Статті в журналах: "GMAC"

1

Sameer Sadeq, Abdulrahman, Rosilah Hassan, Azana Hafizah Mohd Aman, Hasimi Sallehudin, Khalid Allehaibi, Nasser Albogami, and Anton Satria Prabuwono. "MAC protocol with grouping awareness GMAC for large scale Internet-of-Things network." PeerJ Computer Science 7 (November 22, 2021): e733. http://dx.doi.org/10.7717/peerj-cs.733.

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The development of Medium Access Control (MAC) protocols for Internet of Things should consider various aspects such as energy saving, scalability for a wide number of nodes, and grouping awareness. Although numerous protocols consider these aspects in the limited view of handling the medium access, the proposed Grouping MAC (GMAC) exploits prior knowledge of geographic node distribution in the environment and their priority levels. Such awareness enables GMAC to significantly reduce the number of collisions and prolong the network lifetime. GMAC is developed on the basis of five cycles that manage data transmission between sensors and cluster head and between cluster head and sink. These two stages of communication increase the efficiency of energy consumption for transmitting packets. In addition, GMAC contains slot decomposition and assignment based on node priority, and, therefore, is a grouping-aware protocol. Compared with standard benchmarks IEEE 802.15.4 and industrial automation standard 100.11a and user-defined grouping, GMAC protocols generate a Packet Delivery Ratio (PDR) higher than 90%, whereas the PDR of benchmark is as low as 75% in some scenarios and 30% in others. In addition, the GMAC accomplishes lower end-to-end (e2e) delay than the least e2e delay of IEEE with a difference of 3 s. Regarding energy consumption, the consumed energy is 28.1 W/h for GMAC-IEEE Energy Aware (EA) and GMAC-IEEE, which is less than that for IEEE 802.15.4 (578 W/h) in certain scenarios.

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2

Yuan, Haoheng, and Bin Dai. "A Capacity-Achieving Feedback Scheme of the Gaussian Multiple-Access Channel with Degraded Message Sets." Entropy 23, no. 6 (June 16, 2021): 756. http://dx.doi.org/10.3390/e23060756.

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The classical Schalkwijk–Kailath (SK) scheme for the point-to-point white Gaussian channel with noiseless feedback plays an important role in information theory due to the fact that it is capacity-achieving and the complexity of its encoding–decoding procedure is extremely low. In recent years, it has been shown that an extended SK feedback scheme also achieves the capacity region of the two-user Gaussian multiple-access channel with noiseless feedback (GMAC-NF), where two independent messages are, respectively, encoded by two intended transmitters. However, for the two-user GMAC-NF with degraded message sets (one common message for both users and one private message for an intended user), the capacity-achieving feedback scheme remains open. In this paper, we propose a novel two-step SK-type feedback scheme for the two-user GMAC-NF with degraded message sets and show that this scheme is capacity-achieving.

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3

Pires de Miranda, Marta, M. Carmo Gomes, and H. Rebelo de Andrade. "Seroprevalence of antibodies to poliovirus in individuals living in Portugal, 2002." Eurosurveillance 12, no. 6 (June 1, 2007): 7–8. http://dx.doi.org/10.2807/esm.12.06.00717-en.

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The last case of poliomyelitis in Portugal caused by indigenous wild poliovirus occurred in 1986 and the country was declared polio-free in 2002. High levels of immunity must be maintained to prevent the importation of wild poliovirus. In this study, we determined the immunity against poliomyelitis of the Portuguese population in order to identify possible immunity gaps. A representative sample of 1,133 individuals older than two years residing in mainland Portugal was studied. Logistical difficulties regarding quick sample transportation precluded the Portuguese islands (Madeira and the Azores) from this study. Sera were collected in 2002 from individuals attending health clinics throughout the 18 districts of Portugal. Levels of neutralizing antibodies against poliovirus types 1, 2 and 3 were determined and a titre of >= 1:8 was defined as indicative of protected immunity. Results were expressed in international units. The antibody prevalence and the geometric mean antibody concentration (GMAC) was 91.6% (GMAC: 2.96 IU/ml), 94.2% (GMAC: 5.03 IU/ml) and 75% (GMAC: 0.53 IU/ml) for poliovirus types 1, 2 and 3, respectively. For poliovirus types 1 and 2, antibody prevalence was close to or above 90% in the majority of age groups. For poliovirus type 3, antibody prevalence was below 80% in teenagers and young adults. Our study shows that the Portuguese are well protected against poliovirus types 1 and 2. For poliovirus type 3, the suboptimal antibody levels observed in teenagers and young adults suggest the need for a booster dose to minimise the risk of wild poliovirus importation.

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4

Menkus, Belden. "Dealer uses phony data to defraud GMAC." Computer Fraud & Security Bulletin 1992, no. 7 (July 1992): 5. http://dx.doi.org/10.1016/0142-0496(92)90011-7.

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5

Heijman, Wim. "The MBA labour market: A note on the global perspectives for graduates in 2015." Applied Studies in Agribusiness and Commerce 10, no. 1 (March 31, 2016): 91–93. http://dx.doi.org/10.19041/apstract/2016/1/12.

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What are the labour market perspectives for MBA graduates in 2015? Each year the GMAC carries out a year-end poll to find out the hiring plans of the employers with respect to graduates in business studies. This short notes presents the most important results for MBA graduates.

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6

Varshney, Abhishek, Samit Kumar Ghosh, Sibasankar Padhy, Rajesh Kumar Tripathy, and U. Rajendra Acharya. "Automated Classification of Mental Arithmetic Tasks Using Recurrent Neural Network and Entropy Features Obtained from Multi-Channel EEG Signals." Electronics 10, no. 9 (May 2, 2021): 1079. http://dx.doi.org/10.3390/electronics10091079.

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The automated classification of cognitive workload tasks based on the analysis of multi-channel EEG signals is vital for human–computer interface (HCI) applications. In this paper, we propose a computerized approach for categorizing mental-arithmetic-based cognitive workload tasks using multi-channel electroencephalogram (EEG) signals. The approach evaluates various entropy features, such as the approximation entropy, sample entropy, permutation entropy, dispersion entropy, and slope entropy, from each channel of the EEG signal. These features were fed to various recurrent neural network (RNN) models, such as long-short term memory (LSTM), bidirectional LSTM (BLSTM), and gated recurrent unit (GRU), for the automated classification of mental-arithmetic-based cognitive workload tasks. Two cognitive workload classification strategies (bad mental arithmetic calculation (BMAC) vs. good mental arithmetic calculation (GMAC); and before mental arithmetic calculation (BFMAC) vs. during mental arithmetic calculation (DMAC)) are considered in this work. The approach was evaluated using the publicly available mental arithmetic task-based EEG database. The results reveal that our proposed approach obtained classification accuracy values of 99.81%, 99.43%, and 99.81%, using the LSTM, BLSTM, and GRU-based RNN classifiers, respectively for the BMAC vs. GMAC cognitive workload classification strategy using all entropy features and a 10-fold cross-validation (CV) technique. The slope entropy features combined with each RNN-based model obtained higher classification accuracy compared with other entropy features for the classification of the BMAC vs. GMAC task. We obtained the average classification accuracy values of 99.39%, 99.44%, and 99.63% for the classification of the BFMAC vs. DMAC tasks, using the LSTM, BLSTM, and GRU classifiers with all entropy features and a hold-out CV scheme. Our developed automated mental arithmetic task system is ready to be tested with more databases for real-world applications.

