bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploration of a nurse practitioner‐led phase two cardiac rehabilitation programme on attendance and compliance
Authors: O’Toole Kathryn , Chamberlain Diane , Giles Tracey
Published: December 2019

Aims and Objectives

To evaluate the impact of a nurse practitioner‐led phase two cardiac rehabilitation and secondary prevention programme on attendance and compliance.

Background

Despite strong evidence for the benefits of cardiac rehabilitation, attendance/completion rates remain low. Nurse practitioner‐led services have been reported as more effective than physician‐led services at increasing patient adherence to evidence‐based recommendations. However, nurse practitioner‐led programmes are uncommon and there appears to be no current evidence examining the impact of these programmes on attendance/completion rates.

Methods

A retrospective audit of the Country Access to Cardiac Health (CATCH) database was undertaken to identify patients who attended a nurse practitioner‐led cardiac rehabilitation programme between April 2014 and May 2016. Data from key performance indicators were exported to Stata/SE 15.0. The study utilised the Strengthening the Reporting of OBservational Studies in Epidemiology (STROBE) Statement: guidelines for reporting observational studies to ensure quality reporting during this study (See DataS1).

Results

Seventy‐seven per cent (n = 199) of participants were men, and participants had a mean age of 67 years. Half (52.5%) of participants completed all CR sessions. Male participants (78%) were more likely to complete the CR programme as compared with women (67%).

Participants with a family history of cardiovascular disease and a higher number of risk factors at baseline were more likely to commence and complete the programme. Attendance and completion had a positive impact on smoking cessation.

Conclusions

The nurse practitioner‐led programme evaluated in this study demonstrated high levels of attendance and completion rates compared to standard programmes. This high attendance/completion rate could in turn decrease the rate of subsequent cardiac events and improve mortality and morbidity rates.

Relevance to clinical practice provides valuable insights into the effectiveness of nurse practitioner‐led cardiac rehabilitation and secondary prevention on attendance/complete rates. These findings could guide future research and clinical practice development.
Workplace Flexibility and Worker Well‐Being by Gender
Authors: Kim Jaeseung , Henly Julia R. , Golden Lonnie M. , Lambert Susan J.
Published: December 2019

Objective

The study examines the associations between two distinct forms of workplace flexibility—flexible schedules and working at home—and workers' well‐being, with special attention to the distinct reasons for working at home and gender differences.

Background

Workplace flexibility can be a key resource to manage work and family responsibilities. However, there are gaps in knowledge regarding the types of flexibility that provide either a benefit or disadvantage for workers. In particular, insufficient attention has been paid to different reasons employees have for working at home and their implications.

Method

Using the General Social Survey, we created a pooled sample across the four waves of data (2002, 2006, 2010, and 2014, N = 6,945). Workers' well‐being was measured with job satisfaction, job stress, daily fatigue, and work‐to‐family conflict. Multivariate regression analysis and several sensitivity tests were conducted.

Results

The study found benefits of flexible schedules for work‐related well‐being. Working at home as part of one's job had some benefits, but working at home to catch up on work had consistent disadvantages for worker well‐being. Moreover, the ability to adjust start and end times of work and working at home to catch up on work were associated with elevated work‐to‐family conflict, particularly for female workers.

Conclusion

The findings suggest the potential advantages and unintended consequences of different flexibility arrangements for workers, and these implications may differ by gender.
Factors influencing the occurrence of neonatal procedural pain
Authors: Wang Yajing , Li Yang , Sun Jing , Feng Shuju , Lian Dongmei , Bo Haixin , Li Zhenghong
Published: December 2019

Objectives

The objective of this study was to describe the occurrence of neonatal procedural pain and explore the factors that influence the frequency of painful procedures.

Design

A descriptive prospective epidemiologic study.

Setting

NICU at a general hospital in China.

Methods

A demographic and diagnosis or illness information questionnaire and an occurrence of procedural pain questionnaire specifically designed for this study were used to record the current status of neonatal procedural pain. The neonatal infant pain scale (NIPS) was used to measure pain intensity. A multiple linear regression model was used to explore the factors influencing the frequency of painful procedures.

Results

One hundred and twenty neonates experienced a total of 16,840 painful procedures. Each neonate was exposed to a median (IQR) of 66.5(27,154.75) painful procedures during hospitalization and a median (IQR) of 13(11, 19) painful procedures. All 27 different procedures were considered painful, and 70.37% (19/27) of these procedures caused severe pain. Overall, the mean NIPS score of the 27 procedures was 5.04 ± 1.52 with a range from 0 to 7. Respiratory support, age, and length of hospital stay were factors influencing the frequency of painful procedures.

Conclusions

NICU neonates experience pain at a high frequency and intensity during hospitalization. Respiratory support, age, and length of hospital stay were factors influencing the frequency of painful procedures. Strategies are needed to bridge the gap between practice and the evidence‐based guidelines.
Collaborative caregiving of parents who have an infant with congenital heart disease
Authors: Pridham Karen F. , Harrison Tondi M. , Brown Roger , Mussatto Kathleen
Published: December 2019

Purpose

Describe collaborative caregiving of the parents of an infant with congenital heart disease (CHD) with partner, health‐care clinicians, and substitute caregivers (SC).

