Engineering Concepts Research Articles

Cascaded chiral birefringent media enabled planar lens with programable chromatic aberration

Wavefront control is the fundamental requirement in optical informatics. Planar optics have drawn intensive attention due to the merits of compactness and light weight. However, it remains a challenge to freely manipulate the dispersion, hindering practical applications, especially in imaging. Here, we propose the concept of frequency-synthesized phase engineering to solve this problem. A phasefront-frequency matrix is properly designed to encode different spatial phases to separate frequencies, thus makes arbitrary dispersion tailoring and even frequency-separated functionalization possible. The periodically rotated director endows cholesteric liquid crystal with a spin and frequency selective reflection. Moreover, via presetting the local initial orientation of liquid crystal, geometric phase is encoded to the reflected light. We verify the proposed strategy by cascading the chiral anisotropic optical media of specifically designed helical pitches and initial director orientations. By this means, planar lenses with RGB achromatic, enhanced chromatic aberration and color routing properties are demonstrated. Inch-sized and high-efficient lenses are fabricated with low crosstalk among colors. It releases the freedom of dispersion control of planar optics, and even enables frequency decoupled phase modulations. This work brings new insights to functional planar optics and may upgrade the performance of existing optical apparatuses.

THE IMPORTANCE OF ENGLISH FOR SPECIFIC PURPOSES BASED ON THE ENGINEERING STUDENTS’ PERCEPTIONS

English for Specific Purposes (ESP) is garnering significant attention and anticipation for its contribution to the teaching and learning process at the Polytechnic of Road Transportation Safety in Indonesia. Consequently, this study offers valuable insights into the perceptions of cadets at a vocational college regarding the significance of the ESP course within the transportation engineering program. Specifically, this paper aims to explore the cadets' perspective on the role of ESP in their future careers. By conducting a qualitative descriptive study, four types of questionnaires were administered to a total of ninety second-year cadets who are pursuing a major in transport engineering. The findings reveal that the cadets/students recognize the importance of ESP as a crucial subject that supports their future employment prospects. Moreover, they acknowledge the appropriate allocation of time to ESP within their curriculum, recognizing its necessity for their academic success and eventual career advancement. Understanding the importance of ESP is crucial for cadets aspiring to work in the industry. Cadets must have a strong motivation to learn and familiarize themselves with core engineering concepts in order to establish themselves as competitive engineers on a global scale.

A rabbit osteochondral defect (OCD) model for evaluation of tissue engineered implants on their biosafety and efficacy in osteochondral repair

Osteochondral defect (OCD) is a common but challenging condition in orthopaedics that imposes huge socioeconomic burdens in our aging society. It is imperative to accelerate the R&D of regenerative scaffolds using osteochondral tissue engineering concepts. Yet, all innovative implant-based treatments require animal testing models to verify their feasibility, biosafety, and efficacy before proceeding to human trials. Rabbit models offer a more clinically relevant platform for studying OCD repair than smaller rodents, while being more cost-effective than large animal models. The core-decompression drilling technique to produce full-thickness distal medial femoral condyle defects in rabbits can mimic one of the trauma-relevant OCD models. This model is commonly used to evaluate the implant’s biosafety and efficacy of osteochondral dual-lineage regeneration. In this article, we initially indicate the methodology and describe a minimally-invasive surgical protocol in a step-wise manner to generate a standard and reproducible rabbit OCD for scaffold implantation. Besides, we provide a detailed procedure for sample collection, processing, and evaluation by a series of subsequent standardized biochemical, radiological, biomechanical, and histological assessments. In conclusion, the well-established, easy-handling, reproducible, and reliable rabbit OCD model will play a pivotal role in translational research of osteochondral tissue engineering.

