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Issue #3/2017
N.Murashova, A.Polyakova, E.Yurtov
Analysis of dynamics of scientific publications for areas related to nanotechnology and extraction
Analysis of dynamics of scientific publications for areas related to nanotechnology and extraction
Publication dynamics in the ScienceDirect database for the period from 1980 to 2015 was analyzed for the areas related to nanotechnology and extraction. The most dynamically developing directions of research were determined.
Теги: development trends of scientific fields extraction nanotechnology number of publications тенденции развития научных направлений число публикаций экстракция
The analysis of the dynamics of scientific publications in international databases can be a tool to assess the interest of the scientific community to specific fields and objects of research. The analysis of the dynamics of publications on a certain topic for long enough (at least during 15 years) period of time allows to assess the interest in this subject compared to other areas of research, the change of this interest in time, to predict the development of the research field. The analysis of the dynamics of scientific publications can serve as a complement to other methods for the evaluation of trends of development of scientific directions, including review articles in national and international scientific journals [1, 2] and the evaluation of results of scientific conferences [3].
The aim of this paper is the analysis of the dynamics of scientific publications in international database in the fields related to nanotechnology and extraction. It is known that nanoscale particles and nanostructures can spontaneously arise in the extraction systems and influence the characteristics of the process, and some special obtained nanostructures can be used for extraction and separation of substances [4, 5].
To assess the dynamics of publications, we have used the capabilities of the ScienceDirect database, an information platform of Elsevier, which contains 25% of world scientific publications. ScienceDirect provides coverage of publications from all areas of science, provides access to over 13 million publications from 2500 journals and more than 33,000 books of Elsevier, and to the journals published by other scientific communities [6].
We analyzed the number of publications between 1980 and 2015, where the key concepts are included in the title and keywords or in the title, keywords and abstract, which allowed to cut off most random hits and to adequately assess the level of interest of scientists to this field. The number of publications and its rate of growth were compared with other scientific areas.
To identify trends in the development of specialized fields of study or in change of interest in the objects of study, it is advisable to search for publications on two or more key concepts, which can be included in the title, keywords and abstract. To reduce the effect of random fluctuations in the number of publications by year and better identify the trend, it is expedient to use data on the number of publications for five years.
RESULTS AND DISCUSSION
To assess trends in the development of major areas of science and technology, we have compared the number of publications on the widely used methods of separating substances in chemical engineering (filtration, sorption, leaching, liquid extraction) and nanotechnology and nanomaterials (words with the prefix "nano"). We have analyzed the number of publications, where the key concepts were included into the title and keywords. Fig.1 shows data on the number of publications over a five-year period.
As can be seen from Fig.1, by the number of publications the traditional methods of chemical technology can be placed in descending order: filtration, sorption, leaching, liquid extraction. This order is not changed for the past 30 years. The rate of growth in the number of publications in these areas varies. The average time of doubling in the number of publications is 8.8 years for sorption, 9.1 years for leaching, 9.8 years for filtration, 11.6 years for liquid extraction.
Since the mid 1990-ies there has been a sharp increase in the number of studies in the field of nanotechnology and nanomaterials. The rate of this growth is significantly higher than for the traditional methods of chemical technology and the doubling time in the number of publications is 2.5 years. For the period from 2011 to 2015, the number of publications in the field of "nano" caught up with "sorption" and has closer to "filtration". Thus, the analysis of the dynamics of publications in ScienceDirect database confirmed well-known fact of sharp growth of interest in research in the field of nanomaterials and nanotechnology since the mid-1990-ies–beginning of 2000-ies. On the other hand, judging by the number of publications, the interest of scientists to nanotechnology and nanomaterials is comparable to the interest in such a long time developing field of chemical technologies, as sorption, and is less than the interest in filtration. Despite the lack of special support programs such as the National Nanotechnology Initiative in the United States, the interest of researchers to work in the traditional areas of chemical engineering related with separation of substances, is not reduced.
