Impact of the Naturally Driven Surfactant in EOR Application: Experimental, Microscopic, and Numerical Analyses.

While synthetic, conventional surfactants have a known negative environmental impact, their high cost poses a significant challenge. In contrast, naturally extracted surfactants are cheaper and are readily available. The applicability of natural surfactants depends on the saponin concentration, extraction, and synthesis methods. Certain parameters, such as their efficiency in obtaining the required interfacial tension (IFT) values, salinity tolerance, and stability under reservoir conditions, must be examined. Kazakhstan produces a substantial quantity of flaxseed, and flaxseed oil is a good source of fatty acids that can be converted to natural surfactants. Therefore, the work aims to identify the potential of the natural-flaxseed oil surfactant. The experimental study evaluated the synthesized surfactant, effective concentration, salinity's effect, interfacial tension, rheology, and oil recovery concerns in vugs limestone. A microscopic study was conducted to provide insight into the flow in the vugus matrix. At the same time, the numerical method was also employed to establish a potential recovery understanding. The Fourier spectrometer results proved the distinct presence of the triterpenoid. The critical micelle concentrations are 6 and 2.5 wt % for solution in 0 and seawater salinity, respectively. The IFT was reduced by 40-48% and is more effective in seawater solutions. The oil additional recovery was 39-50% after surfactants. The presence of a fractured vugus did not affect the success of the application. Despite the difficulty in modeling the system, the numerical results agree with the experiments and show only 7% differences in total recovery. The research offers novel natural surfactants that can be applied in offshore Kazakhstan.

Electrofermentation increases concentration of poly γ-glutamic acid in Bacillus subtilis biofilms.

Fluctuations in redox conditions in bioprocesses can alter the end-products, reduce their concentration, and lengthen the process time. Electrofermentation enables rapid metabolic modulation of biosynthesis and allows control of redox imbalances in biofilm-based fermentation processes. In this study, electrofermentation is used to boost the production of the bacterial biopolymer poly-γ-glutamic acid (γ-PGA) from Bacillus subtilis ATCC 6051. When compared to control experiments (3.3 ± 0.99 g L-1 ), the application of an electrode potential E = 0.4 V versus Ag/AgCl results in a more than two-fold increase in the production of γ-PGA (9.13 ± 1.4 g L-1 ). Using an engineered B. subtilis strain, in which γ-PGA production is driven by isopropyl ß-d-1-thiogalactopyranoside, electrofermentation improves polymer concentrations from 15.4 ± 1.5 to 23.1 ± 1.6 versus g L-1 . These results confirm that electrofermentation conditions can be adopted to increase the concentration of γ-PGA and perhaps other extracellular biopolymers in industrial strains.

A decision tree model for accurate prediction of sand erosion in elbow geometry.

Erosion of piping components, e.g., elbows, is a hazardous phenomenon that frequently occurs due to sand flow with fluids during petroleum production. Early prediction of the sand's erosion rate (ER) is essential for ensuring a safe flow process and material integrity. Some models have been applied to determine the ER of the sand in the literature. However, these models have been created based on specific data to require a model for application to wide-range data. Moreover, the previous models have not studied relationships between independent and dependent variables. Thus, this research aims to use machine learning techniques, namely linear regression and decision tree (DT), to predict the ER robustly. The optimum model, the DT model, was evaluated using various trend analysis and statistical error analyses (SEA) techniques, namely the correlation coefficient (R). The evaluation results proved proper physical behavior for all independent variables, along with high accuracy and the DT model robustness. The proposed DT method can accurately predict the ER with R of 0.9975, 0.9911, 0.9761, and 0.9908, AAPRE of 5.0%, 6.27%, 6.26%, and 5.5%, RMSE of 2.492E-05, 6.189E-05, 9.310E-05, and 5.339E-05, and STD of 13.44, 6.66, 8.01, and 11.44 for the training, validation, testing, and whole datasets, respectively. Hence, this study delivers an effective, robust, accurate, and fast prediction tool for ER determination, significantly saving the petroleum industry's cost and time.

