2.3.2. Bristol

Located in the south-west England, predominantly on a limestone area, Bristol is one of the most densely populated parts of the UK and, after London, the second largest city in the southern region. Most of the urban extent of Bristol is based around the watercourses and river network, with two major rivers flowing through the city (Avon and Frome rivers), resulting in a characteristically hilly landscape. It is one of the warmest cities in the UK and there is a relatively even distribution of rainfall throughout the year, although the autumn and winter seasons tend to be the wettest. Within this context, Bristol has been investing in plans to create and improve resilient systems to tackle its various urban challenges. Based on the analyses conducted by local and international actors working on resilience, the main urban challenges in Bristol can be profiled firstly in terms of natural and environmental hazards and secondly with regards to broader socio-economic issues. Bristol has suffered from significant flooding in the past, with the floating harbour and low-lying city centre being identified as key areas vulnerable to tidal, fluvial and groundwater flooding. The flood of 1968 was one of the most significant and damaging flooding events in the city, caused by both surface water and fluvial flooding that resulted in high damages and impacts to the city and its inhabitants. The construction of large interceptor tunnels in response to this, to divert exceedance flows higher up in the catchment, reduced fluvial flood risk in the city. In 2012, significant flooding occurred across most of the UK due to some of the highest rainfall events since record collection began. During this time, the most notable single flood event lasted two days, with 30 houses internally flooded and many more suffering flooding of gardens, garages and driveways. In order to better manage flood risks in Bristol area, a 'Local Flood Risk Management Strategy' was produced and released in early 2018. The Strategy sets out the Bristol City Council vision for managing flood risk in the city, together with other organisations that have a role in flood-risk management [29]. Bristol City Council has already developed an intensive work towards resilience, and it is proactively committed to increase Bristol's resilience: from social cohesion

to economic stresses and by enhancing resilience to all sources of flooding. The resilience of the city to climate change (CC) can be highly related to its urban services' resilience, their interdependencies and cascade effects. For Bristol, the resilience assessment was undertaken for the flooding hazard related to rainfall and sea level variables, by its importance regarding Bristol resilience to CC.

**Figure 3.** Bristol resilience assessment results for flooding: (**a**) Overall assessment, (**b**) overall assessment per dimension, (**c**) assessment of the objective autonomous electrical energy service, (**d**) assessment of the criterion water service preparedness for disaster response.


*Article* **Influence of Wave Climate on Intra and Inter-Annual Nearshore Bar Dynamics for a Sandy Beach**

**Nataliya Andreeva 1,\*, Yana Saprykina 2, Nikolay Valchev 1, Petya Eftimova 1 and Sergey Kuznetsov 2**

**Abstract:** The study investigates cross-shore outer sand bar dynamics in an open-coast non-tidal beach at the Bulgarian Black Sea due to wave climate. On seasonal to short-term (1–2 years) time scale, monthly field measurements of the outer bar profiles were related to respective modeled nearshore wave data. Hereby, seaward-shoreward bar migration was examined depending on the wave forcing, wave non-linearity, wave transformation scenarios, storms and direction of wave incidence. Analysis revealed that intra-annually highly non-linear waves were responsible for outer bar displacement, while the direction of migration depended on wave period, duration of conditions with wave steepness >0.04, angle of approach and total duration of storms. Short-term bar evolution was mainly governed by wave height and storms' parameters as the angle of approach and duration. The correlation between the outer bar location and wave height annual variations initiated the first for the explored Black Sea region examination of possible connection between wave height's temporal fluctuations and the variability of climatic indices the North Atlantic Oscillation (NAO), the Atlantic Multi-decadal Oscillation (AMO), the East Atlantic Oscillation (EA), the Arctic Oscillation (AO), the East Atlantic-Western Russia (EA/WR) and the Scandinavian (SCAND) patterns. According to the results the inter-annual outer bar location may vary depending on periods of maximum annual wave fluctuations, which in turn predominantly depend on indices the EA (4–5, 10–11, 20–30 years), the EA/WR (2–4, 9–13 years) and the NAO (15 years).

**Keywords:** wave climate; nearshore bars; field data; cross-shore bar migration; wave conditions; wave non-linearity; storms; teleconnection patterns; Black Sea


Further original research is needed even more for the application of the OIST in the assessment of the economic success of Baltic restorations, where estimates are available only for the Estonian GDP for the bulk of the occupation period (since 1950). No estimates (not even tentative ones) are available in the SNA framework for Soviet Estonia or Lithuania before 1973. Therefore, for these countries, I was only able to provide an assessment of the early economic restoration success, using MPD data on the GDP of the Baltic countries since 1973. I also could specify the target values for the ultimate application of the OIST in 2039–2040, based on our estimates of GDPpc of these countries in 1938 and MPD data for 1989–1990. Pending progress in the measurement of real output in 1939–1972, the application of the OIST for assessing the actual performance success of these countries is not possible.

Although it was possible to fill the lacuna in the available knowledge on life expectancy for interwar Lithuania, there is no reliable information for the 1935–1958 period, which is needed for a more precise dating of the end of epidemiological transition in Lithuania and monitoring of the actual health performance success during the two decades remaining until the ultimate application of the OIST in 2039–2040. Another important improvement would be the enlargement of the available (thanks to Katus' research) collection of life tables for Estonia and Latvia with those on the 1939–1949 period. One possibility for how to narrow the gap for the 1940s would be the use of the still incompletely processed or published data of censuses under the German occupation in 1941–1943.4

Archive files containing anthropometric data on draftees to the Lithuanian military in 1929–1939 remains as a resource that is completely untapped by historical anthropometric research. The same applies for data on conscripts to the Soviet Army in all three countries, which were not accessible to biological anthropologists during the Soviet years and remain unexamined by contemporary Baltic historians.

The above remarks all refer to tasks and challenges of further improvement to the fundamental data needed for cross-time and cross-country comparative analysis of

4 For more details on the 1941 census in Estonia (called the "registration of the population"), see Maiste and Berendsen 2017; Maiste and Puur 2018.

the economic, health and somatic progress in the Baltic countries since their emergence as independent states in 1918. However, the agenda of comparative historical sociology of restorations is by no means exhausted by socio-economic issues alone. In Marxist parlance, the establishment of independent Baltic States was also a "bourgeois" revolution, involving the abolition of the division of the population into estates, radical land reform and establishment of democratic republics. However, the first attempt at the democratisation of the Baltic countries failed even before the Soviet occupation, with authoritarian coups destroying democracy in its fledgling stages in Lithuania in 1926, and in Latvia and Estonia in 1934.

By 1990, the population of Lithuania included only 11.70 percent born in 1926 or earlier, 5.19 percent who were at least 10 years old and 3.01 percent who were at least 15 years old in 1926 (HMD 2022). Therefore, no token restoration of democracy was socio-demographically possible in this country in 1990. On the other hand, type restored Lithuanian democracy could celebrate its endurance success already in 1996, narrowly escaping the early failure in September 1993, when the revolt of the servicemen of the Voluntary National Defence Service (VNDS; Savanoriška Krašto Apsaugos Tarnyba; SKAT) broke out. The core of the VNDS consisted of volunteers who, during the dramatic time of the confrontation between the government structures of the Republic of Lithuania and the Soviet military (in 1990–1991), were preparing themselves for armed resistance if Moscow's authorities were to attempt to bring down Lithuanian independence by force (Norkus 2012: 306–307).

These volunteers were enormously disappointed by the ex-communist Lithuanian Democratic Labour Party's victory in parliamentary elections in October 1992. The revolt diminished when the volunteers found no partners among the eminent political figures of the Lithuanian Right, who would agree to assume authority in the state after a coup. Had they behaved differently, post-communist political developments in Lithuania would have likely followed the trajectory of Georgia, where postcommunist democracy endured for an even shorter time (October 1990–September 1991) than its first experience in February 1919–March 1921. In September 1991, violent hostilities among pro-independence forces themselves erupted, culminating in an armed coup d'etat against the democratically elected President of Georgia Zviad Gamsakhurdia in late December 1991, followed by a civil war (Jones 2014).

Longer experiences with political democracy under interwar independence in Estonia and Latvia did indeed contribute to the stability of post-communist democracy in Estonia and Latvia, making possible the very token restoration of parliamentary democracy in both countries, which was implemented in the most impressive way in Latvia by the reenactment of its 1922 Constitution. Both restored democracies could celebrate their partial endurance success in 2004–2005, when they outlasted the original interwar democratic regimes. When setting exact dates, which are necessary for celebrating anniversaries, we should consider that in all three countries, the first democratic periods started with elections to constituent assemblies (see Nohlen and Stöver 2010). In Estonia, this kind of election took place already on 5–7 April 1919, and in Latvia they were held almost simultaneously with the Lithuanian elections (on April 17–18, 1920). The second democracy period commenced with democratic elections to the Supreme Soviets in February–March 1990, which went on to restore independence.

To recall (see Chap. 5), in 1988–1991, supporters of independence restoration were divided as to whether restoration of independence by the Supreme Soviets of the Baltic Soviet republics, elected according to the legislation of the occupier power (USSR), was in fact legally correct. According to present consensus among Baltic legal scholars and political scientists, the democratic legitimacy of the last Soviet parliaments provides legal and meta-juridical validity for their claims of identity between the interwar and post-communist states (Jundzis 2017; Mälksoo 2003; Ziemele 2005; Žalimas 1997, 2005). As a matter of principle, democratisation may precede the establishment or restoration of an independent state, as this was the case in the former Soviet and Yugoslavian republics.