Additionally the dynamics of publications on terms "sorbent", "extractant" and "nanoparticle" (nanoparticle) was analyzed. The number of publications where the key concepts are included in the title and keywords was analyzed.
The exponential growth in the number of publications was identified for research in the field of both traditional chemical technologies and nanotechnology. But the speed of growth in the number of publications where the title and keywords include the term "nanoparticle", is significantly higher than for the terms "sorbent" and "extractant". The doubling time in the number of publications is 7.1 years for the term "sorbent", 10.7 years for the "extractant" and 2.6 years for "nanoparticle", which is consistent with earlier data on the average doubling time for the words "sorption", "liquid extraction" and "nano".
Of interest is the dynamics of publications devoted to the study and use of nano-sized objects in the extraction systems i.e. related to both nanotechnology and extraction.
Among such publications it is possible to allocate three areas:
• use of liquid extraction for release and separation of nanoscale particles, such as fullerenes;
• use of nanoparticles and nanostructures to create new and improve the existing methods of extraction;
• problems of spontaneous formation of nanoscale objects, such as reverse micelles or nanoparticles of solid phase in extraction systems and their effects on the parameters of extraction.
The dynamics of publications on the use of liquid extraction for extraction and separation of fullerenes and their derivatives in comparison with the extraction and separation of some metals (copper, iron, cobalt, lanthanides, uranium and platinum) was studied. We analyzed the number of publications for each five years, where the key concept ("solvent extraction" plus the name of the substance) is included in the title, keywords and abstract (Fig.2).
It should be noted the increase in the number of publications devoted to liquid extraction of all mentioned metals in recent years. The leader is consistently the extraction of copper, in the second place is iron. In 1980-1990-ies the third place by the number of publications was occupied by liquid extraction of uranium, in the future, the interest has shifted to cobalt.
Since the early 1990-ies, when the first article were published, until the present time, extraction of fullerenes in the number of publications is noticeably inferior to extraction of metals. The number of publications on this topic is a few per year and not more than 20 in five years. It is possible to note the increasing number of publications about three times in the period 2011–2015, which indicates an increased interest in the extraction of fullerenes and their derivatives. Dominant methods of extraction of fullerenes are liquid extraction by toluene at an additional ultrasonic treatment, liquid extraction by toluene in the presence of salts and Soxhlet extraction [7].
Problems of the formation of nanoparticles and nanostructures in extraction systems and their application for extraction in some cases are related to each other. In the extraction systems in the bulk phase and near the phase boundary, the formation of a number of nanostructures including micelles, microemulsions, liquid crystals, nanoparticles of a solid phase and gel from them is possible. Structure formation in the extraction system affects the distribution ratio and separation factor of substances, the extraction rate and the phase separation rate. In some cases, the formation of nanostructures in the extraction systems is undesirable, since they reduce the extraction rate, worsen the phase separation, reduce the separation factors. In other cases, spontaneously formed nanostructures, such as reverse micelles or microemulsions can increase the distribution ratio of substances. This allows to use them in the traditional extraction processes or develop new ones [4, 5].
Nanoparticles (e.g., magnetic nanoparticles or carbon nanotubes) and nanostructures formed by surface-active substances (for example, reverse micelles or microemulsion) can be used for the extraction and separation of substances. Reverse micelles and microemulsions can be formed spontaneously in the extraction systems at the association of the surfactant molecules. When choosing publications, the following combinations of terms included in the title, keywords and abstract were considered: "solid-phase extraction + carbon nanotube"; "solid-phase extraction + magnetic nanoparticle"; "extraction + reverse micelle"; "extraction + microemulsion" (Fig.3).
