Distribution of contact loads over the flank-land of the cutter with a rounded cutting edge

In this paper, contact conditions between a tool and a workpiece material for wear-simulating turning by a cutter with a sharp-cornered edge and with a rounded cutting edge are analysed. The results of the experimental study of specific contact load distribution over the artificial flank wear-land of the cutter in free orthogonal turning of the disk from titanium alloy (Ti[6]Al[2]Mo[2]Cr), ductile (63Cu) and brittle (57Cu1Al[3]Mn) brasses are described. Investigations were carried out by the method of 'split cutter' and by the method of the artificial flank-land of variable width. The experiments with a variable feed rate and a cutting speed show that in titanium alloy machining with a sharp-cornered cutting edge the highest normal contact load ([sigma][h max]=3400...2200 MPa) is observed immediately at the cutting edge, and the curve has a horizontal region with the length of 0.2... 0.6 mm. At a distance from the cutting edge, the value of specific normal contact load is dramatically reduced to 1100...500 MPa. The character of normal contact load for a rounded cutting edge is different -it is uniform, and its value is approximately 2 times smaller compared to machining with a sharp-cornered cutting edge. In author's opinion it is connected with generation of a seizure zone in a chip formation region and explains the capacity of highly worn-out cutting tools for titanium alloys machining. The paper analyses the distribution of tangential contact loads over the flank land, which pattern differs considerably for machining with a sharp-cornered edge and with a rounded cutting edg

Burnishing tool actuators and their influence on the burnishing force components

The article presents the results of studies on measuring components of force of diamond burnishing of surfaces with variable radius of curvature. The impact of structural elements of burnishing tools of different types on components of burnishing force was analyzed. The impact of different actuators of burnishing tools on components of burnishing force was analyzed. The design of the burnishing tool with an air receiver (bellows with compressed air as an actuator) with a parallelogram-type mounting of the indenter on the four flat posts, which ensures burnishing of profiled and other types of surfaces with constant radial force, was proposed

Using AI/expert system technology to automate planning and replanning for the HST servicing missions

This paper describes a knowledge-based system that has been developed to automate planning and scheduling for the Hubble Space Telescope (HST) Servicing Missions. This new system is the Servicing Mission Planning and Replanning Tool (SM/PART). SM/PART has been delivered to the HST Flight Operations Team (FOT) at Goddard Space Flight Center (GSFC) where it is being used to build integrated time lines and command plans to control the activities of the HST, Shuttle, Crew and ground systems for the next HST Servicing Mission. SM/PART reuses and extends AI/expert system technology from Interactive Experimenter Planning System (IEPS) systems to build or rebuild time lines and command plans more rapidly than was possible for previous missions where they were built manually. This capability provides an important safety factor for the HST, Shuttle and Crew in case unexpected events occur during the mission

Influence of thick-walled cylinders length on the residual stresses generated during the single-cycle mandrelling

The paper presents methodology and results of experimental study by Sachs method the effect of length of mandrelled thick-walled cylinders made of steel grade 50 (0.5% C) with 5 mm diameter hole, outer diameter of 15 and 25 mm on residual stresses. Based on the review of studies, it was noted that this effect may be both due to uneven process of mandrelling along the cylinder length and due to zero axial residual stresses on its faces. It was found that the length of cylinders has the strongest influence on axial residual stresses. With allowances between 0.9 and 7.1% and length reduction from 40 to 10 mm, the largest absolute value of axial residual stresses decreases from 210 to 50 MPa. It was noted that when the outer diameter of cylinders is 15 mm their length significantly influence on both hoop and radial residual stresses. With the above-mentioned decrease in cylinders length, absolute values of hoop and radial residual stresses in the region adjacent to the hole, depending on the mandrelling allowance, increase (from -135 to -205 MPa and from -45 to 55 MPa respectively, when allowance is 7.1%), decrease (from -315 to -235 MPa and from -135 to -95 MPa respectively, when allowance is 0.9%) and remain almost unchanged (when allowance is 3.4%). Impact of length on these stresses is weak when the outer diameter of cylinders is 25 mm

Conducta antisocial - delictiva en estudiantes de secundaria de una institución educativa privada del Callao

La presente investigación tiene como objetivo describir la conducta antisocial y delictiva de los estudiantes de secundaria de una institución educativa privada ubicada en la provincia constitucional del Callao, para lograr dicho objetivo se evaluó a 205 estudiantes de secundaria entre hombres y mujeres, cuyas edades fluctuaban entre 13 a 17 años. Como instrumento se utilizó el Cuestionario de Conductas Antisociales – Delictivas de Seisdedos (1988) adaptada por Pérez (2017) y una ficha sociodemográfica. Los resultados indicaron la existencia de conductas antisociales (64,2%) y delictivas (57, 8%) en un nivel medio, así mismo, se encontraron diferencias significativas entre las conductas antisociales y el sexo, siendo los varones los que presentan mayor porcentaje de conductas antisociales, sin embargo, no se encontraron diferencias significativas entre las conductas delictivas y el sexo. Finalmente, no se encontraron diferencias significativas entre las conductas antisociales y delictivas según edad, año de estudio y tipo de familia

Feasibility of the Davidenkov method for investigation of hoop residual stresses in cold expanded cylinders

