bluuebunny/crossref_metadata_2025 huggingface dataset:
Edge Computing-Based Internet of Things Framework for Indoor Occupancy Estimation
Authors: Rastogi Krati , Lohani Divya
Published: September 2020

Indoor occupancy estimation has become an important area of research in the recent past. Information about the number of people entering or leaving a building is useful in estimation of hourly sales, dynamic seat allocation, building climate control, etc. This work proposes a decentralized edge computing-based IoT framework in which the majority of the data analytics is performed on the edge, thus saving a lot of time and network bandwidth. For occupancy estimation, relative humidity and carbon dioxide concentration are used as inputs, and estimation models are developed using multiple linear regression, quantile regression, support vector regression, kernel ridge regression, and artificial neural networks. These estimations are compared using execution speed, power consumption, accuracy, root mean square error, and mean absolute percentage error.
Determinants of Cloud Business Intelligence Adoption Among Ghanaian SMEs
Authors: Owusu Acheampong
Published: September 2020

This study explores the determinants of Cloud BI adoption among Ghanaian small-medium enterprises (SMEs). The study was guided by the technology-organization-environment (TOE) framework and information systems adoption model and employed the qualitative method through an in-depth interview with data collected from CEOs/key managers from 17 SMEs in Ghana. The results showed that technological characteristics (relative advantage, complexity, and compatibility), organizational characteristics (organization size and organizational readiness), environmental characteristics (competitive pressure and regulatory framework), and owner-manager characteristics (innovativeness and knowledge) influence the adoption of Cloud BI tools and services in Ghanaian SMEs. This study contributes to the body of knowledge by providing a Cloud BI adoption model from a developing country context. Practically, the study provides insights to vendors about the kind of Cloud BI Ghanaian SMEs require. Vendors can also use the findings to create awareness about the services they offer in terms of Cloud BI.
Computer-Assisted Analysis of Human Semen Concentration and Motility
Authors: Boumaza Karima , Loukil Abdelhamid
Published: September 2020

Computer-assisted semen analysis systems insist on evaluating sperm characteristics. These systems afford capacity to study and evaluate sperm statistical and morphological characteristics such as concentration, morphology, and motility, which have an important role in diagnosis and treatment of male infertility. In this paper, the proposed algorithm allows the assessment of concentration and motility rate of sperms in microscopic videos. First, enhancement process is required because of microscopic images limitations such as low contrast and noises. Then, for true sperm recognition among noise and debris, a hybrid approach is proposed using a combination between segmentation techniques. After, the use of geometric features of the bounding ellipse of the sperm head led to define sperm concentration. Finally, inter-frame difference is applied for motile sperm detection. The proposed method was tested on microscopic videos of human semen; the performance of this method is analyzed in terms of speed, accuracy, and complexity. Obtained results during the experiments are very promising compared with those obtained by the traditional assessment, which is the most widely used and approved in the laboratories.
Recommendation-Based Meta-Search Engine for Suggesting Relevant Documents Links
Authors: Ayaz A. Salman , Venkat Jaya A , Gulzar Zameer
Published: September 2020

The information available online is mostly present in an unstructured form and search engines are indispensable tools especially in higher education organizations for obtaining information from the Internet. Various search engines were developed to help learners to retrieve the information but unfortunately, most of the information retrieved is not relevant. The main objective of this research is to provide relevant document links to the learners using a three-layered meta-search architecture. The first layer retrieves information links from the web based on the learner query, which is then fed to the second layer where filtering and clustering of document links are done based on semantics. The third layer, with the help of a reasoner, categorizes information into relevant and irrelevant information links in the repository. The experimental study was conducted on a training data set using web queries related to the domain of sports, entertainment, and academics. The results indicate that the proposed meta-search engine performs well as compared to another stand-alone search engine with better recall.
An E-Portfolio as an Assessment Strategy in an Open Distance Learning Context
Authors: Makokotlela Matlala V.
Published: September 2020

There has been a growing interest in using an e-portfolio as an alternative method of assessment in an open distance eLearning environment. The use of an e-portfolio as another method of assessment in Environmental Education (EE) has not been sufficiently researched. The purpose of this study was to explore how the use of an e-Portfolio as an alternative method of assessment enhances pre-service teachers' technological pedagogy in an environmental education module. Qualitative data was collected using interviews and document analysis. The study employed interpretive paradigm, connectivism theory, and purposive sampling. A qualitative approach was employed to analyse and identify emerging themes from the data. The qualitative findings are that the e-portfolio was significant in assessing sustainable education, enhanced the pre-service teachers' digital pedagogy. Challenges included a lack of computer skills, connectivity, support during compilation of e-portfolio, and sufficient activities to promote teachers' digital pedagogy.
Study on Low Cycle Fatigue and Tensile Behavior of Al 5083/CNT/MoB/Ni Hybrid Composite
Authors: Rahiman A.H. Sajeeb , Robinson Smart D.S.
Published: September 2020

