bluuebunny/crossref_metadata_2025 huggingface dataset:
The Use and Performance of Household Refrigerators: A Review
Authors: James Christian , Onarinde Bukola A. , James Stephen J.
Published: December 2016

The domestic refrigerator is now a common household device with very few households in the developed world not possessing 1, or more, for the storage of chilled foods. Domestic storage is the last, and in many respects the most important, link in the food chill chain. Inadequate domestic refrigeration or cooling is frequently cited as a factor in incidents of food poisoning. The authors reviewed the temperature performance of refrigerators in 2008. This new review builds on that review, covering studies that have been published since (and those that were unfortunately missed in the first review), and also seeks to put this important stage of the food cold chain in its context. It is clear from the published data that many refrigerators throughout the world are running at higher than recommended temperatures. It is also clear that, despite improvements in energy use, the temperature performance and use of refrigerators have not changed significantly in the last 40 or so years. Many householders still remain unaware of the recommended refrigeration temperature range, how to ensure that the correct refrigeration temperature range is achieved, the importance of monitoring that it is being maintained, and the potential hazards of temperature abuse.
Use of Autopsy to Determine Live or Stillbirth: New Approaches in Decision‐support Systems
Authors: Yilmaz Riza , Erkaymaz Okan , Kara Erdogan , Ergen Kivanc
Published: December 2016

Fetal deaths are important cases for forensic medicine, as well as for criminal and civil law. From a legal perspective, the determination of whether a deceased infant was stillborn is a difficult process. Such a determination is generally made during autopsy; however, no standardized procedures for this determination exist. Therefore, new facilitative approaches are needed. In this study, three new support systems based on 10 autopsy parameters were tested for their ability to correctly determine whether deceased infants were alive or stillborn. Performances were analyzed and compared with one another. The artificial neural networks and radial basis function network models had 90% accuracy (the highest among the models tested), 100% sensitivity, and 83.3% specificity. Thus, the models presented here provide additional insights for future studies concerning infant autopsies.
Australopapuan leaf beetle diversity: the contributions of hosts plants and geography
Authors: Reid Chris AM
Published: December 2016

The diversity of Chrysomelidae (Coleoptera) in Australia and New Guinea (Australopapua) is reviewed. There are 3100 described species in 244 genera, with a further 2300 species to be described or confirmed. Approximately 11.6% of the world species of Chrysomelidae are found in Australopapua. Among the larger subfamilies, there is a relative dearth of Bruchinae, Cassidinae and Criocerinae and a relative abundance of Chrysomelinae, Cryptocephalinae and Eumolpinae. In the smaller subfamilies, Lamprosomatinae and Synetinae are absent, whereas Sagrinae and Spilopyrinae are strongly represented. Endemicity at generic level is high, exceeding 30% in all subfamilies, except Donaciinae (one species), and exceeding 50% in Chrysomelinae, Cryptocephalinae, Eumolpinae, Sagrinae and Spilopyrinae. The most diverse and ecologically dominant plant orders host the most chrysomelid genera (39 genera on Myrtales, 34 on Fabales, 15 genera on both orders), but many major plant orders in the region, such as Ericales, are almost ignored. Processes contributing to the diversity of Chrysomelidae in Australopapua are discussed, particularly co‐speciation, co‐evolution, dispersal and vicariance.
Placing researcher identifications: labs, offices and homes in the PhD
Authors: Dowling Robyn , Mantai Lilia
Published: December 2016

Recent and ongoing changes in university structures and desires, as well as alterations in doctoral education, are shaping new spatialities and temporalities of academic work and identities. This paper considers the spatialities of one set of researcher identities – those undertaking PhD degrees – and specifically explores the material and socio‐cultural affordances of the sites in which research is practised. Based on a qualitative study (interviews with 30 PhD students and focus groups with 34 students) at two Australian metropolitan and research‐intensive universities, we find students associate different forms of researcher identities with the different spaces of research work. In particular, the university campus and specifically the office and/or laboratory are sites where research is approached as a form of work, and identification as both worker and researcher. Notably, social connections and the power relations of the campus are woven through these identifications. Home, in contrast, can serve as a place of respite or a quiet space to think, but more often disrupts identifications as researcher or emergent academic. This research suggests the need first, to recognise the significance of a physical workspace on campus for developing researchers and second, for a more nuanced consideration of the notion of a neoliberalised university.
Peer assessment in MOOCs: The relationship between peer reviewers’ ability and authors’ essay performance
Authors: Huisman Bart , Admiraal Wilfried , Pilli Olga , van de Ven Maarten , Saab Nadira
Published: December 2016

