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1
Castro, Giuseppe, David Mascali, Francesco Paolo Romano, Carmen Altana, Claudia Caliri, Luigi Celona, Rossella Di Giugno, et al. "EXPERIMENTAL CHARACTERIZATION OF AN OVERDENSE PLASMA IN A COMPACT ION SOURCE." Acta Polytechnica 55, no. 3 (June 30, 2015): 146–49. http://dx.doi.org/10.14311/ap.2015.55.0146.
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<p>Electron Cyclotron Resonance Ion Sources (ECRIS) are compact plasma-based machines able to feed particle accelerators with high intensity beams of multi-charged ions. ECRIS plasmas are density-limited, since they are sustained by E.M. wave propagation up to a cut-off density value. In the past, the only way to improve ECRIS performance was to increase the microwave frequency and the magnetic field strength to satisfy the ECR condition. A different plasma heating mechanism is being applied at INFN-LNS. It is based on Electron Bernstein Waves (EBW), i.e., electrostatic waves which do not suffer any density cut-off. Highlights concerning preliminary signatures of EBW formation and subsequent absorption are given here.</p>
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Ricci, Zaccaria, Stefano Romagnoli, and Claudio Ronco. "High Cut-off Membranes in Acute Kidney Injury and Continuous Renal Replacement Therapy." International Journal of Artificial Organs 40, no. 12 (November 21, 2017): 657–64. http://dx.doi.org/10.5301/ijao.5000662.
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Innovation in continuous renal replacement therapies (CRRT) utilized to treat acute kidney injury (AKI) and sepsis, has brought new machines and techniques. Part of these new advances are due to the availability of innovative biomaterials and the construction of membranes with larger pores and wide distribution of pore sizes. This includes the creation of a new generation of high cut-off membranes whose utilization in clinical practice is promising for the wide spectrum of solutes that are removed during extracorporeal therapies. However, the enlargement of pore diameters brings some loss of albumin during treatment and this effect is still under evaluation, since there is a possibility that this is detrimental for the patient. A thorough review of the available clinical literature is reported in this paper with a reappraisal of the potential application of these new technologies.
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Huang, Pei Hsing, and Yu Ting Chen. "The Applications of Mold Flow Analysis on Vibration Separation Technologies of Investment Casting Components." Applied Mechanics and Materials 472 (January 2014): 699–703. http://dx.doi.org/10.4028/www.scientific.net/amm.472.699.
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Conventionally, the investment casting components were separated from the casting pattern tree via a grinding machine to cut off ingate/inlet of the gating system. This post-treatment process may considerably increase labor and material costs. In this paper, a fatigue damage technology was proposed to separate the components in substitution for the cutting operation of traditional grinding machines. Mold flow analyses were conducted in the design of the gating system to ensure the casting quality. An actual vibration experiment of the casting pattern tree was conducted, and the results verified that the substitutive scheme is feasible.
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Sari, Diana Puspita, and Mukhammad Faizal Ridho. "EVALUASI MANAJEMEN PERAWATAN DENGAN METODE RELIABILITY CENTERED MAINTENANCE (RCM) II PADA MESIN BLOWING I DI PLANT I PT. PISMA PUTRA TEXTILE." J@ti Undip : Jurnal Teknik Industri 11, no. 2 (June 24, 2016): 73. http://dx.doi.org/10.14710/jati.11.2.73-80.
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PT. Pisma Putra Textile adalah perusahaan yang bergerak di bidang pemintalan benang yang memiliki berbagai macam mesin produksi yang cukup sering mengalami kerusakan ketika digunakan pada proses produksi. Oleh karena itu, dibutuhkan kebijakan perawatan optimal yang dapat mengurangi frekuensi kerusakan dan menurunkan biaya perawatan mesin.. Metode yang diterapkan pada penelitian ini adalah Reliability Centered Maintenance (RCM) II. Penelitian difokuskan pada mesin Blowing I, karena memiliki downtime tertinggi. Berdasarkan frekuensi kerusakan mesin komponen yang paling sering rusak yaitu flat belt dan apron berpaku. Perawatan yang diperlukan dilakukan pada permukaan belt bergelombang, belt putus, kayu apron patah, dan paku-paku apron patah dengan scheduled discard task dengan interval perawatan dan Total Cost optimal berurutan yaitu 580 jam dengan TC Rp. 14661546,36, 465 jam dengan TC Rp 18350303,77, 490 jam dengan TC Rp 18966057,60, dan 450 jam dengan TC Rp 13419317,27. Sedangkan perawatan untuk kerusakan karet kendor adalah scheduled restoration task dengan interval perawatan 340 jam dan TC Rp 16338431,41. Total penurunan biaya keseluruhan sebesar Rp 21.587.975,45 atau 20,89% dari biaya perawataan perusahaan. Abstract PT. Pisma Putra Textile is a yarn spinning company which have various production machines which often breakdown on production process. So, the company should have optimum maintenance policy which could reduce breakdown frequency and maintenance cost. The methods which applied in this research is Reliability Centered Maintenance (RCM). Based on data which was given, it shows that Blowing I Machine have the highest downtime so the research focuses on Blowing I Machine. Based on data which was given, it shows that Blowing I Machine have the highest downtime so the research focuses on Blowing I Machine. Based on machine’s breakdown frequency and total downtime, the results shows that the critical components on Blowing I Machine are flat belt and Apron berpaku component. Based on maintenance interval analysis and optimum total cost shows that maintenance for bumpy flat belt surface, flat belt cut-off, spike lattice wood cut-off, spike lattice cut-off with scheduled discard task is 580 hours and Rp 14.661.546,36 ; 465 hours and Rp. 18.350.303,77 ; 490 hours and Rp. 18.966.057,6 ; 450 hours and Rp. 13.419.317,27 respectively. Then, maintenance interval analysis and optimum total cost for flat belt looses with scheduled restoration task is 340 hours and Rp. 16.338.431,41. So, there's a reduction cost Rp. 21.587.975,45 or 20,89% lower than the company's maintenance cost.
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Kuleshkov, Yuri V., Timofey V. Rudenko, Mikhailo V. Krasota, Miroslav Bošanský, and František Tóth. "Performance Features of Tooth Gearing in Gear Hydraulic Machines." Acta Technologica Agriculturae 24, no. 2 (May 21, 2021): 84–91. http://dx.doi.org/10.2478/ata-2021-0014.
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Abstract The paper presented determines that the rotation velocities of gears and radii connecting the axes of rotation of the gears with the point of their teeth gearing are not equal with each other. It is explained by the relative slip of involute gear profiles during their rolling. This phenomenon will become a prerequisite for further development of creation of mathematical models in the context of theory of gear hydraulic machines. The models can explain a number of specific phenomena in the operation of gear hydraulic machines, such as pressure and input pulsations, dynamics of hydraulic oil in the cut-off plane, combined torque pulsations in gear hydraulic motors and others.
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Morales, Maria-Aurora, Renato Prediletto, Giuseppe Rossi, Giosuè Catapano, Massimo Lombardi, and Daniele Rovai. "Routine Chest X-ray: Still Valuable for the Assessment of Left Ventricular Size and Function in the Era of Super Machines?" Journal of Clinical Imaging Science 2 (May 23, 2012): 25. http://dx.doi.org/10.4103/2156-7514.96540.
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Objectives: The development of technologically advanced, expensive techniques has progressively reduced the value of chest X-ray in clinical practice for the assessment of left ventricular (LV) dilatation and dysfunction. Although controversial data are reported on the role of this widely available technique in cardiac assessment, it is known that the cardio-thoracic ratio is predictive of risk of progression in the NYHA Class, hospitalization, and outcome in patients with LV dysfunction. This study aimed to evaluate the reliability of the transverse diameter of heart shadow [TDH] by chest X-ray for detecting LV dilatation and dysfunction as compared to Magnetic Resonance Imaging (MRI) performed for different clinical reasons. Materials and Methods: In 101 patients, TDH was measured in digital chest X-ray and LV volumes and ejection fraction (EF) by MRI, both exams performed within 2 days. Results: A direct correlation between TDH and end-diastolic volumes (r = .75, P<0.0001) was reported. TDH cut-off values of 14.5 mm in females identified LV end-diastolic volumes >150 mL (sensitivity: 82%, specificity: 69%); in males a cut-off value of 15.5 mm identified LV end-diastolic volumes >210 mL (sensitivity: 84%; specificity: 72%). A negative relation was found between TDH and LVEF (r = -.54, P<0.0001). The above cut-off values of TDH discriminated patients with LV systolic dysfunction – LVEF <35% (sensitivity and specificity: 67% and 57% in females; 76% and 59% in males, respectively). Conclusions: Chest X-ray may still be considered a reliable technique in predicting LV dilatation by the accurate measurement of TDH as compared to cardiac MRI. Technologically advanced, expensive, and less available imaging techniques should be performed on the basis of sound clinical requests.
