bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of replacing conventional feeds with tropical agricultural by‐products on the growth performance, nutrient digestibility and ruminal microbiota of water buffaloes
Authors: Huang Jinhua , Wu Tingting , Sun Xuezhao , Zou Caixia , Yang Yingbai , Cao Yanhong , Yang Yunyan , Wasim Iqbal Muhammad , Lin Bo
Published: April 2020

This study investigated the effect of replacing corn grain, soybean meal and wheat bran with tropical agricultural by‐products, such as palm kernel cake (PKC), cassava residue and dried distiller's grain with solubles (DDGS), on the dry matter intake (DMI), growth performance, apparent nutrient digestibility, ruminal short‐chain fatty acids (SCFA) and ruminal microbial communities of water buffaloes. Thirty healthy 15‐month‐old crossbred water buffaloes with a similar initial body weight of 353.1 ± 23.7 kg were randomly allocated into three dietary experimental groups, and they were fed with same forage but three different concentrates for 50 days fattening. The dietary treatments were as following: typical concentrate (TC, 65% corn + 15% wheat bran + 15% soybean meal), partial replacement concentrate Ⅰ (PRC I, 50% corn + 22.5% corn gluten + 22.5% PKC) and partial replacement concentrate Ⅱ (PRC II, 50% corn + 22.5% cassava residue + 22.5% DDGS). The results showed that the average daily gain of the PRC II group was the highest, and the DMI, acid detergent fibre digestibility and neutral detergent fibre digestibility value of the three groups were different and in the following order: PRC II group > TC group > PRC I group. The crude protein digestibility of PRC II was higher than that of the TC and PRC I groups (p < .05). The ruminal concentrations of total SCFA, acetate, propionate and butyrate of TC group were higher than the other two groups (p < .05). The PRC I group had the highest Bacteroidetes‐to‐Firmicutes ratio (B/F) and relative abundance of the genus Prevotella, while the PRC II group had the lowest B/F and relative abundance of Prevotella. In conclusion, using PKC and corn gluten to completely replace common feed ingredients in the buffalo concentrate ration decreased, while using cassava residue and DDGS increased animal growth performance, mainly due to the different combination influenced nutrient digestibility and ruminal microbial community composition was shifted.
Phylogeography of the mediterranean green seaweed Halimeda tuna (Ulvophyceae, Chlorophyta)
Authors: Rindi Fabio , Pasella Marisa M. , Lee Ming‐Fen E. , Verbruggen Heroen
Published: April 2020

Populations of many Mediterranean marine species show a strong phylogeographic structure, but the knowledge available for native seaweeds is limited. We investigated the genetic diversity of the green alga Halimeda tuna based on two plastid markers (tufA gene and a newly developed amplicon spanning five ribosomal protein genes and intergenic spacers, the rpl2‐rpl14 region). The tufA sequences showed that Mediterranean H. tuna represents a single, well‐defined species. The rpl2‐rpl14 results highlighted a genetic separation between western and eastern Mediterranean populations; specimens collected from widely scattered locations in the Adriatic/Ionian region shared a haplotype unique to this region, and formed a group separated from all western Mediterranean regions. Specimens from Sardinia also formed a unique haplotype. Within the western Mediterranean basin, a gradual shift in the frequency of haplotypes was apparent along a West‐East gradient. Our results represent the first clear evidence of an East‐West genetic cleavage in a native Mediterranean macroalga and offer an interesting perspective for further research into fine‐scale seaweed population structure in the NW Mediterranean Sea.
Recent warming of Tonle Sap Lake, Cambodia: Implications for one of the world’s most productive inland fisheries
Authors: Daly Kensey , Ahmad Shahryar K. , Bonnema Matthew , Beveridge Claire , Hossain Faisal , Nijssen Bart , Holtgrieve Gordon
Published: April 2020

Tonle Sap Lake in Cambodia is arguably the world's most productive freshwater ecosystems, as well as the dominant source of animal protein for the country. The rapid rise of hydropower schemes, deforestation, land development and climate change impacts in the Mekong River Basin, however, now represent serious concerns in regard to Tonle Sap Lake's ecological health and its role in future food security. To this end, the present study identifies significant recent warming of lake temperature and discusses how each of these anthropogenic perturbations in Tonle Sap's floodplain and the Mekong River Basin may be influencing this trend. The lake's dry season monthly average temperature increased by 0.03°C/year between 1988 and 2018, being largely in synchrony with warming trends of the local air temperature and upstream rivers. The impacts of deforestation and agriculture development in the lake's floodplain also exhibited a high correlation with an increased number of warm days observed in the lake, particularly in its southeast region (agriculture R2 = .61; deforestation R2 = .39). A total of 79 dams, resulting in 72 km3 of volumetric water capacity, were constructed between 2003 and 2018 in the Mekong River Basin. This dam development coincided with a decreasing trend in the number of dry season warm days per year in the lower Mekong River, while Tonle Sap Lake's number of dry season warm days continued to increase during this same period. The present study revealed that Tonle Sap Lake's temperature trends are highly influenced by temperature trends in the local climate, agriculture development and deforestation of the lake's watershed. Although there were no noticeable impacts observed from upstream dam development in the Mekong River Basin, local‐to‐regional agricultural and land management of the lake's watershed appear to be effective strategies for maintaining a stable thermal regime in the lake in order to facilitate maximum ecosystem health.
Into the uncanny valley: Simulation versus simulacrum?
Authors: Johnston Jennifer Laura , Kearney Grainne P , Gormley Gerard J , Reid Helen
Published: April 2020

