Effect of cooling rate during solidification on the hard phases of M23C6-type of cast CoCrMo alloy

Microstructural morphology of CoCrMo alloy by control of the cooling rate during the solidification was investigated. Samples were obtained using both an induction furnace for slow cooling rate and electric arc furnace for fast cooling rate. Microstructural characterizations were performed with metallographic techniques. It was found that the difference between the formation temperature of hard secondary phases of M23C6-type carbides determine the reduction of carbide size by increasing the cooling rate

Governance for Sustainability in an Organization in Central Mexico

Often, the total quality has been instrumented before being weighted. The strategies even precede a diagnosis in Mexican organizations, but in an opposite sense, the present work set out to establish the reliability and validity of an instrument to measure the perception of total quality based on three indicators related to management. , production and transfer of knowledge. A nonperimental study was carried out with a non-probabilistic selection of 124 administrative staff and employees from an organization in central Mexico. From a structural model ⌠X2 = 123,24 (23df) p = 0,010; GFI = 0,990; CFI =,991; IFI = 0,993; RMSEA = 0,007⌡, it was found that management affects production (0,38) and this about the total perceived quality (0,35), although there are lines of research concerning empathy, commitment, entrepreneurship, satisfaction and happiness in relation to the implementation of continuous improvements to the quality of processes and products

Effect of Modified Pin Profile and Process Parameters on the Friction Stir Welding of Aluminum Alloy 6061-T6

This work deals with the effect of a new “bolt-head” pin profile on the friction stir welding performance of the aluminum alloy 6061-T6, compared to traditional pin profiles. Friction stir welding parameters such as the tool rotation speed and the welding speed were investigated together with the different pin profiles; the results show that the new “bolt-head” pin profile leads to better mechanical properties of welded specimens. The pin profiles used in this work were the straight square (SS), straight hexagon (SH), taper cylindrical (TC), and the straight hexagon “bolt-head” (SHBH). It was found that the last pin profile improves the material flow behavior and the uniform distribution of plastic deformation and reduces the formation of macroscopic defects on the welded zone. Mechanical tensile tests on welded specimens were performed to determine the tensile strength: the specimens welded with the SHBH pin profile have shown the highest mechanical properties. An approach is presented for material flow on this aluminum alloy using the SHBH pin profile, which is related to the improvement on the resulting mechanical properties

Photon Shielding Features of Quarry Tuff

Abstract. Cantera is a quarry tuff widely used in the building industry; in this work the shielding features of cantera were determined. The shielding characteristics were calculated using XCOM and MCNP5 codes for 0.03, 0.07, 0.1, 0.3, 0.662, 1, 2, and 3 MeV photons. With XCOM the mass interaction coefficients, and the total mass attenuation coefficients, were calculated. With the MCNP5 code a transmission experiment was modelled using a point-like source located 42 cm apart from a point-like detector. Between the source and the detector, cantera pieces with different thickness, ranging from 0 to 40 cm were included. The collided and uncollided photon fluence, the Kerma in air and the Ambient dose equivalent were estimated. With the uncollided fluence the linear attenuation coefficients were determined and compared with those calculated with XCOM. The linear attenuation coefficient for 0.662 MeV photons was compared with the coefficient measured with a NaI(Tl)-based �-ray spectrometer and a 137Cs source

Climatic variables that favor the Black Sigatoka (Mycosphaerella fijiensis Morelet) [anamorph: Pseudocercospora fijiensis (Morelet) Deighton] infestation in a banana-growing zone

Objective:  Characterize how favorable or unfavorable are the climatic conditions for the incidence and development of Black Sigatoka in the banana región of Teapa, Tabasco, Mexico. Design/Methodology/Approach: Daily temperature data from 59 years from Teapa, Tabasco, Mexico, climatological station (27044) were analized (1961-2019), using historical reports fron IMTA, (2009) and the National Meteorological Service. Relative humidity was estimated using the equation reported by Allen et al. (2006). To determine how suitable are the weather conditions for the incidence and develpment of Black Sigatoka in Teapa, a climatic favorability classification proposed by Júnior et al. (2008) was used. Results: The results shows that in the area under this study, there are no highly favorable climatic conditions for the incidence and development of this disease, and the spring-summer months are the less favorable; while the autum-winter months are the most favorable. Study limitations/implications: It is important to do this kind of studies in other banana producing areas in Tabasco, because the climatic conditions (temperature and relative humidity) they are different, so the disease frequency or appearance may vary. Findings/conclusions: The time period from october to march are the most favorable months for Black Sigatoka incidence and development; so integrated management programs should be designed for this period. Keywords: temperature, relative humidity, banana, yields, probability, prediction models.Objective: To establish the favorable or unfavorable climatic conditions for the emergence and developmentof Black Sigatoka in a banana-growing area within the influence zone of the Teapa weather station (27004) inTabasco, Mexico.Design/Methodology/Approach: We analyzed temperature data for n=59 years (1961-2019) at the Teapaweather station (27044) in Tabasco, as reported by IMTA (2009) and the Servicio Meteorológico Nacional(until 2019). Relative humidity was calculated using the equation developed by Allen et al. (2006). We alsoestablished the favorable or unfavorable climatic conditions for the development of Black Sigatoka in Teapa byresorting to the favorability typology posited by Júnior et al. (2008).Results: There are no highly favorable climatic conditions for the incidence and development of this disease.Overall, spring and summer are the less favorable months, while fall and winter offer more favorable conditions.Study Limitations/Implications: This study should be replicated in other banana-growing areas of Tabasco,since both temperature and relative humidity may differ and, consequently, the frequency of the disease mayvary.Findings/Conclusions: October and March are the most favorable months for Black Sigatoka occurrence.Therefore, comprehensive management and control programs should be designed for this perio