Design and Methods

In a national online survey, 53 mothers and 12 fathers described collaborative caregiving for infants after CHD intervention with respect to facets of Bowlby's concept of the internal working model of caregiving. Parents identified concern for 24 everyday common problems or goals (i.e., issues; 10 for partner, 9 for clinician, 5 for SC), rated issue importance and difficulty, indicated an intention for seeking and using help (help use), and identified help source.

Results

All survey items were a concern to at least 11 parents. Most prominently, all five of the SC items were identified by at least 44% of the parents as a concern. Everyday, common problems and goals were generally reported to be more important than difficult. Two items identified as partner issues, “Talking about life change” and “Handling stress,” were a concern for about 50% of parents and identified by at least 74% as very important and 72% as moderately to greatly difficult. Help use was highest for SC items followed by items related to the partner. The partner was most frequently identified as a help source.

Practice Implications

Nurses are in a position to assess and support parent collaboration within partner, clinician, and SC relationships for everyday problems and goals. The survey questions, with further development and testing, could be used for clinician assessment and tailoring of intervention to support parents’ collaborative caregiving for infants with CHD.
Cardiac cachexia in cats with congestive heart failure: Prevalence and clinical, laboratory, and survival findings
Authors: Santiago Sasha L. , Freeman Lisa M. , Rush John E.
Published: December 2019

Background

Cardiac cachexia is common in people and dogs with congestive heart failure (CHF). However, the prevalence and effects of cardiac cachexia in cats are unknown.

Objectives

To determine the prevalence of cachexia and its associations with clinical laboratory and survival data in cats with CHF.

Animals

One hundred twenty‐five cats with CHF.

Methods

Medical records of cats evaluated during a 40‐month period were retrospectively reviewed to identify cats with cardiac cachexia using 7 different definitions. Clinical, laboratory, and survival data were compared between cats with and without cachexia.

Results

Prevalence of cachexia ranged from 0 to 66.7% for the 7 definitions, with a prevalence of 41.6% using muscle condition score (MCS). Cats with cachexia (determined by MCS) were older (P < .001), more likely to have pleural effusion (P= .003), had significantly higher blood urea nitrogen (P < .001) and neutrophil concentrations (P= .01), and significantly lower body condition score (P < .001), body weights (P < .001), hematocrit (P= .007), and hemoglobin concentrations (P= .009). Survival time for cats with cachexia (determined by MCS) was significantly shorter than for cats without cachexia (P= .03). Cats that were underweight (P= .002) and cats with dilated cardiomyopathy (DCM) also had shorter survival times (P= .04).

Conclusions and Clinical Importance

The association between cachexia and reduced survival time emphasizes the importance of identifying and addressing this common problem in cats with CHF.
Marine species formation along the rise of Central America: The anomuran crab Megalobrachium
Authors: Hiller Alexandra , Lessios Harilaos A.
Published: December 2019

The evolution of marine neotropical shallow water species is expected to have been greatly affected by physical events related to the emergence of the Central American Isthmus. The anomuran crab Megalobrachium, a strictly neotropical porcellanid genus, consists of four species in the West Atlantic (WA) and nine in the East Pacific (EP). Dispersal is limited to a relatively short planktonic phase, which lasts approximately two weeks. We obtained DNA sequences of three mitochondrial and two nuclear genes of all but one species of Megalobrachium to construct a time‐calibrated phylogeny of the genus and its historical phylogeography, based on the reconstruction of ancestral areas. The topology of the phylogenetic trees of Megalobrachium produced by Bayesian Inference (BI) and Maximum Likelihood (ML) were virtually congruent. The genus is monophyletic with respect to other porcellanids. Ancestral area reconstruction indicates that it arose in the eastern Pacific 18 million years ago and diversified into at least 13 species that are currently formally recognized and three additional species indicated by our data. Most morphological variation appears to have followed phylogenetic differentiation, though some cryptic speciation has also occurred. Four geminate clades in this genus implicate the gradual emergence of the Central American Isthmus in this diversification, but events preceding the final separation of the oceans as well as within‐ocean events after the cessation of water connections were also important.
Understanding the professional satisfaction of hospital trainees in Australia
Authors: Lennon Matthew J. , McGrail Matthew R. , O'Sullivan Belinda , Tan Amelia , Mok Claire , Suttie Joseph J. , Preddy John
Published: December 2019

Context

Ensuring that specialty trainees are professionally satisfied is not only important from the point of view of trainee well‐being, but is also critical if health systems are to retain doctors. Despite this, little systematic research in specialist trainees has identified policy‐amenable factors correlated with professional satisfaction. This study examined factors associated with trainee professional satisfaction in a national Australian cohort.

