Engineering Development Research Articles

Exploring the first-stage ignition and model optimization in the comprehensive study of n-dodecane oxidation

n-Dodecane is commonly employed as a surrogate for investigating the combustion characteristics of jet and diesel fuels. Enhancing comprehension of its combustion behavior and developing accurate chemical kinetics models for simulating combustion is of paramount importance in engine development. This study focuses on a detailed exploration of n-dodecane oxidation kinetics under low-temperature conditions and presents a novel dataset concerning the first-stage ignition delay time. A broad spectrum of experimental conditions is investigated, encompassing a range of temperature (600 ∼ 1350 K), pressure (5 ∼ 20 atm), equivalence ratios (0.5 ∼ 1.0), and dilution gases (N2 and Ar). Additionally, combustion experiments in a pure oxygen environment are performed, contributing valuable data to existing research. To enhance the precision of the chemical reaction kinetics model of n-dodecane, this study integrates updated rate coefficients obtained from the latest theoretical calculations for specific reaction classes. The improved rate rule provides a more accurate reference for the construction of the chemical reaction kinetics model of long straight alkane. The resulting improved model excels in accurately predicting both the first-stage ignition delay time and the total ignition delay time under a wide range of operational conditions. Additionally, the model performance is rigorously evaluated through a comprehensive assessment against a diverse array of datasets gathered from various literature references. The results show that, in contrast to the previously proposed model, this enhanced model provides highly reliable predictions over a broad range of parameters.

Experimental investigation on thermal performance of phase change materials–metal foam composites in ocean thermal engine

Because battery-powered underwater vehicles have limited long-term mission capacity, the development of ocean thermal engines that can harvest ocean thermal energy (OTE) is a potential solution to this “energy limitation” issue. Ocean thermal engines using solid-liquid phase change materials (PCM) for thermal–mechanical energy conversion. This study examined the effects of combining PCMs with metal foams (MF) on OTE harvesting. Two phase change materials and three MFs were considered. Experiments were conducted to measure the temperature change inside the PCM, phase change duration, and volume change to evaluate the thermal and energy-harvesting performances under different temperature and pressure conditions. Results show that(1) Mixed PCM composed of 95 % n-hexadecane and 5 % n-octane melting point decreased by 0.9–1.6 °C and volume change rate reduced by 16–40 % compared to pure n-hexadecane. (2) The mixed PCM has by 14–18 % higher output power than pure n-hexadecane. (3) Within the test range, to maximize the power density, the optimal porosity of copper foam and back pressure during melting were 94 % and 20 MPa, respectively. This study provides useful insights into the design and optimization of ocean thermal engines.

Teaching old dogs new tricks: genetic engineering methanogens.

Methanogenic archaea, which are integral to global carbon and nitrogen cycling, currently face challenges in genetic manipulation due to unique physiology and limited genetic tools. This review provides a survey of current and past developments in the genetic engineering of methanogens, including selection and counterselection markers, reporter systems, shuttle vectors, mutagenesis methods, markerless genetic exchange, and gene expression control. This review discusses genetic tools and emphasizes challenges tied to tool scarcity for specific methanogenic species. Mutagenesis techniques for methanogens, including physicochemical, transposon-mediated, liposome-mediated mutagenesis, and natural transformation, are outlined, along with achievements and challenges. Markerless genetic exchange strategies, such as homologous recombination and CRISPR/Cas-mediated genome editing, are also detailed. Finally, the review concludes by examining the control of gene expression in methanogens. The information presented underscores the urgent need for refined genetic tools in archaeal research. Despite historical challenges, recent advancements, notably CRISPR-based systems, hold promise for overcoming obstacles, with implications for global health, agriculture, climate change, and environmental engineering. This comprehensive review aims to bridge existing gaps in the literature, guiding future research in the expanding field of archaeal genetic engineering.

Science, Technology, Engineering and Mathematics (STEM) Professional Development: An Evaluation of Teachers’ Learning on Project-based Learning (PBL) Approach in Teaching

Science, Technology, Engineering and Mathematics (STEM) Professional Development: An Evaluation of Teachers’ Learning on Project-based Learning (PBL) Approach in Teaching

Development and verification of an electron Monte Carlo engine for applications in intraoperative radiation therapy.

