bluuebunny/crossref_metadata_2025 huggingface dataset:
Randomised controlled trial: Shoulder–umbilicus length versus body weight measurement for optimal endotracheal tube depth estimation in ventilated infants
Authors: Mat Ali Adam Al‐Anas bin , Nasir Ariffin , Ramli Noraida , Ibrahim Nor R , Van Rostenberghe Hans
Published: December 2019

Aim

The optimal placement of the endotracheal tube (ETT) in ventilated infants is essential, but birthweight may be not the best parameter to predict it. The aim of this study was a direct comparison of shoulder–umbilical length (experimental group) versus birthweight (control group) as predictor of optimal ETT placement in Malaysian ventilated infants.

Methods

All infants requiring ventilation in the neonatal intensive care unit of a tertiary hospital in Malaysia during the 4‐month study period were eligible to enter this randomised controlled trial. All participants were randomised into two groups: experimental and control group. The main outcome measure was malposition of the ETT (requiring adjustment), as seen on the chest X‐ray performed within 1 h after intubation. Tube placement was assessed by two neonatologists, blinded to the allocation.

Results

One hundred and ten infants were randomised, 55 in each group. The ETT was malpositioned in 13 of 55 infants (23%) for the experimental group and 22 of 55 infants (40%) in the control group (P = 0.06).

Conclusion

In the experimental group, fewer infants showed a need for tube adjustment than in the control group. While a larger study may be necessary to show statistical significance, the difference shown in this study may be large enough to be of clinical significance.
Associations of subclinical atherosclerosis with nonalcoholic fatty liver disease and fibrosis assessed by non‐invasive score
Authors: Xin Zhuojun , Zhu Yuanyue , Wang Shuangyuan , Liu Shanshan , Xu Min , Wang Tiange , Lu Jieli , Chen Yuhong , Zhao Zhiyun , Wang Weiqing , Ning Guang , Bi Yufang , Xu Yu , Li Mian
Published: December 2019

Background & Aims

Nonalcoholic fatty liver disease (NAFLD) has been considered as a risk factor of adverse cardiovascular prognosis, but the relationship between subclinical atherosclerosis and NAFLD remains controversial. We aimed to investigate the impact of subclinical atherosclerosis on incident NAFLD and liver fibrosis.

Methods

We included 3433 subjects aged ≥40 years and free of NAFLD. Brachial‐ankle pulse wave velocity (ba‐PWV) and carotid intima‐media thickness (CIMT) were measured at baseline to assess subclinical atherosclerosis status. At follow‐up visit, NAFLD was diagnosed by hepatic ultrasound and fibrosis was assessed by NAFLD fibrosis score (NFS), fibrosis‐4 score (FIB‐4) and aspartate aminotransferase to platelet ratio index (APRI).

Results

A total of 654 (19.1%) subjects developed NAFLD during the follow‐up period of 4.3 years. In the multivariate logistic regression models, each standard deviation (SD) increment of ba‐PWV was associated with 20% (95% confidence interval [CI] 1.07‐1.33), 22% (95% CI 1.08‐1.39), 17% (95% CI 1.04‐1.32) and 37% (95% CI 1.07‐1.75) higher risk of incident NAFLD, higher NFS, FIB‐4 and APRI respectively. Compared with the lowest quartile of ba‐PWV, the highest quartile ba‐PWV had 63% (95% CI 1.20‐2.22), 112% (95% CI 1.42‐3.17), 86% (95% CI 1.28‐2.69) and 201% (95% CI 1.29‐7.04) higher risk of incident NAFLD, higher NFS, FIB‐4 and APRI respectively. Besides, per SD increase of CIMT was associated with a 12% (95% CI 1.01‐1.24) higher risk of incident NAFLD.

Conclusions

Increased ba‐PWV was independently associated with incident NAFLD and higher probability of fibrosis, whereas CIMT was associated with incident NAFLD but not with fibrosis.
Ear mite infection is associated with altered microbial communities in genetically depauperate Santa Catalina Island foxes (Urocyon littoralis catalinae)
Authors: DeCandia Alexandra L. , Brenner Lara J. , King Julie L. , vonHoldt Bridgett M.
Published: December 2019

The host‐associated microbiome is increasingly recognized as a critical player in health and immunity. Recent studies have shown that disruption of commensal microbial communities can contribute to disease pathogenesis and severity. Santa Catalina Island foxes (Urocyon littoralis catalinae) present a compelling system in which to examine microbial dynamics in wildlife due to their depauperate genomic structure and extremely high prevalence of ceruminous gland tumors. Although the precise cause is yet unknown, infection with ear mites (Otodectes cynotis) has been linked to chronic inflammation, which is associated with abnormal cell growth and tumor development. Given the paucity of genomic variation in these foxes, other dimensions of molecular diversity, such as commensal microbes, may be critical to host response and disease pathology. We characterized the host‐associated microbiome across six body sites of Santa Catalina Island foxes, and performed differential abundance testing between healthy and mite‐infected ear canals. We found that mite infection was significantly associated with reduced microbial diversity and evenness, with the opportunistic pathogenStaphylococcus pseudintermediusdominating the ear canal community. These results suggest that secondary bacterial infection may contribute to the sustained inflammation associated with tumor development. As the emergence of antibiotic resistant strains remains a concern of the medical, veterinary, and conservation communities, uncovering high relative abundance ofS. pseudintermediusprovides critical insight into the pathogenesis of this complex system. Through use of culture‐independent sequencing techniques, this study contributes to the broader effort of applying a more inclusive understanding of molecular diversity to questions within wildlife disease ecology.
Gut permeability is affected by sex and increased in children with irritable bowel syndrome but not in functional abdominal pain
Authors: Shulman Robert J. , Devaraj Sridevi , Heitkemper Margaret
Published: December 2019

Background

Gut permeability is increased in some children and adults with irritable bowel syndrome (IBS). We investigated whether this also is true for children with functional abdominal pain (FAP). We also determined whether sex affected permeability results.