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Schellinck, Tony, Tracy Schrans, Heather Schellinck, and Michael Bliemel. "Instrument Development for the FocaL Adult Gambling Screen (FLAGS-EGM): A Measurement of Risk and Problem Gambling Associated with Electronic Gambling Machines." Journal of Gambling Issues, no. 30 (May 1, 2015): 174. http://dx.doi.org/10.4309/jgi.2015.30.8.
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Previous research, based on a survey of 374 electronic machine gamblers living in Ontario, Canada, led to the selection of statements and the creation of ten constructs for the development of a new instrument, the FocaL Adult Gambling Screen for Electronic Gambling Machines (FLAGS-EGM). In this study, we used the Partial Least Squares Path Analysis form of Structural Equation Modelling to produce a hierarchical set of the ten constructs with proven predictive power for problem gambling. Receiver Operating Characteristic analysis identified cut off values for all of the constructs that predicted the target values with the desired degree of accuracy. Active gamblers were placed in five categories: No Detectable Risk, Early Risk, Intermediate Risk, Advanced Risk and Problem Gamblers. As described here, the FLAGS-EGM instrument has the potential to be applied in many situations in which identification of at-risk EGM gamblers is needed.
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Starovoitov, Nikolai Andreyevich. "EXPERIMENTAL STUDIES OF THE EFFICIENCY OF MAINTAINING CONSTANT CUTTING SPEED ON ABRASIVE CUT-OFF MACHINES WITH A ROTATING SPINDLE ASSEMBLY." Вестник Белорусско-Российского университета, no. 3 (2019): 84–92. http://dx.doi.org/10.53078/20778481_2019_3_84.
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González-Ibáñez, A., M. N. Aymamí, S. Jiménez, J. M. Domenech, R. Granero, and M. R. Lourido-Ferreira. "Assessment of Pathological Gamblers Who Use Slot Machines." Psychological Reports 93, no. 3 (December 2003): 707–16. http://dx.doi.org/10.2466/pr0.2003.93.3.707.
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The aim of the present study was to classify pathological gamblers based on their psychopathology as related to the variable sensation-seeking, and to check possible differences between the groups on the sociodemographic variables. The sample was composed of 110 male pathological gamblers using slot machines who requested treatment at the Pathological Gambling Unit at the Ciutat Sanitària i Universitària de Bellvitge. It was observed that pathological gamblers comprise three clusters, differentiated with differing severity depression, psychoticism, somatization, impulsiveness, interpersonal sensitivity, and phobic anxiety. Cluster 1, representing 46.7% of the sample, showed mean scores higher than or equal to T = 63. On the subscales of Depression, Psychoticism, Interpersonal Sensidvity, Phobic Anxiety, and Obsessiveness–Compulsiveness the score was close to T = 63 (the clinical cut-off score). Cluster 2, representing 23.8% of the sample, scored higher than Cluster 1 on the following subscales: Depression, Phobic Anxiety, Interpersonal Sensitivity, Psychoticism, Obsessive–Compulsive, and Somatization. On Cluster 3 highest mean scores were observed on all SCL-90-R dimensions relative to the other two groups. What distinguished these subgroups is not symptomatology but the severity of the psychopathology. On the other hand, sensation seeking was similar for the three clusters, and the slight differences depended on the subjects' psychopathology.
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Giuffrè, Mauro, Michela Giuricin, Deborah Bonazza, Natalia Rosso, Pablo José Giraudi, Flora Masutti, Stefano Palmucci, et al. "Optimization of Point-Shear Wave Elastography by Skin-to-Liver Distance to Assess Liver Fibrosis in Patients Undergoing Bariatric Surgery." Diagnostics 10, no. 10 (October 7, 2020): 795. http://dx.doi.org/10.3390/diagnostics10100795.
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Background: Obesity is a primary limiting factor in liver stiffness measurement (LSM). The impact of obesity has always been evaluated in terms of body mass index (BMI), without studying the effects of skin-to-liver distance (SLD) on LSM. We studied the impact of SLD on LSM in a cohort of obese patients undergoing bariatric surgery and intra-operatory liver biopsy. Materials and Methods: 299 patients underwent LSM by point-shear wave elastography (ElastPQ protocol), with two different ultrasound machines. SLD was measured as the distance between the skin and the liver capsule, perpendicular to where the region of interest (ROI) was positioned. We used the following arbitrary cut-offs: <5.7 kPa, F0–1; 5.7–7.99 kPa, F2; ≥8 kPa, F3–4. Results: We developed two logistic regression models using elastography–histology agreement (EHA) as the dependent variable and SLD as the independent variable. The model based on the second machine showed strongly more performant discriminative and calibration metrics (AIC 38.5, BIC 44.2, Nagelkerke Pseudo-R2 0.894, AUROC 0.90). The SLD cut-off value of 34.5 mm allowed a correct EHA with a sensitivity of 100%, a specificity of 93%, negative predictive value of 100%, positive predictive value of 87%, an accuracy of 96%, and positive likelihood ratio of 3.56. Conclusion: The impact of SLD is machine-dependent and should be taken into consideration when interpreting LSM. We believe that our findings may serve as a reference point for appropriate fibrosis stratification by liver elastography in obese patients.
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Anniza, Meiza, Ketut Tirtayasa, and I. Made Muliarta. "PENAMBAHAN ALAS MESIN DAN PEMBERIAN PEREGANGAN DINAMIS DI BAGIAN PROSES PEMOTONGAN SINGKONG MENURUNKAN BEBAN KERJA, KELUHAN MUSKULOSKELETAL, DAN MENINGKATKAN PRODUKTIVITAS KERJA PADA INDUSTRI KERIPIK SINGKONG." Jurnal Ergonomi Indonesia (The Indonesian Journal of Ergonomic) 3, no. 1 (June 30, 2017): 29. http://dx.doi.org/10.24843/jei.2017.v03.i01.p04.
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Cassava cutting machine is a tool to cut the cassava into thin sheets with a thickness of 1 to 2 mm. High base of work cassava cutting machine is under worker’s elbow height. So during the work, the workers took the cassava to put into the machine by means of bending and putting cassava to cutting machine one by one until the cassava is cut off. Ergonomics intervention is making an additional pad on cassava cutting machine. The purpose of this research was to prove the effect of adding pad machines and the provision of dynamic stretching at the cutting process of cassava reduce the workload, musculoskeletal disorders, and increasing work productivity at cassava chips industry.
Research was conducted by the same design subject (treatment by subjects design) with a sample of nine workers. Workload by measured the pulse of the workers. Musculoskeletal disorders measured by nordic body map questionnaire, and productivity is measured by a comparison between the results of cuts cassava production is divided workload multiplied working time. Data analyzed by t - paired with a significant level of p <0.005.
The analysis showed after adding pad machine occurs a significant difference (p <0.05) between before and after treatment: (1) decreases in workload of workers from 102.41 beats per minute become 95.51 beats per minute, (2) decrease musculoskeletal disorders from the average score of 33.56 into 31.56, and (3) increase work productivity from 1.64 to 3.58.
It was concluded that the addition of base support and the provision of dynamic stretching at the process of cutting cassava reduce the workload, musculoskeletal disorders, and increasing work productivity in cassava chips industry. It is suggested in the effort to reduce the workload, musculoskeletal disorders, as well as increasing work productivity in cassava cutting workers so it is suggested to addition of base support and do dynamic stretching movements.
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Ovsyannikov, V. E., and V. I. Vasilyev. "DETAILS’ REPAIR OF CONSTRUCTION AND ROAD MACHINES: FLUCTUATIONS’ MODELLING." Russian Automobile and Highway Industry Journal 16, no. 5 (November 2, 2019): 534–42. http://dx.doi.org/10.26518/2071-7296-2019-5-534-542.
