Chemical actinometry (IUPAC Technical Report)

2004 ◽  
Vol 76 (12) ◽  
pp. 2105-2146 ◽  
Author(s):  
H. J. Kuhn ◽  
S. E. Braslavsky ◽  
R. Schmidt
Keyword(s):  
Electronic Devices ◽  
Absolute Measurement ◽  
Chemical Reactor ◽  
Chemical System ◽  
Photon Flux ◽  
Advantages And Disadvantages ◽  
Liquid Phases ◽  
Standard Procedures ◽  
Technical Report ◽  
Incident Photon Flux

This document updates the first version of the IUPAC technical report on “Chemical actinometers” published in Pure Appl. Chem. 61 ,187-210 (1989). Since then, some methods have been improved, procedures have been modified, and new substances have been proposed as chemical actinometers. An actinometer is a chemical system or a physical device by which the number of photons in a beam absorbed into the defined space of a chemical reactor can be determined integrally or per time. This compilation includes chemical actinometers for the gas, solid, microheterogeneous, and liquid phases, as well as for the use with pulsed lasers for the measurement of transient absorbances, including the quantum yield of phototransformation, as well as the literature for each of the actinometers. The actinometers listed are for the use in the wavelength range from the UV to the red region of the spectrum. A set of recommended standard procedures is also given. Advantages and disadvantages are discussed regarding the use of chemical actinometers vs. electronic devices for the measurement of the number of photons absorbed. Procedures for the absolute measurement of incident photon flux by means of photodiodes are also discussed.

scholarly journals Analysis of methods for measuring the dielectric properties of materials in the microwave range of wavelengths.

2021 ◽  
Author(s):  
D.G. Fomin ◽  
◽  
N.V. Dudarev ◽  
S.N. Darovskikh ◽  
◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Communication Systems ◽  
Electronic Devices ◽  
Microwave Range ◽  
Advantages And Disadvantages ◽  
Microwave Electronic ◽  
Functional Features ◽  
Properties Of Materials ◽  
Materials Used ◽  
Resonant Method

One of the modern trends in the development of communication systems, information and telecommunication systems, air traffic control systems, etc. is the transition and development of higher-frequency wavelength ranges. In this regard more and more stringent requirements (in terms of spectrum, out-of-band and spurious radio emission, and in the shape of the output signal) are imposed on radio engineering devices that transmit and receive microwave radio signals. As a result, the requirements for the design and functional features of microwave electronic devices are increasing. One of these requirements is to assess the degree of compliance with the required values of dielectric properties of materials used in the design of microwave electronic devices. This requirement is justified by the fact that the electrical parameters of such microwave devices as: strip filters, power dividers, printed antennas and others, directly depend on the dielectric properties of the materials used in their substrate designs. In this regard, three main methods have now emerged for assessing the dielectric properties of materials: the resonant method, the non-resonant method, and the free space method. Aim. The aim of this article is to carry out a comparative analysis of the known methods for measuring the dielectric properties of materials in the microwave range of wavelengths and devices for their implementation. Materials and methods. The authors of the article reviewed the scientific literature of domestic and foreign publications. Results. For each of the methods for measuring the dielectric properties of materials, their main idea, practical implementation, a mathematical model for processing experimental data and areas of application are given. The advantages and disadvantages for each of the methods for measuring the dielectric properties of materials are given too. Conclusion. The applicability of each of the considered methods depends on such factors as: the shape of the investigated dielectric material, its state of aggregation, the possibility of measuring amplitude or complex transmission and reflection coefficients, the presence of an anechoic chamber, etc.

The Research of PWM Controlling Capacitance SVC Based on RB-IGBT

2010 ◽  
Vol 44-47 ◽  
pp. 3970-3975
Author(s):  
Ke Wang ◽  
Bin Chen ◽  
Wen Han Chen ◽  
Hua Xu ◽  
Jia Xin Yuan
Keyword(s):  
Reactive Power ◽  
Electronic Devices ◽  
Reactive Power Compensation ◽  
Power Electronic ◽  
Practical Application ◽  
Advantages And Disadvantages ◽  
Compensation Principle ◽  
New Type

At first, this paper compared the present some advantages and disadvantages of reactive power compensation devices, and analysis the disadvantages of these devices in practical application deficiencies, then put forward a new kind of reactive power compensation principle. With the development of power electronic devices, this paper put forward a new type of reactive power compensation which based on RB-IGBT of SVC mode, synthesize the advantages of domestic reactive power compensation devices at present, and the prospect of application is very good.