Methods

Sucrose, lactulose, mannitol, and sucralose were ingested after an overnight fast in well‐phenotyped children with IBS (n = 95), FAP (n = 25), and healthy controls (HC) (n = 60). Urine was collected for 24 hours. Percent sucrose recovery was calculated based on the 0‐ to 3‐hour collection; lactulose/mannitol ratio both on the 0‐ to 3‐hour and 0‐ to 24‐hour collections; and percent sucralose recovery on the 0‐ to 24‐hours collection.

Key Results

Age was similar among the groups (P = .26). The lactulose/mannitol ratio was increased in IBS compared with HC at 0‐3 and 0‐24 hours (P = .023, P = .05, respectively). Percent sucralose recovery was greater in FAP than in HC (P = .045). No differences were noted among the groups in percent sucrose recovery. Taking sex into account, percent sucrose recovery was greater in girls with IBS vs HC girls (P = .008). The lactulose/mannitol ratio was greater in boys with IBS compared with HC boys at both time points (both P = .02). Percent sucralose recovery was greater in boys with IBS than in FAP or HC (both P < .001).

Conclusions and Inferences

Sex is a critically important factor when measuring gut permeability. Boys with IBS have increased lactulose/mannitol ratios and percent sucralose recovery. Girls with IBS have increased percent recovery of sucrose. Children with FAP do not demonstrate abnormal gut 0permeability even taking sex into account.
Treosulfan‐based reduced toxicity hematopoietic stem cell transplantation in X‐linked agammaglobulinemia: A cost‐effective alternative to long‐term immunoglobulin replacement in developing countries
Authors: Vellaichamy Swaminathan Venkateswaran , Uppuluri Ramya , Patel Shivani , Melarcode Ramanan Kesavan , Ravichandran Nikila , Jayakumar Indira , Vaidhyanathan Lakshman , Raj Revathi
Published: December 2019

X‐linked agammaglobulinemia (XLA) is a primary antibody disorder due to a mutation in the Bruton tyrosine kinase gene that requires lifelong immunoglobulin replacement resulting in a significant economic burden and treatment abandonment. Hematopoietic stem cell transplantation (HSCT) offers an alternative option for complete cure. In our series, two children with XLA underwent successful HSCT using a myeloablative conditioning with thiotepa, treosulfan, and fludarabine from a matched sibling donor. The second child had rejected his first graft following a busulfan‐based regimen with resultant autologous reconstitution. At 6 months post‐HSCT, serum IgG were normal, off IVIG, and had no infections. Both children after a median follow‐up of 20 months have 100% chimerism. Treosulfan‐based reduced toxicity myeloablative HSCT has encouraging results with a positive impact on the socioeconomics in developing countries.
Premature Deaths, Statistical Lives, and Years of Life Lost: Identification, Quantification, and Valuation of Mortality Risks
Authors: Hammitt James K. , Morfeld Peter , Tuomisto Jouni T. , Erren Thomas C.
Published: December 2019

Mortality effects of exposure to air pollution and other environmental hazards are often described by the estimated number of “premature” or “attributable” deaths and the economic value of a reduction in exposure as the product of an estimate of “statistical lives saved” and a “value per statistical life.” These terms can be misleading because the number of deaths advanced by exposure cannot be determined from mortality data alone, whether from epidemiology or randomized trials (it is not statistically identified). The fraction of deaths “attributed” to exposure is conventionally derived as the hazard fraction (R – 1)/R, where R is the relative risk of mortality between high and low exposure levels. The fraction of deaths advanced by exposure (the “etiologic” fraction) can be substantially larger or smaller: it can be as large as one and as small as 1/e (≈0.37) times the hazard fraction (if the association is causal and zero otherwise). Recent literature reveals misunderstanding about these concepts. Total life years lost in a population due to exposure can be estimated but cannot be disaggregated by age or cause of death. Economic valuation of a change in exposure‐related mortality risk to a population is not affected by inability to know the fraction of deaths that are etiologic. When individuals facing larger or smaller changes in mortality risk cannot be identified, the mean change in population hazard is sufficient for valuation; otherwise, the economic value can depend on the distribution of risk reductions.
Association between soft drink consumption, gastric reflux, dental erosion, and obesity among special care children
Authors: Basha Sakeenabi , Enan Enas Tawfik , Mohamed Roshan Noor , Ashour Amal Adnan , Alzahrani Fatma Salem , Almutairi Nada Eid
Published: December 2019

Objectives

This study assessed the association between soft drink consumption, gastric reflux, dental erosion, and obesity among special care children.