Investigation of Natural Mucilage for Enhanced Oil Recovery: the Potential of Corchorus Olitorius Hydrocolloid.

The need for an effective offshore enhanced oil recovery (EOR) solution led to the focus on natural hydrocolloids. Polysaccharide hydrocolloid research is constantly expanding in a variety of petroleum applications such as drilling, flow assurance, and EOR. Corchorus olitorius is being examined in the present study as a potential natural polymer for chemical flooding. This study investigated the rheology and fluid flow characteristics in porous media, focusing on the effects of the concentration, temperature, and salinity of the fluid. Furthermore, core flooding was carried out to evaluate the potential recovery was characterized and found to contain a significant amount of polysaccharides and cellulose. The rheological behavior demonstrated an increase in viscosity with concentration. The relationship between viscosity and temperature is inversely proportional. Additionally, the mucilage viscosity significantly increased in the presence of 35,000 ppm NaCl, varying from 39 to 48 cp. The improvement of oil recovery by a unit PV injection is around 10 and 20% at 0 and 35,000 ppm of NaCl, respectively. In sandstone with a moderate porosity and permeability, the overall oil recovery ranges between 59 and 70%. C. olitorius has complex polysaccharide/cellulose derivatives that improved rheology and produced results that are promising for future offshore applications.

Evaluation of two commercially available rapid stool antigen tests for the diagnosis of Helicobacter pylori infection.

INTRODUCTION: Helicobacter pylori (H. pylori) is one of the most prevalent infections, which can cause chronic gastritis, peptic ulcers and even gastric cancer. Prompt diagnosis and subsequent eradication are essential. Many commercially available H. pylori stool antigen diagnostic kits are used. However, the diagnostic performance of these tests has not yet been evaluated. This study aimed to evaluate two commercial rapid H. pylori Stool Antigen-Lateral Flow Immunochromatography Assay kits (HpSA-LFIA). METHODOLOGY: A total of 88 adult patients with dyspeptic symptoms were included in the study. Full case history was obtained, and fresh stool samples were tested for HpSA by two different kits: RightSign® (BiotesT, Hangzhou, China) and OnSite® (CTK biotech, Poway, USA) and HpSA-enzyme-linked immunosorbent assay (ELISA) as a reference standard. RESULTS: Of the 88 patients, H. pylori infection was positive in 32 (36.4%), negative in 53 (60.2%), and indeterminate in 3 (3.4%) by ELISA. The sensitivity, specificity, positive predictive value, and negative predictive value were as follows: 96.6%, 66.1%, 62%, and 97.4%, respectively for RightSign® test and 96.9%, 50%, 52.5%, and 96.6%, respectively for OnSite® test. CONCLUSIONS: HpSA-LFIA, RightSign® and OnSite®, are good negative tests, however they cannot be used as a sole test for diagnosis and needs other confirmatory tests in case of positive results.

Handheld echocardiographic screening for rheumatic heart disease by non-experts in rural South Kordofan, Sudan: Supporting task shifting for control of a serious disease.

BACKGROUND: Rheumatic heart disease (RHD) is a major and preventable cause of cardiac morbidity in Sudan. It can be detected early with a handheld echocardiography (HHE) machine. Our study aimed to screen for RHD in rural South Kordofan and to investigate the ability of non-experts to obtain good quality HHE records. METHODS: A cross-sectional study was conducted in South Kordofan, Sudan. A team of non-experts was trained for two weeks on handheld echocardiographic screening for RHD using a simplified protocol. Cases were recorded and reviewed by a pediatric cardiologist. Demographic and clinical features of screened subjects were studied. Descriptive statistics were presented as "number (%)" or "mean ± SD". RHD frequency was expressed as cases per 1000, and the Chi-Square test/Fisher's Exact test was used to compare RHD findings between different groups. RESULTS: A total of 467 subjects were screened. Echocardiographic quality was acceptable in 93% of recorded studies, hence 452 cases were included in the analysis. The disease frequency was found to be 50 per 1000. Out of 452 screened subjects (age 10-25 years), 23 were found to have RHD. The disease was mild in 70% and moderate or involving two valves in 30% of patients. Risk factors for the disease included the father's occupation and the village of residence. CONCLUSION: Shortly trained non-expert medicals can assist in RHD surveillance in remote areas using HHE for early detection and management. South Kordofan state is highly endemic to RHD and a control program needs to be implemented.

