bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atomic Force Microscopy Investigation of Protein Adsorption on Hydrogenated Amorphous Carbon
Authors: Mughal Muhammad Zeeshan , Lemoine Patrick , Lubarsky Gennady 
Published: April 2013

ABSTRACTProtein adsorption is the first phenomenon which occurs at nanoscale level when a given surface came into contact with a living fluid cell such as blood. Investigation of this adsorption at nanoscale provides useful information about kinetics and mechanism of conformation of proteins on a given surface. The present study investigates the adsorption of proteins using tapping/intermittent mode atomic force microscopy (T-AFM). The approach taken here is that hydrogenated amorphous carbon coating (a-C:H) is used as a model surface because it is amorphous, smooth, inert and hydrophobic. Two proteins namely albumin and fibrinogen in phosphate buffer (PBS) and de-ionized water are drop casted to study the adsorption kinetics. First and second resonance AFM data was used to investigate the adsorbed layer of proteins. AFM force curve and scratch experiment were used to verify the adhesion and thickness of the adsorbed layer. Combination of height, phase images along with the AFM force curve and scratch experiment shows inhomogeneous distribution of albumin protein in phosphate buffer compared to other protein solutions.
Nanopatterning and plasmonic properties of plasma sputtered gold on diatom frustules
Authors: Romann Julien , Einarsrud Mari-Ann 
Published: April 2013

ABSTRACTBio-silica nanostructures from diatoms (called frustules) featuring plasmonic gold nanoparticles (NPs) are elaborated using two methods based on plasma sputtering of gold. The first investigated method uses a thermal treatment to induce the thermal dewetting of a plasma sputtered gold layer on the diatom frustules. The second method first consists of coating the frustules with polyethylene glycol before sputtering gold on these frustules. For both methods, the amount of gold appears to be a key parameter regarding the final obtained layer, which can either be nanostructured by cavities or consist in individual gold NPs. For an amount of sputtered gold equivalent to form a 5 nm thick layer, both methods allow obtaining diatom frustules covered by gold NPs with a size around 20 nm and a narrow size distribution. The UV-visible characterization of the diatom frustules featuring gold NPs highlights a plasmon extinction band in agreement with individual gold NPs with a size below 25 nm.
Theoretical Evaluation of Oxidation Rate of Zr
Authors: Yamamoto Yasunori , Morishita Kazunori , Iwakiri Hirotomo , Kaneta Yasunori 
Published: April 2013

ABSTRACTFirst principle calculations were performed to evaluate stress effect on the diffusion process of oxygen vacancy in ZrO2 film, and oxidation rate of Zr was evaluated by solving simple diffusion equations. Our calculation results have indicated that both the vacancy formation and migration energies of ZrO2 increase with increasing compressive applied stress. The energy increase causes a decrease in the diffusion coefficient of oxygen vacancy in ZrO2, leading to a decrease in oxidation rate of Zr. The stress effect on diffusion process may explain the experimental fact that Zr is oxidized in proportion to the cubic root of time.
Efficient Solution Techniques for Multiscale Structural Optimization in Materials Science
Authors: Petrova Svetozara I. 
Published: April 2013

