algorithms, the superiority of the recovery error and probability is verified by the simulations. Furthermore, the proposed method is applied to recover the real random modulated signal. The results show that the recovered signal has greater consistence with the original input signal.

An unsymmetrical diphenylphosphino-pyridinyl-triazole ligand was synthesized and characterized through IR, NMR and MS and the corresponding earth-abundant metal complex (cobalt) was prepared. Considering energy consumption and environmental friendliness, it is necessary to turn this diphenylphosphino-pyridinyl-triazole cobalt complex into a recyclable catalyst, which could easily be reused. Therefore, a heterogeneous catalyst was synthesized through Co-doping of C3N4, and the Co-nanoparticles on C3N4 revealed high catalytic activity for the synthesis of quinolines with good recovery performance.

Erasure codes are being extensively deployed in practical storage systems to prevent data loss with low redundancy. However, these codes require excessive disk I/Os and network traffic for recovering unavailable data. Among all erasure codes, Minimum Storage Regenerating (MSR) codes can achieve optimal repair bandwidth under the minimum storage during recovery, but some open issues remain to be addressed before applying them in real systems. Facing with the huge burden during recovery, erasure-coded storage systems need to be developed with high repair efficiency. Aiming at this goal, a new class of coding scheme is introduced—Hybrid Regenerating Codes (Hybrid-RC). The codes utilize the superiority of MSR codes to compute a subset of data blocks while some other parity blocks are used for reliability maintenance. As a result, our design is near-optimal with respect to storage and network traffic and shows great improvements in recovery performance.

As a rural development approach, concentrated rural settlement (CRS) was used for rural reconstruction when Wenchuan earthquake opened the opportunity window of quick and wide implementation. Although CRS has both proponents and critics, few studies have investigated the recovery success of villages reconstructed with CRS. This research gap has resulted in insufficient theoretical guidance for the practice of CRS and inefficient summarization and transfer of relevant experiences. This study therefore aims to measure the recovery success of three villages reconstructed with CRS located in the hardest-hit areas of the Wenchuan earthquake. Full-permutation polygon synthetic indicator method is adopted to evaluate the recovery success of the three case villages from the economic, social, environmental and disaster relief aspects. It is found that the three case villages have good overall recovery performances as economic, social, and environmental aspects improved a lot from 2008 to 2015, whereas the disaster relief recovery performance increased at the first several years but dramatically decreased at the later years. The implications inferred from the case studies are discussed in detail. This study provides a reference to local governments for monitoring CRS development and for improving recovery of villages reconstructed with CRS.

A vast amount of construction and demolition (C&D) wastes are generated in Western Australia (WA) of which a major portion goes to landfills. The diversion of C&D waste from landfills would be the single most significant opportunity for WA to improve its recovery performance. C&D waste materials have already been investigated for their appropriateness and use in pavement and concrete. This work is the continuation of the authors’ previous work involving further experimental tests to prove the structural suitability of a building’s structural member (i.e., beam) made of recycled aggregates and industrial by-products. The concrete mixes considered in this study are 100NA+100 OPC (Control), 100RA+100OPC, 50RA+50NA+90OPC+10SF and 50RA+50NA+60OPC+30FA+10SF. The Reinforced Concrete (RC) beam made of 50RA+50NA+60OPC+30FA+10SF concrete mix was found to be the only eco-efficient option. This option has reduced the level of environmental impacts in a cost-competitive manner. The use of this eco-efficient option could also provide new employment opportunities and significant improvements in terms of land and energy resources conservation and bio-diversity enhancement.

