Zeolites: An Emerging Material for Gas Storage and Separation Applications

Zeolites are one of the amazing materials available in nature because of their structural pores. Interestingly, these god-gifted properties of zeolite can be used in gas separation and storage application. Actually, hydrogen separation and its storage are now a thrust research area. Hydrogen is considered as a ‘clean energy,’ which is indispensable for global affluence and alternative energy for future. But hydrogen is not accessible in its pure form during the industrial synthesis process and comes out with some other impurities like CO2 (GHG) and other gases. So, the production of carbon-free hydrogen and its storage is so much vital. In conventional technologies, few concerns are always existed during gas separation and also in storage process. Recently, membrane-based separation process is a highly demanding technology in the industry and shows some advantages as compared to conventional process. Based on this concept, in this chapter, three different types of zeolites, that is, DDR, SAPO 34, and Bikitaite are highlighted. Here, we described the advanced synthesis process and the mechanism towards the development of high-quality nearly defect-free membranes on cheaper support. Finally, the evaluation of membranes is described through gas permeation and selectivity results of different single gas and mixture gas composition. In addition, storage capacity of H2 by zeolite/surface-modified zeolites is included in this chapter

Interplay between quantum Zeno and anti-Zeno effects in a non-degenerate hyper-Raman nonlinear optical coupler

Quantum Zeno and anti-Zeno effects are studied in an asymmetric nonlinear optical coupler composed of a probe waveguide and a system waveguide. The system is a nonlinear waveguide operating under non-degenerate hyper-Raman process, while both the pump modes in the system are constantly interacting with the probe waveguide. The effect of the presence of probe on the temporal evolution of the system in terms of the number of photons in Stokes and anti-Stokes modes as well as phonon number is quantified as Zeno parameter. The negative (positive) values of the Zeno parameter in the specific mode are considered as the signatures of the quantum Zeno (anti-Zeno)effect in that mode of the system. It is observed that the phase mismatch in Stokes and anti-Stokes generation processes can be controlled to induce a transition between quantum Zeno and anti-Zeno effects for both off-resonant and resonant hyper-Raman process. However, in case of off-resonant hyper-Raman process in the system waveguide, the frequency detuning parameters can also be used analogously to cause the desired crossover. Further, the general nature of the physical system and the perturbative technique used here allowed us to analytically study the possibilities of observing quantum Zeno and anti-Zeno effects in a large number of special cases, including situations where the process is spontaneous, partially spontaneous and/or the system is operated under degenerate hyper-Raman process, or a simple Raman process.Comment: Dynamics of quantum Zeno and anti-Zeno effect is studied analytically in a nonlinear optical coupler which is very general in natur

Briquetting of Iron Bearing Materials

This study deals with the recycling of the solid waste materials such as iron fines, mill scale, etc. for the efficient use in the blast furnace operations. The recycling of the materials causes improvement in the economic conditions of the industries and environmental conditions of the industrial region and also to make use of the mineral and energy resources. Recycling of these waste materials can be done by certain agglomerating process. In some cases briquetting is the best approach. Brex (briquettes) are prepared from stiff extrusion with iron bearing wastes. These brex has certain advantages over other agglomerates which makes them the efficient charge material for the blast furnace operation

Magnetic Fields in Multiphase Turbulence: Impacts on Dynamics and Structure

Both multiphase gas and magnetic fields are ubiquitous in astrophysics. However, the influence of magnetic fields on mixing of the different phases is still largely unexplored. In this study, we use both turbulent radiative mixing layer (TRML) and turbulent box simulations to examine the effects of magnetic fields on cold gas growth rates, survival, and the morphology of the multiphase gas. Our findings indicate that, in general, magnetic fields suppress mixing in TRMLs while turbulent box simulations show comparatively marginal differences in growth rates and survival of the cold gas. We reconcile these two seemingly contrasting results by demonstrating that similar turbulent properties result in comparable mixing -- regardless of the presence or absence of magnetic fields. We, furthermore, find the cold gas clump size distribution to be independent of the magnetic fields but the clumps are more filamentary in the MHD case. Synthetic MgII absorption lines support this picture being marginally different with and without magnetic fields; both cases aligning well with observations. We also examine the magnetic field strength and structure in turbulent boxes. We generally observe a higher mean magnetic field in the cold gas phase due to flux freezing and reveal fractal-like magnetic field lines in a turbulent environment.Comment: 23 pages, 18 figures (+5 in appendices). The visualisations related to this study can be found at http://hiteshkishoredas.github.io/research/mhd_multiphase.htm

