The anticorrosive properties of cerium based conversion coatings deposited on AA6061-T6 alloy by immersion in tmbuffercd cerium chloride and cerium nitrate solutions in the presence of hydrogen peroxide were investiga...The anticorrosive properties of cerium based conversion coatings deposited on AA6061-T6 alloy by immersion in tmbuffercd cerium chloride and cerium nitrate solutions in the presence of hydrogen peroxide were investigated and characterized by potentiodynamic po- larization （PDP） and electrochemical impedance spectroscopy （EIS） in 0.5 mol/L NaCl aqueous solution. The microstructure and chemical composition of the protective films were examined by scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDS）. It was found that the best corrosion protection was afforded by the samples treated during 600 s in cerium chloride solution at pH values ~5.5-4, showing higher amounts of cerium and polarization resistance values greater than 10 f~ m2. Moreover, an ennoblement of the corro- sion potential and decreasing of the cathodic and anodic currents were obtained compared with the cerium nitrate solutions application. This behavior was attributed to the influence of the deposition parameters such as type of the salt anion, i.e., chelating effect and chaotropic characteristics, pH fluctuations in the conversion solution and deposition time.展开更多
Doped and undoped TiCh nanoparticles were prepared by Stober method and thermally treated at 600 ℃.The effect of Nd^（3＋） ion on the structure and micro structure of anatase-phase TiCh nanocrystals was studied by R...Doped and undoped TiCh nanoparticles were prepared by Stober method and thermally treated at 600 ℃.The effect of Nd^（3＋） ion on the structure and micro structure of anatase-phase TiCh nanocrystals was studied by Rietveld refinement method using X-ray powder diffraction data.Bond lengths,bond angles,and edges distances were analyzed.The phase formation was confirmed by high-resolution transmission electron microscopy.The adjustment of Ti-0 bond length induced by the addition of Nd^（3＋） ions,reduced the octahedral distortion and altered the octahedral array in the anatase-phase TiCh nanocrystal.The changes of structure and microstructure were mainly observed for TiCh nanoparticles doped with 0.1 at.%of Nd^（3＋） ions and attributed to the cationic substitution of Ti^（4＋） ions which promoted changes in the density of states and gap band of TiCh.The dopant insertion resulted in a better structural stability of the nanocrystals that enhanced their charge transference and photocatalytic efficiency.展开更多
The Colorado River Delta has undergone a fast and drastic modification by human activities.Since 1930’s decade,agriculture plays a very important role in the development of the region changing land & water use in...The Colorado River Delta has undergone a fast and drastic modification by human activities.Since 1930’s decade,agriculture plays a very important role in the development of the region changing land & water use in Mexicali and Imperial Valleys,politically divided by the Mexico-U.S.A.border but united by the same hydrographic basin,together continue展开更多
Cu-Ni-Al alloys at different concentrations were obtained using a high frequency induction melting unit, keeping a balance in the nominal compositions. Light alloys are important to be used in industrial applications....Cu-Ni-Al alloys at different concentrations were obtained using a high frequency induction melting unit, keeping a balance in the nominal compositions. Light alloys are important to be used in industrial applications. Aluminum additions result in a positive hardness increment of the ternary alloys in comparison with the binary Cu-Ni alloys. Generalized wear mechanisms of the alloys with low aluminum content are basically type abrasive, while samples with 5 and 10 at.% Al present an oxidative-adhesive wear mechanism. Wear results have indicated that aluminum addition affects positively the wear resistance, mainly in samples with high aluminum content product of the creation during the test of different oxides corresponding to the elements present in the alloys.展开更多
Classification method is a formula, logical description generalizing characteristics of objects of related area. Nowadays, billions of smart objects are immersed in the environment, sensing, interacting, and cooperati...Classification method is a formula, logical description generalizing characteristics of objects of related area. Nowadays, billions of smart objects are immersed in the environment, sensing, interacting, and cooperating with each other to enable efficient services. When we think about IoT, classification is a major challenge particularly if our technology is international level applicable. So, this limitation needs clear and deep analysis of the existing classification matrixes and gives some future directions depending on the different researches in the area. The paper surveys the current state-of-art in the classification of IoT. First, we try to explain commonly existing classification matrixes;Second, cooperation of different methods defending on classification matrixes used. Then analyses challenges that IoT faced from classification angle and finally we give some direction for future IoT classification.展开更多
