**Abstract**

Pharmacogenomics represents an attempt to optimize the efficacy of drugs, minimize adverse drug reactions, and facilitate drug discovery, development, and approval. Understanding an individual's genetic makeup can be the key to creating personalized drugs with greater efficacy and safety, as pharmacogenetic testing can be used to identify individuals who may be more susceptible to adverse drug reactions. Interindividual variability in the pharmacokinetics of many medicinal products is prone to interindividual variability. Pharmacogenomics should be considered one of the factors affecting the pharmacokinetics of a drug. When a polymorphism in a metabolizing enzyme and/or transporter causes a difference in exposure, it may alter efficacy or safety.

**Keywords:** pharmacogenomics, pharmacokinetics, pharmacology, drug, genetic testing


**3. Worldwide status of geothermal power production**

By the end of 2018, the cumulative global installed capacity of geothermal power amounted to 13.28 GW generated an annual electrical energy of about 86 TWh. Geothermal resource has contributed significantly in electricity production in some regions; 17% of New Zealand's electricity production and 31% of Iceland's electricity production was met by geothermal in 2018 [44]. In 2020, the global additions of geothermal capacity are estimated at 300 MW. Indonesia and Turkey led the new development, with 145 MW and 70 MW of capacity added for the two countries, respectively. The technology is forecast to reach 16.5 GW of aggregate capacity worldwide by 2022 [45]. While United Stated of America has been at the top world rank in terms of geothermal power capacity [46], Turkey, Kenya, Indonesia and the Philippines would be responsible for most of the technology growth and continue to lead capacity additions beyond 2022. Geothermal power cumulative capacity and additions in leading countries are depicted in **Figure 6** [44].

*Geothermal power capacity and additions in top countries by 2018 [44].*

Geothermal technology exploitation depends primarily on the resource potential and economic considerations, but generally, most existing geothermal facilities worldwide use flash or dry-steam technologies. However, on global scale, binarycycle technology has been the fastest progressing technology in recent time, due in part to rising utilization of relatively low-temperature resources [44]. Direct Use i.e., thermal energy consumption of geothermal energy technology is one of the common and versatile form of utilizing the underground heat [47]. The installed global total of geothermal power capacity for Direct Use sectors is estimated at 26 GWt at the end of 2018 [44].

The distribution of geothermal Direct Use applications is categorized as: 58.8% for heat pumps, 18% for bathing and swimming, 16% for space heating, 3.5% for greenhouse heating, 1.6% for industrial applications, 1.3% for raceway heating and aquaculture pond, while the remainder goes to other applications such as agricultural drying and snow melting and cooling, etc. [47]. Geothermal heat pumps have the greatest geothermal utilization worldwide, accounting for 59.2% of the annual energy use and 71.6% of the installed capacity by 2020. The installed capacity for geothermal based heat pumps approaching 77,547 MWt mostly built in North America, Europe and China. The size of individual systems ranges from 5.5 kW for residential installation to greater than 150 kW for commercial and institutional units [47]. Most heat pumps systems in Europe are sized for the heating load that are designed to meet the base load, with surging by fossil fuels. In Finland, as an example, some of these units reached an operation of up to 3,000 equivalent fullload heating hours per year i.e., a capacity factor of 0.34.

Space heating, including district heating and individual space heating, has now an installed capacity of 12,768 MWt and an annual energy use of 162,979 TJ/yr. In terms of annual energy use, the leaders are Turkey, Russia, Japan, the United States,

#### **Table 4.**

*MWt and leading states for various categories of direct-utilization for the year 2020 [4].*

#### *Geothermal Power Generation DOI: http://dx.doi.org/10.5772/intechopen.97423*

and Switzerland, accounting for about 75% of the world's individual space heating and nearly 90% of the world's total use in district heating. Deep Direct Use or what is alternatively called Cascaded Use offers large-scale viable systems that optimize the value stream of lower temperature resources through a multiple of purposes, from electricity production to direct cooling and heating, commercial and industrial applications, etc. [46]. **Table 4** provides a summary of the installed capacity factor (in MWt), and leading states for various categories of Direct Use for the year 2020.


Cement Industry - Optimization, Characterization and Sustainable Application

*Edited by Hosam El-Din Mostafa Saleh*

Published in London, United Kingdom

## *Supporting open minds since 2005*

Cement Industry - Optimization, Characterization and Sustainable Application http://dx.doi.org/10.5772/intechopen.87890 Edited by Hosam El-Din Mostafa Saleh

#### Contributors

Hilal El-Hassan, M.Jemimah Carmichael, G. Prince Arulraj, Shankar Sabavath, Chakravarthi Sarella, Raj Kumar Galipelli, Muhammad Imran Khan, Muslich Hartadi Sutanto, Madzlan Bin Napiah, Salah E. Zoroob, Michael Mikheenkov, Oleg Sheshukov, Gude Reddy Babu, Nelluru Venkata Ramana, Bhumireddy Madhusudana Reddy, Pala Gireesh Kumar, Ahed Habib, Maan Habib, Jaime Andres Perez Taborda, Jorge Hernan Quintero Orozco, Daniel Andres Triana Camacho, Michal Bacuvcik, Pavel Martauz, Ivan Janotka, Branislav Cvopa, Oluwafemi Fadayini, Adekunle Adedapo Obisanya, Gloria Ajiboye, Clement Madu, Tajudeen Ipaye, Taiwo Rabiu, Joseph Taiwo Akintola, Shola John Ajayi, Taiwo Oshin, Adekunle Obisanya, Nkechi Alexandra Kingsley, Hosam M. M. Saleh, Abeer M. El-Sayed, Abeer A. Faheim, Aida A. Salman