In a relatively short period of time, massive open online courses (MOOCs) have become a considerable topic of research and debate, and the number of available MOOCs is rapidly growing. Along with issues of formal recognition and accreditation, this growth in the number of MOOCs being developed increases the relevance of assessment quality. Within the context of a typical xMOOC, the current study focuses on peer assessment of essay assignments. In the literature, two contradicting theoretical arguments can be found: that learners should be matched with same‐ability peers (homogeneously) versus that students should be matched with different‐ability peers (heterogeneously). Considering these arguments, the relationship between peer reviewers’ ability and authors’ essay performance is explored. Results indicate that peer reviewers’ ability is positively related to authors’ essay performance. Moreover, this relationship is only established for intermediate and high ability authors; essay performance of lower ability authors appeared not to be related to the ability of their reviewing peers. Results are discussed in relation to the matching of learners and instructional design of peer assessment in MOOCs.
Elevated fetal haemoglobin is a predictor of better outcome in MDS/AML patients receiving 5‐aza‐2′‐deoxycytidine (Decitabine)
Authors: Lübbert Michael , Ihorst Gabriele , Sander Philipp N. , Bogatyreva Ljudmila , Becker Heiko , Wijermans Pierre W. , Suciu Stefan , Bissé Emmanuel , Claus Rainer
Published: December 2016

Although azanucleoside DNA‐hypomethylating agents (HMAs) are routinely used for the treatment of myelodysplastic syndrome/acute myeloid leukaemia (MDS/AML), very few outcome predictors have been established. Expression of the β‐like globin gene locus is tightly regulated by DNA methylation, is HMA‐sensitive in vitro, and fetal haemoglobin (HbF) expression is under study as a potential biomarker for response of MDS patients to azacitidine. We determined HbF expression in 16 MDS and 36 AML patients receiving decitabine (DAC). Pre‐treatment HbF was already elevated (>1·0% of total haemoglobin) in 7/16 and 12/36 patients, and HbF was induced by DAC in 81%/54% of MDS/AML patients, respectively. Elevated pre‐treatment HbF was associated with longer median overall survival (OS): 26·6 vs. 8·6 months for MDS (hazard ratio [HR] 8·56, 95% confidence interval [CI] 1·74–42·49, P = 0·008, with similarly longer progression‐free and AML‐free survival), and 10·0 vs. 2·9 months OS for AML (HR 3·01, 95% CI 1·26–7·22, P = 0·014). In a multivariate analysis, the prognostic value of HbF was retained. Time‐dependent Cox models revealed that the prognostic value of treatment‐induced HbF induction was inferior to that of pre‐treatment HbF. In conclusion, we provide first evidence for in vivo HbF induction by DAC in MDS/AML, and demonstrate prognostic value of elevated pre‐treatment HbF, warranting prospective, randomized studies.
Sialyltransferase ST3GAL6 mediates the effect of microRNA‐26a on cell growth, migration, and invasion in hepatocellular carcinoma through the protein kinase B/mammalian target of rapamycin pathway
Authors: Sun Mingming , Zhao Xuzi , Liang Leilei , Pan Xufeng , Lv Hao , Zhao Yongfu
Published: December 2016

Aberrant sialylation profiles on the cell surface have been recognized for their potential diagnostic value in identifying the regulation of tumor properties in several cancers, including hepatocellular carcinoma (HCC). Recently, increasing evidence has suggested that the deregulation of microRNA (miRNA) is a common feature in human cancers. In this study, we found obvious upregulation of sialyltransferase ST3GAL6 both in HCC cell lines and in tissue samples. The altered expression of ST3GAL6 was found to correlate with cell proliferation, migration, and invasion ability in HCC. Further investigation showed that miR‐26a negatively regulated ST3GAL6, inducing the suppression of cell proliferation, migration, and invasion in vitro. Moreover, we identified the protein kinase B/mammalian target of rapamycin (Akt/mTOR) pathway as the target of ST3GAL6 based on Western blot analysis. Analysis of a xenograft mouse model showed that miR‐26a significantly reduced tumor growth by suppressing activation of the Akt/mTOR pathway by directly targeting ST3GAL6. In conclusion, these data indicate that ST3GAL6 promotes cell growth, migration, and invasion and mediates the effect of miR‐26a through the Akt/mTOR signaling pathway in HCC.
Neutrophil activation during acute human anaphylaxis: analysis of MPO and sCD62L
Authors: Francis A. , Bosio E. , Stone S. F. , Fatovich D. M. , Arendts G. , Nagree Y. , Macdonald S. P. J. , Mitenko H. , Rajee M. , Burrows S. , Brown S. G. A.
Published: December 2016

Background

The mechanisms involved in the amplification of the mast cell response during anaphylaxis are unclear. Mouse models of anaphylaxis demonstrate the critical involvement of neutrophils. These innate immune cells are highly abundant in peripheral blood and can be rapidly activated to trigger both local and systemic inflammation.

Objective

To investigate neutrophil activation in peripheral blood during acute human anaphylaxis.

Methods

Patients presenting to the emergency department with anaphylaxis underwent blood sampling upon enrolment and at up to three subsequent time‐points. Traditional anaphylaxis biomarkers, histamine and mast cell tryptase, were measured by ELISA and ImmunoCAP, respectively. Plasma myeloperoxidase concentrations were measured by ELISA, serum soluble CD62L concentrations by cytometric bead array, and both compared to healthy controls.