For many years, intermetallic materials promise applications in a wide variety of technology areas. NiAl intermetallic compound is material that exhibits important characteristics such as high corrosion resistance and...For many years, intermetallic materials promise applications in a wide variety of technology areas. NiAl intermetallic compound is material that exhibits important characteristics such as high corrosion resistance and low density besides its ability to retain strength and stiffness at elevated temperatures. However NiAl intermetallic is too hard, brittle and exhibits very low ductility at room temperature being the reason because this material is not yet available for structural applications. In order to increase the ductility of the NiAl intermetallic compound, the addition of a third alloying element has been proved, nevertheless it is important to determine if such additions decrease or increase the hardness and the corrosion resistance of the alloy. So, the present investigation reports the corrosion performance of the NiAl intermetallic compound modified with Cu, emphasizing the EIS analysis and the relation between physical parameters and the modelling equations used in the Equivalent Electric Circuit. It was found that the addition of Cu promotes the formation of the γ’-Ni<sub>3</sub>Al phase in Cu contents greater than 15 at. %, in addition to a decrease in micro hardness and an increment in the I<sub>corr</sub> values. In this way, the electrochemical characterization evidenced a high corrosion resistance of these intermetallic alloys.展开更多
The aim of this study was to evaluate the effect of a hydrogymnastics training program on highsensitivity C-reactive protein in elderly women. The subjects were randomly divided into the experimental group who partici...The aim of this study was to evaluate the effect of a hydrogymnastics training program on highsensitivity C-reactive protein in elderly women. The subjects were randomly divided into the experimental group who participates in the hydrogymnastics training program and the control group who was not involved in the training and remained sedentary. The serum levels of highsensitivity C-reactive protein were determined by immunoturbidimetry using C-reactive protein (CRP), the training protocol consisted of hydrogymnastics sessions 5 times per week during 12 weeks of intervention, executed in a pool of 1.3 meters divided into three phases: a 10-minute warm-up, 30 minutes of aerobic exercise at 50%-60% of maximum heart rate (monitored by heart rate monitor) and a 10-minute cool down. As a statistical method to compare the results between groups of variables pre and post training, the analysis of variance (ANOVA) mixed 2 × 2 (group × measurement) test was done using SPSS version 17. The founds showed significant changes in the level of high-sensitivity C-reactive protein, and a greater percentage decrease of hs-CRP (Δ%= -37%, p = 0.001) in the experimental group in relation to the control group.Therefore, it can be inferred that a hydrogymnastics program is effective in reducing the metabolic rate of high-sensitivity C-reactive protein amongst elderly women.展开更多
Background: Internal carotid artery (ICA) dissections generally occur when a tear occurs in the intima-media layer, either of traumatic or spontaneous origin. In this scenario, multifocal cerebral thrombosis may be a ...Background: Internal carotid artery (ICA) dissections generally occur when a tear occurs in the intima-media layer, either of traumatic or spontaneous origin. In this scenario, multifocal cerebral thrombosis may be a clear consequence of untreated ICA dissection. The incidence of internal carotid artery dissection in the US is estimated to be 1.72 per 100,000 population per year. Objective: To make a brief review of the literature and to explain, through a clinical case, the scenario of multiple ischemic cerebrovascular events is associated with the dissection of the internal carotid artery, in a young patient with no relevant history. Presentation of the Case: A 46-year-old female patient, with no significant history, who came to the emergency service presenting loss of strength in the right pelvic limb, disordered language, and difficulty walking for 3 hours, in the neurological examination evidence of decreased tendon reflexes and loss of strength of the right side of the body. Imaging studies show compromise of the M2 and M3 segments of the left middle cerebral artery, as well as multiple areas of associated ischemia in this hemisphere. Additional studies identify concomitant left ICA dissection. Based on the findings, it was decided to perform a thrombectomy of the affected area, as well as subsequent placement of a stent in the area of dissection. In the control angioTC study, revascularization of the M2 and M3 segments was observed, and in the follow-up of the patient, complete recovery of the symptoms was observed, with muscle strength, tendon reflexes, and preserved language functions. Conclusions: The ischemic cerebrovascular event is a frequent pathological entity in the emergency service;in the scenario of a young patient as mentioned above, it is important to take into consideration the different causes of this pathology. We are obliged to familiarize ourselves with the different imaging modalities for an adequate diagnostic approach, as well as the treatment methods according to the time of evolution.展开更多
