Finite element modeling of straightening of thin-walled seamless tubes of austenitic stainless steel

During this thesis work a coupled thermo-mechanical finite element model (FEM) was builtto simulate hot rolling in the blooming mill at Sandvik Materials Technology (SMT) inSandviken. The blooming mill is the first in a long line of processes that continuously or ingotcast ingots are subjected to before becoming finished products. The aim of this thesis work was twofold. The first was to create a parameterized finiteelement (FE) model of the blooming mill. The commercial FE software package MSCMarc/Mentat was used to create this model and the programing language Python was used toparameterize it. Second, two different pass schedules (A and B) were studied and comparedusing the model. The two pass series were evaluated with focus on their ability to healcentreline porosity, i.e. to close voids in the centre of the ingot. This evaluation was made by studying the hydrostatic stress (σm), the von Mises stress (σeq)and the plastic strain (εp) in the centre of the ingot. From these parameters the stress triaxiality(Tx) and the hydrostatic integration parameter (Gm) were calculated for each pass in bothseries using two different transportation times (30 and 150 s) from the furnace. The relationbetween Gm and an analytical parameter (Δ) was also studied. This parameter is the ratiobetween the mean height of the ingot and the contact length between the rolls and the ingot,which is useful as a rule of thumb to determine the homogeneity or penetration of strain for aspecific pass. The pass series designed with fewer passes (B), many with greater reduction, was shown toachieve better void closure theoretically. It was also shown that a temperature gradient, whichis the result of a longer holding time between the furnace and the blooming mill leads toimproved void closure.

Finite element analysis of hot rolling in the blooming mill

During this thesis work a coupled thermo-mechanical finite element model (FEM) was builtto simulate hot rolling in the blooming mill at Sandvik Materials Technology (SMT) inSandviken. The blooming mill is the first in a long line of processes that continuously or ingotcast ingots are subjected to before becoming finished products. The aim of this thesis work was twofold. The first was to create a parameterized finiteelement (FE) model of the blooming mill. The commercial FE software package MSCMarc/Mentat was used to create this model and the programing language Python was used toparameterize it. Second, two different pass schedules (A and B) were studied and comparedusing the model. The two pass series were evaluated with focus on their ability to healcentreline porosity, i.e. to close voids in the centre of the ingot. This evaluation was made by studying the hydrostatic stress (σm), the von Mises stress (σeq)and the plastic strain (εp) in the centre of the ingot. From these parameters the stress triaxiality(Tx) and the hydrostatic integration parameter (Gm) were calculated for each pass in bothseries using two different transportation times (30 and 150 s) from the furnace. The relationbetween Gm and an analytical parameter (Δ) was also studied. This parameter is the ratiobetween the mean height of the ingot and the contact length between the rolls and the ingot,which is useful as a rule of thumb to determine the homogeneity or penetration of strain for aspecific pass. The pass series designed with fewer passes (B), many with greater reduction, was shown toachieve better void closure theoretically. It was also shown that a temperature gradient, whichis the result of a longer holding time between the furnace and the blooming mill leads toimproved void closure.

Combates entre la memoria y la historia de Chile : Conflictos sobre el pasado reciente

The reestablishment of democracy in Chile has seen an intense debate about the events of the recent past, especially on the issue of human rights. From the very beginning, the Concertacion Government has been determined to discover the truth of the repression carried out by the national security forces with a series of commissions that have gathered the testimonies of victims and their relatives. These efforts have been resisted by conservative sectors linked to the dictatorship and the Armed Forces. There has been intense conflict in the media during the past 20 years about events that occurred during the rule of Salvador Allende and the Military Regime. In this regard, a great diversity of information has been produced which, together with the debate evoked, has enabled historians not only to rigorously and thoroughly reconstruct the operation of the state terror but also to explain how a significant sector of Chile’s civil society allowed that situation. This article presents, on one hand, different methodological tools in order to study the recent past and, on the other hand, the social discussion on how to do it.

Al-Mahdi - Gestalt och budskap : En litteraturstudie jämförande sudanesisk Mahdi och indisk Mahdi inom islam