The paper is on low cycle fatigue and tensile behavior of hybrid composite with Al5083 alloy as matrix material and different weight percentages of multi-walled carbon nanotube (CNT), molybdenum boride (MoB), and nickel (Ni) as reinforcements. Low cycle fatigue test is conducted loading with a stress ratio of 0.1 and maximum load of 50 kN. Both tensile properties and fatigue life for the composites are found to be increasing initially with increase in percentage weight of reinforcements up to a CNT weight percentage of 0.75. When the percentage of reinforcement further increases the properties show a decreasing trend. The scanning electron microscopy (SEM) of the ruptured fatigue specimen indicates that the increase in properties is due to grain size refinement and the decreasing trend is because of CNT cluster formation.
Professor Sena S. De Silva (1946 – 2020)
Authors: Amarasinghe Upali S. , T. Cumaranatunge P. Ruchira , S. Wijeyaratne M. Jayantha
Published: September 2020

No Abstract avaialble
A Genetic Model of Constitutively Active Integrin CD11b/CD18
Authors: Martinez Laisel , Li Xiaobo , Ramos-Echazabal Gioser , Faridi Hafeez , Zigmond Zachary M. , Santos Falcon Nieves , Hernandez Diana R. , Shehadeh Serene A. , Velazquez Omaida C. , Gupta Vineet , Vazquez-Padron Roberto I.
Published: September 2020

Pharmacological activation of integrin CD11b/CD18 (αMβ2, Mac-1, and CR3) shows anti-inflammatory benefits in a variety of animal models of human disease, and it is a novel therapeutic strategy. Reasoning that genetic models can provide an orthogonal and direct system for the mechanistic study of CD11b agonism, we present in this study, to our knowledge, a novel knock-in model of constitutive active CD11b in mice. We genetically targeted the Itgam gene (which codes for CD11b) to introduce a point mutation that results in the I332G substitution in the protein. The I332G mutation in CD11b promotes an active, higher-affinity conformation of the ligand-binding I/A-domain (CD11b αA-domain). In vitro, this mutation increased adhesion of knock-in neutrophils to fibrinogen and decreased neutrophil chemotaxis to a formyl–Met–Leu–Phe gradient. In vivo, CD11bI332G animals showed a reduction in recruitment of neutrophils and macrophages in a model of sterile peritonitis. This genetic activation of CD11b also protected against development of atherosclerosis in the setting of hyperlipidemia via reduction of macrophage recruitment into atherosclerotic lesions. Thus, our animal model of constitutive genetic activation of CD11b can be a useful tool for the study of integrin activation and its potential contribution to modulating leukocyte recruitment and alleviating different inflammatory diseases.
Staphylococcal Enterotoxin C2 Mutant–Directed Fatty Acid and Mitochondrial Energy Metabolic Programs Regulate CD8+ T Cell Activation
Authors: Fu Xuanhe , Xu Mingkai , Zhang Huiwen , Li Yongqiang , Li Yansheng , Zhang Chenggang
Published: September 2020

CD8+ T cells can switch between fatty acid catabolism and mitochondrial energy metabolism to sustain expansion and their cytotoxic functions. ST-4 is a TCR-enhanced mutant derived from superantigen staphylococcal enterotoxin C2 (SEC2), which can hyperactivate CD4+ T cells without MHC class II molecules. However, whether ST-4/SEC2 can enhance metabolic reprogramming in CD8+ T cells remains poorly understood. In this study, we found that ST-4, but not SEC2, could induce proliferation of purified CD8+ T cell from BALB/c mice in Vβ8.2- and -8.3–specific manners. Results of gas chromatography–mass spectroscopy analysis showed that fatty acid contents in CD8+ T cells were increased after ST-4 stimulation. Flow cytometry and Seahorse analyses showed that ST-4 significantly promoted mitochondrial energy metabolism in CD8+ T cells. We also observed significantly upregulated levels of gene transcripts for fatty acid uptake and synthesis, and significantly increased protein expression levels of fatty acid and mitochondrial metabolic markers of mTOR/PPARγ/SREBP1 and p38-MAPK signaling pathways in ST-4–activated CD8+ T cells. However, blocking mTOR, PPARγ, SREBP1, or p38-MAPK signals with specific inhibitors could significantly relieve the enhanced fatty acid catabolism and mitochondrial capacity induced by ST-4. In addition, blocking these signals inhibited ST-4–stimulated CD8+ T cell proliferation and effector functions. Taken together, our findings demonstrate that ST-4 enhanced fatty acid and mitochondria metabolic reprogramming through mTOR/PPARγ/SREBP and p38-MAPK signaling pathways, which may be important regulatory mechanisms of CD8+ T cell activation. Understanding the effects of ST-4–induced regulatory metabolic networks on CD8+ T cells provide important mechanistic insights to superantigen-based tumor therapy.
A Complement C3–Specific Nanobody for Modulation of the Alternative Cascade Identifies the C-Terminal Domain of C3b as Functional in C5 Convertase Activity
Authors: Pedersen Henrik , Jensen Rasmus K. , Jensen Jens Magnus B. , Fox Rachel , Pedersen Dennis V. , Olesen Heidi G. , Hansen Annette G. , Christiansen Dorte , Mazarakis Sofia M. M. , Lojek Neal , Hansen Pernille , Gadeberg Trine A. F. , Zarantonello Alessandra , Laursen Nick S. , Mollnes Tom Eirik , Johnson Matthew B. , Stevens Beth , Thiel Steffen , Andersen Gregers R.
Published: September 2020

