bluuebunny/crossref_metadata_2025_split huggingface dataset:
The rheological behavior of a pseudo-oil-based mud formulated with Hura crepitans plant oil as base fluid
Authors: Onuh C. Y. , Dosunmu A. , Anawe P. A. L. , Okoro E. E. , Igwilo K. C. , Ehinmowo A. B. 
Published: July 2019

AbstractThe need to prevent our environment from deterioration caused by toxic waste from drilling mud is a prime objective to the oil and gas industry. The exploration of non-edible plant oil for potential base oil in formulating drilling mud is progressing due to the environmentally friendly nature. This research work involves using a commercial synthetic oil from the oil industry and Hura crepitans oil. This oil samples were used as a base fluid in preparing the mud from which the rheological properties were analyzed. Chemical oil extraction method using soxhlet apparatus was used to extract the oil from H. crepitans seeds; it was then distilled to remove the solvent. The mud samples were formulated with 7 and 9 g concentrations of the viscosifier, and properties were measured at 113 and 158 °F. It was then aged for 16 h at 240 °F, and mud properties were measured before and after hot rolling for comparison. Different rheological models were used to describe the experimental data. The physical properties of the synthetic oil and H. crepitans oil reveal a flash point of 213.8 and 399.2 °F, fire point of 226.4 and 500 °F, viscosity index of 297 and 207, specific gravity/density of 805 and 907, respectively. The mud properties of the synthetic oil-based mud had a better emulsion stability, lower plastic viscosity, higher yield point values, and lower gel strength than the H. crepitans oil-based mud. The rheological properties of synthetic and H. crepitans oil-based mud increase and decrease, respectively, after hot rolling. The optimal concentration of viscosifier was 7 g to have maintained the API acceptable range for the rheological properties. Based on the $$R^{2}$$R2 values, RMSE values, and the fitted plots, Herschel–Bulkley had a better description of the experimental data.
An investigation on the effects of silica and copper oxide nanoparticles on rheological and fluid loss property of drilling fluids
Authors: Medhi Srawanti , Chowdhury Satyajit , Gupta Dharmender Kumar , Mazumdar Aryab 
Published: July 2019

AbstractThe increase in hydrocarbon production from problematic production zones having high fluid loss and formation damage has led to the emergence of non-damaging drilling fluids (NDDF). Recently, nanotechnology has found a wide array of applications in the oil and gas industry. Most applications of nanotechnology and enhancement in properties of drilling fluids are restricted to bentonite, xanthan gum and a few oil-based mud. In this study, the effects of silica and copper oxide nanoparticles on polyamine-based NDDF and conventional bentonite-based drilling fluids (BDF) were investigated. Silica nanoparticles were prepared using sol–gel method, and copper oxide nanoparticles were synthesized using co-precipitation method. Nano-based drilling fluids were prepared by dispersing nanoparticles in concentrations of 0.5%, 0.8% and 1% by weight. Furthermore, testing of these nano-based drilling fluids was conducted by measuring specific gravity, pH, rheological properties and filtrate loss at surface temperature (room temperature) and then aging it at bottom-hole temperature (80 °C). The addition of silica and copper oxide nanoparticles to both the drilling fluids did not show much effect on pH and specific gravity. Addition of 0.5% concentration of silica nanoparticles in NDDF showed least degradation in rheological properties compared to other fluids. It showed reduction in filtrate loss by 31%. Moreover, silica nanoparticles in conjunction with BDF acted as a mud thinner showing a decrease in viscosity and yield point. On the contrary, when used with NDDFs, silica nanoparticles acted as a mud thickener. Copper oxide nanoparticles behaved as a thinner in both the drilling fluids with a highest reduction in plastic viscosity of 24% for 0.8% of copper oxide nanoparticle in BDF. Thinning properties were enhanced as the doping concentrations of copper oxide nanoparticles increased; however, the fluid loss controlling ability decreased except for 0.5% concentration by 31% and 24% when used with both the drilling fluids. Additionally, optimal Herschel–Bulkley parameters have been determined by using genetic algorithm to minimize the function of sum of squared errors between observed values and model equation.
Performance of the injection of different gases for enhanced oil recovery in a compositionally grading oil reservoir
Authors: Pourhadi Sajad , Hashemi Fath Aref 
Published: July 2019

