Variations In C1 Research Articles

Litar Setara Dwi Jalur Antena Dwikutub Bersepadu untuk Aplikasi RFID

This paper presents dual band antenna by designing basic dipole antenna integrated with C-shaped patches structure for RFID applications. This C-shaped patch is inspired by E-shapes patch antenna that able to perform multiband frequency. The design of the equivalent circuit started with the fundamental circuit of impedance Zo and Z1 which functioned as a dipole antenna in single band. The parallel RLC circuit of impedance Z2 is added in the circuit as loaded patch has affected the resonating frequency. Variations of C1 and L1 on impedance Z1 effect a gap between the two resonance frequencies without changing the bandwidth by shifting the lower frequency. In addition, the variation of C2 and L2 on the impedance Z2 also affects the ratio between the two resonance frequencies but both frequencies are shifted and the bandwidth changes. Consequently, the dual band is presented at 0.915 GHz (UHF RFID) and 2.4 GHz (ISM RFID) by calculating the value of the resistance, inductance and capacitance. The data from electromagnetic simulation are compared with the data predicted by the antenna circuit modeling. The frequency sampled measurement data may be represented in the form of S-parameter in order to represent dependent data in a time domain simulator in P-SPICE software. The C-shaped design can be independently controlled to perform lower band and upper band by adjusting the width and length of the patch. The performance of the proposed antenna demonstrates the dual band antenna for RFID application with good agreements between measured and simulated results.

Regional variations in C1–C2 bone density on quantitated computed tomography and clinical implications

BackgroundOur elderly population is growing and the number of spine fractures in the elderly is also growing. The elderly population in general may be considered as poor surgical candidates experience a high rate of fractures at C1 and C2 compared with the general population. Nonoperative management of upper cervical fractures is not benign as there is a high nonunion rate for both C1 and C2 fractures in the elderly, and orthosis compliance is often suboptimal, or complicated by skin breakdown. The optimal technique for upper cervical stabilization in the elderly may be different than in younger populations as the bone quality is inferior in the elderly. The objective of this basic science study is to determine whether the bone mineral density (BMD) of C1 and C2 vary by region, and if this is a gender difference in this elderly age group. MethodsTwenty cadaveric spines from 45 to 83 years of age were used to obtain BMD using quantitated computed tomography (QCT). BMD was measured using a QCT. For C1, 8 regions were determined: anterior tubercle, bilateral anterior and medial lateral masses, bilateral posterior arches, and posterior tubercle. For C2, 7 regional BMDs were determined: top of odontoid, base of odontoid-body interface, mid body, bilateral lateral masses, anterior inferior body near the discs space, and the C2 spinous process. ResultsThe BMD was greatest at the C1 anterior tubercle (564.4±175.8 mg/cm3) and C1 posterior ring (420.8±110.2 mg/cm3), and least at the anterior and medial lateral masses (262.8±59.5 mg/cm3, 316.9±72.6 mg/cm3). At C2 QCT BMD was greatest at the top of the dens (400.6±107.9 mg/cm3) decreasing down through the odontoid-C2 body junction (267.8±103.5 mg/cm3) and least in the mid C2 body 249.1±68.8 mg/cm3). The posterior arch of C1 and the spinous process of C2 had higher BMD's 420.8±110.2 mg/cm3 and 284.1±93.0 mg/cm3, respectively. A high correlation was observed between the BMD at the interface of the dens-vertebral body with the vertebral body with a Pearson correlation coefficient of 0.86. The BMD of the top of dens was significantly higher (p<.05) than all the regions in C2. ConclusionsRegional and segmental BMD variations at C1 and C2 have clinical implications for surgical constructs in the elderly population. Given the higher BMDs of the C1 and C2 spinous process and posterior arches, consideration should be given to incorporate these areas using various C1–C2 wiring techniques. In the elderly, lateral masses particularly at C1 with lower BMD may result in potential screw loosening and nonunion in this age group. Old-school wiring techniques have a track record of efficacy and safety with less blood loss, reduced operative time, reduced X-ray exposure, and should be considered in the elderly as a primary stabilization technique or a belt-over suspenders approach based on regional variations in BMD in the elderly.

