Sharif Digital Repository

In the preceding Comment, Drs Tsige and Guo compare their findings about the θ-temperatures of linear chains, ring polymers and poly[n]catenanes with those of previous work by us [Z. A. Dehaghani, I. Chubak, C. N. Likos and M. R. Ejtehadi, Soft Matter, 2020, 16, 3029-3038] and point out that the ordering they obtain for these three quantities is, for large degrees of polymerisation, the reverse of the one we had found in our own investigations. We thank the authors of the Comment for their remarks and we appreciate their detailed investigations, which emphasise the importance of understanding the properties of topological polymers and their behaviour under varying solvent quality. We point... 

Asphaltene precipitation is a major assurance problem posing significant technical and economic loss on petroleum industry. To tackle this issue, various treatments have been proposed and applied by industry. Amongst, inhibiting or retarding the asphaltene precipitation has been understood as the most efficient approach. In this regard, blending crude oil with chemical additives could appreciably heighten its stability. Surfactants, owing to amphiphilic nature, could keep asphaltene dissolved in crude oil by precluding self-tendency of those particles to making agglomerates. Despite importance of this subject, there is still lack of sufficient experimental data to evaluate effectiveness of... 

Nanoemulsion is a novel type of emulsified solutions holding great promises for utilizing in industrial applications. Although microemulsions have been the subject of numerous studies in past decades, however, nanoemulsions are quite virgin and merit detailed investigation to scrutinize their characteristics specific to reservoir engineering, in particular, Enhanced Oil Recovery (EOR). To this end, the present study is an attempt to evaluate the effectiveness of a specific nanoemulsion for oil displacement through porous media. In this regard, flooding experiments were designed and Hexa decyl trimethylammonium bromide (CTAB), which is a cationic surfactant, was used as the emulsifying agent.... 

Despite previous researches on ion-engineered waterflooding (IEWF), its underlying mechanisms are not fully understood, particularly in presence of additives, like surfactants. This paper concerned with the contribution of Ca 2+ , Mg 2+ , SO 4 2- and Na + into altering wettability of oil-wet carbonate minerals towards water preferred state. As a mechanistic study, an experiment workflow was conducted to probe the impact of ions' concentrations in SW, either with or without sodium dodecylbenzene sulfonate (SDBS) which is an anionic surfactant. At first, contact angle (CA) measurement was carried out to evaluate the degree of wettability reversal upon treating the oil-aged calcite slabs with... 

This paper concerns extending applicability of Dehaghani association equation of state (in short DA-EOS) to model non-ideality in phase behavior caused by hydrogen bonding. Advantageously, this equation only needs two and one parameters to treat self- and cross association, respectively, which were determined for methanol/water and ethanol/water mixture in this study. In this respect, DA was coupled with PR and SRK EOS to account for physical interaction between molecules. Notably, DA-PR persistently provides more accurate prediction than DA-SRK for both aqueous methanol and ethanol solutions  

The present study examined the effects of auxetic shoes on the biomechanics of the spine, as compared to barefoot and conventional shoe conditions, during gait and drop vertical jump (DVJ) activities using a combined in vivo and musculoskeletal modeling approach. Motion and force-plate data as well as electromyographic (EMG) activities of select trunk muscles of 11 individuals were collected during foregoing activities. In DVJ activity, two main phases of first landing (FL) and second landing (SL) were studied. In the FL phase of DVJ noticeable alternations were observed when auxetic shoes were used. That is, compared to the conventional footwear condition, smaller EMG activities in extensor... 

A new dibenzothiophene (DBT) desulfurizing bacterium was isolated from oil-contaminated soils in Iran. HPLC analysis and PCR-based detection of the presence of the DBT desulfurization genes (dszA, dszB and dszC) indicate that this strain converts DBT to 2-hydroxybiphenyl (2-HBP) via the 4S pathway. The strain, identified as Rhodococcus erythropolis SHT87, can utilize DBT, dibenzothiophene sulfone, thiophene, 2-methylthiophene and dimethylsulfoxide as a sole sulfur source for growth at 30 °C. The maximum specific desulfurization activity of strain SHT87 resting cells in aqueous and biphasic organic-aqueous systems at 30 °C was determined to be 0.36 and 0.47 μmol 2-HBP min-1 (g dry cell)-1,... 

This research aims to propose a thermodynamic model for predicting asphaltene precipitation upon diluting a crude oil with a paraffinic solvent. To this end, a thorough mathematical formulation was carried out to derive a novel micellization model based on the associative properties of asphaltenic compounds. It was assumed that asphaltenes exist in the oil both as monomeric molecules and aggregated cores; with stabilization latter by attachment of resin on its periphery. The aggregation equilibrium was established by taking into account asphaltene's lyophobic tendency, heat of resin adsorption, and interfacial tension between micelle and oil media which is the main driving factor... 

Molecular dynamics (MD) simulation was utilized to study the role of asphaltene extracted from Gachsaran (an Iranian oilfield) at the synthetic oil-water interface. In agreement with experimental data, IFTs predicted by MD simulation for heptol/brine system showed a minima at around 50 vol.% n-heptane, reflecting the highest contribution of asphaltene into the interface. At greater n-heptane fractions, IFT was increased steadily. Simulation results suggest the asphaltene propensity for remaining in the bulk heptol phase rather related to the fraction of toluene in the mixture. Heptol ingredients, i.e., toluene and heptane, act differently with respect to asphaltene, where former tends to... 

