Aeronautical engineering, a continuing bibliography with indexes

This bibliography lists 419 reports, articles and other documents introduced into the NASA scientific and technical information system in March 1985

Memcapacitors

Mestrado em Engenharia Eletrónica e TelecomunicaçõesThe present work aims to continue the study of memory devices, initiated with the prediction of the existence of memristors by Leon Chua in 1971, with the study and characterization of memcapacitors as a semiconductor two-terminal device, characterized by the non-linear relation between charge and voltage, which also present the ability to remember the voltage or charge that passes through the device, graphically represented by a graphic with hysteresis characteristics, also presenting a variable capacitance in function of the charge applied in its terminals. Here, a characterizationof the response functions to a sinusoidal periodic input with variable frequency to three mathematical models of memcapacitive systems is performed: given a memcapacitor in series with an ac input voltage source, the respective hysteresis charge-voltage plots are studied by simulations in the MATLAB environment. Next, a classification of the hysteresis plots in function of its geometry is performed, given that the crossing of such graph in the (0.0) point defines it as a type I or type II hysteresis loop. The analysis continues with the morphological identification of the area of the hysteresis curve of the first model, by varying amplitude and frequency of the input source, in such a way to compare the other models with the ideal one, as well as to take the critical frequencis from which the memcapacitance becomes constant, and thus the system becomes linear, by making the hysteresis curve to become a straight line. The area of the first model was taken by calculations with the Green theorem.O presente trabalho propõe-se a continuar o estudo dos dispositivos de memória, iniciado com a predição dos memristors por Leon Chua em 1971, por meio do estudo e caracterização dos memcapacitores como dispositivos semicondutores de dois terminais, caracterizados pela relação não linear entre carga e tensão, que apresentam capacidade de recordar a tensão ou corrente que passa pelo dispositivo, graficamente representado em forma de um gráfico com características de histerese, aprensentando também capacitância variável em função da carga aplicada em seus terminais. Aqui, uma caracterização das funções de resposta a uma entrada periódica sinusoidal com frequência variável, para três modelos matemáticos de sistemas memcapacitivos, é realizada: dado um memcapacitor em série com uma tensão de entrada ac, estuda-se as respectivas funções de histerese carga-tensão por meio de simulação em MATLAB. Em seguida, é realizada uma classificação das curvas de histerese em função da sua geometria, em que a passagem do gráfico no ponto (0,0), de origem dos planos, o define como tipo I ou tipo II. A análise prossegue com a identificação morfológica da área das curvas de histerese obtidas dos primeiro modelo teóricos em causa, variando-se, para isso, amplitude e frequência de entradas, de modo a se comparar os outros dois modelos restantes com este modelo ideal, ao mesmo tempo em que se deseja obter as frequências críticas de cada modelo, ou seja, as frequências e amplitudes a partir das quais a memcapacitância torna-se constante, e o sistema em causa, linear, fazendo então a curva de histerese degenerar para uma reta. A área do primeiro modelo foi calculada através de um algoritmo que calcula a área da curva por meio do Teorema de Green

Intelligent instrumentation, control and monitoring of precision motion systems

Ph.DDOCTOR OF PHILOSOPH

ATS-4 study program, volume 2 Final report

Systems analysis of Applications Technology Satellite-4 - mission and power profiles, antenna array accuracy and efficiency, failure modes, and weight summarie

Voyager spacecraft system. Preliminary design, volume B /book 2 of 3/ - Alternate designs considered - Telecommunications

Voyager spacecraft trade-off design parameters in telecommunication subsystems and between telecommunication system and other systems - data encoder and data storage system

The Role of Inbound Open Innovation Sources on Innovativeness and Advantage of New Products in Small and Medium Sized Enterprises