#### © The Editor(s) and the Author(s) 2021

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**1. Introduction**

In late December 2019, when international news reported on a virus that had apparently anecdotally been caused by bats; little did the world know how coronavirus disease would lead to so much social and economic disruption across the world. The impact on day-t0-day living was significant; including restrictions on travel and movement, social distancing, work practices that in many cases included working from home, and 'lockdown' in terms of normal social functioning, including the closure of school buildings. While there is no doubt that the pandemic, which at the time of writing, according to the United Nations has led to 15 million deaths worldwide and "disrupted the essential health services of 92% of countries" [1] (2022, page 10), the research reported in this chapter focuses on the perceived impacts experienced by a small sample of Irish primary school teachers and principals as they navigated their way through the pandemic supporting their students, schools and families in their

local context. This chapter reports the findings of a mixed-methods study undertaken with Irish primary school principals and teachers. While the study involved a mixedmethods approach comprising self-reported questionnaires and semi-structured interviews, one of the interesting sub-themes identified in the qualitative data and focused on for this chapter, was 'impacts and opportunities'. This theme that was identified within the larger well-being theme refers to how the participants described the opportunity the pandemic provided for them in some cases to address their own well-being and engage in self-care practices The overall aim of the study was to provide an opportunity for both principals and teachers to reflect on how the pandemic impacted on their well-being and by inference, emerging issues in the school community as a result of Covid 19. We begin this chapter with a background summary of the timeline of school closures in the Irish context, followed by a brief discussion of theoretical perspectives of well-being, and a brief review of relevant literature pertaining to the themes of social emotional well-being, care practices and more specifically self-care practices. We acknowledge the ongoing debate as to the meaning of the term "well-being", and highlight the Irish Department of Education (DE) [2] definition as applied in Irish education contexts. The research methodology and findings related to the impacts and opportunities are then presented and discussed. A large portion of the findings section is devoted to the original narratives of the participants, but these serve to illuminate the narratives, resulting in rich data findings from then participants. Finally, the implications for supporting teacher and principal well-being are discussed with recommendations for future research.


**3. Nucleate pool boiling**

Nucleate pool boiling is the first type of boiling to be used by humans and the first one to be investigated. Boiling curve for saturated water at the atmospheric pressure was obtained by Professor Shiro Nukiyama (Tohoku University, Japan) at the beginning of 1930s and for long time was called as the "Nukiyama's boiling curve" (see **Figure 1**). In the current view the boiling curve is updated with *q*max and *q*min values and melting temperatures of some common metals/alloys. Photos of nucleate pool boiling are shown in **Figures 3** and **4**.

Major nucleate-pool-boiling characteristics (see **Figure 1**) are as the following:

#### **Figure 6.**

*Wall- and bulk-fluid-temperature and pressure-loss-gradient profiles in uniformly heated vertical, bare tube at flow boiling (based on Figure 4 from Siemens: 25JahreBENSONbild\_E.doc [Accessed: February 22, 2022]).*

*Advances and Challenges of Boiling Heat Transfer DOI: http://dx.doi.org/10.5772/intechopen.114095*

#### **Figure 7.**

*Critical-heat-flux (CHF) profiles vs. pressure in uniformly heated vertical, bare tube at flow boiling (upper solid curve) and in pool boiling (lower dashed curve).*

#### **Figure 8.**

*Flow boiling of water in vertical rectangular channel (8 12.5 730 mm; two opposite walls—st. st. and other two—transparent acrylic): Pressure 0.1 MPa; inlet velocity 0.036 m/s; subcooling temperature 90°C; heat flux 167 kW/m2 ; scale—height of each photo equals to 150 mm in actual test section; width 12.5 mm; from left to right—portions of channel from lower to upper part starting from 130 mm of heated length. Vapor bubbles on photos are shown as black circles. Flow regimes from left bottom to right top (approximately): Bubbly flow; slug flow; annular flow; annular flow with entrainment of droplets; and single-phase steam flow. Liquid film on left and right st. st. walls moves up in photos 2–4.*

#### **Figure 9.**

*Bulk boiling in two-phase counter-flow thermosyphon on glass surface: Methylene chloride (R-30), atmospheric pressure, filling charge more than 100% of evaporator volume, evaporator—lower part of thermosyphon and condenser—upper part, in between—short transportation zone), and heat flux increasing from left to right.*

#### **Figure 10.**

*Nucleate boiling in two-phase counter-flow thermosyphon on st. st. surface: Methylene chloride (R-30), atmospheric pressure, filling charge more 40% of evaporator volume, and heat flux increasing from left to right up to critical heat flux (CHF).*

*Advances and Challenges of Boiling Heat Transfer DOI: http://dx.doi.org/10.5772/intechopen.114095*

**Figure 11.**

*Nucleate boiling in two-phase counter-flow thermosyphon on metal heated rod (annular-channel evaporator): Water, atmospheric pressure, filling charge 100% of evaporator volume, and heat flux increasing from left to right up to critical heat flux (CHF).*

Therefore, for all these Points /Regions we need to have the appropriate correlations (for general correlations, see, for example, Chapter 10 in [9]). In general, there are three internal boiling characteristics such as (for details, see [23–27]; and **Table 1**): (1) vapor-bubble departure diameter, *D*b; (2) frequency of vapor-bubbles departure, *f*; and (3) mean velocity of vapor-bubble growth, *u*b = *D*b *f*b. However, these internal-boiling characteristics are not easy to estimate, and their uncertainties