We investigate the effects of topological constraints in catenanes composed of interlinked ring polymers on their size in a good solvent as well as on the location of their θ-point when the solvent quality is worsened. We mainly focus on poly[n]catenanes consisting of n ring polymers each of length m interlocked in a linear fashion. Using molecular dynamics simulations, we study the scaling of the poly[n]catenane's radius of gyration in a good solvent, assuming in general that Rg ∼ mμnν and we find that μ = 0.65 ± 0.02 and ν = 0.60 ± 0.01 for the range of n and m considered. These findings are further rationalized with the help of a mean-field Flory-like theory yielding the values of μ =... 

An algorithm has been developed to investigate the effect of asphaltene precipitation on calculation of minimum miscibility pressure (MMP), which is one of the key design parameters of any gas injection projects. In fact, this algorithm is the extension of procedure suggested by Jaubert et al. for prediction of MMP whatever the displacement mechanism. The vapor-liquid equilibrium calculation and then liquid-liquid equilibrium calculation are required to be taken account to estimate the amount of asphaltene precipitation. The association equation of state (AEOS) has been applied to determine the phase behavior of asphaltene. The algorithm has been used for the MMP prediction of Weyburn... 

Nanoporous boron nitride (BN) nanosheets are promising reverse-osmosis membrane materials, suitable for the removal of hazardous heavy metals, with advantages such as separation energy efficiency, eco-friendliness, heat resistance, acid resistance, and good antifouling properties. BN slit membranes (BNSMs) are a special class of nanoporous BN membranes that have not yet been extensively explored for heavy metal ion separation. To address the existing knowledge gap regarding these membranes, molecular dynamics (MD) simulations were performed herein to investigate the performance of BNSMs in purifying water from arsenic (As3+) and mercuric (Hg2+) cations, as well as chloride (Cl-) anions. For... 

This research aims to present asphaltene fraction of oil by FTIR spectrum technique. For this purpose, three different oil samples with various SARA contents and almost identical API degrees were utilized in this research. Two asphaltenic oil samples were referred to as ‘A’ and ‘B’, and the aliphatic oil sample was named as ‘C’. First of all, the asphaltene fraction was extracted through the IP-143 test. The possible chemical bonds and functional groups were identified through NMR tests. Then, the FTIR spectrums of the oil samples and the extracted corresponding asphaltene fractions were taken. The interpretations were used to find the functional groups in the FTIR of the oil samples that... 

Despite many attempts to study the interaction of fluids in low-salinity flooding, they do not examine the principles of interphasic transition phenomena. This study aims to provide a new understanding of liquid–liquid interactions during the low-salinity water interaction through a series of experiments on the oil, emulsion, and aqueous phase. Three samples of crude oils with different asphaltene concentrations and structures with known physical properties are in contact with different solutions. The brine pH, conductivity, and crude oil viscosity experiments before and after contacting the oil with brine showed that the heteroatom concentration and compaction of crude oil asphaltene... 

As digital technology has developed, relays have evolved from simple electro-mechanical devices into robust microprocessor-embedded intelligent electronic devices (IEDs). Distance protection, one of the most important and sophisticated forms of substation protection, quickly and selectively detects and clears phase faults in sub-transmission and transmission lines. The installation of a substation automation system (SAS) involves implementing control, monitoring, and protection logic by programming the IEDs and providing an appropriate communication network. IEC61850 has gradually satisfied the need for a standard communication protocol so that IEDs from different manufacturers can... 

In this study, the effect of utilization of a nanostructured nickel based material as a negative electrode on the performance of microfluidic microbial fuel cell (MFC) with Escherichia coli as biocatalyst has been investigated. Designing the microfluidic MFC with nickel nanostructure resulted in a higher volumetric power density of 343 W m−3 compared to the previously published results. The assessment of effective parameters on the electrochemical performance of cell was investigated. The investigation of the hydraulic diameter impact on the power generation proves that reducing the microchannel hydraulic diameter from 1000 to 350 μm minimized the internal mass-transfer resistance, and... 

Cotton contributes 0.6% to the value added in GDP and 3.1% to the value added in the agriculture sector of Pakistan. The dusky cotton bug (DCB), Oxycarenus hyalinipennis (Hemiptera: Lygaeidae), is among the insect pest species of highest economic significance in cotton production in the country. Adults and nymphs feed on seeds and cotton bolls, affecting seed germination. The dusky cotton bug is a polyphagous insect that feeds on a variety of host plants. Its adults and nymphs typically feed on squares of the cotton plant, resulting in a pale yellow color of squares and subsequent shedding of infested squares. Insecticide resistance in cotton insect pests is an emerging threat to sustainable... 

This paper aims to establish a panoramic foundation for investigating the impact of sunlight on a recently formulated water-based tri-nano hybrid Sutterby liquid (TNHF) under provided magnetic field, directed through photovoltaic solar panels by exploiting the knacks of machine intelligent computing paradigm. The comparative performance of hybrid and tri-nano fluidic system with water as a base fluid is exhaustively analyzed and discussed. This research is unique, as it has a distinguished figurative comparison analysis between two different types of nanofluidic materials, which helps to choose the best one for use in agrivoltaics systems, and replace the materials already in use to enhance...