scholarly journals Improving Log Trucking Efficiency by Using In-Woods Scales

2011 ◽  
Vol 35 (4) ◽  
pp. 178-183 ◽  
Author(s):  
Ryan P. Reddish ◽  
Shawn A. Baker ◽  
W. Dale Greene
Keyword(s):  
Coefficient Of Variation ◽  
Forest Products ◽  
Fuel Prices ◽  
Southern States ◽  
Vehicle Weight ◽  
Gross Vehicle Weight ◽  
The Mean ◽  
Weight Data

Abstract We evaluated weight data from 47,953 truckloads of wood delivered to forest products mills in nine southern states to determine the effect of in-woods scale use on reducing the variability of net and gross weights. Four mill-owning companies provided the data and indicated whether in-woods scales were used for each load. We used these data to compare the mean tare, net, and gross weights of truckloads using scales to those not using scales. Trucks using scales had average tare weights only 108 lb greater, but their net payload averaged 1,799 lb higher than trucks not using scales. The coefficient of variation for the net payload was 38% lower for loads with scales than those without (P < 0.001). Individual southern states have different regulations regarding maximum gross vehicle weight (GVW), so we calculated a GVW index to remove state bias and allow comparisons of loads across states. Loads using scales were within 2% of the legal maximum GVW 54% of the time compared with 30% for loads not weighed in-woods. We estimated haul costs for trucks using scales at $7.44 per ton, compared with $7.74 per ton for trucks not using scales (P < 0.001). We found that 11% of loads with in-woods scales had haul costs exceeding $8.00 per ton, compared with 32% of loads not using scales. Across all data, scales represent a 4% savings on per-ton haul costs with even greater savings available as fuel prices increase.

scholarly journals Improving Timber Trucking Performance by Reducing Variability of Log Truck Weights

2007 ◽  
Vol 31 (1) ◽  
pp. 12-16 ◽  
Author(s):  
Amanda K. Hamsley ◽  
W. Dale Greene ◽  
Jacek P. Siry ◽  
Brooks C. Mendell
Keyword(s):  
Confidence Level ◽  
Coefficient Of Variation ◽  
Forest Products ◽  
The Other ◽  
Us South ◽  
The Us ◽  
Variability Level ◽  
Gross Vehicle Weight ◽  
The Mean ◽  
Weight Data

Abstract We evaluated weight data from 79,760 truckloads delivered to 24 southern forest products mills to assess opportunities for improving trucking efficiency by reducing the variability of gross, tare, and net weights. We compared the mean gross vehicle weight (GVW) at each mill to the federal weight limit of 40 tons and to any mill overweight policy. A benchmark group of suppliers was identified at each mill as the five with the lowest coefficient of variation (CV) on their GVWs to compare with the other suppliers at each mill. All mills had mean GVWs significantly different from the federal limit at the 90% confidence level or stronger. A majority of loads delivered to each mill (77–100%) complied with mill GVW policies. At most mills, the benchmark group had higher mean GVWs and net weights, as well as lower GVW variability. Decreased GVW variability was associated with higher payloads. Mean tare weight and mean net weight exhibited an approximately 1:1 relationship at 15 mills. Benchmark groups at 14 mills had significantly larger payloads, and we project that they had 4–14% lower per-ton hauling costs than other suppliers at the mills. These results suggest that operating at the reduced variability level of the benchmark groups across the 221 million tons of roundwood annually consumed in the US South could result in a savings of $100 million annually.

Perceptions of Log Truck Weight Regulations Among Loggers and Forest Industry in Georgia, USA

2021 ◽  
Author(s):  
Joseph L Conrad
Keyword(s):  
The State ◽  
Transportation Costs ◽  
Forest Industry ◽  
Public Infrastructure ◽  
Truck Traffic ◽  
Telephone Surveys ◽  
Southern States ◽  
Vehicle Weight ◽  
Gross Vehicle Weight ◽  
Truck Weight

