bluuebunny/crossref_metadata_2025 huggingface dataset:
Client‐Related Factors Associated with a “Less than Good” Experience of Midwifery Care during Childbirth in the Netherlands
Authors: Baas Carien I. , Wiegers Therese A. , de Cock T. Paul , Erwich Jan Jaap H. M. , Spelten Evelien R. , de Boer Michiel R. , Hutton Eileen K.
Published: December 2016

Background

A “less than good” experience during childbirth can affect a mother's early interaction with her child and may significantly influence a woman's emotional well‐being. In this study, we focus on clients who experienced midwifery care provided during childbirth as “less than good” care. The aim of this study was to understand the relationship between client‐related factors and the experience of midwifery care during childbirth to improve this care.

Methods

This study was part of the “DELIVER study” where mothers report on the care they received. We used generalized estimation equations to control for correlations within midwife practices. Forward multivariate logistic regression analyses were conducted to model the client‐related factors associated with the experienced midwifery care during childbirth.

Results

We included the responses of 2,377 women. In the multivariable logistic regression model, odds of reporting “less than good care” were significantly higher for women who experienced an unplanned cesarean birth (OR 2.21 [CI 1.19–4.09]), an instrumental birth (OR 1.55 [CI 1.08–2.23]), and less control during the dilation phase (OR 0.98 [CI 0.97–0.99]) and pushing phase (OR 0.98 [CI 0.97–0.99]).

Discussion

Birth‐related factors were more likely than maternal characteristics to be associated with the experience of midwifery care during childbirth. We conclude that there is room for midwives to improve their care for women during childbirth particularly in improving the patient centeredness of the care provider, using strategies to enhance sense of control, and focusing on the particular needs of those who experience instrumental vaginal or unplanned cesarean births.
Feedback methods for student voice in the digital age
Authors: Zou Di , Lambert James
Published: December 2016

Central to the concept of Student Voice is the communication of student feedback to educators. Feedback can assume a great variety of forms, and effectiveness and appropriacy of different feedback methods may vary. This research investigates student perceptions of two traditional feedback methods—pen‐and‐paper questionnaires and oral question‐and‐answer reports—compared against feedback obtained through the use of three digital technology tools (Socrative, TodaysMeet and Google Drive). The findings suggest that the use of digital technologies in Student Voice contexts is likely to be highly effective due to the overwhelming positive attitude of students towards these tools.
Instructor and adult learner perceptions of the use of Internet‐enabled devices in residential outdoor education programs
Authors: Bolliger Doris U. , Shepherd Craig E.
Published: December 2016

As more adults frequent wilderness areas, they bring Internet‐enabled devices (e.g., smart phones, tablets) with them. This study focuses on adults' perceptions of these devices in relation to desired outdoor learning experiences. Specifically, researchers examined the perspectives of naturalists who taught outdoor education programs and park visitors who participated in these programs. Using interviews and surveys to consider experiences, researchers found that participants enjoyed instructional Internet use to reduce physical dependence on heavy resources, support learning, engage younger learners and communicate with others. However, clear boundaries were identified regarding when and where these technologies could be used in national park settings.
The effectiveness of digital game‐based vocabulary learning: A framework‐based view of meta‐analysis
Authors: Chen Meng‐Hua , Tseng Wen‐Ta , Hsiao Tsung‐Yuan
Published: December 2016

This study presents the results of a meta‐analytic study about the effects of digital game‐based learning (DGBL) on vocabulary. The results of the study showed that the effects of DGBL on vocabulary learning may vary with game design features (Q = 5.857, df = 1, p = .016), but not with learners' age (Q = 0.906, df = 1, p = .341) or linguistic background (Q = 0.0001, df = 1, p = .994). In light of the research findings, Csikszentmihalyi's () Flow Theory was adopted to theorize the role of game design in DGBL. It is proposed that a hierarchy should exist on the “challenge” axis in the Flow Theory, with adventure‐oriented games above non‐adventure‐based games along the “challenge” axis. The theoretical underpinning is that the dynamic equilibrium between challenge and abilities can function independently of the effects of learners' age and linguistic background.
Maternal genetic polymorphisms and unexplained recurrent miscarriage: a systematic review and meta‐analysis
Authors: Shi X. , Xie X. , Jia Y. , Li S.
Published: December 2016

The roles of genetic polymorphisms in the pathogenesis of recurrent miscarriage (RM) have been intensively studied. However, the results of these studies were inconsistent, especially when conducted in different populations. Therefore, we performed the current study to systematically review the broad spectrum of genetic polymorphisms that were suspected to be involved in RM, and discussed potential genetic biomarkers of RM. Eligible articles were identified in PubMed, Medline, Embase and CNKI. Odd ratios (ORs) and 95% confidence intervals (CIs) were used to describe the strength of association, and a probability value (p value) of 0.05 or less was considered as statistically significant. A total of 425 eligible articles were included in this systematic review and 369 articles evaluating 124 polymorphisms of 73 genes were meta‐analyzed. Significant associations were found between RM and 53 genetic polymorphisms of 37 genes. Our findings suggest that genetic variants of HLA‐G, IFNG, TNF, IL‐6, IL‐10, FII, FV, FXIII, ITGB3, MTR, MTHFR, PAI‐1, NOS3, KDR, TP53, VEGFA, CYP17, CYP1A1, CYP2D6, ANXA5, and XCI may serve as biological markers of RM. This study indicates that over‐active immunological responses, thrombophilia, abnormal placental function, and disturbance of metabolic regulation may be implicated in the pathogenesis of RM.
Induced pluripotent stem cells as a new getaway for bone tissue engineering: A systematic review
Authors: Bastami Farshid , Nazeman Pantea , Moslemi Hamidreza , Rezai Rad Maryam , Sharifi Kazem , Khojasteh Arash
Published: December 2016

