Considering this ranking, the next step was to classify the members by audiovisual genres as well as by the age of the users to which these channels were aimed. In addition, I attempted to relate all this to the Spanish sociocultural context and examined, from a more sociological point of view, the possible deviations in the age ranges that could exist in the consumers of these channels.

Finally, after drawing this map, I related it to the concept of polymediation, which I explain in the next section. The map helped me to open up the qualitative research to propose new avenues of investigation that can help other studies related to YouTubers channels, as well as to their protagonists and users themselves in order to improve any aspect of this type of audiovisual structure.

#### **Polymediation**

Polymediation, as established by Madianou and Miller, is "an emerging environment of communicative opportunities that functions as an 'integrated structure' within which each individual medium is defined in relational terms in the context of all other media" [27]. In this sense, YouTube and the channels created by YouTubers are clear examples of polymediation, at least as far as its most basic structure is concerned.

From this perspective, Calka posed a question about how the media, identity, and our performance are related to an iconic saturated ecosystem. His research framed polymediation as a "discursive point of articulation for exploring the processes and outcomes of media convergence and fragmentation". That is, polymediation is a transition from thinking about the media as something one only consumes as one more product to understanding it as a process of which one has adopted. I think it is interesting to analyze this type of adaptation in the audio-visual genres. Calka sees it as:

An opportunity for connection, invention, re-invention, and community, for bolstering and verifying aspects of our identity or playing with new possibilities for what one might become. The complex relationship among media, identity, and performance is necessarily in flux. As our technological landscape changes, so will our identities and relationship to media. [28] (pp. 27–28)

Calka distinguished different levels of polymediation, which can best be treated under five key aspects [28] (p. 15–26):

Other authors, such as Madinou and Miller, understand polymedia as a new theory that can be used to understand the consequences of using digital media in the context of interpersonal communication [28] (p. 170). They understand a polymedia environment as an increasing number of communications technologies across different platforms that are used simultaneously or to complement one another. User identities across online platforms may be broadly similar or may shift in emphasis, from professional to social identity and among media. So, "the poly-media environment requires an individual's identity to perform different functions in a digital networked world" [29] (p. 25). However, it can happen as a communicative environment of affordances, not as a technologies catalogue. Thus, the primary concern of polymedia is to avoid the technological limitations and move toward the social interactions field, focusing on the emotional and ethical consequences. The reason for this is that each medium, with its different communicative possibilities, is deeply linked to the ways in which interpersonal communication through technology are experienced and managed. Some of those ways enabled by polymedia are "ultimately about a new relationship between the social and the technological, rather than merely a shift in the technology itself" [27] (p. 170). Madianou and Miller's main argument was that polymedia is about "a new set of social relations of technology, rather than merely a technological development of increased convergence" (p. 171). To understand this, they distinguished three preconditions: (1) Access and availability, (2) affordability, and (3) media literacy (p. 171). Polymedia is not just the environment, but is also how users relate to and develop these affordances, and how their emotions and their relationships flow (p. 172). Madianou and Miller posited that this flow or negotiation "often becomes the message itself" (p. 173). This means that it is not only about multimedia or media ecology, but is also polymediation of how the entire environment of different media affects or mediates between the media and the users.

Baym deepened the understanding of polymediation, highlighting seven key parameters: Kinds of interactivity, temporal structure, social cues, storage, replicability, reach, and mobility. Baym employed these key concepts to consider different facets of human communication, including the degree to which media is viewed as more or less authentic compared with face-to-face interaction; the sense of community, identity, gender, veracity, and the self; and how such factors work in various forms of highly personal or impersonal contexts for communication and the creation and maintenance of relationships [30].

Madinou et al. summarized polymedia as a transformation in technology and how users interact with it. People, traditionally limited to a couple of forms of media for communication, now have access to different media. However, the importance is not the number, but the new affordances and ways of using that offer temporality, storage capacity, reproducibility, materiality, mobility, and reach [27] (p. 183). There is a sense of re-socialization in media democracy and literacy, as users choose a medium as a shared social act. This is related to theories about mediation [29,31] or mediatization [32–34], which reflects the mutual shaping of social processes and the media and how to encompass the changes caused by the media into every aspect of our lives.

The concept of mediatization has its origins in the notion of replication, "the spreading of media forms to spaces of contemporary life that are required to be represented through media forms" [32] (p. 5). Both concepts come from the same theoretical background, but differ in application. Mediatization denotes the processes through which core elements of cultural or social activities assume media form. Therefore, those activities are relatively performed "through interaction with a medium, and the symbolic content and the structure of the social and cultural activities are influenced by media environments which they gradually become more dependent upon" [35] (p. 105). Mediatization highlights the independence of the media "with a logic of its own that other social institutions have to accommodate to". Simultaneously, these media "become an integrated part of other institutions" (id.). Mediatization also describes the transformation of many disparate social and cultural processes into forms or formats suitable for media representation [32] (p. 7). This (poly)mediatization is perhaps contradictory to the theories of globalization that hypothesize a flat world [36], as this cannot be alien to the peculiarities of each society. First, being a phenomenon that is already hugely popular, mediatization is far from reaching a significant level among the total potential users, at least in Spain. To discuss this unlikely globalization serves as an example in the cases of the Spanish Youtubers that I have chosen. I then wanted to examine how polymediation manifests itself in the Spanish case. For this, I analyzed the 10 most influential YouTubers using metrics from both YouTube and the qualitative data from SocialBlade.

#### **3. Results**

In 2016, I had the opportunity to visit Colombia to shoot a documentary in a mountainous area. In general, the landscapes and the people impacted me, but my most memorable moment was when, in a village with just one street, I met an eight-year-old boy interacting with his mobile phone. I was blown away by the discovery that he was a follower of elRubius, the popular Spanish Youtuber (Figure 1).

**Figure 1.** Colombian child using elRubius' YouTube channel, one of the most popular in Ibero-American countries. San José de Sumapaz (Colombia). © the author 2016.

The main objective of my analysis was to show the predominant audio-visual genres among the 10 most influential YouTubers whose content creation is completed in Spain. This top-10 ranking is extrapolated from a statistics website called SocialBlade.com, an independent website, whose main functions are to track social networks and offer statistics across multiple social media platforms. They are a leading provider of social media statistics that are freely available to anyone using their website. SocialBlade.com offers three different rankings about the most successful Youtuber channels worldwide, and by country: (1) Subscriber numbers, (2) video views, and (3) SB rank.

The SB ranking is provided because rankings based on subscriber numbers and number of views are not always an accurate indicator of what people are doing on YouTube. For example, a YouTuber can have many subscribers that can be fraudulently obtained without having any actual views. So, with the SB ranking system, you can discriminate these fake accounts, and measure a channel's influence based on various metrics. SB only assigns a channel an A++, A+, or A rank if it is influential.

This is a quantitative approach, but one that helped me to complete a qualitative final analysis. For this, I used the concept of polymediation that I described above. Polymediation is a term that refers to the numerous types of technology that users try and to the multiple ways in which they interact with technology. This summarizes the qualitative objective of my analysis, since YouTubers shape a kind of channel that is based on the fusion of different media and, above all, proposes a new form of interaction with users. From this perspective, my hypothesis is that YouTubers act as mediators between (poly)media convergence and users. I then examined how polymediation manifests itself in the Spanish case. For this, I analyzed the top 10 most influential YouTubers by combining SocialBlade's two quantitative metrics with their more qualitative metric.

The 10 top YouTubers in Spain sorted by the SB ranking are shown in Figure 2 [26].

**Figure 2.** Top 10 Spanish YouTubers sorted by SB Rank.

Only one of the current Spanish YouTubers achieves a blue A++, *TheChacal547* [37], who created his channel in 2014 (Figure 3).

**Figure 3.** Front page of the YouTube channel, TheChacal547.

The only description of this channel is that it "provides the craziest and funny videos", which are commonly called memes and viral videos. This Spanish YouTuber is extremely successful since they are third at the global level as per the SocialBlade grading. In this first example, the predominance is already evident of a highly decanted content towards humor and comedy, in its most childish aspect. Polymediation is also evident: First, in being a specific channel, it has different content windows with both real images and animation, tabs for the community, and related channels and buttons to link with other social networks, like Facebook and Twitter. These qualities were replicated in all the samples of my research. The only other Spanish YouTuber that approaches TheChacal547 in the Social Blade rank is elRubius, albeit in position #279 (Figure 4) [38].