Methods

This study used 2008‐2015 data from the Medicine in Australia: Balancing Employment and Life (MABEL) survey, a national study of doctor demographics, characteristics and professional and personal satisfaction. Our study examined specialist trainees using a repeat cross‐sectional method pooling first responses across all waves. A multivariate logistic regression analysis was used to assess correlates with professional satisfaction.

Results

The three factors most strongly correlated with professional satisfaction were feeling well supported and supervised by consultants (odds ratio [OR] 2.59, 95% confidence interval [CI] 2.42‐2.77), having sufficient study time (OR 1.54, 95% CI 1.40‐1.70) and self‐rated health status (OR 1.65, 95% CI 1.53‐1.80). Those working >56 hours per week were significantly less professionally satisfied (OR 0.76, 95% CI 0.70‐0.84) compared with those working the median work hours (45‐50 hours per week). Those earning in the lower quintiles, those earlier in their training and those who had studied at overseas universities were also significantly less likely to be satisfied.

Conclusions

Our study suggests that good clinical supervision and support, appropriate working hours and supported study time directly impact trainee satisfaction, potentially affecting the quality of clinical care delivered by trainees. Furthermore, the needs of junior trainees, overseas graduates and those working >56 hours per week should be given particular consideration when developing well‐being and training programmes.
Meningioma with rosettes: A rare morphologic pattern
Authors: Poyuran Rajalakshmi , Thomas Bejoy , Abraham Mathew , Narasimhaiah Deepti
Published: December 2019

We describe a case of WHO grade I transitional meningioma with rosettes in a 68‐year‐old woman. The rosettes were composed of meningothelial cells arranged around dense collagenous cores. Even though the presence of rosettes in tumors of the brain and spinal cord is an indication of neuronal or ependymal differentiation, they are also known to occur in tumors of other lineages. Rosette is an uncommon morphological pattern in meningiomas, with only few cases reported in the literature.
RhoG/Rac1 signaling pathway involved in migration and invasion of salivary adenoid cystic carcinoma cells
Authors: Xu Ze‐dong , Hao Ting , Gan Ye‐Hua
Published: December 2019

Objectives

This study aimed to explore whether RhoG/Rac1 was involved in migration and invasion of salivary adenoid cystic carcinoma (SACC).

Materials and Methods

RhoG and Rac1 were evaluated in two SACC cell lines, namely SACC‐83 and SACC‐LM, with low and high rates of lung metastasis, respectively. Functional changes were evaluated using cell proliferation, transwell, and wound‐healing assays, and molecular events were investigated using real‐time PCR and Western blot assays.

Results

RhoG and Rac1 were highly expressed and more activated in SACC‐LM cells than in SACC‐83 cells. RhoG overexpression promoted SACC‐83 cell migration and invasion through activating Rac1. The knockdown of RhoG or Rac1 partially blocked epiregulin‐induced migration and invasion in SACC‐83 cells. Epiregulin‐induced activation of RhoG/Rac1 in SACC‐83 cells was blocked by a Src inhibitor, or an AKT inhibitor or AKT siRNA, or an ERK1/2 inhibitor. Moreover, the epiregulin‐induced phosphorylation of AKT and ERK1/2 in SACC‐83 cells was blocked by a Src inhibitor, and the epiregulin‐induced phosphorylation of ERK1/2 was blocked by an AKT inhibitor or AKT siRNA. Overexpression of activated AKT induced activation of ERK1/2 and RhoG.

Conclusions

RhoG/Rac1 signaling pathway was involved in SACC cell migration and invasion. RhoG/Rac1 at least partially mediated epiregulin/Src/AKT/ERK1/2 signaling to promote SACC cell migration and invasion.
Relationships within MOMS Orange County care coordinated home visitation perinatal program
Authors: Guo Yuqing , Bender Miriam , Rousseau Julie , Kehoe Priscilla , Lee Jung‐Ah , Pimentel Pamela , Bojorquez Yvette , Silva Michele , Olshansky Ellen
Published: December 2019

Purpose

The study aimed to examine how registered nurses (RNs) and paraprofessional home visitors (PHVs) work together as a team to care for underserved perinatal women in a coordinated home visitation program.

Design and Methods

Qualitative methods were used to understand the perspectives of three RNs and twenty PHVs who worked at MOMS Orange County, a community‐based perinatal health program. Individual one‐on‐one interviews were administered with the RNs and focus groups with the PHVs. Qualitative content analysis was conducted to synthesize themes.

Results

RNs perceived themselves as educators, mentors, and supervisors. PHVs thought of themselves as supporters, coaches, and advocates. Interdependence and proactive communication were favorable characteristics of the relationship in which RNs trained PHVs to provide health education. The positive interactions between RNs and PHVs appeared to enhance the client‐healthcare provider connection.

