Preparation of new proton exchange membrane based on self-assembly of Poly(styrene-co-styrene sulfonic acid)-b-poly(methyl methacrylate)/Poly(vinylidene fluoride) blend

Amphiphilic block copolymers are synthesized by sulfonation of poly(styrene-b-methyl methacrylate) (PS-b-PMMA) using acetyl sulfate, and are blended with poly(vinylidene fluoride) (PVDF) to prepare a new proton exchange membrane, in which PMMA is miscible with PVDF. The morphology and the transport properties of the membranes are investigated as functions of the degree of sulfonation as well as the blend ratio. Notable transition of phase-separated morphology is observed as the PVDF content of the blend is increased. Both the proton conductivity and the ion-exchange capacity (IEC) of the membrane increase with increasing the degree of sulfonation of PS-b-PMMA, and they are also enhanced as the phase-separated domains of blend membrane are well-ordered. Unlike the Nafion membrane, the proton conductivity of the blend membrane increases up to 90 °C, indicating the blend membrane shows better thermal stability than the Nafion membrane.     

Effect of age on the myosin-V immunoreactive myenteric neurons of rats ileum.

Alterations in the gastrointestinal neuromuscular function related to age have been demonstrated in human and animal models. This study analyzes the effects of the aging process on the area of the neuronal cell bodies of the myenteric plexus in the antimesenteric and intermediate regions of the ileal circumference of Wistar, 12 month-old in comparison 3 month-old animals. The ileum was removed and whole-mount preparations immunostained by the antibody anti-myosin-V were processed. The morphometric analyses were performed using a computerized image analysis system, with a subsequent distribution of neurons by size in intervals of 100 micro2. The cellular body morphometry revealed a significant increase in the size of the myosin-V- immunoreactive myenteric neurons from 12 month-old animals when compared with 3 month-old animals. However, significant differences between the regions were not observed; these observations were not age-dependent. The implications of these results in relation to the increase of the body weight, size of the small intestine, general organization of the myenteric plexus, staining method of neurons and the possible factors involved in the regulation and/or control of the volume of neronal cells due to aging, are discussed.     

The General Solution for Affine Control Systems on Lie Groups

The purpose of this paper is to present explicitly the solution curve for commutative affine control systems on Lie groups under the assumption that the automorphisms associated with the linear vector fields commutes. If we assume that the derivations associated with the linear vector fields of the system are inner, we obtain a simpler solution and we show some results of controllability. To finish, we work with conjugation by homomorphism of Lie groups between affine systems.

     

Forecast of Adiabatic Shear Band Formation in Two Commercial Ultra-high-Strength Armor Steels by Split Hopkinson Pressure Bar

Metallurgical and Materials Transactions A - Formation possibilities of adiabatic shear bands (ASBs) or cracks in two commercial ultra-high-strength armor steels composed of martensite were...     

Object manipulation system based on image-based reinforcement learning

Intelligent Service Robotics - Advances in reinforcement learning algorithms allow robots to learn complex tasks such as object manipulation. However, most of these tasks have been implemented only...     

The influence of local development on the impact of natural disasters in Northeast Brazil: The case of droughts and floods in the state of Ceará

Using data from the Damage Assessment Reports from the Civil Defence, the current study investigates the relationship between the damage caused by natural disasters and local development at the municipality level in Ceará state, Brazil. The results show that a better urban and water supply infrastructure, a lower population density, and a higher proportion of own revenues relative to total revenues are associated with smaller disaster damage. However, economic development in terms of GDP per capita exhibits a convex relationship with the impact of natural disasters across municipalities, reflecting the potential decreasing returns of preventive investments due to the highly hazardous environment that involves municipalities.     

Evaluation of residual stresses during brazing of Al2O3-ZrO2 to cemented tungsten carbide

In the context of the assembly of a cutting tool for wood machining, this article proposes to evaluate the residual stress in a ceramic plate (Al₂O₃-ZrO₂) induced by a brazing step with a cemented tungsten carbide (WC-Co) through a brazing filler (Ag-Cu-Ti). The residual stresses were evaluated using neutron and X-ray diffraction method. Moreover, a mathematical model was used in the case of a three layer assembly, which is based on mechanical properties such as: the thermal coefficient, the Young's modulus, the Poisson's ratio and the thickness of each layer. The observation of the chemical mapping of the brazing filler before and after the assembly, using energy dispersive X-ray spectroscopy (EDX), showed the chemical migration of the titanium to the ceramic oxide and the tungsten carbide. It was estimated that the brazed assembly is under a flexural stress, with a maximum in a compressive stress area near the brazing joint which reaches 85.6 MPa. This stress value reaches 12% of the bending strength allowed by the ceramic (716 MPa). The discussion proposes to highlight the limits of each method. The mathematical model has however shown good accuracy to give a first estimated residual stress in the ceramic plate.     

Accessible software development: a conceptual model proposal

Universal Access in the Information Society - Equal access to all software and digital content should be a reality in the Digital Era. This argument is something defended both by existing...     

P-score: a reputation bibliographic index that complements citation counts

Scientometrics - The notions of reputation and popularity in academia are critical for taking decisions on research grants, faculty position tenure, and research excellence awards. These notions...