A Study On Applications And Techniques Of Surface Re- Construction

This paper describes a general method for automatic reconstruction of accurate, concise, piecewise smooth surfaces from unorganized 3D points. Instances of surface reconstruction arise in numerous scientific and engineering applications, including reverseengineering, the automatic generation of CAD models from physical objects etc. Previous surface reconstruction methods have typically required additional knowledge, such as structure in the data, known surface genus, or orientation information. In contrast, the method outlined in this paper requires only the 3D coordinates of the data points. From the data, the method is able to automatically infer the topological type of the surface, its geometry, and the presence and location of features such as boundaries, creases, and corners. The surface reconstruction method has three major phases: Initial surface estimation, Mesh optimization, and piecewise smooth surface optimization. In this paper emphasis has been given on the initial surface estimation

Prolonged Survival of the Patient with Head and Neck Cancer with Squamous Cell Carcinoma treated with Cetuximab: A Case Report

Introduction: Cetuximab, an epidermal growth factor (EGFR) inhibitor has radio sensitizing activity for locoregionally, advanced head and neck cancer (LAHNC). The drug is either used in combination with radiotherapy or in combination with other chemotherapeutic drugs.Case Presentation: A 35-year-old male patient diagnosed with cancer of tongue atloco regional stage who had previously undergone hemiglossectomy was treated with TPF (docetaxel, cisplatin and 5-fluorouracil) as induction therapy(ICT)followed by concurrent local radiation therapy (RT) and cetuximab for 6weeks.The first recurrence appeared 4 years after the surgery, which was treated with RT along with standard treatment with cetuximab for 6weeks.Second recurrence was treated with cetuximab in combination with cisplatin and docetaxel. The patient survived for 8 years since he began his treatment.Conclusion: Cetuximab in combination with RT and other chemotherapeutic drugs can offer a longer survival in patients with both recurrent, locally advanced and metastatic squamous cell carcinoma of head and neck cancer

Oral premedication for pediatric anaesthesia: a comparison between midazolam and clonidine

Background:In children any anticipated surgery is associated with profound psychological stress to the patients. To allay this stress and anxiety, wide variety of pharmacological interventions are used.Methods: A prospective observational study was carried out between July’2005 and June’2006 in a tertiary care hospital in Assam. The study included children undergoing surgery under general anaesthesia in age group 2-10 years. Sixty children were divided into two groups, in one group patients received oral midazolam and other group received oral clonidine as pre-medicant.Results: In the midazolam group 23 (76.67%) children had no apprehension after parental separation and at induction (P˂0.001), sedation score at induction was significant higher in midazolam group versus clonidine group (93.33% versus 66.6%, P<0.01), clonidine resulted in a more stable pulse and blood pressure peri-operatively (P<0.05).Conclusion: Oral midazolam has better efficacy in terms of preoperative sedation and oral clonidine had stable hemodynamic profile and better analgesia in the clonidine group

Designing a Forward Convertor with Transformer Reset and Synchronous Rectification

The use of an active clamp circuit over the famous RCD clamp is due to its superiority for its better efficiency, more duty cycle, lower current stress and no energy dissipation as the magnetising current is recycled and used again. The use of the transformer instead of the normal buck converter is because by using a transformer the voltage can be stepped down to quite a low value, i.e. more than 2 times less of the input voltage which was not possible in the buck converter. The use of synchronous rectification is to increase the efficiency of the system, as the body diode conduction losses are quite low for a Mosfet and thus less heat produced in using that. The circuit for a forward converter with an active clamp and transformer reset is made with the synchronous rectificatio