N-Hexane Hydrogenolysis Behavior of Alumina-Supported Palladium\u2013Platinum Alloys

The behavior of alumina-supported palladium-platinum catalysts in the reaction of n-hexane hydrogenolysis was analyzed. The monometallic Pt/Al2O3 catalyst showed much higher activity than the rest of catalysts. The relationship between the catalytic activity of Pd–Pt/Al2O3 catalysts and bulk Pd–Pt composition matched the accepted relation between the surface composition and bulk composition of Pd–Pt, confirming a high surface enrichment in palladium. A linear relation between the apparent activation energy and preexponential factor (compensation effect) suggests that the reaction mechanism is similar for all Pd–Pt catalysts. However, after very high temperature of catalyst reduction (at 600 °C), the behavior of monometallic Pd/Al2O3 catalyst exhibited a considerable departure from the compensation plot, and drastic variations in C1–C5 products distribution. Such big changes are rationalized by assuming the transformation of Pd/Al2O3 into Pd–Al alloy, occurring at very high temperature of reduction. Product distribution of n-hexane hydrogenolysis for Pt/Al2O3 differs from that of Pd/Al2O3, showing more internal bond splitting than a terminal demethylation. However, bimetallic Pd–Pt/Al2O3 catalysts showed even more ‘internal bond splitting’ character than the Pt/Al2O3. Reasons for this synergism and changes in the behavior of Pd/Al2O3 catalysts are analyzed in terms of an electronic interaction between metals and alumina support.Graphic

KVN observations reveal multiple γ-ray emission regions in 3C 84?

3C 84 (NGC 1275) is a well-studied mis-aligned Active Galactic Nucleus (AGN), which has been active in Gamma rays since at least 2008. We have monitored the source at four wavelengths (14 mm, 7 mm, 3 mm and 2 mm) using the Korean VLBI network (KVN) since 2013 as part of the interferometric monitoring of $\gamma$-ray bright AGN (iMOGABA) program. 3C 84 exhibits bright radio emission both near the central supermassive black hole (SMBH) feature known as C1 and from a moving feature located to the south known as C3. Other facilities have also detected these short-term variations above a slowly rising trend at shorter wavelengths, such as in Gamma ray and 1 mm total intensity light-curves. We find that the variations in the $\gamma$ rays and 1 mm total intensity light-curves are correlated, with the $\gamma$ rays leading and lagging the radio emission. Analysis of the 2 mm KVN data shows that both the Gamma rays and 1 mm total intensity short-term variations are better correlated with the SMBH region than C3, likely placing the short-term variations in C1. We interpret the emission as being due to the random alignment of spatially separated emission regions. We place the slowly rising trend in C3, consistent with previous results. Additionally, we report that since mid-2015, a large mm-wave radio flare has been occurring in C3, with a large Gamma ray flare coincident with the onset of this flare at all radio wavelengths.

Parametric Investigation of Mooney-Rivlin Material Constants on Silicone Biocomposite

Hyperelastic materials are unique materials that have high tendency to stretch and its highly non-linear behaviour is commonly investigated using hyperelastic constitutive models. The aim of this paper is to investigate the sensitivity of Mooney-Rivlin material constants; C1 and C2 values in order to observe the behavior and pattern of the stress-stretch graph for silicone-kenaf composite. There were no previous studies done in regards to assess the mechanical behaviour of the stress-stretch curve for silicone-kenaf biocomposite by varying the Mooney-Rivlin material constants. The material constant, C1 and C2 are varied into few cases and the patterns of stress-stretch curves are studied. It was found that variations of C1 and C2 material constants could contribute differently on the mechanical properties of silicone-kenaf composite. Thus, the results and findings of this study could be further enhanced by future study to gain deeper understanding on the hyperelastic materials behaviour and Mooney-Rivlin hyperelastic constitutive model.

