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The paper aims to extend the knowledge base for design and optimization of Star grain which is well known for its simplicity, reliability and efficiency. Star grain configuration is considered to be among the extensively used configurations for the past 60 years. The unexplored areas of treatment of ballistic constraints, non-neutral trace and freedom from use of generalized design equations and sensitivity analysis of optimum design point are treated in detail to bridge the gap. The foremost purpose is to expand the design domain by considering entire convex Star family under both neutral and non-neutral conditions.

This research effort optimizes Star grain configuration for use in Solid Rocket Motors with ballistic objective function (effective total impulse) and parametric modelling of the entire convex Star grain family using solid modelling module. Internal ballistics calculations are performed using equilibrium pressure method. Optimization process consists of Latinized hypercube generated initial population and Swarm Intelligence optimizer’s ability to search design space. Candidate solutions are passed to solid modelling module to simulate the burning process. Optimal design points, critical geometrical and important ballistic parameters (throat diameter, burn rate, characteristic velocity and propellant density) are then tested for sensitivities through Monte Carlo simulation.

The proposed approach takes the design of Star grain configuration to a new level with introduction of parametric modelling and sensitivity analysis, thus, offering practical optimum design points for use in various mission scenarios. The proposed design and optimization process provides essential data sets which can be useful prior to the production of large number of solid rocket motors. Results also advocate the adequacy of design from engineering perspective and practicality.

Results showed that few design parameters are sensitive to uncertainties. These uncertainties can be investigated in future by a robust design method.

Monte Carlo simulation can prove to be vital considering the production of a large number of motor units and enlightens the necessity to obtain statistical data during manufacturing.

This paper fulfils long-sought requirement on getting free from use of generalized set of equations for commonly used Star grain configurations.

This paper aims to determine the regression rate using wax fuels for three different grain configurations and find a suitable grain port design for hybrid rocket application.

The design methodology of this work includes different grain port designs and subsequent selection of solid fuels for a suitable hybrid rocket application. A square, a cylindrical and a five-point star grained were designed and prepared using paraffin and beeswax fuels. They were tested in a laboratory-scale rocket with gaseous oxygen to study the effectiveness of solid fuels on these grain structures. The regression rate by static fire testing of these wax fuels was analyzed.

Beeswax performance is better than that of paraffin wax fuel for all three designs, and the five-slotted star fuel port grain attained the best performance. Beeswax fuel attained an average regression rate ≈of 1.35 mm/s as a function of oxidizer mass flux Gox ≈ 111.8 kg/m² s and for paraffin wax 1.199 mm/s at Gox ≈ 121 kg/m² s with gaseous oxygen. The local regression rates of fuels increased in the range of 0.93–1.194 mm/s at oxidizer mass flux range of 98–131 kg/m² s for cylindrical grain, 0.99–1.21 mm/s at oxidizer mass flux range of 96–129 kg/m2s for square grain and 1.12–1.35 mm/s at oxidizer mass flux range of 91–126 kg/m² s for a star grain. A complete set of the regression rate formulas is obtained for all three-grain designs as a function of oxidizer flux rate.

The experiment has been performed for a lower chamber pressure up to 10 bar.

Different grain configurations were designed according to the required dimension of the combustion chamber, injector and exhaust nozzle of the design of a lab-scale hybrid rocket, and input parameters were selected and analyzed.

The purpose of this paper is to study the correlation between abrasive wear resistance, contact configuration and grain size of aluminium alloy.

Different aluminium alloy with different grain size has been tested using a scratch test. Comparison between scratch parameters, especially scratch depth and grain size aluminium alloy, has been made. Two indenters were used: conical and spherical indenter.

Correlation between grain size of aluminium alloy, configuration contact and abrasive wear resistance has been discussed. This study can be useful for choosing material which can provide better abrasive wear resistance.

This study can be a reference both practically and academically. A similar study has been made in order to investigate the effect of hardness in abrasive wear resistance. However, the importance of microstructure and especially the grain size of aluminium alloy have been taken into account.

This paper reviews some continuing IBM study efforts conducted on surface mounted Leadless Chip Carrier (LCC) packaging for use in high density, high thermal stress military environments. The paper presents some designs, materials and solder joint processing considerations that can affect solder joint fatigue life. Also discussed are some thermal cycling test limitations, important properties of solder failure mechanisms and finally some technical concerns with both WS 6536E and DoD 2000 specifications as to their limitations with future surface mounted technologies.

The purpose of this paper is to investigate the driving mechanisms for crack propagation regarding the related microstructures. Cracks in white etching layers have been found at the surface of submerged steel blades subjected to frictional sliding conditions.

In-situ monitoring revealed a fluctuation between mixed lubrication and hydrodynamic lubrication conditions. One lamella including a crack tip was prepared for transmission electron microscopy (TEM) using focused ion beam milling. Transmission electron microscope analysis was performed with the aim to understand the characteristics of the crack propagation, especially considering the influence of the microstructural configuration (grain refinement, carbides, martensite and ferrite grains).

The investigations have shown a grain-refined plastically deformed layer (friction martensite with grain sizes of < 100 nm) which influences the propagation direction of cracks introduced at the frictionally stressed surface. Thereby, the crack propagation is dominantly parallel to the margin of the grain-refined martensitic layer at the surface and the base material. Cracks were split into side cracks what mostly appears at present carbides. In this case, the crack propagation might strike through the carbide or separate it from the matrix due to the mechanical misfit.

