Engineering Aspects Research Articles

Polycaprolactone, polylactic acid, and nanohydroxyapatite scaffolds obtained by electrospinning and 3D printing for tissue engineering

There is a deficit for bone tissue natural grafts that seek to be covered with synthetic substitutes. Scaffolds generated with 3D printing and electrospinning allow adequate mechanical properties maintaining a structure appropriate for cell growth. Here, a scaffold made up of three-dimensional (3D) printed PLA frameworks added with PCL/PLA/nHA nanofibers was manufactured. The framework showed mechanical properties similar to other reported bone substitutes, while the nanofibers showed diameters between 200 and 850 nm. Scaffolds were suitable for cell adhesion and proliferation when evaluated with fibroblasts, showing cell proliferation into the nanofiber network, a fundamental aspect in tissue engineering.

Uncovering the mystery of the vortex dynamics in a micropolar fluid with multiple magnetic field strips: A novel case study

From transportation to energy production, environmental protection, and medical advancements, vortices are known to influence everything. Therefore, a remarkable aspect of engineering and scientific research in these areas is the prediction, control, and optimization of such vortices. Motivated by these potential applications, we numerically study ‘how confined magnetic fields may give rise to new vortices in the micropolar flow inside a square cavity, by employing the Alternating Direction Implicit approach. Unlike most of the previous studies, we do not assume a uniform magnetic field throughout the flow domain, which is more realistic. Instead, we introduce several confined magnetic fields in the form of multiple horizontal and vertical strips. Further, we have applied the theory of micropolar fluids proposed by Eringen to model the micropolar fluid and visualize the flow patterns around the magnetic strips in the flow regime. Using our self-developed MATLAB codes, we examine how various parameters, such as the magnetic field strength, the number and position of the strips, and the micropolar parameter affect the flow and thermal properties of the micropolar fluid. The findings of this study will contribute to a better understanding of the vortex generation and heat transfer enhancement of micropolar fluids in lid-driven cavities under localized magnetic fields. The study reveals that both the Nusselt number (Nu) and skin friction (CfRe) coefficient decrease by 45% and 1% respectively with a magnetic number (Mn) for a fixed Reynolds number (Re). However, increasing the Reynolds number at a fixed magnetic number increases the Nusselt number (909%) and skin friction coefficient (7%). This means that the higher flow velocity translates into increased wall shear stress and heat transfer, which destabilizes the flow and may cause turbulence. This knowledge can be used to develop new and improved micropolar fluid-based technologies for a variety of applications, such as energy production, medical devices, and microfluidics.

Using New Bioinformatics Strategies at the Design Stage of Genome-edited Plants

The identification of risks associated with novel agricultural products of plant origin obtained via genome editing is an important aspect of genetic engineering. An extensive discussion is currently ongoing worldwide to clarify the similarities and differences between the “old” risks of “classic” GM plants and the “new” ones associated with genome editing, the lack of existing methods for identification and assessment of new risks. We propose here the concept of “safe by design” as applied to protection that is a new interesting tool that introduces good known standards of safety into plant bioengineering. This approach states that design options are identified to minimize or prevent risks and off-target of genome editing at the concept stage. The correlation between experimentally determined and in silico predicted off-target gRNA activity is a major challenge in the CRISPR system application. Today the most studies are focused on efficiency of gRNA design, while we pay attention specifically to the bioinformatics search and study of potential promoters, as the potential risk associates with a possible unplanned change in the transcriptional activity of promoters. We conveyed these strategies in the form of a risk assessment framework for regulation of new genetic technologies.

Tensile efficiency and fatigue life of similar and dissimilar carbon steel joints subjected to rotary friction welding