To enable assessment of the performance success of democracy restoration in future research, continuing, expanding and complementing the analysis provided in this book, I would suggest using this version of the criterion of democracy restoration performance success:

#### CDRPS (Criterion of democracy restoration performance success): Restored democracy is performance successful if the values of deliberative, egalitarian, electoral, liberal and participatory democracy indexes under restored democracy surpass those of the original democratic regime.

This criterion is tailored to apply to data in the Varieties of Democracy (V-Dem) data sets, released by the V-Dem Institute based at the University of Gothenburg, Sweden. Its recent release (Coppedge et al. 2022) covers 202 countries for the years 1789–2021 and comprises of more than 483 V-Dem indicators, 82 indices and five high-level indices. I would like to suggest prospective researchers accept the complex and sophisticated conceptualisation of democracy devised by the constructors of these databases.

Assessment of the endurance success of a restored democracy can be made by comparing the duration of the restored democratic system with the duration of both the original democratic and intermediate non-democratic systems. Thus, the complete endurance success of democracy restoration in Lithuania can only be celebrated in 2054, when/if restored democracy will have also outlasted the complete period under authoritarian and totalitarian regimes (1926–1990). In Estonia and Latvia, it may take somewhat less to wait until the proper time (2046) for completion of the OIST test for the endurance success period.

However, an assessment of the performance success of the restored democratic regime makes sense only when comparing the original democratic and restored democratic regimes because the aims of democratic and authoritarian regimes are totally different. If there are dimensions where the democracy index value(s) under the original regime are higher than under the restored democratic regime, then the restoration democracy was only partially performance successful. If in all dimensions the original democratic regime surpasses the restored regime, then the restored democratic regime should be considered a performance failure. Exploration of V-Dem data on the Baltic countries suggests that generally values of Deliberative, Egalitarian, Electoral, Liberal and Participatory Democracy Indexes are higher for the restoration period than for the interwar years. However, examination of this task demands a separate study incorporating other sources of information as well.

Importantly, the monitoring of the condition of restored democracies using the highest interwar time values as benchmarks can also be continued after 2004–2005 until the point when their endurance success will have been completely proven. This is another service that better knowledge of our historical past and its actualisation in the historical sociology of restorations can provide for the enhancement of the restored Baltic democracies.

Threats to the stability of restored social systems can come from inside, deriving from the weakness of their economic bases (e.g. due to dependence on the export of a limited range of products) or outside (e.g. due to a geopolitically exposed location). The existence of these threats makes an assessment of the success of their restoration based only on their well-being performance incomplete. The situation of even very wealthy countries with high levels of human development may be precarious if they are not internationally secure.

Therefore, application of the restoration sociology approach includes an assessment of the international security of restored states. As far as international security is considered a collective good that cannot be created by a single state (especially by a small state, as exemplified by the Baltic States), this assessment is conducted using cross-time comparisons of configurations of the international order that provide this common good (or not):

#### CRIOPS (Criterion of the rehabilitation of international order performance success): A rehabilitated or restored configuration of international order C is performance successful if it is more peaceful and secure for member states than intermediate configuration B or original configuration A.

Wars between major powers or their dissolution mean the breakdown of a complete configuration, which is replaced by the next configuration featuring different major players. Applying the CRES, the duration of general peace under subsequent configurations of international order is compared, while the application of the CRIOPS involves counting local wars and the capacity of that particular configuration to avoid their upgrading to a general war. The application of this criterion is possible only as a separate study, encompassing all post-communist countries as part of the global international system.5

In this book, I limit myself only to a few considerations that are necessary for its completion. In fact, the political cultures of the restored Baltic States continue to be shaped by the trauma of their loss of independence in 1940, accompanied by the decimation of their most socially active members by Soviet repressions already in 1940–1941. Others escaped this fate by fleeing to the West in 1944, and those remaining were able to preserve their social position only by collaborating with the

5 For some preparatory work, see Norkus (2023, Chap. 2.3).

Soviet occupants. This trauma explains why determination to prevent a repetition of 1940 is the main driving force behind foreign policy of the restored Baltic States.

This determination includes the resolution to not repeat what is perceived as a key mistake of foreign policy during interwar independence. Specifically, this is capitulation to Soviet ultimatums to accept Soviet military bases in September–October 1939, when military resistance was still possible. Finland's successful resistance during the Winter War in 1939–1940 is perceived as proper behaviour, which the Baltic States sadly did not display in 1939–1940. Thus, the defence policies of the restored Baltic States are aimed at preparing them to repeat Finland's feat in the Winter War.

Different from the interwar years, the elites of the restored Baltic States securitize (perceive as a potential aggressor) only one state, which is the same for all three: the Russian Federation. They perceive post-communist Russia as another avatar of the Russian Empire, which is recognised as a perennial existential threat. The security situation was much more differentiated during the first independence period. Interwar Estonia elite's perceptions of territorial security threats display most similarities to those of its contemporary successors in terms of their overwhelming concern with the Soviet/Russian threat. The military of interwar Latvia had war plans with two potential adversaries – Soviet Russia and Germany, based on scenarios of Soviet or German invasions. Concerns about the "German threat" increased after Adolf Hitler's rise to power in 1933, almost overshadowing concerns about the "Soviet threat" (Ilmjärv 2004).

However, interwar Lithuania's international situation was the most complicated – and the most different from that of restored Lithuania. Lithuania was the only Baltic State without a border with the USSR, which was perceived by Lithuanian political elites more like an uncertain ally than a definite threat. The proclaimed top aim of Lithuania's foreign policy until 1938, when its government yielded to Poland's ultimatum to establish diplomatic relations, was to regain its historical capital Vilnius. According to all three of Lithuania's interwar constitutions (1922, 1928, 1938), Vilnius was the official capital of the Lithuanian state. Thus, in interwar Europe, Lithuania was a revisionist power together with the USSR, Germany, Hungary and Bulgaria (Butkus 2019; Kasparavičius 1996).

The reclaiming of Vilnius was possible only after Poland's military defeat in a new major war, where its most probable adversaries (and Lithuanian allies) were Germany and the USSR. Lithuanian military planners even acquiesced with military defeat and temporary occupation of a majority or even all of Lithuanian territory, with remainders of its military retreating to Latvia and its government going into exile. They took inspiration from the post-World War I restoration of Belgium and Serbia. Serbia did become Yugoslavia, perceived as Greater Serbia by Serbian nationalists, after suffering military defeat and occupation. It did ultimately win by taking the side of the victorious coalition (Jokubauskas 2014, 2019).

In the early 1930s, Lithuania's international position was further weakened by the conflict with Germany over Lithuania's attempts to Lithuanianise the autonomous Klaipėda Region. It did face resistance from the local government dominated by Germans and the bulk of the local population, including people of ethnically Lithuanian descent.6 Germany reacted by imposing economic sanctions on Lithuania. This conflict escalated after Hitler's rise to power, with economic sanctions almost turning into a complete economic blockade, which greatly aggravated the impact of the worldwide economic crisis and delayed recovery until 1936. Lithuanian hopes of regaining Vilnius collapsed after the USSR and Germany signed (in 1932 and 1934 respectively) non-aggression pacts with Poland (Eidintas et al. 2003).

This made possible the signing of the Treaty of Good Understanding and Co-operation between Lithuania, Latvia and Estonia on 12 September 1934 in Geneva, known as the Baltic Entente. However, it never developed into a military alliance, including at the very least the preparation of common war plans, and was not expanded by a custom tax union or other forms of economic cooperation. Lithuania did not receive any support from its Baltic allies after receiving the Polish ultimatum regarding Vilnius in March 1938, followed by the German ultimatum in March 1939 to cede the Klaipėda Region. Deepening of Baltic cooperation by pursuing a common defence policy was also hampered by their declaration of neutral powers status on the eve of World War II, which included waiving commitments to participate in the sanctions against the aggressor powers, which they did have as members of the League of Nations (Kasparavičius 2010, 2021).

Therefore, when it received the first Soviet ultimatum to accept Soviet troops on its territory in late September 1939, the Estonian government did not even attempt to consult its allies, while the other Baltic governments behaved similarly both in the autumn of 1939 and in June 1940, silently capitulating (Ilmjärv 2004) one after another. Certainly, acceptance of the Baltic countries to NATO in 2004 (together with admission to the EU in the same year) radically improved the international security situation of the restored Baltic countries compared to their position in the interwar "Versailles system", which in hindsight proved to be so fragile.

However, the outbreak of the Russian-Ukrainian war in 2014 disclosed that NATO membership does not bring total security. Its escalation in 2022 from a "hybrid war" to open military conflict further increased the risk that their territories will become a theatre of war between Russia and the (hopefully) ultimately victorious NATO forces. While this is broadly expected in the Baltic countries, the realisation of this expectation can only meaningfully described as a shock.

The meaning of shock expresses the connotation of surprise. This does not mean that a shock event is completely unexpected, although some are (the Covid-19 pandemic is an example). Earthquakes are expected in seismic zones. Before the post-Napoleonic restoration era, wars between European great states were the norm, while recurring economic crises are part of the normalcy of capitalism. The surprise element of shock refers to the unpredictability of the timing and extent of the next occurrence of the disturbance, which is expected to happen.

6 Speaking Lithuanian, it had religious (Protestant) identity, different from Catholic Major Lithuania.

The prospect of an upcoming Russian-NATO war on the territory of the Baltic States provides relevance for further research in the framework of the comparative historical sociology of restorations, guided by the Criterion of restoration resilience, imported and adapted from the field of restoration ecology (see Chap. 3).

