bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identifying Uncertainties in Diesel Spray Rate-of-Momentum Transients Under Elevated Back Pressure
Authors: Falcone John A. , Knox Benjamin W. , Genzale Caroline L. 
Published: January 2016

Rate-of-momentum measurements of transient fuel sprays are valuable for improving current combustion and emission strategies. This data provides boundary conditions for engine computational fluid dynamic (CFD) simulations and provides insight into the transient mixing characteristics of the spray prior to and during combustion. Previous researchers have quantified the rate-of-momentum of transient sprays using the impingement technique, but uncertainties remain in relating the impingement force to the injected fuel momentum at the nozzle exit. Rate-of-momentum measurements are typically performed by directing a spray onto the face of a calibrated transducer in close proximity to the nozzle. The measured impingement force is then used to quantify the rate-of-momentum at the nozzle orifice exit with the aid of a simplified control volume analysis. However, under elevated back pressures, additional terms in the control volume analysis are no longer negligible. Other non-idealities, such as non-orthogonal droplet impingement outcomes and transient mass accumulation in the control volume, can also contribute to errors in the simplified analysis.
This paper investigates the impact of non-idealities in impingement-based rate-of-momentum measurements on the quantified fuel injection rate. In specific, we compare the measured rate-of-momentum under back pressure and atmospheric pressure using two different transducers to quantify uncertainties that can arise under back pressure conditions. Uncertainties associated with transient mass accumulation and non-orthogonal spray deflection are also investigated. We found that back pressure affected both the start and end of injection when compared to atmospheric pressure. Under back pressure, there was a lengthened apparent start-of-injection transient, which likely results from a low pressure toroidal vortex occurring at the head of the spray. In addition, there was a longer apparent closing transient, which is likely a result of residual pressure distribution after the end-of-injection. No evidence of transient mass accumulation was observed for the injectors used in this study. Lastly, the transient spray was observed to deflect non-orthogonally from the impact point on the transducer instead of remaining parallel to the transducer face after initial impact. This deflection of the spray leads to uncertainties when quantifying the rate-of-momentum, where the apparent rate-of-momentum could be larger than the actual value.
Experimental Investigation of a Diesel Engine Fuelled With Acetone-Butanol-Ethanol/Diesel Blends
Authors: Lee Timothy H. , Lin Yilu , Nithyanandan Karthik , Zhang Jiaxiang , Li Yuqiang , Yang Jikai , Hansen Alan C. , Lee Chia-fon F. 
Published: January 2016

The performance and emissions of Acetone-Butanol-Ethanol (ABE)/diesel mixtures in an AVL 5402 single cylinder diesel research engine under various engine operating conditions were investigated in this study. The experiments were conducted at three different speeds (1200, 1500, and 2000 RPM) and different injection quantities (loads) (15, 20, and 25 mg/cycle).
The fuels tested in these experiments were pure diesel, ABE10, and ABE20. The acetone-butanol-ethanol (ABE) was blended in a 3:6:1 ratio. ABE10 and ABE20 consist of 10% acetone-butanol-ethanol mixture and 90% diesel by volume and 20% ABE and 80% diesel by volume respectively.
The results showed a promising future for ABE-diesel mixture as an alternative transportation fuel. There was improved thermal efficiency even with relatively small ABE blending ratios and a slight reduction in power output due to the lower energy density. There was an overall retarded combustion phasing, including longer ignition delay time, retarded CA50 timing, peak pressure timing and end of combustion timing. Accelerated heat release during CA10∼CA50 indicates a higher degree of premixed combustion. Overall soot emissions were lower and NOx emissions were higher for ABE-containing fuels at same load and timing conditions. Tuning injection timing would be helpful for the reduction of NOx to a degree that is even lower than that of diesel.
With proper tuning of injection quantity and injection timing, adopting ABE-diesel mixtures has the potential of improving efficiency and reducing emissions at the same time. Considering the low cost of ABE production compared to other kinds of bio-fuels, ABE could become a possible alternative to the current fuel additives.
Fast Computation of Combustion Phasing and its Influence on Classifying Random or Deterministic Patterns
Authors: Lian Huan , Martz Jason , Prakash Niket , Stefanopoulou Anna 
Published: January 2016

