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17 Uppsatser om Cracking - Sida 1 av 2

Pulveregenskapers inverkan på grönkropp med avseende på sprickor

This thesis is a survey and also an investigation of the different factors that affects the Cracking that occurs in the inserts at AB Sandvik Coromants production in Gimo. The work that has been done has focused on two main factors, namely, powder characteristics and pressing parameters.AB Sandvik Coromant produces tools and tooling systems for metal cutting. They have some problems in their production of inserts. The problem is that cracks sometimes occur in the body of the insert, after it´s pressed. In order to investigate this, a preliminary study was made in which production principles were studied.

Inverkan av tvång i gjutfogar och i betongkonstruktioner på
elastiskt underlag: Influence of Restraint in Casting Joints
and in Concrete Structures on Resilient Foundation

In this report, the risk of Cracking in joints and/in adjacent concrete is estimated by checking shear forces in joints and the ratio between the actual maximum principal stress ant the actual strength of the concrete. The shear force has been estimated both by simple methods as well as by two-dimensional calculations. The risk of Cracking in the concrete and/or in the joints is estimated with the computer program ConStre. The restraint from a resilient foundation or rock on a young concrete construction is estimated by a simple method that is exemplified. It is shown that the restraint can be neglected in some cases.

Nedbrytning av vägar: Jämförelse mellan axlar med singel- respektive tvillingmontage

When designing roads it?s important to knowwhat loads will bedriven on it. The axles on heavy vehicles can either have super single tires ordual tires which, according to studies, damage the roads differently. The SwedishTransport Administration is developing an understanding for the character ofthese different kinds of axle and tire types on the loads induced on Swedishroads. In this thesis a field study was conducted to determine the distributionbetween axles with super single tires and axles with dual tires on heavy vehicles.A highway, a country road and a national road were investigated during thestudy.

Temperatursprickor i ung betong : Utvärdering av projektering och utförande av åtgärder, samt utveckling av dimensioneringsmetod för kylsystem

The report contains three parts. The first part is a summary and overall presentation of thermalcracks and preventing measures against such cracks. This is a theoretical part where theinterested designer can get acquainted with various alternatives, be guided to more detailedliterature, and receive some practical information regarding the design of the respectivemeasures.The second part deals with calculation of the risk for thermal cracks and design of water coolingas a limiting measure. Two complementary methods are reviewed for efficient calculation:?the handbook method CraX1(by Lulea University of Technology) is used for quickverification?finite differential analysis in the calculationtool ConTeSt Pro for more precise projectingHere is also presented a development of existing standards through design of the cooling systemby means of the Bernoulli equation.

Axial- och gradientkrympning hos golv på mark enligt Eurokod 2 : Sprickbredders beroende av betongkvalité, tvångseffekter och armeringshalt

AbstractConcrete foundation slabs are usually exposed to unilateral drying during the curing process. The unilateral drying causes an axial shrinkage and a concave curvature of the construction. The curvature results from the fact that the upper part of the slab is drying and shrinking faster than the lower part. This is called gradient shrinkage.A problem occurs when the slab is considered fully restrained by adjoining structural parts. The deformations caused by axial contraction due to the constant part of the shrinkage and the curvature caused by gradient shrinkage of the slab are then prevented by the fact that the slab is fully restrained.

Icke-linjära modelleringsteknikerav förspänd betongkonstruktion : Reaktorinneslutningen på Forsmark 3

A new material model, for the FE-program ADINA, has been verified against twoexperiments. One unreinforced concrete beam and one reinforced concrete beam.The model, DF-concrete, has the possibility to estimate true concrete. However theresults indicate that in order to be sure that the estimations are true, there ought tobe data from the true concrete to verify against.Two FE-models have simulated the behavior of a ring-shaped part of the nuclearcontainment vessel. The results from the first, frictionless, model agree with similarsimulations and hand calculations for high pressures in the containment vessel. Thesimulations of the nuclear containment vessel show Cracking in the concrete after10-11 bars of over pressurization.