Materials and methods

A total of 350 special care children (male‐131, female‐219) mean age of 12.6 (± 2.6) years were included. Detection of dental erosion was performed according to the World Health Organization criteria. The medical evaluation assessed body mass index (BMI). With appropriate sample weighting, relationships between dental erosion prevalence and obesity were assessed using multivariable logistic regression.

Results

Overall prevalence of dental erosion was 36%. Mean BMI for entire study population was 24.7 (± 7.8). Regression analysis showed strong association between dental erosion prevalence and consumption of soft drinks (adjusted odds ratio = 1.8; 95% CI = 0.71‐2.92, P < .05), bulimia (adjusted odds ratio = 2.27; 95% CI = 0.99‐4.28, P < .001), and gastric reflux (adjusted odds ratio = 2.24; 95% CI = 0.82‐4.1, P < .001). Bivariate analysis showed high prevalence of dental erosion among obese children compared to children with normal weight (P = .04).

Conclusion

The present study demonstrated a significant association between dental erosion prevalence and consumption of soft drinks and gastric reflux among special care children.
Assessing depressive symptoms with the Borg centiMax Scale® in a Swedish sample of patients and students
Authors: Borg Elisabet , Jonsson Frida , Mörtberg Ewa
Published: December 2019

The Borg centiMax Scale, is a psychophysically composed general intensity ratio scale, which could enable more precise inter‐ and intraindividual comparisons of the intensity of depressive symptoms. In the present study, the properties of the centiMax scale were examined in 38 patients with clinical depression and 109 students. Additionally, preliminary centiMax cut‐off scores for mild, moderate and severe depression were estimated. The psychometric properties of the centiMax were found to be satisfactory regarding internal consistency, convergent, discriminative and predictive validity. Moreover, the centiMax was demonstrated to provide meaningful comparisons of symptom intensity, which makes it possible to evaluate the relative importance of individual symptoms in a profile and make more precise comparisons within and between individuals. With regard to intraindividual comparisons, patients rated , for example, the intensity of feeling “guilt” twice as strong as feelings of “being punished,” and the intensity of “loss of pleasure” almost three times as strong as “being punished.” With regard to interindividual comparisons, patients rated e.g., the intensity of “being punished” as 12 times stronger than controls, and the intensity of “worthlessness” about nine times stronger. In conclusion, the centiMax was shown to be reliable and valid for assessing depressive symptoms. The centiMax with level anchored ratio data, appears to be highly advantageous as it permits rather precise values of symptom intensity for intra‐ and interindividual comparisons that could be useful in the diagnostic process and in treatment planning.
The screening of rare blood donors in a highly admixed population: A new approach for Holley and Diego genotyping and impact of genomic and self‐reported ancestry
Authors: Muniz Amanda A. , da Silva Adão R. , Ferraz Isabela A. , Martins Marina L. , Godin Mariana M. , Schmidt Luciana C. , Dusse Luci M. S. A. , da Silva Malta Maria Clara Fernandes
Published: December 2019

Objectives

The present study aimed to develop strategies for genotyping DO*HY (Dombrock system) and DI*A/DI*B (Diego system) alleles and to evaluate the impact of genomic and self‐declared ancestry on rare donor screening in admixed populations.

Background

The antigens Hy and Dib demonstrate clinical importance. The lack of antisera for the serological evaluation of these antigens makes it necessary to develop molecular methods. In addition, considering that some rare red blood cell phenotypes present differences in frequency between ethnic groups, it is important to assess the applicability of self‐declared ancestry in the search for rare donors in admixed populations.

Methods

DO*HY and DI*A/DI*B genotyping based on real‐time polymerase chain reaction (PCR) was standardised. A total of 457 blood donors clustered by self‐defined skin colour/race categories were genotyped. Furthermore, individual genomic ancestry was used in the analyses.

Results

The assays developed are reproducible and provide satisfactory results even at low concentrations of DNA, which make them useful in situations where the DNA is scarce, such as dried blood spots on filter paper, or when screening for pooled samples. No significant difference was observed in the frequencies of the DI*A, DI*B and DO*HY, comparing the self‐declared White (branco) donors with those who are Black (preto) and Brown (pardo).

Conclusion

Real‐time PCR, especially using pooled samples, is a promising strategy to screen rare blood donors. Although both self‐reported race/colour and some blood group phenotypes are associated with ancestry, the results point to a greater complexity in the application of self‐declared race/colour in the screening of rare donors in admixed populations.
Analytical validation of an enzyme‐linked immunosorbent assay for the quantification of S100A12 in the serum and feces of cats
Authors: Bridges Cory S. , Grützner Niels , Suchodolski Jan S. , Steiner Jörg M. , Heilmann Romy M.
Published: December 2019

Background

Measuring S100A12 concentrations in serum and feces is a sensitive and specific marker of inflammation, such as seen with chronic gastrointestinal inflammation in people and dogs. Biomarkers of inflammation in cats are currently lacking.

Objectives

We aimed to analytically cross‐validate the canine S100A12‐ELISA for the measurement of S100A12 in feline specimens.

Methods

The ELISA was analytically validated by assessing dilutional linearity, spiking/recovery, intra‐ and inter‐assay variability. Reference intervals for serum and fecal feline S100A12 concentrations were calculated using samples from healthy cats, and the short‐term biological variation of fecal S100A12 was assessed.

