TESTING FOR VARYING DISPERSION OF LONGITUDINAL BINOMIAL DATA IN NONLINEAR LOGISTIC MODELS WITH RANDOM EFFECTS

In this paper, it is discussed that two tests for varying dispersion of binomial data in the framework of nonlinear logistic models with random effects, which are widely used in analyzing longitudinal binomial data. One is the individual test and power calculation for varying dispersion through testing the randomness of cluster effects, which is extensions of Dean(1992) and Commenges et al (1994). The second test is the composite test for varying dispersion through simultaneously testing the randomness of cluster effects and the equality of random-effect means. The score test statistics are constructed and expressed in simple, easy to use, matrix formulas. The authors illustrate their test methods using the insecticide data (Giltinan, Capizzi & Malani (1988)).

A shield of defense:Developing ballistic composite panels with effective electromagnetic interference shielding absorption

The primary goal of this study is to develop cost-effective shield materials that offer effective protection against high-velocity ballistic impact and electromagnetic interference(EMI)shielding capabilities through absorption.Six fiber-reinforced epoxy composite panels,each with a different fabric material and stacking sequence,have been fabricated using a hand-layup vacuum bagging process.Two panels made of Kevlar and glass fibers,referred to as(K-NIJ)and(G-NIJ),have been tested according to the National Institute of Justice ballistic resistance protective materials test NIJ 0108.01 Standard-Level IIIA(9 mm×19 mm FMJ 124 g)test.Three panels,namely,a hybrid of Kevlar and glass(H-S),glass with ceramic particles(C-S),and glass with recycled rubber(R-S)have been impacted by the bullet at the center,while the fourth panel made of glass fiber(G-S)has been impacted at the side.EMI shielding properties have been measured in the X-band frequency range via the reflection-transmission method.Results indicate that four panels(K-NIJ,G-NIJ,H-S,and G-S)are capable of withstanding high-velocity impact by stopping the bullet from penetrating through the panels while maintaining their structural integrity.However,under such conditions,these panels may experience localized delamination with variable severity.The EMI measurements reveal that the highest absorptivity observed is 88% for the KNIJ panel at 10.8 GHz,while all panels maintain an average absorptivity above 65%.All panels act as a lossy medium with a peak absorptivity at different frequencies,with K-NIJ and H-S panels demonstrating the highest absorptivity.In summary,the study results in the development of a novel,costeffective,multifunctional glass fiber epoxy composite that combines ballistic and electromagnetic interference shielding properties.The material has been developed using a simple manufacturing method and exhibits remarkable ballistic protection that outperforms Kevlar in terms of shielding efficiency;no bullet penetration or back face signature is observed,and it also demonstrates high EMI shielding absorption.Overall,the materials developed show great promise for various applications,including the military and defense.

Highly efficient CO_(2) capture using 2-methylimidazole aqueous solution on laboratory and pilot-scale

To date,the primary industrial carbon capture approach is still absorption using aqueous solutions of alkanolamines.Here,to pursue a substitute for the amine-based approach to improve the CO_(2) capture efficiency and decrease the energy cost further,we report a new carbon capture approach using a 2-methylimidazole(mIm)aqueous solution.The properties and sorption behaviors of this approach have been experimentally investigated.The results show that the mIm solution has higher CO_(2) absorption capacity under relatively higher equilibrium pressure(>130 kPa)and lower desorption heat than the methyldiethanolamine solution.91.6%sorption capacity of mIm solution can be recovered at 353.15 K and 80 kPa.The selectivity for CO_(2)/N_(2) and CO_(2)/CH_(4) can reach an exceptional 7609 and 4324,respectively.Furthermore,the pilot-scale tests were also performed,and the results demonstrate that more than 98%of CO_(2) in the feed gas could be removed and cyclic absorption capacity can reach 1 mol·L^(-1).This work indicates that mIm is an excellent alternative to alkanolamines for carbon capture in the industry.

Damage degradation mechanism and macro-meso structural response of mudstone after water wetting