This Ph.D. thesis provides a quantitative empirical study based on a theoretical model, which deepens and extends previous models by analyzing the different constructs that concur to innovation performance by utilizing various sources of inbound open innovation in SMEs. It empirically investigates the causal relationship of different sources of inbound open innovation and their effects on new product innovativeness and the effect of new product innovativeness on new product advantage in small and medium-sized enterprises in Petroleum and Gas equipment industry in Iran. The theoretical model considers the relationship between different sources of outside-in (Inbound) open innovation collaborating with external partners like customers, competitors, suppliers, universities, research institutions and consultants, and their separate diverse effects on new product innovativeness and measuring new product innovativeness effect on new product advantage of small and medium-sized enterprises (SMEs) in Petroleum and Gas equipment industry. Furthermore, based on previous studies, this research contributes to the concept of internal R&D capability and firm's innovation performance, this thesis measures the effect of internal R&D expenditures as annual sales percentage on new product innovativeness, which regarded as organizational R&D strengths and intensity in SMEs of Petroleum and Gas equipment industry. In addition, building on previous literature, organizational declarative memory as one of the components of organizational memory, which interacts, with concepts of facts, events, and propositions is considered to measure its effect on new product advantage. Likewise, in order to ensure the robustness of results, several control variables were included in this research. These controls have to be considered as the internal organizational component or external organizational elements. Firm size, technology turbulence, market turbulence, and competition intensity were added as control variables to account for the effects of extraneous factors on new product advantage (NPA). The research method of this study is a survey, causal (Explanatory) and descriptive quantitative research method based on structural equation modeling (SEM). It is based on a quantitative method using partial least square structural equation modeling (PLS-SEM) technique. The survey was done among 150 firms in Petroleum and Gas equipment industry in the Iranian context and the empirical analysis had been done at the firm level. For data collection procedure, the simple random procedure as the sampling method was used between 150 firms in Tehran as the capital region of Iran where the main head offices of these 150 firms are located. 150 SMEs were selected as the target population of this Ph.D. thesis and the dataset was collected from such firms. As the research method is based on partial least square structural equation modeling, (PLS-SEM), the purpose of this research is not only based on predictive approach and forecasting but also to contribute to developing and extending the current existing theory of outside-in (Inbound) open innovation activities in SMEs. This research contributes to theory development of surveying and examining the exploitation of different inbound open innovation sources and their effects on new product innovativeness performance in small and medium-sized enterprises (SMEs). The data collection had been done at the firm level, the CEOs, marketing managers, R&D managers, and new product development managers were the respondents to the questionnaire. The results indicate that not all different types of outside-in (Inbound) open innovation sources positively and significantly affected new product innovativeness in SMEs. This is because of this reason that some sources are financial based which SMEs cannot afford to exploit it inside their firms, and SMEs' weaknesses and challenges in innovation practices arise from their size as well. SMEs in general and in Petroleum and Gas equipment industry in particular in this research according to their small scale and size can limit SMEs potential capacity and organizational capability to use all external sources. Furthermore, SMEs suffer from resource limitation or traditional closed innovation models. SMEs prefer to collaborate with sources that can foster and increase their internal organizational and innovation capabilities and capacities based on partnering/collaborating approach, which do not require investment strategies or investing their financial resources in external innovation sources in order to leverage the level of new product innovativeness. They prefer to use a more collaborative approach and partnership with other external innovation sources rather than exploiting sources, which require financial and monetary sources

Measurement of some radiative properties of solar absorber materials

This work describes, (i) the designing and building of two sets of apparatus, namely a Liquid Nitrogen Cooled Ditectional Emissometer and a Laser-source Spectral Bidirectional Reflectometer (ii) measurements using the above apparatus on Solar selective absorber (Maxorb, Cusorb, Skysorb, Solarcoat- 100), non-selective absorber (Nextel, Solarcoat-50) and metal (Al, Cu and brass) samples. The emissometer incorporates liquid nitrogen cooling of the sample chamber thus reducing the error due to emission from the surroundings and extending the working range of sample temperature down to about 273 K. This instrument also uses a beam chopper with a phase sensitive detection system, and a Golay-cell detector. The overall error in the emittance values measured is estimated to be ± 5%. Using the emissometer all the samples in (ii) above were studied. The directional emittance behaviour of the metals and the non-selective absorbers agree well with theoretical predictions and with measurements made by other workers. In the case of the solar selective absorbers however, a peak in the directional emittance at 20°-30° reported by Hutchins (1979) is not seen in any of the present measurements. It is suggested that the ∈/∈'(0°) vs. ∈'(0°) plot can be used in comparing the emittance properties of solar selective absorbers with their substrate metals. The bidirectional reflectometer incorporates a novel device for mounting, positioning and orienting both the sample and the detector (Sample and Detector Assembly - SDA). The relatively small dimensions of this device compared with that of other bidirertional reflectometers reported makes it convenient to use and also allows it to be housed within a light-tight enclosure that minimizes problems with stray light. Extensive measurements have been made using laser sources at λ - 633 nm and λ - 1152 nm on the same set of samples of solar absorbers (selective and non-selective) studied with the emissometer. Comparison of the bidirectional reflectance characteristics of the solar selective absorbers shows marked differences between the materials. However certain features common to 'specularly' reflecting materials and others common to 'diffusely' reflecting materials have been identified. Materials like Cusorb and Solarcoat-100 show a combination of these. Some of these features are discussed in terms of the surface microstructure data obtained using a scanning electron microscope and a conventional stylus type instrument