Objectives

Mesenchymal stem cells (MSCs) are frequently used for bone regeneration, however, they are limited in quantity. Moreover, their proliferation and differentiation capabilities reduce during cell culture expansion. Potential application of induced pluripotent stem cells (iPSCs) has been reported as a promising alternative source for bone regeneration. This study aimed to systematically review the available literature on osteogenic potential of iPSCs and to discuss methods applied to enhance their osteogenic potential.

Methods and materials

A thorough search of MEDLINE database was performed from January 2006 to September 2016, limited to English‐language articles. All in vitro and in vivo studies on application of iPSCs in bone regeneration were included.

Results

The current review is organized according to the PRISMA statement. Studies were categorized according to three different approaches used for osteo‐induction of iPSCs. Data are summarized and reported according to the following variables: types of study, cell sources used for iPSC generation, applied reprogramming methods, applied osteo‐induction methods and treatment groups.

Conclusion

According to the articles reviewed, osteo‐induced iPSCs revealed osteogenic capability equal to or superior than MSCs; cell sources do not significantly affect osteogenic potential of iPSCs; addition of resveratrol to the osteogenic medium (OM) and irradiatiation after osteogenic induction reduce teratoma formation in animal models; transfection with lentiviral bone morphogenetic protein 2 results in higher mineralization compared to osteo‐induction in OM; addition of TGF‐β, IGF‐1 and FGF‐β to OM increases osteogenic capability of iPSCs.
Hybrid Speech Acts: A Theory of Normative Thought and Language That ‘Has It Both Ways’
Authors: Morgan Andrew
Published: December 2016

In this essay, I propose a novel hybrid metanormative theory. According to this theory, speakers making normative claims express both cognitive and motivational attitudes in virtue of the constitutive norms of the particular speech acts they perform. This view has four principal virtues: (1) it is consistent with traditional semantic theories, (2) it supports a form of motivational judgment internalism that does justice to externalist intuitions, (3) it illuminates the connection between normative language and normative thought, and (4) it explains how speakers can express different conative states when speaking in different normative domains. In the first section, I discuss the theories of Stephen Finlay and David Copp. I show that they each come very close to having it both ways but ultimately fail. Understanding the shortcomings of these views is instrumental to a clear presentation of my own Hybrid Speech Act theory in section two. In the final section, I demonstrate how my view achieves its four advantages.
Theorising from the Global Standpoint: Kant and Grotius on Original Common Possession of the Earth
Authors: Huber Jakob
Published: December 2016

The paper contrasts Kant's conception of original common possession of the earth with Hugo Grotius's superficially similar notion. The aim is not only to elucidate how much Kant departs from his natural law predecessors—given that Grotius's needs‐based framework very much lines in with contemporary theorists’ tendency to reduce issues of global concern to questions of how to divide the world up, it also seeks to advocate Kant's global thinking as an alternative for current debates. Crucially, it is Kant's radical shift in perspective—from an Archimedean ’view from nowhere‘, to a first‐personal standpoint through which agents reflexively recognise their systematic interdependence in a world of limited space—that provides him with the more thorough and ultimately convincing global standpoint. This standpoint does not come with ready‐made solutions to shared global problems, but provides a promising perspective from which to theorise them.
Realism, Utopianism, and Radical Values
Authors: Raekstad Paul
Published: December 2016

One of the more debated topics in the recent realist literature concerns the compatibility of realism and utopianism. Perhaps the greatest challenge to utopian political thought comes from Bernard Williams' realism, which argues, among other things, that political values should be subject to what he calls the ‘realism constraint’, which rules out utopian arguments based on values which cannot be offered by the state as unrealistic and therefore inadmissible. This article challenges that conclusion in two ways. First, it argues that the rationale for accepting Williams' original argument for the ‘realism constraint’ fails. Secondly, it argues that there is at least one genuinely political value of liberty available which is both compatible with realism and something that cannot be offered by the state, namely that of the political anarchist. This opens the way for far more ambitious and utopian forms of realist political thought and implies that the arguments of what we call political anarchists must be met by (realist) political argumentation, not simply ruled out by methodological stipulation.
Spectral electroencephalography profile of rapid eye movement sleep at sleep onset in narcolepsy type 1
Authors: Pizza F. , Ferri R. , Vandi S. , Rundo F. , Iloti M. , Neccia G. , Plazzi G.
Published: December 2016

Background and purpose

The sleep‐onset rapid eye movement (REM) period (SOREMP), the hallmark of narcolepsy, may be a specific state and not the simple anticipation of REM sleep.