Cold expansion of holes in hollow cylinders is accompanied by raise of residual stresses in the bulk of the cylinder, the largest of which are hoop residual stresses. Since hoop residual stresses affect critical performance characteristics, assessment of their nature and magnitude is one of the most significant engineering tasks. The most wide spread mechanical methods to define magnitude of hoop residual stresses are G Sachs and N N Davidenkov methods. The paper presents result of experimental studies by Sachs and Davidenkov methods of hoop residual stresses generated in hollow cylinders made of carbon steel AISI 1050 after cold expansion. It is shown that the shape of curves of hoop residual stresses calculated by the mentioned methods, depending on the hoop residual strain generated on the outer surface of the cylinder, can differ (strain is elastic) or coincide (strain is elastic-plastic). It was established that the absolute values of the stresses defined by the mentioned methods in the area adjacent to the hole differ by an average of 15%, and in the area adjacent to the outer surface differ by an average of 20%

Seguridad y salud ocupacional para la prevención de accidentes laborales en la Bardon Ingenieria S.A.C. - Huaraz, 2022

objetivo: Conocer la seguridad y salud ocupacional y su relación con la prevención de accidentes laborales en los trabajadores de la empresa Bardon Ingeniería S.A.C. - Huaraz, 2022. Metodología: El método científico del tipo de investigación utilizado fue básico, denominado puro o fundamental, el nivel de investigación fue descriptivo - correlacional. Hipótesis: La seguridad y salud ocupacional se relaciona con la prevención de accidentes laborales en los trabajadores de la empresa Bardon Ingeniería S.A.C. - Huaraz, 2022. Las técnicas de recolección de datos utilizadas en este trabajo fueron: Análisis documental, observación y encuesta. Los instrumentos que se aplicaron fueron: Guía de observación, cuestionario, e incluso se hizo uso de registros bibliográficos, investigaciones hemerográficas. Finalmente para la estadística se utilizó el paquete estadístico SPlSS25.0 para la investigación y se tiene en cuenta la interpretación de datos, tablas y figuras estadísticas una vez que se tiene un resultado de conexiones de Spealrman que arroja un valor de 0.601 en la hipótesis general, lo cual es una buena asociación, y finalmente se llega a la conclusión general: La seguridad y l salud ocupacional se relaciona con ella prevención de accidentes laborales en los trabajadores de la empresa Bardon Ingeniería S.A.C. - Huaraz, 2022

Software reuse in spacecraft planning and scheduling systems

The use of a software toolkit and development methodology that supports software reuse is described. The toolkit includes source-code-level library modules and stand-alone tools which support such tasks as data reformatting and report generation, simple relational database applications, user interfaces, tactical planning, strategic planning and documentation. The current toolkit is written in C and supports applications that run on IBM-PC's under DOS and UNlX-based workstations under OpenLook and Motif. The toolkit is fully integrated for building scheduling systems that reuse AI knowledge base technology. A typical scheduling scenario and three examples of applications that utilize the reuse toolkit will be briefly described. In addition to the tools themselves, a description of the software evolution and reuse methodology that was used is presented

Planeamiento estratégico para la región La Libertad

La Región La Libertad ha experimentado en los últimos años un gran desarrollo en la industria del turismo, logrando posicionarse como el tercer lugar más visitado en el Perú por los turistas nacionales y extranjeros (Banco Central de Reserva del Perú [BCRP], 2013). Cabe mencionar que, si bien ocupa este puesto, aún se encuentra muy distante de Lima y Cusco quienes lideran el ranking en cuanto a la acogida de turistas. Asimismo, la Región La Libertad ha mantenido un gran crecimiento en la producción y comercialización de arándanos, siendo de aproximadamente un 200% de variación porcentual en relación a los años anteriores (“Arándanos en Perú”, 2017). Hay un amplio mercado aún por explotar en mercados internacionales en los que se puede incrementar la demanda, gracias a las fortalezas de la región tanto en tierras, clima, entre otros. En cuanto a la producción y comercialización de paltas, la Libertad es el principal productor del país aportando un gran porcentaje del total de la producción que se exporta. La región tiene proyectado incrementar en cuatro veces la producción, en vista que se puede ampliar la cantidad de hectáreas para la cosecha. El presente Plan Estratégico va dirigido al Gobernador Regional Luis Alberto Valdez Farías y busca alcanzar la visión trazada; ser una región referente en el Índice de Competitividad, administrando sus recursos con miras a obtener beneficio para el desarrollo económico y social para la Región, esto se cumplirá a través de la contribución económica de los productos agroindustriales; palta y arándano; y de servicios; turismo al año 2027 (Gobierno Regional de La Libertad, 2017a). Este crecimiento económico para la Región traerá consigo una mejora calidad de vida de los pobladores.La Libertad Region has experienced in recent years a great development in the tourism industry, positioning itself as the third most visited place in Peru by domestic and foreign tourists (Banco Central de Reserva del Perú [BCRP], 2013)., it is worth mentioning that although it occupies this position it is very distant Lima and Cuzco, who lead the ranking in welcoming tourists. Likewise, La Libertad Region has maintained a great growth in the production and commercialization of Blueberries, approximately 200% percentage variation in relation to the previous years (“Arandanos en Perú”, 2017). There is a large market yet to be exploited in international markets where demand can be met, thanks to the strengths in land, climate, among others. Regarding the production and commercialization of avocados, Libertad is the main producer of the country contributing 33% of the total production that is exported. The region has projected to increase production fourfold, given that the amount of hectares can be expanded for the harvest. This Strategic Plan seeks to achieve the vision outlined; be a reference region in the Competitiveness Index, managing its resources with a view to obtaining benefits for economic and social development for the Region, this will be fulfilled through the economic contribution of agro-industrial products; avocado and blueberry; and of services; tourism to the year 2027 (Regional Government of La Libertad, 2017a). This economic growth for the Region will bring an improvement in the quality of life of the inhabitants.Tesi