The complement system is an intricate cascade of the innate immune system and plays a key role in microbial defense, inflammation, organ development, and tissue regeneration. There is increasing interest in developing complement regulatory and inhibitory agents to treat complement dysfunction. In this study, we describe the nanobody hC3Nb3, which is specific for the C-terminal C345c domain of human and mouse complement component C3/C3b/C3c and potently inhibits C3 cleavage by the alternative pathway. A high-resolution structure of the hC3Nb3–C345c complex explains how the nanobody blocks proconvertase assembly. Surprisingly, although the nanobody does not affect classical pathway–mediated C3 cleavage, hC3Nb3 inhibits classical pathway–driven hemolysis, suggesting that the C-terminal domain of C3b has an important function in classical pathway C5 convertase activity. The hC3Nb3 nanobody binds C3 with low nanomolar affinity in an SDS-resistant complex, and the nanobody is demonstrated to be a powerful reagent for C3 detection in immunohistochemistry and flow cytometry. Overall, the hC3Nb3 nanobody represents a potent inhibitor of both the alternative pathway and the terminal pathway, with possible applications in complement research, diagnostics, and therapeutics.
β-catenin mediates the effect of GLP-1 receptor agonist on ameliorating hepatic steatosis induced by high fructose diet
Authors: Gao Zhe , Song Guang-Yao , Ren Lu-Ping , Ma Hui-Juan , Ma Bo-Qing , Chen Shu-Chun
Published: September 2020

The hypoglycemic drug GLP-1 receptor agonist can ameliorate hepatic steatosis but the mechanism is not clear. Intake of high fructose leads to non-alcoholic fatty liver disease by stimulating lipid synthesis, and β-catenin is the key molecule for realizing GLP-1 function in extrahepatic tissues; with the discovery of GLP-1 receptor in liver, we speculate that β-catenin might mediate GLP-1 receptor agonist on ameliorating hepatic steatosis induced by high fructose. Wistar rats were fed with high fructose diet for 8 weeks and then treated with GLP-1 receptor agonist exenatide for 4 weeks; the changes of lipid synthesis pathway factors, the expression and nuclear translocation of β-catenin, and the hepatic steatosis of the rats were observed. After the intervention of exenatide, the hepatic steatosis induced by high fructose was improved, the nuclear translocation and expression of β-catenin were facilitated, and the mRNA and protein expression of the upstream regulator SREBP-1 and the downstream key enzymes ACC, FAS and SCD-1 of de novo lipogenesis were down-regulated. GLP-1 receptor agonist may ameliorate hepatic steatosis induced by high fructose by β-catenin regulating de novo lipogenesis pathway. GLP-1 receptor agonist may be a potential new drug for the treatment of non-alcoholic fatty liver disease, and the β-catenin may be an important target for the drug therapy.
High-flow nasal cannula for Acute Respiratory Distress Syndrome (ARDS) due to COVID-19
Authors: Panadero Carolina , Abad-Fernández Araceli , Rio-Ramírez Mª Teresa , Acosta Gutiérrez Carmen Maria , Calderón-Alcalá Mariara , López-Riolobos Cristina , Matesanz-López Cristina , Garcia-Prieto Fernando , Diaz-Garcia Jose Maria , Raboso-Moreno Beatriz , Vasquez-Gambasica Zully , Andres-Ruzafa Pilar , García-Satué Jose Luis , Calero-Pardo Sara , Sagastizabal Belen , Bautista Diego , Campos Alfonso , Gonzalez Marina , Grande Luis , Jimenez Fernandez Marta , Santiago-Ruiz Jose L. , Caravaca Perez Pedro , Alcaraz Andres Jose
Published: September 2020

Background: High-flow nasal cannula oxygen therapy (HFNC) has been shown to be a useful therapy in the treatment of patients with Acute Respiratory Distress Syndrome (ARDS), but its efficacy is still unknown in patients with COVID-19. Our objective is to describe its utility as therapy for the treatment of ARDS caused by SARS-CoV-2. Methods: A retrospective, observational study was performed at a single centre, evaluating patients with ARDS secondary to COVID-19 treated with HFNC. The main outcome was the intubation rate at day 30, which defined failure of therapy. We also analysed the role of the ROX index to predict the need for intubation.Results: In the study period, 196 patients with bilateral pneumonia were admitted to our pulmonology unit, 40 of whom were treated with HFNC due to the presence of ARDS. The intubation rate at day 30 was 52.5%, and overall mortality was 22.5%. After initiating HFNC, the SpO2/FiO2 ratio was significantly better in the group that did not require intubation (113.4±6.6 vs 93.7±6.7, p=0.020), as was the ROX index (5.0±1.6 vs 4.0±1.0, p=0.018). A ROX index less than 4.94 measured 2 to 6 h after the start of therapy was associated with increased risk of intubation (HR 4.03 [95% CI 1.18 – 13.7]; p=0.026).Conclusion: High-flow therapy is a useful treatment in ARDS in order to avoid intubation or as a bridge therapy, and no increased mortality was observed secondary to the delay in intubation. After initiating HFNC, a ROX index below 4.94 predicts the need for intubation.
Supervisor Perceptions of Newly Credentialed Athletic Trainers' Transition to Practice
Authors: Compton Samantha , Simon Janet E. , Harris Laura L.
Published: September 2020

Context

Transition to practice for newly credentialed athletic trainers (ATs) has been described through the perspective of educators, supervisors of graduate assistant ATs, students, and recent graduates; however, the opinion of supervisors of full-time ATs has not been thoroughly investigated.