#### CRR (Criterion of restoration resilience): A successfully restored social system is more resilient in comparison with the original system both in the sense of its capacity for rapid recovery after shocks and its lesser vulnerability to systemic change, shifting it into an alternative equilibrium. 7

Systems with weak resilience need a longer time to recover and may shift into an alternative equilibrium, which implies systemic change. So CRR combines two ideas of resilience: resilience as the return speed to the initial state of equilibrium state and as the degree of (in)vulnerability to transition to an alternative stable state. Alternative stable states are defined by their stable states or attractors, which may differ in terms of the depth and breadth of their attraction basins (see Holling 1973; Scheffer 2009).

The measurement of resilience by the speed of return to the initial equilibrium expresses an engineering-based concept of resilience. It makes sense to apply the idea of return time to both ecological and social systems, as they may be significantly different by the time it takes them to recover from disturbances such as fire for forests, cities from natural catastrophes (e.g. floods or earthquakes) and economies from wars or economic crises. In the restoration sociology of the Baltic countries, this idea of resilience can be fruitfully applied when comparing the impact of the Great Depression of 1929–1933 and of the Great Recession of 2008–2011 on the Baltic economies.

Using the CRR to explore the impact of a possible or upcoming NATO-Russian war on the restored Baltic States, both ideas of resilience are highly relevant. The alternative equilibrium in such a war is just the extinction or dispersion of the actual populations of these countries, making their territories vacant (albeit radiationcontaminated) colonisation areas. So, when applying the CRR to the situation of an upcoming war, we would ask the following questions: are the populations of the contemporary Baltic States better protected from war-related extinction in comparison with those of the interwar Baltic States? What can be done to increase the prospects of their survival as well as to increase the speed of return to normalcy provided that war will not end with transition to an alternative equilibrium?

Obviously, these questions are so topical and complicated that they can be answered only by conducting multidisciplinary research projects, involving the collaboration of experts from different countries. So, I close with a few remarks focusing on two critical areas: food security and energy security. In both cases, I highlight the possible contribution of historical sociology of restorations.

7 For more details, see Norkus 2023. In this book, CRR will be applied only in the Concluding Discussion.

The scenario of a temporary new occupation of the Baltic countries in the event of military conflict with Russia is tacitly assumed in the official documents of the Baltic States outlining their national security strategy priorities. The Lithuanian document commits 'all and each citizen to resist the aggressor by all possible means, including military defence, partisan war, civic disobedience, refusal to cooperate with the occupation administration and other means'. 8 The success of a partisan war and civic disobedience is critically dependent on the capacity of the civil population to survive without having to cooperate with the occupant administration, which predictably will not care about its survival. Quite the opposite, genocidal policies can be expected as a response to partisan war and civic disobedience.

The predominantly agrarian character of the Baltic economies, low levels of urbanisation and comparatively high levels of agricultural productivity enabled the Baltic countries to survive the World War II years without succumbing to famine, which is what happened in many countries or parts of their territories under German occupation (Collingham 2012). In 1946–1947, Ukraine, Moldova and parts of central Russia were hit by famine caused by drought, preceding war devastation and exacerbated by the policies of the Soviet government (Ganson 2009). However, the Baltic republics were not affected – because of afore-mentioned reasons and because collectivisation had still not been implemented at this time. With no sufficient food resilience resembling that which the Baltic countries displayed under military occupations during WWII, there is a risk that their exile governments may return to countries liberated from the Russian aggressor devoid of a population, previously starved out by the occupant administration.

This problem is also important in the scenario where the Russian military will not be able to swiftly occupy the Baltic States and they will become an area of protracted military standoff where decisive battles will take place. During the period of WWI and subsequent independence wars, among the Baltic countries Latvia turned out to be the least food-resilient, with part of its urban population starving to death in 1918–1919 (Šilde 1976: 295). This was the price for Latvia's relative modernity by 1914. As the most urbanised and industrialised Baltic country, it was the least food self-sufficient and so, the least food-resilient (Norkus and Markevičiūtė 2021). However, the main reason was that Latvia was where positional warfare continued for more than2 years, devastating a larger part of its territory (see Chap. 8).

As far as the contemporary Baltic States are thoroughly urbanised and only a fraction of their populations is employed in agriculture, the food resilience of the restored Baltic countries is even lower than in Latvia by 1914. This applies both in the sense of capability to feed their populations after food imports and inputs (fuel, fertilisers) necessary to continue agricultural production under occupation (resilience against the shift to an alternative equilibrium) have ceased and the ability of agricultural production to swiftly recover after liberation from Russian occupation

8 Lietuvos Respublikos Seimas. Nutarimas dėl nacionalinio saugumo strategijos patvirtinimo 2002 m. gegužės 28 d. Nr. IX-907 Vilnius https://e-seimas.lrs.lt/portal/legalAct/lt/TAD/TAIS.1 67925?jfwid=nz8qn8f5i. Accessed 10 January 2023.

(resilience as recovery speed). Food resilience is maximised by increasing the food self-sufficiency of a country. By 1939, all three Baltic countries were net food exporters and thus self-sufficient to a high degree, meaning they also displayed high food resilience (Norkus and Markevičiūtė 2021: 655–657). The comparative study of food resilience of the interwar and restored Baltic countries would be a highly policy-relevant contribution of the historical sociology of restoration furthering the enhancement of their security.

The capability of the civil population to survive at least one winter under hostile foreign occupation should be considered as the crucial test of the energetic resilience in the sense of (in)vulnerability to the transition to an alternative equilibrium. Maximal levels of security against energy supply shocks are ensured by energy supply self-sufficiency. Most premodern agrarian societies did achieve such selfsufficiency due to low levels of energy consumption. Their energy needs could be satisfied using only local resources of wood, wind, water and animal power energy.

Only industrial and post-industrial countries with large endowments of fossil fuels or uranium are able to satisfy their energy needs without having to rely on energy imports, which make them vulnerable to interruptions in energy supply or energy price fluctuations. Among the interwar Baltic countries, Estonia was a completely energy self-sufficient country due to its development of a shale oil industry (in fact, in 1939 it even exported motor fuel). Although it did import some coal and oil products for economic reasons, as a matter of principle, interwar Estonia could satisfy domestic energy demands by its own production, substituting coal with oil shale or shale oil (Holmberg 2008).

This did not apply to the other Baltic countries. The interruption of coal imports stopped the bulk of Riga's industry both in 1914 and in 1939–1940 (Stranga 2015: 209–220). Nevertheless, the populations of the Baltic countries (except for their Jewish parts, which became the victims of the Holocaust) could survive 3 years of German occupation in 1941–1944 even in the absence of fuel imports (except for what was needed for the German army). Agricultural production could continue using animal draught force, while biomass (woods) was substituted for coal for household heating needs and partly also for those of industry. This is barely imaginable for their modern economies, where not only industry but also agricultural production is no longer possible without fuel imports and a stable electricity supply.

While the governments of the Baltic States do not display awareness of any food security risks, this is not the case for their energy security needs. However, they do not perceive as a risk the low energy self-sufficiency of the Baltic countries, but rather their dependence on a sole supplier – Russia, which is also perceived as sole probable aggressor. According to this perception, so long as the Baltic States remain dependent on Russia as their energy supplier, the former metropolis power does not need to use military power to enforce its will – it can do this simply by halting deliveries of gas and electricity. The leverage of energy supply was demonstrated by the partial success of the economic blockade of Lithuania from 18 April to 1 July 1990, when Moscow forced Lithuania to conditionally suspend its independence declaration act (Antanaitis 2001; Šimėnas 1996; Vagnorius 2010).

Escalation of the Ukrainian war from its "hybrid war" phase into full-scale military conflict in 2022 prompted the Baltic countries to stop their energy imports from Russia. This was made possible by EU-supported investments into the build-up of infrastructure. It includes the construction already in 1995–1999 of the Būtingė oil terminal to secure an alternative crude oil delivery route to the Lithuanian Mažeikiai oil refinery, which remains the main supplier of liquid fuels for markets of all three Baltic countries; installation of two submarine power cables (Estlink-1 and Estlink-2), connecting the power grids of Estonia and Finland in 2005–2006 and 2012–2014; completion of the gas pipeline from Poland to Lithuania in 2021, and many other projects (Leonavičius and Genys 2017).

However, this did not bring Latvia and Lithuania to the energy resilience levels of the interwar years, and even that of Estonia may diminish due to the decreasing contribution of its oil shale industry to the overall energy supply. Diversification of energy import sources will not diminish dependence on energy imports as such, while energy self-sufficiency alone amounts to complete energy resilience. Even during a brief occupation and its rollback by allied NATO forces, the populations of the Baltic countries may freeze if military action were to take place in the winter. The reconstruction of Soviet-era residential buildings to improve their energy conservation properties did help to increase the resilience of most dwellings to brief interruptions in heating during winter, but would be insufficient in the event of longer interruptions to the supply of electricity and heating.

Importantly, a centralised energy supply structure is highly vulnerable not only to military attacks (this is one of the painful lessons of the Russian-Ukrainian war), but also to technogenic accidents, which can not only interrupt energy supply, but also cause environmental pollution as a side effect. Therefore, the greening of energetics is the most promising avenue to bring the energy resilience of the Baltic countries back to interwar levels, when the bulk of their energy needs were satisfied by biofuels (mainly firewood).

