bluuebunny/crossref_metadata_2025 huggingface dataset:
Parent-Directed use of Over-the-Counter Medications and Complementary and Alternative Medicine Therapies among Pediatric Patients: A Cross-Sectional Study
Authors: Seth Shreyasi , Dubey Ashok Kumar , Maheshwari Nidhi
Published: August 2023

ABSTRACT

Objective:

The use of over-the-counter (OTC) drugs and complementary and alternative medicines (CAM) as initial options by parents is common in the pediatric population. Despite the widespread use of parent-directed medication (PDM) among the pediatric population, we have scarce data in the Indian context. This study was done to assess the PDM practices and its determinants in the Indian population.

Methods:

It was a descriptive cross-sectional study assessing a representative sample of 284 parents of pediatric patients visiting the pediatrics department of a tertiary care hospital.

Findings:

Majority (64.08%; 182 out of 284) of the parents agreed to have used some form of PDM in the past 3 months. While higher socioeconomic status and having 2 or more children were associated with higher practice of PDM (P < 0.05), it was similar between educated or uneducated parents, rural or urban backgrounds, and nuclear or joint families (P > 0.05). CAM was the most commonly used option (58.12%; 161 out of 277), followed by OTC conventional allopathic medications (41.88%; 116 out of 277). Homeopathic medicines were the most preferred alternative therapy under the Alternative Medical System Category of National Centre for Complementary and Alternative Medicine. Majority of parents (71.43%; 130 out of 182) were confident that the treatment chosen could not harm the health of their children and they attributed time constraints or availability of prior prescriptions as reasons for such practice.

Conclusion:

PDM is a widespread phenomenon in the Indian pediatric population. The parents as well as the prescribers need to take a more balanced, practical, and judicious approach toward medications given to a child.
Does Serratiopeptidase prevent thoracic surgery in patients of hydropneumothorax of tubercular aetiology?
Authors: Shukla Amitabh D. , Agarwal Vaidehi
Published: August 2023

Background:

Tubercular hydropneumothorax is commonly seen in Indian hospitals. Anti-tuberculosis drugs and intercostal drainage tube (ICD) insertion are the mainstays of treatment. But many patients have to be referred to thoracic surgery for surgical management. This study aims to evaluate the role of serratiopeptidase in successful resolution of tubercular hydropneumothorax and avoidance of thoracic surgery.

Methods:

We conducted a retrospective observational cohort study on 28 patients that were admitted to extrapulmonary TB ward of our hospital. All patients were given anti-TB drugs according to national guidelines and underwent ICD tube insertion. Out of 28 patients recruited, 19 suffering severe chest pain received serratiopeptidase containing analgesic tablets and nine patients of the control group not having severe chest pain received non-serratiopeptidase containing analgesic tablets. Both groups were compared on the basis of successful ICD tube removal. The results were analysed using Chi-square statistic with Yates correction.

Results:

Of the 19 patients in the intervention group who received serratiopeptidase, 16 had successful recovery while three had to undergo thoracic surgery. Of the nine patients in the comparison group, only one had a successful recovery while the other eight had to be referred to thoracic surgery with ICD tube in situ. The outcome showed a statistically significant difference between the two groups, in terms of ICD tube removal and avoidance of thoracic surgery, with a P value of < 0.001.

Conclusion:

We conclude that the addition of serratiopeptidase to anti-tubercular drugs regimen can lead to better clinical outcomes and avoidance of thoracic surgery, in patients of tubercular hydropneumothorax.
Rapid diagnosis of TB using Aptamer-based assays for Mycobacterium tuberculosis antigens in children and adolescents
Authors: Bethu Rajesh , Mittal Hema Gupta , Sharma Tarun K. , Shulania Anuradha , Sharma Neera , Rangarajan Shmitha , Jain Prerna
Published: August 2023

Background:

Despite advances establishing microbiological evidence of tuberculosis (TB) is still a concern in children due to the limitation of availability of sample and predominance of extrapulmonary TB, there is unmet need for diagnostic tests which are low cost, rapid and sensitive and specific.

Methods:

This study evaluated the utility of aptamer-based assay for detecting mycobacterium tuberculosis antigens HspX and MPT 64 in rapid diagnosis of TB in children up to 18 years of age in a tertiary medical college. A total of 100 children were sequentially enrolled with presumptive pulmonary (n = 52 and extrapulmonary n = 48) TB based on clinico-radiological characteristics. The samples were evaluated with ALISA technique for TB antigens and compared with the results of ZN microscopy, GeneXpert and mycobacterial culture MGIT.

Results:

The enrolled children had mean age (11.7 + 4.4 years) with both pulmonary (n = 52) and extrapulmonary TB (n = 48). Our study results concluded poor results of smears (11% positivity, sensitivity: 17.7%, NPV: 42.7%) and better of GeneXpert (positivity: 42%, sensitivity of 67.4%, NPV: 65.5%) and culture (positivity 57%, sensitivity 91.9%, NPV 88.3%). HspX antigen by ALISA had comparable results (positivity: 49%, sensitivity: 62.9%; NPV: 54.9%). MPT 64 antigen by ALISA also had similar results (positivity: 45%, sensitivity: 58% and NPV 52, 3%). Sensitivity and specificity were higher in pulmonary TB compared to EPTB for both antigens. HspX antigen assay by ALISA and MPT 64 ALISA over existing microbiological diagnostic methods had additional of 13%.