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Introduction. Hole details are quite widely used in structures of construction and road machines. The specialists apply boring for draft, semi-fair, and in some cases for fair processing of such surfaces. This type of processing is often followed by the negative nature of oscillatory processes that leads to decrease in accuracy and in the surface quality. The paper studies the possibility of the calculation method’s usage in oscillatory processes, which allows assigning the cutting modes by providing required output parameters.Materials and methods. The authors used the double-support beam as a design model of a boring cutter. The solution of the fluctuations’ modeling came down to definition of point movements, which corresponded to cutter top (points of application equally effective cutting forces). The authors made the definition of movements with use of Mor integrals. Therefore, the paper considered the impact of chip formation and separation due to perturbing forces.Results. The authors carried out the calculation of forces’ values in cutting with use of the degree dependences. Moreover, the authors accepted the formation’s frequency as the frequency of the perturbing influenced structure. The frequency of the chip formation was defined on the basis of estimated dependences, which connected parameters of the tool, the cut-off layer and modes of cutting. As a result, the author received the implementations of oscillatory processes and studied the influence of different factors on vibration amplitude.Discussion and conclusions. The authors make assessment of the received results’ adequacy by comparison with experimental data. The error doesn’t exceed 20%. The developed model considers geometrical parameters of the tool (a departure, plate corners, etc.), the modes of cutting both mechanical properties of the processed material and parameters of the chip formation. The model can be used both at design of boring operations and by optimization of the cutting modes for the purpose of productivity increase.
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R.R Mohan, K., G. Vennela, M. Sai Kumar, Ch Satya Srinivas, and A. Harsha. "C Ran Towards 5g Networks in Virtual Environment." International Journal of Engineering & Technology 7, no. 2.7 (March 18, 2018): 441. http://dx.doi.org/10.14419/ijet.v7i2.7.10859.
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Cloud radio access network is an adaptable mobile network architecture with exponential development of portable traffic and the prerequisites of up and coming administrations are further pushing the cut-off points on current versatile systems; subsequently, overall research interests have moved toward 5G world that view which can address many challenges that mobile operators confront while attempting to support ever-growing end-user’s needs towards 5th generation of mobile networks. Be that as it may, 5G systems are most certainly not to be sent until 2020; subsequently, there is a requirement for answers for address expanding requests of current systems, without acquiring colossal expenses on administrators. This paper proposes on-request organization of portable little cells, utilizing either client versatile handsets or remote radio units and non-aware power utilization of different hosts and virtual machines.
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Ali Saare, Murtaja, Azham Hussain, and . "Successful Aging among Older Adults Using Computers: a Systematic Review." International Journal of Engineering & Technology 7, no. 3.20 (September 1, 2018): 50. http://dx.doi.org/10.14419/ijet.v7i3.20.18730.
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Recently, most of the previous studies focused on technology use and adoption among adults. However, few studies have been conducted on older adults. More specifically the emphasis is on the problems in different areas i.e. health care, housing, education, employment, and product design. Therefore, in this study, a systematic literature is taken into account where it includes multiple databases with a cut-off starting point of 2007 to 2017 that empirically examined predictors of successful aging of older adults to investigate current empirical studies. This study found that the use technology such as automatic teller machines (ATM) or VCRs are the predictor of use of computers. Moreover, older adults are likely to adopt to new technology when they recognize potential benefits. It is expected that the consolidated literature will serves as a guideline for future studies.
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Liu, Tianyun, Diqun Yan, Rangding Wang, Nan Yan, and Gang Chen. "Identification of Fake Stereo Audio Using SVM and CNN." Information 12, no. 7 (June 28, 2021): 263. http://dx.doi.org/10.3390/info12070263.
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The number of channels is one of the important criteria in regard to digital audio quality. Generally, stereo audio with two channels can provide better perceptual quality than mono audio. To seek illegal commercial benefit, one might convert a mono audio system to stereo with fake quality. Identifying stereo-faking audio is a lesser-investigated audio forensic issue. In this paper, a stereo faking corpus is first presented, which is created using the Haas effect technique. Two identification algorithms for fake stereo audio are proposed. One is based on Mel-frequency cepstral coefficient features and support vector machines. The other is based on a specially designed five-layer convolutional neural network. The experimental results on two datasets with five different cut-off frequencies show that the proposed algorithm can effectively detect stereo-faking audio and has good robustness.
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Lahdelma, S. "On the use of jerk and snap in condition monitoring of machinery – review and case studies." Insight - Non-Destructive Testing and Condition Monitoring 63, no. 8 (August 1, 2021): 457–64. http://dx.doi.org/10.1784/insi.2021.63.8.457.
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The time derivatives of acceleration offer a great advantage in detecting impact-causing faults at an early stage in condition monitoring applications. Defective rolling bearings and gears are common faults that cause impacts. This article is based on extensive real-world measurements, through which large-scale machines have been studied. Numerous laboratory experiments provide additional insight into the matter. A practical solution for detecting faults with as few features as possible is to measure the root mean square (RMS) velocity according to the standards in the frequency range from 10 Hz to 1000 Hz and the peak value of the second time derivative of acceleration, ie snap. Measuring snap produces good results even when the upper cut-off frequency is as low as 2 kHz or slightly higher. This is valuable information when planning the mounting of accelerometers.
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Frutig, Fritz, Oliver Thees, Peter Ammann, Peter Lüscher, and Peter Rotach. "Holzerntekosten und Mindererlöse bei verschiedenen Rückegassenabständen in Fichtenbeständen." Schweizerische Zeitschrift fur Forstwesen 167, no. 2 (February 1, 2016): 64–72. http://dx.doi.org/10.3188/szf.2016.0064.
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Timber harvesting costs and losses for different spacing of skid roads in spruce forests Skid roads are essential to prevent negative impacts of heavy machines on soil fertility and timber growth. Today, skid roads are frequently laid out with a spacing of 20 m because modern harvesters can reach and cut trees as far as 10 m. Skid roads not only use up space which is no longer available for production, they also have negative effects on the growth of adjacent trees due to soil compaction and root damage caused by the passage of forestry machines. Damaged roots will eventually cause butt rot and reduce the amount of valuable timber. A narrow spacing of skid roads thus leads to reduced volume and value production in the long run. In the short run, on the other hand, wider spacing will result in higher costs of timber harvesting and in a higher number of damaged trees since a number of trees need to be cut and pre-delivered manually. In this paper we calculated the advantages and disadvantages of different spacings of skid roads in a spruce stand for various scenarios of negative impacts of soil compaction, root damage and butt rot frequencies. Our results indicate that the losses due to reduced growth and a lower amount of valuable timber may be quite important if they are calculated over a whole rotation period. So, it may pay off to use wider spacing in the long run and to accept higher harvesting costs in the short run. Optimal distances for skid roads could be in the range of 30 to 50 m.
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Bartenev, Ivan, A. Petkov, and M. Popov. "ANALYSIS OF WORKING PROCESSES OF ROTORS-THROWERS OF FOREST-FIRE SOIL METERS-STRIP-LAYING MACHINES." Actual directions of scientific researches of the XXI century: theory and practice 8, no. 1 (October 26, 2020): 23–28. http://dx.doi.org/10.34220/2308-8877-2020-8-1-23-28.
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The main requirements for carrying out preventive and forest fire works are revealed. It is established that the main drawback of the used soil-sweeping machines is the small amount of soil supplied, its distribution over a large area by a small layer. This is ineffective when extinguishing a fire. Also a disadvantage is the low performance due to the low speed of the machine (up to 2 km / h). The main ways to improve the efficiency of working processes of forest fire engines and tools are considered. The working processes of new designs of soil-sweeping machines with preliminary preparation of the soil shaft before the thrower cutters are considered. Milling of the fed soil is excluded from the working process of the blade of the thrower cutter. This function is performed by spherical disks mounted on the front. In addition, the disks form a soil shaft for subsequent throwing by the rotor. But this innovation did not improve performance. Fire extinguishing is ineffective due to the strong dispersion of the soil in a thin layer, as well as the loss of volume of the ejected soil when dust is formed. The proposed method of extinguishing a low-level fire involves the formation of a shaft of loosened soil above the ground and throwing it into the fire zone. In the process, a layer of soil is cut off, then raised and divided into separate layers. At the same time, moving soil layers have different trajectories and different speeds when entering the zone of fire movement. At the same time, it is covered with a certain layer of soil, which is necessary for extinguishing a ground forest fire at a high speed.(patent no. 2706040).
