727 research outputs found
Bayesian Inference For Exponential Distribution Based On Upper Record Range
This paper deals with Bayesian estimations of scale parameter of the
exponential distribution based on upper record range (Rn). This has been done
in two steps; point and interval. In the first step the quadratic, squared
error and absolute error, loss functions have been considered to obtain
Bayesian-point estimations. Also in the next step the shortest Bayes interval
(Hight Posterior Density interval) and Bayes interval with equal tails based on
upper record range have been found. Therefore, the Homotopy Perturbation
Method(HPM) has been applied to obtain the limits of Hight Posterior Density
intervals. Moreover, efforts have been made to meet the admissibility
conditions for linear estimators based on upper record range of the form mRn+d
by obtained Bayesian point estimations. So regarding the consideration of loss
functions, the prior distribution between the conjunction family has been
chosen to be able to produce the linear estimations from upper record range
statistics. Finally, some numerical examples and simulations have been
presented
The study of nano technology utilization in upgrading the quality of construction industry with fire-engineering approach
Today, the first requirement for increasing quality and strength in construction industry is utilization of appropriate and high quality materials so that usage of these materials, in addition to reducing maintenance costs and also upgrading the structure's longevity, in engineering respect through change on weight reduction and increasing strength in used materials, can cause general strength of the structure against earthquakes and probable runs due to natural disasters. This requirement is very significant in passive defense scope and this task will be considered in used material in main structure of a building and also in used materials in its frontage and in terminology elaborate work. Given that one of the effects of fire on the building part and parcel of passive defense, so, this look from the perspective of fire engineering is also of particular significance. Wide studies have been performed in this ground and various factories are trying to increase their produced materials quality in today competitive world with utilization of various technologies. One of technologies considered today is Nano technology which in fact by changing the molecular structure of a material causes creating special properties in it and utilization of these properties can answer needs of producers and users for increasing quality, longevity, strength and weight reduction. In this study, it is tried to introduce materials produced by Nano technology which have special properties like resistance against fire, settlement and weight reduction and increasing resistance in tolerance of strike and injected loads to the structure in defensive point of view in civil engineering scope. Keywords: Nano technology; passive defense; building material
An intelligent capacity management system for interface converter in AC-DC hybrid microgrids
An interface converter (IC) is used in an AC-DC hybrid microgrid (HMG) and its main tasks are frequency regulation in the AC side, adjusting the DC voltage, and controlling the power flow between AC/DC sides based on the droop control method. The IC should be capable of providing ancillary services such as reactive power supply and compensation of unbalanced and harmonic components in the AC side. However, the use of the IC to provide ancillary services occupies its capacity, which may interfere with the main tasks of the IC. In addition, it is shown in this paper that in unbalanced conditions, the effective power capacity of the IC is reduced by considering the current limit of the converter. In this case, the converter may not be able to perform the main task and provide all the necessary ancillary services at the same time, otherwise, it may be exposed to an overcurrent condition. Therefore, an efficient strategy is needed to manage the IC converter capacity to facilitate optimal use of the entire IC capacity even in unbalanced conditions. Given this challenge, this paper proposes an intelligent strategy for managing the IC capacity, which prioritizes the realization of the main task and the provision of ancillary services. The proposed strategy is evaluated, and its effectiveness is proven by simulation results in Matlab/Simulink
Biosuper as a phosphate fertilizer in a calcareous soil with low available phosphorus
Laboratory assays were conducted to produce phosphorus (P) biofertilizers from rock phosphate (RP), applying sulphur at different rates of 10, 15 and 20% and inoculated with Thiobacillus. A greenhouse experiment was carried out to evaluate the effect of the biofertilizers in a calcareous soil with low available P from the Qazvin plain of “Qazvin State”, grown with corn (Zea mays L.). The treatments were: rock phosphate (RP), biofertilizers produced in laboratory with sulphur and Thiobacillus (Biof1, Biof2 and Biof3), rock phosphate with sulphur (10, 15 and 20%) without Thiobacillus (Nbiof1, Nbiof2 and Nbiof3), Triple Super Phosphate (TSP) and a control without phosphorus. In this experiment, shoot dry matter, total P, Fe and Zn in shoots, and also soil available P, Fe and Zn were determined. Higher rates of measured parameters were obtained from biofertilizers with sulphur and Thiobacillus (Biof) and in Triple Super Phosphate (TSP). Biofertilizers with sulphur and Thiobacillus (Biof) and TSP increased plant parameters significantly compared with control or rock phosphate
Age and growth of the Mesopotamian barb, Capoeta damascina, in central Iran
Age and growth of Mesopotamian barb, Capoeta damascina, were studied in the Zayandehrud River, in central Iran, from March 2007 to April 2008. Among the 689 specimens studied, age groups in males ranged from 1+ to 9+ and that in females ranged from 1+ to 10+. The sex ratio (1 M: 1.6 F) was not significantly different from 1:1 ratio. Maximum fork length and weight was 39 cm and 1.115 g for males and 54.2 cm and 2.340 g for females. In all age classes, females were larger than males. The most frequent age groups were 3+ in males and 4+ in females. The highest value for condition factor was observed in June. The growth of C. damascina was described by von Bertalanffy growth curve as k=0.01, L_∞=56.2 cm, t_0=-0.63 for males and k = 0.05, L_∞=117.1 cm and t_0= -0.43 years for females. The length-weigh relationship was described as W=0.0169L^2.95 (r^2 =0.98) for males and as W=0.0155L2.99 (r^2 =0.99) for females, indicating an isometric growth pattern in both sexes. Growth performance index φ` was estimated as 5.73 for males and 6.53 for females, indicating a faster growth rate in females
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