Results

Observed‐to‐expected ratios (O/E) for serial dilutions of serum and fecal extracts ranged from 91%‐159% (mean, 120%) and 100%‐128% (mean, 114%), and for the spiking/recovery method ranged from 106%‐263% (mean, 154%) and 52%‐171% (mean, 112%). Intra‐ and inter‐assay CV% for serum were ≤5.6% and ≤14.0%, and for fecal extracts were ≤3.8% and ≤19.1%, repsectively. RIs for feline serum and fecal S100A12 concentrations were <43 µg/L and < 20 ng/g, respectively. A mild short‐term biologic variation, but large individuality were detected when measuring fecal S100A12 concentrations in healthy cats.

Conclusions

The canine S100A12‐ELISA is accurate, reproducible, and sufficiently linear and precise for the measurement of S100A12 in feline serum and fecal samples. The use of this assay is a reasonable option for the measurement of S100A12 concentrations in feline specimens and provides a basis for the further evaluation of  S100A12 in cats with gastrointestinal disease. Using a population‐based RI for fecal feline S100A12 appears to be of limited value.
Novel sexual dimorphism in a new genus of Bathynellidae from Russia, with a revision of phylogenetic relationships
Authors: Camacho Ana I. , Mas‐Peinado Paloma , Iepure Sanda , Perina Giulia , Dorda Beatriz A. , Casado Adrian , Rey Isabel
Published: December 2019

Bathynellidae is the neglected family of Bathynellacea, a groundwater group of crustaceans with 33 genera and 107 species described and almost half of them included in the ‘catch‐all’ genus Bathynella. Due to the morphological homogeneity of the species, the taxonomic uncertainties have accumulated over time. Therefore, to explore the phylogenetic relationships among taxa, a combined approach using morphological and molecular data is needed. In this paper, we performed a phylogenetic analysis based on partial sequences of COI and 18S including 30 species of Bathynellidae. This data set represents the most updated one, including a new genus and a new species (Altainella calcarata gen. n. sp. n.) of Bathynellidae described here from Altai Mountain (Russia). The new taxon presents a new type of sexual dimorphisms with a peculiar structure on the coxopod of the male thoracopod VII and also sexual dimorphism on the mandibular palp, as some species of the subfamily Gallobathynellinae. This is the first species of Bathynellidae that presents both variants of sexual dimorphism. The molecular phylogeny supports the morphology and the erection of the new genus and displays highly divergent genetic units corresponding to subfamilies, with the new genus closer to Bathynellinae genera than other subfamilies. With the description of this new species and its molecular characterization, the existence of the other genera beyond Bathynella is confirmed in Eurasia.
Molecular and morphometric analyses identify new lineages within a large Eumida (Annelida) species complex
Authors: Teixeira Marcos A. L. , Vieira Pedro E. , Pleijel Fredrik , Sampieri Bruno R. , Ravara Ascensão , Costa Filipe O. , Nygren Arne
Published: December 2019

We report on two new lineages of the Eumida sanguinea complex from Great Britain and describe one of them as a new species using a multilocus approach, including the mitochondrial DNA COI‐5P and the nuclear markers ITS (ITS1, 5.8S rRNA and ITS2) and 28S rRNA. The molecular analysis placed Eumida mackiei sp. nov. in a monophyletic clade with 19.1% (COI), 10.1% (ITS) and 1.7% (28S) mean distance to its nearest neighbour. Molecular diagnoses were also applied to nine lineages within the E. sanguinea complex. This was complemented with morphometric data employing multivariate statistical analysis and the incorporation of statistical dissimilarities against three other described species from the complex. Eumida mackiei sp. nov. can be distinguished from E. notata and E. maia by the larger distance between the eyes and differences in morphometric proportions mainly in the dorsal and ventral cirri as well as in the prostomial appendages. E. sanguinea sensu stricto failed to produce a cluster of its own in the morphometric analysis, probably due to juvenile bias. Integrative taxonomy provided strong evidence to formally describe a new cryptic species that can now be used in biomonitoring or other relevant ecological research.
Dermatomiositis como expresión de síndrome paraneoplásico
Authors: Mejía-López María Gimena , Alvarado-Ospina Yury Alejandra , Gutiérrez Juan Martín , Fernández-Ávila Daniel G. , Díaz María Claudia
Published: December 2019

La dermatomiositis es una miopatía inflamatoria con afectación cutánea que se ha encontrado asociada con procesos neoplásicos. El artículo presenta el caso de una paciente de 74 años de edad, quien posterior al diagnóstico de dermatomiositis consultó por síntomas de disfagia, asociada con una significativa pérdida de peso. Dadas descripciones previas de la relación de dermatomiositis con cáncer, se decidió iniciar búsqueda de malignidad asociada y se encontró un proceso neoplásico avanzado, con causa primaria desconocida, que requirió manejo paliativo. Por la mayor incidencia de malignidad en pacientes con dermatomiositis, comparada con la población general, es de vital importancia atender a los signos descritos como predictores de la asociación y no pensar en estas como entidades aisladas.
Frecuencia de complicaciones sépticas posterior a cistouretrografía miccional sin urocultivo de control previo en niños de tres meses a nueve años de edad con infección de vías urinarias y respuesta clínica a antibioticoterapia adecuada
Authors: Mejía Pavony Juan Gonzalo , Bustos Sánchez Diana Carolina , Rey Camacho Sandra Janeth , Vásquez Blanco Gladys Johanna , Lozano Juan Manuel
Published: December 2019