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Bhaskara, Braghmandaru Adhi, Rano Irmawan, Lucia Kris Dinarti, and Hasanah Mumpuni. "Diagnostic Values of P-Wave Dispersion to Detect Diastolic Function in Patient with Hypertension." ACI (Acta Cardiologia Indonesiana) 3, no. 2 (February 28, 2018): 71. http://dx.doi.org/10.22146/aci.33574.
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Background: Hypertension is one of the main causes of cardiovascular disease. Patients with hypertension have increase risk of heart failure compared to populations with normal blood pressure. Clinical evidence shows diastolic dysfunction (DD) can lead to heart failure. Diagnostic of DD with echocardiography is important but access to echocardiography machines is limited compared to electrocardiography (ECG). ECG research correlates P-wave dispersion (PWD) with DD. The aim of this study is to determine the value of PWD to diagnose DD in patients with hypertension.Methods: A cross sectional study was conducted in patients with hypertension at Dr. Sardjito Hospital. Patients received echocardiography, ECG, blood pressure measurement and data recording. The diastolic dysfunction was determined based on 2016 ASE/EACVI criteria. We conducted ROC analysis to determine the cut-off point of P-wave dispersion and the area under the curve (AUC) value, and bivariate analysis on demographic and clinical factors related to PWD. Multivariate analysis was performed to determine the independent factors affecting PWD.Results: 113 patients met the criteria of the study subjects, with 47 men (37.2%), mean age 58.32±11.17 years. Thirteen (11.5%) subjects had DD and 37 subjects (32.7%) with increased PWD. Results showed increased PWD above 71.4 m.s with AUC 76.2%, sensitivity 75%, specifcity 72.2%, positive predictive value 33.3%, negative predictive value 96%, and accuracy of 72.5% in diagnosing DD.Conclusion: This is the frst study to examine the diagnostic value of PWD to detect diastolic function based on 2016 ASE/EACVI criteria. We found PWD above cut-off point 71.4 m.s has a moderate diagnostic value for detecting DD in patients with hypertension.
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Skoczylas, Agnieszka, and Kazimierz Zaleski. "Effect of Centrifugal Shot Peening on the Surface Properties of Laser-Cut C45 Steel Parts." Materials 12, no. 21 (November 5, 2019): 3635. http://dx.doi.org/10.3390/ma12213635.
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This article presents the results of experimental studies of the impact of centrifugal shot peening parameters on the roughness, microstructure, and microhardness of the surface layer of laser-cut C45 steel parts. Residual stress distributions and the presence of iron oxides on the surface of these elements were also examined. Centrifugal shot peening tests were performed on an FV-580a vertical machining center while using a specially designed peening head. The parameters that were varied during centrifugal shot peening included tangential speed of the tool vg and feed rate vf. The use of centrifugal shot peening for finish machining of laser-cut C45 steel parts allowed for obtaining a four-fold reduction in the surface roughness parameters Ra and Rz. As a result of shot peening, the geometrical structure of the surface of the steel parts was modified and it acquired new beneficial features, such as large values of the rounding radii of the micropeaks and high material ratios (Rmrmax = 92%). At the same time, the surface layer was hardened (microhardness increased by 16%) and a compressive residual stress layer was produced on the surface of the workpieces. Additionally, as the shot impacted the processed surface, combustion products were “blasted” or “sheared” off it. Shot peening using the proposed technique can be successfully performed while using CNC machines.
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ABLYAZ, TIMUR RIZOVICH, and KARIM RAVILEVICH MURATOV. "THE TECHNOLOGICAL QUALITY CONTROL OF STACK CUTTING BY WIRE ELECTRICAL DISCHARGE MACHINING." Surface Review and Letters 24, no. 05 (October 19, 2016): 1750060. http://dx.doi.org/10.1142/s0218625x17500603.
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Electrical discharge machining (EDM) of a stack allows achieving high precision and quality of cut surfaces and, therefore, this method is indispensable for state-of-the-art mechanical engineering. The procedure of EDM is carried out with wire-cutting machines. The characterization of constructive parameters of a stack of material and applying of an efficient cutting regime are the most important preconditions providing high precision of EDM. The goal of this work is the improvement of quality and efficiency of wire electrical discharge machining (WEDM) technology by theoretical and experimental studies of the WEDM process. The subsequent development of theoretical and empirical models allowing for the calculation of the quality parameters of treated surfaces is realized. It is shown that the main characteristics of cut surfaces are the roughness, size precision, error profile and structure of a surface layer. For the first time, the regression dependencies between the main parameters of the WEDM process (pulse [Formula: see text]-time [Formula: see text], off-time [Formula: see text], the height of the stack and the physicomechanical properties of the cut materials are obtained. The experimental study of WEDM confirms the results of mathematical modeling. It is proved experimentally that at an interlayer gap higher than 0.1[Formula: see text]mm, the cutting process stability is decreasing whereas the probability of the electrode fracture is increasing. However, it is found that at [Formula: see text]s and [Formula: see text]s, a stable cutting regime leading to bundling of the stock materials made from steel 65Γ can be realized.
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Geels, K., and M. Rückert. "Comparison between constant force and constant rate of feed in materialographic cut-off machines: Surface quality in relation to cutting speed, force, and rate of feed." Materials Characterization 36, no. 4-5 (April 1996): 225–33. http://dx.doi.org/10.1016/s1044-5803(96)00054-x.
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Kalchenko, Volodymyr, Dmytro Kalchenko, Volodymyr Venzhega, and Sergiy Ryabov. "ПІДВИЩЕННЯ ТОЧНОСТІ ТА ПРОДУКТИВНОСТІ ОБРОБКИ ТОРЦІВ РОЛИКІВ ПІДШИПНИКІВ КОЧЕННЯ." TECHNICAL SCIENCES AND TECHNOLOGIES, no. 3(17) (2019): 9–17. http://dx.doi.org/10.25140/10.25140/2411-5363-2019-3(17)-9-17.
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Urgency of the research. High-precision and productive machining of the ends of the rollers of the roller bearings is an urgent and important scientific and practical task, the solution of which will allow both to prolong the life of the bearings and to reduce their production, and therefore to increase the level of competitiveness of production. Target setting. The main requirements relating to the rollers of the rolling bearings are to ensure the high accuracy of size, shape, quality of end surfaces with high productivity of the machining process. Actual scientific researches and issues analysis. The main directions of improving the accuracy and productivity of two-sided grinding are to increase the rigidity of the machine-tool-tool-part system, to reduce the thermal impact, to improve the kinematic characteristics of the workpiece movement in the treatment area, to optimize the design and characteristics of grinding wheels. Uninvestigated parts of general matters defining. One of the most promising areas for improving the accuracy and productivity of the double-sided grinding process is to use the effect of crossing axes of grinding wheels and billets with special tool profiling. The purpose of the article. To analyze the factors that affect the accuracy and productivity of machining the end surfaces of parts on two-sided grinding machines and to develop a new high-performance method of processing the end surfaces of the rollers of the roller bearings, which would provide the possibility of assembly between the rolling bodies and the rings, not by a selective method. The presentation of the main material. The combined editing of the two planes of grinding wheels on two-sided grinding machines enables to obtain a larger diameter of the calibration section. In this case, the entire allowance is cut off in the area adjacent to the gauge. The calibration section at the inlet of the parts in the treatment area does not participate in cutting off the seam allowance, has high stability and at the outlet forms the final accuracy of the end surfaces. Conclusions and suggestions. The paper proposes a new high-performance method of single-pass machining of the end surfaces of the rollers of the roller bearings on two-sided grinding machines with oriented grinding wheels, which have a calibration section, which ensures high accuracy of processing. This method allows to reduce the scattering range of sizes and to go to the method of complete interchangeability when assembling the bearing units.
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Wałęsa, Krzysztof, Ireneusz Malujda, and Dominik Wilczyński. "Shaping the Parameters of Cylindrical Belt Surface in the Joint Area." Acta Mechanica et Automatica 13, no. 4 (December 1, 2019): 255–61. http://dx.doi.org/10.2478/ama-2019-0035.