Of course, this does not mean just a restoration of the energy balance of the interwar years because along with the renewable energy sources (biomass) used in this time, the use of wind and solar energy should also be increased, based on wind turbines and solar cell technologies that did not exist in the past. The equipment of individual houses with solar cell batteries may decrease the dependence of many energy users on a centralised supply source. In this way, a large part of the Baltic population can become enabled to switch from being energy consumers to prosumers, satisfying their energy needs through local production for their own needs. Food resilience may be increased along similar lines by encouraging the urban population to use their rural residences (now used only for recreation purposes) for food production (Alber and Kohler 2008; Smith and Jehlička 2013; Steel 2020). Owned by many Baltic urbanites, they could also serve as safe retreats in cases of emergency.

These are only a few illustrations of how comparative historical sociological research can inform public policy choices in the restored Baltic States, in addition to offering a better understanding of the Baltic past. Far from exhausting the agenda of research on social change in the Baltic countries during the recent century within this framework, this book is (hopefully) only a pioneering exploration of the heuristic potential of this approach. I also hope that it stimulates quantitative social science history research into the complicated history of the Baltic countries during the past century, so as to fill the remaining lacunas and improve the results exposed in this book.

#### References

———. 2019. Netiesioginis poveikis ir Lietuvos karinis saugumas 1919–1940 m. Klaipėda: Druka.

———. 2005. Lietuvos Respublikos nepriklausomybės atkūrimo 1990 m. kovo 11 d. tarptautiniai teisiniai pagrindai ir pasekmės. Vilnius: Demokratinės Politikos Institutas.

Open Access This chapter is licensed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

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## Supplement: Life Expectancy in the Interwar Baltic Countries

Estonia, 1922–1938 (Tables S1 and S2)

Supplement: Life Expectancy in the Interwar Baltic Countries 289

Lithuania, 1925–1934 (Tables S5 and S6)

Author's own calculations, improved by Domantas Jasilionis. Norkus et al. (2022)

Table S6 Lithuanian males, life expectancy in 1925–1934

Author's own calculations, improved by Domantas Jasilionis. See also Norkus et al. (2022)

## References


**Glossary**

**2. Specifics of thermophysical properties of SCFs**

*Advanced Supercritical Fluids Technologies*

**No. Literature source**

1 Pioro et al. [19]

3 Mann and Pioro [20]

4 Gupta et al. [21]

5 Pioro and Mokry [22]

6 Pioro and Duffey [9]

*reduced-pressure scaling: P*

*Pcr*

*Fluid* ¼ *P Pcr SCW.*

*\**

**6**

**Table 4.**

Prior to a general discussion on specifics of forced-convective heat transfer at critical and supercritical pressures, it is important to define special terms and expressions used at these conditions [6, 9]. For a better understanding of these

> Properties of selected metals, alloys, and diamond Properties of selected insulating materials Radiative properties of selected materials Properties of selected nuclear fuels

Properties of selected gases at atmospheric pressure

Thermophysical properties of nuclear-reactor coolants 2 Handbook [6] H2O, CO2, He ‑ ‑ *T*-*s* diagrams

H2O (SCW) *P*cr, 25, 30, 35,

CO2 (SC CO2) *P*cr, 8.4, 10.0,

FLiNaK (MSR) 0.1 H2O/SCW (PWR/SCWR) 15.5/25 He (VHTR, GFR) 7, 9 Na, Pb, Pb-Bi (SFR, LFR) 0.1

SC R-134a *P*cr, 5, 10, 13,

He *P*cr and other

40

11.7

pressures

15

25.0 8.4\* 4.6\*

*Pressures for SC carbon dioxide, R-134a, and R-12 are equivalent for SCW pressure of 25 MPa, based on, so-called,*

*Selected list of literature sources on thermophysical properties of fluids, gases, and other materials.*

CO2 (AGR) 4 250‑1000 *ρ*, *k*, *μ*, *c*p, *H*, **Pr**, *β*

H2O ‑ ‑ *T*-*s* diagram H2O (SCW) *P*cr, 25, 30, 35 350‑600 *ρ*, *k*, *μ*, *ν*, *c*p, *H*, **Pr**, *β* R-12 (SC R-12) *P*cr, 4.65 0‑350 *ρ*, *k*, *μ*, *ν*, *c*p, *H*, **Pr**, *β*

R-134a (SC R-134a) *P*cr, 4.6 70‑150 *ρ*, *k*, *μ*, *ν*, *c*p, *H*, **Pr**, *β*

Properties of selected cryogenic gases Properties of selected fluids on saturation line Properties of selected supercritical fluids Properties of selected liquid alkali metals

H2O (BWR, PHWR, PWR)

Air, Ar, CO2, He, H2, Kr (gases)

SCW SC CO2 SC R-134a (three fluids on same graph)

**Fluid** *P***, MPa** *T***, °C Properties**

7, 11, 15 50‑375 *ρ*, *k*, *μ*, *ν*, *c*p, *H*, **Pr**, *β*

350‑600 *ρ*, *k*, *μ*, *ν*, *c*p, *H*, **Pr**, *β*

0‑165 *ρ*, *k*, *μ*, *ν*, *c*p, *H*, **Pr**, *β*

Range of *T k*, *c*p, *β*

‑100‑175 *k*, *c*p, *β*

*ρ*, *k*, *μ*, *c*p, *H*, **Pr**

ð Þ 0*:*5 � 1*:*6 *T Tcr*

0.1 0‑1000 *ρ*, *k*, *μ*, *c*p, **Pr**, *β*

*Compressed fluid* is the fluid at a pressure above the critical pressure, but at a temperature below the critical temperature (see **Figure 10**).

*Critical point (also called a critical state)* is the point in which the distinction between the liquid and gas (or vapor) phases disappears (see **Figure 10**), that is, both phases have the same temperature, pressure, and specific volume or density. The critical point is characterized with the phase-state parameters: *T*cr, *P*cr and *v*cr (or *ρ*cr), which have unique values for each pure substance.

*Deteriorated heat transfer (DHT)* is characterized with lower values of the HTC compared to those for normal heat transfer (NHT); and hence, has higher values of wall temperature within some part of a heated channel (see **Figures 12, 13a, 24b, 25b, 27, 31**, and **35**) or within the entire heated length (see **Figure 14b**).

*Improved heat transfer (IHT)* is characterized with higher values of the HTC compared to those for NHT; and hence, lower values of wall temperature within some part of a heated channel (see **Figures 12, 21, 25, 27b, 33**, and **34**) or within the entire heated length. In our opinion, the IHT regime or mode includes peaks or "humps" in the HTC profile near the critical or pseudocritical points.

*Normal heat transfer (NHT)* can be characterized in general with HTCs similar to those of subcritical convective heat transfer far from the critical or pseudocritical regions, when they are calculated according to the conventional single-phase Dittus-Boelter-type correlations: **Nu** = 0.0243 **Re**0.8**Pr**0.4 (see **Figures 12, 13a, 14a, 21, 24, 25, 27**, and **30**–**34**).

*Overheated vapor* is the vapor at pressures below the critical pressure, and at temperatures above the saturation temperature, but below the critical temperature (see **Figure 10**).

*Pseudocritical line* is the line, which consists of pseudocritical points (see **Figure 10**).

*Pseudo-boiling* is a physical phenomenon similar to subcritical-pressure nucleate boiling, which may appear at SCPs. Due to heating of an SCF with a bulk-fluid temperature below the pseudocritical temperature (high-density fluid, i.e., "liquidlike") (see **Figures 10, 11, 13b** and **15**), some layers near the heated surface may attain temperatures above the pseudocritical temperature (low-density fluid, i.e., "gas-like"). This low-density "gas-like" fluid leaves the heated surface in a form of variable density volumes (bubbles). During the pseudo-boiling, the HTC usually increases (IHT regime).

*Pseudocritical point* (characterized with *P* and *Tpc*) is the point at a pressure above the critical pressure and at a temperature (*Tpc* > *Tcr*) corresponding to the maximum value of specific heat at this particular pressure (see **Figures 10, 11**, and **13b**).

*Pseudo-film boiling* is a physical phenomenon similar to subcritical-pressure film boiling, which may appear at SCPs. At pseudo-film boiling, a low-density fluid (a fluid at temperatures above the pseudocritical temperature, i.e., "gas-like") prevents a high-density fluid (a fluid at temperatures below the pseudocritical temperature, i.e., "liquid-like") from contacting ("rewetting") a heated surface. Pseudo-film boiling leads to the DHT regime.

*Supercritical fluid* is the fluid at pressures and temperatures that are higher than the critical pressure and critical temperature (see **Figure 10**). However, in the

present paper, the term *supercritical fluid* usually includes both terms—*supercritical fluid* and *compressed fluid*.

*Supercritical "steam"* is actually supercritical water, because at supercritical pressures fluid is considered as a single-phase substance (see **Figure 10**). However, this term is widely (and incorrectly) used in the literature in relation to supercritical-"steam" generators and turbines.

