Experimental evaluation of surface treated nanoparticles and their effect on wettability alteration of carbonate surfaces and oil-brine interfacial tension

The alteration of rock surface wettability and the reduction of oil/brine interfacial tension enhances oil recovery from the reservoir. Most of the carbonate rock reservoirs around the world are oil-wet and changing their wettability may enhance oil recovery. Moreover, nanoparticles have presented a promising potential in enhanced oil recovery applications. An experimental study of contact angle changes upon exposure to nanoparticles on carbonate surfaces that are dispersed in brine solution has been conducted using various nanoparticle solutions, some of which were in-house synthesized. Also, interfacial tension measurements and calculations were implemented using the pendant drop method to study the effect of the invading nanoparticles solution. Nanoparticle concentrations were varied and progress was monitored with time. Effects of nanoparticle size, grafting coverage and mixed chemicals as well as observations are discussed. Two hypotheses were proposed for the wettability alteration mechanisms.Petroleum and Geosystems Engineerin

Certainty and Subjectivity in English Education Research: A Cross Cultural Systemic Functional Analysis

This study examines the use of epistemic modality (expressions that signal varying degrees of certainty and subjectivity) by writers of English education research. Epistemic modality is a crucial, yet intricate, rhetorical device through which writers qualify their claims and construct a stance towards their texts and readers. Disciplinary and cultural norms influence the rhetorical use of modality in academic texts. To understand the impact of these contextual factors, linguistic descriptions need to examine discourse produced in individual disciplines and even subdisciplines. Using an exploratory comparative approach, the present study analyzes education research that is produced by native-English-speaking and EFL Arab writers: (1) to describe the discipline-specific practices that are adopted by native writers to manipulate the degrees of certainty and subjectivity in their discourse; and (2) to explore how these practices vary cross-culturally. Sixty research papers are analyzed using the finely grained model of Systemic Functional Linguistics. The findings show a disciplinary preference whereby native writers avoided expressing hesitancy and doubt and preferred a moderately confident epistemic stance to create convincing arguments. These writers’ epistemic style was also objective and detached. The EFL texts, in contrast, were less dialogic and had higher levels of confidence, explicitness, and subjectivity. Although advanced in their linguistic and disciplinary proficiency, the non-native writers displayed some patterns that are generally characteristic of other Arab and non-Arab L2 writers/learners, indicating the vital role that culture and nativeness play in rhetorical strategy use. The paper ends by highlighting the need for explicit instruction of epistemic modality in Arab higher education institutions in order for non-native writers to produce academic texts that are persuasively effective from the perspective of the international academic community

Characterization of the Rate of Injection of Diesel Solenoid Injectors Operated in the Multiple Injection Strategy: A Comparison of the Spray Momentum and Bosch Tube Methods

Multiple injection strategies can be used for controlling the heat release rate in an engine, particularly in compression ignition engines. This can mitigate the heat transfer losses and overcome the limitation related to the maximum pressure allowed for a particular engine. Controlling heat release with repetitive injections requires precise characterization of the fuel injection rates. In such a configuration, the injector used should be characterized for its hydraulic delay, rate of injection, and the effect of dwell timing with multiple injections. This study investigates the fuel injection behavior of a high-flow-rate solenoid injector operated with single and double injections. Two characterization methods, the momentum flux, and the Bosch tube are used and compared to investigate their suitability with the multiple injection strategies. Experiments with single injection are conducted by varying the Energizing Timing (ET) from 0.5 up to 2 ms. The tests with multiple injections (i.e., double injections) are conducted with a fixed ET of 0.5 ms, while the dwell times (δt) are varied from 0.1 up to 1 ms. All tests are performed at 500, 1000, 1500, and 2000 bar rail pressures. Depending on the injection pressure, the injector’s needle could not fully close with short dwell times and the injections are merged. The momentum flux method has faster ramp-up and decaying and more oscillations in the quasi-steady-state phase compared to the Bosch tube method. The effective duration of injection is overpredicted with the Bosch tube method. The momentum flux method is demonstrated to be more suitable for measuring the ROI of multiple injection strategies

The Effect of Styrene-Maleic Acid (SMA) Copolymers on Solubilizing Lipid Bilayers and Forming Nanodiscs