Adding to the Cross‐cutting edge series, Johnston et al. introduce readers to the postmodern concept of the simulacrum and explore its relevance to the growing field of simulation education.
Body Composition Measurements from Birth through 5 Years: Challenges, Gaps, and Existing & Emerging Technologies—A National Institutes of Health workshop
Authors: Gallagher Dympna , Andres Aline , Fields David A. , Evans William J. , Kuczmarski Robert , Lowe William L. , Lumeng Julie C. , Oken Emily , Shepherd John A. , Sun Shumei , Heymsfield Steven B.
Published: April 2020

Body composition estimates are widely used in clinical research and field studies as measures of energy‐nutrient balance, functionality and health. Despite their broad relevance and multiple applications, important gaps remain in techniques available for accurately and precisely quantifying body composition in infants and children from birth through 5 years. Identifying these gaps and highlighting research needs in this age group were the topics of a National Institutes of Health workshop held in Bethesda, MD, USA, 30–31 May 2019. Experts reviewed available methods (multicompartment models, air‐displacement plethysmography, dual‐energy X‐ray absorptiometry, weight‐length and height indices, bioimpedance analysis, anthropometry‐skinfold techniques, quantitative magnetic resonance, optical imaging, omics and D3‐creatine dilution), their limitations in this age range and high priority research needs. A summary of their individual and collective workshop deliberations is provided in this report.
Upregulation of PTTG1 is associated with poor prognosis in prostate cancer
Authors: Fraune Christoph , Yehorov Serhiy , Luebke Andreas M. , Steurer Stefan , Hube‐Magg Claudia , Büscheck Franziska , Höflmayer Doris , Tsourlakis Maria Christina , Clauditz Till S. , Simon Ronald , Sauter Guido , Weidemann Sören , Dum David , Kind Simon , Minner Sarah , Schlomm Thorsten , Huland Hartwig , Heinzer Hans , Graefen Markus , Burandt Eike
Published: April 2020

Pituitary tumor‐transforming gene 1 (PTTG1) is a regulator of chromosome stability. PTTG1 overexpression had been associated with tumor aggressiveness in several cancer types. To examine its prognostic utility in prostate cancer, a tissue microarray including 12 427 tumors with clinical and molecular data was analyzed by immunohistochemistry. PTTG1 immunostaining was largely absent in normal prostate epithelial cells. In cancers, staining was considered weak in 5.4%, moderate in 5.6% and strong in 0.8%. Strong staining was linked to advanced pT stage, high classical and quantitative Gleason grade, high Ki67‐labeling index (all P < 0.0001) and lymph node metastasis (P = 0.0083). The prognostic impact of PTTG1 expression was independent of established preoperative and postoperative prognostic features. Comparison with molecular features revealed that PTTG1 upregulation was associated with nine of 12 common genomic deletions (P < 0.05), p53 alterations and high androgen receptor levels (P < 0.001 each), but was unrelated to the TMPRSS2:ERG fusion status. In conclusion, these data identify PTTG1 as a strong and independent prognostic feature in prostate cancer. PTTG1 measurement, either alone or in combination with other biomarkers might be instrumental for determining prostate cancer aggressiveness.
Enhanced N‐metabolites, ABA and IAA‐conjugate in anthers instigate heat sensitivity in spring wheat
Authors: Bheemanahalli Raju , Impa Somayanda M. , Krassovskaya Inga , Vennapusa Amaranatha R. , Gill Kulvinder S. , Obata Toshihiro , Jagadish S.V. Krishna
Published: April 2020

Unraveling the metabolic and phytohormonal changes in anthers exposed to heat stress would help identify mechanisms regulating heat stress tolerance during the sensitive reproductive stage. Two spring wheat genotypes contrasting for heat tolerance were exposed to heat stress during heading in controlled environment chambers. Anthers were collected from main and primary spikes for metabolic and phytohormonal profiling. A significant reduction in seed set (38%), grain number (54%) and grain weight (52%) per plant was recorded in the sensitive (KSG1177) but not in the tolerant (KSG1214) genotype under heat stress compared to control. Anther metabolite accumulation did not vary quantitatively between main and primary spikes. Hierarchical clustering of the genotypes and treatments using metabolites and phytohormones revealed a distinct cluster for KSG1177 under heat stress from that of control and KSG1214. A significant increase in N‐based amino acids, ABA, IAA‐conjugate and a decrease in polyamines and organic acids were observed in wheat anthers exposed to heat stress. Unlike KSG1214, a significantly higher accumulation of amino acids, ABA and IAA‐conjugate in anthers of the sensitive KSG1177 was recorded under heat stress. These findings provide the rationale and direction towards developing molecular markers for enhancing heat stress tolerance in wheat.
Relations between preschooler social competence and coping tactics during resource‐based conflicts
Authors: Nichols Olivia I. , Vaughn Brian E. , Coppola Gabrielle , Shin Nana , Monteiro Lígia , Krzysik Lisa
Published: April 2020