*Superheated steam* is the steam at pressures below the critical pressure, but at

*T-s diagram of generic subcritical-pressure Rankine steam-turbine power cycle (old coal-fired thermal power*

*Supercritical-Fluids Thermophysical Properties and Heat Transfer in Power-Engineering…*

*DOI: http://dx.doi.org/10.5772/intechopen.91474*

Also, profiles of the basic thermophysical properties (density, thermal conductivity, dynamic viscosity, specific heat and specific enthalpy) and Prandtl number for four SCFs: water, ethanol, methanol, and carbon dioxide; at critical and one supercritical pressure, which is 25 MPa for water and the corresponding to that equivalent pressures for all other SCFs vs. reduced temperature (temperature) are

**3. Specifics of forced-convection heat transfer at supercritical pressures**

Water is the most widely used coolant or working fluid at SCPs. The largest application of SCW is in SC "steam" generators and turbines, which are widely used in the thermal power industry worldwide. Currently, upper limits of pressures and temperatures used in the thermal-power industry are about 30–38 MPa and 600–625°C, respectively (see **Table 1**). A new direction in SCW application in the power industry has been the development of SCWR concepts (see **Table 2**), as part of the Generation-IV International Forum (GIF) [27] initiative (for details, see [6, 9–13, 28–30]; and Proceedings of the International Symposiums on SCWRs (ISSCWR) (selected augmented and revised papers from ISSCWRs have been published in the ASME Journal of Nuclear Engineering and Radiation Science in

Experiments at SCPs are very expensive and require sophisticated equipment and measuring techniques. Therefore, some of these studies (e.g., heat transfer in fuel-bundle simulators) are proprietary and, hence, usually are not published in

The majority of studies deal with heat transfer and hydraulic resistance of working fluids, mainly water, carbon dioxide, refrigerants, and helium, in circular bare tubes [9, 22, 31–34]. A limited number of studies were devoted to heat transfer

2020, Vol. 6 No. 3; in 2018, Vol. 4, No. 1, and 2016, Vol. 2, No. 1).

and pressure drop in annuli and bundles [9, 10, 35–45].

temperatures above the critical temperature (see **Figure 10**).

shown in **Figures 15–20**.

*plants and SFR NPPs) [6, 7].*

**Figure 3.**

**3.1 Vertical bare tubes**

open literature.

**9**

### **Figure 1.**

*T-s diagram of generic SCP Rankine "steam"-turbine power cycle (modern advanced coal-fired thermal power plants and future SCWR NPPs) [6, 7].*

**Figure 2.**

*T-s diagram of generic subcritical-pressure Rankine steam-turbine power cycle (older coal-fired thermal power plants and AGR Torness NPP) [6, 7].*

*Supercritical-Fluids Thermophysical Properties and Heat Transfer in Power-Engineering… DOI: http://dx.doi.org/10.5772/intechopen.91474*

### **Figure 3.**

present paper, the term *supercritical fluid* usually includes both terms—*supercritical*

*Supercritical "steam"* is actually supercritical water, because at supercritical pressures fluid is considered as a single-phase substance (see **Figure 10**). However, this term is widely (and incorrectly) used in the literature in relation to supercriti-

*T-s diagram of generic SCP Rankine "steam"-turbine power cycle (modern advanced coal-fired thermal power*

*T-s diagram of generic subcritical-pressure Rankine steam-turbine power cycle (older coal-fired thermal power*

*fluid* and *compressed fluid*.

**Figure 1.**

**Figure 2.**

**8**

*plants and AGR Torness NPP) [6, 7].*

*plants and future SCWR NPPs) [6, 7].*

cal-"steam" generators and turbines.

*Advanced Supercritical Fluids Technologies*

*T-s diagram of generic subcritical-pressure Rankine steam-turbine power cycle (old coal-fired thermal power plants and SFR NPPs) [6, 7].*

*Superheated steam* is the steam at pressures below the critical pressure, but at temperatures above the critical temperature (see **Figure 10**).

Also, profiles of the basic thermophysical properties (density, thermal conductivity, dynamic viscosity, specific heat and specific enthalpy) and Prandtl number for four SCFs: water, ethanol, methanol, and carbon dioxide; at critical and one supercritical pressure, which is 25 MPa for water and the corresponding to that equivalent pressures for all other SCFs vs. reduced temperature (temperature) are shown in **Figures 15–20**.

### **3. Specifics of forced-convection heat transfer at supercritical pressures**

### **3.1 Vertical bare tubes**

Water is the most widely used coolant or working fluid at SCPs. The largest application of SCW is in SC "steam" generators and turbines, which are widely used in the thermal power industry worldwide. Currently, upper limits of pressures and temperatures used in the thermal-power industry are about 30–38 MPa and 600–625°C, respectively (see **Table 1**). A new direction in SCW application in the power industry has been the development of SCWR concepts (see **Table 2**), as part of the Generation-IV International Forum (GIF) [27] initiative (for details, see [6, 9–13, 28–30]; and Proceedings of the International Symposiums on SCWRs (ISSCWR) (selected augmented and revised papers from ISSCWRs have been published in the ASME Journal of Nuclear Engineering and Radiation Science in 2020, Vol. 6 No. 3; in 2018, Vol. 4, No. 1, and 2016, Vol. 2, No. 1).

Experiments at SCPs are very expensive and require sophisticated equipment and measuring techniques. Therefore, some of these studies (e.g., heat transfer in fuel-bundle simulators) are proprietary and, hence, usually are not published in open literature.

The majority of studies deal with heat transfer and hydraulic resistance of working fluids, mainly water, carbon dioxide, refrigerants, and helium, in circular bare tubes [9, 22, 31–34]. A limited number of studies were devoted to heat transfer and pressure drop in annuli and bundles [9, 10, 35–45].

### **Figure 4.**

*T-s diagram of generic subcritical-pressure Rankine saturated-steam-turbine power cycle (PWR and BWR NPPs) [6, 7].*

New experiments in the 1990s–2000s were triggered by several reasons: (1) thermophysical properties of SCW have been updated from the 1950s–1970s, for example, a peak in thermal conductivity in the critical/pseudocritical points was "officially" introduced in the 1990s; (2) experimental techniques have been improved; (3) in SCWRs various bundle flow geometries will be used instead of bare-tube geometry; and (4) in SC "steam" generators of thermal power plants larger diameter tubes/pipes (20–40 mm) are used, however, in SCWRs hydraulic-

*T-s diagram for 600-MWth VHTR NPP with SC-CO2 (S-CO2) power cycle (based on* **Figure 5***) [18].*

*Supercritical-Fluids Thermophysical Properties and Heat Transfer in Power-Engineering…*

*DOI: http://dx.doi.org/10.5772/intechopen.91474*

Accounting that SCW, SC carbon dioxide and SC R-12 are the most widely used fluids, specifics of heat transfer, including generalized correlations, will be discussed in this paper. Specifics of heat transfer and pressure drop at other conditions and/or for other fluids are discussed in the book by Pioro and

All primary sources (i.e., all sources found by the authors from a total of 650 references dated mainly from 1950 till beginning of 2006) of heat transfer experimental data for water and carbon dioxide flowing inside circular tubes at supercrit-

In general, three major heat transfer regimes (for their definitions, see Section 2,

Glossary) can be noticed at critical and supercritical pressures (for details, see

equivalent diameters of proposed bundles will be within 5–12 mm.

ical pressures are listed in the book by Pioro and Duffey [9].

**Figures 12, 13a, 14, 21, 24, 25, 27, 30–35**):

Duffey [9].

**11**

**Figure 6.**

**Figure 5.** *Layout of 600-MWth VHTR NPP with SC-CO2 power cycle (based on figure from Bae et al. [17]) [18].*

*Supercritical-Fluids Thermophysical Properties and Heat Transfer in Power-Engineering… DOI: http://dx.doi.org/10.5772/intechopen.91474*

### **Figure 6.**

**Figure 4.**

**Figure 5.**

**10**

*NPPs) [6, 7].*

*Advanced Supercritical Fluids Technologies*

*T-s diagram of generic subcritical-pressure Rankine saturated-steam-turbine power cycle (PWR and BWR*

*Layout of 600-MWth VHTR NPP with SC-CO2 power cycle (based on figure from Bae et al. [17]) [18].*

*T-s diagram for 600-MWth VHTR NPP with SC-CO2 (S-CO2) power cycle (based on* **Figure 5***) [18].*

New experiments in the 1990s–2000s were triggered by several reasons: (1) thermophysical properties of SCW have been updated from the 1950s–1970s, for example, a peak in thermal conductivity in the critical/pseudocritical points was "officially" introduced in the 1990s; (2) experimental techniques have been improved; (3) in SCWRs various bundle flow geometries will be used instead of bare-tube geometry; and (4) in SC "steam" generators of thermal power plants larger diameter tubes/pipes (20–40 mm) are used, however, in SCWRs hydraulicequivalent diameters of proposed bundles will be within 5–12 mm.

Accounting that SCW, SC carbon dioxide and SC R-12 are the most widely used fluids, specifics of heat transfer, including generalized correlations, will be discussed in this paper. Specifics of heat transfer and pressure drop at other conditions and/or for other fluids are discussed in the book by Pioro and Duffey [9].

All primary sources (i.e., all sources found by the authors from a total of 650 references dated mainly from 1950 till beginning of 2006) of heat transfer experimental data for water and carbon dioxide flowing inside circular tubes at supercritical pressures are listed in the book by Pioro and Duffey [9].