Results

In 72 patients, 37 (51%) had severe anaphylaxis, 33 (60%) were histamine positive, and 47 (70%) were mast cell tryptase positive. At enrolment, myeloperoxidase concentrations were 2.9‐ (95% CI: 1.3, 6.5) and 5.0‐ (95% CI: 2.4, 10.5) fold higher in moderate and severe patients, respectively, compared with healthy controls, and remained stable over the first 5 h following symptom onset. At enrolment, soluble CD62L was 29% (95% CI: 19, 38) and 31% (95% CI: 22, 40) lower in moderate and severe patients, respectively, than healthy controls, and was stable over the first 5 h. There were no associations between myeloperoxidase or soluble CD62L concentrations and either histamine or mast cell tryptase concentrations.

Conclusions and Clinical Relevance

These results provide compelling evidence for the involvement of neutrophils during acute human anaphylaxis, suggesting they are activated early in the reaction, regardless of mast cell activation. This important finding increases our understanding of the basic mechanisms of anaphylaxis, a necessary precursor to improving treatment and prevention.
The quality of compliance: investigating fishers’ responses towards regulation and authorities
Authors: Boonstra Wiebren J , Birnbaum Simon , Björkvik Emma
Published: December 2016

A substantial amount of scientific effort goes into understanding and measuring compliance in fisheries. Understanding why, how and when fishers follow or violate rules is crucial for designing effective fishery policies that can halt overfishing. Non‐compliance was initially explained almost exclusively with reference to economic and self‐interested motivations. More recently, however, most explanations involve a combination of economic, social, political and environmental factors. Despite this recent development towards more holistic explanations, many scientists continue to frame the issue in binary terms: fishers either follow rules, or they don't. In this article we challenge this binary interpretation and focus attention on the diversity of fishers’ dispositions and perceptions that underpin compliant behaviour. To this aim we construct a typology of fishers’ responses towards regulation and authorities, thereby developing conceptual tools to understand different motivations and attitudes that underlie compliance outcomes. For this purpose, we identify the motivational postures of ‘creativity’ and ‘reluctance’, and then highlight their empirical relevance with an interview study of Swedish fishers. Reasons for studying the quality and diversity of fishers’ motivations and responses are not purely academic. Conceptualizing and observing the quality of compliance can help policymakers and managers gauge and anticipate the potentiality of non‐compliant fishing practices that may threaten the resilience of marine ecosystems.
Herpes simplex infection simulating Richter transformation: a series of four cases and review of the literature
Authors: Salem Alireza , Loghavi Sanam , Khoury Joseph D , Agbay Rose Lou Marie C , Jorgensen Jeffrey L , Medeiros L Jeffrey
Published: December 2016

Aims

Richter transformation (RT) occurs in 5–10% of patients with chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL), and is associated with a poor outcome. The histological manifestations of RT are variable, and include an increase in the proportion of prolymphocytes, immunoblasts, and other pleomorphic cells, along with an increased proliferation rate and often necrosis. Rarely, superimposed herpes simplex virus (HSV) infection involving lymph nodes in patients with CLL/SLL may mimic RT clinically and histologically. In this study, we describe four cases of CLL/SLL with superimposed HSV lymphadenitis, and we review the literature.

Methods and results

We describe the clinicopathological and immunophenotypic findings of four cases of CLL/SLL with superimposed HSV infection. The patients presented with B‐type symptoms, and laboratory and imaging findings suggested progression of lymphoma. Histologically, there were geographical areas of necrosis and increased numbers of prolymphocytes and immunoblasts, in some areas forming sheets, with increased mitotic figures and a high proliferation (Ki67) rate. However, the necrotic regions were associated with acute inflammatory cells and larger cells, mostly necrotic, showing viral cytopathic effects. Therapy with antiviral agents resulted in improvement of clinical symptoms and laboratory and imaging findings. Additionally, we identified 11 cases of CLL/SLL with superimposed HSV infection described in the English‐language literature, and integrated the cases that we report here into this wider context.

Conclusions

Herpes simplex virus infection of lymph nodes in patients with CLL/SLL results in clinicopathological and radiological findings that may mimic RT. It is essential to refrain from misclassifying these cases as RT, as patients can respond remarkably well to antiviral therapy.
The interaction of sleep and amyloid deposition on cognitive performance
Authors: Molano Jennifer R. V. , Roe Catherine M. , Ju Yo‐El S.
Published: December 2016

Sleep difficulties are emerging as a risk factor for dementia. This study examined the effect of sleep and amyloid deposition on cognitive performance in cognitively normal adults. Sleep efficiency was determined by actigraphy. Cerebrospinal fluid Aβ42 levels <500 pg mL−1, indicating amyloid deposition, was present in 23 participants. Psychometric tests included the Free and Cued Selective Reminding Test, Trail Making Test A and B, Animal Fluency, Letter Number Sequencing, and the Mini Mental State Examination. The interaction term of sleep efficiency and amyloid deposition status was a significant predictor of memory performance as measured by total Selective Reminding Test scores. While Trail Making Test B performance was worse in those with amyloid deposition, sleep measures did not have an additive effect. In this study, amyloid deposition was associated with worse cognitive performance, and poor sleep efficiency specifically modified the effect of amyloid deposition on memory performance.
Comprehensive identification and clustering of CLV3/ESR‐related (CLE) genes in plants finds groups with potentially shared function
Authors: Goad David M. , Zhu Chuanmei , Kellogg Elizabeth A.
Published: December 2016

CLV3/ESR (CLE) proteins are important signaling peptides in plants. The short CLE peptide (12–13 amino acids) is cleaved from a larger pre‐propeptide and functions as an extracellular ligand. The CLE family is large and has resisted attempts at classification because the CLE domain is too short for reliable phylogenetic analysis and the pre‐propeptide is too variable.

