Burning Rate Modifiers to Tailor Combustion of ADN/AN-Based Solid Propellants

This paper presents a study, carried out in the framework of the H2020 european project GRAIL, on thermal and catalytic decomposition of a solid ADN/AN mixture. Decomposition pathways of the mixture are proposed thanks to thermal analyses coupled with mass spectrometry. Thirty-four burning rate modifiers have been investigated using thermal analyses. This led to the selection of five candidates considered as promising additives: nano-CuO, CuO, Cr2Cu2O5, ZnO and ferrocene. Finally, a bicatalytic system with nano-CuO and ferrocene was considered for possible improvement of the decomposition. It prove to display a much attractive behavior towards the decomposition of this oxidizer mixture

How do banks assess entrepreneurial competence? The role of voluntary information disclosure

This research adds to the literature on relationship lending in the small business context by discussing the roles of entrepreneurial competence and voluntarily disclosed information as determinants of credit access. More specifically, we propose that the loan manager’s evaluation of the information voluntarily disclosed by the entrepreneur is an important complement to publicly available financial data and soft information collected through observation and third parties in framing the loan manager’s perception of the entrepreneur’s competence. Further, we argue that banks charge lower interest rates if the loan manager perceives the entrepreneur to be competent. Econometric analysis based on 433 bank-firm relationships supports these hypothesised relationships. The results imply that entrepreneurs need to communicate their competence effectively to loan managers, and that banks should utilise their loan managers’ personal evaluations as inputs to lending decisions

From Queen of Heaven to a virtuous Servant. Mariological changes in the Swedish reformatory writings of the 16th century

This thesis examines the mariological changes of the Swedish reformatory process in the 16th century. Two main questions are asked: What image, or images, of the virgin Mary are mediated in the religious literature of the 16th century, and how do these images correspond to Lutheran theology? A selection of reformatory prayers, sermons and hymns have been closely read and analysed. Focal points have been on writings connected to Mary and her feast days, such as the Annunciation. Within the medieval context Mary is elevated with goddesslike attributes. She is Coredemptrix, actively participating in the salvation of all people. This study concludes that within the Swedish reformation a new and reconstructed image of the virgin Mary is developed. In the reformatory writings Mary is introduced as a humble servant, a human among others, who from God have been honored with special grace. She is praised in the meaning that she has been chosen by God. It is emphasised that it is not by her own abilities that she is dignified, but only by her god given grace. The Swedish reformers erase the image of Mary as Coredemptrix and turn her into an example of a virtuous Christian woman. The results suggest that the new image of Mary is not without relevance. This interpretation of the reformed virgin Mary demonstrates the importance of Luther’s doctrine of vocation. In the analysed material the virgin Mary acts as an example for one who lives in her vocation. The Swedish reformers do not only emphasise her obedience to God, calling her to be the mother of his son, but also Mary’s care for her fellow human beings, her dedication to her household chores and raising her child. Within the reformatory writings Mary is used as an example of the gifts and grace that comes with following one´s vocation

#showtheworld : Evolving storytelling and giving voice in art education

Projektet #visavärlden fokuserar lika mycket på att lära ut tolkning om konst som det själva skapandet av egen konst. Genom moment där eleverna exponeras för, tolkar och diskuterar konst skaffar de kunskaper och inspiration för att sedan producera sina egna verk. Moment som 'duschen', där de blir översköljda av olika verk och konstnärer, 'bildpromenaden', där de analyserar och tolkar verk utifrån vad de ser och tänker, och 'frågorna', ett hjälpmedel för eleverna att själva komma fram till vad de tycker är viktigt och vill dela med sig. Efter att ha skaffat kunskap och insikt har eleverna i projektet jobbat flitigt för att kunna ställa ut sina verk. Detta är deras berättelser, röster och perspektiv på världen. Nyckelordet i detta arbete är “att berätta”, vilket involverar ett narrativ, en röst och identitet. I skolans läroplan finns skrivet att dessa begrepp skall bearbetas i bildämnet. Genom att själv berätta och ta del av andras berättelser ökar förmågan att kunna se och lära känna sig själv vilket är en förutsättning för att kunna reflektera över sin egen värld och identitet och bli öppen för andra människors liv och livsberättelser. Men både som lärare och elev har jag saknat en pedagogisk metod som öppnar möjligheten för barn och ungdomar att arbeta med sina berättelser och sin identitet. Detta arbete är ett svar på denna avsaknad