The classification between a sequence of highly variable combustion events that have an underlying deterministic pattern and a sequence of combustion events with similar level of variability but random characteristics is important for control of combustion phasing. In the case of high cyclic variation (CV) with underlying deterministic patterns, it is possible to apply closed loop combustion control on a cyclic-basis with a fixed mean value, such as injection timing in homogeneous charge compression ignition (HCCI) or spark timing in spark ignition (SI) applications, to contract the CV. In the case of a random distribution, the high CV can be avoided by shifting operating conditions away from the unstable region via advancing or retarding the injection timing or the spark timing in the mean-sense.
Therefore, the focus of this paper is on the various methods of computing CA50 for analysing and classifying cycle-to-cycle variability. The assumptions made to establish fast and possibly on-line methods can alter the distribution of the calculated parameters from cycle-to-cycle, possibly leading to incorrect pattern interpretation and improper control action.
Finally, we apply a statistical technique named “permutation entropy” for the first time on classifying combustion patterns in HCCI and SI engine for varying operating condition. Then the various fast methods for computing CA50 feed the two statistical methods, permutation and the Shannon entropy, and their differences and similarities are highlighted.
Approach to Risk Management for the Hydrocarbon-Transport Infrastructure With Regard to Climate Change
Authors: Zapata Posada Dario , Aristizábal Ceballos Jaime Hernán , Chaves Agudelo Julián Fernando , Pardo Romero Milton Eduardo 
Published: January 2016

Planet Earth has recently witnessed a change in the behavior of climate variables (including temperature, rainfall, etc.), primarily attributed to global warming. This climate change is a threat that is materializing and has affected elements of the infrastructure, ecosystems, and environmental conditions worldwide, as well as the National Development Plans [“Planes Nacionales de Desarrollo”].
The hydrocarbon-transport infrastructure in Colombia has not escaped the effects of climate variability. Therefore, a strategy must be devised to manage the risk and to adapt these systems in the light of potential harmful effects, and also to supplement or improve the mitigation measures for the effects generated by the oil industry through its operations.
Climate disturbances lead to an increase in the likelihood of landslides, wildfires, floods, avalanches, and other natural hazards.
The major climate changes that have been identified and that may affect hydrocarbon-transfer systems in Colombia are the following ones:
• A gradual increase in temperature.
• Changes in the patterns and amounts of rainfall.
• A rise in sea level.
• An increase in the severity and frequency of extreme weather events.
The strategy for adapting the hydrocarbon-transport systems in light of climate change focuses primarily on the following points:
1. Acquiring more knowledge about the climatic changes that are expected to occur in Colombia, including the change in the major climatic variables and their georeferencing.
2. Diagnosing the transport systems and their spatial correlation with future climate scenarios.
3. Identifying the industries or elements of the infrastructure that are most vulnerable to the expected climatic changes.
4. Proposing measures that will add strength and/or resilience, so that the elements of the system can resist the effects of climate change, or overcome them within a short period of time, without affecting the Business.
5. Prioritizing the interventions to be performed at sites that are critical to the Business.
6. Monitoring and tracking the climatic variables in order to adjust the susceptibility models in light of the major impacts (e.g., landslides).
The primary goal of this paper is to outline the initiative that has been proposed by the Technical Asset Management Bureau [“Gerencia Técnica de Activos”] (GTA) of Ecopetrol’s Office of the Vice President for Transportation and Logistics [“Vicepresidencia de Transporte y Logística”] (VIT Ecopetrol) in order to adapt the currently operating transport systems so that they can deal with climate change, while ensuring their healthful and safe operation, in compliance with the applicable technical legal requirements. Another goal of this paper is to highlight the advances that have been made by the GTA in the procurement, compilation, analysis, and use of climate information and geotechnical data as basic elements of risk management.
Resource Optimization for Geotechnical Protective Structures on Rights-of-Way
Authors: Barrera Nidia , Vásquez German , Gil José Vicente Amórtegui , Castañeda Bernardo , García Mauricio , Ramírez Yuddy 
Published: January 2016