We used a model‐based search for CLE domains from 57 plant genomes and used the entire pre‐propeptide for comprehensive clustering analysis.

In total, 1628 CLE genes were identified in land plants, with none recognizable from green algae. These CLEs form 12 groups within which CLE domains are largely conserved and pre‐propeptides can be aligned. Most clusters contain sequences from monocots, eudicots and Amborella trichopoda, with sequences from Picea abies, Selaginella moellendorffii and Physcomitrella patens scattered in some clusters. We easily identified previously known clusters involved in vascular differentiation and nodulation. In addition, we found a number of discrete groups whose function remains poorly characterized. Available data indicate that CLE proteins within a cluster are likely to share function, whereas those from different clusters play at least partially different roles.

Our analysis provides a foundation for future evolutionary and functional studies.
Severe asthma: Current management, targeted therapies and future directions—A roundtable report
Authors: McDonald Vanessa M. , Maltby Steven , Reddel Helen K. , King Gregory G. , Wark Peter A.B. , Smith Lorraine , Upham John W. , James Alan L. , Marks Guy B. , Gibson Peter G.
Published: December 2016

ABSTRACT

Asthma is a chronic respiratory disease characterized by respiratory symptoms, airway inflammation, airway obstruction and airway hyper‐responsiveness. Asthma is common and directly affects 10% of Australians, 1–5% of adults in Asia and 300 million people worldwide. It is a heterogeneous disorder with many clinical, molecular, biological and pathophysiological phenotypes. Current management strategies successfully treat the majority of patients with asthma who have access to them. However, there is a subset of an estimated 5–10% of patients with asthma who have severe disease and are disproportionately impacted by symptoms, exacerbations and overall illness burden. The care required for this relatively small proportion of patients is also significant and has a major impact on the healthcare system. A number of new therapies that hold promise for severe asthma are currently in clinical trials or are entering the Australian and international market. However, recognition of severe asthma in clinical practice is variable, and there is little consensus on the best models of care or how to integrate emerging and often costly therapies into current practice. In this article, we report on roundtable discussions held with severe asthma experts from around Australia, and make recommendations about approaches for better patient diagnosis and assessment. We assess current models of care for patient management and discuss how approaches may be optimized to improve patient outcomes. Finally, we propose mechanisms to assess new therapies and how to best integrate these approaches into future treatment.
Steinkamp's Toy Can Hop 100 Times But Can't Stand Up
Authors: Stiesberg Gregg , van Oijen Tim , Ruina Andy
Published: December 2016

We have experimented with and simulated Steinkamp's passive-dynamic hopper. This hopper cannot stand up (it is statically unstable), yet it can hop the length of a 5 m 0.079 rad sloped ramp, with n≈100 hops. Because, for an unstable periodic motion, a perturbation Δx0 grows exponentially with the number of steps (Δxn≈Δx0×λn), where λ is the system eigenvalue with largest magnitude, one expects that if λ>1 that the amplification after 100 steps, λ100, would be large enough to cause robot failure. So, the experiments seem to indicate that the largest eigenvalue magnitude of the linearized return map is less than one, and the hopper is dynamically stable. However, two independent simulations show more subtlety. Both simulations correctly predict the period of the basic motion, the kinematic details, and the existence of the experimentally observed period ∼11 solutions. However, both simulations also predict that the hopper is slightly unstable (|λ|max>1). This theoretically predicted instability superficially contradicts the experimental observation of 100 hops. Nor do the simulations suggest a stable attractor near the periodic motion. Instead, the conflict between the linearized stability analysis and the experiments seems to be resolved by the details of the launch: a simulation of the hand-holding during launch suggests that experienced launchers use the stability of the loosely held hopper to find a motion that is almost on the barely unstable limit cycle of the free device.
Dynamic Analysis for the Rotor Drop Process and Its Application to a Vertically Levitated Rotor/Active Magnetic Bearing System
Authors: Zhao Yulan , Yang Guojun , Keogh Patrick , Zhao Lei
Published: December 2016