Con el ánimo de medir la frecuencia de complicaciones sépticas secundarias a la elaboración de la cistouretrografía miccional sin urocultivo de control en niños de tres meses a nueve años de edad con infección urinaria tratados en el Hospital San Ignacio y que tuvieron respuesta clínica adecuada al antibiótico, se diseñó un estudio de cohortes retrospectivo de dos años. Se revisaron un total de 243 historias, cuyos datos fueron extraídos con base en el formulario de recoleccion de datos. Ninguno de los 59 pacientes que cumplían los criterios de inclusión presentaron complicaciones sépticas. Se propone elaborar un estudio longitudinal prospectivo que pretenda demostrar la concordancia del criterio clínico de curación de la infección urinaria correspondiente a 48 horas sin fiebre luego del inicio del tratamiento, con el urocultivo negativo necesario, propuesto en las guías actuales, para evitar su solicitud con el objeto de minimizar costos de salud y tiempos y oportunidad de atención.
Neutropenia febril y pancitopenia aguda en pacientes con leucemia linfoide aguda posterior a consolidación con metotrexato en el Centro Javeriano de Oncología durante el periodo 2012-2014
Authors: Córdoba Núñez María Adelaida , Guzmán Cruz Paula Carolina , Acero Azuero Silvia
Published: December 2019

Introducción: La leucemia linfoide aguda (LLA) es la neoplasia infantil más frecuente. Su tratamiento incluye 3 fases, una de las cuales es la consolidación, donde el pilar fundamental es el uso de metotrexato a dosis diferenciales, dependiendo de la clasificación de riesgo de la enfermedad.Objetivo: Estimar la presencia de neutropenia febril, anemia y trombocitopenia en pacientes con LLA que recibieron durante la consolidación metotrexato a dosis de 5 g/m2 respecto a los pacientes que recibieron dosis de 2 g/m2.Métodos: Se revisaron todas las historias clínicas de los pacientes de 1 a 15 años de edad con LLA atendidos en el Centro Javeriano de Oncología, desde el 1 de enero del 2012 hasta el 10 de marzo del 2014. Resultados: Se recolectó información de 66 ciclos de quimioterapia, de los cuales 31 correspondían a aplicaciones de 2 g/m2 y 35 a aplicaciones de 5 g/m2. La frecuencia de neutropenia febril en el grupo de 2 g/ m2 fue del 25 % y del 34 % en el grupo de 5 g/m2, lo que se asemeja a lo reportado en la literatura.Conclusión: El uso de metotrexato a altas dosis para el manejo de LLA en nuestro medio no aumentó la toxicidad hematológica con respecto al grupo de dosis baja. Y hay evidencia suficiente de mejoría en las tasas de curación de la enfermedad.
A Three-Dimensional Coupled Finite Element Model for the Simulation of Stress Corrosion on Pipeline Steel
Authors: Sun Dongxu , Wu Ming , Xie Fei , Gong Ke
Published: December 2019

In this study, a three-dimensional finite element model was constructed to study the stress corrosion behavior of pipeline steel. Stress analysis and electrochemical calculation were incorporated into the model through multiphysics field coupling technique. Tensile property and electrochemical corrosion behavior of X70 pipeline steel were measured by experiments to formulate the model. The modeling results show that the corrosion is accelerated on the surface of corrosion defect where the stress tends to concentrate because of mechanoelectrochemical effect. The effect of elastic strain on corrosion enhancement is not obvious. The plastic deformation on defect bottom increases the corrosion rate significantly, especially for the conditions with high operating pressure or large defect depth. The corrosion current distribution indicated that the “self-acceleration effect” exists on corrosion defect. This effect makes the corrosion develop to depth and the shape of corrosion defects is more likely to cause stress concentration, and finally induces corrosion perforation or cracking. The two directions, i.e. axial and circumferential direction, have the different stress corrosion behaviors. The “self-acceleration effect” is more obvious on circumferential direction than that on axial direction, which can explain the phenomenon that there are mostly axial stress corrosion cracks on the pipeline in field.
A Study on Energy Saving Potential of the Ground System in Oil Field Considering the Light Hydrocarbon Component
Authors: Yingze Tong , Gang Liu , Lei Chen
Published: December 2019

The dissolution of light components in crude oil would increase its saturated vapor pressure, and easy to produce losses during the storage and transportation process. However, the crude oil containing light hydrocarbons has better flowing properties and rheological properties under low temperature. Compared with degassed crude oil, the viscosity, yield stress and freezing point of dissolved-gas crude oil have been improved obviously. On the basis of analyzing energy consumption of the gathering system and total energy cost of pipeline operation, the improved gathering and transportation process without the device in stabilizing crude oil will be considered. The new process mode not only makes the overall upstream of the gathering and transportation system be airtight, but also has the advantages of simple process, less equipment, high degree of automation and convenient management. It helps to form an integrated three-links structure among joint station, pipeline and refinery, which is of a huge energy-saving potential to the environment and safe operation of the gathering and transportation system with crude oil pipelines.
Investigation on Corrosion Base Characteristics and Deep Dehydration Technology of Micro-Droplets in Oil Pipelines
Authors: Guo Kai , Lv Yuling , He Limin , Luo Xiaoming , Yang Donghai
Published: December 2019