Followers of three world religions, Judaism, Christianity and Islam are waiting for the Messiah. Muslims are even waiting for aspiritual leader al-Mahdi. Two different persons claimed the title of al-Mahdi, at the end of the nineteenth century. Theyappeared almost at the same time, at the totally different places of the earth, with a completely different message and underthe rule of the British colonial power. The aim of the study is to compare the both religious figures, Mirza Ghulam Ahmadfrom India and Muhammad Ahmad from Sudan regarding their different messages, to illustrate the social, political andreligious factors that lead to the entirely different profile and image of these two men and how their organizations havedeveloped after their death up till today. The result shows that the Sudanese Mahdi Muhammad Ahmad claimed hisMahdiship in the year 1881. He became a political leader in a time when Sudan was under the rule of a colonial power. Hetook advantage of the religion for personal purposes and tried to liberate his native country Sudan. The contemporaryMuslim clergy criticized him for his claim because the content of the Hadith traditions did not support his claim ofMahdiship. He maintained his sole right for the interpretation of religion and of the laws of Sharia. He made changes even inthe chief pillars of Islam by asserting that Jehad with sword was more imperative than the pilgrimage journey to Mecca. Heasserted that the Prophet Muhammad himself had entrusted him to launch the holy war against the non-believers. He hadimmense ambitions which were never fulfilled since he suddenly died four years after his claim for Mahdiship, in June 1885.This day his followers are organized as a political party in Sudan with a modest roll in the Sudanese politics. The IndianMahdi Mirza Ghulam Ahmad claimed in 1889 to be Mahdi, Mujaddid, Muhaddas, Messiah and a Prophet at a time of socialand political peace, though Islam as a religion was firmly pushed by the Hindu and Christian missionaries. He had no politicalambitions at all and was utterly loyal to the British colonial power. His mission was to crush the Cross and to demonstrateIslam’s excellence over all the religions of the world through overwhelming arguments. He proclaimed that Jesus was humanand a Prophet and not the son of God. Jesus survived from the cross and died a natural death after he had lived for manyyears. Ahmad claimed that God had commanded him to put stop to the religious wars. The contemporary Muslim clergyblamed him for being an imposter, melancholic and hypochondriac who had self invented the divine revelations. He died year1908, nineteen years after his claim and the communion he found is established today in more than hundred countries of theworld. Reasons for the breakdown of mission of the Sudanese Mahdi were that his objectives were political and he challengedthe colonial power with the sword. Another decisive factor was his sudden death merely four years after the beginning of hismission. Reasons for the success of Indian Mahdi were that his objectives were purely religious and he was wholly loyal to theforeign government. He survived nineteen years after the beginning of his mission which made it possible for him to create acommunion based on solid grounds. His followers continued on the same path and never engaged in local politics where everthey lived. For further studies it will be of great interest to study the life of Mirza Ghulam Ahmad and objectively examine thearguments he presented in support of his divine appointment. Furthermore it is enriching to study the organization andactivities of the Ahmadiyya Muslim community to explore if they are in accordance with the basic principles of Ahmad.

El sentimiento trágico en San Manuel Bueno, mártir : Una lucha contra la razón en búsqueda de la fe

Este trabajo de investigación tiene como fin analizar el pensamiento del autor Miguel de Unamuno para poder relacionarlo con los pensamientos del personaje del cura de la novela San Manuel Bueno, mártir. El objetivo es buscar la relación que existe entre el autor y el cura en lo que se refiere a los temas relacionados con la religión. Para este estudio se utilizará la metodología hermenéutica donde se analizará el pensamiento del autor en relación con el personaje San Manuel, basándose principalmente en el libro Del sentimiento trágico de la vida, uno de los libros más destacados sobre el pensamiento filosófico del autor. Al final, como una pequeña aportación a la tesis, se hablará de la posible misión profética que tuvo Unamuno en sus últimos años de vida que a través de sus obras quiso despertar la conciencia de sus lectores para que se unieran a la búsqueda de la verdadera fe.

”Tacksamhet för att jag fick ett nytt liv” : En kvalitativ studie om återanpassningsstrategier efter avtjänat fängelsestraff

Intresset för kriminalitet och individerna bakom de kriminella handlingarna ökar i samhället och återges i media dagligen. Det är just individen bakom brottet, hen som fängslas och får avtjäna sitt straff som denna studie riktar sitt fokus på. När fängelsegrindarna öppnas och återinträdet till samhället blir ett faktum; Hur tar då dessa individer sig tillbaka till samhället för att åter bli en del av det? Syftet med denna studie är att undersöka vilka återanpassningsstrategier som frigivna använder sig av samt hur samhällets bemötande påverkar strategierna. Studien baseras på självbiografier skrivna av fyra författare som alla levt ett kriminellt liv och som sedermera avtjänat ett eller flera fängelsestraff. Resultatet visar att det finns flera anpassningsstrategier som tas i bruk. Däribland att söka hjälp och stöd hos familj, vänner eller andra sociala grupper. Vidare återfinns det i strävan efter en ”ny identitet” vilket ofta sker med hjälp av tro. Att sysselsätta sig, ge något tillbaka till samhället, visa sin kreativitet i syfte att återfå sin kredibilitet kan ses som strategier som leder fram till det slutliga målet, kredibiliteten. Slutligen kunde ett samband mellan samhällets bemötande och återanpassningsstrategierna utrönas. Ju mer negativt bemötandet är desto fler återanpassningsstrategier behövs och arbetet för att uppnå dem blir mer krävande. Givet blir då att ett bemötande som fyllts av uppmuntran till individens förändring medför att färre strategier behövs och risken för återfall blir mindre.