Conclusions

Our study is one of the first to describe relationships and communication patterns among the healthcare team in a coordinated home visitation program in the United States. Future studies should examine how additional members of the team, including clients and healthcare providers, view their experiences with a home visitation program.
Kidnap and ransom insurance: A strategically useful, often undiscussed, marketplace tool for international operations
Authors: Brockett Patrick L. , Golden Linda L. , Zaparolli Stephan , Lum Jack M.
Published: December 2019

With kidnaping rates rising, the disruptive forces of kidnaping threaten the stability and success of corporate investment projects and put stress on appropriate corporate governance response methodologies. While kidnaping targets vary considerably among countries where it frequently occurs, most often the goal of kidnapers is money from ransom payments. Financial consequences of a kidnap ransom payment can be severe for companies, and psychological damage can be lasting to employees and their families. Given the increasingly global nature of business and increasing expansion into less politically and legally stable emerging markets, kidnap, ransom, and extortion pose a problem for management of corporations wishing to take advantage of emerging market opportunities. Kidnap and Ransom (K&R) Insurance is a risk control technique used by about 75% of Fortune 500 companies, nongovernmental organizations, and an increasing percentage of small to medium sized companies. It is a bundled package policy that includes the purchase of an insurance policy to indemnify the company for the costs of kidnap, ransom, and extortion. Such policies can also provide protective consulting beforehand, provide crisis response and negotiation assistance, as well as psychological support services after the fact. In this paper, we describe the K&R policy, its history, other nonfinancial corporate benefits provided by K&R policies, and discuss its use by corporate managers for the benefit of corporate, financial, and personnel stability. It can also be used in course on managing international risk.
The role of gut microbiota in atopic asthma and allergy, implications in the understanding of disease pathogenesis
Authors: Salameh Mohammad , Burney Zain , Mhaimeed Nada , Laswi Ibrahim , Yousri Noha A. , Bendriss Ghizlane , Zakaria Dalia
Published: December 2019

Asthma is a clinical syndrome characterized by chronic airway inflammation. There is mounting evidence on the role of microbiota in the development of asthma. This review focuses on the role of microbiota in maintaining the integrity of the epithelia and their role in regulating the immune response. The review compiles data from multiple studies on the role of microbiota in the innate immune response and the development and differentiation of CD4+ T cells, a major component of the adaptive arm of the immune response. As a result of dysbiosis, invariant natural killer T cells may induce T helper 2 cell differentiation and immunoglobulin E isotype switching through the release of interleukin‐4 and interleukin‐13. Furthermore, degradation of immunoglobulin A antibodies, increased circulating mast cells and basophils, and inflammation are among other mechanisms by which dysbiosis can induce or exacerbate asthma. After explaining the underlying mechanisms, the review derives conclusions from studies that investigate dysbiosis in infancy and the development of asthma later in life. The review also includes studies that investigate asthmatic mothers and the development of asthma in children and the role of dysbiosis in that regard. Finally, the review explains the statistical relationship between eczema and asthma through multiple studies that investigate the role of dysbiosis in both atopic states. This review provides insight into the role of dysbiosis in asthma, and an understanding that is required to establish clinical trials which aim to modulate the gut microbiota as a means of preventing and treating asthma.
Oral treatment with Aloe polysaccharide ameliorates ovalbumin‐induced atopic dermatitis by restoring tight junctions in skin
Authors: Na Kwangmin , Lkhagva‐Yondon Enkhmaa , Kim Minha , Lim Yu‐Ree , Shin Eunju , Lee Chong‐Kil , Jeon Myung‐Shin
Published: December 2019

Atopic dermatitis (AD) is a chronic inflammatory skin disease. A hallmark of AD is dry itchy skin that results from defects in the epidermal barrier function. Aloe vera is used widely to promote general health and is administered topically to treat skin conditions such as eczema, burns and wounds. However, effects of A vera on AD were not fully elucidated. In this study, we investigated the oral administration of processed A vera gel (PAG) containing low molecular weight Aloe polysaccharides to treat ovalbumin (OVA)‐induced AD in mice. Oral administration of PAG suppressed total and OVA‐specific IgE production in sera and decreased the epidermal thickness of skin. Numbers of Ki‐67‐positive cells were reduced by PAG treatment. Expression levels of tight junction genes, including those that encode ZO‐1, Claudin‐1 and Claudin‐8, were decreased in AD skin lesions, whereas oral administration of PAG partially restored the expression levels of tight junction genes. In addition, IL‐4 and IL‐17A mRNA transcript levels were reduced in skin lesions after PAG treatment. Taken together, our findings suggest that oral administration of PAG ameliorated AD, normalized tight junction gene expression and suppressed inflammatory cytokines in AD skin.
A novel HLA‐E allele, HLA‐E*01:03:01:05, identified in a healthy Chinese blood donor
Authors: Xu Yun‐Ping , Sun Li‐Yan , Hong Wen‐Xu
Published: December 2019

HLA‐E*01:03:01:05 differs from E*01:01:01:01 by a single nucleotide exchange in nucleotide −33(T‐>C).
External Facilitation as an Evidence‐Based Practice Implementation Strategy During an Antibiotic Stewardship Collaborative in Neonatal Intensive Care Units
Authors: Quinn Jenny M. , Gephart Sheila M. , Davis Mary P.
Published: December 2019

Background

Despite research support, evidence‐based practices (EBPs) are inconsistently implemented throughout the United States. Facilitation is one implementation strategy to speed adoption in clinical settings. Facilitation has not been previously described in the literature as an implementation strategy within neonatal care.