The predominant presence of weak interlayers primarily composed of mudstone renders them highly susceptible to a reduction in bearing capacity due to the water-rock weakening effect,significantly impacting the safety of open-pit mining operations.This study focuses on the weak mudstone layers within open-pit mine slopes.The mineral composition of mudstone and the microstructure evolution characteristics before and after water wetting were analyzed by X-ray diffraction(XRD)and scanning electron microscope(SEM).The meso-structure and parameter variation characteristics of mudstone interior space after water-rock interaction were quantified by computed tomography scanning test,and the damage variable characterization method was proposed.Additionally,according to the uniaxial compression test,the degradation characteristics of the macroscopic mechanical behavior of mudstone under different water wetting time were explored,and the elastic modulus and strength attenuation model of mudstone based on mesoscopic damage were established.Finally,building upon the macro-meso structural response characteristics of mudstone,an exploration of the failure characteristics and deterioration mechanism under the influence of water-rock interactions was undertaken.The results show that the water-rock interaction makes the internal defects of mudstone gradually develop and form a fracture network structure,which eventually leads to the deterioration of its macroscopic mechanical properties.The porosity,fractal dimension and damage characteristics of mudstone show an exponential trend with the increase of water wetting time.Moreover,the deterioration mechanism of mudstone after water wetting are postulated to encompass factors such as the hydrophilicity of mineral molecular structures,hydration stress and expansion effects on clay particles,as well as the spatial distribution of microcracks and the phenomenon of fracture adsorption.The outcomes of this research endeavor aim to provide certain reference value for further understanding the water-rock interaction and stability control of mudstone slope.

Amplitude and phase controlled absorption and dispersion of coherently driven five-level atom in double-band photonic crystal

The absorption–dispersion properties of a microwave-driven five-level atom embedded in an isotropic photonic bandgap(PBG) have been studied. Due to the singular density of modes(DOM) in the isotropic PBG and the dynamically coherence induced by the coupling fields, modified reservoir-induced transparency and quantum interference-induced transparency emerge simultaneously. Their interaction leads to ultra-narrow spectral structure. As a result of closed-loop configuration, these features can be manipulated by the amplitudes and relative phase of the coherently driven fields. The position and width of PBG also have an influence on the spectra. The theoretical studies can provide us with more efficient methods to control the atomic absorption–dispersion properties, which have applications in optical switching and slow light.

Comparison of absorption dispersion and optical bistability behaviors between open and closed four-level tripod atomic systems

In this paper we investigate the optical properties of an open four-level tripod atomic system driven by an elliptically polarized probe field and compare its properties with the corresponding closed system. Our results reveal that absorption,dispersion, group velocity, and optical bistability of the probe field can be manipulated by adjusting the phase difference between the two circularly polarized components of a single coherent field and cavity parameters, i.e., the atomic exit rate from cavity and atomic injection rates.

Absorption and dispersion control in a five-level M-type atomic system

We investigate the steady optical response of a coherently driven five-level M-type atomic system in three different situations. When all three coupling fields have the same zero detuning, we just find one deep transparency window accompanied by a steep normal dispersion in the probe absorption and dispersion spectra. When two coupling fields are detuned from the relevant transitions to the same extent, however, a second deep transparency window may be observed in the presence of a narrow absorption line of linewidth - 50 kHz. In this case, two single-photon far-detuned transitions can be replaced by a two-photon resonant transition, so the five-level M system in fact reduces into a four-level quasi-A system. Finally, we note that no deep transparency windows and no narrow absorption lines can be found when all three coupling fields have unequal detunings.

Controllable Absorption and Dispersion Properties of an RF-driven Five-Level Atom in a Double-Band Photonic-Band-Gap Material

驾驶五水平的原子在 photonic 晶体嵌入的无线电频率(RF ) 的探查吸收分散系列被考虑各向同性的双乐队 photonic-band-gap (PBG ) 水库调查。在使用的模型，分别地，二转变被上面、更低的乐队在如此的 PBG 材料联合，因此导致一些好奇的现象。数字模拟为光系列被执行。当一转变频率在乐队差距内，其它在差距外面时，它被发现那，在那里出现在吸收系列的三座山峰。然而，为案例，二转变频率躺着在内或在乐队差距外面，系列显示四吸收侧面。特别，在那里出现在系列的二座锋利的山峰当两转变频率在乐队内存在时，豁开。吸收性、散的反应上的驾驶 RF 的地的紧张和频率的影响在不同乐队边位置下面被分析。一个透明性窗口出现在吸收系列，这被发现并且被调整系统参数被分散侧面的一个很陡峭的变化伴随。这些结果证明系统的吸收分散性质强烈取决于导致 RF 的量干扰和 PBG 水库的状态(DOS ) 的密度。

Correlation between induced embryo toxicity and absorption dose of enriched uranium in testes

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Modeling on Residence Time Distribution in Subsurface Flow Constructed Wetlands by Multi Flow Dispersion Model

As an important design factor for constructed wetlands,hydraulic retention time and its distribution will affect the treatment performance.Instantaneously injected sodium chloride tracers were used to obtain residence time distributions of the lab scale subsurface flow constructed wetland.Considering the presence of trailing and multiple peaks of the tracer breakthrough curve,the multi flow dispersion model(MFDM)was used to fit the experimental tracer breakthrough curves.According to the residual sum of squares and comparison between the experimental values and simulated values of the tracer concentration,MFDM could fit the residence time distribution(RTD)curve satisfactorily,the results of which also reflected the layered structure of wetland cells,thus to give reference for application of MFDM to the same kind of subsurface flow constructed wetlands.