Vertically laid nonwoven fabrics are structurally different from conventional cross-laid nonwoven fabrics, resulting in an exceptional bulkiness and unique compressional recovery performance. In this paper, two testing methods (manual procedure vs. machine procedure) to determine bulky nonwoven thickness were first studied and statistically analyzed. Then, pore sizes of selected nonwoven samples were measured by a porosimeter to examine relationship between the pore size and nonwoven structural parameters. Finally, compressive properties of the nonwoven samples were measured by an Instron tester for assessment of main effects of nonwoven structural parameters in terms of thickness, gram weight, bulk density, and porosity on nonwoven compressional properties. The results showed that there was no significant difference between the two thickness measurement methods, and the manual measurement was basically consistent with the machine measurement. Bubble point pore size and average flow pore size were correlated with the structure parameters in varied correlation coefficients. Compared to cross-laid nonwovens, vertically laid nonwovens exhibited a greater compressive energy and linearity and a lower compressive resilience.

The steam-assisted gravity drainage (SAGD) process is effective to improve oil recovery performance, but it also promotes the aquathermolysis reaction of heavy oil under high-temperature reservoir ...

Micro‐gel particle suspensions (MGPS) have been proposed for enhanced oil recovery (EOR) in reservoirs with harsh conditions in recent years, yet the mechanisms are still not clear because of the complex property of MGPS and the complex geometry of rocks. In this paper, the micro‐gel particle‐based flooding has been studied by our microfluidic experiments on both bi‐permeability micromodels and reservoir‐on‐a‐chip. A method for reservoir‐on‐a‐chip design has been proposed based on QSGS (quartet structure generation set) to ensure that the flow geometry on chip owns the most important statistical features of real rock microstructures. In the micromodel experiments with heterogeneous microstructures, even if the MGPS has the same macroscopic rheology as the hydrolyzed polyacrylamides (HPAM) solution for flooding, MGPS may lead to significant fluctuations of pressure field caused by the nonuniform concentration distribution of particles. In the reservoir‐on‐a‐chip experiments, clustered oil trapped in the swept pores can be recovered by MGPS because of pressure fluctuation, which hardly happens in the HPAM flooding. Compared with the water flooding, the HPAM solution flooding leads to approximately 17% incremental oil recovery, while the MGPS results in approximately 49.8% incremental oil recovery in the laboratory.

This study investigates the impact of design parameters on oil recovery performance in polymer flooding (PF) with low-salinity water-flooding (LSWF). Convergence technology for enhanced oil recover...

Several drift-diffusion models have been developed to account for the performance in conflict tasks. Although a common characteristic of these models is that the drift rate changes within a trial, their architecture is rather different. Comparative studies usually examine which model fits the data best. However, a good fit does not guarantee good parameter recovery, which is a necessary condition for a valid interpretation of any fit. A recent simulation study revealed that recovery performance varies largely between models and individual parameters. Moreover, recovery was generally not very impressive. Therefore, the aim of the present study was to introduce and test an improved fit procedure. It is based on a grid search for determining the initial parameter values and on a specific criterion for assessing the goodness of fit. Simulations show that not only the fit performance but also parameter recovery improved substantially by applying this procedure, compared to the standard one. The improvement was largest for the most complex model.

Blockage in reservoirs caused by asphaltene deposits and inorganic interactions is a serious problem that may exacerbate the complexity of displacement characteristics in heterogeneous multilayer s...