Active magnetic bearings (AMBs) have been utilized widely to support high-speed rotors. However, in the case of AMB failure, emergencies, or overload conditions, the auxiliary bearing is chosen as the backup protector to provide mechanical supports and displacement constraints for the rotor. With lack of support, the auxiliary bearing will catch the dropping rotor. Accordingly, high contact forces and corresponding thermal generation due to mechanical rub are applied on the dynamic contact area. Rapid deterioration may be brought about by excessive dynamic and thermal shocks. Therefore, the auxiliary bearing must be sufficiently robust to guarantee the safety of the AMB system. Many approaches have been put forward in the literature to estimate the rotor dynamic motion, nonetheless most of them focus on the horizontal rotor drop and few consider the inclination around the horizontal plane for the vertical rotor. The main purpose of this paper is to predict the rotor dynamic behavior accurately for the vertical rotor drop case. A detailed model for the vertical rotor drop process with consideration of the rotating inclination around x- and y-axes is proposed in this paper. Additionally, rolling and sliding friction are distinguished in the simulation scenario. This model has been applied to estimate the rotor drop process in a helium circulator system equipped with AMBs for the 10 MW high-temperature gas-cooled reactor (HTR-10). The HTR-10 has been designed and researched by the Institute of Nuclear and New Energy Technology (INET) of Tsinghua University. The auxiliary bearing is utilized to support the rotor in the helium circulator. The validity of this model is verified by the results obtained in this paper as well. This paper also provides suggestions for the further improvement of auxiliary bearing design and engineering application.
Pressure-Based Ignition Delay Times of Non-Premixed Turbulent Jet Flames Using Various Turbulence Models
Authors: Samimi Abianeh O. , Levins M. , Chen C. P.
Published: December 2016

Pressure-based ignition delay times of turbulent spray combustion of n-dodecane fuel were studied using two turbulence models: Large Eddy Simulations (LES) of turbulence and Reynolds Averaged Navier Stokes (RANS). Standard RNG k-ε and Dynamic Structure models were utilized for RANS and LES turbulence modeling respectively. The simulated combustion chamber pressure rise, lift-off length, liquid penetration, and vapor penetration were compared with experimental data. The combustion chamber initial gas temperatures ranged from 850 K to 1200 K at an initial gas density of 22.8 kg/m3. A recently developed skeletal mechanism of n-dodecane with 85 species was utilized in the current work. The pressure-based ignition delay times using the Dynamic Structure turbulence model were well matched with experimental data, but the simulated pressure-based ignition delay time was over-predicted using RNG k-ε model at initial combustion chamber temperature of 850 K. The flame lift-off length, spray structure and species production and consumption histories were also investigated using different models. Both turbulence models show similar spray lift-off length at time of luminosity-based ignition delay at various combustion chamber temperatures.
Biofuel Emulsifier Using High Velocity Impinging Flows and Singularities in Micro-Channels
Authors: Belkadi A. , Montillet A. , Bellettre J.
Published: December 2016

The objective of this work is to design an original microfluidic mixer for continuous emulsification of small fractions of water in a lipid phase. This system is aimed to be integrated on-line in the process so as to avoid the use of a surfactant. The targeted application is a better combustion of alternative biofuels in boilers, turbines or internal combustion engines in general. The developed micro-system which includes impinging flows and elbows, is performed on the basis of a specific design of micro-channels, adapted to the respective flow rates and the characteristics of the fluids to be emulsified (viscosity, surface tension). The variation of different parameters is tested in this study such as the nature of the lipid phase (viscosity, density, surface tension and components), the length of micro-channels in the elbow and the flow rate of the dispersed phase. The dispersion of water is much more efficient with this microsystem using gasoil rather than vegetable oil as the continuous phase.
Effects of Amorphous Ti-Al-B Nanopowder Additives on Combustion in a Single-Cylinder Diesel Engine
Authors: Fisher Brian T. , Cowart Jim S. , Weismiller Michael R. , Huba Zachary J. , Epshteyn Albert
Published: December 2016

Energetic nanoparticles have shown promise as additives to liquid hydrocarbon fuels due to their high specific surface area, high energy content, and catalytic capability. Novel amorphous reactive mixed-metal nanopowders (RMNPs) containing Ti, A1, and B, synthesized via a sonochemical reaction, have been developed at the Naval Research Laboratory. These materials have higher energy content than commercial nano-aluminum (nano-A1), making them potentially useful as energy-boosting fuel components rather than simply catalytic additives. This work examines the combustion behavior of these RMNPs in a small, single-cylinder, 4-stroke diesel engine (Yanmar L48V). Fuel formulations included varying fractions of RMNPs, up to 4 wt. %, suspended in jet fuel JP-5. Comparative experiments also were conducted with equivalent suspensions of nano-A1 in JP-5. For each fuel formulation, with the engine operating at constant speed of 3000 RPM, load was varied across its full range. At each load, cylinder pressure data were recorded for 30 seconds (750 cycles) to enable determination of important combustion characteristics. Although differences were small, both nano-A1 and RMNPs resulted in shorter ignition delays, retarded peak pressure locations, decreased maximum rates of heat release, and increased burn durations. In addition, a similar but larger engine (Yanmar L100V) was used to examine fuel consumption and emissions for a suspension of 8 wt. % RMNPs in JP-5 (and 8 wt. % nano-A1 for comparison). The engine was connected to a genset operating at a constant speed of 3600 RPM and constant load with nominal gIMEP (gross indicated mean effective pressure) of 6.5 bar. Fuel consumption rate was determined from time required to consume 175 mL of each fuel formulation, while emissions levels were recorded once per minute during that time. Unfortunately, combustion data and visual inspection of the injector indicated that RMNPs led to significant deposits on the injector tip and in and around the orifices, which had a negative impact on both fuel consumption rate and emissions. The engine stalled after four minutes of operation with the nano-A1-laden fuel, apparently due to clogging at the bottom of the fuel reservoir. It was concluded that particle settling in the fuel reservoir and particle clogging in the fuel system and injector were significant problems for these composite liquid/powder fuels. Nevertheless, fuel consumption rate was found to be 17% lower for the nano-A1 suspension compared to baseline JP-5 for the period of time that the engine was able to operate, which is a significant achievement towards demonstrating the potential value of reactive metal powder additives in boosting the volumetric energy density of hydrocarbon fuels.
Numerical Investigation on Mixture Formation of Two-Stroke LPG Direct Injection Engine Used as Range Extender for Electric Car
Authors: Xu B. Y. , Qi Y. L. , Sun C. D. , Ma J. Z.
Published: December 2016

