المؤلفون: Mechali, A., Mesicek, J., Ma, Q.-P., Hajnys, J., Gautam, P., Blaha, R., Krisak, D., Petru, J.

المصدر: MM Science Journal; 2024 Spl Issue, p7165-7172, 8p

مستخلص: The scientific community has been intensively studying how to improve the level of surface roughness on 3D-printed parts, particularly metallic parts made using the selective laser melting (SLM) technique. Various research papers on this subject have revealed that accurate surface roughness data can be generated using several methods that are, in fact, not cost-effective. For this reason, the finishing processes are an integral part of the overall production, especially for those components where the primary concern is not only appearance but also functional properties (e.g., lower friction, reduced noise, etc.). This work deals with the measurement of the surface roughness of tumbled parts produced with SLM after surface treatment with centrifugal and vibratory methods. Tumbling was performed with ceramic, plastic, and porcelain mediums. At the end, there is an evaluation of the measurement data based on the required surface roughness of the components. [ABSTRACT FROM AUTHOR]

: Copyright of MM Science Journal is the property of MM Science Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Posmykova, E., Hruban, J., Mesicek, J., Blaha, R., Ma, Q.-P., Hajnys, J., Petru, J.

المصدر: MM Science Journal; 2024 Spl Issue, p7173-7179, 7p

مستخلص: The aim of the article was to investigate the possibility of topological optimization (TO) of the inline skate frame manufactured through the Powder Bed Fusion (PBF) method of AISi10Mg-0403, an Additive Manufacturing (AM) technique. The study's core objective was to leverage The Altair Inspire software to re-envision the initial CAD model, culminating in an organic and bionic frame design. Incorporating comprehensive load analysis, the research considered various load scenarios, including static mass, dynamic forces, and acceleration during cornering, to ascertain the frame's strength and stability. Topological optimization was excluded within a defined design space, preserving critical functional elements while enhancing performance. The first part of the article is devoted to defining the concepts and nature of AM metallic materials. The practical part follows, in which the design of the skate frame is specified with specific requirements and the procedure of individual steps needed to create its final CAD Model. The work concludes by describing the preparation of the designed optimized frame construction. [ABSTRACT FROM AUTHOR]

: Copyright of MM Science Journal is the property of MM Science Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Deroszewska, M., Saraczyn, R., Cisowski, A., Kowaluk, T., Borowski, T., Petru, J., Myszka, D.

المصدر: Journal of Achievements in Materials & Manufacturing Engineering; Dec2023, Vol. 121 Issue 2, p289-305, 17p

المؤلفون: Ng, FS, Toman, O, Petru, J, Peichl, P, Winkle, RA, Reddy, VY, Neuzil, P, Mead, RH, Qureshi, NA, Whinnett, ZI, Bourn, DW, Shelton, MB, Kautzner, J, Sharma, AD, Hocini, M, Haïssaguerre, M, Peters, NS, Efimov, IR

المصدر: 999 ; 988

مصطلحات موضوعية: MultiPulse Therapy, atrial fibrillation, cardioversion, defibrillation, 1102 Cardiorespiratory Medicine and Haematology, 1103 Clinical Sciences

جغرافية الموضوع: United States

الوصف: OBJECTIVES: This first-in-human feasibility study was undertaken to translate the novel low-voltage MultiPulse Therapy (MPT) (Cardialen, Inc., Minneapolis, Minnesota), which was previously been shown to be effective in preclinical studies in terminating atrial fibrillation (AF), into clinical use. BACKGROUND: Current treatment options for AF, the most common arrhythmia in clinical practice, have limited success. Previous attempts at treating AF by using implantable devices have been limited by the painful nature of high-voltage shocks. METHODS: Forty-two patients undergoing AF ablation were recruited at 6 investigational centers worldwide. Before ablation, electrode catheters were placed in the coronary sinus, right and/or left atrium, for recording and stimulation. After the induction of AF, MPT, which consists of up to a 3-stage sequence of far- and near-field stimulation pulses of varied amplitude, duration, and interpulse timing, was delivered via temporary intracardiac leads. MPT parameters and delivery methods were iteratively optimized. RESULTS: In the 14 patients from the efficacy phase, MPT terminated 37 of 52 (71%) of AF episodes, with the lowest median energy of 0.36 J (interquartile range [IQR]: 0.14 to 1.21 J) and voltage of 42.5 V (IQR: 25 to 75 V). Overall, 38% of AF terminations occurred within 2 seconds of MPT delivery (p < 0.0001). Shorter time between AF induction and MPT predicted success of MPT in terminating AF (p < 0.001). CONCLUSIONS: MPT effectively terminated AF at voltages and energies known to be well tolerated or painless in some patients. Our results support further studies of the concept of implanted devices for early AF conversion to reduce AF burden, symptoms, and progression.

