Development of a gamma irradiation loop to evaluate the performance of a EURO-GANEX process

I. Sanchez-García,H. Galan,A. Núnez,J.M. Perlado,J. Cobos 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.5

A new irradiation loop design has been developed, which provides the ability to carry out radiolyticresistance studies of extraction systems simulating process relevant conditions in an easy and simpleway. The step-by-step loop configuration permits an easy modification of settings and has a relative lowvolume requirement. This irradiation loop has been initially set up to test the main EURO-GANEX processsteps: the lanthanide (Ln) and actinide (An) co-extraction followed by the transuranic (TRU) stripping. The performance and changes in the composition have been analyzed during the irradiation experimentby different techniques: gamma spectroscopy and ICP-MS for the extraction and corrosion behavior ofthe full system, and HPLC-MS and Raman spectroscopy to determine the degradation of the organic andaqueous solvents, respectively. The Ln and An co-extraction step and the corrosion that occurred duringthe first irradiation step revealed the favorable expected results according to literature. The effects ofacidity changes occurred during the irradiation process, the presence of stainless corrosion products insolution as well as the new possible degradation compounds have been explored in the An stripping step. The results obtained demonstrate the importance of developing realistic irradiation experiments wheredifferent factors affecting the performance can be easily studied and isolated

Internal maxillary artery (IMax) – middle cerebral artery bypass in a patient with bilateral atherosclerotic carotid occlusion: A technical case report

Javier Degollado-García,Martin R. Casas-Martínez,Bill Roy Ferrufino Mejia,Juan C. Balcázar-Padrón,Héctor A. Rodríguez-Rubio,Edgar Nathal 대한뇌혈관외과학회 2024 Journal of Cerebrovascular and Endovascular Neuros Vol.26 No.1

Since the first description of the possible utilization of the internal maxillary artery for bypass surgery, there are some reports of its use in aneurysm cases; however, there is no information about the possible advantages of this type of bypass for cerebral ischemic disease.We present a 77-year-old man with a history of diabetes, hypertension, systemic atherosclerosis, and two acute myocardial infarctions with left hemiparesis. Imaging studies reported total occlusion of the right internal carotid artery and 75% occlusion on the left side, with an old opercular infarction and repeated transient ischemic attacks in the right middle cerebral artery territory despite medical treatment. After a consensus, we decided to perform a bypass from the internal maxillary artery to the M2 segment of the middle cerebral artery using a radial artery graft. After performing the proximal anastomosis, the calculated graft’s free flow was 216 ml/min. Subsequently, after completing the bypass, the patency was confirmed with fluorescein videoangiography and intraoperative Doppler. Postoperatively, imaging studies showed improvement in the perfusion values and the hemiparesis from 3/5 to 4+/5. The patient was discharged one week after the operation, with a modified Rankin scale of 1, without added deficits.The use of revascularization techniques in steno-occlusive disease indicates a select group of patients that may benefit from this procedure. In addition, internal maxillary artery bypass has provided a safe option for large areas of ischemia that cannot be supplied with a superficial temporal artery - middle cerebral artery bypass.

Vibration control of a time-varying modal-parameter footbridge:study of semi-active implementable strategies

José M. Soria,Ivan M. Díaz,Jaime H. García-Palacios 국제구조공학회 2017 Smart Structures and Systems, An International Jou Vol.20 No.5

This paper explores different vibration control strategies for the cancellation of human-induced vibration on a structure with time-varying modal parameters. The main motivation of this study is a lively urban stress-ribbon footbridge (Pedro Gómez Bosque, Valladolid, Spain) that, after a whole-year monitoring, several natural frequencies within the band of interest (normal paring frequency range) have been tracked. The most perceptible vibration mode of the structure at approximately 1.8 Hz changes up to 20%. In order to find a solution for this real case, this paper takes the annual modal parameter estimates (approx. 14000 estimations) of this mode and designs three control strategies: a) a tuned mass damper (TMD) tuned to the most-repeated modal properties of the aforementioned mode, b) two semi-active TMD strategies, one with an on-off control law for the TMD damping, and other with frequency and damping tuned by updating the damper force. All strategies have been carefully compared considering two structure models: a) only the aforementioned mode and b) all the other tracked modes. The results have been compared considering human-induced vibrations and have helped the authors on making a decision of the most advisable strategy to be practically implemented.