Aspects of Ammonia as Green Fuel for Propulsion Systems of Inland Water Vessels

Ships are a crucial backbone of the transport system for goods and people. However, the currently utilized fossil fuels require a green replacement. Ammonia produced from green hydrogen is an interesting, carbon‐free green fuel, which has been demonstrated to be promising for maritime applications. Its application under the specific boundary conditions of river ships and other inland water vessels still deserves a closer evaluation. In this work, ammonia as a green fuel for propulsion systems of inland water vessels is evaluated regarding several technological aspects. These include onboard decomposition for hydrogen release, combustion of ammonia–hydrogen mixtures in internal combustion engines and the thermal integration of the different components. To achieve favorable combustion properties of the fuel, a certain share of the ammonia has to be decomposed in an ammonia cracker to produce a mixture of hydrogen and ammonia. First single‐cylinder engine tests show that the combined combustion of ammonia and hydrogen allow an efficient and reliable process for the investigated high‐speed engine concept. Efficiency values of nearly 40% at part load already are achieved. With proper system integration, it is possible to reasonably operate small‐ and medium‐sized ships with ammonia as a green fuel.

Design and Fabrication of Automated Counting Machine

Abstract: The design and fabrication of an automatic counting device specifically for wedges are presented in this work. The device effectively counts wedges in a variety of industrial processes by utilizing electronic control systems and precise engineering concepts. The design incorporates a user-friendly interface for smooth operation and sensors for precise detection. In order to assure dependable operation, fabrication entails programming embedded systems and assembling specialized components. For businesses producing wedges, the automated counting machine provides a workable way to improve efficiency and quality assurance.

How pressure affects costs of power conversion machinery in compressed air energy storage; Part I: Compressors and expanders

This study addresses a critical economic aspect in compressed air energy storage that has not been discussed much in existing literature: the impact of operating pressure on machinery capital cots. It aims to answer whether the cost per unit of power for power conversion systems changes with the maximum storage pressure. Considering that higher storage pressures are associated with greater energy density, enhanced energy storage capabilities and improved system efficiency. This paper helps clarify uncertainties in initial cost estimations for power-generation plants. Effects of operating pressure on the components and overall sizes and consequently costs of power conversion machinery are individually investigated in two parts. Part I encompasses the compressor and expanders, and part II comprehensively discusses the effects of the operating pressure on the costs of heat exchangers. The analysis employs a conceptual engineering approach, revealing that higher intake pressure reduces overall compressor/expander size, leading to cost savings. Additionally, increasing the number of compression stages for higher storage pressures enhances exergy storage cost-effectiveness. To establish an advanced adiabatic CAES plant with a storage pressure of 200 bar instead of 50 bar, there is potential for a 6 % reduction in $/kW expenditure.

Peach Fuzz: Conceptual Engineering of Color Categories

This article explores the products of conceptual engineering in contemporary media communication and mass culture. The analysis examines the mechanisms and communicative consequences of intentionally creating color categories. The shade known as peach fuzz, selected by the Pantone Institute as the color of the year 2024, is used as a case study. It is shown that in the case of the color of the year, the transmission of the conceptual idea involves two channels simultaneously (visual and verbal), each in two different forms. The author notes that the visual channel is used to ostensively present the shade with specific chromatic characteristics and to develope a complex visual image on this basis. Special attention is paid to the verbal channel, which is utilized in the form of intentionally constructed color designations and supporting stories (conceptual myths). It is concluded that from the perspective of color communication, verbal and visual texts serve fundamentally different functions. The visual representation shows how the viewer should see the color, while the verbal explanation clarifies why this shade is needed. It is demonstrated that the image embedded in the color name sets the desired connotation, which can transform the perception of the shade by adding necessary meanings to it. The verbal story defines a cognitive “point of view” for introducing a new category into an existing color system. 

Evaluating CO 2 retention risk of geological sequestration sites: Physical, time-scale, and site style considerations