Objective

(1) Describe supervisor perceptions of the transition to full-time practice for newly credentialed ATs and (2) describe current onboarding processes used by employers.

Design

Phenomenological qualitative study.

Setting

Semistructured interviews.

Patients or Other Participants

Purposive sample of 10 (4 men, 6 women) supervisors of newly credentialed ATs. Supervisors reported an average of 13.5 years of supervisory experience (range, 5–26 years).

Data Collection and Analysis

Questions addressed supervisor expectations, strengths and weaknesses of newly credentialed ATs, and the organization's onboarding process. The primary researcher transcribed audio recordings and each participant reviewed transcripts. Two researchers coded themes using an inductive process; a peer auditor completed an independent review. Disagreements were negotiated until consensus was reached.

Results

Two categories emerged: (1) characteristics of newly credentialed ATs and (2) onboarding strategies. The first category was organized into 2 subcategories: (1) knowledge, skills, and abilities (KSAs) and (2) unrealistic job expectations. The majority of supervisors felt that newly credentialed ATs were knowledgeable; however, the translation of knowledge into practice was viewed as an area requiring mentorship. Participants also reported that newly credentialed ATs often were poorly informed of the work schedule and time demands. In regard to onboarding processes, the researchers identified 7 different strategies reported by supervisors.

Conclusions

Newly credentialed ATs were perceived as knowledgeable but struggling to transition knowledge to clinical practice and often did not understand the work demands. Seven onboarding strategies were reported by participants; each of these can be used to develop KSAs of newly credentialed ATs. The KSAs should be addressed through a yearlong process consisting of orientations, shadowing, mentorship, seminars, and skill assessments.
How to choose appropriate medication for overactive bladder
Authors: Kuo Hann-Chorng
Published: September 2020

Medical treatment of overactive bladder (OAB) includes antimuscarinic agents, beta-3 adrenoceptor agonist (mirabegron), or combination with both drugs. Recently, a meta-analysis reported the integrated clinical trial data from 10 phase 2–4, double-blind, 12-week mirabegron monotherapy studies. The results confirmed that mirabegron is as effective as the previously used antimuscarinic agent to treat OAB. The treatment-emergent adverse events were similar across subgroups. This article comments on this largest integrated clinical trial data analysis, and reviews the recently published literature and tries to reveal how to choose the appropriate medication for OAB. For OAB patients, starting from antimuscarinic agent is feasible. However, if the patients have risk of cognitive dysfunction, a history of constipation, dry mouth, and urinary retention, starting with mirabegron 50 mg might be more safe and appropriate. In the elderly patients with low detrusor contractility, with central nervous system lesion, and men with benign prostatic hyperplasia, starting from 25 mg mirabegron is recommended. If the treatment result is not satisfactory to the 25 mg mirabegron, increase dose to 50 mg mirabegron is appropriate. In patients who have failed from the first OAB medication either with antimuscarinics or mirabegron 50 mg, the exchange of the OAB medication to each other should be tried first. If the treatment result is still not satisfactory, a combination of antimuscarinics and mirabegron is recommended.
Arterial stiffness
Authors: Tsai Jen-Pi , Hsu Bang-Gee
Published: September 2020

Apart from the result of multiple diseases as well as aging, arterial stiffness (AS) predicts cardiovascular disease (CVD), especially in patients with chronic kidney disease (CKD). Patients with CKD have high CVD prevalence, and an extraordinarily high risk for CVD might be related to nontraditional risk factors, including AS. The mechanism of AS development could be attributed to oxidative stress, inflammation, uremic milieu (e.g., uremic toxins), vascular calcification, and cumulative effects of traditional cardiovascular risk factors on arteries such as diabetes mellitus or hypertension. There were a variety of non-invasive techniques to measure AS. One of these techniques is carotid–femoral pulse wave velocity, which is the reference measurement of AS and is related to long-term CVD outcomes. AS progression has corresponding medical treatments with modest beneficial results. This review briefly discusses the risk factors, measurements, and treatments associated with AS.
TM4SF4 and LRRK2 Are Potential Therapeutic Targets in Lung and Breast Cancers through Outlier Analysis
Authors: Jung Kyungsoo , Choi Joon-Seok , Koo Beom-Mo , Kim Yu Jin , Song Ji-Young , Sung Minjung , Chang Eun Sol , Noh Ka-Won , An Sungbin , Lee Mi-Sook , Song Kyoung , Lee Hannah , Kim Ryong Nam , Shin Young Kee , Oh Doo-Yi , Choi Yoon-La
Published: September 2020