ABSTRACTWe consider the modeling and simulation of multiscale phenomena which arise in finding the optimal shape design of microcellular composite materials with heterogeneous microstructures. The paper focuses on the solution of the resulting partial differential equation (PDE) constrained structural optimization problem and development of efficient multiscale numerical algorithms which are challenging tools in reducing the computational complexity. The modeling strategy is applied in materials science for microstructural ceramic materials of multiple constituents. Our multiscale method is based on the efficient combination of both macroscopic and microscopic models. The homogenization technique based on the concept of strong separation of scales and the asymptotic expansion of the unknown displacements is applied to extract the macroscopic information from the microscale model.In the framework of all-at-once approach we find a proper combination of the iterative procedure for the nonlinear problem arising from the first order necessary optimality conditions, also known as Karush-Kuhn-Tucker (KKT) conditions, and efficient large-scale solvers for the stress-strain constitutive equation. We use the path-following predictor-corrector schemes by means of Newton's method and fast multigrid (MG) solution techniques. The performance of two preconditioners, incomplete Cholesky (IC) and algebraic multigrid (AMG), for the resulting homogenized state equation is studied. The comparative analysis for both preconditioners in terms of number of iterations and computing times is presented and discussed. Our interests focus on the parallel implementation of the preconditioning techniques and the use of BoomerAMG as a part of the free software library Hypre developed at the Center for Applied Scientific Computing (CASC), Lawrence Livermore National Laboratory (LLNL).
Graphene-like nanostructures obtained from Biomass
Authors: Barin Gabriela Borin , Santos Yane Honorato , Rocha Jennyfer Alves , Pereira da Costa Luiz , Souza Filho Antônio Gomes , de Fátima Gimenez Iara , Barreto Ledjane Silva 
Published: April 2013

ABSTRACTTwo dimensional (2D) carbon nanomaterials such as few graphite layers or graphene are extensively studied due to their unique properties suitable to be exploiting in a wide range of technological applications. Recently, the growth of high quality graphene monolayers using insects and waste as carbon precursors was reported in the literature. This methodology opened a new way to convert the waste carbon into a high-value-added product. In the present work coconut coir dust, an agroindustrial biomass, was used as biotemplate for preparing carbonaceous materials. Carbon structures were synthesized through pyrolysis under nitrogen atmosphere (100mL/min) at 500, 1000, and 1500°C during 2 hours. Starting materials were coconut coir dust in natura and coconut coir dust hydrothermally treated. The samples were characterized by X-ray diffraction, Raman Spectroscopy, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Raman spectra showed the D band for all samples, related to the presence of defects in sp2 carbon structure and G band, indicative of graphite crystallites. It was also observed that the sample carbonized at 1500°C from coconut coir dust treated by hydrothermal method showed G’ band at 2685cm-1 associated with the stacking order along the c-axis. X-ray diffraction analysis showed a broad peak around 2θ= 22° related to the presence of amorphous carbon. By increasing the pyrolysis temperature changes in XRD diffractograms were observed and the sample which was pyrolysed at 1500°C from coconut coir dust hydrothermally treated showed peaks at 2θ= 26.5°, 43° e 45° assigned to (002), (100) (101) graphite plans, respectively. Scanning electron microscopy images showed the presence of overlapping sheets and plates. Transmission Electron Microscopy (TEM) images of coconut coir dust in natura unveiled the formation of amorphous sheet. Coconut coir dust in natura and treated by the hydrothermal method pyrolysed at 1500°C, lead to the formation of some graphitic domains and few graphene layers.
Microcalorimetric Determination of the Effects of Amoxicillin, Metronidazole, and Their Combination on In Vitro Biofilm
Authors: Astasov‐Frauenhoffer Monika , Braissant Olivier , Hauser‐Gerspach Irmgard , Weiger Roland , Walter Clemens , Zitzmann Nicola U. , Waltimo Tuomas 
Published: April 2013

Background: The mechanism of action of adjuvant antibiotic therapy in the treatment of peri‐implantitis is not well understood. The aim of this study is to investigate antibiotic susceptibility of an in vitro biofilm by isothermal microcalorimetry (IMC).Methods: Titanium disks containing a 72‐hour three‐species biofilm (Streptococcus sanguinis DSM20068, Fusobacterium nucleatum ATCC10953, and Porphyromonas gingivalis DSM20709) were placed in a series of IMC ampoules with nutrient agar supplemented with increasing concentrations of amoxicillin, metronidazole, or their combination and incubated anaerobically for 10 days. Lag time and maximum growth rate were determined from continuous heat‐flow recordings of metabolic activity. To validate the IMC biofilm results, adherent S. sanguinis and P. gingivalis were incubated anaerobically in medium supplemented with antibiotics at 37°C for 24 hours, and their vitality was determined by live/dead staining, conventional culturing, and IMC.Results: In all biofilm samples incubated with antibiotics, a prolonged lag phase was observed compared with controls (P <0.05). Maximum growth rate was significantly lower for samples treated with either amoxicillin or metronidazole compared with controls (P <0.05). Combining the antibiotics did not improve this effect. Concentrations exceeding 10 times the minimum inhibitory concentration completely inhibited the growth of adherent S. sanguinis and P. gingivalis, whereas lower concentrations resulted in only a delay in the lag phase. A poor correlation was observed between live/dead staining and conventional culturing.Conclusions: IMC gives new evidence about antibiotic effects on oral biofilms and is more informative than conventional culture and live/dead assays. The combination of antibiotics was found to be more efficient than metronidazole alone; however, only minor differences in growth inhibition were detected compared with amoxicillin alone.
The Maladies of Water and War: Addressing Poor Water Quality in Iraq
Authors: Zolnikov Tara Rava 
Published: April 2013