العلاقة: JACC: Clinical Electrophysiology; http://hdl.handle.net/10044/1/91406Test

الإتاحة: https://doi.org/10.1016Test/j.jacep.2020.12.014
http://hdl.handle.net/10044/1/91406Test

المؤلفون: Hajnys, J., Pagac, M., Mesicek, J., Petru, J., Spalek, F.

المصدر: Advances in Materials Science ; volume 20, issue 1, page 5-15 ; ISSN 2083-4799

الوصف: 3D metal printing is an increasingly popular production of steel parts. The most widespread and most accurate method is SLM (Selective Laser Melting), which uses metallic powder as the input material. The article is dedicated to researching the supplied powder from Renishaw. The powder is made by gas atomization and 3 phases of powder (virgin, sift and waste) that are present in the SLM process are examined. Powder morphology by SEM electron microscopy is investigated and the porosity of the powder is measured by optical method. Next, the powder grain size fraction is examined. In conclusion, there are recommendations and other directions of possible research. The main quantitative result from research is that, in general, small particles are reduced in the sift powder and the number of larger particles is increased, but the powder is still usable for further use.

الإتاحة: https://doi.org/10.2478/adms-2020-0001Test
https://content.sciendo.com/view/journals/adms/20/1/article-p5.xmlTest

المؤلفون: Mudroch, M, Keller, J, Janotka, M, Dujka, L, Petru, J, Sediva, L, Moucka, P, Vymazal, J, Neuzil, P

المصدر: European Heart Journal ; volume 39, issue suppl_1 ; ISSN 0195-668X 1522-9645

مصطلحات موضوعية: Cardiology and Cardiovascular Medicine

الإتاحة: https://doi.org/10.1093/eurheartj/ehy563.p3691Test
http://academic.oup.com/eurheartj/article-pdf/39/suppl_1/ehy563.P3691/25570642/ehy563.p3691.pdfTest

المؤلفون: Janotka, M, Skoda, J, Sediva, L, Petru, J, Chovanec, M, Cerny, S, Skalsky, I, Neuzil, P

المصدر: European Heart Journal ; volume 39, issue suppl_1 ; ISSN 0195-668X 1522-9645

مصطلحات موضوعية: Cardiology and Cardiovascular Medicine

الإتاحة: https://doi.org/10.1093/eurheartj/ehy563.p3828Test
http://academic.oup.com/eurheartj/article-pdf/39/suppl_1/ehy563.P3828/25574206/ehy563.p3828.pdfTest

المؤلفون: Hala, P, Lekesova, V, Mraz, T, Prokopova, M, Petru, J, Sediva, L, Skoda, J, Janotka, M, Chovanec, M, Molnarova, K, Neuzil, P

المصدر: European Heart Journal ; volume 39, issue suppl_1 ; ISSN 0195-668X 1522-9645

مصطلحات موضوعية: Cardiology and Cardiovascular Medicine

الإتاحة: https://doi.org/10.1093/eurheartj/ehy566.p5141Test
http://academic.oup.com/eurheartj/article-pdf/39/suppl_1/ehy566.P5141/25576577/ehy566.p5141.pdfTest

المؤلفون: Michalski, J, Till, J, Petrů, J, Rusz, S, Hilšer, O, Vontorová, J

المصدر: IOP Conference Series: Materials Science and Engineering ; volume 461, page 012053 ; ISSN 1757-899X

الإتاحة: https://doi.org/10.1088/1757-899x/461/1/012053Test
http://stacks.iop.org/1757-899X/461/i=1/a=012053/pdfTest
http://stacks.iop.org/1757-899X/461/i=1/a=012053?key=crossref.902b016312ff4aff548963774a004af2Test

المؤلفون: Švec, J, Szkandera, P, Rusz, S, Hilšer, O, Petru, J

المصدر: IOP Conference Series: Materials Science and Engineering ; volume 461, page 012073 ; ISSN 1757-899X

الإتاحة: https://doi.org/10.1088/1757-899x/461/1/012073Test
http://stacks.iop.org/1757-899X/461/i=1/a=012073/pdfTest
http://stacks.iop.org/1757-899X/461/i=1/a=012073?key=crossref.e07bbd82ea32eaf7188bafa37f7d6314Test