Evaluation of the thermomechanical properties of novel epoxy composites reinforced with Geonoma baculifera fibers.

Natural lignocellulosic fibers (NLFs) have shown a great potential as reinforcements in composites in recent decades. Among other reasons, environmental concerns and the depletion of oil reserves justify research on natural composites as they offer an environmentally friendly alternative and align with the principles of sustainable development. Among the plethora of NLFs available in nature, the ubim fiber (Geonoma baculifera) has not yet been investigated as a reinforcement for composites in potential engineering applications.

Impact of Different Mineral Reinforcements on HDPE Composites: Effects of Melt Flow Index and Particle Size on Physical and Mechanical Properties.

The use of mineral reinforcements in polymer matrix composites has emerged as an alternative for sustainable production, reducing waste and enhancing the physical and mechanical properties of these materials. This study investigated the impact of the melt flow index (MFI) of HDPE and the particle size of two mineral reinforcements, Bahia Beige (BB) and Rio Grande do Norte Limestone (CRN), on the composites. All composites were processed via extrusion, followed by injection, with the addition of 30 wt.

A soluble model for synchronized rhythmic activity in ant colonies.

Synchronization is one of the most striking instances of collective behavior, occurring in many natural phenomena. For example, in some ant species, ants are inactive within the nest most of the time, but their bursts of activity are highly synchronized and involve the entire nest population. Here we revisit a simulation model that generates this synchronized rhythmic activity through autocatalytic behavior, i.

Neuroleptic Malignant Syndrome: An Intensive Care Unit Case of Exceptionally High Creatinine Kinase and Myoglobin Levels.

Neuroleptic Malignant Syndrome (NMS) is a rare, life-threatening neurologic emergency known to be related to the administration or sudden withdrawal of dopaminergic medications. The clinical course, symptoms, and bloodwork are very heterogeneous, making this syndrome difficult to identify. Thus, NMS is a diagnosis of exclusion.

Babassu Coconut Fibers: Investigation of Chemical and Surface Properties (.).

To complement previous results, an analysis of the chemical and morphological properties of babassu fibers (.) was conducted in order to evaluate their potential as reinforcements in the production of composites with epoxy matrix. The diameter distribution was analyzed in a sample of one hundred fibers, allowing the verification of its variation.

Characterization of Thermo-Mechanical and Chemical Properties of Polypropylene/Hemp Fiber Biocomposites: Impact of Maleic Anhydride Compatibilizer and Fiber Content.

This article presents a comprehensive study on the physical, mechanical, thermal, and chemical properties of polypropylene (PP) composites reinforced with hemp fibers (HF) and compatibilized with maleic anhydride (MAPP). The composites were processed using a twin-screw extruder, followed by hot compression at 190 °C. Subsequently, the composites were analyzed using Izod impact and Shore D hardness tests to evaluate their mechanical properties.

Ballistic Performance, Thermal and Chemical Characterization of Ubim Fiber () Reinforced Epoxy Matrix Composites.

The search for unexplored natural materials as an alternative to synthetic components has driven the development of novel polymeric composites reinforced with environmentally-friendly materials. Natural lignocellulosic fibers (NLFs) have been highlighted as potential reinforcement in composite materials for engineering applications. In this work, a less known Amazonian fiber, the ubim fiber (), is investigated as a possible reinforcement in epoxy composites and was, for the first time, thermally characterized by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC).

Acute Cocaine Intoxication: An Approach to Severe Hepatic and Renal Dysfunctions.

Cocaine is a highly addictive substance. Its poisoning can lead to potentially fatal multi-organ dysfunction. We report a case of cocaine overdose with severe multi-organ dysfunction.

Polymeric nanoparticles containing babassu oil: A proposed drug delivery system for controlled release of hydrophilic compounds.

Different drug delivery systems are prepared on the nanoscale to improve performance in drug formulations, such as nanoparticles or nanoemulsions. Polymeric nanoparticles have been used to encapsulate drugs for several applications because of some characteristics of these carriers to control drug delivery, transport molecules to a specific tissue, protect the drugs, and increase drug bioavailability. When using nanocapsules, an essential parameter for encapsulating different hydrophilic or lipophilic molecules is the characteristics of the core.

Fabric Impregnation with Shear Thickening Fluid for Ballistic Armor Polymer Composites: An Updated Overview.

As destructive power of firearms raises over the years, ballistic armors are in continuous need of enhancement. For soft armors, this improvement is invariably related to the increase of stacked layers of high-strength fiber fabrics, which potentially restrains wearer mobility. A different solution was created in the early 2000s, when a research work proposed a new treatment of the ballistic panels with non-Newtonian colloidal shear thickening fluid (STF), in view of weight decreasing with strength reinforcement and cost-effective production.

