446494 research outputs found
Sort by
Enhancing mechanical properties of FSW joints in 6061 aluminum alloy through post-weld shot peening treatment
No full textThis study investigated the effects of post-weld shot peening treatment on friction stir welded (FSW) joints in 6061 aluminum alloy. It is well known that FSW joints experience softening and a reduction in mechanical properties compared to the base material. Shot peening was applied to the weld metal surface to improve its mechanical performance. The FSW process was performed on 3 mm thick 6061 aluminum alloy plates in a butt joint configuration, using a travel speed of 18 mm/min and a spindle rotation of 910 rpm. Three types of shot peening media were used: steel shot (S230), and aluminum oxide (Al24 and Al54). Microstructural analysis revealed that shot peening produced plastic deformation up to a depth of approximately 700 μm from the surface. Tensile tests showed that shot peening with Al54 particles achieved the highest tensile strength of 208 MPa, while impact tests demonstrated the best impact toughness of 0.57 J/mm2 with S230 particles. Vickers hardness testing revealed an increase in hardness in the weld metal area, especially with the S230 steel shot, which outperformed the Al24 and Al54 media. These findings suggest that shot peening, particularly with steel shot, effectively enhances the surface hardness and overall mechanical properties of FSW joints
Evaluation of elevated hearing thresholds produced by models for the simulation of cochlear hearing loss
No full textIntroduction: As the statistical distribution of hearing thresholds moves towards stronger hearing impairments with age, plausible simulations of its perceptual effects are useful for a variety of applications. Four software tools for the simulation of hearing loss, capable of generating audible output, were evaluated. An overview of the simulators is presented, their capabilities and significant signal processing steps are introduced.
Methods: The perceptual evaluation focuses on the simulation of elevated hearing thresholds. Two listening experiments were conducted to assess how accurately the hearing loss simulators can reproduce target audiograms, i.e., elevated hearing thresholds when normal-hearing listeners are subjected to the simulation. Mild and moderate degrees of simulated hearing loss conditions were defined based on typical hearing thresholds of 70- and 80-year-olds. The complementary technical analysis addresses additional simulated consequences of cochlear hearing loss by investigating input-vs.-output level functions and spectral smearing effects.
Results: Statistically significant differences between simulators were found: Good agreement with the target hearing thresholds was found for the simulator “WHIS” (deviations 0 to 6 dB), while the others showed deviations of varying degree (−29 to 7 dB). The created input-output functions proved to be suitable for demonstrating expansive dynamic range processing and explaining the listening experiment results
Dynamic Thermal Adaptive Façades: A Comparative Review of Existing Taxonomies
No full textThe development of adaptive façades with dynamic thermal behaviour represents a promising pathway to enhance building energy performance, particularly in Mediterranean climates. However, the scientific literature reveals a wide array of technologies and approaches, often categorized using inconsistent or overlapping criteria. This paper aims to critically analyse and compare existing classification systems for thermal adaptive façade technologies — specifically those involving movable or switchable insulation components. Drawing on an extensive literature review, including conceptual studies, numerical simulations, and commercial product analyses, the study identifies core classification parameters such as operational nature (passive, hybrid, active), thermal regulation mechanism (airflow control vs. insulation variability), and response scale (macro, micro, nano). It highlights ambiguities in the use of expressions like “dynamic insulation”, often applied inconsistently across different contexts. The paper proposes a refined taxonomy to improve clarity and enable comparative analysis, facilitating more structured scientific communication and future development of modular adaptive façades. The findings aim to support researchers, designers, and policymakers in selecting and optimizing façade technologies adapted to evolving climate challenges and performance standards in sustainable building design
Development and verification of a new natural ventilation system for offices utilizing low-temperature outdoor