Although peer conflict is a common experience in preschool classrooms, few studies have examined relations between coping with peer conflict and social competence (SC) in preschool samples. In this study, 166 preschoolers (95 male) were observed during dyadic play episodes designed to induce a resource‐based conflict. Coping tactics were coded using Zimmer‐Gembeck and Skinner’s framework, and their relations with indicators of SC, assessed using direct observations and sociometric interviews, were tested. On average, dyadic play episodes produced 4.19 conflict events per partner, with children’s most common tactics being verbal and/or physical assertions (29% and 17% of all conflict events, respectively). Coping tactics showed moderate correspondence with current taxonomies, and regression analyses with SC demonstrated partial correspondence to studies of older children. Cooperative tactics reflected higher levels of SC, particularly for boys, and failure to cope with the dilemma (i.e., perseveration) reflected lower levels of SC. The use of disengaged tactics was not associated with SC, and only few differences in coping tactic use were associated with the dyad gender composition. Results suggest that coping tactics during resource‐based conflicts among preschoolers are associated with measures of SC and, with slight adjustments, map onto existing frameworks.
Validation of finite‐element models using full‐field experimental data: Levelling finite‐element analysis data through a digital image correlation engine
Authors: Lava Pascal , Jones Elizabeth M. C. , Wittevrongel Lukas , Pierron Fabrice
Published: April 2020

Full‐field data from digital image correlation (DIC) provide rich information for finite‐element analysis (FEA) validation. However, there are several inherent inconsistencies between FEA and DIC data that must be rectified before meaningful, quantitative comparisons can be made, including strain formulations, coordinate systems, data locations, strain calculation algorithms, spatial resolutions and data filtering. In this paper, we investigate two full‐field validation approaches: (1) the direct interpolation approach, which addresses the first three inconsistencies by interpolating the quantity of interest from one mesh to the other, and (2) the proposed DIC‐levelling approach, which addresses all six inconsistencies simultaneously by processing the FEA data through a stereo‐DIC simulator to ‘level' the FEA data to the DIC data in a regularisation sense. Synthetic ‘experimental' DIC data were generated based on a reference FEA of an exemplar test specimen. The direct interpolation approach was applied, and significant strain errors were computed, even though there was no model form error, because the filtering effect of the DIC engine was neglected. In contrast, the levelling approach provided accurate validation results, with no strain error when no model form error was present. Next, model form error was purposefully introduced via a mismatch of boundary conditions. With the direct interpolation approach, the mismatch in boundary conditions was completely obfuscated, while with the levelling approach, it was clearly observed. Finally, the ‘experimental' DIC data were purposefully misaligned slightly from the FEA data. Both validation techniques suffered from the misalignment, thus motivating continued efforts to develop a robust alignment process. In summary, direct interpolation is insufficient, and the proposed levelling approach is required to ensure that the FEA and the DIC data have the same spatial resolution and data filtering. Only after the FEA data have been ‘levelled' to the DIC data can meaningful, quantitative error maps be computed.
Relationships between genome methylation, levels of non‐coding RNAs, mRNAs and metabolites in ripening tomato fruit
Authors: Zuo Jinhua , Grierson Donald , Courtney Lance T. , Wang Yunxiang , Gao Lipu , Zhao Xiaoyan , Zhu Benzhong , Luo Yunbo , Wang Qing , Giovannoni James J.
Published: April 2020

Ripening of tomato fruit is a complex tightly orchestrated developmental process that involves multiple physiological and metabolic changes that render fruit attractive, palatable and nutritious. Ripening requires initiation, activation and coordination of key pathways at the transcriptional and post‐transcriptional levels that lead to ethylene synthesis and downstream ripening events determining quality. We studied wild‐type, Gr and r mutant fruits at the coding and non‐coding transcriptomic, metabolomic and genome methylation levels. Numerous differentially expressed non‐coding RNAs were identified and quantified and potential competing endogenous RNA regulation models were constructed. Multiple changes in gene methylation were linked to the ethylene pathway and ripening processes. A combined analysis of changes in genome methylation, long non‐coding RNAs, circular RNAs, micro‐RNAs and fruit metabolites revealed many differentially expressed genes (DEGs) with differentially methylated regions encoding transcription factors and key enzymes related to ethylene or carotenoid pathways potentially targeted by differentially expressed non‐coding RNAs. These included ACO2 (targeted by MSTRG.59396.1 and miR396b), CTR1 (targeted by MSTRG.43594.1 and miR171b), ERF2 (targeted by MSTRG.183681.1), ERF5 (targeted by miR9470‐3p), PSY1 (targeted by MSTRG.95226.7), ZISO (targeted by 12:66127788|66128276) and NCED (targeted by MSTRG.181568.2). Understanding the functioning of this intricate genetic regulatory network provides new insights into the underlying integration and relationships between the multiple events that collectively determine the ripe phenotype.
Bacterial contamination rates in extracorporeal photopheresis
Authors: Pamler Irene , Richter Eva , Hutchinson James A. , Hähnel Viola , Holler Ernst , Gessner André , Burkhardt Ralph , Ahrens Norbert
Published: April 2020

BACKGROUND

Extracorporeal photopheresis (ECP) is an immunosuppressive treatment that involves leukocyte apheresis, psoralen and UV light treatment, and subsequent reinfusion. Patients treated with ECP are usually immunosuppressed. Bacterial contamination therefore poses a much unwanted risk, but incidence data are lacking.