The success of supercritical CO2 Enhanced Oil Recovery (EOR) cannot be duplicated if the cost of CO2 transposition and processing becomes prohibitive. Research results of the in-situ CO2 EOR (ICE) approach offered a potential technology for many waterflooded stripper wells that lack access to affordable CO2 sources. Previously the ICE synergetic mechanisms were only qualitatively attributed to oil swelling and viscosity reduction due to the preferential partition of CO2 into the oleic phase. This study aims to quantify the contributions to recovery factors from several plausible mechanisms with numerical modeling and simulation. First, the urea reaction was modeled as the CO2 generating chemical decomposing to CO2 and ammonia in the reservoir conditions. The CO2 partitions into oil, which leads to the reaction continuation to generate more CO2. The resulting ammonia largely left in water may further react with certain crudes to generate surfactants, thus, decrease the oil/water interfacial tension (IFT). It is expected that the oil containing CO2 also has a lower IFT with water. The reaction kinetics under different temperatures were incorporated into the numerical model. A numerical model featuring the synergetic mechanisms was built including stoichiometry and kinetics of urea reaction, oil swelling effect, oil viscosity reduction, and IFT reduction effect on the relative permeabilities. The laboratory experiments, pore volume injection versus oil saturation were history matched for three different oils including Dodecane, Earlsboro oil, and DeepStar oil. The phase behavior was modeled with the equation of state (EOS) under different mole fractions of CO2. The reaction kinetics were also modified to history match the laboratory experiment. The estimated reduction of oil viscosity was calculated, 76% for Earlsboro oil, 91% in DeepStar oil, and 75% in dodecane oil. The oil swelling factors ranged from 1.60% to 19% in the three lab models, which translates to the recovery factor of oil. The endpoints of relative permeability were modified to account for the recovery contribution to the IFT and viscosity reduction. The impact of reaction kinetics on oil swelling and recovery factor was also determined, and they are not numerically close to reaction kinetics used in the lab cases. The matched reaction kinetics, activation energy and reaction frequency factor for the dodecane laboratory experiment were 91.80 kJ/gmol and 6.5E+09 min−1. The study concluded that the incremental recovery due to oil swelling ranges between 3.16% and 18.30%, and then from 12.91% to 41.59% is due to IFT reduction for all the cases. The relative permeability and urea reaction kinetics remained the most uncertain parameters during history matching and modeling the ICE synergetic mechanisms.

In this study, the effects of different storage conditions, such as temperature, storage time and biomass form, on the properties of anaerobic ammonia oxidation (anammox) were investigated along with the identification of the process mechanism. The results showed that the influence of storage time on anammox properties was stronger than that of storage temperature and biomass form. Also, the anammox recovery activity at 15 °C was better than that at 4 °C, and the anammox recovery activity of immobilized filler was better than that of anammox granular sludge (AnGS). Although cryogenic storage severely damaged anammox activity, lower loss of extracellular polymeric substances maintained the AnGS structure. The maximum recovery of specific anammox activity at 15 °C for the immobilized filler was observed to be 109%. In addition, intermittent substrate supplementation weakened the adverse effect of long-term storage on anammox activity, and was conducive to maintaining stable flora composition and promoting regeneration of anammox bacteria (AnAOB). High-throughput sequencing analysis showed that starvation resulted in increased community diversity, and the functional bacteria Candidatus Brocadia was observed to be more tolerant to starvation than Candidatus Kuenenia. Finally, principal component analysis was used to explain the complex relationship between process performance and preservation conditions. Based on the results of this work, it is recommended to preserve AnAOB in the form of immobilized filler at 15 °C and supplement substrate intermittently during long term storage. This study provides an economical and robust strategy for the short-term and long-term preservation of AnAOB.

The amounts of the components in a microcapsule self-healing system significantly impact the basic performance and self-healing performance of concrete. In this paper, an orthogonal experimental design is used to investigate the healing performance of microcapsule self-healing concrete under different pre-damage loads. The strength recovery performance and sound speed recovery performance under extensive damage are analyzed. The optimum factor combination of the microcapsule self-healing concrete is obtained. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) are carried out on the concrete samples before and after healing to determine the healing mechanism. The results show that the healing effect of self-healing concrete decreases with an increase in the pre-damage load, and the sound speed recovery rate increases with an increase in the damage degree. The influence of the sodium silicate content on the compressive strength and compressive strength recovery rate of the self-healing concrete increases, followed by a decrease. The optimum combination of factors of the microcapsule self-healing system is 3% microcapsules, 30% sodium silicate, and 15% sodium fluosilicate. The results can be used for the design and preparation of self-healing concrete.

