Nanotechnology and global energy demand: challenges and prospects for a paradigm shift in the oil and gas industry.

The exploitation of new hydrocarbon discoveries in meeting the present global energy demand is a function of the availability and application of new technologies. The relevance of new technologies is borne out of the complex subsurface architecture and conditions of offshore petroleum plays. Conventional techniques, from drilling to production, for exploiting these discoveries may require adaption for such subsurface conditions as they fail under conditions of high pressure and high temperature. The oil and gas industry over the past decades has witnessed increased research into the use of nanotechnology with great promise for drilling operations, enhanced oil recovery, reservoir characterization, production, etc. The prospect for a paradigm shift towards the application of nanotechnology in the oil and gas industry is constrained by evolving challenges with its progression. This paper gave a review of developments from nano-research in the oil and gas industry, challenges and recommendations

Continuous hydrothermal flow synthesis of S-functionalised carbon quantum dots for enhanced oil recovery

Currently, there is a paucity in the exploration and application of carbon-based nanomaterials for enhanced oil recovery. Carbon quantum dots (CQDs), 0D materials consisting of a graphitic core covered by an amorphous carbon framework, were produced from glucose and p-sulfonic acid calix[4]arene (SCX4) via Continuous Hydrothermal Flow Synthesis (CHFS), an environmentally benign synthetic approach. The S-functionalised carbon quantum dots (S-CQDs) demonstrated excellent colloidal stability in aqueous and brine solutions, low retention on sand surface, and impressive enhanced oil recovery (EOR) of 17% at very low concentrations of 0.01 wt%. The mechanisms proposed for CQDs in increasing oil sweeping efficiency involves altering the carbonate rocks wettability towards water wet, and creating temporary log-jamming, where the ultra-small particle size (1.7 ± 0.7 nm) allows S-CQDs to recover oil trapped in tight reservoirs. The synthesised S-CQDs also demonstrate photoluminescence, pH stability in the range of 3–11 and have excitation independent behaviour (300–360 nm) with an emission peak at 433 nm

Continuum-based models and concepts for the transport of nanoparticles in saturated porous media: A state-of-the-science review

Environmental applications of nanoparticles (NP) increasingly result in widespread NP distribution within porous media where they are subject to various concurrent transport mechanisms including irreversible deposition, attachment/detachment (equilibrium or kinetic), agglomeration, physical straining, site-blocking, ripening, and size exclusion. Fundamental research in NP transport is typically conducted at small scale, and theoretical mechanistic modeling of particle transport in porous media faces challenges when considering the simultaneous effects of transport mechanisms. Continuum modeling approaches, in contrast, are scalable across various scales ranging from column experiments to aquifer. They have also been able to successfully describe the simultaneous occurrence of various transport mechanisms of NP in porous media such as blocking/straining or agglomeration/deposition/detachment. However, the diversity of model equations developed by different authors and the lack of effective approaches for their validation present obstacles to the successful robust application of these models for describing or predicting NP transport phenomena. This review aims to describe consistently all the important NP transport mechanisms along with their representative mathematical continuum models as found in the current scientific literature. Detailed characterizations of each transport phenomenon in regards to their manifestation in the column experiment outcomes, i.e., breakthrough curve (BTC) and residual concentration profile (RCP), are presented to facilitate future interpretations of BTCs and RCPs. The review highlights two NP transport mechanisms, agglomeration and size exclusion, which are potentially of great importance in controlling the fate and transport of NP in the subsurface media yet have been widely neglected in many existing modeling studies. A critical limitation of the continuum modeling approach is the number of parameters used upon application to larger scales and when a series of transport mechanisms are involved. We investigate the use of simplifying assumptions, such as the equilibrium assumption, in modeling the attachment/detachment mechanisms within a continuum modelling framework. While acknowledging criticisms about the use of this assumption for NP deposition on a mechanistic (process) basis, we found that its use as a description of dynamic deposition behavior in a continuum model yields broadly similar results to those arising from a kinetic model. Furthermore, we show that in two dimensional (2-D) continuum models the modeling efficiency based on the Akaike information criterion (AIC) is enhanced for equilibrium vs kinetic with no significant reduction in model performance. This is because fewer parameters are needed for the equilibrium model compared to the kinetic model. Two major transport regimes are identified in the transport of NP within porous media. The first regime is characterized by higher particle-surface attachment affinity than particle-particle attachment affinity, and operative transport mechanisms of physicochemical filtration, blocking, and physical retention. The second regime is characterized by the domination of particle-particle attachment tendency over particle-surface affinity. In this regime although physicochemical filtration as well as straining may still be operative, ripening is predominant together with agglomeration and further subsequent retention. In both regimes careful assessment of NP fate and transport is necessary since certain combinations of concurrent transport phenomena leading to large migration distances are possible in either case

