Insight into hydrophobic interactions between methyl ester sulfonate (MES) and polyacrylamide in alkaline-surfactant-polymer (ASP) flooding

2021 ◽  
Author(s):  
Saiful Hafiz Habib ◽  
Dina Kania ◽  
Robiah Yunus ◽  
Badrul Hisham Mohamad Jan ◽  
Dayang Radiah Awang Biak ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Hydrophobic Interactions ◽  
Asp Flooding ◽  
Insight Into ◽  
Alkaline Surfactant Polymer

scholarly journals Insight into the HIV-1 Vif SOCS-box–ElonginBC interaction

Open Biology ◽  
2013 ◽  
Vol 3 (11) ◽  
pp. 130100 ◽  
Author(s):  
Zhisheng Lu ◽  
Julien R. C. Bergeron ◽  
R. Andrew Atkinson ◽  
Torsten Schaller ◽  
Dennis A. Veselkov ◽  
...  
Keyword(s):  
Solution Structure ◽  
Hydrophobic Interactions ◽  
Dynamic Information ◽  
Ubiquitin Ligase Complex ◽  
Biophysical Studies ◽  
Viral Infectivity Factor ◽  
Β Sheet ◽  
Socs Box ◽  
Insight Into ◽  
Hiv 1

The HIV-1 viral infectivity factor (Vif) neutralizes cell-encoded antiviral APOBEC3 proteins by recruiting a cellular ElonginB (EloB)/ElonginC (EloC)/Cullin5-containing ubiquitin ligase complex, resulting in APOBEC3 ubiquitination and proteolysis. The suppressors-of-cytokine-signalling-like domain (SOCS-box) of HIV-1 Vif is essential for E3 ligase engagement, and contains a BC box as well as an unusual proline-rich motif. Here, we report the NMR solution structure of the Vif SOCS–ElonginBC (EloBC) complex. In contrast to SOCS-boxes described in other proteins, the HIV-1 Vif SOCS-box contains only one α-helical domain followed by a β-sheet fold. The SOCS-box of Vif binds primarily to EloC by hydrophobic interactions. The functionally essential proline-rich motif mediates a direct but weak interaction with residues 101–104 of EloB, inducing a conformational change from an unstructured state to a structured state. The structure of the complex and biophysical studies provide detailed insight into the function of Vif's proline-rich motif and reveal novel dynamic information on the Vif–EloBC interaction.

scholarly journals Nonionic Surfactant to Enhance the Performances of Alkaline–Surfactant–Polymer Flooding with a Low Salinity Constraint

2020 ◽  
Vol 10 (11) ◽  
pp. 3752 ◽  
Author(s):  
Shabrina Sri Riswati ◽  
Wisup Bae ◽  
Changhyup Park ◽  
Asep K. Permadi ◽  
Adi Novriansyah
Keyword(s):  
Nonionic Surfactant ◽  
Oil Recovery ◽  
Anionic Surfactant ◽  
Pore Volume ◽  
Salinity Gradient ◽  
Reference Case ◽  
Low Salinity ◽  
Asp Flooding ◽  
Optimum Salinity ◽  
Alkaline Surfactant Polymer

This paper presents a nonionic surfactant in the anionic surfactant pair (ternary mixture) that influences the hydrophobicity of the alkaline–surfactant–polymer (ASP) slug within low-salinity formation water, an environment that constrains optimal designs of the salinity gradient and phase types. The hydrophobicity effectively reduced the optimum salinity, but achieving as much by mixing various surfactants has been challenging. We conducted a phase behavior test and a coreflooding test, and the results prove the effectiveness of the nonionic surfactant in enlarging the chemical applicability by making ASP flooding more hydrophobic. The proposed ASP mixture consisted of 0.2 wt% sodium carbonate, 0.25 wt% anionic surfactant pair, and 0.2 wt% nonionic surfactant, and 0.15 wt% hydrolyzed polyacrylamide. The nonionic surfactant decreased the optimum salinity to 1.1 wt% NaCl compared to the 1.7 wt% NaCl of the reference case with heavy alcohol present instead of the nonionic surfactant. The coreflooding test confirmed the field applicability of the nonionic surfactant by recovering more oil, with the proposed scheme producing up to 74% of residual oil after extensive waterflooding compared to 51% of cumulative oil recovery with the reference case. The nonionic surfactant led to a Winsor type III microemulsion with a 0.85 pore volume while the reference case had a 0.50 pore volume. The nonionic surfactant made ASP flooding more hydrophobic, maintained a separate phase of the surfactant between the oil and aqueous phases to achieve ultra-low interfacial tension, and recovered the oil effectively.

scholarly journals Optimal Design of Alkaline–Surfactant–Polymer Flooding under Low Salinity Environment

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 626 ◽  
Author(s):  
Adi Novriansyah ◽  
Wisup Bae ◽  
Changhyup Park ◽  
Asep K. Permadi ◽  
Shabrina Sri Riswati
Keyword(s):  
Optimal Design ◽  
Weight Ratio ◽  
Linear Alkylbenzene ◽  
Low Salinity ◽  
Salinity Gradients ◽  
Asp Flooding ◽  
Glycol Monobutyl Ether ◽  
Dioctyl Sulfosuccinate ◽  
Hydrolyzed Polyacrylamide ◽  
Alkaline Surfactant Polymer

