Jai N. Dahiya

MICROWAVE ENHANCED POLARIZATION IN A CARBON DIOXIDE MOLECULE

In this paper we present the results of the dielectric response of Carbon Dioxide measured using a loaded microwave cavity operating in the TE mode of a cylindrical cavity near the frequencies 8.8, 9.7 and 10.2 GHz. The temperature dependence of the dielectric response of gas phase CO2 over the range of 160 to 213°K (-113 to -60° C) was measured. Slater perturbation equations for loaded resonant cavities were used to relate the macroscopic parameters ▵f and ▵(1/Q) to the real and imaginary parts, ε and ε”, respectively, hence to calculate the dielectric parameters at each temperature and frequency. Selected peaks in the dielectric response were identified to indicate the frequencies at which strong coupling between the microwave field and the CO2 molecules can be achieved.

Functionalized Nanomaterials to Sense Toxins/Pollutant Gases Using Perturbed Microwave Resonant Cavities

This chapter provides an overview of the techniques and methods involving electromagnetic resonators to study the interactions of gas molecules with nanomaterials substrates. A resonant cavity operating in TE011 mode was employed by the author(s) to characterize the nature of interactions of a range of weakly polar to nonpolar gas molecules with carbon nanotubes loaded in the cavity. Microwave resonant cavities are special electromagnetic resonators that can have a very high quality factor, which enhances the sensitivity of the apparatus as compared to standard electrical tank circuits. By measuring shifts in the resonant frequency of these circuits and by calculating the pressure broadening of the resonant peaks, the technique developed offers a highly effective means to quantify the amount of foreign agents perturbing these resonant cylinders. By functionalizing the nanomaterials with specific antibodies and loading them as wicks in these cylinders, the technique can be engineered into a very sensitive and unique chemical and biological sensor prototype.

Interface science and engineering for less friction and wear

Friction is the resistance against motion. It is an obvious phenomenon whenever a solid body moves over another. At the interface of moving surfaces, solid–solid and solid–fluid interactions take place and generate frictional heat. This frictional heat not only changes the physical and chemical nature of the interacting surfaces but also their topography. The wear and energy loss are the derivatives of friction. This wear is the main cause of concern for leading maintenance and repair issues involving various machine components like brakes, clutches, gear boxes and so on. Thus, the reduction of friction and wear is essential in enhancing service life and lowering expenditure, which could potentially lead to significant operational cost reduction. Therefore, the study of interface phenomenon and surface characteristics is crucial in obtaining a better and stronger performance from every moving element. Recent technological advancements enable us to explore these interface phenomena and surface properties within various domains, ranging from the atomic and molecular to the microand nano-scale. This micro-/nano-scale level of understanding bridges the gap between science and engineering methods, in addition to furnishing the knowledge required for the optimal design of various materials and components for technological applications. Interface science and engineering thereby play a pivotal role in every facet of daily life, spanning from live cell friction to engine lubrication. The central theme of this special issue is geared towards tailoring surface and interface elements to reduce friction and wear and consequently obtain better moving surfaces. The main goal of this special issue is to provide an overview of current state-of-the art techniques for new material development, in order to obtain superior surface finish as well as stronger wear resistance properties, advancements in contact phenomenon modelling at micro-/nano-scale, and exploration of newer lubricants, additives and coatings for enhanced surface protection. With these motivations and needs, this special issue covers recent research and developments on interface science and engineering and its application to the various sliding components like mechanical seals and winding hoisting ropes, as well as modelling and simulation of contact. We would like to thank all the authors for their valuable contributions to this special collection. We are also grateful to the referees for their time and valuable comments and suggestions which have further enriched the quality of the articles for this special collection.

Polarization rotation by multilayered helix metamaterial

Quasi-3D helix metamaterial is constructed from multilayered 2D spiral structure with capacitive coupling between the adjacent layers. The sample is implemented with PCB, and linearly polarized microwave source is used in the measurement. The polarization plane is rotated to the opposite directions with left- and right-handed samples. The ratio of rotation angles is consistent with theoretical prediction.

Polarization rotation by helix metamaterial

This paper investigates the polarization rotation effect of metamaterial with a lattice of flattened spiral segments. This multilayered structure can be fabricated easily, and the simulation result shows that it can rotate the polarization effectively.

Microwave initiated atomic spectra from select atomic species.

Abstract Isotopes of gaseous Helium (3He and 4He) were admitted into the vacuum system at various pressures and allowed to stabilize. Quantum states were then energized using a 2.45 GHz magnetron coupled to the gases by loose coupling. A residual gas analyzer Model 100 series manufactured by Stanford Research Systems was used to determine the mass of each species. An Ocean Optics Optical Spectrometer model collecting the light via an optic probe was used to obtain the spectra and to characterize the spectroscopic peaks. The data collected from these isotopes represent characteristic spectral emission lines generated due to the transitions among discrete quantum energy levels. The data analysis, especially for atomic spectroscopy, becomes an extremely important tool in developing an understanding of the quantum levels active within each atom. In this paper is presented a summary of the analysis of work that was done on two isotopes of helium. Data using both computational as well as theoretical techniques are presented. Traditional high voltage arc discharge data were taken for the gas species and these are compared with microwave stimulated atomic emissions.