**Figure 4.** Frontpage of the YouTube channel, elRubius.

Considering the total number of world subscribers, elRubius is in 18th position, ranking 92nd in the world in video views (Figure 5).

**Figure 5.** Youtuber, elRubius, in 18th position in terms of subscribers and 92nd in terms of video views worldwide. 5 May 2018.

On 5 January 2019, elRubius climbed up to 13th position (32 million subscribers) and VEGGETTA777 to 27th position (25 million subscribers). There were no other Spanish YouTubers in the global top 50. Some other Spanish language channels were listed: *HolaSoyGerman* (35 million subscribers) and their second channel, *JuegaGerman* (31 million subscribers), both from Chile, *Badabun* (31 million subscribers, Mexico), and *Fernanfloo* (31 million subscribers, El Salvador).

#### *3.1. Video Views*

The first chart (Figure 2) with the 10 top Spanish YouTubers is sorted by the SB ranking. However, when sorted by video views (Figure 6), there are some interesting changes.

**Figure 6.** Social Blade ranking according to video views.

In this case, only VEGETA777, elrubiusOMG, Mejores Juguetes, and Antena 3 (TV channel) remain on the list. I discarded the latter as it adds distortion because it is a Spanish national broadcaster with a relatively professional and large team that are responsible for its content. VEGETA777 is a videogame-type channel as you can see on their website (Figure 7) [39].

**Figure 7.** Front page of the YouTube channel VEGETTA777.

This is the description of this channel on their website: " PURPLE UNICORN ". The channel

description provided on the website is as follows: "This is a channel dedicated to video games directed by a guy [sic] who loves unicorns and lives with a killer elf in his room, if you subscribe to it you run the risk of falling into my madness, and it's not only me who says that, also the woman who appears at night on the roof of my room! A litle kisssss ˆˆ".

There is a significant narcissistic syntactic structure in which he refers to himself in the third person and, without a lack of continuity, he starts using the first person. Again, an appeal in a naïve style is used to appeal to very young users.

The third in the ranking with more video views is *Mejores Juguetes* ("Best Toys" in English) [40] (Figure 8).

Since this is a channel for little children where toys are unboxed, the channel is a paradoxical case of this childish style, although in the description, she says that "it is an entertainment channel for children of all ages and *even for their parents*" [40]. The channel also has an animation series, *La brujita Tatty* ("Little witch Tatty"); but the creator, a woman who lives in Barcelona, keeps her name a secret. *Future Internet* **2019**, *11*, 40

**Figure 8.** Front page of the YouTube channel, MEJORES JUGUETES.

#### *3.2. Subscribers*

Finally, regarding the number of subscribers, the majority of YouTubers from the original *SocialBlade* ranking disappear: Only elRubius and VEGETTA777 remain (Figure 9).

**Figure 9.** Social Blade ranking according to subscribers. Source: SocialBlade.com.

The key problem with this methodology is that it introduces distortions, like the aforementioned Antena 3, and does not resolve the problem of the weighting between video views and subscribers. So, I propose to cross all three possibilities without that kind of distortion, and to give preference to the SB rank according to their highest rank: A++ and A+. From this point on, I focus on video downloads and the number of subscribers, which is probably the most easily manipulated criterion. From this mixed method, I obtained a list of the 10 most relevant youtubers in Spain (Figure 10).

**Figure 10.** Social Blade ranking of 10 top Spanish YouTubers in descending order: SB Rank, video views, and subscribers.

The list in Figure 10 is a much more balanced list. In purple are the YouTubers that rise with respect to the original SB chart, and in red are those that descend. To even better balance the evolution of each Youtuber in these results, it would be helpful have the total visualizations since each one of these channels was created. In this case, the data are offered directly by YouTube (Figure 11).

In this case, the top ranked channel is VEGETTA777 closely followed by elRubius. However, the latter channel was three years younger (as of 5 May 2018) and only had 775 videos against the 4453 of the first. However, elRubius has seven million more subscribers. The YouTuber that follows in the ranking, Mejores Juguetes, has only one-third of the subscribers of the first two with only 1500 million views less than elRubius and the former was created three years later than this one.

The oldest channel—the first in the ranking—was created only 10 years ago, and the average age of these successful channels is approximately 4.5 years.

As for the evolution during the nine months since making the synchronous cut until 5 January 2019, the majority of cases are consistent in the first three positions: A growth of about 1%—2% per month in both subscribers and views, which accounts for the maturity of these channels in the top of the ranking. However, from fourth place down, the variability is much greater, with *Mikecrack* doubling the figures, or *Doggy Doggy Play Doh Cartoons* and *Las Ratitas* tripling these.

Finally, this table provides a current map of the audiovisual genres: The top positions belong to the stable non-child video games genre (meaning that they are aimed at adults). From the third position on, considerable variability is observed, with a clear tendency toward childish genres. I then examined this more closely.

**Figure 11.** Rank per total number of video views on 5 May 2018 of 10 top Spanish YouTubers in descending order. Source: YouTube.

#### *3.3. YouTubers Genres*

Socialblade.com uses these eight categories or macro-genres that would cover virtually all YouTuber content: (1) Autos and vehicles, (2) comedy, (3) education, (4) entertainment, (5) film, (6) gaming, (7) science and technology, and (8) shows. From these, only entertainment appears in the 10 Top Spanish YouTubers. To be more specific, I propose the subgenres that can be deduced from this group: (1) Memes (fiction and reality), (2) children (commercial products and videogames for children, gaming), and (3) videogame (gaming not only for children). These three sub-genres could be classified into the traditional genre of comedy. For this, I propose the chart provided in Table 1.

I also propose a tentative age distribution assuming that SB does not offer this service. Three large age groups were established: Young, adult, and old. I was then most interested in the thresholds, whose typology for the youth were divided into childhood (up to five years old), puberty or middle childhood (up to 12—14 years), and adolescence (until 19 or 20 years old) [41]. Therefore, given the generic content I analyzed, halfway between childhood and puberty may be a good limit, and this could specifically be eight years of age (Table 2).

**Table 2.** Tentative age distribution according to the number of subscribers and video views in the top 10 Spanish YouTubers (5 May 2018).

Note that the difference among the subscribers and video views is because, in Table 2, I included some of the Youtuber channels from several subgenres, as is the case of elRubiusOMG, since this channel is mainly dedicated to the commentary of videogames and to broadcasting the experience of elRubius himself playing. However, memes also have some weight in the total content, so it was difficult to classify the channel in a single sub-genre. The total number of subscribers by genre is provided in Table 3.

**Table 3.** Total number of subscribers per genre in the top 10 Spanish YouTubers (5 May 2018).

In this case, I added elRubiusOMG's figures only to the videogame column. The most important observation here is that the youtubers related to the videogames genre have the most subscribers: Almost double those related to children's content. The videogames genre could also be considered as being aimed at children; however, I think that the genre can be differentiated among the other main genres. An example is this photo captured from a video with 17,094,046 views [42] in the *Doggy Doggy Cartoons* channel (Figure 12), which shows the kind of YouTuber content that I think is exclusively aimed at children (under eight years old). The second picture was captured from a gamer video [43] published by elRubius (Figure 13), also childish, but maybe more aimed at children above the age of eight years.

**Figure 12.** *Superhero Babies at the Supermarket Hulk Frozen Elsa Play Doh Cartoons Stop Motion Movies*. © Doggy Doggy Cartoons.

To argue my hypothesis about the childishness of successful YouTubers' content, the video published by *Doggy Doggy Cartoons* has almost four million more views than elRubius'. Perhaps a corrective factor or handicap should be considered in favor of elRubius when considering the date of publication of both videos: 21 December 2017 and 8 May 2018. As, in both cases, several months have elapsed since its release, there seems to be no balancing effect or change that elRubius would overcome the number of video views of the first.

A final combination of all the collected quantitative data is provided in Table 4.

This table provides revealing data. Of the approximate total number of subscribers to successful Spanish YouTubers' channels (about 81 million) on the date of analysis, approximately 36% would be under eight years old (about 29 million) with genres focused on children's content, and the remaining 64% would also be focused on pseudo-childish content. From these data, I concluded that the average user of this kind of channel in Spain would be less than eight years old and consumes mainly children's content. If this relevant age category is not considered in terms of total numbers, the average Spanish subscriber would be older than eight years old and consumes content specifically related to videogames (aimed at them) and memes.

