Cutting fluid plays a cooling-lubrication role in the cutting of metal materials. However, the substantial usage of cutting fluid in traditional flood machining seriously pollutes the environment and threatens the health of workers. Environmental machining technologies, such as dry cutting, minimum quantity lubrication (MQL), and cryogenic cooling technology, have been used as substitute for flood machining. However, the insufficient cooling capacity of MQL with normal-temperature compressed gas and the lack of lubricating performance of cryogenic cooling technology limit their industrial application. The technical bottleneck of mechanical—thermal damage of difficult-to-cut materials in aerospace and other fields can be solved by combining cryogenic medium and MQL. The latest progress of cryogenic minimum quantity lubrication (CMQL) technology is reviewed in this paper, and the key scientific issues in the research achievements of CMQL are clarified. First, the application forms and process characteristics of CMQL devices in turning, milling, and grinding are systematically summarized from traditional settings to innovative design. Second, the cooling-lubrication mechanism of CMQL and its influence mechanism on material hardness, cutting force, tool wear, and workpiece surface quality in cutting are extensively revealed. The effects of CMQL are systematically analyzed based on its mechanism and application form. Results show that the application effect of CMQL is better than that of cryogenic technology or MQL alone. Finally, the prospect, which provides basis and support for engineering application and development of CMQL technology, is introduced considering the limitations of CMQL.
Abstract Metallic materials with outstanding cryogenic mechanical properties are highly demanded for cryogenic engineering applications. Here we developed a novel (NiCoCr)92Al6Ta2 medium-entropy alloy (MEA) towards superior cryogenic mechanical properties via elaborating the chemical composition designing and the thermo-mechanical processing. It appears that the twinned (NiCoCr)92Al6Ta2 MEA shows a strongly temperature-dependent mechanical behavior, i.e., when the testing temperature from 298 down to 77 K, the yield strength, ultimate strength and tensile ductility are increased from ∼600 to ∼800 MPa, from ∼1.0 to ∼1.35 GPa and from ∼52% to ∼90%, respectively. An excellent strength-ductility synergy and extraordinary strain hardening capacity were realized in this alloy, in particular the product of tensile strength and elongation is more superior to their reported counterparts. There is a strongly temperature-dependent deformation mechanism transition from the ordinary planar-slip at 298 K to the cooperative plastic mechanisms at 77 K, including stacking faults (SFs) and deformation twins. The excellent cryogenic mechanical properties of this designed MEA stems from the synergic effects of nanotwins, hierarchical SFs and Lomer-Cottrell locks, as well as their extensive interactions, rarely observed in their siblings deformed at room temperature. Furthermore, the deformation twinning acting as an additional/significant mechanism for plasticity and favoring strain hardening, along with the effect of temperature-dependent dislocation-twin interactions, collaboratively delays the onset of necking for enhanced ductility at 77 K.
Abstract Technologically important mechanical properties of engineering materials often degrade at low temperatures. One class of materials that defy this trend are CrCoNi-based medium- and high-entropy alloys, as they display enhanced strength, ductility, and toughness with decreasing temperature. Here we show, using in situ straining in the transmission electron microscope at 93 K (−180 °C) that their exceptional damage tolerance involves a synergy of deformation mechanisms, including twinning, glide of partials and full dislocations, extensive cross-slip, and multiple slip activated by dislocation and grain-boundary interactions. In particular, massive cross-slip occurs at the early stages of plastic deformation, thereby promoting multiple slip and dislocation interactions. These results indicate that the reduced intensity of thermal activation of defects at low temperatures and the required increase of applied stress for continued plastic flow, together with high lattice resistance, play a pivotal role in promoting the concurrent operation of multiple deformation mechanisms, which collectively enable the outstanding mechanical properties of these alloys.
