scholarly journals A performance evaluation of edging and trimming operations in U.S. hardwood sawmills

1994 ◽  
Vol 24 (7) ◽  
pp. 1450-1456
Author(s):  
Tony E. El-Radi ◽  
Steven H. Bullard ◽  
Phillip H. Steele
Keyword(s):  
Statistical Tests ◽  
Total Production ◽  
Usda Forest Service ◽  
Grade Difference ◽  
Length Width ◽  
Computer Controlled ◽  
Time Periods ◽  
Predicted Values ◽  
Short Time ◽  
Lumber Grade

Edger and trimmer operators must make constant decisions in short time periods on the amount of materials to remove from boards produced in the sawmill. Their decisions directly affect the total volume, grade, and value of the boards, and they therefore directly affect the total value of lumber produced. In recent years, many softwood sawmills have installed computer controlled edgers and trimmers with scanners and optimizers to achieve higher recovery rates. Before similar, relatively expensive, technologies can be seriously evaluated for the hardwood industry, however, the current performance of edging and trimming operations must be known. Using a sample of 3360 boards, compiled from 37 hardwood sawmills located in 16 states, lumber grade, length, width, and dollar values obtained in edging and trimming operations were compared with values predicted by USDA Forest Service scientists for the same lumber. Significant differences between edging and trimming performance and predicted values were determined via statistical tests. A linear regression model was formulated to study the influence of overedging, overtrimming, and grade difference on the percentage of predicted dollar value achieved. It was found that most sawmills edged a relatively low proportion of their total production. In 99% of the boards, edging and trimming operations achieved similar values for grade and length to those predicted by the USDA scientists. The value of the lumber increased significantly as the amount of overedging decreased.

scholarly journals Seasonal Estimates and Uncertainties of Snow Accumulation from CloudSat Precipitation Retrievals

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 363
Author(s):  
George Duffy ◽  
Fraser King ◽  
Ralf Bennartz ◽  
Christopher G. Fletcher
Keyword(s):  
Time Scales ◽  
Snow Water Equivalent ◽  
Spatial Scales ◽  
Snow Accumulation ◽  
High Latitudes ◽  
Percentage Points ◽  
Snow Water ◽  
Time Periods ◽  
Predicted Values ◽  
Good Agreement

CloudSat is often the only measurement of snowfall rate available at high latitudes, making it a valuable tool for understanding snow climatology. The capability of CloudSat to provide information on seasonal and subseasonal time scales, however, has yet to be explored. In this study, we use subsampled reanalysis estimates to predict the uncertainties of CloudSat snow water equivalent (SWE) accumulation measurements at various space and time resolutions. An idealized/simulated subsampling model predicts that CloudSat may provide seasonal SWE estimates with median percent errors below 50% at spatial scales as small as 2° × 2°. By converting these predictions to percent differences, we can evaluate CloudSat snowfall accumulations against a blend of gridded SWE measurements during frozen time periods. Our predictions are in good agreement with results. The 25th, 50th, and 75th percentiles of the percent differences between the two measurements all match predicted values within eight percentage points. We interpret these results to suggest that CloudSat snowfall estimates are in sufficient agreement with other, thoroughly vetted, gridded SWE products. This implies that CloudSat may provide useful estimates of snow accumulation over remote regions within seasonal time scales.

Recognition of Short Time Periods through Seriation

1977 ◽  
Vol 42 (4) ◽  
pp. 628-629 ◽  
Author(s):  
Clement W. Meighan
Keyword(s):  
Recent Article ◽  
Graphical Method ◽  
New Method ◽  
Time Discrimination ◽  
Time Periods ◽  
Short Time

One aspect of the recent article by Drennan (1976) merits some additional discussion. This has to do with the units of time that can be discriminated by seriation methods. One advance claimed for the new method proposed is that it allows for time placement within 25 years or so, stated as “ … finer than most traditional seriation.” In an article published 17 years ago, I showed this degree of time discrimination, with a much simpler graphical method of seriation.

scholarly journals How realistic are painted lightnings? Quantitative comparison of the morphology of painted and real lightnings: a psychophysical approach