Fear of a new pandemic: perception and prediction of monkeypox among the middle east general population.

Background: Monkeypox is a zoonotic disease caused by the monkeypox virus, an Orthopox virus. The 2022 monkeypox outbreak provoked fear among the public. Public awareness about the disease could be an important factor in its control. The authors conducted this study to assess the perception and prediction of monkeypox among the Middle East public. Methods: This cross-sectional study was conducted in August 2022. Data were conveniently collected from eight Middle Eastern countries using an online self-administered questionnaire distributed through educational and social media platforms. Statistical analysis was conducted using R software. Results: Approximately 11 016 individuals participated in this study. The participants' overall knowledge score indicated poor knowledge about monkeypox. Most of the participants knew the causative organism (66.7%). However, numerous participants were not aware of the disease mode of transmission, symptoms, complications, and vaccination. Participants' awareness was mostly gained from social media (61.8%). The majority predicted acquiring monkeypox when protective measures are not taken (72.7%), progression to a pandemic with economic consequences (50.8 and 52%, respectively), and the ability of the Ministry of Health to control the epidemic (51.5%). Conclusion: In the Middle East, public knowledge about monkeypox is poor. Raising awareness about monkeypox would be of benefit in controlling the epidemic. This study constitutes evidence upon which health education programs could be designed.

Management of Helicobacter pylori among medical doctors working in Khartoum, Sudan 2019: a cross-sectional study.

Background: Various international guidelines have been developed regarding Helicobacter pylori (H. pylori) management, as it is infecting more than half of the world's population. Sudan's health system lacks guidelines regarding H. pylori management, leading to a discrepancy in practice. Investigating the current approach could be a step forward in the formulation of a national consensus in the management of H. pylori. Methods: A cross-sectional study was conducted among medical doctors currently working in Khartoum, Sudan. Participants were enrolled from platforms of medical associations through an online questionnaire. The questionnaire was scored out of 25 points, and scoring 13 or above considered a good approach. Data analysis was carried out using Statistical Package for Social Sciences (SPSS). Results: A total of 358 medical doctors participated in the study. The mean (±SD) score was 12.9(±4.5). Those who were using textbooks, campaigns, symposiums or general medical information to their primary Source of knowledge significantly scored higher. The most selected indication for both diagnosis (76.8%) and treatment (67.6%) was an active peptic ulcer. Stool antigen test (SAT) was the most preferred test (70.7%). The majority of respondents selected triple therapy (82.1%) as a first-line regimen. Only 37.7% confirmed the eradication after four weeks of stopping the treatment. They ensure eradication mainly through SAT (29%). Conclusion: A suboptimal approach was noted among medical doctors of Khartoum, Sudan, regarding H. pylori management. Efforts should be invested in forming national guidelines and the implementation of continuous medical education programs.

Toward Reducing Surfactant Adsorption on Clay Minerals by Lignin for Enhanced Oil Recovery Application.

The significant loss of surfactants during reservoir flooding is a challenge in oil field operations. The presence of clay minerals affects the surfactant performance, resulting in surfactant losses. This is because the mineralogical composition of the reservoir results in unpredicted adsorption quantity. Therefore, this paper seeks to investigate Aerosol-OT's adsorption on different quartz/clay mineral compositions during the flow. Also, it investigates adsorption mitigation by preflushing with lignin. The dynamic experiments were conducted on sand packs composed of quartz-sand and up to a 7% clay mineral content. The results obtained from the surfactant losses were compared with/without lignin preflush at different pH values. The main observation was the direct relationship between increasing the composition of clay minerals and the surfactant pore volume required to overcome the adsorption. The highest adsorption calculated was 46 g/kg for 7% kaolinite. Moreover, lignin successfully reduced the adsorption of Aerosol-OT by 60%. Therefore, the results demonstrate that the effects of the clay mineral content on adsorption could be efficiently minimized using lignin at a high pH.