Conclusion:

ALISA technique for mycobacterium antigens HspX and MPT 64 was rapid, low-cost test (1-3$/test) high sensitivity and specificity and comparable to currently available methods.
Trend analysis of asthma mortality and years of life lost from 2004 to 2019 in Southern Iran
Authors: Azarbakhsh Habibollah , Dehghani Seyed S. , Hassanzadeh Jafar , Janfada Maryam , Razeghi Ahmadreza , Mirahmadizadeh Alireza
Published: August 2023

Objective:

Asthma is a globally important non-communicable disease with major public health consequences. The aim of this study was to determine the mortality rate and years of life lost (YLL) due to asthma in southern Iran.

Methods:

All deaths due to asthma in Fars province from the electronic population-based death registration system (EDRS) were obtained. Crude mortality rate, age-standardized mortality rate, YLL and YLL rate data were calculated. The JoinPoint Regression method was used to examine the trend.

Results:

During the 16-year study period (2004-2019), 1167 deaths due to asthma occurred in Fars province among which 54.7% (638 cases) were men and 29.6% (346 cases) were in the age group of 70–79 years. Crude mortality rate of asthma had decreased by 121% and 84% in males and females, respectively from 2004 to 2019. The total years of life lost due to asthma during the 16-year study period were 7697 (0.24 per 1000 people) in men, 6882 (0.22 per 1000 people) in women. According to the join point regression analysis, the 16-year trend of YLL rate due to premature mortality was decreasing: the annual percent change (APC) was -5.6% (95% CI −8.2 to −2.9, P = 0.001) for males, −4.4% (95% CI −7.3 to −1.4, P = 0.008) for females.

Conclusion:

The trend of mortality and years of life lost due to asthma has decreased significantly during the years of study, although in some age groups, especially the age group of 45–59 years which has the highest number of years of life lost, this trend has been constant and unchanged. It is necessary to conduct other studies to investigate the possible reasons for this unchanged trend in vulnerable age groups.
Right hemi diaphragmatic eventration – A rare post SARS-COV-2 infection complication
Authors: Baby Benison P. , Mittal Neeru
Published: August 2023

Diaphragm eventration is a rare permanent abnormal elevation of diaphragmatic muscles. They are rare entities with right-sided eventration occurring rarer still. We present a case of a 69-year-old male with right-sided hemidiaphragmatic eventration and post-COVID 19 pulmonary fibrotic changes.
A case of post renal transplant PTLD of lung
Authors: Sinha Tanay , Mishra Harshita , Thomas Rosna , Karpe Sonal P. , Waghmare Siddharth , Nair Jairaj P. , Thorve Swapnil M.
Published: August 2023

Post Transplant Lymphoproliferative Disorder (PTLD) is a heterogeneous group of Lymphoid proliferative disorders that occur in patients post Hematogenous or Solid organ transplants. They are closely associated with Ebstein-Barr Virus and can range from polyclonal lesions to frank lymphomas. PTLD is usually a rare post-transplant complication, with the incidence being higher post Lung or Heart Transplantation and less commonly seen post-renal transplantation. The incidence post renal transplantation is less than 1%, with most of the cases being limited to the Gastro-Intestinal Tract and Lymph nodes, and incidence in the lungs being extremely rare. Here we present a case report of PTLD of the lung in a post-renal transplant recipient.
Incidental Histopathological Diagnosis of Tonsilar Actinomycosis: A Report of Four Cases
Authors: Samaila Modupeola Omotara , Sani Kamarudeen , Shofoluwe Nurudeen Adebola , Rimamskep Ifusumu Yirom
Published: August 2023

Actinomycosis of the tonsils is uncommon even though the causative organisms are normal commensal of the oropharyngeal tract that may colonise the tonsillar crypts with resultant infection in apparently healthy individuals. Diagnosis is often incidental in tonsillectomy specimens sent to the pathology laboratory for varied diseases. This is a 10-year study of tonsillectomy specimens diagnosed with actinomycosis. Specimens were formalin-fixed and paraffin processed and stained with haematoxylin and eosin, gromott methenamine silver and periodic acid–Schiff. Four cases of tonsillar actinomycosis were diagnosed from a total of 772 tonsillectomy specimens. Histologically, characteristic oeosinophilic granules with peripheral radial protuberances surrounded by microabscesses were seen. Tonsillar actinomycosis is often an incidental diagnosis; however, a high index of suspicion should be entertained in patients with recurrent tonsillitis and/or tonsillar hypertrophy of unknown cause.
A Comparison of Loupe-Assisted and Non-Loupe-Assisted Subinguinal Varicocelectomy
Authors: Okeke Chike John , Ojewola Rufus Wale , Jeje Emmanuel Ajibola , Tijani Kehinde Habeeb , Ogunjimi Moses Adebisi
Published: August 2023

Introduction:

Varicocele is a treatable aetiology of male infertility. Magnification with surgical loupe has been associated with improved outcome and reduced morbidity than the conventional technique without magnification.

Objective:

To compare the outcomes of two techniques of subinguinal varicocelectomy, with a surgical loupe and without.

Patients and Methods:

This was a prospective randomised hospital-based study. Forty-six patients were randomised to two arms – Group A: loupe-assisted subinguinal varicocelectomy (LASV) and Group B: open subinguinal varicocelectomy without Loupe (OSV). They all had their semen and hormonal parameters compared preoperatively and at 3 and 6 months postoperatively. Post-operative complications were also assessed. P < 0.05 was considered statistically significant.