Methods

We analyzed the electroencephalographic spectral content in untreated patients with narcolepsy type 1 (NT1) during the sleep‐onset period (SOP) and during nocturnal REM sleep in two consecutive nocturnal recordings from 31 patients with NT1 (mean age 34 ± 15 years, 18 males) and a single nocturnal recording from 36 controls (mean age 38 ± 13 years, 21 males).

The SOP was defined as the first 10 min starting at the beginning of the first epoch of any sleep stage, and further divided into two consecutive 5‐min periods (SOP‐1 and SOP‐2); 1 min of artifact‐free quiet wakefulness after lights‐off was identified as well as 5 min of REM sleep in the middle of the night and another 5 min during the last REM sleep period. Electroencephalographic spectral analysis was performed using the C3/A2 channel.

Results

The SOP‐1 and, more strikingly, SOP‐2 had significantly less delta and sigma activity in patients with NT1 in the SOREMP condition versus both controls and patients with NT1 without SOREMP. SOP‐2 also showed less theta and alpha activity. Conversely, sigma and beta activity were more represented during SOREMP compared with the nocturnal REM period in patients with NT1.

Conclusions

The analysis of the SOP supports the concept that SOREMP is a different state compared with both nocturnal REM sleep and non‐REM sleep onset.
Evolution of defects in titanium grade 2 under Ti2+ ion irradiation
Authors: JOUANNY E. , DORIOT S. , MALAPLATE J. , DEHMAS M. , ALLAIS L. , THUAUT M. LE , MILLOT T.
Published: December 2016

The complexity and diversity of microstructure involved in titanium alloys make it rather difficult to quantitatively describe defect evolution due to irradiation. This paper focuses on defect evolutions of commercially pure titanium grade 2 under Ti2+ ion irradiation considering the effect of dose (0.6 and 3 dpa), temperature (300°C and 430°C) and flux (15:1 ratio). An irradiation damage profile was predicted using SRIM software to obtain a homogeneous damage on at least 500 nm depth for TEM observations and simulated using JANNUS‐Saclay facility. The details regarding the quantification methodologies of the defects from dark field images are provided, as are the origins of the associated uncertainties. In addition to a tangled dislocation network, presence of the ‐type and ‐component loops is observed. The latter was scarcely reported in the literature in the case of titanium alloys. At low temperature, the size distribution of the ‐type dislocation loops remained similar regardless of the dose and flux whereas these parameters have highly influence at 430°C. A widening of the size distribution and an increase of the threshold incubation dose (TID) was noted with the temperature. In the case of the ‐component loops, it was shown that the nucleation occurred in spite of the 0.6 dpa low dose.
Coping and caring: support resources integral to perioperative nurses during the process of organ procurement surgery
Authors: Smith Zaneta , Leslie Gavin , Wynaden Dianne
Published: December 2016

Aims and objectives

To discuss and explore the levels of support provided to perioperative nurses when participating in multi‐organ procurement surgery and the impact to their overall well‐being.

Background

Assisting within multi‐organ procurement surgical procedures has been recognised to impact on the well‐being of perioperative nurses leaving little opportunity for them to recover from their participation or to seek available support resources. To date, this area has remained largely unexplored with limited evidence of how nurses manage and cope with these procedures, in addition to the support received in the workplace.

Design

A qualitative grounded theory method.

Methods

The study was informed by perioperative nurses (n = 35) who had previous participatory experience in these surgical procedures from two Australian states. Theoretical sampling directed the collection of data via semistructured in‐depth interviews. Data were analysed using the constant comparative method.

Results

Three components of levels of support were identified from the data: lacking support within the operating room organisation; surgical team support and access to external professional support.

Conclusion

These findings offer new insights into how nurses manage and cope with their participation in organ procurement surgical procedures and what types of support resources can be seen as barriers or enablers to their overall experiences. The need for timely and adequate support is vital to their overall well‐being and future participation in organ procurement surgery. These findings have the potential to guide further research with implications for clinical initiatives and practices, looking at new ways of supporting perioperative nurses within the clinical environment both locally and internationally.

Relevance to clinical practice

Healthcare organisations need to acknowledge the emotional, psychosocial and psychological health and well‐being of nurses impacted by these surgical procedures and provide appropriate and timely clinical support within the work environment.
Experience and nursing needs of school‐age children undergoing lumbar puncture during the treatment of acute lymphoblastic leukaemia: a descriptive and qualitative study
Authors: Xie Anwei , Shan Yuying , Niu Mei′e , Chen Yi , Wang Xiya
Published: December 2016

Aims and objectives

To describe experiences and nursing needs of school‐age Chinese children undergoing lumbar puncture for the treatment of acute lymphoblastic leukaemia.

Background

Lumbar puncture is an invasive procedure, causing psychological changes and physical discomfort in patients. In a previous study, it was proved that distraction intervention, such as music therapy, relieves pain and anxiety. There is limited evidence regarding the experience and needs of school‐age children during lumbar puncture after being diagnosed with acute lymphoblastic leukaemia. To minimise their anxiety and pain during the procedure, it is important to collect information directly from these children.

Design

A descriptive qualitative research.