The two-stroke DI engine has distinct advantages such as high speed, high power density, and simple structure . LPG has a low boiling point and high saturation vapor pressure, which is very helpful in accelerating the fuel-air mixing. Owing to these characteristics and advantages, the two-stroke LPG engine is generally regarded as the preferred power source of the generator unit for extended-range electrical vehicles. The process of mixture formation is numerically simulated after the calculation model is validated by results from optical experiments. The results show that, under conditions of avoidance of fuel short-circuiting, an injection timing of 50° CA ABDC for engine start and warming (2000 rpm), and an 40° CA ABDC for running as the power source of the generator (4800 rpm) are appropriate. Further analysis of the velocity and concentration fields shows that the fresh mixture is locked in the cylinder when the exhaust port is closed (73° CA ABDC) and the homogeneous mixture can be formed at spark timing.
Study on Feature Extraction Method for Diesel Engine Valve Faults
Authors: Fei Hongzi , Liu Long , Li Xuemin , Ma Xiuzhen
Published: December 2016

Valve faults diagnosis technique of a diesel engine is studied deeply in this paper. The experiment of valve clearance and air leakage faults are done in a diesel engine, and cylinder head vibration and transient speed signals are measured synchronously on normal and fault conditions respectively. These signals are used to feature extraction. In order to avoid the leakage and aliasing of vibration signal’s frequent spectrum, resample method based on order tracking is proposed, and vibration signal was transformed from time domain to crank angle domain accurately. Considering the non-stationary characteristic of vibration signal, a series of intrinsic mode functions with different scales were obtained using the empirical mode decomposition method, and fault features parameters were extracted through 3D Hilbert spectrums of the intrinsic mode functions. Experimental results show that the method can effectively extract fault features of diesel engine and use them to realize the valve system faults diagnosis further.
Evaluation of Emissions Characteristics by Charging Exhaust Gas From Lean Burn Gas Engine Into Marine Diesel Engine
Authors: Nitta Yoshifuru , Yoo Dong-Hoon , Nishio Sumito , Ichikawa Yasuhisa , Hirata Koichi , Yamasaki Yudai
Published: December 2016

Reductions of Nitrogen oxides (NOx), sulphur oxides (SOx) and carbon dioxide (CO2) emissions have been acknowledged on the global level. The International Maritime Organization (IMO) has developed some mandatory or non-mandatory instruments such as codes, amendments, recommendations or guidelines to strengthen the emissions regulations on ships engaged in international voyage. However, it is difficult to meet the strengthened emissions regulations on the conventional marine diesel engines. Lean burn gas engines have been thus recently attracting attention in the maritime industry. The lean burn gas engines use natural gas as fuel and can simultaneously reduce both NOx and CO2 emissions. On the other hand, since methane is the main component of natural gas, the slipped methane which is the unburned methane emitted from the lean burn gas engines might have a potential impact on global warming. The authors investigated on a ship installed conventional marine diesel engines and lean burn gas engines, and have proposed a C-EGR (combined exhaust gas recirculation) system to reduce the slipped methane from the gas engines and NOx from marine diesel engines. This system consists of a marine diesel engine and a lean burn gas engine, and the exhaust gas emitted from the lean burn gas engine is provided to the intake manifold of the marine diesel engine by a blower installed between both engines. Since exhaust gas from the gas engine including slipped methane, this system could reduce both the NOx from the marine diesel engine and the slipped methane from the lean burn gas engine simultaneously. This paper introduces the details of the proposed C-EGR system, and presents the experimental results of emissions and engine performance characteristics on the C-EGR system. In the experiment, the diesel engine was operated at three load conditions of 25, 50 and 75% along with the propeller load curve. In order to keep the slipped methane concentration constant, the gas engine was operated at a constant load condition of 25%. The intake exhaust gas quantity which is supplied to the diesel engine was adjusted by the blower speed. As a result, it was confirmed that the C-EGR system attained more than 75% reduction of the slipped methane in the intake gas. In addition, the NOx emission from the diesel engine decreased with the effect of the EGR system. Also the fuel consumption of the diesel engine did not increase, because of the methane combustion in the intake gas.
The Impact of Low Octane Primary Reference Fuel on HCCI Combustion Burn Rates: The Role of Thermal Stratification
Authors: Hagen Luke , Lavoie George , Wooldridge Margaret , Assanis Dennis
Published: December 2016