Rotary friction welding (RFW) is a solid-state welding method that can address the melting point limitation of other welding types; however, the welded area remains at risk of failure due to fatigue during operation. Fatigue failure is difficult to detect and predict, making it a critical failure mode in engineering. Although many fatigue life prediction methods are available, they do not consider the impact of RFW parameters (such as pressure, speed, and friction time) on fatigue strength. Owing to their good mechanical properties and commercial viability, carbon steel of grades C35 and C45 is commonly applied to manufacture main parts in the automotive industry. This study centers on employing RFW to join C35 and C45, representing the first-ever instance of using this technique to weld them together. The primary goal of RFW for C35 and C45 is to construct optimum parts that meet specific design requirements and have a long fatigue life. Findings showed C45–C45 joints (77 %) were more tensile-efficient than C35–C35 joints (73 %). Dissimilar C35–C45 joints reached 60 % of C45 base metal and 76 % of C35 base metal in terms of tensile efficiency. RFW welds had lower tensile strength than their base metals. Optimal results came at 35 MPa friction pressure and 8–12 s friction time for both similar and dissimilar RFW joints using the Coffin–Manson method, dissimilar C33–C45 joint fatigue life improved by over 85 %, aligning C35 and C45 engineering aspects. SEM microstructure analysis showed two regions: non-deformed (NDZ) and plastically deformed (PDZ), with broader PDZ indicating better tensile strength. These findings enhance RFW's efficiency, promoting automotive part longevity and safety.

Advanced engineering materials and materials processing technologies in dental implant and prosthetic treatment with clinical cases

The article deals with materials science issues concerning the application areas in dental engineering. The monograph aims to present the results of the Author’s work against the background of general achievements, indicating the engineering aspects of dental implant-prosthetic treatment. They include clinical cases, most often concerning complete edentulism, with a detailed discussion of the methodology of the material, technological, and structural design of dental prosthetic restorations, especially the impact of additive manufacturing conditions and surface engineering technology on the mechanical properties and structure of prosthetic restorations.The monograph covering the engineering and technical activities of implant prosthetic treatment includes the Author's aspects concerning the development of the methodology of computer-aided design of dental prosthetic restorations and surgical guides ensuring their correct installation in the oral cavity of patients, along with virtual modelling of treatment plans, modelling of the load status of individual elements of implant-prosthetic systems, development of the methodology of computer-aided production of elements of the prosthetic restoration system as well as implants and implant-scaffolds with the use of milling technology in CNC centres and additive manufacturing by selective laser sintering, the results of research on the influence of additive manufacturing conditions on the structure and properties of titanium and its alloy Ti6Al4V and cobalt alloy Co25Cr5W5MoSi containing studies of biochemical properties for applications for implant-prosthetic purposes in dentistry, the results of tests on the influence of ALD atomic layer conditions on the structure and surface properties of metals and their alloys used in implant-prosthetic treatment in dentistry and the results of tests of prosthetic fillings used in the treatment of Tooth decay.The basis for all the described achievements of the monograph are the comprehensive results of research related to the study of the structure and properties of engineering materials, especially titanium and cobalt alloys used in dentistry, subjected to additive manufacturing using the Selective Laser Sintering SLS method and surface treatment using the Atomic Layer Deposition ALD method, as a domain of materials engineering, in the context of the Industry Integrated Idea 3xI 4 model. 0/5.0 and the 6xE 6 Expectation Principle, which there is a paradigm for materials science. What is important in the approach are the results of biological tests of materials produced in such a way, leading to numerous applications in the Author’s clinical practice in cooperation with dentists and the development of a general concept of a research, design, and production centre for prosthetic restorations and virtual acquisition of diagnostic data from cooperating dental clinics.The article is a monographic study referring to numerous of the Author’s publications, patents, and presentations at scientific conferences and invention fairs, in which very extensive source information is provided concerning both a very large number of literature items and extensive factual material, including the results of materiallographic studies and descriptions of clinical cases, although this study also presents numerous aspects not yet published in any previous works.The study presents, among others, detailed prosthetic and implant-prosthetic solutions implemented by the Author of the study and successfully used by patients. Although the study is formally qualified in the engineering and technical sciences in materials engineering, it has strong links with biomedical engineering and the applied area of interventional dentistry.Numerous original publications, patent solutions, completed projects, and awards at the International Innovation Fair discussed in the monograph, as well as clinical experience related to the treatment of thousands of dental patients in our Author’s clinic, confirm the originality of the approach and indicate the innovative nature of the achievements presented in the article so far. Many years of experience have led to the launch of a constantly developed production centre for prosthetic restorations and a virtual structure for obtaining diagnostic data from cooperating dental clinics. The article addresses scientists dealing with materials engineering applied in interventional dentistry and dental engineers in practice dealing with this issue.