An analysis was performed of the charts that are traditionally employed in the determination of the separation of geotechnical protective structures on rights-of-way, such as cut-offs and trench barriers. An analysis was performed for the specific study area, with information from the existing weather and rainfall stations, which made it possible to characterize more accurately the rainfall figure required for curve fitting. Furthermore, knowledge of the soils in the area made it possible to classify them in terms of erodability. This classification was used to establish curves that better reflect the actual conditions of the soils of the rights-of-way. A conceptual analysis was performed of the need for the implementation of these structures in order to control erosion along the rights-of-way. This analysis made it possible to propose changes in the materials specification, in order to optimize costs during construction.
As a supplement to the study of the protective structures for the rights-of-way, the dimensions of the trench for the installation of the pipelines was analyzed. This analysis included a comparison of the actual construction dimensions of the trench against the dimensions recommended by international standards and the ones contained in the international literature. Certain Colombian projects that supplement the analysis are also cited. The foregoing findings were used in the preparation of certain recommendations regarding the reduction of the dimensions of the trench for certain specific technical, social, and environmental conditions.
Last, based on the analyses that were performed, the study proposes certain changes in the operator’s current standards, primarily regarding items such as cut-offs, trench barriers, and the dimensions of the trench. These changes will lead to a reduction in the construction costs of the geotechnical protective structures for hydrocarbon-pipeline rights-of-way. These items are typical, because the pipelines in question are located predominantly on foothill plains.
The Application of Piezo Based Subsystems for Improved Machining Processes
Authors: Drossel Welf-Guntram , Bucht André , Kunze Holger , Pagel Kenny 
Published: January 2016

Due to their very high applicable forces, frequencies and their stiffness, piezoceramics are feasible to serve as integrated actuators in machines. The application of piezo based components in production engineering was subject of plenty of investigations in the past. That focuses primarily on systems for condition monitoring, structural vibration reduction or chatter prevention. However there are currently also few approaches that aim to use piezo actuators for directly induced vibrations for improved machining processes.
In this paper we present an overview of such systems, their parameters and the technological background. Known approaches will be classified and divided into groups considering their working principles, actuator performance and application technology. Ultra sonic machining (USM) for example is a comparatively old approach which applies ultrasonic vibrations of a sonotrode to an abrasive slurry for machining hard, brittle and nonconductive material. Vibration assisted machining (VAM) systems are rather different. They are characterized by low stroke, uncontrolled but highly frequent resonant vibrations of the tool to achieve enhanced chipping behavior or generally enable to machine certain hard materials. Fast Tool servo (FTS) systems are even more complex. They apply an overlaid controlled movement of the cutting edge to manufacture microstructures or possess to manufacture complex geometries like non circular bores or turned parts.
Selected systems will be presented in detail showing their design approach, actuator parameters, control considerations and measurement data of manufactured parts. These will be for instance an ultrasonic deep hole drilling tool, a form honing system, an active spindle mounting for micro contouring and a piezo based machine table for manufacturing non circular bores in small workpieces. Summarized the existing systems will be compared considering their advantages and eventual hindrances. Beyond that the outlook will show problems, which need to be solved in the future to enable piezo assisted machining systems a more comprehensive application in manufacturing.
SMA-Based Hydraulic Switching Valve
Authors: Nalbach Sophie , Motzki Paul , Seelecke Stefan 
Published: January 2016

