Viscous fingering and its effect on areal sweep efficiency during waterflooding: an experimental study

Viscous fingering is one of the main challenges that could reduce areal sweep efficiency during waterflooding in oil reservoirs. A series of waterflooding experiments were carried out in a Hele-Shaw cell at ambient temperature during which areal sweep efficiency was estimated and techniques to ease the fingering problem were examined. The onset and propagation of viscous fingers were monitored as a function of both injection rate and injection/production positions. Image processing techniques were utilized to quantitatively investigate the propagation of fingers. The experimental results show that, under specific conditions, increasing the number of finger branches could improve the areal sweep efficiency, whereas growth of a single narrow finger has a negative impact on oil displacement efficiency. According to the obtained results, increasing the injection rate improves the areal sweep efficiency up to a critical rate at which viscous fingers start to grow. The impact of heterogeneity of the medium on distributing the viscous fingers was also investigated by introducing two different arrangements of fractures in the model. The results show that fractures perpendicular to the direction of flow would distribute the displacing water more uniformly, while fractures in the direction of flow would amplify the unfavorable sweep efficiency.     

Dynamic Resource Allocation for Multimedia Document Retrieval over High Speed LANs

The emergence of gigabit local area networks (G-LANs) has spurred a tremendous interest in supporting networked multimedia applications over a LAN. In this paper, we propose a mechanism for dynamically allocating network resources in asynchronous LANs. Presentation of multimedia objects with required play-out quality requires Quality of Service (QoS) guarantees by the underlying networking infrastructure. Existing asynchronous LANs, such as Ethernet, do not support the notion of QoS due to their asynchronous media access protocol. For such networks, we propose a dynamic bandwidth management scheme that uses the concept of Time Division Multiple Access (TDMA). Significant performance improvement is observed through experimental results. In particular, the transmission rates for multimedia hosts improve significantly with low jitter variations in media streams. We also propose a framework for graceful degradation of play-out quality of multimedia objects in case the LAN's total capacity is not sufficient to meet the overall demand.     

Monitoring and Evaluation Scheme using the Multiple-Criteria-Decision-Making Technique: Application to Irrigation Projects

The application of monitoring and evaluation (M&E) systems to assess agricultural projects has received some attention in recent years. These systems provide valuable information for managers and decision makers by analyzing the implementation process, the progress of trends, and the long-term and short-term effectiveness of these projects. An algorithm is developed to monitor and evaluate drip and pressure irrigation projects in Iran. Different indicators are identified and the framework of an integrated evaluation system is demonstrated using an analytical hierarchy process for multiple-criteria-decision making. There is much subjective information that is quantified and normalized in order to remove any bias in evaluators’ assessment of qualitative measures or sensitivity to linguistic expressions. The application of this system to rank projects in different regions (zones) in Iran is also presented in this paper. The results have shown the significant value of such systems in providing information and input for different decision-making levels.     

Soil Moisture Information And Thermal Microwave Emission

This paper presents theoretical and experimental results that demonstrate the depth to which soil moisture can be directly measured using microwave radiometers. The experimental results also document the effect of uniform surface roughness on the response of thermal microwave emission to soil moisture. Experimental measurements were executed in July 1980 at the Texas A&M University Research Farm near College Station, TX. Thermal microwave emission measurements were made at 1.4, 4.9, and 10.7 GHz at both vertical and horizontal polarization at off nadir angles from 0 to 50°. It has been demonstrated that passive microwave measurements at frequencies down to 1.4 GHz can only measure soil moisture directly to very shallow soil depths, approximately 2 cm. This is due to the fact that the soil moisture dependence of the transmission coefficient across the air-soil interface predominates over the soil moisture dependence of the total energy originating within the soil volume. It also has been demonstrated that the combination of low incident angle and measurement frequency in the C-band range does not minimize the effect of surface roughness for passive microwave measurements. This result is significant in view of the fact that this combination of frequency and incident angle has been described as the optimum combination for minimizing the effect of surface roughness on the response of radar-backscatter measurements to soil moisture.     

Monoclonal behavior of molecularly imprinted polymer nanoparticles in capillary electrochromatography

A new approach based on miniemulsion polymerization is demonstrated for synthesis of molecularly imprinted nanoparticles (MIP-NP; 30-150 nm) with "monoclonal" binding behavior. The performance of the MIP nanoparticles is characterized with partial filling capillary electrochromatography, for the analysis of rac-propranolol, where (S)-propranolol is used as a template. In contrast to previous HPLC and CEC methods based on the use of MIPs, there is no apparent tailing for the enantiomer peaks, and baseline separation with 25,000-60,000 plate number is achieved. These effects are attributed to reduction of the MIP site heterogeneity by means of peripheral location of the core cross-linked NP and to MIP-binding sites with the same ordered radial orientation. This new MIP approach is based on the substitution of the functional monomers with a surfactant monomer, sodium N-undecenoyl glycinate (SUG) for improved inclusion in the MIP-NP structure and to the use of a miniemulsion in the MIP-NP synthesis. The feasibility of working primarily with aqueous electrolytes (10 mM phosphate with a 20% acetonitrile at pH 7) is attributable to the micellar character of the MIP-NPs, provided by the inclusion of the SUG monomers in the structure. To our knowledge this is the first example of "monoclonal" MIP-NPs incorporated in CEC separations of drug enantiomers.     

