Yield Strength Analysis by Small Punch Test Using Inverse Finite Element Method

AbstractConsidering the change of material behavior in in-service component due to temperature, loading and irradiation, several micro-specimen techniques have been proposed to describe deformation and fracture behaviors of materials under different conditions. This paper investigates the mechanical characterization of materials by the experimental and numerical method of small punch test. A two-dimensional finite element model was established to simulate the deformation behavior of X80. The resulting Load-Displacement curve contains key information about the mechanical properties of the tested materials. Thus, an application of inverse finite element method was used in the investigation of mechanical properties of materials which have been tested by small punch test. The difference between experiment and simulation curves was defined as objective function based upon the calculation model established by ABAQUS and MATLAB procedure. Finally, the estimated results suggested confidence in the analysis of the inverse finite element method for material's yield strength

Balancing the availability of nutrients in manured soils

Non-Peer Reviewe

Effect of cultivation, tillage practice, and fertilization on total organic carbon, light fraction, and microbial biomass carbon in soils from the Loess Plateau of China and the Canadian prairies

Non-Peer ReviewedThree soils: Huangmian, Huihe, Heilu soil, from the Loess Plateau and one soil: Orthic Brown Chernozem, from the Canadian Prairies, were used to evaluate the effect of cultivation time, tillage system and fertilization, on total soil organic carbon (SOC), light fraction (LF), and microbial biomass carbon (MB-C). Upon cultivation, Huangmian soil lost 77% of total organic carbon within 5 years (0-20 cm), at a decrease rate of 2.15 tonnes C ha-1 yr-1. The Huihe soil lost 70% of total organic carbon at rate of 0.96-1.06 tonnes C ha-1 yr—1 over 42 years (0-20 cm). Comparably, the Orthic Brown Chernozem lost 11% and 44% of the total soil organic carbon mass (0-20 cm), after 40 and 80 years of cultivation respectively, at a corresponding rate of 0.17 tonnes C ha-1 yr-1 and 0.45 tonnes C ha-1 yr-1. Water erosion for the Huangmian and Huihe soil, and wind erosion for the Brown Chernozem during 1930’s, are the main reasons for organic carbon decline. The light fraction of organic carbon (LFOC) decreased more rapidly than total organic carbon: LFOC decreased by 73% and 90% for the Huangmian and Huihe soil for the corresponding period, and decreased by 70% and 74% for Brown Chernozem brought under cultivated 40 and 80 years ago respectively. The change of microbial biomass carbon (MB-C) showed same trend as total organic carbon and LFOC. On the Heilu soil, a 29% decrease of SOC, which was comparable to average 22% decline of SOC during about hundred years of cultivation on the Prairie, was observed after thousands of years of cultivation relative to native sod. Some management practices had a positive effect on restoring and maintaining soil organic carbon. On the Orthic Brown Chernozem, dry matter of light fraction in 0-5 cm was increased after no-tillage was practiced for 7 years. As well, LFOC in 0-5 cm was increased significantly after switching from cereal-fallow to continuous cropping for 10 years. Growing alfalfa for 10 years after 60 years cereal-fallow increased total organic carbon by 80% and 27% in 0-5 cm and 5-10 cm depths respectively, while dry matter of LF and LFOC were increased by 54% and 194%, and 245% and 286% in 0-5 cm and 5-10 cm respectively. Application of manure alone and manure plus chemical fertilizer was found to restore total organic carbon, LFOC, and MB-C in the Heilu soil

Early supplies of available nitrogen to the seed-row as affected by fertilizer placement

Non-Peer ReviewedA field experiment was conducted at Star City, (legal location SW6-45-16-W2); Saskatchewan, Canada from May to June 2000, to measure N and P supply rates from fertilizer band to canola seed row. Ion exchange resin membrane probes (PRS™-probes) were used to measure nutrient supply rates in four treatments (80 kg/ha of urea side-band, 80 kg/ha of urea mid-row band, check/no N (side-row)/P side-banded, check/no N (mid-row)/P seed placed. The treatments were arranged in a randomized complete block design with four replications. Two anion and cation exchange resin probes (PRS™-probes) were placed in each plot in the seed-row immediately after seeding and fertilizing. The probes were allowed to remain in the field for 2 days and replaced with another set of probes every 4 days for a total of 14 days until canola emerged. Ammonium-N, nitrate-N and P supply rates were calculated based on the ion accumulated on the probes. Grain and straw yield were measured in each plot. Urea side-row band treatments had significantly higher cumulative available N supply rates than mid-row banded placement. No significant differences were observed in P supply rates. The higher N rates (120 kg N/ha) showed lower grain yield in side banding than mid-row banding treatment possibly due to seedling damage, however the earlier fluxes of N into the seed-row observed with side-banding may be an advantage at lower N rates in N deficient soils

Optimizing an estuarine water quality monitoring program through an entropy-based hierarchical spatiotemporal Bayesian framework