PurposeTo find biomarkers for disease, there have been constant attempts to investigate the genes that differ from those in the disease groups. However, the values that lie outside the overall pattern of a distribution, the outliers, are frequently excluded in traditional analytical methods as they are considered to be ‘some sort of problem.’ Such outliers may have a biologic role in the disease group. Thus, this study explored new biomarker using outlier analysis, and verified the suitability of therapeutic potential of two genes (TM4SF4 and LRRK2).Materials and MethodsModified Tukey’s fences outlier analysis was carried out to identify new biomarkers using the public gene expression datasets. And we verified the presence of the selected biomarkers in other clinical samples via customized gene expression panels and tissue microarrays. Moreover, a siRNA-based knockdown test was performed to evaluate the impact of the biomarkers on oncogenic phenotypes.ResultsTM4SF4 in lung cancer and LRRK2 in breast cancer were chosen as candidates among the genes derived from the analysis. TM4SF4 and LRRK2 were overexpressed in the small number of samples with lung cancer (4.20%) and breast cancer (2.42%), respectively. Knockdown of TM4SF4 and LRRK2 suppressed the growth of lung and breast cancer cell lines. The LRRK2 overexpressing cell lines were more sensitive to LRRK2-IN-1 than the LRRK2 under-expressing cell linesConclusionOur modified outlier-based analysis method has proved to rescue biomarkers previously missed or unnoticed by traditional analysis showing TM4SF4 and LRRK2 are novel target candidates for lung and breast cancer, respectively.
Advanced Combustion Modelling of High BMEP Engines under Water Injection Conditions with Chemical Correlations Generated with Detailed Kinetics and Machine Learning Algorithms
Authors: Pulga Leonardo , Falfari Stefania , Bianchi Gian Marco , Ricci Matteo , Forte Claudio
Published: September 2020

Water injection is becoming a technology of increasing interest for SI engines development to comply with current and prospective regulations. To perform a rapid optimization of the main parameters involved by the water injection process, it is necessary to have reliable CFD methodologies capable of capturing the most important phenomena. In the present work, a methodology for the CFD simulation of combustion cycles of SI GDI turbocharged engines under water injection operation is proposed. The ECFM-3Z model adopted for combustion and knock simulations takes advantages by the adoption of correlations for the laminar flame speed, flame thickness and ignition delay times prediction obtained by a detailed chemistry calculation. The latter uses machine learning algorithms to reduce the time to generate the full database while still maintaining an even distribution along the variables of interest. The results demonstrate the applicability of the proposed methodology, capable of capturing not only the thermodynamic effects of water injection but also the chemical kinetics aspects related to the mixture water dilution whose prediction is mandatory for addressing the engine design according to different goals: complying with new emission directives and limits, turbine inlet temperature constraints, minimization of the BSFC and possibly engine power increase.
Assessment and Validation of Internal Aerodynamics and Mixture Preparation in Spark-Ignition Engine Using LES Approach
Authors: Ritter Martin , Malbec Louis-Marie , Laget Olivier
Published: September 2020

A workflow for the assessment and validation of internal aerodynamics and mixture preparation in a representative high-tumble optical engine using Large Eddy Simulation with the commercial code CONVERGETM is proposed. First, the prediction of the aerodynamic movement in the engine is compared to Particle Image Velocimetry (PIV) measurements. The global velocity fields and position of the center of the tumble for the average experimental and simulation cycles are compared, showing a very good match of the global behavior. The cycle to cycle aerodynamic variability is investigated thanks to velocity profiles, showing that the simulated cycles feature comparable velocity fluctuations to the experiments. In a second part, to account for Direct Injection (DI), a Lagrangian spray modeling approach is used to take into account the injection process. Experimental spray penetration data are used for the calibration of the spray models, leading to a faithful representation of the spray. Mixture preparation in the engine is then assessed, comparing the fuel air equivalence ratio of the LES in the central plane to LIF diagnostics. This qualitative comparison shows a good prediction of the evolution of the position of the fuel-rich areas and overall mixing during the compression stroke. The cycle to cycle variability of the mixing process is found comparable to the experiments, though underestimated. An evaluation of this methodology is given and the next steps towards combustion computations are discussed.
Computational Study of a Multiple Fuel Injector Concept under High-Load and High-EGR Conditions
Authors: Babayev Rafig , Nyrenstedt Gustav , Johansson Bengt
Published: September 2020

A new concept utilizing multiple fuel injectors was proven effective at reducing heat transfer losses by directing spray plumes further away from the combustion chamber walls. In this concept, two injectors are mounted close to the rim of the piston bowl and point in opposite directions to generate swirling in-cylinder bulk motion. Moreover, a new flat-bowl piston design was also proposed in combination with the multiple fuel injectors for even larger improvements in thermal efficiency. However, all tests were performed at low-to-medium load conditions with no significant EGR. Modern engine concepts, such as the double compression-expansion engine (DCEE), have demonstrated higher thermal efficiency when operated at high-load conditions with a large amount of EGR for NOx control. Thus, this study aims to assess the effectiveness of the multiple-fuel-injector system under such conditions. In this study, a number of 3-D CFD simulations are performed using the RANS technique in CONVERGE. The computational domain is based on the modified Volvo D13 engine geometry that is used as a combustor unit of the DCEE. The results of this study show that the injection strategies used previously with the multiple-fuel-injector concept perform poorly at high-load conditions due to inadequate mixing. Moreover, the flat-bowl piston design proposed previously does not seem to improve heat transfer losses at these conditions. Thus, several alternative piston bowl designs are investigated, some of which are shown to reduce heat losses and improve mixing. Finally, a number of perspective strategies are recommended to be implemented with the multiple-fuel-injector concept for efficiency maximization.
Towards Developing an Unleaded High Octane Test Procedure (RON>100) Using Toluene Standardization Fuels (TSF)
Authors: Hoth Alexander , Manchiraju Ravi , Andretti Christopher , Sinur Robert , Kolodziej Christopher P.
Published: September 2020