Mechanosynthesis of graphene nanoribbons from waste zinc–carbon batteries

Martínez-González J.,Reyes-Contreras D.,Vigueras-Santiago Enrique,Patiño-Carachure C.,Reyes-Esqueda J. A.,Castrejón-Sánchez V. H.,García-Orozco I. 한국탄소학회 2022 Carbon Letters Vol.32 No.2

The mechanosynthesis route is a physical top–down strategy to produce different nanomaterials. Here, we report the formation of graphene nanoribbons (GNRs) through this route using carbon bars recovered from discarded alkaline batteries as raw material. The mechanosynthesis time (milling time) is shown to have an influence on different features of the GNRs such as their width and edges features. TEM revealed the presence of GNRs with widths of 15.26, 8.8, and 23.55 nm for the milling times of 6, 12, and 18 h, respectively. Additionally, the carbon bars evolved from poorly shaped GNRs for the shortest milling time (6 h) to well-shaped GNRs of oriented sheets forming for the longest milling time. Besides GNRs, graphene sheets (GNS) of different sizes were also observed. The Raman analysis of the 2D bands identified the GNS signal and confirmed the GNRs nature. ID/IG values of 0.21, 0.32, and 0.40 revealed the degree of disorder for each sample. The in-plane sp2 crystallite sizes (La) of graphite decreased to 91, 60, and 48 nm with increasing peeling time. The RBLM band at 288 cm−1 confirmed the formation of the GNRs. Mechanosynthesis is a complex process and the formation of the GNRs is discussed in terms of a mechanical exfoliation, formation of graphene sheets and its fragmentation to reach GNR-like shapes. It is shown that the synthesis of GNRs through the mechanosynthesis route, besides the use of recycled materials, is an alternative for obtaining self-sustaining materials.

Ramberg–Osgood Stress–Strain Analysis of the Effects of Aging Treatment and Welding on IN600 with a Three-Stage Strain Hardening Behavior

Heriberto Granados‑Becerra,Víctor H. López‑Morelos,Alberto Ruiz,Rafael García‑Hernández,Francisco F. Curiel‑López,Martin R. Barajas‑Alvarez 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

The Ramberg–Osgood equation was applied to model the stress–strain behavior of heat-treated and welded specimens ofInconel 600 up to 0.2 and 0.175 mm/mm of strain, respectively. As-received and aged plates of Inconel 600 were gas metalarc welded to simulate repair of a component in operation. Dog bone shape specimens were tensile tested at a cross headspeed of 0.005 s−1 and the deformation was measured with an extensometer with a gage length of 20 mm. Microstructuralobservations were made in the optical and scanning electron microscope. Fitting the experimental data in the plastic regionof stress–strain curves to a novel three slopes Ramberg–Osgood model enabled estimation of the hardening coefficient, n. The value of n varied from 0.07 to 0.3 depending on the metallurgical condition of the specimen. A notorious increase wasobserved in the value of n for samples heat-treated beyond 25 h and in as-welded samples. The results of this work showeda very good correlation between the model and the experimental curves.

Robust GPI Control of a New Parallel Rehabilitation Robot of Lower Extremities

Héctor Azcaray,Andrés Blanco,Carlos García,Manuel Adam,Juan Reyes,Gerardo Guerrero,César Guzmán 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.5

In this paper, we propose a new robot for lower limbs rehabilitation by using a parallel structure. The goal of this robot is not only to produce smooth and precise motions for ankle, knee, and hip, but also to support trajectory tracking. Its parallel configuration was based on the four-bar mechanism in order to have a more stable and robust structure. For the kinematic analysis, the length of one bar was considered variable. For the dynamic analysis, the Euler-Lagrange method was used to define the equations of motion. For the robot control, the robust generalized proportional integral (GPI) controller was proposed to guarantee safe rehabilitation movements. This parallel robot not only showed good results, but also showed various movement possibilities for lower limbs rehabilitation.