Water is essential in providing nutrients, but contaminated water contributes to poor population health. Water quality and availability can change in unstructured situations, such as war. To develop a practical strategy to address poor water quality resulting from intermittent wars in Iraq, I reviewed information from academic sources regarding waterborne diseases, conflict and war, water quality treatment, and malnutrition. The prevalence of disease was high in impoverished, malnourished populations exposed to contaminated water sources. The data aided in developing a strategy to improve water quality in Iraq, which encompasses remineralized water from desalination plants, health care reform, monitoring and evaluation systems, and educational public health interventions.
Trauma Deserts: Distance From a Trauma Center, Transport Times, and Mortality From Gunshot Wounds in Chicago
Authors: Crandall Marie , Sharp Douglas , Unger Erin , Straus David , Brasel Karen , Hsia Renee , Esposito Thomas 
Published: April 2013

Objectives. We examined whether urban patients who suffered gunshot wounds (GSWs) farther from a trauma center would have longer transport times and higher mortality.Methods. We used the Illinois State Trauma Registry (1999–2009). Scene address data for Chicago-area GSWs was geocoded to calculate distance to the nearest trauma center and compare prehospital transport times. We used multivariate regression to calculate the effect on mortality of being shot more than 5 miles from a trauma center.Results. Of 11 744 GSW patients during the study period, 4782 were shot more than 5 miles from a trauma center. Mean transport time and unadjusted mortality were higher for these patients (P < .001 for both). In a multivariate model, suffering a GSW more than 5 miles from a trauma center was associated with an increased risk of death (odds ratio = 1.23; 95% confidence interval = 1.02, 1.47; P = .03).Conclusions. Relative “trauma deserts” with decreased access to immediate care were found in certain areas of Chicago and adversely affected mortality from GSWs. These results may inform decisions about trauma systems planning and funding.
Estimation of Distribution Algorithms Applied to History Matching
Authors: Abdollahzadeh Asaad , Reynolds Alan , Christie Mike , Corne David , Williams Glyn , Davies Brian 
Published: April 2013

Summary
The topic of automatically history-matched reservoir models has seen much research activity in recent years. History matching is an example of an inverse problem, and there is significant active research on inverse problems in many other scientific and engineering areas. While many techniques from other fields, such as genetic algorithms, evolutionary strategies, differential evolution, particle swarm optimization, and the ensemble Kalman filter have been tried in the oil industry, more recent and effective ideas have yet to be tested. One of these relatively untested ideas is a class of algorithms known as estimation of distribution algorithms (EDAs). EDAs are population-based algorithms that use probability models to estimate the probability distribution of promising solutions, and then to generate new candidate solutions. EDAs have been shown to be very efficient in very complex high-dimensional problems.
An example of a state-of-the-art EDA is the Bayesian optimization algorithm (BOA), which is a multivariate EDA employing Bayesian networks for modeling the relationships between good solutions. The use of a Bayesian network leads to relatively fast convergence as well as high diversity in the matched models. Given the relatively limited number of reservoir simulations used in history matching, EDA-BOA offers the promise of high-quality history matches with a fast convergence rate.
In this paper, we introduce EDAs and describe BOA in detail. We show results of the EDA-BOA algorithm on two history-matching problems. First, we tune the algorithm, demonstrate convergence speed, and search diversity on the PUNQ-S3 synthetic case. Second, we apply the algorithm to a real North Sea turbidite field with multiple wells. In both examples, we show improvements in performance over traditional population-based algorithms.
Impact of Reservoir Permeability on Flowing Sandface Temperatures: Dimensionless Analysis
Authors: App J.F.. F. , Yoshioka K.. 
Published: April 2013

