328 research outputs found
Distributed multilevel optimization for complex structures
Optimization problems concerning complex structures with many design variables may entail an unacceptable computational cost. This problem can be reduced considerably with a multilevel approach: A structure consisting of several components is optimized as a whole (global) as well as on the component level. In this paper, an optimization method is discussed with applications in the assessment of the impact of new design considerations in the development of a structure. A strategy based on fully stressed design is applied for optimization problems in linear statics. A global model is used to calculate the interactions (e.g., loads) for each of the components. These components are then optimized using the prescribed interactions, followed by a new global calculation to update the interactions. Mixed discrete and continuous design variables as well as different design configurations are possible. An application of this strategy is presented in the form of the full optimization of a vertical tail plane center box of a generic large passenger aircraft. In linear dynamics, the parametrization of the component interactions is problematic due to the frequency dependence. Hence, a modified method is presented in which the speed of component mode synthesis is used to avoid this parametrization. This method is applied to a simple test case that originates from noise control. \u
Qualitative and Quantitative Evaluation Techniques of New Infill Designs in Historic Context
With the continuing advancement in material technology and construction techniques, architects face a greater set of options and challenges when it comes to designing in historic settings. In the meantime after the ICOMOS agreement, every country adapted the policy according to their own culture and settings, therefore every architect in their respective country started interpreting the charters, and the design review processes in their own way. Working on the new addition to historic context gave rise to familiar characteristics in design, especially in the infill designs, which is “Replication and Contrast”, which in turn sparked the question, how to evaluate whether a building is properly fitting in its context with whatever approach employed. This paper aims to answer this question by conducting a literature review covering First, the qualitative evaluation approach which compromises of surveys and pre-visualization in order to identify the main visual properties that improve the contextual compatibility of the new designs in the historical context, and quantitative techniques focused more on the mathematical scientific cognitive results of all aspects of the architectural elements within historic settings. A comparison has been made on each result achieved and an assessment of their reliance or authenticity has been tested in order to find and bridge the gap between tangible and intangible values when judging “fit” in a historic setting. The results showed that the qualitative evaluation if followed properly it could be very promising, but it always leaves room for skepticism as the result is expected to change based on the size and the characteristics of the participants. The quantitative evaluation provided a more tangible evidence of the contextual fit in terms of architectural elements like size, proportion, and scale. Finally, a suggestion was made in order to provide a better, and a more comprehensive technique merging both methods together and trying to incorporate more of three-dimensional aspects of the building instead of the two dimensionality of the current assessment techniques
Adjustment of costly extra-group paternity according to inbreeding risk in a cooperative mammal
Females of many animal species seek mating opportunities with multiple males, despite being able to obtain sufficient sperm to father their offspring from a single male. In animals that live in stable social groups, females often choose to mate outside their group resulting in extra-group paternity. One reason proposed to explain female choice for extra-group males is to obtain compatible genes, for example in order to avoid inbreeding depression in offspring. The benefits of such extra-group paternities could be substantial if they result in fitter, outbred offspring. However, avoiding inbreeding in this way could be costly for females, for example through retaliation by cuckolded males or through receiving aggression whilst prospecting for extra-group mating opportunities. We investigate the costs and benefits of extra-group paternity in the banded mongoose Mungos mungo, a cooperatively breeding mammal in which within-group mates are sometimes close relatives. We find that pups born to females that mate with extra-group males are more genetically heterozygous, are heavier and are more likely to survive to independence than pups born to females that mate within their group. However, extra-group matings also involve substantial costs as they occur during violent encounters that sometimes result in injury and death. This appears to lead female banded mongooses to adaptively adjust extra-group paternity levels according to the current risk of inbreeding associated with mating within the group. For group-living animals, the costs of inter-group interactions may help to explain variation in both inbreeding rates and extra-group paternity within and between species