The considered areas of research can be divided into two groups: with long-term slow growth ("extraction + reverse micelle"; "extraction + microemulsion"); with the explosive growth in the last 15 years ("solid phase extraction + carbon nanotube"; "solid-phase extraction + magnetic nanoparticle"). In the period from 1980 to 2010, there is a linear increase in the number of publications associated with the study and application in extraction systems of such well-known objects of colloid chemistry, as reverse micelles and microemulsions. In this area a progress has been achieved and there are examples of the practical application of the developed methods [8]. In the last five years, a linear increase in the number of publications related to the extraction and microemulsion, but a decrease in the number of publications related to the extraction and reverse micelles are observed. Micellar extraction (extraction by reverse micelles) is often used for extracting substances of biological origin. Recently, an another method of extraction of biologically active substances by supercritical fluid extraction is widespread. It is possible that the interest of researchers working in the field of extraction, separation and analysis of biologically active substances, has shifted from one extraction method to another.
Since 2001, the sharp increase in the number of publications on solid-phase extraction using new nanoscale objects, magnetic nanoparticles and carbon nanotubes, is noted. These methods are offered for release and concentration of organic and inorganic substances in analytical purposes. Magnetic nanoparticles of Fe3O4 with different types of surface modifications, magnetic nanoparticles, encapsulated inside carbon nanotubes (endohedral functionalization) or grafted to the nanotube surface (exohedral functionalization) are used, and the CNTs act as a sorbent (a solid extractant) [9, 10]. It is likely that in the next five years growth trend will continue. But the possibility of preparative applications of such methods remain questionable.
The results of the evaluation of the dynamics of publications devoted to the study and use of nano-sized objects in the extraction systems are confirmed by the analysis of the characteristics of the scientific journals that published the largest number of articles on the considered areas (table). Articles about study and application of reverse micelles and microemulsion in extraction systems are published in journals of fundamental, applied and technological fields. Articles related to the extraction, magnetic nanoparticles or carbon nanotubes are mostly published in journals devoted to analytical chemistry. The latter have on average higher impact factor than journals with articles related to the extraction and reverse micelles or microemulsions.
CONCLUSIONS
Thus, the analysis of the dynamThus, the analysis of the dynamics of scientific publications presented in international database ScienceDirect for the period 1980–2015 years in areas related to nanotechnology and liquid extraction, showed that since the mid 1990-ies there has been a sharp increase in research in field of nanotechnology and nanomaterials. Currently, this area is comparable by the number of publications to such well-known methods, as sorption and filtration.
Traditional methods of chemical technology can be placed by a number of publications in the following order (in descending): filtration, sorption, leaching, liquid extraction. The analysis of the number of publications devoted to the liquid extraction of certain metals allows to select two leaders: copper and iron. Extraction of fullerenes by this indicator is noticeably inferior to metal extraction, although in 2011–2015 years there has been an increase in the number of publications on this topic.
The aim of this paper is the analysis of the dynamics of scientific publications in international database in the fields related to nanotechnology and extraction. It is known that nanoscale particles and nanostructures can spontaneously arise in the extraction systems and influence the characteristics of the process, and some special obtained nanostructures can be used for extraction and separation of substances [4, 5].
To assess the dynamics of publications, we have used the capabilities of the ScienceDirect database, an information platform of Elsevier, which contains 25% of world scientific publications. ScienceDirect provides coverage of publications from all areas of science, provides access to over 13 million publications from 2500 journals and more than 33,000 books of Elsevier, and to the journals published by other scientific communities [6].
We analyzed the number of publications between 1980 and 2015, where the key concepts are included in the title and keywords or in the title, keywords and abstract, which allowed to cut off most random hits and to adequately assess the level of interest of scientists to this field. The number of publications and its rate of growth were compared with other scientific areas.
To identify trends in the development of specialized fields of study or in change of interest in the objects of study, it is advisable to search for publications on two or more key concepts, which can be included in the title, keywords and abstract. To reduce the effect of random fluctuations in the number of publications by year and better identify the trend, it is expedient to use data on the number of publications for five years.
RESULTS AND DISCUSSION
To assess trends in the development of major areas of science and technology, we have compared the number of publications on the widely used methods of separating substances in chemical engineering (filtration, sorption, leaching, liquid extraction) and nanotechnology and nanomaterials (words with the prefix "nano"). We have analyzed the number of publications, where the key concepts were included into the title and keywords. Fig.1 shows data on the number of publications over a five-year period.