基金supported by National Research Network of the National Council for Science and Technology of Mexico (228198)
文摘The anticorrosive properties of cerium based conversion coatings deposited on AA6061-T6 alloy by immersion in tmbuffercd cerium chloride and cerium nitrate solutions in the presence of hydrogen peroxide were investigated and characterized by potentiodynamic po- larization （PDP） and electrochemical impedance spectroscopy （EIS） in 0.5 mol/L NaCl aqueous solution. The microstructure and chemical composition of the protective films were examined by scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDS）. It was found that the best corrosion protection was afforded by the samples treated during 600 s in cerium chloride solution at pH values ~5.5-4, showing higher amounts of cerium and polarization resistance values greater than 10 f~ m2. Moreover, an ennoblement of the corro- sion potential and decreasing of the cathodic and anodic currents were obtained compared with the cerium nitrate solutions application. This behavior was attributed to the influence of the deposition parameters such as type of the salt anion, i.e., chelating effect and chaotropic characteristics, pH fluctuations in the conversion solution and deposition time.
基金supported by Consejo Nacional de Ciencia yTecnologia or National Council of Science and Technology(CONACYT,175925)
文摘Doped and undoped TiCh nanoparticles were prepared by Stober method and thermally treated at 600 ℃.The effect of Nd^（3＋） ion on the structure and micro structure of anatase-phase TiCh nanocrystals was studied by Rietveld refinement method using X-ray powder diffraction data.Bond lengths,bond angles,and edges distances were analyzed.The phase formation was confirmed by high-resolution transmission electron microscopy.The adjustment of Ti-0 bond length induced by the addition of Nd^（3＋） ions,reduced the octahedral distortion and altered the octahedral array in the anatase-phase TiCh nanocrystal.The changes of structure and microstructure were mainly observed for TiCh nanoparticles doped with 0.1 at.%of Nd^（3＋） ions and attributed to the cationic substitution of Ti^（4＋） ions which promoted changes in the density of states and gap band of TiCh.The dopant insertion resulted in a better structural stability of the nanocrystals that enhanced their charge transference and photocatalytic efficiency.
文摘The Colorado River Delta has undergone a fast and drastic modification by human activities.Since 1930’s decade,agriculture plays a very important role in the development of the region changing land & water use in Mexicali and Imperial Valleys,politically divided by the Mexico-U.S.A.border but united by the same hydrographic basin,together continue
文摘Cu-Ni-Al alloys at different concentrations were obtained using a high frequency induction melting unit, keeping a balance in the nominal compositions. Light alloys are important to be used in industrial applications. Aluminum additions result in a positive hardness increment of the ternary alloys in comparison with the binary Cu-Ni alloys. Generalized wear mechanisms of the alloys with low aluminum content are basically type abrasive, while samples with 5 and 10 at.% Al present an oxidative-adhesive wear mechanism. Wear results have indicated that aluminum addition affects positively the wear resistance, mainly in samples with high aluminum content product of the creation during the test of different oxides corresponding to the elements present in the alloys.
文摘Classification method is a formula, logical description generalizing characteristics of objects of related area. Nowadays, billions of smart objects are immersed in the environment, sensing, interacting, and cooperating with each other to enable efficient services. When we think about IoT, classification is a major challenge particularly if our technology is international level applicable. So, this limitation needs clear and deep analysis of the existing classification matrixes and gives some future directions depending on the different researches in the area. The paper surveys the current state-of-art in the classification of IoT. First, we try to explain commonly existing classification matrixes;Second, cooperation of different methods defending on classification matrixes used. Then analyses challenges that IoT faced from classification angle and finally we give some direction for future IoT classification.
