24 research outputs found
Multiple Criteria Evaluation of Assembling Buildings from Steel Frame Structures
Steel frame structures are often used in the construction of public and industrial buildings. They are used for all types of slope roofs; walls of newly built public and industrial buildings; load bearing structures; and roofs of renovated buildings. The process of assembling buildings from steel frame structures should be analysed as an integrated process influenced by factors such as construction materials and machinery used, the qualification level of construction workers, complexity of work, and available finance. It is necessary to find a rational technological design solution for assembling buildings from steel frame structures by conducting a multiple criteria analysis. The analysis provides a possibility to evaluate the engineering considerations and find unequivocal solutions. The rational alternative of a complex process of assembling buildings from steel frame structures was found through multiple criteria analysis and multiple criteria evaluation. In multiple criteria, evaluation of technological solutions for assembling buildings from steel frame structures by pairwise comparison method the criteria by significance are distributed as follows: durability is the most important criterion in the evaluation of alternatives; the price of a part of assembly process; construction workers’ qualification level (category); mechanisation level of a part of assembling process; and complexity of assembling work are less important criteria
Technical-Economic Research for Passive Buildings
The Energy Performance of Buildings Directive (EPBD) 61 requires all new public buildings to become near-zero-energy buildings by 2019 which will be extended to all new buildings by 2021. This concept involves sustainable, high-quality, valuable, healthy and durable construction. Foundation, walls and roofs are the most essential elements of a house. The type of foundation for a private house is selected considering many factors. The article examines technological and structural solutions for passive building foundation, walls and roofs. The technical-economic comparison of the main structures of a passive house revealed that it is cheaper to install an adequately designed concrete slab foundation than to build strip or pile foundation and the floor separately. Timber stud walls are the cheapest wall option for a passive house and 45–51% cheaper than other options. The comparison of roofs and ceilings showed that insulation of the ceiling is 25% more efficient than insulation of the roof. The comparison of the main envelope element efficiency by multiple-criteria evaluation methods showed that it is economically feasible to install concrete slab on ground foundation, stud walls with sheet cladding and a pitched roof with insulated ceiling
TRIM Simulations Tool for Stopping Fraction in Hydrostatic Pressure Cells
For quantum systems or materials, a common procedure for probing their
behaviour is to tune electronic/magnetic properties using external parameters,
e.g. temperature, magnetic field or pressure. Pressure application as an
external stimuli is a widely used tool, where the sample in question is
inserted into a pressure cell providing a hydrostatic pressure condition. Such
device causes some practical problems when using in Muon Spin
Rotation/Relaxation (SR) experiments as a large proportion of the muons
will be implanted in the pressure cell rather than in the sample, resulting in
a higher background signal. This issue gets further amplified when the
temperature dependent response from the sample is much smaller than that of the
pressure cell,which may cause the sample response to be lost in the background
and cause difficulties in aligning the sample within the beam. To tackle this
issue, we have used pySRIM to construct a practical and helpful simulation tool
for calculating muon stopping fractions, specifically for the pressure cell
setup at the E1 beamline using the GPD spectrometer at the Paul Scherrer
Institute, with the use of TRIM simulations. The program is used to estimate
the number of muon stopping in both the sample and the pressure cell at a given
momentum. The simulation tool is programmed into a GUI, making it accessible to
user to approximate prior to their experiments at GPD what fractions will
belong to the sample and the pressure cell in their fitting procedure.Comment: 8 Pages, 3 Figures, Conference proceedings for 15th international
conference on muon spin rotation, relaxation and resonanc
Magnetic nature of wolframite MgReO
Rhenium oxides belonging to the family ReO where is a metal
cation, exhibit interesting electronic and magnetic properties. In this study
we have utilized the muon spin rotation/relaxation (SR) technique to
study the magnetic properties of the MgReO compound. To the best of our
knowledge, this is the first investigation reported on this interesting
material, that is stabilized in a wolframite crystal structure using a special
high-pressure synthesis technique. Bulk magnetic studies show the onset of an
antiferromagnetic (AF) long range order, or a possible singlet spin state at
~K, with a subtle second high-temperature transition at
~K. Both transitions are also confirmed by heat capacity
() measurements. From our SR measurements, it is clear that the
sample enters an AF order below ~K. We find no
evidence of magnetic signal above , which indicates that is likely linked to a structural transition. Further, via sensitive zero
field (ZF) SR measurements we find evidence of a spin reorientation at
~K. This points towards a transition from a collinear AF
into a canted AF order at low temperature, which is proposed to be driven by
competing magnetic interactions
Magnetic Properties of Multifunctional LiFePO under Hydrostatic Pressure
LiFePO (LFPO) is an archetypical and well-known cathode material for
rechargeable Li-ion batteries. However, its quasi-one-dimensional (Q1D)
structure along with the Fe ions, LFPO also displays interesting
low-temperature magnetic properties. Our team has previously utilized the muon
spin rotation (SR) technique to investigate both magnetic spin order as
well as Li-ion diffusion in LFPO. In this initial study we extend our
investigation and make use of high-pressure SR to investigate effects on
the low- magnetic order. Contrary to theoretical predictions we find that
the magnetic ordering temperature as well as the ordered magnetic moment
increase at high pressure (compressive strain).Comment: 8 pages, 6 figures, submitted as a part of the International
Conference on Muon Spin Rotation, Relaxation and Resonance 2022. Accepted Dec
202
Anomalous Shubnikov-de Haas effect and observation of the Bloch-Gr\"uneisen temperature in the Dirac semimetal ZrTe5
Appearance of quantum oscillations (QO) in both thermodynamic and transport
properties of metals at low temperatures is the most striking experimental
consequence of the existence of a Fermi surface (FS). The frequency of these
oscillations and the temperature dependence of their amplitude provides
essential information about the FS topology and fermionic quasiparticle
properties. Here, we report the observation of an anomalous suppression of the
QO amplitude seen in resistivity (Shubnikov de-Haas effect) at sub-kelvin
temperatures in ZrTe5 samples with a single small FS sheet comprising less than
5% of the first Brillouin zone. By comparing these results with measurements of
the magneto-acoustic QO and the recovery of the usual Lifshitz-Kosevich
behavior of the Shubnikov de-Haas (SdH) effect in ZrTe samples with a
multi-sheet FS, we show that the suppression of the SdH effect originates from
a decoupling of the electron liquid from the lattice. On crossing the so-called
Bloch-Gr\"uneisen temperature, T, electron-phonon scattering becomes
strongly suppressed and in the absence of Umklapp scattering the electronic
liquid regains Galilean invariance. In addition, we show, using a combination
of zero-field electrical conductivity and ultrasonic-absorption measurements,
that entering this regime leads to an abrupt increase of electronic viscosity