Effect of water absorption ratio on tensile strength of red sandstone and morphological analysis of fracture surfaces

Brazilian disc tests were undertaken on a number of red sandstone samples with different water absorption ratios.The tensile strength of the red sandstone decreases as the water absorption ratio increases.The fracture surfaces of failed red sandstone discs were scanned by Talysurf CLI 2000.With the aid of Talymap Gold software,based on ISO25178,a set of statistical parameters was obtained for the fracture surfaces.The maximum peak height(S_p),maximum pit height(S_v) and maximum height(S_z) of the fracture surfaces exhibited the same decreasing trend with increasing water absorption.Sa and Sku values for the fracture surfaces showed a downward trend as the water absorption ratio increased.The fractal dimensions of fracture surfaces were calculated and found to decrease as the water absorption ratio increased.Through analysis of PSD curves,the smallest dominant wavelength was observed to reflect the roughness of the fracture surfaces.Additionally,the results suggest that the roughness of fracture surfaces becomes small as the water absorption ratio increases.

Influence of Doppler-broadening on absorption-dispersion properties in a resonant coherent medium

We investigate the influence of Doppler broadening on absorption-dispersion properties in a four-level atomic system that can evolve from a normal dispersion to an anomalous dispersion. Our results show that the absorption-dispersion properties become strongly dependent on the propagation directions of the applied fields if Doppler broadening is taken into account. Especially, the switchover in the sign of the dispersion is still achievable even in the presence of Doppler broadening if properly arranging the propagation directions of the applied fields, which is in contrast with the otherwise behaviours in some other configurations.

Preparation and UV-light Absorption Property of Oleic Acid Surface Modified ZnO Nanoparticles

Syntheses of zince oxide（ZnO） nanoparticles by direct precipitation and surface modification with oleic acid were reported. ZnO nanoparticles were characterized via X-ray diffractometry（XRD）, transmission electron microscopy（TEM）, infrared spectroscopy（IR） and UV-Vis spectroscopy. The prepared ZnO nanoparticles were nearly spherical and highly crystalline with an average size of 29 nm. In addition, high UV-light absorption properties of oleic acid surface modified ZnO nanoparticles were successfully obtained for a dispersion of ZnO nanoparticles in ethanol.

TESTING FOR VARYING DISPERSION IN DISCRETE EXPONENTIAL FAMILY NONLINEAR MODELS

It is necessary to test for varying dispersion in generalized nonlinear models.Wei,et al(1998) developed a likelihood ratio test,a score test and their adjustments to test for varying dispersion in continuous exponential family nonlinear models.This type of problem in the framework of general discrete exponential family nonlinear models is discussed.Two types of varying dispersion,which are random coefficients model and random effects model,are proposed,and corresponding score test statistics are constructed and expressed in simple,easy to use,matrix formulas.

Effect of dynamic loading conditions on the dynamic performance of MP1 energy-absorbing rockbolts:Insight from laboratory drop test

Energy-absorbing rockbolts have been widely adopted in burst-prone excavation support, and their serviceability is closely related to the frequency and magnitude of seismic events. In this research, the splittube drop test with varying impact energy was conducted to reproduce the dynamic performance of MP1rockbolts under a wide range of seismic event magnitudes. The test results showed that the impact process could be subdivided into four distinct stages, i.e. mobilization, strain hardening, plastic flow(ductile), and rebound stage, of which strain hardening and plastic flow are the primary energy absorbing stages. As the impact energy per drop increases from 8.1 to 46.7 k J, the strain rate of the shank varies between 1.20 and 2.70 s^(-1), and the average impact load is between 240 and 270kN, which may be considered as constant. The MP1 rockbolt has a cumulative maximum energy absorption(CMEA) of 31.9–40.0 k J/m, with an average of 35.0 k J/m, and the elongation rate is 11.4%–14.7%, with an average of 12.7%, both of which are negatively correlated with the impact energy per drop. Regression analysis shows that energy absorption and shank elongation, as well as momentum input and impact duration,conform to the linear relationship. The complete dynamic capacity envelope of MP1 rockbolts is proposed, which reflects the dynamic bearing capacity, elongation, and distinct stages. This study is helpful to better understand the dynamic characteristics of energy-absorbing rockbolts and assist design engineers in robust reinforcement systems design to mitigate rockburst damage in seismically active underground excavations.

Retardation of Corrected QT Dispersion Recovery, Heart Rate Recovery and Increase of QT Dispersion in Patients with Pseudoexfoliative Syndrome;Are They Predictors of Malignant Arrythmias?

