A Total Product System Concept - a case study of the smart (tm) automobile

Increasing demand from consumers plus EU legislation has raised awareness within the automotive production sector of the urgent need to reduce the environmental impacts from the three main stages in vehicle life – car manufacture, car use and end-of life vehicle processing. The paper reviews how the originator and manufacturer of the smart automobile has worked directly with its main system partners to address environmental issues in these three stages while optimizing performance across the parameters of commercial viability. This required the creation of strategic relationships within the supply chain. Overall, this innovative approach is viewed in the context of a total product system. The smart car highlights the following critical areas: use of modularity in product design and production facility layout; emphasis on partner participation from product creation to after-sales; and the use of highly customised build-to-order product system to 'green' the entire supply chain. In particular, the case study compares the process characteristics empoyed at the smart car factory, called 'smartville', with more traditional approaches to vehicle manufacture. It exmaines these issues in a preliminary attempt to establish the actual or potential reduction of environmental impact in the three stages of vehicle life, including the role of main suppliers in this process

Zone production system for cotton: soil response

In a three-year study, the major advantage of a zone cotton production system with controlled traffic was determined to be reduction in tractor operations for field preparation and crop management without a reduction in yield. The study indicates that tillage is required under any surface where wheels are operated to return the soil to a low impedance for root exploration and to a conductive state for water infiltration. However, the soil managed with a zone system, with no traffic or tillage after initialization, was stable with lower soil impedance and higher water infiltration than soil in tilled and trafficked plots. Adoption of these findings will reduce unit production costs

Fine root development of alfalfa as affected by wheel traffic

Root development in alfalfa (Medicago satire L.) is dependent of many factors including the soil environment which is influenced by crop management procedures. Soil compaction, which is unavoidable under current management procedures, can have a detrimental effect on root development. The purpose of this field experiment was to compare the effects of controlled and conventional traffic management on alfalfa fine root growth in a Wasco sandy loam (coarse-loamy, mixed, nonacid thermic Typic Torriorthent). No wheel traffic and traffic only before planting were compared to two conventional systems that varied in the amount of traffic applied during crop production. Twenty months after planting, there was a significant decrease in fine root density (FRD) from single passes of traffic after each harvest down to a 0.45-m depth while several passes after each harvest significantly decreased FRD down to 1.8-m depth. Regardless of treatment, root density was greatest in the upper 0.1 m of soil decreasing to 1.8 m in the first summer. By the second summer FRD showed bimodal distribution with significantly fewer roots at 0.3 to 0.6 m compared to layers above and below this depth. Seasonally there was a significantly higher root density during the winter than the summer in the upper 0.3 m of soil. The results of this study shows that alfalfa fine roots more thoroughly exploit the soil volume in the absence of wheel traffic and that compaction from traffic diminished root growth to different depths depending on its intensity

Changes in infiltration under alfalfa as influenced by time and wheel traffic

Infiltration rates were measured for alfalfa, (Medicago saliva L., cv. WL514) subjected to treatments where wheel traffic was varied in terms of area covered and time of application on a Wasco sandy loam (coarse-loamy, mixed, nonacid thermic Xeric Torriorthent). Traffic treatments were (i) No-traffic, (ii) Preplant, (iii) Repeated, and (iv) traffic similar to what a grower would apply. Infiltration rates increased for all treatments, with increases being 240% for treatments without harvest traffic and 140% for treatments with harvest traffic Increases in infiltration were related to decreases in stand density. Slight packing (traffic) applied before the soil was flood-irrigated in 1983 increased infiltration rates 20% compared to flooding loosened soil (no traffic). Harvest traffic resulted in slower water movement in the soil

Alfalfa yield as affected by harvest traffic and soil compaction in a sandy loam soil

Harvesting alfalfa (Medicago saliva L.) results in plants being subjected to traffic at different times during the growth cycle with equipment having different wheel sizes and loads. The affect of this traffic could have important ramifications on yield. The objectives of this study were to determine the long-term effects of harvest traffic and soil compaction on alfalfa yield. In the first experiment, two conventional traffic systems were compared to alfalfa production with no traffic. A single traffic event, that covered 100% of the plot area 3 to 5 d after each swathing, compared to no traffic significantly decreased yield by 20% in the 1st yr, 16.5% in the 2nd yr, 14% in the 3rd yr, with no significant difference the 4th yr. There was no difference in total yield between nontrafficked and a typical grower's traffic pattern the 1st yr, but in the succeeding 3 yr there was a 5 to 17% reduction. The effects of soil compaction and harvest traffic on yield were separated in the second experiment. Alfalfa grown in moderately and heavily compacted soil had a 12 and 26% decrease respectively in seasonal total yield compared to the yield from plants grown in noncompacted soil the 1st yr. Annual yields were the same regardless of the degree of soil compaction in the 3rd yr. When harvest traffic was applied to alfalfa grown in extremely compacted soil there was an additional decrease in yield. It was not statistically significant the 1st yr, but in the following 2 yr, 1987 and 1988, yield was significantly reduced by 17.8 and 19.1%, respectively. Alfalfa yields were significantly reduced both by harvest traffic and compacted soil. To achieve optimum long-term alfalfa yields compacted soil must be tilled before planting and operations that reduce the area of the field subjected to traffic must be implemented