Wearable sensing devices for upper limbs: A systematic review

2020 ◽  
Vol 235 (1) ◽  
pp. 117-130
Author(s):  
Mingjie Dong ◽  
Bin Fang ◽  
Jianfeng Li ◽  
Fuchun Sun ◽  
Huaping Liu
Keyword(s):  
Upper Limb ◽  
State Of The Art ◽  
Electronic Devices ◽  
The Body ◽  
Future Research ◽  
Upper Limbs ◽  
Advantages And Disadvantages ◽  
Wearable Sensing ◽  
Fast Development ◽  
Manufacturing Technologies

Wearable sensing devices, which are smart electronic devices that can be worn on the body as implants or accessories, have attracted much research interest in recent years. They are rapidly advancing in terms of technology, functionality, size, and real-time applications along with the fast development of manufacturing technologies and sensor technologies. By covering some of the most important technologies and algorithms of wearable devices, this paper is intended to provide an overview of upper-limb wearable device research and to explore future research trends. The review of the state-of-the-art of upper-limb wearable technologies involving wearable design, sensor technologies, wearable computing algorithms and wearable applications is presented along with a summary of their advantages and disadvantages. Toward the end of this paper, we highlight areas of future research potential. It is our goal that this review will guide future researchers to develop better wearable sensing devices for upper limbs.

scholarly journals Temperature-entropy diagrams for calculating cycles of refrigerating machines using refrigerant mixtures

2020 ◽  
Vol 2020 (4) ◽  
pp. 79-86
Author(s):  
Vladimir Grigorievich Bukin ◽  
Alexey Vasilievich Ezhov ◽  
Aleksander Ivanovich Andreev
Keyword(s):  
Energy Characteristics ◽  
Advantages And Disadvantages ◽  
Boiling Points ◽  
Refrigerant Mixtures ◽  
Liquid Phases ◽  
First Case ◽  
Pure Substances ◽  
Temperature Levels ◽  
Internal Irreversibility ◽  
Working Bodies

The article represents the advantages and disadvantages of refrigeration machines operating on non-azeotropic refrigerant mixtures. There has been illustrated their specific feature in comparison with pure substances: they are non-isothermal during phase transitions. It can be effective when cooling or heating flows that significantly change the temperature, and ineffective when working with volumes, where it is necessary to maintain a constant temperature. In the first case there takes place a decrease in the internal irreversibility of heat transfer processes in evaporators and condensers; in the second case - an increase. When using mixed refrigerants, it is possible to simultaneously obtain several temperature levels in a single-stage machine at the same pressure in the evaporators, they can obtain low boiling points of the refrigerant without vacuum in the evaporator and regulate the refrigeration capacity of the machine by changing the composition of the mixture. The prospects of using mixtures of working bodies of refrigerating machines have been proved. The diagrams T-S, T-ξ, i-ξ are presented allowing to calculate the cycle of the machine, to determine its operating parameters and to calculate the technical and energy characteristics. The developed thermal diagrams make it possible to accurately examine the dynamics of the boiling and condensation processes of a binary mixture, show the change in the concentration of the mixture in the vapor and liquid phases and make it possible to construct and calculate the cycle of a refrigeration machine operating on a mixed refrigerant. Examples of constructing cycles of two schemes of refrigeration machines operating on a mixed refrigerant are considered: with separation of the working substance flow and without separation. Methods for calculating the cycle are provided

scholarly journals WEB-BASED SCHEDULING APPLICATION AND MOTION SENSOR USING ARDUINO MEGA

2021 ◽  
Vol 4 (1) ◽  
pp. 28-32
Author(s):  
Januardi Nasir ◽  
Keyword(s):  
Time Delay ◽  
Web Application ◽  
Web Applications ◽  
Electronic Devices ◽  
Motion Sensor ◽  
Motion Sensors ◽  
Web Based ◽  
Advantages And Disadvantages ◽  
Internet Connection ◽  
Human Object