Abstract Georgia and other southern states have far lower gross vehicle weight (GVW) limits for log trucks than other US regions and other countries. Low GVW limits result in high hauling costs and truck traffic. In 2020, including tolerances, five-axle log tractor-trailers were allowed 38,102 kg (84,000 lb) GVW in Georgia. Telephone surveys of 30 loggers and 32 forest industry representatives from the state of Georgia were conducted to measure perceptions of weight regulations and assess support for alternative weights and configurations. The four alternatives included five axles, 39,916 kg (88,000 lb); six axles, 41,277 kg (91,000 lb); six axles, 45,359 kg (100,000 lb); and seven axles, 45,359 kg (100,000 lb) GVW. The majority of loggers and forest industry representatives stated that GVW limits for log trucks were too low. The average preferred GVW limits were 39,621 kg (87,350 lb) and 40,545 kg (89,387 lb) for loggers and forest industry, respectively. Loggers and forest industry supported the five-axle 39,916 kg (88,000 lb) configuration whereas many loggers opposed both 45,359 kg (100,000 lb) configurations. Loggers, forest industry, and policymakers should work to modernize weight laws to reduce hauling costs, maintain or improve safety, and protect public infrastructure. Study Implications Increasing gross vehicle weight (GVW) limits in combination with adding axles to tractor-trailers has been demonstrated to reduce both timber transportation costs and damage to public roads. This study found that loggers and forest industry supported additional GVW but were hesitant to support configurations that would necessitate upgrading log truck fleets. If Georgia is to make its weight limits competitive regionally and internationally, it will be necessary to clearly communicate the benefits of heavier trucks with more axles to skeptical loggers.

Design and development of manually operated gladiolus planter

2018 ◽  
Vol 5 (01) ◽  
Author(s):  
TAPAN K. KHURA ◽  
H. L. KUSHWAHA ◽  
SATISH D LANDE ◽  
PKSAHOO . ◽  
INDRA L . KUSHWAHA
Keyword(s):  
Coefficient Of Variation ◽  
Field Capacity ◽  
Power Source ◽  
Forward Speed ◽  
Cereal Crop ◽  
Maximum Coefficient ◽  
Coefficient Of Uniformity ◽  
The Mean ◽  
The Cost ◽  
Immense Potential

Floriculture is an age-old farming activity in India having immense potential for generating selfemployment and income to farmers. However, the cost of cultivation of flower is high as compared to cereal crop. Level of mechanization for different field operations is one but foremost reason for the higher cost of cultivation. As most of the Indian farmers are marginal and small, a need for manually operated gladiolus planter was felt. The geometric properties of gladiolus corm were determined for designing the seed metering system and seed hopper of the planter. The planter was evaluated in the field when pulled by two persons as a power source and guided by a person. The coefficient of variation and highest deviation from the mean spacing was observed as 12.93% and 2.65cm respectively. The maximum coefficient of uniformity of 90.59% was observed for a nominal corm spacing of 15cm at 0.56 kmh-1 forward speed. An average MISS percentage was observed as 2.65 and 2.25 for nominal corm spacing of 15 and 20 cm. The multiple index was zero for two levels corm spacing and forward speed of operation. The QFI was found in the range of 97.2 and 97.9 percent. The average field capacity of the planter was observed as 0.02 hah-1.The average draft requirement of the planter was found as 821 ± 50.3 N.

scholarly journals Technical note: Inherent benchmark or not? Comparing Nash–Sutcliffe and Kling–Gupta efficiency scores

2019 ◽  
Vol 23 (10) ◽  
pp. 4323-4331 ◽  
Author(s):  
Wouter J. M. Knoben ◽  
Jim E. Freer ◽  
Ross A. Woods
Keyword(s):  
Time Series ◽  
Coefficient Of Variation ◽  
Ad Hoc ◽  
Model Performance ◽  
Technical Note ◽  
Mean Flow ◽  
Model Adequacy ◽  
Robust Model ◽  
The Mean ◽  
Adequacy Assessment