Effective Mass Dirac-Morse Problem with any kappa-value
The Dirac-Morse problem are investigated within the framework of an
approximation to the term proportional to in the view of the
position-dependent mass formalism. The energy eigenvalues and corresponding
wave functions are obtained by using the parametric generalization of the
Nikiforov-Uvarov method for any -value. It is also studied the
approximate energy eigenvalues, and corresponding wave functions in the case of
the constant-mass for pseudospin, and spin cases, respectively.Comment: 12 page
Dalaman tarım işletmesinde yetiştirilen siyah-alacalarda buzağılama mevsiminin süt verimine etkisi
Data of 866 lactations collected from 251 cows raised at Dalaman State Farm in Mugla province between 1989
and 1996 were analyzed. Two calving seasons were determined on data set based on average monthly air
temperature. These are the first calving season (November 1 - April 30 ) which is within the comfort zone for
cows, and the second calving season (May 1 - October 31 ). Milk yield, calving year, lactation number and
calving season were evaluated. The effect of lactation number (p<0.01), calving year (p<0.01) and, calving
season (p<0.01) on 305-d milk yield were found statistically significant. The least-square means and standard
errors of milk yield for the first and the second calving season were 7493.54±70.29 kg and 7180.63±81.08 kg,
respectively.Mugla Ili Dalaman Tarım Isletmesinde 1989 1996 yılları arasında yetistirilen 251 hayvana iliskin toplam 866
laktasyon verileri toplanarak degerlendirilmistir.Aylık ortalama hava sıcaklıkları dikkate alınarak iki buzagılama
mevsimi olusturulmustur. Bunlar, konfor sınırları içerisinde olan 1. buzagılama mevsimi (01 Kasım 30 Nisan) ve
2. buzagılama (01 Mayıs 31 Ekim) mevsimidir. Süt verimleri, buzagılama yılı, laktasyon sırası ve buzagılama
mevsimi degerlendirilmistir. Yapılan degerlendirmede 305 günlük süt verimine laktasyon sırası (p<0.01),
buzagılama yılı (p<0.01) ve buzagılama mevsiminin etkisi (p<0.01) önemli bulunmustur. Süt verimine iliskin 1.
ve 2. buzagılama mevsiminin en küçük kareler ortalamaları ve standart hataları sırasıyla 7493.54±70.29 kg ve
7180.63±81.08 kg olarak belirlenmistir
The effect of bovine serum albumin and fetal calf serum on sperm quality, DNA fragmentation and lipid peroxidation of the liquid stored rabbit semen
The aim of the present study was to determine the effects of the bovine serum albumin (BSA) and fetal calf
serum (FCS) on sperm quality, DNA fragmentation and lipid peroxidation of liquid stored rabbit semen
stored up to 72 h at 5 C. Ejaculates were collected from five New Zealand male rabbits by artificial vagina
and pooled at 37 C following evaluation. Each pooled ejaculate was split into three equal experimental
groups and diluted to a final concentration of approximately 40 106 sperm/ml (single step dilution),
in an Eppendorf tube, with the Tris based extender containing BSA (5 mg/ml), FCS (10%) or no additive
(control) at 37 C, cooled to 5 C and stored for up to 72 h. The extender supplemented with BSA and
FCS did not improve the percentages of motility and acrosomal abnormality during 48 h compared to
the control. The additives BSA and FCS had a significant effect in the maintaining of plasma membrane
integrity between 48 and 72 h storage period, compared to the control (P < 0.01). The supplementation
of BSA and FCS had a protective effect on motility (P < 0.05), plasma membrane integrity (P < 0.01) and
acrosomal integrity (P < 0.01) at 72 h compared to the control. The supplementations with BSA and FCS
led to a reduction in DNA damage of rabbit sperm at 48 and 72 h during storage period, compared to
the control (P < 0.001). Although supplementation of BSA and FCS caused significant (P < 0.01) decreases
in malondialdehyde (MDA) level at 48 h and 72 h, they significantly (P < 0.01) increased the glutathione
peroxidase (GPx) antioxidant activity up to 72 h when compared to the control group. In conclusion,
BSA and FCS supplementation to liquid stored rabbit semen provide a protection for spermatozoa against
cool storage-induced DNA damage and plasma membrane integrity by their antioxidative properties
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