Imran Mohammad, Mohammed Sarosh Khan, Mohammad Rizwan Ansari
et al.
Background: Microbial adaptation is a fundamental process by which microorganisms dynamically adjust to changes in their environment. Microbial adaptation includes both short-term and long-term mechanisms that enable microorganisms to survive and thrive in changing environmental conditions. Microbial adaptation processes can result in evolutionary changes that provide sustainable advantages. These processes allow microbes to develop traits such as antibiotic resistance and enhanced biofilm formation, ensuring their survival and proliferation in diverse environments. Despite substantial progress, there remains a critical gap in the literature regarding a comprehensive synthesis of microbial adaptation mechanisms and their implications for enhancing food safety and ensuring the sustainable production of industrially valuable biochemicals. Objectives: This document seeks to provide a comprehensive overview of recent advancements in understanding resistance mechanisms to various environmental stresses for enhancement of food safety, including oxidative stress, hyperosmotic stress, thermal stress, acid stress, and organic solvent stress. In addition, the study examines the applications of stress-resistant mechanisms in producing diverse biomolecules and valuable chemicals. Finally, the manuscript offers a discuss prospects for identifying stress-resistant mechanisms through systems biology and further engineering these elements using synthetic biology to enhance productivity. Methods: The literature review sought to cover the most important aspects of stress-resistant mechanisms in the adaptation processes of microorganisms and their role in food safety and sustainable production of valuable biochemicals. This review was not limited to a specific time period, geographic or language scope, or publication type, although preference was given to peer-reviewed open access sources. Results: Researchers have found that adaptive responses of pathogens to factors such as changes in temperature, disinfectants, and storage conditions can pose significant challenges to traditional food safety practices. At the same time, microbial adaptation is an integral part of ecosystem functioning, profoundly influencing processes such as nutrient cycling, decomposition, and soil fertility. The soil microbial community plays a vital role in the safety of cultivated produce, as it acts as a key indicator of soil ecological status and the effectiveness of remediation of contaminated soils. Microorganisms serve as climate change signalling indicators, actively contributing to climate regulation. Higher temperatures, precipitation variations, and higher CO2 concentrations can increase microbial growth rates, potentially increasing the prevalence of pathogens in both plant and animal foods. Natural and synthetic microbial stressors are effective mechanisms for food quality and safety management. Adaptation to chemical stress provides microbial resistance to polluted environments and industrial processes, with implications for bioremediation, public health, and environmental sustainability. Conclusion: Microbial adaptation results from the interplay of environmental stressors, genetic variation, ecological interactions, and anthropogenic impacts that determine the resilience, diversity, and adaptive capacity of microbial communities in a variety of habitats and ecosystems. By manipulating these adaptive pathways through combined or sequential stressors (e.g., low heat and low pH), food technologists can disrupt microbial survival without compromising nutritional value. As the environmental stressor landscape continues to rapidly evolve, driven by anthropogenic activities, climate shifts, and emerging environmental disturbances, monitoring how microorganisms acclimate and evolve in response to these dynamic forces remains important.
Quantum computing has demonstrated the potential to solve computationally intensive problems more efficiently than classical methods. Many software engineering tasks, such as test case selection, static analysis, code clone detection, and defect prediction, involve complex optimization, search, or classification, making them candidates for quantum enhancement. In this paper, we introduce Quantum-Based Software Engineering (QBSE) as a new research direction for applying quantum computing to classical software engineering problems. We outline its scope, clarify its distinction from quantum software engineering (QSE), and identify key problem types that may benefit from quantum optimization, search, and learning techniques. We also summarize existing research efforts that remain fragmented. Finally, we outline a preliminary research agenda that may help guide the future development of QBSE, providing a structured and meaningful direction within software engineering.
The field of software engineering is embedded in both engineering and computer science, and may embody gender biases endemic to both. This paper surveys software engineering's origins and its long-running attention to engineering professionalism, profiling five leaders; it then examines the field's recent attention to gender issues and gender bias. It next quantitatively analyzes women's participation as research authors in the field's leading International Conference of Software Engineering (1976-2010), finding a dozen years with statistically significant gender exclusion. Policy dimensions of research on gender bias in computing are suggested.