#### **4. Discussion and Conclusions**

In reference to my objectives proposed in this paper, I concluded that: (1) In terms of gender or/and sex visualization, most YouTubers are male. (2) The degree of originality can be considered as very low, due to both the uniformity of the content among the different channels and to the minimal variety of the narrative strategies and staging within each particular channel, which reminds us of primitive cinema. These are videos made with professional means of production, but whose creation tends to amateurism or, at least, to a certain immediacy. (3) To answer the question as to whether YouTubers' channels by themselves compose a totally new audio-visual genre, I think that these channels are a new audiovisual genre that, despite the minimal originality when compared with other YouTuber channels, display unique features, such as channels with polymediation, although these are not too developed.

To answer the question posed by McRobie [15], these YouTubers do not appear to have "a new radical voice". Instead, these channels resemble the Amazon-type monetization that is typical for YouTube content. However, these channels are also related to the monetization of self-centeredness or, as Duffy defined, to the mercantilization of a certain vocation related to the pregnant world of communication. This, when mixed with the different kinds of narcissism of YouTubers and the user themselves [3–7], exceeds what a Marxist critical analysis of mercantilist Neoliberalism could provide.

Burgess and Green [13], Jenkins [17], Sabich and Steinberg [18], and Lange [19] pointed out how YouTube is part of a participatory or connected culture—a community that, in most cases, is quite poor considering that it is mainly based on "likes" and "dislikes", and on a basic commentary chat structure below the video window. Polymediation would require a deepening in the philosophy of the concept, for example, with the possibility for the users to "comment" with their own produced videos, or editing the videos uploaded by each YouTuber. With even more open communication, all the possibilities of polymediation could be applied. The current structure of the Youtuber ecosystem reinforces the influence of the YouTuber and their success. However, I think that in the medium term, polymediation will be a major limitation of the creativity and evolution of this ecosystem based on the accentuated generational bias that requires a rethinking of the whole ecosystem.

My research has certain limitations, both at the quantitative and qualitative levels. Of the former, a limitation was caused by the data being gathered on a single day, though I was able to integrate a brief comparison with subsequent data nine months later (Figure 11). Even without this comparison, this quantitative level allowed me to observe a clear trend in the goal of classifying successful audiovisual genres. I provided a finding that may be significant, but needs to be tested in other research: The obvious user age bias that problematizes the future development of these YouTuber channels. Qualitative limitations are always inherent if simply compared with the quantitative methods, but the qualitative methods here were especially necessary given the youth of this phenomenon in which the data's historical series are limited. As such, qualitative data can contribute significantly to this field. Polymediation is speculative, but I think it can contribute to the understanding and future development of the YouTube phenomenon.

In summary, my analysis could have been more comprehensive if it had included a lengthened body of research, both temporarily extending the time slot as well as more nationalities. However, my goal was also to propose a method that could be applied by other researchers. I have proposed a straightforward method so the results can be replicated in other cultures.

To finish, the concept of polymediation can be related to the successful audiovisual subgenres in Spain that I deduced. These are based on content aimed at specific audiences and with an emphatic type of communication that is related to polymediation, as this is a type of communication with which it is possible to connect, to invent qualitative new content, or reinvent the type of contact between the YouTuber and the user on a daily basis. Polymediation is reinforced by the feeling of community and the verification of identities that these audiovisual genres imply, especially in children, but also in teenagers if video-games are considered.

The definition of polymediation also provides some interesting research questions, especially in relation to the new possibilities for both narrative and business. I am not referring only to something so direct as direct monetization—so common in economics studies on YouTubers—and their professional projects. Polymediation provides research avenues in many aspects, including even sociological research, considering Baumann's liquid modernity, such as when Calka sustains that polymediation shows how "the complex relationship between media, identity, and performance is necessarily in flux" [28] (pp. 27, 28). This flux that YouTubers are unconsciously building must be considered, although, given the style and content of the dominant genres in their channels, it is still an immature flow, but one that marks a clear path. If one agrees with Calka that our identities change with the changes in the technological landscape of the media (ibid.)—the continuous flow related to Baumann thought—one must consider the bias that mediates a large part of the adults in our society by specific YouTubers genres that indirectly and proportionally offer content that do not respond proportionally to the cultural richness of a culture that has been able to offer the most sophisticated communication network in history.

To the best of my knowledge, this is the first study in which polymediation was related to YouTube success. My results indicate that polymediation has not been fully developed in YouTube channels, a kind of audiovisual entertainment. I envision a difficulty and two possibilities. Firstly, according to the data I presented, this is a fairly mature market in which approximately the five top YouTubers have sufficient subscribers and views to live off the income and are able to set trends, so specificity is a difficulty for newcomers. As for the possibilities, both the YouTube platform and the analyzed channels are recent, and both have provided examples of creativity and flexibility since its creation, which are characteristics of polymediation. Seeking survival may produce radical changes in the medium term. Secondly, YouTube is the paradigm—although in its most basic expression—of polymediation. However, traditional on-line content platforms (OTT), such as Netflix or Amazon, are degrading the ecosystem of immediate consumption and in no entertainment area is YouTube the king. This can be expected to spur YouTube—and YouTubers themselves—to implement new polymediation features that would provide YouTube channels an advantage over OTTs. This advantage is yet to be seen, but the situation suggests that it will be along the lines of polymediation. When I was finishing this article, on 28 December 2018 Netflix had just released *Black Mirror: Bandersnatch*, the first interactive chapter of the series, in which the viewer makes decisions for the main character, being asked at various points to make a choice which affects the storyline [44]. I think that change will accelerate as the generational bias disappears, which is when the users of these channels aged. Considerably more work is needed to determine its further development.

More information on polymediation would help with the establishment of a greater degree of accuracy on this matter. My future lines of research will be developed along these lines, in trying to analyze how the possibilities offered by polymediation can be integrated into successful YouTube channels. I will analyze similar YouTubers' examples as proposed here, but from different cultures, such as the North American, Russian, or Chinese cultures. Later, I will compare the results to look for similarities and differences to verify to what extent the integration of polymediation can be generalized at the global level. My intent will be to propose a guide both methodological—for the analysis of

the YouTuber phenomenon—and professional to provide a minimum guideline of success for future YouTubers, as well as a sufficient ethical guideline that is globally valid.

The aim of the present research was to examine the predominant audiovisual genres of the successful YouTube channels in Spain and their relationship with polymediation. This led me to a discussion the creation of the identity of their users. This was not the focus of this paper, but from a sociological point of view, for example, from Bauman [45], identity is created from the various alternative offers that are present in our reality (p. 16). It is nowadays accepted that texts, those that surround us and compose our daily life, build our consciousness, and the quality of these texts qualitatively influence our identities. "The media supply 'virtual [...] substitute' and 'imagined extra territoriality' to the multitude of people who are denied access to real life" (p. 97). Therefore, my analysis expands the field of study mapped here from the data collected, as hypothesized. I attempted to think about polymediation in YouTuber channels beyond the technical possibility, for example, analysing how it can influence the creation of mature identities that can face the challenges of our liquid society.

From a more philosophical viewpoint, Byung-Chul Han [46] examined this possibility when claiming that the Internet does not really assist human intercommunication, but enables contact with peers and distances strangers and those who are different. Pariser thinks that all this would narrow our horizon as "we are entangled in an endless loop of the self and, ultimately, lead us to a 'self-propaganda that indoctrinates us with our own notions'" [47]. A further comprehension of what polymediation could add might help to overcome this level of childish self-centeredness.

**Funding:** This research was funded by Ministerio de Economía, Industria y Competitividad [Ministry of Economy, Industry and Competitiveness], Ref. CSO2016-74977-R. "Análisis del fenómeno Youtubers en España: Una exploración para identificar los vectores de cambio del mercado audiovisual" ["Analysis of the YouTubers Phenomenon in Spain: An Exploration to Identify the Vectors of Change in the Audio-visual Market"], 2016/00171/010, Proyecto I+d Plan Nacional. Universidad Rey Juan Carlos.

