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Oct 2021 DOI 10.14302/issn.2639-3166.jar-21-3875
Hassan Dahab MohamedCorresponding author
Department of Agric Eng. – College of Agriculture- University of Khartoum.
Repair and maintenance cost is considered as one of important items for machinery management and selection. The present study was carried out in Dongola area for tractor repair and maintenance costs estimation. The data was collected from records of Elshimalya Company for Agricultural Inputs. Forty four tractors rep resenting two sizes of tractors, 75hp and 150hp used in the area were selected for this study. Based on the data collected, regression correlation analysis was carried out and mathematical models were derived to predict the accumulated repair and maintenance (R and M) costs as percent of purchase price in relation to accumulated hours of use and age (years) for each tractor size, and also for the two sizes collectively. Five model forms (linear, logarithmic, polynomial, power and exponential) were derived and the power function was found the best fit to explain the relation. The accumulated Rand M costs as percent of purchase price (Y) was increased as the accumulated hours of use (x) and age (g) of the tractor in years were increased. A high correlation was found between the accumulated R and M cost and both accumulated hours of use and tractor age in years (Average R2 = 0.93). It was concluded that the power function was the best fit for repair and maintenance cost estimations and the following relations may be used as an average for estimation of the accumulated R and M costs as percent of purchase price (Y) with accumulated hours of use (x) and age (g) of the tractor: Y=0.028x0.662 (mean) Y=12.294g1.276 (mean).
Jul 2020 DOI 10.14302/issn.2642-3146.jec-20-3389
Tageldin Hago Ahmed SuhailCorresponding author
Faculty of Engineering, University of Khartoum, Sudan
Since the independence of South Sudan, Sudan lost 75% of its oil reserves, this led to major fuel shortages country wide, the fuel shortage raised the fuel prices and the overall transport prices. Scarcity led to black market trade of fuel specially in states away from the Capital City (Khartoum). Managing the available stock comes first before increasing the supply amount in order to solve the problem, one of the major fuel consumers to be managed is the transport sector specially the long haulage freight transport. Moving freight in Sudan is constrained by inadequate infrastructure and high costs. This paper covers specifically the long haulage freight transport between Khartoum State and Western side of the country (Darfur Region), Contributing to manage fuel consumption for trucks, taking into account trucks types used, roads, environmental impacts and mitigation measures applicable to save fuel . The results showed that the primary reason for the excessive fuel consumption is the usage of the rigid trucks (lorries) for transport specially the Hino700 series, this truck type, overload and absence of weight stations and control policies contributed significantly to deterioration of roads and transport efficiency decreasing. First step towards the solution would be in upgrading roads infrastructure assuring high quality along with enforced weight regulations and weight stations to protect roads from damages. High quality roads shall ease the usage of different truck types with different configurations. Then stablish a policy to force replacement of the low efficiency lorry truck types with high quality tractor semi-trailer combinations.
Oct 2019 DOI 10.14302/issn.2574-612X.ijpr-19-3045
Xu WeiCorresponding author
School of Psychology, Nanjing Normal University, Nanjing, China
Emotional conflict control refers to the ability to select task-relevant emotional information and ignore task-irrelevant emotional distractors. Previous fMRI studies provide some evidence about brain structure and function related to emotional conflict control. Yet, the underlying resting-state functional connectivity was largely unknown. Here, this is the first study to explore the resting-state functional connectivity related to emotional conflict. According to the literature which used the whole-brain analysis to investigate the key brain area associated with emotional conflict, we select the amygdala (AMY) as the seed region. We then investigated the association between emotional conflict and functional connectivity between amygdala (AMY) and another brain region in a large sample. We found the emotional conflict effect was positively correlated with functional connectivity strength between AMY (the seed ROI) and right supplementary motor area (SMA). This finding implied that the functional connectivity between AMY and SMA was linked to emotional conflict and that AMY was the key region which plays a crucial role in emotional conflict.
Apr 2018
PEREZ Jean-claudeCorresponding author
Maths and Computer Science, retired interdisciplinary researcher (IBM Emeritus),7 avenue de terre-rouge F33127 Martignas Bordeaux metropole France, phone 33 0781181112,
The global analysis of 3 human genomes of increasing levels of evolution (neanderthal / sapiens build34 of 2003 / sapiens hg38 of 2013) reveals 2 levels of numerical constraints controlling, structuring and optimizing the DNA sequences of these genomes. A global constraint - which we will call "HGO" for "Human Genome Optimum" - optimizes the genome at its global scale of 3.5 billion base pairs. This same operator when applied to each of the 24 individual chromosomes reveals a hierarchical structure of these 24 chromosomes according to a numerical spectrum of amplitude ½ Phi extending from chromosome 4 to chromosome 19. This first level of comparison reveals a very Great analogy between these 3 genomes. Then we introduce a global analysis method of roughness or fractal texture of the DNA sequences at the level of each chromosome. After having demonstrated that the chromosome4 seems to play a privileged role in the human genome, radically differentiating it from the 23 other chromosomes, we limit the study to the exhaustive analysis of different whole chromosomes4 relative to the 6 primates Homosapiens, Neanderthal, Chimpanzee, Orang-outan, Gorilla and Macaque. There are then remarkable resonances and periods - based on the sequences of Fibonacci and Lucas - totally differentiating the chromosomes 4 of these different primate species: 21 base pairs period for the chimpanzee and the urang-outan, 34 bases pairs period for Man, and 55 base pairs period for the gorilla. Finally, the major result is that the comparative analysis of the respective chromosomes4 of sapiens and neanderthal shows for the first time major differences in long-range fractal structures between the DNA sequences of these two genomes. Thus, while the chromosome4 of sapiens has an obvious resonance of 34 nucleotides, that of Neanderthal seems "torn" between two attractors of fractal textures, one on this same resonance 34, but with a roughness radically different from that of sapiens, While the other resonance is tuned to the number of Lucas 123. Finally, on a more theoretical level, this method reveals properties of "discrete digital standing waves" such as periods, resonances, phase shifts or phase positions. To conclude, we suggest that this chromosome4 could possibly play a role as a "referential" with respect to each of the 23 other chromosomes of the nuclear genome and possibly also with respect to the mitochondrial mtDNA genome.