Methods

Twenty‐one school‐age children with acute lymphoblastic leukaemia participated in semi‐structured interviews at a Children's Hospital in China. Data were collected by an experienced and trained interviewer. Qualitative content analysis was chosen to describe experiences of children undergoing lumbar puncture.

Results

While undergoing lumbar puncture for the treatment of acute lymphoblastic leukaemia, school‐age Chinese children experienced complex psychological feelings (fear, tension, helplessness, sadness and anxiety). They also experienced physical discomfort. They had multipolar needs, such as information, communication, respect, self‐actualisation, environment and equipment.

Conclusions

This study identified important areas that must be closely monitored by healthcare staff, performing lumbar puncture on acute lymphoblastic leukaemia children. Thus, a successful and smooth procedure can be performed on these patients, and their quality of life can be improved.

Relevance to clinical practice

The experiences described in this study contribute to a better understanding of the needs of acute lymphoblastic leukaemia children undergoing lumbar puncture. They also provide valuable information to professional medical care staff that develops future nursing assessments.
Endothelin-1 (ET-1) stimulates carboxy terminal Smad2 phosphorylation in vascular endothelial cells by a mechanism dependent on ET receptors and de novo protein synthesis
Authors: Sharifat Narges , Mohammad Zadeh Ghorban , Ghaffari Mohammad-Ali , Dayati Parisa , Kamato Danielle , Little Peter J , Babaahmadi-Rezaei Hossein
Published: December 2016

Objective

G protein-coupled receptor (GPCR) agonists through their receptors can transactivate protein tyrosine kinase receptors such as epidermal growth factor receptor and serine/threonine kinase receptors most notably transforming growth factor (TGF)-β receptor (TβRI). This signalling mechanism represents a major expansion in the cellular outcomes attributable to GPCR signalling. This study addressed the role and mechanisms involved in GPCR agonist, endothelin-1 (ET-1)-mediated transactivation of the TβRI in bovine aortic endothelial cells (BAECs).

Method

The in-vitro model used BAECs. Signalling intermediate phospho-Smad2 in the carboxy terminal was detected and quantified by Western blotting.

Key finding

ET-1 treatment of BAECs resulted in a time and concentration-dependent increase in pSmad2C. Peak phosphorylation was evident with 100 nm treatment of ET-1 at 4–6 h. TβRI antagonist, SB431542 inhibited ET-1-mediated pSmad2C. In the presence of bosentan, a mixed ETA and ETB receptor antagonist ET-1-mediated pSmad2C levels were inhibited. The ET-mediated pSmad2C was blocked by the protein synthesis inhibitor, cycloheximide.

Conclusion

In BAECs, ET-1 via the ETB receptor is involved in transactivation of the TβRI. The transactivation-dependent response is dependent upon de novo protein synthesis.
Environmental Risk Factors for Diabetes Mellitus in Cats
Authors: Öhlund M. , Egenvall A. , Fall T. , Hansson‐Hamlin H. , Röcklinsberg H. , Holst B.S.
Published: December 2016

Background

Diabetes in cats resembles type 2 diabetes in people. The etiology is not fully understood, but both genetic and environmental factors are believed to contribute.

Objectives

To assess the associations of environmental risk factors with diabetes in cats.

Animals

Cats with a diagnosis of diabetes (n = 396) insured by a Swedish insurance company during years 2009–2013, and a control group (n = 1,670) matched on birth year.

Methods

A web‐based questionnaire was used in a case–control study. An invitation to participate was sent to owners of 1,369 diabetic cats and 5,363 control cats. The survey contained questions related to the cat's breed, age, sex, neutering status, body condition, housing, access to the outdoors, activity level, diet, eating behavior, feeding routine, general health, stressful events, other pets in the household, medications, and vaccination status. Data were analyzed by multiple logistic regression.

Results

Response rate was 35% for the diabetic group and 32% for the control group. Indoor confinement, being a greedy eater, and being overweight were associated with an increased risk of diabetes. In cats assessed by owners as being normal weight, there was an association between eating predominantly dry food and an increased risk of diabetes (Odds ratio 3.8; 95% confidence intervals 1.3–11.2).

Conclusions and Clinical Importance

Dry food is commonly fed to cats worldwide. The association found between dry food and an increased risk of diabetes in cats assessed as normal weight by owners warrants further attention.
Duodenitis‐Proximal Jejunitis in Horses After Experimental Administration ofClostridium difficileToxins
Authors: Arroyo L.G. , Costa M.C. , Guest B.B. , Plattner B.L. , Lillie B.N. , Weese J.S.
Published: December 2016

Background

Duodenitis‐proximal jejunitis (DPJ) is an acute sporadic gastrointestinal disorder of horses of unknown cause.

Hypothesis/Objectives

We hypothesize thatClostridium difficiletoxins are involved in the pathogenesis ofDPJin horses. The objective of this study was to determine whether experimentally deliveredC. difficiletoxins cause clinical signs and histologic lesions similar to those of naturally occurringDPJ.

Animals

Six healthy mature mixed breed horses.

Methods

Experimental study: animal model of animal disease. Fasted horses were administered crudeC. difficiletoxins via gastroscopy and monitored for up to 48 hour. Blood was collected for complete blood cell count, biochemistry profile, and plasma fibrinogen assay, and abdominal fluid was collected for cytologic analysis and total solids before and after toxin administration. Physical examination and abdominal ultrasonography were performed throughout the study period. Tissues were collected from the gastrointestinal tract and processed for routine histologic analysis, and lesions were scored.

