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The Effects of Slab Size on Pavement Life Cycle Cost
Parsons, Timothy A.,Hall, Jim W.Jr Korean Society of Road Engineers 2006 한국도로학회논문집 Vol.8 No.2
The purpose of this study was to determine the effect of expansion joint spacing (slab size) on the life cycle costs of owning Portland Cement Concrete (PCC) airfield pavements. Previous research has shown that slab size has a statistically significant impact on pavement performance. A probabilistic life cycle cost analysis was performed to determine if the effect of slab size on pavement performance would affect the total cost of ownership of PCC pavements. Data from 48 Pavement Condition Index (PCI) inspections of military and civilian airfields were used to develop probability-of-distress-by-condition curves, which were then used to develop probabilistic cost-of-repair-by-condition curves. A present worth life cycle cost analysis was then performed for various slab sizes, using construction costs, rehabilitation costs, and maintenance costs. Maintenance costs were determined by assuming a condition deterioration rate appropriate for each slab size and applying the cost-by-condition curves. The probabilistic cost-of-repair-by-condition curves indicated that smaller slabs are more expensive to repair on a unit cost basis. Life cycle cost analysis showed that larger slabs have a higher total cost of ownership than smaller slabs due to a faster rate of deterioration.
Evaluation of a Nutrition Model in Predicting Performance of Vietnamese Cattle
Parsons, David,Van, Nguyen Huu,Malau-Aduli, Aduli E.O.,Ba, Nguyen Xuan,Phung, Le Dinh,Lane, Peter A.,Ngoan, Le Duc,Tedeschi, Luis O. Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.9
The objective of this study was to evaluate the predictions of dry matter intake (DMI) and average daily gain (ADG) of Vietnamese Yellow (Vang) purebred and crossbred (Vang with Red Sindhi or Brahman) bulls fed under Vietnamese conditions using two levels of solution (1 and 2) of the large ruminant nutrition system (LRNS) model. Animal information and feed chemical characterization were obtained from five studies. The initial mean body weight (BW) of the animals was 186, with standard deviation ${\pm}33.2$ kg. Animals were fed ad libitum commonly available feedstuffs, including cassava powder, corn grain, Napier grass, rice straw and bran, and minerals and vitamins, for 50 to 80 d. Adequacy of the predictions was assessed with the Model Evaluation System using the root of mean square error of prediction (RMSEP), accuracy (Cb), coefficient of determination ($r^2$), and mean bias (MB). When all treatment means were used, both levels of solution predicted DMI similarly with low precision ($r^2$ of 0.389 and 0.45 for level 1 and 2, respectively) and medium accuracy (Cb of 0.827 and 0.859, respectively). The LRNS clearly over-predicted the intake of one study. When this study was removed from the comparison, the precision and accuracy considerably increased for the level 1 solution. Metabolisable protein was limiting ADG for more than 68% of the treatment averages. Both levels differed regarding precision and accuracy. While level 1 solution had the least MB compared with level 2 (0.058 and 0.159 kg/d, respectively), the precision was greater for level 2 than level 1 (0.89 and 0.70, respectively). The accuracy (Cb) was similar between level 1 and level 2 (p = 0.8997; 0.977 and 0.871, respectively). The RMSEP indicated that both levels were on average under-or over-predicted by about 190 g/d, suggesting that even though the accuracy (Cb) was greater for level 1 compared to level 2, both levels are likely to wrongly predict ADG by the same amount. Our analyses indicated that the level 1 solution can predict DMI reasonably well for this type of animal, but it was not entirely clear if animals consumed at their voluntary intake and/or if the roughness of the diet decreased DMI. A deficit of ruminally-undegradable protein and/or a lack of microbial protein may have limited the performance of these animals. Based on these evaluations, the LRNS level 1 solution may be an alternative to predict animal performance when, under specific circumstances, the fractional degradation rates of the carbohydrate and protein fractions are not known.
Brandon Parsons,Shahdad Naghshpour 중앙대학교 경제연구소 2023 Journal of Economic Development Vol.48 No.4
The study uses an unbalanced panel of 103 countries, with data from 1988 to 2018, to examine the relationship between ethnic fractionalization, ethnic tension, religious tension, and the Gini coefficient. The econometric model uses Driscoll and Kraay standard errors to account for heteroscedasticity, autocorrelation, and cross-sectional dependence. The data is categorized based on income levels and regional distinctions to identify and understand the varying patterns and trends across different groups. Religious tension is statistically significant in more cases than ethnic fractionalization or ethnic tension. Increases in religious tension worsen income distribution. Ethnic tension is significant only in the lowest tension categories in the full and non-OECD panels. Increases in ethnic fractionalization can either worsen or improve income distribution, depending on the panel. Findings indicate that cultural tension can exacerbate economic conditions, potentially driving the observed deterioration in income distribution.