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7

Schuts, Mathijs, Feng Zhu, Faranak Heidarian, and Frits Vaandrager. "Modelling Clock Synchronization in the Chess gMAC WSN Protocol." Electronic Proceedings in Theoretical Computer Science 13 (December 10, 2009): 41–54. http://dx.doi.org/10.4204/eptcs.13.4.

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8

Gotthelf, Pablo, Alejandro Zunino, Cristian Mateos, and Marcelo Campo. "GMAC: An overlay multicast network for mobile agent platforms." Journal of Parallel and Distributed Computing 68, no. 8 (August 2008): 1081–96. http://dx.doi.org/10.1016/j.jpdc.2008.04.002.

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9

Du, Xian, and Sumeet Dua. "Segmentation of Fluorescence Microscopy Cell Images Using Unsupervised Mining." Open Medical Informatics Journal 4, no. 1 (May 28, 2010): 41–49. http://dx.doi.org/10.2174/1874431101004020041.

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The accurate measurement of cell and nuclei contours are critical for the sensitive and specific detection of changes in normal cells in several medical informatics disciplines. Within microscopy, this task is facilitated using fluorescence cell stains, and segmentation is often the first step in such approaches. Due to the complex nature of cell issues and problems inherent to microscopy, unsupervised mining approaches of clustering can be incorporated in the segmentation of cells. In this study, we have developed and evaluated the performance of multiple unsupervised data mining techniques in cell image segmentation. We adapt four distinctive, yet complementary, methods for unsupervised learning, including those based on k-means clustering, EM, Otsu’s threshold, and GMAC. Validation measures are defined, and the performance of the techniques is evaluated both quantitatively and qualitatively using synthetic and recently published real data. Experimental results demonstrate that k-means, Otsu’s threshold, and GMAC perform similarly, and have more precise segmentation results than EM. We report that EM has higher recall values and lower precision results from under-segmentation due to its Gaussian model assumption. We also demonstrate that these methods need spatial information to segment complex real cell images with a high degree of efficacy, as expected in many medical informatics applications.

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10

Křehlík, Štěpán, Michal Novák, and Jana Vyroubalová. "From Automata to Multiautomata via Theory of Hypercompositional Structures." Mathematics 10, no. 1 (December 21, 2021): 1. http://dx.doi.org/10.3390/math10010001.

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In this paper, we study two important problems related to quasi-multiautomata: the complicated nature of verification of the GMAC condition for systems of quasi-multiautomata, and the fact that the nature of quasi-multiautomata has deviated from the original nature of automata as seen by the theory of formal languages. For the former problem, we include several new conditions that simplify the procedure. For the latter problem, we close this gap by presenting a construction of quasi-multiautomata, which corresponds to deterministic automata of the theory of formal languages and is based on the operation of concatenation.

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11

Xiao, Kexin, Bin Xia, Zhiyong Chen, Jinglun Wang, Dageng Chen, and Shaodan Ma. "On Optimizing Multicarrier-Low-Density Codebook for GMAC With Finite Alphabet Inputs." IEEE Communications Letters 21, no. 8 (August 2017): 1811–14. http://dx.doi.org/10.1109/lcomm.2017.2701801.

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12

Zhang, Chuanguang, Xiaodeng Yang, Shijie Wang, Junying Li, Yuezhi Cui, and Tianduo Li. "Interaction Between GMAC-m-CS and Surfactants: Surface Tension and Conductivity Methods." Journal of Dispersion Science and Technology 37, no. 10 (November 19, 2015): 1502–10. http://dx.doi.org/10.1080/01932691.2015.1015543.

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13

Tana, Maria Gabriella, Roberta Sclocco, and Anna Maria Bianchi. "GMAC: A Matlab toolbox for spectral Granger causality analysis of fMRI data." Computers in Biology and Medicine 42, no. 10 (October 2012): 943–56. http://dx.doi.org/10.1016/j.compbiomed.2012.07.003.

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14

Anderson, J. Richard, Cristina Muise, and David Gancarz. "Partial divestitures as an M&A alternative: The case of GMAC." Journal of Corporate Accounting & Finance 21, no. 2 (January 2010): 71–79. http://dx.doi.org/10.1002/jcaf.20565.

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15

Harshan, J., and B. Sundar Rajan. "A Novel Power Allocation Scheme for Two-User GMAC with Finite Input Constellations." IEEE Transactions on Wireless Communications 12, no. 2 (February 2013): 818–27. http://dx.doi.org/10.1109/twc.2012.122212.120324.

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16

Liu, Yulin, Sufang Huang, Haining Wang, Yueliang Hou, Xianzhuan He, Xinwei Zhu, Ting Li, and Xiaolu Liu. "System Verification Scheme Based on an MCU." Journal of Physics: Conference Series 2166, no. 1 (January 1, 2022): 012004. http://dx.doi.org/10.1088/1742-6596/2166/1/012004.

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Abstract In order to systematically verify the common functions of each peripheral of the chip, find out the problems in the process of chip design in time, and avoid mutual interference between the peripherals of the chip, it is very necessary to systematically verify the chip. The MCU involved in this verification scheme has three cores and several peripherals such as UART, SPI, USB, GMAC and DCMI. In this paper, the common functions of the peripherals of the MCU are verified systematically, and the verification methods of each peripheral are described in detail. The software of this scheme is layered and modular, and the verification system realized according to this scheme can be conveniently transplanted to different chips.

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17

Korneev, V. V., and I. E. Tarasov. "VLSI Architecture with a Configurable Pipeline." Programmnaya Ingeneria 11, no. 5 (October 22, 2020): 270–76. http://dx.doi.org/10.17587/prin.11.270-276.

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The analysis carried out in the article shows the possibility of creating a problem-oriented VLSI, fabricated according to the technological standards of 28 nm or less, for at least one family of digital signal processing problems using similar computing nodes in structure. The use of distributed arithmetic allows one to apply a technique based on performing only those multiplication steps for which non-zero digits are set in the corresponding positions of the filter coefficients. Therefore, the performance of 200 nodes executing 2 steps at 1 GHz is equivalent to approximately 80 GMAC/s/mm2 for 16-bit coefficients. The VLSI architecture view opens up the possibility to study the effectiveness of implementing other families of tasks and refine the architectural parameters for their implementation. The proposed functionality of VLSI computing nodes allows them to be used in various fields of technology, which potentially increases the need for the release of such VLSI.

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18

Machedi, Sechaba, Ikechukwu P. Ejidike, Fanyana M. Mtunzi, Vusumzi E. Pakade, and Michael J. Klink. "Chlorinated Phenols Sorption Performance by Macadamia Activated Carbon and Grafted Macadamia Activated Carbon: Characterization, Kinetics, and Thermodynamic studies." Oriental Journal Of Chemistry 35, no. 5 (October 9, 2019): 1469–79. http://dx.doi.org/10.13005/ojc/350501.