Results

Clinical signs were observed in 2 of 6 horses that are typical although not specific for horses with naturally occurringDPJ. Histopathologic lesions were observed in 6 of 6 horses and were similar to those reported in horses with naturally occurringDPJ. Two horses were severely affected.

Conclusions and Clinical Importance

Duodenitis‐proximal jejunitis is likely a syndrome with multiple causes that result in the same clinical and pathologic findings, and our data suggest that the toxins ofC. difficilerepresent one cause of this syndrome. Toxin dose and variation in individual animal susceptibility might affect the clinical signs and lesions after administration ofC. difficiletoxins.
Expressions of cultural safety in public health nursing practice
Authors: Richardson Anna , Yarwood Judy , Richardson Sandra
Published: December 2016

Cultural safety is an essential concept within New Zealand nursing that is formally linked to registration and competency‐based practice certification. Despite its centrality to New Zealand nursing philosophies and the stated expectation of cultural safety as a practice element, there is limited evidence of its application in the literature. This research presents insight into public health nurse's (PHN) experiences, demonstrating the integration of cultural safety principles into practice. These findings emerged following secondary analysis of data from a collaborative, educative research project where PHNs explored the use of family assessment tools. In particular, the 15‐minute interview tool was introduced and used by the PHNs when working with families. Critical analysis of transcribed data from PHN interviews, utilising a cultural safety lens, illuminated practical ways in which cultural safety concepts infused PHN practice with families. The themes that emerged reflected the interweaving of the principles of cultural safety with the application of the five components of the 15‐minute interview. This highlights elements of PHN work with individuals and families not previously acknowledged. Examples of culturally safe nursing practice resonated throughout the PHN conversations as they grappled with the increasing complexity of working with a diverse range of families.
Canine and feline colostrum
Authors: Chastant‐Maillard S , Aggouni C , Albaret A , Fournier A , Mila H
Published: December 2016

Contents

Puppy and kitten survival over the first weeks is particularly dependent on colostrum, a specific secretion of the mammary gland produced during the first 2 days post‐partum. Colostrum is a source of nutrients and immunoglobulins. It also contributes to the digestive tract maturation. Colostrum differentiates from milk mainly based on its concentration in immunoglobulins G: 20–30 g/L in dog colostrum, 40–50 g/L in cats’ vs <1 g/L in milk. IgG concentration rapidly drops after parturition (−50% in 24 hr). Immune quality of colostrum is highly variable between bitches, with no relationship with maternal blood IgG level, dam's age, breed size or litter size. In addition to systemic immune protection, colostrum also plays a major role for local digestive protection, due to IgA, lysozyme, lactoferrin, white blood cells and various cytokines. Energetic concentration of canine and feline colostrum is not superior to that of mature milk. It depends on colostrum fat concentration and is affected by breed size (higher in breeds <10 kg adult body weight). As puppies and kittens are almost agammaglobulinemic at birth, transfer of IgG from their digestive tract into their bloodstream is crucial for their survival, IgG absorption ending at 12–16 hr after birth. Energetic supply over the two first days of life, as evidenced by growth rate over the two first days of life, also affects risk of neonatal mortality. Early and sufficient suckling of colostrum is thus the very first care to be provided to newborns for their later health and survival.
Evaluating Year-end Oral Reading Records of First Graders in terms of Prosody Proficiency
Authors: Kocaarslan Mustafa , Ergün Akile
Published: December 2016

Prosody is evaluated as an important factor in fluent reading and in literature it is expressed as a significant reading skill that affects comprehension. Prosody -described as a fluent reading ability of a reader with suitable sentences and expressions- includes stress, intonation, duration (time passed on voicing a word) and pausing properties that contribute to effective reading of a text. First grade students are supposed to have fluent reading abilities at the end of the year and they are expected to develop effective prosodic reading. Therefore, the aim of this study is to examine first grade students’ oral reading performances in terms of prosodic competences. Study sample in this study which has been conducted using descriptive survey model consists of 49 first grade students who participated in the study voluntarily in four different classes in a primary school in the city centre of Bartin in Turkey. For the evaluation of the reading prosodies of the students, their oral reading performances of a narrative and an expository text are recorded for one minute with a video camera and these records are evaluated with reading prosody rubric. As a result of the analysis, it is observed that students’ reading prosody score means are low in both narrative and expository texts. According to reading prosody scale, it appears that 59% of the students are at low level in narrative text and 41% of the students are at low level in expository text. Additionally, as a result of Mann-Whitney U test it appears that gender of the students does not make a significant difference in oral reading prosodies of the students in both narrative and expository texts.
Critical Plate Thickness for Energy Dissipation During Sphere–Plate Elastoplastic Impact Involving Flexural Vibrations
Authors: Patil Deepak , Fred Higgs C.
Published: December 2016