The rapid advance of Generative AI into software development prompts this empirical investigation of perceptual effects on practice. We study the usage patterns of 147 professional developers, examining perceived correlates of AI tools use, the resulting productivity and quality outcomes, and developer readiness for emerging AI-enhanced development. We describe a virtuous adoption cycle where frequent and broad AI tools use are the strongest correlates of both Perceived Productivity (PP) and quality, with frequency strongest. The study finds no perceptual support for the Quality Paradox and shows that PP is positively correlated with Perceived Code Quality (PQ) improvement. Developers thus report both productivity and quality gains. High current usage, breadth of application, frequent use of AI tools for testing, and ease of use correlate strongly with future intended adoption, though security concerns remain a moderate and statistically significant barrier to adoption. Moreover, AI testing tools' adoption lags that of coding tools, opening a Testing Gap. We identify three developer archetypes (Enthusiasts, Pragmatists, Cautious) that align with an innovation diffusion process wherein the virtuous adoption cycle serves as the individual engine of progression. Our findings reveal that organizational adoption of AI tools follows such a process: Enthusiasts push ahead with tools, creating organizational success that converts Pragmatists. The Cautious are held in organizational stasis: without early adopter examples, they don't enter the virtuous adoption cycle, never accumulate the usage frequency that drives intent, and never attain high efficacy. Policy itself does not predict individuals' intent to increase usage but functions as a marker of maturity, formalizing the successful diffusion of adoption by Enthusiasts while acting as a gateway that the Cautious group has yet to reach.
With the advancement of Agentic AI, researchers are increasingly leveraging autonomous agents to address challenges in software engineering (SE). However, the large language models (LLMs) that underpin these agents often function as black boxes, making it difficult to justify the superiority of Agentic AI approaches over baselines. Furthermore, missing information in the evaluation design description frequently renders the reproduction of results infeasible. To synthesize current evaluation practices for Agentic AI in SE, this study analyzes 18 papers on the topic, published or accepted by ICSE 2026, ICSE 2025, FSE 2025, ASE 2025, and ISSTA 2025. The analysis identifies prevailing approaches and their limitations in evaluating Agentic AI for SE, both in current research and potential future studies. To address these shortcomings, this position paper proposes a set of guidelines and recommendations designed to empower reproducible, explainable, and effective evaluations of Agentic AI in software engineering. In particular, we recommend that Agentic AI researchers make their Thought-Action-Result (TAR) trajectories and LLM interaction data, or summarized versions of these artifacts, publicly accessible. Doing so will enable subsequent studies to more effectively analyze the strengths and weaknesses of different Agentic AI approaches. To demonstrate the feasibility of such comparisons, we present a proof-of-concept case study that illustrates how TAR trajectories can support systematic analysis across approaches.
This study explores the effects of cryogenic treatment on the plasticity of TA15 aerospace titanium alloy under ultralow‐temperature extreme conditions. As a critical engineering material, TA15 titanium alloy finds widespread applications in aerospace and related fields. Given its mechanical properties’ strong dependence on microstructure, this research utilizes laser‐directed energy deposition technology to fabricate TA15 titanium alloy and investigates the use of cryogenic treatment to enhance its microstructure and mechanical performance. Comparative analyses are conducted between as‐built (untreated) samples and those subjected to ultralow temperature treatment. The study evaluates the influence of cryogenic treatment on the alloy's microstructure and mechanical behavior through tensile tests, impact tests, friction‐wear tests, and characterization techniques such as scanning electron microscopy, X‐ray diffraction, and electron backscatter diffraction. Results reveal that cryogenic treatment significantly improves the plasticity of TA15 titanium alloy, increasing fracture engineering strain by ≈17.8% while inducing a minor reduction in ultimate tensile strength and yield strength. This enhancement is attributed to a reduced concentration of β‐stabilizing elements (Mo and V) in the β phase, leading to improved plasticity.
A new type of air source heat pump system combined waterless floor heating and hot water supply was proposed, which is characterized in that the refrigerant is condensed directly in the buried pipe for floor heating, at the same time, the high temperature refrigerant is exchanged in the outer coil water heater to produce domestic hot water. The prototype was processed and tested in three modes: single floor heating, two combined supply and single water heater. The experimental results show that the surface temperature of the floor is maintained between 25 ℃ and 33 ℃, and the air temperature is maintained between 18 ℃ and 22 ℃ whether in the sole floor heating mode, dual supply mode, or single water heater mode. Due to the heat storage effect of the capillary floor, the air temperature in the room remained above 18 ℃ within 113~245 min of stopping heating to the room. When the ambient temperature is -5 ℃, after 572.3 min, the water temperature of the water heater rose to 45 ℃; The minimum system heating capacity and EER can reach to 2.70 kW and 3.55, respectively.