A simple approach to solving the kinematics of the 4-UPS/PS (3R1T) parallel manipulator

Jaime Gallardo-Alvarado,Mario A. García-Murillo,Md. Nazrul Islam,Mohammad H. Abedinnasab 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.5

This work reports on the position, velocity and acceleration analyses of a four-degrees-of-freedom parallel manipulator, 4-DoF-PM for brevity, which generates Three-rotation-one-translation (3R1T) motion. Nearly closed-form solutions to solve the forward displacement analysis are easily obtained based on closure equations formulated upon linear combinations of the coordinates of three non-collinear points embedded in the moving platform. Then, the input-output equations of velocity and acceleration of the robot manipulator are systematically established by resorting to the theory of screws. To this end, the Klein form of the Lie algebra se(3) of the Euclidean group SE(3) is systematically applied to the velocity and reduced acceleration state in screw form of the moving platform cancelling the passive joint rates of the parallel manipulator. Numerical examples, which are confirmed by means of commercially available software, are provided to show the application of the method.

Dual-steel Portal Frame Design to Withstand a Fire Exposure of 45 Minutes

H. García,M. V. Biezma,J. Cuadrado,M. Zubizarreta 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.3

This paper presents the design of industrial portal frames with plain carbon steel (S275) and micro-alloyed Fire Resistant (FR) steel, coated with intumescent paint as fire protection for the structure. The coating improves the overall heat resistance of the metallic structure. The portal frames with different spans were calculated to observe their fire behavior. The structure was dimensioned by estimating the stresses to which each particular structural section was subjected and by selecting the most economic combination. The process was then repeated with the new dimensions to reach an optimal structural design. The key variables analyzed in this study are: five different spans, seven intumescent paint thicknesses, and eleven price ratios between the FR and the S275 steels, considering a fire exposure time of 45 minutes in all of the scenarios under study. The main conclusion was that the use of FR combined with S275 and the intumescent paint system was the most profitable option. In many cases, the better performance of this combination offered the most technically feasible option for the design of portal frame steel structures.

Kinematics of the 4-RUU parallel manipulator generator of the Schönflies motion by means of screw theory

Jaime Gallardo-Alvarado,Mario A. García-Murillo,Md. Nazrul Islam,Mohammad H. Abedinnasab 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.10

This work deals with the inverse–forward kinematic analysis of a symmetric parallel manipulator equipped with a rotary actuator generator of three independent translations and one rotation motion. The closure equations of the displacement analysis are easily formulated based on the unknown coordinates of two points embedded in the moving platform. The input–output equations of velocity and acceleration of the robot are systematically obtained through the reciprocal-screw theory. The pseudo-kinematic pairs that connect the limbs to the fixed platform and a passive kinematic chain connected to the robot manipulator eliminate the handling of rank-deficient Jacobian matrices, which is an undisputable advantage from the computational point of view. Furthermore, this strategy allows the use of the Lie algebra se(3) without the inherent restrictions associated with the limited mobility of the robot.

Effect of Acicular Ferrite and Bainite in API X70 Steel Obtained After Applying a Heat Treatment on Corrosion and Cracking Behaviour

L. R. Jacobo,R. García‑Hernández,V. H. López‑Morelos,A. Contreras 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10

The effect of acicular ferrite (AF) and bainite (B) obtained by heat treatment (HT) applied to an API X70 steel on corrosionresistance and stress corrosion cracking (SCC) susceptibility was evaluated through polarization curves and slow strain ratetests respectively, in NS4 solution and congenital water (CW). The HT was carried out at 1050 °C for 15 and 30 min followedby water quenching. Change of ferrite–perlite to AF and B was observed as result of heat treatment applied to X70steel. Effect of HT time in terms of microstructure obtained was analysed. The mechanical properties obtained by the HTare higher than X100 steel. HT-30 min improve the corrosion resistance of X70 steel exposed to both solutions, which arerelated to coarse and homogeneous microstructure of AF and B. Localized corrosion was observed in the steel exposed toboth solutions. HT-15 min improve mechanical properties and higher content of fine AF, but decreases SCC resistance. Steel with higher content of fine AF microstructure is more susceptible to SCC. SCC indexes revealed that the heat-treatedsteel could be susceptible to SCC in CW confirmed by the secondary cracks observed. The SCC mechanism was hydrogenembrittlement. Meanwhile, steel HT by 15 min exposed to NS4 solution could be susceptible to SCC. Crack growth rate washigher in steel HT by 15 min, which are related to more fine and brittle AF microstructure.