Comparison of a new mass-concentration, chain-reaction model with the population-balance model for early- and late-stage aggregation of shattered graphene oxide nanoparticles

Aggregation as an essential mechanism impacting nanoparticle (NP) functionality, fate, and transport in the environment is currently modelled using population-balance equation (PBE) models which are computationally expensive when combined with other continuum-scale reactive transport models. We propose a new simple mass-concentration-based, chain-reaction modelling (CRM) framework to alleviate computational expenses of PBE and potentially to facilitate combination with other fate, transport, and reaction models. Model performance is compared with analytical PBE solution and a standard numerical PBE technique (fixed pivot, FP) by fitting against experimental data (i.e., hydrodynamic diameter and derived count rate of dynamic light scattering used as a representative of mass concentration) for early- and late-stage, aggregation of shattered graphene oxide (SGO) NP across a broad range of solution chemistries. In general, the CRM approach demonstrates a better match with the experimental data with a mean Nash-Sutcliffe model efficiency (NSE) coefficient of 0.345 than the FP model with a mean NSE of 0.29. Comparing model parameters (aggregation rate constant and fractal dimension) obtained from fitting CRM and FP to the experimental data, similar trends or ranges are obtained between the two approaches. Computationally, the modified CRM is an order-of-magnitude faster than the FP technique, suggesting that it can be a promising modelling framework for efficient and accurate modelling of NP aggregation. However, in the scope of this study, reaction rate coefficients of the CRM have been linked to collision frequencies based on simplified and empirical relationships which need improvement in future studies

The Effectiveness of Training Package based on Executive Functions of Delis-Kaplan on Reading skill of Dyslexic students

Background and Aim: Reading is considered as one of the first ways to acquire knowledge, and students with poor reading skills learn more during and after school. The present research aimed to evaluate effectiveness of training package based on executive functions of Delis-Kaplan on reading skill of dyslexic students. Method: This was quasi-experimental study with pre and post tests and following up. Statistical population was all male and female students in third grade in Tehran who were studying in 2018-19. Thirty dyslexic students were selected by multi- clustering random sampling, then according to inclusion and exclusion criteria, 15 subjects were selected for experimental group and 15 for control group. Experiment group received training package based on executive functions of Delis-Kaplan in 17 sessions each lasting for 60 minutes, but control group did not. The tools used in present research were Raven intelligence test and reading test of Kormi Noori and Moradi (2018). Data were analysed using covariance analysis by SPSS.22. Results: The results showed that training package based on executive functions of Delis-Kaplan has significant effect on reading skill in dyslexic children (p<0/001). Conclusion: According to these results, it can be said that improving executive functions in early years of schooling may improve reading skills of dyslexic student

Physicochemical and cytotoxicity analysis of green synthesis carbon dots for cell imaging

Carbon dots (CDs) have outstanding optical properties, biocompatibility, and photostability, making them attractive for imaging applications. A facile and green one-step hydrothermal synthesis method is proposed, which can be safely used in a wide range of applications such as chemical sensing, bioimaging, and optoelectronics. In this study, we report green synthesis of carbon dots from bitter orange juice (Citrus Aurantium) by hydrothermal treatment for the first time. We studied effects of time, temp erature, and pH on fluorescence of CDs, characterized them using various spectroscopic and microscopic methods, and evaluated their toxicity to different cell lines. Identifying an optimum reaction condition of 180 ºC for 7 h heating gave CDs that showed pH-dependent fluorescence, with the largest fluorescence at a pH of 7.0. The CDs were 1-2 nm in size with a spherical morphology and negative surface charge. The CDs showed a high quantum yield of 19.9 %, reasonable photostability, excellent water solubility, and long fluorescence lifetime. A one step hydrothermal rout led to various hydrophilic functional groups on the surface of the CDs. Our results showed that the CDs were non-toxic over a large concentration range and effective for imaging of cells, indicating their potential as imaging probes in medical diagnostics and biosensor applications