Purpose

The purpose of this study was to categorize and describe essential features of facilitation in the context of implementing an EBP using perspectives elicited from neonatal clinicians and external facilitators (EFs).

Methods

In this qualitative descriptive study, semistructured interviews were conducted with a purposive sample of neonatal clinicians and EFs. Participants shared their experiences related to the strategy of facilitation while implementing an EBP during the California Perinatal Quality Care Antibiotic Stewardship Collaborative. Interviews were transcribed, coded, and analyzed using directed content analysis.

Results

Five categories emerged to address facilitation as an implementation strategy: (a) facilitated change management, (b) unit and organization receptivity, (c) evaluation strategies, (d) supportive culture, and (e) facilitator stewardship.

Linking Evidence to Action

Implementing EBP is complex and multifactorial. Results from this study provide insights into influencing barriers and drivers as experienced by internal and external facilitators, and context factors that impacted the success of implementation.
High Temperature Performance Evaluation and Life Prediction for Titanium Modified Silicone Used in Light-Emitting Diodes Chip Scale Packages
Authors: Yu Si , Wang Zhen , Fan Jiajie , Qian Cheng , Deng Zhentao , Gui Dayong
Published: December 2019

Light-emitting diodes (LED) chip scale packages (CSPs) have been promoted as a new light source with many advantages in smaller package size, lower material and process cost, and better heat dissipation effect. However, as it is exposed in harsh environments such as high temperature, high humidity, and high blue light irradiation, silicone material used in LED CSPs always suffers deterioration, which will seriously affect the LED's reliability and working life. Thus, the preparation of high reliable silicone has practical significance to promote the application of LED CSPs in lighting. In this research, titanium was introduced into the molecular chain of phenyl silicone by using the hydrolysis condensation method. A high temperature aging test was then performed to the prepared silicone before and after modification, and their optical, thermomechanical, and dielectric properties were characterized to evaluate their reliabilities. The results show that: (1) the Arrhenius function with the dielectric property as an aging characterization can be used as a temperature accelerated life model to predict the service life of the prepared silicone and (2) the titanium modified silicone can advance the high temperature stability on optical properties, thermomechanical, and dielectric properties and enhance the life expectancy. The major contributions of this study are to support the improvement of the novel LED CSP packaging materials and processes, and also to provide the technical guidance on the fast, accurate, and cost-effective reliability assessment for high-quality LED light sources.
Effect of Leakage Flow Path Wear on Axial Thrust in Downhole Electrical Submersible Pump Unit
Authors: Patil Abhay , Kasprzyk Marie , Delgado Adolfo , Morrison Gerald
Published: December 2019

Subsea production fluid is quite often characterized by the presence of frac sand, which causes wear within the pump, and alters the performance envelop. One of the design parameters critically affecting reliability is the thrust load generated by an impeller. The change in thrust load due to the erosion of the pump stages is not completely understood, and no relationship exists to foresee these reactive forces due to the complexity involved in predicting the flow characteristics. The purpose of this study is to understand the change in axial thrust due to commonly encountered wear mechanisms across the pump section especially wear across stage clearance seals. Based on in-house erosion testing of a mixed flow pump, three mesh models were built with each representing the pump condition at three different time intervals, namely, 0 h, 52 h, and 117 h of the total test time. The pump numerical models were validated using performance data collected from experimental testing. Axial thrust was found to increase with an increase in wear rate across stage seals. Since the increased clearance causes head degradation as well as an increase in thrust, the relationship of this head degradation is correlated with a change in thrust to further expand the affinity laws.
Hybrid Optical-Flow-Cross-Correlation Method for Particle Image Velocimetry
Authors: Liu Tianshu , Salazar David M. , Fagehi Hassan , Ghazwani Hassan , Montefort Javier , Merati Parviz
Published: December 2019

A hybrid method for particle image velocimetry (PIV) is developed to overcome the limitations of the optical flow method applied to PIV images with large displacements. The main elements of the hybrid method include a cross-correlation scheme for initial estimation, a shifting scheme for generating a shifted image, and an optical flow scheme for obtaining a refined high-resolution velocity field. In addition, a preprocessing scheme is used for correcting the illumination intensity change. The accuracy of the hybrid method is evaluated through simulations in a parametric space in comparison with the typical correlation methods and optical flow method. Further quantitative comparisons are made in PIV measurements in a circular air jet.
Fluid–Structure Interaction Study and Flowrate Prediction Past a Flexible Membrane Using Immersed Boundary Method and Artificial Neural Network Techniques
Authors: Kanchan Mithun , Maniyeri Ranjith
Published: December 2019