AbstractReservoir fluid characterization is one of the most important steps in hydrocarbon reservoir engineering calculations and studies. The reservoir fluid composition is not constant along the entire hydrocarbon column and varies along the vertical and horizontal directions. In most cases, such variations have been observed along the vertical direction. This is known as compositional grading phenomenon and has a strong impact on the calculation of original hydrocarbon in place, reservoir development, and oil recovery factor. In this paper, a simulation study was carried out to investigate the effects of compositional grading on reservoir fluid properties and the injection of various gases such as carbon dioxide (CO2), nitrogen (N2), associated petroleum gas (APG), N2–CO2mixture, and water-alternating-CO2injection into different depths of a conventional black oil reservoir in the southwest of Iran in order to detect the best injection depth and achieve the highest oil recovery factor. Due to increase in minimum miscibility pressure (MMP) with depth in compositionally grading reservoirs, MMP variations with depth is one of the main challenges in determining the optimal gas injection depth in such reservoirs. The results showed that N2, APG and N2–CO2mixture were immiscibly injected into all depths of the reservoir due to their high miscibility pressures. The occurrence of gas override and channelling phenomena during the course of immiscible gas injection significantly reduced oil displacement efficiency. On the other hand, CO2was miscibly injected to all reservoir layers and revealed a higher efficiency in comparison with the injection of N2, APG and N2–CO2mixture. In fact, better miscibility development was observed in upper reservoir parts, as compared to the lower parts. Through completing injection wells at upper reservoir parts and then injecting gas into these parts, one can thus further enhance oil recovery and extend production plateau. Moreover, the results confirmed that water-alternating-CO2injection into all reservoir depths, compared to other gas injection scenarios, was associated with increased macroscopic sweep efficiency as well as enhanced oil recovery factor.
Determination of sharing oil losses using proportional and stratified methods in Krisna field
Authors: Hermawan Yulius Deddy , Kristanto Dedy , Hariyadi  , Wibowo  
Published: July 2019

AbstractThis paper discusses about the oil losses due to emulsion, flash, and mixing oil phenomena that frequently happened in the oil and gas companies. The goals of this work are to calculate the emulsion and vapor correction volumes, shrinkage correction volume of the mixture of two or more crude oils with different densities, and to compare between the common proportional method that usually utilized in petroleum industries and the new proposed stratified method for determining of sharing oil losses. The mixing of crude oils from 7 shippers in Krisna field would be used as a case study, and the equation of API 12.3 was chosen to calculate a shrinkage correction volume. Oils from shippers S1, S2, and S3 were first mixed together in TANK-1 of the 1st station; the mixed oil of TANK-1 was then transported to the next station and stored in the TANK-2 and mixed with other oils from shippers S4 and S5; and finally, the mixed oil of TANK-2 was transported to the final station and stored in the TANK-3 and mixed with other oils from shippers S6 and S7. The proportional method gave almost the same shrinkage correction factor (SCF) for all shippers about 0.20%, while stratified method resulted SCF in between 0.05 and 0.31%. Based on our analysis, more often oil mixes with others its volume would be more decreased. The stratified method is therefore recommended to determine sharing oil losses since it gives a fair result.
Response characteristics of conductance sensor and optimization of control-drive circuit in horizontal pipes
Authors: Li He , Cui Yongqiang , Li Jun , Zhao Fengda , Kong Weihang , Wang Min 
Published: July 2019

