Do International Commission of Agricultural and Biosystems Engineering (CIGR) dimension recommendations for loose housing of cows improve animal welfare?

Design of cubicles and self-locking barriers can affect cow skin alterations, lameness, and dirtiness. We investigated whether the International Commission of Agricultural and Biosystems Engineering (CIGR, Gainesville, FL)-recommended cattle housing design and dimensions actually improve cow welfare. We recorded individual cow body dimensions and assessed skin alterations, dirtiness, and lameness on 3,841 cows from 131 loose housing dairy farms (76 farms with cubicles and 55 straw-yard systems). We recorded the dimensions of cubicles (e.g., width, length, and so on) and of the self-locking barrier (e.g., top rail height and so on) for each farm. We then compared whether these dimensions would match with the individual cow body dimensions and whether compliance was associated with the occurrence of skin alterations, lameness, and dirtiness. Most cows (69.2%) had at least one skin alteration, on the tarsus (41.2%); neck, shoulder, or back (28.2%); hindquarters (22.0%); carpus (21.2%); and flank, side, or udder (11.6%). Lameness prevalence reached 17.9%. Most cows (83.1%) were scored dirty in at least one body region, mainly on the lower hind legs including hocks (81.4%), hindquarters (41.8%), and udder (21.0%). Cubicle recommendations were mostly met for cubicle resting length (75.9% of cubicles) and neck rail distance (NRD, 60.7%) but less so for overall cubicle length (CL, 38.8%), cubicle width (CW, 30.9%), neck rail height (NRH, 22.5%), head space (HS, 15.8%), partition zone for controlling lying position (ii zone, 15.7%), head and lunging space (HLS, 10.6%), partition head zone (i zone, 9.4%), and partition zone for pelvis freedom (iii zone, 6.0%). Compliance with design recommendations was associated with fewer skin alterations on neck (recommendation met for CW, CL, HS, and NRD and i zone), hindquarters (CW, CL, NRD), tarsus (CW, i and ii zones), and carpus (CW, HS, i and ii zones); less lameness (CW, NRH, i zone); and less dirtiness on the hindquarters (CW, HLS, NRD), lower hind legs (iii zone), and udder (CW, CL, HLS, NRD). Compliance with recommended i zone and ii zone design was associated with less injury and lameness but more dirtiness, whereas the opposite was true for the iii zone. Self-locking barrier recommendations were mostly met for bottom rail height (68.2%), separation wall width (SWW, 68.3%), and top rail height (TRH, 56.9%) and less often met for separation wall height (36.3%) and height difference between feeding floor and walking alley (26.5%). Risk for skin alterations on carpus and neck only decreased when SWW and TRH met recommendations. In conclusion, compliance with CIGR recommendations for some cubicle dimensions and neck rail position was associated with lower risk for cow welfare. However, the CIGR recommendations on cubicle partitions and self-locking barriers still leave welfare at risk and so need to be refined through further research with close observation of cow lying and feeding behavior.     

Sur l'existence de phases ternaires hydrogenees BeP2−xHy

The phosphidation of beryllium in the presence of traces of hydrogen leads to non stoichiometric ternary phases BeP_2?xH_y. The stoichiometric diphosphide BeP₂ cannot be obtained. The hydrogenated phases are black and non hygroscopic. The structural study with X rays diffraction, neutrons diffraction, electronic microdiffraction, as well as the crystallographic data from single crystal, provide evidence for a quadratic cell with $\text{a}\text{= 7,08}\text{A}\text{?}$ & $\text{c}\text{= 30,12}\text{A}\text{?}$. The stacking is diamond type when considering all the atoms : Be, P and H.     

Fatigue of V-notched members: Short crack behavior and endurance limit

A previous experimental investigation showed that the short crack behavior in severe V-notched geometries is essentially characterized by an initial transient variation of the crack opening level within the notch plastic zone. This result is exploited to derive a general formulation of the endurance limit of V-notched members. Analytical solutions for the stress intensity factor and the notch plastic zone extent are obtained to compute the effective crack driving force ΔK_eff as a function of notch geometry, crack length and nominal stress. Then, the endurance limit is determined as the nominal stress below which an initiated crack becomes non-propagating, i.e. by equating the minimum ΔK_eff value at the end of the plastic zone to a threshold value. By using Irwin's redistribution principle which allows us to make relations between the V-notch elastic and plastic fields, the following results are obtained. The endurance limit can be computed only from the V-notch “stress intensity factor” and the material threshold and cyclic yield stress. The endurance limit dependence on the threshold diminishes as the notch angle increases from zero and vanishes in the limit case of a smooth surface. When the notch contains a pre-existing crack, a Kitagawa-type endurance diagram is obtained. The uncracked notch endurance limit, the critical crack length and the slope of the decrease beyond this length, increase with increasing notch angle, and there is a total coincidence with the Kitagawa diagram in the limit case where the notch angle tends to 180°. This result shows that a global theory should govern at one and the same time the short crack behavior in smooth and severe geometries.     