Solid processing storage and conveying units (e.g., hoppers, silos, tumblers, etc.) often involve the collision of granular media with relatively thin walls. Therefore, the impact of a sphere with a thin plate is a problem with both fundamental and practical importance. In the present work, the normal elastoplastic impact between a sphere and a thin plate is analyzed using an explicit finite element method (FEM). The impact involves plastic deformation and flexural vibrations, which when combined results in significant energy dissipation. One way to quantify the energy dissipation is to employ the coefficient of restitution (COR), which is also a key input parameter needed in various granular flow models. The results were validated against the available experimental data. It is observed that, in addition to material properties and impact parameters, the energy dissipation is strongly dependent on the ratio of plate thickness to sphere diameter. A comprehensive parametric study is conducted to evaluate the effect of material properties, geometry, and impact parameters on the energy dissipation. For the impact velocities commonly observed in granular systems (V = 5 m/s or less), it was determined that the energy lost to flexural vibrations can be neglected if the plate thickness is more than twice the sphere diameter, i.e., tcr > 2d. In this scenario, the mode of energy dissipated is primarily due to the plasticity effects.
Diethyl Ether as an Ignition Enhancer for Naphtha Creating a Drop in Fuel for Diesel
Authors: Vallinayagam R. , Vedharaj S. , Sarathy S. Mani , Dibble Robert W.
Published: December 2016

Direct use of naphtha in compression ignition (CI) engines is not advisable because its lower cetane number negatively impacts the auto ignition process. However, engine or fuel modifications can be made to operate naphtha in CI engines. Enhancing a fuel’s auto ignition characteristics presents an opportunity to use low cetane fuel, naphtha, in CI engines. In this research, Di-ethyl ether (DEE) derived from ethanol is used as an ignition enhancer for light naphtha. With this fuel modification, a “drop-in” fuel that is interchangeable with existing diesel fuel has been created.

The ignition characteristics of DEE blended naphtha were studied in an ignition quality tester (IQT); the measured ignition delay time (IDT) for pure naphtha was 6.9 ms. When DEE was added to naphtha, IDT decreased and D30 (30% DEE + 70% naphtha) showed comparable IDT with US NO.2 diesel. The derived cetane number (DCN) of naphtha, D10 (10% DEE + 90% naphtha), D20% DEE + 80% naphtha) and D30 were measured to be 31, 37, 40 and 49, respectively. The addition of 30% DEE in naphtha achieved a DCN equivalent to US NO.2 diesel.

Subsequent experiments in a CI engine exhibited longer ignition delay for naphtha compared to diesel. The peak in-cylinder pressure is higher for naphtha than diesel and other tested fuels. When DEE was added to naphtha, the ignition delay shortened and peak in-cylinder pressure is reduced. A 3.7% increase in peak in-cylinder pressure was observed for naphtha compared to US NO.2 diesel, while D30 showed comparable results with diesel. The pressure rise rate dropped with the addition of DEE to naphtha, thereby reducing the ringing intensity. Naphtha exhibited a peak heat release rate of 280 kJ/m3deg, while D30 showed a comparable peak heat release rate to US NO.2 diesel. The amount of energy released during the premixed combustion phase decreased with the increase of DEE in naphtha. Thus, this study demonstrates the suitability of DEE blended naphtha mixtures as a “drop-in” replacement fuel for diesel.
Efficacy of Add-On Hydrous Ethanol Dual Fuel Systems to Reduce NOx Emissions From Diesel Engines
Authors: Hwang Jeffrey T. , Nord Alex J. , Northrop William F.
Published: December 2016

Aftermarket dual-fuel injection systems using a variety of different fumigants have been proposed as alternatives to expensive after-treatment to control NOX emissions from legacy diesel engines. However, our previous work has shown that available add-on systems using hydrous ethanol as the fumigant achieve only minor benefits in emissions without recalibration of the diesel fuel injection strategy. This study experimentally re-evaluates a novel aftermarket dual-fuel port fuel injection (PFI) system used in our previous work, with the addition of higher flow injectors to increase the fumigant energy fraction (FEF), defined as the ratio of energy provided by the hydrous ethanol on a lower heating value (LHV) basis to overall fuel energy. Results of this study confirm our earlier findings that as FEF increases, NO emissions decrease, while NO2 and unburned ethanol emissions increase, leading to no change in overall NOX. Peak cylinder pressure and apparent rates of heat release are not strongly dependent on FEF, indicating that in-cylinder NO formation rates by the Zel’dovich mechanism remains the same. Through single zone modeling, we show the feasibility of in-cylinder NO conversion to NO2 aided by unburned ethanol. The modeling results indicate that NO to NO2 conversion occurs during the early expansion stroke where bulk gases have temperature in the range of 1150–1250 K. This work conclusively proves that aftermarket dual fuel systems for fixed calibration diesel engines cannot reduce NOX emissions without lowering peak temperature during diffusive combustion responsible for forming NO in the first place.
Free-Piston Linear Generator and the Development of a Solid Lubrication System
Authors: Virsik Roman , Rinderknecht Frank , Friedrich Horst E.
Published: December 2016