Many microfluidics-based applications involve fluid–structure interaction (FSI) of flexible membranes. Thin flexible membranes are now being widely used for mixing enhancement, particle segregation, flowrate control, drug delivery, etc. The FSI simulations related to these applications are challenging to numerically implement. In this direction, techniques like immersed boundary method (IBM) have been successful. In this study, two-dimensional numerical simulation of flexible membrane fixed at two end points in a rectangular channel subjected to uniform fluid flow is carried out at low Reynolds number using a finite volume based IBM. A staggered Cartesian grid system is used and SIMPLE algorithm is used to solve the governing continuity and Navier–Stokes equations. The developed model is validated using the previous research work and numerical simulations are carried out for different parametric test cases. Different membrane mode shapes are observed due to the complex interplay between the hydrodynamics and structural elastic forces. Since the membrane undergoes deformation with respect to inlet fluid conditions, a variation in flowrate past the flexible structure is confirmed. It is found that, by changing the membrane length, bending rigidity, and its initial position in the channel, flowrate can be controlled. Also, for membranes that are placed at the channel midplane undergoing self-excited oscillations, there exists a critical dimensionless membrane length condition L ≥ 1.0 that governs this behavior. Finally, an artificial neural network (ANN) model is developed that successfully predicts flowrate in the channel for different membrane parameters.
Damping-Induced Stability Transitions in Non-Conservative Systems: New Thoughts on an Old Paradox
Authors: Abdullatif Mahmoud , Mukherjee Ranjan , Hellum Aren
Published: December 2019

It is well known that non-conservative systems can become unstable when the level of damping is increased. Systems which become stable at higher levels of damping have also been demonstrated along with the phenomenon of three stability transitions that recently appeared in the literature. This work highlights the role of damping on a two-link system subjected to non-conservative force. The addition of damping can cause the non-conservative systems to become stable, then unstable, then stable again at the same value of the non-conservative forcing. This stability transitions is located by application of the Routh-Hurwitz criterion two times, back-to-back, once for the characteristic polynomial and the second time for the polynomial that guarantees the existence of a second-order auxilliary polynomial in the Routh array.
Aeroservoelastic Modeling and Stability Analysis
Authors: Wang Yu , Tang Wei , Cui Mao , Zhang Gongping
Published: December 2019

It is well known that the elasticity has a great impact on the performance of the slender missile. In this paper, the dynamics of the flexible missile is regarded as a combination of the rigid motion and the elastic vibration. To simplify the modeling, we focus on the influence of the rigid motion on the elastic vibration, instead of completely considering the coupling between rigidity and elasticity. Based on certain assumptions, the longitudinal models of the rigid and elastic missile are derived, and the model of a typical three-loop acceleration autopilot is designed in accordance with the rigid body dynamics. To evaluate the effects of elastic vibration on stability of the closed-loop system, two different sensor placements are simulated in our example. The numerical simulation demonstrates that the bending vibration may deteriorate the tracking performance of autopilot, although it works well for rigid model. In the worst case, the divergent response due to aeroservoelastic instability can be observed, and the unstable response turns into limit-cycle oscillations (LCO) finally for the nonlinear saturation of actuators.
Experimental Study on Performance of a Single-Cylinder Engine Fuelled With Diesel and Vegetable Oil-Diesel Blends
Authors: Banania Amarlo , Quiros Edwin N. , Mercado Jose Gabriel E.
Published: December 2019

Continuous demand for energy in order to provide to an ever-increasing global population calls for use of or integration of other alternative sources of fuel other than fossil fuels. Many countries all over the world use vegetable oils blended with neat diesel as alternative and using these biofuels can help alleviate lessen the emissions releases on the environment as well as the country’s dependency on fossil fuels. In the Philippines Coconut Methyl Ester (CME) is the primary vegetable oil used, however in this study we used four other vegetable oils which are RCO (Refined Corn Oil), RPO (Refine Palm Oil), JFO (Jahtropa Filtered Oil) and JME (Jathropa Methyl Ester) in order to investigate the possibility of their use in diesel engines. A 6.3 kW single-cylinder, four stroke cycle, direct injection engine was used for the study. This kind of engine is typically used in the Philippines for different purposes such as backup power for households, for boats, pumps and for agriculture use. The specific fuel consumption of the biodiesel blends compared to neat diesel fuel ranged from −15% to 15% with RCO and JME having higher SFC and JFO and RPO having lower SFC. Fuel conversion efficiency of the varied from −12% to 12% with JFO and RPO having higher efficiency and RCO and JME having lower efficiency. The power of the varied from −7% to 6% with RPO having lower power output, JFO having higher power output and JME and RCO having similar power output to neat diesel fuel. At full load condasition Neat Diesel Fuel blended with 15% Refined Palm Oil showed the greatest improvement in SFC while Neat Diesel Fuel blended with 10% Jathropa Filtered Oil showed the best power output.
A Study on Urban Heating System Flexibility: Modeling and Evaluation
Authors: Chen Jiaying , Huang Wei , Zhong Wei , Zhou Yi , Lin Xiaojie
Published: December 2019