The purpose of this research is to find out how to make a web application that can control electronic devices in the building, find out how to make motion sensor circuits with Arduino Mega, electronic devices can be on or off, and find out which one is more efficient in using web applications and sensors. motion on the building. The results of this study indicate that the creation of a web scheduling application that can control the needs of building electronic equipment: webserver (hosting), internet connection, Ethernet shield, Arduino mega, relay module, and the use of motion sensors with Arduino Mega. which can adjust the sensitivity and time delay of signaling when there is the movement of a human object. The use of Ethernet shield and motion sensor each has advantages and disadvantages. It would be better if the two components were combined.

scholarly journals Behavioral health risks for students during distance education

2020 ◽  
Vol 99 (8) ◽  
pp. 854-860 ◽  
Author(s):  
Valery I. Popov ◽  
Olga Yu. Milushkina ◽  
Natalya A. Skoblina ◽  
Svetlana V. Markelova ◽  
Natalya V. Sokolova ◽  
...  
Keyword(s):  
Higher Education ◽  
Distance Learning ◽  
Negative Impact ◽  
Electronic Devices ◽  
Learning Technologies ◽  
Educational Process ◽  
Advantages And Disadvantages ◽  
Modern Development ◽  
Distant Education ◽  
Distance Learning Technologies

Introduction. The modern development of information and communication technologiesand the current epidemiological situation have led to the widespread use of distance educational technologies. The article presents the results of a statistical analysis of the data obtained during the hygienic assessment of the characteristics of the lifestyle and activity of students in the period of active introduction of forms and methods of distance education.Material and methods. An online survey of 498 students in 2019 during the period of traditional education and 1587 students in April 2020 during the implementation of the educational process in the distance format was conducted. The coordinator of the work was the Department of Hygiene of the Pediatric Faculty of the N.I. Pirogov Russian National Research Medical University, Moscow.Results. The obtained data allows talking about the negative impact of electronic devices on the lifestyle of students. A significant increase in the time of the use of gadgets (almost twice) and their number (2-4) when transferring the educational process to a remote format is proved. In general, the use of stationary and mobile electronic devices in more than 50% of respondents amounted to five hours or more. A decrease in the quality characteristics of the lifestyle of students in higher education during the transition to distant education has been established, while more than a third of them do not realize this. As risk factors, a decrease in motor activity, visual impairment, neuropsychic stress, poor nutrition, etc. In the absence of direct contact with university teachers, the opportunities for creating healthy lifestyle skills within the university are reduced and the importance of teachers as an authoritarian influence and a personal example for students is reduced.Conclusion. Informatization and the introduction of distance learning technologies in the higher education system require comprehensive studies of the advantages and disadvantages of such a learning format. The forced mass introduction of distance learning technologies in the educational process has exposed many problems that have not yet been given sufficient attention and, in the future, they can become the basis for promising research in the field of educational hygiene. The results obtained suggest that modern students do not pay enough attention to their lifestyle in the period of the distant education.

scholarly journals Use of piezoelement in ultrasound generation

2021 ◽  
Vol 289 ◽  
pp. 07027
Author(s):  
Shakhnoza Sultanova ◽  
Jasur Safarov ◽  
Azamat Usenov ◽  
Kamola Samatova
Keyword(s):  
Electronic Devices ◽  
Piezoelectric Element ◽  
Frequency Characteristics ◽  
Piezoelectric Transducers ◽  
Electrical Model ◽  
Advantages And Disadvantages ◽  
Piezoelectric Elements ◽  
Electromechanical Transducers

At present, ultrasonic (piezoelectric) transducers are the most promising electromechanical transducers for use in miniature electronic devices. However, the calculation of the piezoelectric element for an ultrasonic environment poses certain problems due to the large number of problems to be solved and its nonlinearity. The article describes the principles of operation of the piezoelectric element, analyzes their advantages and disadvantages, gives the characteristics of the piezoelectric elements, as well as proposes an algorithm for calculating the frequency characteristics of the piezoelectric element based on the electrical model of the piezoelectric element.

scholarly journals Mak Nyahs and Sex Reassignment Surgery – A Qualitative Study from Pahang, Malaysia

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Draman S ◽  
Maliya S ◽  
Syaffiq M ◽  
Hamizah Z ◽  
Abdul Hakim A ◽  
...  
Keyword(s):  
Adult Life ◽  
Primary Data ◽  
Sex Reassignment Surgery ◽  
Sex Reassignment ◽  
Snowball Sampling ◽  
Stable Relationship ◽  
Advantages And Disadvantages ◽  
Standard Procedures ◽  
Standardized Treatment ◽  
Sexual Reassignment Surgery

