EFFECTS OF TEMPERATURE ENVIRONMENT ON MODE II INTERLAMINAR FRACTURE TOUGHNESS IN ASYMMETRIC CFRP LAMINATES

When delamination occurs in CFRP laminates due to impact, a portion of the laminate structure becomes asymmetric across the delamination in the thickness direction, resulting in a coupling effect of in-plane and out-of-plane deformations. Thus, it is important to evaluate the coupling effects on the interlaminar fracture toughness and fracture mechanism in CFRP laminates. In addition, it is necessary to withstand practical temperature environments. Based on Verchery's approach, the authors intentionally prepared asymmetric laminates with non-zero and zero-coupling components in the classical lamination theory to evaluate the effects of coupling components on the interlaminar fracture toughness in CFRP laminates. In this study, the Mode II interlaminar fracture toughness of CFRP laminates with and without coupling components in the stiffness matrix was measured by the end notched flexure (ENF) test in the temperature range from room temperature to 80°C. The relationship between the temperature and the interlaminar fracture toughness was quantitatively evaluated. Fracture surface observation was also conducted to clarify the fracture mechanism.

Disazo (Bishydrazone) pigments based on acetoacetanilides

Disazoacetoacetanilide pigments, more commonly known as diarylide yellows, are the most important group of yellow classical organic pigments. They were commercialized in the early 20th century many years after the introduction of the structurally related monazoacetoacetanilides (Hansa yellows). The molecules adopt the bis-ketohydrazone tautomeric form. X-ray single crystal structure investigations have provided an insight into the influence of the molecular geometry and crystal packing arrangements in the solid state on the properties of the pigments in application. The synthesis of diarylide pigments is relatively straightforward, the conditions essentially following those used for the corresponding monoazo pigments, so that the products are economically priced. In the case of these disazo pigments, suitable aromatic amines (1 mol) are bis-diazotized and the resulting bis-diazonium salts reacted with acetoacetanilide coupling components (2 mol), the two azo coupling reactions occurring at the same time. They are by far the dominant group of yellow pigments used in printing inks, well-suited for most standard process yellow inks. They were formerly important in the coloration of plastics but are no longer recommended for polymers processed above 200 °C, under which conditions toxic decomposition products are formed. Diarylide yellow pigments are characterized by high color strength, good to excellent solvent fastness, and good chemical stability, although they generally show inferior lightfastness.

Monoazo (Monohydrazone) pigments based on 2-naphthol and derivatives

This chapter describes the range of industrial monoazo pigments based on the 2-naphthol (β-naphthol) ring system. This group includes some of the earliest organic pigments introduced commercially and is also numerically the largest group of products currently described in the Colour Index. Most of the pigments within this group are red (with a few oranges), thus complementing the azoacetoacetanilides, which are mostly yellows. Three groups of monoazonaphthol-based pigments may be identified categorized according to the chemical structure of the coupling components used in their synthesis. The first group contains products based on 2-naphthol itself, a second is based on amide derivatives of 3-hydroxy-2-naphthoic acid (naphtharylamides), and the third is a series of metal salt azo pigments. The historical development of these pigments, outlined in an early section of this chapter, originated in the late 19th century with pigments described as ‘lakes’, derived from water-soluble anionic dyes absorbed on to inert colorless substrates, which were the forerunners of products now referred to as metal salt pigments. The non-ionic 2-naphthol-based pigments were introduced soon after. In the early to mid-20th century, a series of monoazonaphtharylamide (Naphthol AS) pigments were developed and introduced commercially. The pigments of this type that are currently manufactured can be sub-divided into products containing a single amide group (group 1) and higher performance products containing more than one amide or sulfonamide groups. Several group 1 pigments have diminished in importance over the years, while some higher performing group 2 pigments have grown in importance. The molecular and crystal structures of the range of pigments are presented and discussed in relation to their performance characteristics. The manufacture of the pigments involves the reaction of a diazotized aromatic amine with the appropriate 2-naphthol-based coupling component, using synthesis conditions typical of phenolic coupling components, followed by conditioning aftertreatments that are typical for azo pigments in general. Finally, there is an extensive discussion of the wide-ranging applications in which the individual pigments are used. While the pigments are especially well-suited to printing ink applications, many products also find use in paints and a few in plastics.