Dislocations are line defects in crystalline solids and often exert a significant influence on the mechanical properties of metals. Recently, there has been a growing interest in using dislocations in ceramics to enhance materials performance. However, dislocation engineering has frequently been deemed uncommon in ceramics owing to the brittle nature of ceramics. Contradicting this conventional view, various approaches have been used to introduce dislocations into ceramic materials without crack formation, thereby paving the way for controlled ceramics performance. However, the influence of dislocations on functional properties is equally complicated owing to the intricate structure of ceramic materials. Furthermore, despite numerous experiments and simulations investigating dislocation-controlled properties in ceramics, comprehensive reviews summarizing the effects of dislocations on ceramics are still lacking. This review focuses on some representative dislocation-controlled properties of ceramic materials, including mechanical and some key functional properties, such as transport, ferroelectricity, thermal conductivity, and superconducting properties. A brief integration of dislocations in ceramic is anticipated to offer new insights for the advancement of dislocation engineering across various disciplines.
ABSTRACT Crumb rubber (CR)-modified asphalt shows positive effects on engineering performance and environmental conservation. However, its limited compatibility with asphalt due to unstable interactions poses challenges for its application. The incorporation of polyurethane precursor-based reactive modifier (PRM) facilitates the establishment of a three-dimensional crosslinked network structure within the asphalt, thereby enhancing pavement performance and compatibility. In this study, a novel compound-modified asphalt (CPMA) was prepared with CR and PRM. The performance of CPMA was assessed using the Dynamic Shear Rheometer (DSR), Blend Beam Rheology (BBR) and storage stability tests. Microstructure and modification mechanism were revealed by Atomic Force Microscopy (AFM) and Fluorescence Microscopy (FM) analyses. The results show that CPMA produced using an optimized process has better high-temperature performance and fatigue life than CR-modified asphalt (CRMA) and PRM-modified asphalt (PMA). Polar molecules, such as asphaltenes and resins, are crosslinked by the PRM to form a three-dimensional network, which enhances the thermal storage stability of CPMA. Furthermore, the flexibility and resilience of CR mitigated the low-temperature hardening of PMA. Physicochemical compound modifications provide significant advantages in terms of performance enhancement and system stability and demonstrate the potential of CR and PRM to complement and enhance their respective applications.
Engineering a sustainable world requires to consider various systems that interact with each other. These systems include ecological systems, economical systems, social systems and tech-nical systems. They are loosely coupled, geographically distributed, evolve permanently and generate emergent behavior. As these are characteristics of systems of systems (SoS), we discuss the engi-neering of a sustainable world from a SoS engineering perspective. We studied SoS engineering in context of a research project, which aims at political recommendations and a research roadmap for engineering dynamic SoS. The project included an exhaustive literature review, interviews and work-shops with representatives from industry and academia from different application domains. Based on these results and observations, we will discuss how suitable the current state-of-the-art in SoS engi-neering is in order to engineer sustainability. Sustainability was a major driver for SoS engineering in all domains, but we argue that the current scope of SoS engineering is too limited in order to engineer sustainability. Further, we argue that mastering dynamics in this larger scope is essential to engineer sustainability and that this is accompanied by dynamic adaptation of technological SoS.
Active Learning (AL) is a well-known teaching method in engineering because it allows to foster learning and critical thinking of the students by employing debate, hands-on activities, and experimentation. However, most educational results of this instructional method have been achieved in face-to-face educational settings and less has been said about how to promote AL and experimentation for online engineering education. Then, the main aim of this study was to create an AL methodology to learn electronics, physical computing (PhyC), programming, and basic robotics in engineering through hands-on activities and active experimentation in online environments. N=56 students of two engineering programs (Technology in Electronics and Industrial Engineering) participated in the methodology that was conceived using the guidelines of the Integrated Course Design Model (ICDM) and in some courses combining mobile and online learning with an Android app. The methodology gathered three main components: (1) In-home laboratories performed through low-cost hardware devices, (2) Student-created videos and blogs to evidence the development of skills, and (3) Teacher support and feedback. Data in the courses were collected through surveys, evaluation rubrics, semi-structured interviews, and students grades and were analyzed through a mixed approach. The outcomes indicate a good perception of the PhyC and programming activities by the students and suggest that these influence motivation, self-efficacy, reduction of anxiety, and improvement of academic performance in the courses. The methodology and previous results can be useful for researchers and practitioners interested in developing AL methodologies or strategies in engineering with online, mobile, or blended learning modalities.
