An empirical study of the utility of a monte carlo model applicable to the determination of interference delays for multiple machine assignments on semiautomatic machines

One of the most difficult problems that confronts the work measurement engineer, in the establishment of time standards for multiple machine assignments, is the determination of machine interference. Several empirically developed deterministic models have found wide acceptance for use in determining interference solutions for synchronized multiple machine assignments on semiautomatic machines. A stochastic solution process (Monte Carlo Computer Simulation Model) is considered as a means for improving the portrayal of such a man and machine system

Public Perceptions of the Midwest\u27s Pavements - Iowa - Executive Summary

This report summarizes Iowa results of a five year, Pooled Fund study involving the Wisconsin, Iowa, and Minnesota DOTs designed to 1) assess the public\u27s perceptions of the departments’ pavement improvement strategies and 2) to develop customer-based thresholds of satisfaction with pavements on rural two lane highways in each state as related to the Departments’ physical indices, such as pavement ride and condition. The primary objective was to seek systematic customer input to improve the Departments’ pavement improvement policies by 1) determining how drivers perceive the departments’ pavements in terms of comfort and convenience but also in terms of other tradeoffs departments had not previously considered, 2) determining relationships between perceptions and measured pavement condition thresholds (including a general level of tolerance of winter ride conditions in two of the states), and 3) identifying important attributes and issues that may not have been considered in the past. Secondary objectives were 1) to provide a tool for systematic customer input in the future and 2) provide information which can help structure public information programs. A University of Wisconsin-Extension survey lab conducted the surveys under the direction of a multi-disciplinary team from Marquette University. Approximately 4500 drivers in the three states participated in the three phases of the project. Researchers conducted six focus groups in each state, approximately 400 statewide telephone interviews in each state and 700-800 targeted telephone interviews in each state. Approximately 400 winter ride interviews were conducted in Wisconsin and Minnesota. A summary of the method for each survey is included. In Phase I, focus groups were conducted with drivers to get an initial indication of what the driving public believes in regards to pavements and to frame issues for inclusion in the more representative state-wide surveys of drivers conducted in Phase II of the project. Phase II interviews gathered information about improvement policy trade-off issues and about preliminary thresholds of improvement in terms of physical pavement indices. In Phase III, a two step recruitment and post-drive interview procedure yielded thresholds of ride and condition index summarized for each state. Results show that, in general, the driving public wants longer lasting pavements and are willing to pay for them. They want to minimize construction delay, improve entire sections of highway at one time but they dislike detours, and prefer construction under traffic even if it stretches out construction time. Satisfaction with pavements does not correlate directly to a high degree with physical pavement indices, but was found instead to be a complex, multi-faceted phenomenon. A psychological model (after Fishbein/Ajzen) was applied to explain satisfaction to a respectable degree (R2 of .7) for the social sciences. Results also indicate a high degree of trust in the three DOTs which is enhanced when the public is asked for input on specific highway segments. Conclusions and recommendations include a three-step methodology for other state studies. Physical data thresholds based on both public satisfaction and the agreement to improve are presented for each state\u27s physical pavement indices (ride and condition). Recommendations for changes to the quality ranges of the physical indices where appropriate are also made

Shear Thickening and Scaling of the Elastic Modulus in a Fractal Colloidal System with Attractive Interactions

Dilute oil dispersions of fractal carbon black particles with attractive Van der Waals interactions display continuous shear thickening followed by shear thinning at high shear rates. The shear thickening transition occurs at $\dot\gamma_{c}\approx 10^{2}-10^{3}s^{-1}$ and is driven by hydrodynamic breakup of clusters. Pre-shearing dispersions at shear rates $\dot\gamma>\dot\gamma_{c}$ produces enhanced-modulus gels where $G' \sim \sigma_{pre-shear}^{1.5-2}$ and is directly proportional to the residual stress in the gel measured at a fixed sample age. The observed data can be accounted for using a simple scaling model for the breakup of fractal clusters under shear stress.Comment: 5 pages, 5 figures; v2: treating low shear rate date separately; edited title; reworked figure

Bootstrap approximation for the exchange-correlation kernel of time-dependent density functional theory

A new parameter-free approximation for the exchange-correlation kernel $f_{\rm xc}$ of time-dependent density functional theory is proposed. This kernel is expressed as an algorithm in which the exact Dyson equation for the response as well as a further approximate condition are solved together self-consistently leading to a simple parameter-free kernel. We apply this to the calculation of optical spectra for various small bandgap (Ge, Si, GaAs, AlN, TiO$_2$, SiC), large bandgap (C, LiF, Ar, Ne) and magnetic (NiO) insulators. The calculated spectra are in very good agreement with experiment for this diverse set of materials, highlighting the universal applicability of the new kernel.Comment: 4 figures 5 page