Hydraulic switching valves are vital components commonly used in hydraulic applications. In a simple configuration, the valve has two states, open and closed. A spring pushes a spool into its first position and typically an electro-magnetic actuator working against the spring force is used to pull the spool into its second position.
Shape Memory Alloys (SMA’s) are known as actuators with very high energy density. This fact allows for the construction of very light weight and compact systems. The focus of this work is to replace the traditionally used electro-magnetic actuator in a hydraulic switching valve with an SMA wire actuator. This will allow for a reduction in the construction space and weight of the switching valve.
This work begins with an evaluation of the force and stroke requirements of a commercially available magnetic valve. Based on this information a new valve design using SMA wires is constructed to meet the same performance requirements. Once designed and fabricated, the SMA based valve is evaluated with respect to force and stroke. Finally both valves are arranged with other hydraulic components in a test station for direct performance comparison. The results concerning the hydraulic parameters like pressure and flow rate are compared to the conventional valve. In conclusion, the experimental results are displayed and an outlook on future work and possible application scenarios is given.
Structural Health Monitoring of Pipelines for Environment Pollution Mitigation
Authors: Felli Ferdinando , Paolozzi Antonio , Vendittozzi Cristian , Paris Claudio , Asanuma Hiroshi , De Canio Gerardo , Mongelli Marialuisa , Colucci Alessandro 
Published: January 2016

Oil and gas infrastructures may be exposed to landslides, earthquakes, corrosion and fatigue, and to damage from thefts or vandalism, leading to leakage and failure with serious economic and ecologic consequences. For this reason, an increasing interest in applied research on monitoring and protecting pipelines (for fuel, oil and natural gas transportation) arises. Aimed at the mitigation of catastrophic effects of human and natural damage, the present paper proposes a smart real-time Structural Health Monitoring (SHM) system capable to control structural integrity continuously, focusing on the issue of spillage for thefts of fuels which are not detectable, in real-time, by the existing monitoring systems.
The system consists of a smart-pipeline containing a health monitoring integrated measurement chain, i.e. an enhanced Fiber Bragg Gratings-based fiber optics neural network on the pipes, for displacement and acceleration monitoring (gathering many other different measurements such as: ground motion, permanent ground displacement, pipeline temperature, pipeline deformation, leakage, etc.).
Specifically, the ability to measure these characteristics at hundreds of points along a single fiber and the great accuracy of each point of measure, are particularly interesting for the monitoring of structures such as pipelines in order to detect hazardous and unauthorized intrusion and damage.
Uncertainty Quantification of Energy Harvesting Systems Using Method of Quadratures and Maximum Entropy Principle
Authors: Nanda Aditya , Karami M. Amin , Singla Puneet 
Published: January 2016

This paper uses the method of Quadratures in conjunction with the Maximum Entropy principle to investigate the effect of parametric uncertainties on the mean power output and root mean square deflection of piezoelectric vibrational energy harvesting systems. Uncertainty in parameters of harvesters could arise from insufficient manufacturing controls or change in material properties over time. We investigate bimorph based harvesters that transduce ambient vibrations to electricity via the piezoelectric effect. Three varieties of energy harvesters — Linear, Nonlinear monostable and Nonlinear bistable are considered in this research.
This analysis quantitatively shows the probability density function for the mean power and root mean square deflection as a function of the probability densities of the excitation frequency, excitation amplitude, initial deflection of the bimorph and magnet gap of the energy harvester. The method of Quadratures is used for numerically integrating functions by propagating weighted points from the domain and evaluating the integral as a weighted sum of the function values. In this paper, the method of Quadratures is used for evaluating central moments of the distributions of rms deflection and mean harvested power and, then, in conjunction with the principle of Maximum Entropy (MaxEnt) an optimal density function is obtained which maximizes the entropy and satisfies the moment constraints. The The computed nonlinear density functions are validated against Monte Carlo simulations thereby demonstrating the efficiency of the approach. Further, the Maximum Entropy principle is widely applicable to uncertainty quantification of a wide range of dynamic systems.
A pilot, quasi-experimental, mixed methods investigation into the efficacy of a group psychotherapy intervention for caregivers of outpatients with cancer: the COPE study protocol
Authors: Mahendran Rathi , Tan Joyce Yi Siang , Griva Konstadina , Lim Haikel Asyraf , Ng Hui Ying , Chua Joanne , Lim Siew Eng , Kua Ee Heok 
Published: January 2016