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Our environment is filled with chemicals that pollute the air, water, soil and food, the need to find solutions to the pollution problem. In this study, owing to the research niches like waste beneficiation, macadamia nutshell activated carbon (MAC) was investigated for its potential usage as an adsorbent for chlorinated phenols: 3-chlorophenol, 2,4,6-Trichlorophenol, 4-chloro-3-methylphenol, 2,4-Dichlorophenol removal, and its activity compared with grafted macadamia nutshell activated carbon (GMAC). The adsorbent was characterized using FTIR, SEM, and TGA. Parameters like pH, temperature, contact time, concentration and adsorbent were examined. The PFO and PSO kinetic models were employed to investigate the experimental data. The PSO displayed the best fitting for the kinetic studies for MAC adsorption. The kinetics studies confirmed the adsorption system by pseudo-second-order kinetics model. The negative values of ΔG confirmed a spontaneous process, thereby, supporting the physisorption mechanisms of interactions between the chlorinated phenols and the adsorbents

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19

Szalachowski, P., B. Ksiezopolski, and Z. Kotulski. "CMAC, CCM and GCM/GMAC: Advanced modes of operation of symmetric block ciphers in wireless sensor networks." Information Processing Letters 110, no. 7 (March 2010): 247–51. http://dx.doi.org/10.1016/j.ipl.2010.01.004.

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20

Mariño, Jorge E., and Lucila Mojica A. "Metodología para la exploración de gas asociado al carbón (gmac o cbm) en las cuencas carboníferas de Colombia." Ingeniería Investigación y Desarrollo 13, no. 1 (July 1, 2013): 2. http://dx.doi.org/10.19053/1900771x.4038.

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Normalmente se considera que los gases comercializablesestán exclusivamente asociados al petróleo, pero lasinvestigaciones han demostrado que el carbón es una fuentegeneradora considerable de gas metano en grandes volúmenes(CBM). Colombia cuenta con un buen potencial en reservasde carbón, y se espera que contengan suficientes reservas deCBM que puedan comercializarse durante los próximos años.Este artículo presenta las metodologías estandarizadas deCBM utilizadas en el laboratorio de materiales, carbón y gasasociado al carbón de la UPTC, seccional Sogamoso.La minera colombiana ha presentado tradicionalmente el gasmetano (grisú) como un factor de riesgo debido a lasexplosiones ocasionadas por las emisiones de gas en muchasminas ubicadas en las zonas carboníferas de Colombia, peroesas explosiones y accidentes han llevado a algunos aconsiderar el CBM como un recurso energético. Por eseinterés, es que el objetivo principal de esta investigación se hacentrado en adaptar y establecer dichas metodologías yprocedimientos que se deben utilizar para determinar elcontenido de gas metano mediante el uso de equiposcanisters. Estos canisters y sus equipos adicionales se hanadecuado y mejorado en la UPTC por el grupo deInvestigación de Ingeniería Geológica, durante los últimosaños. Las guías se han realizado siguiendo los conocimientosactuales que hay sobre CBM, y se han propuestorecomendaciones adicionales para hacer más confiable elmuestreo y la medición del gas en los diferentes proyectos deexploración de CBM que se están desarrollando actualmente en las diferentes cuencas carboniferas de Colombia.

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21

Nei, Takahito, Shinya Urano, Natsuki Motoi, Jun Takizawa, Chinatsu Kaneko, Hiroko Kanazawa, Ryushi Tazawa, et al. "IgM-type GM-CSF autoantibody is etiologically a bystander but associated with IgG-type autoantibody production in autoimmune pulmonary alveolar proteinosis." American Journal of Physiology-Lung Cellular and Molecular Physiology 302, no. 9 (May 1, 2012): L959—L964. http://dx.doi.org/10.1152/ajplung.00378.2011.

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The granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibody (GMAb) is the causative agent underlying autoimmune pulmonary alveolar proteinosis (aPAP). It consists primarily of the IgG isotype. At present, information on other isotypes of the autoantibody is limited. We detected serum the IgM isotype of GMAb (IgM-GMAb) in more than 80% of patients with aPAP and 22% of healthy subjects, suggesting that a continuous antigen pressure may be present in most patients. Levels of the IgM isotype were weakly correlated with IgG-GMAb levels but not IgA-GMAb, suggesting that its production may be associated with that of IgG-GMAb. The mean binding avidity to GM-CSF of the IgM isotype was 100-fold lower than the IgG-GMAb isotype, whereas the IC50value for neutralizing capacity was 20,000-fold higher than that of IgG-GMAb, indicating that IgM-GMAb is only a very weak neutralizer of GM-CSF. In bronchoalveolar lavage fluid from nine patients, IgG-GMAb was consistently detected, but IgM-GMAb was under the detection limit in most patients, confirming that IgM-GMAb is functionally a bystander in the pathogenesis of aPAP. It rather may be involved in the mechanism for development of IgG-GMAb in vivo.

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22

Borges, Germana Jayme, Luis Fernando Naldi Ruiz, Ana Helena Gonçalves de Alencar, Olavo César Lyra Porto, and Carlos Estrela. "Cone-Beam Computed Tomography as a Diagnostic Method for Determination of Gingival Thickness and Distance between Gingival Margin and Bone Crest." Scientific World Journal 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/142108.

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The objective of the present study was to assess cone-beam computed tomography (CBCT) as a diagnostic method for determination of gingival thickness (GT) and distance between gingival margin and vestibular (GMBC-V) and interproximal bone crests (GMBC-I). GT and GMBC-V were measured in 348 teeth and GMBC-I was measured in 377 tooth regions of 29 patients with gummy smile. GT was assessed using transgingival probing (TP), ultrasound (US), and CBCT, whereas GMBC-V and GMBC-I were assessed by transsurgical clinical evaluation (TCE) and CBCT. Statistical analyses used independentt-test, Pearson’s correlation coefficient, and simple linear regression. Difference was observed for GT: between TP, CBCT, and US considering all teeth; between TP and CBCT and between TP and US in incisors and canines; between TP and US in premolars and first molars. TP presented the highest means for GT. Positive correlation and linear regression were observed between TP and CBCT, TP and US, and CBCT and US. Difference was observed for GMBC-V and GMBC-I using TCE and CBCT, considering all teeth. Correlation and linear regression results were significant for GMBC-V and GMBC-I in incisors, canines, and premolars. CBCT is an effective diagnostic method to visualize and measure GT, GMBC-V, and GMBC-I.

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23

Brodribb, Tim, and Robert S. Hill. "Imbricacy and Stomatal Wax Plugs Reduce Maximum Leaf Conductance in Southern Hemisphere Conifers." Australian Journal of Botany 45, no. 4 (1997): 657. http://dx.doi.org/10.1071/bt96060.

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An examination of the relationship between theoretical maximum leaf conductance as calculated from stomatal dimensions, and measured maximum leaf conductance was undertaken in a group of Southern Hemisphere conifers. The relative effects of stomatal wax plugs, found in most species of conifers in the Southern Hemisphere, and imbricate leaf arrangement were expressed as a percentage inhibition of maximum leaf conductance (gmax) calculated from the ratio of measured gmax to theoretical gmax Because of the similar stomatal dimensions of all species, measured gmax was proportional to stomatal density in plugged and unplugged species, with species without wax plugs producing maximum leaf conductances on average 91% of calculated gmax, while in species with plugged stomata measured gmax was on average only 35% of theoretical gmax. There was no effect produced by imbricacy in itself, but when combined with epistomy, gmax was significantly reduced to about 17% of theoretical gmax. This is clearly illustrated by comparisons of juvenile-adult foliage, and closely related imbricate and non-imbricate species. The adaptational advantages of imbricacy and wax plugs, and the potential for inferring gmax of fossil taxa are discussed.