Abstract. A traditional metric used in hydrology to summarize model performance is the Nash–Sutcliffe efficiency (NSE). Increasingly an alternative metric, the Kling–Gupta efficiency (KGE), is used instead. When NSE is used, NSE = 0 corresponds to using the mean flow as a benchmark predictor. The same reasoning is applied in various studies that use KGE as a metric: negative KGE values are viewed as bad model performance, and only positive values are seen as good model performance. Here we show that using the mean flow as a predictor does not result in KGE = 0, but instead KGE =1-√2≈-0.41. Thus, KGE values greater than −0.41 indicate that a model improves upon the mean flow benchmark – even if the model's KGE value is negative. NSE and KGE values cannot be directly compared, because their relationship is non-unique and depends in part on the coefficient of variation of the observed time series. Therefore, modellers who use the KGE metric should not let their understanding of NSE values guide them in interpreting KGE values and instead develop new understanding based on the constitutive parts of the KGE metric and the explicit use of benchmark values to compare KGE scores against. More generally, a strong case can be made for moving away from ad hoc use of aggregated efficiency metrics and towards a framework based on purpose-dependent evaluation metrics and benchmarks that allows for more robust model adequacy assessment.

Effects of the Fractional Laplacian Order on the Nonlocal Elastic Rod Response

2017 ◽  
Vol 3 (3) ◽  
Author(s):  
Giuseppina Autuori ◽  
Federico Cluni ◽  
Vittorio Gusella ◽  
Patrizia Pucci
Keyword(s):  
Probability Density Function ◽  
Probability Density ◽  
Density Function ◽  
Coefficient Of Variation ◽  
Fractional Laplacian ◽  
Numerical Procedure ◽  
Elastic Rod ◽  
The Mean ◽  
Distributed Forces ◽  
Nonlinear Fashion

In this paper, we yield with a nonlocal elastic rod problem, widely studied in the last decades. The main purpose of the paper is to investigate the effects of the statistic variability of the fractional operator order s on the displacements u of the rod. The rod is supposed to be subjected to external distributed forces, and the displacement field u is obtained by means of numerical procedure. The attention is particularly focused on the parameter s, which influences the response in a nonlinear fashion. The effects of the uncertainty of s on the response at different locations of the rod are investigated by the Monte Carlo simulations. The results obtained highlight the importance of s in the probabilistic feature of the response. In particular, it is found that for a small coefficient of variation of s, the probability density function of the response has a unique well-identifiable mode. On the other hand, for a high coefficient of variation of s, the probability density function of the response decreases monotonically. Finally, the coefficient of variation and, to a small extent, the mean of the response tend to increase as the coefficient of variation of s increases.

Calibration of Experiments on Perennial Crops using Covariance Analysis: the Case of Coconut

1986 ◽  
Vol 22 (4) ◽  
pp. 353-361
Author(s):  
Tilak Abeysinghe
Keyword(s):  
Coefficient Of Variation ◽  
Experimental Error ◽  
Covariance Analysis ◽  
Mean Square ◽  
Perennial Crops ◽  
Randomized Design ◽  
Calibration Experiment ◽  
Experimental Yield ◽  
The Mean

SUMMARYThe calibrating efficiency of the pre-experimental yield of coconuts was examined using ten years data from a calibration experiment. On the basis of a fully randomized design it was found that the two-year pooled pre-experimental yield on four-tree plots produces consistent calibration and reduces the experimental error mean square by about 73%. This brings down the mean coefficient of variation to 9.7% from its pre-calibration levels of 36 on one-tree plots and 18 on four-tree plots.

Estimating the intra- and inter-individual imprecision of manual pipetting

2017 ◽  
Vol 55 (7) ◽  
Author(s):  
Giuseppe Lippi ◽  
Gabriel Lima-Oliveira ◽  
Giorgio Brocco ◽  
Antonella Bassi ◽  
Gian Luca Salvagno
Keyword(s):  
Coefficient Of Variation ◽  
Biological Samples ◽  
Inverse Correlation ◽  
Distilled Water ◽  
Years Of Experience ◽  
Laboratory Practice ◽  
Scientific Publications ◽  
Plastic Container ◽  
Water Solutions ◽  
The Mean