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Abstract Most of the industrial machines use round-shaped drive belts for power transfer. They are often a few millimetres in diameter, and made of thermoplastic elastomer, especially polyurethane. Their production process requires the bonding step, which is often performed by butt welding, using the hot plate method. The authors have undertaken to design an automatic welding machine for this purpose. Consequently, it is required to carry out a process analysis of hot plate welding, which entails describing the dependency between technological parameters (temperature, pressure force, time) and the quality of the joint, especially the outer surface of the belt around the weld. To analyse this process in a proper way, it is necessary to describe the physical phenomena that occur in the material, during particular operations of the hot plate welding process. One of the most troublesome phenomena occurring during the welding process is removing of the flash. These round rings, placed around the weld, which remains after the joining process, are unacceptable in the finished component. The authors took an effort to design the necessary equipment for removing of the flash after welding, using some simple parts that cut off excessive material. The paper shows the three possible solutions for flash removal. They were verified experimentally, and afterwards, the best solution was chosen. Additionally, a number of analytical calculations were carried out in order to determine the maximum force value required for this operation. Results of the analytical calculations were compared with experimental results.
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Jing, Jianping, Yasufumi Takama, and Toru Yamaguchi. "Application of Fuzzy Inference Method in Printing Pressure State Expectation System." Journal of Advanced Computational Intelligence and Intelligent Informatics 10, no. 4 (July 20, 2006): 594–601. http://dx.doi.org/10.20965/jaciii.2006.p0594.
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To solve a problem in determining the printing pressure of printing machine for real-world liquid crystal display panel (LCD) production, a Printing Pressure expectation system is proposed based on a fuzzy inference method. In real-world LCD panel production, the recognition of printing pressure conditions and its control is a very important and difficult factor that influences the product quality. It is usually performed by skilled engineers, whose performance highly depends on his tacit knowledge. In the proposed system, a fuzzy inference method is employed to solve the problem. Images of the printing area are observed with cameras, from which abstract features are extracted with image processing. The output of the system is the state of printing pressure, which is divided into 3 states: EXCESSIVE PRESSURE (EP), GOOD PRESSURE (GP), and LOW PRESSURE (LP). Based on the abstract features, the state is estimated with fuzzy membership functions. The shapes of membership functions are determined based on the sampled glasses obtained in actual LCD production line. The experiments are performed with the 2000 glasses that are also printed with actual printing machines, of which the result is compared with that of skilled engineers. It is shown that the proposed system outperforms the quality of skilled engineers. The developed system is installed in actual production line, and it is expected to increase the product quality and production speed, as well as to cut off production costs.
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Bołoz, Łukasz, and Leonel F. Castañeda. "Computer-Aided Support for the Rapid Creation of Parametric Models of Milling Units for Longwall Shearers." Management Systems in Production Engineering 26, no. 4 (December 1, 2018): 193–99. http://dx.doi.org/10.1515/mspe-2018-0031.
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Abstract The cutting drums are the basic working components of many mining machines. The article focuses on differences in the design of cutting drums depending on the expected working conditions. Then, the unique calculation procedure is presented which allows to determine the load on the unit by reducing the forces acting on a single pick, taking into account the picks bent on the cut-off disc. Until now, this has been omitted in the literature. The results of the calculations for the selected cutting drum performed in MATLAB are also presented. The further section proposes to use Autodesk Inventor Professional's iLogic Tool for quick modelling of cutting drums. The principles of creating parameterized models and compositions using programming elements in the form of iLogic scripts are presented. The articles presented a ready-made units generator, taking into account the possibility to determine values of selected numerical parameters of the unit: diameter, web, number of patches and cutting pitch. The generator also allows you to select the type of pick holders, conical pick types, as well as the choice of pick system for repositioning or matching picks.
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Yezeguelian, Axel, and Askin T. Isikveren. "Methods to improve UAV performance using hybrid-electric architectures." Aircraft Engineering and Aerospace Technology 92, no. 5 (April 16, 2020): 685–700. http://dx.doi.org/10.1108/aeat-11-2019-0227.
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Purpose When comparing and contrasting different types of fixed-wing military aircraft on the basis of an energetic efficiency figure-of-merit, unmanned aerial vehicles (UAVs) dedicated to tactical medium-altitude long-endurance (MALE) operations appear to have significant potential when hybrid-electric propulsion and power systems (HEPPS) are implemented. Beginning with a baseline Eulair drone, this paper aims to examine the feasibility of retro-fitting with an Autarkic-Parallel-HEPPS architecture to enhance performance of the original single diesel engine. Design/methodology/approach In view of the low gravimetric specific energy performance attributes of batteries in the foreseeable future, the best approach was found to be one in which the Parallel-HEPPS architecture has the thermal engine augmented by an organic rankine cycle (ORC). For this study, with the outer mould lines fixed, the goal was to increase endurance without increasing the Eulair drone maximum take-off weight beyond an upper limit of +10%. The intent was to also retain take-off distance and climb performance or, where possible, improve upon these aspects. Therefore, as the focus of the work was on power scheduling, two primary control variables were identified as degree-of-hybridisation for useful power and cut-off altitude during the en route climb phase. Quasi-static methods were used for technical sub-space modelling, and these modules were linked into a constrained optimisation algorithm. Findings Results showed that an Autarkic-Parallel-HEPPS architecture comprising an ORC thermal energy recovery apparatus and high-end year-2020 battery, the endurance of the considered aircraft could be increased by 11%, i.e. a total of around 28 h, including de-icing system, in-flight recharge and emergency aircraft recovery capabilities. The same aircraft with the de-icing functionality removed resulted in a 20% increase in maximum endurance to 30 h. Practical implications Although the adoption of Series/Parallel-HEPPS only solutions do tend to generate questionable improvements in UAV operational performance, combinations of HEPPS with energy recovery machines that use, for example, an ORC, were found to have merit. Furthermore, such architectural solutions could also offer opportunity to facilitate additional functions like de-icing and emergency aircraft recovery during engine failure, which is either not available for UAVs today or prove to be prohibitive in terms of operational performance attributes when implemented using a conventional PPS approach. Originality/value This technical paper highlights a new degree of freedom in terms of power scheduling during climbing transversal flight operations. A control parameter of cut-off altitude for all types of HEPPS-based aircraft should be introduced into the technical decision-making/optimisation/analysis scheme and is seen to be a fundamental aspect when conducting trade-studies with respect to degree-of-hybridisation for useful power.
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Rehman, Shafiqur. "Offshore Wind Power Assessment on the East Coast of Saudi Arabia." Wind Engineering 29, no. 5 (September 2005): 409–19. http://dx.doi.org/10.1260/030952405775992643.
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This paper, to the best of author's knowledge, presents the first wind resource assessment for offshore-wind energy off the mainland coasts of Saudi Arabia, despite the onshore wind resource being known. The study utilized wind speed data from, in effect, an offshore meteorological station to study the annual and seasonal variation of wind speed, wind speed frequency distribution, energy yield and consequent opportunity for reduction in green house gases (GHG) emissions. These results were compared with contemporaneous data from a mainland location ∼ 10 km inland at the same longitude Energy yields were calculated using HOMER and RetScreen models. The annual mean wind measured at Abu Ali Island, the offshore location, was 5.43 m/s. This is larger than the 4.9 m/s measured over the same period at Abu Kharuf, the nearby inland location. Larger wind speeds were found in winter months than in summer months at both locations. At Abu Ali Island, the power of the wind could be extracted for 75% of the time at hub-height of 60 meters using modern wind machines of cut-in-speed 4 m/s, in comparison with 60% of time at Abu Kharuf. The prevailing wind direction was found to be North (N), North West (NNW) and North East (NNE).
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Hussein, Muataz F., and Hafidh J. Hussein. "Association of Echocardiographic Epicardial Fat Thickness and Carotid Intima Media Thickness with the Severity of Coronary Artery Disease." AL-Kindy College Medical Journal 16, no. 1 (September 4, 2020): 24–29. http://dx.doi.org/10.47723/kcmj.v16i1.185.