2030 agenda and its considerations in the framework of artisanal fishing cooperatives in Mexico

Objective: Analyze the objectives proposed by the UN, linking them in a theoretical and practical way with the real situation of artisanal fishing cooperativism in Mexico, opposing the theoretical scope of the 2030 Agenda vs. the real praxis of artisanal fishing communities. Design/methodology/approach: Through the application of a Participatory Rapid Assessment Workshop, the points of the 2030 Agenda were discussed with three artisanal fishing communities in Mexico. The participants got to know in a theoretical way the objectives presented by the UN, they selected those that, in their opinion, are an important and punctual part of their fishing activity, to later analyze these objectives and compare them with their practical reality.   Results: Conclusions, proposals and points were obtained by the social subjects recognizing as a general argument that for the Mexican artisanal fishing cooperativism the objectives of the 2030 Agenda are possible as long as the action strategy promotes a cooperative culture with community values ??and social bond, respect for their environment and way of life, as well as the sustainability of the sea as an object of work. Limitations of the study/implications: The main implication was the enormous importance that exists in bringing the theoretical considerations of international organizations and decision makers to the social base where these proposals operate. , since these spaces create discussions that allow the necessary theoretical-practical analysis in the social sciences. Finding/conclusions: The neoliberal global economic system is the main disagreement of the 2030 Agenda. The Agenda encourages developed countries to support underdeveloped countries with knowledge, technology and investments to achieve sustainability, but it does not recognize local knowledge, uses and customs of developing countries as an effective alternative.Objective: To analyze the objectives proposed by the UN, linking them in a theoretical and practical way with the real condition of artisanal fishing cooperatives in Mexico, contrasting the theoretical scope of the 2030 Agenda vs. the real praxis of the communities of artisanal fishermen. Design / Methodology / Approach: Through the application of a Participatory Rapid Appraisal Workshop (PRAW) points of the Agenda 2030 were discussed with three artisanal fishing communities in Mexico. The participants learned in a theoretical way the objectives presented by the UN; selected those that in their opinion are important and punctual parts of their fishing activity; and then analyzed these objectives comparing them with their practical daily reality. Results: Conclusions and clarifications were obtained from the social subjects in which it was recognized as a general argument that for the Mexican artisanal fishing cooperatives framework the objectives of the 2030 Agenda are possible as long as the action strategy promotes a cooperative culture with community values and social bonds; respect for their environment and way of life; as well as the sustainability of the ocean as their means of work. Limitations / Implications of the study: the main implication noticed was the enormous importance that exists towards delivering theoretical considerations from international organizations and decision makers, to the social base who operates these proposals. These spaces create discussions that allow the theoretical analysis of practical needs which is mandatory in the social sciences. Findings / Conclusions: The neoliberal globalized economic system is the main disagreement for the 2030 Agenda. The 2030 Agenda encourages developed countries to support under-developed countries with knowledge, technology and investments to achieve sustainability. However, the Agenda does not recognize local knowledge, use forms and customs in those developing countries, as effective operational alternatives

Pregerminative treatments in Tillandsia ionantha seeds to obtain seedlings under in vitro culture

Objective: To search for an in vitro strategy to favor both germination and a greater number of seedlings in Tillandsia ionantha; also, to promote the development of future research on this species. Design/methodology/approach: Factor one: lighting conditions (light-dark), factor two: 13 preconditioning treatments, which included storage at room temperature and in refrigeration at 10° C, soaking (12 and 24 hours), with hydrogen peroxide (10 and 20 %), potassium nitrate (0.2 and 0.4 %), gibberellins (50 and 150 ml.l-1), three alternate incubation temperatures (28, 32 and 36 °C). They were sown in MS medium (Murashige and Skoog, 1962) at 25 %, adding 20 g.l-1 of sugar, 2 g.l-1 of activated carbon, and 5 .5 g.l-1 of agar. A flask with three seeds which coma removed was established as an experimental unit; 15 repetitions were established and placed in the incubation room at 24 °C with a photoperiod of 16:8. The germination process was recorded, and the seedlings were extracted two months after their establishment. Results: The treatment that resulted in the highest number of seeds that initiated the germination process and the highest number of plants was when the seeds were kept at room temperature. The highest contamination was observed in the treatment exposed to 32 °C. It was observed that 80% of the experimental units showed signs of imbibition within a few days, although the vast majority did not complete the process and the maximum yield was on average 1.4 seedlings. Conclusions: The best treatment is to use seeds stored at room temperature and if storage is necessary, to soak them for 12 h