AbstractOil–water two-phase flow in horizontal oil-producing wells with low velocity and high water cut generally presents the phenomenon that the underlayer shows water flow and the upperlayer presents oil flow or a dispersion of oil in water flow. And existing ring-shaped conductance water cut meter cannot obtain the online and real-time response values corresponding to oil field water conductivity in the calculating water holdup procedure. To tackle this issue, this paper designs a mini-conductance probe array (MCPA). In order to further investigate the ability of the total flow rate of the allowable measurement fluid and the parameters valuing of the water cut in horizontal segregated flow, this paper also analyzes the performance of MCPA with different structure parameters in terms of the spatial sensitivity distribution characteristics. Firstly, the geometry model and mathematical model of MCPA are designed, and the MCPA simulation model is analyzed by using the finite element method. Then, the optimum structure parameter results of the sensors are obtained through analyzing the spatial sensitivity distribution characteristics of MCPA in consideration of different distance between the two electrodes and different inner diameters. Lastly, the MCPA different parameters are developed, and experiments are carried out in horizontal multiphase flow experiment facility to analyze spatial sensitivity distribution characteristics of MCPA with different inner diameters on the basis of optimum parameters. Experimental results demonstrated that MCPA with a larger inner diameter would have high measurement accuracy in variation range of water cut, and has a high adaptability in horizontal oil-producing wells with relatively high flow rate and different flow conditions.
Removal Efficiency of Basic Blue 41 by Three Zeolites Prepared from Natural Jordanian Kaolin
Authors: Gougazeh Mousa , Kooli Fethi , Buhl J.-Ch. 
Published: July 2019

AbstractThe conventional method of zeolite synthesis involves an expensive hydrothermal step whereby a mixture of a metakaolinite, sodium hydroxide, and water is preactivated by thermal treatment between 400°C and 1000°C. The objective of the current study was to determine whether Jordanian kaolinite could be converted to zeolite materials without thermal pre-activation. The alkaline hydrothermal transformation of kaolinite into hydroxysodalite (HS) was achieved, then followed by a reaction with citric acid and solid sodium hydroxide to obtain Zeolite A, or by adding solid Na2SiO3 to prepare zeolite X. These materials were tested for their ability to serve as removal agents for Basic Blue 41 (BB-41) dye from artificially contaminated water, at concentrations ranging from 25 to 1000 mg/L. The maximum removal capacities were estimated using the Langmuir model, with a value of 39 mg/g for hydroxysodalite. Zeolite-X achieved the lowest value (19 mg/g). The feasibility of BB-41 removal was deduced from the Freundlich model for the zeolites studied. The reported low-cost method is proposed as an alternative way to reduce the cost of synthesizing zeolite, and the materials were shown to be potential candidates for the removal of BB-41 dye.
Body image and weight management among Hispanic American adolescents: Differences by sport type
Authors: Reina Anita M. , Monsma Eva V. , Dumas Marcus D. , Gay Jennifer L. 
Published: July 2019

ABSTRACTBackgroundAdolescents' body image concerns vary by sex, ages, and participation in different types of sports. Little is known about variability of body image and weight management behaviors by sport type in Hispanic American adolescents. This study examined whether body image distortion and dissatisfaction are associated with weight management behaviors by sex and sport type in Hispanic adolescents.MethodsA sample of 728 Hispanic participants from the United States (61.6% female, Mage = 12.36 ± 2.35) completed the Stunkard Figural Stimuli, reported weight management behaviors and sport participation. Sports were classified as non‐aesthetic (such as soccer), aesthetic (such as cheerleading), or non‐sport participation. Separate multiple linear regression and multinomial logistic regression models were conducted to test adjusted associations between body image dissatisfaction and distortion, and sport type with weight management behaviors.Results and conclusionsParticipants in non‐aesthetic sports (51.2% male) were more dissatisfied with their body image (want to be bigger; B = −0.17; p = .01) and were 1.5 times more likely to use exercise to lose weight than non‐sport participants. Greater body image dissatisfaction increased the likelihood of weight management behaviors. As year in school increased, participants perceived themselves as smaller than their actual BMI and wanted to be smaller. Hispanic females exhibited similar trends to other ethnicities. However, Hispanic males may have interpreted a desire to be “smaller” as a more lean, muscular physique. Subsequent studies should focus on reasons for weight management, and whether those behaviors are healthy.
THE RESERVE UNCERTAINTIES IN THE CHAIN LADDER MODEL OF MACK REVISITED
Authors: Gisler Alois 
Published: July 2019