An increase in spark-ignition engine efficiency can be gained by increasing the engine compression ratio, which requires fuels with higher knock resistance. Oxygenated fuel components, such as methanol, ethanol, isopropanol, or iso-butanol, all have a Research Octane Number (RON) higher than 100. The octane numbers (ON) of fuels are rated on the CFR F1/F2 engine by comparing the knock intensity of a sample fuel relative to that of bracketing primary reference fuels (PRF). The PRFs are a binary blend of iso-octane, which is defined to an ON of 100, and n-heptane, which represents an ON of 0. Above 100 ON, the PRF scale continues by adding diluted tetraethyl lead (TEL) to iso-octane. However, TEL is banned from use in commercial gasoline because of its toxicity. The ASTM octane number test methods have a “Fit for Use” test that validate the CFR engine’s compliance with the octane testing method by verifying the defined ON of toluene standardization fuels (TSF). The RON test method defines TSFs in the range of 65.1 RON to 113.0 RON with blends of toluene, n-heptane, and iso-octane. Since TSFs do not contain TEL, they could potentially be used as bracketing reference fuels instead of leaded PRFs beyond RON 100. In this work, multiple CFR engines performed “Fit for Use” tests per the RON test method (ASTM D2699) and the TSF ratings closely correlated to their defined RON values without the need of intake air temperature tuning. In the next step, TSFs were used as non-leaded reference fuels to rate the RON of neat methanol, ethanol, iso-propanol, iso-butanol, ethyl acetate, and diisobutylene, all of which have a RON exceeding 100. These same fuels were tested on a separate CFR engine per the official ASTM D2699 RON test method with leaded PRFs. Their TSF-based RON ratings were found to be within the variations of RON values reported in the literature and closely matched with their standard RON rating using leaded reference fuels. Therefore, octane ratings of fuels beyond RON 100 with TSFs as reference fuels proved to be one viable pathway to rate fuels >100 RON without the need for leaded reference fuels.
Research of Fuel Components to Expand Lean-limit in Super Lean-burn Condition (Part II)
Authors: Naiki Taketora , Obata Ken , Watanabe Manabu
Published: September 2020

Thermal efficiency can be improved with a super lean-burn. In a super lean-burn engine, combustion takes place at lower temperatures, meaning lower energy losses and much greater thermal efficiency.

In Part I (presented at PF&L 2019) [1], we studied the effects of various fuels on the lean limit in super lean-burn conditions. We found that the lean limit could be greatly extended and thermal efficiency improved with the right combination of engine technology and fuel technology. We also found that the lean limit closely linked to the duration from start-of-spark discharge to CA10, and that substances which shorten this duration extends the lean limit.

In this study, we evaluated the effects of hydrocarbons closer in composition to commercial gasoline on the lean limit and found that at the specific components, the lean limit could be much higher than that with commercial gasoline. We also studied the lean limit extension mechanism by focusing on autoignition.
Advanced Intra-Cycle Detection of Pre-Ignition Events through Phase-Space Transforms of Cylinder Pressure Data
Authors: Kaul Brian , Finney Charles , Stiffler Rachel , Drallmeier James
Published: September 2020

The widespread adoption of boosted, downsized SI engines has brought pre-ignition phenomena into greater focus, as the knock events resulting from pre-ignitions can cause significant hardware damage. Much attention has been given to understanding the causes of pre-ignition and identify lubricant or fuel properties and engine design and calibration considerations that impact its frequency. This helps to shift the pre-ignition limit to higher specific loads and allow further downsizing but does not fundamentally eliminate the problem. Real-time detection and mitigation of pre-ignition would thus be desirable to allow safe engine operation in pre-ignition-prone conditions. This study focuses on advancing the time of detection of pre-ignition in an engine cycle where it occurs. Phase space transforms through time-delay embedding of cylinder pressure and principal component analysis were applied to same-cycle detection of pre-ignition and shown to enable detection on the order of a crank degree earlier than deviation in cylinder pressure can be identified through direct statistical observation of the pressure data. Additionally, it appears that the deviation of the trajectory in phase space may offer the opportunity to extend this method to further extend the detection window and allow more time for mitigation actions to occur.
Holistic Engine and EAT Development of Low NO
X
and CO
2
Concepts for HD Diesel Engine Applications
Authors: Kovacs David , Mennig Marian , Rezaei Reza , Bertram Christoph
Published: September 2020

The latest legislative tendencies for on-highway heavy duty vehicles in the United States such as the feasibility assessment of low NOX standards of CARB or EPA’s memorandum forecast further tightening of the NOX emissions limits. In addition, the GHG Phase 2 legislation and also phased-in regulations in the EU enforce a continuous reduction in CO2 emissions resp. fuel consumption. In order to meet such low NOX emission limits, a rapid heat-up of the exhaust after-treatment system (EATS) is inevitable. However, the required thermal management results in increased fuel consumption, i.e. CO2 emissions as shown in numerous previous works also by the authors. A NOX-CO2 trade-off for cumulative cycle emissions can be observed, which can be optimized by using more advance technologies on the engine and/or on the EATS side.