The free piston linear generator is a new electromechanical generator. It converts chemical energy into electrical energy by means of a combustion process, a linear generator and a gas spring. Thereby the technology aims to have better properties than other electromechanical generators. Therefore this publication deals with the explanation of the concept, the characteristics of a free piston linear generator and one of the challenges in the development. In order to use a port scavenging the emission issue is the challenge and has to be solved. One possible solution is the use of solid lubricants to substitute motor oil. The development methodology and one aspect of the development will be explained.
Power Maximization of a Heavy Duty Diesel Organic Rankine Cycle Waste Heat Recovery System Utilizing Mechanically Coupled and Fully Electrified Turbine Expanders
Authors: Xu Bin , Yebi Adamu , Onori Simona , Filipi Zoran , Liu Xiaobing , Shutty John , Anschel Paul , Hoffman Mark
Published: December 2016

This paper presents steady state power optimization for an Organic Rankine Cycle (ORC) waste heat recovery (WHR) system in heavy-duty diesel (HDD) applications and examines attainable power levels. Both recirculated and tail pipe exhaust gas streams are utilized as heat sources via a parallel evaporator configuration. A dynamic, physics-based ORC model is utilized to determine optimized net power production. The optimization variables include: working fluid pump speed, mass flow distribution ratio for the parallel evaporators, turbine speed, and the pump speed of condenser cooling fluid. A sensitivity analysis is conducted for all optimization variables. Working fluid pump speed and expansion turbine speed are demonstrated as the most sensitive variables. Sensitivity results indicate increasing system power production as the working fluid mass flow rate increases. A map is developed to identify optimal and safe ORC operating regions for a given engine cycle. Based on the sensitivity analysis working fluid pump speed is selected as the variable of interest in the steady state optimization and results indicate that system power generation could be improved by as much as 25%.

Analysis of two quasi steady operational cycles, a multi-mode and a constant speed variable load are conducted. ORC power results indicate that a speed-constrained, mechanically coupled turbine expander operates in its peak efficiency zone to produce maximum power output for the steady-state cycles tested. These steady state power optimization results can be used for future power optimization during engine transients.
A One-Way Coupled Volume of Fluid and Eulerian-Lagrangian Method for Simulating Sprays
Authors: Quan Shaoping , Senecal Peter Kelly , Pomraning Eric , Xue Qingluan , Hu Bing , Rajamohan Divakar , Deur John M. , Som Sibendu
Published: December 2016

Volume of Fluid (VOF) and Eulerian-Lagrangian (EL)/Discrete Droplet Methods (DDM) are two of the most widely used methods in spray simulations. It is well known that these two methods have their pros and cons. VOF is good at capturing the transient detailed flow physics, while it is usually very expensive. EL is very efficient; however, to inject spray parcels, some experimental/pre-computed information is needed, such as rate of injection, and/or the parcel radius distributions, etc. It is often the case, the detailed fluid flow information at the nozzle exit, which is essential for downstream droplet breakup and coalescence, cannot be accounted in the EL method. In this paper, we developed a one-way coupled approach, in which VOF is employed to compute the detailed fluid field in the injector and this fluid information is then utilized by EL for the injection of parcels at the nozzle exit. The one-way coupled approach is used to calculate some ECN (Engine Combustion Network) spray cases, such as Spray A and Spray H. The simulated results are compared to the experimental data, and satisfactory agreement is obtained.
Quasi-D Diesel Engine Combustion Modeling With Improved Diesel Spray Tip Penetration, Ignition Delay and Heat Release Sub-Models
Authors: Xu Shuonan , Yamakawa Hirotaka , Nishida Keiya , Filipi Zoran
Published: December 2016

Increasingly stringent fuel economy and CO2 emission regulations provide a strong impetus for development of high efficiency engine technologies. Diesel engines dominate the heavy duty market and significant segments of the global light duty market due to their intrinsically higher thermal efficiency compared to spark ignited (SI) engine counterparts. Predictive simulation tools can significantly reduce the time and cost associated with optimization of engine injection strategies, and enable investigation over a broad operating space unconstrained by availability of prototype hardware. In comparison with 0-D/1-D and 3-D simulations, Quasi-D models offer a balance between predictiveness and computational effort, thus making them very suitable for enhancing the fidelity of engine system simulation tools. A most widely used approach for diesel engine applications is a multi-zone spray and combustion model pioneered by Hiroyasu and his group. It divides diesel spray into packets and tracks fuel evaporation, air entrainment, gas properties and ignition delay (induction time) individually during the injection and combustion event. However, original sub-models are not well suited for modern diesel engines, and the main objective of this work is to develop a multi-zonal simulation capable of capturing the impact of high-injection pressures and Exhaust Gas Recirculation (EGR). In particular, a new spray tip penetration sub-model is developed based on measurements obtained in a high-pressure, high-temperature constant volume combustion vessel for pressures as high as 1450 bar. Next, ignition delay correlation is modified to capture the effect of reduced oxygen concentration in engines with EGR, and an algorithm considering the chemical reaction rate of hydrocarbon-oxygen mixture improves prediction of the heat release rates. Spray and combustion predictions were validated with experiments on a single-cylinder diesel engine with common rail fuel injection, charge boosting, and EGR.
Observer Based Cylinder Air Charge Estimation for Spark Ignition Engines
Authors: Wang Zhe , Zhu Qilun , Prucka Robert , Prucka Michael , Dourra Hussein
Published: December 2016

