The multi-disciplinary design study: A life cycle cost algorithm

The approach and results of a Life Cycle Cost (LCC) analysis of the Space Station Solar Dynamic Power Subsystem (SDPS) including gimbal pointing and power output performance are documented. The Multi-Discipline Design Tool (MDDT) computer program developed during the 1986 study has been modified to include the design, performance, and cost algorithms for the SDPS as described. As with the Space Station structural and control subsystems, the LCC of the SDPS can be computed within the MDDT program as a function of the engineering design variables. Two simple examples of MDDT's capability to evaluate cost sensitivity and design based on LCC are included. MDDT was designed to accept NASA's IMAT computer program data as input so that IMAT's detailed structural and controls design capability can be assessed with expected system LCC as computed by MDDT. No changes to IMAT were required. Detailed knowledge of IMAT is not required to perform the LCC analyses as the interface with IMAT is noninteractive

Reduced order models for parametric bifurcation problems in nonlinear PDEs

This work is concerned with the analysis and the development of efficient Reduced Order Models (ROMs) for the numerical investigation of complex bifurcating phenomena held by nonlinear parametrized Partial Differential Equations (PDEs) in many physical contexts, from Continuum Mechanics to Quantum Mechanics passing through Fluid Dynamics. Indeed, the reconstruction of the bifurcation diagrams, which highlight the singularities of the equations and the possible coexisting states, requires a huge computational effort, especially in the multi-parameter context. To overcome this issue, we developed a reduced order branch-wise algorithm for the efficient investigation of such complex behaviour, with a focus on the stability properties of the solutions. We applied our approach to the Von K\ue1rm\ue1n equations for buckling plates, the Gross-Pitaevskii equations in Bose-Einstein condensates, the Hyperelastic models for bending beams and the Navier-Stokes model for the flow in a channel. Several issues and questions arise when dealing with the approximation and the reduction of bifurcating phenomena, we addressed them by considering new models and emerging methodologies. In particular, we developed a reduced order approach to deflated continuation method, to efficiently discover new solution branches. We proposed and discussed different Optimal Control Problems (OCPs) to steer the bifurcating behaviour towards desired states. Finally, we exploited a Neural Network approach based on the Proper Orthogonal Decomposition (POD-NN), as an alternative to the Empirical Interpolation Method (EIM), to develop a reduced manifold based algorithm for the efficient detection of the bifurcation points

Le Pteridofite europee: la loro tassonomia e nomenclatura oggi

Gli pteridologi sono tutt'ora in grande disaccordo circa la tassonomia e nomenclatura di alcune famiglie, generi e specie delle Pteridophyta. Esso riguarda anche alcune felci e gruppi affini dell'Europa. Dopo una breve introduzione sulle ragioni di questo disaccordo, viene fatto un confronto (Tab. 1) tra le classificazioni delle famiglie adottate in quattro lavori pertinenti alle pteridofite europee, pubblicati negli ultimi venticinque anni. Il dissenso maggiore esiste tra la classificazione seguita nella Med-Checklist e quelle adottate nei rimanenti lavori. Questi ultimi, tuttavia, discordano principalmente nei riguardi della circoscrizione delle famiglie delle Pteridineae, Dryopteridineae ed Ophioglossales. Le principali differenze tra le famiglie appartenenti a questi taxa sono messe in risalto in alcune illustrazioni (Fig. 1-3) e vengono discusse le differenti possibilità di classificazione di esse. I principali dissensi circa la tassonomia e la nomenclatura dei generi riguardano il trattamento diLycopodium, Botrychium, Cheilanthes, Thelypteris ed Asplenium. Gli schemi (Tab. 2-4) mostrano le diverse vedute degli autori di sei opere pubblicate negli ultimi venticinque anni nei riguardi della circoscrizione dei tre generi ultimi nominati. Aleune illustrazioni (Fig. 4- 9) mettono in risalto le caratteristiche distintive di Cheilanthes edAsplenium dai generi ad essi affini, Viene sostenuta la scissione delle Cheilanthes europee (Tab. 2, Fig. 4) in tre generi. Uno di essi è Notholaena; il problema della sua tipificazione viene estesamente discusso e si giunge alla conclusione cheN. marantae deve essere il tipo di questo nome generico. Thelypteris (Tab. 3), come rappresentato in Europa, dovrebbe essere scisso in cinque generi; uno di essi è Oreopteris denominato in passato Lastrea. Viene discusso il problema del trattamento tassonomico dei gruppi satelliti del genere Asplenium (Tab. 4, Fig. 5-9) ed il riconoscimento di essi come generi indipendenti (Ceterach, Pleurosorus, Phyllitis ePhyllilopsis) viene considerata come la soluzione più giusta. Per quanto riguarda le specie, viene presa in considerazione soltanto la nomenclatura di Cheilanthes maderensis e di Asplenium viride. Ambedue questi nomi possono essere ancora usati, sebbene aleuni autori li abbiano recentemente rimpiazzati rispettivamente con i nomi Cheilanthes pteridioides ed Asplenium trichomanes-ramosum.Great disagreement is still extant among the pteridologists about the taxonomy and nomenclature of some families, genera and species of the Pteridophyta. It also concerns, of course, some ferns and fern-allies from Europe. After a short introduction on the reasons of this disagreement, a comparison (Tab. 1) is made between the classifications of the families adopted in four works chiefly dealing with the European Pteridophytes, published in the last twenty-five years. The main dissent exists between the classification followed in the Med-Checklist and those adopted in the remaining works. The latter chiefly disagree, however, with regard to the circumscription of the famílies of the Pteridineae, Dryopteridineae and Ophioglossales. The main differences among the famílies belonging to each of these taxa are shown by means of some illustrations (Fig. 1-3). The possible arrangement of them is discussed. The main disagreements about the taxonomy and nomenclature of the genera regard the treatment of Lycopodium, Botrychium, Cheilanthes, Thelypteris and Asplenium. Three tables (Tab. 2-4) show the different views of the authors of six works published in the last twenty-five years, about the circumscription of the last three genera mentioned. Some illustrations (Fig. 4-9) point out the characteristics of Cheilanthes and Asplenium which distinguish them from their allied genera. The splitting of the European Cheilanthes (Tab. 2, Fig. 4) into three genera is supported. One of them isNotholaena; the problem of its typification is discussed at lenght, and the conclusion is reached that N. marantae must be the type of this generic name. Thelypteris (Tab. 3), as represented in Europe, ought to be split into five genera; one of them is Oreopteris previously named Lastrea. The problem of the taxonomic treatment of the satellite groups of the genus Asplenium (Tab. 4, Fig. 5-9) is discussed, and the recognition of them as independent genera (Ceterach, pleurosorus, Phyllitis and phyllitopsis) is regarded as a well-grounded solution. As regards the species, only the nomenclature of Cheilanthes maderensis and Asplenium viride is taken into account Both names can be still used, although some authors have recently replaced them with the names Cheilanthes pteridioides and Asplenium trichomanes-ramosum respectively