#### **Figure 12.**

*Nucleate boiling in two-phase counter-flow thermosyphon on metal heated rod (annular-channel evaporator): Water-ethylene-glycol mixture (water boiling temperature 100°C and ethylene-glycol—200°C), atmospheric pressure, filling charge 100% of evaporator volume, and heat flux increasing from left to right up to critical heat flux (CHF). Photo 1: no boiling—mixture not separated; photos 2–9—mixture is separated, i.e., water (liquid density—958 kg/m3 ) boils in the upper part of evaporator and non-boiling ethylene-glycol as liquid (density— 993 kg/m3 ) transfers heat to boiling water with natural convection in the lower part.*

are quite high. Also, there are some theoretical approaches to boiling heat transfer, but, usually, only empirical correlations are used for various nucleate-pool-boiling characteristics/parameters, which are based on well-known and well-defined thermophysical properties. For example, the vapor-bubble departure diameter is usually replaced with [9]:

$$D\_{\mathbf{b}} \propto \sqrt{\frac{\sigma}{\mathbf{g}\left(\rho\_f - \rho\_\mathbf{g}\right)}}.\tag{1}$$

In 1952, W. Rohsenow has proposed his nucleate pool-boiling correlation, which is the most widely used correlation during the last 70+ years.

*Advances and Challenges of Boiling Heat Transfer DOI: http://dx.doi.org/10.5772/intechopen.114095*

#### **Figure 13.**

*Universal experimental setup for boiling experiments at various operating conditions and in different flow geometries (current view—test section (to the left) is two-phase counter-flow thermosyphon: 1—condenser; 2 cooling jacket; 3—coolant (antifreezing mixture water-ethylene glycol); 4—transportation (adiabatic) zone; 5 working fluid (WF); 6—evaporator; 7—current terminals; 8—insulation; 9—sheathed thermocouples (fluid/ vapor temperatures); 10—wall-temperature thermocouples; A—ammeter; G—electrical generator (power supply); V—voltmeter; and VP—vacuum pump.*

The main concept of this correlation is that the heat transfer from the wall directly to the liquid with an increased heat-transfer rate, due to the agitation of liquid by the departing vapor bubbles.

$$\frac{c\_{p\\_f}\ \Delta T\_b}{H\_{\rm f\underline{g}}} = \mathcal{C}\_{\rm f\\_} \left[\frac{q}{\mu\_{\rm f}\ H\_{\rm f\underline{g}}} \sqrt{\frac{\sigma}{\mathcal{g}\left(\rho\_f - \rho\_{\rm g}\right)}}\right]^m \left(\frac{c\_{p\\_f}\ \mu\_f}{k\_{\rm f}}\right)^n,\tag{2}$$

where *Csf* is constant, depending upon the nature of the heating-surface- fluid combination (see **Table 2**). However, some other well-known correlations do not include any heating-surface parameters/properties or impact of the heating-surface- fluid combination on HTC at boiling (for details, see [10]).

Detailed analysis of the data in **Table 2** has shown that information on the surfacefluid combination is too simplified and, actually, misleading. A thorough analysis of original publications in which *C*sf values were obtained is presented in the joint

#### **Figure 14.**

*Test sections for boiling experiments at various operating conditions: (a) two-phase counter-flow glass thermosyphon (bulk-boiling photos—Figure 9); (b) two-phase counter-flow thermosyphon with boiling on st. st. surface (nucleate-boiling photos—Figure 10); (c) two-phase counter-flow glass thermosyphon with multiple evaporators and horizontal condenser); and (d) two-phase counter-flow thermosyphon with boiling on st. st. internal tube (annular boiling channel) (nucleate-boiling photos—Figures 11 and 12):—fluid-expansion tank; 2—cooling jacket; 3—condenser; 4—heating jacket; 5—evaporator; and 6—current (power) terminals.*

publication by I. Pioro, W. Rohsenow, and S. Doerffer [10, 23] and by Pioro [8] together with the latest Pioro correlation on the pool-boiling heat transfer. This list of *C*sf values is the most comprehensive and detailed one so far (see Appendix A at the end of this Chapter).

The major problem with correlations, which account for a heating surface-fluid combination, is that these correlations can be used only for a particular heating surface and fluid used in experiments. Otherwise, uncertainties can be very high! On opposite, if correlations, which do not account on a particular heating surface and fluid combination, are used, it is impossible to predict uncertainties of HTCs calculated!

The most important nucleate-pool-boiling characteristic is the Critical Heat Flux (CHF), because if the CHF is reached, the boiling-surface temperature can jump to very high values (beyond 1000°C, see **Figure 1**) and, eventually, the boiling surface can be damaged or even melted. Of course, this temperature rise depends on the type of heating, i.e., for electrical and nuclear heating temperature rise can go far beyond 1000°C. However, if the boiling surface is heated with hot or high-temperature medium, the surface temperature cannot be higher than that of this medium.

The mostly used CHF correlation for pool boiling is as the following (for details, see **Figure 7**):

$$q\_{\rm cr} = \mathcal{C}\_{\rm cr} H\_{\rm fg} \left[ \sigma \mathbf{g} \rho\_{\rm g}^2 \left( \rho\_{\rm f} - \rho\_{\rm g} \right) \right]^{0.25},\tag{3}$$

where *C*cr is constant with the average value of 0.15. However, in reality, this constant can be within the range of 0.08–0.28! This correlation was obtained through a dimensional analysis by S.S. Kutateladze in Russia in 1948 and through a hydrodynamicstability analysis by N. Zuber in the United States in 1958 [9].