**Conflicts of Interest:** The author declares no conflict of interest.

#### **References**

© 2019 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

## *Review* **Open Data for Open Innovation: An Analysis of Literature Characteristics**

#### **Diego Corrales-Garay †, Eva-María Mora-Valentín \*,† and Marta Ortiz-de-Urbina-Criado †**

Facultad de Ciencias Jurídicas y Sociales, Universidad Rey Juan Carlos, Paseo de los Artilleros, s/n, 28032 Madrid, Spain<EMAIL_ADDRESS>(D.C.-G<EMAIL_ADDRESS>(M.O.-d.-U.-C.)

**\*** Correspondence<EMAIL_ADDRESS>Tel.: +34-91-495-9256

† These authors contributed equally to this work.

Received: 19 February 2019; Accepted: 20 March 2019; Published: 24 March 2019

**Abstract:** In this paper, we review some characteristics of the literature that studies the uses and applications of open data for open innovation. Three research questions are proposed about both topics: (1) What journals, conferences and authors have published papers about the use of open data for open innovation? (2) What knowledge areas have been analysed in research on open data for open innovation? and (3) What are the methodological characteristics of the papers on open data for open innovation? To answer the first question, we use a descriptive analysis to identify the relevant journals and authors. To address the second question, we identify the knowledge areas of the studies about open data for open innovation. Finally, we analyse the methodological characteristics of the literature (type of study, analytical techniques, sources of information and geographical area). Our results show that the applications of open data for open innovation are interesting but their multidisciplinary nature makes the context complex and diverse, opening up many future avenues for research. To develop a future research agenda, we propose a theoretical model and some research questions to analyse the open data impact process for open innovation.

**Keywords:** open data; open innovation; literature review; authors; journals; knowledge areas; methodological characteristics

#### **1. Introduction**

Since the beginning of the 2000s, the use of the term "open" has increased exponentially [1], giving rise to concepts such as open data, open innovation, open medical records system, open science, open knowledge, and open education, among others.

In 2003, Chesbrough proposed a new paradigm of the innovation [2,3]. For this author, open innovation constitutes a model where firms use both external and internal resources and commercialize both external and internal ideas/technologies [2]. Open innovation is defined as "The use of purposive inflows and outflows of knowledge to accelerate internal innovation, and expand the markets for external use of innovation, respectively. Open innovation is a paradigm that assumes that firms can and should use external ideas as well as internal ideas, and internal and external paths to market, as the firms look to advance their technology" [4] (p. 1). In that sense, open data is an external source that can be used for generating open innovation, and open innovations can create open data.

The open data concept alludes to "data that anyone can access, use, and share. Governments, businesses and individuals can use open data to bring about social, economic, and environmental benefits" [5]. Its annual economic impact is important to note: Open data potentially generate 900 billion dollars in the global economy [6], with a European Union market share increase of 36.9% between 2016 and 2020 [7]. Open data offer the potential for reuse, which produces new, innovative services for citizens and society in general [8,9]. Likewise, open data initiatives have an impact on aspects such as citizen engagement, transparency and innovation in the public sector [10].

We see then that open data can be a source to innovate. Some authors highlight that it is interesting to understand, in the context of open data and smart cities, how data-driven innovation is performed and its creation of social and economic value for the society [9,11]. Considering the interest of studying innovation in the context of open data and the importance of the openness phenomenon, we examine the possibility of using open data for open innovation. In that sense, we have searched articles that offer state-of-the-art ideas on that theme but have not found literature reviews that join open data and open innovation. Due to this, we have searched literature reviews of each theme to look for interest to study the combination of those two terms. We have found literature reviews about open data using different methodologies and temporal scopes [12–15]. Other studies analyse the literature on open innovation, combining several methodologies and temporal scopes, with 2017 being the last year analysed in the most current articles [16–25]. Finally, we have found that some of these studies have identified interest in the relationship between the terms "open data" and "open innovation" [12,14,17].

In that context, open data offers access to internal and external data that come from, mainly, public organisations. Governments and public agencies are liberating their data and they want open data to be used to solve problems and to create and improve products and services. However, access to open data in itself does not produce innovation [26]. New services, created by open data, mainly software applications, can be produced using a process known as open innovation, defined as "the opening of the innovation process to knowledge from outside the innovating organisation" [27] (p. 2), in which diverse agents such as citizens, companies, public entities, or academia collaborate to co-create these new services [28]. Thus, it is necessary to know how to implement open innovation using open data. A first stage to develop that idea is to review the previous literature.

In this paper, we have analysed the characteristics of the previous literature that has related open data with open innovation. We propose three research questions: (1) What journals, conferences and authors have published papers about the use of open data for open innovation? (2) What knowledge areas have been analysed in research on open data for open innovation? and (3) What are the methodological characteristics of the papers on open data for open innovation? To answer the first question, we use a descriptive analysis to identify the relevant journals and authors. To address the second question, we identify the knowledge areas of the studies about open data for open innovation. Finally, we analyse the methodological characteristics of the literature (type of study, analytical techniques, sources of information and geographical area). After answering these three questions, we will be better able to (a) identify who is who in that research line; (b) show the opportunities to implement open innovation to the agents of the open data ecosystem and (c) orient the new research about the use of open data for open innovation

#### **2. Methods Search Protocol**

The Web of Science (WoS) and Scopus databases were used to perform the literature review, since they are the most relevant databases in academia. While WoS included 20,000 indexed journals, Scopus included 21,950 [29].

The search protocol used is:

#### **3. Results**

#### *3.1. Descriptive Analysis*

Figure 1 presents the number of documents per year for the combination of the two topics studied. The first publications are from 2012 (4), and a certain growth can be seen from 2014 to 2017, with the highest number of documents appearing in 2015 (13) and 2017 (13).

**Figure 1.** Number of documents per year.

Table 1 shows the details of the documents identified in our analysis: authors, year of publication, title, citations in WoS, and Scopus and type of paper (articles: 28; conference papers: 27).

**Table 1.** Document analysis: Author/s, year/title/number of citations (WoS and Scopus).

#### **Table 1.** *Cont.*

#### **Table 1.** *Cont.*

A: Article; CP: Conference paper.

#### 3.1.1. Journals and Conferences

Tables 2–4 present the analysis of the documents according to type: articles or conference papers. Regarding articles (Tables 2 and 3), the "Information Polity" and "Government Information Quarterly" journals stand out with three and two articles, respectively. Regarding conference papers (Table 4), the book series "Lectures Notes in Computer Science" stands out with three documents. The other journals and sources only have one document each.

Note: NA: not available.

**Table 3.** Articles: journal/ranking, subject area and category SJR.

#### **Table 3.** *Cont.*

**Table 3.** *Cont.*

Note: NA: not available.

**Table 4.** Conference papers: source/ranking, subject area and category SJR \*.

#### **Table 4.** *Cont.*

NA: not available. \* Note: Information about conference papers ranking and categories JCR is not available.

We have analysed the different subject areas and categories of the Journal Citation Report (JCR) and Scimago Journal and Country Rank (SJR) (Tables 2–4). Most indicate a link with knowledge areas such as Information Technology and Computer Science and its offshoots. A review of the Computer Science subject area indicates the prevalence of the Computer Science Applications, Computer Networks, and Communication and Information Systems categories. Also prevalent are knowledge areas such as Public Administration and Government within the Social Sciences subject area, displaying a significant variety of associated categories: Sociology and Political Science, and Library and Information Sciences stand out, among others. Furthermore, knowledge areas such as Systems Engineering, Electronic Engineering or Electrical Engineering, among others (included

in the Engineering subject area), have a significant presence. The Technology and Innovation Management knowledge area also appears, mainly linked with the subject areas of Business, Management and Accounting, and Decision Sciences. Medicine, Molecular Medicine, Pharmacology, and Chemoinformatics have a minor presence. Finally, we must mention the knowledge area of Museology, under the subject area of Arts & Humanities. When analysing the journals ranked by JCR, eight are in the first or second quartile and by SJR, 20 are in the first or second quartile for the last available year (2017).

#### 3.1.2. Authors

Table 5 presents the most productive authors by affiliation and knowledge area. Several authors from the Nagoya Institute of Technology's Graduate School of Engineering (Nagoya, Japan) stand out with three publications each in the knowledge area of Computer Science: Tossavainen, Shiramatsu, Ozono and Shintani. Their publications focus on the use of web applications to promote collaboration between different interest groups (individuals or organisations) for the purpose of solving public and social problems [68,72,73].