Over the past two decades, a number of control strategies have been developed for powered transfemoral prostheses. These strategies have in common that they help restore gait in amputee locomotion. However, it remains unclear how well they support balance recovery after disturbances. Here, we first present a comparison of balance recovery performance among current controls for powered transfemoral when their users are subjected to unexpected ground slips. While some controls perform better than others in this comparison, they all suffer from a limited awareness of both the environment and the user’s intent, which inevitably leads to catastrophic failures and eventual falls. We then introduce our current efforts toward more interactive prosthesis controls that continuously adapt to changes in the environment and user intent. In initial work, we find that such continuous adaptations substantially improve gait robustness, encouraging a more aggressive research agenda toward real-time reactive leg prosthesis controls.

Isophorone diisocyanate (IPDI) was encapsulated successfully within double-layered shells, and final microcapsules showed outstanding self-healing functions in cement paste. The well-disper...

Disertación de tesis de maestría en Ciencias -Meteorología en formato PDF. ilustraciones, mapas El agua es uno de los componentes más importantes de nuestro planeta, está presente en la naturaleza en tres estados, así como en la atmósfera, superficie de la tierra y océanos. La humedad del suelo es una de las variables agroclimáticas esenciales debido a su importancia en los flujos de agua y energía entre la tierra y la atmósfera. En las últimas décadas su estimación a escala regional ha cobrado relevancia para resolver problemas hidrológicos, meteorológicos y agronómicos; en este sentido las redes de sensores in situ sobre el territorio colombiano no son suficientes para caracterizar adecuadamente la condición de humedad de las zonas agrícolas. En este contexto, el objetivo de la tesis fue evaluar métodos de estimación oportuna de las condiciones de humedad superficial para el territorio colombiano, determinando por regiones cuál o cuáles serían las fuentes más promisorias para la implementación de aplicaciones en diversas disciplinas, que contribuyan en la toma de decisiones tanto para agricultores, líderes nacionales, regionales y locales, así como para técnicos del sector, investigadores y pronosticadores, entre otros. Para ello, se aplicó la metodología de control de calidad desarrollada para la Red Internacional de Humedad de Suelo (ISMN, por sus siglas en inglés) ajustada a las condiciones ecuatoriales de Colombia. Con las mediciones de humedad de suelo consideradas buenas se realizó el análisis espacio-temporal de la variable con el fin de determinar cuál es la relación entre la humedad de suelo, con las variables atmosféricas, características físicas, topográficas y de cobertura vegetal. Con el fin de evaluar las estimaciones de humedad superficial, se realizó la revisión bibliográfica de fuentes de estimación remota por microondas y/o modelos de superficie, sus características, ventajas y desventajas, metodologías de validación, que pudieran ser aplicadas de manera efectiva para las condiciones particulares del territorio colombiano. Basándose en la revisión de fuentes de estimación, se realizó la selección de fuentes de estimación de humedad concentrándose en las bandas de recuperación que tuvieran mayor potencial (L y C), adicionando también productos de estimación en la banda X, productos de combinación de radares activos-pasivos y productos de reanálisis con el fin de realizar una revisión lo más completa posible de la diversidad de fuentes de estimación. Posteriormente se realizó la validación de ocho (8) fuentes de estimación (5 de satélite de misión única, 1 de combinación de misiones satelitales radares activos-pasivos y 2 fuentes de reanálisis) desglosados en 23 productos de estimación de humedad superficial. Entre los principales resultados, se encontró que las estimaciones de combinaciones de diversidad de bandas, pasos de órbitas y misiones presentan los mejores rendimientos, regiones con condiciones de baja cobertura vegetal, pendientes suaves y clasificaciones climáticas cálidas presentan las mejores métricas de validación. Sin embargo, para regiones con topografía montañosa, vegetación densa y climas fríos los modelos de superficie son una fuente de estimación promisoria, que con las parametrizaciones adecuadas se pueden mejorar significativamente las estimaciones de la humedad superficial. (Texto tomado de la fuente) Water is one of the most important components of our planet, it is present in nature in three states, as well as in the atmosphere, the earth's surface and the oceans. Soil moisture is one of the essential agroclimatic