With some exceptions, such as fluid phase, pressure evolution, and reservoir geometry, evaluation of CO 2 retention for geological sequestration sites primarily involves well-established seal and trap concepts and methods developed by the petroleum industry. Inputs to a CO 2  retention evaluation (e.g., bed seal capacity analysis) include CO 2  phase, CO 2  and brine density, reservoir pressure and temperature, rock properties, and stress state. The inputs are used to perform capillary and mechanical seal analyses similar to the petroleum industry, but unlike hydrocarbons, CO 2  retention also occurs within the reservoir pore volume by capillary and solubility trapping, adding additional requirement for analyses using reservoir engineering concepts and methodology. Reservoir geometry types for CO 2  storage include conventional traps (depleted hydrocarbon fields, brine-filled traps) and brine-filled reservoirs that lack a conventional trap geometry (e.g., a monocline). Each geometry style and project phase (injection, near-term post-injection, long-term static) requires different retention considerations, for example the CO 2  plume extent and height. Based on a retention evaluation, retention risk and uncertainty may be articulated using a qualitative risk matrix that facilitates early screening, identification of data needs, possible mitigating strategies, and comparisons across a portfolio of potential sites. Thematic collection: This article is part of the Geoscience workflows for CO 2 storage collection available at: https://www.lyellcollection.org/topic/collections/geoscience-workflows-for-CO2-storage

Linguistic imposters

Abstract There is a widespread phenomenon that we call linguistic imposters. Linguistic imposters are systematic misuses of expressions that misusers mistake with their conventional usages because of misunderstanding their meaning. Our paper aims to provide an initial framework for theorising about linguistic imposters that will lay the foundation for future philosophical research about them. We focus on the misuses of the expressions ‘grooming’ and ‘critical race theory’ as our central examples of linguistic imposters. We show that linguistic imposters present a distinctive phenomenon by comparing them to some adjacent phenomena, namely conceptual engineering, linguistic hijacking and dogwhistles. We also address four objections about the extensional adequacy of our definition of linguistic imposters. Finally, we argue that, as linguistic imposters spread, they make some inferences featuring misused expressions more cognitively accessible and seemingly socially licensed to misusers and discuss four types of harms that linguistic imposters are conducive to through these effects.

Search Engine for Open Geospatial Consortium Web Services Improving Discoverability through Natural Language Processing-Based Processing and Ranking

The improvement of search engines for geospatial data on the World Wide Web has been a subject of research, particularly concerning the challenges in discovering and utilizing geospatial web services. Despite the establishment of standards by the Open Geospatial Consortium (OGC), the implementation of these services varies significantly among providers, leading to issues in dataset discoverability and usability. This paper presents a proof of concept for a search engine tailored to geospatial services in Switzerland. It addresses challenges such as scraping data from various OGC web service providers, enhancing metadata quality through Natural Language Processing, and optimizing search functionality and ranking methods. Semantic augmentation techniques are applied to enhance metadata completeness and quality, which are stored in a high-performance NoSQL database for efficient data retrieval. The results show improvements in dataset discoverability and search relevance, with NLP-extracted information contributing significantly to ranking accuracy. Overall, the GeoHarvester proof of concept demonstrates the feasibility of improving the discoverability and usability of geospatial web services through advanced search engine techniques.

Thermoacoustic Fano-based bistable energy converters: A new concept of thermoacoustic engine

In this work, we propose a highly efficient thermoacoustic energy converter based on the concept of Fano-based bistable systems. The proposed device, in its simplest version consists of a bilayer polymeric cylinder with harder core and softer and thinner shell. The heat source enforced at the core-shell interface induces thermo-mechanical stress fields. The stress field causes the occurrence of wrinkling patterns in the shell and the release of acoustic energy by a snap-through-buckling mechanism. We show that, when the shell is acoustically resonant at a specific frequency, the synergetic interplay of snap-through and Fano-resonances is capable of producing high amplitude and long-lasting pressure oscillations. In other words, under specifics conditions, the synergetic interaction between wrinkling instabilities and Fano resonance is able to extract mechanical energy from the heat source. The efficiency of the system in converting heat-into-work under resonant conditions is at least 6 times higher than that out of resonance. Notably, for a temperature difference of 1 K between the heat source (the hot thermal reservoir beneath the resonant shell) and the surrounding water (the cold thermal reservoir above the resonant shell), the system may reach a conversion efficiency above 70% of the theoretical Carnot efficiency. The so-generated mechanical oscillations can be converted in electrical energy for instance by using sound-to-energy converting systems such as conventional loudspeakers. The characteristics of the heat source have been selected to be representative of low-grade thermal sources (e.g. waste-heat, in particular intermittent sources) abundantly available in natural, and industrial contexts. Importantly, the systems may be adapted to many different geometries spanning from the proposed core-shell cylinders in which the heat source can be either inside the tube (for instance an exhaust gas/liquid outlet) or outside the tube, to plates (like a solar panel system).