Results:

The mean age was 38.28 ± 4.55 years with a range of 27–46 years. The mean age in Group A was 37.35 ± 4.68 and 39.22 ± 4.33 years in Group B. There was an improvement in motility, sperm count and concentration in both the groups at 3 and 6 months (P < 0.05). However, there was no difference in these parameters on comparison of the two groups at 3 and 6 months (P > 0.05). Follicle-stimulating hormone decline was significant in the OSV group at 3 and 6 months, P = 0.010 and 0.021, respectively. There was no difference in other hormonal parameters both at 3 and 6 months (P > 0.05). The pregnancy rate in each arm of study was 4.3%. All complications occurred in Group B.

Conclusion:

Both techniques resulted in improvement in seminal fluid parameters. All complications occurred in the arm that had subinguinal varicocelectomy without loupe. Loupe-assisted subinguinal varicocelectomy is safe and effective.
Burned-out Testicular Tumor Presenting as Cervical and Retroperitoneal Lymphadenopathy
Authors: Das Deepak Kumar , Majumdar Saroj Kumar Das , Barik Sandip Kumar , Mishra Pritinanda , Parida Girish Kumar , Muraleedharan Anupam , Parida Dillip Kumar , Sable Mukund Namdev , Patel Ranjan Kumar , Shahin Mohammed
Published: August 2023

A burned-out tumor of the testis is a rare clinical entity. It usually regresses spontaneously without any treatment and presents as metastasis to the retroperitoneum, mediastinum, cervical region, lungs, and liver. Clinical examination and ultrasound of the testis are pivotal to raising suspicion for the diagnosis of the burned-out tumor. Here, we report a case of a 23-year-old male who presented to us with a complaint of swelling on the left side of the neck. Biopsy from the neck mass suggested metastatic malignant mixed germ cell tumor, consistent with yolk sac tumor and embryonal carcinoma. The whole-body fluorodeoxyglucose-positron emission tomography-computed tomography suggested conglomerated left neck mass and retroperitoneal lymph node enlargement. Ultrasound of the scrotum suggested heterogeneously hypoechoic echotexture with few foci of microcalcification in the right testes. He underwent a right high inguinal orchidectomy, which showed no evidence of the tumor. The patient received four cycles of chemotherapy with bleomycin, etoposide, and a cisplatin-based combination regimen with a favorable response to the therapy. In view of residual viable disease and raised tumor markers, the patient received second-line chemotherapy with paclitaxel, ifosfamide, and carboplatin.
Increased Risk of American Tegumentary Leishmaniasis in an Urban and Rural Area of Caratinga, Brazil between 2016 and 2021
Authors: Neves Rafael L. , Ker Fabrício T. O. , Dutra-Rêgo Felipe , Rugani Jeronimo M. N. , Andrade Filho José D. , Soares Rodrigo P. , Gontijo Célia M. F.
Published: August 2023

We used spatial analysis tools to examine the epidemiological situation and spatial distribution of American tegumentary leishmaniasis in the municipality of Caratinga between 2016 and 2021. In addition, potential sandfly vectors were captured. All information used in this study was retrieved from public health archives and confirmed in the state health services databases. All cases were analyzed using Geographic Information Systems software. In addition, sandfly collections and molecular detection of Leishmania were carried out in areas with the highest number of cases. During the analyzed period, American tegumentary leishmaniasis (ATL) cases increased and remained high in the last years. The hotspots included urban areas of Caratinga city and the districts of Patrocínio of Caratinga and Sapucaia. The species Nyssomyia whitmani, Nyssomyia intermedia, and Migonemyia migonei were the most abundant species and the ITS1-polymerase chain reaction technique detected Leishmania DNA in these species. On the basis of our analyses, the urbanization of ATL in Caratinga has taken place in recent years. Because of the increase in the number of human cases and the presence of vectors, it is recommended that health authorities focus on control measures in hotspots.
Wastewater-Based Surveillance of Antimicrobial Resistance in Niger: An Exploratory Study
Authors: Ousmane Sani , Kollo Issifi A. , Jambou Ronan , Boubacar Rakia , Arzika Ahmed M. , Maliki Ramatou , Amza Abdou , Liu Zijun , Lebas Elodie , Colby Emily , Zhong Lina , Chen Cindi , Hinterwirth Armin , Doan Thuy , Lietman Thomas M. , O’Brien Kieran S.
Published: August 2023

Wastewater-based surveillance is increasingly recognized as an important approach to monitoring population-level antimicrobial resistance (AMR). In this exploratory study, we examined the use of metagenomics to evaluate AMR using untreated wastewater samples routinely collected by the Niger national polio surveillance program. Forty-eight stored samples from two seasons each year over 4 years (2016–2019) in three regions were selected for inclusion in this study and processed using unbiased DNA deep sequencing. Normalized number of reads of genetic determinants for different antibiotic classes were compared over time, by season, and by location. Correlations in resistance were examined among classes. Changes in reads per million per year were demonstrated for several classes, including decreases over time in resistance determinants for phenicols (–3.3, 95% CI: –8.7 to –0.1, P = 0.029) and increases over time for aminocoumarins (3.8, 95% CI: 0.0 to 11.4, P = 0.043), fluoroquinolones (6.8, 95% CI: 0.0 to 20.5, P = 0.048), and beta-lactams (0.85, 95% CI: 0.1 to 1.7, P = 0.006). Sulfonamide resistance was higher in the post–rainy season compared with the dry season (5.2-fold change, 95% CI: 3.4 to 7.9, P < 0.001). No differences were detected when comparing other classes by season or by site for any antibiotic class. Positive correlations were identified in genetic determinants of resistance among several antibiotic classes. These results demonstrate the potential utility of leveraging existing wastewater sample collection in this setting for AMR surveillance.
A Quasi-Dimensional Two-System Burn Rate Model for Pre-Chamber-Initiated SACI Combustion
Authors: Salerno Francesco , Kulzer Andre , Bargende Michael , Grill Michael , Burkardt Patrick , Günther Marco , Pischinger Stefan
Published: August 2023