A new experimental method was developed which isolated charge composition effects for wide levels of internal EGR (iEGR) at constant total EGR (tEGR) for negative valve overlap (NVO) homogeneous charge compression ignition (HCCI) combustion. Using this method, the effect of changing iEGR was examined for both research grade gasoline (RON = 90.5) and PRF40 across multiple engine speeds and at constant charge composition. For this study, the charge composition was defined as the total mass of fresh air, fuel and tEGR. Comparison also was made between the two fuels at a fixed iEGR level to isolate, independent of compositional effects, the effect of a low octane fuel on HCCI burn rates.

From the experimental results, for all engine speeds, for a given iEGR level, PRF40 was found to have a reduced burn duration and higher maximum heat release rate (HRR) compared with gasoline. PRF40 was found to have a nearly constant burn duration and HRR for a given load and CA50, largely independent of engine speed and iEGR level. Gasoline, for equivalent conditions, showed an increased burn duration at higher iEGR levels.

When comparing PRF40 to gasoline at fixed speed, combustion phasing and iEGR level, the increase in HRR was found to coincide with reduced intake valve closing (IVC) temperatures necessary to maintain constant combustion phasing for the PRF40. The reduced IVC temperature for PRF40 reduced the thermal stratification in-cylinder compared with gasoline and may have been the cause of this change. To examine the impact of thermal gradients relative to fuel chemistry, a multi-zone “balloon model” was used to evaluate experimental conditions. The model used a reduced chemical kinetic mechanism for PRFs with PRF87 representing gasoline. The results of the model demonstrated that when the in-cylinder temperature profiles between PRF40 and PRF87 were matched by adjusting wall temperature, the heat release rates were nearly identical. This result suggested the observed differences in burn rates between gasoline and PRF40 were influenced to a large degree by differences in thermal stratification, and to a lesser extent by differences in fuel chemistry.
Effects of Fuel Quantity on Soot Formation Process for Biomass-Based Renewable Diesel Fuel Combustion
Authors: Jing Wei , Wu Zengyang , Roberts William L. , Fang Tiegang
Published: December 2016

Soot formation process was investigated for biomass-based renewable diesel fuel, such as biomass to liquid (BTL), and conventional diesel combustion under varied fuel quantities injected into a constant volume combustion chamber. Soot measurement was implemented by two-color pyrometry under quiescent type diesel engine conditions (1000 K and 21% O2 concentration). Different fuel quantities, which correspond to different injection widths from 0.5 ms to 2 ms under constant injection pressure (1000 bar), were used to simulate different loads in engines. For a given fuel, soot temperature and KL factor show a different trend at initial stage for different fuel quantities, where a higher soot temperature can be found in a small fuel quantity case but a higher KL factor is observed in a large fuel quantity case generally. Another difference occurs at the end of combustion due to the termination of fuel injection. Additionally, BTL flame has a lower soot temperature, especially under a larger fuel quantity (2 ms injection width). Meanwhile, average soot level is lower for BTL flame, especially under a lower fuel quantity (0.5 ms injection width). BTL shows an overall low sooting behavior with low soot temperature compared to diesel, however, trade-off between soot level and soot temperature needs to be carefully selected when different loads are used.
Model Predictive Engine Speed Control for Transmissions With Dog Clutches
Authors: Zhu Qilun , Prucka Robert , Prucka Michael , Dourra Hussein
Published: December 2016

The need for cost-effective fuel economy improvements has driven the introduction of automatic transmissions with an increasing number of gear ratios. Incorporation of interlocking dog clutches in these transmissions decreases package space and increases efficiency, as compared to conventional dry or wet clutches. Unlike friction based clutches, interlocking dog clutches require very precise rotational speed matching prior to engagement. Precise engine speed control is therefore critical to maintaining high shift quality. This research focuses on controlling the engine speed during a gearshift period by manipulating throttle position and combustion phasing. Model predictive control (MPC) is advantageous in this application since the speed profile of a future prediction horizon is known with relatively high confidence. The MPC can find the optimal control actions to achieve the designated speed target without invoking unnecessary actuator manipulation and violating hardware and combustion constraints. This research utilizes linear parameter varying (LPV) MPC to control the engine speed during the gearshift period. Combustion stability constraints are considered with a control oriented covariance of indicated mean effective pressure model (COV of IMEP). The proposed MPC engine speed controller is validated with a high-fidelity 0-dimensional engine model with crank angle resolution. Four case studies, based on simulation, investigate the impact of different MPC design parameters. They also demonstrate that the proposed MPC engine controller successfully achieves the speed reference tracking objective while considering combustion variation constraints.
Inverse Analysis of In-Cylinder Gas-Wall Boundary Conditions: Investigation of a Yittria Stabilized Zirconia Thermal Barrier Coating for Homogeneous Charge Compression Ignition
Authors: O’Donnell Ryan , Powell Tommy , Hoffman Mark , Filipi Zoran
Published: December 2016