PATIENTS AND METHODS

We screened all 1922 consecutive ECP procedures scheduled within a roughly 3‐year period for eligibility. Those with missing data on ECP method (inline or offline) or type of venous access (peripheral or central) were excluded. ECPs with complete aerobic and anaerobic microbial testing of baseline patient blood samples (n = 1637) and of ECP cell concentrates (n = 1814) were included in the analysis.

RESULTS

A test for microbial contamination was positive for 1.82% of the cell concentrates, with central venous access was the most significant risk factor for the contamination (odds ratio = 19). Patient blood samples were positive in 3.85% of cases, but no patients became septic. Staphylococcus spp. were most abundant, and products with bacterial contamination did not cause side effects after reinfusion. There were no significant differences in contamination rates between inline and offline ECP.

CONCLUSION

These findings stress the importance of sterile procedures and the benefits of using peripheral over central venous access for reducing the risk of bacterial contamination in ECP.
Simulation of Spray Cooling on Hot Steel Slabs in Continuous Casting
Authors: Ma Haibo , Silaen Armin A. , Zhou Chenn Q.
Published: April 2020

Continuous casting is an important process to solidify molten steel. Efficient and uniform heat removal by water spray without cracking or deforming steel slabs is a major challenge during continuous casting. With the aid of computational fluid dynamics (CFD), the current study presents a numerical model of spray cooling for process understanding and improvement. The Eulerian–Lagrangian approach is utilized to track the movement of water droplets that are injected from a hydraulic nozzle. The initial droplet size is predicted by the linear instability sheet atomization (LISA) model and the droplet distribution satisfies the Rosin-Rammler distribution. Droplet-slab impingement is modeled by the wall jet model and the associated heat transfer accounts for both heat conduction and radiation. Heat transfer coefficient (HTC) on slab surface is validated against a hot-plate benchmark experiment and shows good agreement. The significance of spray standoff distance and spray direction on heat transfer is also investigated. The results indicate the existence of the critical standoff distance beyond which the cooling effect becomes negligible. Spray direction plays an important role in determining the heat transfer rate as well, and insufficient cooling is observed when droplets are sprayed against gravity. Additional 10% to 15% of water will compensate for such low heat transfer. The current study should benefit the steel industry by providing fundamental insights into the process. The current model can also be applied to other types of spray nozzles and can further improve the efficiency of future simulations.
Master Device With Bending Safety for Flexible Surgical Robots
Authors: Ji Daekeun , Shim Seongbo , Kim Seunguk , Joung Sanghyun , Hong Jaesung
Published: April 2020

Flexible robots have been widely studied for application to minimally invasive surgery because of their dexterity and miniaturization ability. Conventional master devices developed to manipulate rigid link-type robots are difficult to apply to flexible robots due to structural difference. In addition, the different kinematic structures of the master device and flexible slave robot cause complex mapping issues. Furthermore, most high-redundancy flexible robots inserted through an over-tube have limited bending angles depending on the insertion depth. Conventional master devices were not designed to comply with this limitation of flexible robots. We developed an isosceles master device that provides intuitive and simple mapping factors for controlling and maintaining the wire tension of a flexible robot in a safe range. We applied a variable isosceles triangle mechanism that structurally limits the bending angle according to the insertion depth. Experimental results showed that our master device can control a flexible slave robot with an error of less than 1.5 mm. Because of the limited bending angle, excessive tension and the resulting damage to the wire were prevented. The isosceles master device can also hold its position and orientation with a passive holding mechanism.
Estimating Effect of Additional Sample on Uncertainty Reduction in Reliability Analysis Using Gaussian Process
Authors: Bae Sangjune , Park Chanyoung , Kim Nam H.
Published: April 2020

An approach is proposed to quantify the uncertainty in probability of failure using a Gaussian process (GP) and to estimate uncertainty change before actually adding samples to GP. The approach estimates the coefficient of variation (CV) of failure probability due to prediction variance of GP. The CV is estimated using single-loop Monte Carlo simulation (MCS), which integrates the probabilistic classification function while replacing expensive multi-loop MCS. The methodology ensures a conservative estimate of CV, in order to compensate for sampling uncertainty in MCS. Uncertainty change is estimated by adding a virtual sample from the current GP and calculating the change in CV, which is called expected uncertainty change (EUC). The proposed method can help adaptive sampling schemes to determine when to stop before adding a sample. In numerical examples, the proposed method is used in conjunction with the efficient local reliability analysis to calculate the reliability of analytical function as well as the battery drop test simulation. It is shown that the EUC converges to the true uncertainty change as the model becomes accurate.
Influence of Ultraviolet Radiation on the Low Velocity Impact Response of Laminated Composite
Authors: Pang Su-Seng , Li Guoqiang , Helms Jack E. , Ibekwe Samuel I.
Published: April 2020