Summary
Layer flow contributions are increasingly being quantified through the analysis of measured sandface flowing temperatures. It is commonly known that the maximum temperature change is affected by the magnitude of the drawdown and the Joule-Thomson expansion coefficient of the fluid. Another parameter that strongly impacts layer sandface flowing temperatures is the layer permeability. Aside from determining the drawdown, the layer permeability also affects the ratio of heat transfer by convection to conduction within a reservoir. The impact of permeability can be represented by the Péclet number, which is a dimensionless quantity representing the ratio of heat transfer by convection to conduction. The Péclet number is directly proportional to reservoir permeability. Through dimensionless analysis, it will be shown that for a given drawdown (based on a dimensionless Joule-Thomson expansion coefficient JTD) the temperature change diminishes at low Péclet numbers and increases at high Péclet numbers. This implies that for low-permeability reservoirs such as shale gas or tight oil, the temperature changes will be minimal (less than 0.1ºF) despite the large drawdowns in many instances. Dimensionless analysis is performed for both steady-state and transient thermal models. Results from multilayer transient simulations illustrate the ability to identify contrasting permeability layers on the basis of the Péclet number effect.
Estimation of the Formation Rate Constant of Methane Hydrate in Porous Media
Authors: Fukumoto Ayako , Sato Toru , Kiyono Fumio , Hirabayashi Shinichiro 
Published: April 2013

Summary
Hydrate formation and the relevant mass and heat transfers were numerically analyzed in a microscopic computational domain in which spherical glass beads, water, and methane gas were distributed separately. A hydrate-formation experiment was also carried out by use of a cylindrical pressure cell. The temperature in the cell was controlled by Peltier devices, which were attached to the outer walls of the cell to imitate the adiabatic boundary condition present in the numerical simulation. By history matching between the experiment and calculation, we first obtained a hydrate-formation rate constant per unit volume of water, assuming homogeneous nucleation. Then, after converting the rate by use of a surface-area model of water in porous media, we noted that the area-based rate constant and activation energy of the hydrate formation were estimated to be 6.33 × 1034 mol·m–2 Pa–1 s–1 and 238 × 103 J/mol, respectively, for temperatures of 1.5 to 3.4°C.
Acid Stimulation Learnings from an Unconventional Reservoir
Authors: Popa Andrei , Sivakumar Kailash , Hao Minshen , Cassidy Steve 
Published: April 2013

Abstract
The California's Monterey formation is thought to hold significant hydrocarbon potential and is looked upon as a long term opportunity for development. Given its unique depositional environment, digenesis and very low permeability the hydrocarbon bearing formations have been referred as unconventional reservoirs. Since early 1900's the San Joaquin Valley's Monterey formation has been targeted and produced by several determined and ambitious operators. Still today, these operating companies are trying to develop an understanding of how to best develop and economically unlock this potential to further exploit the resource.
Different stimulation techniques, such as hydraulic fracturing and acid treatments, have been used in an attempt to unlock the resource. It was observed that, while hydraulic fracturing was to some extent effective in several fields, other reservoirs have been found to respond very well to acidizing treatments. The wealth of acid treatment data and corresponding production response from the Monterey formations present a great analysis opportunity to identify best practices and optimize well completions to maximize production.
This paper presents a study undertaken to analyze the acid stimulation treatments in one of the structures of the Monterey formation and consists of two parts. The first part covers the descriptive analysis and involves the use of supervised and unsupervised clustering techniques to evaluate the relationship between acid treatments and production data. Its objective is to understand the success of the treatments and to identify acid job best practices. In the second part, using only the available information and cluster knowledge extracted, an attempt was made to develop a predictive tool to forecast the performance of new/infill wells and re-stimulation treatments.
The study revealed a relatively good understanding of the factors affecting the production response of individual wells and also the variations observed in the different parts of the field. Shortly after the completion of the study, the operating company executed similar activities to what the study found, unbeknownst to the authors. The positive results achieved were not only a validation of the recommendations but also demonstrated the business value created by such analyses.
Environmentally Acceptable Corrosion Inhibitor for Filter-Cake Removal System
Authors: Misra Garima , Kumar Arunesh 
Published: April 2013

