Microwave

Microwave assisted radical organic syntheses

by Roy McBurney

Applications of microwave (MW)-assistance to radical-mediated organic preparations and procedures are reviewed.... more Applications of microwave (MW)-assistance to radical-mediated organic preparations and procedures are reviewed. Radical additions and cyclisations onto a wide range of acceptors benefited from the technique, as did organic halide reductions by tin hydrides and numerous cascade and sequential processes. Reaction times of chain processes initiated by AIBN were, in several cases, reduced to a few minutes. Regioselectivity in radical additions and ring closures was normally maintained under MW conditions, although stereoselectivities were usually poorer. MW methods have been developed for generation of C-, N-, O-, S- and P-centred radicals. As a result of this a notable number and diversity of heterocycles have been accessed. MW-methods have opened up several new and innocuous alternatives to toxic organotin reagents. Alkoxyamines smoothly release C-centred radicals and oxime ethers provide a variety of iminyl radicals on MW heating. In addition, several types of organo-element and organometallic precursors have yielded novel C-centred and hetero-radicals. To date applications of MW-assistance to homolytic processes are comparatively limited, but it is clear the alliance of the two holds a lot of promise.

Using the Microwaves to create ICISS as Method for Completely Extracting the Terrestrial Snail’s Flesh out of Shell (Cornu aspersum and Helix pomatia) while Inhibiting Animal’s Nervous System to Reduce Pain

by Adrian Toader-Williams

snail slaughter, hepatopancreas, cochilie, sacrificare, microunde, meat bone separation, intimate contact induced surface separation, animal protection, animal rights, natural rights, natural economy,

A novel method it was conceived as to quickly inhibit snails’ nervous system in order to reduce pain and suffering and... more A novel method it was conceived as to quickly inhibit snails’ nervous system in order to reduce pain and suffering and to facilitate the complete meat removal from the shell, Fig.1. The snails have been introduced into a microwave oven Vortex R, model WD800L20-8, capable to generate 800W of microwave power at 2450 MHz frequency. Using the oven set on medium by trial and error the optimum times for snails’ slaughter was found, Fig.2.  The snails’ nervous system is being inhibited within the first 2-3 seconds of exposure to microwave, as they did not respond to tactile touches using sharp needles. The nervous system is being affected by the change in temperature as well by the non-thermal effects,, also states in their work Orendacova et all, (2007). },

Regioselective one pot synthesis of 2-alkyl/aryl-4h-benzo[1,4]thiazine-3-one via microwave irradiation

by Omair Khan

Sukanta Kamila, Benjamin Koh, Omair Khan, Hongming Zhang, Edward R. Biehl. Regioselective one pot synthesis of 2-alkyl/aryl-4h-benzo[1,4]thiazine-3-one via microwave irradiation. Journal of Heterocyclic Chemistry, 43(6):16411646, 2006. doi:10.1002/jhet.5570430632

A series of 2-alkyl/aryl-4H-benzo[1,4]thiazine-3-ones have been synthesized by microwave irradiation of... more A series of 2-alkyl/aryl-4H-benzo[1,4]thiazine-3-ones have been synthesized by microwave irradiation of ethyl-2-bromo-2-alkyl/aryl acetate and 2-amino thiophenol in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene and N-methylpiperidine. All compounds were characterized by 1H NMR, 13C NMR and elemental analyses, and by X-ray crystallography in the case of 2-methyl-4H-benzo[1,4]thiazin-3-one.

Finite Element Modeling for Microwave Tomography

by Elia Attardo

Co-authored with A. Borsic, P.M. Meaney, G. Vecchi, IEEE APS/URSI Spokane, Washington, USA, July 2011

This paper presents a Finite Element Modelling for Microwave Imaging tomography based on edge basis functions. In... more This paper presents a Finite Element Modelling for Microwave Imaging tomography based on edge basis functions. In particular a new technique is used to compute the antenna parameters. This novel procedure will provide a general method to enforce the excitation as a specific modal distribution, and to extract the voltage from the employed antenna. We show the model for the Microwave Imaging system including the antennas and we report a comparison between measured and simulated data.

Microwave-induced molecular rearrangements. Flash thermolysis in the gas-phase and in solution: Synthesis of quinolones and naphthyridones

by Ben Chalmers

Computer Modelling of the Energy Distribution within Wood throughout Microwave Processing. Computers, Materials & Continua, 8:3.

by Dr. Mihai Daian

Daian, M., Taube, A., Torgovnikov, G., Daian, G., Shramkov, Y., 2009,

Daian M., 2006, Design, Modelling and Testing of the Microwave Wood Softening Applicators: Wood Bending Applications. Confidential report for CRC Wood Innovations.

by Dr. Mihai Daian

The Development and Evaluation of New Microwave Equipment and Its Suitability for Wood Modification

by Dr. Mihai Daian

Dielectric-loaded free-electron maser in stripline structure

by Moshe Einat

Nuclear Instrum. and Methods, Vol. A375, pp. 21-25 (1996)

A New, High–performance, Heterodyne Spectrometer for Ground–based Remote Sensing of Mesospheric Water Vapour

by Kristofer Hallgren

ARIS-Campaign: Intercomparison of three 22GHz radiometers for middle atmospheric water vapor at the Zugspitze in winter 2009

by Kristofer Hallgren

Secador de arcilla industrial continuo a presión atmosférica con microondas

by John Jairo Pantoja Acosta

Co-authored with Oliver Silva Barrera and Fernando Herrera. Published in Premio Corona Pro Hábitat, pp 36-37, 2009.