In the present study a systematic investigation is carried out by means of model-based holistic approach targeting the definition of a high efficiency engine layout and optimal thermal management calibration. First, the potentials of combustion process optimization (compression ratio, peak firing pressure) and of turbocharger efficiency increase are quantified aiming engine efficiency increase. Afterwards, using holistic engine and EAT concept development approach, conventional and advanced EATS layouts are tested. The advanced EATS layout consist of a close-coupled dual-stage SCR system. In order to explore the benefits of each layouts, the engine heat-up calibrations are varied and the resulting, cumulative NOX-CO2 emissions of the investigated cycle are compared and evaluated. Multiple improvement measures for both engine and EAT system are discussed and an outlook of future powertrain concepts is given.
Development of an Engine Test to Rate the EGR Deposit Formation
Propensity of Fuels in Light-Duty Diesel Engines
Authors: Williams Rod , Cook Stephen , Woodall Keith , Clayton Christopher , Gee Michael , Mulqueen Simon , Reid Jacqueline , Rimmer John , Ross Alan
Published: September 2020

Exhaust Gas Recirculation (EGR) is employed in diesel engines to reduce
engine-out NOx. Carbon-containing deposits form in the EGR systems of modern
diesel engines as the particulate matter, hydrocarbons and other entrained
species deposit from the exhaust gas flow as it cools. Much work has been done
by Original Equipment Manufacturers (OEMs) to reduce deposits and mitigate their
effects by optimized dimensioning of EGR coolers and valves, introduction of EGR
cooler bypass for use in the most sensitive cold conditions and experimenting
with oxidation catalysts upstream of the EGR system. Nevertheless, deposits
forming in the high-pressure Exhaust Gas Recirculation (HP-EGR) systems of
modern diesel engines can sometimes lead to a number of problems including
emissions and fuel consumption deterioration, poor performance and drivability,
as well as breakdowns. An engine test method has been developed to enable the
impact of fuel on deposits in the HP-EGR system to be studied. This paper
describes the work undertaken in the test development and initial fuel effects
testing to prove the discriminatory power of the method. In the test method a
4-cylinder light-duty diesel engine of 1.6L displacement runs at conditions
conducive to EGR deposit formation over 24 hours and the impact of fuels on
deposit formation is determined through weighing of the EGR system components
before and after the test. Initial tests comparing a B7 representative of
European EN590 diesel fuel and a Fischer-Tropsch Gas-to-Liquid (GTL) gasoil fuel
showed that 72% less deposit formed with GTL than with B7. This work provides a
foundation for further study of fuel effects on EGR deposits.
Low-Pressure Injection of Water and Urea-Water Solution in Flash-Boiling Conditions
Authors: Kapusta Łukasz Jan , Rogoz Rafał , Bachanek Jakub , Boruc Łukasz , Teodorczyk Andrzej
Published: September 2020

The flash-boiling effect in sprays has been shown to have the capability to decrease droplet diameters and spray penetration, as well as improve the vaporization process in gasoline direct injection systems. It has also been shown that in certain conditions, the effect on spray penetration can be the opposite. Under a high degree of overheating the spray collapse effect may appear and lead to increased spray penetration - flare flash boiling. Moreover, when the boiling is already strongly present in the nozzle it may lead to flow choking. Thus, the process is difficult to be controlled. While most studies so far have focused on high-pressure direct injection systems, we investigate the process in a low-pressure system to verify if the effects observed in high-pressure systems will be similar. The study was performed on two liquids, water and a urea-water solution, to limit any individual substance’s effects on the results and to improve the practical importance of the study. The results showed no increased penetration in any of the flash-boiling cases, although at the highest considered temperatures the two plumes tend to form a single spray cloud. Although the characteristics were similar for both studied liquids, in certain measurement conditions the differences in almost all analysed spray parameters were considerable. Moreover, the study has shown that the flash-boiling effect can be considered as an effective way to improve jet and droplet break-up while avoiding a pressure increase in low-pressure injection systems.
Durability Tests of Gaskets in Biofuels Environment
Authors: Rogula Janusz
Published: September 2020

The production of biofuels to means of transport allows the additional development and the full maintenance of the agricultural sector. The biofuel of II generation may be produced with usage of waste fats and oils. That biofuel is total renewable source of energy. The properties of tested new biofuels were described. Their influence on pipes and especially gaskets and gasket materials during durability tests was determined.

Gasket materials were tested in accordance with DIN 28090-3: 2014-11 and DIN28091-2. During 1000 hours of tests at 353 K, the weight loss of the biofuel and the change in elongation (tensile stress) of the flange bolts were measured. Fuel leakage rate was calculated.

The gaskets were checked and no delamination was observed.

The value of volatile biofuels emission after 1000 hours of testing was less than allowed in DIN Standard. Fuel leakage rate was also lower too. The main conclusion of this research was the suggestion that the gasket materials used may be allowed for contact with diesel with ethyl esters and diesel with methyl esters and ethanol named BIOXDIESEL.
Injection Strategy and EGR Optimization on a Viscosity-Improved Vegetable Oil Blend Suitable for Modern Compression Ignition Engines
Authors: Hunicz Jacek , Beidl Christian , Knost Friedemar , Münz Markus , Runkel Jürgen , Mikulski Maciej
Published: September 2020