Aircraft Engine Remaining Useful Life Prediction using neural networks and real-life engine operational data

Aircraft Engine Remaining Useful Life is a key factor which strongly affects flight operations safety and flight operators business decisions. In the article authors decided to present the concept of engine remaining useful life prediction. Proposed method was created as a result of the analysis of the real turbofan engine operational data collected for a few years which was used as an input data for the deep neural network, in order to train, validate and test machine learning algorithms. Two architectures of deep neural networks were created: multilayered deep convolutional neural networks and a long short-term memory network with regression output. Both neural networks were trained, validated and tested on the same engine data and with a various network training options. Results were compared with the neural network performance metrics and figures presenting network prediction convergence. To present how the real-life engine dataset differs the results from the simulated data, both datasets were validated on the same neural network architectures. The main purpose of this article was to present the idea and method of how the artificial neural networks could be used to predict aircraft remaining useful life indicator on the real-life engine operational data not the simulated one.

Prandtl and Ohnesorge numbers dependent of ultrasonic horn energy in Newtonian liquid under batch and continuous flow

The level of knowledge on the non-thermal contribution of ultrasonic wave’s energy to perform physico-chemical phenomena is one of the bottlenecks for the commercialization purposes. Under constant nominal power of transducer (Pn), the input electrical power (Pin) is less and sensitive to the medium’s physical properties. This study attempts to assess the conversion of acoustic to thermal power experimentally and numerically using COMSOL Multiphysis@ for a 24 kHz horn-type sonicator through a medium without any sono-chemical effect. Single- and homogeneous two-phase Newtonian mixtures of sunflower oil and water (o/w) with a relatively wide range of density (914–998 kg/m3) and viscosity (0.5–63.5 mPa.s) were irradiated in a lab-scale vessel (1 L) under batch and continuous flow configuration. The direct influence of Pn (80–400 W) and o/w ratio (0–1) on temperature rise and subsequent thermo-physical properties of liquid and the indirect influence on Pin and thermal energy conversion (TEC) were investigated employing calorimetric method. A new engineering concept including a power factor correlation was proposed and validated for prediction of Pin as a function of liquid space velocity (ϑ), temperature, Prandtl (Pr) and Ohnesorge (Oh) dimensionless groups. The results showed that under constant temperature and Pn, increasing Pr and Oh increased Pin with a similar trend for both modes of operation. An increase in temperature directly led to a decrease in Pin with a power factor closed to “-1”. The Pin in continuous flow was higher compared to batch configuration at similar temperature, liquid properties, and Pn. This effect was more significant with increasing ϑ. An increase in ϑ at constant Pn led to a decrease in the inlet/outlet temperature difference in continuous flow and an increase in Pin. Increasing Pn resulted in higher TEC for both configurations; however, TEC was relatively lower in continuous flow than batch configuration indicating more efficient sonication in continuous flow.

‘You're changing the subject’: An unfair objection to conceptual engineering?

Abstract Conceptual engineering projects are sometimes criticized for ‘changing the subject’. In this paper, I first discuss three strategies that have been proposed to address the change of subject objection. I notice that these strategies fail in similar ways: they all deploy a ‘loose’ notion of subject matter, while the objector can always reply deploying a ‘strict’ notion. Based on this, I then argue that at least current formulations of the change of subject objection (together with the response strategies just mentioned), create an overall defective dialectic, whereby no progress can be made on either side. After considering how such defective dialectic could be (at least partly) fixed, it is concluded that current formulations of the change of subject objection may be dismissed on dialectical grounds, even though some practical lessons may still be retained from the objection.

Recent Progress in Semitransparent Organic Solar Cells: Photoabsorbent Materials and Design Strategies.