Transformation of Type I Fuzzy Logic into Interval Type II Fuzzy Logic-based Unit Voltage Template with Controlled Load

The interval type II fuzzy logic controller (IT2FL) is a recent artificial intelligent technology which is applied in many aspects of electrical power engineering and controlling strategies these days. The improving of Distribution Static Synchronous Compensator (DSTATCOM) control algorithms is still ongoing, because the control strategy of DSTATCOM device is considered as a decisive factor which affects the performance of DSTATCOM device in enhancing the quality of power in the distribution grids. The improving process focuses in two main aspects the DC capacitor voltage response to the control system and the mitigation of the harmonics which are produced by the controlled and uncontrolled rectified loads. In this paper, the interval type II fuzzy logic controller (IT2FL) based the Unit Voltage Template strategy (UVT) is examined by the MATLAB program with two different ranges of input signals, and compared with the type I Fuzzy logic controller (T1FL). The IT2FL based UVT shows promising results in improving the deformed shape of source current waves in comparison with the other controllers.

3D biomimetic scaffold’s dimensional accuracy: a crucial geometrical response for bone tissue engineering

Abstract Additive manufacturing has emerged as a trending methodology for producing different simple to complex geometries in minimum lead time, which in turn gives better quality attributes when compared to conventional manufacturing procedures. Fabrication of polylactic acid-based porous scaffold prototypes by 3-dimensional printing has been extensively performed successfully by many researchers. The dimensional accuracy of the 3-dimensional printed part is a very crucial aspect of bone tissue engineering. Dimensional precision of 3-dimensional biomimetic scaffolds has been a response characteristic somehow less focused on by researchers, though it is essential as it acts as a stereotype for defect recuperation while consequently developing extracellular matrix and bone regeneration. The present paper fosters re-tuning the process parameters of a fused deposition modeling based 3-dimensional printer while considering the dimensional precision as a response parameter by the Taguchi optimization technique using a full factorial design L27 orthogonal array set of design of experiments. The crystallinity of the polylactic acid filament material was assessed using differential scanning calorimetry and X-ray diffraction. The thermal breakdown of filament material was investigated utilizing a thermogravimetric analyzer. According to Taguchi’s signal-to-noise ratios, the optimum values were 0.14 mm of layer thickness, 20 mm s−1 of printing speed, and 80 % of infill percentage. In order to justify the results, response surface methodology was employed. R-square values for Taguchi and the response surface models were 88.61 % and 68.71 %, respectively.

To Each According to Their Space-Need: Communes in Outer Space

Space settlement advocates frequently argue that we will soon be able to settle humans in space. Surviving on Mars is clearly a pre-requisite to settlement, and much work has been done examining the engineering aspects of this endeavor. Much less work has been done, however, on questions related to how to arrange a society in space. Early settlements will be dangerous, isolated, and cramped, and picking a social arrangement that is likely to result in a vibrant and productive society will be critical. Moreover, given the high stakes of this endeavor, being able to anticipate and ameliorate likely social problems ahead of time would be beneficial. Some important questions to consider include: How can settlements pick members who are likely to contribute as much as or more than they take from the society? How will they make sure everyone continues to contribute? How will they retain their most talented members? The literature on space settlements frequently posits that early settlements are particularly likely to be communal, though settlement scholars rarely consult the social sciences literature to explore whether or not communes would be a good social model for space. This article explores lessons from three major communal movements—the Hutterites, kibbutzim, and 60s-era communes. Similar social problems (such as adverse selection, free riding, and brain drain) are frequently encountered in these communes, and communards employ similar solutions to ameliorate these problems. This article also discusses how the nature of these social constraints may differ in the space environment, and the potential implications of the observation that religious communes seem to be more likely to persist than purely socialist ones.