Therefore, in conclusion we can say that in spite of more than 100 years of active research into the pool-boiling phenomena, we have failed to develop universal HTC,

*Advances and Challenges of Boiling Heat Transfer DOI: http://dx.doi.org/10.5772/intechopen.114095*

#### **Figure 15.**

*a-e. Electron-microscope images (enlargement 100) of plates made of: (a) aluminum—*R*q = 4.5 μm,* R*sk = 0.47 μm; (b) copper—*R*q = 1.7 μm,* R*sk = 0.38 μm; (c) brass—*R*q = 0.7 μm,* R*sk = 1.3 μm; (d) st. st.—* R*q = 0.6 μm,* R*sk = 0.19 μm; and (e) polyethylene high density. For thermophysical properties and surfaceroughness parameters, see Tables 3 and 4, respectively, and Appendix A). Details on experimental setup with these heated plates and experimental data are presented in [8]. f. Effect of heat flux on HTC at nucleate pool boiling of R-11 on copper (*Rq *= 1.7 μm) (b) and plastic (PHD) (e) large-size plates.*

CHF, minimum heat flux, film boiling, and other correlations with a reasonable accuracy, which can be applied to various heating surfaces with different thermophysical properties, surface-roughness parameters and microgeometry, wall thickness, orientation in space, and different boiling fluids within a wide range of operating conditions!

The thermophysical properties of boiling surfaces are listed in **Table 3**.

#### **Figure 16.**

*Effect of gravity on boiling heat transfer and CHF in horizontal tube: Water,* P *= 10 MPa,* G *= 500 kg/m2 s,* D *= 24.3 mm (based on Kohler and Hein [11]) (Courtesy of NRC, USA).*

*Advances and Challenges of Boiling Heat Transfer DOI: http://dx.doi.org/10.5772/intechopen.114095*

**Table 1.**

*Internal boiling characteristics of various fluid-surface combinations [23, 24].*

#### **Table 2.**

*Values of* C*sf for various surface-fluid combinations [9].*

#### **Table 3.**

*Thermophysical properties of boiling surfaces (extended plates) at 27°C (listed according to decreasing thermalconductivity values) [9].*

A laser profilometer was used to determine the surface-roughness parameters that are listed in **Table 4**. The characteristics of the laser profilometer itself were as follows:

**Table 4.**

*Average surface-roughness parameters of boiling surfaces (extended plates) (listed according to decreasing surfaceroughness (*R*q/*R*a) values) (for descriptions of all surface roughness parameters, see below or in [10]).*

#### *Explanations to* **Table 4***.*

Simple-Roughness-Amplitude Parameters.

*Mean parameters.*

*R*a average roughness: area between the roughness profile and its mean line or its integral of the absolute value of the roughness-profile height over the evaluation length. The average roughness is the most commonly used parameter in surface-finish measurements.

*R*q root-mean-square roughness (rms roughness): average roughness parameter calculated as a square root from another integral of the surface-roughness profile. Root-mean-square roughness was a commonly used parameter in the past; however, nowadays it has been replaced with *R*a in metal-machining specifications. Usually (but not necessarily), *R*q is 1.1–1.3 times larger than *R*a.

*Extreme parameters.*

*R*p peak roughness (height of the highest peak in the roughness profile over the evaluation length).

*R*v depth roughness (depth of the deepest valley in the roughness profile over the evaluation length).

*R*t total roughness (vertical distance from the deepest valley to the highest peak), *R*t = *R*p + *R*v.

*Mean-extreme parameters.*

*R*pm mean-peak roughness (average peak roughness over the sample length).

*R*z mean-total roughness (average value of the five highest peaks plus the five deepest valleys over the evaluation length).

*R*z3 mean-total roughness of third extremes parameters (average vertical distance from the third deepest valley to the third highest peak).

Mean-extreme parameters are less sensitive to single unusual features, such as artificial scratches, gouges, burrs, etc.

*Roughness-spacing parameters.*

*HPC* High-Peak Count per length (number of peaks per length that cross above a certain threshold and then go back below it).

*Mean-roughness-spacing parameters.*

*S*m mean spacing between peaks (peaks cross above a mean line and then go back below it).

*λ*a average wavelength of surface.

*λ*q rms (root-mean-square) average wavelength of surface.

*Roughness-hybrid parameters.*

*Δ*a average of absolute slope of roughness profile over the evaluation length. *L*o actual profile length (in all measurements, this was 8 mm).

Statistical parameters.

*R*sk skewness (this parameter represents the profile variation symmetry over its mean line). Surfaces with *R*sk < 0 have fairly deep valleys in a smoother plateau. Surfaces with *R*sk > 0 have fairly high spikes, which protrude above a flatter average.

## **4. Flow boiling**

Flow boiling is boiling with forced convection, which is the most used type of boiling in industry [28], especially, in thermal- and nuclear-power industry [29, 30] and air-conditioning and refrigeration industry [31, 32]. In the thermal-power industry gas-fired and coal-fired (or fossil-fuel-fired) power plants are used, many of which equipped with the subcritical-pressure Rankine steam-turbine cycle (see **Figure 17a**) [33, 34]. In nuclear-power industry of the world there are 441 nuclear-power reactors connected to electrical grids of which 60 reactors are Boiling Water Reactors (BWRs) including several Advanced BWRs (ABWRs). Moreover, all current nuclear-power reactors are connected only to Rankine steam-turbine power cycles in which boiling takes place in steam generators (in BWRs and ABWRs saturated steam is generated inside reactors (for details, see **Figures 17b**, **18**, and **19**).

More information on all current and future nuclear-power reactors and their power cycles can be found in [29].