IntroductionDespite the rising trend of cancer prevalence and increase in family caregiving, little attention has been paid to the efficacy of psychosocial interventions among Asian caregiver samples, particularly support groups, given the benefits that have been shown in studies on Western populations. This trial aims to evaluate the effectiveness of a pilot 4-week group psychotherapy for Singaporean family caregivers of patients receiving outpatient care.Methods and analysisFacilitated by a clinical psychologist, this intervention is primarily based on the brief integrative psychological therapy with a supportive-expressive intent. Participants will be recruited while they are accompanying their care recipients for outpatient consultations. Since this is a pilot study, a sample size of 120 participants is targeted on the basis of sample sizes of previous studies. The study adopts a quasi-experimental design, as participants are assigned the intervention or control arms based on their availability to attend the intervention. A mixed methods approach is used to evaluate the outcomes of the intervention. A self-administered battery of tests is completed at four time points: baseline, postintervention and follow-up at 1-month and 2-month postinterventions; semi-structured interviews are conducted at baseline and post-intervention. Primary outcomes are quality of life and anxious and depressive symptoms; secondary outcomes are stress and basic psychological needs. Analysis using analysis of covariance would be conducted to determine the effectiveness of the intervention.Ethics and disseminationThis study protocol has ethics approval from the National Healthcare Group Domain Specific Review Board (NHG DSRB Ref: 2013/00662). Written informed consent is obtained from every participant. Results will be disseminated through journals and conferences, and will be particularly relevant for clinicians intending to implement similar support groups to address the psychosocial concerns of caregivers, as well as for researchers seeking to refine the structure and evaluate the effectiveness of such programmes.Trial registration numberCurrent Controlled TrialsNCT02120183(https://clinicaltrials.gov/show/NCT02120183)
Mesh fixation methods in open inguinal hernia repair: a protocol for network meta-analysis and trial sequential analysis of randomised controlled trials
Authors: Ge Long , Tian Jin-hui , Li Lun , Wang Quan , Yang Ke-hu 
Published: January 2016

IntroductionRandomised clinical trials (RCTs) have been used to compare and evaluate different types of mesh fixation usually employed to repair open inguinal hernia. However, there is no consensus among surgeons on the best type of mesh fixation method to obtain optimal results. The choice often depends on surgeons’ personal preference. This study aims to compare different types of mesh fixation methods to repair open inguinal hernias and their role in the incidences of chronic groin pain, risk of hernia recurrence, complications, operative time, length of hospital stay and postoperative pain, using Bayesian network meta-analysis and trial sequential analysis of RCTs.Methods and analysisA systematic search will be performed using PubMed, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Chinese Biomedical Literature Database (CBM) and Chinese Journal Full-text Database, to include RCTs of different mesh fixation methods (or fixation vs no fixation) during open inguinal hernia repair. The risk of bias in included RCTs will be evaluated according to the Cochrane Handbook V.5.1.0. Standard pairwise meta-analysis, trial sequential analysis and Bayesian network meta-analysis will be performed to compare the efficacy of different mesh fixation methods.Ethics and disseminationEthical approval and patient consent are not required since this study is a meta-analysis based on published studies. The results of this network meta-analysis and trial sequential analysis will be submitted to a peer-reviewed journal for publication.Protocol registration numberPROSPERO CRD42015023758.