Dielectric properties of Zea mays kernels–studies for microwave power processing applications

by Vasile Surducan

Microwave assisted thin-layer chromatography—an improved separation technique

by Vasile Surducan

Microwave-Assisted Phenothiazines Preparation by Thionation of Diphenylamines

by Vasile Surducan

Medical and Scientific Apparatus with Thermal and Nonthermal Effect

by Vasile Surducan

Microwave radiation is widely used in medical and scientific applications. Despite its huge occurrence, the microwave... more Microwave radiation is widely used in medical and scientific applications. Despite its huge occurrence, the microwave effect (on the assumption of interaction between the microwave incident power and the probe or biomass) is not entirely known. The most known effect of the microwave radiation is heating (the thermal effect). However, due the mechanism of interaction between microwave radiation and bio-molecule, the microwave power deposition into the tissue is based on a selective absorption. During a microwave treatment, into the tissue may occur dipolar displacement, free charge current or/and resonant absorption. What makes difference in generating a thermal or non-thermal effect is the microwave incident energy, the local characteristics of the biomass and the way in which the human body is adapting and reacting to the microwave stimulus. This article briefly presents the authors experience in understanding the microwave interaction and use the microwave radiation in designing scientific and medical equipments.

Variable Power, Short Microwave Pulses using a CW Magnetron

by Vasile Surducan

Fine control of microwave power radiation in medical and scientific applications is a challenging task. Since a... more Fine control of microwave power radiation in medical and scientific applications is a challenging task. Since a commercial Continuous Wave (CW) magnetron is the most inexpensive microwave device  available today on the market, it becomes the best candidate for a microwave power generator used in medical diathermy and hyperthermia treatments or high efficiency chemical reactions using microwave reactors as well. This article presents a new method for driving a CW magnetron with short pulses, using a modified commercial Zero Voltage Switching (ZVS)  inverter, software driven by a custom embedded system. The microwave power generator designed with this method can be programmed for output microwave pulses down to 1% of the magnetron’s power and allows microwave low frequency pulse modulation in the range of human brain electrical activity, intended for medical applications. Microwave output power continuous control is also possible with the magnetron running in the oscillating area, using a dual frequency  Pulse Width Modulation (PWM), where the low frequency PWM pulse is modulating a higher resonant frequency required by the ZVS inverter’s transformer. The method presented allows a continuous control of both power and energy (duty-cycle) at the inverter’s output.

Determination of Microwave Generators’ Performance for Medical Applications

by Vasile Surducan

Microwave (MW) radiation (300MHz-30GHz) is a non-ionizing radiation  widely used in medical and scientific... more Microwave (MW) radiation (300MHz-30GHz) is a non-ionizing radiation  widely used in medical and scientific applications, mostly for stimulation treatments. The most known effect of the high power MW radiation is heating (known also as the thermal effect) used in diathermy and hyperthermia medical treatments. Due to the mechanism of interaction between the MW radiation and biomolecules, the MW power deposition into the tissue is based on a selective absorption. During a MW treatment, into the tissue may occur dipolar displacement, free charge current or/and resonant absorption, all of which highly depend on the MW radiation parameters. We present here a simple and effective method which determines the absorbed MW power into a probe simulating the human body tissue, offering useful information about the MW generator’s performance.  In this method we are using our custom designed MW power generators, having specific automation, based on continuous wave (CW) magnetron.

Embedded system controlling microwave generators in hyperthermia and diathermy medical devices

by Vasile Surducan

Microwave Hyperthermia (MH) is a medical procedure of rising the human body tissue temperature between 41.5C and 45C... more Microwave Hyperthermia (MH) is a medical procedure of rising the human body tissue temperature between 41.5C and 45C using electromagnetic radiation and maintaining the desired temperature during the treatment period. In this paper we present a part of our embedded system that can drive a continuous wave (CW) 2450 MHz magnetron as well as a 915 MHz RF power generator for pulse-modulated waves operating mode, measuring and managing the patient's skin temperature feedback. This embedded system is intended for use in microwave hyper-thermia or microwave diathermy devices, with non-invasive regional or interstitial applicators. Our paper is structured in four chapters. The “Introduction” is briefly presenting the microwave hyperthermia essentials: microwave propagation, penetration depth, SAR and microwave heating mechanism. The “Design configuration” part presents the structure of our hyperthermia device with basic microwave generators and auxiliary equipment used for thermal management. The “Embedded design” chapter presents, in two subsections entitled “Hardware” and “Software”, the principles used for controlling the microwave generators together with the implemented solution and the essential aspects of our firmware as program flow. In “Conclusions”, preliminary results are analyzed in agreement with the IEC60601 standards and with the requested directions for further developments.

Near-field Effect of the Microwaves Power Applicators Investigated for Liquid Processing Applications

by Vasile Surducan

Microwave heating of high loss liquids was performed using two applicator types, a coaxial configuration and a pair of... more Microwave heating of high loss liquids was performed using two applicator types, a coaxial configuration and a pair of rectangular slot antennas. The temperature profiles in the as-heated liquid samples were investigated in real time. The dielectric properties of the samples were measured over a broad band of frequencies at the same temperature value as the highest one reached in the temperature profile. The heating depth in the liquid was compared to the dielectric loss for different samples. These investigations were performed for surface microwave processing in liquid mixtures (living tissues), for extraction applications and medical thermal treatments.