The main advantage of using flow or forced-convection boiling is very high HTCs compared to other types of heat transfer (see **Table 5**).

Major flow-boiling characteristics (see **Figure 6**) are as the following:

In general, these flow-boiling characteristics are quite similar to those of pool boiling. It is impossible to provide correlations for all cases of pool boiling as well as of flow boiling. However, this Chapter contains a list of references and bibliography, which have quite a large number of various cases covered and correlations provided.

**Figures 20**–**23** show specifics of flow boiling in circular tubes, and the experimental setup for these experiments is shown in **Figure 24**. This study covers only two fluids: water and R-134a. To enable a comparison of CHF results between water and R-134a, the R-134a results were converted to their water-equivalent values using the following CHF fluid-to-fluid modeling relationships. It has been shown for vertical

#### **Figure 17.**

*Temperature (*T*) vs. specific entropy (*s*) simplified diagram of subcritical-pressure Rankine power cycle: (a) fossil-fuel-fired thermal power plant with superheated primary- and secondary-steam reheat and (b) advanced boiling water reactor (ABWR) with saturated primary steam and overheated secondary-steam (see Figure 19). Abbreviations: HPT—high-pressure turbine; LP—low pressure; MS—moisture separator; RH—re heater; SG steam generator; and SHS—super heated steam.*

*Advances and Challenges of Boiling Heat Transfer DOI: http://dx.doi.org/10.5772/intechopen.114095*

#### **Figure 18.**

*Heat-transfer tubes are installed into steam generator (SG) of PWR (1110 MWel and 3060 MWth) (in total four SGs per one reactor) (courtesy of Rosatom): https://www.flickr.com/photos/rosatom/36999718643/in/album-72157675727427445/ [Accessed: December 10, 2023]; Photo by E. Lyadov, Atommash, 2016.*

*Reactor coolant is inside tubes and Rankine-cycle feedwater heated and boiling outside tubes.*

tubes (see in [36]) that if the fluid-to-fluid modeling relationships are satisfied, i.e., *L*R = *L*W, *D*R = *D*W (geometric similarity),

*xcr R* ¼ *xcr W* (thermodynamic similarity), then the dimensionless CHF expressed as *qcr G hfg* " # *R* ¼ *qcr G hfg* " # *W* will also be the same for both fluids. Even though the study deals

with experiments in R-134a, the water CHF look-up table is also used as a reference, as this table represents an already normalized CHF database for water.

The look-up table data were normalized to tubes with an 8 mm ID; to obtain the CHF for a different diameter, a simple correction can be applied: *CHFD CHFD*¼8 *mm* ¼ *D* 8 � ��0*:*5 , where *D* is the Inside Diameter (ID) of a circular tube in mm, *D* = 8 mm is the reference tube ID.

#### **Figure 19.**

*Simplified layout of typical boiling water reactor (BWR) NPP (courtesy of U.S. NRC): General basic features— (1) thermal neutron spectrum; (2) uranium-dioxide (UO2) fuel; (3) fuel enrichment about 3%; (4) direct cycle with steam separator (steam generator and pressurizer are eliminated), i.e., single-flow circuit (single loop); (5) reactor pressure vessel (RPV) with vertical fuel rods (elements) assembled in bundle strings cooled with upward flow of light water (water and water-steam mixture); (6) reactor coolant, moderator and power-cycle working fluid are the same fluid; (7) reactor coolant outlet parameters: Pressure about 7 MPa and saturation temperature at this pressure is about 286°C; and (8) power cycle—subcritical-pressure regenerative Rankine steam-turbine cycle with secondary-steam reheat (for details, see Figure 17b). The largest BWR has installed capacities: 1435 MWel and 4500 MWth.*

#### **Table 5.**

*Selected typical heat-transfer-coefficient (HTC) ranges of various coolants [35].*

*Advances and Challenges of Boiling Heat Transfer DOI: http://dx.doi.org/10.5772/intechopen.114095*

#### **Figure 20.**

*CHF vs. critical quality at flow boiling in vertical bare circular tube (ID 6.92 mm, OD 7.93 mm, heated length 0.45–1.98 m, material Inconel): R-134a,* P *= 1.67 MPa, and* G *= 1000 kg/m2 s. (a) Full scale and (b) the same as in (a), but in enlarge scale. (For details, see [36]).*

The largest by scale and the most expensive experiments are performed in nuclearpower industry to determine the abovementioned flow-boiling characteristics, because any new bundle design or even updated one requires the exact knowledge of these characteristics. Samples of several bundle-string designs and fuel channel are shown in **Figures 25** and **26**, respectively. Also, in nuclear reactors usually axial and radial heat fluxes are not uniform. These specifics increase significantly the complexity of manufacturing test sections/stations (directly-heated with electrical current thin-wall tubes have to be with variable wall thicknesses) (see **Figures 27** and **28**).

**Figure 21.**

*CHF vs. critical quality at flow boiling in vertical and horizontal circular tubes (ID 6.92 mm, OD 7.93 mm, heated length 0.45–1.98 m, material Inconel): R-134a,* P *= 1.31 MPa, and* G *= 2000 kg/m2 s. (For details, see [37]).*

All experiments with bundles are performed with electrically-heated bundle strings, so-called, bundle simulators (for details, see [39, 40]). Therefore, such bundle strings are usually made of Inconel or stainless steel thin-wall tubes and can cost millions of dollars. Also, experimental setups are very sophisticated in terms of measuring devices and require quite large power supplies, e.g., for water experiments with the full-scale bundle string as shown in **Figure 26**, it can be up to 15 MWel, but if modeling fluid (usually, R-134a) is used for additional set of experiments, power requirement can be significantly lower, i.e., up to 1.8 MWel (**Figures 29** and **30**).