Mechanical Properties, Critical Length, and Interfacial Strength of Seven-Islands-Sedge Fibers () for Possible Epoxy Matrix Reinforcement.

The growing concern about the limitation of non-renewable resources has brought a focus on the development of environmentally sustainable and biodegradable composite materials. In this context, a trend in the development of natural fibers used as a reinforcement in composites is ever-increasing. In this work, for the first-time, fibers extracted from the seven-islands-sedge plant () have been characterized by X-ray diffraction (XRD) to calculate the crystallinity index and the microfibrillar angle (MFA).

Curaua-Aramid Hybrid Laminated Composites for Impact Applications: Flexural, Charpy Impact and Elastic Properties.

Curaua, as a leaf-based natural fiber, appears to be a promising component with aramid fabric reinforcement of hybrid composites. This work deals with the investigation of flexural, impact and elastic properties of non-woven curaua-aramid fabric hybrid epoxy composites. Five configurations of hybrid composites in a curaua non-woven mat with an increasing quantity of layers, up to four layers, were laminated through the conventional hand lay-up method.

Evaluation of the Change in Density with the Diameter and Thermal Analysis of the Seven-Islands-Sedge Fiber.

Basic properties of sedge fibers from the seven-islands-sedge plant () were investigated with possible application in reinforcing composite materials. A dimensional distribution and the effect of fiber diameter on density were investigated using gas pycnometry. The Weibull method, used to statistically analyze the acquired data from the diameter intervals, indicated an inverse dependence, where the thinnest fibers had the highest density values.

Dynamic Mechanical Analysis and Ballistic Performance of Kenaf Fiber-Reinforced Epoxy Composites.

Several industry sectors have sought to develop materials that combine lightness, strength and cost-effectiveness. Natural lignocellulosic natural fibers have demonstrated to be efficient in replacing synthetic fibers, owing to several advantages such as costs 50% lower than that of synthetic fibers and promising mechanical specific properties. Polymeric matrix composites that use kenaf fibers as reinforcement have shown strength increases of over 600%.

Bio-Based Composites for Light Automotive Parts: Statistical Analysis of Mechanical Properties; Effect of Matrix and Alkali Treatment in Sisal Fibers.

Composites based on virgin and recycled polypropylene (PP and rPP) reinforced with 15 wt% sisal fibers, with and without alkali treatment, were prepared by compression molding in a mat composed of a three-layer sandwich structure. The sisal was characterized by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The composites were characterized according to physical and mechanical properties.

Tensile Properties of Curaua-Aramid Hybrid Laminated Composites for Ballistic Helmet.

A typical ballistic protection helmet for ground military troops has an inside laminate polymer composite reinforced with 19 layers of the aramid, which are neither recyclable or biodegradable and are relatively expensive. The hybridization of synthetic aramid with a natural lignocellulosic fiber (NLF) can provide a lower cost and desirable sustainability to the helmet. In the present work, the curaua fiber, one of the strongest NLFs, is, for the first time, considered in non-woven mat layers to partially replace the aramid woven fabric layers.

Flexural Strength of Vitreous Ceramics Based on Lithium Disilicate and Lithium Silicate Reinforced with Zirconia for CAD/CAM.

The dental prosthesis market is rapidly evolving to meet patient and clinical demands. These new materials must have good flexural strength, toughness, aesthetic properties, and reliability in performance for structural applications. The present work aimed to compare the bending strength of 4 types of chairside lithium disilicate (LiSiO) glass-ceramics used for dental prosthesis and to analyze the influence of heat treatment on the transformation of lithium metasilicate (LiSiO) into lithium disilicate.

Thermal and Chemical Characterization of Kenaf Fiber () Reinforced Epoxy Matrix Composites.

Kenaf () is one of the most investigated and industrially applied natural fibers for polymer composite reinforcement. However, relatively limited information is available regarding its epoxy composites. In this work, both thermal and chemical properties were, for the first time, determined in kenaf fiber reinforced epoxy matrix composites.

First record of Burkholderia mallei Turkey 10 strain originating from glanderous horses from Brazil.

Burkholderia (B.) mallei is the causative agent of glanders in Equidae. This study describes the first record of the Turkey 10 strain of B.

Intrafollicular paraoxonase 1 activity and the steroidogenic potential of the first post-partum dominant follicle in dairy cows.

Cows experiencing high levels of inflammation and specific metabolic conditions tend to have slower follicular growth and lower serum and follicular concentrations of oestradiol (E2). Paraoxonase1 (PON1) activity decreases during inflammatory processes. Therefore, the aim of this study was to evaluate the association between serum and intrafollicular (FF) PON1 activity and the serum and intrafollicular levels of E2 and progesterone (P4), as well as the mRNA expression of genes related to steroidogenesis, metabolism and inflammation in the first post-partum dominant follicle of Holstein cows.