For small-scale liquid rockets, pressure-fed systems are commonly favoured due to their simplicity and low weight. In such systems, accurate regulation of both tank and injector pressures over a wide range of upstream pressures is critical $-$ more accurate regulation allows for higher engine efficiency and minimal tank mass, thus improving flight performance. However, existing methods such as dome-loaded pressure regulators are inflexible, or require extensive characterization to function accurately. These methods also suffer from limited orifice size, droop, and slow reaction times, making them unsuitable for throttling by adjusting pressures in flight, which are increasingly important as propulsively landing rockets become more common. To overcome these challenges, we designed an electronic pressure regulator (eReg), a multi-input multi-output system utilising closed loop feedback to accurately control downstream pressures. Our design is simple, low-cost and robust: with a single ball valve actuated by a motor, we regulate both gaseous pressurant and cryogenic liquid propellant at high flow rates (1.14 kg/s of liquid; 0.39 kg/s of gas) and upstream pressures (310 bar). Using 2 eRegs to regulate propellant tank pressures, and 2 eRegs for regulating propellant flow to the engine, we demonstrated our system's ability, in a static fire test, to regulate pressures accurately (within 0.2 bar) while simultaneously throttling our engine. To the best of our knowledge, this is the first time any undergraduate team has successfully throttled a liquid bipropellant engine.
Valvular heart disease refers to any cardiovascular condition that affects one or more of the heart’s four valves: the aortic and mitral valves on the left side of the heart, and the pulmonic and tricuspid valves on the right side. While these conditions primarily develop as a result of aging, they can also be caused by congenital abnormalities, specific diseases, or physiological processes such as rheumatic heart disease and pregnancy. Surgical replacement of the faulty valve with prosthetic valves remains the preferred and most effective treatment for all types of VHD. In 2020, over 180,000 heart valve replacements were performed in the US alone [1]. Charles Hufnagel is considered the pioneer in the design of prosthetic heart valves. The first Hufnagel heart valve was implanted in 1952 using a Lucite tube and methacrylate ball in the descending aorta. Over the past century, significant advancements have been made in the development of prosthetic heart valves, and continuing research is dedicated to engineering optimal designs. [2] (Figure 1). The prosthetic heart valve comprises three components: the valve ring, the valve leaf, and the sewing ring (Figure 2). The valve ring and leaf are typically made of titanium, 316L stainless steel (SS) or cobaltchromium (Co-Cr) alloys, low-temperature isotropic pyrolytic carbon, or expanded polytetrafluoroethylene (ePTFE) or polyethylene terephthalate (PET) [3]. While progressive designs of prosthetic heart valves have improved haemodynamic properties, the introduction of a foreign object into the human body comes with its own set of complications [5]. The common problems include thrombosis, haemorrhage related to anticoagulant use, infections, valve failure, tissue hyperplasia, and overgrowth. Thrombogenicity or clot formation on the surfaces of the internal prosthesis is triggered by the adhesion and activation of platelets on them. This in turn is guided by the protein layer, especially human plasma fibrinogen (HPF). Inflammatory reactions such as restenosis and calcification are also caused by the release of toxic ions from the metals or alloys and the degradation of polymeric components of the artificial valves. A promising strategy to limit thrombogenicity is to modulate HPF behaviour at the blood-material interface by altering the physicochemical properties of the valve’s (or any prosthetic device’s) surface. Surface modifications aim to optimize various aspects of blood-material interactions, including protein adsorption, thrombin generation and blood coagulation, platelet adhesion, aggregation and activation, and cellular behaviour at the prosthesis surface [6]. A recent study showed the relationship between surface crystallographic structure and platelet adhesion. Valve rings are often made of titanium or pyrolytic carbon, the surface of which is often engineered to have a layer of titanium oxide [7]. The rutile crystallographic structure typically has three lowindex (110), (100), and (101) facets. HPF has been reported to unfold into a trinodular form on the hydrophobic (110) facet and has a globular conformation in the more hydrophilic (001) facet [8]. Such conformational changes result in altered platelet adhesion in the two phases. As seen in Figure 3, the hydrophilic (001) phase has a higher distribution of platelets, and therefore presents a higher risk of thrombogenicity [9]. Two approaches have been reported for the surface modification of heart valves – the application of surface coatings, and the patterning of the valve surface. Early approaches to surface modification involved applying a bioinert coating