The method of separation for evolutionary spectral density estimation of multi-variate and multi-dimensional non-stationary stochastic processes

The method of separation can be used as a non-parametric estimation technique, especially suitable for evolutionary spectral density functions of uniformly modulated and strongly narrow-band stochastic processes. The paper at hand provides a consistent derivation of method of separation based spectrum estimation for the general multi-variate and multi-dimensional case. The validity of the method is demonstrated by benchmark tests with uniformly modulated spectra, for which convergence to the analytical solution is demonstrated. The key advantage of the method of separation is the minimization of spectral dispersion due to optimum time- or space–frequency localization. This is illustrated by the calibration of multi-dimensional and multi-variate geometric imperfection models from strongly narrow-band measurements in I-beams and cylindrical shells. Finally, the application of the method of separation based estimates for the stochastic buckling analysis of the example structures is briefly discussed.     

Can Our Group Survive? An Investigation of the Evolution of Mixed‐Mode Groups

Applying an ecological and evolutionary perspective, this study examines the evolution and the sustainability of “mixed‐mode groups,” a type of voluntary association created and organized online to interact physically in geographically defined ways. Meetup.com is a website that facilitates the creation and coordination of mixed‐mode groups. Analysis of interviews with 34 Meetup group organizers and a longitudinal analysis of 100 randomly selected Meetup groups revealed the evolutionary processes at the group and population level, respectively. Specifically, the ecological factor of population density, the demographic factor of group age, the group's profit orientation, experience of leadership change and shared leadership, and external ties played decisive roles in predicting group survival. Implications of the findings for theoretical and practical contributions are discussed.     

浇筑式钢桥面铺装层推挤变形病害机理分析

以贵州省北盘江大桥钢桥面铺装层推挤变形病害为研究背景,采用凝胶渗透色谱法(GPC)和傅里叶变换红外光谱法(FTIR),从沥青分子尺度分析钢桥面铺装产生推挤变形的原因。分析结果表明:沥青老化并不是造成钢桥面铺装层推挤变形的主要原因;从现场调查可知,第2层粘层粘结能力的降低是造成钢桥面铺装层推挤变形病害的次要原因;通过级配分析发现,造成钢桥面铺装层推挤变形的主要原因是浇筑式沥青混合料(GA)级配偏细以及GA中集料颗粒的棱角性较差所致。     

Growth and characterization of 4-methyl benzene sulfonamide single crystals

Single crystals of 4-methyl benzene sulfonamide (4MBS) were successfully grown from aqueous solution by low temperature solution growth technique. The grown crystal was characterized by single crystal XRD and powder XRD methods to obtain the lattice parameters and the diffraction planes of the crystal. UV–vis–NIR absorption spectrum was used to measure the range of optical transmittance and optical band gap energy. The optical transmission range was measured as 250–1200 nm. FTIR spectral studies were carried out to identify the presence of functional groups in the grown crystal. The thermal behavior of the crystal was investigated from thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC) study. The absence of SHG was noticed by Kurtz and Perry powder technique. The third order NLO behavior of the material was confirmed by measuring the nonlinear optical properties using Z-scan technique and it was found that the crystal is capable of exhibiting saturation absorption and self-defocusing performance.     

Benchmark Experiment on Vanadium with D-T Neutrons and Validation of Evaluated Nuclear Data Libraries by Analysis of the Experiment

A neutronics benchmark experiment on vanadium, which is a low activation fusion reactor material, was conducted by using the D-T neutron source facility of FNS/JAERI. Neutron spectra, dosimetry reaction rates, γ-ray spectra and γ-ray heating rates were measured in a vanadium experimental assembly. Benchmark tests for four evaluated nuclear data files were performed by analyzing the experiment. As a result, the following problems were pointed out in view of accuracy of fusion reactor designs. (1) JENDL-FF and JENDL-3.2: Total cross section should be reexamined especially at ～2keV. (2) ENDF/B-VI: Double differential cross sections for 14 MeV neutrons should be revised because of the isotropic angular distribution for continuum neutron emission. Gamma-ray production cross sections are too small and discrete γ-ray peaks are not represented clearly. (3) EFF-3: Gamma-ray production cross sections are too large.     

