ABSTRACT
The detection of benzonitrile (C6H5CN), 1- and 2-cyano-naphthalene (C10H7CN) in the cold, dark molecular cloud TMC-1 at centimetre (cm) wavelengths has opened up prospects for the detection ...of other N- and CN-containing polycyclic aromatic hydrocarbons (PAHs). In this light, the pure rotational spectra of N-pyrene (C15H9N), CN-pyrene (C15H9CN), N-coronene (C23H11N), and CN-coronene (C23H11CN) are reported here for the first time. The B3LYP/6-311 + G (d, p) level of theory, in the density functional theory (DFT) calculations, achieves the best performance for calculating the spectroscopic parameters and simulating the rotational spectra. The large permanent dipole moment of CN-PAHs makes them the most suitable PAH species for detection in the interstellar medium. Additionally, pyrene’s smaller partition function makes CN-pyrene a prime candidate to be discovered in cold, dark molecular clouds such as the TMC-1. The present work sets a benchmark for theoretical rotational spectra of N- and CN-containing PAHs and may act as a guide for laboratory experiments and observational searches.
This study investigates the potential of three different thermoplastic materials viz. Acrylonitrile Butadiene Styrene (ABS), High Density Polyethylene (HDPE) and Polyoxymethylene (POM) to be used in ...plastic gearing applications. The gears are manufactured by injection molding process. Thermal and wear behavior of these gears are examined at different torque levels of 0.8, 1.2, 1.6 and 2.0 Nm along with different rotational speeds of 600, 800, 1000 and 1200 rpm. Also, steady state analysis of the gears is carried out at a torque of 1.4 Nm and a rotational speed of 900 rpm to measure the reduction in the gear tooth, durability and failure modes occurring in these gears. ABS gear fails due to excessive wear of the teeth whereas HDPE gear failure is caused by the cracking at the root of gear teeth. ABS and HDPE gears complete 0.5 and 1.1 million cycles, respectively before failure whereas POM gear completes 2 million cycles without any sign of failure.
•Thermal and wear behavior of polymer based gears have been investigated.•Three different materials viz. ABS, HDPE and POM are used for manufacturing of gears.•Performance of these gears has been compared to verify their potential in gear applications.•Durability and failure modes occurring in these gears have also been investigated.
The rise in environmental concerns and pollution is largely to blame for the popularity of jute and its hybrid composites. Jute fibers are inexpensive, plentiful, and have acceptable mechanical ...characteristics such as tensile, flexural, and impact strength, along with a moderate to high tensile modulus. Environmental worries about the risks of composites made with synthetic fibers have caused an exponential growth in research into all‐natural fibers and materials. Many applications have made heavy use of jute and its hybrid composites. Hybrid jute‐based composites offer improved mechanical and physical characteristics that are marginally superior to jute fiber composites. This review includes a thorough examination of composites made of jute fiber. The main objective of this review article is to offer a critical analysis and highlight all recent advancements in jute‐based composites. The information in the article covers a variety of jute‐based composites topics, such as their chemical composition, surface treatments, mechanical and physical properties, applications, and hybrid jute‐based composites.
We investigate a field theoretical approach to the Jordan–Brans–Dicke (JBD) theory extended with a particular potential term on a cosmological background by starting with the motivation that the ...Higgs field and the scale factor of the universe are related. Based on this relation, it is possible to come up with mathematically equivalent but two different interpretations. From one point of view while the universe is static, the masses of the elementary particles change with time. The other one, which we stick with throughout the manuscript, is that while the universe is expanding, particle masses are constant. Thus, a coupled Lagrangian density of the JBD field and the scale factor (the Higgs field), which exhibit a massive particle and a linearly expanding space in zeroth order respectively, is obtained. By performing a coordinate transformation in the field space for the reduced JBD action whose kinetic part is nonlinear sigma model, the Lagrangian of two scalar fields can be written as uncoupled for the Higgs mechanism. After this transformation, as a result of spontaneous symmetry breaking, the time dependent vacuum expectation value (vev) of the Higgs field and the Higgs bosons which are the particles corresponding to quantized oscillation modes about the vacuum, are found.