Background: In pseudoexfoliative syndrome (PEX), extraocular accumulation is associated with cardiovascular morbidity and mortality. The aim of this study was to investigate the effect of exercise test on corrected QT dispersion (QTcd) and QTcd recovery in PEX. Patients and Methods: A total of 37 patients diagnosed as PEX were included in the study. The control group consisted of 38 patients. The Electrocardiographies (ECG) were taken. The patients were subjected to an exercise test. Results: In the study group, baseline, peak and third minute recovery QTcd values were 41.35 ± 7.27 ms, 65.19 ± 7.83 ms, and 53.61 ± 6.45 ms, respectively. In the control group, baseline, peak and third minute recovery QTcd values were 29.92 ± 4.23 ms, 38.31 ± 4.22 ms and 28.76 ± 3.09 ms, respectively. There was statistically significant?difference between the baseline and peak QTcd values of the study group and?the control group (t = 8.34224/p 0.00001, t = 18.55079/p 0.00001, respectively). In addition, while there was a statistically significant?difference between the baseline QTcd and the third minute recovery QTcd in the study group, there was no statistically significant difference between the baseline QTcd value and the third minute recovery QTcd value in the control group as heart rate recovery (t = 8.388558/p 0.00001, t = 1.967315/p = 0.056668, respectively).?Conclusion: All of them were found to have a higher risk in terms of malignant ventricular arrhythmia in the study group, both at rest and with effort, in a statistically significant way compared to the control group.

Dispersion characteristics of clayey soils containing waste rubber particles

The rubber-containing waste materials have been widely used to improve the engineering properties of soils in recent years.Among others,granular rubbers are utilized in various ways to increase the bearing capacity and shear strength and to reduce the settlement and liquefaction potential of soils.The granular rubbers have many advantages such as temperature resistance,flexibility,tear-resistance,non-slip,and thermal and electrical insulation.This study presents the distribution characteristics of five different types of clayey soils with different engineering properties containing waste rubber particles(WRPs).On the other hand,determining and controlling the dispersion characteristics of clayey soils is two significant engineering problems.The study aims to solve these two remarkable and problematic issues in an eco-friendly and safe way.The role of WRP treatment in the investigation of soil dispersion behavior,which can cause dangerous problems such as piping,erosion,and dispersion,reflects the original and different perspectives of this study.Within this scope,geotechnical parameters of the clayey soils were determined.Subsequently,pinhole test,crumb test,double hydrometer test,and scanning electron microscopy(SEM)analysis were performed on the Na-activated bentonite,refined ball clay,Ukrainian kaolin,Avanos kaolin,and Afyon clay samples with different percentages of WRPs(0%,5%,10%,and 15%).Consequently,Avanos and Ukrainian kaolin clays gave the most limited response to the dispersion behavior with the addition of WRP.Also,WRP treatment on the ball clay and bentonite samples showed limited efficiency.Afyon clay,which was defined as dispersive by the three tests that determined its dispersion potential,showed 3 level changes in the pinhole tests and 2 level changes in the crumb tests,and gave the most effective results in terms of WRP efficiency.

Effects of 6-minute walk test on the QT dispersion in patients with congestive heart failure

Objective: To investigate the clinical value of QT dispersion (QTd) and the effects of 6-minute walk test (6-MWT) mimicking the patients' daily activities on QTd in patients with congestive heart failure (CHF).Methods: Twenty-eight CHF patients and 22 normal subjects participated these study, who all completed 6-MWT without developing severe arrhythmias.Before and after 6-MWT, standardized 12-lead surface ECGs were obtained to measure QTd and corrected QTd (QTcd).Results: Both before and after 6-MWT, the QTd and QTcd in CHF patients were longer than those in the controls (P<0.001), and QTd and QTcd after 6-MWT were significantly shorter than those before 6-MWT in CHF patients (P=0.007, and 0.018).There was no significant difference in the measurement in the control group.Conclusion: QTd and QTcd are longer in CHF patients than in normal subjects.Moderate exercise may improve the inhomogeneity of ventricular repolarization dispersion in CHF patients.

双壳体核电厂空间减震结构的竖向动力试验研究

为降低核电厂内安全壳的竖向加速度,提出了一种双壳体空间减震结构,基于该结构的力学特性建立了简化三质点三自由度动力模型,进一步给出了结构响应传递函数并进行了参数分析,明确了结构质量比、阻尼比和频率比对结构竖向地震响应的影响规律,完成了双壳体空间减震结构的缩尺振动台动力试验。结果表明:双壳体空间减震结构可减小内安全壳的竖向加速度,减震率为12.23%~27.84%。双壳体空间减震结构的振动台试验响应结果与理论计算值吻合较好,验证了所提出的双壳体空间减震结构简化模型的准确性以及双壳体空间减震系统的有效性。