Improving the Mechanical Properties of Composite Rocket Propellants

Solid composite rocket propellants usually contain ammoniumperchlorate embedded in an elastic polymer binder. The bindercan be based on a liquid prepolymer such as hydroxyl-terminatedpolybutadiene, HTPB, or poly(3-nitratomethyl-3-methyl oxetane,PolyNIMMO. HTPB is today widely used for this purpose whereasPolyNIMMO has not yet found its way to an application. Bothprepolymers can be cured with diisocyanates to formpolyurethane rubber, yielding solid and elastic rocketpropellants. It is essential that the solid propellant has goodmechanical properties to ensure that the rocket will perform asintended. The propellant must also retain its elasticproperties down to the minimum service temperature and thus alow glass transition temperature is important. In fact, themajor cause of failure of solid rocket motors is linked to themechanical properties of the propellants. HTPB has a very lowglass transition temperature but in some applications itstensile strength is insufficient. PolyNIMMO, on the other hand,has too high a glass transition temperature and a suitableplasticizer is needed. The purpose of this work is to increasethe knowledge of the mechanical properties of polymers bystudying how to increase the tensile strength of HTPB and howto decrease the glass transition temperature of PolyNIMMO. The tensile strength of HTPB was studied by increasing thehard segment content, 1,4-butanediol and 1,4-cyclohexanedimethanol being used as chain extenders. The materials werecrosslinked with either isophorone diisocyanate,1,6-hexamethylene diisocyanate or dicyclohexylmethane4,4'-diisocyanate. The results show that the tensile strengthincrease strongly with the addition of up to two moles of diolper mole HTPB. The highest tensile strength was obtained byusing dicyclohexylmethane 4,4'-diisocyanate and1,4-butanediol. The depression of the glass transition temperature ofPolyNIMMO was studied by using a new energetic plasticizer,2,2-dinitro-1,3-bis-nitrooxy-propane. Two commercial energeticplasticizers, namely bis(2,2-dinitropropyl) acetal/formal andN-N-butyl-N-(2-nitroxy-etyl)nitramine were used for comparison.2,2-Dinitro-1,3-bis-nitrooxy-propane andN-N-butyl-N-(2-nitroxy-etyl)nitramine were found to interactstrongly with PolyNIMMOand they were thus very effective inlowering the glass transition temperature.Bis(2,2-dinitropropyl) acetal/formal on the other hand was noteffective, and the depression of the glass transitiontemperature in this case was due only to dilution of thesample.QCR 20161026</p

Influence of Water Content in an ADN Based Liquid Monopropellant on Performance Characteristics

Hydrazine is advantageous for attitude control systems of satellites because it is space storable for long times and the developed thrusters are reliable for long term operations. Unfortunately hydrazine is very difficult to handle on ground due to its very high toxicity. Especially with regard to the REACH regulation of the European Community, which has passed some years ago, Hydrazine is on the candidate list of substances whose use could be limited in future. Thus strong research efforts have to be conducted today to find and to qualify alternative propellants, which have significantly simpler handling characteristics, are less toxic, environmentally benign and have similar or even better performance characteristics. One of the most promising candidates to replace hydrazine is the ADN based ionic liquid FLP-106, which is a monopropellant and has been developed by FOI. This monopropellant has a higher Isp in comparison to hydrazine and to LMP-103S which is currently used by the ECAPS company from Sweden. Also FLP-106 has a lower vapor pressure than LMP-103S. Thrusters using ionic liquid propellants are working with heated catalysts to decompose the propellant. One of the main drawbacks of this design is the lack of cold-start capability. Additionally, the high combustion temperature is a concern, possibly requiring high-temperature alloys like Iridium/Rhenium. FLP-106 consists of 64.6 % ADN (ammonium dinitramide), 23.9 % water and 11.5 % of a low volatile hydrocarbon fuel. In order to use simpler materials with lower melting points the combustion temperature of FLP-106 can be decreased by increasing the water content in the propellant. However, the increased water content will decrease the specific impulse and may also influence the ignition properties