To be able to scale operating conditions in water into those of R-134a and vice versa to scale PDO results from R-134a into water data the following scaling laws have been used:

*For pressure:*

$$
\left(\frac{\rho\_f}{\rho\_\lg}\right)\_R = \left(\frac{\rho\_f}{\rho\_\lg}\right)\_W \tag{4}
$$

*Advances and Challenges of Boiling Heat Transfer DOI: http://dx.doi.org/10.5772/intechopen.114095*

#### **Figure 22.**

*CHF vs. critical quality at flow boiling in vertical and horizontal tubes (ID 6.92 mm): R-134a,* P *= 1.67 MPa and G = 500 kg/m2 s.*

*For mass flux:*

$$
\left[\frac{\mathbf{G} \cdot D\_{hy}}{\mu\_{\mathbf{g}}}\right]\_{R} = \left[\frac{\mathbf{G} \cdot D\_{hy}}{\mu\_{\mathbf{g}}}\right]\_{W} \tag{5}
$$

*For PDO HTC:*

$$\left(\frac{h\_{\rm PDO} \ D\_{\rm hy}}{k\_{\rm g}}\right)\_{R} = \left(\frac{h\_{\rm PDO} \ D\_{\rm hy}}{k\_{\rm g}}\right)\_{W}; \text{where} \quad h\_{\rm PDO} = \frac{q}{T\_{w} - T\_{\rm sat}}\tag{6}$$

*x*R = *x*W, where *x* is the thermodynamic quality. *Dimensionless CHF expressed as:*

$$
\left[\frac{q\_{cr}}{G\,h\_{\text{f\text{\text\text\text\text\text\text\text\text}}}\right]\_{R} = \left[\frac{q\_{cr}}{G\,h\_{\text{f\text\text\text\text\text\text\text\text\text\text\text\textdegree}}\right]\_{W} \tag{7}
$$

It should be noted that the most important parameters for BWR/ABWR bundlestring experiments are HTC, CHF, and PDO heat transfer. Moreover, even for PWRs (the largest PWR is the EPR (Evolutionary Power Reactor) by former company Areva, currently, by EDF (France): 1670 MWel and � 4590 MWth) and PHWRs (largest

#### **Figure 23.**

*(a) CHF vs. critical quality and (b) CHF enhancement vs. critical quality—Flow boiling in vertical circular tubes (ID 6.92 mm, OD 7.93 mm, heated length 0.45–2 m, material Inconel) without flow obstructions (i.e., bare) and with various flow obstructions: R-134a,* P *= 1.67 MPa, and* G *= 3000 kg/m2 s. (For details, see [38]).*

*Advances and Challenges of Boiling Heat Transfer DOI: http://dx.doi.org/10.5772/intechopen.114095*

#### **Figure 24.**

*Experimental thermalhydraulics R-134a loop: 1—gear pump; 2—coriolis-type mass flow meter; 3—preheater; —dielectric fittings, 5—Current (power) terminals; 6—electrical preheater; 7—sight glass; 8—condenser; —pressurizer; 10—pressure-relief valve; 11—refrigerant filter-dryer; 12—ball valve; 13—vacuum pump; —refrigerant storage tank; 15—pressure reducer; and 16—N2 container.*

PHWR is the CANDU-9 reactor (CANada Deuterium-Uranium)) by AECL (Canada): 878 MWel and 2750 MWth), which are not cooled with boiling light or heavy water, CHF and PDO at flow boiling should still be determined.

**Figure 31** shows the surface-temperature map for Element 35 at a pressure of 0.98 MPa and mass-flow rate of 9.6 kgs 1 with 28% overpower1 . At high overpowers, dry patches coalesced at some angular locations and the maximum axial dry patch approached the complete length of the element. A full-length axial dry patch on an element could not be measured due to the limited traveling distance of the thermocouple drive unit. Based on the variation of surface temperature with axial distance, the full-element dryout was achieved at several high-power levels.

**Figure 32** shows a new application for boiling process such as an ultimate emergency cooling of the molten nuclear-reactor core (corium) during a severe nuclear

1 Overpower is defined as: channel-power / critical-power

**Figure 25.**

*Designs of fuel-bundle strings or assemblies of two pressurized water reactors (PWRs): (a) square cross section (courtesy & copyright by MHI) and (b) hexahedron cross section (courtesy of ROSATOM) (Photo by A. Antonov, 2015): https://www.flickr.com/photos/rosatom/25761756447/in/album-72157692396689951/ [Accessed: December 10, 2023].*

accident (modern feature for Generation-III+ reactor designs) (for details, see [29]). This new safety feature is in response to the Chernobyl NNP severe accident (April of 1986), when a large pressure-channel reactor (RBMK-1000: 1000 MWel and 3200 MWth) was completely melted, and there was a possibility for a corium to damage a concrete foundation of the reactor).

This new application of the boiling process has started to be implemented in new reactor's designs, but this unusual type of boiling is well-known for the Mother nature *Advances and Challenges of Boiling Heat Transfer DOI: http://dx.doi.org/10.5772/intechopen.114095*

#### **Figure 26.**

*3-D image of pressurized heavy-water reactor (PHWR) fuel channel with 43-element bundle (based on AECL design; prepared by Dr. W. Peiman).*

#### **Figure 27.**

*Sample of stylized axial power profile (APP) or axial heat flux profile (AHFP) used for critical heat flux (CHF) tests and pressure-tube creep profiles: 3.3% for 10–15 years of operation and 5.1% for 20–30 years of operation (based on report COG-98-311) (courtesy and copyright by COG).*

for millions of years, because it is eventually quite close to the cooling of a molten volcano lava in oceans, seas, etc.