Identification of cable tension through physical models and non-contact measurements

Determining the static and dynamic response of structural cables is a mechanical problem of theoretical and practical interest in many aspects of civil engineering. In particular, the cable tension is a fundamental variable to be assigned in direct design problems, as well as a fundamental unknown to be assessed in inverse identification problems. The present paper outlines an original analytical strategy for identifying the axial tension of inclined sagged cables in cable-stayed structures, based on static measurements. Starting from the classic formulation of an inextensible, perfectly flexible model of catenary suspended cables, a perturbation-based low-order polynomial approximation of the static configuration under self-weight is achieved (direct problem). The quadratic and cubic coefficients of the configurational function are tension-dependent quantities, whose analytical expressions can be mathematically inverted to define consistent parametric formulas for tension identification (inverse problem). The experimental assessment of the static cable configuration, which serves as input for the inverse problem, is provided by the geometric data acquired by modern and noninvasive techniques of non-contact measurement. The methodological advantage is that the laser scanner acquisition of point cloud models can efficiently and economically provide precise and redundant three-dimensional geometric descriptions of the cable configuration, which is suitable for a highly accurate and statistically robust data treatment. Lastly, the identification strategy is successfully applied to a real-scale structure, for tension identification in the stays of a cable-stayed footbridge. The results are discussed from a qualitative and quantitative viewpoint, and finally validated through a comparison with the outcomes of a dynamic identification procedure based on high-speed camera acquisitions.

Unexpected structural complexity of d-block metallosupramolecular architectures within the benzimidazole-phenoxo ligand scaffold for crystal engineering aspects

Design of metallosupramolecular materials encompassing more than one kind of supramolecular interaction can become deceptive, but it is necessary to better understand the concept of the controlled formation of supramolecular systems. Herein, we show the structural diversity of the bis-compartmental phenoxo-benzimidazole ligand H3L1 upon self-assembly with variety of d-block metal ions, accounting for factors such as: counterions, pH, solvent and reaction conditions. Solid-state and solution studies show that the parent ligand can accommodate different forms, related to (de)protonation and proton-transfer, resulting in the formation of mono-, bi- or tetrametallic architectures, which was also confirmed with control studies on the new mono-compartmental phenoxo-benzimidazole H2L2 ligand analogue. For the chosen architectures, structural variables such as porous character, magnetic behaviour or luminescence studies were studied to demonstrate how the form of H3L1 ligand affects the final form of the supramolecular architecture and observed properties. Such complex structural variations within the benzimidazole-phenoxo-type ligand have been demonstrated for the first time and this proof-of-concept can be used to integrate these principles in more sophisticated architectures in the future, combining both the benzimidazole and phenoxide subunits. Ultimately, those principles could be utilized for targeted manipulation of properties through molecular tectonics and crystal engineering aspects.

Inaugural Editorial

Writing an editorial note for the first volume of the new journal of Archives of Advanced Engineering Science (AAES) is a great glory and honor for me. The scope of AAES is not limited to a single aspect of engineering and science and covers various subfields in the applied and fundamental engineering sciences. Particularly, articles with interdisciplinary nature are welcomed. A warm welcome to the inaugural issue of AAES, which is a new exciting title and subject for Bon View Press portfolio journals for 2023. AAES is a new beginning for engineering development in the way to advanced engineering science. I am fortunate and honored to be a member of AAES and take the responsibility of Editor-in-Chief. As can be witnessed in journal title, this pioneering journal aims to address and understand Engineering Science. Subject fields include, but are not limited to, Mechanical Engineering, Electrical and Informatics Engineering, Civil Engineering, Chemical Engineering, Material Engineering, Computer Engineering, Environmental Engineering, Renewable Energy and Resources, Technology and Applications, Sustainable Development and Interdisciplinary science. Today, we feel great happiness to publish the first issue of our journal in November 2023. This issue has six articles on different interesting topics in engineering science. I believe that AAES is providing a vigorously open-access, peer-reviewed, leading platform aiming at publishing the most valuable and Influential research works in the main basic areas of engineering science around the world. To enhance the standard of the journal through publishing high quality papers, we followed the main practices of Committee on Publication Ethics (COPE) and accordingly handled research and publication misconduct. Strict ethical guidelines for editors, authors, and peer reviewers were clearly presented. We introduced desk reject, double-blind peer-review by at least two anonymous reviewers and plagiarism detection to guarantee high standards of AAES.