In preparation of future clinical trials employing the Mobetron electron linear accelerator to deliver FLASH Intraoperative Radiation Therapy (IORT), the development of a Monte Carlo (MC)-based framework for dose calculation was required. To extend and validate the in-house developed fast MC dose engine MonteRay (MR) for future clinical applications in IORT. MR is a CPU MC dose calculation engine written in C++ that is capable of simulating therapeutic proton, helium, and carbon ion beams. In this work, development steps are taken to include electrons and photons in MR are presented. To assess MRs accuracy, MR generated simulation results were compared against FLUKA predictions in water, in presence of heterogeneities as well as in an anthropomorphic phantom. Additionally, dosimetric data has been acquired to evaluate MRs accuracy in predicting dose-distributions generated by the Mobetron accelerator. Runtimes of MR were evaluated against those of the general-purpose MC code FLUKA on standard benchmark problems. MR generated dose distributions for electron beams incident on a water phantom match corresponding FLUKA calculated distributions within 2.3% with range values matching within 0.01mm. In terms of dosimetric validation, differences between MR calculated and measured dose values were below 3% for almost all investigated positions within the water phantom. Gamma passing rate (1%/1mm) for the scenarios with inhomogeneities and gamma passing rate (3%/2mm) with the anthropomorphic phantom, were>99.8% and 99.4%, respectively. The average dose differences between MR (FLUKA) and the measurements was 1.26% (1.09%). Deviations between MR and FLUKA were well within 1.5% for all investigated depths and 0.6% on average. In terms of runtime, MR achieved a speedup against reference FLUKA simulations of about 13 for 10 MeV electrons. Validations against general purpose MC code FLUKA predictions and experimental dosimetric data have proven the validity of the physical models implemented in MR for IORT applications. Extending the work presented here, MR will be interfaced with external biophysical models to allow accurate FLASH biological dose predictions in IORT.

Importance of Biopolymers in Pharmaceutical and Medical Fields

Biopolymers have gained significant traction in the pharmaceutical and medical fields due to their unique properties and versatile applications. These naturally derived polymers exhibit remarkable characteristics such as biodegradability, biocompatibility, renewability, affordability, and availability. Their role in tissue engineering, wound healing, and biosensor development has been extensively explored. In tissue engineering, biopolymers serve as scaffolds or matrices, supporting cell growth, proliferation, and differentiation for both hard and soft tissue regeneration. Hard tissue scaffolds often incorporate biopolymers like collagen, chitosan, and gelatin, combined with bioactive ceramics like hydroxyapatite, mimicking the natural composition of bone. Soft tissue scaffolds employ biopolymers such as collagen, gelatin, elastin, and alginate, fabricated into hydrogels, fibrous meshes, or porous structures for applications like skin, vascular, cardiac, and nerve tissue regeneration. Biopolymers have demonstrated promising potential in promoting wound healing and tissue repair, creating moist wound dressings, absorbing exudates, and providing a favorable environment for tissue regeneration. Biopolymers like collagen, chitosan, and alginate have been investigated for this purpose. In biosensor development, biopolymers offer biocompatibility and the ability to immobilize biomolecules such as enzymes, antibodies, or nucleic acids, serving as matrices for biological recognition elements while maintaining their activity and stability

Blade tip clearance measurement technology in gas turbines

Many technologies are used for engine development and testing but no technology has been successfully adopted for long term monitoring over the life of the engine. The challenge is to find a technology that is suitable for long term, high temperature operation but that can also provide accurate and reliable measurement. Blade turbine monitoring is an important area of work for improvements in gas turbine operation. Blade tip clearance measurements offer improvement in engine efficiency by enabling active clearance control. However, this is a difficult measurement because of the harsh turbine environment. The high temperature microwave sensor presented in this paper is one of the most promising candidates for clearance measurement. It has been tested on the high pressure stage of a 25MW gas turbine engine during different operating modes

Creating a computer model of a synchronous motor for the implementation of the project «Creation of a series of electric motors with a modernized rotor for electric transport of low power»

RELEVANCE. The challenges of creating modern permanent magnet synchronous motors require solving technical problems in conjunction with economic realities. Due to the use of permanent magnets in the construction of synchronous motors, their cost limits their industrial application. Therefore, there is an urgent issue of optimizing the design of synchronous motors, which can be solved by changing the topology.TARGET. The goal is to create more economical permanent magnet synchronous motors (PMSMs) in low-power electric vehicles. It is planned to implement a new method for constructing PMSM. This solution will reduce weight and size parameters and increase specific power, which are important indicators for electric transport.METHODS. To modernize modern synchronous motors, a complex topological optimization method based on a genetic algorithm is proposed.RESULTS. A computer model was obtained in the form of calculation of electromagnetic fields in the stator and rotor of a synchronous motor with permanent magnets.CONCLUSION. Modeling the parameters of synchronous motors with permanent magnets has a low degree of development in the domestic mechanical engineering due to the lack of developed infrastructure in the field of low-power electric transport; the creation of domestic developments in this area is of a strategic nature.