AbstractWe revisit the “full picture” of the claims development uncertainty in Mack’s (1993) distribution-free stochastic chain ladder model. We derive the uncertainty estimators in a new and easily understandable way, which is much simpler than the derivation found so far in the literature, and compare them with the well known estimators of Mack and of Merz–Wüthrich.Our uncertainty estimators of the one-year run-off risks are new and different to the Merz–Wüthrich formulas. But if we approximate our estimators by a first order Taylor expansion, we obtain equivalent but simpler formulas. As regards the ultimate run-off risk, we obtain the same formulas as Mack for single accident years and an equivalent but better interpretable formula for the total over all accident years.
Control of oblique-type breakdown in a supersonic boundary layer employing streaks
Authors: Sharma Sushank , Shadloo Mostafa S. , Hadjadj Abdellah , Kloker Markus J. 
Published: July 2019

The effectiveness of streak modes in controlling the oblique-type breakdown in a supersonic boundary-layer at Mach 2.0 is investigated using direct numerical simulations. Investigations in the literature have shown the effectiveness of streak modes in delaying the onset of transition dominated by two-dimensional waves, but in oblique breakdown, three-dimensional waves and a strong streak mode dominate the transition process. Paredes et al. (J. Fluid Mech., vol. 831, 2017, pp. 524–553) discussed the possible stabilization of supersonic boundary layers by optimally growing streaks using parabolized stability equations. However, no study has as yet been reported regarding direct nonlinear control of oblique breakdown. This study deals with the effects of large-amplitude decaying streak modes generated by a blowing–suction strip at the wall to control full breakdown in a reference case. Modes with four to five times the fundamental wavenumber are found to be beneficial for controlling the transition. In the first region after the control-mode forcing, the beneficial mean-flow distortion (MFD), generated by inducing the control mode, is solely responsible for hampering the growth of the fundamental-mode. On the whole, the MFD and the three-dimensional part of the control contribute equally towards controlling the oblique breakdown. The results show significant suppression of transition, and substantial improvements have been observed in the levels of the skin-friction coefficient and wall-temperature in comparison to the uncontrolled case. Moreover, refreshing the control using an additional downstream control strip increases the gain. However, the forcing amplitude must be carefully chosen in order not to introduce a generalized inflection point in the spanwise averaged mean flow invoking enhanced disturbance growth.
Serum cholesterol levels preceding to suicide death in Japanese workers: a nested case-control study
Authors: Chen Sanmei , Mizoue Tetsuya , Hu Huanhuan , Kuwahara Keisuke , Honda Toru , Yamamoto Shuichiro , Nakagawa Tohru , Miyamoto Toshiaki , Okazaki Hiroko , Shimizu Makiko , Murakami Taizo , Eguchi Masafumi , Kochi Takeshi , Yamamoto Makoto , Ogasawara Takayuki , Sasaki Naoko , Uehara Akihiko , Imai Teppei , Nishihara Akiko , Hori Ai , Nagahama Satsue , Tomita Kentaro , Konishi Maki , Kabe Isamu , Dohi Seitaro ,   for the Japan Epidemiology Collaboration on Occupational Health Study Group
Published: July 2019

AbstractObjective:To investigate the association between suicide death and serum cholesterol levels as measured at times close to suicide death.Methods:We conducted a nested case-control study of 41 cases of suicide deaths and 205 matched controls with serum total cholesterol (TC) levels till 3 years before suicide death in a large cohort of Japanese workers.Results:Individuals in the lowest versus highest tertile/predefined category of TC in a Japanese working population had a three- to four-fold greater risk of suicide death. Each 10 mg/dl decrement of average TC was associated with an 18% increased chance of suicide death (95% confidence interval, 2–35%). Similar results were found for TC levels at each year.Conclusion:These results suggest that a low serum TC level in recent past is associated with an increased risk of suicide death.
Short-term impact of sucralose consumption on the metabolic response and gut microbiome of healthy adults
Authors: Thomson Pamela , Santibañez Rodrigo , Aguirre Carolina , Galgani Jose E. , Garrido Daniel 
Published: July 2019