AbstractBackground:Despite the importance of manual pipetting of fluids such as water, solutions, buffers, reagents, or biological samples in daily laboratory practice, the intra- and inter-individual imprecision of this activity has not been recently described in scientific publications.Methods:Twenty laboratory operators were randomly enrolled for this study. Imprecision of manual pipetting was estimated by asking each laboratory professional to dispense 1 mL, 100 μL or 10 μL of distilled water for 10 consecutive times with three certified pipettes into a 50-mL plastic container placed into a gravimetric balance. The weight of the water dispensed was systematically recorded for each of the 10 repeated attempts, and the inter- and intra-operator imprecision was finally calculated and expressed as coefficient of variation (CV%).Results:The mean intra-individual imprecision was 5.7% (range, 0%–11.8%) for pipetting 10 μL, 0.8% (range, 0.4%–1.9%) for pipetting 100 μL, and 0.2% (range, 0.1%–0.5%) for pipetting 1 mL. Overall, the mean inter-individual imprecision was 8.1% for pipetting 10 μL, 1.1% for pipetting 100 μL and 0.4% for pipetting 1 mL. A significantly inverse correlation was found between intra-individual pipetting imprecision and the amount of water dispensed (r = –0.80; p<0.001). No significant correlation was observed between individual pipetting performance and sex, age, qualification, and years of experience in the laboratory.Conclusions:The results of this study show that manual pipetting is plagued by a considerable intra- and inter-individual imprecision, which is inversely correlated with the amount of fluid dispensed.

scholarly journals Probabilistic Bearing Capacity of a Pavement Resting on Fibre Reinforced Embankment Considering Soil Spatial Variability

2021 ◽  
Vol 7 ◽  
Author(s):  
Kouseya Choudhuri ◽  
Debarghya Chakraborty
Keyword(s):  
Spatial Variability ◽  
Soil Properties ◽  
Bearing Capacity ◽  
Coefficient Of Variation ◽  
Friction Angle ◽  
Horizontal Scale ◽  
Vertical Scale ◽  
Scale Of Fluctuation ◽  
The Mean ◽  
The Finite Difference Method

This paper intends to examine the influence of spatial variability of soil properties on the probabilistic bearing capacity of a pavement located on the crest of a fibre reinforced embankment. An anisotropic random field, in combination with the finite difference method, is used to carry out the probabilistic analyses. The cohesion and internal friction angle of the soil are assumed to be lognormally distributed. The Monte Carlo simulations are carried out to obtain the mean and coefficient of variation of the pavement bearing capacity. The mean bearing capacity of the pavement is found to decrease with the increase in horizontal scale of fluctuation for a constant vertical scale of fluctuation; whereas, the coefficient of variation of the bearing capacity increases with the increase in horizontal scale of fluctuation. However, both the mean and coefficient of variation of bearing capacity of the pavement are observed to be increasing with the increase in vertical scale of fluctuation for a constant horizontal scale of fluctuation. Apart from the different scales of fluctuation, the effects of out of the plane length of the embankment and randomness in soil properties on the probabilistic bearing capacity are also investigated in the present study.

scholarly journals Use of Frenum in Determining the Original Vertical Position of Teeth

2013 ◽  
Vol 7 (1) ◽  
pp. 44-46 ◽  
Author(s):  
KD Prasad ◽  
H Alva
Keyword(s):  
Coefficient Of Variation ◽  
Vertical Position ◽  
Central Incisor ◽  
Incisal Edge ◽  
The Mean ◽  
Natural Dentition ◽  
Lingual Frenum ◽  
Functional Position

ABSTRACT Purpose To determine the functional position of labial, lingual and buccal frenii with the corresponding central incisor, premolar or molars in natural dentition. Materials and method 20 dentate subjects between 20-40years of age were selected for the study. Maxillary and mandibular impressions were made and the distance from anterior attachment of frenum to the cusp tip of the corresponding tooth was measured. Result The mean distance between the anterior attachment of labial frenum to the incisal edge of incisor was 12.25mm, the mean distance between the anterior attachment of buccal frenum of right side to cusp tip of corresponding teeth was 12.75mm and left side was 12.8mm and the mean distance between the anterior attachment of lingual frenum to incisal edge of incisor was 15.4mm. The coefficient of variation were 14.7%, 16.65%, 15.75% and 6.4% respectively. Conclusion The distance between the anterior attachment of the frenum to the cusp tips/incisal edges can be used as a pre-extraction record for determining the original vertical position of teeth.

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