2018 ◽  
Vol 474 (2214) ◽  
pp. 20170859 ◽  
Author(s):  
Mark Stromp ◽  
Alexandra Farkas ◽  
Balázs Kretzer ◽  
Dénes Száz ◽  
András Barta ◽  
...  
Keyword(s):  
Software Package ◽  
Relative Length ◽  
Quantitative Comparison ◽  
Angle Distribution ◽  
Morphological Parameters ◽  
Turning Angle ◽  
Local Maxima ◽  
Time Periods ◽  
Short Time ◽  
Number Of Branches

Inspired by the pioneer work of the nineteenth century photographer, William Nicholson Jennings, we studied quantitatively how realistic painted lightnings are. In order to answer this question, we examined 100 paintings and 400 photographs of lightnings. We used our software package to process and evaluate the morphology of lightnings. Three morphological parameters of the main lightning branch were analysed: (i) number of branches N b , (ii) relative length r , and (iii) number of local maxima (peaks) N p of the turning angle distribution. We concluded: (i) Painted lightnings differ from real ones in N b and N p . (ii) The r -values of painted and real lightnings vary in the same range. (iii) 67 and 22% of the studied painted and real lightnings were non-bifurcating ( N b  = 1, meaning only the main branch), the maximum of N b of painted and real lightnings is 11 and 51, respectively, and painted bifurcating lightnings possess mostly 2–4 branches, while real lightnings have mostly 2–10 branches. To understand these findings, we performed two psychophysical experiments with 10 test persons, whose task was to guess N b on photographs of real lightnings which were flashed for short time periods Δ t  = 0.5, 0.75 and 1 s (characteristic to lightnings) on a monitor. We obtained that (i) test persons can estimate the number of lightning branches quite correctly if N b  ≤ 11. (ii) If N b  > 11, its value is strongly underestimated with exponentially increasing difference between the real and estimated numbers. (iii) The estimation is independent of the flashing period Δ t of lightning photos/pictures. (iv) The estimation is more accurate, if skeletonized lightning pictures are flashed, rather than real lightning photos. These findings explain why artists usually illustrate lightnings with branches not larger than 11.

Scaling Issues in Landscape Ecology

2019 ◽  
pp. 14-41
Author(s):  
Kimberly A. With
Keyword(s):  
Landscape Ecology ◽  
Spatial Patterns ◽  
Spatial Scales ◽  
Ecological Data ◽  
Ecological Forecasting ◽  
Spatial And Temporal Scales ◽  
Time Periods ◽  
Patterns And Processes ◽  
Short Time ◽  
Over Time

Spatial patterns are ubiquitous in nature, and ecological systems exhibit patchiness (heterogeneity) across a range of spatial and temporal scales. Landscape ecology is explicitly concerned with understanding how scale affects the measurement of heterogeneity and the scale(s) at which spatial pattern is important for ecological phenomena. Patterns and processes measured at fine spatial scales and over short time periods are unlikely to behave similarly at broader scales and extended time periods. An understanding of pattern-process linkages, a major research focus in landscape ecology, thus requires an understanding of how patterns change with scale, spatially and temporally. The development of methods for extrapolating information across scales is necessary for predicting how landscapes will change over time as well as for ecological forecasting. This chapter explores how scaling issues affect ecological investigations, discusses problems in identifying the correct scale for research, and outlines when and how ecological data can be extrapolated.

scholarly journals The first in situ synthesis of 1,3-dioxan-5-one derivatives and their direct use in Claisen-Schmidt reactions

2019 ◽  
Vol 25 (1) ◽  
pp. 85-90 ◽  
Author(s):  
M. Javad Poursharifi ◽  
Mohammad M. Mojtahedi ◽  
M. Saeed Abaee ◽  
Mohammad M. Hashemi
Keyword(s):  
Acetic Acid ◽  
Aromatic Aldehydes ◽  
In Situ Synthesis ◽  
Stepwise Procedures ◽  
Time Periods ◽  
High Yields ◽  
Short Time ◽  
Direct Use ◽  
Derivatives Of

AbstractA method is developed for in situ generation of 1,3-dioxan-5-one derivatives 2. These compounds are simple precursors for accessing carbohydrate structures and previously had to be produced via stepwise procedures using excessive amounts of reagents. In the present work, three different derivatives of 2 were synthesized via the reaction of trialkoxyalkanes with dihydroxyacetone dimer 1 in the presence of acetic acid as the catalyst. In the same pot, derivatives of 2 were reacted with aromatic aldehydes and 30 mol% of pyrrolidine to obtain high yields of the respective bischalcones 3 within short time periods.