To comply with the ambitious CO2 targets of the European Union, greenhouse gas emissions from the transport sector should be eliminated by 2050. Incremental powertrain improvement and electrification are only a part of the solution and need to be supplemented by carbon-neutral fuels. Due to the high technology readiness level, biofuels offer a short-term decarbonization measure. The high process energy demand for transesterification or hydrotreating however, hinders the well-to-wheel CO2 reduction potential of current market biodiesels. An often-raised, economically and energetically feasible alternative is to use unprocessed oils with viscosity and cold-properties improvers instead. The present work investigates the suitability of one such biofuel (PlantanolTM) for advanced common rail engines operating in a partially premixed compression ignition mode. Preliminary investigations are carried out on a Euro VIb light-duty car engine. The main focus is on the influence of the fuel blend on the soot/NOX emission trade-off without changing the engine control maps. Single-cylinder engine tests are then focused on the optimization potential of injection parameters and external EGR to reach optimum performance-emissions trade-off on the new fuel. The results highlight that at the factory map setting, without EGR, biofuel offers slightly reduced thermal efficiency with respect to diesel, as a joint effect of retarded combustion and elevated THC and CO emissions. NOX emissions are reduced by 20% at both non-EGR and to 25% EGR operation. With injection parameters optimization, the combustion phasing can be adjusted to diesel-like values while keeping the NOX reduction benefits. The tested bio-oil blend is however sensitive to EGR, where increasing the recirculation rate retards the combustion while the soot emissions increase almost five-fold over the non-EGR baseline.
Fuel Effects on Regulated and Unregulated Emissions from Three
Light-Duty Euro 5 and Euro 6 Diesel Passenger Cars
Authors: Williams Rod , Dauphin Roland , Andersson Jon , Ziman Pauline , Rogerson John , Hamje Heather
Published: September 2020

Substantial advances in European road vehicle emissions have been achieved over
the past 3 decades driven by strengthening revisions in emissions legislation
and enabled by advances in fuel, vehicle engine and emissions control
technologies. As both vehicle technology and emissions legislation in Europe
continue to evolve, Concawe has conducted a study to examine the opportunities
that fuels can provide to further reduce emissions from light-duty diesel
passenger cars. Three European diesel cars spanning Euro 5, Euro 6b and Euro
6d-TEMP emissions certification levels have been tested over the cold-start WLTC
(Worldwide harmonized Light-duty Test Cycle) with 6 fuels: an EN590-compliant B5
(petroleum diesel containing 5% biodiesel by volume), a bio-derived paraffinic
diesel, a 50:50 blend of the aforementioned fuels, a low density
petroleum-derived B5, a B30 and the same B30 additized with a high dose of
cetane number improver. Results have shown that low density fuels with high
hydrogen to carbon (H/C) ratio are capable of delivering benefits in
tank-to-wheels CO2 (carbon dioxide), CO (carbon monoxide), HC
(hydrocarbons), other greenhouse gases and NOx (oxides of nitrogen),
whereas no further benefits were measured in NH3 (ammonia) or in PN
(particle number) at the low baseline levels produced by the vehicles. Compared
to B5, B30 gave a significant increase in NOx at the tailpipe from
the Euro 5 car and engine-out from the Euro 6d-TEMP car but no tailpipe
detriments in NOx were measurable in either of the Euro 6 cars, due to the good
performance of their NOx aftertreatment devices. The latter results show that
some fuel qualities previously important to control emissions such as PN or NOx
have become less impactful with the latest engine technologies. The addition of
cetane number improver to the B30 did not reduce NOx. The findings suggest that
high H/C ratio diesel fuels could offer benefits to both emissions affecting
local air quality and to greenhouse gas emissions on a tank-to-wheels basis. The
addition of higher FAME (Fatty Acid Methyl Ester) levels to fuels can be used to
increase renewable fuel contribution resulting in no penalty in NOx emissions
from newer technology vehicles. Compatibility of these fuels with the existing
vehicle fleet would require further specific consideration.
Development of Measurement Methodology for Sub 23 nm Particle Number (PN) Measurements
Authors: Lahde Tero , Giechaskiel Barouch , Martini Giorgio
Published: September 2020

A proposal for sub-23 nm Solid Particle Number (SPN) measurement method was developed by the Particle Measurement Programme (PMP) group, based on the current SPN measurement method. In the proposal, a Particle Number Counter (PNC) having (65 ± 15)% counting efficiency at 10 nm and >90% at 15 nm (PNC10) replaces the current regulation PNC efficiency of 50±12% at 23 nm and >90% at 41 nm. Additionally, a catalytically active evaporation tube (CS) is required for sub-23 nm measurement method instead of the non-reactive evaporation tube (ET) of the current regulation. Here experimental work carried out at the JRC to address the issues of sub-23 nm SPN-measurement method is presented. The PNC10 was shown to be less dependent on the particle material than the PNC23, thus soot-like particles are still allowed for PNC-calibration. The high charging probability of soot-like particles was shown to have a low effect on PNC calibration uncertainties. The new proposed linearity test which requires that the PNC readings need to be within ±5% of the slope was here shown to be applicable. The proposal requires that Particle Concentration Reduction Factor (PCRF) at 15 nm shall be at most 100% higher than the 100 nm PCRF for the Volatile Particle Remover (VPR). The allowed variability in VPR-losses and PNC10-efficiencies of the new proposal could cause differences up to 36% when a distribution with Geometric Mean Diameter at 15 nm was simulated. Yet, for the commercial CS and ET systems with experimentally determined PCRF 15 nm to 100 nm ratios of 80% and 50% respectively, the maximum difference was 19% using PNC10. The average PCRF in the proposal is calculated as in the current regulation, with an average of PCRFs at 30 nm, 50 nm and 100 nm in order to keep the comparability with the 23 nm regulation and because the addition of the PCRF at 15 nm did not improve the accuracy.