State-of-the-art spark-ignition engines mainly rely on the quasi-hemispherical flame propagation combustion method. Despite significant development efforts to obtain high energy conversion efficiencies while avoiding knock phenomena, achieved indicated efficiencies remain around 35 - 40 %. Further optimizations are enabled by significant excess air dilution or increased combustion speed. However, flammability limits and decreasing flame speeds with increasing air dilution prevent substantial improvements. Pre-Chamber (PC) initiated jet ignition combustion systems improve flame stability and shift flammability limits towards higher dilution levels due to increased turbulence and a larger flame area in the early Main-Chamber (MC) combustion stages. Simultaneously, the much-increased combustion speed reduces knock tendency, allowing the implementation of an innovative combustion method: PC-initiated jet ignition coupled with Spark-Assisted Compression Ignition (SACI). The jets penetrating the MC establish a flame propagation combustion that – with appropriate boundary conditions – triggers a controlled volume reaction in the remaining charge. The resulting ultra-fast combustion process converges to the ideal thermodynamic constant-volume cycle leading to indicated efficiencies of >45%. However, implementing this combustion method requires precisely adjusted boundary conditions and a suitable geometrical design (e.g., compression ratio). This paper addresses the development of a fast-running quasi-dimensional burn rate model for PC-initiated SACI combustion to conduct robust design studies and complement existing testing methodologies (3D-CFD, experimental). The modeling approach considers two thermodynamic systems (PC and MC) connected through orifices. Both systems use the two-zone entrainment model for flame propagation combustion. Furthermore, the eventual MC volume reaction is modeled by a multi-pseudo-zone approach based on a distributed auto-ignition integral. The models are integrated into the so-called cylinder module developed at the Institute of Automotive Engineering Stuttgart and validated using measurement data of two single-cylinder research engines using different fuels (E100, RON95E10), loads (IMEP = 6 − 15 bar), excess air dilutions (λ = 1 − 2.8) and compression ratios (12.6 – 16.4), showing a satisfactory prediction of the burn rates and pressure curves.
An Experimental Characterization of Gasoline/Ozone/Air Mixtures in Spark Ignition Engines
Authors: Anaclerio Fabio , Saponaro Gianmarco , Mancaruso Ezio , Mazzarella Carlo , Fornarelli Francesco , Magi Vinicio , Camporeale Sergio
Published: August 2023

In this work, an ozone/air/gasoline mixture has been used as an alternative strategy to achieve a stable combustion in a spark ignition (SI) single cylinder PFI research engine. The air intake manifold has been modified to include four cells to produce ozone with different concentrations. In the research engine, various operating parameters have been monitored such as the in-cylinder pressure, temperature and composition of the exhaust gases, pressure and temperature of the mixture in the intake manifold, engine power and torque and specific fuel consumption. Experimental tests have been carried out under stoichiometric mixture conditions to observe the influence of ozone addition on the combustion process. The results show an advance and an increase of the in-cylinder pressure compared to the reference test-case, where a gasoline/air mixture is used. It is worth noting that, especially under stoichiometric condition, ozone concentration induces auto-ignition and knock. Thus, the influence of ozone on lean combustion has been investigated. In particular, the combustion process at 1400 rpm under lean conditions, with an air-fuel equivalence ratio around 2, has been tested with varying ozone concentrations. The results show a sensible reduction of misfire together with a higher laminar flame speed and improved flame stability. Indeed, the ozone addition on air/gasoline mixture reduces the CCV from 5% to 1.75% and an increase of fuel conversion efficiency. Furthermore, pollutant emissions have also been analyzed. The results show that NOx slightly increases while unburned HCs decrease with ozone concentration.
Investigation into Various Strategies to Achieve Stable Ammonia Combustion in a Spark-Ignition Engine
Authors: Uddeen Kalim , Almatrafi Fahad , Shi Hao , Tang Qinglong , Parnell Jamie , Peckham Mark , Turner James
Published: August 2023