In addition, modern Generation-III+ reactors are equipped with Passive-Core-Cooling System (PCCS), which at high heat flux will operate as boiling circulation loop (for details, see [41] or [29]).

More information on boiling, its characteristics, specifics, etc. can be found in the following publications: Boiling: Research and Advances [42]; Pioro et al. [43]; Naterer

*Sample of radial power profiles (RPPs) for CANDU-reactor bundle used for critical heat flux (CHF) tests (based on report COG-98-311) (courtesy and copyright by COG).*

**Figure 29.** *Simplified layout of large (full-bundle-string) thermalhydraulics R-134a loop [39, 40].*

[44]; Pioro et al. [45–47]; Handbook of Phase Change: Boiling and Condensation [48]; Groeneveld et al. [49]; Convective Flow Boiling [50]; Collier and Thome [51]; Lahey and Moody [52]; Whalley [53]; Hanne and Grigull [54]; Davis and Anderson [55]; Thorn et al. [56]; and Bergles and Rohsenow [57].

*Advances and Challenges of Boiling Heat Transfer DOI: http://dx.doi.org/10.5772/intechopen.114095*

*General layout of horizontal test station of MR-3 R-134a thermalhydraulics loop [39, 40]: PDT—pressure differential transducer and PT—pressure transducer.*

#### **Figure 31.**

*Surface-temperature map for element 35 at 28% overpower (actual power to critical power): R-134a, 37-element bundle (for details, see [40]).*

**Figure 32.**

*Containment heat-removal system (CHRS) (courtesy and copyright by AREVA (EDF)). Two fully redundant trains with specific diversified heat sink.*


2.2.2. Virtual Abatement Costs of Pollutants

The virtual abatement costs (*Cva*) generated by the air and water pollution generated during the building life cycle can be quantified based on the bill of quantities and life cycle inventory. The formula is as follows:

$$\mathcal{C}\_{\rm vu1} + \mathcal{C}\_{\rm vu2} = Q\_1 \times c\_{\rm vu1} + Q\_2 \times c\_{\rm vu2} \tag{2}$$

where *Q*1 is the amount of air pollutants, based on LCI; *Q*2 is the amount of water pollutants, based on LCI; *cva*1 is the unit virtual abatement costs of air pollution (see Table 4); *cva*2 is the unit virtual abatement costs of water pollution (see Table 5).

**Table 4.** Unit virtual abatement costs of air pollution (unit: CNY/t).

**Table 5.** Unit virtual abatement costs of water pollution (CNY/kg).


*2.4. Image Evaluation and Segmentation*

Parametric images were produced and quantified using syngo.via® 8.2 (Siemens Healthineers, Erlangen, Germany). Volumes of interest (VOIs) were manually delineated in the fused PET/CT images and validated by a certified expert in nuclear medicine with more than five years of experience in PET/CT. VOIs were overlaid on the Ki dataset, DV-FDG, and on the static PET images for data extraction. If necessary, manual coregistration was performed to assure adequate realignment.


*2.9. Infertility*

The sperm tail has microtubule arrangement (9 × 2 + 2), which is similar to that of motile cilia [55]. Therefore, infertility is frequently observed in males with PCD [54]. There are some differences, however, between the sperm tail and motile cilia, including cell type-specific axonemal proteins

and accessory structures specific to the sperm tail, such as the mitochondrial sheath, fibrous sheath, and outer dense fibers [55]. Mutations in genes causative of PCD are not always associated with male infertility and vice versa [55]. The impairment of the sperm tail affects sperm motility. The impairment of motile and primary cilia also affects the function of the reproductive tract in both males and females [54,56]. Structural and functional studies of cilia associated with infertility constitute an important area in reproductive research [55,56].

### *2.10. Roles of Primary Cilia in Cancer*

Primary cilia in cultured mouse 3T3 fibroblasts and human retinal pigment epithelial (RPE1) cells can be disassembled and assembled by serum stimulation and deprivation, respectively [18,19,94]. Aurora A kinase (AURKA), one of the most important mitotic kinases for cell-cycle control [95], plays important roles in deciliation by serum stimulation [96,97]. AURKA is activated by serum stimulation through Ca2+/calmodulin signaling, the non-canonical WNT pathway, and phosphatidylinositol signaling [97–100]. Serum stimulation also activates AURKA through the pathway involving epidermal growth factor receptor (EGFR), ubiquitin-specific peptidase 8 (USP8), and trichoplein (TCHP) (described in the next section) [33,34,101]. Activated AURKA phosphorylates itself and target proteins during G1 phase, which stimulates the disassembly of primary cilia [97]. Several proteins associated with AURKA and ciliogenesis have been identified, including histone deacetylase 6 [94] and nudE neurodevelopment protein 1 (NDE1) [102]. In response to serum stimulation, NDE1 localizes at the basal body and suppresses ciliogenesis by tethering dynein light chain 1 [103]. Under serum deprivation conditions, cyclin-dependent kinase 5 is activated and phosphorylates NDE1. Phosphorylated NDE1 is then recognized and ubiquitylated by the E3 ligase complex SCFFBXW7, resulting in ciliogenesis [104,105]. Importantly, forced ciliation in cells growing under serum stimulation conditions can cause cell-cycle arrest [33,34,101,102,106]. These findings suggest that the primary cilium can act as a negative regulator of the cell cycle and may be a tumor suppressor organelle [3–6,9,107–109]. In fact, the suppression of primary cilia function is associated with tumorigenesis, cell proliferation, and metastasis in many cancers, including glioblastoma [110], esophageal cancer [111], colon cancer [112], cholangiocarcinoma [113,114], pancreatic ductal adenocarcinoma [115], clear cell renal carcinoma [116], prostate cancer [117], ovarian cancer [118,119], melanoma [120], and chondrosarcoma [121] (Table 2). However, primary cilia can promote tumor progression under certain conditions. In medulloblastoma and basal cell skin carcinoma caused by gain-of-function mutation of SMO, primary cilia convert the GLI transcription factors GLI2 and GLI3 to their activated forms, inducing their translocation to the nucleus, increased transcription of Hedgehog target genes, and promotion of cell proliferation [122,123]. In contrast, primary cilia of medulloblastoma and basal cell skin carcinoma caused by gain-of-function mutation of GLI2 increases the activity of GLI3 as a transcriptional repressor, resulting in suppression of the proliferation of these cancer cells [122,123]. Further work will thus be necessary to fully understand the context-dependent roles of primary cilia in cell proliferation.

