1,721,064 research outputs found
Raport preliminar de cercetare arheologică la Jdioara
No full textBejan Adrian. Raport preliminar de cercetare arheologică la Jdioara. In: Materiale şi cercetări arheologice, N°13 1979. A XIII - A sesiune anuală de rapoarte. pp. 341-342
Cetatea feudală Jdioara, Sat. Jdioara, Com. Criciova, jud. Timiş / Festung Jdioara (Dorf Jdioara, Gem. Criciova, Kr. Timiş)
No full textBejan Adrian. Cetatea feudală Jdioara, Sat. Jdioara, Com. Criciova, jud. Timiş / Festung Jdioara (Dorf Jdioara, Gem. Criciova, Kr. Timiş). In: Materiale şi cercetări arheologice, N°14 1980. A XIV-A sesiune anuală de rapoarte. pp. 514-523
Şantierul arheologic Hodoni-Pustă / Die Ausgrabungen von Hodoni-Pustă
No full textBejan Adrian, Benea Doina. Şantierul arheologic Hodoni-Pustă / Die Ausgrabungen von Hodoni-Pustă. In: Materiale şi cercetări arheologice, N°15 1983. A XV-A sesiune anuală de rapoarte, Muzeul jedeţean Braşov – 1981. pp. 388-394
Aşezarea din secolele III–IV e.n. de la Hodoni-Pustă, Jud. Timiş / Die Siedlung des III.–IV. Jahrhunderts u.z. von Hodoni-Pustà (Kreis Temesch). Vorzeitiger archäologischer Vorschungsbericht — 1979
No full textBejan Adrian. Aşezarea din secolele III–IV e.n. de la Hodoni-Pustă, Jud. Timiş / Die Siedlung des III.–IV. Jahrhunderts u.z. von Hodoni-Pustà (Kreis Temesch). Vorzeitiger archäologischer Vorschungsbericht — 1979. In: Materiale şi cercetări arheologice, N°14 1980. A XIV-A sesiune anuală de rapoarte. pp. 366-372
Aşezarea din secolele III-IV e.n. de la Timişoara-Cioreni / Eine Ansiedlung aus dem 3.-4. Jh.u.Z. bei Timişoara-„Cioreni”
No full textBejan Adrian, Benea Doina. Aşezarea din secolele III-IV e.n. de la Timişoara-Cioreni / Eine Ansiedlung aus dem 3.-4. Jh.u.Z. bei Timişoara-„Cioreni”. In: Materiale şi cercetări arheologice, N°15 1983. A XV-A sesiune anuală de rapoarte, Muzeul jedeţean Braşov – 1981. pp. 381-383
The natural emergence of vascular design with turbulent flow
No full textHere we show that vascular design emerges naturally when a volume is bathed by a single stream in turbulent flow. The stream enters the volume, spreads itself to bathe the volume, and then reconstitutes itself as a single stream before it exits the volume. We show that in the pursuit of a smaller global flow resistance and larger volumes, the flow architecture changes stepwise from a stack of identical elements bathed in parallel flow (like a deck of cards) to progressively more complex structures configured as trees matched canopy to canopy. The transition from one architecture to the next occurs at a precise volume size, which is identified. Each transition marks a decrease in the rate at which the global flow resistance increases with the volume size. This decrease accelerates as the volume size increases. The emergence of such vasculatures for turbulent flow is compared with the corresponding phenomenon when the flow is laminar. To predict this design generation phenomenon is essential to being able to scale up the designs of complex flow structures, from small scale models to life size models.</p
Design of Latent Thermal Energy Storage Systems
No full textThis dissertation documents the results of a theoretical and numerical study of time dependent storage of energy by melting a phase change material. The heating is provided along invading lines, which change from single-line invasion to tree-shaped invasion. Chapter 2 identifies the special design feature of distributing energy storage in time-dependent fashion on a territory, when the energy flows by fluid flow from a concentrated source to points (users) distributed equidistantly on the area. The challenge in this chapter is to determine the architecture of distributed energy storage. The chief conclusion is that the finite amount of storage material should be distributed proportionally with the distribution of the flow rate of heating agent arriving on the area. The total time needed by the source stream to ‘invade’ the area is cumulative (the sum of the storage times required at each storage site), and depends on the energy distribution paths and the sequence in which the users are served by the source stream. Chapter 3 shows theoretically that the melting process consists of two phases: “invasion” thermal diffusion along the invading line, which is followed by “consolidation” as heat diffuses perpendicularly to the invading line. This chapter also reports the duration of both phases and the evolution of the melt layer around the invading line during the two-dimensional and three-dimensional invasion. It also shows that the amount of melted material increases in time according to a curve shaped as an S. These theoretical predictions are validated by means of numerical simulations in chapter 4. This chapter also shows that the heat transfer rate density increases (i.e., the S curve becomes steeper) as the complexity and number of degrees of freedom of the structure are increased, in accord with the constructal law. The optimal geometric features of the tree structure are detailed in this chapter. Chapter 5 documents a numerical study of time-dependent melting where the heat transfer is convection dominated, unlike in chapter 3 and 4 where the melting is ruled by pure conduction. In accord with constructal design, the search is for effective heat-flow architectures. The volume-constrained improvement of the designs for heat flow begins with assuming the simplest structure, where a single line serves as heat source. Next, the heat source is endowed with freedom to change its shape as it grows. The objective of the numerical simulations is to discover the geometric features that lead to the fastest melting process. The results show that the heat transfer rate density increases as the complexity and number of degrees of freedom of the structure are increased. Furthermore, the angles between heat invasion lines have a minor effect on the global performance compared to other degrees of freedom: number of branching levels, stem length, and branch lengths. The effect of natural convection in the melt zone is documented.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The Constructal Evolution of the Cross Sections of Jets toward the Round Shape
Get PDFThis thesis reports a theoretical and experimental study of laminar and turbulent jet flows issuing from a slender rectangular nozzle. According to constructal law of design and evolution in nature, all flow systems have a tendency to evolve into configurations that facilitate flow access over time. Therefore this law predicts that when a jet initially has a flat cross-section, further downstream it would evolve toward round cross-sections for the purpose of enhancing the transfer of momentum (movement) perpendicular to the jet, i.e. to enhance mixing. The first part of the study consists of numerical simulations conducted in range of Re = 10, 20 and 30 for laminar jet flow, and Re = 500, 1000, 2000, 5000 and 10000 for turbulent jet flow, where Re is the Reynolds number based on nozzle spacing and velocity. In the second part, the phenomenon is studied based on scale analysis. The chief conclusions of this part is that the prediction of the transition from flat to round cross-section is in agreement with the results produced by numerical experiments. The experimental observations of jet flows are in accordance with the constructal law.</p
- …
