Search results for "LIMIT"
showing 10 items of 2826 documents
Optimization of continuous elastic perfectly plastic beams
2004
Abstract The optimal design of elastic plastic beams subjected to loads quasi-statically variable within a given domain is studied. A minimum volume formulation and a maximum load multiplier formulation are developed, both expressed on the grounds of a statical as well as of a kinematical approach. The search problems are formulated according to three different limiting criteria acting simultaneously. For each criterion a corresponding selected safety factor is imposed. The Euler–Lagrange equations related to the above described problems are deduced. A special iterative technique devoted to the solution of the above referenced problems is proposed. Some numerical examples conclude the paper.
Fixed strength and stiffness hinges for steel frames
2017
A new type of device able to connect steel beam elements is proposed. Specifically, the device is designed in such a way that the required bending stiffness and limit resistance can be independently imposed. To this goal, the device is realized as a "sandwich" section whose wings possess a particular geometry able to guarantee the required characteristics. Further technological requirement is that the device has to engage plan dimensions equal to those of the elements to which it is connected. The procedure to design the device is presented in the paper with reference to a simple plane steel portal constituted by appropriate profiles in such a way it behaves following an assigned force/disp…
Minimum volume design of structures with constraints on ductility and stability
2014
Abstract A minimum volume design problem of elastic perfectly plastic frame structures subjected to different combinations of fixed and seismic loads is presented, in which the design variables are considered as appertaining alternatively to a continuous assigned range as well as to appropriate discrete sets. The structure is designed so as to behave elastically for the applied fixed loads, to shakedown in presence of serviceability seismic conditions and to prevent the instantaneous collapse for suitably chosen combinations of fixed and high seismic loadings. In order to avoid further undesired collapse modes, the P-Delta effects are considered and the structure is also constrained to prev…
A generalized model of human body radiative heat exchanges for optimal design of indoor thermal comfort conditions
2018
Abstract Human thermal sensation depends heavily on radiative exchanges between the human body and the surrounding environment. Because these exchanges play a crucial role in the thermal balance of the human body, about 35% of the process, human thermal sensation should draw the attention of planners when designing both indoor environments and equipment. The present study aims to contribute to this field by proposing a procedure for delineating the optimal comfort conditions for occupants in most of the articulate and realistic configurations of actual indoor environments. Specifically, this procedure enables accurate assessment of the radiant field surrounding a subject in a given indoor r…
Knowledge construction about port performance evaluation: An international literature analysis
2017
Purpose: This study aims to identify and analyze the characteristics of international scientific research that addresses the segment of literature referring to port performance evaluation, in order to identify the existence of a theoretical alignment between the concept of performance evaluation, as an area of knowledge, and the practical application of port performance evaluation. Design/methodology: For the approach to the problem, this paper makes use of qualitative research, analyzing bibliographical portfolio characteristics related to port performance evaluation. An action research strategy was adopted, according to which the authors selected the bibliographical portfolio based on ana…
Why is the hypothetico-deductive (H-D) method in information systems not an H-D method?
2020
Abstract The hypothetico-deductive (H-D) method is reported to be common in information systems (IS). In IS, the H-D method is often presented as a Popperian, Hempelian, or natural science method. However, there are many fundamental differences between what Popper or Hempel actually say and what the alleged H-D method per Hempel or per Popper means in IS. To avoid possible misunderstanding and conceptual confusion about the basic philosophical concepts, we explain some of these differences, which are not mentioned in IS literature describing the H-D model. Due to these distinctive differences, the alleged H-D method per Hempel or per Popper in IS cannot be regarded as the H-D model per Hemp…
Supination control increases performance in sideward cutting movements in tennis.
2013
The objective of this study was to explore the effects of tennis shoe characteristics on performance during sideward cutting movements followed by direction changes. Five tennis players (age = 21.5 +/- 0.8 years, mass = 75.2 +/- 2.8 kg, and height = 1.78 +/- 0.05 m) participated in the study and 10 tennis shoes were tested. Several footwear mechanical parameters were analyzed: Shore A hardness, longitudinal and transverse flexibility, midsole height at heel, presence of heel counters, and weight. A force plate was used to measure the kinetic variables, and two video cameras were used to perform a three-dimensional photogrammetric analysis. Results revealed that subject-footwear interaction …
Kinetic Monte Carlo modeling of Y2O3 nano-cluster formation in radiation resistant matrices
2018
This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.
Selective and sensitive colorimetric detection of the neurotransmitter serotonin based on the aggregation of bifunctionalised gold nanoparticles
2018
[EN] We report a simple, sensitive and selective method for the colorimetric detection of serotonin (5-HT) in aqueous media using bifunctionalized gold nanoparticles (AuNPs). The probe (1) consisted of AuNPs functionalised with dithiobis(succinimidylpropionate) (DSP) and N-acetyl-l-cysteine (NALC). DSP was chosen to react with the amino group of 5-HT, whereas NALC was chosen to bind the hydroxyl group in 5-HT through hydrogen bonding and electrostatic interactions. A double interaction between nanoparticles and the hydroxyl and the amino group of serotonin led to interparticle-crosslinking aggregation. This, resulted in a colour change from red to blue that can be observed by the naked eye.…
Colorimetric detection of normetanephrine, a pheochromocytoma biomarker, using bifunctionalised gold nanoparticles.
2019
[EN] A simple and effective colorimetric method for the detection of normetanephrine (NMN), an O-methylated metabolite of norepinephrine, using functionalised gold nanoparticles is described. This metabolite is an important biomarker in the diagnosis of adrenal tumours such as pheocromocytoma or paraganglioma. The colorimetric probe consists of spherical gold nanoparticles (AuNPs) functionalised with two different ligands, which specifically recognize different functional groups in normetanephrine. Thus, a benzaldehyde-terminated ligand was used for the recognition of the amino alcohol moiety in NMN, by forming the corresponding oxazolidine. On the other hand, N-acetyl-cysteine was chosen f…