No full textIn recent years, due to seasonal changes in Japan, summers and winters have become longer and springs and autumns shorter. As a result, opportunities to utilize natural ventilation, one of the energy-saving methods for air conditioning, have decreased. In order to extend the available period of natural ventilation, the authors developed a natural ventilation system that can utilize low-temperature outdoor air. CFD analyses were performed by simulating one span in an office space of a standard floor where giving internal heat generation and natural ventilation inflow were given. By comparing three inflow patterns, i.e., the peri- counter method that supplies air from the foot of the window, wall slit method that supplies air from the top of the window, and ceiling perforated panel duct method, it was shows that the perforated panel duct method was the most comfortable of which ADPI was over 90%. The aperture ratio of perforated metal panels was also studied to supply low-temperature outdoor air evenly from the ceiling in an office with a depth of approximately 20 meters. Specifically, the flow network calculations were performed to find the difference between the indoor pressure and the duct pressure that finally determined the aperture ratio distribution between 3.0 to 12%. To confirm its effectiveness, full-scale measurements for both cases of calculated aperture ratio and a uniform aperture ratio were conducted. In addition, based on the on-site measurement, it was also confirmed that natural ventilation was promoted by exhausting waste heat from the cogeneration system through voids for buoyancy-induced ventilation, and natural ventilation rate increased. Finally, the actual operation was also analyzed and it was confirmed that by introducing low-temperature outdoor air, the effective time of natural ventilation system increased by 55 to 75%, and the amount of heat removed by natural ventilation increased by 104 to 170%
Building environmental control demand characterization based on multi-occupant coupled temporal and spatial occupancy
No full textEnergy conservation is pivotal for decarbonizing buildings, where occupant-centric part-time- local-space control optimizes thermal supply to match temporal-spatial demand, reducing energy use without compromising comfort. Implementing this strategy requires understanding fine-grained occupancy patterns. While prior studies have examined occupancy characteristics, they predominantly focus on room- scale occupancy or individual behaviors, overlooking localized co-occupancy patterns of multi-occupants that shape collective environmental control demands. This gap hinders personalized, efficient solutions for heterogeneous demand. To address this, we developed a methodology to analyze coupled temporal-spatial occupancy characteristics at localized scales. It identifies prolonged-occupancy subzones within rooms and quantifies temporal (shared occupancy periods) and spatial overlaps (shared occupancy subzones) across individuals. Taking a residential household as example, the analysis contrasts single-occupant profiles with multi-occupant scenarios, revealing synchronous occupancy patterns critical for adaptive control. The findings advance the understanding of collective behaviors, enabling adaptive environmental control strategies and intelligent multi-scenario technologies that harmonize energy efficiency with occupant- centric flexibility. By addressing the interdependence of occupants in shared spaces, this work bridges a critical gap in building operations, offering a pathway to reconcile energy-saving objectives with real-world multi-occupant complexities. The proposed approach supports demand-responsive thermal management, balancing system-level efficiency with individualized comfort in dynamic environments
Differences between sound sources in effects of combined thermal-acoustic environment on comfort
No full textThe combined thermal - acoustic environmental effects and the boundaries of these effects on comfort were of significant importance in the development of subjective perception prediction models. Previous studies on this topic mainly focused on either only one sound source or overall data, and the differences related to sound sources were not fully considered. This study aimed to compare and analyse the differences between positive sounds (music) and negative sounds (fan noise) in the combined effects of thermal - acoustic environment in a laboratory setting. The results showed that the boundaries varied among different sound sources. The boundaries of thermal comfort for music were a little stricter than those for fan noise
Study on the influence of shower water temperature and flow rate on human physiology and psychology