This paper presents an optimal design of alkaline–surfactant–polymer (ASP) flooding and an experimental analysis on the effects of ASP components under low formation salinity, where the assignment of salinity gradients and various phase types are limited. The phase behavior and coreflooding tests confirmed the ASP formula is optimal, i.e., 1 wt % sodium carbonate (Na2CO3) as the alkaline, 1:4 weight ratio for linear alkylbenzene sulfonate (LAS) and dioctyl sulfosuccinate (DOSS) as a surfactant, 5 wt % diethylene glycol monobutyl ether (DGBE) as a co-solvent, and hydrolyzed polyacrylamide (HPAM) as a polymer. The salinity scan was used to determine that the optimum salinity was around 1.25 wt % NaCl and its solubilization ratio was favorable, i.e., approximately 21 mL/mL. The filtration ratio determines the polymer concentrations, i.e., 3000 or 3300 mg/L, with a reduced risk of plugging through pore throats. The coreflooding test confirmed the field applicability of the proposed ASP formula with an 86.2% recovery rate of residual oil after extensive waterflooding. The optimal design for ASP flooding successfully generated phase types through the modification of salinity and can be applicable to the low-salinity environment.

An insight into the estimation of fatty acid methyl ester based biodiesel properties using a LSSVM model

Fuel ◽  
2019 ◽  
Vol 243 ◽  
pp. 133-141 ◽  
Author(s):  
Razieh Razavi ◽  
Amin Bemani ◽  
Alireza Baghban ◽  
Amir H. Mohammadi ◽  
Sajjad Habibzadeh
Keyword(s):  
Fatty Acid ◽  
Methyl Ester ◽  
Fatty Acid Methyl Ester ◽  
Acid Methyl Ester ◽  
Biodiesel Properties ◽  
Acid Methyl ◽  
Insight Into

Structural insight into the thermostable NADP+-dependentmeso-diaminopimelate dehydrogenase fromUreibacillus thermosphaericus

2015 ◽  
Vol 71 (5) ◽  
pp. 1136-1146 ◽  
Author(s):  
Hironaga Akita ◽  
Tomonari Seto ◽  
Toshihisa Ohshima ◽  
Haruhiko Sakuraba
Keyword(s):  
Main Chain ◽  
Hydrophobic Interactions ◽  
Point Mutations ◽  
Key Factors ◽  
Structural Comparison ◽  
Amino Acid Dehydrogenase ◽  
Large Numbers ◽  
Ureibacillus Thermosphaericus ◽  
Main Factors ◽  
Insight Into

Crystal structures of the thermostablemeso-diaminopimelate dehydrogenase (DAPDH) fromUreibacillus thermosphaericuswere determined for the enzyme in the apo form and in complex with NADP+andN-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid. The main-chain coordinates of the enzyme showed notable similarity to those ofSymbiobacterium thermophilumDAPDH. However, the subunit arrangement ofU. thermosphaericusDAPDH (a dimer) was totally different from that of theS. thermophilumenzyme (a hexamer). Structural comparison with the dimeric enzyme from the mesophileCorynebacterium glutamicumrevealed that the presence of large numbers of intrasubunit and intersubunit hydrophobic interactions, as well as the extensive formation of intersubunit ion-pair networks, were likely to be the main factors contributing to the higher thermostability ofU. thermosphaericusDAPDH. This differs fromS. thermophilumDAPDH, within which the unique hexameric assembly is likely to be responsible for its high thermostability. Analysis of the active site ofU. thermosphaericusDAPDH revealed the key factors responsible for the marked difference in substrate specificity between DAPDH and the D-amino acid dehydrogenase recently created from DAPDH by introducing five point mutations [Akitaet al.(2012).Biotechnol. Lett.34, 1693–1699; 1701–1702].

scholarly journals Variations of Micropores in Oil Reservoir Before and After Strong Alkaline Alkaline-surfactant-polymer Flooding

2016 ◽  
Vol 9 (1) ◽  
pp. 257-267
Author(s):  
Yongqiang Bai ◽  
Yang Chunmei ◽  
Liu Mei ◽  
Jiang Zhenxue
Keyword(s):  
Quantitative Analysis ◽  
Crude Oil ◽  
Oil Recovery ◽  
Chemical Flooding ◽  
Sem Images ◽  
Force Microscopy ◽  
Micropore Structure ◽  
Asp Flooding ◽  
Before And After ◽  
Alkaline Surfactant Polymer

Enhanced oil recovery (EOR) provides a significant contribution for increasing output of crude oil. Alkaline-surfactant-polymer (ASP), as an effective chemical method of EOR, has played an important role in advancing crude oil output of the Daqing oilfield, China. Chemical flooding utilized in the process of ASP EOR has produced concerned damage to the reservoir, especially from the strong alkali of ASP, and variations of micropore structure of sandstones in the oil reservoirs restrain output of crude oil in the late stages of oilfield development. Laboratory flooding experiments were conducted to study sandstones’ micropore structure behavior at varying ASP flooding stages. Qualitative and quantitative analysis by cast thin section, scanning electric microscopy (SEM), atomic force microscopy (AFM) and electron probe X-Ray microanalysis (EPMA) explain the mechanisms of sandstones’ micropore structure change. According to the quantitative analysis, as the ASP dose agent increases, the pore width and pore depth exhibit a tendency of decrease-increase-decrease, and the specific ASP flooding stage is found in which flooding stage is most affective from the perspective of micropore structures. With the analysis of SEM images and variations of mineral compositions of samples, the migration of intergranular particles, the corrosions of clay, feldspar and quartz, and formation of new intergranular substances contribute to the alterations of sandstone pore structure. Results of this study provide significant guidance for further application to ASP flooding.

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