Reactive Compatibilizer Precursors for LDPE/PA6 Blends, 4

Summary: The effectiveness of some thermoplastic elastomers grafted with maleic anhydride (MA) or with glycidyl methacrylate (GMA) as compatibilizer precursors (CPs) for blends of low density polyethylene (LDPE) with polyamide‐6 (PA) has been studied. The CPs were produced by grafting different amounts of MA or GMA onto a styrene‐block‐(ethylene‐co‐1‐butene)‐block‐styrene copolymer (SEBS) (KRATON G 1652), either in the melt or in solution. A commercially available SEBS‐g‐MA copolymer with 1.7 wt.‐% MA (KRATON FG 1901X) was also used. The effect of the MA concentration and of other characteristics of the SEBS‐g‐MA CPs was also studied. The specific interactions between the CPs and the blends components were investigated through characterizations of the binary LDPE/CP and PA/CP blends, in the whole composition range. It was demonstrated that the SEBS‐g‐GMA copolymers display poor compatibilizing effectiveness due to cross‐linking resulting from reactions of the epoxy rings of these CPs with both the amine and the carboxyl end groups of PA. On the contrary, the compatibilizing efficiency of the MA‐grafted elastomers, as revealed by the thermal properties and the morphology of the compatibilized blends, was shown to be excellent. The results of this study confirm that the anhydride functional groups possess considerably higher efficiency, for the reactive compatibilization of LDPE/PA blends, than those of the ethylene‐acrylic acid and ethylene‐glycidyl methacrylate copolymers investigated in previous works.

SEM micrograph of the 75/25 LD08/PA blend (with 2 phr SEBSMA1).     

Dependence of Fluid Catalytic Cracking Unit Performance on H-Oil Severity,Catalyst Activity,and Coke Selectivity

The effect of the quality of ebullated bed vacuum residue H-Oil hydrocracking gas oils cracked in a commercial fluid catalytic cracking unit (FCCU) on its performance was studied. Six different catalysts were employed in this study. Four catalysts were tested in a commercial FCCU, and two in a laboratory FCCU. An increase of the H-Oil hydrocracker reaction temperature was associated with a decrease in the K_W factor of the H-Oil gas oils. The diminished K_W factor of H-Oil gas oils resulted in lower FCCU conversion and higher regenerator temperatures. The FCC conversion at maximum gasoline yield is best predicted by the feed K_W factor. The higher-activity, higher-Δcoke catalyst is unfavorable for FCCU performance because the excessive regenerator temperature excursions require reduction of the throughput.     

Optical properties of Nb-doped TiO2 thin films prepared by sol–gel method

In this work, we studied optical properties of pure and Nb-doped TiO₂ synthesized using a sol–gel method and deposited as thin films by spin-coating followed by annealing in air at 500 °C for 1 h. The surface elemental composition was derived from X-ray photoelectron spectra, while structure and surface morphology were investigated using X-ray diffraction and atomic force/scanning electron microscopy. Finally, the optical properties were investigated by means of UV–vis spectrophotometry and spectroscopic ellipsometry.The Nb content was determined from XPS measurements to vary between 1.8 and 4.3 at%. The XRD patterns of the deposited thin films, with a maximum thickness of about 56 nm, showed no diffraction peaks. As proven both by microscopy and spectroscopic ellipsometry studies doping TiO₂ with Nb modified the surface morphology of the samples; the grain size is increasing while the surface roughness decreases with the increase in Nb content. This is accompanied by a decrease in the refractive index and an increase of the extinction coefficient.     

Manufacturing of patterned ZnO films with application for photoinitiated decolorization of malachite green in aqueous solutions

Patterned thin films, ZnO, are successfully prepared on glass substrates by the sol-gel method using dip-coating technique. The films, formed of ZnO nanocrystallites with hexagonal crystal structure, are characterized by means of scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The as obtained ZnO films are studied with respect to photo-initiated bleaching of malachite green in aqueous solutions. The bleaching process is investigated at various initial concentrations of malachite green in the aqueous solutions by using ZnO films of different thicknesses. The obtained results are promising for the development of ZnO photocatalysts by the sol-gel method.     