Spark ignition engine in-cylinder air charge estimation is important for air-to-fuel ratio control, maintaining high after-treatment efficiency, and determination of current engine torque. Current cylinder air charge estimation methodologies generally depend upon either a mass air flow (MAF) sensor or a manifold absolute pressure (MAP) sensor individually. Methods based on either sensor have their own advantages and disadvantages. Some production vehicles are equipped with both MAF and MAP sensors to offer air charge estimation and other benefits. This research proposes several observer based cylinder air charge estimation methods that take advantage of both MAF and MAP sensors to potentially reduce calibration work while providing acceptable transient and steady-state accuracy with low computational load. This research also compares several common air estimation methods with the proposed observer based algorithms using steady-state and transient dynamometer tests and a rapid-prototype engine controller. With appropriate tuning the proposed observer based methods are able to estimate cylinder air charge mass under different engine operating conditions based on the manifold model and available sensors. Methods are validated and compared based on a continuous tip-in tip-out operating condition.
Study on the Simulation Method of Compressor Aerodynamic Noise Based on CFD and IBEM
Authors: Chen Liu , Yipeng Cao , Wenjian Sun , Wenping Zhang , Pingjian Ming , Guang Lin
Published: December 2016

Turbocharger compressor aerodynamic noise has been one of the major noise sources of diesel engine. It is necessary to study the characteristics of turbocharger fluid flow and radiation noise for its effective noise control. In this paper, a new for predicting compressor aerodynamic noise is presented, which combined the computational fluid dynamic (CFD) and indirect boundary element method (IBEM). The unsteady viscous flow in compressor was simulated based on the finite volume method. In addition, the periodic pressure fluctuation of the rotor inlet and blades were used to compressor radiation noise field simulation by indirect boundary element method. In order to prove the feasibility of numerical simulation, the acoustics experimental device for compressor aerodynamic noise experiment was built and the sound pressure of turbocharger were tested. The trend of simulation results and amplitude level in blade passing frequency (BPF) coincide with the experiment results. It indicates that the coupling method is more effective and accurate in turbocharger noise prediction.
Electric Turbo Compounding Applied to a CI Engine: A Numerical Evaluation of Different Layouts
Authors: Pasini Gianluca , Frigo Stefano , Antonelli Marco
Published: December 2016

At present, the application of turbocharging in compression ignition (CI) engines represents almost all of the applications, especially for transportation where fuel efficiency and low emissions are the main targets. Following this approach, the possibility to couple an electric drive to the turbocharger (electric turbo compound, ETC) to recover the residual energy of the exhaust gases is becoming more and more attractive, as demonstrated by several studies around the world.

The present paper shows the first numerical results of a research program under way which is focused on the comparison of the benefits resulting from the application of two ETC configurations to a four cylinders CI engine (1561 cm3). In the first configuration, called single-ETC, a variable geometry turbocharger (VGT) is coupled to an electric generator (mechanic connection); in the second, called dual ETC, the two turbomachines (the variable nozzle turbine and the compressor) are separated and each one is coupled to its own electric machine.

Starting from the experimental maps of the turbine and compressor, the complete engine model was created using the AVL BOOST one-dimension code. Compared with the no-ETC engine, the adoption of the single-ETC shows interesting benefits in term of energy recovery at the highest engine speeds and loads, with consequent decrease of fuel consumption. Dual ETC allows the operation of turbine and compressor at different speeds with further reduction of the total brake specific fuel consumption.
Addition of Exhaust Gas Recirculation Onto a Large-Bore, Two-Stroke Natural Gas Engine, and its Effects on Fuel Consumption, Emissions, and Combustion
Authors: Johnson Derek , Besch Marc , Fowler Nathaniel , Heltzel Robert , Covington April
Published: December 2016

The focus of this research was to examine the effects of adding exhaust gas recirculation (EGR) on a large bore 2-stroke, lean-burn natural gas (2SLB) engine in its stock configuration, using a previously determined optimal spark plug. EGR has been a common emissions reduction technology used for on-road gasoline, natural gas, and diesel fueled vehicles. EGR — both cooled and uncooled — is found in nearly all on-road and many off-road engines. The optimal spark plug was found in other research and it was tested with various rates of EGR. The test platform was a 1971 Cameron AJAX-E42 single-cylinder engine — common to the natural gas industry. The engine had a bore and stroke of 8.5 × 10 inches, respectively. The engine displacement was 567 cubic inches with a trapped compression ratio of 6:1. The engine was modified to include electronic spark plug timing capabilities along with a mass flow controller to ensure accurate fuel delivery. Each EGR configuration was examined at spark timings of 14, 11, and 8 CAD BTDC. Tests were conducted using an air-cooled, eddy-current power absorber at an engine speed of 525 RPM and load of 400 1b.-ft. of torque. Due to its large thermal inertia, the engine was operated for three hours prior to data collection to ensure representative and operation. In-cylinder pressure data were collected using a piezoelectric pressure transducer at increments of 0.25 CAD. Various levels of EGR and spark timing conditions were evaluated against engine performance including both regulated and unregulated exhaust emissions. Volumetric EGR rates of 2.5% showed reduced NOx emissions and improved fuel efficiency while rates of 5% did not yield NOx reductions.