Modelo numérico del comportamiento histerético de uniones entre forjados reticulares y pilares de fachada

Waffle-flat-plate structures have been widely used for residential and office buildings in the South of Europe between the seventies and nineties of the last century. These buildings were designed with old seismic codes and its vulnerability needs to be evaluated to determine whether they need to be seismic retrofitted or not. This article proposes a simple model that represents the moment transfer between plate and column, for existing exterior connections loaded in the direction normal to the building façade. The model takes into account singularities of existing waffle-flat-plate structures such as the concentration of reinforcement in the direction of the joints, and the existence of punching shear reinforcement. The model consists of frame elements for the columns and shell elements for the slabs, both connected with flexural and torsion hinges. The strength of the flexural hinges is obtained by estimating the portion of longitudinal reinforcement of the plate that transfers directly the unbalanced moment to the column by flexure. The yielding deformations of the flexural and torsion hinges are estimated with simple expressions. The ductility of the flexural hinges is taken from FEMA 356, while infinite ductility is adopted for the torsional hinges in accordance with previous experimental studies. It is shown that the proposed model provides a good approximation of the experimental response of the connection under monotonically increasing lateral displacements, in terms of stiffness, strength and ductility.     

Synthesis of All Stereoisomers of Monomeric Spectomycin A1/A2 and Evaluation of Their Protein SUMOylation-Inhibitory Activity

A synthetic methodology to access all possible stereoisomers of spectomycin A1 (SMA1) and A2 (SMA2) has been established through late-stage diversification. The key reaction for the construction of all four diastereomers is an intramolecular cyclization based on the umpolung of π-allyl palladium species with bis(pinacolato)diborane (B₂(pin)₂). Silyl group assisted direct benzylic oxidation of each isomer enabled construction of the fragile β-hydroxytetralone skeleton to provide the SMAs. The relative and absolute stereochemistry of SMA2 was also determined, and the absolute stereochemistry of SMA1 was extrapolated based on the optical rotation of SMA2. The axial chirality of SMAs is discussed based on circular dichroism spectra and DFT calculations, and it is concluded that the M isomer is predominant in solution. Biochemical assessment of all isomers in vitro revealed that the C9 hydroxyl group and dimeric structure were both important for protein SUMOylation-inhibitory activity.     

Operation and preventive maintenance scheduling for containerships: Mathematical model and solution algorithm

This paper considers the problem of determining operation and maintenance schedules for a containership equipped with various subsystems during its sailing according to a pre-determined navigation schedule. The operation schedule, which specifies working time of each subsystem, determines the due-date of each maintenance activity and the maintenance schedule specifies the actual start time of each maintenance activity. The main constraints are subsystem requirements, workforce availability, working time limitation, and inter-maintenance time. To represent the problem mathematically, a mixed integer programming model is developed. Then, due to the complexity of the problem, we suggest a heuristic algorithm that minimizes the sum of earliness and tardiness between the due-date and the actual start time for each maintenance activity. Computational experiments were done on various test instances and the results are reported. In particular, a case study was done on a real instance and a significant amount of improvement is reported over the experience based conventional method.     

Synthesis and enantiomeric recognition studies of a novel 5,5-dioxophenothiazine-1,9 bis(thiourea) containing glucopyranosyl groups

A novel optically active 5,5-dioxophenothiazine-1,9 bis(thiourea) containing glucopyranosyl groups was synthesized and its enantiomeric recognition properties were examined towards the enantiomers of tetrabutylammonium salts of chiral α-hydroxy and N-protected α-amino acids using UV–vis spectroscopy.     

W-shaped mesogens and variations of their molecular structure

New bent-core liquid crystalline dimers with W-shaped molecular geometry have been prepared and studied. We have modified the dimer shape by variation of the connecting part between two bent-core units and changing the terminal chains (perfluoroalkyl, siloxanealkyl). Additionally, we have altered the inner bend angle value (120°, 60° and 148°) by utilization of different aromatic units. Mesomorphic properties of new dimers were established based on the texture observation in the polarizing microscope and DSC measurements. Moreover, x-ray structural analysis has been performed for selected dimers to confirm phase identification. For most of the studied dimers, nematic or columnar phases have been detected, for several compounds appearing in a nematic-columnar phase sequence on cooling from the isotropic phase. The studied dimers showed richer polymorphism than their monomeric counterparts.     

Photooptical Properties of Polymethacrylates Having Cyanoazobenzene‐Containing Side Groups with Lateral Methyl Substituents and Different Spacer Length

New photochromic polymethacrylates with different spacer length having azobenzene side groups and lateral methyl substituents were synthesized. The phase behavior of polymethacrylates and their photooptical properties were studied and compared with unsubstituted analogues. It is shown that an introduction of lateral methyl substituents results in almost complete suppression of liquid crystalline (LC) phase formation and strong decrease of photoinduced dichroism values. It is found that rates of the photoinduced E‐Z isomerization and back thermal Z‐E isomerization are almost independent on spacer lengths. Due to the presence of lateral substituents, the photoinduced azobenzene Z‐form shows remarkable long lifetime, and back thermal conversion at room temperature takes more than 10 days. Specific peculiarities of the photoorientation process in polymer films under the polarized UV and visible light action were studied and their mechanism is suggested. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1337–1342     

Optimizing the Electricity Consumption with a High Degree of Flexibility Using a Dynamic Tariff and Stackelberg Game

Journal of Optimization Theory and Applications - Recent advancements in the sensor industry, smart metering systems and communication technology have led to interesting electricity consumption...