Prevalence and risk factors of Hantavirus infection in patients undergoing hemodialysis in Khartoum, Sudan, in 2019: a cross-sectional study.

BACKGROUND: Hantaviruses are enveloped negative sense RNA viruses that cause hemorrhagic fever with renal syndrome. This study aimed to identify the prevalence of Hantavirus IgG antibodies and possible risk factors for Hantaviruses infections among end-stage renal disease (ESRD) patients attending the Dr Salma dialysis center in Sudan. METHODOLOGY: This was a cross-sectional study in which 91 ESRD patients and 30 healthy plasma samples were screened for Hantavirus IgG antibodies using ELISA. A questionnaire containing sociodemographics, history of rat exposure and clinical data information was filled in by each ESRD patient. RESULTS: In this study, 9 out of 91 ESRD patients (9.9%) tested positive for Hantaviruses antibodies (IgG) while none of the 30 healthy plasma samples showed seropositivity. There was no statistically significant association between age, gender, educational level and rat exposure and Hantavirus infection in ESRD patients (p>0.05). CONCLUSION: This study is the first to be conducted in Sudan regarding Hantaviruses and ESRD. The prevalence of Hantavirus antibodies among ESRD patients is high compared with findings reported in the literature from studies conducted on the same group of patients. It points to an interesting question as to whether Hantaviruses have an association with ESRD but further studies are needed before drawing any conclusions.

Ultrasound-assisted weak-acid hydrolysis of crystalline starch nanoparticles for chemical enhanced oil recovery.

Ascorbic acid was used for the first time to synthesize crystalline starch nanoparticles (CSNP). The physical properties of the CSNP were investigated. Rheological properties of the crystalline starch nanofluid (CSNF) were compared with native cassava starch (CS) and commercial polymer xanthan. Interfacial properties of the CSNF at the interface of oil and water (O/W) were investigated at different concentrations and temperatures. Wettability alteration efficiency of CSNF on oil-wet sandstone surface was investigated using the sessile drop method. Core flooding experiment was conducted at reservoir conditions. The methods were effective in producing spherical and polygonal nanoparticles with a mean diameter of 100 nm and increased in crystallinity of 7%. Viscosity increased with increase in surface area and temperature of the CSNF compared to a decrease in viscosity as the temperature increases for xanthan. Interfacial tension (IFT) decreased with increase in concentration of CSNF, electrolyte and temperature. The results show that CSNF can change the wettability of sandstone at low concentration, high salinity and elevated temperature. Pressure drops data shows stability of CSNF at 120 °C. The formation of oil bank was enough to increase oil recovery by 23%.

Ultrasonic assisted ultrafiltration process for emulsification of oil field produced water treatment.

Ultrafiltration has been proven to be very effective in the treatment of oil-in-water emulsions, since no chemical additives are required. However, ultrafiltration has its limitations, the main limits are concentration polarization resulting to permeate flux decline with time. Adsorption, accumulation of oil and particles on the membrane surface which causes fouling of the membrane. Studies have shown that the ultrasonic is effective in cleaning of fouled membrane and enhancing membrane filtration performance. But the effectiveness also, depends on the selection of appropriate membrane material, membrane geometry, ultrasonic module design, operational and processing condition. In this study, a hollow and flat-sheet polyurethane (PU) membranes synthesized with different additives and solvent were used and their performance evaluated with oil-in-water emulsion. The steady-state permeate flux and the rejection of oil in percentage (%) at two different modes were determined. A dry/wet spinning technique was used to fabricate the flat-sheet and hollow fibre membrane (HFMs) using Polyethersulfone (PES) polymer base, Polyvinylpyrrolidone (PVP) additive and N, N-Dimethylacetamide (DMAc) solvent. Ultrasonic assisted cross-flow ultrafiltration module was built to avoid loss of ultrasonic to the surrounding. The polyurethane (PU) was synthesized by polymerization and sulphonation to have an anionic group (-OH; -COOH; and -SO3H) on the membrane surface. Changes in morphological properties of the membrane had a significant effect on the permeate flow rate and oil removal. Generation of cavitation and Brownian motion by the ultrasonic were the dominant mechanisms responsible for ultrafiltration by cracking the cake layers and reducing concentration polarization at the membrane surface. The percentage of oil after ultrafiltration process with ultrasonic is about 90% compared to 49% without ultrasonic. Ultrasonic is effective in enhancing the membrane permeate flux and controlling membrane fouling.

