1,371 research outputs found
Residual stress field of HIPed silicon nitride rolling elements
The residual stress field of HIPed Si3N4 rolling elements were studied. Two kinds of HIPed Si3N4 ball blanks self-finished at different nominal lapping loads ranging from 1.3 to 10.87 kgf/ball and four kinds of commercially finished 1/2 in (12.7 mm) HIPed Si3N4 balls before, during and after RCF tests were investigated. The experimental results showed that in the finishing process of HIPed Si3N4 rolling elements. the surface and subsurface compressive residual stress induced is proportional to the lapping load applied. There was initially a high compressive residual stress layer on the HIPed Si3N4 ball blanks and this layer is mostly removed during the finishing process. During the rolling contact fatigue process of HIPed Si3N4 rolling elements, the residual stresses on the rolling track will change dramatically as RCF proceeds
Exact Event Rates of Lepton Flavor Violating Processes in Supersymmetric SU(5) Model
Event rates of various lepton flavor violating processes in the minimal
supersymmetric SU(5) model are calculated, using exact formulas which include
Yukawa vertices of lepton-slepton-Higgsino. We find subtlety in evaluating
event rates due to partial cancellation between diagrams. This cancellation
typically reduces the event rates significantly, and the size of the reduction
strongly depends on superparticle mass spectrum.Comment: 11pages, 8 figures. Fig.5 where the mu-e conversion rates in nuclei
was shown was incorrect due to an error in our numerical computation.It is
replaced in this corrected version. All conclusions remain unchange
Limit on the Color-Triplet Higgs Mass in the Minimum Supersymmetric SU(5) Model
In the minimum supersymmetric SU(5) GUT, we derive the upper limit on the
mass of the color-triplet Higgs multiplets as \mhc\leq 2.4\times 10^{16}~\GEV
(90 \% C.L.) taking all possible corrections into account in a renormalization
group analysis. If the above upper limit is compared with a limit on \mhc
from the negative search for the proton decay; \mhc \geq 2.0\times
10^{16}~\GEV (in which effects of the larger top-quark mass are included), the
minimum supersymmetric SU(5) GUT is severely constrained
The role of cattle manure in enhancing on-farm productivity, macro- and micro-nutrient uptake, and profitability of maize in the Guinea savanna
An on-farm trial was conducted in the northern Guinea savanna of Nigeria, over a period of five years, with the objectives of quantifying the effects on maize of applying cattle manure in combination with synthetic fertilizer with regard to soil characteristics, yield, plant nutrition and profitability. Maize grain yield was significantly increased by the annual application of cattle manure, compared to maize receiving an equal amount of N through synthetic fertilizer, but only from the third year of the experiment. The application of manure resulted in higher soil Kjel N, Bray-I P and exchangeable K values, and an increased N utilization efficiency by maize, suggesting that yield-limiting factors other than N deficiencies were of lesser importance than in the treatment receiving sole inorganic fertilizer. Nutrients other than N applied via the manure, particularly P, K and/or B, may have contributed to the higher grain yields in treatments receiving manure. A partial budgeting analysis revealed that, over a 5-year period, investments in the application of manure, in combination with synthetic fertilizer, resulted in higher margins than the application of fertilizer alone. However, analyses of marginal rates of return of changes from low urea N to high urea N or additional manure applications suggested that it was more profitable to invest in additional urea than in organic manure in the first two years of the experiment. The results suggested that manure applications, even when applied at relatively high rates, did not serve as a quick fix to on-farm soil fertility problems, but over a longer period, manure applied in combination with synthetic fertilizers did provide a significant and profitable contribution to enhanced cereal production
A Solution for Little Hierarchy Problem and b --> s gamma
We show that all the parameters which destabilize the weak scale can be taken
around the weak scale in the MSSM without conflicting with the SM Higgs mass
bound set by LEP experiment. The essential point is that if the lightest
CP-even Higgs h in the MSSM has only a small coupling to Z boson, g_{ZZh}, LEP
cannot generate the Higgs sufficiently. In the scenario, the SM Higgs mass
bound constrains the mass of the heaviest CP-even Higgs H which has the SM like
g_{ZZH} coupling. However, it is easier to make the heaviest Higgs heavy by the
effect of off-diagonal elements of the mass matrix of the CP-even Higgs because
the larger eigenvalue of 2 times 2 matrix becomes larger by introducing
off-diagonal elements. Thus, the smaller stop masses can be consistent with the
LEP constraints. Moreover, the two excesses observed at LEP Higgs search can
naturally be explained as the signals of the MSSM Higgs h and H in this
scenario. One of the most interesting results in the scenario is that all the