With the credible detection of C
60
, C
70
and C
70
+
in the interstellar medium (ISM), new prospects have opened up for the search of other fullerenes and their derivatives. Since fullerenes show ...high proton affinities, their protonated forms should predominate in the ISM, which can easily go through deuterium enrichment. Here, we present the infrared (IR) spectra and standard enthalpy of formation of C
60
H
+
, C
60
D
+
, C
60
H
18
+
and C
60
D
18
+
using Density Functional Theory (DFT) in singly ionized forms. The obtained computed IR spectra are compared with the observations. The results show that the four mid-infrared bands of neutral C
60
are still visible in C
60
H
+
and C
60
D
+
, but their strength diminishes in C
60
H
18
+
and C
60
D
18
+
. As a conclusion, it is possible that the IR bands ascribed to C
60
are a mixture of pure and slightly protonated and deuteronated fullerenes. In this way, the observed scattering of the C
60
band ratios could be explained.
This work investigates the mechanical, fracture toughness, and thermomechanical peculiarity of a novel functionally graded materials (FGMs)–based glass fiber–filled polyamide 66 (PA66) composites. ...FGMs-based PA66 are fabricated through a particularly designed mold and a punch. Punch is a rotating element of the mold and rotates at 1800 r/min for two min for the fabrication of FGMs. Gradation of fibers takes place in FGMs toward the periphery of the punch cavity due to the centrifugal force. Neat PA66 and homogeneous composites are also fabricated through the same mold for comparative study. Punch remains stationary during the fabrication of neat PA66 and homogeneous composites. PA66 granules filled with 15 wt% and 30 wt% of glass fibers are used to manufacture FGMs and homogeneous composites. Ignition loss test, hardness measurement, and scanning electron microscope (SEM) analysis are used to verify the gradation of glass fibers within FGMs. Result analysis concluded that FGMs performed better as compared to neat PA66 and homogeneous composites. FGMs-based thermoplastic composites have full scope to fabricate polymer gears used in low load applications. This manufacturing route shows a promising potential for fabrication of FGMs-based thermoplastics which otherwise is difficult to manufacture because of their high solidification rate at room temperature.
This article proposes to develop novel functionally graded materials-based thermoplastic composites and present investigations on their mechanical and thermal properties. An especially designed mold ...and punch are used to fabricate functionally graded materials and homogeneous composites. Punch is a rotating member of the mold with a cavity at the center along the axis where the material is filled to produce desired samples. The punch rotates for 2 min at 1800 r/min for the gradation of fibers in functionally graded materials towards the outermost zone of the punch cavity. The punch is placed stationary for the fabrication of homogeneous composites. Functionally graded materials and homogeneous composites are fabricated with 15 wt.% and 30 wt.% glass fibers-reinforced polybutylene terephthalate. Neat polybutylene terephthalate is also fabricated for comparative study. The gradient of fiber distribution in functionally graded materials is verified by ignition loss test, hardness measurement, and scanning electron microscope analysis. Mechanical, fracture toughness, and thermo-mechanical peculiarity of functionally graded materials are investigated and compared with neat polybutylene terephthalate and homogeneous composites. Functionally graded materials outperform neat polybutylene terephthalate and homogeneous composites. This manufacturing technique shows a promising potential for fabrication of thermoplastics-based functionally graded materials which otherwise is difficult to produce because of their inherence characteristic to solidify at fast rate.
Polycyclic aromatic Hydrocarbons are present in the universe in varied forms and are extensively studied over the years to account for the complex natured Aromatic Infrared Bands (AIBs). As an ...abundant element in the interstellar medium, nitrogen may substitute carbon atoms in the aromatic rings of PAHs to form Polycyclic Aromatic Nitrogen Heterocyclic (PANH) molecules. These PANH molecules can have new emission features and may contribute to some of the AIBs. Extreme conditions of the ISM may support PAH and/or PANH molecules in the formation of their cationic or anionic forms to further explain the AIBs. The present work reports DFT study of PANH molecules and their ionized variants and discusses their IR spectroscopic features in the 6–10 μm region.
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