Introduction: Mak nyahs are locally known male-to-female transgenders in Malaysia. In Western countries, medicalization of transgenderism allows strictly selected patients to undergo sex reassignment surgery. However, a standardized treatment system is not yet available in Malaysia. A number of mak nyahs underwent sex reassignment surgery at their own will. This study aimed to explore mak nyahs’ knowledge and perception on sex reassignment surgery. Materials and Methods: A qualitative research was carried out from 13th July 2016 till 31st August 2016 among 8 adult mak nyahs in Kuantan, Pahang. Snowball sampling was used. Participants who gave verbal consent were interviewed individually and in focus groups. Data obtained was transcribed and used as the primary data source. Results: All informants were Malays and Muslims. They generally had some knowledge about the standard procedures and risks in sex reassignment surgery. All informants expressed their desire to have the surgery, but chose not to. Reasons discouraging them from having the surgery were: i) religion, ii) forbiddance from family, iii) fear of regret, iv) death from surgery, and v) the lack of necessity. Factors driving them to have the surgery: i) more income from sex work, ii) pressure from sex clients, iii) securing a stable relationship, iv) self-satisfaction, and v) hope for a better future. Conclusion: Religion seemed to be the main reason refraining them from undertaking the surgery. Counselling mak nyahs should include the advantages and disadvantages of sexual reassignment surgery. Islamic religious preaching is very important to help reduce high risk behaviours, as well as teaching mak nyahs to cope with challenges in adult life. Further research is necessary to show association between religious knowledge and successful rehabilitation of the mak nyahs’ community.

scholarly journals Métodos de medición de espesores de películas delgadas basadas en óxidos semiconductores

2018 ◽  
Vol 64 (4) ◽  
pp. 364
Author(s):  
Leandro A. Ramajo ◽  
Edgar Villegas ◽  
Rodrigo Parra
Keyword(s):  
Solar Cells ◽  
Film Thickness ◽  
Spray Pyrolysis ◽  
Electronic Devices ◽  
Direct Methods ◽  
Indirect Methods ◽  
Transparent Films ◽  
Glass Substrates ◽  
Advantages And Disadvantages ◽  
Conductive Films

Transparent films based on Ti, Sn and Zn oxides are of great importance in electronic devices such as sensors, solar cells and conductive films, then the characterization techniques are highly relevant. The aim of this work is to identify the advantages and disadvantages of direct methods, such as profilometry, and indirect methods such as ellipsometry and spectrophotometry used to quantify film thickness. In this work, films were deposited by spray-pyrolysis on glass substrates at 425±C. Thicknesses varied between 150 and 300 nm. Thicknesses calculated by means of spectrophotometry and ellipsometry, led to differences below 10% and 20 %, respectively, with respect to the value measuredby profilometry.

scholarly journals Permeation-enhancing properties of Nepeta cataria var. citriodora dry extract

2013 ◽  
Vol 59 (3) ◽  
pp. 5-16 ◽  
Author(s):  
Andrzej M. Winnicki ◽  
Jakub M. Śmieszek ◽  
Danuta Partyka ◽  
Daniel Modnicki
Keyword(s):  
Ursolic Acid ◽  
Log P ◽  
Dry Extract ◽  
Nepeta Cataria ◽  
Liquid Phases ◽  
Standard Procedures ◽  
Model Substance ◽  
Solvent Systems ◽  
Permeation Test

Abstract This paper presents the research on permeation enhancing properties of Nepeta cataria var. citriodora (catnip) dry extract in comparison to oleanolic acid and ursolic acid. Progesterone was chosen as a model substance for permeation test. The hydrogels made of hydroxypropylmethylcellulose with progesterone, enhancers and ethanol were applied in the study. The in vitro progesterone penetration test was based on the method proposed by Fürst, using artificial lipophilic membranes which were made of colloxylin and dodecanol. Statistical analyses showed an increase in penetration of progesterone caused by catnip dry extract in comparison to ursolic acid and blank sample. HPLC assay was applied to study the effect of enhancers on progesterone physicochemical properties. The solubility of progesterone was tested in solvent systems corresponding to liquid phases of gels. The statistical increase in progesterone solubility was observed in the presence of dry extract in comparison to the result from ursolic acid-containing sample. The partition coefficient of progesterone was evaluated by standard procedures. The statistically significant reduction of log P values for progesterone was determined in the presence of catnip dry extract

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