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1560 Uppsatser om Strength of materials - Sida 7 av 104
Hur påverkas muskelaktiviteten vid styrketräning med en tjock stång i jämförelse med en standardolympisk stång? : En EMG- studie
Many everyday tasks and also many sports require good grip and forearm strength. Everything from carrying boxes and lifting a child to grab the arms and legs in various martial arts, or holding a tennis racket involving the hand and forearm muscles in various ways. It is therefore important to train these muscles to prevent injuries and congestion and to perform well in sport. A well known way to train functional strength in the hand and forearm muscles is weight training with thick handles. The purpose of this study was to investigate the differences in muscle activity in the upper arm and forearm muscles as well as the deltoids between two bars of different diameter (28mm and 57mm) in two different weight training exercises using electromyography (EMG).
Val av stommaterial : Vilket är det mest fördelaktiga stommaterialet vid uppförande av en hallbyggnad?
When constructing an industrial- or hall building, the most common framework materials thatis used are wood, steel or concrete. Due to an assignment from Byggnadstekniska Byrån ABhas a document been created that makes it possible to investigate how the final costs is af-fected by gapes in between elements and which used foundation. And this with steel as thematerial. The purpose with this essay is to investigate which is the most well fitted materialwhen constructing an industrial- or hall building wood, steel or concrete. Information aboutthe different materials has been collected by litterateurs and by different internet pages.
Värdering av föroreningsrisk - Ett förslag till angreppssätt för värdering av föroreningsrisk till följd av emission från en vägkonstruktion
When constructing a road the risk of emission of substances from the used materials to the surrounding environment has to be evaluated. The aim of this study is to present a proposal for how to evaluate the risk of contamination as a result of emission from the materials in a road construction. The study is based on literature studies, an inventory and a questionnaire that examines how experts in governmental agencies, industries and universities evaluate the risk of contamination. The inventory indicates that guidelines for evaluating the risk of emission from secondary materials in a road construction do not exist. The conclusions from the questionnaire are: that there is no common way to evaluate the risk of contamination as a result of emission from materials in the road construction, there is no uniform interpretation of the terms "minor" and "significant" risk of contamination and that the evaluation is subjective.
Blood compatibility of biomaterials made of recombinant spider silk
Native spider silk is an attractive lightweight natural polymeric material with a unique combination of strength, extendibility and flexibility. Synthetic, recombinant spider silk is an attractive biomaterial with several possible fields of application.
When a foreign material is introduced to blood, this can for example cause unwanted coagulation and complement activation.
The aim of this study was to investigate if coatings of heparin or albumin could improve the blood compatibility of films of recombinant spider silk and to develop an initial method to do so. Hypothetically, objects like pacemakers, stents and dental implants could be covered with spider silk films of high blood compatibility to reduce potentially harmful foreign body reactions caused by the immune defense. Increased blood compatibility would likely lead to improvements for both the individual patients and the society thanks to reduced load on healthcare institutions.
Our objective was to assess the blood compatibility of both functionalized and non-functionalized recombinant spider silk by evaluating coagulation and activation of the complement system of the immune defense.
Coagulation was evaluated visually on glass slides and complement activation was analyzed by measuring the concentration of the complement system mediator C3a in blood samples that had been exposed to the different materials.
This study introduces a non-toxic and easy performed method of improving the blood compatibility of recombinant spider silk films by adding a heparin coating.
Heparin coated surfaces had statistically significantly higher blood compatibility than uncoated surfaces. The effects of albumin coating of films were less clear compared to the results of heparin coated films.
Complement activation could not be evaluated because of high activation in all samples prior contact with the materials that were included in the study..
Betong - Förvånansvärt lättflytande!
Concrete is a very common construction material. It´s characteristics are strength, durability and formablility. Superplasticizer is a common admixture, which changes the properties of concrete.
Today (spring 2007) there are no certian mathematical methods to calculate the required percentage of this admixture needed to give the necessary set slump flow in the overall concrete recipe.
Concrete batching companies must therefor experiment with different amount of superplasticizer in order to meet the specified slump and strength.
The purpose og this report is to investigate if any mathematical relation can be established between the amount of superplasticizer used and the slump flow achieved.
After carrying out some practical experiments using four different superplasticizers a direct relationship can be establish between the percentage of admixture used and the slump/flowability achieved. Unfortunatly at present due to the numerous variables, the calculation of mathematical formula can not be achieved..
Miljövärdering av resurssnål betong med införande i BIM
This thesis aims to illustrate how environmental impact can be reduced, through the use of lean concrete. It also illustrates how environmental data can be applied to a house through implementation with BIM. In this study a unique concrete structure developed by Swedish Cement and Concrete Research Institute is assessed for environmental impact, by calculating the carbon dioxide equivalents using LCA methodology. The construction is a sandwich element where the concrete is made ??up of three layers.
Träning och manuell behandling för att minska impingementliknande symptom i skuldran hos idrottare? : En systematisk litteraturstudie
AimThe purpose of this study is to investigate whether there is scientific evidence that exercise and/or manual therapy can improve function, in terms of increased mobility and strength on shoulder impingement-like symptoms among athletes. Another aim is to investigate whether these interventions can reduce shoulder pain.MethodA systematic review was conducted in the databases PubMed, CINAHL, PEDro and Amed. A total of thirteen articles were selected for further review and compilation. They were then graded for level of evidence according to the PEDro scale and the Swedish Council on Technology Assessment (SBU).ResultsThe systematic review shows that there is strong scientific evidence that acupuncture and heat can reduce pain in athletes diagnosed with supraspinatus-tendiopathy. There is limited scientific evidence that exercise increases strength, limited scientific evidence that stretching increases mobility and insufficient scientific evidence that a combination of treatments, with both exercise and stretching, reduces pain and increases function in overhead athletes.ConclusionsExercise and manual therapy can reduce pain and/or improve function in terms of increased mobility and strength in athletes with shoulder impingement-like symptoms.