variables due to its importance in the flow of water and energy between the earth and the atmosphere. In recent decades, its estimation on a regional scale has gained relevance in solving hydrological, meteorological and agronomic problems; In this sense, in situ sensor networks on Colombian territory are not sufficient to adequately characterize the humidity condition of agricultural areas. In this context, the objective of the thesis was to evaluate methods for the timely estimation of surface humidity conditions for the Colombian territory, determining by regions which or which would be the most promising sources for the implementation of applications in various disciplines, which contribute to the decision-making for farmers, national, regional and local leaders, as well as for sector technicians, researchers and forecasters, among others. For this, the quality control methodology developed for the International Soil Moisture Network (ISMN) was applied, adjusted to the equatorial conditions of Colombia. With the soil moisture measurements considered good, the spatio-temporal analysis of the variable was carried out to determine what is the relationship between the soil moisture, with the atmospheric variables, physical, topographic and plant cover characteristics. To evaluate the surface moisture estimates, a bibliographic review of remote estimation sources by microwaves and / or surface models, their characteristics, advantages and disadvantages, validation methodologies, that could be applied effectively for the particular conditions of the Colombian territory. Based on the review of estimation sources, the selection of humidity estimation sources was made, concentrating on the recovery bands that had the greatest potential (L and C), also adding estimation products in the X band, radar combination products active-passive radar and products of a reanalysis to carry out a review as complete as possible of the diversity of sources of estimation. Subsequently, the validation of eight (8) estimation sources was carried out (5 from single mission satellites, 1 from a combination of active-passive radar satellite missions and 2 reanalysis sources) broken down into 23 surface moisture estimation products. Among the main results, it was found that the estimates of combinations of band diversity, orbital passages and missions present the best performance, regions with conditions of low vegetation cover, gentle slopes and warm climatic classifications present the best validation metrics. However, for regions with mountainous topography, dense vegetation and cold climates, surface models are a promising source of estimation, which with the appropriate parameterization can significantly improve the estimates of surface moisture. (Texto tomado de la fuente) FEDEARROZ - FEDERACION NACIONAL DE ARROCEROS, con la administración del Fondo Nacional del Arroz, parafiscal recaudado por la venta de arroz paddy verde en Colombia que corresponde al 0.5% del valor comercial del paddy al momento de la comercialización. Financia la investigación para el cultivo de arroz en Colombia y la adopción de capacidades de los investigadores adscritos al Fondo Nacional del Arroz, en la ampliación de las capacidades de los investigadores mediante la realización de estudios de maestría. Maestría Magíster en Ciencias - Meteorología Meteorología Agrícola y Meteorología Aplicada

We present the design, implementation, and evaluation of INSTalytics , a co-designed stack of a cluster file system and the compute layer, for efficient big-data analytics in large-scale data centers. INSTalytics amplifies the well-known benefits of data partitioning in analytics systems; instead of traditional partitioning on one dimension, INSTalytics enables data to be simultaneously partitioned on four different dimensions at the same storage cost, enabling a larger fraction of queries to benefit from partition filtering and joins without network shuffle. To achieve this, INSTalytics uses compute-awareness to customize the three-way replication that the cluster file system employs for availability. A new heterogeneous replication layout enables INSTalytics to preserve the same recovery cost and availability as traditional replication. INSTalytics also uses compute-awareness to expose a new sliced-read API that improves performance of joins by enabling multiple compute nodes to read slices of a data block efficiently via co-ordinated request scheduling and selective caching at the storage nodes. We have built a prototype implementation of INSTalytics in a production analytics stack, and we show that recovery performance and availability is similar to physical replication, while providing significant improvements in query performance, suggesting a new approach to designing cloud-scale big-data analytics systems.