that acts as a physical barrier between the valve and the biomedium (blood). Various carbon coatings, including diamond-like carbon, have been utilized to enhance the biocompatibility and hemocompatibility of implants [10]. Studies have shown that hydrogen-free DLC (diamond-like carbon) coatings with a higher bonding ratio of sp/sp2 exhibit improved blood compatibility [11]. The use of ultrananocrystalline diamond (UNCD) coatings avoids graphitization and film delamination in pyrolytic carbon-based mechanical heart valves. UNCD also results in minimum thrombin formation, in comparison to pyrolytic carbon alone, boron-doped UNCD, microcrystalline diamond, and silicon carbide films, represented as Pyc, BD-UNCD, MCD, and SiC, respectively, in Figure 4. Ceramic coatings such as TiO2 and TiN have also been studied because of their biocompatibility and
Aviation applications are facing the challenges of cooling high-power and high-heat-flux electronic equipment. Traditional cooling methods cannot cope with thermal requirements greater than a heat flux of 100 W/cm2. In this study, the ground test bench of a pump-driven two-phase cooling loop (MPCL) system is constructed, and the control strategy of the system is designed. The cooling ability and resistance characteristics of the system are tested, and the mathematical model is developed. The results show that the mechanical pump drives the two-phase cooling system with good thermal performance. The designed copper cold plate is able to effectively handle 6 kW concentrated heat sources with a heat flux of 120 W/cm2. A 10 kW heat source can be effectively cooled by the MPCL system using 70% less working fluid than single-phase cooling under designed working conditions. The surface temperature of the heating element can be stabilized at 63–70 °C, which meets the temperature requirements of the chip. Additionally, the temperature is uniform between the evaporator branches, with a temperature difference below 5 ℃. The pressure drop of the phase-change segment is below 400 kPa, and the resistance characteristics can be described by the Kim and Mudawar models.
Heating and ventilation. Air conditioning, Low temperature engineering. Cryogenic engineering. Refrigeration
We demonstrate that the efficiency of effective negative temperature-based quantum Otto engines, already known to outperform their traditional counterparts operating with positive-temperature thermal reservoirs, can be further improved by terminating the isochoric strokes before the working substance reaches perfect equilibrium with its environment. Our investigation encompasses both Markovian and non-Markovian dynamics during these finite-time isochoric processes while considering a weak coupling between the working substance and the reservoirs. We assess the performance of these engines as they undergo a transition from the Markovian to the non-Markovian regime using two figures of merit: maximum achievable efficiency at a certain finite time during the isochoric heating stroke, and overall performance of the engine over an extended period during the transient phase of this stroke. We show that the maximum efficiency increases with the increase of non-Markovianity. However, the overall engine performance decreases as non-Markovianity increases. Additionally, we discover the existence of effective negative temperature-based necessarily transient quantum Otto engines. These engines operate within an extended operational domain, reaching into temperature ranges where conventional effective negative temperature-based quantum Otto engines, which rely on perfect thermalization during the isochoric strokes, are unable to function. Furthermore, this extended operational domain of an effective negative temperature-based necessarily transient quantum Otto engine increases as non-Markovianity becomes more pronounced.
Recent helium shortages and helium price increases have lead to an increased emphasis being placed on conserving helium. The need to conserve helium must be balanced with need to maintain the high levels of purity necessary to prevent operational problems caused by contamination. Helium losses and contamination control are especially important for test stands that have cryogenic distribution systems operating continuously with frequent changeover of cryogenic temperature components that are being tested. This paper describes a mathematical model to estimate the quantity of helium lost and the purity of the helium after the pump and backfill procedure is complete. The process to determine the optimal time during pump down to cut off pumping and start backfilling is described. There is a tradeoff between trying to achieve the lowest possible pressure during pumping and the quantity of air leaking into the volume while pumping is occurring. An additional benefit of careful selection of pump and backfill parameters in conjunction with real-time pressure monitoring can reduce the labor and time required to complete a successful pump and backfill procedure. This paper is intended to be a tool for engineers to review their pump and backfill procedures and measured data to optimize helium losses, system purity, and labor required.