A cumulative index to a continuing bibliography on aeronautical engineering

This bibliography is a cumulative index to the abstracts contained in NASA-SP-7037(184) through NASA-SP-7037(195) of Aeronautical Engineering: A Continuing Bibliography. NASA SP-7037 and its supplements have been compiled through the cooperative efforts of the American Institute of Aeronautics and Astronautics (AIAA) and the National Aeronautics and Space Administration (NASA). This cumulative index includes subject, personal author, corporate source, foreign technology, contract, report number, and accession number indexes

Measurement of the Triple-Differential Cross-Section for the Production of Multijet Events using 139 fb^{-1} of Proton-Proton Collision Data at \sqrt{s} = 13 TeV with the ATLAS Detector to Disentangle Quarks and Gluons at the Large Hadron Collider

At hadron-hadron colliders, it is almost impossible to obtain pure samples in either quark- or gluon-initialized hadronic showers as one always deals with a mixture of particle jets. The analysis presented in this dissertation aims to break the aforementioned degeneracy by extracting the underlying fractions of (light) quarks and gluons through a measurement of the relative production rates of multijet events. A measurement of the triple-differential multijet cross section at a centre-of-mass energy of 13 TeV using an integrated luminosity of 139 fb −1 of data collected with the ATLAS detector in proton-proton collisions at the Large Hadron Collider (LHC) is presented. The cross section is measured as a function of the transverse momentum p T , two categories of pseudorapidity η rel defined by the relative orientation between the jets, as well as a Jet Sub-Structure (JSS) observable O JSS , sensitive to the quark- or gluon-like nature of the hadronic shower of the two leading-p T jets with 250 GeV < p T < 4.5 TeV and |η| < 2.1 in the event. The JSS variables, which have been studied within the context of this thesis, can broadly be divided into two categories: one set of JSS observables is constructed by iteratively declustering and counting the jet’s charged constituents; the second set is based on the output predicted by Deep Neural Networks (DNNs) derived from the “deep sets” paradigm to implement permutation invariant functions over sets, which are trained to discriminate between quark- and gluon- initialized showers in a supervised fashion. All JSS observables are measured based on Inner Detector tracks with p T > 500 MeV and |η| < 2.5 to maintain strong correlations between detector- and particle-level objects. The reconstructed spectra are fully corrected for acceptance and detector effects, and the unfolded cross section is compared to various state-of-the-art parton shower Monte Carlo models. Several sources of systematic and statistical uncertainties are taken into account that are fully propagated through the entire unfolding procedure onto the final cross section. The total uncertainty on the cross section varies between 5 % and 20 % depending on the region of phase space. The unfolded multi-differential cross sections are used to extract the underlying fractions and probability distributions of quark- and gluon-initialized jets in a solely data-driven, model- independent manner using a statistical demixing procedure (“jet topics”), which has originally been developed as a tool for extracting emergent themes in an extensive corpus of text-based documents. The obtained fractions are model-independent and are based on an operational definition of quark and gluon jets that does not seek to assign a binary label on a jet-to-jet basis, but rather identifies quark- and gluon-related features on the level of individual distributions, avoiding common theoretical and conceptional pitfalls regarding the definition of quark and gluon jets. The total fraction of gluon-initialized jets in the multijet sample is (IRC-safely) measured to be 60.5 ± 0.4(Stat) ⊕ 2.4(Syst) % and 52.3 ± 0.4(Stat) ⊕ 2.6(Syst) % in central and forward region, respectively. Furthermore, the gluon fractions are extracted in several exclusive regions of transverse momentum