199 research outputs found
Increasing the Seismic Resistance of Wood-frame Buildings by Applying PU Foam as Thermal Insulation
Wood-frame buildings are very common in regions that are exposed to earthquakes. Most of residential buildings are constructed using this technology; therefore, the seismic resistance of them is really essential in order to prevent human losses and structural damage. The aim of the present article is to show the results of the detailed numerical FEM analysis focused on the seismic behaviour of the wood-frame house with different in-wall insulation materials. The results of the study clearly indicate that using polyurethane (PU) foam instead of mineral wool leads to the increase in the rigidity of the structure and, therefore, to the substantial reduction in the structural response under different seismic excitations. The results also show that, generally speaking, the level of reduction in the displacement response increases with the increase in the magnitude of the earthquake, which even furthermore benefits the application of PU foam as an insulation material. It has also been concluded that the method of using PU foam can be successfully applied not only in the newly constructed wood-frame houses but also in existing ones since replacing the mineral wool with PU foam is relatively easy and not so much expensive
Quantized shift response in multi-gap topological phases
We show that certain 3D multi-gap topological insulators can host quantized
shift photoconductivities due to bulk invariants that are defined under reality
conditions imposed by additional symmetries. We recast the quantization in
terms of the integrated torsion tensor and the non-Abelian Berry connection
constituting Chern-Simons forms. Physically, we recognize that the topological
quantization emerges purely from virtual transitions contributing to the
optical response. Our findings provide another quantized electromagnetic DC
response due to the non-trivial band topology, beyond the quantum anomalous
Hall effect of Chern insulators and quantized circular photogalvanic effect
found in Weyl semimetals.Comment: 7+7 pages; 3+1 figure
PadSteg: Introducing Inter-Protocol Steganography
Hiding information in network traffic may lead to leakage of confidential
information. In this paper we introduce a new steganographic system: the
PadSteg (Padding Steganography). To authors' best knowledge it is the first
information hiding solution which represents inter-protocol steganography i.e.
usage of relation between two or more protocols from the TCP/IP stack to enable
secret communication. PadSteg utilizes ARP and TCP protocols together with an
Etherleak vulnerability (improper Ethernet frame padding) to facilitate secret
communication for hidden groups in LANs (Local Area Networks). Basing on real
network traces we confirm that PadSteg is feasible in today's networks and we
estimate what steganographic bandwidth is achievable while limiting the chance
of disclosure. We also point at possible countermeasures against PadSteg.Comment: 9 pages, 12 figures, 5 table
Numerical Model of Directional Radiation Pattern Based on Primary Antenna Parameters
The new numerical model of directional radiation pattern, in which part of energy is emitted in side and back lobs, has been presented in this paper. The model input values are determined on the base of primary parameters that can be read from the datasheet of used antennas. The special software tool NmAntPat has been elaborated to carry out the described task. The elaborated model, program and output files can be easily implemented into an analysis of radio wave propagation phenomenon in any algorithms and numerical calculations. The comparison of the graphical plots that have been obtained on the base of measurements, producers’ data specification notes and modelling results confirms the model correctness
On the need for methodocentrism in music teachers training system
The main idea of this paper, dedicated to Professor Andrzej Rakowski, is to emphasize that the pedagogy concentrated around the school curriculum and school subjects (eg. Music) has become more and more outdated. More useful seems to be a pedagogy oriented towards the so-called Great Author Concepts (Methods) of Music Education, eg. Dalcroze, Orff, Kodaly, Gordon and others. The author of the report provides a justification for his opinion, as well as specifying its purpose and the conditions under which it was formed. Primarily, the proposed approach involves combining the universality of the Methods with the individual preferences of both the teachers (representing the Method) and the students, providing the possibility of choice. The author sees the special value of that point of view in the integrative character of these Methods - combining an active and creative approach to music with the students’ perceptual and intellectual development. The report also highlights the requirement for a high level of teacher competence in the use of all the methods. Taking into the consideration all of the above (discussed in more detail in this report), the author puts forward a proposal for the reform of the system of training music teachers. According to the author, the system ought to be founded on the Methods (e.g. on one of them, particularly where the Concept/Method is already well developed)
The role of postoperative chemotherapy in patients who undergoing surgery following chemoradiotherapy of initially unresectable rectal cancer
Introduction. Preoperative chemoradiotherapy (preCRT) improves local control of rectal cancer and such is partiÂcularly merited for treating locoregionally advanced tumors. Nevertheless, the role of postoperative chemotherapy (postCT) in such patients is currently disputed. Materials. Subjects were 75 patients with unresectable cT3–4 and/or N+ tumors who underwent radical surgery following preCRT between January 2003 and December 2012 at the Oncology Centre in Bydgoszcz. PostCT was subsequently used in 32 (43%) of these patients. Results. There were 20 abdominoperineal resections (APR), 50 anterior resections (AR) and 5 Hartmann’s procedures (HART) performed in the patient group, where respectively 30%, 46% and 60%, received systemic treatment. Based on postoperative histopathological assessment, disease staging was assigned as follows: stage III for 32 (43%), patientÂs,stage II for 22 (29%) and stage I for 15 (20%). Pathologic complete pathological response (pCR) was seen in 6 cases (8%). In the postCT+ group, disease stage III was observed in 13 (41%) patients. A three-year survival was observed in 43 patients; 25 (58%) and 18 (56%) of patients respectively undergoing either postCT– or postCT+. A five-year survival was noted in 26 patients; 19 (44%) and 7 (22%) in both groups, respectively. Conclusion. Together with the most recent reports, our study demonstrates that postoperative chemotherapy has no significant effect on the outcomes of oncological treatment in those patients having undergone preoperative chemoradiotherapy for locoregionally advanced rectal cancer
Determination of the material relative permittivity in the UHF band by using T and modified ring resonators
The complete methodology of designing T- and modified ring resonators in the UHF band are presented in the paper. On the basis of proposed algorithms, the dedicated software tool has been elaborated in order to determine material parameters of contemporary substrates. The program is implemented in the Mathcad environment and it includes the base of information on known materials used in electronic products. Also, test sample series for selected substrate materials (IS680, FR408, I-SPEED PCB ISOLA and A6-S LTCC FERRO) and operating frequencies from 1 GHz to 3 GHz are analyzed in details. The special test stand with a vector network analyzer has been applied in experiments. The obtained data of relative permittivity measurements and model calculations are described, discussed and concluded
Disorder-induced topological quantum phase transitions in Euler semimetals
We study the effect of disorder in systems having a non-trivial Euler class.
As these recently proposed multi-gap topological phases come about by braiding
non-Abelian charged band nodes residing between different bands to induce
stable pairs within isolated band subspaces, novel properties that include a
finite critical phase under the debraiding to a metal rather than a transition
point and a modified stability may be expected when the disorder preserves the
underlying or symmetry on average. Employing
elaborate numerical computations, we verify the robustness of associated
topology by evaluating the changes in the average densities of states and
conductivities for different types of disorders. Upon performing a scaling
analysis around the corresponding quantum critical points we retrieve a
universality for the localization length exponent of for
Euler-protected phases, relating to 2D percolation models. We generically find
that quenched disorder drives Euler semimetals into critical metallic phases.
Finally, we show that magnetic disorder can also induce topological transitions
to quantum anomalous Hall plaquettes with local Chern numbers determined by the
initial value of the Euler invariant.Comment: 6+7 pages, 4+6 figure
- …