Ipv6 : En empirisk studie i hur Ipv6 protokollet har utvecklats de senaste åren.

Internet grows, so it?s Cracking, soon will all IPv4 addresses be allocated and a solution is urgently needed. The new protocol, IPv6 is the solution to this problem. With a size of 128 bits against IPv4s 32 bits gives IPv6 a huge amount of addresses to distribute. The security addition that may be added manually in IPv4 is the standard with the new protocol.

Detektering av krypterade filer

In contemporary encryption the vast amount of text subject to Cracking has brought about the demand for methods distinguish files more likely to be encrypted. The encryption software Truecrypt can encrypt files that are not possible to identify with a file signature. To solve the detection problem, an algorithm sensitive to the absence of structure in the very code of files was developed. The program was written in the programming language EnScript which is built into the forensic software suite EnCase. The essential part of the algorithm therefore deployes the statistic of a chi-square test for deviance from a uniform distribution to distinguish files with contents that appear to be random.

Dimensionering av betongkonstruktioner : En jämförande studie av BBK 04 och Eurokod 2 vid dimensionering av balkar och pelare

Today, we use BKR and BBK 04 when designing concrete structures inSweden, which will, in the near future, be replaced by Eurocode 2. When you are designing buildings, you will use Eurocode 2 Part 1-1 and with this new standard, some new rules and general rules will be necessary to adopt. To examine how BKR and BBK 04 tells apart from Eurocode 2 when designing concrete structures, one beam and one column with often common dimensions, is studied. The beam is designed with consideration of (considerate to) durability at bending moments, shear forces and control of Cracking. The column is designed with consideration of durability at eccentric axial load and bending moments in cross section on account of (due to) geometric imperfections. BBK 04 has gone one step closer to Eurocode 2 than earlier editions and the things that are different, when calculating reinforcement, is how they use the partial factors.

Lingvistisk knäckning av lösenordsfraser

För att minnas långa lösenord är det inte ovanligt att användare rekommenderas att skapa en mening som sedan sätts ihop till ett långt lösenord, en lösenordsfras.Informationsteoretiskt sett är dock ett språk väldigt begränsat och förutsägbart, varför enligt Shannons definition av informationsteori en språkriktig lösenordsfras bör vara relativt lätt att knäcka.Detta arbete riktar in sig på knäckning av språkriktiga lösenordsfraser, dels i syfte att avgöra i vilken grad det är tillrådligt att basera en lösenordspolicy på lösenordsfraser för skydd av data, dels för att allmänt tillgängliga effektiva metoder idag saknas för att knäcka så långa lösenord.Inom arbetet genererades fraser för vidare användning av tillgängliga knäckningsprogram, och språket i fraserna modelleras med hjälp av en Markov-process. I denna process byggs fraserna upp genom att det används antal observerade förekomster av följder av bokstäver eller ord i en källtext, så kallade n-gram, för att avgöra möjliga/troliga nästkommande bokstav/ord i fraserna.Arbetet visar att genom att skapa modeller över språket kan språkriktiga lösenordsfraser knäckas på ett praktiskt användbart sätt jämfört med uttömmande sökning..

MCNP-modell för beräkning av neutrondos och DPA på reaktortanken vid Ringhals 2

In this report an MCNP (Monte Carlo N-Particle) model is described for the reactor vessel at Ringhals 2. The model is validated against the specific activity in neutron dosimeters, extracted in 1977, 1984 and 1994. The validation showed that the calculations of the model are within the requirements of a maximum of 20 percent uncertainty for every neutron dosimeter except one, extracted after the first cycle. The uncertainty of this cycle was mostly due to the operation data rather than to the MCNP model.The model has been used to investigate various questions concerning radiation damage. The reliability of the traditional measure of radiation damage, fast neutron flux (En > 1MeV) has been evaluated.  This has been done by taking the ratio for this and another measure of radiation damage, DPA (Displacement Per Atom), for various positions and layers.