### **Table 2.** The roles of primary cilia in cancer.

PC—primary cilia; KD—knockdown; GOF—gain-of-function.

### **3. Roles of E3 Ubiquitin Ligases and DUBs in Ciliogenesis, Ciliopathy, and Cancer**

The structure and function of cilia are dynamically regulated by many ciliary proteins through posttranslational modification [2,4–6,25]. Ubiquitination and deubiquitination of ciliary proteins by E3 ubiquitin ligase and DUBs, respectively, are crucial for the dynamic regulation of cilia [4–6,31–34]. In this section, we briefly describe the role of E3 ubiquitin ligases and DUBs in ciliogenesis, ciliopathy, and cancer (Table 3).

**Figure 1.** Suppression of Kctd17 in zebrafish impairs ciliogenesis in Kupffer's vesicle and induces situs inversus (**A**) Staining of acetylated alpha-tubulin in the cilia of Kupffer's vesicle at 12 h post-fertilization (hpf) of wild-type (control) or Kctd17 knockout (KO) zebrafish. (**B**) Distribution of the cilia length in Kupffer's vesicle at 12 hpf in control or Kctd17 KO or knockdown (KD) zebrafish. (**C**) Representative in vivo images of control and Kctd17 KO zebrafish at 3 days post-fertilization (dpf). Control and Kctd17 KO zebrafish show rightward and leftward looping of the heart, respectively. Please see Video S1. (**D**) At 3 dpf, rightward and leftward looping of the heart is observed in about 95% of the control zebrafish and about 20% of the Kctd17 KO zebrafish, respectively. Scale bar: 20 μm (**A**), 200 μm (**C**).

**Table 3.** The roles of E3 ubiquitin ligases and deubiquitinases in ciliogenesis, ciliopathy, and cancer.

DUBs—deubiquitinases; KD—knockdown; KO—knockout; OE—overexpression; LOF—loss-of-function.


**Author details**

and more usefully used even about the delicate but fundamental issue of sustainable tourism. Obviously, political institutions may have used other social media rather than Twitter, and any finding of the research should be tested in alternative contexts. Notwithstanding this limitation, the research did confirm the very substantial problem posed by Derrida [20]

Even in the narrow analytical space of Twitter texting, a distance between "scientific," "politi-

In its reality, the perception of sustainable tourism may be plural, depending on the language and the grammar of very different discourses. There is a specific discourse for any of different circles, those of researchers, policymakers, and the common people on vacation. These latter

This finding should not be underrated for any future research, ever beyond the strict area

In responding to the posed research questions, from the case study, it appears that users of tourist services and destinations do tweet for talking about any destination referring to some self-evident qualifications such as being the resort "on the sea" and "having a sunny beach." Detected texts are quite all oriented to narrate the leisure aspects of the singular destinations rather than their environment and sustainability. The fact that environmental features seem to be tacit and given by twittering tourists, should be considered not as a scarce attention to the environment, but in the context of a popular discourse. People are neither scientists nor policymakers but do have cogent opinions. It is important to underline that no differences

Then, it is quite evident that public bodies use Twitter neitherto promote theirinstitutional activities nor for web listening to extract useful knowledge, notwithstanding they have social media accounts. In this condition, co-creation seems to be an item far from reality and "sustainable tourism," an expression indicating a per se evident feature, not necessitating a more committed attention. This is not a good thing because co-creation for giving sense to sustainable tourism has the necessity to use a common discourse to be capable of producing an effective behavior.

It should be lastly stressed that the main limit of the research consists in having only Twitter being used and not also Instagram or Facebook, and other social media actually used by com-

Results of the present work should be useful both for research and economic or political purposes. The realms of private companies, public administrators, and policymakers involved in tourism should benefit from easy and free procedures for analyzing online conversations for sustaining policies and interventions. Researchers and destination managers would be also interested in the existing divide between official documents and statements on sus-

cal," and "popular" approach to the definition of sustainable tourism is confirmed.

speak about environmental problems only when occasionally must face them.

on textuality of ideas and concepts.

120 Mobilities, Tourism and Travel Behavior - Contexts and Boundaries

of web content analysis.

emerged between the Italian and Croatian coasts.

**5. Follow up and further steps**

panies, tourists, and public bodies for their different purposes.

tainable tourism and the reality of popular perception of the issue.

Gian Luigi Corinto\* and Fabio Curzi

\*Address all correspondence to<EMAIL_ADDRESS>
Department of Education, Cultural Heritage and Tourism, The Section of Environment and Territory, University of Macerata, Italy