Biofunctionalisation strategies of material surface and the inspired biological effects for bone repair

AbstractDue to trauma and disease, bone defects endanger the healthy life of human beings. At present, the gold standard for bone defect repair is still autologous bone transplantation and allogeneic bone transplantation. However, its insufficient source, potential disease transmission and immune rejection limit its clinical application. Therefore, the development of bone repair materials plays an important role in promoting bone repair. As the interface between material and tissue, the surface of the material plays an important role in the reaction after implantation, which determines the effectiveness of defect repair treatment. With the development of surface engineering and technology, bone repair materials have developed from biological inertia to biological activity by endowing various biological functions by controlling the composition, topological morphology and structure of the material surface etc. The inspired biofunctionalisation of material surface includes the capacities of inducing osteogenesis, promoting angiogenesis, antibacterial, immune regulation etc., as well as integration of postoperative repair and treatment. The authors review the biofunctionalisation of biomaterial surface and the inspired biological effects for bone repair, mainly including physical and chemical properties of material surface to regulate osteogenesis, and functional strategy of bone repair material surface.

Teaching design and implementation of traffic system simulation course based on a computer virtual reality software under the background of engineering education

AbstractThe further reform and development of engineering education courses can help improve the teaching quality of higher education institutions, implement the fundamental task of talent cultivation, and provide important support and channels for cultivating high‐quality and supportive engineering technical talents. The traffic system simulation course is an applied science closely related to engineering technology. It mainly cultivates senior engineering technical talents engaged in research and development of transportation engineering, analysis of road traffic characteristics, and transportation planning and design. Considering the characteristics of the traffic system simulation course, this study puts forward the course teaching design based on computer virtual reality software. Combined with the training objectives of applied talents in the traffic system simulation course, this study focuses on how to reform the teaching content and teaching mode with the help of Vissim computer simulation software. The course teaching design refines and optimizes the teaching content by the use of computer software. The use of Vissim software in the course enriches the teaching content and methods and stimulates students' interest in learning. Through the guidance of active exploration and self‐directed learning for students, the traffic system simulation course reform has created a more positive and effective learning environment for students, which helps to cultivate their exploratory spirit and innovative ability. The implementation of the course teaching reform has gradually improved students' learning initiative and ability to master course content, as well as their practical problem‐solving abilities. Good teaching results have been achieved.

Code Generator Development to Transform IFML (Interaction Flow Modelling Language) into a React-based User Interface

Model-Driven Software Engineering (MDSE) is a software development approach that uses the Model to be the main actor of the development. MDSE can be applied to User Interface (UI) Development so that a model for the UI can be built, and then a transformation can be made to turn it into a running application. In this research, we develop UI Generator to support UI Development with the MDSE approach. This UI Generator can also support UI Development in Software Product Line Engineering (SPLE) paradigm. The UI is modeled with Interaction Flow Modeling Language (IFML) diagram. Then The IFML diagram is transformed into React-Based UI by the UI Generator. The UI Generator is developed with Acceleo on Eclipse IDE to transform IFML into React Code with the transformation rules defined in this research. The UI generator is also enriched with display settings and static page management to address user customization needs. The experimental results show that the UI Generator can generate a functional website. Besides evaluating the working product, UI Generator is evaluated qualitatively well based on six quality criteria as an SPLE supporting tool.

Study on Spray Characteristics and 0-D Model of Marine Injector with Large Orifice Diameter

ABSTRACT Low carbon, cleanliness and efficiency are the three key challenges facing the development of diesel engines. Biodiesel is a crucial step in the transition from fossil fuels to zero-carbon fuels. This study was carried out to investigate the effects of injection pressure and ambient pressure on the biodiesel spray characteristics of a marine large orifice diameter injector. Injection mass has a nonlinear relationship with short injection duration and a linear relationship with long injection duration. Increasing the injection pressure shortens the nonlinear stage and enhances the linear effect. When the injection pressure is increased from 35 MPa to 140 MPa, the injection delay is shortened by 10% (2.5 ms), and the diameter nozzle has almost unaffected on the injection delay. The Arai model was revised based on experimental data to improve its prediction effect on sprays with large nozzle diameters. The new model considers the effects of fuel density and ambient density on penetration before and after breakup, respectively. The penetration of the new model is still proportional to time of after start of injection (t) before the breakup and proportional to t0.6 after the breakup. Increasing the ambient pressure enhances the influence of injection conditions on dimensionless penetration. Compared with the Arai model, the new model reduces the sensitivity of the dimensionless penetration to the injection pressure. Research on biodiesel spray and spray models under large nozzle diameter conditions will be of great help to the application of low-carbon and clean fuels in marine diesel engines.