PARTn: A plugin implementation of the Activation Relaxation Technique nouveau that takes over the FIRE minimisation algorithm

Nowadays, the interoperability and interfacing of codes and libraries have become crucial aspects of software development and engineering, and the basis for enabling and simplifying the sharing of methods and tools, both within and among communities. One of the most important bottlenecks that arises when developing and maintaining an interface of a library with an already existing software, is to keep it aligned with the development route of the latter. This might include significant changes, such as changes in the data structures used by the library, which are communicated through the interface.In this paper, an approach for inserting a new algorithm into existing software is presented, through a minimally invasive interface, that takes over an already present algorithm, and thus changes its original purpose. The approach is applied to the well-established Activation-Relaxation Technique nouveau (ARTn) algorithm, that is revisited and re-engineered to bias and take over the FIRE minimization algorithm, as presently implemented in two community codes for atomistic simulations, namely Quantum ESPRESSO (PWscf) and LAMMPS. ARTn is a well established single-ended saddle-point search algorithm that allows for the exploration of potential energy surfaces. The resulting algorithm acts as a plugin, and is distributed in the form of an external library (pARTn). Program summaryProgram Title: plugin Activation Relaxation Technique nouveau (pARTn)CPC Library link to program files:https://doi.org/10.17632/xpwr56d2yk.1Developer's repository link:https://gitlab.com/mammasmias/artn-pluginLicensing provisions: Apache-2.0/GPLv3Programming language: Modern Fortran and C++Nature of problem: Original ARTn implementation was difficult to interface, port and maintain.Solution method: Full refactoring and re-engineering into a library, which utilizes and biases a minimization algorithm already implemented in the engine, to make it behave as ARTn. The biasing is done by reverse-engineering specific external conditions that drive the displacement of atoms.

Design of Amine-Containing Nanoporous Materials for Postcombustion CO2 Capture from Engineering Perspectives.

ConspectusCarbon dioxide (CO2) capture and storage (CCS) is a means to enable the continued use of fossil fuels in the short term. In particular, postcombustion CO2 capture has attracted considerable attention because it can be retrofitted into existing power plants and industrial plants. Among various CO2 capture technologies, the absorption of CO2 using aqueous amines has been industrially employed for decades. However, such amine scrubbing technologies have inherent limitations of environmental and health concerns due to volatile amine loss, corrosion, and high energy demands for regeneration. To overcome these limitations, CO2 adsorption using solid adsorbents has emerged as a promising alternative due to its noncorrosiveness and low energy demand. Various amine-containing adsorbents have been synthesized and investigated for postcombustion CO2 capture. These materials are prepared by physically impregnating low-vapor-pressure amine polymers or by chemically grafting amines onto nanoporous materials. A wide variety of amine guests and nanoporous hosts (e.g., SiO2, Al2O3, zeolites, MOFs, and polymers) have been combined to develop advanced CO2 adsorbents.The design of CO2 adsorbents is a multifaceted puzzle that must ultimately consider integration with large-scale CO2 capture processes. Various engineering aspects need to be carefully considered. Unfortunately, a significant proportion of previous studies has primarily focused on the use of novel materials for improving the CO2 adsorption capacity. In this Account, we describe key challenges and solutions to develop energy-efficient and stable amine-containing adsorbents for postcombustion CO2 capture via temperature swing adsorption (TSA). We found that a high CO2 working capacity, often overemphasized in the literature, does not necessarily guarantee a low energy demand for CO2 capture. Suppressing coadsorption of H2O during the CO2 adsorption in humid flue gas is also a significant factor. Amine-containing adsorbents can be degraded through various pathways, including hydrothermal degradation of nanoporous hosts and chemical degradation of amine guests via urea formation and oxidation. To inhibit such degradation pathways, it is extremely important to properly design the nanoporous structures of the hosts and the molecular structures of the amine guests. By combining macroporous silica hosts, poly(ethylenimine) (PEI) functionalized with various alkyl epoxides, and phosphate-based oxidative stabilizers, we could synthesize adsorbents exhibiting low energy demands for CO2 capture and unprecedentedly high thermochemical stability under TSA conditions. The macroporous silica host synthesized by assembling fumed silica particles via spray-drying exhibited high hydrothermal stability and enabled uniform distribution of bulky amine polymers within its pores. The functionalization of PEI with alkyl epoxides converted its primary amines into hindered secondary amines, leading to a significant reduction in energy demand for TSA cycles and a remarkable improvement in long-term stabilities. The oxidative stability of amines could be drastically improved by adding phosphate metal-binding reagents, which can poison ppm-level metal impurities that catalyze amine oxidation. The present discussions will provide important insights into designing practical adsorbents for CO2 capture from engineering perspectives.