Ammonia (NH3) is a carbon-free fuel, which could partially or completely eliminate hydrocarbon (HC) fuel demand. Using ammonia directly as a fuel has some challenges due to its low burning speed and low flammability range, which generates unstable combustion inside the combustion chamber. This study investigated the effect of two different compression ratios (CRs) of 10.5 and 12.5 on the performance of ammonia combustion by using a conventional single spark-ignition (SI) approach. It was found that at a lower CR of 10.5, the combustion was unstable even at advanced spark timing (ST) due to poor combustion characteristics of ammonia. However, increasing the CR to 12.5 improved the engine performance significantly with lower cyclic variations. In addition, this research work also observed the effect of multiple spark ignition strategies on pure ammonia combustion and compared it with the conventional SI approach for the same operating conditions. Multiple flames were generated by four spark plugs, which were mounted at equal intervals on the periphery of a customized metal liner and one additional spark plug was fitted at the top of the cylinder head. The results illustrated that adding more spark ignition sites builds higher in-cylinder pressure and temperature, which further burned the charge rapidly. This produced higher engine efficiency, lower combustion duration, and reduced cycle-to-cycle variations. Additionally, multiple spark plugs together were used to ignite a lean case of air-fuel equivalence ratio, λ: 1.2, and compare it with the stoichiometry condition of λ: 1.0. Furthermore, a Cambustion fast NO and NO2 analyzer was used to precisely record the NO and NO2 concentrations during ammonia combustion. It was observed that firing multiple spark plugs produced higher NOx emissions than the single spark plug case, considered to be due to the higher in-cylinder temperature generated by the creation of multiple flame kernels.
Experimental Investigation on the Combustion of Biogas Containing Hydrogen in a HCCI Engine
Authors: Mariani Antonio , Brequigny Pierre , Masurier Jean-Baptiste , Unich Andrea , Minale Mario , Foucher Fabrice
Published: August 2023

Biogas is a gas resulting from biomass, with a volumetric content of methane (CH4) usually ranging between 50% and 70%, and carbon dioxide (CO2) content between 30% and 50%; it can also contain hydrogen (H2) depending on the feedstock. Biogas is generally used to generate electricity or produce heat in cogeneration system. Due to its good efficiency through the rapid combustion and lean air-fuel mixture, Homogeneous Charge Compression Ignition (HCCI) engine is a good candidate for such application. However, the engine load must be kept low to contain the high-pressure gradients caused by the simultaneous premixed combustion of the entire in-cylinder charge. The homogenous charge promotes low particulate emissions, and the dilution helps in containing maximum in-cylinder temperature, hence reducing nitrogen oxide emissions. However, HC and CO levels are in general higher than in SI combustion. Moreover, HCCI engines usually require high intake temperature with values depending on compression ratio, fuel, equivalence ratio, and intake pressure.

This paper presents the results of an experimental campaign on a diesel internal combustion engine for passenger cars, modified to operate in HCCI mode. The engine was fuelled by mixtures of methane, H2, and carbon dioxide, with the aim of reproducing the composition of innovative biogas naturally containing hydrogen. The equivalence ratio was kept constant at 0.4 and the intake charge temperature and pressure have been adjusted, depending on fuel composition, to control the combustion process. For each fuel, the intake charge conditions for an optimal combustion phasing have been determined, attaining a maximum indicated engine efficiency of 40% and specific NOx emissions down to 0.1 g/kWh.
Impact of Hydrogen on the Ignition and Combustion Behavior Diesel Sprays in a Dual Fuel, Diesel-Piloted, Premixed Hydrogen Engine
Authors: Rajasegar Rajavasanth , Srna Ales , Lee Taesong
Published: August 2023

Renewably sourced hydrogen is seen as promising sustainable carbon-free alternative to conventional fossil fuels for use in hard to decarbonize sectors. As the hydrogen supply builds up, dual-fuel hydrogen-diesel engines have a particular advantage of fuel flexibility as they can operate only on diesel fuel in case of supply shortages, in addition to the simplicity of engine modification. The dual-fuel compression ignition strategy initiates combustion of hydrogen using short pilot-injections of diesel fuel into the combustion chamber. In the context of such engine combustion process, the impact of hydrogen addition on the ignition and combustion behavior of a pilot diesel-spray is investigated in a heavy-duty, single-cylinder, optical engine. To this end, the spatial and temporal evolution of two-stage autoignition of a diesel-fuel surrogate, n-heptane, injected into a premixed charge of hydrogen and air is studied using optical diagnostics. This includes high-speed cool-flame and OH* chemiluminescence imaging which serve as an indicator of low-temperature and high-temperature heat-release, respectively. A comparative analysis of the ignition inhibitive properties of hydrogen benchmarked against natural gas dual-fuel combustion from a previous study under nominally identical conditions facilitates the understanding of the underlying mechanisms driving the ignition behavior. The experimental results are complemented with zero-dimensional chemical-kinetics simulations to provide further insight on the impact of hydrogen and natural gas addition on the two-stage autoignition chemistry of diesel fuel. The imaging results and the thermodynamic analysis revealed a complex interplay of physico-chemical process including jet entrainment, end of injection enhanced mixing, and low and high-temperature fuel-chemistry in the presence of hydrogen, which jointly govern the ignition process in a dual-fuel engine.
Variable Compression Ratio Hydrogen-Fueled Homogeneous Charge Compression Ignition Engine
Authors: Nguyen Ducduy , Fernandes Renston , Turner James W.G.
Published: August 2023

Hydrogen-fueled homogeneous charge compression ignition (HCCI) engines have shown the ability to provide a cleaner and more efficient alternative to conventional fossil fuels. The use of hydrogen as a fuel has the potential to reduce greenhouse gas and promote sustainability.

In this study, a modified single-cylinder Cooperative Fuel Research (CFR) engine was utilised to operate on hydrogen in a HCCI combustion mode under various compression ratio (CR) conditions. In the experiments, the amount of hydrogen injected was adjusted at each CR to maintain the crank angle at 50% mass fraction burned (CA50) combustion phasing at 3±1 crank angle degrees after top dead center or as lean as possible. The engine speed was fixed at 600 rpm, and the impact of different intake air temperatures was also investigated.