Corrosion is an important cause of steel pipeline failure and oil leakage, especially local pitting corrosion in long distance crude oil pipelines. Deep dehydration is of great significance to pipeline anticorrosion, however, further experimental results show that it is very difficult to achieve deep dehydration by a single electric field. Recent studies have shown that the particle size change of dispersed phase for the emulsion with large droplets after electromagnetic synergistic treatment is more obvious than that of a single electric field. In this study, the effect of micro-droplets on corrosion of oil pipelines are revealed. The role of micro-droplets in the process of microbial corrosion and electrochemical corrosion in a strong or weak acid solution for oil pipelines was summarized. A structural model of on-line tubular electromagnetic synergistic intensification coalescing device was established. The size change of particle of the dispersed phase in emulsions was studied. Crude oil and water were used as experimental materials, and the particle size distribution of dispersed phase in emulsions was tested by the evaluation system. The results showed that mean radius, d10 and d50 of water droplets in emulsion treated by electromagnetic synergism are larger than those treated by a single electric field. Strengthening droplets coalescence by electromagnetic synergism is also effective on emulsions whose particle size of the dispersed phase is less than 100μm. The role of micro-droplets in pitting corrosion is summarized based on corrosion channels. In the process of microbial corrosion and electrochemical corrosion in strong or weak acid solution, the role of water is presented in two aspects like participating in the reaction and providing ion electron transmission media. Analogous to culture medium, micro water droplets can be called corrosion medium for pitting corrosion in long-distance crude oil pipelines. A structural model of on-line tubular electromagnetic synergistic intensification coalescing device was established, including an electric field generation device and a magnetic field excitation component with orthogonal distribution and synchronous synergy. And emulsions are treated by electric and magnetic fields while flowing through the medium channel. The particle size change of dispersed phase in emulsions with average particle size of dispersed phase less than 100μm was experimental studied. It is found that mean radius, d10 and d50 of water droplets in emulsion treated by electromagnetic synergism are larger than that by a single electric field. Therefore, electromagnetic synergism can further enhance the dehydration depth compared with a single electric field.
Simulation and Experiment Study of Gas-Liquid Two-Phase Flow Leakage in Horizontal Pipelines
Authors: Jian Ji
Published: December 2019

The influence of flow pattern, leakage location and leakage aperture changes on the flow field and the sound field in horizontal pipelines are studied in this paper. The CFD software is used to simulate the gas-liquid two-phase flow in horizontal pipes. Findings from literature research, it is necessary to study the change of flow field with different parameters in the simulation process. To study the flow field, first, a mathematical model of gas-liquid two-phase flow pipeline leakage established. The flow field parameters of gas-liquid two-phase flow is calculated under different gas&liquid inlet. Then, the fluent is used to solve the flow field, and the appropriate acoustic model is selected to realize the conversion of flow pattern to sound field. Finally, the simulation results are analyzed and verified through experiments. In this paper, we have simulated the change characteristics of the flow field and sound field of different flow pattern, leakage position, aperture size and the sound field, which is helpful to further understand and grasp the location and propagation law of the leakage source.
Analysis of the Velocity and Shear Stress of the Local Water-Diesel Flow System
Authors: Xu Guangli , Liu Tong , Niu Zhenyu , Cai Liangxue , Wang Menglong
Published: December 2019

The operation of pipelines has been affected by the corrosion caused by water deposited in some low sections of liquid products and natural gas pipeline. Flushing out the deposited water by flowing diesel has become a popular method. This research focused on a local water-diesel flow system with low Uos, in which the flow pattern, velocity and shear stress were analyzed through 2D simulation conducted by FLUENT software based on the grid independent strategy; meanwhile the simulations were verified by comparison with the published data.

Under the shear from flowing diesel with laminar flow, the flow pattern was found mainly as smooth and wavy stratified flow. The velocity of diesel phase becomes similar-parabolic distribution with an offset upwards in the radical direction, while there are reflux and eddy inside the residual water. Because of the presence of residual water, the shear stress of the walls become negative, and it increases along the two walls to the interface radically and increases to the maximum on the interface. The average velocity of residual water was found to increase linearly with the superficial velocity of oil flow.
Characterization of a Water-in-Waxy Crude Oil Emulsion by its Steady Apparent Viscosity
Authors: Guo Liping , Feng Tao , Liu Yang , Chen Xu , Li Wenbo , Hsu Jyh-Ping
Published: December 2019

The rheological properties of water-in-waxy crude oil emulsion depend highly on its forming conditions. Among these, the steady apparent viscosity is capable of characterizing its degree of emulsification. Adopting waxy crude oil in the field, we examine the influence of the water cut, the stirring speed, and the stirring time on the steady apparent viscosity of the emulsions formed under various conditions in this study. A model based on the viscous flow entropy generated in emulsion preparation is applied to correlate the steady apparent viscosity with the key parameters. A regression model is constructed for the dependence of the steady apparent viscosity on the viscous flow entropy, the shear rate, the rheological parameters of blank crude oil, and the wax deposition volume.
Influence of Inertia Terms on High Pressure Gap Flow Applications in Hydraulics
Authors: Fischer Felix , Rhein Andreas , Schmitz Katharina
Published: December 2019

Hydraulic pumps, which reach pressures up to 3000 bar, are often realized as plunger-piston type pumps. In the case of a common-rail pump for diesel injection systems, the plunger is driven by a cam-tappet construction and the contact during suction stroke is maintained by a helical spring. Many hydraulic piston-based high pressure pumps include gap seals, which are formed by small clearances between the two surfaces of the piston and the bushing. Usually the gap height is in the magnitude of several micrometers. Typical radial gaps are between 0.5 and 1 per mil of the nominal diameter. These gap seals are used to allow and maintain pressure build up in the piston chamber.