In general, three major heat transfer regimes (for their definitions, see Section 2, Glossary) can be noticed at critical and supercritical pressures (for details, see **Figures 12, 13a, 14, 21, 24, 25, 27, 30–35**):

### **Figure 7.**

*Schematic of 600-MWth GFR concept considered initially by GIF with direct Brayton helium cycle (Courtesy of GIF) (see also [6]).*

### **Figure 8.**

*Layout of 2400-MWth GFR NPP with He-N2 indirect combined power cycle (based on figure from Anzieu [23]) [18].*

These heat transfer regimes and special phenomena appear to be due to significant variations of thermophysical properties near the critical and pseudocritical points

*Thermodynamics diagrams for water: (a) pressure-temperature and (b) temperature-specific entropy (based*

*T-s diagrams of 2400-MWth GFR NPP combined power cycle (based on* **Figure 8***) [18].*

*Supercritical-Fluids Thermophysical Properties and Heat Transfer in Power-Engineering…*

*DOI: http://dx.doi.org/10.5772/intechopen.91474*

Therefore, the following conditions can be distinguished at critical and SCPs:

a. Wall and bulk-fluid temperatures are below a pseudocritical temperature within a part of (see **Figure 12**) or the entire heated channel (see **Figures 14a,**

and due to operating conditions.

**24a,** and **30**);

**Figure 9.**

**Figure 10.**

**13**

*on NIST [25]).*

Also, two special phenomena (for their definitions, see Section 2, Glossary) may appear along a heated surface: (1) pseudo-boiling; and (2) pseudo-film boiling.

*Supercritical-Fluids Thermophysical Properties and Heat Transfer in Power-Engineering… DOI: http://dx.doi.org/10.5772/intechopen.91474*

**Figure 9.**

*T-s diagrams of 2400-MWth GFR NPP combined power cycle (based on* **Figure 8***) [18].*

### **Figure 10.**

*Thermodynamics diagrams for water: (a) pressure-temperature and (b) temperature-specific entropy (based on NIST [25]).*

These heat transfer regimes and special phenomena appear to be due to significant variations of thermophysical properties near the critical and pseudocritical points and due to operating conditions.

Therefore, the following conditions can be distinguished at critical and SCPs:

a. Wall and bulk-fluid temperatures are below a pseudocritical temperature within a part of (see **Figure 12**) or the entire heated channel (see **Figures 14a, 24a,** and **30**);

1.Normal heat transfer;

**Figure 7.**

**Figure 8.**

*[23]) [18].*

**12**

*GIF) (see also [6]).*

*Advanced Supercritical Fluids Technologies*

2. Improved heat transfer; and

3.Deteriorated heat transfer.

Also, two special phenomena (for their definitions, see Section 2, Glossary) may

*Schematic of 600-MWth GFR concept considered initially by GIF with direct Brayton helium cycle (Courtesy of*

appear along a heated surface: (1) pseudo-boiling; and (2) pseudo-film boiling.

*Layout of 2400-MWth GFR NPP with He-N2 indirect combined power cycle (based on figure from Anzieu*

**Figure 11.**

*Profiles of selected thermophysical properties (density, specific heat, thermal conductivity, and dynamic viscosity) vs. temperature for SCW at pressure of 24.0 MPa (based on NIST [25]).*

All these conditions can affect SC heat transfer.

**Figure 13b** shows bulk-fluid-temperature and thermophysical-properties (thermal conductivity, dynamic viscosity, specific heat, and Prandtl number) profiles along the heated length of a vertical bare circular tube (operating conditions in this figure correspond to those in **Figure 13a**).

Some researchers have suggested that variations in thermophysical properties near critical and pseudocritical points result in the maximum value of HTC. Thus, Yamagata et al. [46] found that for SCW flowing in vertical and horizontal tubes, the HTC increases significantly within the pseudocritical region (**Figure 21**). The magnitude of the peak in HTC decreases with increasing heat flux and pressure. The maximum HTC values correspond to a bulk-fluid enthalpy, which is slightly less than the pseudocritical bulk-fluid enthalpy.

**Figure 13.**

**15**

**Figure 12.**

*(a) Temperature and HTC profiles along heated length of vertical bare tube with upward flow of SCW (data by Kirillov et al. [26]): D = 10 mm; Lh = 4 m; points—experimental data; curves—calculated data. Uncertainties of primary parameters are listed in* **Table 5***; and (b) temperature and thermophysical-properties profiles along heated length of vertical tube: operating conditions in this figure correspond to those in (a); and thermophysical properties based on bulk-fluid temperature. Profiles of density, specific heat, thermal conductivity, and dynamic viscosity vs. temperature for SCW at pressure of 24.0 MPa are shown in* **Figure 11***.*

*Temperature and HTC profiles along heated length of vertical bare tube with upward flow of SCW (data by*

*Supercritical-Fluids Thermophysical Properties and Heat Transfer in Power-Engineering…*

*DOI: http://dx.doi.org/10.5772/intechopen.91474*

*curves—calculated data; curve for HTC is calculated through Dittus-Boelter correlation (Eq. (1)). Profiles of density, specific heat, thermal conductivity, and dynamic viscosity vs. temperature for SCW at pressure of 24.0 MPa are shown in* **Figure 11***. Uncertainties of primary parameters are listed in* **Table 5***.*

*s; points—experimental data;*

*Kirillov et al. [26]): D = 10 mm; Lh = 4 m; qdht = 316 kW/m2 at G = 503 kg/m2*

*Supercritical-Fluids Thermophysical Properties and Heat Transfer in Power-Engineering… DOI: http://dx.doi.org/10.5772/intechopen.91474*

### **Figure 12.**

b. Wall temperature is above, and bulk-fluid temperature is below a

*Profiles of selected thermophysical properties (density, specific heat, thermal conductivity, and dynamic*

c. Wall temperature and bulk-fluid temperature is above a pseudocritical temperature within a part of or the entire heated channel (see **Figures 12,**

or the entire heated channel (see **Figure 14b**);

*viscosity) vs. temperature for SCW at pressure of 24.0 MPa (based on NIST [25]).*

d. High heat fluxes (see **Figures 13a**, **24** and **25**);

e. Entrance region (see **Figures 12, 13a, 32,** and **34**);

h. Effect of gravitational forces at lower mass fluxes; etc.

All these conditions can affect SC heat transfer.

**13a, 21, 31**–**35**);

*Advanced Supercritical Fluids Technologies*

**Figure 11.**

**14**

f. Upward and downward flows;

figure correspond to those in **Figure 13a**).

than the pseudocritical bulk-fluid enthalpy.

g. Horizontal flows; and

pseudocritical temperature within a part of (see **Figures 13a, 31, 34,** and **35**)

**Figure 13b** shows bulk-fluid-temperature and thermophysical-properties (thermal conductivity, dynamic viscosity, specific heat, and Prandtl number) profiles along the heated length of a vertical bare circular tube (operating conditions in this

Some researchers have suggested that variations in thermophysical properties near critical and pseudocritical points result in the maximum value of HTC. Thus, Yamagata et al. [46] found that for SCW flowing in vertical and horizontal tubes, the HTC increases significantly within the pseudocritical region (**Figure 21**). The magnitude of the peak in HTC decreases with increasing heat flux and pressure. The maximum HTC values correspond to a bulk-fluid enthalpy, which is slightly less

*Temperature and HTC profiles along heated length of vertical bare tube with upward flow of SCW (data by Kirillov et al. [26]): D = 10 mm; Lh = 4 m; qdht = 316 kW/m2 at G = 503 kg/m2 s; points—experimental data; curves—calculated data; curve for HTC is calculated through Dittus-Boelter correlation (Eq. (1)). Profiles of density, specific heat, thermal conductivity, and dynamic viscosity vs. temperature for SCW at pressure of 24.0 MPa are shown in* **Figure 11***. Uncertainties of primary parameters are listed in* **Table 5***.*

### **Figure 13.**

*(a) Temperature and HTC profiles along heated length of vertical bare tube with upward flow of SCW (data by Kirillov et al. [26]): D = 10 mm; Lh = 4 m; points—experimental data; curves—calculated data. Uncertainties of primary parameters are listed in* **Table 5***; and (b) temperature and thermophysical-properties profiles along heated length of vertical tube: operating conditions in this figure correspond to those in (a); and thermophysical properties based on bulk-fluid temperature. Profiles of density, specific heat, thermal conductivity, and dynamic viscosity vs. temperature for SCW at pressure of 24.0 MPa are shown in* **Figure 11***.*


Meet the editors

Professor Mario Bernardo-Filho heads the Laboratory of Mechanical Vibrations and Integrative Practices (LAVIMPI), Roberto Alcantara Gomes Biology Institute, Department of Biophysics and Biometry, Piquet Carneiro University Polyclinic, State University of Rio de Janeiro (UERJ). He obtained his Ph.D. in 1988 and has been a full professor at UERJ since 1974. He supervises MSc and Ph.D. theses and has been a speaker at var-

ious national and international conferences. He is Editor in Chief of the *Brazilian Journal of Mechanical Vibrations in Biosciences* and a reviewer for several scientific journals indexed in PubMed and Scopus. He is interested in subjects related to exercises/physical activities and their biological effects in healthy and unhealthy individuals of different ages.

Redha Taiar, Ph.D., is a professor at the University of Reims Champaign, France. His research focuses on engineering for medicine and high-level sport. He has worked as an engineer for various industries including Arena for high-level sport and Sidas, Medicapteur for medical development. His most recent work in the industry involved the design and testing of Notrax anti-fatigue mats. In sport his most recent work focuses on

the development of swimsuits for triathletes and swimmers at the Brazil Olympic Games (2016) and Paris 2024, and ski-suit fabrics for the Winter Olympics at Sotchi in 2014. He is a specialist in the biomechanics of health disease and rehabilitation.