The results indicated that as the compression ratio increases, the air-fuel ratio needs to be increased to maintain the desired CA50 value, i.e., the engine needs to operate leaner. The net indicated mean effective pressure of the engine reached a value of 2.9 bar at a compression ratio of 14 and an intake air temperature of 150OC. The effects of CR and intake temperature on engine performance metrics, such as power output and the rate of heat release, were also investigated. The experimental data showed that the intake air temperature did not have a significant effect on engine performance and power output. At a compression ratio of 16:1 and 600 rpm, the engine's indicated thermal efficiency was found to be approximately 33% across the range of intake temperatures investigated. Furthermore, the fact that the engine effectively produced zero NOx emissions under the various CR conditions tested further highlights the potential for hydrogen HCCI engines to be adopted as a cleaner and more efficient alternative to internal combustion engines using conventional fuels, provided the available range of operation is acceptable and can be made large enough for practical applications.
High Performance and Near Zero Emissions 2-Stroke H
2
Engine
Authors: Caprioli Stefano , Volza Antonello , Mattarelli Enrico , Rinaldini Carlo Alberto
Published: August 2023

The paper presents a preliminary study on a virtual 2-stroke 3-cylinder 0.9 L DI SI supercharged engine running on Hydrogen (H2), able to meet both high performance targets and ultra-low emissions limits (NOx<20 ppm). Combustion is similar to a conventional 4-stroke H2 DI engine, while the design of the cylinder and the actuation law of both intake and exhaust valves are specifically optimized for the 2-stroke cycle. In comparison to a more conventional 2-stroke loop scavenged engine, with piston-controlled ports, the use of poppet valves enables a more flexible control of the gas exchange process and to maintain the same design of a 4-stroke engine for pistons, cylinders block, crankcase and lubrication system. On the other hand, it is more difficult to avoid the short-circuit of the fresh charge, while permeability of the valves becomes quite critical at high engine speed. Therefore, particular care was devoted to the optimization of the intake and exhaust ports geometry, as well as to the valves actuation law. While the development of the scavenging system was mainly supported by CFD-3D simulation, the optimization of the supercharging system is driven by 1D analyses (by GT-Power). Three different supercharging configurations have been analyzed, with different levels of complexity, performance and cost: compact mechanical supercharger, controlled by a by-pass valve; variable geometry turbocharger, assisted by a mechanical supercharger and controlled by a by-pass valve; variable geometry turbocharger, assisted by an electric supercharger. The 1D engine model of the 2-stroke engine is derived as closely as possible from the experimentally calibrated model of a 4-stroke H2 prototype. In particular, the virtual engines share the setup of the predictive combustion and emissions models.
Experimental Combustion Analysis in a Gasoline Baseline Hydrogen-Fueled Internal Combustion Engine at Ultra-Lean Conditions
Authors: Ramalho Leite Caio , Laignel Mathieu , Brequigny Pierre , Borée Jacques , Foucher Fabrice
Published: August 2023

Hydrogen-fueled internal combustion engines (H2ICEs) have emerged as a promising technology for reducing greenhouse gas emissions in the transportation sector. However, due to the unique properties of hydrogen, especially under ultra-lean conditions, the combustion characteristics of hydrogen flames differ significantly from those of conventional fuels. This research focuses on evaluating the combustion process and cycle-to-cycle variations (CCVs) in a single-cylinder port-fuel injection H2ICE, as well as their impact on performance parameters. To assess in-cylinder combustion, three indicators of flame development are utilized and compared to the fundamental properties of hydrogen. The study investigates the effects of various factors including fuel-air equivalence ratio (ranging from 0.2 to 0.55), engine load (IMEP between 1 and 4 bar), and engine speed (900 to 1500 rpm). The analysis aims to understand the behavior of the flame initiation phase, which refers to the time from ignition to 10% of the mass fraction burned, as it is found to be the most sensitive period of combustion duration in H2ICEs with respect to the fuel-air equivalence ratio. The research reveals that within a wide range of equivalence ratios, there is minimal variability in combustion. The study also discusses the characteristics of the flame at ignition timing, considering the influence of factors such as turbulence and thermodiffusive instabilities. To aid in the analysis, 0D/1D engine simulations are employed, providing valuable insights into the underlying mechanisms shaping the flame behavior.
Efficiency-Biased Design of an H2-Fueled Internal Combustion Engine for Heavy and Challenging Applications
Authors: Koerfer Thomas
Published: August 2023

This publication outlines FEV’s engineering approach and the associated process steps for efficiency optimization of the entire powertrain definition for various commercial applications, from light-duty vehicles to heavy long-haul trucks, with particular emphasis on the most important use cases. A focus is on the crucial trade-off between attractive transient drivetrain performance and the pursuit of ultra-low, near zero tailpipe pollutant emissions. The applied measures, ranging from minimized mechanical friction and reduced losses to on-demand support by different boosting technologies, different types of H2 injection and mixture formation (external and internal), and different exhaust gas aftertreatment layouts, are thoroughly evaluated and investigated using FEV’s dedicated H2-ICE simulation tool chain. This enables the specification of satisfactory H2-ICE based powertrain solutions for a wide range of use cases in the commercial vehicle sector. This publication outlines FEV’s engineering approach and the associated process steps for optimization of the entire powertrain definition for various commercial vehicle applications, from light trucks to heavy long-haul trucks, with particular emphasis on the most important use cases. A focus is on the crucial trade-off between beneficial transient drivetrain performance and the pursuit of ultra-low, near zero tailpipe pollutant emissions. The applied level of support from different boosting technologies, different types of H2 injection and mixture formation (external and internal), and different exhaust gas aftertreatment layouts is thoroughly evaluated and investigated using FEV’s dedicated H2 ICE simulation tool chain. This enables the specification of satisfactory H2-ICE based powertrain solutions for a wide range of use cases in the commercial vehicle sector.
Impact of Splitting n-Dodecane Pilot Injection on Ammonia RCCI Engine
Authors: Rousselle Christine Mounaim , Brequigny Pierre , Dupuy Anthony
Published: August 2023