AbstractSucralose is an artificial non-nutritive sweetener used in foods aimed to reduce sugar and energy intake. While thought to be inert, the impact of sucralose on metabolic control has shown to be the opposite. The gut microbiome has emerged as a factor shaping metabolic responses after sweetener consumption. We examined the short-term effect of sucralose consumption on glucose homeostasis and gut microbiome of healthy male volunteers. We performed a randomised, double-blind study in thirty-four subjects divided into two groups, one that was administered sucralose capsules (780 mg/d for 7 d; n 17) and a control group receiving placebo (n 17). Before and after the intervention, glycaemic and insulinaemic responses were assessed with a standard oral glucose load (75 g). Insulin resistance was determined using homeostasis model assessment of insulin resistance and Matsuda indexes. The gut microbiome was evaluated before and after the intervention by 16S rRNA sequencing. During the study, body weight remained constant in both groups. Glycaemic control and insulin resistance were not affected during the 7-d period. At the phylum level, gut microbiome was not modified in any group. We classified subjects according to their change in insulinaemia after the intervention, to compare the microbiome of responders and non-responders. Independent of consuming sucralose or placebo, individuals with a higher insulinaemic response after the intervention had lower Bacteroidetes and higher Firmicutes abundances. In conclusion, consumption of high doses of sucralose for 7 d does not alter glycaemic control, insulin resistance, or gut microbiome in healthy individuals. However, it highlights the need to address individual responses to sucralose.
Will farmers fully adapt to monsoonal climate change through technological developments? An analysis of rice and livestock production in Thailand
Authors: Seo S. N. 
Published: July 2019

AbstractThe current paper tackles a critical question in climate change literature of whether farmers will be able to fully adapt to monsoonal climate changes owing to technological developments. Making use of the climate, agricultural and social data of Thailand from 1900 to 2015, this paper estimates a technological change instrumental variable by the growth of the normalized rice yield per hectare of land. The estimation shows that 0.98 of the growth in rice yield can be attributed to technological changes while the rest is accounted for by climate, soils and social factors. In the second stage regressions with the technological change indicator, the paper estimates the normalized numbers of the six most important types of live animals in Thailand: goats, chickens, cattle, sheep, pigs and buffaloes. Over the time period studied, the number of each of these live animals has increased vastly, except for buffaloes. The second-stage regressions show that the growth is largely attributable to technological changes, but monsoonal climate variables such as normalized monsoon precipitation ratio and normalized monsoon temperature are not significant factors. The results indicate that the rate of technological changes is overwhelming the rate of climate change on agriculture in Thailand.
Helminths and microbes within the vertebrate gut – not all studies are created equal
Authors: Cortés Alba , Peachey Laura E. , Jenkins Timothy P. , Scotti Riccardo , Cantacessi Cinzia 
Published: July 2019

AbstractThe multifaceted interactions occurring between gastrointestinal (GI) parasitic helminths and the host gut microbiota are emerging as a key area of study within the broader research domain of host-pathogen relationships. Over the past few years, a wealth of investigations has demonstrated that GI helminths interact with the host gut flora, and that such interactions result in modifications of the host immune and metabolic statuses. Nevertheless, whilst selected changes in gut microbial composition are consistently observed in response to GI helminth infections across several host-parasite systems, research in this area to date is largely characterised by inconsistent findings. These discrepancies are particularly evident when data from studies of GI helminth-microbiota interactions conducted in humans from parasite-endemic regions are compared. In this review, we provide an overview of the main sources of variance that affect investigations on helminth-gut microbiota interactions in humans, and propose a series of methodological approaches that, whilst accounting for the inevitable constraints of fieldwork, are aimed at minimising confounding factors and draw biologically meaningful interpretations from highly variable datasets.