For obtaining the results of this paper, a very special preparation of tribologically stressed samples was performed. Accordingly, specific findings of the crack propagation behavior under such conditions were achieved and are documented in the presented work. Moreover, the described crack propagation process is a combination of several mechanisms which occur in very limited region underneath the surface and are investigated by high-resolution TEM.

During any design phase, the associated process variations and uncertainties can cause the design to deviate from its expected performance. The purpose of this paper is to propose a robust design optimization (RDO) strategy for the 3D grain design of a dual thrust solid rocket motor (DTRM) under uncertainties in design parameters.

The methodology consists of design of 3D complex grain geometry and hybrid optimization approach through genetic algorithm, globally and simulated annealing, locally considering the uncertainties in design parameters. The robustness of optimized data is measured for a worst case parameter deviation using sensitivity analysis through stochastic Monte Carlo simulation considering variance of design parameters mean.

The important achievement that can be associated with this methodology is its ability also to evaluate and optimize the propulsion system performance in a complex scenario of intricate 3D geometry under uncertainty. The study shows the objective function to maximize the average thrust in dual levels could be achieved by the proposed optimization technique while satisfying constraints conditions. Also, this technique proved to be a great help in reducing the design space for optimization and increasing the computational quality.

This is the first paper to address the dual thrust solid rocket motor grain design under uncertainties using robust design and hybrid optimization approach.

This study aims to present a method for conceptual design and simulation of hybrid propellant motors.

The design methodology is based on previous studies and thermo-physical governor relations, and also a computational code that was derived to simulate the performance of designed system.

Conceptual design algorithm for space hybrid propellant systems and method of performance simulation are findings of this study.

Results of this study are applicable for design process of space systems with hybrid propulsion. Also, simulation results can help the users to improve the performance weaknesses.

This study shows the implementation of present algorithm for a specified space mission and also study on variation of performance parameters.

The purpose of this paper is to explore how the emphases given to the levers of control when monitoring product development (PD) are combined with each other, with the type of PD strategy formation and with the degree of innovativeness experienced by the firm. Moreover, the paper aims at identifying those configurations that are equifinal and superior to others in terms of PD and organizational performance.

Data (n = 468) are collected through a structure written questionnaire and analyzed through cluster analysis. Robustness tests investigate the stability of the results across different cluster method choices.

The paper unravels three configurations: A framing firms cluster, a fatalist firms cluster and a meticulous firms cluster. The first and the third cluster outperform the second cluster in terms of performance.

Limitations of the paper relate to the possible response bias, the measurement of the variables, the subjectivity in cluster method choices and the static and non-causal nature of results. Future studies are called to validate the findings.

Firms with a partially intended and partially emergent PD strategy formation process and high innovativeness should place high emphasis to the PD beliefs and boundary systems. Firms with a prevailing intended PD strategy formation and a medium innovativeness should emphasize diagnostic and interactive control systems for PD.

In contrast to previous studies, this paper addresses the peculiarities of one specific control problem, i.e. the conflicting control demands that management has to address in PD.

The purpose of this paper is to describe research into the problem of creating computer structural models of magnetic microfibres. The main goal of the research is to create the universal generator of computer structural models for whole bundles of magnetic microfibres.

The paper presents the algorithm of magnetic microfibres computer modelling. It covers both finite element method (FEM) and reluctance network method. Because microfibres with ferromagnetic grains have very complicated 3D structure, the quickest possible method was chosen.

The results focus on the methodology presented in the paper which can be implemented in building 3D equivalent B/H curve of the microfibres set by use of field method – combining reluctance network method and FEM. Defining the proper magnetic B/H curves of magnetic fibres will enable the production of smart and resistant clothes.

To date there are only measurements characteristics of B/H curve of magnetic microfibres. This paper proposes an innovatory way of determining magnetic microfibres parameters. This universal computer model allows the evaluation of the limiting value of magnetization (magnetic permeability, etc.).

The purpose of this paper is to present an approach where a novel user modeling wizard for people with motor impairments is used to gain a deeper understanding of very specific (touch-based and touchless) interaction patterns. The findings are used to set up and fill a user model which allows to automatically derive an application- and user-specific configuration for natural user interfaces.

Based on expert knowledge in the domain of software/user interfaces for people with special needs, a test-case –based user modeling tool was developed. Task-based user tests were conducted with seven users for the touch-based interaction scenario and with five users for the touchless interaction scenario. The participants are all people with different motor and/or cognitive impairments.

The paper describes the results of different test cases that were designed to model users’ touch-based and touchless interaction capabilities. To evaluate the tool’s findings, experts additionally judged the participants’ performance (their opinions were compared to the tool’s findings). The results suggest that the user modeling tool could quite well capture users’ capabilities.

The paper presents a tool that can be used to model users’ interaction capabilities. The approach aims at taking over some of the (very time-consuming) configuration tasks consultants have to do to configure software according to the needs of people with disabilities. This can lead to a wider accessibility of software, especially in the area of gesture-based user interaction.

Part of the approach has been published in the proceedings of the Interactional Conference on Advances in Mobile Computing and Multimedia 2014. Significant additions have been made since (e.g. all of the touchless interaction part of the approach and the related user study).