The increased interest in ammonia as a hydrogen carrier and a carbon-free fuel for combustion applications continues to present several challenges to address. Moreover, the high auto-ignition temperature (925 K) for ammonia limits its use in compression ignition engines because excessively high compression ratio are required. One way to retrofit diesel engine is to help the ignition by injecting a pilot injection of reactive fuel, like diesel or biodiesel. In this study, the ammonia engine ignited by a dodecane pilot injection is investigated with a maximum ammonia energy share (until 98.5%). The effect of split diesel injection strategy in two-steps under medium load operating conditions is studied as a function of ammonia/air equivalence ratio. Splitting this injection reduces NOX, CO, UHC and unburnt NH3 emissions at the exhaust, even it remains above the recommended emissions limit, especially at stoichiometric or slightly rich ammonia/air mixture. Not evident tendencies can be drawn about the improvement of GHG reduction (i.e. N2O and CO2) by splitting the diesel pilot injection. However, a strategy when the pre and the main injections being set closer to TDC, proves to be the best configuration due to the improvement of the combustion process, with a minimum diesel energy amount.
Sustainability of Future Shipping Fuels: Well-to-Wake Environmental and Techno-Economic Analysis of Ammonia and Methanol
Authors: Tripathi Shashwat , Gorbatenko Inna , Garcia Antonio , Sarathy Mani
Published: August 2023

The transportation industry has been scrutinized for its contribution towards the global greenhouse gas emissions over the years. While the automotive sector has been regulated by strict emission legislation globally, the emissions from marine transportation have been largely neglected. However, during the past decade, the international maritime organization focused on ways to lower the emission intensity of the marine sector by introducing several legislations. This sets limits on the emissions of different oxides of carbon, nitrogen and sulphur, which are emitted in large amounts from heavy fuel oil (HFO) combustion (the primary fuel for the marine sector). A 40% and 70% reduction per transport work compared to the levels of 2008 is set as target for CO2 emission for 2030 and 2050, respectively. To meet these targets, commonly, methanol, as a low-carbon fuel, and ammonia, as a zero-carbon fuel, are considered. But for the well-being of the marine ecosystem, nitrogen and sulphur oxides, emitted from ammonia combustion, are more harmful due to their acidification and eutrophication impacts. Thus, the evaluation of the emission impact and the production cost must be done for the different production pathways of both fuels to estimate the most efficient way for a sustainable transition of marine transportation. Therefore, in this study, a well-to-wake enviromental and techno-economic analysis of methanol and ammonia is done to evaluate the most feasible pathway to meet those targets. Results show that, despite methanol’s carbon-based fuel nature, it is a more sustainable option for the shipping sector in terms of meeting the emission reduction targets as well as having a lower impact on the hydrosphere.
Statistical Treatise on Critical Biodiesel (B100) Quality Properties in the United States from 2004-2022
Authors: McCormick Robert , Alleman Teresa , Nelson Richard
Published: August 2023

The quality of neat biodiesel (B100) is critical for ensuring biodiesel blends used in diesel-powered vehicles do not adversely impact engine performance. In the United States, B100 is required to meet ASTM International’s purity and fuel property requirements in D6751, “Standard Specification for Biodiesel Fuel Blend Stock (B100) for Middle Distillate Fuels.” Here we review the development of this standard for the different grades of B100. The BQ-9000 program, which currently covers over 90% of U.S. and Canadian production volumes, is also described. Engine and original equipment manufacturers have expressed a desire for credible, third-party data on values of various ASTM B100 properties in the commercial market to inform their efforts to address future emissions and durability requirements. To address this need, the National Renewable Energy Laboratory published data from analysis and testing of monthly samples from BQ-9000 producers from calendar years 2017–2022, resulting in 300–500 data points (i.e., individual fuel samples) per year. These data and a statistical evaluation of properties including the average, mean, standard deviation, and 95th or 5th percentile are presented. The results show very consistent and high-quality B100 produced in this time frame. Additionally, we review the results of earlier quality surveys conducted in the United States between 2004 and 2011, revealing how quality has changed over time in response to ASTM standard revisions, as well as the significant overall improvement in quality for modern biodiesel production.
1-D Numerical Model of a Spark Ignition Engine Fueled with Methanol for Off-Grid Charging Stations
Authors: Perrone Diego , Castiglione Teresa , Falbo Luigi , Bova Sergio , D'Epiro Clino
Published: August 2023