Prof. Técia Maranhão is a retired professor in the Obstetrics and Gynecology Department of the Science Health Center of the Federal University of the Rio Grande do Norte (UFRN). She obtained her Ph.D. in Obstetrics and Gynecology from the Faculty of Medicine of Ribeirão Preto, University of São Paulo in 1982. She is a member of the National Commission of Endocrine Gynecology of the Brazilian Federation of Obstetrics

and Gynecology and is on the Editorial Board of the *RBGO*. She lectures at various national and international conferences and is on the teaching staff of the Professional Master's Degree in Health Education. She works in the area of reproductive health and endocrine gynecology, and is currently researching polycystic ovary syndrome, insulin resistance and metabolic syndrome, and changes in female physical performance in hyperandrogenism.

Prof. Danúbia da Cunha de Sá-Caputo is a Research Project Coordinator at the Laboratory of Mechanical Vibrations and Integrative Practices (LAVIMPI) at the State University of Rio de Janeiro UERJ, Brazil. She obtained her MSc in 2015 and PhD in 2016. She supervises MSc and Ph.D. students and is a speaker at various national and international conferences. She is a reviewer of several scientific journals indexed in PubMed

and Scopus. Her research interests relate to exercises/physical activities and their biological effects on healthy and unhealthy individuals of different ages.


**1. Introduction**

Bisphenol A (BPA, CAS #80-05-7) is widely used in manufacturing polycarbonate plastics, epoxy resins, and thermal paper including food containers, baby bottles, dental sealant, and store receipts. BPA can produce the estrogenic activity through binding with estrogen receptor [1] and can also exert the actions through androgen receptor, peroxisome proliferator-activated receptor γ, and others [2]. Thus, BPA is classified as an endocrine disruptor (ED) because of the estrogenic potency.

Traditional toxicology considers that the effect would consistently increase with the amount of treatment. The dose levels of BPA below low observed adverse effects level (LOAEL) at 50 mg/kg/day [3] are regard as safe. However, recent studies describe the nonmonotonic dose response relationship of BPA. Perinatal exposure to lower dose of BPA than LOAEL has been reported the harmful effects on endocrine system including reproductive

system [4–7], immune system [8–10], pituitary gland [11–20], and metabolic system [21–24]. Because, the fetus and neonates are extremely sensitive to perturbation by hormone like chemicals, early life exposure to low dose BPA probably is able to affect the epigenetic mechanism. The epigenetic changes caused by BPA may explain the increased risk of developing adult onset diseases.

The mixed exposure to several low-level EDs should be tested because humans are exposed to various EDs simultaneously. Mixture can produce significant adverse effects, even when each chemical is present at low doses that individually do not induce observable effects in reproductive system [4, 25] neuroendocrine system [26], and endocrine system [27, 28].

Therefore, this chapter describes the harmful effects on adulthood caused by exposure to lowdose BPA during early life stage.


**Virendra Kumar Yadav, Krishna Kumar Yadav, Vineet Tirth, Govindhan Gnanamoorthy, Nitin Gupta, Ali Algahtani, Saiful Islam, Nisha Choudhary, Shreya Modi and Byong-Hun Jeon**

Extraction of Value-Added Minerals from Various Agricultural, Industrial and Domestic Wastes Reprinted from: *Materials* **2021**, *14*, 6333, doi:10.3390/ma14216333 .................. **135**


*β*-lactam Derivatives

These were the most tested, constituting 32.4% of all classes of antimicrobials in this study (Table 4). The β-lactam combinations consisted of β-lactam 27% and β-lactam combinations (β-lactam and β-lactamase inhibitors) at 5.4%. The combinations were supposed to improve the sensitivity of the antibiotics against resistant organisms. However, in this study, the organism tested demonstrated higher levels of resistance to β-lactam combinations (19/61) over β-lactam (80/308), which reported very high resistance levels (Table 4, Figure 3a, Figure S6). We observed Amoxycillin-clavunalic acid as one of the most studied β-lactam derivatives, with organisms showing the highest resistance levels to it among the β-lactam combinations, while Piperacillin-tazobactam was the most sensitive, with a lesser proportion of reports of resistance among β-lactam combinations (Tables 3 and 4, Figure 3a). Among the β-lactams, the third generation antibiotics were the most researched, with Ampicillin and Amoxycillin highest in study rate and also with the highest number of reported resistance, with above 50% of reports on them having very high resistance (Figure 3a, Figure S6). Among all β-lactam derivatives, cefalexin in second generation, Ceftioufur in third generation, and ertapenem in NGC were the only antimicrobials that had all reports on them to be "no resistance" (Figure 3a, Figure S6). All other β-lactams had various patterns of resistance level.


2.3.2. Light Transmittance

Light transmittance of the nanofiber suspensions was measured using a UV-Vis spectrophotometer (Specord 50 Plus, Analytik Jena AG, Jena, Germany). Well-dispersed CLCNF and LCNF suspensions (0.1 wt%) were placed in a cuvette with an optical path of 10 mm and the percent transmittance in the 400–800 nm wavelength range was recorded.


*Edited by Afef Najjari, Ameur Cherif, Haïtham Sghaier and Hadda Imene Ouzari*

This book focuses on the diversity and biotechnological applications of metabolites produced by extremophilic microbes thriving in different ecological niches citing the low troposphere, the gastrointestinal tract of ruminants, tropical dry forest, and saline ecosystems. These studies were based on metabolomics and molecular approaches like metagenomics and single-cell genomic analyses. Various implications of Electro-Rheological Fluid are also discussed. The editor embarked on this writing project entitled "*Extremophilic Microbes and Metabolites - Diversity, Bioprospecting, and Biotechnological Applications*" to make pertinent contributions accessible to the scientific community. Hopefully, a large audience will benefit from the chapters of this book.

Published in London, UK © 2021 IntechOpen © Irochka\_T / iStock

Extremophilic Microbes and Metabolites - Diversity, Bioprospecting

and Biotechnological Applications

Extremophilic Microbes

and Metabolites

Diversity, Bioprospecting and Biotechnological

Applications

*Edited by Afef Najjari, Ameur Cherif,*

*Haïtham Sghaier and Hadda Imene Ouzari*


Standards, Methods and Solutions of Metrology

*Edited by Luigi Cocco*

Published in London, United Kingdom

## *Supporting open minds since 2005*

Standards, Methods and Solutions of Metrology http://dx.doi.org/10.5772/intechopen.77475 Edited by Luigi Cocco

Contributors

Denis Sullivan, Khalil Ebrahim Jasim, Imed Gargouri, Moncef Khadhraoui, Fatma Omrane, Oleh Velychko, Tetyana Gordiyenko, Chuxiong Hu

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First published in London, United Kingdom, 2019 by IntechOpen IntechOpen is the global imprint of INTECHOPEN LIMITED, registered in England and Wales, registration number: 11086078, The Shard, 25th floor, 32 London Bridge Street London, SE19SG – United Kingdom Printed in Croatia

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**2.2 Thymopoiesis: the result of cross-talk between thymic stromal cells and precursor T cells**

T cell progenitors that lack both CD4 and CD8 receptors are termed as doublenegative (DN) cells. These cells separate from the bone marrow, enter the thymus through the large venules located at the corticomedullary junction (CMJ), and settle into the cortex of the thymus. In the thymic cortex, the rearrangement at T cell receptor (TCR) α and β genes makes the cells turn into double-positive (DP) stage, when cells express both CD4 and CD8. Then, a positive selection process directs DP cells into either CD4+ or CD8+ T cells depending on their affinity for either major histocompatibility complex (MHC) protein class II or I, respectively. The thymus selects single-positive (SP) immunocompetent T cells to export them out of the thymus. In the periphery, these naïve self-restricted T cells eventually home to secondary lymphoid organs. To bear the name of its creators, i.e., thymocytes, this process of manufacturing mature functional T cells is generally recognized as thymopoiesis.

### **2.3 Thymic mechanisms of central self-tolerance**

#### *2.3.1 Positive selection takes place in the thymic cortex*

The positive selection is defined as a process through which SP T cells expressing either CD4 or CD8 are selected. The thymic cortex carries gene rearrangements that make precursor T cells co-express CD4 and CD8. These DP T cells are then engaged by a ligand bound to an MHC class II or I molecule that is present on cTECs and will be differentiated into SP T cells that express either CD4 or CD8, correspondingly [6].

#### *2.3.2 Negative selection takes place in the thymic medulla*

The negative selection is simply a process by which autoreactive T cells are removed. After positive selection is done, the transfer of SP T cells from the cortex to the medulla occurs. The expression of chemokine receptor CCR7 by T cells is

**3**

*Introductory Chapter: Thymus - The Central Self-Tolerance System*

reactive to self to shift from the thymus to the periphery [6].

*2.3.3 Agonist selection takes place in the thymic medulla*

consequently regulates inflammatory responses [6].