When the gap is pressurized, a special flow regime is reached. For the description of this particular flow the Reynolds equation, which is a simplification of the Navier-Stokes equations, can be used as done in the state of the art. Furthermore, if the pressure in the gap is high enough — 500 bar and above — fluid-structure interactions must be taken into account. Pressure levels above 1500 or 2000 bar indicate the necessity for solving the energy equation of the fluid phase and the rigid bodies surrounding it.

In any case, the fluid properties such as density and viscosity, have to be modelled in a pressure dependent manner. This means, a compressible flow is described in the sealing gap. Viscosity changes in magnitudes while density remains in the same magnitude, but nevertheless changes about 30 %. These facts must be taken into account when solving the Reynolds equation.

In this paper the authors work out that the Reynolds equation is not suitable for every piston-bushing gap seal in hydraulic applications. It will be shown that remarkable errors are made, when the inertia terms in the Navier-Stokes equations are neglected, especially in high pressure applications.

To work out the influence of the inertia terms in these flows, two simulation models are built up and calculated for the physical problem. One calculates the compressible Reynolds equation neglecting the fluid inertia. The other model, taking the fluid inertia into account, calculates the coupled Navier-Stokes equations on the same geometrical boundaries. Here, the so called SIMPLE (Semi-Implicit Method for Pressure Linked Equations) algorithm is used. The discretization is realized with the Finite Volume Method. Afterwards, the solutions of both models are compared to investigate the influence of the inertia terms on the flow in these specific high pressure applications.
Monitoring Digital Technologies in Hydraulic Systems Using CUSUM Control Charts
Authors: Breidi Farid , Chehade Abdallah , Lumkes John
Published: December 2019

Digital fluid power is a growing field which utilizes electronics and advanced controls to improve efficiencies, energy savings, and productivity in fluid power systems. Often relying on on/off high-speed switching techniques, digital hydraulics relies heavily on the performance of valves, where an error in the valve performance could lead to a major drop in the efficiency and performance of the entire system. Specifically, digital pump/motors are sensitive to valve delay and transition timing which negatively impacts their performance and condition with time. One approach to assessing the performance and efficiency of digital pump/motors is via monitoring its inlet (low) and outlet (high) pressure time-series. Real-time condition monitoring also supports preventive maintenance and provides a better understanding of the dynamics of pump/motors. For condition monitoring, Statistical Process Control (SPC) charts are often designed to detect shift changes in time-series. This paper proposes to construct two cumulative sum (CUSUM) control charts for fast real-time shift detection in the high and low pressure time-series of digital pump/motors. The proposed method will be able to actively detect common misbehaviors in the valves utilized in the digital pump/motor. The model have been successfully tested on a three-piston inline digital pump/motor, but this monitoring technique can be modified and implemented on other digital technology classes where valve performance is key in the success of the system.
Bio-Based Hydraulic Fluids in Mobile Machines: Substitution Potential in Construction Projects
Authors: Deuster Sebastian , Schmitz Katharina
Published: December 2019

This paper deals with the hydraulic oil consumption of mobile working machines. Different mobile working machines are going to be investigated by setting out their hydraulic oil consumption per hour. The substitutable amount of mineral by bio-based hydraulic oil is examined by an exemplary calculation for a construction project. The observations are intended to establish the working medium bio-based hydraulic oil on the lubricants market and to increase its use quantities, especially for mobile machines, with regard to environmental protection. Environmentally friendly lubricants and process materials are used in a wide variety of technical applications. In mobile machines in particular, efforts are being made to further establish bio-based lubricants. Due to unforeseeable accidents and leaks, a considerable amount of lubricants is released into the environment every year. This results in contamination of the affected environment. For this reason, contaminated ground, for example, has to be excavated refurbished after contact with hydraulic oil in order to return them to their original natural state. Bio-based hydraulic oils minimize this risk through their biodegradability and antitoxicity. Despite the proven performance of environmentally friendly hydraulic oil, the market share of biolubricants is stagnating at a constant and very low level. The majority of mobile machines use mineral oil, as working fluid in their hydraulic systems. To evaluate the substitution potential of mineral oil by bio-based oil in construction projects, various mobile machines are considered. In addition to widely used mobile machines like, for example excavators or wheel loaders, road construction equipment is also considered, due to a high hydraulic oil consumption resulting through heavy heat loads.
Modeling, Validation, and Investigation of an Electrohydraulic Crimping Hand Tool
Authors: Norquist Eric D. , Slightam Jonathon E. , Nagurka Mark L.
Published: December 2019