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24

Hassas, Salima. "GMAL." ACM SIGOIS Bulletin 12, no. 2-3 (November 1991): 129–34. http://dx.doi.org/10.1145/127769.122843.

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25

Calderón, Alejandro J., Leonidas Kosmidis, Carlos F. Nicolás, Francisco J. Cazorla, and Peio Onaindia. "GMAI." ACM Transactions on Embedded Computing Systems 19, no. 5 (November 11, 2020): 1–23. http://dx.doi.org/10.1145/3391896.

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26

YU, JIANG, BO WANG, HONGTAO ZHANG, PENG HE, JICAI FENG, B. WANG YU, QICHEN WANG, and PENG CHEN. "Characteristics of Magnetic Field Assisting Plasma GMAW-P." Welding Journal 99, no. 1 (January 1, 2020): 25s—38s. http://dx.doi.org/10.29391/2020.99.003.

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The droplet transfer and voltage-current characteristics of gas metal arc welding (GMAW) in single-pulsed GMAW (single GMAW-P), plasma pulsed GMAW (plasma GMAW-P), and plasma-GMAW-P with a magnetic field were studied using the synchronous acquisition system of high-speed camera and electric signals. The results showed the plasma arc and magnetic field had a significant effect on the droplet transfer process. The indirect arc of the plasma and gas metal arc emerged in the pulse peak phase causing a shunt phenomenon of the GMAW current. The period of the indirect arc was increased under the action of the magnetic field. In hybrid plasma GMAW-P, when the GMAW current did not exceed 140 A, several pulsed one-drop free transfers occurred and the droplet transfer period decreased with the increase in the plasma welding current; when the GMAW current exceeded 140 A, and the plasma welding current was less than 180 A, spray transfer was formed. The droplet transfer transformed into a projected transfer when the plasma welding current increased to 180 A. In plasma-GMAW-P hybrid welding with a magnetic field, the magnetic field had a slight effect on the transfer period. When the GMAW current did not exceed 140 A, the droplet transfer was mainly repelled transfer. The detaching location was on the right side of the wire when the magnetic field current was less than 3 A. When the magnetic field current exceeded 3 A, it was below or on the left side of the wire. When the GMAW current exceeded 140 A and the magnetic field current was less than 5 A, spray transfer was formed, but the droplet transfer mode transformed into a projected transfer with a magnetic field current of 5 A.

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27

Zhao, Ji, Yuzong Mu, Yanping Qiao, and Qiang Li. "Newton Recursion Based Random Data-Reusing Generalized Maximum Correntropy Criterion Adaptive Filtering Algorithm." Entropy 24, no. 12 (December 18, 2022): 1845. http://dx.doi.org/10.3390/e24121845.

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For system identification under impulsive-noise environments, the gradient-based generalized maximum correntropy criterion (GB-GMCC) algorithm can achieve a desirable filtering performance. However, the gradient method only uses the information of the first-order derivative, and the corresponding stagnation point of the method can be a maximum point, a minimum point or a saddle point, and thus the gradient method may not always be a good selection. Furthermore, GB-GMCC merely uses the current input signal to update the weight vector; facing the highly correlated input signal, the convergence rate of GB-GMCC will be dramatically damaged. To overcome these problems, based on the Newton recursion method and the data-reusing method, this paper proposes a robust adaptive filtering algorithm, which is called the Newton recursion-based data-reusing GMCC (NR-DR-GMCC). On the one hand, based on the Newton recursion method, NR-DR-GMCC can use the information of the second-order derivative to update the weight vector. On the other hand, by using the data-reusing method, our proposal uses the information of the latest M input vectors to improve the convergence performance of GB-GMCC. In addition, to further enhance the filtering performance of NR-DR-GMCC, a random strategy can be used to extract more information from the past M input vectors, and thus we obtain an enhanced NR-DR-GMCC algorithm, which is called the Newton recursion-based random data-reusing GMCC (NR-RDR-GMCC) algorithm. Compared with existing algorithms, simulation results under system identification and acoustic echo cancellation are conducted and validate that NR-RDR-GMCC can provide a better filtering performance in terms of filtering accuracy and convergence rate.

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28

CHEN, CHAO, CHENGLEI FAN, XIAOYU CAI, ZENG LIU, SANBAO LIN, and CHUNLI YANG. "Characteristics of Arc and Metal Transfer in Pulsed Ultrasonic-Assisted GMAW." Welding Journal 99, no. 7 (July 1, 2020): 203s—208s. http://dx.doi.org/10.29391/2020.99.019.

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Анотація:

Pulsed ultrasonic-assisted gas metal arc welding (PU-GMAW) is a newly developed welding method. Pulsed frequency is one of the most important parameters in the PU-GMAW process. In this paper, the influence of pulsed frequency on the GMAW of aluminum alloy was studied. The results showed that the conventional GMAW process was improved significantly by adding different pulsed frequencies. The pulsed arc length, which was the change of arc length with the change of pulsed frequency, was obtained when the pulsed frequency ranged from 1 to 10 Hz. The stable compression arc length was obtained when the pulsed frequency exceeded 20 Hz. The metal transfer frequency in PU-GMAW in-creased compared to conventional GMAW. The increase of burning arc space pressure in PU-GMAW was mainly the reason for the change of the arc length. The increase in electro-magnetic force and acoustic radiation force was the fundamental reason for the increase in droplet frequency.

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29

Bian, Jiang, Hao Wu, Xing Xiao, Qi Wu, and Zheng-Long Zhou. "Experimental Study on the Gmax Characteristics of the Sand-Silt Mixed Soil Materials Using Bender Element Testing." Materials 15, no. 18 (September 6, 2022): 6200. http://dx.doi.org/10.3390/ma15186200.

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To study the small strain shear modulus (Gmax) of saturated sand-silt mixed soil materials, a series of tests were conducted using the bender element apparatus, and the influences of fines content (FC), relative density (Dr), and effective confining pressure (σ′3c) were taken into consideration. The test results indicate that the Gmax of the mixed soil materials decreases first and then increases with the FC up to 100% with Dr = 35% and 50%, while the Gmax decreases with the increasing FC when Dr = 60%. Moreover, for a given Dr, the Gmax increases with the increasing σ′3c, and the increase rate keeps constant under various FCs. The Gmax of specimens under various FCs decreases with the increase of the void ratio (e). The decrease rate between the Gmax and e differs when the σ′3c is given, which is influenced by the FC. The Gmax of the mixed soil materials can be evaluated by the Hardin model when the FC is determined. The best-fitting parameter A of the Hardin model first decreases and then increases as FC increases. The revised Hardin model, considering the influence of FC, σ′3c, and e, can be used to evaluate the Gmax for different types of sand-silt mixed soil materials. The error between the evaluated and tested Gmax is less than 10%.

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30

Zheng, Sen Mu, and Hong Ming Gao. "Experimental Study on GMAW with Strip Electrode." Advanced Materials Research 314-316 (August 2011): 1025–28. http://dx.doi.org/10.4028/www.scientific.net/amr.314-316.1025.