Democratizing Artificial Intelligence Imaging Analysis With Automated Machine Learning: Tutorial.

Deep learning-based clinical imaging analysis underlies diagnostic artificial intelligence (AI) models, which can match or even exceed the performance of clinical experts, having the potential to revolutionize clinical practice. A wide variety of automated machine learning (autoML) platforms lower the technical barrier to entry to deep learning, extending AI capabilities to clinicians with limited technical expertise, and even autonomous foundation models such as multimodal large language models. Here, we provide a technical overview of autoML with descriptions of how autoML may be applied in education, research, and clinical practice. Each stage of the process of conducting an autoML project is outlined, with an emphasis on ethical and technical best practices. Specifically, data acquisition, data partitioning, model training, model validation, analysis, and model deployment are considered. The strengths and limitations of available code-free, code-minimal, and code-intensive autoML platforms are considered. AutoML has great potential to democratize AI in medicine, improving AI literacy by enabling "hands-on" education. AutoML may serve as a useful adjunct in research by facilitating rapid testing and benchmarking before significant computational resources are committed. AutoML may also be applied in clinical contexts, provided regulatory requirements are met. The abstraction by autoML of arduous aspects of AI engineering promotes prioritization of data set curation, supporting the transition from conventional model-driven approaches to data-centric development. To fulfill its potential, clinicians must be educated on how to apply these technologies ethically, rigorously, and effectively; this tutorial represents a comprehensive summary of relevant considerations.

Optimization of Polyvinyl Alcohol-Based Electrospun Fibers with Bioactive or Electroconductive Phases for Tissue-Engineered Scaffolds

The accurate mimicking of the fibrillary structure of the extracellular matrix represents one of the critical aspects of tissue engineering, playing a significant role in cell behavior and functions during the regenerative process. This work proposed the design of PVA-based multi-component membranes as a valuable and highly versatile strategy to support in vitro regeneration of different tissues. PVA can be successfully processed through electrospinning processes, allowing for the integration of other organic/inorganic materials suitable to confer additive bio-functional properties to the fibers to improve their biological response. It was demonstrated that adding polyethylene oxide (PEO) improves fiber processability; moreover, SEM analyses confirmed that blending PVA with PEO or gelatin enables the reduction of fiber size from 1.527 ± 0.66 μm to 0.880 ± 0.30 μm and 0.938 ± 0.245 μm, respectively, also minimizing defect formation. Furthermore, in vitro tests confirmed that gelatin integration allows the formation of bioactive nanofibers with improved biological response in terms of L929 adhesion and proliferation. Lastly, the processability of PVA fibers with conductive phases such as polyvinylpyrrolidone (PVP) or poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has also been verified. From this perspective, they could be promisingly used to design electroactive composite fibers able to support the regeneration process of electrically stimulated tissues such as nerves or muscles.

A Review of Top-Submerged Lance (TSL) Processing—Part I: Plant and Reactor Engineering

Part I of this series of papers focuses on plant and reactor engineering aspects of the TSL reactor technology. A general flowsheet is presented, while emphasis is given to the definition of different reactor zones in terms of fluid dynamics and occurring reactions. Then, the technical advantages of TSL processing, such as feed flexibility and high conversion rates (due to induced turbulence), low dust generation, and low fugitive emissions, are explained. In addition, the reactor is analyzed part by part, also taking into account patent literature, focusing on furnace design, settling furnaces for molten phase disengagement, feeding systems regarding input material streams such as concentrates and fuels, vessel cooling arrangements, off-gas system, and aspects associated with the refractory lining. Furthermore, specific focus is given to the centerpiece of the TSL reactor, i.e., the reactor lance. Associated developments have focused on establishing a slag coating to hinder lance wear, i.e., the development of cooling mechanisms (e.g., use of fluid-cooled lance and shroud arrangements), the increment of O2 enrichment within the incoming air stream, and influencing of fluid dynamics (e.g., O2 conversion at the lance tip, bubble formation, and bath splashing). Finally, comprehensive tables concerning process developments and commissioned TSL plants are provided thus concluding Part I of the review.