A Reduced Order Modeling Technique to Study Bifurcating Phenomena: Application to the Gross--Pitaevskii Equation

We propose a computationally efficient framework to treat nonlinear partial differential equations having bifurcating solutions as one or more physical control parameters are varied. Our focus is on steady bifurcations. Plotting a bifurcation diagram entails computing multiple solutions of a parametrized, nonlinear problem, which can be extremely expensive in terms of computational time. In order to reduce these demanding computational costs, our approach combines a continuation technique and Newton's method with a reduced order modeling (ROM) technique, suitably supplemented with a hyperreduction method. To demonstrate the effectiveness of our ROM approach, we trace the steady solution branches of a nonlinear Schr\uf6dinger equation, called the Gross--Pitaevskii equation, as one or two physical parameters are varied. In the two-parameter study, we show that our approach is 60 times faster in constructing a bifurcation diagram than a standard full order method

Pengembangan Lembar Kegiatan Peserta Didik (LKPD) Berbasis Search, Solve, Create And Share Pada Pokok Bahasan Kesetimbangan Ion dan pH Larutan Garam

Penelitian ini bertujuan untuk mengembangkan bahan ajar berupa lembar kegitan peserta didik (LKPD) berbasis search, solve, create and share (SSCS) pada pokok bahasan kesetimbangan ion dan pH larutan garam untuk kelas XI tingkat SMA/MA. Jenis penelitian yang digunakan yaitu penelitian pengembangan (Research and Development) dengan model pengembangan 4-D. Objek penelitian yaitu LKPD berbasis SSCS. Instrumen pengumpulan data berupa lembar validasi yang diberikan kepada tiga orang validator dan lembar respon pengguna kepada dua orang guru mata pelajaran kimia dan 20 orang peserta didik kelas XII MIPA SMA dan MA. Teknik analisis data yaitu dengan cara menghitung skor persentase penilaian validasi dan respon pengguna. Hasil penelitian menunjukkan bahwa LKPD berbasis SSCS yang dikembangkan memenuhi kriteria valid dari aspek penilaian substansi isi, kelayakan karakteristik SSCS, kebahasaan, penyajian dan kegrafisan dengan persentase skor keseluruhan sebesar  93,01 %. Respon pengguna berdasarkan lembar tanggapan guru dan tanggapan peserta didik masing-masing memperoleh skor 92,5 % dan 91,43%

Disease of the Year : Differential Diagnosis of Uveitic Macular Edema

Uveitic cystoid macular edema (UME) is an important cause of visual morbidity among patients with both infectious and non-infectious uveitis. UME may be associated in more than 30% cases of active uveitis. However, even patients with minimal features of intraocular inflammation may develop recurrent or chronic UME. Therefore, the evaluation and management of UME in patients with uveitis may be challenging. A number of vitreoretinal pathologies may result in UME and accumulation of fluid in the intra- or subretinal space. These need to be carefully distinguished from each other so that appropriate management can be initiated. All types of uveitis, including anterior uveitis (where the primary site of inflammation is not in the posterior segment) can present with UME. Other conditions such as diabetes, and surgery, can present with macular edema. This index review highlights various differential diagnoses of UME and provides illustrative case examples with multimodal imaging evaluation

Efficient computation of bifurcation diagrams with a deflated approach to reduced basis spectral element method

The majority of the most common physical phenomena can be described using partial differential equations (PDEs). However, they are very often characterized by strong nonlinearities. Such features lead to the coexistence of multiple solutions studied by the bifurcation theory. Unfortunately, in practical scenarios, one has to exploit numerical methods to compute the solutions of systems of PDEs, even if the classical techniques are usually able to compute only a single solution for any value of a parameter when more branches exist. In this work, we implemented an elaborated deflated continuation method that relies on the spectral element method (SEM) and on the reduced basis (RB) one to efficiently compute bifurcation diagrams with more parameters and more bifurcation points. The deflated continuation method can be obtained combining the classical continuation method and the deflation one: the former is used to entirely track each known branch of the diagram, while the latter is exploited to discover the new ones. Finally, when more than one parameter is considered, the efficiency of the computation is ensured by the fact that the diagrams can be computed during the online phase while, during the offline one, one only has to compute one-dimensional diagrams. In this work, after a more detailed description of the method, we will show the results that can be obtained using it to compute a bifurcation diagram associated with a problem governed by the Navier-Stokes equations