Styrketillväxt med hjälp av vibrationsplatta
Abstract 1.The purpose of this study was to investigate the effects whole body vibrations on maximal strength, power output and neuromuscular activity in m. pectoralis major during bench press.Participants consisted of 35 male and 9 female military high school students (m=23, 1 years). On the basis of initial maximal performances in bench press the participants was divided into two experiments groups and one control group. Intervention groups performed a specifically designed push up program on a vibrating plate respectively a step board during 12 weeks Initial load at 60 % of 1 RM showed an average of 46, 5 kg. All groups showed an average increase of 13 kg for each person after 12 weeks.
Ett kandidatexamensarbete inom lättviktskonstruktioner .
Due to recent legal enactments regarding carbon dioxide emissions, the car industry is facing higher demands. An effective way of reducing these emissions is to minimize the weight of the vehicle. This thesis constitutes a feasibility study on whether or not it is applicable for the car industry to utilize an inner floor structure comprising composite materials. The principal was the projectSåNätt, in which the main participant was Volvo Cars Corp. In consultation with a reference group, consisting of delegates from the industry and KTH, a specification of requirements was produced.
ENERGI- OCH KOSTNADSEFFEKTIVAMATERIALVAL I VÄRMESYSTEM : En jämförelse av rörmaterial i vattenburna värmesystem
The thesis aims to compare differentpiping materials in heating systems interms of cost as well as to illustratethe impact of energy characteristics ofdifferent materials over its servicelife. The methods used for costcalculations regarding piping are alsoto be examined to highlight thedifferences between template basedcalculations and more carefully executedones. The work is delimited to discusspipes of steel, copper, plastics andcomposites. The aim is that the resultcan be compiled to illustrate the prosand cons of various materials whenevaluating investments.The main object of the survey is part ofa heating system in the office-block KVSommaren located in southern Stockholm.The configured piping system is designedwith the mentioned piping materials andis used to make up the data for flow andcost calculations. The differentmaterials are calculated in both aconventional manner with a supplementarycost for additional fittings and with amore accurate quantification of thecomponents.
Konstruktion av formkropp pa JAS 39 E/F Gripen
The aim of this work is to develop new conceptual designs for the fairings that are situated between the fin and the rear fuselage on the new version of the JAS 39 Gripen aircraft, called the Gripen E/F. The designs presented should show a profit in the form of lower weight. To achieve weight loss, the possibilities of using other construction materials other than those which are available at Saab today were studied. Therefore, a material survey was carried out in which the market for modern construction materials was studied to get an idea of today?s level of technology.
Påverkan av skogsbrand på litiska arkeologiska fynd ? experimentell simulering av brand
This is a paper about the effects from smoldering fire on lithic objects from an archaeological view.
The introduction gives the background to this paper, a short orientation to forest wildfires and why the work is limited to: flint, quartz, quartzite and slate. Material and methods describes the stone materials and the setup that was used in the temperature logged tests with three replications for each type of material. The fuel in the burnings was peat on a bottom of sand. Flint showed a more drastic effect from heat compared with the other materials. Slate seems to have greater tendencies to change to darker colour and luster at lower temperatures than the other materials.
Yoga och isometrisk uthållighet i bål : Yogautövningens påverkan på den fysiska och mentala allmänhälsan
Abstract The core is the center of gravity in our body. Injuries and overload in the joints, is the most common reason for not be able to work in Sweden today. A god strength capacity in the core is important for secure and effective movements, as well for active athletes, as for non athletes. The increased number of employees, who report in sick today, has been correlated with psychological bad health. New methods to deal with mental and physical health problems among people can indicate to the fact that Yoga in the western world has increased its members, due its spiritual and physical recognition in favor of well being.
BIG SISTER IS WATCHING? En argumentationsanalys av den svenska debatten om ?Chat Control?
The Swedish debate regarding chat control highlights a value conflict between protecting the
safety of children and preserving democratic rights such as privacy and freedom of expression.
This thesis examines key arguments for and against the proposed EU CSAM-regulation,
analyzing them through a normative argumentation analysis method. The analysis is based on
the Swedish constitution, representing the common values of Swedish society. The study
reconstructs arguments from four debate articles and evaluate them according to their relevance
and validity, which makes up the arguments? total evidential strength.
Effekterna av praktisk ocklusionsträning periodiserat med ett traditionellt styrketräningsprogram på anaerob prestation
Background: Practical blood flow restriction (pBFR) combined with resistance training has been proven to facilitate muscle strength despite training at low intensity. However, research investigating the effects of long-term pBFR-training and its periodization with strength training (ST) at a higher intensity is lacking, as well as the effects of occlusion training on blood lactate levels (BLL) over time.Purpose: To compare the effects of 2 weeks of pBFR training followed by 2 weeks of ST (BFR-ST) with 2 weeks of ST followed by 2 weeks of pBFR training (ST-BFR) on anaerobic performace and BLL.Method: 5 adults (age 23 ± 2 years) with a minimum of 1 year of ST experience were recruited and randomized into BFR-ST (n=2) or ST-BFR (n=3). Anaerobic performance was measured using a 30-s Wingate-test and BLL samples were collected <1 and 5 minutes post-Wingate. Data and samples were collected before the intervention and after the 2 protocols.Results: No differences were seen between groups in anaerobic output or BLL after 4 weeks of training (p>0,1 for all values). A decrease in time to peak power (tPP) were seen in both groups with an advantage for BFR-ST (-37 ± 8 %) over ST-BFR (-27 ± 22 %).