#### **Table 5.** Top authors (affiliation and knowledge area).

#### **Table 5.** *Cont.*

Authors that focus on this topic belong to three knowledge areas: Computer Science, Information Technology and Economics (Table 5). Some authors such as Yoshida, Lee and Choi belong to two knowledge areas, Economics (focus in the open innovation research) and Information Technology or Computer Science (focus in the open data research). The affiliations of the top authors are Japanese (six), Swedish (four), Spanish (three), Finnish (three), Korean (three) and Taiwanese (three).

#### *3.2. Studied Themes by Knowledge Area*

We analysed the knowledge areas considering the SJR subject areas and categories. In the Information Technology and Computer Science knowledge areas, topics such as the development of open innovation processes through web platforms are the most commonly studied [72,73]; other topics include the impact of the use of open government data to improve or produce new products and services, as well as the open innovation processes derived from the use of these data [71]. This last topic has also been addressed in knowledge areas such as Public Administration, along with other topics such as open data, transparency, civic engagement, and public sector innovation [10].

Regarding the knowledge areas of Systems Engineering, Electronic Engineering, Electrical Engineering, the most prevalent topics are the development of systems that offer a service to the user and that enlist the collaboration of these users to improve the product, thus involving various stakeholders in a co-creation process [56]. For Technology Management and Innovation, topics addressed include the management of technology innovation processes in organisations [32], or the phenomena of co-creation and innovation promotion [75].

In the knowledge areas of Medicine, Molecular Medicine, Pharmacology and Chemoinformatics, the positive impact of open data and open innovation on drug discovery and development processes is analysed [77,79]. Lastly, in Museology, the impetus of open data and open innovation in museums, libraries and archives is discussed [63].

#### *3.3. Methodological Characteristics of the Documents*

To perform a more in-depth literature review, this section presents an analysis of the methodological characteristics of the documents studied as the type of study, the analytical techniques, the source of information and the geographical area.

Analysing the type of documents indicates that 65.5% (36) are empirical and approximately 34.5% (19) are theoretical. Several aspects of the empirical documents have been analysed, such as the type of study (Table 6), analytical techniques used (Table 7), and sources of information (Table 8).

Tables 6 and 7 show that 61% (22) of the empirical documents are exclusively qualitative studies using the analytical technique of case study. On the other hand, six documents (approximately 17%) are exclusively quantitative, using analytical techniques such as the varimax rotation method, correlation coefficients, Cronbach's alpha coefficient, regression analysis, structural equation modelling, and descriptive statistics. Furthermore, seven documents (approximately 19.4%) use a combination of quantitative and qualitative techniques. All are case studies with various types of descriptive statistics, except for one by Smith & Sandberg, 2018 [69], that combines a case study with a cross-tabulation matrix. If we analyse all the studies that are exclusively quantitative or that are combined with a qualitative study, 13 documents are found (36% of the empirical documents). Eight of these are cross-sectional studies for the same period, and five are longitudinal studies.

**Table 6.** Type of study/author/s, year.

**Table 7.** Analytical techniques/author/s, year.

The most prevalent analytical technique used is the case study, identified in 28 documents (77.8% of the empirical studies), followed by descriptive statistics found in nine documents (25% of the empirical studies) (Table 6).

Table 8 presents the information sources used in the empirical studies. Most (28, or 77.8%) of the documents analysed have a secondary source; 16 documents (44.4%) have only one source; and 8 documents (22.2%) have three or more sources. Primary sources are found in 18 (50%) of the empirical studies; 8 (22.2%) have a single primary source and 9 (25%) have two primary sources.

Table 9 shows that 60% of the documents (33) correspond to a single geographic area, while 18.2% (10) correspond to several geographic areas. Approximately 21.8% (12) of the documents do not indicate any geographic scope. The geographic areas represented are widely scattered, although approximately 53% (29) of those that indicate a geographic area are analyses conducted in Europe.

**Table 8.** Sources of information/author/s, year.

**Table 9.** Geographical area/author/s, year.

**Table 9.** *Cont.*

#### **4. Discussion**

After analysing the characteristics of previous literature that jointly analyses open data and open innovation, we discuss the different knowledge areas focused on this topic. We observe that open data and open innovation studies are addressing the topic from different perspectives. While open data has been analysed under the Computer Science, Engineering and Public Administration disciplines, open innovation has been developed in the Management and Innovation subjects. Subsequently, we develop these arguments according to the knowledge areas identified in our analysis.

Knowledge areas such as Information Technology and Computer Science help to understand how the data must be (characteristics, quality ... .) and the format in which data have to be published for performing open innovation. Additionally, we think that it is necessary to deepen the study of the data publishing mediums (platforms, webs ... ) and their utility for performing open innovation. On the other hand, it is interesting to know how the data can be reused for performing open innovation. So, literature focused on the Public Administration area offers a framework which allows us to analyse the ecosystem of reusers and the products and services that can be obtained under the open innovation paradigm.

Regarding the Management and Innovation subjects, previous literature shows theoretical open innovation models that can be adapted for studying the use of open data for performing open innovation. More empirical studies that develop applications about this topic are necessary. In some knowledge areas such as Systems Engineering, Electronic Engineering, Electrical Engineering, Medicine, Molecular Medicine, Pharmacology and Chemoinformatics, and Museology, the case study methodology is too frequent. These papers offer cases or examples of open innovation activities obtained from open data.

In our descriptive analysis, we have found no documents about the state of the art about open data and open innovation jointly. Even though the previous literature focuses on the study of some specific aspects in different knowledge areas, there are no papers that develop theoretical frameworks that help to understand the use of open data for generating open innovation.

In this context, we have developed a theoretical model, which includes some dimensions of previous models of open data and open innovation. On the one hand, following Abella et al. (2019) [80], we have used the open data impact process and the reusers categories of open data. The model presents a process with four phases: 1. Candidate data; 2. Published data; 3. Reused data; and 4. Impact; and proposes a classification of data reusers in three groups: (1) primary open data source (public organizations and other related organizations that publish open data); (2) direct reusers (social and professional); and (3) end users (social, citizen, professional and academic). On the other hand, following Gassmann and Enkel (2004) [81] and Nerone, Canciglieri Junior, Steiner and Young (2014) [82], we have considered two types of open innovation: inbound (to insource external ideas and technologies to enhance products' values) and outbound (to outsource internal resources for refining, exploiting and bringing them to market). We also consider the two types together, or coupled (a combination of the inbound and outbound processes). Our model is the first theoretical proposal for the study of the use of open data for open innovation (Table 10).

#### **5. Conclusions**

There is growing interest from both academic and professional scenarios of studying the innovation topic under the perspective of openness [83] and the reuse of open data [80]. One of the main effects of this reuse is the possibility of innovating and creating new businesses or developing new products or services for citizens [8,9]. Therefore, these two concepts are fully related and it is necessary to deepen, from the academic context, in their joint study in order to guide to the managers to take advantage of open data and open innovation.

Literature reviews are very useful to know the state of the art about a topic. In this sense, we have found some literature reviews about open data or open innovation, but there are still no studies that jointly analyse both topics. This paper tries to cover this gap in the literature by formulating three research questions. To this aim, we have carried out a search of the papers that include open data and open innovation research. We have identified just 55 documents. Many of them are in the initial stages of the research because they are conference papers. It seems logical to say that the joint study of these two topics is emerging and that several documents have not yet been published but are being presented in various academic and professional forums.

To answer the first research question, two analyses have been carried out. Firstly, we have identified the main journals and conferences that publish papers on these topics. The results show that the documents are published in journals of different knowledge areas, Computer Science and Engineering and Public Administration that analyse the issue of open data. Other knowledge areas are focused on open innovation such as Business, Management and Accounting or on the practical applications that have the use of open data to perform open innovation, as is the case of applications or examples of its use in knowledge areas related to Health Sciences, Engineering or the knowledge area of Museology. Secondly, the paper identifies the authors that have published in these issues. It is observed that there is still little productivity per author (maximum three articles), which confirms that this line of research is in its initial stages. The authors are related to knowledge areas as Computer Science, Information Technology and Economics. If we consider their affiliation, the authors of research institutions of Japanese, Korean or Taiwanese universities stand out. There is also a presence of European researchers (Spanish, Finnish and Swedish) among the top authors.