Tillage systems for summerfallow preparation in north-central Saskatchewan

Non-Peer ReviewedThis paper examines the agronomic and economic performance of seven summerfallow - spring wheat tillage systems studied over a 18 year period on a highly fertile silty clay loam soil at Melfort, Saskatchewan. During 1969-76, areas planted to wheat had the seedbed prepared with a cultivator and harrow; since 1977 one-half of each plot area received conventional seedbed preparation, the other half was sprayed with herbicide and zero till seeded. Overall, wheat yields averaged 3239 kg ha-1 for tillage alone, 3280 kg ha-1 for reduced tillage (combinations of tillage and herbicides), and 3347 kg ha-1 for herbicides only. On an annual basis, method of summerfallow preparation significantly influenced grain yields in only 6 of 18 years. In 3 of these years yields were lowest for tillage alone and highest for herbicides only; in 2 years yields were lowest for reduced tillage, and in 1 year yields were lowest for herbicides only. During 1977-86, preparation of the seedbed by tillage significantly increased yields (compared to zero till seeding) in 6 of 10 years, but it resulted in significantly lower yields in 4 of 10 years. Volume weight, protein content, and % P concentration in the grain were unaffected by the method used for fallow or seedbed preparation. Results of the economic analysis showed that total costs for the complete rotation systems were lowest for the all tillage treatment (average: $109 ha-1), intermediate for reduced tillage (average:$129 to $158 ha-1), and highest for herbicides only (average:$179 ha-1). Although the substitution of herbicides for mechanical tillage provided resource savings in the range of $2 to$10 ha-1, this was more than offset by the increased expenditures for herbicides. Net returns (income above all costs) were highest for tillage alone (average: $129 ha-1) and lowest for the herbicide only treatment in which paraquat or glyphosate was used in combination with dicamba (average:$54 ha-1) . The reduced tillage systems generally produced a net return that averaged $18 to$44 ha-1 lower than the traditional system. The maximum expenditure that could be made for herbicides to break even with the traditional system ranged from $22 to$29 ha-1 for the reduced tillage systems, and from $31 to$37 ha-1 for the herbicides only treatments. The study concluded that although the substitution of herbicides for some or all of the mechanical tillage is attractive to producers from an agronomic and soil conservation perspective, the present economic conditions and in particular, the high cost of herbicides, remains a major deterrent to widespread adoption

Application of current in situ hybridization techniques for grape phylloxera (Daktulosphaira vitifoliae, Fitch) and grapevine (Vitis spp. L.)

In situ hybridization and in situ PCR directly localize specific DNA and RNA sequences in tissues. To exactly focus on the processes occurring on cell- or tissue level, in situ techniques can be efficiently employed. Recent advances in viticultural research in the fields of genomics, proteomics and metabolomics are likely to employ these techniques to link DNA- or mRNA sequence information to physiological traits and processes occurring in the grapevine. In this paper, we present a range of possibilities for in situ techniques that can be applied in grapevine research. Two examples covering in situ PCR of grapevine roots and in situ hybridization of grape phylloxera will be given for illustration. Moreover, key steps of the techniques are discussed, which may be helpful to researchers aiming to employ in situ hybridization or in situ PCR.

Biosensing platform combining label-free and labelled analysis using Bloch surface waves

Bloch surface waves (BSW) propagating at the boundary of truncated photonic crystals (1D-PC) have emerged as an attractive approach for label-free sensing in plasmon-like sensor configurations. Due to the very low losses in such dielectric thin film stacks, BSW feature very low angular resonance widths compared to the surface plasmon resonance (SPR) case. Besides label-free operation, the large field enhancement and the absence of quenching allow utilizing BSW coupled fluorescence detection to additionally sense the presence of fluorescent labels. This approach can be adapted to the case of angularly resolved resonance detection, thus giving rise to a combined label-free / labelled biosensor platform. It features a parallel analysis of multiple spots arranged as a one-dimensional array inside a microfluidic channel of a disposable chip. Application of such a combined biosensing approach to the detection of the Angiopoietin-2 cancer biomarker in buffer solutions is reported

Ab initio many-body calculation of excitons in solid Ne and Ar

Absorption spectra, exciton energy levels and wave functions for solid Ne and Ar have been calculated from first principles using many-body techniques. Electronic band structures of Ne and Ar were calculated using the GW approximation. Exciton states were calculated by diagonalizing an exciton Hamiltonian derived from the particle-hole Green function, whose equation of motion is the Bethe-Salpeter equation. Singlet and triplet exciton series up to n=5 for Ne and n=3 for Ar were obtained. Binding energies and longitudinal-transverse splittings of n=1 excitons are in excellent agreement with experiment. Plots of correlated electron-hole wave functions show that the electron-hole complex is delocalised over roughly 7 a.u. in solid Ar.Comment: 6 page