Study on Dual-spark Ignition Rapid Combustion Characteristic of Opposed-piston Two-stroke GDI Engine

AbstractThe mixture formation and combustion process of an opposed-piston two-stroke (OPTS) gasoline direct injection (GDI) engine was carried out by numerical simulation. The effects on in-cylinder combustion and engine performance in different ignition ways of dual-spark ignition have been compared and analyzed. The dual-spark ignition system were installed on cylinder liner could make the in-cylinder combustion more stable and faster. It was benefit for increasing the thermal efficiency and avoiding the knock. Compared with single-spark ignition, dual-spark ignition could shorten flame propagation distance and accelerate flame propagation. Compared with single-spark ignition and synchronous dual-spark ignition models, the rapid combustion period of asynchronous ignition model was shorter, which was helpful to fast burning. In 6000r/min and 15kW full load case, the best ignition angle step of asynchronous ignition was about 10° crank angle (CA). When the initial ignition angle was the same, the ignition angle step of asynchronous ignition was smaller and the antiknock was worse

Performance Evaluation and Control Strategy Comparison of Supercapacitors for a Hybrid Electric Vehicle

Electrification of powertrain system is a great technical progress of traditional vehicle, leading to a significant reduction of fuel consumption and emission pollution. Energy storage system (ESS) normally consisting of batteries is a key component of an electric vehicle or hybrid electric vehicle. An ESS can recover braking energy during the regenerative braking process. Currently, lithium-ion batteries are the main energy storage device due to their high energy density. However, sometimes, a sudden large increase of operation current is required during acceleration or regenerative braking processes, which will jeopardize the operation life of batteries. A supercapacitor takes advantage of high power density and can tolerate large current in a short time. Application of supercapacitor in an ESS can reduce the peak current of batteries effectively, and the life time of batteries can be extended. Meanwhile, the braking energy can also be recovered sufficiently. Supercapacitors can be used solely in some hybrid electric vehicles. In this chapter, the application of supercapacitors in electric vehicles or hybrid electric vehicles is reviewed briefly. Then, the performance of a series hybrid transit bus, which uses a compressed natural gas engine and supercapacitors as power sources, is analyzed

Knock Suppression of a Spark-Ignition Aviation Piston Engine Fuelled with Kerosene

Spark-ignition (SI) engine has a high power density, making it suitable for unmanned aerial vehicles. Normally, gasoline fuel with a high octane number (ON) is used for a spark-ignition engine. However, gasoline fuel is easy to be evaporated and has a low flash point which is unsafe for aviation engines. Kerosene with a high flash point is safer than gasoline. In this chapter, the combustion characteristics of kerosene for a spark-ignition aviation piston engine are analyzed. A three-dimensional (3D) model is setup, and the combustion process of the engine fuelled with kerosene is simulated. Later, the knock limit extension by water injection is evaluated experimentally. The results indicate that water injection can suppress the knock of SI engine with kerosene in some extent and the output power can be improved significantly

Changes in glycosylated proteins in colostrum and mature milk and their implication

IntroductionGlycosylation is one of the essential post-translational modifications that influences the function of milk proteins.MethodsIn the present study, 998 proteins and 764 glycosylated sites from 402 glycoproteins were identified in human milk by TMT labeling proteomics. Compared to human milk proteins, the glycoproteins were mainly enriched in cell adhesion, proteolysis, and defense/immune process.ResultsThe abundance of 353 glycosylated sites and their 179 parent proteins was quantified. After normalization to their parent protein’s abundance, 78 glycosylated sites in 56 glycoproteins and 10 glycosylated sites in 10 glycoproteins were significantly higher in colostrum and mature milk, respectively. These changed glycoproteins were mainly related to host defense. Intriguingly, one glycosylated site (Asp144) in IgA and two glycosylated sites (Asp38 and Asp1079) in tenascin are significantly upregulated even though their protein abundance was downregulated during lactation.DiscussionThis study helps us figure out the critical glycosylated sites in proteins that might influence their biological function in an unbiased way

Comparative Genomic Analysis of Latilactobacillus curvatus and L. sakei

In this study, the genomes of 19 Latilactobacillus curvatus and 40 L. sakei strains were comparatively analyzed. Average nucleic acid identity (ANI) and genome-wide colinearity indicated that the genomes of L. curvatus and L. sakei had weak nucleotide sequence homology, allowing them to be used as indicators to distinguish the two species. Pangenomes for these species were constructed, whose core gene functions were annotated. The results showed that the core genomes of L. curvatus and L. sakei were mainly involved in their basic metabolism. Analysis of individual genomes of the strains revealed that 1) both L. curvatus and L. sakei contained a wide range of genes encoding glycoside hydrolases, which are abundant genetic resources for catabolizing and metabolizing dietary fiber such as polysaccharides, lactose utilization, and lignocellulose; 2) antibiotic resistance genes were annotated in the genomes of three strains, which originate from horizontal gene transfer; 3) the unique arginine deiminase pathway of L. sakei, the serine dehydratase and guanine deaminase pathways of L. curvatus, and the glutamate decarboxylase pathway of several strains were identified, revealing that the acid tolerance mechanisms of these two species are different; and 4) genes encoding cold stress proteins were discovered, which endow the two species with good cold processing properties. Moreover, the genomes of some L. sakei strains contained gene clusters related to the biosynthesis of lactocin S and condensin. In conclusion, this study established taxonomic criteria for the two species and information on individual differences between their strains, which will provide a basis for the study of the physiological, biochemical, molecular genetic mechanisms of L. curvatus and L. sakei and their industrial applications