Utilization of low-stability variants in protein evolutionary engineering

Evolutionary engineering involves repeated mutations and screening and is widely used to modify protein functions. However, it is important to diversify evolutionary pathways to eliminate the bias and limitations of the variants by using traditionally unselected variants. In this study, we focused on low-stability variants that are commonly excluded from evolutionary processes and tested a method that included an additional restabilization step. The esterase from the thermophilic bacterium Alicyclobacillus acidocaldarius was used as a model protein, and its activity at its optimum temperature of 65 °C was improved by evolutionary experiments using random mutations by error-prone PCR. After restabilization using low-stability variants with low-temperature (37 °C) activity, several re-stabilizing variants were obtained from a large number of variant libraries. Some of the restabilized variants achieved by removing the destabilizing mutations showed higher activity than that of the wild-type protein. This implies that low-stability variants with low-temperature activity can be re-evolved for future use. This method will enable further diversification of evolutionary pathways.

Development of growth selection system and pocket engineering of d-amino acid oxidase to enhance selective deamination activity toward d-phosphinothricin.

D-amino acid oxidase (DAAO)-catalyzed selective oxidative deamination is a very promising process for synthesizing l-amino acids including l-phosphinothricin (l-PPT, a high-efficiency and broad-spectrum herbicide). However, the wild-type DAAO's low activity toward unnatural substrates like d-phosphinothricin (d-PPT) hampers its application. Herein, a DAAO from Caenorhabditis elegans (CeDAAO) was screened and engineered to improve the catalytic potential on d-PPT. First, we designed a novel growth selection system, taking into account the intricate relationship between the growth of Escherichia coli (E. coli) and the catalytic mechanism of DAAO. The developed system was used for high-throughput screening of gene libraries, resulting in the discovery of a variant (M6) with significantly increased catalytic activity against d-PPT. The variant displays different catalytic properties on substrates with varying hydrophobicity and hydrophilicity. Analysis using Alphafold2 modeling and molecular dynamic simulations showed that the reason for the enhanced activity was the substrate-binding pocket with enlarged size and suitable charge distribution. Further QM/MM calculations revealed that the crucial factor for enhancing activity lies in reducing the initial energy barrier of the reductive half reaction. Finally, a comprehensive binding-model index to predict the enhanced activity of DAAO toward d-PPT, and an enzymatic deracemization approach was developed, enabling the efficient synthesis of l-PPT with remarkable efficiency.

Decreased Tiam1-mediated Rac1 activation is responsible for impaired directional persistence of chondrocyte migration in microtia.

The human auricle has a complex structure, and microtia is a congenital malformation characterized by decreased size and loss of elaborate structure in the affected ear with a high incidence. Our previous studies suggest that inadequate cell migration is the primary cytological basis for the pathogenesis of microtia, however, the underlying mechanism is unclear. Here, we further demonstrate that microtia chondrocytes show a decreased directional persistence during cell migration. Directional persistence can define a leading edge associated with oriented movement, and any mistakes would affect cell function and tissue morphology. By the screening of motility-related genes and subsequent confirmations, active Rac1 (Rac1-GTP) is identified to be critical for the impaired directional persistence of microtia chondrocytes migration. Moreover, Rho guanine nucleotide exchange factors (GEFs) and Rho GTPase-activating proteins (GAPs) are detected, and overexpression of Tiam1 significantly upregulates the level of Rac1-GTP and improves directional migration in microtia chondrocytes. Consistently, decreased expression patterns of Tiam1 and active Rac1 are found in microtia mouse models, Bmp5se/J and Prkralear-3J/GrsrJ. Collectively, our results provide new insights into microtia development and therapeutic strategies of tissue engineering for microtia patients.

Applications of Biomolecular Nanostructures for Anti-Angiogenic Theranostics.