Due to their high power density, hydraulic systems are increasingly adapted for human scale devices. For example, commercial and utility electricians use electrohydraulic cutting and crimping tools, rather than human powered tools, to cut and crimp wires that exceed 25mm in diameter. These tools greatly reduce worker-related fatigue and strain-type injuries. To improve electrohydraulic tool technology, there is a need to increase the number of applications from a single battery charge. This paper develops a high fidelity nonlinear lumped parameter model of an electrohydraulic crimping hand tool used by professional electricians. The eleventh-order model can predict tool performance with an average error of 6.9% and 4.4% with respect to the maximum energy consumption and crimp time, respectively. Simulation studies were conducted to investigate reducing the energy consumption of the tool. An independent parameter sweep was performed on the pump piston diameter. The gear ratio was a dependent parameter linked through the maximum motor torque. Increasing the pump piston diameter while increasing the gear ratio was shown to decrease the energy consumption of the tool during crimping applications. Simulations suggest that up to 30% energy can be saved per crimp by increasing the pump piston diameter and gear train ratio.
Parameter Identification for Model-Based Control of Hydraulically Actuated Open-Chain Manipulators
Authors: Hulttinen Lionel , Koivumäki Janne , Mattila Jouni
Published: December 2019

In this paper, a nonlinear model-based controller with parameter identification is designed for a rigid open-chain manipulator arm actuated by servovalve-controlled hydraulic cylinders. The arising problem in adopting model-based controllers is how to acquire accurate estimates of system parameters, with limited available information about either the hydraulic actuator parameters or manipulator link inertial parameters. The objective of this study is to identify both the rigid-body parameters of the links and the hydraulic actuator parameters from collected cylinder chamber pressure and joint angle data, while no a priori knowledge of these parameters is available. Same physical plant models are used for control design as well as for parameter identification. Experimental results show that the proposed nonlinear model-based control scheme results in acceptable Cartesian position tracking performance in free-space motion when using the identified parameters.
Investigating Fault Detection and Diagnosis in a Hydraulic Pitch System Using a State Augmented EKF-Approach
Authors: Asmussen Magnus F. , Pedersen Henrik C. , Lilleengen Lina , Larsen Andreas , Farsakoglou Thomas
Published: December 2019

Pitch systems impose an important part of today’s wind turbines, where they are both used for power regulation and serve as part of a turbines safety system. Any failure on a pitch system is therefore equal to an increase in downtime of the turbine and should hence be avoided. By implementing a Fault Detection and Diagnosis (FDD) scheme faults may be detected and estimated before resulting in a failure, thus increasing the availability and aiding in the maintenance of the wind turbine. The focus of this paper is therefore on the development of a FDD algorithm to detect leakage and sensor faults in a fluid power pitch system.

The FDD algorithm is based on a State Augmented Extended Kalman Filter (SAEKF) and a bank of observers, which is designed utilizing an experimentally validated model of a pitch system. The SAEKF is designed to detect and estimate both internal and external leakage faults, while also estimating the unknown external load on the system, and the bank of observers to detect sensor drop-outs. From simulation it is found that the SAEKF may detect both abrupt and evolving internal and external leakages, while being robust towards noise and variation in system parameters. Similar it is found that the scheme is able to detect sensor drop-outs, but is less robust towards this.
Improving the Efficiency and Dynamic Properties of a Flow Control Unit in a Self-Locking Compact Electro-Hydraulic Cylinder Drive
Authors: Schmidt Lasse , Ketelsen Søren , Padovani Damiano , Mortensen Kasper Aa.
Published: December 2019

The introduction of low cost electric motor and drive solutions provides the possibility to design cost competitive compact speed-variable drives as potentially feasible alternatives to conventional valve-controlled solutions. A main drawback in existing self-contained drive technology is the power consumption in stationary load carrying situations. However, the recent introduction of compact self-locking drive topologies with separate forward and return flow lines allow to significantly minimize the power consumption, but introduces another problem. Dependent on the control of the flow device, a continuous, but lower power consumption compared to non-self-locking drive topologies may be present. Furthermore, the piston motion may exhibit a time delay due to an outlet pressure build-up phase in the flow unit prior to actuation of the cylinder, limiting the application range of such a drive concept. The purpose of the study presented, is to analyze these properties through model-based methods, and to establish control functionalities allowing to minimize these unfortunate features. The resulting flow device control structure allows for a significant reduction in the actuation time delay as well as in the power consumption in stationary load carrying situations. Numerical results demonstrate the properties announced by the theoretical analysis and control design phase, hence broadening the application range of the self-locking drive topology in question.
Concept Studies on a Multifunctional Unit for Hydraulic Supply and High Lift Actuation in Aircraft
Authors: Nordmann Lennard , Thielecke Frank , Lücken Peter , Hamm Martin
Published: December 2019

This paper investigates the potential of a new functionality of the hybrid Power Control Unit (PCU) in zonal electrohydraulic aircraft systems. The conventional PCU, as a hydraulic consumer, is the central drive for the leading and trailing edge flaps of an aircraft. Through extended functionality, it can also be operated as pump to provide hydraulic power in certain flight phases. The paper elaborates and presents different concepts for the integration of such a multifunctional PCU and evaluates the potential regarding mass savings and improvement of reliability. In subsequent simulation studies, the most promising concept is validated and analysed regarding the arising challenges.