As can be seen from Fig.1, by the number of publications the traditional methods of chemical technology can be placed in descending order: filtration, sorption, leaching, liquid extraction. This order is not changed for the past 30 years. The rate of growth in the number of publications in these areas varies. The average time of doubling in the number of publications is 8.8 years for sorption, 9.1 years for leaching, 9.8 years for filtration, 11.6 years for liquid extraction.
Since the mid 1990-ies there has been a sharp increase in the number of studies in the field of nanotechnology and nanomaterials. The rate of this growth is significantly higher than for the traditional methods of chemical technology and the doubling time in the number of publications is 2.5 years. For the period from 2011 to 2015, the number of publications in the field of "nano" caught up with "sorption" and has closer to "filtration". Thus, the analysis of the dynamics of publications in ScienceDirect database confirmed well-known fact of sharp growth of interest in research in the field of nanomaterials and nanotechnology since the mid-1990-ies–beginning of 2000-ies. On the other hand, judging by the number of publications, the interest of scientists to nanotechnology and nanomaterials is comparable to the interest in such a long time developing field of chemical technologies, as sorption, and is less than the interest in filtration. Despite the lack of special support programs such as the National Nanotechnology Initiative in the United States, the interest of researchers to work in the traditional areas of chemical engineering related with separation of substances, is not reduced.
Additionally the dynamics of publications on terms "sorbent", "extractant" and "nanoparticle" (nanoparticle) was analyzed. The number of publications where the key concepts are included in the title and keywords was analyzed.
The exponential growth in the number of publications was identified for research in the field of both traditional chemical technologies and nanotechnology. But the speed of growth in the number of publications where the title and keywords include the term "nanoparticle", is significantly higher than for the terms "sorbent" and "extractant". The doubling time in the number of publications is 7.1 years for the term "sorbent", 10.7 years for the "extractant" and 2.6 years for "nanoparticle", which is consistent with earlier data on the average doubling time for the words "sorption", "liquid extraction" and "nano".
Of interest is the dynamics of publications devoted to the study and use of nano-sized objects in the extraction systems i.e. related to both nanotechnology and extraction.
Among such publications it is possible to allocate three areas:
• use of liquid extraction for release and separation of nanoscale particles, such as fullerenes;
• use of nanoparticles and nanostructures to create new and improve the existing methods of extraction;
• problems of spontaneous formation of nanoscale objects, such as reverse micelles or nanoparticles of solid phase in extraction systems and their effects on the parameters of extraction.
The dynamics of publications on the use of liquid extraction for extraction and separation of fullerenes and their derivatives in comparison with the extraction and separation of some metals (copper, iron, cobalt, lanthanides, uranium and platinum) was studied. We analyzed the number of publications for each five years, where the key concept ("solvent extraction" plus the name of the substance) is included in the title, keywords and abstract (Fig.2).
It should be noted the increase in the number of publications devoted to liquid extraction of all mentioned metals in recent years. The leader is consistently the extraction of copper, in the second place is iron. In 1980-1990-ies the third place by the number of publications was occupied by liquid extraction of uranium, in the future, the interest has shifted to cobalt.
Since the early 1990-ies, when the first article were published, until the present time, extraction of fullerenes in the number of publications is noticeably inferior to extraction of metals. The number of publications on this topic is a few per year and not more than 20 in five years. It is possible to note the increasing number of publications about three times in the period 2011–2015, which indicates an increased interest in the extraction of fullerenes and their derivatives. Dominant methods of extraction of fullerenes are liquid extraction by toluene at an additional ultrasonic treatment, liquid extraction by toluene in the presence of salts and Soxhlet extraction [7].