Heating and ventilation. Air conditioning, Low temperature engineering. Cryogenic engineering. Refrigeration
From its first adoption in the late 80s, qualitative research has slowly but steadily made a name for itself in what was, and perhaps still is, the predominantly quantitative software engineering (SE) research landscape. As part of our regular column on empirical software engineering (ACM SIGSOFT SEN-ESE), we reflect on the state of qualitative SE research with a focus group of experts. Among other things, we discuss why qualitative SE research is important, how it evolved over time, common impediments faced while practicing it today, and what the future of qualitative SE research might look like. Joining the conversation are Rashina Hoda (Monash University, Australia), Carolyn Seaman (University of Maryland, United States), and Klaas Stol (University College Cork, Ireland). The content of this paper is a faithful account of our conversation from October 25, 2025, which we moderated and edited for our column.
Applications of Large Language Models (LLMs) are rapidly growing in industry and academia for various software engineering (SE) tasks. As these models become more integral to critical processes, ensuring their reliability and trustworthiness becomes essential. Consequently, the concept of trust in these systems is becoming increasingly critical. Well-calibrated trust is important, as excessive trust can lead to security vulnerabilities, and risks, while insufficient trust can hinder innovation. However, the landscape of trust-related concepts in LLMs in SE is relatively unclear, with concepts such as trust, distrust, and trustworthiness lacking clear conceptualizations in the SE community. To bring clarity to the current research status and identify opportunities for future work, we conducted a comprehensive review of $88$ papers: a systematic literature review of $18$ papers focused on LLMs in SE, complemented by an analysis of 70 papers from broader trust literature. Additionally, we conducted a survey study with 25 domain experts to gain insights into practitioners' understanding of trust and identify gaps between existing literature and developers' perceptions. The result of our analysis serves as a roadmap that covers trust-related concepts in LLMs in SE and highlights areas for future exploration.
The development of cryogenic technology has greatly reduced the cost of large-diameter superconducting magnets and the difficulty of operation, making it possible for industrial fields. Our team has developed a large-diameter (room temperature aperture of more than 400 mm) superconducting magnet with direct-conduction cooling by a single GM refrigerator, combined with the designs of the transmission device, we have developed a superconducting magnetic separation water treatment system that can operate continuously. In order to apply this system to practical engineering projects, it is necessary to optimize its operating parameters to improve the equipment’s treatment capacity and ensure the treatment effect. Through experimentation, we obtained relatively reasonable parameters for water flow rate and chain drive speed, which have been verified in actual engineering projects.
This article presents a preliminary thermodynamic evaluation of a refrigeration system using phase change materials (PCM) for defrosting. The objective of this study is to highlight the potential of heat recovery during the operation of the refrigeration system and its subsequent use in the defrosting process. The system is analyzed energetically, considering both the cooling and defrosting cycles using PCM-RT 35 HC. Input data were experimentally measured on a vapor-compression refrigeration system installed in a freezing chamber located in the university campus. The analysis includes the following refrigerants: R32, R404a, R134a, R290, R600a, R600, R1234yf, and R1234ze.The results indicate that as the defrosting time increases, the refrigerant flow rate required for PCM-based defrosting decreases. Furthermore, it was observed that R600 requires the smallest refrigerant flow rate, while R404a requires the highest to defrost the same mass of ice. The analysis reveals that R32 is the most suitable refrigerant for PCM-based defrosting, followed by wet or dry refrigerants (R404a, R134a, R290) and, finally, isentropic refrigerants (R600, R600a, R1234yf, R1234ze). Additionally, it is noted that as the condensing temperature increases, the recoverable heat increases for R32, R404a, R134a, and R290, but decreases for isentropic refrigerants such as R600a, R600, R1234yf, and R1234ze. This analysis was conducted using a computational model implemented in the Engineering Equation Solver software.