Angiogenesis is a physiological process of forming new blood vessels that has pathological importance in seemingly unrelated illnesses like cancer, diabetes, and various inflammatory diseases. Treatment targeting angiogenesis has shown promise for these types of diseases, but current anti-angiogenic agents have critical limitations in delivery and side-effects. This necessitates exploration of alternative approaches like biomolecule-based drugs. Proteins, lipids, and oligonucleotides have recently become popular in biomedicine, specifically as biocompatible components of therapeutic drugs. Their excellent bioavailability and potential bioactive and immunogenic properties make them prime candidates for drug discovery or drug delivery systems. Lipid-based liposomes have become standard vehicles for targeted nanoparticle (NP) delivery, while protein and nucleotide NPs show promise for environment-sensitive delivery as smart NPs. Their therapeutic applications have initially been hampered by short circulation times and difficulty of fabrication but recent developments in nanofabrication and NP engineering have found ways to circumvent these disadvantages, vastly improving the practicality of biomolecular NPs. In this review, we are going to briefly discuss how biomolecule-based NPs have improved anti-angiogenesis-based therapy.

Influence of compression ratio on the performance characteristics of a spark ignition engine

In this study, the influence of the compression ratio on the performance characteristics of a gasoline engine was investigated in detail using COMSOL simulations. Four compression ratios — 8, 9, 10 and 11 — were investigated at different engine speeds between 1000 and 1800. The analysis focused on power output, braking performance and fuel consumption in order to decipher the complicated relationships between compression ratios and engine dynamics. The results showed a significant increase in power output with increasing compression ratio, highlighting the delicate balance required for optimal power generation. Braking power increased with higher compression ratios, indicating a potential improvement in braking performance. In addition, the study showed a correlation between increased fuel consumption and higher compression ratios, highlighting the need for strategic fuel-saving measures. These results contribute to the understanding of gasoline engine behavior and provide insights into the trade-offs that need to be made when adjusting the compression ratio. Recommendations include experimental validation, exploration of dynamic compression control, research into integrated braking systems, investigation of sustainable fuel strategies and a focus on multi-metric optimization. The observed increase in power output at higher compression ratios highlights an important aspect of engine optimization. Engineers and researchers need to carefully consider compression ratio adjustments to ensure optimal power generation while maintaining efficiency. This insight can guide the development of engines that strike an ideal balance between power and fuel efficiency.

ОСНОВНЫЕ ЭТАПЫ РАЗВИТИЯ КАФЕДР, ВЕДУЩИХ ПОДГОТОВКУ ТЕПЛОТЕХНИКОВ И ТЕПЛОЭНЕРГЕТИКОВ В ДОНЕЦКОМ НАЦИОНАЛЬНОМ ТЕХНИЧЕСКОМ УНИВЕРСИТЕТЕ

Donetsk National Technical University, established in 1921, has become the largest center for training highly qualified engineers and scientists. The article presents the stages of development of heat engineering and heat power directions of Donetsk National Technical University at the departments of “Technical Thermophysics” and “Industrial Heat and Power Engineering”. Over the long history of the existence of the two departments, more than five thousand students have been trained. The teams of both departments continue active scientific and pedagogical activities, preserving historical traditions and continuity of scientific schools.

Development of Science, Technology, Engineering, and Mathematics (STEM)-Based Chemistry E-module Learning Materials on the Topic of Reaction Rate

Development of Science, Technology, Engineering, and Mathematics (STEM)-Based Chemistry E-module Learning Materials on the Topic of Reaction Rate

Estimation of the mean effective pressure of a spark ignition internal combustion engine using a neural network, considering the wall-wetting dynamics

The management and development of internal combustion engines stand as critical pursuits within the automotive and related industries. Utilizing cylinder pressure as feedback, engine controllers rely on intricate systems to regulate performance. However, due to the inherent complexity and nonlinearity of engines, direct measurement of cylinder pressure through pressure sensors is costly and computationally demanding. Consequently, the need for accurate and detailed engine models becomes paramount. Neural networks offer a promising avenue for simulating internal combustion engines, combining speed and precision. By treating the engine as an enigmatic entity, neural networks can construct detailed models. This study aims to employ two types of neural networks—multilayer perceptron and radial basis functions—to train and build a model of an internal combustion engine. These networks will simulate and estimate the engine's mean suitable pressure, allowing for a comparison of their effectiveness. Prior to implementing the neural network architecture, an engine model was constructed in MATLAB to gather necessary training data. This preliminary step ensured a robust foundation for subsequent network design and implementation. In summary, this research focuses on leveraging neural networks to model internal combustion engines, utilizing both multilayer perceptron and radial basis functions to simulate engine behavior and estimate mean suitable pressure.