Higgs in the MSSM have the weak scale masses. For example, the charged Higgs
mass should be around 130 GeV. This looks inconsistent with the lower bound
obtained by the b --> s gamma process as m_{H^\pm}>350GeV. However, we show
that the amplitude induced by the charged Higgs can naturally be compensated by
that of the chargino if we take the mass parameters by which the little
hierarchy problem can be solved. The point is that the both amplitudes have the
same order of magnitudes when all the fields in the both loops have the same
order of masses.Comment: 14 pages, 5 figures, input parameter slightly changed, figures
replaced, references correcte
Ï-Conjugated Macrocycles Bearing Angle-Strained Alkynes
Angleâstrained alkyneâcontaining Ïâconjugated macrocycles are attractive compounds both in functional materials chemistry and biochemistry. Their interesting reactivity as well as photophysical and supramolecular properties have been revealed in the past three decades. This review highlights the recent advances in angleâstrained alkyneâcontaining Ïâconjugated macrocycles, especially their synthetic methods, the bond angles of alkynes (â sp at CâĄCâC), and their functions. The theoretical and experimental research on cyclo[n]carbons and paraâcyclophynes consisting of ethynylenes and paraâphenylenes are mainly summarized. Related macrocycles bearing other linkers, such as orthoâphenylenes, metaâphenylenes, heteroaromatics, biphenyls, extended aromatics, are also overviewed. Bond angles of strained alkynes in Ïâconjugated macrocycles, which are generable, detectable, and isolable, are summarized at the end of this review
Neutrino mixing and large CP violation in B physics
We show that in see-saw models of neutrino mass a la SUSY SO(10), the
observed large mixing in atmospheric neutrinos naturally leads to large b-s
transitions. If the associated new CP phase turns out to be large, this SUSY
contributions can drastically affect the CP violation in some of the B decay
channels yielding the beta and gamma angles of the unitarity triangle. They can
even produce sizeable CP asymmetries in some decay modes which are not CP
violating in the standard model context. Hence the observed large neutrino
mixing makes observations of low energy SUSY effect in some CP violating decay
channels potentially promising in spite of the agreement between the Standard
Model and data in K and B physics so far.Comment: References adde
Baseline characteristics and enrichment results from the SONAR trial
Aim:
The SONAR trial uses an enrichment design based on the individual response to the selective endothelin receptor antagonist atrasentan on efficacy (the degree of the individual response in the urinary albuminâtoâcreatinine ratio [UACR]) and safety/tolerability (signs of sodium retention and acute increases in serum creatinine) to assess the effects of this agent on major renal outcomes. The patient population and enrichment results are described here.
Methods:
Patients with type 2 diabetes with an estimated glomerular filtration rate (eGFR) within 25 to 75âmL/min/1.73âm2 and UACR between 300 and 5000âmg/g were enrolled. After a runâin period, eligible patients received 0.75âmg/d of atrasentan for 6âweeks. A total of 2648 responder patients in whom UACR decreased by â„30% compared to baseline were enrolled, as were 1020 nonâresponders with a UACR decrease of <30%. Patients who experienced a weight gain of >3âkg and in whom brain natriuretic peptide exceeded â„300âpg/mL, or who experienced an increase in serum creatinine >20% (0.5âmg/dL), were not randomized.
Results:
Baseline characteristics were similar for atrasentan responders and nonâresponders. Upon entry to the study, median UACR was 802âmg/g in responders and 920âmg/g in nonâresponders. After 6âweeks of treatment with atrasentan, the UACR change in responders was â48.8% (95% CI, â49.8% to â47.9%) and in nonâresponders was â1.2% (95% CI, â6.4% to 3.9%). Changes in other renal risk markers were similar between responders and nonâresponders except for a marginally greater reduction in systolic blood pressure and eGFR in responders.
Conclusions:
The enrichment period has successfully identified a population with a profound UACR reduction without clinical signs of sodium retention in whom a large atrasentan effect on clinically important renal outcomes is possible. The SONAR trial aims to establish whether atrasentan confers renal protection
Neutrino-induced lepton flavor violation in gauge-mediated supersymmetry breaking
Gauge-mediated supersymmetry breaking is known to greatly suppress flavor
changing neutral current effects. However, we show that gauge mediation in the
context of leptogenesis implies potentially large lepton flavor violating
signals. If the heavy right-handed neutrinos that participate in leptogenesis
are lighter than the messenger scale of gauge mediation, they will induce
flavor off-diagonal masses to the sleptons which in turn can induce large
effects in mu to e gamma, tau to mu gamma, and mu-e conversion in nuclei. We
demonstrate this result and compute numerically the lepton-flavor violating
decay and conversion rates in scenarios of direct gauge mediation.Comment: 18 pages, 5 figure
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