Ceramic Coatings for High Temperature Service

CORROSION ◽  
1960 ◽  
Vol 16 (7) ◽  
pp. 309t-311t ◽  
Author(s):  
S. W. BRADSTREET
Keyword(s):  
Ceramic Coating ◽  
Protective Coatings ◽  
Ceramic Coatings ◽  
Shear Stresses ◽  
Thermal Gradients ◽  
High Shear ◽  
Thermal Environments ◽  
Potential Value ◽  
Time Periods ◽  
Short Time

Abstract Several types of coatings may be used for service in extreme thermal environments. For moderate temperatures (to about 1700 C) for short time periods, these coatings may be rather simple refractory layers. Under the more severe conditions of ramjet and rocket operation, reinforced materials, graded substrate-coating interfaces, or multilayers are required. Where thermal gradients are severe and where high shear stresses and abrasion exist, composites must be used which utilize controlled ablation. The principles which appear to dominate the attachment of a ceramic coating to a variety of substrates are reviewed, and the deficiencies and advantages of different combinations are discussed. Principles for “tailoring” protective coatings for refractory metals is suggested, and a flame-sprayed ceramic coating of potential value as a combustion catalyst is used to illustrate these principles. 5.4.2

DEVELOPING PREDICTION EQUATIONS AND OPTIMIZING PRODUCTION OF THREE AM FUNGAL INOCULA UNDER ON-FARM CONDITIONS

2011 ◽  
Vol 47 (3) ◽  
pp. 529-537 ◽  
Author(s):  
MAHAVEER P. SHARMA ◽  
ALOK ADHOLEYA
Keyword(s):  
Mycorrhizal Fungi ◽  
Glomus Intraradices ◽  
Maximum Yield ◽  
Arbuscular Mycorrhizal ◽  
Total Production ◽  
Regression Equations ◽  
Farm Production ◽  
Predicted Values ◽  
Time Required ◽  
On Farm

SUMMARYThe production potential of three arbuscular mycorrhizal fungi (AMF), AM-1004 (Glomus intraradices), AM-1209 (mixed indigenous AMF) and AM-1207 (Mycorise, commercial inocula), were examined separately in three fractions/forms (root-based, soil-based and mixture of roots + soil) at 40, 60, 80 and 105 days in raised beds. The beds were amended with organic matter to develop regression equations for predicting optimal AM production vis-à-vis time required for particular inocula using infectious propagules (IP) as the independent variable. The IP production observed in the system was found to vary among the different inocula used. AM-1004 and AM-1207 produced significantly higher propagule counts in root or soil-based samples and a mixture of both at 105 days as compared to AM-1209. Based on two-way ANOVA, irrespective of time, AM-1004 (root/soil-based) produced a significantly larger number of propagules, whereas propagules in the crude inoculum (roots + soil) of all three inocula were not significantly different. On the other hand, irrespective of AMF, significantly more propagules (in all forms) were observed at 105 days. Similarly, irrespective of time, AM-1004 produced significantly higher root colonization (MCP, mycorrhizal colonization percentage) in all three forms (roots: 65.95%; soil: 24.32; soil + roots: 58.03%). The MCP in roots was increased significantly with time of multiplication. However, there was not much improvement in the MCP of soil or in soil + roots fractions beyond 80 days. Further, prediction of the number of IP for the three AM inocula was mathematically derived separately from the Mitscherlish-Bray equation (Y=a–b*exp (–cD). Based on the maximum yield of propagules of the three inocula observed and fitted into equations, root-based AM-1004 and AM-1209 inocula were found to be more efficient in producing propagules in 65 days as compared to AM-1207, which produced propagules in 76 days. While comparing the overall combinations, AM-1004 and AM-1209 inocula used either as roots, soil or a mixture of both and have greater potential in producing more propagules in the shortest span of time. While taking into account the predicted values of AM-1209 crude inoculum, about 12 IP g−1substrate can be achieved in 72 days. Therefore, if a farmer uses crude inocula (having zero time IP of about 0.8/g substrate) of AM 1209, a total production of about 12.12 million IP/m3can be achieved in 72 days. These can be used for on-farm production.

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