Accumulated heat input during layer deposition causes high residual stress in the Wire-Arc Additive Manufacturing (WAAM) components. The developed residual stress results in defects like distortion, delamination, cracks, and low fatigue life. To deal with such engineering problems, numerical methods have always been required. It gives an insight into the system that can be used for real-world applications. Consequently, a sequentially-coupled finite element model has been developed to simulate the thermal-structural behaviour of the feedstock during and after deposition in the WAAM process. Precisely, a novel multi-level layer-wise heat input approach characterized by four different stages is compared with the layer-wise single heat input strategy. The variation of thermal and residual stress distributions has been studied based on the different cases proposed related to layer-wise multi-level heat loading. A good agreement between predicted and experimentally observed temperature and residual stress values has been observed. The developed framework predicted thermal distribution with an average error of 9.71%, 9.13%, 7.57%, and 4.52% for case #1, case #2, case #3, and case #4, respectively. In addition to that, longitudinal stresses in the modelled component recorded a reduction of 17.94% for four-level heat input (case #4) compared to the respective value observed in case #1. Therefore, a multi-level heat input strategy is recommended over a single-level heat input approach for the components with small deposition length manufactured through the WAAM process.
Abstract Eutectic high entropy alloys exhibit both high strength and remarkable plasticity. To explore their potential engineering applications, AlCoCrFeNi2.1 eutectic high entropy alloy was diffusion bonded, and the element diffusion behavior, interfacial microstructure evolution and mechanical properties of the resultant joints were studied. With the increase of bonding temperature, the voids gradually decreased and the dominant mechanism of voids disappearance transformed from interfacial diffusion to viscoplastic deformation. While increasing the bonding temperature to 1050 °C, the interface disappeared and a continuous solid solution structure formed at the original interface, which was beneficial for improving the joint strength. Meanwhile, the voids still existed at the interface near the B2 phase due to the synergistic effect of low diffusion rate of elements and inferior plasticity in B2 phase. The shear strength of the joints increased and the fracture mode gradually transformed from brittle fracture to ductile fracture with increasing the temperature. The highest shear strength joint of 648 MPa could be obtained at 1050 °C, which was equal to that of base metal, and the uncoordinated deformation between FCC phase and B2 phase resulted in the appearance of cleavage planes and dimples on the fracture surface at 1000 °C.
Abstract Increasingly rigorous temperature detection applied to characterize physico-chemical state has stimulated thriving demands for contactless optical thermometry, which must overcome obstacles of complex preparation, low sensitivity, poor stability and inflexible design. Herein, a new optical thermal-sensitive LaTiSbO6:Mn4+ and its upgraded engineering frameworks are firstly constructed and systematically analyzed. The title phosphor exhibits specific single-band narrow emission (FWHM = ~31 nm) in deep-red region centered at 683 nm and superior thermal-sensitivity (SR = 2.75% K−1, 298–418 K) based on reliable fluorescence lifetime mode. Outstanding robustness of the phosphor concluded from aging experiment highlights the prerequisites of its practical duration and functional independence in diversified architecture. Through phosphor-in-glass (PiG) strategy, robust products are controllably organized without ascertainable interfacial reaction between introduced particles and glass matrix, yielding intriguing improved performance (SR = 3.01% K−1) inherited from LaTiSbO6:Mn4+. Moreover, fabricated heterogeneous PiG architecture, spatially confining LaTiSbO6:Mn4+ and YAG:Ce3+ to block unfavorable energy-transfer depletion, facilely accomplish dual-mode thermometry without significant mutual interference, integrating the Mn4+-lifetime and highly recyclable fluorescence intensity ratio (FIR) from the Ce–Mn non-thermally-coupled system. This work not only suggests LaTiSbO6:Mn4+ as a promising candidate, but also expands new horizons with the topological composite pathway toward rational designing and perfecting multi-mode thermometer or other versatile constructions.