Abstract A novel heat treatment route consisting of a low-temperature solution followed by an over-aging treatment at 500 °C is proposed to develop a high-strength, high-cryogenic-toughness maraging steel by forming an ultrafine-grained martensite (α′) and austenite (γ) dual-phase microstructure. Compared to the same maraging steel subjected to the conventional heat treatment with a mostly martensitic microstructure, the present dual-phase microstructure offers a remarkable increase by 12 times of cryogenic impact energy (~140 J at 77 K), while the yield strength is not reduced obviously. A large amount of ultrafine-grained austenite (about 50% volume fraction) are formed in the present steel due to the reversed transformation of martensite to austenite during the over-aging process at 500 °C. It is surprised that the present steel with such a high fraction of austenite still possesses a high yield strength comparable to the conventional maraging steel with a mostly martensitic microstructure. Intensive nanoprecipitates are found not only in martensite but also in austenite phases, indicating both phases have high strength. This is confirmed by nanoindentation test, showing similar hardness values in both martensite and austenite phases. Such intensive nanoprecipitates in both phases ensure the high yield strength of the present steel. The excellent cryogenic toughness of the present steel mainly origins from: (i) the pronounced amount of reversed austenite that are intrinsically tough due to their face-centered cubic (fcc) structure; (ii) transformation-induced plasticity (TRIP) toughening as some austenite grains transforming to martensite during impact test; (iii) the ultrafine-grained structure of both martensite and austenite phases. The present heat treatment route offers a potential solution for processing large engineering components for cryogenic application that require a long heat treatment duration to achieving uniform mechanical properties in the components.
In this research, five groups of steel fiber reinforced cementitious composite (SFRCC) with different fiber volume content (0%, 0.5%, 1.0% 1.5%, and 2.0%) were designed to perform four-point flexural tests on beam specimens to study the effects of polar temperature (20, 0, −25, −50, −75, and −100°C) and fiber volume content on the flexural properties. The flexural toughness index and load holding capacity index were calculated based on the load–displacement curve, and the enhancement and toughening mechanisms of SFRCC by low temperature and steel fibers were analyzed in conjunction with experimental observations. The results of the proposed flexural toughness evaluation method show that the flexural toughness of SFRCC can significantly improve than that of ambient temperature when the temperature is lower than 0°C. With the decrease in temperature, the flexural property of SFRCC increases first and then decreases, and the temperature point of this transition is around −50–−75°C. The flexural property enhancement effect of 1.0% fiber volume content SFRCC is more significant in low temperatures according to the flexural toughness index and load holding capacity index. The conclusion can provide a reference for the application of SFRCC in cryogenic engineering, as well as a simple and quantifier evaluation method for flexural toughness is proposed.
Ebube Alor, Ahmad Abdellatif, SayedHassan Khatoonabadi
et al.
Software engineering (SE) chatbots are increasingly gaining attention for their role in enhancing development processes. At the core of chatbots are Natural Language Understanding platforms (NLUs), which enable them to comprehend user queries but require labeled data for training. However, acquiring such labeled data for SE chatbots is challenging due to the scarcity of high-quality datasets, as training requires specialized vocabulary and phrases not found in typical language datasets. Consequently, developers often resort to manually annotating user queries -- a time-consuming and resource-intensive process. Previous approaches require human intervention to generate rules, called labeling functions (LFs), that categorize queries based on specific patterns. To address this issue, we propose an approach to automatically generate LFs by extracting patterns from labeled user queries. We evaluate our approach on four SE datasets and measure performance improvement from training NLUs on queries labeled by the generated LFs. The generated LFs effectively label data with AUC scores up to 85.3% and NLU performance improvements up to 27.2%. Furthermore, our results show that the number of LFs affects labeling performance. We believe that our approach can save time and resources in labeling users' queries, allowing practitioners to focus on core chatbot functionalities rather than manually labeling queries.