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Анотація:

GMAW with strip electrode is a new method, which uses the flat wire with a rectangular cross-section to replace the conventional round wire as consumable electrode. In the present study, the welding system was established. Then the typical arc behavior and metal transfer were analyzed. After that, high-speed-high-current welding experiment was carried out in both GMAW with strip electrode and conventional round wire. The results show that, Compared with the conventional GMAW with round wire, the welding arc of GMAW with strip electrode has much lower arc pressure, and the impact of the droplet on the weld pool is weakened remarkably. These two characteristics make GMAW with strip electrode suitable for high efficiency welding on the basis of maintaining the original advantages of GMAW.

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31

RAMOS-MORALES, Francisco, Carmen VIME, Michel BORNENS, Concepción FEDRIANI, and Rosa M. RIOS. "Two splice variants of Golgi-microtubule-associated protein of 210 kDa (GMAP-210) differ in their binding to the cis-Golgi network." Biochemical Journal 357, no. 3 (July 25, 2001): 699–708. http://dx.doi.org/10.1042/bj3570699.

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Анотація:

GMAP-210 (Golgi-microtubule-associated protein of 210kDa) is a peripheral Golgi protein that interacts with the minus end of microtubules through its C-terminus and with cis-Golgi network membranes through its N-terminus; it participates in the maintenance of the structural integrity of the Golgi apparatus [Infante, Ramos-Morales, Fedriani, Bornens and Rios (1999) J. Cell Biol. 145, 83–98]. We report here the cloning of a new isoform of GMAP-210 that lacks amino acid residues 105–196. On the basis of the analysis of the gmap-210 genomic sequence, we propose that the small isoform, GMAP-200, arises from alternative splicing of exon 4 of the primary transcript. Overexpression of GMAP-200 induces perturbations in both the Golgi apparatus and the microtubule network that are similar to those previously reported for GMAP-210 overexpression. We show that both isoforms are able to oligomerize under overexpression conditions. Analysis in vitro and in vivo, with the green fluorescent protein as a marker, reveals that the binding of the N-terminal domain of GMAP-200 to the cis-Golgi network membranes is lower than that of the N-terminal domain of GMAP-210. Implications for the regulation of interaction between the cis-Golgi network and microtubules are discussed.

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32

Nguyen, Cuong M., and V. Chandrasekar. "Gaussian Model Adaptive Processing in Time Domain (GMAP-TD) for Weather Radars." Journal of Atmospheric and Oceanic Technology 30, no. 11 (November 1, 2013): 2571–84. http://dx.doi.org/10.1175/jtech-d-12-00215.1.

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Abstract The Gaussian model adaptive processing in the time domain (GMAP-TD) method for ground clutter suppression and signal spectral moment estimation for weather radars is presented. The technique transforms the clutter component of a weather radar return signal to noise. Additionally, an interpolation procedure has been developed to recover the portion of weather echoes that overlap clutter. It is shown that GMAP-TD improves the performance over the GMAP algorithm that operates in the frequency domain using both signal simulations and experimental observations. Furthermore, GMAP-TD can be directly extended for use with a staggered pulse repetition time (PRT) waveform. A detailed evaluation of GMAP-TD performance and comparison against the GMAP are done using simulated radar data and observations from the Colorado State University–University of Chicago–Illinois State Water Survey (CSU–CHILL) radar using uniform and staggered PRT waveform schemes.

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33

Dierksheide, J., D. Harwig, N. Evans, and L. Kvidahl. "New Automated Tandem Process for Agile Fillet Welding of Ship Structures." Journal of Ship Production 21, no. 02 (May 1, 2005): 81–91. http://dx.doi.org/10.5957/jsp.2005.21.2.81.

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Анотація:

New ship designs are calling for complex, lightweight panels made of thinner steel (as thin as 3 mm) for weight and structure optimization. For stiffener welding on ship panels, thin steel demands small, precision fillet welds in order to reduce panel distortion and improve downstream processes. The existing panel welding systems in most shipyards use flux-cored arc welding with mechanical seam tracking and cannot cope with the complexity and precision required. Tandem gas metal arc welding (T-GMAW) has shown an increase in deposition rate of up to three times that of single-electrode GMAW while offering process robustness. However, when T-GMAW was combined with through-the-arc (TTA) seam tracking by weaving, the travel speed was limited to 1 m/min (40 in./min) and the minimum fillet weld size was 5 mm. Rotating electrode (RE) GMAW utilizes TTA seam tracking by rotating the contact tip and electrode around a small diameter at 10 to 100 Hz. This method results in capabilities to seam track while making welds as small as 2 mm at travel speeds as high as 2.5 m/min (100 in./min). RE-GMAW is also a robust process with enhanced bead shape characteristics ideal for horizontal fillet welds. However, because RE-GMAW is a single-electrode process, it cannot match the deposition rates of T-GMAW. This project developed rotating lead tandem (RLT) GMAW, which is a new process that offers deposition rates comparable to T-GMAW with the seam-tracking capability of RE-GMAW. An objective was to develop the preferred torch setup and electrode conditions that provide a complete range of fillet weld sizes for agile processing of ship structures. Procedures were developed for 3-, 4-, 6-, and 8-mm fillet welds with RLT-GMAW using the ARCWISE (EWI, Columbus, OH) procedure development method on a seam-tracking T-joint test. Process robustness was assessed by evaluating fusion quality, leg size, convexity, process stability, and spatter susceptibility. A preferred torch setup was determined that met the project objective. RLT-GMAW was shown to offer deposition rates that were near or equal to standard tandem GMAW, especially on smaller 3and 4-mm fillets. While offering high deposition rates, it also demonstrated high-resolution seam tracking at travel speeds up of 2.3 m/min on 3-mm fillets.

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34

Devaraj, Jeyaganesh, Aiman Ziout, and Jaber E. Abu Qudeiri. "Dissimilar Non-Ferrous Metal Welding: An Insight on Experimental and Numerical Analysis." Metals 11, no. 9 (September 18, 2021): 1486. http://dx.doi.org/10.3390/met11091486.

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Анотація:

In recent years Gas Metal Arc Welding (GMAW) technology has expanded its functionalities in various areas which have further motivated its usage in several emerging manufacturing industries. There are several issues and challenges associated with this technology, especially in dissimilar metal welding (DMW). One of the predominant challenges is selecting appropriate welding parameters which influence the efficiency of this technology. To explore several modern advancements in this expertise, this paper has done an exclusive survey on various standards of GMAW and its variants for selecting suitable parameters for welding dissimilar nonferrous metals. This review summarizes various experimental and numerical results along with related illustrations to highlight the feasibility of welding dissimilar nonferrous metals using traditional GMAW and investigations on advanced GMAW processes such as cold metal transfer (CMT) and pulsed GMAW (P-GMAW). Simulation and modeling of nonferrous DMW have identified several research gaps and modeling problems. Researchers and manufacturers can use this review as a guideline to choose appropriate welding parameters to implement GMAW and its variants for non-ferrous dissimilar welding. It found that by controlling the heat input and effective post-heat treatments, adequate joint properties can be achieved. Automated large -scale manufacturing will widen the utilization scope of GMAW and avoid some costly methods such as laser welding, ultrasonic welding, and friction stir welding etc.