The road transportation sector is undergoing significant changes, and new green scenarios for sustainable mobility are being proposed. In this context, a diversification of the vehicles’ propulsion, based on electric powertrains and/or alternative fuels and technological improvements of the electric vehicles charging stations, are necessary to reduce greenhouse gas emissions. The adoption of internal combustion engines operating with alternative fuels, like methanol, may represent a viable solution for overcoming the limitations of actual grid connected charging infrastructure, giving the possibility to realize off-grid charging stations. This work aims, therefore, at investigating this last aspect, by evaluating the performance of an internal combustion engine fueled with methanol for stationary applications, in order to fulfill the potential demand of an on off-grid charging station. In addition, the possibility to recover the thermal power from the exhaust gas for cogeneration applications is also investigated. The internal combustion engine is a turbocharged spark ignition with a 4.5 liter displacement, which develops a maximum rated power of 100 kW between 1500 and 2500 rpm. A 1-D numerical model was developed using the AVL-boost software to evaluate the main performance at different engine speeds and spark advances in terms of brake and thermal power, efficiency, specific fuel consumption and pollutant emissions. Model validation was carried out with literature data on a SI single cylinder engine. Afterwards, a multi-objective optimization was performed to define the spark advance that guarantees a suitable trade-off between the brake power, the thermal power recovered by the engine and NOx emissions. Results show that methanol ensures considerable improvements in terms of performance with respect to gasoline. In particular, enhancements of 7.4% and 10.3% for the maximum brake torque and brake thermal efficiency were recorded, respectively. An optimal spark advance of 10°CA was selected as optimal value for the turbocharged spark ignition engine since it guarantees the maximum thermal power recovered from the exhaust gas, the minimum specific NOx emissions and a brake power slightly lower than the maximum value.
Virtual Development of Control Coordinator for Engine and Aftertreatment Architecture Equipped with Diesel Fuel Burner
Authors: Pozzi Chiara , Ciaravino Claudio , Donniacuo Antonio , Ferreri Paolo , Previtero Giuseppe , Chen Federico , Totaro Nicola , Mital Rahul
Published: August 2023

Heating devices are effective technologies to strengthen emission robustness of AfterTreatment Systems (ATS) and to guarantee emission compliance in the new boundaries given by upcoming legislations. Moreover, they allow to manage the ATS warm-up independently from engine operating conditions, thereby reducing the need for specific combustion strategies. Within heating devices, an attractive solution to provide the required thermal power without mandating a 48V platform is the fuel burner. In this work, a model-based control coordinator to manage the interaction between engine, ATS and fuel burner device has been developed, virtually validated, and optimized. The control function features a burner model and a control logic to deliver the needed amount of thermal energy, while ensuring ATS hardware protection. The coordinator has been optimized and validated through the virtual test campaign: the developed control function and a complete ATS model were integrated in the simulation environment, while different experimental engine out traces were used as input. By means of this tool, a preliminary emission performance assessment has been carried out comparing baseline ATS (Euro6d full capable) and a burner-equipped ATS; by several loops, an optimal burner strategy that minimizes tail-pipe emission was selected as well. Once the control design was deemed satisfactory, a real ATS equipped with a burner device was experimentally tested at engine dyno. The experimental campaign allowed to test the control design and assess the predictive capability of the virtual model in terms of tailpipe emission. It was found that the virtual model allowed to properly develop the control functions and to predict the emission reduction trend. From a methodology perspective, virtualization is confirmed to be a cost- and time-effective instrument to develop control logics and first-attempt calibration for their operative strategy.
Analysis of a Modern Twin-Spool Supercharged Gas Turbine Engine Concept for Hybrid Vehicle Applications
Authors: Babaji Badamasi , Kenkoh Kesty Yong , Turner James W.G.
Published: August 2023

This paper presents results from an extended analysis of a supercharged gas turbine concept initially proposed by Ford Motor Company in the 1960s. The concept was augmented through individual component improvements and utilization of new technologies developed over the 60 years since the inception of the original concept, known as the Ford “Type 704” engine. The model was constructed using Aspen Plus software and was validated in terms of the drive shaft power and brake-specific fuel consumption. The relative errors versus the data published by Ford were 0.06% in BSFC and 0.7% for shaft power and total fuel mass flow. The BTE matched the original Ford values to three decimal places. Having validated the model, a series of modernization steps were undertaken to bring the technology from six decades ago to a modern level. The model 704 has two spools, each connecting a compressor to its driven turbine with a separate power turbine positioned between the two other turbines. This configuration was modified by merging the low-pressure turbine with the power turbine and incorporating an electric machine on that spool for power take-off. Additionally, a second electric machine was added to the high-pressure spool, and the turbines were reconfigured to have an equal expansion ratio. The process resulted in a 64% relative improvement in BTE and a 39% reduction in BSFC while using the original turbine inlet temperature of 1200K. Recent improvements in material sciences suggest it is reasonable to go beyond this initial temperature limit, and therefore, a sensitivity analysis was carried out by varying the temperature up to 2000K. Furthermore, the effects of having different turbine inlet temperatures for the turbines after the two combustion chambers were investigated (in contrast to the Ford approach of maintaining the same inlet temperature for both turbines). By assuming a modern turbine inlet temperature of 1350K, the modernized Ford 704 has a BTE of 45.4% and a BSFC of 184.2 g/kWh. This represents an 87% improvement in BTE and a 47% reduction in BSFC in comparison to the data published by Ford. The result of the study has highlighted the capability of modern technology to simplify the complex Ford 704 engine model while improving efficiency and flexibility and perhaps demonstrating a route to a prime mover in a series hybrid application.