Cell membranes, or plasma membranes, play an essential role in the structure and the function of living cells. In 1972, the fluid mosaic membrane model was the first unifying paradigm of membrane structure. It is no longer considered adequate because evidence of many non-homogeneous lipid structures in both natural and model membranes have been discovered over the past thirty years. The field of membrane biophysics now uses updated versions of the mosaic model, which consists of the complex mixture of different lipid species. The lipid species found in natural membranes produce a range of dynamic, laterally segregated, non-homogeneous domains, which exist on time scales ranging from microseconds to minutes. The cell membrane is an enclosing or separating membrane that acts as a selectively permeable barrier within living things. It consists of the phospholipid bilayer with associated embedded proteins, integral (intrinsic) and peripheral (extrinsic) proteins used for various biological activities. Proteins, especially integral membrane proteins, perform a range of key functions vital to the cell, such as controlled movement of molecules across lipid bilayers, as well as participating in cell signaling and motility. The major obstacle to studying membrane proteins is the tendency for some of their properties to change and the proteins themselves may be denatured when extracted by detergents. One of the most significant approaches to solve this problem is the use of styrene-maleic acid copolymers (SMAs), which offers detergent-free solubilization of embrane, which allows studies of membrane proteins to be done in very small systems. The main goal of this thesis is to examine the effects of these polymers on the interior of the lipid bilayer. With these, membrane proteins can be extracted from cell membranes while conserving a patch of near-native membrane around them. It has been suggested but not proven that proteins in nanodiscs reside in a hydrophobic environment that is identical to that found in the native cell membrane. Moreover, I also investigate the kinetics of membrane solubilization by SMA by using UV/visible spectrophotometer. In addition, I examine how lipid packing in the nanodiscs is affected by the presence of the polymers and how it depends on polymer composition by using SMA variants with different styrene-to-maleic acid ratios

Glycaemic Control, Complications, and Well-Being among People with Type 2 Diabetes in Saudi Arabia

A study was conducted among people with type 2 diabetes in Saudi Arabia to explore prevalence and factors associated with control of the disease, its related macro- and micro-vascular complications, and quality of life. The finding of this study showed that these outcomes are highly prevalent in Saudi Arabia, and modifiable lifestyle factors including healthy diet, regular physical activity, reducing sitting time, and maintaining healthy body weight can lower the risk. A risk scoring tool was developed for diabetes related complications, which will be useful for patients’ counselling and education

CERTAINTY AND SUBJECTIVITY IN ENGLISH EDUCATION RESEARCH: A CROSS CULTURAL SYSTEMIC FUNCTIONAL ANALYSIS

This study examines the use of epistemic modality (expressions that signal varying degrees of certainty and subjectivity) by writers of English education research. Epistemic modality is a crucial, yet intricate, rhetorical device through which writers qualify their claims and construct a stance towards their texts and readers. Disciplinary and cultural norms influence the rhetorical use of modality in academic texts. To understand the impact of these contextual factors, linguistic descriptions need to examine discourse produced in individual disciplines and even subdisciplines. Using an exploratory comparative approach, the present study analyzes education research that is produced by native-English-speaking and EFL Arab writers: (1) to describe the discipline-specific practices that are adopted by native writers to manipulate the degrees of certainty and subjectivity in their discourse; and (2) to explore how these practices vary cross-culturally. Sixty research papers are analyzed using the finely grained model of Systemic Functional Linguistics. The findings show a disciplinary preference whereby native writers avoided expressing hesitancy and doubt and preferred a moderately confident epistemic stance to create convincing arguments. These writers’ epistemic style was also objective and detached. The EFL texts, in contrast, were less dialogic and had higher levels of confidence, explicitness, and subjectivity. Although advanced in their linguistic and disciplinary proficiency, the non-native writers displayed some patterns that are generally characteristic of other Arab and non-Arab L2 writers/learners, indicating the vital role that culture and nativeness play in rhetorical strategy use. The paper ends by highlighting the need for explicit instruction of epistemic modality in Arab higher education institutions in order for non-native writers to produce academic texts that are persuasively effective from the perspective of the international academic community.</jats:p

Audience Awareness, Identity Construction, and Citation Behavior in Arabic and EFL Research

Citations represent an integral interpersonal component of writer-reader dialogic interaction in academic discourse. One under-researched question in citation literature concerns the role of audience as a contextual factor that impacts writers’ citation choices and the nature of the identity and disciplinary knowledge that they construct. The present study adopts a multidimensional analytical approach within a discourse analytic, case-study research design. First, it aims to investigate the citation behavior of five education scholars who are writing research in modern standard Arabic. Second, it examines whether these writers would modify their intertextual style to enact different identity and disciplinary community when writing in English as a foreign language (EFL). Findings revealed a unique character for the Arabic-based citation behavior that contrasted, sometimes, markedly with conventional academic norms, indicating the pivotal role that culture plays in shaping rhetorical preferences. Arabic-based tendencies involved predominance of integral subjective citations, use of combined citations and non-citations, and reliance on what is herein termed intertextual saturation and diffused intertextuality as rhetorical strategies to persuade audience and contract dialogic space. The findings also showed marginal modification of intertextual style in the EFL texts, suggesting lack of significant orientation toward target audiences’ characteristics that would have resulted from enculturation into disciplinary community. The findings imply the overriding need to introduce novice writers to the concept of audience if they are to produce academic discourse that would be deemed interpersonally optimal from the perspective of the international discourse community