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35

Kumar, Sudhir, Nikki Archana Barla, Ramkishor Anant, and Kuldeep Kumar Saxena. "A study on shrinkage residual stresses, microstructure and mechanical properties of ASS thick pipe welded by GMAW process." Materials Research Express 8, no. 11 (November 1, 2021): 116504. http://dx.doi.org/10.1088/2053-1591/ac33ff.

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Abstract In this investigation, AISI 304LN austenitic stainless steel pipes having 25 mm thickness and 300 mm inner diameter with conventional and narrow groove were welded by continuous current gas metal arc welding (GMAW) and pulse current gas metal arc welding (P-GMAW) process. A gas tungsten arc welding (GTAW) process was used for the welding of the root pass. Microstructural study was carried out in fusion zone (FZ) and heat-affected zone (HAZ). A favourable microstructure characteristic was observed in the P-GMAW process. The study of transverse shrinkage and shrinkage stresses were done on the conventional groove with GMAW and P-GMAW process and narrow groove by P-GMAW process. It was found that narrow groove weld design with controlled welding parameters can reduce 45% shrinkage as compare to conventional groove, similarly 30% reduction in shrinkage stress can be achieved. The tensile properties were observed to increased, such as yield strength was improved from 260 MPa to 310 MPa and ultimate strength was improved from 510 MPa to 550 MPa in the case of narrow groove weld by the P-GMAW process.

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36

Li, Kehai, and YuMing Zhang. "Metal Transfer in Double-Electrode Gas Metal Arc Welding." Journal of Manufacturing Science and Engineering 129, no. 6 (June 9, 2007): 991–99. http://dx.doi.org/10.1115/1.2769729.

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Gas metal arc welding (GMAW) is the most widely used process for metal joining because of its high productivity and good quality, but analysis shows that the fundamental characteristic restricts conventional GMAW from further increasing the welding productivity. A novel GMAW process, refereed to as double-electrode GMAW or DE-GMAW, thus has been developed to make it possible to increase the melting current while the base metal current can still be controlled at a desired level. This fundamental change provides an effective method to allow manufacturers to use high melting currents to achieve high melting speed and low base metal heat input. A series of experiments have been conducted to uncover the basic characteristics of this novel process. Results obtained from analyses of high-speed image sequences and recorded current signals suggest that DE-GMAW can lower the critical current for achieving the desired spray transfer, shift the droplet trajectory, reduce the diameter of the droplet, and increase the speed and (generation) rate of the droplets.

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37

Wang, Jun, Katalin Tóth, Kiwamu Tanaka, Cuong T. Nguyen, Zhe Yan, Laurent Brechenmacher, Jeremy Dahmen, et al. "A Soybean Acyl Carrier Protein, GmACP, Is Important for Root Nodule Symbiosis." Molecular Plant-Microbe Interactions® 27, no. 5 (May 2014): 415–23. http://dx.doi.org/10.1094/mpmi-09-13-0269-r.

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Legumes (members of family Fabaceae) establish a symbiotic relationship with nitrogen-fixing soil bacteria (rhizobia) to overcome nitrogen source limitation. Single root hair epidermal cells serve as the entry point for bacteria to infect the host root, leading to development of a new organ, the nodule, which the bacteria colonize. In the present study, the putative role of a soybean acyl carrier protein (ACP), GmACP (Glyma18g47950), was examined in nodulation. ACP represent an essential cofactor protein in fatty acid biosynthesis. Phylogenetic analysis of plant ACP protein sequences showed that GmACP was classified in a legume-specific clade. Quantitative reverse-transcription polymerase chain reaction analysis demonstrated that GmACP was expressed in all soybean tissues but showed higher transcript accumulation in nodule tissue. RNA interference-mediated gene silencing of GmACP resulted in a significant reduction in nodule numbers on soybean transgenic roots. Fluorescent protein-labeled GmACP was localized to plastids in planta, the site of de novo fatty acid biosynthesis in plants. Analysis of the fatty acid content of root tissue silenced for GmACP expression, as determined by gas chromatography–mass spectrometry, showed an approximately 22% reduction, specifically in palmitic and stearic acid. Taken together, our data provide evidence that GmACP plays an important role in nodulation.

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38

Nowodworski, Witold. "Gmach Biblioteki." Archiwa, Biblioteki i Muzea Kościelne 23 (March 16, 2020): 53–59. http://dx.doi.org/10.31743/abmk.6830.

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39

Rauch, Isabella, Linda Lundström, Markus Hell, Wolfgang Sperl, and Barbara Kofler. "Galanin Message-Associated Peptide Suppresses Growth and the Budded-to-Hyphal-Form Transition of Candida albicans." Antimicrobial Agents and Chemotherapy 51, no. 11 (August 13, 2007): 4167–70. http://dx.doi.org/10.1128/aac.00166-07.

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ABSTRACT The expression of the mRNA encoding galanin message-associated peptide (GMAP) in human keratinocytes is upregulated by lipopolysaccharides and exposure to Candida albicans. GMAP has growth-inhibiting activity against C. albicans and inhibits the budded-to-hyphal-form transition, establishing GMAP as a possible new component of the innate immune system.

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40

Romero-Orozco, Alan Jadir, José Jaime Taha-Tijerina, Rene De Luna-Alanís, Victor Hugo López-Morelos, María del Carmen Ramírez-López, Melchor Salazar-Martínez, and Francisco Fernando Curiel-López. "Evaluation of Microstructural and Mechanical Behavior of AHSS CP780 Steel Welded by GMAW-Pulsed and GMAW-Pulsed-Brazing Processes." Metals 12, no. 3 (March 21, 2022): 530. http://dx.doi.org/10.3390/met12030530.

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Анотація:

Joints of complex phase 780 (CP-780) advanced high strength steel (AHSS) were carried out by using an ER-CuAl-A2 filler metal for the gas metal arc welding pulsed brazing (GMAW-P- brazing) process and the ER-80S-D2 for the GMAW-P process employing two levels of heat input. The phases in the weld bead and HAZ were analyzed, and the evaporation of zinc by means of scanning electron microscopy (SEM) was also monitored. The mechanical properties of the welded joints were evaluated by tension, microhardness and vertical impact tests. It was found that there was greater surface Zn evaporation in the joints welded with the GMAW-P process as compared to the GMAW-P-brazing process. The best results in tensile strength were observed in the joints welded with GMAW-P-brazing process, which increased by ~68% with respect to those of the GMAW-P. This behavior can be attributed to the formation of an intermetallic complex compound Cu-Al-Fe in the fusion line.

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41

Kurşun, T. "Effect of the Gmaw and the Gmaw-P Welding Processes on Microstructure, Hardness, Tensile and Impact Strength of Aisi 1030 Steel Joints Fabricated by ASP316L Austenitic Stainless Steel Filler Metal." Archives of Metallurgy and Materials 56, no. 4 (December 1, 2011): 955–63. http://dx.doi.org/10.2478/v10172-011-0105-x.