REDOGÖRELSE FÖR SPRICKARMERING FÖR KONSEKVENT DRAGNA BETONGPLATTOR PÅ MARK : Analys av skillnader mellan BBK 04 och Eurokod 2 med tillämpning av svenskt och danskt nationellt annex

In this diploma work the approach of determining the required amount of reinforcement in slabs exposed to pure tension is processed, on behalf of Ramböll Uppsala. It is a well-known problem in the industry that there are uncertainties in the determining of the amount of crack reinforcement, especially for structures exposed to pure tension. Cracking caused during the time of dehydration in concrete slabs is the most common defect according to statistics made by CBI[1], which provides numbers as high as 35 % of all the defects caused on slabs are generated by cracks. Comparisons between Sweden's former national standard BBK 04, Building Regulations for concrete structures due to restrained forces of shrinkage, and the current European standard Eurocode 2 are carried out through theoretical studies and concludes with several examples of calculations. Rigorous calculations of both standards, BBK 04 and Eurocode 2 with application of the national annex in Sweden and Denmark are performed.

Hållbarhetscertifiering av stadsdelar : En studie av BREEAM Communities praktiska tillämpning i svensk stadsbyggnad

In this diploma work the approach of determining the required amount of reinforcement in slabs exposed to pure tension is processed, on behalf of Ramböll Uppsala. It is a well-known problem in the industry that there are uncertainties in the determining of the amount of crack reinforcement, especially for structures exposed to pure tension. Cracking caused during the time of dehydration in concrete slabs is the most common defect according to statistics made by CBI[1], which provides numbers as high as 35 % of all the defects caused on slabs are generated by cracks. Comparisons between Sweden's former national standard BBK 04, Building Regulations for concrete structures due to restrained forces of shrinkage, and the current European standard Eurocode 2 are carried out through theoretical studies and concludes with several examples of calculations. Rigorous calculations of both standards, BBK 04 and Eurocode 2 with application of the national annex in Sweden and Denmark are performed.

Undersökning av bindningsmekanismer vid pressning av metallaminat : Investigation of bondning mechanisms at the pressing of metal laminates

Increased understanding of the mechanisms that operate in conjunction with the welding of metal surfaces may help to improve existing manufacturing processes, and to enable new products and combinations of materials. The purpose of the project has therefore been to acquire a deeper understanding of what is happening in the bond for steel and for the factors that form the basis for a bond to develop between metals in the production of laminates by pressing. The merge has been done by pressing and the surfaces after the experiments have been studied in detail in the scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX) and with interferenceprofilometry in Wyko, to provide a greater understanding of the mechanisms that influence the bonding in the interface between metals. The project was limited to contain the materials Docol 1000, HyTens 1200, Aluminum AA3003 and a commercial steel. The parameters varied in the experiments to study their influence closer are temperature, pressure, heat treatment and pretreatment. This has been implemented by pressing with varying temperature and pressure.

Att konstruera en frack : En kvalitativ studie om studentfrackens upplevda gränser

This explorative study focuses on young, university attending males (22-27 years) and their understanding and pratice of the classic tail coat. It is based on five qvalitatively interpreted interwievs with a total of six participants, and through open questions regarding individuality and identicalness, limits and possibilities and inclusion and exclusion, a masculininty of a less contemporary hue takes shape. These conversations have revealed the tail coats potential of respresenting a male stereotype that can set a foundational and minimal standard for inclusion. Above this layer these males can then manifest and negotiate their masculine position in a homosocial hierarchy which decides the amount of passage, privilieges and confirmation of self- worth received for the wearer. These negotiation is performed by value bearing symbols (such as medallions, cordons and the like) allowed by the wearer and by the actions that systematically ensure that the lines of the tail coat are watched and unbroken.

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