FATIGUE LIFE PREDICTION OF WELDED JOINTS—A RE-ASSESSMENT

Abstract— Fatigue life prediction of welded joints needs an accurate and exhaustive theoretical Fracture Mechanics characterization of weld toe crack propagation. The method proposed by Albrecht et al. leads rapidly to accurate solutions of the LEFM δK-parameter. However, non-LEFM short crack behavior within the notch (weld toe) plastic zone must be taken into account. Available information on notch fatigue is surveyed, and practical cases where short crack growth is likely to occur are identified. Based on an elastoplastic finite element analysis, the LEFM validity limits and errors resulting from the misuse of LEFM in fatigue life prediction are quantified.     

Low-temperature plasmonics of metallic nanostructures

The requirements for spatial and temporal manipulation of electromagnetic fields on the nanoscale have recently resulted in an ever-increasing use of plasmonics for achieving various functionalities with superior performance to those available from conventional photonics. For these applications, ohmic losses resulting from free-electron scattering in the metal is one major limitation for the performance of plasmonic structures. In the low-frequency regime, ohmic losses can be reduced at low temperatures. In this work, we study the effect of temperature on the optical response of different plasmonic nanostructures and show that the extinction of a plasmonic nanorod metamaterial can be efficiently controlled with temperature with transmission changes by nearly a factor of 10 between room and liquid nitrogen temperatures, while temperature effects in plasmonic crystals are relatively weak (transmission changes only up to 20%). Because of the different nature of the plasmonic interactions in these types of plasmonic nanostructures, drastically differing responses (increased or decreased extinction) to temperature change were observed despite identical variations of the metal's permittivity.     

Skin optics

Quantitative dosimetry in the treatment of skin disorders with (laser) light requires information on propagation of light in the skin related to the optical properties of the individual skin layers. This involves the solution of the integro-differential equation of radiative transfer in a model representing skin geometry, as well as experimental methods to determine the optical properties of each skin layer. These activities are unified under the name skin optics. This paper first reviews the current status of tissue optics, distinguishing between the cases of: dominant absorption, dominant scattering, and scattering about equal to absorption. Then, previously published data as well as some current unpublished data on (human) stratum corneum, epidermis and dermis, have been collected and/or (re)analyzed in terms of absorption coefficient, scattering coefficient, and anisotropy factor of scattering. The results are that the individual skin layers show strongly forward scattering (anisotropy factors between 0.7 and 0.9). The absorption and scattering data show that for all wavelengths considered scattering is much more important than absorption. Under such circumstances, solutions to the transport equation for a multilayer skin model and finite beam laser irradiation are currently not yet available. Hence, any quantitative dosimetry for skin treated with (laser) light is currently lacking.     

单程波方程偏移算法的相位问题研究

利用稳相原理对叠后单程波方程偏移、二维和三维叠前偏移算法中的相位进行了分析和研究，从理论上论证了叠后偏移算法可以保持输入子波的相位特征，而叠前偏移算法会改变输入子波的相位特征，叠前单炮深度偏移结果相位与输入数据子波相位之间相差了一个因子。上述理论通过基本单位脉冲响应和一个水平反射界面模型的数值模拟得到了验证。从而从理论上解决了波动方程偏移与Kirchhoff积分偏移结果相位不一致问题，这对于正确标定反射层的振幅和深度具有实用意义。     

Effect of annealing on microstructure and hydrogenation properties of TiFe + X wt% Zr (X = 4, 8)

The effect of annealing on the hydrogenation characteristics of the TiFe alloy was investigated. Pellets of TiFe + X wt% Zr (X = 4, 8) were synthesized by arc melting, using industrial grade Fe (ASTM 10005) and Ti (ASTM B265 grade 1) and annealed at 1173 K for 24 h under argon atmosphere. Crystal structure and lattice parameters were determined by X-ray diffraction (XRD) pattern. Scanning electron microscopy (SEM) image of these alloys showed important differences in the microstructure before and after annealing. The main effect of annealing was to reduce the scale of the secondary phase. Change of composition for the TiFe phase and the secondary phases was relatively limited. Despite the relatively minor changes in crystal structures, the first hydrogenation kinetics was much slower and hydrogen capacity smaller for annealed samples compared to their as-cast counterparts. The mechanism responsible for the degradation of hydrogenation kinetics is still unclear but it may be due to modification in the chemical composition of the interface between the TiFe phase and the secondary phase.     

Effect of doping and particle size on hydrogen absorption properties of BCC solid solution 52Ti-12V-36Cr

The effect of chemical composition and particle size on the first hydrogenation of BCC alloy 52Ti-12V-36Cr were investigated. The alloy was studied in the undoped state and doped with 4%Zr. Three particle size ranges were selected: less than 0.5 mm, between 0.5 mm and 1 mm, and bigger than 1 mm. It was found that doping reduced the incubation time by more than two orders of magnitudes. Smaller particle size also reduces incubation time but only by a factor of three. The intrinsic hydrogenation kinetics were also significantly enhanced by doping. Moreover, there is some synergetic effect between doping and reduction of particle size. It was also found that incubation time depends on the average particle size and not on the distribution of particle sizes.