To answer the second research question, knowledge areas are analysed. The main conclusion is the multidisciplinary character of this topic. The most outstanding knowledge areas are Information Technology and Computer Science. Also, from other areas such as Public Administration, Business and Management, and Medicine, papers are being carried out focused on aspects more related to management issues and the application of open data to open innovation.

Regarding the third research question, it is observed that although it is an emerging topic, most of the papers (65.5%) are empirical. This result highlights the need to carry out more theoretical studies that help lay the foundations and the theoretical bases to jointly study these two issues. Moreover, most of the empirical papers are qualitative (61%), which is consistent with the state of development of the research line. The most used technique is the case study. This methodology helps to understand, solve or improve a professional world procedure [84] and is appropriate when the phenomenon investigated is exploratory and descriptive and when primary information is available. As the literature is not conclusive, it is necessary to carry out an in-depth and qualitative analysis on the topic. In this sense, it is observed that 50% of the articles analysed use primary information sources and there are some that combine primary and secondary. The case method also allows applying the inductive method to propose propositions or theoretical hypotheses based on practical experience and examples of application of open data use to open innovation. Finally, results show that the studies have been carried out in different geographical areas. This shows the global reach of these issues, which, besides being applicable in different areas of knowledge, are also applicable in different geographical areas.

The joint analysis of open data and open innovation can be studied considering three dimensions: (1) the main phases of the open data process, (2) the types of open innovation that can be developed with open data, and (3) the ecosystems of reusers that are the agents that make the open innovation

possible. In that sense, we have proposed a theoretical model to analyse the open data impact process for open innovation. This model can be a guide to future research and help us to present some future research lines and questions. Future research can analyse the following questions for each phase of our theoretical model (Table 10). Phase 1: How does outbound open innovation select the candidate open data? What is the role of public administrations in the selection of open data for outbound open innovation? What effect do the open data policies of each country have on the opportunities to perform open innovation by both public and private institutions? How can the FAIR principles for scientific data—findable, accessible, interoperable and reusable—[85] be adapted to the context of open data for open innovation? Phase 2: How does outbound open innovation publish open data? What is the role of public administrations in the publication of open data for outbound open innovation? How can models developed for innovation in open science such as European Open Science Cloud (EOSC) [86] be adapted to the open data for the open innovation context? Phase 3: What forms of open data reuse are more suitable for open innovation? What is the inbound innovation of each reuser like? and Phase 4: What economic and social effect does the use of open data have in making open innovation? What is the social, economic and technological impact of each type of open innovation? What is the social, economic and technological impact for each reuser? And, in addition, some future research is necessary to develop theoretical and practical applications and examples from a holistic perspective considering all the aspects included in our theoretical model. In that sense, other research questions have been raised by our study. What topics have been the most studied? What are the theories that can be applied to study this phenomenon? What opportunities for open innovation do open data offer? What are the barriers when using open data for open innovation?

This paper presents some theoretical and practical implications. The paper analyses the main aspects of the previous literature that has combined the terms open data and open innovation: journals, conferences, authors, knowledge areas and methodological characteristics. Our results are useful for researchers who start to research this topic because they identify existing gaps and propose new research questions. In addition, "open innovation can help to identify opportunities for entrepreneurs" [87] (p. 2). In that sense, the paper can be useful as a starting point for agents such as citizens, companies or public institutions that want to carry out an open innovation activity such as the creation of digital applications and services through the reuse of open data.

Finally, the paper has some limitations. Other techniques can also be used in order to complete the descriptive analysis, such as bibliometric techniques (bibliographic coupling, co-citation analysis or co-author analysis) that would provide additional information and alternative approaches to describe how state-of-the-art this topic is.

**Funding:** This research was funded by the Spanish Ministry of Economy and Competitiveness [grant number ECO2015-67434-R].

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

MDPI St. Alban-Anlage 66 4052 Basel Switzerland Tel. +41 61 683 77 34 Fax +41 61 302 89 18 www.mdpi.com

*Future Internet* Editorial Office E-mail<EMAIL_ADDRESS>www.mdpi.com/journal/futureinternet

MDPI St. Alban-Anlage 66 4052 Basel Switzerland

Tel: +41 61 683 77 34 Fax: +41 61 302 89 18


**3. Morphological identification of bifidobacteria by phase contrast microscopy (PCM)**

In the morphological analysis of bifidobacteria population, *in situ,* in human faeces and/or other foods products, microscopes have been used to determine the degree of heterogeneity of these probiotic's populations. The morphology of bifidobacteria determined microscopically has been used as an aid to phenotypic differentiation within the group, while the effect of medium type, low pH and high bile salt concentrations on the bifidobacterial cell morphology has also been studied by this method. Individual

*Bifidobacterium* strains are characterized phenotypically, including morphology identification by phase contrast microscopy (PCM).

*Bifidobacterium* in Human GI Tract:

Screening, Isolation, Survival and Growth Kinetics in Simulated Gastrointestinal Conditions 289

curvature of this isolates when grown on RB agar, is a powerful diagnostic feature, particularly when distinguishing this specie from closely related *B. minimum* when grown on Trypticase-Phytone-Yeast extract (TPY) agar stabs (Biavati *et al.,* 1982). In addition, curved cells with smooth and rounded ends are the most one dominating in the micrograph. These features were not compatible with descriptions of this particular species' morphology as described by

The *B. infantis* strain displayed slender, often short rod-shaped and of the typical clubshaped extremities, which cells of these species are reported to exhibit (see Figures 4.3 & 4.4). The morphology of this strain is almost the same when grown on both the MRS and RB solid growth media. Furthermore, *B. infantis* showed a distinct tendency for chain formation on RB medium. These cells often occurred in "V" and "Y"-shapes and were similar to that of many other species of the genus. Nevertheless, it was also possible to differentiate between this strain and the closely related *B. longum* GB-03 (own isolate, Fig. 4.6) on the basis of small

Morphological consistency is greater among the *Bifidobacterium* isolate (*B. longum* GB-03 and *B. bifidum* WN-04) as shown in Figures 4.5 to 4.11) than the *Bifidobacterium* reference strains. Cell shapes ranged from long and thick–rods with protuberances to long and thin–rods with blunted ends and slightly bifurcated club-shaped extremities, with a number of variations on these basic shapes. Two morphological groups and their potential significance are

Figures 4.6 and 4.8 display both isolates of *B. longum* GB-03 and *B. bifidum* WN-04 on RB medium, which consisted of long and thick cells with slight bends. The regular morphology of these cells and the star-like aggregates arrangement (Figure 4.6) was evident under the PCM when grown on RB agar. Also, the presences of sparsely distributed single cells were also evident under the PCM (Figure 4.8). The morphology of these cells was consistent with any of the *Bifidobacterium* reference strains discussed previously. The isolates' morphologies resembled the reference strain of *B. infantis* which are never elongated but have a penchant

Although no conclusions could be drawn on the basis of morphology alone, the presence of "V"-shaped rods, protuberances with a large variety of bending in *B. bifidum* WN-04 isolate appeared to resemble the reference strains of *B. bifidum*, especially the "amphora-like" cells that are characteristic (Sundman & Bjorksten, 1959). On the RB media, PCM analysis allowed a better correlation of the natural isolates to the reference strains. Speciation of *B. longum* GB-03 (in Figure 4.6) conversely appeared to favour the reference strain of *B. longum*, especially the ultra-elongated and relatively thin cellular elements with slightly irregular

Reuter (1963), but were common to other species of the genus.

**3.2. Morphological differentiation of isolates of bifidobacteria**

*3.2.1. Long and thick–rods with protuberances cell morphology*

variety of club-shaped extreme morphology.

discussed separately below.

for group formation (Figure 4.4).

contours (Reuter, 1963).

Bifidobacteria are gram-positive, anaerobic, rods of various shapes (short, regular, thin cells with pointed ends, coccoidal regular cells, long cells with slight bends or protuberances) or a variety of branching (pointed, slightly bifurcated, club-shaped or spatulated extremities), single or chains of various arrangements (in star-like aggregates or disposed in "V" or "Y" or else "palisade" arrangements) (Scardovi, 1986).