This study develops a new perspective of analyzing urban heating system (UHS) by taking a looking at the heat transportation flexibility of the system. We proposed the heating system flexibility (HSF) concept to represent UHS’s capability of delivering heat to the substations (and the buildings) under different operation scenarios of valves and pumps. We also give out the corresponding evaluation method. Based on the proposed ideal and its quantification method, we take a real UHS as an example to show the effectiveness of HSF by investigating the impact of heating network topological structure change. When a topological change close to end user is introduced, the average flexibility increases but the median flexibility drops. We find that system-wide topological structure change such as new pipeline does not solve the imbalance of HSF among substations. Overall, the concept of HSF has the potential of being used as an important criterion in the design, operation, and control of future large-scale complex multi-source UHS.
GeoBMS for Better Building Energy Management
Authors: Krishnamurthy Karthik , Singh Pradeep , Sriraman Nikhil
Published: December 2019

Optimization of building energy usage presents an impactful and readily addressable industry opportunity. Commercial building operators have, over the past decade, invested in on-premise Building Management Systems (BMSs) to centrally monitor and operate building sensors and controllers. BMS configurations degrade over time due to changes in building occupancy patterns as well as from ongoing sensor and controller upgrades. Recent studies reveal that an additional 10% energy savings opportunity would be available if optimal BMS configurations were sustained.

Building operators face significant challenges in keeping BMS configurations optimized. The reasons are many. First, most BMSs offer proprietary interfaces that require custom, one-off integrations for remote access. Second, inconsistent BMS data representation makes it hard to aggregate and analyze performance data in order to operate systems with maximum efficiency. Third, BMSs are often designed as single user applications, creating complications to support multiple stakeholders that collectively dictate optimal usage.

We propose a hybrid cloud/on-premise model that addresses the limitations of current, on-premise BMS implementations and incorporates the benefits of new cloud technologies. Our hybrid model employs a cloud-based infrastructure “middle layer” (which we call GeoBMS) that connects the “top layer” of building performance applications with the “bottom layer” of existing brownfield BMS implementations. GeoBMS addresses BMS inaccessibility through virtualization; inconsistent data representation through common cloud data models; and lack of multi-stakeholder access through global authentication.

Through published APIs, GeoBMS enables the creation of innovative building performance applications. Applications use GeoBMS APIs to access previously unavailable on-premise BMS functionality and configuration data. We illustrate using a proof-of-concept application (which we call EnergyOptimize) that optimizes energy consumption for a museum case-example.
A Solid Oxide Fuel Cell-Gas Turbine Hybrid System for a Freight Rail Application
Authors: Ahrend Philipp , Azizi Ali , Brouwer Jacob , Samuelsen G. Scott
Published: December 2019

The simulation of a Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) hybrid system for a locomotive application is presented. Using Matlab Simulink, a 2.8 MW SOFC system was combined with a 500 kW GT and simulated to travel the route from Bakersfield to Mojave in California. Elevation data was imported using the Google API Console and smoothed in order to calculate the dynamic power demand for the SOFC-GT system, assuming 480 tons of freight per 120 ton locomotive traveling at an average speed of 45 mph. The SOFC-GT system model follows this demand without causing a significant disruption to the speed of the locomotive. A lithium-ion battery was included into the system model to improve the net system efficiency and make the operation smooth enough for the highly dynamic route. The overall efficiency along the simulated route has been calculated as 57% operating on partially pre-reformed natural gas fuel.

These results suggest the development of a physical prototype of the simulated system and are very promising for the future of freight rail transportation throughout the US. CO2 and particulate matter emissions are significantly reduced compared to current diesel-electric locomotives and it is also possible to operate the system on hydrogen, i.e., completely emission-free. A techno-economic analysis to assess the economic feasibility of this system is currently being prepared.
Life Cycle Assessment of Greenhouse Gas Emissions: Comparison Between a Cooling Tower and a Geothermal Heat Exchanger for Air Conditioning Applications in Ecuador
Authors: Porras Frank , Ramirez Angel D. , Walter Arnaldo , Soriano Guillermo
Published: December 2019

Cooling towers are widely used to remove heat in buildings with chilled water air conditioning systems. Moreira et al. [1] performed an experimental comparison between a cooling tower (CT) and a geothermal heat exchanger (GHE) in Guayaquil-Ecuador (hot/humid climate) and the results show an advantage of 39% of GHE systems regarding energy efficiency.

This study compares the emissions of greenhouse gases (GHG), considering the results of the research mentioned above and comparing both systems. A life cycle assessment (LCA) approach was used to estimate the GHG emissions, assuming three scenarios for the electricity supply: the electricity generation mix in 2016, the planned electricity generation mix in 2025, and the profile for marginal electricity generation (peak demand).