In this study, an E-glass fiber reinforced epoxy composite laminate is subjected to ultraviolet radiation (UV) for up to 48 hours. The intensity of the ultraviolet radiation is 1.5 J/cm2/min. A total of 42 specimens are prepared and tested, in which 6 specimens are used as control and 36 specimens are conditioned. For the conditioned specimens, 18 specimens are exposed to air and 18 specimens are immersed in a water base while subjected to UV radiation. Low velocity impact tests are conducted on the conditioned specimens and control specimens using instrumented drop-weight impact machine. Compression after impact (CAI) tests are conducted using a MTS machine to determine the residual load carrying capacity of the impact damaged specimens. Microscopic observation is conducted to aid in the analysis of the damage mechanism. The test results show that UV radiation alone has a significant effect on reducing the residual load carrying capacity of impact damaged laminated composites. The presence of water enhances the damage effect of UV radiation.
An International Standard (ISO) for GRP Pipelines and Piping Systems
Authors: Frost Simon R.
Published: April 2020

Over the last few years the number of standards relating to the use and implementation of GRP pipelines and piping systems has dramatically proliferated. A working group under ISO TC 67 was formed in an attempt to produce a single international standard with the aim to amalgamate and harmonise the many country wide standards. Standards that were considered in this amalgamation included ASTM F 1173, API 15 HR, BS 7159, ASME B31.3 and the Shell DEP. The work group consisted of members from the oil and gas industry, suppliers and local Health and Safety Executives.

The basis of the document was the old UKOOA specification for the GRP for off-shore systems. The scope of the this new ISO standard was broadened in terms of both application and service conditions.

The new ISO standard comprises 4 sections, scope, qualification, system design and installation/operation. The key points of the sections are;

Qualification procedures are performance based, i.e. the emphasis is on suppliers to demonstrate performance. Care was taken with this new standard to minimise the test burden without compromising on technical rigour.

System design procedures were defined which balanced existing design practices and experience with the limited amount of technical data.

Installation and operational procedures were selected to enhance the use of GRP in many applications. Typical damage mechanisms and defects that could possibly occur were documented with recommendations made of relevant inspection techniques and repair options.

The issue date for this ISO standard is mid 2001.
Detection and Removal of Hydrates by Subsea Thermal Units
Authors: Warren Wayne , Baugh Benton F.
Published: April 2020

A discussion of the potential and test results of detection and removal hydrates from subsea pipelines and completion systems by the direct application of heat by the circulation of locally heated seawater.
Impact of Coiled Tubing Elasticity on Extended Reach Remediation
Authors: Baugh Benton F. , Crawford James R.
Published: April 2020

A discussion of the limitations of coiled tubing extended reach by pushing coiled tubing and the impact of elasticity or recoil of the coiled tubing while attempting to pull coiled tubing out to extended distances.
Review of DeepStar CTR 3202 Testing History
Authors: Baugh Benton F. , Crawford James R.
Published: April 2020

A review of the testing done within the DeepStar CTR 3202 program and some follow-up testing done at the test loop built under the DeepStar program for the development of tooling and methods to facilitate extended reach pipeline blockage remediation.
Development of Two Fluid Model for Pressure Drop Prediction in Two-Phase Vertical Churn Flow
Authors: Putra Satya A. , Christiansen Richard L. , Brill James P.
Published: April 2020

Comprehensive mechanistic models for two-phase flow in pipes have been proposed by several authors. These models predict pressure gradients for bubble, dispersed bubble, churn, slug, and annular flow patterns. The churn flow pressure gradient is often formulated based on a homogeneous model or modification of a slug flow model. A new mechanistic model for churn flow in vertical two-phase flow in pipes has been formulated applying two-fluid model concepts. The two-fluid model for churn flow is developed by defining the mass and momentum balances for gas and liquid phases. An interfacial interaction term is introduced to the balance equations defining the interaction between phases. Pressure drops calculated from this model and other methods available in the literature are compared with measured churn flow data from the Tulsa University Fluid flow Projects (TUFFP) databank. Results show that the proposed churn flow model performs better than all other methods considered.
Flow Patterns in Heavy Crude Oil-Water Flow
Authors: Bannwart Antonio C. , Rodriguez Oscar M. H. , de Carvalho Carlos H. M. , Wang Isabela S. , Vara Rosa M. O.
Published: April 2020

This paper is aimed to an experimental study on the flow patterns formed by heavy crude oil (488 mPa.s, 925.5 kg/m3 at 20 °C) and water inside vertical and horizontal 1 in. pipes. The interfacial tension was 29 dynes/cm. Effort is concentrated into flow pattern characterization, which was visually defined. The similarities with gas-liquid flow patterns are explored and the results are expressed in flow maps of the superficial velocities. In contrast with other studies, the annular flow pattern (‘core annular flow’) was observed in both horizontal and vertical test sections. In fact this flow pattern typically occurs in heavy oil-water flows at low water input fractions. Because of the practical importance of core flow in providing an effective means for heavy oil production and transportation, this paper discusses two criteria that favor its occurrence in pipes.
A New Model for Dispersed Multi-Layer Oil-Water Flow
Authors: Jayawardena Subash S. , Alkaya Banu , Redus Clifford L. , Brill James P.
Published: April 2020

Flow patterns observed in near-horizontal oil-water two-phase flows are quite different from those in gas-liquid flows. Experience with gas-liquid flows suggests that the mechanisms governing the flow behavior are flow-pattern dependent. However, little attention has been given to modeling flow patterns observed only in liquid-liquid systems. Such flow patterns include an oil-in-water dispersion flowing on top of a water layer and the simultaneous flow of dispersions of water-in-oil and oil-in-water as separate layers.