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Background: Coronary artery disease remains the main cause of death despite several preventive programs. Epicardial adipose tissue is a visceral fat depot of the heart located along the large coronary arteries and on the surface of ventricles and apex. Intima media thickness is commonly recognized as the initial stage in the development of atherosclerosis. The development of ultrasound machines, advances in echocardiographic devices and high resolution transducers facilitate comprehensive analysis of epicardial fat thickness (EFT) and carotid –intima media thickness (C-IMT).Aim: To investigate the relationship of echocardiographic epicardial fat thickness (EFT) and carotid –intima media thickness (C-IMT) with the severity of coronary artery disease.Methods: A cross sectional multicenter diagnostic accuracy study carried out at Ibn Al-Nafis Cardiovascular Hospital, Ibn Al- Bitar Cardiology Center and Ghazi Al-Hariri Hospital –Iraqi Center for Cardiology during the period between October 2016 and May 2017 assessing. History regarding demographic data and risk factors was taken. Two dimensional transthoracic echocardiographic measurements were done. EFT was measured from parasternal long axis view perpendicular to the right ventricular free wall. C-IMT was measured according to that recommended by the American society of echocardiography (ASE).Results: The current study demonstrated that the EFT has a direct and significant correlation with the number of involved vessels (P value ˂ 0.001, r= 0.770). The validity of EFT to discriminate between multiple vessels disease and no vessel involvement is excellent (AUC= 0.984, cut point > 8mm, sensitivity=92.9%, specificity= 93.3%). There is inverse and significant correlation between ejection fraction (EF) and three vessels disease (P value ˂ 0.001, r= -0.507). Also there is a direct and significant correlation between C-IMT and severity of CAD. ROC analysis for validity of C-IMT to discriminate between multiple vessels disease and no vessel involvement is excellent (AUC= 0.961, cut point > 1.04mm, sensitivity=92.9%. specificity=86.7%). C-IMT is fair to discriminate between single vessel disease and no vessel involvement (AUC=0.738, cut point ˃ 0.84mm, sensitivity 100%), so if correlated with age, C-IMT above 0.84 can be used as a cut off point for the prediction of CAD. Finally, EFT and C-IMT are more likely to reflect severity of CAD than their ratio.Conclusions: C-IMT and EFT are simple and reproducible parameters that can be used as a screening tool for the presence and severity of CAD especially before symptoms appearance in high risk patients
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Kazakov, Igor'. "THE INFLUENCE OF PLANT LIFTER OPERATING MODES ON THE DIGGING QUALITY OF PLANTING MATERIAL." Forestry Engineering Journal 10, no. 1 (April 6, 2020): 203–8. http://dx.doi.org/10.34220/issn.2222-7962/2020.1/16.
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One of the important indicators of the quality of planting material grown in forest nurseries is preservation of roots and the amount of soil remaining on the root system of plants when they are excavated. Machines used in forest nurseries for digging planting material do not fully meet these requirements, since soil layer is not sufficiently loosened and soil is not separated from the root systems of plants. In addition, considerable effort is required to extract plants from the soil, and part of the roots is cut off. Modern plant lifters with active working bodies enable to separate the soil from the root systems of plants and ensure safety of the required amount on them, reducing the effort to extract plants from the soil. The article presents the results of studies of the influence of plant lifter operating modes on the quality of planting material harvesting, on the basis of which the rational oscillation frequency of the levers and beats within 675 counts/min is substantiated when applying one oscillation of 5.4 cm/count and operating speed 2.2 km/h. These operation modes of plant lifter ensure the preservation of soil on the root system of enlarged spruce seedlings in the amount of 136.2 g and allowable effort to remove them from the soil within 36.4 N.
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Liu, Yong, Jun Hu, Huawen Xiao, and Elton J. Chen. "Effects of material and drilling uncertainties on artificial ground freezing of cement-admixed soils." Canadian Geotechnical Journal 54, no. 12 (December 2017): 1659–71. http://dx.doi.org/10.1139/cgj-2016-0707.
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The artificial ground freezing method can be used jointly with the deep cement mixing method during break-in and break-out processes of shield machines in a tunnel shaft. The frozen ground can fully cut off groundwater seepage, thus ensuring a watertight working platform. Cement-admixed soils can restrict frost heave and thaw-induced settlement because of the decreased permeability. Both methods can also enhance mechanical strength of the soil to enable construction to proceed. Two main sources of heterogeneity are likely to influence the freezing effect: spatial variability in in situ water content in natural soil and spatial variability in binder concentration in cement-admixed soils. Furthermore, positioning error when installing freeze pipes can also affect freezing efficiency. This study simulates in situ water content and binder concentration as Gaussian random fields, whereby variations in the thermophysical properties are estimated. Positioning error is also assessed by prescribing an incline angle in freeze pipes. The influences of those two sources of spatial variability as well as positioning error are examined with random finite-element analyses and statistical characteristics are estimated based on the results. Results are tabulated to offer practitioners a rule of thumb for estimating additional efforts needed in artificial ground freezing, accounting for variations in the thermophysical properties and positioning errors in installing freeze pipes.
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Yoshino, Masahiko, Takahiro Shirakashi, Toshiyuki Obikawa, and Eiji Usui. "Electrolytic cut-off grinding machine for composite materials." Journal of Materials Processing Technology 74, no. 1-3 (February 1998): 131–36. http://dx.doi.org/10.1016/s0924-0136(97)80136-7.
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Du, Hong Wei, and Zhong Zhi Han. "Design of Sweet Potato Vine Chopping and Returning Machine." Applied Mechanics and Materials 538 (April 2014): 214–17. http://dx.doi.org/10.4028/www.scientific.net/amm.538.214.
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Based on sweet potato vine creeping stems features and northern cropping patterns, this paper developed a sweet potato vine chopping and returning machine. It consists of pick-up mechanism, cut-off device, crushing device, ground wheel assembly and main frame etc.. The machine is attached directly to the tractor´s three-point linkage. It can complete vine picking up, cut-off, crushing and returning in one operation. The gear box which is made for turning and increasing speed is driven by PTO, and then drives cut-off system and crushing device individually. With the tractor forward, the vines was first picked up by the pick-up mechanism and cut off by the rotating disc of the cut-off device, and crushed by the crushing shaft with the help of the negative pressure caused by the high speed rotation of the crushing blade shaft.
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Fedorenko, Vyacheslav F., Vitaly E. Tarkivskiy, Nikolay P. Mishurov, and Nikolay V. Trubitsyn. "Digital Data Processing Methods for Estimating Tractive Force of Tractors." Engineering Technologies and Systems 31, no. 1 (March 30, 2021): 127–42. http://dx.doi.org/10.15507/2658-4123.031.202101.127-142.
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Introduction. When carrying out an energy assessment of agricultural machines and traction tests of tractors, the most important indicator is the value of the tractive effort. The existing methods for determining the tractive effort of tractors imply the use of specialized measuring instruments, such as strain gauges and devices for processing and displaying information. The accuracy of determining the tractive effort is significantly influenced by the physical and mechanical properties of soil. To process the useful signal during the measurement of tractive effort, the data stream of the strain gauge sensor must be subjected to additional digital filtering taking into account the operating conditions of the agricultural unit. Materials and Methods. The functions of changing the tractive effort obtained on the K-744R2 tractor in various gears have been analyzed. An algorithm for digital processing of the signal of a strain gauge force meter based on a median filter has been developed that makes it possible to increase the measurement accuracy. The advantage of the proposed method is the ability to cut off sharp short-term impulse noise and sharp fluctuations in the amplitude of the measured value. Results. A method for determining the amount of tractive effort using median signal processing has been proposed. A device for determining the tractive effort during testing of agricultural tractors and units has been developed. The choice of the main components of the device for determining the magnitude of the tractive effort has been substantiated. As a result of the research, a device for measuring and digital processing of the signal of a force meter based on a microcontroller and specialized software for processing initial data in real time was designed and manufactured. Discussion and Conclusion. The developed method makes it possible to exclude the negative effect of impulse noise arising in the process of measuring the tractive effort of the tractor. The proposed device for measuring the tractive effort of tractors is compatible at the level of the exchange protocol with existing devices, has a high speed of operation in real time, multi-channel operation.
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Amelia, Octavia Dwi, Agus M. Soleh, and Septian Rahardiantoro. "Pemodelan Support Vector Machine Data Tidak Seimbang Keberhasilan Studi Mahasiswa Magister IPB." Xplore: Journal of Statistics 2, no. 1 (June 30, 2018): 33–40. http://dx.doi.org/10.29244/xplore.v2i1.76.
