443 research outputs found

    Multi-objective optimisation for minimum quantity lubrication assisted milling process based on hybrid response surface methodology and multi-objective genetic algorithm

    Get PDF
    © 2019 by SAGE Publications Ltd.Parametric modelling and optimisation play an important role in choosing the best or optimal cutting conditions and parameters during machining to achieve the desirable results. However, analysis of optimisation of minimum quantity lubrication–assisted milling process has not been addressed in detail. Minimum quantity lubrication method is very effective for cost reduction and promotes green machining. Hence, this article focuses on minimum quantity lubrication–assisted milling machining parameters on AISI 1045 material surface roughness and power consumption. A novel low-cost power measurement system is developed to measure the power consumption. A predictive mathematical model is developed for surface roughness and power consumption. The effects of minimum quantity lubrication and machining parameters are examined to determine the optimum conditions with minimum surface roughness and minimum power consumption. Empirical models are developed to predict surface roughness and power of machine tool effectively and accurately using response surface methodology and multi-objective optimisation genetic algorithm. Comparison of results obtained from response surface methodology and multi-objective optimisation genetic algorithm depict that both measured and predicted values have a close agreement. This model could be helpful to select the best combination of end-milling machining parameters to save power consumption and time, consequently, increasing both productivity and profitability.Peer reviewedFinal Published versio

    Comparative Analysis of Downlink Packet Scheduling Algorithms in 3GPP LTE Networks

    Full text link
    Long Term Evolution (LTE) mobile network aims to support high speed network services even in highmobility scenarios. To achieve this goal, LTE adopts some advanced features in Radio Resource Management (RRM) procedures. Among them, LTE packet scheduling plays a fundamental role in maximising system performance. In this paper, a comparative analysis on the performances of Proportional Fair (PF), Exponential/Proportional Fair (EXP/PF), Exponential (EXP) Rule, MaximumLargest Weighted Delay First (M-LWDF), Logarithmic (LOG) Rule and Frame Level Scheduler (FLS) LTE downlink packet scheduling algorithms is reported. Performance is evaluated in single cell with interference environment while increasing user number and user speed. Results show that for multimedia flow, FLS scheme outperforms other five schemes in terms of packet delay, packet loss ratio, and average throughput, whereas for best-effort flow, EXP-PF scheme shows better average throughput performance on average as compared with other algorithms being considered herein

    Effect of Deposition Time on the Optical Characteristics of Chemically Deposited Nanostructure PbS Thin Films

    Get PDF
    AbstractPbS thin films are good materials for antireflection coatings and for solar thermal applications in flat-plat collectors, house heating for solar chick brooding, etc. Nanocrystalline PbS thin films were deposited on glass substrates with various deposition times using chemical bath deposition technique. The study was carried out for thicknesses in the range (500-660nm). The crystalline size of these films was studied by atomic force microscope AFM. A dense surface composed of multilayered grains of films was obtained with the crystal size around 37.67nm. The optical properties of these films have been studied and show that PbS thin films have allowed direct transition and the values of energy gap varied between (1.88-1.55eV) with increasing film thickness, The large optical band gap in the films is attributed to the quantum coefficient effect. Influences of thermal treatments under various annealing temperatures on the optical properties for some deposition films were studied

    A Case of Inferior Myocardial Infarction Complicated by Ventricular Septal Rupture Leading to Cardiogenic Shock: Tandem Heart to the Rescue!

    Get PDF
    Ventricular septal rupture (VSR) is a rare but life-threatening complication of acute myocardial infarction. We present a case of VSR-related refractory cardiogenic shock that was successfully managed with TandemHeart® followed by surgical repair

    Archaeological and geophysical survey in deserted early islamic village Al-Qusur (Failaka, Kuwait)

    Get PDF
    Failaka Island, the second largest and the only inhabited off-shore island of Kuwait, is situated 17 km east of Kuwait mainland, in the entrance to Kuwait Bay. They can be found along the shores and approximately in the middle of the island and correspond with occurrence of known archaeological sites. Failaka’s history goes back to the Bronze Age Dilmun civilization. After the decline of the occupation during the Middle Bronze Age, Failaka was again inhabited during Seleucid and post-Seleucid..