The paper aims to investigate how to improve the performance of a refrigeration system (Rs) that equips a cold room, by incorporating phase change materials (Phase Change Materials - PCMs) in these systems, a study that has not yet been extended experimentally. The study is carried out on a cold room within the National University of Science and Technology Politehnica Bucharest - Faculty of Mechanical and Mechatronics Engineering, Department of Thermodynamics, Engines, Thermal and Refrigeration Equipment. This room is equipped with a refrigeration system with mechanical vapour compression (VCRs), which uses R404A as refrigerant. Mechanical vapour compression refrigeration system (VCRs) with an evaporation temperature below 0 oC causes ice to form on the evaporator leading to reduced performance. Currently, the widely used methods for defrosting are the standard methods, the most used being the electric one, which of course consumes energy. This paper aims to evaluate the availability of heat that could be used in the defrosting process by means of PCMs. The study was made using the Engineering Equation Solver software, several types of PCMs and also different refrigerants (R600a, R600, R1234yf, R1234ze, R152a, R290, R32) and in this way it was intended to identify the right agent to be used for a particular type of PCM. Faculty of Mechanical and Mechatronics Engineering, Department of Thermodynamics, Engines, Thermal and Refrigeration Equipment
Liu Chengning, Liang Xingyu, Shao Liangliang
et al.
Reasonable optimization of the operation strategy is essential for saving energy in the long-term operation of heat pump systems. However, the strategy optimization process is susceptible to load uncertainty, which causes the optimized strategy to save less energy than expected. To address this issue, a method of operation strategy optimization using stochastic load prediction was developed in this study. The method adopts multiple stochastic process samplings to simulate the uncertainty of the load prediction, thereby improving the robustness and energy savings of the operation strategy. The energy-saving properties of the optimization method were verified and analyzed using an air-source heat pump hot-water system. The results show that the novel optimization strategy can reduce the chance of using peak electricity and increase the utilization of off-peak electricity. In the long-term operation simulation, the novel optimization strategy was found to save 6.4% of energy costs compared with the traditional optimization method.
Heating and ventilation. Air conditioning, Low temperature engineering. Cryogenic engineering. Refrigeration
In the context of the "3060 carbon peaking and carbon neutrality goals", promoting energy-efficient transportation and rational utilization is one of the important paths to achieve carbon neutrality, where heat exchangers are known to play a crucial role. Compared with traditional heat exchangers, microchannel heat exchangers significantly reduce the volume while maintaining the same heat exchange capacity. They also significantly improve the heat exchange efficiency and have applications in many important fields. For example, supercritical CO2 (S-CO2) power generation systems, transcritical heat pumps, and refrigeration systems have important application prospects as they are environmentally friendly and offer high-efficiency advantages in the context of the "dual carbon target." Drastic changes in the properties of S-CO2 and the high-temperature and high-pressure requirements of the system pose significant challenges to heat exchanger design, high-temperature and high-pressure resistance, compactness, and efficiency. Therefore, S-CO2 heat exchangers have become a hot topic in scientific and industrial research. In recent decades, significant progress has been made in related research. This paper comprehensively reviews the research progress of microchannel heat exchangers in S-CO2 systems. The paper focuses on different structural forms and design optimization methods of printed circuit heat exchangers (PCHE) and discusses the impact of PCHE optimization on the performance improvement of the entire S-CO2 system. This review provides a comprehensive discussion of S-CO2 microchannel heat exchangers and provides an important reference for the selection, design, and optimization of heat exchangers in systems using CO2 or other supercritical working fluids as the working media for power generation, heat pumps, and refrigeration.
Heating and ventilation. Air conditioning, Low temperature engineering. Cryogenic engineering. Refrigeration
Elizabeth Bjarnason, Mirko Morandini, Markus Borg
et al.
The RET (Requirements Engineering and Testing) workshop series provides a meeting point for researchers and practitioners from the two separate fields of Requirements Engineering (RE) and Testing. The goal is to improve the connection and alignment of these two areas through an exchange of ideas, challenges, practices, experiences and results. The long term aim is to build a community and a body of knowledge within the intersection of RE and Testing, i.e. RET. The 2nd workshop was held in co-location with ICSE 2015 in Florence, Italy. The workshop continued in the same interactive vein as the 1st one and included a keynote, paper presentations with ample time for discussions, and a group exercise. For true impact and relevance this cross-cutting area requires contribution from both RE and Testing, and from both researchers and practitioners. A range of papers were presented from short experience papers to full research papers that cover connections between the two fields. One of the main outputs of the 2nd workshop was a categorization of the presented workshop papers according to an initial definition of the area of RET which identifies the aspects RE, Testing and coordination effect.