The total maximum daily load program aims to monitor more than 40,000 standard violations in around 20,000 impaired water bodies across the United States. Given resource limitations, future monitoring efforts have to be hedged against the uncertainties in the monitored system, while taking into account existing knowledge. In that respect, we have developed a hierarchical spatiotemporal Bayesian model that can be used to optimize an existing monitoring network by retaining stations that provide the maximum amount of information, while identifying locations that would benefit from the addition of new stations. The model assumes the water quality parameters are adequately described by a joint matrix normal distribution. The adopted approach allows for a reduction in redundancies, while emphasizing information richness rather than data richness. The developed approach incorporates the concept of entropy to account for the associated uncertainties. Three different entropy-based criteria are adopted: total system entropy, chlorophyll-a standard violation entropy, and dissolved oxygen standard violation entropy. A multiple attribute decision making framework is adopted to integrate the competing design criteria and to generate a single optimal design. The approach is implemented on the water quality monitoring system of the Neuse River Estuary in North Carolina, USA. The model results indicate that the high priority monitoring areas identified by the total system entropy and the dissolved oxygen violation entropy criteria are largely coincident. The monitoring design based on the chlorophyll-a standard violation entropy proved to be less informative, given the low probabilities of violating the water quality standard in the estuary. Key Points Developed an entropy-based spatiotemporal framework for network redesign Multiple attribute decision making allows for multi-criteria optimization Showed differences between probability and entropy based redesign approache

On the Three-dimensional Central Moment Lattice Boltzmann Method

A three-dimensional (3D) lattice Boltzmann method based on central moments is derived. Two main elements are the local attractors in the collision term and the source terms representing the effect of external and/or self-consistent internal forces. For suitable choices of the orthogonal moment basis for the three-dimensional, twenty seven velocity (D3Q27), and, its subset, fifteen velocity (D3Q15) lattice models, attractors are expressed in terms of factorization of lower order moments as suggested in an earlier work; the corresponding source terms are specified to correctly influence lower order hydrodynamic fields, while avoiding aliasing effects for higher order moments. These are achieved by successively matching the corresponding continuous and discrete central moments at various orders, with the final expressions written in terms of raw moments via a transformation based on the binomial theorem. Furthermore, to alleviate the discrete effects with the source terms, they are treated to be temporally semi-implicit and second-order, with the implicitness subsequently removed by means of a transformation. As a result, the approach is frame-invariant by construction and its emergent dynamics describing fully 3D fluid motion in the presence of force fields is Galilean invariant. Numerical experiments for a set of benchmark problems demonstrate its accuracy.Comment: 55 pages, 8 figure

Direct Measurements of the Branching Fractions for D0→K−e+νeD^0 \to K^-e^+\nu_e and D0→π−e+νeD^0 \to \pi^-e^+\nu_e and Determinations of the Form Factors f+K(0)f_{+}^{K}(0) and f+π(0)f^{\pi}_{+}(0)

The absolute branching fractions for the decays $D^0 \to K^-e ^+\nu_e$ and $D^0 \to \pi^-e^+\nu_e$ are determined using $7584\pm 198 \pm 341$ singly tagged $\bar D^0$ sample from the data collected around 3.773 GeV with the BES-II detector at the BEPC. In the system recoiling against the singly tagged $\bar D^0$ meson, $104.0\pm 10.9$ events for $D^0 \to K^-e ^+\nu_e$ and $9.0 \pm 3.6$ events for $D^0 \to \pi^-e^+\nu_e$ decays are observed. Those yield the absolute branching fractions to be $BF(D^0 \to K^-e^+\nu_e)=(3.82 \pm 0.40\pm 0.27)$ and $BF(D^0 \to \pi^-e^+\nu_e)=(0.33 \pm 0.13\pm 0.03)$. The vector form factors are determined to be $|f^K_+(0)| = 0.78 \pm 0.04 \pm 0.03$ and $|f^{\pi}_+(0)| = 0.73 \pm 0.14 \pm 0.06$. The ratio of the two form factors is measured to be $|f^{\pi}_+(0)/f^K_+(0)|= 0.93 \pm 0.19 \pm 0.07$.Comment: 6 pages, 5 figure

Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta

Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector, the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and (7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure

BESII Detector Simulation

A Monte Carlo program based on Geant3 has been developed for BESII detector simulation. The organization of the program is outlined, and the digitization procedure for simulating the response of various sub-detectors is described. Comparisons with data show that the performance of the program is generally satisfactory.Comment: 17 pages, 14 figures, uses elsart.cls, to be submitted to NIM

Measurement of branching fractions for the inclusive Cabibbo-favored ~K*0(892) and Cabibbo-suppressed K*0(892) decays of neutral and charged D mesons

The branching fractions for the inclusive Cabibbo-favored ~K*0 and Cabibbo-suppressed K*0 decays of D mesons are measured based on a data sample of 33 pb-1 collected at and around the center-of-mass energy of 3.773 GeV with the BES-II detector at the BEPC collider. The branching fractions for the decays D+(0) -> ~K*0(892)X and D0 -> K*0(892)X are determined to be BF(D0 -> \~K*0X) = (8.7 +/- 4.0 +/- 1.2)%, BF(D+ -> ~K*0X) = (23.2 +/- 4.5 +/- 3.0)% and BF(D0 -> K*0X) = (2.8 +/- 1.2 +/- 0.4)%. An upper limit on the branching fraction at 90% C.L. for the decay D+ -> K*0(892)X is set to be BF(D+ -> K*0X) < 6.6%