The increasing energy demands of the global community can be met with solar energy. Solution-processed organic solar cells have seen great progress in power conversion efficiencies (PCEs). Semitransparent organic solar cells (ST-OSCs) have made enormous progress in recent years and have been considered one of the most promising solar cell technologies for applications in building-integrated windows, agricultural greenhouses, and wearable energy resources. Therefore, through the synergistic efforts of transparent electrodes, engineering in near-infrared photoabsorbent materials, and device engineering, high-performance ST-OSCs have developed, and PCE and average visible transmittance reach over 10% and 40%, respectively. In this review, we present the recent progress in photoabsorbent material engineering and strategies for enhancing the performance of ST-OSCs to help researchers gain a better understanding of structure-property-performance relationships. To conclude, new design concepts in material engineering and outlook are proposed to facilitate the further development of high-performance ST-OSCs.

Geological characteristics and developmental achievements of the large presalt carbonate gas fields in the Amu Darya Basin

The Amu Darya Basin accounts for one of the most abundant natural gas resources globally, it is the main gas supplier to the Central Asian natural gas pipeline. It also holds potential for the natural gas exploration and development. Within this basin, valuable Jurassic carbonate rocks and gypsum-salt-gas-bearing combinations are developed. These include the presalt transitional Middle and Lower Jurassic coal-bearing source rocks, which provide sufficient gas sources, and the Middle and Upper Jurassic reef-shoal carbonate and gypsum salts, forming an effective reservoir–caprock combination. The unique geological configuration forms optimal accumulation conditions for natural gas in the high-energy sedimentary-facies belt of the carbonate platform which controlled by the coal-bearing gas-generation center and large basement ancient uplift area. Large natural gas fields are mainly distributed in the presalt Jurassic carbonate rocks, driven by high-quality hydrocarbon-generation centers, ancient uplift backgrounds, and ultrathick gypsum-salt rocks. While large gas fields have been discovered in large structural traps at the center of the depressions, exploration potential is still remains in the vast area with a burial depth exceeding 4500 m. These make the basin a key area for further exploration. The Amu Darya Right Bank Block located in the northeast of the basin, which has seen 15 years of rapid and efficient exploration and development by PetroChina, has discovered three gas field groups, each contains 2 billion m3 of gas: the western intraplatform shoal, central gently sloping reef beach, and Eastern thrust structure, fracture-cave-type gas field groups. PetroChina has achieved a production capacity of 14 billion cubic meters. In response to the geological and developmental characteristics of the three gas field groups, tailored development strategies have been formulated. The strategies are based on the integrated concept of geological and developmental engineering. Optimization efforts have been made in well pattern deployment, including highly deviated wells, as well as the design of gas field pressurization engineering. In addition, comprehensive evaluations have been conducted, taking the stable production period, water-avoidance distance, and investment considerations into account. The efforts aim to support the project of transforming the Amu Darya River into a model for the efficient development of the “Belt and Road” energy cooperation project.

Female Pre-Service Elementary Teachers’ Conceptualizations of Engineers and Engineering: A Critical Consciousness Perspective

ABSTRACT The purpose of this study was to address issues of potential gender bias in pre-service elementary teachers’ conceptions of engineers and engineering using Freire’s (2018) Critical Consciousness perspective. By identifying the biasness as causal and structural attributions, the study also aimed to construct a critical pedagogy framework for future pre-service elementary teachers to reflect on and to radically reimagine and transform potential gender bias in their conceptions of engineers and engineering. Drawings of engineers and narratives of drawings from 115 pre-service elementary teachers served as data. The analysis comprised a two-step process: (1) identification of patterns through an inductive analysis of the data; and (2) analysis of patterns from the Critical Consciousness perspective to generate themes. Themes included: (1) depictions of male engineers being afforded privileges of having innate abilities to perform engineering from the standpoint of strong disciplinary backgrounds in mathematics and science while depictions of female engineers being afforded privileges of having innate abilities to perform engineering from the standpoint of computing, designing, and coding. (2) depictions of male engineers’ “work” of engineering being related to tangible outcomes like physical products, and (3) depictions of male engineers as authority figures and having the ability to lead the work of engineering. The critical pedagogical framework constructed is a step toward developing a tool for critically reflecting, and radically imagining, reimagining, and thus transforming inequities inherent in future pre-service elementary teachers’ conceptualizations of engineers and engineering.