Thermal Barrier Coatings (TBC) applied to in-cylinder surfaces of a Low Temperature Combustion (LTC) engine provide opportunities for enhanced cycle efficiency via two mechanisms: (i) positive impact on thermodynamic cycle efficiency due to combustion/expansion heat loss reduction, and (ii) enhanced combustion efficiency. Heat released during combustion elevates TBC surface temperatures, directly impacting gas-wall heat transfer. Determining the magnitude and phasing of the associated TBC surface temperature swing is critical for correlating coating properties with the measured impact on combustion and efficiency. Although fast-response thermocouples provide a direct measurement of combustion chamber surface temperature in a metal engine, the temperature and heat flux profiles at the TBC-treated gas-wall boundary are difficult to measure directly. Thus, a technique is needed to process the signal measured at the sub-TBC sensor location and infer the corresponding TBC surface temperature profile. This task can be described as an Inverse Heat Conduction Problem (IHCP), and it cannot be solved using the conventional analytic/numeric techniques developed for ‘direct’ heat flux measurements.

This paper proposes using an Inverse Heat Conduction solver based on the Sequential Function Specification Method (SFSM) to estimate heat flux and temperature profiles at the wall-gas boundary from measured sub-TBC temperature. The inverse solver is validated ex situ under HCCI like thermal conditions in a custom fabricated radiation chamber where fast-response thermocouples are exposed to a known heat pulse in a controlled environment. The analysis is extended in situ, to evaluate surface conditions in a single-cylinder, gasoline-fueled, HCCI engine. The resulting SFSM-based inverse analysis provides crank angle resolved TBC surface temperature profiles over a host of operational conditions.

Such metrics may be correlated with TBC thermophysical properties to determine the impact(s) of material selection on engine performance, emissions, heat transfer, and efficiencies. These efforts will also guide next-generation TBC design.
Genotoxicity of Diesel Particulate Matter Emitted by Port-Injection of Hydrous Ethanol and N-Butanol
Authors: Cadrazco Marlon , Agudelo John R. , Orozco Luz Y. , Estrada Verónica
Published: December 2016

This work evaluated the genotoxic potential of the soluble organic material (SOM) extracted from the particulate matter (PM) emitted by an automotive diesel engine. The engine was modified to operate with a home-made multipoint-port injection system to substitute 10% of ultra-low-sulfur diesel (ULSD) fuel in energy basis by hydrous ethanol (h-Et) or n-butanol (n-Bu) injected into the manifold during the intake stroke. A low engine load mode named M4 (43 Nm at 2410 min−1) and a medium-load mode M2 (95 Nm at 2410 min−1) were selected from the vehicle homologation cycle. PM was collected with a stainless steel filter located 1.5 m downstream the exhaust manifold. The SOM of the PM was extracted to evaluate the genotoxic activity on human lymphocytes using the Comet assay. Results indicated that independently of the mode, the SOM coming from alcohols led more genotoxicity than ULSD, following the order h-Et > n-Bu > ULSD. The low engine load operation exhibited much more DNA damage than mode M2, especially the PM produced by hydrous ethanol port-injection. Although further research is still necessary, these findings suggest that the biology activity of the SOM coming from alcohols PM could be a barrier for the implementation of alcohol port-injection technology.
Characterization of Variations in Cylinder Peak Pressure and its Position of High-Power Turbo-Charged Compression-Ignition Engines
Authors: Chen Gong
Published: December 2016

Cylinder peak pressure (pmax) over operating cycle of a high-power turbo-charged compression-ignition engine indicates its in-cylinder combustion behavior and also the level of mechanical load acting on its power assembly components. It is significantly important to understand how pmax with cylinder pressure (p) varies due to possible changes in engine design and operation input condition parameters. The input parameters considered in this paper include piston crank-angle position (θ), compression ratio (CR), amount of cycle burning heat (Q), injection/combustion duration (Δθ), and fuel injection/combustion-start timing (θs). Effects of the input parameters to pmax and θpmax which is the crank-angle position of pmax in engines of this type are analyzed, predicted and characterized. Results with the approaches to achieving those are presented. It is indicated from the results that the crank-angle position of combustion duration (Δθ) has a significant effect on θpmax for a given engine power density. As the position of Δθ varies, θpmax varies accordingly and can be determined. It is also indicated that as θs is sufficiently retarded from a position before the top dead center (TDC) to a point close to TDC, either before or after, in a large-bore high-power turbocharged engine, the trend of pmax variation would be reversed. This establishes the minimum value of pmax over the range of engine combustion-start timing variation. The results and indications are beneficial and usefully needed in adjusting the design and operation input condition parameters for achieving optimized balances between power-output capacity, fuel efficiency, exhaust emissions and mechanical/thermal loading of engines in this type.