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Bogor Agricultural University Postgraduate School (SPs-IPB) can maintain its reputation by applying a more selective admissions system. This research predicts the success of student using Support Vector Machine (SVM) modeling by considering the characteristics and educational background of the students. But there is an imbalance of data class. SVM modeling on unbalanced data produces poor performance with a sensitivity value of 0.00%. Unbalanced data handling using Sythetic Minority Oversampling Technique (SMOTE) succeeded in improving SVM classification performance in classifying unsuccessful students. Based on accuracy, sensitivity, and specificity with the default cut off, the exact type of SVM to model student success is SVM RBF. When using the optimum cut-off value from each type of SVM, the sensitivity value can be improved again. SVM RBF still gives the best result when using cut off 0.6. The final model that will be used to predict the success of the SPs-IPB student is obtained from SVM RBF modeling with cut off 0.6 using the entire data that has been through the SMOTE stage.
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Kumar, Pawan, Meenu Gupta, and Vineet Kumar. "Microstructural analysis and multi response optimization of WEDM of Inconel 825 using RSM based desirability approach." Journal of the Mechanical Behavior of Materials 28, no. 1 (October 1, 2019): 39–61. http://dx.doi.org/10.1515/jmbm-2019-0006.
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AbstractIncreasing demand of aerospace industry for more heat resistant and tough material have open up the possibility of the use of Inconel 825 for making of combustor casing and turbine blades. Because of its robust nature, Inconel 825 is a difficult-to-cut material with conventional methods. Wire-cut electrical discharge machining (WEDM), a non traditional method uses thermoelectric erosion principle to produce intricate shape and profiles of such difficult-to-cut material. In this study, various operating parameters of WEDM are optimized using desirability approach and microstructural behavior at optimum combinations was studied. Input parameters viz. pulse-on time, pulse-off time, peak current, spark gap voltage, wire tension, wire feed and performance has been measured in term of material removal rate, surface roughness and wire wear ratio. It has been observed that at 110 machine unit pulse-on time (Ton), 35 machine unit pulse-off time (Toff), 46 volt gap voltage (SV), 120 ampere peak current (IP), 11 machine unit wire tension (WT) and 5 m/min wire feed (WF), the values obtained for material removal rate (MRR), surface roughness (SR) and wire wear ratio (WWR) were 27.691mm2/min, 2.721 μmand 0.117 respectively. Scanning electron microscopy, energy dispersive spectrograph and X-ray diffraction analysis has also been carried out to study the surface characterization. Comparatively less numbers of cracks, pockmarks, craters, and pulled out material were found on work specimen surface and wire electrode surface under standardized conditions, thus maintaining the surface integrity of the machined surface.
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Wu, Yan, and Yan Ma. "Finite-Element Analysis of Arranging Intermediate Cuttings Tool of Circular Saw Web and Wedge Disc." Advanced Materials Research 631-632 (January 2013): 1068–72. http://dx.doi.org/10.4028/www.scientific.net/amr.631-632.1068.
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When the intermediate cuttings cut the wood, the efficiency of the vibration of the circular saw web was low so that the saw web always broke off. Moreover, the high-speed rotation would cause the vibration of the complete machine and result in the initial failure of the machine. Therefore, seeing from the problems from the analysis above and practice, the new design of the current micro intermediate cuttings seemed especially important. In the thesis, the author made a new arrangement of the micro intermediate cuttings of machinery tools, carrying out three-dimensional modeling and simulation of the complete machine and made an analysis of the dynamic cutting process by means of analyzing the working condition of circular saw web.
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Khanna, Rajesh, Neeraj Sharma, and Rahul Dev Gupta. "Investigations of the Effect of Parameters on the CR and SR during Al6063/SiC/Ti at WEDM." Applied Mechanics and Materials 895 (November 2019): 181–86. http://dx.doi.org/10.4028/www.scientific.net/amm.895.181.
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Wire electric discharge machine (WEDM) is a non-conventional machining process used to machine the hard to cut materials. WEDM has wide applications in die and punch industries, automobile, aerospace and medical industries. In this process the material is processed with the help of a wire electrode. In present work, Al6063/SiC/Ti composite was processed with the help of WEDM. As this spark-erosion machine tool have number of input process parameters, so to process any material it became mandatory to investigate the range of the machining parameters in which machine tool operate successfully. Every material represents its unique material characteristics due to which it can be machined successfully in a limited range of the parameters. Above and below this range the wire will break abruptly. So, in this present work an attempt has been made to investigate the range of the process parameters in which WEDM can process Al6063/SiC/Ti composite efficiently. The input parameters considered for the present work are pulse on-time, pulse off-time, servo voltage, peak current, wire feed and wire tension. After the experiments it was found that the pulse on-time, pulse off-time, servo voltage and wire-feed were the significant process parameters in the investigations of cutting rate and surface roughness.
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Kumar, G. Venkata Ajay, M. Shilpa, Udagave Shital Purander, G. Madhoo, and V. Asokan. "Multi-Objective Optimization of Machining Process Parameters in Wire-Cut Electric Discharge Machining of Inconel X750 Alloy by Combinatorial Approach." Materials Science Forum 969 (August 2019): 781–86. http://dx.doi.org/10.4028/www.scientific.net/msf.969.781.
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Difficult-to-cut materials, generally high hardness, strength and toughness, are generally difficult to machine in conventional machining. Also tool wear is high in conventional machining processes. Wire Cut Electric Discharge (WEDM) machining is particularly used for machining complex profiles, demanding very high accuracy. The current work focuses on the optimization of roughness of a surface that is machined using WEDM; the process parameters considered for optimization are pulse-on-time (Pon), pulse-off time (Poff), wire feedrate (WFR) and spark gap voltage (SGV). One of the surface integrity aspect is considered as surface roughness (SR) and other related to machining output considered as material removal rate (MRR) for the output responses. The paper presents, a multi-criteria decision making technique, with Grey Relational Analysis (GRA) integrated with Particle Swarm Optimization (PSO) for optimizing the process parameters. Further, confirmation tests that were conducted also validated the improvement in SR and MRR.
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Shukla, Sidharth Kumar, and Amrita Priyadarshini. "Application of Machine Learning Techniques for Multi Objective Optimization of Response Variables in Wire Cut Electro Discharge Machining Operation." Materials Science Forum 969 (August 2019): 800–806. http://dx.doi.org/10.4028/www.scientific.net/msf.969.800.
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Wire Cut Electrical Discharge Machining (WEDM) is a non-conventional thermal machining process which is capable of accurately machine alloys having high hardness or part having complex shapes that are very difficult to be machined by the conventional machining processes. The WEDM finds applications in automobiles, aero–space, medical instruments, tool and die industries, etc. The input parameters considered for WEDM are pulse on time, pulse off time, flushing pressure, servo voltage, wire feed rate and wire tension. Performance of WEDM is mainly assessed by output variables such as, material removal rate (MRR), kerf width (Kw) and surface roughness (Ra) of the work piece being machined. Looking at the need of a suitable optimization model, the present work explores the feasibility of machine learning concepts to predict optimum surface roughness and kerf width simultaneously by making use of experimental data available in the literature for machining of Hastelloy C– 276 using WEDM. In most of the literatures, single objective optimization has been carried out for predicting optimum cutting parameters for WEDM. Hence, the present work presents a methodology that makes use of a machine learning algorithm namely, gradient descent method as an optimization technique to optimize both surface roughness and kerf width simultaneously (multi objective optimization) and compare the results with the existing literatures. It was observed that the input parameters such as pulse on time, pulse off time, and peak current have significant effect on both surface roughness and kerf width. The gradient descent method was successfully used for predicting the optimum values of response variables.
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VS Ram Prasad, A., Koona Ramji, and B. Raghu Kumar. "Study of wire-electrical discharge machining parameters of titanium alloy by using taguchi method." International Journal of Engineering & Technology 7, no. 2.8 (March 19, 2018): 10. http://dx.doi.org/10.14419/ijet.v7i2.8.10316.
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Machining of Titanium alloys is difficult due to their chemical and physical properties namely excellent strength, chemical reactivity and low thermal conductivity. Traditional machining of such materials leads to formation of continuous chips and tool bits are subjected to chatter which leads to formation of poor surface on machined surface. In this study, Wire-EDM one of the most popular unconventional machining process which was used to machine such difficult-to-cut materials. Effect of Wire-EDM process parameters namely peak current, pulse-on- time, pulse-off-time, servo voltage on MRRand SR was investigated by Taguchi method. 0.25 mm brass wire was used in this process as electrode material. A surface roughness tester (Surftest 301) was used to measure surface roughness value of the machined work surface. A multi-response optimization technique was then utilized to optimize Wire-EDM process parameters for achieving maximum MRR and minimum SR simultaneously.