Application of Magnetic ordered mesoporous carbon Nanocomposite for the Removal of Ponceau 4R Using Factorial Experimental Design

Silicon - Nanocomposites of ordered mesoporous carbon with silica coated magnetite nanoparticles (Fe3O4@SiO2-CMK-8, MNCs) were synthesized by carbonizing sucrose inside the pores of the Kit-6...     

Optimising space utilisation in block stacking warehouses

Block stacking storage is an inexpensive storage system widely used in manufacturing systems where pallets of stock keeping units (SKUs) are stored in a warehouse at the finite production rates. However, determining the optimal lane depth that maximises space utilisation under a finite production rate constraint has not been adequately addressed in the literature and is an open problem. In this research, we propose mathematical models to obtain the optimal lane depth for single and multiple SKUs where the pallet production rates are finite. A simulation model is used to evaluate performance of the proposed models under stochastic uncertainty in the major production parameters and the demand.     

Hydrothermal Coating of Patterned Carbon Nanotube Forest for Structured Lithium‐Ion Battery Electrodes

Controlling the arrangement and interface of nanoparticles is essential to achieve good transfer of charge, heat, or mechanical load. This is particularly challenging in systems requiring hybrid nanoparticle mixtures such as combinations of organic and inorganic materials. This work presents a process to coat vertically aligned carbon nanotube (CNT) forests with metal oxide nanoparticles using microwave‐assisted hydrothermal synthesis. Hydrothermal processes normally damage delicate CNT forests, which is addressed here by a combination of lithographic patterning, transfer printing, and reduction of the synthesis time. This process is applied for the fabrication of structured Li‐ion battery (LIB) electrodes where the aligned CNTs provide a straight electron transport path through the electrode and the hydrothermal coating process is used to coat the CNTs with conversion anode materials for LIBs. These nanoparticles are anchored on the surface of the CNTs and batteries fabricated following this process show a fourfold longer cyclability. Finally, this process is used to create thick electrodes (350 µm) with a gravimetric capacity of over 900 mAh g^?1.     

Developing a fatigue fracture model for asphalt overlay reinforced with geogrid

This study examines the influence of the most important parameters on delaying reflection cracking in geogrid reinforced overlay in bending mode, employing a large scale experimental set up. The effects of grid stiffness, tensile strength, coating type, amount of tack coat, overlay thickness, crack width and stiffnesses of overlay and existing asphalt concrete on reinforced asphalt overlay was investigated. Results indicate that the cracked layer and overlay moduluses have strongest influence on reduction of reflective cracking. Also, a fatigue fracture model for reflection cracking based on modified Paris law for fracture mechanic model with linear viscoelastic correspondence principle in mode I was developed. It was found that this engineering fracture mechanics model was an efficient method of determining the fatigue damage process. Based on Schapery’s theory, regression equations were developed to estimate fracture parameters. These equations can be used to predict the crack growth rate in the design of asphalt overlay against reflective cracking.     

Top-k dominating queries on incomplete large dataset

Top-k dominating (TKD) query is one of the methods to find the interesting objects by returning the k objects that dominate other objects in a given dataset. Incomplete datasets have missing values in uncertain dimensions, so it is difficult to obtain useful information with traditional data mining methods on complete data. BitMap Index Guided Algorithm (BIG) is a good choice for solving this problem. However, it is even harder to find top-k dominance objects on incomplete big data. When the dataset is too large, the requirements for the feasibility and performance of the algorithm will become very high. In this paper, we proposed an algorithm to apply MapReduce on the whole process with a pruning strategy, called Efficient Hadoop BitMap Index Guided Algorithm (EHBIG). This algorithm can realize TKD query on incomplete datasets through BitMap Index and use MapReduce architecture to make TKD query possible on large datasets. By using the pruning strategy, the runtime and memory usage are greatly reduced. What’s more, we also proposed an improved version of EHBIG (denoted as IEHBIG) which optimizes the whole algorithm flow. Our in-depth work in this article culminates with some experimental results that clearly show that our proposed algorithm can perform well on TKD query in an incomplete large dataset and shows great performance in a Hadoop computing cluster.