Synergy of the flow behaviour and disperse phase of cellulose nanoparticles in enhancing oil recovery at reservoir condition.

Ascorbic acid was used for the first time to synthesize cellulose nanoparticles (CNP) extracted from okra mucilage. The physical properties of the CNP including their size distribution, and crystalline structures were investigated. The rheological properties of the cellulose nanofluid (CNF) were compared with the bulk okra mucilage and commercial polymer xanthan. The interfacial properties of the CNF at the interface of oil-water (O/W) system were investigated at different concentrations and temperatures. The effects of the interaction between the electrolyte and ultrasonic were determined. Core flooding experiment was conducted at reservoir condition to justify the effect of the flow behaviour and disperse phase behaviour of CNF on additional oil recovery. The performance of the CNF was compared to conventional EOR chemical. The combined method of ultrasonic, weak-acid hydrolysis and nanoprecipitation were effective in producing spherical and polygonal nanoparticles with a mean diameter of 100 nm, increased yield of 51% and preserved crystallinity respectively. The zeta potential result shows that the CNF was stable, and the surface charge signifies long term stability of the fluid when injected into oil field reservoirs. The CNF, okra and xanthan exhibited shear-thinning and pseudoplastic behaviour. The IFT decreased with increase in concentration of CNF, electrolyte and temperature. The pressure drop data confirmed the stability of CNF at 120°C and the formation of oil bank was enough to increase the oil recovery by 20%. CNF was found to be very effective in mobilizing residual oil at high-temperature high-pressure (HTHP) reservoir condition. The energy and cost estimations have shown that investing in ultrasonic-assisted weak-acid hydrolysis is easier, cost-effective, and can reduce energy consumption making the method economically advantageous compared to conventional methods.

Management of Helicobacter pylori among medical doctors working in Khartoum, Sudan 2019: a cross-sectional study

Background: Various international guidelines have been developed regarding Helicobacter pylori (H. pylori) management, as it is infecting more than half of the world's population. Sudan's health system lacks guidelines regarding H. pylori management, leading to a discrepancy in practice. Investigating the current approach could be a step forward in the formulation of a national consensus in the management of H. pylori. Methods: A cross-sectional study was conducted among medical doctors currently working in Khartoum, Sudan. Participants were enrolled from platforms of medical associations through an online questionnaire. The questionnaire was scored out of 25 points, and scoring 13 or above considered a good approach. Data analysis was carried out using Statistical Package for Social Sciences (SPSS). Results: A total of 358 medical doctors participated in the study. The mean (±SD) score was 12.9(±4.5). Those who were using textbooks, campaigns, symposiums or general medical information to their primary Source of knowledge significantly scored higher. The most selected indication for both diagnosis (76.8%) and treatment (67.6%) was an active peptic ulcer. Stool antigen test (SAT) was the most preferred test (70.7%). The majority of respondents selected triple therapy (82.1%) as a first-line regimen. Only 37.7% confirmed the eradication after four weeks of stopping the treatment. They ensure eradication mainly through SAT (29%). Conclusion: A suboptimal approach was noted among medical doctors of Khartoum, Sudan, regarding H. pylori management. Efforts should be invested in forming national guidelines and the implementation of continuous medical education programs.