A new mechanistic model is developed for one such flow pattern in horizontal and near-horizontal pipelines. The model combined the two-fluid model used for stratified flows with the homogeneous model used for dispersed flows. This paper presents that model, and shows that the new model can predict the pressure gradient as well as the holdup. The model results are compared with those from two other models, the stratified flow model and the homogeneous model. The new model predictions are also compared with available experimental data.
Development and Implementation of an Environmental Management System for an Oil Company in South Trinidad, in Accordance With the ISO 14001 Standard
Authors: Maharaj Priya S. , Dyal Shyam , Ramnath Kelvin
Published: April 2020

Trinidad and Tobago has the oldest petroleum industry in the world. The activities of this industry have historically impacted the environment and newly drafted environmental rules and regulations of Trinidad and Tobago will require sound environmental management systems by all operating companies in the industry.

In order to meet the challenges of these new regulations, the Petroleum Company of Trinidad and Tobago Limited (Petrotrin) is currently pursuing the development and implementation of an Environmental Management System within its Exploration and Production operations in accordance with the ISO 14001 Standard. This project was initiated in October 1999, and is expected to terminate in December 2001 with international certification.

Petrotrin, realizing the competitive advantages that can result from the integration of an Environmental Management System into its operating systems, has placed the implementation of the EMS as a company strategic goal.

The project was categorized into three main stages: Development, Implementation and Audit/Certification. To date, the Development Stage has been completed and the implementation stage initiated, with the following successes:

• Allocation of manpower resources in the formation of the Steering and Executive Management Committees, and an EMS Project Team;

• Training of project personnel in ISO 14001/10/11/12 Standards;

• Revision of the company Environmental Policy statement;

• Conducting the Gap Analysis Study;

• Development of the Implementation Plan based on the results of the Gap Analysis;

• Initiated the development of the EMS manual and drafted initial procedures as outlined in the Implementation Plan;

• Collection and analysis of data for identification of Significant Environmental Aspects and impacts for Exploration and Production activities.

The Development and Implementation of an Environmental Management System in accordance with the world renowned ISO 14001 is expected to derive many benefits to Petrotrin such as reduced operating costs, improved financial performance, increased access to markets, improved environmental performance, improved community relations, improved customer relations and employee involvement and education.
Environmental Management of Land Subsidence: Compaction Evaluation Through Radioactive Marker Technique
Authors: Macini Paolo , Mesini Ezio
Published: April 2020

Subsidence is a key issue in managing the production of underground fluids, especially in environmentally sensitive areas. This is the case of the Italian Adriatic offshore in front of the historical city of Venice, where several gas fields have been recently discovered. Here, the alleged risks connected with possible land subsidence and coastal impairment are crucial for releasing the authorizations to start a development project. In order to probe such risks, it has been utilized the Radioactive Marker Technique (RMT), nowadays a quite developed method to measure reservoir rock compaction of deep formations, by which it is possible to estimate the uniaxial compressibility coefficients (Cm). As it is well known, Cm is the chief geomechanical parameter influencing compaction phenomena, and thus its evaluation is vital for subsidence predictions by means of mathematical modeling. Generally, Cm can be evaluated by both in-situ and laboratory measurements.

Recent field applications seems to confirm that RMT-derived Cm’s match with sufficient precision with the ones calculated from the surface subsidence observed over the field by means of surveys (levelling, GPS, SAR), but are not always in good agreement with laboratory measurements.

The present study reports some field applications of RMT in the Italian Adriatic offshore, which confirm that Cm’s from laboratory measurements are overestimated with respect to the ones obtained by RMT.
Innovative Approach to the Mercury Control During Natural Gas Processing
Authors: Spiric Zdravko
Published: April 2020

Natural gas, being produced from gas fields around the globe, along with a large number of other harmful substances (CO2, H2S, RSH, COS, etc.), often contains mercury. Mercury’s potentially harmful effect on humans and on the ecological system as a whole as well as the risk regarding mercury’s corrosive effects to the very sophisticated and expensive process material, equipment and catalysts is making its removal an imperative.

The frequently applied procedure to remove mercury as an impurity and environment pollutant from process streams utilizes adsorption on a fixed bed consisting of sulfur impregnated activated carbon.