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Effect of the Gmaw and the Gmaw-P Welding Processes on Microstructure, Hardness, Tensile and Impact Strength of Aisi 1030 Steel Joints Fabricated by ASP316L Austenitic Stainless Steel Filler Metal In this study, medium-carbon steel (AISI 1030) plates of 10 mm thickness, were welded by using the synergic controlled pulsed (GMAW-P) and manual gas metal arc (GMAW) welding techniques. Constant wire feed speed, voltage, welding speed and gas flow rates (3.2 m/min, 22.5 V, 4 mm/s, 16 1/min) and ASP316L austenitic stainless steel filler metal were used in these techniques. The interface appearances of the welded samples were examined by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-Ray diffraction (X-RD). In order to determine mechanical properties of samples, the tensile, impact and microhardness tests were conducted. The GMAW-P joints of AISI 1030 steel couples showed superior tensile strength, less grain growth and narrower heat affected zone (HAZ) when compared with GMAW joints, and this was mainly due to lower heat input, fine fusion zone grain and higher fusion hardness.

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42

Surasno, Surasno. "PENINGKATAN KUALITAS SAMBUNGAN LAS PEDAL REM MENGGUNAKAN PROSES GMAW." Jurnal Teknologi Bahan dan Barang Teknik 3, no. 1 (June 30, 2013): 23. http://dx.doi.org/10.37209/jtbbt.v3i1.33.

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Sambungan komponen pedal rem yang dilas menggunakan proses GMAW gas pelindung CO2100% mengandung cacat-cacat las spatter, weld-bead ripple, undercut dan porositas pada batas level 8,2%, dengan mengganti proses GMAW gas campuran pelindung Ar75% CO225%, cacat las berkurang hingga batas level 0,88% didominasi oleh spatters sedangkan cacat-cacat las lainnya hampir tidak ada. Pengamatan khususnya cacat las spatter penggunaan gas pelindung CO2100% menunjukkan pada batas level 2,77%, dengan mengganti proses GMAW gas campuran pelindung Ar 75% CO225% cacat las spatters menurun hingga ke batas level 1,11%, oleh karena itu metoda penggantian gas pelindung pada proses GMAW terjadi perbaikan kualitas sambungan las pedal rem hingga 150%. Hal ini akan berdampak terhadap peningkatan daya saing industri komponen pedal rem kendaraan bermotor roda dua.Kata kunci: pedal rem, spatter, process las GMAW, gas pelindung CO2, gas campuran pelindung Ar75%CO225%

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43

Wu, Qi, Qingrui Lu, Qizhou Guo, Kai Zhao, Pen Chen, and Guoxing Chen. "Experimental Investigation on Small-Strain Stiffness of Marine Silty Sand." Journal of Marine Science and Engineering 8, no. 5 (May 21, 2020): 360. http://dx.doi.org/10.3390/jmse8050360.

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The significance of small-strain stiffness (Gmax) of saturated composite soils are still of great concern in practice, due to the complex influence of fines on soil fabric. This paper presents an experimental investigation conducted through comprehensive bender element tests on Gmax of marine silty sand. Special attention is paid to the influence of initial effective confining pressure ( σ c 0 ′ ), global void ratio (e) and fines content (FC) on Gmax of a marine silty sand. The results indicate that under otherwise similar conditions, Gmax decreases with decreasing e or FC, but decreases with increasing FC. In addition, the reduction rate of Gmax with e increasing is not sensitive to σ c 0 ′ , but obviously sensitive to changes in FC. The equivalent skeleton void ratio (e*) is introduced as an alternative state index for silty sand with various FC, based on the concept of binary packing material. Remarkably, the Hardin model is modified with the new state index e*, allowing unified characterization of Gmax values for silty sand with various FC, e, and σ c 0 ′ . Independent test data for different silty sand published in the literature calibrate the applicability of this proposed model.

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44

Ng, Jonathan Leo, Chris Button, Dave Collins, Susan Giblin, and Gavin Kennedy. "Assessing the Internal Reliability and Construct Validity of the General Movement Competence Assessment for Children." Journal of Motor Learning and Development 8, no. 1 (April 1, 2020): 87–106. http://dx.doi.org/10.1123/jmld.2018-0047.

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Validated assessment tools for movement competence typically involve the isolation and reproduction of specific movement forms, which arguably neglects individuals’ ability to combine and adapt movements to overcome constraints within a dynamic environment. A new movement assessment tool, the General Movement Competence Assessment (GMCA), was developed for this study using Microsoft Kinect. Movement competence of 83 children (36 boys and 47 girls), aged 8–10 years (9.06 ± 0.75 years) was measured using the GMCA. An exploratory approach was undertaken to examine the internal consistency reliability (McDonald’s omega coefficient) and factorial structure of the GMCA for the study sample. Factorial structure was determined using exploratory factor analysis by principal component analysis with varimax rotation. For the sample data, reliability for the GMCA games were acceptable (ω = 0.53–0.89) and indicated that combinations of movement attributes were measured by GMCA games. Factorial analysis extracted four movement constructs accounting for 71.31% of variance. Dexterity was tentatively identified as a new independent construct alongside currently accepted movement constructs (i.e., locomotion, object-control, stability). While further development of the GMCA is still required, initial results are encouraging in view of an objective and theoretically informed approach to assess general movement competence in children.

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45

Taukoor, Vashish, Cassandra J. Rutherford, and Scott M. Olson. "A semi-empirical relationship for the small-strain shear modulus of soft clays." E3S Web of Conferences 92 (2019): 04005. http://dx.doi.org/10.1051/e3sconf/20199204005.

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Анотація:

The small-strain shear modulus (Gmax) is a soil property that has many practical applications. The authors compiled a database of Gmax measurements for 40 normally consolidated to slightly overconsolidated low to high plasticity clays. Using these data, the authors propose a semi-empirical relationship between Gmax, effective stress (σ'v or σ'c), preconsolidation stress (σ'p) and in-situ void ratio (e0) for four ranges of plasticity index (Ip): Ip < 30%, 30% ≤ Ip < 50%, 50% ≤ Ip < 80% and 80% ≤ Ip < 120%. With results from bender element tests on a Gulf of Mexico clay subjected to multiple load-unload consolidation loops, the authors were able to validate the proposed relationships for 30% ≤ Ip < 50% and 50% ≤ Ip < 80%. The proposed relationship for 30% ≤ Ip < 50% and 50% ≤ Ip < 80% captures changes in laboratory Gmax resulting from variations in effective stress (σ'c), maximum past stress (σ'v,max), and void ratio. The proposed relationships are a simple and efficient tool that can provide independent insight on Gmax if the stress history of a clay is known, or on stress history if Gmax is known.

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46

Kang, Gyeong-o., Woong Choi, and Changho Lee. "Prediction of Small-Strain Dynamic Properties on Granulated Spherical Glass Bead-Polyurethane Mixtures." Advances in Civil Engineering 2019 (September 12, 2019): 1–12. http://dx.doi.org/10.1155/2019/6348326.

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This paper aims to propose predictive equations for the small-strain shear modulus (Gmax) and small-strain damping ratio (Dmin) of a granulated mixture with plastic and nonplastic materials to reduce the dynamic energy of the ground. Polyurethane bead (PB) and glass bead (GB) were used as the plastic and nonplastic materials, respectively. 180 resonant-column tests were conducted with various conditions affecting the dynamic properties, such as nonplastic particle content (PC), void ratio (e), particle-size ratio (sr), and mean effective confining pressure (σm′). The results showed that Gmax and Dmin, respectively, increased and decreased as e decreased with increasing σm′ of material mixtures. In addition, Gmax decreased with an increase in PC, whereas Dmin increased. It was also found that sr of materials affected the changes in Gmax and Dmin. With an increase in sr, Gmax increased while Dmin decreased because small particles do not hinder the behavior of large particles as the size of larger particles increases. Finally, based on the results, new equations for estimating Gmax and Dmin of a granulated mixture with PB and GB were proposed as functions of PC, e, median grain size (D50), and σm′.