文摘For many years, intermetallic materials promise applications in a wide variety of technology areas. NiAl intermetallic compound is material that exhibits important characteristics such as high corrosion resistance and low density besides its ability to retain strength and stiffness at elevated temperatures. However NiAl intermetallic is too hard, brittle and exhibits very low ductility at room temperature being the reason because this material is not yet available for structural applications. In order to increase the ductility of the NiAl intermetallic compound, the addition of a third alloying element has been proved, nevertheless it is important to determine if such additions decrease or increase the hardness and the corrosion resistance of the alloy. So, the present investigation reports the corrosion performance of the NiAl intermetallic compound modified with Cu, emphasizing the EIS analysis and the relation between physical parameters and the modelling equations used in the Equivalent Electric Circuit. It was found that the addition of Cu promotes the formation of the γ’-Ni<sub>3</sub>Al phase in Cu contents greater than 15 at. %, in addition to a decrease in micro hardness and an increment in the I<sub>corr</sub> values. In this way, the electrochemical characterization evidenced a high corrosion resistance of these intermetallic alloys.
文摘The aim of this study was to evaluate the effect of a hydrogymnastics training program on highsensitivity C-reactive protein in elderly women. The subjects were randomly divided into the experimental group who participates in the hydrogymnastics training program and the control group who was not involved in the training and remained sedentary. The serum levels of highsensitivity C-reactive protein were determined by immunoturbidimetry using C-reactive protein (CRP), the training protocol consisted of hydrogymnastics sessions 5 times per week during 12 weeks of intervention, executed in a pool of 1.3 meters divided into three phases: a 10-minute warm-up, 30 minutes of aerobic exercise at 50%-60% of maximum heart rate (monitored by heart rate monitor) and a 10-minute cool down. As a statistical method to compare the results between groups of variables pre and post training, the analysis of variance (ANOVA) mixed 2 × 2 (group × measurement) test was done using SPSS version 17. The founds showed significant changes in the level of high-sensitivity C-reactive protein, and a greater percentage decrease of hs-CRP (Δ%= -37%, p = 0.001) in the experimental group in relation to the control group.Therefore, it can be inferred that a hydrogymnastics program is effective in reducing the metabolic rate of high-sensitivity C-reactive protein amongst elderly women.
文摘Background: Internal carotid artery (ICA) dissections generally occur when a tear occurs in the intima-media layer, either of traumatic or spontaneous origin. In this scenario, multifocal cerebral thrombosis may be a clear consequence of untreated ICA dissection. The incidence of internal carotid artery dissection in the US is estimated to be 1.72 per 100,000 population per year. Objective: To make a brief review of the literature and to explain, through a clinical case, the scenario of multiple ischemic cerebrovascular events is associated with the dissection of the internal carotid artery, in a young patient with no relevant history. Presentation of the Case: A 46-year-old female patient, with no significant history, who came to the emergency service presenting loss of strength in the right pelvic limb, disordered language, and difficulty walking for 3 hours, in the neurological examination evidence of decreased tendon reflexes and loss of strength of the right side of the body. Imaging studies show compromise of the M2 and M3 segments of the left middle cerebral artery, as well as multiple areas of associated ischemia in this hemisphere. Additional studies identify concomitant left ICA dissection. Based on the findings, it was decided to perform a thrombectomy of the affected area, as well as subsequent placement of a stent in the area of dissection. In the control angioTC study, revascularization of the M2 and M3 segments was observed, and in the follow-up of the patient, complete recovery of the symptoms was observed, with muscle strength, tendon reflexes, and preserved language functions. Conclusions: The ischemic cerebrovascular event is a frequent pathological entity in the emergency service;in the scenario of a young patient as mentioned above, it is important to take into consideration the different causes of this pathology. We are obliged to familiarize ourselves with the different imaging modalities for an adequate diagnostic approach, as well as the treatment methods according to the time of evolution.