No full textThe purpose of this study is to reveal the dynamic physiological regulation and thermal perception response of the human body during the shower under cold conditions. Eight subjects participated in the shower experiment with different water temperatures (36, 40, 44 ℃) and different flow rates (4, 7, 10 L/min). Three types of data were collected, including environmental parameters, physiological parameters and psychological questionnaires. The results showed that the increase of water temperature can significantly increase the skin temperature (1.02~4.57 ℃) compared with the increase of flow rate (2.32~3.27 ℃). The increase of core body temperature was delayed, and it continued to rise after exposure to cold air after shower. The higher the water temperature and the greater the water flow, the more sweating after the shower (20.644~66.515 g/m2*h). The increase of thermal sensation caused by water temperature and water flow mainly occurs at the moment of contact with water. There was no significant increase in thermal sensation during the shower period. However, the thermal sensation decreased instantaneously after the shower (-2.000~-2.625). The most comfortable water temperature during the shower was 40 ℃, and the flow rate was 7 L/min
Biomedical Applications of Spinel Ferrite Synthesized Via Green Route: A Comprehensive Review
No full textFunctional oxide nanomaterials, especially spinel ferrites (MFe2O4; M = Cu, Co, Mn, Mg, Ni, Zn), have emerged as promising candidates in contemporary biomedicine due to their distinctive magnetic, catalytic, and electrical properties. These materials demonstrate significant potential in various biomedical applications, including targeted drug delivery, antimicrobial therapy, magnetic resonance imaging (MRI), magnetic hyperthermia, wound healing, and antidiabetic treatments. Recent breakthroughs highlight the environmentally sustainable synthesis of ferrite nanoparticles with eco-friendly reducing and stabilizing agents sourced from plant and fruit extracts. This sustainable method reduces hazardous byproducts and energy consumption while improving surface biocompatibility and therapeutic safety. Systematic characterization using techniques such as XRD, FTIR, SEM, TEM, and VSM has enabled precise control of particle size, crystallinity, and cation distribution, which are essential for enhancing biological performance. Notwithstanding considerable advancements, obstacles, including cytotoxicity, biodistribution, and repeatability, persist in hindering clinical translation. Future research should concentrate on long-term safety evaluations, surface functionalization techniques, and in vivo validation to connect green nanotechnology with real therapeutic applications
Integrating nanotechnology with deep learning for engineering, healthcare, and environmental solutions: A review
No full textCombining nanotechnology and deep learning methods is a leading-edge frontier in engineering solutions, with unparalleled prospects for innovation and growth. The synergistic combination blends the scale and precision of nano-materials with the predictive capability and resilience of artificial intelligence. Deep learning methods can process enormous amounts of data collected by nano-scale sensors, designing and optimizing materials at the atomic level. This integration makes possible the creation of self-healing smart nano-materials, highly efficient energy storage devices, and ultra-sensitive healthcare diagnostic tools. Additionally, deep learning methods can expedite the discovery of new nanostructures and their uses with much less time and expense compared to conventional experimental approaches. As this multidisciplinary area continues to grow, it holds the potential to transform numerous industries, such as electronics, healthcare, environmental science, and energy technology, towards more efficient, sustainable, and smart engineering solutions
Silent Threat: Insecticide Resistance and Escalating Dengue Cases in India
No full textThe increasing incidence of dengue in India coincides with growing insecticide resistance in Aedes mosquito populations, undermining the efficacy of conventional vector control strategies. The introduction of DDT in the 1940s revolutionized mosquito control, forming the backbone of the global malaria eradication efforts, but widespread resistance and environmental concerns led to its reduced use. Subsequent adoption of organophosphates and carbamates provided effective alternatives by inhibiting acetylcholinesterase, though resistance again emerged across vector populations. The development of pyrethroids in the 1980s enabled low-dose, cost-effective vector control interventions like insecticide-treated nets and indoor residual spraying, significantly reducing the burden of vector borne diseases. However, rapid expansion of resistance at global scale compromised their long-term effectiveness. In response to these limitations, WHO promoted integrated vector management and facilitated the deployment of newer classes of insecticides such as neonicotinoids, microbial larvicides, and insect growth regulators to combat resistance and ensure sustainable control. This review provides a comprehensive analysis of the evolution of insecticide resistance. Specifically, it elucidates the mode of action of major classes of insecticide, the resistance mechanisms, and context-dependent deployment strategies crucial for preserving the effectiveness of vector control interventions against dengue, malaria, Zika, and other vector-borne diseases