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TENNI, BOUCHRA, MYRIAM BROCHU, STÉPHANE GODIN, and DENIS THIBAULT. "Shielding Gas and Inclusion Content Effects on Impact Toughness and Tensile Properties of 410NiMo Steel Welds." Welding Journal 100, no. 01 (January 1, 2021): 52–62. http://dx.doi.org/10.29391/2021.100.005.

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The effect of shielding gas on the mechanical and microstructural characteristics of ER410NiMo martensitic stainless steel weldments was investigated. Three weldments with various inclusion contents were manufactured using different shielding gas compositions and welding processes: gas metal arc welding (GMAW) with 100% argon (Ar), GMAW 85% Ar/15% carbon dioxide (CO2), and flux cored arc welding (FCAW) 75% Ar/25% CO2. The inclusions in each weldment were characterized by means of scanning electron microscope observations and energy-dispersive spectroscopy analysis. The weldments underwent postweld heat treatment, after which the chemical composition and reformed austenite proportion were measured to account for microstructural effects. Hardness measurements, tensile tests, and impact toughness tests using the Charpy method were performed. The results showed that the Charpy V-notch (CVN) absorbed energy decreases with increasing inclusion content. The highest CVN absorbed energy, 195 J, was obtained for the GMAW 100% Ar weld, which had the lowest inclusion content. GMAW 85% Ar/15% CO2, with four times more inclusions than the former, had a CVN absorbed energy of 63 J. The current manufacturing process, FCAW 75% Ar/25% CO2, was found to have an inclusion content three times higher than the GMAW 100% Ar weld but a CVN absorbed energy of 66 J, which is close to the GMAW 85% Ar/15% CO2 weld. The results showed that using GMAW 100% Ar as a replacement to FCAW 75% Ar/25 % CO2 would lead to a three-fold improvement in terms of absorbed impact energy. The effect of inclusions on tensile properties, which was not clearly identified as several factors, in addition to inclusion content, affects the weld strength and elongation. Overall, the yield and ultimate tensile strengths differed slightly: 724 and 918 MPa for GMAW 100% Ar, 746 and 927 MPa for GMAW 85% Ar/15% CO2, and 711 and 864 MPa for FCAW 75% Ar/25% CO2, respectively.

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48

Mohammad, Walaa S., and Walaa M. Elsais. "Association Between Hip Rotation and Activation of the Quadriceps and Gluteus Maximus in Male Runners." Orthopaedic Journal of Sports Medicine 8, no. 11 (November 1, 2020): 232596712096280. http://dx.doi.org/10.1177/2325967120962802.

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Background: Although running can provide health benefits, knee joint injuries are frequently reported by recreational runners. To date, the precise mechanism responsible for anterior knee pain remains elusive, and the source of symptoms is debated. Inconsistencies are found in the literature pertaining to the relationship between hip mechanics and activity in the quadriceps and gluteus maximus (GMax) during the running gait. Purpose/Hypothesis: To investigate the correlations between hip rotation and the activity in the quadriceps and GMax during running. We hypothesized that increased hip rotation is correlated with decreased activity in these muscles. Study Design: Descriptive laboratory study. Methods: A cohort of 30 healthy recreational runners volunteered to participate in the study (mean ± SD age, 28.8 ± 5.66 years; height, 1.73 ± 0.05 m; mass, 69 ± 6.3 kg; body mass index, 23.02 ± 1.42 kg/m2). Surface electromyography (EMG) data were obtained from the GMax, vastus medialis obliquus (VMO), and vastus lateralis obliquus (VLO). These data were synchronized with a motion capture system during a level-surface running activity at a speed of 3.2 m/s. Results: A significantly strong, negative correlation was found between the hip internal rotation angle and EMG activity of the GMax and the VMO. However, the VLO showed a significant, moderate, and positive correlation of activity with the hip internal rotation angle. Conclusion: The present study showed that during level-surface running, decreased GMax activity may be the cause of distal joint injuries and alteration in quadriceps muscle activity. Clinical Relevance: Because GMax activity is important for controlling the lower body mechanics during running, evaluating GMax activity and internal hip rotation angle is important to prevent the running-related knee injuries that are linked to quadriceps deficits, such as patellofemoral pain. Additionally, clinicians and trainers should consider strengthening the GMax while rehabilitating running-related knee injuries.

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RIBEIRO, R. A., P. D. C. ASSUNÇÃO, E. B. F. DOS SANTOS, E. M. BRAGA, and A. P. GERLICH. "Globular-to-Spray Transition in Cold Wire Gas Metal Arc Welding." Welding Journal 100, no. 4 (April 1, 2021): 121–31. http://dx.doi.org/10.29391/2021.100.010.

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The electrical current required for a transition from globular to spray droplet transfer during gas metal arc welding (GMAW) is determined by the specified wire feed speed in the case of constant-voltage power supplies. Generally, in narrow groove welding, spray transfer is avoided, be-cause this transfer mode can severely erode the groove sidewalls. This work compared the globular-to-spray transition mechanism in cold wire gas metal arc welding (CW-GMAW) vs. standard GMAW. Synchronized high-speed imaging with current and voltage samplings were used to characterize the arc dynamics for different cold wire mass feed rates. Subsequently, the droplet frequency and diameter were estimated, and the parameters for a globular-to-spray transition were assessed. The results suggest that the transition to spray occurs in CW-GMAW at a lower current than in the standard GMAW process. The reason for this difference appears to be linked to an enhanced magnetic pinch force, which is mainly responsible for metal transfer in higher welding current conditions.

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Kang, Taehoon, Jiyoung YU, Young-Min Kim, Insung Hwang, Seung Hwan Lee, and Dong-Yoon Kim. "Weldability Evaluation of GMAW and GTAW for Al-6.7 wt.% Mg Alloy." Journal of Welding and Joining 39, no. 5 (October 30, 2021): 471–79. http://dx.doi.org/10.5781/jwj.2021.39.5.2.

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In this study, the arc weldability of an aluminum alloy was investigated based on its Mg content. The base materials used in the experiments were aluminum with a Mg content of 6.7 wt.% (referred as Al-6Mg) and commercial Al5083-O. The weldability of two types of fusion welding methods was evaluated: gas metal arc welding (GMAW) and gas tungsten arc welding (GTAW). The tensile strength, hardness, alloy composition, and microstructure properties of the welds of two types of the aluminum alloys were compared. The tensile strength values of the GMAW and GTAW welds of Al-6Mg were 20% and 10% higher than those of Al5083-O, respectively. The weld hardness of the GMAW and GTAW welds of both aluminum alloys were similar. Al-6Mg by GMAW and GTAW were smaller than those of Al5083-O. Based on the results of analysis of the welds, the residual magnesium content was as high as 37% by GMAW and 30% by GTAW.

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