Aetiology and Pathogenesis of Cutaneous Melanoma: Current Concepts and Advances

Melanoma develops from malignant transformations of the pigment-producing melanocytes. If located in the basal layer of the skin epidermis, melanoma is referred to as cutaneous, which is more frequent. However, as melanocytes are be found in the eyes, ears, gastrointestinal tract, genitalia, urinary system, and meninges, cases of mucosal melanoma or other types (e.g., ocular) may occur. The incidence and morbidity of cutaneous melanoma (cM) are constantly increasing worldwide. Australia and New Zealand are world leaders in this regard with a morbidity rate of 54/100,000 and a mortality rate of 5.6/100,000 for 2015. The aim of this review is to consolidate and present the data related to the aetiology and pathogenesis of cutaneous melanoma, thus rendering them easier to understand. In this article we will discuss these problems and the possible impacts on treatment for this disease.     

Classification of radar signatures by autoregressive model fittingand cluster analysis

Ninety radar signatures were digitally recorded during the probing of ten different land and marine objects with a pulsed coherent Doppler radar. Their spectra were evaluated on the basis of the Marple algorithm for autoregressive model fitting. An attempt at classification is made. The method consists in representing the radar signatures as points in four-dimensional space and identifying the obtained clusters of four-dimensional points with the observed objects. The cluster analysis is carried out assuming that the classification parameters have different clustering lengths     

Angiotensin Receptor-Neprilysin Inhibitor (ARNI) and Cardiac Arrhythmias

The renin-angiotensin-aldosterone system (RAAS) plays a major role in cardiovascular health and disease. Short-term RAAS activation controls water and salt retention and causes vasoconstriction, which are beneficial for maintaining cardiac output in low blood pressure and early stage heart failure. However, prolonged RAAS activation is detrimental, leading to structural remodeling and cardiac dysfunction. Natriuretic peptides (NPs) are activated to counterbalance the effect of RAAS and sympathetic nervous system by facilitating water and salt excretion and causing vasodilation. Neprilysin is a major NP-degrading enzyme that degrades multiple vaso-modulatory substances. Although the inhibition of neprilysin alone is not sufficient to counterbalance RAAS activation in cardiovascular diseases (e.g., hypertension and heart failure), a combination of angiotensin receptor blocker and neprilysin inhibitor (ARNI) was highly effective in several clinical trials and may modulate the risk of atrial and ventricular arrhythmias. This review summarizes the possible link between ARNI and cardiac arrhythmias and discusses potential underlying mechanisms, providing novel insights about the therapeutic role and safety profile of ARNI in the cardiovascular system.     

Studies on the structure and gas sensing properties of nickel–cobalt ferrite thin films prepared by spin coating

The influence of Co²⁺ ions content on structure and sensing properties of Ni_1−xCo_xFe₂O₄ (x = 0.25, 0.5, 0.75) thin films deposited on glass substrates by spin coating is presented. Structural characterization evidenced thin films with cubic spinel structures and morphologies dependent on cobalt content. Repartition of cations in spinel tetrahedral and octahedral sites was determined and was found that the presence of Co²⁺ ions in octahedral sites favor the formation of Fe²⁺ species. The sensitivity to some reducing vapor gases (acetone, liquefied petroleum gas LPG, ethyl alcohol and methyl alcohol) was investigated and was found that thin films with x = 0.75 exhibit high sensitivity to ethyl alcohol and thin films with x = 0.25 have high sensitivity to acetone. This sensitivity largely depends on the temperature and test gas concentration and was related to the Fe²⁺ species formed in octahedral sites.     

Obtaining of Ashless Additives for Diesel Fuel Impoving the Lubricating,Anticorrosion and Protection Properties

Abstract

The production of “ultra pure” diesel fuels is connected with the deterioration of their certain performance characteristics. The lubricating properties of ultra pure diesel fuels are poor; their relative stability worsens; they tend to be corrosion-aggressive toward metal surfaces; and their electrophysical properties sharply deteriorate to increase the possibilities for accumulation of static-electric charge by transportation and feeding into vehicles (Tasheva, Petkov, and Ivanov, 2003 Tasheva, J., Petkov, P. and Ivanov, Sl. 2003. Contemporary trends in connection with the reduction of sulfur oxides at burning of fuels. Annual of University Prof. Dr. Assen Zlatarov, Bourgas, Bulgaria, XXXII(1): 150–155.  [Google Scholar]; 2004 Tasheva, J., Petkov, P. and Ivanov, Sl. 2004. Reduction of the contents of sulphur-containing organic compounds, arene hydrocarbons and resinous products in diesel fuels by applying extraction with selective solvents. Oxidation Communications, 27(1): 48–57.  [Google Scholar]).

These negative properties of the ultra pure diesel fuel are usually overcome by adding special substances to improve their lubricating properties, electric conductivity, and oxidation stability and to eliminate their corrosion aggressiveness.