Alfalfa (Medicago sativa L.) water use efficiency as affected by harvest traffic and soil compaction in a sandy loam soil

Traffic during alfalfa harvest operations can cause soil compaction and damage to newly growing stems. Root exploration for soil water and nutrients, forage growth dynamics, and final yield can all be affected. The objectives of this study were to determine the long-term effects of harvest traffic and soil compaction on water-use efficiency (WUE) of alfalfa grown in a Wasco sandy loam (coarse-loamy, mixed, nonacid, thermic Typic Torriorthents). Alfalfa was planted into tilled soil and managed with or without harvest traffic. Plants subjected to traffic during harvest had a significantly lower WUE two out of the three years studied compared to plants that were never subject to traffic. The second experiment examined whether planting alfalfa into compacted soil and managed with or without harvest traffic altered WUE. Soil compaction had no affect on alfalfa WUE. It was significantly lower when grown in compacted soil and subjected to harvest traffic. It is suggested that the decrease in WUE caused by harvest traffic may be explained by plants allocating carbohydrates to damaged shoots and crowns instead of to above ground forage production. The area of the field affected by harvest traffic, which damages newly growing stems, should be minimized to increase crop water use efficiency

Stochastic Model for Surface Erosion Via Ion-Sputtering: Dynamical Evolution from Ripple Morphology to Rough Morphology

Surfaces eroded by ion-sputtering are sometimes observed to develop morphologies which are either ripple (periodic), or rough (non-periodic). We introduce a discrete stochastic model that allows us to interpret these experimental observations within a unified framework. We find that a periodic ripple morphology characterizes the initial stages of the evolution, whereas the surface displays self-affine scaling in the later time regime. Further, we argue that the stochastic continuum equation describing the surface height is a noisy version of the Kuramoto-Sivashinsky equation.Comment: 4 pages, 7 postscript figs., Revtex, to appear in Phys. Rev. Let

Instabilities in the two-dimensional cubic nonlinear Schrodinger equation

The two-dimensional cubic nonlinear Schrodinger equation (NLS) can be used as a model of phenomena in physical systems ranging from waves on deep water to pulses in optical fibers. In this paper, we establish that every one-dimensional traveling wave solution of NLS with trivial phase is unstable with respect to some infinitesimal perturbation with two-dimensional structure. If the coefficients of the linear dispersion terms have the same sign then the only unstable perturbations have transverse wavelength longer than a well-defined cut-off. If the coefficients of the linear dispersion terms have opposite signs, then there is no such cut-off and as the wavelength decreases, the maximum growth rate approaches a well-defined limit.Comment: 4 pages, 4 figure

The role of interparticle heterogeneities in the selenization pathway of Cu Zn Sn S nanoparticle thin films a real time study

Real time energy dispersive X ray diffraction EDXRD analysis has been utilized to observe the selenization of Cu Zn Sn S nanoparticle films coated from three nanoparticle populations Cu and Sn rich particles roughly 5 nm in size, Zn rich nanoparticles ranging from 10 to 20 nm in diameter, and a mixture of both types of nanoparticles roughly 1 1 by mass , which corresponds to a synthesis recipe yielding CZTSSe solar cells with reported total area efficiencies as high as 7.9 . The EDXRD studies presented herein show that the formation of copper selenide intermediates during the selenization of mixed particle films can be primarily attributed to the small, Cu and Sn rich particles. Moreover, the formation of these copper selenide phases represents the first stage of the CZTSSe grain growth mechanism. The large, Zn rich particles subsequently contribute their composition to form micrometer sized CZTSSe grains. These findings enable further development of a previously proposed selenization pathway to account for the roles of interparticle heterogeneities, which in turn provides a valuable guide for future optimization of processes to synthesize high quality CZTSSe absorber layer

Variational Approach to the Modulational Instability

We study the modulational stability of the nonlinear Schr\"odinger equation (NLS) using a time-dependent variational approach. Within this framework, we derive ordinary differential equations (ODEs) for the time evolution of the amplitude and phase of modulational perturbations. Analyzing the ensuing ODEs, we re-derive the classical modulational instability criterion. The case (relevant to applications in optics and Bose-Einstein condensation) where the coefficients of the equation are time-dependent, is also examined