A universal multifractal description applied to precipitation patterns of the Ebro River Basin, Spain

Water supplies in the Ebro River Basin are increasingly stressed, especially during the summer season. The year-to-year fluctuations in rainfall over this area exert vital influence on the regional hydrology, agriculture and several related industries in the region. Repeated anomalous rainfall in recent decades has had a devastating impact on this region, both socially and economically. We characterised the change in the rainfall variability pattern in the Ebro River Basin using universal multifractal (UM) analysis, which estimates the concentration of the data around the precipitation average (C1, codimension average), the degree of multiscaling behaviour in time (α index) and the maximum probable singularity in the rainfall distribution (γs). Fourteen meteorological stations were selected based on the length of rainfall series and the climatic classification to obtain a representative untreated data set from the river basin. Daily rainfall series from 1957 to 2002 were obtained from each meteorological station and subdivided (1957–1980 and 1981–2002) to analyse the difference between the 2 periods. The general scenario observed in this study, through the UM parameters, can be summarised as follows: the range of variation of precipitation amounts was spatially more homogenous in 1980–2002 than in 1957–1979; at the same time, there is higher frequency of dry periods at different scales in 1980–2002; and in almost all of the stations, the range of precipitation over the years has been decreasing at a lower rate than the rainfall average. We then analysed the evolution of the UM parameters from 1957 to 2002. Continuous variations in C1 and α were found for 2 of the stations, indicating that a precipitation regime change has begun in the last few decades and should be considered in the agricultural development of the region.

Abundances of RGB stars in NGC 6752

Abundances of O, Fe, Al, Mg, Na and Li determined from high-resolution and high signal{to{noise spectra of 21 red giant branch (RGB) stars in the globular cluster NGC 6752 are presented. We demonstrate that the Stromgren c1 index correlates extremely well with the measured NH, CH and CN indices and that variations in c1 are due to dierences in UV NH band strengths. As shown by Grundahl et al. (2002), the RGB stars in all 20 globular clusters surveyed possess large star-to-star variations in their c1 index, which we interpret as signicant inhomogeneities in N abundances. The well known relations among O and Na and Mg and Al as well as with CN, CH, and NH are also present in these stars, some of which are fainter than the RGB bump. We nd that the Li (6708 A) equivalent width becomes too small to be measured as the luminosity of the stars increase above the luminosity of the RGB bump. Taken together, these data enforce the results of Gratton et al. (2001) for turno and sub{giant branch stars, and suggest that in this cluster the abundance correlations observed among the brighter giants are in place prior to appreciable RGB ascent and likely due to previous generation(s) of stars, rather than due to mixing in the observed stars.

Are C1 chondrites chemically fractionated? a trace element study

Six C1 chondrite samples and a C2 xenolith from the Plainview H5 chondrite were analyzed by radiochemical neutron activation for the elements Ag, Au, Bi, Br, Cd, Ce, Cs, Eu, Ge, In, Ir, Lu, Nd, Ni, Os, Pd, Pt, Rb, Re, Sb, Se, Sn, Tb, Te, Tl, Yb, and Zn. The data were combined with 9 earlier analyses from this laboratory and examined for evidence of chemical fractionation in C1 chondrites. A number of elements (Br, Rb, Cs, Au, Re, Os, Ni, Pd, Sb, Bi, In, Te) show small but correlated variations. Those of the first 8 probably reflect hydrothermal alteration in the meteorite parent body, whereas those of Sb, Bi, In, and Te may at least in part involve nebular processes. Br and Au show systematic abundance differences from meteorite to meteorite, which suggests hydrothermal transport on a kilometer scale. The remaining elements vary from sample to sample, suggesting transport on a centimeter scale. There is no conclusive evidence for nebular fractionation affecting C1 's. Though C1 chondrites have lower Zr Hf and Ir Re ratios than do other chondrite classes, these ratios vary in other classes, suggesting that those classes rather than C1's are fractionated. Three fractionation-prone REE—Ce, Eu, and Yb have essentially the same relative abundances in C1's and all other chondrite classes, and hence apparently are not fractionated in C1's. We did not confirm the large Tb and Yb variations in C1's reported by other workers. We present revised mean C1 abundances for 35 elements, based on the new data and a critical selection of literature data. Changes are generally less than 10%, except for Br, Rb, Ag, Sb, Te, Au, and the REE. The Plainview C2 xenolith has normal trace element abundances, except for 3 elements falling appreciably above the C2 range: Rb, Cs, and Bi. Hydrothermal alteration may be the reason for all 3, though nebular fractionation remains a possibility for Bi.