역공학 교육프로그램 개발을 통한 고등학교 기술과 공학교육 사례연구

This study develops a reverse engineering education program and analyzes its implications in
 response to the emphasis on engineering in the revised 2022 high school Technology Education
 curriculum. To this end, the study examined the concept and model of reverse engineering as well
 as the technology curriculum. A reverse engineering education program was developed following the
 stages of hands-on activity development. To ensure the program’s completeness, expert validation
 and teacher feedback from case presentations at the A City Teachers' Association were incorporated
 to achieve both quantitative and qualitative improvements.
 Program practicality was assessed through a preliminary class conducted with 15 general high
 school students in City A over a period of four days in January 2024, consisting of 10 sessions.
 The meaning of the class was assessed through students' online portfolio materials, recorded class
 videos, and teacher reflection journals. The study’s results are as follows:
 First, reverse engineering offers students opportunities to learn product design principles,
 understand the functions of each component, discern the relationships between components, and
 identify areas for product improvement by dismantling a completed product. It affords students a
 concrete understanding of previously abstract engineering principles by working with actual products.
 Second, developed as a 10-session program following the stages of preparation, development, and
 improvement, the program was applied to 15 general high school students in City A during a
 four-day preliminary class, and the resulting data informed final modifications and completion of the
 education program. Third, student experiences were analyzed through themes such as understanding
 engineering principles through participation, experiences of failure and challenges, sense of
 accomplishment in product operation, interest in engineering, and career exploration.
 This study provides insights into implementing the engineering education emphasized in the
 revised 2022 technical and vocational curriculum in school settings. The results have implications
 for the technology education field and future curriculum revisions.

A proactive safety approach to delivering safer care in obstetrics and gynaecology

Key content In obstetrics and gynaecology, things often ‘go well’ because clinicians make sensible adaptations in response to situations to ensure safety, often within a highly pressurised environment. The adaptations and performance variables that are made under these complex circumstances are not explicitly understood. Understanding the performance variability of clinicians as well as the environmental context that enables good or successful outcomes may bring awareness of how to build adaptive capacities and capabilities in clinicians when working in unpredictable and unanticipated highly pressurised environments. Learning objectives To be aware of the current research in safety‐II and the concept of resilience engineering in illustrating the nature of adaptations that happen in complex clinical contexts. To understand the concept of capability mindfulness, which can help clinicians to focus on their environment and to be alert and aware of correcting errors before they occur. To be aware of these concepts (behaviour and skills) through the lens of ‘what went well’ in clinicians’ responses to unforeseen and unpredictable situations.

[Periodontal tissue regeneration: current therapeutic strategies and future directions in further research].

Chronic and progressive destruction/damage of the periodontal tissues resulted from periodontitis is the leading cause of tooth loss in adults. Traditional periodontal therapies such as scaling and root planning or flap surgery have demonstrated effective in controlling local inflammation and in suppressing/arresting the disease progress of periodontitis. However, those infection control measures cannot help to regenerate lost periodontal tissues to a statistically or clinically significant degree. Although some successes regarding the reduction of the intrabony defect and maintenance the periodontal homeostasis have been achieved in periodontal regenerative procedures, comprising but not limited to guided tissue regeneration (GTR) or bone grafting technique, the restorative effectiveness of the architecture and function of the lost or injured tissues is far from our clinical expectation. The use of the concept, technique, and method of tissue engineering for periodontal regeneration is a hotspot and animal studies have shown interesting outcomes in terms of functional regeneration of lost/damaged support tissues in the periodontium, including alveolar bone, periodontal ligament, and cementum. However, numerous issues need to be addressed before those regenerative approaches can be responsibly transformed to novel clinical therapies. Recently, paradigm that induce homing of host stem cells to site of the periodontium and encourage its innate capability to repair is a new research field termed endogenous regeneration. Given that endogenous regenerative technique avoids ex-vivo cell culture and transplantation, it should be relatively easier to be used in the treatment of clinical patients. Due to the limited oral microenvironment and harsh periodontal local condition for tissue regeneration, as well as poor understanding of periodontal regenerative biology, there is still a long way on the exploration of new effective, practical, and economical therapies to save and protect natural tooth and on combating highly prevalent periodontal disease.