564 research outputs found
Urbanization: Planting Forests in Pots
Taking plants from their original habitat and keeping them in pots is an illustrative example of manmade, power-oriented and unnatural habitation. Naturally, a plant cannot survive in a segregated environment of a pot. For this reason, diverse supportive activities such as watering, feeding or protecting must be planned. These supplying infrastructures create a great power for the caretaker over the life of the potted plant. Using the example of potted plants, this article tries to shed light on social and ecological problems of urbanization
Profession Vs Ethics
This article studies the process of professionalization in general and particularly in architecture and reviews the concept of professional ethics and the codes and documents related to it. The article investigates on the motivations of the conflicts between the documents of professional ethics with the ethical values by criticizing several codes of professional conducts produces by the main professional organizations in the field of architecture. The article proposes an ethical approach which can go beyond and above professions and their limited professional interests to be able to prevent the unethical professional conducts
Urban Cages and Domesticated Humans
In this article, the study assessed the domestication process of humankind within the frame of urbanization and power accumulation. Within this framework, by giving various examples from chicken farms. The study express the author\u27s opinions on the analogy of the “liberated human beings” in cities and the “free range” chickens in farms. It has also been tried to explain how a city acts as a human farm. Cities are governed by the ones holding power similar to the farms are ruled by farmers and humans during their history of civilization have lost their right of deciding on their lives and fates against this power as the domesticated animals in farms. It is necessary to give up these cities which are models of life organizations from the Old and the Middle Ages. Models of settlements which became even more inhumane as results of modernization and neoliberalization strategies. The study revealed that With the scientific and technologic improvements and the developments of in science and humanities, it is possible to easily replace the city model of communal life with a better one -The one in which people can be more free and happy and will give more life to the earth and contribute to the aliveness within it
Pacifying the Fermi-liquid: battling the devious fermion signs
The fermion sign problem is studied in the path integral formalism. The
standard picture of Fermi liquids is first critically analyzed, pointing out
some of its rather peculiar properties. The insightful work of Ceperley in
constructing fermionic path integrals in terms of constrained world-lines is
then reviewed. In this representation, the minus signs associated with
Fermi-Dirac statistics are self consistently translated into a geometrical
constraint structure (the {\em nodal hypersurface}) acting on an effective
bosonic dynamics. As an illustrative example we use this formalism to study
1+1-dimensional systems, where statistics are irrelevant, and hence the sign
problem can be circumvented. In this low-dimensional example, the structure of
the nodal constraints leads to a lucid picture of the entropic interaction
essential to one-dimensional physics. Working with the path integral in
momentum space, we then show that the Fermi gas can be understood by analogy to
a Mott insulator in a harmonic trap. Going back to real space, we discuss the
topological properties of the nodal cells, and suggest a new holographic
conjecture relating Fermi liquids in higher dimensions to soft-core bosons in
one dimension. We also discuss some possible connections between mixed
Bose/Fermi systems and supersymmetry.Comment: 28 pages, 5 figure
A Simple Method for Finding Optimal Paths of Hot and Cold Streams inside Shell and Tube Heat Exchangers to Reduce Pumping Cost in Heat Exchanger Network Problems
In this paper, a simple method is presented for the synthesis and retrofit of heat exchanger networks (HENs) by considering pressure drop as well as finding proper path of streams inside heat exchangers (HEs) to reduce the pumping cost of network. Generally, HEN problems lead to MINLP models which have convergence difficulties due to the existence of both continuous and integer variables. In this study, instead of solving these variables simultaneously, a combination of Genetic Algorithm (GA) with Quasi Linear Programming (QLP) and Integer Linear Programming (ILP) was used for solving the problem. GA was used to find optimal HENs structure and streams paths, whereas continuous variables were solved by QLP. For the retrofit of HENs, a modified ILP model was used. Results show that the proposed method has the ability to reduce the cost of
annual pumping due to considering optimal paths for streams in the HEs compared to the literature.
This work is licensed under a Creative Commons Attribution 4.0 International License
Arthroskopische Behandlung des femoroazetabulären Impingements
Zusammenfassung: Eine erst kürzlich etablierte, aber häufige Ätiologie der Hüftschmerzen beim jungen Erwachsenen ist das femoroazetabuläre Impingement (FAI), das eine leichte Form der frühzeitigen degenerativen Erkrankung des Hüftgelenks darstellt. Die klinischen Aspekte und diagnostischen Möglichkeiten sollen im Folgenden diskutiert und eine komplett arthroskopische Korrektur dieser Pathologie präsentiert werden. Mit dieser Technik können die azetabuläre Komponente ebenso wie die pathologischen Veränderungen am Femurkopf behandelt werden. Das schließt — falls notwendig — auch eine Labrumnaht mit ein. Neurologische Komplikationen durch lange Distraktionszeiten können durch die Anwendung einer invasiven Distraktionsmethode vermieden werden. Die Ergebnisse der arthroskopischen Behandlung sind mit denen der offenen chirurgischen Technik vergleichba
The Berry phase of dislocations in graphene and valley conserving decoherence
We demonstrate that dislocations in the graphene lattice give rise to
electron Berry phases equivalent to quantized values {0,1/3,-1/3} in units of
the flux quantum, but with an opposite sign for the two valleys. An elementary
scale consideration of a graphene Aharonov-Bohm ring equipped with valley
filters on both terminals, encircling a dislocation, says that in the regime
where the intervalley mean free path is large compared to the intravalley phase
coherence length, such that the valley quantum numbers can be regarded as
conserved on the relevant scale, the coherent valley-polarized currents
sensitive to the topological phases have to traverse the device many times
before both valleys contribute, and this is not possible at intermediate
temperatures where the latter length becomes of order of the device size, thus
leading to an apparent violation of the basic law of linear transport that
magnetoconductance is even in the applied flux. We discuss this discrepancy in
the Feynman path picture of dephasing, when addressing the transition from
quantum to classical dissipative transport. We also investigate this device in
the scattering matrix formalism, accounting for the effects of decoherence by
the Buttiker dephasing voltage probe type model which conserves the valleys,
where the magnetoconductance remains even in the flux, also when different
decoherence times are allowed for the individual, time reversal connected,
valleys.Comment: 14 pages, 7 figures; revised text, added figure, accepted for
publication by PR
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