Abstract
The production of hydrocarbons with minimum drawdown pressure requires removal of the filter cake formed during overbalanced drilling. In such an operation, the delayed-breaker system used consists of an acid precursor that reacts slowly with water in the carrier brine and releases a strong organic acid, which dissolves the soluble part of the filter cake. However, exposure of downhole tools to acid at elevated temperature and pressure conditions can exacerbate the corrosion potential. Tool corrosion can lead to costly delays related to mechanical failure and workover operations.
Corrosion inhibitors are used to help minimize the impact of acids on metals. Stringent environmental regulations have increased industry emphasis on environmentally acceptable corrosion inhibitors, which not only provide good corrosion protection, but can be disposed of easily with minimal impact on the environment. As an example, North Sea environmental regulations are considered the benchmark for ecotoxicity and biodegradability parameters.
This study describes the corrosion protection potential of different food grade products. Experiments were conducted at 150 and 200°F using steel coupons and varying exposure times. Corrosion loss for different food grade products was less than 0.05 lbm/ft2 after 24 hr. No signs of pitting or crevice formation were observed on the metal coupons. After initial testing, products were screened for further investigation. Corrosion experiments conducted on steel grade metal with a food grade product from the legume family at 150°F resulted in a corrosion loss of 0.02 lbm/ft2 after seven days. Addition of corrosion inhibitor intensifier (CII), even at lower concentrations, enhanced the performance of inhibitors and made them suitable for higher-temperature applications. Corrosion experiments were also performed in the presence of calcium carbonate particles to simulate filter cake. Good inhibition was observed. A comparison of different food grade products applied as corrosion inhibitors and the practical limitations of these products is presented in this paper.
Effects of Wetting Behaviour on Residual Trapping in CO2-Brine Systems
Authors: Soroush Mansour , Wessel-Berg Dag , Kleppe Jon 
Published: April 2013

Abstract
After injecting CO2 into the formations containing brine, it starts to penetrate to upper sections and will be trapped under a geological barrier, during this period the formation brine will imbibe the CO2 and some portion of it will be trapped in the pore spaces. Capillary forces prevent complete drainage of CO2 and residual saturation remains trapped in the pores. Wetting behaviour of the CO2-brine system and relative permeability to each of the phases are important modeling parameters in this phenomenon. In such a system with cycling behaviour, hysteresis in relative permeability has strong effect on trapping. There are debates on wetting behaviour of candidate formations for CO2 storage. Different wettability conditions of the formations, affect the residual trapping mechanism. In this study, theoretical concept of residual trapping is defined through flow equations, and the effect of wettability is discussed by conceptual models. To verify the theoretical concept, different wettability conditions are modeled based on the Utsira formation of Sleipner reservoir and also the Viking formation (Canadian brine formation). Hysteresis in relative permeability and capillary pressure is considered in the modeling of both cases.
Results indicate that different wettability cases including strongly water wet to intermediate and slightly water wet condition, gives variation in the predicted trapped volume of CO2. This variation is from about 2 to 13% in different scenarios of this case study. Results of the simulations verify that wettability behaviour has both short and long term consequences in CO2 trapping. In low permeability simulation case, residual CO2 volume is more sensitive to the wettability condition. Results are dependent on the choice of hysteresis models but wetting behaviour of the system is the main subject that is targeted in this study.