219 research outputs found

    Electrohydrodynamic Atomization for Minimum Quantity Lubrication (EHDA-MQL) in End Milling Ti6Al4V Titanium Alloy

    Get PDF
    Titanium alloy Ti6Al4V is a difficult-to-machine material which is extensively used in the aerospace and medical industries. Machining titanium is associated with a short tool life and low productivity. In this paper, a new cooling-lubrication system based on electrohydrodynamic atomization was designed, manufactured and tested and the relevant theory was developed. The major novelty of the system lies within the use of electrohydrodynamic atomization (EHDA) and a three-electrode setup for generating lubricant droplets. The system was tested and compared with that of flood, minimum quantity lubrication (MQL) and compressed air machining. The proposed system can extend the tool life by 6 and 22 times when compared with MQL and flood cooling, respectively. This is equivalent to more than 170 min tool life at 120 m/min cutting speed allowing for significant productivity gains in machining Ti6Al4V

    Prominent autistic traits and subthreshold bipolar/mixed features of depression in severe anorexia nervosa

    Get PDF
    Autistic traits are associated with a burdensome clinical presentation of anorexia nervosa (AN), as is AN with concurrent depression. The aim of the present study was to explore the intertwined association between complex psychopathology combining autistic traits, subthreshold bipolarity, and mixed depression among people with AN

    State-of-the-art cooling and lubrication for machining Inconel 718

    Get PDF
    Inconel 718 is the most used nickel superalloys with applications in aerospace, oil&gas, nuclear and chemical industries. It is mostly used for safety-critical components where the condition of the surface is a significant concern. The combination of mechanical, thermal and chemical properties of Inconel 718, has made it a difficult-to-machine material. Despite recent advances in machining Inconel 718, achieving desired surface integrity with prescribed properties is still not possible. Different machining environments have been investigated for improving the machinability of Inconel 718 and enhance the surface integrity of machined components. This paper provides a new investigation and classification into recent advances in the machining of Inconel 718 regarding surface integrity, mostly concentrated on turning applications. The major findings and conclusions provide a critique of the state-of-the-art in machining environments for Inconel 718 together with future directions for research. Surface integrity has been evaluated in terms of surface topology as well as mechanical and microstructural properties. The impact of various cooling and lubrication methods has been investigated. It has been found that surface integrity is affected by the thermomechanical conditions at the cutting zone which are influenced by the cutting parameters, cutting tool, tool wear and cooling/lubrication condition. The current technologies are incapable of delivering both productivity and sustainability whilst meeting surface integrity requirements for machining Inconel 718. High-pressure cooling has shown the potential to enhance tool wear at the expense of higher power consumption

    State-of-the-art cooling and lubrication for machining Inconel 718

    Get PDF
    Inconel 718 is the most used nickel superalloys with applications in aerospace, oil&gas, nuclear and chemical industries. It is mostly used for safety-critical components where the condition of the surface is a significant concern. The combination of mechanical, thermal and chemical properties of Inconel 718, has made it a difficult-to-machine material. Despite recent advances in machining Inconel 718, achieving desired surface integrity with prescribed properties is still not possible. Different machining environments have been investigated for improving the machinability of Inconel 718 and enhance the surface integrity of machined components. This paper provides a new investigation and classification into recent advances in the machining of Inconel 718 regarding surface integrity, mostly concentrated on turning applications. The major findings and conclusions provide a critique of the state-of-the-art in machining environments for Inconel 718 together with future directions for research. Surface integrity has been evaluated in terms of surface topology as well as mechanical and microstructural properties. The impact of various cooling and lubrication methods has been investigated. It has been found that surface integrity is affected by the thermomechanical conditions at the cutting zone which are influenced by the cutting parameters, cutting tool, tool wear and cooling/lubrication condition. The current technologies are incapable of delivering both productivity and sustainability whilst meeting surface integrity requirements for machining Inconel 718. High-pressure cooling has shown the potential to enhance tool wear at the expense of higher power consumption

    Future research directions in the machining of Inconel 718

    Get PDF
    Inconel 718 is the most popular nickel-based superalloy, extensively used in aerospace, automotive and energy industries owing to its extraordinary thermomechanical properties. It is also notoriously a difficult-to-cut material, due to its short tool life and low productivity in machining operations. Despite significant progress in cutting tool technologies, the machining of Inconel 718 is still considered a grand challenge.This paper provides a comprehensive review of recent advances in machining Inconel 718. The progress in cutting tools’ materials, coatings, geometries and surface texturing for machining Inconel 718 is reviewed. The investigation is focused on the most adopted tool materials for machining of Inconel 718, namely Cubic Boron Nitrides (CBNs), ceramics and coated carbides. The thermal conductivity of cutting tool materials has been identified as a major parameter of interest. Process control, based on sensor data for monitoring the machining of Inconel 718 alloy and detecting surface anomalies and tool wear are reviewed and discussed. This has been identified as the major step towards realising real-time control for machining safety critical Inconel 718 components. Recent advances in various processes, e.g. turning, milling and drilling for machining Inconel 718 are investigated and discussed. Recent studies related to machining additively manufactured Inconel 718 are also discussed and compared with the wrought alloy. Finally, the state of current research is established, and future research directions proposed.<br/