As a pattern to characterize the heterogeneous population of bifidobacteria associated with human origin and other sources, the PCM examinations and two different media (RB & modified MRS) were used to demonstrate a better phenotypical correlation of the natural isolates to the reference strains on RB, MRS and modified MRS media as shown in Figures 4.1 – 4.12). These media are unique and appear to be still the most predominant in culturing the bifidobacteria strains.

Isolates of bifidobacteria are normally cultured anaerobically on appropriate agars at 38 ºC for 3 – 4 days. For gram-staining, a loopful of the culture is streaked on microscope slides (46 × 25 mm) and the staining technique followed thoroughly. Subsequently, the slide is observed under phase contrast microscopy, preferably at 1000 magnification by oil immersion and can be photographed as well, using the images advanced software package if available.


**Author details**

Mansour Al Qubeissi1 \*, Nawar Al-Esawi1 and Ruslana Kolodnytska2

\*Address all correspondence to<EMAIL_ADDRESS>
1 Centre for Mobility and Transport, Faculty of Engineering, Environment and Computing, Coventry University, Coventry, United Kingdom

[4] US Department of Energy: Energy Efficiency and Renewable Energy. Biodiesel Blends. 2015. http://www.afdc.energy.gov/fuels/biodiesel\_blends.html [Accessed July 29, 2017] [5] EPA U. US Environmental Protection Agency 2014. http://www.epa.gov/ [Accessed July

Atomization of Bio-Fossil Fuel Blends http://dx.doi.org/10.5772/intechopen.73180 79

[6] Yuan W, Hansen AC, Zhang Q. Predicting the physical properties of biodiesel for combustion modeling. Transactions of ASAE. 2003;**46**:1487-1493. DOI: 10.13031/2013.15631 [7] Pearson RJ, Turner JWG. Using alternative and renewable liquid fuels to improve the environmental performance of internal combustion engines: Key challenges and blending technologies. Alternative Fuels and Advanced Vehicle Technologies for Improved Environmental Performance, Elsevier. 2014:52-89. DOI: 10.1533/9780857097422.1.52 [8] Brunschwig C, Moussavou W, Blin J. Use of bioethanol for biodiesel production. Progress in Energy and Combustion Science. 2012;**38**:283-301. DOI: 10.1016/j.pecs.2011.11.001 [9] Sazhin SS. Modelling of fuel droplet heating and evaporation: Recent results and

unsolved problems. Fuel. 2017;**196**:69-101. DOI: 10.1016/j.fuel.2017.01.048

6907. DOI: 10.1016/j.ijheatmasstransfer.2012.07.003

Transfer. 2002;**45**:495-507. DOI: 10.1016/S0017-9310(01)00173-9

que. 2009;**337**:449-457. DOI: 10.1016/j.crme.2009.06.004

DOI: 10.1016/S0017-9310(03)00286-2

10.1007/s10765-006-0113-7

DOI: 10.1016/j.jtice.2013.06.021

[10] Al Qubeissi M. Heating and Evaporation of Multi-Component Fuel Droplets. Stuttgart:

[11] Samimi Abianeh O, Chen CP. A discrete multicomponent fuel evaporation model with liquid turbulence effects. International Journal of Heat and Mass Transfer. 2012;**55**:6897-

[12] Ra Y, Reitz RD. A vaporization model for discrete multi-component fuel sprays. International Journal of Multiphase Flow. 2009;**35**:101-117. DOI: 10.1016/j.ijmultiphaseflow.

[13] Zhu G-S, Reitz RD. A model for high-pressure vaporization of droplets of complex liquid mixtures using continuous thermodynamics. International Journal of Heat and Mass

[14] Laurent C, Lavergne G, Villedieu P. Continuous thermodynamics for droplet vaporization: Comparison between gamma-PDF model and QMoM. Comptes Rendus Mécani-

[15] Grote M, Lucka K, Köhne H. Multicomponent Droplet Evaporation of Heating Oil Using a Continuous Thermodynamics Model. Lisbon, Portugal: V ECCOMAS CFD; 2010 [16] Burger M, Schmehl R, Prommersberger K, Schäfer O, Koch R, Wittig S. Droplet evaporation modeling by the distillation curve model: Accounting for kerosene fuel and elevated pressures. International Journal of Heat and Mass Transfer. 2003;**46**:4403-4412.

[17] Smith BL, Bruno TJ. Advanced distillation curve measurement with a model predictive temperature controller. International Journal of Thermophysics. 2006;**27**:1419-1434. DOI:

[18] Qi DH, Lee CF. Influence of soybean biodiesel content on basic properties of biodieseldiesel blends. Journal of the Taiwan Institute of Chemical Engineers. 2014;**45**:504-507.

29, 2017]

WiSa; 2015

2008.10.006

2 Faculty of Mechanical Engineering, Zhytomyr State Technological University, Zhytomyr, Ukraine


**4.3 Finish rolling at no-recrystallization temperatures**

As has been elucidated above, no-recrystallization temperature (TNR) is important in design of controlled rolling process. This temperature determines where strain is multiplied for austenite grains, leading to strain-induced precipitation of carbonitrides as well as enhanced sites for a fine-grain size ferrite to be nucleated at the sites.  The influencing factors for TNR are composition of the steel, strain values applied in each pass, the strain rate, and the rolling interpass time [7, 8].

During finish rolling the value of TNR tends to dynamically lower down as the strain value or the reduction increases. This phenomenon is attributable on account of static recrystallization caused by increased recrystallization sites owing to finer grains and higher dislocation density induced during each rolling pass.

The strain rate value is also a determining factor for the onset of dynamic recovery and facilitates static recrystallization which eventually decreases the TNR.

During controlled rolling, the interpass time during each rolling reduction also plays an important role as the prime requirement is to roll below TNR temperatures. The precipitation kinetics are accelerated due to strains induced when rolling below TNR. A lower interpass time is preferable as higher interpass will lead to coarsening of precipitate sizes as well as increased tendency of recrystallization detrimental to final strength value of steel.

### **4.4 Accelerated cooling**

**3.1 Addition of niobium, titanium, and vanadium**

growth are particle pinning and solute drag.

boundaries and inhibit their movement.

**3.2 Manganese-based strengthening**

carbonitrides and vanadium nitrides.

methods require simultaneous addition of V and Nb.

**4. Effect of controlled hot rolling parameters**

**4.1 Reheating temperatures at reheating furnace**

and nitrides that restrict initial austenitic grain size.

grain size by reduction at lower temperatures.

**228**

**4.2 Repeated recrystallization in roughing mill**

dislocation movement.

*Welding - Modern Topics*

Microalloying elements such as niobium, titanium, and vanadium are principally carbide-forming elements. Although the addition of these elements in steel raises its Ar3 temperature, they retard austenite transformation to ferrite by restricting carbon diffusion. Strengthening by addition of one or all of niobium, vanadium, or titanium has shown a remarkable increase in strength of steel. The strengthening phenomenon is caused by fine precipitation of nitrides, carbides, or carbonitrides which are coherent with ferrite matrix but induce strengthening by impeding

One of the most significant effect of adding individually or simultaneous addition of V, Nb, and Ti is to decrease recrystallization temperature. Which contributes

The two principal mechanisms that inhibit recrystallization and eventually grain

The grain boundary movement can be accounted on strain-induced precipitation

In the case of vanadium addition, addition of nitrogen can be helpful in increas-

The improvement of toughness can be achieved through addition of manganese that leads to decrease in Ar3 temperature. Due to decrease in Ar3 coupled with low coiling temperatures, the alpha (ferrite) grains are refined, thus increasing the strength. Additionally, the fine precipitate size is contributed by niobium

In general, austenitic grains starts to recrystallize at temperatures above 1050°C.

Eventually, a lower slab reheating temperature by contributing fine austenitic grain size and lower temperature rolling at roughing mill will induce even finer

Due to repeated reduction in roughing mill, both recrystallization and precipi-

tation are competing phenomena. However, at higher temperatures

Since an initial finer gamma grain size is helpful in creating a final finer size of alpha, lower reheating temperatures are effective. Also, the microalloying elements also add to refinement of the austenitic grain size by means of undissolved carbides

in generating a finer size of gamma (austenite) grains during finish rolling.

of micro carbides on gamma grain boundaries that limit the gamma grain size. Addition of titanium or niobium helps in suppressing gamma grain growth by means of nitride or carbonitride precipitates which are majorly present at grain

ing the strength and toughness. The vanadium nitride precipitates are useful in imparting strength to the steel. The addition of nitrogen however attributes to poor weldability. Likewise, the strengthening may be achieved by adding niobium, but a higher niobium content is bound to give poor weldability. Hence the conventional

> The runout table and the coiler in general act like post heat treatment unit which makes possible to achieve phase transformation through control of cooling to generate coils with varied properties and microstructures.

