712 research outputs found
Higher order mode circularly polarized two-layer rectangular dielectric resonator antenna
A two-layer higher order mode circularly polarized (CP)
rectangular dielectric resonator antenna (RDRA) is proposed at a
frequency range of 10 to 13GHz using a single-feed. The configuration
incorporates the DRA and a dielectric coat layer with respective dielectric
constants of 10 and 3.5. Utilizing the outer layer offers a number of
advantages such as wider impedance and CP bandwidths of âŒ21%, and
9.5%, respectively, as well as a high gain of ~11dBic. Close agreement has
been achieved between experimental and simulated results
Wideband millimeter-wave perforated hemispherical dielectric resonator antenna
This paper presents a novel wideband circularly polarized millimeter-wave (mmWave) hemispherical dielectric resonator antenna (HDRA). Two distinct configurations of alumina dielectric resonator antennas (DRAs) are investigated, each featuring a different coating: the first configuration incorporates a polyimide layer, while the second involves a perforated alumina. Both configurations demonstrate promising characteristics, including impedance and axial ratio (AR) bandwidths of 58% and 17.7%, respectively, alongside a maximum gain of 10 dBic at 28 GHz. Leveraging additive manufacturing technology, the HDRA with the perforated coating layer is fabricated, simplifying assembly and eliminating potential air gaps between layers, thereby enhancing the overall performance. This innovative approach yields a circularly polarized (CP) HDRA suitable for Beyond 5G (B5G) communication systems. Agreement between measurements and simulations validates the efficacy of the proposed design, affirming its potential in practical applications
Sampled-data sliding mode observer for robust fault reconstruction: A time-delay approach
A sliding mode observer in the presence of sampled output information and its application to robust fault reconstruction is studied. The observer is designed by using the delayed continuous-time representation of the sampled-data system, for which sufficient conditions are given in the form of linear matrix inequalities (LMIs) to guarantee the ultimate boundedness of the error dynamics. Though an ideal sliding motion cannot be achieved in the observer when the outputs are sampled, ultimately bounded solutions can be obtained provided the sampling frequency is fast enough. The bound on the solution is proportional to the sampling interval and the magnitude of the switching gain. The proposed observer design is applied to the problem of fault reconstruction under sampled outputs and system uncertainties. It is shown that actuator or sensor faults can be reconstructed reliably from the output error dynamics. An example of observer design for an inverted pendulum system is used to demonstrate the merit of the proposed methodology compared to existing sliding mode observer design approaches
Wideband millimeter-wave perforated cylindrical dielectric resonator antenna configuration
This article delves into the capabilities of 3D-printed millimeter-wave (mmWave) layered cylindrical dielectric resonator antennas (CDRAs). The proposed design yielded promising results, boasting a remarkable 53% impedance bandwidth spanning the frequency spectrum from 18 to 34 GHz. Furthermore, the axial ratio (AR) bandwidth achieved an impressive 17%, coupled with a maximum gain of 13.3 dBic. These notable results underscore the efficacy of the proposed design, positioning it as a viable solution for applications in Beyond 5G (B5G). A novel assembly technique was also investigated, employing additive manufacturing to seamlessly merge two layers with distinct dielectric constants into a singular layer. This innovative approach systematically eliminates the potential for air gaps between layers, enhancing the antennaâs overall performance. This approach exhibited potential, particularly in the performance of a millimeter-wave circularly polarized (CP) cylindrical DRA featuring a perforated coating layer. The synergy between measurements and simulations demonstrates a remarkable alignment, providing robust validation of the effectiveness of the proposed design
Influence of seed invigoration techniques on germination and seedling vigor of maize (Zea mays L.)
The objective of this study
was to assess the comparative efficiency of
different priming techniques on germination
and early seedling growth of maize
cultivars. Laboratory experiments were
conducted to examine the efficacy of
different seed invigoration treatments on
seed germination and vigor traits of three
maize hybrids, Pioneer 3025, Pioneer 70
and Baber at Agronomy research laboratory,
University of Agriculture, Peshawar,
Pakistan. The experiment was laid in
completely randomized design (CRD) and
was replicated thrice. The treatments
included control treatment (T1)
unsoaked/dry seed, (T2) hydropriming with
distilled water for 24 hrs, (T3) halo priming
treatments with NaCl (3% solution) for 24
hrs, (T4) osmopriming with PEG-6000 for
24 hrs and (T5), hormonal priming with GA3
for 24 hrs. The results showed that seed
invigoration treatment with gibberellic acid
(GA3) PEG-6000 and hydropriming with
distilled water for 24 hrs gave higher
germination, decreased days to 50%
germination, increased shoot length, root
length, seedling fresh and dry weight, as
compared to halo priming with NaCl and
control treatment. It is concluded that seed
invigoration with GA3, osmopriming with
PEG-6000 and hydropriming with distilled
water for 24 hrs serve as an appropriate
treatment for accelerating the emergence
and growth parameters of maize hybrid.
Pioneer 3025 showed its superiority over
other cultivars in all the studied parameters
Colo-Colonic Intussusception Caused by a Submucosal Lipoma: Case Report and Review of the Literature
Adult intussusception is a rare clinical presentation and often not considered clinically in the differential diagnosis of adult patients with vague abdominal complaints. A 44-year-old woman visited our emergency department with sudden onset of intermittent abdominal pain. Diagnostic imaging revealed an intussusception caused by a submucosal lipoma of the sigmoid. A laparotomy was performed and the diagnosis was proven by histological examination. Submucosal lipomas are usually asymptomatic but may cause bleeding, obstruction, intussusception, or abdominal pain and thus mimic a malignancy. Surgical excision is indicated for symptomatic cases
Effects of Large CP violating phases on g_{\m}-2 in MSSM
Effects of CP violation on the supersymmetric electro-weak correction to the
anomalous magnetic moment of the muon are investigated with the most general
allowed set of CP violating phases in MSSM. The analysis includes contributions
from the chargino and the neutralino exchanges to the muon anomaly. The
supersymmetric contributions depend only on specific combinations of CP phases.
The independent set of such phases is classified. We analyse the effects of the
phases under the EDM constraints and show that large CP violating phases can
drastically affect the magnitude of the supersymmetric electro-weak
contribution to and may even affect its overall sign.Comment: 26 pages Latex file including 4 figure
Yukawa structure, flavour and CP violation in Supergravity
The hierarchical structure of fermion masses and mixings strongly suggests an
underlying family symmetry. In supergravity any familon field spontaneously
breaking this symmetry necessarily acquires an F-term which contributes to the
soft trilinear couplings. We show, as a result, mu -> e gamma decay can receive
large contributions from this source at the level of current experimental
bounds and thus this channel may provide the first indication of supersymmetry
and a clue to the structure of the soft breaking sector. Using the mercury EDM
bounds we find strong bounds on the right handed down quark mixing angles that
are inconsistent with models relating them to neutrino mixing angles and favour
a near-symmetric form for the magnitude of the down quark mass matrix.Comment: Final version to appear in PRD. Improved discusion of several points,
updated references, typos correcte
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
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