    Future research directions in the machining of Inconel 718

    Get PDF
    Inconel 718 is the most popular nickel-based superalloy, extensively used in aerospace, automotive and energy industries owing to its extraordinary thermomechanical properties. It is also notoriously a difficult-to-cut material, due to its short tool life and low productivity in machining operations. Despite significant progress in cutting tool technologies, the machining of Inconel 718 is still considered a grand challenge.This paper provides a comprehensive review of recent advances in machining Inconel 718. The progress in cutting tools’ materials, coatings, geometries and surface texturing for machining Inconel 718 is reviewed. The investigation is focused on the most adopted tool materials for machining of Inconel 718, namely Cubic Boron Nitrides (CBNs), ceramics and coated carbides. The thermal conductivity of cutting tool materials has been identified as a major parameter of interest. Process control, based on sensor data for monitoring the machining of Inconel 718 alloy and detecting surface anomalies and tool wear are reviewed and discussed. This has been identified as the major step towards realising real-time control for machining safety critical Inconel 718 components. Recent advances in various processes, e.g. turning, milling and drilling for machining Inconel 718 are investigated and discussed. Recent studies related to machining additively manufactured Inconel 718 are also discussed and compared with the wrought alloy. Finally, the state of current research is established, and future research directions proposed.<br/

    Development of a virtual sensor for the comparison of heat partitions in milling under cryogenic cooling lubrication and high-pressure cutting fluid supply

    Get PDF
    Manufacturing high precision and high performance parts in aerospace, automotive and medical industries often requires machining of difficult-to-cut materials such as titanium, nickel and hardened alloyed steel alloys. Low productivity and environmental damage are major problems in cutting these materials, which vitally require optimized cooling strategies. High-pressure cutting fluid supply (HP CF) and cryogenic cooling lubrication (CRYO CL) are two of the most effective cooling lubrication approaches to increase tool life, productivity and avoid scrap production. The scientific and knowledge-based application of HP CF and CRYO CL had a pivotal role in improving the machining of difficult-to-cut materials, specifically in milling processes. In this context, the quantification of the cooling and lubrication effect of HP CF and CRYO CL is essential in order to adapt to the fluctuating heat generation at the cutting zone. The novel concept of a soft sensor for the quantification of the cooling and lubrication effect in the milling process is presented in this paper. This soft sensor integrates force measurements and transient temperature data from the process with the help of a mechanical model as well as an inverse temperature model. These models elevate the measured force and temperature signals to heat flows and power in the thermodynamic domain enabling an energy balancing in the real milling application. A telemetry system was used to measure the transient temperature in the milling tool with embedded thermocouples when milling 42CrMo4 and Ti-6Al-4V in αβ and β conditions. This way the separated cooling versus lubrication effect of high-pressure cutting fluid supply and a single channel cryogenic cooling lubrication based on carbon dioxide (CO2) and oil is investigated and compared with dry machining at various cutting parameters and proceeding tool wear

    Clozapine's multiple cellular mechanisms: What do we know after more than fifty years? A systematic review and critical assessment of translational mechanisms relevant for innovative strategies in treatment-resistant schizophrenia

    Get PDF
    Almost fifty years after its first introduction into clinical care, clozapine remains the only evidence-based pharmacological option for treatment-resistant schizophrenia (TRS), which affects approximately 30% of patients with schizophrenia. Despite the long-time experience with clozapine, the specific mechanism of action (MOA) responsible for its superior efficacy among antipsychotics is still elusive, both at the receptor and intracellular signaling level. This systematic review is aimed at critically assessing the role and specific relevance of clozapine's multimodal actions, dissecting those mechanisms that under a translational perspective could shed light on molecular targets worth to be considered for further innovative antipsychotic development. In vivo and in vitro preclinical findings, supported by innovative techniques and methods, together with pharmacogenomic and in vivo functional studies, point to multiple and possibly overlapping MOAs. To better explore this crucial issue, the specific affinity for 5-HT2R, D1R, α2c, and muscarinic receptors, the relatively low occupancy at dopamine D2R, the interaction with receptor dimers, as well as the potential confounder effects resulting in biased ligand action, and lastly, the role of the moiety responsible for lipophilic and alkaline features of clozapine are highlighted. Finally, the role of transcription and protein changes at the synaptic level, and the possibility that clozapine can directly impact synaptic architecture are addressed. Although clozapine's exact MOAs that contribute to its unique efficacy and some of its severe adverse effects have not been fully understood, relevant information can be gleaned from recent mechanistic understandings that may help design much needed additional therapeutic strategies for TRS

    Correction: A Guideline and Checklist for Initiating and Managing Clozapine Treatment in Patients with Treatment-Resistant Schizophrenia

    Get PDF
    This article was published online on June 27, 2022. An error was subsequently identified in the article, and the following correction should be noted: In the original publication, section 4.6, page 667, the reference cited in the first full sentence in column 2 and in Table 5 on the same page that read: “This information can be used to optimize clozapine dosage (Table 5) [103].” “Table 5 Therapeutic drug monitoring (TDM)-informed decision-making algorithm for clozapine-treated patientsa [103]” “Adapted by permission from reference [103]” Should read: “This information can be used to optimize clozapine dosage (Table 5) [104].” “Table 5 Therapeutic drug monitoring (TDM)-informed decision-making algorithm for clozapine-treated patientsa [104]” “Adapted by permission from reference [104]” The original article has been corrected. © The Author(s) 2022
    • …
    corecore