The efficacy and prognosis analysis after stereotactic body radiotherapy for multiple primary early-stage lung cancer

Background and purpose: More and more patients with multiple primary early-stage lung cancer are choosing to receive stereotactic body radiation therapy (SBRT), and this study aimed to retrospectively analyze the efficacy and prognostic factors of SBRT. Methods: In this study, patients who underwent SBRT at Shanghai Chest Hospital, Shanghai Jiao Tong University School of Medicine from August 2014 to December 2020 and who met the inclusion criteria were included. Patients with multiple primary early-stage lung cancer were examined for efficacy and prognostic factors. After using propensity score matching (PSM), the difference in efficacy of SBRT between single and multiple primary early-stage lung cancer was observed. Results: This study included 241 early-stage lung cancer patients with SBRT, including 94 patients with multiple primary early-stage lung cancer. The 3- and 5-year local control rate (LC), progression-free survival (PFS) and overall survival (OS) were 87.1% and 71.3%, 84.0% and 66.9%, 93.3% and 79.3% in multiple primary early-stage lung cancer, respectively. Patients with multiple primary early-stage lung cancer did not experience any grade 3 or higher pulmonary toxicity with an overall toxicity incidence of 54.3%, and grade 2 toxicity occurred in 24 patients (25.5%). There was a total of 18 (19.1%) recurrences, and there were 3 (3.2%), 1 (1.1%), 12 (12.7%) and 2 (2.1%) patients with multiple primary early-stage lung cancers who experienced local recurrence, regional recurrence, distant metastasis and uncertain death, respectively. Patients with multiple primary early-stage lung cancer and those with single primary early-stage lung cancer had significant differences in clinical features prior to PSM. After PSM, there were 56 patients with multiple primary early-stage lung cancer and 56 patients with single primary early-stage lung cancer, and there was no statistically significant difference in LC (P = 0.291), PFS (P = 0.954) and OS (P = 0.880). Age≥70 years was an independent risk factor for OS of multiple primary early-stage lung cancer, according to an analysis of the prognostic variables of SBRT in 94 patients with multiple primary early-stage lung cancer. Regarding synchronous (≤180 d) and metachronous (>180 d) multiple primary early-stage lung cancer, there was no discernible difference between the two groups (P = 0.440). There was no significant difference in the total number of treatments for multiple primary early-stage lung cancer (P = 0.232) and no significant difference in the type of treatment for multiple primary early-stage lung cancer (P = 0.225) among 59 patients with synchronous multiple primary early-stage lung cancer within 5 years of the first-to-last treatment interval. Conclusion: SBRT has a strong and comparable efficacy for multiple primary early-stage lung cancer compared with single primary early-stage lung cancer, making it a viable treatment choice. Based on age and tumor biological behavior of the lesion, future strategies and procedures for local intervention of multiple primary early-stage lung cancer need to be investigated

Identifying Critical Risk Factors in Green Product Certification Using Hybrid Multiple-Criteria Decision-Making

Green product certification (GPC) is an important means of eliminating the asymmetry of information between consumers and manufacturers in the context of sustainable development. This study examined the critical risk factors in GPC and provided relevant suggestions for managers to reduce risk and ensure the correctness of the process. First, 18 risk factors were summarized along four dimensions: the certification institution, the entrusting enterprise, the certification business, and the implementation of the certification. Second, the Delphi method was used to determine the formal research framework, and the decision-making trial and evaluation laboratory (DEMATEL) method was applied to analyze the causal relationships among the risk factors to identify the ones driving risk and those representing the outcomes of GPC. This was used to construct a causality diagram of the risks related to green certification. Finally, the analytic network process (ANP) method was used to calculate the weight of each risk factor, and the weighted prominence of each is calculated to identify the critical factors. The results showed that the working life and experience of the certification institution were the critical driving risk factors in GPC. Corresponding countermeasures were also proposed to mitigate these risk factors

Optimizing Distribution Routes for Chain Supermarket Considering Carbon Emission Cost

The low-carbon economy and sustainable development have become a widespread consensus. Chain supermarkets should pay attention to path optimization in the process of distribution to reduce carbon emissions. This study takes chain supermarkets as the research object, focusing on the optimization of the vehicle routing problem (VRP) in supermarket store distribution. Firstly, based on the concept of cost-effectiveness, we constructed a green and low-carbon distribution route optimization model with the lowest cost. With cost minimization as the objective function, the total distribution cost in the vehicle delivery process includes fixed cost, transportation cost, and carbon emission cost. The carbon emission cost is calculated using the carbon tax mechanism. Secondly, through integrating the Floyd algorithm, the nearest neighbor algorithm, and the insertion algorithm, a fusion heuristic algorithm was proposed for model solving, and an empirical study was conducted using the W chain supermarket in Wuhan as an example. The experimental results show that optimizing distribution routes considering carbon emission cost can effectively reduce carbon emissions. At the same time, it can also reduce the total costs of enterprises and society, thereby achieving greater social benefits at lower costs. The research results provide effective suggestions for chain supermarkets to control carbon emissions during the distribution process