This paper deals with data, results and more than seven years of practical field experience obtained by research of mercury removal unit efficiency during production and enhancement of natural gas at Molve, Croatia. Paper details the operating implications of handling and processing natural gas containing mercury, showing the results of the innovative approach in the process control, resulting in safety reliability and process efficiency improvements by plant modification due to change of gas flow direction.
Subsurface Transport and Fate of Natural Gas Processing Wastes: Implications for Risk Assessment and Remediation
Authors: Sorensen James , Gallagher John , Hawthorne Steven
Published: April 2020

Fundamental data has been developed regarding the chemical nature and subsurface transport and fate of wastes generated by amine-based gas sweetening and glycol-based dehydration operations. Results indicate the mobility and biodegradability of both amine- and glycol-based wastes are variable depending primarily on soil type. The data suggest 1) a thorough understanding of site-specific waste and subsurface characteristics is necessary when predicting the fate of gas processing wastes, and 2) glycols may act as cosolvents for less mobile, but more highly regulated, hydrocarbons, thereby enhancing their transport. These data must be considered to accurately assess risk and develop appropriate remediation strategies.
Cost-Effective CO2 Sequestration Through Enhanced Oil Recovery
Authors: Rao Dandina N. , Bassiouni Zaki A.
Published: April 2020

The five-year long United Nations campaign for the reduction of greenhouse gases in the atmosphere culminated in the Kyoto protocol of 1997. Since this Kyoto conference attended by nearly 160 nations, sequestration of carbon dioxide from industrial flue gases and its storage and/or utilization have been receiving significantly enhanced attention. According to the US Department of Energy, very little research and development has been done in the United States on promising options that might address CO2 capture, reuse and storage technologies. An exception to this is the utilization of CO2 for enhanced oil recovery. Over a decade of industrial experience has accumulated at more than 70 enhanced oil recovery sites around the world where CO2 is injected to improve oil recovery from waterflooded reservoirs. The accumulated experience in the US, where about 32 million tons of CO2 per year are being utilized in EOR, has amply demonstrated that the retention of CO2 in the reservoir is very high when the original pressure is not exceeded. Thus, CO2 injected enhanced oil recovery presents itself as a mature field-tested technology for sequestering CO2 at a low net cost due to the revenues from recovered oil and gas.

Much of the CO2-EOR experience to date in the US involves the use of high-purity carbon dioxide for conducting miscible floods in conventional crude oil reservoirs. Due to the high costs associated with supplying high-purity CO2 to the reservoir, this process has seen limited commercial success. However, the past research at LSU and elsewhere has amply demonstrated that impure CO2 was also effective in enhancing oil recoveries. This makes the abundant supply of flue gases from fossil-fuel combustion operations a viable and cost-effective option without the need for separating CO2 from the flue gas mixtures. This paper attempts to review and synthesize the literature dealing with geologic sequestration of CO2 in EOR projects. The available data are analyzed both from EOR and CO2 sequestration points of view.
ESP’s Performance With Two Phase and Viscous Flow
Authors: Añez Delso J. , Kenyery Frank , Escalante Sharon I. , Teran Victor M.
Published: April 2020

The free gas presence and the viscous fluids managing have been the two most controversial problems that the production engineer has had to face when selecting an ESP system. Growing demand of this method and failures occurred in Venezuelan wells (Orinoco Belt) have stimulated research on existing equipment and technological alternatives. An experimental test with GC-2900 pump was conducted at INTEVEP’s modified facilities. The experimental matrix included tests at different void fraction and pump intake pressure using air, water and mineral oil (375 Cp). Experimental results and analyses pertaining to the behavior of the pump operating at this condition are presented.
Local Velocity Measurements and Computational Fluid Dynamics (CFD) Simulations of Swirling Flow in a Cylindrical Cyclone Separator
Authors: Erdal Ferhat M. , Shirazi Siamack A.
Published: April 2020

Local measurements and 3-D CFD simulations in Gas-Liquid cylindrical Cyclone (GLCC©) separators are scarce. The main objective of this study is to conduct local measurements and 3-D CFD simulations to understand the swirling flow behavior in a cylindrical cyclone with one inclined tangential inlet. Axial and tangential velocities and turbulent intensities across the GLCC© diameter were measured at 24 different axial locations (12.5″ to 35.4″ below the inlet) by using a Laser Doppler Velocimeter (LDV). The liquid flow rate was 72GPM, which corresponds to an average axial velocity of 0.732 m/s and Reynolds number of 66,900. Measurements are used to create color contour plots of axial and tangential velocity and turbulent kinetic energy. Color contour maps revealed details of the flow behavior. Additionally, 3-D CFD simulations with different turbulence models are conducted. Simulations results are compared to LDV measurements.
The Kvaerner Multiphase Pump System for Deepwater Applications
Authors: Jahnsen Ove F. , Yardley John , High Geoff , Thorkilsen Brede
Published: April 2020

This paper describes Kvaerner’s prototype subsea multiphase pump system and the DEMO 2000 development program (current test completion date 2nd Q2001). Reference is also made to service proven sub-systems, components and subsea expertise incorporated into the pump module and system design. Availability and reliability consideration together with novel plans for the future is presented.

The Subsea Multiphase Pump and motor are packaged into a modular system solution that is readily adaptable to template and manifold configurations and maximises the use of existing qualified components and sub-systems. A guidewireless system is adopted and Kvaerner’s design ensures self-alignment upon installation at simple flowbase interfaces, making it ideal for deepwater applications. Due to the individual 40 tonne weight, and moonpool dimensions, of both flow base and pump module, light monohull vessels can be utilised to execute installation and retrieval.