The estimated reduction of GHG emissions due to the use of GHE systems could be up to 50%. GHEs for building air conditioning applications is a technological option with potential to reduce energy consumption and GHG emissions. However, additional work is necessary to evaluate the complete environmental profile and its cost-effectiveness.
Performance of a Natural Gas Solid Oxide Fuel Cell System With and Without Carbon Capture
Authors: Iyengar Arun K. S. , Koeppel Brian J. , Keairns Dale L. , Woods Mark C. , Hackett Gregory A. , Shultz Travis R.
Published: December 2019

The fuel cell program at the United States Department of Energy (DOE) National Energy Technology Laboratory (NETL) is focused on the development of low-cost, highly efficient, and reliable fossil-fuel-based solid oxide fuel cell (SOFC) power systems that can generate environmentally-friendly electric power with at least 90 percent carbon capture. NETL’s SOFC technology development roadmap is aligned with near-term market opportunities in the distributed generation sector to validate and advance the technology while paving the way for utility-scale natural gas (NG)- and coal-derived synthesis gas-fueled applications via progressively larger system demonstrations. The present study represents a part of a series of system evaluations being carried out at NETL to aid in prioritizing technological advances along research pathways to the realization of utility-scale SOFC systems, a transformational goal of the fuel cell program. In particular, the system performance of utility-scale NG fuel cell (NGFC) systems with and without carbon dioxide (CO2) capture is presented.

The NGFC system analyzed features an external auto-thermal reformer (ATR) feeding the fuel to the SOFC system consisting of planar anode-supported SOFC with separated anode and cathode off-gas streams. In systems with CO2 capture, an air separation unit (ASU) is used to provide the oxygen for the ATR and for the combustion of unutilized fuel in the SOFC anode exhaust along with a CO2 purification unit to provide a nearly pure CO2 stream suitable for transport for usage in enhanced oil recovery operations or for storage in underground saline formations. Remaining thermal energy in the exhaust gases is recovered in a bottoming steam Rankine cycle while supplying any process heat requirements. A reduced order model (ROM) developed at the Pacific Northwest National Laboratory (PNNL) is used to predict the SOFC performance. The ROM, while being computationally effective for system studies, provides other detailed information about the state of the stack, such as the internal temperature gradient, generally not available from simple performance models often used to represent the SOFC. Such additional information can be important in system optimization studies to preclude operation under off-design conditions that can adversely impact overall system reliability. The NGFC system performance was analyzed by varying salient system parameters, including the percent of internal (to the SOFC module) NG reformation — ranging from 0 to 100 percent — fuel utilization, and current density. The impact of advances in underlying SOFC technology on electrical performance was also explored.
Performance Enhancement of Solar Air Conditioners Using Hybrid Heat Rejection System
Authors: Iqbal Abdul Ahad , Al-Alili Ali
Published: December 2019

The performance of air conditioning systems is highly dependent on the environmental conditions of the high pressure side, where heat is rejected to the environment. Air conditioning systems utilize dry cooling systems which often don’t provide adequate cooling during peak cooling periods, or wet cooling systems which consume a lot of water. In this study, a novel hybrid cooling system that can provide both wet and dry cooling was modelled in TRNSYS, and used to provide cooling to closed sorption air conditioning systems. The performance of these systems with the hybrid cooling system was compared to the performance of a standard vapor compression cooling system being cooled by a dry cooling system. The COPsol of the vapor compression cooling system exhibited a decrease of almost 26% during the summer period, whereas the COPsol of the sorption systems increased by around 30%. Similarly, the cooling capacity of the vapor compression cooling system dropped by almost 5%, and for the sorption systems, it increased by around 20% during the summer period.
Study of Different Types of Water Heating Systems - Under Living Lab Conditions
Authors: Dubey Swapnil
Published: December 2019

In Singapore, roughly 20% of the energy consumed by households is used for water heating and almost all the energy consumed by conventional electric water heaters. One of the significant potential energy saving opportunities lies in using energy-efficient water heating appliances. Recently, there has been a move towards energy-saving design and the use of natural refrigerants over fluorocarbons. Unlike conventional electric storage water heaters, which use electricity to heat water directly, heat pump storage water heaters use electricity only to operate a pump that circulates refrigerants around the system. This refrigerant collects heat from the surrounding atmosphere and transfers it to the water. CO2 heat pumps have low global warming potential when compared to other refrigerants based heat pumps, has zero ozone depletion potential, inexpensive, non-flammable, generate high temperature. In this project, a comparative analysis of three different water heater types has been presented based on real-time usage and living-lab conditions under the tropical climate of Singapore. These three types are:

1. Electrical heater storage type

2. Hybrid heat pump with auxiliary electrical heating water heater

3. CO2 heat pump water heater without auxiliary heating

Study found significant energy saving using CO2 heat pump compared to other water heating system and also better for environment.