Validation of mid-infrared spectrometry in milk for predicting body energy status in Holstein-Friesian cows

Cow energy balance is known to be associated with cow health and fertility; therefore, routine access to data on energy balance can be useful in both management and breeding decisions to improve cow performance. The objective of this study was to determine if individual cow milk mid-infrared spectra (MIR) could be useful to predict cow energy balance across contrasting production systems. Direct energy balance was calculated as the differential between energy intake and energy output in milk and maintenance (maintenance was predicted using body weight). Body energy content was calculated from (change in) body weight and body condition score. Following editing, 2,992 morning, 2,742 midday, and 2,989 evening milk MIR records from 564 lactations on 337 Scottish cows, managed in a confinement system on 1 of 2 diets, were available. An additional 844 morning and 820 evening milk spectral records from 338 lactations on 244 Irish cows offered a predominantly grazed grass diet were also available. Equations were developed to predict body energy status using the milk spectral data and milk yield as predictor variables. Several different approaches were used to test the robustness of the equations calibrated in one data set and validated in another. The analyses clearly showed that the variation in the validation data set must be represented in the calibration data set. The accuracy (i.e., square root of the coefficient of multiple determinations) of predicting, from MIR, direct energy balance, body energy content, and energy intake was 0.47 to 0.69, 0.51 to 0.56, and 0.76 to 0.80, respectively. This highlights the ability of milk MIR to predict body energy balance, energy content, and energy intake with reasonable accuracy. Very high accuracy, however, was not expected, given the likely random errors in the calculation of these energy status traits using field data.     

Triaxiality at crack tip for combined Lankford's coefficient and degree of anisotropy subjected to mixed-mode (I/II) fracture

Structural parts used in boilers, turbines, ships, and many household purposes are manufactured through sheet metal forming processes. During manufacturing, the micro structure of the material is deformed and micro cracks along with anisotropic properties get induced. Present research deals with a thin sheet metal plate containing a central crack subjected to mixed mode (I+II) loading. With special reference to Lankford's coefficient and degree of anisotropy, the effect of anisotropic triaxiality on crack initiation angle has been investigated. The result reveals the combinations of Lankford's coefficient and degree of anisotropy for which crack initiation angle do not change.     

Effect of pasture versus indoor feeding systems on quality characteristics,nutritional composition,and sensory and volatile properties of full-fat Cheddar cheese

The purpose of this study was to investigate the effects of pasture-based versus indoor total mixed ration (TMR) feeding systems on the chemical composition, quality characteristics, and sensory properties of full-fat Cheddar cheeses. Fifty-four multiparous and primiparous Friesian cows were divided into 3 groups (n = 18) for an entire lactation. Group 1 was housed indoors and fed a TMR diet of grass silage, maize silage, and concentrates; group 2 was maintained outdoors on perennial ryegrass only pasture (GRS); and group 3 was maintained outdoors on perennial ryegrass/white clover pasture (CLV). Full-fat Cheddar cheeses were manufactured in triplicate at pilot scale from each feeding system in September 2015 and were examined over a 270-d ripening period at 8°C. Pasture-derived feeding systems were shown to produce Cheddar cheeses yellower in color than that of TMR, which was positively correlated with increased cheese β-carotene content. Feeding system had a significant effect on the fatty acid composition of the cheeses. The nutritional composition of Cheddar cheese was improved through pasture-based feeding systems, with significantly lower thrombogenicity index scores and a greater than 2-fold increase in the concentration of vaccenic acid and the bioactive conjugated linoleic acid C18:2 cis-9,trans-11, whereas TMR-derived cheeses had significantly higher palmitic acid content. Fatty acid profiling of cheeses coupled with multivariate analysis showed clear separation of Cheddar cheeses derived from pasture-based diets (GRS or CLV) from that of a TMR system. Such alterations in the fatty acid profile resulted in pasture-derived cheeses having reduced hardness scores at room temperature. Feeding system and ripening time had a significant effect on the volatile profile of the Cheddar cheeses. Pasture-derived Cheddar cheeses had significantly higher concentrations of the hydrocarbon toluene, whereas TMR-derived cheese had significantly higher concentration of 2,3-butanediol. Ripening period resulted in significant alterations to cheese volatile profiles, with increases in acid-, alcohol-, aldehyde-, ester-, and terpene-based volatile compounds. This study has demonstrated the benefits of pasture-derived feeding systems for production of Cheddar cheeses with enhanced nutritional and rheological quality compared with a TMR feeding system.