    Secure and Robust Fragile Watermarking Scheme for Medical Images

    Get PDF
    Over the past decade advances in computer-based communication and health services, the need for image security becomes urgent to address the requirements of both safety and non-safety in medical applications. This paper proposes a new fragile watermarking based scheme for image authentication and self-recovery for medical applications. The proposed scheme locates image tampering as well as recovers the original image. A host image is broken into 4Ă—4 blocks and Singular Value Decomposition (SVD) is applied by inserting the traces of block wise SVD into the Least Significant Bit (LSB) of the image pixels to figure out the transformation in the original image. Two authentication bits namely block authentication and self-recovery bits were used to survive the vector quantization attack. The insertion of self-recovery bits is determined with Arnold transformation, which recovers the original image even after a high tampering rate. SVD-based watermarking information improves the image authentication and provides a way to detect different attacked area. The proposed scheme is tested against different types of attacks such are text removal attack, text insertion attack, and copy and paste attack

    Basement membranes in obstructive pulmonary diseases

    Get PDF
    Increased and changed deposition of extracellular matrix proteins is a key feature of airway wall remodeling in obstructive pulmonary diseases, including asthma and chronic obstructive pulmonary disease. Studies have highlighted that the deposition of various basement membrane proteins in the lung tissue is altered and that these changes reflect tissue compartment specificity. Inflammatory responses in both diseases may result in the deregulation of production and degradation of these proteins. In addition to their role in tissue development and integrity, emerging evidence indicates that basement membrane proteins also actively modulate cellular processes in obstructive airway diseases, contributing to disease development, progression and maintenance. In this review, we summarize the changes in basement membrane composition in airway remodeling in obstructive airway diseases and explore their potential application as innovative targets for treatment development

    Comprehensive Study on Tool Wear During Machining of Fibre-Reinforced Polymeric Composites

    Get PDF
    © 2021 Springer-Verlag. The final publication is available at Springer via https://dx.doi.org/10.1007/978-981-33-4153-1.The use of fibre reinforced polymeric (FRP) composites has increased rapidly, especially in many manufacturing (aerospace, automobile and construction) industries. The machining of composite materials is an important manufacturing process. It has attracted several studies over the last decades. Tool wear is a key factor that contributes to the cost of the machining process annually. It occurs due to sudden geometrical damage, frictional force and temperature rise at the tool-work interaction region. Moreover, tool wear is an inevitable, gradual and complex phenomenon. It often causes machined-induced damage on the workpiece/FRP composite materials. Considering the geometry of drill, tool wear may occur at the flank face, rake face and/or cutting edge. There are several factors affecting the tool wear. These include, but are not limited to, drilling parameters and environments/conditions, drill/tool materials and geometries, FRP composite compositions and machining techniques. Hence, this chapter focuses on drilling parameters, tool materials and geometries, drilling environments, types of tool wear, mechanisms of tool wear and methods of measurement of wear, effects of wear on machining of composite materials and preventive measures against rapid drill wear. Conclusively, some future perspectives or outlooks concerning the use of drill tools and their associated wears are elucidated, especially with the advancement in science and technology.Peer reviewedFinal Accepted Versio

    Experiences Moving from Residential Camps to Non-Residential Day Camps

    Get PDF
    This paper describes a recent change in our engineering summer outreach program and how that change was enacted and perceived. Nonresidential summer camp programs are often scheduled to be delivered on successive days, meaning that the attending students interact with the camp’s curriculum, staff, and instructors daily for several consecutive days. Our College followed this model for many years, with students experiencing guided engineering activities for a block of time in the morning and a block of time after lunch. Each block was generally focused on one particular discipline-related activity. An alternate model is to schedule camp programs to be delivered one day per week over a period of multiple weeks, resulting in a weekly interaction between the students and the camp’s programming. This model was implemented for the first time during summer 2015. The camp was delivered on consecutive Fridays for a period of seven weeks and the curriculum for each Friday was designed to introduce high school rising juniors and seniors to a particular academic program in the College of Engineering. The camp was structured and marketed in such a way to allow students to register for and attend those days of interest to them and/or those days that fit within their summer schedule. During summer 2015, the total attendance across the seven days of the program was 262. This total comprised 95 individual students that attended one or more days of camp; on average, each student attended 2.8 days. Interestingly, the distribution for the number of days attended by students was bimodal and 24% of the students attended five or more days. Experiences and initial assessments of this weekly summer camp program model are described and a discussion of the advantages and disadvantages of weekly versus daily program schedules is provided.Ye

    The effectiveness of neuromuscular warm-up strategies, that require no additional equipment, for preventing lower limb injuries during sports participation: a systematic review

    Get PDF
    PMCID: PMC3408383The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1741-7015/10/75. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
    • …
    corecore