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Mulvaney, D. J., D. E. Newland, and K. F. Gill. "Identification of Surface Roughness." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 199, no. 4 (October 1985): 281–86. http://dx.doi.org/10.1243/pime_proc_1985_199_124_02.
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The Fourier spectral estimates of machined surface roughness data are investigated in detail, and, in particular, the shape of these estimates is examined. From these assessments, a parameter is derived which enables a description to be produced of the underlying form of spectral estimates of machined surface roughness data, without the requirement for a stylus instrument operator to select a standard cut-off filter.
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Muhammad, Riaz, Naseer Ahmed, Yasir Maqbool Shariff, and Vadim V. Silberschmidt. "Finite-Element Analysis of Forces in Drilling of Ti-Alloys at Elevated Temperature." Solid State Phenomena 188 (May 2012): 250–55. http://dx.doi.org/10.4028/www.scientific.net/ssp.188.250.
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Demand for high-strength alloys in aerospace, marine and off-shore industries has grown significantly over last decades, primarily thanks to their high strength, light weight as well as good fatigue and corrosion-resistance properties. However, these materials are extremely difficult to machine with conventional machining methods. Hot machining is an alternative technique used by many researchers for cutting of hard-to-cut materials in turning and milling operations. In this assisted machining technique, an external heat source is used to reduce shear strength of the machined workpiece, enhancing material removal of such alloys. Drilling is one of the most important and basic operations for producing cylindrical holes in machined components. In this work, a three-dimensional finite-element (FE) model of drilling process is developed in a commercial FE software DEFORM 3D. A nonlinear temperature-dependent material behaviour is incorporated in numerical simulations. The effect of an external heat source on thrust forces and torque on a drill-bit was investigated with the developed FE model. Advantages of hot drilling in reducing thrust force and torque reduction are demonstrated.
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Meena, Mahesh Kumar. "Concept of Intelligent Automation System for Electrical Energy Distribution and Utilities." International Journal for Research in Applied Science and Engineering Technology 9, no. VI (June 20, 2021): 1377–80. http://dx.doi.org/10.22214/ijraset.2021.35259.
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This system the normal street is convert into smart street means the street light are automatically on and In off according to the vehicle on that road .The main purpose of our project is to save the energy which is wasted in our streets and the smart lights are glow with high intensity when the vehicle is pass through that road otherwise it will off.In today’ s automation world ,things are updating very quickly with a simple and easy method and this automation is nothing but a easy way to reduce the man power in the production of many industries. In the industrial sector the automation is one step greater than the mechanical man power because in man power the machinery are assign by Human operators where as in automation all work are dependent on the machine. This project how the saved power can be used in many works. It is answer to all that question that how can we save energy in different ways. We conclude that if there no vehicle on the street at the night time then the lights are off and the saved energy is used where there are high lights cut off .
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Chen, Shang Kun, and Rui Fang Li. "An Analysis of Machanical Properties about the Fracture and Deformation Exiting in the Section of Round Steel with Software-SW/Simulation." Applied Mechanics and Materials 246-247 (December 2012): 733–37. http://dx.doi.org/10.4028/www.scientific.net/amm.246-247.733.
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Aim at the deformation occurred on round steel section by abscission machine, use the software-SW/simulation to make a research about the deformation mechanism existing in the fracture, we found that the round steel fracture took place first near fixed blade ‘edge and more plastic deformation centralized in the domain like "crescent shape". The result is theoretically useful for improving the section deformation and optimizing the blade structure of round steel cut-off machine.
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Li, Cheng Qun, and Chao Sun. "Study on Lock Mechanism of Coil Strapping Machine." Advanced Materials Research 476-478 (February 2012): 1468–71. http://dx.doi.org/10.4028/www.scientific.net/amr.476-478.1468.
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The thesis studies the lock body of coil binding machine. It suggests that a convertible drive lock body just need a cylinder drive to complete lock molding, pressure strip, lock, and cut off, so as to simplify the locking body structure. This paper uses the theory of mechanism to analyze the convertible drive lock body. This paper applies Creo Elements/Pro, the 3D model software, to build up lock body model and analyses its structure. This paper also analyses the key components in FEA and strength calculation, using Pro/Mechanica module.
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Neumann, Johannes T., Nils A. Sörensen, Tanja Zeller, Craig A. Magaret, Grady Barnes, Rhonda F. Rhyne, Celine Peters, et al. "Application of a machine learning-driven, multibiomarker panel for prediction of incident cardiovascular events in patients with suspected myocardial infarction." Biomarkers in Medicine 14, no. 9 (June 2020): 775–84. http://dx.doi.org/10.2217/bmm-2019-0584.
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Background: In patients with suspected myocardial infarction (MI), we sought to validate a machine learning-driven, multibiomarker panel for prediction of incident major adverse cardiovascular events (MACE). Methodology & results: A previously described prognostic panel for MACE consisting of four biomarkers was measured in 748 patients with suspected MI. The investigated end point was incident MACE within 1 year. The prognostic value of a continuous score and an optimal cut-off was investigated. The area under the curve was 0.86 for the overall model. Using the optimal cut-off resulted in a negative predictive value of 99.4% for incident MACE. Patients with an elevated prognostic score were at high risk for MACE. Conclusion: Among patients with suspected MI, we validated a multibiomarker panel for predicting 1-year MACE. Clinical Trial Registration: NCT02355457 (ClinicalTrials.gov)
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Cao, Lian Min, Qing Liang Zeng, Jing Cui, and Hong Juan Yang. "Development of Hydraulic Security Shearing Machine for the Annulus Chain Used in Coal Mine." Advanced Materials Research 282-283 (July 2011): 371–74. http://dx.doi.org/10.4028/www.scientific.net/amr.282-283.371.
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In view of the situation of shearing the scraper chain frequently and adjusting the pitch chain of the scraper conveyer in the coal mine, the project design a kind of hydraulic security shearing machine for the annulus chain of scraper conveyer, to solve the problem for high strength and heavy gauge annulus underground coal mine to cut off.
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Manoj, I. Vishal, S. Narendranath, and Alokesh Pramanik. "Optimization and Prediction of Machining Responses Using Response Surface Methodology and Adaptive Neural Network by Wire Electric Discharge Machining of Alloy-X." Materials Science Forum 1026 (April 2021): 28–38. http://dx.doi.org/10.4028/www.scientific.net/msf.1026.28.
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Wire electric discharge machining non-contact machining process based on spark erosion technique. It can machine difficult-to-cut materials with excellent precision. In this paper Alloy-X, a nickel-based superalloy was machined at different machining parameters. Input parameters like pulse on time, pulse off time, servo voltage and wire feed were employed for the machining. Response parameters like cutting speed and surface roughness were analyzed from the L25 orthogonal experiments. It was noted that the pulse on time and servo voltage were the most influential parameters. Both cutting speed and surface roughness increased on increase in pulse on time and decrease in servo voltage. Grey relation analysis was performed to get the optimal parametric setting. Response surface method and artificial neural network predictors were used in the prediction of cutting speed and surface roughness. It was found that among the two predictors artificial neural network was accurate than response surface method.
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Devarasiddappa, D., M. Chandrasekaran, and K. Palanikumar. "Taguchi Analysis of MRR and PC for Sustainable Machining of Ti6Al4V Alloy Using WEDM Process." Advances in Science and Technology 106 (May 2021): 3–9. http://dx.doi.org/10.4028/www.scientific.net/ast.106.3.
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Wire-cut electrical discharge machining (WEDM) has emerged as the most important non-traditional machining technique in the recent years due to its exceptional accuracy and capability to produce net near shape components of electrically conductive materials. Ti-6Al-4V alloy is a hard-to-machine material and popularly used in bio-medical, aerospace, automotive, defence applications etc. due to its distinct merits. In this work, Taguchi optimization technique is applied to obtain optimum cutting conditions for material removal rate (MRR) and power consumption (PC) in WEDM of Ti6Al4V alloy. The result showed 16.38% improvement in MRR and 10.36% reduction in PC at the optimal parameter settings compared to initial cutting conditions. ANOVA result established pulse off time and current as highly significant process parameters affecting MRR (I: 56.58%, Toff: 23.57%) and PC (Toff: 43.26%, I: 31.24%). The response surface variation PC and MRR is studied using 3D plots. Surface morphology of machined component using scanning electron microscope images is also discussed.