REASSESSMENT OF UNCERTAINTY EXPANSION BY LINEAR ADDITION OF LONG-TERM COMPONENTS FROM TOP-DOWN INFORMATION

ABSTRACT Since radiocarbon accelerator mass spectrometry (14C AMS) is considered a high-precision technique, reassessment of the measurement uncertainty has been a topic of interest. Scientists from analytical and metrological fields have developed the top-down and bottom-up measurement of uncertainty approaches. The 14C quoted error should approximate the uncertainty of long-term repetitions of the top-down approach in order to be realistic. The novelty of this paper is that the uncertainty of both approaches were approximated to each other. Furthermore, we apportioned the graphitization, instrumentation, and bias components in order to additively expand the quoted error. Our results are comparable to error multipliers and to long-term repeatability studies reported by other laboratories. Our laboratory was established in late 2012 with N2 as stripper gas and 7 years later, we changed to helium stripper. Thus, we were able to compare both gases, and demonstrate that helium is a better stripper gas. In absolute F14C units, the ranges of graphitization+bias combined uncertainties were (0.7 to 4.1) × 10–3 for N2 and (0.7–3.0) × 10–3 for He depending on the standard 14C content. The error multiplier for He defined as the expanded uncertainty over quoted error, in average, was 1.7; while without the bias, the multiplier was 1.3.

Nitrogen fertilization of self-seeding Italian ryegrass: effects on plant structure, forage and seed yield

ABSTRACT: This study aimed to evaluate the effect of different levels of self-seeding Italian ryegrass (Lolium multiflorum Lam.) and nitrogen rates - applied additionally after two defoliations - on plant structure, in forage and seed yield. Levels of self-seeding were classified as very high (777 kg ha-1), high (736 kg ha-1), intermediate (624 kg ha-1), and low (234 kg ha-1). Populations were fertilized with zero, 20.25, 40.50, and 60.75 kg ha-1 of supplemental nitrogen applied after two defoliations; respectively, in very high, high, intermediate, and low levels. Higher levels of self-seeding promoted greater forage yield and uniformity of vegetation structure. Number of fertile tillers and number of seeds per plant have benefited by the combination of high self-seeding and supplemental nitrogen fertilization. Despite influencing the uniformity and amount of forage obtained in two defoliations, the very high and low self-seeding levels did not differ in Italian ryegrass seed production. However, linear addition for this same variable was obtained with the inclusion of supplemental nitrogen fertilization. In pastures from low and intermediate self-seeding levels, total dry mass increases linearly with the levels of nitrogen fertilization assessed in this research.

Modifying Additives Effect on Use Properties of Asphalt Concrete

The article dwells on the results of the survey of the asphalt concrete modified with various additives. It contains the results of the impact made by the modifying additives on the physical mechanic and performance properties (rutting resistance, fatigue life and permanent deformation accumulation resistance) of the Type A Grade I asphalt concretes. In the article the regularities of the influence exerted by the formula-related and technological factors on the asphalt concrete properties were established. Consistent with the obtained results forecasting of rutting in accordance with AVTODOR STO 2.28-2016 and forecasting of fatigue damage accumulation on the basis of the Miner’s cumulative model of damage linear addition were executed. On the basis of the forecast results the interrepair life of the road structures with the pavement courses of asphalt concretes containing the surveyed modifiers was evaluated.

On the invariance of the relative rest in doubly special relativity

In the framework of the most-studied doubly special relativity models the use of the naive formula v = dE/dp has been argued to lead to inconsistencies connected to different rules of transformation, under boosts, of particles with the same energy but with different masses. In this paper, we show that, at least in 1 + 1 dimensions, doubly special relativity can be formulated in such a way that the formula v = dE/dp is fully consistent with the invariance of the relative rest, easily fitting to the relativity principle. It is also argued that, always in 1 + 1 dimensions, is not necessary to renounce to the usual (commutative) Minkowski spacetime endowed with energy-independent boost transformations. The compatibility of the approach with superluminal propagation, with linear addition rule for energy, and possible extensions to 3 + 1 dimensions are also discussed.

Mooring Analysis of a Weathervaning FPSO in Bi-Directional Sea-States

Experimental studies were carried out at the Institute for Ocean Technology, Canada, in collaboration with the University of Western Australia (UWA) to assess the response of a moored 1:60 scaled Floating Production Storage and Offloading (FPSO) model in bi-directional seastates. The seastates comprise of a regular swell approaching in the head sea condition, and a JONSWAP wind sea approaching at various angles. The FPSO was moored in position by four spring-loaded mooring lines attached to an internal turret about which the model could weathervane. Previous papers by the authors have described the unpredictable yaw instability of the FPSO driven by long period swells, which was evidenced in the experiments. This creates difficulties in comparing motions from unidirectional and bi-directional seas, because the headings alter the response. However, the mooring tensions are relatively immune to yaw instabilities and this paper discusses effects of bi-directional seas on the mooring tensions. Numerical simulations are conducted using a time domain analysis software which simulates the motions of floating and moored structures in response to irregular seas. Simulations based on the software when compared with model tests at 45, 60 and 90 deg separation between the sea and swell shows reasonable agreement in terms of mooring tensions. Simulations are then conducted for a range of separation angles, and the effects of bi-directionality are further evaluated. It is found that a linear addition of the individual seastates can produce non-conservative results, which reinforces the fact that bi-directional seastates are important considerations for offshore operations of an FPSO.