Problems of the formation of nanoparticles and nanostructures in extraction systems and their application for extraction in some cases are related to each other. In the extraction systems in the bulk phase and near the phase boundary, the formation of a number of nanostructures including micelles, microemulsions, liquid crystals, nanoparticles of a solid phase and gel from them is possible. Structure formation in the extraction system affects the distribution ratio and separation factor of substances, the extraction rate and the phase separation rate. In some cases, the formation of nanostructures in the extraction systems is undesirable, since they reduce the extraction rate, worsen the phase separation, reduce the separation factors. In other cases, spontaneously formed nanostructures, such as reverse micelles or microemulsions can increase the distribution ratio of substances. This allows to use them in the traditional extraction processes or develop new ones [4, 5].
Nanoparticles (e.g., magnetic nanoparticles or carbon nanotubes) and nanostructures formed by surface-active substances (for example, reverse micelles or microemulsion) can be used for the extraction and separation of substances. Reverse micelles and microemulsions can be formed spontaneously in the extraction systems at the association of the surfactant molecules. When choosing publications, the following combinations of terms included in the title, keywords and abstract were considered: "solid-phase extraction + carbon nanotube"; "solid-phase extraction + magnetic nanoparticle"; "extraction + reverse micelle"; "extraction + microemulsion" (Fig.3).
The considered areas of research can be divided into two groups: with long-term slow growth ("extraction + reverse micelle"; "extraction + microemulsion"); with the explosive growth in the last 15 years ("solid phase extraction + carbon nanotube"; "solid-phase extraction + magnetic nanoparticle"). In the period from 1980 to 2010, there is a linear increase in the number of publications associated with the study and application in extraction systems of such well-known objects of colloid chemistry, as reverse micelles and microemulsions. In this area a progress has been achieved and there are examples of the practical application of the developed methods [8]. In the last five years, a linear increase in the number of publications related to the extraction and microemulsion, but a decrease in the number of publications related to the extraction and reverse micelles are observed. Micellar extraction (extraction by reverse micelles) is often used for extracting substances of biological origin. Recently, an another method of extraction of biologically active substances by supercritical fluid extraction is widespread. It is possible that the interest of researchers working in the field of extraction, separation and analysis of biologically active substances, has shifted from one extraction method to another.
Since 2001, the sharp increase in the number of publications on solid-phase extraction using new nanoscale objects, magnetic nanoparticles and carbon nanotubes, is noted. These methods are offered for release and concentration of organic and inorganic substances in analytical purposes. Magnetic nanoparticles of Fe3O4 with different types of surface modifications, magnetic nanoparticles, encapsulated inside carbon nanotubes (endohedral functionalization) or grafted to the nanotube surface (exohedral functionalization) are used, and the CNTs act as a sorbent (a solid extractant) [9, 10]. It is likely that in the next five years growth trend will continue. But the possibility of preparative applications of such methods remain questionable.
The results of the evaluation of the dynamics of publications devoted to the study and use of nano-sized objects in the extraction systems are confirmed by the analysis of the characteristics of the scientific journals that published the largest number of articles on the considered areas (table). Articles about study and application of reverse micelles and microemulsion in extraction systems are published in journals of fundamental, applied and technological fields. Articles related to the extraction, magnetic nanoparticles or carbon nanotubes are mostly published in journals devoted to analytical chemistry. The latter have on average higher impact factor than journals with articles related to the extraction and reverse micelles or microemulsions.
CONCLUSIONS
Thus, the analysis of the dynamThus, the analysis of the dynamics of scientific publications presented in international database ScienceDirect for the period 1980–2015 years in areas related to nanotechnology and liquid extraction, showed that since the mid 1990-ies there has been a sharp increase in research in field of nanotechnology and nanomaterials. Currently, this area is comparable by the number of publications to such well-known methods, as sorption and filtration.
Traditional methods of chemical technology can be placed by a number of publications in the following order (in descending): filtration, sorption, leaching, liquid extraction. The analysis of the number of publications devoted to the liquid extraction of certain metals allows to select two leaders: copper and iron. Extraction of fullerenes by this indicator is noticeably inferior to metal extraction, although in 2011–2015 years there has been an increase in the number of publications on this topic.
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