The Influence of Construction Methods on the Stability of Tunnels and Ground Structures in the Construction of Urban Intersection Tunnels

The construction of intersection tunnels in urban induces multiple stress redistribution in the surrounding rock, leading to engineering disasters such as instability in rock strata during excavation, disturbance of supporting structures in existing tunnels, and subsidence of ground adjacent buildings. Employing an appropriate construction method is crucial in circumventing excessive stress concentrations and large-scale rock strata subsidence, making it a key aspect of urban intersection tunnel engineering. In this paper, a numerical model for an urban intersection tunnel is developed based on an underground circular road project in a central business district. We conduct numerical simulations of the excavation processes using the full-section method, step method, and center cross diagram (CRD) method, respectively. The findings indicate that while different construction methods do not change the variation trends of surrounding rock stress and displacement, adjacent ground building deformation, and existing tunnel convergence, they affect the variation degrees. The maximum compressive and tensile stresses in the surrounding rock caused by the CRD method are the smallest, which are 3.56 MPa and 0.76 MPa, respectively. The maximum arch subsidence affected the amount, and horizontal convergence affected the amount of branch tunnel #1 caused by the CRD method are the smallest too, which respectively are 1.428 mm and 0.931 mm. The foundation subsidence and overall inclination of the ground building resulting from the three methods are identical. Then, we discuss the construction safety of the three methods and obtain the influence order on construction stability, which is as follows: full-section method > step method > CRD method. It is concluded that the CRD method is the most suitable for urban intersection tunnel engineering in terms of safety. This study could offer valuable insights for selecting construction methods in urban intersection tunnel engineering and provide a foundation for evaluating the safety and stability of tunnel construction.

Energy, exergy, emission, exergoeconomic, enviroeconomic, and sustainability analysis of diesel engine, fueled by waste cooking oil and waste polyethylene co-pyrolysis oil-diesel blends

This study aims to evaluate the energy, exergy, emission, exergoeconomic, enviroeconomic, and sustainability aspects of a diesel engine utilizing blends of Diesel and co-pyrolysis oil. In this study, oil derived from co-pyrolysis of waste cooking oil and waste polyethylene was blended with Diesel up to 30% proportion. These blends exhibited similar physiochemical properties as regular diesel fuel. Among the blends, D90P10 (90% diesel and 10% co-pyrolysis oil by vol%) showed exceptional performance in terms of sustainability, with a sustainability index value of 1.43. Furthermore, the D90P10 blend achieved the highest energy efficiency at 33.6% and exergy efficiency at 30.3% compared to regular diesel fuel. However, it was noted that D90P10 also exhibited a maximum increase of 25.6% in NOX emissions at fuel injection timing of 25° bTDC. Overall, all the blends displayed improved efficiencies, higher sustainability index values, and lower relative costs compared to using neat diesel fuel with a penalty of higher cost of CO2. Among the tested blends, the D70P30 blend had the minimum cost of CO2, making it a promising and viable alternative to blend. In conclusion, the research suggests that the D70P30 (70% diesel and 30% co-pyrolysis oil by vol%) blend offers a compelling option to be utilized as a blended fuel with diesel, considering its favorable efficiency, sustainability, and cost factors.

A bibliography study of Shewanella oneidensis biofilm.

This study employs a bibliography study method to evaluate 472 papers focused on Shewanella oneidensis biofilms. Biofilms, which are formed when microorganisms adhere to surfaces or interfaces, play a crucial role in various natural, engineered, and medical settings. Within biofilms, microorganisms are enclosed in extracellular polymeric substances (EPS), creating a stable working environment. This characteristic enhances the practicality of biofilm-based systems in natural bioreactors, as they are less susceptible to temperature and pH fluctuations compared to enzyme-based bioprocesses. Shewanella oneidensis, a nonpathogenic bacterium with the ability to transfer electrons, serves as an example of a species isolated from its environment that exhibits extensive biofilm applications. These applications, such as heavy metal removal, offer potential benefits for environmental engineering and human health. This paper presents a comprehensive examination and review of the biology and engineering aspects of Shewanella biofilms, providing valuable insights into their functionality.

Basic Aspects of Skin Tissue Engineering: Cells, Biomaterials, Scaffold Fabrication Techniques, and Signaling Factors

Basic Aspects of Skin Tissue Engineering: Cells, Biomaterials, Scaffold Fabrication Techniques, and Signaling Factors