Disazo (Bishydrazone) pigments based on pyrazolones

The most important classical orange organic pigments are disazopyrazolones, also referred to as diarylide oranges. The first pigment in this series, CI Pigment Orange 13, was discovered in 1910 although it was a further 20 years before it was introduced as a commercial product. Currently, two orange disazopyrazolones are extremely important industrial organic pigments, while two red products are of lesser importance. The products are structurally analogous to the disazoacetoacetanilides (diarylide yellows), which are discussed in a separate chapter. For example, they are symmetrical compounds that exist in the bis-ketohydrazone tautomeric form. The pigments also exhibit similar technical and color properties compared with disazoacetoacetanilide pigments, for example providing high color strength and transparency, features that determine their importance as printing ink pigments. They are manufactured in a process that parallels those used for the disazoacetoacetanilide (diarylide) yellows, but with coupling components containing the pyrazolone heterocyclic system, in place of acetoacetanilides.

Spectral Imaging Experiments with Various Optical Schemes Based on the Same AOTF

Spectral image filtration by means of acousto-optical tunable filters (AOTFs) has multiple applications. For its implementation, a few different optical schemes are in use. They differ in image quality, number of coupling components, dimensions and alignment complexity. To choose the optical system of AOTF-based spectral imager properly, many factors have to be considered. Though various schemes of acousto-optic (AO) filtration have been tested and discussed, their comparative analysis has not been reported up to now. In this study, we assembled the four most popular schemes (confocal, collimating, tandem and double-path) using the same AO cells and experimentally compared their main features. Depending on the application, each scheme may be the basis of compact cost-effective spectral imaging devices.

Multitask ATPases (NBDs) of bacterial ABC importers type I and their interspecies exchangeability

ATP-binding cassette (ABC) type I importers are widespread in bacteria and play a crucial role in its survival and pathogenesis. They share the same modular architecture comprising two intracellular nucleotide-binding domains (NBDs), two transmembrane domains (TMDs) and a substrate-binding protein. The NBDs bind and hydrolyze ATP, thereby generating conformational changes that are coupled to the TMDs and lead to substrate translocation. A group of multitask NBDs that are able to serve as the cellular motor for multiple sugar importers was recently discovered. To understand why some ABC importers share energy-coupling components, we used the MsmX ATPase from Bacillus subtilis as a model for biological and structural studies. Here we report the first examples of functional hybrid interspecies ABC type I importers in which the NBDs could be exchanged. Furthermore, the first crystal structure of an assigned multitask NBD provides a framework to understand the molecular basis of the broader specificity of interaction with the TMDs.

Evaluation of Antibacterial Potential of New Acid Dyes Based on Substituted Aryl Amines and Amino Hydroxy Sulfonic Acid

Six newly synthesized acid dye derivatives were evaluated for their in vitro antimicrobial activity against four (04) Gram positive (Staphylococcus aureus, Staphylococcus lugdunensis, Streptococcus pneumoniae and Bacillus subtilis) and six (06) Gram negative (Pseudomonas aeruginosa, Acinetobacter baumannii, Citrobacter freundii, Klebsiella pneumoniae,Pseudomonas fluorescens and Shigella sonnei) bacterial strains. The dyes were synthesized using substituted aryl amines and substituted amino hydroxy sulfonic acid as diazo and coupling components, respectively. The antimicrobial activity was explored by Agar-Well Diffusion method using 100 mg/ml dye concentration. The results demonstrated that the dyes possess varying degrees of activities against the bacterial strains tested and the structure of the dye molecules was found to have considerable influence on their antimicrobial activity.

In situ engineered ZnS–FeS heterostructures in N-doped carbon nanocages accelerating polysulfide redox kinetics for lithium sulfur batteries

Building heterostructures containing dissimilar coupling components with different bandgaps can promote interfacial reaction kinetics and accelerate charge carrier transport for Li–S batteries.