The pump unit is Bornemann twin-screw design, service proven and modified for subsea use up to 2000-meter water depth, driven by an oil-filled Loher electric motor that provides efficient power with corresponding low weight. Some main pump features are flexible operation covering all gas-liquid ratios together with tolerance for slug flow and some sand. Of particular importance, compared to centrifugal pump designs, the twin-screw volumetric arrangement is able to maintain the pressure boost specification independent of gas content at the pump inlet, and without an upstream mixing tank.
Comparison of the Performance of Drag Reducing Agent Between 2.5 cP Oil and 6.0 cP Oil in Multiphase Flow in Horizontal Pipes
Authors: Kang C. , Jepson W. P.
Published: April 2020

Experimental studies have been performed in a 10 cm diameter, 36 m long, multiphase flow loop to examine the effect of drag reducing agents using 6 cP oil. Studies were performed for superficial liquid velocities of 0.5, 1.0 and 1.5 m/s and superficial gas velocities between 2 and 12 m/s. Carbon dioxide was used as the gas phase. The drag reducing agent (DRA) concentrations were 20 and 50 ppm. The system was maintained at a pressure of 0.13 MPa and a temperature of 25 °C. The comparison of the conditioning of flow with DRA between 2.5 cP oil and 6 cP oil is presented.

The results show that pressure drop in both 2.5 cP oil and 6 cP oil was reduced significantly in multiphase flow with addition of DRA. A DRA concentration of 50 ppm was more effective than 20 ppm DRA for all cases.

As the oil viscosity was increased from 2.5 cP to 6 cP oil, the transition to annular flow was observed to occur at lower superficial gas velocities.

For slug flow and lower superficial gas velocities, the effectiveness in 2.5 cP oil was much higher than that in 6 cP oil with addition of DRA. However, for higher superficial gas velocities, the effectiveness in both oils was similar. For annular flow, the effectiveness in 2.5 cP oil was higher than in 6 cP oil with 50 ppm DRA.

At low superficial gas velocities, DRA in 2.5 cP oil was more effective in reducing the slug frequency. This led to a higher average pressure drop reduction in 2.5 cP oil. However, at higher superficial gas velocities, the slug frequency decreased in both oils almost the same magnitude.
Gas-Liquid Cylindrical Cyclone (GLCC©) Compact Separators for Wet Gas Applications
Authors: Wang Shoubo , Gomez Luis E. , Mohan Ram S. , Shoham Ovadia , Kouba Gene E.
Published: April 2020

Gas-Liquid Cylindrical Cyclone (GLCC©1) separators are becoming increasingly popular as attractive alternatives to conventional separators as they are simple, less expensive, have low-weight, and require little maintenance. However, present studies focus on GLCC designs and applications at relatively lower gas velocities (below the minimum velocity for onset of liquid carry-over in the form of mist flow). With appropriate modifications GLCCs can be used for wet gas and high gas oil ratio (GOR) applications, characterized by higher gas velocities, to knock out the liquid droplets from the gas core. The objectives of this study are to design a novel GLCC capable of separating liquid from a wet gas stream; conduct experimental investigations to evaluate the GLCC performance improvement in terms of operational envelope for liquid carryover; and, measure the liquid extraction from the gas stream. Specific design guidelines for wet gas GLCC are also formulated based on the experimental studies. This investigation provides new capabilities for compact separators for wet gas and high GOR (exceeding 90%) applications.
Comparison of the Method of Cells With the Mori-Tanaka in Predicting Damaged Elasto-Plastic Behavior of Laminated Composite Materials
Authors: Deliktas Babur , Voyiadjis George Z.
Published: April 2020

Two commonly used micromechanical methods, namely the method of cell and the Mori-Tanaka averaging scheme are compared in this work. Their performance is evaluated in the reference to the mechanical behavior of the composite materials. Their respective homogenization schemes are compared and evaluated through the respective strain concentration tensors that are governed by these models. The damaged elasto plastic behavior of the laminated composite system (90)(8s) and (0/90)(4s) are analyzed and compared for the two methods for the case of uniaxial loading. The Lagoudas et. a (1991) modification of the Mori-Tanaka scheme as applied to elasto-plastic constitutive models is used in this work.
Fiber Breakage in Plain Woven Glass Fabric Composites Under Tension/Shear Biaxial Cyclic Stress
Authors: Maeyama Hiroyuki , Okubo Kazuya , Fujii Toru
Published: April 2020

Fiber breakage occurring in fiber bundles of plain-woven glass fabric composites is investigated under tension/shear biaxial cyclic stress. The experimental results show an existence of the strong effect of biaxial stress ratio on fiber breakage and its accumulation. Under pure tension (uniaxial) loading, the variation of fiber breakage ratio with respect to loading cycles is divided into two stages in the longitudinal fiber bundles. In the first stage, the fiber breakage scarcely occurs. In the final stage, fibers in a fiber bundle are broken remarkably. Under the biaxial cyclic stress, the fiber breakage in the longitudinal fiber bundle is observed in initial fatigue stage. In the case of the biaxial stress with large shear stress component, the fiber breakage is also observed in the transverse fiber bundle. The fiber breakage is accelerated by the combined stress with large shear stress component, which is called the shear constraint effect.