> Accelerated cooling after hot rolling leads to further refinement of grains and phase control, leading to enhancement of properties. The phenomenon for strengthening of microstructure is phase transformations in terms of microstructures avoiding pearlitic transformations, precipitation strengthening through carbides, and nitride precipitates which along with controlled cooling rates lead to the refinement of grain size in the resulting microstructure. The accelerated cooling may be classified into two techniques—continuous accelerated cooling and interrupted accelerated cooling.

> The final mechanical properties after accelerated cooling are majorly influenced by the alloying content and hot rolling parameters.

*Welding - Modern Topics*


**2.1 FRP hull**

Hull construction using FRP is very common for speed boats, small to medium size (8–80 m) patrolling boats, research ships for acoustic and underwater mapping studies, coastal ships, corvettes, etc. [1–4]. A very comprehensive list of literature is given by Galanis [3] in his M.S. thesis. One very interesting naval ship is mine countermeasure vessel (MCMV) which is about 60 m long [1]. MCMV uses passive magnetic sensors to detect underwater mines, which use a magnetic sensor to trigger the mine. Therefore, the ship as such should not have any magnetic signature. Conventional hull material of MCMV is nonmagnetic steel. However, FRP is preferred because of lightweight and corrosion-free nature in addition to nonmagnetic character. Miller [4] reported one such MCMV of Royal Navy (U.K.) made of GFRP way back in 1973 and a bigger one (60 m long) in 1980s. FRP is being used since World War II by the United States in noncritical areas and small boats [2]. Till now, large commercial or Naval ships such as Frigates, etc., are not made with FRP. The FRP hull of ships of 60–80-m size is a sandwich construction with thick FRP skin and a foam core. Thickness of the FRP skin on both sides of the foam core can be 8–10 mm each, and the foam core can be 50–80 mm thick. Previously PVC foam core was very common. However, with the large variety of polyurethane foam available today, even fire-retardant type including polyisocyanurate-modified polyurethane [5], the scope and ease of foam filling in between two hull panels have facilitated production system, and also large seamless foam core is easily made by foam spray machine.

Generally, unsaturated polyester made with isophthalic acid and neopentyl glycol and epoxy-based vinyl ester resins is widely used for marine boats and ship hull. Both of these resins are cross-linked by styrene monomer to form a thermosetting polymer.

FRP hull of boats of maximum 8 meters contains six types of fiber and fabric layers arranged in a sequence and requires minimum 25 layers of reinforcing mats and fabrics. The different fiber-based layers are random chopped strand mat, 300–450 GSM, woven roving mat 400–600 GSM, fabric of different thicknesses (approximately 0.25 mm), core mat of 1 mm and 3 mm thickness, and a 1 mm skin layer of the resin with particulate fillers (titanium dioxide, aerosil, barytes, etc.). Aerosil (fumed silica) is used with the resin to make it more impermeable to water. However, aerosil makes the resin somewhat thixotropic. Due to large size, and to

make seamless hull, wooden mold is first made, and hand lay-up technique is used for fabrication. In an elaborate arrangement, vacuum bagging or vacuum-assisted resin infusion can be used for at least small boats. Vacuum-assisted molding can make composite with about 70% fiber and 30% resin, which is obviously advantageous for strength.


**Author details**

Abhishek Kaul IBM, Singapore

\*Address all correspondence to<EMAIL_ADDRESS>
© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


**2. Clinical features**

#### **2.1. Symptoms**

In the absence of secondary infection, symptoms are minimal and include mild foreign body sensation in the eyes, occasional lacrimation, slight stickiness of the lids and scanty mucoid discharge. In the presence of secondary infection symptoms of acute mucopurulent conjunc‐ tivitis develop.

#### **2.2. Signs**

#### *2.2.1. Conjunctival*

and caruncle. Sometimes, follicles may be seen on the bulbar conjunctiva. Follicles are formed due to the scattered aggregation of lymphocytes and other cells in the adenoid layer. Central part of each follicle is made up of mononuclear histiocytes, few lympho‐ cytes and large multinucleated cells called Leber cells. The cortical part is made up of zone of lymphocytes showing active proliferation. Blood vessels are present in the most peripheral part. In later stages signs of necrosis are also seen.

#### *2.2.2. Corneal*

Pannus may be progressive (infiltration of cornea is ahead of vascularization) or regressive also termed pannus siecus (vessels extend a short distance beyond the area of infiltration).

#### **2.3. Differential diagnosis**

**1.** Presence of large multinucleated Leber cells and signs of necosis differentiate trachoma follicles from Adenovirus follicles conjunctivitis.

The distribution of follicles in trachoma is mainly on upper palpebral conjunctiva and for‐ nix. Sometimes, follicles may be seen on the bulbar conjunctiva.

The corneal involvement of the disease includes lymphoid follicle formation at the limbus. This is a characteristic feature of trachoma and can lead to the development of Herbert's pit.

Associated signs such as papillae and pannus are characteristic of trachoma.

**2.** Trachoma with predominant papillae is differentiated from palpebral form of spring ca‐ tarrh as follows:

Papillae are large in size and usually there is typical cobble-stone arrangement in spring ca‐ tarrh.

The pH of tears is usually alkaline in spring catarrh, while in trachoma it is acidic.

Discharge is ropy in spring catarrh

and caruncle. Sometimes, follicles may be seen on the bulbar conjunctiva. Follicles are formed due to the scattered aggregation of lymphocytes and other cells in the adenoid layer. Central part of each follicle is made up of mononuclear histiocytes, few lympho‐ cytes and large multinucleated cells called Leber cells. The cortical part is made up of zone of lymphocytes showing active proliferation. Blood vessels are present in the most

**3.** Papillary hyperplasia: Papillae are reddish, flat topped raised areas which give red and velvety appearance to the tarsal conjunctiva. Each papilla consists of central core of nu‐ merous dilated blood vessels surrounded by lymphocytes and covered by hypertrophic

**4.** Conjunctival scarring may be irregular, star-shaped or linear. Linear scar present in the

**5.** Concretions may be formed due to accumulation of dead epithedial cells and inspissat‐

**2.** Herbert follicles refer to typical follicles present in the limbal area. These are histologi‐

**3.** Pannus which is an infilteration of the cornea associated with vascularization, can de‐ velop at any point along the limbal margin but is most pronounced at the superior lim‐ bal margin. The vessels are superficial and lie between epithelium and Bowman's

Pannus may be progressive (infiltration of cornea is ahead of vascularization) or regressive also termed pannus siecus (vessels extend a short distance beyond the area of infiltration).

**4.** Corneal ulcer may sometimes develop at the advantage of pannus. Such ulcers are usu‐

**5.** Herbert pits are the oval or circular pitted scars, left after healing of Herbert follicles in

**6.** Corneal opacity may be present in the upper part. It may even extend down and in‐

**1.** Presence of large multinucleated Leber cells and signs of necosis differentiate trachoma

The distribution of follicles in trachoma is mainly on upper palpebral conjunctiva and for‐

volve the papillary area. It is the end result of trachomatous corneal lesions.

peripheral part. In later stages signs of necrosis are also seen.

epithelium.

232 Common Eye Infections

*2.2.2. Corneal*

the limbal area.

**2.3. Differential diagnosis**

sulcus subtarsalis is called Arlt's line.

cally similar to conjunctival follicles.

ed mucus in the depressions called glands of Henle.

**1.** Superficial Keratitis may be present in the upper part.

membrane; and later on the Bowman's membrane is destroyed.

ally shallow which may become chronic and indolent.

follicles from Adenovirus follicles conjunctivitis.

nix. Sometimes, follicles may be seen on the bulbar conjunctiva.

The corneal involvement of the disease includes lymphoid follicle formation at the limbus. This is a characteristic feature of trachoma and can lead to the development of Herbert's pit. In trachoma, there may be associated follicles and pannus.