**3.1 The effects of thymic infection on thymopoiesis**

**does not work?**

*3.1.1 The thymus gets sick*

essential to the transfer process—since antigen-presenting cells (APCs) including mTECs and dendritic cells in the medulla express CCR7 ligands, e.g., CCL19 and CCL21. In this manner, SP T cells can engage in interaction with medullary APCs that present a variety of tissue-restricted antigens (TRAs). Medullary APCs are responsible for finding autoreactive T cells that recognize self-antigen—MHC complexes and their removal. Such selection would permit SP T cells that are not

The agonist selection is also undertaken by the thymic medulla to allow a portion

of autoreactive CD4+ T cells to differentiate into regulatory T (Treg) cells that express forkhead box P3 (Foxp3). These regulatory T cells that are derived from the thymus are referred to as tTreg cells and move from the thymus to the peripheral tissues. They constitute the majority of all Treg cells and play the central role in immune tolerance. So, the thymus must be precisely effective in the generation of Treg cells. If this could not be achieved, then we see the process of autoimmunity. However, there are Treg cells derived from peripheral tissues referred to as pTreg cells. This type of Treg cells is especially accumulated at sites of inflammation and

**3. If peace is in the hands of the thymus, then what would happen if that**

The thymus-mediated effects including the production of neuropeptides and also development of T cell repertoire are what may be called the function of the pacemaker [7]. However, the thymus is vulnerable to be exposed to both acute and chronic injuries. A variety of pathological conditions that range from infections and immunodeficiency to inflammatory and autoimmune disorders and tumors may cause the thymus to turn into malfunctioning or functionless. In a broader sense, the thymus undergoes physiological changes that occur with age and during pregnancy. Below is to represent dysregulation of immune homeostasis as the inevitable

consequence of a failure in central self-tolerance system, i.e., the thymus.

The thymus is not immune-privileged, but rather invading pathogens can adversely affect its structure and/or function, thymopoiesis, through indirect (systemic) and direct (local) ways. Pathogens that are able to penetrate into the different thymic location(s), e.g., cortex, CMJ, or medulla, and thereby directly infect thymic cells, include a number of viruses (human immunodeficiency virus, *Simian immunodeficiency virus*, influenza virus, lymphocytic choriomeningitis virus, *Murine leukemia virus*, mouse hepatitis virus, human cytomegalovirus, measles virus, coxsackievirus, Epstein-Barr virus, Junin virus, and poliovirus), bacteria (*Mycobacterium avium*, *Mycobacterium tuberculosis*, *Francisella tularensis*, and *Salmonella enterica*), fungi (*Paracoccidioides brasiliensis* and *Cryptococcus neoformans*), and parasites (*Trypanosoma cruzi*, *Plasmodium berghei*, and *Toxoplasma gondii*). In addition, pathogens can act indirectly by altering the systemic expression of glucocorticoids, cytokines, chemokines, and antigens. Then, these soluble factors can reach the village

of the thymus and readily result in changes of its microenvironment [8].

*DOI: http://dx.doi.org/10.5772/intechopen.90491*

*Introductory Chapter: Thymus - The Central Self-Tolerance System DOI: http://dx.doi.org/10.5772/intechopen.90491*

*Thymus*

**2.1 Immunological tolerance**

*2.1.1 Central tolerance*

*2.1.2 Peripheral tolerance*

helplessness, and suppression.

**2.3 Thymic mechanisms of central self-tolerance**

*2.3.1 Positive selection takes place in the thymic cortex*

*2.3.2 Negative selection takes place in the thymic medulla*

**precursor T cells**

**2. How does the thymus teach T lymphocytes self-tolerance?**

To keep the body healthy, the immune system is expected to entail invading pathogens while avoiding reactivity to self-tissues. This so-called immunological tolerance engages both central and peripheral modes of action (for review, see [5]).

It is referred to immature B and T cells when they are present in the primary lymphoid organs—B cells in the bone marrow and T cells in the thymus. Mechanisms of central tolerance are, for example, clonal deletion and elimination of self-reactive cells.

This one is for mature B and T cells as detached from the primary lymphoid organs into the bloodstream, lymph, and secondary lymphoid organs such as spleen and lymph nodes. There are various mechanisms that can promote tolerance in the periphery, including clonal deletion, clonal anergy, clonal ignorance, deviation,

**2.2 Thymopoiesis: the result of cross-talk between thymic stromal cells and**

T cell progenitors that lack both CD4 and CD8 receptors are termed as doublenegative (DN) cells. These cells separate from the bone marrow, enter the thymus through the large venules located at the corticomedullary junction (CMJ), and settle into the cortex of the thymus. In the thymic cortex, the rearrangement at T cell receptor (TCR) α and β genes makes the cells turn into double-positive (DP) stage, when cells express both CD4 and CD8. Then, a positive selection process directs DP cells into either CD4+ or CD8+ T cells depending on their affinity for either major histocompatibility complex (MHC) protein class II or I, respectively. The thymus selects single-positive (SP) immunocompetent T cells to export them out of the thymus. In the periphery, these naïve self-restricted T cells eventually home to secondary lymphoid organs. To bear the name of its creators, i.e., thymocytes, this process of manufacturing mature functional T cells is generally recognized as thymopoiesis.

The positive selection is defined as a process through which SP T cells expressing either CD4 or CD8 are selected. The thymic cortex carries gene rearrangements that make precursor T cells co-express CD4 and CD8. These DP T cells are then engaged by a ligand bound to an MHC class II or I molecule that is present on cTECs and will be differentiated into SP T cells that express either CD4 or CD8, correspondingly [6].

The negative selection is simply a process by which autoreactive T cells are removed. After positive selection is done, the transfer of SP T cells from the cortex to the medulla occurs. The expression of chemokine receptor CCR7 by T cells is

**2**

essential to the transfer process—since antigen-presenting cells (APCs) including mTECs and dendritic cells in the medulla express CCR7 ligands, e.g., CCL19 and CCL21. In this manner, SP T cells can engage in interaction with medullary APCs that present a variety of tissue-restricted antigens (TRAs). Medullary APCs are responsible for finding autoreactive T cells that recognize self-antigen—MHC complexes and their removal. Such selection would permit SP T cells that are not reactive to self to shift from the thymus to the periphery [6].


*Article* **ARBIN: Augmented Reality Based Indoor Navigation System**

#### **Bo-Chen Huang 1 , Jiun Hsu 2 , Edward T.-H. Chu 1,\* and Hui-Mei Wu 2**

Received: 27 August 2020; Accepted: 12 October 2020; Published: 17 October 2020

**Abstract:** Due to the popularity of indoor positioning technology, indoor navigation applications have been deployed in large buildings, such as hospitals, airports, and train stations, to guide visitors to their destinations. A commonly-used user interface, shown on smartphones, is a 2D floor map with a route to the destination. The navigation instructions, such as turn left, turn right, and go straight, pop up on the screen when users come to an intersection. However, owing to the restrictions of a 2D navigation map, users may face mental pressure and get confused while they are making a connection between the real environment and the 2D navigation map before moving forward. For this reason, we developed ARBIN, an augmented reality-based navigation system, which posts navigation instructions on the screen of real-world environments for ease of use. Thus, there is no need for users to make a connection between the navigation instructions and the real-world environment. In order to evaluate the applicability of ARBIN, a series of experiments were conducted in the outpatient area of the National Taiwan University Hospital YunLin Branch, which is nearly 1800 m2 , with 35 destinations and points of interests, such as a cardiovascular clinic, x-ray examination room, pharmacy, and so on. Four different types of smartphone were adopted for evaluation. Our results show that ARBIN can achieve 3 to 5 m accuracy, and provide users with correct instructions on their way to the destinations. ARBIN proved to be a practical solution for indoor navigation, especially for large buildings.

**Keywords:** augmented reality; Bluetooth; indoor positioning system; indoor navigation system; smart hospital


**Acknowledgements**

This work was supported by grants-in-aid from Projects of the National Natural Science Foundation (81673241, 81702419), the Jiangsu Health Plans (2014-YY-028 and BE2016698), the Jiangsu Graduate Innovation Plan (KYCX17\_1934), the Nantong Science Foundation of Health and Family Planning Commission (WQ2016083), and the International Science & Technology Cooperation Program (2013DFA32150) of China.


*Article* **Architecture Insight of Bifidobacterial** α**-L-Fucosidases**

**José Antonio Curiel \* , Ángela Peirotén , José María Landete , Ana Ruiz de la Bastida, Susana Langa and Juan Luis Arqués**

> Departamento de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Carretera de La Coruña Km 7.5, 28040 Madrid, Spain<EMAIL_ADDRESS>(Á.P<EMAIL_ADDRESS>(J.M.L<EMAIL_ADDRESS>(A.R.d.l.B<EMAIL_ADDRESS>(S.L<EMAIL_ADDRESS>(J.L.A.) **\*** Correspondence<EMAIL_ADDRESS>Tel.: +34-91-347-68-86

**Abstract:** Fucosylated carbohydrates and glycoproteins from human breast milk are essential for the development of the gut microbiota in early life because they are selectively metabolized by bifidobacteria. In this regard, α-L-fucosidases play a key role in this successful bifidobacterial colonization allowing the utilization of these substrates. Although a considerable number of α-L-fucosidases from bifidobacteria have been identified by computational analysis, only a few of them have been characterized. Hitherto, α-L-fucosidases are classified into three families: GH29, GH95, and GH151, based on their catalytic structure. However, bifidobacterial α-L-fucosidases belonging to a particular family show significant differences in their sequence. Because this fact could underlie distinct phylogenetic evolution, here extensive similarity searches and comparative analyses of the bifidobacterial α-L-fucosidases identified were carried out with the assistance of previous physicochemical studies available. This work reveals four and two paralogue bifidobacterial fucosidase groups within GH29 and GH95 families, respectively. Moreover, *Bifidobacterium longum* subsp. *infantis* species exhibited the greatest number of phylogenetic lineages in their fucosidases clustered in every family: GH29, GH95, and GH151. Since α-L-fucosidases phylogenetically descended from other glycosyl hydrolase families, we hypothesized that they could exhibit additional glycosidase activities other than fucosidase, raising the possibility of their application to transfucosylate substrates other than lactose in order to synthesis novel prebiotics.

**Keywords:** bifidobacteria; fucosidases; glycosyl hydrolases; conserved domains; human milk